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The purpose of this research was to discover the various reasons of failures and appropriate repair options for the line ducting cleaning unit system at PT Pusri Palembang's NPK-1 production facility. The main cause of the failures was determined to be a deterioration of the ducting line material caused by corrosion on the inner side of the ducting pipe composed of SS400 carbon steel. We made investigation including an analysis of the thickness of the damaged ducting pipe, as well as a visual check. The investigation showed that the corrosion caused an average drop in pipe wall thickness of up to 70%, according to the findings. The fixed load superimposed on the ducting pipe and the carrying capacity of the piping affect ducting strength, but corrosion on the inner surface of the pipe, caused by direct contact with corrosive and hygroscopic process dust, reduces ducting wall strength against axial and lateral loads. Failure of this ducting pipe caused losses and unscheduled shutdowns of production process, and increased the repair costs also could increase the risk of human accidents. The suggestion as this investigation results is to upgrade the ducting pipe materials to the more corrosion-resistant materials, such as stainless-steel grade SS304. Other suggestion should be taken is also regularly to inspect the ducting cleanness for the internal of ducting and control the dust flow rate through the scrubbing system. As conclusion, the suggestions given are to mitigate the risk of corrosion impact by maintaini­­­­­­ng ducting strength within the minimizing ducting system failures and ensuring the NPK plant's operation reliability.

The purpose of this research is to calculate the effect of the screw extruder angle on the results of 3-dimensional printer filaments that are printed using a single screw extrusion machine. The machine parameters used in this study were: pull speed 16 rpm, extrusion speed 28 rpm, extrusion mold diameter of 2 mm, and temperature of 180oC. The material used is recycled HDPE plastic. While the tilt angle of the screw in the research conducted by providing 5 variants of the angle of inclination (0o, 10o, 15o, 20o, 25o) where the diameter of the screw shaft used is the same. Data analysis was carried out using a simple linear regression method. Where the results obtained were: 1) the smallest filament diameter was 0.9 mm when using a screw with an angle of 0o, and 2) the highest diameter was 1.86 mm when using a screw with an angle of 25º. The conclusion obtained is that the tilt angle of the helical screw affects the results of recycled HDPE plastic extrusions, where the effect of the screw angle tilt is directly proportional to the filament diameter. In other words, with the addition of the tilt angle of the screw, the diameter of the resulting filament will also increase. In addition, based on the results of measuring the diameter of the filament, the conclusion that can be drawn is that with the increase in the diameter of the extrusion result, the outflow obtained will also be greater.

Batok Kelapa merupakan salah satu bahan yang dapat diproses dalam pembuatan asap cair. Proses produksi arang dari batok kelapa secara tradisional yaitu dengan metode drum klin berpotensi menimbulkan polusi udara. Prototipe penyulingan asap cair berbasis microkontroller bertujuan untuk membantu para pembuat arang guna untuk meminimalisisr potensi polusi udara pada para petani tersebut serta menambah pendapatan selain dari proses penjualan arang. Hasil pengujian prototipe diharapkan dapat meningkatan hasil produksi asap cair dibandingkan dengan menggunakan air yang bersuhu ± 29°C, dimana dengan menggunakan refrigerasi dimana suhu air akan diturunkan sampai 15°C yang basis pengontrolannya secara mictrokontoller yang di program dengan menggunakan aplikasi arduino. Berdasarkan hasil pengujian prototipe mesin penyuling asap cair di Desa Desa Tanjung Lago Kabupaten Banyuasin diperoleh produk berupa asap cair tanpa sistem refrijerasi sebanyak 203 ml dan penyulingan dengan menggunakan sistem refrijerasi sebanyak 375 ml asap cair.

