scholarly journals A Complete Postversion of the Three-Body Continuum Distorted Wave-Eikonal Initial State Approximation for Single Ionization of Multielectron Atoms

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
J. M. Monti ◽  
O. A. Fojón ◽  
J. Hanssen ◽  
R. D. Rivarola
Keyword(s):  
Cross Sections ◽  
Main Role ◽  
Distorted Wave ◽  
Initial State ◽  
State Approximation ◽  
Dynamic Screening ◽  
Three Body ◽  
Multielectron Atoms ◽  
The Impact

Single electron ionization of helium targets produced by the impact of fast proton beams is investigated. The postversion of the continuum distorted wave-eikonal initial state into a three-body approximation is reformulated, including the dynamic screening produced by the nonionized electron. This dynamic screening is shown to play a main role in the determination of double differential cross-sections. A good agreement is found with predictions obtained employing the prior version of the model, so that post-prior discrepancies are almost eliminated.

scholarly journals The Impact of Surficial Biochar Treatment on Acute H2S Emissions during Swine Manure Agitation before Pump-Out: Proof-of-the-Concept

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 940 ◽  
Author(s):  
Baitong Chen ◽  
Jacek A. Koziel ◽  
Andrzej Białowiec ◽  
Myeongseong Lee ◽  
Hantian Ma ◽  
...  
Keyword(s):  
Inhalation Exposure ◽  
Swine Manure ◽  
Carbonaceous Material ◽  
Land Application ◽  
Gaseous Emissions ◽  
Total Emission ◽  
Initial State ◽  
H2s Emission ◽  
The Impact

Acute releases of hydrogen sulfide (H2S) are of serious concern in agriculture, especially when farmers agitate manure to empty storage pits before land application. Agitation can cause the release of dangerously high H2S concentrations, resulting in human and animal fatalities. To date, there is no proven technology to mitigate these short-term releases of toxic gas from manure. In our previous research, we have shown that biochar, a highly porous carbonaceous material, can float on manure and mitigate gaseous emissions over extended periods (days–weeks). In this research, we aim to test the hypothesis that biochar can mitigate H2S emissions over short periods (minutes–hours) during and shortly after manure agitation. The objective was to conduct proof-of-the-concept experiments simulating the treatment of agitated manure. Two biochars, highly alkaline and porous (HAP, pH 9.2) made from corn stover and red oak (RO, pH 7.5), were tested. Three scenarios (setups): Control (no biochar), 6 mm, and 12 mm thick layers of biochar were surficially-applied to the manure. Each setup experienced 3 min of manure agitation. Real-time concentrations of H2S were measured immediately before, during, and after agitation until the concentration returned to the initial state. The results were compared with those of the Control using the following three metrics: (1) the maximum (peak) flux, (2) total emission from the start of agitation until the concentration stabilized, and (3) the total emission during the 3 min of agitation. The Gompertz’s model for determination of the cumulative H2S emission kinetics was developed. Here, 12 mm HAP biochar treatment reduced the peak (1) by 42.5% (p = 0.125), reduced overall total emission (2) by 17.9% (p = 0.290), and significantly reduced the total emission during 3 min agitation (3) by 70.4%. Further, 6 mm HAP treatment reduced the peak (1) by 60.6%, and significantly reduced overall (2) and 3 min agitation’s (3) total emission by 64.4% and 66.6%, respectively. Moreover, 12 mm RO biochar treatment reduced the peak (1) by 23.6%, and significantly reduced overall (2) and 3 min total (3) emission by 39.3% and 62.4%, respectively. Finally, 6 mm RO treatment significantly reduced the peak (1) by 63%, overall total emission (2) by 84.7%, and total emission during 3 min agitation (3) by 67.4%. Biochar treatments have the potential to reduce the risk of inhalation exposure to H2S. Both 6 and 12 mm biochar treatments reduced the peak H2S concentrations below the General Industrial Peak Limit (OSHA PEL, 50 ppm). The 6 mm biochar treatments reduced the H2S concentrations below the General Industry Ceiling Limit (OSHA PEL, 20 ppm). Research scaling up to larger manure volumes and longer agitation is warranted.

