Multilayer plastic waste continues to increase due to the ever-growing consumption and needs of the global citizen and is one of the most challenging types of waste to recycling because of its nature. The accumulation and indiscriminate... more
Multilayer plastic waste continues to increase due to the ever-growing consumption and needs of the global citizen and is one of the most challenging types of waste to recycling because of its nature. The accumulation and indiscriminate disposal of waste can pose a potential risk of environmental problems. A solution that can be implemented is to mix bitumen and waste polymer as asphalt manufacturing. Despite its advancement in research, many potential parameters are still to be discovered to achieve optimal results. Through cold plasma treatment, a surface treatment may occur at the multilayer polypropylene that causes the change from hydrophobic to hydrophilic properties. Treating the polymer with cold plasma will provide good hydrophilic properties without changing the overall chemical and thermal properties of the sample. This will result in an alternative aggregate for the bitumen for asphalt manufacturing. Bitumen coupled with the addition of plastic still provides an optimal ...
The development of computer aided design (CAE) technology, especially casting simulation software (Magmasoft v5), can be utilized maximally as a tool to verify the design of castings that have been made to be able to meet the elements of... more
The development of computer aided design (CAE) technology, especially casting simulation software (Magmasoft v5), can be utilized maximally as a tool to verify the design of castings that have been made to be able to meet the elements of QCD (quality, cost, delivery) and compete in the market. This study aims to obtain an optimal ESV housing casting design by reviewing and modifying the casting design in terms of both quality and economics. The process of design optimization with casting simulation is an important step in the design and development of casting products to improve casting yield and casting quality. The optimal design of castings is obtained by improving the design through pouring system using bottom pouring and optimizing the riser design. The results of this study obtained Design # 2 as a design choice of pouring system because it can improve the quality of casting products. Design # 2 optimized again into Design # 4 as the optimum design and able to increase the yield casting by 5.11% from the previous design (Design # 2). The result of techno economic analysis shows that by allocating 4% budget for design cost can contribute to decrease of production cost of foundry ESV housing up to 54,95%.
Design optimization casting emergency stop valve steam turbine, has been done with casting simulation using Magmasoft v5 software. By simulation, some casting design parameters are changed to get more optimal results. Optimization of the... more
Design optimization casting emergency stop valve steam turbine, has been done with casting simulation using Magmasoft v5 software. By simulation, some casting design parameters are changed to get more optimal results. Optimization of the design of castings in this study, obtained by improving the design through changes in pouring system using bottom pouring and optimization of riser design. The result of four design casting simulation ESV housing versus filling velocity, solidification, and porosity have the same trend of location defect that is in the flange and middle body valve connection area. However quality of the simulation results, in design # 4 has a better quality of casting results based on the color gradation seen in the range of 80-90%. Although, there is still a potential defect in critical areas that have low castability. This results can be used as input for the further casting improvement and NDT inspector guidance.
This paper is interested to study power system stability in smart grid power system using wind characteristic in south of Yogyakarta, Indonesia. To overcome the intermittent of wind characteristics, this paper presents adaptive robust... more
This paper is interested to study power system stability in smart grid power system using wind characteristic in south of Yogyakarta, Indonesia. To overcome the intermittent of wind characteristics, this paper presents adaptive robust control design to enhance power system stabilization. The online identification system is used in this research, which updated whenever the estimated model mismatch exceeds predetermined bounds. Then genetic algorithm (GA) is applied to re-tune parameters controller based on the estimated model. The structure of controller is proportional integral (PI) controller due to the most applicable in industry, simple structure, low cost and high reliability. Robustness of controller is guaranteed by taking system uncertainties into consideration. The performance of the proposed controller has been carried out in a hybrid wind-diesel power system in comparison with previous work controller. Simulation results confirm that damping effect of the proposed controllers are much better that of the conventional controllers against various operating.
This paper is interested to study power system stability in smart grid power system using wind characteristic in south of Yogyakarta, Indonesia. To overcome the intermittent of wind characteristics, this paper presents adaptive robust... more
This paper is interested to study power system stability in smart grid power system using wind characteristic in south of Yogyakarta, Indonesia. To overcome the intermittent of wind characteristics, this paper presents adaptive robust control design to enhance power system stabilization. The online identification system is used in this research, which updated whenever the estimated model mismatch exceeds predetermined bounds. Then genetic algorithm (GA) is applied to re-tune parameters controller based on the estimated model. The structure of controller is proportional integral (PI) controller due to the most applicable in industry, simple structure, low cost and high reliability. Robustness of controller is guaranteed by taking system uncertainties into consideration. The performance of the proposed controller has been carried out in a hybrid wind-diesel power system in comparison with previous work controller. Simulation results confirm that damping effect of the proposed controll...
Microalgae perform oxygenic photosynthesis and are capable of taking up a large amount of CO2, using an inducible CO2 concentrating mechanism (CCM), and fixing CO2 into higher compounds. These characteristics make the microalgae... more
Microalgae perform oxygenic photosynthesis and are capable of taking up a large amount of CO2, using an inducible CO2 concentrating mechanism (CCM), and fixing CO2 into higher compounds. These characteristics make the microalgae potentially useful for removal and utilization of CO2 emitted from industrial plants and, generally, the usage of photosynthetic microorganisms has increased and significantly improved as a solution for CO2 emissions. In this light and based on previous research using Anabaena cylindrica IAM M1 and Spirulina platensis IAM M 135, enhancement was sought for CO2 fixation and biomass production by Chlorella vulgaris Buitenzorg by increasing the photon flux density concurrent with increases in culture biomass during the cellular growth phase and was compared to cultures of Chlorella grown at optimal constant illumination, with all cultures grown using Bennick basal medium, 29°C, and a flow of 1.0 atm. 10% CO2 enriched air delivered to three in serial photobioreactors of 0.200 dm3 capacity each. The results showed that increasing illumination during culture increased biomass production of Chlorella by ∼60% as well as increased CO2 fixation ability by ∼7.0%. It was also demonstrated that the non-competitive inhibition of [HCO3−] as a carbon source significantly affected the cultivation in both the increasing and constant photon flux density regimes.
Aluminium AC4B alloy is widely used in automotive industries for various components. However, when this alloy is used to produce motorcycle cylinder head by Low Pressure Die Casting (LPDC) process, high reject rate was often found due to... more
Aluminium AC4B alloy is widely used in automotive industries for various components. However, when this alloy is used to produce motorcycle cylinder head by Low Pressure Die Casting (LPDC) process, high reject rate was often found due to shrinkage, porosity and misrun. Addition of grain refiner and modifier is an alternative for this problem, through the control of solidification process that results in grain refining and microstructure modification. This study was aimed to investigate the effect of combination of 0.02 wt. % Sr modifier with variation of Ti grain refiner on the characteristics of AC4B alloy and the reject rate of cylinder head components. The Ti grain refiner was varied 0.063, 0.083 and 0.108 wt. % Ti and added at the holding furnace prior to LPDC process. A series of test was conducted including hardness test from the thin and thick regions of the part, tensile test, fluidity test, vacuum test as well as observation of microstructure by using optical microscope and...
