Increase In Equilibrium Moisture Content Research Articles

Moisture adsorption isotherms properties of dried overripe barlin fruit (Musa acuminata AA.) powder

Moisture sorption of dried overripe barlin banana powder using the static gravimetric method. The materials were conditioned at 5, 10, and 25 oC with a water activity range of 0.16 to 0.86. Five mathematical models to describe the suitability of the phenomenon of adsorption experimental data using non-linear regression. The thermodynamic properties such as isosteric heat and Gibbs free energy are evaluated in this paper. The experimental results indicated that the equilibrium moisture content of dried overripe barlin banana powder increased with increasing water activity and decreasing temperature. The results of the model are based on the goodness of fit, and the Peleg model is the most suitable for describing the adsorption phenomenon with the type II sigmoidal shape. Monolayer moisture content and adsorption surface area using the GAB model are in the range of 6.18-7.81%d.b and 219.09-246.39 m2/g d.b, respectively, which increases with increasing temperature. Moreover, isosteric heat decreases with an increase in equilibrium moisture content and is opposite to the value of Gibbs free energy. In addition, the hygroscopicity of the dried overripe barlin banana powder increased with temperature and water activity.

Moisture sorption isotherms and thermodynamic properties of tiger nuts: An oil-rich tuber

The moisture adsorption isotherms of tiger nuts were determined by a gravimetric static method at 15, 25, 35 °C within the water activity varying from 0.113 to 0.979. Ten mathematical models were selected to fit the adsorption data using non-linear regression technique. Thermodynamic properties such as isosteric heat, sorption entropy and Gibbs free energy were evaluated. The results indicated that equilibrium moisture content of tiger nuts tended to increase with increasing water activity and decreasing temperature. The isotherm curves of tiger nuts exhibited a Type Ⅱ sigmoidal shape. Peleg model was the most suitable for describing the experimental sorption behavior, followed by the Smith and GAB models. The adsorption surface area and monolayer moisture content of tiger nuts obtained from GAB model were 166.37–149.74 m2/g solid and 4.71–4.24 H2O/100 g solid, respectively, which decreased with increasing temperature. Moreover, the isosteric heat of adsorption decreased exponentially with the increase of equilibrium moisture content, while the Gibbs free energy was opposite. Adsorption entropy was negative in value and it decreased sharply and then rose slowly as the moisture content increased, having a minimum value (6.43 J/mol K) at a moisture content of 11 g/100 g d.b.

Effect of Acetylation and Accelerated Weathering of Nigerian Grown Rubberwood (Hevea brasiliensis, Müll. Arg.) on Equilibrium Moisture Content and Colour Change

This study was conducted to investigate the effect of acetylation on equilibrium moisture content (EMC) of Nigerian-grown rubberwood and its effect on colour change in exposure of rubberwood to surface degradation through accelerated weathering. The samples were modified to two levels of acetylation, which yielded weight percent gain (WPG) of 7 % and 10 % after 8hr (8-hr Acetyl) and 48hr of acetylation (48-hr Acetyl), respectively. Accelerated weathering of unmodified (Ref) and acetylated wood was done using QUV-Accelerated Weathering Tester for four weeks. The unmodified and acetylated samples (weathered and unweathered) were oven-dried and conditioned in climate rooms at different relative humidity of 50 %, 65 % and 95 %, with samples being moved to each room after 14 days. Results showed that acetylation led to a significant decrease in equilibrium moisture content of rubberwood. After weathering, there was a decrease in EMC of rubberwood due to removal of hemicelluloses alongside the degraded lignin, and a slight increase in EMC of the acetylated wood. In terms of colour change, photo-bleaching of the acetylated samples was higher (10.46 for 48-hr Acetyl) after four weeks of weathering compared to the unmodified samples (6.43). Hence, the outcome of this study has shown that, although acetylation is effective in minimizing moisture ingress into wood, it resulted in photo-bleaching of the weathered samples. Additional surface coating is recommended to serve as a protective layer, preventing partial washing out of the acetyl groups, minimize photo-bleaching during weathering and prolong the aesthetic value of the wood especially in outdoor applications such as wall cladding and façade.

