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All Journal Jurnal Bisnis dan Ekonomi Majalah Ilmiah Teknologi Elektro ENVIAGRO Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains JIKSI (Jurnal Ilmu Komputer dan Sistem Informasi) JURNAL BISNIS & AKUNTANSI UNSURYA Idea : Jurnal Studi Jepang
Yohanes Yohanes
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Arts Humanities Computer Science & IT Economics, Econometrics & Finance Education Electrical & Electronics Engineering Engineering Environmental Science Languange, Linguistic, Communication & Media Mathematics Social Sciences Other

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Analisis Vegetasi di Lahan Bekas Penambangan Timah Desa Rebo, Kabupaten Bangka Lestari, Tri; Abdi, Zainal; Widodo, Joko; Yohanes, Yohanes
ENVIAGRO Vol 2, No 2 (2008): ENVIAGRO, VOLUME 2, OKTOBER 2008
Publisher : Universitas Bangka Belitung

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Abstract

The Vegetation Analize of Ex-Tin Mining Land  in Rebo Village, Bangka This research was conducted by observing a number of interconnected ecological variables with spreading of vegetations on ex-tin mining land, located in Rebo Village, Bangka Regency from May to july 2008.   Vegetation analysis can be utilized to determine types of dominant and pioneer plant  spesies being able to grow in  ex-tin mining land for revegetation.  This analysis indicates that the following pioneer or dominant plant spesies common in the studued are of ex-tin mining land, these are among mengkirai (Commersonia sp), mentenuk (Trema orientalis L), kedebik (Melastoma malabathricum L) and leban (Vitex pinnata L).  These plant spesies were the common one whitin the category of seedling, sapling, pole and tree respectively.  Keywords :Ex-tin mining land,  Revegetation of pioneer plant.
ANALISIS PERBEDAAN KINERJA SAHAM JANGKA PENDEK DAN JANGKA PANJANG PADA PERUSAHAAN YANG MELAKUKAN INITIAL PUBLIC OFFRERING (IPO) DI PASAR MODAL INDONESIA Mg. Kentris Indarti; Kartika Andi; Yohanes Yohanes
Jurnal Bisnis dan Ekonomi Vol 11 No 1 (2004): Vol. 11 No. 1 EDISI Maret 2004
Publisher : Fakultas Ekonomika dan Bisnis, Universitas Stikubank

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Abstract

The objective of this study is to find empirical evidence about presupposition that underpricing and underperformance phenimenons occurs on companies issued Initial Public Offering (IPO) in Indonesia. There are 36 companies that issued IPO during 1998-2000. After choosing then with purposive sampling method, there are 33 companies to be analyzed in this study. Results from one sample t-test show that in the short run, there are large positive mean excess return. This result is consistent with prior studies in numerous countries. In the long run, the perfomance is underperformed. Result from paired sample t-test show that there is a significant defference between short and long run stock performance in companies issued IPO.Key words: Initial Public Offering, Performance, Underpricing, Underperfomed
Pengaruh Putaran Benda Kerja Dan Tool Feeding Terhadap Kekasaran Permukaan Dengan Menggunakan Metode Pemakanan Orthogonal Pada Proses Turn-Milling Evon Yulianto; Yohanes Yohanes
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 5, No 1 (2018): Wisuda April Tahun 2018
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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The turn-milling test has three methods in the process of working are orthogonal, tangential, and co-axial. In this methods turn-milling test produces a varied surface roughness. To optimize the surface roughness in this method orthogonal turn-milling then the variation of testing is done at the rotation velocity of workpiece and feeding velocity. The testing process of turn-milling machining is performed on conventional lathe with the addition of a rotary tool. The purpose of this research is to get the optimum rotation velocity of workpiece and feeding velocity of the value of surface roughness and To know the effect of velocity rotation of workpiece and feeding velocity to surface roughness value. With increasing velocity rotation of workpiece and feeding velocity, velocity rotation of the workpiece increased will affect the surface roughness value. Based on the roughness class N, the 630 rpm rotation of workpiece parameters with feed rate of 0.060 mm is a good parameter in this study because it produces a roughness value of 1.489 μm lower than the other test.Keywords : Turn-milling, Round, Feeding, Roughness.
Uji Nilai Kalor Oli Bekas Sepeda Motor Sebagai Bahan Bakar Mesin Diesel Dongfeng R175 Arief Rachman Widyanto; Aryo Sasmita; Yohanes Yohanes
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 8 (2021): Edisi 1 Januari s/d Juni 2021
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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The production laboratory of the Department of Mechanical Engineering Riau University, has modified the diesel engine used as a used oil fueled generator, the problem is that the emission feasibility test has not been carried out. The purpose of this study was to determine the calorific value of used motorcycle oil and compare it with dexlite and to measure this calorific value using a bomb calorimeter. Keywords: Calorific value, Diesel engine, Used motorcycle oil, Fuel.
Studi Eksperimental Pengelasan Baja Karbon Rendah Menggunakan Pengelasan Smaw Sistem Sliding Adaptive Two Axis Dengan Variasi Sudut Elektroda Uberkis Uberkis; Yohanes Yohanes
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 6 (2019): Edisi 1 Januari s/d Juni 2019
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Abstract

