scholarly journals Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

2021 ◽  
Vol 13 (24) ◽  
pp. 14071
Author(s):  
Diana Pinto ◽  
Alcindo Neckel ◽  
Guilherme L. Dotto ◽  
Bashir Adelodun
Keyword(s):  
Fine Particles ◽  
Morphological Changes ◽  
Construction Materials ◽  
Waste Recycling ◽  
Particulate Material ◽  
Future Research ◽  
Material Recycling ◽  
Four Seasons ◽  
Electron Microscopes ◽  
Ultra Fine Particles

Building activity is a significant source of atmospheric contamination by ultrafine dust. Cognizant of this fact, those active in the use and recycling of construction materials must be aware of the risks associated with exposure to nanoparticles (NPs) and ultra-fine particles (UFPs), as well as the associated health impacts. This work analyzed NPs and UFPs generated in a small building-material recycling company using high-resolution electron microscopes and X-ray Diffraction. A self-made passive sampler (LSPS) that can obtain particulate samples without physical and morphological changes, especially where there is a suspension of particulate material, was used in this study. A total of 96 particulate samples, using the LSPS for three months in four seasons, were collected during the study. Thus, the dry deposition of the particles, which are considered highly harmful to human health, was found in each of the four seasons of the year. It is suggested that for future research, the toxicological evaluations of the particulates in the construction industry should be investigated through the consideration of measures to control and mitigate the health risks of workers regarding exposure to NPs and UFPs.

scholarly journals A review on use of recycled municipal and construction solid wastes for manufacturing sustainable construction materials

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Taneya Tom ◽  
Elba Helen George
Keyword(s):  
Solid Waste ◽  
Polymer Composites ◽  
Construction Materials ◽  
Waste Recycling ◽  
Waste To Energy ◽  
Sustainable Construction ◽  
Future Research ◽  
Treatment Technique ◽  
Filling Material ◽  
The Sustainable Development

Huge amount of wastes are being generated, and even though the incineration process reduce the mass of wastes to a large extent, large amount of residues are still remain. The sustainable development of the system should decrease the waste-to-energy ratio continuously through the planned reuse of materials. This paper reviews the existing studies on recycling municipal and construction solid waste for the manufacture of Geo polymer composites. The principal findings of this work reveal that municipal and construction solid waste could be successfully used into Geo polymer composites as an alternative in the forms of precursor, aggregate, additive, reinforcement fibres, or filling material. Additionally, the results indicate that although the inclusion of such waste might depress some attributes of Geo polymer composites, proper proportion design and suitable treatment technique could solve these detrimental effects. Finally, a brief discussion is provided to identify the important needs in the future research and development for promoting the utilization of solid waste materials in the forthcoming sustainable geo polymer industry. In summary, this work offers guidance for a greener approach to building – scoring favourably in environmental performance for being relevant to resource conservation, landfill diversion, and waste recycling. Keywords: Construction materials, Geo polymer composite, Municipal solid waste, Construction solid waste, Sustainability.

Studies of copper selenide ultrafine particles by newly developed gas evaporation method

1990 ◽  
Vol 48 (4) ◽  
pp. 306-307
Author(s):  
Chihiro Kaito ◽  
Yoshio Saito
Keyword(s):  
Crystal Structure ◽  
Ultrafine Particles ◽  
Fine Particles ◽  
Production Method ◽  
Atmospheric Temperature ◽  
Copper Selenide ◽  
Quartz Boat ◽  
Selenium Vapor ◽  
Ar Gas ◽  
Ultra Fine Particles

