Powder bed fusion additive layer manufacturing of titanium alloys

Powder bed fusion (PBF) techniques for additive layer manufacturing (ALM) are reviewed with a focus on titanium alloys production. Selective laser melting and electron beam melting are discussed in terms of feedstock production and processing-microstructure relationships. To control the PBF processes, an outline is presented on the computational modelling approaches for simulating process parameters and defects such as residual stresses and porosity at different length scales. It is concluded that by improving powder production techniques, designing new alloys and further developing ALM hardware, PBF techniques can reach commercial maturity. This review was submitted as part of the 2019 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged

Electronic and optical properties of 5-AVA-functionalized BN nanoclusters: A DFT study

We carried out detailed density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations upon 5-aminolevulinic acid-functionalized B12N12 and B16N16 nanoclusters with the B3LYP, B3PW91, and PBE methods using the 6-311+G∗∗ basis set. The calculated adsorption energies of 5-aminolevulinic acid with the BN nanoclusters were evaluated at T = 298.15 and 311.15 K in the gaseous and aqueous environments with the B3LYP, B3PW91, and PBE methods. Our results showed that the adsorption of the 5-AVA molecule (NH2 group) with B12N12 is more favorable than-with the B16N16 nanocluster in the gas and solvent phases. It is anticipated that a 5-aminolevulinic acid (5-AVA) drug incorporating BN clusters could find application in drug delivery systems and in biomedical devices. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016

AFM Investigation of Epoxy Fracture Surfaces Indicating Nanoplasticity

Noble metal nanoparticles have a great potential for biological study, especially the use of gold nanoparticles is very popular. In this work gold nanoparticles (GNPs), silver nanoparticles (SNPs) and goldsilver hybrid nanoparticles (HNPs) synthesized and used as a carrier for electrochemical investigation of redox protein. Optical characterization of these nanoparticles was performed by UV-Vis spectroscopy. The maximum of the plasmon band for GNPs, SNPs and HNPs (ratio of 1:1) are 524, 392 and 455 nm respectively. The optical absorption spectra of HNPs solution shows only one plasmon absorption, it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. LCR meter study shows the HNPs is best conductance in compare of GNPs and SNPs. Therefore, the electron transfer of the homogenous GOx, HRP and Hb was investigates by electrochemical method in presence of HNPs. They demonstrated quasi-reversible cyclic voltammograms with a formal potential of -479, -178 and -168 mV in 50 mM phosphate buffer solution at pH 7.4 respectively

AFM Investigation of Epoxy Fracture Surfaces Indicating Nanoplasticity

Noble metal nanoparticles have a great potential for biological study, especially the use of gold nanoparticles is very popular. In this work gold nanoparticles (GNPs), silver nanoparticles (SNPs) and goldsilver hybrid nanoparticles (HNPs) synthesized and used as a carrier for electrochemical investigation of redox protein. Optical characterization of these nanoparticles was performed by UV-Vis spectroscopy. The maximum of the plasmon band for GNPs, SNPs and HNPs (ratio of 1:1) are 524, 392 and 455 nm respectively. The optical absorption spectra of HNPs solution shows only one plasmon absorption, it is concluded that mixing of gold and silver leads to a homogeneous formation of alloy nanoparticles. LCR meter study shows the HNPs is best conductance in compare of GNPs and SNPs. Therefore, the electron transfer of the homogenous GOx, HRP and Hb was investigates by electrochemical method in presence of HNPs. They demonstrated quasi-reversible cyclic voltammograms with a formal potential of -479, -178 and -168 mV in 50 mM phosphate buffer solution at pH 7.4 respectively

Intramedullary spinal melanocytoma

Meningeal melanocytoma is a benign lesion arising from leptomeningeal melanocytes that at times can mimic its malignant counterpart, melanoma. Lesions of the spine usually occur in extramedullary locations and present with spinal cord compression symptoms. Because most reported spinal cases occur in the thoracic region, these symptoms usually include lower extremity weakness or numbness. The authors present a case of primary intramedullary spinal meningeal melanocytoma presenting with bilateral lower extremity symptoms in which the patient had no known supratentorial primary lesions. Gross total surgical resection allowed for full recovery, but early recurrence of tumor was detected on close follow-up monitoring, allowing for elective local radiation without loss of neurological function. Case reports of such tumors discuss different treatment strategies, but just as important is the close follow-up monitoring in these patients even after gross total surgical resection, since these tumors can recur

A Novel Nanowire Metal Converter for Improvement the Efficiency of the Gas-filled Radiation Detectors

Metal nanowires, due to their special physical properties and also high surface to volume ratio, can have considerable applications in designing and development of novel nano devices. For the radiation shielding, higher absorption coefficient of nano structures in comparison to bulk ones is an advantage. In gas detectors, designing a proper converter with higher efficiency which absorbs higher energy of gamma and X-rays and convert it to free electrons is one of the major requirements. Since the nano wires have higher surface to volume ratio in comparison to the bulk ones, so it is expected that with the same thickness, the generated electrons have higher chance to escape from the surface. In this work, the random Copper nanowires with diameter of 40 nm are deposited on very thin glass slide. This nano structure with thickness of 30 μm is tested with X-rays energy between 12 to 22 keV. The results clearly show that this nano structure for the energy of 20 keV can release electrons three times more than the bulk ones. This novel nanoconverter with higher quantum efficiency can have many applications in high energy physics, medical imaging, and astronomy

