Moisture Content Conditions Research Articles

Storage on the vigor and viability of macauba seeds from two provenances of Minas Gerais State

ABSTRACT: Macauba palm stands out for having favorable features to biodiesel production such as the high oil content of its fruit. Considering the great potential of the species and their applicability in the renewable energy field, it becomes indispensable to establish the right conditions for storing the seeds for propagation purpose. The aim of this research was to evaluate the effect of seed moisture content, packaging, and storage conditions such as temperature and relative humidity on the quality of seeds from Minas Gerais State, during a 12-month storage period. The research had two independent assays: (I) the seeds were stored with three moisture contents/ranges 4.0≤6.0%; 6.0≤8.0% and 8.0≤10.0% in impermeable packages, under room temperature and at 10ºC; (II) seeds with approximately 5.9% of moisture content were stored in three different types of packages: a) permeable, b) semi-permeable and c) impermeable. Three storing conditions were tested: a) room temperature and RH under laboratory conditions; b) 15ºC and 45% RH; c) 20ºC and 55% RH. Water content, germination rate and germination speed index were evaluated at 0, 4, 8 and 12 months of storing. The best germination results were obtained with the moisture range of 6.0≤8.0%, with seeds kept at room temperature; while the seeds stored at 10ºC, regardless the moisture range, did not survive. The stored seeds with 5.9% moisture content and at both 15ºC/45%RH and 20ºC/55% RH conditions, independently of the package type used, showed the best results. Thus, macaw palm seeds can be classified as intermediates seeds.

Transport of sulfacetamide and levofloxacin in granular porous media under various conditions: Experimental observations and model simulations

Understanding the fate and transport of antibiotics in porous media can help reduce their contamination risks to soil and groundwater systems. In this work, batch and column experiments were conducted to determine the interactions between two representative antibiotics, sulfacetamide (SA) and levofloxacin (LEV), and sand porous media under various solution pH, humic acid (HA) concentration, grain size, and moisture content conditions. Batch sorption experimental results indicated that the sand had relatively strong bonding affinity to LEV, but little sorption of SA under different pH, HA concentration, grain size conditions. Results from the packed sand column experiments showed that SA had extremely high mobility in the porous media for all combinations of pH, HA concentration, grain size, and moisture content. The mass recovery of SA was higher than 98.5% in all the columns with the exception of the one packed with fine sand (97.2%). The retention of LEV in the columns was much higher and the recovery rates ranged from 0% to 71.1%. Decreases in solution pH, HA concentration, grain size, or moisture content reduced the mobility of LEV in the columns under the tested conditions. These results indicated that type of antibiotics and environmental conditions also played an important role in controlling their fate and transport in porous media. Mathematical models were applied to simulate and interpret experimental data, and model simulations described the interactions between the two antibiotics and sand porous media very well. Findings from this study elucidated the key factors and processes controlling the fate of SA and LEV in porous media, which can inform the prediction and assessment of the environmental risks of antibiotics.

Comparison between collet and cooking extrusions on physicochemical properties of whole grain barley

AbstractThe experiment was designed to study physicochemical properties of collet and cooking extrudates of hulless barley with different extrusion parameters: feed moisture content, screw speed, and temperature. The lightness (L*) and total color difference (ΔE) values were increased with increasing screw speed and decreasing feed moisture content in collet extrudates. The maximum shear force (MSF) decreased with the increase of temperature in collet extrusion, while MSF was increased with increasing temperature under same feed moisture content condition in cooking extrusion. The degree of gelatinization (DG) showed tendency to be increased at higher feed moisture content, lower screw speed, and higher extrusion temperature. Scanning electron microscope observation of extrudates with the lowest MSF, which was obtained from collet extrusion at 12% feed moisture content, 400 rpm screw speed, and 110 °C showed less dense structure and less un‐gelatinized starch, compared to collect extrudates that had the highest MSF. Soluble dietary fiber of hulless barley (7.84%) was increased after collet extrusion up to 0.34% and decreased after cooking extrusion up to 0.92%. Feed moisture content was the most influencing variable on L*, ΔE, MSF, and DG values of collet extrudates, whereas temperature was the most influencing variable on dietary fiber content.Practical applicationsThe results obtained are useful for the food industry for value addition of hulless barley by extrusion cooking. Parameters (feed moisture content, screw speed and temperature) and extrusion methods (collet or cooking extrusions) needed to produce extrudates with expected psychochemical properties can be predicted from this study.

