International Journal of Modern Physics B

This paper discusses the influence of Vietnam rare earth (RE) with the composition of 69.4% Ce and 30.5% La (modification content of 4% and 6%) on the microstructure and mechanical properties of Al–5Zn–3.5Mg–1.2Cu alloy when the temperature modification is changed at $750^{\circ }\mathrm{\text{C}}$ in 150, 200, 250 s. By optical microscopy, the results showed that the microstructure of the modified sample is finer than the nonmodified sample. By the SEM and EDS analysis, at the grain boundaries of this alloy, ${\mathrm{\text{MgZn}}}_2$ and/or ${\mathrm{\text{Mg}}}_3{\mathrm{\text{Zn}}}_3{\mathrm{\text{Al}}}_2$ intermetallic phases appeared. The modified elements (La, Ce) in RE and aluminum were formed in the intermetallic ${\mathrm{\text{Al}}}_{11}{\mathrm{\text{RE}}}_3$ and ${\mathrm{\text{Al}}}_2\mathrm{\text{RE}}$ phases, which prevents the development of the dendritic $\alpha$ phase. The result showed Al–5Zn–3.5Mg–1.2Cu alloy modified with 4% RE in 150 s which is the most optimal result, the grain size is $6.67\mu \mathrm{\text{m}}$ and the hardness is 107 HB.

This paper presents results of study in building diagnostic regressive models (RMs) of cylinders in Marine Diesel Engine (MDE) using torsional vibration signal (TVS) on the propulsion shaft-line. For diagnostic purpose, the vectors of diagnostic signs (VDS) were designed and constructed based on the features of the TVS: maxima and minima relatively with $z$ working cylinders in real-time domain, or amplitudes of $M_h$ first harmonics ($M_h=12$ for two-stroke MDE, and $M_h=25$ for four-stroke MDE) in frequency domain. The received RMs are equations showing the relationships between the diagnostic sign $Vk$, $k=1,\dots ,n$ ($n=z$ or $n=M_h$) of the TVS and $z$ factors $x_i$, $i=1,\dots ,z$ which specify common states of $z$ DME’s cylinders. The factor $x_i$ here was calculated by using firing coefficient Cfi ($x_i$ = 2Cfi-1; Cfi = 0 when $i$-cylinder is misfired, and Cfi = 1 when $i$-cylinder is normally fired) value of each cylinder. The Fractional Factorial Design of experiments (DoE) $2^{z-m}$ was used to build the mentioned RMs. The MDE on MV.HR.34000 DWT, with $z=6$ and $m=3$ was observed and analyzed. The calculated linear regressive models were tested based on the $F$-distribution standard.

Core–shell structure ${\mathrm{\text{Fe@TiO}}}_2$ was synthesized by sol–gel method. The photocatalytic degradation of methylene blue over the ${\mathrm{\text{Fe@TiO}}}_2$ reached 98% under UV light irradiation within 5 h. The band gap of the core–shell ${\mathrm{\text{Fe@TiO}}}_2$ was found to have a redshift through a sintering treatment. The redshifted ${\mathrm{\text{Fe@TiO}}}_2$ had a good performance of methylene-blue degradation (reaching 85%) under visible light irradiation for 5 h.

Screw air compressors have been being used widely for 45 years. There are many research works on these machines, but there have been still many problems, especially on designing and machining their screw pair, to study. This paper focuses on gate screw profiling from the main screw profile and disc tool profiling for manufacturing the screw pair. The air compressor screw 3D model pair, designed by using the proposed methods, have satisfied the meshing condition. The disc tool 3D models created for machining the screws have also been tested in many ways, these testing results show high accuracy of the disk tool 3D model, which can be used in industrial manufacturing.

In this paper, the Photoplethysmography (PPG) signal response of humans under different perceptual stimuli was mainly discussed. The autonomic nervous system (ANS) regulates the functioning of organs or tissues in the body to make the body adapt to the environment. When the human body is stimulated, it can obtain information about ANS from the analysis results of heart rate variability (HRV).The proposed method is used with PPG signals for time domain and frequency domain analysis to obtain HRV parameters and short-time Fourier transform (STFT) output heat map, respectively. Different environmental stimuli were given during the experiment and changes in PPG signals were observed. There were eight males and eight females with a total of 16 subjects with an average age of 24 years. Heart rate was observed to vary with stimulation in 16 subjects. The heat map clearly distinguishes whether the subject is affected by the stimulus and causes the ANS to regulate the human body. The data obtained under various stimuli are directly compared and measured from physiological signals. It can establish an objective patient’s current emotional judgment and can be used to explore the patient’s diagnosis status during the diagnosis process.

