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In order to study the protection behavior of brittle materials against a shaped charge jet, the jet penetration and the fracture behavior have been investigated by the series of photographs taken by the IMACON high speed camera. The examined materials were glass, fused silica, and single crystalline quartz. The trend of crack growth in BK7 glass and fused silica indicated conical shape. In the case of the single crystalline quartz, it was observed that the crack grows fast along the axis of crystal growth. The velocity of shock wave (~ 6km/sec) into glass and fused silica was faster than the sonic velocity. However, the velocity of shock wave in the single crystalline quartz showed to be similar to its sonic velocity. The ballistic protection capability of single crystalline quartz showing fast crack growth has been evaluated to be lower than that of fused silica which has relatively slow crack growth, although the quartz has higher physical and mechanical properties.

Tilt angle (order parameter) and the susceptibility are calculated as a function of temperature for the $\alpha$–$\beta$ transition in quartz using a Landau phenomenological model. The tilt angle as obtained from the model is fitted to the experimental data from the literature and the temperature dependence of the tilt angle susceptibility is predicted close to the $\alpha$–$\beta$ transition in quartz. Our results show that the mean field model explains the observed behavior of the $\alpha$–$\beta$ phase transition in quartz adequately and it can be applied to some related materials.

The main objective of this research is the explanation of the replacement of feldspar limestone imported from Spain with recycled automotive glass, in order to reduce waste and promote environmental sustainability. Details and efforts of making porcelain ceramics from local raw materials such as quartz, kaolin and glass are also given. Replacing the feldspar with reclaimed automotive glass shows the effect of the Na₂O and CaO solvents contained in the glass on the sintering and crystallization of the studied porcelain. The results showed that the added glass contributes to the reduction of the density and the acceleration of the sintering process, by occupying the sites of the open spaces, observed in the samples not containing feldspars. By reaching a nonporous ratio at a temperature of 1000^∘C, the melting of the material is accelerated due to the dissolved oxides it contains, in addition to the linear shrinkage rate in samples that contain a lot of glass reaching the normal level of porcelain (about 12%) at low temperature compared to ordinary porcelain.

Machining of hard and brittle materials such as engineering ceramics, glass, and silicon is a formidable task. Unlike cutting processes employing plasma and lasers, better machining capabilities of abrasive jet machining are characterized by thermally damaged free surface which is highly competitive as well as important for survival of materials in service. In this paper, an attempt has been made to combine hot abrasives and compressed air to form a hot abrasive air jet. This study aims to analyze the cutting performance in hot-abrasive jet machining (HAJM) of hardstone quartz concerning surface roughness, taper angle (TA), and material removal rate (MRR). Combined approach of Box–Behnken design — analysis of variance, response surface methodology, and statistical technique (here desirability function approach), followed by computational approach (here genetic algorithm), is, respectively, employed for experimental investigation, predictive modeling, and multi-response optimization. Thereafter, the effectiveness of proposed two multi-objective optimization techniques is evaluated by confirmation test and subsequently, the best optimal solution (i.e. at air pressure of 7kgf/cm², abrasive temperature of $64^{\circ }$C, stand-off distance of 4 mm) is used for economic analysis. Result shows that the most significant parameter is abrasive temperature for surface roughness, whereas it is pressure in case of both TA and MRR. Applications of hot abrasives in AJM process have shown attention in enhancing the cutting performance for material removal. Due to lower percentage contribution of error (6.68% to Rz, 9.89% to TA, and 6.42% in case of MRR), a higher correlation coefficient ($R^2$) was obtained with the quadratic regression model, which showed values of 0.92, 0.9, and 0.93 for surface roughness, TA, and MRR, respectively.

