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GEMA TEKNOLOGI

gema_teknologi
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Published by Universitas Diponegoro

ISSN : 08520232 EISSN : 2656582X DOI : -

Core Subject : Science,

Computer Science & IT

Gema Teknologi Journal (pISSN : 0852-0232, eISSN : 2656-582X) is an open access journal published by Vocational School, Diponegoro University, Indonesia. Gema Teknologi publishes articles from various engineering disciplines (the results of original scientific research or new scientific studies of literature). Editor receives articles both in English and Indonesian. Gema Teknologi Journal is published 2 (two) times a year, on April and October.

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Articles 166 Documents

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PENGARUH CACAT LAS PADA SAMBUNGAN PIPA BAWAH LAUT (GIRTH WELD) DENGAN MENGAPLIKASIKAN FAILURE ANALYSIS DIAGRAM (FAD) Suyadi, Suyadi
Gema Teknologi Vol 16, No 1 (2010): April 2010 - October 2010
Publisher : Vocational School Diponegoro University

Suyadi, An under sea pipe connection (girth weld) is an area that possibly will get defect. This weld defects have a potential for causing tension concentration, so that there will be preliminary crack. This crack will spread due to cyclic loads received by the structure. This final assignment research is performed for evaluating mechanical integrity and girth weld having weld defect using method of Failure Analysis Diagram (FAD) and it takes a sample of case for South Sumatra West Java pipe belongs to PGN Co.Ltd. FAD is a method, which is good enough for evaluating the integrity of pipe structure having crack like flaw upon the weld. FAD divides two areas, namely safe area and unsafe area constructed by two axis, namely x axis that is stress ratio (Lr) and y axis that is stress intensity ratio (Kr). Stress ratio (Lr) is a ratio between a ref and a yield, mean while stress intensity ratio (Kr) is a ratio (stress intensity factor) between Kl and KIC (fracture toughness material). ANSYS 8.0 software is used for modeling by considering that the defect is in the form of semi elliptic with a/2c variation, that is 0,0469; 0,0938; 0,01406; and 0,1750. The loading upon the pipe is considered as the minimum loading (ï³pull = 8284.25 psi), medium (ï³pull = 41421.25 psi) and maximum (ï³pull = 82842.5 psi). From the analysis result, it is obtained that crack dimension with a/2c 0.175 is not safe upon minimum and medium loading, mean while upon the maximum loading condition, all modeled cracks dimensions cause the pipe is not safe. Keywords : pipeline, girth weld, semi elliptical defect, FAD.

PENENTUAN FAKTOR BERPENGARUH PADA EKSTRAKSI RIMPANG JAHE MENGGUNAKAN EXTRAKTOR BERPENGADUK Anggista, Giovani; Pangestu, Ilyas Teguh; Handayani, Dwi; Yulianto, M. Endy; Astuti, Septi Kusuma
Gema Teknologi Vol 20, No 3 (2019): April 2019 - October 2019
Publisher : Vocational School Diponegoro University

Giovani Anggista , Ilyas Teguh Pangestu, Dwi Handayani, M. Endy Yulianto, Septi Kusuma, in this paper explain that the main part of ginger used is rhizome. Processed ginger products that can be developed are ginger oleoresin which contains components of gingerol, shogaol, zingerone, resin and essential oils. Ginger oleoresin content ranges from 3.2 - 9.5%, while the content of gingerol in oleoresin is between 14-25% and shogaol between oleoresin. 2.8-7.0%. Considering the benefits of high-antioxidant ginger which functions as an anti-inflammatory and prevents tumor growth, it is necessary to extract the ginger rhizome. The purpose of this study was to determine the factors that most influence the extraction of gingerol from the ginger rhizome using a stirred extractor and relatively good conditions. Experiments were carried out with various solvents, pH and temperature. Solvents 4 liters and 8 liters, pH 4 and 6 and temperatures 60oC and 100oC. The Gingerol content is measured by a VIS spectrophotometer. The most influential factor in extraction of ginger was determined by experimental design 23. The analysis of the results showed that for extracting 500 grams of powdered ginger using water as a solvent, the most influential factor was pH, in this case, at pH 6 containing 4% ginger.

