No description available.

The pulse technique was employed to measure velocities of longitudinal and transverse mechanical waves in solid iodine at ultrasonic frequencies. Pulses were produced and their echoes displayed by a Sperry Ultrasonic Attenuator Comparator. Transducers for generating the waves were: longitudinal waves, X-cut quartz crystals of 5 and 12 Mcs.; transverse waves, Y-cut quartz crystal of. 5 Mcs. For longitudinal measurements the sample was immersed in baths of liquid helium, liquid nitrogen, solid carbon dioxide, ice, ambient room temperature, and boiling water. No dispersion was found. Four samples were used, but as iodine is anisotropic in many of its physical properties most attention was paid to two amorphous samples which were thought to give representative average values of the properties of iodine. From the values of longitudinal velocity, Young's modulus was calculated. Transverse velocity measurements were made in baths of liquid helium, liquid nitrogen, carbon dioxide, and ambient room temperature. The shear, modulus was determined from the transverse velocity; compressibility was found from Young's modulus and the shear modulus. All these quantities behave much as would be expected of a solid material. The Debye characteristic temperature calculated from the longitudinal and transverse velocities was compared with values calculated from specific heat data and Lindemann melting point formula. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Gasoline is a complex fuel containing hundreds of species, and, therefore, it is quite difficult to model all components present in gasoline. Alternatively, researchers tend to employ simpler surrogates that mimic targeted physical and chemical properties of gasoline. Two properties of gasoline, i.e., autoignition and laminar flame speed, play key role in the overall performance of spark-ignition and modern engines. For fuel-engine optimization, it is very important to have simple models which can accurately predict autoignition and laminar flame speed of gasoline. In this work, universal laminar flame speed correlation is proposed for typical gasolines. This correlation is based on Monte-Carlo simulations of randomly generated mixtures comprising of 21 gasoline-relevant molecules. Laminar flame speed of each molecule is numerically computed over a wide range of thermodynamic conditions using detailed chemical kinetic models, while flame speed of each mixture is estimated using a mixing rule. The proposed universal correlation is validated against experimentally-measured laminar flame speed of various gasoline fuels.

"Winds aloft are normally determined from the horizontal projection of an ascending balloon's path on a polar diagram. This method obtains a value for the average wind speed and direction for the layer through which the balloon has ascended during a two-minute interval by drawing a straight line between the horizontal projection of the balloon's position at the beginning and end of the two-minute interval. The horizontal projection of a balloon's actual path is a smooth curve and it is believed that a more accurate measurement of the average wind speed and direction for the layer will be obtained by determining the wind speed from the length of the curve for the two-minute interval and determining the direction from the tangent to the balloon's position along the curve at the intermediate time interval. The wind speed was computed by both methods for three months' data and the results compared with the purpose of determining a correction factor. The wind direction as determined by the method suggested was found not to vary appreciably from the direction determined by the conventional method. It was found that there is often a considerable difference in the wind speed as determined by the two methods especially at very low wind speeds, with the wind speed determined by the conventional method always being too small, but that it is impractical to apply a correction factor to reported winds when one considers the absolute value, rather than the percentual value, of the difference"--Abstract. / Typescript. / "August, 1956." / "Submitted to the Graduate Council of Florida State University in partial fulfillment of the requirements for the degree of Master of Science." / Includes bibliographical references (leaf 16).

A relatively new method of measuring local velocity in a fluid stream has been devised which eliminates some of the inherent problems of the traditional methods. This method senses the Doppler shift of light scattered from a laser beam incident on particles suspended in the fluid. The Doppler shift is proportional to the particles (or fluid) velocity. This new technique has several distinct advantages over the more traditional methods of velocity measurement.

