bluuebunny/crossref_metadata_2025 huggingface dataset:
Dissecting metabolism using zebrafish models of disease
Authors: Salmi Talhah M. , Tan Vicky W. T. , Cox Andrew G.
Published: January 2019

Zebrafish (Danio rerio) are becoming an increasingly powerful model organism to study the role of metabolism in disease. Since its inception, the zebrafish model has relied on unique attributes such as the transparency of embryos, high fecundity and conservation with higher vertebrates, to perform phenotype-driven chemical and genetic screens. In this review, we describe how zebrafish have been used to reveal novel mechanisms by which metabolism regulates embryonic development, obesity, fatty liver disease and cancer. In addition, we will highlight how new approaches in advanced microscopy, transcriptomics and metabolomics using zebrafish as a model system have yielded fundamental insights into the mechanistic underpinnings of disease.
Low‐power contactless LC‐tank based respiratory sensor
Authors: Scheiner B. , Schellenberger S. , Shi K. , Heusinger E. , Michler F. , Lurz F. , Weigel R. , Koelpin A.
Published: January 2019

In this Letter, a novel approach for contactless, low‐cost and low‐power respiratory sensing is presented, which is based on a commercial LC tank. This sensor is able to measure the variation of losses of induced eddy currents during one respiration period. The developed sensor system can be used in multiple different application fields where low‐cost and low‐power respiratory sensing is necessary. Examples for that can be infant or patient beds where vital parameters have to be monitored or in other fields where contactless presence check is desired. At first, the theory of operation and requirements for the respiratory sensing applications are explained which is followed by the system design and measurement results.
A distant OB association around RAFGL 5475
Authors: Comerón F. , Djupvik A. A. , Torra J. , Schneider N. , Pasquali A.
Published: January 2019

Context. Observations of the galactic disk at mid-infrared and longer wavelengths reveal a wealth of structures indicating the existence of complexes of recent massive star formation. However, little or nothing is known about the stellar component of those complexes.

Aims. We have carried out observations aiming at the identification of early-type stars in the direction of the bright infrared source RAFGL 5475, around which several interstellar medium structures usually associated with the presence of massive stars have been identified. Our observations have the potential of revealing the suspected but thus far unknown stellar component of the region around RAFGL 5475.

Methods. We have carried out near-infrared imaging observations (JHKs bands) designed to reveal the presence of early-type stars based on their positions in color–color and color–magnitude diagrams centered on the location of RAFGL 5475. We took into account the possibility that candidates found might belong to a foreground population physically related either to M 16 or M 17, two giant HII regions lying midway between the Sun and RAFGL 5475.

Results. The near-infrared color–color diagram shows clear evidence for the presence of a moderately obscured population of early-type stars in the region imaged. By studying the distribution of extinction in their direction and basic characteristics of the interstellar medium we show that these new early-type stars are most likely associated with RAFGL 5475.

Conclusions. By investigating the possible existence of massive early-type stars in the direction of RAFGL 5475 we have discovered the existence of a new OB association. A very preliminary assessment of its contents suggests the presence of several O-type stars, some of them likely to be associated with structures in the interstellar medium. The new association is located at 4 kpc from the Sun in the Scutum-Centaurus arm.
G.A.S.
Authors: Cousin M. , Buat V. , Lagache G. , Bethermin M.
Published: January 2019

Context. Dust is a crucial component of the interstellar medium of galaxies. The presence of dust strongly affects the light produced by stars within a galaxy. As these photons are our main information vector to explore the stellar mass assembly and therefore understand a galaxy’s evolution, modeling the luminous properties of galaxies and taking into account the impact of the dust is a fundamental challenge for semi-analytical models.

Aims. We present the complete prescription of dust attenuation implemented in the new semi-analytical model called G.A.S. This model is based on a two-phase medium originating from a physically motivated turbulent model of gas structuring (G.A.S. Paper I).

Methods. Dust impact is treated by taking into account three dust components: polycyclic aromatic hydrocarbons, very small grains and big grains. All three components evolve in both a diffuse and a fragmented/dense gas phase. Each phase has its own stars, dust content and geometry. Dust content evolves according to the metallicity of it associated phase.

