Analytical relationship for determining the relaxation losses of specific momentum [in a supersonic nozzle]

The mechanical properties of a complex composite material formed by steel and hardened concrete, are studied. A technique of operative quality control of new credible concrete and reinforcement, both in laboratory and field conditions is developed for determination of the strength and strain characteristics of materials, as well as cohesion forces determining their joint operation under load. The design of the mobile unit is presented. The unit provides a possibility of changing the direction of loading and testing the reinforced element of the given shape both for tension and compression. Moreover, the nomenclature of testing equipment and the number of molds for manufacturing concrete samples substantially decrease. Using the values of forcing resulting in concrete cracking when the joint work of concrete and reinforcement is disrupted the values of the inherent stresses and strains attributed to the concrete shrinkage are determined. An analytical relationship between the forces and deformations of the reinforced concrete sample with central reinforcement is derived for axial tension and compression, with allowance for strains and stresses in the reinforcement and concrete resulted from concrete shrinkage. The results of experimental studies are presented, including tension diagrams and diagrams of developing axial deformations with an increase in the load under the central loading of the reinforced elements. A methodology of accounting for stresses and deformations resulted from concrete shrinkage is developed. The applicability of the derived analytical relationships between stresses and deformations on the material diagrams to calculations of the reinforced concrete structures in the framework of the deformation model is estimated.

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Methodology for Increasing the Efficiency of Dynamic Process Calculations in Elastic Elements of Complex Engineering Constructions

Electronics ◽

10.3390/electronics10010040 ◽

2020 ◽

Vol 10 (1) ◽

pp. 40

Author(s):

Andriy Andrukhiv ◽

Maria Sokil ◽

Solomiia Fedushko ◽

Yuriy Syerov ◽

Yaryna Kalambet ◽

...

Keyword(s):

Dynamic Process ◽

Granular Media ◽

Homogeneous Medium ◽

Dynamic Processes ◽

Analytical Relationship ◽

Operational Parameters ◽

Protective Capacity ◽

Vibration Displacement ◽

Complex Engineering ◽

Elastic Elements

This study deals with a methodology for increasing the efficiency of dynamic process calculations in elastic elements of complex engineering constructions. We studied the complex dynamic processes in a simple engineering construction, a mechanical system of an elastic body–continuous flow of homogeneous medium. The developed methodology is based on the use of a priori information on some of the vibrations forms, the construction of a “simplified” mathematical model of system dynamics, and the obtaining of an analytical relationship that describe the overall range of factors on the elastic vibrations of system. The methodology is used for cases of complex vibrations of elastic bodies, and the obtained results can serve as a basis for choosing the main technological and operational parameters of elastic elements of mechanisms and machines that perform complex vibrations. The results obtained in this work are the basis for calculating the blast effect on the elements of protective structures in order to increase their protective capacity by improving the method of their attachment or by using additional reinforcement, buff load effects on the elements of drilling strings and dynamic processes that occur during surface strengthening by work hardening in order to avoid resonance phenomena, and technological processes of vibration displacement or vibration separation of granular media.

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Directional Plasmonic Excitation by Helical Nanotips

Nanomaterials ◽

10.3390/nano11051333 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1333

Author(s):

Leeju Singh ◽

Nicolò Maccaferri ◽

Denis Garoli ◽

Yuri Gorodetski

Keyword(s):

Surface Plasmon ◽

Single Scattering ◽

Coupling Factor ◽

Metallic Surface ◽

Phase Matching ◽

Plasmon Excitation ◽

Surface Plasmon Excitation ◽

Specific Momentum ◽

Plasmon Polaritons ◽

Strong Spin

The phenomenon of coupling between light and surface plasmon polaritons requires specific momentum matching conditions. In the case of a single scattering object on a metallic surface, such as a nanoparticle or a nanohole, the coupling between a broadband effect, i.e., scattering, and a discrete one, such as surface plasmon excitation, leads to Fano-like resonance lineshapes. The necessary phase matching requirements can be used to engineer the light–plasmon coupling and to achieve a directional plasmonic excitation. Here, we investigate this effect by using a chiral nanotip to excite surface plasmons with a strong spin-dependent azimuthal variation. This effect can be described by a Fano-like interference with a complex coupling factor that can be modified thanks to a symmetry breaking of the nanostructure.

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Multifractality through Non-Markovian Stochastic Processes in the Scale Relativity Theory. Acute Arterial Occlusions as Scale Transitions

Entropy ◽

10.3390/e23040444 ◽

2021 ◽

Vol 23 (4) ◽

pp. 444

Author(s):

Nicolae Dan Tesloianu ◽

Lucian Dobreci ◽

Vlad Ghizdovat ◽

Andrei Zala ◽

Adrian Valentin Cotirlet ◽

...

