Magnetic properties of Hydrogenated Li and Co doped ZnO nanoparticles

The effect of hydrogenation on magnetic properties of Zn0.85Co0.05Li0.10O nanoparticles is presented. It was found that the sample hydrided at room temperature (RT) showed weak ferromagnetism (FM) while that hydrided at 400oC showed robust ferromagnetism at room temperature. In both cases reheating the sample at 400oC in air converts it back into paramagnetic state (P) completely. The characterization of samples by X-ray and electron diffraction (ED) showed that room temperature ferromagnetism observed in the samples hydrogenated at RT is intrinsic in nature whereas that observed in the samples hydrogenated at 400oC is partly due to the cobalt metal clusters.Comment: 10 pages, 3 figure

Coastal versus open-ocean denitrification in the Arabian Sea

International audienceThe Arabian Sea contains one of the three major open-ocean denitrification zones in the world. In addition, pelagic denitrification also occurs over the inner and mid-shelf off the west coast of India. The major differences between the two environments are highlighted using the available data. The perennial open-ocean system occupies two orders of magnitude larger volume than the seasonal coastal system, however, the latter offers more extreme conditions (greater nitrate consumption leading to complete anoxia). Unlike the open-ocean system, the coastal system seems to have undergone a change (i.e., it has intensified) over the past few decades presumably due to enhanced nutrient loading from land. The two systems also differ from each other with regard to the modes of nitrous oxide (N2O) production: In the open-ocean suboxic zone, an accumulation of secondary nitrite (NO2?) is invariably accompanied by depletion of N2O whereas in the coastal suboxic zone high NO2? and very high N2O concentrations frequently co-occur, indicating, respectively, net consumption and net production of N2O by denitrifiers. The extents of heavier isotope enrichment in the combined nitrate and nitrite (NO3?+NO2?) pool and in N2O in reducing waters appear to be considerably smaller in the coastal region, reflecting more varied sources/sinks and/or different isotopic fractionation factors

Calvarial bone defect regeneration using beta-tricalcium phosphate: a translational research study in rat animal model

Background: Guided bone regeneration (GBR) using osteoconductive graft materials has been used for osseous defect healing. The aim of this translational research study was to design and test a critical size calvarial defect (CSD) model in rats, to test GBR with beta-tricalcium phosphate (beta-TCP), using histology and micro computed tomography (micro-CT) assessment.Methods: Female Wistar albino rats (n=10) weighing 300 grams and aged 6-weeks were used and full thickness CSD were created in calvaria following exposure under general anesthesia. CSD were randomly divided into two groups for treatment, based on defect filling material: control group (no graft placed in defect; n=5); and beta-TCP group (defect grafted with beta-TCP; n=5). Both defects were covered with collagen membrane. After 8-weeks of healing the animals were sacrificed and calvarial specimens were subjected to micro-CT and histological assessment.Results: Based on micro-CT the new bone volume (NBV) was significantly higher in beta-TCP group (3.48±0.27 mm3; p<0.05), than control group (2.88±0.33 mm3). Similarly, new bone mineral density (NBMD) was significantly higher in beta-TCP group (0.426±0.018 g/mm3; p<0.01), than control group (0.243±0.015 g/mm3). Histology revealed greater new bone bridging the entire defect with interspersed graft particles in the beta-TCP group.Conclusions: Within the limitations of the present study, GBR of rat calvarial CSD with beta-TCP and collagen membrane, results in significantly higher NBV and NBMD, and is a reliable and reproducible translational research model

Age-Acknowledging Reliable Multiplier Design with Adaptive Hold Logic

Digital multipliers are among the most critical arithmetic functional units. The overall performance of these systems depends on the throughput of the multiplier. Meanwhile, the negative bias temperature instability effect occurs when a pMOS transistor is under negative bias (Vgs = −Vdd), increasing the threshold voltage of the pMOS transistor, and reducing multiplier speed. A similar phenomenon, positive bias temperature instability, occurs when an nMOS transistor is under positive bias. Both effects degrade transistor speed, and in the long term, the system may fail due to timing violations. Therefore, it is important to design reliable high performance multipliers. In this paper, we propose an aging-aware multiplier design with novel adaptive hold logic (AHL) circuit. The multiplier is able to provide higher throughput through the variable latency and can adjust the AHL circuit to mitigate performance degradation that is due to the aging effect. Moreover, the proposed architecture can be applied to a column- or row-bypassing multiplier. The experimental results show that our proposed architecture with 16 ×16 and 32 ×32 column-bypassing multipliers can attain up to 62.88% and 76.28% performance improvement, respectively, compared with 16×16 and 32×32 fixed-latency column-bypassing multipliers. Furthermore, our proposed architecture with 16 × 16 and 32 × 32 row-bypassing multipliers can achieve up to 80.17% and 69.40% performance improvement as compared with 16×16 and 32 × 32 fixed-latency row-bypassing multipliers

Room temperature Ferromagnetism in Th1-xFexO2-d (x = 0.0, 0.05, 0.10, 0.15, 0.20 and 0.25) nanoparticles

Nanocrystalline (Th1-xFex)O2-d particles with different Fe concentrations (x = 0.0, 0.05, 0.10, 0.15, 0.20 and 0.25) have been prepared by a gel combustion method. Rietveld refinement analyses of X-ray diffraction data revealed the formation of an impurity free cubic type Th1-xFexO2-d structure up to x = 0.20. This observation is further confirmed from the detailed studies conducted on 10 at. percent Fe doped ThO2 using high-resolution transmission electron microscopy (HRTEM) imaging and indexing of the selected-area electron diffraction (SAED) patterns. DC Magnetization studies as a function field indicate that they are ferromagnetic with Curie temperature (Tc) well above room temperature.Comment: 10 pages, 5 figure

