2,787 research outputs found
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
Multi-instrumental Analysis of the Extreme Meteorological Event Occurred in Matera (Italy) on November 2019
No full textMost of the municipalities of the Italian territory are located in areas of high hydrogeological risk, i.e. exposed to flooding and landslides. Consequently, part of the existing cultural heritage on the national territory is located in areas subject to flood risk, which compromises the accessibility, preservation and integrity of cultural heritage. As an example, we consider a single flood event that occurred in southern Italy on November 11th and 12th, 2019, which mainly affected the city of Matera and its surroundings. This episode appears to be significant for the violence of the phenomenon that led to considerable quantities of water flowing inside the city, a UNESCO World Heritage Site, causing damage to buildings, including historical ones. The event has been analysed using both meteorology and geomatic technologies, to have an overview on spatial and temporal evolution of the phenomenon. Global Navigation Satellite System Zenith Total Delay (GNSS-ZTD) data obtained by receivers located around the city of Matera, were compared with measurements from ground-based devices (i.e. weather stations), Numerical Weather Prediction (NWP) models, and ERA5 reanalysis. To assess the extent of the flood and show the flooded areas, the images provided by the Sentinel-1 Synthetic Aperture Radar (SAR) were used, isolating and analyzing the images captured before and after the event. Finally, through a digital terrain model, developed using Agisoft Metashape software from satellite images, the morphology of Matera was recreated to evidence the areas of accumulation of water. Once all the information was obtained, the data correlated showed an overall view of the event
Preliminary Results of the AEROMET Project on the Assimilation of the Rain-Rate from Satellite Observations
No full textThe regions close to the sea are often hit by meteorological systems that generate over the sea and then are advected towards the land. These systems impact the activities over the sea and is it important to predict their occurrence for the safety of the people as well as for the best prediction of ship-routes. The lower number of meteorological observations over the sea compared to the land and the absence of the orographic triggering mechanism, makes prediction of these storms difficult. Satellite observations are very important in this framework because they provide data over both land and sea that can help the prediction of convective storms.The AEROMET project (AEROspatial data assimilation for METeorological weather prediction) aims to assimilate the rain-rate estimated from satellite observations into the Numerical Weather Prediction (NWP) Weather Research and Forecasting (WRF) model to improve the prediction of convective meteorological systems, especially those originating over the sea. The method to assimilate the rain-rate is straightforward: given the best estimate of the rain-rate, it is assimilated in the model through 3D-Var with a simple cloud model. Two examples, occurred on 10 December 2021 and on 15 February 2022, show the feasibility of the method, nevertheless many cases must be studied to quantify the impact of the assimilation of satellite observed rain-rate on the precipitation forecast
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
A CMOS Dual-RC frequency reference with ±250ppm inaccuracy from -45°C to 85°C
No full textTo comply with wired communication standards such as USB, SATA and PCI/PCI-E, systems-on-chip require frequency references with better than 300ppm accuracy. LC-based references achieve 100ppm accuracy [1], but suffer from high power consumption (∼20mW). Thermal diffusivity (TD) references require less power (∼2mW), at the expense of less accuracy (1000ppm) [2]. RC-based references offer the lowest power consumption, but their accuracy is typically limited to ∼0.1% [3]. In RC relaxation oscillators, comparator offset and delay are the major sources of inaccuracy [4,5]. References based on frequency-locked loops (FLLs) circumvent these by locking an oscillator's frequency to the time-constant of an RC filter, but their accuracy is then limited by the nonlinear temperature dependency of on-chip resistors [3,6].Session 3.3 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 Instrumentation(OLD)Applied Quantum ArchitecturesMicroelectronic
Experimental and theoretical investigation of crack width calculation methods for RC ties
