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Search results for: curring characteristics
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Acid-aided epoxy-amine curing reaction as reflected in epoxy/Fe3O4 nanocomposites: Chemistry, mechanism, and fracture behavior
PublicationThis work seeks to answer the question whether or not the presence of acid functional groups accelerate epoxyamine curing reaction. Epoxy/Fe3O4 nanocomposite was considered as a case, where discussions are based on chemistry, mechanism behind curing reactions and fracture behavior influenced by acid assistance to crosslinking. Fe3O4 magnetic nanoparticles (MNPs) with nanosilica decorative layer (B-MNP) were synthesized and subsequently...
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Unconditionally blue: Curing epoxy with polyethylene glycol (PEG) surface-functionalized Zn Fe3-O4 magnetic nanoparticles
PublicationNanoparticles govern early (chemical-controlled) and late (diffusion-controlled) stages of epoxy crosslinking, respectively. Surface functionalization of nanoparticles with macromolecules was recognized as an effective route to compensate for inadequate diffusion-controlled crosslinking. However, the effect of bulk composition amended with cations having catalytic effect towards epoxy ring opening has remained hitherto undescribed....
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Urinary tract infection in children: Diagnosis, treatment, imaging – Comparison of current guidelines
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Diffuse axonal injury – an interdisciplinary problem. Current knowledge and two case reports
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Transcranial magnetic stimulation (TMS) in treatment of psychiatric disorders – review of current studies
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Needs assessment of people 75+ living in a nursing home or family home environment
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Study of Applying Naturally Occurring Mineral Materials for Silicone Pressure-Sensitive Adhesives
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Comparison Study on Sonodirect and Sonoalternate Current Electrocoagulation Process for Domestic Wastewater Treatment
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Experimental method to evaluate the load-carrying capacity of double corrugated sheet profiles
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The Research into the Effect of Conditions of Combined Electric Powered Diamond Processing on Cutting Power
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Scabies – still current medical and social problem. A retrospective analysis of 193 cases
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Needs assessment study of rare diseases education for nurses and nursing students in Poland
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Trans-Z-source-like inverter with built-in DC current blocking capacitors
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Determination of the chemical structure of potential organic impurities occurring in drug substance opipramol
PublicationThe tricyclic antipsychotic and antidepressant drug opipramol (opipramole) was examined with regard to the chemical structure of its organic impurities. Impurities were isolated from the technical product by chromatographic methods and their chemical structures were established by 1H NMR, MS and FTIR and further confirmed by comparison with commercially available products or with products obtained by independent synthesis, and...
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Assessment of hardened layer thickness for 40HNMA steel using eddy current method
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Current epidemiological situation in the context of inclusion body hepatitis in poultry flocks in Poland
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Experimental studies on specific cutting resistance while cuttingwith narrow-kerf saws
PublicationBadania eksperymentalne właściwego oporu skrawania zostały wymuszone poprzez pojawienie się nowych technologii przecinania za pomocą cienkich pił. W przeprowadzonym eksperymencie wartościami wejściowymi były: rozwarcie całkowite ostrzy (rzaz), posuw na ostrze oraz grubość brzeszczotu piły. W ten sposób, oprócz zmian całkowitego przekroju warstwy skrawanej uwzględniano również wpływ warunków tarcia pomiędzy brzeszczotem piły, ścianami...
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Open-transistor fault diagnostics in voltage-source inverters by analyzing the load current
PublicationA novel method is presented for the detection andisolation of open-transistor faults in voltage-source invertersfeeding low-power AC motors. The method is based onmonitoring two diagnostic signals, one indicating sustained nearzerovalues of output current and thus permitting fault detection,the other permitting the isolation of the particular transistorwhich went faulty. The latter signal is the ratio of the averagephase current...
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Influence of circuit breaker operation upon transformeros residual flux and inrush current
PublicationPrzedstawiono model i wyniki obliczeń prądu i strumienia magnetycznego w układzie zawierającym transformator trójfazowy i wyłącznik. Opracowano obwodowy model łącznika z łukiem elektrycznym. Model łuku zbudowano w oparciu o jego statyczną charakterystykę prądowo-napięciową z uwzględnieniem uproszczonej charakterystyki dynamicznej. Przeprowadzone symulacje wykazały, że wartość maksymalna prądu włączania transformatora zależy zarówno...
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Turning maneuver as a potential cause of the next stability failure mode for a ship in operation
PublicationThe only formal stability-related requirement referring to a turning maneuver of a ship results from the IS Codeand its application is limited to passenger ships only. The goal of the adopted criterion is to prevent an excessiveangle of heel in turn. Likewise, the remaining prescriptive criteria, this one is simply based on the concept ofa threshold that must not be exceeded. In this case, the angle of heel...
