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"Vol 4, No 1 (2018): Widyariset"
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<![CDATA[A STUDY OF STRESS CORROSION CRACKING RESISTANCE FOR COLD FORMING PLASTIC DEFORMED Cu-30Zn ALLOY ]]>
<![CDATA[Gadang Priyotomo]]>;
<![CDATA[Akhmad Faizal]]>;
<![CDATA[Rini Riastuti]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.29-36
<![CDATA[Cu-30Zn alloy has good atmospheric corrosion resistance. It is mainly used as automotive radiator cores, ammunition component, lamp fixture, flashlight shells and kickplates. Cold rolled Cu-30Zn with deformation degree 33,87% at 300OC was tested its Stress Corrosion Cracking (SCC) property. Stress corrosion cracking (SCC) of a Cu–30Zn has been investigated using Mattsson solutions 0,5 M (NH4)2SO4 + 0,05 M CuSO4 in room temperature by using a constant load method. Cu-30Zn has a weakness on stress corrosion cracking in ammonia environment (mattson solution). Scanning electron microscope (SEM) testing indicated the failure of cold roll Cu-30Zn was a transgranular cracking. Furthermore, cracking occued at stress below yield stress. Energy dispersive Spectroscopy (EDS) test exhibited dezincification indication on fracture surface. The visual examination of surface morphology on alloy showed discoloration from yellow to red. Homogenized Cu-30Zn showed better SCC resistance than cold rolled Cu-30Zn.]]>
<![CDATA[ANALYSIS OF CLIMATOLOGICAL THERMAL COMFORT IN DKI JAKARTA USING HEAT INDEX (HUMIDEX) ]]>
<![CDATA[Trinah Wati]]>;
<![CDATA[Riri Indriani Nasution]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.89-102
<![CDATA[Interactions between human and environment about the influence of the physical atmosphere’s state or weather on human is expressed in com- fort level. The complex relationship between health and weather factors with human comfort is defined as biometeorological index. One of the biometeorological indices is heat index called as Humidex. Studies about Humidex in Jakarta were conducted using climate data stations of Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), namely air temperature, relative humidity and wind speed daily average during 1985 to 2012. The purpose of this study was to determine the level of thermal comfort using heat index Humidex in Jakarta and its climatological trends during 1985 to 2012. Comparative analysis between Humidex and the wind speed and also with the number of vehicles in Jakarta were conducted to determine their impact to the heat index in Jakarta. The results showed that the Humidex monthly average in Jakarta ranged between 36,1 °C and 39,5 °C. Humidex monthly pattern had two peaks with the first peak was on May and the second one was on November, while the lowest value was recorded on August and January. Humidex in Jakarta tended to increase between 0.05 °C and 0.08 °C with its coefficient of determination (R2) was between 0.36 and 0.71. The effect of wind speed to Humidex was lowering the value of Humidex which increased the thermal comfort. Meanwhile, the number of vehicles showed a tendency to grow exponentially, which affected the further decline in thermal comfort level in Jakarta.]]>
<![CDATA[WASTEWATER SPECIFIC EMISSION FACTOR FROM COMMUNAL WASTEWATER TREATMENT PLANT (WWTP) ]]>
<![CDATA[Reni Nuraeni]]>;
<![CDATA[Amallia Ashuri]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.37-48
<![CDATA[Greenhouse gasses (GHG) that produced by anaerobic digestion of wastewater consists of CH4 gas and NO2 gas. Beside the data of specific activity, the specific emission factor also plays important part to determinate GHG emission. The aim of this paper is to know specific emission factor value from communal wastewater treatment plant (WWTP), as an input to determinate GHG emission for determination of GHG emission reduction rate. The data was collected by taking sample of BOD, CH4 gas, and CO2 gas from communal WWTPs. Sampling location were communal WWTPs in Jakarta City, Bandung City, and Yogyakarta City. Those WWTPs using anaerobic baffle reactor as their treatment system with capacity varied between 40-200 EP. The parameters