Tresna P. Soemardi

The Effects of Plates Position in Vertical Casting Producing Thin Wall Ductile Iron

In the general rule of casting design the thickest part of the cast should be placed near to the ingate. This arrangement was meant to guarantee the completion of filling process. An unusual vertical casting design to produce plates with different thicknesses was established based on the idea that the heat from molten metal will always warm up its entire runner. In this design the thinnest plate is placed near to the ingate. The design was made for producing thin wall ductile iron. This research was conducted to see the effects of reverse thickness arrangement in casting design to the microstructure and mechanical properties of the plates. Plates produced by this design were compared to plates produced by the same design with general casting arrangement. Thicknesses of the plates produced in this casting were 1, 2, 3, 4, and 5 mm. The moulds used were made from furan sand. Beside experiment, casting design simulation with Z-Cast was also conducted to ensure the completion of filling process and to see the manner of solidification. Casting simulation showed that arrangement of plates gave different filling and solidification manners. Although there were some differences, the filling was successful for both arrangements of plates. Skin effect was found in both designs. Nodule counts and nodularity were higher in the new design while average nodule diameters were lower. The result gained in tensile and hardness test did not follow the correlations in the characteristic of graphite. Mechanical properties showed that position of plate, ignoring the thickness, influence tensile strength and hardness.

Electroencephalography (EEG) for detecting acute ischemic stroke

Currently, the study of EEG for detecting circulatory blood disorders in the brain, including strokes are being widely investigated. EEGs are widely used to diagnose epilepsy, seizures, Alzheimers disease, cerebral dysfunctions and degenerative diseases of the brain. The aim of this study was to develop a software tool to enhance the available EEG in type C hospital for diagnosing stroke. Patients were examined using EEG and CT-Scan within 48 hours after the onset. The EEG signals were analyzed using spectral analysis of each channel, Welch analysis for detecting the decrement of frequency and BSI (brain symmetry index) for left and right hemisphere of the brain and other standards clinical examination. These signals were compared with the CT-scan to get abnormalities of the signals. There were some irregularities of the EEG signals in comparisons with CT-scan. All patients were examined stroke based on CT-scan. However, there were examined as normal, epileptic form, and stroke based on EEG readings. All of the BSI calculations were above the healthy subjects (0.042 ±0.005), which indicated that all subject were Acute Ischemic Stroke. While for some readings according to the conventional EEG indicated that 20% of the subjects were normal or within normal conditions. These were consistent with the ratios of power densities that all subjects were abnormal. Even these results were consistence with the CT Scans but they should be extended to more subjects in order to get a better conclusions.

Development of the Third Darrieus Blade of Sultan Wind Turbine for Low Wind Speed

Use of NACA 0012 at the Sultan Wind Turbine prototype provide value coefficient power turbine at wind speed 5.5 m / s by 0017 , wind speed 6.1 m / s at 0.015 , wind speed 7.7 m / s at 0.016 , wind speed 6.5 m / s for 0018 and wind speed 6.2 m / s by 0017 . Where the value of the highest efficiency obtained at a speed of 6.5 m / s at 0.018 . This result is not as expected to generate sufficient energy.The next development carried out investigations on some kind of airfoil, from investigations obtained by using Qblade software that NACA 6612 has a value of 1.78 CL at 15 degrees angle of attack is the largest of all the airfoil .In this research, NACA 6612 will be simulated with a variable chord length, angle of attack, and wind speed, of these three variables will be created which will map graphics 3d sliding value of the ratio of the 3 variables, this graph will give recommendations most optimum combination of variables to types are mapped wind speed throughout the year, to produce optimum power.Optimum combination of NACA 6612 with wind speed varied from 2-7 m/s is chord length 30 cm and angle of attack 7 degree.

Development of friction and wear full-scale testing for TKR prostheses with reliable low cost apparatus

Prostheses products must undergo simulation and physical testing, before clinical testing. Finite element method is a preliminary simulation for in vivo test. The method visualizes the magnitude of the compressive force and the critical location of the Total Knee Replacement (TKR) prostheses design. In vitro testing is classified as physical testing for prostheses product. The test is conducted to evaluate the potential failure of the product and the characteristics of the prostheses TKR material. Friction and wear testing are part of the in vivo test. Motion of knee joints, which results in the phenomena of extension and deflection in the femoral and tibia insert, is represented by friction and wear testing. Friction and wear tests aim to obtain an approximate lifetime in normal and extreme load patterns as characterized by the shape of the friction surface area. The lifetime estimation requires friction and wear full-scale testing equipments for TKR prostheses products. These are necessary in obtaining ...

