Filtry
wszystkich: 1565
wybranych: 1374
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: OFFSHORE STRUCTURES,DESIGN CALCULATIONS,SEA LOADING,STRESS EVALUATION,FEM
-
Sustainability of Civil Structures through the Application of Smart Materials: A Review
PublikacjaEvery year, structural flaws or breakdowns cause thousands of people to be harmed and cost billions of dollars owing to the limitations of design methods and materials to withstand extreme earthquakes. Since earthquakes have a significant effect on sustainability factors, there is a contradiction between these constraints and the growing need for more sustainable structures. There has been a significant attempt to circumvent...
-
Opracowanie procedury i badania wytrzymałościowe połączeń spawanych pomiędzy rurą kwadratowa a elementami giętymi na zimno ze stali S355 oraz testowanie połączeń o grubości 4, 6, 8mm typu S355
PublikacjaCelem pracy było: - opracowanie procedury badania wytrzymałości połączeń spawanych rozciąganych w kierunku prostopadłym i w kierunku równoległym (ścinanych) do osi spoiny. Spoiny te łączyły elementy rur kwadratowych o różnej grubości z elementami w kształcie ceownika giętymi na zimno. - wykonanie próbek do badań wytrzymałościowych wyciętych z elementów spawanych dostarczonych przez Zakład Produkcyjny firmy Borga obciążonych prostopadle...
-
Wpływ właściwości czynników chłodniczych na straty egzergii w pompie ciepła (Influence of Refrigerants Properties for Exergy Losses in Heat Pump)
PublikacjaArtykuł poświęcony jest wpływowi występujących w pompie ciepła strat egzergii na jej efektywność energetyczną, a co za tym idzie koszty funkcjonowania instalacji. Autorzy prezentują tu metodologię obliczeniową, która może być zastosowana w procesach projektowania układów cieplno-przepływowych. Obliczenia zostały wykonane na podstawie typowego układu powietrznej pompy ciepła pracującej w klimacie środkowo-europejskim. Ponadto w...
-
Investigations of Aerodynamics of Tesla Bladeless Microturbines
PublikacjaThe paper presents an analysis of a Tesla bladeless turbine for a co-generating micro-power plant of heat capacity 20 kW, whichoperates in an organic Rankine cycle with a low-boiling medium. Numerical calculations of flow in several Tesla turbine models areperformed for a range of design parameters. Results of investigations exhibit interesting features in the distribution of flowparameters within the turbine interdisk space. The...
-
Low-Cost Design Optimization of Microwave Passives Using Multi-Fidelity EM Simulations and Selective Broyden Updates
PublikacjaGeometry parameters of contemporary microwave passives have to be carefully tuned in the final stages of their design process to ensure the best possible performance. For reliability reasons, the tuning has to be to be carried out at the level of full-wave electromagnetic (EM) simulations. This is because traditional modeling methods are incapable of quantifying certain phenomena that may affect operation and performance of these...
-
Fluid structure interaction study of non-Newtonian Casson fluid in a bifurcated channel having stenosis with elastic walls
PublikacjaFluid–structure interaction (FSI) gained a huge attention of scientists and researchers due to its applications in biomedical and mechanical engineering. One of the most important applications of FSI is to study the elastic wall behavior of stenotic arteries. Blood is the suspension of various cells characterized by shear thinning, yield stress, and viscoelastic qualities that can be assessed by using non-Newtonian models. In this...
-
Validation of Hydraulic Mechanism during Blowout Trauma of Human Orbit Depending on the Method of Load Application
PublikacjaThe more we know about mechanisms of the human orbital blowout type of trauma, the better we will be able to prevent them in the future. As long as the buckling mechanism’s veracity is not in doubt, the hydraulic mechanism is not based on equally strong premises. To investigate the correctness of the hydraulic mechanism’s theory, two different methods of implementation of the hydraulic load to the finite element method (FEM) model...
