Aims: The present case study is on maximizing the aqua feed properties using response surface methodology and genetic algorithm. Study Design: Effect of extrusion process variables like screw speed, L/D ratio, barrel temperature, and feed moisture content were analyzed to maximize the aqua feed properties like water stability, true density, and expansion ratio. Place and Duration of Study: This study was carried out in the Department of Agricultural and Food Engineering, Indian Institute of Technology, Kharagpur, India. Methodology: A variable length single screw extruder was used in the study. The process variables selected were screw speed (rpm), length-to-diameter (L/D) ratio, barrel temperature (ºC), and feed moisture content (%). The pelletized aqua feed was analyzed for physical properties like water stability (WS), true density (TD), and expansion ratio (ER). Extrusion experimental data was collected by based on central composite design. The experimental data was further analyzed using response surface methodology (RSM) and genetic algorithm (GA) for maximizing feed properties. Results: Regression equations developed for the experimental data has adequately described the effect of process variables on the physical properties with coefficient of determination values (R2) of > 0.95. RSM analysis indicated WS, ER, and TD were maximized at L/D ratio of 12-13, screw speed of 60-80 rpm, feed moisture content of 30-40%, and barrel temperature of ≤ 80ºC for ER and TD and > 90ºC for WS. Based on GA analysis, a maximum WS of 98.10% was predicted at a screw speed of 96.71 rpm, L/D ratio of 13.67, barrel temperature of 96.26ºC, and feed moisture content of 33.55%. Maximum ER and TD of 0.99 and 1346.9 kg/m3 was also predicted at screw speed of 60.37 and 90.24 rpm, L/D ratio of 12.18 and 13.52, barrel temperature of 68.50 and 64.88ºC, and medium feed moisture content of 33.61 and 38.36%. Conclusion: The present data analysis indicated that WS is mainly governed by barrel temperature and feed moisture content, which might have resulted in formation of starch-protein complexes due to denaturation of protein and gelatinization of starch. Screw speed coupled with temperature and feed moisture content controlled the ER and TD values. Higher screw speeds might have reduced the viscosity of the feed dough resulting in higher TD and lower ER values. Based on RSM and GA analysis screw speed, barrel temperature and feed moisture content were the interacting process variables influencing maximum WS followed by ER and TD.
This study was carried out to establish the effect of “Ionic Soil Stabilizer 2500” (ISS 2500) on black cotton soil. Samples were collected along Dikwa–Gamboru Ngala road in North-East Nigeria. Initial results indicated that the black cotton soil could be expansive with over 60% passing the number 200 sieve size. The ISS stabilizer is 100% organic and is derived from combined organic Sulphur and buffered acids that are combined as bi-sulphates. The ISS stabilizer dosages of 0%, 1ml, 2ml, and 3ml were mixed with 6000g weight of black cotton soil and tests were carried out to determine if improvement in properties would occur. For the pH tests carried out, there were increases in the acidity of the samples with increase in ISS content. Similarly, the redox potential showed consistent increase in value with increase in ISS content. However, the plasticity index which was expected to decrease in view of the increases in the redox potential, and the electrical conductivity decreased instead. The CBR test was conducted in accordance with energy levels using British light compaction method. Consequently, the CBR values increased marginally but below the specifications for soil-cement stabilization for road base materials. The ISS stabilizer has not produced a consistent set of results for inferences to be made on its effectiveness in improving the properties of black cotton soils to road base standards. Further tests are required on the long term effects of the stabiliser on black cotton soils.
