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Jurnal Sains Dasar

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Published by Universitas Negeri Yogyakarta

ISSN : 20859872 EISSN : 24431273 DOI : 10.21831

Core Subject : Education,

Education

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Articles 14 Documents

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Search results for , issue "Vol 4, No 2 (2015): October 2015" : 14 Documents clear

MATHEMATIC MODEL FOR SITY BUS SCHEDULING IN YOGYAKARTA Sahid Sahid; Fitriana Yuli S; Dwi Lestari
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Various methods can be used to construct a mathematical model of the transportation problems. One model that can be used is a linear model. Several studies have used a linear model to get the schedule and the optimal route of bus trips. This research will build a mathematical model of a city bus transportation problems in DIY using linear models. Linear model is built to get the condition density city bus passengers on shifts respectively that morning, noon, and evening. After finding a suitable model, applied to the bus passengers data in Yogyakarta. From these results it can be seen the optimum conditions in terms of density, because the condition of the city bus at this time that quiet enthusiasts. Besides, the optimum density at each shift in the morning is 11 passengers, 10 passengers during the day, and evening 9 passengers. Keywords: transportation problems, the linear model, the optimal route, density

RECOVERY OF GOLD (Au) AND SILVER (Ag) METALS IN THE ELECTRONIC WASTE THROUGH MULTILEVEL PRECIPITATION PROCESS Siti Marwati; Regina Tutik Padmaningrum; Sunarto Sunarto
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This research aims to determine the percent recovery of gold (Au) and silver (Ag) in the electronic waste such as CD-RW and determine the purity of gold and silver metals in the electronic waste such as CD-RW that through multilevel precipitation process. The first step was the optimization of the concentration of thiourea and time dissolution of gold and silver in the sample. The concentration of thiourea and the time dissolution optimum obtained from conentration of gold and silver maximum. By The percent recovery of gold and silver are determined by comparing the concentration of gold and silver between in the solution sample and in the sample without dissolution that be analyzed by XRF. The scond step was the multilevel precipitation process and calcination. Precipitation and calcination of the filtrat was dissolution results in the optimum condition. Reagent used was a solution of hydrochloric acid and potassium carbonate. The precipitation gold and silver produced from the precipitation of dissolution again and then be analyzed by atomic absorption spectrophotometry. The purity was determined by comparing the weight of gold and silver between in the precipitate and in the solution. The results of this research showed that the percent recovery of the silver in the CD-RW through the process dissolution with thiourea 10 g/L and 4 hours soaking time were 21.09 %. The purity silver preipitate were 0.15 %. The percent recovery and the purity of gold can not be determined because the gold contained in the sample were not detected or below the limit of detection equipment. Keywords: recovery, gold, silver, electronic waste

ANALYSIS OF RELATION TERM BETWEEN CUMMULATIVE PERFORMANCE INDEX AND SNMPTN DATA BASE USING APPRIORITY ALGORITHM Kuswari Hernawati; Nur Insani; Bambang Sumarno; Nurhadi Waryanto
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

In the university management, in addition to resources infrastructure, facilities and people, information systems is one of the resources that can be utilized to enhance the competitive advantage and provide accurate data for the benefit of policy makers, for example, information about the test scores SNMPTN, region of origin students, GPA student, students study duration. Yogyakarta State University to accept new students with an average of approximately 6,000 people annually, through the National Selection of State Universities Student (SNMPTN), SBMPTN (Joint Student Selection State University) and the Independent Selection exam (SM). With the increasing number of prospective students through SBMPTN, then increasingly also the basic data in a database of prospective students annually. By utilizing basic data on SBMPTN students and grade point average (GPA), the study aims to apply data mining techniques using the association rule Apriori algorithm to look for patterns of association between baseline SBMPTN and UNY students GPA. Basic data to be processed SBMPTN mining student data origin include school, home school district data, earnings data parent, parental education level data, the average value data UAN, and data values academic potential test (TPA). The results obtained are no data in the data base SNMPTN that significantly affect the acquisition of GPA. This is evident from the association rules derived from the 50 best asosoasi rules not seen the emergence of itemset GPA accompanied by the emergence of other itemset. Keywords: Data Mining, Association Rule, Algoritma Apriori, SNMPTN

