bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on Formation Mechanism of Cu/Cr-Al2O3 Nanocomposite
Authors: Sheibani Saeed , Ataie Abolghasem , Heshmati-Manesh Saeed , Martínez Alfonso Caballero
Published: October 2011

In this research, formation mechanism of a Cu/10 wt.% Cr-10 wt.% Al2O3 nanocomposite via mechanical alloying and subsequent heat treatment has been investigated. It was found that during milling process, Cu (Al) solid solution and Cu9Al4 phase were formed as intermediate products. Further heat treatment carried out under argon atmosphere at 900°C for 8 hours resulted in completion of Cr2O3 reduction by Al. The mechanism of in-situ formation of Al2O3 reinforcement in the copper matrix was also discussed as a two stages process. The SEM and TEM results confirmed the proposed mechanism and showed that the Cr dispersoids surrounded by Al2O3, in the nanometric scale. Also, the Cu matrix with mean crystallite size of 30 nm was stable at high temperature.
Quantitative Structure-Activity Relationship Study of Radical Scavenging Peptides Based on Orac Method by Using Different Sets of Amino Acids Descriptor
Authors: Li Yao Wang , Li Bo
Published: October 2011

Some radical scavenging peptides by ORAC method from different hydrolysates were used for the quantitative structure-activity relationships (QSAR) research. Partial least-squares regression analysis (PLSR) was treated as the method to build the model with 17 kinds of amino acid descriptors. In order to translate the sequence to the same length, two-terminal position numbering (TTPN) was applied. Two of amino acid descriptors VSHE and VSW were selected for their excellent performance (R2, Q2, and RMSEcwith VHSE and VSW descriptor are 0.995, 0.630, 0.318 and 0.966, 0.543, 0.181 respectively). VHSE has the definite physicochemical meanings and easy to understand while VSW has good predictive ability (Rand RMSEpwith VHSE and VSW are 0.404, 2.633 and 0.635, 2.298 respectively). It is believed that the position No.2 amino acid from N-terminal (N2) have more importance than others in sequence, and most of electronic properties are negative to activity while all the steric properties are positive to activity as well as the hydrophobic properties. The suitable amino acids in sequence are as follow: G, R, K, W, Y, N, E, H, and Q are suitable for N2position which illustrated the importance of acidic amino acids in peptide sequence for radical scavenging activity.
Classification of Fine Recycled Aggregate Used in Asphalt Concrete
Authors: Sun Yi Han , Wu Shao Peng , Zhu Ji Qing , Zhong Jin Jun
Published: October 2011

Two classification methods for fine recycled aggregate used in asphalt concrete were investigated in this paper, respectively classifying by fine recycled aggregate properties and asphalt concrete properties. When classifying by fine recycled aggregate properties, all test results of fine recycled aggregate properties can meet the technical requirements of China with obvious differences in quality. When classifying by asphalt concrete properties, fine recycled and natural aggregate was respectively used to prepare asphalt concrete with the same gradation, the same asphalt, the same limestone mineral filler and the same coarse natural aggregate. Some related properties of asphalt concrete were discussed to classify fine recycled aggregate. It is proposed in this paper that fine recycled aggregate should be classified into three types by asphalt concrete properties and the proposed classification criterion is given.
Texture Analysis of Turned Surface Images Using Grey Level Co-Occurrence Technique
Authors: Datta Anurup , Dutta Samik , Pal Surjya K. , Sen Ranjan , Mukhopadhyay Sudipta
Published: October 2011

The main purpose of this work was to study the applicability of an image texture analysis method, namely, the grey level co-occurrence matrix (GLCM) method for the examination of the smoothness of the images of a turned surface. The effect of the variation of the pixel pair spacing (pps) on the construction of the GLCM was also considered and then, contrast and homogeneity were calculated from the GLCMs which served as texture descriptors for the quality of the machined surface. Finally, the variation of these texture descriptors with cutting time was analyzed and compared with the variation of tool wear and surface roughness with cutting time.
Inactivation of Algae with Multi-Needle Gas-Liquid Hybrid Discharge Reactor by Introducing Oxygen and Air
Authors: Aye Nyein Nyein , Sun Bing , Zhu Xiao Mei , Gao Zhi Ying , Song Yan Jing , Sato Masayuki
Published: October 2011

In this paper, certain investigations were performed in the following aspects: analysis of optical emission spectra which is used for the identification of ˙OH, ˙H, ˙O, H2O2and O3on the inactivation of algae by observing the gas and liquid phase compositions, the optimal parameters such as treatment time, pulse peak voltage, and pulse frequency. Each experiment was carried out by introducing two difference gases, oxygen or air, separately above the liquid in the reactor. The results showed that the inactivation rate of algae reached 100% in the case of oxygen bubbling into the Chlorella spp. contaminated water for 7 min and the Chrysophyta spp. for 5 min. It took much longer time in the case of air bubbling that took 10 min for Chlorella spp. and 7 min for Chrysophyta spp.
Design of a Portable Bioelectrical Impedance Measurement System
Authors: Lu Yi , Huo Cheng Yu , He Ai Jun
Published: October 2011

