Antibacterial Efficiency of Stainless-Steel Grids Coated with Cu-Ag by Thermionic Vacuum Arc Method

Autonomous smart natural ventilation systems (SVS) attached to the glass façade of living quarters and office buildings can help reducing the carbon footprint of city buildings in the future, especially during warm seasons and can represent an alternative to the conventional mechanical ventilation systems. The work performed in this manuscript focuses on the investigation of bacteria trapping and killing efficiency of stainless steel grids coated with a mixed layer of Cu-Ag. These grids are to be employed as decontamination filters for a smart natural ventilation prototype that we are currently building in our laboratory. The tested grids were coated with a mixed Cu-Ag layer using thermionic vacuum arc plasma processing technology. The fixed deposition geometry allowed the variation of Cu and Ag atomic concentration in coated layers as a function of substrate position in relation to plasma sources. The test conducted with air contaminated with a pathogen strain of staphylococcus aureus indicated that the filtering efficiency is influenced by two parameters: the pore size dimension and the coating layer composition. The results show that the highest filtering efficiency of 100% was obtained for fine pore (0.5 × 0.5 mm) grids coated with a mixed metallic layer composed of 65 at% Cu and 35 at% Ag. The second test performed only on reference grids and Cu-Ag (65–35 at%) under working conditions, confirm a similar filtering efficiency for the relevant microbiological markers. This particular sample was investigated from morphological, structural, and compositional point of view. The results show that the layer has a high surface roughness with good wear resistance and adhesion to the substrate. The depth profiles presented a uniform composition of Cu and Ag in the layer with small variations caused by changes in deposition rates during the coating process. Identification of the two metallic phases of the Cu and Ag in the layers evidences their crystalline nature. The calculated grain size of the nanocrystalline was in the range 14–21 nm.

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LESCALLOY 15-5 VAC-ARC

Alloy Digest ◽

10.31399/asm.ad.ss0522 ◽

1991 ◽

Vol 40 (8) ◽

Keyword(s):

Stainless Steel ◽

Precipitation Hardening ◽

Martensitic Stainless Steel ◽

Heat Treating ◽

Gas Content ◽

Vacuum Arc ◽

Steel Company ◽

Delta Ferrite ◽

Clean Steel ◽

Vacuum Arc Remelting

Abstract LESCALLOY 15-5 VAC-ARC is a precipitation hardening martensitic stainless steel with minimal delta ferrite. Vacuum arc remelting in the production of the alloy provides a low gas content, clean steel with optimum transverse properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-522. Producer or source: Latrobe Steel Company.

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AL 15-7 PRECIPITATION HARDENING ALLOY

Alloy Digest ◽

10.31399/asm.ad.ss0496 ◽

1988 ◽

Vol 37 (6) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

High Temperature ◽

Austenitic Stainless Steel ◽

Physical Properties ◽

Precipitation Hardening ◽

High Strength ◽

Heat Treating ◽

Vacuum Arc ◽

Temperature Performance

Abstract Allegheny Ludlum AL 15-7 Alloy is a chromium-nickel-molybdenum-aluminum semi-austenitic stainless steel. It is heat treatable to high strength and it has a moderate level of corrosion resistance. It is available both as a conventionally melted product and as vacuum arc or electroslag refined material. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-496. Producer or source: Allegheny Ludlum Corporation.

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BIODUR 316LS

Alloy Digest ◽

10.31399/asm.ad.ss0596 ◽

1995 ◽

Vol 44 (6) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Physical Properties ◽

Tensile Properties ◽

316L Stainless Steel ◽

Heat Treating ◽

Vacuum Arc ◽

Improve Corrosion Resistance ◽

Type 316L ◽

Type 316L Stainless Steel

Abstract BioDur 316LS stainless steel is a modified version of Type 316L stainless steel to improve corrosion resistance for surgical implant applications. The alloy is vacuum arc remelted. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-596. Producer or source: Carpenter.

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FINKL 420M PREMIUM QUALITY

Alloy Digest ◽

10.31399/asm.ad.ss0707 ◽

1998 ◽

Vol 47 (2) ◽

Keyword(s):

Stainless Steel ◽

Physical Properties ◽

Heat Treating ◽

Vacuum Arc ◽

Vacuum Arc Remelting ◽

Aisi 420

Abstract Finkl 420 Premium Quality stainless steel is a modification of AISI 420 with vacuum arc degassing and vacuum arc remelting. The modification results in a refined structure yielding cleanliness, strength, and isotropic properties. This datasheet provides information on composition, physical properties, and hardness. It also includes information on heat treating. Filing Code: SS-707. Producer or source: A. Finkl & Sons Company.

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Two-dimensional BN-doped ZnO thin-film deposition by a thermionic vacuum arc system

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-020-03258-1 ◽

2020 ◽

Vol 31 (9) ◽

pp. 6948-6955

Author(s):

Mustafa Özgür ◽

Suat Pat ◽

Reza Mohammadigharehbagh ◽

Uğur Demirkol ◽

Nihan Akkurt ◽

...

