SOUND SPEED AND RELATED PHYSICAL PROPERTIES OF SEDIMENTS FROM EXPERIMENTAL MOHOLE (GUADALUPE SITE)

Geophysics ◽  
1965 ◽  
Vol 30 (2) ◽  
pp. 257-261 ◽  
Author(s):  
Edwin L. Hamilton
Keyword(s):  
Physical Properties ◽  
Sound Speed ◽  
Sediment Surface ◽  
Laboratory Measurements ◽  
Small Reduction ◽  
Surficial Sediments ◽  
Sediment Samples ◽  
Sea Floor ◽  
Interval Velocity

Sediment samples from the Guadalupe Site Mohole drilling program of 1961 have been tested for sound speed and related physical properties. Laboratory measurements of sound speed have been corrected to in‐situ values by making corrections for the temperature gradient within the sediment body, for hydrostatic water pressures within sediment pore spaces, and for a small reduction in porosity. Resulting in‐situ sound speeds vary from 1,484 m/sec at the sediment surface to 1,584 m/sec at a depth in the sediment of 136 m. The resulting sound‐velocity gradient is approximately [Formula: see text]; the interval velocity is about 1,565 m/sec. Sound speed in the surficial sediments is about 2.2 percent less than in the water just above the sea floor.

scholarly journals Modelling of speleothems failure in the Hotton cave (Belgium). Is the failure earthquake induced?

2001 ◽  
Vol 80 (3-4) ◽  
pp. 315-321 ◽  
Author(s):  
J.F. Cadorin ◽  
D. Jongmans ◽  
A. Plumier ◽  
T. Camelbeeck ◽  
S. Delaby ◽  
...  
Keyword(s):  
Natural Frequencies ◽  
Quantitative Information ◽  
Rigid Bodies ◽  
Tensile Failure ◽  
Future Research ◽  
Geometrical Parameters ◽  
Laboratory Measurements ◽  
Ground Acceleration ◽  
Strong Ground

AbstractTo provide quantitative information on the ground acceleration necessary to break speleothems, laboratory measurements on samples of stalagmite have been performed to study their failure in bending. Due to their high natural frequencies, speleothems can be considered as rigid bodies to seismic strong ground motion. Using this simple hypothesis and the determined mechanical properties (a minimum value of 0.4 MPa for the tensile failure stress has been considered), modelling indicates that horizontal acceleration ranging from 0.3 m/s2 to 100 m/s2 (0.03 to 10g) are necessary to break 35 broken speleothems of the Hotton cave for which the geometrical parameters have been determined. Thus, at the present time, a strong discrepancy exists between the peak accelerations observed during earthquakes and most of the calculated values necessary to break speleothems. One of the future research efforts will be to understand the reasons of the defined behaviour. It appears fundamental to perform measurements on in situ speleothems.

scholarly journals Microstructural Characteristics of Frazil Particles and the Physical Properties of Frazil Ice in the Yellow River, China

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 617
Author(s):  
Yaodan Zhang ◽  
Zhijun Li ◽  
Yuanren Xiu ◽  
Chunjiang Li ◽  
Baosen Zhang ◽  
...  
Keyword(s):  
Physical Properties ◽  
Yellow River ◽  
The Yellow River ◽  
Ice Crystal ◽  
Microstructural Characteristics ◽  
Air Bubble ◽  
Frazil Ice ◽  
Sediment Content ◽  
Crystal Diameter

Frazil particles, ice crystals or slushy granules that form in turbulent water, change the freezing properties of ice to create “frazil ice”. To understand the microstructural characteristics of these particles and the physical properties of frazil ice in greater depth, an in situ sampler was designed to collect frazil particles in the Yellow River. The ice crystal microstructural characteristics of the frazil particles (morphology, size, air bubble, and sediment) were observed under a microscope, and their nucleation mechanism was analyzed according to its microstructure. The physical properties of frazil ice (ice crystal microstructure, air bubble, ice density, and sediment content) were also observed. The results showed that these microstructures of frazil particles can be divided into four types: granular, dendritic, needle-like, and serrated. The size of the measured frazil particles ranged from 0.1 to 25 mm. Compared with columnar ice, the crystal microstructure of frazil ice is irregular, with a mean crystal diameter less than 5 mm extending in all directions. The crystal grain size and ice density of frazil ice are smaller than columnar ice, but the bubble and sediment content are larger.

In situ polymerized poly(butylene succinate)/silica nanocomposites: Physical properties and biodegradation

2008 ◽  
Vol 93 (5) ◽  
pp. 889-895 ◽  
Author(s):  
Sang-Il Han ◽  
Jung Seop Lim ◽  
Dong Kook Kim ◽  
Mal Nam Kim ◽  
Seung Soon Im
Keyword(s):  
Physical Properties ◽  
Butylene Succinate ◽  
Silica Nanocomposites

Estimation and Scaling of the Near-Saturated Hydraulic Conductivity

1999 ◽  
Vol 30 (3) ◽  
pp. 177-190 ◽  
Author(s):  
Per Atle Olsen
Keyword(s):  
Hydraulic Conductivity ◽  
Saturated Hydraulic Conductivity ◽  
Scaling Analysis ◽  
Laboratory Measurements ◽  
Estimation Errors ◽  
Geometric Means ◽  
Top Soil ◽  
Structured Soils ◽  
Order Of Magnitude