Bioelectrical impedance measurement is a widely used biomedical detecting technology. However, most traditional bioelectrical impedance measurement devices are bulky, expensive and lack of flexibility. In order to reduce costs, increase flexibility and maintain similar performance, a portable bioelectrical impedance measurement system was designed in this paper. The measurement front, with an ARM based microcontroller and integrated impedance converter chip as its core device, communicated with the host computer via USB bus. Based on the four-electrode technique, DFT digital demodulation and software calibration and compensation algorithm, the system realized its functions. Experimental results indicate that the system can achieve high precision bioelectrical impedance measurement. With the advantage of high integration and low-cost, the system can be widely used in household healthcare, clinics and biomedical research and testing.
Fault Diagnosis of Offshore Platforms Using the Local Mean Decomposition Method
Authors: Lin Jin Shan
Published: October 2011

Traditional techniques are not suitable for exploring non-stationary and nonlinear signals. Although empirical mode decomposition (EMD) is a powerful tool for the non-stationary and nonlinear signal analysis, yet it still has some shortcomings. Local mean decomposition (LMD), a novel signal processing method, seemingly overcomes many deficiencies of the EMD method and can take place of the EMD method for analyzing non-stationary and nonlinear signals. In this paper, the LMD method is employed to examine the signal captured from the decks of the WZ12-1 platform and succeeds in displaying the reasons causing the excessive vibration of the WZ12-1 platform. The results suggest that the LMD method seems to be a feasible method for fault diagnosis of offshore platforms.
Near-Infrared Quantum Cutting Nanophosphors for Solar Cells
Authors: Li Su Wen
Published: October 2011

An efficient near-infrared (NIR) quantum cutting (QC) nanophospors with Ce3+, Yb3+ codoped in CaF2 had been synthesized by hydrothermal method and characterized by X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, photoluminescence spectra and decay dynamics. The nanoparticles were uniform and monodisperse. Under the excitation of 5d level of Ce3+, an intense NIR emission at 900-1050nm was observed which match to the energy of Si band gap of Si - based solar cells. In the Ce3+, Yb3+ codoped CaF2, the lifetime of Ce3+ decreases Superscript textand the quantum efficiency (QE) increases with increasing Yb3+ concentration.
Application of Matlab Optimization Tool Box on Sections of Prestressed Steel-Concrete Composite Box Girder
Authors: Wang Jun , Yan Wen , Gui Xue
Published: October 2011

The constrained optimization is one kind of mathematics programming, which was widely adopted in the engineering. The efficiency optimization was achieved in the Using MATLAB optimization toolbox .Numerical result illustrated that the optimization mathematical model of optimization was exact and the algorithm effective. The method can be mastered by the engineers and widely used in the engineering design .
The Effects of the Process Parameters on Micro-Hardness for Electroless Ni-P-Nano SiC Composite Plating
Authors: Wang Hong
Published: October 2011

The orthogonal test method has been used to study the effects of the concentration of SiC, the speed of mixing, the temperature and the surfactants on micro-hardness, and obtained the optimized technological scheme and fine Ni-P-SiC composite coating. The results showed that using citric acid-acetic acid as complexing agents can obtain high speed of depositing and homogeneous coating with SiC well-distributed. Among the technological parameters, the effects of the concentration of SiC particles on micro-hardness is biggest, and the surfactants is next. Give consideration to depositing rate and stability of the liquid, the temperature should be controlled at 82±2°C, the concentration of SiC particles and surfactants should be controlled in 4g/L and 60mg/L.
Complex Generalized Basis Reduction Assisted Successive Interference Cancellation Detection for SCBLAST Systems
Authors: Ni Liang Fang , Li Qing Qing , Du Si Dan
Published: October 2011

Complex generalized basis reduction assisted successive interference cancellation is proposed for mitigating multi-stream interference of transmitted signals in single code Bell Laboratories layered space-time systems. Generalized basis reduction method is modified to better the complex channel matrix, which leads to the extended generalized reduction basis channel matrix with shorter and roughly orthogonal basis vectors in polynomial-time. This distinguished property guarantees the concatenated successive interference cancellation detector, based on the MMSE criterion, converges to the approximately global optimum estimation points. Emulation results have shown that the proposed detection scheme is superior to other suboptimum detection schemes considered in this paper in terms of two points. They are the mitigation of multi-stream interference and the diversity gain. Its performance is close to the sphere decoder but with a lower complexity.
Experimental Study on the EFI Engine Fueled with LPG
Authors: Li Xin Guang , Wang Yin Yan , He Qing Lin , Zhang Ai Guo
Published: October 2011

The experimental system was established in order to study the dynamic and economic performance of vehicle engine fuelled with LPG. Based on the experimental system, the variable experimental study including engine power, torque and consumption rate were carried out. The l results showed that with the rise of the engine rotational speed, power and torque of the engine fueled with LPG increased first and then decreased, but all of them were lower than that of the 93#gasoline. The consumption rate of the LPG was better than the 93#gasoline for the engine case at 2000r/min and 4000r/min on the energy consumption rate.
Skin Color Detection Method Based on Direct Least Square Ellipse Fitting in CrCbCg Space
Authors: Sun Jin Guang , Zhou Yu Cheng
Published: October 2011