FACTORS INFLUENCING JOB FATIGUE AND STRESS AMONG EMPLOYEES OF YOGYAKARTA STATE UNIVERSITY ION COLUMN TECHNIC WITH LOCAL ZEOLITE AND ACTIVE CARBON Siti Mariyam; Kartika Ratna Pertiwi
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Stress and fatigue related to workplace may interrupt with the effectivity and productivity workers, including the employees who work in the office. This research aims to determine the level of stress and fatigue related to workplace and to describe determinant factors invloved in job stress and musculosceletal fatigue. It is designed as an analytical survey, designed as cross sectional approach. Population were the employees of Yogyakarta State University, samples were taken with purposive sampling technique. The respondents were they who fulfilled the inclusion criteria. Job stress and fatigue were taken with observation and structured intervie, using adapted instrument from Berutu Soetopo (2010) and Andininsari (2009). Musculosceletal fatigue were measured with nordic body map method. Other paramater included anthropometry and ergonometry measurement and individual characteristics. The finding shows that most respondents (95%) suffered mild job stress and more than half of respondents (73%) had mild musculosceletal fatigue. About 60% of workplace facilities were not suitable according to ergonomic requirement. Determinant factors for job stress such as age, employment status and workplace ergonometry, while determinant factors for musculosceletal fatigue includes age body mass index and also ergonometry. Keywords: workplace, stress, fatigue, musculosceletal

THE STRUCTURE AND CHEMICAL COMPOSITION OF SEMICONDUCTOR MATERIAL Sn(Se0,2S0.8) THIN FILM PREPARED USING EVAPORATION METHOD FOR SOLAR CELL APPLICATION Joko Utomo Utomo; Ariswan Ariswan
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This research aims to grow a thin film Sn(Se0.2S0.8) by evaporation method. The researcher can understand the effect of spacer variations towards the crystal structure, lattice parameter, surface morphology, and chemical composition of Sn(Se0,2S0,8) thin film. The process of Sn(Se0.2S0.8) thin film preparation was done by using the evaporation method with pressure about 2 x 10-5 mbar. The process of Sn(Se0.2S0.8) thin film deposition was performed by giving some space between the substrate and the source i.e. 25 cm, 15 cm, and 10 cm. Characterization process was performed by using X-ray Diffraction (XRD) to determine the structure and parameter of thin film, Scanning Electron Microscopy (SEM) to determine the thin film of surface morphology, and Energy Dispersive Analysis X-Ray (EDAX) to determine the chemical composition of the thin film. The result of XRD characterization show that the Sn(Se0.2S0.8) thin film was polycrystalline and it has an orthorombic crystal structure, with the lattice parameter were sample 1 (spacer 25 cm): a = 4.306 Å, b = 11.30 Å, c = 4.139 Å; sample 2 (spacer 15 cm): a = 4.286 Å, b = 11.18 Å, c = 4.123 Å; sample 3 (spacer 10 cm): a = 4.301 Å, b = 11.30 Å, c = 4.143 Å. The result of SEM characterization in the sample 2 of Sn(Se0.2S0.8) showed that the surface morphology of the sample consisted of homogeneous oval shaped grains, with the diameter size of crystal grains on the surface about 0.3 μm – 0.5 μm. The result of EDAX analysis showed that comparison of percentage of chemical composition thin film Sn(Se0.2S0.8) was 1 : 0.11 : 0.79. Keywords: evaporation method, semiconductor Sn(Se0.2S0.8), solar cell, material characteristics

SILICA PURIFICATION FORM MERAPI VOLCANO SAND AS PHOTOVOLTAIC RAW MATERIALS Sulistiyani Sulistiyani; Erfan Priyambodo; Larasti Yogantari
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Purification of silica sand volcanic Mount Merapi has been done, for raw material photovoltaic. Leaching purification process is done using aqua regia solution, H2SO4, and HCl. Purification of silica sand of Mount Merapi as a raw material photovoltaic assumes that photovoltaic technologies that utilize solar energy is quite affordable, do not run out, and clean so that it will provide long term benefits are substantial. Stage purification process through grinding up to size 60 mesh, iron using magnetic separation, leaching of acid and alkaline leaching. Characterization of the samples using XRD and XRF. The result showed that Mount Merapi volcanic sand containing silica is high at 48-50%. XRD characterization results indicate that the silica in sand samples well as silicon dioxide or mineral has amorphous structure. Among aqua regia, H2SO4 and HCl leaching that has the ability to nicest namely the concentration of concentrated HCl and purified silica has a purity of 59%. Keywords: purification, silica, volcano sand

DISTRIBUTION OF PARASTATISTICS FUNCTIONS: AN OVERVIEW OF THERMODYNAMICS PROPERTIES R. Yosi Aprian Sari; W. S. B. Dwandaru
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This study aims to determine the thermodynamic properties of the parastatistics system of order two. The thermodynamic properties to be searched include the Grand Canonical Partition Function (GCPF) Z, and the average number of particles N. These parastatistics systems is in a more general form compared to quantum statistical distribution that has been known previously, i.e.: the Fermi-Dirac (FD) and Bose-Einstein (BE). Starting from the recursion relation of grand canonical partition function for parastatistics system of order two that has been known, recuresion linkages for some simple thermodynamic functions for parastatistics system of order two are derived. The recursion linkages are then used to calculate the thermodynamic functions of the model system of identical particles with limited energy levels which is similar to the harmonic oscillator. From these results we concluded that from the Grand Canonical Partition Function (GCPF), Z, the thermodynamics properties of parastatistics system of order two (paraboson and parafermion) can be derived and have similar shape with parastatistics system of order one (Boson and Fermion). The similarity of the graph shows similar thermodynamic properties. Keywords: parastatistics, thermodynamic properties

