scholarly journals Interfacial Phenomena at the Interface in the System «Carbon Primary Materials-Water Solutions of Surfactants» for Cement Materials

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 556
Author(s):  
Svetlana Shekhovtsova ◽  
Evgenii Korolev
Keyword(s):  
Carbon Nanoparticles ◽  
Small Area ◽  
Dispersive Medium ◽  
Interfacial Phenomena ◽  
Hydrophilic Surface ◽  
Two Dimensional ◽  
Sustainable Concrete ◽  
Dispersion Systems ◽  
Adsorption Layers ◽  
Primary Materials

The formation of sustainable concrete is directly relaed to the intensity of the processes occurring at the interface of phases. The study of the surface properties of CNPLUS carbon nanotubes in solutions of various plasticizers was carried out by measuring and calculating adsorption. The applicability of the adsorption value is for forecasting both the efficiency of dispersion and aggregative and sedimentative stability of the obtained dispersion systems. It was stated that two-dimensional pressure arising at the interface of adsorption layers in the dispersive medium with the surfactant Tensafor 2553.2 J/m2 is sufficient to overcome adhesive strength on a small area of the localized contact of carbon nanoparticles CNPLUS, which explains the peptization and stabilization of the particles’ surface. It was established that full stabilization of nanoparticles in the aqueous dispersive medium could be ensured only by means of soap-like surfactants, with the compound potassium naphthalene sulfonate (Tensafor). It ensures formation of the micelle-like structure in coagulation layers that forms a structural and mechanical barrier with the external hydrophilic surface. This leads to the increase in the ultimate tensile strength of the concrete grout specimens by 38%.

scholarly journals I. On the waves produced by a single impulse in water of any depth, or in a dispersive medium

1887 ◽  
Vol 42 (251-257) ◽  
pp. 80-83 ◽  
Keyword(s):  
Wave Velocity ◽  
Dispersive Medium ◽  
Wave Length ◽  
Periodic Waves ◽  
Two Dimensional ◽  
Group A ◽  
Two Sides ◽  
The Waves

For brevity and simplicity consider only the case of two-dimensional motion . All that it is necessary to know of the medium is the relation between the wave-velocity and the wave-length of an endless procession of periodic waves. The result of our work will show us that the velocity of progress of a zero, or maximum, or minimum, in any part of a varying group of waves, is equal to the velocity of progress of periodic waves of wave-length equal to a certain length, which may be defined as the wave-length in the neighbourhood of the particular point looked to in the group (a length which will generally be intermediate between the distances from the point considered to its next-neighbour corresponding points on its two sides).

Thermal Response of a Magneto-Resistive Head When it Flies Over an Asperity

1999 ◽  
Vol 121 (4) ◽  
pp. 975-979 ◽  
Author(s):  
Shuyu Zhang ◽  
David B. Bogy
Keyword(s):  
Small Area ◽  
Temperature Response ◽  
Thermal Response ◽  
Air Bearing ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model ◽  
Current Value ◽  
Head Temperature ◽  
Bearing System

A two-dimensional model is developed for the heat transfer in a magneto-resistive (MR) head-air bearing system. Using this model, the MR head temperature response is studied for various cases. It is found that the temperature in the head depends on the current through it and the change is only significant within a small area around the MR transducer at the trailing edge. With a typical current value (say 13 mA), the MR head temperature is about 25°C higher than the ambient temperature. When the slider flies over an asperity without contact, the MR temperature fluctuation follows that of the air bearing spacing, which is caused by the cooling effect of the air bearing.

CT Multiscan: Using Small Area Detectors to Image Large Components

1995 ◽  
Author(s):  
E. A. Sivers ◽  
W. A. Ellingson ◽  
S. A. Snyder ◽  
D. A. Holloway
Keyword(s):  
Small Area ◽  
Dynamic Range ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Large Component ◽  
X Ray ◽  
Area Detector ◽  
Longest Path ◽  
Ceramic Components ◽  
X Ray Computed

The small size and dynamic range of the best two-dimensional X-ray detectors are impediments to the use of three-dimensional X-ray computed tomography (3D-XRCT) for 100% inspection of large ceramic components. The most common industrial 3D-XRCT systems use a “rotate-only” geometry in which the X-ray source and the area detector remain stationary while the component placed between them is rotated through 360°. This configuration offers the highest inspection speed and the best utilization of X-ray dose, but requires that the component be small enough to fit within the X-ray/detector “cone.” Also, if the object is very dense, the ratio of an unattenuated X-ray signal to that through the longest path in the component may exceed the dynamic range of the detector. To some extent, both of these disadvantages can be overcome by using “Multiscan CT,” i.e., scanning small overlapping regions of a large component separately while maximizing the X-ray dose to each. The overlapping scans can then be combined seamlessly into a single scan with optimal contrast.

scholarly journals Laser-Induced Thermography for Quantitative Detection of Cracks in Building Materials

