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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Species visitation at free-choice quail feeders in west Texas

Henson, Kelly Diane 16 August 2006 (has links)
Providing supplemental feed is a popular management practice for quail (northern bobwhite Colinus virginianus and scaled quail Callipepla squamata ) in Texas. It is common knowledge that non-target species, e.g., raccoons (Procyon lotor), are frequent visitors at feeding stations intended for quail. However, empirical data are scarce on seasonal visitation rates at such feeders, either by quail or by non-target species. The ecological efficacy and economic efficiency of a feeding program for quail depends on several variables; perhaps the most important of these is how much of the feed is consumed by quail versus various non-target species. I monitored species visitation seasonally at free-choice quail feeders with motion-sensing cameras at 4 sites in West Texas (Coke, Fisher and Stonewall counties). Quail feeders were monitored using active-infrared sensing camera systems and passive-infrared video systems, to compare data obtained via these 2 surveillance techniques. I tested 2 research hypotheses: 1) that quail feeders are visited by a wide range of non-target species; and 2) active-infrared surveillance will yield a more precise estimate of species visitation than estimates derived from passive video surveillance. Major findings included documentation of approximately 14 mammalian and 18 avian species that were recorded in a total of 6,558 events. Data analysis yielded a chronology of feeding behavior by all visiting species. I found that species visitation at quail feeders varied according to season, with the greatest number of events occurring during the fall and the fewest during the winter. Feeder visitation also varied according to lunar phase, with the fewest events occurring during the new moon phase. I recorded the duration of each event monitored on videotape, a total of 29,235 minutes, and determined that feeder visitation by raccoons comprised 43.2% of all time spent at quail feeders across all species. Visitation by bobwhite and scaled quail comprised only 5.4% of time spent at quail feeders by all visiting species. This study confirmed the need for strategy implementation that minimizes non-target consumption of feed intended for quail.
2

Management, Sanitation, and Accuracy of Automated Calf Feeders

Dietrich, Alyssa 23 July 2015 (has links)
The objective was to summarize management practices, identify factors associated with bacterial counts, and describe the variation in total solids concentrations of milk or milk replacer in automated feeders. Six dairy calf operations in Virginia and 4 in Minnesota employing 1 to 2 sophisticated automated calf feeders were visited biweekly for 26 to 28 wk. An initial management survey was conducted for each farm. Observations on facilities, calf weights and heights, blood samples to estimate serum total proteins, treatment records, digital feeding behavior records, and milk or milk replacer (MMR) samples were collected at each visit. Additional milk replacer (MR) samples were collected for 4 wk pre- and post-circuit cleaning. Samples of MMR were plated on Aerobic Plate Count (APC) and Coliform Count (CCP) Petrifilms. Total solids concentration was estimated for MR samples by refractometry. Feeding plans varied widely between farms. Estimates of calf growth were near industry standards, but the proportion of calves receiving treatment was elevated. Least squares mean APC and CCP were 5.26 and 3.01 log10 cfu/ml for Virginia and 3.80 and 0.61 log10 cfu/ml for Minnesota. Circuit cleaning (CC) caused 13 and 16% log reduction in APC and CCP. However, more frequent CC/wk increased bacteria. Mixer/heat exchanger cleanings decreased bacteria during biweekly farm visits. Chlorine bleach reduced bacteria. Use of silicone feeder hoses increased bacteria. A quadratic effect of MMR liters delivered/d was observed; liters delivered > 147 L decreased APC. Automated feeders delivered 12.26% of MR samples > 2% over and 25.71% > 2% under target solids concentration. / Master of Science
3

