Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 61
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

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.

Go to article

Authors and Affiliations

Katarzyna Kwapisz-Osadnik
Download PDF Download RIS Download Bibtex

Abstract

The problem considered is that of an isotropic, micropolar thermoelastic medium with voids subjected to the Thomson effect. The solution to the problem is presented in the context of the refined multiphase- lags theory of thermoelasticity. The normal mode analysis was used to obtain the analytical expressions of the considered variables. The nondimensional displacement, temperature, microrotation, the change in the volume fraction field and stress of the material are obtained and illustrated graphically. The variations of these quantities have been depicted graphically in the refined-phase-lag theory, Green and Naghdi theory of type II, Lord and Shulman theory and a coupled theory. The effects of the Thomson parameter and phase lag parameters on a homogeneous, isotropic, micropolar thermoelastic material with voids are revealed and discussed. Some particular cases of interest are deduced from the present investigation.
Go to article

Bibliography

[1] Biot M.A.: Thermoelasticity and irreversible thermodynamics. J. Appl. Phys. 7(1956), 3, 240–253.
[2] Lord H.W., Shulman Y.: A generalized dynamical theory of thermoelasticity. J. Mech. Phys. Sol. 15(1967), 5, 299–309.
[3] Green A.E., Lindsay K.A.: Thermoelasticity. J. Elast. 2(1972), 1, 1–7.
[4] Green A.E., Naghdi P.M.: A re-examination of the basic postulates of thermosmechanics. Proc. R. Soc. Lond. A 432(1991), 1885, 171–194.
[5] Green A.E., Naghdi P.M.: On undamped heat wave in elastic solids. J. Therm. Stress. 15(1992), 2, 253–264.
[6] Green A.E., Naghdi P.M.: Thermoelasticity without energy dissipation. J. Elast. 31(1993), 189–209.
[7] Tzou D.Y.: The generalized lagging response in small-scale and high-rate heating. Int. J. Heat Mass Trans. 38(1995), 17, 3231–3240.
[8] Tzou D.Y.: A unified field approach for heat conduction from macro- to microscales. J. Heat Trans. 117(1995), 1, 8–16.
[9] Roy Choudhuri S.K.: On a thermoelastic three-phase-lag model. J. Therm. Stress. 30(2007), 3, 231–238.
[10] Eringen A.C.: Linear theory of micropolar elasticity. ONR Techn. Rep. 29 (School of Aeronautics, Aeronautics and Engineering Science), Purdue Univ., West Lafayett 1965.
[11] Eringen A.C.: A unified theory of thermomechanical materials. Int. J. Eng. Sci. 4(1966), 2, 179–202.
[12] Eringen A.C.: Linear theory of micropolar elasticity. J. Math. Mech. 15(1966), 6, 909–924.
[13] Nowacki W.: Couple stresses in the theory of thermoelasticity III. Bull. Acad. Pol. Sci. Tech. Ser. Sci. Tech. 14(1966), 8, 801–809.
[14] Tauchert T.R., Claus Jr. W.D., Ariman T.: The linear theory of micropolar thermo- elasticity. Int. J. Eng. Sci. 6(1968), 1, 36–47.
[15] Nowacki W., Olszak W. (Eds.): Micropolar Thermoelasticity. CISM Courses and Lectures 151, Springer-Verlag, Vienna 1974.
