International Journal of Modern Physics: Conference Series

Rapid growth of electronic industry requires development of new materials that combine the high dielectric constant intrinsic to ferroelectric ceramic materials with easy processing characteristics of polymers. Ceramic-polymeric composites possess interesting properties for a variety of electronic applications including passive electronic devices. In fact, polymer-ceramic materials have drawn lot attention for use in microelectronic packaging, because they can give higher performance with lower cost, size and weight.

In this work, attempts are made to prepare ceramic polymer composites followed by characterization of dielectric properties. The Barium Titanate ceramic powders are synthesized using the hydrothermal process. Crystal structure and crystallite size of particles are determined using X-ray diffraction. Silane treatment is carried out on Barium Titanate powder to increase its compatibility with polymer, followed with preparation of ceramic polymer composites. Epoxy and polyvinyledene fluoride (PVDF) polymers are used as matrices for preparation of the composites. The proportion of nanopowder is varied from 60 to 90 wt%. Dielectric properties such as volume resistivity, dielectric constant, dissipation factor are evaluated. Results indicate that the dielectric constant and dissipation factor vary between 18 -140 and 0.01 to 0.09, respectively as the relative ratio of polymer and silane modified Barium Titanate is varied. Specifically, at 90 wt% of 0.1 wt% silane modified Barium Titanate, the highest dielectric constant of 140 along with dissipation factor of 0.07 is obtained in the epoxy based system.

Renewable energy is increasingly viewed as critically important globally. Solar cells convert the energy of the sun into electricity. The method of converting solar energy to electricity is pollution free, and appears a good practical solution to the global energy problems. Energy policies have pushed for different technologies to decrease pollutant emissions and reduce global climate change. Photovoltaic technology, which utilizes sunlight to generate energy, is an attractive alternate energy source because it is renewable, harmless and domestically secure. Transparent conducting metal oxides, being n-type were used extensively in the production of heterojunction cells using p-type Cu₂O. The long held consensus is that the best approach to improve cell efficiency in Cu₂O-based photovoltaic devices is to achieve both p- and n-type Cu₂O and thus p-n homojunction of Cu₂O solar cells. Silicon, which, next to oxygen, is the most represented element in the earth's crust, is used for the production of monocrystalline silicon solar cells. Silicon is easily obtained and processed and it is not toxic and does not form compounds that would be environmentally harmful. In contemporary electronic industry silicon is the main semiconducting element. Thin-film cadmium telluride (CdTe) solar cells are the basis of a significant technology with major commercial impact on solar energy production. Polycrystalline thin-film solar cells such as CuInSe₂ (CIS), Cu (In, Ga) Se₂ (CIGS) and CdTe compound semiconductors are important for terrestrial applications because of their high efficiency, long-term stable performance and potential for low-cost production. Highest record efficiencies of 19.2% for CIGS and 16.5% for CdTe have been achieved.

The ZnO film prepared by doctor blade method are highly porous in presence of structure directing agent PEG and then can be easily sensitized by various molecules. In the present work, the nanostructured ZnO/dye hybrid film prepared by doctor blade method has been investigated in conductivity and photoconductivity measurements in view of applications in dye-sensitized solar cells (DSSC) and in optoelectronics, since electron transport in these devices plays a decisive role for the electron collection efficiency and therefore for the overall efficiency. The absorption of ZnO film sensitized by Rose Bengal dye (RB) has been studied by UV spectroscopy which indicates that after the dye is adsorbed on the ZnO electrode, its absorption spectra showed red-shift in the peak position compared to the absorbance spectra of dye in ethanol. Highly porous ZnO films are found to have high dark conductivity, probably because of a higher n-doping, which is due to higher concentration of Zn atoms in the film. On the other hand, ZnO/RB hybrid film is found to show a much higher sensitivity to illumination with visible light in photoconductivity measurements due to a higher absolute photoconductivity and lower conductivity in the dark.

Precise knowledge of the elastic properties of MgO periclase, under high-pressure condition is therefore crucial for constructing the accurate mineralogical model of the Earth's lower mantle. In present work an attempt has been done to calculate the pressure dependence elastic properties such as isothermal bulk modules (K_T), Young's modulus of elasticity Y and shearing stress G for geophysical MgO by using three deferent phenomenological EOS viz. the Born-Mayer EOS, Murnaghan EOS and Birch EOS. The result shows that the value of elastic parameter as calculated by using Murnughan EOS and Birch EOS shows close agreement with each other while Born-Mayer EOS shows deviation in calculated values.

Single phase nanocrystalline soft magnetic Mg_0.7-xNi_0.3Zn_xFe₂O₄, ferrites with x = 0.0 − 0.7 were prepared by sol gel auto-combustion method. X-ray diffraction confirms the formation of single phase nano-crystalline cubic spinel ferrites with average grain diameter ranging between 12.9 nm to 23.9 nm. Formation of the ferrite phase without subsequent heat treatment makes sol-gel auto combustion technique especially suitable and economical for the large scale industrial production of the nano-crystalline ferrites for multilayer chip inductor applications (MLCI). Both, lattice parameter and X-ray density shows a linear increase with increasing Zn²⁺ concentration, attributed to the difference in ionic radii and density of Mg and Zn. Increase in Zn content enhances the soft magnetic behavior, exhibiting linear decrease of coercivity from 122.34 Oe to 72.45 Oe, explained by increase of density with Zn addition. The maximum magnetization (M_max)increases up to 0.106 Tesla (for x = 0.4) and. then decreases with increase of Zn content, discussed on the basis of increase of the occupancy of A-site in spinel ferrite by non-magnetic Zn²⁺ ion.

To understand the mechanism and structure of superconductor of type Bi₂Sr₂Ca_n−1Cu_nO_x (n=1,2,3), the great interest has developed in the structure and physical properties of compound with structure formula (Bi₂M_1+nTM_nO_x), where m= Sr,Ba,Ca, and this transition metal other than Cu, so for compound reported belongs to group which contain transition metal such as iron, cobalt, manganese etc. some more study using iron as transition metal is reports for Bi₂Sr_1+nfe_nO₂ for n=2. In the present work we are interested the study of synthesis and characterization of compounds which are isosrtructural to the 2223 Bismuth superconductor. for example Bi₂Sr_4−xCa_xfe_3−yCu_yO₂ to be synthesis with different amounts by XRD method.

Thermal conductivity and thermal diffusivity of blended clays have been studied with special reference to Ukrainian clay. The blends were made of three different clays available locally in western part of Rajasthan. Thermal conductivity and thermal diffusivity were determined using the transient plane source (TPS) technique at room temperature and normal pressure. It was found that thermal conductivity and thermal diffusivity of the blends reported maximum at temperature 1200° C and near in the values of Ukrainian clay. The thermal conductivity of blend B2 reported maximum value (1.29 W/m-k) in the present study.

Different kaolin clay specimen exhibit varying colours after firing depending upon the relative presence of different mineral impurities, physical state of mineral constituents etc. Spectrophotometers used for determining colour values generate many sets of colour data. Interpretation of such colour values is a subjective matter. Increase in darkness, yellowness etc as a consequence of increase in chromophore impurity content in kaolin clay have been shown. However, the inverse of above ie; gradual change in colour values along with gradual change in chromophore impurity content over a realistic range has not been studied. Whether the colour data of kaolin clay after firing can be taken up as a function of impurity content needs to be investigated. Thus, to identify the correlation between kaolin clay impurity content and it's fired colour data the present investigation examined the hypotheses i) The colour development after firing of kaolin clay is an indicator of chromophore impurity content present therein and ii) All the colour variables (L, a, b, ISO2470, redness) constituting a colour data set of pressed kaolin clay specimen after firing will vary in similar manner such that to represent variation in impurity content. The study indicated that the colour values obtained by spectrophotometry of clay specimens after firing represent the chromophore impurity present therein in a less reliable manner. To relatively estimate the quantity of chromophore impurity present in a clay sample from its fired colour, the sample should be mixed with 50% by weight of potash feldspar, pressed in to tablet suitable for colour measurement and fired at or above 1220°C to vitrify. After that the ‘L’, ‘a’ and ‘ISO2470’ values obtained truly represent the chromophore present therein.

The usability of waste rock (rock residue) powder as an additive material in ceramic samples was investigated. Qualitative analysis was carried out to determine the major and minor constituent minerals present in ceramic bodies made from rock residue powder by using FT-IR spectroscopic technique. Further, the representative ceramic bodies are analyzed by FT-IR technique to yield more information about the functional groups and also to estimate the order or disorder of kaolinite structure.

Biodiesel is a renewable liquid fuel made from natural, renewable biological sources such as edible and non edible oils. Over the last years, biodiesel has gained more market due to its benefits and because it appears as the natural substitute for diesel. Reasons for growing interest in biodiesel include its potential for reducing noxious emissions, potential contributions to rural economic development, as an additional demand center for agricultural commodities, and as a way to reduce reliance on foreign oil. Biodiesel was prepared from soybean oil by transesterification with methanol in the presence of cement clinker. Cement clinker was examined as a catalyst for a conversion of soybean oil to fatty acid methyl esters (FAMEs). It can be a promising heterogeneous catalyst for the production of biodiesel fuels from soybean oil because of high activity in the conversion and no leaching in the transesterification reaction. The reaction conditions were optimized. A study for optimizing the reaction parameters such as the reaction temperature, and reaction time, was carried out. The catalyst cement clinker composition was characterized by XRF. The results demonstrate that the cement clinker shows high catalytic performance & it was found that the yield of biodiesel can reach as high as 84.52% after 1 h reaction at 65°C, with a 6:1 molar ratio of methanol to oil, 21 wt% KOH/cement clinker as catalyst.

A sol-gel based TiO₂ thin film was applied on glazed wall tiles for studying its various functional properties. Thin film was deposited by spin coating on the substrate and subjected to curing at different temperatures such as 600°C, 650, 700°C, 750°C and 800°C with 10 minutes soaking. The gel powder was characterized by FTIR, DTA/TG and XRD. Microstructure of thin film was analyzed by FESEM and EDX. Surface properties of the coatings such as gloss, colour difference, stain resistance, mineral hardness and wettability were extensively studied. The antibacterial activity of the surface of coated substrate against E. coli was also examined. The durability of the coated substrate in comparison to the uncoated was tested against alkali in accordance with ISO: 10545 (Part 13):1995 standard. FESEM images showed that thin films are dense and homogeneous. Coated substrates after firing results in lustre with high gloss, which increased from 330 to 420 GU as the curing temperature increases compared to that of uncoated one (72 GU). Coated substrate cured at 800°C shows higher mineral hardness (5 Mohs’) compared to uncoated one (4 Mohs’) and films cured at all temperatures showed stain resistance. The experimental results showed that the resistance towards alkali attack increase with increase in curing temperature and alkali resistance of sample cured at 800 °C was found to be superior compared to uncoated substrate. Contact angle of water on coated surface of substrates decreased with increase in temperature. Bacterial reduction percentages of the coated surface was 97% for sample cured at 700°C and it decreased from 97% to 87% as the curing temperature increased to 800 °C when treated with E. coli bacteria.

