Carry-over of force production symmetry in athletes of differing strength levels. J Strength Cond Res 29(11): 3188–3196, 2015—This study sought to determine the level of association between bilateral force production symmetry assessment methods (standing weight distribution [WtD], unloaded and lightly loaded jumps, and isometric strength) and to determine whether the amount of symmetry carry-over between these tasks differs for strong and weak athletes. Subjects for this study included male (n = 31) and female (n = 32) athletes from National Collegiate Athletic Association Division I sports. Athletes performed WtD, unloaded and lightly loaded (20 kg) static and countermovement jumps, and isometric midthigh pull (IMTP) assessments on 2 adjacent force plates. Ground reaction force data were used to calculate symmetry variables and performance-related variables. Using Pearson zero order correlations, evaluations of the amount of symmetry carry-over were made. Weight distribution correlated strongly with jump peak force (PF) (r = 0.628–0.664). Strong relationships were also observed between loading conditions for jump variables (r = 0.568–0.957) as were the relationships between jump types for PF, peak power, and net impulse (r = 0.506–0.834). Based on the pooled sample, there was a lack of association between IMTP and WtD for jump symmetry variables. However, when examining strong and weak groups, rate of force development showed moderate to strong symmetry carry-over in the strongest athletes (r = 0.416–0.589). Stronger athletes appear to display similar explosive strength symmetry characteristics in dynamic and isometric assessments, unlike weaker athletes. Strength seems to influence the amount of force production symmetry carry-over between bilateral assessments. There may be optimal loads and variables for symmetry assessment, but these may differ based on population characteristics.

Objectives: The purpose of this study was to identify the relationship between isometric force production symmetry and jumping performance in weighted and un-weighted static and countermovement jumps (SJ and CMJ). Design: Bivariate correlation between isometric force production symmetry and vertical jump performance variables. Methods: Collegiate athletes were evaluated for this study (n=36). Subjects performed SJ, CMJ, and isometric mid-thigh pulls (IMTP). Jumps were analyzed for jump height (JH) and peak power (PP). IMTP was analyzed for peak force (PF) for left and right sides, and values were calculated to produce a peak force symmetry index (PF-SI) score. Correlational statistics were performed examining the relationship between PF-SI and jump variables. Results: Moderate statistically significant negative correlations were observed between PF-SI and all jump variables, indicating that as asymmetry increases jump performance decreases. SJ correlations weakened in weighted conditions (JH r=-0.52 @ 0 kg/r=-0.39 @ 20 kg, PP r=-0.43 @ 0 kg/r=-0.34 @ 20 kg), but CMJ produced similar correlations for both conditions (JH r=-0.47 @ 0 kg/r=-0.49 @ 20 kg, PP r=-0.28 @ 0 kg/r=-0.34 @ 20 kg). Unlike the SJ, which only contains the propulsive or concentric portion of the jump, the CMJ also contains the eccentric portion and performance contributions of the stretch-shortening cycle (SSC). The addition of the SSC may play a role in the maintaining the magnitude of asymmetry in the CMJ weighted condition. Conclusions: The results indicate that force production asymmetry may be detrimental to bilateral vertical jumping performance. The findings should be considered for further investigation on sport-specific tasks.

The purpose of Understanding Why International Student Applicants Choose a Public Four-Year Institution was to apply a mixed-methods research approach to California State University, San Bernardino’s (CSUSB) international student population to better understand the factors associated with an international student’s decision-making processing to study abroad. Internationalization by institutions reflects the current two million international students studying around the world. In recent years internationalization has become more of an economic driving force, whereas in the past it was an opportunity for diversifying knowledge and research. Studies on push and pull factors reflect reasons why international students have decided to go abroad. Factors range from lack of access at home institutions for various programs to the desire to learn about Western culture. Seeing as the population of these studies is so diverse ethnically and culturally, it is important to be mindful of the various forms of capital students possess as an international student and the uniqueness this brings to each students experience. A questionnaire was utilized to gather quantitative data to provide descriptive statistics of the population, and interviews were conducted with participants to acquire the rich stories. The questionnaire submissions resulted in 52 returned surveys for a response rate of five percent. Six interviews were conducted, which provided a diverse group of international student representation for the analysis of the rich text allowing for a strong understanding of this specific case study. Based on the interviews conducted, responses reflected many of those that previous studies found. All but one interviewee mentioned the costs of attending as a deciding factor. Reputation of the institution and prestige of a US degree were also factors mentioned by the majority of participants. Both participants from African countries mentioned a lack of program availability as a reason to go abroad, while both Indian participants mentioned the desire to work after graduating for experience before returning home. Interestingly, most participants mentioned a connected family member to either the institution itself or the state of California as a reason for choosing CSUSB. The data that were collected for the purposes of this study did show some correlation to previous studies findings. The qualitative data proved useful in better understanding the needs of specific students, while also alluding to potential geographic considerations that need to be had when recruiting abroad and meeting the needs of international students around the world.

