Testing the Effectiveness of Pollution Control Measures at the South Dade Landfill: The Reduction of Un-ionized Ammonia in Landfill Leachate

The purpose of this research was to evaluate the overall effectiveness of the pollution control measures in place at the South Dade Landfill, located in Miami, Florida. Pollution control measures in place at the landfill include the lining and capping of landfill cells, a landfill wetland retention basin and a groundwater remediation interceptor trench (GWRIT). This study was performed over a ten (10) month span beginning in October, 2002 and ending in July, 2003. This study dealt specifically with the effectiveness of the GWRIT and landfill wetlands in reducing the amount of un-ionized ammonia (NH3) in the landfill leachate. Through the analysis of surface water and groundwater surrounding the landfill, it was concluded that the pollution control measures reduced levels of un-ionized ammonia by 98% of the concentration of NH3 found in the landfill\u27s leachate

Enhanced Vertical Ground Heat Exchanger Model for Whole Building Energy Simulation

The U.S. Energy Information Agency estimates that buildings consume more than 40% of all energy used in the United States. This includes considering energy used for transportation and heavy industry. As a result, many people across the world have invested significant time and resources developing tools for predicting building performance so energy usage and costs can be optimized. One of these tools are whole building energy simulation (WBES) programs which model building geometry, building construction, and usage to estimate performance. WBES are used by 10's of thousands of architects, designers, and engineers throughout the world each day. Yet, despite this, WBES models for ground heat exchangers (GHE) suffer from a number of limitations. Often, these models rely on third-party tools to generate required data needed for simulation. They also are limited in the ability to model a significant number of common GHE configurations. This limits the abilities of designers to specify and accurately compare ground source heat pump systems to other common building conditioning systems.This study focuses on developing GHE models for use in WBES, which adds an important emphasis to minimize simulation time. In addition, the study seeks to eliminate the need for external tools to improve the accuracy of the simulation methods. This is done in three distinct parts.Load aggregation methods are characterized, a large parametric study is performed, and the results are summarized. The work performed makes recommendations for optimal load aggregation methods and parameters to minimize simulation time and maximize simulation accuracy.An enhanced ground heat exchanger model is developed and validated. The enhanced model allows users to simulate GHE at short and long simulation time steps. The model is validated against experimental data from a multi-flow rate thermal response test. A simplified dynamic borehole heat exchanger model is also developed and validated.A method for simulating the interference between thermally interacting GHE is developed and validated. A case study is presented demonstrating the method usage

The influence of injury history on countermovement jump performance and movement strategy in professional soccer players: implications for profiling and rehabilitation foci.

Context: Professional soccer players who have sustained a lower limb injury are up to 3x more likely to suffer a re-injury, often of increased severity. Previous injury has been shown to induce compensatory strategies during neuromuscular screening tests, which might mask deficits and lead to misinterpretation of readiness to play based on task outcome measures. Objective: To investigate the influence of previous injury in professional soccer players on countermovement jump (CMJ) performance and movement strategy. Design: Cross-sectional. Setting: Professional soccer club competing in the English Championship (tier 2). Patients (or other Participants): Outfield players with a minimum 6 years as a professional. Intervention(s): Players were categorised as previously injured (n=10) or not injured (n=10). All players completed double and single leg CMJ trials. Main Outcome Measures: CMJ performance was quantified as jump height and flight time:contraction time ratio. CMJ movement strategy was quantified as force-time history differentiating eccentric and concentric phases, and CMJ depth. Results: Double leg CMJ was not sensitive to previous injury in performance or movement strategy. In contrast, single leg CMJ performance was impaired in players with previous injury who generated significantly lower eccentric and concentric peak force and rate of force development, and a deeper countermovement. Impaired single CMJ performance was also evident in the non-affected limb of previously injured players, suggesting cross contamination. Hierarchical ordering revealed that the eccentric phase of the CMJ contributed little to performance in previously injured players. In non-injured players, eccentric rate of force development and concentric peak force were able to account for up to 89% of the variation in CMJ performance. Conclusions: Single leg CMJ is advocated for player profiling, being more sensitive to previous injury and negating the opportunity for inter-limb compensation strategies. Movement strategy deficits in previously injured players suggest rehabilitation foci specific to eccentric force development

A High-Speed Portable Ground Heat Exchanger Model for Use in Various Energy Simulation Software

A portable component model (PCM) of a ground source heat pump system was developed and used as a test case in the creating of a PCM development framework. By developing this framework, new building energy simulation models will be able to be easily integrated into existing simulation software such as EnergyPlus and the Modelica Buildings Library. Our model uses a time responsive g-function and numerical methods to simulate ground source heat pumps for single time steps as well as long time scales. We validated our model against GHESim and GLHEPro and found that our model agrees with these two standards within acceptable ranges of error. This allows for development of the PCM framework to have a functional test case for trouble shooting errors during the development process. Future work on this model to include non-uniform time steps would allow it to be used independent on other software as a standalone system

Iron fluorescence from within the innermost stable orbit of black hole accretion disks

