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Results in Journal New Journal of Glass and Ceramics: 111

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Zahid Hussain
New Journal of Glass and Ceramics, Volume 11, pp 1-33; doi:10.4236/njgc.2021.111001

The values of refractive index (n) for silicate glasses (silica, soda lime and borosilicate 7059) are decreased from 1.5119 to 1.5111, 1.5086 to 1.5065 and 1.5296 to 1.5281, respectively; and the optical band gap (Eg) is increased from 9.8 to 9.81 eV, 9.845 to 9.88 eV and 9.56 to 9.58 eV, respectively over the temperature range 295 - 473 K using ellipsometer at wavelength 632.8 nm. While n is decreased from 1.5276 to 1.5274, 1.5074 to 1.5070 and from 1.5283 to 1.5281, respectively; and Eg is increased from 9.59 to 9.592 eV, 9.862 to 9.870 eV, and 9.574 to 9.58 eV, respectively over the temperature range 297 - 322 K using Abbe refractometer at wavelength 589.3 nm. The values of oxide ion polarizability [αo2- (n) and αo2-(Eg)] regarding silica, soda lime and borosilicate 7059 glasses are decreased from 1.3427 to 1.3408, 1.6014 to 1.5941, 1.4329 to 1.4193, respectively over the temperature range 295 - 473 K using ellipsometer; and are decreased from 1.3786 to 1.3764, 1.5991 to 1.5969, 1.4297 to 1.4191, respectively over the temperature range 297 - 322 K using Abbe refractometer. Similarly, the values of optical basicity [A (n) and A (Eg)] of silica, soda lime, and borosilicate 7059 glasses are decreased from 0.4272 to 0.4245, 0.6271 to 0.6224, 0.5045 to 0.4933, respectively over the temperature range 295 - 473 K using ellipsometer; and are decreased from 0.4586 to 0.4567, 0.6256 to 0.6242, 0.5018 to 0.4930, respectively over the temperature range 297 - 322 K using Abbe refractometer. Further, we have found that for silica, soda lime and borosilicate 7059, the values of electronegativity (ξ1av) QUOTE ζ1av) using Zahidnumerical model [based on αO2- (n) and A (n)] are increased from 5.1035 to 5.5504, 4.0393 to 4.830, 4.8143 to 5.0111, respectively over the temperature range 295 - 473 K using ellipsometer; while these values are increased from 5.0657 to 5.2149, 5.0657 to 5.2149, 4.8357 to 5.0111, respectively over the temperature range 297 - 322 K using Abbe refractometer. It is very clear from this research report that both refractive index and optical band gap-based-oxide ion polarizability and optical basicity have the same decreasing trend as the temperature is increased, and this trend indicates that the reported glasses have a very small amount of electronic polarizability. Moreover, this decreasing trend occurs due to the decreasing amount of non-bridging oxygen (NBO) which in turn caused a decrease in refractive index within the silicate glass system at higher temperature. Since the calculated values of electronegativity are found to be in the range 4.0393 - 5.5504 for the reported silicate glasses, so all these glasses have an ionic character. Moreover, low values of optical basicity and of oxide ion polarizability suggest that the silicate glasses are not novel glasses (optical functional glasses) for non-linear optical (NLO) devices or for three dimensional displays.
Nada Elbaz, Gomaa El-Damrawi, Amr M. Abdelghany
New Journal of Glass and Ceramics, Volume 11, pp 34-43; doi:10.4236/njgc.2021.111002

A new type of cerium borate glass-ceramic is prepared and studied. The microstructure and crystallization behaviors of the glass samples were investigated by X-ray diffraction (XRD), electron diffraction (ED), and 31P NMR spectroscopy. The microstructures of samples contain 2 are amorphous in nature. More addition of CeO2 transforms the glass to glass-ceramics without thermal annealing. The morphological change of the microstructure of these materials was followed by transmission electron microscopy (TEM). The obtained results have revealed that the addition of more than 0.8 mol% CeO2 can promote nucleation and crystallization routes that are combined with the establishment of diverse crystalline phases. Glasses with lower contents of CeO2showed no tendency to crystallization. The crystals of CeO2 containing glasses were spheroid like morphology that was assigned to the three-dimensional fast growth of the well-formed structural species in the boro-apatite phase. In addition, the cerium free glass is characterized by particle-like morphology. Then the growth of spheroid species in three-dimension plays better compatibility and bioactivity behavior than that of the other types of morphology. This is may because the spherical shape has a higher surface area than that of the needle-like morphology. Accumulation and aggregation of small-sized spheres from cerium borate phases played the role of enhancing the hardness of the studied materials.
O. Ighere Jude, Alex Greaney P., Jude O. Ighere, P. Alex Greaney
New Journal of Glass and Ceramics, Volume 10, pp 15-27; doi:10.4236/njgc.2020.102002

