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Abstrakt

The results of experimental test of nine thickset reinforced concrete slabs in punching are presented in the this paper. The aim of the tests was verifi cation of the Eurocode EC 2 procedure, by which the ultimate shear stresses vRd,c depend on the slenderness of the slab. Besides of the performed tests results, the analysis of the foreign investigation of the fundaments is also included. The test results, as well as other tests, show the correctness of the function assumed in Eurocode 2, which gives correlation between ultimate stresses vRd,c and shear slenderness.

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Autorzy i Afiliacje

T. Urban
M. Gołdyn
J. Krakowski
Ł. Krawczyk

Abstrakt

This paper presents research results of composite tubes filled with self-compacting concrete. The impact of the selected materials and geometric factors on resistance to the vertical shear was evaluated in this study. The resistance of the tested members was compared with recommendations given in Eurocode PN-EN 1994-1-1. From the results obtained in the tests it can be deduced that more parameters should be taken into consideration when determining resistance to the vertical shear in the interface between steel and concrete than PN-EN 1994-1-1 recommends.

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Autorzy i Afiliacje

M. Szadkowska
E. Szmigiera

Abstrakt

The standard PN-EN_1993-1-5:_2008 (Eurocode 3) compared with the standard (PN-B-03200:_1990) used previously in Poland, introduces extended rules referring to the computations of the bearing capacity of the plated structural elements including the shear lag effect. The stress distribution in the width flanges is variable. Therefore in the case of the beam with the shear lag effect cannot be calculated by the classic beam theory.

In this article a comparison of the results of the calculations of forces distribution, stresses and displacement according to the rule presented in PN-EN_1993 and results of the numerical computations for_3D model (using finite element method) is presented. The elastic shear lag effects, the elastic shear lag effects including effects of the plate buckling and the elastic-plastic shear lag effects including the local instabilities were analysed. The calculations were performed for beams with a small and a large span and an influence of stiffeners was analysed.

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Autorzy i Afiliacje

M. Szumigała
K. Ciesielczyk

Abstrakt

The present paper is dedicated to presentation and energy verification of the methods of stabilization the strain energy by penalty coefficients. Verification of the methods is based on the consistency and ellipticity conditions to be satisfied by the finite elements. Three methods of stabilization are discussed. The first does not satisfy the above requirements. The second is consistent but cannot eliminate parasitic energy terms. The third method, proposed by the author, is based on the decomposition of the element stiffness matrix. The method can help to eliminate locking of the finite elements. For two-noded beam element with linear shape functions and exact integration a stabilized free of locking (and elliptical) element is received (equivalent to reduced integration element). Two plate finite elements are analyzed: four-noded rectangular element and DSG triangle. A new method of stabilization with the use of four independent parameters is proposed. The finite elements with this kind of stabilization satisfy the consistency condition. In the rectangular element it was not possible to eliminate one parasitic term of energy which appears during the procedure. For DSG triangle all parasitic terms of energy are eliminated. The penalty coefficients depends on the geometry of the triangle.

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Autorzy i Afiliacje

W. Gilewski

Abstrakt

The paper concerns simulation of fully developed and axially-symmetrical turbulent flow of coarse-dispersive slurry if all solid particles have similar size and shape with particles diameter from 1 mm to 5 mm, solid density from 1045 kg/m^3 to 3000 kg/m^3, and solid concentration by volume from 20% to 40%. The author examines the influence of particle diameter on additional shear stress due to the ‘particles-wall’ interactions for moderate and high solid concentration. The mathematical model was developed using Bagnold's concept, [26] and assumes that the total wall shear stresses are equal to the sum of ‘liquid-wall’ and ‘particles-wall’ shear stresses. The mathematical model was successfully verified with own measurements of frictional head loss in vertical coarse - dispersive slurry flow, named: ‘sand-water’, ‘polystyrene-water’ and ‘pvc-water’, [10], [26]. The mathematical model can predict ‘particles-wall’ shear stress, pressure drop and friction factor for coarse-dispersive turbulent slurry flow in a pipe, [10].

