Moisture Distribution Profiles Research Articles

Elucidating the effect of various roasting methods on the water-holding capacity and volatile flavor profiles of ultrasound-assisted pickled roast duck meat

The present study investigated the impact of various roasting methods (OV: Oven, AF: Air Fryer, CO: Combined steaming and roasting oven) on the color, water-holding capacity (WHC), texture characteristics, moisture distribution and volatile flavor profile of ultrasound-assisted pickled roast duck. In comparison to the OV and AF roasting methods, the CO roasting method resulted in roasted duck with excellent color, higher WHC, and improved tenderness, as evidenced by the significant increase in myofibrillar fragmentation index value (P < 0.05), the transformation of β-sheet structure into random coil and the reduction in moisture migration. Several characteristic flavor compounds such as benzaldehyde, pentanal, and hexanal were enriched in the CO treatment. The composition of fatty acids corroborated this result. On the other hand, compared to static pickling, duck meat subjected to ultrasound-assisted pickling showed greater improvements in texture and WHC while significantly increasing fatty acid content, playing a crucial role in the formation of roast duck flavor. In addition, ultrasound-assisted pickling increased malondialdehyde formation but did not cause intense lipid oxidation. In conclusion, ultrasound-assisted pickling and the CO roasting method effectively improved the color, WHC and promoted the release of volatile flavor compounds in roasted duck. This finding offered new avenues and theoretical references for the development of the roasted duck industry.

Indirect mode solar drying of stevia (Stevia rebaudiana) leaves: experimental and numerical investigation of fluid flow pattern, moisture, and temperature distribution profile

Indirect mode solar drying of stevia (Stevia rebaudiana) leaves: experimental and numerical investigation of fluid flow pattern, moisture, and temperature distribution profile

Heat consumption and modeling of corn seeds intermittent drying

AbstractBackgroundCorn seed is produced on a large scale, and as production is carried out seasonally, the storage is needed to supply uninterrupted demand. To carry out the storage, as the material from the harvest has a high initial moisture content, it is necessary to carry out the drying process. In order to reduce energy consumption, an alternative is intermittent drying. The purpose of this article is to fit the mathematical model of intermittent drying by distributed parameters, based on experimental data of temperature and moisture content of corn seeds submitted to intermittent drying, to determine the diffusivity value and to assess heat consumption.ResultsFor samples dried to the final moisture content of 16.0% on dry basis (d.b.), the condition of intermittent drying at a temperature of 40°C and 10 min of tempering period led to the lowest heat consumption, in comparison to conventional drying and to intermittent drying under higher temperatures. In addition, to obtain a final moisture content of 14.0% (d.b.), the conventional drying condition at 55°C resulted in the lowest heat consumption, compared to the other drying conditions. The distributed parameter model can predict the experimental data with a global deviation lower than 10.0%.ConclusionAnalyzing the moisture distribution profiles for the corn seeds, it was verified that there was a difference in the moisture content along the position inside the material, being necessary to evaluate the influence of moisture distribution along the position inside the material in kinetic drying models.

The impact of freezing methods on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton during long-term frozen storage

The aim of present study was to investigate the influence of conventional freezing (CF, −18 °C), low-temperaturefreezing (LF, −40 °C), and ultra-low-temperature freezing (ULF, −80 °C) on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton (HGM) during frozen storage (0, 30, 60, 90, 120, 150 and 180 days). The TPC, TVB-N, and TBARS values increased significantly with prolonged storage, while the moisture content decreased (P < 0.05). Additionally, the concentrations of aldehydes, alcohols, ketones, acids, and alkenes decreased significantly as the storage duration increased. However, the concentrations of esters and heterocyclics increased (P < 0.05). Notably, at 30–180 days of storage, the TBARS and TVB-N values in ULF samples were significantly lower than those in CF and LF samples, while the moisture content was significantly higher (P < 0.05). Low field-nuclear magnetic resonance (LF-NMR) analysis showed that ULF decreased water migration and maintained the original texture characteristics of HGM during frozen storage. The ULF and LF groups had significantly higher levels of volatiles than the CF group (P < 0.05). The findings show that ULF, with its relatively rapid freezing rates, can still maintain the high quality of HGM after 180 days of frozen storage, contributing to quality control.

