scholarly journals Superhydrophobic Sands for the Preservation and Purification of Water

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 151
Author(s):  
Yuyang Liu ◽  
Chang-Hwan Choi
Keyword(s):  
Water Surface ◽  
Particulate Material ◽  
Self Assembled Monolayer ◽  
Hydrophobic Coatings ◽  
Hydrophobic Coating ◽  
Evaporation Loss ◽  
Zno Nanocrystals ◽  
Sand Particles ◽  
Purification Of Water ◽  
Nanoscale Roughness

Sand, a cheap and naturally abundant particulate material, was modified with photocatalytic and hydrophobic coatings to reduce evaporation loss and facilitate the purification of water. The first-level photocatalytic coatings (TiO2 or ZnO nanocrystals) rendered nanoscale roughness on the surface of the sand. The additional second-level hydrophobic coating of a self-assembled monolayer of octyltrimethoxysilane (OTS) made the sand particles superhydrophobic because of the nanoscale roughness imposed by the nanocrystals. The superhydrophobic sand particles, floating on the free surface of water due to their superhydrophobicity, significantly reduced the evaporation loss of water by 60%–90% in comparison to an uncovered water surface. When the outer hydrophobic coatings are weathered or disengaged, the inner photocatalytic coatings become exposed to water. Then, the sand particles act as photocatalysts to degrade the contaminants in water under solar radiation.

scholarly journals Ultra-thin self-healing vitrimer coatings for durable hydrophobicity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingcheng Ma ◽  
Laura E. Porath ◽  
Md Farhadul Haque ◽  
Soumyadip Sett ◽  
Kazi Fazle Rabbi ◽  
...  
Keyword(s):  
Thin Film ◽  
Dip Coating ◽  
Self Healing ◽  
Hydrophobic Coatings ◽  
Hydrophobic Coating ◽  
Perfluorinated Compound ◽  
Hydrophobic Materials ◽  
The Matrix ◽  
Coating Durability ◽  
Protective Structures

AbstractDurable hydrophobic materials have attracted considerable interest in the last century. Currently, the most popular strategy to achieve hydrophobic coating durability is through the combination of a perfluoro-compound with a mechanically robust matrix to form a composite for coating protection. The matrix structure is typically large (thicker than 10 μm), difficult to scale to arbitrary materials, and incompatible with applications requiring nanoscale thickness such as heat transfer, water harvesting, and desalination. Here, we demonstrate durable hydrophobicity and superhydrophobicity with nanoscale-thick, perfluorinated compound-free polydimethylsiloxane vitrimers that are self-healing due to the exchange of network strands. The polydimethylsiloxane vitrimer thin film maintains excellent hydrophobicity and optical transparency after scratching, cutting, and indenting. We show that the polydimethylsiloxane vitrimer thin film can be deposited through scalable dip-coating on a variety of substrates. In contrast to previous work achieving thick durable hydrophobic coatings by passively stacking protective structures, this work presents a pathway to achieving ultra-thin (thinner than 100 nm) durable hydrophobic films.

scholarly journals DESIGN, CONSTRUCTION AND EVALUATION OF RUNOFF WATER HARVESTING POND FOR SMALLHOLDER FARMING

2021 ◽  
Vol 9 (9) ◽  
pp. 30-39
Author(s):  
Bayan Ahmed ◽  
Fikadu Gemeda
Keyword(s):  
Water Surface ◽  
Water Requirement ◽  
Crop Water Requirement ◽  
Water Harvesting ◽  
Crop Water ◽  
Runoff Water ◽  
Evaporation Loss ◽  
Run Off ◽  
Supplementary Irrigation ◽  
Design Construction

