bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-Time and High-Performance Attitude and Heading Reference System Based on MIMU/Magnetometers
Authors: Qin Wei , Yuan Wei Zheng , Chang Hong Long , Xue Liang , Yuan Guang Min
Published: March 2009

In the paper, an attitude and heading reference system based on MIMU/magnetometers with moderate accuracy is presented. To meet the requirements of the real-time measurement, a master/slave CPU structure is proposed in order to improve the data refresh rate effectively. In the algorithm part, an adaptive extended Kalman filter equation is applied in the system, where the filter equation uses three tilt angles of attitude and three bias errors for the gyroscopes as state vectors, the measurements of three accelerometers and magnetometers are used to drive the state update. When the system is in dynamic mode, the measured values of the accelerometers consist of the gravity vector and the dynamic accelerations, an adaptive extended Kalman filter tunes its gain automatically based on the system dynamics sensed by the accelerometers to yield optimal performance. The experiment result shows that the attitude and heading angle errors are within 0.2 deg and 0.5 deg respectively in stationary mode, and the result can reflect the attitude angles reasonably in dynamic mode.
A Bulk RF MEMS Switch by Silicon-to-GaAs Bonding
Authors: Lu Le , Zhu Jian , Jian Shi Xin , Chen Chen
Published: March 2009

. A Bulk RF MEMS switch is present in this paper. The beam structure and transmission line are separated fabricated on silicon and gallium arsenide (GaAs) wafer. The beam structure, up electrode, contact and anchor are fabricated on the silicon wafer. And transmission line and down electrode are made on the GaAs substrate. Two parts of the switch are bonded together by wafer bonding using gold layer as seed. The total area of the switch is 600 um X 600 um.
Fabrication of Nanomechanical Resonators in Silicon Nitride
Authors: Liu Mei , Zhu Jian , Jia Shi Xing , Zhuo Min , Lu Le , Gong Quan Cheng
Published: March 2009

We report our efforts towards fabricating nanomechanical resonators patterned by optical lithography in silicon nitride. Optical lithography has advantages of low cost and high efficiency over electron-beam lithography. Double clamped beam resonators with thickness 150nm, length and lateral dimensions 20um, 800nm have been designed. Through utilizing reactive ion etching and controlling gas flow, reaction time of CF4 and O2 plasma and power of the upper and lower electrode, nanomechanical resonators with lateral dimensions within 200nm are demonstrated.
A New Method Based on Electropolymerizing Staphylococcal Protein A to Immobilize Antibody in Micro Amperometric Immunosensor
Authors: Sun Jhi Zhou , Bian Chao , Qu Lan , Xia Shan Hong
Published: March 2009

A new method has been developed and applied in a micro amperometric immunosensor to immobilize antibody with electropolymerized staphylococcal protein A (SPA). SPA is usually used directly as an immunoadsorbent and can achieve the binding of IgG very well. In this paper, pyrrole doped with SPA was co-electropolymerized onto the working electrode surface by cyclic voltammetry in 10 minutes. It effectively immobilized SPA on the surface of the working electrode for orientation-controlled immobilization of capture antibodies. This method as a controllable and convenient manipulation can modify the sensing surface more rapidly with less consumption of reagent (10μL), which is proper to the micro immunosensor. As an application to test the validity of this method, Salmonella typhimurium (S. typhimurium) with the concentration of 102cfu/ml could be detected by this immunosensor, which shows the good property of the sensor and proves the feasibility of the method applied for the immobilization of antibody. It is potential to develop a biosensor that can be used for convenient, low-cost and real-time sensing of pathogens in food products.
Design and Simulation of a Micromachined CMOS Temperature Sensor
Authors: Ma Hong Yu , Huang Qin Gan , Qin Ming
Published: March 2009

A design and simulation of a fully CMOS compatible micromachined multilayer cantilevers-based environmental thermometer are presented. The operation principle of the structure is depending on the mismatch effect of thermal expansion coefficient and the piezoresistive effect of polysilicon in CMOS process. Upon temperature variation, the deformation of the multilayer cantilever resulted from the large thermal expansion coefficient mismatch of different materials can be sensed and translated to an electrical voltage output by using a symmetric piezoresistive Wheatstone bridge. The mechanical characteristics of the device are analyzed with the extension of bi-layer Timoshenko model and the output of the read-out circuit is also simulated. The calculation and simulation show that the device with bi-direction deformation may have wide temperature range from -100 to 100°C and sensitivity about 0.15mV/°C, which fit the demand of radiosonde for environmental temperature measurement. This sensor may also have other favorable features, such as micro size, low-cost due to its working principle and compatibility with commercial CMOS process.
A Uncooled α-Si Infrared Detector Using Polyimide as Thermal Isolation Layer
Authors: Fang Hua Jun , Liu Xing Ming , Liu Li Tian
Published: March 2009

a new structure of the uncooled amorphous silicon (α-Si) infrared detector has been fabricated and characterized. The structure with thermal isolation and infrared absorption based on polyimide (PI) and bottom metal reflective layer is put forward. The fabrication process of the IR detectors is described. The temperature coefficient of resistance (TCR) of α-Si resistance has been investigated. The measurements show that the TCR is up to -2.8%. The detectivity of 1.7×108 cmHz1/2W-1 is achieved with chopping frequency of 30Hz at a bias voltage of 5V. Measurement results indicate that the polyimide layer exhibits excellent thermal isolating characteristics and the unique sandwich IR absorption structure is beneficial to the enhancement of detectivity. Compared with other techniques, the IR detectors using PI as thermal isolation layer are not only with simpler process, lower cost and higher yield, but also suitable for the application of large-scale uncooled infrared focal plane arrays (IRFPA).
A Study on the Assembly and Improvement of Electrical Contact between Carbon Nanotube and Microelectrode
Authors: Tian Xiao Jun , Wang Yue Chao , Dong Zai Li
Published: March 2009