Skin color detection is an important in computer vision.This work presents a new efficient method for skin color detection based on an improved direct least square ellipse fitting in the space CrCbCg. The color distribution statistics of three-dimensional CrCbCg is obtained by fitting the color distribution ellipse boundary in the Cr-Cb, Cr-Cg, Cb-Cg plane exactly ,finally ,the criteria based on the statistics is used to detect skin color area accurately. Experimental results show that this method improves the robustness of the skin color detection to complex environment.
Dynamic Mechanical Properties and Thermal Stability of PTT/POE/OMMT Nanocomposites
Authors: Run Ming Tao , Li Na , Xing Bing Tao , Yao Meng , Zhou Wen
Published: October 2011

The dynamic mechanical properties, phase morphology and thermal stability of the poly(trimethylene terephthalate)/maleinized poly(octene-ethylene)/organo-montmorillonite nanocomposites (PTT/POE/OMMT) were investigated by using the thermodynamic mechanical analyzer (DMA), transmission electron microscopy (TEM) and thermal gravimetric analyzer (TGA), respectively. The results suggest that the modulus of elasticity of the PTT/POE/OMMT nanocomposite increases, and the glass transition temperature first slightly decreases and then increases with increasing OMMT content because that the TPP plays the role of plasticizer and OMMT plays the role of reinforcing agent. OMMT disperse evenly in the polymer matrix with most of the strip-like sheet morphology. The addition of the OMMT does not apparently affect the thermal stability of the PTT/POE/OMMT nanocomposite.
Rheology, Morphology and Mechanical Properties of PA6/PP-g-MAH/POE Blends
Authors: Run Ming Tao , Yao Meng , Xing Bing Tao , Zhou Wen
Published: October 2011

The rheology, morphology and mechanical properties of the PA6/PP-g-MAH/POE blends prepared by twin-screw extruder were studied by rheometer, scanning electron microscopy, universal tester and impact tester, respectively. The results suggest that the impact strength is improved by the POE acting as a toughening agent, while the compatibility of PA6 and POE is improved by the compatibilizer of PP-g-MAH. Furthermore, the PP-g-MAH component also acts as a reinforcing agent for decreasing the strength depression induced by the POE component. When POE content is about 9 wt% and PP-g-MAH content is about 10% in blends, the blend has the maximum tensile strength and impact strength. All melts of PA6/PP-g-MAH/POE blends are pseudo-plastic fluids. Both the POE and PP-g-MAH components can increase the apparent viscosity of the melt due to their facility of the linear molecular.
X Ray Phase Contrast Imaging for the Extreme Low Density or Weak Absorption Materials
Authors: Wu Jie , Chen Jia Bi , Zhang Xue Long
Published: October 2011

In order to get better images from the extreme low density or weak absorption materials, a new modulation transfer function model is established for the X ray phase contrast imaging. Then the parameter effects of ray source size are elaborated on the basis of the partially coherent optical theory. From the simulation and calculation, the proposal and parameter optimization are revealed according to the actual materials experiment conditions.
The Impact of Heat Treatment on Pyrophyllite Structure and Acid-Soluble Properties
Authors: Wu Jun Jun , Chen Hai Feng , Zhao Shi Jiang , Li Bin
Published: October 2011

This paper studied the influence of heat treatment on the pyrophyllite structure and acid-soluble properties of alumina. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by XRD, TG-DTA, FT-IR and quantitative analysis of Al2O3. The quantitative titration method studied the dissolve characteristics of the different heat treatment samples in different acid conditions, and then a numerical simulation was done. The results showed that at temperatures below 480 °C, the pyrophyllite did not change the basic structure. 480~700 °C dehydroxylation reaction occurred, and the structure water of pyrophyllite is removed, and then turned into partial pyrophyllite. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C, the dissolution amount of alumina was largest. These works could provide some theoretical basis for further application of pyrophyllite research.
RC Structure Durability Information Model Based on IFC
Authors: Ye Ying Hua , Liu Wen Peng , Diao Bo
Published: October 2011

An extension of the BIM technology that allows integrating durability factors into designing process, appraising durability and predicting residual life of building structures is proposed. Furthermore, by integrating national durability code, achievements of durability researches and the IFC standard which is developed by International Alliance for Interoperability (IAI) with the standard number of ISO10303 to facilitate AEC information sharing and exchanging, a BIM-Based Durability Appraising Software System for Reinforcement Concrete Structure is developed. The durability information model and IFC data interface are elaborated. Then the system is verified by a case study to be capable of improving lifecycle management of AEC projects, upgrading durability level and optimizing the lifecycle cost structure of building projects.
The Structure of Two-Dimensional Layered Cu (ΙΙ) Complex Material
Authors: Tai Xi Shi
Published: October 2011

A Cu (II) complex has been obtained by one-pot reaction of copper nitrate with 4-aminobenzene sulfonic acid, 2-acetylpyridine and sodium hydroxide. Unfortunately, the complex does not contain 2-acetylpyridine molecules, and 4-aminobenzene sulfonic acid coordinate to Cu (II) ion. The structure of Cu (II) complex was characterized by single-crystal X-ray diffraction. The results show that the complex crystallizes in monoclinic, space group P2(1)/n with a = 0.7437(3) nm, b = 1.7408(6) nm, c = 0.7644(3) nm, V = 0.8846(5) nm3, Z = 2, F (000) = 494, Rint = 0.0697, and the complex formed two dimensional layered structure through intramolecule and intermolecule hydrogen bonds and π-π stacking interaction.
Reaction Kinetics Analyses of Ethylenediamine Polyurea Curing Process
Authors: Zhu Hong
Published: October 2011