Rainfall shortage and variability constrain crop production of smallholder farmers in Ethiopia is the main problem.  For this supplementary irrigation by run off harvesting is strategic pathway to reduce poverty in rural drought prone areas for enhancing agricultural productivity and boosting farm income. For this, this study is conducted to Design, construction and evaluation of runoff water harvesting Pond for supplementary irrigation to addressing inherent crop failures under the rain fed agriculture due to mainly erratic rainfall. For this design climatic and soil data were input to determine seasonal crop water requirement (CWR) of onion and evaporation loss of water from water surface. Then the performances of water harvested verses area irrigate were evaluated. To make this study more economical the water harvester capacity decreed by two fold and water harvesting made at two times. Seasonal volume crop water requirement (CWR) of onion for farm area 2500 m2 and evaporation loss of water from water surface of 121 m2 and total volume of seasonal water need were   382.05,53.38 and 435.43 m3  respectively. The geo-membrane laminated water harvester that has capacity of 223 m3 was designed and constructed. From on field performance shows, this volume of water harvested twice can irrigate 0.25ha by supplementary irrigation using water saving irrigation technology (treadle pump) by over showering and was produced 4.2 tone/ha. The investment, operation and production costs were 63116, 1125 and 6675 ETH birr respectively.  The total cost was 70,916 birr and The growth return of 0.25ha was 15,750 birr/year (1050kg*15 birr/kg). This show the farmer can return 22.21% of their investment cost. So it is recommended to the government and non-government to initiate the farmers at lower stream of the catchment to harvest run off water and use for supplementary irrigation to increase their income.

scholarly journals Sustainable, Fluorine-Free, Low Cost and Easily Processable Materials for Hydrophobic Coatings on Flexible Plastic Substrates

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2234
Author(s):  
Carmela T. Prontera ◽  
Giuliano Sico ◽  
Maria Montanino ◽  
Anna De Girolamo Del Mauro ◽  
Paolo Tassini ◽  
...  
Keyword(s):  
Stearic Acid ◽  
Low Cost ◽  
Barrier Properties ◽  
Functional Coatings ◽  
Water Contact ◽  
Hydrophobic Coatings ◽  
Plastic Substrates ◽  
Hydrophobic Coating ◽  
Green Approach ◽  
Moisture Barrier Property

Zinc oxide nanoparticles (ZnONPs) and stearic acid are herein used for the preparation of hydrophobic coatings with good moisture barrier property on flexible plastic substrates. Fast, high throughput, mild and easy-to-run processing techniques, like airbrushing and gravure printing, are applied for thin films deposition of these materials. The results of this study indicated that the best hydrophobic coating in terms of water contact angle (115°) is obtained through a two-steps printing deposition of a ZnONPs layer followed by a stearic acid layer. All the deposition procedures proved to be effective in terms of water vapor barrier properties, reaching values of 0.89 g/m2/day, with a 45% reduction with respect to the bare substrate. These preliminary data are very encouraging in the perspective of a low cost and green approach for the realization of functional coatings for packaging applications.

scholarly journals UV-LED as a New Emerging Tool for Curable Polyurethane Acrylate Hydrophobic Coating

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 487
Author(s):  
Siti Khairunisah Ghazali ◽  
Nadia Adrus ◽  
Rohah A. Majid ◽  
Fathilah Ali ◽  
Jamarosliza Jamaluddin
Keyword(s):  
Light Emitting Diode ◽  
Urethane Acrylate ◽  
Water Contact ◽  
Promising Alternative ◽  
Light Emitting ◽  
Hydrophobic Coatings ◽  
Hydrophobic Coating ◽  
Uv Led ◽  
A New Technique ◽  
High Degree