Khargone district is located at the southwest border of Madhya Pradesh. The district comprises of many archaeological and historical sites viz. Navdatoli, Maheshwar, Kasrawad, Mandleshwar. Archaeological excavations at these sites revealed vast cultural assemblage from Lower Paleolithic to Medieval Period. Pottery plays significant role in the reconstruction and understanding of past technologies and socio-economic-religious life. Present paper endeavors to understand contemporary traditional pottery practices at these sites. Besides documentation of degeneration of technology, authors aim to put forth the survival problems of the potters. Furthermore, an attempt has been made to examine the possible reasons behind their present socio-economic conditions.

The process of coal combustion results in coal ash, 80% of which is very fine in nature & is thus known as fly ash. Presently, in India, about 120 coal based thermal power plants are producing about 90-120 million tons of fly ash every year. With increase in demand of power energy, more and more thermal power plants are expected to commission in near future and it is expected that fly ash generation will be 225 million tons by 2017. Disposal of fly ash requires large quantity of land, water and energy and its fine particles, if not disposed properly, by virtue of their weightless, can become air born and adversely affect the entire Environment. These earth elements primarily consist of silica, alumina & iron etc. and its physicochemical parameters are closely resembles with volcanic ash, natural soil etc. These properties, therefore, makes it suitable for use in ceramic industries and helps in saving the environment and resources.

The region covering Southeastern Anatolia takes place in upper Mesopotamia, so it has numerous cultural heritages due to its witness to various social movements of different civilizations in ancient times. Kuruki Mound is located on the junction point of Tigris River and Batman Creek, near Oymatas village which is almost 15 km to Batman, Turkey. The mound is dated back to Late Chalcolithic. Archaeological excavations are carried out on two hills named as “Kuriki Mound-1” and “Kuriki Mound-2” in which 4-layer and 2-layer settlements have been revealed, respectively. This region will be left under the water by the reservoir lake of Ilısu Dam when its construction is completed. Thus, characterization of ancient materials such as potsherds, metals and skeleton ruins should be rapidly done. In this study, 12 potsherds excavated from Layer-1 (the first settlement layer after the surface) in Kuriki Mound-2 were investigated by FT-IR spectrometry. Energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) analyses were used as complementary techniques in order to expose chemical and mineralogical/phase contents, respectively. Obtained results showed that the potteries have been produced with calcareous clays and they include moderate amounts of MgO, K₂O, Na₂O and Fe₂O₃ in this context. Additionally, high temperature phases have also been detected with XRD analyses in some samples.

Positron annihilation lifetime spectra (PLAS) have been measured for natural rubber polymer with different fillers (Titenium dioxide, Nanosilica and Nanoclay) as a function of filler concentration to investigate how these fillers affect the microstructure of free volume of natural rubber. The lifetime spectra is analyzed by using LT9.0 and the longest lived component(τ_o-Ps) is attributed to the pick- off annihilation of o-Ps in free volume sites, available mostly in the amorphous region of polymer. On the basis of the τ_o-Ps values the radii of the free volume holes (R_h) are calculated. The PALS results show that o-Ps lifetime as well as the size of free volume decreases with the increase of filler concentration.

This paper reports the thermo physical characteristics of Vitrified tile polishing waste materials. As such growing production of vitrified tiles in the country generate large volume of this waste obtained during processing, polishing and cutting of the vitrified tiles to the tune of nearly 10-15 tonnes per day from each plant. The characteristic features of these materials are being studied and investigated to develop suitable technology for finding its gainful use especially in the traditional ceramics. It is known that ceramic as such building materials industry could be a large raw materials consumer and being heterogeneous and thus could utilize this vast quantity as the raw materials. However, the main problem would be it's firing nature as it showed thermal deformation after a particular temperature. Interestingly, the production process of most of the traditional ceramics follows a similar pattern starting from the raw materials processing up to a level of firing. Hence, to suggest suitable utility in the traditional ceramics as raw materials, it was the prime requisite that these waste must be thoroughly studied w. r. t various thermo physical characteristics to make use in this sectors. Hence, the present paper interestingly gone up to various study such as raw materials nature, particle size distribution, chemistry, XRD and DTA study for understanding typical physico chemical properties, and finally thermal properties to make it suitable for use in traditional ceramic industries. The higher fineness of the waste materials indicates its usefulness without extra grinding. The chemistry of typical sludge shows contamination from abrasive particles, sorrel cement bonding materials etc. originated from the polishing wheel and needs special precaution while suggesting use in the ceramic sectors. The firing characteristics of the sludge materials produces a foamy and spongy shapes and this could be the main guiding parameters in selecting the end use of the waste materials w. r. t temperature. The present study only shows various characteristic features of this waste and focuses its important properties to be used as a raw material in large quantity in the ceramic industries.

The existence of an epitaxially stabilized tetragonal-like (“T -like”) monoclinic phase in BiFeO₃ thin films with high levels of compressive strain has been reported recently. While their structural and ferroelectric properties are different from those of rhombohedral-like (“R-like”) films with lower levels of strain, little information exists on magnetic properties. In this study we have applied a short range force constant model by using normal coordinates to investigate the Raman and the infrared wavenumbers in tetragonal BiFeO₃ having space group P4mm (C₄v¹). The calculation of zone center phonons has been made by using three stretching and six bending force constants. The calculated Raman and infrared wavenumbers are in very good agreement with the observed ones. The potential energy distribution has also been investigated for determining the significance of contribution from each force constant toward the Raman and the infrared wavenumbers.

Nanocrystalline BaTi_0.095W_0.05O₃ has been synthesized by mechanical activation process using high-energy ball milling. The powders milled for (10 hours, 20 hours, 30 hours respectively) were characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). Transmission electron microscopy images showed that in W- substituted barium titanate nanoparticles are formed in the range of 20–50 nm. Crystallite size decreases with increasing milling time in the samples. Detailed Dielectric and ferroelectric properties with different milling times are discussed in detail. Diffusivity of the samples increases with milling time. Piezoelectric properties increase with increase in milling time in the samples.

Butyl rubber — Ca₄La₆(SiO₄)₄(PO₄)₂O₂ — composites have been prepared by sigma mixing and hot pressing. The relative permittivity of the composites varies from 3 to 5.3 at 1 MHz. All the composites show low dielectric loss of the order of 10⁻³ at 1 MHz. The experimentally observed values of relative permittivity are correlated with those calculated using various theoretical models. The composites show good temperature stability of relative permittivity.

The tetragonal Ca₉Nd₂W₄O₂₄ (CNW) ceramic was prepared by the conventional solid state ceramic route and their dielectric properties were investigated in the radio and microwave frequencies. The CNW ceramics sintered at 1450 °C for 4 h showed a densification 92 % with ε_r = 16 and tanδ = 0.004 at 15.1 GHz. The thermal conductivity of ceramic at room temperature was found to be 1.6 W m⁻¹K⁻¹ and coefficent of thermal expansion of CNW ceramics was 4.2 ppm/°C measured in the range of 25 to 600 °C. The dielectric and thermal properties of CNW ceramic are reported for the first time.

Aluminium phosphate (AlPO₄)-Magnesium fluoride (MgF₂) composite has been prepared through solid state ceramic route. The formation of composite has been confirmed by X-ray diffraction studies. The variation in ε_r and tanδ of the composite with frequency in the range (1K Hz – 3 MHz) has been studied. The AlPO₄-MgF₂ has a small temperature dependence of ε_r. The composite shows low relative permittivity of 3 and low dielectric loss (tanδ = 7×10⁻³) at 5.85 GHz.

Different morphologies (spherical, flake and rod) of cobalt ferrite were synthesized using cobalt salt, iron salts, hydrazine hydrate (as a precipitating agent) and CTAB (surfactant) in water as well as ethylene glycol solvents. Four different synthesis ways (HIS, SIH, HISCO and HISG) were adopted to synthesize cobalt ferrite nanopowders using precipitation method. The as-prepared powders obtained after different synthesis ways were calcined at 800°C and structure, microstructure as well as magnetic properties are studied. X-ray diffraction (XRD), scanning electron microscope (SEM) and magnetization studies using pulsed field loop tracer were employed to characterize these cobalt ferrite powders, prepared using different precipitation ways. All the samples are identified with single phase cobalt ferrite and the crystallite size was found to be around 40 nm. Nearly spherical (multifaceted), rod with flake-like, nearly spherical and rod-like morphologies are obtained while synthesizing using HIS, SIH, HISCO and HISG ways, respectively. Rod with flake-like (SIH sample) and rod-like morphologies (HISG sample) show higher coercivity, than the spherical-like (SIH and HISCO smaples) morphology. The highest coericivty was found to be around 925 Oe for HISG sample and highest magnetization is 67 emu/g for HISCO sample.

We report a novel synthesis technique of ceria nanoparticles by a sol-gel type chemical process using poly-vinyl alcohol (PVA) as a capping as well as a reducing agent. The as-synthesized CeO₂ nanoparticles were characterized by X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The XRD analysis reveals the fluorite type face centered cubic structure in the ceria nanoparticles with an average crystallite size of 6 nm and 9 nm for the samples calcined at 350°C and 400°C, respectively.

The effect of glass fluxing and isovalent substitution on the microwave dielectric properties of low permittivity Sr₂Al₂SiO₇ (SAS) ceramic has been investigated. X – ray diffraction pattern of all the compositions indicate the formation of tetragonal Gehlenite type ceramics with space group (no. 113). The addition of small amounts of lithium magnesium zinc borosilicate (LMZBS) glass to Sr₂Al₂SiO₇ ceramic enhanced the densification. Glass fluxing also improved the quality factor and relative permittivity. A small partial substitution of Al³⁺ and Si⁴⁺ by Ga³⁺ and Ge⁴⁺ was found to degrade the dielectric properties of SAS ceramic. The composition Sr₂Al₂SiO₇ + 1 wt. % LMZBS glass showed the best dielectric properties with ε_r = 7.3, Qu×f = 36000 GHz and τ_f = −23.0 ppm/°C.

The polycrystalline samples of GdFe_1-xNi_xO₃(x=0.0, 0.1) are prepared by solid state reaction route, their structure is analyzed by powder X-ray diffraction (XRD) and Rietveld refinement. We are also studying the behavior of dielectric constant (ε′), tangent loss (tan δ) as a function of frequency from 75 kHz to 5 MHz and AC conductivity (σ_ac) from 75 kHz to 1 MHz for both the compositions at room temperature. It is noticed that Ni³⁺ ion substitution results in lattice contraction and enhancement in dielectric constant, tangent loss and AC conductivity.

