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Detalles de la revista
Formato
Revista
eISSN
2353-737X
Publicado por primera vez
20 May 2020
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

Volumen 114 (2017): Edición 8 (August 2017)

Detalles de la revista
Formato
Revista
eISSN
2353-737X
Publicado por primera vez
20 May 2020
Periodo de publicación
1 tiempo por año
Idiomas
Inglés

Buscar

20 Artículos
Acceso abierto

Class II Mechanisms in the Construction of Retractable Roofs

Publicado en línea: 26 May 2020
Páginas: 5 - 15

Resumen

Abstract

This work presents retractable roofs of new designs based on class II mechanisms. Firstly, roofs that are currently in existence were analysed in terms of the mechanisms involved in their construction. Then, the possibility of constructing a roof based on the variety of quadruples in which all links are joined with roof panels was investigated. The boundary conditions that have to be fulfilled by such a construction were specified. Ultimately, research models were constructed with the use of construction solutions similar to those applied in buildings currently in existence.

Palabras clave

  • membrane roof
  • retractable roof
  • mechanisms class II
Acceso abierto

Oscar Niemeyer’s Ibirapuera Park in São Paulo Built with One Line

Publicado en línea: 26 May 2020
Páginas: 17 - 28

Resumen

Abstract

Niemeyer’s extraordinary ability to present his projects with one line comes from the inspiration of the landscape, the hills surrounding Copacabana Beach, and the female body. Sketching since he was younger, the architect has improved his line so much that one line was enough to explain the whole project. One of the realizations built with one line was the Ibirapuera Park in São Paulo, opened in 1954. The buildings created there, showed a glimpse of Sugarloaf Mountain, women and their curvilinear forms.

Palabras clave

  • Oscar Niemeyer
  • Parque Ibirapuera
  • women
  • São Paulo
Acceso abierto

Determination of the Diastase Activity in Honeys

Publicado en línea: 26 May 2020
Páginas: 29 - 35

Resumen

Abstract

The diastatic number in five samples of honey has been determined by two methods: according to guidelines included in Polish standard PN-88/A-77626 and the Phadebas method. Research shows that the storage of honeys did not have a significant impact on lowering of diastatic number. However, long-term storage of honey was characterized a reduction of the diastase number. The correlation between the two applied methods was very strong (r = 0.921).

Palabras clave

  • diastase number
  • honey
Acceso abierto

Modern Information Management throughout a Construction Project Life Cycle – Selected Issues Concerning Digitization in Construction and a Case Study

Publicado en línea: 26 May 2020
Páginas: 37 - 51

Resumen

Abstract

The use of innovative technologies and digitisation tools may significantly improve the preparation and execution of a construction project. The article discusses the results of the latest research concerning digitisation in construction and an innovative model of communication between participants of a construction project in reference to the Building Information Modelling method, the concept of Integrated Project Delivery and Facility Management principles. Conclusions from the analysis of results of implementation of innovative, digital tools and information management techniques will be presented using case studies of three construction projects - the construction of the New Karolinska Solna University Hospital in the Stockholm region, an office building in Wrocław and the expansion of the national road No. 8 to meet the parameters of an express road at the Wyszków–Poręba hub.

Palabras clave

  • information management
  • digitisation
  • BIM
  • construction project life cycle
  • Facility Management
Acceso abierto

Selection of a Cooperation Model in Investments Implemented in the System of Public-Private Partnership in Poland

Publicado en línea: 26 May 2020
Páginas: 53 - 60

Resumen

Abstract

Public-private partnership is a form of investment implementation based on the distribution of tasks, responsibilities and the form of risk among the public and private parties. This division enables the most economically efficient means of investment implementation to be achieved. The paper presents an analysis of the selection of a cooperation model concerning the parties in public-private partnership, depending on the sector and specificity of the task.

