Analytic Versus Non-Analytic Decision Makers and Their Effect on Win Percentage after In-season Player Acquisitions

This paper examines whether teams with winning records that employ analytic decision makers see a higher increase in win percentage after in-season player acquisitions versus teams that employ non-analytic decision makers. This was accomplished through analyzing the in-season player acquisition data from the MLB and NBA over the last four completed seasons through descriptive and inferential statistics. There was not a significant difference between the two groups in average win percentage after total acquisitions, trades, or signings. Using inferential tests we found no statistical significance between the type of decision maker, and the difference in win percentage after an acquisition

Adding some Dirt to Clean energy: Applying clay nanocomposites in solar cells

Polymer clay nanocomposite (PCN) thin films have found application across a number of applications, ranging from oxygen barriers to flame retardants, where their resistance to molecular gas diffusion has proven remarkably effective, even in films only a few hundred nanometers thick. Deposited using a layer-by-layer processing approach that takes advantage of self-assembly of the constituent components, these composite thin films comprise highly organized, alternating molecular layers of functional polymers and exfoliated clay platelets, commonly montmorillonite or vermiculite. Here, we explore the potential application and utility of PCN thin films in solar cells, where they serve as conformal, transparent barrier films with the potential to impact solar cell lifetime, reliability, and safety. Solar cell failures commonly result when environmental moisture and corrosive or reactive gases penetrate a cell’s encapsulant. Moreover, such cell degradation can manifest as a gradual decline in solar cell performance or, in the case when degradation leads to significantly damaged electrical elements, much more dramatic arc-faults that can lead to complete and dramatic module failure, even igniting module fires. Here, we describe how the unique nanostructure, materials chemistry, and gas barrier properties of PCNs offer promise toward addressing these challenges. Applying the PCN coatings to various elements of a solar cell module, we demonstrate the efficacy of PCNs as gas barriers, corrosion inhibitors, and arc-fault flammability mitigators. I will discuss here not only the results of our studies but also potential mechanisms for effective PCN function and present some apparent limitations of select approaches to PCN integration. These results reveal significant potential for PCNs to impact photovoltaic and other energy-related technologies, and our work highlights how these diverse, highly functional thin films may offer tremendous new opportunities for other next generation materials advances. Please click Additional Files below to see the full abstract

SolarPACES Task III Project: Analyze Heliostat Field

In recent years, great efforts have been made to reach a consensus on heliostat testing best practices. A specific SolarPACES task was launched to provide a Heliostat Testing Guidelines document for single heliostat evaluation with a focus on prototype validation and qualification. Such guidelines are not well-suited for heliostat evaluation in operating commercial heliostat fields. The commercial implementation of the Central Receiver technology is burdened by the lack of a demonstrated cost-effective methodology to test solar fields, particularly during the commissioning and operation phases of the plant. To address heliostat characterization challenges, the SolarPACES funded Project Analyze Heliostat Field aims to set the basis towards a SolarPACES guideline for Heliostat Field Performance testing under a common framework. This is by means of a review of the existing methodologies, R&D and industrial stakeholders information sharing and preparation of a future quantitative comparison and validation plan. As part of the development of this project, several meetings and a workshop involving the SolarPACES community was organized to share knowledge and experience in the measurement and characterization of heliostat fields using a range of technologies and procedures. Research centers and companies from 5 different and distant countries have actively participated in these meetings, sharing their experiences, needs and interests. This paper summarizes the outcome of this international collaborative effort and the prospects for future close collaborations sustained over time

Heat Pipe Performance Enhancement with Binary Mixture Fluids that Exhibit Strong Concentration Marangoni Effects

