Showing papers by "Sirindhorn International Institute of Technology published in 2017"

Plant microbial fuel cells: A promising biosystems engineering

Abstract: Conversion of waste to energy via a biological process establishes microbial fuel cells (MFC) as a prominent source of sustainable energy. MFC has been investigated for bioelectricity production through organic degradation of wastewater by microbial consortium. The potential of MFC applications in biosensors, desalination and hydrogen gas production has been explored. Many descendants of an MFC have been developed in recent years based upon the configurations, structures and purposes such as sediment MFC, mud MFC, soil MFC, constructed wetland MFC, photosynthetic MFC and biovolt-photogalvanic MFC. A plant microbial fuel cell (PMFC) is a promising modification of MFC that exercises the unique plant-microbe relationship at the rhizosphere region of a plant and converts solar energy into bioelectricity. In-situ bioelectricity and biomass production, rather than the supply of external substrates, make this technology different from traditional MFCs. Thus, designing and understanding PMFCs should be viewed from a biosystems engineering perspective rather than only through MFC methodology. Plant-microbe harmony at the soil interface, driven by rhizodeposition coupled with efficient engineering, ultimately directs towards its real applications. Thus, this paper reviews three main paradigms. Firstly, effects of plants in PMFC via rhizodeposition and photosynthetic activity are explored. Secondly, the role of microbes driven by soil physiochemical and biological characteristics are shown. Thirdly, the engineering aspects involved in designing an efficient configuration are revealed and an attempt is made to interpret the PMFC with biosystems principles. Furthermore, an overview of a PMFC system is done, along with the future perspectives and challenges.

Compressive Behavior of PET FRP–Confined Circular, Square, and Rectangular Concrete Columns

Abstract: This paper presents the results of an experimental study on the compressive behavior of circular and noncircular concrete columns confined by polyethylene terephthalate (PET) fiber-reinforced polymer (FRP). The main objective of this study is to observe the compressive behavior of PET FRP–confined noncircular concrete columns, in which the cross-sectional geometry significantly influences the effectiveness of FRP confinement. For this purpose, 54 specimens were tested under monotonic axial compression. The parameters considered were the cross-sectional shape (i.e., circular, square, and rectangular), the corner radius in case of square and rectangular specimens, and the number of FRP layers. The results of this study showed that, unlike the bilinear stress-strain response of square and rectangular concrete columns confined by other FRP materials, PET FRP–confined square and rectangular concrete columns exhibit a distinct trilinear relationship. Owing to the large rupture strain (LRS) characteristi...

A novel visible light active N-doped ZnO for photocatalytic degradation of dyes

Abstract: A new, simple synthesis route based on combustion reaction was introduced for preparing N-doped ZnO (N-ZnO). The structure and properties of N-ZnO were characterized using various techniques, including XPS, XANES, XRD, FTIR, TGA, SEM, TEM, DRS, BET, and zeta potentiometry. Its photocatalytic activity for the degradation of amaranth (AM) and methylene blue (MB) was evaluated under visible and UV light. It was found that N doping significantly extended the spectral response to the visible region and even up to the near-infrared region. N dopants were photostable and highly soluble within the doped matrix. Using 1 g/L of N-ZnO at pH 7, 89.3% of MB with initial concentration of 10 mg/L could be degraded within 1.5 h under visible light of 16.5 W/m2. Under identical experimental conditions, it took 4 h for N-ZnO to degrade 88.5% of AM. Moreover, the photocatalytically treated dyes are nontoxic against Bacillus cereus, an important soil microorganism.

Microbial fuel cells: Advances in electrode modifications for improvement of system performance

Abstract: There is an increasing trend to conduct the researches related to Microbial Fuel Cells (MFCs) in the recent years. Limited power output has been the major obstacle for the practical application and upscaling of MFCs. Attempts have been made on electrode modifications such as anode treatments, cathode modifications with catalysts and bio cathodes developments to produce varying degrees of improved output current depending upon the types of modifications. Power density and Coulombic efficiency have been considered as the important parameters to analyze the system performances. This paper overviews on the advances made in MFCs’ researches focusing on different types of electrodes modifications along with the involved methodology. Furthermore, the system performances of different modified MFCs are compared in terms of the power density and the Coulombic efficiency.