Aims: Thermal cracking of waste plastic (without catalyst) to useful chemicals. Study Design: To design the experimental procedure, we primarily concentrated on the thermal stability of the materials by bearing in mind the results of thermogravimetric analysis (TGA). Based on the thermogravimetric results the appropriate set-up for the decomposition of the plastic wastes was designed. Three common household plastic wastes – styrofoam dining plates (SDP), shipping protection styrofoam boxes (SPFB), and carrying plastic shopping bags (CPB) – were pyrolized into liquids. GC-MS was used to characterize the sample of the obtained liquids. Place and Duration of Study: The study was done in the Department of Biological and Physical Sciences at South Carolina State University (SCSU), Orangeburg, SC, USA, during the summer of 2012. Methodology: The thermal cracking process without catalyst was used to convert household waste plastics into liquids. Three types of waste plastics, SDP, SPFB and CPB were used for these studies. The waste plastics were cut into small slices suitable to fill the reactor. Prior to pyrolysis, the thermal stability of materials were determined by thermogravimetric analysis (from 70ºC to 650ºC) with a heating rate of 10ºC/min while the samples were purged with 10 mL/min argon. The condensed liquids were analyzed by a Shimadzu GC-MS model GCMS-QP 2010s using helium as the mobile phase. Results: The thermal stability of waste plastics depended on the nature of constituent polymers from which the plastic originated, as was expected. Polystyrene derivatives, SDP and SPFB, both physically soft and hard, had similar thermal stability. The highest decomposition rates were observed at temperatures 418ºC and 423ºC for soft and hard SPFB respectively. No leftover was observed by thermogravimetric analysis. SDP were thermally more stable than SPFB; the decomposition began around 400ºC. The highest weight loss rate was observed at 440ºC. The TGA leftover was about 3% of total mass of SDP. The bulk pyrolysis of SDP and SPFB had 20% to 30% leftover. The GC-MS chromatogram indicated that over 350 chemicals resulted from decomposition of polystyrene based materials; the most abundant compound of pyrolysis was styrene and styrene derivatives as expected. The pyrolysis of CPB yielded hydrocarbons C4 to C24 being both alkanes and alkenes as expected. The TIC picks of CPB were geminals; first being alkene and the next was alkane with the same number of carbons (Figure 9). Conclusion: The chemical composition of the liquids obtained and the yields depended on the original polymer, quality of the waste, and the engineering of thermolysis procedure. The refinement of liquids resulting from pyrolysis is necessary to obtain a quality fuel. The condensed liquids produced from pyrolysis contained highly reactive chemicals such as vinyl, alkene, and three- and four-member cyclic hydrocarbons, which make the storage life of these materials short. For long time storage, however, these liquids must be stabilized either by stabilizers or hydrogenation of the product promptly after collection.
Aims: The effects of oven – drying (OVD), brining and oven – drying (BOVD) and smoking (SMK) on quality and shelf – life of Catfish (Chrysichthys nigrodigitatus) and Tilapia(T. zillii) were evaluated. Study Design: Completely randomised block design. Place and Duration of Study: Department of Environmental Management & Toxicology, Federal University of Agriculture Abeokuta, Nigeria, between February 2011 and August 2012. Methodology: Life fish were collected and processed using three local preservation methods. Processed fish samples were stored in perforated plastic containers for 11 successive weeks at ambient temperature (25-32ºC) and assessed weekly for weekly for levels of trace metals (Fe, Zn, Cd, Pb) and physical attributes of odour, flavour and texture. Microbial load was assessed by total viable count (TVC) and biochemical activity by total volatile nitrogen (TVN). Results: This study showed that brined/ oven-dried fish was the most accepted followed by smoked fish. The quality of processed fish under ambient conditions decreased with increasing storage time in the order OVD>SMKD<BOVD. Statistical analysis showed that no significant (P=.05) differences existed between the trace metal contents of the samples from the three processing methods. Also, samples processed using the three processing methods contained levels of trace metals below the recommended limits for trace metals in fish and are therefore safe for human consumption. However, method of processing had significant effects (P=.05) on the TVC and TVN content of fish. Conclusion: Brined/oven dried samples were most organoleptically accepted and deteriorated the least. Chrysichthys nigrodigitatus deteriorated faster in odour and flavour than Tilapia zilli. Caution should be exercised in the consumption of processed fish stored on open shelf for very long weeks (above 5 weeks) as they could contain higher amounts of microbial cells.
