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Experimental and Computational Analysis of the Ship Propeller in Open Water Conditions for Inclined Flow
PublikacjaThe paper presents the results of computational analyses simulating the open water tests of ship propeller in inclined flow. The results of computations are compared with the results of corresponding experimental analyses carried out in the towing tank of Ship Design and Research Centre (CTO S.A.). The object of the research was the model propeller identified as CP469. The aim of the study was to validate the results of numerical...
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Minimization of a ship's magnetic signature under external field conditions using a multi-dipole model
PublikacjaThe paper addresses the innovative issue of minimizing the ship's magnetic signature under any external field conditions, i.e., for arbitrary values of ambient field modulus and magnetic inclination. Varying values of the external field, depending on the current geographical location, affect only the induced part of ship's magnetization. A practical problem in minimizing the ship signature is separating permanent magnetization...
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Structural changes of bacterial cellulose due to incubation in conditions simulating human plasma in the presence of selected pathogens
PublikacjaBacterial nanocellulose (BNC) is a natural biomaterial with a wide range of medical applications. However, it cannot be used as a biological implant of the circulatory system without checking whether it is biodegradable under human plasma conditions. This work aimed to investigate the BNC biodegradation by selected pathogens under conditions simulating human plasma. The BNC was incubated in simulated biological fluids with or...
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Numerical and experimental study on effect of boundary conditions during testing of stiffened plates subjected to compressive loads
PublikacjaThis study analyses the effect of boundary conditions during testing on the structural behaviour stiffened plates with different thicknesses subjected to compressive loads. The goal of the compressive tests is to analyse the ultimate strength of a stiffened plate. During the test, relevant physical quantities are measured and investigated. The supporting structure's behaviour is investigated by analysing the force-displacements...
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Effect of crystallization process at cryogenic conditions on the functional properties of the SUPERSTON alloy used in production the ship's propellers
PublikacjaThe purpose of this paper is to show results of laser treatment at cryogenic conditions of the SUPERSTON alloy used for ship's propellers. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. During the laser remelting at cryogenic conditions the microstructure changes significantly. This is related to synergistic effects of the solidification rate, phase transformations...
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INFLUENCE OF TEST CONDITIONS ON TYRE/ROAD NOISE MEASURED BY THE DRUM METHOD
PublikacjaTyre/road noise is one of the most important environmental problems related to road traffic. Nowadays a few standard procedures of tyre/road noise measurements are in use. Unfortunately, measurement conditions specified within relevant standards are very different. For example, procedure described in ISO 11819-2 used for pavement investigations requires tyre load of 3200 N and capped inflation pressure of 200 kPa. At the same time...
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Experimental study on steel columns subjected to impact load under earthquake conditions
PublikacjaEarthquakes affecting urbanized regions cause exceptional loads to load bearing structural elements such as columns. Such a boost in the load conditions can lead to severe damages which, in a worst case scenario, can lead to a total collapse of a building. This boost is caused by the horizontal ground movement generating a rise in the internal forces due to considerable large displacement between the top and bottom support of columns....
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How digital technology affects working conditions in globally fragmented production chains: Evidence from Europe
PublikacjaThis paper uses a sample of over 9 million workers from 22 European countries to study the intertwined relationship between digital technology, cross-border production links and working conditions. We compare the social consequences of technological change exhibited by three types of innovation: computerisation (software), automation (robots) and artificial intelligence (AI). To fully quantify work-related wellbeing, we propose...
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Exact resultant equilibrium conditions for intersecting shells
PublikacjaWyprowadzono ścisłe, globalne i lokalne warunki równowagi dla dwóch przecinających się powłok. Wspólna powierzchnia podstawowa powłoki składa się z czterech regularnych powierzchni materialnych, sztywno połączonych wzdłuż powierzchniowej krzywej osobliwej modelującej połączenie. Localne warunki równowagi otrzymano poprzez ścisłe całkowanie po grubości powłoki globalnych warunków równowagi mechaniki ośrodka ciągłego.