Optimal design of supply chain network under uncertainty environment using hybrid analytical and simulation modeling approach

Abstract: Models that aim to optimize the design of supply chain networks have gained more interest in the supply chain literature. Mixed-integer linear programming and discrete-event simulation are widely used for such an optimization problem. We present a hybrid approach to support decisions for supply chain network design using a combination of analytical and discrete-event simulation models. The proposed approach is based on iterative procedures until the difference between subsequent solutions satisfies the pre-determined termination criteria. The effectiveness of proposed approach is illustrated by an example, which shows closer to optimal results with much faster solving time than the results obtained from the conventional simulation-based optimization model. The efficacy of this proposed hybrid approach is promising and can be applied as a powerful tool in designing a real supply chain network. It also provides the possibility to model and solve more realistic problems, which incorporate dynamism and uncertainty.

A Hybrid Temporal Reasoning Framework for Fall Monitoring

Abstract: This paper presents a real-time method for detecting a fall at different phases using a wireless tri-axial accelerometer and reports the classification performance when the sensor is placed on different body parts. The proposed hybrid framework combines a rule-based knowledge representation scheme with a time control mechanism and machine-learning-based activity classification. Real-time temporal reasoning is performed using a standard rule-based inference engine. The framework is validated for fall detection performance, false alarm evaluation, and comparison with a highly cited baseline method. Based on a data set with 14 fall types (280 falls) collected from 16 subjects, the highest accuracy values of 86.54%, 87.31%, and 91.15% are obtained for fall detection at pre-impacts, impacts, and post-impacts, respectively. Without post-impact activity information, the side of the waist and chest are the best sensor positions, followed by the head, front of the waist, wrist, ankle, thigh, and upper arm. With post-impact activity information, the best sensor position is the side of the waist, followed by the head, wrist, front of the waist, thigh, chest, ankle, and upper arm. Most false alarms occur during transitions of lying postures. The proposed method is more robust to a variety of fall and activity types and yields better classification performance and false alarm rates compared with the baseline method. The results provide guidelines for sensor placement when developing a fall monitoring system.

Analysis of Optimal Sensor Positions for Activity Classification and Application on a Different Data Collection Scenario.

Abstract: This paper focuses on optimal sensor positioning for monitoring activities of daily living and investigates different combinations of features and models on different sensor positions, i.e., the side of the waist, front of the waist, chest, thigh, head, upper arm, wrist, and ankle. Nineteen features are extracted, and the feature importance is measured by using the Relief-F feature selection algorithm. Eight classification algorithms are evaluated on a dataset collected from young subjects and a dataset collected from elderly subjects, with two different experimental settings. To deal with different sampling rates, signals with a high data rate are down-sampled and a transformation matrix is used for aligning signals to the same coordinate system. The thigh, chest, side of the waist, and front of the waist are the best four sensor positions for the first dataset (young subjects), with average accuracy values greater than 96%. The best model obtained from the first dataset for the side of the waist is validated on the second dataset (elderly subjects). The most appropriate number of features for each sensor position is reported. The results provide a reference for building activity recognition models for different sensor positions, as well as for data acquired from different hardware platforms and subject groups.

Effective removal of cesium by pristine graphene oxide: performance, characterizations and mechanisms

Abstract: Radioactive Cs is a major by-product of nuclear power plants, with high radioactivity and long half-life. It is highly soluble in water and is difficult to remove. In this study, pristine graphene oxide (GO) synthesized via a Hummer's method has been demonstrated as a very efficient Cs sorbent with the maximum adsorption capacity of GO found to be 180, 465, 528 mg Cs/g sorbent at pH of 3, 7, and 12, respectively. The results from Fourier-transform infrared (FTIR) spectroscopy of GO before and after Cs sorption at various pH values reveal the mechanism of Cs sorption by GO. Several functional groups which are carboxyls, phenols, and hole defects containing multi-ether groups, are shown to play an important role in Cs capture. GO's affinity for other major cations found in seawater, namely, Na, K, and Mg was also evaluated, and the effect of these cations in competing with Cs for adsorption on GO was also studied. This reveals GO's exceptional ability in capturing Cs even in the presence of high concentrations of competitive cations and its high potential for use in Cs decontamination, as well as other heavy metal removal applications.

