PENGARUH KECEPATAN TORCH DAN JENIS NYALA API TERHADAP KEKERASAN PERMUKAAN BAJA KARBON PADA PROSES AUTOMATIC FLAME SURFACE HARDENING

Surface hardening of metal is a method to enhance the surface hardness of a metal. The surface­ hardened metal possesses higher scale of hardness on the surface than in the core (the core remains  ductile).  The objective of  the surface hardening  in  this  research  is  to obtain    the highest  value of  hardness of the carbon steel surface  subjected to flame hardening. The output of this research could be  applied to small scale industries of metal surface hardening to increase their  product quality.  This research utilized an automatic flame surface­hardening device. The surface hardening is  performed by heating  the specimen surface  followed by quenching.  The  flame of  oxy­asetylene  is  utilized to heating up the metal’s surface while the cooling is performed by water pumped from water  reservoir.  The speed and the flame of the torch are varied in this research. The speed of the torch and  the cooling nozzle are regulated by inverter.  The type of the flame is regulated through the oksigen and  asetylene valves on the heating torch.  The result of the testing shows that the best hardness value of the surface achieved when the  torch speed is 28 mm/min and the type of the flame was carburation.   The hardness of the surface of  the specimen are 879,10 HV and 232,80 HV under the surface. Case depth on this specimen reaches  1,4mm from surface.  The microstructure imaging shows the martensitic phase on the surface of the  specimen while the middle and the bottom of the specimen shows the pearlit and the ferrite phase  respectively.  That’s why  the specimen is hard on the surface while  the core and  the bottom of the  specimen remain ductile. Keywords: flame hardening, hardening, carbon steel, quenching, martensi

Decreasing in Acid Number of Patchouli Oil by Different Natural Adsorbent and Variation of Contact TIME

One way for improving (of improving atau to improve) the quality of patchouli oil was to reduce the acid number. Acid number could be reduced with the use of natural adsorbents. The decreasing percentage acid number of patchouli oils using adsorbents zeolites, bentonite, rub ash, and activated carbon, respectively 4.71 %; 1.45%; 7,84%; and 4.64%. The contact time could influence the decrease in acid number of patchouli oil. The longer the contact between adsorbent and oil could caused a decrease in acid number. Maximum contact time for rub ash was 15 hours with a maximum adsorption capacity of 14,34% for 0.1 gram adsorben

Kekuatan Tarik Baja St 37 Pada Proses Las Oksi - Asetilen

Welding is a process of joining metals by pressure when the metal are hot. Welding planning to get a good result is a complicated process. A welding work should be planned about its way, observing the material and its type of welding. The procedure of welding involves: choosing parameter of welding type of being used, type of filling metal, type and also the thickness of metal plat and condensor as mediator and some standartd condition in welding in which the parameters will effect the mechanical characters of welding.An example of welding type is Oxy-Acetyline Welding (OAW). The heat being produced is lower, so this kind of welding is good to weld the thinner stainless steel ( 3 mm). The thicker one needs a longer welding time so that, it is not economic. This kind of welding is good for a thick stainless steel before using electrical welding. This welding is used for a simple construction that is not need strength, example in the fenceof a house or for welding a house hold.This process, uses material of ST-37 steel plate with 3 mm thickness. Weld with 1-2 mm in space between thew both material. Set the barometer up on the acetyline bottle is about 0,5 bar and the pressure on oxyigene bottle is about 2,5 bar, and a weather condensor. Use RBuZn-A, RBuZn-B and RBuZn-D as filling metal. Then do test

Persepsi Dan Respon Masyarakat Teriiadap Akt1vitas Pemegang Iuphhk PT. Suka Jaya Makmur

This study aimed to examine (1) perception and public response to forest management activities undertaken by companies IUPHHK PT. Suka Jaya Makmur . ( 2 ) The relationship between the public perception of the public response to the activities of the holder IUPHHK PT. Suka Jaya Makmur. Determining the location of the observations were made at random by taking samples at specific locations. Based on the public perception of the value of the public response to the activity obtained IUPHHK holder PT. Suka Jaya Makmur tend to Neutral. Based on the overall perception of value indicators such as employment opportunities, business opportunities, income, social services , TPTJ, an Environmental damage, and the potential for REDD emission reductions of the public perception of the activity obtained IUPHHK holder PT. Suka Jaya Makmur tend Netral. Hasil research based work opportunities, business opportunities, social services, TPTJ system, as well as REDD emissions reduction by calculating Chi Square X2 hitung > X2 tabel the relationship with the public response to the activities of the holder IUPHHK PT. Suka Jaya Makmur at the significant level of 95%, with provisional estimates received by the results of research that associative hypothesis is accepted, while the level of income and the absence of environmental damage relations with the public response. Based on the value of the overall community response obtained public response to the activities of the holder IUPHHK PT. Suka Jaya Makmur tend to Neutral. Key Word:Perception, public response, forest management

