bluuebunny/crossref_metadata_2025 huggingface dataset:
Architecture-aware Taylor shift by 1
Authors:   , Ruslanov Anatole D. , Johnson Jeremy Russell , Krandick Werner
Published: July 2021

We introduce register tiling for optimizing series of multiprecision additions. Our new tile method for designing an architecture-aware classical Taylor shift by 1 algorithm-a low-level operation important to the monomial bases variant of the Descartes method for polynomial real root isolation-obtains up to 7 times faster performance over standard implementations that call the efficient integer addition routines from the GNU Multiple Precision Arithmetic Library [44]. Our tile method for Taylor shift by 1 algorithm requires more word additions but it reduces the number of cycles per word addition by decreasing memory traffic and the number of carry computations. To enable standard compilers to tile the algorithm, we introduce signed digits, suspended normalization, radix reduction, and delayed carry propagation. The performance of our tile method depends on several parameters that can be modeled for and tuned to the underlying architecture. We show how such modeling can guide automatic code generation and automatic experimentation to adapt an algorithm to the underlying architecture for better ILP and pipeline utilization. We automatically generate our tile method for Taylor shift by 1 in a high-level language and tune it to four different processor architectures. The architecture-aware tile method outperforms four asymptotically fast methods up to degree 6000 on the four hardware platforms. We analyze feasibility of constructing high-performance architecture-aware fast methods. Using our register tiling technique, we automatically generate and tune de Castel-jau's algorithm, an operation with similar pattern of additions. The algorithm- "probably the most fundamental computation in the field of curve and surface design"(G. Farin [33])-is the main subalgorithm of the Bernstein bases variant of the Descartes method. We obtain similar performance gains. Applying our architecture-aware algorithms, we compare performance of several implementations of the monomial bases and Bernstein bases variants of the Descartes method on four processor architectures and for three classes of input polynomials. All variants have the same asymptotic computing time bound. The comparison shows that the best absolute computing times are obtained on an Opteron processor platform using the Bernstein-bases variant of the Descartes method with register tiling.
Unbalanced power converter modeling for AC/DC power distribution systems
Authors:   , Yang Xiaoguang , Miu Karen Nan
Published: July 2021

In power distribution systems, the installation of power electronics based equipment has grown rapidly for ac/dc system coupling, system protection, alternative energy source interface, etc. This thesis will focus on power electronic component and system modeling techniques and three-phase ac/dc power flow analysis for power distribution systems. First, mathematical models are developed for unbalanced power electronic converters, such as thyristor converters, diode rectifiers, and Pulse-Width-Modulated (PWM) converters. The modeling approach captures the imbalance of distribution systems using three, delta-connected, single-phase converters. In order to perform system analysis, these models have been incorporated into two types of ac/dc power flow solvers: (i) a three-phase backward/forward sequential solver and (ii) a threephase unified solver using the modified nodal analysis method. Both solvers have been applied to unbalanced radial and weakly meshed distribution systems. Finally, an ac/dc system hardware test bed was created to validate the mathematical models and the performance of the power flow solvers. Extensive hardware tests, time domain simulations, and steady-state analysis have been performed.
An examination of the long-run market reaction to the announcement of dividend omissions and reductions
Authors:   , Liu Yi , Szewczyk Samuel Hideyo
Published: July 2021

This study investigates the long-run stock performance following dividend omissions and reductions, and looks for answers for three questions: 1) Does the market underreact to announcement of dividend omissions and reductions? 2) if the market does, how long does it take for the market to correct this underreaction, and 3) are there any factors that influence the long-run underperformance? We document significantly negative long-run abnormal stock returns for up to five years after announcement by using either holding period matching approach or Fama-French calendar time portfolio regression. The results are robust across time periods and methodologies. However, we find the horizon of long-run post-announcement abnormal returns might be overstated in prior literature. When looking at each year individually, we find the abnormal performance is confined in the first postannouncement year. The long-run postannouncement abnormal returns beyond the first year reflect the compounding effects for buy-and-hold methodology and averaging effects for Fama-French calendar time regression. Our findings provide empirical support for the argument presented by Fama (1998) that the horizon of long-run anomaly is severely overstated. We find several factors that influence short-term market reaction to announcement of dividend omissions and reductions. However, most of these factors have no impact on the long-run abnormal stock performance. The magnitude of underreaction is not associated with percentage of dividend changes, reason for dividend changes, dividend yield or firm risk changes around announcement. Our paper also makes an important contribution in methodology: We caution future researchers of long-run abnormal stock performance to be aware of the fact that both buy-and-hold matching methodology and Fama-French calendar time portfolio regression tend to overstate the magnitude and horizon of long-run abnormal performance. This paper contributes to the on-going debates about the validity of Efficient Market Hypothesis.
Automatic derivation and implementation of fast convolution algorithms
Authors:   , Breitzman Anthony F. , Johnson Jeremy Russell
Published: July 2021