RANCANG BANGUN ANTENNA WAJANBOLIC DENGAN DIAMETER 46 CENTIMETER PADA FREKUENSI 1900 MHz UNTUK MEMPERKUAT PENERIMAAN SINYAL WCDMA Nafik, Ichsyan; Yuniarto, Yuniarto
Gema Teknologi Vol 17, No 1 (2012): April 2012 - October 2012
Publisher : Vocational School Diponegoro University

Ichsyan Nafik, Yuniarto, in paper a 1900 MHz, 46 cm wajanbolic antenna design to strengthen wcdma signal reception explain that the antenna is a device used to transmit or receive electromagnetic waves electromagnetic waves. Reception using an antenna will amplify the signal acquisition in accordance with the ability of the antenna itself. Signal instability that often occurs in WCDMA networks makes the need for strengthening the acquisition of the signal is very large. Antenna Wajanbolic is one option reinforcement signal acquisition. In WCDMA networks, downlink frequency used at 2100 MHz, while the uplink frequency to 1900MHz. Antenna wajanbolic Must ditune to resonate in the uplink frequency is 1900 MHz. The final project focuses on making wajanbolic antenna for Line of Sight (LoS) who works at a frequency of 1900 MHz for WCDMA (3G). In accordance with the name wajanbolic antenna, this antenna uses a reflector from the pan, with a waveguide of modified pipes are coated with aluminum duct tape, and a signal receiver using a USB 3G modem. From the results of the testing and analysis of the results showed that wajanbolic antenna is directional antenna that has the directivity signal. This wajanbolic got an antenna gain of 16 dB value. Keyword: wajanbolic antenna, WCDMA, Line of Sight (LOS)

PERENCANAAN FILTER PASIF UNTUK MENINGKATKAN KUALITAS DAYA LISTRIK DI KAMPUS DIPLOMA III FAKULTAS TEKNIK UNDIP Subari, Arkhan; Manan, Saiful
Gema Teknologi Vol 17, No 4 (2014): October 2013 - April 2014
Publisher : Vocational School Diponegoro University

Arkhan Subari, Saiful Manan, in this paper explain that most electronic equipment is non-linear load. Likewise with the equipment in campus buildings Diploma III Faculty of Engineering. Non-linear load is a load that has a voltage waveform supplied from non sinusiodal although sinusoidal voltage. Non-sinusoidal wave causes the shape of the voltage becomes distorted or defects that result in decreased quality of power. The defect wave called harmonics. To dampen harmonics on non-linear load can be used filter. With the addition of a filter on the power system, then the waves of unwanted harmonics can be suppressed as small as possible. In addition, harmonic filter at the fundamental frequency can compensate for reactive power and is used to improve the power factor of the system. From the measurement results in the Diploma Program Campus FT Undip found that the influence of harmonic waves big enough. THDv reached 32.13% while the THDi amounted to 7.85%. It affects so cos phi cos phi measured just 0.72. After the installation of a passive filter, the value THDv and THDi be good lebik ie 1.61% and 0.39% to reach 0.94 cos phi measured. Key word: non-linear loads, non-sinusoidal waveform, harmonics, power factor, filter LC

RANCANG BANGUN ALAT PENGATURAN ARAH PUTAR MOTOR DC POWER WINDOWS BERBASIS PLC PANASONIC MENGGUNAKAN HUMAN MACHINE INTERFACE (HMI) Alfitri, Tafki Aunika Fariz; Setiono, Iman
Gema Teknologi Vol 19, No 2 (2017): October 2016 - April 2017
Publisher : Vocational School Diponegoro University

