scholarly journals THE EFFECT OF CAVITATION TREATMENT ON THE EXTINGUISHING OF PARTICLES OF OILS IN FUEL BOILERS

2019 ◽  
Vol 20 (9-10) ◽  
pp. 52-59
Author(s):  
M. A. Taymarov ◽  
R. V. Akhmetova ◽  
S. M. Margulis ◽  
L. I. Kasimova
Keyword(s):  
Particle Size ◽  
Combustion Zone ◽  
Consumption Rate ◽  
Fuel Oil ◽  
Particle Sizes ◽  
Oil Consumption ◽  
Boiler Efficiency ◽  
Large Particles ◽  
Oil Particles

The difficulties of burning the watered fuel oil used at the TPP as a reserve fuel for boilers are associated with its preparation by heating to reduce viscosity and the choice of a method of spraying with nozzles into the combustion zone. The quality of the preparation of fuel oil for combustion affecting the boiler efficiency is estimated by the length of the flame, the presence of burning large particles of fuel oil, the injection of coke and unburned particles onto screen and other heat-receiving surfaces. One of the ways to prepare fuel oil for combustion is cavitation treatment, which results in an emulsion consisting of fine micronsized particles. Heating of fuel oil particles after the nozzle in contact with the combustion zone is due to the flow of radiation from the burning torch. Therefore, in this article, the values of the flux density from the torch during the combustion of fuel oil are experimentally determined. The influence of particle size on the burning rate of the fuel oil M100 with the different density of the thermal radiation of the flame. It is found that the effect of cavitation treatment of fuel oil on the combustion rate is most significantly manifested in particle sizes less than 10 microns. For this purpose, the use of hydrodynamic cavitators are preferred at high fuel oil consumption rate.

scholarly journals KUALITAS PAPAN KOMPOSIT DARI LIMBAH FINIR KAYU LAPIS BERDASARKAN UKURAN PARTIKEL DAN WAKTU PENGEMPAAN DENGAN MENGGUNAKAN PEREKAT LIMBAH PLASTIK POLIPROPILENA

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Alfonsus Rodriquez ◽  
Ahmad Yani ◽  
Fathul Yusro
Keyword(s):  
Particle Size ◽  
Physical And Mechanical Properties ◽  
Particle Sizes ◽  
Hot Press ◽  
Factor B ◽  
Pressing Time ◽  
Materials Used ◽  
Absorption Thickness ◽  
Water Contents

This study aims to analyze the quality of composite boards from plywood veneers waste and polypropylene plastic waste adhesives base on particle sizes, pressing times, and both of interaction towards physical and mechanical properties also to obtain the particle sizes and pressing time properly with the result that produce the qualified standard boards of JIS A 5908-2003. This research carried out at the wood workshop, laboratory of technology and processing of woods (the faculty of forestry, university of Tanjungpura), and the laboratory of PT. Duta Pertiwi Nusantara. The materials used in this study were plywood veneers waste and polypropylene plastic by 50% : 50% comparison. The research method was utilized the completely randomized factorial design by two treatment factors. Factor A was particle sizes that consisting of 6 mesh, 8 mesh, and 10 mesh. Factor B was pressing time that consisting of 10 minutes, 15 minute, and 20 minutes. Composite boards were created by 30 x 30 x 1 size in centimetres by means the density target was 0,7 gr/cm3. The pressing was done by hot press in 180oC temperature and composite boards conditioning for 14 days. The results of this study showed that the density, water absorption, thickness, Modulus of Repture (MOR), internal bonding, holding strength of screws in the composite boards have been qualified the standard of JIS A 5908-2003. While, the water contents and Modulus of Elasticity (MOE) testing were not qualified the standard of JIS 5908-2003. The treatment that produce the optimum composite boards which quality JIS A 5908-2003 standard was on the 8 mesh particle size treatment by means of 15 minutes pressing time.Keywords: Composite Board, Particle Size, Polypropylene Plastics, Pressing Time, Veneers Waste.

