The Granularity of Dust Particles when Sanding Wood and Wood-Based Materials

2014 ◽  
Vol 1001 ◽  
pp. 432-437 ◽  
Author(s):  
Alena Očkajová ◽  
Ján Stebila ◽  
Marek Rybakowski ◽  
Tomasz Rogozinski ◽  
L'uboš Krišták ◽  
...  
Keyword(s):  
Particle Size ◽  
Granulometric Composition ◽  
Working Environment ◽  
Dust Particles ◽  
Safety Measures ◽  
Different Types ◽  
Sieve Analyses ◽  
Narrow Belt ◽  
Technical Safety

The article presents results of the granulometric composition of chip particles when sanding wood (beech) and wood-based materials (particleboard and semi-hardboard) using different types of sanders – wide belt sander, narrow belt sander, and hand sander. On the basis of the carried out sieve analyses, the proportion of produced particles, which can be marked as dust with the particle size of ≤ 80 μm, is high at the interval from 89.21% - 96.29 %. The highest percentage of dust particles was reached at dust from the hand disk sander. At the end of the article we point to possible technical safety measures – additional dust exhausting, suction, to possibly reduce the dust getting to the working environment.

Engineering Solutions of Ensuring Safety when Performing High-Rise Works from the Ladders

2020 ◽  
pp. 65-70
Author(s):  
V.A. Senchenko ◽  
◽  
T.T. Kaverzneva ◽  
I.L. Skripnik ◽  
S.V. Voronin ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Human Factor ◽  
Safety Measures ◽  
Freedom Of Movement ◽  
High Rise ◽  
Different Types ◽  
The Coefficient Of Friction ◽  
The Stability ◽  
Safety Systems ◽  
Technical Safety

A great number of injuries when performing the work at height are recorded when falling from the stairs. Injuries due to falling from height including ladders are usually severe and even fatal. At the same time, about 70 % of injuries occur with portable ladders. Most often, the fall of a person is caused by the effect of sliding ladders and breaking the stability of its overall structure. One of the ways to increase the stability of the ladder is to use attachments on its upper part. Depending on the method of coupling with the support, the possibility of adjusting the coupling area, as well as the presence of built-in safety systems, different types of attachments are used. The article considers the forces that cause the slip and fall of the ladder when using it in work. Engineering solutions aimed at preventing the upper part of the ladder from slipping while working on the support are presented. The systematization is carried out concerning the available attachments on ladder by the method of coupling with the support. The evaluation of these engineering solutions in various ways of their application is carried out. A mathematical model is proposed for risk assessment when performing work at height using ladders with attachments. The stability of the ladder with the attachment will be higher, the greater the coefficient of friction of the attachment and the less degrees of freedom of movement in the «attachment — support» bundle. An empirical conclusion is made that the safest attachment at the top of the ladder will be the structure that is fixed on the support. The attachment with an anchor point ensures the safety of work at height, but it is not suitable in all cases. There is no universal effective engineering solution to ensure the safety of work at height from the ladder. Technical safety measures have great potential, since they allow eliminating the human factor in this process.

Organizational and technical safety measures during testing of medium and light military ground-based robotic complexes

2019 ◽  
Vol 7 (3) ◽  
pp. 176-182
Author(s):  
Eugeniy Antokhin ◽  
Oleg Petrashko ◽  
Plamena Chernova ◽  
Valentin Panichev
Keyword(s):  
Safety Measures ◽  
Technical Safety

scholarly journals Evaluation of Marblewood Dust’s (Marmaroxylon racemosum) Effect on Ignition Risk

2021 ◽  
Vol 11 (15) ◽  
pp. 6874
Author(s):  
Miroslava Vandličkova ◽  
Iveta Markova ◽  
Katarina Holla ◽  
Stanislava Gašpercová
Keyword(s):  
Particle Size ◽  
Dust Particles ◽  
Wood Dust ◽  
Sieve Analysis ◽  
Granulometric Analysis ◽  
Analysis Measurement ◽  
Risk Research ◽  
Minimum Ignition Temperature ◽  
The Impact

