The comparative effects of exchangeable calcium, magnesium, and sodium on some physical properties of red-brown earth subsoils. II. The spontaneous dispersion of aggregates in water

Soil Research ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 151 ◽  
Author(s):  
WW Emerson ◽  
AC Bakker
Keyword(s):  
Physical Properties ◽  
Water Uptake ◽  
Salt Concentration ◽  
The Other ◽  
Soluble Salt ◽  
Chloride Solutions ◽  
Actual Concentration ◽  
Exchangeable Calcium ◽  
Calcium Magnesium ◽  
Natural Aggregates

Aggregates from the subsoils of four red-brown earths were brought into equilibrium with chloride solutions of known SAR, 1 mM in calcium or magnesium. The solutions were replaced by water and the amount of clay which subsequently dispersed from the aggregates measured. For the three soils from the same area, the ESP required to induce dispersion was about 3 for magnesium-sodium aggregates compared with 5 for calcium-sodium aggregates. For the other soil the respective ESP values had to be increased by a factor of 2. The increased resistance to dispersion of the latter was maintained even after sodium saturation. The results are used to show that differences in the dispersion of the natural aggregates in water are due primarily to the composition of the cations on the exchange sites, including aluminium. Shepparton aggregates of known ESP were wetted with water at 12 cm suction. Compared with calcium or magnesium aggregates, there was a marked further water uptake by magnesium-sodium aggregates for ESP > 3 and for calcium-sodium aggregates for ESP >9. The subsequent dispersion in water of such aggregates was much less than that of aggregates treated in the standard way. It is suggested that the spontaneous dispersion of clay from a wet aggregate of low ESP immersed in water depends on the gradient of the soluble salt concentration at the boundary of the intact portion of the aggregate, as well as the actual concentration.

Exchangeable calcium, magnesium and sodium and the dispersion of illites in water. II. Dispersion of illites in water

Soil Research ◽  
1977 ◽  
Vol 15 (3) ◽  
pp. 255 ◽  
Author(s):  
WW Emerson ◽  
CL Chi
Keyword(s):  
Water Content ◽  
Particle Aggregation ◽  
The Other ◽  
Clay Particles ◽  
Exchangeable Calcium ◽  
Soil Clays ◽  
Exchangeable Magnesium ◽  
Calcium Magnesium ◽  
Calcium And Magnesium ◽  
Dominant Cation

Samples of illites, two extracted from soils, one from a shale, prepared with a range of exchangeable calcium, magnesium, sodium were immersed dry into water. The extent of dispersion with time was estimated visually and also deduced from the O.D. of the suspensions derived from the dispersed clay. The dispersion of wet calcium and magnesium soil illites sheared at a given water content and then immersed in water was also assessed visually. The dispersion of all three illites was enhanced when magnesium was the dominant cation rather than calcium. For the soil clays a lower ESP was required to initiate dispersion of the dry clay when immersed in water. Both calcium and magnesium forms of the shale illite dispersed partially over a period of several days when immersed dry into water, the magnesium to a greater extent than calcium. The magnesium form of the coarser of the two soil illites also dispersed slowly. By comparing the calcium-magnesium and calcium-sodium forms of the last clay, it was deduced that about 10 times the equivalent concentration of exchangeable magnesium as sodium was needed to cause the same degree of dispersion. For the other soil illite the water content for dispersion of the wet, sheared magnesium clay was found to be less than for the calcium clay. The O.D. of suspensions of the clays was found to decrease with increasing ESP and when magnesium was the dominant cation rather than calcium. This is explained in terms of particle aggregation. The ease of dispersion of the illites was correlated with particle size. Possible reasons for this, and the effect of magnesium, as opposed to calcium, on the forces between the clay particles are discussed.

Primary and conditional basic exchangeable cations in Australian soil profiles

Soil Research ◽  
1975 ◽  
Vol 13 (1) ◽  
pp. 91
Author(s):  
BM Tucker
Keyword(s):  
Exchangeable Cations ◽  
The Other ◽  
Soil Profiles ◽  
Exchange Reactions ◽  
Exchangeable Calcium ◽  
Calcium Magnesium ◽  
Australian Soil

The examination of a range of soil profiles showed that both primary and conditional exchangeable calcium, magnesium and sodium are present in all the soils, but the proportions of these subsets vary widely. There are some general correlations with profile form, and it is likely that the partition of these exchangeable cations will prove useful in studying the properties and behaviour of soils. Potassium differs from the other three cations in its exchange reactions-it is present almost entirely in the conditional subset-and it requires an additional exchange reagent to partition it successfully.

