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Tytuł:
The technical object reliability evaluation based on the parametric and momentary failures
Autorzy:
Lindstedt, P.
Manerowski, J.
Borowczyk, H.
Powiązania:
https://bibliotekanauki.pl/articles/242760.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
reliability
Weibull function
parametric failure
momentary failure
Opis:
The presented paper concerns with the technical object reliability evaluation based on the parametric and momentary failures during the process of object operating. The real world data observation shows that in the case of high quality technical objects the catastrophic failure events are too rare to the credible evaluation of the object’s reliability. For that reason, the parametric and momentary failures are in the centre of attention in this paper. The set of analysed failures was obtained with the classifiers of the field data provided by the monitoring system (the failure alarms) and the diagnostic system (the functional and technical condition parameters deviation). The changes of the functioning condition potential are used to determine the symptoms of momentary failures and the changes in the potential of the technical condition to determine the symptoms of parametric failures (non-total). The assumed reliability characteristics model has the form R(t) = f(_, Rb(t), Rc(t)), (where: Rb(t) and Rc(t) – the estimators of reliability for parametric and momentary failures, symbol ‘_’ denotes catastrophic failures not covered). For the identification of R (t) as an analytical function, the estimators are computed with the field data. The Weibull distribution function due to its flexibility is often used. Such is the case in this paper. Two parameters a and b known as the scale and the shape parameters are estimated with the computerized procedure realizing least-square method. The presented examples show good fit quality even for small set of data.
Źródło:
Journal of KONES; 2016, 23, 2; 239-246
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fertilization failure and early embryonic mortality as a major cause of reproductive failure in cattle: A review
Autorzy:
Sayid, Ali
Powiązania:
https://bibliotekanauki.pl/articles/1193470.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Bovine
Embryo mortality
Fertilization failure
Reproductive failure
Opis:
Reproductive failure in lactating dairy cows is a significant limitation to the dairy industry. Fertilization failure, Embryonic or fetal losses are major contributors to that limitation. The objective of this review was to determine cause of fertilization failure and early embryonic mortality in cattle. Fertilization failure and embryo mortality is a major cause of economic loss in dairy production systems. Direct effects of fertilization failure and embryo mortality are reflected in reduced conception rates with consequent effects on efficiency, production and profitability. Embryonic loss can be early or late .The major component of embryo loss occurs before day 16 following breeding with emerging evidence of greater losses before day 8 in high producing dairy cows. Late embryo loss causes serious economic losses because it is often recognized too late to rebreed females. Various factors can be a cause for fertilization failure and embryonic mortality. The major cause includes genetic, environmental, endocrine, infectious nutritional factors. More balanced breeding strategies with greater emphasis on fertility, feed intake and energy must be developed. There is a range of easily adoptable management factors that can either directly increase in embryo survival or ameliorate the consequences of low embryo survival rates. The correction of minor deficits in several areas can have a substantial overall effect on herd reproductive performance.
Źródło:
World Scientific News; 2021, 158; 59-71
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mean time to failure for periodic failure rate
Autorzy:
Tanguy, C.
Powiązania:
https://bibliotekanauki.pl/articles/2069664.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
reliability
mean time to failure
periodic failure rate
Opis:
The paper is concerned with the determination of the Mean Time To Failure (MTTF) in configurations where the failure rate is periodical. After solving two configurations exactly, we show that when the period of the failure rate oscillations is small with respect to the average failure rate, the MTTF is essentially given by the inverse of the average failure rate, give or take corrections that can be expressed analytically. This could be helpful in the description of systems the environment of which is subject to changes.
Źródło:
Journal of Polish Safety and Reliability Association; 2009, 2; 361--366
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Likelihood of a failure of a damming structure
Autorzy:
Opyrchał, L.
Hrabowski, W.
Jankowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/241512.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
failure risk
dam
Opis:
Having an analysis of real breakdowns and damages in Polish damming structures as a basis, and assuming the probability of controlling freshet as a unit, one can calculate the probability of failure of a hydro-technical structure, due to failure of the base, the draining system, anti-filtering safety appliances, the body or the abutments. The results obtained af-ford an estimation of failure risk at any moment of the structure's opera-tion and an estimation of the overall failure probability. The calculations were carried out for all dam classes. When the dam's elements are in good condition, the overall failure probability is by one order of magni-tude greater than the probability that a controlling freshet will occur.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 2; 141-146
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on failure rate of the mixture of an exponential distribution and distribution with increasing quadratic failure rate function
Autorzy:
Knopik, L.
Powiązania:
https://bibliotekanauki.pl/articles/206455.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
mixture of distributions
quadratic failure rate function
failure rate function
Opis:
We show that a unimodal failure rate function can be obtained as a mixture of two increasing failure rate functions. Specifically, we study the failure rate of the mixture of an exponential distribution and an IFR (increasing failure rate) distribution with increasing quadratic failure rate function. At the end of the paper we show a numerical example of the modified unimodal failure rate function.
Źródło:
Control and Cybernetics; 2017, 46, 3; 291-297
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for assessing of ship fuel system failures resulting from fuel changeover imposed by environmental requirements
Autorzy:
Kowalak, Przemysław
Myśków, Jarosław
Tuński, Tomasz
Bykowski, Dariusz
Borkowski, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/2038055.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
failure frequency
fuel changeover
fuel system failure
emission control area
Opis:
Environmental regulations instigated the technological and procedural revolution in shipping. One of the challenges has been sulfur emission control areas (SECA) and requirement of fuel changeover. Initially, many reports anticipated that new grades of low sulfur fuels might increase various technical problems in ship operation. This research develops a simple and easy to use method of the failure severity and intensity assessment in relation to fuel changeover. The scale of failure rate in the ship’s fuel system was evaluated qualitatively and quantitively, using developed failure frequency indicator and the time between failure. Based on 77 records of fuel system failures collected on seven ships, it has been found that frequency of failures related to SECA fuel changeover is on average nearly three times higher compared to the rest of sailing time. Their severity did not significantly change, but the structure of failures changed considerably. The method and presented results may help in improvement of ship’s systems design and on-board operational procedures.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 4; 619-626
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards a High Reliable Enforcement of Safety Regulations - A Workflow Meta Data Model and Probabilistic Failure Management Approach
Autorzy:
Thimm, H. H.
Powiązania:
https://bibliotekanauki.pl/articles/136152.pdf
Data publikacji:
2016
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
Environmental Health and Safety
workflow management
workflows
failure detection
failure prediction
Opis:
Today’s companies are able to automate the enforcement of Environmental, Health and Safety (EH&S) duties through the use of workflow management technology. This approach requires to specify activities that are combined to workflow models for EH&S enforcement duties. In order to meet given safety regulations these activities are to be completed correctly and within given deadlines. Otherwise, activity failures emerge which may lead to breaches against safety regulations. A novel domain-specific workflow meta data model is proposed. The model enables a system to detect and predict activity failures through the use of data about the company, failure statistics, and activity proxies. Since the detection and prediction methods are based on the evaluation of constraints specified on EH&S regulations, a system approach is proposed that builds on the integration of a Workflow Management System (WMS) with an EH&S Compliance Information System. Main principles of the failure detection and prediction are described. For EH&S managers the system shall provide insights into the current failure situation. This can help to prevent and mitigate critical situations such as safety enforcement measures that are behind their deadlines. As a result a more reliable enforcement of safety regulations can be achieved.
Źródło:
Transactions on Environment and Electrical Engineering; 2016, 1, 4; 19-28
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The study on algorithm for identification the fatigue crack length of compressor blade based on amplitude-frequency resonant characteristics
Autorzy:
Lichoń, D.
Bednarz, A.
