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Mathematical Modelling of the Transient Response of Pipeline

Journal of Thermal Science 2016年第6期25卷 549-557页

作者： Dawid Taler Karol Kaczmarski cracow university of Technology Faculty of Environmental Engineering cracow university of Technology Faculty of Mechanical Engineering

Steam pipelines applied in power units operate at high pressures and *** addition,to stress from the pipeline pressure also arise high thermal stresses in transient states such as start-up,shutdown or a load change of the power ***-varying stresses are often the cause of the occurrence of fatigue cracks since the plastic deformations appear at the stress concentration *** determine the transient temperature of the steam along the steam flow path and axisymmetric temperature distribution in the pipeline wall,a numerical model of pipeline heating was *** determine the transient temperature of the steam and pipeline wall the finite volume method(FVM) was used Writing the energy conservation equations for control areas around all the nodes gives a system of ordinary differential equations with respect to *** system of ordinary differential equations of the first order was solved by the Runge-Kutta method of the fourth order to give the time-temperature changes at the nodes lying in the area of the wall and *** steam pressure distribution along pipeline was determined from the solution of the momentum conservation *** on the calculated temperature distribution,thermal stresses were *** friction factor was calculated using the correlations of Churchill and Haaland,which were proposed for pipes with a rough inner *** assess the accuracy of the proposed model,numerical calculations were also performed for the thin-walled pipe,and the results were compared to the exact analytical *** of the results shows that the accuracy of the proposed model of pipeline heating is very *** paper presents examples of the determination of the transient temperature of the steam and the wall.

关键词： pipeline steam heating walled satisfactory Pipeline conservation lying Kutta Runge

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Radioprotective thermally generated free-radical dextrins

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Chinese Science Bulletin 2008年第7期53卷 984-991页

作者： Piotr TOMASIK Oskar MICHALSKI Ewa BIDZINSKA Antonina CEBULSKA-WASILEWSKA Krystyna DYREK Maciej FIEDOROWICZ Pawe OLKO Department of Chemistry Agricultural University Cracow 30149 Poland Jagiellonian university Cracow Poland Institute of Nuclear Physics Cracow Poland

Effect of doses of the X-ray radiation from 0 to 400 Gy upon granular cornstarch and dextrins (British gums, BG) thermally generated from it at 230-300℃ was recognized with quantitative EPR and IR ab-sorption spectroscopy, molecular mass distribution in the depolymerization products, Scanning Elec-tron Microscopy, and X-ray diffractometry. Fractal analysis of the profiles of molecular mass distribu-tion showed that the depolymerization involved debranching of amylopectin. Roasting of cornstarch produced BG which differed in concentration and EPR parameters of stable free radicals from BG generated by X-ray radiation. Two types of stable free radicals, with Gaussian and Lorentzian shapes of EPR signals, were recognized. The shapes of the signals and temperature dependence on free radical intensity indicated exchanging interactions of the antiferromagnetic type, causing partial quenching of the spins at-196℃ (77K). Upon X-ray irradiation, new radicals were generated, the number and stability of which strongly depended on the types of radicals present before irradiation. These radicals slowly ceased because of a repolymerization of BG on storage.

关键词：辐射防护糊精热耦合物理学

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Permanence of Economic Potential of Cities Based on Sector Development

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Chinese Geographical Science 2017年第1期27卷 123-136页

作者： Piotr RAZNIAK Slawomir DOROCKI Anna WINIARCZYK-RAZNIAK Pedagogical university of cracow ul. Podchorqzych 2 Cracow 30-084 Poland

The paper attempts to answer the following key question: how will a city′s world rank change in the face of crisis in its main economic sector? Crisis is defined here as a decline in financial performance in the given sector, which leads to the decline of its constituent firms and corporations on the world economic scene. The World Economic Center Index(WECI) has been created in order to rank cities based on the value of their resident corporations by sector and show their level of stability upon the removal of the most important sector. This provides information on the potential of each analyzed city as well as on its advanced features or area of specialization. Research has shown that nearly half the World Economic Centers are dominated by the financial and materials sectors of the economy. Different sectors dominate different regions of the world. For example, consumer staples and materials were dominant in North America, while information technology and financials were dominant in Europe. In Asia, several sectors tend to dominate the economy. Research has shown that the ability of a principal economic sector to resist economic crisis largely depends on the strength of the command and control function of a city. Finally, a high globalization level of a city is a key determinant of its susceptibility to economic crisis.