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Reception of GNSS Signals Under Jamming Conditions
PublikacjaThe article focuses on performance of Global Navigation Satellite System receivers in environment where intentional interference is present. First part is a general description of GNSS systems. Secondly, types of positioning service disturbances are specified. In the third part authors present a scheme of measurement stand which is used to evaluate the influence of interference on reception of navigation signals. Next, research...
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Influence of traffic conditions on the operating fuel consumption
PublikacjaPrzedstawiona w pracy metoda umożliwia ocenę warunków eksploatacji pojazdu. Warunki te mogą wynikać zarówno z lokalnej specyfiki ruchu pojazdów jak również ze sposobu prowadzenia auta przez kierowcę. W pracy zamieszczono przykłady oceny zarejestrowanych w normalnej eksploatacji warunków ruchu pojazdu i ich wpływu na przebiegowe zużycie paliwa.
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A model of risk for assessment of ships in damaged conditions
PublikacjaW pracy omówiono problemy związane z modelowaniem zagrożeń, konsekwencji i ryzyka, w metodzie oceny bezpieczeństwa statków w stanie uszkodzonym. W celu dokonania oceny bezpieczeństwa statku, w metodzie zastosowano podejścia oparte na ocenie zachowania się statku i ocenie ryzyka. Podejście oparte na ocenie zachowania się statku związane jest z oceną charakterystyk hydromechanicznych statku w stanie uszkodzonych w warunkach zbliżonych...
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Control conditions for geocomputing within general hypoplasticity
PublikacjaPrzedstawiono w artykule analizę oryginalności i stabilności problemu warunków brzegowych (BVP). Zaprezentowano niektóre warunki numeryczne, dzięki którym można uzyskać oryginalne i stabilne rozwiązania w zakresie hypoplastyczności. Przeanalizowano wiele teoretycznych aspektów, które pojawiają się wskutek zmiany typu równań różniczkowych. Wyprowadzono kryteria dla przypadku liniowego, dobrze postawionego problemu i dla stabilności...
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Protochlorophyllide in model systems — An approach to in vivo conditions
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Existence of solutions of differential equations with boundary conditions
PublikacjaPraca dotyczy równań różniczkowych z liniowym warunkiem brzegowym zależnym od parametru. Podane zostały warunki dostateczne na istnienie rozwiązania powyższego zagadnienia. Przy dowodzie i konstrukcji iteracji monotonicznych zastosowano metodę górnych i dolnych rozwiązań. O prawej stronie zagadnienia zakładano jednostronny warunek Lipschitza.
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Influence of the annealing conditions on the resistivity of Nd2CuO4 singlecrystals
PublikacjaW pracy wyznaczono temperaturową zależność oporności w płaszczyźnie ab dla dwóch grup kryształów Nd2CuO4 w zakresie 50-300 K.
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Advanced differential equations with nonlinear boundary conditions.
PublikacjaBadano problemy istnienia rozwiązań dla równań różniczkowych z nielinowymi warunkami brzegowymi. Podano też warunki dostateczne na istnienie rozwiązań ekstremalnych. Przedmiotem badań były również nierówności różniczkowe z wyprzedzonym argumentem.
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On delay differential equations with nonlinear boundary conditions
PublikacjaStosując metodę iteracji monotonicznych podano warunki dostateczne na istnienie kwazirozwiązań lub ekstremalnych rozwiązań rozpatrywanego zagadnienia. Problem jednoznaczności rozwiązania był również przedmiotem badań. Zajmowano się również nierównościami różniczkowymi z opóżnionymi argumentami.
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Ordinar differential equations with nonlinear boundary conditions
PublikacjaPraca dotyczy zwyczajnych równań różniczkowych z nieliniowymi warunkami brzegowymi. Sformułowano warunki dostateczne na istnienie rozwiązania (jedynego lub ekstremalnych) zakładając pewną regularność na prawe strony równania i warunek brzegowy. Warunki brzegowe typu okresowego lub antyokresowego są szczególnymi przypadkami ogólnego warunku dyskutowanego w tej pracy.
