Search results for: mechanism removal

Authors: Diah Tri Widayati, Sunendar, Kresno Suharto, Pudji Asuti, Aris Junaid

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Eight Etawah cross bred does were divided into two groups based on body condition score (BCS). Group I (BSC 2, body weight 25-30 kg; n = 4), and Group II (BSC 3, body weight, 35-40 kg, n=4). All does received intravaginal controlled internal drug release devices (CIDR) for 10 days, and a prostaglandin F2α at 48 h before CIDR removal. Estrus detection was carried out using vasectomized buck. Vaginal epithelium was taken to determine estrus cycle. Blood samples were taken every 3-6 hours, started from moment of CIDR removal until the end of estrus. The results showed vaginal histological indicated estrus occurred at the hours of 25 to 60 and 30 to 70 post CIDR removal in BCS 2 and 3, respectively. Progesterone peak of BCS 2 and BCS 3 were 0.18±0.31 and 0.48±0.31 ng/mL on the hour 0 post CIDR removal. Estradiol -17ß peak of each group was 53.25±35.08 and 89.91±92.84 pg/mL at 48 post CIDR removal. LH surge only occurred on BCS 3 groups, the LH concentrations were 9.9± 9.1; 4.5± 4.0; and 18.2± 9.1 ng/mL at 45, 48 and 51 hours post CIDR removal, respectively. It was concluded that the BCS had effects on vaginal histological changes and LH surge.

Keywords: Estrus synchronization, Vaginal histological changes, Progesterone, Estradiol -17ß , LH

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Authors: Ali W. Alattabi, Khalid S. Hashim, Hassnen M. Jafer, Ali Alzeyadi

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This study was performed to optimise the react time (RT) and study its effects on the removal rates of nitrogen compounds in a sequencing batch reactor (SBR) treating synthetic industrial wastewater. The results showed that increasing the RT from 4 h to 10, 16 and 22 h significantly improved the nitrogen compounds’ removal efficiency, it was increased from 69.5% to 95%, 75.7 to 97% and from 54.2 to 80.1% for NH₃-N, NO₃-N and NO₂-N respectively. The results obtained from this study showed that the RT of 22 h was the optimum for nitrogen compounds removal efficiency.

Keywords: Ammonia-nitrogen, retention time, nitrate, nitrite, sequencing batch reactor, sludge characteristics.

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Authors: Amir Shafeeq, Ayyaz Muhammad, Waqas Sarfraz, Ali Toqeer, Shazib Rashid, M. K. Rafiq

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The current work focuses on rephrasing the harmful effects of mercury that is being released from a number of sources. Most of the sources are from the industrial waste water. Different techniques of mercury removal have been discussed and a brief comparison among these has been made. The experimental work has been conducted for two most widely used methods of mercury removal and comparison in terms of their efficiency has been made.

Keywords: Mercury, Waste Water, Adsorption.

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Authors: M. F. R. Zuthi, H. H. Ngo, W. S. Guo, T. T. Nguyen

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A novel sponge submerged membrane bioreactor (SSMBR) was developed to effectively remove organics and nutrients from wastewater. Sponge is introduced within the SSMBR as a medium for the attached growth of biomass. This paper evaluates the effects of new and acclimatized sponges for dissolved organic carbon (DOC) removal from wastewater at different mixed liquor suspended solids- (MLSS) concentration of the sludge. It was observed in a series of experimental studies that the acclimatized sponge performed better than the new sponge whilst the optimum DOC removal could be achieved at 10g/L of MLSS with the acclimatized sponge. Moreover, the paper analyses the relationships between the MLSSsponge/MLSSsludge and the DOC removal efficiency of SSMBR. The results showed a non-linear relationship between the biomass parameters of the sponge and the sludge, and the DOC removal efficiency of SSMBR. A second-order polynomial function could reasonably represent these relationships.

Keywords: Acclimatization, Dissolved organic carbon, Mathematical model, Sponge submerged membrane bioreactor.