Moisture sorption properties of two varieties of dehydrated mango slices as determined by gravimetric method using Guggenheim–Anderson–de Boer model

The moisture sorption isotherms for oven dried mango were constructed gravimetrically at three different temperatures of 25°C, 30°C, and 35°C, and relative humidity ranging 8.3%–97.0%. The Guggenheim–Anderson–de Boer model was used to fit sorption data and constant equations determined using nonlinear regression analysis. The isotherms had J-shaped curve that represents type III isotherms characterized by sugar-rich products. At increased temperatures, it was observed that equilibrium moisture content increased and crossing effect of isotherm curves was observed with a corresponding increase in water activity. A substantial increase in equilibrium moisture content was observed above water activity of 0.6. Monolayer moisture content of between 8 and 9.6% was predicted for dried slices where the lowest value indicated that moisture content should not be lower than 8.0% to avoid unnecessary energy consumption. For assured microbiological stability, the safe storage moisture content for dried mango should be maintained at approximately 15% or less that corresponded to 0.6 water activity. Practical applications Dehydration of fruits has been utilized as one of the most effective value addition procedures for extending their shelf-life. However, exposure to high drying temperature and significant loss of moisture in fruits cause irreversible stresses in the cellular structure of the fruits and may lead to robust textural changes especially during storage. This research finds practical application in shelf-life estimation and prediction of storage stability of the mango varieties. Additionally, the results can be used as a guide in product development and process design for dried mango slices.

Durability of Wood Exposed to Alternating Climate Test and Natural Weathering

The use of wood-based materials in the automotive industry is currently under discussion and investigation. One of the major material requirements for such applications is sufficient weathering stability. This can be demonstrated by an accelerated aging process in which the samples are exposed to changing climatic conditions and a spray mist of an aqueous NaCl solution. The effects of media salt (NaCl) on the mechanical and physical properties of wood have scarcely been investigated. The presented study investigated the changes in bending strength (MOR), modulus of elasticity (MOE), and impact bending strength (α) of naturally and artificially weathered oak (Quercus spp.) and birch (Betula pendula Roth) wood. The tests provided comparable results. The decrease under natural weathering of oak was 3.73%, 4.69%, and 6.45% for MOR, MOE, and α. Under artificial weathering the decrease observed for oak was 7.33%, 10.87%, and 16.29% and 3.2%, 8.21%, and 4.03% for birch respectively. It is remarkable that α increased for birch wood at the beginning of the artificial weathering cycles. The penetration of the aqueous NaCl solution into the wood substance resulted in an increase in the wood’s equilibrium moisture content (EMC), which can be explained by the stronger hygroscopic properties of NaCl compared to wood. The higher impact strength at the beginning of artificial weathering can be partly explained by this increase in EMC. In order to investigate the penetration behavior of salt into the wood substrate, the artificially weathered samples were examined by means of energy dispersive X-ray analysis (EDX) and it was shown that the salt concentration changes significantly over the weathering cycles and sample cross-section.

Water sorption hysteresis in wood near 100 °C

Abstract Whether water sorption hysteresis exists above 75 °C and the representation of its relationship with wood softening remains unclear. In this study, sorption hysteresis at three temperature levels, namely, 75, 90 and 99.5 °C, was investigated using accurately controlled conditioning chambers using powder samples from seven wood species. The dry mass loss percentage of the samples and proper equilibrium time was evaluated by pretests to ensure reliable sorption isotherms afterwards. The dry mass loss percentage after the entire sorption isotherm running needs to be kept within 0.5% to avoid complications in determining the equilibrium time. The abrupt increase of equilibrium moisture content at high relative humidity regions and the crossover of adsorption isotherms were not observed. Hysteresis was conspicuous at 75 and 90 °C and was statistically confirmed at 99.5 °C. High sample extractives content or unnecessarily long equilibrium time would cause significant sample dry mass loss, which may suppress the desorption isotherm to an extent that leads to unjustified hysteresis disappearance. The hysteresis behavior observed in this study suggests that wood softening does not necessarily result in hysteresis disappearance, and the explanation of hysteresis progression as a function of wood softening temperature must be evaluated with care in the future.

Water sorption isotherms of cooked hams as affected by temperature and chemical composition

Abstract This study was focused on the determination of the chemical composition and experimentally obtaining the sorption isotherms for four samples of commercial cooked ham subjected to simulated commercial storage conditions. The isotherms were determined using the gravimetric method. The mathematical models of Guggenhein, Anderson and de Boer; Brunauer, Emmett and Teller; Halsey; Henderson; and Peleg were fitted to the experimental data. The Guggenhein, Anderson and de Boer model was chosen to best describe the isotherms as it had a very good fit. The increase in temperature reduced the equilibrium moisture content of the product. Increased relative humidity resulted in an increase in equilibrium moisture content of the product regardless of storage temperature. The differences in chemical composition between the samples affect the desorption isotherms. The higher the content and availability of the protein or the lower the fat content, the higher the equilibrium moisture content of the product.

