Purwokerto, Indonesia
Purwokerto, Indonesia

The Jenderal Soedirman University is a State University located in Purwokerto, Indonesia that was established on September 23, 1963. The university named after Jenderal Soedirman, the first commander-in-chief of the Indonesian Army during the country's fight for independence; he was born in the Banyumas region. The university rector is Prof. Edy Yuwono, PhD.UNSOED is the only State University in ex Banyumas residency. Thus affecting the student composition, from 25,782 of total active students in 2008, students from local Banyumas region accounted for almost 35% while the rest are from other regions in Indonesia as far as Sumatera and Sulawesi. About 5000 students enrolled at the university every year. Continuing development and improvement in education and student facilities and UNSOED's location in Purwokerto, a peaceful and cozy city, make it very suitable as a place for study, attracting more fresh high school graduates from all regions in Indonesia. The university also established a good reputation in the fields of Agriculture, Law, and Biology research and applied science.To improve overall services for the students, UNSOED provided many facilities and activities such as students economic union , scholarships, medical services and medical infrastructure, life insurance, libraries, laboratory, student learning center, student activity center, web-based academic information system, academic infrastructure , arts and sports organizations and dormitory. Wikipedia.

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Sulaeman U.,Jenderal Soedirman University | Sulaeman U.,Tohoku University | Yin S.,Tohoku University | Sato T.,Tohoku University
Applied Catalysis B: Environmental | Year: 2011

Chromium (Cr)-doped SrTiO3 nanoparticles were synthesized by a microwave-assisted solvothermal reaction using SrCl2·6H2O and Ti(OC3H7)4 as starting materials in KOH methanol-oleic acid solution. The products were characterized by XRD, TEM, BET surface area, and XPS. The photocatalytic activity was determined by DeNOx ability using LED lamps with wavelengths of 627nm (red), 530nm (green), 445nm (blue) and 390nm (UV). The nanoparticles of perovskite type Cr-doped SrTiO3 with a particle size of 15-20nm were successfully synthesized. The photocatalytic activity of SrTiO3 for DeNOx ability under visible light (627nm) irradiation was able to be improved by doping with a small amount of Cr. The high photocatalytic activity of Cr-doped SrTiO3 in the visible region was caused by new absorption in the visible region. © 2011 Elsevier B.V.

Suroso,Jenderal Soedirman University | Noguchi T.,University of Shizuoka
Energy Conversion and Management | Year: 2010

This paper presents a novel topology of a three-level current-source PWM inverter totally driven by using single gate-drive power supply used for a grid connected inverter. The great feature of the proposed inverter circuit is that all of the power switches are connected on common-source or common-emitter configuration. Using this common-source current-source inverter (CS-CSI) the number of gate-drive power supply can dramatically be reduced into only a single power source without using bootstrap technique or many isolated power supplies. Operation of the proposed new inverter was tested by using computer simulation and experimentally. The simulation and experimental results proved that the inverter works properly generate a three-level output current waveform and inject a sinusoidal current into power grid with unity power factor operation. During grid connected operation, almost all harmonic orders are suppressed by using an additional harmonic suppression technique. © 2010 Elsevier Ltd. All rights reserved.

Suroso,Jenderal Soedirman University | Noguchi T.,University of Shizuoka
IET Power Electronics | Year: 2011

The study proposes a new circuit configuration of multilevel current-source inverter (CSI). In this new multilevel CSI topology, all power switching devices of the inverter are connected at a common-emitter point or at a common-potential line. Hence, all the power switches need only a single gate drive power supply without using isolated power supplies or conventional bootstrap techniques. This feature is still valid even if the number of the power switches increases owing to the higher-level number of the output current waveform. As a result, complexity of the gate drive circuit can be remarkably moderated. In addition, the multilevel CSI circuit is more capable to operate at high switching frequency if required, because all the power switches are connected at a common potential level. A five-level pulse width modulation inverter configuration, including chopper circuits as DC current-power source circuits using small smoothing inductors, is verified through computer simulations and experimental tests. The results show feasibility of the proposed multilevel inverter topology with reducing the complexity of the gate drive circuits, the inductor size, total harmonic distortion (TMD) of output current and increasing the efficiency of the multilevel CSI. © 2011 The Institution of Engineering and Technology.

Suroso,Jenderal Soedirman University | Noguchi T.,University of Shizuoka
Telkomnika | Year: 2012

In a high switching frequency operation of current-source inverter (CSI), a conventional way to obtain unidirectional power switches is by connecting discrete diodes in series with the high speed power switches, i.e. power MOSFETs or IGBTs. However, these discrete diodes will cause extra losses to the power converter. This paper presents experimental test results of high switching frequency five-level common-emitter CSI using the emerging unidirectional power switches, i.e. reverse blocking (RB)-IGBTs. Experimental tests were also conducted to compare the performance between power MOSFETs in series with the discrete diodes, and the RB-IGBTs having inherent reverse blocking capability. The results show that using RB-IGBTs, the efficiency of the power converter increase. However, it is also confirmed that the recently available RB-IGBTs have slow reverse recovery current than the discrete fast-recovery diodes connected in series with power MOSFETs. © 2012 Universitas Ahmad Dahlan.