Evaluation of Lallemantia royleana seed longevity under varying conditions of temperature and moisture content

Evaluation of Lallemantia royleana seed longevity under varying conditions of temperature and moisture content

Evaluating leachate recirculation with cellulase addition to enhance waste biostabilisation and landfill gas production

The effect of leachate recirculation with cellulase augmentation on municipal solid waste (MSW) biostabilisation and landfill gas production was investigated using batch bioreactors to determine the optimal conditions of moisture content, temperature and nutrients. Experimentation was thereafter scaled-up in 7L bioreactors. Three conditions were tested including (1) leachate recirculation only, (2) leachate recirculation with enzyme augmentation and (3) no leachate recirculation (control). Cumulative biogas production of the batch tests indicated that there was little difference between the leachate and control test conditions, producing on average 0.043m3biogaskg−1 waste. However the addition of cellulase at 15×106Utonne−1 waste doubled the biogas production (0.074m3biogaskg−1 waste). Similar trend was observed with the bioreactors. Cellulase addition also resulted in the highest COD reduction in both the waste and the leachate samples (47% and 42% COD reduction, respectively). In both cases, the quantity of biogas produced was closer to the lower value of theoretical and data-based biogas prediction indicators (0.05–0.4m3biogaskg−1 waste). This was likely due to a high concentration of heavy metals present in the leachate, in particular Cr and Mn, which are known to be toxic to methanogens.The cost-benefit analysis (CBA) based on the settings of the study (cellulase concentration of 15×106Utonne−1 waste) showed that leachate bioaugmentation using cellulase is economically viable, with a net benefit of approximately €12.1million on a 5Mt mixed waste landfill.

Stepwise drying of medicinal plants as alternative to reduce time and energy processing

The objective of drying medicinal plants is to extend the shelf life and conserving the fresh characteristics. This is achieved by reducing the water activity (aw) of the product to a value which will inhibit the growth and development of pathogenic and spoilage microorganisms, significantly reducing enzyme activity and the rate at which undesirable chemical reactions occur. The technical drying process requires an enormous amount of thermal and electrical energy. An improvement in the quality of the product to be dried and at the same time a decrease in the drying cost and time are achieved through the utilization of a controlled conventional drying method, which is based on a good utilization of the renewable energy or looking for other alternatives which achieve lower processing times without sacrificing the final product quality. In this work the method of stepwise drying of medicinal plants is presented as an alternative to the conventional drying that uses a constant temperature during the whole process. The objective of stepwise drying is the decrease of drying time and reduction in energy consumption. In this process, apart from observing the effects on decreases the effective drying process time and energy, the influence of the different combinations of drying phases on several characteristics of the product are considered. The tests were carried out with Melissa officinalis L. variety citronella, sowed in greenhouse. For the stepwise drying process different combinations of initial and final temperature, 40/50°C, are evaluated, with different transition points associated to different moisture contents (20, 30, 40% and 50%) of the product during the process. Final quality of dried foods is another important issue in food drying. Drying process has effect in quality attributes drying products. This study was determining the color changes and essential oil loses by reference the measurement of the color and essential oil content of the fresh product was used. Drying curves were obtained to observe the dynamics of the process for different combinations of temperature and points of change, corresponding to different conditions of moisture content of the product.

Relationship between resilient modulus and suction for compacted subgrade soils

The resilient modulus (MR) of pavement materials is a key parameter required in the mechanistic pavement design methods. Seasonal moisture regime and suction (s) fluctuations exert remarkable influence on the MR which should be measured or predicted to assist in the analysis of pavement distress and service life. This paper presents extensive experimental investigations to determine the MR-s relationship for three Canadian subgrade soils (a silty clay from Toronto, a marine clay from Ottawa and a glacial till from Indian Head) using two different experimental methods. Following the first method, glacial till specimens were consolidated to known stress and suction levels using the axis-translation technique before subjecting to cyclic loading tests to determine the MR. In the second method, equilibrium conditions were achieved with respect to different moisture contents for specimens of the silty clay and marine clay before cyclic loading tests. Suction was measured after the completion of cyclic loading tests using the filter paper method. Experimental results suggest varying degrees of non-linear relationships between the MR and the suction, gravimetric water content and external stress for different soils. A simple model, which is based on the soil-water characteristic curve and MR values at saturated and optimum moisture content conditions for prediction, is used to predict the measured MR-s relationship for the three soils. Same measurements were also predicted using two rigorous models from the literature that were proposed based on different approaches. It is shown that the simple model, compared with other two models, provides equally good predictions but requires remarkably less experimental data. The simple model therefore can be used in practice as a reliable tool for predicting the influence of suction and moisture content on the resilient modulus of subgrade soils.

