INFLUENCE OF AGGREGATE DIAMETER, SURFACE AREA AND ANTECEDENT WATER CONTENT ON THE DISPERSIBILITY OF CLAY

1990 ◽  
Vol 70 (4) ◽  
pp. 655-671 ◽  
Author(s):  
B. D. KAY ◽  
A. R. DEXTER
Keyword(s):  
Water Content ◽  
Surface Area ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Specific Area ◽  
Unit Surface Area ◽  
Surface Areas ◽  
Fallow Soil ◽  
Unit Surface

The percentages of spontaneously dispersed clay, Ms, and mechanically dispersed clay, Mm, in a suspension of a given ionic strength were hypothesized to be controlled by the specific area of exposed aggregate surfaces and the dispersibility of clay per unit specific aggregate surface area. This hypothesis was evaluated using different sized aggregates collected in 1988 from wheat-fallow and continuous pasture rotations established in 1925 on a red-brown earth in southern Australia. Aggregates which were initially air-dry were wetted to matric water potentials ranging from −10 to −0.3 kPa, then placed in distilled water and Ms and Mm measured. Ms increased, as hypothesized, with increasing surface area of aggregates. However, the spontaneously dispersed clay per unit surface area of aggregates increased with increasing size of aggregates and increasing antecedent soil water content. The effect of water content was greatest in the larger aggregates of the less stable wheat-fallow soil. Mm was approximately 12 times larger than Ms and increased with increasing initial aggregate size and increasing antecedent water content. The sensitivity of Mm to water content was greatest on the least stable soil. Calculations showed that the higher values of Mm on unstable soils were due to both larger exposed aggregate surface areas and higher dispersibility of the clay on these surfaces. Keywords: Soil structure, aggregate stability, dispersion

scholarly journals Mpemba Effect- the Effect of Time

2021 ◽  
Author(s):  
Jianan Wang
Keyword(s):  
Gravitational Field ◽  
Surface Area ◽  
Time Effect ◽  
Light Quantum ◽  
Unit Surface Area ◽  
Heat Flows ◽  
Unit Surface ◽  
Average Wavelength ◽  
Nature Of Time ◽  
The Relationship

This paper draws the following conclusions on the nature of time by analyzing the relationship between time and speed, the relationship between time and gravitational field, the gravitational redshift of the photon, and the black-body radiation theorem: Time on an object is proportional to the amount of energy flowing out (or in) per unit time (observer’s time) per unit surface area of the object. When an object radiates energy outward: t'=μB(T) =μσT 4=μnhν/st Where t’ is the time on the object, μ is a constant, B(T) is the radiosity，the total energy radiated from the unit surface area of the object in unit time (observer’s time), σ is the Stefan-Boltzmann constant, T is the absolute temperature, n is the number of the photons radiated, ν is the average frequency of the photons radiated, s is the surface area of the object and t is the time on the observer. When the object radiates energy outward, the higher the energy density of the space (for example the stronger the gravitational field of the space), the smaller the radiosity B(T) of the object in the space, the longer the average wavelength of the light quantum emitted by the object, the slower the time on the object, the longer the life of the system. When the object radiates energy outward, the faster the object moves relative to the ether, the higher the energy density of the local space in which the object is located, the smaller the radiosity B(T) of the object, the longer the average wavelength of the light quantum radiated by the object, the slower the time on the object, and the longer the life of the system. When the object radiates energy outward, the higher the temperature of the object, the greater the object's radiosity B(T), the shorter the average wavelength of the light quantum radiated by the object, the faster the time on the object, and the shorter the life of the system. Applying the above conclusions about the nature of time, the author analyzes the Mpemba effect and the inverse Mpemba effect, and reaches the following conclusion: the Mpemba effect is the time effect produced when heat flows from objects into space, and the "inverse" Mpemba effect is the time effect produced when heat flows from space into objects.

