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Number of results: 102
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Abstract

Water is a strategic material. Recycling is an important component of balancing its use. Deep-bed filtration is an inexpensive purification method and seems to be very effective in spreading water recovery. Good filter designs, such as the fibrous filter, have high separation efficiency, low resistance for the up-flowing fluid and high retention capacity. However, one of the substantial problems of this process is the biofouling of the filter. Biofouling causes clogging and greatly reduces the life of the filter. Therefore, the melt-blown technique was used for the formation of novel antibacterial fibrous filters. Such filters are made of polypropylene composites with zinc oxide and silver nanoparticles on the fiber surface. These components act as inhibitors of bacterial growth in the filter and were tested in laboratory and full scale experiments. Antibacterial/bacteriostatic tests were performed on Petri dishes with E. coli and B. subtilis. Full scale experiments were performed on natural river water, which contained abiotic particles and mutualistic bacteria. The filter performance at industrial scale conditions was measured using a particle counter, a flow cytometer and a confocal microscope. The results of the experiments indicate a significant improvement of the composite filter performance compared to the regular fibrous filter. The differences were mostly due to a reduction in the biofouling effect.
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Abstract

The paper proposes a procedure which enables to determine selected geometric and operating parameters for twin-fluid liquid-to-air atomisers with internal mixing. The presented approach assumes that in order to ensure proper operation of an atomiser it is necessary to design its structure and flow parameters in such a way so that the flow inside the mixing chamber has a dispersive character. In order to calculate a required exhaust cross-section for the analysed atomiser, conditions within the exhaust plane: pressure, density and outflow velocity were estimated. In order to determine diameter and number of orifices supplying the liquid to the mixing chamber of the investigated atomiser type, a multi-parameter analysis based on numerical fluid mechanics was performed. The final part of the paper presents selected results obtained from experimental stand measurements made on an atomiser designed according to the presented procedure.
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Abstract

The aim of this paper is to present an in-pipe modular robotic system that can navigate inaccessible industrial pipes in order to check their condition, locate leakages, and clean the ventilation systems. The aspects concerning the development of a lightweight and energy efficient modular robotic system are presented. The paper starts with a short introduction about modular inspection systems in the first chapter, followed by design aspects and finalizing with the test of the developed robotic system.
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Abstract

The paper focuses on different approaches to the safety assessment of concrete structures designed using nonlinear analysis. The method based on the concept of partial factors recommended by Eurocodes, and methods proposed by M. Holicky, and by the author of this paper are presented, discussed and illustrated on a numerical example. Global safety analysis by M. Holicky needs estimation of the resistance coefficient of variation from the mean and characteristic values of resistance, and requires two separate nonlinear analyses. The reliability index value and the sensitivity factor for resistance should be also identified. In the method proposed in this paper, the resistance coefficient of variation necessary to calculate the characteristic value of resistance may be adopted from test results and the resultant partial factor for materials properties, and may be calculated according to Eurocodes. Thus, only one nonlinear analysis from mean values of reinforcing steel and concrete is required.
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Abstract

In the paper a research on cost-effective optimum design boiling temperature for Organic Rankine Cycle utilizing low-temperature heat sources is presented. The ratio of the heat exchanger area of the boiler to the power output is used as the objective function. Analytical relations for heat transfer area as well power of the cycle are formulated. Evaporation temperature and inlet temperature of the heat source medium as well its mass flow rate are varied in the optimization method. The optimization is carried out for three working fluids, i.e. R 134a, water and ethanol. The objective function (economics profitability, thermodynamic efficiency) leads to different optimal working conditions in terms of evaporating temperature. Maximum power generation in the near-critical conditions of subcritical ORC is the highest. The choice of the working fluid can greatly affect the objective function which is a measure of power plant cost. Ethanol exhibits a minimum objective function but not necessarily the maximum cycle efficiency.
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Abstract

