Laser-induced emission from dye-doped nanoparticle aggregates of poly (DL-lactide-co-glycolide)
January 2008
Stable nanoparticles of poly (DL-lactide-co-glycolide) (PLGA) have been prepared, which is photosensitized with near-infrared chromophores doped into the particle. Laser-induced white-light emission is observed from aggregates of the dye-doped nanoparticles, which shows spatial interference of nonlinear optical processes as the underlying mechanism. The accompanied break-up of the aggregates is promising as a possible...
Software development: An attainable goal for sustainable economic growth in developing nations: The Nigeria experience
December 2007
Recently, there has been increasing demand in the knowledge and application of quality software to improve the socio-economic growth in Nigeria. This becomes necessary in the face of unique position software products and processes helping to generate revenue in most advanced nations and some developing nations in the world. This paper surveys software development and its impact to both developed and developing nations...
Multiplicity distributions in 24Mg-emulsion collisions at 4.5 A GeV/c.
December 2007
The experimental results of target multiplicity distributions in 24Mg emulsion collisions at 4.5 A GeV/c are reported. The multiplicity distributions of target fragments, the correlations between the multiplicity distributions and the projectile fragments, as well as the correlations between the black and gray fragments are given. A comparison between theory and experiment among24Mg and 16O at various energies...
Prediction and measurement of the elastic modulus of the RCC: Case of the low cement proportioning
December 2007
The Roller Compacted Concrete (RCC), which is presented as an evolutionary technology for a large diversity of applications (Dams, roads...), is considered, like conventional concretes and other construction materials, as an elastic material. The RCC in pavement supports many stresses which involve deformations and reciprocally. The knowledge of the relation between strength and deformation, for a material such as the...
Analysis of street dust for heavy metal pollutants in Mubi, Adamawa State, Nigeria
November 2007
This study is aimed at determining the elemental concentrations of heavy metal pollutants that may be present in street dust samples in Mubi, Adamawa state, Nigeria. Dust samples were collected in mechanical workshops (MWK), motor parks (MPK), market areas (MKA), roundabouts/highways (RHW) and residential areas (RDA). The dust samples were digested using aqua regia digestion method and Flame Atomic Absorption...
Preliminary evaluation on the application of grafted membranes for sorption of lead and copper ions in aqueous solution
November 2007
Blend membrane of sodium alginate (Na-Alg) and poly (acrylamide) grafted konkoli gum (KG-g-PAAM) in the ratio of 80:20 was studied for sorption of Pb2+ and Cu2+ in aqueous solution. Membrane sorption capacities for Pb2+ and Cu2+ were found to be 99.18% and 63.32% respectively. The sorption behavior with respect to contact time, initial pH, temperature, ionic strength and initial metal ion...
Isotherm and thermodynamic studies of the biosorption of copper (II) ions by Erythrodontium barteri
November 2007
The biosorption of Cu(II) from dilute aqueous solution using Erythrodontium barteri as a biosorbent has been studied as a function of pH, contact time and initial Cu(II) ion concentration at the temperature of 27oC. The residual Cu(II) in solution was determined using atomic absorption spectrophotometer. The pH study shows that pH dependence of biosorption and optimum pH was 5. The study...
Enhanced measured synchronization of unsynchronized sources: inspecting the physiological significance of synchronization analysis of whole brain electrophysiological recordings
November 2007
The analysis of synchronization, particularly phase locking, is being increasingly used in neuroscience to explore coordinated brain activity. The application of this methodology to magnetoencephalographic (MEG) and electroencephalographic (EEG) recordings would seem promising because these two recording techniques are not invasive and have great temporal resolution. However, current methods of synchronization analysis...
Diversifying Nigeria’s Petroleum Industry
October 2007
The petroleum industry in Nigeria has brought unprecedented changes to the Nigerian economy, particularly in the past five decades when it replaced agriculture as the cornerstone of the Nigeria economy. The oil industry has risen to the commanding heights of the Nigerian economy, contributing the lion share to gross domestic product and accounting for the bulk of federal government revenue and foreign exchange earnings...
The effects of petroleum exploration and production operations on the heavy metals contents of soil and groundwater in the Niger Delta
October 2007
Soil and water samples obtained from four sampling points; around an oil well head, flare site, waste pit and effluent discharge point in an exploration area in the Niger Delta were analysed for their heavy metals contents. The results showed that the amount of lead present in the soil ranges from 3.40 – 99.40 mg/kg, copper values were in the range of 5.10 – 49.30 mg/kg, Nickel concentration vary...