Joining of metal with ceramics has become significant in many applications, because they combine properties like ductility with high hardness and wear resistance. By friction welding technique, alumina can be joined to mild steel with AA1100 sheet of 1mm thickness as interlayer. In the present work, investigation of the effect of friction time on interlayer thickness reduction and bending strength is carried out by factorial design. By using ANOVA, a statistical tool, regression modeling is done. The regression model predicts the bending strength of welded ceramic/metal joints accurately with ± 2% deviation from the experimental values.

The joining of ceramic and metals can be done by different techniques such as ultrasonic joining, brazing, transient liquid phase diffusion bonding, and friction welding. Friction Welding is a solid state joining process that generates heat through mechanical friction between a moving workpiece and a stationary component. In this article, numerical simulation on thermal analysis of friction welded ceramic/metal joint has been carried out by using Finite Element Analysis (FEA) software. The finite element analysis helps in better understanding of the friction welding process of joining ceramics with metals and it is important to calculate temperature and stress fields during the welding process. Based on the obtained temperature distribution the graphs were plotted between the lengths of the joint corresponding to the temperatures. To increase the wettability, aluminium sheet was used as an interlayer. Hence, numerical simulation of friction welding process is done by varying the interlayer sheet thickness. Transient thermal analysis had been carried out for each cases and temperature distribution was studied. From the simulation studies, it is found that the increase in interlayer thickness reduces the heat affected zone and eventually improves the joint efficiency of alumina/aluminum alloy joints.

Friction welding is a solid state joining process of joining either similar or dissimilar materials. Joining of ceramic/metal joints by friction welding has opened up new possibilities in many engineering applications. In the present work, thermal modeling of friction welding process has been carried out. Using Finite Element Approach (FEA), analytical solutions were arrived for different ceramic/metal combinations. The temperature distributions of cylindrical surfaces of the alumina and the metals are found by means of 1D heat transfer assumption considering the effect of convection. In the thermal analysis, interfacial temperature and thermal conductivity of the material play a significant role. Based on the obtained temperature distribution the graphs are plotted between the length of the joint and the temperatures. Thus the knowledge of the temperature joint distribution could be helpful in predicting the thermal cycle of the process, microstructure evolution and residual stress formation. Thus the obtained graph helps to study and predict the temperature distribution of both the materials.

The structural and magnetic measurements have been carried out on La_0.67Sr_0.33Mn_0.93Zn_0.07O₃ (LSMZO) polycrystalline sample. The sample has been prepared through Sol-Gel route. X-ray diffraction (XRD) pattern confirms the single phase nature of the sample with orthorhombic crystal symmetry. Field dependent magnetization shows the hysteresis loop with very low coercive field and the magnetization does not saturate up to the field of 5000 gauss in magnitude.

Various compositions with x=0.01, 0.05, 0.10, 0.20 and 0.30 in the system SrTi_1-xMn_xO₃ were prepared by solid state ceramic route. Compositions with x ≤ 0.10 were found to be single phase solid solution. In this paper, the result of investigations on the effect of manganese substitution in SrTiO₃ on dielectric behaviour for the compositions with x ≤ 0.10, which form single phase solid solution have been reported. Average grain size is small, this may be due to segregation of dopant at grainboundaries. Dielectric measurements were made in the temperature range 150–500K. Measurements of dielectric properties show that there is not much space charge polarisation across the grains and grainboundaries interface. This space charge polarisation only occurs at high temperature and one observes large dispersion of dielectric constant and dissipation factor. At low temperatures, dielectric behaviour follows the character of SrTiO₃ with only difference in the values of dielectric constant.

Nano ceramic Diopside (CaMgSi₂O₆) powders are synthesized by Solution Combustion Process(SCS) using Calcium nitrate, Magnesium nitrate as oxidizer and glycine as fuel, fumed silica as silica source. Ammonium nitrate (AN) is used as extra oxidizer. Effect of AN on Diopside phase formation is investigated. The adiabatic flame temperatures are calculated theoretically for varying amount of AN according to thermodynamic concept and correlated with the observed flame temperatures. A “Multi channel thermocouple setup connected to computer interfaced Keithley multi voltmeter 2700” is used to monitor the thermal events during the process. An interpretation based on maximum combustion temperature and the amount of gases produced during reaction for various AN compositions has been proposed for the nature of combustion and its correlation with the characteristics of as synthesized powder. These powders are characterized by XRD, SEM showing that the powders are composed of polycrystalline oxides with crystallite size of 58nm to 74nm.

In Bhilai Steel Plant (BSP), soaking pits are used for heating ingots for successive rolling into blooms. Pits are operated at a temperature of around 1350°C. Mixed gas (Mixture of Blast Furnace gas & Coke Oven gas) of calorific value around 2040 kcal/Nm³ is used as fuel. The walls of soaking pits were lined with traditional 38% Al₂O₃ firebricks and top 500mm was cast with 70% Al₂O₃ low cement castable (LCC). This type of lining results in frequent damages due to hitting by ingots while being lifted from pit by overhead cranes thus affecting the availability of pit. Life of pits was 2 to 2.5 years in BSP with 3-4 cold repairs and 3-4 hot repairs. Energy loss through the wall is also quite high in this type of lining.

To triumph over the limitations of the conventional lining, a lining design was developed for the walls which consist of special 70% Al₂O₃ LCC having high hot strength (HMOR) in combination with specially design flexible SS-304 anchors. Ceramic fiber blanket and insulation bricks were provided between castable and the metallic shell of the pit to minimize the heat loss. A heating schedule was developed and introduced based on available infrastructure at BSP for proper curing of modified LCC based lining.

After introduction of modified lining, pit no. 14/2 is running for more than 2.5 years without any repair. To capitalize the success, two more pits i.e. 12/1 and 9/2 were converted to modified lining. These pits are also running satisfactorily for more than 1.5 years. The modification has resulted in higher availability with substantial increase in production. Shell temperature of the modified pits reduced to 90° – 140°C from 120° – 200°C of conventional pits. This shows reduction in heat loss through walls, resulting less fuel consumption and energy saving of about 18%.

The challenges of improving sintered MgO raw materials with special high temperature properties demand higher temperature calcination. In the process of dead burning of magnesite (DBM) in rotary kiln, the heat expenditures were found to be mainly due to dead burning of magnesite, loss through exhaust gases, loss through kiln shell by radiation & convection, clinker exit etc. The calcination process is highly energy intensive and involves various interdependent variable factors. An attempt was made to build a model and a screening design of experiment was performed with few process variables to identify the greatest effect of variables on the response quality. The design variables chosen were raw magnesite (RM) feed rate, kiln rotation (RPM), fuel consumption and burning zone temperature (BZT). The response variables were exit gas temperature and density of dead burnt magnesite (DBM). A fractional factorial design was used to keep the number of experimental runs to a minimum. ANOVA and normal plots were used to evaluate the effects of different variable factors on the sensory/response properties. The Experimental Design, ANNOVA, Response surface etc. given an insight of dead burning of magnesite in rotary kiln. This work had enabled us to correlate the BZT, RPM, RM feed with the exit gas temp and density of magnesite produced. The result opens up an avenue to look into the optimum region of operations within the ranges of variables considered in order to minimize the exhaust gas temp. and to maximize the density of the DBM produced.

White wares produced worldwide represent the foundation of much of the ceramic industry; Porcelain bodies fabricated from triaxial mixtures of clay, quartz and feldspar with different size and amounts of nano particles were investigated. Although the purity of raw materials has a strong effect on the colour of the fired bodies, the particle size of raw materials also effect the whiteness The raw material mining minerals china Clay, Feldspar, quarts were prepared of various sized nano particles contains 10.60 -20.22%, 56.84- 70.80 % and 34.87-50.76 % of 100nm respectively. The fired bodies of raw mining minerals and triaxial bodies were subjected to colour measurement. The differences in whiteness were compared and discussed. The studies so far carried out is upto 400 mesh size while the present study has included up to 100nm particle size. A statistical correlation between whiteness of feldspar and triaxial body was also carried out. The correlation between china clay and triaxial body are 0.53, 0.57 and 0.66 for china clay similarly correlation for feldspar is 0.49, 0.73 and 0.83 for triaxial body it are 0.97, 0.84 and 0.75 for A1, A2 and A3 samples. Correlation between china clay and feldspar with triaxial body are 0.79 and 0.92 respectively.

The improved safety margins in complex systems have attained prime importance in the modern scientific environment. The analysis and implementation of complex systems demands the well quantified accuracy and capability of measurements. Careful measurement with properly identified and quantified uncertainties could lead to the actual discovery which further may contribute for social developments. Unfortunately most scientists and students are passively taught to ignore the possibility of definition problems in the field of measurement and are often source of great arguments. Identifying this issue, ISO has initiated the standardisation of methodologies but its Guide to the Expression of Uncertainty in Measurement (GUM) has yet to be adapted seriously in tertiary education institutions for understanding the concept of uncertainty. The paper has been focused for understanding the concepts of measurement and uncertainty. Further a case study for calculation and quantification of UOM for high voltage electrical testing of ceramic insulators has been explained.

The binary glassy systems 60V₂O₅-(40-x)P₂O₅ –xB₂O₃ were prepared by melt quenching technique. The mole of B₂O₃ was varies from 5 to 20 mol % with constant mol % of V₂O₅ during preparation of glass samples. The dc electrical conductivity of samples was measured in temperature range 303-473 K and found to be higher for sample 60 V₂O₅-20P₂O₅ –20B₂O₃. Using the Arrhenius equation of conductivity, the activation energy of conduction is estimated. The conduction in these glasses is takes place by phonon-assisted hopping between the localized states.

So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses containing three types of alkali ions. In the present work, the mixed alkali effect (MAE) has been investigated in the glass system (40–x) K₂O–x Li₂O –10Na₂O–50B₂O₃.(0≤x≤40 mol%) through density and modulated DSC studies. The density and glass transition temperature of the present glasses varies non-linearly exhibiting mixed alkali effect. We report the mixed alkali effect in the present glasses through optical properties. From the absorption edge studies, the various values of optical band gap (E_o) and Urbach energy (ΔE) have been evaluated. The values of E_o and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. The band gap energy based average electronic polarizability of oxide ions α_O2–(E_o), optical basicity A(E_o), and Yamashita–Kurosawa’s interaction parameter A(E_o) have been examined to check the correlations among them and bonding character. Based on good correlation among electronic polarizability of oxide ions, optical basicity and interaction parameter, the present K₂O– Li₂O–Na₂O–B₂O₃ glasses are classified as normal ionic (basic) oxides.

