Study on the Moisture Distribution within the Wood Treated with Microwave

2011 ◽  
Vol 327 ◽  
pp. 105-108 ◽  
Author(s):  
Jian Fang Yu ◽  
Ji Long Guo ◽  
Jing Ya Nan ◽  
Bing Hu Sun
Keyword(s):  
Relaxation Time ◽  
Bound Water ◽  
Free Water ◽  
Microwave Treatment ◽  
Moisture Distribution ◽  
Microwave Drying ◽  
Water Molecules ◽  
Saturation Point ◽  
Initial Stage ◽  
Before And After

In this paper, Siberian elm (Ulmus pumila L) which was regarded as our research object was measured with the technology of Nuclear Magnetic Resonance (NMR) before and after being treated with microwave at different periods of time. By comparing the spin - spin relaxation time of hydrogen nuclear (T2) which can reflect the mobility of water molecules, the states and changes of the moisture distribution within the wood in the process of microwave treatment have been analyzed. The results indicate that in the initial stage of drying, the degree of the decline in bound water is greater than that in free water, for there may be a process of the transformation from bound water to free water; With the drying going on, the movement and expulsion mainly happen to free water above the fiber saturation point (FSP); In the later stage of drying, when the moisture content decreases near the FSP, bound water has also begun moving significantly on the expulsion of plenty of free water. In the final stage of drying, the decrease of hydrogen bonds in water molecules resulting from a plentiful reduction in free water, as well as the increased permeability within the wood caused by the microwave drying makes the relaxation time of free water to rise up.

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 Water Adsorption to Leaves of Tall Cryptomeria japonica Tree Analyzed by Infrared Spectroscopy under Relative Humidity Control

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1107
Author(s):  
Wakana A. Azuma ◽  
Satoru Nakashima ◽  
Eri Yamakita ◽  
Tamihisa Ohta
Keyword(s):  
Hydrogen Bonding ◽  
Relative Humidity ◽  
Cryptomeria Japonica ◽  
Water Adsorption ◽  
Bound Water ◽  
Free Water ◽  
High Water ◽  
Water Molecules ◽  
Cross Sectional ◽  
Tissue Properties

Leaf water storage is a complex interaction between live tissue properties (anatomy and physiology) and physicochemical properties of biomolecules and water. How leaves adsorb water molecules based on interactions between biomolecules and water, including hydrogen bonding, challenges our understanding of hydraulic acclimation in tall trees where leaves are exposed to more water stress. Here, we used infrared (IR) microspectroscopy with changing relative humidity (RH) on leaves of tall Cryptomeria japonica trees. OH band areas correlating with water content were larger for treetop (52 m) than for lower-crown (19 m) leaves, regardless of relative humidity (RH). This high water adsorption in treetop leaves was not explained by polysaccharides such as Ca-bridged pectin, but could be attributed to the greater cross-sectional area of the transfusion tissue. In both treetop and lower-crown leaves, the band areas of long (free water: around 3550 cm−1) and short (bound water: around 3200 cm−1) hydrogen bonding OH components showed similar increases with increasing RH, while the band area of free water was larger at the treetop leaves regardless of RH. Free water molecules with longer H bonds were considered to be adsorbed loosely to hydrophobic CH surfaces of polysaccharides in the leaf-cross sections.

Water migration in poplar wood during microwave drying studied by time domain nuclear magnetic resonance (TD-NMR)

Holzforschung ◽  
2017 ◽  
Vol 71 (11) ◽  
pp. 881-887 ◽  
Author(s):  
Xinyu Li ◽  
Yulei Gao ◽  
Minghui Zhang ◽  
Ximing Wang ◽  
Xinyue Wei
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Time Domain ◽  
Bound Water ◽  
Free Water ◽  
Microwave Drying ◽  
Drying Rate ◽  
Drying Time ◽  
The Time Domain ◽  
Nuclear Magnetic

AbstractThe migration of bound water and free water has been investigated during microwave drying of wood by the time domain nuclear magnetic resonance (TD-NMR) technique. Both the heartwood (hW) and sapwood (sW) of Beijing poplar (Populus beijingensisW. Y. Hsu) and Qingpi poplar (Populus platyphyllaT. Y. Sun) were studied. The microwave drying is characterized by a fast drying rate, and there is a linear relation between moisture content (MC) and microwave drying time (t). The drying rate of free water is about 2.7 times more rapid than that of bound water. The spin-spin relaxation time (T2) revealed that most of the water was free water situated in smaller pores. The irregular T2 signal amplitudes of free water in hWs indicated that fractional water in smaller pores was transferred into bigger pores during drying.