Thermal storage potential and thermal expansion are characteristic properties for extreme applications. ZrB2 is a candidate for advanced applications in aircraft and fusion reactors. This article presents density functional theory calculations of its states, microstructure and quasi-harmonic levels calculations of thermophysical properties. Band structure highlighted dynamical instability with metallic impurities in ZrB2 structure based on frequency modes. The observed projected density of states (PDOS) appropriate 4d orbital of Zr dominated at low frequency both in perfect crystal in the presence or absence of covalent impurities while B 2s and 2p orbitals dominate higher frequency states. Temperature dependency and anisotropy of coefficient of thermal expansion (CTE) were evaluated with various impurities. Various thermodynamic properties like entropy and free energy were explored for degrees of freedom resulting from internal energy changes in the material. Computed results for heat capacity and CTE were compared to available numerical and experimental data.
Vahdat Astani Chee, Junfeng Yang, Zuyuan Yu, Astani Che Vahdat, Yang Junfeng
New Journal of Glass and Ceramics, Volume 10, pp 1-13; doi:10.4236/njgc.2020.101001

The quality of a via hole on a multilayer stack of Low Temperature Co-fired Ceramic (LTCC) tape is of utmost importance to its functionality. This paper investigates a substitute for the commonly used circular shape hole to a more complex one and its implications when different parameters such as sheet thickness, punch speed, travel distance and tool clearance are changed. Fabrication of the punch tools and the punching process is carried out at the same machine, ensuring alignment. Two types of non-circular shape are chosen to carry out the experiment. Pre-sintered complex shape hole measurements show that while punch conditions such as speed and tool gap have little effect on the size, sheet thickness and travel depth play a vital role in the overall dimension. Albeit having only a slight effect on the size, those parameters are significant in other aspects of hole quality. Post-sintering investigation is also observed and discussed.<
Norhan Atef, Gomaa El Damrawi, Abdelmagud Hassan, Lobna Sharaf El-Deen
New Journal of Glass and Ceramics, Volume 10, pp 45-56; doi:10.4236/njgc.2020.104004

This work is aimed to shed light on the dielectric behavior of CuO containing glasses, since no publications concerning this issue have been presented before. Different glasses in the binary Na2O-B2O3 system were prepared by melt annealing technique. XRD spectra have shown that the amorphous structure is dominant in all glasses containing mixed concentrations from CuO and Na2O. The crystalline phases appeared only in glass free from Na2O. The dielectric spectroscopy is applied to shed some light on the conduction mechanisms in terms of changing both the dielectric constant and the electrical modulus of the investigated glasses. The ac conductivity increases with increasing frequency and decreases with increasing CuO concentration. Both the dielectric constant and dissipation loss is decreased with increasing frequency. Correlated barrier hopping (CBH) is considered an appropriate conduction mechanism results from the increase of frequency.
Monique Tohoue Tognonvi, Arezki Tagnit-Hamou, Léon Koffi Konan, Ablam Zidol, Wilfried Cyrille N’Cho
New Journal of Glass and Ceramics, Volume 10, pp 29-44; doi:10.4236/njgc.2020.103003

The reactivity of the recycled glass powder (GP) in a cementitious medium has been studied over time by means of X-ray diffraction and thermal gravimetric analysis. Two different mixtures based on cement/glass powder (0 or 20 wt% GP) and lime/glass powder (70 wt% GP) were considered. Analysis revealed the coexistence of both hydration and pozzolanic reaction during the hardening of the mortars. At young age, the cement hydration would prevail over the pozzolanic one resulting in a decrease of physico-chemical and mechanical properties of the material due to the dilution effect. The pozzolanic reaction that predominates from 91 days, would induce the formation of supplementary C-S-H leading to improve the material properties.
Kofi Asante-Kyei, Alexander Addae, Mercy Abaka-Attah
New Journal of Glass and Ceramics, Volume 9, pp 50-65; doi:10.4236/njgc.2019.93005

