This general process design for multi-components vapor-liquid equilibrium flash calculation of a two-phase system comprises bubble and dew point calculations, estimation of the flash point, calculations of the vapor split and resulted compositions with flow rates in each of the liquid and vapor phases and estimation of the pre-heat temperature needed for a specific vapor split via unprecedented theories. The technique employed entails prediction of the equilibrium temperature, based on the critical temperatures of the feed’s components, which in turn is used to estimate the corresponding flash pressure. The theories entail accommodate any light hydrocarbons’ mixture and other molecules which are of relatively uncomplicated molecular force fields, as in the case of natural gas liquid. Appropriate gases and liquid properties correlations parameters were obtained from the literatures and used in different equations most suitable for vapor-liquid equilibrium calculations of any light hydrocarbons’ mixture and other mixtures of relatively uncomplicated molecular force fields. The computer implementation puts forward for this design calculation, which can handle up to twelve components, aids the calculations of vapor-split, which requires several iterations, and other results.
Aims: This study was performed to assess the effects of N-methyl-N-nitrosourea (MNU) on the hematology and histology of selected organs in albino mice. Study Design: Eighty male and female mice, eight-week old, were subdivided into four groups of twenty each. Place and Duration of Study: Department of Zoology, University of Ibadan between January and July 2011. Methodology: Forty male and female mice received a single dose of 50mg/kg MNU in 1mL of 0.9% Nacl via intra-peritoneal injection. One mouse from each group was sacrificed each month and processed using standard histological techniques. At the end of the study, blood samples collected from two mice per group were processed using standard hematological procedures. Results: MNU induction impacted different morphological abnormalities in induced mice: vacuolization (small intestine), multi-nucleation (spleen, liver), cytoplasmic pallor (heart, liver), increased lymphocytic activity (spleen, thymus), necrosis (heart, liver), and destruction of intestinal wall (small intestine). Increased nuclear-cytoplasmic ratio, nuclear pleomorphism, enlarged nuclei sizes and cytoplasmic degeneration were also common features observed. One of the induced mice developed a neck tumor eight weeks after induction. The histological section of the tumor showed complete necrosis. Except for increased nuclei sizes in the liver, these abnormalities were not observed in control mice. Hematological analysis did not show any significant differences (p=0.05) in packed cell volume, hemoglobin, red blood cell count and monocytes between the induced and control mice. Conclusion: Exposure to MNU caused varying degrees of abnormalities over a 28-week period in induced mice. The study duration however appeared insufficient for the development of any pronounced hematological effects in induced mice.
In reservoir modeling, making the steady-state policy of the flood control is a challenging task. In this paper, the normal operating heights of a reservoir network is discussed. Initially, the coupled tank system is employed to model the reservoir network. At the equilibrium state, the normal operating heights are then derived analytically. As the linearization is taken, the associated Jacobian matrix, which is a diagonally dominant tridiagonal matrix with negative diagonal entries, is obtained. Because of the negative eigenvalues of this matrix, the stability condition of the reservoir network can be made. For illustration, the different rain rates are used to calculate the surface area of the reservoir and the corresponding normal operating heights of the reservoir are then determined. The result obtained shows the stability of the reservoir. In conclusion, the approach discussed is efficient to the decision making on the stability of a reservoir network.
