International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / Shock and vibration testing was performed on the Metrum-Datatape Inc. 32HE recorder to determine its viability as an airborne instrumentation recorder. A secondary goal of the testing was to characterize the recorder operational shock and vibration envelope. Both flight testing and laboratory environmental testing of the recorder was performed to make these determinations. This paper addresses the laboratory portion of the shock and vibration testing and addresses the test methodology and rationale, test set-up, results, challenges, and lessons learned.

Coal mine impoundment failures have been well documented to occur due to an increase in excess pore pressure from sustained monotonic loads. Very few failures have ever occurred from dynamic loading events, such as earthquakes, and research has been done regarding the stability of these impoundment structures under such natural seismic loading events. To date no failures or damage have been reported from dynamic loading events caused by near-by production blasting, however little research has been done considering these conditions. Taking into account that current environmental restrictions oblige to increase the capacity of coal impoundments, thus increasing the hazard of such structures, it is necessary to evaluate the effects of near-by blasting on the stability of the impoundment structures. To study the behavior of excess pore pressure under blasting conditions, scaled simulations of blasting events were set inside a controlled sand tank. Simulated blasts were duplicated in both saturated and unsaturated conditions. Explosive charges were detonated within the sand tank at various distances to simulate different scaled distances. Information was collected from geophones for dry and saturated scenarios and additionally from pressure sensors under saturated conditions to assess the behavior of the material under blasting conditions.

Since the identi cation of proto-planetary nebulae (PPNe) as transition objects between the asymptotic giant branch stars and planetary nebulae more than two decades ago, astronomers have attempted to characterise these exciting objects. Today many questions still elude a conclusive answer, partly due to the sheer diversity observed within this small subset of stellar objects, and partly due to the low numbers detected. Fortunately, many of these objects display a rich spectrum of emission/absorption lines that can be used as diagnostics for these nebulae. This dissertation presents a study of six PPNe using the relatively new (at NIR wavelengths) integral eld spectroscopy technique. This method has allowed the investigation of distinct regions of these nebulae, and in certain cases the application of magneto-hydrodynamic shock models to the data. The goal of this research has been to investigate the evolution of PPNe by detailed examination of a small sample of objects consisting of a full range of evolutionary types. Near-IR ro-vibrational lines were employed as the primary tool to tackle this problem. In all six sources the 1!0S(1) line is used to map the spatial extent of the H2. In three of these objects the maps represent the rst images of their H2 emission nebulae. In the case of the earliest-type object (IRAS 14331-6435) in this sample, the line map gives the rst image of its nebula at any wavelength. In the only M-type object (OH 231.8+4.2) in the sample, high-velocity H2 is detected in discrete clumps along the edges of the bipolar out ow, while a possible ring of slower moving H2 is found around the equatorial region. This is the rst detection of H2 in such a late-type object but due its peculiarities, it is possibly not representative of what is expected of M-type objects. In IRAS 19500-1709, an intermediate-type object, the line map shows the H2 emission to originate in clumpy structures along the edges of a bipolar shell/out ow. The remaining three objects have all been the subject of previous studies but in each case new H2 lines are detected in this work along with other emission lines (Mg ii, Na i & CO). In the case of IRAS 16594-4656, MHD shock models have been used to determine the gas density and shock velocity. Two new python modules/classes have been written. The rst one to deal with the data cubes, extract ux measurements, rebin regions of interest, and produce line maps. The second class allows the easy calculation of many important parameters, for example, excitation temperatures, column density ratio values, extinction estimates from several line-pairs, column density values, and total mass of the H2. The class also allows the production of input les for the shock tting procedure, and simulated shocks for testing this tting process. A new framework to t NIR shock models to data has been developed, employing Monte Carlo techniques and the extensive computing cluster at the University of Hertfordshire (UH). This method builds on the approach used by many other authors, with the added advantages that this framework provides a method of correctly sampling the shock model parameter space, and providing error estimates on the model t. Using this approach, data from IRAS 16594-4656 have been successfully modelled using the shock models. A full description of this class of stellar objects from such a small sample is not possible due to their diverse nature. Although H2 was detected across the full spectral vi range of post-AGB objects, the phase at which H2 emission begins is still not clear. The only M-type object in this work is a peculiar object and may not be representative of a typical post-AGB star. The H2 PPNe appear to be located at lower Galactic latitudes (b 20 ) than the total PPNe population, possibly pointing to an above average mass and hence younger age of these objects.

