Stability of structural aggregates of dry soil

1950 ◽  
Vol 1 (3) ◽  
pp. 266 ◽  
Author(s):  
TJ Marshall ◽  
JP Quirk
Keyword(s):  
Size Distribution ◽  
Brittle Materials ◽  
Median Size ◽  
Coal Technology ◽  
Dry Soil ◽  
Natural Aggregates ◽  
The Stability ◽  
Surfaces Of Weakness

The stability of natural aggregates of dry soil has been examined by a drop-shatter method similar to that used in coal technology, The median size was determined after dropping from heights of 30, 60, 120, and 240 cm. The dropping procedure subdivides aggregates along surfaces of weakness into smaller natural units. The method has been used to help define the structure and consistence of various soils. The size distribution of fractured dry soil is in general given satisfactorily by the Rosin-Rammler relation for fractured brittle materials. The possibility of using Atterberg's steel wedge to measure the strength of natural aggregates was also examined.

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

scholarly journals Impactor Flux on the Pluto-Charon System

2009 ◽  
Vol 5 (S263) ◽  
pp. 98-101 ◽  
Author(s):  
Gonzalo C. de Elía ◽  
Romina P. Di Sisto ◽  
Adrián Brunini
Keyword(s):  
Size Distribution ◽  
Kuiper Belt ◽  
Primary Source ◽  
Mean Motion ◽  
Stability And Instability ◽  
The Stability ◽  
Mean Motion Resonance ◽  
Collisional Evolution

AbstractIn this work, we study the impactor flux on Pluto and Charon due to the collisional evolution of Plutinos.To do this, we develop a statistical code that includes catastrophic collisions and cratering events, and takes into account the stability and instability zones of the 3:2 mean motion resonance with Neptune. Our results suggest that if 1 Pluto-sized object is in this resonance, the flux of D = 2 km Plutinos on Pluto is ~4–24 percent of the flux of D = 2 km Kuiper Belt projectiles on Pluto. However, with 5 Pluto-sized objects in the resonance, the contribution of the Plutino population to the impactor flux on Pluto may be comparable to that of the Kuiper Belt. As for Charon, if 1 Pluto-sized object is in the 3:2 resonance, the flux of D = 2 km Plutinos is ~10–63 percent of the flux of D = 2 km impactors coming from the Kuiper Belt. However, with 5 Pluto-sized objects, the Plutino population may be a primary source of the impactor flux on Charon. We conclude that it is necessary to specify the Plutino size distribution and the number of Pluto-sized objects in the 3:2 Neptune resonance in order to determine if the Plutino population is a primary source of impactors on the Pluto-Charon system.

scholarly journals The Influence of Grain Size Distribution on the Hydraulic Gradient for Initiating Backward Erosion

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2644 ◽  
Author(s):  
Willem-Jan Dirkx ◽  
Rens Beek ◽  
Marc Bierkens
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Laboratory Experiments ◽  
Hydraulic Gradient ◽  
Concentrated Flow ◽  
Pipe Formation ◽  
Novel Method ◽  
Flow Through ◽  
The Stability

Backward erosion by piping is one of the processes that threaten the stability of river embankments in the Netherlands. During high river stages, groundwater flow velocities underneath the embankment increase as a result of the steepened hydraulic gradient. If a single outflow point exists or forms, the concentrated flow can entrain soil particles, leading to the formation of a subsurface pipe. The processes controlling this phenomenon are still relatively unknown due to their limited occurrence and because piping is a subsurface phenomenon. To study the initiation of piping, we performed laboratory experiments in which we induced water flow through a porous medium with a vertically orientated outflow point. In these experiments, we explicitly considered grain size variations, thus adding to the existing database of experiments. Our experiments showed that the vertical velocity needed for the initiation of particle transport can be described well by Stokes’ law using the median grain size. We combine this with a novel method to relate bulk hydraulic conductivity to the grain size distribution. This shows that knowledge of the grain size distribution and the location of the outflow point are sufficient to estimate the hydraulic gradient needed to initiate pipe formation in the experiment box.

