Conventional gasoline engines suffer from low performance and NOx emissions.  Controlled auto-ignition (CAI), sometimes referred to as homogeneous charge compression ignition (HCCI), is a promising concept to solve such problems. CAI has the potential to improve spark ignition (SI) engine fuel economy while at the same time solving the trade-off of NOx-soot emissions found in compression ignition (CI) engines. The CAI engine can reach a fuel economy comparable to that of a conventional diesel engine with ultra-low NOx and negligible soot emissions. However, controlling auto-ignition remains the biggest difficulty that hinders the implementation of CAI as a commercial engine. Research towards a cleaner and more efficient engine is driven by the progressively stringent emission regulation imposed worldwide. Therefore, the CAI was developed to meet the emissions target while maintaining engine performance. CAI works on the principle of lean mixture and auto-ignition. To obtain CAI combustion, the temperatures in the cylinder must be sufficient to initiate auto-ignition. Without the use of a spark plug or injector, the CAI suffers from a direct control mechanism to start the combustion. The most practical approach to controlling the initiation of auto-ignition in CAI is diluting the intake charge by either trapping the residual gas or recirculating the exhaust gas. Both approaches enable the engine to achieve CAI combustion without requiring significant modifications to control the onset of CAI combustion phase.

Abstract— This study explored experimentally the use of vertical and horisontal position of cylindrical drying chamber dryer Fluidzed Deep against temperature distribution, humidity, drying rate, decreasing grain water level, and decreasing grain mass. The method used in this research is design and experiment. This machine uses a burning furnace as a heat source,sengon/ albasia wood as fuel, flat plate type heat exchanger, cyclone to convert wet vapor to dry vapor, filter to dry vapor cleaner, cylindrical drying chamber, blower to blow air, and Jig to support all components. This experiment was carried out three times for the drying chamber in a vertical position, and three times for the drying chamber in a horisontal position. In one drying time, it takes about 270 minutes. In the drying chamber measured temperature and humidity at 12 points of measurement. The results showed that the horisontal cylinder drying chamber produced higher temperature distribution than the vertical cylinder drying chamber, but the temperature distribution was less even, the vertical cylinder dryer produced lower humidity than the horisontal cylinder drying chamber, but resulted in higher deviation than the horisontal cylinder dryer. Drying rate, decrease in grain water content, average grain decrease on average faster than horisontal cylinder. The process of reducing the grain moisture content from about 20% bb to a moisture content of dry milled grains of about 14% bb occurred for 270 minutes or about 4, 5 hours. Keyword: Experimental design; Fluized deep dryer; dryer efficiency

Engineered wood must undergo a long period of drying process before it is ready to be used. Therefore, a new heat exchanger technology must be invented to dry the engineered wood more effectively. The quality of the engineered wood is one of the factors influencing the production process. This research was conducted to identify the optimal temperature for drying engineered wood using a cross-flow flat-plate heat exchanger with unmixed fluid arrangement and to determine the heat exchanger’s most efficient number of passes. This research was conducted using the numerical method (CFD simulation) and the Ansys Fluent software. In this research, the viscosity, density, and pressure constant were determined to be at 1 atm. We used air as fluid medium with a mass density of 1,228 kg/m3, air thermal conductivity of 0.0286 W/m.K, fluid viscosity of 2,0349.10-5 N.s/m2, steam mass density of 0.689 kg/m3, and thermal conductivity of 0.0370 W/m.K. Results showed that, in order to increase the air temperature in the drying chamber, heat energy of 69566.01 kJ/s must flow into the flat-plate heat exchanger. Further calculations show that the heat exchanger’s effectiveness (ϵ) was 25% and that the average temperature in the heat exchanger on the air side and the gas side was 68.63 oC and 172.5 oC, respectively.

Penelitian ini bertujuan untuk mengkaji performa produksi ayam broiler yang diberi betterzym dengan level berbeda. Rancangan yang digunakan dalam penelitian ini adalah rancangan acak lengkap (RAL)yang terdiri atas 4 perlakuan dan masing-masing perlakuan terdiri atas 5 ulangan sehingga terdapat 20 satuan percobaan, setiap ulangan terdiri dari 5 ekor ayam. Perlakuan yang digunakan adalah : P0 = Ransum control, P1 = Ransum + Betterzym 0,040%, P2 = Ransum + Betterzym 0,045%, P3 = Ransum + Betterzym 0,050%. Parameter yang dapat diamati dalam penelitian ini adalah konsumsi pakan, pertambahan bobot badan, dan konversi pakan. Hasil penelitian menujukkan bahwa ayam broiler yang diberi betterzym pada level 0,040% sampai 0,050% belum memberikan efek yang signifikan terhadap konsumsi pakan, pertambahan bobot badan dan konversi pakan.

