Search results for: Fluoride concentration

Authors: Ashish Pathak, M. G. Dastidar, T. R. Sreekrishnan

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In the present study, the effect of ferrous sulfate concentration and total solids on bioleaching of heavy metals from sewage sludge has been examined using indigenous iron-oxidizing microorganisms. The experiments on effects of ferrous sulfate concentrations on bioleaching were carried out using ferrous sulfate of different concentrations (5-20 g L-1) to optimize the concentration of ferrous sulfate for maximum bioleaching. A rapid change in the pH and ORP took place in first 2 days followed by a slow change till 16th day in all the sludge samples. A 10 g L-1 ferrous sulfate concentration was found to be sufficient in metal bioleaching in the following order: Zn: 69%>Cu: 52%>Cr: 46%>Ni: 45. Further, bioleaching using 10 g/L ferrous sulfate was found to be efficient up to 20 g L-1 sludge solids concentration. The results of the present study strongly indicate that using 10 g L-1 ferrous sulfate indigenous iron-oxidizing microorganisms can bring down pH to a value needed for significant metal solubilization.

Keywords: Bioleaching, heavy metals, sewage sludge, iron oxidizing microorganisms

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Authors: Nik N. Nik Daud, Nur H. Izehar, B. Yusuf, Thamer A. Mohamed, A. Ahsan

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An experiment was conducted using two aeration methods (water-into-air and air-into-water) and followed by filtration processes using manganese greensand material. The properties of groundwater such as pH, dissolved oxygen, turbidity and heavy metal concentration (iron and manganese) will be assessed. The objectives of this study are i) to determine the effective aeration method and ii) to assess the effectiveness of manganese greensand as filter media in removing iron and manganese concentration in groundwater. Results showed that final pH for all samples after treatment are in range from 7.40 and 8.40. Both aeration methods increased the dissolved oxygen content. Final turbidity for groundwater samples are between 3 NTU to 29 NTU. Only three out of eight samples achieved iron concentration of 0.3mg/L and less and all samples reach manganese concentration of 0.1mg/L and less. Air-into-water aeration method gives higher percentage of iron and manganese removal compare to water-into-air method.

Keywords: Aeration, filtration, groundwater, water quality.

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Authors: Yu Zhao, Shinsuke Kato, Jianing Zhao

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Particles exhausted from cars have adverse impacts on human health. The study developed a three-dimensional particle dispersion numerical model including particle coagulation to simulate the particle concentration distribution under idling conditions in a residential underground garage. The simulation results demonstrate that particle disperses much faster in the vertical direction than that in horizontal direction. The enhancement of particle dispersion in the vertical direction due to the increase of cars with engine running is much stronger than that in the car exhaust direction. Particle dispersion from each pair of adjacent cars has little influence on each other in the study. Average particle concentration after 120 seconds exhaust is 1.8-4.5 times higher than the initial total particles at ambient environment. Particle pollution in the residential underground garage is severe.

Keywords: Dispersion, Idling conditions, Particle concentration, Residential underground garage.

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Authors: Sajeena Beevi. B, Jose P. P., G. Madhu

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The aim of this study was to obtain the optimal conditions for biogas production from anaerobic digestion of organic fraction of municipal solid waste (OFMSW) using response surface methodology (RSM). The parameters studied were initial pH, substrate concentration and total organic carbon (TOC). The experimental results showed that the linear model terms of initial pH and substrate concentration and the quadratic model terms of the substrate concentration and TOC had significant individual effect (p < 0.05) on biogas yield. However, there was no interactive effect between these variables (p > 0.05). The highest level of biogas produced was 53.4 L/Kg VS at optimum pH, substrate concentration and total organic carbon of 6.5, 99gTS/L and 20.32 g/L respectively.

Keywords: Anaerobic Digestion, Biogas, Optimization, Response Surface Methodology.

