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Sequence-dependent structural properties of B-DNA: what have we learned in 40 years?
PublicationThe structure of B-DNA, the physiological form of the DNA molecule, has been a central topic in biology, chemistry and physics. Far from uniform and rigid, the double helix was revealed as a flexible and structurally polymorphic molecule. Conformational changes that lead to local and global changes in the helix geometry are mediated by a complex choreography of base and backbone rearrangements affecting the ability of the B-DNA...
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Verification of punching shear outside the shear cap by the direct method
PublicationThe proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear...
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Experimental tests of lintel hybrid beams
PublicationThe results of experimental tests of lintel hybrid beams made of air concrete and prestressed concrete were presented in paper. Blocks of air concrete was a protective element for the construction one. The length of hybrid beams was 3.0 m, while total height 27 cm. It was assumed that hybrid beams will work in the simply-supported scheme (with a 10 cm support) loaded uniformly over the entire length. The object of the tests were...
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Experimental study on single phase operation of microjet augmented heat exchanger with enhanced heat transfer surface
PublicationThe article presents experimental investigations on a prototype heat exchanger. Presented research is focused on combined active and passive enhancement techniques of surface modification and microjet impingement. The results were compared to reference plate heat exchanger without microjet impingement. The Wilson plot method was applied to determine the heat transfer coefficients in the single phase operation. The heat exchanger...
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Randomly Functionalized Polyethylenes: In Quest of Avoiding Catalyst Deactivation
PublicationWell-defined randomly functionalized polyolefins produced by catalysis form an interesting class of polymers with great potential for various applications. One of the major challenges for the production of these materials forms the incompatibility of the commonly used electrophilic group 4 metal based catalysts and the desired nucleophilic, especially protic functionalities like hydroxyl and carboxylic acid groups. Although pacification...
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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublicationA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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A coarse‐grained approach to NMR ‐data‐assisted modeling of protein structures
PublicationThe ESCASA algorithm for analytical estimation of proton positions from coarse-grained geometry developed in our recent work has been implemented in modeling protein structures with the highly coarse-grained UNRES model of polypeptide chains (two sites per residue) and nuclear magnetic resonance (NMR) data. A penalty function with the shape of intersecting gorges was applied to treat ambiguous distance restraints, which automatically...
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Fast surrogate-assisted frequency scaling of planar antennas with circular polarisation
PublicationIn this work, the problem of computationally efficient frequency scaling (re-design) of circular polarisation antennas is addressed using surrogate-assisted techniques. The task is challenging and requires the identification of the optimum geometry parameters to enable the operation of the re-designed structure at a selected (required) centre frequency. This involves handling several performance figures such as the antenna gain,...
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Simulations of hydro-fracking in rock mass at meso-scale using fully coupled DEM/CFD approach
PublicationThe paper deals with two-dimensional (2D) numerical modelling of hydro-fracking (hydraulic fracturing) in rocks at the meso-scale. A numerical model was developed to characterize the properties of fluid-driven fractures in rocks by combining the discrete element method (DEM) with computational fluid dynamics (CFD). The mechanical behaviour of the rock matrix was simulated with DEM and the behaviour of the fracturing fluid flow...
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Structural properties of hydration shell around various conformations of simple polypeptides
PublicationIn this paper we investigate structural properties of water within the solvation shell around the peptide core created by a well-defined conformation of polypeptide chain. The following secondary structures are investigated: linear (straight chain), and three helices PII (polyproline-like), 310, and α. We propose using the two-particle contribution to entropy as a rational measure of the water structural ordering within the solvation...
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Non-Newtonian Mathematics Instead of Non-Newtonian Physics: Dark Matter and Dark Energy from a Mismatch of Arithmetics
PublicationNewtonian physics is based on Newtonian calculus applied to Newtonian dynamics. New paradigms such as ‘modified Newtonian dynamics’ (MOND) change the dynamics, but do not alter the calculus. However, calculus is dependent on arithmetic, that is the ways we add and multiply numbers. For example, in special relativity we add and subtract velocities by means of addition β1⊕β2=tanh(tanh−1(β1)+tanh−1(β2)), although multiplication β1⊙β2=tanh(tanh−1(β1)⋅tanh−1(β2)),...
