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Angkasa: Jurnal Ilmiah Bidang Teknologi
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Articles 91 Documents
DAMPAK PEMBERIAN IMPULS ARUS TERHADAP TINGKAT PERLINDUNGAN ARRESTER TEGANGAN RENDAH Widyastuti, Diah Suwarti; Sugiarto, Sugiarto
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 7, No 2 (2015): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Arrester is a device used to protect equipment and electrical systems against overvoltage that one reason is the surge of lightning. Because lightning is a natural phenomenon that the process can not be predicted about time and magnitude of the impulse currents, and if arrester hit by lightning impulse with high peak current value and than arrester is feared can not operate as it should. This research use three impulse current peak value there are 533.33A (0.03 pu), 3866.6A (0.3 pu) and 6858.7A (0.5 pu) tested at low voltage arresters. The test results shown the highest value of leakage current arrester at a maximum voltage of operation (Uc) after buffeted by the current impulse has a value of leakage current 0,32 mA, 0,33 mA and 0,33 mA respectively, still below 1 mA (corresponding international standard IEC 61643-1 Edition 2.0 03/2005). Based on the value of leakage current, it can be said that the arresters in good condition and have not changed the characteristics of volt-ampere (current leaking still relatively the same) and still have good insulating properties even after the current impulse overwritten. The highest value of residual voltage arresters at the peak impulse voltage 10 kV, 15 kV, 20 kV and 24 kV, is 1124 Volt meaning that the margin has exceeded the limit of endurance voltage VW1 class (1000 Volts) amounted to 112.4%, and not exceed the VW2 (2000 Volt) amounted to 43.5%, according to ISO standard 04-7021.21-2004, arresters can be used to protect the electrical equipment with voltage endurance on VW2 class.
VARIASI SUDUT PANCAR BURNER CUP UNTUK MENINGKATKAN PERFORMA PEMBAKARAN PADA KOMPOR BERBAHAN BAKAR BIOGAS MENUJU DESA MANDIRI ENERGI DI YOGYAKARTA Hariyanto, Kris; Mardwianta, Benedictus
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 8, No 2 (2016): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Biogas is an alternative energy sources as a substitute for fossil fuels in household activities daily, but there are obstacles in the use of biogas, namely the difficulty of arranging a flame that is stable and fuel consumption relatively less efficient biogas. So it takes a design development system that will produce a burning stove produces biogas-fueled stove fits the purpose of research, on the other hand biogas stove should be simple, cheap production price, maximum efficiency and safe to use. Stages in the study include: desk assessment, creation of objective requirements design, manufacture conceptual and basic design, manufacture real stove. As for knowing the performance of the stove carried stove performance tests are: test flame stability and efficiency. The results showed that the efficiency of the biogas stove design results in only 31 percent higher than the efficiency of biogas stoves old design, while the fuel consumption of biogas stoves new design is 16 percent lower when compared with fuel consumption of biogas stoves old design. In terms of manufacture and ease of repair and maintenance of gas cookers new design is more easily repaired and easy to make and simple in form compared with the old design biogas stoves.
PENGARUH SUHU PREHEAT DAN VARIASI ARUS PADA HASIL LAS TIG ALUMINIUM PADUAN TERHADAP KEKUATAN TARIK DAN KEKERASAN Ahmadi, Nurfi
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 8, No 1 (2016): Mei
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Aluminium has a good nature; corrosion-resistant, lightweight, and able to be recycled. But the connection with welding aluminum is difficult to do so we need the right way this study aims to determine the characteristics of the results of weld aluminum with large variations in preheat temperature and current. Aluminum Alloy AA 3003 TIG welded with Filler ER 5356, a variation current 110 A, 130 A, 140 A and preheat temperature of 75 degree celcius, 125 degree celcius, 175 degree celcius, then welds tested tensile, hardness, and microstructure. The results showed that the variation o f the current 110 A with a preheat temperature of 175 degree C has the highest tensile strength and hardness.
ANALISIS KUALITAS PERBAIKAN CITRA MENGGUNAKAN METODE MEDIAN FILTER DENGAN PENYELEKSIAN NILAI PIXEL Sajati, Haruno
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 10, No 1 (2018): Mei
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Metode Median Filter adalah salah satu metode perbaikan kualitas citra pada domain spatial. Domain spatial memiliki kelebihan pada hasil perbaikan karena perbaikan citra dilakukan per-pixel. Karena perbaikan citra dilakukan terhadap pixel, metode Median Filter memiliki komputasi yang tinggi dan waktu eksekusi yang lama.Dengan melakukan penyeleksian terhadap pixel yang perlu diperbaiki dapat mengurangi waktu proses perbaikan dan meningkatkan kualitas citra karena pixel yang sudah benar, tidak perlu diperbaiki. Pengukuran kualitas citra dilakukan menggunakan Peak Signal to Noise Ratio (PSNR) dengan membandingkan nilai citra asli dengan citra hasil perbaikan. Nilai PSNR ideal untuk disebut sebagai citra yang baik adalah 30dB.Kualitas Citra metode Median Filter dengan penyeleksian memiliki kenaikan nilai PSNR sebesar 5.6% dan memiliki kenaikan kecepatan waktu proses perbaikan kualitas citra sebesar 8.3% dibanding merubah semua nilai pixel citra
ANALISIS PENINGKATAN KAPASITAS SISTEM SELULER 4G LTE PADA SISTEM KOMUNIKASI HIGH ALTITUDE PLATFORM STATION Waluyo, Catur Budi; Astuti, Yenni
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 9, No 1 (2017): Mei
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

