Procedures for conditioning W- and Ni-moderators for application in positron-scattering measurements

We report recipes for the successful conditioning of tungsten and nickel moderators, for application in positron-scattering experiments. In addition, the comparative performance of those moderators, as a result of these procedures, is assessed.     

Influence of microstructure on the premature failure of a second-intermediate sendzimir mill drive roll

Although a precise understanding of roll failure genesis is complex, the microstructure of a broken roll can often unravel intrinsic deficiencies in material quality responsible for its failure. This is especially relevant in circumstances when, even under a similar mill-operating environment, the failure involves a particular roll or a specific batch of rolls. This paper provides a microstructural insight into the cause of premature breakage of a second-intermediate Sendzimir mill drive roll used at a stainless steel sheet rolling plant under the Steel Authority of India Limited. Microstructural issues influencing roll quality, such as characteristics of carbides, tempered martensite, retained austenite, etc., have been extensively studied through optical and scanning electron microscopy, electron-probe microanalysis, image analysis, and x-ray diffractometry. These are discussed to elucidate specific microstructural inadequacies that accentuated the failure. The study reveals that even though retained austenite content is low (6.29 vol%) and martensite is non-acicular, the roll breakage is a consequence of intergranular cracking caused by improper carbide morphology and distribution.     

Dynamic height anomaly from Argo profiles and sea-level anomaly from satellite altimetry: a comparative study in the Indian Ocean

Altimeter-derived sea-level anomaly (SLA) has been compared with Argo-derived dynamic height anomaly (DHA) in the Indian Ocean. The anomalies have been found to agree quite well in the region above 10°S. The agreement is improved when climatological salinity is replaced by Argo salinity. Seasonal variation of correlation of DHA computed with Argo salinity and SLA has also been studied. The reasons for the poor correlation could be attributed to the fact that there is a barotropic (non-steric) component of the SLA, not captured by DHA, which is a purely steric effect. It has been also found that the impact of halosteric component on dynamic height is quite high in certain regions of the Arabian Sea because of (i) low-salinity water of southern region advected into the region by Somali and North Equatorial Current, (ii) upwelled water of low salinity during south-west monsoon along the Arabian coast and (iii) precipitation and river run-off from rivers in the eastern Arabian sea contributing to the local formation of low-salinity water. In the Bay of Bengal, the factors responsible for the large impact of halosteric component are precipitation and river influx in the northern part. In the south-eastern Indian Ocean, Indonesian Throughflow is the governing factor for this impact.     

Prediction of Flow Stress in Cadmium Using Constitutive Equation and Artificial Neural Network Approach

A model is developed to predict the constitutive flow behavior of cadmium during compression test using artificial neural network (ANN). The inputs of the neural network are strain, strain rate, and temperature, whereas flow stress is the output. Experimental data obtained from compression tests in the temperature range ?30 to 70 °C, strain range 0.1 to 0.6, and strain rate range 10^?3 to 1 s^?1 are employed to develop the model. A three-layer feed-forward ANN is trained with Levenberg-Marquardt training algorithm. It has been shown that the developed ANN model can efficiently and accurately predict the deformation behavior of cadmium. This trained network could predict the flow stress better than a constitutive equation of the type $ \dot{\upvarepsilon } = A\sinh (\upalpha /\upsigma )^{n} \exp ( - Q/RT) $ .     

External Refining of Molten Cast Iron

Abstract

The feasibility of removing manganese and phosphorus from molten iron by treatment with polyvinyl chloride and straight hydrocarbons (paraffin wax/polythene) respectively has been examined. Simultaneous dephosphorisation and desulphurisation of cast iron melts has been tried by combined addition of polythene granules and sodium carbonate. Appreciable refining of cast iron melts occured in each of these experiments.     

