MAKARA Journal of Technology
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AN AGRI-FOOD SUPPLY CHAIN MODEL TO ENHANCE THE BUSINESS SKILLS OF SMALL-SCALE FARMERS USING CORPORATE SOCIAL RESPONSIBILITY
Get PDFIn general, small-scale vegetable farmers experience problems in improving the safety and quality of vegetables for supplying high-class consumers in modern retailers. Farmer Group and/or Cooperative (FGC) should be able to assist its members to meet the relevant provisions of modern retail on product specifications, delivery terms, and internal business requirements. This study proposed an agri-food supply chain (ASC) model that involves the corporate social responsibility (CSR) activities to enhance the business skills of the FGC as supplier of modern retailer. Multi-objective optimization programming is developed to determine the amount and timing of supply, level of farmers training skills, quality improvement target, and the CSR total cost. The results show that the proposed model can be used to determine the priority of programs in order to empower farmers' groups as modern retail suppliers.Keywords: agri-food supply chain, business skills, corporate social responsibility, supplier of modern retaile
OPTIMIZING FERMENTATION MEDIUM TO PRODUCE CYCLOSPORIN A USING RESPONSE SURFACE METHODOLOGY
Get PDFResponse surface methodology (RSM) is a three factorial model which illustrates the relationship between one or more independent variables. RSM can be used to optimize the fermentation medium for the production of Cyclosporin A from the isolate Tolypocladium inflatum. The optimal point of the response surface area is predicted by using a second-degree polynomial model and applying the statistic model obtained from the central composite design (CCD). The results of optimizing the fermentation medium for Cyclopsorin using the three independent variables of glucose, casein, and KH2PO4 show that all three of the independent variables affect the production of Cyclosporin A. There is a positive interaction between the independent variables of glucose and casein, however, there is no visible interaction between glucose with KH2PO4 and casein with KH2PO4. By using the mathematical model the total optimum result obtained is 1230.5 mg L-1, glucose concentrate 28.5 g L-1, KH2PO4 concentrate 0.74 gL-1, and casein concentrate 9.8 g L-1. Laboratory validation shows that Cyclosporin A productivity is 1197.285 mg L-1. There is a value difference of 2.7% between the expected productivity of Cyclosporin A using the mathematical model and the actual production in laboratory tests.Keywords: Cyclosporin A, optimization, response surface methodolog
EFFECT OF METHANOL INDUCTION AND INCUBATION TIME ON EXPRESSION OF HUMAN ERYTHROPOIETIN IN METHYLOTROPIC YEAST Pichia pastoris
Get PDFErythropoietin (EPO) is a glycoprotein hormone consists of 165 amino acids and has molecular mass of 30,400 Daltons. The large quantities of these hormone required to satisfy clinical demand are currently met by recombinant expression in mammalian cell, namely chinese hamster ovary (CHO). Pichia pastoris has become popular yeast based protein production systems to substitute mammalian expression systems. P. pastoris is capable to use methanol as sole carbon and energy source. In this study, recombinant human EPO (rhEPO) protein obtained by expressing the hEPO gene in methylotropic yeast P. pastoris, strain X33. The present work was carried out to study the optimal methanol concentration for induction and the incubation time to obtain rhEPO protein. To perform this study, the transformed P. pastoris was induced with various concentrations of methanol (0%, 0.5%, 1%, 2.5%, 5%, 10%, and 20%) and incubation times (0 hours, 24 hours, 48 hours, 72 hours, 96 hours, 120 hours, and 144 hours). The results demonstrate that the highest protein expression level occurred at concentration of 2.5% methanol induction, while the optimal incubation time was at 48 hrs.Keywords: hEPO, methanol, Pichia pastoris, Western blo
FUEL SAVING STRATEGY IN SPARK IGNITION ENGINE USING FUZZY LOGIC ENGINE TORQUE CONTROL
Get PDFIn the case of injection gasoline engine, or better known as spark ignition engines, an effort to improve engine performance as well as to reduce fuel consumption is a fairly complex problem. Generally, engine performance improvement efforts will lead to increase in fuel consumption. However, this problem can be solved by implementing engine torque control based on intelligent regulation such as the fuzzy logic inference system. In this study, fuzzy logic engine torque regulation is used to control the throttle position entered by the driver to achieve optimal engine torque. An engine torque vs. throttle position and engine speed mapping for vehicles with economical function is used to build this control process regulation. From the simulation result, it can be concluded that this control strategy is very effective to reduce fuel consumption and simultaneously to optimize the engine performance.Keywords: engine torque control, fuzzy logic, spark ignition engin
PINEAPPLE LIQUID WASTE AS NATA DE PINA RAW MATERIAL
Get PDFThis research aims to study the quantity, quality, ecological and economic feasibility of nata de pina production (NP) from pineapple liquid waste (PLW). The design of the study employs complete random design (CRD) with three treatments: PLW without nutrients addition (A), PLW nutrients addition (B), and PLW stored for six months with nutrients addition (C). The nata de pina’s production factors measured were weight, thickness, fiber content, color, brightness, and residual waste. The highest weight was reached in treatment B (899 grams), followed by treatment A (616.4 grams), and C (477.8 grams). The thickness of NP of the height and low as in treatment B (1.58 cm) followed by treatment A (1.24 cm) and C (0.88 cm), respectively. The highest fiber content was found in treatment C (9.3%) followed by treatment B (7.6%) and A (6.9%), respectively. The fiber content, along with color quality and brightness fit with food standards. The production of NP may reduce the volume of the PLW from 46.2% to 89.1% (p= 0.001). Based on the standard value of biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS) below to the required threshold except pH. The production of NP is economically feasible to 4.7 BC ratio. The overal manufacture of nata de pina from PLW produces better and feasible product ecologically andKeywords: bioremediation, Nata de pina, pineapple liquid waste (PLW
