Papers by Keyword: Glass

Abstract: We make clusters of atoms of the size of less than 1 nanometer by using the density functional theory and from that we obtain the bond lengths corresponding to the minimum energy configuration. We are able to optimize large clusters of atoms and find the vibrational frequencies for each cluster. This calculation provides us with a method to identify the clusters present in an unknown sample of a glass by comparing the experimental Raman frequency with the calculated value. We start with the experimental values of the Raman frequencies of PSe (Phosphorous-Selenium) glass. We calculate the structural parameters of PSe, P4Se, P2Se2, P4Se5, PSe4, P4Se3 clusters of atoms and tabulate the vibrational frequencies. We compare the calculated values with those measured. In this way we find the clusters of atoms present in the glass. Some times, the same number of atoms can be rearranged in a different symmetry. Hence we learn the symmetries of molecules. We find that certain symmetries are broken due to self-organization in the glassy state.

Abstract: Borehole-wall collapse mostly occurs in fractured-rock layers during geological and oil drilling. Steel-casing installation，though with high cost and low efficiency，is currently one of the most fundamental methods for mending broken bore-hole walls. Manufactured casing formed by hot melting，however，provides us an alternative. In order to enhance its qualities，like strength and the capacity of resisting corrosion，of the material，we added bentonite as additive to explore some certain links between properties such as density，porosity, abrasion resistance and different sintering temperatures as well as soaking time.

Abstract: To study the effects of substrate materials on the photocatalytic activity, TiO₂ films were immobilized on the inner wall surface of ceramic, glass and stainless steel tubes by sol-gel method. X-ray diffraction (XRD) results indicated that the crystal form of TiO₂ were all anatase type with theoretical particle size of 15 nm. According to the X-ray photoelectron spectroscopy (XPS) results, appearance of the element Na was observed which would decrease the photocatalytic activity. Scanning electron microscope (SEM) photos showed that the film coating on the ceramic and glass were even and uniform with thickness of about 300 nm and practical particle size of 20 nm to 100 nm. However, the film coating on stainless steel was hackly which would lead to diffraction of lights. The degradation rate constants of methylene blue (MB) with initial concentration of 5 mg.L^-1 were 0.049 min^-1、0.029 min^-1 and 0.023 min^-1 with films coating on ceramic, stainless steel and glass tubes respectively. Degraded with TiO² film coating on ceramic tube, the according rate constants of phenol were 0.37, 0.14, 0.04 and 0.02 min^-1 for initial concentration of 2, 10, 50 and 100 mg.L^-1 respectively.

Abstract: This paper presents an efficient molding technology to fabricate PDMS mask with the help of precision cutting process. At the same time, we have studied the influence of major parameters on the effect of glass erosion rate in powder blasting process. Preliminary results indicate that particledimension and mask opening size can have a decisive influence on the erosion rate. The mask molding technology we have referred can meet the requirement of etching vias through the depth of 500μmglass substrate. Different etching modes can formdifferenthole structures which is suitable for different MEMS devices, enriching elaborate processing technologyfor glass.

Abstract: The great interest toward chalcogenide materials is due to the simple technology of preparation in bulk forms and thin films; good thermal and mechanical properties; transparency and photo-sensibility in the IR spectral range. These advantages determine the possibilities for potential application of these materials like optical storage media, memory devices, optical elements (lenses, waveguides, gratings, etc). The idea of present study is to trace the impact of gallium or indium as metal introduction on the behaviors of the glasses from germanium - chalcogenide system.

Abstract: Interaction parameter A proposed in Yamashita-Kurosawa’s theory of dielectric constant, has been calculated for numerous binary oxide glasses on the basis of polarizability of oxide ion determined from refractive index. However, there are only a few reports on the multi-component oxide glasses system, especially BaO-Bi2O3-B2O3-SiO2 glasses system (G-BBBSO). Bismuth/barium-containing crystals have attracted much attention in application of material engineering because of their importance for the development of nonlinear optical (NLO) information processing technology. Compared to crystals, glasses have shown many advantages in the material engineering, such as easier shaping in casting procedures, low production cost and high thermal and chemical durability. Prompted by these interests in application of material engineering, we reported new data of interaction parameter of BaO-Bi2O3-B2O3-SiO2 glasses system (G-BBBSO) for the different wavelength range (480, 546.1 and 643.8 nm)

Abstract: AST-doped ZnO-MgTiO3-SrTiO₃ ceramics were prepared using a solid-state sintering process. The effects of AST (Al2O3-SiO2-TiO2) on the dielectric properties of MgTiO₃-based ceramics were investigated. The results indicate that AST-doped MgTiO3-based ceramics could be obtained after 1205~1280°C sintering for 3 h. The XRD results indicate that the obtained MgTiO₃-based ceramics contain high percentage of MgTi2O5 phase and the percentage increased with the increase of AST content. It was found that the occurred liquid-phase sintering by adding AST glass could effectively lower the sintering temperature and decrease the dielectric loss of MgTiO₃-based ceramics. A minimum tanδ of 1.5×10-4 associated with εr=19.0 was achieved for 6.0 wt% AST-doped samples sintered at 1255°C.

Abstract: This study aims to investigate the microscopic origin of viscosity by simplifying an amorphous system to a mixture of many independent atomic subsystems. The response of the macroscopic system is then taken as an ensemble average of the relaxations of such subsystems. The result shows that with the reduction of temperature, the overall viscosity changes from the harmonic mean of the subsystems, which is dominated by the fast relaxations, to the arithmetic mean governed by the slowest relaxation. The successful application of our model to the amorphous Selenium indicates the model captures the fundamental mechanism of the viscosity variation.

Abstract: In this modern time with rapidly developing science and technology, packing materials have taken an important role in packing design, and glass packing container takes a huger proportion all the time. Glass’s main raw materials include quartz sand, sodium carbonate, feldspar and limestone and so on. At times, a little bit clarifier, colorant, or opacifier will be blended into the glass. With the procedures of blending, melting, clarifying and homogenizing, the glass will be processed successfully after annealing treatment. Glass packing materials’ workmanship is simple with various forms, and they are apt to clean whilst can be used repeatedly. In modern packing design, glass packing materials have a higher utilization rate, so they have become a kind of indispensable packing materials.

Abstract: Oil Palm Ash is one of the abundance agricultural wastes found in Malaysia. This wastes need to be disposed properly. Oil palm ash contains compounds needed to produce glass. Most of raw materials (especially silica) used to produce existing commercial glass are imported; therefore it is the best time to highlight the potential of local natural waste as the raw material in glass production. In this study, raw material characterization, glass production and glass product evaluation has been done. A few parameters have been recognized to have effect on green glass production such as mixing compositions and firing temperature. Oil palm ash has been washed and dried then sieved to get uniformity of particle size. Then, oil palm ash is mixed with other glass materials such as alumina and flux and undergone melting process at 1400°C. Through the experiments, the best glass compositions are as follows: 80% palm ash, 10% kaolin and 10% feldspar or 10% dolomite while the suitable temperature being used for sintering process to produced end product is range between 1150°C to 1200°.