Nowadays research on nano-electronic device based on carbon nanotube (CNT) raises much interest among researchers, but in the fabrication process, crucial problems exist in making and improving the electrical contact between CNT and microelectrode. Here pulse gas alignment method, combined with nanomanipulation technology based on atomic force microscope (AFM) if necessary, is proposed for the first time to assemble and make electrical contact between CNT and microelectrode. After the assembly, a processing technique of applying sweeping voltages is performed for producing electrical current induced local Joule heat, which will decompose and remove the sodium dodecyl sulfate (SDS) molecules adsorbed on the CNT and at the interface region, or even have some annealing effect, to reduce the contact resistance between CNT and microelectrode and thus to improve the electrical contact. Experiments of assembly and improvement of electrical contact between multi-wall carbon nanotube and microelectrode are performed to verify the effectiveness of the proposed methods
Design of a Hybrid-Type Electrostatically Driven Microgripper Integrated Vacuum Tool
Authors: Sun Li Ning , Chen Tao , Chen Li Guo , Li Xin Xin
Published: March 2009

This work is focused on design and fabrication of a hybrid-type electrostatic silicon microgripper integrated vacuum tool. Vacuum tools are integrated in this novel microgripper in order to improve its pick and place capability. Surface and bulk micromachining technology is employed to fabricate the microgripper from single crystal silicon wafer (i.e., no silicon on insulator wafer is used). And the bonding technology is used to form the gas pipes for the vacuum tool. The linear motion of the microactuator is converted into a rotational gripping motion by a system of spring beams. At a driving voltage of 80V, a deflection of 25μm at the arm tip of the gripper is achieved.
Experimental Study on Hot Embossing of Micro/Nano Grating
Authors: Liang Yong , Liu Chong , Sun Huan Li , Li Jing Min , Liu Jun Shan , Gao Xian Ni
Published: March 2009

During hot embossing process of polymer MEMS devices, the parameters such as temperature, pressure and time are important for the duplication precision of patterns. In this work, a novel method of hot embossing lithography for replication of multiple nano bar structure mould was conducted. The effects of hot embossing temperature and pressure on fabrication precision were studied. Linewidth of the pattern on the mould is from 71nm to 980nm. The replicas of nano bar structure were fabricated on the PMMA (polymer methyl methacrylate) layer with silicon substrate. The effects of hot embossing and demoulding temperature on replicating quality were also discussed. Experimental results indicate that higher demoulding temperature help to lessen PMMA leftover and improve the duplication quality. The hot embossing and dmoulding temperature of 110°C～120°C and 60°C～70°C were obtained to produce high quality duplication of multiple nano bar structures. Micro-grating replicas were also fabricated and demonstrated in this paper.
The Effect of Temperature on Field Emission Current
Authors: Zhuang Gen Huang , Wang Ling Yun , Sun Dao Heng
Published: March 2009

In this paper, we present our recent works on the measurement of field emission performance of silicon tip arrays and investigate the thermal instability of emission current by measuring the emission current as the function of time under three different cooling conditions—natural free radiation，contact conduction and air forced convection respectively. Draw the conclusions that field emission performance of the silicon-based emitters is quite sensitive to the temperature change and resistive heating produced as emission current flowing through the apex of silicon emitters induces the instability of emission current.
Preparation and Property Studies of TiO2 Membrane/ Macroporous Silica Composite Microspheres
Authors: Gao Zhi Qiang , Song Zhong Rong , Tao Han , Ling Li Xin
Published: March 2009

Using Quartz particles as the repeat-agents, commercial water glass as the raw material, butyl titanate as the source of titanium, the TiO2 Membrane/ Macroporous Silica gel composite microspheres were successfully prepared. The uniformity transparent TiO2 Membrane on the surface of Silica gel microspheres(SM) was inducted by sol-gel method and dipping extracted method. The structure and performance of the microspheres were characterized by Infrared Spectroscopy (IR) and X-ray diffraction (XRD). The results showed that the composite microspheres were irregular porous materials and their average diameter was 2.18 mm. The crystal type of the TiO2 film was anatase and its average size was 15 nm. Illuminated for 7.5h, the degradation ratio of the composite microspheres was up to 85%. The properties of photocatalysis would be increased with the increasing of the amount of the quartz.
Reduction of Fire Incidents due to Electrical Faults in Buildings
Authors: Onohaebi S.O. , Apeh S.T.
Published: March 2009

