Method of Fabricating Ceria-Stabilized Tetragonal Zirconia Polycrystals

Most zirconia-based toughened ceramics need specialized processes to achieve their desired properties. In this paper, we report the fabrication of toughened ceria-stabilized tetragonal zirconia polycrystal by conventional processing, i.e., ball milling and cold-pressing followed by sintering. We believe that ball milling works here because a somewhat coarser particle size is actually beneficial in this case. Although the samples were not fully dense (they need not be), a composition of ZrO₂-12 mol% CeO₂ yielded a fracture toughness value of 14.1 MPa·m^1/2. This is comparable to values reported for materials processed by specialized techniques and can be rationalized in terms of R-curve behavior.     

Microprobe analysis of the corroded surface of a silicate glass

A soda lime silicate sheet glass was corroded in acid (pH = 0) and alkaline (pH = 11) aqueous solutions at 30±1° C for various lengths of time. The concentration profile of CaO and SiO₂ within the leached layer was estimated with electron microprobe analysis. Formation of a silica rich layer at a depth of about 10 μm from the bare surface followed by a calcium rich-layer, which again in some cases is followed by silica rich and calcium rich layers, were observed. The number and intensity of these layers changed with the pH value of the corroding solution, and at the same pH value changed with time of leaching.     

Review on potential non-dairy synbiotic beverages: a preliminary approach using legumes

In the past few years, certain functional foods have gained consumer acceptance like those containing synbiotics (a blend of both prebiotics and probiotics) in different food systems. Synbiotics enhance gut functionality and confer health benefits to humans. However, due to the limitations exerted by dairy-based matrices like lactose intolerance, milk allergies, limited shelf life and inclination towards veganism, consumer’s interest in non-dairy foods has increased. Among the non-dairy matrices, legumes (such as chickpeas, kidney beans, lupin) are the less explored areas with the majority focus on only soya beans. The present review gives brief information about the different research associating with various legume-based probiotics, prebiotics and synbiotic foods narrowing down specifically to beverages. The integration of such information will allow the researchers to explore product development using new prebiotic ingredients that have not been studied in much detail and hold an exceptional potential to be employed in the synbiotic food industry.     

Reliability of linear structures with parameter uncertainty under non-stationary earthquake

The present work aims towards the development of a general framework of time varying unconditional reliability evaluation of linear elastic multi degree of freedom structures with uncertain parameter subjected to the generalized earthquake ground motion, a non-stationary process both in amplitude and frequency content. The formulation is developed in double frequency spectrum to derive the generalized power spectral density function of the structural responses. The time varying reliability is evaluated using conditional crossing rate following the Vanmarcke’s modification. The perturbation based stochastic finite element method is utilized in deriving unconditional reliability. An idealized three dimensional dam structure subjected to El Centro (1940) earthquake is taken up to elucidate the proposed unconditional time varying reliability computation procedure based on the maximum top displacement and base shear criteria. The results are presented to compare the change in reliabilities of the uncertain system with that of deterministic system and associated variance of the reliability due to parameter uncertainty.     

Arsenic levels in drinking water and the prevalence of skin lesions in West Bengal, India

OBJECTIVE: To evaluate the suitability and efficiency of human follicular fluid (HFF) as a protein supplement in human IVF programs. DESIGN: Comparative study of the effects of HFF and other protein supplements on the in vitro development of mouse oocytes and on the pregnancy rate in human IVF programs. SETTING: In Vitro Fertilization Center, Hanna Women's Clinic, Seoul, Korea. PATIENT(S): Three hundred twenty-seven patients (388 cycles) who were down-regulated with GnRH agonist and stimulated with hMG. INTERVENTION(S): The suitability was evaluated with the results of animal studies and the efficiency of HFF was investigated with the results of human IVF programs. MAIN OUTCOME MEASURE(S): Meiotic maturation of mouse oocytes, development of mouse embryos, morphological grades of human embryos, pregnancy rate in human IVF programs, and electrophoresis. RESULT(S): Human follicular fluid significantly stimulated meiotic resumption in mouse oocytes, even in the presence of meiotic inhibitors, and enhanced the developmental potential of mouse embryos in vitro. Compared with human fetal cord serum, human follicular fluid also improved the morphological grade of human embryos by reducing cytoplasmic fragmentation. In conventional IVF cycles of human IVF programs, use of HFF significantly increased the clinical PR (109/234 cycles, 46.5%; P < .05), compared with use of human fetal cord serum (14/52 cycles, 26.9%). However, in intracytoplasmic sperm injection cycles, there was no difference in PRs between use of HFF (38/85 cycles, 44.7%) and use of human fetal cord serum (7/17 cycles, 41.1%). When the protein compositions of human fetal cord serum and HFF were investigated by electrophoresis, a protein of 21 kD was detected specifically in HFF. CONCLUSION(S): Human follicular fluid is suitable for use as a protein supplement and is effective in increasing the pregnancy rate in human IVF programs.     

