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Wyniki wyszukiwania dla: large-scale machining
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Analyses of Shear Angle in Orthogonal Cutting of Pine Wood
PublikacjaThe determination of energy effects for wood machining processes, such as cutting power and cutting forces, is very useful in designing of manufacture process of wooden products. A more accurate prediction of cutting forces requires a correct determination of the shear angle value, which can be determined using various models. In this article, shear angle values for an orthogonal linear cutting process of pine wood are determined. The...
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Thermal and technological aspects of double face grinding of C45 carbon steel
PublikacjaIn grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the...
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Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
PublikacjaThis study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol...
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Model based evaluation of plant improvement at a large wastewater treatment plant (WWTP)
PublikacjaIn this work, the effect of the improvement carried out at a large-scale wastewater treatment plant (WWTP) was evaluated, by means of modelling works, with the aim to determine the influence of the modernization over the process performance. After modernization, the energy consumption due to the aeration decreased about a 20% maintaining the effluent quality. In order to double-check the good effluent quality, modelling works were...
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Nonlinear phenomena of small-scale sound in a gas with exponential stratification
PublikacjaThe nonlinear dynamics of perturbations, quickly varying in space, with comparatively large characteristic wavenumbers k: k>1/H, is considered. H is the scale of density and pressure reduction in unperturbed gas, as the coordinate (H is the so-called height of the uniform equilibrium gas). Coupling nonlinear equations which govern the sound and the entropy mode in a weakly nonlinear flow are derived. They describe the dynamics...
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The Influence of Workpiece Hardness on Plate Temperature during One Side Lapping
PublikacjaLapping leads to a surface with low roughness and high precision. Because of required parts accuracy tool flatness is the key to the successful machining. To avoid its excessive thermal expansion, plate temperature research was taken. The goal was to determine the correlation between the basic lapping conditions and wheel temperature. In work Bulsara et al. authors developed model to estimate the maximum and average temperature...
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Non-conventional approach in single-sided lapping process: kinematic analysis and parameters optimization
PublikacjaThe lapping process is strongly affected by a number of input parameters. One of the fundamental mechanical processes in lapping is the abrasive effect of particles. In order to examine the influence of the kinematic parameters on the lapping uniformity of unconventional single-sided machine, numerical simulations of particles sliding trajectories are performed. Changing the kinematic parameters, e.g., rotational velocities or...
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The Possibilities of Improving the Fatigue Durabilityof the Ship Propeller Shaft by Burnishing Process
PublikacjaHeavily loaded structural elements operating in a corrosive environment are usuallyquickly destroyed. An example of such an element is a ship propeller operating in a seawaterenvironment. This research presents a fatigue resistance test performed on elements operating inseawater. Different processing parameters applied on the samples in particular were compared withthe specimens whose surface had been burnished differently and...
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Ryszard S. Romaniuk profesor
OsobyProfessor of Electronics, Computer and Communications Engineering at Warsaw University of Technology, Poland; Eisenhower Fellow, Philadelphia, MA USA; SPIE Fellow, Bellingham, WA USA; Editor-in-Chief, International Journal of Electronics and Telecommunications, Polish Academy of Sciences; Photonics Spectra Magazine, EAB Member; ORCID; GoogleScholar; ResearchGate; Publons; Scopus; PW; OWPW; PBN; NaukaPolska; IN;
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Simulation of wood structure geometry after machining
PublikacjaW niniejszym artykule została przedstawiona nowa metoda trójwymiarowych symulacji geometrii powierzchni drewna. Zaprezentowano wpływ parametrów obróbkowych oraz drgań podczas strugania obrotowego drewna. Chropowatość powierzchni była charakteryzowana poprzez parametry profilu chropowatości Ra oraz Rz. Posuw na ostrze oraz średnica narzędzia są najbardziej wpływającymi czynnikami na wielkość nierówności podczas maszynowej obróbki...
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Planning cellular machining systems for lean production.