There has been increasing interest in the development of organic materials due to their unique structural and electronic properties. Organic compounds have the advantage of being able to be deposited from solution, leading to low-cost, high-area electronics production. Contorted polycyclic aromatic hydrocarbons have been shown to have potential for use in organic field-effect transistors (OFETs) and organic photovoltaic devices (OPVs) due to their supramolecular properties and charge carrier mobilities. Thiophene-based materials have also shown great promise in OFETs due to their high charge carrier mobilities, stability during device operation, solubility in organic solvents, and structural versatility. [n]Circulenes are a class of polycyclic aromatic compounds whose shape depends on the central n-membered ring. These range from bowl-shaped when n < 6, planar when n = 6, and saddle-shaped when n > 6. The shapes of these molecules, especially for the contorted circulenes, imparts interesting and useful properties such as a polarizable π-system and coordination to fullerenes. Using methods developed in our group, synthesis of [12]circulene derivatives was attempted. Synthetic difficulties, results, and a synthetic plan to overcome these problems are presented herein. 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) is a thiophene-based p-type semiconducting material with one of the highest reported OFET mobility to date. Alterations to BTBT have been made to improve device processing and tune the electronic structure. However, structural alterations have generally been limited to functionalization with electron-donating groups and extension of the π-system. The lack of electron deficient derivatives has prevented further tuning of the electronic structure. Additionally, installation of strongly electron-withdrawing substituents could give BTBT n-type character as seen with perylene diimides. Several synthetic strategies to develop BTBTs with electron-withdrawing groups were explored. Limitations to developing electron deficient BTBTs as well as synthesis and characterization of novel imide-functionalized derivatives are described.

The turbulent events of the world have resulted in a decline in the number of travelers since 2011. Nevertheless, approximately one billion international tourists still travel annually.Tourist activity plays an important role in the global economic activity. The purpose of this correlational study was to examine if a relationship exists between destination images, push and pull motives to travel, and tourists' satisfaction. The target population consisted of noncitizen and nonresident tourists of the British Virgin Islands (BVI) between March 2017 and April 2017. Oliver's expectancy-disconfirmation theory that the individual will act in a particular way because the expectation that a certain outcome follows the act formed the theoretical framework for this study. Data were collected through a self-developed paper survey using existing Likert-scale questions based on prior research to measure the study variables. A convenience sample of 257 noncitizen and nonresident tourists of the BVI resulted in 247 participants with useable responses. Standard multiple regression analysis determined whether there was a relationship between destination image, push and pull motives to travel, and BVI tourists' satisfaction. The results indicated the 2 predictors, destination image and push and pull motives to travel, accounted for approximately 17% of the variation in tourist satisfaction (R2= .166, F(2,244)= 24.233, p<.001). Either destination image and push and pull motives to travelor both predictors had a significant relationship with tourist satisfaction. The implications for positive social change include employment opportunities through various tourism sectors and for the future development of tourism profitability and sustainability benefiting the local community.

L’évolution des technologies silicium rend aujourd’hui possible le développement de nombreuses applications dans les domaines millimétriques tels que pour les systèmes de communication à très haut débit. Cette évolution se caractérise par une croissance des performances en fréquence des transistors disponibles dans ces technologies et nécessite la mise en place d’outils de mesure performants pour valider la modélisation et l’optimisation technologique de ces dispositifs. La caractérisation load-pull est une méthode incontournable pour modéliser le comportement en fort signal des transistors. En bande G [140-220 GHz], l’environnement de mesure classiquement disponible n’a plus les performances requises pour ce type de caractérisation compte tenu des pertes dans les accès au dispositif sous test. Ce travail de thèse a pour objectif de lever ce verrou en proposant de réaliser, en technologie BiCMOS 55 nm de STMicroelectronics, un banc load-pull entièrement intégré sur silicium afin d’être au plus près du dispositif à caractériser. Le mémoire est articulé autour de quatre chapitres. Le premier chapitre présente l’état de l’art de l’instrumentation actuellement disponible pour la caractérisation en puissance aux fréquences millimétriques et leurs limitations. Le second chapitre détaille la conception et la caractérisation des blocs constituant le banc intégré : le tuner et la source MMW de puissance. Le troisième chapitre décrit la réalisation et les performances du détecteur de puissance. Enfin, le quatrième chapitre présente le banc complet et son application à la caractérisation en bande G d’un dispositif bipolaire disponible dans la technologie BiCMOS 55 nm. / The evolution of silicon technologies now makes possible the development of many applications in the millimeter areas such as high speed communication systems. The evolution of these silicon technologies is characterized by the increase of the transistor performances with the frequency that requires the development of efficient radiofrequency measurement tools for accurate modeling of active components or the optimization of integrated circuits. In this framework, the load-pull characterization is an essential method to model the behavior of transistors in nonlinear region. In the G Band, the classical measurement environment typically available has not the required performance for this kind of characterization due to the losses in the accesses to the device under test. The aim of this thesis is to lift this lock by offering, in the STMicroelectronics BiCMOS 55 nm technology, a fully integrated load-pull characterization bench on silicon in order to be as close as possible to the device to characterize. The thesis manuscript is divided into four chapters. The first chapter presents the state of the art of the currently available instrumentation for power characterization at millimeter wave frequencies band and their limitations, which leads to the G band characterization bench specifications. The second chapter details the design and characterization of the mains blocks constituting the integrated bench: the tuner and the mmw power source. The third chapter present the design and characterization of the power detector. Finally, the fourth chapter presents the complete bench and its application with the G band load-pull characterization of a transistor bipolar device.

