Filtry
wszystkich: 935
wybranych: 905
Wyniki wyszukiwania dla: NON-LINEAR STATIC ANALYSES
-
Possible quadrupole-order-driven commensurate-incommensurate phase transition in B20 CoGe
PublikacjaThe B20-type cobalt germanide CoGe was investigated by measuring the specific heat, resistivity, and 59Co nuclear magnetic resonance (NMR).We observed a phase transition at TQ = 13.7 K, evidenced by a very narrow peak of the specific heat and sharp changes of the nuclear spin-spin (T −1 2 ) and spin-lattice (T −1 1 ) relaxation rates. The fact that the entropy release is extremely small and the Knight shift is almost independent...
-
Selected Aspects of 3D Printing for Emergency Replacement of Structural Elements
PublikacjaThe paper presents a synthetic characterization of modern methods of manufacturing or regenerating machine elements. Considered methods are machining and additive methods, in particular 3D printing in the FDM/FFF technique. For the study, the authors made samples of the holder bracket using selected methods. Samples made by machining operations, 3D printing with various filling were tested. The paper contains a technical and economic...
-
ENERGY ANALYSIS OF PROPULSION SHAFT FATIGUE PROCESS IN ROTATING MECHANICAL SYSTEM PART I TESTING SIGNIFICANCE OF INFLUENCE OF SHAFT MATERIAL FATIGUE EXCITATION PARAMETERS
PublikacjaThe article discusses the problem of mathematical modelling of energy conversion processes in a rotating mechanical system for the purpose of identifying fatigue states of propulsion shafts in this system. A simplified physical model of the analysed system, constructed in an appropriate scale, has made the basis for the experimental research. The research programme took into consideration mechanical fatigue excitation of the model...
-
Decision support system for design of long distance heat transportation system
PublikacjaDistrict Heating (DH) systems are commonly supplied using local heat sources. Nowadays, modern insulation materials allow for effective and economically viable heat transportation over long distances (over 20 km). The paper proposes a Decision Support System (DSS) for optimized selection of design and operating parameters of a long distance Heat Transportation System (HTS). The method allows for evaluation of feasibility and effectiveness...
-
Radio Channel Measurements in Off-Body Communications in a Ferry Passenger Cabin
PublikacjaThis paper presents an off-body radio channel measurements in a ferry passenger cabin at 2.45 GHz band, for static sleeping scenarios with different body orientation and on-body antennas placements, and also for upper and lower sleeping berths. The measurements have been performed with two types of on-body wearable receiving antennas: FlexPIFA (flexible planar inverted F antenna), and FlexNotch (flexible adhesive-backed notch antenna)...
-
A New Rehabilitation Device for Balance Impaired Individuals
PublikacjaIn the paper authors present a device designed to improve the rehabilitation process of people with balance impairment. The discussed device (JStep) utilizes a commercially available static standing frame (stander) modified in order to fit force sensing units under the feet and in the pillows around the hips of a patient. While executing rehabilitation tasks, the patient may compensate his balance deficiency by leaning on the pillows...
-
INFOGEST static in vitro simulation of gastrointestinal food digestion
PublikacjaDeveloping a mechanistic understanding of the impact of food structure and composition on human health has increasingly involved simulating digestion in the upper gastrointestinal tract. These simulations have used a wide range of different conditions that often have very little physiological relevance, and this impedes the meaningful comparison of results. The standardized protocol presented here is based on an international consensus...
-
Sensorless field oriented control for five-phase induction motors with third harmonic injection and fault insensitive feature
PublikacjaThe paper presents a solution for sensorless field oriented control (FOC) system for five-phase induction motors with improved rotor flux pattern. In order to obtain the advantages of a third harmonic injection with a quasi-trapezoidal flux shape, two vector models, α1–β1 and α3–β3, were transformed into d1– q1, d3– q3 rotating frames, which correlate to the 1st and 3rd harmonic plane respectively. A linearization approach of the...
