Segregation of B, P, and C in the Ni-Based Superalloy, Inconel 718

Small additions of B, P, and C can result in dramatic changes in the mechanical performance and welding behavior of Inconel 718. Although additions of B and P improve the mechanical properties, they have a detrimental effect on weldability. Adding C mitigates the negative effect on welding while retaining the improvements in mechanical performance. In this study, precise observations of the segregation of B, P, and C to the grain boundaries are made using site-specific atom probe tomography and NanoSIMS. Changes in the segregation behavior provide a quantitative explanation for the welding response, where hot cracking is attributed to the formation of a eutectic film. Calculations of the relative positions of the B, P, and C revealed that these atoms were less likely to cluster together in the presence of C, providing insight into the likely mechanisms behind the segregation behavior in this complex, multicomponent alloy.     

Assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya

A radiation dose assessment exercise was carried out for the edible biota Solanum nigrum, Carica papaya, Raphnus sativum and Phaseolus domesticus due to naturally available radionuclides (40)K, (238)U and (232)Th in the Domiasiat area in Meghalaya, India. The concentration of radionuclides in biota and corresponding soil was measured by the NaI(Tl) detector having a minimum detection limit (efficiency, 32.4%) and machine counting time of 3000 s. The obtained transfer factor for (40)K was 0.3061, 0.7163, 0.1988 and 0.1279, for (232)Th 0.0003, 2.22E-05, 2.71E-05 and 3.45E-05 and for (238)U 1.46E-05, 9.73E-05, 1.46E-05 and 3.11E-05 (ratio) in each biota, respectively. The detailed physiological and morphological study of the biota was carried out. The point source dose distribution (source?target) hypothesis was applied for the radiation absorbed fraction. The generated data were modelled using FASSET and obtained un-weighted total dose was 1.78E-04, 6.84E-03, 8.46E-03 and 1.73E-04 μGy h(-1), respectively, finally compared with the IAEA and UNSCEAR data set for screening level dose risk assessment.     

Environment-Friendly Synergistic Abiotic Stress for Enhancing the Yield of Lipids from Oleaginous Yeasts

The microbial lipids isolated from oleaginous yeasts are a potential alternative to tree borne oils. There is a need to optimize and enhance the production of lipid by various stress approaches. In the present study, yeasts are subjected to physico-chemical stresses, and growth, as well as lipid concentration at different time intervals are monitored. It is found that the nanoparticles (NP) such as Ag-NP and Zn-NP have an inhibitory effect on yeast growth. Most yeast strains show an increase in growth and lipid accumulation when ionic liquid (1-ethyl-3-methylimidazolium acetate) ([EMIM][OAc]) and table salt (NaCl) stress are applied. Lipid is chemically characterized using gas chromatography furnished with flame ionization detector (GC-FID), GC/MS, and NMR techniques. It contains a higher percentage of saturated fatty acids (SFA: 74.3%), monounsaturated fatty acids (19.1%) with low amounts of polyunsaturated fatty acids (1.9%). The thermo-stability study reveals that the lipid have higher volatility (380–410 °C) as closely compared with coconut oil, and much lower with respect to the winged bean oil (430–470 °C). The melting point of the lipids (37 °C) is determined through differential scanning calorimetry (DSC). The DSC and physico-chemical properties are supported that the yeast lipids may use as a cocoa-butter substitute. Production of lipid under NaCl stress (200 × 10⁻³ m ) is more than 60.4% higher as compared to the control. However, the combined stress effect of NaCl (200 × 10⁻³ m ) and 15 × 10⁻³ m of [EMIM][OAc] results in more than 96.4% yield of lipid. The exchange of inorganic and organic ions in combined treatment forces the microbial cells to accumulate more amounts of lipid, which may form a lipid-emulsion layer to protect the cell from osmosis. It is interestingly observed that the stress cells shift the flux to accumulate a significantly improved percentage of SFA, which could be provided better protection cover due to its expanded structure, less reactive characteristics, and completely insoluble nature in ionic-aqueous solvent. Practical applications: Oleaginous yeast is multiplied in a very limited space, and easily scalable for sustainable production of lipid to meet its commercial demand. This novel approach for enhancing the yield of lipid with the application of synergistic stress in between NaCl and the green solvent (ionic liquid) is being reported for the first time. This lipid has potential alternative applications as cocoa-butter.     

