1,721,061 research outputs found
Simulation-based optimization of electrohydrodynamic drying of biological materials
Get PDFLAUREA MAGISTRALEElectrohydrodynamic (EHD) drying is an effective non-thermal drying
technology. Here the dehydration rate of the food product is enhanced by
invoking ionic wind via a high voltage difference between the emitter and
collector electrodes. Among various conventional emitter-collector
configurations used for EHD drying, the wire-to-mesh configuration has recently
been found to be promising in terms of drying kinetics, drying uniformity and
scalability, compared to the conventional wire-to-plate configuration. This study
aims to further enhance the potential of this promising collector design for EHD
drying, by providing a next step in improving the collector electrode, to speed up
the drying rate and increase. Mechanistic modeling is used to build a more
realistic model of the mesh collector than currently used. In the first part, the
major driving force for EHD drying are gathered and discussed, as a basis for
further model improvements and to get an increased insight in this promising but
complex drying technology. In the second part of this computational-theoretical
study, the impact of various mesh parameters (wire diameter, wire number and
porosity) on the electric field intensity, the resulting Coulomb force on the air flow
and the drying rate was explored. To identify tradeoffs between drying rate,
energy consumption and fluid mechanic losses, an EHD performance number is
introduced. This allows having a comprehensive evaluation of energy efficiency
and drying effectiveness of different device designs. In the last part, a more
optimal mesh configuration is proposed that improves the overall EHD drying
performance number. This improvement was achieved by using a lower number
of conducting wires. Their number was chosen in such a way that an
intensification of the electric field was obtained, based on an in-depth analysis of
the electrostatic conditions. With this optimal configuration, a similar drying rate
was obtained, but the resulting energy consumption was reduced with almost a
factor 10. This improved mesh collector design is an important step towards EHD
drying devices that are scalable to industrial scale, which are sufficiently clean
and efficientElectrohydrodynamic (EHD) drying is an effective non-thermal drying
technology. Here the dehydration rate of the food product is enhanced by
invoking ionic wind via a high voltage difference between the emitter and
collector electrodes. Among various conventional emitter-collector
configurations used for EHD drying, the wire-to-mesh configuration has recently
been found to be promising in terms of drying kinetics, drying uniformity and
scalability, compared to the conventional wire-to-plate configuration. This study
aims to further enhance the potential of this promising collector design for EHD
drying, by providing a next step in improving the collector electrode, to speed up
the drying rate and increase. Mechanistic modeling is used to build a more
realistic model of the mesh collector than currently used. In the first part, the
major driving force for EHD drying are gathered and discussed, as a basis for
further model improvements and to get an increased insight in this promising but
complex drying technology. In the second part of this computational-theoretical
study, the impact of various mesh parameters (wire diameter, wire number and
porosity) on the electric field intensity, the resulting Coulomb force on the air flow
and the drying rate was explored. To identify tradeoffs between drying rate,
energy consumption and fluid mechanic losses, an EHD performance number is
introduced. This allows having a comprehensive evaluation of energy efficiency
and drying effectiveness of different device designs. In the last part, a more
optimal mesh configuration is proposed that improves the overall EHD drying
performance number. This improvement was achieved by using a lower number
of conducting wires. Their number was chosen in such a way that an
intensification of the electric field was obtained, based on an in-depth analysis of
the electrostatic conditions. With this optimal configuration, a similar drying rate
was obtained, but the resulting energy consumption was reduced with almost a
factor 10. This improved mesh collector design is an important step towards EHD
drying devices that are scalable to industrial scale, which are sufficiently clean
and efficien
Digital twins enable the quantification of the trade-offs in maintaining citrus quality and marketability in the refrigerated supply chain.
