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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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Remediation of Cu in the Contaminated Soil by Using Equisetum debile (Horsetail)* Rahmaniar, Irna; Kamil, Idris Maxdoni
Journal of Engineering and Technological Sciences Vol 47, No 2 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Paddy fields in the Rancaekek area, Bandung Regency-Indonesia, has been contaminated by textile wastewater. The area needs to recover back to its normal condition and function. Several compounds were found in the soil, such as Cu, Zn, Pb, Cd, Co, Ni, and Cr. Phytoremediation was selected as a site remediation strategy, which employs plants to remove non-volatile and immiscible soil contents. The objective of the study was to determine the ability of Equisetum debile to absorb Cu from the contaminated soil. Cu measurement was conducted by using the AAS (Atomic Absorption Spectrophotometer) method. The study has shown that Equisetum debile can absorb Cu concentrations of up to 25.3 ppm in 60 days after initial planting. However, the Enrichment Coefficient value (0.392) indicated that Equisetum debile was not efficient as a hyperaccumulator plant.

Classifying Water Quality of Wando and Tamari According to the Characterization of H2O Stable Isotope and Ionized Type in the Middle and Lower Kiso River* Matsumoto, Yoshitaka; Nakanishi, Genki; Sagawa, Shiro; Inoue, Takanobu; Yokota, Kuriko
Journal of Engineering and Technological Sciences Vol 47, No 2 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Wando and tamari are water bodies in the floodplain of a river and play an important role in maintaining valuable ecosystems. There are over 100 wando and tamari in the middle and lower basin of the Kiso River. An Acheilognathus longipinnis, Itasenpara Bitterling, which is designated as an endangered species, has been identified in these areas. The habitat of these valuable wando and tamari species is endangered by the development of large land plants around these reservoirs caused by river dredging for flood protection. Therefore, it is essential to collect detailed data about the habitat, hydraulic water flow, physical structures and landscape in order to preserve this species, but so far little attention has been given to water quality. The purpose of our research was to classify the water quality of wando and tamari water, especially ions, and to determine the water type based on its origin. Samples were collected at 10 wando sites and 15 tamari sites from August 2011 to February 2013 along the Kiso River. As our analysis by trilinear diagram shows, the waters of wando and tamari almost all belong to the category of Type I (Ca-HCO3), which forms in shallow aquifers. The two reservoirs that do not belong to Type I are presumably contaminated by drainage water from human activities.

Bacteria as Self-Healing Agent in Mortar Cracks Nugroho, Ananto; Satyarno, Iman; Subyakto, Subyakto
Journal of Engineering and Technological Sciences Vol 47, No 3 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

This study was aimed at finding the possibility to apply Bacillus subtilis integrated into mortar matrix to act as a self-healing agent to seal cracks. Bacterial spores at concentrations of 104, 105, and 106 cells/ml were directly added into pulverized fly ash as medium to protect bacteria in high alkaline conditions. The results show that the addition of Bacillus subtilis spores into the mortar mixture enhanced the compressive strength, especially at a cell concentration of 105 cells/ml. The bacterial mortar had a small ability to recover the stiffness of the mortar, amounting to 34.85% of its original stiffness. The effectiveness of crack sealant and resistance to water flow were limited to a maximum crack width size of 0.22 mm. Physical observation showed that the bacterial mortar is characterized by calcite precipitation as a product of ureolytic bacteria. The quantity and distribution of calcite precipitate depended on the precipitation weight, gravity direction and oxygen availability. Meanwhile, chemical analysis using XRD and EDX showed that the bacterial mortar had a better crystallinity.

