检索结果-南通市图书馆

Development of a Tool Cost Optimization Model for Stochastic Demand of Machined Products

Applied Mathematics 2018年第12期9卷 1395-1423页

作者： Francisco G. Pantoja Victor Songmene Jean-Pierre Kenné oluwole A. Olufayo Michael Ayomoh Mechanical Engineering Department école de Technologie Supérieure (éTS) Montreal Canada Industrial and Systems Engineering Department University of Pretoria Pretoria South Africa

Cutting tool management in manufacturing firms constitutes an essential element in production cost optimization. In order to optimize the cutting tool stock level while concurrently minimizing production costs, a cost optimization model which considers machining parameters is required. This inclusive modeling consideration is a major step towards achieving effectiveness of cutting tool management policy in manufacturing systems with stochastic driven policies for tool demand. This paper presents a cost optimization model for cutting tools whose utilization level is assumed to be optimized in respect of the machining parameters. The proposed cost model in this research incorporated the effects of diversified machining costs ranging from operational through machining, shortage, holding, material and ordering costs. The machining of parts was assumed to be a single cutting operation. Holt-Winters forecasting technique was used to create a stochastic demand dataset for a test scenario in the production of a high-end automotive part. Some numerical examples used to validate the developed model were implemented to illustrate the optimal machining and tool inventory conditions. Furthermore, a sensitivity analysis was carried out to study the influence of varying production parameters such as: machine uptime, demand and cutting parameters on the overall production cost. The results showed that a desired low level of tool storage and holding costs were obtained at the optimal stock levels. The machining uptime had a significant influence on the total cost while tool life and cutting feed rate were both identified as the most influential cutting variables on the total cost. Furthermore, the cutting speed rate had a marginal effect on both costs and tool life. Other cost variables such as shortage and tool costs had significantly low effect on the overall cost. The output trend showed that the feed rate is the most significant cutting parameter in the machining operation, henc

关键词： Inventory Tool Cost Optimization High Value Product Stochastic Demand Machining Parameters

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

Compromises in Vehicle Suspension Design

引用

Journal of Mechanics Engineering and Automation 2012年第7期2卷 441-445页

作者： Emmanuel I. Bello Isaac T. Ogedengbe Amos Osasona Adebisi O. akinola Department of Mechanical Engineering The Federal University of Technology Akure Nigeria

When designing vehicle suspension systems, compromises are usually made when setting the range of values for spring stiffness and damping constant. Suspension parameters are set depending on the operational requirements of the market. Passenger car for example, would require high quality damping while off road vehicle requires high spring stiffness setting. A quarter vehicle suspension model has been used to study the suspension transmissibility in handling and ride at various frequency ratios. The results obtained show that as the frequency ratio increases, transmissibility for handling reduces with increasing suspension stiffness and increases as the damping constant is increased. On the other hand, transmissibility for ride deteriorate as the spring constant is increased but approaches the ideal as the damping constant is increased. The dynamic magnification of the sprung masses reduces while that of the unsprung masses improves as the frequency ratio is increased.

关键词： Sprung masses unsprung masses ride handling transmissibility spring stiffness damping constant frequency ratio.

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

HIV Infection among Newly Diagnosed TB Patients in Southwestern Nigeria: A Multi-DOTS Center Study

引用

World Journal of AIDS 2013年第2期3卷 154-159页

作者： Georgina N. Odaibo Prosper Okonkwo oluwole M. Lawal David O. Olaleye AIDS Prevention Initiative Nigeria Abuja Nigeria Department of Virology College of Medicine University of Ibadan Ibadan Nigeria TB and Leprosy Control Unit Oyo State Ministry of Health Ibadan Nigeria

Backgroud: The burden of TB and HIV infection is estimated to be about 512/100,000 and 3,000,000 people respectively. However, accurate data on TB/HIV co-morbidity in different parts of Nigeria were not available due to limited access to HIV Counseling and Testing (HCT) by individuals with TB infection. This study was designed to determine the true rate of HIV infection among newly diagnosed TB patients by providing comprehensive HCT services in 43 DOTS centers in Oyo State, Southwestern Nigeria. Methods: All patients meeting the case definition for TB suspects who presented at each of the 43 DOTS Centres were counselled and those who consented tested for presence of HIV antibodies using HIV 1/2 Determine, Unigold and Stat-Pak rapid test kits in a serial algorithm. Results: A total of 13,109 TB positive patients were enrolled for the study, out of which 1605 (12.3%) tested positive for HIV antibodies. HIV infection was higher among female (15.5%) than male (9.5%) TB patients (p 0.05). The rates also varied among the age groups, ranging from 4.3% in the 10 - 19 years to 18.0% in the 40 - 49 years age group. A relatively high rate (10.5%) of HIV infection was found among children less than ten years of age. Conclusion: The results of this work show the true burden of TB/HIV in any region in Nigeria for the first time. Higher rate of TB/HIV co-infection among female patients and children are significant and important factors that should be considered in the planning of intervention measures in Nigeria and other TB and HIV endemic countries in Africa.