The aim of the paper is to present qualitative and quantitative dependence of solid particle diameter, solid particle density, solid concentration, and Reynolds number for carrier liquid phase on the ‘particles-wall’ shear stress. It is demonstrated that the solid particle diameter plays crucial role in its dependence on the ‘particles-wall’ shear stress. It was proved that in particular flow conditions the ‘particles-wall’ shear stress is much higher compared to the carrier liquid wall shear stress.

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Autorzy i Afiliacje

Artur Bartosik

Abstrakt

Shear walls are the most commonly used lateral load resisting systems in high rises. They have high plane stiffness and strength which can be used to simultaneously resist large horizontal loads while also supporting gravity loads. Hence it is necessary to determine effective and ideal locations of shear walls. Shear wall arrangement must be absolutely accurate, if not, it may cause negative effects instead. In this project, a study has been carried out to determine the effects of additions of shear walls and also the optimum structural configuration of multistory buildings by changing the shear wall locations radically. Four different cases of shear wall positions for G+10 storey buildings have been analyzed by computer application software ETABS. The framed structure was subjected to lateral and gravity loading in accordance with the Indian Standards provision and the results were analyzed to determine the optimum positioning of the shear walls.

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Autorzy i Afiliacje

A. Titiksh
G. Bhatt

Abstrakt

The paper presents the results of an extensive investigation of asphalt concrete specimens with geosynthetic interlayer. The subject of this research is evaluation of influence of geosynthetics interlayer applied to bituminous pavements on interlayer bonding of specimens. The results of the tests proves that when geosynthetic is used, the bonding of interlayer depends mainly on the type of bituminous mixture, the type of geosynthetic, and the type and amount of bitumen used for saturation and sticking of geosynthetic. The amount of bitumen used in order to saturate and fix the geosynthetic significantly changes the interlayer bonding of specimens.

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Autorzy i Afiliacje

P. Zieliński

Abstrakt

The article presents the results of investigation of ultra-strength nanostructured bainitic steel Fe-0.6%C-1.9%Mn-1.8%Si-1.3%Cr-0.7%Mo (in wt. %) subjected to shear and uniaxial compression under high strain rate loading. Steel of microstructure consisted of carbide-free bainite and carbon enriched retained austenite presents a perfect balance of mechanical properties especially strength to toughness ratio. Two retained austenite morphologies exist which controlled ductility of the steel: film between bainite laths and separated blocks. It is well established that the strain induced transformation of carbon enriched retained austenite to martensite takes place during deformation. Shear localisation has been found to be an important and often dominant deformation and fracture mode in high-strength steels at high strain rate. Deformation tests were carried out using Gleeble simulator and Split Hopkinson Pressure Bar. Shear and compression strength were determined and toughness and crack resistance were assessed. Susceptibility of nanostructured bainitic steel to the formation of adiabatic shear bands (ASBs) and conditions of the bands formation were analysed. The results suggest that the main mechanism of hardening and failure at the dynamic shearing is local retained austenite transformation to high-carbon martensite which preceded ASBs formation. In the area of strain localization retained austenite transformed to fresh martensite and then steel capability to deformation and strengthening decreases.