Aims: To assess the influence of human-induced disturbances on bird communities. Study Design: Longitudinal study. Place and Duration of Study: Four forests; - Kion/Zaraninge, Kwamsisi/Kwahatibu, Msumbugwe and Gendagenda in Pangani–Saadani ecosystem, from October 2010 to January 2011. Methodology: Eight permanent transects, each 500 m long stratified into forest core and forest edge habitats were used in each forest to identify types and quantify levels of human-induced disturbances, determine bird species composition, diversity and richness, and abundance. Therefore three circular plots, each 20 m radius were allocated at beginning, middle and end of each transect. The level of disturbance was assessed using four disturbance indicators; tree lopping, human trails, Pit-sawing and animal snaring while bird species were identified by sight and call. One-way Analysis of Variance was used to test for differences in bird abundance between forests. Moreover, Shannon-Wiener Diversity Index (H’) was calculated for each forest to assess species diversity and evenness, and Bray-Curtis Cluster analysis was used to determine similarity in bird species composition between the forests. Results: A total of 564 individuals composed of 88 bird species distributed in ten Orders were recorded. The level of Pit-sawing and lopping differed significantly between forests (P<.05) with Msumbugwe being more disturbed than the rest. Bird abundance differed significantly between the forests (P<.05) with the highest abundance occurring in Msumbugwe. As expected, species richness and diversity were greater in least disturbed forests-Kiono/Zaraninge and Kwamsisi/Kwahatibu than in the highly disturbed forest, but forest dependent species were not significantly different between the study forests. Apparently, only Pit-sawing was found to correlate with bird abundance (P<.01) whereas similarities in species composition were evident with Kion/Zaraninge and Gendagenda exhibiting much overlap. Conclusion: Increasing forest disturbances seems to negatively impact on distribution of birds thus challenging conservationists to devising sustainable forest management strategies in order to sustain bird diversity and abundances in these unique forests.
Sediment samples taken from eight locations within the Owena Multi-purpose Dam in six sampling campaigns, covering the wet and dry seasons were analyzed for Pb, Cd, Cu, Cr, Ni, Fe, Mn and Zn using the atomic absorption spectroscopic method. Samples of three fish species: Clarias gariepinus, Clarias anguillaris and Oreochromis niloticus collected from the dam were also analysed for the above metals concentration. Results of heavy metals determination revealed significant seasonal variation (P = .05) in most measured parameters, while spatial variation was not significant. Generally, the results indicate that the measured parameters of the dam sediment were far lower than the Probable Effect Concentrations (PEC). Also, all metals monitored were detected in all the fish samples except cadmium that was not detected in the trunk of Oreochromis niloticus. They, however, showed values that were within the acceptable International Standards in fish for human consumption and so, could not presently cause any health hazard. The present study has produced vital information about the current status of the dam, which would also serve as a baseline for future monitoring of the dam.
Sediment; heavy metals; Owena multi-purpose dam; fish; coefficient of variation
The Darrieus Vertical Axis Wind Turbine is a versatile method of generating power in the Caribbean. The cost, reliability and power produced are of paramount importance in the success of these wind turbines. This study analyzed different methods of improving the output power of a Vertical Axis Wind Turbine. In the case study a Vertical Axis Wind Turbine was built using the NACA 0018 airfoil type for the blade profile. The turbine consisted of three blades of length 3.05 meters and had a diameter of 6.10 meters. Experimental results showed that drag reduction on the strut arms of the blades increased the power output greater than any other method tested. The Vertical Axis wind turbine power output increased by approximately 27% in some cases using a strut modifier to decrease the drag component of the blade’s strut.
Accurate prediction of fluid properties is essentials for all reservoir engineering calculations such as estimation of reserves, well testing analysis and in numerical reservoir simulation. Oil formation volume factor is one of the properties that can either be gotten from empirical or experimental method. This work focuses on the use of fuzzy sequential forward techniques to develop a oil formation volume factor model using 1,316 data obtained from 45 different oil fields in the Niger Delta, Nigeria. The data set was randomly divided into two parts with 750 used for training and 566 for testing. The model developed has the lowest Root Mean Square Error (RMSE) of 0.0784 when compared with published correlation used for prediction. The accuracy of the developed model was tested with cross plot and statistical analysis. The model developed outperformed the existing correlations when subjected to further statistical analysis.
Aims: This paper provides an in-depth description of lightning risk analysis and related protection standards as an introductory guideline to alert microgrid (MG) designers and provide basic understanding of the lightning phenomena as well as designing effective protection techniques. Study Design: Computer-simulated models for protecting MG components have been developed in order to obtain data and check the validity of the proposed solutions. Place and Duration: This study was carried out in Ottawa, Ontario, Canada during the period of January 2011 to January 2012. Methodology: Models are developed using the graphical environment of MATLAB and PSCAD corresponding to a proposed MG at the University of Ottawa campus. As part of lightning risk management, two simplified lightning preventive techniques are considered: a MG and related distribution network taking into account the presence of transformers and the surge transfer through transmission lines within the MG environment. Conclusion: It is concluded that: (1) placing one or more shielding wires on a rooftop is an inexpensive yet reliable way to provide lightning protection for a MG environment; and (2) right surge arrester needs to be chosen for each application in order to have sufficient operating voltage and a surge current voltage low enough to keep the MG transformers and distribution lines safe.