The box wing system is an unconventional way to connect the lifting surfaces that the designers willingly to use in prototypes of new aircrafts. The article present a way to quickly optimize the wing structure of box wing airplane that can be useful during conceptual design. At the beginning, there is presented theory and methods used to code optimization program. Structure analysis is based on FEM beam model, which is sufficient in conceptual design. Optimization is performed using hybrid method, connection of simple iteration and gradient descent methods. Finally, the program is validated by case study.
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Abstract

The aim of the study is to compare flexible pavement design lifespans and the main factors which create their values for a standard structure and one with an anti-fatigue course AF at different parameter values of pavement and its load, relevant to their design processes. Depending on the mixture used for the anti-fatigue course or the course thickness, durability improvement of the pavement (compared to the durability of a standard structure) can be obtained by extending the design lifespan of the asphalt base course or by extending the design lifespan of the AF course. On sections with predominantly slow traffic, the lifespan decreases significantly compared to sections with typical vehicle speed – the relative decrease is greater if anti-fatigue course is applied.
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Abstract

Zinc plant residue is a hazardous waste which contains high quantity of nickel and other valuable metals. Process parameters such as reaction time, acid concentration, solid-liquid ratio, particle size, stirring speed and temperature for nickel extraction from this waste were optimized using factorial design. Main effects and their interactions were obtained by the analysis of variance ANOVA. Empirical regression model was obtained and used to predict nickel extraction with satisfactory results and to describe the relationship between the predicted results and the experiment results. The important parameters for maximizing nickel extraction were identifi ed to be a leaching time solid-liquid ratio and acid concentration. It was found that above 90% of nickel could be extracted in optimum conditions.
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Abstract

This work examines the reduced-cost design optimization of dual- and multi-band antennas. The primary challenge is independent yet simultaneous control of the antenna responses at two or more frequency bands. In order to handle this task, a feature-based optimization approach is adopted where the design objectives are formulated on the basis of the coordinates of so-called characteristic points (or response features) of the antenna response. Due to only slightly nonlinear dependence of the feature points on antenna geometry parameters, optimization can be attained at a low computational cost. Our approach is demonstrated using two antenna structures with the optimum designs obtained in just a few dozen of EM simulations of the respective structure.
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Abstract

In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM) simulation model of the structure that includes (for reliability) an SMA connector. Another problem is a large number of geometry parameters (nineteen). For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.
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Abstract

The chuch dedicated to The Holy Spirit, erected in Wrocław, in housing estate Huby, was created during the communist period, hence it was very difficult to design it, and to build. But it was also the period close to the collapse of this regime, so communist leaders were pressed to be more tolerant towards human rights than before, including the religious freedom and towards building new churches. The author of the church mentioned – a very active political oppositionist – when designing the strongly innovative church building, was simultaneously forced by fate to fight formal difficulties caused by oppressive rulers. Author makes the reader closer to those complicated double troubles: artistic, parallel to the political. Finally, the church building was happily completed, then became widely popular and accepted.
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Abstract

We study an elegant snap system with only one nonlinear term, which is a quadratic nonlinearity. The snap systemdisplays chaotic attractors,which are controlled easily by changing a system parameter. By using analysis, simulations and a real circuit, the dynamics of such a snap system has been investigated. We also investigate backstepping based adaptive control schemes for the new snap system with unknown parameters.
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Abstract

In the paper, a procedure for precise and expedited design optimization of unequal power split patch couplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to the circuit operating at the requested frequency and featuring a required power split. At the same time, the design process is supposed to be computationally efficient. The proposed methodology involves two types of auxiliary models (surrogates): an inverse one, constructed from a set of reference designs optimized for particular power split values, and a forward one which represents the circuit S-parameter gradients as a function of the power split ratio. The inverse model directly yields the values of geometry parameters of the coupler for any required power split, whereas the forward model is used for a post-scaling correction of the circuit characteristics. For the sake of illustration, a 10-GHz circular sector patch coupler is considered. The power split ratio of the structure is re-designed within a wide range of ��6 dB to 0 dB. As demonstrated, precise scaling (with the power split error smaller than 0.02 dB and the operating frequency error not exceeding 0.05 GHz) can be achieved at the cost of less than three full-wave EM simulations of the coupler. Numerical results are validated experimentally.
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Abstract

