Simulation Method of Particle Size Scale for Fine Sand Model

2014 ◽  
Vol 580-583 ◽  
pp. 1878-1882
Author(s):  
Wan Li Liu ◽  
Xiao Fei Liu ◽  
Pei Jiu Yue

In sediment movable bed model, the basic similar conditions include the flow movement similar and the sediment movement similar. In water flow movement similar conditions, the velocity scale of the Freund's similarity and resistance similarity is inconsistency, and the flow resistance is the function of bed material grain size and flow intensity. In sediment movement similar, the particle size scale forms are not consistent too, and they are also related to the flow conditions, so the sediment partial size scale is difficult to determine. According to the research, the similar conditions can be focused on primary and secondary one, and put the primary one as the design basis. In view of the waterway regulation, the regulation flow discharge should be the design basis, others allowed a certain deviation; In the straight reach, resistance similarity should be the design basis, Freund's similarity allowed a certain deviation; In the bend reach, the Freund's similarity and resistance similarity should be simultaneously satisfied; For the bed load model, the incipient motion should meet similarity condition; The suspended sediment model should meet the sediment suspension similarity; For the non-uniform sediment, median particle size should be the design basis. According to the above principles, the sediment particle size scale can be determined.

2011 ◽  
Vol 20 (3) ◽  
pp. 443 ◽  
Author(s):  
Emmanuel J. Gabet ◽  
Andy Bookter

In this study, ash is analysed as a geological material; in particular, we focus on ash produced by the burning of Ponderosa pine, a conifer that is widespread throughout mountainous landscapes of western North America. One set of ash samples used in the analyses was collected from a wildfire site and another set was created in the laboratory. We found that the median particle size of the ash was in the fine sand to silt range with at least 25–50% of the particle size distribution in the appropriate range for maintaining debris flow behaviour. Measurements of the infiltration capacity of ash found values similar to fine sands, indicating that a layer of ash can reduce the infiltration capacity of coarse soils. The elemental composition of ashes analysed through inductively coupled plasma emission spectrometry was dominated by Ca, K, Mg, P, Mn, Fe and Al. X-ray diffraction analysis revealed the presence of calcite, quartz and feldspars in ashes created from a variety of fuels; fuel type and combustion temperature were found to have a dominant control on ash mineralogy. The results suggest that the elemental and mineral composition of ash could be used to identify dominant fuel sources and combustion temperatures.


1984 ◽  
Vol 21 (9) ◽  
pp. 1061-1066 ◽  
Author(s):  
Eric J. Schiller ◽  
A. Charles Rowney

Experiments were conducted to assess ways in which an imposed sediment load can affect the formation and final nature of an armoured bed. A flume loaded with a quartz aggregate of known composition was subjected to various sediment-laden flows of water to produce armoured beds. Characteristic parameters of the armoured beds were then compared.In general, it was found that the final armoured bed can be significantly altered by an imposed sediment load. As the size of the input sediment increased, the amount of bed material that was eroded, the resulting particle size of the bed, and the total roughness of the bed all decreased. The formation of bed forms was very important in this process. The trends observed in these experimental tests indicate that the presence or absence of upstream sediment sources has a direct influence on the resulting armoured layer.


2005 ◽  
Vol 284-286 ◽  
pp. 365-368 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama

The effect of different particle sizes on the flexural strength and microstructure of three different types of hydroxyapatite (HAp) powders was studied. The powder characteristics of laboratory synthesized HAp powder (Lab1 and Lab2) were obtained through a wet milling method, and the median particle size and the specific surface area of powders are different with the dryness period. The median particle sizes of Lab1 and Lab2 are 0.34 µm and 0.74 µm, and the specific surface areas of Lab1 and Lab2 are 38.01 m2/g and 19.77 m2/g. The commercial HAp had median particle size of 1.13 µm and specific surface area of 11.62m2/g. The different powder characteristics affected the slip characteristics, and the flexural strength and microstructure of the sintered porous HAp bodies are also different. The optimum value for the minimum viscosity in these present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were investigated. The flexural strengths of the porous HAp ceramics prepared by heating at 1200°C for 3 hrs in air were 17.59 MPa for Lab1 with a porosity of 60.48%, 10.51 MPa for Lab2 with a porosity of 57.75%, and 3.92 MPa for commercial HAp with a porosity of 79.37%.


2021 ◽  
Author(s):  
Igor M. Ivanov ◽  
Tatiana B. Pechurina ◽  
Nikolai G. Vengerovich ◽  
Mikhail A. Yudin ◽  
Aleksandr S. Nikiforov ◽  
...  

