Flexural response of reinforced concrete members strengthened with near-surfaced-mounted CFRP strips
October 2013
Tests and analyses were performed in this study to assess the flexural strengthening capacity of reinforced concrete (RC) members strengthened by the near surface mounted (NSM) technique, which is drawing attention as an alternative to the carbon fiber reinforced polymer (CFRP) bonding strengthening technique. Four-point bending tests were performed on 14 RC specimens. The test variables such as section geometry...
Adsorption of Cr(III) and speciation of chromium in aqueous solution using Ambrosia beetle-generated acacia polycantha frass
October 2013
Acacia polycantha frass (APF) generated by boring activity of Ambrosia beetles was investigated using a batch technique for its potential to adsorb Cr(III) ions from aqueous solution. Studies were carried out to determine the effect of pH, adsorbent dose, and KBr concentration on the sorption behavior Cr(III) on the adsorbent. The adsorption process was found to be highly dependent on solution pH with maximum removal...
Variation of source distribution of total oxidants: Contributions of oxides of nitrogen, sulphur (IV) oxide emissions and background ozone from Lagos-Nigeria
October 2013
Air dispersion modeling system (ADMS)-urban was used as air dispersion tool to model the atmospheric pollutants composition over Lagos air shed. The model runs with single point source showing the variation of concentrations of air pollutants (NO2, NOx, O3, and SO2) with ambient air dispersion over the city of Lagos, Nigeria. This city is located in the coastal area, and is highly congested with a high intensity of...
Heavy metals concentration levels in selected arable agricultural soils in South Western Nigeria
October 2013
The application of micronutrient supplements such as fertilizer, animal manure and sewage sludge in bid to enhance soil productivity and crop yield, poses the risk of heavy metals elevation and nutrients depletion in arable lands. Arable soils were collected from farmlands in use for the cultivation of food produce in selected farming communities in South Western Nigeria. The soils were...
Evaluation of performance of z-component of Nigerian seismographic stations from spectral analysis
October 2013
Preliminary noise analysis has been carried out on the Z-components of the Nigerian National Network of Seismographic Stations (NNNSS) using data collected from the five operational stations (Toro, Kaduna, Nsukka, Awka and Ife) in 2012. The results of the analysis from noise spectra using SEISAN software clearly showed that the noise levels at the respective stations are high and the average noise levels are above the...
Co-digestion of cattle manure with organic kitchen waste to increase biogas production using rumen fluid as inoculums
October 2013
Anaerobic co-digestion strategies are needed to enhance biogas production when treating certain residues such as cattle/pig manure. Co-digestion of food waste with animal manure or other feedstocks with low carbon content can improve process stability and methane production. In this study, anaerobic digestion and co-digestion of cattle manure with organic kitchen waste using rumen fluid as inoculums have been...
On consistency and security issues in collaborative virtual environment systems
October 2013
This paper survey security issues in collaborative virtual environments (CVEs) systems. In CVE, multiple users work on different computers which are interconnected through different networks to interact in a shared virtual world. Due to the nature of the geographically disperse users and their connection via different networks, there are numerous security threats that denied fulfillments of most important CVE...
Studies on the potentials of Balanites aegyptiaca seed oil as raw material for the production of liquid cleansing agents
October 2013
The seed oil of Balanites aegyptiaca was extracted and its chemical and physical properties were evaluated. The chemical parameters investigated include: saponification value (SV), iodine value (IV), peroxide value (PV) and free fatty acid (%FFA). These were found to be 168.6 mgKOH/g, 78.7 gI2/100 g, 6.0 mEq/kg and 0.18 mgKOH/g, respectively. The physical parameters evaluated include: percentage yield (49.9%),...
Physicochemical investigation of the drinking water sources from Mardan, Khyber Pakhtunkhwa, Pakistan
October 2013
A total of 39 drinking water sources were analyzed for important physicochemical parameters to evaluate their suitability for human consumption. Samples were collected from the ground water supplies (tube wells, open wells and hand pumps) of highly populated 13 union councils from the urban area of district Mardan. Physical parameters studied include temperature, color, taste, odor, total dissolved solids (TDS),...
Multi-core large-scale image-based modeling
October 2013
Large-scale image-based modeling is a challenging and important research topic, which has wide applications in various areas. Existed serial methods consume a significant amount of time for large problems. With the emergence of multi-core computers, it is possible to speed up the method using central processing unit (CPU) parallelism. In this paper, we present the design and implementation of multi-core large-scale...
