Skocz do pozycji: 1.

Tytuł:

Implementation of mathematical model of thermal behavior of electronic components for lifetime estimation based on multi-level simulation

Autorzy:

Frivaldsky, M.
Pridala, M.
Drgona, P.

Powiązania:

https://bibliotekanauki.pl/articles/140808.pdf

Data publikacji:

2017

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

electrolytic capacitor
lifetime model
lifetime estimation
system-level simulation

Opis:

The main purpose of the paper is the proposal of multi-level simulation, suited for the evaluation of the lifetime of critical electronic devices (electrolytic capacitors). The aim of this issue is to imagine about the expected operation of complex and expensive power electronic systems, when the failure of the most critical component occurs. For that reason, various operational conditions and various physical influences must be considered (e.g. mechanical, humidity, electrical, heat stress), where nonlinearities are naturally introduced. Verification of the proposal is given, whereby the life-time estimation of an electrolytic capacitor operated in a DC-DC converter during various operational conditions is shown. At this point electrical and heat stress is considered for lifetime influence. First, the current state in the field of mathematical modeling of the lifetime for electrolytic capacitors, considering main phenomena is introduced. Next, individual sub-models for multi-level simulation purposes are developed, including a thermal simulation model and electrical simulation model. Several complexities of individual models are mutually compared in order to evaluate their accuracy and suitability for further use. Proper simulation tools have been mutually linked and data transfer was secured, in order to have the possibility of investigation of a lifetime depend on the changes of various variables.

Źródło:

Archives of Electrical Engineering; 2017, 66, 2; 339-350
1427-4221
2300-2506

Pojawia się w:

Archives of Electrical Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 2.

Tytuł:

Numerical investigation of creep behaviour of high-temperature steam turbine compone

Autorzy:

Banaszkiewicz, M.

Powiązania:

https://bibliotekanauki.pl/articles/175375.pdf

Data publikacji:

2012

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

creep
lifetime assessment
steam turbine

Opis:

The paper presents a model for creep basing on the so-called characteristic creep strain. It illustrates its application in computations of old steam turbines components. The presented model is a modification of the Norton model which relates the stress exponent to the creep rupture strength and current stress. Creep strain is a function of the above two quantities, i.e., rupture strength and current stress, and acharacteristic creep strain which is material constant for a given time and temperature. Computational examples regard the rotating and pressure components analysed using the finite element method.

Źródło:

Transactions of the Institute of Fluid-Flow Machinery; 2012, 124; 5-15
0079-3205

Pojawia się w:

Transactions of the Institute of Fluid-Flow Machinery

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 3.

Tytuł:

Methodology of threat autonomous assessment and forecasting the lifetime of the marine structure

Autorzy:

Murawski, L.

Powiązania:

https://bibliotekanauki.pl/articles/245864.pdf

Data publikacji:

2015

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

monitoring systems
non-destructive tests
ship structures lifetime prediction
damage identification
damage localization
lifetime forecasting

Opis:

Structural Health Monitoring (SHM) is a natural extension and supplement of Non-Distractive Tests (NDT). Structure assessment during periodical NDT tests is performed by highly trained human team. However, during long sea voyage, ship crew has no knowledge and possibility for detailed assessment and, what is more, has no knowledge lifetime predicting of ship structure. SHM systems should have good designed sensors types, distribution, and automatic recording unit. However, most important (and most difficult for designing) is autonomous and self-contained procedures for marine structures hazard assessment. In the paper, basic assumptions for numerical algorithms of signal processing, damage identification and localization, threat assessment and forecasting of structure lifetime are presented. SHM systems can be based on several different measurements techniques like: comparative vacuum monitoring, electromagnetic layer, Lamb waves, vibration based methods, acoustic emission, and fibre optics. Last three methods are most promising in the marine environment, according to the author experience. Global ship hull deformation should be monitored as quasi-continuous measurements. Optical Time-Domain Reflectometer method (OTDR) is planned by author for hull global deformation monitoring. Some local strain-stress concentration of hull structure and propulsion system bearings' reactions will be monitored by Fibre Bragg Grating (FBG) sensors. Both techniques (OTDR and FBG) have been shortly described in the paper.

Źródło:

Journal of KONES; 2015, 22, 2; 163-168
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 4.

Tytuł:

The method of estimating lifetimes of aircraft devices operating under ageing-attributable wearing conditions

Autorzy:

Ważny, M.

Powiązania:

https://bibliotekanauki.pl/articles/281271.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

reliability
lifetime
destructive processes
permissible condition

Opis:

The paper presents a probabilistic method of assessing lifetimes of selected structural components or assemblies of devices/systems affected by destructive processes that occur during aircraft operation. Reliability status of the device is evaluated by means of diagnostic or operational parameters. It is assumed that these devices (systems, assemblies) operate reliably if effects of wear and tear processes described by diagnostic parameters do not exceed boundary conditions/regimes. From the mathematical aspect, the method has been based on difference equations from which, when rearranged, a partial differential equation of the Fokker-Planck type is derived. A density function of the component wearing is a particular solution to this equation. With the density function of the component wearing applied, after suitable rearrangements, one can determine a density function of time for the exceeding the boundary condition. Now, with the density function of time of reaching the boundary condition found, and after rearrangement of this function, one receives dependences that can be applied to determine lifetime of the device given consideration. An example at the end of the paper illustrates how this method can be applied to analyse an airborne sighting system.

Źródło:

Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 981-990
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 5.

Tytuł:

Resonance production in heavy ion collisions

Autorzy:

Markert, Ch.

Powiązania:

https://bibliotekanauki.pl/articles/146392.pdf

Data publikacji:

2004

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

resonance
strangeness
baryon
freeze-out
lifetime
fireball

Opis:

Resonances and their decay products may interact strongly with the hadrons in the fireball medium from the time of chemical freeze-out until the system breaks up at kinetic freeze-out. In order to try to further our understanding of the evolution and expansion of this hot and dense medium we compare resonance particle yields and spectra from elementary p+p and heavy ion collisions.

Źródło:

Nukleonika; 2004, 49,suppl.2; 119-123
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 6.

Tytuł:

A model for service life control of selected device systems

Autorzy:

Zieja, M.
Ważny, M.

Powiązania:

https://bibliotekanauki.pl/articles/259281.pdf

Data publikacji:

2014

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

reliability
unreliability
durability
service lifetime
destructive processes

Opis:

This paper presents a way of determining distribution of limit state exceedence time by a diagnostic parameter which determines accuracy of maintaining zero state. For calculations it was assumed that the diagnostic parameter is deviation from nominal value (zero state). Change of deviation value occurs as a result of destructive processes which occur during service. For estimation of deviation increasing rate in probabilistic sense, was used a difference equation from which, after transformation, Fokker-Planck differential equation was obtained [4, 11]. A particular solution of the equation is deviation increasing rate density function which was used for determining exceedance probability of limit state. The so-determined probability was then used to determine density function of limit state exceedance time, by increasing deviation. Having at disposal the density function of limit state exceedance time one determined service life of a system of maladjustment. In the end, a numerical example based on operational data of selected aircraft [weapon] sights was presented. The elaborated method can be also applied to determining residual life of shipboard devices whose technical state is determined on the basis of analysis of values of diagnostic parameters.

Źródło:

Polish Maritime Research; 2014, 2; 45-49
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 7.

Tytuł:

A Survey of Multi-Objective Deployment in Wireless Sensor Networks

Autorzy:

Marks, M.

Powiązania:

https://bibliotekanauki.pl/articles/308483.pdf

Data publikacji:

2010

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

coverage
lifetime
placement
positioning
wireless sensor network

Opis:

The major challenge in designing wireless sensor networks (WSNs) is to find tradeoff between the desired and contrary requirements for the lifetime, coverage or cost while coping with the computation, energy and communication constraints. This paper examines the optimal placement of nodes for a WSN. It is impossible to consider the deployment of the nodes separately from WSNs applications. We highlight the properties of WSNs applications that determine the placement problem. We identify and enumerate the various objectives that should be considered. The paper provides an overview and concentrates on multi-objective strategies, their assumptions, optimization problem formulation and results.

Źródło:

Journal of Telecommunications and Information Technology; 2010, 3; 36-41
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 8.