Powiązania:
https://bibliotekanauki.pl/articles/243684.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
fatigue failure
crack length
compressor blade
aircraft engine
failure identification algorithm
Opis:
The article is focused on building the algorithm for identification the fatigue crack length in the first stage of compressor blade of the helicopter PZL-10W turbo-shaft engine. The fatigue wear of compressor blade is a process in which the fatigue crack begins at the structural notch of the working part. For compressor blade, the crack starts at the leading edge and progress along the blade chord. Due to working conditions, the compressor blades are referred to as critical components. The helicopter rotor downwash can easily lift particles form the ground that may cause damages in the compressor section. Aircraft engines are designed so that the rotational speed of impeller remains below the resonant frequency. However, the pulsation of working medium or mechanical vibrations may cause temporary increase of vibration frequency. The appearance of structural notch combined with temporary increase of vibrations may initiate the fatigue failure. The works undertaken at the Department of Aircraft and Aircraft Engines, Rzeszow University of Technology provided a wide spectrum of research data of amplitude-frequency (A-F) characteristics of 1st stage of compressor blade. For different crack lengths, the fatigue tests of resonant frequency and asymmetry of A-F characteristics were acquired. The crack lengths were measured by fluorescent or infrared mapping method. The aim of the article is to develop the numerical method for identification of crack length of compressor blade basing on A-F characteristics. The studies on A-F characteristics in order to find correlations between crack length, resonant frequency and characteristics asymmetry were performed. The next step was to build the algorithm for identification the crack length when only A-F characteristic is known. The article contains the description of researches background, A-F characteristics unique features, algorithm detailed methods of work and sample use of algorithm in identification the crack length.
Źródło:
Journal of KONES; 2017, 24, 4; 157-164
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Factors of Failure in Innovative Business Activities in Sanandaj
Autorzy:
Abdolmalaki, Kazhal
Gholipour, Rahmatolah
Ma’roofi, Fakharadin
Powiązania:
https://bibliotekanauki.pl/articles/1190165.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Innovation
failure of innovative business activities
factors of innovative activity failure
Opis:
The aim of this study was to analyze the reasons affecting the failure of innovative business activities in Sanandaj. The population of this research consisted of 150 managers and experts who did not have innovation in their businesses or had some kind of unsuccessful experience in this field. Mostly, the activities of these businesses were in the field of metal industry, packaging, textile, wood and automotive downstream industries. Among this population a sample of 105 people were chosen by using simple random sampling method. The aim of this study is functional and the data collection was descriptive and correlational. The main tools for collecting data were library resources and standard innovation failure factors questionnaire Wyckoff, and innovation questionnaire, on the basis of Likert scale. Data obtained from the questionnaire were analyzed by using descriptive statistics (mean, percentage, and standard deviation), inferential statistics (Pearson correlation and Structural Equation Modeling (SEM)) and SPSS and AMOS software. Results of the conducted analysis showed that all six factors are effective in the failure of innovative business activities in the city of Sanandaj. The results of Structural Equation Modeling indicated that poor management is more effective than other factors in the failure of activities.
Źródło:
World Scientific News; 2016, 42; 306-316
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation into a Potential Reduction of FMEA Efforts Using Action Priority
Autorzy:
Barsalou, Matthew
Powiązania:
https://bibliotekanauki.pl/articles/2201159.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FMEA
failure modes and effects analysis
risk analysis
failure prevention
quality
Opis:
FMEAs have been prioritized using RPN; however, a new standard has introduced AP for prioritization. This study seeks to determine if the number of required improvement actions increases, decreases, or stays the same when using AP in place of RPN. Statistical software was used to simulate 10,000 combinations of severity, occurrence, and detection. Both AP and RPN were calculated for the 10,000 combinations. Statistical hypothesis testing was performed to determine if there was a difference between RPNs when sorted by AP and to determine if there was a difference in actions required using RPN or AP. There is a statistically significant difference between RPNs when sorted by high, medium, and low AP. Using an RPN threshold equal to or greater than 100 would result in no change in the number of actions required if prioritizing by high and medium, but would result in fewer actions required if only high is used.
Źródło:
Management and Production Engineering Review; 2022, 13, 4; 59--71
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of continuous damage deactivation on yield and failure surfaces
Autorzy:
Cegielski, M.
Ganczarski, A.
Powiązania:
https://bibliotekanauki.pl/articles/387329.pdf
Data publikacji:
2007
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
damage
damage deactivation
failure
Opis:
This article deals with the modeling of the continuous damage deactivation affected yield surfaces of copper and failure surfaces of mortar, from the viewpoint of continuum damage mechanics. The concept of damage deactivation is adapted to Tresca-Guest and Huber-Mises surfaces and two models are presented: the classical discontinuous one, in which microcracks close instantaneously, and the new continuous one, in which they close gradually. The results for both models are compared and verified in order to achieve the best fitting the experimental data. Detailed quantitative and qualitative analysis of obtained solutions confirms the necessity and correctness of an application of the continuous damage deactivation concept.
Źródło:
Acta Mechanica et Automatica; 2007, 1, 2; 15-18
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Engineering availability of aircrafts
Autorzy:
Lewitowicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/242226.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
aircraft
diagnostic
failure
Opis:
Engineering availability and operational readiness of an aircraft are requisites for its ability to operate. After the aircraft has been supplied, both features determine airworthiness of the aircraft, in compliance with the ARC (Airworthiness Review Certificate). Improvement in methods of maintaining the aircraft availability proceeds in compliance with the MSG (Maintenance Steering Group) rules. The paper has been intended to outline the process of maintaining the engineering availability of the aircraft, with account taken of: aircraft maintainability, importance of the engineering diagnostics, and evaluation ratesfor dijferent maintenance patterns. Maintaining technical ability/ airworthiness of an aircraft, ground service of aircrafts, service-friendliness of an aircraft, unfitness and damages to an aircraft, ground diagnostic andprovision equipment for A-380, computer aided verification of an inspection of a front undercarriage (B) of an aircraft (A) and service of the B-787 aircraft (C), percentage for composite material portion in the structure of some aircrafts and helicopters, positions of composite material airframe elements in B-75 7/7 67, B-777, B-787 are presented in the paper.
Źródło:
Journal of KONES; 2009, 16, 2; 255-262
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of fishing basin construction on the behaviour of a footbrdge over the port channel
Autorzy:
Pyrzowski, Ł.
Miśkiewicz, M.
Chróścielewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/260413.pdf
Data publikacji:
2017
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
footbridge
port basin
failure
Opis:
The paper analyses possible causes of failure of the rotating footbridge over the Ustka port channel. In July, 2015, strange behaviour of this object was observed in the form of excessive vibrations of bridge platform suspension rods, with the accompanying acoustic effects. A preliminary geotechnical analysis has revealed that this destructive effect was caused by the nearby construction works, namely construction of a fishing basin and communication routes in the area close to the bridge, which affected the bridge lashing rod foundation settings. Ground vibrations generated by certain construction activities were likely to have direct impact on decreasing the bearing capacity of these rods and increasing the susceptibility od the piles to extraction. After detecting the above problems in bridge operation, its geodetic monitoring was started. The data recorded during this monitoring, along with the results of force measurements in the rods, have made the basis for a series of numerical simulations, performed in the Finite Element Method (FEM) formalism. The bridge structure was analysed in the conditions defined as the emergency state. Extreme efforts of bridge elements and its dynamic characteristics were examined. A possible source of strange behaviour of the footbridge during its operation which was recognised during these simulations was the coincidence of the global natural frequency of the entire bridge structure with local vibrations of suspension rods, at the frequency approximately equal to 1 Hz. This situation was likely to lead to the appearance of the so-called internal resonance phenomenon. As a final conclusion of the research, recommendations were formulated on possible object oriented corrective actions.
