Engineering Journal (Faculty of Engineering, Chulalongkorn University, Bangkok)
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Economic Analysis of The Innovative Eco-Biofilter /Membrane Bioreactor (MBR) System for Community Wastewater Recycling
Get PDFA prototype Eco-biofilter/MBR (Membrane Bioreactor) system has been developed and installed at a community in Chiang Rak Yai Sub-district, Sam Khok District, Pathum Thani Province, Thailand for community wastewater treatment and recycling. This research aims to investigate the performance of Eco-biofilter/MBR system, as well as the economic analysis of willingness to pay for wastewater treatment. A novel porous baked clay biofilter was also developed as an eco-friendly filter media to replace traditional plastic filter in order to reduce plastic pollution to water environment. The effluent quality from the system could meet the international standard for agricultural water reuse. The survey data for economic analysis were collected from the 281 households living in the studied area, analyzed by descriptive statistic and Contingent Valuation Method. The results show the fact that household’s land use has an inverse relationship while the water source use positively correlates to the value of willingness to pay for wastewater treatment at the statistical significance level of 0.05. The economic analysis of the innovative wastewater treatment system reveals the appropriate wastewater treatment fee at 7 THB per cubic meter of wastewater that is a breakeven point. In addition, the Eco-biofilter/MBR also shows many benefits both of direct and indirect benefits such as water reuse potential, opportunity economic value of treated effluent, and reducing medical expenses. The benefit to cost ratio is equal to 1.04
Comparison of Different Synthesis Schemes for Production of Sodium Methoxide from Methanol and Sodium Hydroxide
Get PDFThis research investigates the process simulation of sodium methoxide (NaOCH3) synthesis from methanol (CH3OH) and sodium hydroxide (NaOH) under three synthesis schemes: schemes A, B, and C. Scheme A consisted of one equilibrium reactor and two distillation columns, scheme B one reactive distillation column and one distillation column, and scheme C one reactive distillation column and pervaporation membrane. The simulation parameters included CH3OH/NaOH feed flow ratio (1.2-1.6), number of stages (5-30), bottom flow rate (1400-1600 kg/h), and feed stage location (5, 10, 15, 20, 21, 22, 23, and 24). The simulation parameters were varied to determine the optimal NaOCH3 synthetic conditions under different schemes with 0.01 wt% water content, maximum 45 wt% NaOCH3, and the lowest total energy consumption. The results showed that scheme C had the lowest total energy consumption (34.25 GJ/h) under the optimal synthetic condition of 1.4 for CH3OH/NaOH feed flow ratio, 25 for the number of stages, 1550 kg/h for the bottom flow rate, and the 24th feed stage location, with the NaOCH3 flow rate of 675 kg/h. Scheme C thus holds promising potential as an energy-efficient alternative for synthesis of NaOCH3. The novelty of this research lies in the use of pervaporation membrane in place of distillation column to separate CH3OH from water and to lower energy consumption and capital cost
Hardware Software Co-Design of a Farming Robot
Get PDFFood means life and no one can think about living without food. This is the most fundamental human necessity and food security is one of the major global concern of this century. With the revolution and recent advancements in the field of electronics and communication, there has been a paradigm shift from conventional farming ways to the modern one. This paper talks about the development of hardware software co-design of agricultural farming robot. Our developed farming robot has two parts namely hardware part which further consists of mechanical, electrical, control and tools segments and the software part which allows user to interact with the farming robot via cloud service. Our proposed hardware architecture is compatible with commercial Farmbot product and the developed web-based software can be extended for more features and applications. Furthermore, the developed robot has been tested and it works well
Improvement of Thermal Distribution in the Rubber- Glove Former Conveyor Oven by OpenFOAM
Get PDFThe great number of rubber-glove formers was dried by the hot-air after dipping into the coagulant tank. The wet rubber-glove had been conveyed by chain into the oven with the producing speed and then the hot-air was blown to impinge the rubber-glove formers by the hot-air branch ducts which were installed under the conveyor chain paths. The traditional design of hot-air branch ducts was the cause which the rubber-glove formers were not achieved the hot-air thoroughly even though the grille of hot-air branch ducts was opened along the path of former motion. The computational fluid dynamics (CFD) had been applied to model and analyze the hot-air flow through the grille of the branch hot-air ducts inside the conveyor oven. The open source codes CFD software (OpenFOAM) was used to perform the computational technique to simulate the complex hot-air flow. The hot-air branch ducts were improved to control the hot-air temperature distribution for the most uniformity regarding the CFD results. The temperature comparison between CFD and experiment at each point along the oven length was found that the CFD model confirmed an effective improvement and accuracy under an average error was less than 8.99%
Mechanical and Thermal Neutron Attenuation Properties of Concrete Reinforced with Low-Dose Gamma Irradiated PETE Fibers and Sodium Borate
Get PDFThis research investigated the mechanical and thermal neutron attenuation properties of concrete reinforced with low-dose gamma irradiated polyethylene terephthalate (PETE) fibers. Low dose (20 – 60 kGy) gamma irradiated PETE fibers of 1.3 and 25 denier size were uniformly mixed with concrete at 0.1%, 0.2%, and 0.3% volume fraction. The results showed that the fiber reinforced concrete (FRC) having 25 denier fibers provided higher compressive strength, flexural strength, and toughness than FRC with 1.3 denier fibers. Moreover, addition of PETE fibers in the concrete enhanced thermal neutron attenuation; however, both fibers exhibited no significant difference in thermal neutron attenuation ability. In addition, this study investigated the effects of adding sodium borate, a boron-containing compound, in concrete mixed with PETE at various proportions. It was found that when sodium borate powder was added, the compressive strength of the concrete decreased, whereas the thermal neutron attenuation ability significantly increased with respect to sodium borate content
Antecedents of the Outsourcing Relationship: A Systematic Review
