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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 6 (June 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
access type Acceso abierto

A Comparative Analysis of the Index Assessment of Church Acoustics using RASTI and STI

Publicado en línea: 26 May 2020
Páginas: 5 - 19

Resumen

Abstract

The article presents modified global assessment indices, developed in previous studies, for measuring the acoustic quality of Roman Catholic churches: the four-parameter Gap index and the Gi index based on five acoustic parameters. The replacement of RASTI, previously used in the acoustic assessment of churches, with STI has broadened the scope of church assessment and contributed to an improvement in the accuracy of the proposed method. Verification of new calculation procedures was performed on the 12 churches included in the calculation model and, additionally, on another church.

Palabras clave

  • church acoustics
  • index method
  • acoustic quality
access type Acceso abierto

Representation of Architectural Idea and Interpretation as Part of the Protection of Cultural Heritage

Publicado en línea: 26 May 2020
Páginas: 21 - 30

Resumen

Abstract

Architecture and urban planning, classified as technical disciplines of science, in their records of creative works, also maintain representations of architectural ideas in the form of drawings, sketches or paintings. Ancillary to national heritage collections, they are an extensive source of information, which links the autonomous vision of the creator with the form outline, thus, creating an external context of such a form. Original architectural notations are part of the documentation of designs that were later executed and those that failed to be executed at all; furthermore, they confirm the high quality of expertise and the individual approach typical of leading professionals in the field across the world. The inspiration drawn from the 20th and 21st century facilities, translated into the language of artistic expression, proves the interdisciplinarity of the architectural profession and its communicative and educational assets shall be subject to particular protection and shall be displayed in order to elevate the rank of their meaning in the design process as well as in the collection of national, cultural heritage.

Palabras clave

  • representation – document
  • artistic value
  • cognitive value
access type Acceso abierto

Chemical and Thermal Methods for Removing Ammonia from Fly Ashes

Publicado en línea: 26 May 2020
Páginas: 31 - 50

Resumen

Abstract

The presence of ammonia in ashes (i.e. ammonia slip) is a direct consequence of the methods used for denitrification – selective catalytic and non-catalytic reduction (SCR, SNCR). The excess unreacted ammonia used in both of these methods passes as a constituent to ash, impairing its properties, and thus affects the quality of the commercial product. The summary of the available methods for removing NH3 from fly ashes is presented. Both chemical and thermal methods of removing NH3are described. The results of the chemical methods depend on the kind of additional reagents used and composition of fly ashes. Thermal methods seem to be simpler and easier to use, but they are used mainly on the smaller scale.

Palabras clave

  • flyash
  • deammonisation
access type Acceso abierto

Neuro-Fuzzy Predictions of Construction Site Completion Dates

Publicado en línea: 26 May 2020
Páginas: 51 - 58

Resumen

Abstract

The results from two types of multi-layer perceptron artificial neural networks (Matlab R2015a was used) were compared. The first one, with only one neuron in an output layer having the value of delay in completion date of building site. The output layer of the second artificial neural network is created by three neurons. These three values represent the same delay, but in a form of three values of membership functions to fuzzy sets. In order to evaluate the accuracy of predictions, the mean squared error was used. It was necessary to find the best method of defuzzyfication predicted delays to compare the results from these two, aforementioned artificial neural networks. The level of prediction accuracy measured by mean squared error was discussed, too.

Palabras clave

  • MLP artificial neural networks
  • fuzzy sets
  • delays in completion dates
access type Acceso abierto

Property Valuation using Hedonic Price Method – Procedure and its Application

Publicado en línea: 26 May 2020
Páginas: 59 - 70

Resumen

Abstract

This paper discusses one of the property valuation methods, i.e. property valuation using the hedonic price method, which makes use of a classical linear regression model. The study characterises the calculation procedure of the selected method and indicates the fields of application of the hedonic approach in the construction sector. The operation of the hedonic price method is presented based on a valuation of flats in Lublin.