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Authors: Nassereldeen A. Kabashi, Suleyman A. Muyibi. Mohammed E. Saeed., Farhana I. Yahya

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It is important to remove manganese from water because of its effects on human and the environment. Human activities are one of the biggest contributors for excessive manganese concentration in the environment. The proposed method to remove manganese in aqueous solution by using adsorption as in carbon nanotubes (CNT) at different parameters: The parameters are CNT dosage, pH, agitation speed and contact time. Different pHs are pH 6.0, pH 6.5, pH 7.0, pH 7.5 and pH 8.0, CNT dosages are 5mg, 6.25mg, 7.5mg, 8.75mg or 10mg, contact time are 10 min, 32.5 min, 55 min, 87.5 min and 120 min while the agitation speeds are 100rpm, 150rpm, 200rpm, 250rpm and 300rpm. The parameters chosen for experiments are based on experimental design done by using Central Composite Design, Design Expert 6.0 with 4 parameters, 5 levels and 2 replications. Based on the results, condition set at pH 7.0, agitation speed of 300 rpm, 7.5mg and contact time 55 minutes gives the highest removal with 75.5%. From ANOVA analysis in Design Expert 6.0, the residual concentration will be very much affected by pH and CNT dosage. Initial manganese concentration is 1.2mg/L while the lowest residual concentration achieved is 0.294mg/L, which almost satisfy DOE Malaysia Standard B requirement. Therefore, further experiments must be done to remove manganese from model water to the required standard (0.2 mg/L) with the initial concentration set to 0.294 mg/L.

Keywords: Adsorption, CNT, DOE, Manganese, Parameters.

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Authors: Noraini Ahmad, Seripah Awang Kechil, Norma Mohd Basir

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The steady coupled dissipative layers, called Marangoni mixed convection boundary layers, in the presence of a magnetic field and solute concentration that are formed along the surface of two immiscible fluids with uniform suction or injection effects is examined. The similarity boundary layer equations are solved numerically using the Runge-Kutta Fehlberg with shooting technique. The Marangoni, buoyancy and external pressure gradient effects that are generated in mixed convection boundary layer flow are assessed. The velocity, temperature and concentration boundary layers thickness decrease with the increase of the magnetic field strength and the injection to suction. For buoyancy-opposed flow, the Marangoni mixed convection parameter enhances the velocity boundary layer but decreases the temperature and concentration boundary layers. However, for the buoyancy-assisted flow, the Marangoni mixed convection parameter decelerates the velocity but increases the temperature and concentration boundary layers.

Keywords: Magnetic field, mixed Marangoni convection, similarity boundary layers, solute concentration.

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Authors: E. Moroydor Derun, A. S. Kipcak, O. Dere Ozdemir, M. B. Piskin

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Tea is consumed by a big part of the world-s population. It has an enormous importance for the Turkish culture. Nearly it is brewed every morning and evening at the all houses. Also it is consumed with lemon wedge. Habitual drinking of tea infusions may significantly contribute to daily dietary requirements of elements. Different instrumental techniques are used for determination of these elements. But atomic and mass spectroscopic methods are preferred most. In these study chromium, iron and selenium contents after the hot water brewing of black and green tea were determined by Optical Emission Spectroscopy (ICP-OES). Furthermore, effect of lemon addition on chromium, iron and selenium concentration tea infusions is investigated. Results of the investigation showed that concentration of chromium, iron and selenium increased in black tea with lemon addition. On the other hand only selenium is increased with lemon addition in green tea. And iron concentration is not detected in green tea but its concentration is determined as 1.420 ppm after lemon addition.

Keywords: Black tea, green tea, ICP-OES, lemon

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Authors: G.Durai, N.Rajamohan, C.Karthikeyan, M.Rajasimman

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In this study, aerobic digestion of tannery industry wastewater was carried out using mixed culture obtained from common effluent treatment plant treating tannery wastewater. The effect of pH, temperature, inoculum concentration, agitation speed and initial substrate concentration on the reduction of organic matters were found. The optimum conditions for COD reduction was found to be pH - 7 (60%), temperature - 30ÔùªC (61%), inoculum concentration - 2% (61%), agitation speed - 150rpm (65%) and initial substrate concentration - 1560 mg COD/L (74%). Kinetics studies were carried by using Monod model, First order, Diffusional model and Singh model. From the results it was found that the Monod model suits well for the degradation of tannery wastewater using mixed microbial consortium.