In Ghana, most farmers are peasants and at times foodstuffs produced get rotten either through transportation or market places. This normally affects the meager income that farmers earn through hard work. Available statistics indicate that each year, food crops worth several hundreds of dollars go waste in the country due to poor harvest losses and it represents 70% of total food production in Ghana. Again, in the country, there is abundant of clay as a natural resource. Geological study has revealed that it is found in almost every part of the country. As a means of finding solution to the rate at which local foodstuffs especially plantain rot, the study sought to design and compose clay container purposefully for storing plantain to prolong its lifespan. The study focused on 5 clay body compositions (C1 to C5) and fired at 950°C. Composition C1 consisted of 50% of Abonko clay and 50% of Daboase clay. Composition C2 was made up of 40% Abonko clay, 50% Daboase clay and 10% of smooth sawdust. Composition C3 composed of 45% of Abonko clay, 45% of Daboase clay and 10% of smooth sawdust. Composition C4 was made up of 90% Daboase clay and 10% rough sawdust. The last composition C5 comprised mainly 100% Abonko clay. Fresh plantains obtained from Takoradi market circle were stored in the containers and weekly recordings of states of plantain for five consecutive weeks were carried out. It was revealed that C4 was successful in storing fresh plantains to ripe stage after the five weeks. It is recommended among others that, the technique should be made available to stakeholders such as Ministry of Food and Agriculture (MOFA), plantain farmers and market plantain sellers through seminars, public education and symposia in order to minimize post-harvest losses.
A. Behairy
New Journal of Glass and Ceramics, Volume 9, pp 15-24; doi:10.4236/njgc.2019.92002

Hicham Es-Soufi, Lahcen Bih, Meyrem Benzineb
New Journal of Glass and Ceramics, Volume 9, pp 33-49; doi:10.4236/njgc.2019.93004

Glasses of the compositions 20Li2O-(50 - x)Li2WO4-xFe2O3-30P2O5 where (x = 0, 1, 5, 8, 10, 15 mol%) were elaborated by the melt-quenching route. Synthesized glasses are characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetric (DSC), and density determination. The XRD patterns confirmed the amorphous nature of samples, and IR spectra showed the structural groups and highlight the depolymerization of phosphate network with the introduction of iron oxide. It is found that the structural unit Q2 converts to Q1 and Q0 as Fe2O3 replaces Li2WO4. Chemical durability tests on the glasses have shown that the compositions containing pyrophosphate (Q1) and orthophosphate (Q0) units are more water-resist. The electrical conductivity measurements were performed by complex impedance spectroscopy in the frequency range of 20 - 106 Hz at various temperatures from ambient to 400°C. It is found that the conductivity is activated thermally and follows an Arrhenius law. The obtained electrical data were analyzed by the modulus formalism and dielectric formalism. The determined asymmetric nature of spectra suggested that the relaxation behavior is non-Debye and characterized by the stretched exponent parameter β
Nissamuddeen Kunnath, Jacob Philip
New Journal of Glass and Ceramics, Volume 9, pp 1-14; doi:10.4236/njgc.2019.91001

Potassium Sodium Bismuth Titanate (KNBT) ceramics, with the general formula (1 - x)K0.5Bi0.5TiO3 -xNa0.5Bi0.5TiO3, have been synthesized following hydrothermal route, starting with solid solutions of pure perovskite nanoceramics of KBT and NBT in desired stoichiometric weight ratios, followed by sintering between 850°C and 1000°C for few hours. Pure KNBT nanoceramics with perovskite structure, having mean particle size around 30 nm, could be obtained. Morphology of the samples is found to depend strongly on composition. A change of composition results in a phase change, as evident from X-ray structure analysis. This phase change is a result of rhombohedral to tetragonal morphotropic phase boundary (MPB) in the sample with x around 0.80. Composition dependent occurrence of MPB leads to formation of needle like structures with micrometer length scales. These are typical of tetragonal lamellar structures, suggesting partial induction of tetragonal polar order from rhombohedral structure at MPB. Dielectric and piezoelectric properties, such as dielectric constant and loss, piezoelectric coefficients and figures of merit, exhibit threshold maxima in their values at the composition corresponding to MPB. These values reported for a lead-free piezoceramic, synthesized by a comparatively simple hydrothermal route, are highly promising, and comparable to well-known PZT.
Jianhua Zhu, Jinyuan Liu, Songjie Lu, Yong Zeng, Zhu Jianhua, Liu Jinyuan, Lu Songjie, Zeng Yong
New Journal of Glass and Ceramics, Volume 9, pp 25-32; doi:10.4236/njgc.2019.93003

