116 documents found, page 1 of 12

The origin and architectural and technological characteristics and opportunitie...

Portugal’s EPAC (Empresa Pública do Abastecimiento dos Cereais) silo network, initially planned in the 1930s but constructed and utilised primarily in the 1970s, consisted of 31 silos with a total capacity of 841,100 t. The network’s usage declined, however, due to market liberalisation and Portugal’s accession to the European Economic Community in 1985. This study focuses on adapting a methodology to inventory...

Strategies to Reduce Mechanical Harvesting Costs in Traditional Olive Orchards

In Mediterranean basin, traditional olive orchards have an important economic value. In this type of olive orchards planting densities are 100 to 240 trees per hectare, and over 30 years old. In these olive orchards, the most used mechanical harvesting system is based on a trunk shaker to detach fruits, and an inverted umbrella to collect them. With this harvesting system it is usual to collect 70% to 90% of th...

Strategies to Reduce Mechanical Harvesting Costs in Traditional Olive Orchards

Olive harvesting mechanization is adopted in different types of olive orchards: traditional, intensive, in hedgerows. In Mediterranean basin, traditional olive orchards have an important economic value. In this type of olive orchards planting densities are 100 to 240 trees per hectare, and over 30 years old. In these olive orchards, the most used mechanical harvesting system is based on a trunk shaker to detach...

Theory of Operation of a Safety Finger Coupling Applied in the Drive of a Screw...

The aim of the study is to enhance the operational characteristics of a screw conveyor during overloading of its working mechanism by substantiating the rational parameters of the safety coupling. Theoretical calculations and their graphical dependencies were performed using the Delphi programming environment. To increase the magnitude of axial displacement of the driven half-coupling with the jammedworking ele...

Investigation of contact stresses in engagement elements of screw conveyor safe...

In the article there is presented the design of a safety clutch for a screw conveyor with time-separated modes of slipping and axial displacement of the screw for automatic restoration of the operating condition in the event of overload. A calculation has been made using contact stresses in the engagement elements of the safety device, the level of which is the determining indicator that affects the wear rate o...

Castanha - produtos diretos com fileira estabelecida

Organização do trabalho de colheita mecânica em olivais tradicionais

A mecanização da colheita de azeitona é atualmente uma prática generalizada nos vários tipos de olivais: tradicionais, intensivos e em sebe. No Nordeste de Portugal predomina o olival tradicional com densidades de plantação de 100 a 240 árvores por hectare e idade superior a 30 anos. Nestes olivais o sistema de colheita mais utilizado baseia-se num vibrador de troncos e apara-frutos. Com este sistema de colheit...

How can a changing climate influence the productivity of traditional olive orch...

Nowadays, the climate is undoubtedly one of the main threats to the sustainability of olive orchards, especially in the case of rainfed traditional production systems. Local warming, droughts, and extreme weather events are some of the climatological factors responsible for environmental thresholds in relation to crops being exceeded. The main objective of this study was to investigate the influence of microcli...

Efeito da colheita manual e mecânica de castanha (Castanea sativa Miller) ao ní...

Em 2020, em Portugal foram produzidas 42 180 toneladas de castanha, correspondendo ao sétimo e quarto lugares ao nível mundial e europeu, respetivamente. A castanha pode ser colhida manual ou mecanicamente, sendo o último processo mais eficiente. Contudo, em alguns estudos têm sido referidos a ocorrência de cortes ou abrasões na superfície dos frutos, reduzindo a sua qualidade. No presente estudo pretendeu-se e...

Melhoria dos procedimentos de colheita de castanha

No âmbito deste projeto foram realizados testes de campo com equipamentos de colheita disponíveis no mercado, que permitiram obter dados técnicos que caracterizem o funcionamento deste equipamento. Com a informação recolhida é possível responder a questões referidas pelos utilizadores, como (I) a de perda de eficiência em condições de elevada humidade e grande concentração de folhas e ouriços e (II) às questões...