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Search Results: 1 - 10 of 140211 matches for " Anil K. Vashishth "
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Anti-Plane Shear cracks in a Piezoceramic Layer bonded to two half spaces by a New Method
International Journal of Engineering Science and Technology , 2012,
Abstract: In this paper, the anti-plane shear cracks in a piezoceramic layer bonded to similar elastic half spaces is investigated by a new method. The cracks in the mid plane, parallel to the interfaces of the piezoelectric layer are considered. By using the Fourier transform, the problem can be solved with three pairs of integral equations in which the unknown variable is the jump of the displacement across the crack surfaces. These equations are thensolved using Schmidt method. With the help of numerical examples, the result shows that the stress and the electric displacement intensity factors of cracks depend on the geometry of cracks, porosity, thickness of the porous piezoelectric layer.
Reflection and Transmission Phenomena in Poroelastic Plate Sandwiched between Fluid Half Space and Porous Piezoelectric Half Space
Vishakha Gupta,Anil K. Vashishth
Smart Materials Research , 2013, DOI: 10.1155/2013/767019
Abstract: The reflection and transmission of elastic waves in porous piezoelectric plate, overlying a porous piezoelectric half space and underlying a fluid half space, is studied. The constitutive and governing equations are formulated for porous piezoelectric materials. The expressions for the mechanical displacements, electric displacements, stresses, and electric potentials are derived for porous piezoelectric plate, porous piezoelectric half space, and fluid half space. The boundary conditions are described for the studied model. The behaviour of reflected and transmitted amplitude ratios relative to frequency, incident angle, thickness, and porosity is observed numerically. The impedance mismatching problem between the dense piezoelectric materials and the surrounding medium can be solved by the inclusion of porosity in dense piezoceramics. 1. Introduction The field of smart materials (piezoelectric) has advanced rapidly due to an increasing awareness about capabilities of such materials, the development of new materials and transducer designs, and increasingly stringent design and control specifications in aerospace, aeronautics, industrial, automotive, biomedical, and nanosystems. Piezoelectric materials are brittle in nature which leads to the failure of devices. It is commonly found that 5% porosity exists in piezoelectric materials which are considered as manufacturing defects. Instead of considering it as a manufacturing defect, such materials can be modelled as porous piezoelectric materials. Porous piezoelectric materials are widely used in ultrasonic transducers, hydrophones, and pressure sensors. Porous ceramics are of interest for ultrasonic transducer applications. Porosity allows to decrease the acoustic impedance, thus improving transfer of acoustic energy to water or biological tissues. For underwater applications, the figure of merit can also be improved as compared to dense material. The surface impedance of porous piezoelectric materials is less as compared to dense piezoelectric materials. Alvarez-Arenas and De Espinosa [1] made a study related to characterization of porous piezoelectric ceramic. The experimental study on wave propagation in composite structures was done by Alvarez-Arenas et al. [2]. Different authors [3, 4] developed models related to synthesis, fabrication, and processing of porous piezoelectric materials. Kumar et al. [5] investigated the effects of porosity and pore forming agents in porous piezoceramics. The influence of piezoelectricity on the reflection-transmission phenomena in fluid-loaded piezoelectric half
Effectiveness of Bumetanide Infusion in Treatment of Generalized Edema and Congestive Heart Failure  [PDF]
Anil K. Mandal
Open Journal of Internal Medicine (OJIM) , 2014, DOI: 10.4236/ojim.2014.43012
Abstract: Generalized edema (anasarca) is common in nephrotic syndrome which rarely produces shortness of breath. Increased shortness of breath associated with rapid weight gain and generalized edema signify congestive heart failure (CHF). Loop diuretics consisting of furosemide (Lasix®), bumetanide (Bumex®), torsemide (Demadex®) or ethacrynic acid (Edecrin) are effective diuretics to treat anasarca. However, efficacy varies depending on the renal function. Loop diuretic given orally or by intravenous boluses produce good urine output but overall response in reducing edema or shortness of breath as in CHF is less than optimum. Although literature information is very limited, continuous bumetanide infusion for 72 to 96 hours is found to be very effective in producing subjective relief of shortness of breath as well as objective improvement such as reduction in brain natriuretic peptide in CHF and improved kidney function, so that diuresis is sustained even after discontinuation of the infusion. Decrease in kidney function and electrolytes and acid-base imbalance are common but they are reversible with prompt replacement therapy. They pose no threat to life.