TiO2 as an effective nanocatalyst for photocatalytic degradation of humic acid in water environment

Abstract: Photocatalysis with TiO 2 is used to remove humic acid (HA) in a water environment under UVA and UVC light. The effects of operating parameters, including light intensity, HA concentration, catalyst dose, and contact time are investigated at neutral pH conditions. Results show that HA degradation increases with increasing contact time and light intensity and decreases with increasing HA concentration. Increasing catalyst dose increases the HA degradation up to an optimum value. At pH 7 with an initial HA concentration of 14 mg/L, UVA light of 0.236 mW/cm 2 and catalyst dose of 0.3 g/L, 100% efficiency of the HA degradation can be achieved in 3 h. Under identical experimental conditions with UVC light of 0.284 mW/cm 2 , the efficiency of HA degradation also reaches 100%. Based on total organic carbon (TOC) analysis, the mineralization of HA is found to be lower than the degradation of HA. A negligible amount of TOC on the catalyst surface confirms that HA removal is due to photocatalysis. Moreover, a higher degree of mineralization of HA is found under UVA light although degradation is better under UVC light. This indicates that TiO 2 under UVA light has relatively low selectivity to degrade different compounds, including various intermediates from HA degradation.

Analysis of waste generation variables and people’s attitudes towards waste management system: a case of Bangkok, Thailand

Abstract: Having accurate data of municipal solid waste generation amount is an indispensable factor for effective planning of a waste management system. However, to have accurate estimation, significant waste generation factors have to be identified. In this study, Bangkok is selected as representative of urban cities in developing countries. The city has coped with consequences of a vast amount of waste generation and ineffective waste management system for years. The study aims to examine influential variables affecting generation amount and management problems in Bangkok based on people’s attitudes. Questionnaire surveys and interviews are methods of acquiring primary data. To verify reliability of obtained data, statistical analyses are conducted using the methods of descriptive analysis, hypothesis test, and Pearson correlation. The study shows seven influential waste generation variables. In addition, to learn the exact situation of waste management system, interview results are qualitatively evaluated using stakeholder analysis and TOWS matrix. Stakeholders’ points of concerns and suggested waste management solutions are identified for using in the formulation of waste management plan. The results of this study can facilitate a thorough evaluation as inputs of future research for sustainable waste management system.

Material flows analysis of plastic in Thailand

Abstract: A study of the plastics materials flow analysis (MFA) in Thailand was aim to show the flow of plastic materials through production, consumption and waste management based on the year 2013 and projection to the year 2020. This paper finds the plastic waste generation increasing steadily in line with population growth and increasing consumption. In addition, the simulation under waste management three scenarios includes the following: the business as usual (BAU), increasing recycled rate set on the National Solid Waste Management Master Plan (2016 -2021) and increasing in rate of energy recovery by the Alternative Energy Development Plan 2015-2036 (AEDP 2015). The plastic material flow analysis (MFA) has shown that the implementation of the National Solid Waste Management Master Plan (2016 -2021) or the Alternative Energy Development Plan 2015-2036 (AEDP 2015) can reduce uncollected waste and improper waste disposal. Moreover, there is benefit by adding value from recycled materials and energy recovery.

Toward effective multi-sector partnership: A case of municipal solid waste management service provision in Bangkok, Thailand

Abstract: An increasing amount of municipal solid waste needs an effective waste management system to provide reliable service, but in reality this has failed to respond to the demand. Partnership is considered as a potential solution that can increase waste management service performance. A public-private-community partnership was studied as a potential way to alleviate the impacts of ineffective waste management. Based on the tripartite service concept, the roles and relationships between service providers and service recipients were identified by incorporating analyzed results obtained from questionnaires, interviews, and site visits. Bangkok was selected as a representative urban city in a developing country that has experienced problems caused by ineffective waste management. The results showed that 87.2 percent of respondents thought that everyone should be responsible for and be part of waste management. A public-private-community partnership was a vital factor in a successful waste management system and also had high possibility to be implemented. In the partnership, essential roles were identified for each stakeholder sector including service recipients, intermediaries, and service providers. Based on the tripartite service concept, a modified conceptual model was proposed.

Synthesis and Immunological Studies of the Lipomannan Backbone Glycans Found on the Surface of Mycobacterium tuberculosis.

Abstract: Investigations into novel bacterial drug targets and vaccines are necessary to overcome tuberculosis. Lipomannan (LM), found on the surface of Mycobacterium tuberculosis (Mtb), is actively involved in the pathogenesis and survival of Mtb. Here, we report for the first time a rapid synthesis and biological activities of an LM glycan backbone, α(1–6)mannans. The rapid synthesis is achieved via a regio- and stereoselective ring opening polymerization to generate multiple glycosidic bonds in one simple chemical step, allowing us to finish assembling the defined polysaccharides of 5–20 units within days rather than years. Within the same pot, the polymerization is terminated by a thiol-linker to serve as a conjugation point to carrier proteins and surfaces for immunological experiments. The synthetic glycans are found to have adjuvant activities in vivo. The interactions with DC-SIGN demonstrated the significance of α(1–6)mannan motif present in LM structure. Moreover, surface plasmon resonance (SPR) showed th...