In the development o f wireless communications, to provide high-speed data services and wide bandwidth become a challenge. One technique to make it happen is by using Multicarrier Orthogonal Frequency Division Multiplexing (OFDM) modulation, where in OFDM, frequency selective fading channel effect will be perceived flat fading by each subcarrier. One communication system that supports OFDM technology is Long Term Evolution (LTE) with various types of bandwidth configurations provided. To improve LTE performance in capacity building, coverage area and data rate, it can use multi antenna technique both in receiver and sender, and integrate with High altitude platform station (HAPs) system. In this study the estimation used is Linear Minimum Mean Square (LMMSE). The relationship o f the elevation angle and the K factor is directly proportional, but the elevation angle value is inversely proportional to the diameter o f the HAPs coverage area. In addition, the more the number o f used antennas, the greater the capacity served. Based on the simulation results, the system with estimation can be used to expand the coverage area to 215.77 km which is from 0.032 km in QPSK modulation, speed 60 kmpj with 2x2 antennas.
VIRTUAL PANORAMA LANDING DAN TAKE OFF BANDARA ADI SUMARMO SOLO Retnowati, Nurcahyani Dewi; Muttaqim, Muhammad Zainal
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 8, No 1 (2016): Mei
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

The development of information technology and lead to intense competition in all areas, many parties began implementing a strategy to improve services. Information obtained from various sources such as the Internet can make it easier to determine the state o f a place or vehicle that will be addressed, but a lot of information from various sources, it only displays a static image that is not enough to describe the situation as a whole as well as the environment, it is necessary for the proper media fo r representing the information. One type of appropriate multimedia effective dam to provide information or a description of the location of these is to use virtual panoramic view. Not like a video that is merely one direction (forward grooved) virtual panoramic view is designed to allow the user to interact directly with the environment to crawl closer and more interactive. Final results from this aplication is a multimedia display that can be applied in any kind o f media because using ActionScript for basic program so that it can be applied via online websites or interactive CDs or display advertising.
Pengembangan Sistem Downlink Data Adaptif Untuk Peningkatan Daya Jelajah Pesawat Tanpa Awak Basukesti, Agus; Adiputra, Bangga Dirgantara
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 9, No 2 (2017): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

