The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper proposes a comprehensive classification of test methods for the diagnosis of concrete structures. The main focus is on the ranges of suitability of the particular methods and techniques for assessing the durability of structures, depending on the principal degradation mechanisms and their effects on this durability. The survey covers non-destructive testing (NDT) methods, which do not in...
Damage and defects observed in concrete elements, such as a network of microcracks, popouts and eflorrescence can be caused by a variety of deleterious processes. The causes can include mechanical (overloading), physical (freeze-thaw cycle) or chemical exposure (sulphate corrosion, alkali-aggregate reaction). This paper analyses distress due to alkali-silica reaction, detected in selected concrete...
The paper presents experimental and numerical validation of the combustion process of coal and flour dust dispersed in a spherical chamber of 20 cubic decimetres volume. The aim of the study is to validate the numerical simulation results in relation to the experimental data obtained on the test stand. To perform the numerical simulations, a Computational Fluid Dynamics code FLUENT was used. Geometry...
This paper presents the basic information about the use of air curtains in fire safety, as a barrier for heat and smoke. The mathematical model of an air curtain presented allows to estimate the velocity of air in various points of space, including the velocity of air from an angled air curtain. Presented equations show how various parameters influence the performance of an air curtain, thus allowing...
A mathematical-physical model of a supersonic missile was built, taking into account the mass and inertia properties. The model was implemented in the MathCAD14 simulation program. A numerical analysis of the missile ballistics was conducted and basic parameters were determined: range, altitude, velocity and acceleration, which enabled a test range program for manufactured missile models to be drawn...
In this paper a simple diagnostic system for a single IGBT open-circuit faults for a two level voltage inverter-fed field oriented controlled induction motor drive was presented. A fault diagnostic procedure is carried out by utilizing an analysis of a stator current vector trajectory in α-β coordinates. An extraction of the failure information is based on monitoring of an angle between the stator...
This paper focuses on evaluation of two laboratory-based methods of compaction of foamed bitumen and bitumen emulsion mixes: impact compaction with a Marshall hammer and static compaction using a hydraulic press. The investigated compaction methods were assessed in terms of their impact on the physical and mechanical properties of produced laboratory specimens, including: air void content, indirect...
The paper considers a particular group of rule interestingness measures, called Bayesian confirmation measures, which have become the subject of numerous, but often exclusively theoretical studies. To assist and enhance their analysis in real-life situations, where time constraints may impede conducting such time consuming procedures, a visual technique has been introduced and described in this paper...
Many steel riveted bridges have been built in Poland since 1950 and they have not reached their design working lives yet. Nevertheless, a number of fatigue damages are found, especially with structural joints. Moreover, in the past 25 years the traffic on the Polish road network has increased significantly leading to the increasing number of heavy vehicles in the traffic flows. This may affect the...
The paper is concerned with the metallization of ceramic materials using the friction-welding method in which the mechanism of the formation of a joint involves the kinetic energy of friction. The friction energy is directly transformed into heat and delivered in a specified amount precisely to the joint being formed between the metallic layer and the substrate material. The paper describes the ceramic...
The aim of the paper was to present the author’s novel approach to the problem of the influence of concrete shrinkage on the static-strength performance of reinforced structures. The problem of concrete shrinkage has been known in concrete technology for years, mainly in the theoretical and experimental aspects. However, there are few works in which the effect of concrete shrinkage in real reinforced...
The paper discusses issues related to monitoring quality and pressure of water transmitted using water supply networks. Special attention was paid to methods of determining location of measuring points, which to a large extent influence effectiveness of the monitoring system. The purpose of the paper is to present authors’ own method of determining location of points of measuring quality and pressure...
The paper presents problems related to the numerical modeling of profiled steel sheets used as self-supporting arch structures for roof covering. The rules of preparing and full analysis of a set of numerical models of these elements with a different level of complexity are given. The models are evaluated by comparing numerical results with the results of extended experimental tests performed by 3D...
The paper presents the experimental results of fabrication and characterization of ceramic- elastomer composites. They were obtained using pressure infiltration of porous ceramics by elastomer As a result the composites in which two phases are interpenetrating three-dimensionally and topologically throughout the microstructure were obtained. In order to enhance mechanical properties of preforms a...
FIR filters are often applied, as they possess many advantages, including linear-phase response and well elaborated design methods. However, group delay introduced by FIR filters is usually large. The reduction of group delay can be obtained by restriction of the linear phase requirement only to the passband. One of the problems that appear while designing FIR filters with a prescribed value of group...
This paper focuses on examinations of asphalt-cement mixtures (ACM). This is a recycled material which can be used in road pavement layers. In the article stiffness modulus tests and fatigue tests of asphalt-cement mixtures were shown. The authors decided to lead research on fatigue durability of asphalt-cement mixtures to set fatigue characteristics of these materials. So far in research or other...
Alkali-aggregate reaction is an expansive chemical reaction between the alkalis present in cement paste and minerals contained in aggregates. Mineral admixtures can mitigate the detrimental processes caused by this reaction. One of the minerals that reduce the effects of the alkali-aggregate reaction is natural zeolite. This study attempts to explain the process that takes place in the zone surrounding...
Adhesion in repair systems is one of the most important factors affecting their durability. Elaboration of a reliable nondestructive test method to perform an adhesion mapping is one of the most important tasks. A majority of NDT methods applicable for the assessment of concrete structures are based on the propagation of various types of stress waves. In this paper, the influence of the repair material...
The competence-based learning-teaching process is a significant approach to the didactical process organization. In this paper the mathematical model of the competence-based learning-teaching process is proposed. The model integrates three models: a knowledge representation model (based on the ontological approach), a motivation model (as a behavioral-incentive model) and a servicing model (in a form...
The paper refers to the approach used in science, specifically in building materials engineering, assuming the possibility of material modeling, including modeling of the technical characteristics of building materials of various compositions as well as modeling phenomena/processes that occur during the use of materials and structures made from them. The authors analyze the merits of the approach...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.