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Effects of stents under asymmetric inflow conditions
PublikacjaW publikacji rozważano komputerowe modele stentów przy niesymetrycznych warunkach napływu i ich wpływ na naprężenia styczne na ściankach. Umożliwia to znajdowanie kształtów stentów, które są mniej wrażliwe na brak symetrii napływu. Zmiany kształtów arterii można wiązać ze zmianami charakterystyki przepływów takimi jak m.in. naprężenia styczne na ściankach, które zwiększają ryzyko restenozy. Posłużono się również pojęciem dyssypacji...
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Complexity of weak acceptonic conditions in tree automata
PublikacjaRozważano złożoność problemu pustości dla automatów na drzewach ze słabymi warunkami akceptowalności. Rozważano także translacje pomiędzy słabymi i silnymi warunkami akceptowalności.
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INFLUENCE OF MEASURING CONDITIONS ON TYRE/ROAD NOISE
PublikacjaA decisive factor for the development of tyres and road surfaces is the ability to conduct representative and reproducible measurements of selected characteristics related to the interaction of tyres and road surfaces. In terms of tyre/road noise measurements in Europe two methods described in ISO/FDIS 11819-2 and ECE Regulation No.117 are used. The latter is compulsory for assigning the tyre noise labels. The methodologies differ...
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Conditions and capacity for implementing Poland’s vision zero
PublikacjaSince 1991 Poland has been systematically reducing its traffic hazard. Despite considerable progress Poland is still among the most dangerous countries in the European Union. The key types of actions that help to reduce fatalities include enhancement of pedestrian safety, reducing the number of speeding drivers and eliminating or reducing hazard on the road. The paper presents a brief diagnosis of the state of road safety in Poland...
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Assessment of Road Restraint Systems in Polish Conditions
PublikacjaKey to understanding the needs and tools of road infrastructure management is identifying the hazards and their sources involved in having no or faulty road restraint systems. Clarity is also needed on why the systems are wrongly designed, constructed, built and operated. To ensure that the problem is adequately understood, research and site observations were conducted and...
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Improving the quality of speech in the conditions of noise and interference
PublikacjaThe aim of the work is to present a method of intelligent modification of the speech signal with speech features expressed in noise, based on the Lombard effect. The recordings utilized sets of words and sentences as well as disturbing signals, i.e., pink noise and the so-called babble speech. Noise signal, calibrated to various levels at the speaker's ears, was played over two loudspeakers located 2 m away from the speaker. In...
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CONDITIONS OF THE GREEN TRANSFORMATION. THE CASE OF THE EUROPEAN UNION
PublikacjaThe main purpose of the paper is to identify the factors that determine the course of green transformation and to assess the current stage and possible directions of change in subsequent years in EU countries. The literature lacks comprehensive studies that show the impact of diverse types of factors on the course of green transformation. For this purpose, two perspectives of the research – economic and environmental – are usually...
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Thermal performance of a prototype plate heat exchanger with minichannels under boiling conditions
PublikacjaTo solve the problem and to meet the requirements of customers in the field of high heat fluxes transfer in compact units, a new design of plate heat exchanger with minichannels (minichannels PHE) was proposed. The aim was to construct a compact heat exchanger of high effectiveness for the purpose of household cogeneration ORC system. In this paper the experimental analysis of an assembled prototype of such compact heat exchanger...
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Evaluation of fire hazard in electrical installations due to unfavorable ambient thermal conditions
PublikacjaEvaluation of fire hazard caused by electrical installations is a difficult and important topic, and it limits the possibility of loss of life or health of people, as well as the occurrence of significant property damage. In particular, this hazard was caused by power cables and especially photovoltaic (PV) installations. The authors proved that power cables directly exposed to strong solar radiation are likely to exceed maximum...
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Robustness of contact-less optical method, used for measuring contact wire position in changeable lighting conditions
PublikacjaThe article presents verification of robustness of contactless method based on 2D image camera, which is used to measure catenary contact wire position in changeable ambient lighting conditions. Robustness in changeable lighting conditions is ensured through the combination of advanced image processing for background information removal and the algorithm of error correction. This algorithm detects incorrect images and substitutes...
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Positive solutions to second-order differential equations with dependence on the first-order derivative and nonlocal boundary conditions
PublikacjaIn this paper, we consider the existence of positive solutions for second-order differential equations with deviating arguments and nonlocal boundary conditions. By the fixed point theorem due to Avery and Peterson, we provide sufficient conditions under which such boundary value problems have at least three positive solutions. We discuss our problem both for delayed and advanced arguments α and also in the case when α(t)=t, t∈[0,1]....