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Autorzy i Afiliacje

J. Marcisz
J. Janiszewski

Abstrakt

The proposition of a method to verify the punching resistance for very large supports based on the EN 1992-1-1 standard is described in this paper. The present standard guidelines for the calculation of the punching resistance for large supports are also summarised. The proposed direct method is compared with other standard methods using an example taken from design practice. This method consists of a direct check of the shear forces at specific locations of the control perimeter with the permissible shear force calculated from the EC2 standard. The method showed very good agreement with the experiment while remaining practical for applications. The method presented takes into account the actual distribution of shear forces in the vicinity of the support, taking into account the influence of non-uniform loads, irregular floor geometry, the concentration of internal forces at the corners of the support and the influence of the stiffness of the head used. The paper provides scientists, engineers, and designers new method (called the direct method) for estimation of the punching load-bearing capacity outside the shear cap.
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Autorzy i Afiliacje

Maciej Grabski
1
ORCID: ORCID
Andrzej Ambroziak
2
ORCID: ORCID

  1. Maciej Grabski Engineering, 94B/1 Leszczynowa Street, 80-175 Gdansk, Poland
  2. Gdansk University of Technology, Faculty of Civil and Environmental Engineering, Gabriela Narutowicza St. 11/12, 80-233 Gdansk, Poland

Abstrakt

In recent years, bridge safety accidents caused by insufficient shear bearing capacity of bridges have attracted increasing attention. The main causes include internal factors such as insufficient bridge section and deterioration of steel bars, as well as external factors, for example, vehicle load surge and improper maintenance. To address this issue to some degree, this article adopts the method of strengthening RC beams with ultra-high performance concrete (UHPC) and conducts parameter analysis using finite element method, taking into consideration the influence of four parameters: reinforcement material, reinforcement thickness, reinforcement length, and reinforcement form on the shear strengthening characteristics of RC rectangular beams. After obtaining the optimal reinforcement plan through parameter analysis, the author applied the research results to an existing bridge with insufficient shear strength. It then turned out that the shear bearing capacity of the reinforced bridge’s inclined section increased by approximately 27.1%. Simple and fast in construction, this reinforcement method is one of the methods that is effective to increase cross-section reinforcement; besides, it features good economic characteristics and applicability.
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Autorzy i Afiliacje

Jiawei Wang
1
ORCID: ORCID
Ziqian Wang
2
Feifei Ying
3
ORCID: ORCID
Haitao Yu
4
ORCID: ORCID

  1. Anhui Polytechnic University, School of Architecture and Civil Engineering, Wuhu City, BeijingMiddle Road, China
  2. Anhui Polytechnic University, School of Architecture[ and Civil Engineering, Wuhu City, Beijing MiddleRoad, China
  3. Anhui Polytechnic University, School of Architecture and Civil Engineering, Wuhu City, Beijing MiddleRoad, China
  4. Heilongjiang Longfeng Highway Engineering Test Co.,LTD, Harbin City, Hexing Road, China

Abstrakt

The aim of the paper is to investigate the shear failure mechanisms in T-shape, single span and simply supported beams exclusively reinforced with longitudinal glass fiber reinforced polymer (GFRP) bars. Usually the critical shear crack in RC beams without stirrups develops through the theoretical compression strut reducing the shear strength following the shear failure. The main parameter affecting the crack pattern and the shear strength of the beams is the shear slenderness. However, the test results presented in the paper indicated the new arching effect due to the bond losing between the GFRP flexural reinforcement and concrete. This failure mode revealed unexpected critical crack pattern and failure mode. The research of concrete beams flexurally reinforced with GFRP bars without stirrups indicated two failure modes: typical shear-compression and a new one leading by the bond losing between the ordinary reinforcement and concrete.

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Autorzy i Afiliacje

M. Kaszubska
R. Kotynia

Abstrakt

This paper describes a fiber-based model proposed for computing the nonlinear longitudinal shear distribution in composite steel-concrete beams. The presented method incorporates the accurate stress-strain relationship with strain softening for concrete and bi-linear constitutive relation for structural steel, both in agreement with Eurocodes, however any one-dimensional constitutive relation can be used. The numerical solution for a simply supported beams loaded with the uniform load, concentrated force and both was presented. The results indicate that the highest value of the shear flow for a beam under an uniform load is at the ends and in the one third of the span length and for the point load, the maximum shear is in the proximity of the concentrated force.

