Este trabalho apresenta a análise teórica e experimental do gerador assíncrono de dupla alimentação, denominado GEADA ao longo deste trabalho, operando em regime permanente com velocidade não fixa, mas com freqüência da armadura constante. Compreende o escopo do trabalho a análise teórica a partir do circuito equivalente do gerador, a análise teórica e experimental da curva de magnetização do GEADA operando em freqüência do rotor variável, uma proposta de adaptação da curva de capacidade aplicada na operação dos geradores síncronos para o GEADA e a sua análise considerando-o como máquina síncrona a partir dos seus terminais, os ensaios normalizados e complementares necessários para o levantamento dos parâmetros para este circuito equivalente e ensaios do GEADA operando com carga para verificação de seu desempenho Os resultados obtidos permitem um melhor entendimento desse sistema de geração, de suas condições de operação e utilização em sistemas de geração de velocidade não fixa como, por exemplo, sistemas eólicos e hidrelétricos. / The study presents the theoretical and experimental analysis of the double fed asynchronous generator, called GEADA, operating in steady state with non-fixed speed but with constant armature frequency. It comprehends the theoretical analysis based on the equivalent circuit of this generator, the theoretical and experimental analysis of the curve of magnetization of the GEADA operating with variable rotor frequency. A proposal of adaptation of the capability curve applied in the operation of the synchronous generators for the GEADA is also presented, its analysis considering it as a synchronous machine from its terminals, the standard and complementary tests necessary for the calculation of the parameters for the equivalent circuit and the tests with the GEADA operating under on-load conditions to verify its performance. The achieved results allow a better understanding of this generation system, its operational conditions and applicability to the power generation systems based on variable speed, such as wind and hydroelectric power plants.

Este trabalho apresenta a análise teórica e experimental do gerador assíncrono de dupla alimentação, denominado GEADA ao longo deste trabalho, operando em regime permanente com velocidade não fixa, mas com freqüência da armadura constante. Compreende o escopo do trabalho a análise teórica a partir do circuito equivalente do gerador, a análise teórica e experimental da curva de magnetização do GEADA operando em freqüência do rotor variável, uma proposta de adaptação da curva de capacidade aplicada na operação dos geradores síncronos para o GEADA e a sua análise considerando-o como máquina síncrona a partir dos seus terminais, os ensaios normalizados e complementares necessários para o levantamento dos parâmetros para este circuito equivalente e ensaios do GEADA operando com carga para verificação de seu desempenho Os resultados obtidos permitem um melhor entendimento desse sistema de geração, de suas condições de operação e utilização em sistemas de geração de velocidade não fixa como, por exemplo, sistemas eólicos e hidrelétricos. / The study presents the theoretical and experimental analysis of the double fed asynchronous generator, called GEADA, operating in steady state with non-fixed speed but with constant armature frequency. It comprehends the theoretical analysis based on the equivalent circuit of this generator, the theoretical and experimental analysis of the curve of magnetization of the GEADA operating with variable rotor frequency. A proposal of adaptation of the capability curve applied in the operation of the synchronous generators for the GEADA is also presented, its analysis considering it as a synchronous machine from its terminals, the standard and complementary tests necessary for the calculation of the parameters for the equivalent circuit and the tests with the GEADA operating under on-load conditions to verify its performance. The achieved results allow a better understanding of this generation system, its operational conditions and applicability to the power generation systems based on variable speed, such as wind and hydroelectric power plants.