Źródło:
Polish Maritime Research; 2017, S 1; 182-187
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Postoperative Acute Respiratory Failure In Patients Treated Surgically For Goiters
Autorzy:
Buła, Grzegorz
Mucha, Ryszard
Paliga, Michał
Truchanowski, Witold
Gawrychowski, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1395678.pdf
Data publikacji:
2015-07-01
Wydawca:
Index Copernicus International
Tematy:
goiter
acute respiratory failure
Opis:
The aim of the study was to present a clinical picture, treatment and prognosis regarding patients who developed acute respiratory failure (ARF) while treated surgically for a goiter. Material and methods. A total of 3810 patients were treated for goiters between 2008 to 2013. Symptoms of postoperative ARF were recognized in 39 (1%) patients. Results. Symptoms of postoperative ARF were a postoperative hemorrhage in 31 (79.4%), lymphorrhagia in 1 (2.6%), bilateral paralysis of recurrent laryngeal nerves in 6 (15.4%) and acute circulatory – respiratory failure in 1 (2.6%). Postoperative hemorrhage appeared in 19 patients operated for nodular goiter, 4 with a retrosternal nodular goiter, 1x nontoxic recurrent retrosternal nodular goiter, 1x toxic recurrent retrosternal goiter nodular goiter, 2x Graves'goiter and 4x with malignant goiter. The cause of hemorrhage was parenchymal bleeding from the stumps and / or short neck muscles (29x), arterial bleeding (1x) and bleeding into the subcutaneous tissue (1x). Massive lymphorrhagia appeared as a result of damage to the thoracic duct after total thyroidectomy due to papillary thyroid carcinoma with cervical lymph node dissection on the left side. All patients who were diagnosed with bilateral paralysis of RLN, tracheostomy was performed. Of all 39 patients who underwent surgery two died – one in 6 days after surgery due to myocardial infarction, and another as a result of micropulmonary embolism and acute circulatory – respiratory failure in 18 hours after surgery. Conclusions. 1. The most frequent causes of acute respiratory failure in postoperative period are a hemorrhage from the operation site and bilateral paralysis of recurrent laryngeal nerves. 2. Acute postoperative respiratory failure is an indication for postoperative wound revision
Źródło:
Polish Journal of Surgery; 2015, 87, 7; 331-335
0032-373X
2299-2847
Pojawia się w:
Polish Journal of Surgery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czy możliwa jest budowa teorii moralnej zawodności rynku?
Is it possible to build a moral theory of market failure?
Autorzy:
Rogowski, Robert
Powiązania:
https://bibliotekanauki.pl/articles/653177.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
market
person
market failure
Opis:
Economics and ethics are practical sciences. The common research subject of both sciences is man. Economics is looking for an answer to the question of how to manage in business life. Ethics looks for the answer to the question of how to live. Because man is a person, his value brings consequences for all areas of human activity. This also applies to the market. The market is one of the foundations of economic life and is a great good for people and societies. The market is defined in different ways. It is worth comprehensively describing what the market is, emphasizing its personal character. In economics, attention is paid to market failure, understood mostly as the ineffectiveness of management (deviation from the model market, which is perfectly competitive). The negative impact of the market on society is also identified. Although moral aspects are increasingly taken into account in the concept of market failure, there is no general theory that attempts to capture market in moral aspects. Therefore, it is worth asking whether such a theory is possible. The construction of the moral theory of market failure can be a reference point to the analysis of market practices and institutional conditions from an ethical point of view.
Źródło:
Annales. Etyka w Życiu Gospodarczym; 2019, 22, 2; 25-39
1899-2226
2353-4869
Pojawia się w:
Annales. Etyka w Życiu Gospodarczym
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applying the Anticipatory Failure Determination at a Very Early Stage of a System’s Development: Overview and Case Study
Autorzy:
Chybowski, L.
Gawdzińska, K.
Souchkov, V.
Powiązania:
https://bibliotekanauki.pl/articles/2065020.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
complex technical system
anticipatory failure determination
AFD
anticipatory failure analysis
AFA
failure prediction
Theory of Inventing Problem Solving
TRIZ
Opis:
Anticipatory Failure Determination (AFD) is a tool used in the TRIZ (Theory of Inventive Problem Solving) methodology. This article introduces its concept and describes the process of AFD in different versions of the method. The article presents the application of the AFD method at a very early state of a system’s development, i.e. its concept formulation stage, which corresponds to a technology readiness level (TRL) equal to 2. The system under analysis is a set of devices used to reduce displacement ship hull resistance. The system was modelled using functional analysis. An analysis of system resources was then carried out. Possible direct, indirect, and accident-related failures were identified. A multi-criteria analysis of the causes of system failures was conducted from which the top 10 potential failures were selected. Observations were made on the applicability of AFD in respect to systems not yet implemented.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2018, 1, 1; 205--215
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wybrane aspekty kosztów oraz awaryjności przewodów przykładowego systemu wodociągowego
Selected Issues of Costs and Failure of Pipes in an Exemplary Water Supply System
Autorzy:
Pietrucha-Urbanik, K.
Studziński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1817993.pdf
Data publikacji:
2016
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
sieć wodociągowa
awaryjność
koszty
intensywność uszkodzeń
water network
failure
cost
failure rate
Opis:
The aim of the study is to analyze cost and failures of water pipes. The analysis was conducted on the basis of operational data of the failure of the water supply network pipes, obtained from the water supply company. In the analysis, the indicator of failure rate for different types of water pipes (mains, distributional pipes and water supply connections) was accounted for. The analysis of the failure of water supply pipes in connection to the diameter, age and material was presented in the paper. The analysis can be applied in operational practice in water companies, particularly in the analysis related to the costs of pipe repairs, which consists in estimating the cost of repair work. Material composition of water supply system constitutes mainly PE and steel pipes. The new pipes are built mainly of PE. The regular replacement of cast iron pipes is noted, because of their high failure rate, which indicates that these pipes have reached the end of life technology. The obtained failure rate values were referred to the ones recommended by European criteria, as it should not exceed 0,3 failure/km a for mains, 0,5 failure/km a for distributional pipes and 1,0 failure/km a for water supply connections. In the case of distributional pipes, the failure rate exceeds the criteria and in the case of water supply connections and distributional pipes, the observed values are lower than the limit value. Repair of mains constitute 39% of all costs due to the large diameter pipes and the associated higher cost of the material. Lower total cost is related to failures, which occur on distributional pipes (23.8%) and fittings of water supply network (3.7%). The total cost of operating employees constitutes the highest of all costs. The costs incurred for materials are lower of 9.2%. Labour costs are higher than the costs of equipment by 3.6%. The data can be complementary to the national database in this area and allow to carry out a satisfactory assessment of the water supply network, taking into account both the network failure rate, as well as the tendency of changes in material supply network pipes. Despite numerous studies in the field of water supply system failure, there is still a need of conducting further study, such situation is affected by the ongoing changes in the age and structure of water supply networks. The collected data and conducted analysis can be one of the decisive indicators for the policy of operation of water supply systems.
Źródło:
Rocznik Ochrona Środowiska; 2016, Tom 18, cz. 2; 616-627
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test Signal Design for Failure Detection: a Linear Programming Approach
Autorzy:
Scola, H. R.
Nikoukhah, R.
Delebecque, F.
Powiązania:
https://bibliotekanauki.pl/articles/908093.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
automatyka
failure detection
large scale programming
failure isolation
bounded perturbations
active detection
Opis:
A new methodology for the design of filters that permits failure detection and isolation of dynamic systems is presented. Assuming that the normal and the faulty behavior of a process can be modeled by two linear systems subject to inequality bounded perturbations, a method for the on-line implementation of a test signal, guaranteeing failure detection, is proposed. To improve the fault detectability of the dynamic process, appropriate test signals are injected into the system. All the computations required by the proposed method are implemented as the solution of large sparse linear optimization problems. A simple numerical example is given to illustrate the proposed procedure.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2003, 13, 4; 515-526
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Awaryjność ścianowych kombajnów węglowych na przykładzie KSW-475-/BP i KSW-460/NZ
Failure frequency of the longwall coal shearers machine with regard to KSW-475/2BP and KSW-460/NZ
Autorzy:
Profaska, M.
Bielak, M.
Powiązania:
https://bibliotekanauki.pl/articles/113524.pdf
Data publikacji:
2016
Wydawca:
STE GROUP
Tematy:
kombajn ścianowy
identyfikacja uszkodzeń
diagnozowanie uszkodzeń
longwall coal shearer
failure detection
failure diagnosis
Opis:
W publikacji przedstawiono uszkodzenia ścianowych kombajnów węglowych KSW 475/2BP oraz KSW-460/NZ pracujących w porównywalnych warunkach górniczo-geologicznych. Podjęto problematykę związaną z uszkodzeniami mechanicznymi oraz awariami układu hydraulicznego, najciekawsze z nich zostały przeanalizowane szczegółowo. Analizie poddane zostaną również sposoby diagnozowania, usuwania oraz przyczyny powstawania awarii.