Dynamic thermal response of building material layers in aspect of their moisture content

This paper investigates the impact of moisture content on the thermal inertia parameters of building material layers. Moisture variation affects the energy storage and therefore the energy gains/losses through buildings. To this effect the decrement factor and time lag are determined for three types of concrete layers and one of solid clay-bricks masonry layer. Their consideration is essential to enhance the design of building elements, from a thermal point of view, when exposed to varying moisture content conditions. Moisture content and relative humidity variations of each analysed layer, as defined by specific moisture storage functions, are shown to interrelate non-linearly with the layer resistor–capacitor circuit section parameters (thermal conductivity and volumetric heat capacity) showing notable consequences on the thermal inertia parameters. The dynamic thermal analysis is accomplished by using the thermal-circuit modelling approach and the nodal solution method. The deterioration of decrement factor and time lag due to moisture content are illustrated by appropriate metrics. Computer results for the studied layers with thicknesses varying from 10cm to 50cm show the influence of the variation of relative humidity and thickness on the decrement factor and time lag.

Model Dinamik Vigor Daya Simpan Benih Kedelai pada Penyimpanan Terbuka

<p>Soybean seed viability declines during seed storage. Soybean seed deteriorates rapidly, affected by its high protein content and often high humidity in the tropical environment. This research was aimed to develop dynamic model of soybean seed viability in an open storage. The study was conducted in three stages, namely: 1) desk study, 2) seed storage experiment, 3) development of seed storage model, simulation and verification of the model. The second stage of the experiment consisted of soybean seed storing and germination testing using completely randomized design. Treatments were three initial moisture content (7-8%, 9-10% and 11-12%) and four varieties of soybean (Anjasmoro, Wilis, Detam-1 and Detam-2). The results showed that the seed behaviour during storage period were affected by initial seed moisture content, initial viability, varieties and environmental condition. Therefore, seed moisture content, initial viability and varieties may be used as input model. Moisture content, integreting seed respiration, electric conductivity and seed storability vigor (VDSDB) were as model output. Simulation of Seed Storability Vigor Prediction Model with Model Construction Layer-Stella (MCLS) using relative humidity (RH), temperature, seed permeability, initial moisture content and initial viability as input model could logically predict the seed moisture content and seed storability vigor (VDSDB).</p>

Parametric Study of Hydroforming of Paper Materials Using the Explicit Finite Element Method with a Moisture‐dependent and Temperature‐dependent Constitutive Model

A moisture‐dependent and temperature‐dependent constitutive model for paper materials was proposed and implemented into a finite element model of the paper hydroforming process. Experimental hydroforming was conducted at temperatures of 23°C and 110 °C and moisture contents of 6.9 and 10.6 (respectively corresponding to 50 and 80% relative humidity). The proposed model, which also included the effects of drying, captured the extent of forming of all experimental results within reasonable accuracy. For the moisture content and temperature conditions in this study, the phenomenon of drying was found to be the reason why the application of temperature had a much greater effect on the degree of forming than hydroforming at various moisture contents. A simulation‐based parametric study was conducted in order to identify the importance of various process and material parameters. This parametric study confirmed many previous empirical findings and was capable of quantifying the extent to which these process and material parameters affect the three‐dimensional formability of paper. The coefficient of friction was identified as one of the most important factors when determining the extent of forming. Copyright © 2016 John Wiley & Sons, Ltd.

Propagation probability and spread rates of self-sustained smouldering fires under controlled moisture content and bulk density conditions

The consumption of large areas of peat during wildfires is due to self-sustained smouldering fronts that can remain active for weeks. We studied the effect of peat moisture content and bulk density on the horizontal propagation of smouldering fire in laboratory-scale experiments. We used milled peat with moisture contents between 25 and 250% (mass of water per mass of dry peat) and bulk densities between 50 and 150 kg m–3. An infrared camera monitored ignition, spread and extinction of each smouldering combustion front. Peats with a bulk density below 75 kg m–3 and a moisture content below 150% self-sustained smouldering propagation for more than 12 cm. Peat with a bulk density of 150 kg m–3 could self-sustain smouldering propagation up to a critical moisture content of 115%. A linear model estimated that increasing both moisture content and bulk density significantly reduced the median fire spread rate (which ranged between 1 and 5 cm h–1). Moisture content had a stronger effect size on the spread rate than bulk density. However, the effect of bulk density on spread rate depends upon the moisture content, with the largest effect of bulk density at low moisture contents.