The paper deals with the selected characteristics, such as moisture, average bulk density, and fraction size, of tropical marblewood dust (Marmaroxylon racemosum) that influence its ignition risk. Research was focused on sieve analysis, granulometric analysis, measurement of moisture level in the dust, and determination of the minimum ignition temperatures of airborne tropical dust and dust layers. Samples were prepared using a Makita 9556CR 1400W grinder and K36 sandpaper for the purpose of selecting the percentages of the various fractions (<63, 63, 71, 100, 200, 315, 500 μm). The samples were sized on an automatic vibratory sieve machine Retsch AS 200. More than 65% of the particles were determined to be under 100 μm. The focus was on microfractions of tropical wood dust (particles with a diameter of ≤100 µm) and on the impact assessment of particle size (particle size <100 µm) on the minimum ignition temperatures of airborne tropical dust and dust layers. The minimum ignition temperature of airborne marblewood dust decreased with the particle size to the level of 400 °C (particle size 63 μm).

Investigation of the different particle size dust releases from rigid filter candles during pulse-jet cleaning

2021 ◽  
pp. 095440622110179
Author(s):  
Xin Luan ◽  
Zhongli Ji ◽  
Longfei Liu ◽  
Ruifeng Wang
Keyword(s):  
Particle Size ◽  
Critical Role ◽  
Operating Conditions ◽  
Solid Particles ◽  
Dust Particles ◽  
Cleaning Efficiency ◽  
Term Operation ◽  
Cleaning Performance ◽  
Experimental Apparatus ◽  
Pulse Jet

Rigid filters made of ceramic or metal are widely used to remove solid particles from hot gases at temperature above 260 °C in the petrochemical and coal industries. Pulse-jet cleaning of fine dust from rigid filter candles plays a critical role in the long-term operation of these filters. In this study, an experimental apparatus was fabricated to investigate the behavior of a 2050 mm filter candle, which included monitoring the variation of pressure dynamic characteristics over time and observing the release of dust layers that allowed an analysis of the cleaning performance of ISO 12103-1 test dusts with different particle size distributions. These results showed the release behavior of these dusts could be divided into five stages: radial expansion, axial crack, flaky release, irregular disruption and secondary deposition. The cleaning performance of smaller sized dust particles was less efficient as compared with larger sized dust particles under the same operating conditions primarily because large, flaky-shaped dust aggregates formed during the first three stages were easily broken into smaller, dispersed fragments during irregular disruption that forced more particles back to the filter surface during secondary deposition. Also, a “low-pressure and long-pulse width” cleaning method improved the cleaning efficiency of the A1 ultrafine test dust from 81.4% to 95.9%.

The Analysis on Manufacture Cost of Fire Robot Based on Modular Design

2014 ◽  
Vol 716-717 ◽  
pp. 1518-1521
Author(s):  
Shu Fang ◽  
Yan Xu ◽  
Fei Dong
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Working Environment ◽  
Activity Based Costing ◽  
Traditional Design ◽  
Different Types ◽  
Function Modules ◽  
Flexible Manufacture ◽  
Technical Platform ◽  
General Technical

The manufacture of fire robot has characteristics such as different types and piece production, and flexible manufacture and cost control of the fire robot must be considered due to these characteristics. In this paper, the similarity of fire robot’s working environment was analyzed, The demand of chassis’s adaptability and the method using general technical platform were discussed with the thinking of modular design, and new series fire robots which composed of the general platform and different function modules were proposed, and the manufacture cost of traditional design method and modular design method were compared in using the activity-based costing method, and under the new design method the manufacture cost were decreased extremely.

scholarly journals Observations of Saharan dust microphysical and optical properties from the Eastern Atlantic during NAMMA airborne field campaign

2011 ◽  
Vol 11 (2) ◽  
pp. 723-740 ◽  
Author(s):  
G. Chen ◽  
L. D. Ziemba ◽  
D. A. Chu ◽  
K. L. Thornhill ◽  
G. L. Schuster ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Dust Particle ◽  
Saharan Dust ◽  
Dust Particles ◽  
Small Range ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Field Campaign ◽  
Sahara Dust