Determination and modeling of the isotherms of adsorption/desorption and thermodynamic properties of obeche and lotofa using nelson’s sorption model

Equilibrium moisture content (EMC), net isosteric heat of sorption (NIHS), net entropy of sorption (NES) and standard free energy of Gibbs (SFEG) of Triplochiton scleroxylon (obeche) and Sterculia rhinopetala (lotofa) are modeled using Nelson’s sorption isotherm model. Experimental data are determined using a dynamic vapor sorption apparatus. Air relative humidity is ranged from 0 to 90% and two air temperatures (20 °C and 40 °C) are used. Experimental data of EMCs obtained from adsorption and desorption for the mentioned woods were compared with the predicted results using Nelson’s sorption model by the application of the same operating conditions (i.e. temperatures and relative humidity conditions). The results showed that the predicted ones were in good agreement with the experimental data, when the relative humidity varied from 1.2 to 90%. Both adsorption and desorption phase presented a mean relative errors value inferior to 6.3%. The parameters that define the sorption isotherm varied with the wood type and the sorption mode. Thus, Nelson’s sorption isotherm model is a useful tool that can be used for prediction of the moisture change in wood under different environmental conditions and for predicting indirectly the thermodynamic parameters such as NIHS, NES and SFEG. In adsorption and desorption mode, the NIHS are estimated using Clausius-Clapeyron’s equation. The desorption values were higher than the adsorption ones. NIHS versus EMC varied exponentially and the parameters of the function were presented variable with the sorption mode and the wood type. The total energy that we needed to extract and evaporate all bounded water is 12,398.6 J/mol for obeche and 11,627.7J/mol for lotofa. The total energy that we needed to condense and fix all bounded water taken from the state vapour is 11,829.34 J/mol for obeche and 11,379.39 J/mol for lotofa. Water molecules are more mobile during desorption than adsorption in the case of obeche. In the case of lotofa, these molecules are more mobile during adsorption. SFEG is higher in desorption than adsorption and it is influenced by species and less by the temperature. When the temperature increased, the SFEG increased as well. At low values of EMC, NIHS and SFEG are higher and decreased with the increase of EMC until reaching the fibre saturation point.

MOISTURE SORPTION ISOTHERMS OF QUINOA SEEDS: THERMODYNAMIC ANALYSIS

The present work aimed to study the water sorption behavior of quinoa seeds analyzing the hysteresis phenomenon and determining thermodynamic properties. Static gravimetric technique was used to obtain the equilibrium moisture content of quinoa seeds in different temperature conditions (15, 25, 35 e 50 °C) and relative humidity (between 11 and 96%). Equilibrium moisture content data were adjusted by eight mathematical models and the Modified Halsey model was the best one to describe the water sorption phenomena of quinoa seeds. Hygroscopic equilibrium moisture content of quinoa seeds is directly proportional to the water activity and decreases with increasing temperature. The hysteresis phenomena were observed throughout the range of water activity, showing more evident at low temperatures. Integral isosteric heat and differential entropy decreased with the increase of equilibrium moisture content. Gibbs free energy decreased with the increase of temperature and equilibrium moisture content. Compensation enthalpy-entropy theory was confirmed and the sorption mechanism is controlled by enthalpy.

Experimental study of hygroscopic equilibrium and thermodynamic properties of sewage sludge

A good knowledge of the hygroscopic behavior of sewage sludge is one of the keys to a better perception of the subsequent management of Sewage sludge such as drying, storage or other valorization processes. The present work aims to determine, experimentally, the sorption isotherms of sewage sludge generated at the wastewater treatment plant of Marrakesh city in Morocco by using saturated salt solutions method at different temperatures.The obtained results show that, at constant water activity, the increase in temperature leads to a decrease of the sorption curves. Seven statistical models have been used for modeling and analyzing the experimental data of sorption. The Peleg model seems to be the most appropriate to describe the desorption and adsorption isotherm curves of sewage sludge with the highest value of correlation coefficient.Thermodynamic properties of sewage sludge were determined by using the hygroscopic equilibrium data at different temperatures, the net isosteric heat of sorption and entropy of sorption decreased considerably with the increase in equilibrium moisture content. The enthalpy–entropy compensation suggested that the sorption mechanism involved was enthalpy given. Gibbs free energy for adsorption and desorption are respectively 58.87 kJ/mol, and -445.21 kJ/mol, indicating two different processes.

