Karakteristik Sifat Mekanik dan Struktur Mikro Baja Karbon Sedang Paska Perlakuan Panas Tempering

Abstrak Penggunaan baja karbon rendah banyak digunakan lebih disebabkan karena baja karbon rendah memiliki keuletan yang tinggi dan mudah di machining, tetapi kekerasannya rendah dan tidak tahan aus. Sifat mekanik material baja tersebut dapat diperbaiki dengan melakukan beberapa proses perlakuan, salah satunya yaitu perlakuan panas. Baja dapat dikeraskan sehingga memiliki ketahanan aus, peningkatan ketangguhan, dan nilai kekerasannya meningkat dengan inti yang tetap ulet. Penelitian ini dilakukan untuk mengetahui pengaruh variasi tempertur temper dan waktu tahan temper terhadap karakteristik sifat mekanik dan struktur mikro baja karbon sedang S45C paska temper. Temperatur temper yang terbaik adalah pada suhu antara 150oC sampai 250oC, dimana tidak terjadi penurunan nilai kekerasan yang signifikan dibandingkan dengan nilai kekerasan paska quenching. Dengan naiknya temperatur temper mengakibat daya tahan aus benda uji menjadi menurun Kata kunci: S45C, temper,  temperatur, kekerasan, keausan  Abstract Low carbon steel is a type of metal that is widely used because has high ductility and is easy to machining, but has low hardness and is not wear-resistant. The mechanical properties of the steel material can be improved by carrying out several treatment processes, i.e. heat treatment. By proper heat treatment, steel would have good wear resistance, increased toughness, and increased hardness values with a core that remains ductile. This study was conducted to determine the effect of variations in tempering temperatur and tempering time on the mechanical properties and microstructure characteristics of S45C medium carbon steel after tempering. The best tempering temperature is between 150oC to 250oC, where there is no significant decrease in hardness value compared to the post-quenching hardness value.  Keywords: S45C, tempering, temperatur, hardness, wear resistanc

Rancang Bangun Mesin Pengolahan Sampah Plastik High Density Polyethelene Menjadi Bahan Bakar Menggunakan Proses Pirolisis

Penelitian ini membahas mengenai rancang bangun reaktor pirolisis dan bertujuan untuk mengetahui proses kerja dan nilai karakteristik bahan bakar yang dihasilkan. Reaktor yang digunakan mempunyai ukuran diameter 41 cm dan tinggi 66 cm. Proses pirolisis dilakukan pada kisaran suhu 250–450oC. Dari penelitian ini menggunakan bahan baku seberat 5 kg dan didapatkan bahan bakar cair sebanyak 2,5 Kg. Adapun karakteristik bahan bakar cair yang dihasilkan adalah kandungan air 3,22 mm/kg, density 727,6 kg/m3 dan nilai oktan 60,4

PELATIHAN PRAKTIK MESIN CNC BAGI GURU-GURU SMK JAKARTA

Bagi para guru di DKI Jakarta  menurut data sekolah dinas DKI Jakarta banyak guru guru muda di sekolah yang belum mendapatkan pelatihan mesin CNC padahal bagi guru produktif wajib mempunyai sertifikat mesin CNC, terutama guru yang mengajar mesin CNC. Untuk para guru muda yang belum mendapatkan sertifikasi mesin CNC, mengingat bekal pengetahuan dan keterampilan yang minim, rasanya sulit untuk mengajar di Sekolah Menengah Kejuruan. Tujuan kegiatan pengambidian kepada masyarakat ini adalah untuk memberikan pelatihan keterampilan mesin CNC dari dua aspek, yaitu aspek teknologi/teknik tentang mesin CNC, dan aspek pemeliharaan mesin CNC. Khalayak sasaran adalah para guru yang belum mendapatkan sertifikat permesinan dan yang betul-betul berminat dan mempunyai potensi untuk berkembang. Jumlah peserta yang  aktif  adalah  21  orang,  sebagian  besar  berasal  dari  beberapa  Sekolah  Menengah Kejuruan di antaranya, SMKN 1 Bekasi, SMKN 5 Jakarta, SMK Karya Guna dan SMKN 26 Jakarta.  Berdasarkan  evaluasi  yang  telah dilaksanakan,  dari aspek  teknik, pelatihan  ini dapat  dikatakan  cukup  berhasil.  Lebih  dari  90%  peserta  menguasai  teknik  permesinan dengan baik. Untuk aspek manajemen perawatan mesin CNC, Berdasarkan evaluasi yang telah dilaksanakan, dari aspek teknik, pelatihan ini dapat dikatakan cukup berhasil   ABSTRAK For teachers in DKI Jakarta, according to DKI Jakarta school data, many young teacher teachers in schools who have not received CNC machine training have yet to have a CNC machine certificate, especially teachers who teach CNC machines. For young teachers who have not been certified CNC machines, given the lack of knowledge and skills, it is difficult to teach in Vocational High School.The purpose of this community-driven activity is to provide CNC machine skill training from two aspects, technological aspects / techniques on CNC machines, and maintenance aspects of CNC machines.Target audiences are teachers who have not received a certificate of machineryand who are genuinely interested and have the potential to develop. The number of active participants is 21 people, mostly from several Vocational High Schools among them, SMKN 1 Bekasi, SMKN 5 Jakarta, SMK Karya Guna and SMKN 26Jakarta. Based on the evaluation that has been implemented, from the technical aspect, this training can be quite successful. Over 90% of participants mastered the engineering technique well. For management aspects of CNC machine maintenance, Based on the evaluation that has been implemented, from the technical aspect, this training can be quite successfu