This research investigates the impact of Marangoni phenomena, with low mixture concentrations of alcohol and water, to enhance thermal transport capability of gravity-assisted heat pipes. The use of binary mixture working fluids in gravity-assisted heat pipes are shown to improve the critical heat flux (CHF) and operating performance, more so than with pure fluids. The CHF is responsible for dryout when the pumping rate of a liquid flow structure is not sufficient to provide enough fluid to the evaporator section. In the first study, heat pipe performance experiments were conducted for pure water and 2-propanol solutions with varying concentrations. Initial tests with pure water determined the optimal working fluid charge for the heat pipe; subsequent performance tests over a wide range of heat input levels were then conducted for each working fluid at this optimum value. The results indicated that some mixtures significantly enhance the heat transfer coefficient and heat flux capability of the heat pipe evaporator. For the best mixture tested, the maximum evaporator heat flux carried by the coolant without dryout was found to be 52% higher than the value for the same heat pipe using pure water as a coolant under comparable conditions. Peak evaporator heat flux values above 100 W/cm2 were achieved with some mixtures. Evaporator and condenser heat transfer coefficient data are presented and the trends are examined in the context of the expected effect of the Marangoni mechanisms on heat transfer. Analytical modeling effort was also conducted investigating the impact of Marangoni phenomena for low concentrations of 2-propanol/water and methanol/water mixtures. In real systems the addition of small levels of surface-active contaminants can affect the surface tension of the liquid-vapor interface and thermodynamic conditions in this region. Analysis was performed for three widely accepted binary mixture correlations to predict heat flux and superheat values for subatmospheric experimental data using bulk fluid and film thermodynamic properties. Due to the non-ideal nature of these alcohol/water mixtures, this study employs an average pseudo single-component (PSC) coefficient in place of an ideal heat transfer coefficient (HTC) to improve the correlation predictions. This investigation evaluates the ability for these correlations to predict strong Marangoni effects of mixtures that have large surface tension variation with concentration under subatmospheric conditions. It is not always clear that evaluation of bulk fluid properties will satisfactorily account for Marangoni effects. Analysis is also performed to assess correlation predictions for interfacial film properties rather than that of the bulk fluid. The results indicate that the use of film properties along with the PSC coefficient improves heat flux model predictions of subatmospheric experimental data by as much as 59.3% for 0.015M 2-propanol and 49.1% for 0.04M methanol/water mixtures, where strong Marangoni effects are believed to be more evident. A second experimental study was also performed of a 37° inclined, gravity-assisted, brass heat pipe with a 0.05M 2-Propanol/water binary mixture. The device design was developed from the first study by enlarging the evaporator and condenser surface areas. Strip heaters were also employed to provide larger input heat flux levels, for enhanced heat pipe performance testing. These experiments were carried out for varying liquid charge ratios between 30% and 70%, to determine an optimal value that would enhance heat transport performance by maximizing the critical heat flux (CHF) condition, while reducing the evaporator wall superheat. A 45% fill ratio was found to have the lowest overall superheat and highest thermal conductance by as much as 7.5W/K, as well as an enhanced CHF condition of 114.8W/cm2. A heat pipe analytical model, that characterizes binary mixture pool boiling is also presented, which was developed based on modeling efforts presented in studies 1 and 2. Model results with a 45% liquid charge ratio were found to provide good correspondence with the experimental data with an average rms evaporator vaporization heat flux deviation of 6.5%. The final study of this investigation assesses the cooling of single and dual-junction solar cells with the inclined, gravity-assisted, brass heat pipe, with a 0.05M 2-propanol/water mixture. Thermal behavior of this heat pipe solar collector system was investigated theoretically and semi-empirically through experimentation of varying input heat loads from attached strip-heaters to simulate waste heat production of single-junction monocrystalline silicon (Si), and tandem multijunction GaInP/GaAs solar cells. It was also found that the 45% liquid charge was capable of achieving the lowest superheat levels and highest critical heat flux (CHF) condition of 114.8 W/cm2, at a predicted solar concentration of 162 suns. Solar cell semiconductor theory was employed to evaluate the effects of increasing temperature and solar concentration on solar cell performance. Results showed that a combined PV/heat pipe system had a 1.7% higher electrical efficiency, at a concentration ratio 132 suns higher than a stand-alone PV system. The dual-junction system also exhibited enhanced performance at elevated system temperatures with a 2.1% greater electrical efficiency, at an operational concentration level of 560 suns higher than a stand-alone PV system. Waste heat recovery analysis of the silicon solar cell, revealed respective thermal and system efficiencies as high as 56.3% and 66.3% as the incident solar radiation and corresponding condenser heat removal factor increased to 82 suns

Design and Implementation of a Modular Mobile Robotic Base

Mobile robotic bases provide mobility for robotic serial manipulators and are essential for service technologies, warehouse applications, and robotics research. However, current mobile bases are expensive and require significant effort to integrate with robotic manipulators. The goal of this MQP was to design and implement a modular, programmable, and affordable mobile platform for interfacing with various manipulators. The team created a chassis and elevator system to increase mobility and introduce effortless electrical and mechanical integration with various manipulators utilizing a modular design. Furthermore, abstraction between user input and manipulator-specific hardware drivers was developed for seamless control of the base and manipulator

Design and Implementation of a Modular Mobile Robotic Base

Mobile robotic bases provide mobility for robotic serial manipulators and are essential for service technologies, warehouse applications, and robotics research. However, current mobile bases are expensive and require significant effort to integrate with robotic manipulators. The goal of this MQP was to design and implement a modular, programmable, and affordable mobile platform for interfacing with various manipulators. The team created a chassis and elevator system to increase mobility and introduce effortless electrical and mechanical integration with various manipulators utilizing a modular design. Furthermore, abstraction between user input and manipulator-specific hardware drivers was developed for seamless control of the base and manipulator

Fire Protection Water Sources for Nantucket

Fire hydrants on Nantucket Island are concentrated in the urban center, but many other areas are left unprotected, and alternative water source records are incomplete. A robust platform that incorporates all water source data could benefit the Nantucket Fire Department (NFD). This project aimed to recommend a mobile firefighting application for the NFD, locate and characterize water sources, and make recommendations to promote fire safety. We recommended a user-friendly application that was best suited for the NFD’s unique challenges. We also identified and mapped over 800 pools as potential alternative water sources and over 2,000 homes unprotected by hydrants. With this data, we recommended sprinkler regulation and water main infrastructure upgrades