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521.
Multiscale modeling in food engineering 总被引:1,自引:0,他引:1
Quang T. Ho Jan Carmeliet Ashim K. Datta Thijs Defraeye Mulugeta A. Delele Els Herremans Linus Opara Herman Ramon Engelbert Tijskens Ruud van der Sman Paul Van Liedekerke Pieter Verboven Bart M. Nicolaï 《Journal of food engineering》2013
Since many years food engineers have attempted to describe physical phenomena such as heat and mass transfer that occur in food during unit operations by means of mathematical models. Foods are hierarchically structured and have features that extend from the molecular scale to the food plant scale. In order to reduce computational complexity, food features at the fine scale are usually not modeled explicitly but incorporated through averaging procedures into models that operate at the coarse scale. As a consequence, detailed insight into the processes at the microscale is lost, and the coarse scale model parameters are apparent rather than physical parameters. As it is impractical to measure these parameters for the large number of foods that exist, the use of advanced mathematical models in the food industry is still limited. A new modeling paradigm – multiscale modeling – has appeared that may alleviate these problems. Multiscale models are essentially a hierarchy of sub-models which describe the material behavior at different spatial scales in such a way that the sub-models are interconnected. In this article we will introduce the underlying physical and computational concepts. We will give an overview of applications of multiscale modeling in food engineering, and discuss future prospects. 相似文献
522.
Steven C. Gauci Marvin Gernhardt Hendrik Frisch Hannes A. Houck James P. Blinco Eva Blasco Bryan T. Tuten Christopher Barner-Kowollik 《Advanced functional materials》2023,33(39):2206303
To advance the applications of direct laser writing (DLW), adaptability of the printed structure is critical, prompting a shift toward printing structures that are comprised of different materials, and/or can be partially or fully erased on demand. However, most structures that contain these features are often printed by complex processes or require harsh developing techniques. Herein, a unique photoresist for DLW is introduced that is capable of printing 3D microstructures that can be erased by exposure to darkness. Specifically, microstructures based on light-stabilized dynamic materials are fabricated that remain stable when continously irradiated with green light, but degrade once the light source is switched off. The degradation and light stabilization properties of the printed materials are analyzed in-depth by time-lapse scanning electron microscopy. It is demonstrated that these resists can be used to impart responsive behavior onto the printed structure, and –critically– as a temporary locking mechanism to control the release of moving structural features. 相似文献
523.
Formation Energy Profiles of Oxygen Vacancies at Grain Boundaries in Perovskite-Type Electroceramics
Daniel Mutter Cong Tao Daniel F. Urban Christian Elsässer 《Advanced Engineering Materials》2023,25(18):2201847
Oxygen vacancy formation energies play a major role in the electric field-assisted abnormal grain growth of technologically relevant polycrystalline perovskite phases. The underlying effect on the atomic scale is assumed to be a redistribution of cationic and anionic point defects between grain boundaries (GBs) and the bulk interior regions of the grains due to different defect formation energies in the structurally different regions, accompanied by the formation of space charge zones. Using atomistic calculations based on classical interatomic potentials, optimized structures of the symmetric tilt GBs Σ5(210)[001] and Σ5(310)[001], and of the asymmetric tilt GB (430)[001]||(100)[001] in the electroceramic perovskite materials SrTiO3, BaTiO3, and BaZrO3, are derived and discussed. Profiles of oxygen vacancy formation energies across those GBs are presented and their dependence on composition and GB type is discussed. 相似文献
524.
The ordered body-centered tetragonal intermetallic phase of FeNi is a promising candidate for high-performance permanent magnets without rare-earth elements. However, on earth FeNi is found naturally only in the disordered face-centered-cubic A1 phase. Herein, the atomic migration and ordering processes in binary intermetallic phases are investigated within the framework of density-functional theory. The main objectives are 1) to develop a thorough understanding of the thermally activated diffusion processes at the atomic scale and 2) to make a critical assessment in how far electric field and current effects can be effective means for an enhanced hardening-by-ordering of disordered, soft-ferromagnetic alloys. The scope is extended from FeNi to the hard-ferromagnetic phases of FePt, FePd, MnAl, and MnGa as well as ternary Fe(Pt,Ni) alloys. These materials cover a wide range of thermal-ordering time scales and related experimental feasibility. 相似文献
525.