Palabras clave

  • property
  • property valuation
  • hedonic price method
  • classical linear regression model
  • hedonic regression
access type Acceso abierto

Dynamic Response of a Steel Pipeline with Bolted Connections to a Mining Shock Obtained with the Submodeling Technique

Publicado en línea: 26 May 2020
Páginas: 71 - 83

Resumen

Abstract

In this paper, the dynamic response of an overground steel pipeline to a real mining shock is presented. The submodeling method was used in the calculation. Firstly, time history analysis of a simplified beam model of the pipeline (a global model) was conducted. Secondly, the 3D model of a part of the structure over the support was created (a submodel). The submodeling analysis allowed obtaining stress distribution in the bolted connection of the pipeline segments.

Palabras clave

  • pipeline
  • dynamic response
  • mining shock
  • submodeling
access type Acceso abierto

Evaluation of the Technical Condition of the “Fryderyk” Adit in Tarnowskie Góry for the Purpose of Eventual Revitalization

Publicado en línea: 26 May 2020
Páginas: 85 - 99

Resumen

Abstract

The “Fryderyk” adit (renamed ‘Kościuszko’ after World War II) is the last adit built in the area of Tarnowskie Góry, and was supposed to provide drainage for the area of exploitation of the “Fryderyk” mine. After the shutdown of the mine, the adit gained an important role in the water management of the area. The water from nearby sources flows into the river Drama through the adit. The long period of the adit’s existence and the processes occurring in its area have caused a progressive process of support degradation, which increases the danger of a loss of stability and a collapse of the roof. Allowing the collapse of the adit’s roof may cause surface depressions. The article presents the research results that show an evaluation of the technical condition and safety degree of the support for future failure-free usage. A range of activities that are meant to stop the natural degradation of the end section of the adit has also been suggested.

Palabras clave

  • mining monuments
  • support
  • heading stability
  • surface deformation
access type Acceso abierto

Maintenance of Apartment Buildings and Their Measurable Deterioration

Publicado en línea: 26 May 2020
Páginas: 101 - 107

Resumen

Abstract

Apartment buildings constructed prior to the First World War are important examples of Polish buildings with regard to their historical significance – the technical maintenance of such buildings remains challenging. The results of the work refer to the general population, estimated for 600 objects, that compose of about 20% of municipal downtown apartment buildings in Wrocław. The purpose of the research was to identify an influence of widely considered maintenance of apartment houses on a degree and intensity of their elements’. The goal of this research has been achieved through the analysis of symptoms reflecting the decline of the inspected elements’ exploitation values, that is identification of mechanics of arising their defects. The calculated quantitative data can be used as the basis for identifying the structure of the building companies which are responsible for housing maintenance and repair.

Palabras clave

  • apartment buildings
  • maintenance
  • deterioration
  • technical wear
access type Acceso abierto

Analysis of Type of Construction Projects in Tender Formula “Design and Build”

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

Resumen

Abstract

The construction undertakings are being realized within two basic formulas:

▶ Design and separately execution of works – (“P”) + (“B”),

▶ Design and built – (“P+B”) otherwise called as “design and execution of works” („Z i W”).

The project realization procedure depends on the kind of undertaking and resources of the contracting authority. The choice of formula has an influence on the undertaking preparation as well as on the choice of executor and project realization. The article shows the results of research and defines the percent participation of the individual type of construction undertakings in “design and execution of work” formula that were realized in Poland in the years 2010–2016. “Design and execution of work” formula is used rarely in public procurements. The above-mentioned is confirmed by nation-wide statistic data and statistic data for the Kujawsko-Pomorskie and Warmińsko-Mazurskie provinces.