ANALYSIS OF THE IMPACT OF BIOMATERIAL AND THE TECHNOLOGY OF PROSTHETIC CROWNS MANUFACTURING ON THE CONNECTION WITH VENEERING CERAMICS

Tribologia ◽  
2021 ◽  
Vol 293 (5) ◽  
pp. 17-25
Author(s):  
Anna M. RYNIEWICZ ◽  
Andrzej Ryniewicz ◽  
Łukasz Bojko ◽  
Wojciech Ryniewicz
Keyword(s):  
Penetration Depth ◽  
Cross Sections ◽  
Glass Ceramic ◽  
Testing Machine ◽  
Layered Structures ◽  
Micro Hardness ◽  
Hardness Tester ◽  
Cad Cam ◽  
The Impact

The aim of the study is to identify the endurance parameters of prosthetic crowns veneered with dedicated ceramics on metal, glass-ceramic, and ceramic frameworks. Metal frameworks were made using CAD/CAM milling technology and SLM technology, while the glass-ceramic and ceramic frameworks were produced using only the CAD/CAM milling technology. The research materials are samples replicating the layered structures of prosthetic crowns. The veneering procedure must ensure the adhesion of the ceramics to the loadbearing framework. The tests modelling the conditions of concentrated loads during chewing were carried out using the Instron 3345 testing machine. Determination of microhardness in cross-sections through layered structures of crowns was performed using the HMV Micro Hardness Tester. The comparison of force loading the indenter as a function of penetration depth indicates that the value of the maximum depth depends on the configuration of microhardness of the framework and dentine. The zirconium ceramics ZrO2 (3Y-TZP) – veneered with Elephant Sakura silica ceramics – should be indicated as the most advantageous material composition.

scholarly journals Four-body treatment of the K-shell positronium formation from multi-electron atoms

Open Physics ◽  
2014 ◽  
Vol 12 (3) ◽  
Author(s):  
Ebrahim Ghanbari-Adivi ◽  
Azime Velayati
Keyword(s):  
Cross Sections ◽  
Bound States ◽  
Transition Amplitude ◽  
Wave Functions ◽  
Positronium Formation ◽  
Distorted Wave ◽  
Helium Atoms ◽  
Three Body ◽  
Impact Energies ◽  
Correct Boundary Conditions

AbstractThe four-body Coulomb-Born distorted-wave approximation with correct boundary conditions (CBDW-4B) is applied to the K-shell positronium formation from multi-electron atoms at intermediate and high impact energies. In the present approach, both K-shell electrons are treated as active electrons. For collisions of positrons with helium, carbon, and neon atoms, both the post and prior forms of the transition amplitude are calculated and the corresponding differential and integral cross sections are compared with the results of the three-body version of the formalism (CBDW-3B). In order to investigate the effects of the static electronic correlations on the process, initial bound states of the active electrons in helium atoms are described by Hylleraas and Silverman wave functions. Also for positronium formation from helium atoms the obtained cross sections are compared with the available experimental data and also with the results of the other theories.

scholarly journals Full \(\mathcal{O}(\alpha)\) Electroweak Radiative Corrections to \(e^-e^+ \rightarrow W^-W^+\) with Initial Beam Polarization Effects

2020 ◽  
Vol 30 (2) ◽  
pp. 171
Author(s):  
Hong Khiem Phan ◽  
Anh Thu Nguyen ◽  
Huu Nghia Nguyen
Keyword(s):  
Cross Sections ◽  
Beam Polarization ◽  
Radiative Corrections ◽  
Initial State ◽  
Polarization Effects ◽  
Initial Beam ◽  
Electroweak Radiative Corrections ◽  
State Radiation ◽  
Lepton Colliders ◽  
The Impact