The behaviour of the subsurface soil upon application of a low potential field has been investigated utilizing Schlumberger configuration of Electrical resistivity survey. The characteristics of three different soil types which include sandy clay, sand-clayey loam and loamy sand were also investigated through laboratory analysis. The aim was to determine the variation in the subsurface electrical properties such as resistivity and dielectric polarization with the soil texture and structure, density, soil moisture, and mineralogy. The results show variation in electrical resistivity for the different soil types at different depth range points as 1.33 Ω-m to 9.77 Ω-m for sandy clay, 2.09 Ω-m to 23.06 Ω-m for sandy clay loamy and 3.26 Ω-m to 128.0 Ω-m for loamy sand while apparent resistivity increases from 125 Ω-m for sandy clay to 1.448 x 103 Ω-m for loamy sand. The interpreted VES results indicate a variation of resistivity with depth and lithologic units. There is a general increase in both the electrical resistivity and dielectric constant with depth for loamy sand, sand clay loamy and sandy clay as the grain size of the soil mineral decrease with decreasing moisture content and pore space distribution with depth. However, the magnitude of variation of the dielectric constant with compaction are in the order Sandy Clays > Sandy Clay Loamy > Loamy sand. Soils with higher dielectric constants such as Sandy Clay should be more suitable for agricultural farming in tropical areas especially during dry season. The laboratory and field survey studies of rock electrical properties show that both the dielectric constant and soil resistivity increases with depth and density.
The postharvest quality of Jew’s mallow was tested using two types of plastic liners and two temperatures, 4ºC and 10ºC. The plastic liners were normally sealed low density polyethylene and modified atmosphere package. Six quality parameters (weight loss, chlorophyll content, decay level, dryness level, yellowing level and chilling injury) were studied. It was found that Jew’s mallow leaves had a longer shelf life at 4ºC than at 10ºC. Modified atmosphere package liner showed a good result with respect to decay level. The shelf life was two weeks.
Heritability and correlation are the key components while, conducting an experiment for some specific traits on plant breeding. Keeping in view that importance this study was carried out utilizing 10 mungbean genotypes. Field Experimental was conducted in Randomized Complete Block Design (RCBD) with four replications. The parameters studied include, days to flowers initiation (DF), days to pods initiation (DPI), plant height (PH), days to maturity (DM), grain yield plant-1(GY) and 100-grain weight (100-GW). Significant differences (P≤0.01) were observed for DF, PH, DM and 100-GW, while days to pods initiation and grain yield plant-1 showed considerable difference at P≤0.05. Genotype NM-93 took minimum number of days to 50% flowering (42.0 days), days to pods initiation (66.50 days) and days to maturity (78.25). Maximum grain yield was recorded for genotype Ramzan (45.35) while maximum 100-grain weight was recorded for NM-93 (5.85). High heritability was recorded for days to 50% flowering (88.75%), days to maturity (86.29%), 100-grain weight (77.17%) and plant height (67.32%). Low heritability was recorded for days to 50% pods formation (31.72%) and grain yield plant-1 (33.50%). The results revealed that grain yield plant-1 had highly significant phenotypic correlation with days to 50% pod formation (0.60) and with 100-grain weight. Grain yield plant-1 had significant genotypic correlation with days to pods formation (0.70). Therefore, days to flowering, days to maturity and100-grain weight can be recommended as selection indices for high yield and genotypes Ramzan, NM-93 and NM19-19 can be used in further mungbean breeding programmes.
Aims: This study was carried out to determine the groundwater flow pattern in order to identify the converging centres with high yield expectations. Study Design: The study area, Okigwe District in Imo State Nigeria, lies between latitude 5º30′N to 5º57′N and longitude 7º04′E to 7º26′E and covers an area of approximately 1,824 km2. Methodology: One hundred and twenty (120) vertical electrical sounding (VES) results, using the Schlumberger configuration were acquired in order to map the ground water flow pattern within the study area. The maximum current electrode spacing for the survey was 900 m. Results: Twelve of the VES stations were sited near existing boreholes to enhance interpretation. The resistivity of the aquiferous zones varied across the study area ranging from 33.1Ωm obtained at Umuedi (VES 7) in the northern part to 32600Ωm at Otoko (VES 93) in the southern part of the area. Using an average transmissivity of 1032.0848 m2/day determined from pumping test data of the boreholes in the area a mean conductance value of 91.222 m/day was obtained for the area. Analysis of VES data shows that the groundwater flows from the Northern part of the district towards the Southeastern part, South central and South Western parts. It also flows from the South-South area to Southeastern and South central parts of the study area forming two main collecting (converging) centres C1 and C2 having approximately West-East trend. C1 lies within the valleys of Efuru and Eze Rivers while zone C2 lies almost parallel to the Onuinyi River and the Abadaba Lake. Conclusion: The survey results show that the Southern and Northeastern parts of the district are more promising for siting borehole with high yield expectations than the North Western part. The occurrence of aquifer in this area is linked to the presence of fractures in the shale members.
