Experimental modal analysis of vehicle exhaust system to determine hanger location using root mean square value

Vibration of exhaust system due to the engine operation and the condition of the road surface which is transferable to the body through the hanger affects the noise, vibration and harshness performance of the vehicle, and the life time of the hangers. In order to solve this problem of the automobile exhaust system, experimental modal analysis was carried out by utilizing a sample exhaust system of passenger car as a research object within the frequency of interest. LMS Test. Lab was used to perform modal analysis. This study estimated the dynamic characteristics of the exhaust system such as natural frequencies and mode shapes. Using frequency response function at every measuring point, root mean square value (RMS) of vibrating energy was calculated to select hanger location of exhaust system where the RMS value is comparatively small. Experimental modal analysis is an efficient tool to study and estimate the dynamic properties of the exhaust system, and calculating RMS value is also an easy method to find hanger location of the exhaust system utilizing frequency response function

Experimental verification of parameters in automobile crankshaft modelling for vibration analysis

In the interest of utilized more stable automobile components at high speed for reduction the vibration of mechanical system, dynamic characteristics analysis plays a vital role in complex mechanical parts. This paper introduces a clarified approach on statistical investigation and modal analysis methodology to study, predict and accurate crankshaft natural frequencies by using design of experiment (DOE). In this research, first, simulation had been done with MSC Nastran/ Patran to find out the natural frequencies in each mode shape of crankshaft as well as the verification with experiment was carried out. In order to less inaccuracy, numerous simplified crankshaft models were created by using these as input and DOE was established to acquire precise parameters of optimized crankshaft design as the second phase. This method can be further used for the optimizing the structural parameters and would provide some value basis to qualitative measure of parameters and determination of optimized structure. In Conclusion, modal verification accuracy between experimental and simulation has improved

XRD and SEM Analysis, and Semiconductor Type Determination of TiO2 for Dye-sensitized Solar Cell

Titanium dioxide (TiO2) is a wide band-gap n-type semiconductor. Anatase TiO2 is the most common structure used in high performance dye-sensitized solar cell (DSSC). Nanoporous TiO2 serves double-duty as an electron acceptor and a scaffold to hold large numbers of dye molecules in DSSC. The porosity of TiO2 is a key feature as it has roughly a thousand times greater a surface area than the equivalent flat area. In this work, TiO2 crystallite size (43.55 nm) has been calculated by using XRD data, and the morphology and the grain-size of TiO2 (average grain size of 0.2 mm ~ 0.3 mm) with different solvents have been also studied by SEM

Temperature effect on dynamic characteristics and power flow of thin structures

Thin plates are being used in many engineering applications. However, thin plate-like structures face vibration problems and are exposed to high temperature in the different operational conditions. These conditions can cause degradation, and seriously affect the structural integrity, safety, and stability of the structure. Hence, it is extremely important to identify the dynamic characteristics and vibration power flow of the thin structure at different temperatures that indicates the transmission path, position of vibration sources, and sinks. This study examined the potential changes in the dynamic characteristics and vibration power flow of the thin structure at different temperatures. In the first step, experimental and numerical studies of dynamic characteristics and vibration power flow for thin plate were conducted. The thin plate was modelled in Patran software, and modal analysis was performed using MSC Nastran software. Then the experimental modal analysis was conducted to validate the results of the numerical analysis. In the second step, the effects of temperature changes on the dynamic characteristics and vibrational power flow were investigated. A climate chamber room was used to investigate the temperature effect on the dynamic characteristics and power flow. Finally, vehicle exhaust system, actual complex structure, was used for actual life application of vibration power flow at different temperatures. Based on the results, the visualization of vibration power flow and transmission paths were generated at its first four natural frequencies. The changes of vibration power flow of the plate and the exhaust system at different temperatures were generated. The data from both experiment and simulation show a good agreement. The high temperature shifts the natural frequencies to lower frequencies. At 90℃, the first and second modes shifted about 3 Hz, and the third and fourth modes shifted about 5 Hz, lower than those at the normal temperature. The finding indicates the higher the temperature, the lower the frequency shifted. At higher mode, the power flow pattern changed at a certain temperature. In addition, the temperature effect on the dynamic characteristics of the exhaust system is not significant at the lower modes. At the higher mode, the natural frequency is shifted to about 2 Hz when the temperature reaches 270℃. Due to the hanger isolators, the vibration power of the exhaust system reduced overall 19%. The maximum total powers were at 180℃ of the exhaust system (without hanger) and 150℃ of the exhaust system (with hanger). The results showed that the boundary conditions of the exhaust system could lower the temperature at which the maximum power flow occurs. In sum, the findings on the effect of temperature on dynamic characteristics and vibration power flow are useful to those concerned with minimizing vibration level in engineering components to consider for their design criteria or maintenance process

