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Abstract

A buckling analysis of temperature-dependent embedded plates reinforced by single-walled carbon nanotubes (SWCNTs) subjected to a magnetic field is investigated. The SWCNTs are distributed as uniform (UD) and three types of functionally graded nanotubes (FG), in which the material properties of the nano-composite plate are estimated based on the mixture rule. The surrounding temperature-dependent elastic medium is simulated as Pasternak foundation. Based on the orthotropic Mindlin plate theory, the governing equations are derived using Hamilton's principle. The buckling load of the structure is calculated based on an exact solution by the Navier method. The influences of elastic medium, magnetic field, temperature and distribution type, and volume fractions of SWCNT are shown on the buckling of the plate. Results indicate that CNT distribution close to the top and bottom are more efficient than that distributed near the mid-plane for increasing the stiffness of the plates.

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Authors and Affiliations

R. Kolahchi
M. Esmailpour
M. Safari
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Abstract

The aim of this paper is to present an assessment of the slip influence on the deflection of the steel plate-concrete composite beams, which are a new type of a design concept. The proposed method is based on the procedure included in the PN-EN 1992-1-1, which has been modified with taking into consideration interface slip. The theoretical analysis was verified by experimental studies.

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Authors and Affiliations

D. Kisała
K. Furtak
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Abstract

The subject of the analytical and experimental studies therein is of two metal seven-layer beam - plate bands. The first beam - plate band is composed of a lengthwise trapezoidally corrugated main core and two crosswise trapezoidally corrugated cores of faces. The second beam - plate band is composed of a crosswise trapezoidally corrugated main core and two lengthwise trapezoidally corrugated cores offaces. The hypotheses of deformation of a normal to the middle surface of the beams after bending are formulated. Equations of equilibrium are derived based on the theorem of minimum total potential energy. Three-point bending of the simply supported beams is theoretically and experimentally studied. The deflections of the two beams are determined with two methods, compared and presented.

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Authors and Affiliations

E. Magnucka-Blandzi
P. Paczos
P. Wasilewicz
A. Wypych
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Abstract

The paper presents a certain way which determines the critical buckling force for a micro-heterogeneous FGM plate band. A stiffness matrix of an individual cell of such band, different for various cells, has been determined. The obtained matrix can also be treated as a variable stiffness matrix of a “superelement” in the Finite Element Method. A computational algorithm for the critical force as well as the way of testing of its correctness has also been presented. The results obtained for various support conditions have been compared to the values known from the literature. The influence of the number of cells on the critical buckling force has been investigated.

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Authors and Affiliations

M. Chalecki
G. Jemielita
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Abstract

The inverse solution to the heat flux identification during the vertical plate cooling in air has been presented. The developed solution allowed to separate the energy absorbed by the chamber due to radiation from the convection heat losses to air. The uncertainty tests were carried out and the accuracy of the solution has been estimated at a level of 1%-5% depending on the boundary condition model. The inverse solution was obtained for the temperature measurements in the vertical plate. The stainless-steel plate was heated to 950°C and then cooled in the chamber in air only to about 30°C. The identified heat transfer coefficient was compared with the Churchill and Chu model. The solution has allowed to separate the radiation heat losses and to determine the Nusselt number values that stay in good agreement with the Churchill and Chu model for a nearly steady-state air flow for the plate temperature below 100°C.
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Authors and Affiliations

B. Hadała
1
ORCID: ORCID
Z. Malinowski
1
ORCID: ORCID
A. Gołdasz
2
ORCID: ORCID
A. Cebo-Rudnicka
1
ORCID: ORCID

  1. AGH University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, Department of Heat Engineering and Environment Protection, al. Mickiewicza 30, 30-059 Kraków, Poland
  2. AGH University of Science and Technology, Faculty of Energy and Fuels, al. Mickiewicza 30, 30-059 Kraków, Poland
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Abstract

