Assessment of WWER-1000 Core Baffle Form Alteration during Operation

The paper illustrates the results of the computer assessment of the form alteration in WWER-1000 core baffle obtained via the solution to the coupled thermoelastoplastic task considering the strains of irradiation growth and creep. In the modeling of the contact conditions, the temperature redistribution is considered due to the incompliance of the coolant flow in the contact zone between the core baffle and in-vessel core barrel with the design conditions. The modern approaches to the modeling of strains of the irradiation growth and irradiation creep in austenite steels are used in the space-limited environment under neutron exposure and elevated temperature. The finite element analysis involves the mixed scheme of the finite element method, which allows determination of the stress-strain state with high accuracy. The calculations are performed in the two-dimensional statement for the cross-section of the core baffle with the maximum damaging dose and irradiation temperature under the condition of the generalized plane strain. The results of the calculations are presented for full-scale reactor operation and scheduled shutdown to recharge the fuel cluster at the end of core life. The data on the distribution and value of the gap between the core baffle and barrel, as well as the spacer grids of the edge fuel assemblies and reactor core baffle edges, have been obtained from the median values of the dose dependence on swelling at different temperatures in Kh18N10T austenite steel.

Equal-Order Polygonal Analysis for Fluid Computation in Curved Domain

Our research introduces a novel advanced method for fluid computation in complicated domain. It makes use of an advanced polygonal finite element applying equal-order scheme; within each element. Both velocity and pressure fields are represented by a polygonal basis shape function system. This technique is based on a combination of the equal-order mixed scheme method, the polygon finite element method (PFEM) and the adapted local projection method that is used to stabilize the pressure. In order to simulate the fluid flow, MATLAB is utilized for coding and programming. A numerical example of an incompressible fluid flow governed by Stokes system in curved domain is performed to demonstrate the applicability of our developed polygon element. Besides, through the numerical analysis, we show the high flexibility of PFEM for curved domains.

Environmental Implications of Taiwanese Oolong Tea and the Opportunities of Impact Reduction

Tea is the second most consumed beverage globally, yet its environmental implications are largely unknown. To overcome this knowledge gap, life-cycle analysis was conducted aiming to quantify the environmental impacts associated with tea production and consumption. To achieve this objective, Oolong tea production in Taiwan was selected to investigate the life-cycle impact in global warming potential (GWP) and eutrophication potential (EP) associated with one serving of hot tea consumed in Taiwan domestically and the international market in the U.S. and U.K. The results indicate that each serving of Oolong tea can result in a total of 28.6 g CO2-equivalent of GWP and 0.09 g N-equivalent of EP. Over 52% of GWP and 44% of EP are associated with the tea’s cultivation, in which the application and production of agrochemicals accounts for 90% of GWP and 98% of EP. International consumption can increase GWP and EP by 19% and 26%, respectively, which is largely attributable to the change of cooking energy from natural gases to an electric-gas mixed scheme. The findings from this study articulate the environmental portfolio of Oolong tea. More importantly, we can identify opportunities to mitigate the environmental footprint of Oolong tea in order to advance future sustainability.

A priori error estimates for a discretized poro-elastic–elastic system solved by a fixed-stress algorithm

We consider a poro-elastic region embedded into an elastic non-porous region. The elastic displacement equations are discretized by a continuous Galerkin scheme, while the flow equations for the pressure in the poro-elastic medium are discretized by either a continuous Galerkin scheme or a mixed scheme. Since the overall system of equations is very large, a fixed-stress algorithm is used at each time step to decouple the displacement from the flow equations in the poro-elastic region. We prove a priori error estimates for the resulting Galerkin scheme as well as the mixed scheme, with the expected order of accuracy, provided the algorithm is sufficiently iterated at each time step. These theoretical results are confirmed by a numerical experiment performed with the mixed scheme. A complete analysis including a posteriori estimates for both the Galerkin and the mixed scheme has been done but is too long to appear here.

TECHNOLOGY OF UNIQUE BUILDINGS’ CONSTRUCTION IN THE CONSTRAINED CONDITIONS OF OPERATING ENTERPRISE

Introduction.There is a need for detailed consideration of technological solutions of the constructed object while the process of the work projects’ development (WPD). The features of WPD development are considered on the basis of the flare tower as a part of the flare installation of the oil refining enterprise. The problems of organizational and technological design (development of WPD) for such facilities’ type should be solved many times due to the fact that there is a modernization of oil refining enterprises in the country. Moreover, the obtained results of calculations allow conducting more rational technological solutions for the construction of the flare tower and such solutions affect the period of the flare installation.Materials and methods.The technology of the flare tower construction as a part of the flare installation is quite complex due to the features of the unique structure and cramped construction site. Accordingly, the choice of technology for the flare tower construction is made by using the features of its design solution and by the detailed consideration of options for installation mechanization. The options are evaluated by using an economic criterion (reduced cost). The calculations are based on modern installation cranes recommended for usage on this type of unique structures.Results.As a result of technical and economic calculations of the flare tower construction technology, the method of its construction is chosen due to the rational version of installation mechanization. The paper presents the calculations’ results of the given costs and the technical characteristics of the cranes. In addition, the technology of the flare tower installation is organized with the method of the tower blocks assembly.Discussion and conclusions.As could be seen, the construction technology by the mixed scheme on the chosen option is developed by the authors.

The Efficiency of OLS Estimators of Structural Parameters in a Simple Linear Regression Model in the Calibration of the Averages Scheme

A simple linear regression model is one of the pillars of classic econometrics. Multiple areas of research function within its scope. One of the many fundamental questions in the model concerns proving the efficiency of the most commonly used OLS estimators and examining their properties. In the literature of the subject one can find taking back to this scope and certain solutions in that regard. Methodically, they are borrowed from the multiple regression model or also from a boundary partial model. Not everything, however, is here complete and consistent. In the paper a completely new scheme is proposed, based on the implementation of the Cauchy-Schwarz inequality in the arrangement of the constraint aggregated from calibrated appropriately secondary constraints of unbiasedness which in a result of choice the appropriate calibrator for each variable directly leads to showing this property. A separate range-is a matter of choice of such a calibrator. These deliberations, on account of the volume and kinds of the calibration, were divided into a few parts. In the one the efficiency of OLS estimators is proven in a mixed scheme of the calibration by averages, that is preliminary, and in the most basic frames of the proposed methodology. In these frames the future outlines and general premises constituting the base of more distant generalizations are being created.