[16] Dhaliwal R.S., Singh A.: Micropolar thermoelasticity. In: Thermal Stresses II (R.B. Hetnarski, Ed.), Elsevier, Amsterdam 1987.
[17] Marin M., Nicaise S.: Existence and stability results for thermoelastic dipolar bodies with double porosity. Continuum Mech. Thermodyn. 28(2016), 6, 1645–1657.
[18] Marin M., Ellahi R., Chirila A.: On solutions of Saint–Venant’S problem for elastic dipolar bodies with voids. Carpathian J. Math. 33(2017), 2, 219–232.
[19] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: Effect of rotation on micropolar generalized thermoelasticity with two temperatures using a dual-phase lag model. Can. J. Phys. 92(2014), 2, 148–159.
[20] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: The influence of thermal loading due to laser pulse on generalized micropolar thermoelastic solid with comparison of different theories. Multi. Model. Mater. Struct. 10(2014), 3, 328–345.
[21] Chandrasekharaiah D.S.: Heat flux dependent micropolar thermoelasticity. Int. J. Eng. Sci. 24(1986), 8, 1389–1395.
[22] Othman M.I.A., Hasona W.M., Abed-Elaziz E.M.: Effect of rotation and initial stresses on generalized micropolar thermoelastic medium with three-phase-lag. J. Comput. Theor. Nanosci. 12(2015), 9, 2030–2040.
[23] Othman M.I.A., Abed-Elaziz E.M.: Effect of rotation and gravitational on a micropolar magneto-thermoelastic medium with dual-phase-lag model. Microsyst. Tech. 23(2017), 10, 4979–4987.
[24] Othman M.I.A., Abd-alla A.N., Abed-Elaziz E.M.: Effect of heat laser pulse on wave propagation of generalized thermoelastic micropolar medium with energy dissipation. Ind. J. Phys. 94(2020), 3, 309–317.
[25] Cowin S.C., Nunziato J.W.: Linear elastic materials with voids. J. Elast. 13(1983), 2, 125–147.
[26] Othman M.I.A., Abed–Elaziz E.M.: The effect of thermal loading due to laser pulse in generalized thermoelastic medium with voids in dual-phase-lag model. J. Therm. Stress. 38(2015), 9, 1068–1082.
[27] Abd-Elaziz E.M., Othman M.I.A.: Effect of Thomson and thermal loading due to laser pulse in a magneto-thermoelastic porous medium with energy dissipation. ZAMM-Z. Angew. Math. Me. 99(2019), 8, 201900079.
[28] Abd-Elaziz E.M., Marin M., Othman M.I.A.: On the effect of Thomson and initial stress in a thermos-porous elastic solid under G-N electromagnetic theory. Symmetry. 11(2019), 3, 413–430.
[29] Othman M.I.A., Marin M.: Effect of thermal loading due to laser pulse on thermoelastic porous media under G-N theory. Results Phys. 7(2017), 3863–3872.
[30] Othman M.I.A, Abd-Elaziz E.M.: Plane waves in a magneto-thermoelastic solids with voids and microtemperatures due to hall current and rotation. Results Phys. 7(2017), 4253–4263.
[31] Othman M.I.A., Tantawi R.S., Eraki E.E.M.: Effect of rotation on a semi conducting medium with two-temperature under L–S theory. Arch. Thermodyn. 38(2017), 2, 101–122.
[32] Chirita S., Ciarletta M., Tibullo V.: On the thermomechanical consistency of the time differential dual-phase-lag models of heat conduction. Int. J. Heat Mass Tran. 114(2017), 277–285.
[33] https://matlab.mathworks.com/ (accessed 17 Feb. 2021)
Go to article