Because of the technical complexities involved in the plasma heating process in most reactions a simple method has been introduced by this author in ITC/12 conference, Japan. In the present approach rather colder plasmas are stimulated by using positronium atoms as stimulus element into the plasma media (The formation of positronium atoms are plausible through injection positrons from Ring storage into plasma media which immediately tends to pair annihilation then leading to gamma emission in singlet and / or triplet forms referred to the spins of pairs (Table 1)). The energy obtained by these rays would thermalize the plasma particles even if they should be used in nuclear reaction. In the present paper the interactions between gamma rays with the plasma particles including electrons, ions and neutral species through different mechanism are investigated, ultimately all interaction cross – sections are taken into account and the possible wall interactions calculated.
Fuel ethanol research development deals with process design integration for improving production of ethanol. This paper investigates the effect of variable reflux ratio on the design of distillation column using developed JAVA based simulation software. This was done by varying reflux ratio as an input parameter and observed the effect it has on the number of trays that produced the column height. Varying reflux ratio arbitrarily from 3.094 to 9.301 produced column height ranging between 5.897 and 6.232 respectively. With the feed composition of ethanol-water mixture set at 45 percent, and the minimum reflux ratio of 3.4. The results showed that the number of trays decreases with increase in reflux ratio while the column height varies inversely with the reflux ratio.
Aims: This paper reports the investigations pertaining to the adsorbability of ferri/ferrous impurities found in commercial grade sodium sulphide (which is not suitable for manufacture of pharmaceutical grade chemicals and dyes chemicals) by using chalk powder as an adsorbent in different proportions in the aqueous solution of commercial grade sodium sulphide. Study Design: Supernatant solution obtained after soda ash treatment of barium sulphide extract contains sodium sulphide as the main by-product. This supernatant solution on evaporation gives flakes of crude sodium sulphide. Place and Duration of Study: This study was carried out in Alwar (Raj.), India and the duration of study was two years. Methodology: All required methods, materials, preparations of reagents and experiments were carried out using standard procedures. Results: It is noted that incorporation of chalk powder reduces the iron contents considerably. Even slight addition (as small as 1%) is sufficient to reduce the contamination of iron contents from 1.50 mg to 0.10 mg. Hence this method had proved to be a cost effective and convenient way for the reduction of iron contents in the contaminated crude sodium sulphide. Conclusion: Based on the above results, it can therefore be concluded that chalk powder is a very good adsorbent. Even using 0.05g of chalk powder reduces the amount of iron from 1.50mg to 0.12mg.The obtained results can be quite useful in industrial practice.
The degradations induced by the external conditions are ordered by defining several classes of exposure for the corrosion risk, depending on the environmental actions and concrete work conditions. Minimal concrete covers requirements are associated with these classes. Among these classes, there is that corresponding to the corrosion induced by carbonation (XC), which applies to the reinforced concrete exposed to the air and moisture The aim of this paper is the evaluation of carbonation time (T1), which is the time necessary so that the face of carbonation arrives until the reinforcement from a probabilistic analysis. Monte Carlo simulations are realized under the assumption that the Water /Cement ratio, the relative humidity, and the pressure of the carbonic gas on the surface of the concrete are random variables with a log-normal probability distribution.
In regions where water is in short supply, wastewater treatment offers the possibility for the efficient removal of unwanted pollutants and germs so that the water may be used for irrigation. Water scarcity is an old problem in Palestine because of various geographical settings and political turbulence. The problem is compounded by population growth and development. As a result of the increasing demand for water, using alternative options has become a must to meet water needs. The demand for water can be reduced by increasing the efficiency of water use and by making usable sources of water previously considered unusable. One possible supply is ‘wastewater’. This project sets out to treat and reclaim wastewater as a supply of irrigation water and thus enhance crop production. The project results reveal that wastewater from the Ateel wastewater station potentially can be used for irrigating crops. It offers many social and financial benefits for improving the farmers’ sources of revenue. Various parameters were monitored and measured for the Ateel wastewater station and yielded some interesting and promising data.
