Search
Filters
total: 384
filtered: 288
-
Catalog
Chosen catalog filters
Search results for: ZMIANY W CZASIE
-
Operation evaluation method for marine turbine combustion engines in terms of energetics
PublicationAn evaluation proposal (quantitative determination) of an y combustion turbine engine operation has been presented , wherein the impact energy occurs at a given time due to Energy conversion. The fact has been taken into account that in this type of internal combustion engines the energy conversion occurs first in the combustion chambers and in the spaces between the blade of the turbine engine. It was assumed that in the combustion...
-
Problems of collisions between adjacent steel structures under earthquake excitation
PublicationNowadays, the high level of urbanization forces the designers to design closely-separated structures and to take into account many factors influencing the response of these structures, which may collide due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as numerical and experimental investigations have confirmed that the interactions between structures may lead to significant...
-
IDENTIFICATION OF DAMAGES OF TRIBOLOGICAL ASSOCIATIONS IN CRANKSHAFT AND PISTON SYSTEMS OF TWO-STROKE INTERNAL COMBUSTION ENGINES USED AS MAIN PROPULSION IN SEA-GOING VESSELS AND PROPOSAL OF PROBABILISTIC DESCRIPTION OF LOADS AS CAUSES OF THESE DAMAGES
PublicationThe article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of...
-
The Impact of Micro-Sources on Voltage Distortions in a Power Grid
PublicationThe increase in the number of photovoltaic (PV) systems integrated with low voltage (LV) grids has led to a great need to analyse the impact of these systems on the quality of electricity and the reliability of its supply. This paper presents and compares the energy quality requirements imposed by various countries on photovoltaic plants. Then, based on real object tests and simulation in DIgSILENT PowerFactory, the impact has...
-
A method of nonlinearities of transformer no-load characteristic modelling
PublicationA way in which changes of the no-load characteristic are taken into account in the mathematical model of the transformer is presented. Changes of saturation within core of transformer are presented as a combined non-linear flux curve. Analysis of magnetization of the transformer core and simulation of no-load state for distribution transformer of 30 kVA power rating and 15.75/0.4 kV/kV (especially supplying VLV) transformation...
-
SAMPLE-AND-HOLDING METHOD FOR GAS SENSING APPLIED FOR RESISTANCE GAS SENSORS
PublicationThe DC resistance of a Taguchi gas sensor is influenced by the ambient gas. To improve the selectivity and sensitivity of a sensor the fluctuation enhanced sensing (FES) was used. The paper proposes a novel methodology of utilizing FES technique that sample composition of an ambient atmosphere and hold it for further processing (sample-and-holding technique). The method uses the heated gas sensor to sample an ambient atmosphere...
-
CSR in Polish SMEs- from perception to infatuation. Examples of socially engaged firms from Pomeranian Region
PublicationDespite the increasing worldwide awareness of the importance of social issues in con-temporary business management, Polish small and medium-sized enterprises seem to re-main in the group of followers, certainly not leaders, of the corporate social responsibility (CSR) movement, and this despite important dissemination efforts by numerous institu-tions. The aim of this paper is to present the bumpy road to the (still incomplete)...
-
Development and tuning of irregular divide-and-conquer applications in DAMPVM/DAC
PublicationThis work presents implementations and tuning experiences with parallel irregular applications developed using the object oriented framework DAM-PVM/DAC. It is implemented on top of DAMPVM and provides automatic partitioning of irregular divide-and-conquer (DAC) applications at runtime and dynamic mapping to processors taking into account their speeds and even loads by other user processes. New implementations of parallel applications...
-
Discrete-time estimation of nonlinear continuous-time stochastic systems
PublicationIn this paper we consider the problem of state estimation of a dynamic system whose evolution is described by a nonlinear continuous-time stochastic model. We also assume that the system is observed by a sensor in discrete-time moments. To perform state estimation using uncertain discrete-time data, the system model needs to be discretized. We compare two methods of discretization. The first method uses the classical forward Euler...
-
Parameter and delay estimation of linear continuous-time systems
PublicationIn this paper the problem of on-line identification of non-stationary delay systems is considered. Dynamics of supervised industrial processes is described by ordinary differential equations. Discrete-time mechanization of their continuous-time representations is based on dedicated finite-horizon integrating filters. Least-squares and instrumental variable procedures implemented in recursive forms are applied for simultaneous identification...
