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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Tests of concrete flanged beams reinforced with CFRP bars.

Ashour, Ashraf, Family, M. 11 1900 (has links)
Yes / Tests results of three flanged and two rectangular cross-section concrete beams reinforced with carbon fibre reinforced polymer (CFRP) bars are reported. In addition, a companion concrete flanged beam reinforced with steel bars is tested for comparison purposes. The amount of CFRP reinforcement used and flange thickness were the main parameters investigated in the test specimens. One CFRP reinforced concrete rectangular beam exhibited concrete crushing failure mode, whereas the other four CFRP reinforced concrete beams failed due to tensile rupture of CFRP bars. The ACI 440 design guide for FRP reinforced concrete members underestimated the moment capacity of beams failed due to CFRP tensile rupture and reasonably predicted deflections of the beams tested. A simplified theoretical analysis for estimating the moment capacity of concrete flanged beams reinforced with FRP bars was developed. The experimental moment capacity of the CFRP reinforced concrete beams tested compared favourably with that predicted by the theoretical analysis developed.
102

Improving bond of fiber-reinforced polymer bars with concrete through incorporating nanomaterials

Wang, X., Ding, S., Qiu, L., Ashour, Ashraf, Wang, Y., Han, B., Ou, J. 07 May 2022 (has links)
Yes / The bond between FRP bars and concrete, the foremost performance for implementation of such reinforcements to corrosion-free concrete structures, is still unsatisfied due to the weak nature of duplex film in the interface. The existing approaches show low efficiency in improving the microstructures and bond between FRP bars and concrete. To address these issues, this paper provided a new approach for improving the bond between FRP bars and concrete by incorporating nanomaterials, as well as explored the modifying mechanisms and established the bond-slip models. For these purposes, the pull-out test, scanning electron microscope observation, as well as energy dispersive spectrometry analysis were performed. The experimental results demonstrated that the presence of nanomaterials increased the ultimate bond strengths between glass/carbon FRP bars and concrete by up to 16.2% and 37.8%, while the corresponding slips decreased by 28.7% and 35.4%, respectively. Such modification effects can be attributed to the optimized intrinsic composition and the reduced pore content of hydration products in the interface, especially in the duplex film, through the nanomaterial enrichment and nano-core effects. The bond-slip relationship between FRP bars and concrete with nanomaterials can be accurately predicted by the mBPE model. / The authors would like to thank the funding offered by the National Science Foundation of China (51978127 and 51908103), and the Fundamental Research Funds for the Central Universities (DUT21RC(3) 039).
103

Behaviour of continuous concrete slabs reinforced with FRP bars : experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs

Mahroug, Mohamed Elarbi Moh January 2013 (has links)
An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS-M03-07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440-1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment-curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
104

Fit men New England tavern keepers, 1620-1720 /

Carmichael, Zachary Andrew. January 2009 (has links)
Thesis (M.A.)--Miami University, Dept. of History, 2009. / Title from first page of PDF document. Includes bibliographical references (p. 50-54).
105

Pubs, punters, and pints anthropological reflections on pub life in Ireland /

Cucchiara, J. January 2009 (has links)
Thesis (M.A.)--University of Central Florida, 2009. / Adviser: Ty Matejowsky. Includes bibliographical references (p. 34-39).
106

Systém ICT rolí a jejich hodnocení / ICT roles system and their appraisal

Ostatek, Jan January 2008 (has links)
This diploma thesis addresses the ICT employee evaluation methods in conjunction with their ICT roles. The objective of this work is to produce the lead-in for ICT managers, Human Resources staff etc. for creation of employee evaluation systems or motivation programs in the workplaces with high rate of ICT professions. The work strives to combine psychological and informatics insight to offer corresponding evaluation instruments for each ICT role.
107

Behaviour of continuous concrete slabs reinforced with FRP bars. Experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs.

