Algorithm Development to Predict the Dynamic Characteristic of a Multi Rotor System

Rotor systems have been widely used in mechanical applications in industry andeven in daily live equipments. The motion effects of the rotor in certain cases can cause discomfort to the user even can cause of failure to the system itself. Therefore the dynamic characteristic analysis of the system is very essential to be analysed in designing a rotor system. By the development of computer technology, the analysis can be straightforwardly performed through numeric method by utilizing existing computational software, i.e. MATLAB. Existing researchers have developed the algorithm to analyse the dynamiccharacteristic of Jeffcot rotor and dual rotor systems by using MATLAB. The objective of this research is to conduct further investigation in developing algorithm to predict the dynamic characteristic of a multi rotor system. The analysed rotor system consists of a rotor shaft and several disks. The analysis is conducted for a variation number of disk. The equation of motion of the system is derived based on the potential and kinetic energy of the system. Lagrange‟s equation is then applied to the equation of motion that it can be solvednumerically. Based on the equation of motion, a computational algorithm is then developed to determine the natural frequency of the rotor shaft which is the main objective of this research. The algorithm is developed and simulated in MATLAB. The simulation result is closed with theoretical analysis

The Use of Finite Element Method in Analysing the Dynamic Characteristic of a Rotor System

Vibration analysis is very essential to be considered in designing a rotor system. The failure in rotor system parts can be avoided by understanding the dynamic characteristic. The objective of this research is to investigate the dynamic characteristic of rotor systems by using finite element method. Finite element method is used to reveal the system characteristic which is derived from the kinetic and potential energy equations. Some models of rotor systems are analysed to understand the dynamic characteristic. The natural frequencies are obtained from the eigen values. The simulation is carried out with the distance of disk from the support as the variable. The result shows that the distance between the disk and the bearing affects the natural frequency of the system

Perancangan dan Pembuatan Dapur Peleburan Logam dengan Menggunakan Bahan Bakar Gas (LPG)

Foundry industry is very important in the development of both machinery and household products. Furnace is important utility in producing a product. Available furnaces in the market are very costly and difficult to obtain due to be imported from abroad. Responding these issues, in this study is designed and developed a furnace that is simple, easy to manufacture, portable and most importantly the price is low so that it is affordable for industrial-scale domestic foundry industry. The furnace is heated with LPG (Liquefied Petroleum Gas) as the gas is economical and obtainable. Refractory stones are used as a heat insulator to increase the temperature in the combustion chamber to reach 1,000 oC. The heat can be set via the setting of gas that goes into the combustion chamber so that it can be adapted for different types of material with a melting temperature below 1,000 oC. The type of metal melted in this research is aluminum. The test results showed that the furnace is able to melt 0.39 kg of aluminum in 30.15 minutes

Kaji Eksperimental Getaran Roda Gila pada Sepeda Statis

The use of flywheel as an energy storing device has been introduced in various mechanical systems. In this paper is discussed the use of it on a stationary bicycle. The flywheel technology is utilised on the bicycle to provide as well as distribute the load in cycling. The focus of the research is the affectivity of the flywheel usage considered from the vibration occurred. In this research, a new model of stationary bicycle is designed to have a reliable and comfortable stationary bicycle. Thus, the vibration caused by the flywheel is one of the concern that an experimental study has been conducted. Based on the experimental test it concluded that the vibration occurred is moderate that the design of the bicycle is acceptable for use

Experimental study the effect of diesel engine performance fuelled by waste tire oil- dexlite blends