Tytuł:

Fluorescence decay time distribution analysis of cyclic enkephalin analogues; Influence of solvent and Leu configuration in position 5 on conformation

Autorzy:

Malicka, Joanna
Ganzynkowicz, Robert
Groth, Małgorzata
Czaplewski, Cezary
Karolczak, Jerzy
Liwo, Adam
Wiczk, Wiesław

Powiązania:

https://bibliotekanauki.pl/articles/1044169.pdf

Data publikacji:

2001

Wydawca:

Polskie Towarzystwo Biochemiczne

Tematy:

lifetime distribution
fluorescence
energy transfer
conformation
enkephalin

Opis:

Lifetime distribution analysis were performed to study the influence of Leu configuration in position 5 on changes of the peptide chain of cyclic analogues of enkephalins containing a fluorescence donor and acceptor in different solvents. The configuration change of Leu5 in all the analogues of enkephalins studied which contain donor-acceptor pairs has no apparent influence on Trp lifetime distributions. In contrast, there is a significant solvent effect on the shape of lifetime distribution.

Źródło:

Acta Biochimica Polonica; 2001, 48, 1; 95-102
0001-527X

Pojawia się w:

Acta Biochimica Polonica

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 9.

Tytuł:

Methods and algorithms for evaluating unknown parameters of components reliability of complex technical systems

Autorzy:

Kołowrocki, K.
Soszyńska, J.

Powiązania:

https://bibliotekanauki.pl/articles/2069673.pdf

Data publikacji:

2009

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

reliability
safety
lifetime
distribution
estimation
maritime transport

Opis:

The paper objectives are to present the methods and tools useful in the statistical identifying the unknown parameters of the components reliability and safety of complex industrial systems and to apply them in the maritime industry. There are presented statistical methods of estimating the unknown intensities of departure from the reliability state subsets of the exponential distribution of the component lifetimes of the multistate systems operating in various operation states. The goodness-of-fit method applied to testing the hypotheses concerned with the exponential form of the multistate reliability function of the particular components of the complex technical system in variable operations conditions is suggested. An application of these tools to reliability characteristics of a ferry operating at the Baltic Sea waters is presented as well.

Źródło:

Journal of Polish Safety and Reliability Association; 2009, 2; 223--230
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 10.

Tytuł:

Low energy electrons in non-polar liquids

Autorzy:

Schmidt, W.
Illenberger, E.

Powiązania:

https://bibliotekanauki.pl/articles/148513.pdf

Data publikacji:

2003

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

electrons
energetics
kinetics
non-polar liquids
lifetime

Opis:

The properties of excess electrons in non-polar liquids have been studied for more than 30 years. Here, pertinent results are reviewed and discussed with respect to the possibility of studying electron-molecule interactions with low energy electrons in the liquid phase. Some new results on the estimate of the electron lifetime in the delocalized state in liquid hydrogen are presented.

Źródło:

Nukleonika; 2003, 48, 2; 75-82
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 11.

Tytuł:

Measurement the Thermal Profile of Steelmaking Ladle with Subsequent Evaluation the Reasons of Lining Damage

Autorzy:

Vlček, J.
Jančar, D.
Burda, J.
Klárová, M.
Velička, M.
Machovčák, P.

Powiązania:

https://bibliotekanauki.pl/articles/354815.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

ladle
refractory lining
temperature
enthalpy
ladle lifetime

Opis:

Based on the operational measurement, of which content was to determine ladle thermal profile, there were analysed causes of possible damage of lining in steel ladles by steel breakout through the ladle shell. There exists connection between thermal state of ladle lining during the operation and its lifetime. There were reached to the conclusion that the cause of failure in the lining of ladle is except for high temperature of bath, also wide interval of temperature change during the tap operation, in consequence with possible insufficient pre-heating of ladle, discontinuous operation of aggregate and damage of insulating lining layer, respectively deformation of ladles shell.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 1; 279-282
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 12.

Tytuł:

The Influence of the Base Material Parameters on Quantum and Photoconversion Efficiency of the Si Solar Cells

Autorzy:

Panek, P.

Powiązania:

https://bibliotekanauki.pl/articles/352268.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Czytelnia Czasopism PAN

Tematy:

silicon solar cell
dopant level
charge carrier lifetime

Opis:

The influence of a p-type Si with different resistivity, charge carrier lifetime and emitter dopant impurities concentration on the crystalline silicon solar cells parameters were analyzed and experimentally checked. The findings were determined by quasi-steady-state photoconductance, current-voltage and spectral response methods. The study was accompanied by solar device simulation using a numerical PC1D program. The highest photoconversion efficiency of 15.13 % was obtained for the moncrystalline (Cz-Si) solar cell with a base resistivity of 1.8 Ωcm and an effective charge carrier lifetime of 22.9 μs. The results clearly confirmed the importance concerning the dopant level in a Si base material in relation to open circuit voltage and short circuit current possible to obtain from the solar cell. Reduction of a base material resistivtiy leads to a lower value of an effective charge carrier lifetime and photoconversion efficiency both for Cz-Si and multicrystalline (mc-Si) solar cells. The experimental results and calculation showed, that in the case of a solar cell produced on the basis of crystalline silicon, the most important spectral range for an efficiency of a cell is covering a wavelength range of 587 ÷ 838 nm.

Źródło:

Archives of Metallurgy and Materials; 2016, 61, 4; 1889-1894
1733-3490

Pojawia się w:

Archives of Metallurgy and Materials

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 13.

Tytuł:

Application of the strain energy density parameter for estimation of multiaxial fatigue life of sintered steels with stress concentrators
Zastosowanie parametru gęstości energii odkształceń do oceny wieloosiowego zmęczenia stali spiekanych z koncentratorami naprężeń

Autorzy:

Łagoda, T.
Sonsino, C. M.
Ogonowski, P.

Powiązania:

https://bibliotekanauki.pl/articles/280271.pdf

Data publikacji:

2009

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

energy models
cyclic loading
fatigue lifetime
sintered steel

Opis:

This paper presents fatigue test results of a Fe-Cu sintered alloy (1.5% Cu) and three types of Fe-Cu-Ni sintered alloys (2% Cu, 2.5% Ni). Fe-Cu-Ni sintered alloys were produced under different compaction pressures and sintering temperatures. Round specimens with fillet notches were subjected to a constant amplitude pure bending, pure torsion and a combined in-phase and out-of-phase ( = 90.) bending with torsion. All results have been described by the criterion of the strain energy density parameter on the critical plane. It was assumed that the fatigue life is influenced by a linear combination of normal and strain energy density parameters with the coefficients that refer to the calculated plane. In particular, it allowed one to compute fatigue lives sufficiently comparable to the experimental ones.
W pracy przedstawiono rezultaty badań zmęczeniowych spieku Fe-Cu o zawartości 1.5% miedzi oraz trzech rodzajów spieku Fe-Cu-Ni o zawartości 2% miedzi i 2.5% niklu. Do badań zastosowano próbki okrągłe z koncentratorami naprężeń w postaci odsadzenia. Zakres badań obejmował stałoampitudowe zginanie, skręcanie oraz kombinacje proporcjonalnego i nieproporcjonalnego zginania ze skręcaniem. Wyniki badań eksperymentalnych zostały opisane przy zastosowaniu kryterium parametru energetycznego, opartego na koncepcji płaszczyzny krytycznej. Trwałość zmęczeniowa została wyznaczona na podstawie liniowej kombinacji parametru gęstości energii odkształceń normalnych oraz stycznych z pewnymi współczynnikami w przyjętej płaszczyźnie krytycznej. W większości przypadków otrzymano zadowalającą zgodność trwałości obliczeniowych z eksperymentalnymi.

Źródło:

Journal of Theoretical and Applied Mechanics; 2009, 47, 1; 161-175
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 14.

Tytuł:

The influence of hydrogen concentration on positron lifetime and electrical resistivity in vanadium-hydrogen systems

Autorzy:

Pietrzak, R.
Szatanik, R.

Powiązania:

https://bibliotekanauki.pl/articles/146289.pdf

Data publikacji:

2010

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

positron lifetime
resistivity
V-H system
annihilation parameters

Opis:

Positron lifetime spectra and electrical resistivity of the vanadium-hydrogen systems with hydrogen concentration ranging from 0 to 0.29 at.H/at.V have been investigated. The range of hydrogen concentrations under investigation included the single alfa phase and a mixture of the alfa and beta phases of V-H system. The registered positron lifetime spectra were analysed by decomposition into two components. A distinct change in the annihilation parameters has been found after exceeding the boundary concentration of hydrogen in vanadium corresponding to the phase transition alfa (alfa+ beta). Correlation of changes in the parameters of the positron lifetime spectrum and in the electrical resistivity resulting from the changes in hydrogen concentration, has been revealed.

Źródło:

Nukleonika; 2010, 55, 1; 35-39
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 15.

