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IMPACT-TOUGHNESS INVESTIGATIONS OF DUPLEX STAINLESS STEELS
PublicationDuplex stainless steels are very attractive constructional materials for use in aggressive environments because of their several advantages over austenitic stainless steels. Duplex steels have excellent pitting and crevice corrosion resistance, are highly resistant to chloride stress-corrosion cracking and are about twice as strong as common austenitic steels. Better properties are associated with their microstructures consisting...
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Influence of Rock Dust Additives as Fine Aggregate Replacement on Properties of Cement Composites—A Review
PublicationConcrete production consumes enormous amounts of fossil fuels, raw materials, and is energy intensive. Therefore, scientific research is being conducted worldwide regarding the possibility of using by-products in the production of concrete. The objective is not only to identify substitutes for cement clinker, but also to identify materials that can be used as aggregate in mortar and concrete productions. Among the potential alternative...
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Impact of low-temperature sintering on the Fe-based amorphous coatings
PublicationBulk metallic glasses (BMGs) have gained a lot of attention in recent years due to their outstanding properties such as high hardness and excellent wear and corrosion resistance. However, they are restricted in industrial applications due to their extreme brittleness. Iron based amorphous coatings from BMGs are the best solution to use them by overcoming the problem of extreme brittleness. The coatings can be sprayed by various...
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Ball milling induced borophene flakes fabrication
PublicationTo fill the knowledge gap for borophene, as the youngest member of the two-dimensional (2D)nanomaterials family, a facile, cost effective, scalable and reproducible fabrication route is still stronglyrequired. Among so far studied techniques the potential of pure mechanical processes such as ballmilling is not explored yet. Therefore, in this contribution, we explore the efficiency...
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One More Step Towards a Circular Economy for Thermal Insulation Materials—Development of Composites Highly Filled with Waste Polyurethane (PU) Foam for Potential Use in the Building Industry
PublicationThe rapid development of the building sector has created increased demand for novel materials and technologies, while on the other hand resulting in the generation of a severe amount of waste materials. Among these are polyurethane (PU) foams, which are commonly applied as thermal insulation materials. Their management is a serious industrial problem, due to, for example, their complex chemical composition. Although some chemical...
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Advanced Mechanics of Marine Structures I, MSc, Summer 2022-2023, [L,T], PG_00051723
e-Learning Courses1. Literature overview, definition of marine and offshore structures, ocean engineering technologies and mechanical aspects, structural systems applied, jack-up drilling platforms and structural elements. 2. Tensor algebra fundamentals, stress and small strain states of a solid, constitutive relations. 3. SDOF and MDOF dynamic systems, damping and added masses in offshore vibrations, generalised eigenvalue problem, forced vibrations...
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Efficient production of Staphylococcus simulans lysostaphin in a benchtop bioreactor by recombinant Escherichia coli.
PublicationLysostaphin is an enzyme with bactericidal activity against Staphylococcus aureus and other staphylococcal species. In spite of many advantages and promising results of preliminary research, the enzyme is still not widely used in medicine, veterinary or as a food preservative. One of the most important factors limiting application of the enzyme in clinical or technological practice is the high costs of its production. In the present...
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The potential of raw sewage sludge in construction industry – A review
PublicationExcess sewage sludge produced in any municipal or industrial wastewater treatment plant becomes a serious problem due to its increasing amount. This increase is related to the improvement of treatment technologies, expansion of sewage systems and the development of new industrial plants. The implementation and development of new technologies related to the utilization of sewage sludge is currently based on treating it as a substrate....
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Tensile modulus of human orbital wall bones cut in sagittal and coronal planes
PublicationIn the current research, 68 specimens of orbital superior and/or medial walls taken from 33 human cadavers (12 females, 21 males) were subjected to uniaxial tension untill fracture. The samples were cut in the coronal (38 specimens) and sagittal (30 specimens) planes of the orbital wall. Apparent density (ρapp), tensile Young’s modulus (E-modulus) and ultimate tensile strength (UTS) were identified. Innovative test protocols were...
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Advanced Hysteretic Model of a Prototype Seismic Isolation System Made of Polymeric Bearings
PublicationThe present paper reports the results of acomprehensive study designed to verify the effectiveness of an advanced mathematical model in simulating the complex mechanical behaviour of a prototype seismic isolation system made of polymeric bearings (PBs). Firstly, in order to construct the seismic bearings considered in this research, a specially prepared flexible polymeric material with increased damping properties was employed....