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Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands
PublicationCoordination complexes that possess large magnetic anisotropy (otherwise known as zero-field splitting, ZFS) have possible applications in the field of magnetic materials, including single molecule magnets (SMMs). Previous studies have explored the role of coordination number and geometry in controlling the magnetic anisotropy and SMM behavior of high-spin (S = 3/2) Co(II) complexes. Building upon these efforts, the present work...
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Heat Transfer of the Multicolor-Laser-Sources-Irradiated Nanoparticles in Reference to Thermal Processes
PublicationUnlike the standard materials, metallic nanoparticles offer enhancing the heat convertion rate which implies the maximum and average temperature boost significantly in the considered system. The work’s purpose is to examine heat transfer in the metallic nanoparticles which have been deposited on a glassy substrate, enabling the nanostructures thermoablation. Furthermore, the functionalized substrate is irradiated with multicolor-laser-sources,...
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Example of Using Particle Swarm Optimization Algorithm with Nelder–Mead Method for Flow Improvement in Axial Last Stage of Gas–Steam Turbine
PublicationThis article focuses principally on the comparison baseline and the optimized flow efficiency of the final stage of an axial turbine operating on a gas–steam mixture by applying a hybrid Nelder– Mead and the particle swarm optimization method. Optimization algorithms are combined with CFD calculations to determine the flowpaths and thermodynamic parameters. The working fluid in this study is a mixture of steam and gas produced...
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Influence of meniscus shape in the cross sectional plane on the knee contact mechanics
PublicationWe present a three dimensional finite element analysis of stress distribution and menisci deformation in the human knee joint. The study is based on the Open Knee model with the geometry of the lateral meniscus which shows some degenerative disorders. The nonlinear analysis of the knee joint under compressive axial load is performed. We present results for intact knee, knee with partial and complete radial posterior meniscus root...
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Objective selection of minimum acceptable mesh refinement for EMC simulations
PublicationOptimization of computational electromagnetics (CEM) simulation models can be costly in both time and computing resources. Mesh refinement is a key parameter in determining the number of unknowns to be processed. In turn, this controls the time and memory required for a simulation. Hence, it is important to use only a mesh that is good enough for the objectives of the simulation, whether for direct handling of high-fidelity EM...
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Problems with modelling the strength properties of sailing vessels rigging ropes
PublicationThis article presents the basic parameters of soft ropes: natural fibre ropes, soft wire ropes and synthetic fibre ropes used for running rigging. There are only several materials still used for the production of natural fibre ropes, including cotton, jute, hemp, sisal and manila hemp. The most commonly used soft wire ropes are twisted pair ropes; for smaller diameters there is a 6x19M - FC rope and for larger diameters – 6x37M...
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Low-cost and reliable geometry scaling of compact microstrip couplers with respect to operating frequency, power split ratio, and dielectric substrate parameters
PublicationA technique for rapid re-design of miniaturised microstrip couplers with respect to operating conditions as well as material parameters of the dielectric substrate is proposed. The dimension scaling process is based on a set of pre-optimised reference designs, obtained for an equivalent circuit model of the coupler at hand. The reference designs are utilised to construct an inverse surrogate model which – upon suitable correction...
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NUMERICAL SIMULATIONS OF HONING PROCESS OF THIN WALL CYLINDER LINERS, WITH CONSTANT AND WITH VARIABLE THICKNESS OF WALL OF HONED PARTS
PublicationNumerical simulations of honing process of thin-wall cylinder liners, with constant and with variable thickness of the wall of honed workpieces can improve and can help to conduct the experimental research of honing process and can improve the honing process. A very valuable research assumption, before performing the numerical analysis of computer simulation of honing process, is the measurement of the real geometry of the honing...
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Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants
PublicationSurface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb- 13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of...
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Determination of Mechanical Energy Loss in Steady Flow by Means of Dissipation Power
PublicationWhen systems of simple geometry like pipes or regular channels are considered, the mechan- ical energy loss of the fluid flow can be expressed by local and longitudinal empirical energy loss coefficients. However, in the case of large spatially distributed objects, there are no simple approaches to this task. In practice, general recommendations addressing different types of objects are used, but they usually provide very coarse...
