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Surface air pressure differentials that occur over reservoirs, canals, and water-catchment aprons in high-wind conditions were determined by the use of models in a wind tunnel. Such information was needed concerning the magnitude and location of destructive wind forces on water barriers constructed of exposed flexible membrane liners. Rigid models, without a membrane, were used to measure airpressure differentials. Air-pressure differentials were dependent on geometric configuration and were independent of viccous forces above the critical Reynolds number which was determined experimentally. The geometric factors studied with respect to reservoirs and canals included approach slope, approach slope length, leeward slope, and breadth-depth ratio. Those pertaining to water-catchment aprons included breadth-berm height ratio and berm shape. On the leeward slope of reservoirs, favorable (positive) differential pressures were more apt to occur as the approach and leeward slopes decreased (became less steep), but extreme adverse (negative) pressures occurred under the same conditions near the top edge of the slope. As the leeward slope increased the pressure coefficient values were essentially constant over the entire surface. On the reservoir bottom, adverse pressures did not exist when approach and leeward slopes were at the minimum evaluated (1:4). When the leeward and approach slopes increased the average pressure on the bottom became less favorable. The most adverse pressure coefficients generally occurred at the toe of the leeward slope, while maximum favorable pressures on the reservoir bottom generally occurred at the toe of the downwind slope. In most instances, the pressure on the downwind slope was favorable; however, adverse pressures were recorded near the top edge of the slope. These adverse or negative pressure conditions were more apt to occur as the breadth-depth ratio increased and the leeward slope decreased. Average pressure values on the interior surface of canals were generally less adverse than for reservoirs. Similar to the reservoirs, the most adverse pressures on the leeward slope of the canals were found immediately over the upper edge of the slope. Extreme adverse pressures on the canal bottom were associated with long and steep approach slope conditions. One exception was the occurrence of the most favorable pressure over the canal bottom when the approach slope was short but still steep. In addition to measurement of adverse pressures near the top edge of the downwind slope, adverse pressures were found near the toe of the slope in some instances. The portion of the downwind slope under an adverse pressure influence decreased as the breadth-depth ratio increased. Generally, pressures over a canal were more responsive to the approach slope and approach slope height than to leeward slope arid breadth-depth ratio. For a reservoir, however, pressures were responsive to all geometric factors, depending on which section of the reservoir was being considered. Pressure distributions over water-catchment aprons were independent of breadth-berm height ratios of 50 or greater. Negative pressures were lower over gradual sloped catchment berms by a factor of three than over sine-shaped berms. Each berm shape, on the leeward side of the upwind berm, had a pressure distribution associated with it that was the same as far as shape but was different in magnitude depending on the shape of the windward side of the berm. Pressures were less adverse on the leeward side of the berm, if the windward side were gradually sloped. Pressures were near zero to slightly favorable over a large portion of the water-catchment apron between the berm toes. This near stable favorable condition might change significantly, if site conditions were to change.

The key goal of the following diploma thesis is to evaluate influence of the air pressure in the car tires on the driving dynamic, stability and comfort. The first part is dedicated to the theory of the driving dynamic, stability, tire parameters and tire inflation. Next practical part is focused on the drivers’ knowledge about the correct tire inflation and follows with the measurements and evaluation of the influence of the tire inflation on the driving characteristics, riding comfort and its comparison. These influences are summarized and followed up by the recommendations for the drivers and also the expert activities.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 195-202).

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009. / Härtill 4 uppsatser.

Vocal fold vibration results from an alternating balance between subglottal air pressure that drives the vocal folds apart and muscular, elastic, and restoring forces that draw them together. The aim of the present thesis is to present quantitative data of normal vocal function using a noninvasive method. Measurements are made on the inverse filtered airflow waveform, of estimated average trans glottal pressure and glottal airflow, and of sound pressure for productions of syllable sequences. Statistical results are used to infer mechanisms that underlie differences across ( 1 ) normal, loud, and soft voice, (2) normal, high, and low pitch, and (3) between female and male voices. Interspeaker variation in group data and intra speaker variation across repeated recordings is also investigated. The results showed no significant female-male differences in pressure, suggesting that differences in other measures were not primarily due to differences in the respiratory systems . Most glottal waveforms showed a DC flow offset, suggesting an air leakage through a posterior glottal opening. Results suggested (indirectly) that the males in comparison with the females had significantly higher vocal fold closing velocities (maximum flow declination rate), larger vocal fold oscillations (AC flow), and relatively longer closed portions of the cycle (open quotient) in normal and loud voice. In soft voice, female and male waveforms were more alike. In comparison with normal voice, both females and males produced loud voice with significantly higher values of pressure, vocal fold closing velocity, and AC flow. Soft voice was produced with significantly lower values of these measures and increased DC flow. Correlation analyses indicated that several of the airflow measures were more directly related to vocal intensity than to pitch. Interspeaker variation was large, emphasizing the importance of large subject groups to capture normal variation. Intraspeaker variation across recording sessions was less than 2 standard deviations of the group means. The results should contribute to the understanding of normal voice function, and should be useful as norms in studies of voices disorders as well. / Härtill 5 uppsatser.För att köpa boken skicka en beställning till exp@ling.su.se/ To order the book send an e-mail to exp@ling.su.se

This diploma thesis focuses on incorrect inflation and incorrect use of tires in extreme situations. In the first part, a search of previously created works is reported. This is followed by the elaboration of the basic theory, which describes the driving dynamics of the vehicle, braking and construction, marking, wear and inflation of tires. The next part is the measurement and evaluation of the effect of incorrect inflation and use of tires. Braking deceleration and evasive maneuvers were performed as tests. The third part is an evaluation and summary of the situation.