Moisture in softwoods: fiber saturation point, hydroxyl site content, and the amount of micropores as determined from NMR relaxation time distributions

Holzforschung ◽  
2013 ◽  
Vol 67 (3) ◽  
pp. 291-300 ◽  
Author(s):  
Ville-Veikko Telkki ◽  
Miikka Yliniemi ◽  
Jukka Jokisaari
Keyword(s):  
Melting Point ◽  
Relaxation Times ◽  
Bound Water ◽  
Nmr Relaxation ◽  
Free Water ◽  
Bulk Water ◽  
Fiber Saturation Point ◽  
Saturation Point ◽  
Fiber Saturation ◽  
Nmr Relaxation Times

Abstract Distributions of nuclear magnetic resonance (NMR) relaxation times provide detailed information about the moisture absorbed in wood. In this work, T2*, T2, and T1 distributions were recorded from fresh sapwood and heartwood samples of pine (Pinus sylvestris) and spruce (Picea abies) at various temperatures. Below the melting point of bulk water, free water is frozen and its signal disappears from the distributions. Then, the low-temperature distributions of the unfrozen bound water contain more information about its components, because the large free water peaks hiding some smaller bound water peaks are absent and the exchange between free and bound water is prevented. Comparison of the total moisture signal integrals above and below the bulk melting point enables the determination of fiber saturation point (FSP), which, in this context, denotes the total water capacity of cell wall. T2*, T2, and T1 distributions offer different kinds of information about moisture components. All the peaks in the distributions were assigned, and it was demonstrated that the accessible hydroxyl site content and the amount of micropores can be estimated based on the peak integrals.

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 Effects of Bamboo Shoot Dietary Fiber on Mechanical Properties, Moisture Distribution, and Microstructure of Frozen Dough

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Hua Zhang ◽  
Yanyan Zhang ◽  
Xintian Wang ◽  
Qisen Xiang ◽  
Yanhong Bai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dietary Fiber ◽  
Bound Water ◽  
Free Water ◽  
Moisture Distribution ◽  
Dependent Manner ◽  
Bamboo Shoot ◽  
Scanning Calorimetry ◽  
Frozen Dough ◽  
Addition Amount

In this paper, the effects of Bamboo shoot dietary fiber (BSDF) on the mechanical properties, moisture distribution, and microstructure of frozen dough were investigated. The state and distribution of water in frozen dough was determined by differential scanning calorimetry (DSC) and low-field nuclear magnetic resonance (LNMR) spectroscopy. The microstructure of frozen dough was studied. The structure of the gluten protein network found in wheat flour dough was studied by scanning electron microscopy (SEM). The result showed that the BSDF could significantly improve the viscoelasticity and extensibility of frozen dough after thawing in a dose-dependent manner. It was significantly improved with the increase in the addition amount of BSDF (P<0.05). DSC analysis showed that the freezable water content and thermal stability of frozen dough were increased after the addition of BSDF. LNMR analysis showed that the appropriate (<0.1%) addition amount of BSDF could significantly (P<0.05) decline the contents of bound water. Meanwhile, the loose bound water and free water were raised significantly (P<0.05) after the addition of BSDF. Moreover, the addition of BSDF induces arrangement of starch granule and gluten network in frozen dough. BSDF can be used as a novel quality improver of frozen dough.

scholarly journals Measurement and Modelling of Moisture Distribution and Water Binding Energy of Dredged Sludge

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3395
Author(s):  
Feiyan Mao ◽  
Yingjie Zhao ◽  
Yiping Zhang ◽  
Zhou Chen ◽  
Lu Yin
Keyword(s):  
Binding Energy ◽  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Moisture Distribution ◽  
Water Binding ◽  
Dredged Sludge ◽  
Urban Watercourse ◽  
Experimental Values ◽  
Stage 1

The dewatering of dredged sludge is a critical step in the minimization and reutilization of this solid waste. However, there is a lack of available literature on the fundamental drying characteristics of dredged sludge. In this work, two kinds of typical sludge dredged from an urban watercourse were tested by low-field NMR to investigate the water distribution in sludge and it was found that water contained in sludge can be classified into three categories: free water, capillary water and bound water. In addition, a novel model was proposed based on the Lennard-Jones equation and Kelvin law to quantitatively evaluate the binding energy during drying. Further, the model results were experimentally verified by thermogravimetry differential thermal analysis (TG-DTA). Results show that the trends of the model are consistent with the experimental values and the gradient of energy consumption during dehydration can be divided into three main stages. In stage 1, the total energy required for dewatering equals the latent heat of free water. In stage 2, binding energy reaches dozens to hundreds of kJ/kg accounting for capillary action. In stage 3, binding energy increases steeply reaching almost thousands of kJ/kg due to intermolecular interactions. All the discovered aspects could improve the management and disposal of dredged sludge from an energy cost perspective.

scholarly journals Drying influence on the development of cracks in Eucalyptus logs