No full textThis paper theoretically and experimentally investigates the semi-empirical formulas recommended by Eurocode 2 (EC2), fib Model Code 2010 (MC2010), and Eurocode 2 with the German National Annex (DIN) for calculating crack widths in reinforced concrete. It is shown that the formulas can be derived from the principles for the idealized behavior of RC ties. However, instead of explicitly solving the resulting differential equations, the use of simplifications leads to inconsistent formulas. An experimental study was carried out involving the testing of eight RC ties to discover the modeling uncertainty of the formulas. It was found that EC2 substantially overestimated the crack widths for the RC ties. MC2010 and DIN seemed to predict the crack widths better, but gave rather a large number of nonconservative crack width predictions. These experimental results, combined with the theoretical study, suggest that a more consistent calculation model should be formulated by explicitly solving the resulting differential equation.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.Applied Mechanic
RC SMOOTHING OF SPECTRA
No full textAuthor Institution: Department of Physics, Michigan State University East LansingBy convoluting an exponential function with calculated spectra consisting of single and multiple sets of lines of various widths and line shapes, we have determined the effects that time constant (RC) has on recorded spectra. For equivalent experiments, in which the scanning rates d/dt are equal, we have concluded that the optimum value of RC is essentially independent of whether the spectrum is to be digitized or not, and independent of the sampling rate if digitization is used. A trade-off among the desirable and undesirable effects of RC leads us to recommend a value of RC about one-tenth of the full width at half height of the sharpest individual lines in the observed spectrum. This research was supported by a grant from the National Science Foundation
Nonlinear analysis to investigate effect of connection type on behavior of steel plate shear wall in RC frame
No full textIn the reinforced concrete (RC) structures with steel plate shear walls (SPSWs) as a lateral resisting system, to obtain maximum capacity of SPSW, implementing proper connections play an important role to transfer force from wall to the frame. In this paper, four connection types are proposed and numerically investigated to transfer the tension field forces between SPSW and RC frame (RCF). Three types of connections are applicable for rehabilitating of existing RC structures and one type can be used for new construction. The behavior of connections has been evaluated using non-linear finite element analysis (NLFEA). Results of the specimens with different types of connections demonstrated that the use of SPSW in RCF with appropriate connections could provide excellent ductility as well as high load carrying capacity and initial stiffness by distributing the yielding zone in SPSW along the wall height
AgnostiqHQ/covalent: v0.234.1-rc.0
No full text<h2>[0.234.1-rc.0] - 2024-05-10</h2>
<h3>Authors</h3>
<ul>
<li>Andrew S. Rosen <a href="mailto:[email protected]">[email protected]</a></li>
<li>Sankalp Sanand <a href="mailto:[email protected]">[email protected]</a></li>
<li>Co-authored-by: Alejandro Esquivel <a href="mailto:[email protected]">[email protected]</a></li>
<li>Casey Jao <a href="mailto:[email protected]">[email protected]</a></li>
<li>Co-authored-by: Santosh kumar <a href="mailto:[email protected]">[email protected]</a></li>
</ul>
<h3>Fixed</h3>
<ul>
<li>Sublattice electron function strings are now parsed correctly</li>
<li>The keys of dictionary inputs to electrons no longer need be strings.</li>
<li>Fixed inaccuracies in task packing exposed by no longer uploading null attributes upon dispatch.</li>
</ul>
<h3>Operations</h3>
<ul>
<li>Fixed nightly workflow's calling of other workflows.</li>
<li>Fixed input values for other workflows in <code>nightly-tests</code> workflow.</li>
</ul>
<h3>Operations</h3>
<ul>
<li>Removing author email from changelog action</li>
<li>Fixed nightly worfkflow's calling of other workflows.</li>
</ul>
A CMOS Dual- RC Frequency Reference With ±200-ppm Inaccuracy From -45 °C to 85 °C
No full textThis paper presents a 7-MHz CMOS RC frequency reference. It consists of a frequency-locked loop in which the output frequency of a digitally controlled oscillator (DCO) is locked to the combined phase shifts of two independent RC (Wien bridge) filters, each employing resistors with complementary temperature coefficients. The filters are driven by the DCO's output frequency and the resulting phase shifts are digitized by high-resolution phase-to-digital converters. Their outputs are then combined in the digital domain to realize a temperature-independent frequency error signal. This digitally assisted temperature compensation scheme achieves an inaccuracy of ±200 ppm from -45 °C to 85 °C after a two-point trim. The frequency reference draws 430 μA from a 1.8-V supply, while achieving a supply sensitivity of 0.18%/V and a 330-ppb Allan deviation floor in 3 s of measurement time.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 InstrumentationMicroelectronics(OLD)Applied Quantum Architecture
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