A model for characterizing dry soil aggregate size distribution

CATENA ◽  
2021 ◽  
Vol 198 ◽  
pp. 105018
Author(s):  
Zhongling Guo ◽  
Chunping Chang ◽  
Xueyong Zou ◽  
Rende Wang ◽  
Jifeng Li ◽  
...  
Keyword(s):  
Size Distribution ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Aggregate Size Distribution ◽  
Dry Soil

The determination of the size distribution of soil clods and crumbs

1940 ◽  
Vol 30 (2) ◽  
pp. 210-234 ◽  
Author(s):  
E. W. Russell ◽  
R. V. Tamhane
Keyword(s):  
Size Distribution ◽  
Maximum Amount ◽  
Moist Soil ◽  
Personal Factor ◽  
Water Stable Aggregates ◽  
Dry Soil ◽  
Pre Treatment ◽  
The Individual ◽  
And Training

1. It is possible to determine the size distribution of clods in the field by simple sieving of the soil without any pre-treatment provided the soil is not too wet. There is a personal factor involved in the sieving, but with care and training this will not affect comparisons of results obtained by that person. If the soil is too wet the individual clods smaller than 3 mm. stick together on the 3 mm. sieve. This sticking together is first apparent on the 3 mm. sieve but may become appreciable on the ¼ in. (6 mm.) sieve. No certain way was found for overcoming this difficulty.2. There appears to be no best method for determining the size distribution of the soil crumbs, i.e. of the water-stable aggregates in the soil. The method and the technique must be chosen so as to give the maximum amount of useful information. If an appreciable proportion of the crumbs are larger than ½ mm., a water-sieving method is practically essential.3. The method of wetting to be used can only be chosen from a consideration of what information is wanted. If possible it would be desirable for general purposes to use a very slow or a vacuum wetting technique and a very rapid wetting technique such as wetting the soil by immersion in water.4. The decision whether air-dry or field-moist soil should be used depends entirely on the information needed. For general purposes the use of air-dry soil is recommended.

Using Two Sieves to Characterize Dry Soil Aggregate Size Distribution

1987 ◽  
Vol 30 (1) ◽  
pp. 0162-0165 ◽  
Author(s):  
L. J. Hagen ◽  
E. L. Skidmore ◽  
D. W. Fryrear
Keyword(s):  
Size Distribution ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Aggregate Size Distribution ◽  
Dry Soil

A Study of Intravenous Emulsion Compatibility: Effects of Dextrose, Amino Acids, and Selected Electrolytes

1981 ◽  
Vol 15 (3) ◽  
pp. 184-193 ◽  
Author(s):  
Curtis D. Black ◽  
Nicholas G. Popovich ◽  
Myrella Roy
Keyword(s):  
Amino Acids ◽  
Size Distribution ◽  
Emulsion Stability ◽  
Divalent Cations ◽  
Linear Regression Analysis ◽  
Stability Loss ◽  
Ionic Concentration ◽  
Oil Emulsion ◽  
Globule Size ◽  
The Stability

Microscopic and electronic counting procedures as well as visual observations for creaming and flocculation were employed to quantitatively and qualitatively measure the effects of dextrose, amino acids, and various mono- and di-valent cations on the globule size distribution of the soybean oil emulsion 10%, Intralipid®. A linear regression analysis was demonstrated to successfully profile much of the stability data. Results indicated that divalent cations caused flocculation in the emulsion's internal phase immediately upon or shortly after the addition of their salts. The rate and extent of flocculation intensified with increasing ionic concentration. Amino acids, apparently acting at the oil/water interface, delayed divalent cation-induced flocculation; however, they did not prevent emulsion stability loss. The addition of dextrose 5% or 12.5% brought about a reduction of emulsion pH and significant globule coalescence 72 hours after admixture. Monovalent cations (i.e., Na+, K+) induced a progressive loss of emulsion stability over the 72-hour course of the experiments, the effect a function of ionic concentration. From the data, a model has been generated to predict significant changes ( p < 0.05) in Intralipid's® globule size distribution upon addition of solute and exposure to room temperature. Further recommendations of solute admixture with the intravenous emulsion are also included.

scholarly journals On the sub-micron aerosol size distribution in a coastal-rural site at El Arenosillo Station (SW – Spain)

2011 ◽  
Vol 11 (21) ◽  
pp. 11185-11206 ◽  
Author(s):  
M. Sorribas ◽  
B. A. de la Morena ◽  
B. Wehner ◽  
J. F. López ◽  
N. Prats ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Formation ◽  
Rural Site ◽  
Aerosol Size Distribution ◽  
Land Breeze ◽  
Air Masses ◽  
Desert Dust ◽  
Median Size ◽  
The Mean ◽  
Marine Air