Authors and Affiliations

Amnah M. Alharbi
1
Elsayed M. Abd-Elaziz
2
Mohamed I.A. Othman
3

  1. Taif University, Department of Mathematics, College of Science, P.O. Box 11099, Taif, 21944, Saudi Arabia
  2. Ministry of Higher Education, Zagazig Higher Institute of Engineering & Technology, Zagazig, Egypt
  3. Zagazig University, Department of Mathematics, Faculty of Science, P.O. Box 44519, Zagazig, Egypt
Download PDF Download RIS Download Bibtex

Abstract

In this study, free and forced vibration responses of carbon nanotube reinforced uniform and tapered composite beams are investigated. The governing differential equations of motion of a carbon nanotube (CNT) reinforced uniform and tapered composite beams are presented in finite element formulation. The validity of the developed formulation is demonstrated by comparing the natural frequencies evaluated using present FEM with those of available in literature. Various parametric studies are also performed to investigate the effect of aspect ratio, percentage of CNT content, ply orientation, and boundary conditions on natural frequencies and mode shapes of a CNT reinforced composite beam. It was observed that the addition of carbon nanotube in fiber reinforced polymer composite (FRP) beam enhances the stiffness of the structure which consequently increases the natural frequencies and alters the mode shapes.

Go to article

Authors and Affiliations

Ananda Babu Arumugam
Vasudevan Rajamohan
Naresh Bandaru
Edwin Sudhagar P.
Surajkumar G. Kumbhar
Download PDF Download RIS Download Bibtex

Abstract

The aim of the studywas to find an effective method of ripple torque compensation for a direct drive with a permanent magnet synchronous motor (PMSM) without time-consuming drive identification. The main objective of the research on the development of a methodology for the proper teaching a neural network was achieved by the use of iterative learning control (ILC), correct estimation of torque and spline interpolation. The paper presents the structure of the drive system and the method of its tuning in order to reduce the torque ripple, which has a significant effect on the uneven speed of the servo drive. The proposed structure of the PMSM in the dq axis is equipped with a neural compensator. The introduced iterative learning control was based on the estimation of the ripple torque and spline interpolation. The structurewas analyzed and verified by simulation and experimental tests. The elaborated structure of the drive system and method of its tuning can be easily used by applying a microprocessor system available now on the market. The proposed control solution can be made without time-consuming drive identification, which can have a great practical advantage. The article presents a new approach to proper neural network training in cooperation with iterative learning for repetitive motion systems without time-consuming identification of the motor.

Go to article

Authors and Affiliations

Adrian Wójcik
Tomasz Pajchrowski
Download PDF Download RIS Download Bibtex

Abstract

In this paper, it has been shown that any measuring process can be modeled as a process of sampling of signals. Also, a notion of a special kind of functions, called here functions with attributes, has been introduced. The starting point here, in the first of the above themes, is an observation that in fact we are not able to measure and record truly continuously in time any physical quantity. The measuring process can be viewed as going stepwise that is in steps from one instant to another, similarly as a sampling of signals proceeds. Therefore, it can be modeled as the latter one. We discuss this in more detail here. And, the notion of functions with attributes, we introduced here, follows in a natural way from the interpretation of both the measuring process as well as the sampling of signals that we present in this paper. It turns out to be useful.

Go to article

Authors and Affiliations

Andrzej Borys
ORCID: ORCID
Download PDF Download RIS Download Bibtex

Abstract

The effect of 0.2% addition of Mg, Co and Ce to 99.9% cast aluminium was studied by evaluation of changes in microstructure and mechanical properties. The microstructure was analyzed by scanning electron microscopy and transmission electron microscopy. The Al99.9 alloy contained only Al-Fe-Si phase particles. Similar Al-Fe-Si particles were observed in alloy with 0.2% Mg addition, because this amount of magnesium was fully dissolved in the solid solution. The addition of cobalt resulted in the formation of Al9.02Co1.51Fe0.47 phase particles assuming the shape of eutectic plates. The electron backscattered diffraction map made for the alloy with 0.2% Co addition showed numerous twin boundaries with distances between them in the range from 10 to 100 µm. The addition of cerium was located in the grain boundary area. Cerium also gave rise to the formation of two types of particles, i.e. Al4Ce and Al-Ce-Fe-Si. The Al-Ce-Fe-Si phase is a nucleation site for the Al4Ce phase, which forms eutectic plates. The results showed that the introduction of additives increases the mechanical properties of the cast materials. The 99.9% cast aluminium has a hardness of 16.9 HB. The addition of 0.2% by weight of Mg, Co, Ce increases this hardness to 21.8 HB, 22.6 HB and 19.1 HB, respectively.
Go to article

Authors and Affiliations

P. Koprowski
1
ORCID: ORCID
M. Lech-Grega
1
Ł. Wodzinski
2
ORCID: ORCID
B. Augustyn
1
ORCID: ORCID
S. Boczkal
1
ORCID: ORCID
P. Uliasz
2
ORCID: ORCID
M. Ożóg
2
ORCID: ORCID

  1. Łukasiewicz Research Network – Institute of Non-Ferrous Metals, Division in Skawina, 19 Piłsudskiego Str., 32-050 Skawina, Poland
  2. Boryszew S.A., Modern Aluminium Products, 23 Piłsudskiego Str., 32-050 Skawina, Poland
Download PDF Download RIS Download Bibtex

