检索结果-南通市图书馆

Metal contamination assessment in the urban stream sediments and tributaries of coastal area southwest Nigeria

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2015年第3期34卷 431-446页

作者： Abiodun M.Odukoya olumuyiwa Akande Department of Geosciences University of Lagos

A geochemical assessment of the fifty surface stream sediments from Ikorodu Southwest Nigeria was carried out to determine the level of contamination. The sediments were dried, disaggregated and sieved to \75 lm fraction for geochemical analysis, using the aqua-regia digestion technique and inductively coupled plasma mass spectrometry. Major elements showed the following trend Fe [ Al [ Ca [ Na [ Mg [ K [ P [ Ti and were below the average shale concentration, except for Na in one *** from factor and correlation analyses showed two groups of trace elements Ni, Co, Mn, U, Th, Sr, V, la, Cr, Ba,Sc, Ga, Cs, Nb, Rb, Y,Ce and Mo, Pb, Zn, As, Cd, Sb, Sn, Zr,which were from geogenic and anthropogenic sources, respectively. The enrichment factor showed that Cd, Bi, Pt, Mo and Ag were, for all samples, within background concentrations, except those of the Ogun River and the Owode Onirin, which showed significant enrichment of Cd, Zn, Cu,Pb and Ag, depletion to minimal enrichment for Bi, Mo and moderate enrichment for Pt. The contamination degree ranged between 1.25 and 143.79. The highest value was found at Owode Onirin and the lowest, at Igbonla 7. The geoaccumulation index showed that all the stream sediments ranged between practically uncontaminated to moderately to highly contaminated—with Pb, Sn, Zn, Cd, Cu, Cr, Zr and Ba. The potential ecological risk factor and environmental risk index(IER) showed that all of the samples were within the class of low to medium contamination risk, except samples from the Owode Onirin, which fell within the class of very high risk to extremely high risk respectively.

关键词：水系沉积物污染评价尼日利亚沿海地区电感耦合等离子体质谱法西南富集因子分析环境地球化学

Physical and mechanical characteristics of composite briquette from coal and pretreated wood fines

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2021年第5期8卷 1088-1098页

作者： Adekunle Adeleke Jamiu Odusote Peter Ikubanni olumuyiwa.la.ode Madhurai Malathi Dayanand Pasawan Department of Mechanical Engineering Landmark UniversityOmu-AranNigeria Department of Materials and Metallurgical Engineering University of IlorinIlorinNigeria Department of Mechanical Engineering University of IlorinIlorinNigeria Metal Extraction and Recycling Division National Metallurgical LaboratoryJamshedpurIndia

Melina wood torrefied at 260℃ for 60 min was agglomerated with lean grade coal fines into composite briquettes using pitch as *** biomass(3%-20%)and coal fines(80%-97%)were blended together to produce the composite briquettes under a hydraulic press(28 MPa).The briquettes were cured at 300℃.Density,water resistance,drop to fracture,impact resistance,and cold crushing strength were evaluated for the composite *** proximate,ultimate,and calorific value analyses were carried out according to different ASTM *** studies were carried out using scanning electron microscope and electron probe microanalyzer equipped with energy dispersive *** Transform Infrared Spectrophotometer(FTIR)was used to obtain the functional groups in the raw materials and *** density of the composite briquettes ranged from 0.92 to 1.31 g/cm^(3) after *** with95%).The highest cold crushing strength of 4 MPa was obtained for briquettes produced from 97%coal fines and 3%torrefied *** highest drop to fracture(54 times/2 m)and impact resistance index(1350)were obtained for the sample produced from 97%coal and 3%torrefied *** fixed and elemental carbons of the briquettes showed a mild improvement compared to the raw *** peaks from FTIR spectra for the briquettes shows the presence of aromatic C=C bonds and phenolic OH *** composite briquettes with up to 20%torrefied biomass can all be useful as fuel for various applications.

关键词： Composite briquettes Lean grade coal Torrefied biomass Physico-mechanical properties Combustion properties

Review of economic and environmental benefits of earthen materials for housing in Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2017年第4期6卷 519-528页

作者： olumuyiwa Bayode Adegun Yomi Michael Daisiowa Adedeji Department of Architecture Federal University of Technology Akure Nigeria School of Architecture and Planning University of the Witwatersrand Johannesburg South Africa

Solutions to housing problems must deal with the issue of building materials - especially advancing those which lower construction cost and costs to the environment. This paper aggregates and reviews empirical evidences to show the advantages and disadvantages of earthen construction materials in terms of cost, energy and thermal properties. We reviewed 136 academic outputs from 17 African countries. Apart from a few studies that differ, literature concurs that earthen construction materials are generally cheaper, cleaner and more thermally comfortable. Notwithstanding the advantages, the level of uptake is presently low. Earthen materials＇ strength and durability are key limitations. We identify possible areas for future research and present specific recommendations that can promote the uptake of earthen materials for housing construction in African cities.

