Computer-aided engineering (CAE) can benefit food product, process and equipment design by enabling mechanistic understanding and speeding up optimization. This article provides a comprehensive big ...picture of CAE in terms of its conceptual frameworks, challenges, developments under way, and achievements so far. While not intended to be a comprehensive review of all models, the article focuses on mechanistic (physics-based as opposed to data-driven) models that apply to the transformations inside the solid food itself (as opposed to its processing environment) that could perhaps also be captured by the term “product engineering.” This article also leans on the practical aspects of implementation of CAE in a food product context by focusing on approaches and workarounds possible today. Framework discussions go beyond product modeling to its quality and safety modeling. While generic software tools have become more powerful and easy to use, in order to use them for food applications, one needs a framework for modeling various food process, quality and safety that provides an appropriate mathematical description of the reality. Challenges in implementing the frameworks and the workarounds are presented. The goal here is to help widen acceptance of the CAE approach in both research and education in the food sector, helping it reap the benefits of CAE like other sectors.
•CAE of food can be based on a transport model in a multiphase, multicomponent, deformable porous medium.•Process, quality and safety models can be tied together using frameworks reported.•Modeling community, tools, and complementary experimentation possibilities have reached a critical mass.
Bread baking – A review Mondal, Arpita; Datta, A.K.
Journal of food engineering,
06/2008, Letnik:
86, Številka:
4
Journal Article
Recenzirano
Bread is a basic dietary item dating back to the Neolithic era, which is prepared by baking that is carried out in oven. Control of the production and distribution of bread has been used as a means ...of exercising political influence over the populace for at least the last two millennia. Several experimental and mathematical models are developed for clear understanding of baking. This article presents a review of published literatures on experimental and mathematical studies on bread baking during the last two decades. Baking technology, evolution of baking ingredients, thermophysical properties of bread as functions of moisture content and baking time are reviewed. Experimental and simulative studies on profiling of temperature, moisture content, pore volume, expansion ratio during baking are also reviewed.
A more general multiphase porous media model is shown to effectively describe a number of heat and mass transfer processes in foods, particularly processes involving internal evaporation. Results ...from application of such a model to convective heating, baking (with and without volume change), frying and microwave heating are included. Limitations of such models in applying to foods include lack of availability of input parameters to such models and the lack of implementation in commercially available software.
The objective of this study was to investigate the process of generating hydrogen rich syngas through thermo chemical fluidized bed gasification of biomass. The experiments were performed in a ...laboratory scale externally heated biomass gasifier. Rice husk had been taken as a representative biomass and, steam had been used as the fluidizing and gasifying media. A thermodynamic equilibrium model was used to predict the gasification process. The work included the parametric study of process parameters such as reactor temperature and steam biomass ratio which generally influence the percentage of hydrogen content in the product gas. Steam had been used here to generate nitrogen free product gas and also to increase the hydrogen concentration in syngas with a medium range heating value of around 12
MJ/Nm
3.
The H I 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection ...of this signal. This paper investigates the extragalactic point source contamination and how accurately bright sources (1 Jy) must be removed in order to detect 21 cm emission with upcoming radio telescopes such as the Murchison Widefield Array. We consider the residual contamination in 21 cm maps and power spectra due to position errors in the sky model for bright sources, as well as frequency-independent calibration errors. We find that a source position accuracy of 0.1 arcsec will suffice for detection of the H I power spectrum. For calibration errors, 0.05% accuracy in antenna gain amplitude is required in order to detect the cosmic signal. Both sources of subtraction error produce residuals that are localized to small angular scales, k 0.05 Mpc--1, in the two-dimensional power spectrum.
