scholarly journals The Effect of Contact-Drying on Physical Properties of European Beech (Fagus sylvatica L.)

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 890
Author(s):  
Ivan Klement ◽  
Peter Vilkovský ◽  
Tatiana Vilkovská
Keyword(s):  
Beech Wood ◽  
Bound Water ◽  
Free Water ◽  
European Beech ◽  
Average Density ◽  
Sample Thickness ◽  
Air Drying ◽  
Contact Drying ◽  
The Difference ◽  
Two Phases

Beech wood is mainly used for furniture, plywood, decorative veneer manufacturing or packaging. Timber or lumber is traditionally dried in kilns by processes often taking several weeks. This research deals with more rapid process called contact-drying process. Drying was performed using the heating plates with a temperature of 160 °C and pressures of 1.0 MPa, 1.4 MPa and 1.8 MPa. The results were compared to conventional warm-air drying. The warm-air drying mode was divided into two phases, with and without free water and bound water in the dried wood. The density of the samples increased remarkably during the contact-drying. The effect of the pressure of the heating plates was substantial. The difference in the average density between the pressure of 1.0 MPa and 1.8 MPa was more than 22 kg·m−3. The pressure of the heating plates affected the process and the resulting change in the sample thickness. The change in the sample thickness was more considerable in the case of the tangential samples. The thickness did not increase significantly after air conditioning. During contact-drying, the hygroscopicity and absorptivity of wood reduced on average by 21.24% and 25%, respectively, compared to warm-air drying.

scholarly journals Dielectrometry of hydration of fl avin mononucleotide and DNA

2021 ◽  
Vol 26 (3) ◽  
pp. 46-53
Author(s):  
V. Kashpur ◽  
◽  
O. Khorunzhaya ◽  
D. Pesina ◽  
◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Bound Water ◽  
Free Water ◽  
Dna Interaction ◽  
Flavin Mononucleotide ◽  
Water Molecules ◽  
Extremely High Frequency ◽  
Aqueous Solvent ◽  
The Difference ◽  
Solvent Molecules

Subject and Purpose. The elucidation of the molecular mechanisms of action of biomolecules is necessary for the development of state-of-the-art means of diagnosing and treatment. Dielectric studies in the millimeter wave range are effective for puzzling out the nature of the interaction of biomolecules with a surrounding aqueous solvent. Flavin mononucleotide (FMN), which can kill microorganisms and destroy cancer cells, is of particular interest. The aim of the work is to recognize hydration effects (changes in the state of water molecules) in FMN solutions. Methods and Methodology. The complex dielectric permittivity (CDP) is measured in the EHF range. Knowing the difference between the CDP of FMN solution and the CDP of water we find the difference, D es , between the effective dielectric permittivities in terms of the Debye theory of polar liquids. Since the relaxation time of dipoles of bound water is one or two orders of magnitude longer than that of free water, the amount of the difference D es characterizes the hydration of biomolecules. At low concentrations, this difference is proportional to the number of bound water molecules. Results. It has been shown that approximately18 water molecules are bound to the FMN molecule. Groups of atoms as the most probable hydration centers (primarily due to the hydrogen bonds) have been indicated. As the pH decreases, the number of water molecules bound to the Flavin mononucleotide increases to 21. The study of the FMN–DNA solution has shown that one nucleotide accounts for 25–26 bound water molecules in total. However, composing hydration numbers assumes a quantity of components less than 20. An assumption is made that the additional components are due to the cooperative nature of the hydration, leading to the fact that even if some solvent molecules do not come into a direct contact with hydration centers, they are under the influence of biomolecules all the same. Conclusion. Extremely-high-frequency dielectrometry is an effective method of research into the interaction of biomolecules with a water-ionic solvent. A FMN hydration model has been proposed, which indicates probable hydration centers and tells a measure of their effect on the solvent. It has been found that the FMN with DNA interaction increases the number of bound water molecules per one nucleotide of the DNA. The obtained results have been compared to the existing models of the DNA with FMN interaction.

scholarly journals Selected properties of European beech (Fagus sylvatica L.)

2008 ◽  
Vol 54 (No. 9) ◽  
pp. 418-425 ◽  
Author(s):  
V. Gryc ◽  
H. Vavrčík ◽  
Š. Gomola
Keyword(s):  
Wood Density ◽  
Beech Wood ◽  
Ring Width ◽  
European Beech ◽  
Average Density ◽  
Tree Ring Width ◽  
Vegetation Zone ◽  
Significant Difference ◽  
Insignificant Difference ◽  
Outer Perimeter

The paper deals with the variability of tree-ring width, with the density and swelling (volumetric swelling and swelling in individual anatomical directions) of wood from two different locations. Further, the variability of the explored properties along the stem radius is researched. The ring analyses show that the ring width decreases along the stem radius from the pith to the stem outer perimeter. Location 2 (a lower altitudinal vegetation zone) had on average wider rings (a statistically insignificant difference), higher density and higher volumetric swelling of wood in comparison with location 1 (a statistically significant difference). The relation between volumetric swelling and wood density has been confirmed. The results show that the wood density and its volumetric swelling change along the stem radius. With the increasing wood density the volumetric swelling also increases. The average density of beech wood from both locations is 752 kg/m<sup>3</sup> with moisture content of 12%.

