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Journal of Engineering and Technological Sciences

JETS
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Published by Institut Teknologi Bandung

ISSN : 23375779 EISSN : 23385502 DOI : -

Core Subject : Engineering,

Engineering

Journal of Engineering and Technological Sciences welcomes full research articles in the area of Engineering Sciences from the following subject areas: Aerospace Engineering, Biotechnology, Chemical Engineering, Civil Engineering, Electrical Engineering, Engineering Physics, Environmental Engineering, Industrial Engineering, Information Engineering, Mechanical Engineering, Material Science and Engineering, Manufacturing Processes, Microelectronics, Mining Engineering, Petroleum Engineering, and other application of physical, biological, chemical and mathematical sciences in engineering. Authors are invited to submit articles that have not been published previously and are not under consideration elsewhere. Starting from Vol. 35, No. 1, 2003, full articles published are available online at http://journal.itb.ac.id, and indexed by Scopus, Index Copernicus, Google Scholar, DOAJ, GetCITED, NewJour, Open J-Gate, The Elektronische Zeitschriftenbibliothek EZB by University Library of Regensburg, EBSCO Open Science Directory, Ei Compendex, Chemical Abstract Service (CAS) and Zurich Open Repository and Archive Journal Database. Publication History Formerly known as: ITB Journal of Engineering Science (2007 â€“ 2012) Proceedings ITB on Engineering Science (2003 - 2007) Proceedings ITB (1961 - 2002)

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Articles 1,267 Documents

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The Effect of Nanocrystalline Cellulose (NCC) Filler on Polylactic Acid (PLA) Nanocomposite Properties Simangunsong, Daniel I.; Hutapea, Try H. A.; Lee, Hyung Woo; Ahn, Jung Oh; Sitompul, Johnner
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

This paper discusses the effect of nanocrystalline cellulose (NCC) when used as filler on polylactic acid (PLA)-based nanocomposites and on its mechanical properties and permeability. NCC was produced from commercial cellulose and another cellulose source, i.e. oil palm empty fruit bunch, by hydrolysis of microcrystalline cellulose with sulphuric acid and by oxidation with ammonium persulfate. The nanocomposites were made by adding nanocrystalline cellulose with varying compositions into PLA. A solvent casting method was used to produce a nanocomposite film with 5% v/v triacetin as a coupling agent. Both methods produced crystalline celluloses within the micro and nano range with mean particle size at 99.5 nm and 157.9 nm for the sulphuric acid hydrolysis and the ammonium persulfate oxidation method, respectively. The utilization of NCC as PLA composite filler increased the percentage of elongation at break with a highest percentage 19.02% for addition of 1% NCC filler. However, higher compositions of cellulosic filler resulted in a decreasing trend of tensile strength and elongation at break. Higher content of NCC filler in the PLA matrix increased the nanocompositeâs water vapor permeability.

Solar Radiation Forecast Using Cloud Velocity for Photovoltaic Systems Leng Sing, Calvin Kong; Lit Ken, Tan; Kok Yee, Lai; Oktavia Kamadinata, Jane; bin Che Sidik, Nor Azwadi; Asako, Yutaka; Kee Quen, Lee
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Today, solar energy is used in a many different ways. One of the most popular technological developments for this purpose is photovoltaic conversion to electricity. However, power fluctuations due to the variability of solar energy are one of the challenges faced by the implementation of photovoltaic systems. To overcome this problem, forecasting solar radiation data several minutes in advance is needed. In this research, a methodology to forecast solar radiation using cloud velocity and cloud moving angle is proposed. Generally, a red-to-blue ratio (RBR) color model and correlation analysis are used for obtaining the cloud velocity and moving angle. Artificial neural network (ANN) forecast models with different input combinations are established. This methodology requires lower computational time since it only uses part of the pixels in the sky image. Based on R-squared analysis, it can be concluded that the ANN model with inputs of cloud velocity and moving angle and average solar radiation showed the highest accuracy among other combinations of inputs. The R-squared value was 0.59 with only a relatively small sample size of 42. The proposed model showed a highest improvement of 75.79% when compared to the ANN model based on historical solar radiation data only.

