Filters
total: 1375
filtered: 1074
-
Catalog
Chosen catalog filters
displaying 1000 best results Help
Search results for: WARS
-
Ocena wpływu zastosowania techniki strugowej na wydajność energetyczną modułów BIPV/T chłodzonych powietrzem
PublicationPraca ma charakter analizy numerycznej i dotyczy problematyki chłodzenia hybrydowych modułów fotowoltaicznych dedykowanych układom Building-Integrated Photovlotaic/Thermal (BIPV/T). Uwagę skupiono na powietrznym systemie chłodzenia dachówki fotowoltaicznej, rozważając technikę strugową, w której intensyfikację wymiany ciepła zapewniają strugi płynu uderzające w przegrodę wymiany ciepła. Przeprowadzono szereg symulacji numerycznych...
-
Cooperation of ORC installation with a gas boiler as a perspective co-generation system for households
PublicationThis paper reports tests of an innovative micro-CHP unit prototype, consisting of a traditional gas boiler and organic Rankine cycle (ORC), which incorporates original system components such as an axial vapour microturbine, evaporator and condenser. The system co-generates heat and electricity for a single household or a group of households. Electricity is only a by-product during production of heat. While testing the prototype,...
-
High-temperature heat pumps – new devices for heat recovery and production of technological steam
PublicationIn the paper, the original high temperature compressor based heat pump with a dry working fluid, i.e. the one in which the slope of saturated vapour line is positive, was presented. The objective of the paper is to investigate the possibility of preparation of technological steam with tempperature 120 C from the waste heat resource at temperature of 50 C. Single comppression cycles as well as cascade systems have been considered...
-
High-efficiency mini and micro heat exchangers for dispersed power generation
PublicationTaking into account the dispersed systems technologies and their development, the ORC systems seem to be promising technology amongst various micro-CHP domestic units (electrical power production below 10 kWe), however practical realization of the ORC cycle in a micro-scale is technically challenging. The system consists in devices such as the vapour generation unit (boiler), expansion device and heat exchangers. Each of them should...
-
High-temperature heat pumps – potential technology for heat recovery and production of process heat
PublicationIn the paper, the high temperature vapour compressor based heat pump with a selection of working fluids, both perspective and ecological ones, is considered. Such system is not yet commercially available on the market and in author’s opinion it has significant potential for various applications. In the presented analysis it was assumed that the heat source has a temperature of 50oC and the temperature lift is 60, 80 and 100K respectively....
-
Performance of the very high-temperature heat pump with low GWP working fluids
PublicationTraditional heat pumps are a very attractive pro-ecological solutions for a number of applications, including providing of heating or heat recovery from industrial processes. The application range of heat pumps could be greatly enlarged when the operating temperature would be increased to 130-150°C and/or the temperature lift can be increased to 50-100 K. In the paper, the very high temperature vapour-compressor based single stage...
-
Determination of dryout localization using a five-equation model of annular flow for boiling in minichannels
PublicationDetailed studies have suggested that the critical heat flux in the form of dryout in minichannels occurs when the combined effects of entrainment, deposition, and evaporation of the film make the film flow rate go gradually and smoothly to zero. Most approaches so far used the mass balance equation for the liquid film with appropriate formulations for the rate of deposition and entrainment respectively. It must be acknowledged...
-
HIGH TEMPERATURE HEAT PUMPS – PERSPECTIVE HEATING SYSTEMS?
PublicationIn the paper presented are authors own concepts of high temperature compressor heat pumps for the utilisation of medium and low temperature sources of heat. Working fluids for use in high temperature heat pumps are discussed, as well as the criteria for their selection. Analyses are presented for the production of in the upper steam source at 130 °C. One-stage systems and cascade systems were analyzed. An analysis of the coefficient...
-
Possibilities of heat transfer augmentation in heat exchangers with minichannels for marine applications
PublicationIn the paper, new trends in development of microchannel heat exchangers are presented. The exchangers developed in this way can be applied in marine applications. Main attention was focused on heat exchangers design with reduced size of passages namely based on microchannels. In our opinion future development of high power heat exchangers will be based on networks micro heat exchangers.
