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Abstract

The lubrication of angular contact ball bearings under high-speed motion conditions is particularly important to the working performance of rolling bearings. Combining the contact characteristics of fluid domain and solid domain, a lubrication calculation model for angular contact ball bearings is established based on the RNG k-ε method. The pressure and velocity characteristics of the bearing basin under the conditions of rotational speed, number of balls and lubricant parameters are analyzed, and the lubrication conditions and dynamics of the angular contact ball bearings under different working conditions are obtained. The results show that the lubricant film pressure will rise with increasing speed and viscosity of the lubricant. The number of balls affects the pressure and velocity distribution of the flow field inside the bearing but has a small effect on the values of the characteristic parameters of the bearing flow field. The established CFD model provides a new approach to study the effect of fluid flow on bearing performance in angular contact ball bearings.
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Bibliography

[1] B. Yan, L. Dong, K. Yan, F. Chen, Y. Zhu, and D. Wang. Effects of oil-air lubrication methods on the internal fluid flow and heat dissipation of high-speed ball bearings. Mechanical Systems and Signal Processing, 151:107409, 2021. doi: 10.1016/j.ymssp.2020.107409.
[2] H. Bao, X. Hou, X. Tang, and F. Lu. Analysis of temperature field and convection heat transfer of oil-air two-phase flow for ball bearing with under-race lubrication. Industrial Lubrication and Tribology, 73(5):817–821, 2021. doi: 10.1108/ilt-03-2021-0067/v2/decision1.
[3] T.A. Harris. Rolling Bearing Analysis. Taylor & Francis Inc. 1986.
[4] T.A. Harris and M.N. Kotzalas. Advanced Concepts of Bearing Technology. Taylor & Francis Inc. 2006.
[5] F.J. Ebert. Fundamentals of design and technology of rolling element bearings. Chinese Journal of Aeronautics, 23(1):123-136, 2010. doi: 10.1016/s1000-9361(09)60196-5.
[6] T.A. Harris. An analytical method to predict skidding in high speed roller bearings. A S L E Transactions, 9(3):229–241, 1966. doi: 10.1080/05698196608972139.
[7] A. Wang, S. An, and T. Nie. Analysis of main bearings lubrication characteristics for diesel engine. In: IOP Conference Series: Materials Science and Engineering, 493(1):012135, 2019. doi: 10.1088/1757-899X/493/1/012135.
[8] W. Zhou, Y. Wang, G. Wu, B. Gao, and W. Zhang. Research on the lubricated characteristics of journal bearing based on finite element method and mixed method. Ain Shams Engineering Journal, 13(4):101638, 2022. doi: 10.1016/j.asej.2021.11.007.
[9] J. Chmelař, K. Petr, P. Mikeš, and V. Dynybyl. Cylindrical roller bearing lubrication regimes analysis at low speed and pure radial load. Acta Polytechnica, 59(3):272–282, 2019. doi: 10.14311/AP.2019.59.0272.
[10] C. Wang, M. Wang, and L. Zhu. Analysis of grooves used for bearing lubrication efficiency enhancement under multiple parameter coupling. Lubricants, 10(3):39, 2022. doi: 10.3390/lubricants10030039.
[11] Z. Xie and W. Zhu. An investigation on the lubrication characteristics of floating ring bearing with consideration of multi-coupling factors. Mechanical Systems and Signal Processing, 162:108086, 2022. doi: 10.1016/j.ymssp.2021.108086.
[12] M. Almeida, F. Bastos, and S. Vecchio. Fluid–structure interaction analysis in ball bearings subjected to hydrodynamic and mixed lubrication. Applied Sciences, 13(9):5660, 2023. doi: 10.3390/app13095660.
[13] J. Sun, J. Yang, J. Yao, J. Tian, Z. Xia, H. Yan, and Z. Bao. The effect of lubricant viscosity on the performance of full ceramic ball bearings. Materials Research Express, 9(1):015201, 2022. doi: 10.1088/2053-1591/ac4881.
[14] D.Y. Dhande and D.W. Pande. A two-way {FSI} analysis of multiphase flow in hydrodynamic journal bearing with cavitation. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 39:3399–3412, 2017. doi: 10.1007/s40430-017-0750-8.
[15] H. Liu, Y. Li, and G. Liu. Numerical investigation of oil spray lubrication for transonic bearings. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 40:401, 2018. doi: 10.1007/s40430-018-1317-z.
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Authors and Affiliations