Results. The G.A.S. model is used to predict both the ultraviolet (UV) and the infrared (IR) luminosity functions from z = 9.0 to z = 0.1. Our two-phase ISM prescription catches the evolution of UV and IR luminosity functions very well. We note a small overproduction of the IR luminosity at low redshift (z <  0.5). We also focus on the infrared-excess (IRX) and explore its dependency with the stellar mass, UV slope, stellar age, metallicity and slope of the attenuation curves. Our model predicts large scatters for relations based on IRX, especially for the IRX–β relation. Our analysis reveals that the slope of the attenuation curve is more driven by absolute attenuation in the far-ultraviolet (FUV) band than by disk inclination. We confirm that the age of the stellar population and the slope of the attenuation curve can both shift galaxies below the fiducial star-birth relation in the IRX–β diagram. Main results presented in this paper (e.g., luminosity functions) and in the two other associated G.A.S. papers are stored and available in the GALAKSIENN library through the ZENODO platform.
Rainfall variability in Malay Peninsula region of Southeast Asia using gridded data
Authors: Singh Vishal , Qin Xiaosheng
Published: January 2019

Southeast Asia is recognized as a climate-change vulnerable region as it has been significantly affected by many extreme events in the past. This study carried out a rainfall analysis over the Malay Peninsula region of Southeast Asia utilizing historical (1981-2007) gridded rainfall datasets (0.5°×0.5°). The rainfall variability was analyzed in an intra-decadal time series duration. The uncertainty involved in all datasets was also checked based on the comparison of multiple global rainfall datasets. Rainfall gap filling analysis was conducted for producing more accurate rainfall time series after testing multiple mathematical functions. Frequency-based rainfall extreme indices such as Dry Days and Wet days are generated to assess the rainfall variability over the study area. Our results revealed a notable variation existed in the rainfalls over Malay Peninsula as per the long historical duration (1981-2007).
Nationwide Assessment of Urban Surface Water Environment Status in China
Authors: Gao Hongjie , Yuan Peng , Liu Ruixia , Han Lu , Song Yonghui
Published: January 2019

In this study, the assessment of nationwide urban water environment status was conducted based upon a method of integrating both 70% of objective water quality and 30% of standard compliance percent compared with national standard limit of GB3838-2002 for Class III. The impact factors on urban water environment status were discussed. The results showed that the status of urban water environment could be graded into 5 types in China. The population density, water resources, urbanized areas and so on were key impact factors on water environment. The study found that population density and urban built-up area had significantly negative effect on urban water environment status, and there was positive relationship between per capita water resources and urban water environment status. The results would provide the guidance for effective governance and management of urban water environment at national level.
Prospects of development of aquaculture in Russia and its regions
Authors: Kalinina Lyudmila , Zelenskaya Inga , Trufanova Sofya , Kalinin Nicolay
Published: January 2019

The state program “Development of aquaculture (commercial fish farming) in the Russian Federation for 2015-2020” (hereinafter referred to as the State Program) determines the main directions for the development of the fisheries complex and its financial support. However, the current program does not sufficiently elaborate the forms of state support for this sphere of agricultural production, which would contribute to the accelerated development of the industry. It should also be noted that the existing potential of aquaculture in Russia is not fully utilized. The Institute of Economics of the Irkutsk State Agrarian University named after A.A. Ezhevsky, in collaboration with the Ministry of Agriculture of the Irkutsk Region, assessed the fulfillment of tasks of the State Program, identified factors hindering the development of aquaculture in Russia and its regions, and developed recommendations for improving the forms of state support for economic entities in the industry.
Challenges to the sustainable use of water resources in the Ili River basin of Central Asia
Authors: Nurtazin Sabir , Thevs Niels , Iklasov Margulan , Graham Norman , Salmurzauli Ruslan , Pueppke Steven
Published: January 2019

Water is a scarce resource in Central Asia, and many catchments span international boundaries, among them that of the Ili River, which is shared by China and Kazakhstan. Since 1970, the natural hydrological regime of the Ili River, both absolute flow rates and cycles, has changed due to construction of reservoirs such as that at Kapchagai, as well as natural climatic cycles and the growth of water consumption in the basin. Using data from Kazhydromet, we calculated that flow rates below Kapchagai dam averaged 468 m3/sec before construction of the dam, 366 m3/sec while the reservoir was being filled, and 489 m3/sec between 1988 and 2013. The dam has profoundly altered the annual cycle of flows in the river, with reductions in the summer and increases in the winter, when water is released to produce hydropower. The effects of these changes are being heightened by China’s increasing diversion of the river’s water. The sustainable use of decreasing water resources to conserve the biodiversity of the Ili-Balkhash basin’s ecosystems mandates a solution to the water allocation challenge between China and Kazakhstan. This will require a basin-wide approach that includes modernization of water distribution systems and careful consideration to relative priority needs for food, hydropower, and communal uses in both countries.
Experimental study of open-channel flow with partial double-layered vegetation
Authors: Tang Xiaonan , Rahimi Hamidrez , Singh Prateek , Wei Zishun , Wang Yuxuan , Zhao Yufan , Lu Qiangshuai
Published: January 2019