This thesis surveys algorithms for computing linear and cyclic convolution. Algorithms are presented in a uniform mathematical notation that allows automatic derivation, optimization, and implementation. Using the tensor product and Chinese Remainder Theorem (CRT), a space of algorithms is defined and the task of finding the best algorithm is turned into an optimization problem over this space of algorithms. This formulation led to the discovery of new algorithms with reduced operation count. Symbolic tools are presented for deriving and implementing algorithms, and performance analyses (using both operation count and run-time as metrics) are carried out. These analyses show the existence of a window where CRT-based algorithms outperform other methods of computing convolutions. Finally a new method that combines the Fast Fourier transform with the CRT methods is derived. This latter method is shown to be faster for some very large size convolutions than either method used alone.
Non-commutative harmonic analysis on certain semi-direct product groups
Authors:   , Aafif Amal , Boyer Robert Paul , Krandick Werner
Published: July 2021

Non-commutative harmonic analysis on locally compact groups is generally a difficult task due to the nature of the group representations. We present an integral operator approach with induced representations to compute the generalized Fourier transform of three dimensional semi-direct product groups. We begin with an overview of representation theory and harmonic analysis on locally compact abelian groups, compact groups and locally compact separable Type I groups. We describe induced representations and the corresponding character formulas. We analytically compute the Fourier transform and the inversion formula for semi-direct product groups given by linear transformations on the plane. Finally, numerical results are presented for the Euclidean motion group and the hyperbolic motion group.
Teacher and administrator perceptions of East Stroudsburg University's professional development school model
Authors:   , Thompson Jerald , Porter Abioseh Michael , Lynch William F.
Published: July 2021

Professional development schools (PDSs) were proposed as a way to apply a medical model of teaching to the training of teachers, to increase student achievement and bring about school reform. These innovative institutions create a partnership between public schools and universities, changing the way teachers are trained and resulting in school reform at all levels, from preschool to Grade 12 (P-12). PDS partnerships work toward high standards for educators, preparing teacher candidates to meet the needs of diverse student populations. By implementing a mixed-method study, the researcher explored administrator and teacher perceptions in a PDS developed by East Stroudsburg University and the Bethlehem Area School District. The study examined perceptions of teachers, the school administrator, and teacher candidates in the PDS . Using the NCATE (2004) PDS standards, the researcher sought to assess the PDS and to understand how the partnership develops. The NCATE standards are important to PDS research because they bring rigor to the PDS concept, provide evaluative feedback on the partnership for both the public schools and the universities, and address the outcomes associated with the PDS partnerships in order to delineate conditions that define other PDS settings. Perceptions of mentor teachers, the school administrator, and teacher candidates indicate that the East Stroudsburg University PDS is fulfilling its mission and meeting the goals of training teacher candidates better than traditional models. In contrast, questions concerning inquiry into teaching and learning-a cornerstone of the PDS model-had fewer positive responses than questions concerning the collaborative community. It may be surmised that teachers regularly engage in inquiry-related studies as a part of professional practice. Implications of the current study suggest that creating a PDS partnership can develop a collaborative atmosphere focused on improved student achievement, improved training for teacher candidates, and improved practice for mentor teachers. University and P-12 schools should continue to form partnerships, use the NCATE standards as a developmental tool to evaluate partnerships, and encourage PDSs to develop over time and implementation.
The impact of brief acceptance-based versus control-based interventions on distress tolerance in early lapsing nicotine dependent individuals
Authors:   , Murray Heather W. , Herbert James D.
Published: July 2021

The prevalence of nicotine dependence continues to be a major public health concern. Despite advances in treatments, many smokers continue to be dependent on nicotine, and often relapse within hours or days of cessation attempts. Preliminary investigations indicate that the level of tolerance for the distress of nicotine withdrawal is a key factor in early smoking lapse and subsequent relapse. In this pilot study, the effect of brief interventions on early lapsing nicotine dependent individuals' ability to tolerate psychological and physiological distress as imposed by laboratory challenges was examined. Participants were early lapsing nicotine dependent individuals, a population of smokers that has elevated risk of maintaining smoking habits. Participants were randomly assigned to one of three 30-minute interventions: 1) an acceptance-based brief intervention that promoted experiential acceptance, 2) a control-based brief intervention that encouraged attempts to alter or change thoughts, or 3) a health consequences comparison condition thought to increase awareness of health problems related to smoking. Participants' distress tolerance significantly increased during the psychological and physiological stressors, but distress tolerance did not differ across groups. In addition, differences between the groups in latency to smoking immediately following the termination of the stressors were not observed.
Acoustic wave induced convection and transport in gases under normal and micro-gravity conditions
Authors:   , Lin Yiqiang , Farouk Bakhtier
Published: July 2021