Bowen Jiao
1
ORCID: ORCID
Qiang Bian
1
ORCID: ORCID
Xinghong Wang
1
Chunjiang Zhao
1
ORCID: ORCID
Ming Chen
1
Xiangyun Zhang
2

  1. School of Mechanical Engineering, Taiyuan University of Science and Technology, Taiyuan, China
  2. Luoyang Bearing Research Institute Co., Ltd, Luoyang, China
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Abstract

Risks pertaining to construction work relate to situations in which various events may randomly change the duration and cost of the project or worsen its quality. Because of possible significant changes of random events, favorable, moderate, and difficult conditions of construction work are considered. It is the first stage of the construction risk analysis. The probabilistic parameters of construction are identified and described by using the design characteristics model of the structure and the construction technology model. The first describes the probabilistic properties of the structure execution's technology. The second describes the probabilistic properties of the works execution. Both models contain basic probabilistic data for scheduling, cost estimating, and risk assessment of the construction.

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Authors and Affiliations

T. Kasprowicz
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Abstract

Buckling and postbuckling response of thin-walled composite plates investigated experimentally and determinated analytically and numerically is compared. Real dimension specimens of composite plates weakened by cut-out subjected to uniform compression in laboratory buckling tests have been modelled in the finite element method and examined analytically based on P-w2 and P-w3 methods. All results were obtained during the experimental investigations and the numerical FEM analysis of a thin-walled composite plate made of a carbon-epoxy laminate with a symmetrical eight-layer arrangement of [90/-45/45/0]s. The instrument used for this purpose was a numerical ABAQUS® program.

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Authors and Affiliations

K. Falkowicz
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Abstract

The paper presents a method of priority scheduling that is useful during the planning of multiple-structure construction projects. This approach is an extension of the concept of interactive scheduling. In priority scheduling, it is the planner that can determine how important each of the technological and organisational constraints are to them. A planner's preferences can be defined through developing a ranking list that defines which constraints are the most important, and those whose completion can come second. The planner will be able to model the constraints that appear at a construction site more flexibly. The article presents a general linear programming model of the planning of multiple-structure construction projects, as well as various values of each of the parameters that allow us to obtain different planning effects. The proposed model has been implemented in a computer program and its effectiveness has been presented on a calculation example.

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Authors and Affiliations

E. Radziszewska-Zielina
B. Sroka
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Abstract

Considering concrete nonlinearity, the wave height limit between small and large amplitude sloshing is defined based on the Bernoulli equation. Based on Navier-Stokes equations, the mathematical model of large amplitude sloshing is established for a Concrete Rectangle Liquid-Storage Structure (CRLSS). The results show that the seismic response of a CRLSS increases with the increase of seismic intensity. Under different seismic fortification intensities, the change in trend of wave height, wallboard displacement, and stress are the same, but the amplitudes are not. The areas of stress concentration appear mainly at the connections between the wallboards, and the connections between the wallboard and the bottom.

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Authors and Affiliations

X. Cheng
D. Li
P. Li
X. Zhang
G. Li
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Abstract

In this paper, the authors present a robot for pipe inspection and exploration, which has in its structure a module for the maintenance of a constant pressure force between the robot's wheels and the inside diameter of the pipe. The paper starts with a short introduction about necessity of the presented solution followed by design aspects and finalizing with the test of the developed compliant module.

