scholarly journals Preparation of a solid product with high water content and water retention properties

2020 ◽  
Vol 22 (3) ◽  
pp. 17-23
Author(s):  
Marko Cvijić ◽  
Janvit Golob
Keyword(s):  
Mass Transfer ◽  
Phase Equilibrium ◽  
Water Content ◽  
Water Retention ◽  
High Water ◽  
High Water Content ◽  
Solid Product ◽  
Phase Rule ◽  
Solutions Of Equations ◽  
Water Retention Properties

AbstractThis work presents the development of a solid product with a high water content (99.08%) and water retention properties. Water was chosen as a potential carrier of a volatile active substance and water retaining properties of material were studied at a temperatures and relative air humidity values with the support of the theory of drying. The study first confirmed the role of Gibbs’ phase rule in the research of solid-gas phase equilibrium, and second presented drying kinetics developed from Fick’s second law and expressed with the first term of the Fourier equation. Solutions of equations for phase equilibrium and mass transfer enabled the calculation of Luikov’s parameters, which are important for equilibrium relations and for the diffusivity of water in a solid for mass transfer prediction. The obtained thermodynamic and kinetic parameters enabled product characterisation that may be important for the prediction of retention times.

Direct Carbon Fuel Cell With Molten Hydroxide Electrolyte

2004 ◽  
Author(s):  
Strahinja Zecevic ◽  
Edward M. Patton ◽  
Parviz Parhami
Keyword(s):  
Mass Transfer ◽  
Water Content ◽  
High Water ◽  
Electrode Spacing ◽  
High Water Content ◽  
Cell Design ◽  
Medium Temperature ◽  
Humid Atmosphere ◽  
Direct Carbon Fuel Cell ◽  
Carbonate Formation

Historically, despite its compelling cost and performance advantages, the use of molten hydroxide electrolytes has been ignored by DCFC researches, primarily due to the potential for formation of carbonate salt in the cell. This paper describes the electrochemistry of a patented medium-temperature DCFC based on molten hydroxide electrolyte, which overcomes the historical carbonate formation. An important technique discovered for significantly reducing carbonate formation is to ensure high water content of the electrolyte. Water helps hydrolysis of the carbonates and reduces formation of peroxide and superoxide ions that may react with carbon dioxide producing carbonate ions. High water content can be achieved by maintaining a humid atmosphere above the melt. To date, four successive generations of medium temperature DCFC prototypes have been built and tested at SARA Inc. to demonstrate the technology, all using graphite rods as their fuel source. The cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated delivering more than 40 A at 0.3 V with the current density exceeding 200 mA/cm2. The basic feature of this simple cell design is that the cathode is not traditional gas fed electrode type. It is a non-porous electrode structure made of an inexpensive Fe-Ti alloy and gaseous oxygen is introduced into the cell by bubbling humid air through the electrolyte. Results obtained indicated that the cell operation was under a mixed activation-Ohmic-mass transfer control. The activation control is mainly due to slow anode oxidation of carbon, the Ohmic control is mainly due to a large electrode spacing whereas the mass transfer control is most likely because of slow diffusion of oxygen species (O2, O22−, O2−, and H2O) to the cathode surface. Cell performances are improved in the new generation cell design, which has been recently built, and which enables faster mass transfer of the reaction species and a lower voltage drop across the electrolyte. In the new design, the cathode is a separate perforated component of the cell that allows the use of a larger surface area electrode and for the electrode spacing to be varied.

Phase equilibrium in a water + n-hexane system with a high water content

2017 ◽  
Vol 91 (2) ◽  
pp. 330-335 ◽  
Author(s):  
S. M. Rasulov ◽  
S. M. Orakova ◽  
Z. A. Isaev
Keyword(s):  
Phase Equilibrium ◽  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Hexane System

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Microwave-Induced Thermoacoustic Imaging for Embedded Explosives Detection in High-Water Content Medium

2019 ◽  
Vol 67 (7) ◽  
pp. 4803-4810 ◽  
Author(s):  
Xiong Wang ◽  
Tao Qin ◽  
Yexian Qin ◽  
Ahmed H. Abdelrahman ◽  
Russell S. Witte ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
Explosives Detection ◽  
High Water Content ◽  
Thermoacoustic Imaging

scholarly journals Deep mantle melting, global water circulation and its implications for the stability of the ocean mass

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Shun-ichiro Karato ◽  
Bijaya Karki ◽  
Jeffrey Park
Keyword(s):  
Phase Transformation ◽  
Water Content ◽  
Sea Level ◽  
High Water ◽  
Water Circulation ◽  
Mantle Melting ◽  
High Water Content ◽  
Mineral Physics ◽  
Deep Mantle ◽  
Global Water

AbstractOceans on Earth are present as a result of dynamic equilibrium between degassing and regassing through the interaction with Earth’s interior. We review mineral physics, geophysical, and geochemical studies related to the global water circulation and conclude that the water content has a peak in the mantle transition zone (MTZ) with a value of 0.1–1 wt% (with large regional variations). When water-rich MTZ materials are transported out of the MTZ, partial melting occurs. Vertical direction of melt migration is determined by the density contrast between the melts and coexisting minerals. Because a density change associated with a phase transformation occurs sharply for a solid but more gradually for a melt, melts formed above the phase transformation depth are generally heavier than solids, whereas melts formed below the transformation depth are lighter than solids. Consequently, hydrous melts formed either above or below the MTZ return to the MTZ, maintaining its high water content. However, the MTZ water content cannot increase without limit. The melt-solid density contrast above the 410 km depends on the temperature. In cooler regions, melting will occur only in the presence of very water-rich materials. Melts produced in these regions have high water content and hence can be buoyant above the 410 km, removing water from the MTZ. Consequently, cooler regions of melting act as a water valve to maintain the water content of the MTZ near its threshold level (~ 0.1–1.0 wt%). Mass-balance considerations explain the observed near-constant sea-level despite large fluctuations over Earth history. Observations suggesting deep-mantle melting are reviewed including the presence of low-velocity anomalies just above and below the MTZ and geochemical evidence for hydrous melts formed in the MTZ. However, the interpretation of long-term sea-level change and the role of deep mantle melting in the global water circulation are non-unique and alternative models are reviewed. Possible future directions of studies on the global water circulation are proposed including geodynamic modeling, mineral physics and observational studies, and studies integrating results from different disciplines.

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