Settlement Evaluation of a Concrete Face Rock-Fill Dam (CFRD) Using a Back-Analysis Method Based on Measurement Results (A Case Study of Siah-Bisheh Dam) Abedian, Mohammad Ali; Farrokhi, Farhang; Rasouli, Reza
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

The behavior of the Siah-Bisheh concrete face rock-fill dam in Mazandaran, Iran was investigated. Numerical analyses were performed before construction to evaluate the stability and predict the deformation of the dam. The material properties were chosen based on the results of geotechnical investigations. The amounts for deformation and settlement of the concrete surface were also calculated with the numerical model. The information from a number of geotechnical instruments was collected after construction and analyzed to measure settlement at different sections of the dam. The locations of the different deformations and their values are presented with various contours. The data were analyzed and used to revise the original numerical model of the dam. Following that, the long-term stability of the dam was evaluated, using parameters that were modified based on the measurement data. A comparison of the results from the numerical analysis and the values obtained from the dam settlement measurement showed that the initial results from the numerical model were much higher than the real values. It also showed that the number of construction layers used in the modeling of the dam had a significant effect on the obtained maximum amount of deformation.

An Adaptive Skin Detection Approach of Face Images with Unequal Luminance, Color Excursion, and Background Interference Wei, Li; Luo, Jian; Li, YanMei
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.4.4

Face detection and recognition are affected greatly by unequal luminance, color excursion and background interference. For improving skin detection rates of color face images in the presence of unequal luminance, color excursion and background interference, this paper proposes an approach for automatic skin detection. This approach globally corrects the color excursion using the X, Y, Z color components. Then it establishes a self-adaptive nonlinear amendment function using the aâ, bâand Lâ components, and locally corrects the R, G, B color components of row-column transformed sub-block images to balance the global luminance and color. Finally, it constructs an Lâaâbâthree-dimensional semi-supervised dual-probability skin model, based on which automatic skin detection can be realized. The experimental results demonstrated that this approach has great adaptability, a high detection rate and speed.

Development of Hydro-Meteorological Hazard Early Warning System in Indonesia Susandi, Armi; Tamamadin, Mamad; Pratama, Alvin; Faisal, Irvan; Wijaya, Aristyo R.; Pratama, Angga F.; Pandini, Olgha P.; Widiawan, Destika Agustina
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

This paper discusses the result of the development of a hydro-meteorological hazard early warning system (H-MHEWS) that combines weather prediction from Weather Research and Forecasting (WRF) and the hydrometeorological hazard index from the National Disaster Management Authority (BNPB), Indonesia. In its current development phase, the hazards that H-MHEWS predicts are floods, landslides, and extreme weather events. Potential hazard indices are obtained by using an overlay approach and resampling so that the data have a 100-m spatial resolution. All indices are classified into 4 status categories: âNo alertâ, âAdvisoryâ, âWatchâ, and âWarningâ. Flood potential is produced by overlaying rainfall prediction at 3-hour intervals with the flood index. Landslide potential is produced by overlaying rainfall prediction with the landslide index. Extreme weather potential is divided into 3 categories, i.e. heavy rain, strong winds, and extreme ocean waves. The whole prediction is dynamic, following weather predictions at 3-hour intervals. The hazard prediction results will trigger a âWarningâ alert in case of emergency status. This alert will be set up in a notification system to make it easier for the user to identify the most dangerous hydrometeorological hazard events.

Multi-AGV Path Planning for Indoor Factory by Using Prioritized Planning and Improved Ant Algorithm Zhang, Yi; Wang, Fuli; Fu, Fukang; Su, Zuqiang
Journal of Engineering and Technological Sciences Vol 50, No 4 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Multiple automated guided vehicle (multi-AGV) path planning in manufacturing workshops has always been technically difficult for industrial applications. This paper presents a multi-AGV path planning method based on prioritized planning and improved ant colony algorithms. Firstly, in dealing with the problem of path coordination between AGVs, an improved priority algorithm is introduced, where priority is assigned based on the remaining battery charge of the AGVs, which improves the power usage efficiency of the AGVs. Secondly, an improved ant colony algorithm (IAC) is proposed to calculate the optimal path for the AGVs. In the algorithm, a random amount of pheromone is distributed in the map and the amount of pheromone is updated according to a fitness value. As a result, the computational efficiency of the ant colony algorithm is improved. Moreover, a mutation operation is introduced to mutate the amount of pheromone in randomly selected locations of the map, by which the problem of local optimum is well overcome. Simulation results and a comparative analysis showed the validity of the proposed method.