Synthetic hydroxyapatite (HA), an analogue of the mineral component of bone tissue has been widely used in medicine as bone replacing material. To impart specific properties, HA can be chemically modified by anionic and cationic substitutions during synthesis. Thus the present study was focused in synthesizing nanocrystalline Ti, Ag and F co-substituted HA by microwave synthesis. The prepared powders were characterized by XRD and FTIR for their crystal size, cystallinity and functional groups respectively. XRD spectra reveal that crystal size of prepared powders was in the range of 21–25 nm in as synthesized condition and 45–51 nm in 900 ˚C heat-treated condition. Complete decomposition of HA to tri calcium phosphate was observed for Ti substituted HA powder after heat-treatment. Addition of F improved the thermal stability of Ti substituted HA as indicated by predominant phase of HA after heat-treatment. The photocatalytic activity of co-substituted HA powders was examined by degradation of methylene blue (5 × 10⁻⁵ M concentration) under visible light irradiation and the results were compared with pure HA. The degradation efficiency of co-substituted HA with respect to methylene blue was twice as high as that of pure HA. Ti and Ag has improved the visible light photocatalytic activity of HA, further F co-substitution has not affected the photocatalytic activity of substituted HA. The antibacterial effect of prepared powders was observed against 1 × 10⁵ cells/mL of Escherichia coli using spread plate method at 24 h incubation period. Ag co-substituted HA showed complete inhibition of growth of Escherichia coli. Thus, among Ti, Ti-F, Ti-F-Ag substituted HA powders, Ti-F-Ag co-substituted HA with excellent visible light photocatalytic activity and anti-bacterial property is expected to be a potential candidate for biomedical applications.

Mixed alkali tungsten borate glasses xLi₂O–(30–x) K₂O–10WO₃–60B₂O₃ (0 < x < 30) were prepared from the melts. These glasses were characterized using X-ray diffraction, differential scanning calorimetry and density measurements. Optical absorption studies were carried out as a function of alkali content to look for mixed alkali effect (MAE) on the spectral properties of these glasses. From the study of ultraviolet absorption edge, the optical band gap energies and Urbach energies were evaluated. The average electronic polarizability of the oxide ion, optical basicity and the interaction parameters were also evaluated for all the glasses. Many of these parameters vary non-linearly exhibiting a minima or maxima with increasing alkali concentration, indicating the mixed alkali effect. An attempt is made to interpret MAE in this glass system in terms of its glass structure.

Electron paramagnetic resonance (EPR) and optical absorption spectra of copper ions in xLiF-(50-x)Li₂O-20SrO-30Bi₂O₃ glass system have been studied. MDSC studies showed that the glass transition temperature decreases with LiF content. Optical absorption spectra of the pure glasses reveled that the cut off wave length increased and optical band gap energy decreased with increase in LiF content. EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu²⁺ ions. The Cu²⁺ ions are in well-defined axial sites but subjected to small distortion leading to the broadening of the spectra. The spin-Hamiltonian parameter values indicate that the ground state of Cu²⁺ is d _{x2 y2} and the site symmetry around Cu²⁺ ions is tetragonally distorted octahedral. The optical absorption spectra exhibited a broad band corresponding to the d-d transition bands of Cu²⁺ ion. By correlating EPR and optical absorption data, the bond parameters are evaluated from various techniques.

The oxide glasses MoO₃-PbO-B₂O₃:V₂O₅ have been investigated by the standard melt-quenching technique. The amorphous nature of studied glasses is ascertained by X- ray diffraction patterns. Electron paramagnetic resonance (EPR) of these glasses has been studied. The hyperfine coupling parameter (P) decreases with an increase in MoO₃ content. The increase in the value of the Fermi contact interaction term (K) with an increase in MoO₃ content is due to an increase in the tetragonality of the V⁴⁺O₆ complex.

Glasses of the system: xB₂O₃-10Bi₂O₃-30Li₂O-xPr₆O₁₁ where x =1, 1.5 and 2 were prepared by melt quenching technique. Optical absorption and emission spectra have been recorded. The intensities of f-f transition are calculated in term of Judd-Ofelt (JO) intensity parameters Ω_λ (λ = 2, 4 and 6). Using the fluorescence data and these Ω_λ parameters, various radiative properties like transition probability (A_rad), branching ratio (β_R), radiative lifetime (τ_R), and stimulated emission cross section (σ_p), of various emission lines have been evaluated. The branching ratio for ³P₀→³H₄ transition is 56% and the predicted spontaneous radiative transition probability rates are fairly high 16411 s⁻¹. This is beneficial for lasing emission.

Different forms of calcium-phosphate (Hydoxyapatite, α-TCP, β-TCP, CDHA) minerals are found to be major component of bone tissue. Development of calcium-phosphate (CaP) based fibrous microstructures is of significant research interest worldwide owing to its improved mechanical properties and higher interconnectivity. Here we represent a method for single step sintered wet-spun Fibers of calcium phosphate from avian egg shells for biomedical applications.

Raw egg shell powder was mixed with chitosan solution and Phosphoric acid. The mixture is milled in a ball mill overnight and then filtered. The slurry was de-aired using 100 microliter 1-octanol per 100 ml of slurry as antifoaming and wet spun in coagulation bath. Fiber was dried overnight and sintered at different temperatures for microstructure and phase analysis. Both green and sintered Fibers were physico-chemical characterized by SEM, EDX, XRD, TGA, DSC, FTIR, and stereo-zoom microscopy. The fibers obtained in this procedure are found to have highly porous interconnected structures which can provide good cell adhesion and therefore can be used for bioactive scaffold making.

The paper undertakes the preparation of Aluminium oxide doped Lithium borate glasses and characterizes to investigate the physical and optical studies of these glasses using density and UV-Visible spectroscopy. Results had been obtained with the help of FTIR Spectra in our previous work which indicate that Al₂O₃ acts as a network modifier by converting three coordinated boron atoms [BO₃] to four coordinated boron atoms [BO₄]. The effect of aluminium content on the optical properties of the present glass system has been studied from the optical absorption spectra. It shows the shifting of the band edge towards the higher wavelength and that there is corresponding decrease in the band gap, which is due to the conversion of BO₃ to BO₄ units. The evaluation of the compact structure of prepared glass samples with the presence of [BO₄] groups has been made in terms of the physical properties such as density and molar volume. It is also confirmed by average boron-boron separation results. The research findings confirm that the addition of Aluminium oxide increases the covalent value and corresponding decrease in ionicity behaviour.

Metallic glasses have received considerable attention in comparison to normal metallic materials due to their superior physical, mechanical, electrical and magnetic properties. Understanding the glass transition kinetics of metallic alloys is of great importance in order to know its thermal stability. In the present paper, kinetics of glass transition of metallic glass Co₆₆Si₁₂B₁₆Fe₄Mo₂ is studied using thermal analysis technique, i.e. differential scanning calorimetry (DSC), by non-isothermal heating of the sample at four different heating rates. The activation energy (E) of the glass transition region is determined by two most frequently used methods, namely, Moynihan’s method and Kissinger’s equation. The fragility index, m is also calculated using T_g, which is a measure of glass forming ability of the given system. The results show that the fragility index ‘m’ of the given system falls below 16. This clearly indicates that the given system is strong liquid with excellent glass forming ability (GFA).

Knowledge of Glass forming Ability (GFA) of metallic glasses is of great importance as it gives an insight of a better Glass former. Number of GFA parameters like Gibb’s free energy difference ∆G, ∆S, ∆H, η, γ, γ_m, Q, T_rg (=T_g/T_l) etc. are calculated and compared for Mg-Ni-Pr-based metallic glass forming alloys to predict which parameter describes the best GFA criterion. On the basis of these parameters the excellent glass forming composition is identified. Also the GFA parameters of Mg-Ni-Pr-based alloys are studied in air and argon atmosphere. Present work suggests that ∆G is the best GFA criterion and Mg-Ni-Pr-based metallic glassy alloys can be successfully fabricated in air due to its high oxidation resistance ability.

Cobalt doped Titanium Dioxide (TiO₂) were synthesized by a standard solid-state reaction method. The dielectric constant and loss have been measured as a function of frequency (100 Hz-1 KHz) and temperature (50°C to 300°C). Similar behavior is observed between dielectric constant and dielectric loss. Both dielectric constant and dielectric loss are found to decrease with increasing frequency. Photoluminescence (PL) spectra were taken at different excitation wavelength. PL emission spectra shows a broad spectra in the range 400 nm to 500 nm.

In the present study, Strontium doped Titanium Dioxide (TiO₂) were synthesized by standard solid-state reaction technique. The dielectric property of the synthesized samples has been studied in the present work. The dielectric constant and loss have been measured as a function of frequency (100 Hz-1 KHz) and temperature (50°C to 300°C). Strontium doped TiO₂ shows interesting optical properties promising a variety of optical applications. Photoluminescence (PL) spectra was obtained at different excitation wavelength. PL emission spectra show that positions of PL peaks gradually shifts towards the violet region with increase of Sr ion dosage from 3% to 5%. The results are discussed in details.

We have performed ab-initio investigation of SrTiO₃ with cubic structure, and have computed its structural and electronic properties. The calculations are performed using a plane wave expansion within the local density approximation and the pseudopotential approximation. Results are given for the lattice constant, bulk modulus and charge density. The lattice parameter and bulk modulus calculated for SrTiO₃within LDA are 3.908 Å and 184.6832 GPa respectively. It is found that the calculated lattice parameter and bulk modulus are in good agreement with the available experimental data. The charge density plots show higher accumulation of charge around the boundary and corners. All these calculations have been carried out using ABINIT computer code.

CdSe is an important II-VI, n-type direct band gap semiconductor with wide band gap (bulk band gap of 2.6 eV) and an attractive host for the development of doped nanoparticles. Poly vinyl alcohol (PVA) is used as a capping agent to stabilize the CdSe nanoparticles. The optical properties of Co (II) ion doped PVA capped CdSe nanoparticles grown at room temperature are studied in the wavelength region of 200-1400 nm. The spectrum of Co (II) ion doped PVA capped CdSe nanoparticles exhibit five bands at 1185, 620, 602, 548 and 465 nm (8437, 16125, 16607, 18243 and 21499 cm^-1). The bands observed at 1185, 548 and 465 nm are correspond to the three spin allowed transitions ⁴T_1g (F) → ⁴T_2g (F), ⁴T_1g (F) → ⁴A_2g (F) and ⁴T_1g (F) → ⁴T_1g (P) respectively. The other bands observed at 602 nm and 620 nm are assigned to spin forbidden transitions ⁴T_1g (F) → ²T_2g (G), ⁴T_1g (F) → ²T_1g (G). The small value of the Urbach energy indicates greater stability of the prepared sample.

We investigated the effect of Ni doping on the structural and electrical properties of LaCoO₃. Single phase LaCo_1-xNi_xO₃ (x = 0, 0.1, 0.3, 0.5) were synthesized using solid state reaction method. Space group, lattice constants and atomic positions were determined by Rietveld refinement of powder diffraction data. The unit cell parameters found to increase with Ni doping. Four-probe direct current conductivity measurements were also carried out to investigate transport behavior of compounds. Samples were found to exhibit temperature dependent semiconducting behavior. The drastic improvement of the room-temperature conductivity of doped samples with respect to the pure compound has been observed and explained in terms of decrease in band gap. The transport mechanism in different regions of temperature has been investigated by fitting Arrhenius and variable range hopping (VRH) models.

Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma. Usually, laser ablation refers to removing material with a pulsed laser, but it is possible to ablate material with a continuous wave laser beam if the laser intensity is high enough. In general, the method of pulsed laser deposition (PLD) is simple. Only few parameters need to be controlled during the process. Targets used in PLD are small compared with other targets used in other sputtering techniques. It is quite easy to produce multi-layer film composed of two or more materials. Besides, by controlling the number of pulses, a fine control of film thickness can be achieved. Pulsed-laser deposition has been used to deposit an extraordinarily wide range of materials. Historically, the most significant application of PLD has been in the area of high temperature superconducting thin films. The demonstration that PLD could be used to deposit YBa₂Cu₃O_7-x (YBCO) films with zero resistivity at nearly 85 K sparked a significant amount of high temperature superconductivity research over the past decade and has stimulated research in PLD in general. The most striking limitations of PLD are the generation of particulates during the deposition process and the non uniform coating thickness, when substrates of large area are deposited.

A series of Nano MgAl_2-2xY_2xO₄ (x = 0.00, 0.07 & 0.10) was prepared by chemical co-precipitation technique. X-ray diffraction (XRD) analysis reveals that a secondary phase appears at x = 0.10 along with the spinel phase. The broad peaks in the XRD pattern and particle size analysis by Transmission electron microscopy (TEM) confirmed nanocrystalline nature of the samples. Room temperature dielectric response as a function of frequency (1 kHz to 1MHz) shows that dielectric constant loss tangent and ac conductivity decreases with increase in yttrium content. The variation of dielectric constant as a function of frequency indicates the dielectric dispersion due to Maxwell-Wagner Polarization. The variation of AC conductivity with frequency suggests the conduction mechanism due to small polaron hopping.

In this paper, we report on the thermoluminescence response of nanocrystalline co-doped alkaline earth aluminates synthesized by combustion method using metal nitrate as precursor and urea as fuel. A broad TL glow peak was observed at 367 K with a shoulder at 400K. TL Anal program has been used for GCD curve fitting. The Kinetic parameters like, the activation energy (E_α), the frequency factor (s) and the order of kinetics were calculated for the SrAl₂O₄: Eu²⁺, Dy³⁺nanophosphors. The best dopants combination was Eu (1 mol%) and Dy (2 mol%). The samples were irradiated with γ-dose in the range 20Gy–800Gy, at room temperature. A shift from 367 K to 376 K was also observed in the main peak with an increase in irradiation dose which suggest that the irradiation doses affect the distributions of traps produced by the gamma-ray irradiations. Kinetic parameters also suggest that TL glow curve in SrAl₂O₄: Eu²⁺, Dy³⁺ nanophosphors is obeying second order kinetics. The nanophosphors show linear response with dose.

Sodium (50%) mixed layered Li₂Ti₃O₇ and its 0.01, 0.05 & 1.0 molar percentage CuO doped derivatives have been prepared through high temperature solid state reaction and characterized through X- ray diffractometer, d.c. conductivity in the temperature range 373–700K and room temperature EPR investigation. Room temperature X-ray diffratograms confirm the phase evolution. Room temperature electron paramagnetic resonance (EPR) data show that Cu²⁺ occupies Ti⁴⁺ lattice sites giving rise to electric dipoles which increases electric permittivity. The absorption peak in EPR spectra gets broadened due to increased exchange interaction in heavily doped derivatives. Four distinct regions have been identified in the Ln(σT) versus 1000/T plots. Various electrical conduction mechanisms have involved during the whole temperature range of study

Graphene/Y₂O₃ quantum dots (QDs) composite was investigated towards the carbon dioxide (CO₂) gas at room temperature. Graphene synthesized by electrochemical exfoliation of graphite. The composite prepared by mixing 20-wt% graphene into the 1 g Y₂O₃ in organic medium (acetone). The chemiresistor of composite prepared by screen-printing on glass substrate. The optimum value of sensing response (1.08) was showed by 20-wt% graphene/Y₂O₃ QDs composite. The excellent stability with optimum sensing response evidenced for the composite. The gas sensing mechanism discussed on the basis of electron transfer reaction.

In order to move towards a sustainable existence in our critically energy dependent society there is a continuing need to adopt environmentally sustainable methods for energy production, storage and conversion. A fuel cell is an energy conversion device that generates electricity and heat by electrochemically combining a gaseous fuel and an oxidant gas through electrodes and across an ion conducting electrolyte. The use of fuel cells in both stationary and mobile power applications can offer significant advantages for the sustainable conversion of energy. Currently the cost of fuel cell systems is greater than that of similar, already available products, mainly because of small scale production and the lack of economies of scale. The best fuel for fuel cells is hydrogen and another barrier is fuel flexibility. Benefits arising from the use of fuel cells include efficiency and reliability, as well as economy, unique operating characteristics and planning flexibility and future development potential. By integrating the application of fuel cells, in series with renewable energy storage and production methods, sustainable energy requirements may be realized. As fuel cell application increases and improved fuel storage methods and handlings are developed, it is expected that the costs associated with fuel cell systems will fall dramatically in the future.

We have investigated the thermal and allied properties of Tb_0.5Sr_0.5CoO₃ for the temperature range 1K≤T≤300K using the Modified Rigid Ion Model (MRIM). The calculated bulk modulus, specific heat, and other thermodynamic properties obtained from MRIM have presented proper interpretation of the experimental data, for Sr ions doped TbCoO₃. In addition, the results on the cohesive energy (φ), Debye temperature (θ_D) and Gruneisen parameter (γ) are also discussed.

A simple and straightforward theoretical model is developed to investigate the elastic constants of alkaline earth oxide solids under the effect of temperature. The calculation are performed with the help of high temperature equation of state (EOS) derived from Tallon's method based on thermodynamic analysis. The results obtained for these solids are discussed and compared with experimental data under the effect of high temperature. The results are found to be in good agreement with available experimental results

The polycrystalline sample of SrB₄O₇ doped with copper was prepared by employing the combustion synthesis and studied for its thermo luminescence properties when exposed to Gamma-rays. The Kinetic parameters were calculated using peak shape method. The effect of dose Variation and concentration of copper on SrB₄O₇ phosphor were also studied.

Glasses having composition 20CdOxBi₂O₃(79.5-x)B₂O₃0.5Pr₆O₁₁ with x varying from 15 to 35 mol% have been synthesized. Optical absorption and fluorescence spectra were measured at ambient temperature. A close correlation is observed between the Bi₂O₃ content and the spectroscopic properties such as Judd-Ofelt intensity parameters Ω_λ = (λ = 2, 4, 6), radiative and structural properties of prepared glasses doped with Pr³⁺ ion. The variation of Ω₂ with Bi₂O₃ content has been attributed to changes in the asymmetry of the ligand field at the rare earth (RE) ion site (due to structural change) and to changes in RE-O covalency, whereas the variation of Ω₆ has been related to the variation in RE-O covalency. Following the luminescence spectra, various radiative properties like transition probability (A_rad), radiative lifetime (τ_r), branching ratio (β_r) and stimulated emission cross section (σ) have been calculated. The branching ratio for ³P₀ → ³F₂ transition of Pr³⁺ glass system arrive at 41 to 40%, respectively, and the predicted spontaneous radiative transition probability rates are high and varies from 14032 to 14864 s⁻¹. In addition, the glass stability is improved in which the substitution of B₂O₃ for Bi₂O₃ strengthens the glass network structure. The bismuth based glass as a host for Pr³⁺ ion doped suggesting their suitability for laser applications.

The present paper reports abrasive wear behaviour of copper matrix composites reinforced with silicon carbide and silica particles. Copper – SiC (12%) and Copper-SiO₂ (9%) composites were prepared by powder metallurgical technique. Metallography, image analysis and hardness studies were carried out on copper composites. The abrasive wear experiments were carried out using pin on disc apparatus. The effect of sliding distance and load was studied on Copper – SiC (12%) and Copper-SiO₂ (9%) composites. The abrasive wear volume loss increased with sliding distance in both the composites although the magnitude of increase was different in each case. Copper – SiC (12%) composites exhibited relatively better abrasion resistance as compared to and Copper-SiO₂ (9%) composites. The abraded surfaces were observed under scanning electron microscope to study the morphology of abraded surfaces and operating wear mechanism. The analysis of wear debris particles was also carried out to substantiate the findings of the investigation.

Glasses with composition 20B₂O₃.(79.5-x)Bi₂O₃.xSiO₂ (10 ≤ x ≤ 40) containing 0.5mol% of Er³⁺ ions were prepared by melt-quench technique. Optical absorption and fluorescence spectra were recorded at room temperature for all glass samples. Based on the Judd-Offelt theory, spectroscopic properties of Er³⁺ ions are discussed by changing the host glass compositions. The intensity parameters Ω₂, Ω₄, and Ω₆ are determined by applying least square analysis method. The variation of Ω₂ and Ω₆ with Bi₂O₃ content has been attributed to changes in the asymmetry of the ligand field at the rare earth ion site and to the changes in the rare earth oxygen (RE-O) covalency. The variation of Ω₄ with Bi₂O₃ content has been attributed to rigidity of the samples. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross-section of various emission lines have been evaluated. An intense green luminescence bands with maximum around 516 nm and 536 nm are assigned to the ²H_11/2→ ⁴I_15/2 and ⁴S_3/2→ ₄I_15/2 transitions respectively has been obtained.

The optical absorption spectra of complex of Praseodymium in different solvents i.e water, Methanol, Ethanol & Acetic Acid have been recorded in visible region (360-620 nm for Pr³⁺) using amino acid as primary ligand and diol as secondary ligand. The value of energies & intensities of various transitions have been calculated using Judd-Ofelt relation is in good agreement with experimental result. The study of complex found it to be covalent in nature. The spectra in visible region have been recorded on model uv-2601 Rayleigh analytical instrument corp.

Bulk samples of Te-rich Ge20Te80-xBix (x = 0, 1.5, 2.5, 5.0) glassy alloys are prepared by melt quenching technique. The thin films of the bulk samples are deposited by using vacuum evaporation technique for their electrical and photoelectrical measurements. Keithley 6487 picoammeter has been used to study the electrical and photoelectrical characteristics of Ge20Te80-XBix thin films kept in vacuum. Temperature dependent dark and photoconductivity is studied in the temperature range 300-360 K and voltage V = 80V. Photoconductivity with intensity at room temperature follows a power law where power γ lies near to 0.5, suggesting that the recombination is bimolecular in nature. The density of defect states and photosensitivity are found to follow an opposite trend with each other. The differential life time is determined from the rise and decay of photocurrent w.r.t. time. The dispersion parameter and localized state distribution parameter are estimated from decay curves and reported for the studied composition.