The elimination of mercury, low energy consumption, and low heat make the ultraviolet light-emitting diode (UV-LED) system emerge as a promising alternative to conventional UV-mercury radiation coating. Hence, a series of hydrophobic coatings based on urethane acrylate oligomer and fluorinated monomer via UV-LED photopolymerisation was designed in this paper. The presence of fluorine component at 1160 cm−1, 1235 cm−1, and 1296 cm−1 was confirmed by Fourier Transform Infra-Red spectroscopy. A considerably high degree C=C conversion (96–98%) and gel fraction (95–93%) verified the application of UV-LED as a new technique in radiation coating. It is well-accepted that fluorinated monomer can change the surface wettability as the water contact angle of the coating evolved from 88.4° to 121.2°, which, in turn, reduced its surface free energy by 70.5%. Hence, the hydrophobicity of the coating was governed by the migration of the fluorine component to the coating surface as validated by scanning electron and atomic force microscopies. However, above 4 phr of fluorinated monomer, the transparency of the cured coating examined by UV-visible spectroscopy experienced approximately a 16% reduction. In summary, the utilisation of UV-LED was a great initiative to develop green aspect in photopolymerisation, particularly in coating technology.

scholarly journals Robust Super-Hydrophobic Coating Prepared by Electrochemical Surface Engineering for Corrosion Protection

Coatings ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 452 ◽  
Author(s):  
Bi ◽  
Li ◽  
Zhao ◽  
Ran ◽  
Cao ◽  
...  
Keyword(s):  
Corrosion Protection ◽  
Surface Engineering ◽  
Electrochemical Etching ◽  
Electrochemical Anodization ◽  
Protection Mechanism ◽  
Hydrophobic Coatings ◽  
Wetting Properties ◽  
Hydrophobic Coating ◽  
Micro Arc Oxidation ◽  
Engineering Materials

Corrosion—reactions occuring between engineering materials and their environment—can cause material failure and catastrophic accidents, which have a serious impact on economic development and social stability. Recently, super-hydrophobic coatings have received much attention due to their effectiveness in preventing engineering materials from further corrosion. In this paper, basic principles of wetting properties and corrosion protection mechanism of super-hydrophobic coatings are introduced firstly. Secondly, the fabrication methods by electrochemical surface engineering—including electrochemical anodization, micro-arc oxidation, electrochemical etching, and deposition—are presented. Finally, the stabilities and future directions of super-hydrophobic coatings are discussed in order to promote the movement of such coatings into real-world applications. The objective of this review is to bring a brief overview of the recent progress in the fabrication of super-hydrophobic coatings by electrochemical surface methods for corrosion protection of engineering materials.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

In situ microprobe quantitation of inorganic particle burden in paraffin sections of lung tissue

1988 ◽  
Vol 46 ◽  
pp. 990-991
Author(s):  
Jerrold L. Abraham
Keyword(s):  
Lung Tissue ◽  
Quantitative Information ◽  
Particulate Material ◽  
Paraffin Sections ◽  
Tissue Samples ◽  
Qualitative And Quantitative ◽  
The Past ◽  
Quantitative Analyses ◽  
Data Result

Inorganic particulate material of diverse types is present in the ambient and occupational environment, and exposure to such materials is a well recognized cause of some lung disease. To investigate the interaction of inhaled inorganic particulates with the lung it is necessary to obtain quantitative information on the particulate burden of lung tissue in a wide variety of situations. The vast majority of diagnostic and experimental tissue samples (biopsies and autopsies) are fixed with formaldehyde solutions, dehydrated with organic solvents and embedded in paraffin wax. Over the past 16 years, I have attempted to obtain maximal analytical use of such tissue with minimal preparative steps. Unique diagnostic and research data result from both qualitative and quantitative analyses of sections. Most of the data has been related to inhaled inorganic particulates in lungs, but the basic methods are applicable to any tissues. The preparations are primarily designed for SEM use, but they are stable for storage and transport to other laboratories and several other instruments (e.g., for SIMS techniques).

Chemical Classification and Particle Sizing of Foundry Sands

1985 ◽  
Vol 43 ◽  
pp. 388-389
Author(s):  
D.S. DeMiglio
Keyword(s):  
Image Analysis ◽  
Energy Dispersive Spectrometer ◽  
Image Analysis System ◽  
Representative Sampling ◽  
Foundry Sands ◽  
Large Atomic Number ◽  
Backscattered Electron ◽  
Sand Particles ◽  
Analysis System ◽  
Reclamation System

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.

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