检索结果-南通市图书馆

An Experience on Normothermic Beating Heart Pulmonary Thromboendarterectomy

World Journal of Cardiovascular Surgery 2019年第1期9卷 1-13页

作者： akshay kumar bisoi Pradeep Ramakrishnan Sandeep Chauhan Manoj kumar Sahu Naveen Chander Chandrasekharan Department of CTVS C N Centre All India Institute of Medical Sciences New Delhi India Department of Cardiac Anaesthesiology C N Centre All India Institute of Medical Sciences New Delhi India

Objective: To study the outcome of normothermic beating heart pulmonary thromboendarterectomy (PTE) performed in patients with chronic pulmonary thromboembolism. Methodology: A retrospective analysis of 15 patients who underwent PTE under normothermic beating heart cardio-pulmonary bypass from July 2009 to September 2018 was done. The patients were followed up with clinical assessment, transthoracic echocardiography and computerized tomographicangiography (CTA) for 1 month to 82 months. Results: Data were analysed for 15 consecutive patients. Mean age of the patients was 35.28 years and 10 patients were male. Pre-operatively 6 (40%) patients presented with New York Heart Association (NYHA) class II dyspnoea on exertion symptomatology, 7 (47%) were in NHYA class III, and 2 (13%) were in NYHA class IV. The preoperative and postoperative mean pulmonary artery pressures (mPAP) (mmHg) were 36.50 ± 11.3 and 20.21 ± 7.19, the systolic PAPs (mmHg) were 73.35 ± 14.12 and 35.21 ± 7.89 and the diastolic PAPs (mmHg) were 19.28 ± 8.60 and 12.85 ± 7.26 respectively. 2 (13%) patients had Jamieson’s type I and 12 (87%) had Jamieson type II disease. One patient (7%) expired on 9th postoperative day. All the patients had improved pulmonary gas exchange and did not require oxygen supplementation from 5th postoperative day;symptoms improved to NYHA class I & II in 12 (80%) & 3 (20%) of patients respectively. There was no reperfusion pulmonary edema or any neurologic complications. Postoperative echocardiogram showed improved right ventricular function and Computerised Tomographic Angiogram showed completeness of the procedure. Conclusion: Pulmonary thromboendarterectomy under normothermic beating heart cardiopulmonary bypass has good immediate postoperative results with significant progressive improvement in hemodynamics and quality of life during the course of follow-up. The results were not only comparable to those of the procedure done under deep hypothermic circulatory arrest by ot

关键词： Pulmonary Thromboendarterectomy Normothermic Chronic Thromboembolic Pulmonary Hypertension (CTEPH) Beating Heart

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparison of Parasternal Intercostal Block Using Ropivacaine or bupivacaine for Postoperative Analgesia in Patients Undergoing Cardiac Surgery

引用

World Journal of Cardiovascular Surgery 2015年第6期5卷 49-57页

作者： Kulbhushan Saini Sandeep Chauhan Usha Kiran akshay kumar bisoi Minati Choudhury Suruchi Hasija Department of Cardiothoracic and Vascular Anaesthesia CN Centre All India Institute of Medical Science New Delhi India M.CH Cardiothoracic and Vascular Surgery All India Institute of Medical Science New Delhi India

Objective: The objective of this study was to compare the efficacy of 0.5% ropivacaine and 0.25% bupivacaine for parasternal intercostal block for postoperative analgesia in children undergoing cardiac surgery. Design: A randomized, controlled, prospective, double blind study. Setting: A tertiary care teaching hospital. Participants: One Hundred children scheduled for cardiac surgery through a median sternotomy were divided into 3 groups of at least 33 children each, receiving either ropivacaine, bupivacaine or saline (control). Interventions: A bilateral parasternal block performed either with 0.5% ropivacaine or 0.25% bupiacaine or 0.9% saline with 5 doses of 0.5 mL on each side in the 2nd to 6th parasternal intercostal spaces 1 to 1.5 cm lateral to the sternal edge, before sternal wound closure. Measurements and Main Results: The time to extubation was significantly less in children administered the parasternal blocks with ropivacaine or bupivacaine compared to the saline (control) group. The pain scores were lower and comparable in the ropivacaine and bupivacaine groups compared to the saline group. The cumulative fentanyl dose requirement over a 24-hour period was higher in the saline group than the ropivacaine (p < 0.001) and bupivacaine group. No side effects were observed in any of the children. Conclusions: Parasternal blocks either with ropivacaine or bupivacaine appear to be a simple, safe, and useful technique for supplementation of postoperative analgesia in children undergoing cardiac surgery with a median sternotomy.

