572 research outputs found
Biodiesel production from high FFA rubber seed oil using waste cockles
A two-step heterogeneous catalyzed process of high free fatty acids (FFA) rubber seed oil was conducted to produce biodiesel in lab scale. Acid esterification process was first used to reduced the high FFA rubber seed oil from 78.9% to below 1%. The low cost cockle shell was utilized as a source of CaO heterogeneous catalyst by calcination process and its effect on transesterification process was studied. The optimum yield of 88.06% was obtained for the final product of biodiesel under optimal conditions of 16:1 molar ratio of methanol to oil, 9% catalyst weight percentage with 3 hours reaction time. All fuel properties were analysed according to the ASTM D 6751 standard and found within the requirements
The tribological characteristics of the cactus and mineral oil blends using four-ball tribotester
The oil derived from vegetables has been seen as an alternative to mineral oils for lubricants because of certain inherent technical properties, renewable source and their abilities to biodegrade. Vegetable oil is known to have a high viscosity index with a higher lubricity value compared to mineral oil. Despite its potentiality as a candidate alternative, vegetable oil has several limitations. It has a low wear resistance, and it is highly sensitive to temperatures with tribological characteristics. The majority of technical solutions, including additivation, chemical alterations, and blending, are being proposed as means of overcoming the listed limitations. This study seeks to investigate the characteristics of cactus oil with respect to its use as a bio-lubricant as well as the characteristics of environmentally friendly vegetable oil when they are mixed with mineral oils as alternative oil for petroleum, using the four-ball tribotester. The volumetric blending ratio was varied (20% to 80%) and these blends were performed at 1200 rpm, for one hour, with 40 kg of load at a temperature of 75ºC (ASTM D4172-B) standard. According to the results, it was found that the lowest wear scar diameter was 431.23μm, which was identified in the blend of 20% cactus oil with 80% mineral oil which symbolized by (CC20%), compared to that of neat cactus oil at 669.16 μm and mineral oil at 546.46 μm.In addition, the result also indicates that a 80% addition of cactus oil, the coefficient of friction tends to decrease compared to the values of neat cactus oil. Finally, it is concluded, the blends of cactus oil with commercial lubricant oil have better performance compared to commercial lubricant oil or neat cactus oil
Heterogeneous transesterification of rubber seed oil biodiesel production
An experimental investigation was conducted to explore the effects of using waste cockle shells as a heterogeneous catalyst on the transesterification process of very high free fatty acid (FFA) rubber seeds oil with methanol. The waste cockle was calcined at 900°C for 4 hours and was employed as a source of calcium oxide (CaO). SEM, XRD and XRF were adopted to analyze the catalyst characterization. The process variables namely oil molar ratio, catalyst concentration and reaction time were optimized using response surface methodology (RSM) based on central composite design (CCD) method. The optimum yield of 88.06% was obtained for the final product of biodiesel with optimal conditions was obtained as: molar ratio of methanol to oil of around 15.57:1, 9% catalyst weight percentage with 2.81 hours reaction time. All the fuel properties were analyzed according to the ASTM D6751 and EN-14214 standards in terms of viscosity, acid value, density and flash point
Co-combustion modeling of rice husk and plastic bag as energy source in Indonesia
This study was conducted to obtain a model combustion characteristics of rice husk and plastic bags as a energy source. The characteristics modeling using Autodesk Mechanical Desktop, Gambit, and Ansys - Fluent software. Maximum temperature of gas in the grate bed was obtained of about 1,710 K, in the furnace of about 1,670 K, and the average temperature in the furnace of about 1,086 K. The flue gas CO2, CO, and H2O in the furnace was obtained maximum of about 0.336% (3,360 ppm), 0.305% (3,050 ppm), and 0.132% (1,320 ppm), respectively. It was concluded that the co-combustion characteristics model of RH90 + PB10 produces temperature that meets the needs of a trap on the boiler and flue gas produces a small that is safe for the environment. Thus, it can be the basis for the development of utilization as fuel in the power plant
Securing industrial control system environments: the missing piece
