Articles in Press
Neural Network-based Hybrid Estimator for Estimating Concentration in Ethylene Polymerization Process: an Applicable Approach (Accepted: 2020-01-08)
Estimation of a monomer concentration of an ethylene polymerization process has been a challenging problem due to its highly nonlinear behavior and interaction among state variables. Applying of an extended Kalman filter (EKF) to provide the estimates of the concentration based on measured bed temperatures has usually been prone to errors. Here, alternatively, neural network-based hybrid estimators have been developed and classified into three structures which integrating of either EKF or Kalman filter (KF) to neural network (NN) to provide the estimates. The NNs are integrated to provide the estimates’ error or concentration’s estimates corresponding to individual structure for reducing the estimation error. Simulation results have shown that the hybrid estimators can provide good estimates under nominal condition and disturbance cases. However, in dealing with noises, the NN-KF hybrid estimator gives superior robustness with smooth and accurate estimated values.
Improvement of Thermal Distribution in the Rubber- Glove Former Conveyor Oven by OpenFOAM (Accepted: 2020-02-17)
The 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 branch hot-air ducts which were installed under the conveyor chain paths. The traditional design of branch hot-air ducts was the cause which the rubber-glove formers were not achieved the hot-air thoroughly even though the grille of branch hot-air ducts was opened along the path of former motion. The computational fluid dynamics (CFD) had been applied to model and analysis 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 branch hot-air ducts were improved to control the hot-air temperature distribution for the most uniformity regarding the CFD results. The comparison between CFD and experiment of the temperature at each point along the oven length was found that the CFD model confirmed an effective improvement and accuracy by an average error less than 8.99%.
Airborne chloride intensity and chloride ion penetration into mortar specimen in Thailand (Accepted: 2020-02-11)
The Southern and Eastern part of Thailand has a long coastal area and located in a hot and humid climate zone. A concrete structure in such environmental conditions tends to have deterioration due to the corrosion of the steel reinforcement by airborne chloride. The concentration of airborne chloride varies by location and exposure condition in each country. Thus, when designing concrete structures in airborne chloride environments, the amount of airborne chloride and the concrete mix proportions should be carefully considered. However, the study about airborne chloride intensity and penetration in Thailand are still limited. Consequently, in this study, airborne chloride in the atmosphere from Phuket Phang-Nga and Chonburi province were collected. The amount of airborne chloride was checked every 1-3 months during the test period. From the results, although the distances from the seashore are almost the same, the airborne chloride intensity varies due to the different exposure directions and environmental conditions. In addition, the mortar specimens with different sources of fly ash were installed in Chonburi province to clarify the airborne chloride penetration behavior. The exposure results showed that airborne chloride penetration rate differs when using the different source of fly ash.
A BIM-Integrated Relational Database Management System for Evaluating Building Life-Cycle Costs (Accepted: 2020-02-12)
Sustainable procurement is considered an important policy for mitigating environmental impacts. Life-cycle cost analysis (LCCA) is a principal tool for evaluating the economic efficiency for the total life cycle budget of a building project, which is an essential requirement in sustainable public procurement systems. Performing building LCCA is an extremely complex and time-consuming process due to repetitive calculations, various regulatory requirements, and a large amount of required data from different sources throughout project life cycle. For conventional data management systems, data are usually stored in paper documents and are input into the systems manually, leading to data loss, inconsistent data, and inaccurate building life-cycle costs (LCC). Building information modeling (BIM) is a modern technology that can overcome the asperities of the conventional building LCCA. However, current BIM tools cannot efficiently accommodate the required data to carry out the building LCCA. A relational database management system (RDBMS) is a tool for organizing, storing, and exchanging data in a logical and systematic fashion. This paper develops a BIM-integrated RDBMS, which provides the required data for the BIM model to perform efficient the building LCCA. This system is achieved through an automatic integration of the BIM authoring programming, the database management system, the spreadsheet system, and the visual programming interface. The proposed system is part of the BIM-database-integrated system for evaluating building life-cycle costs using a multi-parametric model (BIM-BLCC). It represents a new methodology for organizing, storing, and integrating required data for the BIM model to carry out the building LCCA for sustainable procurement systems.
Estimating Concrete Compressive Strength Using MARS, LSSVM and GP (Accepted: 2020-01-09)
The estimation of concrete compressive strength is utmost important for the construction of a building. Organizations have a limited budget for mix design, therefore, proper estimation of concrete data has a significant impact on site operations and the construction of the building. In this paper, the prediction of concrete compressive strength is done by Multivariate Adaptive Regression Spline (MARS), Least Squares Support Vector Machine (LSSVM) and genetic programming (GP). The developed MARS gives equations for concrete. The developed LSSVM is generally based on a statistical learning algorithm. Genetic programming builds equations that are generated for modeling. The efficiency of the MARS, LSSVM and GP are measured by the comparative study.
