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Search results for: ROCK AGGREGATES
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Analysis of temporal leachibility of trace elements to the environment of opoka-rocks used in historical building
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The finite-volume Dirac-Hartree-Fock method for confined relativistic many-electron systems.
PublicationRozpatrzono relatywistyczny układ N-elektronowy ograniczony w skończonej objętośći V. Ograniczenie modelowano za pomocą warunku brzegowego narzuconego na funkcję falową układu na brzegu hiperobjętości VN. Stosując przybliżenie elektronów niezależnych, z zasady wariacyjnej dla energii wyprowadzono układ równań Diraca-Hartree-Focka oraz warunki narzucone na rozwiązania tego układu na brzegu V.
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A design proposal of driving system for roof segments and gantry crane of ecological floating dock
PublicationW pracy przedstawiono propozycję napędu segmentów przesuwnego zadaszenia oraz suwnicy ekologicznego doku pływającego. Proponowany układ napędowy oparto na zastosowaniu elektrycznych silników asynchronicznych z zewnętrznym sterowaniem częstotliwościowym prędkości obrotowej.
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Effects of strongly aggregated silica nanoparticles on interfacial behaviour of water bound to lactic acid bacteria
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Aggregated neutrophil extracellular traps resolve inflammation by proteolysis of cytokines and chemokines and protection from antiproteases
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Time-series analysis of road safety trends aggregated at national level in Europe for 2000-2010
PublicationThe reader will find in this study road safety modelling theory and time-series analysis techniques, applications to long period data of injury accidents and casualities, aggregared at national level
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Polyethylene Terephthalate Wastes as a Partial Replacement for Fine Aggregates in Concrete Mix, Case of Jimma Town, South West Ethiopia
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Potential of Reusing 3D Printed Concrete (3DPC) Fine Recycled Aggregates as a Strategy towards Decreasing Cement Content in 3DPC
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Meso-mechanical modelling of damage in concrete using discrete element method with porous ITZs of defined width around aggregates.
PublicationArtykuł omawia wyniki obliczeń numerycznych pękania dla betonu stosując metodę elementów dyskretnych. Beton był opisany jako materiał 4-fazowy i był poddany zginaniu. W obliczeniach uwzględniono strefy ITZ o skończonej szerokości dookoła wszystkich ziaren kruszywa. Nacisk położono na przebieg mikropęknięć przy kruszywie. Wyniki porównano bezpośrednio z doświadczeniami. Obliczenia wykonano także dla szorstkich ziaren kruszywa....
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Self-compacting grout to produce two-stage concrete
PublicationTraditional concrete (TC) is primarily composed of a mixture of cement, fine and coarse aggregates, and water. TC is made by mixing together all the components before placing them. Using non-traditional concrete (two-stage concrete) to solve and to eliminate the problem of the aggregate segregation which appears in TC and in the self-compacting concrete. Two-stage concrete (TSC) consists of two main components, namely the grout...
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Mechanical Strength and Thermal Properties of Cement Concrete Containing Waste Materials as Substitutes for Fine Aggregate
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Effects of Immobilized RAP Binder on Asphalt-Aggregate Interaction and Performance of 100% Recycled Asphalt Mixtures
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Impact response of two-layered grouted aggregate fibrous concretecomposite under falling mass impact
PublicationTwo-layered Grouted Aggregates Fibrous Concrete Composite (TGAFCC) is a new category concrete which became popular recently and attracted the attention of researchers globally. Recent studies indicated that TGAFCC has notable improvement in mechanical properties, which has been sufficiently documented. However, the impact behaviour of TGAFCC when combined with Glass Fibre Mesh (GFM) and Textile Fibre Mesh (TFM) is still unexplored....
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Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending
PublicationMulti-layered Prepacked aggregate fibrous composite (MLPAFC) is a new type of concrete, which is prepared in two subsequent stages of aggregate-fibre skeleton prepacking and cementitious grouting. In this study, ten MLPAFC mixtures were prepared in three subsequent layers incorporating different contents of four different types of steel fibres. Long and short hooked-end and crimped steel fibers were adopted with 3.0 and 1.5% dosages...
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Size effect at aggregate level in microCT scans and DEM simulation – Splitting tensile test of concrete
PublicationThe paper describes an experimental and numerical study of size effect on concrete cylindrical specimens in splitting tensile test. Own experimental campaign was performed on specimens with 5 various diameters from D = 74, 105, 150, 192 and 250 mm with hardboard loading strips (distributed load according to standard methods) scaled proportionally to the specimen diameter. The crack opening-control system was applied to obtain the...
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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete
PublicationPreplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...
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Rok do parametryzacji 2017 - ocena działalności publikacyjnej - informacje, wskazówki
PublicationW pracy zaprezentowano wyniki analizy sposobu przyznawania punktów dla oceny dorobku naukowego w tym artykułów naukowych, monografii, materia
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The influence of strain on the Verwey transition as a function of dopant concentration: towards a geobarometer for magnetite-bearing rocks
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Research on Temporal Leachability of Trace Elements from Opoka-Rocks in The Aspect of Geochemical Environmental Indicators
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Linear-scaling calculation of Hartree-Fock exchange energy with Non-orthogonal Generalised Wannier Functions
PublicationWe present a method for the calculation of four-centre two-electron repulsion integrals in terms of localised non-orthogonal generalised Wannier functions (NGWFs). Our method has been imple- mented in the ONETEP program and is used to compute the Hartree-Fock exchange energy component of Hartree-Fock and Density Functional Theory (DFT) calculations with hybrid exchange-correlation functionals. As the NGWFs are optimised in situ...