Aims: Use a natural compound derived from cashew nut shell liquid to the production of an additive inhibitor of the oxidation of lubricants oils. Study Design: This article describes the syntheses, characterization and evaluation of the antioxidant action of a phosphorylated compound derivate from hydrogenated cardol (diphenyl phosphorylated-cardol). Place and Duration of Study: Department of organic and inorganic chemistry (Universidade Federal do Ceará), between June 2009 and July 2010. Methodology: Cardol was isolated from hydrogenated cashew nut shell liquid through column chromatography eluted with a stepwise gradient of n-hexane/ethyl acetate. Diphenyl phosphorylated compound was synthesized through of reaction between cardol and diphenyl chloro-phosphate in basic medium. After purification and characterization the performance this compound was evaluated in minerals oils by thermal analyses, monitoring parameters as T(onset), T(endset), T(max) and IPDT, using samples doped in 1 %. Results: The cardol was isolated with 10 % of the yield and the diphenyl phosphorylated compound was synthesized with a yield of 61,4 %. The techniques of characterization (GC/MS, FT-IR and NMR) showed that the product was efficiently synthesized with a good degree of purity. The Thermo-gravimetric analysis showed that the addition of the new compound promoted a significant increase in thermal stability of mineral naphthenic oils, which confirms its action in inhibition of oxidative process. Conclusion: According to the experimental data a new phosphorylated antioxidant derived from hydrogenated cardol was efficiently synthesized and characterized. This compound presented excellent performance as inhibitor of oxidation of mineral oils, become these oils more resistant to thermal degradation process.
The majority of women during the menopausal period have great hormonal changes that affect both somatic and mental aspects. In modern life, regular exercise has become a necessity and recently is considered as a new alternative method to improve post menopausal symptoms. Aims: The trial intends to evaluate the effect of aerobic exercises on depression and insomnia in post menopausal Egyptian females. Place and Duration of Study: Department of Obstetrics and Gynecology, Bap- Al Sharya Hospital, El- Azhar University and the outpatient clinic of the Faculty of Physical Therapy, Cairo University, between July 2012 and October 2012. Methodology: 20 post menopausal women, their age ranged from 51-63 years and their body mass index was less than 30 kg/m2 attached to this study after meeting the study requirements. All participants were assessed before and after the treatment program through self-rating depression scale (SDS) and Modified Davis Sleep measures scale (MDSS), A program of exercise (walking on a treadmill) started for 30 minutes at 60-70% of target heart rate (THR) for 4 weeks 3 times/week, after that the exercise was increased till 40 minutes for the next 4 weeks. Results: Showed a statistically highly significant decrease (P<0.001) in (SDS) scores and a statistically highly significant increase in Modified Davis Sleep measures scale (MDSS), after the 8 weeks of exercise training. Conclusion: Regular physical activity appears to be an alternative method to decrease depression and insomnia that occur during post menopausal period.
Aims: To design a two degree of freedom compensator for the DC motor, verify the stability of the proposed algorithm as well as the noise sensitivity are carried out. Study Design: The design of the present algorithm is to compare no load and load static parameter dependence. Place and Duration of Study: Department of Electrical Engineering, between October 2012 and January 2013. Methodology: The static parameters of a permanent magnet DC motor speed control with external load torque is simulated. The closed loop system and a two degree of freedom (2DOF) PID controller designed on the basis of the robust response tuning method. However, both no load and load current, speed and torque obtained. Results: The robustness of the proposed algorithm checked through a 2DOF PID controller development. Comparison between classical PID speed response with 2DOF PID speed response carried out. The sensitivity against the noise are approved as well as the torque and current in load and no load has been compared. Conclusion: The simulated results of the proposed algorithm improved performance operation and shows the effectiveness of the compensator new technique compared to the classical one.