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Authors: Xiaohui Han, Yuhan Wang, Jing Shi

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This paper proposed a stiffness analysis method for a 3-PRS mechanism for welding thick aluminum plate using FSW technology. In the molding process, elastic deformation of lead-screws and links are taken into account. This method is based on the virtual work principle. Through a survey of the commonly used stiffness performance indices, the minimum and maximum eigenvalues of the stiffness matrix are used to evaluate the stiffness of the 3-PRS mechanism. Furthermore, A FEA model has been constructed to verify the method. Finally, we redefined the workspace using the stiffness analysis method.

Keywords: 3-PRS, parallel mechanism, stiffness analysis, workspace.

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Authors: A. Jomartov, K. Jomartova

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One of the main and responsible units of Sulzer projectile loom is picking mechanism. It is specifically designed to accelerate projectile to speed of 25 m / s. Initial speed projectile of Sulzer projectile loom is independent of speed loom and determined the potential energy torsion rod. This paper investigates the dynamics picking mechanism of Sulzer projectile loom during its discharge. A result of calculation model, we obtain the law of motion lever of picking mechanism during its discharge. Construction of dynamic model the picking mechanism of Sulzer projectile loom on software complex SimulationX can make calculations for different thickness of torsion rods taking into account the backlashes in the connections, the dissipative forces and resistance forces

Keywords: Dynamics, loom, picking mechanism, projectile, SimulationX.

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Authors: Pelin Demirçivi, Gülhayat Nasün-Saygılı

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Boron minerals are very useful for various industrial activities, such as glass industry and detergent industry, due to its mechanical and chemical properties. During the production of boron compounds, many of these are introduced into the environment in the form of waste. Boron is also an important micro nutrient for the plants to vegetate but if it exists in high concentrations, it could have toxic effects. The maximum boron level in drinking water for human health is given as 0.3 mg/L in World Health Organization (WHO) standards. The toxic effects of boron should be noted especially for dry regions, thus, in recent years, increasing attention has been paid to remove the boron from waste waters. In this study, boron removal is implemented by ion exchange process using Amberlite IRA-743 resin. Amberlite IRA-743 resin is a boron specific resin and it belongs to the polymerizate sorbent group within the aminopolyol functional group. Batch studies were performed to investigate the effects of various experimental parameters, such as adsorbent dose, initial concentration and pH, on the removal of boron. It is found that, when the adsorbent dose increases removal of boron from the liquid phase increases. However, an increase in the initial concentration decreases the removal of boron. The effective pH values for removal of boron are determined between 8.5 and 9. Equilibrium isotherms were also analyzed by Langmuir and Freundlich isotherm models. The Langmuir isotherm is obeyed better than the Freundlich isotherm.

Keywords: Amberlite resin, boron removal, ion exchange, isotherm models.

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Authors: Azam Marjani, Saeed Shirazian

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This work deals with modeling and simulation of SO2 removal in a ceramic membrane by means of FEM. A mass transfer model was developed to predict the performance of SO2 absorption in a chemical solvent. The model was based on solving conservation equations for gas component in the membrane. Computational fluid dynamics (CFD) of mass and momentum were used to solve the model equations. The simulations aimed to obtain the distribution of gas concentration in the absorption process. The effect of the operating parameters on the efficiency of the ceramic membrane was evaluated. The modeling findings showed that the gas phase velocity has significant effect on the removal of gas whereas the liquid phase does not affect the SO2 removal significantly. It is also indicated that the main mass transfer resistance is placed in the membrane and gas phase because of high tortuosity of the ceramic membrane.

Keywords: Gas separation, finite element, ceramic, sulphur dioxide, simulation.

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Authors: M. M. Rahman, Md. Ashikur Rahman Khan, K. Kadirgama M. M. Noor, Rosli A. Bakar

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This paper deals optimized model to investigate the effects of peak current, pulse on time and pulse off time in EDM performance on material removal rate of titanium alloy utilizing copper tungsten as electrode and positive polarity of the electrode. The experiments are carried out on Ti6Al4V. Experiments were conducted by varying the peak current, pulse on time and pulse off time. A mathematical model is developed to correlate the influences of these variables and material removal rate of workpiece. Design of experiments (DOE) method and response surface methodology (RSM) techniques are implemented. The validity test of the fit and adequacy of the proposed models has been carried out through analysis of variance (ANOVA). The obtained results evidence that as the material removal rate increases as peak current and pulse on time increases. The effect of pulse off time on MRR changes with peak ampere. The optimum machining conditions in favor of material removal rate are verified and compared. The optimum machining conditions in favor of material removal rate are estimated and verified with proposed optimized results. It is observed that the developed model is within the limits of the agreeable error (about 4%) when compared to experimental results. This result leads to desirable material removal rate and economical industrial machining to optimize the input parameters.