Abstract

High definition video transmission is one of the prime demands of modern day communication. Changing needs demand diverse features to be offered by the video codec standards, H.264 fits to these requirements for video compression. In this work, an attempt has been made to optimize the inter prediction along with improved intra prediction to ensure the minimal bit rates thereby reduction in the channel bandwidth, which is required in most of the wireless applications. In intraprediction, only DC prediction mode is chosen out of 9 modes with 4*4 luma blocks that reduces the coding complexity towards optimal logic utilization in order to support typical FPGA board for hardware implementation. Most significantly, Inter prediction is carried out utilizing the M9K blocks efficiently with proper timing synchronization to reduce the latency in the encoding operation. Experimental set up comprising of two Altera DE2-115 boards connected through Ethernet cable demonstrated the video transmission. These optimized intra prediction and inter prediction stages resulted in significant improvement in the video compression possessing good subjective quality and increased video compression.
Go to article

Bibliography

[1] Bernatin.T ,Sundari.G, “ Video compression based on Hybrid transform and quantization with Huffman coding for video codec”, International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), pp 476-480,IEEE.
[2] The Evolution of H.264 From Codec to System Architecture, White Paper , VBrick Systems, December, 2010
[3] Arun Kumar Pradhan, Lalit Kumar Kanoje and BiswaRanjan Swain, 2013 “FPGA based High Performance CAVLC Implementation for H.264 Video Coding” International Journal of Computer Applications (0975 – 8887) Volume 69– No.10.
[4] Teng Wang, Chih-Kuang Chen, Qi-Hua Yang and Xin-An Wang (2012), “FPGA Implementation and Verification System of H.264/AVC Encoder for HDTV Applications”, Advances in CSIE, Springer-Verlag Berlin Heidelberg, Vol. 2, AISC 169, pp. 345-352
[5] Gwo-Long Li et al. (2013), “135-MHz258-K gates VLSI design for all-intra H.264/AVC scalable video encoder”, IEEE Trans. Very Large Scale Integr.(VLSI) Syst., Vol. 21, No. 4, pp. 636-647
[6] Kuo, H.-C., Wu, L.-C., Huang, H.-T., Hsu, S.-T. and Lin, Y.-L. (2013), “A low power high-performance H.264/AVC intra-frame encoder for 1080pHD video”, IEEE Trans. Very Large Scale Integr. (VLSI) Syst., Vol. 19, No. 6, pp. 925-938

Go to article

Authors and Affiliations

T. Bernatin
1
G. Sundari
1
Sahaya Anselin Nisha
1
M.S. Godwin Premi
1

  1. Sathyabama Institute of Science and Technology, India
Download PDF Download RIS Download Bibtex

Abstract

In the present study, the influence of the infection with equine herpesvirus type 1 (non-neuropathogenic and neuropathogenic strains of EHV-1) on the morphology and distribution of mitochondrial network in equine dermal cell line was investigated. Our results indicate that EHV-1-infection caused changes in the mitochondrial morphology manifested mostly by fission and reactive oxygen species generation.

Go to article

Authors and Affiliations

M. Bartak
M. Chodkowski
A. Słońska
M.W. Bańbura
J. Cymerys
Download PDF Download RIS Download Bibtex

Abstract

A separate, cat-specific hospitalization room away from dogs is recommended to reduce stress in cats; however, this can be difficult for some hospitals to provide. In such cases, measures are undertaken to reduce the cat’s stress by providing a place to hide. However, inability to observe the cat’s condition may be an obstacle to providing veterinary care. The use of a one-way mirror to create a sheltered environment while allowing observation of the cats was assessed. Five healthy cats were assessed using the Cat Stress Score (CSS) while in a cage with either a transparent panel or a one-way mirror. No significant differences in the CSS between the transparent panel and one-way mirror were observed. Variations in the CSS scores depended on the cat’s personality, with friendlier and more sociable cats showing a lower CSS with the one-way mirror. A one-way mirror may be useful to reduce stress in hospitalized cats.
Go to article

Authors and Affiliations

T. Miyata
1
R. Higuchi
1
K. Yokobori
1
S. Seki
1
K. Ishioka
1

  1. School of Veterinary Nursing and Technology, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino-shi, Tokyo 180-8602, Japan
Download PDF Download RIS Download Bibtex

