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INDONESIA
Makara Journal of Technology
Published by Universitas Indonesia
ISSN : -     EISSN : -     DOI : -
Core Subject : Science,
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Articles 7 Documents
Search results for , issue " Vol 9, No 2 (2005)" : 7 Documents clear
Simultaneous Treatment of Organic (Phenol) and Heavy Metal (Cr6+ or Pt4+) Wastes over TiO2, ZnO-TiO2 and CdS-TiO2 Photocatalysts Slamet, Slamet; Arbianti, Rita; Daryanto, Daryanto
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.99

Abstract

Treatment of heavy metal (Cr6+ and Pt4+) and organic (phenol) wastes has been studied using the relatively new method, i.e. simultaneous photocatalytic process over TiO2 photocatalysts in the batch photoreactor. Following the photocatalytic reduction of the heavy metal wastes, recovery of Cr and Pt was carried out by precipitation and leaching method, respectively.  The experimental results show that in the simultaneous photocatalytic system, there is a synergism effect between the photocatalytic reduction of heavy metal waste (Cr6+ or Pt4+) and the oxidation of organic waste (phenol), so that increasing the conversion of each other. Dopant of ZnO with the optimum loading (0.5 wt%) could slightly increase the performance of TiO2 photocatalyst in photocatalytic treatment of the wastes. Whereas CdS dopant with the optimum loading of 1 wt% could significantly enhance the  performance of TiO2 photocatalyst in simultaneous Cr(VI) reduction and phenol oxidation with the highest conversion of ≥ 97 % and 93 %, respectively. Photocatalytic reduction of Pt(IV) under 0.5%ZnO-TiO2 and 1%CdS-TiO2 photocatalysts effectively occurred with a high conversion (> 99 %) in 2 hours irradiation of UV. The optimum precipitation condition of Cr(III) recovery was achieved at pH = 9, with the efficiency of recovery was 91 %. Optimum temperature of leaching process in Pt recovery was 100 oC, with the efficiency of recovery was 86 %.
Design and Implementation of 1-2 GHz Stepped Frequency GPR for Buried Metal Detection Suryana, Joko; Suksmono, Andriyan; Mengko, Tati
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.100

Abstract

In this paper, we describe the design and realization steps of 1 - 2 GHz SFGPR (Stepped Frequency Ground Penetrating Radar) transceiver for metal detection under the ground. Before using prototyped GPR for detecting the metal under the ground, several of calibration processes must be performed, namely phase calibration and monocycle pulse waveform calibration. After completing the calibrations, this prototyped GPR would be ready for detecting a  hidden object such as a metal plate 5 cm under the ground in our small test range size 25 cm x 75 cm x 10 cm. From the calibration and detection results, we concluded that the prototyped SFGPR passed the technical specifications of the design and could perform the metal detection under the ground with high SNR.
Development of Low Frequency Vibration Method of Direct-Write Deposition Relevant to Layer Manufacturing Application Widyanto, Susilo; Tontowi, Alva; Jamasri, Jamasri; Budi Rochardjo, Heru Santoso
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.101

Abstract

The research of deposition process is the first step in development process of multi materials selective laser sintering. The deposition process enables to settle multi materials powder in horizontal formation on one layer. In this research we use low frequency (70 - 200Hz) to vibrate a hopper nozzle in which powder is settled. The research method consists of two steps, the first step is to determine flow-ability parameters and the second is to join flow ability parameter with other parameters such that the line width can be controlled. The results show that the line width depends on uniformity of particle size, particle size, frequency of vibration, deposition gap, particle shape and feed-rate of hopper-nozzle.
Design of Generating Dual Frequency Operation for Triangular Microstrip Antenna Using Electromagnetic Coupling Surjati, Indra; Rahardjo, Eko; Hartanto, Djoko
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.97

