Physical Setup Research Articles

K\xe4hler uniformization from holographic renormalization group flows of M5-branes

In this paper, we initiate the study of holographic renormalization group flows for the metric of four-manifolds. In particular, we derive a set of equations which govern the evolution of a generic Kähler four-manifold along the renormalization group flow in seven-dimensional gauged supergravity. The physical eleven-dimensional M-theory setup is given by a stack of M5-branes wrapping a calibrated Kähler four-cycle inside a Calabi-Yau threefold. By topologically twisting the theory in the ultraviolet, we may choose an arbitrary Kähler metric on the four-cycle as an asymptotic boundary condition. We find that at the infrared fixed point, we reach a Kähler-Einstein metric, which can be interpreted as an indication of “uniformizing” behavior of the flow.

Free and bound entanglement dynamics in qutrit systems under Markov and non-Markov classical noise

We investigate in detail the dynamics of decoherence, free and bound entanglements, and the conversion from one to another (quantum state transitions), in a two non-interacting qutrits system initially entangled and subject to independents or a common classical noise. Both Markovian and non-Markovian environments are considered. Furthermore, isotropic and bound entangled states for qutrits systems are considered as initial states. We show the efficiency of the formers over the latters against decoherence, and in preserving quantum entanglement. The loss of coherence increases monotonically with time up to a saturation value depending upon the initial state parameter and is stronger in a collective Markov environment. For the non-Markov regime the presence or absence of entanglement revival and entanglement sudden death phenomena is deduced depending on both the peculiar characteristics of the noise, the physical setup and the initial state of the system. We demonstrate distillability sudden death for conveniently selected parameters in bound entangled states; meanwhile, it is completely absent for isotropic states, where entanglement sudden death is avoided for dynamic noise independently of the noise regime and the physical setup. Our results indicate that distillability sudden death under the Markov/non-Markov noise considered can be avoided depending upon the physical setup.

Floquet Quantum Simulation with Superconducting Qubits

We propose a quantum algorithm for simulating spin models based on periodic modulation of transmon qubits. Using Floquet theory we derive an effective time-averaged Hamiltonian, which is of the general XYZ class, different from the isotropic XY Hamiltonian typically realised by the physical setup. As an example, we provide a simple recipe to construct a transverse Ising Hamiltonian in the Floquet basis. For a 1D system we demonstrate numerically the dynamical simulation of the transverse Ising Hamiltonian and quantum annealing to its ground state. We benchmark the Floquet approach with a digital simulation procedure, and demonstrate that it is advantageous for limited resources and finite anharmonicity of the transmons. The described protocol can serve as a simple yet reliable path towards configurable quantum simulators with currently existing superconducting chips.

Remote web-based control laboratories using embedded Linux and field-programmable gate array

In this article, the authors present a new approach based on the hardware and software architecture using embedded Linux and field-programmable gate array for implementation of remote laboratories. It combines a set of software and hardware resources in the interest of offering a multidisciplinary low-cost open platform for engineering education. Thus, the proposed approach allows students to develop low-cost and easily programmable prototypes of electrical systems control, robotics, and other embedded devices that feature Internet connectivity, Input/output, networking, and operating systems. In the proposed work, the authors present a codesign solution with flexible hardware devices, providing characteristics of multipurpose use with many experimental devices, and fully configurable graphical user interface. The physical setup and communication principles of hardware architecture are based on two types of devices: the Beaglebone running embedded Linux operating system and the field-programmable logic gate array. The graphical user interface is designed as a web page based on HTML and PHP programming languages; this allows the teachers/students to control the system easily, parameterize, and observe the behavior of the controller/system remotely.

Physical Versus Digital Sticky Notes in Collaborative Ideation

In this paper, we compare the use of physical and digital sticky notes in collaborative ideation. Inspired by a case study in a design company, we focus on a collaborative ideation task, which is often part of pair-wise brainstorming in design. For comparison and to focus on the different materiality, we developed a digital sticky notes setup designed to be as close to the physical setup as possible, not adding any advanced digital features, even though technology has reached a stage where more sophisticated use of digital sticky notes on digital boards is possible. In this paper, we present a study of ideation among pairs of experienced sticky note users. The ideation sessions were video recorded and analyzed to focus on how collaboration is supported across the two setups. Based on quantitative analyses of the participants’ interactions with the artefacts, talking patterns, position and attention during the sessions, we qualify how the differences and similarities between the 2 setups have an impact on note handling, ideation techniques, group dynamics and socio-spatial configuration, e.g. the use of the room, the boards and tables. We conclude that, while the physical setup seems more appropriate for creating notes and posting notes, the digital setup invites more note interaction. Nevertheless, we did not find significant differences in the ideation outcome (e.g., number of notes created) or how participants collaborated between the 2 setups. Hence, we argue that collaborative ideation can successfully be supported in a digital setup as well. Consequently, we believe that the next step in a technological setup is not an either or, but should bring the best of the two worlds together.

The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms.

Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter “cleaners”). Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right) in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.

