SEATUC journal of science and engineering
Online ISSN : 2435-2993
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  • 2020 Volume 1 Issue 1 Pages 00-1-
    Published: 2020
    Released: February 18, 2020
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  • 2020 Volume 1 Issue 1 Pages 00-2-
    Published: 2020
    Released: February 18, 2020
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  • 2020 Volume 1 Issue 1 Pages 00-3-
    Published: 2020
    Released: February 18, 2020
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  • 2020 Volume 1 Issue 1 Pages 00-4-
    Published: 2020
    Released: February 18, 2020
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  • 2020 Volume 1 Issue 1 Pages 00-5-00-7
    Published: 2020
    Released: February 18, 2020
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  • Yuichi Abe, Toshiya Hirose
    2020 Volume 1 Issue 1 Pages 1-6
    Published: 2020
    Released: February 18, 2020
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    The proportion of elderly people in traffic accidents is increasing in Japan. It is therefore necessary to make transportation for the elderly safer by automating the electric wheelchair. Technologies that estimate the vehicle position and orientation are required to realize automated driving. One technology is simultaneous localization and mapping. This technology computes the current self-position by comparing a map and data from a sensor. The present study used the normal distributions transform algorithm for self-position estimation. The main aim of the study was to construct a three dimensional map required for self-position estimation on a sidewalk. For the evaluation of this map, self-position estimation was performed using the map and estimated distances were compared with actual distances measured, by a laser range finder. Results show a difference between the actual position and estimated position of approximately 0.05 m in the area of a sidewalk. The self position estimation on the sidewalk using the normal distributions transform was thus accurate. Future work will focus on a next-generation map that contains point data for the upper part of a building.
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  • Bang Kim Tran, Nhan Ngoc Phan, Tinh Quoc Bui, Thien Tich Truong
    2020 Volume 1 Issue 1 Pages 7-12
    Published: 2020
    Released: February 18, 2020
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    An extended twice - interpolation finite element method (XTFEM) based on the consecutive interpolation procedure (CIP) of quadrilateral element in two-dimensional (2D) with continuous nodal stress for stress fields near material interface and geometry boundary such as inclusion and hole is presented. In contrast to the traditional approaches, the approximation shape functions constructed based on the CIP involve both nodal values and averaged nodal gradients as interpolation conditions. The CIP for quadrilateral element is developed recently by Tinh Quoc Bui, et al., 2014. In this work, we exhibit a pioneering extension of CIP – based consecutiveinterpolation quadrilateral element enhanced by enrichment in terms of local partition of unity method to precisely model inclusion and hole contained in 2D structure, taking advantages of the strengths and making use all the desirable features of both techniques, the CIP and the local enriched partition of unity method. The accuracy and performance of the proposed XTFEM are compared with available referred results and ANSYS, the finite element method software.
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  • Tatsuhiko Aizawa, Sho-Ichiro Yoshihara
    2020 Volume 1 Issue 1 Pages 13-20
    Published: 2020
    Released: February 18, 2020
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    Stainless steel specimens were plasma nitrided at 753 K and 623 K to describe the difference in inner nitriding behavior. The high temperature nitriding was characterized by precipitation of chromium nitrides in the surface layer. No microstructure change was seen below the nitriding front end. The low temperature nitriding was characterized by localization in the nitrogen supersaturation. This behavior was analyzed and described by observation and measurement of microstructure below the nitriding front end. This localized nitrogen supersaturation was driven by the grain boundary diffusion of nitrogen atoms. The effect of this localization on the microstructural change at the depth of 435 um from the surface was further discussed to describe the essential mechanism of nitrogen supersaturation. This difference in these two inner nitriding processes was also theoretically discussed by the diffusion model.