This article investigates the solution of exponentially graded (EG) thick rectangular plates resting on two-parameter elastic foundations according to a trigonometric plate theory (TPT). This theory includes the effect of both shear and normal strains thickness without needing to any shear correction factor. The displacement fields contains initial terms of a power series across plate thickness as well as additional trigonometric terms. The material properties of plate is graded such that Lamé’s coefficients convert exponentially in a given constant orientation. Equilibrium equations according to the EG plate resting on Pasternak’s foundations are derived. The solution is obtained by using Navier’s technique. Numerical results for the EG thick plate on elastic foundations are presented, and compared with those available in the literature. The influences of Winkler’s and Pasternak’s parameters, side-to-thickness ratio, inhomogeneity parameter and aspect ratio on the bending responses of EG plates are investigated.
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Authors and Affiliations

Ashraf M. Zenkour
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Abstract

The paper presents the response of a three-layered annular plate with damaged laminated facings to the loads acting in their planes. The presented problem concerns the analysis of the combination of global plate failure in the form of buckling with the local micro defects, like fibre or matrix cracks, located in the laminas. The plate structure consists of thin laminated, fibre-reinforced composite facings and a thicker foam core. The matrix and fibre cracks of facings laminas can be transversally symmetrically or asymmetrically located in plate structure. Critical static and dynamic stability analyses were carried out solving the problem numerically and analytically. The numerical results show the static and dynamic stability state of the composite plate with different combinations of damages. The final results are compared with those for undamaged structure of the plate and treated as quasi-isotropic ones. The analysed problem makes it possible to evaluate the use of the non-ideal composite plate structure in practical applications.

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Bibliography

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[22] D. Pawlus. Dynamic response of three-layer annular plate with damaged composite facings. Archive of Mechanical Engineerig, 65(1):1: 83–105, 2018. doi: 10.24425/119411.
[23] D. Pawlus. Critical state evaluation of three-layered annular plates with symmetry and asymmetry damaged composite structure. Mechcomp 3 – 3rd International Conference on Mechanics of Composites, Bologna, Italy, 4–7 July, 2017.
[24] A. Muc. Mechanics of Fibrous Composites. Księgarnia Akademicka, Kraków, 2003 (in Polish).
[25] C. Volmir. Nonlinear Dynamic of Plates and Shells. Science, Moskwa, 1972 (in Russian).
[26] J. German. Fundamentals of Mechanics of Fibrous Composites. Politechnika Krakowska, Kraków, 1996 (in Polish).
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[30] D. Pawlus. Solution to the problem of axisymmetric and asymmetric dynamic instability of three-layered annular plates. Thin-Walled Structures, 49(4):660–668, 2011. doi: 10.1016/j.tws.2010.09.013.
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Authors and Affiliations

Dorota Pawlus
1

  1. Faculty of Mechanical Engineering and Computer Science, University of Bielsko-Biala, Poland.
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Abstract

The paper presents the solutions, calculation results and dynamic observations of three-layers, annular plate with thick core subjected to increasing in time load. The presented solutions use approximate methods: orthogonalization method and finite difference method in analytical and numerical solution of the problem, and finite element method. The observed phenomenon of the reduction of critical load values of the plates, in which the buckling mode is not global and there are different additional deflections of respective plate layers was comprehensively analysed in order to evaluate the critical state and supercritical plate behaviour. The critical deformation could have a form with strong deformation in the region of the loaded plate edge. The observation of the dynamic behaviour of plates, which buckling modes have circumferential waves is an important element of the analysis. Presented in this work the analytical and numerical solution to the problem of dynamic plate deflection was generalized on the case of plates with buckling waves in circumferential direction.