Many rivers and wetlands have vegetation. The effect of riparian vegetation on ecological and flow process in channels has become increasingly important in river flood risk and aquatic environmental management. Most previous studies have been done on the flow structure of vegetation of the same height which is not realistic in natural rivers. There are only a few studies on flows with a mixing array of short and tall vegetation under either submerged or emergent flow condition. This paper is to undertake a novel experimental study on a flow with double-layered vegetation under submerged and emergent conditions, which often occur in most rivers. Two different heights of dowels, 10 cm and 20 cm, were used in the water flume to represent the short and tall vegetation respectively, and they were allocated on one side of the flume. Experiments in two flow depths were undertaken to represent different submergence ratios of vegetation, and velocities at various locations were measured by Acoustic Doppler Velocimetry (ADV) and propeller velocimetry. Experimental results show that the velocity profile is almost uniform within the depth of short vegetation in different configurations. The velocity starts to increase in the region near the edge of short vegetation, and then followed by a rapid increase through the height of tall vegetation to the free surface. Meanwhile, a strange shear layer exists laterally between vegetation and non-vegetation, showing that the vegetation significantly reduces the velocity of flow.
The Study on the Relationship between the Environmental and Financial Performances of Corporates Which Have Adopting the System of Environmental Accounting in Taiwan
Authors: Huang Wei-Lun , Fu Yan-Kai
Published: January 2019

The purpose of this paper is to study the relationship between the environmental and financial performance of Corporates. For the environmental awareness of people, the social responsibility of companies and the environmental policies and laws of government, more and more companies would adopt the system of environmental accounting, and then they would disclosure their environmental performances. From the review of literature and the statistics results on the financial and environmental performances of listed companies which had adopted the environmental accounting system in Taiwan, the results are: 1.the adopting on the system of environmental accounting might make the corporations’ financial performances worse, but not significantly make corporations’ environmental performances better. 2. There should be a positive relationship between the environmental performance and financial performance of companies.
Rich water flow, live water revitalizes the countryside–Rural water resources utilization design under the rural revitalization strategy
Authors: Deng DeXiang , Liu KaiGe , Zhou Xi
Published: January 2019

Revitalizing the countryside should first develop water resources. The rational use of rural water resources will greatly enhance the endogenous power of rural revitalization, help to achieve the 1strategic rural revitalization goal of rich water and longevity, and promote the sustainable revitalization of rural areas in China.
Geotechnical properties of sewage sludge solidified with Sulphoaluminate cement
Authors: Fan Xihui , Xu Haoqing , Wang Shengwei , Shu Shi , Lin Naixi , Qian Yongjin
Published: January 2019

The geotechnical properties of sewage sludge solidified with sulphoaluminate cement are presented. The sludge has a high water content and organic matter which is not easy to disposal. After Solidification/Stabilization (S/S), landfill disposal of sewage sludge is widely adopted in China. However, there is little research focused on the geotechnical properties of sewage sludge after S/S treatment and the impact on the landfill site is also difficult to be evaluated. To solve this problem, this paper is aimed to evaluate the basic mechanics properties of solidified materials by means of Atterberg limit, triaxial test, consolidation test and permeability test. The result showed that the strength and the hydraulic conductivity of the modified sludge was close to that of the high organic soil. By adding suitable additives, modified sludge could not only satisfy the requirement of being landfilled but also be utilized as a construction material.
Influence of the strip-shaped air-out slits’ width in the fully mechanized working face under wallattached swirling ventilation condition
Authors: Li Yongjun , Wang Pengfei , Liu Ronghua , Han Han , Tan Xuanhao , Jiang Yidan
Published: January 2019

For the purpose of mastering the influence of the strip-shaped air-out slits’ width in the fully mechanized working face under wallattached swirling ventilation condition, By using fluent software, numerical simulation of airflow field and dust diffusion in fully mechanized working face under different strip-shaped air-out slits’ width conditions was carried out. The results show that the wall-attached swirling ventilation can effectively control the dust diffusion in the fully mechanized working face, improve the dust collecting effect of the bag precipitator fan, and reduce the particle mass concentration at the driver and the rear of the tunnel; Increasing the air volume of the strip-shaped airout slits can improve the control effect of the swirling air curtain on the dust, appropriate air volume can make the swirling air curtain control the dusty airflow and push it to the end of the heading surface to control, block and propel the dust; When the width of the strip-shaped air-out slits is 0.06 m, the dust collecting effect of the exhaust air cylinder on the dust and the effect of the wall-attached swirling on the plugging of the dust are best.
Experimental study on atomization characteristics of two common spiral channel pressure nozzles
Authors: Han Han , Wang Pengfei , Liu Ronghua , Li Yongjun , Wang Jan , Jiang Yidan
Published: January 2019

