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IPTEK The Journal for Technology and Science
Published by Institut Teknologi Sepuluh Nopember Surabaya
ISSN : 08534098     EISSN : 20882033     DOI : -
Core Subject : Science,
Computer Science & IT
IPTEK The Journal for Technology and Science (eISSN: 2088-2033; Print ISSN:0853-4098), is an academic journal on the issued related to natural science and technology. The journal initially published four issues every year, i.e. February, May, August, and November. From 2014, IPTEK the Journal for Technology and Science publish three times a year, they are in April, August and December in online version.
Arjuna Subject : -
Articles 345 Documents
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The Anticancer Activity of Marine Sponge Cinachyrella sp. (Family Tetillidae) Awik Puji Dyah Nurhayati; Rarastoeti Pratiwi; Subagus Wahyuono; Istriyati Istriyati; Nichole J de Voogt
IPTEK The Journal for Technology and Science Vol 25, No 3 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i3.530

Abstract

Cinachyrella sp. marine sponge produce many kinds of secondary metabolites. The purpose of this study was to examine the cytotoxic and anti-proliferative activity of marine sponge Cinachyrella sp. The sponge was extracted with 96 % ethanol. Ethanol extract cytotoxicity assay were performed with MTT method (Microculture Tetrazolium) against to cell lines of HeLa, T47D, WiDr and Vero. The results show that of the ethanol extract were only toxic to cell lines of HeLa IC50 897.809 μg/mL but did not toxic to cell lines of T47D, WiDr and normal cell lines of Vero. Fractionation of the ethanol extract was conducted by a Vacuum Column Chromatography (VCC) and have 4 fraction that were F1, F2, F3 and F4. Cytotoxicity and cell proliferation inhibitory were tested of fraction F1, F2, F3 and F4 against cell lines of T47D. The values IC50 of F1; F2; F3 and F4 against cell lines of T47D were 82.744; 163.679; 66.522 and 333.026 μg/mL and fraction F3 concentration 31.5 µg/mL inhibits cell proliferation cell lines of T47D at 48 hours of incubation
Eccentric Digraph of Cocktail Party Graph and Hypercube Tri Atmojo Kusmayadi; Nugroho Arif Sudibyo
IPTEK The Journal for Technology and Science Vol 22, No 4 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i4.74

Abstract

Let G be a graph with a set of vertices V(G) and a set of edges E(G). The distance from vertex u to vertex v in G, denoted by d(u, v), is the length of the shortest path from vertex u to v. The eccentricity of vertex u in graph G is the maximum distance from vertex u to any other vertices in G, denoted by e(u). Vertex v is an eccentric vertex from u if d(u, v) = e(u). The eccentric digraph ED(G) of a graph G is a graph that has the same set of vertices as G, and there is an arc (directed edge) joining vertex u to v if v is an eccentric vertex from u. In this paper, we determine the eccentric digraph of a class of graph called the cocktail party graph and hypercube.
Performance Analyse of Air Mixed and Displacement Ventilatilation System in Office Room Base on Computational Fluid Dynamic Bambang Iskandariawan; Paulus Indiyono; Herman Sasongko; Prabowoa Prabowo
IPTEK The Journal for Technology and Science Vol 20, No 2 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i2.127

Abstract

Air ventilation system is required for improvement as well as maintenance room air circumstance which is always clean in the whole day. Effective ventilation will enhance thermal comfort and indoor air quality therefore the productivity of occupant is expected also becomes mo-re intense. This research deals with the influence of supply air diffuser position concerning to thermal comfort and in-door air quality viewpoints. It is inspected four categories of air ventilation system: mixed and displacement ventila-tion used for air supply diffuser position in the centre and at the side of the room. Thermal comfort aspect is demons-trated through velocity and temperature of the room air without considering the value of relative humidity and room surface temperature average). On the other side the indoor air quality is focused on the intensity of the CO2 gas concentration which is appear inside the room gas. It applies Fluent 6.2 as computational fluid dynamics (CFD) simulation, some research variables are exploited. Office room model is generated in GAMBIT software create par-ticular office room design. Analyse result prove that the displacement centre ventilation system has more capability in the handling of room heat in addition to contaminant gas compare to the others.
A Comparison between Buck-Boost Inverter with and without Buffer Inductor Purwadi Agus Darwito; Soebagio Soebagio; Mauridhi Hery Purnomo
IPTEK The Journal for Technology and Science Vol 23, No 2 (2012)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v23i2.8