The direct evaporation of metallic oxides or sulfides does not always given the same compounds with starting material, i.e. decomposition took place. Since the controll of the sulfur or selenium vapors was difficult, a similar production method for oxide particles could not be used for preparation of such compounds in spite of increasing interest in the fields of material science, astrophysics and mineralogy. In the present paper, copper metal was evaporated from a molybdenum silicide heater which was proposed by us to produce the ultra-fine particles in reactive gas as shown schematically in Figure 1. Typical smoke by this method in Ar gas at a pressure of 13 kPa is shown in Figure 2. Since the temperature at a location of a few mm below the heater, maintained at 1400° C , were a few hundred degrees centigrade, the selenium powder in a quartz boat was evaporated at atmospheric temperature just below the heater. The copper vapor that evaporated from the heater was mixed with the stream of selenium vapor,and selenide was formed near the boat. If then condensed by rapid cooling due to the collision with inert gas, thus forming smoke similar to that from the metallic sulfide formation. Particles were collected and studied by a Hitachi H-800 electron microscope.Figure 3 shows typical EM images of the produced copper selenide particles. The morphology was different by the crystal structure, i.e. round shaped plate (CuSe;hexagona1 a=0.39,C=l.723 nm) ,definite shaped p1 ate(Cu5Se4;Orthorhombic;a=0.8227 , b=1.1982 , c=0.641 nm) and a tetrahedron(Cu1.8Se; cubic a=0.5739 nm). In the case of compound ultrafine particles there have been no observation for the particles of the tetrahedron shape. Since the crystal structure of Cu1.8Se is the anti-f1uorite structure, there has no polarity.

Twin boundary structure of a Y-Ba-Cu-O superconductor

1989 ◽  
Vol 47 ◽  
pp. 168-169
Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu
Keyword(s):  
Twin Boundary ◽  
Fine Particles ◽  
Imaging Techniques ◽  
Fine Powder ◽  
Orthorhombic Phase ◽  
Boundary Structure ◽  
Crystallographic Axis ◽  
System A ◽  
High Resolution Structure ◽  
Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

scholarly journals Review on the Use of Artificial Intelligence to Predict Fire Performance of Construction Materials and Their Flame Retardancy

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1022
Author(s):  
Hoang T. Nguyen ◽  
Kate T. Q. Nguyen ◽  
Tu C. Le ◽  
Guomin Zhang
Keyword(s):  
Artificial Intelligence ◽  
Flame Retardancy ◽  
Material Science ◽  
Construction Materials ◽  
Engineering Problem ◽  
Future Research ◽  
Fire Performance ◽  
Structural Components ◽  
Comprehensive Overview ◽  
Fire Engineering

The evaluation and interpretation of the behavior of construction materials under fire conditions have been complicated. Over the last few years, artificial intelligence (AI) has emerged as a reliable method to tackle this engineering problem. This review summarizes existing studies that applied AI to predict the fire performance of different construction materials (e.g., concrete, steel, timber, and composites). The prediction of the flame retardancy of some structural components such as beams, columns, slabs, and connections by utilizing AI-based models is also discussed. The end of this review offers insights on the advantages, existing challenges, and recommendations for the development of AI techniques used to evaluate the fire performance of construction materials and their flame retardancy. This review offers a comprehensive overview to researchers in the fields of fire engineering and material science, and it encourages them to explore and consider the use of AI in future research projects.

scholarly journals New Maskless Film Making Method Using Ultra Fine Particles.

Materia Japan ◽  
1995 ◽  
Vol 34 (4) ◽  
pp. 455-460 ◽  
Author(s):  
Eiji Fuchita ◽  
Masaaki Oda ◽  
Chikara Hayashi
Keyword(s):  
Fine Particles ◽  
Ultra Fine Particles ◽  
Film Making

Environmental assessment of construction and demolition waste recycling in Bolivia: Focus on transportation distances and selective collection rates

2021 ◽  
pp. 0734242X2110291
Author(s):  
Navarro Ferronato ◽  
Gabriela Edith Guisbert Lizarazu ◽  
Marcelo Antonio Gorritty Portillo ◽  
Luca Moresco ◽  
Fabio Conti ◽  
...  
Keyword(s):  
Developing Countries ◽  
Environmental Impacts ◽  
Waste Recycling ◽  
Construction And Demolition Waste ◽  
Primary Data ◽  
Demolition Waste ◽  
Collection Rate ◽  
Material Recycling ◽  
Material Recovery ◽  
Selective Collection

