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Effect of ultrasound on the physicochemical, mechanical and adhesive properties of micro-arc oxidized coatings on Ti13Nb13Zr bio-alloy
PublicationImplant surgeries are increasingly challenging due to their rising number. Achieving the desired biomaterial surface properties to ensure a strong bond with human tissue is a significant issue. This study investigates the influence of ultrasound (US) during the micro-arc oxidation (MAO) process on Ti13Zr13Nb bio-alloy, an area not previously explored, to enhance titanium alloy coatings’ properties for biomedical applications. Porous...
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Compressive and tensile properties of polyurethane foam mimicking trabecular tissue in artificial femoral head bones
PublicationThe presented study aimed to examine the compressive and tensile behavior of the polyurethane foams mimicking trabecular tissue in the artificial human femurs and assess their potential to replicate osteoporotic type of human bone tissue. Two types of Synbone femur models: one of the normal density (model 2350) and one of the lower density (model LD2350), and three types of Sawbones femur models (model 1130-21-8, 1130-21-3, 1130-192)...
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Eco-friendly modification of bitumen: The effects of rubber wastes and castor oil on the microstructure, processability and properties
PublicationThe bitumen industry in the European Union is facing several difficulties, including rising demand, unstable oil supply, rising prices for synthetic polymer modifiers, and a focus on lowering carbon footprint. Bitumen modification with crumb rubber (CR) is one of the most promising solution to these challenges. However, CR-modified bitumen have poor processability and low storage stability. To overcome these flaws we are introducing...
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Chained machine learning model for predicting load capacity and ductility of steel fiber–reinforced concrete beams
PublicationOne of the main issues associated with steel fiber–reinforced concrete (SFRC) beams is the ability to anticipate their flexural response. With a comprehensive grid search, several stacked models (i.e., chained, parallel) consisting of various machine learning (ML) algorithms and artificial neural networks (ANNs) were developed to predict the flexural response of SFRC beams. The flexural performance of SFRC beams under bending was...
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Mechanical performance investigations of a post-tensioned inter-module connection in steel buildings
PublicationConnections in modular steel structures are critical for maintaining structural integrity and facilitating ease of installation. Traditional methods, such as on-site welding, require adherence to complex technical specifications. In contrast, post-tensioned steel bolts offer a viable alternative by potentially reducing on-site labor by up to 50 %, providing substantial strength and simplifying assembly. To accurately assess the...
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Physicochemical and Mechanical Performance of Freestanding Boron-Doped Diamond Nanosheets Coated with C:H:N:O Plasma Polymer
PublicationThe physicochemical and mechanical properties of thin and freestanding heavy boron-doped diamond (BDD) nanosheets coated with a thin C:H:N:O plasma polymer were studied. First, diamond nanosheets were grown and doped with boron on a Ta substrate using the microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Next, the BDD/Ta samples were covered with nylon 6.6 to improve their stability in harsh environments and...
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Effects of Micro-Arc Oxidation Process Parameters on Characteristics of Calcium-Phosphate Containing Oxide Layers on the Selective Laser Melted Ti13Zr13Nb Alloy
PublicationTitania-based films on selective laser melted Ti13Zr13Nb have been formed by micro-arc oxidation (MAO) at different process parameters (voltage, current, processing time) in order to evaluate the impact of MAO process parameters in calcium and phosphate (Ca + P) containing electrolyte on surface characteristic, early-stage bioactivity, nanomechanical properties, and adhesion between the oxide coatings and substrate. The surface...
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Highly Dissipative Materials for Damage Protection against Earthquake-Induced Structural Pounding
PublicationIt is a common situation that seismic excitations may lead to collisions between adjacent civil engineering structures. This phenomenon, called earthquake-induced structural pounding, may result in serious damage or even the total collapse of the colliding structures. Filling the gap between two buildings erected close to one another by using visco-elastic materials can be considered to be one of the most effective methods to avoid...
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New kagome prototype materials: discovery of KV3Sb5, RbV3Sb5, and CsV3Sb5
PublicationIn this work, we present our discovery and characterization of a new kagome prototype structure, KV3Sb5. We also present the discovery of the isostructural compounds RbV3Sb5 and CsV3Sb5. All materials exhibit a structurally perfect two-dimensional kagome net of vanadium. Density-functional theory calculations indicate that the materials are metallic, with the Fermi level in close proximity to several Dirac points. Powder and single-crystal...
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Hyperelastic Microcantilever AFM: Efficient Detection Mechanism Based on Principal Parametric Resonance
PublicationThe impetus of writing this paper is to propose an efficient detection mechanism to scan the surface profile of a micro-sample using cantilever-based atomic force microscopy (AFM), operating in non-contact mode. In order to implement this scheme, the principal parametric resonance characteristics of the resonator are employed, benefiting from the bifurcation-based sensing mechanism. It is assumed that the microcantilever is made...