The sintering temperature of Li2ZnTi3O8 ceramics is still high for LTCC-based applications. In this work, V2O5 was doped as the sintering aid. The sintered density, phase composition, grain size, as well as microwave dielectric properties of Li2ZnTi3O8 ceramics with the addition of V2O5 were investigated. Based on our research, V2O5 doping effectively promoted the densification of Li2ZnTi3O8 ceramics at about 900°C, without affecting the main crystal phase of the ceramics. Li2ZnTi3O8 ceramics with 0.5 wt% V2O5 doping (sintered at 900°C) exhibited the best microwave dielectric properties (Qf = 22,400 GHz at about 6 GHz, εr = 25.5, and τf = -10.8 ppm/°C). The V2O5-doped Li2ZnTi3O8 ceramics were well cofired with Ag inner paste without cracks and diffusion, indicating its significant potential for LTCC applications.
Gomaa El Damrawi, Amal Behairy, Riham Atef, El Damrawi Gomaa, Behairy Amal, Atef Riham
New Journal of Glass and Ceramics, Volume 9, pp 67-79; doi:10.4236/njgc.2019.94006

Glass and Glass iomomer cement (GICs) based on a specific composition of cerium phosphate glass (40 CeO2-60P2O5) have been prepared. Effect of the doping type at a fixed doping concentration from metal-phthalocyanines (M-PCs) on material structure and morphologies has been carefully studied. The corresponding changes in the material structure were widely followed up by 31P MAS NMR, X-Ray diffraction and FTIR spectroscopy. The network structure of both base glass and GIC which all free from metal phthalocyanines has been confirmed to be amorphous. GIC doped with M-PCs has shown a more ordered structure. There were clear changes in the position and intensities of 31P NMR spectral peaks of glasses upon changing the dopant type. In all cases, a little concentration from M-Phthalocyanine (0.8 mol%) leads to changing the network structure from amorphous to a more ordered structure. Phosphate structural phases are evidenced to be formed upon addition of a fixed amount of M-PCs (Ga, Co, Fe). The morphologies of some selected samples were characterized by SEM. The micrographs have revealed that formulating of cerium phosphate powder of the amorphous glass with a polymeric acid successfully led to the formation of CePO4-H2O bundles phases. But formulation with GIC containing Co or Fe or Ga Phthalocyanine can simply form co-aligned linear slaps and elongated nanofibers which are consisted of hydrated and carbonated CePO4 a GaPO4, FePO4 or CoPO4 crystals. The structure of all doped materials has a lower crack length than that of base glass. This was discussed on bases of formation of more aligned and elongated tough-fibers in matrix of all doped materials. Such tough fibers have ability to withstand breaking stress via suppressing crack propagation.
Gomaa El-Damrawi, Fawzeya Gharghar, Rawya Ramadan
New Journal of Glass and Ceramics, Volume 8, pp 12-21; doi:10.4236/njgc.2018.81002

The structure of glasses in the system of xCeO2(100 − x)B2O3, x = 30, 40, 50 mol% CeO2 has been explored for the first time by correlation between data obtained from XRD, FTIR and 11B NMR analyses. NMR spectroscopy and FTIR spectroscopy have confirmed that transformation rate of BO3 to BO4 groups is reduced by CeO2 addition. The concentration of Ce4-O-Ce4 is increased at the expense of both B4-O-Ce4 and B3-O-B4 linkages. Boron atoms are mainly coordinated with Ce4 sites as second neighbors due to increasing CeO4 species with further increase of CeO2 concentration. Increasing B4 fraction is considered due to forming of CeO4 with rate higher than that of BO4 units. The change of chemical shift of 11B nuclei upon exchanging B2O3 with CeO2 confirms that the central boron atoms would be coordinated with tetrahedral cerium atoms as second neighbors. The X-ray diffraction of cerium rich glass is clearly indicated that the formation of crystalline phases refers to CeO4, CeBO3 and Ce(BO2)3 species.
Gomaa El-Damrawi, Amal Behairy, Amr M. Abdelghany
New Journal of Glass and Ceramics, Volume 8, pp 23-38; doi:10.4236/njgc.2018.82003