Banks as the most evident financial institutions which provide a range of financial services in their primary role as intermediary from lenders and borrowers of money to sophisticated tools concerned with credit and liquidity provision, risk management and remittance of funds play a vital role in the economy of countries. Measuring the performance of banks, and identifying the factors which impact it, is an issue of major interest for regulators, policy makers, stakeholders, investors and the general public. Oil price movement as an external factor influencing the performance of banks, may affect macroeconomic events which, in turn, influence cash flows significantly in the finance and banking industry. Examining the performance of banks and how oil price movement impact their performance significantly those operating in oil exporting countries, is of interest of bank managers and policy makers. It will help top level managers of banks to be aware of relationship between oil price movement and the performance of their banks and will help them in formulating better policies and strategies in taking on opportunities and avoiding possible risks which this movement may cause. Moreover, it will help policy makers in oil exporting countries to understand how the banking industry of an oil exporting country can reap benefits from economic booms as a consequence of an increase in the price of oil. Therefore, this thesis attempts to investigate the impact of oil price movement on the performance of banks under different operational styles in oil exporting countries. The sample is consisting of 98 commercial, investment and Islamic banks in eight Middle Eastern oil exporting (MEOE) countries during the period 2000-2011. The research applies a two-stage Data Envelopment Analysis to examine the impact of oil price movement on performance of banks. In the first stage, four different efficiency scores of banks operating in the MEOE countries are derived and compared. The empirical results suggest that overall, MEOE banking industries mostly suffer from poor usage of and mal-location of resources by management to produce outputs, rather than a failure in operating at the most productive scale. A low level of overall technical efficiency in the MEOE banking industry means that management has poor skills in controlling operating expenses, marketing activities, absorbing deposits and the monitoring and effective screening of borrowers. In the second stage, to find out the impact of oil price movement on the performance of banks, technical efficiency scores obtained from the first stage are regressed over the oil price movement variable and environmental variables. The empirical results show that while oil revenue impacts the efficiency of the banks directly, positive oil price shocks impact efficiency of banks indirectly, and through inflation and economic growth. These findings suggest that when there is an increase in the price of oil, banks operating in oil exporting countries will derive benefit from the surplus income injected into the economy and their performance will be enhanced.

The commensal fungus, Candida albicans, can cause life-threatening infections in at risk individuals. C. albicans colonizes mucosal surfaces of most people, adhering to and interacting with epithelial cells. At low concentrations, C. albicans is not pathogenic nor does it cause epithelial cell damage in vitro; at high concentrations, C. albicans causes mucosal infections and kills epithelial cells in vitro. Here we show that while there are quantitative dose-dependent differences in exposed epithelial cell populations, these reflect a fundamental qualitative difference in host cell response to C. albicans. Using transcriptional profiling experiments and real time PCR, we found that wild-type C. albicans induce dose-dependent responses from a FaDu epithelial cell line. However, real time PCR and Western blot analysis using a high dose of various C. albicans strains demonstrated that these dose-dependent responses are associated with ability to promote host cell damage. Our studies support the idea that epithelial cells play a key role in the immune system by monitoring the microbial community at mucosal surfaces and initiating defensive responses when this community is dysfunctional. This places epithelial cells at a pivotal position in the interaction with C. albicans as epithelial cells themselves promote C. albicans stimulated damage.