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Authors and Affiliations

Claudiu Cirebea
Mihai Tatar
Vistrian Matieş
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Abstract

The protection of Polish architectural heritage in the former eastern borderlands, accomplished through the conservation and technical securing of historical structures, constitutes one of the main programmes that are implemented by the Ministry of Culture and National Heritage. Currently, many Polish historical buildings in the former eastern borderlands are in a very bad technical condition. The load-bearing systems of these elements, as well as elements of their finish, require immediate emergency securing work. The basic steps that precede conservation work are emergency structural works, which guarantee the durability and stability of the entire historical substance. The specifics and complexity of the problem of the failure of historical buildings often demands an in-depth analysis of a series of factors that are difficult to measure and which are responsible for the cause and effect relationship during the early stage of the technical evaluation of a structure. The analyses of failures of numerous historical structures, for instance that were carried out by the authors, have become the inspiration for the search for effective methods of analysis that would allow for an in-depth analysis of the causes and effects of the failures in question. The DEMATEL method (Decision Making Trial and Evaluation Laboratory) that has been presented in this work, and its fuzzy extension, has lately become one of the more popular methods used in the cause-and-effect analysis of various phenomena. The authors demonstrated how this method works on the example of the evaluation and securing of the load-bearing system of the XVII Collegiate church of the Holy Trinity in the town of Olykha in the Volhynskiy Oblast, Ukraine.

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Authors and Affiliations

G. Śladowski
R. Paruch
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Abstract

In Part I of this article, two-stage solidification model was presented. In this part we use our model to simulate solidification of the Al 7% Si alloy for two cooling rates and . Simulations have been performed for two eutectic transformation modes, typical for modified and unmodified alloys. Obtained cooling curves are qualitatively consistent with the typical cooling curves for modified and unmodified alloys. Moreover, evolution of cooling-curve characteristics is compared with the analytical model and found to be in close agreement.

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Authors and Affiliations

E. Gawrońska
O. Wodo
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Abstract

The paper presents adaptation problem of lamellar/rod growth of eutectic. The transformation of eutectic microstructure was investigated systematically. A interpretation of the eutectic growth with theory minimum entropy production was presented.

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Authors and Affiliations

M. Trepczyńska-Łent
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Abstract

The paper presents a new numerical model of solidification processes in hypoeutectic alloys. The model combines stochastic elements, such as e.g. random nucleation sites and orientation of dendritic grains, as well as deterministic methods e.g. to compute velocity of dendritic tips and eutectic grains. The model can be used to determine the temperature and the size of structure constituents (of both, the primary solid phase and eutectics) and the arrangement of individual dendritic and eutectic grains in the consecutive stages of solidification. Two eutectic transformation modes, typical to modified and unmodified hypoeutectic alloys, have been included in the model. To achieve this, cellular automata and Voronoi diagrams have been utilized.

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Authors and Affiliations

E. Gawrońska
O. Wodo
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Abstract

One of the more important elements of spatial information infrastructure is the organisational structure defining the obligations and dependencies between stakeholders that are responsible for the infrastructure. Many SDI practitioners and theoreticians emphasise that its influence on the success or failure of activities undertaken is significantly greater than that of technical aspects. Being aware of the role of the organisational structure in the creating, operating and maintenance of spatial information infrastructure (SII), Polish legislators placed appropriate regulations in the Spatial Information Infrastructure Act, being the transposition of the INSPIRE Directive into Polish Law. The principal spatial information infrastructure stakeholders are discussed in the article and also the scope of cooperation between them. The tasks and relationships between stakeholders are illustrated in UML, in both the use case and the class diagram. Mentioned also are the main problems and obstructions resulting from imprecise legal regulations.
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Authors and Affiliations

Elżbieta Bielecka
Agnieszka Zwirowicz-Rutkowska
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Abstract

In this study, modification of the AZ91 magnesium alloy surface layer with a CO2 continuous wave operation laser has been taken on. The

extent and character of structural changes generated in the surface layer of the material was being assessed on the basis of both macro- and

microscopy investigations, and the EDX analysis. Considerable changes in the structure of the AZ91 alloy surface layer and the

morphology of phases have been found. The remelting processing was accompanied by a strong refinement of the structure and a more

uniform distribution of individual phases. The conducted investigations showed that the remelting zone dimensions are a result of the

process parameters, and that they can be controlled by an appropriate combination of basic remelting parameters, i.e. the laser power, the

distance from the sample surface, and the scanning rate. The investigations and the obtained results revealed the possibility of an effective

modification of the AZ91 magnesium alloy surface layer in the process of remelting carried out with a CO2 laser beam.