Abstract

A new design is proposed in this paper by applying a pair of slits using a microstrip feed line. Therefore the microstrip line feeding system is electromagnetically coupled to the patch. The antenna works at two different frequencies in the range from 2 GHz to 4 GHz (S band frequency). The results of the simulation shows that the dual frequency operation can be created when the slit width is 1 mm and the height of the slits ranges from 10 mm to 14 mm with inter slit distance of 3 mm, 5 mm and 7 mm as well.
Production Hydrogen And Nanocarbon Via Methane Decomposition Using Ni-Based Catalysts. Effect Of Acidity And Catalyst Diameter Purwanto, Widodo; Nasikin, M; Saputra, E; Song, L
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.102

Abstract

Objectives of this research are mainly to study impacts of acidity strength (by varying amount of precipitant and loading Al-Si) and the effect of nickel particle size (by varying calcinations temperature) on decomposition reaction performances. In this research, high-nickel-loaded catalyst is prepared with two methods. Ni-Cu/Al catalysts were prepared with co-precipitation method. While the Ni-Cu/Al-Si catalyst were prepared by combined co-precipitation and sol-gel method. The direct cracking of methane was performed in 8mm quartz fixed bed reactor at atmospheric pressure and 500-700°C. The main  results showed that the Al content of catalyst increases with the increasing amount of precipitant. The activity of catalyst increases with the increasing of catalysts acidity to the best possible point, and then increasing of acidity will reduce the activity of catalyst. Ni-Cu/4Al and Ni-Cu/11Al deactivated in a  very short time hence produced fewer amount of nanocarbon, while Ni-Cu/15Al was active in a very  long period. The most effective catalyst is Ni-Cu/22Al, which produced the biggest amount of nanocarbon (4.15 g C/g catalyst). Ni catalyst diameter has significant effect on reaction performances mainly  methane conversion and product yield. A small Ni crystal size gave a high methane conversion, a fast deactivation and a low carbon yield. Large Ni particle  diameter yielded a slow decomposition and low methane conversion. The highest methane  conversion was produced by catalyst diameter of 4 nm and maximum yield of carbon of 4.08 g C/ g catalyst was achieved by 15.5 nm diameter of Ni catalyst.
Synthesis of Fuel Cell Membrane: Copolymerization of Styrene on ETFE Film by Grafted pre-Irradiation Yohan, Yohan; Nur, Rifaid; Hendrajaya, Lilik; Siradj, E. S.
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.98

Abstract

Preirradiation Grafting styrene monomer on ETFE  film has been prepared. Research has been  performed by γ-ray radiation at various total dose from 2.5 - 12.5 kGy and various dose rate from 1.3 - 1.9 kGy/hour. Irradiated copolymer is then grafted by styrene monomer in various solvent: ethanol, 2-propanol, and toluene, various concentration from 20 - 70% volume, various temperature from 50 - 90oC, and various grafting time from 2 - 12 hours. The results showed that percent of grafting is increase with increase of total dose and decrease of  rate dose. The optimum experiment conditions are obtained at total dose 10 kGy, dose rate 1,9 kGy/hour, 2-propanol solvent, 40% volume styrene, 4 hours grafting time, and 70oC grafting temperature.
Design of Product Placement Layout In Retail Shop Using Market Basket Analysis Surjandari, Isti; Seruni, Annury
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.7454/mst.v9i2.103

Abstract

Retailing is an industry with high level of competition.  It is a customer-based industry which depends on how it could be aware of what the customers needs and requirements are. One technique most used in supermarkets is the mix merchandise. The purpose of this paper is to identify associated products, which then grouped in mix merchandise with the use of market basket analysis. This association between products then will be applied in the design layout of the product in the supermarket. The process of identifying the related products bought together in one transaction is done by using data mining  technique. Apriori algorithm is chosen as a method in the data mining process. Using WEKA (Waikato Environment for Knowledge Analysis) software, the association rule between products is calculated. The results found five category association rules and fourteen sub-category association rules. These associations then will be interpreted as confidence and support to become consideration for the product layout.

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