Acoustic wave induced convection and transport phenomena in gases by thermal and mechanical acoustic sources are numerically and experimentally studied. First, the characteristics of thermally induced acoustic waves due to rapid heating of compressible fluids are investigated. The undisturbed fluid pressure ranged from atmospheric to 8.0 MPa. The physics of the thermally induced acoustic wave and the effect of fluid properties are described and explained in detail. The flow fields generated by the thermally induced acoustic wave under microgravity and normal gravity conditions were investigated numerically. The flow field and heat transport induced by high-intensity acoustic wave fields in enclosures driven by endwall vibrations are also studied. Secondary flows (acoustic streaming) when present are found to enhance mixing and heat transfer. Secondary flow fields are also found to be significantly affected by temperature gradients in the flow field. Finally, the numerical model is applied to simulate transport in a thermoacoustic refrigerator. The temperature separation along a stack (composed of thin low-conductivity parallel plates) and the cooling effect are successfully predicted.
A three-dimensional stress MRI technique to quantify the mechanical properties of the ankle and subtalar joint
Authors:   , Ringleb Stacie Irene , Siegler Sorin
Published: July 2021

Chronic instability of the ankle and subtalar joint resulting from ligamentdamage are difficult to detect. Methods used to detect instability clinically are often unreliable and do not provide a complete picture of the joint motion. Studies were previously conducted in vitro and in vivo to improve the detection of instability and the understanding of joint motion. In vitro studies were conducted to measure the motion at the ankle and subtalar joint, however these tests cannot detect physiological conditions such as partial ligament rupture and the long-term effect of surgery. Some in vivo studies assess the motion of the hindfoot externally. These techniques are unable to detect motion at the ankle and subtalar joint and the measurements are affected by soft tissue interference. Other in vivo studies assess the internal joint motion with imaging modalities. One of these techniques uses the image processing and visualization software system 3DVIEWNIX to describe the joint motion. The 3D stress MRI (sMRI) technique was developed by combining the 3DVIWNIX software system with a MR compatible ankle-loading device to eliminate the limitations of the current in vivo methods. This method calculates morphological, architectural and kinematic properties of the joints. Data were collected from seven healthy volunteers and eight cadaver limbs. The in vitro data were obtained with the ligaments intact, after serially sectioning the anterior talofibular and the calcaneofibular ligaments and after simulated surgery. The data from the healthy volunteers were used to describe the contribution of the ankle and subtalar joint to the motion of the hindfoot and the effect of soft tissue interference on the joint motion. Significant changes were found in vitro between the condition with intact ligaments and both ligaments sectioned in the architectural and kinematic parameters at the ankle and subtalar joint. Surgical reconstruction restored these properties. 3D sMRI provides reliable measures of the morphology and architecture of the hindfoot in vivo and in vitro, describes the changes in the kinematics induced by loads in vivo and in vitro and it is capable of detecting ligament damage and the effects of surgical reconstruction in vitro.
Low temperature elastic and electronic properties of MAX phases
Authors:   , Finkel Peter , Barsoum Michel W.
Published: July 2021

The M[n+1]AX[n] phases (where M is an early transition metal, A is an A-group element and, X is C and/or N and n = 1 to 3) represent a new class of carbides and nitrides and can be best described as polycrystalline nanolaminates. They combine some of the best properties of ceramics and metals. Their physical properties (stiffness, damage and thermal shock resistance, high thermal and electrical conductivity) along with the fact they are readily machinable, make them extremely attractive in terms of the potential technological applications. Knowledge of low-temperature behavior is vital because it can provide insight into M[n+1]AX[n]-phases' physical properties. This work entails the systematic study of the elastic, electrical, galvanomagnetic and thermal properties of these materials in the 4-300 K temperature range. The elastic constants of these compounds (Ti₃SiC₂, Ti₃AlC₂ and Ti₄AlN₃) were measured over the 20-300 K temperature range. Their Young's and shear modulii determined from ultrasonic velocities were in 300-335 and 124-140 GPa range, respectively; both moduli increase slowly with decreasing temperature and reaching a maximum at temperatures below 125 K; Poisson's ratio is 0.2. The Debye temperatures, [theta][D], of these compounds calculated from the mean ultrasonic velocity are in 650-780K range which is in agreement with data obtained from low- temperature heat capacity measurements. To characterize the electronic transport properties, the resistivity, magnetoresistance, Hall effect, Seebeck coefficient and magnetic susceptibility were measured in the 4-300K range, and in magnetic fields up to 9T. All MAX-phases exhibit metal-like temperature dependence of the resistivity [rho](T). [theta][D] for most of the MAX-phases determined by fitting [rho](T) with the Bloch T5 formula were in good agreement with the values determined from elastic and calorimetric measurements. The carrier density of electrons n (or holes, p) and their mobilities were calculated utilizing a semi-classical isotropic two-band model. It was shown that most of the M[n+1]AX[n] (n=2) phases (Ti₃SiC₂, Ti₃AlC₂, Ti₃GeC₂) are nearly compensated conductors with n ~ p and total density of electrons and holes of ~1028 m³. This result also was is in agreement with conclusions based on negligible thermopower of these solids. Extensive study of electronic and galvanomagnetic properties and analysis of the results suggest M[n+1]AX[n] (n=2) phases can be characterized by relatively high charge carrier mobilities.
Brownfields revitalization projects
Authors:   , Essoka Jonathan Dumbe , Brulle Robert Joseph
Published: July 2021