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Electron collisions with methyl-substituted ethylenes: Cross section measurements and calculations for 2-methyl–2-butene and 2,3-dimethyl–2-butene
PublicationWe report electron-scattering cross sections determined for 2-methyl–2-butene [(H3C)HC==C(CH3)2] and 2,3-dimethyl–2-butene [(H3C)2C=C(CH3)2] molecules. Absolute grand-total cross sections (TCSs) were measured for incident electron energies in the 0.5–300 eV range, using a linear electron-transmission technique. The experimental TCS energy dependences for the both targets appear to be very similar with respect to the shape. In each...
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RMS-based damage identification in adhesive joint between concrete beam and steel plate using ultrasonic guided waves
PublicationAdhesive joints have numerous applications in many branches of industry, such as civil engineering, automotive, aerospace and shipbuilding. As with most structural elements, adhesive joints can experience any damage mechanism, which induces the need for diagnostic testing. Ultrasonic waves are widely used for non-destructive inspection of many structures and their elements, including adhesive joints. Guided wave propagation method...
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Pantographic metamaterials: an example of mathematically driven design and of its technological challenges
PublicationIn this paper, we account for the research efforts that have been started, for some among us, already since 2003, and aimed to the design of a class of exotic architectured, optimized (meta) materials. At the first stage of these efforts, as it often happens, the research was based on the results of mathematical investigations. The problem to be solved was stated as follows: determine the material (micro)structure governed by those...
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Evaluation of the stiffness modulus and phase angle of cold in-place recycled mix-tures for long curing periods
PublicationArticle presents the changes inbehaviour of cold-in place recycling mixtures made using cement and bituminous emulsion (CIR mixtures) after anelongated time of curing. Most of the available literatureregarding change instiffness modulus and phase angle presents resultsfor a maximum of several dozen days,which makesit difficult to predict the behaviour over the whole life of the compacted layer. The article...
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Corrosion Resistance and Structure of Cr−O−N Coatings Formed in Vacuum Arc Plasma Fluxes With PIIID
PublicationCr−O−N-based vacuum arc coatings are very promising for the wear and corrosion protection of various steel parts. The aim of the work was to determine the effect of frequency and amplitude of the pulsed bias voltage (UB) on the elemental and phase composition, mechanical, and corrosion properties of Cr−O−N coatings. They have an amorphous structure with embedded nanosized solid solution crystallites based on CrN with a cubic structure...
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A case study on the rotomolding behavior of black tea waste and bio-based high-density polyethylene composites: Do active compounds in the filler degrade during processing?
PublicationThis study verified the possibility of using waste material from the food industry (black tea) as functional filler of rotomolded biobased high-density polyethylene-based composites. As part of the experimental work, the influence of the materials preparation, i.e., dry blending versus twin-screw extrusion, on the effectiveness of the stabilizing antioxidant effect of the black tea was analyzed. The aim of the work was to verify...
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Influence of Lubrication Water Contamination by Solid Particles of Mineral Origin on Marine Strut Propeller Shafts Bearings of Ships
PublicationThe stern tube or strat bearings are key important component for safety of shipping. Modern global regulations required a low as possible negative impact on environment including lubricants leaking to the sea. The ship owners are looking for reliable and durable solutions. The costs of each ship components are carefully studied. The water lubricated bearings for ship propeller shafts are an environmentally friendly solution. That...
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Anisotropy and compaction gradient assessment on rammed earth specimens through sonic tomography approach
PublicationRammed earth is a traditional construction technique that has recently gained attention because of its benefits from an ecological perspective. The conservation of the existing valuable cultural heritage sites and the quality control of new constructions built with this material require the development and application of practical inspection techniques. This paper explores the application of sonic tests and sonic tomography as...
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Experimental study and numerical simulation on porosity dependent direct reducibility of high-grade iron oxide pellets in hydrogen
PublicationThe transition to more environmentally friendly steel production methods has intensified research into hydrogen-based direct reduction (HyDR) of iron oxide pellets. The aim of this study is to systematically investigate the kinetics of the reduction process, the evolution of porosity and the resulting microstructural changes on the reduction behavior of high-quality pellets during HyDR of iron ore at different temperatures. A modified...
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Influence of Material Thickness on the Ductile Fracture of Steel Plates for Shipbuilding
PublicationIn the shipbuilding industry, the risk of brittle fractures is relatively high because some units operate in arctic or subarcticzones and use high thickness (up to 100 mm) steel plates in their structures. This risk is limited by employing certifiedmaterials with a specific impact strength, determined using the Charpy method (for a given design temperature) and byexercising control over the welding processes (technology qualification,...
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Closed Form Constraint Equations Used to Express Frictionless Slip of Multibody Systems Attached to Finite Elements—Application to a Contact between a Double Pendulum and a Beam
PublicationThis paper focuses on the numerical modeling of the dynamics of mechanical systems. Robots that can inspect high-voltage lines inspired this research. Their control systems must anticipate potential grab positions appropriately. We intend to formulate equations dedicated to the numerical description of the robot/cable contact. The investigated problem is not straightforward, since parts of the modeled systems are numerically inhomogeneous....
