PENGARUH PENCAMPURAN BIOETHANOL SEBAGAI BAHAN BAKAR TERHADAP PERFORMA MESIN DAN EMISI GAS BUANG PADA MOTOR BENSIN EMPAT LANGKAH SATU SILINDER

Cadangan2energi2fosil2Indonesia yang2terbatas memicu2munculnya masalah2krisis BBM2di2Indonesia. Untuk mengatasi2masalah2kelangkaan bahan2bakar2beberapa2cara dapat2dilakukan2antara lain2dengan2pencampuran bahan2bakar2dan2bioethanol. Penggunaan2bioetanol merupakan salah2satu2upaya2pemanfaatan2sumber energi biomassa karena2bioetanoldmerupakan2salah satu2bahan bakarsalternatif yangdramahdlingkungan. Untuk itu penulisdmelakukandcampurandbahan bakargRONd88 dansbioethanol denganhpersentase variasigbahan bakar 100%gRONe88w(E0), 10%wbioetanol-90%wRON 88e(E10), 20%dbioetanol-80% RONd88 (E20) . Metodeepenelitian yang digunakanepada penelitianeinieadalah metodeeeksperimeneyangedilakukanedi laboratoriumemenggunakan motor bensineempatelangkah. Variasieputaran mesineyangedigunakan yaitue3000erpm, 4000erpm, 5000 rpm, 6000 rpm dane7000 rpm. Kemudiansmasing-masingscampuran bahansbakar diuji secaraebergantian melalui sepeda motoreyangedihubungkanepada dinamometeresasis dan exhauste gas analyzer. Berdasarkanehasil pengujian, penggunaanebioetanolesebagaiscampuran bahansbakar RON 88eterbukti mampuemeningkatkanedaya danetorsi sertaemereduksi emisiegas buang. Dari hasilepengujian menunjukkanebahwa, peningkatanedaya dan torsieterbaik saatemenggunakanebahan bakarecampuran RON 88edan bioetanole20% (E20) denganepersentase peningkatanetorsi sebesar 0.1 Nm (2.12%) danedaya maksimumesebesars0.01 kW (0.53%), sertaspemakaian bahan bakar menurunssebesar 0.001 ml/detik padasputaransmesin 3000 rpm hinggas5000 rpm. Dan penurunan pengujian emisi gassbuang penurunanskadar CO dansHC terbaik diperolehspada saatsmenggunakan bahanebakar campuran RON 88 danebioethanole20% (E20). penurunan kadar CO dan HC terbaik diperoleh pada saat menggunakan bahan bakar campuran RON 88 dan bioethanol 20% (E20). Kata Kunci: Bioethanol, Motor Bensin, Torsi, Konsumsi Bahan Bakar, Emisi Gas Buang.

Modern gold standard of cardiac output measurement – A simplified bedside measurement of individual oxygen uptake in the cath lab

Objectives Cardiac output (CO) measurements employing the direct Fick principle represent the gold standard in right-sided heart catheterization (RHC). The current widespread approach in hemodynamic workup however uses the indirect Fick principle with assumed values for oxygen uptake (VO2) leading to incorrect CO values in up to 25% of patients. We have tested a contemporary breath-by-breath gas analyzer that allows precise real-time measurements of VO2 with appropriate time and effort to serve the direct Fick principle. Methods By means of a small and mobile metabolic cart assembled with widely used components of a standard spiroergometer, we performed bedside measurements of individual VO2. In 33 unselected, consecutive patients with various indications for RHC we compared CO values derived from indirect vs. direct Fick calculations. Results In 28 of the 33 patients, VO2 measurements were completed with a plausible dataset within a median of 3.2 (interquartile range 2.8–6.2) min. In nine of the 28 patients, CO values based on measured VO2 values differed by more than 20% from CO calculations based on assumed VO2 values with value deviations scattering over a broad range in both directions (maximally +52% to minimally −46%). Conclusions The bedside measurement of VO2 for gold standard CO determination is technically feasible within a few min and can thus be easily included in any RHC protocol. As modern therapy for numerus indications demand a precise upfront measurement of hemodynamics, our method might help to correctly identify patients for costly therapies.

