scholarly journals A Calculation Theory of Earth Pressure Considering Microstructure of Porous Materials

2018 ◽  
Vol 142 ◽  
pp. 02010
Author(s):  
Jun-hu Li ◽  
Chao Zhang ◽  
Wei Xue ◽  
Wen-chao Zhang ◽  
Ri-qing Xu
Keyword(s):  
Contact Area ◽  
Soft Clay ◽  
Stress Transfer ◽  
Earth Pressure ◽  
Transfer Principle ◽  
Lateral Stress ◽  
Microstructure Characteristics ◽  
Pressure Calculation ◽  
The Relationship ◽  
Scanning Electron

To explore a more reasonable earth pressure calculation theory, microstructure characteristics of soft clay in Hangzhou, Ningbo and Wenzhou had been observed using scanning electron microscope (SEM) and were quantitatively analysed using Image-Pro Plus (IPP) software. The relationship between porosity and contact area of soft clay was got by considering the microstructure. Combining soil lateral stress transfer principle, a calculation theory of earth pressure considering soil contact area was got. The possible reason of the differences between earth pressure and the actual monitoring earth pressure was analysis by the case.

The Relationship between Retaining Wall Deformation and Earth Pressure in Deep Excavation

2012 ◽  
Vol 446-449 ◽  
pp. 1690-1695
Author(s):  
She Qin Peng ◽  
Qi Hua Zhao ◽  
Zi Yang Chen
Keyword(s):  
Retaining Wall ◽  
Earth Pressure ◽  
Suspension Bridge ◽  
Deep Excavation ◽  
Foundation Pit ◽  
Retaining Structure ◽  
Pressure Calculation ◽  
Wall Deformation ◽  
Pit Depth ◽  
The Relationship

Earth pressure may change with retaining wall deformation in the process of deep excavating. But how? The answer can be very important to the safety of retaining system. Using monitoring data of north anchor foundation pit of Runyang suspension bridge, this paper studied retaining structure and soil interaction. Find the relationship between retaining wall deformation and earth pressure in deep excavation. In this case, earth pressure increased with wall deformation upward the depth of 18m and decreased with wall deformation down below. A regression equation about foundation pit depth and ratio of earth pressure and wall deformation was established. Then give a simplified earth pressure calculation method considering retaining wall deformation.

Dispersion technology on mechanical properties of carbon nanomaterials reinforced epoxy nanocomposites

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040019
Author(s):  
Chin-Lung Chiang ◽  
Chien-Wei Hsu ◽  
Hsiu-Ming Wu ◽  
Ming-Yuan Shen
Keyword(s):  
Mechanical Properties ◽  
Contact Area ◽  
Carbon Nanomaterials ◽  
Flexural Modulus ◽  
Stress Transfer ◽  
Phonon Transport ◽  
Epoxy Nanocomposites ◽  
Constant Area ◽  
Surface Contact Area ◽  
Scanning Electron

Graphene nanoplatelets (GNPs) are platelet-liked graphite nanocrystals with multigraphene layers. In general, a high contact area between polymer and nanofiller maximizes stress transfer from the polymer matrix to nanofillers. Therefore, GNPs can be expected to exhibit better reinforcement than CNTs in polymer composites, because of their ultrahigh aspect ratio (600–10,000) and higher surface constant area. The GNPs planar structure provides a 2D path for phonon transport, and the ultrahigh surface area allows a large surface contact area with polymer resulting in the enhancement of the composite thermal conductivity. In this study, simple and efficient planetary mixing methods were used to enable the GNPs to disperse uniformly throughout the epoxy solution (i.e. 0, 0.1, 0.25, 0.5, 0.75, and 1.0 wt%) and then to prepare GNPs/epoxy nanocomposites. Mechanical properties of the nanocomposite, including ultimate tensile, flexural strength and flexural modulus, were investigated. Finally, the fracture surface of the specimen was investigated using scanning electron microscopy (SEM) to determine the dispersion of the GNPs in the composites.

Effects of Conditioners on Dewatering Properties of Sludge and its Microstructure Characteristics

2011 ◽  
Vol 239-242 ◽  
pp. 2461-2465
Author(s):  
Ling Zhang ◽  
Yuan Chen ◽  
Chang Bin Xia ◽  
Fan Gao ◽  
Ying Zhu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sludge Dewatering ◽  
Microstructure Characteristics ◽  
Sludge Cake ◽  
The Relationship ◽  
Different Order ◽  
Scanning Electron

In order to study the sludge microstructure and dewatering performance, the sludge was treated using different conditioners, the same conditioner in a different dosage, the same formula in a different proportion and different order of adding conditioners. The microstructure of dehydrated sludge was observed by scanning electron microscopy. The relationship between the sludge dewatering properties and microstructure characteristics was discussed. It was proven that the different dehydration performance correspond to the different morphology. The better dewatering performance shows more pore at the surface of sludge cake.Contractly, the sludge cake with poor dewatering perform a dense surface, even membranous. Therefore, there is a certain of relationship between the microstructure of sludge cake and its dehydration performance.