The Meridional Overturning Circulation (MOC) plays an important part in the Earth's climate, but the mechanisms that determine MOC response to climate change remain unclear. In particular, the relative importance of the adiabatic and diabatic dynamics in MOC is still under debate. This study aims to explore the relationship between the air-sea density flux and isopycnal MOC, and examine the possibility of diagnosing the adiabatic component of MOC from the air-sea density flux. This is done here using the concept of the "push-pull" mode, which consists of the adiabatic push into the deep ocean in the Northern Hemisphere and pull out of the deep ocean in the Southern Hemisphere. The evolutions of the isopycnal MOC and the "push-pull" mode are qualitatively similar. The maximum streamfunctions of the "push-pull" modes and isopycnal MOC both decrease by 3-5 Sv during 100 years, and their decrease is very similar to each other in the deep layers. In particular, the slope of the downward linear trend in the maximum is about -5 Sv per 100 years in both the "push-pull" modes and isopycanl MOC at the equator. The decrease in actual isopycnal MOC is faster at heavier densities than that at lighter densities. The first EOF mode of eigenvectors of the "push-pull" mode explains less percentage of variance than in the case of the isopycnal MOC at the equator. The detection of the global changes in MOC from the surface fluxes alone is feasible, if the surface fluxes are measured with sufficient accuracy.

Performance of asphalt mixtures depends on the properties of its constituent materials, mixture volumetrics, and external factors such as load and environment. An important material property that influences the performance of an asphalt mixture is the surface free energy of the asphalt binder and the aggregate. Surface free energy, which is a thermodynamic material property, is directly related to the adhesive bond energy between the asphalt binder and the aggregate as well as the cohesive bond energy of the asphalt binder. This thermodynamic material property has been successfully used to select asphalt binders and aggregates that have the necessary compatibility to form strong bonds and resist fracture. Surface free energy, being based on thermodynamics, assumes the asphalt binder is a brittle elastic material. In reality, the asphalt binder is not brittle and dissipates energy during loading and unloading. The total work of fracture is the culmination of all energy inputted into the sample to create two new surfaces of unit area and is dependent on the test geometry and testing conditions (e.g., temperature, loading rate, specimen size, etc.). The magnitude of the bond energy (either adhesive or cohesive) can be much smaller in magnitude when compared to the total work of fracture measured using mechanical tests (i.e., peel test, pull-off test, etc.). Despite the large difference in magnitude, there exists evidence in the literature supporting the use of the bond energy to characterize the resistance of composite systems to cohesive and/or adhesive failures. If the bond energy is to be recognized as a useful screening tool by the paving industry, the relationship between the bond energy and total work of fracture needs to be understood and verified. The effect of different types of modifications (addition of polymers, addition of anti-strip agents, and aging) on the surface free energy components of various asphalt binders was explored in order to understand how changes in the surface free energy components are related to the performance of the asphalt mixtures. After the asphalt binder-aggregate combination was explored, the next step was to study how the surface free energy of water was affected by contact with the asphalt binder-aggregate interface. Aggregates, which have a pH of greater than seven, will cause the pH of water that contacts them to increase. A change in the pH of the contacting water could indicate a change in its overall surface free energy, which might subsequently increase or decrease the water's moisture damage potential. With surface free energy fully explored, the total work of fracture was measured using pull-off tests for asphalt binder-aggregate combinations with known surface free energy components. In order to fully explore the relationship between bond energy and total work of fracture, temperature, loading rate, specimen geometry, and moisture content were varied in the experiments. The results of this work found that modifications made to the asphalt binder can have significant positive or negative effects on its surface free energy components and bond energy. Moreover, the results from the pull-off tests demonstrated that a relationship exists between bond energy (from surface free energy) and total work of fracture (from pull-off tests), and that surface free energy can be used to estimate the performance of asphalt binder-aggregate combinations.