Tafki Aunika Fariz Alfitri, Iman Setiono, in this paper explain that at this time human life has become more advanced especially in the field of science and technology, all people compete to create technology that is useful and easy for humans. At present the equipment in general has used a remote monitoring and operation system. This system usually uses a microcontroller or PLC as a control. In an effort to facilitate human work, in this case I tried to make a design setting the direction of rotation of the DC power windows. This DC power windows motor is usually used in the car to move the windshield up and down. This Windows power DC motor uses a power supply of 12 volt DC and the output is between 0-5 Volt. This design uses Panasonic PLC as its main control. By using the relay as a reverse rotation setting and forward DC power windows, the motor will automatically move in reverse and forward. The input of a 24 Volt DC panasonic PLC originating from the adapter. The design of this tool can later be applied to a glass in the car by using the Panasonic PLC as its control and other component components needed in the design of the rotary direction arrangement. In the operation by way of toch screen using a human machine interface as a contruction tool to drive the DC power window to spin in reverse or forward.

RECYCLING OF PINEAPPLE WASTE USING LACTOBACILLUS DELBROECKII TO LACTIC ACID Moch Busairi, Abdullah
Gema Teknologi Vol 16, No 1 (2010): April 2010 - October 2010
Publisher : Vocational School Diponegoro University

Abdullah, in paper recycling of pineapple waste using lactobacillus delbroeckii to lactic acid, explain that The pineapple wastes juice contains mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for organic acid fermentation. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were carried out in shake flask fermentation using Lactobacillus delbrueckii. Effect of some parameters such as temperature, initial pH, initial substrate concentration, yeast extract concentration and fermentation time to the yield have been studied. The highest yield was 85.65 % achieved at 40 o C, pH 6.00, 52.5 g/l sugar concentration with 5 g/l yeast extract. There was no significant increasing in lactic acid production was observed if supplementation of yeast extract above 10 %..

DESAIN SISTEM KENDALI UMPAN BALIK STATE PADA KASUS KONTINYU UNTUK MEJA KERJA CNC Mangkusasmito, Fakhruddin; Nugroho, Tsani Hendro
Gema Teknologi Vol 20, No 2 (2019): October 2018 - April 2019
Publisher : Vocational School Diponegoro University

Fakhruddin Mangkusasmito, Tsani Hendro Nugroho in this paper explain that One of the important control system in the manufacturing industry is the position control. Mainly in the Computer Numerical Control (CNC) machine, work-table motion control system is used to regulate work-table movements when the machine process a workpieces on it. On standard machines, work-table movements are two axes (X-Y), which is driven by a motor and lead-screw. The discussion in this research only focus on one axis assuming that the systems on both axes are the same and independent. In this research, MATLAB is used to describe the behaviour of the system and also to design appropriate control system in continuos system using state feedback linear controller such as pole placement , tracking system, full order compensator and reduced order compensator. The goal is to obtain a fast response with a rapid rise time and settling time to a step command, while not exceeding an overshoot of 5%. The specification are than a percent overshoot equal to1%, 0,05s settling time and 0,03s rise time. The performance of each control methods are simulated and analyzed to decide the best suit control method for the systems with such criteria. And the result verify that using tracking system controller method achieve such specification with 0% overshoot, 0,04s settling time and 0,028s rise time.

OPTIMALISASI PENGUKURAN ARUS OLEH CURRENT TRANSFORMER UNTUK MEMINIMALISIR SUSUT ENERGI PADA PABRIK BAJA PT. INTI GENERAL YAJA STEEL DAERAH SEMARANG BARAT Amalia, Devita; Ariyanto, Eko
Gema Teknologi Vol 18, No 1 (2014): April 2014 - October 2014
Publisher : Vocational School Diponegoro University