Performance Improvement of Baggage Handling System in the Soekarno-Hatta International Airport

Growing number of passenger in the world resulted congestion problem in the airport. Many airports try to improve the performance of the service by company program related to passenger satisfaction. To develop the company program, management of airport should know performance of existing system. In this research, we measure and compare the performance of the existing system and new system of airport departure terminal of Soekarno-Hatta International Airport (SHIA). Discrete-event simulation method was developed to measure the system. ProModel simulator software, from ProModel Corporation, was utilized to simulate the existing system and new system of Departure Terminal in the Airport. To measure the performance, authors focus on some indicators, i.e., passengers processing time, passengers waiting time, and utilization of each station. The authors make some scenarios based on the increasing of passengers 4.9 % in 2015, 18.9 % in 2020, 17.7 % in 2025, and 1.5 % in 2030. There is a significant difference in 2020–2025 in amount of 25 % in order to the passengers’ average time. Therefore, the new system will have better performance.

The accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data

Prostheses are a derivative of biomedical products that have important things, which are: a design, size and bio compatible material. To produce optimum prostheses, safe and comfortable use, it would require design a model that fits the size of the patient’s anatomy. In this paper describes the accuracy of solid model and rapid prototype of prostheses in comparison to the digital CT image data. Where the main parameters used as the reference measurement is digital CT image data. The data were analyzed using a statistical method to get the standard deviation of the comparison parameters of the data obtained, so that it can be known how the accuracy of the measurement results of each data.

Tomography Observation of Fiber Reinforced Composites after Fatigue Testing

This work presented an experimental study to observe the inside conditions and damage appearances of fiber reinforced composites material by non destructive testing (NDT) method. In order to achieve this, an open hole specimen of unidirectional glass fiber composite (GFRP) and discontinuous carbon fiber composite (DCFC) had been using as the specimen test under tensile fatigue loading and observed using post failure monitoring techniques of NDT namely computed tomography (CT) scan. The results shown that the tomography observation based on segmentation method of gray value gives a good detection on early damage appearances before final failure of GFRP and DCFC after tensile fatigue loading conditions.

Performance Improvement Using Simulation and Line Balancing; Application in Departure Terminal at Airport

Evaluation of service at the airport is important for the passenger satisfaction. Based on the evaluation results, the management of the airport can decide what can be done to improve the system. In this research, we have evaluated and improved the performance of the departure terminal system at Soekarno-Hatta International Airport using simulation and line balancing methods. There are several steps in the research: evaluating the performance of existing system using simulation method: optimizing the system using line balancing and simulation methods: and analysing the results of the optimization process. The results show that the performance of the optimization process can decrease passenger processing and waiting time. We conclude that line balancing and simulation methods can be utilized to optimize the system of the departure terminal at the airport.

Application of Semi Automatic Model of Product Complexity Index Calculation by Identification and Recognition of Geometric Features Information

It is a phenomenon that an experience mechanical/ design engineer with years of experience in mechanical parts design, still must to improve the knowledge about process design. This phenomenon will be different with other fields but common in process design because design is continuous process. The automotive industry is expected to be one of the driving factors for economic growth in Indonesia in 2025. It is shown by research firm (Frost & Sullivan) that estimates this years car sales in Indonesia will rise moderately by 6.5% from a year earlier to 948,500 units and the real car sales in Indonesia rose to 43% in April 2012. Development should be increased because the government provides to industrial facilities that conduct research, development and innovation. Therefore the design process until production is expected to be rapid and immediate product can be enjoyed by society. To speed up the production process, the design process should be faster, and account how the next process that is the production. This research useds the form of the usual features carried with three machining processes are widely used in the world of mechanical component industries. The processes are turning (around 24.9% of machining process), milling (around 20.2% of machining process) and drilling (around 28.2% of machining process). The overall mean of the three processes around 73.3% of the portion of the machining process (survey conducted by PERA).