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Theoretical Estimation Of PkA'S Of Pyrimidines And Related Heterocycles, Rachael Ann Wessner

Browse all Theses and Dissertations

Pyrimidines and related heterocycles are an important class of compounds with a wide variety of applications. As a result, there is great interest in the chemical properties of these compounds, specifically their pKa's. Despite the importance of these compounds their reported pKa's are often only approximations or are completely absent from literature. Experimentally measuring pKa's can be challenging, especially if the pKa is below zero. Alternatively, pKa's can be estimated computationally using a Quantitative Structure-Activity Relationship (QSAR). However, most of the compounds included in this study exist as two or more forms that arise from tautomerism. Tautomerism complicates the estimation …

Designing Rich Information Experiences To Shape Learning Outcomes, Clarence Maybee, Christine Susan Bruce, Mandy Lupton, Kristen Rebmann

Libraries Faculty and Staff Scholarship and Research

Students in higher education typically learn to use information as part of their course of study, which is intended to support ongoing academic, personal and professional growth. Informing the development of effective information literacy education, this research uses a phenomenographic approach to investigate the experiences of a teacher and students engaged in lessons focused on exploring language and gender topics by tracing and analyzing their evolution through scholarly discourse. The findings suggest that the way learners use information influences content-focused learning outcomes, and reveal how teachers may enact lessons that enable students to learn to use information in ways that …

E-Book Reading Practices In Different Subject Areas: An Exploratory Log Analysis, Robert S. Freeman, E. Stewart Saunders

Libraries Faculty and Staff Scholarship and Research

Print books pose inherent difficulties for researchers who want to observe users’ natural in-book reading patterns. With e-books and logs of their use it is now possible to track several aspects of users’ interactions inside e-books, including the number and duration of their sessions with an e-book and the order in which pages are viewed. This chapter reports on a study of one-year of EBL user log data from Purdue University to identify different reading patterns or ways in which users navigate within different types of e-books—authored monographs vs. edited collections--and in e-books in different subject areas. The analysis of …

Get A Grip: A Graduate Student Research Information Portal, Program, And Plan. Presentation, Great Lakes Science Boot Camp., Nastasha E. Johnson, Dave Zwicky

Libraries Faculty and Staff Presentations

No abstract provided.

Effect Of Cooling Pad Installation On Indoor Airflow Distribution In A Tunnel-Ventilated Laying-Hen House, Hui Xue, Zhu Qiang, Ji-Qin Ni, Li Baoming, Shi Zhengxiang, Zhao Shumei, Wang Yu

School of Agricultural & Biological Engineering Faculty Publications

Extra cooling pads on the sidewalls are needed for larger poultry houses using tunnel ventilation system. Preliminary study showed that the airflow velocity going through different aisles varies greatly when the extra pads are installed at the end of sidewalls, making a “[”-shape air inlet. Combined with field tests, the CFD (computational fluid dynamics) technology was used to study the uniformity of airflow distribution in a tunnel-ventilated laying-hen house. The air distribution was first monitored in a layer house to find the main reason resulting in the variations of airflows in different aisles. Then CFD simulations were carried out with …

Numerical Simulation On Heat Transfer Performance Of Silicon Carbide/ Nitrate Composite For Solar Power Generation, Ruixin Zhou, Xiaole Chen, Yang Lu, Bei Guo

International Refrigeration and Air Conditioning Conference

KNO3 was used as the phase change material (PCM), but its thermal conductivity is too low to transfer heat between the PCM and conduction oil efficiently. In this thesis, on the basis of the previous studies (Yong Li, 2015), the solar power generation efficiency is enhanced with high temperature interval (280℃—400℃), and the new composite which are composed by the SiC honeycomb (SCH) frame and infiltrated KNO3 is simulated by using Fluent software. The results show that the new composite of the KNO3 +30%SCH suit for the requirement of the charging time and capacity in the design of the thermal …

Nano Roughness, Tamara J. Moore

School of Engineering Education Working Papers

No abstract provided.