关键词： HIV TB Co-Infection DOTS Centre Attendees Nigeria

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

Effect of Monosodium Glutamate on Behavioral Phenotypes, Biomarkers of Oxidative Stress in Brain Tissues and Liver Enzymes in Mice

引用

World Journal of Neuroscience 2015年第5期5卷 339-349页

作者： Solomon Umukoro Gabriel Oluwafemi oluwole Henry Egbewunmi Olamijowon Adrian Itiviere Omogbiya Anthony Taghogho Eduviere Department of Pharmacology and Therapeutics College of Medicine University of Ibadan Ibadan Nigeria Department of Pharmacology and Therapeutics College of Health Sciences Delta State University Abraka Nigeria Department of Pharmacology and Therapeutics College of Medicine and Health SciencesAfe Babalola University Ado-Ekiti Nigeria

The effects of oral administration of low doses of monosodium glutamate (MSG) on behavioral phenotypes, biomarkers of oxidative stress in the brain and liver enzymes in mice were evaluated in this study. Mice were treated orally with MSG (100, 250 and 500 mg/kg) daily for 21 days before testing for behavioral phenotypes;memory, anxiety, spontaneous motor activity (SMA) and depression. Thereafter, the brain levels of malondialdehyde (MDA) and glutathione (GSH) as well as the activities of liver enzymes, aminotransferase (AST) and alanine aminotransferase (ALT) were determined spectrophotometrically. MSG did not produce significant (P?> 0.05) impairment of memory in the Y-maze test. It also failed to modify the behaviors of mice in the elevated plus maze and light/dark transition tests of animal models of anxiety. MSG had no significant effect on SMA but produced depressive-like symptoms in the forced swim test at a dose of 500 mg/kg. Moreover, it increased the levels of MDA and decreased GSH concentrations in brain tissues of mice. The activity of AST and ALT were elevated in the blood of MSG-treated mice suggesting liver injury. Taken together, these findings suggested that MSG induced oxidative stress in the brain and impaired liver functions but did not produce any behavioral abnormalities in mice at lower doses.

关键词： Monosodium Glutamate Depression Oxidative stress Liver Enzymes

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

N-acetylcysteine and zinc sulphate abate di-2-ethylhexyl phthalate-mediated reproductive dysfunction in rats:Focus on oxidative and sex hormone receptors mechanisms

引用

Asian pacific Journal of Reproduction 2024年第5期13卷 228-240页

作者： Victor Oghenekparobo Emojevwe Mega Obukohwo Oyovwi Kayode Ezekiel Adewole Peggy Ejiro Ohwin Adeniran Oluwadamilare akinola Alexander Obidike Naiho Eze Kingsley Nwangwa Victor Omo-Idonije Motunrayo Lade-Ige Benneth Ben-Azu Department of Physiology University of Medical SciencesOndo CityOndo StateNigeria Department of Physiology Delta State UniversityAbrakaDelta StateNigeria Department of Physiology Adeleke UniversityEdeOsun StateNigeria Department of Biochemistry University of Medical SciencesOndo CityOndo StateNigeria Department of Pharmacology Delta State UniversityAbrakaDelta StateNigeria

Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechanisms,specifically oxidative stress and sex hormone receptor ***:Thirty-five male Wistar rats were randomly divided into five equal groups(n=7 per group).Group 1 was administered 0.5 mL of distilled water and served as the control *** 2 was given only DEHP(750 mg/kg/day),while group 3,4 and 5 were given DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day),DEHP(750 mg/kg/day)plus ZnSO_(4)(0.5 mg/kg/day),and DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day)as well as ZnSO_(4)(0.5 mg/kg/day),*** treatments lasted for 21 *** were obtained after the rats were sacrificed,and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent *** amount of androgen receptors in the testicles was determined by immunohistochemistry,and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking ***:DEHP decreased reproductive hormones,testicular antioxidant enzymes,increased malondialdehyde levels,and negatively impacted histology of the pituitary and *** or ZnSO_(4) treatment showed a marked improvement in testicular antioxidant status and hormone levels,as well as a positive effect on the histology of the pituitary and *** combination of both treatments appeared to be more *** affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling,which can further result in dysfunction of hormones related to ***,NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors,as well as gonadotropin-releasing hormone receptors,when compared to ***:The pos