Weed species examined as alternate hosts implicated Panicum maximum Jacq as the most abundant host of vector insects of the lethal yellowing disease (LYD) of coconut palms. Ten weed species out of the 19 examined hosted leaf hoppers Cicadellidae and plant hoppers Flugoroidea. They were found in inner leaf sheaths and leaflets. The weed species in coconut LYD areas recorded abundance of Cicadellidae and Flugoroidea species with Panicum maximum 32.7%, Andropogon gayanus 23.6%, Sorghum arundinaceum 13.4%, Cyperus difformis 12.4% and Oryza barthii 11.2%. Weed species in coconut non-LYD areas recorded relatively low abundance with P. maximum 9.1%, A.gayanus 8.4%, Leptochloa filiforms 6.8%, and S. arundinaceun 2.8%. Eggs, nymphs and adult Cicadellidae and Flugoroidea species were excised from these weeds mainly grasses. The under-story canopies of coconut palms LYD temperature at 26 ± 2ºC made the vegetation cool, conducive and environmentally friendly for mass breeding when compared with non LYD areas at 32 ± 2ºC. The insects were found on the canopies of LYD coconut palms up to late in the evening (7:00 p.m.) and early in the morning (6:30 a.m.). Some of the Flugoroidea species were observed with the proboscis pointed down to the leaf surface with streak damages, an indication of feeding and nesting. Frequencies occurrence of Cicadellidae and Flugoroidea species proved that abundance of decaying palm logs, pruned fronds, spathes and inflorescence were reservoir for mass breeding. This development could predispose coconuts to series of infections and possible transmission of LYD to healthy coconut palms.
We investigate a locally similarity solution of unsteady natural convection heat and mass transfer boundary layer flow past a flat porous plate. The effects of chemical reaction rate and Arrhenius activation energy on the velocity, temperature and concentration are also studied in this paper. The governing partial differential equations are reduced to ordinary differential equations by introducing locally similarity transformation Maleque . Numerical solutions to the reduced non-linear similarity equations are then obtained by adopting Runge-Kutta and shooting method using the Nachtsheim-Swigert iteration technique. The results of the numerical solution are then presented graphically in the form of velocity, temperature and concentration profiles. The corresponding skin friction coefficient, the Nusselt number and the Sherwood number are also calculated and displayed in Table showing the effects of various parameters on them.
Aims: The present work aims to determine the toxicity of Chloroanilines isomers and evaluate the effect of Chloroanilines isomerism and intramolecular hydrogen bonds on inhibition of methane biosynthesis by the acetoclastic methanogenic bacteria. Study Design: Anaerobic digestion of pig manure, anaerobic toxicity essay, Effect of the isomerism (functional groups position) on inhibition of methane biosynthesis by the methanogenic bacteria), Correlation of the methanogenic toxicity (IC50) with Chloroanilines boiling point. Place and Duration of Study: Department of Chemistry, University of Kinshasa, DR Congo, between April 2011 and March 2012. Methodology: The toxicity to acetoclastic methanogenic bacteria was performed with the standard method of serum bottles; digested pig manure was utilized as inoculums and acetate as substrate. The methane gas volume produced was measured by serum bottles liquid displacement systems (Mariotte flask system). Results: The obtained results indicate there are relationships between the isomerism of Chloroanilines and their inhibitory effects on methanogenic bacteria. The various isomers of Chloroaniline have toxicities which are different from 51.00; 539.78 and 787.47 mg / l respectively for the ortho, meta and para-Chloroaniline. One can notice that the o-Chloroaniline IC50 value is 10.43 and 15.44 times more toxic than meta and para Chloroaniline respectively. Contrary to all predictions, it is more toxic than benzene. This behavior can be explained by the formation of a strong hydrogen bond between the electronegative chlorine atom (-Cl) and amino group (-NH2) in o-Chloroaniline in ortho position of aromatic ring. The formation of this intramolecular bond decreases the steric hindrance of this isomer and increases its mobility (diffusion coefficient) to the cell membrane). A significant linear correlation was found between the IC50 values of Chloroanilines isomers and their boiling temperatures. Conclusion: The results obtained in this paper indicate that some relationships exist between the isomerism (functional groups position) of Chloroanilines and their inhibitory effects on methane biosynthesis by the methanogenic bacteria. The formation of a very strong intramolecular hydrogen bonds between chlorine atom and amine group renders ortho Chloroaniline very toxic than the others tested Chloroaniline isomers.
