bluuebunny/crossref_metadata_2025 huggingface dataset:
A Survey of 3D Rigid Registration Methods for RGB-D Cameras
Authors: Morell-Gimenez Vicente , Saval-Calvo Marcelo , Villena-Martinez Victor , Azorin-Lopez Jorge , Garcia-Rodriguez Jose , Cazorla Miguel , Orts-Escolano Sergio , Fuster-Guillo Andres
Published: March 2018

Registration of multiple 3D data sets is a fundamental problem in many areas. Many researches and applications are using low-cost RGB-D sensors for 3D data acquisition. In general terms, the registration problem tries to find a transformation between two coordinate systems that better aligns the point sets. In order to review and describe the state-of-the-art of the rigid registration approaches, the authors decided to classify methods in coarse and fine. Due to the high variety of methods, they have made a study of the registration techniques, which could use RGB-D sensors in static scenarios. This chapter covers most of the expected aspects to consider when a registration technique has to be used with RGB-D sensors. Moreover, in order to establish a taxonomy of the different methods, the authors have classified those using different characteristics. As a result, they present a classification that aims to be a guide to help the researchers or practitioners to select a method based on the requirements of a specific registration problem.
Applying Cellular Automata-Based Structures to Hyperspectral Image Processing
Authors: Torres Blanca María Priego , Fernández Richard J. Duro
Published: March 2018

This chapter addresses the problem of processing hyperspectral images (HI) and sequences leading to high efficiency implementations. A new methodology based on the application of cellular automata (CA) is presented to solve two different processing tasks, the segmentation and denoising of HI and sequences, respectively. CA structures present potential benefits over traditional approaches since they are computationally efficient and can adapt to the particularities of the task to be solved. However, it is necessary to generate an appropriate rule set for each particular problem, which is usually a difficult task. The generation of the rule sets is handled here following a new methodology based on the application of evolutionary algorithms and using synthetic low-dimensionality images and sequences as training datasets, which results in CA structures that can be used to process HI and sequences successfully, thus avoiding the problem of lack of labeled reference images. Both processing approaches have been tested over real HI providing very competitive results.
In Situ XRD Experiments on the Growth of Expanded Austenite Using Different Process Gases
Authors: Balogh-Michels Zoltán , Faeht Alexander , Kleiner Simon , Margraf Patrick , Dommann Alex , Neels Antonia
Published: March 2018

In this work we show our result of in-situ nitrocarburizing and nitriding treatments AISI316L specimens. Part of the samples have been depassivated ex-situ and coated with a Ni layer, while other specimens received in-situ depassivation. Processing was carried out in a custom built reaction chamber attached to a Bruker D8 Advance diffractometer. We monitored the 111 peak of both the base material and expanded austenite. From the shrinkage of the base material peak the total thickness of the expanded austenite can be determined. Applying both N and C resulted in a more than 10 times faster growth of the expanded austenite than with N only. The growth is thermally activated. The activation energy for nitrocarburizing is 164 kJ/mol. This is in agreement with the activation energy of the diffusion of interstitials. Detailed analysis of the expanded austenite peak allowed the derivation of a “master curve” for the composition depth profile. This suggest that two interacting process controls the evolution. The width of the reaction zone is limited by the diffusion at low concentration side. The total concentration is determined by the reaction at the interface.
Influence of Ultrafine-Grained Structure of Martensitic and Austenitic Steels on Diffusion Processes at Low-Temperature Ion Nitriding
Authors: Khusainov Uldash Gamirovich , Ramazanov Kamil Nurulaeyevich , Esipov Roman Sergeevich
Published: March 2018

The paper discusses the influence of ultrafine-grained structure of martensitic and austenitic steels on diffusion processes at low-temperature ion nitriding. The microstructure of ultrafine-grained steels was analysed before and after nitriding. Depth distributions of microhardness are given depending on the class and structure of steels. The study proves that ultrafine-grained structure of steels obtained by high pressure deformation by torsion allows an increased growth rate of the diffusion layer at nitriding.
Redistribution of Metallic Impurities in Si during Annealing and Oxidation: W and Fe
Authors: Portavoce Alain , De Luca Anthony , Burle Nelly , Texier Michaël
Published: March 2018

