\u3cem\u3eReddall v. Bryan\u3c/em\u3e and the Role of State Law in Federal Eminent Domain Jurisprudence

Prior to 1875, the standard federal takings procedure had been for state governments to condemn property on behalf of the federal government. As a result, the majority of interpretative work in the early history of eminent domain jurisprudence was undertaken by state courts. In 1853, the Maryland General Assembly granted the United States Government the power to condemn land in Maryland for an aqueduct across the Potomac to supply water to two District cities. In Reddall v. Bryan, the Maryland Court of Appeals upheld the aqueduct supplying the city of Washington with water as a public use. The Court reasoned that any constitutional use by the United States was a public use of every part of the United States—and therefore in each one of the states. Securing an adequate water supply for the Capital of the Government of the United States was in the public interest, particularly at a time when public records were vulnerable to the threat of fire. States continued to condemn land for federal projects, even as the joint takings scheme became complicated, and was no more convenient than a direct federal taking, as the case of Reddall v. Bryan demonstrates. The Federal government did not assert its power of eminent domain in its own name in its own courts until 1875

Exploitation of Digital Filters to Advance the Single-Phase T/4 Delay PLL System

With the development of digital signal processing technologies, control and monitoring of power electronics conversion systems have been evolving to become fully digital. As the basic element in the design and analysis phases of digital controllers or filters, a number of unit delays (z-1) have been employed, e.g., in a cascaded structure. Practically, the number of unit delays is designed as an integer, which is related to the sampling frequency as well as the ac signal fundamental frequency (e.g., 50 Hz). More common, the sampling frequency is fixed during operation for simplicity and design. Hence, any disturbance in the ac signal will violate this design rule and it can become a major challenge for digital controllers. To deal with the above issue, this paper first exploits a virtual unit delay (zv-1) to emulate the variable sampling behavior in practical digital signal processors with a fixed sampling rate. This exploitation is demonstrated on a T/4 Delay Phase Locked Loop (PLL) system for a single-phase grid-connected inverter. The T/4 Delay PLL requires to cascade 50 unit delays when implemented (for a 50-Hz system with 10 kHz sampling frequency). Furthermore, digital frequency adaptive comb filters are adopted to enhance the performance of the T/4 Delay PLL when the grid suffers from harmonics. Experimental results have confirmed the effectiveness of the digital filters for advanced control systems

Analysis and mitigation of dead time harmonics in the single-phase full-bridge PWM converters with repetitive controllers

In order to prevent the power switching devices (e.g., the Insulated-Gate-Bipolar-Transistor, IGBT) from shoot through in voltage source converters during a switching period, the dead time is added either in the hardware driver circuits of the IGBTs or implemented in software in Pulse-Width Modulation (PWM) schemes. Both solutions will contribute to a degradation of the injected current quality. As a consequence, the harmonics induced by the dead time (referred to as "dead time harmonics" hereafter) have to be compensated in order to achieve a satisfactory current quality as required by standards. In this paper, the emission mechanism of dead time harmonics in single-phase PWM inverters is thus presented considering the modulation schemes in details. More importantly, a repetitive controller has been adopted to eliminate the dead time effect in single-phase grid-connected PWM converters. The repetitive controller has been plugged into a proportional resonant-based fundamental current controller so as to mitigate the dead time harmonics and also maintain the control of the fundamental frequency grid current in terms of dynamics. Simulations and experiments are provided, which confirm that the repetitive controller can effectively compensate the dead time harmonics and other low-order distortions, and also it is a simple method without hardware modifications

Power Talk in DC Micro Grids: Constellation Design and Error Probability Performance

Power talk is a novel concept for communication among units in a Micro Grid (MG), where information is sent by using power electronics as modems and the common bus of the MG as a communication medium. The technique is implemented by modifying the droop control parameters from the primary control level. In this paper, we consider power talk in a DC MG and introduce a channel model based on Thevenin equivalent. The result is a channel whose state that can be estimated by both the transmitter and the receiver. Using this model, we present design of symbol constellations of arbitrary order and analyze the error probability performance. Finally, we also show how to design adaptive modulation in the proposed communication framework, which leads to significant performance benefits.Comment: IEEE SmartGridComm 201

Evaluation of a Concussion Management and Discharge Education Training Module for Emergency Department Nurses

Purpose: The purpose of this project was to improve the Emergency Department (ED) nurses’ knowledge on identifying patients at risk for concussions and delivering effective concussion discharge education using an educational training intervention. Methods: This project used a descriptive, non-randomized pre-post survey design. Participation involved three stages: a pre-education survey to assess baseline concussion education knowledge, an educational intervention consisting of a narrated PowerPoint presentation, and a post-education survey to evaluate knowledge on concussion discharge education. The intervention was delivered online via the UK Canvas educational platform. Results: The majority of nursing staff participants were female (97%) and had a bachelor’s degree as their highest level of education (91%). Of those participants, 23% did not have prior knowledge of concussion education, and roughly 75 % had less than 3 years of experience as a nurse. There was a statistically significant (p=0.005) improvement in participants’ knowledge of concussion discharge education from the pre-survey (M=20.1, SD= 1.6) to the post-survey (M=21.1, SD= 1.4). Conclusions: Findings indicate that the educational training intervention helped ED nurses gain knowledge on how to identify concussions and deliver concussion discharge education to patients, over 18 years of age suffering from concussions. As head traumas continue to be a leading diagnosis in ED’s and other Level-1 trauma settings, it is imperative to implement a standardized concussion discharge education training program for nurses such as the one implemented in this project to promote patient safety and wellbeing

A tale of two zoos : a study in watching people watching animals

Zoological gardens, or zoos, keep and display wild animals, mainly for the purposes of education, conservation and biological research. However, it is evident that a significant component of zoos is the vast number of people who visit them, since without the support of visitors, zoos would not be financially viable and would cease to exist. This research investigates the behaviours of these visitors and develops an understanding of their awareness relating to what they see and do while they are in the zoo, along with their motivations for visiting. The study focuses on two major metropolitan zoos in Australia: Adelaide (in South Australia) and Taronga (in Sydney, New South Wales). A brief historical account contextualises changes, raising awareness of the significance of visitors to the livelihood of zoos. More and more zoos are integrating into their management routines different programmes that relate to the care and welfare of the animals. Despite recent growth in scientific attention, which has focused on human-animal relationships, little research has been conducted relating to the human visitor in the zoo. To date, decisions made by administrators have been based upon assumptions of the visitors’ understanding of the work of zoos rather than on actual quantitative findings. This empirical research is significant in that it uses both quantitative and qualitative methods to appraise factual data and information. The data from unobtrusive tracking observations at different exhibits, combined with the results of questionnaire surveys, are used to explore and assess the perceptions of visitors. In developing a demographic profile of the people who visit zoos, this work considers the motivations and the frequency of visitors. Various factors that influence the viewing patterns of visitors are explored to assess the popularity of exhibits, and the perceptions of visitors relating to animals and enclosures are investigated, to assess the diverse levels of satisfaction. Case studies explore the perceptions and understandings of visitors towards the use of enrichment items, the use of signs and labels, and a hypothetical approach to the feeding of carnivores in zoos. The results are important in that they contribute essential knowledge that describes the perceptions of a wide range of people who visit zoos, along with their expectations, since it is crucial for these institutions to maintain their popularity with the public