关键词： Di-2-ethylhexyl phthalate Testosterone Androgen receptor 5α-reductase Oestrogen Luteinizing hormone

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

Finite Element Modeling Of Low Heat Conducting Building Bricks

引用

Journal of Minerals and Materials Characterization and Engineering 2012年第8期11卷 800-806页

作者： O. O. oluwole J. S. Joshua H. O. Nwagwo Department Of Mechanical Engineering University Of Ibadan Nigeria

Heat conduction through conventional and interlocking building bricks with cavities was studied in this work. Heat transfer analysis was carried out using MATLAB? partial differential equation toolbox. Regular and staggered hole arrangements were studied. Results showed that four staggered holed interlocking bricks were effective in thermal resistance into the bricks and increasing the holes beyond four did not give any thermal resistance advantage. For the conventional bricks staggered holes did not give any thermal resistance advantage but the four-holed bricks were also adjudged to be effective in thermal resistance into the brick surface. Increasing the number of holes beyond four in conventional bricks did give some thermal resistivity advantage but very minimal. Structural strengths of holed bricks were not considered in this study.

关键词： Building Bricks Finite Element Modeling Heat Conduction

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

Sexuality and Emergency Contraceptive Practice among Female Undergraduates in Lagos, Nigeria

引用

Open Journal of Obstetrics and Gynecology 2020年第6期10卷 836-854页

作者： Yusuf Abisowo Oshodi Fatimat Motunrayo Akinlusi Akaninyene Akan Uduosoro Joy Onyinyechi Agbara Kabiru Afolarin Rabiu Oluwarotimi Ireti akinola Department of Obstetrics and Gynecology Lagos State University Teaching Hospital Ikeja Nigeria

Background: Young people, especially those in tertiary institutions are vulnerable to unplanned and unprotected sexual intercourse which predisposes them to unintended pregnancies and subsequently unsafe abortions. One of the key interventions for reduction of unwanted pregnancies and unsafe abortions is effective use of emergency contraceptives. Objectives: To assess the sexuality, perception, attitude towards and determinants of usage of emergency contraception among female undergraduates in Lagos, Nigeria. Methods: Cross-sectional survey conducted in June 2016 among 805 female students of the Lagos State University. Data were collected through structured self-administered questionnaire by obtaining information on demography, sexual and contraceptive history, perception, attitude towards and use of emergency contraceptives. Data obtained were analyzed using SPSS version 16. Chi-square and logistic regression models were applied to variables to test for significance that predicts

关键词： Sexuality Unprotected Intercourse Unintended Pregnancy Emergency Contraceptives Practice

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

Investigation of Properties of Thixoprocessed LM4

引用

Journal of Minerals and Materials Characterization and Engineering 2012年第1期11卷 107-115页

作者： A.V. Adedayo S.A. Ibitoye O.O. oluwole K.M. Oluwasegun Department of Materials Engineering Obafemi Awolowo University Ile-Ife Nigeria Department of Mechanical Engineering University of Ibadan Ibadan Nigeria

Thermomechanical treatment on cast Al-Si-Cu alloy (LM4) was carried out. The aim is to determine effects of degree of cold work, slurry thermal treatment and soaking time on the tensile strength, ductility, hardness and microstructure of the alloy. LM4 was prepared and cast in sand mould into rods of Φ50 mm and 200 mm in length. The prepared rods were then thermally treated at 635°C which fall within the slurry region of the alloy. The heated samples were soaked at this temperature for various times of: 5, 10, 15 and 20 min. A none-treated sample was also kept as control specimen. The thermally treated rods were subjected to various degrees of cold work. 10 %, 15%, 20%, 30% degrees of cold work were used. Hardness, tensile strength and elongation of the samples were determined. The metallographic examination of the samples was also carried out. Results of mechanical property test show sensitivity to degree of cold work, thermal treatment soaking time. The microstructures of the alloy also show significant modifications as a result of thermal treatment.