Abstract

The electric vehicle inverter requires an induction motor drive with a high output of voltage and current to reduce the number of batteries used and in turn reduce the vehicle’s weight. In this paper compared two single Phase BuckBoost Inverter (SPBBI), that is between the SPBBI conventional topology with SPBBI new topology uses a buffer inductor. The results of comparison are expected that the new inverter topology can strengthen the voltage greater than the conventional inverter topology. The inverter’s components of capacitor and inductor were reconfigured. The circuit was simulated for various carrier and signal frequencies with various load. The simulation results of the proposed topology compared with the simulation results of conventional topologies commonly used in a variety of frequency and load values. It is shown that the output voltage and current can be strengthened significantly, with a value of more than five times of the output voltage compared to the conventional inverter. The new inverter topology is useful to be implemented for the electric vehicle.
Slurry Dewatering Process to Improve Quality of Low Grade Coal Hartiniati Hartiniati
IPTEK The Journal for Technology and Science Vol 18, No 4 (2007)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v18i4.163

Abstract

The upgrading Kalimantan low rank coal is performed using slurry dewatering process in a stirred batch autoclave (inner volume of 5 liters) equipped with a condenser, a pressure control valve (PCV), and a receiver. The experiment is carried out at 3.5 kg/cm2G nitrogen pressure, 250oC heater temperature and 150 rpm agitator speed. Kerosene and low sulfur waxy residue (LSWR) are used as oil solvents. The fluidity of slurry is studied with the ratio of oil to coal (O/C) at 1.5 to 2 wt/wt and the concentration of LSWR at 0.5 to 2% in oil. The temperature profile during operation is evaluated to investigate the process performance. Moreover, pH, TSS and TDS contents in water product is also analyzed. A centrifuge separator (cap. 200 gram, 1000 rpm) is used to remove oil in coal slurry, and it is found that almost all added oil can be recovered. The study suggests that calorific value of upgraded coal (as received basis) increases sharply from 5,178 kcal/kg to 7342 kcal/kg, following drastic reduction in total moisture, from 25,5% to 4,97%. The contents of ash, volatile matter and elements do not change very much from that of raw coal. This phenomenon shows that no chemical reaction occurs in the process. The wastewater from the process is clean enough thereby a simple wastewater treatment is required in commercial plant. Re-absorption test shows that stable moisture content in coal is achieved at 7.5 wt% for 13 days. The temperature profile suggests that the slurry dewatering process can be applied effectively to Kalimantan low rank coals producing excellent upgraded coal characteristics.
Approximations of the Generalized Log-Logistic Distribution to the Chi-Square Distribution Kartika Candra Buana; Warsono Warsono; Dian Kurniasari
IPTEK The Journal for Technology and Science Vol 25, No 1 (2014)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v25i1.478

Abstract

The main purpose of this article is to do approximations graphically and mathematically the four-parameter generalized log-logistic distribution, denoted by G4LL(α,β,m_1,m_2), to the one-parameter Chi-square distribution with υ degrees of freedom. In order to achieve this purpose, this article creates graphically the probability density functions of both distribution and derives mathematically the MGF of the both distributions. To prove the MGF of Chi-square as a special case of the MGF of G4LL distribution, we utilized an expansion of the MacLaurin series. The results show that graphically, the Chi-square distribution can be approximated by the generalized log-logistic distribution. Moreover, by letting α=1,β=-ln⁡(2m_2 ),m_1=v/2 and m_2→∞, the MGF of the G4LL distribution can be written in the form of the MGF of the Chi-square distribution. Thus, the Chi-square distribution is a limiting or special case distribution of the generalized log-logistic distribution.The main purpose of this article is to do approximations graphically and mathematically the four-parameter generalized log-logistic distribution, denoted by G4LL(α,β,m_1,m_2), to the one-parameter Chi-square distribution with υ degrees of freedom. In order to achieve this purpose, this article creates graphically the probability density functions of both distribution and derives mathematically the MGF of the both distributions. To prove the MGF of Chi-square as a special case of the MGF of G4LL distribution, we utilized an expansion of the MacLaurin series. The results show that graphically, the Chi-square distribution can be approximated by the generalized log-logistic distribution. Moreover, by letting α=1,β=-ln⁡(2m_2 ),m_1=v/2 and m_2→∞, the MGF of the G4LL distribution can be written in the form of the MGF of the Chi-square distribution. Thus, the Chi-square distribution is a limiting or special case distribution of the generalized log-logistic distribution.
Application of Interval Type-2 Fuzzy Logic System in Short Term Load Forecasting on Special Days Agus Dharma; Imam Robandi; Mauridhi Hery Purnomo
IPTEK The Journal for Technology and Science Vol 22, No 2 (2011)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v22i2.65