Sorption isotherms of waterlogged subfossil Scots pine wood impregnated with a lactitol and trehalose mixture

AbstractA waterlogged subfossil Scots pine wood, 12 500-years-old, was impregnated with a mixture of lactitol and trehalose as well as with polyethylene glycol (PEG) mixtures, respectively, and the sorption properties of the impregnated samples were determined. All the impregnated wood samples were freeze-dried. The sorption isotherms were parameterized with the Guggenheim-Anderson-deBoer (GAB) and Generalized D’Arcy and Watt (GDW) models. Better hygroscopic properties were found for wood impregnated with the lactitol and trehalose mixture as compared to the PEG treatments. An anomalous increase of equilibrium moisture content (EMC) was found for PEG treated wood at a high relative humidity (RH) as compared to untreated wood at RH<80%. The lactitol and trehalose mixture significantly reduced this effect due to the decreased sorption of polymolecular water. Another positive effect of the alternative method is the ca. 50% reduction of the sorption hysteresis as compared to untreated wood. Moreover, the hysteresis was also much lower in the case of high RH as compared to PEG treated wood. The alternative treatment is also effective in terms of the dimensional stabilization of decayed wood.

<b>Kinetic modeling of water sorption by roasted and ground coffee

The objective of this study was to model the kinetics of water sorption in roasted and ground coffee. Crude Arabica coffee beans with an initial moisture content of 0.1234 kg w kg dm -1 were used. These beans were roasted to a medium roast level (SCCA # 55) and ground at three particle sizes: coarse (1.19 mm), medium (0.84 mm) and fine (0.59 mm). To obtain the water sorption isotherms and the isosteric heat, different conditions of temperature and relative humidity were analyzed using the dynamic method at 25oC (0.50, 0.60, 0.70, and 0.80 of RH) and 30°C (0.30, 0.40, 0.50, 0.60, 0.70, and 0.80 of RH) and using the static method at 25oC (0.332 and 0.438 of RH). The GAB model best represented the hygroscopic equilibrium of roasted coffee at every particle size. Isosteric heat of sorption for the fine particle size increased with increments of equilibrium moisture content, indicating a strong bond energy between water molecules and the product components. The Gibbs free energy decreased with the increase in equilibrium moisture content and with temperature.

Moisture Sorption Isotherm of Underutilized Culinary Banana Flour and Its Antioxidant Stability during Storage

The moisture sorption isotherm of vacuum dried culinary banana flour was studied using standard static-gravimetric technique at five different temperatures (25–45C). There was a gradual increase in equilibrium moisture content (EMC) between 0.1 and 0.65 water activities (aw), and EMC increased beyond 0.65 aw led to type II isotherm of sigmoidal characteristics. The effect of temperature on EMC was not significant at P > 0.05. Among the seven models fitted, Peleg model showed the highest coefficient of determination (R2) with lower values of relative deviations (Rd < 10%) and fulfilled the necessary criteria desired for the model and best fitted. The net isosteric heat of sorption (qst) determined from the equilibrium sorption data using Clausius–Clapeyron equation showed the decreasing trend of qst with increasing EMC. Additionally, the antioxidant and polyphenols stability of culinary banana flour monitored at 25C showed minor degradation up to 120 days without affecting its bioactive properties. Practical Applications The nutritionally rich culinary banana (kachkal) of Assam, India having immense regional importance is yet to gain much attention and fall under the category of underutilized crop. We focused to utilize this underutilized crop for the benefit of society in terms of nutrients, functionality and healthy diet. The sorption isotherms of culinary banana flour obtained in the present study could provide essential information on designing, optimization and prediction of drying processes, storage conditions and selecting appropriate packaging materials. This study will be useful for low moisture food industry where culinary banana could promote as high value-added flour.

Effects of plasticizers on sorption and optical properties of gum cordia based edible film.