Palabras clave

  • public procurements
  • “design and build” formula
  • tendering mode
  • contracting authority
  • statistic data
access type Acceso abierto

Optimal Design of Structural Elements as a Control Theory Problem

Publicado en línea: 26 May 2020
Páginas: 119 - 134

Resumen

Abstract

In the paper an application of the maximum principle to designing a cross section of a still frame under several loading schemes is presented. The optimal height of the web under minimum volume of still as a cost function is determined. In particular the implicit and explicit conditions of state variables at characteristic points of axis of symmetry under different loading schemes are presented.

Palabras clave

  • optimal control
  • maximum principle
access type Acceso abierto

Potential Reasons for Works Delays Resulting From the Provisions of the Agreement

Publicado en línea: 26 May 2020
Páginas: 135 - 143

Resumen

Abstract

The course of the construction process in time is shaped by a variety of factors, which, in effect, may become the reason for delays in project completion. The paper presents the outcome of research performed with Polish building works contractors. One of the aims was to try to identify the potential reasons for delays in construction works, which result from the provisions of the agreement. Early recognition and an assessment of possible risks may assist the contractor’s attempts to eliminate them or to lessen the scale of delays in the project implementation.

Palabras clave

  • delays
  • construction works
  • factor identification
access type Acceso abierto

Prediction of Changes in the Performance Characteristics of a Building

Publicado en línea: 26 May 2020
Páginas: 145 - 151

Resumen

Abstract

Over the course of their use, building structures are subject to constant destructive processes, which can take various courses. Over time, performance characteristics deteriorate, and can be partially restored as a result of repair works. The article presents a proposal for the prediction of changes in the performance characteristics of a building based on the adaptation of principles applied in predicting the operational reliability of technical objects.

Palabras clave

  • degree of wear
  • prediction
  • life distribution
access type Acceso abierto

The Algorithm for the Evaluation of Construction Workers’ Labour Productivity

Publicado en línea: 26 May 2020
Páginas: 153 - 161

Resumen

Abstract

The paper presents an algorithm that allows to calculate the potential productivity of construction workers, including the factors that influence them. Its development involves one of the classifications of factors. In the next step, the elements of fuzzy logic were used for the parameterization of factors. Subsequently, a survey was applied to specify the gradation of individual factors with regard to their impact on productivity. The paper as a whole presents a mathematical algorithm, the practical application of which was presented too.

Palabras clave

  • algorithm
  • labour productivity
  • construction workers
access type Acceso abierto

Application of Unmanned Aerial Vehicles for Revising Dispersion of Time of Key Undertakings

Publicado en línea: 26 May 2020
Páginas: 163 - 170

Resumen

Abstract

The paper summarizes the concept of using unmanned aerial systems for construction work monitoring. Mobile drones can be used for determining the current stage of a given subtask in a complex construction project. Such control allows more adequate determination of the completion time of a given task, leading to more effective project schedule management.

Palabras clave

  • drones
  • construction works
  • project
access type Acceso abierto

The Idea of Graphic Profiles for Supporting a Choice of Material and Technological Solution

Publicado en línea: 26 May 2020
Páginas: 171 - 178

Resumen

Abstract

When constructing buildings and building structures, we must often solve dilemmas regarding the implementation of specific technologies and materials. Depending on the planned use of a building, its functions and the expectations of its future users, some solutions may be superior to others. Because of a high number of factors that weigh on the final decision, it is necessary to employ efficient decision-support tools. Having analysed such a cases, the author has developed her own approach based on a graphic template of an investment project, which is compared to the profiles of assessed variants. The article presents the approach using an example of constructing a production floor building, where the ambient conditions will be harsh due to the planned production profile. The analysis included construction variants with a roof supported by one of the three types of girders: wooden, steel and prestressed concrete ones.