Feeding ecology of birds in a Mist Belt forest in South Africa

Scott, Samantha Luise 06 March 2013 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science October 2012 Johannesburg, South Africa / Food is not always readily available and therefore an important limiting resource to birds. South African forests have a similar fruiting and flowering phenology to tropical forests in that food availability fluctuates over space and time. South African indigenous forest is naturally fragmented in a non-forest matrix and therefore differs from tropical forests. Anthropogenic landuse change has contributed to the increased fragmentation of indigenous forest. The isolated nature of patches provides a suitable platform from which to assess changes in a forest bird community between seasons because they are structurally and functionally distinct from the surrounding vegetation. Therefore, the aim of the study was to assess food as a driver of community dynamics and dietary patterns of birds in a Mist Belt Mixed Podocarpus forest patch between two distinct seasons, winter and summer. This was assessed through a combination of field techniques and stable isotope analysis of carbon and nitrogen. Further, birds were categorised as forest specialists, forest generalists, and forest visitors based on published information to provide extra insight into community changes. Species richness and abundance differed between seasons due to the local movements and turnover of birds and due to the influx of migrants into the forest. In addition, nectarivores and frugivores increased in abundance and biomass in the forest in winter when flowers and fruit were readily available from canopy trees, such as Halleria lucida and Podocarpus latifolius. However, insect-eating guilds increased in summer when there was a greater diversity of invertebrates. Nectarivores, granivores, and omnivores vertically tracked food within forest height strat to where it was most abundant, demonstrating a close association with the location of their food resources. Further, the niche of several species, particularly insectivores and nectarivores, broadened in winter when food resources were limited. However, there was niche contraction in several bird species in summer when resources were more readily available. Overall, the forest acted as a refuge for guilds, particularly frugivores and nectarivores, in winter. Furthermore, this study suggested that food limitation is species-specific and does not apply to all species. Understanding the drivers of community change has important implications for forest management and conservation of forest flora and fauna.
4

Management factors affecting calf growth and health

Machado, Kayla L. 20 January 2012 (has links)
Two calf feeding trends are emerging in the dairy industry in the United States. Large herds often find it economical to feed pasteurized waste milk; while smaller herds are embracing technological advancements by utilizing automated calf milk feeders. Housing of calves varies depending on feeding mechanism. Calves fed using autofeeders are grouped together but large herds often find it more labor efficient to house calves individually in elevated wooden crates or polyethylene hutches. Two studies were conducted. The objective of the first field study was to evaluate the influence of diet and housing type on growth and morbidity in 84 Holstein heifer calves in a 2 by 2 factorial experimental design. Calves were housed in either polyethylene hutches or elevated wooden crates with slatted floors. Diets consisted of pasteurized waste milk or the same waste milk supplemented to provide approximately 454 g of milk replacer solids containing 25% protein and 10% fat (LOL Balancer). Calves were randomly placed in 1 of 4 treatment groups 48 h after birth and monitored until weaning (~60 d of age). Body weights and hip heights were measured at time of enrollment and weaning. Milk samples of pasteurized waste milk were obtained five times weekly to measure standard bacteriological plate count, fat, protein and total solids content. All calves were fed 3.3 L of liquid diet via bottle at 0730 and 1530 h. Calves were monitored daily for respiratory and digestive illness and treated according to established protocols. Pasteurized waste milk contained 332,171 ° 733,487 cfu/ mL, 3.51 ° 0.59% fat, 3.13 ° 0.30% protein, and 11.64 ° 1.05% total solids. Housing (P = 0.02) and diet (P = 0.01) affected weight gain, but there was no interaction. Least squares average daily gain for crate and hutches were 0.52 ° 0.024 and 0.59 ° 0.024 kg/d. Least squares average daily gain for waste milk and balancer diets were 0.52 ° 0.024 and 0.60 ° 0.024 kg/d, respectively. Housing or diet did not affect hip height growth/d (0.196 ° 0.007 cm). Health of the calves was not affected by diet or housing. Supplementing waste milk with balancer or housing calves in hutches resulted in higher weight gain. The objective of the second study was to evaluate management, and sanitation and consistency of liquid delivered to calves via automated feeders. Ten herds in Virginia and North Carolina with sophisticated (Förster-Technik, Germany) and basic (Biotic Industries Inc., TN, USA) machines completed a 60-question survey concerning calf and autofeeder management. Duplicate milk replacer samples were obtained to measure sanitation, dry matter, and temperature of milk in the autofeeder at the time of the survey. Six dairies from the original 10 were visited monthly for 3 mo for continued evaluation of sanitation, dry matter, and temperature of milk replacer from the autofeeder. Seven herds utilizing basic machines had a mean SPC of 6,925,000 ° 7,371,000 cfu/ml. The mean dry matter and temperature readings were 12.0 ° 2.1 Brix and 38.8 ° 6.7 °C, respectively. Three dairies that used sophisticated autofeeders had a mean SPC of 1,339,000 ° 2,203,000 cfu/ml. Mean dry matter and temperature readings were 10.37 ° 1.68 Brix and 38.6 ° 6.76°C, respectively. Dairies were also categorized based on management strategies. Producers that purchased autofeeders to manipulate feeding rates, refocus labor to sanitation, and care and well-being of calves, or for technological advancements were successful at rearing calves via autofeeders. Dairy producers who purchased an autofeeder to explore feeding options were not as successful because proper time and management was not dedicated to care of calves or to maintenance of the autofeeder. / Master of Science
5

