12,404 research outputs found
Behavior of RC beams patch repaired and strengthened with FRP composites : a numerical study
No full textIncludes bibliographical references.Reinforced concrete (RC) beams get deteriorated and become deficient mainly due to corrosion of steel reinforcements, poor maintenance and design, earthquakes and aging. Patch repair and structural strengthening using fiber reinforced polymers (FRP) have been increasingly adopted all over the world as an economical solution to upgrade the load carrying capacity of such beams. However, the failure modes of such repaired and strengthened RC beams are governed by brittle and sudden premature debonding which involves separation of external reinforcement; i.e. FRP and RC beam. Different researchers have used different approaches including experimental, analytical and numerical to investigate the behavior of patch repaired and FRP strengthened RC beams. It is noteworthy that there are no such numerical studies that investigated the effect of patch repair. In this study, a numerical investigation was carried out using the commercial finite elements analysis software ABAQUS with the aim of investigating the overall behavior of RC beams patch repaired and strengthened with FRP plates including the failure mechanisms
Modelling delay and noise in arbitrarily coupled RC trees.
No full textClosed-form equations for second-order transfer functions of general arbitrarily coupled resistance-capacitance (RC) trees with multiple drivers are reported. The models allow precise delay and noise calculations for systems of coupled interconnects with guaranteed stability and represent the minimum complexity associated with this class of circuits. Their accuracy is extensively compared against other relevant models and is found to be better or comparable to more expensive models. All results are derived from a theoretical approach, and their physical basis is examined. The simplicity, accuracy, and generality of the models make them suitable for use in early signal integrity analyses of complex systems and incremental physical optimization
RC relaxational oscillator with high supply rejection
No full textA low power RC relaxation oscillator with very low voltage and temperature sensitivities is presented. Supply sensitivity is reduced by using a self-regulation loop that biases the oscillator near its zero-voltage coefficient point. Fabricated in a 65nm CMOS process, the prototype 1.5MHz oscillator consumes 6μW from 1V supply and achieves better than ±50ppm/ ̊C and ±1500ppm/V temperature and voltage sensitivities, respectively.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-05-01The student, Tianyu Wang, accepted the attached license on 2018-04-25 at 16:33.The student, Tianyu Wang, submitted this Thesis for approval on 2018-04-25 at 16:37.This Thesis was approved for publication on 2018-04-26 at 08:25.DSpace SAF Submission Ingestion Package generated from Vireo submission #12497 on 2018-08-31 at 17:30:30Made available in DSpace on 2018-09-04T20:47:31Z (GMT). No. of bitstreams: 2
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Previous issue date: 2018-04-26Embargo set by: Seth Robbins for item 107462
Lift date: 2020-09-04T20:47:38Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 107462
Lift date: 2020-09-04T20:50:11Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 107462 on 2020-09-05T09:15:13Z
Measurable parameters for performance of correded and repaired RC beams under load
No full textIncludes abstract.Includes bibliographical references.Structural engineers and asset managers rely on measurable parameters developed by researchers to predict residual load-bearing capacities of corroding in-service RC structures and to assess repair-effectiveness. Laboratory research that was used to develop these measurable parameters varied between researchers and in most cases, did not represent in-service conditions. As a result, they found different relations between measurable and non-measurable parameters which are unsafe and/or engineers find difficult to apply to in-service structures. A holistic research that emulates in-service conditions was therefore developed. Parameters that were looked at were corrosion crack widths and longitudinal strains together with their derivatives
Strain monitoring of RC members strengthened with smart NSM FRP bars
No full textFiber-reinforced polymer (FRP) bars can be used as internal reinforcement for new reinforced concrete (RC) structures and as near-surface mounted (NSM) reinforcement for the strengthening of RC structures. The NSM method is an emerging strengthening technique for RC structures, where FRP bars are embedded into grooves cut in the cover of RC members. In both cases, strain monitoring of the FRP bars is desirable either for the investigation of the structural behavior or for the long-term health monitoring of the structure. This paper presents a study in which fiber-optic sensors were embedded into glass FRP (GFRP) bars to produce smart GFRP bars for NSM applications. The manufacturing process of the smart FRP bars is illustrated and their performance in tensile, bond and beam flexural tests is examined to assess the effectiveness of these smart FRP bars for achieving the dual purpose of structural strengthening and strain monitoring. On the basis of the test results, the advantages and limitations of fiber-optic sensors compared to electrical strain gages in the strain monitoring of NSM FRP bars are discussed. The bond and beam test results also confirm the effectiveness of the NSM method for the strengthening of RC structures.Department of Civil and Environmental Engineerin
Distribution and internal consistency for the subscales of the C-RC-QOL.
No full textDistribution and internal consistency for the subscales of the C-RC-QOL.</p
A Compact 10-MHz RC Frequency Reference With a Versatile Temperature Compensation Scheme
No full textThis article presents the design and implementation of a compact CMOS RC frequency reference. It consists of a frequency-locked loop (FLL) that locks the period of a voltage-controlled oscillator (VCO) to the time an RC network takes to charge to a reference voltage. Conventionally, an RC time constant with a near-zero temperature coefficient (TC) is realized by using a trimmed network of resistors with different TCs. In this work, such a network is used to realize a temperature-dependent reference voltage whose TC cancels that of a single-resistor RC time constant. Compared with the conventional approach, which requires resistors with TCs of opposite polarity, the proposed approach can be implemented with resistors with TCs of similar polarity, and so it can be implemented in most CMOS processes. To compensate for RC spread, a trimmed capacitor is used to adjust the nominal frequency. Two prototype chips were made, one based on p- /n-polysilicon resistors and other based on silicided/p-diffusion resistors. Fabricated in a standard 180-nm CMOS technology, the polysilicon-based prototype has an active area of 0.01 mm2 and an absolute inaccuracy of ±2800 ppm from -45 °C to 125 °C with a fixed TC-trim and a one-point frequency trim. After one week of accelerated aging at 150 °C, however, significant drift (5000 ppm) was observed. The diffusion-based prototype exhibits greater inaccuracy (±14 400 ppm) but much less drift (600 ppm).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
Reliability, responsiveness and results of the PCA of residuals for the C-RC-QOL <sup>a</sup>.
No full textReliability, responsiveness and results of the PCA of residuals for the C-RC-QOL a.</p
Hypotheses for the correlations between the subscales of the C-RC-QOL, SF-36 and OSS.
No full textHypotheses for the correlations between the subscales of the C-RC-QOL, SF-36 and OSS.</p
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