Virtual Frame Technique: Ultrafast Imaging with Any Camera

Many phenomena of interest in nature and industry occur rapidly and are difficult and cost-prohibitive to visualize properly without specialized cameras. Here we describe in detail the Virtual Frame Technique (VFT), a simple, useful, and accessible form of compressed sensing that increases the frame acquisition rate of any camera by several orders of magnitude by leveraging its dynamic range. VFT is a powerful tool for capturing rapid phenomenon where the dynamics facilitate a transition between two states, and are thus binary. The advantages of VFT are demonstrated by examining such dynamics in five physical processes at unprecedented rates and spatial resolution: fracture of an elastic solid, wetting of a solid surface, rapid fingerprint reading, peeling of adhesive tape, and impact of an elastic hemisphere on a hard surface. We show that the performance of the VFT exceeds that of any commercial high speed camera not only in rate of imaging but also in field of view, achieving a 65MHz frame rate at 4MPx resolution. Finally, we discuss the performance of the VFT with several commercially available conventional and high-speed cameras. In principle, modern cell phones can achieve imaging rates of over a million frames per second using the VFT.Comment: 7 Pages, 4 Figures, 1 Supplementary Vide

A Hierarchical Control Strategy With Fault Ride-Through Capability for Variable Frequency Transformer

A variable frequency transformer (VFT) is being considered as a new alternative to the classical back-to-back high voltage direct current (HVDC) link for interconnection of two asynchronous networks. The VFT is a retrospective form of frequency converter using the wound rotor induction machine (WRIM), which converts the constant frequency input into a variable frequency output. The prime objective of VFT is to achieve controlled bidirectional power transfer between the two asynchronous networks. This paper presents a detailed working principle of VFT technology and proposes a new hierarchical control strategy for establishing the VFT connection with two power systems to achieve bidirectional power transfer between them. Also, to restrict the grid fault propagation from one side of the VFT to the other side, a series dynamic braking resistor based fault ride-through (FRT) scheme is proposed. The performance of the VFT during the synchronization process, steady-state, dynamic, and the grid fault conditions is evaluated using the real-time hardware in-loop (HIL) system. The plant is simulated in real time using OPAL-RT real-time simulator while the control algorithm is implemented in digital signal processor to carry out HIL study. All the important results supporting the effectiveness of the proposed control strategy and FRT scheme are discussed

VFT® - Prefabricated composite construction method

Este documento describe el método VFT como una solución eficiente y estética para puentes con vanos de corta y media longitud. Actualmente, el método presentado en este informe es un fuerte competidor de los puentes de hormigón. Esta combinación entre un uso económico del acero y del hormigón proporciona numerosas ventajas y hace que sea cada vez más usado. Este informe presenta la idea de las vigas VFT, el proceso de fabricación y la rápida construcción pueden explicar la popularidad de esta tecnología especialmente en Alemania y Polonia. Para mostrar las diferencias entre un puente mixto y un puente mixto de vigas prefabricadas se propone una estructura de 2 vigas continuas de 50m de longitud (dos vanos: 25,00m + 25,00m) con las siguientes vigas transversales: · 4 vigas mixtas (acero + hormigón “in situ”) · 4 vigas VFT Se presentan dos modelos de construcción en FEM (Método de Elementos Finitos), usando el software ROBOT MILLENNIUM, y elementos de dimensionado. Como resultado del desarrollo de las vigas VFT e investigaciones de conectores continuos se ha creado una nueva técnica VFT llamada Método de Construcción VFT-WIB. Este documento introduce el diseño estático y a fatiga de los conectores continuos VFT-WIB. Para resumir los métodos descritos, se muestran algunos ejemplos ejecutados en Alemania y Poloni

Efficacy of home-based visuomotor feedback training in stroke patients with chronic hemispatial neglect

Hemispatial neglect is a severe cognitive condition frequently observed after a stroke, associated with unawareness of one side of space, disability and poor long-term outcome. Visuomotor feedback training (VFT) is a neglect rehabilitation technique that involves a simple, inexpensive and feasible training of grasping-to-lift rods at the centre. We compared the immediate and long-term effects of VFT vs. a control training when delivered in a home-based setting. Twenty participants were randomly allocated to an intervention (who received VFT) or a control group (n = 10 each). Training was delivered for two sessions by an experimenter and then patients self-administered it for 10 sessions over two weeks. Outcome measures included the Behavioural Inattention Test (BIT), line bisection, Balloons Test, Landmark task, room description task, subjective straight-ahead pointing task and the Stroke Impact Scale. The measures were obtained before, immediately after the training sessions and after four-months post-training. Significantly greater short and long-term improvements were obtained after VFT when compared to control training in line bisection, BIT and spatial bias in cancellation. VFT also produced improvements on activities of daily living. We conclude that VFT is a feasible, effective, home-based rehabilitation method for neglect patients that warrants further investigation with well-designed randomised controlled trials on a large sample of patients