OPTIMATION OF ANTIMICROBIAL SUBSTANCE PRODUCTION IN CELL FREE EXTRACT FROM THERMOPHYLIC BACTERIA FERMENTATION AFTER MERAPI ERRUPTION Evy Yulianti; Anna Rakhmawati; Kartika Ratna Pertiwi
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

The aims of this study was to investigate the effect of medium with different pH (6,7,9), salt concentration (0,5; 1; 2 %) and fermentation periode (24 and 48 hr) to the antimicrobial activity of cell free extract to three pathogens, Eschericia coli, Staphylococcus aureus, and Candida albican. This study consists of antimicrobial compounds production with different medium and continued by antimicrobial tested to fungi and bacterial pathogens Eschericia coli, Staphylococcus aureus, and Candida albican by Kirby Bauer method with paper disk. Different salt concentration, pH and fermentation periode affected the antimicrobial activity potency of cell free extract yielded by thermophylic bacteria. Treatment which yielded CFE with the best antimicrobial activity was treatment with 24 hr fermentation, pH 7 and salt concentration 2% to S aureus and pH 6 salt concentration 1% to E coli. Cell free extract had no potency as antifungi to Candida albicans except CFE yielded by thermophylic bacteria fermented in medium with pH 7 and salt concentration 1% in 24 hr with inhibition zone index 1,17. Keywords: cell free extract, antimicrobial, pH, salt concentration, fermentation period

SYNTHESIS OF AMYL VANILLIL ETHER AS WARMING AGENT FROM VANILLIN Budimarwanti, C.; Theresih, Karim
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Synthesis of amyl vanillyl ether from vanillin was carried out by two different methods, two-steps reaction method and one-step reaction method. In two-steps reaction method beginning with the first stage reduction of vanillin with NaBH4 to obtain vanillyl alcohol. Then, dehydration vanillyl alcohol and amyl alcohol with concentrated sulfuric acid. Synthesized compound were identification by TLC, IR spectroscopy and GCMS. In one step reaction method the vanillyl alcohol as a result of reduction of vanillin with NaBH4 are not isolated in advance, immediately reacted with amyl alcohol to form amyl vanillyl ether compound with concentrated HCl dehydrator. The results of two-steps reaction method showed that the reduction reaction of vanillin with NaBH4 produced vanillyl alcohol. Vanillyl alcohol compound that produced is white powder and yield 41.28%. Vanillyl amyl ether compound could not synthesis by dehydration from vanillyll alcohol from reduction of vanillin and amyl alcohol. Ether compound from dehydration of vanillyl alcohol from reduction of vanillin and amyl alcohol is diamyl ethers. Method one reaction step successfully synthesized amyl vanilil ether compound. Amyl vanilil ether compound that produced is liquid, colorless and yield 86.42%. Keywords: amyl vanillil ether, vanillin, vanillil alcohol, amyl alcohol

SYNTHESIS OF BIODIESEL FROM KAPUK SEED OIL (Ceiba Pentandra L) AT VARIATION STIRRING DURATION IN TRANSESTERIFICATION PROCESS Siswani, Endang Dwi; Kristianingrum, Susila; Tohari, Tohari
Jurnal Sains Dasar Vol 4, No 2 (2015): October 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

The synthesis of biodiesel targeted as SNI 04-7182-2006 standard has been done from kapuk randu seed, following two steps i.e. sokhlet extraction process of kapuk seed oil from kapuk seed using n-heksane as a solvent, and the production of biodiesel from kapuk seed oil by transesterification process using methanol and KOH as catalyst. Transesterificatin process was performed at temperature 50 oC with the variation of stirring duration as followed 50, 75, 100 and 125 minutes. The kapuk randu extraction resulted % kapuk randu seed oil, while the transestherification process resulted around 55 - 65%. The biodiesel product characteristics provided the density value of all biodiesel at stirring durations variation are suitable with SNI standard (850 – 890 kg/m3), the viscosity value of all biodiesel are higher than the range SNI value (2,3 – 6,0 cSt). While the flash point values are lesser than SNI standard (10160 - 11000 cal/g). Keywords: kapuk randu seed, transestherification, biodiesel

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