Abstract. As part of the international project entitled "African Monsoon Multidisciplinary Analysis (AMMA)", NAMMA (NASA AMMA) aimed to gain a better understanding of the relationship between the African Easterly Waves (AEWs), the Sahara Air Layer (SAL), and tropical cyclogenesis. The NAMMA airborne field campaign was based out of the Cape Verde Islands during the peak of the hurricane season, i.e., August and September 2006. Multiple Sahara dust layers were sampled during 62 encounters in the eastern portion of the hurricane main development region, covering both the eastern North Atlantic Ocean and the western Saharan desert (i.e., 5–22° N and 10–35° W). The centers of these layers were located at altitudes between 1.5 and 3.3 km and the layer thickness ranged from 0.5 to 3 km. Detailed dust microphysical and optical properties were characterized using a suite of in-situ instruments aboard the NASA DC-8 that included a particle counter, an Ultra-High Sensitivity Aerosol Spectrometer, an Aerodynamic Particle Sizer, a nephelometer, and a Particle Soot Absorption Photometer. The NAAMA sampling inlet has a size cut (i.e., 50% transmission efficiency size) of approximately 4 μm in diameter for dust particles, which limits the representativeness of the NAMMA observational findings. The NAMMA dust observations showed relatively low particle number densities, ranging from 268 to 461 cm−3, but highly elevated volume density with an average at 45 μm3 cm−3. NAMMA dust particle size distributions can be well represented by tri-modal lognormal regressions. The estimated volume median diameter (VMD) is averaged at 2.1 μm with a small range of variation regardless of the vertical and geographical sampling locations. The Ångström Exponent assessments exhibited strong wavelength dependence for absorption but a weak one for scattering. The single scattering albedo was estimated at 0.97 ± 0.02. The imaginary part of the refractive index for Sahara dust was estimated at 0.0022, with a range from 0.0015 to 0.0044. Closure analysis showed that observed scattering coefficients are highly correlated with those calculated from spherical Mie-Theory and observed dust particle size distributions. These values are generally consistent with literature values reported from studies with similar particle sampling size range.

scholarly journals Digital Wallet System for Smart Ticketing

2016 ◽  
Vol 5 (1) ◽  
pp. 12
Author(s):  
Vinay Kumar Reddy Kaitha ◽  
Bala Naga Vamsidhar Grandhi ◽  
Vinay Babu Kosaraju
Keyword(s):  
Indian Subcontinent ◽  
Transportation System ◽  
Working Environment ◽  
Paper Briefly ◽  
Maintenance Costs ◽  
Different Types ◽  
Digital Wallet

<div><p class="Abstract"><em>This paper briefly discusses an effective, efficient, convenient ticketing system designed especially for the transportation system in the Indian Subcontinent, which can be also extended to different types of domain by introducing few changes in design according to working environment. This system reduces man power which in turn reduces the maintenance costs to a greater extent.</em></p></div>

Proteins Induced Formation of Hydrothermal Nitrogen Doped Carbons

2009 ◽  
Vol 1219 ◽  
Author(s):  
Niki Baccile ◽  
Maria-Magdalena Titirici
Keyword(s):  
Particle Size ◽  
Carbon Source ◽  
Nitrogen Sources ◽  
Model Compounds ◽  
Nitrogen Doped ◽  
Carbon Particles ◽  
Structural Order ◽  
Different Types

AbstractThis contribution illustrates the synthesis of nitrogen-containing hydrothermal carbon particles from a mixture of glucose, as carbon source, and different types of proteins, as nitrogen sources. Casein, ovalbumin, hemoglobin and gelatin were chosen here as model compounds. The particle size and the level of structural order could be tuned according to the protein type and the amount utilized.

scholarly journals Streaming instability of multiple particle species in protoplanetary disks

2018 ◽  
Vol 618 ◽  
pp. A75 ◽  
Author(s):  
Noemi Schaffer ◽  
Chao-Chin Yang ◽  
Anders Johansen
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Protoplanetary Disks ◽  
Single Species ◽  
Stokes Number ◽  
Dust Particles ◽  
Particle Sizes ◽  
Particle Species ◽  
Streaming Instability ◽  
Large Particles

