Multi Objective Optimization of Process Parameters by Firefly Algorithm during the Friction Stir Welding of Metal Matrix Composites

The use of composite materials in practical applications can be further enhanced by joining them effectively. In the current research, composites of Al 5083 reinforced with 10% B4C were prepared using the stir casting technique and were joined by friction stir welding. The process parameters, i.e. tool revolving speed, welding feed, and vertical plunge force were considered and taken in three levels to analyse their influence on mechanical properties, such as ultimate tensile strength and micro hardness. To make a joint, two tools with a square tool pin profile were machined, one coated with titanium nitride (TiN) and the other with diamond like carbon (DLC).Experiments were planned as per Box - Behenken’s design which suggested 15 experiments to analyse the output response. A mathematical model was developed for each output response for both the tools and the reliability of the model was confirmed by conducting the ANOVA test. The effect of varying each parameter on output parameters was studied and compared for both tools. Multi objective optimization was done by the firefly algorithm using the MATLAB 2018a software. For the TiN coated tool, maximum tensile strength of 133.92 MPa and Vickers micro hardness value of 102.54 were obtained with the following process parameters: 1540 rpm, 20 mm/min, 6 KN. As far as the DLC tool is concerned, the maximum values obtained are 129.67 MPa and 102.47 with the following parameters: 1360 rpm, 55 mm/min, and 8 KN

ChemInform Abstract: Synthesis of Boc‐Amino Tetrazoles Derived from α‐Amino Acids

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option

ChemInform Abstract: Synthesis of Ureido‐Linked Glycosylated Amino Acids from Nα‐Fmoc‐Asp/Glu‐5‐oxazolidinones and Their Application to Neoglycopeptide Synthesis

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option

Synthesis of tetrazole analogs of amino acids using Fmoc chemistry: isolation of amino free tetrazoles and their incorporation into peptides

An efficient synthesis of tetrazole analogs of amino acids starting from Nα-​Fmoc amino acid (Fmoc = 9-​fluorenylmethoxycarbonyl) in a three-​step protocol is reported. The free amino tetrazoles were obtained in good yields and with excellent purity after removal of the Fmoc group. The synthesis of analogs of aspartic and glutamic acids in which the 5-​tetrazolyl moiety is inserted at the β​/γ carboxyl group starting from Fmoc-​Asn and Fmoc-​Gln and the incorporation of these tetrazoles into peptides are also described

Mathematical Modeling for Radial Overcut on Electrical Discharge Machining of Incoloy 800 by Response Surface Methodology

AbstractIn the present study, Response surface methodology is applied for prediction of radial overcut in die sinking electrical discharge machining (EDM) process for Incoloy 800 superalloy with copper electrode. The current, pulse-ontime, pulse-off time and voltage are considered as input process parameters to study the ROC. The experiments were planned as per central composite design (CCD) method. After conducting 30 experiments, a mathematical model was developed to correlate the influences of these machining parameters and ROC. The significant coefficients were obtained by performing ANOVA at 5% level of significance. From the obtained results,It was found that current and voltage have significant effect on the radial overcut. The predicted results based on developed models are found to be in good agreement with the The predicted values match the experimental results reasonably well with the coefficient of determination 0.9699 for ROC

Synthesis of 1,​1-​dioxobenzo[b]​thiophene-​2-​ylmethyloxycarbonyl (Bsmoc) protected N-​methyl amino acids by reduction of Bsmoc-​5-​oxazolidinones and their use in peptide synthesis

The synthesis of Bsmoc-​N-​Me amino acids is presented. The first step involves p-​toluenesulfonic acid (TsOH) catalyzed condensation of a Bsmoc-​amino acid with paraformaldehyde to furnish N-​Bsmoc-​5-​oxazolidinone under MW irradn. This intermediate is reduced to the corresponding N-​Me amino acid using triethylsilane (Et3SiH) and trifluoroacetic acid (TFA) at room temp. The N-​Me amino acids are converted into corresponding acid fluorides using diethylaminosulfur trifluoride (DAST) and employed as coupling agents in the synthesis of dipeptides. The peptide coupling was mediated by KOAt in CH2Cl2

Relative Roles of TGF-β and IGFBP-5 in Idiopathic Pulmonary Fibrosis

Although most evident in the skin, the process of scarring, or fibrosis, occurs in all major organs because of impaired epithelial self-renewal. No current therapy exists for Idiopathic pulmonary fibrosis. The major profibrotic factor is TGF-β1 and developing inhibitors is an area of active research. Recently, IGFBP-5 has also been identified as a profibrotic factor, and studies suggest that, while both TGF-β1 and IGFBP-5 activate mesenchymal cells to increase collagen and fibronectin production, their effects on epithelial cells are distinct. TGF-β1 induces cell death and/or EMT in the epithelial cells, exacerbating the disruption of tissue architecture. In contrast, IGFBP-5 induces epithelial cell spreading over collagen or fibronectin matrices, increases secretion of laminin, the epithelial basement membrane, and enhances the survival of epithelial cells in nutrient-poor conditions, as exists in scar tissue. Thus, IGFBP-5 may enhance repair and may be an important target for antifibrotic therapies

Diethyl 3,4-bis­(2,5-dimethoxy­benz­yl)thieno[2,3-b]thio­phene-2,5-di­car­boxylate

In the title compound, C30H32O8S2, the dihedral angle between the two benzene rings is 18.8 (1)°. The mol­ecular structure is stabilized by weak intra­molecular C—H⋯O hydrogen bonds. In the crystal structure, the mol­ecules are linked via weak inter­molecular C—H⋯O hydrogen bonds and π–π inter­actions between two benzene rings [centroid–centroid distance = 3.672 (1) Å]

Ethyl 2-acetoxy­methyl-1-phenyl­sulfonyl-1H-indole-3-carboxyl­ate

In the title compound, C20H19NO6S, the phenyl ring of the phenyl­sulfonyl group makes a dihedral angle of 83.35 (5)° with the indole ring system. The mol­ecular structure exhibits a number of short intramolecular C—H⋯O contacts

Diethyl 3,4-bis(acetoxy­meth­yl)thieno[2,3-b]thio­phene-2,5-dicarboxyl­ate

In the title compound, C18H20O8S2, the dihedral angle between the two thio­phene rings is 2.33 (7)°. The methyl C atoms of the ester groups are disordered over two positions; the site-occupancy factors of the terminal methyl C atoms are 0.632 (18):0.368 (18) and 0.623 (17):0.377 (17). The mol­ecular structure is stabilized by weak intra­molecular C—H⋯O inter­actions and the crystal structure is stabilized through weak inter­molecular C—H⋯O inter­actions