More than 19 million children participate in youth baseball and softball annually. Although baseball and softball are not commonly depicted as contact sports in the, according to the U.S. CPSC baseball and softball were responsible for 11.6% of all head injuries treated in emergency rooms in 2009; third most behind only cycling and football. Ball impact has been identified as the leading cause of injury in baseball and softball, with the most frequent injury resulting from a ball impacting the head. Reduced injury factor balls, infield softball masks, batter's helmets, and catcher's masks have all been integrated into baseball and softball as a means for preventing serious head injury from ball impact. The research in this thesis had four objectives: to compare the responses of the Hybrid III and NOCSAE headforms during high velocity projectile impacts, to compare head injury risk across a range of baseball stiffness designed for different age groups, to evaluate the effectiveness of infielder softball masks' ability to attenuate facial fracture risk, and to describe a novel methodology to evaluate the performance of batter's helmets and catcher's masks. Results of these research objectives determined the most suitable ATD headform to evaluate head injury risk for high velocity projectile impacts, provided a framework for determining the optimal age-specific ball stiffness and optimal infield mask design, and disseminated STAR ratings for batter's helmets and catcher's masks to the public. The research presented in this thesis can be used to further improve safety in baseball and softball. / MS / Baseball and softball are two commonly played sports, however, they combine to yield some of the highest head injury rates among sports. Safety measures like protective headgear and softer balls have been implemented into the games, but there is currently no metric for comparing different models and brands on their effectiveness at reducing head injury. The research in this thesis provides an evaluation system that compares the effectiveness of protective headgear between different models and brands and their ability to reduce head injury. This research is presented to the public as a purchasing tool and can be used to further improve the safety in baseball and softball.

Doctor of Philosophy / Department of Physics / Vinod Kumarappan / In general, molecules in the gas phase are free to rotate, and measurements made on such samples are averaged over a randomly oriented distribution of molecules. Any orientation dependent information is lost in such measurements. The goal of the work presented here is to a) mitigate or completely do away with orientational averaging, and b) make fully resolved orientation dependent measurements. In pursuance of similar goals, over the past 50 years chemists and physicists have developed techniques to align molecules, or to measure their orientation and tag other quantities of interest with the orientation. We focus on laser induced alignment of asymmetric top molecules. The first major contribution of our work is the development of an effective method to align all molecular axes under field-free conditions. The method employs a sequence of nonresonant, impulsive laser pulses with varied ellipticities. The efficacy of the method is first demonstrated by solution of the time dependent Schr\"{o}dinger equation for iodobenzene, and then experimentally implemented to three dimensionally align 3,5 difluoroiodobenzene. Measurement from molecules aligned in this manner greatly reduces orientational averaging. The technique was developed via a thorough understanding and extensive computations of the dynamics of rotationally excited asymmetric top molecules. The second, and perhaps more important, contribution of our work is the development of a new measurement technique to extract the complete orientation dependence of a variety of molecular processes initiated by ultrashort laser pulses. The technique involves pump-probe measurements of the process of interest from a rotational wavepacket generated by impulsive excitation of asymmetric top molecules. We apply it to make the first measurement of the single ionization probability of an asymmetric top molecule in a strong field as a function of all relevant alignment angles. The measurement and associated calculations help identify the orbital from which the electron is ionized. We expect that this technique will be widely applicable to ultrafast-laser driven processes in molecules and provide unique insight into molecular physics and chemistry.

In this thesis work, the results of microwave investigation and structural determination for benzonitrile and some of its fluorinated derivatives are presented. The pure rotational spectra of the studied compounds including benzonitrile, 2-fluorobenzonitrile, 3-fluorobenzonitrile, 2,3-difluorobenzonitrile, 2,4-difluorobenzonitrile and pentafluorobenzonitrile were investigated. Measuring the rotational spectra of the parent molecules and the minor 13C and 15N isotopic species allowed the derivation of the substitution and effective structures for these molecules. Using the effective and the calculated ab initio structures, the geometries of the fluorinated derivatives were compared to that of the reference compound (benzonitrile) and the effect of single, double and full fluorination on the geometry of benzonitrile was examined. The observed distortions in the BN geometry caused by single, double and full fluorination were interpreted by hybridization theory and intramolecular non-bonded interactions. / February 2015