-
Assessment of the impact of jet impingement technique on the energy efficiency of air-cooled BIPV/T roof tile
PublicationThe paper concerns a numerical analysis of cooling of the hybrid photovoltaic (PV) modules dedicated to Building-Integrated Photovoltaic/Thermal (BIPV/T) systems. Attention was focused on the photovoltaic roof tiles, using a jet impingement technique, in which the intensification of heat transfer is ensured by streams of air hitting the heat exchange partition. A series of numerical simulations were carried out to assess an influence...
-
Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
PublicationAmong renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system...
-
Badania eksperymentalne wpływu obecności ścianki na ruch pęcherzyków w kanale pionowym.
PublicationW referacie zaprezentowano matematyczny model siły odpychającej działającej na kulę (model pęcherzyka) przepływającą wzdłuż ścianki pionowej. Stwierdzono, że siła ta ma charakter okresowy i zależy od liczby Reynoldsa oraz początkowej odległości pomiędzy kulą i ścianką. Dokonano porównania zarejestrowanej i obliczonej modelem trajektorii ruchu kuli uzyskując zadowalającą zgodność.
-
Influence of the wall on vertical bubble motion
PublicationZaprezentowano model siły odpychającej, działającej na kulę podczas przepływu wzdłuż ściany pionowej. Modelowana siła ma charakter okresowy. Uzyskano satysfakcjonującą zgodność pomiędzy zmierzoną i obliczoną wartością tej siły.
-
Modelling of vertical wall influence on the single bubble motion.
PublicationW referacie zaprezentowano rezultaty badań eksperymentalnych i modelowania matematycznego siły odpychającej, działającej na model pęcherzyka przepływający wzdłuż ściany pionowej. Zaobserwowano okresowy charakter tej siły oraz stwierdzono, że zależy ona od liczby Reynoldsa. Porównanie obliczonych i zmierzonych wartości siły wykazało satysfakcjonującą zgodność.
-
Decomposition of the wall force acting on the single bubble motion.
PublicationW referacie skupiono uwagę na rozkładzie siły hydrodynamicznej działającej na kulę (uproszczony model pęcherzyka) na kierunku prostopadłym do ścianki kanału. Pokazano stanowisko badawcze, omówiono procedurę pomiarową oraz zamiszczono przykładowe wyniki badań eksperymentalnych i modelowania matematycznego.
-
Modelling of Vertical Wall Influence on the Single Bubble Motion
PublicationW referacie pokazano rezultaty badań eksperymentalnych i modelowania matematycznego siły odpychającej, działającej na model pęcherzyka przepływający wzdłuż ściany pionowej. Zaobserwowano okresowy charakter siły oraz stwierdzono, że zależy ona od liczby Reynoldsa. Porównanie obliczonych i zmierzonych wartości siły wykazało satysfakcjonującą zgodność.
-
Modelling of bubble motion in vicinity of the wall
PublicationArtykuł skupiony jest na analizie odchylenia trajektorii cząstki stałej (modelowanej kulą) na skutek obecnosci ścianki kanału. Przebadano eksperymentalnie trzy wymiary cząstek. W wyniku redukcji danych doświadczalnych wyprowadzono korelację opisującą oddziaływanie ścianki na ruch pojedynczej cząstki.
-
Motion of a sphere in vicinity of the wall
PublicationW referacie rozważane jest odchylenie toru cząstki płynącej w pobliżu ścianki. Cząstka modelowana jest sztywną kulą podwieszoną na strunie. Systematyczne badania przeprowadzono dla trzech średnic kuli. Zaproponowano korelację opisującą oddziaływanie ścianki na ruch cząstki. Korelację wykorzystano do modelowania przepływu dwufazowego w wrstwie przyściennej
-
Motion of a sphere in vicinity of the wall
PublicationArtykuł skupiony jest na badanich odchylenia toru cząstki w sąsiedztwie ścianki. Cząstka modelowana jest nieodkształcalną kulą zawieszoną na strunie. Systematyczne badania z wykorzystaniem kul o trzech średnicach wykonano na specjalnie zbudowanym stanowisku eksperymentalnym. Zaproponowano autorską matematyczną korelację opisującą oddziaływanie ścianki na ruch cząstki - korelacja określa to oddziaływanie w funkcji początkowej odległości...
