Beam Misalignments and Fluid Velocities in Laser-Induced Thermal Acoustics

Beam misalignments and bulk fluid velocities can influence the time history and intensity of laser-induced thermal acoustics (LITA) signals. A closed-form analytic expression for LITA signals incorporating these effects is derived, allowing the magnitude of beam misalignment and velocity to be inferred from the signal shape. It is demonstrated how instantaneous, nonintrusive, and remote measurement of sound speed and velocity (Mach number) can be inferred simultaneously from homodyne-detected LITA signals. The effects of different forms of beam misalignment are explored experimentally and compared with theory, with good agreement, allowing the amount of misalignment to be measured from the LITA signal. This capability could be used to correct experimental misalignments and account for the effects of misalignment in other LITA measurements. It is shown that small beam misalignments have no influence on the accuracy or repeatability of sound speed measurements with LITA

Medical Humanities Education at Six Texas Medical Schools

Medical humanities has existed since the 1960s, and research shows that it can improve important physician facets such as empathy, well-being, and understanding of the human condition. However, because of the challenging nature of evaluating the impact of medical humanities implementation in medical education, no single best practice for its incorporation can be identified. Medical humanities programs and curricula vary from each other wildly, and in Texas, a state with 14 medical schools, it is especially challenging for students, educators, and administrators to get a sense of what opportunities exist across the state. In this thesis, I review the existing literature regarding medical humanities education at large and interview key experts from six prominent Texas medical schools. In doing so, I explore medical humanities, its value to medical education and practice, its common programs and curricular structures, and its particular implementations within select Texas medical schools. I bring all of this information into one central location that is easy to access and navigate. This is valuable to undergraduate students navigating medical school admissions, medical students seeking opportunities at their own schools, educators seeking collaboration with other institutions or models to implement at their own, administrators curious about the inclusion of medical humanities in an already packed curriculum, and several others. I also draw attention to trends in medical humanities education in Texas medical schools and subsequently make suggestions regarding how Texas medical schools could improve upon the current state of their medical humanities education in the future. One such suggestion involves the inclusion of programs and curricula from each of an integrated-longitudinal approach, an elective-based approach, and a scholarly concentration approach.Plan II Honors Progra

Governmental venture capital – A social capital and principal-agent related examination for Belgium, The Netherlands, Luxembourg, Austria and Germany

The underlying research study was concerned with public venture capital which is grounded in the assumption of market failure and financing gaps (Güllmann 2000; Brettel 2005) and associated with the risk of crowding-out (Colombo et al. 2016). In order to expand the research perspective and to shed new light on the public investors, this project was concerned with their strategy, with their social networks, their syndication rationales, their monitoring and mentoring in turnaround situations and their exit routes between 2015 and 2017. 67 governmental investors in Belgium, The Netherlands, Luxembourg, Austria and Germany were invited to participate in a fully structured survey. In addition, secondary data sources were examined regarding the developments of the venture capital markets, of the crowdfunding markets and of the business angels\u27 investments in the underlying countries between the phase of the financial crisis and the recent COVID-19 pandemic. The data was analysed by means of descriptive statistics and the survey results were finally validated by an additional validation study. The results, inter alia, showed that the public investors maintained comprehensive networks with different types of network partners and that social capital (Burt 1993; Lin 1999) played an important role for their business and not the provision of financings alone. Nevertheless, the results also showed that the network size did not matter for exit success on a statistically significant level and that the recent developments on the macro level called the public involvement in question

Women Striving for Leadership: The Role of Follower Perceptions and Organisational Structure

Scholars have contributed much to identifying general factors that may hinder women from assuming leadership at the workplace, such as sex differences in attitudes and behaviours, a lack of masculine characteristics, or gender stereotypes that characterise women as high on communal traits (i.e., warm, sensitive), but low on agentic traits (i.e., competitive, dominant). Nevertheless, we know little about the micro (verbal behaviour during meetings) and macro (organisational structure) factors that impact whether women emerge as leaders. Therefore, across four chapters, the present dissertation looks at the behavioural (micro) processes underlying a lower leader emergence and endorsement of women (Chapters 2 and 3), and organisational structure (macro) that impacts the intention of women to apply to leadership roles (Chapters 4 and 5)

Accuracy and uncertainty of single-shot, nonresonant laser-induced thermal acoustics

We study the accuracy and uncertainty of single-shot nonresonant laser-induced thermal acoustics measurements of the speed of sound and the thermal diffusivity in unseeded atmospheric air from electrostrictive gratings as a function of the laser power settings. For low pump energies, the measured speed of sound is too low, which is due to the influence of noise on the numerical data analysis scheme. For pump energies comparable to and higher than the breakdown energy of the gas, the measured speed of sound is too high. This is an effect of leaving the acoustic limit, and instead creating finite-amplitude density perturbations. The measured thermal diffusivity is too large for high noise levels but it decreases below the predicted value for high pump energies. The pump energy where the error is minimal coincides for the speed of sound and for the thermal diffusivity measurements. The errors at this minimum are 0.03% and 1%, respectively. The uncertainties for the speed of sound and the thermal diffusivity decrease monotonically with signal intensity to 0.25% and 5%, respectively