The purpose of this investigation is to critically examine the relationship between urban environmental justice (EJ) communities, the benefits of brownfields revitalization and gentrification. The history of brownfields development in the United States and the cultural, technological, political, migratory and racial components shaping the creation of brownfields is reviewed. Fundamental concepts of environmental justice and gentrification with respect to their intersection and relationship to brownfields revitalization projects are discussed. The methodology is two-tiered. A pre-post statistical analysis to evaluate decadal perturbations in demographic variables within defined test areas that surround brownfields redevelopment sites is employed; the temporal range is 2000-1990. These test sites are screened for specific or selected EJ characteristics; the resulting subset is categorized into gentrification or non-gentrification models and integration measures are used to determine degrees of gentrification. Test site data is compared with control data. The second phase describes the connection between brownfields redevelopment site characteristics and the incidence of gentrification among test sites. Case studies are presented as prototypes of varied brownfields redevelopment sites and model types. These are juxtaposed with empirical results to support conclusions of the research. Implications and recommendations for further research are discussed. Results revealed that nearly 40% of the time Black racial proportions in control areas increased or remained constant while Black test site populations decreased. The analogous Latino analysis exhibited an 88% rate. Black racial displacement resulted from brownfields redevelopment projects 61% of the time; and Latino displacement, 14% of the time. By using an integration index in conjunction with statistically significant displacement data, results showed that for 14% of the EJ test sites, Blacks and Latinos experienced extreme forms of gentrification. Finally, residential segregation continues in conjunction with ethnic minority displacement from brownfields redevelopment, but the greater the level of racial segregation, the less likely brownfields redevelopment will lead to gentrification.
Factors affecting population dynamics of eastern pacific leatherback turtles (Dermochelys coriacea)
Authors:   , Tomillo Maria del Pilar Santidrián , Spotila James Robert
Published: July 2021

The leatherback turtle (Dermochelys coriacea) is critically endangered. The population of leatherbacks that nest at Parque Nacional Marino Las Baulas, in Costa Rica declined by 95% in less than 20 years. Annual mortality rate of adults was higher than expected in a natural population and mortality rates of juveniles could double those of a stable population. Conservation efforts since the Park was established in 1991 resulted in higher production of hatchlings per egg laid. However, the overall hatchling output decreased because of the decreasing number of nesting turtles. Simulations on the effect of egg poaching showed that poaching was the most important cause of population decline at Las Baulas. Heavy poaching resulted in a stepwise decline in number of nesting turtles due to consecutive reductions in each nesting stage. The nesting population declined faster and was extirpated sooner with 90% egg poaching than with 20% adult mortality. However, both protection in the ocean from fishing and on the beach are critical to the survival of the population. Behavior of hatchling leatherback turtles on the walk to the water was driven by predation risk. Hatchling leatherback turtles decreased predation risk emerging in groups and dispersing. Straightness of tracks increased during the process of departure and was lower in areas of higher exposure to light pollution. Nest success of leatherback turtles was driven by environmental variability. High temperatures in the nest reduced its success, and high rainfall and low ambient temperatures resulted in higher production of hatchlings. Predicted emergence success was related to El Niño Southern Oscillation (ENSO). Leatherback female turtles increased reproductive success over time by increasing number of eggs, number of clutches and arriving earlier in the season, when hatchling production was greater. In conclusion, the population decline at Las Baulas was mainly caused by egg poaching but is still threatened by high mortality in the ocean. Conservation efforts have been efficient at increasing hatchling production. However, the stochastic nature of nest success and consequently, recruitment rate, may increase the risk of extinction of a population already reduced from past poaching and fisheries.
Optimal matching and deterministic sampling
Authors:   , Abrahamson Jeff , Shokoufandeh Ali
Published: July 2021