It was once thought that molecules in the interstellar medium (ISM) would be destroyed in the harsh surroundings and conditions of space, and therefore unobservable by radio techniques. However, it is now understood that the chemistry of the ISM is vast and complex. The question still remains as to just how complex is this chemistry. Much is clearly still not understood. This dissertation presents work on the study of metal compounds and cations in the circumstellar envelopes of oxygen- and carbon-rich asymptotic giant branch (AGB) and supergiant stars. Laboratory studies were also conducted on several transition metal compounds of interstellar interest, some with high spin and orbital angular momentum states. Work has been completed to confirm the detection of the debated metal cyanide KCN in the carbon-rich AGB star IRC+10216. KCN joins the list as the fifth interstellar metal cyanide/isocyanide detected in this source. In addition, preliminary results on the search for TiO are presented towards the oxygen-rich supergiant star, VY CMa. To further understand the evolutionary processes of carbon- and oxygen-rich stars, a survey of HCO⁺ was taken towards the carbon star IRC+10216, the oxygen-rich AGBs TX Cam, IK Tau, and W Hya and the oxygen-rich supergiant NML Cyg. While HCO⁺ was detected towards all of these sources, the results vary. The outflow of NML Cyg proves to be asymmetric and further study is necessary. The emission from W Hya is significantly narrower than the other sources. The abundances of HCO⁺ in circumstellar gas increases inversely with mass-loss rate and ion-molecule chemistry appears to influence the chemistry of evolved circumstellar envelopes. To understand species in space with more confidence, a laboratory search for several 3d transition metal species of astrochemical interest was conducted in the laboratory: HZnCl (X¹∑⁺), ZnO (X¹∑⁺ and a³Πᵢ), ZnCl (X²∑⁺), TiS (X³Δᵣ) and CrS (X⁵Πᵣ). All of the molecules have been observed for the first time with high resolution gas phase rotational spectroscopy and the work on ZnO was the first gas-phase study of this molecule. Synthesis of the species required exotic production methods, including use of a DC discharge to produce all zinc species. By studying the rotational spectra, rest frequencies were determined that will be beneficial for future astronomical searches.

Condition monitoring of rotating shafts is gaining importance in industry due to the need to increase machine reliability and decrease the possible loss of production due to machine breakdown. In this work, the use of vibration signals for the detection of a crack within a shaft was investigated. The research involved the measurement of vibration signals during laboratory tests on a long rotating shaft rig. The focus of the experimental work was on the effect of cracks on the dynamics and the initiation and growth of cracks in the shaft. Measurements were taken from the shaft system both with simulated cracks (notches) cut at 45° and 90° to the shaft axis and with real propagating cracks initiated by a pre-crack cut. All defects were located at the mid- point along the shaft. The vibration responses and stresses were measured for different depths of crack. The vibration responses of the three different defects were compared using PSDs of the data to identify the change in position and magnitude of the peaks in the spectrum under each defect. Experiments to study the effect of defect depth at different shaft rotation speeds were also carried out. Finally, a shaft with a breathing crack (continuously opening and closing as the shaft rotates) was also studied experimentally, with the crack growing under normal steady state operating conditions. After completing the experiment work, the shaft was broken and the type of fracture studied. The results for both simulated and actual crack growth showed that vibration frequencies decreased as a crack progressed, indicating the possibility of using the vibration signal for crack detection. A significant relationship was found between the stage of crack growth and the vibration results. A finite element (FE) model was constructed to explore the relationship between the natural frequencies and crack depth and position along the shaft and to explain and validate the results of the experimental work. The FE model showed similar trends to the experimental results and also allowed the effect of different crack positions to be explored. The PSD data was fed into an artificial neural network after a feature extraction procedure was applied to significantly reduce the quantity of data whilst at the same time retaining the salient information. Such an approach results in a considerably reduced training time for the network due to the reduced complexity. The proposed scheme was shown to successfully identify the different defect levels. This method greatly enhances the capacity of an automated diagnostic process by linking increased capability in signal analysis to the predictive capability of the artificial neural network.

Diffusion processes play an important role in describing systems in many fields of science, as in physics, biology, finance and social science. One of the most famous examples of the diffusion process is the Brownian motion.    At mesoscopic scale, the Brownian theory describes the very irregular and animated motion of a particle suspended in a fluid. In this thesis, the dynamics and thermodynamics of diffusion processes driven out of equilibrium, at mesoscopic scale, are investigated.    For dynamics, the theory of Brownian motion for a particle which is able to rotate and translate in three dimensions is presented.  Moreover, it is presented how to treat diffusion process on n-dimensional Riemann manifolds defining the Kolmogorov forward equation on such manifold.   For thermodynamics, this thesis describes how to define thermodynamics quantities at mesoscopic scale using the tools of Brownian theory. The theory of stochastic energetics and how to compute entropy production along a trajectory are presented introducing the new field of stochastic thermodynamics. Moreover, the "anomalous entropy production" is introduced. This anomaly in the entropy production arises when diffusion processes are driven out of equilibrium by space dependent temperature field. The presence of this term expresses the fallacy of the overdamped approximation in computing thermodynamic quantities.    In the first part of the thesis the translational and rotational motion of an ellipsoidal particle in a heterogeneous thermal environment, with a space-dependent temperature field, is analyzed from the point of view of stochastic thermodynamics.    In the final part of the thesis, the motion of a Brownian rigid body three-dimensional space in a homogeneous thermal environment under the presence of an external force field is analyzed, using multiscale method and homogenization. / <p>QC 20170515</p>