Quantitative Prediction of Coalbed Gas Content Based on Seismic Multiple-Attribute Analyses Pan, Renfang; Gao, Huanhuan; Lei, Kehui; Zhu, Zhengping
Journal of Engineering and Technological Sciences Vol 47, No 4 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Accurate prediction of gas planar distribution is crucial to selection and development of new CBM exploration areas. Based on seismic attributes, well logging and testing data we found that seismic absorption attenuation, after eliminating the effects of burial depth, shows an evident correlation with CBM gas content; (positive) structure curvature has a negative correlation with gas content; and density has a negative correlation with gas content. It is feasible to use theÂ hydrocarbon index (P*G) and pseudo-Poisson ratio attributes for detection of gas enrichment zones. Based on seismic multiple-attribute analyses, a multiple linear regression equation was established between the seismic attributes and gas content at the drilling wells. Application of this equation to the seismic attributes at locations other than the drilling wells yielded a quantitative prediction of planar gas distribution. Prediction calculations were performed for two different models,Â one using pre-stack inversionÂ andÂ the other one disregarding pre-stack inversion. A comparison of the results indicates that both models predicted a similar trend for gas content distribution, except that the model using pre-stack inversion yielded a prediction result with considerably higher precision than the other model.

Molecular Weight and Structural Properties of Biodegradable PLA Synthesized with Different Catalysts by Direct Melt Polycondensation Lee, Hyung Woo; Insyani, Rizki; Prasetyo, Daniel; Prajitno, Hermawan; Sitompul, Johnner P.
Journal of Engineering and Technological Sciences Vol 47, No 4 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Production of biodegradable polylactic acidÂ (PLA)Â from biomassbased lactic acid is widely studied for substituting petro-based plasticsÂ or polymers. This study investigated PLA production from commercial lactic acid in a batch reactor by applying a direct melt polycondensation method with two kinds of catalyst,Â Î³-aluminium(III)Â oxideÂ (Î³-Al2O3) orÂ zinc oxide (ZnO),Â in reduced pressure. The molecular weight of the synthesized PLA was determined by capillary viscometry and its structural properties were analyzed by functional group analysis using FT-IR. The yields of polymer production with respect to the theoretical conversion were 47% for Î³-Al2O3 and 35% for ZnO. However, the PLA from ZnO had a higher molecular weight (150,600 g/mol) than that from Î³-Al2O3 (81,400 g/mol). The IR spectra of the synthesized PLA from both catalysts using polycondensation show the same behavior of absorption peaks at wave numbers from 4,500 cm-1 to 500 cm-1, whereas the PLA produced by two other polymerization methods â polycondensation and ring opening polymerization âshowed a significant difference in % transmittance intensity pattern as well as peak area absorption at a wave number of 3,500 cm-1 as âOH vibration peak and at 1,750 cm-1 as âC=O carbonyl vibrational peak.

Analytical Study of Wind Influence on In-Flight Sprinkler Droplets Dwomoh, Frank; Shouqi, Yuan; Hong, Li
Journal of Engineering and Technological Sciences Vol 47, No 3 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

An analytical model to describe the dynamics of in-flight droplets is presented in this paper to augment information on wind influence on travel distance of in-flight sprinkler droplets. The model is ballistic-theory based. It employs a relatively simple, wide-range empirical relationship between drag coefficient and Reynoldsâ number to replace the several sets of relations for a specified range of Reynolds numbers. The fourth-order Runge-Kutta numerical integration techniques were used to solve the trajectory equations. A modified exponential model for droplet size distribution was used during the simulation. Comparative analysis showed that agreement exists between the predictions of this model and that of earlier models. Droplets with a diameter smaller than 0.1 mm travelled farthest. Within the droplet range of 0.5 mm to 4.5 mm, as droplet diameter increased, travelled distance increased with increasing wind speed. The extent of drift increased sharply within the droplet range of 0.5 mm to 0.05 mm and increased mildly for droplet diameters greater than 0.5 mm. The model also attempts to identify droplets that are likely to contribute to drift loss and those that have a high probability of contributing only to distortion of the distribution pattern.

Improved Wavelet Threshold De-noising Method Based on GNSS Deformation Monitoring Data Gao, Yandong; Xu, Maolin; Yang, Fengyun; Mao, Yachun; Sun, Shuang
Journal of Engineering and Technological Sciences Vol 47, No 4 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

In the process of GNSS deformation monitoring, it is inevitable that the monitoring data are contaminated by noise. Effectively mitigating the impact of noise on the measurements and thus improving the quality of the deformation data is the objective of GNSS data processing. Wavelet analysis can analyse the signal according to different frequencies of the signal. Simulation data can be used to determine the best wavelet basis function and select the appropriate decomposition level. In this paper, an improved threshold de-noising method is proposed, based on an analysis of conventional hard threshold de-noising, soft threshold de-noising and compulsory de-noising methods. The improved method was examined through a simulation analysis and applied in an engineering case. The results show that it effectively removed the noise at high frequencies while retaining data details and mutation. The de-noising ability of the proposed technique was better than that of the conventional methods. Moreover, this method significantly improved the quality of the deformation data.

