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Modal analysis of prestressed draft pad of freight wagons using finite element method

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Journal of Modern Transportation 2015年第1期23卷 43-49页

作者： Sachin Sudhakar Harak Satish Chand Sharma Suraj Prakash harsha Vibration and Noise Control Lab. Mechanical and Industrial Engineering Department Indian Institute of Technology

The present work intends to investigate dynamic behaviour of draft gear using finite element method. The longitudinal force that the draft gear absorbs usually leads to the failure of its components, especially, the load bearing draft pads. Dynamic behaviour of an individual draft pad and a draft gear is determined and characterized with exciting frequen- cies and corresponding mode shapes. The effect of compressive prestress load on the dynamic behaviour of an individual draft pad is also determined as the draft pads in assembled state are under constant axial compressive force in the draft gear. The vibration characteristics of individual draft pad are compared with draft pads that are part of draft gear. The modal analysis gives us a basis for subjecting a draft pad to higher frequency loading for determining its fatigue behaviour.

关键词： Draft gear. Draft pad. Prestress Naturalfrequency Mode shapes Finite element method

Risk of New-Onset Atrial Fibrillation in Elderly Patients with the Overlap Syndrome: A Retrospective Cohort Study

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Journal of Geriatric Cardiology 2013年第2期10卷 129-134页

作者： harsha V. Ganga Sanjeev U. Nair Venkata K. Puppala Wayne L. Miller The Henry Low Heart Center Hartford Hospital B-1010 80 Seymour Street Hartford CT 06102 USA St. Joseph's Hospital 45 W 10th St St. Paul MN 55102 USA Division of Cardiovascular Diseases Mayo Clinic Rochester MN 55905 USA

Background Co-existence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) is referred to as overlap syndrome. Overlap patients have greater degree of hypoxia and pulmonary hypertension than patients with OSA or COPD alone. Studies showed that elderly patients with OSA alone do not have increased risk of atrial fibrillation (AF) but it is not known if overlap patients have higher risk of AF. Objective To determine whether elderly patients with overlap syndrome have an increased risk of AF. Methods In this single center, community-based retrospective cohort analysis, data were collected on 2,873 patients > 65 years of age without AF, presenting in the year 2006. Patients were divided into OSA group (n = 60), COPD group (n = 416), overlap syndrome group (n = 28) and group with no OSA or COPD(n = 2369). The primary endpoint was incidence of new-onset AF over the following two years. Logistic regression was performed to adjust for heart failure (HF), coronary artery disease, hypertension (HTN), cerebrovascular disease, cardiac valve disorders, diabetes mellitus, hyperlipidemia, chronic kidney disease (CKD) and obesity. Results The incidence of AF was 10% in COPD group, 6% in OSA group and 21% in overlap syndrome group (P < 0.05). After adjusting for age, sex, HF, CKD, and HTN, patientswith overlap syndrome demonstrated a significant association with new-onset AF (OR = 3.66, P = 0.007). HF, CKD and HTNwere also significantly associated with new-onset AF (P < 0.05). Conclusion Among elderly patients, the presence of overlap syndrome is associatedwith a marked increase in risk of new-onset AF as compared to the presence of OSA or COPDalone.

关键词： Atrial arrhythmias Elderly patients Obstructive lung disease Sleep apnea

Effect of Center Voltage Vectors(CVVs)of Three-level Space Plane on the Performance of Dual Inverter Fed Open End Winding Induction Motor Drive

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Chinese Journal of Electrical Engineering 2019年第2期5卷 43-55页

作者： M.harsha Vardhan Reddy K.Sri Gowri T.Bramhananda Reddy G.Kishor Department of EEE G.Pulla Reddy Engineering CollegeKurnoolAPIndia

Dual inverter fed open end winding induction motor(IM)drive offers many advantages over other multilevel inverter fed IM *** width modulation(PWM)techniques are employed for the control of output voltage and *** vector base PWM techniques are popular among all the PWM techniques.A simplified space vector PWM method with simple and small look-up table approach is presented for dual inverter *** the proposed space vector based PWM technique provides freedom in selecting the center voltage vector(CVV)by which different PWM techniques will be *** implementation of all these PWM techniques is generalized by using a constant *** derived PWM techniques show superior performance in reducing the zero sequence voltage(ZSV)by maintaining the same quality of output *** performance of all these PWM techniques are evaluated theoretically and verified in real time through dSPACE 1104 control board.