Hygrothermal effects on the nonlinear buckling of functionally graded multilayer GPL‐Fiber reinforced hybrid composite cylindrical shells

AbstractAn accurate nonlinear buckling analysis of functional graded multilayer GPL‐Fiber reinforced hybrid composites (FG multilayer GPL‐Fiber RHCs) cylindrical shells under hygro‐thermo‐mechanical loadings is performed. The axisymmetric pre‐buckling effect, which is usually neglected in the classical eigen‐buckling analysis, is considered to improve the accuracy of critical buckling loads. Nonlinear governing equations are derived by adopting the high‐order shear deformation theory and Novozhilov's nonlinear shell theory. Accurate critical buckling loads and explicit buckling mode shapes are obtained by the Galerkin method. Comparisons with results of existing literature are presented to validate the accuracy of present solutions. A comprehensive parametric study of key influencing parameters on the structural stability of the FG multilayer GPL‐Fiber RHCs cylindrical shell is investigated in detail. The numerical results indicate that the stability of such shell highly depends on the temperature rise and moisture absorption, and contents and distribution profiles of GPLs and fibers could be optimized to enhance the anti‐buckling performance of the shell.

Modeling of Forced and Natural Convection Drying Process of a Coffee Seed

HighlightsThe forced and natural convection drying processes of a single coffee grain can be predicted.The moisture distribution profiles depict the drying phenomena and water concentration zones.With accurate predictive drying curves, coffee growers can ensure high-quality coffee beans.Abstract. Different coffee drying technologies face complex tasks in ensuring an acceptable final seed moisture content. This research performed a Finite Element Analysis (FEA) study, simulating a single coffee bean's drying process as a transient mass diffusion model under mechanical and natural convection conditions, so the drying behavior and data of both case scenarios can be foreseen and controlled by a predictive Finite Element Model (FEM). A wet bean was 3D-scanned and digitized as the FEA simulation geometry; the water diffusion between the grain and the atmosphere was defined by a diffusion coefficient subject to the drying air temperature and the grain's moisture content. Three cases were studied: mechanical grain drying at three different temperatures (50, 45, and 40°C) in a forced convection environment; variable natural convection drying under environmental conditions (wet and dry season); and constant natural convection (wet and dry season), including the variation in day/night temperature and relative humidity. The results agree well with the data found in the literature, obtaining the graphical moisture distribution of the phenomena, predictive drying curves, diffusion coefficients, and isotherms. Both simulated drying scenarios provide essential information for coffee growers to improve and control their drying processes, thus obtaining high-quality grains, reducing contamination by microorganisms, and ensuring the integrity of their products. Keywords: Coffea arabica, Coffee Drying, Coffee Seed, Finite Element Model, Moisture Diffusion.

Irrigation management model based on soil moisture distribution profile

The article is devoted to the actual problem solving of precision irrigation in terms of an irrigation management model creating based on the soil moisture spatial variation. The research key element is that the model being created takes into account the soil moisture content variability not according the area of the irrigated plot, but in the vertical profile of the agricultural crops active root water consumption zone. This approach avoids the necessity for the irrigation equipment design complication for irrigation moisture differentiated distribution and therefore the technology application allows us to avoid unnecessary costs. The irrigation requirement assessing block according to the moisture content differentiating in the active soil layer profile is new in the proposed model architecture. The block algorithm assumes the two-stage irrigation requirement assessment, first, based on the total level of soil moisture variation in the active layer profile and second, on the layers sum of the active soil horizon with a moisture content below the threshold level. Together, these estimates allow us to make a decision about the irrigation necessity if soil moisture excessive variation in the profile layers and the moisture distribution nature in the soil profile have a significant impact on the irrigated crop productivity.