Keywords: Ti-6Al-4V, material removal rate, copper tungsten, positive polarity, RSM.

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Authors: Ahmed I. Shehab, Sabah M. Abdel Basir, M. A. Abdel Khalek, M. H. Soliman, G. Elgemeie

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Spent bleaching earth (SBE) recycling and utilization as an adsorbent to eliminate dyes from aqueous solution was studied. Organic solvents and subsequent thermal treatment were carried out to recover and reactivate the SBE. The effect of pH, temperature, dye’s initial concentration, and contact time on the dye removal using recycled spent bleaching earth (RSBE) was investigated. Recycled SBE showed better removal affinity of cationic than anionic dyes. The maximum removal was achieved at pH 2 and 8 for anionic and cationic dyes, respectively. Kinetic data matched with the pseudo second-order model. The adsorption phenomenon governing this process was identified by the Langmuir and Freundlich isotherms for anionic dye while Freundlich model represented the sorption process for cationic dye. The changes of Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were computed and compared through thermodynamic study for both dyes.

Keywords: Spent bleaching earth, Regeneration, Dye removal, Thermodynamics.

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Authors: N. Areerachakul

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The surface water used in this study was collected from the Chao Praya River at the lower part at the Nonthaburi bridge. It was collected and used throughout the experiment. TOC (also known as DOC) in the range between 2.5 to 5.6 mg/l were investigated in this experiment. The use of conventional treatment methods such as FeCl3 and PAC showed that TOC removal was 65% using FeCl3 and 78% using PAC (powder activated carbon). The advanced oxidation process alone showed only 35% removal of TOC. Coupling advanced oxidation with a small amount of PAC (0.05g/L) increased efficiency by upto 55%. The combined BAC with advanced oxidation process and small amount of PAC demonstrated the highest efficiency of up to 95% of TOC removal and lower sludge production compared with other methods.

Keywords: Advanced oxidation process, TOC, PAC

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Authors: A.R. Rahmani, M.T. Samadi, R. Noroozi

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The present work was conducted for the synthesis of nano size zerovalent iron (nZVI) and hexavalent chromium (Cr(VI)) removal as a highly toxic pollutant by using this nanoparticles. Batch experiments were performed to investigate the effects of Cr(VI), nZVI concentration, pH of solution and contact time variation on the removal efficiency of Cr(VI). nZVI was synthesized by reduction of ferric chloride using sodium borohydrid. SEM and XRD examinations applied for determination of particle size and characterization of produced nanoparticles. The results showed that the removal efficiency decreased with Cr(VI) concentration and pH of solution and increased with adsorbent dosage and contact time. The Langmuir and Freundlich isotherm models were used for the adsorption equilibrium data and the Langmuir isotherm model was well fitted. Nanoparticle ZVI presented an outstanding ability to remove Cr(VI) due to high surface area, low particle size and high inherent activity.

Keywords: Adsorption, aqueous solution, Chromium, nZVI, removal.

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Authors: Rainer Schneider, Stephan Lau, Levin Kuhlmann, Simon Vogrin, Maciej Gratkowski, Mark Cook, Jens Haueisen

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Cardiac pulse-related artifacts in the EEG recorded simultaneously with fMRI are complex and highly variable. Their effective removal is an unsolved problem. Our aim is to develop an adaptive removal algorithm based on the matching pursuit (MP) technique and to compare it to established methods using a visual evoked potential (VEP). We recorded the VEP inside the static magnetic field of an MR scanner (with artifacts) as well as in an electrically shielded room (artifact free). The MP-based artifact removal outperformed average artifact subtraction (AAS) and optimal basis set removal (OBS) in terms of restoring the EEG field map topography of the VEP. Subsequently, a dipole model was fitted to the VEP under each condition using a realistic boundary element head model. The source location of the VEP recorded inside the MR scanner was closest to that of the artifact free VEP after cleaning with the MP-based algorithm as well as with AAS. While none of the tested algorithms offered complete removal, MP showed promising results due to its ability to adapt to variations of latency, frequency and amplitude of individual artifact occurrences while still utilizing a common template.