关键词： Center voltage vectors coupled PWM decoupled PWM space vector PWM zero sequence voltage

A hybrid BFA-PSO algorithm for economic dispatch with valve-point effects

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Frontiers in Energy 2012年第2期6卷 155-163页

作者： T.JAYABARATHI Prateek BAHL harsha OHRI Afshin YAZDANI V. RAMESH School of Electrical Engineering V I T University Vellore 632014India

This paper presents a novel and efficient method for solving the economic dispatch （ED） problems with valve-point effects, by integrating the biased velocity of particle swarm optimization （PSO） to the chemotaxis, swarming and reproduction steps of bacterial foraging algorithm （BFA）. To include valve point effects sinusoidal terms are added to the fuel cost function. This makes the ED problems highly non-linear. In order to solve such problems the best cell （or particle） biased velocity （vector） is added to the random velocity of the BFA to reduce randomness in movement （evolution） and to increase swarming. This results in the hybrid bacterial foraging algorithm （HBFA）. To demonstrate the effectiveness of the proposed HBFA method, numerical studies have been performed for three different sample systems. Comparison of the results obtained by the HBFA with the BFA and other evolutionary algorithms clearly show that the proposed method outperforms other methods in terms of convergence rate and solution quality in solving the ED problems with valve-point effects.

关键词： bacterial foraging algorithm (BFA) economic dispatch (ED) particle swarm optimization (PSO) valve- point effects

Whole-body heat exposure induces membrane changes in spermatozoa from the cauda epididymidis of laboratory mice

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Asian Journal of Andrology 2010年第4期12卷 591-598页

作者： harsha Wechalekar Brian P. Setchell Eleanor J. Peirce Mario Ricci Chris Leigh William G. Breed Discipline of Anatomy and Pathology School of Medical Sciences Faculty of Health Sciences University of Adelaide Adelaide South Australia 5005 Australia Division of Health Sciences University of South Australia City East Campus Adelaide South Australia 5000 Australia

This study was carried out to determine if exposure to hot environmental temperatures had a direct, detrimental effect on sperm quality. For this the effect of whole-body heat exposure on epididymal spermatozoa of laboratory mice was investigated. C57BL/6 mice （n = 7） were housed in a microclimate chamber at 37℃-38℃ for 8 h per day for three consecutive days, while control mice （n = 7） were kept at 23℃-24℃. Cauda epididymal spermatozoa were obtained 16 h after the last heat treatment. The results showed that sperm numbers were similar in the two groups （P = 0.23）, but after heat treatment, a significant reduction in the percentage of motile sperm was present （P 〈 0.0001）. Membrane changes of the spermatozoa were investigated by staining with phycoerythrin （PE）- conjugated Annexin V, which detects exteriorization of phosphotidylserine from the inner to the outer leaflet of the sperm plasma membrane, and 7-aminoactinomycin D （7-AAD）, which binds to the sperm nucleus when the plasma membrane is damaged. The percentage of spermatozoa showing positive staining with Annexin V-PE or 7-AAD or both, was significantly higher （P 〈 0.05） in heat-exposed mice compared with controls. These results show that whole-body heat exposure to 37℃-38℃ induces membrane changes in the epididymal spermatozoa of mice, which may lead to apoptosis.

关键词： laboratory mice sperm membrane damage whole-body heat

The impact of dysfunctional tear films and optical aberrations on chronic migraine

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Eye and Vision 2017年第1期4卷 18-21页

作者： Rohit Shetty Kalyani Deshpande Chaitra Jayadev Kareeshma Wadia Pooja Mehta Rushad Shroff harsha L.Rao Department of Ophthalmology Narayana Nethralaya Eye Institute121/CChord Road1“R”BlockRajajinagarBangalore 560010KarnatakaIndia

Background:Migraine is a multifactorial disorder with complex neuronal and vascular mechanisms that encompasses a wide clinical spectrum of symptoms,including ocular *** eye disease and dysfunction of ocular somatosensory pathways have been implicated in the *** current study investigates the association between a dysfunctional tear film and ocular aberrations with ***:Sixty eyes of 30 patients with migraine and 60 eyes of 30 controls were *** eye evaluation included Schirmer’s test,tear film break-up time,corneal esthesiometry and lipid layer analysis using Lipiview^(®)*** aberrations were measured using Optical Path Difference before performing the dry eye *** intraocular light scatter was quantified using the objective scatter index(OSI)of the optical quality analysis *** parameters were compared between the migraine and the control group using independent sample *** analysis was performed using commercial software.A p value of≤0.05 was considered statistically ***:There were 19 females and 11 males in each *** significant difference was found between the two groups with respect to total aberrations(p=0.049),higher order aberrations(p=0.009),coma(p=0.03),spherical aberrations(p=0.018),Lipiview interferometric coloric units(p<0.001)and OSI(p<0.001).Trefoil(p=0.26)and TBUT(p=0.398)were not significantly different between both ***:Ocular aberrations are higher in patients with migraine as compared with *** film abnormalities add to the aberrations in otherwise asymptomatic patients and may also be associated with migraineous *** the ocular surface to obtain a healthy tear film might introduce a potential modifiable factor in the prevention of migraneous attacks.

