525 research outputs found

    Unsteady Flow Effects in Combustor Systems

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    A wide variety of combustion problems, including combustion instabilities and turbulent diffusion flames, appear to involve the entrainment and deformation of laminar flames by large vortex structures in the flow field. First, some details of this process of laminar flame distortion are examined by considering the interactions of time-dependent diffusion flames with two dimensional vortices. Second, Some results on the modelling of the non-steady combustion in burners for aircraft gas turbines are given. The general aim of the work is to develop a one dimensional model applicable to the NASA-Lewis Non-Steady Combustion Rig

    Application of Taguchi approach and Utility Concept in solving the Multi-objective Problem when

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    The traditional Taguchi method is widely used for optimizing the process parameters of a single response problem. Optimizationof a single response results the non-optimum values for remaining. But, the performance of the manufactured products isoften evaluated by several quality characteristics/responses. Under such circumstances, multi-characteristics response optimizationmay be the solution to optimize multi-responses simultaneously. In the present work, a multi-characteristics responseoptimization model based on Taguchi and Utility concept is used to optimize process parameters, such as speed, feed, depthof cut, and nose radius on multiple performance characteristics, namely, surface roughness (Ra) and material removal rate(MRR) during turning of AISI 202 austenitic stainless steel using a CVD coated cemented carbide tool. Taguchi’s L8 orthogonalarray (OA) is selected for experimental planning. The experimental result analysis showed that the combination of higherlevels of cutting speed, depth of cut, and nose radius and lower level of feed is essential to achieve simultaneous maximizationof material removal rate and minimization of surface roughness. The ANOVA and F-tests are used to analyze the results.Further, the confirmation tests are conducted and the results are found to be within the confidence interval

    Ionic mass transfer at point electrodes located at cathode support plate in an electrorefining cell in presence of rectangular turbulent promoters

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    Current density plays a major role in deciding the plant size, current efficiency, and energy consumption in electrorefining cells. In general, operating current density will be 40% of the limiting current density. Forced circulation of the electrolyte in the presence of promoters improves the mass transfer coefficient. In the present study, rectangular turbulence promoters are fitted at the bottom side of the cell to improve the mass transfer coefficient at the cathode support plate. The limiting current density technique is used to measure the mass transfer coefficient. The variables covered in the present study are the effects of flow rate, promoter height, and spacing among the promoters. The electrolyte consists of copper sulfate and sulphuric acid. At a regulated flow rate, the electrolyte is pumped from the recirculation tank to the cell through an intermediate overhead tank. The limiting current density increased with an increasing flow rate in the presence of promoters, and thus the overall mass transfer coefficient on the cathode support plate also improved. With an increase in the flow rate of the electrolyte from 6.67 × 10−6 to 153.33 m3/s, limiting current density increased from 356.8 to 488.8 A/m2 for spacing of 0.30 m, with a promoter height of 0.01 m. However, it is noteworthy that when the promoter height is increased from 0.01 to 0.07 m, the overall mass transfer coefficient is found to increase up to 60%, but with the further increase in the promoter height to 0.30 m the mass transfer coefficient starts to decrease. Therefore, the optimized cell parameters are established in this work. The current sustainable concept of employing rectangular turbulence promoters will bring benefits to any precious metal refining or electrowinning tank house electrolytes