Rapid and nondestructive evaluation of hygroscopic behavior changes of thermally modified softwood and hardwood samples using near-infrared hyperspectral imaging (NIR-HSI)

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Te Ma ◽  
Laurence Schimleck ◽  
Tetsuya Inagaki ◽  
Satoru Tsuchikawa
Keyword(s):  
Hyperspectral Imaging ◽  
Curve Fitting ◽  
Near Infrared ◽  
Bound Water ◽  
Japanese Cedar ◽  
European Beech ◽  
Imaging Method ◽  
Nmr Studies ◽  
The Difference ◽  
Hygroscopic Behavior

AbstractThe objective of this work was to provide a rapid and nondestructive imaging method for evaluating the hygroscopic behavior of thermally modified lignocellulosic materials (softwood and hardwood). The difference in the hygroscopic behavior was explained by moisture content (MC) mapping results and molecular association characteristics of absorbed water (i.e. weakly, moderately, and strongly hydrogen-bonded water molecules) with wood at various relative humidities (RH). To achieve this goal, near-infrared (NIR) spectral images in the wavelength range 1816–2130 nm (covering the combination of stretching and deformation vibrations for OH) were used to visualize MC distributions over the surface of Japanese cedar and European beech samples which had been thermally treated at different temperatures. A curve fitting method was utilized to explore changes in water-wood structure characteristics based on shifts to longer wavelength in spectral signals caused by increasing MC. The curve fitting results support the recent nuclear magnetic resonance (NMR) studies that different bound water stabilities may pool in different compartments of the wood cell wall. Furthermore, water was firmly bound to wood at low RHs and H-bonds gained mobility as the number of absorbed molecules increased. It is concluded that NIR hyperspectral imaging also has the potential to be a complementary methodology for studying the transient changes of wood-water interactions before equilibrium.

BOUND WATER, INOSITOL, AND THE EFFECT OF X-RAYS ON ESCHERICHIA COLI

1964 ◽  
Vol 10 (6) ◽  
pp. 877-885 ◽  
Author(s):  
S. J. Webb ◽  
M. D. Dumasia
Keyword(s):  
Escherichia Coli ◽  
Bound Water ◽  
Free Water ◽  
Sharp Decrease ◽  
Water Molecules ◽  
X Rays ◽  
X Ray ◽  
Water Layers ◽  
The Difference ◽  
Escherichia Coli B

Aerosols of Escherichia coli B were subjected to 250 kv X-rays. It was found that maximal X-ray damage occurred at 70 to 80% relative humidity (R.H.). At these R.H. values only the water bound directly to cell macromolecules remains, and if the water layers were increased by using higher humidities, X-ray damage decreased. Also, at R.H. levels below 70% a sharp decrease in the sensitivity of the cells to the radiation occurred. Several chemicals known to protect cells against desiccation, ultraviolet, and X-ray damage were examined and of these i-inositol proved the most successful. The difference in the protective ability of these various compounds indicated that some protect cells against desiccation damage by retaining water, others by replacing bound-water molecules in macromolecular structure but those retaining water will not protect against X-rays. The results suggest that the physical removal or ionization of a strategic bound-water molecule by X-rays causes most of the cell deaths rather than ionizations occurring in the free water as the presence of the latter appears to offer cells a measure of protection.

Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process

2021 ◽  
Vol 114 ◽  
pp. 86-91
Author(s):  
Ladislav Dzurenda
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Bound Water ◽  
Free Water ◽  
Hot Air Drying ◽  
Air Drying ◽  
Water Steam ◽  
Color Changes ◽  
Hot Air ◽  
Relative Air Humidity

Mode for hot air drying of alder blanks that retain the colour acquired during the steaming process. The paper presents a hot-air mode for drying steamed alder in the form of blanks with dimensions: 38x100x800 mm from the initial moisture content W1 ≈ 50 % to the final moisture content W2 = 10%, while maintaining the colour of wood obtained in the process of steaming with saturated water steam. The drying process is divided into two parts: (I) evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and relative air humidity φ = 70 – 60%, when there are no chemical changes in the lignin-saccharide complex of alder wood manifested by a change in colour; (II) evaporation of bound water from alder wood below the hygroscopicity limit is performed at temperatures td = 60 - 80 °C. The color coordinates of steamed alder wood after drying by a given mode in the CIE L* a* b* colour space are: L* = 62.5 ± 1.7; a* = 13.1 ± 0.8; b* = 18.5 ± 0.9. Total colour difference ∆E = 1.6. According to the categorization of wood color changes in thermal processes of wood , this change belongs to small (insignificant) color changes.

