检索结果-南通市图书馆

Study of damage behavior and repair effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading

引用

Defence Technology（防务技术） 2024年第4期34卷 29-41页

作者： alok Kumar Chinmaya Kumar Sahoo A.Arockiarajan Department of Applied Mechanics Indian Institute of Technology MadrasChennai 600036India

Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural *** work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair *** evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]*** Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection *** laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged *** different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI *** results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine *** of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine ***,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.

关键词： Carbon fiber reinforced polymers(CFRP) Quasi-isotropic laminate Quasi static indentation(QSI) Acoustic emission(AE) Composite repair

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

An improved reverse time migration for subsurface imaging over complex geological structures:A numerical study

Energy Geoscience

引用

Energy Geoscience 2024年第2期5卷 290-297页

作者： alok Kumar Routa Priya Ranjan Monahty Department of Applied Geophysics IIT(ISM)DhanbadJharkhandIndia

In seismic exploration,it is a critical task to image and interpret different seismic signatures over complex geology due to strong lateral velocity contrast,steep reflectors,overburden strata and dipping *** understand the behavior of these seismic signatures,nowadays Reverse Time Migration(RTM)technique is used extensively by the oil&gas *** the extrapolation phase of RTM,the source wavefield needs to be saved,which needs high storage memory and large computing *** two are the main obstacles of RTM for production *** order to overcome these disadvantages,in this study,a second-generation improved RTM technique is *** this improved form,a shift operator is introduced at the time of imaging condition of RTM algorithm which is performed automatically both in space and time *** effort is made to produce a better-quality image by minimizing the computational time as well as numerical *** proposed method is applied over various benchmark models and validated by implementing over one field data set from the Jaisalmer Basin,*** the analysis,it is observed that the method consumes a minimum of 45%less storage space and reduce the execution time by 20%,as compared to conventional *** proposed RTM is found to work efficiently in comparison to the conventional RTM both in terms of imaging quality and minimization of numerical artefacts for all the benchmark models as well as field data.

关键词： Imaging condition Reverse time migration(RTM) Seismic imaging Velocity-depth model Wave propagation

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

Characterization and Propagation of Historical and Projected Droughts in the Umatilla River Basin, Oregon, USA

引用

Advances in Atmospheric Sciences 2024年第2期41卷 247-262,I0020-I0028页

作者： Sudip GAUTAM alok SAMANTARAY Meghna BABBAR-SEBENS Meenu RAMADAS School of Civil and Construction Engineering Oregon State UniversityCorvallisOR 97331USA School of Infrastructure Indian Institute of TechnologyBhubaneswarOdisha 752050India

Climate change is expected to have long-term impacts on drought and wildfire risks in Oregon as summers continue to become warmer and drier. This paper investigates the projected changes in drought characteristics and drought propagation in the Umatilla River Basin in northeastern Oregon for mid-century(2030–2059) and late-century(2070–2099) climate scenarios. Drought characteristics for projected climates were determined using downscaled CMIP5 climate datasets from ten climate models and Soil and Water Assessment Tool to simulate effects on hydrologic processes. Short-term(three months) drought characteristics(frequency, duration, and severity) were analyzed using four drought indices, including the Standardized Precipitation Index(SPI-3), Standardized Precipitation-Evapotranspiration Index(SPEI-3), Standardized Streamflow Index(SSI-3), and the Standardized Soil Moisture Index(SSMI-3). Results indicate that short-term meteorological droughts are projected to become more prevalent, with up to a 20% increase in the frequency of SPI-3drought events. Short-term hydrological droughts are projected to become more frequent(average increase of 11% in frequency of SSI-3 drought events), more severe, and longer in duration(average increase of 8% for short-term droughts).Similarly, short-term agricultural droughts are projected to become more frequent(average increase of 28% in frequency of SSMI-3 drought events) but slightly shorter in duration(average decrease of 4%) in the future. Historically, drought propagation time from meteorological to hydrological drought is shorter than from meteorological to agricultural drought in most sub-basins. For the projected climate scenarios, the decrease in drought propagation time will likely stress the timing and capacity of water supply in the basin for irrigation and other uses.

