5 resultados para Quality standards

em AMS Tesi di Dottorato - Alm@DL - Università di Bologna


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Agri-food supply chains extend beyond national boundaries, partially facilitated by a policy environment that encourages more liberal international trade. Rising concentration within the downstream sector has driven a shift towards “buyer-driven” global value chains (GVCs) extending internationally with global sourcing and the emergence of multinational key economic players that compete with increase emphasis on product quality attributes. Agri-food systems are thus increasingly governed by a range of inter-related public and private standards, both of which are becoming a priori mandatory, especially in supply chains for high-value and quality-differentiated agri-food products and tend to strongly affect upstream agricultural practices, firms’ internal organization and strategic behaviour and to shape the food chain organization. Notably, increasing attention has been given to the impact of SPS measures on agri-food trade and notably on developing countries’ export performance. Food and agricultural trade is the vital link in the mutual dependency of the global trade system and developing countries. Hence, developing countries derive a substantial portion of their income from food and agricultural trade. In Morocco, fruit and vegetable (especially fresh) are the primary agricultural export. Because of the labor intensity, this sector (especially citrus and tomato) is particularly important in terms of income and employment generation, especially for the female laborers hired in the farms and packing houses. Hence, the emergence of agricultural and agrifood product safety issues and the subsequent tightening of market requirements have challenged mutual gains due to the lack of technical and financial capacities of most developing countries.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

In the last years, sustainable horticulture has been increasing; however, to be successful this practice needs an efficient soil fertility management to maintain a high productivity and fruit quality standards. For this purpose composted organic materials from agri-food industry and municipal solid waste has been used as a source to replace chemical fertilizers and increase soil organic matter. To better understand the influence of compost application on soil fertility and plant growth, we carried out a study comparing organic and mineral nitrogen (N) fertilization in micro propagated plants, potted trees and commercial peach orchard with these aims: 1. evaluation of tree development, CO2 fixation and carbon partition to the different organs of two-years-old potted peach trees. 2. Determination of soil N concentration and nitrate-N effect on plant growth and root oxidative stress of micro propagated plant after increasing rates of N applications. 3. Assessment of soil chemical and biological fertility, tree growth and yield and fruit quality in a commercial orchard. The addition of compost at high rate was effective in increasing CO2 fixation, promoting root growth, shoot and fruit biomass. Furthermore, organic fertilizers influenced C partitioning, favoring C accumulation in roots, wood and fruits. The higher CO2 fixation was the result of a larger tree leaf area, rather than an increase in leaf photosynthetic efficiency, showing a stimulation of plant growth by application of compost. High concentrations of compost increased total soil N concentration, but were not effective in increasing nitrate-N soil concentration; in contrast mineral-N applications increased linearly soil nitrate-N, even at the lowest rate tested. Soil nitrate-N concentration influenced positively plant growth at low rate (60- 80 mg kg-1), whereas at high concentrations showed negative effects. In this trial, the decrease of root growth, as a response to excessive nitrate-N soil concentration, was not anticipated by root oxidative stress. Continuous annual applications of compost for 10 years enhanced soil organic matter content and total soil N concentration. Additionally, high rate of compost application (10 t ha-1 year-1) enhanced microbial biomass. On the other hand, different fertilizers management did not modify tree yield, but influenced fruit size and precocity index. The present data support the idea that organic fertilizers can be used successfully as a substitute of mineral fertilizers in fruit tree nutrient management, since they promote an increase of soil chemical and biological fertility, prevent excessive nitrate-N soil concentration, promote plant growth and potentially C sequestration into the soil.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