Randomness is a fundamental problem in theoretical computer science. This research considers two questions concerning randomness. First, it examines some extremal point matching problems, exploring the dependence of matching weight with partition cardinality in vertex-weighted bipartite graphs. Second, it considers the problem of subset selection, providing several deterministic algorithms for point selection that are as good as or better than random subset selection according to various criteria.
A modeling approach for electric power transmission lines in the presence of non-fundamental frequencies
Authors:   , Cecchi Valentina , Miu Karen Nan
Published: July 2021

In light of the fact that modern power systems are expected to exhibit an increased level of harmonic and inter-harmonic frequency components, a modeling tool for electric power transmission lines was developed to determine the appropriate model structure under non-fundamental frequencies. The tool, designed for system studies, consists of a step-by-step procedure that determines the model segmentation and the corresponding parameter values of each segment. It is based on a user-defined level of accuracy and given frequencies of interest. In order to assess the accuracy of a line model, its performance is characterized through wave propagation, specifically voltage attenuation and phase shift, and is compared to the distributed parameter line model. The line modeling approach utilizes a state-of-the-art simulation tool to obtain the receiving-end voltage of the line models at the frequencies of interest. The softwarebased approach is validated with hardware tests performed within the Drexel University power engineering laboratories. An experimental platform, comprising an instrumentation and measurement system and power hardware, was designed and developed specifically to study waveform propagation in lumped circuit equivalents of transmission lines at non-fundamental frequencies. For demonstration purposes, the proposed modeling approach was applied to a short-length and a long-length line of given cable type. Results were then validated through hardware tests.
Favorite songs and adaptation during adolescence
Authors:   , Patterson Margret Hofmann , Schelly Hill Ellen
Published: July 2021

This study examines the role that favorite songs play in the adaptational processduring adolescence. In recent years, concern about the effects that popular music has onteenagers has been expressed by parents, religious groups, the medical community, andpolitical agencies because of the lyrical and musical content of the music (Took andWeiss, 1994). However, there is little research that demonstrates a causal relationship between popular music and destructive behavior in adolescents (Hoga and Bar-On, 1996). The purpose of this study is to examine the role that favorite songs play during adolescence, especially their use as a mechanism for reaching the developmental andpsychological milestones of the time period, such as the development of identity andautonomy from parental figures (Thompson and Larson, 1995). Through a content analysis of interviews with adolescents regarding what their favorite songs meant to them, it was found that songs do indeed function as an adaptational tool, helping adolescents to negotiate developmental milestones in the passage to adulthood. Upon initial analysis, the categories of response most often seen in interview content were favorite songs providing feelings of connectedness, understanding, and intimacy. Furtheranalysis revealed additional categories of response, including favorite songs evokingmemories and contributing to a sense of personal history, and favorite songs helping the adolescent to cope with stress. This information may prompt music therapists torecognize favorite songs as a means to gain understanding of the developmental tasks thatthe adolescent client is negotiating at a given time, and whether or not thesedevelopmental tasks are being achieved successfully (McConville, 1995).
Logic-based optimal control for shipboard power system management
Authors:   , Mensah Edoe F. , Kwatny Harry G.
Published: July 2021

The capability to dynamically reconfigure future naval integrated electric power systems is central to the Navy's vision of the future combat ship. The objective in this thesis is to design, implement and evaluate a Shipboard Power System Management system that will prevent loss of power at critical buses when damage conditions are encountered. The approach that we are proposing is based on a new paradigm for the design of optimal control systems for hybrid systems, i.e., systems composed of continuous dynamics and discrete events. Discrete events may involve external disturbances, the discrete action of protection devices or control systems. The essence of the idea is that the discrete acting subsystems are naturally associated with a set of logical conditions or logical and the continuous system dynamics are usually described by differential equations or differential-algebraic equations. We will introduce a dynamic programming method forhybrid systems that solves dynamic optimization problems involving both binary and real variables. The stability analysis of the hybrid control systems is conducted via bifurcation control analysis. The state feedback controller strategy for the mode switching of the power system is obtained through Mixed Integer Dynamic Programming. It is computed in the form of a lookup table that represents a mapping from combinations of modes, and continuous states to the required switching actions. Simulations results will be analyzed.
An approach to analyzing histology segmentations using shape distributions
Authors:   , Zhang Jasper Z. , Breen David E.
Published: July 2021

Histological images are the key ingredients in medical diagnosis and prognosis in today's medical field. They are imagery acquired by analysts from microscopy to determine the cellular structure and composition of a patient's biopsy. This thesis provides an approach to analyze the histological segmentation obtained from histological images using shape distributions and provides a computationally feasible method to predict their histological grade. This process provides a way of generating suggestions using segmented images in a way that is independent of the segmentation process. The process generates histograms for each image that describes a set of shape distributions generated from eight metrics that we have devised. The shape distributions are extracted from a learning set that the user provides. The shape distributions are then analyzed by querying a classification for each case using K-nearest-neighbor. The quality of the classifications is measured by a composite measure composed of precision and recall based on the query.
Functionalization of carbon nanotubes
Authors:   , Korneva Guzeliya , Schweitzer-Stenner Reinhard , Gogotsi Yury
Published: July 2021