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Bibliography

[1] A. Valera-Medina, A. Giles, D. Pugh, S. Morris, M. Pohl, and A. Ortwein. Investigation of combustion of emulated biogas in a gas turbine test rig. Journal of Thermal Science, 27:331–340, 2018. doi: 10.1007/s11630-018-1024-1.
[2] K. Tanaka and I. Ushiyama. Thermodynamic performance analysis of gas turbine power plants with intercooler: 1st report, Theory of intercooling and performance of intercooling type gas turbine. Bulletin of JSME, 13(64):1210–1231, 1970. doi: 10.1299/jsme1958.13.1210.
[3] H.M. Kwon, T.S. Kim, J.L. Sohn, and D.W. Kang. Performance improvement of gas turbine combined cycle power plant by dual cooling of the inlet air and turbine coolant using an absorption chiller. Energy, 163:1050–1061, 2018. doi: 10.1016/j.energy.2018.08.191.
[4] A.T. Baheta and S.I.-U.-H. Gilani. The effect of ambient temperature on a gas turbine performance in part load operation. AIP Conference Proceedings, 1440:889–893, 2012. doi: 10.1063/1.4704300.
[5] F.R. Pance Arrieta and E.E. Silva Lora. Influence of ambient temperature on combined-cycle power-plant performance. Applied Energy, 80(3):261–272, 2005. doi: 10.1016/j.apenergy.2004.04.007.
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[7] M.A.A. Alfellag: Parametric investigation of a modified gas turbine power plant. Thermal Science and Engineering Progress, 3:141–149, 2017. doi: 10.1016/j.tsep.2017.07.004.
[8] J.H. Horlock and W.A. Woods. Determination of the optimum performance of gas turbines. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 214:243–255, 2000. doi: 10.1243/0954406001522930.
[9] L. Battisti, R. Fedrizzi, and G. Cerri. Novel technology for gas turbine blade effusion cooling. In: Proceedings of the ASME Turbo Expo 2006: Power for Land, Sea, and Air. Volume 3: Heat Transfer, Parts A and B. pages 491–501. Barcelona, Spain. May 8–11, 2006. doi: 10.1115/GT2006-90516.
[10] F.J. Wang and J.S. Chiou. Integration of steam injection and inlet air cooling for a gas turbine generation system. Energy Conversion and Management, 45(1):15–26, 2004. doi: 10.1016/S0196-8904 (03)00125-0.
[11] Z. Wang. 1.23 Energy and air pollution. In I. Dincer (ed.): Comprehensive Energy Systems, pp. 909–949. Elsevier, 2018. doi: 10.1016/B978-0-12-809597-3.00127-9.
[12] Z. Khorshidi, N.H. Florin, M.T. Ho, and D.E. Wiley. Techno-economic evaluation of co-firing biomass gas with natural gas in existing NGCC plants with and without CO$_2$ capture. International Journal of Greenhouse Gas Control, 49:343–363, 2016. doi: 10.1016/j.ijggc.2016.03.007.
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[18] M.N. Khan, T.A. Alkanhal, J. Majdoubi, and I. Tlili. Performance enhancement of regenerative gas turbine: air bottoming combined cycle using bypass valve and heat exchanger—energy and exergy analysis. Journal of Thermal Analysis and Calorimetry. 144:821–834, 2021. doi: 10.1007/s10973-020-09550-w.
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[29] T.K. Ibrahim, F. Basrawi, O.I. Awad, A.N. Abdullah, G. Najafi, R. Mamat, and F.Y. Hagos. Thermal performance of gas turbine power plant based on exergy analysis. Applied Thermal Engineering, 115:977–985, 2017. doi: 10.1016/j.applthermaleng.2017.01.032.
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Authors and Affiliations

Dorota Pawlus

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Abstract

In this study, the vibration analysis of fully and partially treated laminated composite Magnetorheological (MR) fluid sandwich plates has been investigated experimentally. The natural frequencies of fully and partially treated laminated composite MR fluid sandwich plates have been measured at various magnetic field intensities under two different boundary conditions. The variations of natural frequencies with applied magnetic field, boundary conditions and location ofMRfluid pocket have been explored. Further, a comparison of natural frequencies of fully and partially treated MR fluid sandwich structure has been made at various magnetic field intensities.

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Authors and Affiliations

R. Manoharan
R. Vasudevan
P. Edwin Sudhagar
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Abstract

In the paper, the authors present the shakedown analysis of the plate structures pre-loaded beyond the elastoplastic range. Two cases of loading are considered, namely: the structure is subjected to the action of two independent sets ofloads with constant points of application or one parameter set of loads moves slowly according to an a priori described program. As a result, the safe loading boundary or the shakedown load parameter are calculated, respectively, by means of the finite element method (FEM). Three examples confirmed the effectiveness of the proposed algorithms of analysis.
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Authors and Affiliations

Czesław Cichoń
Paweł Stąpór
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Abstract