City is a formal expression of social relations. It is a kind of ethos and dreams connected with history and identity of individuals. It is a structure with thousands of meanings. The opportunities it creates can lead to an outstanding civilization. At the same time it reveals all negative aspects of living. City is a collection of separate individuals combined with common perception of spatial affi liation and identity development. It is worth writing about city because despite its well-defi ned value it is an elusive being. In spite of being a kind of collective needs it is still on the move, transforms all the time reflecting human emotions. Existence of city as a phenomena itself is a symbol of realization of people’s most basic needs and the history of its development shows growing complication and diversification of expectations related to it. City along with is diversity reflects human beings of a particular time. It is a spotlight in which both successes and failures of communities and individuals in each epoch can be seen. Thanks to its interdisciplinary character it can be perceived as multidimensional place. It is a multifaceted organism with high hopes and unlimited opportunities. Differences in perception which are due to a number of its users results in a wide range of problems and expectations. Expectations of local communities and individuals of a whole city vary. As a result, what we call a city landscape must be very vague and differs depending on a particular field which is taken into consideration. The number of opportunities and city-related issues is infi nite. In the dissertation below, however, three factors are the crucial ones: structure, meaning and city phenomena as a landscape. Thanks to the interpretation of model and genius loci as well as defining social expectations we have managed to conceive the phenomena of spatial identity. We have decided on this method referring directly to the concept of landscape. City is in here widely defined between urban aspects of landscape and city landscape. We have tried to understand what city is in terms of landscape, where it comes from and where it goes to. It is a trial of translation the Gaugin’s method: where are we from? Who are we? Where are we going to? into the language of present perception of some particular aspects of town planning. We live at times of the unprecedented technological change which is followed by a social change. It all must have an impact on how city is perceived, what it looks like, how it is to live there and what it is going to be like – what the future has in store. We have tried to bring the reader’s attention to the problems and issues which had appeared before the advent of reality we live in. We have focused on what may have led to a kind of city crisis at the edge of 19th and 20th centuries and some radical solutions trying to overcome the arisen problems and its consequences today. Both its pompous character and sentimentalism of town planning and architecture in the early 20th century have made us be bored with form which is felt in many parts of the world even today. Another aspect of our work covers understanding city in social terms as well as contemporary and future solutions. We are of the opinion it is worth asking questions referring to the future and at the same time regarding its current state and recent past. It is commendable to look for particular tools and solutions. Three dimensions which are covered by the book are figurative. Structure – which is everything we perceive as a kind of a template, identifi cation – we assign to city. It is responsible for recognition, adaptation to some forms by which we defi ne space. Meaning is a step forward. While the structure’s equivalent is „I can see”, the meaning equals to „I know”. Meaning does not exist as a city without structure just like structure does not exist without meaning. Things don’t just exist, they have some characteristics and purpose and it refers to trees, buildings and all other urban elements constituting city in all steady and temporary aspects and time dimensions. Meaning is also interpretation and emotion regarding both community and individual. It is the answer to the question „why?” Some particular places and spaces are linked to some particular values which identify them. This system of values is a must to be able to interpret what space we are dealing with and its diagnosis. Meaning is very much about social aspect too. It has to do with perception and remembering city and it is connected with knowledge, tradition and culture of places. Another aspect linked to relations in city landscape combines other aspects and constitutes something to which city refers to. Phenomena is contribution and verifi cation. The way city works is fundamental to all city residents and users. A key to such understanding a city is the term of genius loci. By singling out objects, order, time, character and light we are able to widely identify essence of space and particular places. The graphic model by Panofsky acts here as a verifying tool. City landscape as a form is of great importance here. The sense of beauty is as essential as the way the city works. Social perception of city is not only shaped by the way it is used, but also by the fact what city is like and how it is perceived. Spatial order is an incredibly important factor understood here as everything what accommodates vaguely defi ned beauty and what is connected with its particular structure, history and identity. All these factors contribute to the value of city landscape. When it comes to city landscape studies social aspect is emphasized by the impact of humanities, especially sociology, which perfectly shows expectations related to space. Cities are built and seen in the context of particular tradition, culture and history. Their skyline and ways of functioning are embedded in mentalities of societies which they represent. Despite their diversity from the global point of view they are susceptible to similar trends resulting in crisis or prosperity periods. They are economic archetypes of success.
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Abstract

