On the Dynamics of a Weighted Bowling Ball

1979 ◽  
Vol 46 (4) ◽  
pp. 937-943 ◽  
Author(s):  
R. L. Huston ◽  
C. Passerello ◽  
J. M. Winget ◽  
J. Sears

An analysis of the dynamics and performance of a weighted, slipping/rolling bowling ball is presented. The analysis uses Euler parameters and angular velocity components as dependent variables. The governing equations of motion are integrated using standard digital/numerical procedures. Particular attention is given to factors affecting ball performance (“hook”) and the lane oil tracing on the ball. It is found that factors most affecting hook are the mass-center location, the lane conditions (friction), and the initial angular velocity component parallel to the lane.

1982 ◽  
Vol 104 (4) ◽  
pp. 785-791 ◽  
Author(s):  
P. E. Nikravesh ◽  
I. S. Chung

This paper presents a computer-based method for formulation and efficient solution of nonlinear, constrained differential equations of motion for spatial dynamic analysis of mechanical systems. Nonlinear holonomic constraint equations and differential equations of motion are written in terms of a maximal set of Cartesian generalized coordinates, three translational and four rotational coordinates for each rigid body in the system, where the rotational coordinates are the Euler parameters. Euler parameters, in contrast to Euler angles or any other set of three rotational generalized coordinates, have no critical singular cases. The maximal set of generalized coordinates facilitates the general formulation of constraints and forcing functions. A Gaussian elimination algorithm with full pivoting decomposes the constraint Jacobian matrix, identifies dependent variables, and constructs an influence coefficient matrix relating variations in dependent and indpendent variables. This information is employed to numerically construct a reduced system of differential equations of motion whose solution yields the total system dynamic response. A numerical integration algorithm with positive-error control, employing a predictor-corrector algorithm with variable order and step size, integrates for only the independent variables, yet effectively determines dependent variables.


2020 ◽  
Vol 99 (4) ◽  
pp. 405-411
Author(s):  
Elena Ju. Gorbatkova

Introduction. The important factors affecting health and performance of young people are the conditions of education, in particular, a comfortable microclimate in the classrooms of higher educational institutions. Materials and methods. In view of the urgency of this problem, an analysis was made of the microclimate parameters of educational organizations of different profiles (Ufa city, the Republic of Bashkortostan). 294 classrooms were studied in 22 buildings of 4 leading universities in Ufa. A total of 3,822 measurements were taken to determine the parameters of the microclimate. The analysis of ionizing radiation in the aerial environment of classrooms. There was performed determination of radon and its affiliated products content. In order to assess the conditions and lifestyle of students of 4 higher educational institutions of the city of Ufa, we conducted an anonymous survey of 1,820 students of I and IV years of education. Results. The average temperature in the classrooms of all universities studied was 23.9±0.09 C. The average relative humidity in all classrooms was 34.2 ± 0.42%. Analysis of ionizing radiation (radon and its daughter products decay) in the aerial environment of the classrooms and sports halls located in the basement determined that the average annual equivalent equilibrium volumetric activity of the radon daughter products (EROA ± Δ222Rn) ranged from 28 ± 14 to 69 ± 34.5 meter, which meets the requirements established by SanPiN. Conclusion. The hygienic assessment of the microclimate parameters of educational institutions of various profile revealed a number of deviations from the regulated norms. The results indicate the need to control the parameters of the microclimate, both from the administration of universities, and from the professors. According to the results of the study, recommendations were prepared for the management of higher educational institutions in Ufa.


2020 ◽  
pp. 097674792096686
Author(s):  
Yudhvir Singh ◽  
Ram Milan

Public sector banks have been merged by the government in the last few years. This is the rationale behind conducting this study. The purpose of this article is to determine the factors affecting the performance of public sector banks in India and the interrelationship between bank-specific determinants and performance of public sector banks. In this article, we shall analyse the financial data of all the public sector commercial banks for a period spread across 11 years (2009–2019); Capital adequacy, Assets quality, Management efficiency, Earning, and Liquidity (CAMEL) has been used as a performance determinant; system generalised method of moments (GMM) analysis has been used to find the effect of determinants on the performance measurement of public sector banks; and CCA (canonical correlation analysis) has been used to find the interrelationship between the bank-specific determinants and the performance of public sector banks. The finding has important implications in terms of performance in the banking sector. Certain limitations of this study are: It is based on secondary data. The study only covers the financial aspects and not the non-financial aspects. It is found that the asset quality is negatively related with performance of public sector banks. Liquidity and inflation are inversely related to performance of public sector banks in India. Capital adequacy is positively related with banks’ performance, but inversely related with banks’ interest margin. GDP growth has a significant positive impact on banks’ performance, but inversely related with banks’ interest income. Inflation rate is inversely related with banks’ performance. Banking sector reforms are insignificantly related with banks’ performance.


Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 48
Author(s):  
Mahmood Reza Azizi ◽  
Alireza Rastegarpanah ◽  
Rustam Stolkin

Motion control in dynamic environments is one of the most important problems in using mobile robots in collaboration with humans and other robots. In this paper, the motion control of a four-Mecanum-wheeled omnidirectional mobile robot (OMR) in dynamic environments is studied. The robot’s differential equations of motion are extracted using Kane’s method and converted to discrete state space form. A nonlinear model predictive control (NMPC) strategy is designed based on the derived mathematical model to stabilize the robot in desired positions and orientations. As a main contribution of this work, the velocity obstacles (VO) approach is reformulated to be introduced in the NMPC system to avoid the robot from collision with moving and fixed obstacles online. Considering the robot’s physical restrictions, the parameters and functions used in the designed control system and collision avoidance strategy are determined through stability and performance analysis and some criteria are established for calculating the best values of these parameters. The effectiveness of the proposed controller and collision avoidance strategy is evaluated through a series of computer simulations. The simulation results show that the proposed strategy is efficient in stabilizing the robot in the desired configuration and in avoiding collision with obstacles, even in narrow spaces and with complicated arrangements of obstacles.


2021 ◽  
Vol 22 (2) ◽  
pp. 348-363
Author(s):  
Damian Boniface Sambuo ◽  
Stephen Kirama ◽  
Kitala Malamsha

Determination of fish landing price is important, as the same contributes to the structure, conduct and performance of the fish market in Lake Victoria. Determination of relevant landing price is a gap to console between fishermen, agents (middlemen), processors and the government. The main objective of this study was therefore to examine fish price determination. Specifically, to examine the methods for fish price determination and analyse factors that affect fish landing price in Lake Victoria, a cross-sectional design was employed, and 300 respondents were randomly selected from two district councils, namely, Sengerema and Buchosa. Both qualitative and quantitative data were analysed using descriptive statistics and inferential analysis. Findings show that landing price is determined through formal negotiation with processors, consultation with other traders, informal negotiation with buyers and Beach Management Unit (BMU). The study concluded that these are the common methods used to determine landing prices. Also, distance from fishing to onshore landing centres, market information channels, age and experiences of the fishermen are the factors significantly found affecting landing price. It is recommended that the mechanism for setting up fishery price, fish market structure, fishery information and the formation of fishery regulatory body needs fishery policy and sector reforms that mark the determination of fish landing price.


2017 ◽  
Vol 21 (02) ◽  
pp. 1750011 ◽  
Author(s):  
KAI HOLZWEISSIG ◽  
JONAS RUNDQUIST

Formal new product development (NPD) processes have become an important tool in NPD management. However, our understanding of what makes formal NPD process implementation successful in terms of acceptance and performance is still limited. This paper contributes to an improved understanding of factors affecting the acceptance and use of formal NPD processes. Our results show that acceptance of formal NPD processes is determined by several factors, such as ease of use, transparency of discourse, continuous improvement, involvement of NPD actors, and the ability to bridge differences in thinking. Furthermore, that acceptance of formal NPD processes affects NPD performance positively. These results draw on data from a survey posted to employees working for nine large manufacturers of commercial vehicles worldwide. The results should encourage managers to consider and enhance the factors affecting acceptance. This could be done through using new media for publication to increase transparency and perceived ease of use of the NPD process. Further acceptance of the formal NPD process is increased if it mirrors an operative reality and if organisational structures for improvement of the process are implemented and inclusive to employees involved in NPD.


2015 ◽  
Vol 42 (12) ◽  
pp. 1071-1089
Author(s):  
Alan Chan ◽  
Bruce G. Fawcett ◽  
Shu-Kam Lee

Purpose – Church giving and attendance are two important indicators of church health and performance. In the literature, they are usually understood to be simultaneously determined. The purpose of this paper is to estimate if there a sustainable church congregation size using Wintrobe’s (1998) dictatorship model. The authors want to examine the impact of youth and adult ministry as well. Design/methodology/approach – Using the data collected from among Canadian Baptist churches in Eastern Canada, this study investigates the factors affecting the level of the two indicators by the panel-instrumental variable technique. Applying Wintrobe’s (1998) political economy model on dictatorship, the equilibrium level of worship attendance and giving is predicted. Findings – Through various simulation exercises, the actual church congregation sizes is approximately 50 percent of the predicted value, implying inefficiency and misallocation of church resources. The paper concludes with insights on effective ways church leaders can allocate scarce resources to promote growth within churches. Originality/value – The authors are the only researchers getting the permission from the Atlantic Canada Baptist Convention to use their mega data set on church giving and congregation sizes as per the authors’ knowledge. The authors are also applying a theoretical model on dictatorship to religious/not for profits organizations.


Author(s):  
A. R. Ohadi ◽  
G. Maghsoodi

In this paper, vibration behavior of engine on nonlinear hydraulic engine mount including inertia track and decoupler is studied. In this regard, after introducing the nonlinear factors of this mount (i.e. inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between rubber and hydraulic engine mounts, a 6 degree of freedom four cylinders V-shaped engine under inertia and balancing masses forces and torques is considered. By solving the time domain nonlinear equations of motion of engine on three inclined mounts, translational and rotational motions of engines body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of hydraulic one in low frequency region.


2003 ◽  
Vol 125 (1) ◽  
pp. 12-17 ◽  
Author(s):  
I. Hagiwara ◽  
D. W. Wang ◽  
Q. Z. Shi ◽  
R. S. Rao

A new analytical model is developed for the reduction of noise inside a cavity using distributed piezoelectric actuators. A modal coupling method is used to establish the governing equations of motion of the fully coupled acoustics-structure-piezoelectric patch system. Two performance functions relating “global” and “local” optimal control of sound pressure levels (SPL) respectively are applied to obtain the control laws. The discussions on associated control mechanism show that both the mechanisms of modal amplitude suppression and modal rearrangement may sometimes coexist in the implementation of optimal noise control.


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