Palabras clave

  • building materials
  • investment project variants
  • multi-criteria methods
  • graphic method
access type Acceso abierto

Microstructure and Properties of Sintered Metal Matrix Composites Reinforced with SiC Particles

Publicado en línea: 26 May 2020
Páginas: 179 - 190

Resumen

Abstract

Based on the prealloyed and diffusion bonded powders (Distaloy SA and Distaloy SE) different metal matrix composites reinforced with SiC particles were produced by the conventional powder metallurgy technology and the effect of varied amounts of SiC particles on microstructure evaluation and selected properties were investigated. It was stated that the mass fraction of SiC has a great effect on the density, porosity, shrinkage, hardness and wear resistance of studied composites. In the case of both Distaloy SA and Distaloy SE matrix materials, the optimum SiC content is 4 wt. % due to the highest wear resistance and hardness of sintered composite.

Palabras clave

  • metal matrix composites
  • SiC particles
  • Distaloy SA
  • Distaloy SE
  • sintering
  • density
  • hardness
  • wear resistance
  • microstructure
access type Acceso abierto

The Performance of the Rushton Turbine Eccentrically Positioned in a Mixing Vessel. Part I: The Qualitative CFD Analysis

Publicado en línea: 26 May 2020
Páginas: 191 - 196

Resumen

Abstract

A qualitative analysis of a liquid flow generated by a Rushton turbine eccentrically located in an unbaffled mixing vessel is presented in this paper. On the basis of CFD simulations the influence of the impeller position in the vessel on the flow pattern, velocity distributions and turbulence parameters are examined. Data are presented in visualisations and distribution maps created with various flow visualisation criterions. The results of this work can be used for the design and optimisation of mixing equipment applied in the industry.

Palabras clave

  • mixing
  • Rushton turbine
  • impeller eccentricity
  • flow circulation
  • CFD simulations
access type Acceso abierto

Determination of Initial Configuration of Mechanism of an Instrument for Measuring the Translation and Rotation of a Steered Wheel

Publicado en línea: 26 May 2020
Páginas: 197 - 207

Resumen

Abstract

This paper concerns the determination of the initial configuration of a mechanism of a prototypical instrument for measuring the translation and rotation of a steered wheel. It covers the determination of coordinates of characteristic points of the mechanism. They were measured using a ROMER measuring arm. In the paper the methodology of measurements is discussed, and in addition the results obtained are presented and their analysis conducted.

Palabras clave

  • car
  • steered wheel
  • prototypical measuring instrument
  • coordinate measurements
  • ROMER measuring arm
access type Acceso abierto

The use of Waste Heat from Flue Gas in the System of Regeneration of Steam Boiler Supply Water

Publicado en línea: 26 May 2020
Páginas: 209 - 217

Resumen

Abstract

This study presents an analysis of the process of the use of waste heat from flue gas for the purposes of heating water in the regeneration system of a steam power unit fuelled with brown coal with a power of 900 MWe. Preparation of flue gas and its initial moistening (increasing the dew point temperature) followed by cooling (condensation of the moisture contained in the flue gas) can ensure intensive heat exchange in the process of heat recovery. Replacing a first regeneration exchanger with the heat recovered from flue gas allows for an increase in steam power unit efficiency by 0.22% and limitation of CO2 emissions by 22,810 t/year, while reducing the fuel demand by 26,727 tonnes per annum. Depending on the prices of CO2 emissions permits and prices of brown coal, the proposed heat recovery allows for saving from €500,000 to €1,000,000 per year.

Palabras clave

  • waste heat
  • regeneration system
  • steam power unit
access type Acceso abierto

Software for Calculations of the Higgs Boson Lineshape in Future Lepton Colliders

Publicado en línea: 26 May 2020
Páginas: 219 - 228

Resumen

Abstract

Simple software for Monte Carlo (MC) calculation of the Higgs boson lineshape and its beam broadening effect due to the beam energy dispersion is described. The software is based on the FOAM [1, 2] adaptive MC integrator from ROOT library [3]. This software enables the reproduction of the results presented in publication [4] and the tests with different parameters for the lineshapes and QED correction factors. A parallel version of the software based on MPI [5] is also described.