Este trabalho apresenta a análise teórica e experimental do gerador assíncrono de dupla alimentação, denominado GEADA ao longo deste trabalho, operando em regime permanente com velocidade não fixa, mas com freqüência da armadura constante. Compreende o escopo do trabalho a análise teórica a partir do circuito equivalente do gerador, a análise teórica e experimental da curva de magnetização do GEADA operando em freqüência do rotor variável, uma proposta de adaptação da curva de capacidade aplicada na operação dos geradores síncronos para o GEADA e a sua análise considerando-o como máquina síncrona a partir dos seus terminais, os ensaios normalizados e complementares necessários para o levantamento dos parâmetros para este circuito equivalente e ensaios do GEADA operando com carga para verificação de seu desempenho Os resultados obtidos permitem um melhor entendimento desse sistema de geração, de suas condições de operação e utilização em sistemas de geração de velocidade não fixa como, por exemplo, sistemas eólicos e hidrelétricos. / The study presents the theoretical and experimental analysis of the double fed asynchronous generator, called GEADA, operating in steady state with non-fixed speed but with constant armature frequency. It comprehends the theoretical analysis based on the equivalent circuit of this generator, the theoretical and experimental analysis of the curve of magnetization of the GEADA operating with variable rotor frequency. A proposal of adaptation of the capability curve applied in the operation of the synchronous generators for the GEADA is also presented, its analysis considering it as a synchronous machine from its terminals, the standard and complementary tests necessary for the calculation of the parameters for the equivalent circuit and the tests with the GEADA operating under on-load conditions to verify its performance. The achieved results allow a better understanding of this generation system, its operational conditions and applicability to the power generation systems based on variable speed, such as wind and hydroelectric power plants.

Master of Agribusiness / Department of Agricultural Economics / Michael R. Langemeier / The cattle market has drastically changed over the last half century. Today, ranchers and farmers are faced with various governmental regulations as well as fluctuating grain and fuel prices. While beef may still be a commodity, it can be sold in specialized markets, in markets that have enhanced consumer demand. It is nearly impossible for a producer with a small herd to compete with a larger ranch if they are selling their cattle as a commodity. The primary economic objective of the producer is to generate revenue. Producers must be profitable to remain in business as well as provide a livelihood for their family. Providing a quality product is part of the business model. Choice within a marketplace is beneficial for producers and consumers. That said forage-fed beef will prosper in marketplaces where consumers desire their product more than alternate products. If producers are intent on progressively growing their market share, Georgia-grown, forage-fed beef must be marketed correctly. This includes promoting it on a basis of locally grown, pasture raised, and other attributes consumer’s desire. The results of the marketing survey present data that may be helpful when marketing Georgia-grown, forage-fed beef. The weekly consumption of beef products provided insight into the potential scope of the market. Approximately 39 percent of respondents consumed beef products three or more times per week. Additionally, 43 percent of the respondents were not familiar with forage-fed beef. This is a significant share of the market that is possibly open to a new product like Georgia-grown, forage-fed beef. Similarly, traceability of the product was an important feature that customers preferred. In addition to a larger selection of naturally produced beef products, respondents also indicated they were willing to pay more for the product. Approximately 49 percent of the respondents indicated that they would be willing to pay up to a dollar more per pound for Georgia-grown, forage-fed beef. Another 30 percent of the respondents indicated that they would be willing to pay more than $1 per pound for Georgia-grown, forage-fed beef. The results of the survey appear to offer opportunities for producers of Georgia-grown, forage-fed beef to expand their market share.

Master of Science / Department of Agricultural Economics / Ted C. Schroeder / Newer marketing techniques and production technologies have made large amounts of data available in fed cattle production that previously were not available to the cow-calf producer. The application of this data in breeding and management practices has only begun to be evaluated. This research used individual records, taken from birth to slaughter, on 6,360 calves from a single cow-calf producer who retained ownership of the calves through a custom feed yard and marketed them in a grid system. Using this information, four major topics were analyzed; identifying profitability drivers among animal characteristics, assessing weaning weight as a predictor of finished performance, utilizing lifetime performance of calves to evaluate cow productivity, and quantifying the effects of illness on cattle efficiency and carcass quality. The main profitability driver was hot carcass weight, while avoiding quality and yield grade discounts was also imperative to returns. Weaning weight did not prove to be a highly accurate tool to predict the finished quality and profitability of an animal. Evaluations of cow performance based on calf productivity were accomplished, accounting for all variation possible, however since sires were not known these performance evaluations may not be capturing an accurate picture of maternal influence on calf genetics. Performance evaluations can still be useful, but it is suggested that they not be the basis for all culling and replacement decisions. Evaluating calves based on the age of their dam highlights a peak in performance in most all measures when a cow is 7 years old. Illness in the feedlot linearly affected Net Return in a negative fashion and also negatively influenced Return to Ranch. This was mostly related to losses in efficiency, but also losses in hot carcass weight and dressing percentage in highly treated animals.

ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Aerocross Systems, Inc. is developing a low-cost unmanned airborne telemetry relay system to augment the USAF Air Armament Center’s Eglin Gulf Range instrumentation resources. The system is designed to remotely autotrack and relay S-Band telemetry and VHF/UHF voice communications from test articles beyond the line-of-sight of land-based instrumentation. The system consists of a medium altitude/endurance Unmanned Aerial Vehicle (UAV), a Mission Control Station, and a remotely operated telemetry/voice tracking and relay instrumentation suite. Successfully developed and deployed, the system will contribute to lower range costs while enhancing range instrumentation performance.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: A survey to assess the sustainability and marketing opportunities for smallholder cattle production systems was conducted by consulting with a total of 95 smallholder cattle producers in Ncorha and Gxwalibomvu communities in the Eastern Cape Province (ECP) of South Africa. In addition, a total of 18 surrounding beef retailers, 5 abattoirs that supplied beef to these retailers and 155 beef consumers who bought beef from these retailers between February 2013 and February 2014 were also interviewed using pretested structured questionnaires. The surveys established the perception of beef traders and consumers on the development of a Natural beef (NB) brand and indicated the willingness of participants to support the development of a NB brand. The results indicated that a smallholder beef cattle production system was socially and environmentally conditionally sustainable but economically not sustainable. Overall, the system was conditionally sustainable. Cattle herd size was bigger in Ncorha than in Gxwalibomvu (13.7±1.9 vs. 11.3 ± 1.9 heads of cattle, respectively). Smallholder producers from both sites sold an average of two cattle per year. Young farmers (<40 years old), Christians and small households (<5 members) had a greater potential to sell cattle than adults (>40 years old), traditionalists and larger households (>5 members). Similarly, households with access to extension services, owners of smaller cattle herds (<10 cattle) and from a lower income bracket (<R3000) had a bigger potential to sell cattle. More than 70% of consumers were willing to buy a NB brand once it is available on the market but were not willing to pay a premium for the beef brand. Consumers’ willingness to buy and pay a premium for a NB product was influenced by gender, age, income source, with meat preference and meat consumption frequency playing the biggest role in decision making. On the other hand, retailers were not willing to participate in the development of a NB brand. Beef traders, however, suggested that communal feedlotting, group marketing and characterization of beef from cattle fed natural pasture-based diets to identify unique quality attributes of such beef, can potentially improve offtake and economic sustainability of smallholder cattle production systems. The study concluded that smallholder cattle production systems in the ECP is conditionally sustainable, and opportunities for the integration of smallholder cattle producers into the formal beef market value chain lies in the characterization of natural pasture-fed beef, feedlotting and group marketing. / AFRIKAANSE OPSOMMING:'n Opname om die volhoubaarheid en bemarkingsgeleenthede vir kleinboer vleisbeesproduksiestelsels te evalueer, is deur middel van konsultasie met 'n totaal van 95 kleinboere vee produsente in Ncorha en Gxwalibomvu gemeenskappe in die Oos-Kaap Provinsie van Suid-Afrika, uitgevoer. Daarbenewens is altesame 18 omliggende vleis kleinhandelaars, 5 abattoirs wat beesvleis verskaf aan hierdie kleinhandelaars en 155 beesvleis verbruikers wat vleis gekoop het van die kleinhandelaars tussen Februarie 2013 en Februarie 2014, met behulp van vooraf-getoetste gestruktureerde vraelyste ondervra. Die opnames het die mening van beesvleis handelaars en -verbruikers oor die ontwikkeling van 'n natuurlike weiding-geproduseerde beesvleis (NPB) handelsmerk ingewin en ook die bereidwilligheid van die deelnemers om die ontwikkeling van 'n NPB handelsmerk te ondersteun, aangedui. Die bevindinge dui daarop dat 'n kleinskaalse vleisbees produksiestelsel sosiaal en omgewingsvriendelik voorwaardelik volhoubaar is, maar nie ekonomies volhoubaar is nie. In geheel is