Dry season predictive technique for estimating the hydrocarbon degradation in a continuous discharge of wastewater in pond system
October 2013
A new correlation has been developed in this paper for predicting hydrocarbon degradation in a continuous discharge of wastewater in a pond system for dry season. The correlation was developed using force balance model on a fluid element in a pond (hydrodynamic model). Mathematical technique known as separation of variables was applied to the general solution obtained from the hydrodynamic model. The degradation rate of...
Seismic refraction and resistivity imaging for assessment of groundwater seepage under a Dam site, Southwest of Saudi Arabia
October 2013
Seismic refraction and resistivity imaging methods were used to investigate a Dam site in Southwest Saudi Arabia to delineate the source and pathway of groundwater seepage in the site. The selected methods have the possibility to give an image of the subsurface and map lateral and vertical variations in the subsurface geology of the site. For this purpose, 48-channels seismograph with geophone spacing of 5 m,...
Factors influencing the performance and efficiency of solar water pumping systems: A review
October 2013
The world is having an energy crisis and currently there is a strong drive towards renewable energy. A renewable energy option is solar energy, where by means of photovoltaic (PV) modules electrical energy can be produced. A residential as well as industrial application for these PV modules is solar water pumping systems. Disadvantages of solar water pumping systems are low performance and low energy efficiency. This...
A supplement to the Michelson-Morley experiment
October 2013
Based on the great Michelson-Morley experiment and predecessors’ analyses, this famous experiment was reviewed under the principle that velocity of light is independent of the motion of the light source emitting or reflecting it, mainly on time difference or optical path difference (OPD). We will discover in this work that predecessors’ analysis on the famous experiment may be improper, and that there is no...
Solution and dynamics of a fourth rational difference equation
October 2013
In this paper, we get the form of the solutions of the following nonlinear recursive sequences of order four where the initial conditionsare arbitrary real numbers. Also, we study some qualitative behaviors of the solutions as periodicity character of the solutions of these different equations and we obtain the equlibrium points of considered difference equations in order to investigate the local...
Vibration reduction and stability study of a dynamical system under multi-excitation forces via active absorber
October 2013
An active vibration absorber for suppressing the vibration of the nonlinear system when subjected to external and parametric excitations forces will be studied. The aim of this paper is to study the effect of the nonlinear controller on the vibrating system. The approximate solutions up to the second order are derived using the method of multiple scale perturbation technique near the primary, principal parametric...
Thermo-electrical characterization of Lead-Cadmium (Pb-Cd) alloys
October 2013
Thermal conductivities of solid phases for pure Lead (Pb) and Pb-x wt.% Cadmium (Cd) (x = 3.3, 5, 12, 17.4, 50, 95, 99.75) binary alloys were measured with a radial heat flow apparatus. The variations of electrical conductivity (σ) on temperature and composition for the Pb-Cd alloys were measured with DC four-point probe technique. It has been observed that the electrical conductivity of Cd-based Pb-Cd alloys...
Electrical, structural and thermal properties of graphite/silicone blends
October 2013
We report the results of electrical, structural and thermal investigations on graphite/Silicone blends (G/Silicone), obtained by dispersion of graphite powder in an insulating matrix of rubber silicone. The X-ray diffraction analysis showed crystalline structure for our all studied (G/Silicone) blends. Conductivity measurements were reported in the temperature range of 298 to 423 K. The blends showed percolation...
Determination of the vertical variations in temperature and longwave radiation within the gray Earth’s troposphere using radiative equilibrium profile model
September 2013
This study estimated the vertical variation in mean temperatures within the tropospheric layer using the radiative equilibrium profile model and longwave radiation with Stefan-Boltzmann equation at a tropical meteorological station located besides Physics Building (7.55°N:4.56°E), Obafemi Awolowo University, Ile-Ife, Nigeria. In the model, the height of the troposphere was assumed to be...
Comparison of selected physical properties of deep peat within different ages of oil palm plantation
September 2013
The environment of young and mature oil palm plantation were found to be different due to the size of the oil palms and the depth of water tables applied. The environments in both sites have probably influenced the changes of peat soil physical properties towards the peat land degradation. A study was carried out to compare selected physical properties of deep peat between two different ages of oil palm plantation...
Coupled-operations model and a conditional differential evolution algorithm for improving reservoir management
September 2013
This paper proposes a flexible methodology for finding the optimal control of reservoir operations, which is adopted for simulating a storage system including a large reservoir simulation model and a numerical search method for searching decision variables. The optimization model used was a conditional differential evolution algorithm (CDE). The model was connected to reservoir simulation model for searching the...