Spiral channel pressure nozzles are commonly used pressure nozzles in practical workplaces. In this paper, two kinds of spiral channel type pressure nozzles, namely, spiral hole type and spiral non-porous type, the atomization characteristics and dust reduction efficiency under different spray pressures are discussed and compared. Based on the experimental method, based on the self-designed spray dust-reducing roadway experimental platform, the macro-atomization characteristics of the two nozzles, namely the flow rate, the atomization angle, the range, and the droplet size, were measured. The following conclusions were drawn: (1) The flow rates of both nozzles increase with increasing spray pressure, and the flow coefficient of the spiral non-porous nozzle is small. (2) The change of the atomization angle of the two nozzles first increases and then decreases with the increase of the spray pressure, and the atomization angle of the spiral non-porous nozzle is larger. At the same time, the range of the two nozzles gradually increases as the spray pressure increases, and the range of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle. (3) When the spray pressure is gradually increased, the droplet size of the two nozzles selected in the experiment is gradually reduced, and the droplet size of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle before 5 MPa, and then gradually Become smaller. The main reason why the droplet size decreases with the increase of the spray pressure is that the increase of the spray pressure leads to an increase in the spray speed of the water droplets, so that the water droplets are completely split when they are ejected from the nozzle, resulting in a smaller droplet size. In summary, when the spray pressure required in the actual working environment is low, the use of a spiral non-porous nozzle is more conducive to dust reduction.
The Relationship between China’s Financial Industry Performance and Energy Elimination
Authors: Wu Jun-Qi , Chou Li-Chen
Published: January 2019

Taking the provinces, autonomous regions and cities in mainland China as the research objects, this paper collects and collates the data of production, input and energy consumption of the financial industry from 2009 to 2014, and analyzes the production efficiency of each region. The empirical results show that the production efficiency of all prefecture-level cities is 0.782. If analysed on region basis, the average production efficiency of prefecture-level cities is the highest in the eastern provinces, followed by the central provinces and the lowest in the western provinces. If analysed on annual basis, the distribution of production efficiency shows a trend of decline during 2009-2010 and increase after 2012.
Glass transition effect of adhesive in timber beams strengthened with CFRP overlays
Authors: Krzywon Rafał , Brol Janusz
Published: January 2019

There are situations when timber structure requires strengthening caused by environmental deterioration or changes in load conditions. Its mechanical performance can be increased by use of externally bonded high strength fibre reinforced composite (FRP). The place of application increases the sensitivity of this technique to environmental effects, including heating by the sun rays. Surface temperature can exceed 70 °C, while usually as safe is considered 45 °C. Paper describes the tests of timber beams strengthened with two types of composites: unidirectional CFRP sheet and CFRP strip. They were heated at various temperature ranges and tested in bending. Out of the nine tested beams, only one heated to 95 °C was not damaged by the delamination of the composite overlay, remaining beams have not been destroyed due to achieved deflection exceeding the press cylinder range or were failed due to rupture of carbon fibres. The influence of the temperature was better recognizable in differences of deflections and strains caused by the creep in the adhesive layer weakened by temperature. It should also be emphasized that got results are much better than for commonly tested reinforced concrete beams, where delamination caused failure slightly above 65 °C.
Analysis of changes in the system of identification and classification of soils
Authors: Sulewska Maria Jolanta
Published: January 2019

The objective of the article is to analyse the proposed changes in the European and international principles of the system of identification and classification of soils, included in Final Draft International Standards: ISO/FDIS 14688-1:2017 and ISO/FDIS 14688-2:2017, which will probably be introduced in 2018 or 2019.
Assessment of Gilsonite and Trinidad Epuré natural asphaltmodified binders ability to relaxation at low temperature
Authors: Marcin Bilski , Mieczyslaw Słowik
Published: January 2019

The paper presents the results of the tests conducted on asphalt binders modified with additives of natural Gilsonite and Trinidad Epuré asphalts, as well as the 20/30, 35/50 and 50/70 penetration grade bitumens by use of an original observation method of the relaxation phenomenon in low temperature. In the tests the authors used a ductilometer equipped with a dynamometer and a bath filled up with a liquid with the temperature of-16°C. Relaxation of the asphalt binder was observed in the period of 20 minutes in the conditions of constant deformation of the sample caused by its prior extension with the constant speed of 1 mm/min. The value of the normal stress occurring in the asphalt binder is calculated on the basis of the measured value of the normal (tensile) force. It has been noted that asphalt binders with higher penetration values are characterised by a better relaxation ability at low temperature, that is relaxation takes place faster and has higher values of sample stress reduction in the domain of time, at constant strain. With approximate penetration values (the maximum penetration difference at 25°C amounting to ±2 mm/10), modified binders comprising Gilsonite are characterised by better relaxation abilities in comparison to binders containing the Trinidad Epuré additive.
Experimental and numerical distribution of pressure on the abutment with backfill from tyre bales
Authors: Duda Aleksander , Siwowski Tomasz
Published: January 2019

