Thesis (Ph. D.)--Michigan State University. Dept. of Agricultural Economics, 2006. / Title from PDF t.p. (viewed on Nov. 17, 2008) Includes bibliographical references (p. 120-124). Also issued in print.

Thesis (Ph. D.)--Harvard University, 2001. / Includes bibliographical references (leaves 547-565).

O objetivo desta tese é adaptar um modelo de integração industrial baseado no protocolo de comunicação XML Interface for Robots and Peripherals (XIRP), de modo que este pudesse ser aplicado à realidade de pequenas e médias empresas brasileiras (PMEs). Para que isto fosse possível, é necessário estudar os ambientes industriais existentes e a complexidade envolvida na tarefa de integração de dispositivos para os mesmos. Observa-se que estes ambientes são orientados a fabricante com relação às soluções criadas em termos de equipamentos e softwares. Este é o exemplo de grandes empresas como ABB, KUKA, Reis Robotics etc. O fabricante detém a solução de integração e os dispositivos, e estes só podem ser integrados em plataformas deste fabricante. O protocolo de comunicação industrial, no caso o protocolo XIRP, possibilita a comunicação entre dispositivos e sistemas controladores de maneira padronizada, permitindo que dispositivos de um fabricante se comuniquem com sistemas de outros fabricantes. Este protocolo é baseado na linguagem eXtensible Markup Language (XML) e fornece a especificação dos arquivos de esquema XML (XML schema), os quais permitem a criação de uma descrição de dispositivos e a composição de mensagens a serem trocadas entre eles. Para tanto, foi necessário criar a partir do padrão, toda a infra-estrutura de comunicação e sistema de integração de dispositivos. Vale observar que o padrão XIRP foi criado levando em consideração dispositivos microprocessados. Como este padrão ainda está em desenvolvimento, e em caso de uma eventual adaptação a ele, seria impraticável modificar inteiramente um ambiente de produção por meio de substituição de equipamentos. Desta forma, este projeto de pesquisa apresenta uma infra-estrutura que consista em um sistema integrador para a adaptação gradativa a este protocolo de comunicação. O sistema integrador proposto permite a incorporação de dispositivos XIRP ou não-XIRP. Considerando que um dispositivo já troque mensagens compatíveis com o XIRP, a sua integração e operação em um ambiente de produção seria mais simples. Todavia, mesmo neste caso, o dispositivo ainda precisaria de suporte para trabalhar em uníssono com as demais entidades pertencentes ao ambiente. Esta sinergia é incluída na especificação do ambiente integrador, porém, não faz parte dos resultados pretendidos para a presente pesquisa. Desta forma, a hipótese prevista trata os mecanismos necessários para a incorporação de dispositivos não-XIRP em um ambiente de produção compatível com o padrão XIRP, desde o processo de indexação/identificação do dispositivo à geração automática da aplicação de controle e integração em baixo nível, de modo a permitir a operação do mesmo. / The goal of this research is to adapt an industrial integration model based on the XML Interface for Robots and Peripherals (XIRP) communication protocol, such that it could be applied to the reality of Brazilian small and medium enterprises (SMEs). In order to enable this, it is necessary to study the existing industrial environments and the complexity involved in the device integration task. We observed these environments are manufacture centered considering the solutions created in terms of equipments and softwares. This is the example set by manufacturers like ABB, KUKA, Reis Robotics etc. The manufacturer detains the integration solution and the devices, and these can only be integrated in platforms of the same manufacturer. The industrial communication protocol, in this case XIRP, enables the communication among devices and controller systems in a standardized way, allowing devices from one manufacturer to communicate with systems from another. This protocol is based on the eXtensible Markup Language (XML) and supplies the specification of the XML schema files, which allows the crea- tion of a device description and the composition of messages to be exchanged among devices. Therefore a communication infrastructure and device integra- tion system was built from the standard. Note that the XIRP standard was created considering processor based devices. As this standard is still in development, and in case of an eventual adaptation to it, it would be impracticable to change an entire production environment by means of equipment exchange. Therefore, this research project presents an infrastructure that consists in an integrator system to gradually adapt to this communication protocol. The proposed integrator system allows the incorporation of XIRP or non-XIRP devices. Considering a device already exchanges messages by means of XIRP compliant messages, its integration and operation would be simpler in a production environment. However, even in this case, the device would still need support to operate in unison with other entities pertaining to the environment. This synergy is included in the specification of the integrator environment, although, it is not part of the intended results for this research. Therefore, the foreseen hypothesis deals with the necessary mechanisms to incorporate non-XIRP devices in a production environment compliant with the XIRP standard, from the device indexing/identification to the automatic generation of the control application and its low level integration, in order to allow its operation.