Pure and 4.5 wt% Zn- doped SnO₂ nanopowders were synthesized by sol-gel method. These nanopowders were characterized by X- ray diffraction, Scanning electron microscopy, UV-Vis spectroscopy, I-V measurements and R-T measurements. XRD results confirmed the formation of tetragonal rutile type SnO₂ with the average crystallite size of 14 ± 1 nm which decreased to 9 ± 1 nm with 4.5 wt% Zn addition. Increase in band gap is observed from UV-Vis spectroscopy. Electrical characterizations revealed increase in resistivity with Zn addition. Temperature dependent resistance measurement showed that both the pure and the Zn- doped samples are suitable for gas sensing applications. A detailed study of these synthesized nanostructured samples is presented and discussed in the paper.

The paper presents the study of thermo gravimetric and differential thermal analysis of blended clay. Western part of Rajasthan (India) is rich resource of Ball clays and it is mainly used by porcelain, sanitary ware, and tile industry. The quality and grade of clay available in the region vary from one deposit to other. To upgrade the fired colour and strength properties, different variety of clays may be blended together. The paper compares the results of thermal analysis one of blended clay B2 with reference clay of Ukraine which is imported by industries owners. The result revealed that the blended clay is having mineral kaolinite while the Ukrainian clay is Halloysite.

Dielectric behaviour of Nanocrystalline CaFe₂O₄ ferrite synthesized by advanced sol- gel method has been investigated as a function of frequency at different temperatures. Rietveld profile refinement of the XRD pattern confirms formation of cubic spinel structure of the specimen.The dispersion in dielectric behavior of CaFe₂O₄ferrite sample has been observed in the temperature range of 100-250˚C as a function of frequency in the range 75 kHz to 10 MHz Both the real value of dielectric constant (ɛ′) and the dielectric loss factor (tanδ) decrease with frequency. This decrease in the values of ɛ′ and tanδ could be explained on the basis of available ferrous, i.e. Fe²⁺, ions on octahedral sites such that beyond a certain frequency of applied electric field the electronic exchange between the ferrous and ferric ions i.e. Fe²⁺↔Fe³⁺ cannot follow the applied alternating electric field.

In the present paper, we have investigated the solitonic characteristics of a pulse passing through an interface separating two nonlinear media. The first media is a thin film of gallium nanoparticles which show switching properties under optical excitation and second is a monomode optical fiber. Soliton propagation in three different phases of gallium nanoparticles have been analyzed by using the method of phase-plane analysis. Also, the critical power required for soliton propagation has been calculated.

CNT-ZnO nanocomposite powders were synthesized by addition of carbon nanotubes (CNT) during the growth of ZnO nanoparticles using a wet-chemical method. These CNT-ZnO nanocomposites powder were then spin coated on corning glass substrates to obtain thin films which were characterized using X-ray diffraction, scanning electron microscopy and current voltage characteristics. Hydrogen sensing (50- 1000 ppm) carried out on pure and CNT-ZnO nanocomposites at operating temperature of 250 and 300°C in N₂ atmosphere (0.4±0.03 mbar) revealed higher sensitivity in 2 wt.% CNT-ZnO nanocomposite thin film compared to the pure ZnO thin film.

A high-temperature solid-state reaction technique was used to prepare polycrystalline samples of electrocerimic, lead zirconate titanate (PZT) modified by manganese (Mn) with Zr/Ti ratio of 65/35 (i.e., Pb(Zr_0.65-xMn_xTi_0.35)O₃ (x = 0, 0.02, 0.06, 0.10)). Preliminary structural analysis by an X-ray diffraction (XRD) technique has confirmed the formation of compounds with no pyrochlore phase. The XRD patterns clearly show that there is no major structural change of Pb(Zr_0.65-xMn_xTi_0.35)O₃ on substitution of Mn at the Zr-site. Although at higher (x=0.10) modification some small satellite peaks do appear. The micro-structural analysis of the surface of the compounds by scanning electron microscopy (SEM) suggests that the grains are uniformly and densely distributed over the entire surface of all the samples and are spherical in all the cases. Room temperature variation of ε_r and tanδ as a function of frequency shows that ε_r and tanδ decreases with rise in frequency, which is a general feature of normal ferroelectric material’s dielectric properties, irrespective of composition of the specimens. The higher value of ε_r at lower frequencies is due to simultaneous presence of all types of polarizations (i.e., interfacial, ionic, dipolar, electronic, space charge, etc.) in the compounds. Detailed studies of the dielectric properties reveal that the compounds showed (i) shift in T_c, and (ii) improvement in dielectric constant and loss.

The Phase transition and elastic properties of Praseodymium-monopnictides have been investigated under pressure by means of a modified charge-transfer potential model which incorporates the Coulomb screening due to the delocalization of f-electron of rare-earth atom leading to many-body interactions, along with Coulomb interaction, covalency effect and overlap repulsion extended up to second-nearest neighbours. These compunds undergo transition from NaCl structure to high pressure body-centered tetragonal (BCT) structure (distorted CsCl-type P4/mmm). The calculated values of cohesive energy, lattice constant, phase transition pressure, relative volume collapse. Present model explains the Cauchy’s discrepancy correctly.

Doping of non-interacting nanoparticles in YBCO superconductors in order to get fine microstructure defects has been studied. Y-211 inclusion, itself has large potential to create structural defects without affecting Y-123 matrix phase. Nanoparticles of grain refining agent like CeO₂/Pt/PtO₂ are interesting dopants, especially CeO₂ for being cheaper than Pt. POIG process, as is one of the advance processing techniques to get uniform distribution of fine Y-211 particles of the order of 1-2 μm, throughout the YBCO composites. Finer Y-211 particles can drastically increase the pinning centers. Introduction of fine sized CeO₂ as grain refining agent to reduce the size of Y-211 particles would create additional pinning centers. In the present work, the effect of CeO₂ on Y-211size and distribution in POIG processed YBCO composite was studied. It was observed that with increase in CeO₂ content Y-211 particle size decreases below 1μm and even less than 0.5μm for 10 weight percent CeO₂ doping. The mechanism for refinement appears to be the formation of BaCeO₃ on the surface of Y-211 during liquid phase infiltration that leads to splitting of Y-211 into smaller particles.

ZnO powder was synthesized by solid state reaction method. The synthesized powder was granulated and pressed using uni-axial press for preparing the pallets. The prepared pellets were sintered in conventional furnace at different temperatures (900-1300° C). The phase study was done by powder X-ray diffraction and it was found that the there is no other phase present in the synthesized material but the peak intensity is increasing with temperature. The crystallite size of the synthesized ZnO powder was found to be increase with temperature. The effect of sintering on grain growth is investigated by scanning electron microscopy (SEM). SEM revels that the average grain size is increases with increase in sintering temperature. AC impedance of these samples was decreased markedly with increased sintering temperature. In present work the effect of sintering temperatures and hold time on micro structural and electrical properties of ZnO ceramics is carried out.

The Systematic investigation of structural behaviour of GdMn_1-xCr_xO₃ (x=0, 0.1, 0.2) has been undertaken which are synthesized by conventional solid state reaction method. All the XRD reflection lines were successfully indexed according to orthorhombic perovskite structure with space group: pbnm (62). Upon chromium (Cr) doping on the Mn site the unit cell volume has reduced due to slight difference between the ionic radii of Cr³⁺ and Mn³⁺ compare with Pure GdMnO₃. The relation between lattice parameter infer that all the samples have O´ type orthorhombic structure which is highly distorted perovskite structure but increasing the Cr concentration the orthorhombic distortion decrease that deduce the non John Teller nature of these samples.

LiFePO₄ has become of great interest as storage cathodes for rechargeable lithium batteries because of their high energy density, low raw materials cost, environmental friendliness, high thermal stability. In the present investigation, lithium iron phosphate (LiFePO₄) cathode material has been prepared by using hydrothermal synthesis. The structure of the sample has been studies by using X-ray diffraction. The XRD spectrum exhibited different characteristic peaks along with (311) predominant orientation corresponding to an orthorhombic crystal structure with Pnma space group. Electrical and dielectric properties were studied over a frequency range of 1 Hz – 1 MHz at different temperatures. The electrical conductivity was found to be increased with increasing temperature following Arrhenius relation with an estimated activation energy of 0.44 eV. The dielectric properties were analyzed in the framework of complex dielectric permittivity and complex electric modulus formalisms. The evolution of the complex permittivity as a function of frequency and temperature was investigated. Several important parameters such as activation energy, ionic hopping frequency, carrier concentration, ionic mobility and diffusion coefficient etc, were determined.

In this paper we have studied the variation of normalized per-atom pair cohesive (binding) energy and melting temperature with size and number of atom-pairs in the BN nano-crystal by simple model approach. In small nano-particles, large proportions of their atoms reside either at or near the surface, and those in clusters are basically all on the surface. So, we have to study the surface configuration in detail that leads the constancy of the crystals. Even for bulk materials, parameters that ensure this constancy involving normalized cohesive energy, surface reconstruction, iconicity, bulk structure, hybridization and charge balance, melting point. It is worthwhile to say that many of these factors are quite interdependent. These all factors influence the whole cohesive energy of crystals and give important information about the deflections from inverse size dependence. The per-atom-pair binding energy and melting temperature of BN nano-crystal is a quadratic function of the inverse of the crystal size. The binding energy and melting temperature comes near their bulk value with increasing the crystal size and same as the bulk material when the crystal size is above than 100 nm.

The structural and thermodynamic properties of polycrystalline samples of Y_0.5Dy_0.5MnO₃ were investigated in order to investigate the effect of higher magnetic moment ion over Y ion. The structural transition from hexagonal to orthorhombic is observed at very high doping of Dy ion. Heat capacity measurements were performed at 2-300K in the application of different high magnetic field and the transition indicates the spin alignment of Mn³⁺(T_N^Mn3+). By using heat capacity data also calculated Debye temperature of the series.

Nanopowders of Ce_0.8Y_0.2O₂ were prepared by sol-gel via hydrolysis method for different hours. The prepared powders are characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and analyzed by UV-visible spectroscopy, Photoluminescence (PL) and Energy dispersive X-ray analysis (EDAX). Cubic fluorite structure of the prepared samples was confirmed by powder X-ray diffraction and the grain size of the prepared samples in the range of 12 to 33 nm. The functional groups of the prepared nanopowders are identified by FTIR spectra. The band gap energy obtained from the UV spectra. From the photoluminescence spectra, there is a mirror image relation between absorption and emission spectra. The purity of the prepared samples is confirmed by EDAX measurements.

Nanostructured zinc oxide overlayered by nanoporous strontium titanate was synthesized using sol-gel method and tested in a photoelectrochemical (PEC) cell for splitting of water. It was found that compared to the pristine ZnO and SrTiO₃, the resistivity of bilayered thin film was reduced and a negative shift in open circuit potential and flatband potential of bilayered ZnO/SrTiO₃ was observed, thus improving the photocurrent density and photoconversion efficiency. Significantly, bilayered ZnO/SrTiO₃ thin film offered the best photocurrent density i.e. 0.46 mA/cm² at 0 V/SCE. XRD, SEM and UV-Vis spectroscopic studies were carried out to explore the structural, surface morphological and optical properties of various thin films.