Tytuł:

Evaluation of the durability of selected LED lamps

Autorzy:

Zalesińska, Małgorzata
Zabłocka, Julita
Pawlak, Andrzej

Powiązania:

https://bibliotekanauki.pl/articles/135480.pdf

Data publikacji:

2020

Wydawca:

Akademia Morska w Szczecinie. Wydawnictwo AMSz

Tematy:

lifetime
LED lamps
non-directional LED lamps for household use
Ulbricht’s sphere
forecasting the luminous flux reduction
forecasted lifetime

Opis:

Luminous flux reduction during operation affects the operating lifetimes of LED lamps. Due to the very long lifetimes of LED sources, i.e. tens of thousands of hours, the lifetime declared by the manufacturer is most often determined by forecasting the luminous flux reduction. Lifetime forecasting is performed based on measuring the operating luminous flux reduction within a time frame of at least 6000 hours, every 1000 hours, followed by extrapolating the obtained results with a relevant exponential curve. This article presents the results of measurements of luminous flux changes taking place between 0 and 10,000 operating hours of several LED light sources. The obtained results were analyzed, and the lifetimes of the examined lamps were evaluated.

Źródło:

Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2020, 61 (133); 23-28
1733-8670
2392-0378

Pojawia się w:

Zeszyty Naukowe Akademii Morskiej w Szczecinie

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 16.

Tytuł:

Performance Evaluation of a Zone-based Three-level Heterogeneous Clustering Protocol for WSNs

Autorzy:

Rao, Sanapala Shanmukha
Shilpi
Kumar, Arvind

Powiązania:

https://bibliotekanauki.pl/articles/24200745.pdf

Data publikacji:

2023

Wydawca:

Instytut Łączności - Państwowy Instytut Badawczy

Tematy:

clustering
heterogeneous
network lifetime
stability period
zone-based WSN

Opis:

This paper proposes a zone-based three-level heterogeneous clustering protocol (ZB-TLHCP) for heterogeneous WSNs. In ZB-TLHCP, the sensor field/region is divided into zones where super, advance, and normal nodes are deployed uniformly and randomly. The performance of the proposed ZB-TLHCP system is compared with that of zonal-stable election protocol (Z-SEP), distributed energy efficient clustering (DEEC), and threshold-based DEEC (TDEEC) protocol by varying the number of super and advance nodes, their energy levels for the fixed sensor field, and the total number of nodes. Matlab simulation results revealed that the proposed ZB-TLHCP solution performed better than Z-SEP, DEEC, and TDEEC protocols, as it increased the instability period, prolonged the network's lifetime, and achieved higher throughput values.

Źródło:

Journal of Telecommunications and Information Technology; 2023, 3; 85--93
1509-4553
1899-8852

Pojawia się w:

Journal of Telecommunications and Information Technology

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 17.

Tytuł:

A method for estimating the probability distribution of the lifetime for new technical equipment based on expert judgement

Autorzy:

Andrzejczak, Karol
Bukowski, Lech

Powiązania:

https://bibliotekanauki.pl/articles/2038033.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

uncertainty
expert elicitation of lifetime
quantile function
Weibull distribution

Opis:

Managing the exploitation of technical equipment under conditions of uncertainty requires the use of probabilistic prediction models in the form of probability distributions of the lifetime of these objects. The parameters of these distributions are estimated with the use of statistical methods based on historical data about actual realizations of the lifetime of examined objects. However, when completely new solutions are introduced into service, such data are not available and the only possible method for the initial assessment of the expected lifetime of technical objects is expert methods. The aim of the study is to present a method for estimating the probability distribution of the lifetime for new technical facilities based on expert assessments of three parameters characterizing the expected lifetime of these objects. The method is based on a subjective Bayesian approach to the problem of randomness and integrated with models of classical probability theory. Due to its wide application in the field of maintenance of machinery and technical equipment, a Weibull model is proposed, and its possible practical applications are shown. A new method of expert elicitation of probabilities for any continuous random variable is developed. A general procedure for the application of this method is proposed and the individual steps of its implementation are discussed, as well as the mathematical models necessary for the estimation of the parameters of the probability distribution are presented. A practical example of the application of the developed method on specific numerical values is also presented.

Źródło:

Eksploatacja i Niezawodność; 2021, 23, 4; 757-769
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 18.

Tytuł:

Hybrid reliability modelling under general uncertainty

Autorzy:

Guo, R.
Cui, Y.
Thiart, C.
Guo, D.

Powiązania:

https://bibliotekanauki.pl/articles/2069636.pdf

Data publikacji:

2010

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

uncertain measure
hybrid lifetime
uncertain parameter
average chance reliability

Opis:

The real world phenomena are often facing the co-existence reality of different formality of uncertainty and thus the probabilistic reliability modeling practices are very doubtful. Under complicated uncertainty environments, hybrid variable modeling is important in reliability and risk analysis, which includes Bayesian distributional theory, random fuzzy distributional theory, as well as fuzzy random distributional theory as special distribution families. In this paper, we define a new hybrid lifetime which is specified by a random lifetime distribution with an uncertain distributed parameter, which is called as random uncertain hybrid lifetime. We furthermore define the average chance distribution as a quality index for quantifying the hybrid lifetime and accordingly the average chance reliability is derived.

Źródło:

Journal of Polish Safety and Reliability Association; 2010, 1, 1; 115--122
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 19.

Tytuł:

Technological solutions to extend the operating cycle of tools and industrial machinery

Autorzy:

Lukarski, Y.
Tashev, P.
Argirov, C.
Kondov, H.

Powiązania:

https://bibliotekanauki.pl/articles/391484.pdf

Data publikacji:

2017

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa

Tematy:

operational lifetime
new materials
overlay welding
thermo-chemical treatment

Opis:

One of the most significant problems that engineers and researchers face is the development of technological solutions to extend the exploitation cycle of tools and industrial machinery. The research shows there are a few possibilities to solve this problem: 1. Development of new materials of enhanced working characteristics compared to those currently used. An example of this is the introduction of new metals and alloys in the automotive industry, the mining industry, etc. 2. Preventive processing of assemblies and parts prior to their use consisting mainly in overlay welding with wear resistant layers or thermo-chemical surface treatment of the parts. 3. Recovering assemblies and parts after their resource has been depleted. This is mainly applied in the mining industry, road construction, etc. Worn-out tools are overlay welded and reused. It has been proven that the price of the recovered details is 2 to 20 times lower than that of the new ones. Moreover, it should be pointed out that the recovery saves energy and ore resources and thus a significant environmental impact is achieved.

Źródło:

Prace Instytutu Odlewnictwa; 2017, 57, 4; 253-258
1899-2439

Pojawia się w:

Prace Instytutu Odlewnictwa

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 20.

Tytuł:

Identification of heredity kernels and their influence on the life time of glass/polyester composites

Autorzy:

Olodo, E. T.
Adjovi, E. C.
Adanhounme, V.

Powiązania:

https://bibliotekanauki.pl/articles/955255.pdf

Data publikacji:

2014

Wydawca:

Uniwersytet Zielonogórski. Oficyna Wydawnicza

Tematy:

lepkosprężystość
parametry sprężyste
kompozyty
heredity kernels
viscoelastic parameters
lifetime

Opis:

One of the major problems encountered in prediction of hereditary viscoelastic behavior of polymeric composites is the determination of heredity kernels. This issue comes down to identification of the model characterizing the viscoelastic properties of these materials. The purpose of this work is to propose a model for prediction of viscoelastic nonlinear behavior of laminate composite with polyester matrix, through the study and analysis of heredity kernels and their influence on the life time of this material. Identification of this model required experimental determination at room temperature, of viscoelastic parameters of heredity kernels by macroscopic approach. These data provide predictive tools for establishment of the life time and long term stress limit under static complex loading for this type of material.

Źródło:

International Journal of Applied Mechanics and Engineering; 2014, 19, 4; 725-734
1734-4492
2353-9003

Pojawia się w:

International Journal of Applied Mechanics and Engineering

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 21.

Tytuł:

Gas turbine reliability model based on tangent hyperbolic reliability function

Autorzy:

Djeddi, A. Z.
Hafaifa, A.
Salam, A.

Powiązania:

https://bibliotekanauki.pl/articles/280120.pdf

Data publikacji:

2015

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

reliability estimation
reliability algorithms
lifetime distribution
Weibull distribution
availability

Opis:

The present work deals with the exploration of a new model proposed for the reliability analysis of industrial production systems. This proposed model is mainly based on the tangent hyperbolic function, where the survival function is determined and used in the lifetime distribution modeling taking into account of estimation the parameters of the proposed function. On the other side, tests validation is performed using the real data of a gas turbine installation. The obtained results allow the modeling of damage effects, hence the prediction of the performance of the examined gas turbine using the proposed model gives good results in terms of validity.