were BOD and CH4 that measured using grab sampling in the morning and evening. Data analyzed by quantitative methods. The specific emission factor value was determined from CH4 gas measurement which affected by wastewater treatment unit dimension, gas catcher chamber, and air suction pump capacity. The analysis results showed specific emission factor for communal WWTPs from the three cities is 0.00171 kg CH4/kg BOD. The value has bid difference when compared to IPCC’s default that is 0.48 kg CH4/kg BOD. This is due to the formation of CH4 gas and CO2 gas was strongly influenced by environmental condition in real time condition. This factor is not taken into consideration in IPCC’s default.]]>
<![CDATA[THE EFFECT OF CHARGING CONDITION FOR CONDUCTED EMISSION VALUE OF INFORMATION TECHNOLOGY EQUIPMENT ]]>
<![CDATA[Agung Yanuar Wirapraja]]>;
<![CDATA[Ika Prawesty Wulandari]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.103-112
<![CDATA[Currently, IT devices, especially mobile phone and notebook, have become a staple for humans. These devices can’t be separated from human activities. Mobile phone or notebook using those are too often can lead people to conduct any charging process when that device is being used. In general, there are three conditions for any devices when the charging process is being performed, such as: off, standby, and normal use (music on). This research objective is to compare the result on conducted emis- sion testing when mobile phone and notebook at the plugging charge for the conditions: off, stand by, and normal use (music on). Testing method refers to CISPR 22 Standards at Clause Mains Terminal Disturbance Voltage. Testing result for mobile phone and notebook show that all of testing sample perform conducted emission value with quasi peak value meet the requirement of CISPR 22. The amount of 80% testing sample, perform the highest quasipeak margin value when the off condition of devices.]]>
<![CDATA[INFLUENCE OF CARBON AND NITROGEN ADDITION ON THE CORROSION RESISTANCE OF Co-28Cr-6Mo-0,8Si-0,8Mn-0,4Fe-0,2Ni ALLOYS ]]>
<![CDATA[Fendy Rokhmanto]]>;
<![CDATA[Cahya Sutowo]]>;
<![CDATA[Ika Kartika]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.1-8
<![CDATA[Cobalt alloys is one of the implant materials that is used in orthopedic and dentistry, because of its biocompatibility, good mechanical properties, and high corrosion resistance. The mechanical properties and corrosion resistance can be enhanced by thermomechanical treatment and addition of alloying element. Carbon and nitrogen were added to enhance mechanical properties and high corrosion resistance. Effect of carbon variation and nitrogen to the corrosion resistance in Co-Cr-Mo (CCM) alloys were measured by corrosion measurement system (CMS) device in Hank’s Solutions after thermomechanical treatment process. Corrosion rate of Co-Cr-Mo alloys with carbon variation dropped to 5.8 x 10-4 mmpy and 5.2 x 10-4 mmpy with carbon variation and nitrogen. Decreasing corrosion rate indicated that the corrosion resistance of alloys is increased with the addition of carbon and nitrogen.]]>
<![CDATA[VISION SYSTEM DEVELOPMENT IN ECCENTRICITY TESTING FOR KWH METER UPPER BEARING ]]>
<![CDATA[Emilham Mirshad]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.49-60
<![CDATA[Eccentricity measurement techniques are developed to ensure optimization of operational works, either for large or small objects such as upper bearing kWH meter. Small object eccentricity testing has been done by using precise and sensitive touch trigger probing and a special sofware that makes it expensive. This study developed a more economical vision systemin eccentricity testing. It consists of bearing holder and CCD microscope as an image recorder and computerized image processing. It uses three tested bearing during image recording process, which obtained 12 images from each tested bearing taken from every 30o angle, and one image as registration reference. Image registration process is conducted to correct imperfections bearing mounting into its holder and use centroid method to test the eccentricity of upper bearing kWH meter. This study is succeed in making an eccentricity testing prototype of upper bearing kWH meter which obtained result of 2nd bearing has its largest standard deviation. From all standard deviation value obtained that x -axis (horizontal) standard deviation is larger than y-axis (vertical) which means that detection of x direction is more accurate than y direction. To enhance precision image acquisition in the next study, it is expected the use of a computer system with homogeneous illumination is enabled.]]>