The prevalence of fire incidents in buildings resulting from electrical faults due to haphazard planning and installations have reached an alarming state in the country. Thus, this paper highlights the advantages to be derived from a properly designed and maintained electrical engineering services in buildings. The basic theory, methodology and technical considerations involved in the design and maintenance of electrical services are discussed in this paper. These were in consonance with both National and International regulations governing electrical services design and installations, such as International Electro-Technical Commission (IEC), Institute of Electrical Engineers (IEE) Regulation, Illumination Engineering Society (IES) Codes and Electrical Act of Federal Republic of Nigeria. An office apartment was used as a case study. In order to ensure safety of equipment and consumers, relevant tests to be carried out in the installation were also prescribed in this paper. Lack of proper design, poor maintenance, sub-standard materials such as cables, luminaries, electrical panels, switches and sockets, in-appropriately sized protective devices, unqualified personnel, up-patriotic attitude and wrong ultilization of electric power were identified as major factors responsible for electric faults in buildings. The paper therefore proffer recommendations to the rampant electrical faults resulting in fire incidents in both private and public buildings and the need to inculcate maintenance culture in their operations to minimise deterioration of electrical installations in buildings.
Durability-Based Appropriateness of Sawdust Concrete for Rigid Pavement
Authors: Ogundipe O.M. , Jimoh Y.A.
Published: March 2009

In this paper, sawdust concrete with nominal mixes 1:1:2, 1:1½:3, 1:2:4, 1:3:6 and 1:4:8 were subjected to durability test. The 28-day water absorption of the mixes are 5.69, 8.97, 8.29, 7.83 and 11.11%, 28-day linear shrinkages are 0.67, 0.50, 1.83, 1.83 and 1.95%, respectively. The 28-day thermal conductivities are 0.229, 0.232, 0.229, 0.223 and 0.176W/m.K., respectively. The 28-day compressive strengths of mixes 1:1:2 and 1:1½:3 are 18.33 and 8.78 N/mm2, respectively, while their 28-day flexural strengths are 1.71 and 1.33 N/mm2, respectively. These values indicated that they are good and durable concrete and can be used for construction of rigid pavement.
Analysis of Generating Capacity Dynamics of the Nigerian Power System between 1963 and 2020
Authors: Melodi Adegoke Oladipo
Published: March 2009

A study of the growth dynamics of the installed capacity of the Nigerian Power System from 1963 to date was done. Perspective available generating capacity was estimated based on service life of existing installed capacity. The sufficiency of generating capacity for future normal operating modes of the system was estimated based on a power load growth forecast from 2003 to 2020. An analysis of the results shows that all the installed capacity since 1963 to the late 80s would have expired by 2020 i.e outlived their rated service lives. At present, only about 4.9 GW (80%) of total installed capacity is valid. Considering the national goal of significant economic development and estimated load forecast of over 8 GW by 2020, there is an urgent need to renovate or replace expired generating units besides the planned building of new power stations which have long gestation periods.
Dielectric Strength, Breakdown Voltage and Acidity Test with Respect to Transformer Insulating Oil
Authors: Adejumobi I.A.
Published: March 2009

This paper presented the qualitative assessment of transformer insulating oil. The breakdown voltage, dielectric and acidity tests were electrically and chemically carried out on sixteen samples of transformer insulating oil collected from various serving distribution transformers in Ilorin Metropolis in Nigeria, through the supply authority. The adequacy of the obtained results was determined by comparing experimental values with America Society for Testing and British Standard (BTA4705) pre-requisites. About seventy five percent (75%) of the tested samples failed at least one of the tests, indicating inadequacy in the routine checks. Economic impacts of the obtained results and major causes and prevention of insulation oil degradation were also presented.
Human Body Resistance and Temperature Measurement Device
Authors: Wara S.T. , Oghogho I. , Abayomi-Alli A. , Odikayor C.D. , Essien M.S.
Published: March 2009

This paper discusses the design and construction of a human body resistance and temperature measurement device. The device measures the human body temperature and resistance when the sensing probes are placed in contact with the human skin. The design analysis was based on simple electronic circuit theories leading to specification and choice of components used for the construction of the system. After the construction and testing with various individuals the human body resistance and temperature was found to be within the ranges of 1KΩ to 210KΩ and 36.10C to 37.50C respectively. The paper discuses the various effect of current on the human body and their implication. The system can be adapted to various fields such as bio-technology, security (lie detector), safety equipment in industries and companies to determine insulation.
The Quality of Concrete Made with Typical Benin City Silty Sand
Authors: Alutu O.E. , Ejike E.N.
Published: March 2009

The purpose of this study is to carry out tests on concrete made with a typical Benin City silty sand and determine the major concrete quality indicators such as pulse velocity, water/cement ratio and compressive strength in order to justify the continued utilization of such sands in concrete production in and around Benin City. To do this, concrete made with the selected sand were designed using DOE mix design method and test cubes were cast in three batches. Two cubes were cast for each of the sixteen consecutive tests carried out and averages taken for each design grade strength of 10,20,30,40 and 50N/mm2. Also, pulse velocity and rebound hammer tests were carried out on the cubes before testing the cubes destructively. The results show that concrete produced with the Benin City silty sands are of good quality in all respect but generally characterized by low 28th day – characteristic strength. The sands should therefore be used in construction provided that the mean strength aimed at during design is sufficiently higher than the characteristic strength by the strength margin (ks) from structural point of view to enable every part of the structure have adequate strength.
An Experimental Autonomous Path Tracking Mobile Robot
Authors: Senanayake Hasitha M. B. , Akinsanmi Olaitan , Mu’azu Muhammed Bashir
Published: March 2009