Novel sterically hindered chain extender, 2-acetyl-ethylenediamine (MEDA) was synthesized by acetylating of ethylenediamine(EDA) with glacial acetic acid in presence of phosphoric acid, in order to reduce high reactivity of synthesizing polyurea and study its kinetics equation. Its chemical structure was confirmed through FTIR and 1H-NMR analysis. Polyureas were synthesized by reaction of 4,4’-dipheSuperscript textnylmethane diisocyanate(MDI), amine terminated polyether(D-2000) with different chain extenders. The reaction kinetics of polyurea curing process was studied by FTIR. The results showed that extending reaction with MEDA was second order kinetic mechanism, its apparent activation energy was 36.81 kJ•mol-1.
Spatial Configurations of Molybdenum Atomic Chains
Authors: Shen Han Xin , Zhu Wen Zhang , Li Ai Yu
Published: October 2011

The geometric and electronic structures of Molybdenum chains are studied by the first-principles of density-functional method. The present calculations reveal that Molybdenum can form planner chains in zigzag, dimer, and ladder structures. The most stable geometry is the Dimer structure chain. The ladder structure is found to be more stable than the zigzag one. Furthermore, the relative structural stability, the electronic energy bands, the density of states are discussed based on the ab initio calculations.
Fabrication of Hydroxyapatite and Observation of Nanoparticles Entering into Cells
Authors: Yang Dong , Sun En Jie
Published: October 2011

Unambiguous and thorough knowledge of interactions between cells and nanoparticles was necessary for applications of nanoparticle in living system. In this report we presented systematic studies of fabrication of inorganic nanoparticles and the application of entering into cells. Size distribution, zeta potential and transmission electron microscope (TEM) were performed to characterize the nanoparticles structure and define the mechanism by which nanoparticles are capable of entering into cells. The study revealed nanoparticles can entered cells via penetrating through the lipophilic bilayer, which should be paid attention to for inspirational value insome application researches and will be harmful in other cases.
Preparation and Characterize of Konjac Glucomannan-Based Protein Molecularly Imprinted Polymer
Authors: Mi Zhi Yuan , Ma Zhuo , Li Xiao Li , Wang Pan , Zhang Ying Qing
Published: October 2011

Objective: To prepare a novel molecularly imprinted materials for protein recognition. Methods: Konjac glucomannan was used as fundamental materials, after swollen, added 3-Chloro-1,2- epoxypropane and glycerol cross-linked for 3 h at 40 °C. Then added bovine serum albumin (BSA) solution, agitated 1 h at room temperature. Natural dried. Results: After eluted, the imprinted efficiency of the imprinted membrane were (59.27±3.53) % (n=6) with blank membrane as control. The adsorption rate increased from 2 h to 20 h, and reached saturation at 22 to 24 h. The selectively recognition experiment indicated the BSA imprinted membrane have significant selectively recognition abilities for the template protein. Conclusions: konjac glucomannan-based imprinted membrane shows great possibilities to be a promising material for protein molecularly imprinted recognition.
Analysis to the Influences of Cutting Force to Machining Deformation of a Titanium Alloy Thin-Wall Tube
Authors: Yang Yu Hai , Guo Jian Ye , Yu Chao
Published: October 2011

This paper took a titanium alloy thin-wall splined tube as the object of research, and mainly analyzed the influences of cutting force to machining deformation of part in turning process. The paper first introduced the structure composition and characteristic of splined tube, then established the mathematical model of cutting force in turning process according to the orthogonal experiment method and the multiple regression algorithm, and finally the influences of cutting force to machining deformation of splined tube was carried on the simulation analysis with the aid of the finite element analysis software under the different cutting conditions. The conclusions of research in this paper will have important practical significance to reduce the machining deformation of thin-wall part and optimize the cutting parameters of difficult-to-machine material.
The Laminar Flow Simulation of Variable Diameter GFRP Pipe with Transition Region
Authors: Wang Ya Xuan , Ji Jing , Zhang Shu
Published: October 2011

To investigate the variation rule of fluidic speed in variable diameter GFRP pipe with transition region when the liquid flows through the pipe, the FLOTRAN CFD module of the ANSYS finite element software is adopted to take the laminar flow analysis on 4 diversion pipes with transition region in this paper. The finite element analysis process is introduced in detail, and the velocity vector distribution of the 4 diversion pipes is got. As can be seen from the graph, the velocity of the liquid begins to become quick before the liquid reaches transition region, the velocity of the central liquid is the fastest when the fluid passes the transition zone, the closer the distance is away the wall, the slower the liquid flows, and the distribution is conical basically. 37 degree is recommended in the transition region and it can provide the reference for the turbulent analysis of variable diameter GFRP pipe with transition region.
Simultaneous Localization and Mapping with Identification of Landmarks Based on Monocular Vision
Authors: YI Ying Min , Hui Yu
Published: October 2011