Construction and demolition waste (CDW) management in developing countries is a global concern. The analysis of scenarios and the implementation of life cycle assessment (LCA) support decision-makers in introducing integrated CDW management systems. This paper introduces the application of an LCA in La Paz (Bolivia), where CDW is mainly dumped in open areas. The aim of the research is to evaluate the benefits of inert CDW recycling in function of the selective collection rate, defined as the amount of waste (%wt.) sorted at the source in relation to the total waste amount produced, and the distances from the CDW generation to the material recycling facility. The outcomes of the research suggest that increasing the selective collection rates (5% to 99%) spread the importance of transportation distances planning since it affects the magnitude of the environmental impacts (1.05 tCO2-eq to 20.7 tCO2-eq per km traveled). Transportation limits have been found to be lower than about 40 km in order to make recycling beneficial for all environmental impacts and for all selective collection rate, with the eutrophication potential as the limiting indicator. The theoretical analysis suggests implementing LCA with primary data and involving statistics related to the transportation of virgin materials avoided thanks to recycling. The outcomes of the research support the implementation of CDW recycling in developing countries since it has been found that material recovery is always beneficial.

Ultrafeine Partikel im Abgas von Humankremationsanlagen/Ultra-fine particles in the flue gas of human crematories

Gefahrstoffe ◽  
2020 ◽  
Vol 80 (01-02) ◽  
pp. 19-24 ◽  
Author(s):  
M. Köhler ◽  
A. Ohle ◽  
M. Beckmann ◽  
S. Steinau ◽  
F. Tettich ◽  
...  
Keyword(s):  
Flue Gas ◽  
Fine Particles ◽  
Ultra Fine Particles

Der Anteil an Kremationen (Feuerbestattungen) nimmt in Deutschland seit Jahren zu und umfasst bereits mehr als 65 % aller Bestattungen. Grenzwerte für die Emissionen von Feinstaub oder die Anzahl ultrafeiner Partikel (UFP) existieren nicht und bisher sind auch keine systematischen Untersuchungen bekannt, welche Partikelemissionen in Krematorien auftreten. Daher kann zum aktuellen Zeitpunkt nicht beurteilt werden, ob es sich bei Krematorien um nennenswerte Feinstaubquellen handelt. Um diese Lücke zu schließen, wurden die reingasseitigen UFP-Konzentrationen in zehn Krematorien unterschiedlichen Bau- bzw. Modernisierungsjahres und mit verschiedenen Abgasreinigungstechnologien gemessen. Über die Kremationsdauer gemittelte UFP-Konzentrationen zwischen 1,19 · 10³ und 4,26 · 107 cm–3 wurden erfasst. Die höchsten Konzentrationen zeigten sich bei Anlagen mit Flugstromverfahren, deren Filtereinheiten unmittelbar vor der nächsten Revision standen. Bei Anlagen gleichen Typs mit gewarteten Filtereinheiten lag die mittlere UFP-Konzentration zwei Größenordnungen darunter.

Vaporization and Ultra-Fine Particle Generation during the Plasma Spraying Process

1997 ◽  
Author(s):  
K.A. Gross ◽  
P. Fauchais ◽  
M. Vardelle ◽  
J. Tikkanen ◽  
J. Keskinen
Keyword(s):  
Fine Particles ◽  
High Concentration ◽  
Thermal Spray Process ◽  
Particle Generation ◽  
Spray Process ◽  
Ultra Fine Particle ◽  
Fast Cooling ◽  
Ultra Fine Particles ◽  
Plasma Spraying Process ◽  
Very High

Abstract The thermal spray process melts powder at very high temperatures and propels the molten material to the substrate to produce a coherent deposit. This heating produces a certain amount of vaporization of the feedstock. Upon exiting the plasma plume the fast cooling conditions lead to condensation of the vapor. An electrical low pressure impactor was used to monitor the concentration of ultra-fine particles at various radial and axial distances. Metal, namely iron powder, showed very high concentration levels which increase with distance. Ultra-fine particles from ZrO2-8Y2O3 reached a peak concentration at 6 cm. Use of an air barrier during spraying decreases the population of ultra-fine particles facilitating the production of a stronger coating.

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