The radial drift and diffusion of dust particles in protoplanetary disks affect both the opacity and temperature of such disks, as well as the location and timing of planetesimal formation. In this paper, we present results of numerical simulations of particle-gas dynamics in protoplanetary disks that include dust grains with various size distributions. We have considered three scenarios in terms of particle size ranges, one where the Stokes number τs = 10−1−100, one where τs = 10−4−10−1, and finally one where τs = 10−3−100. Moreover, we considered both discrete and continuous distributions in particle size. In accordance with previous works we find in our multispecies simulations that different particle sizes interact via the gas and as a result their dynamics changes compared to the single-species case. The larger species trigger the streaming instability and create turbulence that drives the diffusion of the solid materials. We measured the radial equilibrium velocity of the system and find that the radial drift velocity of the large particles is reduced in the multispecies simulations and that the small particle species move on average outwards. We also varied the steepness of the size distribution, such that the exponent of the solid number density distribution, dN∕da ∝ a−q, is either q = 3 or q = 4. Overall, we find that the steepness of the size distribution and the discrete versus continuous approach have little impact on the results. The level of diffusion and drift rates are mainly dictated by the range of particle sizes. We measured the scale height of the particles and observe that small grains are stirred up well above the sedimented midplane layer where the large particles reside. Our measured diffusion and drift parameters can be used in coagulation models for planet formation as well as to understand relative mixing of the components of primitive meteorites (matrix, chondrules and CAIs) prior to inclusion in their parent bodies.

scholarly journals Size-segregated characteristics of organic carbon (OC), elemental carbon (EC) and organic matter in particulate matter (PM) emitted from different types of ships in China

2020 ◽  
Vol 20 (3) ◽  
pp. 1549-1564 ◽  
Author(s):  
Fan Zhang ◽  
Hai Guo ◽  
Yingjun Chen ◽  
Volker Matthias ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Particle Mass ◽  
Fuel Oil ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Heavy Fuel Oil ◽  
Different Types ◽  
Marine Diesel

Abstract. Studies of detailed chemical compositions in particles with different size ranges emitted from ships are in serious shortage. In this study, size-segregated distributions and characteristics of particle mass, organic carbon (OC), elemental carbon (EC), 16 EPA polycyclic aromatic hydrocarbons (PAHs) and 25 n-alkanes measured aboard 12 different vessels in China are presented. The results showed the following. (1) More than half of the total particle mass, OC, EC, PAHs and n-alkanes were concentrated in fine particles with aerodynamic diameter (Dp) < 1.1 µm for most of the tested ships. The relative contributions of OC, EC, PAH and alkanes to the size-segregated particle mass are decreasing with the increase in particle size. However, different types of ships showed quite different particle-size-dependent chemical compositions. (2) In fine particles, the OC and EC were the dominant components, while in coarse particles, OC and EC only accounted for very small proportions. With the increase in particle size, the OC / EC ratios first decreased and then increased, having the lowest values for particle sizes between 0.43 and 1.1 µm. (3) Out of the four OC fragments and three EC fragments obtained in thermal–optical analysis, OC1, OC2 and OC3 were the dominant OC fragments for all the tested ships, while EC1 and EC2 were the main EC fragments for ships running on heavy fuel oil (HFO) and marine-diesel fuel, respectively; different OC and EC fragments presented different distributions in different particle sizes. (4) The four-stroke low-power diesel fishing boat (4-LDF) had much higher PAH emission ratios than the four-stroke high-power marine-diesel vessel (4-HMV) and two-stroke high-power heavy-fuel-oil vessel (2-HHV) in fine particles, and 2-HHV had the lowest values. (5) PAHs and n-alkanes showed different profile patterns for different types of ships and also between different particle-size bins, which meant that the particle size should be considered when source apportionment is conducted. It is also noteworthy from the results in this study that the smaller the particle size, the more toxic the particle was, especially for the fishing boats in China.

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