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 220-233
Author(s):  
Thiago Magalhães do Nascimento ◽  
Thiago Campos Monteiro ◽  
Edy Eime Pereira Baraúna ◽  
Jordão Cabral Moulin ◽  
Alcinei Mistico Azevedo
Keyword(s):  
Moisture Content ◽  
Water Loss ◽  
Initial Moisture Content ◽  
Genetic Material ◽  
Bound Water ◽  
Free Water ◽  
Moisture Loss ◽  
Surface Cracks ◽  
Saturation Point ◽  
Selection Of

The aim of this study was to evaluate the effect of the moisture loss, diameter, and wood density on the appearance of surface cracks and end splits in Eucalyptus urophylla logs. The drying and emergence of defects were evaluated in 108 logs with diameters ranging from 60 mm to 150 mm from the initial moisture content to the equilibrium moisture content. The defects were measured during this time. Smaller diameter logs dried faster than larger diameter logs and took less time to reach the fiber saturation point. Surface cracks tended to develop during the loss of bound water. End splits developed during free water loss and continued to appear during bound water loss. Smaller diameters presented higher percentages of surface cracks compared with larger diameters, while larger diameters had a tendency for higher percentages of end splits compared with smaller diameters. The density did not influence the total emergence of end splits, but it did influence the total emergence of surface cracks, indicating a possibility for the selection of genetic material with lower tendency for cracking. Overall, the results reinforce the need to control drying at its beginning in order to decrease the risk of defects.

Assessment of Bone Quality Associated With Loosely and Tightly Bound Water

2010 ◽  
Author(s):  
Qingwen Ni ◽  
Naniel P. Nicolella
Keyword(s):  
Bone Strength ◽  
Bone Quality ◽  
Water Distribution ◽  
Mechanical Test ◽  
Bound Water ◽  
Free Water ◽  
Water Molecules ◽  
Surface Charges ◽  
Mobile Water ◽  
Age Related

Previous studies have shown that the age-related increase in bone porosity results a decrease in bone strength, and porosity is related to the volume of mobile water in the pores. In addition, since water is also bound to collagen and mineral, changes in the amount of bound water will potentially affect the bone strength. It is known that the removal of the loosely bound water (via hydrogen bonding) requires less energy than the water molecules trapped inside collagen molecules, which in turn requires similar or less energy than water molecules bound to the surface charges of mineral apatite (more ionic in nature). Also, water that is imbedded in the lattice of hydroxyapatite (more covalent in nature) requires the highest energy to dislodge. However, there is no traditional method that can determine mobile and bound water, further for loosely and tightly bound ware accurately, non-destructively and non-invasively. Here, we propose that by using NMR Car-Purcell-Meiboom-Gill (CPMG) spin-spin relaxation measurement to determine the mobile water, and the NMR inversion T2-FID spectrum derived from NMR free induction decay (FID) measurements for estimating the bound and free water distribution. Furthermore, after comparison of the total water lost (weighing method) within tissue by using drying (free dry) on the air to the total mobile water lost measured by NMR CPMG method, then, the total loosely bound water lost can be estimated. Following this, the mechanical test will be used to evaluate the bone quality related to the tightly and loosely bound water within bone. This information can be used to further assessment of bone quality.

Water states and migration in Xinjiang poplar and Mongolian Scotch pine monitored by TD-NMR during drying

Holzforschung ◽  
2018 ◽  
Vol 72 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Zhe Wang ◽  
Xi-Ming Wang ◽  
Zhang-Jing Chen
Keyword(s):  
Bound Water ◽  
Free Water ◽  
Scotch Pine ◽  
Saturation Point ◽  
Time Component ◽  
Long Time ◽  
And Migration ◽  
The Time Domain ◽  
Short Time ◽  
Bound Water Content

AbstractThe time domain nuclear magnetic resonance (TD-NMR) technique was applied to observe the water states, water migration and theT2cutoffof sapwood (sW) and heartwood (hW) of Xinjiang poplar and Mongolian Scotch pine wood during drying. Three components in theT2spectrum could be observed for poplar and pine at room temperature, and a large, short time component and a small, long time component of free water was visible at the melting point of water. During drying, the long timeT2component diminished rapidly above the fiber saturation point (FSP), and almost disappeared close to or below the FSP. The short time components of theT2distributions slightly enlarged with decreasing moisture content (MC) above the FSP but rapidly diminished and shifted to the left side below the FSP. The bound water content estimated based on theT2cutoffis in agreement with previous findings. Free and bound water have been found to be in two primary states both in poplar and pine. The loss of free water was rapid and profound but the bound water slightly increased with decreasing MC above the FSP, and the free water evaporated completely close to the FSP, where the bound water began to disappear significantly.

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