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Autorzy i Afiliacje

B. Grzeszykowski
E. Szmigiera

Abstrakt

The aim of the study was to determine the shear strength of mineral and anthropogenic soil of similar grain size as a function of the applied shear rate and water saturation. Stability calculations using the finite element method of the road embankment model were also carried out to demonstrate the variation in factor of safety values depending on the adopted values of the angle of internal friction and cohesion. The tests were carried out in a direct shear apparatus in a 100 x 100 mm box with a sample height of 20.5 mm. The samples were formed directly in the apparatus box at optimum moisture content until a compaction index of IS = 1.00 was obtained. Tests were carried out under conditions without and with water saturation at shear rates of 0.01, 0.05, 0.1, 0.5 and 1.0 mm•min–1 until 18% horizontal displacement was achieved. The results showed that the effect of shear rate on the strength parameters was not unequivocal and was much smaller than the changes caused by saturation of samples. An increase in shear rate resulted in small changes in the angle of internal friction with a tendency towards a decrease. In contrast, cohesion varied over a much larger range with increasing shear rate, with an apparent initial decrease and subsequent increase. The saturation of the samples resulted in a decrease in the angle of internal friction of the cohesive soil and an increase for the ash-slag mixture. The cohesion of both soils decreased. The results obtained from the road embankment model stability calculations confirmed that soil saturation had a greater influence on the factor of safety values obtained than the shear rate.
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Autorzy i Afiliacje

Andrzej Gruchot
1
Tymoteusz Zydron
2

  1. University of Agriculture in Kraków, Faculty of Environmental Engineering and Land Surveying,Department of Hydraulic Engineering and Geotechnics, al. Mickiewicza 24/28, 30-059 Kraków, Poland
  2. University of Agriculture in Kraków, Faculty of Environmental Engineering and LandSurveying, Department of Hydraulic Engineering and Geotechnics, al. Mickiewicza 24/28, 30-059 Kraków, Poland

Abstrakt

This study is devoted to the instantaneous acoustic heating of a shear-thinning fluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. That feature distinguishes it from a viscous Newtonian fluid. The special linear combination of conservation equations in the differential form makes it possible to derive dynamic equations governing both the sound and non-wave entropy mode induced in the field of sound. These equations are valid in a weakly nonlinear flow of a shear-thinning fluid over an unbounded volume. They both are instantaneous, and do not require a periodic sound. An example of a sound waveform with a piecewise constant shear rate is considered as a source of acoustic heating.

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Autorzy i Afiliacje

Anna Perelomova

Abstrakt

Longitudinal and shear ultrasonic wave velocities were measured versus temperature in the viscosity standards of Paragon S8000S, N30000S and Cannon N2700000. The measurements were performed by the through-transmission method at the frequency of 2 MHz. Ultrasonic pulses were sent via polymethyl methacrylate (PMMA) waveguides between the tips of which a small amount of the particular standard liquid was placed. The velocities of longitudinal and shear waves were determined to depend on the viscosity of the liquid and increase with the viscosity.
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Autorzy i Afiliacje

Rymantas Kazys
Algirdas Voleisis
Reimondas Sliteris

Abstrakt

This paper presents the results of an extensive investigation of asphalt concrete beams with geosynthetics interlayer. The subject of the research is an evaluation of infl uence of geosynthetics interlayer applied to bituminous samples on their fatigue life. The results of the tests evidences that when geosynthetics are used, the fatigue life depends mainly on the type of bituminous mixture, the type of geosynthetics, and the type and the amount of bitumen used for saturation and sticking. The amount of bitumen used to saturate and fix the geosynthetic signifi cantly changes the samples fatigue properties. Essential positive correlation between fatigue and parameters of interlayer bonding (shear strength, shear stiffness) occurs in both testing temperatures.