Autonomous Vehicular Navigation poses interesting challenges and, Automatically Guided Vehicle (AGV) Path Tracking presents an important notion in real-time Mechatronics applications. This paper describes the design of a Path Tracking Automatically Guided Vehicle that is capable of autonomously navigating a predefined path on a level navigating plane and, the designed AGV successfully completed a 3.42 meter test course in precisely 2 minutes 16 seconds. The AGV comprises a PIC16F84A microcontroller utilized as an embedded controller and, an array of Infrared reflective optical sensors to enable path detection and tracking. Among the primary objectives of the design that were achieved was to design the low-cost mobile robot from component parts sourced locally, from within Nigeria.
Leaching of Trace Metals from Two Different Size Soils
Authors: Abdulfatah A.Y. , El-Hamalawi A. , Wheatley A.D.
Published: March 2009

Two different size-grained soils were subjected to column experiments with a hydraulic loading representing two years’ rainfall. Leachates were collected and analysed for pH and temperature and for eight trace metals, namely; Iron (Fe), Copper (Cu), Chromium (Cr), Nickel (Ni), Lead (Pb), Manganese (Mn), Zinc (Zn), and Silica (Si). The analysis was conducted using an inductively coupled plasma (ICP) method of spectrometry. The results show different extractable metal concentrations from the two soil samples.
Development and Performance Evaluation of Rainwater Harvester for Drip Irrigation of Juvenile Citrus Orchard
Authors: Afolayan S.O. , Ogedengbe K. , Adeoye I.B. , Olufunmi O.O. , Ajetunmobi T.
Published: March 2009

Water crisis is assuming a more explosive and dangerous phenomenon due to stiff competition and demand between domestic use and agricultural activities. Farmer friendly and affordable indigenous water harvesting structure was developed and evaluated for the Farming systems research citrus expansion orchard at the National Horticultural Research Institute, Ibadan. The structure, made of bamboo materials and polyethylene sheets was constructed to harvest rainstorm and stored in plastic reservoirs between September and October 2007. The aim was to apply the water for drip irrigation of young citrus seedlings during the dry months of November until the on-set of rainfall. Six thousand litres of water were harvested. Drip irrigation system was connected to the rainstorm harvester to facilitate application of water to the young citrus seedlings planted at 7m by 5m spacing. Water application at the drip rate of 2.4 l/hr was done in split-plot fitted into randomized complete block design at one, twice and thrice per week with three replications under four fertilizer sources (poultry, horse, cow manures and urea fertilizer). Base line growth data for citrus at the initial watering stage stands at 139 for number of leaves, 83.5 cm for plant height, and 12.3 mm for stem diameter. Watering thrice per week under poultry manure was found to produce the best growth parameters. Generally, the structure was discovered to be cost effective, water saving, adoptable and affordable by farmers with little or no maintenance or educational background.
Flapper Feed Device for Improved Productivity of Cassava Grater
Authors: Okoli John U. , Aadum A.
Published: March 2009

A modified hopper design of the conventional cassava grater and its concomitant productivity improvement is presented. One of the sides of the inverted truncated rectangular pyramidal hopper was hinged at the lower end and swung through angle of 15 to 30 degrees. This flapper swing served as feed for the rotary grater. The flapper allowed the cassava tubers to be fed over a larger grater surface area permitting cassava feed over an angle of 120 degrees instead of the usual 90 degrees. It further allowed the variation of the space between the rotary grater and the hopper thereby enhancing complete maceration of the tubers. The presence of ungrated cassava chips in the macerated mash common feature with conventional graters was reduced to negligible proportions. A process improvement of up to 100 per cent in thru-put was obtained compared with the conventional graters.
Methods of Preserving and Improving the Quality of Locust Beans
Authors: Ogunleye I.O. , Awogbemi O.
Published: March 2009

This research work presents two methods of preserving and improving the quality of locust beans namely: salting and drying. 80g of non-salted sample of locust beans and the same quantity of the sample with 5g of salt and 10g salt were subjected to direct sunlight drying for 5 days. Proximate analysis showed that dried salted sample contains 67.65% of protein while dried non-salted sample has 66.82% of protein. The non-salted sample has a microbial load of 1.02×107cfu/g while the salted sample has 1.42×105cfu/g at the end of the fifth day of drying. The non-salted has the greatest drying rate while the 10g salted sample has the least drying rate.
Variations in Certain Climatic Parameters and Implications for Agricultural Production in Makurdi (Benue State), Nigeria
Authors: Isikwue M.O. , Onoja S.B. , Isikwue B.C.
Published: March 2009