No description available.

No description available.

The Food Safety Modernization Act (FSMA) has a regulation stating that there can be no detectable generic Escherichia coli in agricultural water. The objective of this study was to optimize the use of peracetic acid (PAA) as a mitigating strategy in postharvest processing. This project began by investigating the impact of storage temperatures on stability of a commercially available PAA sanitizer. Regression analysis showed a quadratic relationship in the concentration of PAA over 12 weeks when storing the product at 4, 20 and 37°C. Stability of the product was also investigated in the presence of organic load over time at 60ppm PAA. PAA significantly decreased at an organic load level of 750COD. From this, the impact of various ratios of hydrogen peroxide (H2O2) and PAA were investigated further to see the efficacy against E. coli O157:H7 over three hours with reinoculation of bacteria after 3 hours. A higher level of PAA in the solution had a greater inactivation efficacy against E. coli O157:H7. The impact of concentration, organic load, temperature and pH on the efficacy against E. coli O157:H7 and stability of PAA over four hours was then investigated. All of the conditions tested showed a significant decrease in H2O2 and PAA concentrations over time, except at concentration of 80ppm, with varying rates of depletion under each condition tested. This study will help to create guidance on optimizing the use of PAA. With this knowledge growers can understand how changes in their post-harvest processing water can affect sanitizer performance.

No description available.

This study was designed to compare the price levels of the Northern and Southern marketing areas and to determine if the returns to Virginia vegetable growers would be increased if more shipments were made to the Southern area. Six crops, snap beans, cabbage, sweet corn, cucumbers, peppers, and tomatoes, were studied during 1954, 1955, and 1956. Eighteen consecutive weeks beginning near the first of June were studied during each year. Price and quantity data were collected from the daily market reports of New York, Baltimore, and Atlanta. Additional data on shipments of the six crops from Virginia were collected from Eastern Virginia vegetable producers. The prices which Virginia vegetable growers received for their produce in the terminal markets were found to be within a 25 percent range of the weekly terminal market median prices for 74 percent of the shipments where comparisons could be made. The price level in the Southern market was significantly higher than in the Northern market for snap beans, cucumbers, peppers, and tomatoes. There was no difference between the Northern and Southern market price levels for cabbage and sweet corn at the desired confidence level, but the Southern market price level was found to be higher at the 20 percent confidence level. The analysis of the two Northern markets indicates that no significant difference existed in the price levels of these markets for any of the crops. This relationship could not be accepted at the desired confidence level for cabbage, peppers, and tomatoes because the price variances were not homogeneous. After deducting transportation costs from Virginia to the respective markets, the highest net price to Virginia vegetable growers for most crops was available more often from the Southern market than in the Northern market. The study of these net prices in conjunction with the shipments by Virginia growers during the same period indicated that even though higher returns could have been realized from shipments to the Southern marketing area, Virginia growers generally did not take advantage of them. Some significant relationships between price and quantity arriving on the market were found. However, a few of the relationships did not conform to the traditional inverse relationships of the factors as expressed economic theory. Such results indicate that the data may not have been suitable for this type analysis. Complete data on the price of each unit and the total number of units in the markets should give a more reliable supply and demand relationship. Although the weekly period proved satisfactory for determining the differences in price levels of the markets, the use of such a period imposes serious limitations on the analysis of price and quantity relationships. If marketing decisions generally are made on the basis of the relative prices of the previous day or two days on the markets, the weekly period may average out many of the pertinent differences. Even though the demand in the Southern market was usually more elastic than in the Northern market, the price in the Southern market was found to generally be more responsive to a given change in quantity arriving on the market. This responsiveness of price to varying quantities arriving on the market was primarily a function of the difference in the size of the markets. The elasticity of demand of the markets was found to be of secondary importance in determining the responsiveness of price. The greatest difference in price responsiveness between the markets was for peppers. They were much more responsive to changes in the quantity arriving in the Southern market than in the Northern market. The prices of snap beans, cucumbers, and tomatoes are also more responsive to quantity changes in the Southern market. The price of sweet corn was found to be more responsive to additional carlot arrivals in the Northern market. Cabbage was not used in the calculations because the preliminary results did not conform to economic theory. / Master of Science