The two-variable refined plate theory is used in this paper for the analysis of thick plates resting on elastic foundation. This theory contains only two unknown parameters and predicts parabolic variation of transverse shear stresses. It satisfies the zero traction on the plate surfaces without using shear correction factor. Using the principle of minimum potential energy, the governing equations for simply supported rectangular plates resting on Winkler elastic foundation are obtained. The Navier method is adopted for solution of obtained coupled governing equations, and several benchmark problems under various loading conditions are solved by present theory. The comparison of obtained results with other common theories shows the excellent efficiency of this theory in modeling thick plates resting on elastic foundation. Also, the effect of foundation modulus, plate thickness and type of loading are studied and the results show that the deflections are decreased by increasing the foundation modulus and plate thickness.

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Bibliography

[1] A. Valera-Medina, A. Giles, D. Pugh, S. Morris, M. Pohl, and A. Ortwein. Investigation of combustion of emulated biogas in a gas turbine test rig. Journal of Thermal Science, 27:331–340, 2018. doi: 10.1007/s11630-018-1024-1.
[2] K. Tanaka and I. Ushiyama. Thermodynamic performance analysis of gas turbine power plants with intercooler: 1st report, Theory of intercooling and performance of intercooling type gas turbine. Bulletin of JSME, 13(64):1210–1231, 1970. doi: 10.1299/jsme1958.13.1210.
[3] H.M. Kwon, T.S. Kim, J.L. Sohn, and D.W. Kang. Performance improvement of gas turbine combined cycle power plant by dual cooling of the inlet air and turbine coolant using an absorption chiller. Energy, 163:1050–1061, 2018. doi: 10.1016/j.energy.2018.08.191.
[4] A.T. Baheta and S.I.-U.-H. Gilani. The effect of ambient temperature on a gas turbine performance in part load operation. AIP Conference Proceedings, 1440:889–893, 2012. doi: 10.1063/1.4704300.
[5] F.R. Pance Arrieta and E.E. Silva Lora. Influence of ambient temperature on combined-cycle power-plant performance. Applied Energy, 80(3):261–272, 2005. doi: 10.1016/j.apenergy.2004.04.007.
[6] M. Ameri and P. Ahmadi. The study of ambient temperature effects on exergy losses of a heat recovery steam generator. In: Cen, K., Chi, Y., Wang, F. (eds) Challenges of Power Engineering and Environment. Springer, Berlin, Heidelberg, 2007. doi: 10.1007/978-3-540-76694-0_9.
[7] M.A.A. Alfellag: Parametric investigation of a modified gas turbine power plant. Thermal Science and Engineering Progress, 3:141–149, 2017. doi: 10.1016/j.tsep.2017.07.004.
[8] J.H. Horlock and W.A. Woods. Determination of the optimum performance of gas turbines. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 214:243–255, 2000. doi: 10.1243/0954406001522930.
[9] L. Battisti, R. Fedrizzi, and G. Cerri. Novel technology for gas turbine blade effusion cooling. In: Proceedings of the ASME Turbo Expo 2006: Power for Land, Sea, and Air. Volume 3: Heat Transfer, Parts A and B. pages 491–501. Barcelona, Spain. May 8–11, 2006. doi: 10.1115/GT2006-90516.
[10] F.J. Wang and J.S. Chiou. Integration of steam injection and inlet air cooling for a gas turbine generation system. Energy Conversion and Management, 45(1):15–26, 2004. doi: 10.1016/S0196-8904 (03)00125-0.
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Authors and Affiliations

Jafar Rouzegar
Reza Abdoli Sharifpoor

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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 formulation of a plate finite element with so called ‘physical’ shape functions is revisited. The derivation of the ‘physical’ shape functions is based on Hencky-Bollé theory of moderately thick plates. The considered finite element was assessed in the past, and the tests showed that the solution convergence was achieved in a wide range of thickness to in-plane dimensions ratios. In this paper a holistic correctness assessment is presented, which covers three criteria: the ellipticity, the consistency and the inf-sup conditions. Fulfilment of these criteria assures the existence of a unique solution, and a stable and optimal convergence to the correct solution. The algorithms of the numerical tests for each test case are presented and the tests are performed for the considered formulation. In result it is concluded that the finite element formulation passes every test and therefore is a good choice for modeling plate structural elements regardless of their thickness.