Cerium Pyrophosphate glass is prepared and investigated by different structural techniques. Resin modified glass ionomer cements (RGICs) of pyro cerium phosphate (40CeO2-60P2Os) composition doped with different concentrations from GaCl Phthalocyanine (C32H16ClGaN8) have been also prepared and studied for the first time. Different techniques have been applied to shed light on the structural changes induced upon addition of GaCl-Phthalocyanine. The corresponding changes in material structure are widely approved by results of 31P magic angle spinning nuclear magnetic resonance (MAS-NMR), X-Ray diffraction and FTIR spectroscopy. The network structure of both base glass and GIC free from C32H16ClGaN8 is confirmed to be amorphous. Doping even with little concentration from GaCl-Phthalocyanine leads to changing the network structure from amorphous to a highly crystalline one. Formulation of GaCl-Phthalocyanine with water soluble acid leads to monocrystalline structure due to monoclinic lattice structure of Phthalocyanine. Carbonated hydroxyl cerium and gallium phosphate structural phases are evidenced to be formed upon GaCl-Phthalocyanine addition. Presence of such bioactive phases can support that the prepared GICs of considerable C32H16ClGaN8 concentration (1 and 1.5 mol%) can be applied as biocompatible materials used in biodental applications. The morphologies of some selected samples were characterized by SEM. The micrographs have revealed that formulating of cerium phosphate powder of the amorphous glass with polymeric acid successfully led to the formation of CePO4-H2O nanofibrous bundles. But formulation with GIC containing GaCl-Phthalocyanine can simply form co-aligned and elongated nanofibers (15 - 40 nm thick and up to ca. 1.2 m long). The formed nanofibers are mainly consisted of hydrated and carbonated CePO4 and GaPO4 nanocrystals. The hardness of the cemented material increases with increasing GaCl-Phthalocyanine concentrations.
Marie Leteve, Norbert Passuti
New Journal of Glass and Ceramics, Volume 8, pp 39-54; doi:10.4236/njgc.2018.83004

Purpose: Bone grafting is still requested to fill bone defects in traumatology, or after tumor removal, but also in orthopedic surgery for spine, arthroplasty revisions, and osteotomies. Due to the limitations of autografts and allografts, and the progress of biomaterial research, a large number of nonhuman bony scaffolds have been developed including synthetic calcium phosphates and highly processed xenografts. The most important parameters for bone ingrowth are the macroporosity of the scaffold with the suitable biological autologous cells and factors, optimal osteoinductive, osteointegrative and osteoconductive properties can be achieved. Methods and Results: The important factors regulating these properties are discussed in this paper, which also reports preclinical and clinical results obtained with such bone graft substitutes. Conclusions: Among different bone graft substitutes available, the porosity, the accessibility of pores, the internal surface exposed to the biological components of bone repair, are present in highly processed bovine hydroxyapatites. Compared to autografts, allografts and synthetic substitutes, they associate an initial conductivity, and a long term stability suitable for some orthopedic indications.
Florian Senn, Ronald Holtz, Sonja-Michaela Gross-Barsnick, Uwe Reisgen
New Journal of Glass and Ceramics, Volume 8, pp 1-11; doi:10.4236/njgc.2018.81001

An ultra-fast laser with central wavelength at 1064 nm and 10 ps pulse duration was used to tightly focus laser radiation with a microscope objective inside the volume of nucleated Lithium Aluminosilicate (LAS) glass-ceramic. The nonlinear absorption of the LAS glass-ceramic was measured for different laser parameters and a thermal simulation was performed to determine the temperature field inside the laser-modified area. After laser processing, the samples were crystallized in a furnace and the effect of the laser-induced modifications on the microstructure was analyzed with SEM. The SEM analysis shows an increase in the length and size of whisker-shaped β-spodumene crystals in the laser-modified area. By increasing the dimension of these whisker-shaped crystals, the flexural strength of LAS can be improved locally. First four-point bending flexural tests were performed to examine the influence on the mechanical properties.
Tai-Chun Han, Chun Yen, Yi-De Chung, Meng-Lin Wu
New Journal of Glass and Ceramics, Volume 08, pp 55-63; doi:10.4236/njgc.2018.84005

