PENGARUH PRE-STRAIN TERHADAP DISTORSI DAN PERAMBATAN RETAK FATIK SAMBUNGAN LAS MIG PADA PENGELASAN BAJA SS400

IGNATIUS HENRY ADI NAGORO. NIM: S951302003, 2015. Pengaruh Pre-Strain Terhadap Distorsi Dan Perambatan Retak Fatik Sambungan Las Mig Pada Pengelasan Baja SS400. Komisi Pembimbing I: Dr. Triyono, S.T., M.T. Pembimbing II: Dr. Kuncoro Diharjo, S.T., M.T. Tesis Program Studi Magister Teknik Mesin. Program Pasca Sarjana. Universitas Sebelas Maret Surakarta Penelitian ini bertujuan untuk mengurangi distorsi pada proses pengelasan dengan metode pre-strain, dan mendapatkan informasi tentang pengaruh pre-strain terhadap karakteristik mekanis hasil pengelasan, juga untuk mengetahui pengaruh pre-strain terhadap laju perambatan retak fatik. Pengukuran distorsi hasil pengelasan spesimen yang di pre-strain menunjukkan bahwa pre-strain dapat mengurangi distorsi pengelasan sebesar 50% hingga 74%. Hasil Foto Makro mengindikasikan bahwa peningkatan ukuran penetrasi daerah las dan HAZ terjadi karena peningkatan derajat sensitivitas logam induk SS400. Hasil Foto Mikro pada logam induk yang di pre-strain menunjukkan adanya rekristalisasi statis sehingga menghasilkan twin boundaries yang membuat ukuran butiran nengecil dan merubah garis sumbu butir ferrite dan pearlite. Hasil Foto Mikro di daerah las menunjukkan bahwa pre-strain mengakibatkan terjadinya strain hardening dikarenakan adanya dislokasi atom ferrite dan pearlite sehingga ukuran butiran pada logam induk menjadi lebih kecil. Sementara itu, pre-strain juga mengakibatkan pertumbuhan retak pada celah batas butir yang sangat berpengaruh pada pembentukan fasa saat dilakukan pengelasan. Pada daerah lasan, proses strain hardening mengakibatkan peningkatan fasa widmanstaten ferrite (WF) sehingga dapat meningkatkan kekuatan lasan. Pengujian fatik spesimen CT tanpa pre-strain dan yang dipre-strain 1%, 3%, dan 5% yang dilakukan pada suhu ruangan dengan rasio pembebanan 0,1 mereduksi siklus fatik seiring dengan peningkatan tingkat pre-strain. Penurunan jumlah siklus fatik terjadi karena pengaruh peningkatan dislokasi densitas sehingga menghasilkan tatanan struktur butiran baru dengan tingkat dislokai densitas berbeda. Kemudian, medan gaya yang dihasilkan dari dislokasi struktur menurunkan slip plane dan homogenitas deformasi plastis. Kata Kunci : metode pre-strain, SS400, distorsi pengelasan, regangan sisa, perambatan retak fatik, fraktograf

FACTORS AFFECTING POST-OPERATIVE PAIN AFTER DOPPLER GUIDED HEMORRHOID ARTERY LIGATION AND RECTO-ANAL REPAIR (DGHAL-RAR) OF INTERNAL HEMORRHOID

Background: DGHAL-RAR is new modality for grade II-IV internal hemorrhoid treatment. It is developed to reduce post-operative pain that mostly found in traditional hemorrhoidectomy even in Stappler hemorrhoidopexy. However, in clinical practice some patients are complaint of moderate until severe pain. This study is intended to know factors affecting the post-operative pain after DGHAL-RAR of internal hemorrhoid.Methods: A series of 61 grade II-IV internal hemorrhoid patients, underwent DGHAL-RAR in St Elizabeth Hospital, Semarang Indonesia, period of August 2012 – March 2014 were analyzed prospectively. Age, sex, grade, removing of thrombus  either internal or external, anal fissure, removing of hypertrophic anal papilla, removing skin tag, anal laceration due to procedure, were analyzed to know it relation with post operative pain in 24 hours, 48 hours and 7 days post-operatively. VAS for pain (0–10) were used to assess the degree of pain. Mann-Whitney method was used for univariate analysis, while Kruskal-Wallis and Median method were used for multivariate analysis.Results: After multivariate analysis variables that significantly influence post operative pain on 24 hours were removing of internal thrombosis, removing of anal papilla hypertrophy and anal laceration, on 48 hours were removing of external thrombosis, removing of anal papilla hypertrophy and anal laceration and  on 7 days were the same with on 24 hours.Conclusion: Factors that affecting post-operative pain after DGHAL-RAR  for grade II-IV internal hemorrhoid were removing of both internal and external thrombosis, removing of anal papilla hypertrophy and anal laceration due to DGHAL-RAR procedure. Keywords: Internal hemorrhoid, Hemorrhoid artery ligation and recto-anal repair, thrombosis, anal papilla hypertrophy, anal laceration

