573 research outputs found
Functions of Aggression and Peer Victimization in Elementary School Children: The Mediating Role of Social Preference
This study examined the longitudinal associations among functions of aggression, social preference, and peer victimization. Participants were 492 children (249 girls, 227 boys) in grades 2-5. Proactive and reactive aggression was assessed via a self-report measure and indices of social preference and peer victimization were assessed via a peer nomination inventory. Data was collected during the fall and spring of two academic years. Results suggest that the relation between aggression, social preference, and peer victimization varied by the function of aggression and gender. For girls, reactive aggression was a significant negative predictor of social preference. Findings also revealed social preference mediated the relation between reactive aggression and peer victimization for girls. This pathway did not hold for boys. There was some evidence that proactive aggression was negatively associated with peer victimization, but only for girls. Findings from the current study suggest social preference may be a key mechanism through which reactive aggression is associated with future victimization for girls. Boys’ aggression was not related to subsequent peer victimization. Future research and intervention efforts should consider gender differences and the function of aggression when investigating children’s peer victimization experiences
Minding the Gap in Domestic Violence Legislation: Should States Adopt Course of Conduct Laws?
In the United States, there is a gap between the way that sociologists, psychologists, legal scholars, and advocates define domestic violence and the way that criminal laws define domestic violence. Experts largely agree: domestic violence occurs when a partner exercises continuous power and control over the other. In this view, domestic violence occurs via a pattern of abusive behaviors that unfolds over time, and its manifestations include both physically-violent and emotionally-abusive behaviors. In contrast, criminal statutes throughout the United States continue to conceptualize domestic violence as single acts of physical violence or threats of physical violence. During the past several years, England and Wales, Ireland, and Scotland have passed laws that have attempted to bridge this gap in their own societies. The enactment of these laws abroad—and the fact that legislatures are considering similar laws in other jurisdictions, including the United States—provides a timely opportunity to analyze whether state legislatures should adopt similar laws here. This Comment argues that states should adopt domestic violence laws similar to the ones passed abroad. First, it explains why this gap between the criminal law and other understandings of domestic violence emerged, what it looks like in practice, and what its consequences are for victims throughout their experience with the criminal justice system. Second, it draws attention to the ways in which both the legislature and the criminal justice system are growing increasingly comfortable with defining and prosecuting crimes as courses of conduct. Based on the conduct covered and the harm addressed under these already existing laws, introducing similar laws in the domestic violence context would be a natural next step. Third, it evaluates course-of-conduct laws recently passed in Scotland, Ireland, and England and Wales that have attempted to close this gap. Finally, it recommends that states pass course-of-conduct domestic violence statutes, using Scotland’s law as a model
Institutionalizing Environmental Dispute Resolution Approaches Within Natural Resource Agencies: Lessons from the U.S. Forest Service
Also PCMA Working Paper #35.http://deepblue.lib.umich.edu/bitstream/2027.42/51251/1/485.pd
Guest Artist Recital: Lesley Manring, Soprano; July 31, 1977
Centennial East Recital HallSunday AfternoonJuly 31, 19772:00 p.m
Institutionalizing Conflict Management Alternatives
Also PCMA Working Paper #7.http://deepblue.lib.umich.edu/bitstream/2027.42/51116/1/348.pd
An affordable automotive hybrid transmission
It is estimated that there are more than 70 automobile models on the road today that use hybrid transmission technology for improving the efficiency of automobile transportation. Most of these transmissions are of the electric hybrid type and are expensive to purchase, and costly to maintain. The original purchase price for a vehicle with an electric hybrid transmission is approximately 3k every five to ten years with an associated disposal problem for the batteries themselves. This situation has resulted in hybrid vehicle technology being accessible to the few who are able to afford the vehicles and who normally consider themselves to be "energy buffs". By and large, hybrid vehicle technology has not been made accessible to the common automobile owner. This technology is aimed at developing a hybrid vehicle transmission that: 1) reduces the first time buying cost of the vehicle by thousands of dollars, and 2) eliminates the need for replacing expensive and environmentally dangerous batteries thus reducing maintenance costs. It so happens that this technology also eliminates conventional disc brakes that wear out and need replacement. Furthermore, this technology eliminates the reverse gear in the mechanical transmission path thus reducing the cost associated with designing and building this part of the mechanical transmission. This technology will rapidly expand the use of energy-efficient automotives as an affordable hybrid-transmission will be made available for every consumer. With over 60 million vehicles produced every year worldwide this idea will have a tremendous impact on worldwide energy consumption and the environment