-
The early failure of the gamma nail and the dynamic hip screw in femurs with a wide medullary canal. A biomechanical study of intertrochanteric fractures
PublikacjaBackground: Intertrochanteric fractures may occur in a bone with a wide medullary canal that may lead to significant mobility of a intramedullary nail, contrary to an extramedullary device. This study evaluates the Dynamic Hip Screw and the gamma nail in AO 31.A2.1 fractures in these circumstances. Methods: Synthetic femora with canals drilled to 18 mm were used. Five fixation types were examined: a 2 - hole and a 4 – hole Dynamic...
-
Investigation into the Effect of Spinel Pigments on the Photostability and Combustion Properties of Ethylene-Norbornene Copolymer
PublikacjaMulticolor ethylene-norbornene (EN) composites filled with three different spinel pigments (Cobalt Green-PG50, Zinc Iron Yellow-PY 119, Praseodym Yellow-PY159) were prepared by melt mixing and characterized in terms of their stability under destructive environmental conditions. The EN films were subjected to accelerated aging by ultraviolet (UV) photooxidation for 300 h, 600 h, or 900 h. The mechanical performance of the EN composites...
-
Adaptive Positioning Systems Based on Multiple Wireless Interfaces for Industrial IoT in Harsh Manufacturing Environments
PublikacjaAs the industrial sector is becoming ever more flexible in order to improve productivity, legacy interfaces for industrial applications must evolve to enhance efficiency and must adapt to achieve higher elasticity and reliability in harsh manufacturing environments. The localization of machines, sensors and workers inside the industrial premises is one of such interfaces used by many applications. Current localization-based systems...
-
Modelling and Measurement of Folk Guitar: Truss Rod and Strings in Numerical Analysis of Tone
PublikacjaThe study makes an attempt to model a complete vibrating guitar including its non-linear features, specifically the tension-compression of truss rod and tension of strings. The purpose of such a model is to examine the influence of design parameters on tone. Most experimental studies are flawed by uncertainties introduced by materials and assembly of an instrument. Since numerical modelling of instruments allows for deterministic...
-
Buckling of simplified models of silo with corrugated walls and vertical stiffeners
PublikacjaThe paper deals with buckling of cylindrical silos composed of corrugated sheets and vertical stiffeners (columns). Comprehensive finite element analyses were carried out for a perfect silo by means of a linear buckling approach. Corrugated walls were simulated as an equivalent orthotropic shell and vertical thin-walled columns as beam elements. Calculations for perfect silos with different numbers of columns made it possible to...
-
Non linear identification of underwater vehicles. W: [CD-ROM] Conference Proceedings. The 29th Israel Conference on Mechanical Engineering. May 12-13, 2003 Haifa, Israel. Haifa: Technion - Israel Inst. Technol.**2003[B8] s. 1-8, 5 rys. bibliogr. 7 poz. Nieliniowa identyfikacja pojazdów podwodnych.
PublikacjaArtykuł dotyczy identyfikacji nieliniowych modeli pojazdów podwodnych o wie-lu zmiennych. Zaproponowana metoda działa w obszarze czasu rzeczywistego imoże być stosowana do nieliniowych modeli, które są liniowe w części doty-czącej nieznanego wektora parametrów. W celu poradzenia sobie z parametramizmieniającymi się w czasie, zastosowano rekursyjną wersję algorytmu identy-fikacji. Po krótkim opisie matematycznych podstaw...
-
Two-phase optimizing approach to design assessments of long distance heat transportation for CHP systems
PublikacjaCogeneration or Combined Heat and Power (CHP) for power plants is a method of putting to use waste heat which would be otherwise released to the environment. This allows the increase in thermodynamic efficiency of the plant and can be a source of environmental friendly heat for District Heating (DH). In the paper CHP for Nuclear Power Plant (NPP) is analyzed with the focus on heat transportation. A method for effectivity and feasibility...