Slag fiber has economic and environmental advantages in that it converts a low-value-added material to a high-value-added material. However, although the slag fiber has a chemical composition similar to basalt fiber, its competitiveness in the fiber industry is significantly lower. Moreover, the slag fiber remains in the pre-commercial stage due to the uncertainty and instability of the basic properties. Therefore, in this study, the slag fiber customized through the fiberization process was compared with the existing basalt fiber to analyze the effect of the similarity of chemical composition on the environmental degradation characteristics and mechanical properties under tensile loading. As a result, the slag filament composites showed lower tensile strength due to the weaker interfacial bonding strength with the epoxy matrix than the basalt filament composites, but the difference in decreased tensile strength rate was not significant. In addition, long-term moisture absorption in fresh water and seawater demonstrated excellent moisture absorption resistance.

This paper proposes a method for high-precision radius measurements. The proposed system uses a frequency-modulation technique to improve the accuracy of detecting cat’s eye and the confocal position of a lens. The distance between two points defined as the radius of a lens was measured by using a frequency-modulated Michelson interferometer. In the confocal part, when the tested lens was moved along the optical axis, the intensity at the detector reaches a maximum at the confocal and cat’s eye positions of the sphere. Synchronous detection technique is used to turn the intensity signal from the detector into an odd-symmetry signal through a zero point. These symmetry points coincide with cat’s eye and confocal positions and thus enhance the accuracy with which these two points are detected. A frequency-modulated Michelson interferometer is used to accurately measure the displacement when moving the test sphere between the confocal and cat’s eye points.

This paper presents some results of simulation using ANSYS CFX software in design air spindle which has the structure in the form of orifice and grooves to ensure uniform pressure distribution and avoiding air hammer; it is also easy to manufacture and reduces costs. The results of simulation are good in investigating operation of air-spindle which is changed some parameters to find the optimal working mode for the air spindle with speed in the range of 5000–20,000 rpm.

Thermal-assisted machining (TAM) is an effective processing solution to improve productivity and product quality made from materials with high strength and hardness. This method is widely used in nonchip machining such as forging, stamping, deep drawing, etc. For the method of heating on the molds, it is possible to control local heat or uniform heat on the workpiece. However, the calculation of heat capacity, heat transfer as well as the heating time to achieve the temperature on the workpiece is necessary to design suitable molds and heating system. This study focuses on a heating system that uses single-sided thermostatic heating rods to heat the molds, verify the effect of the heating time on the temperature of the workpieces and then control the temperature on the workpieces at various heat levels through a heating control system. Thereby, this study proposes to build a mathematical model between temperature and heating time on the workpiece.

In this paper, three-dimensional images were used to analyze the association between dose-volume parameters and radiation-induced brain edema in patients with a brain tumor after receiving stereotactic radiosurgery (SRS). The computed tomography (CT), magnetic resonance images (MRI) and treatment parameters were transferred through the treatment planning system (Multiplan, version 5.1.3). The correlation between the dose of radiation therapy and brain edema was evaluated by image processing methods, such as image normalization, registration, filtering, segmentation, and feature extraction. The association was evaluated by volume index and intersection index. The study results suggest that the volume receiving radiation dose above 30% of the prescribed dose is highly associated with the brain edema in brain tumor patients after SRS. The small number of patients limits the study. Further investigation with larger populations and long-term epidemiological studies are required.