The present study aimed to characterize a biodegradable film produced from the polysaccharide of an indigenous plant Cordia myxa. Effect of plasticizer type (Glycerol, Sorbitol, PEG200 and PEG 400) and concentration (0-30%) was studied on sorption and optical properties of the casted film. Increase in plasticizer concentration resulted in increase in equilibrium moisture content of the film and was supported by GAB model of sorption indicating that isotherms were of Type II. The monolayer value increased with the increase in plasticizer concentration with a peak of 0.93g.g-1 for glycerol. Addition of plasticizers improved the total color (ΔE) with glycerol showing the highest effects. All films showed resistance to UV light in the range of 280-200nm. The polysaccharide of the fruit of C.myxa can be used to prepare an edible film with improved properties as compared to other available edible coatings.

Influence of Density and Equilibrium Moisture Content on the Hardness Anisotropy of Wood

Abstract The aim of this study was to investigate the anisotropic characteristics of Brinell hardness for six species (softwood, Chinese fir [Cunninghamia lanceolata (Lamb.) Hook.], Red pine [Pinus koraiensis Sieb. et Zucc.], Mongolian scotch pine [Pinus sylvestris L. var. mongolica Litv.]; hardwood, Manchurian walnut [Juglans mandshurica Maxim.], Asian white birch [Betula platyphylla Suk.], Mongolian oak [Quercus mongolica Fisch. et Turcz.]) with the equilibrium moisture content (EMC) obtained at four relative humidity (RH) levels (20°C; 50%, 65%, 85%, and 95% RH). The results showed that the cross section of specimens presented higher Brinell hardness and lower elastic recovery than those tested on radial and tangential surfaces. Ovendried density was significantly positively correlated with Brinell hardness. With the exception of softwood on a tangential surface (r = 0.02), there was a statistically significant positive correlation of elastic recovery against ovendried density (at the 0.01 level). We found that a general increase in EMC significantly lowered the Brinell hardness for six species, irrespective of grain orientation. The decreased extent of relative Brinell hardness (HB/HB0) was highest for cross section samples, compared with radial and tangential surfaces. For three softwood species, the decreased extent of HB/HB0 on the radial surface was higher than that on the tangential surface, whereas the opposite relationship was found in three hardwood species. The results indicated that rays were probably the main factor controlling transverse anisotropy in hardwood, while the interaction of earlywood and latewood was more important for softwood. In addition, elastic recovery anisotropy was probably owing to different failure behavior in three directions, and it was difficult to establish a direct influence of EMC on elastic recovery.

Moisture Sorption and Thermodynamic Properties of Vacuum-Dried Capsosiphon fulvescens Powder.

The moisture sorption isotherms of vacuum-dried edible green alga (Capsosiphon fulvescens) powders were determined at 25, 35, and 45°C and water activity (a w) in the range of 0.11~0.94. An inversion effect of temperature was found at high water activity (>0.75). Various mathematical models were fitted to the experimental data, and Brunauer, Emmett, and Teller model was found to be the most suitable model describing the relationship between equilibrium moisture content and water activity (<0.45). Henderson model could also provide excellent agreement between the experimental and predicted values despite of the intersection point. Net isosteric heat of adsorption decreased from 15.77 to 9.08 kJ/mol with an increase in equilibrium moisture content from 0.055 to 0.090 kg H2O/kg solids. The isokinetic temperature (T β) was 434.79 K, at which all the adsorption reactions took place at the same rate. The enthalpy-entropy compensation suggested that the mechanism of the adsorption process was shown to be enthalpy-driven.

Moisture sorption isotherms and thermodynamic properties of whole black peppercorns (Piper nigrum L.)

Adsorption and desorption isotherms for whole black peppercorns (Piper nigrum L.) were developed at 22, 30 and 37 °C using standard static gravimetric method. The sorption isotherms exhibited a type III behaviour according to Brunauer-Emmett-Teller (BET) classifications. The equilibrium moisture content (EMC) decreased with increasing temperature at a particular water activity (aw). Hysteresis existed over the entire aw range at 30 and 37 °C. At 22 °C, an intersection of the curves was found at aw closer to 0.75. The goodness of fit of the models was evaluated using several statistical indices and residual plots. The Guggenheim-Anderson-de Boer (GAB) and Peleg models were determined to best describe the experimental sorption data. The monolayer moisture content (M0) were 4.78, 3.56 and 3.49 g/100 g at 22, 30 and 37 °C for adsorption. The maximum isosteric heat of sorption was 28.1 and 73.3 kJ/mol for adsorption and desorption, respectively. The net isosteric heat of sorption and sorption entropy increased with increase in EMC; both curves dropped off exponentially after M0. The Gibbs free energy change for adsorption ranged from 100.6 to 9370.6 J/mol. The black peppercorns can be stored at 22, 30 and 37 °C, by reducing their MC to 10, 8 and 7 g/100 g, respectively, with aw below 0.60.

