scholarly journals Mechanism of Moisture Adsorption In Plant Fibers Surface-Modified With Glycerol Evaluated By LF-NMR Relaxation Technique

2021 ◽  
Author(s):  
Lili Fu ◽  
Ke Zhang ◽  
Mingjian Zhang ◽  
Le Wang ◽  
Songjin Zheng ◽  
...  
Keyword(s):  
Moisture Transfer ◽  
Bound Water ◽  
Nmr Relaxation ◽  
Free Water ◽  
Diffusion Resistance ◽  
Plant Fibers ◽  
Moisture Adsorption ◽  
Adsorption Sites ◽  
Immobile Water ◽  
Lf Nmr

Abstract Surface modification by humectants is an important technology to improve product quality in textile field, healthcare, tobacco processing and paper-making industry. As a common humectant glycerol is applied to keep the moisture adsorbability of plant fibers during manufacturing. The effects of glycerol on the moisture adsorption of plant fibers were studied by analysising the induced differences of bulk and surface physicochemical property with XRD, FTIR, SEM characterizations. The improvement of moisture adsorption capacity of the modified plant fibers was due to the increased active adsorption sites, while the moisture diffusion resistance increased simultaneously with glycerol indicated by a declining Deff. LF-NMR relaxation spectra demonstrated the water sates and distributions in plant fibers were changed by loading glycerol. The moisture transfer mechanisms induced by glycerol were also investigated. Free water failed to materialize in the plant fibers treated with glycerol, immobile water existed preferentially during the adsorption, and bound water presented increasing after the immobile water were saturated. These findings are useful to improve the manufacturing processes of moisture-retaining properties of different functional plant fibers.

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.

Low Field-NMR in Measuring Water Mobility and Distribution in Beef Granules during Drying Process

2012 ◽  
Vol 550-553 ◽  
pp. 3406-3410 ◽  
Author(s):  
Xin Li ◽  
Li Zhen Ma ◽  
Yuan Tao ◽  
Bao Hua Kong ◽  
Pei Jun Li
Keyword(s):  
Bound Water ◽  
Free Water ◽  
Transverse Relaxation Time ◽  
Water Mobility ◽  
Drying Process ◽  
Transverse Relaxation ◽  
Low Field ◽  
Different Temperatures ◽  
Low Field Nmr ◽  
Lf Nmr

Low field-nuclear magnetic resonance (LF-NMR) was employed in this study to evaluate water mobility and distribution in beef granules during drying process due to its fast and nondestructive detection. Beef granules were dried in a blast drying oven at different temperatures (40, 50 and 60 °C) to a final moisture content around 21% after cooking. Results showed that it took about 150, 90 and 60 min for the samples dried at 40, 50 and 60 °C to get to the drying destination, respectively. The immobilized water was transformed into bound water with lower association degree and free water during drying at different conditions. Drying also resulted in a proportion increase of bound water; what’s more, the proportion of bound water is the largest when drying at 50 °C compared to 40 and 60 °C. After the drying destination was reached, the transverse relaxation time for bound water and immobilized water appeared significant change. It revealed that LF-NMR was an effective tool to assess water mobility and distribution during food drying process.

scholarly journals Low-Field NMR and MRI to Analyze the Effect of Edible Coating Incorporated with MAP on Qualities of Half-Smooth Tongue Sole (Cynoglossus Semilaevis Günther) Fillets during Refrigerated Storage

2018 ◽  
Vol 8 (8) ◽  
pp. 1391 ◽  
Author(s):  
Na Li ◽  
Yong Shen ◽  
Wenru Liu ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Modified Atmosphere Packaging ◽  
Bound Water ◽  
Free Water ◽  
Edible Coating ◽  
Refrigerated Storage ◽  
Structure Information ◽  
Tongue Sole ◽  
Low Field ◽  
Half Smooth Tongue Sole ◽  
Lf Nmr

Nondestructive and fast measurement and characterization of fish is highly desired during various processing treatments. This research investigated the effectiveness of low field LF-NMR and MRI as fast monitoring techniques to estimate the qualities of half-smooth tongue sole fillets treated with edible coating combined with modified atmosphere packaging during refrigeration. T2 relaxation spectra showed three peaks representing bound water (T21), immobile water (T22), and free water (T23), respectively. pT22 accounted for the largest proportion of three types of water, followed by pT23. The weighted MRI provided the internal structure information associated with different samples, indicting the combination of edible coating and MAP (70% CO2 + 30% N2) is the best performance in the maintenance of qualities and freshness of HTS fillets. All results demonstrated that the combination of LF-NMR and MRI as fast and nondestructive methods have great potential to monitor qualities deterioration and predict shelf life in of HTS fillets during refrigerated storage.