This article presents damages of longwall coal shearers: KSW 475/2BP and KSW-460/NZ working in comparable geological and mining conditions. The following paper reports issue of mechanical failures and hydraulic system problems, the most interesting of them were elaborated. What was also analyzed were methods of diagnosing and troubleshooting and the causes of failures.
Źródło:
Systemy Wspomagania w Inżynierii Produkcji; 2016, 2 (14); 278-286
2391-9361
Pojawia się w:
Systemy Wspomagania w Inżynierii Produkcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Device Failure in the Mechanical Production Plant
Autorzy:
Sitko, J.
Mikuš, R.
Božek, P.
Powiązania:
https://bibliotekanauki.pl/articles/2064943.pdf
Data publikacji:
2018
Wydawca:
STE GROUP
Tematy:
plant
failure
analysis
repair
quality
Opis:
The article evaluates the failure rate of devices in the Mechanical Processing Plant using a traditional quality tool, the Pareto-Lorenzo diagram. A comparative analysis of failure rates was performed, recorded in repair, inspection and maintenance card. Then, changes were proposed in order to reduce failure rates and earlier detection of equipment malfunctions. In order to analyze the failure rate of grain washer equipment during thick coal preparation process, one quality management tools was used - the Pareto-Lorenzo diagram. In this case, it is important to assess the mechanical failure of devices, and demonstrating which devices generate most repairs. Based on materials made available by the mine, such as: Repair, inspection and maintenance cards, Device cards, DTR documentation. Quantitative and qualitative assessment the most frequently occurring mechanical failures during operation of devices in process enrichment of coarse sizes was carried out. An attempt was made to assess failure rate of devices on a grain washer. A comparative analysis of failure rates in 2015-2017 recorded in the repair, inspection and maintenance card was carried out. Then, changes were proposed to stand, in order reduce failure rates, and earlier detection equipment malfunctions.
Źródło:
Multidisciplinary Aspects of Production Engineering; 2018, 1, 1; 93--99
2545-2827
Pojawia się w:
Multidisciplinary Aspects of Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The use of the FMEA method in the analysis and assessment of technical systems safety
Autorzy:
Tchórzewska-Cieślak, B.
Pietrucha-Urbanik, K.
Szpak, D.
Powiązania:
https://bibliotekanauki.pl/articles/2068740.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
FMEA
risk
safety
failure analysis
Opis:
The analysis and assessment of the protection of technical system was performed using the FMEA method (Failure Mode and Effect Analysis). The FMEA method allows the product or process to be analysed, to identify weak points, and then introduce corrections and new solutions to eliminate sources of undesirable events. The developed methodology was presented on the example.
Źródło:
Journal of Polish Safety and Reliability Association; 2018, 9, 3; 95--100
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Percepcja ryzyka niepowodzenia zawodowego wśród studentów
Perception the Risk of Professional Failure Among Students
Autorzy:
Wódz, Jacek
Szczepańska-Woszczyna, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/920307.pdf
Data publikacji:
2018-12-15
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
luck
failure
student
occupation job
Opis:
The author reflects on the risk of professional failure among students. He believes that in this case we have a vague definition of professional failure. He indicates both causes, those independent of humans and those related to their own actions or negligence. Then he refers to the category of occupation and its place in times of uncertainty. Pointing to the factors determining the perception of the risk of professional failure, he emphasizes the role of the University, which gives support to its students in the process of their professional risk assessment.
Źródło:
Studia Edukacyjne; 2018, 51; 287-308
1233-6688
Pojawia się w:
Studia Edukacyjne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Significance of education and self-management support for patients with chronic heart failure in family physician practice
Autorzy:
Korzh, Oleksii
Krasnokutskiy, Sergiy
Powiązania:
https://bibliotekanauki.pl/articles/551603.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Przyjaciół Medycyny Rodzinnej i Lekarzy Rodzinnych
Tematy:
education
heart failure
self-management.
Źródło:
Family Medicine & Primary Care Review; 2016, 4; 432-436
1734-3402
Pojawia się w:
Family Medicine & Primary Care Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of semiautonomy mode for ibis mobile robot with analysis of sensor failure tolerance
Autorzy:
Bartoszek, J.
Trojnacki, M.
Bigaj, P.
Powiązania:
https://bibliotekanauki.pl/articles/384614.pdf
Data publikacji:
2011
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
sensor failure
mobile robot
semiautonomy
Opis:
This work is concerned on sensitivity analysis of semiautonomy algorithm of mobile combat robot to environmental sensors' damage. The construction of the robot, semiautonomy algorithm and used sensors have been described. This algorithm takes into account environmental sensors’ damage. Simulation research results of semiautonomy algorithm using Matlab/Simulink package was presented. This research was performed for normal environmental sensors’ operation and for selected sensors' damage. On that basis, sensitivity of semiautonomy algorithm to selected environmental sensors damage was tested.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2011, 5, 4; 3-10
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of costs of repairs of undesirable events occurring in a municipal bus transportation system
Autorzy:
Bojar, P.
Woropay, M.
Migawa, K.
Szubartowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/247304.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport system
collision
devastation
failure
Opis:
Systems of public transport carry out their tasks on the territory of a given town and in the suburbs performing the same functions as in towns. A distinctive feature of this type of system is performance of its task for twenty four hours, in different traffic intensity conditions over an assigned administrative area. This type of variables has a large influence on occurrence of undesirable events (failure of vehicles and their devastation, collision and accidents). In the work, an attempt of identification of undesirable events occurring in the analyzed transport system has been made. Moreover, an analysis has been made which covers one day of the week, time of the day and weather conditions in which particular events took place. Another aspect of the work was to make an analysis of the vehicle driver's age, job experience and a given hour of work on the day of the event occurrence. Obtainment of such data allowed demonstrating the structure of events according to the criterion of the event type, and costs connected with bringing the damaged transport means to the state of serviceability. The obtained results of experimental tests provide a basis for taking rational decisions by decision makers employed in a given system. These decisions are supposed to reduce the number of undesirable events occurrence and costs connected with them.
Źródło:
Journal of KONES; 2011, 18, 4; 19-24
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expression profile of circulating microRNAs in patients with ischemic heart failure with moderately reduced left ventricular ejection fraction – pilot study
Autorzy:
Kaufmann, Damian
Daniłowicz-Szymanowicz, Ludmiła
Sakowicz-Burkiewicz, Monika
Szwoch, Małgorzata
Pawełczyk, Tadeusz
Raczak, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/895765.pdf
Data publikacji:
2019-02-05
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
heart failure
circulating microRNAs
biomarkers
Opis:
Introduction: Heart failure (HF) is a growing global pandemic that affects millions of people around the world. Despite the progress in medicine, diagnosis and treatment of HF remains problematic. Recently, noncoding micro ribonucleic acids called miRNAs have become significant in the diagnosis and stratification of HF risk. Aim: The aim of this study was the attempt to identify the profile of circulating miRNAs specific for ischemic HF with moderately reduced left ventricular ejection fraction (HFmrEF). Methods and Results: A number of changes in the miRNA profile can characterise patients with ischemic HFmrEF. This is a pilot study before further research on a larger group of patients. Conclusions: Using the quantitative reverse transcription-polymerase chain reaction (qRT-PCR), serum levels of 84 miRNA were measured and compared between a patient with ischemic HFmrEF and a healthy volunteer. Analysis reveals a down-regulation of let-7f-5p and miR-1-3p, as well as up-regulation of miR-100-5p, miR-10b-5p, miR-125a-5p, miR-140-5p, miR-144-3p, miR-149-5p, miR-15b-5p, miR-183-5p, miR-208b-3p, miR-224-5p, miR-26b-5p, miR-27b-3p, miR-302a-3p, miR-320a, miR-7-5p, miR-99a-5p.
Źródło:
European Journal of Translational and Clinical Medicine; 2018, 1, 2; 53-57
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prolonged renal failure in the course of atypical ethylene glycol intoxication
Autorzy:
Liberek, Tomasz
Śliwarska, Julita
Czurak, Krzysztof
Perkowska-Ptasińska, Agnieszka
Weber, Ewa
Rutkowski, Bolesław
Powiązania:
https://bibliotekanauki.pl/articles/1039462.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
ethylene glycol
intoxication
renal failure
Opis:
Ethylene glycol poisoning is not an uncommon cause of an acute renal injury. In this paper we present case of prolonged renal failure in the course of ethylene glycol intoxication. Due to the low dose of ingested ethylene glycol and concomitant ethanol consumption, the neurodepressive phase of the intoxication was rather mild and patient presented to the hospital on the ninth day after poisoning with established renal failure. The diagnosis of the specific cause of renal injury was facilitated by the renal biopsy.