-
Processing and structure–property relationships of natural rubber/wheat bran biocomposites
PublikacjaIn this work, wheat bran was used as cellulosic filler in biocomposites based on natural rubber. The impact of wheat bran content [ranging from 10 to 50 parts per hundred rubber (phr)] on processing, structure, dynamic mechanical properties, thermal properties, physico-mechanical properties and morphology of resulting biocomposites was investigated. For better characterization of interfacial interactions between natural rubber...
-
Processing, mechanical and thermal behavior assessments of polycaprolactone/agricultural wastes biocomposites
PublikacjaIn this paper, brewer’s spent grain (BSG) was applied as potential lignocellulose biofiller in biocompos-ites based on polycaprolactone (PCL). The PCL/BSG biocomposites filled with varying content of biofillerswere prepared via low-temperature melt-compounding. These conditions allow limiting thermal degra-dation of used biofillers during processing. The influence of biofiller content (ranging from 25 to 200parts by weight on 100...
-
The influence of crude glycerol and castor oil-based polyol on the structure and performance of rigid polyurethane-polyisocyanurate foams
PublikacjaIn this work, biopolyol obtained from two types of industrial crops’ processing products: crude glycerol and castor oil was used for preparation or rigid polyurethane-polyisocyanurate foams. Bio-based polyol was obtained via crude glycerol polymerization and further condensation of resulting polyglycerol with castor oil. Rigid polyurethane-polyisocyanurate foams were prepared at partial substitution (0–70 wt.%) of petrochemical...
-
Waste tire rubber devulcanization technologies: State-of-the-art, limitations and future perspectives
PublikacjaWaste tires management is a serious and global environmental problem. Therefore, searching for low-cost and industrial-scale applicable tire recycling methods is gaining more and more attention. Waste tire rubber is valuable source of secondary raw materials for the circular economy and current trends indicate that application of waste rubbers during manufacturing value-added products should increase in near future. Sustainable...
-
Management of ground tire rubber waste by incorporation into polyurethane-based composite foams
PublikacjaRapid economic growth implicated the developing multiple industry sectors, including the automotive branch, increasing waste generation since recycling and utilization methods have not been established simultaneously. A very severe threat is the generation of enormous amounts of post-consumer tires considered burdensome waste, e.g., due to the substantial emissions of volatile organic compounds (VOCs). Therefore, it is essential...
-
Nonlinear Free and Forced Vibrations of a Hyperelastic Micro/Nanobeam Considering Strain Stiffening Effect
PublikacjaIn recent years, the static and dynamic response of micro/nanobeams made of hyperelasticity materials received great attention. In the majority of studies in this area, the strain-stiffing effect that plays a major role in many hyperelastic materials has not been investigated deeply. Moreover, the influence of the size effect and large rotation for such a beam that is important for the large deformation was not addressed. This...
-
Influence of windsurfing fin stiffness distribution on the lift-drag characteristics
PublikacjaThis article addresses the problem of determining the hydromechanical loads generated by flexible hydrofoils. The research was done on the example of the composite windsurfing fin for the RS:X monotype class. Despite the assumption of fins identity, everyday practice showed that variations of mechanical properties occur and strongly affect their performance. Therefore, we decided to study the differences between the windsurfing...
-
Static magnetic multipole susceptibilities of the relativistic hydrogenlike atom in the ground state: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function
PublikacjaWe study far- and near-field magnetic and electric multipole moments induced in the ground state of the Dirac one-electron atom placed in a weak 2L-pole magnetostatic field. The analysis is carried out within the framework of the first-order Rayleigh-Schrödinger perturbation theory, with the use of the Sturmian expansion of the generalized Dirac-Coulomb Green function [Szmytkowski, J. Phys. B 30, 825 (1997);J. Phys. B 30, 2747(E)...