-
Electricity Supplier Switching Process in Poland – a Process Based on the General Distribution Agreement
PublicationPoland, as a Member State of the European Union, is committed to respect the common rules on the electricity market, among other things. One of the most important examples of these regulations is the perception of energy as a commodity subject to competitive market mechanisms. Competitive processes introduced in the national electricity market enable energy consumers, i.a., choice of electricity supplier under the TPA formula....
-
Modified dynamic time warping method applied to handwritten signature authenticity verification
PublicationA signature verification system based on static features and time-domain functions of signals obtained using a tablet has been presented in the paper. The signature verification method, based mainly on dynamic time warping coupled with some signature image features, has been described. The FRR measures reflecting the method’s efficiency have been evaluated for verification attempts performed directly after obtaining model signatures...
-
Identification of continuous systems - Practical issues of insensitivity to perturbations
PublicationIn this paper the issue of continuous systems estimation, insensitive to certain perturbations, is discussed. Such an approach has rational advantages, especially when robust schemes are used to assist a target system responsible for industrial diagnostics. This requires that estimated model parameters are generated on-line, and their values are reliable and to a great extent accurate. Practical hints are suggested to challenge...
-
Identification of Continuous Systems - Practical Issues of Insensitivity to Perturbations
PublicationIn this paper the issue of continuous systems estimation, insensitive to certain perturbations, is discussed. Such an approach has rational advantages, especially when robust schemes are used to assist a target system responsible for industrial diagnostics. This requires that estimated model parameters are generated on-line, and their values are reliable and to a great extent accurate. Practical hints are suggested to challenge...
-
Lamb wave-based monitoring of shear failure of an adhesive lap joint
PublicationThe paper presents a study on the elastic wave propagation in adhesive joints of steel plates subjected to tensile loading. A single lap joint was chosen for analysis because of its simplicity and plurality of applications. Experimental investigations consisted of the uniaxial extension of prepared specimens. Force and displacement values were recorded by a testing machine. Simultaneously, guided Lamb waves were excited and signals...
-
THE PANTOGRAPH AND ITS GEOMETRIC TRANSFORMATIONS - A FORMER POPULAR TOOL FOR COPYING AND SCALING
PublicationDevelopment of digital technology has resulted in significant transformations of designer workshops. Computer applications replaced the previously existing tools and methods for drawing up of projects. Professional, sophisticated drawing instruments and tools for manual plotting, as well as basic drawing aids, have gradually fallen into oblivion and become relicts of a bygone era - the objects of collectors' interest. Gdansk University...
-
PROBLEMS OF COLLISIONS BETWEEN ADJACENT STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublicationNowadays, the high level of urbanization forces the engineers to design closely-separated structures and to take into account many factors influencing their response, including collisions between them due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as experimental and numerical investigations have confirmed that interactions...
-
Co-Living or a “Sandpit” for Future Entrepreneurs. First Experience from Poland.
PublicationNowadays, the Western world seems saturated with the myriad of enhancements for entrepreneurship development. Also, in Eastern European countries we observe a growing number of initiatives at different organizational levels, aiming at accompanying potential future entrepreneurs in their efforts. Meanwhile, there is one novelty, never before offered on the Polish market – the first co- -living space, launched in Gdañsk. Therefore,...
-
Variability of relationship between cities and nature in landscape architecture= Zmienność relacji miedzy miastem a naturą na przykładzie architektury krajobrazu miast
PublicationInterpreting and creating the relations between nature and city are the process of learning which is a subject of permanent conceptualization. It is characterized by the culutrality due to human nature and own ability to perceive oneself in the context of the relationship between own environmental and cultural nature. The way of interpreting the nature and providing it with different features affected significantly the development...
-
Four-state stochastic model of changes in the reliability states of a motor vehicle
PublicationThe properties of semi-Markov processes have been generally characterized and the applicability of the theory of such processes to the determining of the reliability of motor cars and other road vehicles has been explained. A formal description of the process of changes in the motor vehicle technical states considered as reliability states and a model of this process in the form of a one-dimensional stochastic process have been...