The microcontroller-based liquid smoke distillation device aims to help farmers who produce liquid smoke where liquid smoke is used to freeze rubber latex in order to increase the results of making liquid smoke by using refrigeration technology applications whose control base uses Arduino hardware which is programmed using the matlab application so that has a positive impact in the marketing process of the sales of smoke looking for which previously used water with a temperature of ± 29°C. The process of designing tools takes advantage of CAD software while manufacturing uses drilling machines, hand grinding machines, electric welding machines, and hand tools. After manufacturing, the prototype of the tool will be tested in the laboratory to see the work function of the tool.

Recently, liquid smoke is widely used for various needs, both for food purposes and for freezing rubber latex. Liquid smoke began to grow due to the large demand, also using biomass / waste as a base material. Immediate production results are needed by the condensation process. The application of the refrigeration system guides the temperature of the air which is used as a cooling medium in the condensation process during the process of making liquid smoke. This study uses coconut shell as raw material for pyrolysis, and there are 4 temperature variations that are applied in the liquid smoke production process. First without a refrigeration system, the application of a refrigeration system with temperature variations of 22 ° C, 18 ° C and the last one is 15 ° C. The data is taken every 30 minutes for 6 hours. Based on the research results, it was found that the maximum production results using the refrigeration system at an air temperature of 15 ° C, resulted in 375 ml of liquid smoke.

Penelitian ini berupa rancang bangun sebuah prototipe mini pengkondisian udara tipe water cooled water serta melalukan pengujian prototipe dengan menggunakan variable berupa temperatur nyaman kabin yang dicapai 22,8oC~26,7oC. Dalam pengujian prototype bertujuan mengkaji kinerja hasil rancang bangun berbasis mikrokontroler Arduino Uno untuk pengontrolan temperatur kabin yaitu sensor temperatur DS18B20 dan tanpa menggunakan Arduino Uno. Penelitian ini dilakukan selama satu jam dengan lima waktu pengujian yaitu pada menit 0 ke 10, menit 11 ke 20, menit 21 ke 30, menit 31 ke 40, menit 41 ke 50 dan menit 51 ke 60. Hasil penelitian menunjukan pengunaan mikrokontroler Arduino menghasilkan konsumsi rata-rata daya kompresor berkisar 247watt~264watt dan ketika temperatur minimum evaporator sebesar 8oC tercapai, maka konsumsi daya kompresor mengalami penurunan antara 70,22% sampai dengan 93,29%. Hal yang sama juga terjadi ketika temperatur maksimum evaporator tercapai (20oC), konsumsi daya kompresor juga mengalami penurunan diantara 59,77% hingga 72,02%. Sedangkan hasil pengujian tanpa menggunakan mikrokontroler Arduino konsumsi daya kompresor selalu cenderung konstan pada menit 10 hingga menit ke 60, dimana rata-rata konsumsi daya kompresor berurutan berkisar 267watt~ 275watt untuk tiap capaian temperatur evaporator. Dalam hasil pengujian berbasis mikrokontroler Arduino memberikan penghematan konsumsi energi listrik berupa daya kompresor sebesar 14,65 watt untuk tiap 10 menit pengujian. Hasil penelitian juga diketahui pengontrolan temperatur berbasis mikrokontroler perlu dilakukan agar koefisieb kinerja (coefficient of performance) mesin dapat dijaga konstan serta salah satu langkah agar kompresor tidak bekerja secara terus-menerus (continuously) pada saat temperatur kabin tercapai, dalam hal ini dapat menjaga umur pemakaian kompresor.

Nodular Cast Iron have ductile properties when added with elements of magnesium or cerium and this will cause the ductility range of 10-20% increase, hardness and low tensile strength, easy to be formed compared to alloy steel (alloy steel) or high carbon steel (high carbon steel) and the price is relatively cheap, making this material widely used as a basic material (raw material) for the manufacture of a product. To get hard properties on the surface, this material can be carried out a surface hardness process, so that the product can be functioned according to its application. Way that can be done to increase surface hardness as well as low carbon steel strength is by adding carbon elements to the steel which is commonly known as carburizing. The carburizing process is carried out on a muffle furnace specifically heat treatment that is easy to operate in setting the heating temperature, heating speed and holding time. In this research, it is designed and carried out on low carbon steel using carburization media with a ratio of 70% activated carbon and 30%, calcium carbonate (CaCO3) at 900°C heating temperature, holding time variations of 2, 3 and 4 hours respectively, then proceed with the process cooling or double quenching. The results of this study are expected to obtain a product made with cast iron nodular material, so it can the economic value of the product.