-
NUMERICAL ESTIMATION OF HULL HYDRODYNAMIC DERIVATIVES IN SHIP MANOUVERING PREDICTION
PublikacjaOperating in crowded waterways pose a risk of accidents and disasters due to maneuvering limitations of the ship. In order to predict ship’s maneuvering characteristics at the design stage, model tests are often executed as the most accurate prediction tool. Two approaches can be distinguished here: free running model tests and numerical simulations based on planar motion model with the use of hydrodynamic derivatives obtained...
-
Application of Multivariate Analysis Methods in Welding Engineering
PublikacjaPhenomena and processes taking place during welding are usually very complex and, for this reason, should be described using multivariate methods. The article discusses the methodological basis and selected application areas as regards the solving of welding problems using statistical multivariate methods. In addition, the article presents exemplary applications of the design of experiment, multiple regression analysis, cluster...
-
Fatigue Performance of Double-Layered Asphalt Concrete Beams Reinforced with New Type of Geocomposites
PublikacjaThe reinforcement of asphalt layers with geosynthetics has been used for several decades, but proper evaluation of the influence of these materials on pavement fatigue life is still a challenging task. The presented study investigates a novel approach to the reinforcement of asphalt layers using a new type of geogrid composite, in which square or hexagonal polypropylene stiff monolithic paving grid with integral junctions is bonded...
-
Comparative Evaluation of Selected Biological Methods for the Removal of Hydrophilic and Hydrophobic Odorous VOCs from Air
PublikacjaDue to increasingly stringent legal regulations as well as increasing social awareness, the removal of odorous volatile organic compounds (VOCs) from air is gaining importance. This paper presents the strategy to compare selected biological methods intended for the removal of different air pollutants, especially of odorous character. Biofiltration, biotrickling filtration and bioscrubbing technologies are evaluated in terms of...
-
Planning, Configuration and Usefulness of Microseismic Monitoring on Eastern-Europe Platform – Example from East Pomerania
PublikacjaThe microseismic monitoring is a method of monitoring of fracture propagation during hydraulic fracturing process. The method uses array of geophones to localize micro tremors induced by liquid pumped underground at high rate and pressure. The acquired information helps to optimize fracturing process and prevents fracture growth to aquifer levels. It proved to be useful on several unconventional hydrocarbon reservoirs in the USA....
-
Influence of bush wear in water lubricated marine stern tube bearings with shaft misalignment
PublikacjaWater lubricated propeller shaft bearings are frequently employed on modern ships due to their advantages such as durability, simplicity and low price. Specific working conditions on ships cause shaft misalignment which often results in rapid wearing of bush and shaft. Shaft misalignment could be an effect of manufacturing or assembly faults but sometimes it appears due to hull or shaft deformation. The wearing process has influence...
-
Evaluation of Medical Staff Satisfaction for Workplace Architecture in Temporary COVID-19 Hospital: A Case Study in Gdańsk, Poland
PublikacjaThis article analyses the architecture that was used in the temporary AmberExpo hospital in Gdańsk, Poland which was installed during the COVID-19 pandemic. The construction of this type of facility is often based on experimental approaches, aimed at caring for patients suffering from an infectious disease in emergency conditions. In order to assess the level of employee satisfaction with the architectural and technical elements...
-
The application of environmental issues in designing urban structures – a framework for comprehensive local planning policies
PublikacjaThe implementation of environmental issues in planning and designing urban structures is becoming a novel approach and a common practice consistent with the paradigm of sustainable development. Maintaining environmental quality in urban areas, managing natural resources and understanding the complexity of urban systems is becoming increasingly challenging. Therefore, it is important to develop strategies for the integration of...
-
Multi-objective optimization of microwave couplers using corrected domain patching
PublikacjaPractical design of microwave components and circuits is a compromise between various, often conflicting objectives. In case of compact structures, the trade-offs are typically concerned with the circuit size and its electrical performance. Comprehensive information about the best possible trade-offs can be obtained by means of multi-objective optimization. In this paper, we propose a computationally efficient technique for identifying...