-
Sub-regional service centres in reality and regional planning in Poland = Podregionalne osrodki obsługi w sferze realnej i planowaniu regionalnym w Polsce
PublicationSub-regional centres are defined as towns where the services of the sub-regional level are concentrated. In Poland these are such services that can be located in several towns in a voivodeship (region), but not in every capital of a poviat (county). The transformation of civilization has influenced changes in Christaller’s model of settlement network, but re-gularities are still valid. Models derived from Christaller's Central...
-
Detection and time/frequency analysis of electric fields in the ground
PublicationThis paper sets out to detect and characterize electric fields in the ground (such as stray current fields) using a tandem time/frequency method of signal analysis. Results were obtained from investigations performed in the presence of a generated electric field with controlled variable characteristics, and in the presence of an electric field generated by a tramline. The analysis of measurement registers was performed using Short‐Time...
-
A CONCEPT OF DETERMINING THE RELATION BETWEEN LOAD AND WEAR OF TRIBOLOGICAL SYSTEMS OF SHIP MAIN SELF-IGNITION ENGINES BY USING PROBABILISTIC APPROACH PROBABILISTIC APPROACH
PublicationThis paper presents a proposal of simultaneous consideration of load and wear associated with it , of tribological systems of ship main engines (intended for ship propulsion) . Based on results of investigations it was assumed that both the load Q (i.e. a cause of wear ) and the wear Z (i.e. an effect of load occurrence) considered in a given time t(0 ≤ t ≤ t) are random variables Qt and Zt, respectively. There was characterized...
-
THE ARCHITECTURE OF DAYLIGHT IN THE DISCOURSE ABOUT THE AESTHETICS OF SUSTAINABILITY
PublicationThe need to create ecological and energy efficient architecture is evident today. In the contemporary discourse on architecture more and more attention is dedicated to the aesthetics that expresses the idea of sustainability. The article is a voice in this debate, concentrating on the architecture that features daylight. Solar light comes from the natural environment and brings some substantial benefits for the architectural space,...
-
Sundials of St Mary’s Church in Gdańsk / Zegary słoneczne kościoła pw. Wniebowzięcia Najświętszej Panny Marii w Gdańsku
PublicationThe paper presents contemporary research evidence of form, function and history of the sundials of St Mary’s Church in Gdańsk. The discussed sundials are located on the southern wall of the church transept. The sundial, which is believed to be made by Lorenzo Zachau in 1533, is placed on the west side of the western window, at the edge of the wall. The face of this sundial is separated by a horizontal line into two parts. The upper...
-
Thermoplastic elastomer filaments and their application In 3D printig
PublicationThe paper provides an overview on the materials used in the 3D printing technology (the Polish and foreign market) with a particular focus on flexible filaments and their possible application in the industry. There are described the techniques of 3D printing and modern filaments available on the market. There is observed the increase of interest in the production of products from filaments based on thermoplastic elastomers (TPE),...
-
Selected symmetrically substituted carbazoles: Investigation of anticancer activity and mechanisms of action at the cellular and molecular levels
PublicationDNA topoisomerases play a critical role as essential enzymes in controlling alterations in the topology of DNA. They achieve this by orchestrating the coordinated process of breaking and rejoining DNA strands, which is crucial for maintaining the proper structure of DNA during regular cellular development. The search for and development of new potential anticancer drugs is a challenging yet immensely important area of research...
-
In Search of Naval Beauty. Historical Study of Ship Architecture
PublicationDesigning ships is no mean achievement. In the old days, constructors focused on making their ships visually appealing, while paying scant regard to the living conditions of the crew. Such an approach reflected the state of the art in ship building at the time as well as the social order prevalent in those days. A breakthrough came no earlier than at the turn of the 19th / 20th centuries. The industrial revolution brought along...
-
Guided wave propagation in structures. Modelling, experimental studies and application to damage detection
PublicationCelem niniejszej pracy są eksperymentalne i numeryczne analizy propagacji prowadzonych fal sprężystych w stalowych konstrukcjach prętowych, belkowych, ramowych, tarczowych i płytowych. W szczególności praca poświęcona jest: (a) modelowaniu propagacji fal z uwzględnieniem zjawiska dyspersji; (b) budowie modeli obliczeniowych w formalizmie metody elementów spektralnych; (c) eksperymentalnej weryfikacji zaproponowanych modeli; (d)...