-
Analysis of the possibilities in railways shape assessing using GNSS mobile measurements
PublikacjaIn recent years, a dynamic development of satellite positioning techniques using both static and mobile GNSS coordinates register mode can be observed. In addition, still developing Real-time GNSS Networks, post-processing algorithms and another measurement signal analysis algorithms, make the satellite measurements increasingly used in railway industry sector. In the article the possibilities which follows from the mobile satellite...
-
Force transfer and stress distribution in short cantilever deep beams loaded throughout the depth with a various reinforcement
PublikacjaDeep beams used as the main reinforced concrete structural elements which taking over the load and stiffening construction are often found in high-rise buildings. The architecture of these buildings is sometimes sophisticated and varied, arouse the admiration of the majority of recipients, and thus causing an engineering challenge to correctly design the structural system and force transfer. In such structures is important to shape...
-
Assessment of Failure Occurrence Rate for Concrete Machine Foundations Used in Gas and Oil Industry by Machine Learning
PublikacjaConcrete machine foundations are structures that transfer loads from machines in operation to the ground. The design of such foundations requires a careful analysis of the static and dynamic effects caused by machine exploitation. There are also other substantial differences between ordinary concrete foundations and machine foundations, of which the main one is that machine foundations are separated from the building structure....
-
Performance Analysis of Machine Learning Methods with Class Imbalance Problem in Android Malware Detection
PublikacjaDue to the exponential rise of mobile technology, a slew of new mobile security concerns has surfaced recently. To address the hazards connected with malware, many approaches have been developed. Signature-based detection is the most widely used approach for detecting Android malware. This approach has the disadvantage of being unable to identify unknown malware. As a result of this issue, machine learning (ML) for detecting malware...
-
Comprehensive Enhancement of Prepolymer-Based Flexible Polyurethane Foams’ Performance by Introduction of Cost-Effective Waste-Based Ground Tire Rubber Particles
PublikacjaMaterial innovations in polyurethane (PU) foams should ideally combine performance enhancement, environmental impact limitation, and cost reduction. These goals can be achieved by applying recycled or waste-based materials without broader industrial applications, implicating their low price. Herein, from 5 to 20 parts by weight of ground tire rubber (GTR) particles originated from the recycling of postconsumer car tires were incorporated...
-
Comprehensive Investigation of Stoichiometry–Structure–Performance Relationships in Flexible Polyurethane Foams
PublikacjaPolyurethane (PU) foams are versatile materials with a broad application range. Their performance is driven by the stoichiometry of polymerization reaction, which has been investigated in several works. However, the analysis was often limited only to selected properties and compared samples differing in apparent density, significantly influencing their performance. In the bigger picture, there is still a lack of comprehensive studies...
-
Mathematical approach to design 3D scaffolds for the 3D printable bone implant
PublikacjaThis work demonstrates that an artificial scaffold structure can be designed to exhibit mechanical properties close to the ones of real bone tissue, thus highly reducing the stress-shielding phenomenon. In this study the scan of lumbar vertebra fragment was reproduced to create a numerical 3D model (this model was called the reference bone sample). New nine 3D scaffold samples were designed and their numerical models were created....
-
The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites
PublikacjaIn this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency...
-
Static electric and magnetic multipole susceptibilities for Dirac one-electron atoms in the ground state
PublikacjaWe present tabulated data for several families of static electric and magnetic multipole susceptibilities for hydrogenic atoms with nuclear charge numbers from the range $1\leq Z\leq137$. Atomic nuclei are assumed to be point-like and spinless. The susceptibilities considered include the multipole electric polarizabilities $\alpha_{\mathrm{E}L\to\mathrm{E}L}$ and magnetizabilities (magnetic susceptibilities) $\chi_{\mathrm{M}L\to\mathrm{M}L}$...
-
Meso‐scale analyses of size effect in brittle materials using DEM
PublikacjaThe paper describes numerical meso-scale results of a size effect on strength, brittleness and fracture in brittle materials like concrete. The discrete element method (DEM) was used to simulate the size effect during quasi-static splitting tension with the experimental-based meso-structure. The two-dimensional (2D) calculations were carried out on concrete cylindrical specimens with two diameters wherein two different failure...