    ANALYTICAL STANDARDIZATION OF RAJATA BHASMA

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    Bhasma Kalpana is a unique part of Ayurvedic Rasa shastra. It is a method of converting metals into metallic Bhasma. Metallic Bhasmas are well known for its quick effectiveness, smaller dose and a long shelf life. However if these Bhasmas are not well prepared and analyzed they can be toxic to human body. Therefore Bhasma Pariksha is given in Ayurveda to confirm the well prepared metallic Bhasma, but in this era we need to analyze the Bhasmas on modern parameters too to make it acceptable globally. So in this study prepared Rajata (Silver) Bhasma is analyzed on various parameters i.e. Ayuvedic parameters i.e., Varitaratwa, Rekhapurnatwa, Slakshantwa and Laghutwa and some modern parameters like, pH, Particle size, Zeta Potential, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray spectroscopy, Fourier Transform Infra red Spectroscopy (FTIR), U V – Spectroscopy. Results: pH value is 5.6, UV- spectroscopy showed maximum absorption at 302nm, FT-IR of Rajata bhasma reveals the presence of C-H (alkyl), C-N (Aliphatic amine) groups at different wavelengths, Mean Particle size of Rajata bhasma is 2.7nm, Zeta Potential analysis reveals -19.3 mV, X-RD of Rajata bhasma reaveals the major peaks of HgS (Cinnabar), Ag2S (Silver Sulphide), SEM analysis of Rajata bhasma showed small crystalline particles at 5KX & 10KX magnifications, EDX analysis of Rajata bhasma confirmed the presence of elements viz., Sulphur 20.34%, Oxygen 7.43%, Silver 26.72%, Mercury 45.51% by weight

    Dual effect of anionic surfactants in the electrodeposited MnO2 trafficking redox ions for energy storage

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    The dual effect of in-situ addition of anionic surfactants, sodium octyl sulfate (SOS), sodium dodecyl sulfate (SDS) and sodium tetradecyl sulfate (STS) on the microstructure and electrochemical properties of electrolytic manganese dioxide (EMD) produced from waste low grade manganese residue is discussed. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), BET-surface area studies, thermogravimetry-differential thermal analysis (TG-DTA) and Fourier transform infrared spectroscopy (FTIR) were used to determine the structure and chemistry of the EMD. All EMD samples were found to contain predominantly gamma-phase MnO2, which is electrochemically active for energy storage applications. FESEM images showed that needle, rod and flower shaped nano-particles with a porous surface and platy nano-particles were obtained in the case of EMD deposited with and without surfactant respectively. Thermal studies showed loss of structural water and formation of lower manganese oxides indicating high stability of the EMD samples. The cyclic voltammetry and charge - discharge characteristics implied the presence of surfactants enhances the energy storage within the MnO2 structure. Addition of the surfactant at its optimum concentration greatly increased the EMD surface area, which in turn improved the cycle life of the EMD cathode. EMD obtained in the presence of 25, 50, 25 ppm of SOS, SDS, and STS respectively showed an improved cycle life relative to the EMD obtained in the absence of surfactant. EMD obtained without surfactant showed a capacity fade of 20 mAh g(-1) within 15 discharge-charge cycles, while surfactant modified samples showed stable cyclic behavior of capacity 95 mAh g(-1) even after 15 cycles

    INSIGHT OF METHANOLIC EXTRACT OF VENTILAGO MADERASPATANA LEAVES ON HEPATOPROTECTIVE ACTIVITY UNDER STREPTOZOTOCIN-INDUCED DIABETIC RATS

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    Objective: The methanolic leaf extract of Ventilago maderaspatana (MEVML, 200 mg/kg body weight [b.w.]) was investigate to hepatoprotective activity under streptozotocin-induced (45 mg/kg b.w.) diabetic (Di) rats. Methods: In the present study, we determined the blood glucose levels, b.w., insulin, creatinine, and bilirubin levels in normal, Di, Di treated with MEVML and positive control rats. Results: The Di rats shown adverse changes in blood glucose levels, b.w., insulin, creatinine, and bilirubin levels when compared to other group rats. Reverse the adverse changes in the above parameters when treated the Di rats with MEVML Conclusion: The MEVML shown anti-diabetic activity and reverse the adverse changes in the above parameters in liver so that the MEVML supported the traditional claim of the hepatoprotective activity under Di condition