Keywords: Tannery, Wastewater, Biological treatment, Aerobic, Mixed culture, Kinetics.

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Authors: Negar Banan, Mohd Talib Latif

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This study investigated the relationship between urban and rural ozone concentrations and quantified the extent to which ambient rural conditions and the concentrations of other pollutants can be used to predict urban ozone concentrations. The study describes the variations of ozone in weekday and weekends as well as the daily maximum recorded at selected monitoring stations. The results showed that Putrajaya station had the highest concentrations of O3 on weekend due the titration of NO during the weekday. Additionally, Jerantut had the lowest average concentration with a reading value high on Wednesdays. The comparisons of average and maximum concentrations of ozone for the three stations showed that the strongest significant correlation is recorded in Jerantut station with the value R2= 0.769. Ozone concentrations originating from a neighbouring urban site form a better predictor to the urban ozone concentrations than widespread rural ozone at some levels of temporal averaging. It is found that in urban and rural of Malaysian peninsular, the concentration of ozone depends on the concentration of NOx and seasonal meteorological factors. The HYSPLIT Model (the northeast monsoon) showed that the wind direction can also influence the concentration of ozone in the atmosphere in the studied areas.

Keywords: Ozone, Hysplit model, Weekend effect, Daily Average and Daily maximum, Malaysia

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Authors: Yusuke Ayato, Takashi Itahashi, Akiko Takatsu, Kenji Kato, Naoki Matsuda

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In situ observation of absorption spectral change of heptil viologen cation radical (HV+.) was performed by slab optical waveguide (SOWG) spectroscopy utilizing indium-tin-oxide (ITO) electrodes. Synchronizing with electrochemical techniques, we observed the adsorption process of HV+.on the ITO electrode. In this study, we carried out the ITO-SOWG observations using KBr aqueous solution containing different concentration of HV to investigate the concentration dependent spectral change. A few specific absorption bands, which indicated HV+.existed as both monomer and dimer on ITO electrode surface with a monolayer or a few layers deposition, were observed in UV-visible region. The change in the peak position of the absorption spectra from adsorption species of HV+. were correlated with the concentration of HV as well as the electrode potential.

Keywords: absorption phenomena, heptil viologen, indium-tin-oxide (ITO) electrode, in situ, slab optical waveguide(SOWG) spectroscopy,

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Authors: Kiurski S. Jelena, Kecić S. Vesna, Aksentijević M. Snežana

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Samples of tap and wastewater were collected in three offset printing facilities in Novi Sad, Serbia. Ten physicochemical parameters were analyzed within all collected samples: pH, conductivity, m - alkalinity, p - alkalinity, acidity, carbonate concentration, hydrogen carbonate concentration, active oxygen content, chloride concentration and total alkali content. All measurements were conducted using the standard analytical and instrumental methods. Comparing the obtained results for tap water and wastewater, a clear quality difference was noticeable, since all physicochemical parameters were significantly higher within wastewater samples. The study also involves the application of simple linear regression analysis on the obtained dataset. By using software package ORIGIN 5 the pH value was mutually correlated with other physicochemical parameters. Based on the obtained values of Pearson coefficient of determination a strong positive correlation between chloride concentration and pH (r = -0.943), as well as between acidity and pH (r = -0.855) was determined. In addition, statistically significant difference was obtained only between acidity and chloride concentration with pH values, since the values of parameter F (247.634 and 182.536) were higher than F_critical (5.59). In this way, results of statistical analysis highlighted the most influential parameter of water contamination in offset printing, in the form of acidity and chloride concentration. The results showed that variable dependence could be represented by the general regression model: y = a₀ + a₁x+ k, which further resulted with matching graphic regressions.