Keywords: matching pursuit, ballistocardiogram, artifactremoval, EEG/fMRI.

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Authors: Chih-Cheng Kao, Hsin- Hua Chu

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This paper mainly proposes an efficient modified particle swarm optimization (MPSO) method, to identify a slidercrank mechanism driven by a field-oriented PM synchronous motor. In system identification, we adopt the MPSO method to find parameters of the slider-crank mechanism. This new algorithm is added with “distance" term in the traditional PSO-s fitness function to avoid converging to a local optimum. It is found that the comparisons of numerical simulations and experimental results prove that the MPSO identification method for the slider-crank mechanism is feasible.

Keywords: Slider-crank mechanism, distance, systemidentification, modified particle swarm optimization.

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Authors: Abdulali Ben Saleh, Mohamed Abudabbus

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The present study based on removal of natural dyes of Roselle petals, then used Roselle petals powder (RPP) as an adsorbent for the removal of methylene blue dye (as a typical cationic or basic dye) from aqueous solutions. The present study shows that used Roselle petals powder exhibit adsorption trend for the dye. The adsorption processes were carried out at various conditions of temperatures ranging from 278 to 338 K ± 2 K , concentrations, processing time and a wide range of pH between 2.5-11. Adsorption isotherm equations such as Freundlich, and Langmuir were applied to calculate the values of respective constants. Adsorption study was found that the currently introduced adsorbent can be used to remove cationic dyes such as methylene blue from aqueous solutions.

Keywords: Adsorption, methylene blue, removal of dyes, Roselle petals powder.

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Authors: Ebadollah Zohrevandi, Rasoul Roustaei, Omid Moradtalab

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In this paper, we first consider the quality of service problems in heterogeneous wireless networks for sending the video data, which their problem of being real-time is pronounced. At last, we present a method for ensuring the end-to-end quality of service at application layer level for adaptable sending of the video data at heterogeneous wireless networks. To do this, mechanism in different layers has been used. We have used the stop mechanism, the adaptation mechanism and the graceful degrade at the application layer, the multi-level congestion feedback mechanism in the network layer and connection cutting off decision mechanism in the link layer. At the end, the presented method and the achieved improvement is simulated and presented in the NS-2 software.

Keywords: Congestion, Handoff, Heterogeneous wireless networks, Adaptation mechanism, Stop mechanism, Graceful degrade.

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Authors: Amin Mojiri, Lou Ziyang

Abstract:

Constructed Wetland (CW) is a reasonable method to treat wastewater. Current study was carried out to co-treat landfill leachate and domestic wastewater using a CW system. Typha domingensis was transplanted to CW, which encloses two substrate layers of adsorbents named ZELIAC and zeolite. Response surface methodology and central composite design were employed to evaluate experimental data. Contact time (h) and leachate-towastewater mixing ratio (%; v/v) were selected as independent factors. Phenols and manganese removal were selected as dependent responses. At optimum contact time (48.7 h) and leachate-towastewater mixing ratio (20.0%), removal efficiencies of phenols and manganese removal efficiencies were 90.5%, and 89.4%, respectively.

Keywords: Constructed wetland, manganese, phenols, Thypha domingensis.

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Authors: Kiyohiro Yamazaki

Abstract:

The purpose of this paper is to examine the hypothesis explaining the mechanism in the case, where the product is deleted or reduced the fundamental function of the product through the product concept changes in the digital camera industry. This paper points out not owning the fundamental technology might cause the change of the product concept. Casio could create new competitive factor so that this paper discusses a possibility of the mechanism of changing the product concept.

Keywords: Casio, digital camera, mechanism, product concept, product development process.

