scholarly journals Will a natural collective immunity of Ukrainians restrain new COVID-19 waves?

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Mathematical Modeling ◽  
Parameter Identification ◽  
Real Number ◽  
Sir Model ◽  
Natural Immunity ◽  
Identification Procedure ◽  
Optimal Value ◽  
The Difference

The visible and real sizes the COVID-19 epidemic in Ukraine were estimated with the use of the number of laboratory-confirmed cases (accumulated in May and June 2021), the generalized SIR-model and the parameter identification procedure taking into account the difference between registered and real number of cases. The calculated optimal value of the visibility coefficient shows that most Ukrainians have already been infected with the coronavirus, and some more than once, i.e., Ukrainians have probably achieved a natural collective immunity. Nevertheless, a large number of new strains and short-lived antibodies can cause new pandemic waves. In particular, the beginning of such a wave, we probably see in Ukraine in mid-July 2021. The further dynamics of the epidemic and its comparison with the results of mathematical modeling will be able to answer many important questions about the natural immunity and effectiveness of vaccines.

scholarly journals The COVID-19 pandemic storm in India subsides, but the calm is still far away

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Real Number ◽  
Sir Model ◽  
Final Size ◽  
The Difference ◽  
Pandemic Wave

In May 2021, the number of new COVID-19 patients in India began to decline, as predicted by the generalized SIR-model (susceptible-infected-removed). The calculations of the final size of this pandemic wave and its duration probably were too pessimistic. New SIR simulations with the use of fresher datasets are necessary in order to update the predictions and to calculate the difference between the registered (laboratory-confirmed) and real number of cases.

scholarly journals Final sizes and durations of new COVID-19 pandemic waves in Ukraine and around the world predicted by generalized SIR model

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Parameter Identification ◽  
Exponential Growth ◽  
Sir Model ◽  
Risk Of Infection ◽  
Identification Procedure ◽  
Epidemic Dynamics ◽  
The World

New waves of the COVID-19 pandemic in Ukraine, which began in the summer of 2021, and after holidays in the middle of October 2021, were characterized by almost exponential growth of smoothed daily numbers of new cases. This is a matter of great concern and the need to immediately predict the epidemic dynamics in order to assess the possible maximum values of new cases, the risk of infection and the number of deaths. The generalized SIR-model and corresponding parameter identification procedure was used to simulate and predict the dynamics of two new epidemic waves in Ukraine and one in the whole world. Results of calculations show that new cases in Ukraine will not stop to appear before November 2022. If the global situation with vaccination, testing and treatment will not change, the pandemic could continue for another ten years.

scholarly journals Visible and real dynamics of the COVID-19 pandemic in Ukraine in the spring of 2021

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Real Number ◽  
Sir Model ◽  
Real Numbers ◽  
The Real ◽  
Daily Number ◽  
Optimal Value ◽  
Theoretical Predictions ◽  
Epidemic Wave ◽  
Good Agreement

The visible and real sizes the last COVID-19 epidemic wave in Ukraine, estimated in March 2021 with the use of generalized SIR-model, are compared with number of cases registered in the spring of 2021. We have used the optimal value of the visibility coefficient in order to estimate the real numbers of accumulated cases, real daily numbers of new cases and real number of infectious persons. The results show that the latest prediction for Ukraine is in rather good agreement with observations, but the daily number of new cases decreases more slowly than theoretical predictions. The large real number of infectious people threatens the emergence of new strains of coronavirus and the beginning of new epidemic waves.

scholarly journals Final sizes and durations of new COVID-19 pandemic waves in Poland and Germany predicted by generalized SIR model

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Parameter Identification ◽  
Sir Model ◽  
Risk Of Infection ◽  
Identification Procedure ◽  
Epidemic Dynamics

New waves of the COVID-19 pandemic in Europe, which began in the autumn of 2021, are a matter of great concern and the need to immediately predict the epidemic dynamics in order to assess the possible maximum values of new cases, the risk of infection and the number of deaths. The generalized SIR-model and corresponding parameter identification procedure was used to simulate and predict the dynamics of new epidemic waves in Poland and Germany. Results of calculations show that new cases in these countries will not stop to appear in 2022.

scholarly journals Simulation and predictions of a new COVID-19 pandemic wave in Ukraine with the use of generalized SIR model

2021 ◽  
Author(s):  
Igor Nesteruk
Keyword(s):  
Parameter Identification ◽  
Exponential Growth ◽  
Sir Model ◽  
New Wave ◽  
Risk Of Infection ◽  
Identification Procedure ◽  
Pandemic Wave ◽  
Epidemic Wave

A new wave of the COVID-19 pandemic in Ukraine, which began in the summer of 2021, was characterized by almost exponential growth of smoothed daily numbers of new cases. This is a matter of great concern and the need to immediately predict the dynamics of the epidemic in order to assess the possible maximum values of new cases, the risk of infection and the number of deaths. The generalized SIR-model and corresponding parameter identification procedure was used to simulate and predict the dynamics of this epidemic wave. The new COVID-19 epidemic wave in Ukraine will begin to subside in mid-October 2021, but its duration will be quite long. Unfortunately, new cases may appear by the summer of 2022.

Effect of titanium alloys elasticity modulus on warping of stamped blanks during cooling

2021 ◽  
pp. 221-227
Author(s):  
M.O. Smirnov ◽  
A.M. Zolotov ◽  
A.M. Tyukhtyaev
Keyword(s):  
Mathematical Modeling ◽  
Titanium Alloys ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Elasticity Modulus ◽  
Preliminary Deformation ◽  
Wide Spread ◽  
Temperature Dependences ◽  
Cumulative Deformation ◽  
The Difference

Wide spread in the values of the elasticity modulus of the titanium VT6 alloy and its analogs Ti—6Al—4V, Ti—6Al—4V ELI at room temperature and at elevated temperatures is revealed аs result of the literature sources analysis. The data are ambiguous, the available temperature dependences of the elasticity modulus have very different values starting from the temperature T l 500 °C. Mathematical modeling of the warping process is carried out on the example of figurine-shaped stamped blank of turbine blade using various dependences of the elasticity modulus on temperature. Cases of warping during cooling of stamped blank after cooling-down in stamp with and without cumulative deformation are considered. The difference in the course of thermal deformations during the cooling of the workpiece is obtained using different temperature dependences of the elasticity modulus. The presence of preliminary deformation increases the warping of the workpieces.

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