The goal of this paper is to improve the technical level of preparing composite photocatalysts with SiO₂-supported nano-TiO₂, expand the selection range of SiO₂ carriers, reduce expenses and understand the influence of SiO₂ crystallization behavior. Natural quartz (Q/SiO₂) powder was used as a carrier to prepare a Q/SiO₂-TiO₂ composite photocatalyst by hydrolyzing a butyl titanate solution and performing high-temperature calcination of the hydrolysate. The performance, morphology, structure and mechanism were tested and characterized. In addition, the as-prepared photocatalyst was compared with other amorphous SiO₂ carrier composite photocatalysts. The results showed that the Q/SiO₂ surface of Q/SiO₂-TiO₂ contained a uniform load of TiO₂ with a 26.98% proportion. Anatase-type TiO₂ was mainly present, and the size was 5–10nm. Moreover, Q/SiO₂ and TiO₂ were firmly combined in the form of Si–O–Ti bonds between the interfaces. The degradation rate of Q/SiO₂-TiO₂ to methyl orange solution was 99.59% under UV irradiation for 60min, which was equivalent to that of pure nano-TiO₂. The degradation performance remained stable after four cycles. Compared with other amorphous SiO₂ carriers, Q/SiO₂ exhibited a higher load of TiO₂. Furthermore, Q/SiO₂ played a more significant role in inhibiting the phase transition of TiO₂ to rutile and improving the photocatalytic performance.

Some people think that carbon and sustainable development are not compatible. This textbook shows that carbon dioxide (CO₂) from the air and bio-carbon from biomass are our best allies in the energy transition, towards greater sustainability. We pose the problem of the decarbonation (or decarbonization) of our economy by looking at ways to reduce our dependence on fossil carbon (coal, petroleum, natural gas, bitumen, carbonaceous shales, lignite, peat). The urgent goal is to curb the exponential increase in the concentration of carbon dioxide in the atmosphere and hydrosphere (Figures 1.1 and 1.2) that is directly related to our consumption of fossil carbon for our energy and materials The goal of the Paris agreement (United Nations COP 21, Dec. 12, 2015) of limiting the temperature increase to 1.5 degrees (compared to the pre-industrial era, before 1800) is becoming increasingly unattainable (Intergovermental Panel on Climate Change (IPCC), report of Aug. 6, 2021). On Aug. 9, 2021 Boris Johnson, prime minister of the United Kingdom, declared that coal needs to be consigned to history to limit global warming. CO₂ has an important social cost…

The chirality (of Greek χείρ, ch[e]ir: hand) is a fundamental symmetry property of three-dimensional objects. Your two hands are not superimposable. They are mirror images of each other. They are therefore chiral (Figure 10.1). The chirality of your right hand can be seen by trying to put it in a glove for your left hand. The same can be seen by trying to put your left hand into a glove for your right hand. The same experience can be done while putting on shoes. Normally you are not comfortable after exchanging the shoe for the left foot with the one for the right foot…

In our previous study, with the dissipation of quartz crystal through material viscosity is being considered in vibrations of piezoelectric plates, we have the opportunity to obtain electrical parameters from vibration solutions of a crystal plate representing an ideal resonator, in which both full and partial electrodes are considered. In fact, the electrodes of resonators are not symmetrically arranged due to the mounting points of crystal blanks are only in one side. As a result, the study of asymmetric electrodes is necessary for practical applications. Different from previous ones, the vibration solutions will contain both symmetric and anti-symmetric thickness-shear vibrations in the electroded area, which will introduce new boundary conditions. We start with the first-order Mindlin plate equations of a piezoelectric plate for the thickness-shear vibration analysis of a resonator with asymmetric electrodes. The electrical parameters are derived with emphasis on the resistance that is related to the imaginary part of complex elastic constants, or the viscosity. With this approach we can further analyze the actual resonator vibration influenced by the electrode position.

Based on the linear piezoelectricity theory, this paper sets up and solves the surface acoustic wave (SAW) wave equation with gyroscopic effect in the piezoelectric medium. Taking three typical piezoelectric materials, quartz, LiNbO₃ and PZT-5H as examples, the influence of substrate rotation on SAW propagation characteristics is analyzed and compared quantitatively. According to the theoretic calculations, not only the different materials but also the same materials with different cut orientations and propagation directions have different SAW gyroscopic effects. Furthermore, the sensitivity of the gyroscopic effect is related to the rotation direction. When the substrate suffers rotation, in most cases the formerly decoupled wave would generate new coupling, but others with certain cuts and rotation axes remain the decoupled state. The rotation induced change of SAW dispersion relation and propagation parameters should be considered and studied when designing SAW gyroscope. The investigations mentioned above provide theoretical guide for the research of SAW devices with gyroscopic effect.