Composition, Structure And Development Of The Crystalline Cone Of The Superposition Compound Eye

The crystalline cone of beetles and moths is a transparent, solid structure consisting of a small number of concentrated, hydrophobic proteins. Among these polypeptides is a 67kD protein family which are found in the cones of all 9 species examined. In addition, beetle lenses contain a 125kD polypeptide that is immunologically related to a moth 100kD lens polypeptide. The high molecular weight polypeptides may also be related to the 67kD family because (i) antibodies raised against the beetle 67kD polypeptide cross-react with the moth 67kD and 100kD polypeptides, and with the beetle 125kD polypeptide, (ii) enzyme digests of 67kD and 100kD moth polypeptides yield a number of products of identical mass, and (iii) the purified 67 and 100kD polypeptides dissociate into subunits of similar molecular weight.;The profiles of crystalline cone proteins in lepidopterans and beetles may result from the cone being formed differently. In Calpodes, the proteins are synthesized and deposited in a coordinate manner in the pupa; the cone is nearly complete at adult emergence. In Onitis, the proteins are synthesized and deposited in a temporal manner; the cone is only 70% complete at adult emergence. In both species, the crystalline cone grows by deposition of granules of proteins onto a specialized region of cone cell surface (the plasma membrane template). Subsequent growth in Calpodes involves the appearance of a sponge-like scaffold which becomes packed with protein. In Onitis, newly synthesized protein fuses uniformly around the cone axis, giving rise to cross-sectional profiles which are at first starlike, then square, and finally circular.;A template membrane connecting the four cone cells is the initial site for the ordered deposition of cone protein. The structure of this template defines the limits and volume of the cone. Cone proteins will not fuse with other regions of the plasma membrane, and in the template\u27s absence form random aggregates. A template membrane fraction can be obtained from Calpodes by a two-step urea solubilization which leaves the template intact. It is associated with one 67kD isoform and with the 100kD polypeptide

Flow in near-critical fluids induced by shock and expansion waves

Abstract.: Unsteady shock and expansion waves are proposed as means to produce flows near the liquid-vapor critical-point without imposing pressure gradients. By choosing appropriate initial conditions and wave speeds, near-critical post-wave conditions can be obtained. The post-shock conditions are shown to be stable with respect to perturbations in the pre-shock conditions. The initial conditions are sufficiently far from the critical-point to allow fast thermal equilibration, permitting the use of larger fluid volumes. Example calculations for the cases of an impulsively accelerated piston, of a shock tube, and of a Ludwieg-like tube are presented yielding flows up to 20 m/s in sulfur hexafluoride (SF6), where the limit is due to the region of validity of the equation of state. The proposed setup also allows one to study shock wave propagation into near-critical fluid

The Abandoned Side of the Internet: Hijacking Internet Resources When Domain Names Expire

The vulnerability of the Internet has been demonstrated by prominent IP prefix hijacking events. Major outages such as the China Telecom incident in 2010 stimulate speculations about malicious intentions behind such anomalies. Surprisingly, almost all discussions in the current literature assume that hijacking incidents are enabled by the lack of security mechanisms in the inter-domain routing protocol BGP. In this paper, we discuss an attacker model that accounts for the hijacking of network ownership information stored in Regional Internet Registry (RIR) databases. We show that such threats emerge from abandoned Internet resources (e.g., IP address blocks, AS numbers). When DNS names expire, attackers gain the opportunity to take resource ownership by re-registering domain names that are referenced by corresponding RIR database objects. We argue that this kind of attack is more attractive than conventional hijacking, since the attacker can act in full anonymity on behalf of a victim. Despite corresponding incidents have been observed in the past, current detection techniques are not qualified to deal with these attacks. We show that they are feasible with very little effort, and analyze the risk potential of abandoned Internet resources for the European service region: our findings reveal that currently 73 /24 IP prefixes and 7 ASes are vulnerable to be stealthily abused. We discuss countermeasures and outline research directions towards preventive solutions.Comment: Final version for TMA 201

Atomistic phenomena in dense fluid shock waves

The shock structure problem is one of the classical problems of fluid mechanics and at least for non-reacting dilute gases it has been considered essentially solved. Here we present a few recent findings, to show that this is not the case. There are still new physical effects to be discovered provided that the numerical technique is general enough to not rule them out a priori. While the results have been obtained for dense fluids, some of the effects might also be observable for shocks in dilute gase