Effect of Grain Size on the Weldability of Cast Alloy 718

Electron beam welding was conducted on cast alloy 718 with varying grain sizes obtained using Microcast (MX™) and conventional cast (CC) techniques. The average value per section of Total Crack Length (Av. TCL) was measured on each cross section and used to represent the material's weldability. It was found for the first time that the grain size had a reduced effect on the weldability of cast alloys, relative to that reported in the literature for wrought alloys; i.e., increased grain size in the range of 90-3000 microns resulted in improved weldability. This was determined to be related to the probability of welds intersecting grain boundaries and causing grain boundary microfissuring. The conclusion from the experimental analysis is corroborated by the use of a Weibull-type analysis to evaluate the probability of a weld microfissure occurring relative to the grain size. As grain size increases, the probability of the weld intersecting the grains is reduced, and thus, the likelihood of microfissuring is reduced. With regard to a single crystal, there are no grain boundaries intercepting the weld (probability = 0), and thus, microfissuring related to constitutional liquation of primary carbides, or segregation of species to grain boundaries would not occur.     

Human Prostatic Acid Phosphatase: Structure,Function and Regulation

Human prostatic acid phosphatase (PAcP) is a 100 kDa glycoprotein composed of two subunits. Recent advances demonstrate that cellular PAcP (cPAcP) functions as a protein tyrosine phosphatase by dephosphorylating ErbB-2/Neu/HER-2 at the phosphotyrosine residues in prostate cancer (PCa) cells, which results in reduced tumorigenicity. Further, the interaction of cPAcP and ErbB-2 regulates androgen sensitivity of PCa cells. Knockdown of cPAcP expression allows androgen-sensitive PCa cells to develop the castration-resistant phenotype, where cells proliferate under an androgen-reduced condition. Thus, cPAcP has a significant influence on PCa cell growth. Interestingly, promoter analysis suggests that PAcP expression can be regulated by NF-κB, via a novel binding sequence in an androgen-independent manner. Further understanding of PAcP function and regulation of expression will have a significant impact on understanding PCa progression and therapy.     

Thermal plasma spheroidization of aluminum oxide and characterization of the spheroidized alumina powder

Spheroidization of aluminum oxide powder was done by thermal plasma processing. The powder was injected into the plasma jet issuing out of a DC plasma torch. Trajectories of the particles in the plasma jet were seen using a high speed camera and then in-flight velocity and temperature of alumina particles were determined using a ‘Spray Watch’ system. Characterization of the spheroidized powder was done by Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The results showed that increase of the plasma torch power leads to increase in the extent of spheroidization and conversion to γ-alumina. Results obtained showed that the process can be extended to synthesize free flowing alumina powder for thermal spray applications.     

Bayesian Unit Root Test in Nonnormal AR(1) Model

In this paper, we approximate the distribution of disturbances by the Edgeworth series distribution and propose a Bayesian analysis in a nonnormal AR(1) model. We derive the posterior distribution of the autocorrelation and the posterior odds ratio for unit roots hypothesis in the AR(1) model when the first four cumulants of the Edgeworth series distribution are finite and the higher order cumulants are negligible. We also apply the posterior analysis to eight real exchange rates and investigate whether these exchange rates behave like a random walk or not.     

The role of renewables in meeting rural energy needs in South Asia

South Asia is the poorest and most deprived region in the world. Rural population represent upto 75% of its population. Traditionally the rural masses have been dependent on fuelwood and agro-residues - both due to poverty and due to lack of local fossil resources. South Asia is expected to continue its dependence on renewable sources of energy for meeting rural energy needs to the year 2010. New renewables are expected to enter rural markets as technology develops.     

Transient Analysis of Creeping Wave Modes Using 3-D FDTD Simulation and SVD Method

Creeping wave modes on smooth structures are of importance in the control of scattering properties, such as radar cross section of such structures. We have shown a novel procedure to examine the excitation of creeping wave modes by plane wave illumination of a perfectly electrically conducting (PEC) cylinder. Detailed information about transients of creeping wave modes and their spatial structure, have been obtained for the first time using Singular Value decomposition (SVD) analysis of 3D Finite Difference Time Domain (FDTD) data. The transient analysis shows how the amplitudes of different modes vary in time, and how the dominant modes eventually stabilize to the time-harmonic solution given by analytical methods. Although the method is computationally expensive, this technique will be particularly useful for purely transient signals, complex geometries and situations involving spatially-varying material properties such as a plasma shielded object.     

All Slot-Die Coated Non-Fullerene Organic Solar Cells with PCE 11%

Slot-die (SD) coating is used to fabricate fully solution processed organic solar cells (OSCs) based on a blend of high performance donor polymer (PTB7-Th) and a non-fullerene acceptor (IEICO-4F) for stable devices over extended periods of operation. The optimization of a sequential deposition process of transport and active layers, under ambient conditions, enable high efficiency slot-die coated solar cells with remarkable power conversion efficiencies (PCE) > 11.0% to bridge the gap between lab-to-fab. Fully slot-die coated inverted OSCs are demonstrated with efficiencies reaching 11% along with 1 cm² devices, proving the scalability and reproducibility of the proposed technique. Further, replacing the evaporated Ag electrode with solution processed Ag nanowire (AgNW) electrodes shows the highest light utilization efficiency of 5.26% for semi-transparent OSC with a PCE of 9.07% and average visible transmission of 58%.