A New Approach to Mitigate the Impact of Distributed Generation on the Overcurrent Protection Scheme of Radial Distribution Feeders

Funmilayo, Hamed 14 January 2010 (has links)
Increased Distributed Generation (DG) presence on radial distribution feeders is becoming a common trend. The existing Overcurrent Protection (OCP) scheme on such feeders consists mainly of overcurrent protection devices (OCPDs) such as fuses and reclosers. When DG is placed on the remote end of a 3-phase lateral, the radial configuration of the feeder is lost. As a result, OCP issues may arise which lead to permanent outages even when the fault is temporary. This thesis presents a new approach that revises the existing OCP scheme of a radial feeder to address the presence of DG. The fuses on the laterals with DGs are removed and multifunction recloser/relays (MFRs) are added to address three specific OCP issues; fuse fatigue, nuisance fuse blowing, and fuse misoperation. The new approach requires no communication medium, provides backup protection for the DG unit, and allows the remaining laterals to retain their existing protective devices. The results are reported using the IEEE 34 node radial test feeder to validate the new approach and the IEEE 123 node radial test feeder to generalize the approach. The new approach completely mitigated the fuse misoperation and nuisance fuse blowing issues and most of the fuse fatigue issues that were present on the radial test feeders. Specifically, the approach demonstrates that coordination between the existing protection devices on radial distribution feeders is maintained in the presence of DG.
6

Análise das correntes transitórias de inrush em redes de distribuição. / Inrush current transients analysis in distribution feeders.