This article describes the tests of the pressure distribution on bridge abutment generated by the backfill made of the recycled car tyres compressed in the form of bales with interfaces of medium sands and a buffer layer with tyre shreds. Backfill pressure distribution was measuring continuously over a period of three months using a pressure sensors. Static and dynamic load tests of abutment were conducted and cyclic horizontal displacements of the abutment wall, as a simulation of thermal elongation / shortening of the bridge span were also performed. The results of pressure field measurements were compared with results of numerical analysis performed using the GEO5 program basing on finite element method. Compatibility results of field measurements and numerical analysis was pretty good, and the maximum difference was about 25%. Based on field measurements and numerical analysis, a 2÷4 times reduction of pressure on bridge abutment was found, if the tyre bales had been used, compared to conventional backfilling of medium sand.
High temperature properties of modified bituminous binders produced in Poland
Authors: Radziszewski Piotr , Sarnowski Michał , Pokorski Piotr , Kowalski Karol J. , Król Jan
Published: January 2019

Bitumen used for the construction of road pavements should exhibit adequate resistance to loads at high operating temperatures. An effective method of improving the properties of bitumen is their modification. To evaluate the high-temperature properties of bitumen, standard consistency tests and advanced rheological tests under dynamic load are conducted. The main purpose of the article is to assess the high temperature properties of modified binders produced by two major Polish producers. The assessment was based on the tests results of modified binders in the range of the standard softening point temperature test and tests in the dynamic shear rheometer (DSR) according to the requirements of Strategic Highway Research Program (SHRP) and Multiple Stress Creep Recovery Test (MSCR). It has been shown that due to the highest operating temperatures of road pavements in Poland, produced bituminous binders meet the requirements of resistance to permanent deformation with a great reserve.
The statistical impact of experimental result scatter of asphalt mixtures on their numerical modelling
Authors: Szydłowski Cezary , Górski Jarosław , Stienss Marcin , Smakosz Łukasz
Published: January 2019

The paper presents selected test results of asphalt mixture conducted in low temperatures. The obtained parameters are highly diverse. It concerns ultimate breaking loads, stiffness parameters related to Young's modulus but also the fracture course. Statistical analysis upon the results makes it possible to relevantly estimate the material-defining parameter values. Such a random approach leads to the mean values of breaking and fracture-triggering loads, dealing with their dispersion too. The estimated parameters allow to form appropriate numerical models of asphalt mixture specimens. This type of analysis supports the laboratory tests. The paper presents the authors' simplified model considering non-uniform material features. The results reflect the scatter of real laboratory test outcomes. In order to do so an algorithm to calibrate the numerical model parameters was created.
The influence of alkali-resistant glass fibres on properties of fine-aggregate concretes
Authors: Domagała Lucyna , Bizoń-Żabińska Ewelina , Kurzyniec Kamil
Published: January 2019

The aim of this paper is to assess the effect of modification of fine-aggregate concrete properties with zirconia alkali-resistant glass fibres. Three types of fine-aggregate composites were subject to tests: normal-weight concretes made of natural sand, non-foamed and foamed lightweight concretes made of expanded glass aggregate. The concretes were modified with the glass fibres mainly in quantities ranged from 1.0 to 5.0 kg/m3. Even such low contents resulted in the increase of both flexural and compressive strength, by up to 45 % and 26 %, respectively. In the case of normal-weight fine-aggregate concretes the applied glass fibres turned out to be especially effective in improvement of the properties in early ages. At the age of 28 days both types of concretes revealed similar percentage strength increase. In comparison to HP 12 mm the application of longer fibres (HP 24 mm) led to slightly higher results of flexural strength tests. On the other hand, the shorter fibres were definitely more effective in the improvement of compressive strength due to their greater number and more uniform dispersion in concrete volume. The used contents of alkali-resistant glass fibres did affect neither density nor water absorption of the hardened concretes.
Impact of lowered curing temperature on the compressive strength of polymer-cement repair mortars
Authors: Wojnowski Damian , Francke Barbara
Published: January 2019

This article discusses the results of tests regarding mechanical properties of polymer-cement repair mortars which were cured at a lowered temperature. The assessment was based on compressive strength tests of three PCC repair mortars available on the market. The tests were performed on samples cured at a temperature of 21°C and 8°C and following designed variable-temperature cycles. The tests showed a negative impact of lowered temperature present during curing of concrete repair mortars on these mortars’ compressive strength. Repairing concrete structures during lowered temperatures may cause a drop in parameters considerably lowering the product’s class. Extending the cure time for mortars applied and cured at low temperatures will cause these parameters to increase, but will not always allow to achieve values equal to those of samples cured in laboratory conditions.
Decision Support in the Process of Choosing a Residential Building Technology
Authors: Gicala Magdalena , Sagan Joanna , Sobotka Anna
Published: January 2019