Źródło:

Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 723-730
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 22.

Tytuł:

Research on preventive maintenance strategies and systems for in-service ship equipment

Autorzy:

Song, Tingxin
Tan, Taiyang
Han, Guochen

Powiązania:

https://bibliotekanauki.pl/articles/32887248.pdf

Data publikacji:

2022

Wydawca:

Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa

Tematy:

preventive maintenance
FMEA
lifetime prediction
decision system
ship equipment

Opis:

With continuous improvements in the function and performance of ship equipment, mechanisms of failure have become more and more complicated. To avoid over-maintenance or under-maintenance in existing routine ship maintenance strategies, a ship-level method for repair decisions based on the preventive maintenance concept is proposed in this paper. First, the anticipated repair demand levels of key components are calculated using an improved failure mode and effects analysis (FMEA) method; second, a Weibull distribution model is established, and the parameters are estimated using the maximum likelihood estimation (MLE) to predict the characteristic life of the equipment; then, logical decision principles and rule-based reasoning (RBR) are used to determine the ship repair level and repair timing. Finally, the feasibility and application value of the proposed repair strategy were verified by case studies, and a ship-level system for repair decisions was established.

Źródło:

Polish Maritime Research; 2022, 1; 85-96
1233-2585

Pojawia się w:

Polish Maritime Research

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 23.

Tytuł:

Scheduling Based Wireless Sensor Networks Integrated with IoT Environment

Autorzy:

Mahendran, N.

Powiązania:

https://bibliotekanauki.pl/articles/1193556.pdf

Data publikacji:

2016

Wydawca:

Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN

Tematy:

Data Scheduling Schemes
Energy Efficient
IoT
Network lifetime
Sensor Network

Opis:

Wireless Sensor networks are widely adopt in military, target tracking, signal processing and monitoring applications like traffic and structural, the small and low cost unreliable sensor nodes in these applications uses batteries as the sole energy source. The energy efficiency becomes difficult task as the tiny and less weight battery act as source of each node. Scheduling the different category of data packets is a way to reduce the power consumption and increasing the lifetime of sensor nodes. The existing scheduling algorithms are not adapted to the environment changes. The basic FCFS (First Come First Serve) suffered by long delay while transmit the real time data packets. In DMP (Dynamic Multilevel Priority) real time data packets occupies highest priority, the remaining non real time data packets sent to lower priority level queues. Some real time task holds the resources for longer time, the other task have to wait, it makes the deadlock condition. The NJN (Nearest Job Next) will select the nearest requesting sensor node for service, real time packets have to wait long time. The proposed Adaptive weighted scheduling scheme changes the behavior of the network queue by adaptively changes the weights based on network traffic. Simulation results proof that, adaptive weighted scheduling algorithm works better than the FCFS and DMP data scheduling in terms of energy consumption and lifetime. Our future scheme to integrate Internet of Things (IoT) with the WSN to increase the performance of the wireless networks.

Źródło:

World Scientific News; 2016, 41; 116-127
2392-2192

Pojawia się w:

World Scientific News

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 24.

Tytuł:

EEULA: an energy-aware event-driven unicast algorithm for wireless sensor network by learning automata

Autorzy:

Kashani, A. A. S.
Noori, A. M. M.

Powiązania:

https://bibliotekanauki.pl/articles/102180.pdf

Data publikacji:

2016

Wydawca:

Stowarzyszenie Inżynierów i Techników Mechaników Polskich

Tematy:

network lifetime
wireless sensor network
learning automata
energy efficiency algorithm

Opis:

Energy consumption is one of the major challenges in wireless sensor networks, thus necessitating an approach for its minimization and for load balancing data. The network lifetime ends with the death of one of its nodes, which, in turn, causes energy depletion in and partition of the network. Furthermore, the total energy consumption of nodes depends on their location; that is, because of the loaded data, energy discharge in the nodes close to the base station occurs faster than other nodes, the model presented here, through using learning automata, selects the path appropriate for data transferring; the selected path is rewarded or penalized taking the reaction of surrounding paths into account. We have used learning automata for energy management in finding the path; the routing protocol was simulated by NS2 simulator; the lifetime, energy consumption and balance in an event-driven network in our proposed method were compared with other algorithms.

Źródło:

Advances in Science and Technology. Research Journal; 2016, 10, 30; 9-18
2299-8624

Pojawia się w:

Advances in Science and Technology. Research Journal

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 25.

Tytuł:

Estimation of high temperature fatigue lifetime of SUS304 steel with an energy parameter in the critical plane
Ocena wysokotemperaturowej trwałości zmęczeniowej stali SUS304 za pomocą parametru energetycznego w płaszczyźnie krytycznej

Autorzy:

Łagoda, T.
Macha, E.
Sakane, M.

Powiązania:

https://bibliotekanauki.pl/articles/281113.pdf

Data publikacji:

2003

Wydawca:

Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej

Tematy:

low-cycle fatigue
multiaxial fatigue
energy approach
lifetime
high temperature

Opis:

The paper studies the application of the energy parameter, a sum of elastic and plastic strain energy densities in the critical plane, for the correlation of two series of proportional biaxial low-cycle lives using SUS304 stainless steel at elevated temperature. The first data used thin-walled cylinder specimens subjected to 7 proportional strain paths of combined tension-torsion and the other used cruciform specimens subjected to 5 proportional strain paths of biaxial tension-compression. These tests were done at the temperature of 923 K. The normal total strain energy density in the plane with the maximum damage was a suitable parameter for describing the test results.
Praca dotyczy zastosowania parametru energetycznego, sumy gęstości energii sprężystej i plastycznej odkształcenia w płaszczyźnie krytycznej do korelacji dwóch serii proporcjonalnych, dwuosiowych, niskocyklowych trwałości zmęczeniowych stali nierdzewnej SUS303 w podwyższonej temperaturze.Badano cienkościenne próbki cylindryczne poddane siedmiu proporcjonalnym torom odkształcenia w warunkach kombinacji rozciągania-skręcania oraz próbki krzyżowe poddane pięciu proporcjonalnym torom odkształcenia w warunkach dwuosiowego rozciągania-ściskania. Badania prowadzono w temperaturze 923 K. Gęstość energii całkowitego odkształcenia normalnego w płaszczyźnie maksymalnego uszkodzenia była odpowiednim parametrem do opisania wyników badań.

Źródło:

Journal of Theoretical and Applied Mechanics; 2003, 41, 1; 55-73
1429-2955

Pojawia się w:

Journal of Theoretical and Applied Mechanics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 26.

Tytuł:

Steady and transient thermal state of turbine disc estimation for life time monitoring
Stałe i przejściowe oszacowanie stanu termicznego tarczy turbiny w celu monitorowania jej żywotności

Autorzy:

Martseniuk, Yevhen

Powiązania:

https://bibliotekanauki.pl/articles/36416847.pdf

Data publikacji:

2020

Wydawca:

Sieć Badawcza Łukasiewicz - Instytut Lotnictwa

Tematy:

lifetime
monitoring
thermal-stress state
model
żywotność
stan naprężenia termicznego

Opis:

In connection with increasing intensification of the working process in a gas turbine engine and increasing requirements for economy, the problem of defining and monitoring the main parts lifetime is becoming more vital. Modern algorithms of the monitoring systems are based on taking into account the levels of part temperature and total equivalent stress throughout the flight cycle. Thermal and stressstrain states of the critical zones of the main parts are determined on the basis of information received from the sensors installed in the engine gas path. Turbine disks are located in the internal cavities of the engine and are cooled by air from the compressor. However, in some designs, the disk cavity can be separated from the place of cooling air bleed by several stages of non-contact labyrinth seals, which will lead to some delay in changing the parameters of the cooling air flow when changing the engine operating mode. It has been observed that if this situation is not taken into account, it can lead to significant errors (more than 40%) in determining the lifetime for the peripheral zone of the disk. At the same time, this error is minimal for the hub and the middle zone of the disk, and the existing monitoring algorithms can be used.
W związku z coraz większą intensyfikacją procesu pracy w silniku turbiny gazowej i rosnącymi wymaganiami ekonomicznymi, coraz bardziej zaostrza się problem definiowania i monitorowania żywotności głównych części. Nowoczesne algorytmy systemów monitorowania opierają się na uwzględnianiu poziomów temperatury części i całkowitego równoważnego obciążenia w całym cyklu lotu. Stany termiczne i naprężeniowo-odkształceniowe stref krytycznych części głównych określane są na podstawie informacji otrzymywanych z czujników zainstalowanych w torze gazowym silnika. Tarcze turbinowe umieszczone są w wewnętrznych wnękach silnika i są chłodzone powietrzem ze sprężarki. Jednak w niektórych konstrukcjach wnęka tarczowa może być oddzielona od miejsca upustu powietrza chłodzącego kilkoma stopniami bezdotykowych uszczelnień labiryntowych, co spowoduje pewne opóźnienie zmiany parametrów przepływu powietrza chłodzącego przy zmianie trybu pracy silnika. Wykazano, że jeśli sytuacja ta nie będzie brana pod uwagę, może to prowadzić do znacznych błędów (ponad 40%) w określeniu okresu eksploatacji dla strefy peryferyjnej tarczy. Jednocześnie błąd ten jest minimalny dla koncentratora i strefy środkowej dysku, a istniejące algorytmy monitorujące mogą być stosowane.