Covariance transformations for flame-propagation modeling
October 2007
The covariance transformation used in earlier theoretical studies of turbulent-flame and isothermal-front propagation is defined and mathematically derived. This transformation provides the covariance associated with fluctuations of a turbulent scalar or vector-component variable in terms of the statistical properties of another fluctuating scalar or vector-component variable when the Fourier transforms of the two...
Effect of the rotation matrix factorization on the quality of images rotation
October 2007
Most efficient algorithms for rotating 2D images are based on the succession of three translations, following the lines, then the columns and the lines of the image again (LCL). These translations result from the decomposition of the rotation matrix into a product of an upper triangular matrix, a lower triangular matrix and an upper triangular matrix (ULU). We have shown in this paper that the decomposition of the...
Concentrations of residues from organochlorine pesticide in water and fish from some rivers in Edo State Nigeria
September 2007
The levels of organochlorine pesticide residues in water and fish from some rivers in Edo State were determined. The water samples were extracted with 15% diethyl ether in hexane, the extracts were treated with copper tunings for the elimination of sulphur interference and analyzed using a gas chromatograph fitted with an electron capture detector. In all the water samples analyzed, the organochlorine pesticide residues...
Effect of urea formaldehyde viscosity on some physical properties of a composite from reactive blending of urea formaldehyde with natural rubber
September 2007
In this work, the effect of urea formaldehyde (UF) viscosity on a composite derived from reactive blend-ing of UF with natural rubber (NR) was investigated. Some physical properties of the urea formal-dehyde-natural rubber (UF-NR) obtained at different UF viscosities (2.1-256.3mPa.s) were evaluated. The melting point, refractive index, density and formaldehyde emission were found to increase with increase in UF...
Evaluation of soil profile on aquifer layer of three locations in Edo state
September 2007
This investigation was carried out in three locations (Ekpoma, Irrua, and Uromi) all in Esan central and North-East region respectively of Edo state, Nigeria. The aim was to find out how soil profile depth is related to aquifer layer. Verifying how relief and (physical properties) such as heat, temperature, and resistivity affects the aquifer layer. Result of the study proved that location, relief, and the factors, such...
Registration of totally aliased signals
September 2007
In this paper, we present a new method for signal reconstruction from multiple sets of samples with unknown offsets which can be written as a set of polynomial equations in both the unknown signal coefficients and the offsets. The solution can then be computed using Groebner bases. In any practical setting, the samples are corrupted by noise, and then there is no algebraic solution. Thus, the next step is to address...
Removal of chromium from an aqueous solution using Azadirachta indica (neem) leaf powder as an adsorbent
August 2007
In the present investigation, Azadirachta indica (neem) leaf powder is used as an adsorbent for the removal of chromium from aqueous solutions. The equilibrium studies are systematically carried out in a batch process, covering various process parameters that include agitation time, adsorbent size and dosage, initial chromium concentration, volume of aqueous solution and pH of the aqueous solution. Adsorption...
Free chlorine residual content within the drinking water distribution system
August 2007
This paper explains the principle of chlorination and reveals the free chlorine residual content within a drinking water distribution system located in peninsular Malaysia. The study found that the free chlorine at user points was slightly greater than 0.3 mg/l, which is higher than the WHO standard at 0.2 - 0.3 mg/l. Despite that it was not a guarantee to lower the level of the microbial since the results showed that...
Pollution profiles of non-metallic inorganic and organic pollutants of drinking and potable waters due to mining activities in Ishiagu (Ebonyi State) of Nigeria
August 2007
The pollution of drinking and potable water sources due to mining activities in Ishiagu District of Ebonyi State of Nigeria, by non-metallic inorganic and organic pollutants was investigated. Water samples were abstracted from the Ivo River (IR), Ishiagu Central School borehole (IB), Amaokwe General Hospital borehole (AB), Amaeke community well (AW1) and Amata community well (AW2). The Ivo River courses through the...
Isotherm and thermodynamic studies of the biosorption of Cd(II) from solution by maize leaf
August 2007
The removal of Cd(II) from dilute solutions using maize (Zea mays) leaf as the biosorbent was studied. The effects of pH, contact time and initial metal ion concentration on the biosorption were monitored. The residual Cd(II) in solution was determined using atomic absorption spectrophotometer. The biosorption was found to be pH-dependent and the optimum pH for the biosorption was pH 3. The biosorption was also...