Earth-based lunar atmosphere investigation Final report
Instrumentation and results of earth-based spectrometric identification of lunar atmospheric constituents in visible regio
Modeling and Designing a Hydrostatic Transmission With a Fixed-Displacement Motor
This study develops the dynamic equations that describe the behavior of a hydrostatic transmission utilizing a variable-displacement axial-piston pump with a fixed-displacement motor. In general, the system is noted to be a third-order system with dynamic contributions from the motor, the pressurized hose, and the pump. Using the Routh-Hurwitz criterion, the stability range of this linearized system is presented. Furthermore, a reasonable control-gain is discussed followed by comments regarding the dynamic response of the system as a whole. In particular, the varying of several parameters is shown to have distinct effects on the system rise-time, settling time, and maximum percent-overshoot
The influence of valve-pump weight ratios on the dynamic response of leaking valve-pump parallel control hydraulic systems
© 2018 by the authors. A new leaking valve-pump parallel control (LVPC) oil hydraulic system is proposed to improve the performance of dynamic response of present variable speed pump control (VSPC) system, which is an oil hydraulic control system with saving energy. In the LVPC, a control valve is operating at leaking status, together with a variable speed pump, to regulate the system flow of hydraulic oil simultaneously. Therefore, the degree of valve control and pump control can be adjusted by regulating the valve-pump weight ratio. The LVPC system design, mathematical model development, system parameter and control performance analysis are carried out systematically followed by an experimental for validation process. Results have shown that after introducing the valve control, the total leakage coefficient increases significantly over a wide range with the operating point and this further increases damping ratios and reduces the velocity stiffness. As the valve-pump weight ratio determines the flow distribution between the valve and the pump and the weight factors of the valve and/or the pump controls determines the response speed of the LVPC system, thus if the weight factors are constrained properly, the LVPC system will eventually have a large synthetic open-loop gain and it will respond faster than the VSPC system. The LVPC will enrich the control schemes of oil hydraulic system and has potential value in application requiring of fast response
Mapping the Efficiency for a Hydrostatic Transmission
Efficiency maps have long been used by engineers to understand the topographical behavior of their machinery. Most commonly, efficiency maps have been generated for internal combustion engines, where the torque-speed curve for the engine shows the wide-open-throttle line with constant efficiency lines drawn beneath this maximum operating limit. From such maps, engineers have been able to determine the most efficiency operating point for the engine, given a desired output power (torque and speed). There currently exists a great interest in using hydrostatic transmissions for improving the operating efficiency of an internal combustion engine. However, efficiency maps for hydrostatic transmissions, similar to efficiency maps for internal combustion engines, do not exist in the literature and therefore it is difficult to assess the overall efficiency gains that are achieved when using a hydrostatic transmission in these applications. This paper proposes a method for generating efficiency maps for hydrostatic transmissions, and presents a typical set of maps that may be used as a first approximation for assessing transmission efficiency. The results of this paper are nondimensional and are generalized for a transmission of any size. As shown in this research, there are regimes of transmission operation in which the efficiency is nearly independent of either the output torque, or the output speed. Furthermore, it is shown that maximum operating efficiencies typically exist at high output speeds, and mid-to-high output torques. [DOI: 10.1115/1.4032289] Introduction Background. A hydrostatic transmission is a continuously variable transmission (CVT) that facilitates power transfer without using a discrete number of gear ratios. These transmissions are frequently used to propel off-highway machinery for the construction and earth moving industry, as well as the lawn and garden industry. CVT technology has also become popular in the on-highway automotive industry as it allows the internal combustion engine of the vehicle to operate at its most efficient operating point for a given power requirement of the vehicle. Some have estimated that a CVT can improve the fuel efficiency of the internal combustion engine by as much as 60
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