Friction material (metal reinforcement) analysis of brake pad for light rail train system

Brake friction material is very important in braking system where they convert kinetic energy of moving vehicles to thermal energy by friction during braking process. The purpose of this research is to determine the optimal friction materials composition of brake pad for light rail train system. Currently all the component of the train system including brake pad is imported from overseas such as Germany. Hence, this research is use to find the new formulation of the mixture ratio that may replace or compete with the commercial available brake pad. Three different testing which are density and porosity test, shore hardness test and wear test were done in order to select which metal is the most suitable for railway application. Different composition were used, (Cu30%BaSO430%), (Cu25%BaSO435%), (Cu20%BaSO440%), (Steel30% BaSO430%), (Steel25% BaSO435%), (Steel20% BaSO440%), (Al30% BaSO430%), (Al25% BaSO435%), and (Al20% BaSO440%) this study to determine the optimal properties with lower wear rate. The selected material were mixed and compacted into desired mould with 5 tons of pressure. The compacted samples were sintered using two different temperatures which is 600oC and 800oC. Steel30% BaSO430% results in the optimal composition since the result shows the lowest porosity, highest SD reading of shore hardness and the lowest wear rate. The samples were analysed by using Scanning Electron Microscopy (SEM) with an Energy Dispersive Spectrometry (EDS) system to determine the morphology surface and overall composition of the samples. Comparing different sintering temperature, the sintered sample of 800oC shows lower wear rate than the sample sintered at 600oC. This is due to dense sample without crack showing by the samples sintered at 800oC than at 600oC

Multi - objective sliding mode control of active magnetic bearing system

Active Magnetic Bearing (AMB) system is known to inherit many nonlinearity effects due to its rotor dynamic motion and the electromagnetic actuators which make the system highly nonlinear, coupled and open-loop unstable. The major nonlinearities that are associated with AMB system are gyroscopic effect, rotor mass imbalance and nonlinear electromagnetics in which the gyroscopics and imbalance are dependent to the rotational speed of the rotor. In order to provide satisfactory system performance for a wide range of system condition, active control is thus essential. The main concern of the thesis is the modeling of the nonlinear AMB system and synthesizing a robust control method based on Sliding Mode Control (SMC) technique such that the system can achieve robust performance under various system nonlinearities. The model of the AMB system is developed based on the integration of the rotor and electromagnetic dynamics which forms nonlinear time varying state equations that represent a reasonably close description of the actual system. Based on the known bound of the system parameters and state variables, the model is restructured to become a class of uncertain system by using a deterministic approach. In formulating the control algorithm to control the system, SMC theory is adapted which involves the formulation of the sliding surface and the control law such that the state trajectories are driven to the stable sliding manifold. The surface design involves the transformation of the system into a special canonical representation such that the sliding motion can be characterized by a convex representation of the desired system performances. Optimal Linear Quadratic (LQ) characteristics and regional pole-clustering of the closed-loop poles are designed to be the objectives to be fulfilled in the surface design where the formulation is represented as a set of Linear Matrix Inequality optimization problem. For the control law design, a new continuous SMC controller is proposed in which asymptotic convergence of the system’s state trajectories in finite time is guaranteed. This is achieved by adapting the equivalent control approach with the exponential decaying boundary layer technique. The newly designed sliding surface and control law form the complete Multi-objective SMC (MO-SMC) and the proposed algorithm is applied into the nonlinear AMB in which the results show that robust system performance is achieved for various system conditions. The findings also demonstrate that the MO-SMC gives better system response than the reported ideal SMC (I-SMC) and continuous SMC (C-SMC)

Sectoral Linkages; Identifying the Key Growth Stimulating Sector of the Pakistan Economy

This paper investigates growth linkages among agriculture, industry and different segments of the service sector with a view to identifying the main growth stimulating sector with the highest level of backward and forward linkages in the economy. Time series data is used for the period 1971 to 2002. We estimate growth linkages through OLS regression analysis, also the Granger causality test is used to determine the direction of causality between growth of the different sectors of the economy for Pakistan. Our results suggest that the industrial sector plays an important role in determining the overall growth rate of the economy. The industrial GDP growth rate and service sector GDP growth rate both cause the growth rate of agricultural GDP. This verifies the neoclassical arguments that the higher productivity techniques in industry, (particularly in manufacturing) tend to spill over to agriculture, so encouraging convergent tendencies in sectoral productivity levels.Growth; Sectoral Linkages; Pakistan