hierdie tipe produksiestelsel as voorwaardelik volhoubaar beskou. Beestrop grootte was groter in die Ncorha as in die Gxwalibomvu gemeenskappe (13.7 ± 1.9 beeste vs. 11.3 ± 1.9 beeste, onderskeidelik). Kleinboer produsente van beide areas het 'n gemiddeld van twee beeste per jaar verkoop. Jong boere (<40 jaar oud), Christene en klein huishoudings (<5 lede) het 'n beter potensiaal gehad om beeste te verkoop as volwassenes (> 40 jaar oud), tradisionele boere en groter huishoudings (> 5 lede). Net so het huishoudings met toegang tot voorligtingsdienste, eienaars van klein troppe (<10 beeste) en boere wat aan die laer inkomstegroep behoort het (<R3000), ʼn groter potensiaal gehad om vee te verkoop. Meer as 70% van verbruikers was bereid om vir 'n NPB produk te betaal sodra dit beskikbaar is op die mark, maar was nie bereid om 'n premie vir die NPB handelsmerk te betaal nie. Verbruikers se bereidwilligheid om NPB produkte te koop en ʼn premie te betaal vir die handelsmerk was deels beïnvloed deur geslag, ouderdom, bron van inkomste en die meeste deur vleis voorkeur en frekwensie van vleis verbruik. Kleinhandelaars was nie bereid om deel te neem aan die ontwikkeling van ʼn NPB handelsmerk nie. Bees handelaars het egter voorgestel dat kommunale voerkrale, groepsbemarking en karakterisering van vleis van beeste gevoer op natuurlike weiding om die unieke kwaliteitseienskappe van die tipe vleis vas te stel, potensieel afsette en ekonomiese volhoubaarheid van kleinboere produksie beeste stelsels kan verbeter. Die studie het bevind dat kleinboer veeproduksiestelsels in die Oos-Kaap Provinsie voorwaardelik volhoubaar is en dat geleenthede vir die integrasie van kleinboer beesprodusente in die formele vleisbeesmark waardeketting in die karakterisering van beesvleis geproduseer op natuurlike weiding, voerkrale en groepsbemarking, vervat is.

<p>The goal of this work was to contribute to the fed-batch process optimisation task by deriving parameters that have considerable impact on productivity as well as product quality The chosen parameters were I) the design of the glucose feed profile, II) the choice of induction strategy, with respect to the method of addition, and III) the time of the induction, with respect to the specific glucose consumption rate. </p><p>The present fed-batch experiments using the lacUV5-promoter, for production of b-galactosidase, have shown that a high glucose feed rate gives a specific production rate, q_p, that is twice as high, after induction, compared to a feed rate that is 2.5 times lower. The constant accumulation of lacZ-mRNA indicates that the translational capacity is initially limiting the synthesis machinery, but after four hours of maximum specific production and a corresponding drop in lacZ-mRNA production, the cultivation is likely to be transcription limited. The high feed-rate system resulted in high accumulation of β-galactosidase, corresponding to 40% of total cellular proteins.</p><p>By design of feed profiles in a fed-batch process the detrimental effects of overflow metabolism, giving acetic acid formation, can be avoided. However, the results show that a one-dose addition of isopropyl-β-D-galactopyranoside (IPTG), provokes a non-growth associated production of acetic acid. This response can be alleviated by; lowering the inducer concentration (in this case to below 165 μM), by further reducing the feed rate of glucose or by using alternative induction methods. The use of a stepwise addition or a feed of IPTG thus delayed and reduced the level of acetic acid accumulation. It was also shown that a small change in the time-point of induction lead to large variability, regarding both productivity and acetic acid accumulation, in a fed-batch cultivation, </p><p>In order to further investigate the protein quality two additional proteins were studied in fed-batch cultivations using high and low glucose feed. The aim was to prove the hypothesis that the feed related change in the rate of synthesis of the nascent polypeptide controls the product quality. For the two proteins: Zb-MalE (wt) and Zb-MalE31 (mutant), the transcription rate, in terms of amount of IPTG, and translation rate, in terms of changes in feed rate, influences the percentage of inclusion body formation and degradation of nascent polypeptide. The data show a higher rate of inclusion body formation for the model protein Zb-MalE31 during high feed rate cultivations, as well as at high levels of inducer. Furthermore, the rate of proteolysis was significantly higher for a high feed rate. The high feed rate thus results in a higher rate of synthesis but a lower corresponding quality, for the model proteins studied.