Źródło:
Acta Biochimica Polonica; 2013, 60, 4; 661-663
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of selected strain-based failure criteria on ship structure damage resulting from a collision with an offshore wind turbine monopile
Autorzy:
Niklas, Karol
Bera, Alicja
Powiązania:
https://bibliotekanauki.pl/articles/2033234.pdf
Data publikacji:
2021
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship
collision
monopile
failure
crashworthiness
Opis:
Offshore wind farms are developing well all over the world, providing green energy from renewable sources. The evaluation of possible consequences of a collision involves Finite Element computer simulations. The goal of this paper was to analyse the influence of selected strain-based failure criteria on ship damage resulting from a collision with an offshore wind turbine monopile. The case of a collision between an offshore supply vessel and a monopile-type support structure was examined. The results imply that simulation assumptions, especially the failure criteria, are very important. It was found that, using the strain failure criteria according to the minimum values required by the design rules, can lead to an underestimation of the ship damage by as much as 6 times, for the length of the hull plate, and 9 times, for the area of the ship hull opening. Instead, the adjusted formula should be used, taking into account both the FE element size and the shell thickness. The influence of the non-linear representation of the stress-strain curve was also pointed out. Moreover, a significant influence of the selected steel grade on collision damages was found.
Źródło:
Polish Maritime Research; 2021, 4; 42-52
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A topological model to assess networks connectivity and reliability
Autorzy:
Eid, M.
Hami-EL, A.
Souza de Cursi, E.
Powiązania:
https://bibliotekanauki.pl/articles/2069197.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
network
connectivity
failure
reliability
availability
Opis:
The acceleration of the interconnectivity of networks of all sorts brings to the front scene the issue of networks performance measure. Recently, one observed an accelerating course towards quantitative probabilistic models to describe and assess networks’ Connectivity, as being the main vector of performance. However, modelling realistic networks is still far from being satisfactorily achieved using quantitative probabilistic models. On the other hand, little room had been lift to exploring the potential of topological models to develop qualitative and semi- quantitative models in order to assess networks connectivity. In this paper, we are exploring the potential of the topological modelling. The proposed model is based on describing the nodepair connectivity using binary scalars of different orders (tensors). Preliminary results of our explorations sounded very promoting.
Źródło:
Journal of Polish Safety and Reliability Association; 2013, 4, 2; 167--178
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods for identifying threats of critical infrastructure systems within Baltic Sea region
Autorzy:
Tchórzewska-Cieślak, Barbara
Pietrucha-Urbanik, Katarzyna
Szpak, Dawid
Powiązania:
https://bibliotekanauki.pl/articles/2068699.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
failure
system safety
safety management
risk
security
threats
FMEA
safety
failure analysis
Bayes network
Opis:
In the analysis of the operation of critical infrastructure systems it is important to perform the analysis of the safety of the operation. The daily operation of such systems is inherently associated with the occurrence of various types of random undesirable events. Therefore, in the paper the matrix and logical trees methods used in the analysis of the risk of threats in critical infrastructure systems within the Baltic Sea, were presented. The analysis and assessment of the protection of technical system was performed using the FMEA method (Failure Mode and Effect Analysis). As to analyse the cause and effect of undesirable events the method of Bayes' theorem and Java Bayes program were implemented, which allows to identify the probability of the event occurrence.
Źródło:
Journal of Polish Safety and Reliability Association; 2019, 10, 1; 149--166
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Łożyskowanie wałów przekładni turbin wiatrowych – problemy eksploatacyjne
Bearing systems of wind turbines – maintenance problems
Autorzy:
Wasilczuk, M.
Gawarkiewicz, R.
Libera, M.
Wasilczuk, F.
Kinal, G.
Powiązania:
https://bibliotekanauki.pl/articles/189693.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
turbina wiatrowa
uszkodzenia przekładni
uszkodzenia łożysk
wind turbine
roller element bearing failure
gear failure
Opis:
W praktyce eksploatacyjnej turbin wiatrowych o tradycyjnej konstrukcji (przekładniowych) obserwowana jest duża awaryjność przekładni, a zwłaszcza łożysk tocznych szybkoobrotowych wałów przekładni. W Polsce na zlecenie właściciela dużej farmy wiatrowej, firmy Energa Wytwarzanie S.A., Politechnika Gdańska we współpracy z Politechniką Poznańską i Akademią Górniczo-Hutniczą podjęły badania mające na celu diagnozowanie przyczyn uszkodzeń oraz sformułowanie zaleceń obniżających koszty eksploatacji. W pracy przedstawione są pierwsze ustalenia wynikające z analizy istniejących danych z eksploatacji turbin wiatrowych o mocy 1,5 MW.
In operation of wind turbines of conventional design (with gear), a high failure rate of gears, especially the cylindrical roller bearings of the high-speed shafts, are observed. In Poland, the owner of a large wind farm Energa Wytwarzanie S.A. initiated a research program aimed at diagnosing the roots of failures and propose recommendations to lower operating costs, In the paper, the first findings from the analysis of existing data from the operation of wind turbines of 1.5 MW carried out by Gdańsk University of Technology in cooperation with Poznań University of Technology and AGH University of Science and Technology are presented.
Źródło:
Tribologia; 2015, 4; 187-198
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Awaria budynku zabytkowego w wyniku realizacji prac budowlanych w sąsiedztwie
The failure of the listed building as result of the realization of construction work in the neighbourhood
Autorzy:
Błaszczyński, T.
Powiązania:
https://bibliotekanauki.pl/articles/390099.pdf
Data publikacji:
2016
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
budynek zabytkowy
awaria
stan awaryjny
prace budowlane
listed building
failure
failure state
construction work
Opis:
W związku z projektowaną budową wielofunkcyjnego budynku biurowo-usługowego w Poznaniu, a także w związku z przewidywaną modernizacją technicznej infrastruktury podziemnej, powinna zachodzić potrzeba inwentaryzacji i oceny stanu technicznego istniejących obiektów sąsiednich. Także zgodnie z wymogami sformułowanymi w decyzji o warunkach zabudowy oraz zgodnie z uwagami zawartymi we wcześniejszych ekspertyzach, powinno się wykonać te prace. Inwentaryzacja i ocena stanu technicznego istniejących obiektów sąsiednich powinna być wykonana pod kątem wpływu budowy na nie i przeciwdziałania ewentualnym skutkom związanym z realizacją projektowanych robót w sąsiedztwie. Niestety inwestor takich prac nie podjął, a realizowane prace doprowadziły do stanu awaryjnego w analizowanym budynku zabytkowym.
In connection with new designed construction of retail-office building in Poznań, and also in connection with the foreseen modernization of the technical underground infrastructure, it should happened the necessity of inventory and the estimation of the technical state of existing neighbouring objects. Also formally with formulated in the decision land development and in accordance with the references contained in earlier expertises, these works should be execute. The inventory and the estimation of the technical state of existing neighbouring objects should be performed in the connection with the influence of new construction in the vicinity on these objects and with counteractions to possible results connected with the realization of designed works in the neighbourhood. Unfortunately the investor did not undertake such works, and realized works brought to the failure state in analysed listed building.
Źródło:
Budownictwo i Architektura; 2016, 15, 2; 79-86
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interval-valued intuitionistic fuzzy failure modes and effect analysis of the system failure risk estimation
Autorzy:
Nguyen, H.