A joint optimal policy for the vendor and the buyer is analyzed when units in inventory are subject to deterioration and demand is trapezoidal. It is shown numerically that the joint venture reduces the total joint cost significantly when compared with the independent decision of both the players. To entice the buyer to place orders of larger size, a permissible credit period is offered by the vendor to the buyer. A negotiation factor is incorporated to share the benefits of cost savings.
This work was aimed at determining the effects of planting date on the yield and proximate composition of pumpkin fruits. The experiment was a randomized complete block design. In the study was used four planting dates (1- 1st of April; 2- 15th of April; 3- 1st of May; 4- 15th of May). The experiment was replicated thrice. Standard analytical methods were used to analyze the fruits for the proximate content. The data collected, were subjected to analysis of variance. Means, where significantly different, were separated using Duncan Multiple Range Test (DMRT) at 5% level of probability. Studies were carried out in year 2007 and 2008 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Osun state, Nigeria, with 4 planting dates each. The yields of the crops planted on the 1st and 15th of April were not significantly different but significantly out-yielded (53.56 and 49.93 tons ha-1 respectively) every other crop planted subsequently. The 1st planting date produced significantly highest protein (17.98 g 100g-1), crude fibre (1.90 g 100g-1) and ash (3.9 g 100g-1), compared to other planting dates. Lesser rainfall, moderately higher temperature and higher sunshine hour were observed to be responsible for the results. In conclusion, early planting (April) or planting at the onset of rainfall will bring about optimal yield and food value of pumpkin at the location where this experiment was conducted (rainforest tropical region).
Aims: The study is aimed to evaluate the concentration of trace elements and irrigation quality of the groundwater of Winder, Balochistan, Pakistan. Study Design: The ophiolitic rocks of the study area upon weathering, contributed a large amount of certain trace elements to the groundwater. Samples of groundwater were collected and analyzed for trace elements. Place and Duration of Study: The study area lays in the southern extremity of 450km long Bela Ophiolite, Balochistan, Pakistan. The work was carried out during 2011-2012. Methodology: Sample collection and estimation of physical properties and chemical composition of water were carried out using standard procedures. The concentrations of trace elements were estimated by using Atomic Absorption Spectrophotometer. Results: The trace elements concentration in the groundwater were found in the range of 8-800 for Zn, 14-107 for Cu, 13-103 for Cr, 32-1814 for Fe, 15-102 for Mn, 01-430 for Ni, 01-28 for Co, 16-139 for Pb and 1-30mg/kg for Cd. Conclusion: The present study revealed Fe>Ni>Zn>Pb>Cu>Cr>Mn>Cd>Co trend of abundance. Bivariate and ternary plots suggested alliance with the nearby exposed rocks. The statistical analysis of the trace elements data in form of correlation matrix and principal component analysis (PCA), further verify dissolution of trace elements from ophiolitic and sedimentary rocks. The concentration of trace elements of the groundwater is discussed in relation to biological function in the plants and found within the safe range as compared to the permissible limit for irrigation purpose.
This paper covers not linear differential equations (LDE) with variable coefficients but respective Riccati type equations which play a similar role to a characteristic equation during integration of LDE with constant coefficients. We have established a certain analogy of problems of integration of LDE in quadratures with a problem of solution to algebraic equations with radicals [5,6,7,8]. Necessary and sufficient condition for existence of an eλx form solution to an LDE of the n-th order with variable coefficients has been found. At the end of this paper we give specific examples. The solutions of this method can be used in the studies of properties of thermal conductivity, hydrophobicity of composite materials, development of new technologies multilayer asphalt and three-layer wall panel of heterogeneous materials.