Solitons for the (2+1)-dimensional Boiti–Leon–Manna–Pempinelli equation for an irrotational incompressible fluid via the Pfaffian technique

2019 ◽  
Vol 33 (30) ◽  
pp. 1950376 ◽  
Author(s):  
Lei Hu ◽  
Yi-Tian Gao ◽  
Shu-Liang Jia ◽  
Jing-Jing Su ◽  
Gao-Fu Deng
Keyword(s):  
Incompressible Fluid ◽  
Stream Function ◽  
Incompressible Flow ◽  
Soliton Solutions ◽  
Auxiliary Function ◽  
Auxiliary Parameter ◽  
The Real ◽  
Before And After ◽  
Space Coordinate

Fluids are common in nature, the study of which helps the design of the related industries. Under investigation in this letter is the (2[Formula: see text]+[Formula: see text]1)-dimensional Boiti–Leon–Manna–Pempinelli equation for an irrotational incompressible fluid. Pfaffian solutions have been obtained based on the Pfaffian technique with the assistance of the real auxiliary function [Formula: see text]. N-soliton solutions with [Formula: see text] are constructed, where y is the scaled space coordinate and [Formula: see text] is the steady stream function in the irrotational incompressible flow. Background shapes of the solutions are affected by [Formula: see text], but the structures of the solutions are affected by the derivative of the log terms in the solutions. Neighborhoods at the origins of the solitons are different in consequence of the different values of the real auxiliary parameter a. One- and two-soliton solutions are illustrated, which are the superpositions of the two kink solitons and different forms of [Formula: see text]. Interactions of the two solitons are presented, from which we see that the velocities, amplitudes and shapes of the two solitons remain unchanged before and after each interaction.

Real-life Field Studies of the NOx Removing Properties of Photocatalytic Surfaces in Roskilde and Copenhagen Airport, Denmark

2020 ◽  
Vol 01 ◽  
Author(s):  
Henrik Jensen ◽  
Pernille D. Pedersen
Keyword(s):  
Air Quality ◽  
High Stability ◽  
Reference Site ◽  
Real Life ◽  
Field Studies ◽  
The Real ◽  
Before And After ◽  
Parking Lot ◽  
Photocatalytic Concrete

Aims: To evaluate the real-life effect of photocatalytic surfaces on the air quality at two test-sites in Denmark. Background: Poor air quality is today one of the largest environmental issues, due to the adverse effects on human health associated with high levels of air pollution, including respiratory issues, cardiovascular disease (CVD), and lung cancer. NOx removal by TiO2 based photocatalysis is a tool to improve air quality locally in areas where people are exposed. Methods: Two test sites were constructed in Roskilde and Copenhage airport. In Roskilde, the existing asphalt at two parking lots was treated with TiO2 containing liquid and an in-situ ISO 22197-1 test setup was developed to enable in-situ evaluation of the activity of the asphalt. In CPH airport, photocatalytic concrete tiles were installed at the "kiss and fly" parking lot, and NOx levels were continuously monitored in 0.5 m by CLD at the active site and a comparable reference site before and after installation for a period of 2 years. Results: The Roskilde showed high stability of the photocatalytic coating with the activity being largely unchanged over a period of 2 years. The CPH airport study showed that the average NOx levels were decreased by 12 % comparing the before and after NOx concentrations at the active and reference site. Conclusion: The joined results of the two Danish demonstration projects illustrate a high stability of the photocatalytic coating as well as a high potential for improvements of the real-life air quality in polluted areas.

Contact Width Analysis of Corrugated Metal Gasket Based on Surface Roughness

2013 ◽  
Vol 856 ◽  
pp. 92-97 ◽  
Author(s):  
Shigeyuki Haruyama ◽  
Didik Nurhadiyanto ◽  
Ken Kaminishi
Keyword(s):  
Surface Roughness ◽  
The Real ◽  
Real Contact ◽  
Contact Width ◽  
Before And After ◽  
Optimizing Design ◽  
Roughness Evaluation ◽  
Helium Leakage ◽  
Corrugated Metal ◽  
Important Design

Contact width is important design parameter for optimizing design of new metal gasket. The contact width was found have relationship with helium leak quantity. Increasing axial force, the contact width will increase and helium leakage will decrease. This study we conducted the surface roughness evaluation of 25A-size metal gasket before and after use. The results denote the real contact width after contact with flange having different surface roughness. The real contact width for the flange having smoother surface roughness is wider than the rougher one.

