scholarly journals Physical and Chemical Properties of Volcanic Ejecta Produced by the Eruption of Mt. Kirishima Shinmoe-dake, Japan -A Case Study After the Explosive Eruption on March 25, 2018-

2021 ◽  
Author(s):  
Hiromi Akita
Keyword(s):  
Particle Size ◽  
Explosive Eruption ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Infiltration Capacity ◽  
Volcanic Ejecta ◽  
Set Up ◽  
Physical And Chemical ◽  
Cylindrical Frame ◽  
And Chemical Properties

Abstract The purpose of this study was to clarify the physical and chemical properties of volcanic ejecta that fell after the explosive eruption on March 25, 2018 at Shinmoe-dake. In order to investigate the infiltration capacity, which is one of the physical properties of volcanic ejecta, plots were set up on the outer forest plain, the forest plain, and the forest talus, and a cylindrical frame test was conducted with reference to the method of Takeshita (2011). In addition, soil samples were collected at the three locations where the cylindrical frame test was conducted. The final infiltration capacity of 38-92 mm / h appeared lower in the forest talus than in the forest plain. It is considered that this is due to the small particle size distribution of 0.1 mm or more, regardless of the particle size of the silt / clay particle size classification. When the chemical properties of the collected volcanic ejecta were examined, Ca and SO4 were contained at high values. Since these compounds become the source of gypsum that reduces infiltration capacity when they react with water, it has become clear that they have the potential to contribute to the generation of debris-flow as a chemical property.

The nature of the sulphur-oxygen bond

1950 ◽  
Vol 200 (1062) ◽  
pp. 409-428 ◽  
Keyword(s):  
Molecular Orbital ◽  
Electronic Structures ◽  
Chemical Properties ◽  
Orbital Method ◽  
Physical And Chemical Properties ◽  
Bond Strengths ◽  
Set Up ◽  
Physical And Chemical ◽  
Oxygen Bond ◽  
And Chemical Properties

The electronic structures of certain molecules containing oxy-sulphur bonds are analyzed insome detail by means of the molecular orbital method. I t is possible to make rough calculations which, despite the complexity of the system s considered, are nevertheless reasonably reliable. The physical and chemical properties of sulphur dioxide, sulphur trioxide and molecules of the types R 2 SO 2 and R 2 SO are discussed on the basis of these structures. In all these molecules it appears that the oxy-sulphur linkages are best described as double-bonded. A successful correlation between the molecular orbital criterion of bond strengths, namely, the bond orders, and the oxy-sulphur bond force constants may be set up. The measure of agreement attained between observed and predicted properties is quite satisfactory.

Control of soil development on the Tanana River floodplain, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 941-955 ◽  
Author(s):  
K. Van Cleve ◽  
C.T. Dyrness ◽  
G.M. Marion ◽  
R. Erickson
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Surface Soil ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Vegetation Development ◽  
River Floodplain ◽  
Soil Particle Size ◽  
Physical And Chemical ◽  
And Chemical Properties

Alluvial soils on the Tanana River floodplain near Fairbanks, Alaska, were examined for development of physical and chemical properties in relation to soil depth and across a 200-year vegetation development sequence. Development was mediated by ecosystem controls including successional time, vegetation, terrace height, soil physical and chemical properties, and microclimate. These controls interact and are conditioned by the state factors time, flora, topography, parent material, and climate, respectively. On early-successional (<5 years) lower alluvial surfaces, terrace height above groundwater, soil particle size, and microclimate (through soil surface evaporation) interacted through capillary rise to produce salt-affected surface soil. Calcium salts of carbonate and sulfate were the principal chemicals encountered in these soils. Establishment of a vegetation cover between 5 and 10 years introduced evapotranspiration as a new mechanism, along with capillarity, to control moisture suction gradients. In addition, newly formed surface litter layers further helped eliminate evaporation and formation of high salt content surface soil. Continued sedimentation raised terrace elevation, so on older terraces only infrequent flood events influenced soil development. Moreover, in these successional stages, only the highest river stages raised groundwater levels, so transpiration and capillarity influenced water movement to tree root systems. During the first 25–30 years of succession, plant deposition of organic matter and nitrogen, associated with the growth of alder, markedly changed soil properties. Nearly 60% (or 240 g•m−2) of the 400 g•m−2 nitrogen encountered at 100 years was accumulated during this early period. After 100 years of vegetation development, soil carbonate content dropped to about half the peak values of about 1600 g•m−2 encountered between 4 and 25 years. By the time white spruce was the dominant forest type at 180 years, carbonate carbon declined to about 500 g•m−2, one-third that of the 1600 g•m−2 high. By this time surface soil pH declined from high values of 7.5 to between 5.5 and 6.0. Organic carbon continued to accumulate to about 6300 g•m−2 in the white spruce stage, twice that encountered in the alder–poplar stage at 25 years. Indices of moisture retention were most strongly related to either soil particle size (low moisture tension and available moisture range) or vegetation-mediated soil organic matter content (high moisture tension). Cation exchange capacity was most strongly related to a vegetation-mediated index of organic matter (OM) content (%N, %C, or %OM).