-
Numerical analysis of high temperature minichannels heat exchanger performance
PublicationNowadays, the most difficult technological challenge in energy sector is connected with the gas micro-CHP units, dedicated to the distributed power generation. They are expected to be of high efficiency and at the same time of compact in size. Regarding the first reason, significant increase in microturbine efficiency can only be achieved by increase in the engine operating temperature. Therefore, one of the critical elements in...
-
Thermal and Hydrodynamic Phenomena in the Stagnation Zone — Impact of the Inlet Turbulence Characteristics on the Numerical Analyses
PublicationOne of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied, for example, in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to the origin of this impact are still unanswered. In general, the wall-jet interaction and the near-wall turbulence are supposed to be its main reason, but their accurate numerical...
-
Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
PublicationConsidering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design...
-
A numerical analysis of the thermal effects in the jet impingement stagnation zone
PublicationMost of the flows occurring in the engineering systems are turbulent and their accurate numerical analysis is still challenging, especially when combined with the heat transfer. One of the methods of heat transfer enhancement is utilization of the turbulent impinging jets, which were recently applied also in the heat exchangers. Their positive impact on the heat transfer performance was proven, but many questions related to its...
-
Flow structure, heat transfer and scaling analysis in the case of thermo-magnetic convection in a differentially heated cylindrical enclosure
PublicationThe experimental, numerical and scaling analysis in the case of thermo-magnetic convection in a thermosyphon-like enclosure filled with a paramagnetic fluid is presented. Visualization of temperature field together with the numerical simulation gave an information about the flow structure, which indicated “finger-like” structures of hot and cold streams advecting each other. Their number depended on the Rayleigh number and also...
-
Magneto-thermal convection of low concentration nanofluids
PublicationThe main aim of this paper was to analyze possible utilization of the low concentration nanofluids and the magnetic field to enhance heat transfer. The studied fluids were based on water with an addition of copper particles (40-60 nm diameter). They belonged to the diamagnetic group of materials. As a first attempt to stated target the analysis of enclosure placed in the maximal value of square magnetic induction gradient was carried...
-
Optimum number of actuators to minimize the cross-sectional area of prestressable cable and truss structures
PublicationThis paper describes a new computational method for determining the optimum number of actuators to design the optimal and economic cross-sectional area of pin-jointed assemblies based on the conventional force method. The most active members are selected to be prestressed to redistribute stress in the whole structure, resulting in regulating the internal force of bars that face high stress. Reducing stress in critical members allows...
-
Eqiuitable coloring of corona products of cubic graphs is harder than ordinary coloring
PublicationA graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the number of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G. In this paper the problem of determinig the equitable coloring number for coronas of cubic graphs is studied. Although the problem of ordinary coloring of coronas...
-
Separation of CO2 from flue gas in air-sparged hydrocyclone (ash) reactor
PublicationPrzedmiotem badań była absorpcja dwutlenku węgla w wodnym roztworze wodorotlenku sodu, z fazy gazowej w skali laboratoryjnej i technologicznej z wykorzystaniem reaktora typu ash. Natężenie przepływu powietrza wynosiło 900 dm3/min a wodnego roztworu NaOH 15 dm3/min w skali technologicznej. Zbadano stężenie CO2, pH w fazie ciekłej, wpływ natężenia przepływu fazy gazowej i fazy ciekłej na efektywność absorpcji
-
Modeling BIM Objects From Point Clouds. Examples
PublicationThe article presents several ways to obtain BIM (Building Information Modeling) models from point clouds using standard commands in Revit 2018. In Revit geometric forms are possible to obtain in project, family or conceptual environments. Efficient modeling requires knowledge of methods of creating families and components in these environments and ways to combine them. Modeling methods with system and loadable families are presented,...
-
Application exaples of wide area monitoring for system operators within UCTE
PublicationW referacie przedstawiono przykładowe zastosowania pomiarów uzyskiwanych w systemie WAMS dla potrzeb systemu elektroenergetycznego.