Factors influencing silver recovery and power generation in bio-electrochemical reactors

Abstract: The recovery of silver from Ag+ solution coupled with power generation was investigated in bio-electrochemical system (BES). In this system, chemical energy existing in the organic matter in the anode chamber can be converted biologically to electrical energy which can be used for the reduction of Ag+ ions in the cathode chamber. Results showed that type of substrate influenced the metabolic pathway and affected the cell voltage progression, and columbic efficiency. Silver recovery was not affected by increasing initial pH (2.0 to 7.0) and Ag+ concentration (100 to 1000 mg/L) in the catholyte, whereas power generation was improved. A maximum power density of 8258 mW/m3 and a columbic efficiency of 21.61% could be achieved with 1000 mg/L of Ag+. Ag+ ions were reduced to form metallic deposits as Ag0 crystals on the cathode surface, which were then confirmed by scanning electron microscope (SEM) image and energy dispersive X-ray (EDX) spectrum. The BES reactor had high silver removal (i.e., >96%) after 24 h of operation. When considering the crossover of Ag+ ions through the cation exchange membrane, the removal was in the range of 83.73–92.51%. This crossover was not considerable as compared to the Ag+ initial concentration. At higher initial Ag+ concentration (2000 mg/L), the silver removal decreased to 88.61% and the maximum power density decreased to 5396 mW/m3. This study clearly showed that BES can be employed for silver recovery, wastewater treatment, and also electricity generation.

A linguistic representation based approach to modelling Kansei data and its application to consumer-oriented evaluation of traditional products

Abstract: This paper aims at introducing a new method for Kansei data modelling, which is basically based on the linguistic interpretation of Kansei data and the probabilistic semantics of fuzzy sets. We first interpret a semantic differential scale used in Kansei experiment as a linguistic variable and then propose a new method of how the Kansei value of products can be represented as a probability distribution on the set of Kansei linguistic labels of the linguistic variable. We further extend this Kansei data modelling approach to the cases where the Kansei value is imprecisely given as an interval or a fuzzy number. Furthermore, the proposed approach for modelling Kansei data will be used to develop a target-based model for consumer-oriented evaluation. Finally, a case study for consumer-oriented evaluation of hand-painted Kutani cups, a traditional product in Ishikawa, Japan, is conducted to show the applicability of the proposed Kansei data modelling approach.

Phytoremediation Potential of Plants Growing on the Pb-Contaminated Soil at the Song Tho Pb Mine, Thailand

Abstract: The contamination of lead (Pb) is one of the main environmental problems on a global scale. This study assessed the potential of native metallophytes growing on the Song Tho Pb mine in Kanchanaburi province, Thailand, by a field survey. Plants and the associated soil samples were collected. Total Pb concentrations were analyzed by a flame atomic absorption spectrophotometer after a microwave-assisted acid digestion. While total Pb concentrations of top soils varied from 4881 to 16,720 mg/kg, those in soil around the roots ranged from 421 to 48,883 mg/kg. A total of 12 species belonging to eight families accumulated Pb concentrations in roots (47–32,633 mg/kg) which were higher than those in shoots (non-detected values – 1489 mg/kg). Bidens pilosa, with Pb accumulation in shoots > 1000 mg/kg and translocation factor (TF) > 1, could be useful in phytoextraction as a hyperaccumulator. Thysanolaena latifolia and Mimosa pudica with bioconcentration factor > 1 and TF < 1 could be useful in phytostabiliz...

Waste-to-energy policy in Thailand

Abstract: This paper presents the conversion of waste-to-energy (WtE) in Thailand. The amount of municipal solid waste (MSW) generated in Thailand in 2013 was 26.77 million tons which requires an enormous budget allocation for municipal solid waste management (MSWM). However, the budget is insufficient to provide adequate MSWM services. In order to increase the efficiency, sustainable and environmentally in MSWM, WtE technologies are provided as a solution toward a successful policy. Thailand considers WtE, incineration, refuse derived fuel (RDF), anaerobic digestion, pyrolysis and gasification, and landfill gas recovery to be renewable technologies. These technologies not only reduced the quantity but also improved the quality of waste to meet the required pollution control standards, besides generating a substantial quantity of energy.