Souza, Hamilton Guilherme Bueno de 01 June 2007 (has links)
O presente trabalho tem como objetivo analisar as correntes de inrush que surgem nos momentos de energização dos alimentadores de sistemas de distribuição. Desta forma, são relevantes em projetos cotidianos de concessionárias de energia elétrica como por exemplo, nos cálculos de ajustes dos dispositivos de proteção. Foram estudadas 291 (duzentas e noventa e uma) amostras extraídas de oscilografias de medidores alocados nas saídas de alimentadores de distribuição, os quais armazenaram informações de tais correntes nos momentos em que houveram religamentos bem sucedidos (carga quente), bem como em energizações após longos períodos de interrupção (carga fria). Todos os alimentadores analisados pertencem a AES-ELETROPAULO. Os valores (em magnitude) das correntes de inrush foram analisados nos primeiros instantes (16,66 ms e 100 ms) logo após o momento da energização dos alimentadores, sendo os valores estudados como variáveis probabilísticas. As análises desta dissertação fundamentaram-se na comparação dos dados oriundos de medição com os resultados de cálculo segundo o modelo tradicional (aplicação de fatores multiplicativos), na qual se observa uma clara majoração que tende a sobredimensionar os resultados das correntes. Desta forma este trabalho sugere a adoção de valores (ou faixa de valores) mais adequados e que tendem a garantir uma aproximação mais consistente com as medições. Comparando os valores (magnitude) dos fatores multiplicativos para as correntes de inrush entre carga quente e carga fria, verifica-se que as correntes de inrush em carga fria tendem a ser maiores do que em carga quente. Bem como em ambas as cargas, observa-se a relação direta de proporcionalidade do fator multiplicativo com a potência instalada dos alimentadores em termos dos transformadores de distribuição. / The purpose of this dissertation is to analyze the inrush currents generated upon the energization of distribution system feeders. These said currents are relevant for typical designs in electric power concessionaries, for example upon calculating the ideal settings for protection devices. It was analyzed (or studies) 291 (two hundred and ninety one) oscilography samples extracted from measuring devices oscilographs were analyzed. These devices were placed in the beggining of distribution feeders, and stored information on such currents both in successful reclosing (hot load) events and re-energization after long periods of outage (cold load) events. All feeders analyzed belong to the AES-Eletropaulo. The inrush current values (in magnitude) were analyzed right after (more specifically 16.66 ms and 100 ms) the feeder energization. For this reason, its corresponding values were studied as a probabilistic variables. This analysis was based on the comparison between measured data and traditional model (application of factor coefficients) calculation results, in this way, observed it that the traditional model yields over-dimensioned results which lead to oversizement of the results currents. It has thus suggested revised, more suitable values (or bands of values) which are bound to ensure a more consistent approximation to the real measurements. Upon comparing the final value (in magnitude) results on the analysis of the factor coefficients for inrush currents for hot load and cold load, it is observed that the cold load inrush currents tend to be higher than those for hot load. Furthermore, it was observed the direct relation of proportionality of the factor coefficients to the ratings capacity transformer power installed along the feeder lines.
7

Análise das correntes transitórias de inrush em redes de distribuição. / Inrush current transients analysis in distribution feeders.

Hamilton Guilherme Bueno de Souza 01 June 2007 (has links)
O presente trabalho tem como objetivo analisar as correntes de inrush que surgem nos momentos de energização dos alimentadores de sistemas de distribuição. Desta forma, são relevantes em projetos cotidianos de concessionárias de energia elétrica como por exemplo, nos cálculos de ajustes dos dispositivos de proteção. Foram estudadas 291 (duzentas e noventa e uma) amostras extraídas de oscilografias de medidores alocados nas saídas de alimentadores de distribuição, os quais armazenaram informações de tais correntes nos momentos em que houveram religamentos bem sucedidos (carga quente), bem como em energizações após longos períodos de interrupção (carga fria). Todos os alimentadores analisados pertencem a AES-ELETROPAULO. Os valores (em magnitude) das correntes de inrush foram analisados nos primeiros instantes (16,66 ms e 100 ms) logo após o momento da energização dos alimentadores, sendo os valores estudados como variáveis probabilísticas. As análises desta dissertação fundamentaram-se na comparação dos dados oriundos de medição com os resultados de cálculo segundo o modelo tradicional (aplicação de fatores multiplicativos), na qual se observa uma clara majoração que tende a sobredimensionar os resultados das correntes. Desta forma este trabalho sugere a adoção de valores (ou faixa de valores) mais adequados e que tendem a garantir uma aproximação mais consistente com as medições. Comparando os valores (magnitude) dos fatores multiplicativos para as correntes de inrush entre carga quente e carga fria, verifica-se que as correntes de inrush em carga fria tendem a ser maiores do que em carga quente. Bem como em ambas as cargas, observa-se a relação direta de proporcionalidade do fator multiplicativo com a potência instalada dos alimentadores em termos dos transformadores de distribuição. / The purpose of this dissertation is to analyze the inrush currents generated upon the energization of distribution system feeders. These said currents are relevant for typical designs in electric power concessionaries, for example upon calculating the ideal settings for protection devices. It was analyzed (or studies) 291 (two hundred and ninety one) oscilography samples extracted from measuring devices oscilographs were analyzed. These devices were placed in the beggining of distribution feeders, and stored information on such currents both in successful reclosing (hot load) events and re-energization after long periods of outage (cold load) events. All feeders analyzed belong to the AES-Eletropaulo. The inrush current values (in magnitude) were analyzed right after (more specifically 16.66 ms and 100 ms) the feeder energization. For this reason, its corresponding values were studied as a probabilistic variables. This analysis was based on the comparison between measured data and traditional model (application of factor coefficients) calculation results, in this way, observed it that the traditional model yields over-dimensioned results which lead to oversizement of the results currents. It has thus suggested revised, more suitable values (or bands of values) which are bound to ensure a more consistent approximation to the real measurements. Upon comparing the final value (in magnitude) results on the analysis of the factor coefficients for inrush currents for hot load and cold load, it is observed that the cold load inrush currents tend to be higher than those for hot load. Furthermore, it was observed the direct relation of proportionality of the factor coefficients to the ratings capacity transformer power installed along the feeder lines.
8

