197,239 research outputs found
High-power CMOS current driver with accurate transconductance for electrical impedance tomography
No full textCurrent drivers are fundamental circuits in bioimpedance measurements including electrical impedance tomography (EIT). In the case of EIT, the current driver is required to have a large output impedance to guarantee high current accuracy over a wide range of load impedance values. This paper presents an integrated current driver which meets these requirements and is capable of delivering large sinusoidal currents to the load. The current driver employs a differential architecture and negative feedback, the latter allowing the output current to be accurately set by the ratio of the input voltage to a resistor value. The circuit was fabricated in a 0.6- μm high-voltage CMOS process technology and its core occupies a silicon area of 0.64 mm (2) . It operates from a ± 9 V power supply and can deliver output currents up to 5 mA p-p. The accuracy of the maximum output current is within 0.41% up to 500 kHz, reducing to 0.47% at 1 MHz with a total harmonic distortion of 0.69%. The output impedance is 665 k Ω at 100 kHz and 372 k Ω at 500 kHz
josuemtzmo/xarrayMannKendall: Mann Kendall significance test implemented in xarray.
No full textThis release contains an implementation of the Mann-Kendall significance test implemented in xarray. This currently supports 1D, 2D, and 3D datasets.
Additionally, this code was used to analyze the datasets of the manuscript:
> Martínez-Moreno, J., Hogg, A. McC., England, M. H., Constantinou, N. C., Kiss, A. E., and Morrison, A. K. Global changes in oceanic mesoscale currents over the satellite altimetry record. (submitted on Oct. 2020; preprint at doi:10.21203/rs.3.rs-88932/v1
josuemtzmo/EKE_SST_trends: EKE_SST_trends: Jupyter notebooks (Python) used to compute trends of Eddy kinetic energy and sea surface temperature
No full textThis repository contains the most recent code, figures and notebooks used to reproduce the manuscript:
Martínez-Moreno, J., Hogg, A. McC., England, M. H., Constantinou, N. C., Kiss, A. E., and Morrison, A. K. Global changes in oceanic mesoscale currents over the satellite altimetry record. (accepted on Feb. 2021; preprint at doi:10.21203/rs.3.rs-88932/v1)
The version of the toolboxes here correspond to the Github site:
https://github.com/josuemtzmo/EKE_SST_trend
O(a^2) corrections to the one-loop propagator and bilinears of clover fermions with Symanzik improved gluons
No full textWe calculate corrections to the fermion propagator and to the Green's functions of all fermion bilinear operators of the form (Psi) over bar Gamma Psi, to one-loop in perturbation theory. We employ the Wilson/clover action for fermions and the Symanzik improved action for gluons. The novel aspect of our calculations is that they are carried out to second order in the lattice spacing, O (a(2)). Consequently, they have addressed a number of new issues, most notably the appearance of loop integrands with strong IR divergences (convergent only beyond 6 dimensions). Such integrands are not present in O (a(1)) improvement calculations; there, IR divergent terms are seen to have the same structure as in the O (a(0)) case, by virtue of parity under integration, and they can thus be handled by well-known techniques. We explain how to correctly extract the full O (a(2)) dependence; in fact, our method is generalizable to any order in a. The O (a(2)) corrections to the quark propagator and Green's functions computed in this paper are useful to improve the nonperturbative RI-MOM determination of renormalization constants for quark bilinear operators. Our results depend on a large number of parameters: coupling constant, number of colors, lattice spacing, external momentum, clover parameter, Symanzik coefficients, gauge parameter. To make these results most easily accessible to the reader, we have included them in the distribution package of this paper, as an ASCII file named: Oa2results. m; the file is best perused as Mathematica input
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Mechanisms of pelvic floor muscle function and the effect on the urethra during a cough
No full textBackground: Current measurement tools have difficulty identifying the automaticphysiologic processes maintaining continence, and many questions still remainabout pelvic floor muscle (PFM) function during automatic events.Objective: To perform a feasibility study to characterise the displacement, velocity,and acceleration of the PFM and the urethra during a cough.Design, setting, and participants: A volunteer convenience sample of 23 continentwomen and 9 women with stress urinary incontinence (SUI) from the generalcommunity of San Francisco Bay Area was studied.Measurements: Methods included perineal ultrasound imaging, motion trackingof the urogenital structures, and digital vaginal examination. Statistical analysisused one-tailed unpaired student t tests, and Welch’s correction was applied whenvariances were unequal.Results and limitations: The cough reflex activated the PFM of continent women tocompress the urogenital structures towards the pubic symphysis, which wasabsent in women with SUI. The maximum accelerations that acted on the PFMduring a cough were generally more similar than the velocities and displacements.The urethras of women with SUI were exposed to uncontrolled transverse accelerationand were displaced more than twice as far ( p = 0.0002), with almost twicethe velocity ( p = 0.0015) of the urethras of continent women. Caution regardingthe generalisability of this study is warranted due to the small number of women inthe SUI group and the significant difference in parity between groups.Conclusions: During a cough, normal PFM function produces timely compressionof the pelvic floor and additional external support to the urethra, reducing displacement,velocity, and acceleration. In women with SUI, who have weakerurethral attachments, this shortening contraction does not occur; consequently,the urethras of women with SUI move further and faster for a longer duratio
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Perturbative renormalization of staggered fermion operators with stout improvement: Application to the magnetic susceptibility of QCD
No full textBali G, Bruckmann F, Constantinou M, et al. Perturbative renormalization of staggered fermion operators with stout improvement: Application to the magnetic susceptibility of QCD. In: Proceedings of 31st International Symposium on Lattice Field Theory LATTICE 2013 — PoS(LATTICE 2013). Trieste, Italy: Sissa Medialab; 2014: 458
Computational Investigation of Microreactor Configurations for Hydrogen Production from Formic Acid Decomposition Using a Pd/C Catalyst
No full textThe need to replace fossil fuels with sustainable alternatives has been a critical issue in recent years. Hydrogen fuel is a promising alternative to fossil fuels because of its wide availability and high energy density. For the very first time, novel microreactor configurations for the formic acid decomposition have been studied using computational modeling methodologies. The decomposition of formic acid using a commercial 5 wt % Pd/C catalyst, under mild conditions, has been assessed in packed bed, coated wall, and membrane microreactors. Computational fluid dynamics (CFD) was utilized to develop the comprehensive heterogeneous microreactor models. The CFD modeling study begins with the development of a packed bed microreactor to validate the experimental work, subsequently followed by the theoretical development of novel microreactor configurations to perform further studies. Previous work using CFD modeling had predicted that the deactivation of the Pd/C catalyst was due to the production of the poisoning species CO during the reaction. The novel membrane microreactor facilitates the continuous removal of CO during the reaction, therefore prolonging the lifetime of the catalyst and enhancing the formic acid conversion by approximately 40% when compared to the other microreactor configurations. For all microreactors studied, the formic acid conversion increases as the temperature increases, and the liquid flow rate decreases. Further studies revealed that all microreactor configurations had negligible internal and external pore diffusion resistances. The detailed models developed in this work have provided an interesting insight into the intensification of the formic acid decomposition reaction over a Pd/C catalyst
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