Electron holographic characterization of ultra-shallow junctions in Si for nanoscale MOSFETs

This investigation attempts quantitative characterization of ultra-shallow junctions (USJs) in Si, useful for future generations of nanoscale MOSFETs as predicted by the Semiconductor Industry Association Roadmap. The USJs were fabricated using rapid thermal diffusion (RTD) from a heavily doped n-type surface source onto a heavily doped p-type substrate. The dopant profiles were analyzed using secondary ion mass spectrometry (SIMS), and were further used to calculate the metallurgical junction depth (MJD). One-dimensional (1-D) characterization of the electrical junction depth (EJD) associated with the electrically activated fraction of the incorporated dopants was performed using off-axis electron holography in a transmission electron microscope. 1-D potential profiles were derived from the unwrapped phase of the reconstructed holograms. The EJD was derived from the measured potential distribution across the p-n junction, and quantitative comparison is made with MJD derived from the SIMS profiles. The comparison between calculated electric field and total-charge distributions from the measured potential profiles and the simulated distributions using the SIMS profiles provides a quantitative estimate of the electrical activation of dopants incorporated by the RTD process, within the accuracy limits of this technique, which is discussed herein.     

Electrical conductivity and electromagnetic interference shielding effectiveness of polyaniline–ethylene vinyl acetate composites

Electrical conductivity and electromagnetic interference (EMI) shielding effectiveness at microwave (200–2000 MHz) and X‐band (8–12 GHz) frequency range of polyaniline (PAni) composites were studied. It has been observed that EMI shielding of conductive polyaniline (PAni)–ethylene vinyl acetate composites increases with the increase in the loading levels of the conductive polymer doped with dodecylbenzene sulfonic acid. The result indicates that the composites having higher PAni loading (>23%) can be used for EMI shielding materials and those with lower PAni loading can be used for the dissipation of electrostatic charge. Copyright © 2004 Society of Chemical Industry     

Fluid Flow in a Tundish Optimized through Genetic Algorithms

The fluid flow in a continuous casting tundish is computed for an optimum parameter setting such that the stresses produced at the walls get minimized. This optimization task is carried out using a Genetic Algorithms based procedure that worked in tandem with a 3‐D transient Navier‐Stokes equation solver. The fluid flow equations are iteratively solved by using a pressure‐based finite volume method, according to the SIMPLER algorithm. The k‐ε model is used for achieving the turbulence closure. The numerical simulations reveal how the Genetic Algorithm can be effectively used for optimizing the fluidic design of the tundish.     

Allergenic relationship among four common and dominant airborne palm pollen grains from Eastern India

BACKGROUND: Palm pollen grains are predominant aeroallergens in the tropics including India. Evidence of allergenic crossreactivity had been reported from various parts of the world on different families, e.g. Poaceae, Asteraceae, etc. No such information is available about the palm pollen of tropical countries. OBJECTIVES: The present study was undertaken to find out the allergenic relationship, if any, in four common and important palm pollen in India. METHODS: A 2-year aerobiological survey was carried out at Madhyamgram situated at the suburban fringe of Calcutta Metropolis using Burkard volumetric sampler to know the seasonal variation of Areca catechu, Borassus flabellifer, Cocos nucifera and Phoenix sylvestris among others. Skin-prick tests (SPT) were performed with the relevant pollen extracts on the respiratory allergic patients. Sera from the subjects were tested directly by ELISA for estimating the allergen specific IgE. ELISA inhibitions and dot blotting were performed with pooled patients sera and four palm pollen extracts to detect the cross-reactivity. RESULTS: Among 70 patients, Areca catechu exhibited the maximum percentage (48.5%) of positive responses followed by Cocos nucifera (45.7%), Phoenix sylvestris (42.85%) and Borassus flabellifer (38.5%). On an average, 30-50% of the patients showed positive skin reactions and enhanced specific IgE level to more than one palm pollen extract. Further evidence of allergenic crossreactivity among the four palm pollen grains were provided by dot blotting and ELISA inhibition studies. In ELISA inhibition, a distinct inhibition was obtained with comparable amounts of the pollen extracts. CONCLUSION: The suburban aerobiological survey of Calcutta and SPT results confirmed that the relevant pollen types are significant contributors of aeroallergen load of the study area. ELISA inhibition studies with the pooled patients sera using antihuman IgE probe revealed the presence of shared allergenic components among the four palm pollen grains.