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Monotone iterative method to second order differential equations with deviating arguments involving Stieltjes integral boundary conditions
PublikacjaWe use a monotone iterative method for second order differential equations with deviating arguments and boundary conditions involving Stieltjes integrals. We establish sufficient conditions which guarantee that such problems have extremal solutions in the corresponding region bounded by lower and upper solutions. We also discuss the situation when problems have coupled quasi-solutions. We illustrate our results by three examples.
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The impact of footing conditions of a vertical-axis floating-roof tank on structural shell deformation
PublikacjaStructural shells of fuel tanks are often subjected to geometric imperfections which may lead to exceeding the ultimate and serviceability limit states. One of the means triggering shell deformation is non-uniform settlement caused by incoherent soil conditions. Analysis carried out in the work concerns of vertical-axis, floating-roof cylindrical shell which volume is 50.000 m3, founded on a complex multi-layered soil. The sensitivity...
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In vitro biodegradation of bacterial nanocellulose under conditions simulating human plasma in the presence of selected pathogenic microorganisms
PublikacjaThe Biodegradability of bacterial nanocellulose (BNC) was assessed based on a change in its properties under conditions simulating human plasma in the presence or absence of the pathogens Staphylococcus aureus, Candida albicans and Aspergillus fumigatus. It was shown that the dry mass of BNC did not change during 6 months of incubation, except for samples stored in the presence of moulds, where the dry mass reduced by 40 %. The...
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Investigating Fuel Injection Strategies to Enhance Ship Energy Efficiency in Wave Conditions
PublikacjaThe prediction of fuel consumption and resulting transportation costs is a crucial stage in ship design, particularly for conditions involving motion in waves. This study investigates the real-time fuel consumption of a container ship when sailing in waves. The overall ship performance is evaluated using a novel non-linear coupled hull-engine-propeller interaction model. A series of towing tank experiments for hull resistance in...
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Effect of Compounding Conditions on Static and Dynamic Mechanical Properties of High Density Polyethylene/Ground Tire Rubber Blends
PublikacjaSearching for new and cost-effective methods of waste rubber recycling is a subject of research in many scientific centers in the world. In this paper there are presented results of the research of the extrusion process of cheap and environmentally friendly thermoplastic compositions containing 50 % wt. of masses of ground tire rubber (GTR). The aim of this study was to determine the relationship between the mixing conditions and...
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Areas of Updraft Air Motion in an Idealised Weather Research and Forecasting Model Simulation of Atmospheric Boundary Layer Response to Different Floe Size Distributions
PublikacjaPresented dataset is part of a numerical modelling study focusing on the analysis of the influence of sea ice floe size distribution (FSD) on the horizontal and vertical structure of convection in the atmosphere. The total area and spatial arrangement of the up-drafts indicates that the FSD affects the total moisture content and the values of area averaged turbulent fluxes in the model domain. In fact, while convective updrafts...
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Analysis of cyclone separator solutions depending on spray ejector condenser conditions
PublikacjaThe core design strategy for minimizing CO2 emissions in gas power plant entails combining a spray ejector condenser (SEC) and separator to accomplish steam condensation and CO2 purification. This innovative process involves direct-contact condensation of steam with CO2, facilitated by interaction with a subcooled water spray, along with a cyclone separator mechanism intended for generating pure CO2. The investigation of the SEC...
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Analysis of cyclone separator solutions depending on SEC outlet conditions in nCO2PP
PublikacjaUtilization of spray ejector condenser in order to carry out direct-contact condensation of vapour with inert gas (CO2) on a spray of subcooled liquid integrated with separator (to make pure CO2) has been proposed for the task of condensation and CO2 separation in the negative CO2 emission gas power plant. Condensation and separation has a significant impact on the thermodynamic efficiency of the entire negative CO2 emission gas...