Palabras clave

  • QCD
  • the Higgs boson cross section
  • energy scan
  • Monte Carlo methods
  • FOAM
  • machine energy spread
  • initial state radiation
20 Artículos
access type Acceso abierto

A Comparative Analysis of the Index Assessment of Church Acoustics using RASTI and STI

Publicado en línea: 26 May 2020
Páginas: 5 - 19

Resumen

Abstract

The article presents modified global assessment indices, developed in previous studies, for measuring the acoustic quality of Roman Catholic churches: the four-parameter Gap index and the Gi index based on five acoustic parameters. The replacement of RASTI, previously used in the acoustic assessment of churches, with STI has broadened the scope of church assessment and contributed to an improvement in the accuracy of the proposed method. Verification of new calculation procedures was performed on the 12 churches included in the calculation model and, additionally, on another church.

Palabras clave

  • church acoustics
  • index method
  • acoustic quality
access type Acceso abierto

Representation of Architectural Idea and Interpretation as Part of the Protection of Cultural Heritage

Publicado en línea: 26 May 2020
Páginas: 21 - 30

Resumen

Abstract

Architecture and urban planning, classified as technical disciplines of science, in their records of creative works, also maintain representations of architectural ideas in the form of drawings, sketches or paintings. Ancillary to national heritage collections, they are an extensive source of information, which links the autonomous vision of the creator with the form outline, thus, creating an external context of such a form. Original architectural notations are part of the documentation of designs that were later executed and those that failed to be executed at all; furthermore, they confirm the high quality of expertise and the individual approach typical of leading professionals in the field across the world. The inspiration drawn from the 20th and 21st century facilities, translated into the language of artistic expression, proves the interdisciplinarity of the architectural profession and its communicative and educational assets shall be subject to particular protection and shall be displayed in order to elevate the rank of their meaning in the design process as well as in the collection of national, cultural heritage.

Palabras clave

  • representation – document
  • artistic value
  • cognitive value
access type Acceso abierto

Chemical and Thermal Methods for Removing Ammonia from Fly Ashes

Publicado en línea: 26 May 2020
Páginas: 31 - 50

Resumen

Abstract

The presence of ammonia in ashes (i.e. ammonia slip) is a direct consequence of the methods used for denitrification – selective catalytic and non-catalytic reduction (SCR, SNCR). The excess unreacted ammonia used in both of these methods passes as a constituent to ash, impairing its properties, and thus affects the quality of the commercial product. The summary of the available methods for removing NH3 from fly ashes is presented. Both chemical and thermal methods of removing NH3are described. The results of the chemical methods depend on the kind of additional reagents used and composition of fly ashes. Thermal methods seem to be simpler and easier to use, but they are used mainly on the smaller scale.

Palabras clave

  • flyash
  • deammonisation
access type Acceso abierto

Neuro-Fuzzy Predictions of Construction Site Completion Dates

Publicado en línea: 26 May 2020
Páginas: 51 - 58

Resumen

Abstract

The results from two types of multi-layer perceptron artificial neural networks (Matlab R2015a was used) were compared. The first one, with only one neuron in an output layer having the value of delay in completion date of building site. The output layer of the second artificial neural network is created by three neurons. These three values represent the same delay, but in a form of three values of membership functions to fuzzy sets. In order to evaluate the accuracy of predictions, the mean squared error was used. It was necessary to find the best method of defuzzyfication predicted delays to compare the results from these two, aforementioned artificial neural networks. The level of prediction accuracy measured by mean squared error was discussed, too.

Palabras clave

  • MLP artificial neural networks
  • fuzzy sets
  • delays in completion dates
access type Acceso abierto

Property Valuation using Hedonic Price Method – Procedure and its Application

Publicado en línea: 26 May 2020
Páginas: 59 - 70

Resumen

Abstract

This paper discusses one of the property valuation methods, i.e. property valuation using the hedonic price method, which makes use of a classical linear regression model. The study characterises the calculation procedure of the selected method and indicates the fields of application of the hedonic approach in the construction sector. The operation of the hedonic price method is presented based on a valuation of flats in Lublin.