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.

Die Gelchromatographie großer Partikel und ihre Grenzen / Limitation of Particles Size in Gel Chromatography

1970 ◽  
Vol 25 (11) ◽  
pp. 1235-1239 ◽  
Author(s):  
Wolfram Gerlich ◽  
Helmut Determann ◽  
Theodor Wieland
Keyword(s):  
Particle Size ◽  
Brownian Motion ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Gel Chromatography ◽  
Particle Sizes ◽  
E Coli ◽  
Large Particles ◽  
Cellulose Gel

The behaviour of molecules and particles of 2 - 400 nm radius in gel chromatography was investigated using sephadex, agarose, and pearl shaped cellulose gel of different porosity. Correlations between elution volumes and particle sizes are given in Fig. 1. We found that particles from ca. 400 nm diameter upwards were more or less irreversibly adsorbed depending on the particle size. So only 15% of rat liver mitochondria and 5% of E. coli bacteria could be eluted from the loose cellulose Cu3. It is assumed that this adsorption is due to the absence of Brownian motion of large particles, which therefore are more or less subject to the gravity and to adsorption forces of the gel.

EFFECTS OF CHANGES IN ATTRIBUTES OF RETICULAR CONTRACTION ON FECAL PARTICLE SIZES IN CATTLE

1990 ◽  
Vol 70 (1) ◽  
pp. 159-166 ◽  
Author(s):  
E. K. OKINE ◽  
G. W. MATHISON ◽  
R. T. HARDIN
Keyword(s):  
Particle Size ◽  
High Weight ◽  
Geometric Mean ◽  
Latin Square ◽  
Design Experiment ◽  
Particle Sizes ◽  
Low Weight ◽  
Large Particles ◽  
Mean Size ◽  
Period Duration

A 3 × 3 Latin square design experiment was conducted with three ruminally-cannulated Hereford steers (605 ± SD 98 kg) to determine the effects of changes in reticular contraction characteristics on the distribution of fecal particle size of cattle fed at maintenance. Addition of 0 (control; C) 9 (low weight; LW) or 18 (high weight; HW) kg weight to ventral sac of the rumen of steers linearly increased (P = 0.03) the geometric mean size of fecal particles. During the 1.5-h feeding period, duration and amplitude of reticular contractions linearly increased (P = 0.04) and decreased (P = 0.08), respectively, with the addition of weights. Frequency of reticular contractions increased linearly (P = 0.05) and quadratically (P = 0.07), reaching a maximum of 1.7 min−1 in LW steers, 1.6 min−1 and 1.4 min−1 in HW and C steers, respectively. Duration of reticular contractions, but not amplitude or frequency, was linearly related to the proportion of large particles and to the geometric mean size of fecal particles (r = 0.90, P = 0.002; and r = 0.61, P = 0.08, respectively). It was concluded that the increase in fecal geometric mean and the change in the distribution of fecal particle sizes with increasing weights in the rumen was associated with increases in the duration of reticular contractions rather than changes in frequency or amplitude. Key words: Steers, reticular contractions, fecal particle size, rumen, weight

scholarly journals Effect of particle sizes and sodium hydroxide concentrations on silica extraction from minerals obtained in Kalirejo village, Kokap, Kulonprogo, Yogyakarta

Eksergi ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 29
Author(s):  
Tutik Muji Setyoningrum ◽  
Wibiana Wulan Nandari ◽  
Sri Wahyu Murni ◽  
Muhamad Maulana Azimatun Nur
Keyword(s):  
Particle Size ◽  
Glass Ceramics ◽  
Extraction Process ◽  
Extraction Yield ◽  
Liquid Extraction ◽  
Refining Process ◽  
Particle Sizes ◽  
Small Communities ◽  
Solid Liquid