-
Low-Cost Multi-Objective Optimization of Antennas By Means Of Generalized Pareto Ranking Bisection Algorithm
PublikacjaThis paper introduces a generalized Pareto ranking bisection algorithm for low-cost multi-objective design optimization of antenna structures. The algorithm allows for identifying a set of Pareto optimal sets of parameters (that represent the best trade-offs between considered objectives) by iterative partitioning of the intervals connecting previously found designs and executing a Pareto-ranking-based poll search. The initial...
-
Enhanced uniform data sampling for constrained data‐driven modeling of antenna input characteristics
PublikacjaData-driven surrogates are the most popular replacement models utilized in many fields of engineering and science, including design of microwave and antenna structures. The primary practical issue is a curse of dimensionality which limits the number of independent parameters that can be accounted for in the modelling process. Recently, a performance-driven modelling technique has been proposed where the constrained domain of the...
-
FEM and experimental investigations of concrete temperature field in the massive stemwall of the bridge abutment
PublikacjaThe paper deals with the prediction of early-age concrete temperature of cast-in-place stemwall of the bridge abutment. The considered object is an arch bridge located in Gda´nsk. In the case of massive structures, it is particularly important to not exceed the temperature difference between the core and the concrete surface. Too high temperature gradient generates an increase in thermal stresses, what could be the reason of exceeding...
-
Verification of Selected Calculation Methods Regarding Shear Strength in Reinforced and Prestressed Concrete Beams
PublikacjaThe purpose of this article was an attempt to compare selected calculation methods regarding shear strength in reinforced and prestressed concrete beams. Several calculation methods were tested. This included codes: PN-EN 1992-1-1:2008 [1], ACI 318- 14 [2] and fib Model Code for Concrete Structures 2010 [3]. The analysis also consists of methods published in technical literature. Calculations of shear strengths were made based...
-
Theoretical Design of the Molecular Structure of Bent-Core Mesogens with Large Second-Order Nonlinear Optical Properties
PublikacjaABSTRACT: The first hyperpolarizability of two series of moleculeswith bent-shaped structures has been calculated at the ab initio level.The two series consist of carboxyl derivatives for which somemolecules are known to exhibit banana phases and of their sulfinatehomologues that have not been synthesized yet. The final purpose isto reveal the relevance or not in synthesizing these latter molecules.The strategy is based on reporting...
-
Self-Association of Amphotericin B: Spontaneous Formation of Molecular Structures Responsible for the Toxic Side Effects of the Antibiotic
PublikacjaAmphotericin B (AmB) is a lifesaving antibiotic used to treat deep-seated mycotic infections. Both the pharmaceutical activity and highly toxic side effects of the drug rely on its interaction with biomembranes, which is governed by the molecular organization of AmB. In the present work we present detailed analysis of self-assembly of AmB molecules in different environments, interesting from the physiological standpoint, based...
-
Copper(II) complexes of 7-amino-2-methylchromone and 7-aminoflavone: Magneto-structural, spectroscopic and DFT characterization
PublikacjaFour new complexes of copper(II) consisting of two different chromone derivatives with carbonyl and amine donor atoms: 7-aminoflavone (L1) and 7-amino-2-methylchromone (L2), were synthesized and characterized by X-ray diffraction, UV–Vis, FT-IR, EPR spectroscopy, MS and elemental analysis. In all four compounds, the chromone derivatives were found to act as monodentate O- or N-ligands. The structural characteristics of 1a and...
-
PV installations and the safety of residential buildings
PublikacjaThe dynamic development of the photovoltaic industry entails threats that have a direct impact on the safety of residential buildings. Appropriate design of a PV installation can be a challenge due to the multifaceted nature of this issue. The designer should take into account issues related to the selection of electrical parameters of the installation, adapting lightning and surge protection in accordance...
