Software Analytical Instrument for Assessment of the Process of Casting Slabs

Zden?k FRAN?K,FRANTI?EK KAVI?KA,JOSEF ?T?TINA,MILO? MASARIK 한국소성가공학회 2010 기타자료 Vol.2010 No.6

The paper describes the original proposal of ways of solution and function of the program equipment for assessment of the process of casting slabs. The program system LITIOS was developed and implemented in EVRAZ Vitkovice Steel Ostrava on the equipment of continuous casting of steel (further only ECC). This program system works on the data warehouse of technological parameters of casting and quality parameters of slabs. It enables an ECC technologist to analyze the course of casting melt and with using statistics methods to set the influence of single technological parameters on the duality of final slabs. The system also enables long term monitoring and optimization of the production.

Alternating Ring-Opening Copolymerization of Cyclohexene Oxide with Phthalic Anhydride Catalyzed by Iron(III) Salen Complexes

Robert Mundil,Jan Merna,Zdeněk Hošťálek,Ivana Šeděnková 한국고분자학회 2015 Macromolecular Research Vol.23 No.2

A series of three iron(III) salen complexes was synthesized and successfully used for copolymerizationof cyclohexene oxide and phthalic anhydride. Catalytic systems based on an iron(III) salen complex in combinationwith 4-(dimethylamino)pyridine (DMAP) or bis(triphenylphosphine)iminium chloride (PPNCl) cocatalysts producedpurely alternating copolymer with narrow molar mass distributions. [N,N'-Bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexylenediamine] iron(III) chloride was the most active complex and afforded the copolymer even in theabsence of the cocatalysts. Other iron complexes were completely inactive in absence of a cocatalyst. Both DMAPand PPNCl alone were able to catalyze the copolymerization, affording purely alternating copolymers in good yields.

Temperature of Connections During Fire on Steel Framed Building

Jiří Chlouba,František Wald,Zdeněk Sokol 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.1

To study the global structural and thermal behaviour of buildings in fire, a research project was conducted including a fullscale test on a three storey steel frame building at Mittal Steel Ostrava before demolition. The main goal of the experiment was to verify the method for predicting joint temperatures and to improve it for the cooling phase. The fire compartment extending over a floor area of 24 m2 was built on the second floor. The fire load was 140 kg/m2 of wood and the ventilation was limited to an opening of 1,400×1,970 mm. This paper presents the time-temperature curves showing the development of the fire in the compartment and in the primary and secondary beams and its header plate connections. Comparisons are made between the test results and the temperatures predicted by the structural Eurocodes. The sensitivity of the connection behaviour to the estimated temperatures and associated degradation in material properties during the fire is demonstrated. To study the global structural and thermal behaviour of buildings in fire, a research project was conducted including a fullscale test on a three storey steel frame building at Mittal Steel Ostrava before demolition. The main goal of the experiment was to verify the method for predicting joint temperatures and to improve it for the cooling phase. The fire compartment extending over a floor area of 24 m2 was built on the second floor. The fire load was 140 kg/m2 of wood and the ventilation was limited to an opening of 1,400×1,970 mm. This paper presents the time-temperature curves showing the development of the fire in the compartment and in the primary and secondary beams and its header plate connections. Comparisons are made between the test results and the temperatures predicted by the structural Eurocodes. The sensitivity of the connection behaviour to the estimated temperatures and associated degradation in material properties during the fire is demonstrated.

Reliability and risk treatment centered maintenance

Martin Pexa,Tomáš Hladík,Zdeněk Aleš,Václav Legát,Vít Havlů,Miroslav Müller,Petr Valášek 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.10

We propose a new methodology for application of well-known tools – RCM, RBI and SIFpro – with the aim to treat risks by means ofsuitable maintenance. The basis of the new methodology is the complex application of all three methods at the same time and not separatelyas is typical today. The proposed methodology suggests having just one managing team for reliability and risk treatment centredmaintenance (RRTCM), employing existing RCM, RBI, and SIFpro tools concurrently. This approach allows for significant reduction ofengineering activities’ duration. In the proposed methodology these activities are staged into five phases and structured to eliminate allduplication resulting from separate application of the three tools. The newly proposed methodology saves 45% to 50% of the engineeringworkload and adequate significant financial savings.

Calculation and measurement of Al prompt capture gammas above water in a pool-type reactor

Czakoj Tomáš,Košťál Michal,Losa Evžen,Matěj Zdeněk,Šimon Jan,Mravec Filip,Cvachovec František 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10

Prompt capture gammas are an important part of the fission reactor gamma field. Because some of the structural materials after neutron capture can emit photons with high energies forming the dominant component of the gamma spectrum in the high energy region, the following study of the high energy capture gamma was carried out. High energy gamma radiation may play a major role in areas of the radiation sciences as reactor dosimetry. The HPGe measurements and calculations of the high-energy aluminum capture gamma were performed at two moderator levels in the VR-1 pool-type reactor. The result comparison for nominal levels was within two sigma uncertainties for the major 7.724 MeV peak. A larger discrepancy of 60% was found for the 7.693 MeV peak. The spectra were also measured using a stilbene detector, and a good agreement between HPGe and stilbene was observed. This confirms the validity of stilbene measurements of gamma flux. Additionally, agreement of the wide peak measurement in 7e9.2 MeV by stilbene detector shows the possibility of using the organic scintillators as an independent power monitor. This fact is valid in these reactor types because power is proportional to the thermal neutron flux, which is also proportional to the production of capture gammas forming the wide peak

Impact of postoperative complications on clinical and economic consequences in pancreatic surgery

Filip Čečka,Bohumil Jon,Eva Čermáková,Zdeněk Šubrt,Alexander Ferko 대한외과학회 2016 Annals of Surgical Treatment and Research(ASRT) Vol.90 No.1