-
Application of linear buckling sensitivity analysis to economic design of cylindrical steel silos composed of corrugated sheets and columns
PublikacjaThe paper deals with global stability of steel cylindrical silos composed of corrugated walls and vertical columns with loads imposed by a bulk solid following Eurocode 1. The optimum silo design with respect to the steel weight was based on a sensitivity analysis method. The changes of silo column profiles at each design step were performed by means of influence lines for the buckling load factor due to the unit column bending...
-
Simplified stability analysis of steel cylindrical silos with corrugated walls and vertical columns
PublikacjaIn the paper a simplified stability analysis of steel cylindrical silos composed of corru¬gated walls and vertical open-sectional columns was proposed. The whole 3D silo was modeled as a single column resting on elastic foundation provided by the silo walls. In proposed formula for the calculation of the foundation stiffness the curvature of the silo walls was taken into account. Three different analyses were carried out using...
-
Long range molecular dynamics study of regulation of eukaryotic glucosamine-6-phosphate synthase activity by UDP-GlcNAc
PublikacjaGlucosamine-6-phosphate (GlcN-6-P) synthase catalyses the first and practically irreversible step in hexosamine metabolism. The final product of this pathway, uridine 5' diphospho N-acetyl-D-glucosamine (UDPGlcNAc), is an essential substrate for assembly of bacterialand fungal cell walls. Moreover, the enzyme is involved in phenomenon of hexosamine induced insulin resistance in type II diabetes, which makes it a potential target...
-
The impact of filler thermomechanical modifications on static and dynamic mechanical performance of flexible foamed polyurethane/ground tire rubber/zinc borate composites
PublikacjaThe rapid development of the automotive industry is very beneficial to many aspects of human life, but it is also a very significant environmental burden. The most straightforward impact is related to the generation of exhaust, but the management of post-consumer car parts is also a major challenge. Among them, waste tires are very burdensome due to their enormous numbers. Therefore, it is essential to develop novel, environmentally...
-
Load effect impact on the exploitation of concrete machine foundations used in the gas and oil industry
PublikacjaMachine foundations is a critical topic in the gas and oil industry, which design and exploitation require extensive technical knowledge. Machine foundations are the constructions which are intended for mounting on it a specific type of machine. The foundation has to transfer dynamic and static load from machine to the ground. The primary difference between machine foundations and building foundations is that the machine foundations...
-
Designing digital displays and interactive media in today’s cities by night. Do we know enough about attracting attention to do so?
PublikacjaWith the huge transformation in the development of digital screen technology and its consistently decreasing cost, digital billboards are progressively replacing traditional static, two-dimensional poster advertisements in our cities1. Previously, due to the substantial expenditure involved, they were only available to major international brands with vast promotional resources to build their brand fame. Today, however, they are...
-
Empirical Analysis of Forest Penalizing Attribute and Its Enhanced Variations for Android Malware Detection
PublikacjaAs a result of the rapid advancement of mobile and internet technology, a plethora of new mobile security risks has recently emerged. Many techniques have been developed to address the risks associated with Android malware. The most extensively used method for identifying Android malware is signature-based detection. The drawback of this method, however, is that it is unable to detect unknown malware. As a consequence of this problem,...
-
Finite elements based on a first-order shear deformation moderate rotation shell theory with applications to the analysis of composite structures
Publikacja -
Modeling of textural anisotropy in granular materials with micro-polar hypoplasticity
PublikacjaW artykule przedstawiono wyniki numerycznej wpływu anizotropii strukturalnej w materiałach granulowanych na powstawanie lokalizacji odkształceń. Obliczenia wykonano dla ściskania w płaskim stanie odkształcenia stosując metodę elementów skończonych na bazie mikropolarnego prawa hipoplastycznego. Wpływ anizotropii modelowano stosując skorelowane pola początkowego wskaźnika porowatości.