Perbaikan panel-panel bodi untuk SMK/MAK kelas XI semester 1

Ruang lingkup dalam pembahasan buku teks ini berkenaan dengan pengetahuan dan keterampilan yang dibutuhkan dalam pekerjaan perbaikan bodi otomotif yang meliputi cara pengelasan dengan gas oxyacetylene (karbit) dan las titik, pengelasan CO2 (MIG) dan las elektrod, pemanasan termal dan pemotongan termal, pengetokan panel cara hot & cold shrinking, perataan panel dengan bodi filler/dempul, pembentukan panel bodi, penambalan & peralatan panel, pengelasan panel bodi sesuai bentuk aslinya, pelepasan panel pintu, perbaikan dan pemasangan sesuai buku manua

MFCS 2 IN 1 : MICROBIAL FUEL CELLS PENGOLAH AIR LIMBAH DAN PENGHASIL LISTRIK (ALTERNATIF : LIMBAH ISI RUMEN SAPI DENGAN PENGARUH VARIASI COD DAN PH)

Seiring dengan meningkatnya pertumbuhan populasi penduduk, konsumsi masyarakat akan pangan pun meningkat. Salah satu kebutuhan akan protein hewani dari daging sapi. Di kota Semarang frekuensi pemotongan hewan sekitar 40-50 ekor sapi dan meningkat hingga 100 ekor sapi perhari menjelang lebaran (Suaramerdeka, 2012). Frekuensi pemotongan yang tinggi ini berpotensi untuk menimbulkan limbah. Limbah yang berasal dari rumen sapi fasa cair mengandung konsentrasi COD sebesar 5.500-7000 mg/L (Padmono, 2005). Oleh karena itu perlu dilakukan pengolahan sebelum dibuang ke badan air penerima. Reaktor terbaru dari proses pengolahan anerobik yang sering digunakan dalam pengolahan air limbah yang saat ini telah banyak dikembangkan yaitu microbial fuel cells. Menurut (Aeltermn et al. 2006 dalam Zhang, 2012) microbial fuel cells (MFCs) adalah reaktor bioelektrochemical yang dapat mengkonversi energi kimia dari zat organik pada air limbah menjadi listrik dengan katalis dari mikroorganisme. Penelitian dengan MFCs dual chamber dengan substrat limbah rumen sapi fasa cair dengan variasi pH 7 (netral), pH 5 (asam), pH 9 (basa) ini menunjukan bahwa variasi pH berpengaruh terhadap penurunan konsentrasi COD dan produksi listrik pada pengolahan air limbah rumen sapi menggunakan reaktor Microbial fuel cells. Rreaktor dengan varioasi pH netral produksi listrik terbesar adalah 219,0916 mW/m2, sedangkan variasi pH asam dan pH basa power density terbesar 108,5341 mW/m2 dan 174,5589mW/m2 . Penurunan COD optimum pada hari ke 10 untuk pH netral COD 167,5 mg/L pada reaktor N1 (memenuhi baku mutu), pH asam COD 185,2 mg/L pada reaktor A2 (memenuhi baku mutu), dan pH basa 292,1 mg/L (belum memenuhi baku mutu). Efisensi penyisihan optimum pada pH netral 94,8%, pH asam 94,4% dan pH basa 88,1 %. Pada reaktor dengan variasi substrat pH netral power density, penurunan COD dan efisiensi penurunan lebih baik dibanding dengan pH asam dan basa, meskipun demikian mikroorganisme dalam limbah rumen sapi tetap dapat berkembang biak dalam kondisi substrat pH ekstrim. Kata Kunci : MFCs, limbah rumen sapi, pH, power density, CO

Evaluasi Kesuburan Tanah Untuk Pertanaman Tebu Di Kabupaten Rembang, Jawa Tengah / Evaluation of Soil Fertility to Sugarcane at Rembang District, Central Java

Rembang District is an area of Central Java production center which has the main characteristics dominated by dry land. Dry land issues related to the low availability of water and nutrients. It determines the area of soil fertility conditions. Soil fertility affects the growth, production, and yield of sugarcane. Study of soil fertility conducted through the soil fertility evaluation methods of chemical analysis of matching data criteria soil with soil chemical properties. The sampling method is based on the land unit mapping. Soil fertility assessment based on the analysis of soil chemical properties that include cation exchange capacity (NH4Oac extraction method), pH (pH meter), C-Organic (Walkey and Black method), base saturation (estimation of pH mapping), P2O5 (Olsen and Bray-1 method), and available K (flamephotometer). Soil fertility in Rembang district classified into low until moderate. The limiting factor in soil fertility were consists of nitrogen content, cation exchange capacity, pH, available P2O5, organic carbon, and available

Analysis of Biomass and Carbon Stock on Mangrove Forest Ecosytem in North Coastal Area of Rupat Island Riau Province

Analysis of biomass and carbon stock on mangrove forest ecosytem in coastal area of North Rupat Riau Province has been conducted in January 2016. The method used in this study is a survey method with purposive sampling technique. The study showed that the potential mangrove biomass was directly proportional to mangrove carbon stocks. The average yield of biomass, carbon stocks of soil organic carbon and CO2 sequestration on mangrove forest was reserves amounted to 68,64 tons/ha , 904,75 tons/ha and 251,39 tons/ha, while the average yield of total carbon stocks was 973,31 tons/ha