Get PDFRecently, the advancement in business competition is increasing. Outsourcing has become an important strategy in the organizations. Most of the outsourcing objectives are for cost-saving and focusing on the main activities in the organization. To realize the importance of outsourcing, the goal of this research is to explore the key theoretical views that are related to Business Process Outsourcing (BPO) and Information Technology Outsourcing (ITO) relationships which BPO and ITO, which are the same, means that others are responsible for the non-core work but is a different part of the work. Therefore, this research is interesting in terms of seeing the different perspectives of outsourcing. The research articles in the ScienceDirect database from 2000 to 2018 with related domains were collected using related keywords such as BPO, ITO, outsourcing performance, and outsourcing contract duration. After all relative papers were collected, they are categorized into four major topics including (1) Understanding in outsourcing, (2) Related costs in outsourcing, (3) Outsourced long-term relationships, and (4) Internal control systems in outsourced projects. Based on our systematic review, this study summarized the current trends of research in the concerned areas, together with significant findings that can be applied, integrated, or compared with this study
An Analytical Investigation of Thermal Buckling Behavior of Composite Plates Reinforced by Carbon Nano Particles
Get PDFThe research used analytical and numerical methods to test thermal buckling activity for a composite plate structure with a range of Nano fractions. Experimental program with mechanical properties for the Nano composites were carried out and have been validated from previous work. In addition, both mechanical and thermal expansions were tested from previous work experimentally and used in numerical and analytical methods by the Nano composite. The general motion equation for thermal buckling load was derived and then, the results were compared with the numerical results. The analysis showed that the average outcome error was not greater (2.49%). Ultimately, the results showed that the thermal effect results in a buckling of Nano particle strengthening (1%) volume fraction for the adjusted structure of the plate leads to increase thermal buckling strength (63,4%). This achievement modified a high thermal buckling strength with low percentage of Nano volume fraction compared to the previous work in this field
A Multi-Level Colour Thresholding Based Segmentation Approach for Improved Identification of the Defective Region in Leather Surfaces
Get PDFVision systems are recently adopted for defect detection in leather surface to overcome difficulties of labour intensive, time consuming manual inspection process. Suitable image processing techniques needs to be developed for accurate detection of leather defects. Existing research works have focused for gray scale based image processing techniques which requires conversion of colour images using an averaging method and it lacks sensitivity for detecting the leather defects due to the random and texture surface of the leather. This work presents a colour processing approach for improved identification of leather defects using a multi-level thresholding function. In this work, the colour leather images are processed in ‘Lab’ colour domain for improving the human perception of discriminating the leather defects. In the present work, the specific range of values for the colour attributes of different leather defect in colour leather samples are identified using the colour histogram. MATLAB software routine is developed for identifying defects in specific ranges of colour attributes and the results are presented. From the results, it is found that proposed provides a simpler approach for identifying the defective regions based on the colour attributes of the surface with improved human perception. The proposed methodology can be implemented in graphical processing units for efficiently detecting several types of defects using specific thresholds for the automated real-time inspection of leather defects
Compression-Shear Behavior and Water Impermeability of Rubber Seal in Precast Concrete Structures
Get PDFThis paper attempts to apply the precast construction system on concrete swimming pools. Elastomeric bearings are chosen to be used as rubber seals in order to provide both shear resistance between segments and leakage prevention to the structures. The study methods involve 2 main experiments, accordingly. To simulate the conditions of immersed structures, the prototype of precast swimming pool and the joint between segments are designed. The compression-shear tests of such joints are conducted subject to direct shear and confinement to investigate the shear resistance of the rubber seals. The test results show that the final shear stress under confinements of 1 and 2 MPa and rubber hardness levels of 60 and 70 are considerably higher than the required shear stress while the rubbers prevent the slippery. The water impermeability test is conducted on the specimen made with full depth and thickness of the prototype. Three-dimensional finite element models are also created using ANSYS to determine the stresses caused by the post-tensioned BBR bars. Results from numerical models exhibit non-uniformly distributed stresses in the rubber seal. Two other important factors are found to have influence on impermeability performance: the creep effect of rubber and the surface finishing of contacted precasts
Diversity Based on Oversampling Technique for PAM-4 in Optical Wireless Communication Systems
Get PDFThis paper utilizes the concept of oversampling to achieve diversity for optical wireless communication (OWC) systems with four levels pulse amplitude modulation (4-PAM). We propose two contributions to the development of OWC applications. The first one is the implementation of realtime PAM-4 transmitter (Tx) using field-programmable gate array (FPGA). The second one is diversity using oversampling method which can be used to improve the system performance. In this case, each symbol is sampled more than two times, and, averages them all together. The proposed method is fully verified by experimental demonstration for both Tx realtime implementation and the receiver (Rx). The digital PAM format from FPGA is converted to analog format by using a digital-to-analog converter (DAC). With the update rate of 400 Msps, the proposed OWC systems can provide the communication speed over 800 Mbps; and, only a few FPGA resource usages are consumed. The experimental results showed that the bit error rate (BER) free can be achieved applying diversity using oversampling with four taps. Additionally, the communication distances up to 14 m is successfully transmitted