关键词： Pediatric Cardiac Patients Parasternal Intercostalblock Sternotomy Ropivacaine Bupivacaine Postoperative Pain

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Reliability assessment of deep excavations in spatially random cohesion weakening friction strengthening massive rocks:Application to nuclear repositories

引用

Underground Space 2023年第6期13卷 48-73页

作者： akshay kumar Gaurav Tiwari Department of Civil Engineering Indian Institute of Technology KanpurKanpurUttar Pradesh 208016India

An augmented methodology is developed to estimate the reliability of deep excavations along spatially variable massive rock masses using the cohesion weakening friction strengthening(CWFS)*** parameters of the CWFS model were initially identified using Sobol’s global sensitivity analysis based on their influence on the displacements and excavation damage zone around *** probability of failure was estimated by performing Mont–Carlo Simulations on random finite difference models of excavations generated via MATLAB-FLAC2D coupling,considering the spatial variation of these sensitive *** variation was modeled by generating anisotropic random fields of sensitive CWFS parameters via the recently developed Fourier series method and updated correlations suggested by Walton(2019).The proposed methodology was demonstrated for a proposed deep nuclear waste repository to be located in *** from the developed methodology were systematically compared with those of traditional reliability(ignoring spatial variation)and deterministic methods(ignoring uncertainty).Although the developed methodology was computationally complex,it was judged to be the most realistic due to the realistic consideration of heterogeneous distributions of rock *** methodologies underestimate/overestimate the excavation performance due to negligence of uncertainty and spatial ***,a parametric analysis was performed using developed methodology by varying the initial friction angle,scale of fluctuations(SOFs)and dilation *** effect of initial friction angle was observed to be more pronounced on the probability of failures as compared to SOFs and dilation *** observations were made related to the excavation damage zone(EDZ)development quantified using yield area ratio.

关键词： Deep excavations Brittle failures CWFS model Sobol’s sensitivity Moving least square response surface Fourier series random field

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Bayesian multi-model inference methodology for imprecise momentindependent global sensitivity analysis of rock structures

引用

Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 840-859页

作者： akshay kumar Gaurav Tiwari Department of Civil Engineering Indian Institute of Technology(IIT)KanpurKanpur208016India

Traditional global sensitivity analysis(GSA)neglects the epistemic uncertainties associated with the probabilistic characteristics(*** of distribution type and its parameters)of input rock properties emanating due to the small size of datasets while mapping the relative importance of properties to the model *** paper proposes an augmented Bayesian multi-model inference(BMMI)coupled with GSA methodology(BMMI-GSA)to address this issue by estimating the imprecision in the momentindependent sensitivity indices of rock structures arising from the small size of input *** methodology employs BMMI to quantify the epistemic uncertainties associated with model type and parameters of input *** estimated uncertainties are propagated in estimating imprecision in moment-independent Borgonovo’s indices by employing a reweighting approach on candidate probabilistic *** proposed methodology is showcased for a rock slope prone to stress-controlled failure in the Himalayan region of *** proposed methodology was superior to the conventional GSA(neglects all epistemic uncertainties)and Bayesian coupled GSA(B-GSA)(neglects model uncertainty)due to its capability to incorporate the uncertainties in both model type and parameters of *** Borgonovo’s indices estimated via proposed methodology provide the confidence intervals of the sensitivity indices instead of their fixed-point estimates,which makes the user more informed in the data collection *** performed with the varying sample sizes suggested that the uncertainties in sensitivity indices reduce significantly with the increasing sample *** accurate importance ranking of properties was only possible via samples of large ***,the impact of the prior knowledge in terms of prior ranges and distributions was significant;hence,any related assumption should be made carefully.