Atomic redistribution of W and Fe in Si were studied using secondary ion mass spectrometry and transmission electron microscopy. W diffusion experiments performed during isothermal annealing and during Si oxidation show that W atoms should use at least two different diffusion mechanisms. Experimental diffusion profiles can be well simulated by considering the simultaneous use of three different W diffusion mechanisms: the dissociative and the kick-out mechanisms, as well as an original mechanism based on the formation of a W-Si self-interstitial pair located on the interstitial Si sub-lattice. Fe redistribution was studied during the oxidation of a Fe-contaminated Si wafer. Fe is shown to be first pushed-out in Si by the mobile SiO2/Si interface, and thus to form Fe silicides precipitates at this interface. The silicide precipitates, which can exhibit a core-shell structure, appear to move with the SiO2/Si interface thanks to an oxidation/dissolution mechanism in the SiO2 and a nucleation/growth mechanism in the Si matrix. Furthermore, the rate difference between Si and Fe silicide precipitate oxidation leads to the formation of Si pyramidal defects at the SiO2/Si interface.
Impact of a Constant Magnetic Field on Decomposition of Cu-Be-Ni-Based Solid Solution
Authors: Post Regina , Osinskaya Julia V. , Divinski Sergiy V. , Pokoev Alexander V. , Wilde Gerhard
Published: March 2018

Impact of a constant magnetic field on decomposition of supersaturated solid solution is investigated for the system Cu-Be-Ni. A technical bronze Cu-1.9Be-0.3Ni (in wt.%) was water-quenched after holding at 800°C (0.5 h) and subsequently heat treated at 325°C, 350°C and 400°C for 1 hour without and with application of a constant magnetic field of 0.7 T. The annealing in magnetic field is found to influence significantly the precipitation characteristics in diamagnetic Cu-based alloy, especially at 325°C. The nucleation barriers for discontinuous precipitation at grain boundaries are decreased, while the growth rates seem to be decreased, too, in magnetic field. A possible mechanism of the magnetic effect on discontinuous precipitation in the Cu-based is discussed.
Resonant Behavior of Sn Diffusion Coefficient in α-Fe in Pulsed Magnetic Field at 730-750 °С
Authors: Fedotov A.A. , Pokoev Alexander V. , Divinski Sergiy V.
Published: March 2018

The impact of a pulsed magnetic field on Sn diffusion in α-Fe is investigated within the magnetic field intensity range of 79.6–398.0 kА/m and the frequency range of 1–21 Hz at 730, 740, and 750 °С. The solute diffusion coefficients were measured by X-ray diffraction analysis. The pulsed magnetic field was found to influence significantly the diffusion coefficients of Sn in α-Fe. A resonant maximum of the bulk diffusion coefficient is observed at the frequency of 13 Hz and the magnetic field intensity of 398.0 kА/m. Possible mechanisms of the established magneto-diffusion coupling are discussed.
High-Throughput Determination of Interdiffusivities for Ni-Al-Cr Alloys at 1173 K through a Combination of Diffusion Multiple and Numerical Inverse Method
Authors: Chen Wei Min , Zhang Li Jun
Published: March 2018

In this report, a combination of the diffusion multiple technique and the recently developed numerical inverse method was employed for a high–throughput determination of interdiffusivity matrices in Ni–Al–Cr alloys. A face–centered cubic (fcc) quinary Ni–Al–Cr diffusion multiple at 1173 K was carefully prepared by means of the hot–pressing technique. Based on the composition profiles measured by the field emission electron probe micro analysis (FE–EPMA), the composition–dependent interdiffusivity matrices in ternary Ni–rich Ni–Al–Cr system at 1173 K were then efficiently determined using the numerical inverse method.
Numerical Analysis of Diffusion-Controlled Internal Corrosion by the Cellular Automata Approach
Authors: Krupp Ulrich , Jahns Katrin , Balinski Kamil , Wübbelmann Jürgen
Published: March 2018

The cellular automata method offers a promising approach to describe diffusion and diffusion-controlled precipitation processes at high temperatures. During high temperature exposure, technical components like gas-turbine blades, furnaces, or exhaust systems, are operating in corrosive atmospheres. The resulting material-degradation processes are diffusion‐controlled, and corrosive species penetrate into the material leading to the formation of embrittling precipitates. Cellular automata (CA) represent distributed dynamical systems whose structure is particularly well suited to determine the temporal evolution of the system. In this study, it is shown that the model is able to consider diffusion, nucleation and growth aspects, interdiffusion between scales, and high diffusivity paths like grain boundaries. This has been demonstrated by applying CA to (i) nitrogen diffusion, (ii) internal intergranular oxidation of nickel-based alloy, and (iii) interdiffusion of a binary diffusion couple.
Changes in Shrinkage after the Application of Insulation to the Concrete Surface
Authors: Hofírek Radovan , Lang Rostislav , Zich Miloš
Published: March 2018

Concrete shrinkage is affected by the application of hydro insulation or in contrary by the removal of hydro insulation membrane from the concrete elements. Changes in shrinkage are influenced by the age of concrete, the size of the concrete element and the ratio between the different drying surface areas. This paper deals with the evaluation of the long term measurements performed in elements sized 300 x 300 x 300 mm and the application of the acquired knowledge into the modern B4 model.
Strengthening Foundation Slabs below Ground Water Level against Punching Shear
Authors: Nováček Jan , Zich Miloš
Published: March 2018