PENGARUH LINGKUNGAN KERJA, STRES KERJA DAN MOTIVASI KERJA TERHADAP KINERJA KARYAWAN

Perusahaan melakukan peningkatan terhadap kinerja karyawan dengan melakukan pengembangan pada sumber daya manusianya. Tujuan Penelitian ini adalah untuk menguji beberapa variabel yaitu lingkungan kerja, stres kerja, motivasi kerja untuk mengetahui pengaruh pada kinerja karyawan. Pengambilan data dilakukan melalui survei langsung dengan instrumen kuesioner pada karyawan CV. Muda Jaya Utama Sidoarjo Jawa Timur. Olah data yang dilakukan dengan menggunakan analisis regresi linier berganda. Temuan riset menyatakan bahwa lingkungan kerja dan motivasi kerja berpengaruh positif terhadap kinerja karyawan sedangkan stres kerja berpengaruh negatif terhadap kinerja karyawa

Kualitas Airtanah di Dataran Borobudur Kabupaten Magelang Propinsi Jawa Tengah =

The aims of this research are : 1) to understand groundwater quality distribution in Borobudur Plain2) to analyze the relationships between population density and groundwater quality in Borobudur Plain. A collection of field data has been done with the help of topographic map, geologic map, landform map and land use map from previous research. A collection of geological data includes observation kind of stones, relation, and thickness. Groundwater data collection i.e. temperature measurement, pH, electrical conductivity, water level, and depth of the well has been done as random sampling method in Borobudur Plain. Sampling for groundwater chemical and biological analysis used stratified random sampling from electrical conductivity group with range less than 500 pmhos/cm, 500-1000 iimhos/cm and more than 1000 pmhos/cm. Chemical and biological analysis is meant for making an illustration groundwater quality in Borobudur Plain. The result of this research showed that groundwater quality in Borobudur Plain is distinguish on four lithological units, i.e.: 1) silty sandstone unit, which is formed from recurrence silty sandstone, tuff siltstone, conglomerate, fine-coarse tuff sandstone with inserted young Merapi breccia2) tuff sandstone unit, which is formed from tuff sandstone with recurrence tuff3) colluvial deposit unit, which is formed from free material silt to boulder grain size4) alluvial deposit unit, which is formed from free material fine sand to cobble. Tuff siltstone as impermeable layer forms the boundary groundwater in Borobudur Plain, as an unconfined groundwater and a confined groundwater. Both groundwater from unconfined and confined aquifer are used as people groundwater resources. The region was arranged silty sandstone unit i.e. Wanurejo, Candirejo, and Ngargogondo that decreasing groundwater quality than Bumiharjo, Borobudur, and Tanjungsari until very dangerous if used drinking water. This showed that maximum drinking water quality standard for drinking water is showed DHL, Cat., Fe, NO3-, Cl- found at silty sandstone unit in Candirejo, Wanurejo, and Ngargogondo. Relationship between population density and groundwater quality showed that increasing population density at settlement land use in Borobudur Plain cause decreasing groundwater quality if the water is used for drinking water, especially shown by coliform concentrations. Settlement land use as the high population density cause groundwater quality decreasing. Key words : groundwater characteristics - population density -groundwater qualit

Influence Types of Startup on Hydrothermal Scheduling

The energy costs of a power plant consist of startup cost and cost of power usage. In contrast to the existing literature, this study introduces at startup cost based on the duration of thermal power plant downtime. The approach of startup cost function in this research is done by using startup type. Startup of a steam power plant depends on its condition. Generally, there are three types of startup the power plant when the turbine temperature is still very high, i.e. hot start, very hot start and very-very hot start. This paper uses multistage optimization to solve the problem of hydrothermal scheduling with including the startup type cost in the objective function. The simulation results showed operating cost savings when the objective function for optimization also consider the cost based on startup type i.e. when compared with the optimization result which the objective function does not take the cost of startup type

Aplikasi Penginderaan Jauh Untuk Identifikasi Bentuk DAS Serang Di Kulon Progo

The aims of this research is to determine the shape of Serang drainage basin, Kulon Progo, DIY baseon the appearance recorded on the image of SRTM. Research method of remote sensing imageinterpretation of SRTM for the determination of Serang drainage basin and then calculate themorphometry of drainage basin in terms of the length of the main river, the width of the drainage basin,and the around of the drainage basin by using ArcGIS software. The results of morphometriccalculations is the main river length of 27.25 km, the drainage basin area 305.404 km2, the around ofdrainage basin 107.353 km. Based on these results can be calculated wide drainage basin of 11.207km, the shape of roundness 0.33 so that the Serang drainage basin is classified as a drainage basinwith elongated shape

Commercialization of Medicinal Plants in Java Island, Indonesia

The benefit and transaction cost flow which people earn economically and socially from wild medicinal plant harvesting are addressed in this study.   The objectives of this study are three aspects: defining how many users are involved in utilization of medicinal plant raw materials (MPRM), how users describing their perception and motivation and describing benefit and transaction cost which influence users to harvest the plants. Results showed that utilization of medicinal plants in Java is still widely used as commercial products then medical services. There are 41 stakeholders who involved in this study and the highest motivation and perception in production and industrial clusters are economic interest. But stakeholder's perception and motivation in traditional healthcare cluster is social interest. The different motivation and perception in both clusters causing stakeholder who are work in traditional healthcare lack of market information, but they are important if the government will improve the traditional medicine.  Recommendation of this study is that medicinal plants need further research and product development which can help to expand the medicinal plant culture area in the natural forest.   By this reason, government should develop good political will to increase the medicinal plant resources for public healthcare