A novel bacterial l-arginine sensor controlling c-di-GMP levels in Pseudomonas aeruginosa

Nutrients such as amino acids play key roles in shaping the metabolism of microorganisms in natural environments and in host–pathogen interactions. Beyond taking part to cellular metabolism and to protein synthesis, amino acids are also signaling molecules able to influence group behavior in microorganisms, such as biofilm formation. This lifestyle switch involves complex metabolic reprogramming controlled by local variation of the second messenger 3′, 5′-cyclic diguanylic acid (c-di-GMP). The intracellular levels of this dinucleotide are finely tuned by the opposite activity of dedicated diguanylate cyclases (GGDEF signature) and phosphodiesterases (EAL and HD-GYP signatures), which are usually allosterically controlled by a plethora of environmental and metabolic clues. Among the genes putatively involved in controlling c-di-GMP levels in P. aeruginosa, we found that the multidomain transmembrane protein PA0575, bearing the tandem signature GGDEF-EAL, is an l-arginine sensor able to hydrolyse c-di-GMP. Here, we investigate the basis of arginine recognition by integrating bioinformatics, molecular biophysics and microbiology. Although the role of nutrients such as l-arginine in controlling the cellular fate in P. aeruginosa (including biofilm, pathogenicity and virulence) is already well established, we identified the first l-arginine sensor able to link environment sensing, c-di-GMP signaling and biofilm formation in this bacterium

Dataset for holiday rentals’ daily rate pricing in a cultural tourism destination

This data article describes a holiday rental dataset from a medium-size cultural city destination. Daily rate and variables related to location, size, amenities, rating, and seasonality are highlighted as the main features. The data was extracted from Booking.com, legal registration of the accommodation (RTA) and Google Maps, among other sources. This dataset contains data from 665 holiday rentals offered as entire flat (rent per room was discarded), with a total of 1623 cases and 28 variables considered. Regarding data extraction, RTA is ordered by registration number, which is taken and, through a Google search with the following structure: "apartment registration no. + Booking + Seville", the holiday rental profile in Booking.com is found. Then, it is verified that both the address of the accommodation and the registration number match in RTA and Booking.com, proceeding with data extraction to a Microsoft Excel's file. Google Maps is used to determine the minutes spent walking from the accommodation to the spot of maximum tourist interest of the city. A price index based on the average price per square meter of real estate per district is also incorporated to the dataset, as well as a visual appeal rating made by the authors of every holiday rental based on its Booking.com photos profile. Only cases with complete data were considered. A statistics summary of all variables of the data collected is presented. This dataset can be used to develop an estimation model of daily prices of stay in holiday rentals through predetermined variables. Econometrics methodologies applied to this dataset can also allow testing which variables included affecting the composition of holiday rentals' daily rates and which not, as well as determining their respective influence on daily rates.info:eu-repo/semantics/publishedVersio

Thermodynamics and kinetics of the Mg65Cu25Y10 bulk metallic glass forming liquid

The thermodynamics and kinetics of the bulk metallic glass forming Mg65Cu25Y10 liquid were investigated using differential scanning calorimetry and three-point beam bending. The experiments lead to the determination of the thermodynamic functions as well as the viscosity of the supercooled liquid. The viscosity shows a temperature dependence, which is consistent with that of a strong glass similar to Zr–Ti–Cu–Ni–Be bulk metallic glasses or sodium silicate glasses. This contrasts with more fragile conventional metallic glass formers or pure metals. The relatively weak temperature dependence of the thermodynamic functions of the supercooled liquid is related to these sluggish kinetics in the supercooled liquid. Entropy, viscosity, and kinetic glass transition are compared in the frameworks of the fragility concept and the Adam–Gibbs theory. Strong liquid behavior retards the formation of crystals kinetically and thermodynamically

Enhancing Vocabulary Acquisition Through Synthetic Learning Experiences: Implementing Virtual Field Trips Into Classrooms

A Synthetic Learning Environment (SLE) the Virtual Field Trip (VFT) was designed to increase vocabulary acquisition and knowledge by utilizing simulation based technologies and leveraging sound educational findings. Vocabulary acquisition is considered a prerequisite to becoming a good reader and therefore a critical predictor of academic and lifelong success for early learners, however, teachers report that students lack the real world knowledge required for vocabulary knowledge. The VFT provides a meaningful context for anchored and situated instruction. Second grade students were assigned to either use the VFT or to listen to stories read aloud by a researcher on a video tape. While results did not indicate significant vocabulary acquisition on a series of 3 vocabulary tests; students who used the VFT did use significantly more words in a post exposure writing sample than students in the story group indicating an increase of words known at a level of depth sufficient to warrant their use in a writing sample. Students who used the VFT also reported increased motivation to use SLEs like the VFT for future learning objectives and that VFTs were fun. Findings related to the self-efficacy of students as measures immediately following each vocabulary test did not reveal a significant increase for VFT users. Students using the VFTs did not report learning more words than those students assigned to the story group. Limitations of the current study and directions for future research are discussed