This article aims to investigate the possibility to turn the multiferroic orders and magnetocapacitance effect close to/above room temperature in nanosized GaFeO3 ceramics by a sol-gel preparation method and substitution with non-magnetic Zn atoms. Therefore, in this work, we have synthesized a series of nanocrystalline Ga1-xZnxFeO3(GZFO, x = 0, 0.01, 0.05 and 0.1) ceramic samples and study the effect of Zn substitution on their structural, magnetic, and electric properties. All the GZFO samples have an orthorhombic structure with Pc21n space group and the value of lattice parameters increase systematically with increasing Zn concentration. Interestingly, it shows that magnetic and electric properties are strongly dependent on the Zn substitution concentration. Based on the results of temperature-dependent magnetizations, M(T), it is observed that with increasing Zn-content up to 0.10, the ferrimagnetic transition temperature (TC) increases from 306 to 320 K. It is also found that the nanocrystalline Zn-doped GaFeO3 (GFO) samples exhibit the characteristics of ferroelectricity at room temperature. Furthermore, the magnetization, ferroelectric polarization and magnetocapacitance of Zn-doped GFO nanosized ceramics are enhanced compared to those of the pristine sample of GFO ferrite. These results open wide perspectives for the applications of room temperature multiferroic devices.
Gomaa El-Damrawi, Abdel Meguid Hassan, Sammer El-Jadal
New Journal of Glass and Ceramics, Volume 7, pp 13-21; doi:10.4236/njgc.2017.72002

Gomaa El-Damrawi, Abdelmeguid K. Hassan, Salma Ehmead, Amal El Shahawy
New Journal of Glass and Ceramics, Volume 7, pp 22-33; doi:10.4236/njgc.2017.72003

Ravinder Singh, , Gurmel Singh, Kulwant Singh Thind
New Journal of Glass and Ceramics, Volume 7, pp 1-11; doi:10.4236/njgc.2017.71001

Khadijah M. Al Mokhtar, Bahia O. Alsobhi
New Journal of Glass and Ceramics, Volume 7, pp 91-99; doi:10.4236/njgc.2017.74008

Ga80-xSexTe20 amorphous system was prepared by conventional technique. Structural, morphology and optical properties have been investigated. X-ray diffraction (XRD) patterns reveal the non-crystalline nature of the prepared sample. Differential thermal analysis (DTA) traces indicate the presence glass transition temperature Tg for all samples below 500°C. Addition Tg values increases by increasing Se content. Energy dispersive X-ray spectroscopy (EDX) data shows good agreement with actual composition. Moreover, surface characterization was achieved by scanning electron microscope (SEM). The patterns confirmed the non-crystalline nature. In order to analyze the data, the cohesive energy C.E was calculated by all three composition optical properties that have been investigated in the wavelength range 500 - 2500 nm. Reflectivity R and transmitivity T spectrum were used to estimate the band gap energy using UV-Visible absorption spectrum. It is worthy mention that the optical band gap follows the Tg and cohesive energy behavior, where it increases by increasing Se content.
Shunichi Kaneko, ,
New Journal of Glass and Ceramics, Volume 7, pp 58-76; doi:10.4236/njgc.2017.73006

We conducted structural analysis of xNa2O-yY2O3-5B2O3-3Al2O3 and xNa2O-yLa2O3-5B2O3-3Al2O3 glasses to elucidate the additive effects of rare-earth ions in these sodium aluminoborate glasses, and investigated the local environment surrounding Na+ in them by using 23Na and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The amount of higher-coordinated Al species ([5]Al and [6]Al) gradually increased in response to an increase in the ratios of Y2O3 to Al2O3 and La2O3 to Al2O3 in each type of glass, respectively. Moreover, the difference in the cation field strength (CFS) between Y3+ and La3+ was observed to affect the generation of [5]Al and [6]Al, especially when the amount of these ions in the glasses increased. In addition to the above, the coordination number of Na+ ions increased with an increase in the number of rare earth ions, confirmed by comparing results with NMR spectra of crystalline Na2Al2B2O7. The latter possibly occurred due to the oxygen concentration on Al[5] and Al[6]. Finally, it was confirmed that the formation of [5]Al and [6]Al decreases molar volume in oxide glasses, which might be partially due to better atomic packing of [5]Al and [6]Al.
P. Tejeswararao, D. L. Sastry
New Journal of Glass and Ceramics, Volume 7, pp 49-57; doi:10.4236/njgc.2017.73005

Temperature dependent DC electrical conductivity studies of GeO2 substituted lead vanadate glass systems xGeO2(50-x)PbO:50V2O5 (x = 5, 10, 15 mole%) were carried out and the results are reported. X-ray diffraction results reveal that all samples are perfect amorphous in nature. DSC results indicate that the substituent GeO2 is replacing PbO in the glass network in such a way that the eutectic composition is maintained. DC electrical conductivity studies of the glass samples indicate that the systems are characterized by different activation energies in different temperature ranges which in turn depend on the annealing temperature. These results are interpreted in terms of temperature dependent microstructural changes in these glass systems.
Gomaa El-Damrawi, Abdelmajued Hassan, Hamdy Doweidar, Ahamed Shaboub
New Journal of Glass and Ceramics, Volume 7, pp 77-89; doi:10.4236/njgc.2017.73007

