Resolving the Contradiction between Anomalously High Water Uptake and Low Conductivity of Nanothin Nafion films on SiO2 Substrate

2015 ◽  
Vol 48 (22) ◽  
pp. 8394-8397 ◽  
Author(s):  
Hyun Ki (Key) Shim ◽  
Devproshad K. Paul ◽  
Kunal Karan
Keyword(s):  
Water Uptake ◽  
High Water ◽  
Sio2 Substrate

Hydraulic segmentation does not protect stems from acute water loss during fire

2021 ◽  
Author(s):  
William A Hoffmann ◽  
Amanda C Rodrigues ◽  
Nicholas Uncles ◽  
Lorenzo Rossi
Keyword(s):  
Water Uptake ◽  
Water Loss ◽  
High Water ◽  
Fire Plume ◽  
Magnolia Grandiflora ◽  
Hydraulic Failure ◽  
Factors Influencing ◽  
Wide Range ◽  
Transport Path ◽  
Measured Water

Abstract The heat plume associated with fire has been hypothesized to cause sufficient water loss from trees to induce embolism and hydraulic failure. However, it is unclear whether the water transport path remains sufficiently intact during scorching or burning of foliage to sustain high water loss. We measured water uptake by branches of Magnolia grandiflora while exposing them to a range of fire intensities, and examined factors influencing continued water uptake after fire. Burning caused a 22-fold mean increase in water uptake, with greatest rates of water loss observed at burn intensities that caused complete consumption of leaves. Such rapid uptake is possible only with steep gradients in water potential, which would likely result in substantial cavitation of xylem and loss of conductivity in intact stems. Water uptake continued after burning was complete, and was greatest following burn intensities that killed leaves but did not consume them. This post-fire uptake was mostly driven by rehydration of the remaining tissues, rather than evaporation from the tissues. Our results indicate that the fire-plume hypothesis can be expanded to include a wide range of burning conditions experienced by plants. High rates of water loss are sustained during burning, even when leaves are killed or completely consumed.

Processing polymer nanocomposites with natural additives for medical applications

2019 ◽  
Vol 39 (2) ◽  
pp. 178-185
Author(s):  
Demet Topaloğlu Yazıcı ◽  
Arzu Yener
Keyword(s):  
Olive Oil ◽  
Polymer Nanocomposites ◽  
Water Uptake ◽  
High Water ◽  
Medical Applications ◽  
Drug Adsorption ◽  
Hydrophobizing Agent ◽  
Images Processing ◽  
Natural Additive ◽  
Natural Additives

Abstract The aim of this study is to analyze the effect of natural additive incorporation on processing nanocomposites and their effect on the functional characteristics of nanocomposites such as water uptake characteristics, drug adsorption and dissolution behaviors. Chitosan and montmorillonite were processed with olive oil and glycerin natural additives. In order to compare the processing results, the structure and the morphology of the polymer nanocomposites were examined by using infrared spectra, X-ray diffractograms and electron microscope images. Processing with nontoxic and healthful olive oil as a hydrophobizing agent overcame the high water uptake properties of the polymer nanocomposites and eliminated the use of other expensive chemicals. The nanocomposites without additives adsorbed the highest amounts of methylene blue at equilibrium. In vitamin B12 dissolution studies, not only the additives but also the reinforcement affected the results. Obviously, it can be seen that both the natural additive types and the reinforcement modification effects governed the drug adsorption and dissolution behaviors of the new tailored polymer nanocomposites. Moreover, the additives also improved the processing and handling abilities of these polymer nanocomposites. According to the results, these nanocomposites are promising candidates for medical applications like as a carrier for drug delivery and for skin treatment studies.