Samples of antiemetic drugs (ondansetronum, palonosetronum, metoclopramidum) in the form of powder for inhalation have been developed by the method of spray drying. The granulometric composition, hygroscopicity and aerodynamic distribution of aerosol particles of the drugs have been investigated. The dosage form of the powder for inhalation of antiemetics (ondansetronum and palonosetronum) in terms of its particle size distribution, hygroscopicity and content of the agent corresponds to those for inhalation using dry powder inhalers. In the study of the phase-dispersed composition of aerosol, ondansetronum and palonosetronum in the dosage form of powder for inhalation as part of the HandiHaler inhaler (at a flow rate of 60 l / min) showed high rates of the released dose up to 72-76%, respirable particle fraction (up to 5 m) up to 54 -56% and a mass median particle size of about 3 microns. Obtaining the inhaled form of metoclopramide requires optimization of the production method for receiving the product with acceptable pharmaceutical properties.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Punnaman Norrarat ◽  
Weerachart Tangchirapat ◽  
Smith Songpiriyakij ◽  
Chai Jaturapitakkul

This paper investigates the cement hydration, and the slag reaction contributes to the compressive strengths of mortars mixed with ground river sand (GRS) and ground-granulated blast furnace (GGBF) slag with different particle sizes. GRS (inert material) and GGBF slag (reactive material) were ground separately until the median particle sizes of 32 ± 1, 18 ± 1, and 5 ± 1 micron and used to replace Portland cement (PC) in large amount (40–60%) by weight of the binder. The results showed that, at the early age, the compressive strength obtained from the cement hydration was higher than that obtained from the slag reaction. The results of compressive strength also indicated that the GGBF slag content and particle size play important roles in the slag reaction at the later ages, whereas cement hydration is more prominent at the early ages. Although the results could be expected from the use of GGBF slag to replace PC in mortar or concrete, this study had presented the values of the compressive strength along with ages and the finenesses of GGBF slag that contributed from cement hydration and from GGBF slag reaction.


Author(s):  
Colin A. Booth ◽  
Michael A. Fullen ◽  
John Walden ◽  
Annie T. Worsley ◽  
Saulius Marcinkonis ◽  
...  