Long-term experimental study of the aquatic plant system for polluted river water

2002 ◽  
Vol 46 (11-12) ◽  
pp. 217-224 ◽  
Author(s):  
K. Sato ◽  
H. Sakui ◽  
Y. Sakai ◽  
S. Tanaka
Keyword(s):  
Surface Area ◽  
Aquatic Plant ◽  
Aquatic Macrophyte ◽  
Unit Surface Area ◽  
Artificial Wetlands ◽  
Polluted River ◽  
Plant System ◽  
Unit Surface ◽  
Experimental Facilities

Water purification using artificial wetlands and aquatic macrophyte is attracting attention as a purification technology that can create rich ecosystems while imposing a minimal load on the environment. Because an aquatic plant system requires a large surface area, design specifications and maintenance methods that can obtain the optimum purification effect per unit surface area must be established. Large experimental facilities have been constructed beside a polluted river flowing into Lake Kasumigaura and have been used for a three-year experiment using several kinds of aquatic plants. This report summarizes the characteristics and the design load of the aquatic plant system based on this study and results from other aquatic plant facilities.

Effects of moisture condition and freeze/thaw cycles on surface soil aggregate size distribution and stability

2012 ◽  
Vol 92 (3) ◽  
pp. 529-536 ◽  
Author(s):  
Enheng Wang ◽  
Richard M. Cruse ◽  
Xiangwei Chen ◽  
Aaron Daigh
Keyword(s):  
Water Content ◽  
Size Distribution ◽  
Surface Soil ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Moisture Condition ◽  
Freeze Thaw ◽  
Aggregate Size Distribution ◽  
Disturbed Soil

Wang, E., Cruse, R. M., Chen, X. and Daigh, A. 2012. Effects of moisture condition and freeze/thaw cycles on surface soil aggregate size distribution and stability. Can. J. Soil Sci. 92: 529–536. Freeze/thaw cycles can affect soil aggregate stability, which in turn impacts wind and water erosion. The objectives of this laboratory study were: (1) to determine the effect of variable freeze/thaw cycles and soil water conditions on aggregate size distribution and stability; and (2) to evaluate differences in aggregate size distribution and stability between disturbed soil and undisturbed soil cores as affected by freeze/thaw cycles and soil water conditions. Surface soil was collected before freezing in late fall of 2009. Aggregates isolated from disturbed soil or intact soil cores were subjected to a factorial combination of 3 gravimetric water content treatments: 0.15 m3 m−3, 0.23 m3 m−3 or 0.30 m3 m−3, and 3 freeze/thaw treatments: 0, 3, or 9 cycles. A freeze/thaw cycle involved soil freezing at –10∘C for 24 h, followed by thawing at 5∘C for 24 h. Most aggregate size classes were affected significantly (P<0.05) by freeze/thaw cycles except for wet-sieved aggregates >5 mm. Dry-sieved aggregates were relatively more sensitive to the freeze/thaw treatment than wet-sieved aggregates. The mean weight diameter (MWD) of dry-sieved aggregates was significantly (P<0.05) greater at 0.30 m3 m−3 than 0.15 m3 m−3 water content, but the opposite trend was observed for MWD of wet aggregates and aggregate stability. There was a significant (P<0.05) response of the MWD in dry-sieved aggregates to the interactive freeze/thaw×water content effect that differed for aggregates obtained from disturbed soil and those in the undisturbed soil core, but not for the MWD of wet-sieved aggregates and aggregate stability.

Tillage-induced changes to soil structure and organic carbon fractions in New Zealand soils

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 465 ◽  
Author(s):  
T. G. Shepherd ◽  
S. Saggar ◽  
R. H. Newman ◽  
C. W. Ross ◽  
J. L. Dando
Keyword(s):  
Organic Carbon ◽  
Size Distribution ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Aggregate Size Distribution ◽  
Binding Agents ◽  
Rate Of Decline ◽  
Humic Soil

