scholarly journals Encapsulate α-MnO2 nanofiber within graphene layer to tune surface electronic structure for efficient ozone decomposition

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guoxiang Zhu ◽  
Wei Zhu ◽  
Yang Lou ◽  
Jun Ma ◽  
Wenqing Yao ◽  
...  
Keyword(s):  
Graphene Layer ◽  
Water Resistance ◽  
Catalyst Design ◽  
Ozone Decomposition ◽  
Oxygen Species ◽  
Ozone Molecule ◽  
Practical Application ◽  
Surface Electronic Structure ◽  
Reaction Barriers ◽  
Excellent Stability

AbstractMajor challenges encountered when developing manganese-based materials for ozone decomposition are related to the low stability and water inactivation. To solve these problems, a hierarchical structure consisted of graphene encapsulating α-MnO2 nanofiber was developed. The optimized catalyst exhibited a stable ozone conversion efficiency of 80% and excellent stability over 100 h under a relative humidity (RH) of 20%. Even though the RH increased to 50%, the ozone conversion also reached 70%, well beyond the performance of α-MnO2 nanofiber. Here, surface graphite carbon was activated by capturing the electron from inner unsaturated Mn atoms. The excellent stability originated from the moderate local work function, which compromised the reaction barriers in the adsorption of ozone molecule and the desorption of the intermediate oxygen species. The hydrophobic graphene shells hindered the chemisorption of water vapour, consequently enhanced its water resistance. This work offered insights for catalyst design and would promote the practical application of manganese-based catalysts in ozone decomposition.

scholarly journals Allyl glycidyl ether-modified animal glue binder for improved water resistance and bonding strength in sand casting

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Chen-chen Fan ◽  
Qian Tang
Keyword(s):  
Tensile Strength ◽  
Bonding Strength ◽  
Room Temperature ◽  
Water Resistance ◽  
Glycidyl Ether ◽  
Animal Glue ◽  
Practical Application ◽  
Foundry Industry ◽  
Dog Bone ◽  
Allyl Glycidyl Ether

This paper aims to develop a modified animal glue sand binder for foundry casting with improved water resistance and bonding strength. An efficient method is reported by using sodium hydroxide as the catalyst to improve the operability of animal glue binder and allyl glycidyl ether as the modifier to improve the water resistance and bonding strength. Sand specimens prepared using allyl glycidyl ether-modified animal glue binder were cured by compressed air at room temperature. The proposed method saves energy and is environmentally friendly and inexpensive. Compared with unmodified animal glue binder, standard dog bone sand specimens with allyl glycidyl ether-modified animal glue binder had higher tensile strength of 2.58 MPa, flowability of 1.95 g, better water resistance (a lower decrease in tensile strength at 25 °C and relative humidity of 60%), and good collapsibility. This allyl glycidyl ether-modified animal glue binder is suitable for practical application in the foundry industry.

scholarly journals The Effect of the Surface Energy of Water Glass on the Fluidity of Sand

2020 ◽  
Vol 58 (5) ◽  
pp. 319-325
Author(s):  
Min A Bae ◽  
Man Sig Lee ◽  
Jae Ho Baek
Keyword(s):  
Surface Tension ◽  
Water Glass ◽  
Water Resistance ◽  
Environmental Issues ◽  
Environmental Standards ◽  
Practical Application ◽  
Inorganic Binder ◽  
Flow Test ◽  
Silicate Chemistry ◽  
Casting Industry

In recent years, the metal casting industry has sought to meet ever more stringent environmental standards. Inorganic binders based on silicate chemistry have many advantages with respect to environmental issues, but often suffer from reduced strength, burn-on and poor water-resistance. In particular, when sand is mixed with a water glass based inorganic binder, it adversely affects fluidity. In this study, a Powder flow test (PFT) analysis was conducted to confirm the effect of the surface tension of water glass on mixed sand. Certain additives were selected as surfactants to lower the surface tension of the water glass. The characteristics of the samples were measured using the PFT. A correlation between the surface tension of the water glass and the fluidity of the mixed sand was established. We then evaluated the effect of the inorganic binder on core strength. Using the surfactants, the fluidity of the mixed sand increased by 66%. However, strength and water resistance were reduced by approximately 45%. As a result, it was found that when 1.5% of surfactant was added, the resulting fluidity and humidity strength characteristics produced a mixed sand with good properties. Water glass with improved fluidity can produce a high quality core and mold. Finally, we used a practical application prove that an inorganic binder can replace organic binders in foundry cores.

scholarly journals Study of "Saralsk" Deposit for Practical Applications in Construction

2021 ◽  
Vol 1 (1) ◽  
pp. 3-6
Author(s):  
Avetik Artavazd Arzumanyan ◽  
Vardan Grigor Tadevosyan ◽  
Nelli Gagik Muradyan ◽  
Hovhannes Vachagan Navasardyan
Keyword(s):  
Microscopic Study ◽  
Frost Resistance ◽  
Water Resistance ◽  
Structural Features ◽  
Practical Application ◽  
Petrographic Composition ◽  
Secondary Minerals ◽  
Practical Applications ◽  
Stone Materials ◽  
Technical Properties

