Low Cost In-Situ Formation of AIN - B- SiC

AIN-a-SiC composite powders have been prepared by in-situ high temperature reaction process. By appropriate mixing of Charred Rice Husk (CRH) and aluminium powder, samples containing 30-70% A1N (balance SiC) have been produced. Nitridation has been done by high purity N, gas at temperatures ranging from 1400-17000C.Amorphous SiO, and carbon present in CRH have been utilized for the formation of [i-SiC. At about 1550°C the reaction products are only [3-SiC and AIN, whereas,below 1550°C other phases, like a-A1,03, Al, Si are the reaction products. It has also been observed that above 1600°C SiC starts going into the solid solution of A1N. The final products have been identified and characterized by XRD, SEM and EDX analysis

Genetic and phenotypic parameters of growth traits in Muzaffarnagari sheep

Data on 2,540 Muzaffarnagari lambs born during 1992– 2006 at CIRG were recorded to study growth traits and genetic and phenotypic parameters. Sex and period of lambing had highly significant influence on all the body weights and average daily weight gains except significant effect on 6-and-9-month body weights. Season of birth showed significant influence on 6-and-9-month weight and on all ADGs except ADG during 0–3 month age group. Male lambs gained higher weight than female lambs at all the growth stages while year of lambing did not show any definite trend. Dams’ weight at lambing showed highly significant influence on birth and 3-month-body weight. Maximum growth of lambs (around 44%) was recorded during 0–3 month (pre-weaning) age followed by 3–6, 9– 12 and 6–9 age groups. This period of growth may be considered very crucial and should be ensured with proper management, feeding and health care for better productivity. Moderate to high genetic correlations of birth weight with subsequent weights indicated that selection of animals at early age will bring genetic improvement at later growth stages

Microsatellite-based phylogeny of Indian domestic goats

<p>Abstract</p> <p>Background</p> <p>The domestic goat is one of the important livestock species of India. In the present study we assess genetic diversity of Indian goats using 17 microsatellite markers. Breeds were sampled from their natural habitat, covering different agroclimatic zones.</p> <p>Results</p> <p>The mean number of alleles per locus (NA) ranged from 8.1 in Barbari to 9.7 in Jakhrana goats. The mean expected heterozygosity (He) ranged from 0.739 in Barbari to 0.783 in Jakhrana goats. Deviations from Hardy-Weinberg Equilibrium (HWE) were statistically significant (P < 0.05) for 5 loci breed combinations. The D_Ameasure of genetic distance between pairs of breeds indicated that the lowest distance was between Marwari and Sirohi (0.135). The highest distance was between Pashmina and Black Bengal. An analysis of molecular variance indicated that 6.59% of variance exists among the Indian goat breeds. Both a phylogenetic tree and Principal Component Analysis showed the distribution of breeds in two major clusters with respect to their geographic distribution.</p> <p>Conclusion</p> <p>Our study concludes that Indian goat populations can be classified into distinct genetic groups or breeds based on the microsatellites as well as mtDNA information.</p

Phylogeography and origin of Indian domestic goats

The Indian subcontinent contains 20 well-characterized goat breeds, which vary in their genetic potential for the production of milk, meat, and fibre; disease resistance; heat tolerance; and fecundity. Indian goats make up 20% of the world's goat population, but there has been no extensive study of these economically important animals. Therefore, we have undertaken the present investigation of 363 goats belonging to 10 different breeds from different geographic regions of India using mtDNA sequence data from the HVRI region. We find evidence for population structure and novel lineages in Indian goats and cannot reconcile the genetic diversity found within the major lineage with domestication starting 10,000 years ago from a single mtDNA ancestor. Thus, we propose a more complex origin for domestic goats

Investigation of direct and maternal genetic effects on days open in Jersey crossbred cattle

