Modeling and optimization of process parameters in face milling of Ti6Al4V alloy using Taguchi and grey relational analysis

Titanium alloys are extensively used in aerospace, missiles, rockets, naval ships, automotive, medical devices, and even the consumer electronics industry where a high strength to density ratio, lightweight, high corrosion resistance, and resistance to high temperatures are important. The machining of these alloys has always been challenging for manufacturers. This article investigates the combined effect of radial depth, cutting speed and feed rate on cutting forces, tool life, and surface roughness during face milling of Ti6Al4V alloy. This study focuses on the significance of radial depth of cut on cutting force, tool life and surface roughness compared to that of cutting speed and feed rate during face milling of Ti6Al4V alloy. In this paper, mono and multi-objective optimization of the response characteristics have been conducted to find out the optimal input parameters, namely, cutting speed, feed rate, and radial depth of cut. Taguchi method and analysis of variance (ANOVA) analysis have been used for mono-objective optimization, while Taguchi-based grey relational analysis has been used for multi-objective optimization. The regression analysis has been performed for developing mathematical models to predict the surface roughness, tool life, and cutting forces. According to ANOVA analysis, the most significant parameters for tool life and cutting force (FY) are cutting speed, and radial depth of cut, respectively, while feed rate is observed to be the most significant parameter for surface roughness and force (FX). The optimal combination of input parameters for tool life and FY are 50m/min cutting speed, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. However, the optimal parameters for surface roughness are 65m/min cutting speed, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. For FX, the optimal condition is observed as cutting speed 57.5m/min, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. A validation experiment, conducted at the optimal parameters of surface roughness, shows an improvement of 31.29% compared to the surface roughness at initial condition. Taguchi-based grey relational analysis for multi-objective optimization shows an improvement of 55.81%, 6.12%, and 23.98% in tool life, surface roughness, and FY, respectively. ANOVA analysis based on grey relational grade shows that the radial depth of cut is the most significant parameter for multi-objective optimization during the face milling of Ti6Al4V

Analgesic and Antipyretic Activities of Methanol Extract and Its Fraction from the Root of Schoenoplectus grossus

The study aims to evaluate analgesic and antipyretic activities of the methanol extract and its different fractions from root of Schoenoplectus grossus using acetic acid induced writhing and radiant heat tail flick method of pain models in mice and yeast induced pyrexia in rats at the doses of 400 and 200 mg/kg. In acetic acid writhing test, the methanol extract, petroleum ether, and carbon tetrachloride fractions produced significant ( < 0.001 and < 0.05) inhibition of writhing responses in dose dependent manner. The methanol extract at 400 and 200 mg/kg being more protective with 54% and 45.45% of inhibition compared to diclofenac sodium of 56% followed by petroleum ether fractions of 49.69% and 39.39% at the same doses. The extracts did not produce any significant antinociceptive activity in tail flick test except standard morphine. When studied on yeast induced pyrexia, methanol and petroleum ether fractions significantly lowered the rectal temperature time dependently in a manner similar to standard drug paracetamol and distinctly more significant ( < 0.001) after second hour. These findings suggest that the root extracts of S. grossus possess significant peripherally acting analgesic potential and antipyretic property. The phytochemical screening showed the presence of flavonoids, alkaloids, and tannins

Pharmacological Evaluation of Naproxen Metal Complexes on Antinociceptive, Anxiolytic, CNS Depressant, and Hypoglycemic Properties

properly cited. Purpose. The present study was designed to investigate the antinociceptive, anxiolytic, CNS depressant, and hypoglycemic effects of the naproxen metal complexes. Methods. The antinociceptive activity was evaluated by acetic acid-induced writhing method and radiant heat tail-flick method while anxiolytic activity was evaluated by elevated plus maze model. The CNS depressant activity of naproxen metal complexes was assessed using phenobarbitone-induced sleeping time test and the hypoglycemic test was performed using oral glucose tolerance test. Results. Metal complexes significantly ( < 0.001) reduced the number of abdominal muscle contractions induced by 0.7% acetic acid solution in a dose dependent manner. At the dose of 25 mg/kg body weight p.o. copper, cobalt, and zinc complexes exhibited higher antinociceptive activity having 59.15%, 60.56%, and 57.75% of writhing inhibition, respectively, than the parent ligand naproxen (54.93%). In tail-flick test, at both doses of 25 and 50 mg/kg, the copper, cobalt, silver, and zinc complexes showed higher antinociceptive activity after 90 minutes than the parent drug naproxen. In elevated plus maze (EPM) model the cobalt and zinc complexes of naproxen showed significant anxiolytic effects in dose dependent manner, while the copper, cobalt, and zinc complexes showed significant CNS depressant and hypoglycemic activity. Conclusion. The present study demonstrated that copper, cobalt, and zinc complexes possess higher antinociceptive, anxiolytic, CNS depressant, and hypoglycemic properties than the parent ligand

A Case Study of Six Sigma Define-Measure-Analyze-Improve-Control (DMAIC) Methodology in Garment Sector

This paper demonstrates the empirical application of Six Sigma and Define-Measure-Analyze-Improve-Control (DMAIC) methodology to reduce product defects within a garments manufacturing organization in Bangladesh which follows the DMAIC methodology to investigate defects, root causes and provide a solution to eliminate these defects. The analysis from employing Six Sigma and DMAIC indicated that the broken stitch and open seam influenced the number of defective products. Design of experiments (DOE) and the analysis of variance (ANOVA) techniques were combined to statistically determine the correlation of the broken stitch and open seam with defects as well as to define their optimum values needed to eliminate the defects. Thus, a reduction of about 35% in the garments defect was achieved, which helped the organization studied to reduce its defects and thus improve its Sigma level from 1.7 to 3.4

The role of statins in prevention and treatment of community acquired pneumonia: a systematic review and meta-analysis.