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Current Trends in the Development of Microwave Reactors for the Synthesis of Nanomaterials in Laboratories and Industries: A Review
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LOCAL E-MARKETING AND PHARAMACY SELECTION PROCESS AMONG CURRENT AND PROSPECTIVE CONSUMERS
PublicationWORK OBJECTIVES: To examine whether and to what extent a company's presence in Google Search mobile results, and Google Maps service search results, affects pharmacies' acquisition of new consumers RESEARCH QUESTIONS: Does the presence of pharmacies in Google MyBusiness increase the number of their customers ? Is the increase in the...
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Ageism and loneliness in the subjective perceptions of elderly people from nursing homes and households
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Adsorption performance of graphitic carbon nitride-based materials: Current state of the art
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On the light intensity dependence of short-circuit current of bilayer organic photovoltaic cells
PublicationPraca przedstawia model zależności prądu zwarcia w organicznych dwuwarstwowych układach fotowoltaicznych od natężenia światła. Model jest oparty na założeniu jednorodnego pola elektrycznego w obu warstwach organicznych. Uwzględniona jest bimolekularna i monomolekularna rekombinacja nośników ładunku przy heterozłączu. Przedstawione zostało porównanie obliczeń teoretycznych i wyników doświadczalnych dla układów z barwnikiem perylenowym...
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[Chapter III] Influence of chip transport method on effects of cutting with circular saw
PublicationW pracy przedstawiono analizę transportu wiórów ze strefy skrawania na zewnątrz materiału obrabianego w procesie przecinania drewna piłami tarczowymi. Przedstawiono również przykłady zużycia pił tarczowych spowodowanych niewłaściwym transportem wiórów.
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Intelligent Optimization of Hard-Turning Parameters Using Evolutionary Algorithms for Smart Manufacturing
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Study on physical and technological effects of precise turning with self-propelled rotary tool
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Surface quality and topographic inspection of variable compliance part after precise turning
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Testing sensitivity of A-type residual current devices to earth fault currents with harmonics
PublicationIn many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in...
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Empirical verification in industrial conditions of fracture mechanics models of cutting power prediction
PublicationA comparison of experimental results obtained in the industrial conditions at a sawmill located in the Baltic Natural Forest Region (PL) and theoretical cutting power consumption forecasted with the models which include work of separation (fracture toughness) in addition to plasticity and friction has been described. In computations of cutting power consumption during rip sawing of Scots pine wood (Pinus sylvestris L.) values of...
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Phytoremediation—From Environment Cleaning to Energy Generation—Current Status and Future Perspectives
Publication:Phytoremediationis a technology based on the use of green plants to remove, relocate, deactivate, or destroy harmful environmental pollutants such as heavy metals, radionuclides, hydrocarbons, and pharmaceuticals. Under the general term of phytoremediation, several processes with distinctively different mechanisms of action are hidden. In this paper, the most popular modes of phytoremediation are described and discussed. A broad...
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Overview of current communication systems for security forces. Features, limitations and potential solutions
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Motor Cable Effect on the Converter Fed AC Motor Common Mode Current
PublicationAnaliza zaburzeń elektromagnetycznych przewodzonych w przekształtnikowych układach napędowych wymaga uwzględniania pojemności pasożytniczych występujących w przekształtniku, uzwojeniach silnika oraz kablu zasilającym silnik. Dynamiczne zmiany napięć na uzwojeniach silników zasilanych z przekształtników częstotliwości PWM oraz związane bezpośrednio z nimi składowe wspólne prądów zaburzeń przewodzonych są istotnie związane z zjawiskami...
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A new approach to determination of the two-mass model parameters of railway current collector
PublicationThe paper presents two mathematical models of railway current collectors both with two degrees of freedom. The first one, hereinafter Pantograph Articulated Model (PAM), has one degree of freedom in rotational motion and the second degree of freedom in translational motion. The second model, called henceforth as Pantograph Reference Model (PRM), has both degrees of freedom in translational motion. Differential equations of the...
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Supply current signal and artificial neural networks in the induction motor bearings diagnostics
PublicationThis paper contains research results of the diagnostics of induction motor bearings based on measurement of the supply current with usage of artificial neural networks. Bearing failure amount is greater than 40% of all engine failures, which makes their damage-free operation crucial. Tests were performed on motors with intentionally made bearings defects. Chapter 2 introduces the concept of artificial neural networks. It presents...
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Wear estimation of current collector contact strips by analysis of a 3D scanning results
PublicationThe technical condition of current collector contact strips is very important when operational reliability of railway transportation is considered. The authors proposed a novel measurement system based on a 3D camera to register the shape and dimensions of the current collector contact strips surface. The system was installed above the railway track for tests in target ambient. During the trial operation a few dozen of contact...
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Influence of electric, magnetic and electromagnetic fields on the circadian system – current stage of knowledge
PublicationOne of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues and...
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Magnetic Field Generated by Short Circuit Current in the 110 kV Power System
PublicationElectric fields within tissues induced by magnetic fields including transients or short-term peaks should not be time averaged and be regarded as instantaneous values as established in the ICNIRP (International Commission on Non - Ionizing Radiation Protection) guidelines. Measurements of power lines magnetic fields with regard to human beings exposure are carried out typically with maximum current load at current balance condition...