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Risk of Delays in Implementation of Building Investment in Urban Conditions in the Aspect of Historical Background of its Location
PublikacjaThe implementation of a construction investment in urban conditions is extremely complex, and at the same time exposed to a high risk of a specific character. In case of construction investment located in the historic part of the city, the possible accumulation of many unfavourable factors, which in course of its implementation, may constitute a serious source of delays and disruptions, should be taken into account at the preparation...
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STUDY OF ARRAY OF MEMS INERTIAL MEASUREMENT UNITS UNDER QUASI-STATIONARY AND DYNAMIC CONDITIONS
PublikacjaA measurement system includes all components in a chain of hardware and software that leads from a measured variable to processed data. In that context, the type and quality of the sensors or measuring devices are critical to any measurement system. MEMS/IMU sensors lag behind leading technologies in this respect, but the MEMS/IMU performance rapidly changes while is relatively inexpensive. For this reason, the paper proposes...
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Successive Iterative Method for Higher-Order Fractional Differential Equations Involving Stieltjes Integral Boundary Conditions
PublikacjaIn this paper, the existence of positive solutions to fractional differential equations with delayed arguments and Stieltjes integral boundary conditions is discussed. The convergence of successive iterative method of solving such problems is investigated. This allows us to improve some recent works. Some numerical examples illustrate the results.
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Ozone nanobubble technology as a novel AOPs for pollutants degradation under high salinity conditions
PublikacjaConventional water treatment systems frequently exhibit diminished efficiency at high salinity - a significant issue especially for real industrial effluents - mostly due to the creation of intricate structures between pollutants and salts. One of the primary obstacles associated with high salinity conditions is the generation of by-products that pose additional hurdles for treatment. In this work, we have investigated the novel...
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ANALYSIS OF WIND CONDITIONS AROUND A BUILDING DEVELOPMENT AS A PART OF ITS FORM DESIGNING PROCESS, A CASE STUDY
PublikacjaAerodynamic phenomena that occurs around building developments exert a significant impact on the quality of climate in cities. Environmental wind engineering is a dynamically developing field of knowledge that offers a chance to study and, in consequence, regulates the air flow around buildings and complexes of building developments. The following paper discusses the issue of wind conditions that may be experienced on pedestrian...
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Conditions for Multiple Acquisition of Echoes from Stationary Targets in Successive Transmissions of Active Sonars
PublikacjaIn echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple...
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A research on the optimal conditions for separation and identyfication of the components from the Droseraceae extracts by column liquid chromatography
PublikacjaThe isolation of the components with anticipated biological properties i.e. antimicrobial, fungicidal, antioxidant and perhaps anticancer activity is for many years a one of the biggest issues of modern separation science. Their obtaining based on the isolation of the components with the biological activity from in vitro cultured plants by extraction techniques is often more difficult than their production by the chemical synthesis.The...
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Logistical Aspects of Energy Conversion Efficiency in Marine Steam Power Plants in Off-Design Conditions
PublikacjaThe paper presents logistical aspects of energy conversion efficiency in off-design conditions. The main part of the article is based on results of thermodynamic calculation for large propulsion steam turbine under partial loads. Calculations are made on extended mathematical model of two proposed steam turbine thermodynamic cycles using Stodola’s cone law. The conclusion based on calculation re-sults contains importance of off-design...
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Weather Climate and Society
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MONTHLY WEATHER REVIEW
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Myrosinase activity in different plant samples; optimisation of measurement conditions for spectrophotometric and pH-stat methods
PublikacjaMyrosinase found in Brassicaceae plants, is the enzyme responsible for hydrolysis of glucosinolates. As a result a variety of biologically active metabolites are liberated, whose importance in crop protection and especially in cancer chemoprevention is rapidly gaining recognition. The growing practical application of glucosinolate degradation products requires that sensitive and reliable methods of myrosinase activity determination...
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Seven Different Lighting Conditions in Photogrammetric Studies of a 3D Urban Mock-Up
PublikacjaOne of the most important elements during photogrammetric studies is the appropriate lighting of the object or area under investigation. Nevertheless, the concept of “adequate lighting” is relative. Therefore, we have attempted, based on experimental proof of concept (technology readiness level—TRL3), to verify the impact of various types of lighting emitted by LED light sources for scene illumination and their direct influence...