Abstract

Wireless Sensor Network (WSN) technology has grown in importance in recent years. All WSN implementations need secure data transmission between sensor nodes and base stations. Sensor node attacks introduce new threats to the WSN. As a result, an appropriate Intrusion Detection System (IDS) is required in WSN for defending against security attacks and detecting attacks on sensor nodes. In this study, we use the Routing Protocol for Low Power and Lossy Networks (RPL) for addressing security services in WSN by identifying IDS with a network size of more or less 20 nodes and introducing 10% malicious nodes. The method described above is used on Cooja in the VMware virtual machine Workstation with the InstantContiki2.7 operating system. To track the movement of nodes, find network attacks, and spot dropped packets during IDS in WSN, an algorithm is implemented in the Network Simulator (NS2) using the Ad-hoc On-Demand Distance Vector (AODV) protocol in the Linux operating system.
Go to article

Authors and Affiliations

Joseph Kipongo
1
Theo G. Swart
1
Ebenezer Esenogho
1 2

  1. Center for Telecommunications, Department of Electrical and Electronic Engineering Science, University of Johannesburg, Johannesburg, South Africa
  2. Department of Electrical and Electronic Engineering, University of Botswana, Gaborone, Botswana
Download PDF Download RIS Download Bibtex

Abstract

The problem of determining displacements of objects is an important and current issue, in particular in terms of operational safety. This is a requirement that covers geodetic, periodic control measurements in order to determine horizontal and vertical displacements. The paper is focused on the analysis of vertical displacements. Geodetic measurements and their interpretation allow to reduce the risk of possible structural catastrophes. The major research topic of the majority of available papers is displacement determination of individual controlled points, in a situation where there are identified as fixed reference points. There are cases making identification of such points difficult or impossible to use in displacement analysis. This paper addresses a rare case of determining vertical displacements in unstable reference systems. Due to the fact that most of the existing and known literature methods do not always bring satisfactory results, the paper propose a new method of vertical displacement determination in the absence of reference points in the local coordinate system. Practical considerations on simulated data show that the presented method performs the task correctly.

Go to article

Authors and Affiliations

D. Filipiak-Kowszyk
W. Kamiński
Download PDF Download RIS Download Bibtex

Abstract

Analogy and language contact represent endogenous and exogenous factors of language change. Although both processes have been discussed in the realm of Arabic dialectology, they are usually treated as two unrelated scenarios. The central question that this study posits is whether those are two functionally independent phenomena, or they can operate synergetically. The primary focus of this paper is two typologically distinct Jewish dialects, i.e. sedentary Gabes (Southern Tunisia), and exhibiting numerous Bedouin features Wad-Souf (Eastern Algeria). Based on new data obtained from fieldwork, this paper accounts for five cases of grammar evolution within verb morphology and syntax through the lens of analogy and language contact. It raises the possibility that under certain circumstances, language change can occur at the intersection of endogenous and exogenous factors.
Go to article

Authors and Affiliations

Wiktor Gębski
1
ORCID: ORCID

  1. University of Cambridge, United Kingdom
Download PDF Download RIS Download Bibtex

Abstract

Landslide is a common geological disaster which causes huge losses to people’s properties and national economic development. How to prevent and control landslides has become an important issue. This article introduces the geological and geographical environment of the landslide body, analyzes the basic characteristics of the landslide, calculates the landslide stability based on the ultimate equilibrium theory-based transfer coefficient method, discusses the development trend of the landslide and comes up with corresponding control schemes by taking the landslide body of Black Bovine Cave Copper Ore Mining & Beneficiation Project as example. It is found that the control scheme – “anti-slide pile + retraining wall + baffle + anchor cable” can be used to effectively prevent and control the geological disaster according to calculation. The study results can provide a reference for landslide body control.
Go to article

Authors and Affiliations

Hanhui Wu
1
ORCID: ORCID

  1. Civil Engineering, School of Civil Engineering, Chongqing Chemical Industry Vocational College, 400020 Chongqing, China
Download PDF Download RIS Download Bibtex

Abstract

In the paper an alternative method for increasing punching shear resistance of the flat slabs from lightweight aggregate concrete by means of hidden steel fibre reinforced capital was presented. Previous experimental studies demonstrated that the addition of steel fibres to concrete allows for increase in the punching shear resistance of flat slab. Steel fibres modify the tensile strength of concrete, which translates into increased ductility of the material. The results of the experimental investigations were presented, the aim of which was to assess the effectiveness of the proposed solution. For economic and technological reasons, a hidden capital of a height equal to half of the slabs depth was made so that the top reinforcement could be installed later. It was found that presented solution allowed to increase the load carrying capacity by about 36% with respect to the control element, made entirely of lightweight aggregate concrete.

