Ti–6Al–4V is the most commonly used titanium alloy in aerospace, marine, and biomedical applications. Due to the properties of poor machinability in conventional machining, Electrical Discharge Machining (EDM) is considered a prospective alternative for machining this strategic material. This study aims at enhancing the performance of powder mixed EDM (PMEDM) in the machining of Ti–6Al–4V with the application of two different types of powders, namely Graphite (Gr) and Titanium Oxide (TiO2) powders, with different concentrations in dielectric—kerosene. The effect of these powers and their relative quantities are studied in terms of metal removal rate (MRR), tool wear rate, Surface Roughness, and surface integrity. Machining is performed using the copper electrode and kerosene as the dielectric medium. A separate container and a submersible pump are used to limit the quantity of powder and keep the powder in suspension, respectively. Design of experiments guided by Design-Expert software is employed to minimize the number of experimental runs and develop empirical models of response parameters in terms of the variable parameters—peak current, powder type, and powder concentration. Findings indicate that TiO2 powder has a much higher effect on MRR compared to graphite powder, as the maximum MRR in the case of TiO2 powder is recorded 41.01 mm3/min against 11.98 mm3/min for graphite powder, i.e., 3.42 times higher. Similarly, the tool wear ratio for TiO2 powder is 0.0704 against 0.1219 for graphite powder at the maximum MRR, which is 1.73 times lower compared to that of graphite powder. The same ratios at the minimum MRR for TiO2 is 0.0098, and for graphite power is 0.0282, which is again 2.88 times lower compared to that of graphite powder. In terms of average surface roughness, Ra, the performance of TiO2 is far better compared to graphite powder since the maximum surface roughness attained with TiO2 powder is 3.265 μm against 9.936 μm for graphite powder at the highest MRR and the same attained at the lowest MRR are 2.228 μm and 2.411 μm for TiO2 and graphite powders respectively. The mechanism of the effects of PMEDM on surface texture has also been observed using SEM images to study the influence of powder concentration on surface morphology.

Background The coronavirus disease 2019 (COVID-19) pandemic has manifested into an unprecedented public health crisis. The rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has facilitated reagent developers to customize and receive authorization for nucleic acid testing kits in a short period, which would have resulted in some shortcomings in the quality parameters of the kits. Consequently, in-house clinical validations of innovative real-time quantitative polymerase chain reaction (RT-qPCR) kits are required. This research aims to determine the sensitivity, specificity, and accuracy of various RT-qPCR kits available in Bangladesh. Methodology A total of 150 samples were obtained from patients with suspected COVID-19 infection when the delta variant was predominant, followed by RNA extraction performed using a nucleic acid isolation kit. Subsequently, three commercially available PCR kits named Sansure (China), STAT-NAT Ⓑ (Sentinel Diagnostics, Italy), and Roche Biochem (Switzerland) were applied to detect SARS-CoV-2. Results The results showed that the STAT-NAT Ⓑ kit is more sensitive than the other two, as indicated by the cycle threshold (Ct) values of respective genes. STAT-NAT Ⓑ RT-qPCR can detect the ORF1ab gene sensitively (p < 0.001) compared to Sansure. STAT-NAT Ⓑ was also capable of detecting E and RdRp genes more sensitively (p < 0.001) compared to Roche. Regarding specificity, STAT-NAT Ⓑ (95% confidence interval [Cl] = 92.29-99.73%). RT-qPCR showed more accuracy than Sansure (95% Cl = 90.77-99.32%) and Roche (95% Cl = 81.17-94.38%). The area under the curve for E , ORF1ab , and RdRp genes of the STAT NAT Ⓑ PCR kit was 0.952, 0.959, and 0.981, respectively. Conclusions This study concluded that STAT-NAT Ⓑ is a better diagnostic RT-qPCR kit compared to Sansure and Roche for detecting SARS-CoV-2.

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The study is planned to evaluate the financial strengths and weaknesses and to make suggestions to improve its financial position. The data are collected from secondary sources. To analyze financial performance some key variables are selected like liquidity Ratios, Solvency Ratios, Profitability Ratios and Activity Ratios. From the analysis and interpretation of data it was observed that the company’s managerial performance, profit earning capability etc. are in very good position. The reasons for these positions were due to proper management, planning and control of working capital, operational efficiency, adequate credit policy, high labor efficiency, good quality raw materials, good marketing forces, adequate and good storage facilities etc.

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