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Authors and Affiliations

W. Gilewski
M. Sitek
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Abstract

This article deals with the problem of determining the resistance of end-plate connections. A nonlinear FEM model of the joint was constructed in order to predict its carrying capacity. A standard code procedure was done as well. The analyses have been done to assess atypical end-plate joints designed and constructed as a part of roof structures.

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Authors and Affiliations

K. Żółtowski
P. Kalitowski
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Abstract

The purpose of this study is to find the value of the discharge coefficient (Cd) on a sieve with a circular perforated plate so that it can be used for application in the field. The method used is to make a physical model test of the screen weir in the laboratory with a width of 40 cm and a length of 797 cm, then the screen is made variations in the diameter of the hole 6, 8, 10 and 12 mm, flowrate Q = 453–4 481 cm3∙s–1 and the slope of the screen θ = 20–45°. The result was quite ef-fective, the sediment did not enter above the screen and did not clog the screen even the catch was quite good about 80% of the screen rods. The discharge coefficient (Cd) is directly proportional to the square value of the number Froude (Fr), the slope of the screen (θ) and the ratio of distance, diameter of the screen (a:d) and inversely proportional to the value of the specific energy square (E). From modelling the average value of the discharge coefficient (Cd) between 0.1–2.75 with NSE = 0.71, MAE = 0 and RMSE = 0.12.

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Authors and Affiliations

Nanang S. RizalL
Mohammad Bisri
Pitojo T. Juwono
Very Dermawan
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Abstract

The flow of the investigated fluid in a measuring system of a rheometer – a capillary or a slit between rotating parts – may be disturbed by anisotropic behavior of the fluid near the wall. This phenomenon, so-called wall slip, often takes place in concentrated suspensions and solutions of linear polymers and introduces experimental errors to measurement results. There are methods of correction of these errors in the case of capillary and coaxial cylinders measuring systems. In the cone and plate system the correction seems to be more difficult because the width of the gap between cone and plate changes along the radius and thus the influence of the wall slip on the shear stress varies along the radius in an unpredictable and complicated manner. This dependency of the shear stress on the distance from the axis underlies the presented method of correction of experimental results obtained in the cone and plate system. The method requires several series of measurements of shear stress vs. shear rate performed using one measuring set, at various degrees of filling the gap.

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Authors and Affiliations

Tomasz Kiljański
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Abstract

Silver coatings have a very high reflection ability. To avoid their darkening from the hydrogen sulphide in the air, a thin layer of heat-resistant colorless lacquer is applied to the coatings. Silver plating is mainly used in jewelery, optics, electronics and electrical engineering. Depending on their application the thickness of the layer may vary from 2 to 24 μm. It can be done in several ways: chemical, electrochemical, contact, etc. The most common way of silver plating is the electrochemical deposition using cyanide and non-cyanide electrolytes. The cyanide electrolytes produce light, fine crystalline, dense and plastic coatings upon silver-plating. Usually silver coatings are applied with copper or nickel intermediate layer. In order to improve the de-oxidation of the aluminum surface new chemical treatment in acid – alkaline solution was applied. Our previous research shows that the presence of diamond nanoparticles in the electrolyte increase the metal deposition. Samples were prepared from electrolyte containing 10 g/l diamond nanoparticles. Their properties were compared to the properties of reference samples. The diamonds were obtained by detonation synthesis. The aim of this study is to obtain electrochemically deposited silver layer with high density, adhesion and electric conductivity on aluminum alloys substrate. The coatingwas directly plated without intermediate layer. Non-cyanide electrolyte composition and electrochemical parameters were determined in order to produce Ag coatings on Al alloy substrate without intermediate layer. The coating is with good adhesion, density and thickness of 14-23 μm.