Abstract. This study focuses on the analysis of the sub-micron aerosol characteristics at El Arenosillo Station, a rural and coastal environment in South-western Spain between 1 August 2004 and 31 July 2006 (594 days). The mean total concentration (NT) was 8660 cm−3 and the mean concentrations in the nucleation (NNUC), Aitken (NAIT) and accumulation (NACC) particle size ranges were 2830 cm−3, 4110 cm−3 and 1720 cm−3, respectively. Median size distribution was characterised by a single-modal fit, with a geometric diameter, median number concentration and geometric standard deviation of 60 nm, 5390 cm−3 and 2.31, respectively. Characterisation of primary emissions, secondary particle formation, changes to meteorology and long-term transport has been necessary to understand the seasonal and annual variability of the total and modal particle concentration. Number concentrations exhibited a diurnal pattern with maximum concentrations around noon. This was governed by the concentrations of the nucleation and Aitken modes during the warm seasons and only by the nucleation mode during the cold seasons. Similar monthly mean total concentrations were observed throughout the year due to a clear inverse variation between the monthly mean NNUC and NACC. It was related to the impact of desert dust and continental air masses on the monthly mean particle levels. These air masses were associated with high values of NACC which suppressed the new particle formation (decreasing NNUC). Each day was classified according to a land breeze flow or a synoptic pattern influence. The median size distribution for desert dust and continental aerosol was dominated by the Aitken and accumulation modes, and marine air masses were dominated by the nucleation and Aitken modes. Particles moved offshore due to the land breeze and had an impact on the particle burden at noon, especially when the wind was blowing from the NW sector in the morning during summer time. This increased NNUC and NAIT by factors of 3.1 and 2.4, respectively. Nucleation events with the typical "banana" shape were characterised by a mean particle nucleation rate of 0.74 cm−3 s−1, a mean growth rate of 1.96 nm h−1 and a mean total duration of 9.25 h (starting at 10:55 GMT and ending at 20:10 GMT). They were observed for 48 days. Other nucleation events were identified as those produced by the emissions from the industrial areas located at a distance of 35 km. They were observed for 42 days. Both nucleation events were strongly linked to the marine air mass origin.

scholarly journals KARAKTERISTIK MARSHALL QUOTIENT PADA HOT MIX ASPHALT MENGGUNAKAN AGREGAT ALAM SUNGAI OPAK

2019 ◽  
Vol 15 (2) ◽  
pp. 84-91
Author(s):  
Maris Setyo Nugroho
Keyword(s):  
Hot Mix Asphalt ◽  
Road Construction ◽  
National Standard ◽  
Test Results ◽  
Quality Testing ◽  
Asphalt Content ◽  
Natural Aggregates ◽  
The Stability ◽  
Asphalt Quality

 ABSTRACTThe purpose of this study is to determine the Marshall Quotient (MQ) value of hot mix asphalt (HMA), which uses natural aggregates from the Opak river. In addition to the MQ value in this study also examines the value of stability and flow in concrete asphalt mixtures with asphalt content of 6.5%. The research method used was an experimental method in the JPTSP FT UNY road construction laboratory. The testing standard used refers to the Indonesian National Standard (SNI). In addition to testing Marshall values, preliminary testing is also carried out to determine the quality of the material used. Material testing includes aggregate quality testing and asphalt quality testing. Based on the test results, the stability, flow and MQ values were 1177.01 kg, 3.20 mm and 384.05 kg/mm respectively. When compared with the requirements in the RSNI 03-1737-1989, only the flow values do not meet the requirements.Keywords: hot mix asphalt (HMA), stability, flow, marshall quotient ABSTRAK Penelitian ini bertujuan untuk mengetahui nilai Marshall/Marshall Quotient (MQ)dari campuran aspal panas/hot mix asphalt (HMA), yang menggunakan agregat alami dari kali Opak. Selain nilai MQ pada penelitian ini juga mengkaji nilai stabilitas dan kelelehan (flow) pada campuran aspal beton dengan kadar aspal 6,5%. Metode penelitian yang digunakan yaitu metode eksperimental di laboratorium konstruksi jalan JPTSP FT UNY. Standar pengujian yang digunakan mengacu Standar Nasional Indonesia (SNI). Selain pengujian nilai Marshall juga dilakukan pengujian pendahuluan untuk mengetahui mutu material yang digunakan. Pengujian material yang dilakukan meliputi pengujian mutu agregat dan pengujian mutu aspal yang digunakan untuk campuran aspal beton. Bersarkan hasil pengujian diperoleh nilai stabilitas, kelelehan, dan nilai Marshall berturut-turut sebesar 1171,01 kg, 3,20 mm, dan 384,05 kg/mm. Jika dibandingkan dengan persyaratan nilai stabilitas, kelelehan, dan nilai marshal yang tercantum pada RSNI 03-1737-1989, hanya nilai kelehan saja yang tidak memenuhi persyaratan. Kata kunci: hot mix asphalt (HMA), stabilitas, kelelehan, nilai marshall

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