Effect of the sludge recirculation rate on the performances of a two-stage anoxicsubmerged membrane bioreactor (A-SMBR) for the treatment of seafood wastewater

AbstractThe objective of this research is to study the effect of the sludge recirculation rate on the performance of two-stageanoxic-submerged membrane bioreactor (ASMBR) for the treatment of seafood wastewater. The seafood wastewater presents the biodegradable of containing high values of organic matter (COD around 2750 mg.L-1) and organic nitrogen compounds (TKN around 484 mg.L-1). Four values of recirculation rates, from 1/8 to 3 times the inflow rate, were studied during a long operational period. The MBR reactor was operated in subcritical flux conditions and no sludge extraction was done during the whole experimental period. The overall efficiency for the COD and nitrogen compound removal rate was on average 95+3% and 98+2% respectively. The residual COD, TKN and NO3--N concentration in the effluent were 23+4 mg.L-1, 1.2+0.9 mg.L-1 and 29+9 mg.L-1 respectively. In terms of filtration, trans-membrane pressure (TMP) showed a small and constant values in the membrane reactor with a TMP value of around 5-10 mbars. Membrane fouling appeared linked with the soluble organic compound interactions on the membrane surface (irreversible fouling).The quality of treated water met with the standard of wastewater reusefor all classes (A to D) issued by USEPA

ระบบควบคุมแบบไฮบริดโดยอิงแรงและสัญญาณไฟฟ้ากล้ามเนื้อสำหรับหุ่นยนต์ทำกายภาพบำบัด

This paper presents a hybrid control system of rehabilitation robot with force and EMG signals. The proposed control system is implemented on the elbow joint of the 4 DOF universal exoskeleton. Admittance control method is applied to control this rehabilitation robot. However, the transient response of the admittance control cloud lead in a large overshoot when the user moves exoskeleton joint quickly then suddenly stops. Hence, the EMG sensor is used to detect the muscle contraction and then the force input will be set to zero for improving transient response of the hybrid controller. Furthermore, the generalized regression neural network (GRNN) is applied for predicting the static gravity force compensation. The experimental result indicates that the GRNN can predict the static gravity force with accuracy of 97.32%. Moreover, 83.13% of the transient response is improved by the utilization of the EMG signal in the hybrid controller

Influences of Aging and Inflation Pressure on Stiffness and Absorbed Energy of a Passenger Car Radial Tire

The objective of this study is to investigate the influences of aging and inflation pressure on the stiffness and absorbed energy of radial tires. By quasi-static compression test, new and 50,000-km used tires were determined for acting force and corresponding displacement. Between the 172.4 kPa and 241.3 kPa inflation pressure range for the new tire, the load was linearly increased with displacement. The absorbed energy was non-linear increasing with the displacement. The trend of the accumulative absorbed energy was increased when inflated the tire pressure. For both new and used tires, the stiffness and the absorbed energy were linearly increasing with the inflation pressure. The used tire was harder than the new tire observed by the higher tire stiffness and can be absorbed greater energy. At the rated inflation pressure of 220.6 kPa, after 50,000 km usage, the tire was intensified by 2.62% in terms of stiffness and by 2.22% in terms of energy absorbed. On average, over the inflation pressure in the range of 172.4 kPa to 241.3 kPa, the stiffness and absorbed energy were by 3.22 % and 2.98 % increase for the aging tire compared to the base new tire.Keywords: car; energy; passenger; stiffness; suspension; tir

Efficiency Improvement of Aluminum Recycling Process

AbstractAluminum has been used as a raw material in the automotive, aerospace, cookware and construction industries, including daily appliances. The manufacturing of aluminum ingot from aluminum scraps involves the recycling process where the aluminum scraps are melted and recast together with the modification of chemical composition. Since the recycling process has to account some operations to prepare and manage the scraps, the process is generally ineffective in terms of time and activities related. This in turn leads to the increased waiting time and cycle time of the process. This research therefore aims at increasing the efficiency of aluminum recycling process with emphasizing on the cycle time reduction. The ECRS technique and 5W1H activity analysis were employed to eliminate wastes in each operation of the process. The casting techniques were used to reduce scarp melting time which shared the largest portion of the whole production time. After the process improvement, wastes can be eliminated, thus increasing the efficiencies of man and machines from 34.12% and 59.46% to 50.68% and 61.95%, respectively. The average production cycle time can be reduced from 25.91 hours to 20.13 hours, thus saving the manufacturing cost by 421,327.65 baht accordingly