Polymer composites have emerged as a new class of materials, which have attracted technologist as they display novel properties compared to traditional materials and dramatically improves the performance properties of polymer system. We have synthesized hexaferrite-polymer composites of Polyvinylidene Fluride (PVDF) with BaCa₂Fe₁₆O₂₇ (2.0, 5.0 % wt/vol.) using a melt compounding technique. BaCa₂Fe₁₆O₂₇ hexaferrite powder was prepared using a microemulsion technique and directly mixed in melted PVDF, following by a low temperature hot pressing. The composites of PVDF with various weight percent of BaCa₂Fe₁₆O₂₇ (2.0 & 5.0% wt/vol.) were processed via melt mixing at 200°C, with 60 rpm for 5 minutes. The films of uniform thickness are about 0.5 mm is obtained by a compression molded instrument at 200°C under 5-ton pressure. The influence of BaCa₂Fe₁₆O₂₇ hexaferrite contents on magnetic and dielectric properties of composite was investigated. The prepared PVDF- BaCa₂Fe₁₆O₂₇ composite thick films were characterized for their magnetic; dielectric and thermal behavior employing magnetic, dielectric and thermal analysis (TGA/DTA). Maximum saturation magnetization was obtained for 5 % wt/vol. of barium calcium hexaferrite composite.

Synthesis and characterization of Cobalt ferrite powders by a sol gel combustion process is focused in the present work. The prepared precursors was calcined at 950° C for 4 hours in order to get cobalt ferrite powder. The effect of metal nitrates/citric acid ratio (referred as x) of CoFe₂O₄ on structural and micro-structural properties was investigated. The structural characterization on CoFe₂O₄ ferrite samples were carried out using the X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques. Phase identification and crystallite size of calcined powder were determined using XRD analysis. The formation of the ferrite is confirmed by FTIR results. The morphology of prepared CoFe₂O₄ ferrite samples (with x = 0.5, 1.0, 1.5 and 2.0, where x is metal to citrate ratio) was studied using a scanning electron microscopy.

Down scaling of complementary metal oxide semiconductor transistors has put limitations on silicon dioxide to be used as an effective dielectric. It is necessary to replace the SiO₂ with a physically thicker layer of oxides of high dielectric constant. Thus high k dielectrics are used to suppress the existing challenges for CMOS scaling. Many new oxides are being evaluated as gate dielectrics such as Ta₂O₅, HfO₂, ZrO2, La₂O₃, HfO₂, TiO₂, Al₂O₃, Y₂O₃ etc but it was soon found that these oxides in many respects have inferior electronic properties to SiO₂. But the the choice alone of suitable metal oxide with high dielectric constant is not sufficient to overcome the scaling challenges. The various deposition techniques and the conditions under which the thin films are deposited plays important role in deciding the structural and electrical properties of the deposited films. This paper discusses in brief the various deposition conditions which are employed to improve the structural and electrical properties of the deposited films.

In this paper, we consider a parametrically driven discrete nonlinear Schrödinger equation. Analytical and numerical calculations are performed to determine the existence and stability of fundamental bright discrete solitons admitted by discrete nonlinear Schrödinger equation. We show that a parametric driving can destabilizes onsite bright solitons and stabilizes intersite bright discrete solitons. Stability windows of all the fundamental solitons are presented and approximations to the onset of instability are derived using perturbation theory, with accompanying numerical results.

Thin film materials are the key elements of continued technological advances made in the fields of optoelectronic, photonic and magnetic devices. Thin film studies have directly or indirectly advanced many new areas of research in solid state physics and chemistry which are based on phenomena uniquely characteristic of the thickness, geometry and structure of the film. The processing of materials into thin films allows easy integration into various types of devices. Thin films are extremely thermally stable and reasonably hard, but they are fragile. On the other hand organic materials have reasonable thermal stability and are tough, but are soft. Thin film mechanical properties can be measured by tensile testing of freestanding films and by the micro beam cantilever deflection technique, but the easiest way is by means of nanoindentation. Optical experiments provide a good way of examining the properties of semiconductors. Particularly measuring the absorption coefficient for various energies gives information about the band gaps of the material. Thin film materials have been used in semiconductor devices, wireless communications, telecommunications, integrated circuits, rectifiers, transistors, solar cells, light-emitting diodes, photoconductors and light crystal displays, lithography, micro- electromechanical systems (MEMS) and multifunctional emerging coatings, as well as other emerging cutting technologies.

The polycrystalline YBa₂(Cu_1-XZn_X)₃O_7-δ samples (x=0.0 to 0.06) were synthesized and studied using X Ray diffraction, titration, resistivity, magnetization and X ray photoelectron spectroscopy (XPS). Results show that O₂ stoichiometry (δ) changes on Zn substitution which affects their normal state resistivity as well as the T_C. Zn also induces local magnetic moment as evidenced from magnetization results. A combination of change in O₂ stoichiometry and magnetic pair breaking is found to be responsible for a rapid suppression of superconductivity.

Cryogenics is the study of the production of very low temperature (below −150°C, −238°F or 123K) and the behavior of materials at those temperatures. Similarly, cryogenic grinding is a term supported by the act of grinding a thing at very low temperature. This technique is generally used to grind the material, which contains heat labile constituents viz- volatile oils in seed spices. Due to high fat content in spices, heat is generated, while energy is used to fracture a particle into a smaller size in conventional grinding process. During the normal grinding process, this generated heat causes temperature rise of grinder upto 95⁰C. The increased temperature is responsible for a loss of volatile content in the tune of about 30% and also produces dark colour powder.

Generally, continuous operation is not possible in normal grinding process due to melting of fat and sticking of powder on the grinding surface. The loss of volatile content can be significantly reduced by cryogenic grinding technique using liquid nitrogen or liquid carbon dioxide that provides the refrigeration needed to pre-cool the spices and maintain the desired low temperature by absorbing the heat generated during the grinding operation. The extremely low temperature during grinder condenses the volatile matter and retains their presence in spices. The application of cryogenic technology for grinding of spices has been scientifically proved to be a suitable technique with negligible loss of volatile content and improved colour of oil and grinding operation of seeds.

Bianchi Type VI₀ inflationary cosmological model with flat potential in General Relativity, is investigated. To get the deterministic solution in terms of cosmic time t, we assume that σ (shear) is proportional to expansion (θ) where Thus , leads to A = Bⁿ where A and B are metric potentials and n is a constant. We find that spatial volume increases with time. Hence inflationary scenario exists in the model. Since in general. Thus the model represents anisotropic universe throughout. However, if then the model isotropizes. This result matches with astronomical observations. The model represents decelerating and late time acceleration which matches with recent astronomical observations Riess et al. [29], Perlmutter et al. [30]. The model has Point Type singularity at (MacCallum [31]). The rate of Higg’s field (φ) decreases with time.

The paper has been designed to make a comprehensive review of a particular series of organic molecular assembly in the form of compendium. An overview of general description of fifteen quinoline derivatives has been given. The biological activity spectra of quinoline derivatives have been correlated on structure activity relationships base which provides the different P_a (possibility of activity) and P_i (possibility of inactivity) values. Expositions of the role of intermolecular interactions in the identified derivatives have been discussed with the standard distance and angle cut-off criteria criteria as proposed by Desiraju and Steiner (1999) in an International monogram on crystallography. Distance-angle scatter plots for intermolecular interactions are presented for a better understanding of the packing interactions which exist in quinoline derivatives.

ab-initio calculations using fully relativistic pseudo-potential have been performed to investigate the high pressure phase transition, elastic and electronic properties of lead-chalcogenides including the less known lead polonium. The calculated ground state parameters, for the rock-salt structure show good agreement with the experimental data. The enthalpy calculations show that these materials undergo a first-order phase transition from rock-salt to CsCl structure at 19.4, 15.5, 11.5 and 7.3 GPa for PbS, PbSe, PbTe and PbPo, respectively. Present calculations successfully predicted the location of the band gap at L-point of Brillouin zone as well as the value of the band gap in every case at ambient pressure. It is observed that unlike other lead-chalcogenides, PbPo is semi-metal at ambient pressure. The pressure variation of the energy gap indicates that these materials metalized under high pressures. For this purpose, the electronic structure of these materials has also been computed in parent as well as in high pressure phase.

A study on the adsorption of copper (II) ions from the aqueous solution on waste wool had been carried out to analyze the adsorption capacity of waste wool, thereby aiming towards mitigation of metal ion pollution in industrial waste water. The effect of varying concentration of copper ions and varying time period, was studied on fixed weight of waste wool. The initial and final concentration of copper ions was measured by conductometric and spectrophotometric methods. Adsorption data were modeled with the langmuir and freundlich adsorption isotherms. The isotherm and first order equation were found to be applicable. Removal of metal ions using industrial waste wool is found to be favourable. Thus the work can be extended to study various physico-chemical parameters for removal of copper (II) ions from industrial effluents using waste wool. A later work can be involved where the waste wool adsorption parameter can be further utilized for composite ceramic products.

A single phase polycrystalline hexagonal YMn_0.8Ru_0.2O₃ compound with space group P6₃cm (25-1079) have been synthesized by using solid state reaction method at sintering temperature 1280°C. The detailed low temperature electrical properties were evaluated over a broad range of temperature. The temperature dependence of the dc resistivity at low temperature reveals the semiconducting behavior and favored the variable range hopping conduction model. The obtained experimental data in the temperature range of our study can be described by the equation ρ(T) = ρ₀exp[(T^*/T)^1/4]. The fitting results are used for the calculation of the ;temperature scale T^* ~ 1.05 × 10⁶K and finally the density of state at Fermi level N(E_F) is calculated to be ~ 5.6 × 10¹⁹ eV⁻¹ cm⁻³.

Undoped and Al-doped ZnO (AZO) nanoparticles (NPs) have been successfully synthesized by the simple sol-gel method. The NPs have been characterized by a number of techniques as x-ray diffraction (XRD), UV-visible spectroscopy and scanning electron microscopy (SEM) at room temperature for 0%, 0.5%, 1% and 2% of Al concentration. The structural characteristics were examined using XRD and SEM with EDS. XRD analysis reveals that all samples crystallizes in polycrystalline nature with wurtzite lattice and exhibit no other impurity phase. The average crystallite size decreases with increase in Al concentration. The absorption spectra indicate increase in optical energy gap (E_g) with increase in Al ion doped into the ZnO lattice site.