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Authors and Affiliations

J. Iwaszko
M. Strzelecka
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Abstract

The academic environment of Wrocław emerged and developed in particularly difficult conditions of the post WWII era. Thanks to continuation of the tradition, experience and contributions of leading scientists from the former Jan Kazimier University of Lwów, it quickly achieved an important, internationally recognized position in particular in mathematics and chemistry. Two different sociological concepts of relations within the scientific community have developed simultaneously: (1) partnership between leaders and research team members, (2) hierarchical structure based on authority of a leader. History proved that both may be effective. Wrocław became a modern center of research management comparable to leading western universities. The general approach based on relationship „between master and a follower” has been replaced by the more effective relatioship „between a school and a follower”. Similarly to the Lwów tradition the Wrocław Scientific Society has played an integrative role in relations among scientists of different disciplines.

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Authors and Affiliations

Wacław Kasprzak
Karol I. Pelc
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Abstract

In this paper, existing knowledge on the behaviour of soil-steel composite structures (SSCSs) has been reviewed. In particular, the response of buried corrugated steel plates (CSPs) to static, semistatic, and dynamic loads has been covered. Furthermore, the performance of SSCS under extreme loading, i.e., loading until failure, has been studied. To investigate the behaviour of the type of composite structures considered, numerous full-scale tests and numerical simulations have been conducted for both arched and box shapes of the shell. In addition, researchers have examined different span lengths and cover depths. Furthermore, to enhance the load-bearing capacity of the composite structures, various stiffening elements have been applied and tested. The reviewshows that the mechanical features of SSCSs are mainly based on the interaction of the shell with the soil backfill. The structures, as a composite system, become appropriately stiff when completely backfilled. For this reason, the construction phase corresponds to the highest values of shell displacement and stress. Moreover, the method of laying and compacting the backfill, as well as the thickness of the cover, has a significant impact on the behaviour of the structure at the stage of operation in both the quantitative and qualitative sense. Finally, a limited number of studies are conducted on the ultimate bearing capacity of large-span SSCS and various reinforcing methods. Considerably more works will need to be done on this topic. It applies to both full scale tests and numerical analysis.
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Authors and Affiliations

Alemu Mosisa Legese
1
ORCID: ORCID
Maciej Sobótka
1
ORCID: ORCID
Czesław Machelski
1
ORCID: ORCID
Adrian Różański
1
ORCID: ORCID

  1. Wrocław University of Science and Technology, Faculty of Civil Engineering, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
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Abstract

The objective of the article is to examine the approximative and adjustive uses of the verb dire, which is mostly regarded as an assertive and eventful verb; hence nonapproximative. Meanwhile, in many expressions, in an impersonal use, in negation when the subjunctive mode is used, in the conditional forms, its evidence value is weakened and the verb dire can express approximation. The study is situated in light of the enunciation theory, notably it refers to a notion of modalisation. The corpus was established on the basis of dictionaries, which are representative for normative uses, but we will refer as well to press texts, particularly interviews, where the verb say is frequently used as a marker of the position of the speaker.

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Authors and Affiliations

Katarzyna Kwapisz-Osadnik
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Abstract

One of the challenges of modern crystallography of complex systems (complex metallic alloys, proteins, aperiodic crystals and quasicrystals) is to properly describe the disorder in these systems and discuss correctly the refinement results in terms of the structural disorder. In this paper we briefly discuss a new approach to phasons and phonons in quasicrystals and focus on the new theory of phonons in these materials. A newly derived correction factor for phonons in the form of the Bessel function is the approximated way of describing optic modes in the phonon spectra of quasicrystals. It is applied to a real decagonal quasicrystal in the Al-Cu-Rh system with 56/38 atoms per thick/thin structural unit, based on 2092 unique reflections selected from the collected diffraction data, significantly improving the refinement results. The final R-factor value is 7.24%, which is over 0.5% better result comparing to originally reported. We believe our work will open a broader discussion on the disorder in quasicrystals (and other aperiodic systems) and motivate to develop new approaches to treat the diffraction data influenced by different types of disorder in the new way.