Psychrometric Properties Of Humid Air From Multi-Fluid Helmholtz-Energy-Explicit Models, Ian Bell, Eric Lemmon, Allan Harvey

International Refrigeration and Air Conditioning Conference

Psychrometric properties of humid air are widely used in the analysis and modeling of thermal systems. In this work we present a method for obtaining these properties from the multi-fluid mixture formulation of the GERG mixture model. This mixture model was originally developed to model the thermodynamics of natural gas mixtures, and now has been extended to model thermodynamic properties relevant for carbon capture and storage. The primary advantage of this formulation is that the dry air composition is not fixed, and can be adjusted to suit the application, for instance in submarines, for Martian atmospheres, etc. We present an …

A Numerical And Experimental Study On Skin Condensers Applied To Household Refrigerators, Elias Gava Colombo, Rodolfo Da Silva Espíndola, Fernando Testoni Knabben, Claudio Melo

International Refrigeration and Air Conditioning Conference

The aim of this work is to numerically and experimentally investigate the performance characteristics of skin condensers applied to a specific household refrigerator model. To this end a mathematical model which takes into account both the heat transfer to the ambient and to the refrigerated compartments was developed. The model predicts the condenser performance from the internal and external air temperatures, geometry, mass flow rate, pressure and temperature at the heat exchanger inlet. Steady-state energy consumption tests – compressor running continuously with electric heaters being used to create artificial thermal load – were carried out in different operating conditions with …

Coupled Thermodynamic And Cfd Approaches Applied To A Supersonic Air Ejector, Sergio Croquer, Sébastien Poncet, Nicolas Galanis

International Refrigeration and Air Conditioning Conference

This paper presents a systematic comparison of ejector performance predictions by a thermodynamic and a CFD model for different operating conditions. The thermodynamic model developed by Galanis and Sorin (2015) assumes the primary flow is always choked, and irreversibilities due to viscous dissipation are taken into account through polytropic efficiencies. The CFD model developed by Croquer et al. (2015) using the software ANSYS Fluent v15.0 has already been validated for supersonic ejectors working with R134a. A standard high Reynolds number k- ω SST turbulence model coupled with the perfect gas law is used to model the turbulent air flows. The …

Optimization Of A Residential Air Source Heat Pump Using Heat Exchangers With Small Diameter Tubes, Mohamed Beshr, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

Heat exchangers play significant role in refrigeration and air conditioning systems. Ongoing research aims to improve, or at least maintain, the system performance while reducing the size, weight and cost of the heat exchangers. This in turn leads to lower system refrigerant charge and reduced environmental impact. Using heat exchangers with small tube diameters (less than 5 mm) instead of large tube diameters has been shown to be a promising solution to meet the aforementioned goals. However, shifting towards mall tube diameters requires in-depth analysis and optimization of several heat exchanger design parameters. This paper presents a multi-objective optimization of …

Theoretical And Experimental Analysis Of Expansion Devices For Meso-Scale Cooling Systems, João Fabio Parise De Lara, Claudio Melo, Joel Boeng

International Refrigeration and Air Conditioning Conference

Nowadays there is a growing interest for compact cooling systems, the so-called meso-refrigerating systems, and thus there is also a need for innovative components which could be applied in these systems. The expansion device of meso-refrigerating systems must be properly sized not only to improve the system performance but also to work properly under varying load conditions. The aim of this work is to study the expansion process of HFC-134a through two distinct expansion devices in order to get a better understanding of the fluid flow phenomena and to support the development of mathematical models. To this end an experimental …

Frost Growth Investigation And Temperature Glide Refrigerants In A Fin-And-Tube Heat Exchanger, Elie Keryakos, Joseph Toubassy, Denis Clodic, Georges Descombes