Influence of Physical and Chemical Properties on the Activity of Fly Ashes

1987 ◽  
Vol 113 ◽  
Author(s):  
F. Sybertz
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Hydrochloric Acid ◽  
Potassium Hydroxide ◽  
Chemical Properties ◽  
Experimental Program ◽  
Physical And Chemical Properties ◽  
Fly Ashes ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTIn an experimental program, the suitability of various methods for testing the pozzolanic activity of fly ash was investigated. The research was conducted on virtually all fly ashes approved as concrete additives in Germany. This paper discusses differences in the particle size distribution and the solubility on dissolution with hydrochloric acid and potassium hydroxide of the fly ashes. It also reports on interrelationships between the physical and chemical properties of the fly ashes and the workability and strength of mortars containing fly ash.

The Impact of Different Grazing Intensity on Topsoil Physical and Chemical Properties in Xilamuren Grassland

2013 ◽  
Vol 295-298 ◽  
pp. 2090-2096
Author(s):  
Yi Fang ◽  
Xiao Jia Li ◽  
Cong Cong Chen ◽  
Min Zhang ◽  
Rui Ping Zhou ◽  
...  
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Chemical Properties ◽  
Grazing Intensity ◽  
Physical And Chemical Properties ◽  
Grassland Ecosystem ◽  
The Difference ◽  
Physical And Chemical ◽  
And Chemical Properties

Grassland is an important ecosystem in land surface. Soil is the basis of grassland ecosystem, and the changes of its properties directly affect grassland ecosystem. The study region is located in Xilamuren grassland using the methods of field sampling and experimental analysis. It was divided into four test areas according to grazing intensity. Soil physical and chemical properties were analyzed in each test area. The results showed that: the trend of soil water content decreased and then increased with increasing grazing intensity, soil water content in repaired grassland was the lowest. For the soil mechanical composition, particle size content increased first and then decreased with increasing grazing intensity when the particle size was 1-0.05mm. The difference between the highest and lowest values was obvious. When the particle size was 0.05-0.002mm, the trend of particle size fluctuated, first decreased and then increased, finally reduce again and the difference between the highest and lowest values was obvious. When the particle size was less than 0.002mm, the trend of particle size content increased with increasing grazing intensity. In soil chemical properties, soil organic matter appears downward trend overall as grazing intensity increase. Soil organic matter content was the lowest in repaired grass. Available N and P first decreased and then increased with increasing grazing intensity, the minimum values appeared in the repaired grassland and degraded grassland respectively. Available K content increased with increasing grazing intensity.

Not All That's Gold Does Glitter

MRS Bulletin ◽  
2001 ◽  
Vol 26 (12) ◽  
pp. 1009-1014 ◽  
Author(s):  
Paul Mulvaney
Keyword(s):  
Particle Size ◽  
Melting Point ◽  
Material Properties ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Gold Particles ◽  
Gold Reserve ◽  
Physical And Chemical ◽  
Gold Metal ◽  
And Chemical Properties

Generally, when one looks up the properties of an element such as gold in an encyclopedia, one is immediately confronted with a list of established facts and figures. While many people are aware that most countries do not rely on a “gold reserve” anymore, it is surprising to learn that even basic physical and chemical properties of something as familiar as gold are not as fixed as one may believe. The reason for this is that tabulated values for material properties inevitably refer to macroscopic samples. It turns out that many simple properties such as those listed in the definition given here go spectacularly wrong as the size of the piece of gold is reduced. One of the most dramatic demonstrations of this was provided by Buffat and Borel, who measured the melting point of gold particles as a function of particle size using an electron microscope. They found that by the time gold crystals are just 4 nm across, the melting point drops to 700 K from its “encyclopedia value” of 1337 K. Another example is the noble character of gold metal.

scholarly journals Industrial Mineral Aggregate Amendment Affects Physical and Chemical Properties of Pine Bark Substrates

