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

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 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 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.

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.

Lime Brust of Sintering Bricks of Purple Sandy Shale: the Effect of Limestone Particle Size

2011 ◽  
Vol 250-253 ◽  
pp. 46-49
Author(s):  
Zhi Gang Feng ◽  
Zhen Ping Tang ◽  
Hui Juan Li
Keyword(s):  
Particle Size ◽  
Hunan Province ◽  
Particle Sizes ◽  
Sintering Process ◽  
Critical Content ◽  
Production Practice ◽  
Sandy Shale ◽  
Free Cao ◽  
The Relationship

Simulating current sintering process in local brickkilns, Hengyang region, Hunan Province, China, at 800°C, througt indoor sintering experiment on a series of brick samples of purple sandy shale, in which particle sizes of limestone are >-1Φ, >0Φ, >1Φ, >2Φ, >3Φ and >4Φ, respectively, it is concluded that the following: (1) Limestone granularity is a crucial factor affecting the quality of sintering bricks of purple sandy shale. Under different particle sizes, the critical content of limestone causing lime brust of sintering bricks is distinct, and lowers with the increasing in limestone granularity. (2) When limestone granularity is different, its impact way on the quality of sintering bricks is also distinct. The more coarse limestone granularity is, the more concentrative the swelling stress produced by the hydration of free CaO is, the more easily lime brust occurs. On the contrary, the more fine limestone granularity is, the more dispersive the swelling stress is, there is the more help to reduce or eliminate the occurrence of lime brust. (3) In view of the relationship between limestone granularity and the critical content of limestone giving rise to lime brust of sintering bricks, the production practice can be effectively guided.

scholarly journals Investigation of organic desulfurization additives affecting the calcium sulfate crystals formation

2017 ◽  
Vol 23 (2) ◽  
pp. 161-167
Author(s):  
Lina Lv ◽  
Rui Gao ◽  
Jianbin Yang ◽  
Zhigang Shen ◽  
Yanbo Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Moisture Content ◽  
Calcium Sulfate ◽  
Sodium Citrate ◽  
Crystal Morphology ◽  
Particle Sizes ◽  
Experimental Conditions ◽  
Moisture Contents

In the study, the optimal experimental conditions for gypsum crystals formation were 323 K, 300 rpm stirring speed. The major impurities of Mg2+, Al3+ and Fe3+ were found to inhibit calcium sulfate crystals formation. Fe3+ caused the strongest inhibition, followed by Mg2+ and Al3+. The influence of desulfurization additives on the gypsum crystals formation was explored with the properties of moisture content, particle size distribution and crystal morphology. The organic desulfurization additives of adipic acid, citric acid, sodium citrate and benzoic acid were investigated. Citric acid and sodium citrate were found to improve the quality of gypsum. Moisture contents were reduced by more than 50%, gypsum particle sizes were respectively enlarged by 9.1 and 22.8%, induction time extended from 4.3 (blank) to 5.3 and 7.8 min, and crystal morphology trended to be thicker.

scholarly journals Effect of Sawdust Particle Size on Physical, Mechanical, and Energetic Properties of Pinus durangensis Briquettes

2021 ◽  
Vol 11 (9) ◽  
pp. 3805
Author(s):  
Christian Osvaldo Zepeda-Cepeda ◽  
José Rodolfo Goche-Télles ◽  
Celina Palacios-Mendoza ◽  
Oswaldo Moreno-Anguiano ◽  
Víctor Daniel Núñez-Retana ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Density ◽  
Impact Resistance ◽  
Resistance Index ◽  
Physical Property ◽  
Calorific Value ◽  
Particle Sizes ◽  
Energetic Properties ◽  
Simplex Lattice

Particle size is a physical property that sometimes limits the quality of briquettes, so it is recommended to use different sizes in mixtures for their manufacture. The objective of this research was to evaluate the effect of different particle sizes of sawdust in mixtures on some physical, mechanical, and energetic properties of briquettes made from Pinus durangensis sawdust, as well as set the ranges within the appropriate values found to obtain desired values. Three particle sizes were established (large, medium, and small), and 10 mixtures were prepared using different percentages of each particle classification. The particle density, volumetric swelling, compressive strength, impact resistance index (IRI), and gross calorific value of the briquettes were evaluated. For the determination of optimal mixtures, the surface response methodology was used under a three-factor simplex-lattice model. The particle density values were in the range 0.92 to 1.02 g cm−3 and the volumetric swelling was 0.96 to 3.9%. The highest resistance to compression was 37.01 N mm−1, and the IRI was found in the range of 53 to 107%. The gross calorific values were from 19.35 to 21.63 MJ kg−1. The selection of different particle sizes for the mixtures increases the quality of the briquettes.

scholarly journals Effect of Zn-Rich Wheat Bran With Different Particle Sizes on the Quality of Steamed Bread

2021 ◽  
Vol 8 ◽  
Author(s):  
Huinan Wang ◽  
Anfei Li ◽  
Lingrang Kong ◽  
Xiaocun Zhang
Keyword(s):  
Particle Size ◽  
Wheat Bran ◽  
Pasting Properties ◽  
Control Group ◽  
Particle Sizes ◽  
Sensory Score ◽  
Zn Content ◽  
Steamed Bread ◽  
Addition Level

Bran is the main by-product of wheat milling and the part of the grain with the highest Zn content. We investigated the effects of the particle sizes (coarse, D50 = 375.4 ± 12.3 μm; medium, D50 = 122.3 ± 7.1 μm; and fine, D50 = 60.5 ± 4.2 μm) and addition level (5–20%) of Zn-biofortified bran on the quality of flour and Chinese steamed bread. It was studied to determine if the Zn content of steamed bread could be enhanced without deleterious effects on quality. Dough pasting properties, such as peak viscosity, trough viscosity, final viscosity, breakdown, and setback, decreased significantly as the bran addition level was increased from 5 to 20% but did not significantly differ as a result of different bran particle sizes. Bran incorporation significantly increased hardness, gumminess, chewiness, and adhesiveness, whereas the springiness, cohesiveness, and specific volume of steamed bread decreased with the increase in bran addition. The optimal sensory score of steamed bread samples in the control and Zn fertilizer groups were obtained under 5% bran addition resulting in comparable flavor, and texture relative to control. Meanwhile, the Zn content of the steamed bread in the Zn fertilizer group was 40.2 mg/kg, which was 55.8% higher than that in the control group. Results indicated that adding the appropriate particle size and amount of bran would be an effective and practical way to solve the problem of the insufficient Zn content of steamed bread.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

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