scholarly journals Investigation of the dispersed composition of dust of inert materials exposed to overload in the manufacture of building materials

2021 ◽  
Vol 937 (2) ◽  
pp. 022083
Author(s):  
B Meskhi ◽  
A Evtushenko ◽  
Yu Startseva ◽  
A Cherhushenko ◽  
A Sakharova
Keyword(s):  
Sedimentation Rate ◽  
Building Materials ◽  
Dust Content ◽  
Crushed Stone ◽  
Dust Particles ◽  
Intense Emission

Abstract At enterprises for the manufacture of building materials, when pouring bulk components, there is an intense emission of dust into the air of the working area of the room. The article presents the results of the dispersed analysis of dust when pouring cement, crushed stone, silicate bricks and chalk, and the integral functions of the distribution of dust particles by diameter are constructed. According to the criteria of Lyashchenko and Reynolds, the results of the sedimentation rate of dust particles were theoretically obtained. Measures are given to reduce the dust content of the air in the working area of the shop.

scholarly journals Environmental and radiation assessment of construction materials in Tyumen

2021 ◽  
Vol 10 (2) ◽  
pp. 40-44
Author(s):  
Elena Viktorovna Zakharova ◽  
Elena Viktorovna Gaevaya ◽  
Leonid Nikolaevich Skipin ◽  
Svetlana Sergeevna Tarasova ◽  
Vasilyа Zinnurovna Burlaenko
Keyword(s):  
Building Materials ◽  
Specific Activity ◽  
Raw Materials ◽  
Natural Radionuclides ◽  
Construction Materials ◽  
Natural Radionuclide ◽  
Maximum Activity ◽  
Crushed Stone ◽  
Natural Activity ◽  
Effective Activity

The current pace of construction leads to the use of large volumes of construction raw materials, which must meet the regulatory indicators, including radiation. High levels of natural radionuclide activity, both in construction and finishing materials, affect changes in the gamma radiation indicators in the premises, which can negatively affect the health of people living in such facilities. Ecological and radiation assessment of building materials for the content of natural radionuclides showed an increased natural activity of potassium-40. The maximum activity values were observed in samples of bricks and expanded clay, where they were 799,0 and 622,0 Bq/kg, respectively. The lowest specific activity of natural potassium was observed in the crushed stone sample (21,3 Bq/kg). The specific activity of thorium-232 in building materials ranged from 2,1 to 53,3 Bq/kg. The activity of radium-226 in all the studied samples ranged from 4,4 Bq/kg (crushed stone) to 55,6 Bq/kg (cement). The specific effective activity of natural radionuclides in the studied building materials does not exceed the standard values (370 Bq/kg), therefore, they can be used in all types of construction and reconstruction.

scholarly journals Research of filter materials for dust fractioning

2021 ◽  
Vol 284 ◽  
pp. 05011
Author(s):  
Vladimir Dmitrienko ◽  
Stanislav Мaslennikov ◽  
Аleksandr Bogomzov
Keyword(s):  
Building Materials ◽  
Measurement Accuracy ◽  
Gravimetric Method ◽  
Microscopic Analysis ◽  
Dust Particles ◽  
Dust Formation ◽  
Dust Emissions ◽  
Specific Location ◽  
Filter Materials ◽  
Blower Performance

A special place in air pollution with dust emissions is occupied by the production of building materials, using large quantities of dispersed mineral substances as aggregates. The article is devoted to the study of hazardous dust fractions emission when assessing the dustiness of the working area for the production of concrete and reinforced concrete products, since the specific location and operation of the equipment complex is characterized by uneven dust formation in space and time. This reduces the efficiency of the aspiration systems. Based on the analysis of methods and means for assessing dustiness, the use of the gravimetric method is justified, however, to assess the content of the most dangerous dust particles for the human body with a size of 2.5 to 10 microns, a size separation of particles is required. Non-woven synthetic filter materials of various thick-nesses and densities are investigated. It is proposed to carry out sampling in blocks with three filters from different filter materials. The studies were carried out with the help of a specially made portable complex. The most effective filter materials were determined with the help of microscopic analysis. The conducted calibration of the blower performance with an assessment of the measurement accuracy showed relatively small errors in the air sampling, which confirms the feasibility of assessing the dustiness of the filter blocks.