The hydraulic conductivity in structured soils is known to increase drastically when approaching saturation. Tension infiltration allows in situ infiltration of water at predetermined matric potentials, thus allowing exploration of the hydraulic properties near saturation. In this study, the near saturated (ψ≥-0.15 m) hydraulic conductivity was estimated both in the top- and sub-soil of three Norwegian soils. A priory analysis of estimation errors due to measurement uncertainties was conducted. In order to facilitate the comparison between soils and depths, scaling analysis was applied. It was found that the increase in hydraulic conductivity with increasing matric potentials (increasing water content) was steeper in the sub-soil than in the top-soil. The estimated field saturated hydraulic conductivity was compared with laboratory measurements of the saturated hydraulic conductivity. The geometric means of the laboratory measurements was in the same order of magnitude as the field estimates. The variability of the field estimates of the hydraulic conductivity from one of the soils was also assessed. The variability of the field estimates was generally smaller than the laboratory measurements of the saturated hydraulic conductivity.

scholarly journals Flow-law hypotheses for ice-sheet modeling

1992 ◽  
Vol 38 (129) ◽  
pp. 245-256 ◽  
Author(s):  
Richard B. Alley
Keyword(s):  
Physical Properties ◽  
Ice Sheets ◽  
Diffusion Control ◽  
Ice Streams ◽  
Ice Shelves ◽  
Dislocation Glide ◽  
Ice Sheet Modeling ◽  
Flow Law ◽  
Power Law Creep

AbstractIce-flow modeling requires a flow law relating strain rates to stresses in situ, but a flow law cannot be measured directly in ice sheets. Microscopic processes such as dislocation glide and boundary diffusion control both the flow law for ice and the development of physical properties such as grain-size andc-axis fabric. These microscopic processes can be inferred from observations of the physical properties, and the flow law can then be estimated from the microscopic processes.A review of available literature shows that this approach can be imperfectly successful. Interior regions of large ice sheets probably have depth-varying flow-law “constants”, with the stress exponent,n, for power-law creep less than 3 in upper regions and equal to 3 only in deep ice;nprobably equals 3 through most of the thickness of ice shelves and ice streams.

scholarly journals Influence of expanded graphite (EG) and graphene oxide (GO) on physical properties of PET based nanocomposites

2014 ◽  
Vol 16 (4) ◽  
pp. 45-50 ◽  
Author(s):  
Sandra Paszkiewicz ◽  
Małgorzata Nachman ◽  
Anna Szymczyk ◽  
Zdeno Špitalský ◽  
Jaroslav Mosnáček ◽  
...  
Keyword(s):  
Physical Properties ◽  
In Situ Polymerization ◽  
Crystallization Rate ◽  
Expanded Graphite ◽  
Exfoliated Graphene ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Agglomeration Of Nanoparticles ◽  
Graphite Sheets

Abstract This work is the continuation and refinement of already published communications based on PET/EG nanocomposites prepared by in situ polymerization1, 2. In this study, nanocomposites based on poly(ethylene terephthalate) with expanded graphite were compared to those with functionalized graphite sheets (GO). The results suggest that the degree of dispersion of nanoparticles in the PET matrix has important effect on the structure and physical properties of the nanocomposites. The existence of graphene sheets nanoparticles enhances the crystallization rate of PET. It has been confirmed that in situ polymerization is the effective method for preparation nanocomposites which can avoid the agglomeration of nanoparticles in polymer matrices and improve the interfacial interaction between nanofiller and polymer matrix. The obtained results have shown also that due to the presence of functional groups on GO surface the interactions with PET matrix can be stronger than in the case of exfoliated graphene (EG) and matrix.

scholarly journals Becoming symbiotic – the symbiont acquisition and the early development of bathymodiolin mussels

2020 ◽  
Author(s):  
Maximilian Franke ◽  
Benedikt Geier ◽  
Jörg U. Hammel ◽  
Nicole Dubilier ◽  
Nikolaus Leisch
Keyword(s):  
Early Development ◽  
Light And Electron Microscopy ◽  
Deep Ocean ◽  
Life Stages ◽  
Sea Floor ◽  
Symbiotic Associations ◽  
Nutritional Strategy ◽  
Early Developmental ◽  
Symbiont Acquisition

AbstractSymbiotic associations between animals and microorganisms are widespread and have a profound impact on the ecology, behaviour, physiology, and evolution of the host. Research on deep-sea mussels of the genus Bathymodiolus has revealed how chemosynthetic symbionts sustain their host with energy, allowing them to survive in the nutrient-poor environment of the deep ocean. However, to date, we know little about the initial symbiont colonization and how this is integrated into the early development of these mussels. Here we analysed the early developmental life stages of B. azoricus, “B”. childressi and B. puteoserpentis and the changes that occur once the mussels are colonized by symbionts. We combined synchrotron-radiation based μCT, correlative light and electron microscopy and fluorescence in situ hybridization to show that the symbiont colonization started when the animal settled on the sea floor and began its metamorphosis into an adult animal. Furthermore, we observed aposymbiotic life stages with a fully developed digestive system which was streamlined after symbiont acquisition. This suggests that bathymodiolin mussels change their nutritional strategy from initial filter-feeding to relying on the energy provided by their symbionts. After ~35 years of research on bathymodiolin mussels, we are beginning to answer fundamental ecological questions concerning their life cycle and the establishment of symbiosis.

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