An example of active circulation control of the unsteady separated flow past a semi-infinite plate

Active circulation control of the two-dimensional unsteady separated flow past a semiinfinite plate with transverse motion is considered. The rolling-up of the separated shear layer is modelled by a point vortex whose time-dependent circulation is predicted by an unsteady Kutta condition. A suitable vortex shedding mechanism introduced. A control strategy able to maintain constant circulation when a vortex is present is derived. An exact solution for the nonlinear controller is then obtained. Dynamical systems analysis is used to explore the performance of the controlled system. The control strategy is applied to a class of flows and the results are discussed. A procedure to determine the position and the circulation of the vortex, knowing the velocity signature on the plate, is derived. Finally, a physical explanation of the control mechanism is presented

muCap: Connecting FaceReader™ to z-Tree

μCap (muCap) is a software package (citeware) for economic experiments enabling experimenters to analyze emotional states of subjects using z-Tree and FaceReader™. μCap is able to create videos of subjects on client computers based on stimuli shown on screen and restrict recording material to relevant time frames. Another feature of μCap is the creation of time stamps in csv format at prespecified screens (or at prespecified points in time) during the experiment, measured on the client computer. The software makes it possible to import these markers into FaceReader™ easily. Until recently, connecting z-Tree and FaceReader™ was only possible using workarounds or by undertaking many successive actions manually. μCap is the first program that significantly simplifies this process with the additional benefit of extremely high precision. This paper describes the usage, underlying principles as well as advantages and limitations of μCap. Furthermore, we give a brief outlook of how μCap can be beneficial in other contexts

Plenary Panel Discussion: Challenges and opportunities for the future of control

This panel reflects the scope and diversity of the unprecedented challenges and opportunities for the systems and controls community that has been created by several research themes from the basic sciences to advanced technologies. Connecting physical processes at multiple time and space scales in quantum, statistical, fluid, and solid mechanics, remains not only a central scientific challenge but also one with increasing technological implications. This is particular so in highly organized and nonequilibrium systems as in biology and nanotechnology, where interconnection, feedback, and dynamics are playing an increasingly central role

My Dream of the U. S. A.: Quartette Chorus

https://digitalcommons.library.umaine.edu/mmb-vp/2912/thumbnail.jp

My Dream of the USA

VERSE 1A soldier in camp lay dreaming,Dreaming of his native land,He saw her noble statesmanAnd blood-stained heroes, grand;He saw her soldiers and sailorsAnd the boys in Blue and Gray;At dawn unto his comrades,These words I heard him say: CHORUS“I saw Washington cross the Delaware,I saw Stark ‘mid Mountains Green;I saw Warren fight at Bunker Hill,Andrew Jackson at New Orleans;I saw Davy Crockett at the Alamo,Taylor fight at Monterey,And all fought for our liberty,In my dreams of the U. S. A. VERSE 2At Plymouth he saw the landingOf the gallant Pilgrim band,He heard a bell ring libertyAnd freedom thro’ the land;O’er battle fields he wandered,Where her heroes fought and fell;Then turning to his comrades,These words I heard him tell. CHORU

Experimental estimates of the photon background in a potential light-by-light scattering study

High power short pulse lasers provide a promising route to study the strong field effects of the quantum vacuum, for example by direct photon–photon scattering in the all-optical regime. Theoretical predictions based on realistic laser parameters achievable today or in the near future predict scattering of a few photons with colliding Petawatt laser pulses, requiring single photon sensitive detection schemes and very good spatio-temporal filtering and background suppression. In this article, we present experimental investigations of this photon background by employing only a single high power laser pulse tightly focused in residual gas of a vacuum chamber. The focal region was imaged onto a single-photon sensitive, time gated camera. As no detectable quantum vacuum signature was expected in our case, the setup allowed for characterization and first mitigation of background contributions. For the setup employed, scattering off surfaces of imperfect optics dominated below residual gas pressures of 1 × 10−4 mbar. Extrapolation of the findings to intensities relevant for photon–photon scattering studies is discussed

Learnings From a National Cyberattack Digital Disaster During the SARS-CoV-2 Pandemic in a Pediatric Emergency Medicine Department

Objective: The primary objective was to analyze the impact of the national cyberattack in May 2021 on patient flow and data quality in the Paediatric Emergency Department (ED), amid the SARS-CoV-2 (COVID-19) pandemic. Methods: A single site retrospective time series analysis was conducted of three 6-week periods: before, during, and after the cyberattack outage. Initial emergent workflows are described. Analysis includes diagnoses, demographic context, key performance indicators, and the gradual return of information technology capability on ED performance. Data quality was compared using 10 data quality dimensions. Results: Patient visits totaled 13 390. During the system outage, patient experience times decreased significantly, from a median of 188 minutes (pre-cyberattack) down to 166 minutes, most notable for the period from registration to triage, and from clinician review to discharge (excluding admitted patients). Following system restoration, most timings increased. Data quality was significantly impacted, with data imperfections noted in 19.7% of data recorded during the system outage compared to 4.7% before and 5.1% after. Conclusions: There was a reduction in patient experience time, but data quality suffered greatly. A hospital’s major emergency plan should include provisions for digital disasters that address essential data requirements and quality as well as maintaining patient flow

Radiation Protection Using Single-Wall Carbon Nanotube Derivatives

This invention is a means of radiation protection, or cellular oxidative stress mitigation, via a sequence of quenching radical species using nano-engineered scaffolds, specifically single-wall carbon nanotubes (SWNTs) and their derivatives. The material can be used as a means of radiation protection by reducing the number of free radicals within, or nearby, organelles, cells, tissue, organs, or living organisms, thereby reducing the risk of damage to DNA and other cellular components (i.e., RNA, mitochondria, membranes, etc.) that can lead to chronic and/or acute pathologies, including but not limited to cancer, cardiovascular disease, immuno-suppression, and disorders of the central nervous system. In addition, this innovation could be used as a prophylactic or antidote for accidental radiation exposure, during high-altitude or space travel where exposure to radiation is anticipated, or to protect from exposure from deliberate terrorist or wartime use of radiation- containing weapons