Biosecurity of Poultry Worker Related to Avian Influenza in Bangladesh

Research on biosecurity of poultry workers of Live Bird Market (LBM) in urban and rural areas related to highly pathogenic avian influenza (AI) was undertaken during March-June, 2014 at Keshabpur upazila (22°48´-22°57´N latitude and 89°06´-89°22´E longitude), Jessore, Bangladesh. A non-randomized (purposive) sampling method was applied and a descriptive type of cross sectional study was performed among 72 workers, dividing them into two groups as 36 urban and 36 rural poultry workers of LBM through split-halves variation technique. They were interviewed confidentially in their work place using a structured pretested questionnaire. Among respondents 53%, 75%, 45%, 81%, and 56% of urban and 50%, 42%, 50%, 89%, and 36% of rural residence had attended up to primary school, knowledge about AI through media like TV and radio, used proper personal protective equipment as mask and gloves, washed their hands and equipment after finishing work and cleaned stalls/cages daily and mostly they used water as a cleaning material, respectively. In urban (14%) and rural (36%) workers used the same vehicle to transport poultry and humans. A combined effort is required to enhance knowledge and change behavior among those most at risk in low-income countries and precautions necessary to avoid spreading the virus among poultry and humans

Fatigue crack growth retardation in an HSLA steel in benign environments

The crack growth and closure were examined for fatigue loading of an HSLA steel in non-corroding media. R and ΔK dependent significant crack growth retardation was observed in NaOH. Presence of a passive film at high R and self repair of the film and formation of an additional oxide layer at low R could explain the retardation

Genotype-Phenotype Study of the Middle Gangetic Plain in India Shows Association of rs2470102 with Skin Pigmentation

Our understanding of the genetics of skin pigmentation has been largely skewed towards populations of European ancestry, imparting less attention to South Asian populations, who behold huge pigmentation diversity. Here, we investigate skin pigmentation variation in a cohort of 1,167 individuals in the Middle Gangetic Plain of the Indian subcontinent. Our data confirm the association of rs1426654 with skin pigmentation among South Asians, consistent with previous studies, and also show association for rs2470102 single nucleotide polymorphism. Our haplotype analyses further help us delineate the haplotype distribution across social categories and skin color. Taken together, our findings suggest that the social structure defined by the caste system in India has a profound influence on the skin pigmentation patterns of the subcontinent. In particular, social category and associated single nucleotide polymorphisms explain about 32% and 6.4%, respectively, of the total phenotypic variance. Phylogeography of the associated single nucleotide polymorphisms studied across 52 diverse populations of the Indian subcontinent shows wide presence of the derived alleles, although their frequencies vary across populations. Our results show that both polymorphisms (rs1426654 and rs2470102) play an important role in the skin pigmentation diversity of South Asians

Fatigued and fractured regions in a silicon-carbide whisker-reinforced alumina composite

Fatigue cracked and fast fractured regions in four point bend specimens prepared from 25 wt% silicon carbide whisker reinforced alumina composites were examined by Scanning Electron Microscopy. In the fatigue cracked region, the alumina matrix failed mainly in a transgranular mode and the whiskers failed mainly with a flat fracture surface but without pullout. On the other hand, in the fast fractured region, the whiskers failed predominantly by pullout and the alumina matrix failed in a mixed mode with about half in transgranular and the other half in intergranular fracture. Thus, to improve the fracture toughness of the material, the grain boundary strength of alumina and the matrix whisker interfacial bonding should be improved. To increase the resistance to fatigue, the fracture strength of the alumina grains should be improved by using finer alpha-alumina particles and the fatigue strength of the whisker has to be increased by improving the uniformity in distribution of beta-SiC whiskers during hot pressing

Fractography of fatigued and fractured regions in a silicon carbide whisker reinforced alumina composite

Fatigue cracked and fast fractured regions in four point bend specimens prepared from 25 wt% silicon carbide whisker reinforced alumina composites were examined by Scanning Electron Microscopy. In the fatigue cracked region, the alumina matrix failed mainly in a transgranular mode and the whiskers failed mainly with a flat fracture surface but without pullout. On the other hand, in the fast fractured region, the whiskers failed predominantly by pullout and the alumina matrix failed in a mixed mode with about half in transgranular and the other half in intergranular fracture. Thus, to improve the fracture toughness of the material, the grain boundary strength of alumina and the matrix whisker interfacial bonding should be improved. To increase the resistance to fatigue, the fracture strength of the alumina grains should be improved by using finer α-alumina particles and the fatigue strength of the whisker has to be increased by improving the uniformity in distribution of β-SiC whiskers during hot pressing