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Authors and Affiliations

R. Valov
V. Petkov
S. Valkano
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Abstract

To improve the mechanical performance of BiTe-based thermoelectric modules, this study applies anti-diffusion layers that inhibit the generation of metal intercompounds and an electroless nickel/electrode palladium/mission gold (ENEPIG) plating layers to ensure a stable bonding interface. If a plated layer is formed only on BiTe-based thermoelectric, the diffusion of Cu in electrode substrates produces an intermetallic compound. Therefore, the ENEPIG process was applied on the Cu electrode substrate. The bonding strength highly increased from approximately 10.4 to 16.4 MPa when ENEPIG plating was conducted to the BiTe-based thermoelectric element. When ENEPIG plating was performed to both the BiTe-based thermoelectric element and the Cu electrode substrate, the bonding strength showed the highest value of approximately 17.6 MPa, suggesting that the ENEPIG process is effective in ensuring a highly reliable bonding interface of the BiTe-based thermoelectric module.
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Bibliography

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Authors and Affiliations

Subin Kim
1
ORCID: ORCID
Sung Hwa Bae
2
ORCID: ORCID
Injoon Son
1
ORCID: ORCID

  1. Kyungpook National University, Department of Materials Science and Metallurgical Engineering, Daegu, Republic of Korea
  2. Kyushu University Graduate School of Engineering, Department of Materials Process Engineering, Fukuoka, Japan
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Abstract

Effect of annealing treatment on deep drawing behavior of hot-rolled Q235 carbon steel/410/304 stainless steel three-layer composite plate was investigated. Deep drawability of the unannealed composite plates exhibits a sharp difference for various contact surfaces with the die. The limit drawing ratio (LDR) of the composite plate with the carbon steel contacting the die is 1.75, while it is 1.83 with the stainless steel contacting the die due to the different mechanical responses to the tensile stress at the corner of the die. After annealing at 900°C for 2 h, however, the deep drawabilities of the composite plates both for various contact surfaces with the die are significantly improved and becomes almost identical, which are attributed to the stress relief, the enhanced ductility and the improved interface bonding strength of the hot-rolled component plates during annealing.
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Authors and Affiliations

Zehua Lv
1 2 3
Zhixiong Zhang
1 2 3
Jianchao Han
1 2 3
Tao Wang
1 2 3
ORCID: ORCID

  1. Taiyuan University of Technology, College of Mechanical and Vehicle Engineering, Taiyuan 030024, PR China
  2. Taiyuan University of Technology, Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment, Ministry of Education, Taiyuan 030024, PR China
  3. Taiyuan University of Technology, Tyut-Uow Joint Research Centre, Taiyuan 030024, PR China
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Abstract

The Ti-Zr and Ti-Zr/sol-gel were used as pretreatment layers before the electroless nickel coating on AM60B magnesium alloy. Scanning Electron Microscopy was employed to investigate the surface morphology of the pretreated layers and applied electroless coatings. Chemical analysis of the Ti-Zr layer, and nickel coatings was done using the Energy-Dispersive X-ray Spectroscopy. Moreover, the X-ray Diffraction and Atomic Force Microscopy methods were utilized to evaluate the microstructure and surface roughness of the electroless coatings, respectively. Electrochemical Impedance Spectroscopy was employed to study the corrosion behavior of Ni-P coatings. The results show that Ti-Zr layer has structural cracks, and the sol-gel film was covered all cracks entirely. The cauliflower-like electroless nickel coating was applied on both mentioned pretreated layers. The cross-sectional images revealed the higher thickness for the electroless coating on Ti-Zr/sol-gel layer, probably due to a large number of Ni nucleation centers. The EIS results demonstrate that the electroless coating on Ti-Zr/sol-gel has high corrosion protection and microhardness value.
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Authors and Affiliations

Zhale Nazari
1
ORCID: ORCID
Davod Seifzadeh
1
ORCID: ORCID
Zahra Rajabalizadeh
1
ORCID: ORCID

  1. University of Mohaghegh Ardabili, Faculty of Science, Corrosion and Industrial Electrochemistry Research Laboratory, Ardabil-Iran
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Abstract

This work deals with the analysis of elasto-plastic post-buckling state of rectangular laminated plates subjected to combined loads, such as uniform compression and shear. The plates are built of specially orthotropic symmetrical layers. The analysis is carried out on the basis of nonlinear theory of orthotropic plates involving plasticity. The solution can be obtained in the analytical-numerical way using Prandtl-Reuss equations. The preliminary results of numerical calculations are also presented in figures.
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Authors and Affiliations