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Authors: Vrajesh Mehta, Anal Chavan

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Treatment of tar-containing wastewater is necessary for the successful operation of biomass gasification plants (BGPs). In the present study, tar-containing wastewater was treated using lime and alum for the removal of in-organics, followed by adsorption on powdered activated carbon (PAC) for the removal of organics. Limealum experiments were performed in a jar apparatus and activated carbon studies were performed in an orbital shaker. At optimum concentrations, both lime and alum individually proved to be capable of removing color, total suspended solids (TSS) and total dissolved solids (TDS), but in both cases, pH adjustment had to be carried out after treatment. The combination of lime and alum at the dose ratio of 0.8:0.8 g/L was found to be optimum for the removal of inorganics. The removal efficiency achieved at optimum concentrations were 78.6, 62.0, 62.5 and 52.8% for color, alkalinity, TSS and TDS, respectively. The major advantages of the lime-alum combination were observed to be as follows: no requirement of pH adjustment before and after treatment and good settleability of sludge. Coagulation-precipitation followed by adsorption on PAC resulted in 92.3% chemical oxygen demand (COD) removal and 100% phenol removal at equilibrium. Ammonia removal efficiency was found to be 11.7% during coagulation-flocculation and 36.2% during adsorption on PAC. Adsorption of organics on PAC in terms of COD and phenol followed Freundlich isotherm with Kf = 0.55 & 18.47 mg/g and n = 1.01 & 1.45, respectively. This technology may prove to be one of the fastest and most techno-economically feasible methods for the treatment of tar-containing wastewater generated from BGPs.

Keywords: Activated carbon, Alum, Biomass gasification, Coagulation-flocculation, Lime, Tar-containing wastewater.

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Authors: Sang Won Han, Won Joo Lee, Sang Jun Lee

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A new multi inner stage (MIS) cyclone was designed to remove the acidic gas and fine particles produced from electronic industry. To characterize gas flow in MIS cyclone, pressure and velocity distribution were calculated by means of CFD program. Also, the flow locus of fine particles and particle removal efficiency were analyzed by Lagrangian method. When outlet pressure condition was –100mmAq, the efficiency was the best in this study.

Keywords: Cyclone, SiO2 particle, Particle removal efficiency, CFD simulation

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Authors: J. K. Choi , D. W. Kim, H. S. Shin, H. J. Yeon, B. K. Kim, Yeon. Fan, D. Chang, S. B. Han, J.M. Hur, B. R. Jung, S. M. Park

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The purpose of this research was develop a biological nutrient removal (BNR) system which has low energy consumption, sludge production, and land usage. These indicate that BNR system could be a alternative of future wastewater treatment in ubiquitous city(U-city). Organics and nitrogen compounds could be removed by this system so that secondary or tertiary stages of wastewater treatment satisfy their standards. This system was composed of oxic and anoxic filter filed with PVDC and POM media. Anoxic/oxic filter system operated under empty bed contact time of 4 hours by increasing recirculation ratio from 0 to 100 %. The system removals of total nitrogen and COD were 76.3% and 93%, respectively. To be observed internal behavior in this system SCOD, NH3-N, and NO3-N were conducted and removal shows range of 25~100%, 59~99%, and 70~100%, respectively.

Keywords: BNR, nitrification, denitrification, organics removal, anoxic, oxic, advanced treatment.

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Authors: A. Mohammed, A. Babatunde

Abstract:

This study investigated the integrated removal of heavy metals, organic matter and nitrogen from landfill leachate using a novel laboratory scale constructed wetland system. The main objectives of this study were: (i) to assess the overall effectiveness of the constructed wetland system for treating landfill leachate; (ii) to examine the interactions and impact of key leachate constituents (heavy metals, organic matter and nitrogen) on the overall removal dynamics and efficiency. The constructed wetland system consisted of four stages operated in tidal flow and anoxic conditions. Results obtained from 215 days of operation have demonstrated extraordinary heavy metals removal up to 100%. Analysis of the physico- chemical data reveal that the controlling factors for metals removal were the anoxic condition and the use of the novel media (dewatered ferric sludge which is a by-product of drinking water treatment process) as the main substrate in the constructed wetland system. Results show that the use of the ferric sludge enhanced heavy metals removal and brought more flexibility to simultaneous nitrification and denitrification which occurs within the microbial flocs. Furthermore, COD and NH₄-N were effectively removed in the system and this coincided with enhanced aeration in the 2nd and 3rd stages of the constructed wetland system. Overall, the results demonstrated that the ferric dewatered sludge constructed wetland system would be an effective solution for integrated removal of pollutants from landfill leachates.