Palabras clave

  • public-private partnership
  • concession
  • cooperation model
Acceso abierto

Competitiveness of a Building Company within the Organisational Life Cycle

Publicado en línea: 26 May 2020
Páginas: 61 - 71

Resumen

Abstract

The role and the meaning of a construction company on the market is variable depending on the phase of the life cycle of the company in a given moment. The processes and the services offered by a company are dependent on time and how the business activities of the company are developed as well as the barriers which the company encounters at specific stages of the business activities of the enterprise. In this specific context competitiveness can be understood not only as a comparison of the position of the company with other enterprises functioning within a given sector but as a resultant of possibilities and chances created by an organization in the context of its life cycle. The main aim of this article is to try and assess the influence of the life cycle of a construction company on its market behaviour taking into account the theoretical consideration of competitiveness.

Palabras clave

  • organizational life cycle
  • competitiveness
  • barriers of entry
Acceso abierto

Quantitative Estimation of the Impact of Random Confounding Factors on the Duration and Cost of Construction Works

Publicado en línea: 26 May 2020
Páginas: 73 - 79

Resumen

Abstract

Random events may interfere with the execution process and results of the work. Then, the duration and cost of work are random variables. The random characteristics of these variables are described by using the β-PERT probability distribution and the simplified formulas. To determine the probable changes of the duration and cost of work, depending on the random factors, the coefficients of optimism and pessimism have been used. Additionally, the coefficients of improvement and deterioration of conditions of work implementation have been introduced. The values of these coefficients are calculated depending on the type, the probability of occurrence, the intensity of random perturbations and depending on the probable changes of the work duration as well as the probability and cost consequences of the price increase. Extreme random improvement and deterioration of the work execution conditions are analysed.

Palabras clave

  • construction
  • risk
  • coefficients of optimism and pessimism
Acceso abierto

Air Flow Formation in the Inlet of a Closed Circuit Boundary Layer Wind Tunnel using the One-Set Guide Vanes Solution

Publicado en línea: 26 May 2020
Páginas: 81 - 98

Resumen

Abstract

The paper presents tests of wind velocity distribution at the inlet to the working section of a wind tunnel. Unconventional guide vanes were introduced in the construction of the wind tunnel to obtain a uniform air flow in this area.

Palabras clave

  • wind tunnel
  • guide vanes
  • uniform wind velocity distribution
Acceso abierto

Green Public Procurement for Water Infrastructure in the Context of Sustainable Development and Respect for Water

Publicado en línea: 26 May 2020
Páginas: 99 - 107

Resumen

Abstract

The paper presents the results of research aimed at examining how public institutions implement sustainable development policy at the stage of preparation of tender documentation for construction and extension of wastewater treatment plants and water and wastewater infrastructure. The most important assumptions of sustainable development policy at national and European level are also briefly discussed.

Palabras clave

  • sustainable development
  • water infrastructure
  • green public procurement
Acceso abierto

Optimization of Construction Schedules with the Assumed Multi-Tasking of Working Brigades

Publicado en línea: 26 May 2020
Páginas: 109 - 118

Resumen

Abstract

The paper presents a newly developed model aimed at minimizing the downtime in working brigades work. The developed method is dedicated to the construction planned using the stream method of work organization. The model focuses on the assumption of multi-tasking of working brigades. It has been possible to model the performance depending on the type of brigade and the type of work being performed. The article also shows an example illustrating the results of the model’s operation.

Palabras clave

  • flowshop models
  • slack minimization
  • construction schedules
Acceso abierto

Model for Assessing “Accessibility” – the Basic Category in the Evaluation of Social Performance of Buildings According to Standards PN-EN 16309+A1:2014-12

Publicado en línea: 26 May 2020
Páginas: 119 - 127

Resumen

Abstract

The paper considers the assessment model of the category Accessibility, which is a basic element of the social aspect of sustainable construction. The model takes into account the standard PN-EN 16309+A1:2014-12, which generally provides methods and requirements for assessing the social performance of buildings. The authors, for the purposes of the model particularise the scope of the assessment category and set threshold values and the weight of particular social indicators. The model is treated as a contribution to developing a method for comprehensive assessment of the social characteristics of buildings.