International Refrigeration and Air Conditioning Conference

Bio methane is produced by removing undesirable components such as water vapor, carbon dioxide and other pollutants in a biogas upgrading process. Frosting the water vapor contained in the biogas is one of the dehydration processes used in a biogas upgrading process. In order to simulate a frost layer on a cold plate, many models have been developed. These models are valid for a limited temperature range. In this study, heat and mass transfer equations were used in a numerical approach to model the frost growth and its densification on the external side of a fin-and-tube heat exchanger. The model …

Steady State Modeling Of Advanced Vapor Compression Systems, Mohamed Beshr, Vikrant Aute, Reinhard Radermacher

International Refrigeration and Air Conditioning Conference

The use of heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems is always increasing. This is because the HVACR systems are necessary for food production and ability to inhabit buildings that otherwise would be inhabitable. Thus, there is continued research focused on improving the efficiency and reducing the negative environmental impact of these systems. The basic vapor compression cycle (i.e., evaporator, condenser, expansion device and compressor), which is still the main underlying HVAC&R technology worldwide, has already reached its limits and researchers are investigating more creative and complex cycles to improve capacity and efficiency. This motivates the development of an …

Experimentally Validated Model Of Transient Heat Transfer Between A Magnetocaloric Packed Particle Bed And Stagnant Interstitial Fluid, Michael Goodman Schroeder, Ellen Brehob, Michael Benedict

International Refrigeration and Air Conditioning Conference

Typical simulations of packed bed active magnetocaloric regenerators rely on correlations of Nusselt number as a function of Reynolds number. These models are well understood for large ranges of Reynolds number, but experimental data is lacking as Reynolds number approaches zero.  Within a typical magnetocaloric refrigeration cycle a zero velocity or dwell condition is present.  When a cycle is heat transfer rate limited, heat transferred during dwell represents a significant portion of total heat transferred for a full cycle and must be accurately represented. An experiment was performed in order to validate a basic heat transfer model between …

Modelling Of An R-290/Poe Iso 22 Variable Speed Air Conditioner System Under Seer Conditions, Guilherme B. Ribeiro, Jader Riso Barbosa Jr.

International Refrigeration and Air Conditioning Conference

Air-conditioning applications using propane (R-290) have several environmental and thermodynamic advantages over more commonly used refrigerants, such as R-410A and R-22. This paper presents the development of a mathematical model for variable capacity air conditioning systems that use R-290/POE ISO 22 as refrigerant/lubricant. The thermodynamic performance of the refrigeration system is evaluated in terms of the SEER (Seasonal Energy Efficiency Ratio). The thermodynamic properties of the refrigerant/lubricant mixture were obtained from a departure-function approach using the Peng-Robinson equation of state. The effect of the oil on the condenser and evaporator heat transfer coefficients and pressure drops was also taken into …

Numerical Study On The Design Of Microchannel Evaporators For Ejector Refrigeration Cycles, Neal Lawrence, Stefan Elbel

International Refrigeration and Air Conditioning Conference

Two-phase ejectors are devices capable of improving the performance of refrigeration and air conditioning cycles by means of expansion work recovery. Ejector studies often focus on the design and performance of the two-phase ejector and the effect it can have on the performance of the ejector cycle. However, the ejector is not the only component of the system that can have a significant influence on the performance of the ejector cycle. Recent experimental work has shown that the effect of evaporator design on ejector cycle performance can be quite significant, though there is very little research available on the relation …

A Novice Method For Calibrating The Transient Model Of An Automotive Hvac System, Zhiyu Yang, Junye Shi, Jianmin Li, Jiangping Chen

International Refrigeration and Air Conditioning Conference

A novice method for calibrating the transient model of an automotive HVAC system is presented in this paper. Transient models can be of great importance in the development process of automotive HVAC control algorithms, especially model based ones, as it saves both time and effort. However, the calibration process is usually difficult and relies heavily on experience due to the complexity of the model. A set of customized measurement tools, which consists of several wireless temperature and humidity sensors and an OBD dongle, is used to capture time series data related to the HVAC system during normal driving. Parts of …