The effectiveness of a Cutting Fluid (CF) depends to a large extent on the method of its feeding. Therefore, a new device was developed to feed cutting fluids to the cutting area under lathe machining and specifically for turning process. The device can be used as a two-way or multi CF feeding mechanism depending on the number of nozzles used simultaneously for the application of the CF to the cutting zone. The material used for the construction of the device is low carbon steel, except the nozzles and the nozzle base that were made from brass. The device was tested as a two-way cutting fluid feeding mechanism to apply CF (soluble oil) to the cutting zone during the turning of high carbon steel material with a tungsten carbide cutting tool. The experiments were conducted on centre lathe machine model XL400. The results of the experiment indicated that the two-way application of CF is more effective in terms of its reduction in the tool wear, surface roughness and temperature as compared with the standard one-way application of CF. The average values of surface roughness (Ra), the Tool wear (λ) and Temperature (T) were 8.62µm, 0.12mm and 27.12ºC respectively for two-way application of CF as against 9.67µm, 0.15mm and 30.48ºC for standard one-way application of CF. In other words the surface quality was increased by 11%, the tool life was prolonged approximately by 20% and the temperature was reduced by 11% with the two-way application of CF. Thus, the advantage of a two-way CF feeding mechanism over the standard one-way was ascertained. Dry Turning was also conducted for comparison purpose and naturally, the two-way application of CF showed tremendous advantage over the dry turning for the three parameters (Temperature, Surface Roughness and Tool wear) investigated. The temperature, Surface Roughness and Tool Wear for Two-way application of CF were 27.12ºC, 8.62µm, and 0.12mm as against 50.84ºC, 29.25µm and 1.24mm for dry turning respectively.
The paper describes a simple, small scale and low cost yet comprehensive approach to quantifying the Coefficient of Rolling Resistance/Friction (Crr) also known as the Rolling Resistance Coefficient in automobiles. Crr is usually defined as the amount of force required to overcome the hysteresis of the material during tire rotation, where reduced Crr tires can save 1.5–4.5% of automotive fuel consumption. Automotive Standards from the Society of Automotive Engineers use to quantify Crr namely SAE J2452 and SAE J1269 were briefly introduced. Methods of coast down and speed trap tests were conducted under varying body weighted conditions to find the coefficient value, where a high speed camera monitored the motion of the vehicle. The experiment produced different equations of motion which were then solved analytically by numerical analysis techniques to converge on the rolling friction coefficient. A scaled model was used to run dynamic tests and the Reynolds Number (Re) was used to establish a relationship between model and full scale vehicle velocities. Initial guesses in the least square optimization iterations provided coefficient values where drag forces were normalized by assuming constant drag coefficient (CD of 0.40) and then neglecting its contribution during vehicle motion due to the test model size, resulting in a mean Crr of 0.0116. The study results were compared with 3 studies and also against an automotive Crr model. Schmidt 2010 Dynatest Green Road report shares a high 43% error, while the National Academy of Sciences, 2006 and Gillespie, 1992 yielded errors of 10.5% and 7.2%. The recent mathematical model of Ehsani 2009 yielded an average Crr value error of 2.3% (with individual test averages of 0.80%). Direct scaling and multiplying abilities were attributed for quantifying the normalized value in the study.
Aims/ Objectives: To prepare activated carbon from poultry droppings using H3PO4 as an activating agent and to determine the uptake of BOD from dye effluents at different contact time. Study Design: Experimental study on the effectiveness of the activated carbon at various contact time. Place and Duration of Study: Department of Chemistry Federal University of Technology Minna Niger State Nigeria, between April and November 2010. Methodology: Batch adsorption experiments were carried out for the removal of BOD from dye effluent using poultry droppings as an adsorbent. A two-step process was adopted with H3PO4 as an activating agent and the adsorption was carried out at various contact time. The rate of adsorption was carried out at various contact time. The adsorption kinetic were analysed using pseudo first-order, pseudo second-order, Natarajan and Khalaf first order and Elovich model. Results: The ash content of poultry droppings was low which is an indication of high carbon yield. It is known that as the activation burn off increases the percentage of carbon yield decreases, this is so because more volatiles are released from the char at higher burn off. The lower conductivity values obtained in the study implied that the activated carbon contain less leachable waste that are considered impurity and undesirable. Equilibrium contact time was indicated at short contact time corresponding to 30 minutes for PD/ H3PO4/10 and at long contact time or 120 minutes for PD/H3PO4/5 adsorbent. Furthermore, the pseudo second-order kinetic model was found to be the most appropriate model that best describes the adsorption kinetics. Conclusion: The findings indicated that the poultry droppings could be good raw material for the preparation of activated carbon that could be effectively used for the removal of BOD from dye effluent. The kinetics involved in the adsorption process was intraparticle diffusion control mechanism.