Powiązania:
https://bibliotekanauki.pl/articles/243789.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
interval-valued intuitionistic fuzzy sets
failure modes
effects analysis
system failure risk estimation
expert judgment
Opis:
Among the risk assessment methods, failure modes and effects analysis (FMEA) is a popular, widely used engineering technique in many areas. It can be used to identify and eliminate known or potential failure modes to enhance reliability and safety of complex systems. In practice, risk estimations encounter difficulties connected with shortage of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, the decision makers might be unable to assign the exact values to the evaluation judgments due to his/her limited knowledge. In other words, there is a certain degree of hesitancy in human cognition and his/her judgment, who may have insufficient knowledge of the problem domain or uncertainty in assigning the evaluation values to the objects considered. In order to deal with ambiguity and uncertainty in the imperfect information, there have been recently proposed many various such theories as fuzzy sets, interval-valued fuzzy sets, type-2 fuzzy sets, hesitant sets, grey sets, rough sets and intuitionistic fuzzy sets. They have drawn more and more attention of scholars and been adopted in many applications This article addresses the Atanassov’s interval-valued intuitionistic fuzzy sets and FMEA methods in the risk estimation of the system failures based on the expert judgments.
Źródło:
Journal of KONES; 2017, 24, 2; 159-166
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza kosztów materiałów użytych do usuwania awarii przewodów wodociągowych
Analysis of Material Costs Used for Failure Removal of Water Supply Networks
Autorzy:
Studziński, A.
Pietrucha-Urbanik, K.
Powiązania:
https://bibliotekanauki.pl/articles/1813737.pdf
Data publikacji:
2018
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
sieć wodociągowa
awaryjność
koszty usuwania awarii
materiały
water network
failure
cost of failure removal
materials
Opis:
Koszty usuwania awarii przewodów można rozdzielić na koszty materiałów, sprzętu oraz robocizny. Opracowanie dotyczy analizy kosztów materiałów związanych z usuwaniem awarii rurociągów wodociągowych. Podstawą pracy są dane eksploatacyjne zebrane podczas usuwania 302 awarii przewodów w mieście o liczbie mieszkańców przekraczającej 100 tys. Zauważono zależność kosztów materiałów od średnicy oraz materiału przewodu, które rosną wraz ze wzrostem średnicy. Zróżnicowanie kosztów jest również wynikiem lokalizacji przewodu – tam gdzie wymagany jest wysoki stopień zagęszczenia gruntu przeprowadza się jego wymianę, co skutkuje wzrostem kosztów materiałów, przewody prowadzone w pasie drogowym charakteryzuje więc wyższy koszt materiałów. W badanym systemie zaopatrzenia w wodę średni koszt materiałów użytych do naprawy awarii wyniósł 517 zł (poziom cen 2015 rok), był niższy od kosztów robocizny, które wyniosły 800 zł. W 47% awarii konieczne było zastosowanie kruszyw, co przeciętnie podniosło koszt materiałów w tym przypadku o 320 zł.
Costs of pipe failure removal cables can be separated into the cost of materials, equipment and labor. The paper concerns the analysis of material costs associated with failure removal of water supply pipelines. The basis of the work constitutes operational data collected during the removal of 302 failures on pipes in city with a population exceeding 100 thousand. The dependence of material costs and the pipe diameter, which grow with increasing diameter, is noted. Cost diversification is also the result of the location of the pipe – where a high degree of soil compaction is required, the exchange is performed, resulting in material costs increase, so the pipes in the lane are characterized by higher material costs. In the analyzed water supply system average cost of materials used to repair the failure amounted to 517 zł (price level for 2015 years) and was lower than labor costs, which amounted to 800 zł. In 47% of the failure it was necessary to use aggregates, which on average increased the cost of materials in this case by 320 zł.
Źródło:
Rocznik Ochrona Środowiska; 2018, Tom 20, cz. 2; 1453-1464
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Directional change and windup phenomena in LQR-controlled systems with actuator failure
Autorzy:
Horla, D.
Powiązania:
https://bibliotekanauki.pl/articles/141455.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
directional change
windup phenomenon
actuator failure
Opis:
The paper presents a phenomenon of directional change in the case of a LQR controller applied to multivariable plants with amplitude and rate constraints imposed on the control vector, as well as the impact of the latter on control performance, with the indirect observation of the windup phenomenon effect via frequency of consecutive resaturations. The interplay of directional change of the computed control vector with control performance has been thoroughly investigated, and it is a result of the presence of constraints imposed on the applied control vector for different ratios of the number of control inputs to plant outputs. The impact of the directional change phenomenon on the control performance (and also on the windup phenomenon) has been defined, stating that performance deterioration is not tightly coupled with preservation of direction of the computed control vector. This conjecture has been supported by numerous simulation results for different types of plants with different LQR controller parameters.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 345--359
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The airway obstruction - important abrupt condition for pediatrics
Autorzy:
Tomaszewski, M.
Banakiewicz, K.
Jajko, K.
Szypowski, R.
Zieliński, P.
Zalewski, G.
Spisacka, S.
Olchowik, G.
Powiązania:
https://bibliotekanauki.pl/articles/2052449.pdf
Data publikacji:
2015
Wydawca:
Akademia Bialska Nauk Stosowanych im. Jana Pawła II w Białej Podlaskiej
Tematy:
airway obstruction
hypoxemia
hypercapnia
respiratory failure
Opis:
The ability of fast response in case of increasing health problems of a child which lead directly to life-threatening situations is a necessary condition for creating opportunity of child’s survival until it will be transported to intensive care unit, where it will be provided with care by a specialist. In case of healthy children the most common cause of acute respiratory failure is obstruction of upper respiratory tract. There is an enormous variety of causes of upper airway obstruction, but the most important are the result of congenital defects, acute inflammation, anaphylactic reactions, foreign body aspiration and injuries. Consequence of the hypoventilation resulting from significant impediment of airflow through the obstructed airways is impaired gas exchange in the lungs. This leads to the increasing hypoxemia (PaO 2 <60 mmHg) and hypercapnia (PaCO2> 45 mmHg). This condition is called the total respiratory failure. The persistence of hypoventilation leads to hypoxia of vital organs (heart muscle, brain), increased anaerobic metabolism, acidosis, and inevitably to cardiac arrest as a result of homeostasis disorders. Respiratory failure is defined as acute when developing suddenly and is potentially reversible. We can find such a situation in the fast-increasing stenosis of the larynx. Symptoms of severe dyspnoea occur in a short time, but can be interrupted by an effective airway patency. Acute respiratory failure is a state of direct threat to life, which is why it is crucial to give a prompt aid to the sick child. The aim of this paper is to discuss the signs and symptoms, knowledge of which is essential for rapid identification and initial differentiation of the causes of acute upper airway obstruction in children. The principles of first-aid for children with acute respiratory failure and above all the description of life-saving procedures will be presented.
Źródło:
Health Problems of Civilization; 2015, 09, 1; 18-22
2353-6942
2354-0265
Pojawia się w:
Health Problems of Civilization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intrauterine fetal demise and late motherhood - a case report
Autorzy:
Kiersnowska, I.
Baranowska, B.
Bączek, G.
Węgrzyn, P.
Powiązania:
https://bibliotekanauki.pl/articles/2088266.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Opolski. Instytut Nauk o Zdrowiu
Tematy:
fetal death
late motherhood
obstetric failure
Opis:
Background: Intrauterine fetal death is a potential risk in each stage of pregnancy, regardless of the mother’s age. In Poland in 2015, new standards of care were introduced for women with obstetric failure. Aim of the study: This study aimed to analyze intrauterine fetal demise in the context of late motherhood. Material and methods: Medical documentation and a semi-structured interview were used. Case report: A 41-year old primipara in 37 weeks of pregnancy, who had not felt fetal movements for 2 days, was diagnosed with intrauterine fetal demise. The pregnancy was uneventful before, but the patient suffered from hypertension and severe obesity. As a result of induced labor, a male neonate weighing 2260 g, 49 cm long, with no signs of vital functions, was born. After the birth, it was established that the child died due to an umbilical cord accident. The mother was given the appropriate time to see the child for the last time. During delivery and hospitalization, the patient’s privacy was ensured, she was isolated from other women in labor and new mothers and was assisted by her family. During the hospital stay, the patient was under the care of the obstetrician, midwife and clinical psychologist. She was discharged from the hospital after 6 days. Conclusions: The loss of a child is one of the most traumatic experiences for a mother, particularly in the case of older mothers. A woman’s fertility declines with age, so getting pregnant again might prove extremely difficult for older women.
Źródło:
Medical Science Pulse; 2019, 13, 3; 35-38
2544-1558
2544-1620
Pojawia się w:
Medical Science Pulse
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of liquefaction potential for loose minefill slopes
Autorzy:
Kudella, P.