Prediction of climate specific vertical movement of pavements with expansive soils based on long-term 2D numerical simulation of rainwater infiltration

Long-term 2D simulation of rainwater infiltration into road embankments built on expansive soils is lacking in most highway design strategies. This paper explores the application of Hydrus-2D to establish a finite element model capable of performing long-term simulations of water flow in road embankments subjected to seasonal rainfall. Toward that end, climate specific suction profiles are generated from the simulations using real time climate data, which are used to predict vertical movement at the pavement edge. Sensitivity analyses show that the initial moisture condition has the most significant effect on moisture distribution and suction profile patterns. This induces a maximum decrease in vertical movement of 3.0 cm when a dry initial moisture state is compared with a wet initial moisture state. Higher values of evaporation rate and hydraulic conductivity result in less long-term vertical movement, although the impact is less obvious compared to initial moisture condition. The results also indicate that an extreme rain event can double the vertical displacement of pavements when compared to normal rain events, which proves the importance of using real climate data when expansive soils are involved. A case study presented the advantages of using Hydrus-2D suction profiles to predict vertical movement of pavements.

SIMULATION OF SODIUM AND POTASSIUM DYNAMICS BY THE HYDRUS 2D MODEL IN A HAPLIC PLANOSOL VIA RESIDUE WATER

ABSTRACT The application of chemical substances to the soil together with little attention given to the possible environmental impacts, transformed the environment into a recipient of waste. The aim of this study was to simulate the movement of water and solutes (sodium and potassium together) using the STANMOD and HYDRUS-2D models in a typical Haplic Planosol under the application of wastewater via surface irrigation under different flow rates. The experiment was conducted in the laboratory by miscible displacement tests, first using columns with deformed soil under saturation and steady water flow conditions, at a rate of 11.7 cm3 min-1, to obtain transport parameters of sodium and potassium ions, and in the applied residual water, the values of 475 and 76.6 mg dm-3, respectively. The transport parameters were estimated from the numerical adjustment of effluent distribution curves, using the STANMOD model. In a second step, the HYDRUS-2D model was applied to simulate the volumetric soil moisture distribution profiles, as well as the ion concentrations in the wet bulb. Considering the results obtained, we can see that there was considerable interaction between the solutes and the soil. The value of the delay parameter was higher for the sodium when compared to the potassium, reflecting its greater adsorption and the processes of exchange between the solute and the soil. The results suggested the need for adequate soil management in order to avoid future soil sodification and, in view of the application of HYDRUS-2D, it was verified that the model presented a satisfactory performance in the simulation of the displacement of the ions, after 1, 5 and 10 hours of wastewater application.

Non-destructive investigation of cellular level moisture distribution and morphological changes during drying of a plant-based food material

This study investigates the complex microstructural changes and cell-level water transportation in plant-based food materials during drying, using X-ray micro-computed tomography (X-ray μCT). The investigations were performed on apple tissue to uncover the cellular level moisture distribution and the structural changes during convective drying at 50 °C, 60 °C, and 70 °C. Image analysis revealed that significant changes occurred in moisture content, and cell and pore size distribution with drying time and temperature. The moisture content determined using the X-ray μCT images was compared with that determined by the electronic moisture analyser (EMA) and good agreement was found. The results show a strong relationship between drying temperature, pore formation and deformation of the food material. At high drying temperature, the pore formation increased, which led to reduced shrinkage of the food material. The porosity of a sample of dried apple increased by 35% as drying temperature increased from 50 °C to 70 °C. However, a significant amount of cell rupture was observed during drying at the higher temperature. The cellular level moisture distribution profile confirmed that a traceable amount of water was still present in the centre cells of the tissue although the sample was deemed dried from the bulk moisture analysis. The findings of this study substantially enhance our understanding of instantaneous cellular level moisture distribution in a food sample over the time of drying.

The Effect of Temperature on Moisture Transport in Concrete.