The effects of increasing cropping and soil compaction on aggregate stability and dry-sieved aggregate-size distribution, and their relationship to total organic C (TOC) and the major functional groups of soil organic carbon, were investigated on 5 soils of contrasting mineralogy. All soils except the allophanic soil showed a significant decline in aggregate stability under medium- to long-term cropping. Mica-rich, fine-textured mineral and humic soils showed the greatest increase in the mean weight diameter (MWD) of dry aggregates, while the oxide-rich soils, and particularly the allophanic soils, showed only a slight increase in the MWD after long-term cropping. On conversion back to pasture, the aggregate stability of the mica-rich soils increased and the MWD of the aggregate-size distribution decreased, with the humic soil showing the greatest recovery. Aggregate stability and dry aggregate-size distribution patterns show that soil resistance to structural degradation and soil resilience increased from fine-textured to coarse-textured to humic mica-rich soils to oxide-rich soils to allophanic soils. Coarse- and fine-textured mica-rich and oxide-rich soils under pasture contained medium amounts of TOC, hot-water soluble carbohydrate (WSC), and acid hydrolysable carbohydrate (AHC), all of which declined significantly under cropping. The rate of decline varied with soil type in the initial years of cropping, but was similar under medium- and long-term cropping. TOC was high in the humic mica-rich and allophanic soils, and levels did not decline appreciably under medium- and long-term cropping. 13C-nuclear magnetic resonance evidence also indicates that all major functional groups of soil organic carbon declined under cropping, with O-alkyl C and alkyl C showing the fastest and slowest rate of decline, respectively. On conversion back to pasture, both WSC and AHC returned to levels originally present under long-term pasture. TOC recovered to original pasture levels in the humic soil, but recovered only to 60–70% of original levels in the coarse- and fine-textured soils. Aggregate stability was strongly correlated to TOC, WSC, and AHC (P < 0.001), while aggregate-size distribution was moderately correlated to aggregate stability (P < 0.01) and weakly correlated to AHC (P < 0.05). Scanning electron microscopy indicated a loss of the binding agents around aggregates under cropping. The effect of the loss of these binding agents on soil structure was more pronounced in mica-rich soils than in oxide-rich and allophanic soils. The very high aggregate stabilities of the humic soil under pasture was attributed to the presence of a protective water-repellent lattice of long-chain polymethylene compounds around the soil aggregates.

scholarly journals The kinetics of influenza-virus adsorption on iron oxide in the process of viral purification and concentration

1971 ◽  
Vol 69 (1) ◽  
pp. 27-33 ◽  
Author(s):  
N. M. Larin ◽  
P. H. Gallimore
Keyword(s):  
Iron Oxide ◽  
Surface Area ◽  
Influenza A ◽  
Large Scale ◽  
Multiple Equilibria ◽  
Unit Surface Area ◽  
Fixed Temperature ◽  
Virus Adsorption ◽  
Significant Difference ◽  
Unit Surface

SUMMARYThis paper reports a study carried out to clarify the mechanisms involved in adsorption of influenza A and B viruses on iron oxide. Accordingly, the amounts of virus that are adsorbed from virus suspensions of varying concentrations per unit surface area of magnetic or non-magnetic oxide at fixed temperature and time have been determined. The principles involved are clearly the same as those involved in multiple equilibria during the interaction of particles with a large number of combining sites with different intrinsic affinity. Consequently, the amount of virus that is adsorbed per unit mass of iron oxide depends on the size of the adsorbent area, not on its magnetic property. Owing to a significant difference between the affinities of influenza A and B particles for the binding sites on iron oxide, unit surface area of the adsorbent is invariably capable of adsorbing significantly greater amounts of influenza A than B particles. The practical implications of these findings are that a better understanding of the mechanisms involved in virus adsorption on iron oxide will permit a more efficient separation of virus particles from impurities. The simplicity and the rapidity of the technique and the cheapness of the equipment required suggest that the iron oxide method is of great value for both small- or large-scale viral purification, whether it is used as a single step procedure or as a primary step followed by zonal separation.

scholarly journals Beç Tavuklarında (Numida meleagris) Yumurta Şekil İndeksinin Yumurta Kalitesine Etkileri

2016 ◽  
Vol 4 (9) ◽  
pp. 758 ◽  
Author(s):  
Sezai Alkan ◽  
Taki Karslı ◽  
İsmail Durmuş ◽  
Kemal Karabağ
Keyword(s):  
Surface Area ◽  
Egg Quality ◽  
Shape Index ◽  
Quality Characteristics ◽  
Unit Surface Area ◽  
Egg Volume ◽  
Egg Weight ◽  
Egg Shape ◽  
Unit Surface ◽  
Haugh Unit