How to identify objects is a hot issue of robot simultaneous localization and mapping (SLAM) with monocular vision. In this paper, an algorithm of wheeled robot’s simultaneous localization and mapping with identification of landmarks based on monocular vision is proposed. In observation steps, identifying landmarks and locating position are performed by image processing and analyzing, which converts vision image projection of wheeled robots and geometrical relations of spatial objects into calculating robots’ relative landmarks distance and angle. The integral algorithm procedure follows the recursive order of prediction, observation, data association, update, mapping to have simultaneous localization and map building. Compared with Active Vision algorithm, Three dimensional vision and stereo vision algorithm, the proposed algorithm is able to identify environmental objects and conduct smooth movement as well.
Rural Electrification in Oyo State of Nigeria: Assessement of Existing 33kv Feeder Network Capacity
Authors: Melodi Adegoke Oladipo , Ajeigbe A.J.
Published: October 2011

The aim of this study was to assess the capacity of the existing primary feeder network (33 kV) and to determine ways of reinforcing it in view of prospective full scale electrification and power demand of the rural areas of Oyo State. This work was done by using data of maximum power demand allocations to fully electrified areas of the State to compute expected range of power demand per capita, and applying normal mode simulations and solutions using iterative approximation and direct matrix algebra methods. The results show that the load per capita range, and potential load demand for the State are 0.011 kW to 0.094 kW and about 534 MW (huge compared to current 103.7 MW supply from the utility) respectively. The capacities of existing networks and the total injection substations’ capacity (225 MVA) are inadequate for meeting the potential demand of Oyo State, including the rural areas. Upgrading the voltage of the existing network to 132 kV will improve its distribution capacity significantly and solve overloading and voltage problems. Also, installation of more 132 kV substations is needed to relieve the existing fully loaded ones. Otherwise, a full scale rural electrification development in Oyo State, intending to feed from the national grid, will be impossible.
Linear Conditioning of an NTC Thermistor Using Nonlinear Operational Amplifier Circuits
Authors: Agee John T. , Masupe Shedden , Modise Themba G.
Published: October 2011

Exponential nonlinearities in the thermistor limit the accuracy of the device for temperature measurement. This paper presents the design and implementation of a novel conditioning circuit for enhancing the accuracy of the sensor. Simulations of the conditioning circuit using MULTISIM were compared with the laboratory implementation. Results show that the proposed circuit could sufficiently linearise the thermistor characteristics and improve device sensitivity, throughout the range of sensor operation.
Performance Evaluation of GSM Service Providers around Igbinedion University Campuses
Authors: Abayomi-Alli A. , Ezomo P.I. , Etuk D.J. , Oghogho I. , Izilein F.
Published: October 2011

A performance evaluation of GSM service providers (Globacom, MTN and Zain) was conducted in Okada, Edo State; home of Igbinedion University. The main research objective was ascertaining the Quality of Service (QoS) provision level and fulfillment of minimum industry QoS standards of GSM operators. The GSM Key Performance Indicators (KPIs) and technical parameters measured included: percentages of call set-up success rate, call set-up failure rate, post dialing delay (intra/inter-network), call drop rate, call retention rate and call completion rate; credit balance inquiry success and failure; SMS delivery failures, incorrect feedback and multiple billing; recharge cards loading success, loading error and loading incorrect feedback. The measurements were carried out at different geographical positions of the town at varying time intervals. Observations were also made on some other performance issues like network availability, voice quality, call setup phase, post dialing delay-elongation, weather influence and signaling/ feedback. The study revealed several levels of KPI achievements by the different networks with Globacom performing best, coming tops in twenty-three (23) indicators out of the thirty-seven (37) considered followed by Zain and then MTN. It also revealed that the networks achieved some NCC QoS benchmarks and failed in some other notable ones.
Predicting Telephone Traffic Congestion Using Multi Layer Feedforward Neural Networks
Authors: Markus E.D. , Okereke O.U. , Agee John T.
Published: October 2011

Predicting congestion in a telephone network has become part of an efficient network planning operation. The excellent capability of neural network (NN) to learn complex nonlinear systems makes it suitable for identifying the relationship between traffic congestion and the variables responsible for its occurrence in a time-varying traffic situation. This paper presents an artificial NN model for predicting traffic congestion in a telephone network. The design strategy uses a multilayered feedforward NN with backpropagation algorithm to model the telephone traffic situation. Matlab was used as a platform for all simulations. Regression analysis between predicted traffic congestion volumes and corresponding actual volumes gave a correlation coefficient of 87% which clearly shows the utility and effectiveness of Neural Networks in traffic prediction and control.
Rural Mobile Telephony: A VSAT (Satellite) Based Approach
Authors: Idachaba Francis Enejo , Edeko F.O.
Published: October 2011