Influence of Citric Acid and Curing Time on Water Uptake

2014 ◽  
Vol 625 ◽  
pp. 123-126 ◽  
Author(s):  
Sohibatul Muizzah Mohamad Izhar ◽  
Ku Zilati Ku Shaari ◽  
Zakaria Man ◽  
Yon Norasyikin Samsudin
Keyword(s):  
Citric Acid ◽  
Water Uptake ◽  
Barrier Properties ◽  
High Water ◽  
Cross Linking ◽  
Curing Time ◽  
Gas Barrier ◽  
Water Sensitivity ◽  
Hydrophilic Character ◽  
Starch Films

Starch is highly promising biopolymer for the production of packaging material since it gives films a good tensile and gas barrier properties. However, non-plasticized starch films are brittle and their hydrophilic character results in poor moisture barrier properties and high water sensitivity. In order to improve films formation and material properties of starch, plasticization and chemical modification such as cross-linking of the starch is required. The cross-linking reaction able to improve thermal stability, tensile strength and decreased the dissolution of starch films in water and formic acid. From the study, the percentage of water uptake reduced when the blending ratio of citric acid increased.The percentage of water uptake highly affected by curing time compared to blending ratio. Increasing the curing time from 1 hour to 2 hour significantly reduced the percentage of water uptake. At 4 hour curing time, the percentage water uptake reached equilibrium faster than 3 hour curing time. This shows that more citric acid molecules were chemically bonded with the starch chains, resulting in higher cross link degree and thus, reduced the percentage of water uptake.

scholarly journals Chitosan/Polycyclodextrin (CHT/PCD)-Based Sponges Delivering VEGF to Enhance Angiogenesis for Bone Regeneration

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 784
Author(s):  
Carla Palomino-Durand ◽  
Marco Lopez ◽  
Pierre Marchandise ◽  
Bernard Martel ◽  
Nicolas Blanchemain ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Water Uptake ◽  
Average Pore Size ◽  
High Water ◽  
Growth Factor Delivery ◽  
Average Pore ◽  
Polyelectrolyte Complexes ◽  
Migration Effect ◽  
Angiogenic Effect

Vascularization is one of the main challenges in bone tissue engineering (BTE). In this study, vascular endothelial growth factor (VEGF), known for its angiogenic effect, was delivered by our developed sponge, derived from a polyelectrolyte complexes hydrogel between chitosan (CHT) and anionic cyclodextrin polymer (PCD). This sponge, as a scaffold for growth factor delivery, was formed by freeze-drying a homogeneous CHT/PCD hydrogel, and thereafter stabilized by a thermal treatment. Microstructure, water-uptake, biodegradation, mechanical properties, and cytocompatibility of sponges were assessed. VEGF-delivery following incubation in medium was then evaluated by monitoring the VEGF-release profile and its bioactivity. CHT/PCD sponge showed a porous (open porosity of 87.5%) interconnected microstructure with pores of different sizes (an average pore size of 153 μm), a slow biodegradation (12% till 21 days), a high water-uptake capacity (~600% in 2 h), an elastic property under compression (elastic modulus of compression 256 ± 4 kPa), and a good cytocompatibility in contact with osteoblast and endothelial cells. The kinetic release of VEGF was found to exert a pro-proliferation and a pro-migration effect on endothelial cells, which are two important processes during scaffold vascularization. Hence, CHT/PCD sponges were promising vehicles for the delivery of growth factors in BTE.

Development of functionalized nanocrystalline cellulose-based polyelectrolytes with high water uptake

2021 ◽  
Author(s):  
Mohammad Motiur Rahman ◽  
Abu Hasan Howlader ◽  
Ehsanur Rahman ◽  
Hridoy Roy ◽  
Mohammad Mozammal Hosen ◽  
...  
Keyword(s):  
Water Uptake ◽  
High Water ◽  
Nanocrystalline Cellulose

Use of Hemp Fibres in 3D Printed Concrete

2022 ◽  
Author(s):  
Naomi Zahra van Hierden ◽  
Florent Gauvin ◽  
S.S. Lucas ◽  
T.A.M. Salet ◽  
Henricus Jozef Hubertus Brouwers
Keyword(s):  
Water Uptake ◽  
High Water ◽  
Tensile Tests ◽  
Laboratory Scale ◽  
Natural Fibres ◽  
Hemp Fibres ◽  
Fresh State ◽  
Concrete Mechanical Properties ◽  
3D Printed ◽  
Direct Tensile