Dinamika fluks CO2 pada perkebunan kelapa sawit di lahan gambut

Fluks CO2 pada perkebunan kelapa sawit di lahan gambut bersifat dinamis secara temporal dan spasial, yang berhubungan dengan berbagai faktor lingkungan. Fluks ini dapat dibedakan menjadi fluks dari respirasi akar, dari dekomposisi serasah, dan dari bahan gambut. Penelitian ini bertujuan untuk menetapkan dinamika temporal dan spasial fluks CO2, kontribusi respirasi akar dan dekomposisi serasah terhadap fluks, serta hubungannya dengan faktor lingkungan pada perkebunan kelapa sawit di lahan gambut. Pengukuran fluks CO2 menggunakan infra red gas analyzer (IRGA) yang dilakukan di gawangan hidup, gawangan mati dan lahan semak belukar. Pengukuran fluks dilakukan secara berulang setiap tiga hingga empat hari selama hampir lima bulan. Hasil penelitian memperlihatkan adanya dinamika temporal dan spasial. Secara temporal, fluks CO2 pada perkebunan kelapa sawit dan semak belukar berada pada kisaran 2.9 – 11.1 dan 0.5 – 6.4 g C-CO2/m2/hari. Secara spasial, fluks CO2 pada perkebunan kelapa sawit dan semak belukar berada pada kisaran 4.8 – 8.8 dan 2.7 – 3.4 g C-CO2/m2/hari. Kontribusi perakaran tanaman kelapa sawit dan dekomposisi serasah terhadap fluks sebesar 48.4 dan 5.8%. Hasil ini semakin menegaskan bahwa perakaran tanaman berperan penting terhadap pelepasan karbon dari permukaan tanah.

PENGARUH ARANG KAYU ULIN SEBAGAI CATALYTIC CONVERTER TERHADAP EMISI GAS BUANG DAN KONSUMSI BAHAN BAKAR PADA MESIN TOYOTA KIJANG 5K

Catalytic Converter adalah pengubah (modifier) yang menggunakan media yang memiliki katalis, dimana media tersebut diharapkan dapat membantu atau mempercepat proses perubahan zat (reaksi kimia) sehingga gas seperti CO dapat dioksidasi menjadi CO2, media katalis kimia pada suhu tertentu, tanpa perubahan atau penggunaan oleh reaksi itu sendiri. Catalytic converter berbahan arang kayu ulin untuk emisi gas buang dan konsumsi bahan bakar. Jenis penelitian ini adalah penelitian eksperimen. Pengujian yang dilakukan pada penelitian ini ada 2 yaitu knalpot tanpa catalytic converter dan knalpot dengan catalytic converter berbahan arang kayu ulin dengan variasi rpm 1500, 2500, 3500. Pengujian emisi gas buang menggunakan alat yang disebut gas analyzer. Berdasarkan hasil penelitian dapat disimpulkan bahwa catalytic converter berbahan arang kayu ulin dengan diameter lubang 20 mm mampu mereduksi emisi CO dengan reduksi sebesar 52,23%, dan emisi HC lubang berdiameter 20 mm dengan jumlah 85,63. Catalytic Converter is a converter (modifier)that uses media that has a catalyst, where the media is expected to help or accelerate the process of changing substances (chemical reactions) so that gases such as CO can be oxidized to CO2, chemical catalyst media at a certain temperature, without change or use by the reaction itself. Catalytic converters made from ironwood charcoal to exhaust emissions and fuel consumption. This type of research is experimental research. There are 2 tests of this research, namely exhaust without catalytic converter and exhaust with catalytic converter made from ironwood charcoal with variations in rpm 1500, 2500, 3500. Examination of exhaust emissions using a device called a gas analyzer. Based on the results of the study it can be concluded that catalytic converters made from ironwood charcoal with a hole diameter of 20 mm were able to reduce CO emissions with a reduction of 52.23%, and HC emissions of a hole diameter of 20 mm with an amount of 85.63,

Review of an experiment to study the propane discharge in a closed production area

В статье представлены результаты экспериментальных исследований истечения пропана в различных направлениях в закрытом помещении. Рассматривался случай, когда источник истечения находился в багажнике автомобиля - имитация нахождения автомобиля с газомоторным топливом на станции технического обслуживания. Целью эксперимента являлось изучение механизма пространственного распространения газа в закрытом помещении для валидации математических моделей, используемых в программном комплексе ANSYS Fluent при моделировании поступления пропана в закрытое помещение. This scientific work describes a test conducted in a multidisciplinary test box on the testing training ground of the Orenburg branch of the All-Russian Research Institute for Fire Protection of EMERCOM of Russia. For the experiment there was built a room to simulate a service station (or parking box) for two cars. The frame was made of wooden bars and a plastic film was used to isolate the internal volume. The experimental installation consisted of a gas source with an internal diameter of 5 mm, located in the center of the room, and a system for gas supply and registration of experimental data from six gas analyzers SGOES-2 with a measurement range of pre-explosive concentrations from 0 to 100% of the lower concentration limit of flame propagation (NKPR) or a volume fraction from 0 to 1.7% with absolute ± 5% NKPR (in the range from 0 to 50% NKPR) and relative ± 10% NKPR (in the range from 50 to 100% NKPR) errors. In the center of the experimental room there was placed a car with the gas source in the trunk. All openings to the interior were insulated with plastic film and mounting foam. Natural cracks were left between the trunk lid and the body. The gas source is located in the trunk of the car and is directed towards the wide part of the trunk at an angle of 30 degrees relative to the floor (simulating the location of the gas cylinder used in cars). The gas analyzers were located along the wall, where the outflow is directed along the perimeter of the trunk, and one gas analyzer was located directly in the trunk behind the gas analyzer to control gas contamination. Propane has been released into the trunk with a constant flow rate of 2.8 m/h for 5 minutes. There were 8 test starts of the gas supply system (the flow vertically down), and then there were carried out 3 experiments per 3 series of tests in each. The purpose of the test was to study the mechanism of spatial gas propagation in an confined space for validation of mathematical models used in the ANSYS Fluent software package when modeling the propane intake into the confined space