Kinetic Study on Ultrasound Assisted Biodiesel Production from Waste Cooking Oil Widayat, Widayat; Hadiyanto, H; Sasongko, Setia Budi
Journal of Engineering and Technological Sciences Vol 47, No 4 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

The objective of this research was to studyÂ a kinetic model of biodiesel production from waste cooking oil assisted by ultrasound power. The model considered the biodiesel production process as a 2nd order reversible reaction, while its kinetic parameters were estimated using MATLAB, based on data extracted from Hingu, et al. [1]. The data represented experiments under low-frequency ultrasonic wave (20 kHz) and variations of temperature, power, catalyst concentration, and alcohol-oil molar ratio. Statistical analysis showed that the proposed model fits well to the experimental data with a determination coefficient (R2) higher than 0.9.

Development of Indoor Air Pollution Concentration Prediction by Geospatial Analysis Yudison, Adyati P.; Driejana, R.
Journal of Engineering and Technological Sciences Vol 47, No 3 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

People living near busy roads are potentially exposed to traffic-induced air pollutants. The pollutants may intrude into the indoor environment, causing health risks to the occupants. Prediction of pollutant exposure therefore is of great importance for impact assessment and policy making related to environmentally sustainable transport. This study involved the selection of spatial interpolation methods that can be used for prediction of indoor air quality based on outdoor pollutant mapping without indoor measurement data. The research was undertaken in the densely populated area of Karees, Bandung, Indonesia. The air pollutant NO2 was monitored in this area as a preliminary study. Nitrogen dioxide concentrations were measured by passive diffusion tube. Outdoor NO2 concentrations were measured at 94 locations, consisting of 30 roadside and 64 outdoor locations. Residential indoor NO2 concentrations were measured at 64 locations. To obtain a spatially continuous air quality map, the spatial interpolation methods of inverse distance weighting (IDW) and Kriging were applied. Selection of interpolation method was done based on the smallest root mean square error (RMSE) and standard deviation (SD). The most appropriate interpolation method for outdoor NO2 concentration mapping was Kriging with an SD value of 5.45Â Âµg/m3 and an RMSE value of 5.45Â Âµg/m3, while for indoor NO2 concentration mapping the IDW was best fitted with an RMSE value of 5.92 Âµg/m3 and an SD value of 5.92 Âµg/m3.

On the Development of a Nomogram for Alkali Activated Fly Ash Material (AAFAM) Mixtures Simatupang, Partogi H.; Imran, Iswandi; Pane, Ivindra; Sunendar, Bambang
Journal of Engineering and Technological Sciences Vol 47, No 3 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Alkali activated fly ash material (AAFAM) has become the most promising material to substitute materials based on ordinary Portland cement (OPC). However, there is no available nomogram for AAFAM mixtures. In contrast, there are many rational methods available in the literature to make paste, mortar and concrete with OPC based materials, such as Monteiro-Heleneâs nomogram, which uses Abramâs law, Lyseâs law and Molinariâs law. This paper presents a study to construct such a nomogram for AAFAM mixtures by first conducting experiments on theÂ paste and mortar phases. The procedure of Monteiro-Heleneâs nomogram was adopted in this formulation. The first step in this direction was to find a close relationship between the strength and paste composition of the material that can be used as a substitute for Abramâs law. The second stepÂ wasÂ to construct the equivalentÂ ofÂ Lyseâs and Molinariâs relationships by varying the sand and fly ash contents. The results show that it is possible to make a nomogram for AAFAM mixtures such as the one for OPC based materials. Class F fly ash and its mortar phase were used to construct the nomogram. In addition, theÂ mortarÂ samplesÂ that wereÂ used to build the nomogram had similar solidification products according to their microscopic characteristics.

Page 20 of 127 | Total Record : 1267

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