Go to article

Authors and Affiliations

M. Gołdyn
T. Urban
Download PDF Download RIS Download Bibtex

Abstract

The aim of the study was to develop a practical approach to parametric shaping of spatial steel rod structures formed based on a hyperbolic paraboloid. This design approach was realized by application of designing tools working in environment of Rhinoceros 3D, that is its plug-in Grasshopper for geometric modelling and Karamba 3D for structural analysis. The goal of this research was to elaborate an universal scripts in order to create rod structures‘ models of various forms and grid patterns, as well as evaluating their structural behaviour dependently on various boundary conditions. The optimisation criterion was the minimum mass and deflection. Several proposals of coverings by means of single layer grid structures were presented and analysed to choose the best solution. The rod structures generated based on a hyperbolic paraboloid turned out to be structures with good static properties, so may be an interesting proposals to cover large areas.

Go to article

Authors and Affiliations

J. Dzwierzynska
Download PDF Download RIS Download Bibtex

Abstract

The current design codes recommend designing the building structures based on the assumption avoiding the disproportionate to the initial cause damage during accidental situation. As a main strategy to mitigate a progressive collapse an alternative load path method is recommended. Flush and extended bolted end-plate joint to connect beam-to-column were experimentally tested. Hierarchical validation of joint FEM models based on experimental test results were performed. The numerical dynamic analysis by finite element method of selected steel frame under column loss scenario is presented. The planar 2D model of frame were used. Shell elements for beams and columns and solid elements for joints were employed respectively. Nonlinear material and geometry were applied in the analysis. Johnson-Cook model was used to describe the change of steel parameters by dynamic Increase Factor (DIF). The Rayleigh model to include the damping effects in the analysis was used. The dynamic analysis was performed with the use of Abaqus/Explicit module. Main conclusion of presented research it that to achieve the required level of robustness, bolted beam-to-column joints with extended end-plate of thickness more than 15 mm should be used.
Go to article

Authors and Affiliations

Damian Kukla
1
ORCID: ORCID
Aleksander Kozlowski
1
ORCID: ORCID

  1. Rzeszów University of Technology, Faculty of Civil and Environmental Engineering and Architecture, Poznanska 2, 35-084 Rzeszów, Poland
Download PDF Download RIS Download Bibtex

Abstract

In recent years, we have been able to observe a dynamic development of MCDA (multi-criteria decision analysis) methods, which have become widely used in various sectors, including construction. These methods are characterised by simplicity and one of their key advantages is their simple modelling of non-linear dependencies within decision problems and their analysis under the conditions of incomplete, uncertain and hard-to-measure information. The universality and simple use of these methods does not, however, free the decision-maker from the necessity to adopt the proper approach to modelling and analysing specific decision problems. To highlight the fact that it is the character of the problem that should determine the selection of the method of analysing it and not the other way around, the authors assessed the AHP (Analytic Hierarchy Process) and the ANP (Analytic Network Process) method in terms of verifying the impact of the different decision model structures on analysis outcomes and analysed their sensitivity to input data changes. This analysis was based on the example of selecting a telecommunications tower footing reinforcement alternative. The findings confirmed the significant impact of decision model structure on the ranking of the analysed alternatives.
Go to article

Authors and Affiliations

Bartłomiej Szewczyk
1
ORCID: ORCID
Grzegorz Śladowski
1
ORCID: ORCID
Kamil Ratoń
2
ORCID: ORCID

  1. PhD., Eng., Cracow University of Technology, Faculty of Civil Engineering, 24 Warszawska Street, 31-155 Cracow, Poland
  2. MSc., Eng., PIB Constructor, 100/104 Balicka Street, 30-149 Cracow, Poland
Download PDF Download RIS Download Bibtex

