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Dynamics of the External Environment (Market) and Strategic Behavior of the Construction Firm

Abstract

The dynamic changes in the external (and often inside) environment place every firm in front of serious new and unknown challenges and make it more difficult to adapt to them. Under these conditions known traditional short-term models of corporate behavior have an increasingly limited role and a chance for success. The main problem and goal of the company should be a clearly defined long-term strategy that allows building competitive advantages and performance. Therefore, the purpose of the study is to analyze the impact of a dynamic external environment (market) on strategic behavior by developing a conceptual model: “Dynamics of the external environment (market) - Strategic behavior - Competitive advantages” to be applied and tested in the activity of the construction firm.

Open access
Economical Valuation of Wave Power Plant in the Baltic Sea Region at Pre-Flexibility Stage

Abstract

The article deals with free surface gravity waves as one of the alternative energy sources and their use. The potential of the waves and their transformation devices are considered as the main energy use impact factors. The goal of the research is to perform a cost-benefit assessment. The following tasks have been set: to make an assessment of wave potential, to identify the conversion model and turbine, to determine economic criteria taking into account wave and price variability. The article also provides the description of the theoretical valuation of the costs of the mentioned turbine power plant.

Open access
Editors’ Note
Open access
Effect of Number and Position of Rotational Friction Dampers on Seismic Response of Steel Frame

Abstract

This paper deals with effect of number and position of friction dampers on seismic response of 2D steel frame. For the present study four structures with six storeys are subjected to a time history analysis. For each story are using two, four and six friction dampers with different positions keeping slip load and stiffness constant. To study the effect of number and position of dampers in structures, are analysed the time period, top roof displacement, maximum base shear and percentage energy dissipated in accordance with energy induced in the frame. The results indicate that number and placement of damper affects the structural response. A large number of dampers do not always lead to best benefit in terms of energy dissipation.

Open access
Effectiveness of Geant4 in Monte Carlo Simulation Studyofphonon Conduction in Sn Host with Si Nanowire Interface

Abstract

We have explored the effectiveness of Geant4 by using it to simulate phonon conduction in Sn Host with Si Nanowire Interface. Our Monte Carlo Simulation shows that the effectiveness of the phonon conduction Geant4 simulation increases when the system attained a steady state of 100 time steps. We have simulated phonon conduction in Sn host with Si nanowire interface using a Geant4Condensed Matter Physics Monte Carlo simulation toolkit in a low cost and less powerful processing computer machine. In the simulation, phonons were displaced inside a computation domain from their initial positions with the velocities and direction vectors assigned to them. A time step was selected so that a phonon can move at most the length of one sub-cell in one time step. Our phonon conduction analysis of SiSn based alloy using Geant4 showed performance enhancement and reasonable predicted thermal values. Numerical predictions of the thermal profile simulations of the values of the temperature in each cell were all within ten percent of the average temperature of Silicon – Tin.

Open access
The effects of fuel type on control rod reactivity of pebble-bed reactor

Abstract

As a crucial core physics parameter, the control rod reactivity has to be predicted for the control and safety of the reactor. This paper studies the control rod reactivity calculation of the pebble-bed reactor with three scenarios of UO2, (Th,U)O2, and PuO2 fuel type without any modifications in the configuration of the reactor core. The reactor geometry of HTR-10 was selected for the reactor model. The entire calculation of control rod reactivity was done using the MCNP6 code with ENDF/B-VII library. The calculation results show that the total reactivity worth of control rods in UO2-, (U,Th)O2-, and PuO2-fueled cores is 15.87, 15.25, and 14.33%Δk/k, respectively. These results prove that the effectiveness of total control rod in thorium and uranium cores is almost similar to but higher than that in plutonium cores. The highest reactivity worth of individual control rod in uranium, thorium and plutonium cores is 1.64, 1.44, and 1.53%Δk/k corresponding to CR8, CR1, and CR5, respectively. The other results demonstrate that the reactor can be safely shutdown with the control rods combination of CR3+CR5+CR8+CR10, CR2+CR3+CR7+CR8, and CR1+CR3+CR6+CR8 in UO2-, (U,Th)O2-, and PuO2-fueled cores, respectively. It can be concluded that, even though the calculation results are not so much different, however, the selection of control rods should be considered in the pebble-bed core design with different scenarios of fuel type.

Open access
Electronic and Thermoelectric Properties in Li-Based Half-Heusler Compounds: A First Principle Study

Abstract

In this paper, we performed a first principle study for new half-Heusler LiSrX(X= N, P, and As) working with WIEN2k code in the frame work of the density functional theory, and the Boltzmann theory. We estimated the exchange-correlation potential by the generalized gradient approximation (GGA). Energetically, the three compounds show a high stability in structure type2, we notice that the lattice constant increased while bulk modulus decreased in replacing the ions of size increasing. Based on our calculations, LiSrN, LiSrP, and LiSrAs compounds are mechanically stable, and show semiconductor nature with indirect band gaps of 1.21, 1.75 for LiSrN and LiSrAs, and direct band gap of 1.94 eV for LiSrP. The thermoelectric properties are calculated for LiSrX (X=N, P, and As) and they found a high power factor for the p-type doping concentration.

Open access
Ensuring Reliability of Control Data in Engineering Systems

Abstract

The paper presents the approach of determination of rationality coefficients of control system, inputted uncertainty, control of the process, system errors, and uncertainty. Algorithms for identifying the states of system have been developed on the basis of theorems of identification. They actually implement the theoretical multiplication cross-section and establish that increasing the reliability of information is possible only through the use of redundancy (structural, procedural, and informational). The increase in the reliability of control data with the developed methods ensures significant improvement of the functioning of information systems and facilitates the adoption of more substantiated decision making.

Open access
EPID – a useful interfraction QC tool

Abstract

Biomedical accelerators used in radiotherapy are equipped with detector arrays which are commonly used to obtain the image of patient position during the treatment session. These devices use both kilovolt and megavolt x-ray beams. The advantage of EPID (Electronic Portal Imaging Device) megavolt panels is the correlation of the measured signal with the calibrated dose. The EPID gives a possibility to verify delivered dose. The aim of the study is to answer the question whether EPID can be useful as a tool for interfraction QC (quality control) of dose and geometry repeatability.

The EPID system has been calibrated according to the manufacturer’s recommendations to obtain a signal and dose values correlation. Initially, the uncertainty of the EPID matrix measurement was estimated. According to that, the detecting sensitivity of two parameters was checked: discrepancies between the planned and measured dose and field geometry variance. Moreover, the linearity of measured signal-dose function was evaluated.

In the second part of the work, an analysis of several dose distributions was performed. In this study, the analysis of clinical cases was limited to stereotactic dynamic radiotherapy. Fluence maps were obtained as a result of the dose distribution measurements with the EPID during treatment sessions. The compatibility of fluence maps was analyzed using the gamma index. The fluence map acquired during the first fraction was the reference one. The obtained results show that EPID system can be used for interfraction control of dose and geometry repeatability.

Open access