SMAW welding (shield metal arc welding) has advantages in the current and welding angle that can be varied, and the penetration width of the electrode melting can be adjusted. This study uses a SMAW welding machine with a sliding adaptive two axis system design so that the electrode angle in the welding process is constant, this design is the development of a vertical sliding adaptive system. This study varied the angle of the electrode to find out the results welding from the SMAW welding machine with the sliding adaptive two axis system. In this study the characteristics of welds are based on visual observations and mechanical properties using a tensile test. The parameters varied were the electrode angles 45°, 70°, and 90°. the welding speed controlled by Arduino Uno. The material used was low carbon steel, using campuh V with a slope angle of 60°. In this study the metal splicing area that had the highest tensile strength was 533.44 MPa and the lowest value was 399.88 MPa with 9 specimens varied. The micro-welding structure is determined by many factors including heat input, current strength, welding speed, and cooling rate. In this study the HAZ region has a larger grain structure than the base metal and weld metal.Keywords: smaw welding, sliding adaptive two axis, electrode angle, seam v.
Studi Eksperimental Pengaruh Variasi Mekanis Empat Batang Pada Mesin Pengayak Terhadap Kapasitas Produksi Ayakan Didi Syamsunarto; Yohanes Yohanes
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 5 (2018): Edisi 1 Januari s/d Juni 2018
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Abstract

Sifting is a method of grouping granules, which will be separated into one or several groups, thereby separable between the particles passing through the sieve (fine grain) and remaining in the sieve (coarse grain). Specific grain size that can still pass through the sieve, expressed as a boundary grain. In the process of sieving the solid is dropped or thrown onto the sieving surface. Under-sized or undersized particles, or passes (fines), pass through a sieve opening, medium above size or large (oversized), or tails do not pass in sifting. Sifting From the mechanical making of four sticks and the test of the wheat flour with 100 and 200 mesh using DOL250-2 type AC motor, with time of 5 minutes and 229 rpm rotation to sift the flour weighing 500 gr with stem size 75 mm mesh 100 produce the average production was 446.6 gr and the mesh 200 averaged 134.6 grams with the test three times.Keywords : machine, flour, sieving, mesh.
Eksperimental Penambahan Flywheel Sistem Penggerak Mesin Las Gesek Rotari Dengan Variasi Dimensi Permukaan Gesek Pada Pengelasan Gesek Rotari. Ichsan Rahmadani Syawal; Yohanes Yohanes
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 6 (2019): Edisi 1 Januari s/d Juni 2019
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Rotary friction welding is one of mechanical welding by utilizing the friction of the two joint surfaces to cause heat which is used for the welding connection process. The friction surface afface the rate of heat flow generated from the torque and rotation an axial force (forging) to suppress the friction surfaceThe occurrence of pulses (shock power) at each stage of the friction welding process results in excessive load on the driving motor. In this study theshape and dimensions of the surface, namely the length of the constant champer, 4 mm with angular variations of 150, 300,450 as well as varying the addition of the flywheel to the drive system. Optimal welding results fromspecimen 45,specimens using type II flywheel with tensile strength of 480.44 MPa.Keywords: flywheel, friction surface, rotary friction welding, pulse rate, forging
Simulasi Pengaruh Variasi Sudut Chamfer Forging Terhadap Penyambungan Material Mild Steel Pada Las Gesek Rotari Muhammad Nafis; Yohanes Yohanes; Ridwan Abdurrahman
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 6 (2019): Edisi 1 Januari s/d Juni 2019
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Abstract

The welding process is carried out in the solid phase. The friction welding process that occurs from the direct conversion of mechanical energy into friction into thermal energy. The process of friction between two surface objects in the direction of the direction. The connection process is carried out on the surface with a flame temperature (melting point), so that the connection can be ascertained between the surface of the material being welded and the joints of the same nature. In the previous study, measuring when measuring data when testing, the exact time when loading forging, the temperature at the time of welding and the temperature propagation of the specimen along. Therefore, to find out the problems needed for this, it is necessary to do an evaluation before conducting welding so that we can get groupings or predictions to do welding with good results, and with this simulation it is also expected to be studied according to the temperature of the specimen on welding requirements. From the simulation results, the exact time and temperature for giving an average forging pressure at each angle is 30° (132.27 seconds; 1.070,2 °C), 45° (127.91 seconds; 1.070,1 °C), 60° (123 ,77 seconds; 1.071,2 °C).Keywords : Friction, Steel, Chamfer Interface Area, Forging
Analisa Kekasaran Permukaan Hasil Pemotongan Orthogonal Pada Proses Pemesinan Turn-Milling Muhammad Iqbal; Yohanes Yohanes; Anita Susilawati
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 6 (2019): Edisi 1 Januari s/d Juni 2019
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Abstract