Silver phosphate glasses of general formula xAg2O·(100 - x)P2O5 have been investigated over compositional range from x = 40 to 62.5 mol%. The local structure around phosphorus atom has been studied via 31P nuclear magnetic resonance. The distribution of [PO4]Qn species as a function of composition has been shown to slightly deviate from the simple binary alkali phosphate model. An anomalous behavior has been recorded and interpreted in terms of mixed ring-chain effect in metaphosphate composition. The splitting of NMR spectra into sub resonances is assigned to different binding sites characterizing Q1 ring and Q1 chain structure. Higher Ag2O concentration (≥50 mol%) leads to formation of phosphate groups with specific resonance peaks which are mainly related to pyro and orthophosphate species. The rate of change of the chemical shift of the 31P NMR depends on the bond type, which in turn reflects the extent of double bonding between phosphorus and oxygen atoms. Increasing concentration of Q0 with increasing Ag2O content leads to decreasing quantities of bridging and double bonds. As a consequence, specific symmetric resonance peak of higher intensity and chemical shift (Q0) is a feature of silver rich glasses (orthophosphate). The latter species is therefore proposed to compose of separated membered rings, which cause deshielding of phosphate units. XRD and EDP studies have shown that, amorphous phosphate network is the dominant structure of glasses containing ≤ 55 mol% Ag2O. Some ordered and well crystallized phases are formed at higher Ag2O concentration. Increasing non-bridging oxygen atoms is shown to have the main effect on crystallization behavior. Orthophosphate composition is the most crystalline one among the other compositions (ultra, meta- and pyrophosphate). Presence of orthophosphate species which typically contains highest concentration from isolated Q0 units is the main reason for building up crystalline Ag3PO4phosphate phase.
Chenkai Zhu, Jinsong Liu, Songling Huang, Lizhe He, Xiaoye Cong, ,
New Journal of Glass and Ceramics, Volume 7, pp 100-115; doi:10.4236/njgc.2017.74009

Currently, phosphate based glasses have been potential future biomaterial for medical application due to excellent cytocompatibility and fully bioresorbability. In this study, phosphate based glass system with composition of 48P2O5-12B2O3-(25-X)MgO-14CaO-1Na2O-(X)Fe2O3 (X = 6, 8, 10) and 45P2O5-(Y)B2O3-(32-Y)MgO-14CaO-1Na2O-8Fe2O3 (Y = 12, 15, 20), was prepared via a melting quenching process. The effect of replacing MgO with Fe2O3 and B2O3 on the structural, thermal, degradation properties of phosphate based glass was investigated. Fourier Transform Infrared (FTIR) spectroscopy and Raman spectroscopy analysis confirmed the polymerisation of phosphate based glass network with addition of Fe2O3, thus the processing window was observed to increase whilst the dissolution rate was reduced, attributed to the formation of Fe-O-P cross-link. As the effect on the glass structure stability was demonstrated by both B2O3 and MgO, the nonlinear variation of thermal stability and degradation behaviour was observed for glass system with substitution of MgO by B2O3. However, due to the lower dissolution rate of glass system when compared to the biocompatible phosphate based glass in preliminary study, the expected cytocompatibility could be confirmed in the downstream activities.
S. El Kalakhi, A. Samdi, , M. Gomina
New Journal of Glass and Ceramics, Volume 6, pp 28-36; doi:10.4236/njgc.2016.63004

, Abdelkarim Maaroufi, Bruno Lucas, Aumeur El Amrani
New Journal of Glass and Ceramics, Volume 6, pp 19-27; doi:10.4236/njgc.2016.63003

Gomaa El-Damrawi, Abdel Meguid Hassan, Rawia Ramadan, Sammer El-Jadal
New Journal of Glass and Ceramics, Volume 6, pp 47-56; doi:10.4236/njgc.2016.64006

Beena Bhatia, S. L. Meena
New Journal of Glass and Ceramics, Volume 6, pp 9-17; doi:10.4236/njgc.2016.62002

