Using similitude theory and discrete element modeling to understand the effects of digging parameters on excavation performance for rubber tire loaders

The large sizes of mining equipment pose challenges for analysis using experiments or simulation. While scaled physical and simulation models can address this challenge, no previous work has explored how similitude theory and modeling can provide valid analysis of large equipment such as rubber tire loaders. The objective of this research was to apply similitude theory and discrete element modeling (DEM) to study the effect of different digging parameters on the penetration and the draft on the buckets of rubber tire loaders. The work sought to (1) test the hypothesis that the geometry of a rubber tire loader bucket and operating conditions significantly affects the resistive force (draft) and penetration; (2) test the hypothesis that different geometry orientations and operating conditions of a rubber tire loader bucket significantly affects draft and penetration; (3) apply DEM to scale models of rubber tire loader buckets to understand the effect of bucket geometry, orientations, and operating conditions on draft and penetration; and (4) evaluate the effectiveness of using discrete element models and similitude theory to predict draft and penetration. The results show that geometry, muckpile particle sizes, height above the floor, rake angle, speed, and motor power output are correlated to penetration and draft. This work has demonstrated that we can build valid DEM models for predicting at a larger scale. The chamfer angle of semi-spade bucket cutting blades significantly affects the draft on the buckets and 30° chamfer cut angle performs the best with the lowest peak resistive forces and energy consumption. The work finds that the forces observed during the rotation phase of the simulation are lower than the observed forces during penetration --Abstract, page iii

FAILURE OF INTEREST BASED MONETARY POLICY: EVIDENCES FROM SELECTED ISLAMIC AND NON- ISLAMIC COUNTRIES

Interest rate today is the most frequently used tool of monetarypolicy. Mainstream economists think that by increasing the interestrate, inflation can be reduced, and this provides the basis ofcontemporary monetary policy. However there is evidence againstthis theory. In this study, use the data of large number of Islamic andnon-Islamic countries. We apply sophisticated econometric techniquesincluding Granger Causality and VECM to explore the relationshipbetween interest rate and prices. We find that the relationship betweenthe two variables is positive but insignificant, showing the failure ofinterest rate as a monetary policy tool

Hand Hygiene Practices among Healthcare Professionals based on Theory of Planned Behaviour during Corona Pandemic in Pakistan.

Introduction: In the time of novel corona virus pandemic, the improper hygiene practices have significantly associated with high incidence rate of this dreadful disease spread. Theory of planned behavior is the best cognitive model to understand healthcare professional’s adherence toward hand hygiene practices. Objective: To evaluate the awareness, professional attitude and practices of health care professionals in relation to theory of planned behaviour during COVID-19.Methodology: We studied health care professionals visiting a health care facility. Systematic random sampling method was adapted for data collection with 384 sample size. Awareness, professional attitudes and practices were calculated and using theory of planned behavior, behavioral beliefs, normative beliefs and control beliefs were accessed. Results: In term of awareness and practices more than 70% of professionals were more prospective to follow hygiene of hands. However, using theory of planned behavior 70.1% of healthcare professionals were more into following hand hygiene practices but insisted to be more followed by their seniors and management.Conclusion: During COVID-19 pandemic, behavioral beliefs are strongly responsible to develop adherence toward hygiene, but such compliance is more motivated by peers, disease outbreak and self-efficacy rather than effect of hygiene itself. Awareness through workshops could be helpful to increase likelihood of compliance of hand washing practices. Keywords: Hand hygiene, normative beliefs, behavioral beliefs, control beliefs, COVID-19

Which Pairs of Stocks should we Trade? Selection of Pairs for Statistical Arbitrage and Pairs Trading in Karachi Stock Exchange

Pairs Trading refers to a statistical arbitrage approach devised to take advantage from short term fluctuations simultaneously depicted by two stocks from long run equilibrium position. In this study a technique has been designed for the selection of pairs for pairs trading strategy. Engle-Granger 2-step Cointegration approach has been applied for identifying the trading pairs. The data employed in this study comprised of daily stock prices of Commercial Banks and Financial Services Sector. Restricted pairs have been formed out of highly liquid log share price series of 22 Commercial Banks and 19 Financial Services companies listed on Karachi Stock Exchange. Sample time period extended from November 2, 2009 to June 28, 2013 having total 911 observations for each share prices series incorporated in the study. Out of 231 pairs of commercial banks 25 were found cointegrated whereas 40 cointegrated pairs were identified among 156 pairs formed in Financial Services Sector. Furthermore a Cointegration relationship was estimated by regressing one stock price series on another, whereas the order of regression is accessed through Granger Causality Test. The mean reverting residual of Cointegration regression is modeled through the Vector Error Correction Model in order to assess the speed of adjustment coefficient for the statistical arbitrage opportunity. The findings of the study depict that the cointegrated stocks can be combined linearly in a long/short portfolio having stationary dynamics. Although for the given strategy profitability has not been assessed in this study yet the VECM results for residual series show significant deviations around the mean which identify the statistical arbitrage opportunity and ensure profitability of the pairs trading strategy. JEL classifications: C32, C53, G17 Keywords: Pairs Trading, Statistical Arbitrage, Engle-Granger 2-step Cointegration Approach, VECM