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Performance-Driven Inverse/Forward Modeling of Antennas in Variable-Thickness Domains
PublicationDesign of contemporary antenna systems is a challenging endeavor. The difficulties are partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities, but also constraints imposed upon the physical size of the radiators. Furthermore, conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise dictated by reliability,...
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The Motion Analysis of Attacus Atlas Rigid Wing
PublicationThe remarkable aerodynamic efficiency of flapping insect wings has fascinated researchers for many years. Butterfly wings are distinguished by a much larger lifting surface, and thus, a different style of flapping flight. The considerations described in the article are an introduction to a fully flexible analysis of the wing in motion. The study of the rigid wing gives the basic knowledge necessary in the further process. The yaw,...
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The Way One Defines Specification Matters: On the Performance Criteria for Efficient Antenna Optimization in Aggregated Bi-Objective Setups
PublicationDesign of antenna structures for real-world applications is a challenging task that often involves addressing multiple design requirements at a time. Popular solution approaches to this class of problems include utilization of composite objectives. Although configuration of such functions has a significant effect on the cost and performance of the optimization, their specific structure is normally determined based on engineering...
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Using terrestrial laser scanning in inventorying of a hybrid constructed wetland system
PublicationThe goal of this paper was to evaluate the possibility of using terrestrial laser scanning (TLS) for inventorying of a hybrid constructed wetland (CW) wastewater treatment plant. The object under study was a turtle-shaped system built in 2015 in Eastern Poland. Its main purpose is the treatment of wastewater from theMuseumand Education Centre of Polesie National Park. The study showed that the CW system had been built in compliance...
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Influence of Parameters of Laser Beam Welding on Structure of 2205 Duplex Stainless Steel
PublicationLaser welding is used in modern industry, having many advantages comparing to traditional welding technologies. Nowadays, industry sectors such as shipbuilding, automotive and aviation can’t be imagined without laser processing technologies. Possibility of increase of welded joint properties, autogenous welding and high level of process automation makes the technology of laser welding perspective part of the industry. Physical...
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Polymodal Method of Improving the Quality of Photogrammetric Images and Models
PublicationPhotogrammetry using unmanned aerial vehicles has become very popular and is already commonly used. The most frequent photogrammetry products are an orthoimage, digital terrain model and a 3D object model. When executing measurement flights, it may happen that there are unsuitable lighting conditions, and the flight itself is fast and not very stable. As a result, noise and blur appear on the images, and the images themselves can...
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Stabilizing forces in trapezoidal sheeting used as a part of the bracing system
PublicationIn the analysis of bracing systems imperfections of the restrained elements should be considered. According to EC3 this effect can be calculated by means of the equivalent stabilizing force, which replaces (in simplified way) initial bow imperfection of the braced element. However, alternative suggestions of the equivalent stabilizing force calculations can be also found in the literature. In this paper segment of the pitched roof...
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EXPERIMENTAL AND NUMERICAL INVESTIGATION ON SPECIMEN GEOMETRY EFFECT ON THE CTOD VALUE FOR VL-E36 SHIPBUILDING STEEL
PublicationThere are special cases in the marine industry, where additional material tests, such as the fracture toughness test, must be performed. Additional fracture toughness tests, such as CTOD (Crack Tip Opening Displacement), are typically performed on three-point bend specimens. The dimension that defines all the specimen dimensions is the thickness of the material to be tested. It is recommended by classification societies (e.g. DNVGL)...
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Detection and Direction-of-Arrival Estimation of Weak Spread Spectrum Signals Received with Antenna Array
PublicationThis paper presents a method for the joint detection and direction of arrival (DOA) estimation of low probability of detection (LPD) signals. The proposed approach is based on using the antenna array to receive spread-spectrum signals hidden below the noise floor. Array processing exploits the spatial correlation between phase-delayed copies of the signal and allows us to evaluate the parameter used to make the decision about the...
