The present investigation centered on the application of response surface methodology to assess the engine operating parameters namely performance, combustion, emission, and vibration characteristics of variable compression ratio direct injection single-cylinder diesel engine operating with Niger seed oil methyl ester blend and hydrogen in dual fuel mode. Response surface models were developed using the experimental data of input and output variables. The fuel blend, load, compression ratio, and hydrogen flow rate were considered as input responses while the brake thermal efficiency, brake specific fuel consumption, cylinder pressure and net heat release rate, carbon monoxide (CO), unburnt hydrocarbon, Nitrogen oxides (NO x), smoke opacity, and RMS velocity respectively were considered as the output responses. The input conditions altered were: loads of 29.43 N (3 kgf), 58.86 N (6 kgf), 88.29 N (9 kgf), and 117.72 N (12 kgf), compression ratios of 16, 17.5, and 18.5, and the hydrogen flow rates of 5 lpm, 10 lpm, and 15 lpm. The output information of the test was assessed using response surface methodology (RSM) and the polynomial model (second-request) was created. The experimental values were in good match with RSM predicted values and maintained an R 2 value of more than 0.95 for all the test run combinations. Further, all the test points sustained comparatively within the 10% maximum deviation. Keywords Brake thermal efficiency • Compression ratio • Smoke opacity • Hydrogen • Cylinder pressure Abbreviations CR Compression ratio FB Fuel blend HFR Hydrogen flow rate (lpm) BTE Brake thermal efficiency (%) BSFC Brake specific fuel consumption (kg/kWhr) NSOME Niger seed oil methyl ester B20 20% NSOME in diesel CO Carbon monoxide (%) UHC Unburnt hydrocarbon (ppm) NOx Nitrogen oxides (ppm) CI Compression ignition ASTM American standards for testing materials ADC Analog to digital converter lpm Liter per minute CP Cylinder pressure (bar) NHRR Net heat release rate (J/deg.) q Net heat release rate (J/deg.) q Heat Heat transfer rate combustion chamber wall (J/deg.) V Volume change with crank angle (m 3 /deg.) p Pressure change with crank angle (bar/deg.)
The main objective of the present study was to develop and validate a multicomponent analysis of Darunavir, Cobicistat, Emtricitabine and Tenofovir alafenamide in bulk drug and pharmaceutical dosage form by ultra-performance liquid chromatography (UPLC). The drugs were separated using HSS C18 (100mm × 2.1mm, 1.8µ particle size) column with mobile phase consisting of potassium dihydrogen phosphate, pH adjusted to 5.4 and acetonitrile in the composition of 60:40 %v/v operated in isocratic mode at a flow rate of 0.3 ml/min. The column temperature maintained at 30˚C and detection wavelength used was 260 nm. The retention time for Darunavir was found to be 1.04min, for Cobicistat it was 1.82 min, for Emtricitabine it was 2.28 min and for Tenofovir it was found to be 1.39min. The developed method was validated in accordance to the ICH guidelines. The method obeyed Beer’s law in the concentration range of 50 µg/ml- 300µg/ml for Darunavir, 7.5 µg/ml – 45 µg/ml for Cobicistat, 25µg/ml - 150µg/ml for Emtricitabine and 0.625 µg/ml – 3.75µg/ml for Tenofovir alafenamide, with correlation coefficient of 0.999. The % relative standard deviation for all the drugs was found to be less than two indicating the method to be precise. The mean % recovery was found to be within the limits for all the drugs indicating that the method to be accurate. The method was also found to be specific, robust and stable. From the forced degradation studies, it was concluded that the drugs were found to be stable when exposed to different stress conditions as the net degradation was found within the acceptance criteria. The developed method for the multicomponent analysis of Darunavir, Cobicistat, Emtricitabine and Tenofovir alafenamide using UPLC can be used for quality control and routine analysis in bulk drug and pharmaceutical dosage form.
The main objective of proposed method is to develop, validate & to perform the forced degradation studies for the simultaneous quantification of lamivudine, doravirine and tenofovir in active pharmaceutical ingredient (API) and formulation using reverse phase ultra-performance liquid chromatography (RP-UPLC). The estimation was performed using HSS C18 (100mm×2.1mm,1.8µ)column with acetonitrile and 0.1 % ortho phosphoric acid (OPA) (35:65) as mobile phase ran in isocratic mode at rate of flow 0.3ml/min. The column temperature maintained at 30°C and detection wavelength used was 260nm. The developed method validated as per ICH guidelines. Method obeyed Beer’s law in the range of concentration of 37.5µg/ml – 225µg/ml, 37.5µg/ml – 225µg/ml and 12.5µg/ml – 75µg/ml for lamivudine, tenofovir and doravirine respectively. The method is stable when exposed to different stressed conditions with less degradation. For regular analysis of estimate of lamivudine, tenofovir, and doravirine in tablet formulation, this UPLC method can be employed
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