关键词： Housing Building materials Sustainabitity Energy Thermal comfort,Africa

Design and development of an improved traffic light control system using hybrid lighting system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traffic and Transportation Engineering(English Edition) 2017年第1期4卷 88-95页

作者： Michael Osigbemeh Michael Onuu olumuyiwa Asaolu Department of Electronics and Computer Engineering Nnamdi Azikiwe UniversityAwkaNigeria Department of Physics Federal University Ndufu-Alike IkwoEbonyiNigeria Department of Systems Engineering University of LagosLagosNigeria

The deployment of light emitting diodes （LEDs） based traffic system control created the problem of dim displays when ambient light is similar to traffic lights. It causes some drivers＇ disability of seeing and obeying traffic signs. This makes drivers violate traffic rules. In this paper, an attempt to use hybrid lighting technology to mitigate this problem was developed. Incandescent lightings with deployed halogen bulbs provided an instan- taneous source of highly efficacious illumination which is brighter than the drivers＇ ambient lights （both daylight, electrical lights and their reflections）, which can help drivers get access to enough warning and help them initiate traffic safety warning as necessary. The halogen lightings also offered the required high current draw needed in electrical circuitry to help brighten the LED displays. The problem of heat generated was eliminated by aerating the T-junction traffic light control unit designed for this technology. The result of hybrid lighting system design was found to be high luminosity and capability of gaining driver attention in real-time. It also allowed enhanced sign＇s image detection and pro- cessing for smart based technologies by providing the ＂light punch＂ needed for a wide range of visual concems.

关键词： Traffic lights Luminosity Halogen incandescence Light efficacy Energy saving

An improved model for severe slugging stability criteria in offshore pipeline-riser systems

在线全文

学校读者我要写书评

暂无评论

Petroleum Research 2022年第3期7卷 318-328页

作者： Adesina Fadairo Chinemerem Obi Kegang Ling Vamegh Rasouli olumuyiwa Aboaba Olumide Gbadamosi Department of Petroleum Engineering University of North DakotaUnited States Department of Petroleum Engineering University of Texas A&MUnited States Schlumberger Oifield Services Nigeria Repsol NorgeAs Norway

Flow assurance has been a major challenge in petroleum production systems especially in offshore operations where severe slugging is a dominant aching *** is characterized by pulsating flow behavior which impacts the reservoir productivity,pipeline-riser systems,and surface facilities(separator).The only means so far,of delivering reservoir fluids from offshore wells to the separator at the surface is by pipeline-riser systems where slugging is most prominent and oftentimes *** passive and active measures have been deployed over time to mitigate the associated problem,there is the need to develop a predictive tool for mitigating offshore slugging in the riser *** study involves the use of a model and analysis approach to eliminate severe slugging based on the balance of forces acting on the pipeline-riser *** stability criteria which consider accumulation and frictional pressure drops have been *** current approach is solely physicsdriven,to predict the corresponding liquid and gas velocities at which the fluctuations would be severe when producing multiphase fluids through pipeline-riser *** balancing the forces acting on a riser-pipeline system and accounting for frictional and accumulation effects,two hydraulic flow modeling approaches have been used in this study to improve the criteria for predicting the condition of severe *** developed criteria were computed using MATlaB/Simulink and a severe slugging flow map was ***“new study 1”and“new study 2”showed a 16%and 13%increase respectively in predicted unstable cases than the Malekzadeh *** criteria were tested at different separator *** Taitel and Jansen criteria could not predict severe slugging at elevated separator ***,the developed flow maps using the“new study 1”are more reliable than the“new study 2”.This is because the“new study 2”approach over defines the physics of severe *** cr

关键词： Severeslugging Stability criteria Offshore Pipeline-Riser systems

Local Knowledge of Farmer Communities in the Use of Organic Fertilizers to Increase Cashew Production in Buton Utara Regency, Southeast Sulawesi Province, Indonesia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Sociology Study 2023年第4期13卷 188-195页

作者： Syahrun la Niampe Rahmat Sewa Suraya la ode Topo Jers laxmi Alias la Aso Department of Archeology Cultural Studies FacultyKampus Hijau Bumi TridharmaHalu Oleo UniversitySoutheast CelebesIndonesia

Local knowledge has an important role in agricultural *** study aims to describe the local knowledge of farming communities about the use of organic fertilizers as a strategy to increase cashew production in Buton Utara Regency,Southeast Celebes,*** research method used is a qualitative approach with data collection techniques using in-depth interviews and *** research results showed that the farming community in this area has in-depth local knowledge of how to make and apply effective organic fertilizers sourced from the surrounding natural ***,there are challenges in access to the organic materials needed and constraints in the widespread implementation of organic *** study recommends strengthening education and training programs to increase farmers’awareness and skills in using organic fertilizers.

