scholarly journals THE OWN STRESSES INFLUENCE ON SCALE EFFECT IN CONCRETE

2019 ◽  
Vol 2 (53) ◽  
pp. 79-84
Author(s):  
Aleksey Fenko ◽  
Ilona Yurko ◽  
Anton Hasenko ◽  
Oleksandr Krupchenko ◽  
Pavlo Yurko
Keyword(s):  
Cross Section ◽  
Scale Effect ◽  
Experimental Technique ◽  
Experimental Studies

The experimental technique and the experiment results on the influence of own stresses unevenly distributed over crosssection on materials strength and on scale effect are presented. The reasons for the occurrence and distribution of suchinfluence are analyzed. Based on the experiments results on fragile duralumin samples, the inevitability of influencing onscale effect in concrete during compression stresses, which are caused by unevenly shrinkage over cross section was proved.Possible reasons for the different (sometimes opposing) results of experimental studies of various authors on scale effect inconcrete in compression are explained. The influence of own stresses unevenly distributed over cross section on scale effectin concrete during compression, depending on samples size and concrete age, is analyzed in detail

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

scholarly journals Hydraulic Transients in Viscoelastic Pipeline System with Sudden Cross-Section Changes

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4071
Author(s):  
Michał Kubrak ◽  
Agnieszka Malesińska ◽  
Apoloniusz Kodura ◽  
Kamil Urbanowicz ◽  
Michał Stosiak
Keyword(s):  
Numerical Model ◽  
Cross Section ◽  
Laboratory Data ◽  
Experimental Studies ◽  
Distribution Networks ◽  
Water Hammer ◽  
Fluid Distribution ◽  
Pipeline System ◽  
Hydraulic Transients ◽  
Single Pipe

It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.

scholarly journals Photoionization Cross-Sections of Carbon-Like N+ Near the K-Edge (390–440 eV)

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Jean-Paul Mosnier ◽  
Eugene T. Kennedy ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Studies ◽  
Photoionization Cross Section ◽  
Theoretical Work ◽  
Rydberg Series ◽  
R Matrix ◽  
Resonance Strengths ◽  
Nitrogen Ion

High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398–403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415–440 eV photon region 1s⟶(1s2s22p2 4P)np and 1s⟶(1s2s22p2 2P)np resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.

scholarly journals Extracting Hypernuclear Properties from the (e, e′K+) Cross Section

Particles ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 194-204
Author(s):  
Omar Benhar
Keyword(s):  
Cross Section ◽  
Experimental Studies ◽  
Strong Interactions ◽  
Many Body ◽  
Kaon Production ◽  
Many Body Theory ◽  
Independent Analysis ◽  
Dense Nuclear Matter ◽  
Proton Knockout ◽  
Comprehensive Framework

Experimental studies of hypernuclear dynamics, besides being essential for the understanding of strong interactions in the strange sector, have important astrophysical implications. The observation of neutron stars with masses exceeding two solar masses poses a serious challenge to the models of hyperon dynamics in dense nuclear matter, many of which predict a maximum mass incompatible with the data. In this paper, it is argued that valuable new insight can be gained from the forthcoming extension of the experimental studies of kaon electro production from nuclei to include the 208Pb(e,e′K+)Λ208Tl process. A comprehensive framework for the description of kaon electro production, based on factorization of the nuclear cross section and the formalism of the nuclear many-body theory, is outlined. This approach highlights the connection between the kaon production and proton knockout reactions, which will allow us to exploit the available 208Pb(e,e′p)207Tl data to achieve a largely model-independent analysis of the measured cross section.

An investigation of effects of level density models and gamma ray strength functions on cross-section calculations for the production of 90Y, 153Sm, 169Er, 177Lu and 186Re therapeutic radioisotopes via (n,γ) reactions

2019 ◽  
Vol 108 (1) ◽  
pp. 11-17
Author(s):  
Mert Şekerci ◽  
Hasan Özdoğan ◽  
Abdullah Kaplan
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Production Cross Section ◽  
Gamma Ray ◽  
Production Cross ◽  
Level Density ◽  
Experimental Studies ◽  
Level Density Models ◽  
Strength Functions ◽  
Cancer Diseases

Abstract One of the methods used to treat different cancer diseases is the employment of therapeutic radioisotopes. Therefore, many clinical, theoretical and experimental studies are being carried out on those radioisotopes. In this study, the effects of level density models and gamma ray strength functions on the theoretical production cross-section calculations for the therapeutic radioisotopes 90Y, 153Sm, 169Er, 177Lu and 186Re in the (n,γ) route have been investigated. TALYS 1.9 code has been used by employing different level density models and gamma ray strength functions. The theoretically obtained data were compared with the experimental data taken from the literature. The results are presented graphically for better interpretation.