Powiązania:
https://bibliotekanauki.pl/articles/1954561.pdf
Data publikacji:
2022-02-07
Wydawca:
Politechnika Gdańska
Tematy:
liquefaction
granular materials
hypoplasticity
instability
failure
Opis:
Uncompacted embankments of certain fine sands exhibit a spontaneous liquefaction potential, which cannot be evaluated basing on undrained shear strength alone. A novel procedure for stability analysis has been developed, basing on Hill's stability criterion and a hypoplastic constitutive law. With given relative densities, assumed initial stress states and variations of perturbation directions, stability or instability of slope sections can be assessed. Catastrophic landslides observed in the past could thus be explained.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2000, 4, 3; 439-451
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of methods for identifying threats including the critical infrastructure systems within the Baltic Sea
Autorzy:
Tchórzewska-Cieślak, B.
Pietrucha-Urbanik, K.
Szpak, D.
Powiązania:
https://bibliotekanauki.pl/articles/2068908.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
failure
system safety
safety management
threats
Opis:
In the analysis of the operation of critical infrastructure systems it is important to perform the analysis of the safety of the operation. The daily operation of such systems is inherently associated with the occurrence of various types of random undesirable events. Therefore, in the paper the methods used in the analysis of the risk of threats in critical infrastructure systems within the Baltic Sea, were presented.
Źródło:
Journal of Polish Safety and Reliability Association; 2017, 8, 1; 139--148
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developing procedures for hazard identification
Autorzy:
Tchórzewska-Cieślak, B.
Pietrucha-Urbanik, K.
Szpak, D.
Powiązania:
https://bibliotekanauki.pl/articles/2069083.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
failure
system safety
safety management
threats
Opis:
The reliable operation of critical infrastructure has a direct impact on the energy security of country. Due to the complexity and vastness of such system it is exposed to various types of events that could lead to failure. These risks may result directly from the operation and also be the result of external factors. Especially dangerous are the undesirable events with incidental character or unlikely events that constitute a serious threat to people and the environment and resulting in significant loss.
Źródło:
Journal of Polish Safety and Reliability Association; 2016, 7, 1; 209--216
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of performing Design FMEA on electronic circuit diagrams
Autorzy:
Karcz, R.
Powiązania:
https://bibliotekanauki.pl/articles/2069239.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Morski w Gdyni. Polskie Towarzystwo Bezpieczeństwa i Niezawodności
Tematy:
electronic circuit analysis
failure mode
TTAA
Opis:
Existing method of performing FMEA for electronic diagrams is time consuming task. For complex systems analysis of every single component failure mode and its effect deeply involves design team and blocks resources availability for long time. Method presented in this paper allows effective analysis of design failure modes using FMEA approach carrying so called Time to Acceptable Analysis (TTAA) constraint.
Źródło:
Journal of Polish Safety and Reliability Association; 2015, 6, 1; 125--128
2084-5316
Pojawia się w:
Journal of Polish Safety and Reliability Association
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On some approaches to the stress-state determination in layered cracked plates
Autorzy:
Delyavsky, M.
Opanasovich, V.
Olejniczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/279462.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
layered plates
crack
stress distribution
failure
Opis:
A survey of approaches to determination of the stress-state in layered plates with the cracks located symmetrically about their thickeness is presented. The plate is subject to a complex biaxial loading; i.e., tension - shear or bending - torsion, while the crack of length 2a is unloaded. The plate layers can be homogeneous or non-homogeneous, rigid to shear or yielding due to shear. To study such plates the following mathematical models are employed: the plates rigid to shear are considered within the framework of classical plate theory, while those yielding due to shear are within the scope of Timoshenko's theory. The asymptotic formulae for stress distribution near the crack tip in each layer of the plate are obtained; the limiting equilibrium of layered plate having a transverse crack is studied. The results presented can be applied to strength evaluation of layered plates within the framework of fracture mechanics. The paper presents the results obtained by the authors recently and proposes some generalisation.
Analiza stanu naprężeń w płytach warstwowych ze szczelinami W pracy przeprowadza się analizę stanu naprężeń w płytach warstwowych ze szczelinami poddanych dwuosiowemu rozciąganiu lub zginaniu stosując pewną metodę uśredniającą. Wykazuje się, że przy rozciąganiu można oprzeć się na klasycznej teorii płyt warstwowych, zaś w przypadku zginania zginania konieczne jest stosowanie teorii Timoshenki. Wyprowadzono asymptotyczne wzory rozkładu naprężeń w pobliżu wierzchołka szczeliny w każdej warstwie płyty. Wzory te zależą od modułów efektywnych płyty warstwowej oraz od uśrednionego współczynnika intensywności naprężeń. Przedstawiony model zawiera energetyczny test powiększania się szczeliny przy dwuosiowym rozciąganiu płyty.
Źródło:
Journal of Theoretical and Applied Mechanics; 2000, 38, 4; 819-832
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The failure analysis of the drilling rig hoisting steel wire rope
Autorzy:
Peterka, Pavel
Krešák, Jozef
Vojtko, Marek
Halek, Branislav
Heinz, David
Powiązania:
https://bibliotekanauki.pl/articles/1841928.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
wire rope
fatigue failure
cracks
NDT
Opis:
Drilling rigs belong to the lowest-safety level of hoisting rope systems. The valid regulation for drilling permits the usage of steel ropes on condition that their permanent safety does not decrease under the value 2.5. Considerable dynamic and cyclic stresses, abrasion and corrosive environment generated during the operation cause rapid fatigue and rope damage. The stress of the rope in operation leads to the specific precautions ensuring the safety rope work. The specific precautions include monitoring of the rope tractive work measured in tonne-kilometres (ton-kilometres services). The working part of the hoisting ropes of the drilling rigs - after the stated number of tonne kilometres was worked off - is slipped and a regular non-destructive rope test (NDT) is recommended. Rope under sizing, failing in rope slipping program and non- implementation of NDT controls led to the situations endangering the drilling crew safety. After the critical situations the operator decided to perform the analysis of the condition of all ropes.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 4; 667-675
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mitral regurgitation and its modern treatments
Autorzy:
Pręgowski, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/1916655.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mitral regurgitation
heart failure
percutaneus intervention
Opis:
Mitral regurgitation is the second most common valvular disease. The etiology is either primary or functional-secondary  to the left ventricle dysfunction in the course of coronary artery disease, arterial hypertension and diabetes. Along with the population aging and increasing number of comorbidities the number of patients with mitral regurgitation soars. In patients with heart failure the mitral regurgitation significantly decreases the quality of life and worsens the survival prognosis. Surgical correction is the treatment of choice in patients with mitral regurgitation. However, up to 50% of potential candidates are denied surgery for its prohibitive risk. The minimally invasive, percutaneus procedures are potential solution for those subjects. Currently the „edge to edge” technique with use of the MitraClip system is most commonly performed. This procedure is less efficient in MR reduction than open heart surgery. However, the number of periprocedural complications is smaller. It has been shown the MR correction with the MitraClip device improves the duration and quality of life. There are several ongoing preclinical studies on the percutaneusly implanted mitral valve prosthesis. First in men procedures have been performed. However the mitral valve anatomy is much more complex as compared to aortic. Therefore the breakthrough comparable to TAVI procedure will not occur in the very close future.
Źródło:
Nauka; 2020, 3
1231-8515
Pojawia się w:
Nauka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability Design of Complex Systems by Minimizing the Lifetime Variance
Autorzy:
Łobos, E.
Momot, M.