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Autorzy i Afiliacje

P. Zieliński

Abstrakt

Two types of submerged membrane bioreactors (MBR): hollow fiber (HF) and hollow sheet (HS), have been studied and compared in terms of energy consumption and average shear stress over the membrane wall. The analysis of energy consumption was made using the correlation to determine the blower power and the blower power demand per unit of permeate volume. Results showed that for the system geometries considered, in terms the of the blower power, the HF MBR requires less power compared to HS MBR. However, in terms of blower power per unit of permeate volume, the HS MBR requires less energy. The analysis of shear stress over the membrane surface was made using computational fluid dynamics (CFD) modelling. Experimental measurements for the HF MBR were compared with the CFD model and an error less that 8% was obtained. For the HS MBR, experimental measurements of velocity profiles were made and an error of 11% was found. This work uses an empirical relationship to determine the shear stress based on the ratio of aeration blower power to tank volume. This relationship is used in bubble column reactors and it is extrapolate to determine shear stress on MBR systems. This relationship proved to be overestimated by 28% compared to experimental measurements and CFD results. Therefore, a corrective factor is included in the relationship in order to account for the membrane placed inside the bioreactor.
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Autorzy i Afiliacje

Nicolas Ratkovich
Thomas R. Bentzen
Michael R. Rasmussen

Abstrakt

Ag and Cu powders were mechanically alloyed using high-energy planetary milling to evaluate the sinter-bonding characteristics of a die-attach paste containing particles of these two representative conductive metals mixed at atomic scale. This resulted in the formation of completely alloyed Ag-40Cu particles of 9.5 µm average size after 3 h. The alloyed particles exhibited antioxidation properties during heating to 225°C in air; the combination of high pressure and long bonding time at 225°C enhanced the shear strength of the chip bonded using the particles. Consequently, the chips sinter-bonded at 225°C and 10 MPa for 10 min exhibited a sufficient strength of 15.3 MPa. However, an increase in bonding temperature to 250°C was detrimental to the strength, due to excessive oxidation of the alloyed particles. The mechanically alloyed phase in the particle began to decompose into nanoscale Ag and Cu phases above a bonding temperature of 225°C during heating.

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Autorzy i Afiliacje

Woo Lim Choi
Jong-Hyun Lee

Abstrakt

Inclinedweb box girders are widely used in urban areas because of their attractive appearance. However, there are few studies on the vehicle shear force distribution of this type of bridge. In this study, we established 62 three-dimensional finite element models in which the shear force of each web of the box girder can be extracted; furthermore, we investigated the shear force distribution law in webs of the box girder under live loads, including single-chamber and multichamber inclined web box girders. The main parameters studied include the number of vehicle lanes and chambers, slope of the inclined webs, and support conditions. The results reveal that an uneven distribution of web shear force exists in both the single-chamber box girder and multichamber girder under live loads, and the maximum value of the vehicle shear force distribution factor is greater than the average shear value shared by all webs. Therefore, the uneven distribution of shear force in the webs of the box girder cannot be ignored under eccentric vehicle loads. These values greatly exceed the safety factor of 1.15 that is used in conventional calculations.
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Autorzy i Afiliacje

Yujun Cui
1
ORCID: ORCID
Longqing Wu
1
ORCID: ORCID
Weiqi Wang
1
ORCID: ORCID
Wei Cao
1
ORCID: ORCID
Xingwei Xue
1
ORCID: ORCID

  1. School of Traffic Engineering, Shenyang Jianzhu University, Shenyang, Liaoning, China

Abstrakt

Recently, textile reinforced concrete (TRC) has been intensively studied for strengthening reinforced concrete (RC) and masonry structures. This study is to experimentally explore the effectiveness of application of carbon TRC to strengthen RC beam in flexure and shear. Concerning the cracks formation, failure modes, ultimate strength and overall stiffness, the performance of the strengthened beams compared to the control beams were evaluated from two groups of tests. The test results confirm that the TRC layers significantly enhance both shear and flexural capacity of RC beams in cracking, yielding and ultimate loads. All of the tested specimens were also modelled using ABAQUS/CAE software, in order to validate the experimental results. The numerical results show that the simulation models have good adaptability and high accuracy.