Synthesis and molluscicidal activity of some new substituted-furan and furo[2,3-d]pyrimidine derivatives
August 2007
1-benzoyl-3-bromo-2-phenylpropenedinitrile derivative 1 reacted with potassium hydroxide to afford the furan derivatives 4 and 5. The furan derivative 5 reacted with formamide, phenyl isothiocyanate, malononitrile, and trichloroacetonitrile to afford the furo[2,3-d] pyrimidine derivatives 6, 8, 11 and 16 respectively. The reaction of 5 with ethyl cyanoacetate afforded however the furo[2,3-b]pyridine derivative...
A robust nonlinear observer for states and parameters estimation and on-line adaptation of rotor time constant in sensorless induction motor drives
August 2007
This paper presents a robust non linear observer for variables and parameters estimation in sensorless Indirect Field Oriented Control (IFOC) of induction motors (IM). Based on the reduced order of the IM model, the rotor fluxes and time constant are estimated with the High Gain Observer (HGO) using only the stator currents and voltages. This reduced order model offers many advantages for real time identification and...
Influence of electroporation on matrix metalloproteinases (MMPs) pattern activity in malignant glioma cells propagated ex vivo
August 2007
Cells exposed to short and intense electric pulses become permeable to a number of various ionic molecules. This phenomenon was termed electroporation or electropermeabilization and is widely used for in vitro drug delivery into cells and gene transfection. The present work is a trial to study the effect of single exponential pulsed electric field (PEF) using intensity range 0.3 to 5.7 KV /cm and 1 m sec...
Levels of essential micronutrients in soils and growing plants around refuse dumpsites in Akure, Nigeria
July 2007
In the present study, the levels of some essential micronutrients (Fe, Mn, Zn and Cu) were determined in the soils and growing plants at the base and 25 m away from refuse dumpsites located in Akure, Ondo state, Nigeria. The soils and plants obtained were processed and analysed for these metals using the Bulk scientific GVP 210 atomic absorption spectropho-tometer. The results showed that the levels of Fe in soils at...
The effect of moisture imbibition on cellulosic bast fibres as industrial raw materials
July 2007
The moisture imbibition on four Cellulosic bast fibres, Roselle (Hibiscus Sabdariffa), Okra (Hibiscus esculentus), Baobab (Adansonia digitata) and Kenaf (Hibiscus Cannabinus), were investigated. The fibres were chemically purified by retting, scouring, bleaching and mercerizing. Thereafter, moisture sorption method was adopted. The moisture imbibition ranking of the fibres is in the...
Study of some physical properties of urea formaldehyde and urea proparaldehyde copolymer composite for emulsion paint formulation
July 2007
Copolymerization of urea formaldehyde (UF) and urea proparaldehyde (UP) was successfully carried out. Physical properties which include gel time, viscosity, density, melting point, moisture uptake, refractive index and formaldehyde emission level were evaluated. The infrared analysis of the pure amino resins and their copolymer (UF + UP) showed chemical interaction between UF and UP resins. Resin from the copolymer...
Adsorption of lead ions from aqueous solution by okra wastes
July 2007
Okra wastes from food canning processes were used as a potential adsorption of lead removal from various aqueous solutions was performed. Parameters such as pH, temperature of the solution, particle size of okra wastes and the concentrations of adsorbent and adsorbate were studied to optimize the conditions to be utilized on a commercial scale for the decontamination of effluents using a batch adsorption technique....
On asymptotic behaviour of a second order delay differential equation
July 2007
In this paper, the relation between the oscillatory behavior of the solutions of second order differential equation and the oscillatory behaviour of the solutions of the corresponding delay differential equation is established. Also a necessary and sufficient condition for every bounded solution of the delay differential equations to have nonooscillatory solutions is given. A.M.S.C.: 34C10, 34C11,...
Effect of temperature on the solubility of haemoglobin modified with acetyl-3,5-dibromosalicylic acid
June 2007
Haemoglobin A was acetylated using acetyl-3,5-dibromosalicylic (dibromoaspirin). The acetylated haemoglobin showed enhanced solubility compared to the unmodified haemoglobin and its solubility was found to increase with temperature in the range 13°-37°C. From the plot of log solubility against the reciprocal of temperature, the DH° was calculated to be 23.74 and 30.06 kJmol-1, for the modified and...