关键词： globalization economic crisis world city world economic center headquarters

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Spring Inserts for the Intensification of the Heat Exchange Process during Boiling in Vertical Tubes--Optimization of Geometric Parameters

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Journal of Thermal Science 2018年第5期27卷 440-448页

作者： NIEZGODA-ZELASKO Beata Faculty of Mechanical Engineering Institute of Thermal and Process Engineering Cracow University of Technology31-864 Cracow Poland

The paper presents new criteria for calculation of heat transfer coefficients and flow resistance during boiling inside vertical tubes with spring inserts, developed on the basis of own experimental research. Calculations of the geometric parameters of the spring insert were carried out using the Nelder-Mead optimization method for various optimization criteria(maximizing the increase ratios for heat transfer coefficient and flow resistance, minimizing entropy, own optimization criterion). The results of optimization calculations were verified by the optimization procedures available in Statistica.

关键词： boiling heat transfer flow resistance spring inserts optimization

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Identification of landing sites for rescue helicopters in mountains with use of Geographic Information Systems

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Journal of Mountain Science 2020年第2期17卷 261-270页

作者： KROH Pawe? Institute of Geography Pedagogical University of Cracow

Helicopters are often used in mountain rescue both for rescuers moving in the area of accidents and for evacuating victims, but in steep or forested terrain finding a landing place can be problematic. The main aim of this research is to use Digital Elevation Model(DEM) and cartographic database analysis to select locations that can be used as landing site for the rescue helicopters. Methods were based on GIS analysis;both raster and vector data were used for identifying touchdown points for rescue helicopters. Based on DEM data, locations with a low slope gradient were identified;topographic vector data were used for identifying unforested sites. Then buffer zones for buildings and power lines were excluded, and it was checked whether the areas had any topographic features that prevented helicopter landings. The findings were verified on an orthophotomap. In result, GIS analyses have selected 1232 polygons that fulfilled initial criteria. Their verification on orthophotomap has shown that only 55% of them could be potentially used as landing site. Landing sites can be found mainly on side ridges of mountain ranges and in valley beds, when those on ridges are most important in this research. The greatest difficulties and methodological challenges are posed by: identification of sites having a shape which prevents landing, the obsolescence of data due to environment dynamics, the presence of features that are not shown on maps but prevent helicopter landings. A map of landing sites is a very useful tool to conduct rescue operations, but each use of a given landing site requires both in-field and numerical verification. The analysis demonstrated that GIS toolsare useful in pre-planning of rescue missions, and also showed that such data must be kept up-to-date and in-field verification is needed continuously, the more so as it plays an important role in ensuring the safety of rescuers and victims.

关键词： Helicopter mountain rescue Geographic Information Systems Digital Elevation Model Topographic databases Landing sites Geoinformation

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How rotational speed of planetary ball mill and polymer load influence the performance and water vapor sorption in solid dispersions composed of tadalafil and soluplus

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Particuology 2023年第2期73卷 37-46页

作者： Karol Kubat Anna Krupa Witold Brniak Agnieszka Węgrzyn Dorota Majda Agata Bogdał Hubert Harańczyk Department of Medical Physics Faculty of PhysicsInstitute of PhysicsJagiellonian UniversityCracowPoland Department of Pharmaceutical Technology and Biopharmaceutics Faculty of PharmacyCollegium MedicumJagiellonian UniversityCracowPoland Faculty of Chemistry Jagiellonian UniversityCracowPoland

The presence of residual water may deteriorate the performance of amorphous solid dispersions prepared by ball milling,affecting molecular mobility,crystallinity,particle size and finally,the drug dissolution *** the stability of these metastable systems depend on both formulation and process variables,the aim of this study was to assess for the first time,the impact that the polymer load and the rotational speed applied upon high energy ball milling could have on the performance of binary co-milled solid dispersions composed of tadalafil(a hydrophobic crystalline drug)and Soluplus(an amphiphilic,hygroscopic amorphous polymer).Each of these variables was tested at three *** electron microscopy,laser diffraction and X-ray powder diffraction were used to analyze morphology,particle size distribution and crystallinity of ball milled formulations *** studies were also carried *** tools of applied physics,namely solid state 1H NMR and relaxometry were used to assess the structure and water mobility upon gaseous phase hydration on *** was shown that both tested variables determined the particle size of the *** the rotational speed of 400 rpm was used,all solid dispersion were XRD-amorphous,but to ensure the immediate release of tadalafil its micellar solubilization in Soluplus was *** the formulation was exposed to water vapor,the hydration level increased with an increasing polymer load as ***,the rotational speed governed the space available for the adsorption of water molecules and their organization in a monolayer or *** behavior may have impact on the kinetics of the amorphous drug recrystallization,and finally deteriorate its dissolution.

