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INDONESIA
Journal of Engineering and Technological Sciences
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 – 2012) Proceedings ITB on Engineering Science (2003 - 2007) Proceedings ITB (1961 - 2002)
Arjuna Subject : -
Articles 1,267 Documents
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Fabrication of Microporous Water Filter Using Titanium Dioxide Particles, Silica Particles, and Polyethylene Glycol Priatama, Aris; Abdullah, Mikrajuddin; Khairurrijal, Khairurrijal; Mahfudz, Hernawan
Journal of Engineering and Technological Sciences Vol 42, No 1 (2010)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (561.473 KB) | DOI: 10.5614/itbj.eng.sci.2010.42.1.3

Abstract

We report the fabrication of microporous filter for use in filtering both inorganic  and  organic  substances  from  liquid  materials.  Titania  (TiO 2)  anatase was  used  as  the  main  material  for  this  filter.  Polyethylene  glycol  (PEG)  with average  molecular  weight  of  20,000  was  also  used  as  additive  to  control  the formation  of  pores,  especially  pore  sizes.  The  mixture  of  titania  and  PEG  was pressed into cylindrical tablet shape at room temperature  and then simply heated inside a furnace up to temperature where the PEG decomposed into gas to leave only connected titania particles. The use of titania as base material for the filter allows  the  organic  substances  that  trapped  inside  the  filter  pores  to  be  easily removed by heating up the used filter at above decomposition temperature of the trapped  organics.  We  also  made  other  filter  by  adding  small  amount  of  silica (SiO2)  particles  to  reduce  the  size  of  the  pores  as  well  as  to  improve  the mechanical  strength.  We  observed  that  filters  containing  silica  particles,  with smaller  in  size  compared  to  titania,  resulted  in  better  mechanical  strength, smaller in pore sizes and better filtering results in term of turbidity and dissolved oxygen (DO) content. This  method is potential for development of larger scale and cheaper water filters for use in various applications.
Utilization of Cassava Starch in Copolymerisation of Superabsorbent Polymer Composite (SAPC) Abidin, Akhmad Z.; Puspasari, Tiara; Graha, Hafis Pratama Rendra
Journal of Engineering and Technological Sciences Vol 46, No 3 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (871.442 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.3.4

Abstract

Cassava starch was used as the main chain in the copolymerization of a superabsorbent polymer composite (SAPC) based on acrylic acid and bentonite. The SAPC was synthesized through graft polymerization using nano-sized bentonite as reinforcement. The variables in this experiment were: bentonite concentration, acrylic acid to starch weight ratio, concentration of initiator, and cross linker. The product was characterized using FTIR, SEM and TGA-DSC. The results show that the polymerization reactions involved processes of incorporating starch chains as polymer backbone and grafting acrylic acid monomers onto it. The use of cassava starch in the polymerisation produced a very short reaction time (10-15 minutes), which led to SAPC production with higher efficiency and lower cost. Bentonite interacts with monomers via hydrogen and weak bonding, thus improving the thermal properties of the product. The maximum absorbance capacity obtained was at an acrylic acid to starch weight ratio of 5 and a concentration of initiator, cross linker and bentonite of 0.5, 0.05 and 2 weight percent, respectively. The product is suitable for agricultural and medical applications as well as common superabsorbent polymer applications.
Optimization of Laccase Production using White Rot Fungi and Agricultural Wastes in Solid-State Fermentation Risdianto, Hendro; Sofianti, Elis; Suhardi, Sri Harjati; Setiadi, Tjandra
Journal of Engineering and Technological Sciences Vol 44, No 2 (2012)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (349.682 KB) | DOI: 10.5614/itbj.eng.sci.2012.44.2.1

Abstract

Abstract. Laccase has been produced in a solid-state fermentation (SSF) process using white rot fungi and various  lignocellulose-based substrates.  The white  rot fungi  used  were  Marasmius  sp.,  Trametes  hirsuta,  Trametes  versicolor  and Phanerochaete  crysosporium.  The  solid  substrates  employed  in  this  research were collected from  agricultural  waste, specifically  empty fruit bunches (EFB), rice  straw,  corncobs  and  rice  husks.  The  objective  of  this  research  was  to determine  the  most  promising  fungus,  the  best  solid  substrate  and  the  optimal conditions for the production of laccase.  The  results showed that  Marasmius  sp. on all solid substrates displayed  a  higher laccase activity than that of  any  other strain  of  white  rot  fungi.  Marasmius  sp.  and  a  solid  substrate  of  rice  straw demonstrated  the  highest  laccase  activity  of  1116.11  U/L  on  day  10.  Three significant  factors,  i.e.  pH,  temperature  and  yeast  extract  concentration,  were studied by  the  response surface method on laccase production using  Marasmius sp.  and rice straw. The optimized conditions were  a  pH, temperature and yeast extract concentration of 4.9, 31ºC and 0.36 g/L,  respectively.  The fermentation of  Marasmius  sp.  in  SSF  on agricultural  waste  shows  a  great  potential  for  the production of laccase.
A Low-Dimensional Model for the Maximal Amplification Factor of Bichromatic Wave Groups Tan, W. N.; Andonowati, Andonowati
Journal of Engineering and Technological Sciences Vol 35, No 2 (2003)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (601.672 KB) | DOI: 10.5614/itbj.eng.sci.2003.35.2.4