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Stabilizing forces in trapezoidal sheeting used as a part of the bracing system
PublicationIn the analysis of bracing systems imperfections of the restrained elements should be considered. According to EC3 this effect can be calculated by means of the equivalent stabilizing force, which replaces (in simplified way) initial bow imperfection of the braced element. However, alternative suggestions of the equivalent stabilizing force calculations can be also found in the literature. In this paper segment of the pitched roof...
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Rheology of Variable Viscosity‐Based Mixed Convective Inclined Magnetized Cross Nanofluid with Varying Thermal Conductivity
PublicationCross nanofluid possesses an extraordinary quality among the various fluidic models to explore the key characteristics of flowing fluid during very low and very high shear rates and its viscosity models depend upon shear rate. The current study establishes the numerical treatment regarding variable viscosity‐based mixed convective inclined magnetized Cross nanofluid with var‐ ying thermal conductivities over the moving permeable...
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EM‐driven constrained miniaturization of antennas using adaptive in‐band reflection acceptance threshold
PublicationNumerical optimization of geometry parameters is a critical stage of the design process of compact antennas. It is also challenging because size reduction is constrained by the necessity of fulfilling imposed electrical performance requirements. Furthermore, full‐wave electromagnetic (EM) analysis needs to be used for reliable performance evaluation of the antenna structure, which is computationally expensive. In this paper, an...
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Methodology of generation of CFD meshes and 4D shape reconstruction of coronary arteries from patient-specific dynamic CT
PublicationDue to the difficulties in retrieving both the time‑dependent shapes of the vessels and the generation of numerical meshes for such cases, most of the simulations of blood flow in the cardiac arteries use static geometry. The article describes a methodology for generating a sequence of time‑dependent 3D shapes based on images of different resolutions and qualities acquired from ECG‑gated coronary artery CT angiography. The precision...
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Application of Multivariate Adaptive Regression Splines (MARSplines) for Predicting Hansen Solubility Parameters Based on 1D and 2D Molecular Descriptors Computed from SMILES String
PublicationA new method of Hansen solubility parameters (HSPs) prediction was developed by combining the multivariate adaptive regression splines (MARSplines) methodology with a simple multivariable regression involving 1D and 2D PaDEL molecular descriptors. In order to adopt the MARSplines approach to QSPR/QSAR problems, several optimization procedures were proposed and tested. The effectiveness of the obtained models was checked via standard...
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STABILITY OF THE INNER SLOPE OF THE POLISH DREDGDIKES RESEARCH DIKE AT STATIONARY FLOW
PublicationFor long duration of the flood the water table can appear on the slope with a problem of out-wash in the case of sand type dike. If the dike corps is covered with less permeable layer some additional push-off forces and shearing can rise in the cover. In both cases the micro stability of the inner slope should be considered at normative high water for homogeneous sand type dike or sand type dike with less permeable covers. The...
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Design and numerical testing of 5-box gfrp shell footbridge
PublicationThe paper formulates new design conditions for composite footbridges, taking into account the material and structural specificity of these objects, i.e. the strength condition, the serviceability condition and the frequency condition. A GFRP composite footbridge labelled with CFB2 code has been designed, with the original superstructure in the form of an opened-closed 5-box girder. The foot and cycle track bridge is simply supported,...
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Compliance tests of the polymer layers used as hydrodynamic bearing coatings
PublicationOperational experience and scientific investigations results showed that polymer lined hydrodynamic bearings can withstand more severe operating conditions compared than white metal bearings. PTFE and PEEK-based coatings are the most frequently used as Babbitt alternatives. Both polymers differ significantly from the each other in material properties. According to catalogue data compression modulus of PTFE, it is about an order...
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Development of a compact microstrip resonant cell aimed at efficient microwave component size reduction
PublicationA comprehensive comparison of a wide collection of compact microstrip resonant cells (CMRCs) found in the extensive body of literature has been presented. The evaluation of different CMRC designs has led to the selection of the most promising CMRC geometry for the efficient miniaturisation of modern microwave components. In order to showcase the vital effectiveness of the approach, the initially selected CMRC has been notably...