Due to its high Q and temperature stable properties, for many years, quartz crystal based oscillators are important clock sources in consumer, commercial, industrial, and military digital sub-modules and modules. The demand for quartz crystal resonators and oscillators continues to rise. The unique fabrication and encapsulation requirements though render quartz crystal resonators and oscillators difficult or close to impossible to be integrated onto the mature silicon based IC platforms. The recent technical breakthroughs of MEMS (Micro Electro Mechanical Systems) based resonators and oscillators seem to re-ignite the interest in displacing/replacing the quartz crystal technology and to open up again the prospect in clock source integration.

This paper discusses and assesses, from the viewpoint of a quartz crystal manufacturer, such development and its possible impact on the quartz crystal industry which also experiences major progresses in miniaturization, performance enhancement, cost reduction, etc., in the past few years. This paper is not to discredit the MEMS oscillator efforts but to help the quartz crystal manufacturers to understand more about the efforts and advise them what they need to prepare for.

In a detector exposed to high flux of particles (100 Mrad and more) and whose fibres are the active elements one has to know the level of radiation accumulated to calibrate the fibre read-out. This is the case for the forward calorimeter of the CMS experiment at LHC (HF) made of iron as absorber and quartz fibres generating and transmitting Cerenkov light to PMTs. The light spectrum detected is centered near 450 nm (blue). The important transmission variations at these wavelength (few tens %) due to radiation damage and recovery led us to monitor on line the blue light transmission with special fibres called Raddam fibres. Injecting blue light in a 2.5m long fibre, we used the ratio of reflected signal at the two ends to determine the absorption of the fibre. This paper will describe the principle, the construction and tests of this device.

The establishment of an accurate sediment budget, including both inter-tidal sand and mud deposition, requires a reliable chronology for the deposits. This study investigates the application of Optically Stimulated Luminescence (OSL) dating to determine sedimentation rates on a sandy tidal flat, since these sandy deposits are very difficult to date using other techniques (e.g. ¹⁴C and ²¹⁰Pb). An absolute OSL chronology for four sediment cores, recovered from the Danish part of the Wadden Sea is presented. Despite vertical mixing and bioturbation of the tidal sediments, OSL ages ranging from a few years up to ~16,300 years are obtained. The average overall accumulation rates are found to be similar to the local relative sea-level rise, estimated as ~0.7 mm.a^-1 in this area. The tidal flat is concluded to have had a positive sediment budget during the last 100 years and the new approach, using OSL dating, shows promising results.

The TOP counter is a ring imaging Cherenkov detector, which is used for particle identification in Belle II. It mainly consists of two quartz radiator bars and micro-channel-plate photomultiplier tubes (MCP-PMTs). Production benches for the TOP counter were established; the quantum efficiency and the transit time spread of the MCP-PMTs can be measured with a precision of 2% and 4%, respectively; and the two quartz bars can be glued with and precisions of the relative position and angle, respectively.

In order to improve the sinterability of MgO-CaO system materials. Use light burned dolomite, light burned magnesite as main raw materials, quartz and zirconium silicate as additives to made 2 groups of samples respectively: 1) Quartz is added to mixture including light burned magnesite and dolomite that wt.(MgO) is 65% to make wt.(SiO₂) is 5%, 10%, 15%, 20% respectively; 2) zirconium silicate is added to mixture including light burned magnesite and dolomite that wt.(MgO) is 65% to make wt.(ZrSiO₄) is 5%, 10%, 15%, 20%, 25% respectively. The samples formed sintered respectively in 1550°C, 1600°C, 1650°C, 1700°C for 2 hours to test samples' bulk density, open porosity and microstructure to investigate the effects of additives on the sintering property of magnesia calcium materials. The results showed that: SiO₂ had better not more than 5%; the samples are best when zirconium silicate is 15%.