<p> The perception of animacy - judging an object as appearing alive - is a fundamental social perception dating back to Piaget. The present research investigates motion to examine how and when people will perceive an ambiguous moving object as appearing alive.</p> <p> Chapter 1 uses a number of methods to illustrate that people will judge a relatively faster-moving object as appearing alive more often than an identical but relatively slower-moving object. Chapter 2 demonstrates that people are more likely to perceive an object moving at a constant speed if it appears to move relatively faster than a similar object. Further, people will make this judgement even if the differences in speed are not real, but merely illusory.</p> <p> Chapter 3 describes a specific case where the association of greater speed and animacy is not perceptually maintained. By showing people objects that appear to fall or rise - thereby obeying or violating gravity - it is shown that our perceptions of animacy are not fixed, but rather are functionally adapted to at least one regular and predictable feature of the visual environment; namely gravity. This suggests that some aspects of our perceptions of animacy have been shaped over evolutionary time.</p> <p> The following chapter examines whether our perceptions of animacy are structured - like our perceptions of colours - categorically, such that there is an identifiable boundary between the velocities that elicit a perception of animacy and the velocities that do not. Results suggest that people do not perceive animacy categorically</p> <p> The final empirical chapter illustrates that experience over the lifespan also influences our perceptions of animacy and of speed. Monolingual readers of a language read from left-to-right (viz., English) were biased to judge an object moving in that direction as appearing faster and more alive than an object moving at the same speed in the opposite direction. However, bilingual readers of both English and a language read from right-to-left did not exhibit this bias.</p> / Thesis / Doctor of Philosophy (PhD)

No description available.

The focus of highway work is shifting from new construction further into maintenance, rehabilitation, and reconstruction of existing facilities. Work zones constitute sections of highway where these efforts are actively pursued. Excessive speed is often a contributing factor to work zone accidents. One method of speed control in work zones is the deployment of unmanned, or drone, radar transmitters, to simulate and supplement police presence in work zones. A review of the literature and past research on speed control techniques was conducted, and data was collected in several work zones on Interstate 81 in Virginia. Traffic data were gathered both upstream and in the range of the unmanned radar units. Effectiveness of the unmanned radar was expressed as changes in mean speed, speed variance, percent of traffic exceeding the speed limit, and eighty-fifth percentile speed. Statistical analyses on the resulting speed distributions utilized hypothesis testing to determine the significance of differences in the measures of effectiveness among speed control conditions in work zones. User costs associated with work zones were also examined. At the sites studied, significant reductions in mean speed and in percent of traffic exceeding the speed limit were observed, as were minor reductions in speed variance and eighty-fifth percentile speed. Unmanned radar was found to be particularly effective when police presence was expected by motorists. From this research effort, recommendations were developed to assist traffic engineers in determining the most effective way to use unmanned radar to maximize their safety benefit on the traffic stream. / Master of Science

Low speed urban streets are designed to provide both access and mobility, and accommodate multiple road users, such as bicyclists and pedestrians. However, speeds on these facilities often exceed the intended operating speeds as well as their design speeds. Several studies have indicated that the design speed concept, as implemented in the roadway design process in the United States, does not guarantee a consistent alignment that promotes uniform operating speeds less than design speeds. To overcome these apparent shortfalls of the design speed approach, a promising design approach is a performance-based design procedure with the incorporation of operating speeds. Under this procedure, the geometric parameters of the roadways are selected based on their influences on the desired operating speeds. However, this approach requires a clear understanding of the relationships between operating speeds and various road environments. Although numerous studies have developed operating speed models, most of these previous studies have concentrated on high speed rural two-lane highways. In contrast, highway designers and planners have very little information regarding the influence of low speed urban street environments on drivers' speeds. This dissertation investigated the relationship between drivers' speed choices and their associated low speed urban roadway environments by analyzing second-by-second in-vehicle GPS data from over 200 randomly selected vehicles in the Atlanta, Georgia area. The author developed operating speed models for low speed urban street segments based on roadway alignment, cross-section characteristics, roadside features, and adjacent land uses. The author found the number of lanes per direction of travel had the most significant influence on drivers' speeds on urban streets. Other significant variables include on-street parking, sidewalk presence, roadside object density and offset, T-intersection and driveway density, raised curb, and adjacent land use. The results of this research effort can help highway designers and planners better understand expected operating speeds when they design and evaluate low speed urban roadways.

The diploma thesis deals with the issue of driver´s subjective estimation of vehicle speed and at the same time it is a project dealing with acquisition and evaluation of data obtained during the driving tests. The perceived vehicle speed is examined from the perspective of a driver - the respondent, who has no possibility of controlling the actual vehicle speed on the vehicle's speedometer. The aim is to either confirm or refute whether the driver is able to adequately estimate the speed of a moving vehicle in the event of an accident as well as describe the factors that may affect a subjective estimation of the driver's speed.