This work studied variations in certain climatic parameters, specifically precipitation, soil moisture and outgoing Long wave radiation (OLR) from the earth from 1997 to 2006 in Makurdi, Nigeria. Results showed that precipitation rate in Makurdi deviated from the normal annual bimodal pattern of precipitation in Nigeria. Precipitation was highest in August/September throughout the study period. The dependent of soil moisture on precipitation is highly significant as shown by the high positive value (81%) of R2. Soil moisture content also varied similarly while OLR varied inversely. The effects of the variations of these parameters on agricultural production are highlighted.
The Influence of Vibration Time and Sand Type on the Compressive Strength of Sandcrete Hollow Blocks
Authors: Alutu O.E. , Omorogie A.
Published: March 2009

The purpose of this study is to see if varying the vibration time and sand type during moulding of blocks would affect the strength of the blocks. To this end, seven types of sands: Okhuahie and Ovia river sands; Okhuahie, Ovia, Ikpoba flood and Okhoro erosion sands were collected for the study. A total of 315 blocks each in 150mm and 225mm sizes with cement to sand ratios of 1:6 were made using the seven brands of sand. The blocks were vibrated for 10, 15, 20, 25, and 30 seconds and tested for compressive strength at 7 days, 14 days and 28 days respectively. The result showed that the relationship between compressive strength of the blocks and the vibration time for various sand types was linear up to vibration time of 30 secs. The sand type also influenced the strength of the blocks as Okhuahie river sand gave the highest compressive strength followed by Ovia river sand and the least was Okhoro erosion sand. At least 52% increase in compressive strength of 150mm and 225mm sandcrete blocks were achieved by raising the vibration time from 15 seconds to 25 seconds in the seven types of sand and 100% increase was achieved by raising the vibration time from 15 to 30 seconds.
Methods of Estimating Runoff and Soil Loss in Plots under Different Plant Densities of Amaranthus
Authors: Okoli C.S.
Published: March 2009

This paper reports of study that was conducted to evaluate runoff rates and sediment yield as affected by different plant densities of amaranthus at the experimental farm of Agricultural Engineering Department, Federal University of Technology, Akure, Ondo State, Nigeria. The experimentally based study is aimed at determining the runoff and sediment yield relationship as affected by different plant densities of amaranthus at the experimental farm. Treatment were based on four plant densities A (97 plant/m2) B (42 plant/m2) C (125 plant/m2) D (69 plant/m2), runoff depths and sediment yields were measured during the months of August to November 2003. A complete randomized block design was used to evaluate treatment methods on the basis of sediment yield and run off depth. A rainfall-Runoff model was established to enable future occurrence to be predicted. The water balance equation was used to compute the evapotransipiration (ET) for each plot. There were significant differences in sediment yields and run off depths among the treatments at 5% level of significance treatment. A (97 plant/m2) and C (125 plant/m2) were found to have the least amount of runoff and sediment yield, while treatment B (42 plant/m2) and D(69 plants/m2) had the highest amount of runoff and sediment yield. The result confirms the proposition that increased plant densities had a significant effect in reducing runoff and sediment for agricultural lands.
Application of Enterprise Modelling (EM) Principles to Improving the Performance of a Semi-Automated Production System
Authors: Ajaefobi J.O. , Weston R.H.
Published: March 2009

To cope with high levels of complexity, competition and change requirements, manufacturing enterprises (MEs) need to continuously improve their process and resource system performances. Enterprise Modelling (EM) is considered a prerequisite for enterprise integration and performance improvement because it can be used to capture relatively enduring knowledge about any specific business environment in which production systems will be deployed. With this prerequisite in mind, EM principles were deployed to capture and develop ‘static’ models of an SME. This provided detailed descriptions of enterprise production operations and their precedence relationships. A discrete event simulation tool was then used to develop time dependent ‘dynamic’ models of selected process segments of the specific case Enterprise Model. This allowed the computer execution of alternative production system designs to be assessed under SME specific changing scenarios and enabled suggestions for potential improvements to be made.
Rolling Temperature for Steel Hot Flat Rolled at Low Strain Rates
Authors: Aiyedun P.O. , Aliu S.A.
Published: March 2009

Different methods of obtaining averages have been used to determine mean rolling temperatures from measured temperatures of various specimens during roll contact in hot flat rolling. The obtained mean rolling temperatures were used in turn in hot rolling simulation programs based on Sims, and Bland and Ford’s theories for calculating rolling loads and torque during hot flat rolling of steels at low strain rates (0.08 – 1.5 s-1). The hot rolling Bland and Ford’s (HRBF) Theory and Sim’s Theory gave similar results when any of the averaging methods of temperature is used to calculate rolling load and torque at high strain rates (1.5 –500s-1). However at low strain rates HRBF gave closer approximations to experimental results. Comparing the results with experimental values, the harmonic mean was found to give the best mean rolling temperature for hot flat rolling simulation at low strain rates compared to geometric mean, arithmetic mean and root mean square.
Network Structures, Flexibility and Stability in Thermal and Chemical Environments of Polyurethane Prepared from Rubber Seed Oil.
Authors: Okieimen F.E. , Bakare I.O. , Pavithran C.
Published: March 2009