-
Shell with random geometric imperfections simulation-based approach
PublikacjaPrzedstawiono analizę powłok z losowymi imperfekcjami. Zastosowano nieliniowe geometrycznie i materiałowo modele. Geometryczne imperfekcje opisano za pomocą pojedynczych zmiennych oraz pól losowych. Wykorzystano metodę Monte Carlo i metodę elementów skończonych. Zbadano wpływ różnych rozkładów prawdopodobieństwa imperfekcji geometrycznych na probabilistyczny rozkład nośności granicznej powłok. Zastosowane rozkłady ekstremalne imperfekcji...
-
Large rotations in first-order shear deformation FE analysis of laminated shells
PublikacjaAbstrakt: Teoria powłok o skończonych obrotach w ramach modelu ścinania pierwszego rzędu stanowi podstawę zaprezentowanego w pracy algorytmu MES statycznej, geometrycznie nieliniowej analizy konstrukcji warstwowych. Szczególną uwagę zwrócono na właściwy opis skończonych obrotów przy zastosowaniu kątów Eulera oraz procedurę uaktualniania parametrów obrotowych. Przedstawiono sformułowanie przyrostowe w stacjonarnym opisie Lagrange´a....
-
Effect of lag screw on stability of first metatarsophalangeal joint arthrodesis with medial plate
PublikacjaBackground: First metatarsophalangeal joint (MTP-1) arthrodesis is a commonly performed procedure in the treatment of disorders of the great toe. Since the incidence of revision after MTP-1 joint arthrodesis is not insignificant, a medial approach with a medially positioned locking plate has been proposed as a new technique. The aim of the study was to investigate the effect of the application of a lag screw on the stability and...
-
Stability Enhancement of Grid-Connected Wind Power Generation System Using PSS, SFCL and STATCOM
PublikacjaThe stability related issues may occur in a power system due to disturbances in generating or loading conditions, especially in the presence of distributed generation (DG) based on renewable energy resources (RERs). This paper proposes a novel strategy for the stability enhancement of a wind power generation system (WPGS) by using a combination of three devices, namely, a power system stabilizer (PSS), resistive superconductor...
-
High Frequency Conducted Emission in AC Motor Drives Fed By Frequency Converters: Sources and Propagation Paths
PublikacjaProvides a concise and thorough reference for designing electrical and electronic systems that employ adjustable speed drives Electrical and electronic systems that employ adjustable speed drives are being increasingly used in present-day automation applications. They are considered by many application engineers as one of the most interfering components, especially in a contemporarily faced industrial environment. This book fills...
-
Consideration of dynamic loads in the determination of axle load spectra for pavement design
PublikacjaAxle load spectra constitute a crucial part of the data for pavement design and pavement distress analysis. Typically, axle load spectra represent static load from vehicles and do not include dynamic loads generated by vehicles in motion. While dynamic loads can significantly contribute to faster pavement distress, this fact is mostly omitted in pavement design methods. The paper presents a methodology for consideration of dynamic...
-
Effect of Base-Connection Strength and Ductility on the Seismic Performance of Steel Moment-Resisting Frames
PublikacjaColumn-base connections in steel moment-resisting frames (SMFs) in seismic regions are commonly designed to develop the capacity of adjoining column with an intent to develop a plastic hinge in the column member, rather than in the connection (i.e., a strong-base design). Recent research has shown base connections to possess high ductility, indicating that this practice may be not only expensive but also unnecessary. This suggests...
-
Damage-involved response of two colliding buildings under non-uniform earthquake loading
PublikacjaPounding between insufficiently separated buildings, which may result in considerable damage or may even lead to the total collapse of colliding structures, has been repeatedly observed during earthquakes. Earthquake-induced collisions of buildings has been intensively studied applying various structural models. It was assumed in the analyses, however, that the seismic excitation is identical for all structural supports; whereas,...