    A RETROSPECTIVE STUDY ON THALASSEMIA IN SOUTH INDIAN TERTIARY CARE TEACHING HOSPITAL

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    Thalassemia syndromes are a heterogeneous group of disorders caused by inherited mutations that decrease the synthesis of adult haemoglobin, Hb-A [alpha2 beta2]. Depending on whether the genetic defect or deletion lies in transmission of alpha or beta globin chain genes, thalassemia are classified in to Alpha and Beta Thalassemia. Materials and methods: A Retrospective study was carried out in RIMS Kadapa for two months. Patient demographic details, type of thalassemia, prevalence of thalassemia, Hb levels, known & new cases were collected. Results: A total of 139 cases were diagnosed as having thalassemia in between February 2017 – March 2017. Among which 55 cases were seen in between 11-15 years followed by 6-10 years [38cases] later 0-5 years [38 cases] , 16-20 years [2 cases] 31-35 years[1case]. Highest number of cases was observed in males [91 cases] than females [48]. In our study we couldn't identify type of thalassemia in 122 cases as it was not written in the case sheets. Conclusion: There is a urgent need for making the people aware of this threatening disease Thalassemia, as this disease increasing day by day in the population silently. Health education programmers in the society may reduce the burden of the disease. Moreover, the complications of Thalassemia are one of the major problem on which one has to focus. Diagnosis of Thalassemia, treatment in the early phase may reduce the economic burden and complications in the society. Key words: Alpha thalassemia, Beta thalassemia, RBC destruction, Anemia

    Ocimum sanctum: a review on the pharmacological properties

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    Herbal medicine, the backbone of traditional medicine in many countries have played an important role in curing the diseases of humans since ancient time. Medicinal plants are great source of bioactive compounds and chemical structures that have potential beneficial effects. The present review compiles information on ethnopharmacologically useful information and pharmacological properties of Ocimum sanctum. Ocimum sanctum (OS) has many medicinal properties like antioxidant, antidiabetic, antiulcer, anticancer, antibacterial, antifungal and other. The phytochemicals compounds of Ocimum, alkaloids, flavonoids, phenolics, essential oils, tannins and saponins play an important role in herbal medicine. Bioactive compounds of Ocimum responsible for its various medicinal properties and their effects at the molecular level need to be investigated in more detail. Furthermore, pharmacological properties of bioactive compounds in Ocimum sanctum are required to confirm the ethnomedicinal claims of Ocimum sanctum for pharmaceutical therapeutic applications

    Performance of no-till maize under drip-fertigation in a double cropping system in semi arid Telangana state of India

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    Availability of water for Agriculture is becoming increasingly difficult, besides the cost of power for applying it. Improving the water and nitrogen use efficiency has become imperative in present day’s Agriculture. Drip irrigation and fertigation provides the efficient use of limited water with increased water and nutrient use efficiency, respec- tively. A field experiment was conducted during post rainy season of two consecutive years (2011 and 2012), in sandy loam soils of Warangal, Telangana State, India to study the response of no-till maize (Zea mays L) after aerobic rice (Oryza sativa L) to drip irrigation and nitrogen fertigation under semi-arid environment. The experiment was laid out in split plot design with four replications. Three irrigation schedules viz. drip irrigation at 75% Pan Evaporation (PE); 100% PE and 125% PE were taken as main plots and three nitrogen levels through fertigation viz. 120, 160, and 200 kg ha-1 as sub plots. The growth parameters (plant height, LAI, drymatter accumulation), root volume and dry weight, yield attributes (cobs plant-1, kernels cob-1, kernel weight cob-1) kernel yield, stover yield and nitrogen uptake of no till maize increased with increase in water input from 75% PE to 100% PE irrigation schedule in drip irrigation but could not reach the level of significance at 125% PE. Tasseling and silking was hastened in 125% PE schedule. Increase in the level of N application through fertigation from 120 to 160 kg N ha-1 resulted in the increase of all the growth parameters, yield attributes, kernel yield, stover yield and nitrogen uptake. Barrenness and test weight were unaffected by either the irrigation schedules or nitrogen levels. The economic indicators (gross returns, net returns and net benefit: cost ratio) were higher with the irrigation schedule of 125% PE and nitrogen dose of 200 kg N ha-1 applied through fertigation. Increased water input from 75 to 125% PE resulted in decreased water use efficiency but enhanced nitrogen use efficiency while the reverse trend was found with respect to N levels under fertigation
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