The grinding process of Titanium (Ti) alloys is extremely difficult as the cutting temperature is much higher than other machining processes due to the low thermal conductivity, high chemical reactivity, and rapid work hardening during machining of Ti alloys. This research investigates the effect of technology parameters on the surface roughness in the surface grinding of Ti–6Al–4V (Ti64) alloy with resinoid cBN grinding wheel. The experimental results show that the surface roughness is significantly affected by the feed rate, depth of cut (DOC) and cooling condition. Increasing feed rate or DOC all provides the higher surface roughness. The surface roughness obtained in the wet grinding is higher than those of the dry cutting. The scanning electron microscopy (SEM) images of Ti64 surfaces show that the machining surface with fewer defects can be produced with wet grinding process.

Monitoring vibrations (VMs) of the sea-going ships are necessary to measure and control under the Rules for Classification and Construction of Sea-going Ships of some national registers, such as Russian Maritime Register (RMR) of shipping, Edit 2014. The VM is important and necessary for safety marine diesel engine (MDE) in its technical operation at dangerous levels of torsional, axial or lateral vibrations (TVs, AVs, LVs), which appear in practice at some abnormal regimes, especially on the two-stroke MDE and its main propulsion plant (MPP). This paper presents the results of experimental study for monitoring vibration of the four-stroke MDE, and it’s MPP in the sea — trail test of the MV.KN168, designed and manufactured by Hong Ha Shipyard (Haiphong, Vietnam, 2017). The vibration signals were measured and analyzed using Multi-channel Measurement and Monitoring Vibration System (MMMVS) made by Vietnam Maritime University (VMU).The vibration research results on the four-stroke MDE of the MV.KN168 indicated that the vibration levels of the every measured position lie in the allowable limitations.

In this paper, selective laser sintering (SLS) was applied to join two materials by printing Ti–6Al–4V powder on a Ti substrate without any support parts. The characteristics of the interface between the as-built Ti–6Al–4V sample and the substrate were investigated. The analysis indicates that a heat-affected zone (HAZ) and the fish-scale type were formed at the joining area. The combination of smaller grains, acicular ${\alpha }^{\prime }$ martensite, and lamellar $(\alpha +\beta )$ structures was observed inside the interface zone. The hardness value at the interface area was measured by about 320 HV which is higher than 280 HV of the substrate and smaller than 369 HV of the as-built sample. The results predict that the SLS process is a promising method for manufacturing of hybrid materials.

Mantispids are small brown bugs about 1.5 cm in length. Mantispid eggs are produced in large quantities, with about 1000 eggs per spawning, and are tiny and densely packed. Traditionally, mantispid eggs are counted manually. However, counting such a large quantity of eggs is difficult. To provide accurate data for researchers, we detail methods to accurately detect and count the number of mantispid eggs using image processing. The following methods were used to count the mantispid eggs: background estimation, morphological image processing, background subtraction, stretching, image thresholding, gray-level transformation, labeling and counting. The results of automated counting were compared with the results of manual counting. The segmentation results were verified, and the accuracy of the mantispid egg counts was determined to be 100%. This provides a useful resource for mantispid egg counting. The automatic counting system cannot only count mantispid eggs, it can also be used to count other similar insect eggs.

The movement of a piston rod in a pneumatic cylinder is directly affected by the air humidity in the atmosphere, especially in the case of piston rods without any means of protection or grease on their surfaces. In a pneumatic cylinder system, the friction between the piston rod and the rod seal is sliding friction, and it has a significant value that varies with the variation in the moisture on the piston rod’s surface. In this paper, an investigation of the friction characteristics of piston rods and rod seals in a pneumatic cylinder was carried out with different humidity and velocity values to understand the effect of lubricants on the moving parts of pneumatic systems in humid environments, where the friction characteristics of the displacements corresponding to the static and dynamic friction forces were displayed on a measuring device. The research results showed that the static friction forces tended to decrease by $10\%÷16\%$ and that the dynamic friction forces tended to decrease by $14\%÷24\%$ when the relative humidity increased from 51% to 99% at different velocities between 5 and 100 mm/s.