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Comparative Analysis of Laboratory-Made and Industrial-Made Sewage Sludge Ash: Implications for Effective Management Strategy Development
Publicationfirst_pageDownload PDFsettingsOrder Article Reprints Open AccessArticle Comparative Analysis of Laboratory-Made and Industrial-Made Sewage Sludge Ash: Implications for Effective Management Strategy Development by Bartłomiej Michał Cieślik 1,*ORCID,Oskar Ronda 1ORCID,Elżbieta Grządka 2ORCID,Jolanta Orzeł 2 andJustyna Płotka-Wasylka 1 1 Department of Analytical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gabriela...
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Effect of bio-polyol molecular weight on the structure and properties of polyurethane-polyisocyanurate (PUR-PIR) foams
PublicationThe increasing interest in polyurethane materials has raised the question of the environmental impact of these materials. For this reason, the scientists aim to find an extremely difficult balance between new material technologies and sustainable development. This work attempts to validate the possibility of replacing petrochemical polyols with previously synthesized bio-polyols and their impact on the structure and properties...
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Diagnostics of high-voltage varistor quality using resonant ultrasound spectroscopy
PublicationResonant spectroscopy is an effective nondestructive testing method focused on defects detection in tested objects. Resonance spectrum contains an information about the mechanical properties and particularly about the structural homogeneity of the whole object. A swept frequency method has been used to measure the selected resonant frequencies range. The system for measurement of resonant ultrasound spectroscopy of high-voltage...
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Determination of Failure Causes of a Steam Turbine Casing
PublicationThe paper presents results of research and failure analysis undertaken to determine failure causes of a steam turbine casing. After 130,000 hours of service the crack in a outer shell of the turbine casing was found. The inner shell of the casing was made of cast steel grade G21CrMoV5-7, and the outer shell of grade G20CrMo4-5. Following research were performed in order to determine causes of the casing failure: chemical analysis;...
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Modelling of heat and mass transfer through wooden buildings
PublicationThe aim of this review paper is to examine the most recent available studies dealing with theoretical, numerical and experimental aspects related to modelling of heat and mass transfer through wooden buildings. The main thermophysical, mechanical and hygrometric properties of wood are firstly discussed. Then, the basic governing equations of heat and mass transfer phenomena are presented. A detailed description of the physical...
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High-density polyethylene/EPDM rubber blend composites of boron compounds for neutron shielding application
PublicationNovel materials with neutron shielding property were fabricated by incorporating boron compounds into highdensity polyethylene (HDPE)/Ethylene propylene diene monomer rubber (EPDM) blends. A detailed investigation on the morphological, thermal, mechanical, and neutron attenuation properties of suitable proportion of HDPE/EPDM blend with boric acid (BA), boron carbide (BC), and nano boron carbide (NBC) were performed. Morphology...
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Electrophoretically deposited titanium and its alloys in biomedical engineering: Recent progress and remaining challenges
PublicationOver the past decade, titanium implants have gained popularity as the number of performed implantation operations has significantly increased. There are a number of methods for modifying the surface of biomaterials, which are aimed at extending the life of titanium implants. The developments in this field in recent years have required a comprehensive discussion of all the properties of electrophoretically deposited coatings on...
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Which Curve Fits Best: Fitting ROC Curve Models to Empirical Credit-Scoring Data
PublicationIn the practice of credit-risk management, the models for receiver operating characteristic (ROC) curves are helpful in describing the shape of an ROC curve, estimating the discriminatory power of a scorecard, and generating ROC curves without underlying data. The primary purpose of this study is to review the ROC curve models proposed in the literature, primarily in biostatistics, and to fit them to actual credit-scoring ROC data...
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Diamond-based protective layer for optical biosensors
PublicationOptical biosensors have become a powerful alternative to the conventional ways of measurement owing to their great properties, such as high sensitivity, high dynamic range, cost effectiveness and small size. Choice of an optical biosensor's materials is an important factor and impacts the quality of the obtained spectra. Examined biological objects are placed on a cover layer which may react with samples in a chemical, biological...