Large-area X-ray imaging is one of the most widely used imaging modalities that spans several scientific and technological fields. Currently, the direct X-ray conversion materials that are being ...commercially used for large-area (> 8 cm × 4 cm without tiling) flat panel applications, such as amorphous selenium (a-Se), have usable sensitivities of up to only 30 keV. Although there have been many promising candidates (such as polycrystalline HgI
and CdTe), none of the semiconductors were able to assuage the requirement for high energy (> 40 keV) large-area X-ray imaging applications due to inadequate cost, manufacturability, and long-term performance metrics. In this study, we successfully demonstrate the potential of the hybrid Methylammonium lead iodide (MAPbI
) perovskite-based semiconductor detectors in satisfying all the requirements for its successful commercialization in synchrotron and medical imaging. This new generation of hybrid detectors demonstrates low dark current under electric fields needed for high sensitivity X-ray imaging applications. The detectors have a linear response to X-ray energy and applied bias, no polarization effects at a moderate bias, and signal stability over long usage durations. Also, these detectors have demonstrated a stable detection response under BNL's National Synchrotron Light Source II (NSLS-II) 70 keV monochromatic synchrotron beamline.
The growing concern for energy, economy and environment calls for an efficient utilization of natural energy resources in developing useful work. An important thermodynamic aspect in gauging the ...overall energy economy of any physical process is the combined energy and exergy analysis from the identification of process irreversibilities. The present paper makes a comprehensive review pertaining to fundamental studies on thermodynamic irreversibility and exergy analysis in the processes of combustion of gaseous, liquid and solid fuels. The need for such investigations in the context of combustion processes in practice is first stressed upon and then the various approaches of exergy analysis and the results arrived at by different research workers in the field have been discussed. It has been recognized that, in almost all situations, the major source of irreversibilities is the internal thermal energy exchange associated with high-temperature gradients caused by heat release in combustion reactions. The primary way of keeping the exergy destruction in a combustion process within a reasonable limit is to reduce the irreversibility in heat conduction through proper control of physical processes and chemical reactions resulting in a high value of flame temperature but lower values of temperature gradients within the system. The optimum operating condition in this context can be determined from the parametric studies on combustion irreversibilities with operating parameters in different types of flames.
As people age and require more assistance with daily living and health needs, a range of housing and care options is available. Over the past four decades the market for seniors housing and ...care-including assisted living and independent living communities-has greatly expanded to accommodate people with more complex needs. These settings provide housing in a community environment that often includes personal care assistance services. Unfortunately, these settings are often out of the financial reach of many of this country's eight million middle-income seniors (those ages seventy-five and older). The private seniors housing industry has generally focused on higher-income people instead. We project that by 2029 there will be 14.4 million middle-income seniors, 60 percent of whom will have mobility limitations and 20 percent of whom will have high health care and functional needs. While many of these seniors will likely need the level of care provided in seniors housing, we project that 54 percent of seniors will not have sufficient financial resources to pay for it. This gap suggests a role for public policy and the private sector in meeting future long-term care and housing needs for middle-income seniors.
The role of a carousel in improving heating uniformity of food in a microwave oven is studied. A physics-based computational model is developed coupling the Maxwell’s equations for electromagnetics ...and energy equation for heating inside a microwave oven with food load. The model is solved numerically using a finite element based computational software. Transient simulation of the heating process is done by considering the rotation of the turntable by repeating the computations for discrete angular positions of the turntable. The model is experimentally validated by measurements of point temperatures using fiber optic probes. Power absorbed in the food as a function of the angle of rotation of the turntable covering the entire cycle is available for the first time. Using various measures of heating uniformity, it is shown that the carousel helps in increasing the temperature uniformity of the food by about 40%.
External control of a genetic regulatory network is used for the purpose of avoiding undesirable states, such as those associated with disease. Heretofore, intervention has focused on finite-horizon ...control, i.e., control over a small number of stages. This paper considers the design of optimal infinite-horizon control for context-sensitive probabilistic Boolean networks (PBNs). It can also be applied to instantaneously random PBNs. The stationary policy obtained is independent of time and dependent on the current state. This paper concentrates on discounted problems with bounded cost per stage and on average-cost-per-stage problems. These formulations are used to generate stationary policies for a PBN constructed from melanoma gene-expression data. The results show that the stationary policies obtained by the two different formulations are capable of shifting the probability mass of the stationary distribution from undesirable states to desirable ones.
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