Palabras clave

  • property
  • property valuation
  • hedonic price method
  • classical linear regression model
  • hedonic regression
access type Acceso abierto

Dynamic Response of a Steel Pipeline with Bolted Connections to a Mining Shock Obtained with the Submodeling Technique

Publicado en línea: 26 May 2020
Páginas: 71 - 83

Resumen

Abstract

In this paper, the dynamic response of an overground steel pipeline to a real mining shock is presented. The submodeling method was used in the calculation. Firstly, time history analysis of a simplified beam model of the pipeline (a global model) was conducted. Secondly, the 3D model of a part of the structure over the support was created (a submodel). The submodeling analysis allowed obtaining stress distribution in the bolted connection of the pipeline segments.

Palabras clave

  • pipeline
  • dynamic response
  • mining shock
  • submodeling
access type Acceso abierto

Evaluation of the Technical Condition of the “Fryderyk” Adit in Tarnowskie Góry for the Purpose of Eventual Revitalization

Publicado en línea: 26 May 2020
Páginas: 85 - 99

Resumen

Abstract

The “Fryderyk” adit (renamed ‘Kościuszko’ after World War II) is the last adit built in the area of Tarnowskie Góry, and was supposed to provide drainage for the area of exploitation of the “Fryderyk” mine. After the shutdown of the mine, the adit gained an important role in the water management of the area. The water from nearby sources flows into the river Drama through the adit. The long period of the adit’s existence and the processes occurring in its area have caused a progressive process of support degradation, which increases the danger of a loss of stability and a collapse of the roof. Allowing the collapse of the adit’s roof may cause surface depressions. The article presents the research results that show an evaluation of the technical condition and safety degree of the support for future failure-free usage. A range of activities that are meant to stop the natural degradation of the end section of the adit has also been suggested.

Palabras clave

  • mining monuments
  • support
  • heading stability
  • surface deformation
access type Acceso abierto

Maintenance of Apartment Buildings and Their Measurable Deterioration

Publicado en línea: 26 May 2020
Páginas: 101 - 107

Resumen

Abstract

Apartment buildings constructed prior to the First World War are important examples of Polish buildings with regard to their historical significance – the technical maintenance of such buildings remains challenging. The results of the work refer to the general population, estimated for 600 objects, that compose of about 20% of municipal downtown apartment buildings in Wrocław. The purpose of the research was to identify an influence of widely considered maintenance of apartment houses on a degree and intensity of their elements’. The goal of this research has been achieved through the analysis of symptoms reflecting the decline of the inspected elements’ exploitation values, that is identification of mechanics of arising their defects. The calculated quantitative data can be used as the basis for identifying the structure of the building companies which are responsible for housing maintenance and repair.

Palabras clave

  • apartment buildings
  • maintenance
  • deterioration
  • technical wear
access type Acceso abierto

Analysis of Type of Construction Projects in Tender Formula “Design and Build”

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

Resumen

Abstract

The construction undertakings are being realized within two basic formulas:

▶ Design and separately execution of works – (“P”) + (“B”),

▶ Design and built – (“P+B”) otherwise called as “design and execution of works” („Z i W”).

The project realization procedure depends on the kind of undertaking and resources of the contracting authority. The choice of formula has an influence on the undertaking preparation as well as on the choice of executor and project realization. The article shows the results of research and defines the percent participation of the individual type of construction undertakings in “design and execution of work” formula that were realized in Poland in the years 2010–2016. “Design and execution of work” formula is used rarely in public procurements. The above-mentioned is confirmed by nation-wide statistic data and statistic data for the Kujawsko-Pomorskie and Warmińsko-Mazurskie provinces.

Palabras clave

  • public procurements
  • “design and build” formula
  • tendering mode
  • contracting authority
  • statistic data
access type Acceso abierto

Optimal Design of Structural Elements as a Control Theory Problem

Publicado en línea: 26 May 2020
Páginas: 119 - 134

Resumen

Abstract

In the paper an application of the maximum principle to designing a cross section of a still frame under several loading schemes is presented. The optimal height of the web under minimum volume of still as a cost function is determined. In particular the implicit and explicit conditions of state variables at characteristic points of axis of symmetry under different loading schemes are presented.