This paper demonstrates the alternative measures to generate the Steep wave impulse by using Impulse Voltage Generator (IVG) for high voltage testing of porcelain insulators. The modification of IVG by incorporating compensation of resistor, inductor, and capacitor has been achieved and further performance of the modified system has been analyzed by applying the generated lightning impulse and analyzing the electrical characteristics of impulse waves under standard lightning and fast rise multiple lightning waveform to determine the effect to improve rise time. The advantageous results have been received and being reported such as increase in overshoot compensation, increase in capacitive and inductive load ranges. Such further reduces the duration of oscillations of standard impulse voltages. The reduction in oscillation duration of steep front impulse voltages may be utilized in up gradation of Impulse Voltage Generator System. Stray capacitance could further be added in order to get the minimized difference of measurement between simulation and the field establishment.

The keyword for manufacturers of cutting tools and coatings for cutting tools is productivity: a 30%; reduction of tool costs, or a 50%; increase in tool lifetime results only in a 1%; reduction of manufacturing costs. But an increase in cutting data by 20%; reduces manufacturing costs by 15%;. In order to achieve higher productivity different approaches – High Performance Cutting (HPC) and High Speed Cutting (HSC) can be chosen. The performance of Carbide tools was studied to investigate the tool life and wear behavior at various machining parameters. This study presents tool wear characterization of carbide cutting tool inserts coated with titanium nitride (TiN) on a single point turning operation on copper, aluminum. A set of experiments with conditions of cutting speed, depth of cut and feed rate were performed on a lathe machine. Force analysis is done on Lathe Tool Dynamometer. From the result, cutting speed was found to be the main factor to have significant effect on surface roughness. At the end of this study, optimization was made by suggesting the most suitable sets of parameter settings to produce minimum surface roughness. Suggestion on parameter settings to obtain minimum surface roughness made.

We report here the structural and optical properties of Bi nanoparticles in polymer (polypyrrole) matrix. The nanoparticles are synthesized following a wet chemical route. The X-ray diffraction data clearly shows the growth of single crystalline Bi nanoparticles within the host polymer. The microstructure of the Bi nanoparticles obtained by transmission electron microscopy (TEM) reveals clearly the formation of spherical shaped nanoparticles of average size∼27 nm with a narrow size distribution. The optical absorption spectrum exhibits a distinct peak at 278 nm which is attributed to the surface plasmon band of Bi nanoparticles. The absorption spectrum is found to be described well following Mie theory.

The Tm(III) doped systems with various ligands studied with respect to hypersensitive transition. The spectroscopic data for hypersensitive transition have been correlated with the thermodynamic parameters. The thermodynamic parameters include thermodynamic efficiency and partition function of the transition.

A number of nanofluids have been prepared to study the effect of lubrication properties of nanofluids on stainless steels taking Kaolin and Boron Nitride (BN) as the lubricant particles and Sodium Dodecyl Sulfate (SDS), Cetyl Trimethyl Ammonium Bromide (CTAB), Sodium Hexa Meta Phosphate (SHMP) as dispersants in the same liquid medium i.e. water. A pin on disc tribometer is being used to access the tribological behaviour of the prepared nanofluids. The particle size of these particle dispersions are examined with a nanoparticle size analyzer. It has been found that the use of dispersants significantly control the particle size and tribological behavior of the nanofluids as for Boron Nitride particle with Sodium Dodecyl Sulfate (SDS) as dispersant has got a very low value of coefficient of friction being equal to 0.142 while without dispersant the value is 0.498. Similarly, in case of Kaolin water with SDS as dispersant the value of coefficient of friction obtained is 0.161 and without dispersant it is 0.333. Sodium Dodecyl Sulfate (SDS) as dispersant has resulted a very low coefficient of friction compared to other dispersants tested even though it doesn’t always assure a least particle size. The role of SDS in yielding the lowest friction has pursued significant attention for further investigation.

Depending on their strength, the electron–phonon interactions in systems involving electron moving in deformable lattice of atoms can become very important for the dynamics of such systems and may lead to some very interesting phenomena eg. quasiparicle self trapping. We consider Metallic Carbon Nanotube with an excess electron. We choose 2- dimensional hexagonal lattice to be periodic and to have a large extension in one direction and a small extension in the other direction. We study the Modified Nonlinear Schrodinger Equation in Carbon Nanotube (10,10) where the modified term arises due to interaction between excess electron field and lattice distortion and gives stabilization to the solution. This interaction symbolizes strength of nonlinearity in the system. We solved this equation numerically using cylindrical coordinates and found that solutions depend crucially on electron- phonon interaction coefficient.

Solitons are nonlinear waves that remain invariant as they propagate. Precise control of dispersion and nonlinear effects govern soliton propagation. In recent years Photonic crystals (PhCs) have attracted a great deal of attention due to the facility to engineer and enhance both their nonlinear and dispersive effects. In this article we show soliton pulse analysis in GaInP Photonic Crystal Waveguides using AUTO bifurcation analysis tool. We have demonstrated pulse compression at moderately slow velocities in GaInP Photonic Crystal Waveguides. This is enabled by the enhanced self phase modulation and strong negative group velocity dispersion in the Photonic Crystal Waveguides.

The aim of this research paper is to obtain a generalization of the following result involving product of generalized hypergeometric series due to Ramanujan.

The results derived in this paper are simple, interesting, easily established and useful from application point of view.

In the present paper, the nonlinear response of carbon nanotubes has been investigated by using the dielectric constants of these nanotubes evaluated by using the Maxwell-Garnett Effective Medium Theory. SWNT’s deposited on the tip of a dielectric substrate show a drastic change in reflectance and transmittance of the incident laser light due to change in their nonlinearity and optical constants. This property may be further used for developing all-optical switching devices.

A short-range force constant model has been applied in investigating the Raman and infrared modes in insulating Cs₂HgCl₄ in orthorhombic phase having space group Pnam using normal coordinate analysis. Calculations on zone centre phonons have been made with twelve stretching and three bending force constants. The calculated Raman and infrared wave numbers are in good agreement with the available experimental results. The potential energy distribution has also been investigated for determining the significance of contribution from each force constant towards the Raman and the infrared wave numbers.

LASER, an acronym for Light Amplification by Stimulated Emission of Radiation have unique properties, Which make it differ from ordinary light such as it is highly coherent, monochromatic, negligible divergence and scattering loss and a intense beam of electromagnetic radiation or light. It also occur in a wide range of wavelength/frequency (from Ultraviolet to Infrared), energy/power and beam-mode/configurations ; Due to these unique properties, it have use in wide application of ceramic processing for industrial manufacturing, fabrication of electronic circuit such as marking, serializing, engraving, cutting, micro-structuring because laser only produces localized heating, without any contact and thermal stress on the any part during processing. So there is no risk of fracturing that occurs during mechanical sawing and also reduce Cost of processing. The discussion in this paper highlight the application of laser in ceramics processing.

The aim of this research paper is to consider some very interesting reducible cases of H_A and H_C introduced by Srivastava who actually noticed the existence of three additional complete triple hypergeometric functions H_A, H_B and H_C of the second order in the course of an extensive investigation of Lauricella’s fourteen hypergeometric functions of three variables. The results are derived with the help of known classical summation theorems recently added in the literature due to Lavoie et al. Several results obtained earlier by Kim et al. follow special cases of our main findings.

In 1997, Exton have obtained an interesting case of the transformation of Kampé de Fériet function by employing classical Watson’s theorem on the sum of a ₃F₂.

The aim of this research note is to obtain one result contiguous to that of Exton.

The relativistic heavy ion collisions experiments are working on the different energies. In this paper we will study elliptic flow variation with pseudo rapidity at for charge pions and photons using HIJING event generator models. Elliptic flow is a signal in search of quark gluon plasma.

The relativistic heavy ion collisions are the experiment which is working on the different energies 200 and 62.4 GeV. In this paper we will study elliptic flow variation with Impact Parameter at above mentioned energies using HIJING event generator models. Elliptic flow is a signal in search of quark gluon plasma.

The lung is an external organ forming the site of unwanted material or particles. In order to protect it, the airways have to be highly effective filters and if the particle deposit they need to be cleared. Inhaled particles can cause a variety of diseases. There are various factors on which the prediction of depositing particles depends, such as age, particle size, flow rate gender, the physics of the particles, the anatomy of the respiratory tract etc.

Present investigation deals with the evaluation of DO, BOD and COD of six surface water resources of Bikaner district which fall in arid region of Rajasthan – a part of Great Indian Desert, to determine pollution status. Water sample analysed for two years 2008-2009 showed these parameters beyond the limit of standard prescribed by WHO. These parameters also showed great seasonal fluctuation, indicating the degree of organic pollution more during summer season and least during winter season.

Liquid crystals are a state of matter intermediate between that of a crystalline solid and an isotropic liquid. They possess many of the mechanical properties of a liquid, e.g. - high fluidity, inability to support shear, formation, and coalescence of droplets. At the same time they are similar to crystals in that they exhibit anisotropy in their optical, electrical, and magnetic properties. We discuss some physical properties of nematic, cholesteric, and smectic liquid crystals (Specially focused on cholesteric) and some applications in laser due to Cholesteric Liquid Crystal’s resonant cavity which formed spontaneously and intrinsically, in the form of self-assembled chiral nematic helix.

Both DC and AC electrical conductivity of materials provide a number of valuable informationon the nature of current carriers, 3-D effects, scattering by defects and impurities, formation of CDW, soliton propagation, non – linear and switching phenomenon and other characters pertaining to these compounds. These measurements are therefore carried out over a wide range of temperature, pressure, electric fields and impurity concentrations. Besides these, the low temperature studies of the materials are performed to determine Optical and Magnetic properties and etc. Therefore, a suitable sample holder is required to perform these studies with low temperature variations. In this paper, we report a design of such a suitable and simple sample holder, which can work up to liquid nitrogen temperature (77 K). This model is easy to fabricate, low cost, more efficient with less wastage in terms of liquid gases than other models. This model can be used for both low temperature dependent electrical conductivity at ambient pressure and clamped high pressure measurements within the given range

World-wide interest on the use of ceramic materials for aerospace and other advanced engineering applications, has led to the need for inspection techniques capable of detecting unusually electrical and thermal anomalies in these compounds. Modern ceramic materials offer many attractive physical, electrical and mechanical properties for a wide and rapidly growing range of industrial applications; moreover specific use may be made of their electrical resistance, chemical resistance, and thermal barrier properties. In this review, we report the development and various techniques for the resistivity measurement of solid kind of samples.

This paper presents the comparison between two solution methodologies Fuzzy Goal Programming (FGP) and ordinary Fuzzy Programming (FP) for multiobjective programming problem. Ordinary fuzzy programming approach is used to develop the solution algorithm for multiobjective functions which works for the minimization of the perpendicular distances between the parallel hyper planes at the optimum points of the objective functions. Suitable membership function is defined as the supremum perpendicular distance and a compromise optimum solution is obtained as a result of minimization of supremum perpendicular distance. Whereas, In the FGP model formulation, firstly the objectives are transformed into fuzzy goals (membership functions) by means of assigning an aspiration level to each of them and suitable membership function is defined for each objectives. Then achievement of the highest membership value of each of fuzzy goals is formulated by minimizing the negative deviational variables.