1,721,030 research outputs found
Investigating Research Trends in Computer Vision for Food Quality Control: A Bibliometric Approach
No full textA new approach for the optimization of UV-reactor design by mean of CFD simulation
No full textUltraviolet (UV) sterilization is an emerging technology for beverages and waste water treatment. It can either be used as disinfection barrier, where the UV light is used to inactivate pathogenic microorganisms, or in combination with hydrogen peroxide as an advanced oxidation process. In this paper, a new simulative approach is presented for both fluid dynamics and optical optimization of UV reactors. The fluid dynamics analysis is carried out with a commercial CFD software (Tdyn Multyphisics), while the optical simulation is done by mean of an original tool, named "UVdose", which was developed in collaboration with the software developer SmartCAE. This software takes into account both physical-chemical parameters of water (i.e., turbidity) and optical effects, such as refraction; as output, it provides the statistical distribution of the dose absorbed by the fluid across the reactor. We consider two configurations of the reactor. The first one is a commercial UV reactor with 3 medium-pressure lamps, designed by the Italian company Puro s.r.l.; the second one is a modified configuration of the same reactor, with a different placement of the lamps. These configurations are compared from both the fluid dynamics and optical point of view, in order to identify the configuration which provides the best treatment to the fluid processed. For this latter configuration, we finally develop a framework which correlates the minimum UV dose required with some design parameters of the reactor, and is thus useful during the design stage of UV reactors. The method we used in this paper can be extended to the optimization of any type of UV reactors, including more operating parameters of the reactor (e.g., type and number of lamps, type and number of baffles, layout etc...
A New Method for the Validation of Ultraviolet Reactors by Means of Photochromic Materials
No full textThe interest in ultraviolet (UV) water sterilization has grown significantly in recent years. The main difficulty in designing a UV reactor is to assess the UV dose delivered. In fact, that dose depends on both the UV radiation field and the flow distribution within the reactor. At the design phase, computational fluid dynamics (CFD) helps to predict the UV dose distribution, but it requires a validation; nowadays, such validation is possible only using the Lagrangian actinometry method. This promising technique, however, requires a complex and expensive equipment, which makes it difficult to apply in most of the real contexts. The purpose of this work is to develop a new method to make the validation of the UV reactor performance a faster, less expensive, and more sustainable procedure. To this aim, we used two photochromic materials, sensitive to the UV-C radiation. Each material has been characterized by relating its color variation with the absorbed UV dose. Samples of such materials, in some cases stuck on supports characterized by different densities, were then inserted within a pilot UV reactor under three different flow rates, to measure the dose distributions. These latter were then compared with the results obtained by the CFD simulations performed on the same reactor geometry, and by biodosimetry analyses. The best results, both in terms of average value and distributions of the UV dose, were obtained from the photochromic amorphous polypropylene samples, having a density similar to that of water. This method emerges then as a promising validation technique, able also to assess the dose distribution of a UV reactor
Abatement of volatile organic compounds in industrial bakery plants: state-of-the-art and technical-economic evaluation for a plant in northern Italy
No full textPerformance analysis of the water supply system of a dairy company by means of an advanced simulation tool
No full textThis work presents the result of a research project, concerning the development of a simulation model for a water supply system of a dairy company, located in Parma, Italy. The approach developed allows investigating, through process simulation, the plant areas where the efficiency of the water supply system can be significantly improved by means of some simple interventions. The final objective is to reduce the water consumption of the plant; this represents a relevant issue to the dairy industry. In line with this goal, at first the simulation model was used to reproduce the current (AS IS) system, so as to reach a precise knowledge of the water flows in the plant. In the second part of the work, a series of alternative (TO BE) scenarios was investigated, and the related performance was assessed, thus identifying the best plant configuration. The process simulator was designed under Microsoft Excel, programmed with Visual Basic for Applications. Thanks to the study implemented, an optimal scenario of the water supply system was finally identified, which allows savings up to 7.2% of water compared to the original configuration
Single sourcing vs. double sourcing: a simulation approach for supplier selection
No full textThe paper presents a simulation approach to the supplier selection problem. Specifically, the aim of the model is to compare a scenario where a company exploits only one supplier (single sourcing) with a double sourcing option. In the case of double sourcing, the second supplier has a higher reliability compared to the first one, meaning that it is always able to deliver the product required within a defined lead time; however, products are supplied at a higher price, thus generating higher costs for the company. Under both scenarios, it is hypothesized that the company adopts an Economic Order Interval (EOI) reorder policy. Overall, the study
is articulated into two steps and has the final aim to compare the single sourcing and double sourcing strategies, to assess the economic profitability of those solutions depending on the operating conditions of the
company. Related results will provide companies with some economic benchmark for pondering purchasing options
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