Markus Schleuning Moritz Kölbach Ibbi Ahmet Raphael Präg Ronen Gottesman René Gunder Mengyuan Zhang Dan Ralf Wargulski Daniel Abou-Ras Daniel A. Grave Fatwa F. Abdi Roel van de Krol Klaus Schwarzburg Rainer Eichberger Dennis Friedrich Hannes Hempel 《Advanced functional materials》2023,33(25):2300065
Metal oxides are considered as stable and low-cost photoelectrode candidates for hydrogen production by photoelectrochemical solar water splitting. However, their power conversion efficiencies usually suffer from poor transport of photogenerated charge carriers, which has been attributed previously to a variety of effects occurring on different time and length scales. In search for common understanding and for a better photo-conducting metal oxide photoabsorber, CuFeO2, α-SnWO4, BaSnO3, FeVO4, CuBi2O4, α-Fe2O3, and BiVO4 are compared. Their kinetics of thermalization, trapping, localization, and recombination are monitored continuously 100 fs–100 µs and mobilities are determined for different probing lengths by combined time-resolved terahertz and microwave spectroscopy. As common issue, we find small mobilities < 3 cm2V-1s-1. Partial carrier localization further slows carrier diffusion beyond localization lengths of 1–6 nm and explains the extraordinarily long conductivity tails, which should not be taken as a sign of long diffusion lengths. For CuFeO2, the localization is attributed to electrostatic barriers that enclose the crystallographic domains. The most promising novel material is BaSnO3, which exhibits the highest mobility after reducing carrier localization by annealing in H2. Such overcoming of carrier localization should be an objective of future efforts to enhance charge transport in metal oxides. 相似文献
526.
Seyed Vahid Sajadifar Philipp Krooß Marcel Krochmal Thomas Wegener Akbar Heidarzadeh Hannes Fröck Janez Zavašnik Olaf Kessler Thomas Niendorf 《Advanced Engineering Materials》2023,25(15):2300090
The effect of a novel heat treatment, that is, aging under superimposed external stress, on the fatigue performance and microstructural evolution of a high-strength aluminum alloy (EN AW-7075) is presented. Stress aging, a combination of heat treatment and superimposed external stress, can enhance the mechanical properties of EN AW-7075 under monotonic loading due to the acceleration of precipitation kinetics. Scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) reveal that a longer aging time and the presence of superimposed stress both promote the formation and growth of precipitates, that is, the precipitation of strengthening η´ precipitates. This is confirmed by differential scanning calorimetry (DSC) heating experiments of stressless and stress-aged states. Furthermore, stress aging leads to a reduction of dimensions of precipitate-free zones near grain boundaries. Cyclic deformation responses (CDRs) and half-life hysteresis loops are evaluated focusing on the low-cycle fatigue (LCF) performance of different conditions. A noticeable cyclic hardening seen in case of the specimens aged for a short time indicates the occurrence of dynamic strain aging (DSA). Eventually, stress aging allows for an enhancement of the monotonic mechanical properties of EN AW-7075 without degrading the cyclic performance in the LCF regime. 相似文献
527.
Panzer Hannes Buss Lorenz Zaeh Michael F. 《Metallurgical and Materials Transactions A》2023,54(4):1142-1158
Metallurgical and Materials Transactions A - Powder Bed Fusion of Metals using a Laser Beam (PBF-LB/M) has proven to be a competitive manufacturing technology to produce customized parts with a... 相似文献
528.
Francisco Lázaro Ronald Raulefs Hannes Bartz Thomas Jerkovits 《International Journal of Satellite Communications and Networking》2023,41(2):178-194
VDES R-Mode aims at providing a contingency maritime positioning and navigation system when the operation of Global Navigation Satellite Systems (GNSS) is disrupted. However, VDES R-Mode, similarly to GNSS, can itself also be subject to different types of attacks, such as jamming or spoofing. In this paper, we evaluate the vulnerabilities of VDES R-Mode and discuss the effectiveness and cost of different types of countermeasures. The outcome of this cost-benefit analysis is a recommendation to introduce authentication for the navigation messages of R-Mode using the Timed Efficient Stream Loss-Tolerant Authentication (TESLA) protocol. 相似文献