Turn-milling is a machining method with a system that combines turning and milling operations, which the work-piece and the cutting tool perform a rotating movement simultaneously. The purpose of this study was to investigate and analyze the surface roughness of the orthogonal cutting process in turn-milling machining. The rotary milling test was performed the orthogonal method and produces a final surface roughness that varies with tests carried out for the work-piece speeds and the feed speeds. The resulting surface quality was also influenced by the parameters of the machining process in the form of work-piece loadings and feed rates. This study revealed the higher rotation of the work-piece, the higher the value of the surface roughness. Based on the roughness class, the rotational parameters of the work-piece for 350 rpm with a feed speed of 0.051 mm that was good parameters in this study, which resulting the lowest surface roughness average value of 2.439 μm.Keyword : Turn-milling, orthogonal turn-milling, rotation, feed, roughness.
Estimasi Kapasitas Dan Titik Berat Pada Pembuatan Kapal Jaring Tradisional Di Galangan Kapal Bagan SiapiApi Kabupaten Rokan Hilir Menggunakan Software Autodesk Inventor 2010 Pindo Evans Manuel Damanik; Yohanes Yohanes; Muftil Badri
Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains Vol 1, No 2 (2014): Wisuda Oktober Tahun 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Teknik dan Sains

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Abstract

Jaring ship building in Bagan Siapiapi Kabupaten Rokan Hilir Riau in general is traditionally. One example that still use the traditional way is how to determine the capacity and center of gravity. In estimating the capacity and gravity in Bagan Siapiapi Kabupaten Rokan Hilir Riau is not accurate so as to anticipate it, Bagan Siapiapi  community change the shape and size of the vessel at the time of testing The purpose of the study to estimate the capacity and center of gravity in Bagan Siapiapi. This research is a study case method that uses a single fishing vessel industry is in Bagan Siapiapi. Jaring’s ships  measured ship's main dimensions, construction Linggi, keel construction, joist construction, foundation construction machinery, building construction on the upper deck, and wood density testing, subsequent construction of ships drawn using Autodesk Inventor 2010 software. Capacity and center of gravity jaring ship calculations using Autodesk Inventor 2010 software. From the data processing capacity of jaring Bagan Siapiapi Chart for 7.093 kg and an emphasis on jaring ship Bagan Siapiapi is at position: (1) unloading condition (0,9  mm; 888,5 mm ;-162,5 mm) the front view with the tilt angle of the ship experienced a shaky  89,24o and  -84o side view (2) maximum load condition  ( 0,7 mm; 976,7 mm;  -600,4 mm) the front view with the tilt angle of the ship experienced a shaky -89,8o and side view 80,03o.Keywords: jaring ship, capacity, center of gravity, construction
Co-Authors Aguswandi Aguswandi Alfadeny Anjer Farino Ambri Ambri Anak Agung Gede Sugianthara Andika Saputra Andreas Prasetyo Angga Pranata Angga Septiawan Anita Susilawati Arief Rachman Widyanto Aryo Sasmita Budi Rukhyana Darius Andana Haris Derik Oktarian Devid Vio Sandri Didi Syamsunarto Djoko Widodo Evon Yulianto Fajar Pratama Putra Frandi Barasa Gede Sukadarmika Halal Putra Purba Hambra Hidayatullah Handri Gustiar Helen Susanti Helmi Candra Hendinto Simanihuruk Hendro Sulistiono Ichsan Rahmadani Syawal Irvan Gunawan Jeanny Pragantha Jery Indra Putra Harianja Jon Prisno Riduan Kartika Andi Kentris Indarti Linawati Linawati Muftil Badri Muhammad Iqbal Muhammad Nafis Muhammad Ryan Detra Mustafa Akbar Panji Adino Pepi Setya Bakti Pindo Evans Manuel Damanik Radinal Fernandes Ridwan Abdurrahman Romy Romy Roni Wandra Rudiansyah Rudiansyah Satriadi Satriadi Satriardi Satriardi Sistro Maldini Sihombing Tazkiyah Ahcmad Teddi Febriardi Mulia Tri Lestari Uberkis Uberkis Wenny Wenny Windodo Suwanda Yuhelson Yuhelson Zainal Abdi