The effect of supplemental food on gray squirrel movements and reproduction

Heller, David M. January 1978 (has links)
No description available.
9

[en] ANALYSIS OF CORRUGATED CIRCULAR WAVEGUIDES WHEN USED AS FEEDERS / [pt] ANÁLISE DE GUIAS CIRCULARES CORRUGADAS OPERANDO COMO ALIMENTADORES

LUIZ CLAUDIO ESTEVES 12 February 2008 (has links)
[pt] A aplicação de um guia circular corrugado como alimentador é analisada a partir do conhecimento das distribuições de campo elétrico e magnético no plano focal de refletores parabólicos. O desenvolvimento matemático dos campos no interior da estrutura conduz a expressões para os diagramas de radiação e demais parâmetros de interesse. Diversas peculiaridades inerentes à propagação em estruturas corrugadas ficam caracterizadas ao longo da análise, alcançando-se a notável situação de simetria dos diagramas e polarização cruzada nula. Inclui-se um projeto para utilização de refletores de pequena e grande distância focal. / [en] The use of a corrugated circular waveguide as a feeder is analysed by considering the distributions of eletric and magnetic fields at the focal plane of parabolic reflectors. The mathematical field development inside the structure leads to expressions of radiation patterns and the necessary parameters. Several peculiarities in connection with the propagation in corrugated structures are characterized through the analysis, obtaining the remarkable situation of patterns simmetry and zero cross- polarization. A feeder design for using small and large focal lenght reflectorsis included.
10

Trouble call analysis for single and multiple outages in radial distribution feeders

Subedi, Laxman January 1900 (has links)
Master of Science / Department of Electrical and Computer Engineering / Sanjoy Das / Anil Pahwa / Outage management describes system utilized by electric distribution utilities to help restore power in event of an outage. The complexity of outage management system employed by different utilities to determine the location of fault could differ. First step of outage management is to know where the problem is. Utilities typically depend on customers to call and inform them of the problem by entering their addresses. After sufficient calls are received, the utility is able to pinpoint the location of the outage. This part of outage management is called trouble call analysis. In event of fault in a feeder of a radial distribution system, the upstream device or the device that serves to protect that particular zone activates and opens the circuit. This particular device is considered as the operated protective device. The knowledge of the activated protective device can help locate the fault. Repair crews could be sent to that particular location to carry out power restoration efforts. The main objective of this work is to study model of distribution system that could utilize the network topology and customer calls to predict the location of the operated protective device. Such prediction would be based on the knowledge of the least amount of variables i.e. network topology and customer calls. Radial distribution systems are modeled using the immune system algorithm and test cases with trouble calls are simulated in MATLAB to test the effectiveness of the proposed technique. Also, the proposed technique is tested on an actual feeder circuit with real call scenarios to verify against the known fault locations.

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