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The influence of crude glycerol and castor oil-based polyol on the structure and performance of rigid polyurethane-polyisocyanurate foams
PublicationIn 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...
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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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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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Docking simulations, Molecular properties and ADMET studies of novel Chromane6,7diol analogues as potential inhibitors of Mushroom tyrosinase
PublicationResearch on inhibition of tyrosinase enzyme has attained significant value, because tyrosinase inhibitors have potential applications in medicine, cosmetics (as whitening agents) and in agriculture (as bioinsecticides). Determination and elucidation of new tyrosinase inhibitors are not only beneficial for medical purposes, but their promising applications in improving food quality and nutritional...
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Multidirectional Characterization of Phytochemical Profile and Health-Promoting Effects of Ziziphora bungeana Juz. Extracts
PublicationZiziphora species (Lamiaceae) have been used in traditional medicine as sedatives, anti-septics, carminatives, or expectorants. Despite their common applications in phytotherapy, there is still lack of evidence about the composition of their extracts and its impact on biological properties of the plants. The aim of this study was to evaluate the content of Ziziphora bungeana, a less studied species growing in Kazakhstan, using...
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The Characteristic of Surface Layers on Austenitic Stainless SteelAfter Glow-discharge Nitriding Process.
PublicationThis paper presents investigation of surface layers. The diffusion layers were produced by using different parameters of reactive atmosphere (N2:H2). The research of the surface layers was performed using scanning electron microscope (SEM). The results of energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) analysis are presented. Research reveals the influence of chemical constitution of reactive atmosphere on the...
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Evaluating Gelatin-Based Films with Graphene Nanoparticles for Wound Healing Applications
PublicationIn this study, gelatin-based films containing graphene nanoparticles were obtained. Nanoparticles were taken from four chosen commercial graphene nanoplatelets with different surface areas, such as 150 m2/g, 300 m2/g, 500 m2/g, and 750 m2/g, obtained in different conditions. Their morphology was observed using SEM with STEM mode; porosity, Raman spectra and elemental analysis were checked; and biological properties, such as hemolysis...
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Biomechanical testing of bioactive bone cements – a comparison of the impact of modifiers: antibiotics and nanometals
PublicationApart from its bone filler and fracture stabilizing function, bone cement can be used as a carrier of bioactive substances, and such modified bone cement can protect the implant against microorganisms, treat local infections and combat bacteria introduced during the surgical procedure. In this paper, the effects of modifying antibiotics and nanosilver on the biomechanical properties of bone cement were examined. The following tests...
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Preparation and Characterization of Films Based on Disintegrated Bacterial Cellulose and Montmorillonite
PublicationThe food packaging materials from natural polymers including polysaccharides offer an ecologically important alternative to commonly used synthetic, non-biodegradable counterparts. The purpose of this work was to modify of bacterial cellulose (BC) leading to the improvement of its functional properties in terms of use as a food packaging material. Effects of disintegration of BC and addition of montmorillonite (MMT) on its water...
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Preparation and Characterization of Diamond-like Carbon Coatings for Biomedical Applications—A Review
PublicationDiamond-like carbon (DLC) films are generally used in biomedical applications, mainly because of their tribological and chemical properties that prevent the release of substrate ions, extend the life cycle of the material, and promote cell growth. The unique properties of the coating depend on the ratio of the sp3/sp2 phases, where the sp2 phase provides coatings with a low coefficient of friction and good electrical conductivity,...
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Applying molecular dynamics simulation to take the fracture fingerprint of polycrystalline SiC nanosheets
PublicationGraphene-like nanosheets are the key elements of advanced materials and systems. The mechanical behavior of the structurally perfect 2D nanostructures is well documented, but that of polycrystalline ones is less understood. Herein, we applied molecular dynamics simulation (MDS) to take the fracture fingerprint of polycrystalline SiC nanosheets (PSiCNS), where monocrystalline SiC nanosheets (MSiCNS) was the reference nanosheet....
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Thermoplastic polyurethanes derived from petrochemical or renewable resources: A comprehensive review
PublicationThermoplastic polyurethanes (TPUs) materials are obtained by the reaction of polyol (ether-, ester-, and carbonate-based diols with average molecular weight in the range from 1,000 to 3,000 g/mol) with aliphatic or aromatic diisocyanates. Synthesized materials consist of the hard and soft segments which are separated in different level. All mechanical and thermal properties of TPUs depend on the chemical structure of used monomers,...