The dust content, dust generation, ammonia production, and absorption properties of three different rodent bedding types

1996 ◽  
Vol 30 (1) ◽  
pp. 79-87 ◽  
Author(s):  
F. J. Potgieter ◽  
P. I. Wilke
Keyword(s):  
Moisture Absorption ◽  
Ammonia Concentration ◽  
Dust Content ◽  
Dust Particles ◽  
Ammonia Production ◽  
Dust Production ◽  
Absorption Properties ◽  
Eucalyptus Pulp ◽  
Dust Generation ◽  
Animal Activity

Vermiculite, pine shavings and unbleached eucalyptus pulp contact bedding were compared for dust content, dust production (as a result of animal activity), moisture absorption properties and ammonia production. The percentage of dust particles <300 µm found in pine shavings and vermiculite was 18 and 8 times greater respectively than was found in eucalyptus pulp. The lowest ammonia levels (<1-1 ppm), measured on day 7, were obtained using eucalyptus pulp. Although the ammonia levels obtained for vermiculite compared very well with those of pulp, high levels of dust, up to 5 times more than pulp, were experienced with vermiculite. Pine shavings were associated with the highest ammonia concentration (1-3 ppm), but produced approximately 50% less dust than vermiculite. The water absorption properties obtained for pulp were between 35% and 76% higher than those obtained for vermiculite and pine shavings respectively.

Ion transport in glow discharges with dust

2000 ◽  
Vol 64 (3) ◽  
pp. 263-273 ◽  
Author(s):  
A. P. SUN ◽  
M. GENG ◽  
X. M. QIU
Keyword(s):  
Ion Transport ◽  
Dust Content ◽  
Dust Particles ◽  
Dust Charge ◽  
Neutral Gas ◽  
Glow Discharges ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
And Control

A Monte Carlo method is used to simulate ion transport in a radiofrequency parallel-plate glow discharge with a negative-voltage pulse connected to the electrode. The dust generated during the discharge and a self-consistent electric field are taken into account. Charge exchange and elastic collisions between ions and neutral atoms and the collection and Coulomb scattering of ions on the dust particles are examined during the motion of ions in the sheath. It is found that self-consistent field, neutral gas pressure, and dust charge, dust concentration and dust size influence, to varying degrees, the energy distribution and density of ions arriving at the target, and in particular, the dust charge and concentration have significant influences. As they increase, the number of ions arriving at the target is greatly reduced. In summary, although the dust content is very low (of order 10−3) in most plasma processing devices, its influence cannot be neglected, because of the large dust size and charge (in particular, the former). Therefore, in order to produce good results with ion implantation, coating, stripping, and etching, it is necessary to reduce the dust content and control the size of dust particles.

Use of Clayish Crushed Stone for Production of Aerated Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 269-274
Author(s):  
You Zhi Chen ◽  
Fang Xian Li ◽  
Bing Bo Xu
Keyword(s):  
Building Materials ◽  
Material Design ◽  
Thermal Reaction ◽  
Crushed Stone ◽  
X Ray Diffraction ◽  
Thermal Synthesis ◽  
X Ray ◽  
Technical Parameters ◽  
New Type ◽  
Aerated Concrete

Aerated concrete is a new type of building materials. Clayish crushed stones are regarded as solid waste disposals in China. This paper reports the research outcomes of an experimental study on using clayish crushed stone for the production of aerated concretes of B05 and B06 grade. Hydro-thermal synthesis reaction, mixing proportions, gas-forming and their influences on the concrete performance are investigated. Proper mixing proportions and some important technical parameters are proposed for material design. The microstructure of aerated concrete made with clayish crush stone is analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the hydration products of clayish aerated concrete are composed of poor crystallized C-S-H (B), blade- and needle-shaped Tobermorite and a small amount of granular Hydrogarnet. A homogeneous and densified microstructure was obtained in the aerated concretes with negligible amount of clay after the hydro-thermal reaction in the mixture.

scholarly journals Characterizing the dust content of disk substructures in TW Hydrae

2021 ◽  
Vol 648 ◽  
pp. A33
Author(s):  
E. Macías ◽  
O. Guerra-Alvarado ◽  
C. Carrasco-González ◽  
Á. Ribas ◽  
C. C. Espaillat ◽  
...  
Keyword(s):  
Particle Size ◽  
Mass Measurement ◽  
Radial Profile ◽  
Dust Content ◽  
Dust Particles ◽  
High Angular Resolution ◽  
Streaming Instability ◽  
Maximum Particle Size ◽  
Dust Mass ◽  
Maximum Particle