Experimental and statistical evaluation of compressibility of fresh and landfilled municipal solid waste under elevated moisture contents

An investigation of the variability associated with primary and secondary compression indices of municipal solid waste (MSW) is conducted in the present study. A controlled laboratory experimental program was conducted to quantify the compressibility of fresh MSW and landfilled MSW (subjected to leachate recirculation for a year in the field) under different elevated moisture content conditions. Several series of one-dimensional compressibility experiments were conducted on fresh and landfilled waste samples under the field moisture content of 44% (by dry weight) and three elevated moisture contents of 60, 80 and 100% (by dry weight). The compression of waste samples was measured at different elapsed time periods under incremental normal stresses of 48, 96, 192, 383, and 766 kPa. The modified compression indices (or compression ratios) were calculated based on the measured compression versus stress data. Long term secondary compression behavior was determined by performing long term compression tests on fresh and landfilled waste samples under normal stress of 383 kPa. The steep slope is not evident on the vertical stress – strain plot for the 44% moisture content sample, potentially owing to breakdown of micro-fabric and mini-fabric of fresh waste and rearrangement of the particles. It is observed from the present study that the magnitudes of modified primary compression index for fresh MSW exhibited no specific correlation with an increase in moisture content from 44 to 100% owing to variations in the initial composition of fresh MSW, small scale laboratory testing, and rate of biodegradation of MSW. For a constant vertical stress, the landfilled waste compressed less than the fresh waste at initial and elevated sample moisture contents owing to reduction of organic content in the degraded waste. Based on the compilation of compression indices from several published studies, the average values of mean, standard deviation and coefficient of variation for modified primary compression and secondary compression indices are computed. Overall, this study demonstrated that the long term compression characteristics can highly vary depending on the waste composition, moisture content, and biodegradation. From the statistical analysis, it is determined that the variability associated with secondary compression index is significantly higher than the primary compression index , which may be attributed to significant differences in the biodegradable content of waste and associated extent and rate of biodegradation of waste.

Remediation of DDT and Its Metabolites in Contaminated Sediment

Chlorinated pesticides and chlorinated organics can be transformed or partially degraded in sediments under appropriate environmental conditions. Although 1,1,1-trichloro-2,2-bis[p-chlorophenyl]ethane (DDT) is very persistent in the environment, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), a degradation product of DDT, is generally the constituent most widely detected in the environment and DDE is also resistant to further biotransformation. DDT and its degradation products (DDTR) may be transported from one medium to another by sorption, bioaccumulation, dissolution, or volatilization. In sediments, DDT strongly adheres to suspended particles, but once metabolized, DDE, the primary product, is slightly soluble in water. The major migration process for DDTR in sediment-water systems is sorption to sediment or other organic matter and the primary distribution route is the transportation of the particulates to which the compound is bound. Understanding the fate and transport of DDTR in the natural environment based on its specific characteristics is important in determining appropriate remediation option. Common DDT-contaminated sediment remediation options include dredging, capping, and natural attenuation. Sediment washing and phytoremediation have also been used in contaminated sites. Dredging is the most common sediment remediation option to remove the contaminated benthic sediments but often suffers from technical limitations like incomplete removal, unfavorable site conditions, sediment resuspension, and disposal issues. Capping is an in situ, low-cost remediation option for immobilization of DDT in several contaminated sediment sites. Natural or anthropogenic materials containing reactive ingredients, as distinct from a conventional sand or gravel cap, involve placing reactive materials as part of the cap matrix to increase sorption, and to enhance chemical reactivity with DDTR, or accelerate degradation. Natural attenuation can treat the DDT-contaminated sediment, but the time frame for complete remediation may be relatively long. Addition of suitable co-metabolites and acclimatized microorganisms to DDTR-contaminated sediment and alteration of sediment-water micro-environment by manipulating soil pH, moisture content, and other chemical conditions may result in degradation of DDTR associated with sediments at rates faster than the natural attenuation rate.