An Experimental Evaluation of the Constant β Relating the Contact Stiffness to the Contact Area in Nanoindentation

2004 ◽  
Vol 841 ◽  
Author(s):  
Jeremy H. Strader ◽  
Sanghoon Shim ◽  
Hongbin Bei ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Mechanical Properties ◽  
Contact Area ◽  
Contact Stiffness ◽  
Experimental Measurements ◽  
Berkovich Indenter ◽  
Cube Corner ◽  
Fused Quartz ◽  
The Relationship ◽  
Theoretical Analyses ◽  
Scanning Electron

ABSTRACTMeasurements of mechanical properties by nanoindentation with triangular pyramidal indenters like the Berkovich rely heavily upon the relationship between the contact stiffness, S, the contact area, A, and the reduced elastic modulus, Er. This relationship is often written in the form S = 2βEr(A/π)1/2, where β is a constant that depends on the geometry of the indenter. Although the most common values for β used in experimental measurements are 1.000 and 1.034, various theoretical analyses have yielded values as small as 1.00 or as large as 1.2, depending on the assumptions made to model the deformation. Here, we explore the most appropriate value of β by performing careful experiments in fused quartz with thin gold coatings applied to the surface to reveal the actual contact area when observed in the scanning electron microscope. Experiments were performed not only with the Berkovich indenter, but with five other three-sided pyramidal indenters with centerline-to-face angles ranging from 35.3° (cube corner) to 85°. Results are discussed as they apply to obtaining accurate measurements of mechanical properties by nanoindentation.

scholarly journals Three-dimensional relationships between tumor cells and microcirculation with double cyanine immunolabeling, laser scanning confocal microscopy, and computer-assisted reconstruction: an alternative to cast corrosion preparations.

1994 ◽  
Vol 42 (5) ◽  
pp. 681-686 ◽  
Author(s):  
V Rummelt ◽  
L M Gardner ◽  
R Folberg ◽  
S Beck ◽  
B Knosp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Blood Vessels ◽  
Tumor Cells ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Melanoma Cells ◽  
Tumor Blood Vessels ◽  
The Relationship ◽  
Scanning Electron

The morphology of the microcirculation of uveal melanomas is a reliable market of tumor progression. Scanning electron microscopy of cast corrosion preparations can generate three-dimensional views of these vascular patterns, but this technique sacrifices the tumor parenchyma. Formalin-fixed wet tissue sections 100-150 microns thick from uveal melanomas were stained with the lectin Ulex europaeus agglutinin I (UEAI) and proliferating cell nuclear antigen (PCNA) to demonstrate simultaneously the tumor blood vessels and proliferating tumor cells. Indocarbocyanine (Cy3) was used as a fluorophore for UEAI and indodicarbocyanine (Cy5) was used for PCNA. Double labeled sections were examined with a laser scanning confocal microscope. Images of both stains were digitized at the same 5-microns intervals and each of the two images per interval was combined digitally to form one image. These combined images were visualized through voxel processing to study the relationship between melanoma cells expressing PCNA and various microcirculatory patterns. This technique produces images comparable to scanning electron microscopy of cast corrosion preparations while permitting simultaneous localization of melanoma cells expressing PCNA. The microcirculatory tree can be viewed from any perspective and the relationship between tumor cells and the tumor blood vessels can be studied concurrently in three dimensions. This technique is an alternative to cast corrosion preparations.

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE CHARACTERISTICS OF LASER COMPOSITES

2014 ◽  
Vol 21 (01) ◽  
pp. 1450014
Author(s):  
PENG LIU ◽  
YUANBIN ZHANG ◽  
YAJIANG LI ◽  
QINGQING YANG ◽  
YAN LIU ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electron Microscope ◽  
Theoretical Basis ◽  
Laser Alloying ◽  
Wear Properties ◽  
Microstructure Characteristics ◽  
Transmission Electron ◽  
Treatment Technologies ◽  
Intensity Transfer ◽  
Scanning Electron

In this paper, effect of heat treatment on the microstructures and wear properties of laser alloying (LA) composites is investigated. LA of the T - Co 50/ FeSi / TiC / TiN / CeO 2 mixed powders on substrate of 45 steel can form the hard composites, which increased the wear resistance of substrate greatly. Such LA composites were investigated by means of a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The tempering promoted the growth of the block-shape hard phases, favoring an enhancement of the integrity of block-shape hard phases; and tempering also improved greatly the formation mechanism, guarantying the composites to have enough ability of intensity transfer. This research provided essential experiment and theoretical basis to promote the application of the laser and heat treatment technologies in the field of surface modification.