Context. A key piece of information to understand the origin and role of protoplanetary disk substructures is their dust content. In particular, disk substructures associated with gas pressure bumps can work as dust traps, accumulating grains and reaching the necessary conditions to trigger the streaming instability. Aims. In order to shed some light on the origin and role that disk substructures play in planet formation, we aim to characterize the dust content of substructures in the disk of TW Hya. Methods. We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 3.1 mm with ~50 milliarcsecond resolution. These new data were combined with archival high angular resolution ALMA observations at 0.87, 1.3, and 2.1 mm. We analyze these multiwavelength data to infer a disk radial profile of the dust surface density, maximum particle size, and slope of the particle size distribution. Results. Most previously known annular substructures in the disk of TW Hya are resolved at the four wavelengths. Inside the inner 3 au cavity, the 2.1 and 3.1 mm images show a compact source of free–free emission, likely associated with an ionized jet. Our multiwavelength analysis of the dust emission shows that the maximum particle size in the disk of TW Hya is >1 mm. The inner 20 au are completely optically thick at all four bands, which results in the data tracing different disk heights at different wavelengths. Coupled with the effects of dust settling, this prevents the derivation of accurate density and grain size estimates in these regions. At r > 20 au, we find evidence of the accumulation of large dust particles at the position of the bright rings, indicating that these are working as dust traps. The total dust mass in the disk is between 250 and 330 M⊕, which represents a gas-to-dust mass ratio between 50 and 70. Our mass measurement is a factor of 4.5–5.9 higher than the mass that one would estimate using the typical assumptions of large demographic surveys. Conclusions. Our results indicate that the ring substructures in TW Hya are ideal locations to trigger the streaming instability and form new generations of planetesimals.

scholarly journals THE HYGIENIC ASSESSMENT OF THE WORKING ENVIRONMENT IN INDIVIDUAL OCCUPATIONS IN BUILDING ORGANIZATIONS

2018 ◽  
Vol 97 (12) ◽  
pp. 1203-1209 ◽  
Author(s):  
Olga I. Kopytenkova ◽  
Z. Sh. Tursunov ◽  
A. V. Levanchuk ◽  
O. V. Mironenko ◽  
N. M. Frolova ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Health Risk ◽  
Work Experience ◽  
Building Materials ◽  
New Technologies ◽  
Mineral Wool ◽  
Working Environment ◽  
Dust Particles ◽  
Health Work

Introduction. The development of the construction industry is accompanied by the use of new technologies and building materials. Materials based on mineral wool (MW) became to be widely used. The article presents the results of the study of working environment factors and the determination of the safe for health work experience based on the health risk calculation for workers in contact with MW. Material and methods. To quantify the air pollution of the working area at the construction site, samples were taken using an aspirator and a dust meter. An absorption method using a spectrophotometer was used to determine the chemical composition of the dust. Statistical analysis and mathematical modeling were carried out using a standard software package Microsoft Excel, STADIA. Results. A table for the rapid health risk assessment of workers in contact with MW was developed. The risk of health loss is determined as “High” (R = 11.3). Discussion. Working conditions under the performance of heat-insulating works at facades cladding with the use of MW are classified as harmful (class 3.2) on the dust content in working zone air. In the course of the study, coarse dust and fine dust were found in the air. The data on the change of the dust concentration depending on air humidity, the concentration of dust particles of different dispersion at different distances from the place of work is presented. The chemical composition of dust is presented, the presence of heavy metals is established. Dependences for the determination of safe for health work experience under the influence of the various concentration of dust and the duration of contact are constructed. Сonclusions. On the basis of the research to improve the legal support in the field of occupational health and safety, a number of activities for workers engaged in work with the use of MW are proposed.

Modern Building Materials Using Waste from the Dismantling of Buildings and Structures

2019 ◽  
Vol 945 ◽  
pp. 1016-1023
Author(s):  
L.L. Maslennikova ◽  
N.A. Babak ◽  
I.A. Naginskii
Keyword(s):  
Building Materials ◽  
Mechanical Characteristics ◽  
State Standards ◽  
Crushed Stone ◽  
Thermal Methods ◽  
Ecological Evaluation ◽  
X Ray ◽  
Cement Binder ◽  
Use Efficiency ◽  
Modern Building

In this article the possibility of using construction waste (including waste of dismantling of buildings) when receiving building ceramics, heat-resistant materials based on liquid glass and materials based on natural hardening cement binder is considered. The purpose of study was development of building materials compositions made with using of secondary crushed stone screening HYPERLINK "https://www.multitran.ru/c/m.exe?t=2400068_1_2&s1=%EE%F2%F1%E5%E2" of dismantling of buildings for various purposes, which would suit all state standards. Also these materials would have some improved physical-mechanical characteristics and would be more eco-friendly. Optimum compositions of materials made with use of building mineral waste and physical-mechanical characteristics of received materials are given. For research of waste structure and synthesizable materials structure X-ray phase, differential-thermal methods of analysis and grain size measurements were used. The geological-ecological evaluation of secondary crushed stone screening use efficiency in developed technologies is given.

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