A multilevel fast multiple method for computing the propagation of multiply scattered 2.5-D teleseismic surface waves underneath a linear or quasi-linear seismic station array
September 2013
We introduce an algorithm for the forward modeling of multiple scattering of teleseismic surface waves where the underground structure beneath the linear (or quasi-linear) seismic station array is assumed two-dimensional and the teleseismic surface waves may be approached from an arbitrary direction. The current algorithm is two-and-half-dimensional since even though the structure is two-dimensional, the displacements...
A new approach on production of slope map using autonomous Unmanned aerial vehicle
September 2013
Many studies have been done previously to generate a slope map at the area of interest. However, most of these methods can be time consuming and they require huge cost. Currently, aerial mapping using Unmanned aerial vehicle (UAV) is very popular in the mapping field. UAV can promise a high accuracy data with low cost and less time needed to produce a slope map at certain area. Therefore, a scientific approach needs to...
Earthquake precursory studies at Amritsar Punjab, India using radon measurement techniques
September 2013
The continuous soil gas radon and daily monitoring of radon concentration in water is carried out at Amritsar (Punjab, India), a well known seismic zone to study the correlation of radon anomalies in relation to seismic activities in the study area. In this study, radon monitoring in soil was carried out by using barasol probe (BMC2) manufactured by Algade France whereas the radon content in water was recorded using...
Motion groups and circular helices in Lorentz 3-space
September 2013
In this paper, we find the curves which are orbits of points under the homothetic and helicoidal motion groups in Lorentz 3-space. Also, we show that if these curves are Frenet curves then their curvature and torsion are constant. So we can say that these curves are circular helix in Lorentz 3-space. Key words: Helix, homothetic motion groups, helicoidal motion groups, Frenet curves.
A note on dynamical systems satisfying the Wünschmann-type condition
September 2013
Dynamical systems of second order ordinary differential equations (SODEs) satisfying the Wünschmann-type condition are presented, with a special emphasis on SODEs provided by Euler-Lagrange equations, particularly, geodesics on surfaces. Some remarkable facts are to be pointed: three of our examples are of quasi Euler-Lagrange nature; also, except one example that leads to classical Euclidean 2D metric, all yields...
A nonlocal integral boundary value problem of nonlinear integro-differential equations of fractional order
September 2013
This study discussed the existence of solutions for a nonlinear fractional integro-differential equation of order with four-point nonlocal integral boundary conditions. The given problem is transformed to an equivalent fixed point problem in terms of an operator equation. Then, by means of Banach contraction principle and a fixed point theorem due to Krasnoselskii, the existence results are obtained. The last...
Role of Rose Bengal-Mannitol system for generation of electrical energy in photogalvanic cell
September 2013
Photogalvanic effect was studied in photogalvanic cells containing Rose Bengal as dyes and Mannitol as reductants. The photogalvanic cells were determined by the photo potential, photocurrent, conversion efficiency, power of cell and performance of cell. The effects of various parameters like pH, light intensity, diffusion length, reductant concentration and dye concentration on the electrical output of the cell is...
Numerical and experimental evaluation of bearing capacity factor Nγ of strip footing on sand slopes
September 2013
Results of laboratory model tests and numerical studies on the behavior of a strip footing adjacent to a sand slope are investigated and presented in this paper. The investigated parameters include the effects of depth of the first reinforcement layer, vertical spacing, number of reinforcement layers, and distance between the edges of footings on bearing capacity. Results were analyzed to determine the effects of each...
Magneto hydrodynamic (MHD) squeezing flow of a Casson fluid between parallel disks
September 2013
Squeezing flow of a Casson fluid is considered between two parallel disks. Upper disk is taken to be impermeable but capable of moving towards or away from the lower fixed and porous disk. Governing equations are derived with the help of conservation laws combined with suitable similarity transforms. Homotopy analysis method (HAM) is then been employed to determine the solution to resulting ordinary differential...
Excessive correlated shifts in pH within distal solutions sharing phase-uncoupled angular accelerating magnetic fields: Macro-entanglement and information transfer
September 2013
Entanglement or “excess correlation” between physical chemical reactions separated by significant distances has both theoretical and practical implications. In 24 experiments, the inverse shifts in pH were noted in two quantities of spring water separated by 10 m that shared rotating magnetic fields (0.5 µT) with changing angular velocities when one solution was injected with proton donors (weak acetic...