PublikacjaRozważano zagadnienie projektowania struktur systemów obróbki o zdeterminowanych możliwościach technologicznych, odpowiadających wymaganiom oszczędnej produkcji. Przedstawiono model matematyczny wyznaczania struktur systemów grupowego wytwarzania, wykorzystujący zasady formalizmu relacji i grafów rozmytych. Zawarto wyniki badań symulacyjnych efektywności procesów wytwarzania określonego spektrum przedmiotowego, przebiegających...
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Friction and Lubrication of Large Tilting-Pad Thrust Bearings
PublikacjaFluid film bearings have been extensively used in the industry because of their unbeatable durability and extremely low friction coefficient, despite a very low coefficient of friction dissipation of energy being noticeable, especially in large bearings. Lubricating systems of large tilting pad thrust bearings utilized in large, vertical shaft hydrogenerators are presented in this paper. A large amount of heat is generated due...
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Dynamic Research of Masonry Vault in a Technical Scale
PublikacjaThe paper presents preliminary results of dynamic tests of the masonry barrel vault in a technical scale. Experimental studies are intended to identify material properties of homogenized masonry vaults under dynamic loads. The aim of the work is to create numerical models to analyse vault’s dynamic response to dynamic loads in a simplest and accurate way. The process of building the vault in a technical scale is presented in the...
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Circular saw vibrations or dynamics of the spindle
PublikacjaSawing of wood with circular saws is a typical example of cutting with multi-blade tools. In that kind of cutting, theposition accuracy of following tool blades is a crucial factor which affects the cutting process and machining final effects.Position tooth errors may cause deterioration in cutting conditions, changes in loads of individual teeth and the tool as a whole,and also a decrease in accuracy and surface quality after...
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Modeling of Surface Roughness in Honing Processes by UsingFuzzy Artificial Neural Networks
PublikacjaHoning processes are abrasive machining processes which are commonly employed to improve the surface of manufactured parts such as hydraulic or combustion engine cylinders. These processes can be employed to obtain a cross-hatched pattern on the internal surfaces of cylinders. In this present study, fuzzy artificial neural networks are employed for modeling surface roughness parameters obtained in finishing honing operations. As...
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Lateral forces determine dimensional accuracy of the narrow‑kerf sawing of wood
PublikacjaThe shrinking global forest area limits the supply of industrially usable raw resources. This, in combination with the ever‑increasing consumption of timber due to population growth can lead to the lack of a positive balance between the annual volumetric growth and consumption of wood. An important innovation toward increasing environmental and economic sustainability of timber production is to reduce the volume of wood residues...
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Reduction in Errors in Roughness Evaluation with an Accurate Definition of the S-L Surface
PublikacjaCharacterization of surface topography, roughly divided into measurement and data analysis, can be valuable in the process of validation of the tribological performance of machined parts. Surface topography, especially the roughness, can respond straightly to the machining process and, in some cases, is defined as a fingerprint of the manufacturing. When considering the high precision of surface topography studies, the definition...
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Smart Weighing Scale with Feet-Sampled ECG
PublikacjaIn a smart home, health and well-being monitoring systems could be embedded in everyday devices providing a pervasive care. A home bathroom scale is an example of such a device, typically used to measure body weight and very often its composition (e.g. body water/fat percentage). In this paper, we analyzed a potential use of the bathroom scale to measure electrocardiogram (ECG) from electrodes located on the scale's tile. In particular...
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Stability by linear approximation for time scale dynamical systems
PublikacjaWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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Comparison of various speech time-scale modificartion methods
PublikacjaThe objective of this work is to investigate the influence of the different time-scale modification (TSM) methods on the quality of the speech stretched up using the designed non-uniform real-time speech time-scale modification algorithm (NU-RTSM). The algorithm provides a combination of the typical TSM algorithm with the vowels, consonants, stutter, transients and silence detectors. Based on the information about the content and...