The Effect of Temperature on Solvent Recycle Process using Stripping of CO2 from MDEA, Ethylene Glycol, and Water

Stripping is a process to separate dissolved gas in the saturated solvent to regenerate the absorption solvent. In this study, N2 gas was used to strip dissolved CO2 gas in MDEA, ethylene glycol, and water. The experiment was conducted with three variations of temperature, namely 28°C, 35°C, and 50°C, to determine the effect of solvent’s temperature entering the stripper column on the value of the mass transfer coefficient (Kla). The stripper effluent was connected to the KANE 457 Flue Gas Analyzer to measure the concentration of CO2. Data retrievals were carried out at the 0; 30; 60; 90; 120; 150; 180th second. The experimental results show the trend of mass transfer coefficient of CO2 (Kla) is higher with the increase of solvent’s temperature entering the stripper.

Inter-Day Reliability of Resting Metabolic Rate and Maximal Fat Oxidation during Exercise in Healthy Men Using the Ergostik Gas Analyzer

The attainment of high inter-day reliability is crucial to determine changes in resting metabolic rate (RMR), respiratory exchange ratio (RER), maximal fat oxidation during exercise (MFO) and the intensity that elicits MFO (Fatmax) after an intervention. This study aimed to analyze the inter-day reliability of RMR, RER, MFO and Fatmax in healthy adults using the Ergostik gas analyzer. Fourteen healthy men (age: 24.4 ± 5.0 years, maximum oxygen uptake (VO2max): 47.5 ± 11.9 mL/kg/min) participated in a repeated-measures study. The study consisted of two identical experimental trials (Day 1 and Day 2) in which the participants underwent an indirect calorimetry assessment at resting and during an incremental exercise test. Stoichiometric equations were used to calculate energy expenditure and substrate oxidation rates. There were no significant differences when comparing RMR (1999.3 ± 273.9 vs. 1955.7 ± 362.6 kcal/day, p = 0.389), RER (0.87 ± 0.05 vs. 0.89 ± 0.05, p = 0.143), MFO (0.32 ± 0.20 vs. 0.31 ± 0.20 g/min, p = 0.776) and Fatmax (45.0 ± 8.6 vs. 46.4 ± 8.4% VO2max, p = 0.435) values in Day 1 vs. Day 2. The inter-day coefficient of variation for RMR, RER, MFO and Fatmax were 4.85 ± 5.48%, 3.22 ± 3.14%, 7.78 ± 5.51%, and 6.51 ± 8.04%, respectively. In summary, the current results show a good inter-day reliability when RMR, RER, MFO and Fatmax are determined in healthy men using the Ergostik gas analyzer.

Evaluation NO2 Detection Using Low-Cost Folded Path Photometer

Nitrogen dioxide (NO2) contributes to several impacts both for human health and the environment. Periodical measurement of NO2 at industrial and residential areas needs comprehensive and reliable instrumentation; long-interference-free measures with minimum maintenance and re-calibration. DOAS can be used as a direct measurement technique based on specific absorption characteristics of NO2 follow Beer-Lambert law. This research applies a low-cost folded path photometer for measurement NO2 in air. Cheap tubular acrylic used as a detection cell with a 3D printed framework makes it compact, modular, and flexible. Evaluation of the DOAS conducted by instrument test responses using NO2 gas. The estimated LOD was ~ 1263 pb using 2 nm resolution of the spectrometer and 6-meter detection cell length. Deviation of the DOAS estimated to be 0.8% at high concentration and 2.85% at a low concentration based on DOAS calibration. An intercomparison between methods used to evaluate instrument performance to measure NO2 using emission from a motorcycle with coefficient correlation (R) 0.649 for paired DOAS-ASTM D1607 Griesz Saltzmann Method 0.846 for paired DOAS-Electrochemical Gas Analyzer. This significant correlation is caused by different respond time between paired methods, while it is still comparable for NO2 measurement.