Background: In ballistic sports like golf power production in rotational movement play a major role for performance. To hit the ball far, high clubhead speed is crucial in golf and rotational power (medicine ball throws) have shown to have a good correlation to clubhead speed. A lower golf handicap has also shown to correlate well with higher clubhead speed. Few sport specific power tests have been executed and training and testing sport specific are associated with high performance in a sport. Aim: The aim of this study was to examine the correlation between three parameters (power, velocity and force) measured in a golf specific rotational test and clubhead speed (CHS), ball speed (BS) and carry distance (CD) on young elite golfers. Methods: Twenty-six golfers, 16 men and 10 women, completed the study. Two tests were performed on separate occasion; one golf performance test using Trackman launch monitor and one golf specific rotational test in 1080 Quantum. CHS, BS and CD were collected in the golf performance test and max power, force and velocity in the golf specific rotational test. To study the relationship between the selected variables, spearman’s correlations coefficient (rs) was used and analyzed the total group, and in men and women separately. Results: Excellent correlation was found between max power and CHS (r=0.9, p&lt;0.00). Good correlation was found between force and CHS (r=0.8, p&lt;0.00). Moderate correlations were found between force and BS and force and CD and max power and CD (r=0.7, p&lt;0.00). Poor correlations were found between velocity and CHS, BS and CD (r=0.3, p&gt;0.50). Conclusion: This study showed that strong correlations seem to exist between power production in a golf specific rotation test and Golf performance in young elite golfers. Even force also seems to have an impact on golf performance while velocity showed little to no correlation to golf performance.

The theoretical part focuses on vestibular system - the formation and role of vestibular information in the control of bipedal locomotion, and processes issues of gait control with respect to walking speed and the use of sensory feedback. The experimental part deals with the effect of rotational stimulation of labyrinth on the ability to maintain straight walking direction with the exclusion of visual control at various speeds - slow walking, fast walking and running. Two groups were tested - younger group aged 21 - 30 years (29 people) and older group aged 41 - 55 years (15 people). The difference between deviations from a straight direction before stimulation (with the exclusion of visual control) and after stimulation appeared to be significant (p < 0.05) for slow walking, fast walking and running, but only in the younger group. In the younger group there was also a statistically significant difference between deviation for slow walking after rotational stimulation and deviations for fast walking and running after stimulation. In the older group there were statistically insignificant differences between deviations before and after stimulation and between various speeds. Younger and older group differed statistically significantly in response to rotational stimulation at slow walking. The results...

This research study is conducted on one bay-one story non-sway frames where the effects of the rotational restraint and slenderness ratio on the post-buckling strength of the axially restraint column under thermal load are studied. Geometric non-linear analysis of the structures is performed using a research program based on the beam-column theory. A total 32 models are created considering two different bottom end conditions: fixed and hinged, slenderness ratios: 50 and 125, and the beam to column length ratios: 0.5,1,1.5 and 2, to account for the variation in the rotational restraint. All models are subjected to thermal loads and numerical results are obtained to study the post-buckling behavior of the columns of the frames under thermal loads.

The objective of this study is to examine the effect of rotational restraints on thermal post-buckling response of sway columns using geometrically nonlinear analysis. The present design approach considers columns to have failed once they buckle. However, the columns under fire load are found to exhibit significant post-buckling strength which could be utilized for more economical design. The past researchers on the nonlinear thermal analysis used isolated columns with idealized support conditions which mean the columns are assumed to be free or fully restrained in the rotation, lateral and, axial directions. However, that is seldom the case in real structures and the restraint at an end of the column depends upon the members connected at that joint. The restraint provided to the column by the members connected at the joint will be in between the free case and fully restrained case. This study incorporates the variation in rotational restraint due to changes in the properties of members connected at the ends of the column. The columns are assumed to be fully restrained in the axial direction. Since the study is being carried out on sway columns, the restraint in the lateral direction is zero.