Synthesis and use of hydrotalcites as heat stabilisers in thermally processed powdered polyvinylchloride (PVC)
September 2013
Lead-based stabilisers, such as lead sulphate and lead stearate, currently used in the processing of polyvinylchloride (PVC) products are being substituted with more environmentally safe, economically viable and higher quality materials. This study aimed to use hydrotalcites (HTs), which are environmentally non-hazardous and simple to synthesise, to effectively quench the HCl gas evolved during the degradation of PVC....
Geoelectrical studies for the delineation of potential groundwater zones at Oduma in Enugu State, Southeastern Nigeria
September 2013
This work evaluates the use of geoelectrical method in the delineation of potential groundwater zones at Oduma in Enugu state, Southeastern Nigeria. Oduma lies within latitudes 6°02Ë¡ N to 6°07Ë¡ N and longitudes 7°35Ë¡ E to 7°41Ë¡ E with an area extent of about 102.6 km2. The area is underlain by Awgu Shale group with its lateral arenaceous facie; Owelli Sandstone outcropping south...
Performance analysis of a Ĉuk regulator applying variable switching frequency
September 2013
This paper examines the performance of Ĉuk regulator to convert three phase alternating current (ac) to direct current (dc). Firstly, three phase ac is rectified with bridge diode. The rectified dc voltage is applied to input of a Ĉuk regulator. Three phase harmonics filter is introduced at the input of the diode rectifier to improve the shape of the input current. The main technique applied here to improve the...
Wavelet based dynamic Mel Frequency Cepstral Coefficients (MFCC) and block truncation techniques for efficient speaker identification under narrowband noise conditions
September 2013
Speaker identification strategies are well convincing in their performance when clean speeches are scrutinized. But the performance degrades when speech samples are corrupted by narrowband noise. Block truncation of the cepstral coefficients ensures that not all the features are affected by narrowband noise but it cannot reduce the extent of degradation. This work is focused towards improving the performance of speaker...
Plasma properties of nano-second laser ablated iron target in air
September 2013
In the present work, we studied the optical emission spectra of iron (Fe) plasma produced by the fundamental (1064 nm) and second (532 nm) wavelengths of an Nd: YAG laser. The plasma emission has been recorded spatially using five spectrometers covering the spectral region from 200 to 720 nm. The laser beam was focused on target material by placing it in air at atmospheric pressure. The experimentally observed line...
Influence of fuel in the microwave assisted combustion synthesis of nano α-alumina powder
September 2013
Microwave assisted combustion synthesis is used for fast and controlled processing of advanced ceramics. Single phase and sinter active nano crystalline alpha alumina powders were successfully synthesized by different fuel-to-oxidant molar ratios using aluminium nitrate as an oxidiser, glycine as a reducing agents and millipore water as a solvent by microwave assisted combustion synthesis. Thermodynamic modelling of the...
Second-order kinetic model for the adsorption of divalent metal ions on Sida acuta leaves
September 2013
The removal of metal ions from effluents is of importance to many countries of the world both environmentally and for water re-use. A comparison was made of the linear least-squares method of the widely used pseudo-second order kinetic model for the sorption of some divalent metal ions onto Sida acuta leaves. Four pseudo-second order kinetic linear equations were used for this study. The results obtained from...
Effect of dielectric constant on energy losses in lead sulphide thin films grown by solution method at room temperature
September 2013
Thin films of lead sulphide (PbS) were deposited using chemical bath deposition (CBD) at different lead ion concentrations. A mixture of sodium hydroxide, varied concentrations of lead nitrate, triethanolamine (TEA), ammonia solution, thiourea, di-ionized and distilled water were used. A dip time of 120 min and pH of 9 at room temperature were maintained. It was found out that dielectric constants of the films...
Singulo oscillatory – stiff rational integrators
September 2013
In this paper, we derive a general singulo oscillatory – stiff rational integrator of order (S+3) for s = 0, 1, 2, 3, 4,… for the solution of initial value problems in ordinary differential systems that are singular, oscillatory or stiff. We compared our integrators with certain maximum order second derivative hybrid multi-step methods, certain Tau and Euler methods, the adaptive implicit and classical...
Structural health monitoring and damage assessment Part I: A critical review of approaches and methods
September 2013
Aging and deterioration of existing structures and the need for rapid assessment and evaluation of these structures for hazard mitigation have significantly expanded the research efforts in the field of structural health monitoring (SHM). SHM involves monitoring of a structure using periodically sampled measurements, extraction of damage sensitive features from these measurements, and assessment of the current health...
