It is known that the 1-18 GHz Double Ridge Guide Horn (DRGH) antenna is highly sensitive to tolerances in manufacturing. Since a typical DRGH antenna is constructed from a number of individual parts, tolerances in the machining, even when numerically controlled, and errors in the assembly can easily lead to gaps between subsections. Performance deviations, most notably resonances in the boresight gain and VSWR was observed in a number of manufactured 1-18 GHz DRGH antennas. The exact cause of the performance deviations had to be determined in order to identify which sections of the antenna need to be redesigned in such a way that the effects of the manufacturing and assembling tolerances on the performance of typical mass produced DRGH antennas are reduced or eliminated. It was hypothesised that gaps most notable in the waveguide launcher section and especially the coaxial feeding section is the cause of the sharp resonance effects. This hypothesis was confirmed during the study. A highly accurate Method of Moments (MoM) numerical model of the 1-18 GHz DRGH antenna was developed, gaps were then implemented in between various parts of the model and the results observed. Based on these results a new improved 1-18 GHz DRGH antenna was designed with reduced sensitivity to manufacturing tolerances and improved performance. / Dit is alombekend dat die 1-18 GHz Dubbel Rif Golfleier Horing (DRGH) antenna baie sensitief is vir vervaardigings toleransies. 'n Tipiese DRGH antenna bestaan uit verskeie individuele onderdele. Toleransies in vervaardiging, selfs al word die proses numeries beheer, kan dus lei tot spasies tussen verskillende dele. Die waarneming van verswakte werkverrigting, meer spesifiek resonansies in die wins en Spannings Staande Golf Verhouding (SSGV) by 'n aantal vervaardigde 1-18 GHz DRGH antennes het gelei tot verdere studie. Om die 1-18 GHz ontwerp minder sensitief te maak ten opsigte van toleransies, moes die presiese oorsaak van die verswakte werkverrigting bepaal word. Aan die begin van die studie was die vermoede dat spasies in veral die golfleierlanseerder en meer spesifiek die koaksiale voer seksie, die oorsaak is van die resonansies. Die hipotese is in die daaropvolgende ondersoek bevestig. 'n Hoogs akkurate Metode van Momente (MvM) numeriese model is vir die 1-18 GHz DRGH antenna ontwikkel. Spasies is tussen verskeie parte van die model ge-inkorporeer en die resultate is ondersoek. 'n Nuwe verbeterde 1-18 GHz DRGH antenna op die ondersoek gebaseer, is ontwikkel. Die antenna het verminderde sensitiwiteit ten opsigte van vervaardigings toleransies sowel as verbeterde werkverrigting. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / Unrestricted

No description available.

Incarceration and sacculation of a retroflexed gravid uterus is relatively benign, in contrast with pregnancy in a rudimentary uterine horn which can lead to perforation and hemorrhage. We report a case of pregnancy in an incarcerated sacculated non‐communicating rudimentary horn mimicking incarceration with sacculation of a retroflexed gravid uterus. Both physical and sonographic findings were unhelpful in the differential diagnosis. Therefore, decision for laparotomy in such cases should be based on severity of symptoms.

The History of Horn Playing in Los Angeles from 1920 to 1970 begins with the horn players who played in the silent film orchestras and the Alfred Brain's tenure with the Los Angeles Philharmonic. This study details the introduction of soundtracks, the early studio orchestras, the contract studio orchestras, the musician union's role in structuring the work environment, the horn players who played in both the Los Angeles Philharmonic and the studios, major figures from the subsequent freelance period such as Vincent de Rosa, and the local and international influence of the Los Angeles Horn Club.

No description available.

No description available.