Rubber seed oil monoglyceride was prepared by glycerolysis and characterized by chemical and spectroscopic methods. The monoglyceride was reacted with excess diisocyanates (hexamethylene -diisocyanate and toluene diisocyanate), and the network structures and molecular mass of the polyurethane were determined from swelling experiments in toluene and size exclusion chromatography respectively. The polyurethane films obtained were characterized in terms of their resistance to chemicals (water, brine, dilute acid and alkali) thermal stability and tensile and flexural strength and modulus. It was found that under the experimental conditions, conversion of the triglyceride content of the rubber seed oil to monoglyceride not quantitative less than 70%. The measured properties of the RSO-based polyurethanes were attributed to the degree of crosslinking and the observed superior properties of the polyurethane obtained with hexamethylene diisocyanate in comparison with polyurethane obtained with toluene diisocyanate were explained in terms of structure-property relationship. The measured properties of RSO-based polyurethanes compare favourably with the properties reported for polyurethanes derived from other vegetable oils.
Studies in the Utilization of Biobased Additives as Thermal Stabilizer for Plasticized PVC
Authors: Okieimen F.E. , Egbuchunam T.O. , Balköse D.B.
Published: March 2009

Divalent metal (barium, cadmium, calcium and zinc) soaps of rubber seed oil and their binary mixtures (Ba/Cd and Ca/Zn) and epoxidized rubber seed oil (4.5% epoxide content) and its admixtures with the single divalent metal soaps were evaluated as thermal stabilizer for dioctylphthalate plasticized PVC using changes in discolouration indices (yellowness index and UV absorption at 360nm) and initial rates of dehydrochlorination measured at 140 and 160oC. The results obtained showed that the divalent metal soaps were relatively effective in stabilizing the dioctylphthalate plasticized PVC against thermal degradation and that the binary soap mixtures enhanced the heat stabilizing effectiveness: marked reduction in the values of the discolouration indices; longer dehydrochlorination induction period and smaller values of rate constant of initial rate of dehydrochlorination. It was found that epoxidized rubber seed oil was less effective in comparison with the divalent metal soaps in stabilizing plasticized PVC against thermal degradation. These results show that the bio-based additives are compatible with dioctylphthalate plasticized PVC, stable to heat within the range of temperature used in the processing of plasticized PVC, inhibit/retard dehydrochlorination and reduce the extent of degradation.
Effect of Base Material on the Pore Size Distribution and Surface Area of Activated Carbon
Authors: Ojo O.O.
Published: March 2009

Powdered activated carbons were produced from palm kernel shells, corn cobs and cow bones by carbonization, pulverization and activation. The resulting granule has a surface area of 430.04 m2/g, 4022.15 m2/g and 733.60 m2/g respectively with controlled pore size. The characterized surface area enables the carbon to absorb vapors from gases, and substances from liquids. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity. The surface properties are function of the base materials used in the preparation. Determinations of their adsorptive capacities show that activated carbon prepared from corn cobs has the highest adsorptive capacity.
Effect of Lubrication Additives on the Physical and Chemical Properties of Soyabean Oil
Authors: Aluyor E.O. , Audu T.O.K.
Published: March 2009

The effect of two lubrication additives on the physical and chemical properties of refined soybean oil was studied. The two additives used were a complex blend of anti-oxidant; anti-wear and pour-point depressant-AP821 and AP820- used in the production of Super v and Visco 2000 brands of lubricants respectively. The physical and chemical properties of the soybean oil and base oil samples containing varying percent by volume of each additive were analysed. Results obtained show that the flashpoint of soybean oil increased from 256.6oC to 265oC and 284oC for the AP821 and AP820 additives respectively. This was better than the increase recorded for the base oil which increased from 208oC to 215 oC and 228oC for the AP821 and AP820 additives respectively. Other results obtained for pour point reduction, specific gravity and viscosity showed a positive effect of the additives on soybean oil.
Effect of Pass Reduction on Rolling Parameters Using Reverse Sandwich Model Integrated into the Hot Rolling Bland and Ford’s Theory
Authors: Alamu O.J. , Aiyedun P.O. , Adekunle Nurudeen O.
Published: March 2009

Hot flat rolling simulation by use of the Bland and Ford’s cold rolling (HRBF) theory confirmed the reverse sandwich effect in selected carbon steels at low strain rates. The Reverse Sandwich Model (RSM) was subsequently integrated into the HRBF theory for load and torque estimation. In this work, the effect of pass reduction on rolling temperature distribution, yield stresses and rolling load were studied for AISI Type 316 stainless steel (HCSS316). For this new simulation, at low and high strain rates, results showed that the ratio of experimental to calculated roll load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HCSS316 at low reductions. This is in agreement with results obtained using Sim’s theory, HRBF theory and the RSM.
The Dependence on Temperature of Carbonization and Chemical Activation on Characteristics of Granular Activated Carbon Characteristics
Authors: Okieimen C.O. , Ogbeide S.E.
Published: March 2009

