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Makara Journal of Technology
Published by Universitas Indonesia
ISSN : 23552786     EISSN : 23564539     DOI : https://doi.org/10.7454/mjt
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering Engineering Materials Science & Nanotechnology Mechanical Engineering
MAKARA Journal of Technology is a peer-reviewed multidisciplinary journal committed to the advancement of scholarly knowledge and research findings of the several branches of Engineering and Technology. The Journal publishes new results, original articles, reviews, and research notes whose content and approach are of interest to a wide range of scholars. It also offers rapid dissemination. MAKARA Journal of Technology covers the recent research in several branches of engineering and technology include Electrical & Electronics Engineering, Computer Engineering, Mechanical Engineering, Chemical & Bioprocess Engineering, Material & Metallurgical Engineering, Industrial Engineering, Civil & Architecture Engineering, and Marine Engineering. Criteria used in determining acceptability of contributions include newsworthiness to a substantial part of the engineering & technology and the effect of rapid publication on the research of others. This journal, published three times each year, is where readers look for the advancement of discoveries in engineering and technology.
Arjuna Subject : Teknik (semua kategori) - Teknik (Lain-Lain)
Articles 17 Documents
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Search results for , issue "Vol. 14, No. 2" : 17 Documents clear
Dye Sensitized Solar Cell with Conventionally Annealed and Post-Hydrothermally Treated Nanocrystalline Semiconductor Oxide TiO2 Derived from Sol-Gel Process Yuwono, Akhmad Herman; Munir, Badrul; Ferdiansyah, Alfian; Rahman, Arif; Handini, Wulandari
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

Dye-sensitized solar cell (DSSC) is one of the very promising alternative renewable energy sources to anticipate the declination in the fossil fuel reserves in the next few decades and to make use of the abundance of intensive sunlight energy in tropical countries like Indonesia. In the present study, TiO2 nanoparticles of different nanocrystallinity was synthesized via sol−gel process with various water to inorganic precursor ratio (Rw) of 0.85, 2.00 and 3.50 upon sol preparation, followed with subsequent drying, conventional annealing and post-hydrothermal treatments. The resulting nanoparticles were integrated into the DSSC prototype and sensitized with an organic dye made of the extract of red onion. The basic performance of the fabricated DSSC has been examined and correlated to the crystallite size and band gap energy of TiO2 nanoparticles. It was found that post-hydrothermally treated TiO2 nanoparticles derived from sol of 2.00 Rw, with the most enhanced nanocrystalline size of 12.46 nm and the lowest band gap energy of 3.48 eV, showed the highest open circuit voltage (Voc) of 69.33 mV.
An Empirical Model for Build-Up of Sodium and Calcium Ions in Small Scale Reverse Osmosis Nasir, Subriyer
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and reject streams using Atomic Absorption Spectrophotometer (AAS). Multiple linear regression of natural logarithmic transformation was used to develop the model based on four main parameters that affect the build-up of solute in a small scale of RO namely applied pressure, permeate flux, membrane resistance, and feed concentration. Experimental data obtained in a small scale RO unit were used to develop the empirical model. The predicted values of theoretical build-up of sodium and calcium on membrane surface were found in agreement with experimental data. The deviation in the prediction of build-up of sodium and calcium were found to be 1.4 to 10.47 % and 1.12 to 4.46%, respectively.
The Effect of Enzymatic Hydrolysis on The Properties of Protein Hydrolysate from Paddy Mushroom Palupi, Niken Widya; Windrati, Wiwik Siti; Tamtarini, Tamtarini
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

Protein hydrolysate was prepared from Paddy (Volvariella volvaceae) mushroom. Hydrolysis uses commercially protease available Protamex ™ with enzyme concentration of 0.1% (w/w). Hydrolysis was performed at three different temperatures (room temperature, 40 °C, and 50 °C) with different incubation periods (60, 90, and 120 minutes). Enzyme inactivation was done in 90 °C for 3 minutes. Yield and degree of hydrolysis ranged from 94.76% to 99.55% and 19.06% to 24.59%. Protein solubility was about 89–11,8%. The longer time of hydrolysis, the darker the color of protein hydrolysate. Protein hydrolysate which has hydrolysis at 50 °C for 120 minutes has the highest protein yield and the best sensory properties: 4.76 (taste liking), 3.68 (aroma liking), and 4.56 (overall liking). However, this protein hydrolysate has the potential for application as an ingredient in formulated diets.
Effect of Diafiltration on Preparation of Fermented Mung Beans Concentrate as Probiotic Savory Flavor Through Ultrafiltration Membrane Aspiyanto, Aspiyanto; Susilowati, Agustine
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