Carbon nanotubes have unique properties that make them attractive for different engineering applications. However, because of their chemical inertness, carbon nanotubes have to be functionalized in order to acquire additional physico-chemical properties. Large multiwalled carbon nanotubes are different from fullerenes and singlewalled nanotubes because the stresses in their walls are almost relaxed while most chemical methods for fullerene functionalization exploit this effect of stressed bonds. The objective of this work is to develop new methods for functionalization of multiwalled carbon nanotubes. This work is dedicated to study two functionalization methods. The first deals with physico-chemical functionalization by filling the nanotube interior with colloidal suspensions. Irreversible adsorption of functional nanoparticles on the nanotube wall leads to the nanotube functionalization. The second method is purely chemical functionalization, which uses the reaction of cyclopropanation to break [pi] -bonds in the benzene rings of the nanotubes with formation of new [sigma]-bonds with deprotonated malonate. This so-called Bingel reaction has been used in fullerene chemistry and in this work was applied for the first time to functionalize multiwalled carbon nanotubes. While capillary filling of carbon nanotubes was known long ago, the research community was skeptical about possibility of engulfing nanoparticles into nanotubes by capillary forces. We developed and implemented capillary method to fill nanotubes with different nanoparticles. Using this method, magnetic carbon nanotubes were produced for the first time. Synthesized nanotubes have very high magnetic moment and allow to manipulate them by magnetic field. These magnetic nanotubes have been successfully used in fabrication of carbon nanotube-tipped pipettes for biological probes. The Bingel reaction was studied on three sets of multiwalled carbon nanotubes with diameters: 20nm, 100nm, and 300nm. To estimate the degree of Bingel functionalization, the chemical tagging of gold nanoparticles to the malonated nanotubes was used. Gold was attached using the sulfur-gold bridges formed after the reaction of transesterification of malonated tubes with 2(methylthio)ethanol. We found that the critical size for Bingel reaction to occur along the whole nanotube wall is less than 200 nm. Larger nanotubes could be also Bingel modified, but their chemical activity is mostly observed at the nanotube ends.
Sleep-disordered breathing in children and adolescents with systemic lupus erythematosus and its association with executive functioning
Authors:   , Badgley Jennifer Ayala , Chute Douglas L.
Published: July 2021

The relationship between sleep-disordered breathing and executive functioning in children and adolescents with Systemic Lupus Erythematosus (SLE) has not been wellstudied, despite literature referring to sleep problems in individuals with SLE. The goals of this study were to examine whether sleep-disordered breathing was more prevalent in children and adolescents with SLE compared to controls, whether there was an association between sleep-disordered breathing and executive functioning, and whether certain risk factors moderated or mediated this relationship. The SLE group consisted of 22 participants whose parents completed the study questionnaires (M age = 15.5, SD = 2.70, range = 9 - 18) and of which 17 completed the cognitive testing. Twenty-four controls from an attempted demographically matched population completed a subset of the questionnaires (M age = 14.2, SD = 1.96, range = 9 - 17). Parents of those with and without SLE completed the Sleep Disorders Inventory for Students (SDIS). Parents of those with SLE also completed the Behavior Rating Inventory of Executive Function (BRIEF) and Depression and Anxiety in Youth Scale (DAYS). Participants with SLE completed the Delis-Kaplan Executive Function System Trail Making and Verbal Fluency tests and the Wechsler Intelligence Scale for Children-IV/Wechsler Adult Intelligence Scale-III Digit Span test. Disease activity and disease severity variables were collected by chart review. Results from an independent samples t-test indicated that the SLE sample did not exhibit more sleep-disordered breathing symptoms than controls. For the SLE group, correlation analyses indicated that sleep-disordered breathing symptoms were positively associated with the BRIEF Global Executive Composite score. Multiple regression analyses to determine moderation and mediation in the relationship between sleepdisordered breathing and executive dysfunction were not conducted because of a small sample size. This study suggests that sleep-disordered breathing is not a major health concern for children and adolescents with SLE, but those with more symptoms of sleepdisordered breathing may exhibit more executive functioning difficulties. This study also suggests that the BRIEF, SDIS, and DAYS questionnaires may be useful screening measures for use with this population. Given several methodological limitations, findings are preliminary. Further research is needed that incorporates larger samples.
Power system security assessment through analog computation
Authors:   , St. Leger Aaron , Nwankpa Chikaodinaka Okechi Dike
Published: July 2021