Purpose: Patients who develop complications consume a disproportionately large share of available resources in surgery; therefore the attention of healthcare funders focuses on the economic impact of complications. The main objective of this work was to assess the clinical and economic impact of postoperative complications in pancreatic surgery, and furthermore to assess risk factors for increased costs. Methods: In all, 161 consecutive patients underwent pancreatic resection. The costs of the treatment were determined and analyzed. Results: The overall morbidity rate was 53.4%, and the in-hospital mortality rate was 3.7%. The median of costs for all patients without complication was 3,963 Euro, whereas the median of costs for patients with at least one complication was significantly increased at 10,670 Euro (P < 0.001). In multivariate analysis American Society of Anesthesiologists ≥ 3 (P = 0.006), multivisceral resection (P < 0.001) and any complication (P < 0.001) were independently associated with increased costs. Conclusion: Postoperative complications are associated with an increase in mortality, length of hospital stay, and hospital costs. The treatment costs increase with the severity of the postoperative complications. Those factors that are known to increase the treatment costs in pancreatic resection should be considered when planning patients for surgery

Design of corrugated sheets exposed to fire

Zden k Sokol,František Wald,Petra Kallerová 국제구조공학회 2008 Steel and Composite Structures, An International J Vol.8 No.3

This paper presents results of fire tests on corrugated sheets used as load bearing structure of roofs of industrial buildings. Additional tests of bolted sheet connections to the supporting structure at ambient and elevated temperatures are described. Three connection types were tested and their resistance, stiffness and deformation capacity was evaluated. Finite element simulations of the corrugated sheet based on the experimental observations are briefly described and design models are presented.

Size Effect on Biaxial Flexural Strength of Concrete

Zi, Goangseup,Kim, Jihwan,Baž,ant, Zdeně,k P. American Concrete Institute 2014 ACI materials journal Vol.111 No.3

<P>The size effect on the tensile strength of concrete is investigated experimentally for the case of equi-biaxial tension. Tests of tensile strength under uniaxial tension were carried out for comparison using four-point bend beams. For measuring the biaxial tensile strength, the ASTM C1550 test and the biaxial flexure test were examined. To study the size effect, unreinforced circular plates of three different sizes are tested, with 13 specimens per size. The size effect on the equi-biaxial tensile strength is found to be stronger than it is on the uniaxial tensile strength, and to exhibit the characteristics of the deterministic Type I size effect. The detailed experimental procedure and the results are reported in this paper Under the assumption that a distinct continuous crack develops only after the peak load, the approximate law of size effect is derived from the stress redistribution due to a boundary layer of cracking. The analysis leads to a deterministic Type I size effect.</P>

Impact of postoperative complications on clinical and economic consequences in pancreatic surgery

Filip ?e?ka,Bohumil Jon,Eva ?ermakova,Zden?k ?ubrt,Alexander Ferko 대한외과학회 2015 Annals of Surgical Treatment and Research Vol.90 No.1

Purpose: Patients who develop complications consume a disproportionately large share of available resources in surgery; therefore the attention of healthcare funders focuses on the economic impact of complications. The main objective of this work was to assess the clinical and economic impact of postoperative complications in pancreatic surgery, and furthermore to assess risk factors for increased costs. Methods: In all, 161 consecutive patients underwent pancreatic resection. The costs of the treatment were determined and analyzed. Results: The overall morbidity rate was 53.4%, and the in-hospital mortality rate was 3.7%. The median of costs for all patients without complication was 3,963 Euro, whereas the median of costs for patients with at least one complication was significantly increased at 10,670 Euro (P < 0.001). In multivariate analysis American Society of Anesthesiologists ≥ 3 (P = 0.006), multivisceral resection (P < 0.001) and any complication (P < 0.001) were independently associated with increased costs. Conclusion: Postoperative complications are associated with an increase in mortality, length of hospital stay, and hospital costs. The treatment costs increase with the severity of the postoperative complications. Those factors that are known to increase the treatment costs in pancreatic resection should be considered when planning patients for surgery.

Fracture and Size Effect on Strength of Plain Concrete Disks under Biaxial Flexure Analyzed by Microplane Model M7

Kirane, Kedar,Baž,ant, Zdeně,k P.,Zi, Goangseup American Society of Civil Engineers 2014 Journal of engineering mechanics Vol.140 No.3

The biaxial tensile strength of concrete (and ceramics) can be easily tested by flexure of unreinforced circular disks. A recent experimental study demonstrated that, similar to plain concrete beams, the flexural strength of disks suffers from a significant size effect. However, the experiments did not suffice to determine the size effect type conclusively. The purpose of this study is to use three-dimensional stochastic finite-element analysis to determine the size effect type and shed more light on the fracture behavior. A finite-element code using the microplane constitutive Model M7 is verified and calibrated by fitting the previously measured load-deflections curves and fracture patterns of disks of thicknesses 30, 48, and 75 mm, similar in three dimensions, and on flexure tests on four-point loaded beams. It is found that the deformability of the supports and their lifting and sliding has a large effect on the simulations, especially on the fracture pattern, and the strength and Young's modulus of concrete must be treated as autocorrelated random fields. The calibrated model is then used to analyze the size effect over a much broader range of disk thicknesses ranging from 20 to 192 mm. The disks are shown to exhibit the typical energetic size effect of Type I, that is, the disks fail (under load control) as soon as the macrofracture initiates from the smooth bottom surface. The curve of nominal strength versus size has a positive curvature and its deterministic part terminates with a horizontal asymptote. The fact that material randomness had to be introduced to fit the fracture patterns confirms that the Type 1 size effect must terminate at very large sizes with a Weibull statistical asymptote, although the disks analyzed are not large enough to discern it.