The choice of construction technology depends on many factors, which are now increasingly determined by the developing concept of sustainability. Decisions made at the stage of building planning and design should take into account not only the technical but also environmental, social and economic efficiency of the building throughout its life cycle. The aim of the article is the development of the methodology of supporting the technology selection process on the basis of research results, experience and opinions of building users. The DSS (decision support system) developed based on this concept may facilitate potential investors selection of technologies and support designers and constructors to improve their solutions.
Cost risk of construction of small hydroelectric power plants
Authors: Górecki Jarosław , Płoszaj Ewa
Published: January 2019

The growing demand for electricity forces the humanity to find the most economical methods of its production. Functioning without electricity in today's world deprives human from the possibility of a free existence, and even completely prevents it because of the technicisation of society. Growing awareness of acquiring "clean" environmentally-friendly energy from renewable sources contributes to the successive development of this sector of the economy. The purpose of the article was to analyse the risk of construction costs for small hydroelectric power plants along with an indication of the location and needs of a small hydroelectric power plant in Poland. The subject of the study was a small hydroelectric power plant producing electricity, using a turbine to convert the kinetic energy of water into mechanical energy. Aiming at illustrating the benefits of the discussed investment based on the estimation of construction costs and, as a result, financial results, a specific case of a small hydroelectric power plant located in the region of Kujawsko-Pomorskie [Kuyavian-Pomeranian Viovodeship] in central Poland was analysed. The intended research objective was achieved using industry literature, magazines as well as technical knowledge of persons holding building qualifications (including hydro-technical construction) and materials made available by two Bydgoszcz companies specializing in the implementation of small hydroelectric power plants. TheCOMAR- Jarek Górecki®algorithm, which operates in the industry as the author's concept of calculating the variation of financial outlays incurred for the implementation of investment and construction projects, was used to analyse the risk of costs of a construction project.
Influence of surface based cohesive parameters on static performance of concrete composite T-shaped beams
Authors: Jabłoński Łukasz , Halicka Anna
Published: January 2019

The study presented constitutes the next step of authors’ investigations on the concrete composite T-shaped beams. The comparison of the failure modes and crack patterns of numerical models and beams tested was performed previously. In this paper, analyses concentrate on determination the proper values of cohesive surface parameters ensuring the high conformity of deformation and strains of the numerical model to the experimental results. In the particular series of beams the interfaces between concrete parts are varied as follows: reinforced joint with normal and tangential interactions only (BZ/S2/A), non-reinforced joint with adhesion (BZ/P), and reinforced joint with adhesion (BZ/P+S). Material properties used in numerical model are based on obtained in the laboratory ones. Furthermore, the ‘traction–separation’ law in the ABAQUS software defining the cohesion surface is used and analysis of the cohesive parameters response to interface roughness is carried out. The results show a strong dependence between the cohesion surface parameters and the response of the composite beam. A very good convergence of the numerical model with the experimental results in terms of ‘force-displacement’ relationship is achieved. Finally the parameters defined in the ABAQUS are determined, which have a key impact on the beams response.
Analytical and numerical research of equivalent stabilizing force of stiffened truss chords
Authors: Biegus Antoni , Czepiżak Dariusz
Published: January 2019

The aim of this paper is research of the equivalent stabilizing forces of the braced top flange of the truss. The study takes into account the initial bow imperfection e0 of the braced top flange and the im-perfection consisting in a twist of the roof girder’s principal plane by angle ϕ0(x). Moreover, axial force N3(x) in the top flange of the truss is assumed to be longitudinally parabolically variable. The values of the axial forces is: Nsupp in the support zone of the truss and Nspan in the central zone of truss. As part of this study parametric analyses of the equivalent stabilizing forces and the stress of the bracings depending on axial forces Nsupp and Nspan in the braced member were carried out. The results are compared with the results of numerical analyses of 3D models taking the geometric nonlinearity of the structure into account.
Influence of geometrical imperfection on critical temperature evaluation for steel corrugated arch sheets exposed to fire
Authors: Maślak Mariusz , Pazdanowski Michał , Suchodoła Maciej
Published: January 2019

The critical temperature for an arched corrugated steel sheet exposed to fully developed fire is determined in this paper. The analysis is performed on 3D numerical model developed within the ANSYS computational environment with parameters calibrated experimentally on an experiment performed for persistent design scenario. During the simulations performed the self-supporting steel sheet with an assumed initial shape imperfection is at first loaded with static load, up to a predetermined level of material effort, and subsequently evenly heated until the capability to safely resist the applied load is completely exhausted. Because of the nonlinearity of the analysis having several sources, the location of the limit point on the equilibrium path determined during calculations represents the temperature sought. Three imperfection patterns, denoted as A, B and C are considered. In the case A the imperfection has the shape and magnitude measured in situ, selected as representative for a set of 10 steel sheets of the same type. In the case B the imperfection is a substitute one with size analogous to that assumed in the case A, but with a different shape, corresponding to the first antisymmetric buckling mode identified in conventional Local Buckling Analysis (LBA). In the case C the shape of imperfection B has been kept, but the positive and negative deviation from the perfect circular shape have been increased twofold.
The influence of the torsional restraint of crane column brackets on their critical load capacity
Authors: Redecki Michał , Gosowski Bronisław
Published: January 2019