Thermal performance improvement of a horizontal ground-coupled heat exchanger by rainwater harvest

Increased moisture content leads to increased thermal conductivity and is beneficial for heat exchange of ground-coupled heat exchangers (GCHE). In this study, a horizontal GCHE was combined with a rain garden, characterized by the beneficial supply of rainwater to groundwater, increased soil moisture content and favorable conditions for GCHE. Sandy soil container experiment results showed that water immigration was possible under thermal action of the horizontal GCHE. Compared with little water transfer under the heat evacuation condition, with a relatively small temperature difference between fluid and adjacent soils, heat and water transfer were coupled under the heat rejection condition and a drying region appeared at regions adjacent to the tube wall because of the relatively large temperature difference. Water immigration was more likely to occur when sandy soil had low moisture content, for example 0.1 m3/m3. The coupled heat and water transfer model was necessary for prediction of horizontal GCHE thermal performance. Under high moisture content conditions, the coupled model was dispensable but it was necessary to consider moisture-dependent variation in thermal conductivity.

Model for predicting resilient modulus of unsaturated subgrade soil using soil-water characteristic curve

Soil suction (ψ) is one of the key factors that influence the resilient modulus (MR) of pavement subgrade soils. There are several models available in the literature for predicting the MR–ψ correlations. However, the various model parameters required in the existing models are generally determined by performing regression analysis on extensive experimental data of the MR–ψ relationships, which are cumbersome, expensive, and time-consuming to obtain. In this paper, a model is proposed to predict the variation of the MR with respect to the ψ for compacted fine-grained subgrade soils. The information of (i) the MR values at optimum moisture content condition (MROPT) and saturation condition (MRSAT), which are typically determined for use in pavement design practice; (ii) the ψ values at optimum moisture content condition (ψOPT); and (iii) the soil-water characteristic curve (SWCC) is required for using this model. The proposed model is validated by providing comparisons between the measured and predicted MR–ψ relationships for 11 different compacted fine-grained subgrade soils that were tested following various protocols (a total of 16 sets of data, including 210 testing results). The proposed model was found to be suitable for predicting the variation of the MR with respect to the ψ for all the subgrade soils using a single-valued model parameter ξ, which was found to be equal to 2.0. The proposed model is promising for use in practice, as it only requires conventional soil properties and alleviates the need for experimental determination of the MR–ψ relationships.

Environmental and Geotechnical Assessment of the Steel Slags as a Material for Road Structure

Slags are the final solid wastes from the steel industry. Their production from waste and associated materials is a proper implementation of the basic objectives and principles of the waste management. This study aims to investigate the chemical and selected significant geotechnical parameters of steel slag as the alternative materials used in road construction. These investigations are strongly desired for successful application in engineering. Young’s modules E, and resilient modules Mr showed that their values corresponding with requirements for subbase (principal or auxiliary) and riding surface as well. Tested mechanical properties were conducted in soaked and un-soaked (optimal moisture content) conditions. The designated high content of chromium and zinc are strongly associated with the internal crystal structure of steel slag. The results do not lead to threats when they are applied in roads’ structures. Mechanical characterization was obtained by performing California bearing ratio (CBR) tests for steel slag in fixed compaction and moisture content conditions. Moreover, cyclic loading of steel slag was conducted with the application of cyclic California bearing ratio (cCBR) apparatus to characterization of this material as a controlled low-strength material. Finally, field studies that consist of static load plate VSS tests were presented.

Sioen buys Le Comptoir Zouloo

Cryptobiotic soil crusts form the dominant cover of a unique system of dunes and intermittently inundated pans and playas situated on the Pleistocene Lake Thompson bed, in the western Mojave Desert, CA. Recent work has reported on basic ecological parameters including distribution, abundance, and species composition of these algal (cyanobacterial)-dominated crusts as well as on their photosynthetic rates in laboratory studies. As a step toward building an ecological model for a natural resource management plan, we determined the photosynthetic rate of the crusts under field environmental conditions. We examined the relationship between the environmental conditions of crust moisture content (MC), temperature, and ambient CO2 concentration on photosynthetic rates during the mid-spring and the late autumn.Maximal photosynthetic rates (Pmax), which did not vary greatly with season, were 3.57 and 3.99 μmol CO2 m−2 s−1 for crusts on dunes and in pans, respectively. Mean photosynthetic rates for three types of crust on dunes, smooth and flat, pedicillated, and unconsolidated, were 1.31, 1.47, and 1.29 μmol CO2 m−2 s−1, respectively. Pmax of crusts on dunes and pans occurred at soil MCs of 110% and 20%, respectively, both lower and higher MCs resulted in decreased rates of photosynthesis. The relation between atmospheric CO2 concentration and net photosynthesis was linear (r2=0.88 and 0.97 for crusts on dunes and pans, respectively) through at least 1000 ppm CO2. We measured positive net photosynthesis at temperatures from 0 to 46 °C and found no clear optimum within this range when crusts were provided with optimal moisture and light conditions. Photosynthetic rates in this field study were somewhat lower than those measured in the laboratory, but both optimum MC and the relation between ambient CO2 and net photosynthetic rate were similar. Respiration rates were generally less than 10% those of photosynthetic rates. Based on data herein and climatic information, we estimated the potential net primary productivity of crusts on dunes to be 11.7 g C m−2 yr−1. The photosynthetic rate of the unconsolidated crust type, for which no data have been published, was similar to the other crust types. This finding, together with previous information that the chlorophyll values of this and other crust forms were similar, suggests that ecological studies, as well as conservation and restoration efforts, give these the same attention as the other crust types.

