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Yogyakarta, Indonesia

Khairudin M.,State University of Yogyakarta
ICITACEE 2015 - 2nd International Conference on Information Technology, Computer, and Electrical Engineering: Green Technology Strengthening in Information Technology, Electrical and Computer Engineering Implementation, Proceedings | Year: 2016

This study describes the development of robust control design for a spindle of lathe machine. The dynamic of the spindle is uncertain and time variation due to the deepness variation on cutting process. The dynamics model of a spindle were obtained by system identification. To find a linear model of the system based on the nonlinear system using the data of real time system identification. For obtaining a controller synthesis used linear models and its uncertainty bound with real time system identification. Using the selected input signal, the data of output and responses are acquired and then a nonlinear system identification is performed to obtain a linear model. Practical design steps are presented in which compensator and prefilter-based conditions are formulated to obtain a robust control of a spindle. Moreover, effects of the deepness variation on cutting process and the dynamic characteristics of a spindle are studied and discussed. © 2015 IEEE.

The use of information technology to support the business organization's performance is one thing that needs to be done by large-scale industrial sector and small industrial sector (SMEs) to face global competition. As a developing country, the SMES sector in Indonesia is still not fully adopt and utilize information technology (IT) in the business process. Factors of contributors, inhibitors and the effect of the competitive environment and government support will tend to trigger SMEs to adopt IT. This study tries to explore the influence Contributor, Inhibitor, Government Support, and Competitor Pressure, to Technology Readiness (H1, H2, H3, H4), and the Influence of Technology Readiness on Behavioral to Use (H5). The study used 446 valid sample of SMEs of craft industry and being tested using the Partial Least Square (PLS) technique. The testing result shows that the Contributor and Inhibitor have the significant effect on the Technology Readiness with p-value of.000 (<0.05) (H1 and H2 were supported). The testing result of the Technology Readiness on the Behavior to Use also shows the significant result with the p-value 0.00 (<0.05) (H5 was supported). The test of the effect of the Government Support and Competitor Pressure shows the insignificant result with the p-value of 0.81 and 0.53 (>0.05) (H3 and H4 were not supported). Further analysis also found that the Government Support and Competitor Pressure do not affect on the IT users (Behavior to Use) in SMEs. The finding also strengthen the previous claim that the Government Support and the Competitor pressure are not the component which make SMEs ready to adopt and use the IT on their business process. © 2015 The Authors.

Nayono S.E.,State University of Yogyakarta | Nayono S.E.,Karlsruhe Institute of Technology | Winter J.,Karlsruhe Institute of Technology | Gallert C.,Karlsruhe Institute of Technology
Waste Management | Year: 2010

A highly polluted liquid (" press water" ) was obtained from the pressing facility for the organic fraction of municipal solid waste in a composting plant. Methane productivity of the squeezed-off leachate was investigated in batch assays. To assess the technical feasibility of " press water" as a substrate for anaerobic digestion, a laboratory-scale glass column reactor was operated semi-continuously at 37 °C. A high methane productivity of 270m-3 CH4ton-1 CODadded or 490m-3 CH4ton-1 VSadded was achieved in the batch experiment. The semi-continuously run laboratory-scale reactor was initially operated at an organic loading rate of 10.7kg CODm-3d-1. The loading was increased to finally 27.7kg CODm-3d-1, corresponding to a reduction of the hydraulic retention time from initially 20 to finally 7.7days. During the digestion, a stable elimination of organic material (measured as COD elimination) of approximately 60% was achieved. Linearly with the increment of the OLR, the volumetric methane production of the reactor increased from 2.6m3mreactor-3d-1 to 7.1 m3mreactor-3d-1. The results indicated that " press water" from the organic fraction of municipal solid waste was a suitable substrate for anaerobic digestion which gave a high biogas yield even at very high loading rates. © 2009 Elsevier Ltd.

Sugiman,State University of Yogyakarta
Jurnal Teknologi (Sciences and Engineering) | Year: 2013

Student as a mathematics teacher candidate must have competence in solving and creating mathematical problems. This paper describes how the two competencies are mastered by students. On the one competence, problem solving ability is reviewed by using four aspects: (1) conceptual and procedural understanding, (2) strategy knowledge, (3) mathematical communication ability and (4) accuracy. On the other competence, student's creativity in developing mathematical problem is evaluated based on: (1) fluency, (2) flexibility and (3) novelty. Research subjects are students who take Integral Calculus course in the academic year of 2012. Data are collected through documentation, observation and interview and then analyzed quantitatively and qualitatively. Students show their abilities and some difficulties in both solving and creating mathematical problem. © 2013 Penerbit UTM Press. All rights reserved.

Ariswan,State University of Yogyakarta
Advanced Materials Research | Year: 2014

CdTe polycrystalline thin films had been fabricated using vacuum evaporation technique. Their properties had been investigated using X-ray diffraction, energy dispersive spectroscopy (EDS), scanning electron microscope (SEM) and uv-vis spectroscopy. The results showed that the CdTe thin films crystalized at hexagonal structure with lattice parameters a = 6.45 Å and c =7.66 Å. The EDS results showed that the chemical composition was non stoichiometry, slightly rich of Tellerium with Cd/Te of 0.9. It had a uniform shape with color homogenity and an optical band gap at room temperature about 1.47eV. © (2014) Trans Tech Publications, Switzerland.

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