-
Comparative Analysis of Reactive Power Compensation Devices in a Real Electric Substation
PublikacjaA constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator...
-
Połączenie G3 dwóch kierunków prostych z użyciem krzywej NURBS
PublikacjaW artykule przedstawiono nową metodę projektowania układu geometrycznego toru kolejowego opartą na zastosowaniu krzywych NURBS (Non-Uniform Rational B-Spline) do opisu krzywizny. Punkty kontrolne krzywej NURBS wyznaczane są w procesie optymalizacji za pomocą algorytmu genetycznego. Jako kryterium optymalizacji przyjęto minimalizację oddziaływań dynamicznych występujących w układzie tor-pojazd przy spełnieniu warunków geometrycznych...
-
SOLUTIONS OF THE INTERMEDIATE SUPPORT STRUC- TURES OF THE NORTHERN MARMARA HIGHWAY (ISTAN- BUL’S RING ROAD) IN THE CONTEXT OF SEISMIC ACTIVITY
PublikacjaIn 2014–2018, as a result of the expansion of the city of Istanbul in Turkey, a project was imple- mented consisting of building a northern ring road, called the Northern Marmara Highway. The concept of the structural design of the ring road’s intermediate supports aims at constructing sup- ports that according to the TURKISH DLH 2008 standard must comply with the design require- ments for the three calculated earthquake insensitivity...
-
Rapid Antenna Optimization with Restricted Sensitivity Updates by Automated Dominant Direction Identification
PublikacjaMeticulous tuning of geometry parameters turns pivotal in improving performance of antenna systems. It is more and more often realized using formal optimization methods, which is demonstrably the most efficient way of handling multiple design variables, objectives, and constraints. Although in some cases a need for launching global search arises, a typical design scenario only requires local optimization, especially when a decent...
-
On Unsupervised Artificial-Intelligence-Assisted Design of Antennas for High-Performance Planar Devices
PublikacjaDesign of modern antenna structures is a challenging endeavor. It is laborious, and heavily reliant on engineering insight and experience, especially at the initial stages oriented towards the devel-opment of a suitable antenna architecture. Due to its interactive nature and hands-on procedures (mainly parametric studies) for validating suitability of particular geometric setups, typical antenna development requires many weeks...
-
Computationally efficient two-objective optimization of compact microwave couplers through corrected domain patching
PublikacjaFinding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective...
-
Evaluation of Vehicle Routing Problem Algorithms for Transport Logistics Using Dedicated GIS System
PublikacjaThe development and research related to optimization of fleet management is of high interest among many industrial and scientific entities related to logistics and transport. Optimal distribution of transportation resources leads to significant cost reduction. In this context, scientific research related to so called Vehicle Routing Problem (VRP) which relies on determining the shortest transport routes for a strictly limited number...
-
A comparison of structural and luminescence properties of lead(II) coordination polymers with isomeric thiophenecarboxylate ligands
PublikacjaTwo new lead(II) coordination polymers with isomeric thiophenecarboxylates, namely [Pb(2tpCOO)2]n (1) and [Pb(3tpCOO)2(H2O)]n (2) (2tpCOO− = thiophene-2-carboxylate, 3tpCOO− = thiophene-3-carboxylate), were synthesized and characterized. Single crystal X-ray crystallography revealed a distorted pentagonal pyramidal geometry {PbO6} around Pb in 1 and a distorted dodecahedral geometry {PbO8} in 2. The distortion derived from the...
-
Effect of osmolytes of different type on DNA behavior in aqueous solution. Experimental and theoretical studies
PublikacjaOsmolytes, the small organic molecules accumulated in cells under environmental stress, can modulate the stability of biopolymers such as proteins and DNA. In spite of many years of research, there is no established molecular mechanism of the influence of osmolytes on DNA structure. Here, we used two model osmolytes that denature (urea) or stabilize (trimethylglycine, TMG) proteins to study their effect on DNA in aqueous solutions...