MODELING OF A NEW STRUCTURE OF PRECISION AIR CONDITIONING SYSTEM USING SECONDARY CONDENSER FOR RH REGULATION
Get PDFA dynamic mathematical model for a new structure of precision air conditioning (PAC) has been developed. The proposed PAC uses an additional secondary condenser for relative humidity regulation compared to a basic refrigeration system. The work mechanism for this system and a vapour-compression cycle process of the system are illustrated using psychrometric chart and pressure-enthalpy diagram. A non-linear system model is derived based on the conservation of mass and energy balance principles and then linearized at steady state operating point for developing a 8th-order state space model suited for multivariable controller design. The quality of linearized model is analyzed in terms of transient response, controllability, observability, and interaction between input-output variables. The developed model is verified through simulation showing its ability for imitating the nonlinear behavior and the interaction of input-output variables.Keywords: modeling, multivariable model, precision air conditioning, vapour-compression cycl
TOLERANCE LIMIT FOR TRUCKS WITH EXCESS LOAD IN TRANSPORT REGULATION IN INDONESIA
Get PDFReliability of a road is mandatory since damaged will impede the traffic. Destruction is caused by various factors; one of the most important factors is excess load. Overload may give the load of each axle of a vehicle exceeds the determined standard. This condition occurs in trucks exceeding the load limit. In designing the structure of a road based on the method of Directorate General of Highways Ministry of Public Works of the Republic of Indonesia, axle load calculated in equivalent-number, or known as equivalent axle load (EAL), of 8.16 tons of standard axle. Total equivalent-number over the service life is defined as cumulative equivalent standard axle load (CESA). Due to traffic volume exceeding the volume forecast or, in other words there is an excessive load of traffic, it will make CESA achieved faster than planned. This excessive load in Indonesia, however, has been considered as a factor of environmental condition, so there is a need to introduce a correction factor for EAL as high as 20-25% in the process of designing flexible and rigid pavement so as to reduce early damage.Keywords: equivalent axle, excessive load, pavement, truck
CIRCULARLY POLARIZED MICROSTRIP ARRAY ANTENNA FOR GROUND SEGMENT IN QUASI-ZENITH SATELLITE SYSTEM
Get PDFIn satellite communication system, antenna plays an important role. Therefore, the antenna must meet some requirements, such as high gain, circular polarization, and good directivity. In this paper, a four element linear array triangular patch microstrip antenna with cross slot is designed to be used for Quasi-Zenith satellite system. A simulation study as well as experimental study was carried out. The simulation showed that the 3 dB axial ratio bandwidth of 87 MHz (2.569-2.656 GHz) is achieved while the measured results showed 96 MHz (2.556-2.652 GHz). The linear array of 4 element antenna has a gain of 13.73 dB and maximum radiation pattern at 40° and -40°. Simulation and experiment results show that this antenna has met the characteristic requirements of Quasi-Zenith satellite. Keywords: circular polarization, cross slot, microstrip antena array, Quasi-Zenith satellit
CORROSION RATE OF CARBON STEEL FOR FLOWLINE AND PIPELINE AS TRANSMISSION PIPE IN NATURAL GAS PRODUCTION WITH CO2 CONTENT
Get PDFThe purpose of this research is to investigate the corrosion rate of carbon steel as flowline and pipeline in natural gas production with CO2 content. The influence of variety of conditions that represent the actual conditions in practice such as CO2 partial pressure and solution composition, particularly NaCl percentage were performed. Research conducted by polarization test and simulation methods using PREDICTTM software. The result of this research is used to illustrate the level of corrosion rate of typical carbon steel i.e. API 5L X-52 occurred in natural gas pipelines due to the effect of dissolved CO2. From the experiments obtained that corrosion rate of steel in environments containing CO2 ranged between 15-28 mpy. This high corrosion rate observed could severely damage natural gas transmission flowline and pipeline. The result of this research is the first step, as an input for prevention efforts, to prevent leakage of flowline and pipeline due to corrosion of CO2 which appropriate with the lifetime that has been designed.Keywords: carbon steel, CO2, corrosion rate, flowline, pipelin
EARTHQUAKE DAMAGE INTENSITY RELATIONSHIP FOR RESIDENTIAL HOUSES IN WEST SUMATRA
Get PDFThe Sumatra 30 September 2009 earthquake has damaged hundred thousand buildings in West Sumatra Province. The earthquake is located in 100 km offshore of Padang City, the Capital City of the province. Survey has been conducted to assess the damage of the building in few days after the earthquake. In this survey, the damage of buildings are categorised into 3 level that are heavily, moderate and slightly damages. This paper explores the level damage of building and then the intensity of the shaking in the affected area. Then based on the coordinate of every building location, the buildings are scattered in a map together with the intensity level. The relationship between the damage level and intensity for West Sumatra then is developed. This special damage-intensity relation is very important to be used for predicting the damage level due to a specified earthquake. The damage level is needed by The Government to develop an emergency and reconstruction budget plan for earthquake disaster in future.Keywords: earthquake, damage assessment, earthquake intensit