Nigeria imports large quantities of activated carbon annually for local use. In this study the development of low cost and effective adsorbent from the palm kernel shell for the treatment of waste water is examined.Palm kernel shells were used to produce activated carbon by carbonization at different temperatures (500 -10000C) and by chemical activation using 1M citric acid and saturated ammonium chloride as activated agents. The optimum temperature of carbonisation was found to be 950oC, the activated carbons produced were characterized. The measured characteristics: yield, pH, bulk density, surface area, porosity, resistance to mechanical abrasion and total surface charge of the activated carbon prepared from palm kernel shell were 18.6%, 7.8, 0.636g/ml, 112.09mgl2/gC, 19.23%, 2.36molH+/gC respectively, for citric acid activated carbon . For ammonium chloride activated carbon they were determined to be 17.50%, 8.55, 0.716g/ml, 109.69mgl2/gC, 19.76% and 2.06, 2.36molH+/gC respectively. The experimental results showed the possibility for the production of activated carbon with well developed pore structure, surface, and bulk density high mechanical abrasion and reasonable total surface charge.
Effects of Preservative Agents on Cassava Starch Adhesives
Authors: Akhabue C.E. , Ebewele R.O. , Oyedoh E.A.
Published: March 2009

This research seeks to explain the effects of various preservative agents on starch adhesives. Adhesives were produced from cassava starch by gelatinizing with sodium hydroxide and heat. Modifications and addition of preservative agents to these adhesives were done in order to obtain a suitable working consistency and also to prolong their shelf life. Starch adhesives formed by gelatinizing with sodium hydroxide possesses good working properties, but requires mild alkalinity (pH 9.60). The stability of the final adhesives produced was also found to be dependent on the pH. At pH 9.60, the percentage decrease of viscosity after 18 days was 69.6%, while at pH 3.2, it was 98.85%. The shelf life was also controlled by adding various preservative agents to the adhesives pastes. The preservative agents added were formaldehyde, benzoate and butraldehyde. The addition of 2g of these preservative agents per 100g adhesives reduced the percentage decrease of viscosity by as much as 40% compared to that when preservative agents were not added.
Maximizing Generated Energy Usage through Combined Cycle Cogeneration
Authors: Enyi C.G. , Appah D.
Published: March 2009

Case studies from two Nigerian hydrocarbon processing industries, where gas turbine generators (GTG) were used for power generation were analyzed. The first study analyzed a simple cycle power generation where the GTG produced 25 MW of electricity and three separately fired boilers produced the required process steam. The second study analyzed a combined cycle (cogeneration) where the same GTG that produced 25 MW of electricity also generated 90700 Kg/hr of steam from the turbine exhaust gas. The study shows that cogeneration (combined cycle) satisfied all the electric power and steam requirements of the plant. Simple cycle only satisfied the electric power requirement. Other disadvantages of simple cycle show that over 60% of the generated energy is lost to the environment in form of heat. A loss in production worth over $6,182,400 as a result of failure in a separately fired boiler was calculated. The study concludes that cogeneration must be undertaken with an awareness of energy system expansion, generation costs and the need for industrial energy consumption of a given plant.
Pressure Derivative Behavior of Two-Layered Reservoir with Vertical Wells
Authors: Akhipemelo D. , Adewole E. Steve
Published: March 2009

Layered reservoir systems present a huge challenge to both reservoir and production engineers, because of difficulty encountered in reservoir management and well completions. In this paper, the solution to a 2D reservoir model is utilized to study pressure and pressure derivatives of a two-layered crossflow reservoir with a vertical well. No skin and wellbore effects are included. The interlayer fluid transmissibility ratio is varied for the same layers properties, to study the effects of layers heterogeneity and well completion choice on flow performance. Results show that decreasing values of specific transmissibility ratio, , signifies completion in the more permeable layer, a shift in the pressure response to the left and a short transition period to depletion of the second layer. Furthermore, increasing values  means that the well is completed in the lower permeability layer causing delay in the depletion of the second layer as a result of long transition period.
Geoinformation for Oil Spill Disaster Management in the Niger Delta Region of Nigeria
Authors: Audu Henry A.P. , Ehiorobo J.O.
Published: March 2009

One of the major ecological and environmental problems confronting the Niger Delta region of Nigeria today is degradation and hazard arising from oil spill. Spillage occurs in this region either from vandalisation or sabotage by ethnic militants, youths who are jobless and therefore deliberately break open crude oil transport pipelines to scoop fuel for sale in the black market to earn a living or rupture of pipes due to ageing and mechanical malfunction. In most spillages, farmlands are lost, aquatic and wildlife is affected, and people are in many cases displaced from their homes. In extreme cases as occurred in Jesse, lives were lost. This paper examines the use of Geoinformation technology in oil spill response modelling and management. The use Global Positioning System (GPS) derived data for the creation of a management database is discussed. Data generated from the Jesse spill and fire site covering these areas were used to generate case study scenario for oil spill response modelling and clean up management operation.
Developing a Managed Pressure Drilling Strategy for Casing Drilling Operations
Authors: Oyeneyin Babs Mufutau , Kelessidis V.C. , Bandelis G. , Dalamarinis P.
Published: March 2009

