1,720,963 research outputs found
Analysis and Design of Direct Steam Injection for Tomato Concentrate Sterilization
No full textDirect Steam Injection (DSI) is a sterilization technique which is often used for high viscosity fluid food when the preservation of the quality characteristics and energy efficiency are the priority.
In this work an apparatus for the sterilization of tomato concentrate has been analyzed by means of a 3D Computational Fluid Dynamics (CFD) model, in order to optimize the exchanger performance in term of temperature distribution inside the product.
A multidimensional two-phase model of steam injection inside a non-Newtonian pseudoplastic fluid was adopted to evaluate the thermal history of the product and the condensation rate of the steam injected in the heat exchanger during the thermal process.
Subsequently the CFD analysis has been extended to examine the effects of the different process parameters (sterilization temperature, steam flow rate, radial and axial temperature profiles, and nozzle geometry) on the resulting product.
Result obtained allowed to understand the effects of process parameters on the behavior of the condensing steam and obtain better performance of the exchanger in terms of temperature distribution of the threated product
Modeling and Simulation of an Aseptic Flash Cooler for Tomato Concentrate Sterilization
No full textDirect steam injection (DSI) is a sterilization technique which is often used for high viscosity fluid food when the preservation of the quality characteristics and energy efficiency are the priority.
In this work an apparatus for the sterilization of tomato concentrate has been analyzed by means of multidimensional CFD (Computational Fluid Dynamics) models, in order to optimize the quality and safety of the treated food.
A multidimensional two-phase model of steam injection inside a non-newtonian pseudoplastic fluid was adopted to evaluate the thermal history of the product and the steam consumption during the target process.
Subsequently CFD analysis has been extended to examine the effects of the different process parameters (sterilization temperature, steam flow rate, radial and axial temperature profiles, nozzle geometry) on the resulting product.
Result obtained are in agreement with available data acquired in industrial plant
Computational fluid dynamics (CFD) modelling and experimental validation of thermal processing of canned fruit salad in glass jar
Full text linkIn this paper the heat transfer of a fruit salad during the pasteurization treatment was investigated. The objective of the paper was to develop and validate a computational fluid dynamics (CFD) model for predicting the temperature profiles during the thermal processing of this sample. Samples of a commercial fruit salad, composed of five different fruits with different shapes, sizes and thermal properties, submerged in water/sugar syrup, were submitted to thermal treatments in a pilot plant and temperature profiles at different locations were experimentally recorded. Results showed that the slowest heating point (SHP) was positioned at 19–20% of the can height: fruit closest to the SHP such as pear presented the lowest F value. Moreover, F values resulted to be influenced by the distance from the jar bottom as
function of natural convection motion of the syrup. CFD model simulations data were then successfully validated against the experimental ones: results, expressed as RMSE, showed a good fitting between calculated and experimental data, both for syrup (mean RMSE 1.47 C) and fruit pieces (mean RMSE 1.63 C). In addition, F values calculated from both experimental and simulated temperatures resulted very similar with only little differences. In conclusion, the proposed approach and mathematical model can thus be usefully applied for the simulation and prediction of thermal processes of canned fruit salad for process design and optimization
MODELLING AND SIMULATION OF THE STERILIZATION PROCESS OF POUCH PACKAGING IN AN ASEPTIC LINE
No full textComputational Fluid Dynamic (CFD) models were used in this paper to analyze and improve the sterilization process of spouted pouch with a mixture of air and Vaporized Hydrogen Peroxide (VHP) for an aseptic line. In the first part of the work the process of sterilization of spouted pouches has been analyzed using a mixture composed by vaporized hydrogen peroxide and hot sterile air. Simulations allowed reaching the best combination between nozzle position and geometrical shape of output section. In the second part of the work was carried out the simulation of the flow of sterile air in order to obtain the value of flow rate which could ensure the complete removal of the sterilizer with the lowest air consumption. The results obtained ensure a significant reduction of sterile air consumption. Results of simulations have been validated with empirical tests
COMPUTATIONAL FLUID DYNAMICS SIMULATION OF SLOSHING INSIDE BEVERAGE CANS ON A ROTARY FILLING MACHINE
No full text
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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