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INDONESIA
Sainstek
Published by Universitas Negeri Padang
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Education
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Articles 28 Documents
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Sistem Pengontrolan Temperatur ON-OFF Menggunakan Mikrokontroler AT89C51 dengan Pengindera Termokopel Syufrawardi, Syufrawardi; Yohandri, Yohandri; Asrizal, Asrizal
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

Temperature control system was an important instrument to control temperature of an object at setpoint temperature and many applications in human life. Investigation of control system was required to get high quality of system. Purposes of this research was: to investigate relation between output voltage of sensor and signal processing circuits with temperature, to determine number that presented at digital display as function of temperature, and to determine accuracy and precision of temperature control system. The research can be classified into laboratory experimental research. Data collecting technique that used in this research was direct measurement. Variables that measured temperature, output voltage of sensor, and output voltage of amplifier circuits, while gradient of straight line and static characteristics were measured indirectly. The data that  founded of measurement result was analyzed  by using graph and error analysis. Graph analysis was used to determine measurement error, accuracy, and precision of control system. There were four main results of this research as follow: 1). Output voltage of sensor  increase directly proportional with temperature and sensitivity of sensor was 0,042 Volt/oC, 2). Output voltage of differential and non inverting amplifier  also directly proportional with temperature, each of  it’s gradient was 0,0091 Volt/oC and 0,0248 V/oC, 3). The number that displayed at seven segment before linearization process directly proportional with temperature and after processing the number at digital display was suitable with temperature that measured by standard digital thermometer, and 4). The average of accuracy and precision of temperature control system by using microcontroller with thermocouple  sensing was high, each of it was 0,9967 and 0,997 in order of least significant scale was 1 oC. Key words : Control system, thermocouple, microcontroller, sensitivity, accuracy, precision.
Pemodelan Perilaku Dinamik Motor Induksi Tiga Fasa Ahyanuardi, Ahyanuardi
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

Dynamic performance induction motor had been need to analyze behavior induction motor except steady-state. The paper presents an investigation of transient performance of a three-phase squirrel-cage rotor induction motor. The underlying model technique chooses the stator and rotor d-q axis magnetic flux linkages as the state space variables.  The simulation of transient performance of the machine is examined for the starting process, and suddenly load. Typical results of the transient simulation are presented to suggest guidelines for really protection and control design problem identification of a squirrel-cage rotor three-phase induction motor. Key words: dinamic performance, transient performance, induction motor
PENENTUAN AKTIVITAS AMILASE DARI UMBI BENGKUANG (Pachyrrizus arosus L.Urb) HASIL EKSTRAKSI ETANOL DAN AMMONIUM SULFAT iswendi, Iswendi
Sainstek Vol 12, No 1 (2009): Vol. XII No. 1, September 2009
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

Amylase is an hydrolase enzyme that plays a role in the hydrolysis reaction of starch and glycogen into isomaltose, maltotriose, maltose and glucose. Amylase can be obtained by extraction from several sources of plants, animals and microorganisms. Extraction of the enzyme can be done in two ways, with an organic solvent and inorganic salt. We have conducted research on amylase activity of yam tubers extracted with ethanol and ammonium sulfate. This research aimed to determine the optimum amylase activity at the variations of temperature and pH, and the effectiveness of extractors. This research is an experimental research using complete randomized design with two factorials which are pH and temperature. pH variations were 4, 4.5, 5.0, 5.5, and 6, while the variation of temperature are 300 C, 400 C, 500C, and 600C. Isolation of amylase-was carried out by multilevel fractionation using saturated ammonium sulphate 40, 60. 80, and 90% w/v and cold ethanol 95%. Amylase activity was determined based on the concentration of glucose which is result of hydrolysis of starch by Nelson-Somogy method. The highest activity was found in fraction I, pH 4 and temperature of 500C with 34.55 units of activity for ethanol solvent and 30.72 units for ammonium sulfate. Keywords :     amylase, activity, extraction, yam tubers
Karakterisasi Genetik TRICHODERMA SPP Indigenus Rizosfir Pisang yang Berpotensi Pengendalian FUSARIUM OXYSPORUM F. SP. CUBENSE Penyebab Penyakit Layu Fusarium pada Pisang Nurbailis, Nurbailis; Martinius, Martinius
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