In mobile communication new applications like wireless internet and mobile video have increased the demand of data-rates. Therefore, new more wideband systems are being implemented. Power amplifiers in the base-stations that simultaneously handle these wideband signals for many terminals (handhelds) need to be highly linear with a considerable band-width. In the past decade LDMOS has been the dominating technology for use in these RF-power amplifiers. In this work LDMOS transistors possible to fabricate in a normal CMOS process have been optimized and analyzed for RF-power applications. Their non-linear behavior has been explored using load-pull measurements. The mechanisms of the non-linear input capacitance have been analyzed using 2D TCAD simulations. The investigation shows that the input capacitance is a large contributor to phase distortion in the transistor. Computational load-pull TCAD methods have been developed for analysis of RF-power devices in high-efficiency operation. Methods have been developed for class-F with harmonic loading and for bias-modulation. Load-pull measurements with drain-bias modulation in a novel measurement setup have also been conducted. The investigation shows that the combination of computational load-pull of physical transistor structures and direct measurement evaluation with modified load-pull is a viable alternative for future design of RF-power devices. Simulations and measurements on the designed LDMOS shows a 10 to 15 % increase in drain efficiency in mid-power range both in simulations and measurements. The computational load-pull method has also been used to investigate the power capability of LDMOS transistors on SOI. This study indicates that either a low-resistivity or high-resistivity substrate should be used in manufacturing of RF-power LDMOS transistors on SOI to achieve optimum efficiency. Based on a proper substrate selection these devices exhibit a 10 % higher drain-efficiency mainly due to lower dissipated power in the devices.

The emergence of new communication standards has put a key challenge for semiconductor industry to develop RF devices that can handle high power and high data rates simultaneously. The RF devices play a key role in the design of power amplifiers (PAs), which is considered as a heart of base-station. From economical point of view, a single wideband RF power module is more desirable rather than multiple narrowband PAs especially for multi-band and multi-mode operation. Therefore, device modeling has now become much more crucial for such applications. In order to reduce the device design cycle time, the researchers also heavily rely on computer aided design (CAD) tools. With improvement in CAD technology the model extraction has become more accurate and device physical structure optimization can be carried out with less number of iterations. LDMOS devices have been dominating in the communication field since last decade and are still widely used for PA design and development. This thesis deals with the optimization of RFLDMOS transistor and its evaluation in different PA classes, such as linear, switching, wideband and multi-band applications. For accurate evaluation of RF-LDMOS transistor parameters, some techniques are also developed in technology CAD (TCAD) using large signal time domain computational load-pull (CLP) methods. Initially the RF-LDMOS is studied in TCAD for the improved RF performance. The physical intrinsic structure of RF-LDMOS is provided by Infenion Technologies AG. A reduced surface field (RESURF) of low-doped drain (LDD) region is considered in detail because it plays an important role in RF-LDMOS devices to obtain high breakdown voltage (BVDS). But on the other hand, it also reduces the RF performance due to high on-resistance (Ron). The excess interface state charges at the RESURF region are introduced to reduce the Ron, which not only increases the dc drain current, but also improve the RF performance in terms of power, gain and efficiency. The important achievement is the enhancement in operating frequency up to 4 GHz. In LDD region, the effect of excess interface charges at the RESURF is also compared with dual implanted-layer of p-type and n-type. The comparison revealed that the former provides 43 % reduction in Ron with BVDS of 70 V, while the later provides 26 % reduction in Ron together with BVDS of 64 - 68 V. In the second part of my research work, computational load pull (CLP) simulation technique is used in TCAD to extract the impedances of RF-LDMOS at different frequencies under large signal operation. Flexible matching is an issue in the design of broadband or multi-band PAs. Optimum impedance of RF-LDMOS is extracted at operating frequencies of 1, 2 and 2.5 GHz in class AB PA. After this, CLP simulation technique is further developed in TCAD to study the non-linear behavior of RF devices. Through modified CLP technique, non-linear effects inside the transistor structure are studied by conventional two-tone RF signals in time domain. This is helpful to detect and understand the phenomena, which can be resolved to improve the device performance. The third order inter-modulation distortion (IMD3) of RF- LDMOS was observed at different power levels. The IMD3 of −22 dBc is obtained at 1-dB compression point (P1-dB), while at 10 dB back off the value increases to −36 dBc. These results were also verified experimentally by fabricating a linear PA. Similarly, CLP technique is developed further for the analysis of RF devices in high efficiency operation by investigating the odd harmonic effects for the design of class-F PA. RF-LDMOS can provide a power added efficiency (PAE) of 81.2 % in class-F PA at 1 GHz in TCAD simulations. The results are verified by design and fabrication of class-F PA using large signal model of the similar device in ADS. In fabrication, a PAE of 76 % is achieved.