Keyword(s):

Stochastic Processes ◽

Standard Form ◽

Momentum Conservation ◽

Relativity Theory ◽

Horizontal Pipe ◽

Scale Transition ◽

Theory Of Motion ◽

Multifractal Theory ◽

Scale Relativity ◽

Specific Momentum

By assimilating biological systems, both structural and functional, into multifractal objects, their behavior can be described in the framework of the scale relativity theory, in any of its forms (standard form in Nottale’s sense and/or the form of the multifractal theory of motion). By operating in the context of the multifractal theory of motion, based on multifractalization through non-Markovian stochastic processes, the main results of Nottale’s theory can be generalized (specific momentum conservation laws, both at differentiable and non-differentiable resolution scales, specific momentum conservation law associated with the differentiable–non-differentiable scale transition, etc.). In such a context, all results are explicated through analyzing biological processes, such as acute arterial occlusions as scale transitions. Thus, we show through a biophysical multifractal model that the blocking of the lumen of a healthy artery can happen as a result of the “stopping effect” associated with the differentiable-non-differentiable scale transition. We consider that blood entities move on continuous but non-differentiable (multifractal) curves. We determine the biophysical parameters that characterize the blood flow as a Bingham-type rheological fluid through a normal arterial structure assimilated with a horizontal “pipe” with circular symmetry. Our model has been validated based on experimental clinical data.

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Estimation of the G2P Design Storm from a Rainfall Convectivity Index

Water ◽

10.3390/w13141943 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1943

Author(s):

Rosario Balbastre-Soldevila ◽

Rafael García-Bartual ◽

Ignacio Andrés-Doménech

Keyword(s):

Shape Parameter ◽

Rainfall Intensity ◽

Analytical Relationship ◽

Urban Drainage ◽

Practical Application ◽

Resolution Time ◽

Simple Method ◽

Design Storm ◽

Intensity Duration Frequency ◽

Two Parameter

The two-parameter gamma function (G2P) design storm is a recent methodology used to obtain synthetic hyetographs especially developed for urban hydrology applications. Further analytical developments on the G2P design storm are presented herein, linking the rainfall convectivity n-index with the shape parameter of the design storm. This step can provide a useful basis for future easy-to-handle rainfall inputs in the context of regional urban drainage studies. A practical application is presented herein for the case of Valencia (Spain), based on high-resolution time series of rainfall intensity. The resulting design storm captures certain internal statistics and features observed in the fine-scale rainfall intensity historical records. On the other hand, a direct, simple method is formulated to derivate the design storm from the intensity–duration–frequency (IDF) curves, making use of the analytical relationship with the n-index.

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Enhanced Estimation of Root Zone Soil Moisture at 1 km Resolution Using SMAR Model and MODIS-Based Downscaled AMSR2 Soil Moisture Data

Sensors ◽

10.3390/s21155211 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5211

Author(s):

Maedeh Farokhi ◽

Farid Faridani ◽

Rosa Lasaponara ◽

Hossein Ansari ◽

Alireza Faridhosseini

Keyword(s):

Soil Moisture ◽

Prediction Models ◽

Surface Soil ◽

Root Zone ◽

Analytical Relationship ◽

Moisture Profile ◽

Essential Variable ◽

Potential Benefits ◽

Spatio Temporal ◽

Hydrological Prediction

Root zone soil moisture (RZSM) is an essential variable for weather and hydrological prediction models. Satellite-based microwave observations have been frequently utilized for the estimation of surface soil moisture (SSM) at various spatio-temporal resolutions. Moreover, previous studies have shown that satellite-based SSM products, coupled with the soil moisture analytical relationship (SMAR) can estimate RZSM variations. However, satellite-based SSM products are of low-resolution, rendering the application of the above-mentioned approach for local and pointwise applications problematic. This study initially attempted to estimate SSM at a finer resolution (1 km) using a downscaling technique based on a linear equation between AMSR2 SM data (25 km) with three MODIS parameters (NDVI, LST, and Albedo); then used the downscaled SSM in the SMAR model to monitor the RZSM for Rafsanjan Plain (RP), Iran. The performance of the proposed method was evaluated by measuring the soil moisture profile at ten stations in RP. The results of this study revealed that the downscaled AMSR2 SM data had a higher accuracy in relation to the ground-based SSM data in terms of MAE (↓0.021), RMSE (↓0.02), and R (↑0.199) metrics. Moreover, the SMAR model was run using three different SSM input data with different spatial resolution: (a) ground-based SSM, (b) conventional AMSR2, and (c) downscaled AMSR2 products. The results showed that while the SMAR model itself was capable of estimating RZSM from the variation of ground-based SSM data, its performance increased when using downscaled SSM data suggesting the potential benefits of proposed method in different hydrological applications.

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