-
Potential reduction of traffic noise by the means of increased fleet of electric vehicles using a combination of low-noise tyres and low-noise road surfaces
PublicationIn the future, the number of zero-emission vehicles like electric and plug-in hybrid vehicles (in electric mode) is expected to be a substantial part of the vehicle fleet. In Norway, such vehicles already account for approximately 20 % of all new cars sold. Since these vehicles emit negligible noise related to the power-train, the tyre/road noise is the dominating noise source. In the LEO project, tyres designed for such cars have...
-
Social learning in cluster initiatives
PublicationPurpose – The purpose of the paper is to portray social learning in cluster initiatives (CIs), namely: 1) to explore, with the lens of the communities of practice (CoPs) theory, in what ways social learning occurs in CIs; 2) to discover how various CoPs emerge and evolve in CIs to facilitate a collective journey in their learning process. Subsequently, the authors address the research questions: In what ways does social learning...
-
Chosen Methods Supporting Didacts of Descriptive Geometry
PublicationThe article presents reflections on the practical ways of supporting the teaching processes of descriptive geometry in the context of psychological theories of learning and motivation.
-
Real-Time stability monitoring for expansion of the UCTE synchronous area
PublicationW referacie przedstawiono zasady wykorzystania systemu WAMS dla potrzeb oceny zapasu stabilności lokalnej systemu elektroenergetycznego.
-
Zieleń miejska Gdyni okresu międzywojennego oraz problematyka jej zachowania = Urban greenery of Gdynia of interwar period and the issues of its retaining
PublicationURBAN GREENERY OF GDYNIA OF INTERWAR PERIOD AND THE ISSUES OF ITS RETAINING The subject of this article is the urban greenery arrangement in interwar Gdynia and the issues of its retaining after the II World War. The article will concern retaining the authenticity and integrity of the historic urban greenery of Gdynia, both greenery layouts and the plant material creating it. The author of the article will present in what...
-
Opinion about causes of framing of Kingston chest (box cooler) damage, on PSV vessel VS4411 DF-PSV (B-855)
PublicationThe subject of analysis is a damage of welded connection of box cooler framing segments, made as separate bars 50mm thickness, connected by the welds in corners. Studies of documents delivered by Customer shows cracks on the fusion of filet welds and twisting of box cooler frame. The subject of analysis is a damage of welded connection of box cooler framing segments, made as separate bars 50mm thickness, connected by the welds...
-
Radio Simulcasting at a Glance: a New Look at Broadcasting and Streaming Services
PublicationRadio is by far one of the most popular and accessible medium. With its availability it attracts listeners all around the world. There are numerous ways of delivering content to consumers. The present situation is characterized by the convergence of acoustics, computer science and telecommunications. This paper reviews the current status of radio broadcasting and streaming services. It describes a subjective study concerning different...
-
Flexoelectricity and apparent piezoelectricity of a pantographic micro-bar
PublicationWe discuss a homogenized model of a pantographic bar considering flexoelectricity. A pantographic bar consists of relatively stiff small bars connected by small soft flexoelectric pivots. As a result, an elongation of the bar relates almost to the torsion of pivots. Taking into account their flexoelectric properties we find the corresponding electric polarization. As a results, the homogenized pantographic bar demonstrates piezoelectric...
-
Experimental study and numerical optimization of tensegrity domes – A case study
PublicationThe paper deals with the design, experimental analysis and numerical optimization of tensegrity dome models. Two structures are analyzed – a Geiger system dome (preliminary dome), with PVC-U bars and PA6/PP/PET tendons and a Fuller system dome (target dome), with wooden bars and steel cables as tendons. All used materials are experimentally tested in terms of Young's modulus and yield stress values, the compressed bars are also...
-
Experimental study of the post tensioned prestressed concrete corbels
PublicationThe results of experimental investigation of 6 symmetrical double prestressed corbels of variable shear span to depth ratio and variable location of prestressing bars are presented in the paper. The post ten- sioned corbels were prestressed with Macalloy 1030 bars of 25 mm in diameter. The results of the tests were compared with the cracking and load carrying capacity of corbels reinforced with passive reinforce- ment. As a result...