Abstract

We consider a low-dimensional model derived from the nonlinear-Schrödinger equation that describes the evolution of a special class of surface gravity wave groups, namely bichromatic waves. The model takes only two modes into account, namely the primary mode and the third order mode which is known to be most relevant for bichromatic waves with small frequency difference. Given an initial condition, an analytical expression for the maximal amplitude of the evolution of this initial wave group according to the model can be readily obtained. The aim of this investigation is to predict the amplification factor defined as the quotient between the maximal amplitude over all time & space and the initial maximal amplitude. Although this is a problem of general interest, as a case study, initial conditions in the form of a bichromatic wave group are taken. Using the low dimensional model it is found that the least upper bound of the maximal amplification factor for this bichromatic wave group is √2. To validate the analytical results of this model, a numerical simulation on the full model is also performed. As can be expected, good agreement is observed between analytical and numerical solutions for a certain range of parameters; when the initial amplitude is not too large, or when the difference of frequency is not too small. The results are relevant and motivated for the generation of waves in hydrodynamic laboratories.
The Identification of Fishing Ground Area with MODIS Satellite Image (Case Study: South Coast of West Java) Hakim, Dudung Muhally; Wikantika, Ketut; Widiadnyana, Nengah; Napitu, Asmi M.; Darmawan, Soni
Journal of Engineering and Technological Sciences Vol 38, No 2 (2006)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (759.449 KB) | DOI: 10.5614/itbj.eng.sci.2006.38.2.5

Abstract

 According to UNCLOS, Indonesian marine territorial covers an area equal to around 2.8 million square kilometers inner archipelagic seas. Though the Indonesian water region is very wide, the resource within it is not yet been exploited optimally. Indonesia still has problems that have to be copped with, including identification of marine fishing ground areas. This report proposes a technology to make the fish-catching be more efficient and effective with the help of MODIS satellite image in term of Surface Temperature and chlorophyll-a computation. Data conversion from digital number to Water Brightness Temperature are performed. The determination of potential fishing ground area were conducted based on temperature and chlorophyll-a parameters which serve as an indicator of upwelling and observations were carried out on parameters which show this phenomenon. Based on the result, during May 2004 the upwelling process were not happened yet, and it seems to occur in June 2004. It showes by the decreasing of water temperature in South Coast of West Java particularly between the border of West Java and Central of Java. This phenomenon acts as an indicator for the raising of primer productivity and will takes about one month after upwelling to the bloom of phytoplankton.
Geometry Effect Investigation on a Conical Chamber with Porous Media Boundary Condition Using Computational Fluid Dynamic (CFD) Technique Bindar, Yazid
Journal of Engineering and Technological Sciences Vol 41, No 2 (2009)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (521.447 KB) | DOI: 10.5614/itbj.eng.sci.2009.41.2.1

Abstract

The present study is an attempt to introduce  a  method for optimizing the  geometry  of  a  unit  process.  The  comprehensive  unit  process  performances are generated by a  CFD engine. The CFD engine can simulate the unit process performances  at  whatever  conditions.  Both  design  geometry  and  operating variables were used on the CFD simulation. The burden on a simplified process was taken out from CFD simulation. A complex geometry of a unit process is represented  by  a  secondary  reformer.  A  secondary  reformer  has  a  conical chamber  as a space to undergo  a  combustion reaction before entering  a  catalyst bed. This complexity is added by the boundary  on a  porous solid surface as the top surface of  the catalyst bed. The  conical  angle affects the flow pattern inside the  conical chamber  having a porous solid surface as its  base. The  conical  angle above  65° results  the  disappearing  of  the recirculation  flow.  The  inlet  distance from  the  porous  solid  surface  also  can  exhibit  different  characteristics  of recirculation  flow.  The  closer  the  distance  to  the  porous  solid  surface,  the stronger the recirculation is. The inlet velocity values have no significant effect on  the  flow  pattern.  The  introduction  of  a  solid  volume  inside  the  geometry creates distortion in the flow pattern. In the application, the inserted solid volume is equivalent to a burner. It means that the use of the burner inherently produces some problems of the flow distribution.
H∞ Control of Polynomial Fuzzy Systems: A Sum of Squares Approach Wibowo, Bomo S.; Trilaksono, Bambang Riyanto; Syaichu-Rohman, Arief
Journal of Engineering and Technological Sciences Vol 46, No 2 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (402.033 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.2.3