It well known that tire as a waste from vihicles susch as passengger car, truck and trailller. Indonesia country has enough potensial of tire waste, it was produced of about 11 millions ton per years. This phenomena could be serious environmental problem because tire waste was difficult dissolve by environment. It is needs to solve this issue by convert the waste tire to oil fuels. The main focus of this research to evaluate the performance of diesel engine fuelled by waste tire oil-dexlite blends. The physicochemical properties such as viscosity, density, calorific value and cetane number the waste tire fuel and its blends with dexlite were analysed. The experimental methode to determine engine performance by using the CI engine with variation of speed from 1500 rpm to 2100 rpm and waste tire-dexlite blends ratios at 10% (WTO-10), 20% (WTO-20) and 30% (WTO-30) of waste tire oil (WTO) and dexlite were utilized as a fuels. The CI engine with variation of speed from 1500 rpm to 2100 rpm was selected in order to determine the engine performance. The experimental results showed that the blending of waste tire oil with dexlite from 10% to 30% can operate with CI engine without any engine modifications. The results of this study revealed that maximum power and SFC were found to be 2.3 kW and 0.48 kg/kWh, respectively. Moreover, at the engine speed of 1900 rpm and a fuel blend of WTO-10 were found that to be optimal values of power and thermal efficiency which is similarly by using dexlite as fuel

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Pengembangan Algoritma untuk Menganalisis Frekuensi Pribadi Poros dengan Rotor Ganda

Vibration analysis is very essential to be considered in designing a rotor shaft. By the development of computer technology, the vibration analysis of the rotor shaft can be easily performed by numeric method. The objective of this research is to develop an algorithm to determine the natural frequency of a rotor shaft of a dual rotor system. The equation of motion of the system is derived from the kinetic and potential energy. By applying Lagrange’s equation and converting them into matrix form, the equations can be easily solved numerically. Through this approximation is developed computer program. The model is a rotor system built of a rotor shaft and two disks. The rotor shaft is numerically divided into several line elements. From the global matrices of the elements, it is resolved the eigen values of the system which are then converted into the natural frequencies. The validation of the program result with analytical calculation shows a very close result

Kaji Eksperimental Perpindahan Panas Pada Lemari Penyimpan Darah Portable Dengan Memanfaatkan Efek Peltier

The process of blood storage is the important part in maintaining the blood quality. After it is donated by the donor, the blood will be stored in a storage cabinet until it is needed by the patient. One of the common ways to preserve and maintain the chemical and structural changes of the blood is to store it in a storage area that has a temperature of between 1-6 °C. Blood storage cabinets that already exist this days, use the vapour compression cycle which is only suitable for the storage of large capacity and is not portable if there is blood demand in remote areas. To answer these problems, in this research will be designed and manufactured portable blood storage cabinet by the size of 30 cm x 30 cm x 30 cm. The heat in the storage is discharged to the air by using a heat pump which works using thermoelectric cooler (Peltier effect). The Peltier effect occurs when two metals or semi-conductors of different materials are connected and energized that there will be a difference in temperature. In order to test the feasibility of the blood storage cabinets technically, the heat transfer study is conducted. The experimental result shows that the expected temperature is achieved

Penggunaan Accelerometer dan Strain Gauge Sebagai Sensor Untuk Mendeteksi Kerusakan Pahat Potong

The damage of cutting effect the product a lot, thus reducing the quality and dimensional change of the product. This research aims to monitor damage of cutting tool throught the accelerometer and strain gauge sensors on the process of turning Rod hydraulic cylinder SAE 1045 using cutting carbide coated. The machining process is carried out by the variation of cutting parameters, depth of cut 0,5 and 1,0, feed rate o,5 and 0,7 mm/min, and constant cutting speed of 1300 rpm. This experiment is conducted on three cutting tool condition they are new, medium wearing (0,15 mm) and critical wearing (0,3 mm). The censors used are accelerometer and strain gauge which are placed in the holder. The result show that kurtosis, RMS and standard deviation parameters are influenced by the tooling condition. Have the relation toward the wearing change of tooling, this case is showed by the existence of progress from the new, medium and critical tooling test. As for amplitude strain gauge signal also showed a significant change when there is damage to the wearing tools. This showed that the bigger wearing happening the higher signal out going

Kaji eksperimental dan pemodelan numerik perpindahan panas pada lemari penyimpan darah portable dengan memanfaatkan efek peltier

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