Pathogenesis and Prevention of Progression of Chronic Kidney Disease  [PDF]
Anil K. Mandal
Open Journal of Internal Medicine (OJIM) , 2015, DOI: 10.4236/ojim.2015.53010
Abstract: This treatise of chronic kidney disease (CKD) describes association of hypertension, diabetes and congestive heart failure (CHF) with CKD. CKD is defined by estimated glomerular filtration rate (eGFR) of less than 60 ml/min for three months or more. CKD is generally irreversible but not necessarily progressive. Thus progression of CKD into end stage renal disease (ESRD) is the concern here and what can be done to reduce the progression of CKD. Exact data of CKD with progression are unavailable but high incidence of ESRD (dialysis) eleven times more in 2011 than in 1980 accordingly to United States (US) Renal Data System is a testimonial to progression of CKD in patients with diabetes, hypertension, CHF and other renal diseases. US Renal Data System reveals that ESRD has soared in parallel with marketing of angiotensin converting enzyme inhibitor (ACEI) and angiotensin receptor blocker (ARB) drugs, providing strong indirect evidence that these drugs are someway instrumental in the progression of CKD into ESRD. These drugs produce acute renal failure which is an independent risk factor for CKD. Thus shift in therapy with enthusiastic use of ACEI/ARB drugs has led to dialysis bonanza throughout the world benefiting the professionals and corporations at the expense of vegetative life of the patients associated with family and societal burdens. The ways to turn the pendulum is to treat diabetes with insulin and hypertension with beta blocker, calcium channel blocker and diuretic therapy, and avoid the use of ACEI/ARB drugs. It is important to understand that diuretic orally, by intravenous boluses or by continuous infusion, is the cornerstone of therapy for CHF, whereas ACEI/ARB drugs markedly impair the efficacy of diuretics by lowering the blood pressure to a very low level thereby reducing renal perfusion. An evidence for that is marked elevation of BUN with comparatively slight increase of serum creatinine. Thus with the approaches stated above, CKD is less likely to progress; hence rate of ESRD is likely to decrease.
Designing and Modeling of Efficient Resonant Photo Acoustic Sensors for Spectroscopic Applications  [PDF]
Fahem Yehya, Anil K. Chaudhary
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24028
Abstract: We report the modeling and designing aspects of different types of photo-acoustic (PA) cell based on the excitation of longitudinal, radial and azimuthal mode using CW and pulse lasers. The results are obtained by employing fluid dynamics equations along with Bessel’s function. The obtained results based on stimulation of longitudinal, radial and azimuthally resonance modes of the Photo acoustic signals in the suitable cavity. This is utilized to design highly efficient low volume PA detector for the spectroscopic studies of different types of atmospheric pollutants. We have also studied the dependence of the excited photo acoustic signals on various parameters such as cell radius, laser power, absorption coefficient, quality factor ‘Q’ along with the first longitudinal, radial, azimuthal mode and the pressure. The simulated results show the linearity of the PA signal with different concentration of the gas sample.
Heterogeneous Glycation of Cancellous Bone and Its Association with Bone Quality and Fragility
Lamya Karim, Deepak Vashishth
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035047
Abstract: Non-enzymatic glycation (NEG) and enzymatic biochemical processes create crosslinks that modify the extracellular matrix (ECM) and affect the turnover of bone tissue. Because NEG affects turnover and turnover at the local level affects microarchitecture and formation and removal of microdamage, we hypothesized that NEG in cancellous bone is heterogeneous and accounts partly for the contribution of microarchitecture and microdamage on bone fragility. Human trabecular bone cores from 23 donors were subjected to compression tests. Mechanically tested cores as well as an additional 19 cores were stained with lead-uranyl acetate and imaged to determine microarchitecture and measure microdamage. Post-yield mechanical properties were measured and damaged trabeculae were extracted from a subset of specimens and characterized for the morphology of induced microdamage. Tested specimens and extracted trabeculae were quantified for enzymatic and non-enzymatic crosslink content using a colorimetric assay and Ultra-high Performance Liquid Chromatography (UPLC). Results show that an increase in enzymatic crosslinks was beneficial for bone where they were associated with increased toughness and decreased microdamage. Conversely, bone with increased NEG required less strain to reach failure and were less tough. NEG heterogeneously modified trabecular microarchitecture where high amounts of NEG crosslinks were found in trabecular rods and with the mechanically deleterious form of microdamage (linear microcracks). The extent of NEG in tibial cancellous bone was the dominant predictor of bone fragility and was associated with changes in microarchitecture and microdamage.