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Edge-Guided Mode Performance and Applications in Nonreciprocal Millimeter-Wave Gyroelectric Components
PublicationThe analogies between the behavior of gyromagnetic and gyroelectric nonreciprocal structures, the use of the simple transfer matrix approach, and the edge-guided (EG) wave property, supported in a parallel plate model for integrated magnetized semiconductor waveguide, are investigated in those frequency regions, where the effective permittivity is negative or positive. As with their ferrite counterparts, the leakage of the EG waves...
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THE EFFECT OF NOTCH DEPTH ON CTOD VALUES IN FRACTURE TESTS OF STRUCTURAL STEEL ELEMENTS
PublicationIn elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climat e, the...
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Remote sensing and photogrammetry techniques in diagnostics of concrete structures
PublicationRecently laser scanning technologies become widely used in many areas of the modern economy. In the following paper authors show a potential spectrum of use Terrestrial Laser Scanning (TLS) in diagnostics of reinforced concrete elements. Based on modes of failure analysis of reinforcement concrete beam authors describe downsides and advantages of adaptation of terrestrial laser scanning to this purpose, moreover reveal under which...
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Nonlinear Modeling in Time Domain Numerical Analysis of Stringed Instrument Dynamics
PublicationMusical instruments are very various in terms of sound quality with their timbre shaped by materials and geometry. Materials' impact is commonly treated as dominant one by musicians, while it is unclear whether it is true or not. The research proposed in the study focuses on determining influence of both these factors on sound quality based on their impact on harmonic composition. Numerical approach has been chosen to allowed independent...
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Synchro-photogrammetry in the measurement of objects in motion - the case study
PublicationSynchronous photographs and digital photogrammetry methods in a measurement of objects in motion - the experiment. In the following paper, a case study example of a photogrammetric method based on synchronous digital photographs has been presented. This measurement method is an effective solution for tracking of moving objects, dynamic studies and dimensioning of geometry movements. Nowadays, the use of synchronous photography...
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Influence of orientational disorder on the optical absorption properties in hybrid metal‐halide perovskite CH3NH3PbI3. A combined DFT/TD‐DFT and experimental study.
PublicationAn experimental and theoretical investigation is reported to analyze the relation between the structural and absorption properties of CH3NH3PbI3 in the tetragonal phase. More than 3000 geometry optimizations were performed in order to reveal the structural disorder and to identify structures with the lowest energies. The electronic structure calculations provide an averaged band gap of 1.674 eV, which is in excellent agreement...
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Feedline Alterations for Optimization-Based Design of Compact Super-Wideband MIMO Antennas in Parallel Configuration
PublicationThis letter presents a technique for size reduction of wideband multiple-input-multiple-output (MIMO) antennas. Our approach is a two-stage procedure. At the first stage, the antenna structure is modified to improve its impedance matching. This is achieved through incorporation of an n-section tapered feedline, followed by reoptimization of geometry parameters. Reducing the maximum in-band reflection well beyond the acceptance...
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A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
PublicationSimulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially...
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Thermal failure of a second rotor stage in heavy duty gas turbine
PublicationThe impulse mode of operation and the supply of various types of fuels causes frequent failures even in the heavy duty gas turbines. The paper presents the ravages of second rotor stage failure in a gas turbine. The excessive thermal elongation rise caused by fuel change was indicated as the main cause. We applied nonlinear numerical analysis, preceded by thermodynamic calculations of the turbine and visual inspection of the effects...
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If Gravity is Geometry, is Dark Energy just Arithmetic?
PublicationArithmetic operations (addition, subtraction, multiplication, division), as well as the calculus they imply, are non-unique. The examples of four-dimensional spaces, R^4 and (−L/2,L/2)^4, are considered where different types of arithmetic and calculus coexist simultaneously. In all the examples there exists a non-Diophantine arithmetic that makes the space globally Minkowskian, and thus the laws of physics are formulated in terms...
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Quantitative assessment of the influence of tensile softening of concrete in beams under bending by numerical simulations with XFEM and cohesive cracks
PublicationResults of the numerical simulations of the size effect phenomenon for concrete in comparison with experimental data are presented. In-plane geometrically similar notched and unnotched beams under three-point bending are analyzed. EXtended Finite Element Method (XFEM) with a cohesive softening law is used. Comprehensive parametric study with the respect to the tensile strength and the initial fracture energy is performed. Sensitivity...