Keywords: Constructed wetlands, ferric dewatered sludge, heavy metal, landfill leachate.

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Authors: W. Ketren, J. Wannapeera, Z. Heishun, A. Ryuichi, K. Toshiteru, M. Kouichi, O. Hideaki

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Degradative solvent extraction is the method developed for biomass upgrading by dewatering and fractionation of biomass under the mild condition. However, the conversion mechanism of the degradative solvent extraction method has not been fully understood so far. The rice straw was treated in 1-methylnaphthalene (1-MN) at a different solvent-treatment temperature varied from 250 to 350 ^oC with the residence time for 60 min. The liquid membrane-Fourier Transform Infrared Spectroscopy (FTIR) technique is applied to study the processing mechanism in-depth without separation of the solvent. It has been found that the strength of the oxygen-hydrogen stretching  (3600-3100 cm^-1) decreased slightly with increasing temperature in the range of 300-350 ^oC. The decrease of the hydroxyl group in the solvent soluble suggested dehydration reaction taking place between 300 and 350 ^oC. FTIR spectra in the carbonyl stretching region (1800-1600 cm^-1) revealed the presence of esters groups, carboxylic acid and ketonic groups in the solvent-soluble of biomass. The carboxylic acid increased in the range of 200 to 250 ^oC and then decreased. The prevailing of aromatic groups showed that the aromatization took place during extraction at above 250 ^oC. From 300 to 350 ^oC, the carbonyl functional groups in the solvent-soluble noticeably decreased. The removal of the carboxylic acid and the decrease of esters into the form of carbon dioxide indicated that the decarboxylation reaction occurred during the extraction process.

Keywords: Biomass upgrading, liquid membrane-Fourier transform infrared spectroscopy, FTIR, degradative solvent extraction, mechanism.

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Authors: Fulya Aydın, Ayşe Kuleyin

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The purpose of this study is to investigate the capacity of natural Turkish zeolite for NH4-N removal from landfill leachate. The effects of modification and initial concentration on the removal of NH4-N from leachate were also investigated. The kinetics of adsorption of NH4-N has been discussed using three kinetic models, i.e., the pseudo-second order model, the Elovich equation, the intraparticle diffuion model. Kinetic parameters and correlation coefficients were determined. Equilibrium isotherms for the adsorption of NH4-N were analyzed by Langmuir, Freundlich and Tempkin isotherm models. Langmuir isotherm model was found to best represent the data for NH4-N.

Keywords: Leachate, Ammonium, zeolite

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Authors: Yannan Wu, An Chen, Yan Zhao

Abstract:

Termination Mechanism is an indispensible part of the emergency management mechanism. Despite of its importance in both theory and practice, it is almost a brand new field for researching. The concept of termination mechanism is proposed firstly in this paper, and the design and implementation which are helpful to guarantee the effect and integrity of emergency management are discussed secondly. Starting with introduction of the problems caused by absent termination and incorrect termination, the essence of termination mechanism is analyzed, a model based on Optimal Stopping Theory is constructed and the termination index is given. The model could be applied to find the best termination time point.. Termination decision should not only be concerned in termination stage, but also in the whole emergency management process, which makes it a dynamic decision making process. Besides, the main subjects and the procedure of termination are illustrated after the termination time point is given. Some future works are discussed lastly.

Keywords: Emergency management, Termination Mechanism, Optimal Termination Model, Decision Making, Optimal StoppingTheory.

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Authors: Thomas Odaker, Dieter Kranzlmueller, Jens Volkert

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We present an approach to triangle mesh simplification designed to be executed on the GPU. We use a quadric error metric to calculate an error value for each vertex of the mesh and order all vertices based on this value. This step is followed by the parallel removal of a number of vertices with the lowest calculated error values. To allow for the parallel removal of multiple vertices we use a set of per-vertex boundaries that prevent mesh foldovers even when simplification operations are performed on neighbouring vertices. We execute multiple iterations of the calculation of the vertex errors, ordering of the error values and removal of vertices until either a desired number of vertices remains in the mesh or a minimum error value is reached. This parallel approach is used to speed up the simplification process while maintaining mesh topology and avoiding foldovers at every step of the simplification.

Keywords: Computer graphics, half edge collapse, mesh simplification, precomputed simplification, topology preserving.