Palabras clave

  • Technical Committee CEN / TC 350
  • the social aspect
  • accessibility
  • model
Acceso abierto

Utility Assessment of Biomass Fly-Ash for Production of Concrete Products

Publicado en línea: 26 May 2020
Páginas: 129 - 142

Resumen

Abstract

International agreements oblige our state to develop ecological sources of energy, one of which is biomass. During its combustion fly-ashes are produced. Several studies have shown that they might be useful in concrete production. The article presents a comparison of biomass fly-ash and coal fly-ash influence on the properties of cement composites. The replacement levels of cement by fly-ash (FA) were 20%, 40% and 60%. Biomass fly-ash FA(B) have replaced coal fly-ash by 0%, 50% and 100%. The compressive strength tests showed similarities in strength development of coal and biomass fly-ashes concretes. Specimens with biomass fly-ash presented similar or better abrasion resistance comparing to coal fly-ash samples.

Palabras clave

  • biomass fly-ash
  • cement
  • concrete
Acceso abierto

Environmental Assessment in the Integrated Life Cycle Design of Buildings

Publicado en línea: 26 May 2020
Páginas: 143 - 151

Resumen

Abstract

The paper discusses the issue of building environmental assessments carried out as part of an integrated life cycle design process. The paper presents the methods used to evaluate environmental impact based on CEN and ISO standards. The paper concludes with an excerpt from an environmental assessment of a reinforced concrete structural frame in an office building.

Palabras clave

  • sustainable construction
  • ILCD
  • LCA
Acceso abierto

Contaminants in Circulating Refrigerant

Publicado en línea: 26 May 2020
Páginas: 153 - 163

Resumen

Abstract

Contaminants are inventible in the refrigeration cycle. Lubricant, water and moist air are the main contaminants in circulated refrigerant. This paper attempts to show how the presence of such contaminants influences the thermodynamic parameters of the refrigerating cycle and the mixture, which comes at the beginning..

Palabras clave

  • refrigerant
  • contaminants
  • mixture
  • specific enthalpy
  • thermodynamic cycle
  • refrigerating cycle
  • positivedisplacement compressor
Acceso abierto

Uniqueness of Solutions to Inverse Parabolic Semilinear Problems under Nonlocal Conditions with Integrals

Publicado en línea: 26 May 2020
Páginas: 165 - 175

Resumen

Abstract

The uniqueness of classical solutions to inverse parabolic semilinear problems together with nonlocal initial conditions with integrals, for the operator i,j=1nxi(aij(x,t)xj)+v(x,t)-t,\sum\limits_{i,j = 1}^n {{\partial \over {\partial {x_i}}}\left( {{a_{ij}}\left( {x,t} \right){\partial \over {\partial {x_j}}}} \right)} + v\left( {x,t} \right) - {\partial \over {\partial t}},, x=(x1,..., xn), in the cylindrical domain D:= D0×(t0, t0+T) ⊂ℜn+1, where t0∈ℜ, 0 < T <∞ are studied. The result consists in the introduction of nonlocal conditions with integrals.

Palabras clave

  • inverse problems
  • parabolic problems
  • semilinear equation
  • nonlocal condition with integral
  • cylindrical domain
  • uniqueness of solutions
Acceso abierto

Application of Cone Beam Computed Tomography for Detection of Periapical Lesions – Clinical Case

Publicado en línea: 26 May 2020
Páginas: 177 - 185

Resumen

Abstract

The purpose of the thesis is to show the dental imaging capability of Cone Beam Computed Tomography (CBCT) in comparison with intraoral X-ray images for detection and assessment of periapical lesions before and during treatment as well as to present the use of diagnostic functions in the available software. The thesis presents two clinical cases.

Palabras clave

  • CBCT
  • volumetric tomography
  • periapical lesions
  • dental imaging
Acceso abierto

An Analysis of the Steam Superheater Coil Operation Depending on Different Methods of Coil Support

Publicado en línea: 26 May 2020
Páginas: 187 - 192

Resumen

Abstract

The paper presents the main types of power boiler steam superheater loads together with relevant standards applicable to superheater calculations. In the case of horizontal superheaters, due to their thermal expansion and assembly errors which are the effect of non-uniform support of the hanger tubes, extra loads are generated on the coil pipes. An FEM analysis performed for a selected superheater structure indicates that maximum stress values and the location where the stresses occur depend on the method of support of the superheater tubes. It is shown that maximum stresses in this structural element can be reduced by introducing appropriate tension of hanger bars supporting the superheater hanger tubes.

