1,721,008 research outputs found
Simulation based performance evaluation of co-current and counter-current flows secondary packaging plants for food products
No full textREF06
Modelling techniques for the control of thermal exchanges in mixed continuous-discontinuous flow food plants
No full textPlant layout and pick-and-place strategies for improving performances in secondary packaging plants of food products
Full text linkThe aim of secondary packaging plants is to pick food products from a conveyor belt and to place them into boxes. The typical configuration of these packaging plants consists of a set of sequential robot stations, performing pick and place cycles from one conveyor to another parallel one, which transport the products and the boxes to be filled. Depending on the relative movement of the two conveyors, the plant operates in co-current or counter-current flow configuration. Undesired perturbations in the product flow rate from its nominal value can lead to critical events, i.e. unpicked product at the end of the first conveyor or not-completely filled boxes. Even if the structures of co-current flow and of counter-current flow plants, are very similar, their behaviour in non-nominal or perturbed conditions can be significantly different.
The aim of this paper is to deeply investigate the behaviour of these two kinds of secondary packaging lines, evaluating their performances in the case of different pick and place strategies, using discrete events simulation techniques.
Results show to which extent the different proposed control strategies can improve the performances of both co-current and counter-currents plants and, in particular, how co-current plant layouts can achieve performances which are equivalent to, or perhaps even better than, those that can be obtained with a counter-current plant layout, that cannot be freely used since it has been patented. The simulation tool, control algorithms and results presented can help packaging plant designers for choosing the most appropriate solutions and for properly sizing the plant. Copyright © 2012 John Wiley & Sons, Ltd
Innovazione nelle linee di per il packaging secondario.
No full textL’utilizzo dell’aria compressa nelle linee di packaging per i prodotti alimentari consente di ottenere macchinari con elevate prestazioni e basso tasso di danneggiamento dei prodotti manipolati. In questo articolo, focalizzato sulle linee
per il packaging secondario, sono presentati i principali dispositivi pneumatici usati in questi tipi di macchine e le moderne tecniche di progettazione assistita per l’ottimizzazione delle prestazioni degli impianti
Correlation between power harrow energy demand and tilled soil aggregate dimensions
Full text linkEnergy demand of soil tillage implements has been reported based on different operating conditions and the chemical and physical soil properties. However, tillage operations cannot only be evaluated according to their energy consumption; the soil structure improvement and the consequent agronomic benefits must also be considered. Power harrows can adjust soil clod size by varying the velocity ratio (λ) of the machinery which is calculated from the ratio of the peripheral speed of the tine rotors and the vehicle's advancing speed. This paper aims to gain deeper insight into controlling the soil structure and find correlations with the power harrow's energy requirement in different setups. Field tests were conducted at the experimental farm of the University of Bologna on a 3-m working width power harrow coupled with a tractor with 107 kW of rated engine power. Field tests were performed by varying λ from 1.46 to 7.90 while tractor parameters, such as speed, engine power, fuel rate consumption, draught, and power take-off (PTO) speed and torque, were acquired with a datalogger. After harrowing, soil samples were sieved and significant granulometric parameters were calculated and correlated to data acquired from the tractor–power harrow system. The results show that the optimum conditions for a high-quality seedbed are obtained with high values of implement–soil impact speed, whilst λ should be kept as low as possible to minimise the fuel consumption per ha
Modeling techniques for the control of thermal exchanges in mixed continuous-discontinuous flow food plants.
No full textCooperative Agricultural Operations of Aerial and Ground Unmanned Vehicles
Full text linkPrecision agriculture comprises a set of technologies that combines sensors, information systems, enhanced machinery, and informed management to optimize production by accounting for variability and uncertainties within agricultural systems. Autonomous ground and aerial vehicle can lead to favorable improvements in management by performing in-field tasks in a time-effective way. Greater benefits can be achieved by allowing cooperation and collaborative action among Unmanned Aerial Vehicles (UAVs) and Unmanned Ground Vehicles (UGVs). A multi-phase approach is here proposed, where each unmanned vehicle involved has been conceived and will be designed to implement innovative solutions for automated navigation and infield operations within a complex irregular and unstructured scenario as vineyards in sloped terrains
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cooperation of unmanned systems for agricultural applications: A theoretical framework
Full text linkAgriculture 4.0 comprises a set of technologies that combines sensors, information systems, enhanced machinery, and informed management with the objective of optimising production by accounting for variabilities and uncertainties within agricultural systems. Autonomous ground and aerial vehicles can lead to favourable improvements in management by performing in-field tasks in a time-effective way. In particular, greater benefits can be achieved by allowing cooperation and collaborative action among unmanned vehicles, both aerial and ground, to perform in-field operations in precise and time-effective ways. In this work, the preliminary and crucial step of analysing and understanding the technical and methodological challenges concerning the main problems involved is performed. An overview of the agricultural scenarios that can benefit from using collaborative machines and the corresponding cooperative schemes typically adopted in this framework are presented. A collection of kinematic and dynamic models for different categories of autonomous aerial and ground vehicles is provided, which represents a crucial step in understanding the vehicles behaviour when full autonomy is desired. Last, a collection of the state-of-the-art technologies for the autonomous guidance of drones is provided, summarising their peculiar characteristics, and highlighting their advantages and shortcomings with a specific focus on the Agriculture 4.0 framework. A companion paper reports the application of some of these techniques in a complete case study in sloped vineyards, applying the proposed multi-phase collaborative scheme introduced here
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