This work presents a VSAT based approach for extending mobile communication access to rural communities in developing countries using VSAT and satellite technology. The rural areas are clustered into village community cells with each cluster being served by a non regenerative bidirectional repeater system. The telecommunication technology of choice is the GSM standard. Traffic from the rural areas is collated together at the access point which serves as an interface between the village community cells and the satellite. The access points perform a frequency translation moving the signal from the GSM band to the satellite band at the transmitter and vice versa at the receiver. The system maximizes the advantage of satellite communication technology over other types in linking remote areas to urban centers that are geographically far apart. The satellite then links the village cell to the operator’s network via a dedicated BTS in the urban area. The system has the advantage of being modular, scalable and solar powered due to the low traffic from rural areas.
Adaptive MMSE Multiuser Detection in MIMO OFDM Wireless Communication System
Authors: Eneh T. , Rapajic P. , Anang K. , Lawal Bello
Published: October 2011

The combination of MIMO signal processing with OFDM is a solution to achieving high data rates for next generation wireless communication systems operating in frequency selective fading environments. To realize the extension of the MIMO with OFDM, a number of changes are required in the baseband signal processing. The developed adaptive Multiuser Detection in MIMO OFDM(AMUD) scheme performs better compared to non adaptive MIMO OFDM, at low Signal to noise ratio (SNR), it shows good performance in computational complexity, bit error rate (BER) and capacity. Simulation results show that the developed algorithm sum rate capacity is very close to MIMO theoretical upper bound (21.5 bits/s/Hz at signal to noise ratio of 20dB) which strongly indicate it’s applicability to the uplink channel where power transmission at the mobile station is a constraint. The BER performance of the developed scheme shows that, as the number of antenna increases, the 8 x 8 AMUD provides a 2dB gain compared to known non adaptive MIMO OFDMO at low SNR.
Evaluation of Wood Properties of C. albidum Tree Grown in Akinyele Local Government Area of Ibadan, Nigeria in Relation to its Utilization
Authors: Adewole N.A. , Ajibi A.B.
Published: October 2011

Fruit trees are hardly ever sought for their wood until recently. Fruit trees like C. albidum is now being used for structural and non structural purposes in city suburbs. This study investigated wood properties and few tree characteristics of C. albidum grown in Akinyele Local Government Area (ALGA), Ibadan, Oyo State, Nigeria. The aim was to mitigate the dearth of information on these features in relation to its utilization. Samples were collected from five emerging settlements in the study area while structured questionnaire and on-the-spot assessment were the instruments employed for data collection during survey stage. Physical appearance, moisture content (MC), green and oven-dry density, specific gravity of oven-dry samples, natural durability against termite, modulus of elasticity (MOE) and modulus of rupture (MOR) were determined via experimentation. Samples used for static bending strength were prepared in accordance with ASTM D 143 standard of 1991. The obtainable mean bole length, basal, middle and top girths were 4958mm, 1823mm, 1473mm and 1427mm respectively and the tree is moderately buttressed. The wood is brownish-white, crossed grain, coarse textured and fairly resistant to termite attack. Averagely on wet basis, MC and density are 52.46 %, 949 kg/m3 respectively and dry density is 739 kg/m3. Also MOR and MOE are respectively 1964N/mm2 and 1163.60N/mm2. The wood density compares with that of few commercially known tree species in N7-strength group thus preferred for non-structural than structural use especially when high bending stress is required.
Rheological and Some Fuel Properties of Fatty Acid Methyl Esters of the Oils of Palm, Palm Kernel and Groundnut
Authors: Eze V.C. , Ejikeme Paul M. , Onukwuli D. Okechukwu
Published: October 2011

Production and characterization of fatty acids methyl esters (FAME) from palm oil (PO), palm kernel oil (PKO) and groundnut oil (GNO) were carried out in this study. Optimal amount of NaOH catalyst required for the transesterification of the degummed and refined oils were determined. Some rheological and fuel quality parameters of the FAME obtained from batch transesterification of each oil, petrodiesel and their blends, were determined. The optimal catalyst weights obtained, based on oil, were 0.40, 0.48 and 0.56 (%wt/v) for GNO, PKO and PO, respectively. The FAME produced had viscosities of 4.45, 3.44, and 4.11mm2/s as compared to the 38.84, 37.51 and 36.92mm2/s obtained for the parent oils PO, PKO, and GNO, respectively. The measured viscosity of petrodiesel was 2.85mm2/s. Thermodynamic free energies of activation for flow (∆Gvis) for the FAME samples were 18.1, 13.4 and 14.7KJ/mol for PO, PKO, GNO, respectively, and 10.1KJ/mol for petrodiesel.
Use of "Shikoko” Clay for Synthetic Sand Moulding
Authors: Eze E.O. , Ileli L.E.
Published: October 2011

“Shikoko” clay and dredged river sand from Warri, Nigeria were investigated for their use in synthetic sand moulding. Shikoko is a local name for organic clay that dries appreciably to a brownish gray, leather-like consistency. The clay was initially tested for organic matter content, natural water content, particle size distribution, consistency limits and linear shrinkage. The base sand dredged river sand from the same town - was tested for specific gravity, and grain size characteristics. Tests showed that the best mix with the clay was at the binder contents of 13, 17, 33 and 50% of the dry weight of the sand. The synthetic sand mixture was tested for the dry and green compressive strengths, and green permeability. At clay contents of 13 and 17 %, the green and dry compressive strengths of the synthetic mixtures at 5, 10, 15 and 20% moisture contents compared well and were at times higher than the corresponding values for synthetic moulds used in founding. Test results indicated that the synthetic mixture can be used for light casting and in non-ferrous production.
Adsorption Isotherms for Naphthalene on Clay and Silt Soil Fractions: A Comparison of Linear and Nonlinear Methods
Authors: Owabor C.N. , Oboh I.O. , Omiojieahior F.A.
Published: October 2011