Understanding The Home Math Environment And Its Role In Predicting Parent Report Of Children's Math Skills, Sara Ann Hart, Colleen M. Ganley, David J. Purpura

Department of Human Development and Family Sciences Faculty Publications

There is a growing literature concerning the role of the home math environment in children's math development. In this study, we examined the relation between these constructs by specifically addressing three goals. The first goal was to identify the measurement structure of the home math environment through a series of confirmatory factor analyses. The second goal was to examine the role of the home math environment in predicting parent report of children's math skills. The third goal was to test a series of potential alternative explanations for the relation between the home math environment and parent report of children's skills, …

User-Centric Power Management For Mobile Operating Systems, Hui Chen

Wayne State University Dissertations

The power consumption of mobile devices must be carefully managed to provide a satisfied battery life to users. This target, however, recently has become more and more difficult to complete. We still cannot expect the battery life problem be solved economically shortly, even though researchers already addressed many aspects of this problem. Principally, that's because existing power management systems, which concentrate on controlling hardware power states, cannot effectively make these hardware components work in low-power mode. Why is this the case?

Based on our analysis of 14 users' device usage trace, we found that background applications generate too many activities …

The Relationship Between The Behaviors Of Students With An Emotional Impairment And The Beginning Of Academic Decline Or Success, Theresa Stephanie Walker

Wayne State University Dissertations

The poor academic and post-secondary outcomes for students with EI have been well documented for decades. Few studies exist, however, that explore where the breakdown in academics begins. Instead of compiling data that adds to this knowledge base, this study explored the academic status of students through multiple data sources. The goal of this was to determine at which level, early elementary, late elementary, middle school, or high school, a breakdown in academics can be detected and at which level interventions should occur. It also attempted to answer the question as to whether or not special education services, specifically a …

Electrocatalysis In Li-S Batteries, Hesham I. Al Salem

Wayne State University Dissertations

Stabilizing polysulfide-shuttle process while ensuring high sulfur loading holds the key to realize high theoretical energy density (2500 Wh/kg) of lithium-sulfur (Li-S) batteries. Though several carbon based porous materials have been used as host structures for sulfur and its intermediate polysulfides, the week adsorption of polysulfides on carbon surface and its poor reaction kinetics limits them from practical application. Here, we preset a novel ‘electcatalysis’ approach to stabilize polysulfide shuttle process and also enhance its red-ox kinetics. As a proof of concept, we have studied in-detail using conventional electrocatalyst i.e Pt/graphene composite, further the same extended to cost-effective electrocatalysts such …

Dynamic Privacy Management In Services Based Interactions, Nariman Tm Ammar

Wayne State University Dissertations

Technology advancements have enabled the distribution and sharing of users personal data over several data sources. Each data source is potentially managed by a different organization, which may expose its data as a Web service. Using such Web services, dynamic composition of atomic data items coupled with the context in which the data is accessed may breach sensitive data that may not comply with the users preference at the time of data collection. Thus, providing uniform access policies to such data can lead to privacy problems. Some fairly recent research has focused on providing solutions for dynamic privacy management. This …

Principals’ Perceptions Of Teacher-Student Interactions In Diversifying Suburban Middle Schools, Yolanda E. Bloodsaw

Wayne State University Dissertations

This qualitative study examined the kinds of troublesome teacher-student interactions that principals in a large Midwestern metro community manage. Personal interview data from nine suburban middle school principals as well as a group interview with four of the nine participants followed an interpretivist paradigm. This study found that the tense teacher-student interactions are triggered by conflicting perceptions held by students and teachers as a result of racial/cultural differences and socioeconomic status. Conflicting perceptions included stereotypes, cultural insensitivity, student motivation, student survival, loud Black kids, and tardiness. The bulk of the teacher-student interactions described by participants primarily concerned interactions between the …