The main challenge for the development of unmanned aircraft today is the cruising range of unmanned aircraft. One of the causes of limited cruising range is the weakness of the communication system between aircraft and ground station. In this study designed a system of data downlink integrated with adaptive control so that it can increase cruising range from unmanned aircraft. The method used in this research is the experimental method to get the design and pilot plan downlink data system combined with adaptive control to create intelligent data downlink device that can increase cruising range unmanned aircraft. From this research found that Kalman Filter is the best algorithm used in designing an adaptive downlink system.
KORELASI NILAI KOEFISIEN ARAH SERAT BETON TERHADAP KEKUATAN TARIK LENTUR PADA BETON DENGAN SERUTAN BAJA MAUPUN HAREX SF Zulaicha, Lilis; Marwanto, Marwanto
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 7, No 2 (2015): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Concrete has high compressive strength that is capable of supporting a large and heavy structures. But concrete has a low tension strength and brittle nature (Brittle). The weakness of this concrete properties can be improved by providing treatment such as provide fiber. There are several fibers that can be used to improve the properties of concrete and one of them is the steel fibers. Steel fibers possess the strength and modulus of elasticity which is relatively high. Moreover steel fibers do not change the shape of the influence of alkali in the cement. Imposition in a long period o f time does not affect the mechanical properties of steel fiber. Bond in the composition of the mixture can be increased because fastening mechanically. The study used the steel shavings and fiber materials Harex SF. The aim of this examination was intended to determine the coefficient of concrete fiber orientation at the same time the value of flexural tension strength of concrete produced in the concrete mix wearing Harex SF fiber or steel shavings. Steel fiber used in this study using the percentage of 1 until 4 percent of the weight of the concrete mix and perform quality control for the split tension strength of concrete at 28 days. From this research, the percentage of 3 percent as the optimum value based on the ease of doing the concrete (workability) used for research flexural tension strength of concrete and fiber orientation coefficient of concrete in the concrete with steel shavings and concrete with fibers Harex SF. From the testing that has been done shows: flexural tension strength fiber-reinforced concrete Harex SF 3 percent of 5,037 MPa and flexural tension strength of concrete with steel shavings of 11,035 MPa and the coefficient offiber direction concrete well with fiber Harex SF and shavings o f steel both are between 0 and 1 (0 less than or equal to eta of phi less than or equal to 1) with an average value close to 0, which means both fibers are working properly so that is proven to increase the tension strength offlexural concrete.
ANALISIS KONEKTIVITAS JARINGAN TRANSPORTASI UDARA NASIONAL Gunawan, Gunawan; Medianto, Rully
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 8, No 2 (2016): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

The airport as flight network node is the starting point and the end of the movement of people/goods. The airport can also be a transit point before continuing the journey to the destination. The closure of the airport due to force majeure such as a disaster or terrorism may disrupt the national air transportation network. The effects of the closure of an airport to the national air transportation network depends on the level of connectivity of the airport. This study aimed to quantify the connectivity between two airports in the national air transportation network. Based on the connectivity data, it can be determined that appropriate mitigation strategies during an airport closure due to force majeure.
PENGARUH RAPAT ARUS ANODIZING TERHADAP NILAI KEKERASAN PADA PLAT ALUMINIUM PADUAN AA SERI 2024-T3 Nugroho, Fajar
Angkasa: Jurnal Ilmiah Bidang Teknologi Vol 7, No 2 (2015): November
Publisher : Sekolah Tinggi Teknologi Adisutjipto

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Abstract

Aluminum alloy AA 2024-T3 is widely applied in the aircraft industry because it has good mechanical properties such as; light weight, good conductivity and the corrosion resistance. However Aluminium 2024-T3 susceptible to wearing. One method to improve the wear resistance o f AA 2024-T3 is the anodizing process. The aims of this research to study the effect of current density and anodizing time against the hardness of aluminum alloy AA 2024-T3. The process of anodizing was carried out using 10 percent sulfuric acid solution with the current density of 1.5 Ampere per decimeters square, 3.0 Ampere per decimeters square and 4.5 Ampere per decimeters square with immersion times of 30, 40, 50 and 60 minutes. Furthermore, the surface hardness was measured by using the Vickers hardness test method. As the supporting data the composition of the test conducted, testing the microstructure, and vickers hardness test. This study shows that the surface hardness of aluminum alloy AA 2024-T3 is influenced by the current density and anodizing time with varying values. Its shows that higher current density o f the anodizing caused optimal time tends to be short. The longer anodising time it will produce greater layer of aluminum oxide.

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