关键词： Bayesian inference Multi-model inference Statistical uncertainty Global sensitivity analysis(GSA) Borgonovo’s indices Limited data

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Jackknife based generalized resampling reliability approach for rock slopes and tunnels stability analyses with limited data:Theory and applications

引用

Journal of Rock Mechanics and Geotechnical Engineering 2022年第3期14卷 714-730页

作者： akshay kumar Gaurav Tiwari Department of Civil Engineering IIT KanpurIndia

An efficient resampling reliability approach was developed to consider the effect of statistical uncertainties in input properties arising due to insufficient data when estimating the reliability of rock slopes and *** approach considers the effect of uncertainties in both distribution parameters(mean and standard deviation)and types of input ***,the approach was generalized to make it capable of analyzing complex problems with explicit/implicit performance functions(PFs),single/multiple PFs,and correlated/non-correlated input *** couples resampling statistical tool,***,with advanced reliability tools like Latin hypercube sampling(LHS),Sobol’s global sensitivity,moving least square-response surface method(MLS-RSM),and Nataf’s *** developed approach was demonstrated for four cases encompassing different *** were compared with a recently developed bootstrap-based resampling reliability *** results show that the approach is accurate and significantly efficient compared with the bootstrap-based *** proposed approach reflects the effect of statistical uncertainties of input properties by estimating distributions/confidence intervals of reliability index/probability of failure(s)instead of their fixed-point ***,sufficiently accurate results were obtained by considering uncertainties in distribution parameters only and ignoring those in distribution types.

关键词： Statistical uncertainty Resampling reliability Moving least square response surface(MLSRSM) Sobol’s global sensitivity Correlation coefficient

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development of a new coated electrode with low nickel content for welding ductile iron and its response to austempering

引用

International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1090-1103页

作者： Tapan Sarkar Ajit kumar Pramanick Tapan kumar Pal akshay kumar Pramanick Welding Technology Centre Jadavpur University Department of Forge Technology NIFFT

Coated Electrodes with small amounts of nickel were developed for welding ductile iron(DI) and conversion of the same into austempered ductile iron(ADI) after austempering. Among six electrodes, Trials 3 and 4 were selected for establishing crack-free weld deposits via preheating and post-weld heat treatment. Austenitization was performed at 900°C for 2 h and austempering at 300 or 350°C for three different holding times to observe the results of austempering with respect to the microstructure, hardness, and austempering kinetics of the samples. The microstructures of the weld deposits showed needle-like bainitic ferrite with small amounts of retained austenite when treated at 300°C and feathery bainitic ferrite with large amounts of retainedaustenite when treated at 350°C. The electrode labeled with Trial 3 revealed greater austenite contents than that labeled with Trial 4 when treated with a 2 h holding time regardless of the austempering temperature applied. The transformation rate of the bainitic ferrite of Trial 3 was relatively higher than that of Trial 4 and showed a lower rate constant, leading to a higher diffusion rate of carbon in austenite.

关键词： electrode development microstructure XRD analysis transformation kinetic microhardness

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Reliability of IEC 61850 based substation communication network architecture considering quality of repairs and common cause failures

引用

Protection and Control of Modern Power Systems 2022年第1期7卷 174-188页

作者： Vonani Clive Mathebula akshay kumar Saha School of Engineering Discipline of ElectricalElectronics and Computer EngineeringUniversity of KwaZulu-NatalDurbanSouth Africa

Mission-critical IEC 61850 system architectures are designed to tolerate hardware failures to achieve the highest reliability ***,multi-channel systems are used in such systems within industrial facilities to isolate machinery when there are process ***,multi-channel systems introduce Common Cause Failure(CCF)since the subsystems can rarely be *** paper integrates CCF into the Markov reliability model to enhance the model flexibility to investigate synchronous generator intra-bay SCN architecture reliability performance considering the quality of repairs and *** Markov process enables integration of the impact of CCF factors on system *** case study results indicate that CCF,coupled with imperfect repairs,significantly reduce system reliability *** sensitivity is observed at low levels of CCF,whereas the highest level of impact occurs when the system diagnostic coverage is 99%based on ISO 13849-1,and reduces as the diagnostic coverage level ***,it is concluded that the severity of CCF depends more on system diagnostic coverage level than the repair efficiency,although both factors impact the system overall ***,CCF should be con-sidered in determining the reliability performance of mission-critical communication networks in power distribution centres.