Silica is mainly used in the production of rubber, glass, cement, glass, ceramics, paper, cosmetics, electronics, paintings, healthcare and other industries. Kalirejo village has a potential abundant resource of silica minerals. However, to refine it, high cost of extraction should be done to obtain high purity of silica. Different refining methods influence different purity of the silica. The purpose of this research was to study the refining process of mineral rock silica from Kalirejo village, Kokap, Kulonprogo by emplying simple and cheap solid-liquid extraction. Extraction was done by varying the particle size at 100 - 200 mesh, while NaOH concentration was varied in 0.5 N to 5 N.  Results showed that minerals taken from Kalirejo village was dominated by silica (23%).  The largest extract (4.89 gram) was obtained at 200 mesh and using NaOH 5 N with yield of 15.07%. Higher NaOH and higher particle size enhanced the extraction yield. This finding could help small communities in Kalirejo village to enhance the quality of silica by employing simple and cheap extraction process.

scholarly journals VIS-NIR/SWIR Spectral Properties of H2O Ice Depending on Particle Size and Surface Temperature

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1328
Author(s):  
Katrin Stephan ◽  
Mauro Ciarniello ◽  
Olivier Poch ◽  
Bernard Schmitt ◽  
David Haack ◽  
...  
Keyword(s):  
Particle Size ◽  
Spectral Signature ◽  
Particle Sizes ◽  
Icy Satellites ◽  
Spectral Parameters ◽  
Spectral Changes ◽  
Large Particles ◽  
Band Depth ◽  
Increasing Temperature ◽  
Particle Shapes

Laboratory measurements were performed to study the spectral signature of H2O ice between 0.4 and 4.2 µm depending on varying temperatures between 70 and 220 K. Spectral parameters of samples with particle sizes up to ~1360 µm, particle size mixtures, and different particle shapes were analyzed. The band depth (BD) of the major H2O-ice absorptions at 1.04, 1.25, 1.5, and 2 µm offers an excellent indicator for varying particle sizes in pure H2O ice. The spectral changes due to temperature rather, but not exclusively, affect the H2O-ice absorptions located at 1.31, 1.57, and 1.65 µm and the Fresnel reflection peaks at 3.1 and 3.2 µm, which strongly weaken with increasing temperature. As the BDs of the H2O-ice absorptions at 1.31, 1.57, and 1.65 µm increase, the band centers (BCs) of the H2O-ice absorptions at 1.25 and 1.5 µm slightly shift to shorter wavelengths. However, the BCs of the strong H2O-ice absorptions can also be affected by saturation in the case of large particles. The collected spectra provide a useful spectral library for future investigations of icy satellites such as Ganymede and Callisto, the major targets of ESA’s JUICE mission.

scholarly journals Influence of Grit Size and Wood Species on the Granularity of Dust Particles during Sanding

2020 ◽  
Vol 10 (22) ◽  
pp. 8165
Author(s):  
Marta Pędzik ◽  
Kinga Stuper-Szablewska ◽  
Maciej Sydor ◽  
Tomasz Rogoziński
Keyword(s):  
Particle Size ◽  
Grit Size ◽  
Dust Particles ◽  
Wood Dust ◽  
Particle Sizes ◽  
Respirable Fraction ◽  
Dust Fraction ◽  
The Mean ◽  
Oak Ash

Wood dust poses a threat to the health of employees and the risk of explosion and fire, accelerates the wear of machines, worsens the quality of processing, and requires large financial outlays for its removal. The aim of this study was to investigate the extent to which the grit size of sandpaper influences the size of the wood dust particles and the proportion of the finest particles which, when dispersed in the air, may constitute the respirable fraction. Six species of hardwood (beech, oak, ash, hornbeam, alder, and walnut), and three species of softwood (larch, pine, and spruce) were used in the research. While sanding the samples under the established laboratory conditions, the following were measured for two types of sandpapers (grit sizes P60 and P180): mean arithmetic particle size of dust and finest dust particles content (<10 µm). Based on the obtained results, we found that the largest dust particle sizes were obtained for alder, pine, and spruce; the smallest size of dust particles during sanding with both sandpapers was obtained for beech, hornbeam, oak, ash, larch, and walnut. The mean arithmetic particle sizes ranged from 327.98 µm for pine to 104.23 µm for hornbeam. The mean particle size of the dust obtained with P60 granulation paper was 1.4 times larger than that of the dust obtained with P180 granulation sandpaper. The content of the finest dust particles ranged from 0.21% for pine (P60 sandpaper) to 12.58% for beech (P180 sandpaper).The type of wood (hardwood or softwood) has a significant influence on the particle size and the content of the finest dust fraction.