Proceedings ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 25
Author(s):  
Lorenzo Palombi ◽  
Gabriele Inglese ◽  
Valentina Raimondi ◽  
Roberto Olmi
Keyword(s):  
Small Area ◽  
Building Materials ◽  
Thermal Image ◽  
Laser Source ◽  
Quantitative Detection ◽  
Sharp Change ◽  
Two Dimensional ◽  
Dimensional Distribution ◽  
Active Technique ◽  
Deep Fractures

Laser-induced thermography is a an active technique using a laser source to heat a very small area on a side of a crack in a building material. The presence of a crack is easily detected as a sharp change in the temperature due to its insulating nature, but no information about its depth is directly available from the thermal image. The method described in this paper uses a heuristic form of the temperature on the surface of the heated specimen, which is transformed to a two-dimensional distribution. Then, a relation is used (called β -tool) between the thermal gap across the crack and the unknown depth of the damage. The purpose is that of making it possible to distinguish between shallow and deep fractures (more than 15mm deep).

Map fragmentation in two- and three-dimensional environments

2013 ◽  
Vol 36 (5) ◽  
pp. 569-570 ◽  
Author(s):  
Homare Yamahachi ◽  
May-Britt Moser ◽  
Edvard I. Moser
Keyword(s):  
Small Area ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Brain Circuits ◽  
Three Dimensional Space

AbstractThe suggestion that three-dimensional space is represented by a mosaic of neural map fragments, each covering a small area of space in the plane of locomotion, receives support from studies in complex two-dimensional environments. How map fragments are linked, which brain circuits are involved, and whether metric is preserved across fragments are questions that remain to be determined.

CT Multiscan: Using Small Area Detectors to Image Large Components

1996 ◽  
Vol 118 (4) ◽  
pp. 711-716 ◽  
Author(s):  
E. A. Sivers ◽  
W. A. Ellingson ◽  
S. A. Snyder ◽  
D. A. Holloway
Keyword(s):  
Small Area ◽  
Dynamic Range ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Large Component ◽  
X Ray ◽  
Area Detector ◽  
Longest Path ◽  
Ceramic Components ◽  
X Ray Computed

The small size and dynamic range of the best two-dimensional X-ray detectors are impediments to the use of three-dimensional X-ray computed tomography (3D-XRCT) for 100 percent inspection of large ceramic components. The most common industrial 3D-XRCT systems use a “rotate-only” geometry in which the X-ray source and the area detector remain stationary while the component placed between them is rotated through 360 deg. This configuration offers the highest inspection speed and the best utilization of X-ray dose, but requires that the component be small enough to fit within the X-ray/detector “cone.” Also, if the object is very dense, the ratio of an unattenuated X-ray signal to that through the longest path in the component may exceed the dynamic range of the detector. To some extent, both of these disadvantages can be overcome by using “Multiscan CT,” i.e., scanning small overlapping regions of a large component separately while maximizing the X-ray dose to each. The over lapping scans can then be combined seamlessly into a single scan with optimal contrast.

Optimization of inner and outer boundaries of beams and plates with holes

1981 ◽  
Vol 16 (4) ◽  
pp. 211-216 ◽  
Author(s):  
A J Durelli ◽  
K Rajaiah
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Small Area ◽  
Outer Boundary ◽  
Central Hole ◽  
Uniform Pressure ◽  
Two Dimensional ◽  
Photoelastic Method ◽  
Simply Supported ◽  
Square Plate

This paper presents optimized shapes of inner and outer boundaries for three specific problems: a long rectangular plate with a central hole subjected to uniaxial tension, a simply-supported slotted beam subjected to a load uniformly distributed over a small area at the centre, and a square plate with a central hole under uniaxial uniform pressure. The two-dimensional photoelastic method is used for optimization. The results indicate a significant reduction in stress concentration factor or in weight, or in both. The examples presented also include cases where the inner and outer boundary stresses are mutually dependent.

Elastic Wave Propagation from Point Excitations on Thin-Walled Cylindrical Shells

1990 ◽  
Vol 112 (3) ◽  
pp. 399-406 ◽  
Author(s):  
A. D. Pierce ◽  
Hyun-Gwon Kil
Keyword(s):  
Wave Propagation ◽  
Dispersive Medium ◽  
Circular Cylindrical Shell ◽  
Exciting Force ◽  
Cylinder Surface ◽  
Two Dimensional ◽  
Phase Velocities ◽  
Unbounded Medium ◽  
Thin Walled ◽  
Analytical Expressions

The circular cylindrical shell is described by equations that govern wave propagation in a two-dimensional homogeneous, but anisotropic and dispersive, medium. The idealization of an unbounded medium is applicable if the source is replaced by a periodic array of forces, the repetition distance being the cylinder circumference. Analytical expressions and calculations are presented for wavefront patterns, amplitude distributions, polarizations, and phase velocities for waves on the cylinder surface. The analysis includes all three possible directions of the exciting force and gives fundamental results that can be superimposed to predict vibration fields resulting from arbitrary excitations.

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