Diafiltration by means of the ultrafiltration system of probiotic fermented Mung beans (Phaseolus radiatus L.) concentrate has been performed to reduce or eliminate salts and smaller impurities than the nominal cut-off of the membrane of 20,000 nominal weight cut-off (NWCO). These processes have been conducted as an attempt in order to get a probiotic product with organoleptic acceptability, composition, and the optimal total lactic acid bacteria (LAB) counts because the presence of salts will affect on the viability of LAB and the cell lysis of LAB and limit its utility in food products. Concentrate of probiotic mung beans was prepared through fermentation of LAB using inoculum of LAB consisting of Lactobacillus bulgaricus and Streptococcus thermophylus (1 : 1) on fermented mung beans extract inoculated by inoculum of Rhizopus–C1 in rice substrates at salt condition. Ultrafiltration and diafiltration modes have been carried out at flow rate of 8.77 Liter/minute, room temperature and the pressure of 5 bar (0 to 79.7 minutes) and 7 bar (0-154.5 minutes) with the ratio of the volume of pure water to the volume of initial feed (number of diavolume, Nd) of 0, 0.25, 0.5, 0.75, 1.0 and 1.25, respectively. The experiment results based on total LAB counts as a probiotic product show that a high Nd can reduce the salt content but increase the total LAB counts. Nd of 1.0 results reduce the salt content which is equal to retentate, permeate, and the optimal total LAB counts. Ultrafiltration and diafiltration modes at the pressure of 7 bar and Nd of 1.0 give a retentate with total solid of 6.1355%, salt of 1.3515% and remove 86.15% of the salt from probiotic fermented mung beans concentrate and total LAB counts of 10.73 log cycles. Meanwhile, the permeate obtained at this condition results in flux value of 10.83 Liter/m2.hour with contents of total solid of 6.8199%, salt of 1.325% and total LAB counts of 5.49 log cycles.
Immobilization of Saccharomyces Cerevisiae in Rice Hulls for Ethanol Production Martini, Edita; Andriani, Dian; GobiKrishnan, Sriramulu; Kang, Kyeong Eop; Bark, Surn-Teh; Sunwoo, Changshin; Prasetya, Bambang; Park, Don-Hee
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

The whole cell immobilization in ethanol fermentation can be done by using natural carriers or through synthetic carriers. All of these methods have the same purpose of retaining high cell concentrations within a certain defined region of space which leads to higher ethanol productivity. Lignocellulosic plant substance represents one of highly potential sources in ethanol production. Some studies have found that cellulosic substances substances can also be used as a natural carrier in cell immobilization by re-circulating pre-culture medium into a reactor. In this experiment, rice hulls without any treatment were used to immobilize Saccharomyces cerevisiae through semi solid state incubation combined with re-circulating pre-culture medium. The scanning electron microscopy (SEM) pictures of the carrier show that the yeast cells are absorbed and embedded to the rice hull pore. In liquid batch fermentation system with an initial sugar concentration of 50 g/L, nearly 100% total sugar was consumed after 48 hours. This resulted in an ethanol yield of 0.32 g ethanol/g glucose, which is 62.7% of the theoretical value. Ethanol productivity of 0.59 g/(L.h) is 2.3 fold higher than that of free cells which is 0.26 g/(L.h). An effort to reuse the immobilized cells in liquid fermentation system showed poor results due to cell desorption in the first batch which led to high sugar concentration inhibitory effect in the second batch fermentation. This might be solved by using semi solid fermentation process in the future work.
Plant Growth Modeling Using L-System Approach and Its Visualization Suyantohadi, Atris; Alfiyan, Alfiyan; Hariadi, Mochamad; Purnomo, Mauridhi Hery
Makara Journal of Technology Vol. 14, No. 2
Publisher : UI Scholars Hub