Community composition of nitrous oxide reducing bacteria investigated using a functional gene microarray

The diversity and environmental distribution of the nosZ gene, which encodes the enzyme responsible for the consumption of nitrous oxide, was investigated in marine and terrestrial environments using a functional gene microarray. The microbial communities represented by the nosZ gene probes showed strong biogeographical separation. Communities from surface ocean waters and agricultural soils differed significantly from each other and from those in oceanic oxygen minimum zones. Atypical nosZ genes, usually associated with incomplete denitrification pathways, were detected in all the environments, including surface ocean waters. The abundance of nosZ genes, as estimated by quantitative PCR, was highest in agricultural soils and lowest in surface ocean waters

High Exhaustion Sytem (HES) for leather process: Role of biocatalyst as an exhaustive aid for wet-end

Content: Application of biocatalyst becomes an imperative due to their eco-friendly advantages. Enzymes in pretanning for unhairing, fiber opening, defleshing and bating are well reported and practiced. However, the role of enzymes as a chemical aids is less explored and consider as a secondary applications. Leather enzymes are known for its hydrolytic behavior which makes it more suitable for pretanning operations. However, typical chemical exhaustive aids acts as a vehicle for the diffusion of chemicals, whereas enzymes aids in the splitting of fibers which facilitate the diffusion of chemicals and create more functional sites for the tanning and post tanning chemicals to interact. In this research, pickled pelts are treated with acid protease and subsequently tanned using chrome tanning agent. Enzymatic treated pelts resulted in better uptake of chromium as compared to conventionally processed leathers. Similarly, after neutralization, chrome tanned leathers are treated with alkaline protease to conventional post tanning has been carried out. Enzymatic treated wet blue leathers showed high uptake of post tanning chemical, uniform dyeing and reduction in the pollution load. From the preliminary research, an interesting finding has augmented that application of enzymes at an optimized concentration, temperature, pH and time would lead to better uptake of chrome which reduces the pollution and minimization pollution load in post tanning. This study, emphasize on the application of enzymes in tanning and post tanning for higher diffusion of chemicals. Take-Away: 1. Replacement of conventional exhaustive aids using biocatalyst 2. Higher exhaustion rate of tanning and post tanning chemicals 3. Futuristic technology for sustainable leather manufactur

Denitrification rates and excess nitrogen gas concentrations in the Arabian Sea oxygen deficient zone

Rates of canonical, i.e. heterotrophic, water-column denitrification were measured by 15N incubation techniques at a number of coastal and open ocean stations in the Arabian Sea. Measurements of N2:Ar gas ratios were also made to obtain independent estimates of N2 excess resulting from denitrification. Measured denitrification rates (15NO3-&#8594;15-14N2) at open ocean stations averaged 9.1&#177;1.0 nmol N l-1 d-1 (n=15), and coastal rates averaged 33.2&#177;12.4 nmol N l-1 d-1 (n=18). When extrapolated to the entire Arabian Sea, deep measurements within the offshore perennial suboxic zone indicate an overall denitrification rate of 41 Tg N a-1&#177;18 Tg N a-1, which is within the range (10-44 Tg N a-1) of previous estimates for canonical denitrification in the region based on stoichiometric calculations and electron transport system activity. Nitrogen excess gas measurements predict a larger nitrogen anomaly than estimated by classical stoichiometric methods (maximum anomaly=23 &#956;g at N l-1 vs. 13 &#956;g at N l-1, respectively). This mismatch may result from incorrect assumptions of Redfield stoichiometry inherent in the nitrate deficit calculation, inputs of new nitrogen through N-fixation, N2 contributions from sedimentary denitrification along continental margins, the anammox reaction, and metal catalyzed denitrification reactions. Nevertheless, if denitrification is defined as the conversion of combined nitrogen to a gaseous end product, then the data suggest that denitrification in the Arabian Sea may have been underestimated so far

Comparative studies on CePO 4 and CeO 2 nanoparticles

Abstract : CePO 4 and CeO 2 nanoparticles were successfully synthesized by reflux method for different reflux timings 6 hrs and 12 hrs. Samples were subjected to Powder XRD, FTIR, SEM, UV-Vis, TG/DTA and PL studies. Powder XRD studies reveal that the crystallite sizes of CePO 4 and CeO 2 nanoparticles increases with increasing reflux time. The crystallite sizes of CeO 2 nanoparticles are smaller than CePO 4 nanoparticles which is evident from the peak broadening in XRD analysis. SEM images show that lots of agglomerations in CeO 2 nanoparticles when compared to CePO 4 nanoparticles. UV-Vis spectral studies indicate that the prepared CePO 4 and CeO 2 nanoparticles are highly transparent (~ 94%) in the entire UVVis range. The FTIR analysis confirms the presence of phosphate group in the prepared CePO 4 sample. The peaks corresponding to CeO 2 vibrations are seen in the FTIR spectrum of CeO 2 sample. The Photoluminescence (PL) studies of CeO 2 show two emission peaks around 395 nm and 412 nm, corresponding to violet emission, whereas the PL spectra of CePO 4 shows emission peaks at 487 nm and 547 nm corresponding to bluish green and green emissions. TG/DTA results show that in the case of CeO 2 nanoparticles, the samples prepared at a reflux timing of 6 hrs suffer greater weight loss than the samples prepared at a reflux timing of 12 hrs. But the reflux timing doesn&apos;t seem to have any influence on the thermal properties of CePO 4 nanoparticles