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Autorzy i Afiliacje

Cuong Huy Nguyen
Quang Dang Ngo

Abstrakt

The subject of this article is the analysis of the relationship between G 0/ M DMT and K D, where G 0 is the small strain shear modulus, while M DMT and K D are respectively the constrained modulus and the horizontal stress index determined from DMT tests. This relationship allows to determine a profile with depth of G 0 from standard DMT test results, useful when data from nonseismic DMT investigations are available. The analysis was based on a large amount of data for a wide range of soils of different origins in Poland. The dataset included OC and NC loams, silts, medium sands, silty sands and fine sands. The overconsolidation ratio (OCR) was estimated using data from CPTU and DMT tests. The obtained empirical G 0/ M DMT vs. K D relationships were compared with the correlations established by Marchetti et al. [1] for different soil types. To account for the significant influence of overconsolidation, an original empirical relationship between G 0/�� p and K D, where �� p is the preconsolidation stress, was defined based on data from all investigated fine-grained soils.
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Autorzy i Afiliacje

Zbigniew Młynarek
1
ORCID: ORCID
Jędrzej Wierzbicki
2
ORCID: ORCID
Paola Monaco
3
ORCID: ORCID
Katarzyna Stefaniak
2
ORCID: ORCID

  1. University of Life Sciences, Poznan, Poland
  2. Institute of Geology, Adam Mickiewicz University, Poznan, Poland
  3. University of L’Aquila, L’Aquila, Italy

Abstrakt

The paper presents numerical and experimental research on glulam delamination in a double lap connection with predominant shear stresses. Laboratory tests and wide literature survey enabled to determine timber and glue joint parameters. Cohesive zone theory, generally used for epoxy matrix and fiber reinforced composites, was adopted to modelling glue layer delamination in glulam elements. Numerical models were validated with laboratory tests.

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Autorzy i Afiliacje

B. Kawecki
J. Podgórski

Abstrakt

Although there are many methods and instruments for measuring viscosity, it is still difficult to determine a reliable value of the dynamic viscosity of complex chemicals such as paraffins and fatty acids. This is due to the complex and heterogeneous structure of these compounds in the case of commercial products. On the other hand, the measuring instrument should be selected very carefully, including its measuring principle and measuring range. This paper presents results of viscosity measurements of three organic PCMs (phase change materials) obtained in four different research institutions. Commercial products: paraffin, myristic acid (97%) and mixture of palmitic acid (55%) and stearic acid (45%) were selected as PCMs. Four different viscometers, namely Fungilab V-Pad, Rheotest LK 2.2, Rheometer Anton Paar MCR 102, and Brookfield DV-II + Pro have been used to determine temperature dependent dynamic viscosity of the tested PCMs. Using a large database of present measurement results, correlations were developed to calculate the dynamic viscosity of fatty acids and paraffins, which predict the experimental data within a band of ±20%.
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Autorzy i Afiliacje

Janusz Tadeusz Cieśliński
1
Maciej Fabrykiewicz
1
Tomasz Stefan Wiśniewski
2
Michał Kubiś
2
Sławomir Smoleń
3
Albrecht Eicke
3
Krzysztof Dutkowski
4
Małgorzata Głuszek-Czarnecka
5

  1. Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland
  2. Warsaw University of Technology, Nowowiejska 21/25, 00-665 Warsaw, Poland
  3. Hochschule Bremen, JR Mayer-Institut für Energietechnik, Neustadswall 30, 28199 Bremen, Germany
  4. Koszalin University of Technology, Racławicka 15-17, 75-620 Koszalin, Poland
  5. Smart Fluid Inc., Rydygiera 8/20A, 01-793 Warsaw, Poland

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