No full textSupply chains of fresh fruit must maintain a very narrow window of hygrothermal conditions after harvest. Any excursions outside this range can markedly lower the consumer acceptability of the fruit. However, the loss in fruit quality and marketability largely remains invisible to stakeholders throughout the supply chain. Here we developed a physics-based digital twin of citrus fruit to pinpoint when, why and to what extent fruit quality and marketability are reduced. Sensor data on 47 commercial shipments are thereby translated into actionable metrics for supply chain stakeholders by mapping the variability using principal component analysis. We unveiled a large spread (between 3% and 60%) in the shipments for different metrics of quality and marketability. Half of the shipments currently lie outside the ideal trade-off range between maintaining quality, killing fruit fly larvae and avoiding chilling injury. The digital twin technology opens the possibility to obtain the real-time coupling with sensor data to monitor food quality and marketability
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Exploring the thermally-controlled fentanyl transdermal therapy to provide constant drug delivery by physics-based digital twins.
Get PDFTransdermal drug delivery is suitable for low-molecular-weight drugs with specific lipophilicity, like fentanyl, which is widely used for cancer-induced pain management. However, fentanyl's transdermal therapy displays high intra-individual variability. Factors like skin characteristics at application sites and ambient temperature contribute to this variation. In this study, we developed a physics-based digital twin of the human body to cope with this variability and propose better adapted setups. This twin includes an in-silico skin model for drug penetration, a pharmacokinetic model, and a pharmacodynamic model. Based on the results of our simulations, applying the patch on the flank (side abdominal area) showed a 15.3% higher maximum fentanyl concentration in the plasma than on the chest. Additionally, the time to reach this maximum concentration when delivered through the flank was 19.8 h, which was 10.3 h earlier than via the upper arm. Finally, this variation led to an 18% lower minimum pain intensity for delivery via the flank than the chest. Moreover, the impact of seasonal changes on ambient temperature and skin temperature by considering the activity level was investigated. Based on our result, the fentanyl uptake flux by capillaries increased by up to 11.8% from an inactive state in winter to an active state in summer. We also evaluated the effect of controlling fentanyl delivery by adjusting the temperature of the patch to alleviate the pain to reach a mild pain intensity (rated three on the VAS scale). By implementing this strategy, the average pain intensity decreased by 1.1 points, and the standard deviation for fentanyl concentration in plasma and average pain intensity reduced by 37.5% and 33.3%, respectively. Therefore, our digital twin demonstrated the efficacy of controlled drug release through temperature regulation, ensuring the therapy toward the intended target outcome and reducing therapy outcome variability. This holds promise as a potentially useful tool for physicians
Advanced computational modelling for drying processes - a review
No full textDrying is one of the most complex and energy-consuming chemical unit operations. R&D efforts in drying technology have skyrocketed in the past decades, as new drivers emerged in this industry next to procuring prime product quality and high throughput, namely reduction of energy consumption and carbon footprint as well as improving food safety and security. Solutions are sought in optimising existing technologies or developing new ones which increase energy and resource efficiency, use renewable energy, recuperate waste heat and reduce product loss, thus also the embodied energy therein. Novel tools are required to push such technological innovations and their subsequent implementation. Particularly computer-aided drying process engineering has a large potential to develop next-generation drying technology, including more energy-smart and environmentally-friendly products and dryers systems. This review paper deals with rapidly emerging advanced computational methods for modelling dehydration of porous materials, particularly for foods. Drying is approached as a combined multiphysics, multiscale and multiphase problem. These advanced methods include computational fluid dynamics, several multiphysics modelling methods (e.g. conjugate modelling), multiscale modelling and modelling of material properties and the associated propagation of material property variability. Apart from the current challenges for each of these, future perspectives should be directed towards material property determination, model validation, more complete multiphysics models and more energy-oriented and integrated "nexus" modelling of the dehydration process. Development of more user-friendly, specialised software is paramount to bridge the current gap between modelling in research and industry by making it more attractive. These advanced computational methods show promising perspectives to aid developing next-generation sustainable and green drying technology, tailored to the new requirements for the future society, and are expected to play an increasingly important role in drying technology R&D. © 2014 Elsevier Ltd.status: Publishe
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