RANCANG BANGUN PERANGKAT PENDUKUNG UNTUK PROSES PEMOTONGAN DENGAN PLASMA CUTTING

Material cutting can use a tool commonly called plasma cutting. In general, the plasma cutting used today is still using your own hands or manually, and is not equipped with driving support equipment. This results in the performance of plasma cutting when cutting is not maximized because the movement is relatively not constant. For this reason, it will be designed, manufactured, and tested for cutting support equipment with a rectifier rail system for plasma cutting. In the process of making this supporting equipment, it also uses a threaded rod so that it can move forward and backward by using an electric motor. The design of supporting equipment for the cutting process begins with the creation of a plasma cutting design. Then design the mechanical and electrical components. Then calculate the plasma cutting torque moving forward and backward. Then proceed with the process of making the device and finally testing it. The trial step begins with turning on the compressor, and plasma inverter and preparing steel measuring 4, 6, and 10 mm. Once ready, then proceed with the process of cutting the material and cleaning the material. The results of the cut were then observed visually. The results obtained, that this plasma cutting support equipment can operate properly. The plasma cutting support equipment can cut steel plates with a thickness of 4, 6, and 10 mm very well

RANCANG BANGUN MESIN PENGOLAHAN SAMPAH PLASTIK HIGH DENSITY POLYETHELENE MENJADI BAHAN BAKAR MENGGUNAKAN PROSES PIROLISIS

Penelitian ini membahas mengenai rancang bangun reaktor pirolisis dan bertujuan untuk mengetahui proses kerja dan nilai karakteristik bahan bakar yang dihasilkan. Reaktor yang digunakan mempunyai ukuran diameter 41 cm dan tinggi 66 cm. Proses pirolisis dilakukan pada kisaran suhu 250–450oC. Dari penelitian ini menggunakan bahan baku seberat 5 kg dan didapatkan bahan bakar cair sebanyak 2,5 Kg. Adapun karakteristik bahan bakar cair yang dihasilkan adalah kandungan air 3,22 mm/kg, density 727,6 kg/m3 dan nilai oktan 60,4

Pengaruh Campuran Thinner Terhadap Daya Rekat dan Ketebalan Lapisan Hasil dari Alat Custom Refill Cat Semprot

A custom spray coating refill equipment has been designed and fabrication. For this reason, it is necessary to trial the equipment that has been made. This study aims to determine the performance of custom spray coating refill equipment. For a comparison parameter, coating and thinner mixture variations were conducted to determine the adhesion and thickness of the coating layer formed. The coating used in this experiment was Nitrocellulose (NC) and Polyurethane (PU) thinner. The ratio of coating and thinner mixture used are 1:1.5, 1:2, and 1:2.5. After mixing, the mixture was put into the sprayer using custom spray paint refill equipment. The mixture of coating and thinner was sprayed onto the SPCC steel plate. To measure, the adhesion and thickness of the coating layers, a cross-cut tool (according to ASTM-D3359) and a thickness gauge (according to the ASTM-AMT15) were carried out respectively. It seems the spray paint refill equipment was functioning properly. This is due to the quality of the coating layers having good adhesion, shown by all specimens getting 5B classification (0% not peeled off). Moreover, an increase in the thinner composition is lead to a decrease in the coating thickness

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Pengaruh Suhu Pengeringan Elektroda E 7018 Terhadap Hasil Pengelasan Material A36

The better welding results are always a scientific challenge in welding engineering. This is to ensure the connection functions properly according to its designation. The main purpose of this study was to determine the effect of electrode drying temperature on the mechanical properties of ASTM A36 steel weld joint. This research was conducted at the Condet Welding Training Center and PT. Gamma Hepsi Condet. The tests carried out were visual tests, radiographs, and tensile tests. The results showed that the drying of the electrode E 7018 without an oven had a lot of welding defects on the inside in the form of porosity about 2 mm. The results showed that the highest tensile strength of 50.01 kgf/mm² was found in specimens using an electrode drying temperature of 230ºC

Rationale, design, and baseline characteristics in Evaluation of LIXisenatide in Acute Coronary Syndrome, a long-term cardiovascular end point trial of lixisenatide versus placebo

Background: Cardiovascular (CV) disease is the leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (T2DM). Furthermore, patients with T2DM and acute coronary syndrome (ACS) have a particularly high risk of CV events. The glucagonlike peptide 1 receptor agonist, lixisenatide, improves glycemia, but its effects on CV events have not been thoroughly evaluated. Methods: ELIXA (www.clinicaltrials.gov no. NCT01147250) is a randomized, double-blind, placebo-controlled, parallelgroup, multicenter study of lixisenatide in patients with T2DM and a recent ACS event. The primary aim is to evaluate the effects of lixisenatide on CV morbidity and mortality in a population at high CV risk. The primary efficacy end point is a composite of time to CV death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for unstable angina. Data are systematically collected for safety outcomes, including hypoglycemia, pancreatitis, and malignancy. Results: Enrollment began in July 2010 and ended in August 2013; 6,068 patients from 49 countries were randomized. Of these, 69% are men and 75% are white; at baseline, the mean ± SD age was 60.3 ± 9.7 years, body mass index was 30.2 ± 5.7 kg/m2, and duration of T2DM was 9.3±8.2 years. The qualifying ACS wasamyocardial infarctionin83% and unstableangina in 17%. The study will continue until the positive adjudication of the protocol-specified number of primary CV events. Conclusion: ELIXA will be the first trial to report the safety and efficacy of a glucagon-like peptide 1 receptor agonist in people with T2DM and high CV event risk. © 2015 Elsevier Inc. All rights reserved