-
Daylight Appraisal Classes For Achitecture Students A Survey Combined With A Practical Assessment For Educational Training Recommendations
PublikacjaThe main objectives of this article are: (i) to present the relations between architecture students' subjective assessment of daylight in classrooms and the objective evaluation of daylit conditions using daylight simulations tools, (ii) to formulate guidelines and recommendations on daylight appraisal methods and tools which may be useful in architectural training. The methodology used includes an evaluation of the results of...
-
A general theory for anisotropic Kirchhoff–Love shells with in-plane bending of embedded fibers
PublikacjaThis work presents a generalized Kirchhoff–Love shell theory that can explicitly capture fiber-induced anisotropy not only in stretching and out-of-plane bending, but also in in-plane bending. This setup is particularly suitable for heterogeneous and fibrous materials such as textiles, biomaterials, composites and pantographic structures. The presented theory is a direct extension of classical Kirchhoff–Love shell theory to incorporate...
-
PRESSURE DROP OF HFE7000 AND HFE7100 IN FLOW CONDENSATION IN MINICHANNELS WITH ACCOUNT OF NON-ADIABATIC EFFECTS
PublikacjaFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena involving the change of phase. There is a temptation to describe both these phenomena with one only correlation. From amongst the structures present in flow boiling and flow condensation at least the annular flow structure seems to be mostly appropriate to the common modeling. However, the shear stress acting between vapor phase and liquid...
-
Numerical crash analysis of the cable barrier
PublikacjaSafety barriers are used to increase road safety. Their basic task is to prevent the errant vehicle from getting off the road in places which are potentially dangerous for vehicle passengers. Barriers, which are used on European roads, must fulfill the requirements of EN 1317 standards by passing appropriate crash tests. Because of their high cost, numerical simulations are increasingly used to evaluate the properties of safety...
-
Dimensional Synthesis of Coupled-Resonator Pseudoelliptic Microwave Bandpass Filters with Constant and Dispersive Couplings
PublikacjaIn this paper, we propose a novel technique for the dimensional synthesis of coupled-resonator pseudoelliptic microwave filters with constant and dispersive couplings. The proposed technique is based on numerical simulations of small structures, involving up to two adjacent resonators, and it accounts for a loading effect from other resonators by replacing them with terminations coupled through appropriately scaled inverters. The...
-
Comparative analysis of thermodynamic cycles of selected nuclear ship power plants with high-temperature helium-cooled nuclear reactor
PublikacjaThis paper presents a comparative analysis of thermodynamic cycles of two ship power plant systems with a high-temperature helium- cooled nuclear reactor. The first of them is a gas system with recuperator , in which classical gas chamber is substituted for a HTGR reactor (High Temperature Gas-cooled Reactor) . The second of the considered cycles is a combined gas-steam system where working medium flux from gas turbine outlet...
-
High frequency impulse ground penetrating radar application in assessment of interlayer connections
PublikacjaGround Penetrating Radar (GPR) technique is commonly used in the nondestructive evaluation of pavement structures. In particular, this method is used to estimate thicknesses of pavement layers as well as it can be utilized in advanced studies of pavement structures. The device presented in this paper comprise the high frequency impulse antennas that allow for investigating the interlayer zones in terms of their electromagnetic...
-
Novel Low-Loss Substrates for 5G Applications
PublikacjaThis paper presents a feasibility study of a new type of microwave low-loss dielectric substrates for 5G network applications. The new substrate materials are composites of polypropylene and high-dielectric-constant micro-ceramics. This combination is expected to form a very low-loss dielectric material at low fabrication cost. Two substrate samples with different dielectric properties are fabricated and their characteristics at...
-
In silico design of telomerase inhibitors.