The paper presents the results of numerical parametric studies conducted on laterally restrained steel I-columns with a single stepped asymmetric change in their cross-section. Such elements are used as a part of the outermost columns in the transversal system of steel halls with cranes. The columns are usually braced along their length with wall girts, which in a properly structured hall system have a significant effect on the columns’ load bearing capacity and determine their axis of rotation. The main aim of the presented studies is to determine the impact of parameters, such as longitudinal load distribution on the upper and lower segment of the column, the number of pointed lateral bracings and their distance to a column's external flange, and also the application of torsional restraint on the critical load capacity. Results are presented as surfaces or contour maps, in which the ordinates represent the critical loads with regards to the analysed parameters. The paper ends with practical conclusions.
Parametric analysis of some tensegrity structures
Authors: Gilewski Wojciech , Kłosowska Joanna , Obara Paulina
Published: January 2019

The objective of the paper are tensegrity structures and a possibility to control their properties such as a stiffness and a natural frequency, by the level of self-stress. Basic tensegrity modules and towers and plates built of these modules are considered. In each example mechanisms and self-stress states are identified using the singular value decomposition of compatibility matrix method. Parametric analyses of the effect of the self-stress state on the static and dynamic properties of structures are carried out. Analyses are performed using the second order theory (in Mathematica environment) and the third order theory (in Sofistik program).
Size effect in concrete beams under bending – influence of the boundary layer and the numerical description of cracks
Authors: Marzec Ireneusz , Bobiński Jerzy
Published: January 2019

In the paper the size effect phenomenon in concrete is analysed. The results of numerical simulations of using FEM on geometrically similar un-notched and notched concrete beams under bending are presented. Concrete beams of four different sizes and five different notch heights under three-point bending test were simulated. In total 18 beams were analysed. Two approaches were used to describe cracks in concrete. First, eXtended Finite Element Method (XFEM) describing cracks as discrete cohesive ones with bilinear softening was chosen. Alternatively, an elasto-plastic constitutive law with Rankine criterion, associated flow rule and bilinear softening was defined. In order to ensure mesh-independent FE results, a non-local theory in an integral format as a regularisation technique was applied in the softening regime. In both approaches the influence of the decrease of the material parameters (mainly fracture energy) in the boundary layer on obtained maximum loads was studied. Additionally the influence of the averaging method in non-local plasticity was also examined. Obtained results were compared with experimental outcomes available in literature.
Geotechnical design of railway embankments – requirements and challenges
Authors: Bogusz Witold , Godlewski Tomasz
Published: January 2019

Intensive development of railway infrastructure in Poland is associated with significant support provided for that purpose by the European Union, especially, by investments in the modernization of existing railway lines. Together with the improvement of the infrastructure in less developed countries, an interoperability of rail system at the international level is sought through the technical harmonization, mostly by the introduction of European regulations and technical standards. The paper presents the main requirements associated with the geotechnical aspects of design of railway embankments, mostly relating to their overall stability and maintenance of serviceability. Some aspects of the European standards as well as international, national, and internal regulations, are discusses in the context of challenges encountered by designers. The main geotechnical issues are associated with safety requirements, loading conditions, geometry of railway embankments, as well as the scope of geotechnical investigation necessary to make an informed decision on a final design solution.
Monitoring of air tunnels in a cylindrical storage device using ECT tomography
Authors: Žurovec David , Hlosta Jakub , Nečas Jan , Rozbroj Jiří , Zegzulka Jiří
Published: January 2019

This article focuses on the monitoring of air tunnels in sand, which in common practice are characterised as flow disturbances in the flow of bulk materials inside storage devices, hoppers, silos etc. In this case air tunnels are monitored by the ECT (Electrical Capacitance Tomography) method. The basic principle of the ECT tomographic method is the measurement of permittivity of a measured non-conducting medium. The results gained by an ECT device are then compared with the real, precisely defined measured state. The measured results show that the monitoring of flow disturbances in storage devices using ECT is a new method which does not use optical methods during measurement.
Fatigue Damage Analysis of Composite Insulator Cor Rod/sheath Interface
Authors: Zhao Xinze , Xi Senming , Zhao Meiyun , PENG Wenyun , Tian Seng , Li Wei
Published: January 2019