Impact of Canada's Pacific Salmon Fleet Control Program

1979 ◽  
Vol 36 (7) ◽  
pp. 764-769 ◽  
Author(s):  
Peter H. Pearse ◽  
James E. Wilen
Keyword(s):  
Key Words ◽  
Statistical Data ◽  
Pacific Salmon ◽  
Control Program ◽  
Resource Rent ◽  
The Real ◽  
Before And After ◽  
Salmon Fishery

The available statistical data are analyzed to appraise the success of Canada's Pacific salmon fleet rationalization program, in terms of the extent to which it has prevented fishing costs from rising in pace with the value of the catch. It is found that while the fleet's revenues increased at about the same rate before and after the scheme was introduced in 1969, the real capital employed increased more slowly under the controls than earlier. The program has, nevertheless, failed in its purpose of preventing further expansion of redundant capital in the fleet. The reasons for this failure, and for certain apparent shifts in the structure of the fleet, are discussed. Key words: Pacific salmon fishery, capitalization, economic rationalization, resource rent

scholarly journals On the Stream Function-Vorticity Finite Element Formulation for Incompressible Flow in Porous Media

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Abdellatif Agouzal ◽  
Karam Allali ◽  
Siham Binna
Keyword(s):  
Finite Element ◽  
Porous Media ◽  
Stream Function ◽  
Incompressible Flow ◽  
Equations Of Motion ◽  
Finite Element Formulation ◽  
Flow In Porous Media ◽  
Darcy Law ◽  
Element Formulation ◽  
Discrete Problem

Stream function-vorticity finite element formulation for incompressible flow in porous media is presented. The model consists of the heat equation, the equation for the concentration, and the equations of motion under the Darcy law. The existence of solution for the discrete problem is established. Optimal a priori error estimates are given.

Abstract 20233: Does Evidence Influence Practice in the Real World? Secular Trends in Indication for PCI and Use of Drug-Eluting vs. Bare-Metal Stents From 2006-2012

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Elizabeth B Pathak ◽  
Jason L Salemi ◽  
Amit P Pathak
Keyword(s):  
Real World ◽  
Bare Metal Stents ◽  
Metal Stents ◽  
Bare Metal ◽  
Discharge Data ◽  
The Real ◽  
Primary Indication ◽  
Stable Coronary Heart Disease ◽  
Before And After ◽  
Drug Eluting

Introduction: In this study, we examined the real-world impact of research evidence on the use of and indications for percutaneous coronary intervention (PCI) (before and after COURAGE Trial publication) and the choice of drug eluting stents (DES) vs. bare metal stents (BMS) (before and after FDA warnings about risk of DES thrombosis). Methods: We used hospital discharge data from Florida to calculate the distribution of primary indication for PCI and the % of PCI patients who received DES, BMS, or no stent on a quarterly basis from Jan 2006 - Jun 2012. We plotted stent trends separately for patients with principal diagnosis of STEMI (n=66,054), NSTEMI/ICS (n=140,886), and stable CHD (n=117,307). Results: Since 2006, the % of PCIs with a primary indication of either STEMI or NSTEMI has steadily increased, while the % with an indication of stable CHD declined from 45% to 28%. In early 2006, DES were used in 86.9% of NSTEMI patients, 87.5% of stable CHD patients, and 81.4% of STEMI patients. DES use first declined in all diagnosis groups in Q3 2006, coinciding with the release of meta-analysis results showing higher risk of late stent thrombosis for DES vs. BMS. The lowest rate of DES usage was reached in Q1 2008 (45% for STEMI, 63% for NSTEMI, 67% for stable CHD). However, by Q2 2012, DES use had increased to 60% in STEMI cases, 75% in NSTEMI cases, and 76% in stable CHD cases. The percent of PCI patients who received no stent has remained stable at < 9% since 2006, regardless of diagnosis. Conclusions: The COURAGE Trial showed no benefit of PCI over medical treatment in stable coronary heart disease (CHD). From 2006-2012, the proportion of PCIs with an indication of stable CHD declined from 45% to 28%, indicating a real-world response to evidence. Similarly, following controversy about long-term effects of DES, off-label use, and patient compliance with thienopyridines which began in late 2006, there was an immediate resurgence in use of BMS, especially for STEMI. However, the proportion of patients receiving DES has steadily increased since early 2008, regardless of primary indication. More research on the influence of provider and hospital characteristics on response to evidence is needed.

Resonance Y-type soliton, hybrid and quasi-periodic wave solutions of a generalized (2+1)-dimensional nonlinear wave equation

2021 ◽  
Author(s):  
Lingchao He ◽  
Jianwen Zhang ◽  
Zhonglong Zhao
Keyword(s):  
Wave Equation ◽  
Nonlinear Wave ◽  
Nonlinear Wave Equation ◽  
Water Waves ◽  
Asymptotic Properties ◽  
Soliton Solutions ◽  
Periodic Wave ◽  
Periodic Wave Solutions ◽  
Wave Solutions ◽  
Before And After

