Infiltration into columns of swelling soil as studied by high speed photography

Soil Research ◽  
1970 ◽  
Vol 8 (2) ◽  
pp. 195 ◽  
Author(s):  
N Collis-George ◽  
R Lal
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
Motion Pictures ◽  
Original Structure ◽  
High Speed Photography ◽  
Surface Layers ◽  
Depth Zone ◽  
Swelling Soil

Columns of aggregates of a soil, which slakes into microaggregates of about 30 � diameter as well as swelling on quick wetting, were examined by high speed photography during infiltration. Because of the collapse of the original structure of surface layers, the supply of water to deeper layers is restricted. Examination of motion pictures and magnified stills for the depth zone just below the collapsed surface layer provides a description of the phenomena occurring during the advance of the front. These phenomena are discussed in terms of limitations of the procedure used, the mechanism of wetting, the displacement of particles, infiltration behaviour, and the nature of swelling and slaking in these systems.

Study of medium-carbon steels structure after electromechanical processing

2020 ◽  
pp. 473-477
Author(s):  
Yu.S. Ivanova ◽  
V.N. Zaripov ◽  
Ngo Van Tuyen ◽  
Myat Soe Lwin ◽  
Ye Kyaw Oo
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
Heat Stability ◽  
Carbon Steels ◽  
Original Structure ◽  
Surface Microhardness ◽  
Medium Carbon ◽  
Wide Range ◽  
Medium Carbon Steels ◽  
40Cr Steel

The results of the microstructure and microhardness of the surface layer of medium-carbon 40Cr, 38CrNi3MoA steels after electromechanical processing are presented. The results of tests on the heat stability of samples made of 38CrNi3MoA steel when they are consistently heated from 150 to 550 °C, in the temperature range of 50 °C are presented. The samples are heated in muffle furnaces with exposure at each temperature of 10 min and cooled in air. The heat stability of the surface layer after electromechanical processing is controlled by changes in microhardness. The results of the microstructure indicate the formation of fine martensite and retained austenite in the upper layers of the quenching zones. High speed heating of local volume of the surface with parallel thermoplastic shaping by work-hardening tool and following high-intensity cooling through heat rejection in deep into work material take place in the time of electromechanical processing. The structure of sorbite is form in the overlap zone of electro-mechanical hardening and in the transition near original structure section. The average surface microhardness of the 40Cr steel samples before hardening is HV = 2000...2400 MPa, after electromechanical hardening — HV = 6640 MPa, and the 38CrNi3MoA steel samples before hardening is HV = 2000...2200 MPa, after electromechanical hardening — HV = 7060 MPa. The graded layer has hardening depth to 0.8 mm with stepwise degradation of hardness is detected. The research results show that using electromechanical processing in the manufacture of wide range of parts in order to increase the wear resistance of the surface layer.

Effect of Laser Surface Melting on Structure and Properties of a High Speed Tool Steel

2011 ◽  
Vol 291-294 ◽  
pp. 1365-1368 ◽  
Author(s):  
Mirosław Bonek ◽  
Grzegorz Matula ◽  
Leszek Adam Dobrzański
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
Steel Surface ◽  
Structure Refinement ◽  
High Speed Steel ◽  
Laser Surface ◽  
Structure And Properties ◽  
Surface Layers ◽  
Metal Base ◽  
Protection Method

The purpose of this research paper is focused on the high speed steel surface layers improvement properties using HPDL laser. The paper present laser surface technologies, investigation of structure and properties of the high speed steel alloying with carbides using high power diode laser HPDL. Investigation indicate the influence of the alloying carbides on the structure and properties of the surface layer of investigated steel depending on the kind of alloying carbides and power implemented laser (HPDL). In the effect of laser alloying with powder of carbides occurs size reduction of microstructure as well as dispersion hardening through fused in but partially dissolved carbides and consolidation through enrichment of surface layer in alloying additions coming from dissolving carbides. Introduced particles of carbides and in part remain undissolved, creating conglomerates being a result of fusion of undissolved powder grains into molten metal base. The structural mechanism was determined of surface layers development, effect was studied of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer, and especially on its hardness, abrasive wear resistance, and roughness. It has the important cognitive significance and gives grounds to the practical employment of these technologies for forming the surfaces of new tools and regeneration of the used ones.

Formation and Evolution of Hydrated Surface Layers of Apatites

2005 ◽  
Vol 284-286 ◽  
pp. 3-6 ◽  
Author(s):  
Diane Eichert ◽  
Christèle Combes ◽  
Christophe Drouet ◽  
Cristian Rey
Keyword(s):  
Surface Layer ◽  
Aqueous Media ◽  
Ionic Species ◽  
Biological Behavior ◽  
Original Structure ◽  
Surface Layers ◽  
Carbonate Ions ◽  
Hydrated Layer ◽  
Spectroscopic Characteristics ◽  
Formation And Evolution

Nanocrystalline apatites exhibit a very fragile structured hydrated surface layer which is only observed in aqueous media. This surface layer contains mobile ionic species which can be easily exchanged with ions from the surrounding fluids. Although the precise structure of this surface layer is still unknown, it presents very specific spectroscopic characteristics. The structure of the hydrated surface layer depends on the constitutive mineral ions: ion exchanges of HPO4 2- ions by CO3 2- ions or of Ca2+ by Mg2+ ions result in a de-structuration of the hydrated layer and modifies its spectroscopic characteristics. However, the original structure can be retrieved by reverse exchange reaction. These alterations do not seem to affect the apatitic lattice. Stoichiometric apatite also shows HPO4 2- on their surface due to a surface hydrolysis after contact with aqueous solutions. Ion exchange is also observed and the environments of the surface carbonate ions seem analogous to that observed in nanocrystalline apatites. The formation of a hydrated layer in aqueous media appears to be a property common to apatites which has to be taken into account in their reactivity and biological behavior.