Palabras clave

  • power boiler
  • creep
  • stress
  • FEM analysis
Acceso abierto

Application of Ishikawa Diagram for Failure Analysis of a Car Water Pump

Publicado en línea: 26 May 2020
Páginas: 193 - 198

Resumen

Abstract

The paper presents an identification of potential causes and effects of failures of a coolant pump for internal combustion engines. Ishikawa’s quality improvement tools have been used to analyze the defects. The main causes of pump failures and cause-effect relationships have been identified. The main causes were identified and classified in order to select those which have the greatest influence on pump damage during operation.

Palabras clave

  • Ishikawa diagram
  • coolant pump
Acceso abierto

Hermite Interpolation of Multivariable Function Given at Scattered Points

Publicado en línea: 26 May 2020
Páginas: 199 - 205

Resumen

Abstract

The paper shows the approach to the interpolation of scattered data which includes not only function values, but also values of derivatives of the function. To this end, an interpolant composed of radial basis functions is used and extended by terms possessing appropriate derivative terms. The latter match the given derivatives. Special attention is paid to the problem of choosing the value of the shape parameter, which is included in radial functions and influences the accuracy and stability of the solution. To validate the method, several numerical tests are carried out in the paper.

Palabras clave

  • scattered data interpolation
  • Hermite interpolation
  • radial basis functions
Acceso abierto

Comparison of Computing Efficiency of Different Hydraulic Vehicle Damper Models

Publicado en línea: 26 May 2020
Páginas: 207 - 214

Resumen

Abstract

This paper deals with comparisons of computing efficiency of 20 damper models with functional and hybrid approaches, which can be used to solve typical problems in vehicle dynamics. Efficiency is evaluated based on model accuracy and computing time. The computed results of different damper models are compared to measurements of an actual car damper. Its damping characteristics were measured on a hydraulic damper test rig with three different excitations.

Palabras clave

  • vehicle dynamics
  • modelling
  • hydraulic damper
  • shock absorber
20 Artículos
Acceso abierto

Class II Mechanisms in the Construction of Retractable Roofs

Publicado en línea: 26 May 2020
Páginas: 5 - 15

Resumen

Abstract

This work presents retractable roofs of new designs based on class II mechanisms. Firstly, roofs that are currently in existence were analysed in terms of the mechanisms involved in their construction. Then, the possibility of constructing a roof based on the variety of quadruples in which all links are joined with roof panels was investigated. The boundary conditions that have to be fulfilled by such a construction were specified. Ultimately, research models were constructed with the use of construction solutions similar to those applied in buildings currently in existence.

Palabras clave

  • membrane roof
  • retractable roof
  • mechanisms class II
Acceso abierto

Oscar Niemeyer’s Ibirapuera Park in São Paulo Built with One Line

Publicado en línea: 26 May 2020
Páginas: 17 - 28

Resumen

Abstract

Niemeyer’s extraordinary ability to present his projects with one line comes from the inspiration of the landscape, the hills surrounding Copacabana Beach, and the female body. Sketching since he was younger, the architect has improved his line so much that one line was enough to explain the whole project. One of the realizations built with one line was the Ibirapuera Park in São Paulo, opened in 1954. The buildings created there, showed a glimpse of Sugarloaf Mountain, women and their curvilinear forms.

Palabras clave

  • Oscar Niemeyer
  • Parque Ibirapuera
  • women
  • São Paulo
Acceso abierto

Determination of the Diastase Activity in Honeys

Publicado en línea: 26 May 2020
Páginas: 29 - 35

Resumen

Abstract

The diastatic number in five samples of honey has been determined by two methods: according to guidelines included in Polish standard PN-88/A-77626 and the Phadebas method. Research shows that the storage of honeys did not have a significant impact on lowering of diastatic number. However, long-term storage of honey was characterized a reduction of the diastase number. The correlation between the two applied methods was very strong (r = 0.921).