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Fault loop impedance measurement in low voltage network with residual current devices
PublicationW sieciach i instalacjach niskiego napięcia z wyłącznikami różnicowoprądowymi pomiar impedancji pętli zwarciowej jest kłopotliwy. Prąd pomiarowy powoduje ich zbędne zadziałanie, co uniemożliwia prawidłowe wykonanie pomiaru. W artykule omówiono przyczyny zbędnego zadziałania wyłączników różnicowoprądowych podczas pomiaru impedancji pętli zwarciowej oraz warunki, w jakich ten pomiar można wykonać poprawnie.
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Numerical Analysis of Magnetic Core Properties Influence on Residual Current Device Behaviour
PublicationW artykule przedstawiono analizę wpływu kształtu prądu w uzwojeniu pierwotnym transformatora prądowego na pracę przekładnika różnicowo-prądowego. Przeprowadzono obliczenia symulacyjne dla wymuszenia o kształcie sinusoidy i sinusoidy wyprostowanej dla częstotliwości 50 Hz. Wzięto pod uwagę dwa typy charakterystyki magnesowania transformatora: dla materiału magnetycznie miękkiego i materiału o prostokątnej pętli histerezy. Analiza...
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Open-transistor fault diagnostics in voltage-source inverters by analyzing the load current
PublicationPrzedstawiono nową metodę detekcji i lokalizacji uszkodzeń polegających na braku przewodzenia tranzystorów w falownikach napięcia zasilających silniki indukcyjne. Metoda jest rozszerzeniem, opracowanej wcześniej, metody wykorzystującej znormalizowane składowe stałe prądów obciążenia. Znormalizowane wartości średnie prądów powiązano z dodatkowymi wskaźnikami diagnostycznymi, które zawierają informacje o czasie trwania nieprzewodzenia...
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Corrosivity of environment and the current state of the steel elements at the former Auschwitz concentration camp
PublicationThe objective of this study was to assess corrosivity of the atmospheric environment in the former Auschwitz I and Auschwitz II-Birkenau concentration and extermination camp, and to identify the protective properties of existing corrosion products in order to estimate the actual corrosion rate of original steel elements located there. The current atmospheric corrosivity of the former Auschwitz camp, specified during one year of exposure...
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Programmable Input Mode Instrumentation Amplifier Using Multiple Output Current Conveyors
PublicationIn this paper a programmable input mode instrumentation amplifier (IA) utilising second generation, multiple output current conveyors and transmission gates is presented. Its main advantage is the ability to choose a voltage or current mode of inputs by setting the voltage of two configuration nodes. The presented IA is prepared as an integrated circuit block to be used alone or as a sub-block in a microcontroller or in a field...
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Modular high precision high current source for special applications — Simulation and verification
PublicationThis paper presents selected issues concerning realization of high precision high current source for special applications, where high demands of output parameters of such device are required. A new 80 kW prototype of modular high precision high current source is presented, where output current accuracy reaches 5x10-5. This paper presents also results of operation of the simulation model and of the prototype converter. In order...
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Load carrying capacity of the eccentric joint in the truss made of open cross-sections
PublicationThe influence of eccentricity at intersections of truss members on the load carrying capacity of the truss joint is presented in the paper. The research truss elements were designed as cold-formed open cross section. Analytical calculations, numerical analysis and experimental research were conducted to reveal how the eccentricity affects the effort of material in the joint area. The results of analysis and investigations are compared...
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Current based Normalized Triple Covariance as a bearings diagnostic feature in induction motor
PublicationDiagnosis of induction motors, conducted remotely by measuring and analyzing the supply current is attractive with the lack of access to the engine. So far there is no solution, based on analysis of current, the credibility of which allow use in industry. Statistics of IM bearing failures of induction motors indicate, that they constitute more than 40% of IM damage, therefore bearing diagnosis is so important. The article provides...
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Parametrical Method for Determining Optimal Ship Carrying Capacity and Performance of Handling Equipment
PublicationThe paper presents a method of evaluating the optimal value of the cargo ships deadweight and the coupled optimal value of cargo handling capacity. The method may be useful at the stage of establishing the main owners requirements concerning the ship design parameters as well as for choosing a proper second hand ship for a given transportation task. The deadweight and the capacity are determined on the basis of a selected economic...
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Improving sensitivity of residual current transformers to high frequency earth fault currents
PublicationFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed...
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Improving Control Dynamics of PMSM Drive by Estimating Zero-Delay Current Value
PublicationDynamic performance of current control loop still remains crucial for position-, speed-, and torque-controlled drives. In the study, a current loop solution has been designed for field oriented control of permanent magnet synchronous motors (PMSM). It enhances typical PI controller with an estimator of zero-delay current (ZDC) value. The ZDC estimation allows for selecting substantially higher controller gain. It reduces control...