The comparative effects of exchangeable calcium, magnesium, and sodium on some physical properties of red-brown earth subsoils. I. Exchange reactions and water contents for dispersion of Shepparton soil

Soil Research ◽  
1973 ◽  
Vol 11 (2) ◽  
pp. 143 ◽  
Author(s):  
AC Bakker ◽  
WW Emerson ◽  
JM Oades
Keyword(s):  
Physical Properties ◽  
Water Content ◽  
Ammonium Chloride ◽  
Clay Fraction ◽  
Exchange Reactions ◽  
Exchangeable Calcium ◽  
Soil Calcium ◽  
Calcium Magnesium ◽  
Calcium And Magnesium ◽  
Water Contents

The susceptibility to waterlogging of red-brown earth subsoils is discussed. One of these, Shepparton, has been leached with chloride solutions of given SAR, in the range 0-7, the last solution being 1 mM in calcium or magnesium. The soil was then extracted with neutral lM ammonium chloride and the displaced cations measured. The exchange of sodium for both calcium and magnesium was similar, following the Gapon equation except at very low SAR values. Some potassium and sodium was extracted from calcium and magnesium soils. Shepparton soil of known SAR was remoulded over a range of water contents and synthetic aggregates formed. The percentage of the clay fraction which dispersed from the aggregates was measured. The water content for perceptible dispersion of magnesium soil was only about half that of calcium soil, the water contents being near the 15 bar and 0.1 bar values respectively for unsheared soil. The water content for dispersion decreased sharply with increasing SAR of the soil. Calcium-sodium soil with an ESP of 3.5 dispersed at the same water content as magnesium soil. Possible reasons for the enhanced dispersion of sheared, wet magnesium soil compared with similar calcium soil are discussed.

HAYNES STELLITE ALLOY No. 98M2

Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Physical Properties ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
The Other ◽  
Stellite Alloy ◽  
Cobalt Base Alloy ◽  
Cobalt Base

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.

scholarly journals IX. The electric conductivity of nitric acid

1898 ◽  
Vol 191 ◽  
pp. 365-398 ◽  
Keyword(s):  
Nitric Acid ◽  
Physical Properties ◽  
Nitrous Acid ◽  
Internal Resistance ◽  
The Other ◽  
Reasonable Degree ◽  
Mineral Acids ◽  
Artificial Illumination ◽  
The Subject ◽  
Deep Green

Of the commoner mineral acids the chemical changes of Nitric Acid, from their evident complexity, have formed the subject of numerous memoirs, while those of sulphuric acid, from their assumed simplicity, have been to some degree neglected; on the other hand, the physical properties of the latter have been studied with considerable elaboration, while those of the former have been passed over, doubtless on account of the corrosive nature of the acid and the difficulty of preparing and preserving it in a reasonable degree of purity. Further, with certain exceptions, the alterations in physical properties induced by the products of reduction, be they nitrogen peroxide or nitrous acid, either singly or conjointly, have attracted but little attention, though it is a common matter of observation that the current intensity of a Grove’s or other cell containing nitric acid remains constant, even though the fuming acid, originally colourless or red, has become of a deep green tint. It is more than probable that of the factors of Ohm’s law, both the E. M. F. and internal resistance are continually varying. At the earliest stages of the enquiry it was found that the passage of a few bubbles of nitric oxide gas into a considerable volume of nitric acid produced an alteration of one percent, in the resistance, and the same result could be effected to a less degree by exposure to sunlight, and to a still less degree by exposure to artificial illumination. Therefore, we determined to investigate the alterations of conductivity produced by changes of concentration and temperature in samples of acid purified with necessary precautions, more especially as former workers upon the subject have either used samples of acid confessedly impure, or have been silent as to any method of purification, or have adopted no special care in dealing with a substance so susceptible of polarisation.

scholarly journals Some Preliminary Notes on the Physical Properties of the Soils of the Ganges Valley, more especially in their relation to Soil Moisture

1906 ◽  
Vol 1 (4) ◽  
pp. 454-469 ◽  
Author(s):  
H. M. Leake
Keyword(s):  
Soil Moisture ◽  
Physical Properties ◽  
Short Duration ◽  
Irrigation Water ◽  
The Other ◽  
Indian Agriculture ◽  
Northern India ◽  
The One ◽  
The Ganges

In a stretch of arable lands like those of the Ganges Valley, although damage may be caused by occasional floods, which are sudden and of short duration, the more general, and by far the most serious loss is due to deficiency of moisture of the soil: thus the relation of the soil to soil moisture becomes of more than ordinary importance. Dr Voelcker, in his Report on Indian Agriculture, remarks: “In India the relation of soils to moisture acquires a greater significance than almost anywhere else.......” This relation is fundamental, for on it depends the methods for the conservation of soil moisture, for the economical application of irrigation water, and for the treatment of barren and salt lands—all problems of direct interest to agriculturists in the plains of Northern India. The methods for dealing with these problems must be largely—if not entirely—empirical until such time as the behaviour of the soil in its relation to moisture is investigated. The problem in all its various branches is enormous, and in a country in which the seasons follow each other with such rapidity, and vary the one from the other in so marked a manner, it frequently happens that a particular point, if not determined within a period of a few days, must await solution until the following year.