Keywords: Pollution, printing industry, simple linear regression analysis, wastewater.

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Authors: Lili Warly, Evitayani, A. Fariani

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This study was carried out to evaluate concentration of micro minerals (Zn, Fe, Mn, Cu and Se) of forages and their distribution in fiber fraction (neutral detergent fiber/NDF and acid detergent fiber/ADF) in South Sumatra during dry and rainy seasons. Seven species of commonly forages namely Axonopus compressus, Panicum maximum, Pennisetum purpuphoides, Leucaena leucocephala, Centrocema pubescens, Calopogonium mucunoides and Acacia mangium were collected at native pasture during rainy and dry seasons. The results showed that micro minerals concentration of forages and their distribution in fiber fraction varied among species and season. In general, concentration of micro minerals was slightly higher in rainy season compared to dry season either in grass or legumes forages. In grass, concentration of Fe and Mn were above the critical level, while 33.3 %, 100 % and 16.7 % of evaluated grass were deficient in Zn, Cu and Se. Data on legume forages show that 75 % of legumes were deficient in Zn and Mn, 62.5 % deficient in Cu and 50 % deficient in Se. There was no species of legume deficient in Fe. Distribution of micro minerals in NDF and ADF were also significantly affected by species and season and depends on the kinds of element measured. Generally, micro minerals were associated in fiber fractions much higher during dry season compared to rainy season. Iron (Fe) and selenium (Se) in forages were the highest elements associated in NDF and ADF, while the lowest was found in Copper (Cu).

Keywords: Seasons, forages, micro mineral distribution, fiberfraction.

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Authors: Karuppaiya Maruthai, Viruthagiri Thangavelu, Manikandan Kanagasabai

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In the present study, effect of critical medium components (a total of fifteen components) on ethanol production from waste cashew apple juice (CAJ) using yeast Saccharomyces diasticus was studied. A statistical response surface methodology (RSM) based Plackett-Burman Design (PBD) was used for the design of experiments. The design contains a total of 32 experimental trails. The effect of medium components on ethanol was studied at two different levels such as low concentration level (-) and high concentration levels (+). The dependent variables selected in this study were ethanol concentration (g/L) and cellmass concentration (g/L). Data obtained from RSM on ethanol production were subjected to analysis of variance (ANOVA). In general, initial substrate concentration significantly influenced the microbial growth and product formation. Of the medium components evaluated, CAJ concentration, yeast extract, (NH4)2SO4, and malt extract showed significant effect on ethanol fermentation. A second-order polynomial model was used to predict the experimental data and the model fitted the data with a high correlation coefficient (R2 > 0.98). Maximum ethanol (15.3 g/L) and biomass (6.4 g/L) concentrations were obtained at the optimum medium composition and at optimum condition (temperature-30°C; initial pH-6.8) after 72 h fermentation using S.diasticus.

Keywords: cashew apple juice, ethanol, fermentation, yeast, response surface methodology

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Authors: Marius Gheju, Rodica Pode

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The reduction of hexavalent chromium by scrap iron was investigated in continuous system, using long-term column experiments, for aqueous Cr(VI) solutions having low buffering capacities, over the Cr(VI) concentration range of 5 – 40 mg/L. The results showed that the initial Cr(VI) concentration significantly affects the reduction capacity of scrap iron. Maximum reduction capacity of scrap iron was observed at the beginning of the column experiments; the lower the Cr(VI) concentration, the greater the experiment duration with maximum scrap iron reduction capacity. However, due to passivation of active surface, scrap iron reduction capacity continuously decreased in time, especially after Cr(VI) breakthrough. The experimental results showed that highest reduction capacity recorded until Cr(VI) breakthrough was 22.8 mg Cr(VI)/g scrap iron, at CI = 5 mg/L, and decreased with increasing Cr(VI) concentration. In order to assure total reduction of greater Cr(VI) concentrations for a longer period of time, either the mass of scrap iron filling, or the hydraulic retention time should be increased.