Ryszard Grądzki
Katarzyna Kowal-Michalska
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Abstract

The problem of setting out in civil engineering applications has been addressed in the literature for a long time. However, technological development has provided researchers with an opportunity of having other procedures in line with modern techniques in surveying sciences. One of the most important procedures in erecting steel structures, bridges, and precast columns of a building is the accurate placement of the anchorage system in concrete. The traditional method for staking out anchor bolts relies on sight rails, string lines, and tape measure. The precision of this art depends not only on the accuracy of observed offset distances during layout operations but also on the centerline of the anchoring template itself. Nowadays, the process of designing structures is executed using software that can perform a digital plan in CAD environment, where the coordinates of each anchor bolt can be defined. This research presents an accurate approach of positioning anchor bolts based on the second problem in surveying and total station. Error analysis and field application are described to evaluate the performance of the proposed method. However, the results indicate that the developed technique increases productivity, reduces the cost, and improves the positional accuracy.

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Authors and Affiliations

M. Habib
A. Malkawi
M. Awwad
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Abstract

Given its high efficiency, low emissions and multiple fuelling options, the solid oxide fuel cells (SOFC) offer a promising alternative for stationary power generators, especially while engaged in micro-combined heat and power (μ-CHP) units. Despite the fact that the fuel cells are a key component in such power systems, other auxiliaries of the system can play a critical role and therefore require a significant attention. Since SOFC uses a ceramic material as an electrolyte, the high operating temperature (typically of the order of 700–900°C) is required to achieve sufficient performance. For that reason both the fuel and the oxidant have to be preheated before entering the SOFC stack. Hot gases exiting the fuel cell stack transport substantial amount of energy which has to be partly recovered for preheating streams entering the stack and for heating purposes. Effective thermal integration of the μ-CHP can be achieved only when proper technical measures are used. The ability of efficiently preheating the streams of oxidant and fuel relies on heat exchangers which are present in all possible configurations of power system with solid oxide fuel cells. In this work a compact, fin plate heat exchanger operating in the high temperature regime was under consideration. Dynamic model was proposed for investigation of its performance under the transitional states of the fuel cell system. Heat exchanger was simulated using commercial modeling software. The model includes key geometrical and functional parameters. The working conditions of the power unit with SOFC vary due to the several factors, such as load changes, heating and cooling procedures of the stack and others. These issues affect parameters of the incoming streams to the heat exchanger. The mathematical model of the heat exchanger is based on a set of equations which are simultaneously solved in the iterative process. It enables to define conditions in the outlets of both the hot and the cold sides. Additionally, model can be used for simulating the stand-alone heat exchanger or for investigations of a semiadiabatic unit located in the hotbox of the μ-CHP unit.
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Authors and Affiliations

Konrad Motyliński
Jakub Kupecki
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Abstract

The paper describes issues related to pressure drop that accompanies the phenomenon of maldistribution of working fluid between the channels of a model minichannel plate heat exchanger. The research concerns a single exchanger’s plate containing 51 (in every geometry) parallel rectangular minichannels of hydraulic diameters 461 μm, 571 μm, 750 μm, and 823 μm. In addition, more complex geometry has been investigated, equipped with additional diagonal channels (so called extended geometry). The moment of the liquid phase transition through the heat exchanger was recorded at the flow rates ranging from 0.83 g/s to 13.33 g/s in the inlet manifold. The paper discusses the total pressure drop as a function of the flow rate and the characteristic dimension of minichannels, as well as the pressure drop as a function of the time of the fluid passage through the main part of the measuring section in which measurements were done. The resulting profiles correlate with the images of the flow distribution between channels recorded using the fast shutter speed camera, that allows to draw a further conclusions about the specifics of the maldistribution process. The impact of the total pressure drop on the actual range of optimum operating conditions of the heat exchanger was analyzed.
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Authors and Affiliations

Michał Klugmann
Paweł Dąbrowski
Dariusz Mikielewicz

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