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Authors and Affiliations

R. Strzałka
I. Bugański
J. Śmietańska
J. Wolny
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Abstract

The article presents the process of structural diagnostics of the Dominican monastery in Lublin. In order to establish the underlying cause of cracks, not only in situ investigations but also detailed analyses of documents were executed. Inventory drawings were examined in order to identify the building’s structural system. The query of historical documents and city archives was carried out to understand the structure’s performance. Conclusions were confronted with the crack pattern. It was established that the damage resulted from the original conditions of the structural system in place. These conditions were created in past, when the monastery incorporated sections of the medieval town wall into its structure.
The article details structural remedies applied in the course of rehabilitation. The introduction of supporting structures was the effect of a compromise between the necessity of ensuring structural safety and the demand for the minimum impact on the heritage site. The article aims to highlight that the structural assessment of the heritage asset is an investigative process. The work also emphasizes that in spite of numerous up-to-date methods helpful in the structural diagnostics of building structure, the conceptual analyses of the structural system still remain of vital importance. The query of historical documents helps in determining the structural system of a historic building, and vice versa, structural analyses assist in recognizing and supplementing the knowledge of the asset’s history.
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Bibliography

[1] E. Radziszewska-Zielina, G. Sladowski, “Supporting the selection of a variant of the adaptation of a historical building with the use of fuzzy modelling and structural analysis”, Journal of Cultural Heritage, 2017, vol. 26, pp. 53–63.
[2] L. Czarnecki and D. Van Gemert, “Scientific basis and rules of thumb in civil engineering: conflict or harmony”, Bulletin of Polish Academy of Science: Technical sciences, 2016, vol. 64, pp. 665–673.
[3] G. Barbieri, M. Valente, L. Biolzi, C. Togliani, L. Fregonese, G. Stanga, “An insight in the late Baroque architecture: An integrated approach for a unique Bibiena church”, Journal of Cultural Heritage, 2017, vol. 23, pp. 58–67.
[4] M. P. Sammartino, G. Cau, R. Reale, S. Ronca, G. Visco, “A multidisciplinary diagnostic approach preliminary to the restoration of the country church “San Maurizio” located in Ittiri (SS)”, Heritage Science 2, 2014, vol. 4.
[5] E. Diz-Mellado, E.J. Mascort-Albea, R. Romero-Hernández, C. Galán-Martín, C. Rivera-Gòmez, J. Ruiz- Jaramillo, A. Jaramillo-Morilla, “Non-destructive testing and Finite Element Method integrated procedure for heritage diagnosis: The Seville Cathedral case study”, Journal of Building Engineering, 2021, vol. 37, p. 102134.
[6] M.F. Funari, S. Spadea, P. Lonetti, F. Fabbrocino, R. Luciano, “Visual programming for structural assessment of out-of-plane mechanism in historic masonry structures”, Journal of Building Engineering, 2020, vol. 31, p. 101425.
[7] M.A. Nùñez-Andrés, F. Buill, A. Costa-Jover, J.M. Puche, “Structural assessment of Roman wall and vaults in the cloister of Tarragona Cathedral”, Journal of Building Engineering, 2017, vol. 13, pp. 77–86.
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[9] ICOMOS: “Recommendation for the analysis, conservation and structural restoration of architectural heritage”. 2003. Website of International Council of Monuments and sites. https://www.icomos.org/en/aboutthe-centre/179-articles-en-francais/ressources/charters-and-standards/165-icomos-charter-principles-forthe- analysis-conservation-and-structural-restoration-of-architectural-heritage. Accessed 10 Feb. 2021
[10] C. Alessandri, V. Mallardo, “Structural assessments of the Church of the Nativity in Bethlehem”, Journal of Cultural Heritage, 2012, vol. 13, Supplement, pp. e61–e69.
[11] A. Anzani, L. Binda, A. Carpinteri, S. Invernizzi, G. Lacidogna, “A multilevel approach for the damage assessment of Historic masonry towers”, Journal of Cultural Heritage, 2010, vol. 11, pp. 459–470.
[12] L. Binda, A. Saisi, C. Tiraboschi, “Investigation procedures for the diagnosis of historic masonries”, Construction and Building Materials, 2000, vol. 14, pp. 199–233.
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[14] M-G. Masciotta, L. F. Ramos, P. B.Lourenço, “The importance of structural monitoring as a diagnosis and control tool in the restoration process of heritage structures: A case study in Portugal”, Journal of Cultural Heritage, 2017, vol. 27, pp. 36–47.
[15] G. Teza, S. Trevisani, A. Pesci, “The role of geoenvironmental sciences in Cultural Heritage preservation: the case of 1000 year old leaning bell tower of Caorle (Venice)”. Journal of Cultural Heritage, 2019, vol. 39, pp. 270–277.
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Authors and Affiliations