Keywords: hexavalent chromium, heavy metals, scrap iron, reduction capacity, wastewater treatment.

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Authors: B. Kubrak J. Wissink H. Herlina

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Two-dimensional Direct Numerical Simulation (DNS) of high Schmidt number mass transfer in a convective flow environment (Rayleigh-B'enard) is carried out and results are compared to experimental data. A fourth-order accurate WENO-scheme has been used for scalar transport in order to aim for a high accuracy in areas of high concentration gradients. It was found that the typical spatial distance between downward plumes of cold high concentration water and the eddy size are in good agreement with experiments using a combined PIV-LIF technique for simultaneous and spatially synoptic measurements of 2D velocity and concentration fields.

Keywords: Air-Water Interface, DNS, Gas Transfer, LIF.

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Authors: Shingo Murakami, Shinichi Enoki

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In structures, stress concentration is a factor of fatigue fracture. Basically, the stress concentration is a phenomenon that should be avoided. However, it is difficult to avoid the stress concentration. Therefore, relaxation of the stress concentration is important. The stress concentration arises from notches and circular holes. There is a relaxation method that a composite patch covers a notch and a circular hole. This relaxation method is used to repair aerial wings, but it is not systematized. Composites are more expensive than single materials. Accordingly, we propose the relaxation method that a single material patch covers a notch and a circular hole, and aim to systematize this relaxation method. We performed FEA (Finite Element Analysis) about an object by using a three-dimensional FEA model. The object was that a patch adheres to a plate with a circular hole. And, a uniaxial tensile load acts on the patched plate with a circular hole. In the three-dimensional FEA model, it is not easy to model the adhesion layer. Basically, the yield stress of the adhesive is smaller than that of adherents. Accordingly, the adhesion layer gets to plastic deformation earlier than the adherents under the yield load of adherents. Therefore, we propose the three-dimensional FEA model which is applied a nonlinear elastic region to the adhesion layer. The nonlinear elastic region was calculated by a bilinear approximation. We compared the analysis results with the tensile test results to confirm whether the analysis model has usefulness. As a result, the analysis results agreed with the tensile test results. And, we confirmed that the analysis model has usefulness. As a result that the three-dimensional FEA model was used to the analysis, it was confirmed that an out-of-plane deformation occurred to the patched plate with a circular hole. The out-of-plane deformation causes stress increase of the patched plate with a circular hole. Therefore, we investigated that the out-of-plane deformation affects relaxation of the stress concentration in the plate with a circular hole on this relaxation method. As a result, it was confirmed that the out-of-plane deformation inhibits relaxation of the stress concentration on the plate with a circular hole.

Keywords: Stress concentration, patch, out-of-plane deformation, Finite Element Analysis.

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Authors: Ghulam Murtaza, Kalsoom Farzana

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The aim of this article is to narrate the utility of novel simulation approach i.e. convolution method to predict blood concentration of drug utilizing dissolution data of salbutamol sulphate microparticulate formulations with different release patterns (1:1, 1:2 and 1:3, drug:polymer). Dissolution apparatus II USP 2007 and 900 ml double distilled water stirrd at 50 rpm was employed for dissolution analysis. From dissolution data, blood drug concentration was determined, and in return predicted blood drug concentration data was used to calculate the pharmacokinetic parameters i.e. Cmax, Tmax, and AUC. Convolution is a good biwaiver technique; however its better utility needs it application in the conditions where biorelevant dissolution media are used.

Keywords: Convolution, Dissolution, Pharmacokinetics, Salbutamol sulphate

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Authors: S. Kowsari, M. Aghaziarati

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Pyrite (FeS2) is a promising candidate for cathode materials in batteries because of it`s high theoretical capacity, low cost and non-toxicity. In this study, nano size iron disulfide thin film was prepared on graphite substrate through a new method as battery cathode. In this way, acetylene black and poly vinylidene fluoride were used as electron conductor and binder, respectively. Fabricated thin films were analyzed by XRD and SEM. These results and electrochemical data confirm improvement of battery discharge capacity in comparison with commercial type of pyrite.