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  • Jirada Gosumbonggot, Goro Fujita
    2020 Volume 1 Issue 1 Pages 21-30
    Published: 2020
    Released: February 18, 2020
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    Photovoltaic (PV) technology has wide usages from environmentally friendly reason. Hotspot on PV panel’s surface is considered as a widespread fault consequence from shading, occurs as the heat and damage. Since hotspot is the blind defection and difficult to access the internal circuits especially in cell’s scale, the conventional method by using the infrared camera is used. However, trades in cost and manpower are the main disadvantages. This paper proposes the algorithm to detect the presence of hotspot in PV cell’s scale, derives from the current voltage (I-V) characteristic curves analysis. The proposed algorithm is also integrated with the global maximum power point tracking if the shading condition is detected. The efficiency of the algorithm is tested with the simulation with the graphical, numerical results and status indicators.
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  • Pradita Octoviandiningrum Hadi, Goro Fujita
    2020 Volume 1 Issue 1 Pages 31-37
    Published: 2020
    Released: February 18, 2020
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    Recognized as a key for energy-saving, zero energy building (ZEB) is being enforced as a target by Japan’s government for the average of the newly constructed buildings by 2030. In the ZEB environment, local power generation is expected to be enough for supplying all loads. As the solar energy generation that is generated by PV system relies on the availability of solar radiation, an energy storage system is necessary to complement the system. Both PV and battery system need to be optimized in term of size. This paper proposed the sizing method for PV system equipped with battery system by concerning the energy independence condition which includes the zero energy. The optimization method is based on building’s energy independence represented by the self-sufficiency ratio (SSR) and the self-consumption ratio (SCR). By utilizing these two ratios, the hybrid system size is determined efficiently towards zero energy target.
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  • Champahom Thanapong, Jomnonkwa Sajjakaj, Ratanavaraha Vatanavongs
    2020 Volume 1 Issue 1 Pages 38-45
    Published: 2020
    Released: February 18, 2020
    JOURNALS OPEN ACCESS
    The rear-end crash on highways tends to continuously increase. This is in accordance with many researches pointing out that the collisions are likely to highly occur at the intersection as vehicles have to reduce the velocity to approach into the intersection. Therefore, this research focuses on seeking for the ways decreasing the number of rear-end collisions at the intersection through the guidelines for relevant organizations to improve such as physical features of roads as well as the promotion methods. The accident cases occurring on highways from 2011 to 2015 were the data used to be analyzed by classification and regression tree (CRT). The target variables were rear-end crashes at the intersection/and those outside the intersection. The results from tree model found that the significant variables to be further recommended were: Average traffic volume, road surface type and lighting condition factor. In addition, this research has provided the guidelines for reducing the number of crashes at the intersection. It also guides the study of rear-end crashes at the intersections in the future.
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  • Kim Bang Tran, Quang Sang Nguyen, Tich Thien Truong
    2020 Volume 1 Issue 1 Pages 46-51
    Published: 2020
    Released: February 18, 2020
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    Structures that works for a long time with constant loads will be influenced by the factors that damage them, and creep phenomenon must be considered. Creep phenomenon are one of the serious damaging factors that can be considered to be influenced by the geometry, boundary conditions and material properties of the structures. When studying creeps on a structure working under stable conditions, the material properties must be considered, which is precisely the cause of the deterioration of the structural strength. This problem, which will be solved by a model called viscoelastic model, includes the creep phenomenon that describes the deterioration of the concrete structure subjected to constant load, will be considered as nonlinear problem in the elastic domain of the material. The creep model will be evaluated by the Finite Element Method (FEM) combined Prony's series interpolation through ANSYS software. The creep datas used for Prony's series interpolation are based on international standards. These results obtained by FEM will be compared with available refered results and the results of the analytical method.
