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51.
Among various coating systems for industrial and engineering applications, glass and glass-ceramic coatings have advantages
of chemical inertness, high temperature stability and superior mechanical properties such as abrasion, impact etc as compared
to other coating materials applied by thermal spraying in its different forms viz. PVD, CVD, plasma, etc. Besides imparting
required functional properties such as heat, abrasion and corrosion resistance to suit particular end use requirements, the
glass and glass-ceramic coatings in general also provide good adherence, defect free surface and refractoriness.
Systematic studies covering the basic science of glass and glass-ceramic coatings, the functional properties required for
a particular end-use along with the various fields of application have been reviewed in this paper. 相似文献
52.
Single crystals of MgO were subjected to plastic strain-controlled push-pull cyclic deformation at elevated temperatures. Below 400° C the crystals were very brittle and failed with a few fatigue cycles. At 470° C a large number of cycles could be obtained before failure, and the cyclic stress-strain response showed a period of rapid hardening followed by a period of decreasing hardening rate. TEM investigations of the lower temperature samples show structures of isolated dislocation dipoles, multipoles and debris. At 470° C dense bundles of dislocations were observed aligned perpendicular to the Burgers vector direction. The regions between the bundles were relatively dislocation free, but they contained a high density of debris. Bowed out screw dislocations are observed between the edge dislocation bundles, suggesting that screw dislocations were largely mobile. Comparisons are made with the cyclic deformation and structure of fcc metals and other NaCl structure single crystals. 相似文献
53.
We have studied the hydration of Secar 71 high alumina cement with added poly(vinyl alcohol-acetate). These materials are used in production of macro-defect-free cements. The polymer has considerable effects on the cement chemistry; the heat output profile measured by conduction calorimetry is significantly altered and few crystalline hydrates are produced. Where hydrate crystals do occur, the calcium-rich compounds are preferred. There are some differences in behaviour between pure polyvinyl alcohol and polymers containing acetate groups. Evidence is presented for polymer complexes in which metal ions from the cement crosslink the polymer chains. Such complexes are formed most readily by aluminium ions, so the cement grains are left with a relative surplus of calcium on their hydrating surfaces. 相似文献
54.
Payal Sharma Chetan Sharma Kanchan L. Singh Anirudh P. Singh 《JOM Journal of the Minerals, Metals and Materials Society》2018,70(8):1398-1403
Doped and co-doped ceria ceramics are used as electrolyte materials in solid oxide fuel cells. In this work, ceria-based oxides, Ce0.90Gd0.06Y0.02M0.02O2?δ (M?=?Ca, Fe, La, and Sr) were prepared by conventional as well as microwave processing from the precursors prepared by the mixed oxide method. The consolidated calcined powders in pellet form were sintered in microwave energy at 1400°C for 20 min and in an electric furnace of IR radiation at 1400°C for 6 h. The x-ray diffraction analysis confirmed that all the compositions were crystallized into a cubic fluorite structure. Surface morphology of the sintered products was studied using scanning electron microscopy and the microhardness was investigated using the Vickers hardness test. The comparative results analysis shows that the microwave-sintered samples have uniform grain growth, higher density and higher microhardness than the corresponding conventionally sintered products. The microwave-sintered sample of composition Ce0.90Gd0.06Y0.02Sr0.02O2?δ was found to have the highest microhardness among the four compositions due to its high density and smallest grain size. 相似文献
55.
Steven Blake Samiul Amin Wei Qi Madhabi Majumdar E. Neil Lewis 《International journal of molecular sciences》2015,16(8):17719-17733
A detailed understanding of the mechanism of unfolding, aggregation, and associated rheological changes is developed in this study for β-Lactoglobulin at different pH values through concomitant measurements utilizing dynamic light scattering (DLS), optical microrheology, Raman spectroscopy, and differential scanning calorimetry (DSC). The diffusion interaction parameter kD emerges as an accurate predictor of colloidal stability for this protein consistent with observed aggregation trends and rheology. Drastic aggregation and gelation were observed at pH 5.5. Under this condition, the protein’s secondary and tertiary structures changed simultaneously. At higher pH (7.0 and 8.5), oligomerizaton with no gel formation occurred. For these solutions, tertiary structure and secondary structure transitions were sequential. The low frequency Raman data, which is a good indicator of hydrogen bonding and structuring in water, has been shown to exhibit a strong correlation with the rheological evolution with temperature. This study has, for the first time, demonstrated that this low frequency Raman data, in conjunction with the DSC endotherm, can be been utilized to deconvolve protein unfolding and aggregation/gelation. These findings can have important implications for the development of protein-based biotherapeutics, where the formulation viscosity, aggregation, and stability strongly affects efficacy or in foods where protein structuring is critical for functional and sensory performance. 相似文献
56.