This paper’s aim is to describe the results of the phase transformation of BCuAl₉Fe₄ alloy after casting, quenching and aging. After casting, the microstructure of this alloy consists of $\alpha$ phase with grain size about 100 $\mu$m, mixture $(\alpha +\gamma )$ and the inter-metallic phase Fe₃Al. However, the proportion of the $\alpha$ phase in the casting alloy is coarse. The alloy was heated at $850^{\circ }$C for 2 h then quickly cooling in water. After quenching, the microstructure of alloy shows that the grain size reduced to about 40 $\mu$m. After quenching, the alloy was aged at $350^{\circ }$C for 2 h, the martensite phase of this alloy decomposed into order phase ($\alpha +{\gamma }_2)$ with fine grain size, dispersed in the matrix. The intermetallic phase was fine and evenly dispersed in the matrix. By TEM analysis, after heat treatment, the structure of martensite and the inter-metallic phase in this alloy which had small grain size were formed.

The vacuum pump usually used traditional curves such as the circular, cycloidal curves and their combinations to construct tooth profile. However, to increase efficiency and design flexibility for the vacuum pump, a novel rotor tooth profile for Roots rotor of vacuum pumps is proposed. Which is named “CEIEC” tooth profile and orderly composed of five significant segments, a circular arc for tooth tip, an epicycloid curve with variable extension, an involute, an enveloped epicycloid curve and a conjugated circular arc for tooth root. A numerical example is presented to evaluate the performance indices for proposed vacuum pump, including the hermeticity coefficients of the rotor mesh gap and tip gap.

Aircraft approaching is the most dangerous phase in every complete flight. To solve the pressure of air traffic controllers and the landings delayed problems caused by the huge air traffic flow in Terminal Control Area (TCA), an automatic Air Traffic Control (ATC) instructions system is initially designed in this paper. It applies the fuzzy theory to make instant and appropriate decisions which can be transmitted via Controller-Pilot Datalink Communications (CPDLC). By means of the designed system, the decision-making time can be saved and the human factors can be reduced to avoid the flight accidents and further delays in aircraft approaching.

Predicting the quality of the machined components is the grandiose signification in industrial manufacturing. Calculation of the surface roughness is one of the most important elements to predict the quality of machined parts. In this paper, the surface roughness was modeled in the face-end mill process by using general rhombu insert. In the proposed mathematical model, with the stable milling condition, the surface roughness is formulated by a function of feed rate, and insert geometry such as nose radius and nose angle. An experimental method is proposed based on the stable milling condition to estimate the surface roughness. The developed surface roughness calculation model has been successfully verified by both simulation and experiment with very promising results. The average difference between predicted and experimental results is 7.59%. The proposed model can be applied to predict the surface roughness in face-end mill processes by using general insert at stable cutting condition.

In manufacturing, thickness distribution and maximum thinning greatly affect product quality in sheet metal forming. They depend on many input parameters, such as technological parameters, geometric shape of die, workpiece’s materials and forming methods. Hydrostatic forming technology is particularly suitable for forming thin-shell products with complex shapes. However, due to the forming characteristics, the thinning phenomenon in this technology is much more intense than in other forming methods. Therefore, this study aims to determine the thickness distribution and the relationship between the maximum thinning ratio and input parameters including blank holder pressure, relative depth of the die and relative thickness of the workpiece in this technology. The chosen product shape is cylinder and the chosen method is the orthogonal second-order design. The results are expressed in graphs and functions and they can be applied in product design, calculation and control of input parameters in industrial manufacturing.

This study deals about the influence of vibrations incorporated into a workpiece during powder-mixed electrical discharge machining (PMEDM) on quality measures such as material removal rate (MRR), surface roughness $(R_a)$ and microhardness. It has been found that the low-frequency vibration incorporated into the workpiece positively affects the processing efficiency of electrical discharge machining (EDM) and PMEDM. However, the effect of low-frequency vibration in PMEDM has been better than EDM. The higher vibration frequency significantly improves the MRR and $R_a$ in PMEDM. The MRR has been improved by 95.89% and with lower $R_a$ of 63.2% in PMEDM. The hardness of the machined surface after PMEDM using titanium powder mixed in dielectric liquid was increased approximately two times as compared with conventional EDM.

Encoder is the measurement device that plays an important role in the electronic industry. In the process of manufacturing, the current mechanical testing methods are not of very high accuracy or are having problems in data processing algorithms. In this paper, the author represents a method for the testing mechanical work of an encoder product by measuring the torque induced by rotating the encoder. The advantages of this method are the high accuracy, stability and low cost. The accuracy of this method can go upto 95–98%. The measurement system uses LabView software as the data processing application and NI instruments as the data acquisition tools.