Glass sample of Zinc Lithium Bismuth Borate (25-x) Bi2O3:20Li2O:20ZnO:35B2O3:xPr6O11, (where x = 1, 1.5 and 2 mol%) has been prepared by melt-quenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. The absorption spectra of three Pr3+ doped zinc lithium bismuth borate glasses have been recorded at room temperature. The observed optical spectra are discussed in terms of energy states and the intensity of the transitions. The various interaction parameters like Slater-Condon, Lande, bonding and Racah parameters have been computed. Judd-Ofelt intensity parameters and laser parameters have also been calculated. The stimulated emission cross section (σp) for the transition (3P0 → 3F2) is found to be in the range 3.12 - 10.43 * 10-20 cm2. The σp values are comparatively large suggesting the possible utilization of these materials in laser applications.
Gomaa El-Damrawi, Fawzia Gharghar, Rawia Ramadan, Mohamed Aboelez
New Journal of Glass and Ceramics, Volume 6, pp 57-63; doi:10.4236/njgc.2016.64007

, Yoh Katoh
New Journal of Glass and Ceramics, Volume 5, pp 25-30; doi:10.4236/njgc.2015.53004

Beena Bhatia, S. L. Meena, Vishal Parihar, Monika Poonia
New Journal of Glass and Ceramics, Volume 5, pp 44-52; doi:10.4236/njgc.2015.53006

Austine A. Mulama, Julius M. Mwabora, Andrew O. Oduor, Cosmas M. Muiva, Boniface Muthoka, Betty N. Amukayia, Drinold A. Mbete
New Journal of Glass and Ceramics, Volume 5, pp 16-24; doi:10.4236/njgc.2015.52003

Ponnada Tejeswara Rao, Balireddy Vasundhara
New Journal of Glass and Ceramics, Volume 5, pp 53-58; doi:10.4236/njgc.2015.53007

Inas Kamal Batttisha, Ibrahim Sayed Ahmed Farag, Mostafa Kamal, Mohamed Ali Ahmed, Emad Girgis, Fawzi El Desouki, Hesham Azmi El Meleegi
New Journal of Glass and Ceramics, Volume 5, pp 59-73; doi:10.4236/njgc.2015.53008

Nafissa Khennafi-Benghalem, Walid Allag
New Journal of Glass and Ceramics, Volume 5, pp 75-83; doi:10.4236/njgc.2015.54009

The aim of this work is to study in detail the drilling process on glass by CO2 laser. The study parameters considered in the present experiments are based on the laser beam power of range (30% - 80% of 25 W) and an exposure time for drilling (2 - 8 s). The measured diameters of holes by optical methods are between [300 - 800 μm]. The results obtained by optical observations suggest that ordinary and mineral glasses cannot withstand to a contact of the laser beam and crack during the formation of the drilling hole. The minimum power and duration of exposure are the optimal parameters for drilling the organic glass, we observe no micro-cracks, and again we see that the edges of the holes have a good surface quality with a high aspect ratio.
, QingYou Zhu, Chengji Deng,
New Journal of Glass and Ceramics, Volume 5, pp 1-7; doi:10.4236/njgc.2015.51001

Inas Kamal Batttisha, Ibrahim Sayed Ahmed Farag, Mostafa Kamal, Mohamed Ali Ahmed, Emad Girgis, Hesham Azmi El Meleegi, Fawzi Gooda El Desouky
New Journal of Glass and Ceramics, Volume 4, pp 19-28; doi:10.4236/njgc.2014.42003

Shipra Saraswat, Surendra Dutt Sharma
New Journal of Glass and Ceramics, Volume 4, pp 66-71; doi:10.4236/njgc.2014.44009

Deepak Sharma, Anand Mohan Awasthi
New Journal of Glass and Ceramics, Volume 4, pp 38-41; doi:10.4236/njgc.2014.42005

José Antonio Alves Júnior, João Baptista Baldo
New Journal of Glass and Ceramics, Volume 4, pp 29-37; doi:10.4236/njgc.2014.42004

Radhouane Bel-Hadj-Tahar, Abdellatif Belhadj Mohamed
New Journal of Glass and Ceramics, Volume 4, pp 55-65; doi:10.4236/njgc.2014.44008

Yomei Tokuda, Hiroaki Matsuki, Yoshikatsu Ueda, Hirokazu Masai, Toshinobu Yoko
New Journal of Glass and Ceramics, Volume 4, pp 49-54; doi:10.4236/njgc.2014.43007

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