The paper deals with strengthening structures against punching shear with focus on strengthening of existing concrete foundation slabs. These can be slabs of basements of residential, administrative and other buildings. Also, foundations slabs placed on piles can be considered. This is very specific case of strengthening where only one surface of the structure is accessible. Strengthening is often designed using massive new bearing elements, which are space-demanding. Attention is paid to the development of technology that minimizes the resulting constraints on the surrounding area and is sufficiently effective. Inspiration is strengthening of ceiling flat slabs with additional shear reinforcement. Compared to the ceiling slabs, a larger load must be bear to the foundation structures and therefore the shear reinforcements demand larger dimensions. Mechanical expanded anchors are used for anchoring on the inaccessible side. A significant contribution of mechanical anchoring is demonstrated in the tests results which make possible more efficient design of additional punching reinforcement.
Analysis of Performance of Local Puzzle Sheet in a Joint Made of UHPC
Authors: Jursík Pavel , Vítek Jan L. , Čítek David
Published: March 2018

Nowadays the extraordinary mechanical properties of UHPC can be used for real structures. The exceptionally high bond of reinforcement and UHPC together with significant shortening of lap length are the key features for the simplification of joining of precast elements. The properties of UHPC can be very well used also for providing of subsequent shear connection of composite structures. This paper is focused on analysis of performance of a combined joint where connection of precast elements as well as subsequent composite action between steel and concrete parts of steel-concrete composite structure are carried out in one compact detail. Instead of the traditional headed shear studs there were used local perforated puzzle sheets. More resilient connection of shear sheets to the top flange and a high resistance of UHPC allow for reduction of the extent of shear connectors. In experimental measurements carried out on six beams the behavior of shear connection of conventional monolithic concrete slab with continuous perforated shear sheet and shear connection of precast slab with the joint made of UHPC with local puzzle sheets were compared. During the experiment it has been proven that the performance of the beams with both variants of shear connection is very similar even with the significant reduction of the extent of shear connectors. Numerical analysis which describes the stressing in this detail confirms such behavior.
Results of Short-Term Experiments with Monostrands in Saddles with Small Radii
Authors: Svoboda Adam , Klusáček Ladislav
Published: March 2018

When strengthening existing reinforced concrete structures, we can find many successful applications of post-tensioning. The method of substituted cable ducts is a very convenient especially in the case of strengthening existing reinforced concrete bridges whose load capacity can be increased up to 300 %. Strengthening of structures by post-tensioning is based on active influence of internal forces by prestressing force and radial forces that occur in places of bending the unbonded prestressing tendons. Thus, the forces which acts directly on structure in the anchorage areas and in the locations where the prestressing tendons change their trajectory (in saddles) are considered as the effects of prestressing. Saddles are one of the most important structural details of the additional prestressing system. For the purpose of closer examination of the action of monostrand in steel saddles with different radii of curvature, the methodology of experiment was developed and the concrete test panel in which holes for sensors and substituted cable ducts for monostrand are prepared was created. The concrete test panel enables change of the radius of curvature and was designed for analysis of monostrands in saddles with radii of 600, 1000 and 1500 mm. The aim of short-term experiments with monostrands is to determine suitable application of post-tensioning of existing structures with prestressing tendons in HDPE sheaths in saddles with small radii of curvature.
Long-Term Monitoring of Concrete Building Structure
Authors: Vašátko Radek , Vítek Jan L.
Published: March 2018

Long-term deformations of the concrete are important for determination of behavior of concrete structures. For prediction of the long-term deformations rheological models are used. The models are usually derived from measurements on laboratory specimens. There are only few measurements performed on real structures. The objective of the realized experimental program is to compare predicted values of strains and strains measured on a real structure. Vibrating wire strain gauges have been installed in two columns in underground floors of eight-storey office building. Target of this paper is evaluation of measurement from the initial period (7 to 8 months). Measured values have been compared with results of first calculations and with values measured on laboratory specimens placed at the construction site.
Calculation of Mechanical Fracture Parameters of Chevron Notched Core Based Concrete Specimen: Software CheF
Authors: Svobodova Barbora , Šimonová Hana , Keršner Zbyněk
Published: March 2018

The structural concrete can be also characterized via parameters obtained by evaluation of fracture tests. Therefore, this paper presents software CheF developed in Java programming language, designed for evaluation of three-point bending fracture tests of core based concrete specimens with chevron type notch. The records of fracture tests in form load vs. displacement and load vs. crack mouth opening displacement diagrams are analysed by software CheF to obtain values of selected mechanical fracture parameters: modulus of elasticity E, fracture toughness KIc, and fracture energy GF, determined based on the linear elastic fracture mechanics approach and work-of-fracture method.
Possibilities of Increasing the Durability of Concrete Products by Technologies Based on Surface Hardening
Authors: Hubáček Adam , Osuská Lucia
Published: March 2018