The objective of the research was to characterize the genetic variation of Trichoderma spp. Study of genetic characters used Random Amplified Polymorphic DNA-Polymerase Chain-reaction (RAPD-PCR) that amplicated with four primers (OPA 2, OPA 17, OPB- 05 and Primer 2).  Analysis result of genetic variation of Trichoderma spp make as dendrogram. The result of the research indicated that : 1) Trichoderma spp. had the great genetic variation, 2)Trichoderma isolate from the same region did not always have the same genetic profile, 3) S6 and T1 isolates were effective to inhibit the growth of Fusarium oxysporum f. Sp. cubense  than the others but  had a different genetic profile. Keywords : Trichoderma spp, Fusarium oxysporum f.sp.cubense, karakterisasi genetik
ANALISIS KARAKTERISTIK DAN PEMODELAN KEBUTUHAN PARKIR KENDARAAN FAKULTAS TEKNIK UNIVERSITAS NEGERI PADANG oktaviani, Oktaviani; Ashar, Faisal; Dwi Laksana, Putra
Sainstek Vol 12, No 1 (2009): Vol. XII No. 1, September 2009
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

The increasing number of academics on Faculty of Engineering, State University of Padang (FT-UNP) resulted in the provision of facilities parking space problem. This study aims to determine the characteristics of parking, how parking demand model and know the standards required parking. Data space requirements include primary data obtained from field surveys used to obtain the characteristics of the parking and secondary data obtained from the Bureau of Academic and Student Affairs Administration FT-UNP. Parking demand modeling performed by the method of simple linear regression analysis. Independent variables that are reviewed include: the number of FT-UNP academic community. While the dependent on variable is the highest accumulation of parking and parking accumulation on average. The analysis showed that, the car is a vehicle with the highest accumulation index 1.24, and accumulated an average of 0.71, the highest accumulation on motorcycle accumulated an average of 1.02 0.59. Model the relationship between the accumulation of a car park with the highest number of academic community is y = 11.987 + 0.008 x (R2 = 0.919) and accumulated an average of y = 11.717 + 0.005 x (R2 = 0.904). While the motorcycle to the highest accumulation of y = -12.812 + 0.096 x (R2 = 0.966) accumulated an average y = -18.793 + 0.065 x (R2 = 0.952). To determine the vehicle parking space requirements based on the number of the academic community in the year 2010 (5721 people) are: 58 parking lot (SRP) for car or 725 m2, and for motorcycle parking lot 536 or 750 m2. Key words : Ferroelektrik, BST, Spin Coating.
ISOLASI FLAVONOID DAN UJI BIO AKTIVITAS DARI TERUNG PIRUS (Cyphomandra betacea (Cav.) Sendtn) ellizar, Ellizar; Maaruf, Yustini
Sainstek Vol 12, No 1 (2009): Vol. XII No. 1, September 2009
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

This research was a flavonoid isolation to determine the characteristics and the bioactivities of  the Cyphomandra betacea (Cav) Sendtn. Flavonoid was known as a compound which contribute to physiological and pharmacological values to human. The compound was found in angiospermae, gymnospermae, and pteridopita. The flavonoid was also presumed can be used as a dyer and to protect human as medicines. The method of isolation by using maceration with methanol, then was  fractionated by using n-hexane and ethyl acetate. Ethyl acetate fraction seperated column chromatography by silica-gel 60, treated n-hexane: ethyl acetate and ethyl acetate: methanol as eluen. The purity of fraction was identified by KLT and the melting point. Pure flavonoid (58.1 mg) as white yellow needle crystal obtained has the interval range melting point as much 168. 4 to 169.90C. The bioactivity test of the flavonoid shows that the flavonoid  function as  antibacteria, but not function as antifungy. The flavonoid was assumed as O-glycoside flavon with OH at C-5, C-3’, C-4’ and prenil at  C-6. Key words:     flavonoid, dye, isolation, bioactivity & antibakteria
Efek konsentrasi Prekursor Terhadap SIFAT FISIK Film Tipis BASRTIO3 (BST) SRUKRUR MFM DAN MFS yang Ditumbuhkan dengan SPIN COATING Darvina, Yenni
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

