Evaluation of Mechanical and Metallurgical Properties of Dissimilar Materials by Friction Welding

AbstractFriction welding has been widely used to metals with dissimilar materials due to solid state joining process and shows good mechanical properties. In this study, the effect of mechanical and metallurgical properties of austenitic stainless steel (304L) and copper were experimentally investigated by tensile and hardness test while the metallurgical properties of optical, scanning electron microscopy and atomic force microscopy was used to analyze the microstructure of the welded joint. The joints were also examined with EDX line in order to understand the phases formed during welding. The material is evaluated by tensile test and their strength is determined and the hardness test measurements are examined in base metal and heat affected zone. The bonded materials of austenitic stainless steel and copper joint were produced by varying the friction pressure, upset pressure and rotational speed through Taguchi's orthogonal array. The highest tensile strength obtained in friction welded joint was 2.52% higher than parent material of copper. The effects of metallurgical characterization are discussed based on the microstructural studies

Bearing fault analysis using kurtosis and wavelet based multi-scale PCA

The vibration signal monitoring that is being generated by a rotor supported by a rolling element bearing is becoming important to define reliability of rotary machine. It is most prudent and useful method for bearing fault detection. Recently, there has been a lot of research on rolling element bearings fault. The kurtosis is most vital parameter to find inner race fault and outer race fault. It is enhanced by a proper selection of variable frame sizes and decompositions levels using wavelet based multi-scale principal component analysis (WMSPCA). It is observed that the kurtosis changes significantly as compared to the actual kurtosis of the un-decomposed faulty signals by proper selection of frame size and decompositions level

Utilization of chlorophyll content index (CCI) to infer yellow rust severity in wheat (Triticum aestivum L.)

Stripe rust caused by Puccinia striformis Westend. f. sp. tritici Eriks. (Pst) is a major constraint to wheat production in Northern India. In this study, 616 indigenous germplasm (IC) accessions of wheat were screened under field conditions against mixture of Pst isolates at DWR Karnal during 2012-13 crop season. Out of 616 accessions, 197 accessions were observed to be resistant (R), 115 moderately resistant (MR) to moderately susceptible (MS) and 304 as susceptible (S) against yellow rust. On the basis of days to heading, the accessions were grouped into four classes (early, medium early, medium late and late). Chlorophyll content index (CCI) recorded in flag leaf showed significant differences between resistant and susceptible lines in each classified group at 5% level of significance. The difference for CCI between resistant and moderately resistant plants was negligible, however in comparison with resistant plants, susceptible plants showed loss of 35-39% of chlorophyll. There was negative correlation (a correlation coefficient of – 0.60) between chlorophyll content and disease severity due to stripe rust in susceptible accessions

Protective Effect of Quercetin Against Sulphur Mustard-inducedOxidative Stress in Mice

Sulphur mustard (SM) is a chemical warfare agent that causes serious blisters upon contactwith human skin.  SM alkylates DNA and several other macromolecules, and also induces oxidativestress.  Quercetin, a bioflavonoid has wide pharmacological actions. The protective efficacy ofquercetin (100 mg/kg, i.p. and 200 mg/kg, i.p.) was studied by administering three doses in miceagainst SM.  The first dose was administered at 30 min prior, simultaneous, 2 h post or 24 h post,and two more doses on the next two days.  SM was administered (in PEG 300) percutaneouslyat varying doses for survival and protection studies.  SM was also administered at a dose of2 LD50 (19.3 mg/kg) with and without quercetin treatment and various biochemical markers wereestimated 7 days after SM administration.  Histological examinations of vital organs were alsocarried out. The animals administered with SM died at various days depending upon the dose.The body weight decreased significantly. Quercetin protected the mice significantly, in a dose-dependent manner. The protection was better when the first dose of quercetin administered was30 min prior or simultaneously.  A significant decrease in reduced as well as oxidised glutathioneand an increase in malondialdehyde, WBC count, RBC count, and haemoglobin were observedwith 2 LD50 SM. Quercetin at 100 mg/kg and 200 mg/kg doses significantly protected the biochemicalmarkers when the first dose of quercetin administered was 30 min prior or as simultaneoustreatment.  The histological lesions induced by sulphur mustard on liver, spleen, and skin werealso significantly protected by quercetin when the first dose was administered 30 min prior oras simultaneous treatment. The present study shows that percutaneous administration of SMinduces oxidative stress and quercetin can protect it as a prophylactic agent

Bioabsorbable screws versus metallic interference screw fixation in anterior cruciate ligament reconstruction using hamstring autograft: comparative analysis of functional outcome

Background: This prospective comparative study aimed to evaluate the functional outcomes of bioabsorbable screws versus titanium interference screws for anterior cruciate ligament (ACL) reconstruction using hamstring autograft. Methods: The study included 30 patients who underwent ACL reconstruction with a quadrupled hamstring graft; 15 were fixed with titanium interference screws and 15 with bioabsorbable screws. The patients were followed up for six months post-surgery. The functional outcomes were evaluated using the Lysholm score. The data were analyzed using SPSS version 22.0. Results: There was no significant difference in the functional outcomes between the two groups at the six-month follow-up. Conclusions: Our study shows that there was no difference in functional outcome whether bioabsorbable or titanium interference screw was used. The success of ACL reconstruction depends on the correct technique used for the surgery, precise placement of graft and rehabilitation methods than on type of graft fixation device used, neither titanium nor bioabsorbable screws

Highly efficient induced pluripotent stem cell reprogramming of cryopreserved lymphoblastoid cell lines

Tissue culture based in-vitro experimental modeling of human inherited disorders provides insight into the cellular and molecular mechanisms involved and the underlying genetic component influencing the disease phenotype. The breakthrough development of induced pluripotent stem cell (iPSC) technology represents a quantum leap in experimental modeling of human diseases, providing investigators with a self-renewing and thus unlimited source of pluripotent cells for targeted differentiation into functionally relevant disease specific tissue/cell types. The existing rich bio-resource of Epstein-Barr virus (EBV) immortalized lymphoblastoid cell line (LCL) repositories generated from a wide array of patients in genetic and epidemiological studies worldwide, many of them with extensive genotypic, genomic and phenotypic data already existing, provides a great opportunity to reprogram iPSCs from any of these LCL donors in the context of their own genetic identity for disease modeling and disease gene identification. However, due to the low reprogramming efficiency and poor success rate of LCL to iPSC reprogramming, these LCL resources remain severely underused for this purpose. Here, we detailed step-by-step instructions to perform our highly efficient LCL-to-iPSC reprogramming protocol using EBNA1/OriP episomal plasmids encoding pluripotency transcription factors (i.e., OCT3/4, SOX2, KLF4, L-MYC, and LIN28), mouse p53DD (p53 carboxy-terminal dominant-negative fragment) and commercially available reprogramming media. We achieved a consistently high reprogramming efficiency and 100% success rate (\u3e 200 reprogrammed iPSC lines) using this protocol