Effect of magnetizing field on the martensitic transformations in a melt spun NiMnGa alloy

The investigation addresses the effect of magnetizing field on the magnetic properties of melt spun Ni52.84Mn19.6Ga27.56 (at%) alloy ribbons. Magnetization behaviour at different fields was observed using a superconducting quantum interference device magnetometer for heating and cooling cycles. The plots showed distinct changes in magnetization around the characteristic temperatures at austenitic start and finish (A(S), A(F)), martensitic start and finish (M-S, M-F). With increasing field A(S), M-F were unaffected. In the range of martensitic start and its finish temperature, the zero field cooled and field cooled measurements indicated magnetization drops indicating antiferromagnetic interactions, which is characteristic of the martensitic phase formation. It was shown from x-ray diffraction analysis that the low martensitic fraction in the majority austenite phase induced the splitting in the L2(1) austenitic ordering. This was further corroborated by the evidence of a few martensitic plates around grain boundaries at room temperature which is close to martensitic start temperatur

Fatigue and creep damage and its correlation with microstructure of a service exposed first stage turbine blade in a power plant

This paper deals with assessment of high temperature load controlled fatigue and creep properties of as received and 31,325 engine operating hours service exposed first row gas turbine blade in a power plant. High temperature fatigue and accelerated creep properties were evaluated from various regions, namely root portion (bottom portion), middle region or the airfoil region and the top region of the blade. The root portion showed superior fatigue and creep properties compared to the aerofoil region of the blade where the temperature distribution is maximum and the top or tip region which is considerably narrow and brittle. The microstructural assessment of as received service exposed gas turbine blade of first row of gas turbine have been interpreted, which is required for developing process & technology for rejuvenation of turbine blades. The mechanical properties of each region were correlated with its corresponding microstructural characteristics. The blade is made of nickel base superalloy Udimet-520. Significant coarsening of γ' precipitates in hot zones, e.g., root and mid sections, as compared to the base microstructure of below platform region was observed. The coarsening occurred in the aerofoil region and was maximum in the top region of the blade. The original thin and nearly continuous distribution of grain boundary carbide precipitates became discontinuous with little increase in size in the root section whereas it changed to thick continuous precipitation enveloped by γ' phase in mid section. Grain boundary cavitations are not observed. Therefore, Hipping is not essential for rejuvenation. In addition, the usual distribution of intragranular MC carbide precipitates in below platform section is nearly dissolved in mid section while smaller size is observed in bottom or root section. But the blocky MC precipitates at grain boundaries or close to grain boundaries are degenerated into needle shaped sigma phase in the mid and top sections. Formation of intragranular Cr-rich sigma phase is also observed in root, airfoil and top sections but their frequency of occurrence is more in mid&top sections than the root section. The appearance of sigma phase also signals for the rejuvenation. All the grain boundaries in mid section and top section show enveloping of M23C6 grain boundary precipitates with γ' phase, because of following transformation at grain boundaries: MC + γ ⇒ M23C6 + γ′(γ′ envelopes the M23C6). The remnant coating at root section is 100–120 mm. In mid section it is about 10 μm with base metal attack down to 20 μm. In addition, the width of TCP phase formation zone in subsurface region of base metal is about 200 m in mid section while it is about 100 μm in root section

Failure Analysis of LP Turbine Blade of NTPC-Tanda

A 110 MW turbine suffered damage to 4A-stage blade prematurely. The failed blade along with a virgin blade(for comparison purpose) were recieved at NML for various metallurgical tests to find out the cause of failure. SEM fractography studies of the failed blade indicated the characteristic features of fatigue along withlarge amounts of corrosion products. Further, SEM (with EDAX) studies of the surface (pertaining to the pressure side) of the failed blade revealed the presence of globules caused by chloride attack. In addition, analysis of failed blade surface by Raman Spectroscopy also revealed the presence of chlorides and oxygen. The microstructure, chemical composition and mechanical properties (tensile and hardness of the material used for the failed blade were found to be alright as per the standards thus indicating the failed blade material was healthy. Based on the above findings, it is concluded that the failure took place as a result of chloride attack. It was recommended that the sources of the chlorides be eliminated and that the rema-ining blades be inspected at regular maintenance intervals for evidence of cracking