A preliminary experiment was conducted during the horn fly season at Blacksburg, Virginia from May through September, 1959, to determine the relationship of weather conditions to horn fly populations on 3 breeds of dairy heifers. Daily records of the fly populations on 10 animals selected at random from a mixed herd of Holstein, Guernsey, and Jersey yearling heifers were made. In addition, the daily minimum and maximum macrotemperatures and relative humidities, the approximate wind direction, and the amount of sunlight or cloud coverage were recorded. Usually there was a significant difference between the number of horn flies on Holstein and that on Guernsey and Jersey heifers. Horn flies generally preferred the dark colored areas of bicolored cattle during the hours of daylight, and they preferred the black of the Holstein rather than the tan of the Guernsey. When the macrotemperature was above 85°F, many of the flies were found on the white skin of the belly and udder area of a heifer. During inclement weather the flies were observed on both the white and dark colored areas of all the heifers. Macrotemperature and relative humidity influenced the horn fly populations within the biocenose. Light rain and winds of less than 20 miles per hour were found to have a negligible effect on the number of flies in the populations; however, significant population decreases were attributed to heavy rain, wind in excess of 20 miles per hour. Often, when the macrotemperature was below 55°F, light rain or wind of low velocity influenced movement of the flies to more sheltered areas on the host. The apparently preferred macroclimate for horn flies was: temperature of 73 to 80°F; relative macrohumidity of 65 to 90%; scattered light showers; and no wind. During the horn fly season of 1960, a second experiment was conducted to correlate the effect of the macro-environment on the micro-environment within the ½ inch mantle of the animal, and also to correlate the locations of horn flies within this mantle with various factors of the micro-environment. (Daily macro-environmental data, including air temperature, relative humidity, wind direction and velocity, amount of cloud coverage, and precipitation, were recorded as in the preliminary experiment of 1959.) Methods for measuring the micro-environment were devised, and the data obtained were analysed statistically and interpreted. Accordingly, the effects on horn fly populations of dark skin color, low temperature, and low humidity were highly significant at the 1% level; the effects on horn fly populations of high humidity and precipitation were significant at the 5% level; and the effect of high temperature on horn flies was not significant at the 5% level. According to the results of the second experiment, the horn flies apparently sought certain micro-environmental conditions which were most commonly observed on Holstein heifers. Within the mantle of micro-environment, horn flies appeared to prefer an air temperature of about 85°F, a skin temperature of about 97°F, and a relative humidity of about 65%. When such conditions were not available to the horn flies on the sides and backs of Holstein heifers, the flies usually found near optimum conditions along the belly midline for each of the 3 breeds of heifers. / Ph. D.

The effects of two different noise sources upon their surrounding communities were investigated with both quantitative and qualitative measures. A high school football game, which presents continuous noise over a relatively short duration on a predictable schedule was found to have a slight annoyance on its surrounding community. In contrast, a train horn blow at a residential intersection was investigated. This sound was unpredictable and could occur at any time. Residents in this community were found to have a moderate level of annoyance. It was found that each of the noises studied violated suggested noise levels for common household activities, in addition to many local, state, and federal noise regulations. It is recommended that both of the sounds studied herein be reduced or eliminated altogether. Limiting the level of sound produced by the PA system at the football game and using a noise reducing barrier would help in the case of the football game. Converting the railroad intersection into one with sufficient safety features, especially a crossing quad-gate that no longer requires trains to blow their horns would be the optimal solution, with the added benefit of precluding vehicles from entering the crossing when a train is present. / Master of Science

The purpose of this thesis is to analyze the use of alchemy within the work of Rebecca Horn, to elucidate its presence in her work, and to illuminate its purpose as a personal philosophy and as a creative tool. The use of alchemy within Horn's work occurs as a process of revelation and transformation. Alchemy is revealed as a spiritual philosophy and as an interpretative system through the changes that occur in Horn's oeuvre. Throughout Horn's career, alchemy has developed into an interpretive system, a type of spiritual and cosmic perspective, that allows the artist to study, access, and meld diverse realities (sacred and profane) and diverse social systems (religious and scientific) into a more holistic and spiritually infused reality for herself and society-at-large. The purpose of her work is to help reinvest contemporary life with a spiritual presence by offering a model and a means of bringing the sacred into the profane.

A work concerning the history of the Paris Conservatoire and music education in France. Follows the development of the horn and its correlation with the French school of horn playing. Includes biographic information on the horn professors of the Conservatoire through 1997, as well as a comprehensive list of the morceaux de concours for horn, 1795-1996.