scholarly journals Finite Changes of Bound Water Moisture Content in a Given Volume of Beech Wood

2015 ◽  
Vol 66 (4) ◽  
pp. 315-320
Author(s):  
Richard Hrčka
Keyword(s):  
Moisture Content ◽  
Beech Wood ◽  
Bound Water

scholarly journals Study on the Moisture Absorption and Thermal Properties of Hygroscopic Exothermic Fibers and Related Interactions with Water Molecules

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 98 ◽  
Author(s):  
Yi Cui ◽  
Shuyi Gao ◽  
Ruiyun Zhang ◽  
Longdi Cheng ◽  
Jianyong Yu
Keyword(s):  
Moisture Content ◽  
Thermal Performance ◽  
Water Sorption ◽  
Moisture Absorption ◽  
Bound Water ◽  
Absorption Process ◽  
Heating Performance ◽  
Hygroscopic Behavior ◽  
Water Sorption Capacity ◽  
Main Factor

The aim of this paper is to study the hygroscopic behavior of hygroscopic exothermic fiber-based materials and to obtain a better understanding of the thermal performance of these fibers during the moisture absorption process. The temperature distribution of different kinds of hygroscopic exothermic fibers in the process of moisture absorption, observed by infrared camera, demonstrated two types of heating performance of these fibers, which might be related to its hygroscopic behavior. Based on the sorption isotherms, a Guggenheim-Anderson-de Boer (GAB) multi-layer adsorption model was selected as the optimal moisture absorption fitting model to describe the moisture absorption process of these fibers, which illustrated that water sorption capacity and the water–fiber/water–water interaction had a significant influence on its heating performance. The net isosteric heats of sorption decreased with an increase of moisture content, which further explained the main factor affecting the heat dissipation of fibers under different moisture contents. The state of adsorbed water and water vapor interaction on the fiber surface were studied by simultaneous thermal analysis (TGA-DSC) measurement. The percentage of bound and unbound water formation at low and high humidity had a profound effect on the thermal performance of fibers. It can therefore be concluded that the content of tightly bound water a strong water–fiber interaction was the main factor affecting the heating performance of fibers at low moisture content, and the content of loosely bound water reflected that water sorption capacity was the main factor affecting the heating performance of fibers at high moisture content. This was further proven by the heat of desorption.

scholarly journals Measurement of leaf lamina moisture with a low-cost electrical humidity sensor: case study on a wheat water-mutant

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Agata Rascio ◽  
Michele Rinaldi ◽  
Giuditta De Santis ◽  
Nicola Pecchioni ◽  
Gabriele Palazzo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Electrical Resistance ◽  
Low Cost ◽  
Bound Water ◽  
Genotypic Differences ◽  
Wild Type ◽  
Leaf Lamina ◽  
Mature Leaves ◽  
Moisture Meter

Abstract Background The presence and persistence of water on the leaf can affect crop performance and thus might be a relevant trait to select for or against in breeding programmes. Low-cost, rapid and relatively simple methods are of significant importance for screening of large populations of plants for moisture analysis of detached leaves. Leaf moisture can be detected using an electric circuit, where the resistance changes are proportional to the moisture of the measured surface. In this study, we present a protocol to analyse genotypic differences through the electrical properties of living or stored tissues, performed using a commercial device. Expanded and non-expanded leaves were compared to determine the effects of leaf maturity on these data. Two wheat genotypes that differ in tissue affinity for bound water were used to define the influence of water status. Results The device indirectly estimates leaf moisture content using two electrodes applied to the leaf lamina of fresh and stored samples. Single moisture readings using this moisture meter had mean execution time of ~ 1.0 min. Exponential associations provided good fits for relationships between the moisture meter reading (MMR) and the electrical resistance applied to the electrodes. MMR normalised for the water/ dry matter ratio (MMRnorm) was lower for mature leaves of the water-mutant than those of wild-type, for the fully hydrated fresh leaves. MMR of fully mature leaves when partially dehydrated and measured after 10 min at 27 °C and 40% relative humidity was greater for the water-mutant than the wild-type. Conclusions This case study provides a low-cost tool to compare electrical-resistance estimates of leaf moisture content, together with a promising and rapid phenotyping protocol for genotypic screening of wheat under standard environmental conditions. Measurement of changes in MMR with time, of fresh and partially dehydrated leaves, or of MMR normalised to tissue water content allowed for differentiation between the genotypes. Furthermore, the differences observed between genotypes that here relate particular to tissue affinity for bound water suggest that not only the free-water fraction, but also other water fractions, can affect these electrically estimated leaf moisture measures.

scholarly journals Development of a Device for Staged Determination of Water Activity and Moisture Content

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 881 ◽  
Author(s):  
Carlo Tiebe ◽  
Marc Detjens ◽  
Annika Fechner ◽  
Stefanie Sielemann ◽  
Andreas Lorek ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Activity ◽  
Bound Water ◽  
Free Water ◽  
Characteristic Parameter ◽  
Industrial Applications ◽  
Wide Range ◽  
Temperature Equilibrium

Moisture content and water activity are important parameters for quality characterizationof products like bulk materials, powders, granules. Thus, an exact determination is necessarilyrequired in a wide range of industrial applications. Moisture of materials is the content ofnon-chemically bound water in a solid or liquid. Water activity (aw) is a characteristic/parameter ofthe non-chemically bound (“free”) water in materials and is measured as humidity over asolid/liquid surface at constant temperature (equilibrium moisture content). It is an importantparameter to characterize the quality of e.g., pharmaceutical and food products. In ourcontribution, we present the developed MOISHUM device for staged determination of wateractivity and moisture content of liquid and solid materials.