Stem Reserve Mobilization and Sink Activity in Wheat under Drought Conditions  [PDF]
Anil K. Gupta, Kamaljit Kaur, Narinder Kaur
American Journal of Plant Sciences (AJPS) , 2011, DOI: 10.4236/ajps.2011.21010
Abstract: The effect of water deficit on stem reserve mobilization and sink activity in wheat (Triticum aestivum L.) cultivars, viz., C306 (drought tolerant) and PBW343 (drought sensitive) was studied. Drought was maintained in pot raised plants by withholding irrigation at 95 days after sowing (DAS), i.e. just five days before the initiation of anthesis. Drought induced a significant reduction in mean biomass of all the internodes of sensitive cultivar as compared to those of tolerant one. Mobilized dry matter and mobilization efficiency were observed to be higher in the internodes of tolerant cultivar, both under control and stress conditions, which resulted in enhanced translocation of stem reserves to the grains. Water soluble carbohydrates (WSC), which mainly occur as fructans, were observed to be higher in the internodes of tolerant cultivar than those of sensitive one. When drought was applied, fructans were mobilized more effectively from the internodes of tolerant cultivar. A significantly higher sucrose synthase activity in the grains of tolerant cultivar, under drought conditions, increased the sink strength by unloading the assimilates in the sink, thereby increasing further mobilization of assimilates to the grains. Grains of sensitive cultivar attained maturity much earlier as compared to the tolerant one, both under control and stress conditions. The longer duration of grain maturation in tolerant cultivar supported enhanced mobilization of stem reserves, thus restricting heavy decrease in grain yield, under stress conditions, as compared to the sensitive cultivar. It may, therefore, be concluded that certain characteristics viz., enhanced capability of fructan storage, higher mobilization efficiency, stronger sink activity and longer duration of grain maturation might help the drought tolerant cultivar in coping the stress conditions
Testing Component-Based Software: What It has to do with Design and Component Selection  [PDF]
Shyam S. Pandeya, Anil K. Tripathi
Journal of Software Engineering and Applications (JSEA) , 2011, DOI: 10.4236/jsea.2011.41005
Abstract: In a component-based software development life cycle, selection of preexisting components is an important task. Every component that has to be reused has an associated risk of failure of not meeting the functional and non-functional requirements. A component's failure would lead a developer to look for some other alternative of combinations of COTS, in-house and engineered components among possible candidate combinations. This means design itself can readily change. The very process of design of a software system and component selection seems to be heavily dependent on testing results. Instability of design, further, becomes more severe due to requirements change requests. Therefore, this instability of design has to be essentially mitigated by using proper design and testing approaches, otherwise, it may lead to exorbitantly high testing cost due to the repeated testing of various alternatives. How these three activities: Component-based software design, component selection and component-based software testing are interrelated? What process model is most suited to address this concern? This work explores the above questions and their implication in terms of nature of a process model that can be convincing in case of component-based software development.
A Predicted Region based Cache Replacement Policy for Location Dependent Data in Mobile Environment  [PDF]
Ajey KUMAR, Manoj MISRA, Anil K. SARJE
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.11012
Abstract: Caching frequently accessed data items on the mobile client is an effective technique to improve the system performance in mobile environment. Proper choice of cache replacement technique to find a suitable subset of items for eviction from cache is very important because of limited cache size. Available policies do not take into account the movement patterns of the client. In this paper, we propose a new cache replacement policy for location dependent data in mobile environment. The proposed policy uses a predicted region based cost function to select an item for eviction from cache. The policy selects the predicted region based on client’s movement and uses it to calculate the data distance of an item. This makes the policy adaptive to client’s movement pattern unlike earlier policies that consider the directional / non-directional data distance only. We call our policy the Prioritized Predicted Region based Cache Replacement Policy (PPRRP). Simulation results show that the proposed policy significantly improves the system performance in comparison to previous schemes in terms of cache hit ratio.
Training Programmes for Distance Education Professionals: An Analytical Assessment
The Turkish Online Journal of Distance Education , 2006,
Abstract: Present paper seeks to analyze the impact of training programmes on distance education professionals of Indira Gandhi National Open University, (IGNOU). The objective of the paper is to identify the training needs of Distance Education Professionals to manage distance education affairs of IGNOU, to evaluate the effectiveness of existing training programmes, to develop a feasible training and professional development model for distance education Professionals (DEPs) and to suggest initiatives in existing training for the skill development of DEPs for effective career growth and development. Attempt has been made to apply statistical tools such as skewness, kurtosis, regression and correlation on a different set of variables to assess the impact of the training programmes on DE professionals such as teachers and academics. While addressing the objectives of the study it is revealed that some of the indicators have opened up scope for improvement. Nevertheless trainees have expressed mixed reaction on the quality of training pgrammes with respect to content, methodology and effectiveness. Based on the analysis a workable training model has also been suggested where emphasis on the Common Training Approach (CTA) has been given besides, work specific training. For the over all professional development of DEPs a suitable training strategy has been worked out which ensures training at different strata that includes primary, secondary & tertiary level considering the experience & job requirements of the professionals.
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