Keywords: Nano pyrite, Thin film, Battery cathode, capacity.

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Authors: Azlin S Azmi, Mus’ab Zainal, Sarina Sulaiman, Azura Amid, Zaki Zainudin

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Microalgae lipid is a promising feedstock for biodiesel production. The objective of this work was to study growth factors affecting marine mutant Synechococcus sp. (PCC 7002) for high lipid production. Four growth factors were investigated; nitrogen-phosporus-potassium (NPK) concentration, light intensity, temperature and NaNO₃ concentration on mutant strain growth and lipid production were studied. Design Expert v8.0 was used to design the experimental and analyze the data. The experimental design selected was Min-Run Res IV which consists of 12 runs and the response surfaces measured were specific growth rate and lipid concentration. The extraction of lipid was conducted by chloroform/methanol solvents system. Based on the study, mutant Synechococcus sp. PCC 7002 gave the highest specific growth rate of 0.0014 h^-1 at 0% NPK, 2500 lux, 40^oC and 0% NaNO₃. On the other hand, the highest lipid concentration was obtained at 0% NPK, 3500 lux, 30^oC and 1% NaNO₃.

Keywords: Cyanobacteria, lipid, mutant, marine Synechococcus sp. PCC 7002, specific growth rate.

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Authors: Brajesh Kumar Jha, Neeru Adlakha, M. N. Mehta

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Calcium [Ca2+] is an important second messenger which plays an important role in signal transduction. There are several parameters that affect its concentration profile like buffer source etc. The effect of stationary immobile buffer on Ca2+ concentration has been incorporated which is a very important parameter needed to be taken into account in order to make the model more realistic. Interdependence of all the important parameters like diffusion coefficient and influx over [Ca2+] profile has been studied. Model is developed in the form of advection diffusion equation together with buffer concentration. A program has been developed using finite volume method for the entire problem and simulated on an AMD-Turion 32-bit machine to compute the numerical results.

Keywords: Ca2+ profile, buffer, Astrocytes, Advection diffusion, FVM

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Authors: Seteno K. O. Ntwampe, Bruno A. Q. Santos

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Different agricultural waste peels were assessed for their suitability to be used as primary substrates for the bioremediation of free cyanide (CN-) by a cyanide-degrading fungus Aspergillus awamori isolated from cyanide containing wastewater. The bioremediated CN- concentration were in the range of 36 to 110 mg CN-/L, with Orange (C. sinensis) > Carrot (D. carota) > Onion (A. cepa) > Apple (M. pumila), being chosen as suitable substrates for large scale CN- degradation processes due to: 1) the high concentration of bioremediated CN-, 2) total reduced sugars released into solution to sustain the biocatalyst, and 3) minimal residual NH4- N concentration after fermentation. The bioremediation rate constants (k) were 0.017h-1 (0h < t < 24h), with improved bioremediation rates (0.02189h-1) observed after 24h. The averaged nitrilase activity was ~10 U/L.

Keywords: Agricultural waste, Bioremediation, Cyanide, Wastewater.

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Authors: Parveen K. Saini, Mayank Kushwaha

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The influence of material property variation on stress concentration factor (SCF) due to the presence of a circular hole in a functionally graded material (FGM) plate is studied in this paper. A numerical method based on complex variable theory of elasticity is used to investigate the problem. To achieve the material property, variation plate is decomposed into a number of rings. In this research work, Young’s modulus is assumed to be varying exponentially and it is found that stress concentration factor can be reduced by increasing Young’s modulus progressively away from the hole.

Keywords: Stress Concentration, Circular Hole, FGM Plate, Bending.