Źródło:

Transactions on Aerospace Research; 2020, 3 (260); 21-29
0509-6669
2545-2835

Pojawia się w:

Transactions on Aerospace Research

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 27.

Tytuł:

Optimal credit period and ordering quantity for credit dependent trended demand and deteriorating items with maximum lifetime

Autorzy:

Shah, N. H.
Shah, D. B.
Patel, D. G.

Powiązania:

https://bibliotekanauki.pl/articles/970075.pdf

Data publikacji:

2015

Wydawca:

Polska Akademia Nauk. Instytut Badań Systemowych PAN

Tematy:

inventory
trended demand
trade credit
default risk
deterioration
maximum lifetime

Opis:

In this paper, an inventory system is analyzed regarding a trended demand. The seller offers its buyer a credit period for settling the account, which attracts more buyers and enhances market demand. However, the offer of credit period leads to default risk for the supplier. The units in inventory are deteriorating continuously and also have definite maximum lifetime. The aim is to maximize the profit of the retailer. Numerical examples are given to validate the developed mathematical model. Sensitivity analysis is performed to obtain the critical inventory parameters and deduce the managerial strategies.

Źródło:

Control and Cybernetics; 2015, 44, 2; 311-320
0324-8569

Pojawia się w:

Control and Cybernetics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 28.

Tytuł:

Lifetime distributions with wave-like bathtub hazard

Autorzy:

Guo, R.
Thiart, C.
Cui, Y.
Guo, D.

Powiązania:

https://bibliotekanauki.pl/articles/2069543.pdf

Data publikacji:

2011

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

lifetime distribution
hazard
bathtub hazard
likelihood function
maximum likelihood estimation

Opis:

In this paper, we argue the necessity of dealing with lifetime distributions with wave-like bathtub hazard function. Four classes of wave-like bathtub hazards are investigated. For preparing maximum likelihood estimation of the hazard parameters, the first-order and second-order partial derivatives are derived.

Źródło:

Journal of Polish Safety and Reliability Association; 2011, 2, 1; 115--122
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 29.

Tytuł:

The Weibull lifetime model with randomised failure-free time

Autorzy:

Sulewski, Piotr
Szymkowiak, Magdalena

Powiązania:

https://bibliotekanauki.pl/articles/2156948.pdf

Data publikacji:

2022-12-15

Wydawca:

Główny Urząd Statystyczny

Tematy:

Weibull lifetime model
randomised failure-free time
compound Weibull distributions

Opis:

The paper shows that treating failure-free time in the three-parameter Weibull distribution not a constant, but as a random variable makes the resulting distribution much more flexible at the expense of only one additional parameter.

Źródło:

Statistics in Transition new series; 2022, 23, 4; 59-76
1234-7655

Pojawia się w:

Statistics in Transition new series

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 30.

Tytuł:

Optimization of critical infrastructure operation and safety with considering climate-weather change influence : maximizing safety lifetime

Autorzy:

Kołowrocki, K.
Kuligowska, E.
Soszyńska-Budny, J.

Powiązania:

https://bibliotekanauki.pl/articles/2068785.pdf

Data publikacji:

2018

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

critical infrastructure
safety
operation process
climate-weather change
optimization
safety lifetime

Opis:

The method based on the results of the joint model linking a semi-Markov modelling of the critical infrastructure operation process with a multistate approach to critical infrastructure safety and linear programming are proposed to the critical infrastructure operation and safety optimization. This method determining the optimal values of limit transient probabilities at the critical infrastructure operation states that maximize the critical infrastructure safety lifetime in the safety state subsets is proposed.

Źródło:

Journal of Polish Safety and Reliability Association; 2018, 9, 1; 1--10
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 31.

Tytuł:

Reliability concept under general uncertainty

Autorzy:

Guo, R.
Cui, Y.
Thiart, C.
Guo, D.

Powiązania:

https://bibliotekanauki.pl/articles/2069525.pdf

Data publikacji:

2010

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

probabilistic reliability
uncertain reliability
uncertain measure
uncertainty lifetime
uncertain hazard function

Opis:

The Toyota crisis is tearing off the brand image of quality and reliability and therefore it is logical to question whether the dominating position of probability theory, on which Japanese quality and reliability engineering practices are established, should be examined. In general, reliability analysis is an exercise under uncertain environment. Foundationally speaking, uncertain modeling is a matter of choosing what kind of uncertain measure as its standing point. In this paper, we introduce the uncertainty reliability concept on the platform of the axiomatic uncertain measure theory and compare it to probabilistic reliability concept based on Kolmogorov’s probability measure theory, on which the traditional quality and reliability engineering is established. It is expecting that a foundational work can be established for a more rigorous reliability engineering and risk analysis under general uncertainty environments.

Źródło:

Journal of Polish Safety and Reliability Association; 2010, 1, 1; 105--114
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 32.

Tytuł:

On a general standby system and its optimization

Autorzy:

Cha, J. H.
Yun, W. Y.

Powiązania:

https://bibliotekanauki.pl/articles/2069693.pdf

Data publikacji:

2009

Wydawca:

Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności

Tematy:

warm standby
accelerated life testing
virtual age
switching time
mean lifetime

Opis:

Redundancy or standby is a technique that has been widely applied to improving system reliability and availability in the stage of system design. In this paper, we consider a standby system with two units in which the first unit (unit 1) starts its operation under active state and the other unit (unit 2) is under cold standby state at the starting point. After a specified time s (switching time), the state of unit 2 is changed to warm standby state and, as soon as the operating unit 1 fails, the state of unit 2 is changed to active state. If unit 1 fails before times, the system fails. Units can fail at both active and warm standby states. A general method for modeling the standby system is adopted and, based on it, system performance measures (system reliability and mean life) are derived. We consider the problem of determining optimal switching time which maximizes the expected system life. Some numerical examples are studied.

Źródło:

Journal of Polish Safety and Reliability Association; 2009, 1; 95--100
2084-5316

Pojawia się w:

Journal of Polish Safety and Reliability Association

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 33.

Tytuł:

Positron annihilation lifetime spectroscopy study of thermal processing and rehydration of dry leek (Allium porrum L.)

Autorzy:

Zaleski, R.
Wawryszczuk, J.
Sobczak, K.

Powiązania:

https://bibliotekanauki.pl/articles/146309.pdf

Data publikacji:

2010

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

positron annihilation
lifetime spectroscopy
food processing
rehydration
leek (Allium porrum L.)

Opis:

New application of positron annihilation lifetime spectroscopy (PALS) to development of food processing techniques is tested. Dehydrated leeks were an object of the study. Three experiments were performed consisting of evacuating air and volatile compounds from the sample, applying thermal treatment and rehydrating the sample. Distinct changes in positron lifetime spectra allowed the monitoring of alterations in the sample structure. The most likely origin of the particular components present in the spectra was able to be proposed from these data. Changes of the components were ascribed to the various processes occurring in the samples.

Źródło:

Nukleonika; 2010, 55, 1; 73-78
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 34.

Tytuł:

On useful schema in survival analysis after heart attack

Autorzy:

Stępniak, Czesław

Powiązania:

https://bibliotekanauki.pl/articles/729744.pdf

Data publikacji:

2014

Wydawca:

Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii

Tematy:

lifetime after heart attack
distribution
Fibonacci number
Lucas number
Pascal triangle

Opis:

Recent model of lifetime after a heart attack involves some integer coefficients. Our goal is to get these coefficients in simple way and transparent form. To this aim we construct a schema according to a rule which combines the ideas used in the Pascal triangle and the generalized Fibonacci and Lucas numbers

Źródło:

Discussiones Mathematicae Probability and Statistics; 2014, 34, 1-2; 63-69
1509-9423

Pojawia się w:

Discussiones Mathematicae Probability and Statistics

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 35.

