Using a Current Shunt for the Purpose of High-Current Pulse Measurement

Measurement of high-current pulses is crucial in some special applications, e.g., electrodynamic accelerators (EA) and converters. In such cases, the current shunts have limitations concerning the frequency bandwidth. To overcome the problem, a method based on the shunt mathematical model is proposed. In the method, the solution of ordinary differential equations for the RL circuit is carried out in order to obtain the real current shape. To check the method, as a referee, a Rogowski coil dedicated to measuring high-current pulses was used. Additionally, the measurement results were compared with the mathematical model of the tested power supply system. Measurements were made for the short power supply circuit, which allows eliminating the nonlinearity. The calculations were carried out using a circuit model. In order to obtain the parameters of the shunt (resistance and inductance), it was modeled using an ANSYS/Q3D Extractor software. Comparison of calculation and measurement results confirms the correctness of our method. In order to compare results, the normalized root mean square error (NRMSE) was used.

Effect of joint rigidity on structural behavior of RC buildings

Non-linear static analysis or pushover analysis is now-a –days generally preferred by many researchers to analyse the non-linear behaviour of the structure. Present study includes the effect of joint rigidity on the behaviour of the structure. A building is modeled with 5 and 10 story and designed for gravity and earthquake resistant loads by considering joint rigidity factor as 0 and 1. The analysis is done in both X and Y directions by using pushover analysis in SAP2000 software. Comparison is made between then capacity curves obtained from designed models of rigidity and non-rigidity models. From the results it is concluded that structure designed using joint rigidity has more strength when compared non-rigid joints.

Analysis of enterprises with innovation activity with emphasis on enterprise size

Research background: Small and medium-sized enterprises (SMEs) play a crucial role in European economic. They are very important for the stability of national economy and for development of innovation. SMEs significantly contribute to innovation because they are under permanent pressure of competitors at the market. On the other hand, innovation in SMEs is hampered by many factors, such as lack of finance, lack of personnel, no experiences, insufficient public policy, etc. Purpose of the article: The main goal of the article is examining the impact of business size on innovation activity and thus confirm the irreplaceable importance of SMEs in the innovation ecosystem, compare innovation activity of Slovak SMEs with EU average. Methods: Several methods were used to achieve the goals. Demonstrating the close relationship between innovation and SMEs is realized through VOSviewer software. Comparison of innovation activity of Slovak SMEs with European Union average is realized through an in-depth analysis of selected indicators of Summary Innovation Index. Findings & Value added: SMEs are indeed the creator of innovation. Based on the results of bibliometric analysis, this fact can be confirmed. The innovation activity of SMEs in the Slovak Republic is below the EU average. This fact is caused by several limitation and problems that SMEs in the Slovakia have to face.

Determining LoA between Left Ventricular EF estimated from Abarquez Formula and Left Ventricular EF measured by 2D Echo

Background: The Abarquez formula (aVR QRS amplitude x 2.264) + (age x 0.645) has been offered to provide an estimate for LVEF measured by 2D Echo. However, studies aiming to establish agreement between the Abarquez formula and LVEF measured by 2D Echo are lacking. Aims and Objectives: The aim of this study was to compare the LVEF estimated from 12-lead ECG using the Abarquez formula with the LVEF measured using the 2DED in the following subpopulations: 18-35 years old, 36-60 years old, >60 years old, male, and female patients. To compare these two measurements, the limits of agreement (LoA) by Altman and Bland was used. Materials and Methods: Adult patients admitted in the VLMC from January to May 2019 with both a 12-lead ECG and a 2D Echo were included in the study. LVEF from 2D Echo and LVEF estimated using the Abarquez formula were recorded. Comparison of the two measurements was performed by Altman and Bland method using LoA at 95% confidence interval. This analysis was done using Analyse-It Software. Comparison of the mean differences between the two measurement methods was also done using STATA. Results: LVEF estimate using the Abarquez formula was found to significantly differ from LVEF measured using 2D Echo. Conclusions: The Abarquez formula cannot be used as a surrogate for LVEF measure by 2D Echo.

Fatigue Benchmark Comparison Effort Between Code_Aster and CNNC/NPIC Software: Part 2

Fatigue is identified as a significant degradation mode that affects nuclear power plants world-wide. Recent research on the interaction between fatigue degradation and the influence of PWR environment has caused international concern and triggered numerous research programs [1]. In this context, several codes & standards, including the RCC-M code, have included some technical mandatory or non-mandatory sections to address the issue. In RCC-M, this is compiled in the Rules in Probation Phase 2 and 3 [2]. Due to the novelty of these rules, there is room for improvement for the specific and practical implementation of these rules. AFCEN has hence launched a benchmark exercise at the end of 2019 to help increase the quality of these rules. Part 1 of this paper [3] states that EDF and CNNC/NPIC have launched an effort to benchmark their respective codes on fatigue calculation including the EAF algorithm. In the second part of the benchmark, the two companies started the code comparison based on a benchmark case provided by AFCEN. As stated previously, the 2016 edition of RCC-M code integrates the modifications made to the Code in Probation Phase 2 and 3(RPP)[2], which respectively modify the fatigue design curve for austenitic stainless steels and Nickel base alloys, as well as integrate environmental effects in the fatigue evaluation for austenitic stainless steel components. In this paper, a comparison between RCC-M RPP and NUREG/CR-6909 rev.1 [3] is proposed. The comparison focuses on the technical details of the strain rate calculation and transient combination method. The cumulative fatigue usage factor with or without considering EAF according to RCC-M RPP – 2 and RPP – 3 is given by EDF, using code_aster and its POST_RCCM operator. CNNC/NPIC will provide multiple sets of results including cumulative fatigue usage factors according to RCC-M RPP and NUREG CR/6909 rev. 1 respectively using its own software. Comparison of selection for peak and valleys points, Sn and Fen values are also presented. Differences of the algorithms of the two codes are also discussed.

Effect of Variable Tube Wall Thicknesses of Al-Mg-Si Alloy Tube During Electromagnetic Compression using Four Turn Axi-Symmetric Coil

Electromagnetic compression (EMC) is a solid state, high velocity process of deformation of materials. In this process the enhancement of the formability is achieved due to high strain rate forming. In the present study Aluminum alloy AA6061 tube has been compressed using four turn axisymmetric coil. The effect of variable tube wall thicknesses i.e. 1.0, 1.7, and 2.4 mm during the compression of the Al-Mg-Si Aluminum alloy tube electromagnetically has been studied. A constant gap between coil inner diameter (ID) and workpiece outer diameter (OD) was maintained. It has been found that the tube deformation was maximum when the wall thickness was minimum. For compression, 8 kJ energy was used with double power bank. A three dimensional (3D) model of four turn compression coil has been proposed using LS-DYNA software. Comparison between the numerical simulation and experimental results showed a close agreement between both the results. Compression using EMF process can be used in modern industries like automotive, aerospace and nuclear power plants.