Anna Halicka
1
ORCID: ORCID
Anna Ostańska
1
ORCID: ORCID

  1. Lublin University of Technology, Faculty of Civil Engineering and Architecture, ul. Nadbystrzycka 40, 20-618 Lublin
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Abstract

The results of analysis of geometrical structure of modular networks are discussd in the paper. The criteria of technical correctness of such construction were determined. The algebraic relationship between the network components, e.g. station number, tie points, number of measurements, was analysed. The determination conditions for a single module and for a surface network have been introduced considering the existence of elementary modules that are not internally determined. A comparative test for modular and classical models of network was performed using a computer program. The results illustrate positioning accuracy achievable with use of modular networks. The conclusions presented might be helpful when designing surveying networks.
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Authors and Affiliations

Tadeusz Gargula
ORCID: ORCID
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Abstract

Seismic refraction studies on Central Spitsbergen have shown that there is the fault systems with north-south strike directions, which divide the crust into western, central and eastern blocks. Thickness of the crust in this area varies from 35 to 40 km. Interpretation and modelling of seismic refraction data indicate that the Moho boundary beneath the Central Spitsbergen Basin is a complicated transition zone between crust and upper mantle with the thickness of about 5 km.

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Authors and Affiliations

Aleksander Guterch
Edward Perchuć
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Abstract

The presence of Euphausia superba, E. crystallorophias and Thysanoessa macrura was observed in Admiralty Bay (King George Island, South Shetland Islands) and the size of individuals of particular species are diverse and varying during the summer season. E. superba population is older and specimens larger than in analogous season in 1979. The maximum number of females with eggs was noted in the first half of January 1980, i.e. earlier than in 1979. In E, crystallorophias population the presence of females with eggs was observed in the second half of December 1979.

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Authors and Affiliations

Hanna Jackowska
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Abstract

On the basis of 35 one-hour series of the measurement of the wind velocity, read out every two minutes, the wind structure at the Arctowski Station, situated on Admiralty Bay, King George Island, was analysed. Very strong turbulence was found with air flow directions from over the area of the Island (S, SW. W and NW) and laminarity with directions from SE, E, NE and partly N, i.e. when the air flows from Admiralty Bay or from over the open waters of Bransfield Strait. The qustiness coefficient, the relationship between the maximum and mean velocities and the intensity of turbulence were determined for the two flow types. Two extremely different cases, in terms of flow character, were considered, by determining for them the distributions of instantaneous velocities and those of oscillations.

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Authors and Affiliations

Dominik Kowalski
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Abstract

Power spectrum techniques were applied to two time series of wind speed values recorded at the Arctowski Station in order to investigate the influence of turbulent and laminar air flow on the quasi-periodicity of the micro-scale wind structure.

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Authors and Affiliations

Ewa Skrzypczak
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Abstract

The objective of the paper is to use the model of Complexity Scales and Licensing (Cyran 2003, 2010) to account for the existence of two prosodic types: ‘syllable’ and ‘word’ languages (Auer 1993, Szczepaniak 2007), which roughly correspond to syllable-timed and stress-timed languages. We will postulate that these categories are not primitive and that many of their phonological characteristics can be derived from simpler mechanisms of licensing. It will be also argued that the phenomenon of contrast plays an important role in prosodic typology and may infl uence syllable structure. Languages use more marked syllabic confi gurations in order to optimise contrast expression. We will carry out an analysis on a simple hypothetical language in order to demonstrate the interdependence of syllabic complexity and the contrastive potential of a syllabic unit.
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Authors and Affiliations

Marcin Fortuna

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