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Authors: A. Benhadji, M. Taleb Ahmed

Abstract:

Among the various methods of treatment, advanced oxidation processes (AOP) are the most promising ones. In this study, Peroxi Electrocoagulation Process (PEP) was investigated for the treatment of detergent wastewater. The process was compared with electrooxidation treatment. The results showed that chemical oxygen demand (COD) was high 7584 mgO₂.L^-1, while the biochemical oxygen demand was low (250 mgO₂.L^-1). This wastewater was hardly biodegradable. Electrochemical process was carried out for the removal of detergent using a glass reactor with a volume of 1 L and fitted with three electrodes. A direct current (DC) supply was used. Samples were taken at various current density (0.0227 A/cm² to 0.0378 A/cm²) and reaction time (1-2-3-4 and 5 hour). Finally, the COD was determined. The results indicated that COD removal efficiency of PEP was observed to increase with current intensity and reached to 77% after 5 h. The highest removal efficiency was observed after 5 h of treatment.

Keywords: Advanced oxidation processes, chemical oxygen demand, COD, detergent, peroxi electrocoagulation process, PEP, wastewater

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Authors: H. A. Gasim, S. R. M. Kutty, M. Hasnain Isa

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Anaerobic treatment has many advantages over other biological method particularly when used to treat complex wastewater such as petroleum refinery wastewater. In this study two Up-flow Anaerobic Sludge Blanket (UASB) reactors were operated in parallel to treat six volumetric organic loads (0.58, 1.21, 0.89, 2.34, 1.47 and 4.14 kg COD/m3·d) to evaluate the chemical oxygen demand (COD) removal efficiency. The reactors were continuously adapting to the changing of operation condition with increase in the removal efficiency or slight decrease until the last load which was more than two times the load, at which the reactor stressed and the removal efficiency decreased to 75% with effluent concentration of 1746 mg COD/L. Other parameters were also monitored such as pH, alkalinity, volatile fatty acid and gas production rate. The UASB reactor was suitable to treat petroleum refinery wastewater and the highest COD removal rate was 83% at 1215 kg/m3·d with COD concentration about 356 mg/L in the effluent.

Keywords: Petroleum refinery wastewater, anaerobic digestion, UASB, organic volumetric loading rate

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Authors: Shashikant R. Kuchekar, Haribhau R. Aher, Priti M. Dhage

Abstract:

The removal vanadium from aqueous solution using natural exchanger was investigated. The effects of pH, contact time and exchanger dose were studied at ambient temperature (25 ⁰C ± 2 ⁰C). The equilibrium process was described by the Langmuir isotherm model with adsorption capacity for vanadium. The natural exchanger i.e. tamarindus seeds powder was treated with formaldehyde and sulpuric acid to increase the adsorptivity of metals. The maximum exchange level was attained as 80.1% at pH 3 with exchanger dose 5 g and contact time 60 min. Method is applied for removal of vanadium from industrial effluents.

Keywords: Industrial effluent, natural ion exchange, Tamarindus indica, vanadium.

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Authors: R. Malekian, J. Abedi-Koupai, S. S. Eslamian

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Nitrogen loss from irrigated cropland, particularly sandy soils, significantly contributes to nitrate (NO3 -) levels in surface and groundwaters. Thus, it is of great interest to use inexpensive natural products that can increase the fertilizer efficiency and decrease nitrate leaching. In this study, the ability of natural Iranian zeolite clinoptilolite (Cp) and surfactant modified zeolite clinoptilolite (SMZ) to remove NH4 + and NO3 -, respectively, from aqueous solutions was determined. The feasibility of using Cp and SMZ as soil amendment to reduce nitrate leaching from soil using lysimeters was also investigated. Zeolite showed 10.23% to 88.42% NH4 + removal efficiency over a wide range of initial NH4 + concentrations. Nitrate removal efficiency by SMZ was 32.26% to 82.26%. Field study results showed that Cp and SMZ significantly (p < 0.05) reduced leachate NO3-N concentration compared to control. There was no significant difference between maximum and mean leachate NO3-N concentration of SMZ lysimeters and those of Cp lysimeters.

Keywords: Ammonium removal, Leaching, Nitrate removal, Surfactant modified zeolite

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