关键词： Tadalafil Soluplus Solid dispersion Relaxation time Milling NMR

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Control Valve with a Constant Inner Authority Value

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Journal of Thermal Science 2018年第5期27卷 487-495页

作者： MUNIAK Damian Piotr Department of Thermal Power Engineering Cracow University of Technology

The aim of the article is to propose the method of designing double regulation control valves used in heating installations, allowing to obtain a constant value of the so-called inner authority and thus the constancy of the valve control characteristic, regardless of the pre-setting value set on the valve. The shape of the valve's regulation characteristics is one of the main factors determining the quality of the quantitative regulation, and thus the stability of the system's operation and overall operating costs. For this reason, the issue discussed in the article is important and can be applied in practical implementations of the valve sizing and the valve selection. The analysis was based on the relations binding the hydraulic resistances occurring inside the control valve, and the corresponding flow factors, using original author's proposal. The experimental verification was performed on a special measuring stand prepared for this purpose, measuring the values of the medium volume flow at a constant differential pressure, and then the results were converted into values of the flow factor, used in the proposed mathematical model. The results confirm the thesis put forward and the proposed mathematical model. High convergence of the results of experimental verification with the proposed mathematical model was obtained.

关键词： control valve valve authority pre-setting heating installation hydraulic balancing

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Vibrational spectroscopy-are we close to finding a solution for early pancreatic cancer diagnosis?

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World Journal of Gastroenterology 2023年第1期29卷 96-109页

作者： Krzysztof Szymoński Łukasz Chmura Ewelina Lipiec Dariusz Adamek Department of Pathomorphology Jagiellonian University Medical CollegeCracow 33-332Poland Department of Pathomorphology University Hospital in CracowCracow 31-501Poland M.Smoluchowski Institute of Physics Jagiellonian UniversityCracow 30-348Poland Department of Neuropathology Jagiellonian University Medical CollegeCracow 33-332Poland

Pancreatic cancer(PC)is an aggressive and lethal neoplasm,ranking seventh in the world for cancer deaths,with an overall 5-year survival rate of below 10%.The knowledge about PC pathogenesis is rapidly *** aspects of tumor biology,including its molecular and morphological heterogeneity,have been reported to explain the complicated“cross-talk”that occurs between the cancer cells and the tumor stroma or the nature of pancreatic ductal adenocarcinoma-associated neural ***,currently,there are no specific and sensitive diagnosis options for *** spectroscopy(VS)shows a promising role in the development of early diagnosis *** this review,we summarize recent reports about improvements in spectroscopic methodologies,briefly explain and highlight the drawbacks of each of them,and discuss available *** important aspects of spectroscopic data evaluation with multivariate analysis and a convolutional neural network methodology are *** conclude by presenting a study design for systemic verification of the VS-based methods in the diagnosis of PC.

关键词： Spectroscopic cancer diagnosis Raman spectroscopy Pancreatic cancer diagnosis DNA methylation Liquid biopsy biomarkers Convolutional neural networks

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Optimum Heating of Thick-Walled Pressure Components Assuming a Quasi-steady State of Temperature Distribution

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Journal of Thermal Science 2016年第4期25卷 380-388页

作者： Piotr Dzierwa Marcin Trojan Dawid Taler Katarzyna Kamińska Jan Taler Institute of Thermal Power Engineering Cracow University of Technology Institute of Thermal Engineering and Air Protection Faculty of Environmental Engineering Department of Hydraulic Engineering and Geotechnics Agricultural University of Cracow

As a result of the development of wind farms,the gas- steam blocks,which shall quickly ensure energy supply in case the wind velocity is too low,are introduced to the energy *** shorten the start-up time of the gas-steam and conventional blocks,the structure of the basic components of the blocks are changed,*** reducing the diameter of the boiler,the thickness of its wall is also *** attempts were also made to revise the currently binding TRD 301 regulations,replacing them by the EN 12952-3 European Standard,to reduce the allowable heating and cooling rates of thick walled boiler *** basic assumption,on which the boiler regulations allowing to calculate the allowable temperature change rates of pressure components were based,was the quasi- steady state of the temperature field in the simple shaped component,such as a slab,cylindrical or spherical wall.

关键词： pressure component thermal stress quasi-steady state optimum heating

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On Plane Stress State and Stress Free Deformation of Thick Plate with FGM Interface under Thermal Loading

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Journal of Thermal Science 2016年第5期25卷 440-448页

作者： Damian Szubartowski Artur Ganczarski Department of Mechanical Engineering Institute of Applied MechanicsCracow University of Technology

This paper demonstrates the plane stress state and the stress free thermo-elastic deformation of FGM thick plate under thermal ***,the Sneddon-Lockett theorem on the plane stress state in an isotropic infinite thick plate is generalized for a case of FGM problem in which all thermo-mechanical properties are optional functions of depth *** proof is based on application of the Iljushin thermo-elastic potential to displacement type system of equations that reduces it to the plane stress state *** an existence of the purely thermal deformation is proved in two ways:first,it is shown that the unique solution fulfils conditions of simultaneous constant temperature and linear gradation of thermal expansion coefficient,second,proof is based directly on stress type system of equations which straightforwardly reduces to compatibility equations for purely thermal deformation if only stress field is homogeneous in domain and at ***,couple examples of application to an engineering problem are presented.

关键词： thick plate with FGM interface plane stress state stress free deformation

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