检索结果-南通市图书馆

Ballistic resistance and energy dissipation of woven-fabric composite targets:Insights on the effects of projectile shape and obliquity angle

引用

Defence Technology（防务技术） 2023年第3期21卷 14-32页

作者： ibrahim goda UniversitéBourgogne Franche-Comté FEMTO-ST InstituteDépartement Mécanique Appliquée24 Rue de L’Épitaphe25000BesançonFrance

This study aims at investigating the ballistic resistance and energy absorption in woven E-glass composite panels,considering different projectile nose shapes and oblique incidence angles.To that scope,three-dimensional finite element(FE)models of both projectiles and the laminated target are developed and numerical investigations are carried out using Abaqus Explicit solver.The composite damage model’s constitutive law encompasses nonlinear material response,material properties degradation,progressive failure,and an element deletion strategy.The cohesive surface technique is used to represent the interface between two adjacent plies in the laminate,and the traction-separation law is used to characterize the behaviors of interlaminar degradation and failure.Material responses attributable to fiber rupture,matrix cracking,and plasticity caused by micro-matrix cracking due to shear loading are taken into account with suitable damage evolution laws.The computational framework is first validated against the experimental results reported in the literature by performing ballistic impact tests on the target laminate with conical,hemispherical and blunt-ended projectile,and the numerical results showed a good comparison in terms of residual velocity.Subsequently the framework is explored in simulating more complex failure mechanisms,with particular emphasis on the influence of the impact angle of obliquity,a parameter that is not usually analyzed in the literature.In that regard,the effects of normal and oblique impact on the damage morphologies and ballistic behavior of the fabric composite target in terms of energy absorption,impact contact force,and projectile residual velocity are conducted and analyzed,comparatively.The findings showed that the ballistic impact behavior of target composite is substantially influenced by projectile nose shape and incidence angle obliquity.

关键词： resistance cracking composite

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

Histopathological,histochemical and biochemical postmortem changes in induced fatal hypothermia in rats

引用

Forensic Sciences Research 2022年第2期7卷 211-227页

作者： Mahrous Abdelbasset ibrahim Sally Salem Mohammed Hany goda Tammam Rehab ibrahim Abdel-Karim Medhat Mohammed Farag Forensic Medicine&Clinical Toxicology College of MedicineJouf UniversitySakakahSaudi Arabia Forensic Medicine&Clinical Toxicology Department Faculty of MedicineSuez Canal UniversityIsmailiaEgypt Histology and Cell Biology Department Faculty of MedicineSuez Canal UniversityIsmailiaEgypt Forensic Medicine and Clinical Toxicology Department Faculty of MedicineAl-Azhar UniversityCairoEgypt Medical biochemistry Department College of MedicineShaqra UniversityShaqraaSaudi Arabia Medical Biochemistry&Molecular Biology Department Faculty of MedicineBenha UniversityBenhaEgypt

Reaching a postmortem diagnosis of hypothermia is challenging in forensic practice.Therefore,this study was conducted to detect the histopathological,histochemical and biochemical changes that occur in adult albino rats following exposure to induced fatal hypothermia.Twenty-four adult albino rats were divided into the negative control,moderate hypothermia,severe hypothermia and hypoxia groups.Rats in the control group were euthanized when those in the moderate hypothermic group died.Blood samples were collected via heart puncture,and the cerebrum,heart,suprarenal gland,kidney,liver and skeletal muscle were removed to investigate the biochemical,histochemical and histopathological changes.Postmortem assessment depicted significant changes in lipid peroxidation,represented by increased malondialdehyde levels in the studied organs of the rats in hypothermic and hypoxia groups.Histopathological examination of the rats’organs revealed degeneration and necrosis in the hypothermia and hypoxia groups.Sections taken from the severe hypothermic rats revealed a loss of normal cardiac tissue architecture,necrotic changes in the pyramidal cells in the cerebral cortex,and massive necrosis,mainly in the tubules of the renal cortex and medulla.These findings suggest that histological changes might be used as biochemical markers for postmortem diagnosing of fatal hypothermia,particularly in severe hypothermic conditions.

关键词： Forensic sciences forensic medicine legal medicine autopsy forensic pathology histochemical hypothermia

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

Assessment of Groundwater Resources in a Complex Volcanic Reservoir with Limited Data Sets in a Semi-Arid Context Using a Novel Stochastic Approach. The goda Volcanic Massif, Republic of Djibouti

引用

Journal of Water Resource and Protection 2018年第1期10卷 106-120页

作者： ibrahim M. Ahmed Mathieu Le Coz Mohamed Jalludin Paul Sardini Moumtaz Razack University of Poitiers Poitiers France Centre d’études et de Recherches de Djibouti (CERD) Djibouti Republic of Djibouti

This work focuses on the modeling and evaluation of water resources in complex aquifer systems and the use of scarce data. The modeling work is developed based on the GLUE (Generalized Likelihood Uncertainty Estimation) method. This method is still little used in hydrogeology, although its applications in other disciplines such as hydrology proved quite efficient. The study site, located in the Republic of Djibouti (Horn of Africa), is represented by the volcanic massif of goda. The hydraulic properties of this massif are highly heterogeneous since they are associated with fracturing and weathering of the geological formations. The data are too few to enable a conventional modeling approach of this volcanic system. The implementation of the GLUE method in a numerical groundwater flow model allowed developing a stochastic analysis of the spatial distribution of the hydraulic conductivity and the recharge modalities of this complex volcanic system. The hydraulic conductivities range from 10-6 to 10-8 m·s-1 for the basalt and the rhyolite formations (values are yet generally lower for rhyolites) and are higher than 5 × 10-7 for the sedimentary formations. In addition, considering diffuse recharge as the main mechanism by which the precipitation reaches the aquifer results in more consistent groundwater head simulations than considering only indirect recharge. The average recharge amount estimated for the goda aquifer system is 28 mm·yr-1. The results led to a numerical representation of this system, with the least uncertainty. This model was able to estimate the available water resources of this system. This result is important because the goda system supplies water to the city of Tadjourah. Assessment of available resources is vital for the future development of this city. From a methodological point of view, the GLUE method proved very promising for water resources assessment in complex hydrogeological systems for which little data are available.

关键词： Water Resources Stochastic Modeling GLUE Volcanic Systems goda Aquifer Djibouti

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

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

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：