Requirements of the quality of surface have increased recently for vibro-pressed concrete elements. As a consequence, there are new concrete products available with specially treated visual side - surface is coated with an impregnating paint and then hardened by infrared or ultraviolet light.The paper summarizes current knowledge of vibro-pressed concrete elements with surface treated in mentioned way. The focus is on description and effectiveness of individual methods, hardening principles and further possible treatments of surface of concrete aiming at higher durability of concrete. Observed parameters and properties of vibro-pressed concrete elements include resistance of surface to water and chemical de-icers, water absorbing capacity, resistance to wear, slip resistance and reduction of risk of efflorescence.
UHPC Reinforced by Hybrid Fibers and its Resistance to High Temperature Loading
Authors: Rydval Milan , Čítek David , Kolisko Jiří , Pavlík Zbyšek
Published: March 2018

As part of the development and research of UHPC materials, the broad professional public deals mainly with the determination of the basic physical and mechanical parameters, in particular the compressive strength, that is considered as a determining parameter for these cement-based composites. The strength of the composite material is determined under normal laboratory conditions. Fine cement-based composite materials are increasingly used not only for academic purposes but also for practical applications. Therefore, it is necessary to focus on other parameters that determine these new Hi-Tech materials. The mechanical properties of materials at elevated temperatures belong to an area that is not properly defined not only in the Czech Republic but also in the world. Research into the behavior of these composite materials and their thermal loading can provide additional information and basics to expand these building materials such as France, USA, Japan and other countries around the world. In the Czech standards applicable to the design of concrete structures subjected to thermal stress, the values of the reduction coefficient Kc, θ are used only for commonly used dense concrete and also for expanded concrete. It is clear that these values cannot be used for fine-grained composite materials with cement binder reinforced hybrid reinforcements. The aim of the paper is to determine and describe the behavior of these materials in the temperature range of 20 ° C to 1000 ° C for two test modes that affect residual strength and high temperature strength.
Repeatability and Reproducibility of the Static Elastic Modulus of Concrete Measurement
Authors: Misák Petr , Vymazal Tomáš , Kocáb Dalibor , Kucharczyková Barbara
Published: March 2018

In recent years, the static modulus of elasticity is one of the most discussed property of hardened concrete. The aim of this article is to show results of 6 performed experiments focused on test results precision. The measurements were made according to the standards ISO 6784 and ISO 1920-10. More than 20 participants (laboratories) from Europe took part in these experiments. Test results were compared using the statistical methods for interlaboratory comparison. Repeatability and reproducibility, which provide more detailed information about range of expected values of elastic modulus, are the most discussed characteristics in the article.
Detailed Determination of Mechanical Fracture Parameters of Concrete after Fire Experiments
Authors: Šimonová Hana , Trčka Tomáš , Bejček Michal , Rozsypalová Iva , Daněk Petr , Keršner Zbyněk
Published: March 2018

The aim of this paper is to describe the procedure of determining the mechanical fracture parameters of selected concrete specimens taken from panels after the fire experiments. The records (in form load vs displacement diagrams) of three-point bending fracture tests of these specimens with initial stress concentrators was first advanced corrected and subsequently evaluated using the Effective Crack Model and the work-of-fracture method. The increasing temperatures during the fire experiments ranging between 550 to 1000 °C led to a decrease of modulus of elasticity and fracture toughness values and to the increase of fracture energy value. The 2D laser profile scanner was used to estimate the degree of complexity of fracture surfaces; its statistical dependence on the mechanical fracture parameters proved to be moderate – the absolute value of the correlation coefficient was about 0.5°[–].
Effect of Chloride-Induced Steel Corrosion on Working Life of Concrete Structures
Authors: Holly Ivan , Bilčík Juraj
Published: March 2018

The reinforcing steel embedded in concrete is generally protected against corrosion by the high alkalinity (pH = 12.5 to 13.5) of the concrete pore solution. The structural degradation of concrete structures due to reinforcement’s corrosion has an impact on the safety, serviceability and durability of the structure. The corrosion of reinforcements in the construction of a transport infrastructure (especially bridges), parking areas, etc., is primarily initiated by chlorides from de-icing salts. When corrosion is initiated, active corrosion results in a volumetric expansion of the corrosion products around the reinforcing bars against the surrounding concrete. Reinforcement corrosion causes a volume increase due to the oxidation of metallic iron, which is mainly responsible for exerting the expansive radial pressure at the steel–concrete interface and development of hoop tensile stresses in the surrounding concrete. When this tensile stress exceeds the tensile strength of the concrete, cracks are generated. Higher corrosion rates can lead to the cracking and spalling of the concrete cover. Continued corrosion of reinforcement causes a reduction of total loss of bond between concrete and reinforcement.
Crack Resistance of the Self-Stressed Members Reinforced with FRP Bars
Authors: Semianiuk Volha , Tur Viktar V.
Published: March 2018