Tytuł:

Fatigue lifetime correction of structural joints Indexed by: of opencast mining machinery

Autorzy:

Grabowski, Paweł
Jankowiak, Artur
Marowski, Witold

Powiązania:

https://bibliotekanauki.pl/articles/2038154.pdf

Data publikacji:

2021

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

fatigue life
lifetime assessment
supporting structure
welded joints
opencast mining machinery

Opis:

Opencast mining machinery represents a group of large-scale individually manufactured technical objects operated with long-life requests. Since their manufacturers are obliged to provide product that will reach declared time of life, fatigue strength and durability conditions have to be taken into account for superstructures to meet the requirements. The paper highlights main problems occurring while assessing fatigue lifetime during design. Firstly, the short survey of current state of the art regarding the approach to this problem is presented. Secondly, the most important reasons of unsatisfactory accuracy of the assessments are discussed. As a main objective of the study, the authors introduce the unique method of continuous fatigue lifetime correction for the welded superstructures during the machine lifecycle, as a remedy for this group of machinery. Furthermore, results and experience from adapting the approach in real object are presented, including fatigue lifetime correction due to the real intensity of loading acquired from a bucket-wheel excavator during its longlasting operation. It is expected that proposed procedure can help to improve credibility of fatigue lifetime assessment of heavy earthmoving machinery.

Źródło:

Eksploatacja i Niezawodność; 2021, 23, 3; 530-539
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 36.

Tytuł:

Lifetime performance evaluation model based on quick response thinking

Autorzy:

Chiou, Kuo-Ching
Chen, Kuen-Suan

Powiązania:

https://bibliotekanauki.pl/articles/2057979.pdf

Data publikacji:

2022

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

lifetime performance index
Type-II right censoring
UMVU estimators
UMP test

Opis:

In practice, lifetime performance index CL has been a method commonly applied to the evaluation of quality performance. L is the upper or lower limit of the specification. The product lifetime distribution is mostly abnormal distribution. This study explored that the lifetime of commodities comes from exponential distribution. Complete data collection is the primary goal of analysis. However, the censoring type is one of the most commonly used methods due to considerations of manpower and material cost or the timeliness of product launch. This study adopted Type-II right censoring to find out the uniformly minimum variance unbiased (UMVU) estimator of the lifetime performance index CL and its probability density function. Afterward this study obtained the 100×(1-α)% confidence interval of the lifetime performance index CL as well as created the uniformly most powerful (UMP) test and the power of the test for the product lifetime performance index. Last, this study came up with a numerical example to demonstrate the suggested method as well as the application of the model.

Źródło:

Eksploatacja i Niezawodność; 2022, 24, 1; 1--6
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 37.

Tytuł:

Improvement of enzyme stability via non-covalent complex formation with dextran against temperature and storage lifetime

Autorzy:

Altikatoglu, M.
Kuzu, H.

Powiązania:

https://bibliotekanauki.pl/articles/778394.pdf

Data publikacji:

2010

Wydawca:

Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie

Tematy:

stabilizacja termiczna
enzymy
dekstran
thermal stabilization
complex
enzyme
dextran
storage lifetime

Opis:

The optimal methodology to prepare the novel modified enzyme, polymer-enzyme complex, was developed to give a high catalytic activity in aqueous solution. The non-covalent complexes of two different enzymes (horseradish peroxidase and glucose oxidase) were prepared with various molar ratios (nD/nE 0,05; 0,1; 1; 5; 10; 15; 20) by using 75kDa dextran. The thermal stabilities of the obtained complexes were evaluated with the activities determined at different temperatures (25, 30, 35, 40, 50, 60, 70, 80°C) applying 60 minutes incubation time for pH 7. The complexes with the molar ratio nD/nHRP: 10 and nD/nGOD: 5 showed the highest thermal stability. Its activity was very high (ca. 1,5-fold higher activity than pure enzyme for HRP-dextran complexes) and almost the same between applying one hour incubation time and without incubation, and could also be measured at high temperatures (70, 80 °C). We finally succeeded in preparing dextran-enzyme complexes which showed higher activity than pure enzyme in aqueos solution at all temperatures for pH 7. In addition, the mentioned complexes at pH 7 had very long storage lifetime compared to purified enzyme at +4 °C; which is considered as a good feature for the usage in practice.

Źródło:

Polish Journal of Chemical Technology; 2010, 12, 1; 12-16
1509-8117
1899-4741

Pojawia się w:

Polish Journal of Chemical Technology

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 38.

Tytuł:

Influence of antifreeze proteins on local waters structure dynamics in presence of osmolytes

Autorzy:

Krishnamoorthy, A. N.

Powiązania:

https://bibliotekanauki.pl/articles/1933947.pdf

Data publikacji:

2013

Wydawca:

Politechnika Gdańska

Tematy:

hydration dynamics
hydrogen bond lifetime
osmolytes
Kirkwood-Buff integrals
prefential binding parameter

Opis:

Antifreeze proteins are synthesized by various organisms to enable their cells to survive subzero environment in the arctic and polar regions. These proteins produce a difference between the melting and freezing points termed as thermal hysteresis. The main objective of this study is to examine the dynamics of water molecules and hydrogen bonds at the protein-water interface of antifreeze protein using atomistic molecular dynamics simulations using GROMACS. For this work a prototype of AFP (antifreeze protein) from antarctic notothenioids (ala-ala-thr repeats) and a mutant which is not antifreeze active were generated using PRODRG server. The hydration dynamics results revealed that the retarded water dynamics in the AFP compared to its mutant was responsible for the antifreeze activity. Furthermore a considerable increase in antifreeze activity were observed for the AFP in presence of osmolytes. The mechanism of action were tested using preferential binding parameter derived from Kirkwood-Buff integerals.

Źródło:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2013, 17, 1-2; 5-42
1428-6394

Pojawia się w:

TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 39.

Tytuł:

PALS investigation of resorcinol under high pressure

Autorzy:

Tydda, M.
Jasińska, B.
Pieniążek, A.

Powiązania:

https://bibliotekanauki.pl/articles/147999.pdf

Data publikacji:

2013

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

free volume
ortho-positronium (o-Ps)
pressure
positron annihilation lifetime spectroscopy (PALS)

Opis:

Two kinds of measurements were conducted with resorcinol at high pressure : the first one with the use of a mechanical press and the second one with the use of a gaseous compressor. In the second case, due to some gas penetrating the material structure, the lifetime spectra obtained were difficult to analyze. The free volumes in resorcinol were influenced both by high pressure and the gas coming into the crystallographic structure.

Źródło:

Nukleonika; 2013, 58, 1; 195-198
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 40.

Tytuł:

Principles of positron porosimetry

Autorzy:

Zaleski, R.

Powiązania:

https://bibliotekanauki.pl/articles/146520.pdf

Data publikacji:

2015

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

porous materials
positron annihilation lifetime spectroscopy (PALS)
positronium
extended Tao-Eldrup model

Opis:

The paper deals with positron porosimetry (PP), which is based on positron annihilation lifetime spectroscopy (PALS). The numerical analysis of positron lifetime spectra for PP is more demanding than in most of other applications of PALS. The resulting intensity distributions of ortho-positronium (o-Ps) lifetimes are interpreted in terms of the extended Tao-Eldrup (ETE) model, which provides the dependence between the o-Ps lifetime and pore size. Additionally, the relation between the intensity of an o-Ps component and the pore volume allows obtaining pore size distribution (PSD). The value of the empirical parameter Δ, which is dependent on material, can be estimated from the temperature dependence of an o-Ps lifetime. The most unique feature of PP among other techniques that allow determination of PSDs is its ability to perform measurements in almost any conditions. This makes this method suitable for various in situ studies. In this review article, both the capabilities and the limitations of PP are discussed. The methods to overcome some of the limitations are presented.

Źródło:

Nukleonika; 2015, 60, No. 4, part 1; 795-800
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 41.

Tytuł:

A new approach to diagnostic symptom assessment based on information content measures
Nowa metoda oceny symptomów diagnostycznych oparta na miarach zawartości informacji

Autorzy:

Gałka, T.