Abstract

This paper proposes the control design ofa nonlinear polynomial fuzzy system with H∞ performance objective using a sum of squares (SOS) approach. Fuzzy model and controller are represented by a polynomial fuzzy model and controller. The design condition is obtained by using polynomial Lyapunov functions that not only guarantee stability but also satisfy the H∞ performance objective. The design condition is represented in terms of an SOS that can be numerically solved via the SOSTOOLS. A simulation study is presented to show the effectiveness of the SOS-based H∞ control designfor nonlinear polynomial fuzzy systems.
A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation Rajab, Abdul; Sulaeman, Aminuddin; Sudirham, Sudaryatno; Suwarno, Suwarno
Journal of Engineering and Technological Sciences Vol 43, No 3 (2011)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (663.106 KB) | DOI: 10.5614/itbj.eng.sci.2011.43.3.3

Abstract

Mineral  oil  is  known  to  have  a  low  biodegradability  level  and  high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm  oil  with  mineral  type  insulating  liquid  and  silicone  oil.  The  measured parameters  were  breakdown  voltage,  dissipation  factor  (tan  δ),  and  dielectric constant.  Breakdown  voltage  measurement  was  performed  in  accordance  with IEC  156  standard,  whereas,  the  dissipation  factor  and  dielectric  constant measurement  were  conducted  based  on  IEC  60247  standard  test  methods.  The results  showed  that  variations  of  dielectric  properties  of  palm  oil  to  the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation  factors  of  all  tested  oils  were  increased,  while  their  dielectric constants were slightly decreased with the increase of temperature.
Study on Rayleigh Wave Inversion for Estimating Shear-wave Velocity Profile Sanny, T. A.; Avianto, Yoes
Journal of Engineering and Technological Sciences Vol 35, No 1 (2003)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1067.003 KB) | DOI: 10.5614/itbj.eng.sci.2003.35.1.2

Abstract

Rayleigh wave or ground roll is a noise in seismic body waves. However, how to use this noise for soil characterization is very interesting since Rayleigh wave phase velocity is a function of compression-wave velocity, shear-wave velocity, density and layer thickness. In layered-medium Rayleigh wave velocity also depends on wavelength or frequency, and this phenomenon is called dispersion. Inversion procedure to get shear-wave velocity profile needs a priori information about the solution of the problem to limit the unknown parameters. The Lagrange multiplier method was used to solve the constrained optimization problems or well known as a smoothing parameter in inversion problems. The advantage of our inversion procedure is that it can guarantee the convergence of solution even though the field data is incomplete, insufficient, and inconsistent. The addition of smoothing parameter can reduce the time to converge. Beside numerical stability, the statistical stability is also involved in inversion procedure. In field experiment we extracted ground roll data from seismic refraction record. The dispersion curves had been constructed by applying f-k analysis and f-k dip filtering. The dispersion curves show the dependence of Rayleigh wave phase velocities in layered media to frequency. The synthetic models also demonstrate the stability and the speed of inversion procedure.
Ribotyping Identification of Thermophilic Bacterium from Papandayan Crater Akhmaloka, Akhmaloka; Suharto, A.; Nurbaiti, S.; Tika, I. N.; Warganegara, F. M.
Journal of Engineering and Technological Sciences Vol 38, No 1 (2006)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (334.31 KB) | DOI: 10.5614/itbj.eng.sci.2006.38.1.1

Abstract

A few thermophilic bacteria were isolated from a hot spring located in Papandayan Crater, Garut. One of the organisms showed a well growth at temperature of up to 80 oC. Chromosomal DNA from the organism was isolated and used to amplify 16S rRNA gene fragment. The gene was amplified by a set of universal primers (27F and 1492R) resulting in a 1.5 kb DNA fragment. The gene was cloned and sequenced. The phylogenetic tree, homological analysis, and detailed comparison of the sequences showed that 16S rRNA gene sequence of the Papandayan isolate is unique compared to other known strains, however the sequence had closest similarities with Bacillus caldolyticus and Bacillus caldotenax.

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