Most concrete structures and buildings are under temperature and moisture variations simultaneously. Thus, the moisture transport in concrete is driven by the moisture gradient as well as the temperature gradient. This paper presents an experimental approach for determining the effect of different temperature gradients on moisture distribution profiles in concrete. The effect of elevated temperatures under isothermal conditions on the moisture transport was also evaluated, and found not to be significant. The non-isothermal tests show that the temperature gradient accelerates the moisture transport in concrete. The part of increased moisture transfer due to the temperature gradient can be quantified by a coupling parameter DHT, which can be determined by the present test data. The test results indicated that DHT is not a constant but increases linearly with the temperature variation. A material model was developed for DHT based on the experimental results obtained in this study.

Experimental investigation of bound and free water transport process during drying of hygroscopic food material

Hygroscopic food materials contain free (FW) and bound (BW) water in different cellular environments. In-depth understanding of the mechanisms of moisture migration from different cellular environments during drying is crucial for optimising heat and mass transfer as well as for obtaining better quality dried foods. Therefore, the main aim of the present work is to investigate the transportation mechanisms of FW and BW during drying. Experiments were performed on the potato tissue using 1H-NMR T2 relaxometry to uncover the mechanisms involved in FW and BW transportation. The results have confirmed the view that BW migrates after the rupture of the cell membranes. It is interesting to highlight that the cell membranes rupture at different stages of drying rather than collapsing at one time. The membrane collapse depends predominantly on the penetration rate of heat energy and the pressure gradient between intracellular and intercellular environments. All test results suggest that most of the cell membranes rupture at the middle stage of drying where the moisture content is about 2–4 kg/kg (db.). Furthermore, the moisture distribution profile confirmed that some moisture remained around the centre of the dried sample although the surface of the sample became dry.

Moisture conditioning of wood using a continuous microwave dryer

ABSTRACTLower moisture content in wood, preferably 5–6%, is desirable for many chemical modification reactions. Economically, it is not feasible to dry timber to such low moisture content by conventional drying without drying degrades. Microwave heating was evaluated and found to be effective in reducing the moisture content of radiata pine from 13% to 6% in a microwave cycle of two minutes. The energy consumption is about 55 kWh/m3. Moisture distribution profiles demonstrate very uniform drying across the sample thickness. The findings suggest that microwave heating can potentially be applied to condition wood in a very short period of time.

Validation of a coupled heat, vapour and liquid moisture transport model for porous materials implemented in CFD

Moisture-related damage is an important issue when looking at the performance of building envelopes. In order to accurately predict the moisture behaviour of building components, building designers can resort to Heat, Air and Moisture (HAM) models. In this paper a newly developed heat and mass transfer model that is implemented in a 3D finite volume solver, Fluent®, is presented. This allows a simultaneous modelling approach of both the convective conditions surrounding a porous material and the heat and moisture transport in the porous material governed by diffusion. Unlike most HAM models that often confine to constant convective transport coefficients it is now possible to better predict these convective boundary conditions. An important application of the model is the convective drying of porous building materials. Especially during the first drying stage, the drying rate is determined by the convective boundary conditions. The model was validated against a convective drying experiment from literature, in which a saturated ceramic brick sample is dried by flowing dry air over one side of the sample surface. Temperature and relative humidity measurements at different depths in the sample, moisture distribution profiles and mass loss measurements were compared with simulation results. An overall good agreement between the coupled model and the experiments was found, however, the model predicted the constant drying rate period better than the falling rate period. This was improved by adjusting the material properties. The adjustment of the material properties was supported by neutron radiography measurements.

Experimental Study of Strengthening an RC Bridge Deck by Adding a Concrete Overlay

ABSTRACTThe present contribution focuses on the experimental investigation of moisture distribution profiles of a reinforced concrete bridge deck determined before, during and after adding a concrete overlay. By means of a non‐destructive system, the mass water content distributions were measured in the existing bridge deck as well as in the concrete overlay. Furthermore, the in situ measurements were accompanied by a comprehensive laboratory test programme. Water desorption isotherms and ultimate drying shrinkage strain were determined on specimens made of both the substrate and overlay concrete. Moreover, moisture distributions and shrinkage strains were measured on concrete prisms stored under uniform climatic conditions. Comparison of in situ measurements with lab test results allows a better understanding of the impact of environmental influences on the bonded overlay behaviour. Comparison of in situ measurements with previous lab test results allows the assessment of the effectivity of surface preparation by high‐pressure water jetting and, hence, the examination of the significance of results from composite lab tests for real bridge decks strengthened by overlays. A comparison of an experimental and numerical study of restraint effects exerted from the substrate concrete on the overlay will be presented in an accompanying paper.