Reservoir fluid differentiation case study from Oredo field in the Niger Delta – Nigeria
June 2007
The formations in the Niger Delta-Nigeria consist of sands and shales with the former ranging from fluvial (channel) to fluviomarine (Barrier Bar), while the latter are generally fluviomarine or lagoonal. These Formations are mostly unconsolidated and it is often not feasible to take core samples or make drill stem tests. Formation evaluation is consequently based mostly on logs, with the help of sidewall samples and...
Image enhancement using second generation wavelet super resolution
June 2007
Second generation wavelet based super resolution algorithms developed in this research are presented in this paper. Generalization of the Second generation wavelet super resolution (SGWSR) algorithm to handle arbitrarily irregular 2-D grids as opposed to the semi-regular grids handled in the previous algorithm is introduced. A consequence is the ability to incorporate the projective camera motion model into the...
Heavy metal pollution and human biotoxic effects
May 2007
Some heavy metals have bio-importance as trace elements but, the biotoxic effects of many of them in human biochemistry are of great concern. Hence, there is the need for proper understanding of the conditions, such as the concentrations and oxidation states, which make them harmful, and how biotoxicity occurs. It is also important to know their sources, leaching processes, chemical conversions and their modes of...
Adsorption kinetics and intraparticulate diffusivities for bioremediation of Co (II), Fe (II) and Cu (II) ions from waste water using modified and unmodified maize cob
May 2007
Heavy metals constitute pollution problems to the environment and they are toxic to both man and aquatic organisms. The passive removal of toxic heavy metals such as cobalt (II) (Co(II)), iron (II) (Fe(II)) and copper (II) (Cu(II)) by inexpensive biomaterials, termed biosorption, requires that the substrate displays high metal uptake and selectivity, as well as suitable mechanical properties for applied remediation...
Completed Beltrami-Michell formulation in polar coordinates
May 2007
A set of conditions had not been formulated on the boundary of an elastic continuum since the time of Saint-Venant. This limitation prevented the formulation of a direct stress calculation method in elasticity for a continuum with a displacement boundary condition. The missed condition, referred to as the boundary compatibility condition, is now formulated in polar coordinates. The augmentation of the new condition...
Global dynamic of a mathematical model of competition in the chemostat
April 2007
The purpose of this paper is to offer a complete global analysis of the behavior of solutions of either the variable - yield two microbial growths, limited by a single scare nutrient, or of competition between two microbial populations for a single limiting nutrient. Basically, we confirm that the variable - yield models make the same predictions concerning the growth of asingle population and...
Implementation of a new 4th order runge kutta formula for solving initial value problems (I.V.Ps)
April 2007
A new method for solving singular initial value problems in ordinary differential equations is developed and implemented using the test problem in (1). Results generated through a FORTRAN program were found to be highly accurate and consistent with minima errors in the solution of some selected singular ivps. A comparison of the results generated from the formula was carried out with other Runge Kutta formulae and were...
Ligand-dependent reactivity of cysF9(93)β of minor duck hemoglobin induced by inositol hexakisphosphate
April 2007
The reactivities of the sulphydryl groups of minor component of duck hemoglobin with 5,51-dithiobis-(2-nitrobenzoic acid), DTNB, in the presence of inositol hexakisphosphate (inositol-P6) have been studied. The reaction has been monitored as a function of pH (pH 7.0 – 9.0) and at ionic strength of 50 mmolL-1. The carbonmonoxy and aquomet derivatives were used for the study. Biphasic time courses were...
A sonar system modeled after spatial hearing and echolocating bats for blind mobility aid
April 2007
This paper present a sonar system modeled after human spatial hearing and echolocating bats. It’s composed of three transducers, one transmitter which plays the role of the mouth of the bat that transmits echolocating signal and two receivers located respectively near the left ear and the right ear so as to mimic human ears configuration. Inaudible ultrasound echoes captured at the receivers are converted into...
Determination of some trace metal levels in Asa river using AAS and XRF techniques
March 2007
The determination of Fe, Mn, Pb, Zn, Cr and Cu concentrations in Asa River using Atomic Absorption Spectrophotometery (AAS) and X – ray fluorescence (XRF) is discussed. Statistical analysis showed there was no significant difference in the concentrations of Cr, Zn, Pb and Cu using the two techniques but significant differences were observed at 5% probability level for Mn and Fe. This was attributed to differences...
Characterization and physicochemical treatment of wastewater from rubber processing factory
March 2007
Wastewater collected from rubber processing factory was characterized for their pollution characteristic. Results of the analysis show that the total solids, TS, suspended solid, SS and dissolve solid, DS, were 1528.5, 1078.5 and 450 mg/l respectively, the turbidity was 702 FTU. These values are high when compared to Federal Environmental Protection Agency (FEPA) effluent discharge standard for industrial wastewater....