Palabras clave

  • diastase number
  • honey
Acceso abierto

Modern Information Management throughout a Construction Project Life Cycle – Selected Issues Concerning Digitization in Construction and a Case Study

Publicado en línea: 26 May 2020
Páginas: 37 - 51

Resumen

Abstract

The use of innovative technologies and digitisation tools may significantly improve the preparation and execution of a construction project. The article discusses the results of the latest research concerning digitisation in construction and an innovative model of communication between participants of a construction project in reference to the Building Information Modelling method, the concept of Integrated Project Delivery and Facility Management principles. Conclusions from the analysis of results of implementation of innovative, digital tools and information management techniques will be presented using case studies of three construction projects - the construction of the New Karolinska Solna University Hospital in the Stockholm region, an office building in Wrocław and the expansion of the national road No. 8 to meet the parameters of an express road at the Wyszków–Poręba hub.

Palabras clave

  • information management
  • digitisation
  • BIM
  • construction project life cycle
  • Facility Management
Acceso abierto

Selection of a Cooperation Model in Investments Implemented in the System of Public-Private Partnership in Poland

Publicado en línea: 26 May 2020
Páginas: 53 - 60

Resumen

Abstract

Public-private partnership is a form of investment implementation based on the distribution of tasks, responsibilities and the form of risk among the public and private parties. This division enables the most economically efficient means of investment implementation to be achieved. The paper presents an analysis of the selection of a cooperation model concerning the parties in public-private partnership, depending on the sector and specificity of the task.

Palabras clave

  • public-private partnership
  • concession
  • cooperation model
Acceso abierto

Competitiveness of a Building Company within the Organisational Life Cycle

Publicado en línea: 26 May 2020
Páginas: 61 - 71

Resumen

Abstract

The role and the meaning of a construction company on the market is variable depending on the phase of the life cycle of the company in a given moment. The processes and the services offered by a company are dependent on time and how the business activities of the company are developed as well as the barriers which the company encounters at specific stages of the business activities of the enterprise. In this specific context competitiveness can be understood not only as a comparison of the position of the company with other enterprises functioning within a given sector but as a resultant of possibilities and chances created by an organization in the context of its life cycle. The main aim of this article is to try and assess the influence of the life cycle of a construction company on its market behaviour taking into account the theoretical consideration of competitiveness.

Palabras clave

  • organizational life cycle
  • competitiveness
  • barriers of entry
Acceso abierto

Quantitative Estimation of the Impact of Random Confounding Factors on the Duration and Cost of Construction Works

Publicado en línea: 26 May 2020
Páginas: 73 - 79

Resumen

Abstract

Random events may interfere with the execution process and results of the work. Then, the duration and cost of work are random variables. The random characteristics of these variables are described by using the β-PERT probability distribution and the simplified formulas. To determine the probable changes of the duration and cost of work, depending on the random factors, the coefficients of optimism and pessimism have been used. Additionally, the coefficients of improvement and deterioration of conditions of work implementation have been introduced. The values of these coefficients are calculated depending on the type, the probability of occurrence, the intensity of random perturbations and depending on the probable changes of the work duration as well as the probability and cost consequences of the price increase. Extreme random improvement and deterioration of the work execution conditions are analysed.

Palabras clave

  • construction
  • risk
  • coefficients of optimism and pessimism
Acceso abierto

Air Flow Formation in the Inlet of a Closed Circuit Boundary Layer Wind Tunnel using the One-Set Guide Vanes Solution

Publicado en línea: 26 May 2020
Páginas: 81 - 98

Resumen

Abstract

The paper presents tests of wind velocity distribution at the inlet to the working section of a wind tunnel. Unconventional guide vanes were introduced in the construction of the wind tunnel to obtain a uniform air flow in this area.

