Volume 114 (2017): Issue 6 (June 2017)

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 MW_e. 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.

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.