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Abstract

The visualization of plant growth modeling using computer simulation has rarely been conducted with Lindenmayer System (L-System) approach. L-System generally has been used as framework for improving and designing realistic modeling on plant growth. It is one kind of tools for representing plant growth based on grammar sintax and mathematic formulation. This research aimed to design modeling and visualizing plant growth structure generated using L-System. The environment on modeling design used three dimension graphic on standart OpenGL format. The visualization on system design has been developed by some of L-System grammar, and the output graphic on three dimension reflected on plant growth as a virtual plant growth system. Using some of samples on grammar L-System rules for describing of the charaterictics of plant growth, the visualization of structure on plant growth has been resulted and demonstrated.
Remote Sensing and Geographical Information System to Identify Drought Potency Raharjo, Puguh Dwi
Makara Journal of Technology Vol. 14, No. 2
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Abstract

Remote Sensing and Geographical Information System to Identify Drought Potency. Kebumen regency was drought in year 2008, community clean water shortages and irrigation water following a decline in water resources. The use of remote sensing data and GIS can be used to identify the potential for drought-prone areas. Transformation of Landsat TM satellite imagery to obtain the brightness index, wetness index and vegetation index used to determine surface conditions in relation to drought. Brightness index and wetness index derived from the tasseled cap modifications, while the vegetation index derived from normalized difference vegetation index (NDVI) values. Other parameters such as aquifer conditions, rainfall and other types of dry agricultural land use was a factor in identifying drought. The data are performed in accordance with the zone description in order to get the study area in relation to regional drought. The result of the research is identified area the district of Karangsambung, Karanggayam, Sadang, Alian, Puring, Klirong, Buluspesantren, Ambal and Mirit potential drought.
WiMAX Implementation as Existing Hotspot Network Backhaul in Jakarta Sirat, Djamhari; Asvial, Muhamad; Marpaung, Luther B.
Makara Journal of Technology Vol. 14, No. 2
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Abstract

WiMAX Implementation as Existing Hotspot Network Backhaul in Jakarta The development of Broadband Wireless Access (BWA), such as WiMAX, as a global standard for data transmission media has been used by high speed internet access provider. WiMAX application which supported by capabilities of interoperability, flexibility and commercial aspect make the internet services become more efficient, cheaper and easier to the customer. This phenomenon should be responded by ISPs. Based on technical and financial aspect in deciding the implementation of Wireless Network with WiMAX technology as a substitute, this research will observe and analyze the projection of WiMAX technology implementation as a backhaul for the existing Wi-Fi’s network in Jakarta. This paper will describe the calculation based on the amount of hotspots registered in IIX and average peak traffic per regional from technical aspect with several pricing and technology combination. The result give the basic figures in investing WiMAX as substitute technology for backhaul in hotspot network and also will show its growth in 5 years.
Separation Study of Titanomagnetite Fe3-xTixO4 from Natural Sand at Indramayu, West Java Sunaryo, Sunaryo; Sugihartono, Iwan
Makara Journal of Technology Vol. 14, No. 2
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Separation Study of Titanomagnetite Fe3-xTixO4 from Natural Sand at Indramayu, West Java. Titanomagnetite FeTiO4 has been obtained from metal sand which is separated from natural sand at Indramayu using magnetic separator with the magnetic field 0,3 Tesla. This method can improve titanomagnetite content from 32% to 63,6%. According to X-ray diffractometer (XRD) and data processing by general structure analyses system (GSAS) with χ2= 1,454 and Wrp = 0,1142 as correction factor of the peak to peak intensities, we conclude that χ2 about 0 and Wrp aproximately 10%. It indicates the datas with the error merely 0,1 can be accepted. Furthermore, HCl 32% and NH4OH 25% were added into separation result in order to increase titanomagnetite content. While X-ray flouresence (XRF) analyses shows weight fraction of titanomagnetite increase up to 100%.
Hydrogen Absorption Induced Slow Crack Growth in Austenitic Stainless Steels for Petrochemical Pressure Vessel Industries Rusli, Ronnie Higuchi
Makara Journal of Technology Vol. 14, No. 2
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Abstract

Type 304L and type 309 austenitic stainless steels were tested either by exposed to gaseous hydrogen or undergoing polarized cathodic charging. Slow crack growth by straining was observed in type 304L, and the formation of α‘ martensite was indicated to be precursor for such cracking. Gross plastic deformation was observed at the tip of the notch, and a single crack grew slowly from this region in a direction approximately perpendicular to the tensile axis. Martensite formation is not a necessary condition for hydrogen embrittlement in the austenitic phase.

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