Casing drilling can be an effective method of reducing drilling costs and minimising drilling problems but its uptake around the world has been slow with only a few wells drilled so far with casing. Complex geological features like the high overburden on top of shallow unconsolidated reservoirs characteristic of offshore West Africa can benefit from casing drilling when effectively combined with Managed Pressure Drilling technique. For the industry to develop a managed pressure drilling capability that will allow today’s generation of complex wells to be drilled safely with casing, it is necessary to develop models that include the effect of eccentricity , rotation and fluid rheology at bottom hole conditions on flow and pressure regimes, and to embed these models within an easy to use, intuitive well design package for pre planning and as a real time tool to monitor and provide forward simulations based on real time rig and downhole data. The paper presents new results of the theoretical predictions of the wellbore pressure regimes incurred when different types of drilling fluid flows in concentric and eccentric horizontal annuli. The concentric and eccentric casing drilling results are compared with parallel predictions from conventional drillstring results from developed analytical solutions integrated into the VisWELL(DeskTop Simulator) , which is used in simulating well operations.
The Role of Renewable Energy in the Electricity Industry in Zimbabwe
Authors: Mbohwa C. , Siso Bukhosi
Published: March 2009

Zimbabwe has an abundance of the renewable energy sources yet it is facing chronic energy and capacity shortages, leading to the country relying on imported power, having load shedding and having blackouts. This paper discusses the renewable energy power potential, the role renewable energy resources can play to alleviate these problems and the policy options and instruments that can be used to promote renewable energy technologies. The study found out that Renewable Energy Technologies are cost-competitive to conventional energy sources in several applications. The major barriers to the deployment of the technologies are discussed and possible solutions proposed.
Analysis of Fish Fillet Drying Rates under Three Solar Energy Drying Systems
Authors: Mwithiga Gikuru , Mwangi Samuel Gathuki
Published: March 2009

A small Box type solar dryer with controllable air inlet was designed and tested. The dryer had a mild steel absorber plate and a polyvinyl chloride (pvc) transparent cover and could be adjusted to allow variation in airflow rate through the drying chamber. A convectional green house covered with transparent pvc and into which a drying tray stand at a height of 90 cm above the ground was placed made up the second drying method. The rate of air flow through the green house could be controlled by adjusting the opening at either end of the tunnel. The third method of drying which also served as the control is sun drying in which case the drying trays was placed 90 cm above the ground but left unenclosed to allow free flow of ambient air. The air temperature at points just above the drying rack was monitored for all three drying systems under no load conditions from morning to late afternoon. The temperature was also monitored during drying when the trays were loaded with fish of different fillet thicknesses. The rate of loss of moisture was also monitored by weighing the fillets at regular interval until the moisture dropped to 20%, dry basis or lower. The average temperature inside the plenum chamber of the box type solar dryer was found to have a high daily value of 71.1OC although an absolute maximum value of 74.4OC was recorded. This maximum value could be reached on cloudless days between the hours of 13:00 and 1400. The green house recorded a slightly lower average temperature and its peak value occurred latter in the day. Both the green house and the box-type solar dryer had average drying chamber temperatures that were more than 30 centigrade degrees above ambient conditions. Both the box-type and green house type solar dryer could dry thin slices of fish fillet in 1-3 days as opposed to the 7-9 days normally required under sun drying conditions. The quality of the dry fillet was satisfactory and CIE LAB colour values did not change significantly during drying.
Power Quality Assessment in a Distribution Network
Authors: Adegboye B.A.
Published: March 2009

The paper explores power quality disturbances on a specified section of the distribution network of a Textile Industry in Kaduna State of Nigeria. The 33kV PHCN incoming to the industry is stepped down to 11kV by a 7.5MVA, 33/11kV three-phase transformer. This transformer supplies various 11/.415kV transformers present in the distribution network. Another 11kV PHCN incoming is used in event of any failure from the 33/11kV transformer. The paper focuses on Transformer No. 1, a 150kVA, 11/.415kV three-phase transformer operating at 0.9 power factor, located at printing and dying (P/D) building 1. Majority of the loads on it are inductive. Measurements were taken at the secondary terminal of this transformer by the use of the Harmonitor 3000 power analyzer, which generates the voltage and current waveforms, power factor, voltage and current total harmonic distortion and the apparent power of the red, yellow and blue phases of the transformer. Analyses of these data reveal the disturbances due to harmonics in the phases and neutral of the transformer. The effect of the harmonic current is seen as poor power factor of the transformer. Considering the observations and analyses of the power quality of the transformer 1 (P/D), the paper proposes some recommendations for improving the power quality of the distribution network under study.
Optimal Utilization of Solar Arrays: Design and Implimentation of a Motorised Solar Energy Photovoltaic Array System
Authors: Ubeku E.U. , Igbinovia S.O.
Published: March 2009

In this paper a motorized solar energy collector system-a driver system that positioned the solar cell panel differently during day-time was design and implemented. The aim is to optimize the amount of solar energy that can be trapped from the sun using a solar cell panel. This is achieved by using a stepper motor, controlled by Atmel AT89C52 microcontroller, to align the panel such that all incident rays strike normal to the panel’s surface thereby maximizing the amount of solar energy that can be trapped from the sun. The alignment is time dependant. This model was implemented and tested and the results proved to be successful in maximizing the energy received from the sun than if the solar panel was fixed at a particular position.