Universal Properties and Specificities of the β2-Adrenergic Receptor-Gs Protein Complex Activation Mechanism Revealed by All-Atom Molecular Dynamics Simulations

G protein-coupled receptors (GPCRs) are transmembrane proteins of high pharmacological relevance. It has been proposed that their activity is linked to structurally distinct, dynamically interconverting functional states and the process of activation relies on an interconnecting network of conformational switches in the transmembrane domain. However, it is yet to be uncovered how ligands with different extents of functional effect exert their actions. According to our recent hypothesis, based on indirect observations and the literature data, the transmission of the external stimulus to the intracellular surface is accompanied by the shift of macroscopic polarization in the transmembrane domain, furnished by concerted movements of highly conserved polar motifs and the rearrangement of polar species. In this follow-up study, we have examined the β₂-adrenergic receptor (β₂AR) to see if our hypothesis drawn from an extensive study of the μ-opioid receptor (MOP) is fundamental and directly transferable to other class A GPCRs. We have found that there are some general similarities between the two receptors, in agreement with previous studies, and there are some receptor-specific differences that could be associated with different signaling pathways.     

Effect of compositional variation and fineness on the densification of MgO–Al2O3 compacts

Single stage densification of magnesia—alumina compacts were studied with MgO to Al₂O₃ molar ratios 1:1 (stoichiometric spinel), 2:1 (magnesia rich spinel) and 1:2 (alumina rich spinel). Attritor milling has been adopted to produce variation in fineness. Milling greatly improved the densification. Densification was found to be easier for the magnesia rich composition and difficult for the alumina rich one. X-ray diffraction patterns showed the expected phases in stoichiometric and magnesia rich spinel. Alumina rich composition showed no free corundum phase on sintering at 1650°C and only spinel phase marks the complete solid solution of excess alumina in spinel at this composition. EDAX analysis also supports the event and also reflects that the impurities are mainly present at the grain boundaries.     

Effect of Preaging Deformation on Aging Characteristics of 2507 Super Duplex Stainless Steel

In the present study, precipitation of sigma (σ) phase was investigated over the temperature range of 700-850 °C in undeformed and deformed (60% cold rolling) samples of 2507 super duplex stainless steel. The fraction of sigma phase formed as a result of the transformation α → σ + γ₂ increases with increasing time and temperature. The increase in sigma phase leads to increase in yield strength and decrease in ductility. Preaging deformation leads to accelerated precipitation of sigma phase. The activation energy for sigma phase precipitation in deformed sample is found to be lower than that in undeformed sample.     

Fatigue Failure of Rubber-to-Rubber Joints

This paper presents an experimental investigation on fatigue failure of rubber-to-rubber similar and dissimilar joints made from natural rubber and EPDM. The effects of interlinking density, relative proportion of one matrix in the two-component joints, filler loading in the filled part of the joint and strain level on the fatigue life have been studied. Adhesion (peel strength) between similar and dissimilar rubber-to-rubber joints has also been investigated to attempt to determine a correlation between adhesion and fatigue failure.     

Clinical Advances in Molecular Biomarkers for Cancer Diagnosis and Therapy

Cancer diagnosis is currently undergoing a paradigm shift with the incorporation of molecular biomarkers as part of routine diagnostic panel. The molecular alteration ranges from those involving the DNA, RNA, microRNAs (miRNAs) and proteins. The miRNAs are recently discovered small non-coding endogenous single-stranded RNAs that critically regulates the development, invasion and metastasis of cancers. They are altered in cancers and have the potential to serve as diagnostic markers for cancer. Moreover, deregulating their activity offers novel cancer therapeutic approaches. The availability of high throughput techniques for the identification of altered cellular molecules allowed their use in cancer diagnosis. Their application to a variety of body specimens from blood to tissues has been helpful for appreciating their use in the clinical context. The development of innovative antibodies for immunohistochemical detection of proteins also assists in diagnosis and risk stratification. Overall, the novel cancer diagnostic tools have extended their application as prognostic risk factors and can be used as targets for personalized medicine.