Thesis (MSc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / The South African agricultural sector plays an important role in creating jobs, alleviating food insecurity and poverty, and also contributes to exports. Agricultural produce from smallholder farmers is often lost after production due numerous marketing challenges which make it difficult for smallholder farmers to explore full market potentials. This, among other challenges, reduces smallholder farmers’ motivation to participate in formal (commercial) or high-value markets. The study aimed at assessing factors hindering marketing among smallholder vegetable cooperative farmers in the Polokwane Municipality. The objectives of the study were to: identify and describe socio-economic characteristics of smallholder vegetable cooperative farmers; examine the influence of socioeconomic characteristics of smallholder vegetable cooperative farmers; identify factors hindering marketing among smallholder vegetable cooperative farmers and constraints faced by smallholder vegetable cooperative farmers in the study area. Primary data with a sample size of hundred and twenty smallholder vegetable cooperative farmers was used. Descriptive statistics, the Marketing Hindrance Index and Tobit Model were employed as analytical tools to achieve the objectives of the study. Results of data analysis revealed that there are factors hindering marketing among smallholder vegetable cooperative farmers in the Polokwane Municipality. The major factors affecting smallholder farmers are source of water and types of vegetables grown, respectively. From the Tobit Model results, access to credit, access to reliable information about marketing, age, access to storage and farming experience in years were found to be significant. In view of the research findings, the recommendations of this study include: encouraging youth participation in agriculture, improved access to agricultural information and formal market access, improved access to credit and enabling accessibility through the development of better infrastructure in the form of storage facilities.

As organic fresh produce consumption has stagnated in Sweden in recent years, this study sheds light on this issue by examining factors influencing the institutional image of organic fresh produce and the confusion surrounding different kinds of eco-friendly fresh produce (eco-confusion). The influence of false facts belonging to the hedonic and utilitarian dimensions on eco-confusion and the institutional image was examined, followed by the influence of eco-confusion on the institutional image. Using the image attribution model andcentral core theory as a baseline, an expanded conceptual model was created based on anexisting qualitative study to fulfil the purpose of the research. For data collection, an online self-administered survey was distributed to consumers permanently residing in Sweden, gathering 201 valid responses. This study’s findings reveal that there is a significant influence of some of the false fact subdimensions on eco-confusion and that all four false fact subdimensions (symbolic, social, rational, sensorial) and eco-confusion significantly influencethe institutional image of organic fresh produce. The findings provide value for researchers,businesses, and society alike while also highlighting ethical considerations. Researchers can use the conceptual model developed based on the findings to further investigate eco-confusion and the image problem of organic fresh produce, organic fresh produce retailers can learn from this study and target Swedish consumers more effectively, and governments can use this paper as a reference to better educate consumers regarding eco-friendly food.