Cyberattacks on industrial control systems (ICSs) are no longer matters of anticipation. These systems are continually subject to malicious attacks without much resistance. Network breaches, data theft, denial of service, and command and control functions are examples of common attacks on ICSs. Despite available security solutions, safety, security, resilience, and performance require both private public sectors to step-up strategies to address increasing security concerns on ICSs. This paper reviews the ICS security risk landscape, including current security solution strategies in order to determine the gaps and limitations for effective mitigation. Notable issues point to a greater emphasis on technology security while discounting people and processes attributes. This is clearly incongruent with; emerging security risk trends, the biased security strategy of focusing more on supervisory control and data acquisition systems, and the emergence of more sector-specific solutions as against generic security solutions. Better solutions need to include approaches that follow similar patterns as the problem trend. These include security measures that are evolutionary by design in response to security risk dynamics. Solutions that recognize and include; people, process and technology security enhancement into asingle system, and addressing all three-entity vulnerabilities can provide a better solution for ICS environments
Faktor yang Mempengaruhi Penurunan Angka Kesembuhan TB di Kabupaten Banjar Tahun 2013
Penelitian ini bertujuan untuk menganalisis faktor karakteristik individu, perilaku, faktor peran pengawas minum obat (PMO), kondisi rumah penderita, tingkat kepatuhan penderita TB paru terhadap kesembuhan penyakit TB paru dalam pengobatan di Puskesmas Astambul Kabupaten Banjar Provinsi Kalimantan Selatan. Penelitian dengan pendekatan cross sectional ini menggunakan uji statistik menghitung Odd Ratio (OR). Hasil penelitian menunjukkan bahwa kesembuhan penyakit TB Paru lebih kecil 1,6 kali pada umur muda dibandingkan dengan umur tua, pada responden dengan ventilasi tidak memenuhi syarat kesehatan 1,3 kali lebih kecil dibandingkan dengan responden dengan ventilasi rumahnya yang memenuhi syarat kesehatan, pada responden dengan pencahayaan tidak memenuhi syarat kesehatan 1,3 kali lebih kecil dibandingkan dengan responden dengan pencahayaan yang memenuhi syarat kesehatan. Responden dengan pengetahuan kurang 6,7 kali untuk tidak sembuh dibandingkan dengan kesembuhan TB Paru pada responden dengan pengetahuan baik (OR=6,750), serta kesembuhan penyakit TB Paru pada responden dengan tindakan kurang 4,3 kali untuk tidak sembuh dibandingkan dengan kesembuhan TB Paru pada responden dengan tindakan baik (OR=4,333). Peningkatan keaktifan Pengawas Minum Obat pun perlu diupayakan untuk meningkatkan kepatuhan minum obat dan kesembuhan TB Paru pada masyarakat
A bottleneck investigation at escalator entry at the Brisbane central train station
© 2016 ATRF, Commonwealth of Australia. All rights reserved. Escalators are an essential for passenger’s movements through multi-level rail station concourse environments. Despite the access benefits that escalators provide, they can make travel time longer and pose some challenges when bottlenecks appear at entry. Studying the passenger behaviour of bottlenecks at escalator entrances is essential for planning, designing and control of engineering transportation systems. In this paper we investigate passenger route choice behaviour while approaching an escalator-stair infrastructure set at Brisbane Central train station. A model of an escalator entry bottleneck is formulated. The developed model can explain the queuing characteristics of the bottlenecks and can be readily used to predict congested state occurrence at escalator entry bottleneck. Accurate prediction of bottlenecks occurring around escalators and the estimation of escalator capacity are obtained based on real field data collected from Brisbane Central train station. Results have provided significant insights and computational tools for understanding many features of escalator bottlenecks. Remarkably, escalator capacity at bottleneck points affects the duration and severity of the congested period
Analysis of Safe Behavior on Shipyard Workers at PT Dok & Perkapalan Kodja Bahari (Persero) Cabang Palembang in Period of October 2012