This article reflects on the results the use and eff ectiveness of design coding as urban design / development tool, focusing on the roles of and the relationships between the different actors playing parts in the in the design coding process: the administration, the investors, the designers, the politics and the community. It reveals the gap in professional circles that impacts the development process, which, deepened by the continuous battle between the creative, the market-driven and the regulatory modes praxis. The article is polemical in that it points to the three main parties of this collective process, referring to is as the creative, market and regulatory tyranny. The author proposes that design coding, if used correctly, could be an effective tool regulating the essentials of urbanism, leaving room for creativity and enhanced market value. Design coding as such results in improvement of the quality of both urbans space and housing architecture.
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Abstract

The article describes the design principles, the course of work on the project and the implementation of the Nowe Żerniki district, in the context of the theory of sustainable housing complexes. By comparing the settlement to the Aspern Seestadt, which is considered to be the leading European example of new district development, the author tries to find out, if Nowe Żerniki meets the latest European urban standards and can be called innovative on a European scale. Not only the final shape of the settlement was assessed, but also the design process and functional assumptions of the estate.
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Abstract

The article presents Charles Taylor’s critical philosophy of language and it reviews his recent book on the human linguistic capacity. Critical philosophy of language is understood here as a broad (philosophical, social and political) perspective on language characterized by multifaceted concern with the linguistic and cognitive mechanisms involved in language use. The paper discusses Taylor’s interest in language and philosophy of language, and focuses on his seminal distinction between the ‘designative-instrumental’ and ‘constitutive-expressive’ theories of language. In the former theory language is understood within the confi nes of Cartesian representational epistemology, whereas in the latter language constitutes meaning and shapes human experience (one of the features important for defi ning the critical approach to philosophy of language).
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Abstract

Thin-walled bars currently applied in metal construction engineering belong to a group of members, the cross-section resistance of which is affected by the phenomena of local or distortional stability loss. This results from the fact that the cross-section of such a bar consists of slender-plate elements. The study presents the method of calculating the resistance of the cross-section susceptible to local buckling which is based on the loss of stability of the weakest plate (wall). The "Critical Plate" (CP) was identified by comparing critical stress in cross-section component plates under a given stress condition. Then, the CP showing the lowest critical stress was modelled, depending on boundary conditions, as an internal or cantilever element elastically restrained in the restraining plate (RP). Longitudinal stress distribution was accounted for by means of a constant, linear or non-linear (acc. the second degree parabola) function. For the critical buckling stress, as calculated above, the local critical resistance of the cross-section was determined, which sets a limit on the validity of the Vlasov theory. In order to determine the design ultimate resistance of the cross-section, the effective width theory was applied, while taking into consideration the assumptions specified in the study. The application of the Critical Plate Method (CPM) was presented in the examples. Analytical calculation results were compared with selected experimental findings. lt was demonstrated that taking into consideration the CP elastic restraint and longitudinal stress variation results in a more accurate representation of thin-walled element behaviour in the engineering computational model
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Abstract