I cambiamenti e le innovazioni sociali, che hanno caratterizzato il secolo scorso, hanno generato mutamenti significativi nella struttura dei consumi, legati in particolare a una maggiore consapevolezza dei consumatori e allo scoppio della crisi economica. Assume sempre maggiore importanza, all’interno delle politiche di brand management, il ruolo della Responsabilità Sociale d’Impresa, che spinge la Grande Distribuzione Organizzata a proporre prodotti con più alti standard qualitativi e di sicurezza. Il caso analizzato è quello della linea biologica ViviVerde Coop, la cui offerta di prodotti biologici a private label ha avuto un impatto molto positivo sul mercato. L’analisi dell’elasticità della curva di domanda di alcuni di questi prodotti nel periodo gennaio 2010-maggio 2012 rivela diversi valori positivi e maggiori di 1, indice del fatto che il prezzo non abbia avuto effetti negativi sulle vendite dei prodotti considerati. Tale evidenza risulta rilevante proprio in un periodo di profonda crisi economica che ha interessato, in modo significativo, anche i consumi alimentari.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Integrated production (IP) is part of the Brazilian government program to promote sustainable agricultural production. IP ensure minimum food quality standards for domestic market, and export. Furthermore, IP is considered a good option to reduce negative environmental impacts of intensive crops in tropical Savannas, including common beans, as a Brazilian staple food. Although its advantages, and the government’s effort to promote IP, few growers are adopting IP. Maybe, the perception about IP usefulness and/or its ease of use is not too clear. Moreover, the production sector is driven by market signs, and there is few information on the consumer's preferences toward IP certified products in Brazil. In this study, we sought to identify some critical factors that can influence the IP adoption in beans' production. Moreover, we sought to verify the consumers’ perceptions and intention of purchasing IP certified beans (hypothetical product). This report comprises four chapters: (1) an introduction illustrating the context in which the research was based; (2) the results on the study of IP adoption based on the Technology Acceptance Model (TAM); (3) the choice experiment results applied to identify consumers preferences and willingness-to-pay (WTP) for IP label; (4) the results on the Theory of Planned Behaviour (TPB) applied to identify consumers’ perception toward IP certified beans. This research contributes with rich information for the beans’ supply chain, providing several insights to growers, retail and other agents, including policy makers. Beans’ production sector seems to be positively intentioned to adopt IP, but further studies should be conducted to test other adoption indicators using TAM model. Surveyed consumers are willing to pay a premium price for IP labelled beans. They showed a positive attitude toward purchasing IP labelled beans. It is an important information to motivate production sector to offer certified beans to the market.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The research activity carried out during the PhD course in Electrical Engineering belongs to the branch of electric and electronic measurements. The main subject of the present thesis is a distributed measurement system to be installed in Medium Voltage power networks, as well as the method developed to analyze data acquired by the measurement system itself and to monitor power quality. In chapter 2 the increasing interest towards power quality in electrical systems is illustrated, by reporting the international research activity inherent to the problem and the relevant standards and guidelines emitted. The aspect of the quality of voltage provided by utilities and influenced by customers in the various points of a network came out only in recent years, in particular as a consequence of the energy market liberalization. Usually, the concept of quality of the delivered energy has been associated mostly to its continuity. Hence the reliability was the main characteristic to be ensured for power systems. Nowadays, the number and duration of interruptions are the “quality indicators” commonly perceived by most customers; for this reason, a short section is dedicated also to network reliability and its regulation. In this contest it should be noted that although the measurement system developed during the research activity belongs to the field of power quality evaluation systems, the information registered in real time by its remote stations can be used to improve the system reliability too. Given the vast scenario of power quality degrading phenomena that usually can occur in distribution networks, the study has been focused on electromagnetic transients affecting line voltages. The outcome of such a study has been the design and realization of a distributed measurement system which continuously monitor the phase signals in different points of a network, detect the occurrence of transients superposed to the fundamental steady state component and register the time of occurrence of such events. The data set is finally used to locate the source of the transient disturbance propagating along the network lines. Most of the oscillatory transients affecting line voltages are due to faults occurring in any point of the distribution system and have to be seen before protection equipment intervention. An important conclusion is that the method can improve the monitored network reliability, since the knowledge of the location of a fault allows the energy manager to reduce as much as possible both the area of the network to be disconnected for protection purposes and the time spent by technical staff to recover the abnormal condition and/or the damage. The part of the thesis presenting the results of such a study and activity is structured as follows: chapter 3 deals with the propagation of electromagnetic transients in power systems by defining characteristics and causes of the phenomena and briefly reporting the theory and approaches used to study transients propagation. Then the state of the art concerning methods to detect and locate faults in distribution networks is presented. Finally the attention is paid on the particular technique adopted for the same purpose during the thesis, and the methods developed on the basis of such approach. Chapter 4 reports the configuration of the distribution networks on which the fault location method has been applied by means of simulations as well as the results obtained case by case. In this way the performance featured by the location procedure firstly in ideal then in realistic operating conditions are tested. In chapter 5 the measurement system designed to implement the transients detection and fault location method is presented. The hardware belonging to the measurement chain of every acquisition channel in remote stations is described. Then, the global measurement system is characterized by considering the non ideal aspects of each device that can concur to the final combined uncertainty on the estimated position of the fault in the network under test. Finally, such parameter is computed according to the Guide to the Expression of Uncertainty in Measurements, by means of a numeric procedure. In the last chapter a device is described that has been designed and realized during the PhD activity aiming at substituting the commercial capacitive voltage divider belonging to the conditioning block of the measurement chain. Such a study has been carried out aiming at providing an alternative to the used transducer that could feature equivalent performance and lower cost. In this way, the economical impact of the investment associated to the whole measurement system would be significantly reduced, making the method application much more feasible.