Background : PT Dok & Perkapalan Kodja Bahari (Persero) Cabang Palembang is a shipyard company specialized in making and reparation of ships. Within its activity, there were so many hazards came from characteristic of process or material of production which can cause accident, however based on preliminary survey which has been conducted showed that the shipyard workers did not wear personal protective equipment (PPE) when doing their activity so that there were an indication that they has not applied safe behavior as well. JURNAL ILMU KESEHATAN MASYARAKATMethod : This study was an analytical survey study with cross sectional approach. The Population was shipyard workers of PT Dok & Perkapalan Kodja Bahari (Persero) Cabang Palembang in period of October 2012 with samples as a number of total individual (50 person). Independent variables were knowledge, attitude, act, availability of means and facilities, safety regulations, role of co-workers, role of supervisor, communication and training, while dependent variable was safe behavior. The research data were analyzed quantitatively by method of univariate and bivariate with chi square analysis using SPSS program . Result : The result showed from total of nine variables, there are six variables that associated with safe behavior of the shipyard workers, that are knowledge (OR = 3,9; p-value = 0,023), attitude (OR = 0,2; p-value = 0,033), act (OR = 0,1; p-value = 0,011), role of co-workers (OR = 5,4; p-value = 0,031), communication (OR = 6,1; p-value = 0,019) and training (OR = 4,6, p-value = 0,014). Conclusion : To reduce the risk of accident of the shipyard workers, PT Dok & Perkapalan Kodja Bahari (Persero) Cabang Palembang needs to improve its workers' safe behavior by noticing the variables associated with safe behavior of the workers, especially those still considered not good enough, that are knowledge, attitude, act and training. It is suggested for PT Dok & Perkapalan Kodja Bahari (Persero) Cabang Palembang to apply punishment and reward system, increase communication, conduct frequent trainings, involve the workers' participation in various OHS program and also apply Behavior Based Safety (BBS) approach
Advancement in the production of activated carbon from biomass using microwave heating
An overview of recent advancement in the production of activated carbon (AC) from biomass using microwave heating is presented. The use of microwave heating method for the thermal conversion of biomass to useful products has been on the increase in the last decade because it offers fast and uniform heating, and a higher level of automation. The effects of process parameters (microwave power and radiation time, agent flow rate in physical activation and impregnation ratio in chemical activation) on the properties and adsorption capacity of the AC are reviewed. From the results reported in the literature, it can be seen that the influence of the preparation parameters on the adsorption capacity of the prepared AC followed the same pattern. In the physical activation process, microwave power and radiation time have more pronounce effects on the properties of the AC than the activation agent flow rate. Furthermore, the properties of the AC were found to be at their best when the process parameters are at the optimum values wether individually or collectively, and further increase in the process value beyond optimum value resulted in decrease in their adsorption capacity
Emission and performance characteristics of waste cooking oil biodiesel blends in a single direct injection diesel engine
The use of Waste Cooking Oil (WCO) as feedstock, and microwave heating technology are favored to reduce the cost of biodiesel. In order to identify the effect of using biodiesel from WCO Methyl Ester (WCOME) blends on diesel engine emissions and performance, WCOME blends were tested in a single-cylinder Direct Injection (DI) diesel engine at a constant speed of 2500 rpm and with five loads. For comparison, commercial diesel fuel, Petron Diesel Max (PDM), and biodiesel mixture from palm oil (POME) were also used. The performance and emission test results of the five test fuels: PDM, BP10, BP20, BW10, and BW20 were then compared with simulation results created by using GT-Power software. The experimental results indicated that using POME and WCOME blends led to increments in Brake Specific Fuel Consumption (BSFC) of up to 5.9% and reduction in Brake Thermal Efficiency (BTE) of up to 29.3% compare to PDM. These biodiesel blends also increased nitrogen oxide emissions and decreased carbon dioxide, carbon monoxide and hydrocarbon emissions for all engine loads at a constant speed of 2500 rpm. The experimental testing of the cylinder peak pressure demonstrates significant increase with the increase of engine load for the four test fuels. All the simulation graphs show similar trends
- …