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The Effect of Recycled Fine Aggregate Sourced from Construction and Demolition Waste on the Properties of Epoxy Resin Coatings
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Evaluation of Glass Powder-Based Geopolymer Stabilized Road Bases Containing Recycled Waste Glass Aggregate
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Laboratory Investigation of Critical Factors Affecting Geogrid Reinforcement on Aggregate Base Using Loaded Wheel Tester
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Lightweight alkali-activated composites containing sintered fly ash aggregate and various amounts of silica aerogel
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Comparative analysis of ternary blended cement with clay and engineering brick aggregate for high-performance 3D printing
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Improving Thermal Insulation Properties for Prefabricated Wall Components Made of Lightweight Aggregate Concrete with Open Structure
PublicationPorous concrete is commonly used in civil engineering due to its good thermal insulation properties in comparison with normal concrete and high compression strength in comparison with other building materials. An extremely porous concrete, called ‘lightweight aggregate concrete with open structure’ (LAC), is used in some German plants to produce prefabricated wall components. They are used mainly in hall buildings, e.g. supermarkets....
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Investigations of size effect in concrete at aggregate level - experiments and calculations results using discrete element method
PublicationSize effect is a fundamental phenomenon in concrete. It is characterised by decreasing strength and increasing brittleness of concrete with increasing size. The thesis includes experimental and theoretical elements. The main goal of the thesis were investigations of a size effect at the aggregate level by taking fracture into account with the discrete element method (DEM) for various failure modes. Comprehensive experiments on...
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Self-compacting grout to produce two-stage concrete
PublicationTraditional concrete (TC) is primarily composed...
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Effect of slag coal ash and foamed glass on the mechanical properties of two-stage concrete
PublicationTwo-stage concrete (TSC) is known by various names such as colcrete, Polcrete, preplaced aggregate concrete and prepacked concrete. It is different from traditional concrete in two fundamental ways, namely method of construction and mix proportion. Two-stage concrete (TSC) is defined as firstly, coarse aggregates are placed into the formwork and grout is applied to fill in the between coarse aggregate particles voids. Secondly,...
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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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UNRES-Dock—protein–protein and peptide–protein docking by coarse-grained replica-exchange MD simulations
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Active Double-Layered Films Enriched with AgNPs in Great Water Dock Root and Pu-Erh Extracts
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublicationMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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Effect of gas content in macropores on hydraulic fracturing in rocks using a fully coupled DEM/CFD approach
PublicationW pracy skupiono się na wpływie zawartości gazu w makroporach skał na proces szczelinowania hydraulicznego. Proces został zasymulowany przez połączenie metody elementów dyskretnych (DEM) z obliczeniową dynamiką płynów (CFD) w ramach dwuwymiarowych (2D) warunków izotermicznych. Mechaniczne zachowanie skały zostało zasymulowane za pomocą DEM, a CFD została wykorzystana do opisu zachowanie przepływu laminarnego, dwufazowego płynu...
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Rok, I urodziny Galerii UL, wydarzenie artystyczne, wystawa zbiorowa kolekcji
Publication11 Listopada 2018 roku odbyła się „ZONA” — pierwsze przedsięwzięcie organizowane w ULu, nazywanym jeszcze wtedy galerią, mimo iż przedsiębrane działania od początku wykraczają ambicjami poza to zawężone pole. 11 Listopada 2018 roku byliśmy również świadkami obchodów stulecia odzyskania przez Polskę niepodległości; również my proponowaliśmy fetę z tej okazji, opartą o inne formy świętowania, niż te, do których ustawicznie przyzwyczajała...
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Thermal performance of building envelopes with structural layers of the same density: Lightweight aggregate concrete versus foamed concrete
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Initial Field Validation of Poroelastic Pavement Made with Crumb Rubber, Mineral Aggregate and Highly Polymer-Modified Bitumen
PublicationTire/road noise in most driving conditions dominates other sources of traffic noise. One of the most efficient ways of reducing tire/road noise is to use the so-called “low noise pavement”. According to numerous studies, at present, poroelastic road pavement that is composed of rubber and mineral aggregate and polyurethane or bituminous binder gives the best noise reduction up to 12 dB. Unfortunately, there are many problems with...
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Predicting Performance of Lightweight Concrete with Granulated Expanded Glass and Ash Aggregate by Means of Using Artificial Neural Networks
PublicationLightweight concrete (LWC) is a group of cement composites of the defined physical, mechanical, and chemical performance. The methods of designing the composition of LWC with the assumed density and compressive strength are used most commonly. The purpose of using LWC is the reduction of the structure’s weight, as well as the reduction of thermal conductivity index. The highest possible strength, durability and low thermal conductivity...