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  • Mei-Yee Teoh, Michihiko Shinozaki, Ismail Said
    2020 Volume 1 Issue 1 Pages 52-61
    Published: 2020
    Released: February 18, 2020
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    The growing urban warming and climate change have prompted thermal comfort being studied under the themes of urban quality and sustainability. However, the piecemeal approaches and standards from various disciplines, coupled with their respective set of parameters, drive thermal comfort to be somehow elusive. This study, therefore, reviewed a series of relevant papers and discussed thermal comfort in a more holistic view. This paper focused on the notion of outdoor thermal comfort at the pedestrian-level in order to redefine the practical variables in outdoor comfort studies, mainly from an urban design perspective. Several quantitative and qualitative criteria related to comfort were incorporated into the discussion, including both thermal and non-thermal factors. This paper, firstly, discussed the discrepancy between indoor comfort and outdoor comfort, and next, the variables involved and thermal perception. In the discussion, it suggested a new area of inquiry in which outdoor thermal comfort might be influenced by nontactile stimuli – for example, visual impacts produced by color, light intensity as well as the attractiveness of scenery. Overall, the paper highlighted that the intervention of human senses plays a vital role in presenting the degree of outdoor comfort. It is physical and phenomenological in response to the richness of climate and outdoor environmental characteristics. In conclusion, outdoor thermal comfort study requires a coherent consideration of interface between human and outdoor environments. The integration of urban parameters into thermal physical and psychological sensations can be an alternative to achieve the integrity of this subject.
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  • Thannapat Rattanapatpokin, Chakrit Tachaapikoon, Rattiya Waeonukul, ...
    2020 Volume 1 Issue 1 Pages 62-70
    Published: 2020
    Released: February 18, 2020
    JOURNALS OPEN ACCESS
    This study investigated the yeast species associated with fermented foods in Thailand, focusing on identifying those that could combine the saccharification and fermentation (SSF) steps of malic acid production from cassava pulp. One hundred nighty six isolated yeast were investigated their ability to produce malic acid from glucose and cassava pulp. The result showed that only one isolate, AY33-1, proved to have amylase, xylanase and cellulase activities that crucial for cassava pulp saccharification ,which malic acid was identified as a key product for the growth on cassava pulp. Sequence analysis of the internal transcribed spacer (ITS) and 26S rDNA region indicated that the isolated strain was closely related to the species Meyerozyma caribbica with 99.8% similarity. Malic acid production from strain AY33-1 on YPD supplement with 10% glucose was 11.5 g/L and the productivity was 0.36 g/L/h. Maximum amount of malic acid production from 10% glucose was 22.7 g/L and the productivity was 0.53 g/L/h in the basal medium. The yield of malic acid was increased with 4.45 folds compared with that of Basal medium from YPD. Meyerozyma caribbica AY33-1 was the multiple enzymatic yeasts containing of 17.35U/mg amylase, 5.12 U/mg cellulase, 7.98 U/mg xylanase and also produced pullulanase when grown on cassava pulp. Our results indicate that the isolated AY33-1 is effective on direct malic acid from cassava pulp (1 g/L of malic acid), suggesting the promising yeast for developing high value-added products from cassava pulp
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  • Nattapon Kaisangsri, Orrapun Selamassakul, Chanikan Sonklin, Natta ...
    2020 Volume 1 Issue 1 Pages 71-76
    Published: 2020
    Released: February 18, 2020
    JOURNALS OPEN ACCESS
    This research aimed to evaluate phenolic compounds and antioxidant activities of ethanolic extract from different type of coffee (Arabica and Robusta) and part of coffee (unroasted bean, green cherry and rad cherry). Results showed that total phenolic content of unroasted coffee bean, green coffee cherry, red coffee cherry of Robusta extract were 193.26, 108.37 and 70.45 mg gallic acid equivalent (GAE)/g crude extract, respectively, while Arabica extract were 158.74, 66.76, 15.46 mg GAE/g crude extract, respectively. Thus, the Robusta coffee extract has higher value of total phenolic content than Arabica coffee extract. The highest phenolic acids content including catechin, chlorogenic acid, gallic acid and caffeic acid were found in unroasted Robusta bean. It was 76.90, 992.21, 1.0 and 150.20 mg/g extracts, respectively. Results showed that unroasted Robusta bean extracts was also the highest antioxidant activities. Inhibitory Concentration at 50% (IC50) (DPPH• and ABTS•+) of the extract were 0.131 and 0.338 mg/mL, respectively. Moreover, Robusta coffee extract was applied as active ingredient in glycerin soap. The biological properties of the soap containing coffee extract was investigated. Robusta bean extract and green Robusta cherry extract had higher than soap with red Robusta cherry extract. When the soaps were stored at 45°C for 2 months, ABTS•+ scavenging activity of soap decreased. The results suggested that Robusta coffee bean extracts might be bioactive ingredient for cosmetic products.