Public / Private Investment Linkages: A Multivariate Cointegration Analysis

The link between public and private investment is investigated using annual data of the period from 1964–65 to 2004-05. The estimates based on structural cointegration approach indicate that both are cointegrated and public investment crowds in private investment. The study then used the Harris, et al. (2003) test to identify whether the existing cointegration vector is stationary or heteroscedastic. The findings of the analysis suggest that private investment can be enhanced by increasing public expenditures in infrastructure. The results of this study support the complementarity hypothesis, which states that stock of public capital crowds in private capital accumulation by increasing the return to private capital in

Macroeconomic Variables and Stock Market Performance: Testing for Dynamic Linkages with a Known Structural Break

This paper investigates the dynamic interactions between four macroeconomic variables and stock prices in Pakistan, using cointegration and Granger causality tests that are robust to structural breaks. The results strongly suggest cointegration between the stock prices and macroeconomic variables viz. consumer prices, industrial production, exchange rate and the market rate of interest. Estimates of bivariate error-correction models reveal that there is long-run bidirectional causation between the stock prices and all the said macroeconomic variables with the exception of consumer prices that only lead to stock prices. The results also provide some evidence that the stock prices Granger-caused by changes in interest rates in the short run. However, the analysis is unable to explore any short-run causation between the stock prices and the remaining three macroeconomic variables. It may therefore be stated that the association between the health of the stock market in the sense of a rising share prices and the health of the economy is only a long-run phenomenon.Stock Returns; Exchange Rates; Interest Rates; Industrial Output; Prices; Economic Activity; Structural Breaks; Additive-Outlier Model

Exchange rates or stock prices, what causes what: A firm level empirical investigation

The study employs cointegration, the standard Granger causality tests and vector error correction modeling technique to investigate the cause-effect association between exchange rates and stock prices for Pakistan. It uses weekly data for 70 individual securities and the trade-weighted exchange rate over the span from January 1, 1999 to March 31, 2004. The results of cointegration tests show that there is no co-movement between the said variables for most of the examined firms. On the issue of causation, the evidences are mixed. In some cases causation runs from stock prices to exchange rate whereas for some firms’ stock prices are affected by the changes in trade-weighted exchange rate. However, the analysis findings are generally supporting the asset market approach to exchange rate determination that reports no link between the said variables.Stock Price; Exchange Rate; Firm-Level; Cointegration

Plant material booklet 1: palms of Malaysia

This book is intended as quick reference for landscape architects, architects and urban planners in identifying palms for landscape planning and design of open spaces, recreational areas, residential landscape and street planting. It begins with descriptions of the indigenous or introduced palms found in Malaysia. It then discuss how palms can be used as spatial articulation features in shaping human spaces. The book also includes a set of table describing eight subfamilies of palms in alphabetical order. This booklet is the first in a series of plant material booklets on the utilization of plants in landscape planning and designs. Other titles in this series include, among others, Herbs and Medicinal Plants, Wayside Trees and Bamboos in Malaysia

Non-linear PPP in South Asia and China

This study tests the purchasing power parity hypothesis for four South Asian economies and China by employing a recent nonlinear test of stationarity. Besides testing the CPI based PPP, we have also used PPI based real exchange rate in the analysis. The results indicate that nonlinear tests are more successful in validating PPP

Economic Liberalization and the Causal Relations among Money, Income, and Prices: The Case of Pakistan

This study re-examines the causal relations between money and the two variables, i.e., income and prices. Using annual data from 1959/60 to 2003/04, examining the stochastic properties of the variables used in the analysis, and taking care of the shifts in the series due to the start of the economic liberalization program in the early 1990s, we investigate the causal relations between real money and real income, between nominal money and nominal income, and between nominal money and prices. The analysis indicates, in general, the long run relationship among money, income, and prices. The analysis further suggests a one way causation from income to money in the long run implying that probably real factors rather than money supply has played a major role in increasing Pakistan’s national income. The study fails to find the active role of money in changing income even after taking care of possible shifts in these variables due to the economic reforms. As Regards the causal relationship between money and prices, the analysis suggests a unidirectional causality from money to prices implying monetary expansion increases inflation in Pakistan.Money; Income; Prices; Economic Liberalization; Causal Relations; Pakistan