Moderate Reynolds Number Mixing in a T-Channel

2010 ◽  
Author(s):  
Susan Thomas ◽  
Tim Ameel
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Large Body ◽  
Experimental Studies ◽  
Numerical Work ◽  
Moderate Reynolds Number ◽  
Wide Range ◽  
Particle Imaging ◽  
Experimental Trials

An experimental investigation of water flow in a T-shaped channel with rectangular cross section (20 × 20 mm inlet ID and 20 × 40 mm outlet ID) has been conducted for a Reynolds number Re range of 56 to 422, based on inlet diameter. Dynamical conditions and the T-channel geometry of the current study are applicable to the microscale. This study supports a large body of numerical work, and resolution and the interrogation region are extended beyond previous experimental studies. Laser induced fluorescence (LIF) and particle imaging velocimetry (PIV) are used to characterize flow behaviors over the broad range of Re where realistic T-channels operate. Scalar structures previously unresolved in the literature are presented. Special attention is paid to the unsteady flow regimes that develop at moderate Re, which significantly impact mixing but are not yet well characterized or understood. An unsteady symmetric topology, which develops at higher Re and negatively impacts mixing, is presented, and mechanisms behind the wide range of mixing qualities predicted for this regime are explained. An optimal Re operating range is identified based on multiple experimental trials.

scholarly journals Experimental Studies on Scale Effect of unstable Flow around the Stern

1978 ◽  
Vol 1978 (144) ◽  
pp. 21-29 ◽  
Author(s):  
Toshiichi Seo ◽  
Yukichi Nagashima ◽  
Masanobu Sudo ◽  
Isao Ashidate ◽  
Ryosuke Fujimoto ◽  
...  
Keyword(s):  
Scale Effect ◽  
Experimental Studies ◽  
Unstable Flow

scholarly journals Experimental study on the thermal behaviour of fire exposed slim-floor beams

2018 ◽  
Author(s):  
Vicente Albero ◽  
Ana Espinós ◽  
Enrique Serra ◽  
Manuel L. Romero ◽  
Antonio Hospitaler
Keyword(s):  
Cross Section ◽  
Thermal Behaviour ◽  
Thermal Model ◽  
Elevated Temperatures ◽  
Experimental Studies ◽  
Composite Beams ◽  
Technical Equipment ◽  
Design Code ◽  
Special Configuration ◽  
The Cross

Steel-concrete composite beams embedded in floors (slim-floors) offer various advantages such as the floor thickness reduction or the ease of installation of under-floor technical equipment. However, this typology presents important differences in terms of thermal behaviour, as compared to other composite beams, when exposed to elevated temperatures. These differences are due to their special configuration, being totally contained within the concrete floor depth. Moreover, the current European fire design code for composite steel-concrete structures (EN 1994-1-2) does not provide any simplified thermal model to evaluate the temperature evolution of each slim-floor part during a fire. Additionally, only a few experimental studies can be found which may help understand the thermal behaviour of these composite beams. This paper presents an experimental investigation on the thermal behaviour of slim-floor beams. Electrical radiative panels were used in the test setup to produce the thermal heating. The thermal gap between the lower flange of the steel profile and the bottom steel plate was studied, being found to be one of the most influential elements over the cross-section temperature gradient. The experimental campaign was developed by varying the cross-section configuration in order to evaluate the influence of this parameter over the slim-floor thermal behavior. Finally, the experiments carried out were used to develop and calibrate a finite element thermal model which may help in further research on the thermal behaviour of slim-floor composite beams.

$e^+e^-\gamma$ production at photon-photon colliders at complete electroweak NLO accuracy

2021 ◽  
Author(s):  
He-Yi Li ◽  
Ren-You Zhang ◽  
Wen-Gan Ma ◽  
Yi Jiang ◽  
Xiao-Zhou Li
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Linear Collider ◽  
Experimental Studies ◽  
High Energy ◽  
Radiative Corrections ◽  
High Energy Gamma ◽  
Electroweak Radiative Corrections ◽  
Energy Gamma ◽  
Beam Luminosity

Abstract We present the full NLO electroweak radiative corrections to $e^+e^-\gamma$ production in $\gamma\gamma$ collision, which is an ideal channel for calibrating the beam luminosity of Photon Linear Collider. We analyse the dependence of the total cross section on the beam colliding energy, and investigate the kinematic distributions of final particles at various initial photon beam polarizations at EW NLO accuracy. The numerical results show that the EW relative corrections to the total cross section are non-negligible and become more and more significant as the increase of the beam colliding energy, even can exceed $-10\%$ in $\text{J} = 2$ $\gamma\gamma$ collision at $\sqrt{\hat{s}}=1~ \text{TeV}$. Such EW corrections are very important and should be taken into consideration in precision theoretical and experimental studies at high-energy $\gamma\gamma$ colliders.

Reaction cross section calculations via second beta decay using the activation method for the p-process

2019 ◽  
Vol 97 (11) ◽  
pp. 1206-1209
Author(s):  
Ezgi Tantoğlu ◽  
Nalan Özkan ◽  
R. Taygun Güray
Keyword(s):  
Beta Decay ◽  
Cross Section ◽  
Cross Sections ◽  
Half Life ◽  
Reaction Cross Section ◽  
Experimental Studies ◽  
Reaction Cross ◽  
Activation Method ◽  
Alternative Method ◽  
The Cross

There are 35 proton-rich isotopes between 74Se and 196Hg that cannot be synthesized through neutron captures and β− decays (s- and r-processes). A third process is therefore required for the production of these nuclei, the so-called p-process. The abundance and the origin of the p-nuclei are still not fully understood even though significant experimental and theoretical efforts in astrophysical modeling have been expended in the last two decades. The experimental studies with the activation method to measure cross sections of the relevant reactions have some limitations: the reaction product must be radioactive, should have an appropriate half-life, and its decay should be followed by proper γ-radiations. If the cross section cannot be calculated with the radiation followed by the first beta decay of the product, it can be measured using the second beta decay as an alternative method. In this study, the method and candidate reactions for the cross-section measurements via the second beta decay of the reaction product using the activation method are discussed.

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