Abstract In this paper, we consider a generalized (2+1)-dimensional nonlinear wave equation. Based on the bilinear, the N-soliton solutions are obtained. The resonance Y-type soliton and the interaction solutions between M-resonance Y-type solitons and P-resonance Y-type solitons are constructed by adding some new constraints to the parameters of the N-soliton solutions. The new type of two-opening resonance Y-type soliton solutions are presented by choosing some appropriate parameters in 3-soliton solutions. The hybrid solutions consisting of resonance Y-type solitons, breathers and lumps are investigated. The trajectories of the lump waves before and after the collision with the Y-type solitons are analyzed from the perspective of mathematical mechanism. Furthermore, the multi-dimensional Riemann-theta function is employed to investigate the quasi-periodic wave solutions. The one-periodic and two-periodic wave solutions are obtained. The asymptotic properties are systematically analyzed, which establish the relations between the quasi-periodic wave solutions and the soliton solutions. The results may be helpful to provide some effective information to analyze the dynamical behaviors of solitons, fluid mechanics, shallow water waves and optical solitons.

scholarly journals Particulate Matter and COVID-19 Disease Diffusion in Emilia-Romagna (Italy). Already a Cold Case?

Computation ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 59 ◽  
Author(s):  
Giovanni Delnevo ◽  
Silvia Mirri ◽  
Marco Roccetti
Keyword(s):  
Granger Causality ◽  
Air Pollutants ◽  
Climatic Factors ◽  
Virus Disease ◽  
Hypothesis Test ◽  
Statistical Hypothesis ◽  
Clear Correlation ◽  
The Real ◽  
Statistical Hypothesis Test ◽  
Before And After

As we prepare to emerge from an extensive and unprecedented lockdown period, due to the COVID-19 virus infection that hit the Northern regions of Italy with the Europe’s highest death toll, it becomes clear that what has gone wrong rests upon a combination of demographic, healthcare, political, business, organizational, and climatic factors that are out of our scientific scope. Nonetheless, looking at this problem from a patient’s perspective, it is indisputable that risk factors, considered as associated with the development of the virus disease, include older age, history of smoking, hypertension and heart disease. While several studies have already shown that many of these diseases can also be favored by a protracted exposure to air pollution, there has been recently an insurgence of negative commentary against authors who have correlated the fatal consequences of COVID-19 (also) to the exposition of specific air pollutants. Well aware that understanding the real connection between the spread of this fatal virus and air pollutants would require many other investigations at a level appropriate to the scale of this phenomenon (e.g., biological, chemical, and physical), we propose the results of a study, where a series of the measures of the daily values of PM2.5, PM10, and NO2 were considered over time, while the Granger causality statistical hypothesis test was used for determining the presence of a possible correlation with the series of the new daily COVID19 infections, in the period February–April 2020, in Emilia-Romagna. Results taken both before and after the governmental lockdown decisions show a clear correlation, although strictly seen from a Granger causality perspective. Moving beyond the relevance of our results towards the real extent of such a correlation, our scientific efforts aim at reinvigorating the debate on a relevant case, that should not remain unsolved or no longer investigated.

scholarly journals Naar Skyggen er ligest...

2001 ◽  
Vol 52 (1) ◽  
pp. 58-69
Author(s):  
Flemming Lundgreen-Nielsen
Keyword(s):  
Contemporary Literature ◽  
Small Contribution ◽  
The Sun ◽  
Real Thing ◽  
The Real ◽  
Unambiguous Determination ◽  
Before And After ◽  
The Republic ◽  
Natural Fact

»When the Shadow comes nearest..« By Flemming Lundgreen-NielsenThis small contribution deals with two intricate lines from stanza 5 of Grundtvig’s 1824 poem .The Land of the Living.. They are usually taken to mean that when likeness in the shape of shadows comes nearest the real thing, the little ones observing them weep, because in human poetry and arts which strive to reflect eternity similarity is not and can never be identity. Chr. Thodberg has repeatedly since 1971 suggested a different understanding of the lines to the effect that »ligest« (i.e. .most similar to.) may be interpreted as »most vertical«, referring to the shrinkage or entire disappearance of shadows at noon, when the sun reaches zenith. Thodberg departs from an off-hand commentary by Grundtvig about this natural fact in a sermon delivered on 27 March 1823. The author tries to demonstrate that Grundtvig's varying usage of theword shadow (»Skygge«) both before and after 1824 makes it impossible to arrive at an unambiguous determination regarding the word in the said lines. Furthermore, the superlative degree »ligest« meaning »most vertical« neither seems to have been recorded in the language of Grundtvig and his contemporaries nor in older periods.Contrarily, »ligest« meaning »most similar to« can be found in ancient Danish proverbs which Grundtvig studied extensively from 1816 and until he edited and published a collection of them in 1845, and it can also be located in contemporary literature. Returning from there to the meaning of shadow, the author by means of quotes from Grundtvig’s brief but precise historical evaluations of Plato and his philosophy (in 1812 and 1833) is inclined to support the traditional interpretation that the shadows making little ones weep originate in the famous cave metaphor in the fifth book of Plato’s dialogue The Republic. Finally, two other details deriving from Grundtvig’s studies of Danish proverbs in the Peder Syv edition (1688) are mentioned to throw light on a couple of nebulous expressions in two other lyrical poems by him.

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