关键词： IEC 61850 Substation communication network(SCN) Reliability Common cause failure(CCF) Diagnostic coverage Repair efficiency Sensitivity Elasticity Markov Matrix calculus

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fuzzy–frequency ratio model for avalanche susceptibility mapping

引用

International Journal of Digital Earth 2016年第12期9卷 1168-1184页

作者： Satish kumar Snehmani Pankaj kumar Srivastava akshay Gore Mritunjay kumar Singh College of Engineering Studies University of Petroleum&Energy Studies(UPES)DehradunUttarakhandIndia Snow and Avalanche Study Establishment Defence Research&Development Organisation(DRDO)ChandigarhIndia Spatial Strokes Technologies Private Limited ZirakpurPunjabIndia

Avalanche activities in the Indian Himalaya cause the majority of fatalities and responsible for heavy damage to the *** susceptibility maps assist decision-makers and planners to execute suitable measures to reduce the avalanche *** the present study,a probabilistic data-driven geospatial fuzzy–frequency ratio(fuzzy–FR)model is proposed and developed for avalanche susceptibility mapping,especially for the large undocumented *** fuzzy–FR model for avalanche susceptibility mapping is initially developed and applied for Lahaul-Spiti *** fuzzy–FR model utilized the six avalanche occurrence factors(***,aspect,curvature,elevation,terrain roughness and vegetation cover)and one referent avalanche inventory map to generate the avalanche susceptibility *** 292 documented avalanche locations from the avalanche inventory map,233(80%)were used for training the model and remaining 59(20%)were used for validation of the *** avalanche susceptibility map is validated by calculating the area under the receiver operating characteristic curve(ROC-AUC)*** validation of the results using ROC-AUC technique,the success rate and prediction rate were *** values of success rate and prediction rate were 94.07%and 91.76%,*** validation of results using ROC-AUC indicated the fuzzy–FR model is appropriate for avalanche susceptibility mapping.

关键词： Snow avalanche avalanche susceptibility mapping GIS fuzzy–frequency ratio(fuzzy–FR)model Lahaul&Spiti

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Projecting the criticality of COVID-19 transmission in India using GIS and machine learning methods

引用

Journal of Safety Science and Resilience 2021年第2期2卷 50-62页

作者： Farhan Mohammad Khan akshay kumar Harish Puppala Gaurav kumar Rajiv Gupta Department of Civil Engineering BITS PilaniPilaniRajasthanIndia BML Munjal University GurugramIndia

There is a new public health catastrophe forbidding the *** the advent and spread of 2019 novel coro-navirus(2019-nCoV).Learning from the experiences of various countries and the World Health Organization(WHO)guidelines,social distancing,use of sanitizers,thermal screening,quarantining,and provision of lock-down in the cities being the effective measure that can contain the spread of the *** complete lockdown helps in containing the spread,it generates complexity by breaking the economic activity ***,laborers,farmers,and workers may lose their daily *** to these detrimental effects,the government has to open the lockdown *** of the COVID-19 spread and analyzing when the cases would stop increasing helps in developing a *** attempt is made in this paper to predict the time after which the number of new cases stops rising,considering the strong implementation of lockdown conditions using three different techniques such as Decision Tree,Support Vector Machine,and Gaussian Process Regression algorithm are used to project the number of ***,the projections are used in identifying inflection points,which would help in planning the easing of lockdown in a few of the areas *** criticality in a region is evaluated using the criticality index(CI),which is proposed by authors in one of the past of research *** research work is made available in a dashboard to enable the decision-makers to combat the pandemic.

关键词： COVID-19 Machine learning Transmission Lockdown Gaussian process regression Support vector machine Decision tree

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

One Step Synthesis and Growth Mechanism of Carbon Nanotubes

引用

Journal of Materials Science & Technology 2014年第2期30卷 112-116页

作者： akshay kumar K.Singh O.P.Pandey Sri Guru Granth Sahib World University School of Physics and Materials Science Thapar University

A simple one step, reproducible, synthesis route for carbon nanotubes was proposed. No external catalyst was used for the synthesis. These nanotubes were obtained after decomposition of acetone at 650 ℃ in a specially designed autoclave. The pressure generated due to decomposition of acetone played a vital role in the synthesis. The X-ray diffraction pattern and transmission electron microscopy of the sample showed that the diameter of nanotubes is in the range of 3-14 nm. The thermo gravimetric analysis showed 3% weight loss below 500 ℃; the content of amorphous carbon is very less. The growth mechanism of CNTs was also proposed in the present paper.

关键词： Nanostructures Chemical synthesis Electron diffraction Raman spectroscopy Defects

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：