In article the results of research of structural features and technical properties of andesite - basalt stone rock of the “Saralsk” deposit are given. The material is estimated by its mineral - petrographic composition, and the cuts/refinements of stone materials have been made for the microscopic study of mineral-petrographic composition. Researches are conducted according to requirements of acting standards and as a result, it became clear, that the rock consists basically of minerals opacitized hornblende and plagioclase, it doesn't contain any no secondary minerals such as hydroxides of iron, chlorites, epidote, quartz, saricite, etc. Petrographic researches have allowed to determine the species of stone rock. The density, strength, water resistance and frost resistance of stone rock are studied. The suitability of the material for practical application in construction, including for external works, is revealed.

scholarly journals Sol-Gel Nir-Reflective Multilayer Coatings On Glass Through Uvpolymerizable Ceramic Nanoparticles

1999 ◽  
Vol 576 ◽  
Author(s):  
M. Mennig ◽  
P. W. Oliveira ◽  
H. Schmidt
Keyword(s):  
Sol Gel ◽  
Uv Curing ◽  
Dip Coating ◽  
Float Glass ◽  
Multilayer Coatings ◽  
Practical Application ◽  
Fixed Angle ◽  
Visible Transmittance ◽  
Preparation Route ◽  
Excellent Stability

ABSTRACTA new preparation route for an dielectric NIR-reflexion filter on glass is described. Coating sols are synthesized from SiO2 and TiO2 nanoparticles with photopolymerizable surface ligands. A 5-layer stack consisting of 2 SiO2 and 3 TiO2 layers was deposited on float glass by angledependent dip-coating (ADDC) with a fixed angle of 4° to the vertical and subsequent UV-curing. Finally, the whole stack was densified at 450 °C without cracking or discolouring. UV-vis-NIR transmittance and reflectance spectra show a steep increase of reflectance at 750 nm. In the range between 800 nm and 1200 nm, the reflectance is > 80 %. The visible transmittance is about 72 % due to single reflexion peaks. The bandwidth of the NIR reflection filter prepared by ADDC is about 200 nm larger and its maximum reflectance is only 5 % smaller compared to vertical dip-coating. The interference layer stack shows excellent stability in Taber Abraser, rubber, saline and UV tests, indicating a high potential for practical application.

Enhanced Antibacterial Photocatalytic Activity of Porous Few-Layer C3N4

2020 ◽  
Vol 20 (9) ◽  
pp. 5944-5950 ◽  
Author(s):  
Guoxin Song ◽  
Longwei Wang ◽  
Ruiqi Yang ◽  
Yanchen Ji ◽  
Ruitong Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Hydroxyl Radicals ◽  
Removal Rate ◽  
Low Cost ◽  
Disinfection Byproducts ◽  
Oxygen Species ◽  
Positive Bacterium ◽  
Surface Areas ◽  
Good Biocompatibility ◽  
Excellent Stability

Nowadays, antibacterial photocatalytic activity of semiconductors has attracted great attention due to its excellent stability, good biocompatibility and no disinfection byproducts. Herein, a porous few-layer C3N4 was successfully fabricated via a simple and low-cost bottom-up method. The asprepared porous few-layer C3N4 exhibits large specific surface areas, which is about 4.8 times than bulk C3N4. Under the light (<430 nm) irradiation, reactive oxygen species (ROS) (singlet oxygen (1O2), hydroxyl radicals (·OH), and superoxide (O·−2)) can be generated. The porous few-layer C3N4 was used as an antibacterial agent to kill gram-positive bacterium S. Aureus with an anibacterial efficiency up to 99.7%. The log removal rate of the porous few-layer C3N4 is more than 50 times than the bulk C3N4. The material shows a potential application in water purification and antibacterial photocatalytic therapy.

Biopolymer Thin Films for Photonics Applications

2009 ◽  
Vol 415 ◽  
pp. 33-36 ◽  
Author(s):  
Roxana Popescu ◽  
Mirela Moldoveanu ◽  
Ileana Rău
Keyword(s):  
Optical Switching ◽  
Meat Industry ◽  
Practical Application ◽  
Main Interest ◽  
Operation Temperature ◽  
Electro Optic ◽  
All Optical ◽  
Photo Stability ◽  
All Optical Switching ◽  
Excellent Stability

In this paper we focused our studies on functionalization of DNA and of collagen with active molecules and thin film processing, their photostability in view of their further application in electronics and photonics as all optical switching elements, bioleds, optical memories, light amplifies, electro-optic modulators, etc. We have also addressed very important point for the practical application of these materials, not studied previously, which is the photo stability of these materials. If they have to work in photonic systems they have to exhibit an excellent stability in time and at the operation temperature range. The main interest for biopolymers arises from the fact that they are renewable, derived from waste of meat industry and they are biodegradable materials.

scholarly journals Evaluation of Water Resistance and Diffusion Properties of Paint Materials

10.14311/188 ◽  
2001 ◽  
Vol 41 (1) ◽  
Author(s):  
J. Drchalová ◽  
J. Poděbradská ◽  
J. Maděra ◽  
R. Černý
Keyword(s):  
Water Resistance ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Practical Application ◽  
Simple Method ◽  
Basic Lining ◽  
And Diffusion ◽  
Effective Water ◽  
Diffusion Properties

A simple method is presented for evaluating the water-proofness quality of paints on lining materials. The method is based on measuring the integral capillarity in dependence on time, and then comparing this value to the value determined for the basic lining material. Measurements of the effective water vapor permeability then provide information on the risk of condensation which may increase after applying the paint. A practical application of the method is performed with four Karlocolor paints on glass concrete substrates. All the Karlocolor paints are found to be very effective materials for driven rain protection. The diffusion properties of all the paints are found to be excellent.

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