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Carburization Behavior of High-Grade Pellets After Direct Reduction in Pure Hydrogen
PublicationCarburization is a critical aspect in the iron and steel industry as it significantly affects the mechanical and chemical properties of the final product. This study provides a comprehensive analysis of the carburization potential of high-grade quality iron ore pellets after direct reduction in pure hydrogen. The results show that the porosity of the pellets has a significant impact on the efficiency and success of the direct reduction...
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Cold plasma treatment of tannic acid as a green technology for the fabrication of advanced cross-linkers for bioactive collagen/gelatin hydrogels
PublicationTannic acid (TA) is a natural compound studied as the cross-linker for biopolymers due to its ability to form hydrogen bonds. There are different methods to improve its reactivity and effectiveness to be used as a modifier for biopolymeric materials. This work employed plasma to modify tannic acid TA, which was then used as a cross-linker for fabricating collagen/gelatin scaffolds. Plasma treatment did not cause any significant...
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Progress in non-isocyanate polyurethanes synthesized from cyclic carbonate intermediates and di- or polyamines in the context of structure–properties relationship and from an environmental point of view
PublicationCommercially, polyurethanes are produced by the reaction of diisocyanates, polyols (polyester or polyether) and low molecular weight chain extender. Toxicity, moisture sensitivity and phosgene-based synthesis of diisocyanates resulted in investigations focused on obtaining the non-isocyanate polyurethanes (NIPUs). This work presents the review of synthesis and structure–properties relationship of non-isocyanate polyurethanes obtained...
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
PublicationHot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point...
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Nanoindentation tests titanium alloy Ti-6Al-4V after interference laser treatment
PublicationThe study aimed was to assess selected mechanical properties of surface layers obtained after interference laser treatment – DLIL of titanium alloy Ti-6Al-4V used for implants. The samples were melted in still air at room temperature, for this purpose Nd:YAG laser was used, the number of laser shots was variable. Next, nanoindentation tests were performed, based on which Young’s modulus and nanohardness in the obtained surface...
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Novel bio-based thermoplastic poly(ether-urethane)s. Correlations between the structure, processing and properties
PublicationThe main purpose of this work was to analyze the effect of the number of unreacted isocyanate groups and the [NCO]/[OH] molar ratio during the chain extension of a prepolymer during the polymerization process on the structure, processing and selected properties of thermoplastic poly(ether-urethane)s. Three series of novel thermoplastic polyurethanes were obtained via a prepolymer route. Three prepolymers were synthesized from diisocyanate...
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Focused ion beam-based microfabrication of boron-doped diamond single-crystal tip cantilevers for electrical and mechanical scanning probe microscopy
PublicationIn this paper, the fabrication process and electromechanical properties of novel atomic force microscopy probes utilising single-crystal boron-doped diamond are presented. The developed probes integrate scanning tips made of chemical vapour deposition-grown, freestanding diamond foil. The fabrication procedure was performed using nanomanipulation techniques combined with scanning electron microscopy and focused ion beam technologies....
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Recent advances in electrochemically surface treated titanium and its alloys for biomedical applications: A review of anodic and plasma electrolytic oxidation methods
PublicationNowadays, titanium and its alloys are widely used materials in implantology. Nevertheless, the greatest challenge is still its appropriate surface treatment in order to induce optimal properties, which facilitates formation of a permanent bond between the implant and human tissue. The use of electrochemical treatment such as anodic oxidation or plasma electrolytic oxidation allows for the production of porous coating that mimics...
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Supporting Compliance with Security Standards by Trust Case Templates
PublicationTrust Cases are used to justify that a given object (a system, an infrastructure, an organization) exhibits certain properties. One of possible applications of trust cases is related to the processes of achieving and demonstrating the compliance with standards. A Trust Case Template derived from a given standard constitutes a skeleton of justification (encompassing evidence and argumentation) of the compliance with the standard....