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Authors: Budhi Primasari, Shaliza Ibrahim, M Suffian M Annuar, Lim Xung Ian Remmie

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This study is aimed to investigate feasibility of the aerobic biological process to treat oily wastewater from palm oil food industry. Effect of aeration and sludge concentrations are studied. Raw sludge and raw wastewater was mixed and acclimatized for five days in a stirred tank reactor. The aeration rate (no aeration, low; 1.5L/min and high rate; 2L/min) and sludge concentration (3675, 7350, and 11025mg/L of VSS) were varied. Responses of process were pH, COD, oil and grease, VSS, and PHB content. It was found that the treatment can remove 85.1 to 97.1 % of COD and remove 12.9 to 54.8% of oil & grease. The PHB yield was found to be within 0.15% to 2.4% as PHB/VSS ratio and 0.01% to 0.12% as PHB/COD removed. The higher aeration results a high COD removal and oil & grease removal, while experiment without aeration gives better PHB yield. Higher sludge concentrations (11025mg/L VSS) give higher removal of oil & grease while moderate sludge concentration (7350mg/L VSS) give better result in COD removal. Higher PHB yield is obtained in low sludge concentration (3675mg/L).

Keywords: oily wastewater, COD, PHB, oil and grease

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Authors: A. Heidarinasab, V. Moghaddam Nansa

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This paper deals with rheological behavior of tomato paste from the view point of time independent properties inclusive of processing variables such as sample temperature which influence on rheological properties as well as breaking temperature and concentration which beside the rheological properties, influence on the quality of final product. With this aim 10 tomato paste samples at various concentrations (17-25%) and breaking temperatures (65- 85 C o ) have been produced. The experimental results showed tomato paste behaves as a non-Newtonian semi-fluid which follows power law model that consistency coefficient (K) is supposed function of breaking temperature, concentration and sample temperature with consideration to superimpose function.

Keywords: Breaking temperature, Concentration, Power law, Rheology, Time independent.

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Authors: Hannu Nurmesniemi, Mikko Mäkelä, Risto Pöykiö, Olli Dahl

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Due to the low heavy metal concentrations, the bottom ash from a 32 MW municipal district heating plant was determined to be a potential forest fertilizer as such. However, additional Ca would be needed, because its Ca concentration of 1.9- % (d.w.) was lower than the statutory Finnish minimum limit value of 6.0-% (d.w.) for Ca in forest fertilizer. Due to the elevated As concentration (53.0 mg/kg; d.w.) in the fly ash from the 32 MW municipal district heating plant, and Cr concentration (620 mg/kg; d.w.) in the ash fraction (i.e. mixture of the bottom ash and fly ash) from the 6 MW municipal district heating plant, which exceed the limit values of 30 mg/kg (d.w.) and 300 mg/kg (d.w.) for As and Cr, respectively, these residues are not suitable as forest fertilizers. Although these ash fractions cannot be used as a forest fertilizer as such, they can be used for the landscaping of landfills or in industrial and other areas that are closed to the public. However, an environmental permit is then needed.

Keywords: Ash, fertilizer, peat, forest residue, waste

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Authors: A. Behbahaninia, S. A. Mirbagheri, A. H. Javid

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Heavy metal transfer in soil profiles is a major environmental concern because even slow transport through the soil may eventually lead to deterioration of groundwater quality. The use of sewage sludge and effluents from wastewater treatment plants for irrigation of agricultural lands is on the rise particularly in peri-urban area of developing countries. In this study soil samples under sludge application and wastewater irrigation were studied and soil samples were collected in the soil profiles from the surface to 100 cm in depth. For this purpose, three plots were made in a treatment plant in south of Tehran-Iran. First plot was irrigated just with effluent from wastewater treatment plant, second plot with simulated heavy metals concentration equal 50 years irrigation and in third plot sewage sludge and effluent was used. Trace metals concentration (Cd, Cu) were determined for soil samples. The results indicate movement of metals was observed, but the most concentration of metals was found in topsoil samples. The most of Cadmium concentration was measured in the topsoil of plot 3, 4.5mg/kg and Maximum cadmium movement was observed in 0-20 cm. The most concentration of copper was 27.76mg/kg, and maximum percolation in 0-20 cm. Metals (Cd, Cu) were measured in leached water. Preferential flow and metal complexation with soluble organic apparently allow leaching of heavy metals.