Fiber reinforced polymer (FRP) bars are widely used in building structures, especially that are exposed to the aggressive environment influence and other special conditions. Nevertheless, due to the low FRP (e.g. glass, basalt, aramid fibers reinforced polymers) bars modulus of elasticity, exceeding crack opening width, as well as deflections can be observed. FRP bars pretensioning is considered as an effective method of its structural performance increasing. Physico-chemical method of the FRP bars pretensioning based on the self-stressing concrete utilizing is an alternative to the mechanical method and in its turn doesn’t need for special devices and anchorage systems as well as qualified personnel. Assessment of the initial stress-strain state obtained during self-stressing concrete expansion stage in the reinforced self-stressed members is presented. Diagram method of the self-stressing parameters verification based on the static loading tests results is presented. Comparison of the initial stress-strain state obtained during concrete expansion stage and predicted by the proposed model, as well as assessment of its influence on the behavior at the static loading stage in cases of the self-stressed reinforced with FRP bars members and traditionally reinforced with steel bars self-stressed members was performed.
Introduction to an Approach to Performing Sustainability Quantification of Concrete Structures
Authors: Teplý Břetislav , Vymazal Tomáš , Rovnaníková Pavla
Published: March 2018

Efficient sustainability management requires the use of tools that enable the quantification, measurement or comparison of material, technological and construction variants. Tools of this kind which have been developed around the world in recent years include various indicators, indexes, etc. Generally, technical, economic, ecological and socio-cultural areas must all be included. Such a tool can be used as a powerful marketing aid and as support for the transition to the “circular economy”. Life Cycle Assessment (LCA) procedures are also used, alongside other approaches. LCA is a method that evaluates the life cycle of a structure from the point of view of its effect on the environment. Processes starting with the mining of mineral resources and including their transport, production and use up to their final processing as waste (recycling) are all taken into account. In addition, consideration is given to energy and raw material costs, and to environmental impact throughout the whole life cycle – e.g. through emissions. The presented contribution focuses on the quantification of sustainability connected with the use of various types of concrete with regard to their resistance against the effect of degrading influences. Sustainability factors are also determined using information regarding service life and “eco-costs”. The aim is to present a suitable methodology which can simplify decision-making concerning the design and choice of concrete mixes from a wider perspective, i.e. not only from the aspects of load-bearing capacity or durability.
Influence of a Shrinkage-Reducing Admixture on the Damage to the Internal Structure of Alkali-Activated Composites during Testing of the Modulus of Elasticity
Authors: Kocáb Dalibor , Bílek Jr. Vlastimil , Topolář Libor , Daněk Petr , Kucharczyková Barbara , Pőssl Petr
Published: March 2018

This article deals with an experimental determination of the static modulus of elasticity in compression on fine-grained composites based on alkali-activated slag. This experiment included an alkali-activated composite without a shrinkage-reducing admixture and the same composite with a shrinkage-reducing admixture. The test specimens were subjected to testing of the dynamic modulus of elasticity using the ultrasonic pulse velocity test and the resonance method as well as of the static modulus of elasticity in compression. The static modulus of elasticity test was accompanied by the measurement of the acoustic activity of the material using the acoustic emission method, whose advantages is the possibility to detect early formation and propagation of cracks in the internal structure of the material. The output of the described experiment is a detailed evaluation of the differences in the behaviour of the tested alkali-activated composites based on the observed values of the modulus of elasticity and the recorded acoustic activity of the material during loading.
The Comparison of Different Recycled Aggregate Types Properties
Authors: Šefflová Magdaléna
Published: March 2018

This paper is focused on properties of recycled aggregate. Three types of recycled aggregate were used for experiment (designation REC A, REC B and REC C) and for comparison natural aggregate (designation NA). The geometrical and physical properties of recycled aggregate were tested. The test results were comparison with natural aggregate. The results confirmed that the quality of the recycled aggregate depends on kind of demolishing process and subsequent recycling process in the recycling plant.
Design of Concrete Pavement in the Považský Chlmec Tunnel
Authors: Mařík Libor , Bůžek Matěj
Published: March 2018