关键词： Umatilla drought SPI SPEI SSI SSMI

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

Determinants of infant mortality in rural India: A three-level model

引用

Health 2013年第11期5卷 1742-1749页

作者： Sada Nand dwivedi Shahina Begum alok Kumar dwivedi Arvind Pandey Department of Biostatistics All India Institute of Medical Sciences (AIIMS) New Delhi India Department of Biostatistics All India Institute of Medical Sciences (AIIMS) New Delhi India National Institute of Medical Statistics Indian Council of Medical Research New Delhi India

Taking into account the hierarchical structure of the data, through two-level analysis on infant mortality available under second round of National family Health Survey, the same group of authors recently reported determinants of infant mortality while examining possible changes in results under traditional regression analysis that ignores hierarchical structure of data. They reported that the community (e.g., state) level characteristics still have a major role regarding infant mortality in India. For better epidemiological understanding, the present study is to assess determinants of infant mortality in rural India, where three level considerations were possible. The results indicate that even after consideration of these covariates, variation in infant mortality remains significant not only between States but also between Districts. Further, as an additional observation, the probability of infant mortality is still high in rural areas of districts having health facility beyond three kilometers than their counterparts.

关键词： Infant Mortality Hierarchical Structure National Family Health Survey State Level District Level Public Health Multilevel Logistic Regression Traditional Logistic Regression

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

Statistical models for predicting number of involved nodes in breast cancer patients

引用

Health 2010年第7期2卷 641-651页

作者： alok Kumar dwivedi Sada Nand dwivedi Suryanarayana Deo Rakesh Shukla Center for Biostatistical Services Department of Environmental Health College of Medicine University of Cincinnati Cincinnati USA.

Clinicians need to predict the number of involved nodes in breast cancer patients in order to ascertain severity, prognosis, and design subsequent treatment. The distribution of involved nodes often displays over-dispersion—a larger variability than expected. Until now, the negative binomial model has been used to describe this distribution assuming that over-dispersion is only due to unobserved heterogeneity. The distribution of involved nodes contains a large proportion of excess zeros (negative nodes), which can lead to over-dispersion. In this situation, alternative models may better account for over-dispersion due to excess zeros. This study examines data from 1152 patients who underwent axillary dissections in a tertiary hospital in India during January 1993-January 2005. We fit and compare various count models to test model abilities to predict the number of involved nodes. We also argue for using zero inflated models in such populations where all the excess zeros come from those who have at some risk of the outcome of interest. The negative binomial regression model fits the data better than the Poisson, zero hurdle/inflated Poisson regression models. However, zero hurdle/inflated negative binomial regression models predicted the number of involved nodes much more accurately than the negative binomial model. This suggests that the number of involved nodes displays excess variability not only due to unobserved heterogeneity but also due to excess negative nodes in the data set. In this analysis, only skin changes and primary site were associated with negative nodes whereas parity, skin changes, primary site and size of tumor were associated with a greater number of involved nodes. In case of near equal performances, the zero inflated negative binomial model should be preferred over the hurdle model in describing the nodal frequency because it provides an estimate of negative nodes that are at “high-risk” of nodal involvement.

关键词： Nodal Involvement Count Models Breast Cancer

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

An epidemiological study on delay in treatment initiation of cancer patients

引用

Health 2012年第2期4卷 66-79页

作者： alok Kumar dwivedi Sada Nand dwivedi Suryanarayana Deo Rakesh Shukla Arvind Pandey Durgesh Kumar dwivedi Center for Biostatistical Services Division of Biostatistics and Epidemiology Department of Environmental Health College of Medicine University of Cincinnati Cincinnati USA Department of Biostatistics All India Institute of Medical Sciences New Delhi India Department of NMR & MRI Facility All India Institute of Medical Sciences New Delhi India Department of Surgical Oncology All India Institute of Medical Sciences New Delhi India National Institute of Medical Statistics Indian Council of Medical Research New Delhi India