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The Large Customer Reactive Power Control Possibilities
Publikacjan this paper the authors wish to draw attention to the rationale for, and the possibility of, the use of local reactive power sources by the Transmission Node Master Controller (TNMC). Large Customers (LC) are one of the possible reactive power sources. The paper presents the issues related to the need for coordination between the control systems installed in the LC network, and coordination between control systems of the LC as...
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Numerical solutions for large deformation problems in geotechnical engineering
PublikacjaThe problem of large deformations often occurs in geotechnical engineering. Numerical modeling of such issues is usually complex and tricky. The chosen solution has to implicate soil-soil and soil-structure interactions. In this paper, a review of the most popular numerical methods for large deformation problems is presented. The Coupled Eulerian-Lagrangian (CEL) method, the Arbitrary Lagrangian-Eulerian (ALE) method, the Smoothed...
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Tendencies in abrasive machining with lapping kinematics - experimental studies
PublikacjaW pracy przedstawiono tendencje rozwoju obróbki ściernej z wykorzystaniem kinematyki docierania. Zaprezentowano wyniki badań szlifowania specjalnymi narzędziami w układzie docierarki jedno- i dwutarczowej.
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Analysis of machining marks curvature in single disk lapping
PublikacjaW referacie przedstawiono wyniki badań symulacyjnych i eksperymentalnych dotyczących wyznaczania i oceny krzywizny śladów obróbkowych po obróbce mikroszlifowaniem z kinematyką docierania jednotarczowego.
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Molecular dynamics simulations of ultraprecision machining of fcc monocrystals
PublikacjaArtykuł zawiera wyniki wielkoskalowych symulacji dynamiczno-molekularnych ultraprecyzyjnego skrawania monokryształów metali niedeformowalnym narzędziem. Zmiennymi parametrami symulacji były: szybkość i głębokość skrawania, temperatura, orientacja krystalograficzna skrawanego kryształu oraz kształt narzędzia.Analizie poddano zmiany strukturalne w obrabianym materiale.
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Machining of the flat surfaces with abrasive-metallic lapping tools.
PublikacjaPrzedstawiono konstrukcje narzędzi ścierno-metalowych do obróbki powierzchni płaskich na docierarkach jednotarczowych. Przeprowadzono badania wydajności i jakości powierzchni elementów ceramicznych o małych gabarytach.
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Development of cluster analysis methodology for identification of model rainfall hyetographs and its application at an urban precipitation field scale
PublikacjaDespite growing access to precipitation time series records at a high temporal scale, in hydrology, and particularly urban hydrology, engineers still design and model drainage systems using scenarios of rainfall temporal distributions predefined by means of model hyetographs. This creates the need for the availability of credible statistical methods for the development and verification of already locally applied model hyetographs....
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On the Peano Theorem for Some Functional Differential Equations on Time Scale
PublikacjaThe Peano Theorem for some functional differential equations on time scale is proved. Assumptions are of Caratheodory type. Two counter examples for false Peano theorems in the literature are presented.
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Topic 1: Transformations / Spatial form design, scale 1:1
Kursy OnlineBrief description: The subject matter of the spatial form design classes is transformation. First, a black square becomes a flat graphic composition, which is then converted to color. The final stage of the transformation process is a spatial object, which is by assumption devoid of any utilitarian functions. Course content / classes schedule: 1. Graphic. The task is to create an achromatic flat composition in the contrast...
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A scale with ECG measurements capability for home cardiac monitoring
PublikacjaPresented device -a scale developed for enabling extra measurements, in addition to body weight and composition, the electrical activity of the heart (electrocardiogram - ECG) and the level of oxygen saturation in the blood SaO2. Electrical activity is recorded in the form of six leads, socalled - limb leads. The device allows measurement of all standard limb leads and without the need for additional procedures. ECG, although the...