Analytical solution for heat and moisture diffusion in layered materials

The study of heat and moisture flows in multiple layers of different materials that make up the unsaturated zone is of great importance when characterizing the behaviour of these materials. In the present paper, analytical solutions of the one-dimensional heat and moisture coupled diffusion problem for layered materials under two different sets of boundary conditions are proposed. The coupled flow of heat and moisture are assumed to follow the theory of Philip and De Vries, and the solutions are derived analytically using integral transform methods. A comparison between the analytical and numerical solutions for one example problem shows satisfactory results. Furthermore, a procedure is presented for estimating heat and moisture distribution profiles in any layered materials using the derived analytical solutions. It is expected that the proposed analytical solutions will be used effectively for preliminary analyses of coupled heat and moisture movements in unsaturated porous media.

Predicting moisture transfer and shelf-life of multidomain food products

A mathematical model based on Fick’s second law was developed to predict the unidirectional moisture transfer in multidomain food products under realistic conditions with non perfect contact between components and variable storage temperature. Effective moisture diffusivity dependence on moisture content and temperature was determined using independent moisture sorption experiments in a controlled atmosphere microbalance and in a diffusion cell. Local moisture distribution profiles were measured for several storage times in a food system constituted of a sponge cake and an agar gel separated by an air gap. A good fit between experimental and predicted values was observed for varying air gap sizes and varying storage temperatures (5, 20 and 30 °C). Temperature abuse during storage of a multidomain food product increased moisture movement, but the presence of a thin air gap between components increased the ability of a multidomain food product to withstand temperature fluctuations.

Development of an electrical time domain reflectometry (ETDR) distributed moisture measurement technique for porous media

In this paper, a novel electrical time domain reflectometry (ETDR) measurement technique capable of measuring moisture distribution profile in a porous medium is presented. A signal calibration algorithm to interpret the ETDR waveform based on an empirical relation between moisture content and differential impedance of the medium was developed. The transient distribution of the moisture content in a concrete block covered with fibre reinforced polymer laminate on one end surface was experimentally measured. The experimental results were then compared with the solution of a finite element analysis. Good agreement was shown for the trend of the transient moisture distribution profile. It was demonstrated that the ETDR distributed moisture sensor developed in the current study was capable of measuring the variation of the moisture content distribution in a porous medium.

Analysis of Drying Kinetics and Moisture Distribution in Convective Textile Fabric Drying

ABSTRACT The drying process of crude cotton fabric is analyzed under two main aspects: analysis of moisture distribution inside the textile sheet, and analysis of certain operational convective drying process variables. Experimental apparatus consisted of a drying chamber in which samples of pure cotton textile were suspended inside the drying chamber and exposed to a convective hot air flow. The influence of the operational variables on the drying process behavior was studied by two different ways with generalized drying curves. The behavior of moisture distribution profiles was compared to average moisture content of the textile fabric verifying whether average values were able to represent the textile moisture content during the drying process.

Edible acetylated monoglyceride films: Effect of film‐forming technique on moisture barrier properties

AbstractThe influence of film‐forming techniques on the moisture barrier efficiency of acetylated MG (AMG) films tested in real conditions at the interface between an agar gel (AG) and sponge cake (SC) was investigated. Three systems were studied: self‐supporting films, sprayed films, and cast films. The moisture distribution profiles of the AG/AMG/SC systems were determined experimentally and by using a predictive model for both self‐supporting films of various thicknesses and formed‐in‐place (sprayed or cast) films. Increasing the thickness of the self‐supporting films had no influence on moisture barrier efficiency, probably due to the high stability of the AMG material. Formed‐in‐place films were 40% less efficient than the self‐supporting films whatever the application procedure used (spraying or casting) because of their poor integrity due to the roughness of the SC surface.