Distribution-Free Trends Test To Determine The Construct Validity Of An Anti-Social Criminal Attitudes Scale, Holly Ann Child

Wayne State University Dissertations

The Sawilosky's I-Test was developed to as an alternative method to evaluate construct validity, more specifically, in regards to the Multitrait-Multimethod Matrix designed by Campbell and Fiske (1959). Typically, researchers use a method by Campbell and Fiske that involves a subjective “physical” look at the matrix to determine validity. Sawilowsky’s I-Test offers a statistical approach that incorporates the current practice but removes the subjectivity involved in this process.

There are only two existing studies that look at the I-Test, Sawilowsky in 2002 and Cuzzocrea in 2007. Both studies found that although the I-Test is not a perfect statistic, it provides …

Development Of The Acute Decompensated Heart Failure Risk Model For Emergency Room Resident Training, Zora Cvetkovski-Injic

Wayne State University Dissertations

The purpose of this study was to characterize patients hospitalized with acute decompensated heart failure with and without low systolic blood pressure using exploratory factor analysis (EFA). Direct and surrogate measurements were measured. The aim was to use EFA for data reduction to elicit a parsimonious set of factors summarizing the relationships between variables by measuring intercorrelations of the clinical variables collected as part of standard care, and abstracted from electronic medical records.

A better understanding of the characteristics and outcomes of the target group could potentially lead to individualized treatment modalities tailored to effectively and economically improve care. Patients …

Automated Negotiation Among Web Services, Khayyam Hashmi

Wayne State University Dissertations

Software as a service is well accepted software deployment and distribution model that is grown exponentially in the last few years. One of the biggest benefits of SaaS is the automated composition of these services in a composite system. It allows users to automatically find and bind these services, as to maximize the productivity of their composed systems, meeting both functional and non-functional requirements. In this paper we present a framework for modeling the dependency relationship of different Quality of Service parameters of a component service. Our proposed approach considers the different invocation patterns of component services in the system …

System Support For Energy Efficient Mobile Computing, Youhuizi Li

Wayne State University Dissertations

Mobile devices are developed rapidly and they have been an integrated part of our daily life. With the blooming of Internet of Things, mobile computing will become more and more important. However, the battery drain problem is a critical issue that hurts user experience. High performance devices require more power support, while the battery capacity only increases 5% per year on average. Researchers are working on kinds of energy saving approaches. For examples, hardware components provide different power state to save idle power; operating systems provide power management APIs to better control power dissipation. However, the system energy efficiency is …

Neural Circuitry Deficits Associated With Dysfunctional Myelin, Kathleen June Maheras

Wayne State University Dissertations

In the current study, we have generated mutant mice that lack Claudin 11 (Cldn11) tight junctions in CNS myelin sheaths. In myelin sheaths, Cldn11 forms tight junctions located along the outer and inner edges of the membrane spiral, preventing ions and small molecules from entering the intramyelinic space. The function of Cldn11 tight junctions is to improve the passive properties of the myelin membrane, by increasing membrane resistance and reducing capacitance, thereby improving the speed of saltatory conduction. In the absence of Cldn11, conduction velocity is slowed, most dramatically in small diameter myelinated fibers, somewhat analogous to reducing myelin thickness. …

Essays On Oil Price Volatility And Irreversible Investment, Daniel Joseph Pastor

Wayne State University Dissertations

In chapter 1, we provide an extensive and systematic evaluation of the relative

forecasting performance of several models for the volatility of daily spot

crude oil prices. Empirical research over the past decades has uncovered

significant gains in forecasting performance of Markov Switching GARCH

models over GARCH models for the volatility of financial assets and crude

oil futures. We find that, for spot oil price returns, non-switching models

perform better in the short run, whereas switching models tend to do better

at longer horizons.

In chapter 2, I investigate the impact of volatility on firms' irreversible investment decisions using real …