Conditioning of a culture substratum by the ectodermal layer promotes attachment and oriented locomotion by amphibian gastrula mesodermal cells

1983 ◽  
Vol 59 (1) ◽  
pp. 43-60 ◽  
Author(s):  
N. Nakatsuji ◽  
K.E. Johnson
Keyword(s):  
Cell Migration ◽  
Time Lapse ◽  
Ambystoma Maculatum ◽  
Specific Cell ◽  
Animal Pole ◽  
Micron Diameter ◽  
The Relationship ◽  
Extracellular Fibrils ◽  
Scanning Electron

We have found that ectodermal fragments of Ambystoma maculatum gastrulae deposit immense numbers of 0.1 micron diameter extracellular fibrils on plastic coverslips. When migrating mesodermal cells from A. maculatum gastrulae are seeded on such conditioned plastic substrata, they attach and begin migrating after 15–30 min in vitro. We did a detailed analysis of the relationship between fibril orientation and cell migration using time-lapse cinemicrography, scanning electron microscopy, and a microcomputer with a graphics tablet and morphometric program. We found that cells move in directions closely related to the orientation of fibrils. Usually fibrils are oriented in dense arrays with a predominance of fibrils running parallel to the blastopore-animal pole axis of the explant, and cells move preferentially along lines parallel to the blastopore-animal pole axis. When fibrils are unaligned, cells move at random. We have also shown that cells move with a slightly stronger tendency towards the animal pole direction. These results are discussed concerning the mechanism of specific cell migration during amphibian gastrulation.

An Inverse Relation Between Cell Density and the Number of Microvilli in Cultures of BHK 21 Hamster Fibroblasts

1970 ◽  
Vol 7 (3) ◽  
pp. 695-709
Author(s):  
C. H. O'NEILL ◽  
E. A. C. FOLLETT
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Monolayer Culture ◽  
Cell Contact ◽  
Inverse Relation ◽  
Culture Density ◽  
Microscope Technique ◽  
The Relationship ◽  
Number Of Cells ◽  
Scanning Electron

The relationship between culture density and the number of microvilli on the cell surface has been studied using BHK21 cells in established monolayer culture. The number of microvilli can be estimated quantitatively by a scanning electron-microscope technique. It can be increased by applying specific antiserum, but whether antibody is applied or not a significant number of cells regularly bear microvilli. This number is characteristic of the culture density. In sparse cultures above a certain minimum density it is relatively high, and in confluent cultures it is much reduced. These results indicate that microvilli may be inhibited by cell contact.

scholarly journals Units of chromosome replication and packing

1983 ◽  
Vol 64 (1) ◽  
pp. 179-193
Author(s):  
A.M. Mullinger ◽  
R.T. Johnson
Keyword(s):  
Spatial Distribution ◽  
Light Microscope ◽  
Individual Cell ◽  
S Phase ◽  
Scanning Electron Micrographs ◽  
Metaphase Chromosomes ◽  
Impregnation Technique ◽  
Osmium Impregnation ◽  
The Relationship ◽  
Scanning Electron

Fusion between mitotic and S-phase cells induces the formation of prematurely condensed chromosomes (PCC) in the interphase partner. Viewed in the light microscope, S-phase PCC derived from the Indian muntjac appear to be fragmented and heterogeneous. In scanning electron micrographs prepared by an osmium impregnation technique, which avoids the need to sputter-coat the specimen, the S-phase fragments derived from an individual cell are resolved into about 1000 fibre aggregates, together with more dispersed fibres. Aggregates are roughly spherical and vary in diameter between about 0.25 and 1.6 micron. The spatial distribution of the aggregates shows some order: chains of single aggregates and, less commonly, duplicated chains occur. Regions of the PCC where the fibres are more dispersed are considered to be likely candidates for sites of replication at the time of fusion. The relationship between the condensed aggregate structure of the S-phase PCC and replication clusters is discussed, and also the assembly of aggregates to form metaphase chromosomes.

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