Water Uptake and Embryonic Development in Eggs of Chorthippus Brunneus Thunberg (Saltatoria: Acrididae)

1969 ◽  
Vol 50 (2) ◽  
pp. 327-333
Author(s):  
F. MORIARTY
Keyword(s):  
Sodium Chloride ◽  
Embryonic Development ◽  
Water Absorption ◽  
Osmotic Pressure ◽  
Water Uptake ◽  
Water Loss ◽  
Chloride Solutions ◽  
Sodium Chloride Solutions ◽  
Close Relationship ◽  
Further Development

1. The pattern of water absorption by eggs of Chorthippus brunneus varies greatly between individuals. 2. The time at which water is absorbed does not have a close relationship with the stage of embryonic development. 3. Water absorption is not essential for prediapause development. 4. Eggs can only undergo blastokinesis and further development, after diapause is broken, if some water has been absorbed. 5. The rate of water loss or gain varies with the osmotic pressure of sodium chloride solutions. 6. Eggs which have started to absorb water appear to become desiccated more rapidly than eggs which have not.

scholarly journals Relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture

2009 ◽  
Vol 44 (8) ◽  
pp. 996-1001 ◽  
Author(s):  
Pedro Rodolfo Siqueira Vendrame ◽  
Robélio Leandro Marchão ◽  
Osmar Rodrigues Brito ◽  
Maria de Fátima Guimarães ◽  
Thierry Becquer
Keyword(s):  
Total Carbon ◽  
Soil Macrofauna ◽  
Exchangeable Calcium ◽  
Exchangeable Ca ◽  
Calcium Magnesium ◽  
Distrito Federal ◽  
Calcium And Magnesium ◽  
Taxonomic Groups ◽  
The Relationship ◽  
Soil Groups

The objective of this work was to assess the relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture. Twelve collection points were chosen in the Distrito Federal and in Formosa municipality, Goiás state, Brazil, representing four soil groups with varied levels of calcium + magnesium and kaolinite/(kaolinite + gibbsite) ratios. Soil macrofauna was collected in triplicate at each collection point, and identified at the level of taxonomic groups. Macrofauna density showed correlation with contents of kaolinite, gibbsite and exchangeable Ca + Mg in the soils. Mineralogy and exchangeable Ca + Mg had significant effects on taxonomic groups and relative density of soil macrofauna. The termites (Isoptera) were more abundant in soils with low exchangeable Ca + Mg; earthworms (Oligochaeta), in soils with high levels of kaolinite; and Hemiptera and Coleoptera larvae were more abundant in gibbsitic soils with higher contents of total carbon.

scholarly journals Effect of soaking process on physical properties of mature pepper berries (Piper nigrum L.)

Food Research ◽  
2020 ◽  
Vol 4 (S1) ◽  
pp. 116-123
Author(s):  
A.A.P.N. Megat ◽  
Rosnah Shamsudin ◽  
H. Che Man ◽  
M.E. Ya'acob
Keyword(s):  
Physical Properties ◽  
Water Uptake ◽  
Major Axis ◽  
Minor Axis ◽  
Piper Nigrum ◽  
Uptake Ratio ◽  
Fracture Force ◽  
Brown Colour

This study was carried out to determine the effect of the soaking process on the physical properties of the mature pepper berries. The soaking process was conducted by immersing pepper berries in water. The results showed the dimensions of the pepper berries before soaking was 5.24 mm (minor axis), 5.57 mm (medium axis) and 5.61 mm (major axis). The weight of pepper berries increased from day 1 (13.58%) until day 3 (16.92%) and decreased after day 4 (0.77%) until day 7 of soaking (13.08%). The water uptake ratio of soaked pepper berries increased from 1.14% (day 1) until 1.17% (day 3) and then decreased from 1.01% (day 4) until 0.87% (day 7). The fracture force required to fracture the pericarp was decreased starting from 67.21 N (day 1) decreased until 21.40 N (day 7). The colour of mature pepper berries was changed into black-brown colour (L= 34.16, a= 1.38, b= 1.40).

Sign in / Sign up

Export Citation Format

Share Document