Keyword(s):

Thin Film ◽

Thin Film Deposition ◽

Film Deposition ◽

Vacuum Arc ◽

Zno Thin Film ◽

Two Dimensional ◽

Doped Zno ◽

Thermionic Vacuum Arc

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Solar Chimney Applications in Buildings

Encyclopedia ◽

10.3390/encyclopedia1020034 ◽

2021 ◽

Vol 1 (2) ◽

pp. 409-422

Author(s):

Haihua Zhang ◽

Yao Tao ◽

Long Shi

Keyword(s):

Natural Ventilation ◽

Energy System ◽

Assisted Ventilation ◽

Building Envelope ◽

Building Structures ◽

Solar Chimney ◽

Climate Conditions ◽

And Performance ◽

Modern Building ◽

Ventilation Systems

A solar chimney is a renewable energy system used to enhance the natural ventilation in a building based on solar and wind energy. It is one of the most representative solar-assisted passive ventilation systems attached to the building envelope. It performs exceptionally in enhancing natural ventilation and improving thermal comfort under certain climate conditions. The ventilation enhancement of solar chimneys has been widely studied numerically and experimentally. The assessment of solar chimney systems based on buoyancy ventilation relies heavily on the natural environment, experimental environment, and performance prediction methods, bringing great difficulties to quantitative analysis and parameterization research. With the increase in volume and complexity of modern building structures, current studies of solar chimneys have not yet obtained a unified design strategy and corresponding guidance. Meanwhile, combining a solar chimney with other passive ventilation systems has attracted much attention. The solar chimney-based integrated passive-assisted ventilation systems prolong the service life of an independent system and strengthen the ventilation ability for indoor cooling and heating. However, the progress is still slow regarding expanded applications and related research of solar chimneys in large volume and multi-layer buildings, and contradictory conclusions appear due to the inherent complexity of the system.

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Proposing Alternative Solutions to Enhance Natural Ventilation Rates in Residential Buildings in the Cfa Climate Zone of Rasht

Sustainability ◽

10.3390/su13020679 ◽

2021 ◽

Vol 13 (2) ◽

pp. 679

Author(s):

Roya Aeinehvand ◽

Amiraslan Darvish ◽

Abdollah Baghaei Daemei ◽

Shima Barati ◽

Asma Jamali ◽

...

Keyword(s):

Natural Ventilation ◽

Residential Buildings ◽

Residential Building ◽

Ventilation Rate ◽

Humid Climate ◽

The Sustainable Development ◽

Passive Strategies ◽

Development Goals ◽

Ventilation Rates ◽

Ventilation Systems

Today, renewable resources and the crucial role of passive strategies in energy efficiency in the building sector toward the sustainable development goals are more indispensable than ever. Natural ventilation has traditionally been considered as one of the most fundamental techniques to decrease energy usage by building dwellers and designers. The main purpose of the present study is to enhance the natural ventilation rates in an existing six-story residential building situated in the humid climate of Rasht during the summertime. On this basis, two types of ventilation systems, the Double-Skin Facade Twin Face System (DSF-TFS) and Single-Sided Wind Tower (SSWT), were simulated through DesignBuilder version 4.5. Then, two types of additional ventilation systems were proposed in order to accelerate the airflow, including four-sided as well as multi-opening wind towers. The wind foldable directions were at about 45 degrees (northwest to southeast). The simulation results show that SSWT could have a better performance than the aforementioned systems by about 38%. Therefore, the multi-opening system was able to enhance the ventilation rate by approximately 10% during the summertime.

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Post-Processing and Surface Characterization of Additively Manufactured Stainless Steel 316L Lattice: Implications for BioMedical Use

Materials ◽

10.3390/ma14061376 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1376

Author(s):

Alex Quok An Teo ◽

Lina Yan ◽

Akshay Chaudhari ◽

Gavin Kane O’Neill

Keyword(s):

Surface Roughness ◽

Stainless Steel ◽

Surface Characterization ◽

High Surface ◽

Surface Characteristics ◽

Post Processing ◽

Stainless Steel 316L ◽

Processing Methods ◽

Particulate Debris

Additive manufacturing of stainless steel is becoming increasingly accessible, allowing for the customisation of structure and surface characteristics; there is little guidance for the post-processing of these metals. We carried out this study to ascertain the effects of various combinations of post-processing methods on the surface of an additively manufactured stainless steel 316L lattice. We also characterized the nature of residual surface particles found after these processes via energy-dispersive X-ray spectroscopy. Finally, we measured the surface roughness of the post-processing lattices via digital microscopy. The native lattices had a predictably high surface roughness from partially molten particles. Sandblasting effectively removed this but damaged the surface, introducing a peel-off layer, as well as leaving surface residue from the glass beads used. The addition of either abrasive polishing or electropolishing removed the peel-off layer but introduced other surface deficiencies making it more susceptible to corrosion. Finally, when electropolishing was performed after the above processes, there was a significant reduction in residual surface particles. The constitution of the particulate debris as well as the lattice surface roughness following each post-processing method varied, with potential implications for clinical use. The work provides a good base for future development of post-processing methods for additively manufactured stainless steel.

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