The aim of this study was to investigated the effects of the egg shape index on egg quality characteristics in Guinea fowl. For this, the eggs were classified in terms of egg shape index, as ≤ 75, < 76 -77 > and ≥ 78. A total of 100 Guinea fowl eggs were evaluated to determine the egg quality traits ( egg weight, eggshell thickness, eggshell surface area, eggshell weight per unit surface area, eggshell ratio, albumen index, albumen ratio, yolk index, yolk ratio, yolk/albumen ratio, haugh unit and egg volume). In this study, eggshell thickness, eggshell weight per unit surface area, eggshell ratio, albumen index, albumen ratio, yolk index, yolk ratio, yolk/albumen ratio and haugh unit were not significantly affected by egg shape index groups. Whereas egg weight, eggshell surface area and egg volume were significantly affected by egg shape index groups. At the same time, there were found significant relationship between the egg shape index and egg quality traits. Egg shape index was found to be an important factor affecting the egg quality characteristics.

scholarly journals Free Oscillations of the Earth Climate System: A Theory of the 100 kyr Climate Cycle

1990 ◽  
Vol 14 ◽  
pp. 346
Author(s):  
R.M. MacKay ◽  
M.A.K. Khalil
Keyword(s):  
Surface Area ◽  
Nonlinear Differential Equations ◽  
Radiation Balance ◽  
Unit Surface Area ◽  
Ocean Temperature ◽  
Free Oscillations ◽  
The Earth ◽  
Climate Cycle ◽  
Unit Surface ◽  
The Mean

A physically plausible theory of the 100 kyr climate cycle is proposed. Free oscillations between the mean ocean temperature and the marine ice-margin colatitude are shown to exist without requiring orbital forcing. It is shown that the curvature of the Earth causes two effects: (1) as the marine ice margin grows towards the equator, the net emmision of radiation (solar and terrestrial) per unit surface area increases; and (2) as the poleward extent of the ocean decreases, the net absorption of radiation per unit surface area increases. These radiation balance considerations, included with a realistic meridional transport of energy from the ocean to the marine-ice region and an atmospheric feedback process enhancing the ocean warming, are combined to form two nonlinear differential equations coupling the mean ocean temperature with the marine-ice margin colatitude. Using physically realistic parameters we are able to reproduce the major features of the 100 kyr climate cycle. This can be seen from Figure I which shows the δ18O record as given by Imbrie and others (1984), plotted against the model output. In addition we have found that the parameters used to obtain the general features of the ice-volume record also predict temperature “spikes” (1 to 2 K. above average) of relatively short duration (5 to 10 kyr) in the mean ocean temperature. We find that there is good qualitative agreement between the model's predicted mean ocean temperature and the estimation of summer sea-surface temperature at RC11-120 presented by Martinson and others (1987).

Persistent improvements in the structure and hydraulic conductivity of a Ferrosol due to liming

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 218 ◽  
Author(s):  
J. M. Kirkham ◽  
B. A. Rowe ◽  
R. B. Doyle
Keyword(s):  
Hydraulic Conductivity ◽  
Organic Carbon ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Soil Surface ◽  
Penetration Resistance ◽  
Organic C ◽  
Soil Penetration Resistance ◽  
Wet Aggregate Stability

Changes in the soil structure and hydraulic conductivity of an Acidic Red Ferrosol were measured in a long-term (1968–2003) fertiliser experiment on pasture in north-western Tasmania, Australia. Studies were initiated following observations of both softer soil surface and cracking on plots that had received 15 t/ha of ground agricultural limestone. Liming decreased penetration resistance and increased hydraulic conductivity. These structural improvements were associated with increased mean dry aggregate size, a small increase in wet aggregate stability, higher exchangeable calcium levels, and increased plant growth, but a 9% decrease in total soil organic carbon in the surface 50 mm. This decrease in organic carbon was not associated with deterioration in soil structure, as may have been anticipated. This was probably because total organic C was still 82 g/kg on unlimed plots. Decreases in soil penetration resistance due to liming increased the likelihood of pugging from livestock but may improve ease of tillage. This research demonstrates that liming can improve the structure of a well-aggregated Ferrosol as well as its previously reported effects of increasing soil pH and yields of pasture and barley despite decreasing organic C.