Powiązania:

https://bibliotekanauki.pl/articles/327786.pdf

Data publikacji:

2016

Wydawca:

Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN

Tematy:

lifetime consumption
diagnostic symptom
information content
wyczerpywanie żywotności
symptom diagnostyczny
zawartość informacji

Opis:

A complex diagnostic object typically generates a large number of diagnostic symptoms. For proper lifetime consumption monitoring it is necessary to select those which best represent technical condition deterioration. Such selection may be based on the Singular Value Decomposition method. The paper presents a novel alternative approach, which employs an information content measure. As the end of object life is approached, symptoms are to an increasing extent dominated by deterministic lifetime consumption processes and therefore become more predictable. Thus symptoms with the highest information content decrease rate should be considered most useful. For a proper assessment, however, symptom sensitivity to condition parameters should also be addressed. A new measure referred to as representativeness factor is proposed. Suitability of such approach is demonstrated for the fluid-flow system of a large steam turbine.
Złożone obiekty diagnozowania zwykle są źródłem wielu symptomów diagnostycznych. Dla właściwego monitorowania wyczerpywania żywotności należy wybrać te z nich, które najlepiej odwzorowują degradację stanu technicznego. Wybór ten można oprzeć na metodzie rozkładu względem wartości szczególnej. W pracy przedstawiono nowatorskie alternatywne podejście, w którym wykorzystuje się miarę zawartości informacji. Wraz ze zbliżaniem się do końca życia obiektu symptomy są w coraz większym stopniu określone przez deterministyczne procesy ubytku żywotności, a zatem stają się coraz bardziej przewidywalne. Za najbardziej użyteczne należy zatem uznać symptomy z najszybszym spadkiem zawartości informacji. We właściwej ocenie należy jednak uwzględnić także wrażliwość symptomu na parametry stanu. Zaproponowano nową miarę określoną jako współczynnik reprezentatywności. Przydatność takiego podejścia została zademonstrowana na przykładzie układu przepływowego turbiny parowej.

Źródło:

Diagnostyka; 2016, 17, 3; 103-108
1641-6414
2449-5220

Pojawia się w:

Diagnostyka

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 42.

Tytuł:

Ortho-positronium migration in mesopores of MCM-41, MSF and SBA-3

Autorzy:

Zaleski, R.
Błażewicz, A.
Kierys, A.

Powiązania:

https://bibliotekanauki.pl/articles/147955.pdf

Data publikacji:

2013

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

nitrogen adsorption/desorption
porous materials
positron annihilation lifetime spectroscopy (PALS)
positronium migration

Opis:

Three materials: MCM-41, MSF and SBA-3 with a very similar pore diameter but different lengths of cylindrical pores were investigated using the nitrogen sorption method and positron annihilation lifetime spectroscopy. The size of primary pores and interparticle spaces obtained by both methods is similar. However, volume ratios between the discussed kinds of pores found by the above-mentioned methods differ significantly. Such discrepancy is the result of both ortho-positronium migration and the inaccessibility of the pores for nitrogen. Comparing the results of nitrogen sorption and positron annihilation lifetime spectroscopy allows us to estimate that connectivity between the primary pores and the interparticle spaces is the highest in MCM-41 and lowest in SBA-3.

Źródło:

Nukleonika; 2013, 58, 1; 235-240
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 43.

Tytuł:

Radiation Degradation of Bipolar Transistor Current Gain

Autorzy:

Miskiewicz, S.
Komarov, A.
Komarov, F.
Zayats, G.
Soroka, S.

Powiązania:

https://bibliotekanauki.pl/articles/1033766.pdf

Data publikacji:

2017-08

Wydawca:

Polska Akademia Nauk. Instytut Fizyki PAN

Tematy:

radiation
numerical simulation
bipolar transistors
lifetime
minority charge carriers
recombination
current gain

Opis:

Spatial distribution of nonequilibrium minority charge carriers in bipolar transistors before and during the radiation exposure is described. Radiation-induced changes in the input and output characteristics and the current gain under the ⁶⁰Co 1.2 MeV γ -rays were calculated. It was shown that the collector current and current gain steadily fall due to irradiation in the considered range in the dose range 0-7×10⁵ rad. The simulation results correlate well with the experimental data obtained at the Research and Production Corporation "Integral".

Źródło:

Acta Physica Polonica A; 2017, 132, 2; 288-290
0587-4246
1898-794X

Pojawia się w:

Acta Physica Polonica A

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 44.

Tytuł:

TiO2 modified by ammonia as a long lifetime photocatalyst for dyes decomposition

Autorzy:

Choina, J.
Dolat, D.
Kusiak, E.
Janus, M.
Morawski, A.W.

Powiązania:

https://bibliotekanauki.pl/articles/778832.pdf

Data publikacji:

2009

Wydawca:

Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie

Tematy:

fotokataliza
TiO2 modyfikowany azotem
żywotność
photocatalysis
nitrogen-modified TiO2
lifetime

Opis:

Ammonia-modified TiO2 (TiO2/N), prepared in a pressure reactor was used as the well- active and longlife photocatalyst for the azo dye (Reactive Red 198) decomposition. The effect of aeration and the different value of the pH of the reaction medium on the photocatalytic degradation of Reactive Red 198 in water has been investigated. It has been reported that the degradation is greatly influenced by the reaction pH and the faster decomposition of azo dye took place at pH 3.5. When the solution was acidic, a larger amount of azo dye on the positively charged surface of TiO2 photocatalysts was adsorbed. From the obtained results it can be seen that the effectiveness of the decolourisation of the solution was faster by using the nitrogen-modified TiO2.

Źródło:

Polish Journal of Chemical Technology; 2009, 11, 4; 1-6
1509-8117
1899-4741

Pojawia się w:

Polish Journal of Chemical Technology

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 45.

Tytuł:

Analysis of mileage to engine oil removing in the natural exploitation of passenger cars
Analiza przebiegów do wymiany oleju silnikowego w eksploatacji naturalnej samochodów

Autorzy:

Sitnik, L. J.

Powiązania:

https://bibliotekanauki.pl/articles/245595.pdf

Data publikacji:

2009

Wydawca:

Instytut Techniczny Wojsk Lotniczych

Tematy:

eksploatacja
silnik pojazdu
olej silnikowy
czasokres
exploitation
car engine
engine oil
lifetime
analysis

Opis:

Leading to reformation of proecologic abilities of transport's vehicles and especially cars vehicles are connected with properly economy of the working liquids. It intakes should be optimal. This postulate is working in an activity of cars' tycoons and producers of working liquids. In this case a good example is lifetime of engines' oils. By one hand it leads to lengthen of engine's oil lifetime by improvement of its abilities, by second hand producers are limiting time of oil's change but admittedly that mileage is constantly rising. Everything it leads to constantly drop of the oil's unit consumption. There are exist extra possibilities of improving an oil consumption if oil's unit consumption treats like proecologic parameter. The base of that are changes in oil lifetime based on exploitations' terms for particular copy of vehicle. By one hand it secures of properly use car vehicle by second hand it resists the human factor in exploitation process, thanks that it excludes situations where oil will be changed to early - as a consequence of extra consumption or to late - as a probability of engines' damages. From the analysis of solid constant mileage to change engine's oil comes how big problem is it. Properly researches and conclusions presented in this publication.
Dążenie do poprawy proekologicznych właściwości środków transportu, w tym samochodów osobowych, związane jest, między innymi, z prawidłową gospodarką płynami roboczymi. Ich zużycie powinno być optymalizowane. Postulat ten jest urzeczywistniany w działalności zarówno wytwórców pojazdów jak też producentów płynów eksploatacyjnych. Dobrym przykładem jest tu kwestia zużycia olejów silnikowych. Z jednej strony dąży się do tego by oleje mogły pracować jak najdłużej - ciągle doskonaląc ich właściwości, z drugiej producenci ograniczają przebiegi do ich wymiany, ale przyznać trzeba, że przebiegi te ulegają ciągłemu wzrostowi. Wszystko to prowadzi do nieustannego „jednostkowego" obniżania zużycia oleju silnikowego. Jeśli traktować jednostkowe zużycie oleju silnikowego jako parametr o znaczeniu proekologicznym to trzeba stwierdzić, że istnieją dalsze możliwości jego poprawy. Podstawową jest wprowadzenie elastycznych przebiegów do wymian oleju, wynikających z warunków eksploatacji konkretnego egzemplarza pojazdu. Z jednej strony zabezpiecza to właściwe użytkowanie pojazdu, z drugiej natomiast, powoduje znaczne ograniczenie ingerencji „ czynnika ludzkiego " w proces eksploatacji, a zatem pozwala wykluczyć sytuacje gdzie olej silnikowy wymieniany jest przedwcześnie - co skutkuje nieuzasadnionym jego zużyciem, lub zbyt późno - co wzmaga prawdopodobieństwo uszkodzeń silnika. O tym jak ważny jest to problem można przekonać się analizują dane dotyczące „sztywnych" przebiegów do wymiany oleju silnikowego. Odpowiednie badania i wynikające stąd wnioski, przedstawiono w niniejszej publikacji.

Źródło:

Journal of KONES; 2009, 16, 3; 367-373
1231-4005
2354-0133

Pojawia się w:

Journal of KONES

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 46.