Sliding Wear Properties of a Composite of Aluminum 2024 Powder Reinforced with Heat Treatment and Silicon Carbide Mahdi, Ahmed Sahib
Journal of Engineering and Technological Sciences Vol 50, No 5 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Wear behavior of aluminum alloy 2024 was investigated. Three patterns of specimens, namely, fabricated (compacted), reinforced with silicon carbide only and reinforced with silicon carbide followed by heat-treatment (quenching and aging processes) were selected. The effect of load on the specimen was studied for each type of pattern. Three values of load (10, 12.5 and 15N) were tested to investigate the wear behavior. The experimental results showed that the weight loss was 0.056 g for the specimen reinforced with silicon carbide and heat treatment, while it was 0.069 and 0.067 g for the as-fabricated specimen and the specimen reinforced with silicon carbide only, respectively. The increase of microhardness caused increased wear resistance and thus the weight loss was reduced. The microhardness increased with the increase of the ratio of silicon carbide, while, conversely, the density decreased with the increase of the ratio of silicon carbide. The maximum value of hardness was observed for the specimen reinforced with 5% of Sic followed with heat treatment at 284 Hv, while for the specimens reinforced with 4% and 3% Sic it was 255 and 227 Hv, respectively. It can be concluded that when heat treatment and reinforcement by Sic particles are performed, the microhardness value of aluminum 2024 will increase.

On-the-fly Computation Method in Field-Programmable Gate Array for Analog-to-Digital Converter Linearity Testing Mangca, Darwin C.; Gerasta, Olga Joy; Luna, Anne Lorraine; Zhu, Xi; Hora, Jefferson Abelo
Journal of Engineering and Technological Sciences Vol 50, No 5 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

This paper presents a new approach to linearity testing of analog-to-digital converters (ADCs) through on-the-fly computation in field-programmable gate array (FPGA) hardware. The proposed method computes the linearity while it is processing without compromising the accuracy of the measurement, so very little overhead time is required to compute the final linearity. The results will be displayed immediately after a single ramp is supplied to the device under test. This is a cost-effective chip testing solution for semiconductor companies, achieved by reducing computing time and utilization of low-cost and low-specification automatic test equipment (ATE). The experimental results showed that the on-the-fly computation method significantly reduced the computation time (up to 44.4%) compared to the conventional process. Thus, for every 100M 12-bit ADC tested with 32 hits per code, the company can save up to 139,972 Php on electricity consumption.

The Integration of MAFMA and AHP Methods for Analysis and Risk Mitigation of Pasteurized Milk Production Santoso, Imam; Sa’adah, Miftahus; Sari, Eva Novita; Prameswari, Puspa Ayu Indah; Agustina, Chintya Rizki
Journal of Engineering and Technological Sciences Vol 50, No 5 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Risk and uncertainty management is an important task in industry. Risks in raw materials such as livestock products may occur from the feed. The production process is also exposed to risks, which may be caused by controllable variables. In final products, uncontrollable actions may also pose risks. This research aimed to figure out the risks and their causes in the production process of milk and to discover applicable mitigation strategies. The methods used in this study were the Multi-Attribute Failure Mode Analysis (MAFMA) method to find the causes and Analytic Hierarchy Process (AHP) to discover mitigation strategies. The results were in the form of risks in the production process caused by: 1) raw materials, 2) the production process, 3) human resources, and 4) machinery and equipment. The highest risk in the production process is posed by undetected damage to machinery and contamination during the production process. However, both are rooted in human error: poorly trained workers, omission of checking or testing, and poor supervision of the process. Mitigation strategies, i.e. standardization and supervision of the raw materials, production process, and final product, were implemented to reduce the potential risks. In the implementation of these strategies, worker participation, either as controller or as supervisor, is very important.

Use of Systematic Approach in Accident Risk Analysis for Motorcyclists: A Conceptual Idea da Costa, Don Gaspar Noesaku; Malkhamah, Siti; Suparma, Latif Budi
Journal of Engineering and Technological Sciences Vol 50, No 5 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Thus far, minimum stopping sight distance (SSD) is determined based on design speed, a minimum reaction time of 1.64 s and a deceleration rate of 3.4 m/s², whereas in certain situations the latter can be shorter than 1 s and higher than 4.5 m/s². Awareness of this can trigger speculative behavior, as can be seen from the choice of speed and/or the critical crossing gap, which is often smaller than the recommended minimum SSD. This study focused on the development of an appropriate minimum SSD model that is suited to risky conditions at an un-signalized intersection and its possible usage in accident risk evaluation, particularly for motorcyclists. The data were taken from direct measurements and related studies. Variables that potentially influence minimum SSD were tested. The results strongly suggest that the speed reduction achieved by downshifting significantly influences both the braking distance and the impact speed. Moreover, the minimum SSD obtained from the proposed model significantly differs from that obtained from a similar model recommended by AASHTO. Therefore, it is worthwhile to consider the application of the proposed minimum SSD as an accident probability indicator parameter.

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