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Semesta Teknika
Published by Universitas Muhammadiyah Yogyakarta
ISSN : 1411061X     EISSN : 25025481     DOI : https://doi.org/10.18196/st
Core Subject : Engineering,
Engineering
SEMESTA TEKNIKA is a reputable refereed journal devoted to the publication and dissemination of basic and applied research in engineering. SEMESTA TEKNIKA is a forum for publishing high quality papers and references in engineering science and technology. The Journal is published by the Faculty of Engineering, Universitas Muhammadiyah Yogyakarta, INDONESIA. Copyright is by the publisher and the authors. The Journal is issued in electronic form and also issued in printed form as annual volume for the contributors only. The journal contains original research papers, review articles, short notes and letters to the editors. The topics of interest include modeling, experimental, analytical and numerical investigations on the mechanical, physical, chemical and mineralogical properties of material, developing the prototype/instrument, technology and construction process. Topic of management in industry and civil construction is also considered. SEMESTA TEKNIKA receives manuscripts from the contributor written in the Indonesian and English. Manuscripts submitted to the journal for publication must not have been previously published or is under consideration simultaneously by any other publication. Manuscripts submitted to SEMESTA TEKNIKA will be reviewed Peer Reviewers local and foreign.
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Articles 715 Documents
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Pengaruh Campuran Abu Sekam Padi terhadap Kuat Tekan Paving Block Budi Waluyo; As'at Pujianto; Bagus Soebandono
Semesta Teknika Vol 16, No 2 (2013): NOVEMBER 2013
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v16i2.4899

Abstract

Rice husk is an abundant by-product of rice milling results, and so far only used as a fuel for combustion red stones, burning for cooking or thrown away. Rice husk ash (RHA) is a waste material of rice that has special properties. This material also contains chemical compounds that can be pozzolan, which contains silica (SiO2), a compound which, when mixed with cement and water can be used to enhance the compressive strength and tensile strength of concrete while silica is a chemical compound that is dominant in the rice husk ash. This study aimed to compare the results of the average compressive strength of the normal paving block with the added ingredient of rice husk ash, assess the effect of the addition of rice husk ash to the compressive strength and prices comparison between the paving block and normal paving block with the added ingredient of rice husk ash. In this study, rice husk ash serves as a replacement for cement additives with a variation of 0%, 30%, 35% and 40% by weight of cement in comparison 1pc: 10ps, 1pc: 13ps and 1pc: 15ps. The results showed that the paving blocks with a mixture of rice husk ash in comparison 1pc: 10ps produce optimum compressive strength with a mixture of rice husk ash 16.6% in the amount of 32.709 MPa. Furthermore in comparison 1pc: 13ps, paving block compressive strength values obtained with the optimal mix of rice husk ash rice 13.0% amounting to 23.709 MPa. Finally, in comparison 1pc: 15ps, paving block compressive strength values obtained with the optimal mix of rice husk ash 15.0% amounting to 17.260 MPa.
Simulasi Cell Breathing CDMA 2000 1x Menggunakan DELPHI Alfin Hikmaturokhman; Hesti Susilawati; Ilham Perdana
Semesta Teknika Vol 10, No 1 (2007): MEI 2007
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v10i1.852

Abstract

Cell breathing is variation of CDMA cell size depends upon the amount of traffic occurs within the cell. This work assume that the cell is in the ideal condition based on  the following assumptions,  each cell is completely isolated from the other cells, with the result that no intercell interference and signals from MS cause no interference within the cell. It makes no intracell interference occurs within the cell. In an ideal condition where is none of interference occurs, cell size and amount of users in a cell depend on several factors such as bitrate, required signal strength that MS must deliver to BS, voice activity factor, power control accuracy factor and Eb/It of the system. The result obtained by change the values of the parameters and based on the result obtained, the impact of the parameter to the cell size and amount of user in a cell could be recognized.
Optimalisasi Energi Terbarukan pada Pembangkit Tenaga Listrik dalam Menghadapi Desa Mandiri Energi di Margajaya Arif Febriansyah Juwito , Sasongko Pramonohadi , T. Haryono
Semesta Teknika Vol 15, No 1 (2012): MEI 2012
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v15i1.440