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Friction Stir Welding of Aluminum in the Aerospace Industry: The Current Progress and State-of-the-Art Review
PublikacjaThe use of the friction stir welding (FSW) process as a relatively new solid-state welding technology in the aerospace industry has pushed forward several developments in different related aspects of this strategic industry. In terms of the FSW process itself, due to the geometric limitations involved in the conventional FSW process, many variants have been required over time to suit the different types of geometries and structures,...
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Corrosion Resistance and Surface Bioactivity of Ti6Al4V Alloy after Finish Turning under Ecological Cutting Conditions
PublikacjaThe influence of cooling conditions and surface topography after finish turning of Ti6Al4V titanium alloy on corrosion resistance and surface bioactivity was analyzed. The samples were machined under dry and minimum quantity lubrication (MQL) conditions to obtain different surface roughness. The surface topographies of the processed samples were assessed and measured using an optical profilometer. The produced samples were subjected...
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Worm Gear Drives with Improved Kinematic Accuracy
PublikacjaThis paper presents the fundamentals of the design and applications of new worm gear drive solutions, which enable the minimisation of backlash and are characterised by higher kinematic accuracy. Different types of worm surfaces are briefly outlined. Technological problems concerning the principles of achieving a high degree of precision in machining are also described. Special attention is paid to the shaping of conical helical...
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Tool Wear Monitoring Using Improved Dragonfly Optimization Algorithm and Deep Belief Network
PublikacjaIn recent decades, tool wear monitoring has played a crucial role in the improvement of industrial production quality and efficiency. In the machining process, it is important to predict both tool cost and life, and to reduce the equipment downtime. The conventional methods need enormous quantities of human resources and expert skills to achieve precise tool wear information. To automatically identify the tool wear types, deep...
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Music Data Processing and Mining in Large Databases for Active Media
PublikacjaThe aim of this paper was to investigate the problem of music data processing and mining in large databases. Tests were performed on a large data-base that included approximately 30000 audio files divided into 11 classes cor-responding to music genres with different cardinalities. Every audio file was de-scribed by a 173-element feature vector. To reduce the dimensionality of data the Principal Component Analysis (PCA) with variable...
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Analytical eco-scale for assessing the greenness of analytical procedures
PublikacjaWe propose the analytical eco-scale as a novel comprehensive approach to evaluating the greenness of analytical methodology. It is based on assigning penalty points to parameters of an analytical process that are not in agreement with the ideal green analysis. This approach compares different parameters and different steps of the analytical process. Traditional green chemistry metrics 9e.g. Atom Economy, E-factor and Reaction Mass...
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Parallelization of large vector similarity computations in a hybrid CPU+GPU environment
PublikacjaThe paper presents design, implementation and tuning of a hybrid parallel OpenMP+CUDA code for computation of similarity between pairs of a large number of multidimensional vectors. The problem has a wide range of applications, and consequently its optimization is of high importance, especially on currently widespread hybrid CPU+GPU systems targeted in the paper. The following are presented and tested for computation of all vector...
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Application of Web-GIS for Dissemination and 3D Visualization of Large-Volume LiDAR Data
PublikacjaThe increasing number of digital data sources, which allow for semi-automatic collection and storage of information regarding various aspects of life has recently granted a considerable rise in popularity to the term “Big data”. As far as geospatial data is concerned, one of the major sources of Big data are Light Detection And Ranging (LiDAR) scanners, which produce high resolution three-dimensional data on a local scale. The...
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A method for counting people attending large public events
PublikacjaThe algorithm for people counting in crowded scenes, based on the idea of virtual gate which uses optical flow method is presented. The concept and practical application of the developed algorithm under real conditions is depicted. The aim of the work is to estimate the number of people passing through entrances of a large sport hall. The most challenging problem was the unpredicted behavior of people while entering the building....
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The influence of variants of finishing machining on scheduling of shaft components manufacturing
PublikacjaIn the paper variants of technological processes were presented to the study for piston rods and rams of hydraulic cylinders taking issues into consideration scheduling of course of the production in flexible manufacturing cell. At the carried study an attempt of the estimation of the influence of technological variants on the effectiveness to manufacture the flexible manufacturing system on the basis of preliminary schedules of...