scholarly journals Experimental and Numerical Investigations on Conductive Drying of Phosphate Washing Waste Clay

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 482
Author(s):  
Fatiha Berroug ◽  
Yassir Bellaziz ◽  
Naaila Ouazzani ◽  
Fatima Ait Nouh ◽  
Abdessamad Hejjaj ◽  
...  
Keyword(s):  
Scale Up ◽  
Free Water ◽  
Moisture Diffusivity ◽  
Sample Thickness ◽  
Total Production ◽  
Drying Process ◽  
One Dimensional ◽  
Numerical Investigations ◽  
The World ◽  
Drying System

Morocco is the leading producer of phosphate and its derivatives in the world with a total production of 35 Mt. However, the extraction and the valorization of this mine generate huge quantities of phosphate washing waste clay (PHWWC) that constitute a main environmental and economic concern. To facilitate this waste clay storage and handling, it is necessary to decrease its moisture content that represents 80% of PHWWC. The present paper is devoted to studying the conductive drying of PHWWC. Drying experiments were conducted in a laboratory pilot. Afterwards, the experiment results were implemented in a one-dimensional numerical model of heat and mass transfer in a porous media to identify the drying parameters and performances. It was found that most of the water contained in PHWWC is free water that is removed with a constant drying rate. The volume reduction with a marked cracks phenomenon attained 65% without any significant effect of drying temperature and sample thickness. The effective moisture diffusivity of the PHWWC for a conductive drying process is ranged between 10−9 and 1.1 × 10−8 m2·s−1. The thermal efficiency of the drying system is up to 86%. The results could be used for the purpose of design and scale-up of the industrial dryer based on laboratory-scale experiments.

Determine the Moisture Distribution in Sewage Sludge by Drying Differential

2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li
Keyword(s):  
Sewage Sludge ◽  
Interstitial Water ◽  
Bound Water ◽  
Free Water ◽  
High Accuracy ◽  
Moisture Distribution ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Hot Air ◽  
Critical Water Content

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.

scholarly journals SPECTRAL CORRELATIONS IN DISORDERED MESOSCOPIC METALS AND THEIR RELEVANCE FOR PERSISTENT CURRENTS

1996 ◽  
Vol 10 (28) ◽  
pp. 1397-1406 ◽  
Author(s):  
AXEL VÖLKER ◽  
PETER KOPIETZ
Keyword(s):  
Energy Levels ◽  
Three Dimensional ◽  
Average Density ◽  
Electron Interaction ◽  
Energy Window ◽  
Persistent Currents ◽  
Dependent Part ◽  
The Difference ◽  
Aharonov Bohm ◽  
Grand Canonical

We use the Lanczos method to calculate the variance σ2(E, ϕ) of the number of energy levels in an energy window of width E below the Fermi energy for noninteracting disordered electrons on a thin three-dimensional ring threaded by an Aharonov–Bohm flux ϕ. We confirm numerically that for small E the flux-dependent part of σ2(E, ϕ) is well described by the Altshuler–Shklovskii-diagram involving two Cooperons. However, in the absence of electron–electron interactions this result cannot be extrapolated to energies E where the energy-dependence of the average density of states becomes significant. We discuss consequences for persistent currents and argue that for the calculation of the difference between the canonical- and grand canonical current it is crucial to take the electron–electron interaction into account.

Free Water Influence on the Dynamic Tensile Behaviour of Concrete

2011 ◽  
Vol 82 ◽  
pp. 45-50 ◽  
Author(s):  
Benjamin Erzar ◽  
Pascal Forquin
Keyword(s):  
Dynamic Behaviour ◽  
Free Water ◽  
Dynamic Strength ◽  
Fragmentation Process ◽  
Tensile Behaviour ◽  
Water Influence ◽  
Micro Cracks ◽  
The World ◽  
The Difference ◽  
Impact Experiments

Concrete is a material used all over the world for civil engineering but the mechanisms governing its dynamic behaviour are still not well understood. In this work, spalling tests and edge-on impact experiments have been used to determine the influence of the free-water contained in pores and micro-cracks on the dynamic strength and on the fragmentation process. Moreover, spalling tests have been also used to identify the main mechanisms leading to the difference of behaviour observed between wet and dry concrete.

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