kWhmeter adalah suatu alat ukur energi listrik yang mengukur secara langsung hasil kali tegangan, arus, faktor kerja, dan waktu yang bekerja selama jangka waktu tertentu. Pengukuran energi yang dominan adalah pengukuran arus, di mana arus yang diukur melebihi arus yang terdapat di kWh meter. Untuk itu dibutuhkan suatu peralatan instrumen yang dapat menurunkan arus yaitu trafo arus. Susut distribusi pada sistem kelistrikan dapat terjadi pada alat pengukur dan pembatas (APP) yang dipergunakan dalam transaksi tenaga listrik dengan pelanggan. Susut yang terjadi pada APP ditentukan oleh akurasi APP dan akurasi pembacaan atau pengambilan data hasil pengukuran. Untuk menghindari atau mengurangi susut tersebut pemilihan trafo arus yang tepat sangat dibutuhkan seperti mengamati seberapa besar ketelitian trafo arus dalam pengukuran. Kelas ketelitian trafo arus, burden, kesalahan sudut, dan juga arus nominal dari sisi primer trafo arus harus diperhatikan. Jika pemilihan tidak sesuai, maka akan memungkinkan terjadinya susut.

DESKRIPSI TEKNIS PENGENDALI TEMPERATUR INDUSTRI SEBAGAI BAGIAN DARI SISTEM REGULASI TEMPERATUR Tadeus, Dista Yoel; Setiono, Iman
Gema Teknologi Vol 20, No 1 (2018): April 2018 - October 2018
Publisher : Vocational School Diponegoro University

Dista Yoel Tadeus, Iman Setiono, in this paper explain that temperature regulation is one of the most important needs for the industry. Lots of processes and production are carried out under certain temperature conditions and free from interference. Industrial temperature controller is one of the basic equipment to meet these needs. On the market there are various types, specifications, and brands of temperature controllers, but have similarities with one another mainly lies in the basic functions of temperature regulation capabilities. This article describes the background of industrial temperature controllers principal, also covers control concepts, basic controller configurations, control methods, actuator equipment support, and examples of sensor parameter settings and controls on the Autonics TC4S series temperature controllers.

ALAT UKUR TDS (TOTAL DISSOLVED SOLID) AIR GARAM DENGAN RESISTIF SEBAGAI INDIKATOR Dewa, Aloisius Wisnu Lalita; Sasmoko, Priyo
Gema Teknologi Vol 19, No 1 (2016): April 2016 - October 2016
Publisher : Vocational School Diponegoro University

Aloisius Wisnu Lalita Dewa, Priyo Sasmoko Â in this paper explain that, physical water quality can be identified in various ways, one of which is measuring the amount of solute called Total Dissolved Solid (TDS). This study aims to design and make a TDS solution by using two electrodes as sensors. These two electrodes flow alternating current and negative values alternately into water. Analog signal in the form of voltage is read by the microcontroller by converting it into a digital signal, then the microcontroller processes the data and displays the TDS value. Tests are carried out by measuring the same solution using TDS meters and salt water TDS. Testing starts from a solution of 175 ppm to 8500 ppm. Making solutions based on TDS meter factory production. The results of salt water TDS measurements showed that the measured tds values increased from 173 ppm to 8007 ppm. Error reading at 8500 ppm, this is because the reading distance of salt water TDS is only up to 8260 ppm.Â Keywords : TDS, conductivity, electroda, measurement device.ReferencesMalvino. 1995. Prinsip-prinsip Elektronkai. Jakarta : Erlangga.Rusmadi, Dedy. 2001. Mengenal Komponen Elektronika. Bandung : Pionir JayaSumariyah, Yulianto. T, Priyono J, 2006. Rancang Bangun Sistem Pengukur Konduktivitas Larutan Elektrolit Menggunakan Mikrokontoler AT89C51. Program Studi Fisika Fakultas MIPA Universitas Diponegoro. Semarang.Utomo, D. 2012. Alat pengukur resistansi konduktivitas. dan Total dissolved solids air dengan Teknik dorong-tarik. Program Studi Sistem Komputer. Fakultas Teknik Elektronika dan Komputer. Universitas Kristen Satya Wacana. Salatiga.Wiono.A,Rahmawati. E, 2014.Â Perancangan Dan Pembuatan Alat Ukur Konduktivitas Larutan Berbasis Mikrokontroler. Program Studi Fisika Fakultas MIPA Universitas Negeri Surabaya. Surabaya

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