-
Rapid simulation-driven design of miniaturised dual-band microwave couplers by means of adaptive response scaling
PublicationOne of the major challenges in the design of compact microwave structures is the necessity of simultaneous handling of several objectives and the fact that expensive electromagnetic (EM) analysis is required for their reliable evaluation. Design of multi-band circuits where performance requirements are to be satisfied for several frequencies at the same time is even more difficult. In this work, a computationally efficient design...
-
Regulacje prawne odnoszące się do testowania samochodów autonomicznych na drogach publicznych w Polsce i w Kalifornii
PublicationThe current level of technological advancement allows for predicting that in the near future autonomous technology may be successfully used for the production of self-driving cars. Many companies (not necessarily related to the automotive sector) have spotted the chance of future profits and thus started working on testing and development of autonomous vehicles. The initiation of work has indicated the lack of possibility to test...
-
Re-use of historic wooden verandas in Sopot, Poland
PublicationSopot is the best-known seaside resort in Poland. The city is unique with regard not only to its location and natural values, but also its interesting architecture, which dates back to the end of the 19th and the beginning of the 20th century. Wooden verandas are one of the characteristic features of Sopot architecture. Their origin is associated with the Swiss style, which was fashionable at the turn of the 20th century and quite...
-
The Brick Face of Modernism and Architecture of Gustav Oelsner
PublicationThere are many reasons that make the work of Gustav Oelsner worth to present. One of the reasons is comparison of two different ways of development of two cities, Gdynia (an exhibition of work of Gustav Oelsner was presented in Gdynia in April and May of 2011) and Altona, were Oelsner created his architecture. These two cities has grown at the side of their big neighbours, Gdansk and Hamburg. They are harbour cities and their...
-
Towards defragmented Lighting Design: concatenating research theories for effective use in design practices.
PublicationThis paper aims to provide guidelines for transferring design research to practice in the realm of lighting. It is based on the premise that design research in lighting should function as a development of practice, instead of being a distraction to it. Design research refers to the scholarly inquiry that seeks to advance design by studying and improving it in systematic and scientific ways by expanding, testing and operationalizing...
-
Analysis of the cyclic load-unload-reload tests of VALMEX aged fabric
PublicationThe paper presents mechanical response of the VALMEX fabric during the cyclic loading-unloading and re-loading experiments. Two types of the aged material used for nearly 20 years as the roofing of the Forest Opera in Sopot (Poland) have been tested. The results have been separately obtained for the warp and fill di-rections. The comparative analysis has revealed that the material aged in service is more durable in the fill di-rection,...
-
Dzielnica Reprezentacyjna Gdyni i jej powojenne oraz współczesne interpretacje
PublicationThe concept of the Premiere District in Gdynia was first conceived in the 1920s and from that time on it constantly accompanied the history of the city. It derivated from the idea of creating a symbol of Poland's regaining independence after the first World War and the successful creation of the new port and city on the Baltic coast. As the result of that development, Gdynia was named the maritime capital of Poland and was treated...
-
Nowy Orlean : zrobmy to porządnie
PublicationOpis społecznego projektu odbudowy dzielnicy Lower Ninth Ward, zniszczonej przez huragan Katrina w 2005 roku w Nowym Orleanie, realizowanego przez fundację Make it Right.
-
THE EFFECT OF WOOD DRYING METHOD ON THE GRANULARITY OF SAWDUST OBTAINED DURING THE SAWING PROCESS USING THE FRAME SAWING MACHINE
PublicationThe experimental results of the study focused on the effect of drying processes of warm air drying at the temperature of 6580°C and warm air-steam mixture drying at the temperature of 105°C of pine and beech wood to the size of sawdust grains created by cutting using RPW 15M frame saw is presented in the paper. Particle size analysis of dry sawdust was performed using two methods - screening method and optical method based on...
-
Influence of selected WMA additives on viscoelastic behaviour of asphalt mixes and pavements
PublicationWarm mix asphalt additives are effective in decreasing production, laying and compaction temperatures of asphalt mixes. However, there are still questions concerning influence of warm mix additives on properties of asphalt mixes and pavement performance. This paper presents results of the comprehensive research of viscoelastic behaviour of asphalt mixes and pavement structures with layers made with warm mix asphalt additives at...