Abstract

The Energy Self-Sufficient Village is one of main programs from goverment about the village ability to produce energy. This program has been launched in 2007 by the President of the Republic of Indonesia, to enhance energy security in rural areas by harnessing local energy potential. The criteria of Energy Self-Sufficient Village is village capability to produce at least 60% of the total amount of required energy, using renewable energy. Geographically, Margajaya village has solar and microhydro resource which is very potential for being developed. Furthermore, Margajaya also produces agricultural commodities such as palm oil, in which it also produces waste like palm bunches which is a very potential biomass. The optimization of renewable energy for electrical power generation which has annual power peak of 65kW and daily energy consumtion of 415kWh/day in Margajaya village has been designed using HOMER. The result from simulation of Hybrid renewable system in HOMER showed that Hydro, Biomass and grid is the most economical solution over hydro-biomass-PV with battery, to design hybrid system with minimum total net present cost (NPC) and cost of electricity. The system can serve annual 100% of load in Margajaya and have surplus of electricity, and could sell to grid with amount of 124.827kWh/years. Economically, the electricity of the system costs US$ 0,013/kWh.
Pemeriksaan Material pada Pembangunan Rumah Non-Engineered di Daerah Rawan Gempa Dusun Serut, Palbapang Kabupaten Bantul, Yogyakarta Muhammad Heri Zulfiar
Semesta Teknika Vol 21, No 2 (2018): NOVEMBER 2018
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.212224

Abstract

Bantul Regency is a region with high level of seismic activity in Indonesia. Buildings that have the highest risk of collapse to earthquake are non-engineered buildings or residential buildings built without planning or not according regulation. This study aims to know contruction practices and material examination on non-engineered buildings in earthquake prone areas in accordance with the Indonesian National Standard. The object research is the construction of non-engineered building in Serut Village, Palbapang, Bantul Regency. The testing of material construction materials include: concrete test, reinforcing steel test and bricks test. the material are tested on the laboratory of Universitas Muhammadiyah Yogyakarta.  The observations and measurements to the practices of construction consist of: concrete sloof with size 15 × 20 cm with the main reinforcement 4Ø12 and beugel reinforcement Ø6-150; column with size 10 × 15 cm with main reinforcement 4Ø10 and beugel reinforcement Ø6-150; the concrete mixture is made manually with a composition 1 cement: 3 sand: 2 gravel; Brick size 4.35 cm x 12.036 cm x 23.902 cm class criteria M-6 module. Laboratory material test results showed: steel reinforcement diameter Ø 10 mm obtained tensile strength (fy) 401.52 Mpa; Ø12 mm diameter obtained tensile strength (fy) 393,736 M.Pa; concrete have average compressive strength of 181 kg/cm2; brick test have average compressive strength of 20.03 kg/cm2. The conclusion of contruction practices on non-engineered buildings in earthquake prone areas are adequate on major earthquake, the quality of construction concrete and reinforcing steel are fulfilling the criteria and requirements of the Indonesian National Standard, but quality of material brick is not adequate standar. 
Penelitian Nilai Kalor Biomassa : Perbandingan Antara Hasil Pengujian Dengan Hasil Perhitungan Wahyudi Wahyudi
Semesta Teknika Vol 9, No 2 (2006): NOVEMBER 2006
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v9i2.875