This paper presents a design of digital stethoscope that is modified using DSK TMS320C6416T. This modified stethoscope is proposed for helping the doctor to make a true decision and the same perception on the symptoms of someone’s disease. Using the conventional stethoscope usually gives drawback, such as the doctors usually makes misinterpretation on the auscultation. The reason is because of the errors that occur due to the difference on the sensitivity of the ear and the experiences of the doctor. This research offers a DSK TMS 320C6416T as an instrumentation system for identification and analysis on the lung sound. The modified design of the digital stethoscope that is proposed in this research gives benefit to the users because it provides the result in the form of the signals that can be monitored in the PC. The results of this designed stethoscope showed the interpretation of graphs in the form of the spectrogram and scalogram which will help the simplification on the analysis of lung sounds as well as to minimize or avoid the limitations of hearing problems in the process of auscultation. The method used in lung sound analysis in this research includes Fourier Transformation that is then developed into a Short-Time Fourier transform (STFT) and continued to the Wavelet Transform. Based on the test data for normal lung sounds, it was found that the working frequency range was 90 to 1265 Hz. The adventitious sounds were found with frequency range from 60 to 1980 Hz. In this research, it was also found that the lung sounds were at the frequency range from 90 to 1015 Hz for direct measurement to patients.

Electrical energy is needed by the citizen of Indonesia including in Palembang City. Palembang is growth rapidly, in contrast there is still citizen who has not enjoyed the electricity especially who is living in Sukamulya Village, Sematang Borang Sub-ditrict. Constructing a Micro Hydro Powerplant is an effort to facilitate an electircity to the area which has not been covered by PT. PLN. Howefer before constructing a hydro power plant , a study should be conducted in order to estimate the potency of electrical power which could be generated. Therefore the authors have collected some primary datas such as dimension of river, velocity of water and geographical condition. These datas is used to calculate the potency of energy, either in form of potential or kinetic energy. Based on the on-site observation, all locations have no enough elevation difference. Nevertheles the onlyform of energy which can be converted into electrical energy is kinetic energy, which determined by the river flow velocity. The fastest river flow is found in Location of B amounting 0.35 m/s. By optimazing the dimension of turbine and considering the efficiency of transmision and generator, it predicts Turbine, located in Location B, can generat e electrical energy with the maximum power of 66.26 Watt. Based on the results, the electrical power potency in all locations are low and did not fullfill the requirements. The power can be increased by levelling up the elevation of the upstream. It can be done by constructing a dam which integrated with irrigation system. Nevertheles it need a future study in order to predict the impacts. Keywords: : Micro Hydro Powerplant, Energy Potency, River Flow, Palembang city

Tujuan penelitian ini untuk mendapatkan model pemprediksian performansi aerodinamika dari turbin angin Darrieus dengan metode multiple streamtube, memvalidasi model yang didapat dengan model yang sudah ada, dan menggunakan model hasil validasi untuk memprediksi dan menghasilkan data baru untuk turbin dengan skala, ukuran, bentuk, jenis sudu, kecepatan angin yang berbeda. Dua bentuk sudu rotor turbin juga diadopsi dan dua kumpulan data dari dua jenis sudu yang berbeda dipergunakan dalam penelitian ini untuk melihat seberapa besar perbedaan hasilnya. Torsi dan koefisien daya yang dibangkitkan meningkat seiring penurunan koefisien drag yang merupakan fungsi dari bilangan Reynold. Sudu jenis NACA 0012 jauh lebih baik perfomansinya bila dilihat dari koefisien dayanya.