Suroso,Jenderal Soedirman University | Suroso,Nagaoka University of Technology | Noguchi T.,University of Shizuoka
IEEE Transactions on Power Electronics | Year: 2012

This paper presents a new circuit configuration of single-phase multilevel current-source inverter (CSI). In this new topology, a basic H-bridge CSI working as a main inverter generates a multilevel current waveform in cooperation with inductor cells connected in parallel as auxiliary circuits. Each inductor cell is composed by four unidirectional power switches with an inductor across the cell circuit. The inductor cells work by generating the intermediate level of the multilevel current waveform with no additional external dc-power sources. A simple proportional-integral controller is applied to control the intermediate-level currents of the multilevel output waveform. A five-level and a nine-level pulsewidth-modulation inverter configuration, with chopper-based dc-current sources, are verified through computer simulations. Furthermore, an experimental prototype of a five-level CSI is set up and is tested. The results show that the test circuit works properly to generate the multilevel output-current waveform with low output harmonics by using small size of inductors without any additional external dc-power sources, which proves feasibility of the proposed strategy. © 2011 IEEE.

Meinita M.D.N.,Jenderal Soedirman University | Meinita M.D.N.,Pukyong National University | Hong Y.-K.,Pukyong National University | Jeong G.-T.,Pukyong National University
Bioprocess and Biosystems Engineering | Year: 2012

Red seaweed, Kappaphycus alvarezii, holds great promise for use in biofuel production due to its high carbohydrate content. In this study, we investigated the effect of fermentation inhibitors to the K. alvarezii hydrolysate on cell growth and ethanol fermentation. In addition, detoxification of fermentation inhibitors was performed to decrease the fermentation inhibitory effect. 5-Hydroxymethylfurfural and levulinic acid, which are liberated from acidic hydrolysis, was also observed in the hydrolysate of K. alvarezii. These compounds inhibited ethanol fermentation. In order to remove these inhibitors, activated charcoal and calcium hydroxide were introduced. The efficiency of activated charcoals was examined and over-liming was used to remove the inhibitors. Activated charcoal was found to be more effective than calcium hydroxide to remove the inhibitors. Detoxification by activated charcoal strongly improved the fermentability of dilute acid hydrolysate in the production of bioethanol from K. alvarezii with Saccharomyces cerevisiae. The optimal detoxifying conditions were found to be below an activated charcoal concentration of 5%. © Springer-Verlag 2011.

Meinita M.D.N.,Jenderal Soedirman University | Meinita M.D.N.,Pukyong National University | Hong Y.-K.,Pukyong National University | Jeong G.-T.,Pukyong National University
Bioprocess and Biosystems Engineering | Year: 2012

Abstract In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and byproducts. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 °C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.© Springer-Verlag 2011.

Maryani S.,Jenderal Soedirman University
Mathematical Methods in the Applied Sciences | Year: 2015

In this paper, we prove the global well-posedness of non-Newtonian viscous fluid flow of the Oldroyd-B model with free surface in a bounded domain of N-dimensional Euclidean space RN(N≥2). The assumption of the problem is that the initial data are small enough and orthogonal to rigid motions. © 2015 John Wiley & Sons, Ltd.

Maryoto A.,Jenderal Soedirman University
Procedia Engineering | Year: 2015

Most of the water used in the concrete evaporates after the concrete hardens. Due to this processes, there are millions of capillaries in the hardened concrete. Consequently, concrete is a porous material. The liquids and gases enter into the concrete through the capillaries. Penetrability of the fluids into the concrete can be reduced using some methods. One of them is using additives which increase hydrophobic property of concrete. Hydrophobic action in the concrete can be achieved by adding stearic acid. This study tries to investigate effect of Ca (C18H35O2)2 (calcium stearate) in the microstructures of the concrete. Five contents of calcium stearate is utilized which are 0, 1, 2, 3, and 4 kg in one cubic meter of concrete mix. Three testing model which are compressive stress test, permeability test and macro cell corrosion test, are conducted in order to study the effect of calcium stearate in the concrete. Each testing model consists of 15 specimens. Cylinder with 150 mm diameter and 300 mm height, cube 150 mm × 150 mm × 150 mm and beam with 280 mm length, 224 mm width and 152 mm height are tested for compressive stress, permeability and macro cell corrosion respectively. The results show that usage of calcium stearate tend to increase compressive stress of concrete until the content of calcium stearate is 4 kg, but the increasing is insignificant. Concrete with 3 kg of calcium stearate produces the minimum value of permeability and macro cell corrosion. Based on the result, it can be concluded that calcium stearate improves microstructures of concrete. © 2015 The Authors. Published by Elsevier Ltd. Published by Elsevier Ltd.

Tri Cahyanto W.,Jenderal Soedirman University
Advanced Materials Research | Year: 2014

Adsorption mechanism of carbon monoxide (CO) on PtRu and PtRuMo alloy surfaces is investigated by using a density functional theory (DFT). It includes evaluation of binding configuration and the adsorption strength. The results show that CO preferentially adsorbs onto the 3 fold hollow site of the PtRu- surface, while on the PtRuMo surface we observe the shift from the fcc hollow site to near the bridge site. We also note that adsorption energy of CO on the PtRuMo is stronger than that of adsorption on the PtRu surface. From the charge transfer analysis, we conclude that the stronger binding energy is caused by the more charge transferred to the surfaceadsorbate bonding region brought by alloying Mo to the PtRu. © (2014) Trans Tech Publications, Switzerland.

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