Ultrasound contrast agents (CAs) are typically used in clinic for perfusion studies (blood flow through a specific region) and border delineating (differentiate borders between tissue structures) during cardiac imaging. The CAs used during ultrasound imaging usually consist of gas filled microbubbles (MBs) (diameter 1-5 μm) that are injected intravenously into the circulatory system. This thesis partially involves a novel polymer-shelled ultrasound CA that consists of air filled MBs stabilized by a polyvinyl alcohol (PVA) shell. These MBs could be coupled with superparamagnetic iron oxide nanoparticles (SPIONs) in order to serve as a combined CA for ultrasound and magnetic resonance imaging. The first three papers (Paper A-C) in this thesis investigate the structural characteristic and the elimination process of the CA. In Paper A, two types (PVA Type A and PVA Type B) of the novel CA were analyzed using transmission electron microscopy (TEM) images of thin sectioned MBs. The images demonstrated that the SPIONs were either attached to the PVA shell surface (PVA Type A) or embedded in the shell (PVA Type B). The average shell thickness of the MBs was determined in Paper B by introducing a model that calculated the shell thickness from TEM images of cross-sectioned MBs. The shell thickness of PVA Type A was determined to 651 nm, whereas the shell thickness of PVA Type B was calculated to 637 nm. In Paper C, a prolonged blood elimination time was obtained for PVA-shelled MBs compared to the lipid-shelled CA SonoVue used in clinic. In addition, TEM analyzed tissue sections showed that the PVA-shelled MBs were recognized by the macrophage system. However, structurally intact MBs were still found in the circulation 24 h post injection. These studies illustrate that the PVA-shelled MBs are stable and offer large chemical variability, which make them suitable as CA for multimodal imaging. This thesis also involves studies (Paper D-E) of the molecular chaperones (Hsp21 and DNAJB6). The small heat shock protein Hsp21 effectively protects other proteins from unfolding and aggregation during stress. This chaperone ability requires oligomerization of the protein. In Paper D, cryo-electron microscopy together with complementary structural methods, obtained a structure model which showed that the Hsp21 dodecamer (12-mer) is kept together by paired C-terminal interactions.The human protein DNAJB6 functions as a very efficient suppressor of polyglutamine (polyQ) and amyloid-β42 (Aβ42) aggregation. Aggregation of these peptides are associated with development of Huntington’s (polyQ) and Alzheimer’s (Aβ42) disease. In Paper E, a reconstructed map of this highly dynamic protein is presented, showing an oligomer with two-fold symmetry, indicating that the oligomers are assembled by two subunits. / <p>QC 20160527</p>

ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / A miniature 1 Watt Tactical Telemetry Module (TTM) has been developed for the Excalibur projectile program. The TTM incorporates a multi-channel PCM encoder, lower S-band transmitter, and power regulation onto a single printed wiring board (PWB). The PCM encoder is designed for eight (8) analog inputs, four (4) discrete inputs, and one (1) synchronous RS-422 serial interface, with a total data rate of 1 Mbps. The module incorporates a digitally programmable, phase-locked FM S-band transmitter. The transmitter utilizes M/A-COM’s new dual port VCO and a high efficiency 2 W power amplifier MMIC. Additionally, switching power regulation circuits were implemented within the module to provide maximum operating efficiency. This paper reviews the environmental requirements of Excalibur, the design of the Excalibur TTM, and presents electrical and air-gun test data.