Palabras clave

  • optimal control
  • maximum principle
access type Acceso abierto

Potential Reasons for Works Delays Resulting From the Provisions of the Agreement

Publicado en línea: 26 May 2020
Páginas: 135 - 143

Resumen

Abstract

The course of the construction process in time is shaped by a variety of factors, which, in effect, may become the reason for delays in project completion. The paper presents the outcome of research performed with Polish building works contractors. One of the aims was to try to identify the potential reasons for delays in construction works, which result from the provisions of the agreement. Early recognition and an assessment of possible risks may assist the contractor’s attempts to eliminate them or to lessen the scale of delays in the project implementation.

Palabras clave

  • delays
  • construction works
  • factor identification
access type Acceso abierto

Prediction of Changes in the Performance Characteristics of a Building

Publicado en línea: 26 May 2020
Páginas: 145 - 151

Resumen

Abstract

Over the course of their use, building structures are subject to constant destructive processes, which can take various courses. Over time, performance characteristics deteriorate, and can be partially restored as a result of repair works. The article presents a proposal for the prediction of changes in the performance characteristics of a building based on the adaptation of principles applied in predicting the operational reliability of technical objects.

Palabras clave

  • degree of wear
  • prediction
  • life distribution
access type Acceso abierto

The Algorithm for the Evaluation of Construction Workers’ Labour Productivity

Publicado en línea: 26 May 2020
Páginas: 153 - 161

Resumen

Abstract

The paper presents an algorithm that allows to calculate the potential productivity of construction workers, including the factors that influence them. Its development involves one of the classifications of factors. In the next step, the elements of fuzzy logic were used for the parameterization of factors. Subsequently, a survey was applied to specify the gradation of individual factors with regard to their impact on productivity. The paper as a whole presents a mathematical algorithm, the practical application of which was presented too.

Palabras clave

  • algorithm
  • labour productivity
  • construction workers
access type Acceso abierto

Application of Unmanned Aerial Vehicles for Revising Dispersion of Time of Key Undertakings

Publicado en línea: 26 May 2020
Páginas: 163 - 170

Resumen

Abstract

The paper summarizes the concept of using unmanned aerial systems for construction work monitoring. Mobile drones can be used for determining the current stage of a given subtask in a complex construction project. Such control allows more adequate determination of the completion time of a given task, leading to more effective project schedule management.

Palabras clave

  • drones
  • construction works
  • project
access type Acceso abierto

The Idea of Graphic Profiles for Supporting a Choice of Material and Technological Solution

Publicado en línea: 26 May 2020
Páginas: 171 - 178

Resumen

Abstract

When constructing buildings and building structures, we must often solve dilemmas regarding the implementation of specific technologies and materials. Depending on the planned use of a building, its functions and the expectations of its future users, some solutions may be superior to others. Because of a high number of factors that weigh on the final decision, it is necessary to employ efficient decision-support tools. Having analysed such a cases, the author has developed her own approach based on a graphic template of an investment project, which is compared to the profiles of assessed variants. The article presents the approach using an example of constructing a production floor building, where the ambient conditions will be harsh due to the planned production profile. The analysis included construction variants with a roof supported by one of the three types of girders: wooden, steel and prestressed concrete ones.