Palabras clave

  • wind tunnel
  • guide vanes
  • uniform wind velocity distribution
Acceso abierto

Green Public Procurement for Water Infrastructure in the Context of Sustainable Development and Respect for Water

Publicado en línea: 26 May 2020
Páginas: 99 - 107

Resumen

Abstract

The paper presents the results of research aimed at examining how public institutions implement sustainable development policy at the stage of preparation of tender documentation for construction and extension of wastewater treatment plants and water and wastewater infrastructure. The most important assumptions of sustainable development policy at national and European level are also briefly discussed.

Palabras clave

  • sustainable development
  • water infrastructure
  • green public procurement
Acceso abierto

Optimization of Construction Schedules with the Assumed Multi-Tasking of Working Brigades

Publicado en línea: 26 May 2020
Páginas: 109 - 118

Resumen

Abstract

The paper presents a newly developed model aimed at minimizing the downtime in working brigades work. The developed method is dedicated to the construction planned using the stream method of work organization. The model focuses on the assumption of multi-tasking of working brigades. It has been possible to model the performance depending on the type of brigade and the type of work being performed. The article also shows an example illustrating the results of the model’s operation.

Palabras clave

  • flowshop models
  • slack minimization
  • construction schedules
Acceso abierto

Model for Assessing “Accessibility” – the Basic Category in the Evaluation of Social Performance of Buildings According to Standards PN-EN 16309+A1:2014-12

Publicado en línea: 26 May 2020
Páginas: 119 - 127

Resumen

Abstract

The paper considers the assessment model of the category Accessibility, which is a basic element of the social aspect of sustainable construction. The model takes into account the standard PN-EN 16309+A1:2014-12, which generally provides methods and requirements for assessing the social performance of buildings. The authors, for the purposes of the model particularise the scope of the assessment category and set threshold values and the weight of particular social indicators. The model is treated as a contribution to developing a method for comprehensive assessment of the social characteristics of buildings.

Palabras clave

  • Technical Committee CEN / TC 350
  • the social aspect
  • accessibility
  • model
Acceso abierto

Utility Assessment of Biomass Fly-Ash for Production of Concrete Products

Publicado en línea: 26 May 2020
Páginas: 129 - 142

Resumen

Abstract

International agreements oblige our state to develop ecological sources of energy, one of which is biomass. During its combustion fly-ashes are produced. Several studies have shown that they might be useful in concrete production. The article presents a comparison of biomass fly-ash and coal fly-ash influence on the properties of cement composites. The replacement levels of cement by fly-ash (FA) were 20%, 40% and 60%. Biomass fly-ash FA(B) have replaced coal fly-ash by 0%, 50% and 100%. The compressive strength tests showed similarities in strength development of coal and biomass fly-ashes concretes. Specimens with biomass fly-ash presented similar or better abrasion resistance comparing to coal fly-ash samples.

Palabras clave

  • biomass fly-ash
  • cement
  • concrete
Acceso abierto

Environmental Assessment in the Integrated Life Cycle Design of Buildings

Publicado en línea: 26 May 2020
Páginas: 143 - 151

Resumen

Abstract

The paper discusses the issue of building environmental assessments carried out as part of an integrated life cycle design process. The paper presents the methods used to evaluate environmental impact based on CEN and ISO standards. The paper concludes with an excerpt from an environmental assessment of a reinforced concrete structural frame in an office building.

Palabras clave

  • sustainable construction
  • ILCD
  • LCA
Acceso abierto

Contaminants in Circulating Refrigerant

Publicado en línea: 26 May 2020
Páginas: 153 - 163

Resumen

Abstract

Contaminants are inventible in the refrigeration cycle. Lubricant, water and moist air are the main contaminants in circulated refrigerant. This paper attempts to show how the presence of such contaminants influences the thermodynamic parameters of the refrigerating cycle and the mixture, which comes at the beginning..