Aims: The study is aimed at analyzing soil samples from various sampling points of the Kazaure glass sand deposit for the levels of lead, cadmium, chromium, nickel, iron, zinc, copper and manganese in order to ascertain the environmental impact of the mining activity. Study Design: To assess the levels of Heavy metals in the glass sand deposits and their effects on the environment by comparing results with reference values obtained in literature. Place and Duration of Study: Department of Pure and Industrial Chemistry, Bayero University, Kano-Nigeria. September 2012- December 2012. Methodology: We determined the soil pH and concentrations of Pb, Cd, Cr, Ni, Fe, Zn, Cu and Mn in fourteen samples of glass sand deposit from Kuma Dangibga village, south of Kazaure town in Jigawa State, Nigeria. Atomic Absorption Spectrophotometric method was used and results obtained were compared with reference values for metals in soils to ascertain the levels of metal pollution. Results: Soil pH values ranged from 7.54 ± 0.23 to 8.36 ± 0.11 indicating neutral to slightly alkaline. The mean levels of metals obtained ranged from 1.25 ± 0.00 mg/kg Cd to 81.16 ± 5.02 mg/kg Zn and in the following order of abundance: Zn> Fe> Pb> Ni> Cr> Cu> Mn>Cd. With the exception of Cd and Cr, the concentrations of the other metals were found to be below the safe limits for metals in soils. Analysis of the result indicates that there no significant differences (p>0.05) between the metal content of the glass sand and those from the adjacent control sites. Conclusion: The results indicate pollution by Cd and Cr which need to be addressed since the lands around the vicinity of the mining site are being utilized for agricultural purposes.
The adsorption of phenol which is one of the most important organic pollutant was studied using carbon from maize tassels. The effect of contact time, adsorbent dosage and temperature on the adsorption capacity was investigated. The maximum phenol adsorption was obtained as 54% at a temperature of 75ºC and at a pH of 6. Freundlich and Langmuir adsorption models were used for mathematical description of the adsorption equilibrium. The experimental data fitted well into the Langmuir isotherm.
To properly characterizing and modelling a hydrocarbon bearing reservoir is not an easy task because the reservoir properties vary spatially due to reservoir heterogeneities which occur at all scales, from pore scale to major reservoir units. The level of reservoir complexities under study determines the quantity and quality of data requirements for 3D reservoir modelling activity. An adequate understanding of the limitations imposed by the data, associated uncertainty, or the underlying geostatistical algorithms or approaches and their input requirements for the 3D reservoir models are absolutely necessary to obtain reasonable production forecasts. Generally, industry look-backs continue to show the difficulty of achieving a production forecast within an uncertainty band (P90 and P10) for both “Greenfield” projects with limited data and “Brownfield” projects with abundant data. Some of the identified key factors affecting production forecasts are: sparse and non-representative data, biased estimates of Original Hydrocarbon In-Place, non-representative inputs distribution in the reservoir models, inadequate static and dynamic models, poor use of seismic data, use of improper analogs, non-unique history matching calibration processes for brownfields and inappropriate use of uncertainty workflows and tools. This paper briefly discusses some of these factors which affect 3D reservoir interpretation and modelling outcomes for the conventional reservoirs, to provide better understanding, propose effective and practical solutions to improve production forecasts based on lessons learned from 3D reservoir modelling studies, authors and industry experiences. In recent years, the industry has developed and used some high-level fit-for-purpose workflows with a closed loop between 3D static and dynamic reservoir modelling under uncertainty with use of appropriate geo-statistical techniques and history look-backs approach which assist capturing the uncertainties in production forecasts and improving the project risks assessment. The evolution of closed loop modelling process will continue as new techniques and technologies are developed and implemented, enhancing our ability to capture the physical realities of the real subsurface world, generate better production forecasts to reduce the risk associated with field developments.