Estimates of (co)variance and genetic parameters for days open (DO) of Jersey crossbred cattle were estimated by restricted maximum likelihood (REML), fitting 6 animal models, including various combinations of maternal effects. Data on 792 records of 223 Jersey crossbred animals, descended from 51 sires and 170 dams were used. The direct heritability estimates for days open ranged from 0.04 to 0.10 depending on the model applied. The additive maternal effects varied from 0.06 to 0.09 in different models in this study, whereas the estimates of the fraction of variance due to maternal permanent environmental effects were practically negligible to very low (0– 4% of the phenotypic variance), irrespective of the models used. Results suggested that direct and maternal additive effects were important for this trait but, the low heritability estimates indicated little scope of genetic progress through selection for this trait

First Record of Occurrence of Albino Crestless Himalayan Porcupine Hystrix Brachyura Linnaeus, 1758 (Rodentia: Hystricidae) in India

Volume: 97Start Page: 274End Page: 27

Correlation between the mechanical properties and the microstructural behaviour of Al2O3–(Ag–Cu–Ti) brazed joints

A micro-indentation technique was used to determine the strength of Al2O3–(Ag–Cu–Ti) brazed joints. Different Ag–Cu–Ti alloy compositions were used for brazing Al2O3 at temperatures of 800, 900, 1000, 1100 and 1200 °C under vacuum with a constant load. EPMA, SEM–EDX and XRD analyses of the brazed samples reveal that adjacent to the Al2O3, the amount of diffused Ti is much higher than Cu and the reaction layer is identified as TiO, whereas, between TiO and the filler metal, the phase Ti3Cu3O was confirmed. An attempt was made to correlate the bond strength and the microstructure of the brazed samples. It has been observed that higher amounts of Ag present in the filler metal increases the activity of Ti, which improves the bond strength. The filler metals having higher amounts of Cu form different Cu–Ti intermetallics, but these intermetallics do not directly react with the ceramics. The alloys 97(Ag28Cu)3Ti and 97(Ag40Cu)3Ti exhibited good performance to join Al2O3 ceramics

Characterization of the brazed joint interface between Al2O3 and (Ag-Cu-Ti)

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Characterization of interface of Al2O3–304 stainless steel braze joint

Sintered Al2O3 is brazed with 304 stainless steel (SS) using 97(Ag28Cu)3Ti active filler alloy at 900 and 1000 °C. The interfaces developed during brazing have been systematically characterized and the results show that the thickness of the interfaces is 15–20 μm and 10–15 μm on SS side and Al2O3 side respectively. The presence of TiO, Cu3Ti3O and FeTi phases at the Al2O3 interface and FeTi, and Fe35Cr13Ni3Ti7 phases at the SS interface have been confirmed through XRD and TEM studies. Microhardness analysis across the brazed interfaces suggest that the SS interface (300–600 Hv) is harder than that of the SS substrate (200–250 Hv) whereas alumina interface (550–900 Hv) is softer than that of the alumina substrate ( 1900 Hv). It is concluded that the various new phases that are formed during brazing are responsible for the variation in the hardness values

Effect of Ti diffusivity on the formation of phases in the interface of alumina-alumina brazed with 97(Ag40Cu)3Ti filler alloy

Sintered alumina was brazed with 97(Ag40Cu)3Ti active filler alloy at 1073, 1173, 1273, 1373 and 1473 K. The elemental concentrations along with the thickness of the brazed interface have been measured by the quantitative EPMA line profile analysis. Diffusivity of the elements across the brazed interface is determined using Matano-Boltzmann equation. The diffusivity of Ti, Al, Cu and Ag at different temperature helps in optimizing the brazing process parameter as well as the nature of reaction products formed in the brazed interface. XRD and TEM-EDX analyses confirm the reaction products, such as TiO, Cu3Ti3O. Presence of these phases control the coefficient of thermal expansion mismatches between the substrates and the active filler alloy at the brazed interface. Feasibility of the formation of the phases at the interface has further been verified thermodynamically