<![CDATA[CORROTION RATE AND MORPHOLOGY OF POROUS METAL ALLOY Mg-Ca-Zn WITH CaCO3 AS FOAMING AGENT ]]>
<![CDATA[Aprilia Erryani]]>;
<![CDATA[Franciska Pramuji Lestari]]>;
<![CDATA[Dhyah Annur]]>;
<![CDATA[Muhammad Ikhlasul Amal]]>;
<![CDATA[Ika Kartika]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.9-20
<![CDATA[Magnesium alloy is a material that has been developed as a biodegradable implant material in orthopedic applications. Magnesium alloys have good biocompatibility, biodegradability, and good mechanical properties which make them have the potential to be used as a biomedical material. The main objective of this paper is to investigate corrotion rate and morphology after corrotion of biocompatibility of implant-based alloys Mg-Ca-Zn with CaCO3 as a foaming agent. Mg-Ca-Zn Alloy was made by the method of powder metallurgy with the addition of CaCO3 as a foaming agent with three variations of composition (96Mg-Ca-3Zn-CaCO3, 91Mg-Ca-3Zn-5 CaCO3, and 86Mg-Ca-3Zn-10 CaCO3 wt%). Sintering process was carried out at 600 °C and 650 °C with a holding time of five hours. Corrosion test was performed using G750 Gamry Instrument in accordance with ASTM standard G5-94. Simulated body fluid electrolyte used is Hank's solution with a pH value of 7.4 and a temperature of 37 °C. Then the analysis of the microstructure after corrosion test was conducted using scanning electron microscopy (JEOL, JSM-6390A Japan) equipped with energy dispersive spectrometry data (EDS). Alloy corrosion rate of Mg-Ca-Zn-CaCO3 increases with the amount of CaCO3 in the alloy and the temperature rise in the sintering. From the test results, the smallest corrosion rate is in the alloy 91Mg-Ca-3Zn-CaCO3 at 600 °C sintering (58.3045 mpy) and the highest occurs in alloy 86Mg-Ca-3Zn-10CaCO3 at 650 °C sintering (91.4007 mpy). Surface morphology of the alloy after the corrosion process is the type of volcano. This localized corrosion occurs where an electrochemical reaction takes place to form a distinctive structure with a circle and a hole in the middle.]]>
<![CDATA[LOCAL MATERIAL TESTING FOR PAVEMENT MATERIAL ON REMOTE AND OUTMOST ISLAND ]]>
<![CDATA[Iwan Susanto]]>;
<![CDATA[Nono Nono]]>
<![CDATA[ Widyariset Vol 4, No 1 (2018): Widyariset ]]>
Publisher : <![CDATA[Pusbindiklat - LIPI ]]>
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DOI: 10.14203/widyariset.4.1.2018.61-74
<![CDATA[Road infrastructure development in remote and outmost islands such as Mentawai, Aru, and Morotai faced a problem i.e. dificulty in the availability of standard material. The standard material had to be transported from other areas that taking a long time and high cost of transportation. In fact, the three islands had abundant materials. However, there was no study conducted to examine the properties of the local material. The study aim was to find out the physical properties of pavement material that will be the basis of pavement design. The research began with the selection of material, discussion with experts, coordination with involved parties, site observation, and laboratory test. The analysis of testing result used comparative analysis that compared test result to certain standard. Based on the analysis, local material from Mentawai Islands was suitable for foundation layer with cement stabilization 6%. Coral from Aru Island and limestone from Momojiu Morotai Island could also be utilized for foundation layer. Limestone from Rau Morotai Island utilized for aspalt mixture. Sand from Aru Island and sea sand from Morotai Island could be used for aspalt mixture and concrete cement mixture.]]>
