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

LIQUIDITY RISK VS. UNDERINVESTMENT PROBLEM : AN EMPIRICAL STUDY OF THE TEXTILE SECTOR OF PAKISTAN

This research study tests the underinvestment hypothesis andthe liquidity risk hypothesis in the textile sector of Pakistan. A paneldata set of 105 textile companies has been employed over eight yearsextending from 2004-2011. Using 2-Stage Least Square Estimationprocedure (2SLS) and the Generalized Method of Moments (GMM),the empirical findings reveal that textile firms in Pakistan use highlevel of long term debt to shrink the liquidity risk which allows thefirms to use more debt. Moreover growing firms use less leverage thanthe non growing firms when exposed to high growth opportunities.The growth opportunities exhibited a negative relationship with debtmaturity but no significant economic relationship with leverage. Inthe textile sector of Pakistan leverage and short term debt maturitystructure tends to complement each other to hedge the firms againstthe liquidity risk

Alpha-glucosidase inhibitory and antioxidant activities of various extracts of aerial parts of Fagonia indica Burm. F.

Purpose: To investigate in vitro antioxidant and anti-diabetic potentials of Fagonia indica Burm.f. Var. indica in order to provide scientific evidence for its traditional use. Methods: Cold maceration method was employed for the preparation of extracts of aerial parts of the plant using chloroform, n-hexane, methanol and water as solvents. Total flavonoid and polyphenolic content of various extracts were determined by standard methods. The antioxidant and anti-diabetic activities of the extracts were determined using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and in vitro αglucosidase (maltase) inhibitory assays, respectively. Results: Preliminary results indicated the presence of various phytochemicals in the extracts. The chloroform extract exhibited the highest contents of total flavonoids (65.98 ± 1.63 mg QE/g) and polyphenols (26.75 ± 1.09 mg GAE/g). This extract also showed the highest free radical scavenging (64.74 ± 1.43 %) with IC50 value of 34.18 ± 5.57 µg/mL while the methanol extract exerted the highest αglucosidase (maltase) inhibitory activity (45.22 ± 0.46 %) with half-maximal concentration (IC50) of 220.4 ± 0.41 µg/mL. Conclusion: The extracts of the aerial parts of Fagonia indica possess significant anti-diabetic and antioxidant effect, thus justifying the traditional use of the plant for treatment of diabetes