The fluorescent iron Ka line is a powerful observational probe of the inner regions of black holes accretion disks. Previous studies have assumed that only material outside the radius of marginal stability can contribute to the observed line emission. Here, we show that fluorescence by material inside the radius of marginal stability, which is in the process of spiralling towards the event horizon, can have a observable influence on the iron line profile and equivalent width. For concreteness, we consider the case of a geometrically thin accretion disk, around a Schwarzschild black hole, in which fluorescence is excited by an X-ray source placed at some height above the disk and on the axis of the disk. Fully relativistic line profiles are presented for various source heights and efficiencies. It is found that the extra line flux generally emerges in the extreme red wing of the iron line, due to the large gravitational redshift experienced by photons from the region within the radius of marginal stability. We apply our models to the variable iron line seen in the ASCA spectrum of the Seyfert nucleus MCG-6-30-15. It is found that the change in the line profile, equivalent width, and continuum normalization, can be well explained as being due to a change in the height of the source above the disk. We discuss the implications of these results for distinguishing rapidly-rotating black holes from slowly rotating holes using iron line diagnostics.Comment: 20 pages, LaTeX. Accepted for publication in Astrophysical Journal. Figures 3 to 7 replaced with corrected versions (previous figures affected by calculational error). Some changes in the best fitting parameter

Experimental Investigations and Design Tool Development for Surface Water Heat Pump Systems

This study reports on experiments which were performed on spiral-helical surface water heat exchangers. These heat exchangers, when used as part of a geothermal heat pump system, serve as an alternative means whereby the system can reject heat to or extract heat from the environment. These systems are known as surface water heat pump systems and they serve as a less expensive, yet effective application of geothermal energy. Prior to this work, there was little information available to designers of surface water heat pump system regarding the performance of these heat exchangers. This work serves to bridge some of the remaining gaps by correlating heat exchanger performance in heat rejection and heat extraction modes of operation. From these correlations, design graphs were developed to allow designers of surface water heat pump systems to accurately size the surface water heat exchanger.Mechanical Engineerin

Event studies on the market value effects of new product introduction delays for focal companies and suppliers

New product introduction delays can be caused by various factors, including setbacks in overly ambitious technological advancements and quality issues. Sometimes organisations deliberately delay a new product introduction for strategic reasons, such as to avoid cannibalisation of existing products. Such delays can have negative consequences for profitability, market share and firm value. Extant studies find that such delays can be managed by designing for manufacture and optimising project scheduling. Despite this, new product introduction delays continue to plague organisations. This research shows that there is a negative market value effect not only for focal companies announcing a new product introduction delay but also for their suppliers. For focal companies, the roles of several key firm resources are studied. More specifically, when experiencing a new product introduction delay, the research observes that there is a more negative change in market value is experienced by more profitable firms and those with higher advertising intensity. However, operational slack positively moderates the impact of advertising intensity on market value. Furthermore, a study of the Boeing 787 Dreamliner's introduction delays shows that the negative market value effect spills over from the focal company to their suppliers, irrespective of whether or not they were directly involved with the affected product. Further insight demonstrates that the initial new product introduction delay is more negative compared to a further delay. A systematic literature review of new product introduction delays forms the foundation of the subsequent empirical research. Following this, the short-term event study method followed by cross-sectional regression analysis is used in this research to empirically investigate the role of firm resources on market value effects for S&P 500 companies experiencing a new product introduction delay from the perspective of signalling theory. To do so, a dataset is compiled using secondary data on new product introduction delays from LexisNexis News and stock market data from Wharton Research Data Services (WRDS), spanning a 20 year period from 1999 to 2018. Data on firm resources is retrieved from Compustat. Moving beyond the focal company, the short-term event study is also used to uncover the spillover effects of such delays for suppliers of a focal company. To do so, the Boeing 787 Dreamliner's introduction delays are used. This enables study of market value effects of new product introduction delays for the focal company (i.e. Boeing) and its suppliers. Further classification of suppliers gives further insight via t-tests. Secondary data is compiled from Bloomberg SPLC and Airframer to identify Boeing's and the Dreamliner's suppliers, whilst stock market data and further supplier data is retrieved from Datastream. This data focuses on the initial delay to the Dreamliner introduction in 2007 and a further delay in 2009. The findings of this research provide important contributions to research and practice. The results advance the field by improving the understanding of the market value effects of new product introduction delays for both focal companies and suppliers. The findings provide knowledge to how their firm resources may be associated with a more or less negative market value if and when they experience a new product introduction delay. It is imperative to uncover the market value effects of new product introduction delays beyond the focal company for other parties, such as suppliers, because not doing so missed a large part of understanding of what impact such delays have on various organisations. This research is intended to stimulate further research on what new product introduction delays mean for organisations in the hope of developing more effective ways of managing and potentially preventing such delays. The main limitations of this research are that the event study method assumes the efficient market hypothesis when in reality markets may not always operate perfectly efficiently. Secondly, event studies measuring market value changes can only analyse public limited companies (PLCs), meaning the impact of such delays on companies which are not listed on a stock market is uncertain

Connections Impact on Student Persistence: Impact Report Spring 2015 to Fall 2018

Connections is Utah State University\u27s (USU) first-year seminary. A primary objective of Connections is student persistence. It is designed to help students become learners. While being a learner is not synonymous with being a college student, it aligns students’ expectations with what is required to succeed in college and at USU. This impact report explores the influence of Connections participation on student persistence to the next term. Participation in Connections is associated with a 1.4% increase in persistence to the next term. The positive impact of Connections is increasing with strategic programmatic changes