Keywords: Heavy metal, sludge, soil, transport.

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Authors: Nima Es'haghi Gorji, Hossein Movla, Foozieh Sohrabi, Alireza Mottaghizadeh, Mohammad Houshmand, Hassan Babaei, Arash Nikniazi

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For a determined intermediate band position, the effects of electron filling factor and sunlight concentration on the active region thickness and efficiency of the quantum-dot intermediate band solar cell are calculated. For each value of electron filling factor, the maximum point of efficiency obtained and resulted in the optimum thickness of the cell under three different sunlight concentrations. We show the importance of filling factor as a parameter to be more considered. The photon recycling effect eliminated in all calculations.

Keywords: Intermediate band, Sunlight concentration, Efficiency limits, Electron filling factor

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Authors: S. Potivichayanon, T. Sungmon, W. Chaikongmao, S. Kamvanin

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Production of biogas from bakery waste was enhanced by additional bacterial cell. This study was divided into 2 steps. First step, grease waste from bakery industry-s grease trap was initially degraded by Pseudomonas aeruginosa. The concentration of byproduct, especially glycerol, was determined and found that glycerol concentration increased from 12.83% to 48.10%. Secondary step, 3 biodigesters were set up in 3 different substrates: non-degraded waste as substrate in first biodigester, degraded waste as substrate in secondary biodigester, and degraded waste mixed with swine manure in ratio 1:1 as substrate in third biodigester. The highest concentration of biogas was found in third biodigester that was 44.33% of methane and 63.71% of carbon dioxide. The lower concentration at 24.90% of methane and 18.98% of carbon dioxide was exhibited in secondary biodigester whereas the lowest was found in non-degraded waste biodigester. It was demonstrated that the biogas production was greatly increased with the initial grease waste degradation by Pseudomonas aeruginosa.

Keywords: Biogas production, carbon dioxide, methane, Pseudomonas aeruginosa

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Authors: Ali Baladi, Alireza Fallahi Arezoodar

Abstract:

in dissimilar material joints, failure often occurs along the interface between two materials due to stress singularity. Stress distribution and its concentration depend on materials and geometry of the junction. Inhomogenity of stress distribution at the interface of junction of two materials with different elastic modules and stress concentration in this zone are the main factors resulting in rupture of the junction. Effect of joining angle in the interface of aluminum-polycarbonate will be discussed in this paper. Computer simulation and finite element analysis by ABAQUS showed that convex interfacial joint leads to stress reduction at junction corners in compare with straight joint. This finding is confirmed by photoelastic experimental results.

Keywords: Elastic Modules, Stress Concentration, JoiningAngle, Photoelastic.

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Authors: Ghazaleh Monazami Tehrani, Reza Khani Jazani, Rosli Hashim , Ahmad Savari, Belin Tavakoly Sany, Parastoo Parivar, Zhamak Monazami Tehrani

Abstract:

This study investigated the presence of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Musa Bay (around the PETZONE coastal area) from Feb 2010 to Jun 2010. Concentrations of PAHs recorded in the Musa Bay sediments ranged from 537.89 to 26,659.06 ng/g dry weight with a mean value of 3990.74 ng/g. the highest concentration of PAHs was observed at station 4, which is located near the aromatic outlet of Imam Khomeini petrochemical company (station 4: BI-PC Aromatic effluent outlet) in which its concentration level was more than the NOAA sediment quality guideline value (ERL= 4022 ng/g dry weight). Owing to the concentration of PAHs in the study area, its concentration level was still meet the NOAA sediment quality guideline value (ERL: 4022 ng/g dry weight); however, according to the PELq factor, slightly adverse biological effects are associated with the exposure to PAHs levels in the study area (0.1< PELq= 0.24 > 0.5).

Keywords: Musa Bay, PAHs, PETZONE, NOAA, PELq.

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