Bark particle sizes and the modification of the physical properties of peat substrates

1999 ◽  
Vol 79 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Nsalambi V. Nkongolo ◽  
Jean Caron
Keyword(s):  
Particle Size ◽  
Plant Roots ◽  
Particle Sizes ◽  
Gas Diffusivity ◽  
Diffusivity Measurements ◽  
Air Supply ◽  
Wood Bark ◽  
Porosity Measurements ◽  
Coarse Gravel

The physical quality of peat mixes is in part related to the capacity of the substrate to store and supply air and water to plant roots. During manufacturing, the mixing of various substrate components modifies the substrate characteristics. The objective of this study was to assess the changes in air storage and supply properties caused by varying the particle size of the substrate components. The substrate was composed of 40% wood bark (WB), 50% peat, and 10% coarse gravel (volume basis). Wood bark particle size was varied in a first (0–2, 2–4, 4–8 and 8–25 mm) and a second (1–2, 2–4, 4–8 and 8–16 mm) experiment. When increasing bark particle sizes to 8–25 mm or 8–16 mm, air supply characteristics, as assessed with gas diffusivity measurements, decreased to 0.78 or 0.45 its value for the 2–4 or 1–2 mm average bark particle size. This occurred despite no significant changes in air storage, as assessed from air-filled porosity measurements. Key words: Gas diffusivity, pore tortuosity, air-filled porosity, peat lite mixes, peat substrates

Discrete Element Modeling of Scraping Process and Quantification of Powder Bed Quality for SLM

2020 ◽  
Author(s):  
Kuldeep Mandloi ◽  
Parth Amrapurkar ◽  
Harish P. Cherukuri
Keyword(s):  
Particle Size ◽  
Volume Fraction ◽  
Numerical Models ◽  
Discrete Element ◽  
Contact Model ◽  
Powder Particle Size ◽  
Particle Sizes ◽  
Powder Bed ◽  
Size And Shape

Abstract In selective laser melting (SLM) and selective laser sintering (SLS) additive manufacturing techniques, the powder spreading process plays a key role in the quality of the manufactured parts. Some of the important parameters that influence the quality of the powder bed are the powder particle size distribution, spreader-type (roller or blade), spreader speed, size and shape of the particles. In this work, we use the discrete element method to study the effect of these parameters on the quality of the powder bed. The interactions between the particles is modeled using Hertz-Mindlin contact model as well as Hertz-Mindlin with JKR contact model with the latter being used for studies of the effect of cohesiveness of particles on powder bed quality. The Dynamic Repose Angle (DRA) is used for validating the numerical models. Our studies differ from the previous studies in that we have introduced quantitative measures for powder bed quality in the form of Discretized Volume Fraction (DVF) and Particle Flow Rate (PFR) for the layering process. With the help of these quantities, we studied various factors that affect powder bed quality: cohesiveness of the particles, spreader shape, particle size and shape, and the distribution of particle sizes. Our results indicate that as DVF and PFR decrease and DRA increases, the potential for cavities and shifting defects increases due to increase in cohesiveness. Use of fixed particle size in the simulations leads to higher DRA than when a normal distribution of particle sizes is considered. Our results show that the roller geometry provides better bed quality as compared to the blade type geometry.

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