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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 237 Documents

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THE EFFECT OF NONLINEAR DAMPING TO A DYNAMICAL SYSTEM WITH CENTER PHASE PORTRAIT Kus Prihantoso Krisnawan; Husna Arifah
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/jsd.v4i1.8439

This paper discusses the effect of nonlinear damping to a 2-dimesional system that has center phase portrait. The phase portraits of the damped system are drawn for 3 different values of parameter. These phase portraits stand as the numerical proof of phase portrait change. To prove the change analiticaly, we use the theorem that guarantee the existence of periodic solution. The result shows that nonlinear damping changes the phase portrait topologically. It means that the system undergoes a generalized Hopf bifurcation. Keywords: generalized Hopf bifurcation, center phase portrait, periodic solution

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

SIMULATION ANALYSIS OF THE TOTALLY ASYMETRIC SIMPLE EXCLUSION PROCESS TO DETERMINE THE PROFIL OF THE ONE-BODY CORRELATION FUNCTION, TWO-BODY CORRELATION FUNCTION, AND THREE-BODY CORRELATION FUNCTION AROUND THE ENDS OF THE LATTICE WITH LATTICE NUMBER VARIATION R. A. Adipurno; Wipsar Sunu Brams Dwandaru; Denny Darmawan; Bambang Ruwanto
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This study aimed to determine the behavior of one-body, two-body, and three-body correlation functions of the model dynamics TASEP with sequential updating rules and open boundary conditions on vehicular traffic around the end of the traffic light. The study began with the determination of algorithm to model the dynamics of TASEP and coding, with the variation of the input rate (α) , the output rate (β), and the number of lattice sites (N). Then the program run with specific time limit (t) and number of systems (M). The value of the one-body correlation function determines the average occupancy of particles in lattice site-i at time t. Two-body correlation function determines the average occupancy of particle at site-i when there is another particle occupying the nearest neighbor lattice, i+1, at time t. Three-body correlation function determines the average occupancy of particles to occupy lattice site-i when there are other particles occupying the nearest and next nearest neighbor lattice sites, i+1 and i+2, at time t. The value of the one-body correlation function turns out to be larger than the value of the two-body correlation function. The value of the two-body correlation function is larger than the value of the three-body correlation function for all phases. The correlation between a vehicle to another vehicle will be even greater. Keywords: TASEP, sequential updating, n-body correlation function

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

THE OPTIMATION OF CELLULASE ENZYME OF MOLD ISOLATED FROM AGRICULTURE LAND IN WUKIRSARI AFTER MERAPI ERUPTION Umniyatie, Siti; Rakhmawati, Anna; Yulianti, Evy
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

The aim of this study was to develop potency of mold isolated from agriculture land after Merapi eruption in 2010 at Wukirsari, Cangkringan, Sleman, Yogyakaerta. The treatment were temperature and pH optimation to the cellulase enzyme activity and the protein level yield by mold isolate A 2.10, A 2.15 and B 3.18 in different substrate, avicel and carboxymethyl cellulose (CMC). This study was experimental study to find out the substrate, pH and temperature which yield the best activity and protein level from mold isolate A 2.10, A 2.15 dan B 3.18. the population of this study all of the crude enzymes from mold isolate, and the sample was 1 ml of crude enzyme which treated with different substrate, pH and temperature. The result of this study showed that the best susbtrate was avicel and the optimum temeperature and pH for isolate A.2.10 was 25 ⁰C Keywords: optimation, cellulase enzyme, cellulolytic

SPECIES INVENTORY OF AMPHIBIOUS FISH IN INTERTIDAL ZONE OF NGRENEHAN, NGOBARAN AND NGUYAHAN COASTELS, GUNUNG KIDUL, YOGYAKARTA Sukiya, Sukiya; Putri, Rizka Apriyani
Jurnal Sains Dasar Vol 4, No 2 (2015): Jurnal Sains Dasar
Publisher : Yogyakarta State University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Tropical region is high on faunal diversity including vertebrates and invertebrates. Research on diversity of amphibious fish in Intertidal zone ofÂ Yogyakarta southern coast is still limited so there is no complete records regarding these unique fish. This research aimed to know the diversity of amphibious fish in three beaches of Yogyakarta southern coast, namely pantai Ngrenehan, Ngobaran dan Nguyahan. Fish sampling were conducted using random sampling method combined with observational method. Fish were collected using small nets then identified to species rank. The total length of each fish were measured and recorded. Few individuals of the same species were sacrificed as voucher specimens. The result showed that in pantai Ngrenehan, Ngobaran, and Nguyahan, five different species of amphibius fish were found, which are Cabillus lacertops, Bathygobius fuscus, Enneapterygus sp., Blenniella cyanostigma, and Blenniella caudolineata. Cabillus lacertops was found in all of sampling locations. Enneapterygus sp. was found in pantai Nguyahan while Bathigobius fuscus, and Blenniella caudolineata can only be found in pantai Ngrenehan. Further studies regarding the adaptation, ecological features, taxonomy and biological reproduction of Yogyakarta southern coastâsÂ amphibious fish are still needed.Â Keywords: Inventarization, amphbious fish, intertidal zone, Yogyakarta southern coast