Early diagnosis and timely initiation of treatment of cancer patients may improve survival and quality of life. Various measures of delay can be made during diagnosis and treatment initiation. Most of the studies were based on single type of cancer with different definitions and measurements of delay in diagnosis and treatment. Thus, it has been difficult to synthesize results and generalize to other types of cancer. The study proposes to measure total duration between onsets of symptom to start of treatment into three components, namely primary, secondary and tertiary delays. Primary delay is defined as onset of symptoms to contacting the first medical person, secondary delay is from first medical contact to confirmed diagnosis, and tertiary delay is from confirmed diagnosis to treatment initiation. The aim of this study is to determine factors associated with primary, secondary and tertiary delays in cancer patients. This study was planned as a cross-sectional study. Data was collected from patients admitted to the surgical wards of Department of Surgical Oncology, Institute Rotary Cancer Hospital, New Delhi during 2006-2007. Gamma regression and quantile regressions at 25th, 50th and 75th percentile of each of the delays were used to determine related factors. A total of 403 patients were included in the analysis. The median tertiary delay was found almost two folds (59;Interquartile range: 26 - 101 days) than the primary and secondary delays. Extremity cancer patients had longest primary, secondary and tertiary delays. Shortest primary, secondary and tertiary delays were observed for gastrointestinal cancer, breast and genitourinary cancer respectively. There is an urgent need and scope to reduce delay at each level primary, secondary and tertiary delay. Intervention studies are needed through information, education and communication/screening programs to reduce the diagnostic and treatment delays in cancer patients.

关键词： Delay Cancer Log Gamma Regression Quantile Regression

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

Association of Obesity in Children with Pancreatitis in a Predominantly Hispanic Population at the US-Mexican Border: A Single Center Outpatient Study

引用

Health 2016年第15期8卷 1820-1829页

作者： Indu Pathak Diana Malbas Pukhraj Rai alok Kumar dwivedi Department of Pediatrics Paul L. Foster School of Medicine Texas Tech University Health Sciences Center El Paso Texas USA El Paso Children’s Hospital El Paso Texas USA Division of Biostatistics & Epidemiology Department of Biomedical Sciences Paul L. Foster School of Medicine Texas Tech Univer-sity Health Sciences Center El Paso Texas USA

Importance: The incidence of pancreatitis has been increasing over the last decade. Limited data are available for pancreatitis in the Hispanic population. The clinical profile of pancreatitis and its association with obesity in a Mexican American population has not been well studied. Objective: To describe prevalence, the characteristics of pancreatitis cases, and determine its association with obesity. Design and Setting: Retrospective review of children from February 2012 to February 2015, at the Texas Tech University Health Sciences Center of El Paso (TTUHSC-El Paso) outpatient center. Case/non-case study was used to determine the association of overweight and obesity with pancreatitis. Participants: Children ages 2 - 18 years, only the newly diagnosed pancreatitis cases irrespective of its type excluding patients with traumatic and repeat visit for pancreatitis. Main Outcome and Measures: Pancreatitis and obesity. Results: The prevalence of pancreatitis was estimated as 20 cases in 21,444 patients seen in the outpatient clinic. In multivariable analysis, only obesity and ethnicity were significantly associated with pancreatitis. Obesity was found to be more than 7-fold likely with pancreatitis as compared to non-cases. Overweight was found to be more than 6-fold likely with pancreatitis as compared with non-cases. Our study demonstrates an association between obesity and pancreatitis in the study population. Conclusions and Relevance: Appropriate intervention for managing obesity may reduce the prevalence of pancreatitis and associated co-morbidities. A larger prospective study should be done to determine underlying causes of association between obesity and pancreatitis.

关键词： Pancreatitis Obesity Body Mass Index (BMI)

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

Insight into Metabolomic Profiling of Tinospora cordifolia: Recent Advances and Future Perspectives of Quality Control

引用

World Journal of Traditional Chinese Medicine 2024年第2期10卷 137-148页

作者： Atiqul Islam C.Anurag Nazia Siddiqui Xianting Ding alok Sharma College of Pharmacy JSS Academy of Technical EducationNoidaUttar PradeshIndia Department of Pharmaceutical Technology MIETMeerutUttar PradeshIndia Institute for Personalized Medicine School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghaiChina

The objective of this study was to offer a review of previous works on Tinospora cordifolia(TC) metabolomics with a highlight on the use of metabolomics in comparative evaluations between varieties and selection of optimum cultivation, collection, and extraction procedures, providing insights into pharmaceutical and food product quality monitoring. Scholarly databases were searched to gather relevant information on TC's therapeutic usefulness, phytoconstituent studies, metabolomics, and applications. Pub Chem was used to learn the structures of several of the metabolites. The various medicinal properties of TC were extensively researched. The most essential portions of the plant in Ayurvedic medicines are the stems. Bioactive phytochemicals such as steroidal lactones, alkaloids, diterpenoids, and phenolic compounds are present in the roots and leaves. Metabolomic analysis revealed that, in addition to the season and geographical region of the sample collected, the metabolite profiles of TC also depend on the parts of the plant taken as a sample and also the plant's stage of growth. The amounts of secondary metabolites differed between morpho/chemotypes within the TC species. Despite the fact that research on TC began several decades ago, the diversity of phytoconstituents was not appreciated because of a lack of reliable techniques for phytochemical fingerprinting. The uncovering of several novel metabolites was aided by advances in chromatography combined with mass spectrometry. To produce a full metabolomic profile, researchers used mutually complementary techniques. Following that, data analysis and searches against spectrum databases allowed for signal annotation and interpretation of metabolites in large quantities without separating them separately. The current review includes a critical assessment of metabolomic data and an overview of the technique's various applications. It is vital to establish the metrics of quality control of herbal medicines in order to

关键词： Analytical tools metabolomics quality control secondary metabolites Tinospora cordifolia

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

Lipid-nanoparticle-enabled nucleic acid therapeutics for liver disorders

引用

Acta Pharmaceutica Sinica B 2024年第7期14卷 2885-2900页

作者： Porkizhi Arjunan Durga Kathirvelu Gokulnath Mahalingam Ashish Kumar Goel Uday George Zacharaiah alok Srivastava Srujan Marepally Center for Stem Cell Research(A Unit of inStem Bengaluru)Christian Medical College CampusBagayamVellore 632002Tamil NaduIndia Manipal academy for higher education Mangalore 576104KarnatakaIndia Department of Hematology Christian Medical College&HospitalVellore 632004Tamil NaduIndia Department of Hepatology Christian Medical College&HospitalVellore 632004Tamil NaduIndia

Inherited genetic disorders of the liver pose a significant public health *** transplantation is often limited by the availability of donor livers and the exorbitant costs of immunosuppressive *** overcome these limitations,nucleic acid therapy provides a hopeful alternative that enables gene repair,gene supplementation,and gene silencing with suitable *** viral vectors are the most efficient and preferred for gene therapy,pre-existing immunity debilitating immune responses limit their *** a potential alternative,lipid nanoparticle-mediated vectors are being explored to deliver multiple nucleic acid forms,including pDNA,mRNA,siRNA,and ***,we discuss the broader applications of lipid nanoparticles,from protein replacement therapy to restoring the disease mechanism through nucleic acid delivery and gene editing,as well as multiple preclinical and clinical studies as a potential alternative to liver transplantation.

关键词： Lipid nanoparticle Liver disorders Gene therapy Gene editing Nucleic acid delivery pDNA mRNA siRNA ASO Clinical trials

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

Plant based metabolomics:a future prospective and versatile tool for metabolite databases of Curcuma longa

引用

未来食品学报(英文) 2024年第1期4卷 37-47页

作者： Shuvendhu Gupta Amrat Pal Singh Gurpreet Singh Xianting Ding alok Sharma Department of Pharmacognosy ISF College of PharmacyMoga 142001India Department of Pharmaceutical Chemistry ISF College of PharmacyMoga 142001India School of Biomedical Engineering Med-X Research InstituteShanghai Jiao Tong UniversityShanghai 200030China

Sophisticated analytical instruments are used for quality evaluation and scientific validation to compliance the Sophisticated analytical instruments are used for quality evaluation and scientific validation to compliance the market ***,increase in demand of Curcuma longa has led to a high swing in small and medium food *** present review is devoted to an in-depth information on metabolite database of *** from different analytical techniques such as high-performance thin-layer chromatography(HPTLC),liquid chromatography-mass spectrometry,gas chromatography-mass spectrometry and nuclear magnetic *** work highlights different extraction methods,phytochemistry along with structure activity relationship,nutritional profiling,market viability and pharmacology of *** bioactives of *** depends on various factors such as plants growth,temperature,humidity,soil type,collection,drying and extraction *** factors can contribute in quality evaluation of the food supplements if need to be *** introduction of omics approaches can helpful to explore the quality and identification of potential lead of *** results could play an essential role in the area of food-phyto based ***,metabolomics techniques may provide a analytical platfom by combination of different"omics"data souces for future esearch to food sand herbal based products.

关键词： Curcuma longa Omics approaches Multidisciplinary method Quality control Metabolomics

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

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：