Thesis (PhD (Industrial Engineering))--University of Stellenbosch, 2007. / Off-road working vehicles are subjected to high levels of vibration input on the rough terrain and irregular roads they work. The human operators are therefore exposed to high levels of whole body vibration (WBV) and at risk of developing health problems. A number of international standards address the matter of whole body vibration, and the European Union issued a directive which limits the exposure of workers in the EU to WBV. Unfortunately, to date there is no law in South Africa requiring compliance with any of these EU standards nor guidelines. There are vehicles which are not fitted with suspension and/or suspension seats. The three wheeled logger used in forestry is a highly manoeuvrable and effective bulk handler, but without any form of suspension and no space under the operator’s seat to install a suspension seat. However, a suspension cushion can be retrofitted to existing vehicles largely alleviating the problem. To isolate low frequency vibration large suspension travel is required which makes an air suspension cushion attractive, as it can fully collapse. Additionally, a Helmholtz resonator if added to the cushion in the form of a pipe and tank, provides anti-resonance at a specific frequency. The resonator can be tuned by adjusting the pipe’s length and diameter as well as the volume of the tank. Larger diameter pipes have less friction and give better reduction of the transmissibility curve at the anti-resonance frequency. The SEAT value is a single number used to compare suspension seats for a specific input vibration. It is calculated from the weighted input acceleration power spectral density curve and the suspension seat transmissibility curve. The former is obtained from the vehicle and is vehicle, path and speed dependent. The latter is the only variable that can be improved by using a better suspension seat/cushion. The input power spectral density often contains significant energy at frequencies where the human operator is most sensitive. The cushion resonator could be tuned to position the anti-resonance in the transmissibility curve at these frequencies. The resultant output vibration would thus be lower than the input vibration at that frequency. In this dissertation an analytical model describes the state variables in the cushion, pipe and tank. A Simulink model predicts the transmissibility curve with a solid mass as well as with a two degree of freedom seated human model. Initially the prototype was tested with a solid mass to compare the transmissibility curve produced by the simulation with the experimental results. It was required to evaluate the contribution of the resonator without the complexity of the human impedance. Subsequent tests were carried out with human subjects. Test results showed high inter subject similarity at the anti-resonance frequencies. Design guidelines are formulated that can be used by the suspension cushion designer to specify the pipe diameter and length and the volume of the tank to determine the optimal transmissibility. Input psd from ISO7096 class EM3 vehicles is used as an example during the design process. A prototype air suspension cushion was designed to reduce output vibration on the three wheeled logger. Laboratory tests with human subjects showed a significant improvement at the problematic frequencies through the tuning of the resonator. Using a Helmholtz resonator with the air suspension cushion the overall SEAT value improved by 25% compared with a 100mm foam cushion. However, the current tank and pipe need to be reduced in size for practical implementation to the vehicle. Future work would include finding an alternative mass to replace the air in the pipe. This should reduce the size of the tank and the pipe required. Additionally the simultaneous effect of multiple resonators at different frequencies should be investigated. This is required for vehicles having an input psd with significant energy at more than one frequency band.

The initial public offering (IPO) underpricing phenomenon has frequently been noticed and generally is accepted as a puzzle in financial economics. Some of the new theories, such as behavioural finance, take the underpricing puzzle as one important form of evidence. However, some aspects of IPO underpricing have not yet been fully documented and discussed in the existing literature. This thesis tries to contribute in the following three specific areas. First, we focus on the time series properties of the level of underpricing of IPO shares and document the IPO market in the Hong Kong market from 1999 to 2005. In the data sample, strong autocorrelation within the level of underpricing has been discovered. Evidence suggests the initial selling volume plays an important role in the relationship. The links between underpricing and clustering of IPOs within different industries are weak, suggesting the reasons for underpricing are related to the market liquidity rather than to the industry-specific risk characteristics. Second, we investigate the underwriting networks to explore the relationship between underwriting business and IPO related puzzles. We find that in repeated IPOs, underwriters build up reputation and accumulate knowledge of their underwriting services. One of the great advantages of the top ranked underwriters is their relationship networks with other underwriters and institutional investors. We perform a careful examination of the underwriter syndicate and investigate the relationship of the structure of the syndicate in respect of IPO performance. Moreover, the pattern of distribution in the size of syndicates is identified and is found to be significantly related to the IPO performance. The research shows that the perspective from the underwriter syndicate is not only interesting, also necessary to understand IPOs. Third, we analyse the coordination problem in the IPO. In the research, we consider the auction method as a one-stage selling and the bookbuilding method as a two-stage selling method. The model suggests that the relationship between the underpricing level and the quality of IPO shares is non-monotone. This implication is consistent with empirical observations. In addition, regarding the issuers' proceeds in the IPOs, the auction method is better than the bookbuilding method in both noisy and noisy vanishing equilibria. The bookbuilding method may be helpful in other ways, such as maintaining liquidity or price support in secondary market. By studying liquidity, business networks and the coordination problem, the thesis does not only complement the existing research by providing unique explanations for the IPO underpricing and other related puzzles, but also opens some interesting venues for future research.

published_or_final_version / Physiology / Doctoral / Doctor of Philosophy