Determination of blowout pressures during electron beam welding

During electron beam (EB) welding of developmental units, weld blowouts occurred. It is well documented that the presence of moisture causes the weld blowout. The detrimental effects of water vapor on the weld are experimentally proven [l]. The availability of water vapor in the melt increases the onset and severity of blowout and porosity. Because water vapor is insoluble in the molten metal, it will consequently form either bubbles or boil. On the other hand, hydrogen will react with other impurities present in the melt to form insoluble gas bubbles, which most likely will be entrapped in the fusion zone as porosity. This study attempts to answer the question of what is the critical weld blowout pressure, and to compare the experimental results to the estimated pressure values, so that validated calculations could be extended to other weld configurations

Microstructure and properties of aluminum alloy2090 weldments

ABSTRACT. The effects of welding on aluminum alloy 2090 are examined along with the metallurgical changes associated with welding and aging. The results of the study show that the gas tungsten arc (GTA) and electron beam (EB) weldment properties are controlled by the precipitate size and distribution. There is a tradeoff between strength and elongation. In the as-welded condition, solid solution strengthening is the primary strengthening mechanism present. As a result, the weldment strengths are less than 200 MPa (29 ksi), but the elongations are greater than 4%. In the postweld aged condition, an inhomogeneous distribution of solutes results in an inhomogeneous distribution of precipitates, causing strain localization. Although the weldment strengths increase, the weldment elongations decrease precipitously. The peak strengths of EB and GTA weldments are obtained aging at 160°C (320°F) for 32 h with 75% joint efficiency and at 190°C (374°F) for 16 h with 65% joint efficiency, respectively. Aging at 230 C C (446°F) leads to coarsening of precipitates as well as the intermetallic constituents; the weldment strengths deteriorate rapidly, but the elongations improve. The best overall weldment properties are obtained in the solution heat treated and aged conditions, and are associated with a homogeneous distribution of strengthening precipitates

First mirror test in JET for ITER: Complete overview after three ILW campaigns

The First Mirror Test for ITER has been carried out in JET with mirrors exposed during (1) the third IIW campaign (11.W-3, 2015-2016, 23.33 h plasma) and (ii) all three campaigns, Le LW1 to ILW-3: 20112016 63,52 h in total. All mirrors from main chamber wall show no significant changes of the total reflectivity from the initial value and the diffuse reflectivity does not exceed 3% in the spectral range above 500 nm. The modified Layer on surface has very small amount of impurities such as D, B, C N O and Ni. All mirrors from the divertor (inner, outer, base under the bulk ile) lost reflectivity by 20-80% due to the beryllium-rich deposition also containing D, CN, O, Ni and W. In the inner divertor N reaches 5 x 107 cm2 W is up to 4.3 x 10 cm while the content of Ni is the greatest in the outer divertor 3.8 x 10 cm Oxygen-18 used as the tracer in experiments at the end of ILW-3 has been detected at the level of 1.1 x 10 cm . The thickness of deposited Layer is in the range or 90 nm to 900 nm. The layer growth rate in the base (2.7 pms !) and inner divertor is proportional to the exposure time when a single campaign and all three are compared. In a few cases, on mirrots located at the cassette mouth, flaking of deposits and crosion occurred.EURATOM 63305

Targeting strategies and nanocarriers in vaccines and therapeutics

In the past few decades, remarkable advances have been made in the field of immunology and molecular biology. Even though the efficacy level, protein binding capacity and other pharmacological parameters are extraordinary, formulations have become more challenging in terms of making drugs or antigens reach specific sites of action, the release rate of a drug at the site of action, proper presentation of an antigen by antigen-presenting cells or dendritic cells and other pharmacokinetic and pharmacodynamic parameters of finished drug products and vaccines. The purpose of this review is to present a brief overview of the challenges to drug targeting, especially vaccines, as well as of different approaches designed to overcome these barriers

A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep

Citation: Faburay, B., Wilson, W. C., Gaudreault, N. N., Davis, A. S., Shivanna, V., Bawa, B., . . . Richt, J. A. (2016). A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep. Scientific Reports, 6, 12. doi:10.1038/srep27719Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suitable for use in livestock or humans outside endemic areas. Here we report the evaluation of the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins. In a previous study, the vaccine elicited strong virus neutralizing antibody responses in sheep and was DIVA (differentiating naturally infected from vaccinated animals) compatible. In the current efficacy study, a group of sheep (n=5) was vaccinated subcutaneously with the glycoprotein-based subunit vaccine candidate and then subjected to heterologous challenge with the virulent Kenya-128B-15 RVFV strain. The vaccine elicited high virus neutralizing antibody titers and conferred complete protection in all vaccinated sheep, as evidenced by prevention of viremia, fever and absence of RVFV-associated histopathological lesions. We conclude that the subunit vaccine platform represents a promising strategy for the prevention and control of RVFV infections in susceptible hosts

Evidence of Strong Stabilizing Effects on the Evolution of Boreoeutherian (Mammalia) Dental Proportions

The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar–molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammal

Experimental infection of calves by two genetically-distinct strains of rift valley fever virus

Citation: Wilson, W. C., Davis, A. S., Gaudreault, N. N., Faburay, B., Trujillo, J. D., Shivanna, V., . . . Richt, J. A. (2016). Experimental infection of calves by two genetically-distinct strains of rift valley fever virus. Viruses, 8(5). doi:10.3390/v8050145Additional Authors: McVey, D. S.Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously, we developed a reliable challenge model for sheep that improves the evaluation of existing and novel vaccines in sheep. This sheep model demonstrated differences in the pathogenesis of Rift Valley fever virus (RVFV) infection between two genetically-distinct wild-type strains of the virus, Saudi Arabia 2001 (SA01) and Kenya 2006 (Ken06). Here, we evaluated the pathogenicity of these two RVFV strains in mixed breed beef calves. There was a transient increase in rectal temperatures with both virus strains, but this clinical sign was less consistent than previously reported with sheep. Three of the five Ken06-infected animals had an early-onset viremia, one day post-infection (dpi), with viremia lasting at least three days. The same number of SA01-infected animals developed viremia at 2 dpi, but it only persisted through 3 dpi in one animal. The average virus titer for the SA01-infected calves was 1.6 logs less than for the Ken06-infected calves. Calves, inoculated with either strain, seroconverted by 5 dpi and showed time-dependent increases in their virus-neutralizing antibody titers. Consistent with the results obtained in the previous sheep study, elevated liver enzyme levels, more severe liver pathology and higher virus titers occurred with the Ken06 strain as compared to the SA01 strain. These results demonstrate the establishment of a virulent challenge model for vaccine evaluation in calves. © 2016 by the authors; licensee MDPI, Basel, Switzerland