Palabras clave

  • building materials
  • investment project variants
  • multi-criteria methods
  • graphic method
access type Acceso abierto

Microstructure and Properties of Sintered Metal Matrix Composites Reinforced with SiC Particles

Publicado en línea: 26 May 2020
Páginas: 179 - 190

Resumen

Abstract

Based on the prealloyed and diffusion bonded powders (Distaloy SA and Distaloy SE) different metal matrix composites reinforced with SiC particles were produced by the conventional powder metallurgy technology and the effect of varied amounts of SiC particles on microstructure evaluation and selected properties were investigated. It was stated that the mass fraction of SiC has a great effect on the density, porosity, shrinkage, hardness and wear resistance of studied composites. In the case of both Distaloy SA and Distaloy SE matrix materials, the optimum SiC content is 4 wt. % due to the highest wear resistance and hardness of sintered composite.

Palabras clave

  • metal matrix composites
  • SiC particles
  • Distaloy SA
  • Distaloy SE
  • sintering
  • density
  • hardness
  • wear resistance
  • microstructure
access type Acceso abierto

The Performance of the Rushton Turbine Eccentrically Positioned in a Mixing Vessel. Part I: The Qualitative CFD Analysis

Publicado en línea: 26 May 2020
Páginas: 191 - 196

Resumen

Abstract

A qualitative analysis of a liquid flow generated by a Rushton turbine eccentrically located in an unbaffled mixing vessel is presented in this paper. On the basis of CFD simulations the influence of the impeller position in the vessel on the flow pattern, velocity distributions and turbulence parameters are examined. Data are presented in visualisations and distribution maps created with various flow visualisation criterions. The results of this work can be used for the design and optimisation of mixing equipment applied in the industry.

Palabras clave

  • mixing
  • Rushton turbine
  • impeller eccentricity
  • flow circulation
  • CFD simulations
access type Acceso abierto

Determination of Initial Configuration of Mechanism of an Instrument for Measuring the Translation and Rotation of a Steered Wheel

Publicado en línea: 26 May 2020
Páginas: 197 - 207

Resumen

Abstract

This paper concerns the determination of the initial configuration of a mechanism of a prototypical instrument for measuring the translation and rotation of a steered wheel. It covers the determination of coordinates of characteristic points of the mechanism. They were measured using a ROMER measuring arm. In the paper the methodology of measurements is discussed, and in addition the results obtained are presented and their analysis conducted.

Palabras clave

  • car
  • steered wheel
  • prototypical measuring instrument
  • coordinate measurements
  • ROMER measuring arm
access type Acceso abierto

The use of Waste Heat from Flue Gas in the System of Regeneration of Steam Boiler Supply Water

Publicado en línea: 26 May 2020
Páginas: 209 - 217

Resumen

Abstract

This study presents an analysis of the process of the use of waste heat from flue gas for the purposes of heating water in the regeneration system of a steam power unit fuelled with brown coal with a power of 900 MWe. Preparation of flue gas and its initial moistening (increasing the dew point temperature) followed by cooling (condensation of the moisture contained in the flue gas) can ensure intensive heat exchange in the process of heat recovery. Replacing a first regeneration exchanger with the heat recovered from flue gas allows for an increase in steam power unit efficiency by 0.22% and limitation of CO2 emissions by 22,810 t/year, while reducing the fuel demand by 26,727 tonnes per annum. Depending on the prices of CO2 emissions permits and prices of brown coal, the proposed heat recovery allows for saving from €500,000 to €1,000,000 per year.

Palabras clave

  • waste heat
  • regeneration system
  • steam power unit
access type Acceso abierto

Software for Calculations of the Higgs Boson Lineshape in Future Lepton Colliders

Publicado en línea: 26 May 2020
Páginas: 219 - 228

Resumen

Abstract

Simple software for Monte Carlo (MC) calculation of the Higgs boson lineshape and its beam broadening effect due to the beam energy dispersion is described. The software is based on the FOAM [1, 2] adaptive MC integrator from ROOT library [3]. This software enables the reproduction of the results presented in publication [4] and the tests with different parameters for the lineshapes and QED correction factors. A parallel version of the software based on MPI [5] is also described.

Palabras clave

  • QCD
  • the Higgs boson cross section
  • energy scan
  • Monte Carlo methods
  • FOAM
  • machine energy spread
  • initial state radiation

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