Bank Failure prediction: corporate governance and financial indicators

Most failure prediction studies have relied on using financial ratios as predictors. The most suitable financial predictors for banks are financial ratios following the CAMEL rating system. Also, corporate governance has been proven to be an important aspect of banks, especially after the financial crisis. Given its importance, we test the ability of corporate governance to enhance the prediction of bank failure. While there are only few studies that examine efficiency of corporate governance as a failure predictor, there are scarcely any studies that examine it as predictor of US banks failure. Using discriminant analysis, we predict the failure of banks insured by the Federal Deposit Insurance Corporation during the period from 2010 to 2018 using financial and non-financial predictors. We find that combining CAMEL ratios with corporate governance variables not only enhances the accuracy of prediction but also extends the time horizon of prediction to three years before failure. We also show that the earnings of banks are more significant in predicting bank failure than the capital structure and asset quality. The results further reveal that the CEO compensation, voting rights and institutional ownership are more significant predictors than the board characteristics. These results are robust when using logit regression. This paper provides insight to banks, regulators and shareholders by showing that corporate governance and banks earnings are strong predictors of bank failure

Chemical, microbial and sensory changes of silver carp (Hypophthalmichthys molitrix) fish treated with black cumin (Nigella sativa L.) extract during storage at refrigerator

The changes in chemical, microbial and quality sensory of fillets for silver carp fish treated with black cumin extract during refrigerated storage were investigated. The fish were divided into two groups. First group was dipped in black cumin extract with concentration of 1% and received the highest score in sensory evaluation. Then the fishes were wrapped in polyethylene package. The second group, as the control samples, were wrapped in polyethylene package after dipping in distilled water. All treatments were stored at refrigerator temperature (1±4°C). The microbial tests including total viable count, psychrotrophic count and chemical tests including peroxide index, thiobarbituric acid, free fatty acid value and total volatile basic nitrogen, with sensory evaluation, were done at 4°C over a period of 15 days. The results showed that the black cumin extract delayed lipid oxidation and protein analyses significantly in treated fishes. Psycrotrophic bacteria and total viable count of samples being treated with black cumin extract were maintained lower than the proposed acceptable limit (7 log cfu/g). In comparison to the control samples, microbial spoilage significantly decreased in treated samples. Furthermore, according to sensory analysis, the treatment with black cumin extract led to high quality during storage.The findings indicated that black cumin exerts had strong antioxidant and antibacterial impacts on silver carp fish, such that the shelf life of fillets being treated with black cumin were 2.5 times more than that of control samples during storage in refrigerator

The Effect of Stevia Rebaudiana on Serum Omentin and Visfatin Level in STZ-Induced Diabetic Rats

Recently the role of adipocytokines in relationship to incidence of diabetes has been demonstrated. One of the medicinal plants that are used in the treatment of diabetes is stevia. This study investigates the effect of stevia on serum omentin and visfatin levels as novel adipocytokines in diabetic induced rats to find potential mechanisms for the anti hyperglycemic effect of stevia. Forty male wistar rats weighing 180–250 g were induced with diabetes by intraperitoneal injection of streptozotocin (STZ). The animals were divided into 5 groups of 8. Rats in group 1 (non-diabetic control) and group 2 (diabetic control) were treated with distilled water, and the rats in the treated groups, group 3 (T250), group 4 (T500), and group 5 (T750) were treated with stevia, gavaged every day at 9 a.m. in doses of 250, 500, and 750 mg/kg, respectively. At the end of the study significant reductions in fasting blood sugar (FBS), the homeostasis model assessment insulin resistance (HOMA-IR), triglyceride (TG), alkaline phosphatase (ALP), and Omentin level were found in groups 3 and 4 in comparison with group 2. Pancreatic histopathology slides demonstrated that stevia extract did not induce any increase in the number of β-cells. The conclusion is that prescription of stevia in the doses of 250 and 500 mg/kg/d decreases the omentin level indirectly via activating insulin sensitivity and lowering blood glucose in STZ-induced diabetic rats. KEYWORDS. Diabetes, omentin, stevia, visfati

Nucleotide sequence of cDNA encoding for preprochymosin in native goat (Capra hircus) from Iran

Summary Prochymosin is one of the most important aspartic proteinases used as a milk-clotting enzyme in cheese production. In the present investigation we report sequence of cDNA encoding goat (Capra hircus) preprochymosin and compare its nucleotide and deduced amino acid sequences with sequences of other ruminants preprochymosin. As bovine prochymosin, the caprine prochymosin cDNA encodes 365 amino acids with a prosegment of 42 amino acids and the mature goat chymosin begins with glycine. The preprochymosin nucleotide sequence reported in this study differs from other reported goat sequence (AY389343) in three nucleotides, two of which alter the amino acids at positions 19p and 139