3D printing technology has emerged as a high value-added industry with high efficiency that has dramatically broken away from the existing material and manufacturing industry’s human-based production system. These technologies, ranging from small parts to large structures, are rapidly developing due to the challenge of various filament materials, whereas there are significant concerns about waste filler materials, and complimentary research is needed to improve them. Polylactic acid (PLA), the representative polymer of 3D printing, contributes to minimizing environmental risks. However, although thermoplastic PLA has excellent reversible properties for heat in terms of sustainable resources, it is degraded as a low value-added material afterward. Therefore, in this study, the effect of repetitive recycling on the mechanical and thermal properties of PLA filaments was analyzed to verify and re-evaluate PLA as a renewable resource. As a result, recycled PLA has decreased tensile and flexural strength by up to 69% and 53%, respectively, compared to initial neat PLA with the increase of the number of repetitive recycling, and this demonstrates the change in the thermal properties of recycled PLA.

In this study, we investigate the effect of fluorine (F${}_2)$ flow rate on the crystal characteristics and chemical bonds of Al-Doped ZnO (AFZO) Films. At first, 1 wt% Al₂O₃ was mixed with 99 wt% ZnO to form the Al-doped ZnO ceramic target, the radio frequency (RF) magnetron sputtering method was used to deposit the AFZO films by introducing different flow rates of F₂ gas using F₂/(Ar + F₂) mixing atmosphere during the deposition process. F₂ flow rates (F₂/(Ar + F₂)) were changed in the range of $0\sim 0.25$%, and F₂ ratio was controlled using the mixing gases of (F₂(5%) + 95% Ar) and pure Ar. AFZO films were deposited on the EagleXG glass and the films’ thickness was about 330 nm by controlling the deposition time. After AFZO films were deposited, their crystalline structure and electrical characteristics were well investigated. Finally, a comparative study of surfaces of AFZO films was investigated using X-ray photoelectron spectroscopy (XPS) to find the variations of the chemical bonds as the deposition temperature and F₂ flow rate were changed.

The classical molecular dynamics (MD) technique was used to investigate the atomistic structure of amorphous hafnium oxide (HfO₂) under pressure. The local atomic structure and the liquid-solid transition of HfO₂ were analyzed for the pair radical distribution functions, bond angle distributions and coordination number. The simulation reveals that although the fractions of structural units HfO${}_x$ and OHf${}_y$ strongly change with the density, the partial bond angle distributions of these structural units are almost identical for all constructed models. This result has enabled us to establish a relationship between the bond angle distributions and the fractions of structural units.

The vibration during external cylindrical grinding is caused by many factors such as the rigidity of the technology system, machining modes, machining materials, cooling mode, etc. This paper employed a Taguchi method to design experiments and evaluate the influence of machining mode parameters and workpiece material hardness on the vibrations when machining some types of alloy steel in external cylindrical grinding process. The influence of machining conditions on the vibrations was investigated. Besides, the mathematical models of vibration amplitudes were also modeled. The achieved results can be used to control the vibrations through machining conditions to improve the surface quality of the product.

This paper presents a method for estimating vehicle speed using two roadside passive infrared (PIR) sensors whose optical axes are parallel to each other and perpendicular to the moving direction of vehicles. The vehicle speed was calculated based on the time lag between the two signals received by the PIR sensors, which was evaluated by using cross-correlation analysis. The experiments show that the method has an error of less than 5 km/h over a speed range of 20–60 km/h.

This paper explores the mechanism design of a balloon machine representing a vending machine where consumers can select their desired shapes, as well as avoid bursting caused by manual inflation. Inside the machine, balloons are placed on the mechanism designed based on a waterwheel which rotates at a constant speed generated by motion among different sizes of gears. When rotating to the corresponding shaped balloon, the inflator will move under the opening to pull it out from the display point and start to inflate the balloon for the set number of seconds. After the inflation is completed, the glass door will open and the customer can take out their balloon. The main purpose of our development and design of the balloon machine is to improve the general balloon blowing and it is easy to prevent over-exposure and blast. The balloon machine can automatically inflate and detect the blowing time to improve the shortcomings of the balloon’s blast. In this way, it can effectively decrease sudden explosions and the number of frightened people.