This paper studied the concept of the habitability of buildings as a sustainability factor in the living environment, particularly in the city of Bogotá. The habitability factor stems from the relationship between human beings, the cultural dimension and the environment. Thus, we can say that the habitability factor is an important element in the building design process. Currently in Bogotá there are buildings that do not meet the requirements of the population. In Bogotá only 40% of buildings are of a good quality and a great number of newly produced buildings have made for lower quality living spaces. Consequently, it is important to give an adequate response to these kinds of demands. For thase reasons, this study created a model to evaluate the habitability factor of buildings. This model gives some guidelines for designing sustainable buildings and implementing stategies to design a better urban habitat. Finally, the Habitability model was tested as a pilot in the Primero de Mayo neighbourhood, which is located in the fourth district of Bogotá. The neighbourhood was classified as a cultural heritage site by city hall.
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Abstract

In the recent years, chaotic systems with uncountable equilibrium points such as chaotic systems with line equilibrium and curve equilibrium have been studied well in the literature. This reports a new 3-D chaotic system with an axe-shaped curve of equilibrium points. Dynamics of the chaotic system with the axe-shaped equilibrium has been studied by using phase plots, bifurcation diagram, Lyapunov exponents and Lyapunov dimension. Furthermore, an electronic circuit implementation of the new chaotic system with axe-shaped equilibrium has been designed to check its feasibility. As a control application, we report results for the synchronization of the new system possessing an axe-shaped curve of equilibrium points.
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Abstract

In recent years, due to the growing importance of eco-design and tightening EU regulations entrepreneurs are required to implement activities related to environmental protection. It influences the development of methods and tools enabling the implementation of eco-design into practice, which are increasingly used by modern information technologies. They are based on intelligent solutions that allows them to better match the requirements of designers and allows for the automation of processes, and in some cases they are able to do the work themselves, replacing designers. Details are useful in areas that require calculations, comparisons and making choices, which is the process of eco-design. The paper describes methodology of pro-ecological product design oriented towards recycling, based on agent technology, enables the design of environmentally friendly products including recycling. The description of the methodology was preceded by a literature analysis on the characteristics of tools supporting eco-design and the process of its development was presented. The proposed methodology can be used at the design stage of devices to select the best product in terms of ecology. It is based on the original set of recycling indicators, used to evaluate the recycling of the product, ensure the ability to operate in a distributed design environment, and the use of data from various CAD systems, allows full automation of calculations and updates (without user participation).
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Abstract

In the paper an application of evolutionary algorithm to design and optimization of combinational digital circuits with respect to transistor count is presented. Multiple layer chromosomes increasing the algorithm efficiency are introduced. Four combinational circuits with truth tables chosen from literature are designed using proposed method. Obtained results are in many cases better than those obtained using other methods.
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Abstract

Molecular motors are nature’s nanomachines, and are the essential agents of movement that are an integral part of many living organisms. The supramolecular machine, called the nuclear pore complex (NPC), controls the transport of all cellular material between the cytoplasm and the nucleus that occurs naturally in all biological cells. In the presence of appropriate chemical stimuli, the NPC opens or closes, like a gating mechanism, and permits the flow of material into and out of the nucleus. As a first step in understanding the design characteristics of the NPC, nanoscale studies were conducted to understand the transport characteristics of an idealized NPC model using CFD analysis, discrete element transport and coupled fluid-solid analysis. Results of pressure and velocity profiles obtained from the models indicate that the fluid density, flexibility of walls and the geometry of the flow passage are important in the design of NPC based nano- and micro-motors.
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Abstract

Based on mathematical modelling and numerical simulations, a control strategy for a Molten Carbonate Fuel Cell Hybrid System (MCFC-HS) is presented. Adequate maps of performances with three independent parameters are shown. The independent parameters are as follows: stack current, fuel mass flow and compressor outlet pressure. Those parameters can be controlled by external load, fuel valve and turbine-compressor shaft speed, respectively. The control system is purposed to meet many constraints: e.g. stack temperature, steam-to-carbon ratio, compressor surge limitation, etc. The aim is to achieve maximum efficiency of power generated within these constraints. Governing equations of MCFC-HS modelling are given. An operational line of the MCFC-GT system is presented which fulfils several constraints (temperature difference, cell temperature, etc.) The system is able to achieve efficiency of more than 62% even in part-load operation.
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