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  • Chanikan Sonklin, Natta Laohakunjit, Orrapun Selamassakul, Nattapo ...
    2020 Volume 1 Issue 1 Pages 77-82
    Published: 2020
    Released: February 18, 2020
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    Mungbean hydrolysate (MH) was prepared by bromelain hydrolysis followed by ultrafiltration with different molecular weight cut-off membrane to fractionate peptide which differ in molecular weight (MW: F1(less than)10 kDa, F2=5-10 kDa, F3=1-5 kDa and F4(less than)1 kDa). MH and all fractions were determined their flavor/taste characteristics by sensory analysis, volatile compounds by Gas Chromatography mass spectrometry (GC-MS) and inhibition of linoleic acid peroxidation. Results showed that MH and all fractions possess good flavor/taste and ability to inhibit linoleic acid peroxidation. Especially, fraction 4 ((less than)1 kD) which contain less than 1 kDa of peptide markedly presented high score of meaty flavor (2.0), sweet flavor (3.2), bouillon flavor (2.8), umami taste (2.2) and overall acceptance (2) derived by panelists. Most volatile compounds in MH and its fraction were aldehyde and furan group. The 3-methyl-butanal, 2-pentyl-furan, furfural and benzaldehyde were the major volatile compounds in all samples that peak area of each compounds in F4 were methyl-butanal, 2-pentyl-furan, furfural and benzeneacetaldehyde with peak area of 30.4, 21.1, 23.0 and 24.4 ×107, respectively. F4 showed higher total area of volatile compounds than MH and its fraction which indicated that F4 have the strongest smell. In addition, F4 expressed inhibition of inoleic acid peroxidation by against oxidation during incubation without light at 60 °C for 6 days. Results indicates that mungbean hydrolysate is possible to be multi-functional flavoring agent which had function of food enhancer, food preservative and antioxidant.
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  • Orrapun Selamassakul, Natta Laohakunjit, Nattapon Kaisangsri, Chan ...
    2020 Volume 1 Issue 1 Pages 83-88
    Published: 2020
    Released: February 18, 2020
    JOURNALS OPEN ACCESS
    This work was carried out to optimal hydrolysis condition for producing riceberry protein hydrolysate with high antioxidant. Hydrolysis of the isolated proteins from riceberry was performed using alcalase, flavourzyme and bromelain. Degree of hydrolysis (DH), total phenolic content and antioxidant activities of hydrolysates by alcalase (IRA), flavourzyme (IRF) and bromelain (IRB) were investigated. By comparison, IRF exhibited higher degree of hydrolysates and antioxidant activities than IRA and IRB. Response surface methodology (RSM) revealed that the optimal condition was 10% flavourzyme® and hydrolysis time for 6 h, which resulted in a 56.36 ± 2.05% of 1,1-diphenyl-2- picrylhydrazyl (DPPH•) radical-scavenging activities and a 55.51 ± 0.16% of 2,2’-azino-bis 3-ethylbenzthiazoline-6-sulfonic (ABTS•+) radicalscavenging activities. Moreover, antioxidant activity of IRBs was significantly higher compared to those of the hydrolysates produced from isolated brown rice protein (Khao Dawk Mali 105). Results suggested that high antioxidant activities of IRB could contribute to bioactive peptides and phenolic compounds. Riceberry protein hydrolysates may be further used as healthpromoting ingredients in food industry.
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  • Pornpimon Tongsuk, Sobroney Heng, Sawannee Sutheeworapong, Peerada ...