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On mechanics of piezocomposite shell structures
PublicationThis study presents an original and novel investigation into the mechanics of piezo-flexo-magneto-elastic nanocomposite doubly-curved shells (PFMDCSs) and the ability to detect the lower and higher levels of electro-magnetic fields. In this context, by utilizing the first-order shear deformation shell model, stresses and strains are acquired. By imposing Hamilton's principle and the von Kármán approach, the governing equations...
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Continuum orbitals in low energy scattering of electrons from Ar, Kr, Xe, Rn and Og atoms
Open Research DataThe dataset includes relativistic continuum electron wave functions (continuum orbitals, continuum spinors) for elastic scattering of electrons from Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn) and Oganesson (Og) atoms, calculated using the Multiconfiguration Dirac-Hartree-Fock method (MCDHF), at very low electron energies (0.0001 - 0.001 eV). Only...
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Fracture in Asymmetric Bonded Joints
PublicationAdhesion was studied in asymmetric bonded joints using fracture mechanics tests. The asymmetric bonded joints consist of two different type and/or thickness materials bonded by an adhesive. Mentions of asymmetric bonded joint tests employed so far are rare in the literature. They are imperfect and therefore are not standardized. Accordingly three new tests were introduced in this work to study bonded joints. The new metrological...
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Algorytm ekstrakcji cech biometrycznych twarzy
PublicationW referacie zawarto opis metody automatycznej lokalizacji oraz parametryzacji punktów charakterystycznych w obrazie twarzy. Do lokalizacji punktów charakterystycznych wykorzystano zmodyfikowany algorytm EBGM (ang. Elastic Bunch Graph Matching). Algorytm ten pozwala lokalizować punkty w obrazie przy założeniu niezmienności topologii grafu połączeń między nimi.W referacie przedstawiono podstawy teoretyczne metody oraz zaimplementowany...
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Micro-cracking pattern recognition of hybrid CNTs/GNPs cement pastes under three-point bending loading using acoustic emission technique
PublicationThe generation of microcracks has an important influence on the behaviour of concrete structures. In this study, the acoustic emission (AE) technique was used to investigate the fracture phenomena and micro-cracking behavior of hybrid carbon nanotubes (CNTs, the 1-D allotrope of carbon atoms) and graphene nanoplatelets (GNPs, 2D monolayer of sp2-hybridized carbon atoms), cement composites under three-point bending loading. In...
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On a flexomagnetic behavior of composite structures
PublicationThe popularity of the studies is getting further on the flexomagnetic (FM) response of nano-electro-magneto machines. In spite of this, there are a few incompatibilities with the available FM model. This study indicates that the accessible FM model is inappropriate when considering the converse magnetization effect that demonstrates the necessity and importance of deriving a new FM relation. Additionally, the literature has neglected...
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Electron-scattering cross sections for selected alkyne molecules: Measurements and calculations
PublicationWe report cross-section results from experimental and theoretical studies on electron collisions with 1-butyne (HC≡C–CH2CH3) and acetylene (HC≡CH) molecules and from computations for a propyne (HC≡C–CH3) molecule. Absolute grand -total electron-scattering cross sections (TCSs) were measured at impact energies ranging from about 0.5 to 300 eV using the linear electron-transmission method. The TCS energy curve for 1-butyne has a...
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Applications of Tensor Analysis in Continuum Mechanics
PublicationA tensor field is a tensor-valued function of position in space. The use of tensor fields allows us to present physical laws in a clear, compact form. A byproduct is a set of simple and clear rules for the representation of vector differential operators such as gradient, divergence, and Laplacian in curvilinear coordinate systems. The tensorial nature of a quantity permits us to formulate transformation rules for its components...
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Impacts in case of triple unilaterally constrained system
PublicationThe this paper focus on the behaviour of a “rigid” body biting into another “rigid” body, with some nonzero relative velocity. In the presently considered case, the introduced collision appears between a selected element of a multibody structure and its reference body being interpreted as the motionless ground. Instead of the classic case, described in a number of dissertations, where a single impacting contact is considered, three...
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Implementation of failover and load balancing algorithms in SIP PBX High Availability system
PublicationGoal of the project was to design a High Availability SIP VoIP system that guarantees access to additional services like auto-attendent and automatic call distribution. The realization of the project required system to have load balancing and failover algorithms implemented. From the end users’ point of view the whole system had to figure as a single element. After taking under consideration the known methods of implementations...
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Wiktoria Wojnicz dr hab. inż.
PeopleDSc in Mechanics (in the field of Biomechanics) - Lodz Univeristy of Technology, 2019 PhD in Mechanics (in the field of Biomechanics) - Lodz Univeristy of Technology, 2009 (with distinction) List of papers (2009 - ) Wojnicz W., Wittbrodt E., Analysis of muscles' behaviour. Part I. The computational model of muscle. Acta of Bioengineering and Biomechanics, Vol. 11, No.4, 2009, p. 15-21 Wojnicz W., Wittbrodt E., Analysis of...