Equilibrium moisture content (EMC) in Norway spruce during the first and second desorptions

Abstract It is a commonly accepted notion that the equilibrium moisture content (EMC) of wood at a given relative humidity (RH) is highest during initial desorption of green wood due to an irreversible loss of hygroscopicity during the 1st desorption. The basis for this notion is investigated by assessing how drying and saturation procedures influence the differences between the 1st and the 2nd desorption curves for Norway spruce (Picea abies (L.) Karst.) sapwood. The study establishes 1st and 2nd desorption isotherms for a variety of initial conditions and it covers the RH range from 60.1% to 99.9%. The state of the water is not affected by oven-drying and rewetting as demonstrated by time domain low field NMR relaxometry. The results challenge the conclusions of earlier studies and indicate that in these studies the 2nd desorption was initiated at much too low EMC and therefore fails to describe a boundary desorption isotherm. Instead, it becomes an intermediate desorption isotherm starting at the adsorption boundary curve and crossing over to eventually meet the desorption boundary curve. The results also show that vacuum drying at room temperature only gives a modest loss of hygroscopicity compared to the green state. Conversely, oven-drying at 103°C results in a more significant loss of hygroscopicity, except for RH above 96% where an increase in EMC surprisingly is seen.

Determinação da cinética e das isotermas de secagem do bagaço da laranja

Knowing the behavior of orange bagasse during drying is very important when using it for technological purposes, as is the case of its application as an adsorbent. This work had as objective the determination of the kinetics and isotherms of orange bagasse drying. In order to obtain the drying and drying rate curves, the bagasse was dried in a convective drier, at temperatures from 33 to 92&ordm;C, with constant air speed of 1.3 m s-1. The equilibrium isotherms were determined using the Thermoconstanter Novasina device, with temperatures between 25 and 45&ordm;C. The moisture of the bagasse on a dry basis (d.b.) was determined by the furnace method. The drying curves and drying rate curves showed that the increase in temperature decreased drying time, due to an increase in the drying rate. In equilibrium isotherms, the increase in temperature caused an increase in equilibrium moisture content, a factor attributed to the characteristic of the material. The experimental data were adjusted to the BET, SABBAH and OSWIN models; under the studied conditions, the SABBAH model presented the best adjustment, with a correlation coefficient of 0.99.

MOISTURE ADSORPTION THERMODYNAMICS OF FRACTIONATED SESAME HULLS (SESAMUM INDICUM L.)

ABSTRACT Sesame hulls are a useful byproduct of sesame processing industry. Moisture adsorption isotherms (MSIs) for whole sesame hulls (WSHs) and powdered sesame hulls (PSHs) were obtained at 15, 30 and 45C, and 0.05 to 1.5 moisture content (decimal dry basis) using a water activity meter. Four MSI models were tested. Halsey model was found to provide the best fit for experimental data for both WSHs and PSHs. Standard error of estimate, %P and pseudo‐R2 values were: 0.00168 and 0.00248, 4.7 and 5.7%, and 0.963 and 0.974, respectively. Equilibrium relative humidity (ERH) values of PSHs were greater than those of WSHs at constant moisture content. Differential enthalpy (qst) and entropy (ΔSd) decreased exponentially with the increase in equilibrium moisture content, then became constant beyond 0.7 moisture content. qst and ΔSd values were larger for WSHs than PSHs. Enthalpy–entropy compensation was found to exist for both PSHs and WSHs. An entropy‐driven process was observed, with the free energy change (ΔG) for WSHs and PSHs of+0.0183 kJ/kg and−0.0284 kJ/kg, respectively. The spreading pressure was found to increase with the increase in ERH and decrease in temperature. The net integral enthalpy (ΔHi) decreased then reached an asymptote beyond a moisture content of 0.15 for both PSHs and WSHs. Net integral enthalpy was larger for WSHs. The net integral entropy (ΔSi) was negative for PSHs and WSHs, and ΔSi was greater in magnitude for PSHs.PRACTICAL APPLICATIONSSesame hulls are useful byproducts of sesame processing industry. Large amounts of this effluent are produced yearly in Jordan. They are used as livestock feed, but they require further dehydration to reduce moisture content and water activity into safe levels. In this project, drying thermodynamics of sesame hulls were discussed.