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  • Author: Raj Kumar x
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Parametric studies and simulation of PSA process for oxygen production from air

A numerical simulation and parametric studies for the separation of air using 5A zeolite for the production of oxygen are presented for a basic two bed pressure swing adsorption (PSA) process. The simulation is based on an in-house program ‘PSASOL’ developed in MATLABR. The transient process of PSA has been described by a set of partial differential equations, which were solved using a finite difference method. Simulation results have been validated with the experimental data from literature.

Based on the simulation results, an optimal set of operational parameter values has been obtained for the PSA bed. The values of the optimal parameters, viz. adsorption pressure, cycle time, feed rate, and product rate have been found to be 2.5 atm, 150 s, 15 cm3/s, and 2.55 cm3/s, respectively. For the optimal conditions, purity of 95.45% and recovery of 77.3% have been achieved. It has also been found that a longer tubular unit with the length to diameter (L/D) ratio of 10.5 is advantageous. The estimated pressure drop across the bed has been found to be negligible. Power consumption and productivity have also been computed.

Abstract

The Electrochemical discharge machining (ECDM) is a hybrid non-traditional process which is specifically used for machining of conducting as well as non-conducting materials. In this research work, the fabricated ECDM experimental setup was used to machine the Soda-lime glass material with Brass tool material. The experiments were done on Soda-lime glass material with the help of Taguchi L27 orthogonal array method and analysed by using MINITAB 17 software. The average hole diameter and average machined depth results were checked after ECDM drilling on Soda-lime glass material with considering the input process parameters such as an electrolyte concentration, voltage and rotation. The experimental results indicated that voltage was the most dominant factor for average machined depth followed by an electrolyte concentration and rotation speed. The rotation speed was the most dominant factor for average hole diameter followed by voltage and electrolyte concentration.

Abstract

Acute respiratory distress syndrome (ARDS) is a life threatening condition characterized by severe hypoxemia due to pulmonary gas exchange failure and was first recognized in 1960s.Since its first description, it has undergone intensive research in the past few decades to understand its pathogenesis and therapies. Despite this, the recommended therapies to decrease mortality in ARDS remain limited and include low-tidal volume mechanical ventilation, prone ventilation and recently, the ECMO rescue therapy in extreme cases. This review article will summarize the key features of ARDS with a brief overview of the therapeutic options in the management of ARDS.

Abstract

Survival of critically unwell patients has improved in the last decade due to advances in critical care medicine. Some of these survivors develop cognitive, psychiatric and /or physical disability after treatment in intensive care unit (ICU), which is now recognized as post intensive care syndrome (PICS). Given the limited awareness about PICS in the medical faculty this aspect is often overlooked which may lead to reduced quality of life and cause a lot of suffering of these patients and their families. Efforts should be directed towards preventing PICS by minimizing sedation and early mobilization during ICU.All critical care survivors should be evaluated for PICS and those having signs and symptoms of it should be managed by a multidisciplinary team which includes critical care physician, neuro-psychiatrist, physiotherapist and respiratory therapist, with the use of pharmacological and non-apharmacological interventions. This can be achieved through an organizational change and improvement, knowing the high rate of incidence of PICS and its adverse effects on the survivor’s life and daily activities and its effect on the survivor’s family.

Abstract

Four binary polymer -solvent systems, poly(styrene)-tetrahydrofuran, poly(styrene) - p-xylene, poly(methyl methacrylate) - ethylbenzene and poly(methyl methacrylate) - tetrahydrofuran, systems have been studied. It has been observed that thicker coatings will retain a higher amount of the residual solvent as compared to thinner coatings. In the case of poly(styrene)-tetrahydrofuran coating residual solvent remaining within the coatings were 9.09% and 4.74% for the coatings of the thicknesses of 967 micron and 559 micron, respectively. Similar trends were also observed in the case of poly(methyl methacrylate)-ethylbenzene, poly(methyl methacrylate)-tetrahydrofuran, and poly(styrene)-p-xylene systems.

Abstract

A rare complication associated with the Hodgkin’s lymphoma is the occurrence of persistent or recurrent hypoglycemia. Although few cases have been reported in the literature, describing its pathophysiology to be multifactorial, it is difficult to determine the exact cause. We present the case of a 26 year old patient diagnosed with Hodgkin’s lymphoma who developed recurrent episodes of hypoglycemia and also discuss the various causes for its pathogenesis. In this case the serum insulin and C-peptide levels were found to be low, suggesting the presence of insulin like growth factors (IGF) secreted by the cancer cells. Also, we performed a18F-2-fluoro-2-deoxy-d-glucose positron emission tomography that showed a massive tumor load. The published reports in literature have similary suggested the presence of IGF or auto-antibodies secreted by the tumor cells and also the Warburg effect in patients with high tumor load. Further research is required to clearly diagnose and define the exact etiopathogenesis of the hypoglycemia occurring in a patient with Hodgkin’s lymphoma.

Abstract

In the present paper we define some classes of double lacunary sequence spaces over n-normed spaces by means of a Musielak- Orlicz function. We study some relevant algebraic and topological properties. Further some inclusion relation among the classes are also examined.

Abstract

Anemia in patients admitted to an intensive care unit is common and affects almost all critically ill patients. The intensivist is faced with the challenge of treating multifactorial etiologies, mainly bleeding and blood loss due to phlebotomy and decreased erythropoiesis. Red cell transfusion, the most common treatment for anemia, comes with associated risks, which may further reduce the chance of survival of these patients. The best evidence suggests the practice of restrictive RBC transfusion (transfusion at Hb<7 g/dl).

In this article, the etiopathogenesis of the anemia in critically ill is reviewed, and current opinion on the pros and cons of various management strategies are discussed with emphasize on restrictive transfusion policy.

Abstract

Extracorporeal Membrane Oxygenation (ECMO) is now a recognized revolutionary technology, which has emerged as a life-saving therapeutic option for patients with potentially reversible severe respiratory failure who fail to respond positively with the conventional ventilation therapy. Severe acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality, and ECMO has been proven to increase the survival rates in these patients by improving the gas exchange and thus preventing the further hypoxia and catecholamine induced multi-organ damage. The authors present a case of H1N1 influenza related severe ARDS who was successfully rescued by the early use of ECMO. The authors recommend the early use of ECMO to be incorporated in the management of severe refractory ARDS caused due to a potentially reversible cause.

ABSTRACT

The mission to make humans less attractive to mosquitoes has fuelled decades of scientific research on mosquito behaviour and control. The search for the perfect topical insect repellent/killer continues. This analysis was conducted to review and explore the scientific information on toxicity produced by the ingredients/contents of a herbal product. In this process of systemic review the following methodology was applied. By doing a MEDLINE search with key words of selected plants, plant based insect repellents/ killers pertinent articles published in journals and authentic books were reviewed. The World Wide Web and the Extension Toxicity Network database (IPCS-ITOX) were also searched for toxicology data and other pertinent information. Repellents do not all share a single mode of action and surprisingly little is known about how repellents act on their target insects. Moreover, different mosquito species may react differently to the same repellent. After analysis of available data and information on the ingredient, of the product in relation to medicinal uses, acute and chronic toxicity of the selected medicinal plants, it can be concluded that the ingredients included in the herbal product can be used as active agents against mosquitoes. If the product which contains the powder of the above said plants is applied with care and safety, it is suitable fo use as a mosquito repellent/killer.