DSC and SEM Analysis on Bound Water Characteristics in Sewage Sludge

2011 ◽  
Vol 347-353 ◽  
pp. 2085-2089 ◽  
Author(s):  
Wei Yun Wang ◽  
Ai Min Li ◽  
Xiao Min Zhang
Keyword(s):  
Liquid Phase ◽  
Sewage Sludge ◽  
Moisture Content ◽  
Differential Scanning Calorimeter ◽  
Bound Water ◽  
Water Structure ◽  
Sem Analysis ◽  
Water Characteristics ◽  
Water Based ◽  
Calculation Results

Water structure present in sewage sludge with different moisture content was analyzed by differential scanning calorimeter(DSC).The sharp endothermic peaks that appeared at 6.14°C(95.87%wet basis),5.22°C(87.20%wet basis),1.33°C(71.20%wet basis).The calculation results , amount of bound water based on peak temperature and peak area, could account for stick phase of sewage sludge combined with SEM analysis results. Finally,mechanical mechanism of different phases(liquid phase, sticky phase, granule phase) were tentively described by schematic diagrams.

scholarly journals Calibration of Electrical Resistance to Moisture Content for Beech Laminated Veneer Lumber “BauBuche S” and “BauBuche Q”

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 635
Author(s):  
Philippe Grönquist ◽  
Gianna Weibel ◽  
Claude Leyder ◽  
Andrea Frangi
Keyword(s):  
Moisture Content ◽  
Electrical Resistance ◽  
High Performance ◽  
Beech Wood ◽  
Gravimetric Method ◽  
Model Parameters ◽  
Data Set ◽  
Laminated Veneer Lumber ◽  
Calibration Models ◽  
Different Depths

Electrical resistance measurements are often employed for the purpose of nondestructive long-term monitoring of wood moisture content (MC) in timber structures. As a structural material for high-performance load-bearing applications in such structures, beech laminated veneer lumber (LVL) enjoys a growing popularity. However, due to the processing of beech LVL affecting physical properties, calibration curves for bulk beech wood cannot be used. In this study, resistance was measured on 160 beech LVL samples equilibrated in four different relative humidity (RH) climates. The results show a difference not only between the beech LVL products “BauBuche S” and “BauBuche Q”, but also between measurements at two different depths. For each data set, parameters for calibration models using two and using three model parameters were determined by regression analysis to MC determined by the gravimetric method.

scholarly journals Effects of Moisture Content and Grain Direction on the Elastic Properties of Beech Wood Based on Experiment and Finite Element Method

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 610
Author(s):  
Wei-Lian Fu ◽  
Hui-Yuan Guan ◽  
Sawata Kei
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Content ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Beech Wood ◽  
Wood Products ◽  
Moisture Contents ◽  
Wide Range ◽  
Element Method

Beech wood (Fagus sylvatica L.) is used in a wide range of wood products. However, the influence of the wood’s moisture content on its mechanical functions will affect its structural strength. It would be complicated and time-consuming to experimentally measure wood’s mechanical functions under different moisture contents. Therefore, it is necessary to establish a prediction formula between the moisture content and elastic constants, and then verify whether its mechanical functions within a wide range of moisture content can be studied by using FEM (finite element method). In this study, which was based on experimentation, we studied the influence of a wide range of moisture contents and grain direction on the compressive yield strength, modulus of elasticity and shear modulus of beech wood. The relationship between the moisture content and elastic constants was established; the moisture sensitivities of different elastic parameters were obtained. Ultimately, compression curves under different moisture contents were plotted out, using both FEM and experimentation. According to the results, the interaction of moisture with the grain direction had a significant effect on the elastic constants of wood, with grain direction having a greater effect on the elastic properties than the moisture content. Moreover, the decay function can be used to fit these experimental results well. The elastic constants of beech wood responded differently to the moisture content, depending on whether it was in the longitude or transverse directions. Finally, this study proved the feasibility of using FEM to simulate wood’s compressive performance with a wide range of moisture contents.

scholarly journals Hygroscopicity of Longitudinally Compressed Wood

2017 ◽  
Vol 13 (2) ◽  
pp. 135-144 ◽  
Author(s):  
Mátyás Báder ◽  
Róbert Németh
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Beech Wood ◽  
Research Work ◽  
Modification Method ◽  
Vapour Adsorption ◽  
Long Time ◽  
The Difference ◽  
Compressed Wood ◽  
Control Samples

AbstractKnowledge of hygroscopicity is extremely important both in the use of native wood and modified wood. In this study, the modification method was steaming at 100 °C, then longitudinal compression at a rate of 20%. The moisture content (MC) of treated and untreated green beech wood (Fagus sylvaticaL.) was reduced in a climate chamber with gradual reduction of air humidity at 20 °C. The difference of calculated fibre saturation points between control samples and samples compressed for a long time was 6% (MC%). In the course of desorption, this difference decreased, and finally disappeared at 10% moisture content (40% relative humidity). In the second step of the research work, the speed of vapour adsorption was checked. The absolute dry samples were placed in air with 95% relative humidity. The highest deviation in the moisture content was 1% (MC%) between the control and the compressed samples. The compressed wood dries faster than the control samples under the same conditions. Furthermore, during adsorption, the moisture content of the compressed samples at room conditions is lower.

scholarly journals Influence of Moisture Content on the Strength of Finger Joints Bonded Beech Wood

2021 ◽  
pp. 0270-0274
Author(s):  
Alen Ibrisevic ◽  
Murco Obucina ◽  
Seid Hajdarevic ◽  
Goran Mihulja
Keyword(s):  
Moisture Content ◽  
Beech Wood ◽  
Finger Joints
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