This dissertation proposes a methodology for power system security assessment through analog computation. By exploiting the strengths of analog computation a more robust security assessment can be performed as compared to traditional methods. Security assessment is currently performed by power system operators utilizing digital computers and determines the power system structure, states and level of security based on telemetered data and knowledge of the system. Ideally this process would occur in real time but due to the limitations of digital computers and telemetry systems the security assessment is currently conducted at periodic intervals of ten to fifteen minutes. This process requires a tremendous amount of computation for large systems. In order to provide updated assessment at such time intervals, not even in real time, numerous assumptions and simplifications of the power system models and analyses are required to simplify and speed up the digital computations. Due to its inherent speed and computational efficiency analog computation is proving to be a viable alternative. Analog computation by definition is continuous in time and embodies an entirely different paradigm to computing as compared to discrete time methods. Security assessment for digital computers consists of topology estimations, state estimation and contingency analysis. The theory and practical approaches to these tasks through digital, discrete time, computational methods are fairly mature at this point in time but do not translate directly to analog computation. A robust analog computation engine along with corresponding computational theory is required in order to make use of analog methods for power system security assessment. This dissertation provides the relevant theory, hardware realization and application of an analog computer for power system security assessment.
Analog methods for power system analysis and load modeling
Authors:   , Deese Anthony Steven , Nwankpa Chikaodinaka Okechi Dike
Published: July 2021

This dissertation explores how and why analog computation may be utilized to study several aspects of power system load behavior. An analog computer is one which utilizes continuous electrical signals instead of discrete bits, 0's and 1's, to represent numerical values. Generally, it is utilized to solve a set of complex nonlinear differential equations: a process referred to as analog emulation. In the first chapters, this work examines how load may be represented in a modern analog computer designed to emulate the behavior of a multi-bus power system and perform fast power-flow analysis. Focus is placed on the design, testing, and fabrication of a printer circuit (PC) board for this purpose. In later chapters, it examines the effect of system size and model complexity on analog and hybrid (combination of analog and digital hardware) computation times. Focus is placed on static security analysis (SSA) as well as a method to minimize these computation times through reduced actuation and data acquisition. In the final chapters, this work examines how analog hardware may be utilized to perform measurement-based composite load modeling. Focus is placed on the theory, design, and testing of an analog circuit to estimate the parameters of an assumed load model from network observation. The accuracy of a power-flow analysis is only as accurate as the models and parameters that it utilizes. For this reason, the utilization of analog hardware to both represent load in power-flow analysis (state determination) and model load behavior (parameter estimation) are addressed in this dissertation.
Stress, coping, and psychological distress
Authors:   , Cos Travis Andrew , Nezu Christine M.
Published: July 2021

End-Stage Renal Disease (ESRD) is a disorder of kidney failure that afflicts over 300,000 individuals in the U.S., and is fatal if left untreated. The most common medical treatment for ESRD is hemodialysis (HD), where metabolic wastes are removed, via a dialysis machine, three times a week, several hours at a time. In addition to the comorbid medical problems and direct physical effects of ESRD, HD often yields a number of dialysis-specific stressors (e.g. fluid restrictions, monotonous dialysis routine, limitations on one's ability to work). Compared to the general population, individuals on HD treatment have elevated symptoms of anxiety, depression, and life dissatisfaction. Extant research has established a robust correlation between dialysis specific-stressors and psychological distress for individuals on HD. Additionally, approach-oriented coping strategies appear to moderate the relationship between dialysis-specific stressors and psychological distress. However, no known previous HD studies have explored the moderating role of social problem-solving, which conceptualizes that effectively coping with life stressors involves the use of both emotional and problem-focused coping strategies in how a person approaches a problem (problem orientation) and how they systematically attempt to address the problem situation (problem-solving style). Social problem-solving has been demonstrated to be a significant buffering agent between life stressors and psychological distress in other populations. This study examined the moderational role of social problem-solving in a diverse sample of 54 adults receiving hemodialysis. Multiple hierarchical regression analyses examined whether specific social problem-solving scales significantly moderated the relationship between dialysis-specific stressors and three types of psychological distress (e.g. depression, anxiety, and life dissatisfaction), controlling for participant demographic factors, disease severity, and negative life events. Avoidance Problem-Solving Style was a statistically-significant moderating variable between HD stressors and depressive symptoms: Negative Problem Orientation trended towards moderation for both anxiety and depressive symptoms. The findings of this study suggest further exploration into the role of social problem-solving coping, as well as the effectiveness of Problem Solving Therapy, for individuals living with hemodialysis.
The effects of multiple discounts on consumers' product judgments
Authors:   , Cai Zhen (Jane) , Suri Rajneesh
Published: July 2021