Construction of the Považský Chlmec Tunnel on the D3 Highway in the stretch Žilina (Strážov) – Žilina (Brodno) is being finished and the last structure before installation of the technological equipment has been a concrete pavement and construction works related to design and construction of the pavement. The paper describes not only the issue of road structural layers according to the regulation TP098 Design of Cement Concrete Pavements on Roads, but especially on a specific example of a tunnel already built we demonstrate general particularities of road surfaces in road and highway tunnels. These are, in particular, engineering requirements on the subgrade and possibilities of its drainage, design of joints of the cement concrete pavement in relation to the tunnel lining design, ensuring the necessary long-term roughness of the road surface, design of entries of utility lines (cables, drains) below the road surface, structural details connected with placement of kerbs and channel drains, lay-bys, impacts of use of self-extinguishing road drainage components in the load bearing system of the tunnel lining and other seemingly independent structures, which, however, in the confined tunnel space influence each other substantially. The paper focuses also on construction of the individual road courses with a recommendation for measures to adopt in order to eliminate damage to the tunnel structures completed (in particular, pavements, channel drains and kerbs), coordination of the other works in the tunnel ensuring safety of all workers, logistics (transport of pavers and cement concrete mix) and other apparently tiny details, which result in safe and fast work when placing the road courses in a restricted tunnel space. In the paper, the authors have taken into account requirements of the road engineering segment and also geotechnical requirements and particularities of the tunnel construction and point out the necessity of a multi-professional approach to the design to achieve an optimal solution. Based on their own experience, at the end of the paper, the authors give recommendations on amending the standards and regulations, which in some cases do not allow for construction of road surfaces in tunnels (i.e. deep under the ground).
Applicability of Commercial Software for Bridge Design with Consideration of Seismic Loading Effects
Authors: Havlíček Peter , Šoltész Július
Published: March 2018

The construction of bridges with use of seismic isolation is a less-used concept in Slovakia and the Czech Republic. The concept of seismic isolation of bridges is a way of protecting bridge construction without damaging the pillars and substructure unlike the currently used methodology of consideration and development of plastic joints. When using this concept correctly, it is possible to prevent serious damage of construction and greatly reduce economic losses. Creation of a FEM (Fine Element Method) model, that is capable of correct description of the bridge behavior during a seismic event is often problematic. In this paper, the features of designing and modeling of bridge constructions with use of seismic insulation based on elastomeric bearings are presented. Furthermore, the calculations of stiffness constants required for numerical modeling are presented as well. In this paper are described methods of modeling of seismic isolations in a commonly and commercially available FEM based software. The work also contains a comparison of possibilities as well as limits of these programs. We further present recommendations for correct modeling by use of nonlinear material properties or elastic bonds between elements.
Possibility of Increasing the Load Bearing Capacity of Parapet Bridge Structures
Authors: Svoboda Adam , Klusáček Ladislav
Published: March 2018

Post-tensioning is a suitable, reliable and durable method for strengthening existing reinforced concrete bridge structures. The high efficiency of post-tensioning can be seen on many implemented applications for bridge reconstructions worldwide. There are still several thousands of beam and slab bridges the load capacity of which no longer meets the demanding transport conditions. The oldest reinforced concrete beam bridges, from 1905-1915, are designed according to the Austrian Ministry of Railways Bridge Standard of 1904 when the largest load to be considered was the 18-tonne road steamroller. These bridges are not dimensioned for the currently valid traffic load values. The paper deals with the strengthening of the parapet beam bridges from the period of 1905-1930. These bridges have two main beams pulled over the bridge deck which is supported by cross beams. The cross beams connect the two main beams, forming a half-frame in the transverse direction which provides spatial rigidity of the structure. The spans of these bridges are usually in the range of 15 to 25 m.
Development of Electrically Conductive Composite Sensors with the Addition of Functional Fillers
Authors: Nešpor Bohdan , Nejedlik Martin
Published: March 2018

The paper presents the development results of "smart" pressure-sensitive fibre-cement compositematerials as well as thin-film coating sensors designed to detect disruptions of the base materialstructure. Basic material characteristics of fine-grained and coarse-grained cement matrices wereacquired during the research. The benefits and influence of conductive inorganic components,metallic components in the form of iron fillings and steel wires, and last but not least carbon-basednon-metallic fibrous reinforcement, have been verified. Thin-film epoxy resin coatings were enrichedwith amorphous carbon black, multi-walled carbon nanotubes (MWCNT) and natural micronizedgraphite. The article closely describes the measurement of electrical and electro-mechanical(piezoresistive) properties of conductive fibre-cement composites and thin-film organic coatings in anon-loaded state, during static loading and especially during dynamic ballistic and shock tests on thefall tower. Specific electrical characteristics and the course of change in electric conductivity wasexpressed as electrical resistivity (the real component of the impedance).The performed experiments confirmed excellent electrical conductivity of dense steel-fibrereinforced composites and graphite-doped hybrid fibre reinforced concrete. The coatings showedsignificant and permanent changes in impedance in the order of tens of ohms. The newly developedfibre composites and coating layers change the impedance during destructive and non-destructivedynamic loading tests. The impedance changed not only during failure of the matrix, but also in thecase of indirect impact. Moreover, carbon reinforced concrete with incorporated graphite showedsome piezoresistive properties. These detection materials were intended to be part of a ballistic-resistant monitoring system.
Thermal Analysis of Concrete from Panels Subjected to Fire Experiments
Authors: Šimonová Hana , Rozsypalová Iva , Rovnaníková Pavla , Daněk Petr , Keršner Zbyněk
Published: March 2018