-
THE COST ANALYSIS OF CORROSION PROTECTION SOLUTIONS FOR STEEL COMPONENTS IN TERMS OF THE OBJECT LIFE CYCLE COST
PublicationSteel materials, due to their numerous advantages - high availability, easiness of processing and possibility of almost any shaping are commonly applied in construction for carrying out basic carrier systems and auxiliary structures. However, the major disadvantage of this material is its high corrosion susceptibility, which depends strictly on the local conditions of the facility and the applied type of corrosion protection system....
-
Historic centre of Gdańsk as a unique example of postwar socialist city creation = Historyczne śródmieście Gdańska jako unikalny przykład powojennej kreacji miasta socjalistycznego
PublicationThe historic centre of Gdańsk, totally destroyed towards the end of the Second World War, became an area of postwar creation of a socialist town. During over a dozen first years, three projects were prepared for implementation within its borders, first in the convention of reconstruction and rest simply as development, for three consecutive historic city complexes: The Main Town (1948), The Old Town (1955) and The Old Suburbs (1958),...
-
Testing Students’ Entrepreneurial Self-Efficacy as an Early Predictor of Entrepreneurial Activities. Evidence From the SEAS Project
PublicationOver the last forty years, since Bandura (1977) introduced the concept of self-efficacy, there have been a constantly growing number of research publications using this concept. Its early development resulted in the creation of a new construct of entrepreneurial self-efficacy (ESE) proposed for the first time by (Chen et al. 1998). Since then, many different groups of research concerning ESE have emerged - one of them is the study...
-
Analysis of catalitic reactors usefulness to reduce pollution generated by piston combustion engines with regard to ship main engines
PublicationThe article presents results which indicate that the use of catalytic reactors to reduce emissions of harmful compunds contained in the exhaust gas is important in the operation of vehicle motors operation. Efforts of the shipbuilding industry to reduce the toxicity of exhaust gas emitted by the main engines have been indicated and pointed to the desirability of the use of these catalysts in maritime transport. It has been pointed...
-
The future of the logistician education in Poland and Ukraine: comparative analysis of the student’s opinion
PublicationBackground: A professional future is the next logical step after a student completes their chosen degree course. More frequently, even during their studies, young people seek opportunities to participate in various conferences, training courses, internships, work placements, and to travel abroad, etc. All of this has one main goal - to increase the student's attractiveness as a potential employee on the labour market. Thus, it...
-
Features of load and wear of main propulsion devices on sea-going ships with piston combustion engines and their impact on changes in technical states of the systems
PublicationThe paper presents the specificity of operation of propulsion systems of seagoing ships which causes the need to control the load on them, especially on their engines called main engines. The characteristics of the load on the propulsion systems, especially on the main engines as well as on the shaft lines and propellers driven by the engines, along with the process of wear in tribological joints (sliding tribological systems)...
-
Digital Innovations and Smart Solutions for Society And Economy: Pros and Cons
PublicationRecent developments in artificial intelligence (AI) may involve significant potential threats to personal data privacy, national security, and social and economic stability. AI-based solutions are often promoted as “intelligent” or “smart” because they are autonomous in optimizing various processes. Be-cause they can modify their behavior without human supervision by analyzing data from the environ-ment, AI-based systems may be...
-
Movement perception with the use of a motorized delta armrest and virtual reality
PublicationIn this paper we present a combination of neuroscience experiments with the use of a parallel armrest robot to study the effects of temporal delays and spatial biases on the movement perception. A dedicated armrest to guide and manipulate the arm has been developed for these experiments. It is a three-degree-of-freedom Delta structure. In combination with a virtual reality application, the movement perception has been evaluated....
-
Uprawnienia budowlane wynikające z przepisów wykonawczych w latach 1928-2003.
PublicationPrzedstawiono opracowanie omawiające zmiany w zakresie uprawnień budowlanych. Zwrócono uwagę na szczególne problemy w tym powtarzające się anomalie.