In this study, the effects of low-frequency vibrations on machining SKD61 steel workpiece in electrical discharge machining (EDM) with titanium powder-mixed dielectric fluid were investigated. The results showed that the vibrations incorporated into the workpiece in powder-mixed EDM (PMEDM) led to significant improvement in machining efficiency. The material removal rate had the maximum increase of 141.7% with 70.2% of lower electrode wear rate and 69.9% of lower surface roughness. Hence, it is proved that the effectiveness of vibration in PMEDM can be improved.

Wire arc additive manufacturing (WAAM) has received much attention for manufacturing metal parts with medium and large dimensions because of its high deposition rate and low production costs. In this study, the effects of the heat input on the microstructure formation of thin-wall low-carbon steel parts built by a WAAM process were addressed. The mechanical properties of built materials were also studied. The results indicate that the heat input significantly influences on the shape of built thin walls, but has slight effects on the microstructure evolution of built materials. The WAAM thin-wall low-carbon steel presents suitable microstructures and good tensile strengths (YS: 320 – 362 MPa, UTS: 429 – 479 MPa) that are adequate with industrial applications.

Behavior models are proposed for HSPICE simulation of first-, second- and third-generation current conveyors. They can be used to speed up the exploration and verification of current conveyor-based circuit designs. To demonstrate the feasibility and workability of the proposed HSPICE simulation models, they are used as the current measuring devices for grounded and floating current sensing, and the simulation results are consistent with the theoretical expectation. The flexibility in the current sensing capability of the CCIII is also shown by a practical example using the behavior model. HSPICE simulation results are given.

In surface finishing of a grinding machine, the dimension accuracy of the workpiece is most affected by the stiffness of the spindle. For the hydrostatic spindle of a medium-sized circular grinding machine, the primary factors affecting the oil film stiffness are bearing structure parameters, lubrication characteristics, and working conditions. In this study, the effects of lubricant pressure and oil viscosity on the stiffness of the hydrostatic spindle based on the working conditions were investigated. The oil viscosity affects the spindle by increasing the stiffness that corresponds to the increase in viscosity in the range of 0.001–0.002 Pa$\cdot$S, while the stiffness proportionally increases with pump pressure changing in the range of 3–5 MPa. Experimental results also indicate that based on the stiffness of the bearing, a viscosity of 0.002 Pa$\cdot$S, pump pressure of 5 MPa, and load range of 500–1000 N are the most feasible working conditions for hydrostatic spindle associated with the fine-machining process on a medium-sized external grinding machine.

Three-dimensional (3D) CAD models are useful for applications in the areas of CAD/CAM/CAE/CAQ. A desirous trend creating this model is a 3D model reconstruction from views. With this method, geometric information can be easily entered into computers while continuing to use existing 2D drawings in modern applications. Most of the previous works used three views as the input despite many common parts represented by only two views. A reconstruction system using only two views is the subject of this work. The proposed method has been implemented and tested by an Objectarx 2015 program running on AutoCAD 2018. The resultant 3D Solid model has been evaluated for compatibility with CAM/CAQ/CNC systems.

Forming fluid pressure is an important technological parameter that determines whether a product can be accurately formed according to the size and profile of the die in hydrostatic forming technology. The expected value of this parameter is often very high because it acts as the punch in forming complex products from sheet metal. However, it is difficult to achieve high values because the forming fluid pressure depends on the ability to hold high pressure of equipment system and input parameters including the blank holder pressure, the depth of die, the thickness of workpiece. Moreover, it is also necessary to have a mathematical model for this parameter to facilitate the calculation and control of the forming process. In order to solve the above problems, this paper will indicate a simple way to avoid the pressure drop during forming process, and establish a regression function relationship between the forming fluid pressure for typical cylindrical product and input parameters above by experimental research method. The results contribute to die design, calculation and control of process parameters to facilitate shaping thin shell products in actual hydrostatic forming technology.