PublikacjaTelomerase is a reverse transcriptase enzyme involved in DNA synthesis at the end of linear chromosomes. Unlike in most other cells, telomerase is reactivated most cancerous cells and, therefore, has become a promising new anticancer target. Despite extensive research, direct telomerase inhibitors have yet not been introduced to the clinics because of the complexity of this enzyme. Structures of this protein from simple organisms...
-
Foundations of Grid Processing Architecture for the Comcute System
PublikacjaFundamental system algorithms and structures implemented in the Comcute system are described and analysed in detail. Layered architecture of the system model is highlighted. System tasks of the layers are elaborated, presented and described. Operational details of communication interfaces among layers are worked out and examined. The focus is put onto implemented system components with regard to their operability and efficiency....
-
Calix[4]arene-Thioamides as Ionophores for Transition and Heavy Metal cations
PublikacjaCalix[4]arene derivatives play an important role as sensing materials in Ion Selective Electrodes(ISEs). Nowadays a high impact is put to control in natural waters the level of toxic heavy metals, like Pb ,Cd, Hg or Cu which may cause the great risk to human health. Our goal was to design and to synthesize ligands possessing ability to bind transition and heavy metal cations. The synthesis, crystal structures,extractive and ionophoric...
-
Low-cost multi-objective optimization of antennas using Pareto front exploration and response features
PublikacjaIn the paper, a procedure for low-cost multi-objective optimization of antenna structures is presented. Our approach is based on exploration of the Pareto front representing the best possible trade-offs between conflicting objectives, here, the structure size and its electrical performance. Starting from the design representing the best in-band reflection level, subsequent Pareto-optimal designs are identified through local constrained...
-
Chemical Theory of Machines, basic principles of strength with examples of calculations
PublikacjaThis book encompasses the essential range of information on technical aspects of mechanical design. It was written primarily for the students and staff of chemistry faculties of technical universities, yet it may also be utilized by everyone, who ether would like to try or already enjoys designing, but cannot take advantage of typical stress & machine construction handbooks. These handbooks often require familiarity with the concepts...
-
Pre-swirl energy saving device in marine application
PublikacjaThis paper covers topics of energy saving device (ESD) with application to marine propulsors. The form of ESD, considered in this paper, consists of fixed lifting foils mounted in front of the screw propeller (the pre-swirl stator/guide vanes). An algorithm for designing propulsion systems, consisting of guide vanes and screw propeller, is presented. The proposed method relies on hybrid lifting line (guide vanes)-lifting surface...
-
Refinement of the Hardening Soil model within the small strain range
PublikacjaThe popularity of the elasto-plastic Hardening Soil (HS) model is based on simple parameter identification from standard testing and empirical formulas. The HS model is implemented in many commercial FE codes designed to analyse geotechnical problems. In its basic version, the stress–strain behaviour within the elastic range is subject to the hypoelastic power law, which assures the barotropy of the elastic stiffness. However,...
-
Influence of grain shape on the mechanical behaviour of granular materials
PublikacjaWe performed series of numerical vertical compression tests on assemblies of 2D granular material using a Discrete Element code and studied the results in regard to the grain shape. The samples consist of 5000 grains made either of 3 overlapping discs (clump - grain with concavities) or of six-edged polygons (convex grain). These two types of grains have a similar external envelope, ruled with a geometrical parameter α. In the...
-
A geophysical, geochemical and microbiological study of a newly discovered pockmark with active gas seepage and submarine groundwater discharge (MET1-BH, central Gulf of Gdańsk, southern Baltic Sea)
PublikacjaHigh-resolution bathymetric data were collected with a multi-beam echosounder in the southern part of the Baltic Sea (region MET1, Gulf of Gdańsk) revealing the presence of a 10 m deep and 50 m in diameter pockmark (MET1-BH) on the sea bottom (78.7 m). To date, no such structures have been observed to reach this size in the Baltic Sea. The salinity of the near-bottom water in the pockmark was about 2 PSU (about 31.22 mmol/l...