Use of Natural Rubber Latex (NRL) in improving properties of Reclaimed Asphalt Pavement (RAP) (Accepted: 2020-01-09)
Many issues, especially cost, need to be looked at when a new asphalt materials are considered for road construction. One major factor that impacts the cost is the volatility in oil price and stock availability. Consequently, this factor affects both road construction and maintenance by creating uncertainty and financial challenge for Thai manufacturers. Furthermore, all economies, either national or local, depend on adequate road infrastructure and their sound maintenance for growth and development. One strategy for reducing the overall cost of road construction is through reclamation of existing pavement surfaces that are being repaired or replaced. A process of recycling asphaltic concrete pavement known as Reclaimed Asphalt Pavement (RAP) has been employed in many countries. However, one drawback associated with this practice is the costly investment in the mixing equipment which mechanically rejuvenates the old asphalt pavement by blending it with new asphalt binder. In addition to the high cost of investment, the required quality of the RAP has not been assured due to the lack of enough evidence. The addition of Natural Rubber Latex (NRL) to the process of the recycling asphalt pavement with the aim of reducing production costs and improving the quality of the RAP, offers a promising solution. This paper describes the results of an investigation into the properties of reclaimed asphaltic concrete mix with added NRL. The properties investigated include the Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR). The results show that properties of the NRL modified RAP mix meet the required engineering specifications. The results show that mixing NRL content of 5-15% by weight with RAP and cement content of 3-7% produced a mixture that meet the specification of Thailand Department of Highways in terms of UCS and CBR value for use in layers of pavement. Apart from the positive environmental impact of using recycle material of RAP, the economic and financial benefits to Thailand and rubber farmers make it worth while to use this NRL modified RAP for road construction and maintenance.
Filling-and-Dragging Technique For A Particle-Entrapment Using Triangular Microwells (Accepted: 2020-01-15)
Trapping particle such as a cell, cell spheroid or scaffold bead, in a large trapping spot, such as a microwell, is important in various biological aspects. To achieve high trapping efficacy, the management of two countering effects from hydrodynamic and gravitational force is a key requirement. To increase the possibility of controllable entrapment, this study proposed a new approach using the filling and dragging technique to trap particles. The investigation of the trapping efficacy in three different triangular microwells such as obtuse, equilateral and acute triangle was conducted. The extremely low flow rate was firstly introduced to fill the particles in the microwell, and the flow rate was subsequently increased to drag and rearrange the entrapped particles. High trapping rate of a single particle in an equilateral triangular microwell could reach 80% when trapping polystyrene beads. For biomaterial particle such as cell spheroid, the adhesiveness with the other and the microwell surface is the parameter that needs to be further investigated.
The Examination of the Effects of Land Use Development on the Balance of Mass Transit Ridership (Accepted: 2020-02-11)
The balance of the origin–destination (O-D) ridership distribution is an essential characteristic of a sustainable transit system. However, the existing ridership patterns of transit system in many cities are still off-balance, leading to the inefficient utilization of available capacity. As a result, only one direction is overcrowded whereas the other is not. Many literatures suggest that the transit ridership distribution is generally affected by land use around stations due to the different rates of generated and attracted passengers during each period of time. Therefore, the objective of this study is to verify the effects of land use development according to the Transit Oriented Development (TOD) principle on the balance of the O-D ridership along the transit route, as measured by the discrepancies between the numbers of onboard passengers in stations along a single train line. This study has applied the modified Fluid Analogy Method to reflect the travel behavior of mass transit trip distribution. The results show that, to balance the O-D ridership along a linear and stand-alone transit route, the residential areas should be located near the terminal stations with the sub-residential areas in the interval to shorten the distance of home-based trips. The business areas should be densely situated in the middle of mass transit route, while the retail areas should be located dispersedly all along the route. This study has further applied a proposed model with a case study of MRT Blue Line in Thailand to verify the assumption that the location of the mixed-use project along MRT transit route has impacts on the balance of its ridership. This implication can be a guideline for integrating the mixed-use project development and the land use planning to achieve the sustainable transport in the overall perspective.
Optimization of Biodiesel Production from Waste Cooking Oil in a Continuous Mesoscale Oscillatory Baffled Reactor (Accepted: 2020-02-17)
In this study, a mesoscale oscillatory baffled reactor (OBR) was used to synthesize high methyl esters continuously from waste cooking oil (WCO) in an alcoholic hydroxide solution. Preliminary experiments were conducted to screen for appropriate oscillating frequency and reaction temperature for the transesterification of WCO. Response surface methodology (RSM) based on the Box-Behnken design (BBD) was employed to investigate the influence of residence time, amount of catalyst and methanol-to-oil molar ratio on the FAME content of the product obtained from the OBR. Based on the experimental data, the optimum operating conditions for this process were determined as: residence time of 60 s, catalyst content 3.0%, and methanol-to-oil molar ratio of 9. The product obtained from the optimum reaction condition was analyzed its physical and chemical properties which met the requirements standards.
A multi-level colour thresholding based segmentation approach for improved identification of the defective region in leather surfaces (Accepted: 2020-02-13)
Vision 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.
Mechanical and Thermal Neutron Attenuation Properties of Concrete Reinforced with Low-Dose Gamma Irradiated PETE Fibers and Sodium Borate (Accepted: 2020-02-18)
This 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.