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Unraveling the role of boron dimers in the electrical anisotropy and superconductivity in boron-doped diamond
PublicationWe use quantum mechanics (QM) to determine the states formed by B dopants in diamond. We find that isolated B sites prefer to form BB dimers and that the dimers pair up to form tetramers (BBCBB) that prefer to aggregate parallel to the (111) surface in the <110> direction, one double layer below the H-terminated surface double layer. These tetramers lead to metallic character (Mott metal Insulator Transition) with holes in the...
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Assessment of the usefulness of bacterial cellulose produced by Gluconacetobacter xylinus E25 as a new biological implant
PublicationBionanocellulose (BNC) is a clear polymer produced by the bacterium Gluconacetobacter xylinus. In our current study, “Research on the use of bacterial nanocellulose (BNC) in regenerative medicine as a function of the biological implants in cardiac and vascular surgery”, we carried out material analysis, biochemical analysis, in vitro tests and in vivo animal model testing. In stage 1 of the project, we carried out physical and...
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Exemplary AFM application in cosmetology
Open Research DataAtomic force microscopy can be used in the diagnosis of the condition of human tissues such as skin, nails and hair. This is obviously related to the use of a variety of cosmetic products and can be understood as an attempt to assess their long-term impact on human appearance and health. An example may be the studies presented in [1] indicating the...
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Angular welding distortion - one sided fillet weld
Open Research DataWelding is the basic method of joining ship hull elements during its construction. However, this method of joining structural elements generates shrinks. Shrinks causes deformation of the entire welded structure, both linear and angular. In the shipbuilding industry, there is a tendency to oversize fillet welds, at the design as well as manufacturing...
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Ground tire rubber thermo-mechanically devulcanized in the presence of waste engine oil as asphalt modifier
PublicationCross-linked elastomers network is main limitation for industrial usage of ground tire rubber (GTR) as asphalts’ and road pavements modifier. GTR was thermo-mechanically devulcanized via extrusion in the presence of waste engine oil (WEO) at temperature ranges from 150 to 280 °C. Combined impact of WEO content and extruder barrel temperature on the change of cross-linked structure of degraded GTR (DTGR) was investigated through...
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A two dimensional approach for modelling of pennate muscle behaviour
PublicationThe purpose of this study was to elaborate a two-dimensional approach for unipennate and bipennate striated skeletal muscle modelling. Behavior of chosen flat pennate muscle is modelled as a rheological system composed of serially linked passive and active fragments having different mechanical properties. Each fragment is composed of three elements: mass element, elastic element and viscous element. Each active fragment furthermore...
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Analysis of the cyclic load-unload-reload tests of VALMEX aged fabric
PublicationThe paper presents mechanical response of the VALMEX fabric during the cyclic loading-unloading and re-loading experiments. Two types of the aged material used for nearly 20 years as the roofing of the Forest Opera in Sopot (Poland) have been tested. The results have been separately obtained for the warp and fill di-rections. The comparative analysis has revealed that the material aged in service is more durable in the fill di-rection,...
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Wet H2S corrosion and degradation of pipeline in amine regeneration system
PublicationThe paper presents the results of NDT examinations, metallographic tests and risk assessment of degradation related to corrosion of amine regeneration unit in a desulphurisation system. Intensive corrosion resulting from acid gases environment upon water condensation causes perforation of the pipeline. Detailed analysis reveals cracking related to the mechanism of wet H2S. Hydrogen penetration, resulting from the wet H2S process,...
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Preparation, characterization and antimicrobial activity of polyvinyl alcohol/gum arabic/chitosan composite films incorporated with black pepper essential oil and ginger essential oil
PublicationIn this study, biocomposite films based on polyvinyl alcohol (PVA), gum arabic (GA) and chitosan (CS) incorporated with BPEO and GEO were fabricated by solvent casting method. FTIR, XRD, SEM and DSC were performed with mechanical and antimicrobial properties of PVA/GA/CS films with and without BPEO and GEO. The BPEO and GEO incorporated PVA/GA/CS films were significantly inhibited the growth of Bacillus cereus, Staphylococcus aureus,...
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Impact of thermal loading into the structural performance of ships: A review
PublicationThe presented study reviews the recent advances done regarding the impact of thermal loading on the structural performance of ships. Firstly, the studies related to the mechanical and thermal properties of typical materials used in shipbuilding are outlined. Secondly, a brief introduction to the heat transfer analysis, Finite Element modelling and thermal stresses is provided. Finally, the review of papers dealing with the structural...