Polycyclic aromatic hydrocarbons occur naturally in petroleum oil and coal and the burning of fuel and the activities of paper mills also release these compounds to the environment. Batch experimental adsorption study for both soil fractions was conducted in a soil slurry system at ambient temperature, using <0.02mm particle sizes. Comparison was made of the linear least-squares method and a trial-and-error nonlinear method of some widely used isotherm models for the adsorption of naphthalene on clay and silt fractions. The experimental results were fitted to the Langmuir, Freundlich, Radke-Prausnitz, Sips, Temkin and Redlich-Peterson isotherms to obtain their characteristic parameters of each model. The coefficient of determination obtained from the different models using the linear method showed that Freundlich isotherm had the highest values for both clay and silt soil fractions with values of 0.843 and 0.897 respectively. The equilibrium data did not fit the Langmuir isotherm with values of 0.287 and 0.021 for clay and silt soil respectively. Using the nonlinear method the equilibrium data gave good fit for Radke-Prausnitz, Sips, Temkin and Redlich-Peterson isotherms. Sips isotherm gave the best fit for silt soil with the r2 value of 0.9779 and this was followed by Temkin isotherm for clay soil with the value of 0.9673.
Challenges of Deepwater Developments
Authors: Oyeneyin Babs Mufutau
Published: October 2011

This keynote paper attempts to catalogue the key business drivers for deepwater developments especially for the Mediterranean, Gulf of Guinea, Gulf of Mexico and other deepwater environments and the challenges arising thereof. The paper goes further to provide some in-depth analysis of the key technical issues such as subsea production systems integrity, multiphase flow assurance management, lessons learned from the shallow water as well as the deepwater areas like the North Sea before addressing some of the technology developments and competency required to take the new regions forward. . The paper ends with a presentation of what the new National Subsea Research Institute [NSRI] in the United Kingdom is doing and can do to support future deepwater developments.
Rheological Characterisation of Heavy Oil and Impact on its Production Enhancement
Authors: Bali Amol , Oyeneyin Babs Mufutau , Adom Ebenezer
Published: October 2011

Criticality of rheology for heavy oil recovery is the main purpose of this paper supported by different results. The Bingham Plastic, Power Law and Herschel Bulkley rheological models have been adopted for the purpose of this paper. Rheological characterisation was carried out for different temperatures. Rheological behaviour of non-Newtonian heavy oil for different shear rates is analysed in this paper. Effective shear and bulk viscosities for different flow rates are compared for all rheological models. Using the horizontal well productivity model, the drawdown values for all rheological models are determined. Similarly for the sand management purpose the critical rates of Newtonian and these three non-Newtonian fluids are plotted to determine the critical drawdown values for each type of fluid. Impact of drainage profile on the effective viscosities is also compared for different drainage profiles. Shear rate models are proposed in this paper for Bingham Plastic, Power Law and Herschel Bulkley rheological models. The new Micro-PVT equipment is also introduced for determining the PVT properties and rheological behaviour of heavy oil. Nomenclature
A Novel Approach to Subsea Multiphase Solid Transport
Authors: Bello Kelani , Oyeneyin Babs Mufutau , Oluyemi Gbenga Folorunso
Published: October 2011

Transportation of multiphase reservoir fluid through subsea tiebacks has gained considerable attention in recent years especially in the deep offshore and ultra deep offshore environments where there is increasing pressure on the operators to reduce development costs without compromising oil production. However, the main challenge associated with this means of transporting unprocessed reservoir fluids is the need to guarantee flow assurance and optimise production. Solids entrained in the fluid may drop off and settle at the bottom of horizontal pipe thereby reducing the space available to flow and causing erosion and corrosion of the pipeline. The problem has been largely attributed to insufficient flow velocity among other parameters required to keep the solids in suspension and prevent them from depositing in the pipe. The continuous changing flow patterns have introduced additional complexities dependent on gas and liquid flow rates. Acquisition of experimental data for model development and validation in multiphase flow has been largely focused on single and two phase flow. This has impeded our understanding of the behaviour and associated problems of three phase or four phase (oil, water, gas and solid) in pipes. The result is inappropriate solid transport models for three phase and four phase. In order to bridge this gap, the Well Engineering Research group at Robert Gordon University has initiated a project on integrated multiphase flow management system underpinned by comprehensive experimental investigation of multiphase solids transport. The project is aimed at developing precise/accurate sand transport models and an appropriate design and process optimisation simulator for subsea tiebacks. In this paper, the physics of the multiphase transport models being developed is presented. The models will allow for the prediction of key design and operational parameters such as flow patterns, phase velocity, pressure gradient, critical transport velocity, drag & lift forces, flow rate requirements and tiebacks sizing for transient multiphase flow. A new multiphase flow loop is being developed which will be used to generate experimental database for building and validating the theoretical models for use in a proposed integrated simulator for deepwater applications.
Heavy Oil Recovery: A Cold Process Using CO2-EOR Technique
Authors: Tchambak Eric , Oyeneyin Babs Mufutau , Oluyemi Gbenga Folorunso
Published: October 2011