The processed wood industry urgently needs a dryer to improve the quality of its production. One of the important components in a dryer is a heat exchanger. To support a durable heat transfer process, a superior material is needed. The aim of the study was to analyze the effectiveness of the application of cross-flow flat plate heat exchangers to be used in wood dryers and compare the materials used and simulate heat transfer on cross-flow flat plate heat exchangers using Computational Fluid Dynamic simulations. The results showed that there was a variation in the temperature out of dry air and gas on the flat plate heat exchanger and copper material had a better heat delivery by reaching the temperature out of dry air and gas on the flat plate type heat exchanger of successive cross flow and.   overall heat transfer coefficient value and the effectiveness value of the heat exchanger of the heat transfer characteristics that occur with the cross-flow flat plate type heat exchanger in copper material of 251.74725 W/K and 0.25.

Sampah plastik polypropylene yang diperoses secara pirolisis merupakan proses dekomposisi senyawa organik yang terdapat dalam plastik melalui proses pemanasan dengan sedikit atau tanpa keikutsertaan oksigen.  Senyawa hidrokarbon rantai panjang diubah menjadi rantai pendek. Suhu rata-rata plastik menjadi bahan bakar minyak 120 oC sampai 135oC dioptimasi dengan reaktor semi batch dan kondensor type vertical dimana umpan 1,000 gram menghasilkan minyak 782 ml dan konsumsi bahan bakar 0.284 kg sampai 0.3 kg tanpa pemanasan awal dan 0.15 kg sampai 0.18 kg dengan pemanasan awal. Kadar oktan 67.3 sampai 78.6 untuk hasil minyak yang dicapai. Yield proses pirolisis dipengaruhi: Jenis plastik, kebersihan plastik dan area plastik yang dimasukkan kedalam reaktor, efek suhu dan laju pemanasan. Berdasarkan hasil pengujian kinerja alat pirolisis dengan menggunakan sampah plastik polypropylene yaitu panas yang hilang pada alat dapat dimanfaatkan sebagai pemanas awal untuk mengurangi pemakaian awal bahan bakar, yaitu berat bahan bakar LPG yang diperlukan dari 0,284 kg menjadi 0,172 kg, Plastik polypropylene dapat diolah menjadi bahan bakar minyak dengan metode destilasi vertikal dan hasil minyak setelah pengujian Lembaga yang berkompeten LEMIGAS mencapai angka oktan 78.6, Yield proses pirolisis dipengaruhi oleh jenis plastik dan kondisi plastik yang harus bersih, Minyak yang didapat mencapai 78.6 % dari kondensor 1 dan 2, Laju produksi destilasi minyak 22.46 gr/menit, Waktu pirolisis semakin lama, produk yang dihasilkan yieldnya semakin tinggi, Pressure drop -7bar yang rendah menyebabkan minyak hasil pirolisis keluar dari kondensor lebih lama dan kuantitasnya besar.

Solar energy is a combination of light and heat produced by the sun, where this energy is utilized by humans through solar collector technology consisting of PV modules to be converted into electrical energy. The development of PV module technology is carried out to improve its performance, where one of these technologies uses a reflecting mirror to increase the amount of sun radiation captured by the surface of the PV module. This research method uses performance analysis of the utilization of reflector mirrors added to the PV module system by using two different cases, among others are the use of two and four mirrors along the sides of the PV module. The results showed that the application of four reflective glass can direct the sun's radiation to the surface of the PV module with the amount of radiation intention doubled. This result is a kind of technology that gives us a good result to utilize it in building the solar power plant.

Heat exchanger is an equipment designed to exchange heat between two fluids by applying heat transfer by convection and conduction without mixing the two fluids. heat exchangers are used in the gold mining industry in the gold elution process stage with the type of alat penukar kalor pelat datar(PHE) UFX-42H to reheat the eluate (water) using glycol as the heating fluid. The PHE has a leak on the back base plate. This report aims to analyze the comparison of the effectiveness and LMTD of PHE between specification data and operational data at the time of leakage. The calculation off effectiveness requires the suhue, mass flow rate, and specific heat of the fluid. The results obtained were the effectiveness of the specification data is 0.83 and the mean of operational data is 0.71. The results of LMTD specification data is 23.91 and the mean of operational data is 28.1.