scholarly journals Study of Physical and Mechanical Properties of Steel During Grinding and Sharpening

2020 ◽  
Vol 3 (1) ◽  
pp. 128-140
Author(s):  
Witold Biały ◽  
Tatiana Nikolajevna Ivanova ◽  
Jozef Žarnovský ◽  
Juraj Ružbarský
Keyword(s):  
Surface Layer ◽  
Thermal Process ◽  
High Speed ◽  
Cutting Speed ◽  
Physical And Mechanical Properties ◽  
Thermal Processes ◽  
Surface Layers ◽  
Cooling Fluid ◽  
Heating And Cooling ◽  
The Relationship

AbstractA direct influence on the physical and mechanical state of the surface layer of wedge-shaped plates made of 8KHF steel is exerted by heat generation processes developing in the zone of a high-speed thermal process. Research on the influence of the parameters of a high-speed thermal process on the change in the structure of 8KHF steel (GOST 5950-2000 Russia, standard PN/H 85023 brand NCV1 Poland) was fulfilled. It allowed studying the nature of the change in the microstructure depending on short-term heating to various temperatures and rapid cooling. As a result, critical points of the beginning and the end of structural transformations during heating were determined. Research on thermal processes in a high-speed thermal process made it possible to establish regularities of influence of cutting speed, source speed, contact area, coolant properties and heat transfer coefficient on the temperature and rate of thermal processes in surface layers, as well as their impact on the depth of heating to a certain temperature. The study also allowed us to show the relationship between temperature and rates of heating and cooling. The solution to this problem, taking into account the action of the cooling fluid, gives the opportunity to bring the picture of the development of thermal processes closer to real conditions and makes it possible to reasonably predict the structural state of the surface layer of wedge-shaped parts made of 8KHF steel under various conditions of a high-speed thermal process.

Crack divergence phenomena in tempered glass

2020 ◽  
Vol 13 (3) ◽  
pp. 115-129
Author(s):  
Shin’ichi Aratani
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Glass Plate ◽  
Acute Angle ◽  
Divergence Angle ◽  
High Speed Photography ◽  
Tempered Glass ◽  
Thick Glass

High speed photography using the Cranz-Schardin camera was performed to study the crack divergence and divergence angle in thermally tempered glass. A tempered 3.5 mm thick glass plate was used as a specimen. It was shown that two types of bifurcation and branching existed as the crack divergence. The divergence angle was smaller than the value calculated from the principle of optimal design and showed an acute angle.

Experimental study of hydrodynamic effects in the inverse water hydrocarbon emulsions flow in microchannels

2016 ◽  
Vol 11 (1) ◽  
pp. 30-37 ◽  
Author(s):  
A.A. Rakhimov ◽  
A.T. Akhmetov
Keyword(s):  
High Speed ◽  
Petroleum Industry ◽  
Chemical Compounds ◽  
High Viscosity ◽  
Blocking Effect ◽  
High Speed Photography ◽  
Simple Chemical ◽  
Reported Study ◽  
Dynamic Blocking ◽  
Hydrodynamic Effects

The paper presents results of hydrodynamic and rheological studies of the inverse water hydrocarbon emulsions. The success of the application of invert emulsions in the petroleum industry due, along with the high viscosity of the emulsion, greatly exceeding the viscosity of the carrier phase, the dynamic blocking effect, which consists in the fact that the rate of flow of emulsions in capillary structures and cracks falls with time to 3-4 orders, despite the permanent pressure drop. The reported study shows an increase in viscosity with increasing concentration or dispersion of emulsion. The increase in dispersion of w/o emulsion leads to an acceleration of the onset of dynamic blocking. The use of microfluidic devices, is made by soft photolithography, along with high-speed photography (10,000 frames/s), allowed us to see in the blocking condition the deformation of the microdroplets of water in inverse emulsion prepared from simple chemical compounds.

scholarly journals Prey Capturing Dynamics and Nanomechanically Graded Cutting Apparatus of Dragonfly Nymph

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Lakshminath Kundanati ◽  
Prashant Das ◽  
Nicola M. Pugno
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Speed ◽  
Prey Capture ◽  
High Speed Photography ◽  
Sensory Organs ◽  
Dragonfly Nymph ◽  
Drag Forces ◽  
Predatory Insects ◽  
Dragonfly Nymphs

Aquatic predatory insects, like the nymphs of a dragonfly, use rapid movements to catch their prey and it presents challenges in terms of movements due to drag forces. Dragonfly nymphs are known to be voracious predators with structures and movements that are yet to be fully understood. Thus, we examine two main mouthparts of the dragonfly nymph (Libellulidae: Insecta: Odonata) that are used in prey capturing and cutting the prey. To observe and analyze the preying mechanism under water, we used high-speed photography and, electron microscopy. The morphological details suggest that the prey-capturing labium is a complex grasping mechanism with additional sensory organs that serve some functionality. The time taken for the protraction and retraction of labium during prey capture was estimated to be 187 ± 54 ms, suggesting that these nymphs have a rapid prey mechanism. The Young’s modulus and hardness of the mandibles were estimated to be 9.1 ± 1.9 GPa and 0.85 ± 0.13 GPa, respectively. Such mechanical properties of the mandibles make them hard tools that can cut into the exoskeleton of the prey and also resistant to wear. Thus, studying such mechanisms with their sensory capabilities provides a unique opportunity to design and develop bioinspired underwater deployable mechanisms.

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