Abstract

The effect of large injection rates on the steady laminar compressible boundary layer in the front stagnation-point region of a rotating sphere with a magnetic field has been studied. The effect of variable gas properties, non-unity Prandtl number and viscous dissipation are included in the analysis. The nonlinear coupled ordinary differential equations governing the flow are first linearized using the quasilinearization technique, and the resulting system of linear equations are then solved using an implicit finite-difference scheme with non-uniform step size. For large injection rates, analytical expressions for the surface shear stresses in the longitudinal and rotating directions and the surface heat transfer are also obtained using an approximate method. For large injection rates, the surface heat transfer tends to zero, but the surface shear stresses in the longitudinal and rotating directions remain finite but small. The surface shear stresses and the surface heat transfer decrease with increasing rate of injection, but they increase with the magnetic field and the rotation parameter. The magnetic field or the rotation parameter induces an overshoot in the longitudinal velocity profile and the magnitude of the velocity overshoot increases significantly with the rotation parameters and the injection parameter. The location of the dividing streamline moves away from the boundary with increasing injection rate, but it moves towards the boundary with increasing magnetic and rotation parameters.
Go to article

Authors and Affiliations

Mahesh Kumari
Girishwar Nath
Download PDF Download RIS Download Bibtex

Abstract

Due to the ongoing climate change, the issues currently in focus are the reduction of CO2 emissions into the atmosphere and sustainable construction. The search for ecological alternatives to traditional building structures that will reduce a building’s carbon footprint seems to be a desirable direction of modern construction development. At present, the first projects of office buildings that use cross-laminated timber as the main construction material are being completed, which can have a positive impact not only on the environment but also on the users of the building.
Go to article

Authors and Affiliations

Aleksander Janicki
1
ORCID: ORCID

  1. Cracow University of Technology, Faculty of Architecture
Download PDF Download RIS Download Bibtex

Abstract

Building upon Gasiorowska and Zaleskiewicz's (2021, 2023), we explored how a control threat and attachment style influence social relationship preferences. This experiment aimed to investigate how experiencing a control threat affects individuals with secure, anxious, and avoidant attachment patterns when they can choose between seeking assistance from the market, asking a close person for help, or coping with the situation alone. Participants with different attachment styles were randomly assigned to either the lack of control condition ( n = 290) or the having control condition ( n = 277). Individuals with an anxious attachment were more inclined to choose the market-exchange option and less likely to select the agentic and communal options when faced with a control threat. Meanwhile, those with an avoidant attachment exhibited a higher tendency to choose the agentic option, while their preference for noncontingent help decreased after exposure to the control threat. Surprisingly, secure attachment individuals showed an increased preference for noncontingent help and decreased preferences for market exchange and self-reliance when exposed to the control threat compared to when they had control. These findings suggest that participation in market relationships may meet vital psychological needs and serve as a safeguard against attachment insecurities.
Go to article

Authors and Affiliations

Agata Gasiorowska
1
ORCID: ORCID
Tomasz Zaleskiewicz
1
ORCID: ORCID

  1. SWPS University SWPS University, Wrocław, Poland
Download PDF Download RIS Download Bibtex

Abstract

We describe the spatial variability of snow accumulation on three selected glaciers in Spitsbergen (Hansbreen, Werenskioldbreen and Aavatsmarkbreen) in the winter seasons of 1988/89, 1998/99 and 2001/2002 respectively. The distribution of snow cover is determined by the interrelationships between the direction of the glacier axes and the dominant easterly winds. The snow distribution is regular on the glaciers located E-W, but is more complicated on the glaciers located meridionally. The western part of glaciers is more predisposed to the snow accumulation than the eastern. This is due to snowdrift intensity. Statistical relationships between snow accumulation, deviation of accumulation from the mean values and accumulation variability related to topographic parameters such as: altitude, slope inclination, aspect, slope curvature and distance from the edge of the glacier have been determined. The only significant relations occured between snow accumulation and altitude (r = 0.64-0.91).

Go to article

Authors and Affiliations

Mariusz Grabiec
Jan Leszkiewicz
Piotr Głowacki
Jacek Jania

This page uses 'cookies'. Learn more