The use of fibres as reinforcement of 3D printed concrete is widely known and applicable in many situations. However, most of the applied fibres are not produced from renewable resources. Natural fibres are commonly considered as an ecological alternative for these fibres. In order to contribute to improvement of the sustainability of 3D printed concrete, natural fibres such as hemp can replace these synthetic fibres. The objective of this study is therefore to study the possibilities of adding hemp fibres for 3D printing purposes. Due to the comparable properties of hemp and synthetic fibres, natural fibres tend to be suitable for printing purposes. Mixes are made at laboratory scale using batches of 1 – 3 kg. The study examines the effect of adding hemp fibres for the mechanical and fresh state properties of hemp-based concrete. Mechanical properties from bending tests and direct tensile tests show comparable properties of mortars containing hemp fibres and mortars containing synthetic fibres. The fresh state behaviour of the designed concrete mix showed promising and comparable results for a mix based on 0.5wt% of hemp fibres. One of the major issues regarding the use of natural fibres is the irregularity and high water uptake of the fibres. Due to its high hydrophilicity natural hemp fibres take up much water and can therefore degrade. For this study the effect of water uptake did not have much influence on the mixing and printing purposes. By printing a wall element on laboratory scale the use of hemp fibre-reinforced 3D concrete is validated.

Preparation of Cation Exchanger Using Electrospun Polystyrene Nanofiber

2006 ◽  
Vol 10 (2) ◽  
pp. 196-200 ◽  
Author(s):  
Hyung-Hwan An ◽  
◽  
Changyun Shin ◽  
Keyword(s):  
Ion Exchange ◽  
Glass Fiber ◽  
Water Uptake ◽  
Cation Exchanger ◽  
Fiber Surface ◽  
High Water ◽  
Exchange Capacity ◽  
Experimental Results ◽  
Ion Exchanger ◽  
Ion Exchange Capacity

We studied a new ion exchanger for high ion exchange capacity (IEC) and rapid ion exchange. Polystyrene nanofiber ion exchangers (PSNIEs) were prepared by electrospinning from solutions of dissolved polystyrene followed by sulfonation. Coating and sulfonation were used to modify the glass fiber surface with polystyrene to produce cation exchanger fiber (CEF). We present new experimental results on the performance of PSNIE and CEF related to parameters of IEC, water uptake, and surface morpoholgy. IEC and water uptake of PSNIE depend on sulfonation time. IEC reached 3.74 mmol/g at relatively high water uptake of 0.6 to 0.77g H2O/g-dry-PNIE. IEC and water uptake of CEF reached 3.61mmol/g-CEF and 0.25g H2O/g-dry-CEF.

scholarly journals A zeolite-like aluminophosphate membrane with molecular-sieving property for water desalination

2018 ◽  
Vol 9 (9) ◽  
pp. 2533-2539 ◽  
Author(s):  
Yanju Wang ◽  
Xiaoqin Zou ◽  
Lei Sun ◽  
Huazhen Rong ◽  
Guangshan Zhu
Keyword(s):  
Water Uptake ◽  
Water Flux ◽  
High Water ◽  
Water Desalination ◽  
Membrane Material ◽  
Ion Rejection ◽  
Molecular Sieving

A fascinating membrane material composed of polycrystalline zeolite-like aluminophosphate with narrow pore and high water uptake is well developed, which exhibits superior desalination performance in terms of excellent ion rejection and record water flux.

scholarly journals Water and methanol adsorption on MOFs for cycling heat transformation processes

2014 ◽  
Vol 38 (5) ◽  
pp. 1846-1852 ◽  
Author(s):  
Felix Jeremias ◽  
Dominik Fröhlich ◽  
Christoph Janiak ◽  
Stefan K. Henninger
Keyword(s):  
Low Temperature ◽  
Water Uptake ◽  
High Water ◽  
Heat Pumps ◽  
Uptake Capacity ◽  
Water Uptake Capacity ◽  
Temperature Heat ◽  
Thermally Driven ◽  
Heat Transformation ◽  
Transformation Processes

MOFs with high water uptake capacity and hydrothermal stability are gaining attention for low temperature heat transformation applications such as thermally driven adsorption chillers or adsorption heat pumps.

Synthesis of composite material HKUST-1/LiCl with high water uptake for water extraction from atmospheric air

2020 ◽  
Vol 511 ◽  
pp. 119842
Author(s):  
Huizhong Zhao ◽  
Min Lei ◽  
Tao Liu ◽  
Tianhou Huang ◽  
Min Zhang
Keyword(s):  
Composite Material ◽  
Water Uptake ◽  
High Water ◽  
Water Extraction ◽  
Atmospheric Air
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