Huber acquires Safire flame retardants technology from Floridienne/Catena

Cryptobiotic soil crusts form the dominant cover of a unique system of dunes and intermittently inundated pans and playas situated on the Pleistocene Lake Thompson bed, in the western Mojave Desert, CA. Recent work has reported on basic ecological parameters including distribution, abundance, and species composition of these algal (cyanobacterial)-dominated crusts as well as on their photosynthetic rates in laboratory studies. As a step toward building an ecological model for a natural resource management plan, we determined the photosynthetic rate of the crusts under field environmental conditions. We examined the relationship between the environmental conditions of crust moisture content (MC), temperature, and ambient CO2 concentration on photosynthetic rates during the mid-spring and the late autumn.Maximal photosynthetic rates (Pmax), which did not vary greatly with season, were 3.57 and 3.99 μmol CO2 m−2 s−1 for crusts on dunes and in pans, respectively. Mean photosynthetic rates for three types of crust on dunes, smooth and flat, pedicillated, and unconsolidated, were 1.31, 1.47, and 1.29 μmol CO2 m−2 s−1, respectively. Pmax of crusts on dunes and pans occurred at soil MCs of 110% and 20%, respectively, both lower and higher MCs resulted in decreased rates of photosynthesis. The relation between atmospheric CO2 concentration and net photosynthesis was linear (r2=0.88 and 0.97 for crusts on dunes and pans, respectively) through at least 1000 ppm CO2. We measured positive net photosynthesis at temperatures from 0 to 46 °C and found no clear optimum within this range when crusts were provided with optimal moisture and light conditions. Photosynthetic rates in this field study were somewhat lower than those measured in the laboratory, but both optimum MC and the relation between ambient CO2 and net photosynthetic rate were similar. Respiration rates were generally less than 10% those of photosynthetic rates. Based on data herein and climatic information, we estimated the potential net primary productivity of crusts on dunes to be 11.7 g C m−2 yr−1. The photosynthetic rate of the unconsolidated crust type, for which no data have been published, was similar to the other crust types. This finding, together with previous information that the chlorophyll values of this and other crust forms were similar, suggests that ecological studies, as well as conservation and restoration efforts, give these the same attention as the other crust types.

Modeling conventional drying of wood: Inclusion of a moving evaporation interface

ABSTRACTA one-dimensional mathematical model is presented that accounts for a moving evaporation interface in simulating the coupled heat and mass transfer during convective drying of wood. In the model proposed, the only mechanism considered in water transport within wood is diffusion. Additionally, the transport of moisture is dominated by the gradient of the moisture content. The controlling equations were established from Whitaker’s volume averaging laws and solved numerically with the finite volume method. The simulation results for the density of vapor and the volume rate of evaporation indicate that the migrating moisture was mainly in the form of gas under conditions of lower moisture content. The evaporation interface moved at approximately constant speed and the evaporation rate of the interface decreased with time. Finally, the core temperature and average moisture content in wood were successfully simulated.

Stress–Strain Response of Unbound Granular Materials Under Static and Cyclic Loading

Resilient modulus is an important parameter in flexible pavement engineering design. The stress–strain behavior of unbound granular base materials under static and cyclic loading and the effects of the state of stress, moisture content and loading conditions have been analyzed in the present study. In this paper, the resilient behavior of unbound granular materials and the applicability of different constitutive models are examined in order to understand the behavior of granular material under static and cyclic loading. Since the aggregate material exhibits a complex stress–strain behavior, more than one model will be required to predict the stress–strain response of granular materials. Hence, different constitutive models have been considered in the present study which can adequately predict the stress–strain response of aggregate materials. Considering the constitutive models used in the present study, it could be said that the Lentz and Baladi model and the normalized degradation model suitably bring out a relation between static and cyclic tests. This is a useful input in pavement design and explains the variation of modulus with load repetitions.