Mahroug, Mohamed E.M. January 2013 (has links)
An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS¿M03¿07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440¿1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment¿curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
108

Flexural behavior of ECC–concrete hybrid composite beams reinforced with FRP and steel bars

Ge, W-J., Ashour, Ashraf, Yu, J., Gao, P., Cao, D-F., Cai, C., Ji, X. 09 November 2018 (has links)
Yes / This paper aims to investigate the flexural behavior of engineered cementitious composite (ECC)-concrete hybrid composite beams reinforced with fiber reinforced polymer (FRP) bars and steel bars. Thirty two hybrid reinforced composite beams having various ECC height replacement ratio and combinations of FRP and steel reinforcements were experimentally tested to failure in flexure. Test results showed that cracking, yield and ultimate moments as well as the stiffness of hybrid and ECC beams are improved compared with traditional concrete beams having the same reinforcement, owing to the excellent tensile properties of ECC materials. The average crack spacing and width decrease with the increase of ECC height replacement ratio. The ductility of hybrid reinforced composite beams is higher than that of traditional reinforced concrete beams while their practical reinforcement ratios are similar. Reinforced ECC beams show considerable energy dissipation capacity owing to ECC’s excellent deformation ability. Considering the constitutive models of materials, compatibility and equilibrium conditions, formulas for the prediction of cracking, yield and ultimate moments as well as deflections of hybrid reinforced ECC-concrete composite beams are developed. The proposed formulas are in good agreement with the experimental results. A comprehensive parametric analysis is, then, conducted to illustrate the effect of reinforcement, ECC and concrete properties on the moment capacity, curvature, ductility and energy dissipation of composite beams. / National Natural Science Foundation of China (51678514, 51308490), the Natural Science Foundation of Jiangsu Province, China (BK20130450), Six Talent Peaks Project of Jiangsu Province (JZ-038, 2016), Graduate Practice Innovation Project of Jiangsu Province (SJCX17-0625), the Jiangsu Government Scholarship for Overseas Studies and Top-level Talents Support Project of Yangzhou University
109

Sociabilités de comptoir : une ethnographie des débits de boissons / Drinking places : a sociological perspecitve of norms and behaviours in bars

Niedzielski, Pierre-Emmanuel 24 September 2018 (has links)
Les débits de boissons que l’on préfère les appeler cafés, bars, troquets ou autres font partie de nos sociétés depuis plusieurs siècles. A ce titre ils nous paraissent parfois familier, les connaissons nous vraiment ? A travers le discours d’une quarantaine de personnes qui ont partagé leurs expériences et le sens qu’ils donnent à leurs pratiques, cette thèse propose une exploration des usages en cours des débits de boissons, des raisons qui nous y conduisent jusqu’aux ritualités qui accompagnent les façons d’y consommer. Scindés autour de plusieurs axes qui déterminent les normes comportementales, les débits de boissons ne sont pas vécus ni envisagés de la même façon selon qu’il s’agisse du jour ou de la nuit, que l’on s’y rende seul ou accompagné. Ces axes influent sur les façons de boire, le choix du lieu et les rencontres qui s’y produisent ou non. Cette orchestration variée et pourtant harmonieuse est détaillée au cours de cette recherche offre une réponse originale quant à la place qu’ils occupent dans nos sociétés. / The drinking establishments that we sometimes call cafes or bars have been part of our societies for several centuries. As such they seem to us sometimes familiar but do we really know them ?Through the speech of some forty people who have shared their experiences and the meaning they give to their practices, this thesis proposes an exploration of the current uses of drinking establishments, the reasons that lead us there, to the rituals which accompany the ways of consuming alcohol. Split between several axes that determine behavioral norms, drinking establishments are not experienced or considered in the same way depending on whether it is day or night, whether one goes there alone or accompanied. These axes influence the ways of drinking, the choice of place and the encounters that occur there or not. This varied and yet harmonious orchestration is detailed during this research and offers an original answer as to the place they occupy in our societies.
110

Environmental tobacco smoke exposure, respiratory and cardiovascular health in restaurant and bar workers in Mexico.

Barrientos Gutierrez, Tonatiuh. Amick, Benjamin C. Delclos, George L. Gimeno Ruiz de Porras, David Harrist, Ronald B. Hernández-Avila, Mauricio, Kelder, Steven H. Unknown Date (has links)
Source: Dissertation Abstracts International, Volume: 70-07, Section: B, page: 4054. Adviser: Benjamin C. Amick. Includes bibliographical references.

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