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Two-dimensional simulations of concrete fracture at aggregate level with cohesive elements based on X-ray lCT images
PublicationThe paper presents results of two-dimensional meso-scale simulations of fracture in notched concrete beams subjected to three-point bending test. Concrete was assumed as a 4-phase material composed of aggregate grains placed in the cement matrix, interfacial transitional zones (ITZs) and macro-voids. The particle distribution was taken from real concrete beams on the basis of X-ray lCT images. Comprehensive numerical analyses were carried...
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A procedure for the visualization of fingerprint traces on standard and thermal paper using the electron excitation energy of 1,8-diazafluoren-9- one aggregates in a polyvinylpyrrolidone polymer
PublicationThe scope of this study is a new procedure for visualizing dactyloscopic traces on an absorbent surface using a solution based on aggregates of 1,8-diazafluoren-9-one (DFO) in a polyvinylpyrrolidone polymer (PVP). An absorbent surface is defined as a plain or thermal paper, which is considered to be a difficult surface due to its varying chemical composition. In the case of the thermal paper surface, the procedure can be further...
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Experimental and Numerical Investigations of the Effect of Curing Conditions on the Temperature Rise of Concrete
PublicationThis paper presents experimental and numerical studies investigating the impact of three curing conditions on temperature evolution in concrete cubes. The tests were performed on samples of the same volume (3.375 dm3) under different curing conditions: room temperature, insulation boxes, and adiabatic calorimeter. Various cements (Portland cement, Portland composite cement, and blast furnace slag cement) and aggregates (gravel...
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The Mineral Character and Geomechanical Properties of the Transitional Rocks from the Mesozoic-Neogene Contact Zone in the Bełchatów Lignite Deposit
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Continuum wave functions for estimating the electric dipole moment: Calculation based on a multiconfiguration Dirac-Hartree-Fock approximation
PublicationThe multiconfiguration Dirac-Hartree-Fock method is employed to calculate the continuum electron wave functions, which are then used to estimate their contribution to the atomic electric dipole moment (EDM) of 129Xe. The EDM arises from (P,T)-odd electron-nucleon tensor-pseudotensor and pseudoscalar-scalar interactions, the nuclear Schiff moment, the interaction of the electron electric dipole moment with nuclear magnetic moments,...
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Beton w praktyce w rok po wprowadzeniu normy EN 206-1.
PublicationNorma EN 206-1 ''Beton cz.1 Wymagania właściwości, produkcja i zgodność'' dla betonu obowiązuje od stycznia 2004 roku. W referacie podjęto się oceny w jakim stopniu zaawansowane jest stosowanie ww. normy. Opisano również w szerokim stopniu różnice między normą stosowaną wcześniej a normą obecnie obowiązujacą.
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An investigation of structural responses of inverted pavements by numerical approaches considering nonlinear stress-dependent properties of unbound aggregate layer
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Multimodal detection and analysis of a new type of advanced Heinz body-like aggregate (AHBA) and cytoskeleton deformation in human RBCs
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MODELLING OF CONCRETE FRACTURE AT AGGREGATE LEVEL USING DEM BASED ON X-RAY mu CT IMAGES OF INTERNAL STRUCTURE
PublicationThe paper describes two-dimensional meso-scale numerical results of fracture in notched concrete beams under quasi-static three-point bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones (ITZs) and air voids. As a numerical approach, the discrete element method (DEM) was used. The concrete micro-structure in calculations was directly...
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Modelling of concrete facture at aggregate level using DEM based on x-ray mu CT images of internal structure
PublicationW artykule pokazano wyniki dyskretne DEM dla pękania betonu poddanego zginaniu. Beton został symulowany jako ośrodek 4-fazowy. Mikrostrukturę betonu określono na podstawie zdjęć uzyskanych mikro-tomografem. Szczególną uwagę zwrócono na zjawiska mikrostrukturalne podczas zarysowania na poziomie kruszywa.
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Modelling of concrete fracture at aggregate level using FEM and DEM based on X-ray uCT images of internal structure
PublicationArtykuł podejmuje problem pękania w zginanych belkach betonowych. Proces pękania był obserwowany przy zastosowaniu mikrotomografii . Zaobserwowany proces był symulowany numerycznie przy zastosowaniu metody elementów skończonych i metody elementów dyskretnych. Beton był opisany jako materiał 4-fazowy. Otrzymano dobrą zgodność wyników numerycznych z doświadczalnymi.
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Simulations of high-pressure fluid flow in a pre-cracked rock specimen composed of densely packed bonded spheres using a 3D CFD model and simplified 2D coupled CFD-DEM approach
PublicationW artykule zastosowano dwa różne podejścia do opisu jednofazowego przepływu płynu w wstępnie spękanej próbce skały o niskiej porowatości pod wysokim ciśnieniem. Głównym celem pracy było bezpośrednie porównanie rozkładu ciśnień, gęstości i prędkości płynów we wstępnie pękniętej próbce. Zachowanie próbki imitującej skałę zostało opisane przez gęsto upakowane połączone kohezją kulki z nakładającymi się na siebie elementami. Pierwsze...