The concept of multiple discounts refers to the situation when two or more discounts are combined together resulting in a discount larger than any of the individual discounts. Despite the increasing popularity of this practice in the marketplace, past research provides little evidence about the relative effectiveness of such discounts. For instance, compared to single discounts, offers using multiple-discounts generally require more cognitive effort by consumers to process price information. This research presents a conceptualization that explains the effect of multiple discounts on consumers' evaluation of discount offers by examining the economic, informational, and affective dimensions of such discounts. A set of hypotheses were developed regarding multiple discounts' effect on consumers' perception of savings and product quality, compared to an economically equivalent single discount. Two experimental studies investigated the way that double discounts affect product evaluations. Participants who encounter price information along with discount(s) information evaluated perception of savings, product quality, monetary sacrifice, and value. The following are some major findings:1. The product's price level may motivate different evaluation processes of the double discounts. Specifically, participants seemed to rely more on the anchoring-andadjustment heuristic when the price level is high, which results in lower perceptions of savings with double discounts than with a single discount. When the price level is low, participants process the double discounts information more thoroughly and hence no difference on perceptions of savings was found between a single discount and double discounts.2. Double discounts interrupt the price-perceived quality linkage by making the price information more complex and harder to process. In contrast, a single discount still maintains a positive relationship between price and perception of product quality. Therefore, a high price point led to higher perceptions of product quality than a low price point.3. Emotional reactions partially mediated the effect of discount format on perceptions of savings, especially for hedonic products. Double discounts created lower positive emotions than a single discount, which led to lower perceptions of savings.
Synthesis of polylactide with varying molecular weight and aliphatic content
Authors:   , Singh Vishesh M. , Cairncross Richard Allan , Palmese Giuseppe R.
Published: July 2021

Polylactide (PLA) is a bio-based, biodegradable polymer which is derived from lactic acid and has numerous potential applications, some of which are limited by its moisture barrier and thermal properties. Prior studies have been inconsistent about how moisture sorption in PLA varies with crystallinity and molecular weight. This research is a systematic study of how moisture sorption in PLA depends on molecular weight and aliphatic content via end group modification. PLA with varying aliphatic content is achieved by initiating ring opening polymerization of Llactide with different long chain aliphatic alcohols. Molecular weight was controlled by varying the ratio of L-lactide monomer to alcohol (C16 Palmityl, C10 Decyl, C4 Butyl) initiator and triethylaluminum was used as a catalyst for precise control over molecular weight. PLA with different molecular weights and with varying end groups were synthesized and characterized by GPC, DSC, and NMR. Moisture sorption in PLA was measured with a quartz crystal microbalance (QCM). QCM experiments revealedthat both molecular weight and aliphatic content contribute to sorption properties of PLA.
Chemically modified carbon nanostructures for electrospun thin film polymer-nanocomposites
Authors:   , Behler Kristopher , Gogotsi Yury
Published: July 2021

Various nano-structured carbon materials, most notably carbon nanotubes (CNTs) and nanodiamonds (NDs), are used in preparing polymer-nanocomposites. Surfacemodified NDs, multi-walled (MWCNT), double-walled (DWCNT) and triple-walled (TWCNT) have been incorporated into polymer matrix systems. Treatments include vacuum annealing, thermal oxidation in air and acid treatments (nitric and sulfuric acids for the CNTs and hydrochloric acid for NDs). Acid treatments have led to carboxylic group formation on the surface of CNTs and NDs, promoting improved dispersion. As-received, thermal and acid treated MWCNTs have been incorporated into polyvinylidene fluoride and polyamide-11 and -12 electrospun nanofibers with little improvements in the electrical conductivity. To improve the electrical properties of CNTpolyamide composites, negatively charged CNTs were self-assembled on the nanofiber's surface. At a 2 wt% loading, the electrical resistance of the nanofibers decreased two orders of magnitude (to 154 k[omega]/sq) by increasing the number of MWCNT self-assembly depositions and then another three orders of magnitude by using DWCNTs (700 [omega]/sq). Further heat treatments were used to fuse (110°C) and completely remove the nanofibers (450°C) to produce ~150 nm coatings with improved transparency, ~96% transmission, in the visible spectrum. HCl-purified NDs have also been successfully incorporated in polyamide 11 and polyacrylonitrile nanofibers leading to improvements in the mechanical properties of thefibers. Extremely high loadings of up to 90 wt% ND in the polymer have also been achieved. The Young's modulus of the ND-polyamide-11 composites increased by afactor of four, the hardness doubled and the scratch resistance was improved such that a load three times larger than used on the pure polymer was required to generate a scratch of the identical depth in the composite material. The ND-polymer films have shown about a 50% decrease in transmission in the UV-range, making these thin filmsapplicable in UV protection. Multi-layered structures were produced by using alternating thin films of NDpolymer and CNT-polymer nanofibers. These multi-layers have shown electrical resistances on par with the single-layered films as well as the same improvement in hardness, Young's modulus and scratch resistance making them attractable for multifunctionalcomposites.