Abstract

This paper presents the application of Interval Type-2 fuzzy logic systems (Interval Type-2 FLS) in short term load forecasting (STLF) on special days, study case in Bali Indonesia. Type-2 FLS is characterized by a concept called footprint of uncertainty (FOU) that provides the extra mathematical dimension that equips Type-2 FLS with the potential to outperform their Type-1 counterparts. While a Type-2 FLS has the capability to model more complex relationships, the output of a Type-2 fuzzy inference engine needs to be type-reduced. Type reduction is used by applying the Karnik-Mendel (KM) iterative algorithm. This type reduction maps the output of Type-2 FSs into Type-1 FSs then the defuzzification with centroid method converts that Type-1 reduced FSs into a number. The proposed method was tested with the actual load data of special days using 4 days peak load before special days and at the time of special day for the year 2002-2006. There are 20 items of special days in Bali that are used to be forecasted in the year 2005 and 2006 respectively. The test results showed an accurate forecasting with the mean average percentage error of 1.0335% and 1.5683% in the year 2005 and 2006 respectively.
S Velocity Probing of Ontong-Java Plateau by Analyzing Seismograms of B041196C Earthquake Bagus J. Sentosa
IPTEK The Journal for Technology and Science Vol 20, No 3 (2009)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v20i3.107

Abstract

This research investigates the S wave velocity structure under Ontong-Java Plateau in Equator Western Pacific using seismogram analysis of B041196F earthquake at various observatory stations. The analyzed wave phases are the S wave, Love and Rayleigh surface wave phases and core reflected ScS and ScS2 wave phases. Seismogram comparison shows different discrepancies that depend on the azimuth direction from hypocenter. South East area of OJP has positive anomaly that differs from the other previously seismological research in the same area. Eastwards area of OJP has negative anomaly like the other result of seismological research. On other azimuth direction indicates that positive anomaly occurred not only in the upper mantle but also at mantle layers till CMB.
Converter Ac-to-Ac With Additional Free- Wheeling Switches for Improving Power Factor and Reducing Harmonic Distortion Mochamad Ashari1
IPTEK The Journal for Technology and Science Vol 19, No 2 (2008)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v19i2.153

Abstract

This paper presents development of single phase AC-to-AC converter with additional free-wheeling switches for improving the power factor and reducing harmonic distortion. The proposed system uses 2 switching types: the main switch and additional switch. The main switch is for controling the amplitude of the output voltage, while the additional switch is for releasing energy from inductive loads (free-wheeling switch). The main swicth is controlled by pulse width modulation (PWM), and the additional switch is modulated using the line frequency, 50 Hz. An AC-to-AC converter was simulated and built for laboratory test purposes. A conventional system, using thyristor and called Phase Control, was simulated for the system comparison. Results from simulation and laboratory tests show that the proposed system works properly. Using the same loads, the conventional system presents power factor as 0,34–0,71 and the voltage THD as 62.1%. The proposed system provides an improved power factor at nearly unity, and presents the total harmonic distortion of the voltage as 2.45%.
An Analysis Nomoto Gain and Norbin Parameter on Ship Turning Maneuver Aulia Siti Aisjah
IPTEK The Journal for Technology and Science Vol 21, No 2 (2010)
Publisher : IPTEK, LPPM, Institut Teknologi Sepuluh Nopember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j20882033.v21i2.31

Abstract

First order approach of maneuvering ship model developed by Nomoto, that has commonly underpinned researchers on mathematical models of ship maneuvering, is employed by the present research in order to describe the results of Nomoto validation gain value from some type of ships. In this present study, the controls are designated using FLC, while the rules are derived from FLC; furthermore, the reference is the LQG/LTR. On the other pole, Norbin parameters are obtained under the bases of the gain and time constant output control response. Validation of Nomoto gain value is obtained through the calculation of the value of a constant gain, settling time of the first order response, and approach value toward damping ratio and natural frequency response of the system used to control the output of the second order pattern. Validation is employed on 20 types of ships with a length between 40-350 meters; as a result, it is figured out that at the Low Speed General Cargo ship, Mariner, RO/RO, and Barge Carrier have good maneuverability compared to the other 17 types of ships.

Page 13 of 35 | Total Record : 345

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