</p><p>In the present investigation of fed-batch cultivations using several different expression vectors, it was found that the central alarmone guanosine tetraphosphate (ppGpp) was formed at both high and low feed rates upon induction. It could be shown, however, that by secretion of Zb-MalE to the periplasm, the stringent response could be avoided. This might be due to the decreased burden on the host where the secretion of product further seems to make the cell able to redirect the carbon flux from overflow metabolism, since no acetic acid was produced. The secretion also demonstrates that the growth arrest could be aborted, which is otherwise gained in the P_malKproduction system.</p><p>A novel fed-batch process based on the promoters for the universal stress proteins A and B (P_uspA, P_uspB) was designed to make use of these powerful promoters in an industrial production context. It was concluded that the process had to start from a high specific growth rate and induction was performed once a limiting feed started. This was done to purposely induce the stringent response and/or acetic acid accumulation since this was required for induction. In the suggested system, induction has to be performed and maintained at continuous substrate feeding, whilst avoiding exceeding the cellular capacity, since the stationary phase starvation alone did not lead to production. In conclusion, a new stress induction based production system was achieved resulting in high accumulations of product protein without any detected metabolic side effects.</p>

Flow variability plays an important role in structuring lotic communities, yet comparatively little is known about processes governing assemblage dynamics in stream ecosystems with stable environmental conditions, such as spring-fed rivers. Volcanic spring-fed rivers (hereafter spring-fed rivers) occur in geologically active landscapes of the western USA and around the globe. We sampled invertebrate assemblages and quantified primary productivity and habitat characteristics of spring-fed and runoff rivers in northern California over 4 seasons. We predicted that abiotic factors would be more stable and nutrient availability greater and that invertebrate density would be greater and diversity lower in spring-fed than in runoff rivers. Runoff rivers exhibited high variability in discharge and temperature, whereas spring-fed rivers were relatively stable with high naturally occurring nutrient levels. On average, NO3- and PO43- concentrations were 40x greater in spring-fed than in runoff rivers. Spring-fed rivers supported nearly 7 to 16x greater densities of invertebrates than runoff systems, depending on season. However, invertebrate species richness was greater in runoff rivers in all seasons. Spring-fed river invertebrate assemblages were strongly correlated with elevated nutrient concentrations and basal C sources, whereas runoff assemblages were associated with discharge variability and median substrate size. We suggest that strong differences in abiotic variability between spring-fed and runoff rivers play an important role in determining invertebrate assemblage structure. Because spring-fed rivers exhibit more stable temperatures throughout the year and lower temperatures during the summer than runoff rivers, they may provide essential refugia for coldwater taxa in a warming climate.

This thesis analyzes the causes and impacts of recent financial crisis, which originated in the U. S. in 2007. It deals with the theoretical view and the specification of the financial crisis. A significant part is devoted to analyzing the root causes of the emergence of the recent financial crises. Here we find important implications in the functioning and structure of the financial system, in which we see many long-term unhealthy factors which largely contributed to the crisis. The paper also deals with analysis of the financial crisis on the real economy. It analyzes the impact of the crisis on the main macroeconomic indicators in the U. S. and Europe. Here we find an analysis of the measures taken in the U. S. and the EU in order to stabilize the financial sector. Find negative effects of state aid to public debt and government budget deficits.