An BST precursor was synthesized by mixing Barium acetate 99,9%, Strontium acetate 99,99% , Titanium isopropoxide 99,999% in 2-methoxyethanol 99,9% and acetic acid glasia 100% at 120oC along 3 hours. The BST precursor concentration were 0.1 M and 0.5 M.  By employing CSD method, the BST precursor was spin coated on p-type Si (100) substrate at 3000 rpm for 30 seconds and pyrolyzed at 130oC at 10 minutes to obtain BST thin films. The BST thin films were annealed for 15 hours at 1000oC. The BST thin films structure were MFM and MFS, characterized their physical properties. It was found that grain size and thickness for the MFM structure at the BST 0,1 M were < 0.3μm and 0.6 μm., And  the BST 0.5 M were 0.5–1.0 μm and 0.9 μm. Grain size and thickness for the MFM structure at the BST 0.1 M were < 0.3μm and 0.6 μm, for BST 0.5M were 0.5–1μm and 0.8 μm .Latis constant 3.936 Ǻ. Composition of BST thin films was  same as BST precursor. Key words : Ferroelektrik, BST, Spin Coating.
Perancangan dan Implementasi Controller Knowledge Base pada Pengendalian Kecepatan Motor Induksi Tiga Fasa Almasri, Almasri; Santoso, Agus
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

Designing a controller, the model  development is necessary. From the model will shown the relationship between plant response and models response expected. This research will try to make  plant of controller which has relationship  between plant response and the models response. From the plant response and models response will be made the rule base as the basic plant of knowledge based controller. Before making the rule base, the plant parameters must be identified. The plant of knowledge based will be implemented  for controlling three phase motor induction directly. From the relationship between plant response and the expected model. It’s easier to use knowledge based controller to mean some models we expected. The aim of this research is to obtain algorithms of knowledge base controller non-lenear base plant and model response expected, so that is obtained realtion really between the second response, which can controlled lenear and non-lenear plant and the stability of speed of the three phases induction motor is constant although change of load. Key Word : knowledge based controller, rule base, three phase motor induction
ISOLASI DAN KARAKTERISASI STRUKTUR FLAVONOID DARI TUMBUHAN SARIPATI (Clerodendron infortunatum Linn) isniyetti, Isniyetti
Sainstek Vol 12, No 1 (2009): Vol. XII No. 1, September 2009
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

A flavonoid of the Clerodendron infortunatum Linn has been isolated by ethylacetate fraction of its methanolic extract. Apigenin (5,4 ,dihydroksiflavon) was isolated by chromatography over silica gel with ethylacetate – hexane as eluent and then crystallized from ethylacatate – hexane to give the flavonoid as plates, m..p. 289-291 0C. The structure of which followed from its spectroscopic properties. Key word :      Flavonoid, elusidation, ethylacetate fraction, chromatografi, spectroscopic properties.
PENGARUH PENAMBAHAN TEPUNG KERABANG (CANGKANG TELUR) DALAM PROSES PENGOMPOSAN SAMPAH ORGANIK (SAMPAH RUMAH TANGGA) isniati, Isniati
Sainstek Vol 12, No 1 (2009): Vol. XII No. 1, September 2009
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

The increasing of resident growth has contributed to the increasing of yielded garbage volume. The increasing of garbage volume has various problems concerned to the esthetics and health of contamination due to environment. To avoid the mentioned garbage, it is required to be managed better so that become a benefit to environmental human being. The composting process can be quickened by addition of eggshell. This research aims to know the rate of NPK compost with addition of eggshell and without addition of eggshell. This research was designed by pre test - post test to organic garbage like rest of vegetable, rest of foliage, and remains of fruits, ox dirt and eggshell. Data analyzed descriptively by comparing rate of NPK result of pengomposan with rate of NPK optimal compost. The result described the quality of compost with addition of eggshell got by percentage of Nitrogen rate 0, 6755, Phosphorus 49, 553%, and Calcium 0,767%. Percentage of compost with addition of ox dirt of N = 0, 7835 %, p = 0, 48706 %, K = 0, 88 % compost with addition of eggshell and ox dirt of N 0, 904%, P = 51, 682 %, K = 0, 941 result of analysis indicate that compost with addition of eggshell and higher ox dirt of percentage of rate of NPK its compared to addition of ox dirt and of eggshell. Organic garbage (rest of vegetable, rest of foliage, and remains of fruits) more efficient and be a benefit to human being and environment hence the organic garbage can be exploited standard upon which in making of compost. To quicken process of compost and improve the quality of compost can be used by eggshell. Keywords:      composting process, organic garbage

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