We calculate full \(\mathcal{O}(\alpha)\) electroweak radiative corrections and \(\mathcal{O}(\alpha^3)\) initial state radiation (ISR) corrections to \(e^-e^+ \rightarrow W^-W^+\) with initial beam polarization effects. In phenomenological results, we study the impact of electroweak and ISR corrections on cross-sections as well as their relevant distributions. We find that the corrections are order of 10% contributions. They are sizable contributions and should be taken into account at future lepton colliders.

scholarly journals Determination of Reinforced Concrete Rectangular Sections Having Plastic Moments Equal to all IPE Profiles

2021 ◽  
Vol 7 (4) ◽  
pp. 614-632
Author(s):  
Sayeh Beroual ◽  
Mohamed Laid Samai
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Cross Sections ◽  
Steel Structures ◽  
Structural Elements ◽  
Great Precision ◽  
Design Charts ◽  
Eurocode 2 ◽  
The Impact

The comparison between steel structures and reinforced concrete structures has always been governed by economy and response to earthquake. Steel structures being lighter and are thus more efficient to resist earthquake. On the other hand, they are more expensive (4 to 5 times). Theoretically, two structural elements having the same plastic moment have an equal failure or collapse load. Different profiles of IPE are realized in industry and all their characteristics are determined with a great precision (weight, geometrical characteristics and thus their plastic moment). Determining equivalent rectangular singly reinforced concrete cross-sections is not easy and seems impossible to be solved analytically. To a given profile it may be found a multitude of equivalent rectangular reinforced concrete cross-section (singly and doubly reinforced with different yield strengths and compositions of concrete). To take into consideration all these factors, it is absolutely necessary to construct three axis design charts with an appropriate choice of system of coordinates in order to cover all possible ranges of different parameters. The choice of all these possible rectangular reinforced concrete sections is governed by the plastic performance of these later. They must be under reinforced, allowing plastification of steel before failure in order to permit the redistribution phenomenon in plastic analysis. The exploitation of these different charts has revealed that the absolute majority of these rectangular reinforced concrete cross-section are reasonably well designed and are in conformity with the dimensions used in practice. The results of the present characterization using Eurocode 2 characteristics are compared to those of CP110. The impact does not seem to be very relevant. Doi: 10.28991/cej-2021-03091677 Full Text: PDF

scholarly journals DETERMINATION OF THE ELEMENTS SIGNIFICANCE IN THE RELIABILITY OF REDUNDANT FRAMES

2019 ◽  
Vol 15 (3) ◽  
pp. 109-119
Author(s):  
Sergii Pichugin ◽  
Viktor Chichulin ◽  
Ksenia Chichulina
Keyword(s):  
Cross Sections ◽  
Limit Equilibrium ◽  
Probabilistic Method ◽  
Steel Structures ◽  
Longitudinal Force ◽  
Software Systems ◽  
Method Of Calculation ◽  
The Individual ◽  
The Impact

The paper attacks the problem of steel redundant structures reliability. In calculations the probabilistic method of limit equilibrium is applied. All possible mechanisms of structural failure are considered. The influence of each section on the work of the frame as a whole is taken into account. Stochastic strength and load characteristics are used in the calculations. The proposed method of calculation allows to obtain structures with a given reliability. The calculation provides an opportunity to take into account the existing reserves of frames. The numerical example uses the logic of probabilistic transformations. The graphs of specific contributions of individual sections and the most probable mechanisms of destruction are presented. The probabilistic method takes into account the correlation between the individual mechanisms of destruction. The developed method determines the limiting moments, but it is allowed to take into account the action of the longitudinal force. In this example, the task was to align the impact of the frame sections without reducing the specified reliability, but it is possible to obtain a design with the same specific contributions, which is most economically justified. Specific contributions are increased or decreased as necessary to obtain a design with equal probability of failure. In the design, the influence of destruction individual mechanisms is used, because the cross sections of the beam span or floor column do not change from the design conditions. The method provides an opportunity to obtain more optimal designs and the use of modern software systems for static calculation. Recommendations for the design of these structures have been developed. It is proposed to use the reliability coefficient of redundant steel structures.

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