Powiązania:
https://bibliotekanauki.pl/articles/908509.pdf
Data publikacji:
2002
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
matematyka
reliability
constant failure rate
redundancy
Opis:
The problem considered in this paper is the minimization of the lifetime variance of a complex system subject to its expected life and economic constraints. The example of a bridge network, in which all elements have constant failure rates, illustrates the problem. A numerical algorithm for solving this optimization problem by using exact formulae for system lifetime moments is included. Using this algorithm, we can obtain results better than the solutions known from earlier papers.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2002, 12, 4; 553-557
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Czynniki wpływające na niezawodność pracy sieci dystrybucyjnych
Factors influencing the reliability of distribution grids
Autorzy:
Wnukowska, Bogumiła
Powiązania:
https://bibliotekanauki.pl/articles/34105735.pdf
Data publikacji:
2023-09-30
Wydawca:
Collegium Witelona Uczelnia Państwowa
Tematy:
niezawodność
energia
awaria
reliability
energy
failure
Opis:
Jednym z najważniejszych zagadnień związanych z niezawodnością zasilania odbiorców jest sprawne funkcjonowanie sieci dystrybucyjnej. W pracy omówiono najważniejsze elementy elektroenergetycznej sieci dystrybucyjnej średniego napięcia. Przedstawiono przypadki awarii oraz ich wpływ na odbiorców energii elektrycznej oraz powstałe skutki. Praca zawiera analizę przyczyn powodujących awarie sieci dystrybucyjnej, dokonaną na podstawie dostępnych materiałów źródłowych oraz oddziaływanie awarii na odbiorców energii elektrycznej, a także na bezpieczeństwo energetyczne kraju.
One of the main problems connected with energy supply reliability is the efficient functioning of distribution grids. This paper discusses major elements of a medium voltage electric grid. It also presents cases of its failure as well as their outcomes and influence on energy consumers. This paper contains an analysis of the causes of distribution grid failure based on the available source materials and its consequences consumers as well as energy security of countries.
Źródło:
Zeszyty Naukowe Collegium Witelona; 2023, 3, 48; 11-26
2956-302X
2956-3208
Pojawia się w:
Zeszyty Naukowe Collegium Witelona
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the gas network failure and failure prediction using the Monte Carlo simulation method
Analiza awaryjności sieci gazowych oraz prognozowanie awarii z zastosowaniem symulacyjnej metody Monte Carlo
Autorzy:
Tchórzewska-Cieślak, B.
Pietrucha-Urbanik, K.
Urbanik, M.
Powiązania:
https://bibliotekanauki.pl/articles/301501.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
failure of gas network
Monte Carlo method
analysis of the failure structure
failure prediction
awaryjność sieci gazowej
metoda Monte Carlo
analiza struktury awaryjności
prognozowanie awaryjności
Opis:
The scope of the article includes the analysis of the gas network failure based on a material obtained from field tests covering the years 2004-2014, conducted on the gas network of 120 thousand city, allowing to specify the failure rate of the gas network with division into material, pressure and pipelines diameter and indicate the main causes of failure on gas networks. On the base of the results of this analysis the Monte Carlo method to predict failures in gas pipe network has been presented.
Artykuł swoim zakresem obejmuje analizę awaryjności sieci gazowej na podstawie uzyskanego materiału z badań eksploatacyjnych obejmujących lata 2004-2014 prowadzonych na terenie Zakładu Gazowniczego w 120 tys. mieście, co pozwoliło na podanie intensywności uszkodzeń sieci gazowych z podziałem na materiał, ciśnienie i średnice rurociągów oraz podanie głównych przyczyn powstawania awarii na sieciach gazowych. Na podstawie wyników analizy zaprezentowano zastosowanie metody Monte Carlo do prognozowania awarii sieci gazowych.
Źródło:
Eksploatacja i Niezawodność; 2016, 18, 2; 254-259
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implementation of RCM theory in air operations
Autorzy:
Bugaj, M.
Powiązania:
https://bibliotekanauki.pl/articles/393850.pdf
Data publikacji:
2011
Wydawca:
Polskie Stowarzyszenie Telematyki Transportu
Tematy:
konserwacja
awarie
niezawodność
maintenance
reliability
failure
Opis:
Reliability-Centred Maintenance (RCM) implementation provides measures that signify progress towards implementing an RCM based maintenance program. Using numbers identified during the Analysis Phase as a basis, the metrics concentrate on the number and percentage of each category (new task, modified task, cancellation of specified old program tasks, design modifications, operational procedure changes, etc., that have actually been implemented. Implementation will (or should) usually begin during the Analysis Phase of an RCM project, and may provide information for improvement of the analysis. Implementation involves many activities, such as: Identification of resources (money, time, manpower), Coordination with governing authorities or other parties affected, Procedure writing, walk down and approval, Procurement of special tools, parts and consumables needed to carry out the procedures mandated under the new program, Training or at least orientation on the new procedures for those who are to perform them, Planning and scheduling of new RCM based procedures, Actual execution the first time on the asset that was subject of the RCM Project.
Źródło:
Archives of Transport System Telematics; 2011, 4, 1; 13-17
1899-8208
Pojawia się w:
Archives of Transport System Telematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The impact of renal function on clinical and biochemical characteristics in advanced heart failure patients
Autorzy:
Bohdan, Michał
Frankiewicz, Anna
Gruchała, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/895727.pdf
Data publikacji:
2019-02-05
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
heart failure
kidney disease
exercise capacity
Opis:
Background: Coexistence of heart failure with reduced ejection fraction (HFrEF) and chronic kidney disease is associated with poor prognosis. We assessed the effect of renal function on exercise capacity and clinical parameters of patients with HF. Material and methods: Forty five patients aged 58.2 ± 10.6 years with stable severe HFrEF were recruited. Patients were divided into 3 groups: group 1 - eGFR: 30-59 ml/min/1.73 m2; group 2 - eGFR: 60-89 ml/min/1.73 m2 and group 3 - eGFR: ≥90 ml/min/1.73 m2. Biochemical analysis, echocardiography, 6-minute walking test and cardiopulmonary stress testing were performed. Results: Patients in group 1 were significantly older than patients in group 3 (60.4 ± 11.1 years vs. 49.25 ± 11.2 years, respectively, p<0.05). Patients in group 2 had significantly higher BMI in comparison to group 3 (29.8 ± 4.4 vs. 25.1 ± 4.2; p<0.05). Interestingly, patients in group 1 had significantly lower peak oxygen uptake (10.2 ± 3.1 ml/kg/min vs. 16.1 ± 3.5 ml/kg/min, p<0.05) and oxygen uptake at anaerobic treshold (7.9 ± 2.4 ml/kg/min vs. 10.7 ± 1.9 ml/kg/min, p<0.05). Conclusions: Diminished renal function in patients with stable, advanced HFrEF may be associated with significantly worse peak VO2 and VO2 in AT.
Źródło:
European Journal of Translational and Clinical Medicine; 2018, 1, 2; 17-22
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Risk factors for poor prognosis in heart failure with particular attention to the elderly population
Autorzy:
Dobrowolska, Małgorzata
Miękus, Paweł
Świątczak, Michał
Raczak, Grzegorz
Daniłowicz-Szymanowicz, Ludmiła
Powiązania:
https://bibliotekanauki.pl/articles/1891021.pdf
Data publikacji:
2021-12-02
Wydawca:
Gdański Uniwersytet Medyczny
Tematy:
heart failure
risk factors
prognosis
elderly
Opis:
Background: Heart failure (HF) is a leading cause of poor outcome. Age is considered one of the most critical risk factors for both the incidence and prognosis of HF. Therefore we aimed to assess the predictors of poor prognosis in HF patients with particular attention to the elderly population. Material and methods: We retrospectively enrolled patients hospitalized due to HF exacerbation during 2016-2017 (203 patients). The end-points were all-cause mortality and emergency rehospitalizations within a two-year follow-up period. A detailed analysis was performed in the subgroups of patients younger and older than 65 years old. Results: 121 (60%) patients experienced the end-points. Age, low systolic blood pressure, NYHA class IV, right ventricle HF symptoms, high C-reactive protein, troponin, NT-proBNP, hyponatremia, catecholamine therapy and mechanical ventilation during hospitalization independently predicted the end-points. The elderly were characterized by a higher incidence of concomitant diseases and HF with moderately reduced or preserved LVEF, worse laboratory parameters and pharmacological treatment, as well as worse prognosis. Conclusion: The prognosis of patients hospitalized due to HF, mainly the elderly, is poor. Simple clinical parameters could be useful in further decision-making regarding the intensification of their treatment.
Źródło:
European Journal of Translational and Clinical Medicine; 2021, 4, 2; 18-30
2657-3148
2657-3156
Pojawia się w:
European Journal of Translational and Clinical Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 936

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