This paper presents the results of the differential thermal analysis of cement matrix samples taken from concrete panels with nominal dimensions of 2300 × 1300 × 150 mm after one-sided exposure to high temperatures. The panels were subjected to maximum nominal temperature loads of 550, 600, 800 and 1000 °C. Concrete was also taken from a reference panel (without temperature loading) and investigated. Five samples with a nominal thickness of 20 mm were taken for thermal analysis. They were cut from the central part of the panels using a diamond blade saw. The thermal analysis covered the effects of temperature load on the concrete to a depth of approximately 100 mm from the heated surface of the panel.
Screw Anchors Used as Post-Installed Shear Reinforcement in Flat Slabs
Authors: Keseli Ondrej , Bilčík Juraj , Holly Ivan
Published: March 2018

More restrictive requirements of new codes, increasing of imposed loads connected with usage change of the existing structures, errors in design process or during execution can lead to necessity of the strengthening of the existing buildings. In paper, the new and modern strengthening system of flat slabs against punching shear using screw anchors is presented. Screw anchors are installed from lower face of the slab into vertically drilled boreholes. After the installation, the screw anchors operate as punching shear reinforcement. The advantages of the system are significant resistance and deformation capacity increment of the flat slab as well as easy and fast installation with no need to drill through the whole slab thickness and access the upper face of the slab. System is suitable for strengthening of office buildings, since removal of the flooring is not needed or in parking garages, where the water resistance is not disturbed by the system. Moreover, paper deals with special problems that are connected with design of the presented strengthening system e.g. considering of load (deformation) level of the slab at the moment of strengthening, performance of the screw anchors in cracked and non-cracked concrete and anchorage conditions improvement of the screw anchors by application of glue or mortar into the borehole prior the screw installation.
In Situ Determination of the Elastic Modulus of Concrete by Means of Ultrasonic Pulse Method
Authors: Cikrle Petr , Kocáb Dalibor , Kucharczyková Barbara , Anton Ondřej
Published: March 2018

The paper deals with the in-situ determination of the modulus of elasticity on the bridge elements using ultrasonic pulse method. This non-destructive test method was chosen for the measurement because of its undisputed advantages that allow the measurement of relatively thick layers of material. For the purpose of the elastic modulus verification the direct measurement was used, in which a pair of transducers (transmitter and receiver) were placed directly opposite to each other. The results of performed in-situ measurements as well as the results of verification tests performed in the laboratory are presented in the paper. The article also discusses the issue of evaluation and interpretation of the results obtained by in-situ measurements using non-destructive test method.
Efficiency Evaluation of Concrete Surface Treatment
Authors: Řepka Jakub , Vlach Tomáš , Laiblová Lenka , Pavlů Tereza , Ženíšek Michal , Hájek Petr
Published: March 2018

This paper presents the simplified method of efficiency evaluation of surface protection products for concrete elements. This evaluation method was designed to consist of as few testing procedures as possible and to use as few specimens as well. Several testing processes most of which were based on the European technical standards were used to compare five commercially available products. Those comparisons served to assess whether the chosen method has sufficient informative value and does not require a disproportionate amount of time and money. The main examined properties were impact on color and reflectivity of the original surface, durability of the coating in extreme weather conditions, wettability of the surface and amount of labor needed for its maintenance. All of these experiments were optimized so that they could be performed on one type of specimen.
Genetics and Genomics of Acute Neurologic Disorders
Authors: Maserati Megan , Alexander Sheila A.
Published: March 2018

Neurologic diseases and injuries are complex and multifactorial, making risk prediction, targeted treatment modalities, and outcome prognostication difficult and elusive. Genetics and genomics have affected clinical practice in many aspects in medicine, particularly cancer treatment. Advancements in knowledge of genetic and genomic variability in neurologic disease and injury are growing rapidly. Although these data are not yet ready for use in clinical practice, research continues to progress and elucidate information that eventually will provide answers to complex neurologic questions and serve as a platform to provide individualized care plans aimed at improving outcomes. This article provides a focused review of relevant literature on genetics, genomics, and common complex neurologic disease and injury likely to be seen in the acute care setting.
Investigating strengths and deficits to increase work engagement: A longitudinal study in the mining industry
Authors: Mphahlele Pule , Els Crizelle , De Beer Leon T. , Mostert Karina
Published: March 2018