关键词： Migraine Dry eye Aberrations

Bi-Directional Giant Magneto Impedance Sensor

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Advances in Materials Physics and Chemistry 2013年第5期3卷 249-254页

作者： harsha Uppili Bevin Daglen Oregon Episcopal School High School Portland USA

A thin film giant magneto impedance (GMI) based on magnetic field sensor has been developed using electrodeposited Ni-Fe permalloy. Chemical composition, surface morphology, and magnetic properties of Ni-Fe permalloy were char-acterized as a function of plateup parameters, and process conditions were established to deposit a Ni-Fe thin film with a high permeability (~1000) and a low coercivity (0.6 Oersted). Conventional GMI sensors are uni-directional and are several millimeters long. In this work, a spiral-shaped sensor using electroplated Ni-Fe permalloy to detect bi-directional magnetic field is reported. Excellent bi-directional magnetic field sensing has been demonstrated using the 1 mm2 compact double-spiral structure.

关键词： Giant Magneto Impedance Bi-Directional Sensor Permalloy

In vitro antioxidant activity and in vivo hepatoprotective activity of aqueous extract of Allium cepa bulb in ethanol induced liver damage in Wistar rats

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Food Science and Human Wellness 2013年第3期2卷 132-138页

作者： K.Eswar Kumar K.N.harsha V.Sudheer Nelli Giri babu Pharmacology Division A.U.College of Pharmaceutical SciencesAndhra UniversityVisakhapatnam 530003Andhra PradeshIndia

The in vitro antioxidant and in vivo hepatoprotective effects of aqueous extract of Allium cepa(***)bulb were evaluated in male rats against ethanol induced liver damage in preventive and curative *** antioxidant activity of *** was assayed and activities were compared to standard antioxidant,ascorbic *** results revealed that the IC50 values of *** bulb extract for DPPH,hydroxyl,superoxide radical scavenging activities were 195.2±0.2,374.7±0.4 and 182.5±1.7g/mL,*** injury was induced by 40%ethanol administration(3.76 g/kg bw,orally)for 25 *** two different sets of experiments,the *** extracts(100,300 and 600 mg/kg bw)and silymarin(100 mg/kg bw)were administered orally in preventive and curative *** administration caused severe hepatic damage in rats as evidenced by elevated serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),alkaline phosphatase(ALP)and total bilirubin *** *** and silymarin administration prevented the toxic effect of ethanol on the above serum parameters in both preventive and curative *** present study concludes that aqueous extract of *** bulb has significant antioxidant and hepatoprotective activity against ethanol induced hepatotoxicity.©2013 Beijing Academy of Food *** and hosting by Elsevier *** rights reserved.

关键词： Allium cepa Antioxidant Ethanol Hepatoprotective Rat

Use of thyroglobulin as a tumour marker

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World Journal of Biological Chemistry 2017年第1期8卷 81-85页

作者： Buddhike Sri harsha Indrasena Consultant General and Endocrine Surgeon Kandy General Hospital(Teaching)Kandy 20000Sri Lanka

It is worthwhile to measure serum thyroglobulin(TG) level in thyroid cancer before subjecting patients to surgery for two reasons. Firstly, if the level is high, it may give a clue to the local and metastatic tumour burden at presentation; secondly, if the level is normal,it identifies the patients who are unlikely to show rising TG levels in the presence of thyroid cancer. Those who have high serum TG before surgery will show up recurrence as rising serum TG during the postoperative period. Those who do not have high serum TG before surgery will not show up rising serum TG in the presence of recurrent disease. In the latter situation, normal TG level gives only a false reassurance regarding recurrence of disease. Nevertheless, rising serum TG during the postoperative period must be interpreted cautiously because this could be due to the enlargement of noncancerous residual thyroid tissue inadvertently left behind during surgery.

关键词： Thyroglobulin Thyroid cancer Recurrent thyroid cancer Anti-thyroglobulin antibodies Tumour marker