Removal of Lead from Synthetic Wastewater using Aquatic Plants

AbstractAbilities of aquatic plant species, Echinodosus cordifolius (L.) Griseb., Bacopa caroliniana (Walt.) Rob., and Hydrocotyle umbellata L., for phytoremediation of lead (Pb) from synthetic wastewater were conducted in hydroponic system at 20-80 mg/L of Pb (II) and 7-28 days of exposure periods. Additional experimental set up for aquatic plant species under 60 and 80 mg/L of Pb (II) were added with 5 mM EDTA in order to enhance Pb accumulation in the plants. Results revealed that the capacity of Pb (II) accumulation at 80 mg/L of Pb (II), 28 days in roots of all aquatic plants was higher than that of shoots. E. cordifolius (L.) Griseb. had the highest capacity of Pb (II) accumulation about 12,566 (roots) and 8,686 (shoots) mg/kg dry wt, respectively giving 95% of Pb (II) removal, followed by H. umbellata L. and B. caroliniana (Walt.) Rob., respectively. Regarding EDTA addition, lead accumulation (80 mg/L of Pb (II), 7 days) was increased in the roots of H. umbellata L. about 19,883 mg/kg dry wt and it was increased in the shoots of E. cordifolius (L.) Griseb. about 14,516 mg/kg dry wt (80 mg/L of Pb (II), 21 days), respectively. The highest relative growth (13.85) and percentage of biomass productivity (98%) were in H. umbellata L. (60 mg/L of Pb (II), 7 days), whereas the highest bioconcentration factor (9,341.68) was in E. cordifolius (L.) Griseb.(80 mg/L of Pb (II), 21 days). According to the results, E. cordifolius (L.) Griseb. was recommended to remove the lead from synthetic wastewater with EDTA addition. Further studies in contaminated wastewater under various characteristics and flows should be investigated

Assessment of Wind Energy Potential in Thailand Based on Using the Multiple-Weibull Distribution

AbstractWind energy potential analysis is a design key to maximize wind turbine efficiency and annual energy output. Typically, the annual wind speed frequency is represented by a Single-Weibull distribution curve in spite of strong and calm wind patterns could occur through a year in many regions in the world, Thailand for instance.  For this reason, wind energy potential should be analyzed by Multiple-Weibull distribution curves which are the representative of the meteorological seasons due to the monsoon’s effect.  Therefore the objective of this study is to compare the accuracy of the Single-Weibull distribution and the Multiple-Weibull distribution in assessment of wind energy potential.  The comparison was made between these two statistical distribution functions and the actual wind speed distribution (measured wind speed frequency) in order to determine the level of credibility of these two distribution functions.  The wind speed data employed in this study was measured at Lamtakhong dam site in Nakhon Ratchasima province, Thailand.  As the results, the error between the Single-Weibull distribution was 16.46% where the error between the Multiple-Weibull distribution was 14.82%, it was revealed that the smaller error, the higher reliability.  Two of the most widely used wind turbines (Enercon E-30 and Windspot) were selected to verify the Multiple-Weibull concept.  Approximately 40% increase in annual energy yield by using this method.  So, the results confirmed that the Multiple-Weibull distribution is valid for the assessment of the annual energy production of wind turbines.  Therefore, this will be a practical method for achieving the optimal design of stall-regulated wind turbine in the further work

Effect of Closing the Blade Tip on Downwind Thai Sail Windmill

Thai sail windmill has been a traditional wind turbine of Thailand, which is a type of horizontal axis wind turbine and now used for pumping the seawater into the salt farms widely in the Samut- Songkhram province for the sea salt production. Currently, the efficiency of the conventional Thai sail windmill is typically quite low that is only approximately 10 percent. Actually, the efficiency of wind turbines depends on many parameters such as blade shape, pitch angle, solidity, wind speed, tip loss, etc. However, this study focused on the tip loss reduction by using technique of closing the blade tip in order to be a guideline for enhancing efficiency. The objective of this study was to investigate the effect of employing technique of closing the blade tip on the efficiency of Thai sail windmill in the fashion of downwind rotor. For experiments, the small scale of 4-blade and 6-blade rotor in the pattern of downwind Thai sail windmill was built and used as a prototype to experiment by using the tow testing method. As a result, the use of technique of closing the blade tip could help the 4-blade rotor increase maximum efficiency from 17 percent into 22 percent at the tip speed ratio of 2.2 and help the 6-blade rotor increase maximum efficiency from 25 percent into 35 percent at the tip speed ratio of 2.0.KeywordsThai sail windmill; Wind turbine efficiency; Downwind rotor; Closing the blade ti

Investigation of the Optimal Machining Parameters on Wire Electrical Discharge Machine by Taguchi Technique

This paper focused on the effect of process parameters on material removal rate (MRR), feed rate (FR) and surface roughness (SR) of machining titanium by wire electrical discharge machine (WEDM). The Taguchi method had been used based on L9 orthogonal array to find out the optimal process parameters. This work also investigated the influences of machining parameters including peak current, wire-speed, wire tension and voltage. The experiment was analyzed by Minitab 16 which observed that the peak current was the most influential factor for MRR, FR and SR. However, the wire speed was significant to the feed rate. The optimum parameters of obtained MRR, FR and SR were 20.57 mm3/min, 22.43 mm/min and 1.74 mm, respectively. Thereafter, the scanning electron microscope (SEM) was used to identify the microstructure of the workpiece. It could be seen that craters had more by the high discharge of thermal energy that caused the formation of larger cracks and craters, leading to an increase in surface roughness.KeywordsMaterial removal rate (MRR), Feed rate (FR), Surface roughness (SR), Taguchi method, Wire electrical discharge machining (WEDM