HortScience ◽  
2007 ◽  
Vol 42 (5) ◽  
pp. 1287-1294 ◽  
Author(s):  
James S. Owen ◽  
Stuart L. Warren ◽  
Ted E. Bilderback ◽  
Joseph P. Albano
Keyword(s):  
Particle Size ◽  
Chemical Properties ◽  
Pine Bark ◽  
Physical And Chemical Properties ◽  
Water Application ◽  
Volatile Material ◽  
Mineral Aggregate ◽  
Industrial Mineral ◽  
Physical And Chemical ◽  
And Chemical Properties

Nonpoint source effluent containing nitrate N (NO3-N) and phosphorus (P) from containerized nursery production has garnered local, regional, and national concern. Industrial minerals have long been used as absorbents, agrochemical carriers, and barriers to retain heavy metals. Our objective was to determine the effects of a palygorskite–bentonite industrial mineral aggregate on the physical and chemical properties of a soilless substrate and the resulting impact on water and nutrient efficiency. The mineral aggregate had two particle size ranges (0.25 to 0.85 mm or 0.85 to 4.75 mm) in combination with two temperature pretreatments [low volatile material (LVM) or regular volatile material (RVM)]. A representative substrate (8 pine bark:1 coarse sand) of the southeastern United States nursery industry was also included in the study as a control. Cotoneaster dammeri C.K. Schneid. ‘Skogholm’ was grown in all substrates on collection pads that allowed for the quantification of daily influent and effluent volumes to calculate cumulative NO3-N, ammonium N (NH4-N), and dissolved reactive phosphorus (DRP) loss for 112 days. There was a 13% to 15% decrease in daily water application volume with no effect on Skogholm cotoneaster growth, which equated into a savings of 22 to 26 L per 14-L container in mineral aggregate-amended substrates compared with a sand-amended substrate (control). Mineral aggregate-amended substrates decreased NH4-N and DRP effluent 39% and 34%, respectively, compared with the control. In addition, LVM and particle size 0.25 to 0.85 mm reduced effluent DRP compared with the 0.85 to 4.75-mm RVM aggregate. Plant dry weight was unaffected by any of the treatments. Substantial nutrient content reduction in effluent and reductions in water application were achieved with amending pine bark with 0.25 to 0.85 mm LVM industrial mineral aggregate. A 0.25 to 0.85-mm LVM industrial mineral aggregate pine bark-amended substrate reduced effluent DRP and NH4-N greater than 40% and reduced water application 15% or 26 L when compared with the industry representative substrate.

scholarly journals IMPACT OF EROSION PROCESS TO FERTILITY OFMOUNTAIN-CHERNOZEM SITUATING IN SOUTH-EAST SLOPE OF GREAT CAUCASIAN

2018 ◽  
Vol 5 ◽  
pp. 389-394
Author(s):  
Soltanzade Gasim Ali oglu
Keyword(s):  
Preventive Measures ◽  
Chemical Properties ◽  
Anthropogenic Factors ◽  
Sharp Change ◽  
Physical And Chemical Properties ◽  
Erosion Process ◽  
Set Up ◽  
Physical And Chemical ◽  
The Village ◽  
And Chemical Properties

The complexity, sharp change in the relief condition, the tension of the anthropogenic factors in the Shamakhi region, where we have investigated, has intensified the erosion process. Because of the lack of agrotechnical measures on the slopes, the erosion process has been intensified, the soil is flooded with soil, the physical and chemical properties of the soil have deteriorated, the nutritional elements have declined, the vegetation has been degraded and reached the limit of destruction. For some reason, the object of research was Shamakhi two land cuts were set up to determine the degree of actual erosion of the soil in the village of Melam. which will result in preventive measures to prevent erosion intensities and to develop and implement appropriate preventive measures

Nanocontainers for drug delivery systems: A review of Halloysite nanotubes and their properties

2020 ◽  
pp. 039139882096883
Author(s):  
Melika Hasani ◽  
Majid Abdouss ◽  
Shahrokh Shojaei
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Delivery Systems ◽  
Chemical Properties ◽  
Drug Carriers ◽  
Halloysite Nanotubes ◽  
Environmentally Benign ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Halloysite nanotubes (HNTs) are known as inexpensive and available nanomaterials that are rich in functionality, environmentally benign, and also safe and easy to process. As well, good particle size (i.e. nanoscale) and perfect tubular microstructures of these materials make them to be used extensively as drug carriers. Also, the unique physical and chemical properties of their internal and external surfaces are the greatest priority for the drug encapsulation controlling and releasing. In this review, is tried to emphasis on the main properties of HNTs to manage and develop effective drug delivery tools in the biomedical and pharmaceutical fields.

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