Abstract

Indonesia memiliki berbagai jenis bahan bakar biomassa yang banyak seperti limbah pertanian, limbah peternakan dan lainnya. Walaupun banyak digunakan oleh masyarakat pedesaan sebagai bahan bakar, namun pemanfaatannya belum optimal, bahan bakar limbah pertanian masih berkisar pada kayu dan sekam padi, sedangkan ampas tebu, daun kering dan limbah peternakan belum banyak digunakan. Banyakya jenis biomassa yang belum dimanfaatkan secara optimal, khususnya di Indonesia, mengharuskan adanya penelitian-penelitian yang ditujukan untuk pemanfaatan biomassa sebagai bahan bakar. Pada penelitian ini akan dilakukan pengujian nilai kalor biomassa meliputi limbah pertanian dan limbah peternakan. Tujuan penelitian ini adalah untuk mengetahui nilai kalor biomassa yang diuji dan membandingkannya dengan hasil perhitungan menggunakan korelasi-korelasi yang ada. Penelitian diawali dengan melakukan analisa ultimat dan analisa proksimat masing-masing bahan untuk mengetahui komposisi dasar bahan. Data tersebut digunakan untuk memperkirakan nilai kalor bahan bakar berdasar korelasi-korelasi yang ada. Pengujian menggunakan kalorimeter bomb memberikan data kenaikan suhu yang digunakan untuk menghitung nilai kalor. Nilai kalor hasil pengujian dibandingkan dengan nilai kalor yang dihitung dari korelasi, sehingga dapat diketahui korelasi yang paling sesuai untuk biomassa yang diuji.   Hasil pengujian menunjukkan nilai kalor biomassa yang diuji adalah 10,2 MJ/kg sampai dengan 24,7 MJ/kg. Korelasi yang memberikan nilai kalor mendekati nilai kalor hasil pengujian adalah Korelasi Tillman. Korelasi yang paling sesuai untuk biomassa yang diuji adalah HHV = 1.3941.C-18.3638.H+1.4682.O+16.7184.N-95.753.S+0.5184.A
Perbaikan Balok Beton Bertulang dengan Metode Jacketing dengan Bahan Ferosemen Akibat Beban Siklik pada Beban Ultimit Bagus Soebandono , Andreas Triwiyono, Muslikh
Semesta Teknika Vol 14, No 2 (2011): NOVEMBER 2011
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v14i2.546

Abstract

A large number of buildings construction was made of reinforced concrete structure, composed of concrete and steel. The reinforced concrete structure elements could experience damage due to earthquake, from light to heavy failure, such as heavy bending-shear crack near the beam column joint. It is necessary, therefore, to repair the structure adopted good method and workability. The specimens were part of exterior beam-column joint model. Cyclic lateral load was applied to simulate earthquake load. This research used 3 specimens: US-1, the shear damage specimen as the result of first-step loaded test, then are repaired by using 1 layer rectangular galvanized welded wire mesh became R-US.1. US-2, the shear damage specimen as the result of first-step loaded test, then are repaired by using 2 layers rectangular galvanized welded wire mesh became R-US.2. UBB, the bending damage specimen as the result of first-step loaded test, then are repaired by using 2 layers rectangular galvanized welded wire mesh became R-UBB.   The result showed that the retrofitted on ultimate load by using jacketing ferrocement increased the ultimate strength capacity of 91,667%(US-1 to R-US.1), 81,818%(US-2 to R.US.2) and 28,571%(UBB to R-UBB) respectively. Increasing the hysteretic energy were 215, 66%(US-1 to R-US.1), 273,11%(US-2 to R.US-2) and 389, 84%(UBB to R-UBB). The ductility of retrofitted specimen 6,64(R-US.1) and 12,72(R-US.2). The initial stiffness of retrofitted specimens decreased 60%(US-1 to R-US.1), 40%(US-2 to R-US.2) and 18%(UBB to R-UBB).
Alat Perangkap Tikus Elektronis Alfi Arianto; Fathul Qodir A
Semesta Teknika Vol 8, No 2 (2005): NOVEMBER 2005
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v8i2.907

Abstract

Alat perangkap atau jebakan biasanya digunakan oleh seseorang yang ingin menangkap hewan buruannya. Alat perangkap yang umum digunakan disekitar rumah adalah alat perangkap tikus. Tikus merupakan salah satu hewan liar yang sering berkeliaran disekitar rumah. Selain sering memakan bahan makanan yang berada di rumah, kotoran-kotoran dari tikus ini juga dapat mendatangkan berbagai penyakit. Masalah akan muncul ketika menangkap tikus menggunakan sangkar perangkap yang sudah ada yaitu jumlah tikus yang mampu ditampung dalam satu sangkar perangkap hanya satu ekor tikus saja. Perancangan alat perangkap tikus elektronis ini terdiri dari dua bagian yaitu bagian rangkaian elektronika dan bagian mekanik, dengan persyaratan dapat mendeteksi tikus yang masuk ke dalam perangkap, mempunyai sangkar pengumpul, dapat menggiring tikus ke sangkar pengumpul, dan dapat memberi informasi adanya tikus yang tertangkap. Hasinya adalah alat dapat bekerja dengan spesifikasi mempunyai rangkaian sensor inframerah, rangkaian relai pengatur pintu perangkap, rangkaian timer 10 detik dan 15 detik, dan rangkaian power supply 12 volt dan 9 volt.
Analisis Cacat Las Incomplete Fusion Dan Retak Memanjang Pada Waterwall Tube Boiler PLTU Paiton Unit 1 Sahlan Sahlan
Semesta Teknika Vol 18, No 1 (2015): MEI 2015
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v18i1.701