A self-made fatigue testing machine was used to simulate the damage process of the insulator interface under working conditions and the damage degree is evaluated by the compressive shear test. The improved interface adhesion model reflects the interface debonding process under different fatigue loads by introducing the damage coefficient χ, migration coefficient α and the debonding coefficient μ. The relationship of fatigue loads and interface damage is established by the peeling force, the unit interface separation work and the peeling time. The test demonstrates that the interface damage near the bottom of the insulator is worse than that near the middle part. The result of this analysis will be beneficial in easily finding damaged places of the insulator, and so as to reduce the power breakdown.
Structure integrated shape memory polymer composites for multidimensional forming
Authors: Timmel Tristan , Hackert Alexander , Osiecki Tomasz , Gerstenberger Colin , Kroll Lothar
Published: January 2019

Large-scale curved structures such as wind turbine wings usually require a special and cost intensive transport to the installation destination. These transport and installation costs can be reduced by a flat transport condition and the possibility of layering several structural components. For this reason, the focus at the Department of Lightweight Structures and Polymer Technology at TU Chemnitz was on a novel active material composite, which enables resource-efficient mass production and has a new component architecture. The large-volume multidimensional curvature of the active structure could be achieved by using a shape memory polymer (SMP). The associated reduction of the specific investment costs, the use of materials and the possibility of an integrative design, can contribute to the fact that, for example, the small wind turbines will become an economically viable investment in the future. The active structure influencing was represented by means of a finite element simulation (FEM) for different material composites and could be verified by generic demonstrators regarding its validity.
NDE Detection and Characterization of Damage in Honeycomb Sandwich Composites
Authors: Im Kwang-Hee , Kim Sun-Kyu , Cho Young-Tae , Woo Yong-Deuck , Jung Jong-An , Hsu David Kuei
Published: January 2019

This study deals with a non-destructive evaluation technique for detecting defects in composite panels. In this non-destructive evaluation technique, various low-frequency techniques are applied such as a tapping technology. Another terahertz wave application will be utilized. In particular, the tapping technique is utilized in order to evaluate the characteristics of the honeycomb member based on the hysteresis effect analysis. Here, the area surrounded by the hysteresis loop in the force-displacement curve is related to the increased internal friction loss that is the cause of the energy absorption absorbed by the composite member after the load is applied. The loop area where the composite member was damaged was well agreed with the damage level. Artificial defects were manufactured on the surface of honeycomb sandwich composite panels. An NDE technique was proposed in order to detect defects by using terahertz waves and was discussed for tuning the practical use.
Tests of geosynthetics-reinforced ballast stressed state under heavy trains
Authors: Petriaev Andrei , Konon Anastasia
Published: January 2019

Nowadays requirements for strength and stability of railway subgrade are increased. It occurs due to raising of train speed and axle load. Some sections of subgrade that were previously considered stable do not satisfy safety requirements. In this regard, superstructure reinforcing solutions need to be developed. This paper highlights ballast and subgrade reinforcement applications of geogrids in railway infrastructure. In recent years, geosynthetics are widely used for this purpose. The paper describes recent studies, which helped to identify geosynthetics reinforcement influence on ballast layer and subgrade. Influence of axial load on stress in ballast and subgrade was determined. Obtained data showed that design solutions are required to provide subgrade top bearing capacity in terms of operation with axle loads over 220 kN. Design solution is protective layers installation of polystyrene or geogrids. Five types of geosynthetic materials were placed on the top of subgrade to study vertical stresses distribution in ballast under freight train.
Return traction current system’s operation in cold climate regions
Authors: Makasheva Svetlana , Pinchukov Pavel
Published: January 2019

The paper deals the problem of the reverse traction current's asymmetry at the AC electrified railways. The features of return traction current system’s operation under conditions of cold climate are considered. The goal of work is to determinate value of return traction current asymmetry coefficient for cold climate regions operating AC electrified railways. To achieve the goal the methods of scientific analysis, imitation modelling, experimental study are used. Types and rationing of return traction current asymmetry are accented. The return traction current system model is created in Multisim 12.0 software for analyse the degree of various factors influence on the return traction current's asymmetry. Main influencing factors for asymmetry coefficient in cold climate regions as a traction current value and catenary tower resistance are considered. The calculated graphic dependences of the asymmetry coefficient as a function of the traction current and the catenary tower resistance are given. Algorithm for identifying the critical zones (hazardous areas) by graphical dependencies and predicting the system's predicament states is described.
Experience in the restoration of permafrost degradation areas adjacent to transport infrastructure facilities
Authors: Ustyan Nahapet
Published: January 2019

The construction of transport facilities in the regions of the Extreme (or Far) North and the Arctic Zone is a very specific task with plenty of peculiarities. This can be referred to ever-frozen subsoils, hard-to-reach areas, low temperatures most of the year, as well as limited reserves of inert materials (stone, construction sand) used for construction.