The use of mineral magnetic concentration parameters (χLF, χARM and SIRM) as a potential particle size proxy for soil samples collected from the Isle of Man (British Isles) is explored as an alternative means of normalizing particle size effects. Comparison of soil‐related analytical data by correlation analyses between each magnetic parameter and individual particle size classes (i.e. sand, silt and clay), more discrete intervals within classes (e.g. fine sand or medium silt) and cumulative size fractions (e.g. clay + fine silt) are reported. Both χLF and χARMparameters reveal significant (p < 0.05; n = 46), but relatively weak (rs = 0.297 and 0.369), associations with clay content, while χLF, χARM and SIRM parameters have no significant relationship with sand and silt content or any discrete or cumulative size fractions. Contrary to earlier research findings, this indicates that magnetic measurements are not always a suitable particle size proxy and it is only certain environments and/or specific settings that are appropriate for granulometric normalization by this technique. However, if future researchers working in other soil settings can identify a formal predictable relationship, the technique is known to offer a simple, reliable, rapid, sensitive, inexpensive and non‐destructive approach that could be a valuable particle size proxy for normalizing particle size effects in soil contamination studies. Santrauka Tyrimuose atskleistas mineralų magnetinių koncentracijos parametrų panaudojimas (χLF, χARM ir SIRM) kaip potencialiai alternatyvus metodas granuliometrinės sudėties nustatymo analizei Isle of Man (Britų salos) surinktiems dirvožemio pavyzdžiams tirti ir dalelių dydžio reiškiniui normalizuoti. Aprašytas su dirvožemiu susijusių analizinių duomenų palyginimas koreliacinių analizių būdu, t. y. tarp kiekvieno magnetizmo parametro ir atskirų dydžių dalelių frakcijų (t. y. smėlio, dulkių ir dumblo) ir tarpinių šių intervalų frakcijų (pavyzdžiui, smulkaus smėlio ar vidutinio rupumo dulkių) ir jungtinių frakcijų (pavyzdžiui, dumblo + smulkių dulkių). Tiek χLF, tiek χARM parametrai atskleidžia reikšmingas (p <0,05; n = 46), bet palyginti nereikšmingas (rs = 0,297 ir 0,369) ryšių asociacijas su dumblo kiekiu, o χLF, χARM ir SIRM parametrai neturi reikšmingų priklausomybių nuo smėlio ir dulkių kiekių, nei su atskiromis ar jungtinėmis dalelių dydžių frakcijomis. Priešingai ankstyvesniems tyrinėjimų rezultatams, tai rodo, kad magnetiniai matavimai ne visada yra tinkama alternatyva granuliometrinės sudėties analizei pakeisti ir tiktai tam tikroje, specifinėje aplinkoje yra tinkami granuliometrinei sudėčiai normalizuoti. Tačiau jei ateityje tyrėjai, tiriantys kitas dirvožemio savybes, nustatytų proporcingas prognozuojamas priklausomybes, šis matavimų metodas siūlo paprastą, patikimą, greitą, tikslų, nebrangų ir neardomąjį metodą, kuris galėtų būti vertinga granuliometrinės analizės alternatyva normalizuojant dalelių dydžio reiškinius studijuojant užterštus dirvožemius. Резюме Исследована возможность использования магнитных параметров (χLF, χARM и SIRM) как альтернативного потенциального метода для определения гранулометрического состава почв, отобранных в Isle of Man (Британские острова), и нормализирования эффекта по величине частиц. Описано сравнение связанных с почвой аналитических данных на основе метода корреляционного анализа, т. е. между каждым параметром магнетизма и частиц отдельных фракций (песок, пыль, глина) и промежуточных фракций этих интервалов (например, глина + мелкая пыль). Параметры как χLF, так и χARM показывают существенную (p <0.05; n = 46), однако сравнительно слабую (rs = 0.297 ir 0.369) связь с количеством пыли, в то время как параметры χLF, χARM и SIRM не имели существенной зависимости от количества глины и песчаных частиц как для отдельных, так и для смешанных фракций. В отличие от результатов предыдущих исследований данные результаты свидетельствуют о том, что магнитные измерения не всегда являются приемлемой альтернативой для замены метода определения гранулометрического состава и лишь в определенных специфических условиях могут применяться для этого. Если в будущем исследователи, изучающие другие свойства почвы, смогут установить пропорциональные прогнозируемые зависимости, этот магнитный метод измерения сможет применяться, так как он предлагает простой, достоверный, быстрый, точный, недорогой и неизменяющийся способ, который может быть альтернативой анализа гранулометрического состава с целью нормализации эффекта величины частиц при изучении загрязненных почв.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
André Eiermann ◽  
Samo Smrke ◽  
Loïc-Marco Guélat ◽  
Marco Wellinger ◽  
Anja Rahn ◽  
...  

Abstract The objective of this paper is to elucidate the variables that govern coffee extraction from single serve coffee capsules. The study was conducted on 43 Nespresso and Nespresso-compatible capsules of the same geometry, from all of which the coffee was extracted on the same machine. This allowed the link between a range of coffee and capsule (input) parameters with coffee brew (output) variables to be studied. It was demonstrated that the most efficient way to increase total dissolved solids in the brew is to use more coffee for extraction, and/or to grind the coffee more finely. However, grinding too finely can lead to excessive flow restriction. The most significant new insight from this study is the importance of the proportion of fines (particles smaller than 100 µm) regarding the capsule extraction dynamics. Capsules with a higher share of fines, for similar median particle size of the ground coffee, led to longer extraction times. General rules applicable for capsule coffee product development were established, although fine-tuning of parameters for successful capsule coffee extraction remains specific to production line and type of coffee.


Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 970 ◽  
Author(s):  
Bao Hoang Duong ◽  
Hoai Nam Truong ◽  
Quynh Anh Phan Nguyen ◽  
Thuong Nhan Nguyen Phu ◽  
Le Thi Hong Nhan

Low aqueous solubility and poor bioavailability of curcumin have limited its application in various fields. One approach to address this issue is to formulate a nanosuspension that incorporates curcumin, which has been previously shown to exhibit remarkably improved solubility in comparison with that of a bare compound. In this study, the preparation process of curcumin nanosuspension was optimized with a median particle size as the outcome. Gum arabic was used as a natural polymeric surfactant and the suspension was formulated using high speed homogenization. Optimization results, realized via a response surface methodology, showed that a minimum median particle size (8.524 µm) could be attained under the following conditions: curcumin:gum arabic ratio of 1:6 g/g; homogenization speed of 8300 rpm and homogenization time of 40 min. Under these conditions, the particle size of obtained suspension was shown to be consistent for around seven days without major aggregation. The homogenization process could be scaled up to five times in terms of suspension volume. TEM also showed that curcumin nanoparticles had a nearly spherical shape and homogeneous structure with a size range of 40–80 nm.


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