关键词： local knowledge farmers organic fertilizers cashew

3D Seismic Analysis of the Gas Hydrate System and the Fluid Migration Paths in Part of the Niger Delta Basin, Nigeria

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2017年第6期16卷 1027-1034页

作者： AKINSANPE olumuyiwa T. ADEPELUMI Adekunle A. BENJAMIN Uzochukwu K. FALEBITA Dele E. Department of Geology Obafemi Awolowo University Ile-Ife 220282 Nigeria

Comprehensive qualitative and semi-quantitative seismic analysis was carried out on 3-dimensional seismic data acquired in the deepwater compressional and shale diapiric zone of the Niger Delta Basin using an advanced seismic imaging tool. The main aim of this work is to obtain an understanding of the forming mechanism of the gas hydrate system, and the fluid migration paths associated with this part of the basin. The results showed the presence of pockmarks on the seafloor and bottom simulating reflectors(BSRs) in the field, indicating the active fluid flux and existence of gas hydrate system in the area. In the area of approximately 195 km^2 occupying nearly 24% of the entire study field, three major zones with continuous or discontinuous BSRs of 3 to 7 km in length which are in the northeastern, southern and eastern part of the field respectively were delineated. The BSR is interpreted to be the transition between the free gas zone and the gas hydrate zone. The geologic structures including faults(strike-slip and normal faults), chimneys and diapirs were deduced to be the main conduits for gas migration. It is concluded that the biogenic gases generated in the basin were possibly transported via faults and chimneys by advection processes and subsequently accumulated under low temperature and high pressure conditions in the free gas zone below the BSR forming gas hydrate. A plausible explanation for the presence of the ubiquitous pockmarks of different diameters and sizes in the area is the transportation of the excessive gas to the seafloor through these mapped geologic structures.

关键词： pockmark bottom simulating reflector gas hydrate Niger Delta Basin

Effects of Span Length and Additional Structure on Flow-Induced Transverse Vibration Characteristic of a Cantilevered Rectangular Prism

在线全文

学校读者我要写书评

暂无评论

Journal of Flow Control, Measurement & Visualization 2020年第3期8卷 102-120页

作者： la ode Ahmad Barata Takahiro Kiwata Takaaki Kono Toshiyuki Ueno Graduate School of Natural Science and Technology Kanazawa University Kanazawa Japan School of Mechanical Engineering Kanazawa University Kanazawa Japan School of Electrical and Computer Engineering Kanazawa University Kanazawa Japan

We consider the effects of the aspect ratio L/H (where L is the length of a prism, and H is the height of a prism normal to the flow direction) and the size of additional structures (which are a plate and a fin on the surface of a prism) on a vibration characteristic of a cantilevered rectangular prism. The present research is intended to support the analysis of energy harvesting research on the flow-induced vibration in water flow using a magnetostrictive phenomenon. The prisms are constructed from stainless steel and mounted elastically to a plate spring attached to the ceiling wall of the water tunnel. The prisms with aspect ratios of L/H ≥ 5 have reasonably identical vibration characteristics. However, the difference in the vibration characteristic appears distinctly on a rectangular prism with an aspect ratio of L/H = 2.5. The rectangular prism with an aspect ratio of L/H = 10 and a side ratio of D/H = 0.2 has a stable and large response amplitude and oscillates with a lower velocity. The length of the added plate and the size of the added fin influence the velocity of vibration onset. If the length of the added plate and fin size on the rectangular prism with D/H = 0.2 becomes large, the curve of the response amplitude shifts to that of the rectangular prism with D/H= 0.5. The response amplitude of the rectangular prism with/without plate or fin is found to be related to the second moment of area of the prism.

关键词： Flow-Induced Vibration Cantilevered Rectangular Prism Aspect Ratio Stepped Prism Finned Prism Response Amplitude Resonant Reduced Velocity

Hepatocurative potential of Vitex doniana root bark,stem bark and leaves extracts against CCl_4-induced liver damage in rats

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Biomedicine 2014年第6期4卷 480-485页

作者： James Dorcas Bolanle Kadejo Olubukola Adetoro Sallau Abdullahi Balarabe Owolabi olumuyiwa Adeyemi Department of Biochemistry Ahmadu Bello University

Objective:To evaluate the hepatocurative effects of aqueous root bark,stem bark and leaves of Vitex doniana in carbon tetrachloride(CCl_4)induced liver damage and non induced liver damage albino ***:A total of 60 albino rats(36 induced liver damage and 24 non induced liver damage)were assigned into liver damage and non liver damage groups of 6 rats in a *** animals in the CCl_4 induced liver damage groups,were induced by intraperitoneal injection with a single dose of CCl_4(1 mL/kg body weight)as a 1:1(v/v)solution in olive oil and were fasted for 36 h before the subsequent treatment with aqueous root bark,stem bark and leaves extracts of Vitex doniana and vitamin E as standard drug(100 mg/kg body weight per day)for 21 d,while the animals in the non induced groups were only treated with the daily oral administration of these extracts at the same *** administration of CCl_4 was done once a week for a period of 3 ***:There was significant(Planine aminotransferase,aspartate aminotransferase and alkaline aminotransferase(ALT,AST and ALP)and significant(Plant parts(root bark,stem bark and leaves)possess significant hepatocurative properties among other therapeutic values justifying their use in folklore medicine.

关键词： Vitex doniana Hepatocurative Liver damage Creatinine Carbon tetrachloride