VISCOSITY TEST OF VEHICLE ENGINE OILS Prasetyowati, Rita
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This study aims to determine the value of the kinematic viscosity lubricants motorcycle that has been used at various temperatures and the use of distance. This study also aims to remedy mengtahui how the value of the kinematic viscosity of the lubricant car that has been used in a wide range of temperature variation and distance usage. Viscosity liquid, in this case is the lubricants, can be determined using the Redwood viscometer By using Redwood viscometer, can be measured flow time required by 50 ml of the sample at a constant temperature. Time measurement result is known as the Redwood's sec or conventional viscosity. Conventional viscosity can be determined from the kinematic viscosity values. For motorcycle lubricant viscosity measured at a temperature of 30ͦ C, 50ͦ C, 65ͦ C and 100ͦ C, with the use of distance variation 0 Km, 5 Km, 10 Km, 15 Km and 20 Km. For car lubricant viscosity measured at a temperature of 30ͦ C, 50ͦ C, 65ͦ C and 100ͦ C, with variations in the use of distance 0 km, 1000 km, 5000 km, and 10000 Km. Motorcycle lubricant viscosity values at a temperature of 100ͦ C is 9.54 m2 / s (new lubricant), 1.15 m2 / s (use 5 Km), 5.86 m2 / s (use of 10 Km), 8.02 m2 / s (use of 15 Km), and 9.11 m2 / s (use of 20 Km). Lubricant viscosity values at a temperature of 1000C car is 6.73 m 2 / s (new lubricant), 7.89 m2 / s (use 1,000 km), 6.0 m2 / s (use 5000 Km), and 7.55 m2 / s (use 10000 Km). Keywords: viscosity, oil, temperature

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

THERMODINAMIC PARAMETERS ON THE SORPTION OF PHOSPHATE IONS BY MONTMORILLONITE Jaslin, Ikhsan; Endang, Wijayanti; Sunarto, Sunarto
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

The sorption of phosphate by montmorillonite at 10, 30, and 50 oC were investigated aiming to mainly determine thermodynamic parameters for the formation of surface complexes in the adsorption of phosphate ions by montmorillonite. Data were collected by adsorption edge experiments investigating the effect of pH, adsorption isotherms enabling the effect of sorbate concentration, and acid-base titration calculating protons released or taken up by adsorption process. Data analysis was carried out using surface complexation model to fit the data collected in this study using the parameters obtained from previous study, as well as to calculate the values of ΔH and ΔS. Previous study reported that phosphate ions formed two outer-sphere surface complexes with active sites of montmorillonite through hydrogen bonding. In the first complex, [(XH)0– H2L─]─, the phosphate was held to permanent-charge X─ sites on the tetrahedral siloxane faces, and the second complex, [[(SO─)(SOH)]– – [H2L]─] 2─ was formed through the interaction between the phosphate and variable charge surface hydroxyl groups at the edges of montmorillonite crystals and on the octahedral alumina faces. The values of ΔH for the first and second reactions are 39.756 and 3.765x10-7 kJ mol‒1 respectively. Since both reactions have positive enthalpy values, it can be concluded that the reactions are endothermic. Large energy for the first reaction is needed by X─ sites (permanent negatively charge sites of montmorillonite) to be partially desolvated, on which K+ or other surface cations are replaced by H+ ions in the surface protonated process, and are then ready to interact phosphate ions in the solution. Small values of ΔH for the second reactions indicates that hydrogen bonds formed by phosphate and SOH sites in the second reaction are easily broken out, and the phosphate can easily desorbed from the surface. The values of ΔS for the first and second reactions are 122.523 and 2.393 x10-2 J K‒1 mol‒1, which are greater than -10 kJ mol‒1 and indicates that the surface reactions occurs through dissociative mechanisms.Keywords: montmorillonite, adsorption edge, extended constant capacitance, surface complexation model, enthalpy, reaction mechanisms

SEPARATION OF Ca AND Fe METAL ION IN SOURCE WATER BY ADSORPTION COLUMN TECHNIC WITH LOCAL ZEOLITE AND ACTIVE CARBON Suyanta Suyanta; Hanafi Idham Kholid; Bambang S
Jurnal Sains Dasar Vol 4, No 1 (2015): April 2015
Publisher : Faculty of Mathematics and Natural Science, Universitas Negeri Yogyakarta

This research aims are to separate of Ca and Fe metal ion in source water, with local zeolite and active carbon by adsorption column technic. Efficiency of separation are control by adsorption time and size of zeolite. Method that used was column adsorption with a flow system in which sample is applied to the filtration tube containing zeolite and active carbon. Initial and final concentrations of the samples were analyzed using Atomic Adsorption Spectrophotometer instrument. The results obtained shows that ability adsorption of zeolite to Ca and Fe metal ion are a good. Zeolite 1 (10 mesh) can reduce iron concentration until 93.98 % and zeolite 2 (5mesh) until 98.88% for 1 – 4 week range time. Whereas reducing of calcium concentration is not good, until 2 week period time adsorption of calcium ion is about 50%. Keywords: adsorption, zeolite, source water

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