Rongsong Li Zhi Ning Rohit Majumdar Jeffery Cui Wakako Takabe Nelson Jen Constantinos Sioutas Tzung Hsiai 《Particle and fibre toxicology》2010,7(1):1-12
Background
Nanometer silicon dioxide (nano-SiO2) has a wide variety of applications in material sciences, engineering and medicine; however, the potential cell biological and proteomic effects of nano-SiO2 exposure and the toxic mechanisms remain far from clear.Results
Here, we evaluated the effects of amorphous nano-SiO2 (15-nm, 30-nm SiO2). on cellular viability, cell cycle, apoptosis and protein expression in HaCaT cells by using biochemical and morphological analysis, two-dimensional differential gel electrophoresis (2D-DIGE) as well as mass spectrometry (MS). We found that the cellular viability of HaCaT cells was significantly decreased in a dose-dependent manner after the treatment of nano-SiO2 and micro-sized SiO2 particles. The IC50 value (50% concentration of inhibition) was associated with the size of SiO2 particles. Exposure to nano-SiO2 and micro-sized SiO2 particles also induced apoptosis in HaCaT cells in a dose-dependent manner. Furthermore, the smaller SiO2 particle size was, the higher apoptotic rate the cells underwent. The proteomic analysis revealed that 16 differentially expressed proteins were induced by SiO2 exposure, and that the expression levels of the differentially expressed proteins were associated with the particle size. The 16 proteins were identified by MALDI-TOF-TOF-MS analysis and could be classified into 5 categories according to their functions. They include oxidative stress-associated proteins; cytoskeleton-associated proteins; molecular chaperones; energy metabolism-associated proteins; apoptosis and tumor-associated proteins.Conclusions
These results showed that nano-SiO2 exposure exerted toxic effects and altered protein expression in HaCaT cells. The data indicated the alterations of the proteins, such as the proteins associated with oxidative stress and apoptosis, could be involved in the toxic mechanisms of nano-SiO2 exposure. 相似文献57.
58.
We analyze charity requests registered on the Random Acts of Pizza online community and examine the content of postings and non-content characteristics to identify features that are associated with the success of donation. We find that the presence of rational and credible appeals in a message increases the likelihood of receiving a donation, whereas the mere presence of negative emotional appeal does not do so. Our research is useful for those who like to make persuasive charity requests on online platforms. 相似文献
59.
T. J. Majumdar 《International journal of remote sensing》2013,34(11):2207-2208
Thermal inertia is a measure of the resistance power of a material to changes in temperature, and this property of a material is very important from the aspects of hydrological and geological studies. Generation of thermal inertia images and their possible geological application has been attempted over the Indian peninsula and its surroundings using INSAT-1D (Indian National Satellite) VHRR (Very High Resolution Radiometer) day-time and consecutive nighttime data. Using the concepts of energy balance computation and also using the procedures involved in albedo computation and the digital registration of day time and pre-dawn imagery, a thermal inertia map over the whole peninsula and its surroundings has been generated. An attempt has been made to correlate the thermal inertia anomalies with sub-surface structures. The analysis done over the subcontinent shows the possibility of delineation of subsurface structures by thermal inertia mapping. 相似文献
60.
Anindya Chakraborty Arun K. Majumdar Shamik Sural 《International Journal of Information Security》2010,9(1):51-67
Even state of the art database protection mechanisms often fail to prevent occurrence of malicious attacks. Since in a database
environment, the modifications made by one transaction may affect the execution of some of the later transactions, it leads
to spreading of the damage caused by malicious (bad) transactions. Following traditional log-based recovery schemes, one can
rollback (undo) the effect of all the transactions, both malicious as well as non-malicious. In such a scenario, even the
unaffected transactions are also rolled back. In this paper, we propose a column dependency-based approach to identify the
affected transactions which need to be compensated along with the malicious transactions. To ensure durability, committed
non-malicious transactions are then re-executed in a manner that retains database consistency. We present a static recovery
algorithm as well as an on-line version of the same and prove their correctness. A detailed performance evaluation of the
proposed scheme with TPC-C benchmark suite is also presented. 相似文献