BACKGROUND: Emerging epidemiological evidence suggests that statins may reduce the risk of community-acquired pneumonia (CAP) and its complications. PURPOSE: Performed a systematic review to address the role of statins in the prevention or treatment of CAP. DATA SOURCE: Ovid MEDLINE, Cochrane, EMBASE, ISI Web of Science, and Scopus from inception through December 2011 were searched for randomized clinical trials, cohort and case-control studies. STUDY SELECTION: Two authors independently reviewed studies that examined the role of statins in CAP. DATA EXTRACTION: Data about study characteristics, adjusted effect-estimates and quality characteristics was extracted. DATA SYNTHESIS: Eighteen studies corresponding to 21 effect-estimates (eight and 13 of which addressed the preventive and therapeutic roles of statins, respectively) were included. All studies were of good methodological quality. Random-effects meta-analyses of adjusted effect-estimates were used. Statins were associated with a lower risk of CAP, 0.84 (95% CI, 0.74-0.95), I(2) = 90.5% and a lower short-term mortality in patients with CAP, 0.68 (95% CI, 0.59-0.78), I(2) = 75.7%. Meta-regression did not identify sources of heterogeneity. A funnel plot suggested publication bias in the treatment group, which was adjusted by a novel regression method with a resultant effect-estimate of 0.85 (95% CI, 0.77-0.93). Sensitivity analyses using the rule-out approach showed that it is unlikely that the results were due to an unmeasured confounder. CONCLUSIONS: Our meta-analysis reveals a beneficial role of statins for the risk of development and mortality associated with CAP. However, the results constitute very low quality evidence as per the GRADE framework due to observational study design, heterogeneity and publication bias

Fabrication and mechanical/thermal properties of composites from cotton linter and urea formaldehyde resin

The aim of this study is to prepare composite from commercial valueless cotton linter cellulose (CLC) of textile mills and garment industries, and urea formaldehyde (UF) resin. The alkali-treated cellulose (ATC), bleached cellulose (BLC) and microcrystalline cellulose (MCC) have been prepared from CLC. A novel fabrication method of CLC, ATC, BLC and MCC reinforced with urea formaldehyde resin has been developed. These composites are subsequently subjected to evaluation of their mechanical (tensile, flexural, hardness) and thermal (TGA, DTA, DTG) properties. The MCC-UF composites show the highest tensile strength (TS), flexural strength (FS) and Vickers micro hardness number (VHN) having the corresponding values 48.09 MPa, 34.05 MPa and 521.33 VHN respectively. The lowest mechanical values are found for CLC-UF composites (TS 32.96 MPa, FS 21.28 MPa and VHN 201.00). It is also revealed that the mechanical properties of the composites increase with the increase in fibre loading up to 5% and beyond this loading, these values are decreased. The morphological changes in flexural fractured surface are clearly observed by scanning electron microscopy measurement. The thermal stability of the composites is influenced by the filler content. The thermal stability of MCC-UF composite is found slightly higher than those of other composites.

The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis.

Background Clostridium difficile infection (CDI) is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI. Purpose We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs) and CDI. Data source We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI. Study selection Two authors independently reviewed the studies for eligibility. Data extraction Data about studies characteristics, adjusted effect estimates and quality were extracted. Data synthesis Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22–1.7), I2 = 70.5%. This association was consistent across different subgroups (by study design and country) and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15–1.68), I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH) with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115) and 425, 95% CI (267, 848), respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097). Conclusion In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics

Association between proton pump inhibitor therapy and clostridium difficile infection: a contemporary systematic review and meta-analysis.

Abstract Introduction Emerging epidemiological evidence suggests that proton pump inhibitor (PPI) acid-suppression therapy is associated with an increased risk of Clostridium difficile infection (CDI). Methods Ovid MEDLINE, EMBASE, ISI Web of Science, and Scopus were searched from 1990 to January 2012 for analytical studies that reported an adjusted effect estimate of the association between PPI use and CDI. We performed random-effect meta-analyses. We used the GRADE framework to interpret the findings. Results We identified 47 eligible citations (37 case-control and 14 cohort studies) with corresponding 51 effect estimates. The pooled OR was 1.65, 95% CI (1.47, 1.85), I2 = 89.9%, with evidence of publication bias suggested by a contour funnel plot. A novel regression based method was used to adjust for publication bias and resulted in an adjusted pooled OR of 1.51 (95% CI, 1.26–1.83). In a speculative analysis that assumes that this association is based on causality, and based on published baseline CDI incidence, the risk of CDI would be very low in the general population taking PPIs with an estimated NNH of 3925 at 1 year. Conclusions In this rigorously conducted systemic review and meta-analysis, we found very low quality evidence (GRADE class) for an association between PPI use and CDI that does not support a cause-effect relationship