We had successfully synthesized green-emitting phosphors based on Li₂BaSiO₄ material activated by bivalent europium ions (Eu${}^{2+}$) using a solid-state reaction method in a reducing gas environment and investigated their luminescence properties. The Li₂BaSiO₄:0.003Eu${}^{2+}$ (LSB-Eu) phosphors were synthesized at 850${}^{\circ }$C for 1 h, and the reduction gas was removed at 500${}^{\circ }$C, 600${}^{\circ }$C, 700${}^{\circ }$C and 800${}^{\circ }$C, respectively. XRD pattern showed that the Li₂BaSiO₄, Ba₂SiO₄ and Li₄SiO₄ phases were observed in the synthesized Li₂BaSiO₄ composition. As the reduction gas was removed at 800${}^{\circ }$C, the LSB-Eu phosphor emitted a weak red light rather than a green light. Two weak emission peaks were found at about 588 nm and 613 nm corresponding to ${}^5{\mathrm{\text{D}}}_0\to {}^7{\mathrm{\text{F}}}_1$ and ${}^5{\mathrm{\text{D}}}_0\to {}^7{\mathrm{\text{F}}}_2$ transitions. As temperature to remove the reduction gas was lower than 800${}^{\circ }$C, the emission spectra of LSB-Eu phosphors reveled a broad peak centered at 501 nm, which emitted a green color. The intensity of photoluminescence excitation (PLE) photoluminescence emission (PL) spectra increased as the removing temperature was decreased from 700${}^{\circ }$C to 500${}^{\circ }$C and saturated at 500${}^{\circ }$C. These results show that LSB-Eu can be a noteworthy candidate of green-emitting phosphor for the investigation of white light-emitting diodes (WLEDs).

Foil-air bearings have presented their advantageous performance due to their different structures when compared to traditional air bearings. However, it is the nonlinear characteristic of this kind of bearing that has drawn studies on dynamic response of the rotor-bearing system, especially rotor stability. In this paper, an improved foil dynamic model with internal bending moment included has been proposed to determine the nominal stiffness of the foil structure. Based on that, the nominal stiffness of the foil structure has been investigated with different geometry parameters of the foil structure. By such means, the stability of the rotor-bearings system has been theoretically studied through an equation system in a common turbocharger structure. The results can be effectively used for designing and suitably selecting some geometry parameters of foil-air bearings to have a good rotor performance in this case.

In this study, by performing the experimental research, the surface roughness, cutting force and vibration were modeled. The Genetic Algorithms (GAs) were applied to determine the optimal values of external cylindrical grinding conditions to achieve the minimum value of surface roughness and the maximum value of the material removal rate. The optimum values of surface roughness and material removal rate are 0.490 $\mu$m and 3.974 mm²/s, respectively, that were obtained at a feed rate of 0.3 m/min, at a workpiece speed of 164.82 rpm, at a cutting depth of 0.015 mm, and a workpiece Rockwell hardness of 56.32 HRC. The optimal values were successfully verified by experimental results with very promising results.

This study presents a technique requiring relatively simple supporting devices and protection accessories for treating conditions like mycosis fungoides in which a uniform radiation dose to the whole body can be achieved by using the regular largest electron cone instead of HDRe${}^{-}$ mode in one treatment course. The regular cone total skin electron therapy technique presented in this study is able to deliver a uniform radiation dose to the patient’s skin surface. The result is satisfying when compared with the High Dose Rate e${}^{-}$ (HDRe${}^{-}$) Stanford Six Field Technique.

The vertical tyre force is crucial to the study of the dynamics of a tractor semi-trailer. The paper presents an experimental method for determining the vertical tyre force by determining the vertical acceleration of the un-sprung mass and the vertical acceleration of the sprung mass when the tractor semi-trailer moves. The results of this study form the basis for determining the dynamic tyre force without the installing of sensors on road.

Electrical discharge machining (EDM) process is widely used to process hard materials in the industry. The process of electrical discharge is changed and called PMEDM when alloy powder is added in the oil dielectric. In this study, the effect of tungsten carbide alloy powder added in the dielectric on the microhardness of surface (HV) status of the workpiece SKD61 after machining is investigated. Studies show that the microhardness of surface obtained by PMEDM is generally better than that by normal EDM. The experiment shows that at the selected process window, adding the powder has resulted in an improvement of the microhardness up to 129.17%.