Orientation: The motivational process of the Job Demands-Resources (JD-R) model indicates that job resources are the main predictors of work engagement. Previous research has found that the two job resources perceived organisational support (POS) for strengths use and POS for deficit correction are also positively related to work engagement. However, the causal relationships between these variables have not been investigated longitudinally.Research purpose: To determine if POS for strengths use and POS for deficit correction are significant predictors of work engagement over time.Motivation for the study: In the literature, empirical evidence on the longitudinal relationships between work engagement and specific job resources, namely POS for strengths use and POS for deficit correction, is limited.Research design, approach and method: A longitudinal design was employed in this study. The first wave elicited a total of 376 responses, while the second wave had a total sample size of 79. A web-based survey was used to measure the constructs and to gather data at both points in time. Structural equation modelling was used to investigate the hypotheses.Main findings: The results indicated that both POS for strengths use and POS for deficit correction are positively related to work engagement in the short term. However, only POS for deficit correction significantly predicted work engagement over time.Practical and managerial implications: The results provide valuable insights to organisations by providing knowledge regarding which approach influences work engagement levels of their employees in the short and long term.Contribution or value-add: The study contributes to the limited research on what job resources predict work engagement over time.
Overview of Japanese Language in Upper Secondary Education and School Curriculum in Romania
Authors: LUNGU Mariana
Published: March 2018

In this paper, I focus my attention on the problem of teaching Japanese as part of compulsory subjects in an upper secondary education to pupils aged between 15 to 19. This article starts out with a brief overview of the Romanian education system and the current state of Japanese teaching in the upper secondary education. As compared to other educational curricula, the Romanian education system focuses on competency-based curriculum emphasizing the applicability of knowledge and the development of competences in an integrated and inter-disciplinary approach. The Japanese Language is part of that curricular area named as Language and Communication. In the Romanian educational system, the process of teaching the Japanese language starts from lower secondary school and continues to upper secondary and then to university level. In the lower secondary school, pupils study the Japanese Language as an elective subject, while in the upper secondary school, they learn Japanese as a mandatory subject of the core curriculum and as an elective one of school-based curriculum. Next, attention is paid to outline the current situation of teaching Japanese in the upper-secondary education system, providing details of our curricula, types of subjects, and specific features of Japanese classes. Forms of Japanese language education vary greatly, as well as their target students and objectives. However, the focus of all is a balanced education in the four language skills: reading, writing, listening and speaking. In addition to the Japanese language study, Japanese syllabi provide cultural and general education to learn the properties in Japanese Society and about contemporary culture.
Teaching of the Japanese and Chinese Language in Extracurricular Courses for Children, Adolescents and Adults in Slovenia
Authors: FEHER MALAČIČ Karmen
Published: March 2018

The presentation includes a brief history of Japanese and Chinese teaching and learning at Pionirski dom and the current trends. On the one hand, it explores the reasons why so many youngsters decide to learn Japanese or Chinese, what is their main interest and what is they want to achieve. On the other hand, it tackles the points of view of teachers of the Japanese and Chinese language towards language teaching and the issues raised while teaching. Pionirski dom is probably the only institution in Slovenia with so many young learners and teenagers enrolled in Japanese courses and with a decade of experience in the area. Much attention is, therefore, put on quality programmes and the choice of suitable teachers.
Teaching Chinese at the University Level in Serbia: Examples of Good Practices and Possibilities for Further Developments
Authors: JOVANOVIĆ Ana M.
Published: March 2018

The aim of this paper is to give a short overview of the current situation in the field of Chinese language teaching in Serbian formal education with a special emphasis on teaching Chinese at the university level. The Faculty of Philology of the University of Belgrade is one of the institutions with the longest tradition of teaching Chinese language as a major in the whole Balkan region, and in Serbia it is the only one where students can study Chinese at both the undergraduate and the graduate level. An elaborate curriculum, which includes courses on language, literature and culture, enables their students to gain a thorough insight in many aspects of ancient and modern China. Accordingly a large section of this paper is dedicated to presenting the teaching practices used at that institution, together with examples of some practical in-class methods. The paper also offers a short introduction to one private university in Serbia where Chinese language teaching has been carried out successfully. Finally it offers some ideas how teaching Chinese as a foreign language can be improved at all levels of study worldwide.
Teaching Japanese Language in Tertiary and Secondary Education: State and Private Institutions in Romania
Authors: DRAGAN Angela
Published: March 2018

In Romania, Japanese language, literature and culture are taught at university level in two private universities and two state universities. Japanese departments are part of either a Faculty of Letters or a Faculty of Languages and Literatures. Students have to choose another language to study, in addition to Japanese. This gives them a dual major / dual specialization. A large number of graduates decide on pursuing a teaching career in one of their specializations. My paper looks at the way in which university provides an educational background for teachers at lower and upper education. It also looks into the way it shapes secondary education through its curriculum. This refers to compulsory education in an integrated national system of education. But, in the last ten years, this perspective has broadened. Language schools, which are not part of this integrated system, have appeared. Some of them teach exclusively Japanese language and Japanese culture classes. In the beginning, the students were mainly adults, age 18+ but in the last several years, more children have started to be interested in attending classes in these language schools. My paper also discusses this new perspective. A questionnaire and its results will also be presented on this topic. It will show not only the increasing number of young learners but also, their very young age, which goes as far as primary school. This tendency, in studying Japanese as a foreign language, could provide a preview into its development at the secondary level.