Multiband fractal based reconfigurable antenna with introduction of RF MEMS switches for next generation devices
August 2013
Next generation network’s main requirements are compact size and also support to heterogeneous network. Fractal antennas have useful applications in cellular telephone and microwave communications. Video conferencing, streaming video are main applications that are included in next generation networks and requirements for these applications are high data rates require to have high bandwidth. But as size of antenna...
Effect of stabilizers on stiffness modulus of soil layers: A review
August 2013
Subgrade layer has a significant contribution in the pavement structure, and the quality of this layer has a great impact on the subsequent pavement design. Pavement design guide as specified in the AASHTO (2002), incorporates engineering properties of unbound and stabilized subgrade soils, since in many cases fatigue or rutting failure in pavements are due to insufficient stiffness modulus in soil layers. Subgrade...
Almost quaternionic integral submanifolds and totally umbilic integral submanifolds
August 2013
In this work, we consider a Riemannian manifold which admits an integrable distribution with an almost quaternionic structure V. We show that the torsion tensor of an almost quaternionic structure is independent of the choice of bases. We prove that the integral submanifolds are totally umbilic under the condition of the conjugate shape operator is skew-adjoint. We give another condition...
Synthesis and characterization of polyindole with liquid crystalline azobenzene as side chains
August 2013
In this study, a series of azobenzene-functionalized liquid crystalline (LC) polyindole derivatives: poly{2-[N-ethyl-N-[4-[4'-(nitrophenyl)azo]phenyl]amino]ethyl-3-indolyl acetate}, poly(In3AA-RedI), poly{2-[N-ethyl-N-[4-[4'-(nitrophenyl)azo]phenyl]amino]ethyl-3-indolyl acetate-co-indole}, poly(In3AA-RedI-co-In), poly{2-[N-ethyl-N-[4-[4'-(nitrophenyl)azo]phenyl] amino]ethyl-3-indolyl...
Synthesis and characterization of nano-hydroxyapatite (n-HAP) using the wet chemical technique
August 2013
Hydroxyapatite nanoparticles were synthesized, using a wet chemical technique with diammonium hydrogen phosphate and calcium nitrate tetrahydrate precursors, respectively. The pH of the system was maintained at 10.8 throughout the stirring process, by using 0.1 M sodium hydroxide. The mixture was allowed to remain stirred overnight and a white precipitate was formed. The precipitate was vacuum dried and cleaned with...
Optical properties of as-deposited TiO2 thin films prepared by DC sputtering technique
August 2013
Amorphous titanium dioxide TiO2 thin films have been deposited using the dc sputtering technique. The structure of the films was analyzed by X-ray diffraction and the results showed non-crystalline behavior. The optical properties of these thin films have been investigated by means of optical reflectance and transmittance spectra. The optical energy gap Eg, the Urbach tails Eu, the single oscillator energy Eo, the...
Synthesis, structural and optical characterizations of cadmium oxide (CdO) thin films by chemical bath deposition (CBD) technique
August 2013
Thin films of cadmium oxide (CdO) were synthesized and characterized using chemical bath deposition (CBD) technique. The XRD studies revealed amorphous CdO thin films which upon annealing at 623K transformed to polycrystalline structure. The optical studies showed that the CdO films have high average transmittance over 60% in the visible region and direct optical bandgaps of 2.02 ± 0.05 eV, 2.03 ± 0.05eV...
Flow behaviour of polyvinyl alcohol (PVOH) modified blends of polyvinyl acetate (PVAc)/natural rubber (NR) latexes
August 2013
During compounding processes, polymer latexes are mixed with various colloidal systems (in particular, PVOH) or surface-active agents to modify the flow behaviour in order to suit the manufacturing process. In this study, the flow behaviour of aqueous dispersed PVAc, NR and different mixed dispersions were investigated both in the absence and presence of PVOH as flow modifier, using an Ostwald glass capillary...
Structural and DC Ionic conductivity studies of carboxy methylcellulose doped with ammonium nitrate as solid polymer electrolytes
August 2013
Solid polymer electrolytes have been prepared by solution casting technique. Carboxy methylcellulose (CMC)-ammonium nitrate (AN) films were studied with varied AN salt concentration from 5-50 wt.% at ambient temperature. X-ray diffraction (XRD) pattern shows the amorphous nature of polymer electrolyte samples. IR-spectra confirm the polymer-salt complexes in the range of 1633 - 829 cm-1. Impedance analysis reveals that...
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