Boost Treadmills™, a company specializing in the use of differential air-pressure (DAP) technology in the realm of exercise and rehabilitation, is developing their second-generation micro-gravity treadmill™ named the Boost 2. This machine will allow individuals in all types of fitness environments to move and exercise at a fraction of their normal body weight, reducing the impact forces on lower body extremities and allowing for accelerated returns to activity. The purpose of this thesis was to create an algorithm to be implemented on the Boost 2 that related the percentage of body weight reduction of a user to a required pressure value within the Boost 2 pressure differential space created by the enclosure. This algorithm, when implemented, would allow a Boost 2 user to simply operate the machine at the appropriate pressure(s) automatically by entering their Boost shorts size, approximate height, and desired percentage of body weight reduction from a previously developed user interface screen. The calibration algorithm was developed using collected data and a regression analysis model created in Microsoft Excel®. This analysis creates an equation for a linear fit of predictor variables resulting in a line representing the body weight reduction pattern of a user as pressure is increased within the enclosure. On average, the difference between measured and predicted body weight percentages at measured pressure values was found to be less than 3%.

Driver sleepiness is known to be a major contributor to road traffic incidents (RTIs). An initial literature review identified many studies reporting untreated obstructive sleep apnoea (OSA) sufferers as having impaired driving performance and increased RTI risk. It is consistently reported that treatment with continuous positive air pressure (CPAP) improves driving performance and decreases RTI risk, although most of these studies are conducted less than one year after starting treatment. UK law allows treated OSA patients to continue driving if their doctor states that treatment has been successful. Despite the wealth of publications surrounding OSA and driving, 6 key areas were identified from the literature review as not fully investigated, the: (i) prevalence of undiagnosed OSA in heavy goods vehicle (HGV) drivers in the UK; (ii) impact of sleep restriction on long term CPAP treated OSA compared with healthy controls; (iii) ability of treated OSA participants to identify sleepiness when driving; (iv) impact of one night CPAP withdrawal on driving performance; (v) individual difference in driving performance of long term CPAP treated OSA participants; (vi) choice of countermeasures to driver sleepiness by two groups susceptible to driver sleepiness, OSA and HGV drivers. Key areas (i) and (vi) were assessed using questionnaires. 148 HGV drivers were surveyed to assess OSA symptoms and preference of countermeasures to driver sleepiness. All participants completing the driving simulator study were also surveyed. 9.5% of HGV drivers were found to have symptoms of suspected undiagnosed OSA. Additionally the OSA risk factors were more prevalent for HGV drivers than reported in national statistics reports for the general population. The most effective countermeasures to driver sleepiness (caffeine and a nap) were not the most popular. Being part of a susceptible group (OSA or HGV driver) and prior experience of driver sleepiness did not promote effective choice of countermeasure. Key areas (ii) to (v) were assessed using a driving simulator. Driving simulators present a safe environment to test participants in a scenario where they may experience sleepiness without endangering other road users.

För att skapa konkurrenskraft krävs alltid optimering, av flera olika processer, mot mer energi- och kostnads-effektivitet. Anläggningen som används i detta projekt, ett kraftvärmeverk som byggdes så sent som 2015, har dragits med vad som verkat vara en icke optimal drift av tryckluftssystemet med tre identiska, frekvensomformarstyrda kompressorer. Målsättningen med detta projekt var att ta fram förslag på en mer optimal styrning av anläggningens tre kompressorer samt att implementera den för att genomföra en analys om resultatet. En nulägesanalys visade att det fanns utrymme för förbättring av styrningen samt att en del regulatorparametrar skulle behöva optimeras. Två regleringsförslag togs fram, som till stor del vara ganska lika men med den stora skillnaden att förslag ett använda sig av kompressorernas tryckregulatorer och det andra förslaget styrde kompressorernas varvtal direkt från PLC:n. I slutet på detta projektet, när de nya regleringsförslagen skulle implementeras, var anläggningen i ett tre veckor långt driftstopp för underhåll. Detta påverkade optimeringen genom att förbrukningen av tryckluft var låg. Detta skulle lett till att en parameteroptimering inte skulle blivit helt optimal. Eftersom kompressortillverkaren inte valde att samarbeta fanns dessutom ingen möjlighet att utföra en parameteroptimering på alla regulatorer. Trots dessa omständigheter så har en viss optimering troligen skett med det nya regleringsförslaget. / In order to create competitiveness, optimization towards more energy and cost efficiency is always required, of several different processes. The plant used in this project, a cogeneration plant that was built as late as 2015, has been drawn with what appeared to be a non-optimal operation of the compressed air system with three identical air compressors whom are controlled by frequency converters. The objective of this project was to produce proposals for a more optimal control of the plant's three air compressors and to implement it to carry out an analysis of the result. An analysis of the origin operation showed that there was room for improvement of the control and that some controller parameters would need to be optimized. Two regulatory proposals were developed, which to a large extent are quite similar but with the great difference that the first proposal make use of the compressors' pressure controllers and the other proposal controlled the speed of the compressors directly from the PLC. At the end of this project, when the new regulatory proposals were to be implemented, the facility was in a three-week downtime for maintenance. This affected the optimization because the consumption of compressed air was low. This would mean that a parameter optimization would not be completely optimal. Moreover, since the compressor manufacturer did not choose to cooperate, there was no possibility of performing a parameter optimization on all controllers. Despite these circumstances, some optimization has probably occurred with the new regulatory proposal.