Owing to substantial improvement in enhanced oil recovery (EOR) technologies and significant decline in discovery of light and medium crude oil fields, the heavy oil development is progressively receiving considerable attention to fill the supply gap. Cold heavy oil production (CHOP) using captured carbon dioxide (CO2)-EOR technique was investigated using the state-of-the-art Integrated Product Modelling packages of Petroleum Experts as part of the Well Engineering Research Group unconventional oil reservoir management studies being undertaken at Robert Gordon University. Beyond ascertaining the feasibility of the CHOP using CO2-EOR, the objectives of the investigation were to establish the process requirements at the onshore facilities based on series of parametric studies and to enhance the understanding of the subsea integrated injection and production systems during the injection process. The injection system consisted of an injection well connected to a 240 km subsea pipeline transporting CO2 from an onshore compression station. The production system included a topside separator connected to the production well via a 2km riser. A broad range of reservoir production history was used and the simulation results indicate that heavy oil displacement was easily achievable under miscible conditions (i.e. high reservoir pressure), but the production trend was strongly influenced by the reservoir characteristics (i.e. GOR, WC, Pressure).
Modeling Gel Break-Time in Gravel Pack Fluids as a Function of Breaker and Activator Concentrations with Temperature
Authors: Akonye U.U. , Joel Ogbonna F.
Published: October 2011

Break time results carried out for 60Ibs/Mgal linear gel at different breaker and activator concentrations with temperatures for gravel pack jobs done in the past was used in this study. Temperature range investigated was from 180oF to 215oF. A mathematical model was developed for break time prediction as a function of temperature and breaker/activator concentrations. The model was regressed with experimental data using the regression tool in Microsoft Excel. Results of the model prediction were validated with experimental data. The model break time predicted showed good agreement with experimental values with less than 2% deviation. The model equation developed will help predict the break time at the various breaker and activator concentrations at different temperatures. This will help in saving time associated with the rigour in actual laboratory experimental design and testing. This will no doubt improve operational efficiency and service quality delivery.
Environmental Compliance Monitoring of Selected Physico-Chemical Parameters of Effluent Discharge from Gulf of Guinea Near-Shore / Offshore Facilities
Authors: Joel Ogbonna F. , Akinde S.B.
Published: October 2011

Tests were conducted to analyze selected physico-chemical and microbiological parameters from samples of effluent collected from Gulf of Guinea onshore house-boat facilities and offshore oil production platforms at the discharge point to the recipient environment. Among the parameters determined included: Total chlorine, Biochemical Oxygen demand (BOD), Total Suspended Solids (TSS), Dissolved Oxygen (DO) and Faecal coliform. The discharge loads were evaluated and monitored for eight weeks. Test results indicated that the mean value for total chlorine ranged from 0.12 to 0.60 mg/l for onshore and from 0.26 to 1.4 mg/l for offshore. The BOD5 mean values for the onshore facilities ranged from 15.3 to 52.5 mg/l, for the offshore facilities, it ranged from 27.60 to 117.7 mg/l. The onshore result of the TSS mean values ranged from 53.9 to 62.4 mg/l, the offshore facilities ranged from 77.1 to 242.6 mg/l. The DO mean value results from the onshore facilities ranged from 3.6 to 6.2 mg/l and the result from the offshore facilities ranged from 4.8 to 5.60 mg/l. The faecal coliform for the onshore facilities had a mean value which ranged from 4.0 to 30.1 MPN/100ml, while the offshore facilities had mean value range of 7.4 to 42.0 MPN/100ml. Most of these results are higher than limits specified by the Department of Petroleum Resources (DPR) and an indication that the recipient environment is polluted and poses a great concern. There is therefore utmost need for further treatment before discharge for those parameters that indicated higher ranges than specified for effluent discharge.
Determination of the Ovality of Crude Oil Storage Tanks Using Least Squares
Authors: Ehigiator R. Irughe , Ehiorobo J.O. , Beshr Ashraf A. , Ehigiator M.O.
Published: October 2011

In the processing of field measurements, the observations are adjusted using the least squares principle which gives unbiased estimate of the parameter sought together with their accuracies. In this paper, the use of the Least Squares model in the determination of the tank radius, centre point coordinates and ovality are discussed. The circular cross section of the crude oil storage tanks was divided into sixteen monitoring stations at equal intervals around the tank and at an elevation of 2m from the tank base. Total station instrument was then used to carry out angular and linear measurements by method of multiple intersection to reflectors held on the studs. The field measurements were post processed and adjustment of observation carried out by Least Squares adjustment method. The adjusted coordinates together with the computed radius were then used to determine tanks ovality. All data processing and adjustment were carried out with the aid of MATLAB Software for the 2003, 2004 and 2008 measurement epochs.The results of the study revealed an expansion of the tank shell between 2004 and 2008 measurement epoch. The radius of the tank was computed to be 38.187m in 2003 and 2004 and 38.205m in 2008 respectively.