Palabras clave

  • refrigerant
  • contaminants
  • mixture
  • specific enthalpy
  • thermodynamic cycle
  • refrigerating cycle
  • positivedisplacement compressor
Acceso abierto

Uniqueness of Solutions to Inverse Parabolic Semilinear Problems under Nonlocal Conditions with Integrals

Publicado en línea: 26 May 2020
Páginas: 165 - 175

Resumen

Abstract

The uniqueness of classical solutions to inverse parabolic semilinear problems together with nonlocal initial conditions with integrals, for the operator i,j=1nxi(aij(x,t)xj)+v(x,t)-t,\sum\limits_{i,j = 1}^n {{\partial \over {\partial {x_i}}}\left( {{a_{ij}}\left( {x,t} \right){\partial \over {\partial {x_j}}}} \right)} + v\left( {x,t} \right) - {\partial \over {\partial t}},, x=(x1,..., xn), in the cylindrical domain D:= D0×(t0, t0+T) ⊂ℜn+1, where t0∈ℜ, 0 < T <∞ are studied. The result consists in the introduction of nonlocal conditions with integrals.

Palabras clave

  • inverse problems
  • parabolic problems
  • semilinear equation
  • nonlocal condition with integral
  • cylindrical domain
  • uniqueness of solutions
Acceso abierto

Application of Cone Beam Computed Tomography for Detection of Periapical Lesions – Clinical Case

Publicado en línea: 26 May 2020
Páginas: 177 - 185

Resumen

Abstract

The purpose of the thesis is to show the dental imaging capability of Cone Beam Computed Tomography (CBCT) in comparison with intraoral X-ray images for detection and assessment of periapical lesions before and during treatment as well as to present the use of diagnostic functions in the available software. The thesis presents two clinical cases.

Palabras clave

  • CBCT
  • volumetric tomography
  • periapical lesions
  • dental imaging
Acceso abierto

An Analysis of the Steam Superheater Coil Operation Depending on Different Methods of Coil Support

Publicado en línea: 26 May 2020
Páginas: 187 - 192

Resumen

Abstract

The paper presents the main types of power boiler steam superheater loads together with relevant standards applicable to superheater calculations. In the case of horizontal superheaters, due to their thermal expansion and assembly errors which are the effect of non-uniform support of the hanger tubes, extra loads are generated on the coil pipes. An FEM analysis performed for a selected superheater structure indicates that maximum stress values and the location where the stresses occur depend on the method of support of the superheater tubes. It is shown that maximum stresses in this structural element can be reduced by introducing appropriate tension of hanger bars supporting the superheater hanger tubes.

Palabras clave

  • power boiler
  • creep
  • stress
  • FEM analysis
Acceso abierto

Application of Ishikawa Diagram for Failure Analysis of a Car Water Pump

Publicado en línea: 26 May 2020
Páginas: 193 - 198

Resumen

Abstract

The paper presents an identification of potential causes and effects of failures of a coolant pump for internal combustion engines. Ishikawa’s quality improvement tools have been used to analyze the defects. The main causes of pump failures and cause-effect relationships have been identified. The main causes were identified and classified in order to select those which have the greatest influence on pump damage during operation.

Palabras clave

  • Ishikawa diagram
  • coolant pump
Acceso abierto

Hermite Interpolation of Multivariable Function Given at Scattered Points

Publicado en línea: 26 May 2020
Páginas: 199 - 205

Resumen

Abstract

The paper shows the approach to the interpolation of scattered data which includes not only function values, but also values of derivatives of the function. To this end, an interpolant composed of radial basis functions is used and extended by terms possessing appropriate derivative terms. The latter match the given derivatives. Special attention is paid to the problem of choosing the value of the shape parameter, which is included in radial functions and influences the accuracy and stability of the solution. To validate the method, several numerical tests are carried out in the paper.

Palabras clave

  • scattered data interpolation
  • Hermite interpolation
  • radial basis functions
Acceso abierto

Comparison of Computing Efficiency of Different Hydraulic Vehicle Damper Models

Publicado en línea: 26 May 2020
Páginas: 207 - 214

Resumen

Abstract

This paper deals with comparisons of computing efficiency of 20 damper models with functional and hybrid approaches, which can be used to solve typical problems in vehicle dynamics. Efficiency is evaluated based on model accuracy and computing time. The computed results of different damper models are compared to measurements of an actual car damper. Its damping characteristics were measured on a hydraulic damper test rig with three different excitations.

Palabras clave

  • vehicle dynamics
  • modelling
  • hydraulic damper
  • shock absorber

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