    2020 Volume 1 Issue 1 Pages 89-96
    Published: 2020
    Released: February 18, 2020
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    A Caldicellulosiluptor sp. strain EP2 was isolated from the sugarcane bagasse pile. It was a thermophilic lignocellulose-degrading anaerobic bacterium. The strain EP2 closely related to Caldicellulosiruptor saccharolyticus DSM 8903 with 98.57% sequence similarity base on 16s rRNA gene analysis. Therefore, the strain EP2 was belonged within the genus Caldicellulosiruptor, given namely Caldicellulosiruptor sp. strain EP2. Interestingly, this strain produced xylanase activity 58.54 Unit/mg, which was 5.9-folds higher than C. saccharolyticus DSM 8903 (9.89 Unit/mg) when cultivated on cellulose powder. The end products obtained from the fermentation of cellulose powder by strain EP2 were mainly acetic acid, ethanol and a small amount of propionic acid and butyric acid, while lactic acid was not detected. The genome of the strain EP2 showed a circular chromosome with size 2,849,880 bp, 2,672 protein-coding genes, 47 tRNA and 9 rRNA genes. Likewise, the genome of strain EP2 indicated that encodes a wide range of glycoside hydrolases (GHs), i.e., hemicellulose-, cellulose-, starchdegrading and chitin-degrading enzymes as 28, 13, 6 and 2 genes, respectively, which higher number of GH genes than C. saccharolyticus DSM8903, especially hemicellulolytic enzymes. Moreover, two cellulosebinding proteins were isolated from the crude enzyme preparation by affinity purification on cellulose. It revealed 16 proteins on SDS-PAGE and five xylanases and four CMCases on zymograms. The result indicated that the strain EP2 produced the xylanolytic-cellulolytic enzymes in a term as a multienzyme complex, which gathers together of enzyme subunits
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  • Keerati Thamapan, Natta Laohakunjit, Orapin Kerdchoechuen, Punchir ...
    2020 Volume 1 Issue 1 Pages 97-103
    Published: 2020
    Released: February 18, 2020
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    The stems of Albizia myriophylla or Cha-em Thai have sweet compounds, which can be extracted by the ultrasound-assisted extraction (UAE) method. This study was to optimize the UAE conditions for maximum Chaem Thai extract relating to the saponin, flavonoid and sugar contents, using box-behnken design (BBD) with response surface methodology (RSM). Three factors and three levels including extraction temperature (X1), sonication time (X2) and extraction ratio (X3) were the independent variables used to optimize the extraction process. The optimized condition for UAE was 64ºC for temperature, 44 min for sonication time and 1:11 g/mL for extraction ratio. At this condition, the experimental values of saponin (1.5920 ± 0.0235 mg/gDW) was closely the predicted values (1.6590 mg/gDW). In addition, UAE extracts showed excellent DPPH radical scavenging activity. The BBD with RSM optimization study showed that the ultrasound-assisted extraction gave higher yield of sweetness compounds from Cha-em Thai than the conventional method.
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  • Van-Thuc Tran, Takizawa Kenta, Akihiko Hanafusa, Shin-ichiroh Yamamoto ...
    2020 Volume 1 Issue 1 Pages 104-109
    Published: 2020
    Released: February 18, 2020
    JOURNALS OPEN ACCESS
    The lower extremity amputation affected seriously to the quality of daily life activities of the amputee. The lower limb prosthesis designing technique currently has been developed to solve many hard problems such as the contact interface between the skin and the socket surface. Understanding the pressure and shear stress of the contact interface between the skin and socket surface during walking is important for socket designing. In this study, the measurement system during subject walking with seven points on the socket which contacted the human skin was proposed. The experiment results showed that the subject would feel much pain during the first peak of the stance phase at medial proximal and anterior distal regions since the total stresses are very high. At anterior proximal region, the pain at first peak mostly is due to the pressure, however, at the second peak stance phase, the pain is more increment due to the shear in the vertical direction.
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