Tytuł:

Photoluminescence and positron annihilation lifetime studies on pellets of ZnO nanocrystals

Autorzy:

Karbowski, A.
Fedus, K.
Patyk, J.
Bujak, Ł.
Służewski, K.
Karwasz, G.

Powiązania:

https://bibliotekanauki.pl/articles/148001.pdf

Data publikacji:

2013

Wydawca:

Instytut Chemii i Techniki Jądrowej

Tematy:

photoluminescence (PL)
positron annihilation lifetime spectroscopy (PALS)
X-ray diffraction (XRD)
ZnO nanocrystals

Opis:

We explore the interrelationships between the X-ray diffraction patterns, the photoluminescence spectra and the positron lifetimes obtained from circular pellets composed of commercial ZnO nanoparticles. The experimental results are studied as a function of thermal treatment at different temperatures. X-ray diffractograms reveal the temperature- independent wurtzite phase structure of nanocrystals and show huge enlargement of ZnO grains after annealing at temperatures higher than 700 centigrade. Photoluminescence measurements exhibit two emission bands : a near band edge emission in UV (small tilde 378 nm) and a defect-related broad visible peak with a maximum in the green region ( small tilde 502 nm). The significant enhancement of the green emission at the expense of UV luminescence is observed after sample sintering at 800 and 1000 centigrade. The positron annihilation lifetime spectroscopy (PALS) is applied in order to study the thermally induced evolution of defects. The lifetime components show a step-like dependence on the thermal treatment, but do not follow exactly the variation in crystallographic phases and only vaguely follow differences in photoluminescence. The positron data indicate therefore some additional structural and/or defect changes. The possible origin of green luminescence from ZnO pellets is discussed.

Źródło:

Nukleonika; 2013, 58, 1; 189-194
0029-5922
1508-5791

Pojawia się w:

Nukleonika

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 47.

Tytuł:

Generalized extended Marshall-Olkin family of lifetime distributions

Autorzy:

Goldoust, Mehdi
Mohammadpour, Adel

Powiązania:

https://bibliotekanauki.pl/articles/2034093.pdf

Data publikacji:

2022-03-15

Wydawca:

Główny Urząd Statystyczny

Tematy:

compound distribution
hazard rate function
lifetime distribution
maximum likelihood estimation
power series distribution

Opis:

We introduce a new generalized family of nonnegative continuous distributions by adding two extra parameters to a lifetime distribution, called the baseline distribution, by twice compounding a power series distribution. The new family, called the lifetime power series-power series family, has a serial arrangement of parallel structures, which extends the Marshall and Olkin structure. Four special models are discussed. A mathematical treatment of the new distributions is provided, including ordinary and incomplete moments, quantile, moment generating and mean residual functions. The maximum likelihood estimation technique is used to estimate the model parameters and a simulation study is conducted to investigate the performance of the maximum likelihood estimates. Its applicability is also illustrated by means of two real data sets.

Źródło:

Statistics in Transition new series; 2022, 23, 1; 55-74
1234-7655

Pojawia się w:

Statistics in Transition new series

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 48.

Tytuł:

SRH suppression mechanism in a non-equilibrium MWIR HgCdTe photodiode

Autorzy:

Kopytko, Małgorzata

Powiązania:

https://bibliotekanauki.pl/articles/2204220.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich

Tematy:

HgCdTe photodiode
non-equilibrium conditions
fully-depleted photodiode
minority carrier lifetime
generation rates

Opis:

The operation of narrow-gap semiconductor devices under non-equilibrium mode is used at temperatures where the materials are normally intrinsic. The phenomenon of minority carrier exclusion and extraction was particularly discussed in the case of the suppression of Auger thermal generation in heterojunction photodiodes, especially important in the long-wave infrared range. This paper shows that the reduction of the dark current in the HgCdTe photodiode operating in the mid-wave infrared range is primarily the result of suppression of the Shockley-Read-Hall generation in the non-equilibrium absorber. Under a reverse bias, the majority carrier concentration is held equal to the majority carrier doping level. This effect also leads to a decreased majority carrier population at the trap level and an effective increase in the carrier lifetime. The analysed device was with the following design: p+-Bp cap-barrier unit, p-type absorber doped at the level of 8 ·10¹⁵ cm¯³, and wide-bandgap N+ bottom contact layer. At room temperature, the lowest dark current density of 3.12 ·10¯¹ A/cm² was consistent with the theoretically predicted Shockley-Read-Hall suppression mechanism, about two times smaller than for the equilibrium case.

Źródło:

Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144548
1230-3402

Pojawia się w:

Opto-Electronics Review

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 49.

Tytuł:

Time and Transformation in Autobiography. Candia McWilliam’s What to Look for in Winter: A Memoir in Blindness
Czas i transformacja w autobiografii What to Look for in Winter: A Mamoir in Blindness Candii McWilliam

Autorzy:

Mildorf, Jarmila

Powiązania:

https://bibliotekanauki.pl/articles/37551248.pdf

Data publikacji:

2024

Wydawca:

Akademia Ignatianum w Krakowie

Tematy:

autobiografia
życiopisanie
transformacja
tożsamość autobiograficzna
pamięć
autobiography
lifetime
transformation
narrative and self
memory

Opis:

In this article, I discuss transformations of self over time in Candia McWilliam’s memoir What to Look for in Winter. In this book, the author writes about many life-changing events: her mother’s suicide, her two failed marriages, her alcoholism and her blindness, to name only a few. However, the book itself constitutes an attempt at transforming these experiences in the act of writing, to offer restitution to a life gone awry. Time plays a major role in this endeavour, both in the story told and in the way it is told. Anchored primarily in two ‘present’ moments in the first and second halves of the book, the narrative moves back and forth in time, taking the reader on a painful journey through the author’s past. Time furthermore serves as an overarching metaphor for transformations especially due to illness, as can already be seen in the book title’s reference to the seasons. What emerges is a highly complex literary autobiography in which life storytelling meshes with metanarrative reflection.
Artykuł dotyczy transformacji dokonanej w czasie w obrębie osobowości autobiograficznej, która została przedstawiona we wspomnieniach Candii McWilliam, zatytułowanych What to Look for in Winter. Autorka opisuje wiele trudnych doświadczeń, między innymi samobójstwo matki, dwa nieudane małżeństwa, alkoholizm oraz utratę wzroku. Mimo doświadczonych niepowodzeń autobiografia McWilliam stanowi próbę odzyskania równowagi w procesie twórczym, który ma pomóc nadać życiu utracony sens. Czas odgrywa główną rolę zarówno w samej historii jej życia, jak i w literackim jej przedstawieniu. Zamiast chronologicznego ukazania wydarzeń z przeszłości autorka konstruuje opowieść w odniesieniu do dwóch wymiarów teraźniejszości, którym odpowiadają dwie odrębne części tej biografii. Ponadto czas nabiera znaczenia jako metafora transformacji, co uwidacznia się już w tytule książki nawiązującym do cyklu oraz pór roku. Wynikiem takiego przedstawienia własnego życia jest złożona i pełna refleksji autobiografia autorki.

Źródło:

Perspektywy Kultury; 2024, 45, 2; 181-198
2081-1446
2719-8014

Pojawia się w:

Perspektywy Kultury

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce

Skocz do pozycji: 50.

Tytuł:

Mean residual lifetime assessment approach for a multi-state standby system

Autorzy:

Karadayi, Ebru
Funda, Iscioglu

Powiązania:

https://bibliotekanauki.pl/articles/24200825.pdf

Data publikacji:

2023

Wydawca:

Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN

Tematy:

reliability analysis
standby system
multi-state system
mean time to failure
mean residual lifetime

Opis:

In this paper, a new MRL assessment approach for a multi-state standby system is considered. The three-state system is backed up with a binary cold standby unit. Given that the system is at a specific state at time t, obtaining the MRL is worth considering in conducting the maintenance and repair plans of the system. For different degradation rates and time points, MRL results are examined. An HCTMP is considered for the degradation. Therefore, when the system is observed to be at its perfect state, the MRL decrease with an increase in all the failure rates of the system. However, when the system is observed to be at its partial state, the MRL is not affected by the increase in the failure rate pertained to the perfect state. The MRL when the system has known to be failed before time t and backed up with the standby unit increases with the time increase whereas the MRL when the system is at its perfect(or partial) state is constant when time increases. Moreover, cost evaluation of the system is analyzed. The results are supported with numerical examples and graphical representations.

Źródło:

Eksploatacja i Niezawodność; 2023, 25, 2; art. no. 166328
1507-2711

Pojawia się w:

Eksploatacja i Niezawodność

Dostawca treści:

Biblioteka Nauki

/5

Artykuł

Zmień widok

• na półce