Water Dynamics and Physicochemical Analysis of Two Different Varieties of Apple Jam (Fuji) and (Yinduqing) by LF- NMR and MRI

2018 ◽  
Vol 14 (3) ◽  
Author(s):  
Tariq Kamal ◽  
Tan Zhang ◽  
Yukun Song ◽  
Bei-Wei Zhu ◽  
Mingqian Tan
Keyword(s):  
Magnetic Resonance ◽  
Water Content ◽  
Nmr Relaxation ◽  
Free Water ◽  
Water Dynamics ◽  
Soluble Solids ◽  
Sugar Concentration ◽  
Quality Analysis ◽  
Sugar Solution ◽  
Lf Nmr

AbstractApple jam is one of the favorite foods consumed worldwide. This study investigated the effect of storage time and sugar concentration on water dynamics inFujiandYinduqing, using low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) techniques. The samples were taken for jam preparation with various concentrations of sugar solution (0, 25, 50 and 75-oBrix) and stored at a room temperature of 20 °C for 16 days. The LF-NMR relaxation timeT2distribution displayed bound, intermediate and free water, respectively. The lowestT2range reflected lowest sugar hydrogen mobility depending on total soluble solids (TSS) and water content. A significant correlation (r> 0.9) existed between LF-NMR analysis and physicochemical parameters (water content, color, pH and TSS). MRI displayed uniform water distributions in samples with low sugar concentration. Fluorescence microscopy was used to evaluate sugar crystals and microstructural changes during processing. The study demonstrated the viability of LF-NMR method in determining water dynamics in the apple jams upon processing and storage that may be implemented for quality analysis in other jam products.

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

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 Testing the effects of basic numerical implementations of water migration on models of subduction dynamics

Solid Earth ◽  
2014 ◽  
Vol 5 (1) ◽  
pp. 537-555 ◽  
Author(s):  
M. E. T. Quinquis ◽  
S. J. H. Buiter
Keyword(s):  
Upper Mantle ◽  
Water Distribution ◽  
Mantle Wedge ◽  
Bound Water ◽  
Free Water ◽  
Water Velocity ◽  
Water Migration ◽  
Creep Flow ◽  
Dehydration Reactions ◽  
Slab Dehydration

Abstract. Subduction of oceanic lithosphere brings water into the Earth's upper mantle. Previous numerical studies have shown how slab dehydration and mantle hydration can impact the dynamics of a subduction system by allowing a more vigorous mantle flow and promoting localisation of deformation in the lithosphere and mantle. The depths at which dehydration reactions occur in the hydrated portions of the slab are well constrained in these models by thermodynamic calculations. However, computational models use different numerical schemes to simulate the migration of free water. We aim to show the influence of the numerical scheme of free water migration on the dynamics of the upper mantle and more specifically the mantle wedge. We investigate the following three simple migration schemes with a finite-element model: (1) element-wise vertical migration of free water, occurring independent of the flow of the solid phase; (2) an imposed vertical free water velocity; and (3) a Darcy velocity, where the free water velocity is a function of the pressure gradient caused by the difference in density between water and the surrounding rocks. In addition, the flow of the solid material field also moves the free water in the imposed vertical velocity and Darcy schemes. We first test the influence of the water migration scheme using a simple model that simulates the sinking of a cold, hydrated cylinder into a dry, warm mantle. We find that the free water migration scheme has only a limited impact on the water distribution after 1 Myr in these models. We next investigate slab dehydration and mantle hydration with a thermomechanical subduction model that includes brittle behaviour and viscous water-dependent creep flow laws. Our models demonstrate that the bound water distribution is not greatly influenced by the water migration scheme whereas the free water distribution is. We find that a bound water-dependent creep flow law results in a broader area of hydration in the mantle wedge, which feeds back to the dynamics of the system by the associated weakening. This finding underlines the importance of using dynamic time evolution models to investigate the effects of (de)hydration. We also show that hydrated material can be transported down to the base of the upper mantle at 670 km. Although (de)hydration processes influence subduction dynamics, we find that the exact numerical implementation of free water migration is not important in the basic schemes we investigated. A simple implementation of water migration could be sufficient for a first-order impression of the effects of water for studies that focus on large-scale features of subduction dynamics.

Characterization of thin water layers in pulp by tritium exchange. Part 1: Methods development

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Frances L. Walsh ◽  
Sujit Banerjee
Keyword(s):  
Water Content ◽  
Surface Area ◽  
Tritiated Water ◽  
Bound Water ◽  
Free Water ◽  
Fiber Surface ◽  
Bulk Water ◽  
Methods Development ◽  
A Value ◽  
A New Technique

Abstract A new technique for measuring the monolayer water content of fiber is presented. Tritiated water is added to a pulp/water suspension, whereupon the tritium partitions between the bulk water and the pulp. In the pulp phase the tritium can exchange with free water, bound water, and with hydroxyl and other protons present in the pulp matrix. The free water in the pulp is then removed by displacement with acetone. The tritium remaining in the pulp is mostly associated with tightly bound water, with a small fraction being tied up with the exchangeable hydrogen in pulp. The procedure provides a value of 10% for the tightly bound water content of hardwood or softwood fiber, either bleached or unbleached. If this water is assumed to cover the fiber surface as a monolayer, then an estimate of the wet surface area of the fiber can be obtained. This estimate compares well with independent measurements of surface area.

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.

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