Spectrophotometric study of the solution interactions between riboflavin, sodium salicylate and caffeine
March 2007
The self-association of Vitamin B2 (Riboflavin, RBF) and its hetero-association with Sodium Salicylate (NAS) and Caffeine (CAF) have been studied in aqueous solution by UV-Vis spectrophotometry. Using modified Benesi-Hildebrand approach equilibrium hetero-association constants were obtained for RBF-NAS [K = (25 ± 4) M-1] and RBF-CAF [K = (69 ± 4) M-1] systems at T = 298K....
Photocatalytic degradation of methyl orange in aqueous TiO2 under different solar irradiation sources
March 2007
The main causes of surface water and groundwater contamination are industrial discharges. Updating the field of polluted water treatment by photochemical technique has led to an important in oxidative degradation processes applying solar photochemical methods using crystal TiO2 as a catalyst. Photocatalytic oxidation of methyl orange dye under different irradiation sources (Halogen lamp 1000 W, fluorescent lamp and...
Environmental effect of mineral exploitation in Nigeria
February 2007
The three stages of mineral development, viz exploration, mining and processing, have caused different types of environmental damages, which include ecological disturbance, destruction of natural flora and fauna, pollution of air, land and water, instability of soil and rock masses, landscape degradation and radiation hazards. The environmental damage has in turn resulted in waste of arable land, as well as economic...
Effect of coconut fibre filler on the cure characteristics physico–mechanical and swelling properties of natural rubber vulcanisates
February 2007
Investigation into the effect on the rheological, physico – mechanical and swelling properties of natural rubber vulcanizates using coconut fibre as fillers were carried out. The coconut fibre was characterized in terms of pH, moisture content, ash content, loss on ignition, conductivity, particle size and surface area. The physico – mechanical properties as well as the equilibrium swelling characteristics...
Utilization of coconut fibre carbon in the removal of soluble petroleum fraction polluted water
February 2007
Activated carbon powder was obtained by treating coconut fibre with ammonium chloride and carbonized at 400oC. The powdered activated carbon was sieved. The portion that passed through a 212 um and retained on a 90 um mesh size was used for this study. The treatment was done to increase the surface area and the adsorption site of the carbon. The activated carbon was characterized in terms of pH, surface area, loss on...
Some electromagnetic transition properties and mixing ratios of tellurium isotopes
February 2007
IBM-2 calculation is presented for the low-lying states in the even-even 122-128Te core nucleus. We developed the projection by using the F-spin formalism from the operator of IBA-2 model over the operator of IBA-1 model space. With the help of this projection IBA-2 Hamitonian parameters are obtained and we explore the energy levels and the electric quadrupole transition probabilities B...
Patient dose reduction methods in computerized tomography procedures: A review
January 2007
Health hazards are associated with medical exposures to ionizing radiation, including during Computed Tomography (CT) procedures. Rapidly increasing number of CT facilities worldwide is accompanied by enhanced staff, patient and public radiation doses and these needs to be controlled to minimize health risks. This paper reviews the relevant patient and CT scanning parameters that influence patient dose during the common...
Comparative study on the adsorption kinetics and thermodynamics of dyes onto acid activated low cost carbon
January 2007
Batch experiments are carried out for the sorption of Congo red, Malachite green and Rhodamine B dyes onto acid activated carbon. The operating variables studied are initial dye concentration, pH, temperature and contact time. The equilibrium data are fitted to the Langmuir and Freundlich isotherm equations. From these the adsorption efficiency, adsorption energy, adsorption capacity, intensity of adsorption and...
Precision of sensitivity in the design optimization of indeterminate structures
January 2007
Design sensitivity is central to most optimization methods. The analytical sensitivity expression for an indeterminate structural design optimization problem can be factored into a simple determinate term and a complicated indeterminate component. Sensitivity can be approximated by retaining only the determinate term and setting the indeterminate factor to zero. The optimum solution is reached with the approximate...
Deterioration and corrosion in scoria based blended cement concrete subjected to mixed sulfate environment
December 2006
The use of blended cements incorporating supplementary cementing materials and cements with low C3A content is becoming common to prevent the deterioration of concrete structures subjected to aggressive environments. This paper presents the results of an investigation on the performance of finely ground volcanic scoria (VS) based ASTM Type I and Type V (low C3A) blended cement concrete mixtures with varying immersion...
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