scholarly journals Spatial Statistics of the Sea Surface in Fetch-Limited Conditions

2011 ◽  
Vol 41 (10) ◽  
pp. 1821-1841 ◽  
Author(s):  
Leonel Romero ◽  
W. Kendall Melville
Keyword(s):  
Surface Area ◽  
Spatial Information ◽  
Length Distribution ◽  
Second Order ◽  
Joint Probability Distribution ◽  
Unit Surface Area ◽  
Large Wave ◽  
Analytical Approximations ◽  
Unit Surface ◽  
Wave Heights

Abstract An analysis of airborne wave observations collected in the Gulf of Tehuantepec is presented. The data include lidar measurements of the surface displacement as a function of two horizontal dimensions in fetch-limited conditions, with fetches between 20 and 500 km and winds between 10 and 20 m s−1. The spatial data have an advantage over the commonly used single-point time series measurements, allowing direct estimates of the wavelength and wave slope, including spatial information such as the lengths of crests exceeding various thresholds. This study presents an analysis of several statistical wind wave parameters, including the joint probability distribution function (pdf) of wave amplitudes and wavelengths; the pdf of wave heights, wavenumber vectors, and wave slopes; as well as the statistics of the lengths of crests exceeding threshold wave heights and slopes. The empirical findings from the lidar data are compared against analytical theories in the literature, including some that had not been tested previously with field data such as the work by M. S. Longuet-Higgins describing the length of contours surrounding large wave heights per unit surface area. The effect of second-order nonlinearities on the distribution of crest lengths per unit surface area is investigated with analytical approximations and stochastic numerical simulations from computed directional wavenumber spectra. The results show that second-order nonlinearities can increase the crest-length distribution of large waves by a factor of 2 or more.

Inhomogeneity of ventilatory unit volume and its effects on reactive gas uptake

1991 ◽  
Vol 70 (5) ◽  
pp. 2193-2205 ◽  
Author(s):  
R. R. Mercer ◽  
S. Anjilvel ◽  
F. J. Miller ◽  
J. D. Crapo
Keyword(s):  
Oxygen Uptake ◽  
Surface Area ◽  
Unit Volume ◽  
Unit Surface Area ◽  
Vascular Perfusion ◽  
Gas Uptake ◽  
Unit Surface ◽  
Reactive Gases ◽  
Gas Volume ◽  
Reactive Gas

This study addressed the question of whether variations in the volume of alveoli and alveolar ducts forming single units of ventilation can significantly influence the distribution and uptake of inspired reactive gases. Quantitative serial section analyses of vascular perfusion-fixed rat lungs were used to determine the anatomic dead space proximal to specific ventilatory units as well as the gas volume of these ventilatory units. Three reconstructions, each consisting of ventilatory units distal to a specific bronchus, were carried out. The number of ventilatory units for each reconstruction varied from 26 to 71. The average ventilatory unit volume for the three reconstructions [0.53 +/- .03 (SE) mm3] was not significantly different from measurements based on random sampling. The distribution of ventilatory unit volume was diverse, with 15% of the population having a volume less than 0.3 mm3 and 9% of the population having a volume greater than 1.0 mm3. For a gas of relatively low reactivity (e.g., oxygen) the predicted oxygen uptake per unit surface area did not vary significantly between ventilatory units. The predicted oxygen uptake was approximately 92% of the uptake in the absence of gradients in oxygen concentration between ventilatory units. For a highly reactive gas (e.g., ozone), the predicted uptake per unit surface area in the proximal portions of larger ventilatory units was significantly greater than the average uptake. These results suggest that focal areas of injury likely result from exposure to inhaled reactive gases.

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