Abstract

Weld defects in the form of "incomplete fusion" and lengthwise (longitudinal) crackswas observed at the boiler tube welding of steam power plants of Paiton Unit 1, row 3, located860 mm above theheader, .Incomplete fusionmay be caused by incorrect use of the the magnitude of current,welding speed, or manipulation or selection of the electrode being used, thatmay lead tounevenfusityand affect generate the cracks along the incomplete fusion region. Incomplete fusion defects in the waterwall tubes welding being visible from the edge of the boundary between the base material and weld region with the presence of indentation or depression in the form of a very deep crater welding. Indentations or hollows, that will be observed more clearly by using an optical microscope with a magnification 1000X, which in the presence of imperfections observed molecular fusion between grain boundaries and inter-molecular crystal. At 1000X magnification ofthe HAZ (heat affected zone) region,transition structure forming brittle fractures was observed 
Analisis Kinerja Ruas Jalan HOS Cokroaminoto Akibat Perkembangan Lalu Lintas di Yogyakarta Reza Gustav
Semesta Teknika Vol 15, No 2 (2012): NOVEMBER 2012
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v15i2.1360

Abstract

Yogyakarta is a region with high traffic. It also has high population density. These matters have been predicted to cause transportation problems. HOS Cokroaminoto Street, as a road in urban city center, has the potential to have such problems. Analysis and evaluation needs to be done to maintain good performance of the road. Manual Kapasitas Jalan Indonesia 1997 is used to measure the performance of traffic which includes operational analysis and the planning of urban roads. Level of Service Criteria (LSC) is determined based on the regulation of The Ministry of Transportation KM No. 14 of 2006. Traffic data had been obtained by counting the number of vehicles for 3 days on the busy-hour. These data were presented in tabular data of the vehicle, and then the performance of the traffic was analyzed. For urban roads, form UR-1, UR-2, and UR-3 (MKJI 1997) are used. Based on the results of the performance analysis on HOS Cokroaminoto Street with MKJI 1997 method, in 2010, the degree of saturation (DS) of the road is 0.43. It means that, in LSC term, this road is in level B. It is predicted that, in 2016-2020, this road will not satisfy the eligibility standard (DS 0.75). This shows that the performance improvement of HOS Cokroaminoto Street is required. From the alternative solutions, the scenario of side friction reduction is more rational to maintain the eligibility and performance of HOS Cokroaminoto Street.
Beton Mutu Tinggi dengan Bahan Tambah Superplastisizer dan Fly Ash As’at Pujianto
Semesta Teknika Vol 13, No 2 (2010): NOVEMBER 2010
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jst.v13i2.718

Abstract

Increasing concrete strength is one of the main necessities of concrete technology. For more than the last 20 years, high strength concretes with compressive strength ranging from 50 MPa up to 140 MPa have been used worldwide in high rise buildings and bridges with long spans, or buildings in aggressive environments. But in Indonesia high strength concretes possesses maximum compressive strength of 60 MPa. The properties of concrete are affected by cementitious matrix, aggregate, and the transition zone between these two phases. Reducing the water-cement ratio and the addition of pozzolanic admixtures like fly-ash are often used to modify the microstructure of the matrix and to optimise the transition zone. The reduction of the water-cement ratio results in a decrease in porosity and refinement of capillary pores in matrix, but flowing ability of the concrete will also decrease so that it can’t be workable. Then it workablity can be improve by the use of a superplastisizer. The method used refers to the planning of normal concrete, which is contained in the SKSNI 03-2834-1992. The results showed that superplastisizer with doses of more than 2% of the cement paste does not increase the strength of concrete. For all the rest of the experiments, the superplastisizer dosage was determined about 2 % of the powder mass. The first tests showed a good workability of the fresh concrete and a good self compacting ability with the fly-ash dosage of 12 % of the powder mass. The interest in reducing costs for increasing the concrete strength, can be successfully achieved in this research.

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