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Ecological trends in machining as a key factor in sustainable production – A review
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Can Historic Interiors with Large Cubature be Turned Acoustically Correct?
PublikacjaHistoric interiors with large cubature, such as reception, theatrical, and concert halls, need to be renovated periodically if they are to be preserved as cultural heritage for future generations. In such cases it is necessary to maintain appropriate balance between requirements imposed by heritage conservation authorities office which are usually being given a higher priority, applicable safety regulations, and the comfort of...
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Generation of large finite-element matrices on multiple graphics processors
PublikacjaThis paper presents techniques for generating very large finite-element matrices on a multicore workstation equipped with several graphics processing units (GPUs). To overcome the low memory size limitation of the GPUs, and at the same time to accelerate the generation process, we propose to generate the large sparse linear systems arising in finite-element analysis in an iterative manner on several GPUs and to use the graphics...
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Time-scale modification of speech signals for supporting hearing impaired schoolchildren
PublikacjaA study of time scale modification algorithmsapplied to hearing impaired schoolchildren supporting ispresented. Variety of algorithms are considered, namely:overlap and add, two variations of synchronized overlapand add, and the phase vocoder. Their effectiveness as wellas real-time processing capabilities are examined.
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Smooth Particle Hydrodynamics (SPH) approach in simulating large penetration into soil
PublikacjaA study of Smooth Particle Hydrodynamics (SPH) approach for predicting large soil deformation is presented. Theoretical basics of SPH method, including the equations governing, discussion of the importance of smoothing function length, contact formulation, boundary treatment and finally utilization in hydrocodes simulations are presented. An application of SPH to a real case of large penetrations (crater creating) into soil caused...
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Improvement of ships seakeeping performance by application of the full-scale cfd simulations
PublikacjaThe ship’s fuel economy is increasingly important. The paper presents the effect of redesigning a case study ship for increasing seakeeping performance. Selected wave parameters reflect very difficult operational conditions existing on the North Sea and the Baltic Sea. The analyzed variants of a case study ship represent the latest developments of modern hull forms. The concepts similar to V-shaped bulbous bow, X-bow, X-aft, B-bow...
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A large family of filled skutterudites stabilized by electron count
PublikacjaThe Zintl concept is important in solid-state chemistry to explain how some compounds that combine electropositive and main group elements can be stable at formulas that at their simplest level do not make any sense. The electronegative elements in such compounds form a polyatomic electron-accepting molecule inside the solid, a ‘polyanion’, that fills its available energy states with electrons from the electropositive elements...
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Improving performance of large thrust bearings through modeling and experimentation
PublikacjaLarge thrust bearings are highly loaded machine elements and their failures cause serious losses. Start ups and stoppages of the bearing under load are specially critical regimes of operation. Load carrying capacity depends on the profile of the oil gap. In transient states this profile is also changing. In the design of large thrust bearings minimizing thermo-elastic deformations is an important goal, which can be accomplished...
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The Influence of Laser Alloying of Ti13Nb13Zr on Surface Topography and Properties
PublikacjaThe laser alloying is a continually developing surface treatment because of its significant and specific structuration of a surface. In particular, it is applied for Ti alloys, being now the most essential biomaterials` group for load-bearing implants. The present research was performed on the Ti13Nb13Zr alloy subject to laser modification in order to determine the treatment effects on surface topography and its some mechanical...
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Pilot- scale plant for material recycling of whole waste tires
PublikacjaContinously growing demad for all kinds of vehicles and general tendency to regular exchange of tires are causing growth of scrap tires which need management. A risings of large quantities of used rubber products, especially used tires has been increasing every year in Poland, in 2006 it was 160 thousand. The waste management and recycling of used tires become a major environmental problem. It is worth noticing that tires which...