关键词： SSM thixocasting rheocasting

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

Compressive and Flexural Behaviour of Unstressed Concrete Substructure in Cassava Effluent Contaminated Soils

引用

Open Journal of Civil Engineering 2015年第2期5卷 239-248页

作者： Adekunle P. Adewuyi oluwole A. Olaniyi Oladipupo S. Olafusi Ademola S. Fawumi Department of Civil Engineering Federal University of Agriculture Abeokuta Nigeria Department of Civil Engineering Ladoke Akintola University of Technology Ogbomoso Nigeria

Concrete research is gradually shifting from the conventional strength-based approach to durability-centred in the past decade. Durability is the measure of the robustness of constructed facilities against deterioration tendencies. The rate of deterioration is affected by the loading condition, and more importantly the physical and chemical nature of the host environments. This paper reports the experimental investigation of unstressed concrete substructure in the natural (uncontaminated) and cassava’s hydrocyanide effluent-polluted soils on the compressive and flexural strengths of buried concrete specimens for a maximum of 84 days. The compressive strengths of the cubes were tested every 7 days until the 84th day, while the beams were only subjected to third-point loading flexural tests at age 84 days. The compressive strength of concrete specimens in the two soil environments increased, though the trend was lower in the polluted soil. The strength reduced by 2.50% to 9.47% between the 7th and 28th days, but steadily between the 28th and 84th days with strength loss of 9.95% (COV = 2.64%). The load-deflection curves were quadratic for the beams in the two geo-environments. The beams in cyanide-polluted soil lost 34.5% of its flexural stiffness, while its loss of load-carrying capacities at the first crack and ultimate failure was 15.8% and 20% respectively. Higher degree of deterioration is certain for loaded concrete substructures in similar conditions. Hence, prior knowledge of soil chemistry is crucial to determining suitable concrete grade and nominal cover for durable substructural elements.

关键词： Strength Loss Flexural Stiffness Soil Contamination Chemical Attack Deterioration Cyanide

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

Jobelyn^(■), a Sorghum-Based Nutritional Supplement Attenuates Unpredictable Chronic Mild Stress-Induced Memory Deficits in Mice

引用

Journal of Behavioral and Brain Science 2015年第13期5卷 586-597页

作者： Solomon Umukoro Osarume Omorogbe Oritoke Modupe Aluko Taghogho Anthony Eduviere Olatunde Owoeye Oluwafemi Gabriel oluwole Neuropharmacology Unit Department of Pharmacology and TherapeuticsUniversity of IbadanIbadanNigeria Department of Pharmacology and Therapeutics College of Health SciencesOsun State UniversityOsogboNigeria Department of Pharmacology and Therapeutics College of Medicine and Health SciencesAfe Babalola UniversityAdo-EkitiNigeria Department of Anatomy Faculty of Basic Medical SciencesUniversity of IbadanIbadanNigeria

The ability of an organism to adapt to aversive stressful situations or life challenging circumstances is very crucial to its state of health and survival. However, breakdown in adaptation due to persistent uncontrollable stress, leads to impairment of bodily functions and onset of a variety of pathological disorders especially memory decline. This study was designed to evaluate the effect of Jobelyn®(JB), a potent antioxidant sorghum-based food supplement on unpredictable chronic mild stress (UCMS)-induced memory impairment in mice. Male Swiss mice were given JB (5 - 50 mg/kg, p.o) 30 min prior to exposure to UCMS for 14 consecutive days before testing for memory. Thereafter, the serum corticosterone level was estimated by using ELISA kits. The levels of malondialdehyde (MDA) and glutathione (GSH) as well as acetylcholinesterase activity were estimated in the brain homogenate using spectrophotometer. Histology of the brain tissues and estimation of the populations of viable neurons in the hippocampal region were done after staining with hematoxyline and eosin. Our results showed that JB reversed memory impairment and suppressed corticosterone concentrations induced by UCMS. Moreover, JB reduced oxidative stress in the brain of UCMS-mice as shown by decreased MDA levels and elevated GSH concentrations. It also decreased brain acetylcholinesterase activity when compared with chronic stress group (p < 0.05). Furthermore, JB (5 - 10 mg/kg, p.o) offered significant protection against UCMS-induced degeneration and death of neuronal cells of the cornu ammonis 3 (CA3) of the hippocampal region of the brain indicating neuroprotection. Taken together, these findings suggest that JB attenuates memory deficits induced by UCMS in mice and may be useful therapeutically for stress-related cognitive dysfunctions. The reduction in the levels of serum corticosterone, antioxidation, neuroprotection and inhibition of cholinesterase enzyme might be contributing significantly to the

关键词： Jobelyn^(■) Unpredictable Chronic Mild Stress Memory Performance Oxidative Stress Neuroprotection

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：