Predicting On-road Traffic Congestion from Public Transport GPS Data

This paper predicts traffic congestion of urban road network by building machine learning models using public transport GPSdata. The bus GPS data are collected over 18 months started in September 2017 and ended in January 2019. After the data cleaning and data processing are carried out, time series data analysis is performed on these data. Travel Speed Estimation andTraffic Jam Prediction Model are two major components of this work. Firstly, road network structure and GPS data sets are inputted to the Travel Speed Estimation Model to get estimated travel speed for every road segment in uniform time windows of aday. The next step is to set up Traffic Congestion Prediction Model from estimated average travel speed and current GPS datafrom the buses. Decision Trees, Random Forest Classifiers and ExtraTree Classifiers algorithms have been successfully appliedand validated with K-Fold cross validation yielding high prediction accuracy to a specific bus route in Yangon, Myanmar

Assessing Elite Capture in “Engaging Women and Men Farmers in Participatory Research and Extension” Project: A Case Study in Magway Township

The study was carried out to assess the existence of elite capture in the Australian Centre for Inter-national Agricultural Research (ACIAR) projected villages. The survey was conducted in three projected villages (Pho Lay Lone, Nat Kan and Aung Myay Kone), Magway Township in June 2017. The data on household livelihoods were collected from 40 households (20 projected households selected by the ACIAR project with predetermined criteria and 20 non-projected households selected randomly) from each of three projected villages to assess their original human, natural, financial, social and physical cap-itals. It was found that almost all of the natural, social and physical capitals of the projected households were higher than those of the non-projected households in Pho Lay Lone and Nat Kan villages. In com-parison the status of human and financial capitals of the projected households was superior to those of the non-projected households in Nat Kan village. It indicated that the project have chosen the households whose livelihood were better than those of the remaining households in Pho Lay Lone and Nat Kan vil-lages. Therefore, elite seemed to capture the project in Pho Lay Lone and Nat Kan villages. In Aung Myay Kone village, most livelihood assets under human, natural, financial, social and physical capitals were not significantly different between the projected and non-projected households. Therefore, elite capture could not be observed in the selection of project households in Aung Myay Kone village. It indi-cated that smallholders had little chance to get the benefits of the project in Pho Lay Lone and Nat Kan villages while the benefit of the project could cover the whole community in Aung Myay Kone village. Therefore, it can be suggested that there should be a proper analysis on the livelihoods of farm house-holds in the target areas before choosing the projected participants to prevent the elite capture

Pre-operative pseudothrombocytopenia: terrifying but innocuous

An isolated thrombocytopenia was found in a 47-year old man during pre-operative&nbsp;work-up for his closed radial bone fracture on left forearm after a fall. His platelet count&nbsp;was as low as 14 x 103/&mu;L, but there was no active bleeding and past history of bleeding&nbsp;disorder. The clue to true diagnosis started from careful blood film examination - platelet&nbsp;clumps in blood film. Repeat full blood count tests were requested not only with the usual&nbsp;anticoagulant EDTA (Ethylene diamine tetra-acetic acid) but also with heparin as well as with&nbsp;citrate. EDTA-dependent pseudothrombocytopenia was diagnosed which can be confused&nbsp;with other life-threatening platelet disorders. The operation was successfully done without&nbsp;unusual bleeding.</p

Transfusion-Associated Graft-Versus-Host Disease in Two Patients at Yangon General Hospital

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare complication&nbsp;of blood transfusion. Two male patients admitted to the Department of Clinical Haematology,&nbsp;Yangon General Hospital (YGH) diagnosed to have TA-GVHD in 2011 and in 2016 are presented. Both of the patients received blood donation from close relatives where&nbsp;neither leukoreduction nor irradiation was done. Both patients had fever, skin rashes,gastrointestinal symptoms, raised liver enzymes and pancytopenia. Skin biopsies of both patients showed characteristic histological changes. Unlike graft-versus-host disease that&nbsp;occurred after haemopoeitic stem cell transplantation, TA-GVHD involves the recipient&rsquo;s&nbsp;bone marrow leading to bone marrow aplasia</p

Hyperhemolysis with hemoglobin H disease

Hyperhemolysis syndrome is one of serious and potentially life-threatening complications of red blood cell transfusion, and is well described in sickle cell disease as well as in thalassaemias and other anaemias. It also is a great diagnostic and management challenge to laboratory scientists and attending physician taking care of patients with such kinds of diseases. A Myanmar patient with hemoglobin H disease presenting with acute hyperhemolysis syndrome was diagnosed timely and successfully treated with intravenous immunoglobulin (IV Ig) and methylprednisolone. A high index of suspicion allowing early diagnosis and prompt management can save lives of patients with hyperhemolysis syndrome.</p