The role of rural school libraries on childrens exposure to literacy in the Namibian context

The link between libraries and reading development has been found to be a determining factor in literacy development by scholars the world over. Based on the findings of a study on the constraints encountered by teachers in teaching English as a Second Language (ESL) in rural combined schools in the Oshana region, this paper analyses the role of school libraries in rural schools in Namibia. The study made use of the qualitative approach to investigate some of the causes of ineffective teaching and learning in rural schools. Each year, the Directorate of National Examinations and Assessments (DNEA) reveals poor academic performance in the National Senior Secondary Certificate examinations, particularly in the English subject. This study found that poor learner reading skills coupled with learners’ limited access to reading materials constrained the teaching of ESL. Although there were libraries at each school that participated in the study, physical set-up of the libraries often did not qualify them to be libraries in a prototypical definition of a library. It is introspection worthy to examine the role of these rural school libraries on children’s exposure to literacy in an environment of limited reading materials.

2017 Elijah High-Altitude Balloon Launch Team Summer Proceedings Report

The 2017 Wisconsin Space Grant Consortium Elijah High-Altitude Balloon Launch Team was comprised of one student from Lawrence University, two students from the Milwaukee School of Engineering, and one student from the University of Wisconsin – Fox Valley. This year, three members of the team had experience with high altitude balloon launches due to previous participation on either the Elijah Payload or Launch Team, or both. A training session was hosted by Dr. Farrow to familiarize or refresh the team with the physical setup of a launch train as well as how to run track predictions and how to read the jet stream charts. Launches were planned and carried out for the Elijah High-Altitude Balloon Payload Team. This launch was successful, reaching a peak altitude of over 115,000 ft (35 km) above mean sea level.

Use of information resources and services in the library of Zakir Husain Delhi College (Evening): A study

College library has to play a vital role in meeting the multi-dimensional demands of students and faculties for information and knowledge. The study focused on student's satisfaction regarding library resources and services at Zakir Husain Delhi College (Evening) library. It discusses the collections both print as well as electronic, basic facilities, physical setup, electronic or digital resources, traditional and ICT based services. The study found that 75.82% users are fully satisfied with overall resources and services of the college library, majority 83.44% users are using library for the purpose of lending materials, 79.30% users satisfied with Library OPAC, 72.33% with Circulation, only 16.78% are satisfied with internet facilities and 21.35% with online databases. The study suggested that College library should improve the internet facilities and organize a library orientation program at regular intervals in order to maximize the use of library resources and services especially e-resources.

Relationship of Montessori Approach with Interior Spaces in Preschools and Physical Set-up

Relationship of Montessori Approach with Interior Spaces in Preschools and Physical Set-up

Smartphone Application as a Media to Change of health Behavior (Diet / Physical Activity Setup), Literature Review

Smartphone Application as a Media to Change of health Behavior (Diet / Physical Activity Setup), Literature Review

Smartphone Application as a Media to Change of health Behavior (Diet / Physical Activity Setup), Literature Review

Smartphone Application as a Media to Change of health Behavior (Diet / Physical Activity Setup), Literature Review

Modeling Fuel Film Cooling on a Flat Plate

Cooling of liquid rocket engine combustion chambers and nozzles is a critical component to liquid rocket engine design. A common method of cooling is liquid-fuel film cooling. Liquid fuel is injected along the surface of the wall to act as a barrier against the core combustion gases. A numerical model is developed for simulating a physical experimental test setup meant to study liquid-fuel film cooling over a flat plate using a hydrocarbon fuel. The model incorporates turbulent multiphase flow with species transport within a commercial computational fluid dynamics software package. Conjugate heat transfer is simulated through walls containing embedded cooling channels. A novel user-defined function is written to incorporate reactions between the liquid fuel and the freestream gases. Comparisons are made between simulations with and without the phase interactions, as well as with simplifications to the cooling channel geometry. It was found necessary to model the cooling channel geometry in order to avoid artificially reducing cooling performance.

Wind-Driven Circulation in a Shelf Valley. Part I: Mechanism of the Asymmetrical Response to Along-Shelf Winds in Opposite Directions

AbstractMotivated by observations in Hudson shelf valley showing stronger onshore than offshore flows, this study investigates wind-driven flows in idealized shallow shelf valleys. This first part of a two-part sequence focuses on the mechanism of the asymmetrical flow response in a valley to along-shelf winds of opposite directions. Model simulations show that (i) when the wind is in the opposite direction to coastal-trapped wave (CTW) phase propagation, the shelf flow turns onshore in the valley and generates strong up-valley transport and a standing meander on the upstream side (in the sense of CTW phase propagation) of the valley, and (ii) when the wind is in the same direction as CTW phase propagation, the flow forms a symmetric onshore detour pattern over the valley with negligible down-valley transport. Comparison of the modeled upstream meanders in the first scenario with CTW characteristics confirms that the up-valley flow results from CTWs being arrested by the wind-driven shelf flow establishing lee waves. The valley bathymetry generates an initial excessive onshore pressure gradient force that drives the up-valley flow and induces CTW lee waves that sustain the up-valley flow. When the wind-driven shelf flow aligns with CTW phase propagation, the initial disturbance generated in the valley propagates away, allowing the valley flow to adjust to roughly follow isobaths. Because of the similarity in the physical setup, this mechanism of arrested CTWs generating stronger onshore than offshore flow is expected to be applicable to the flow response in slope canyons to along-isobath background flows of opposite directions.

Impact attenuation provided by shin guards for field hockey

Low-energy impact testing of hockey shin guards was carried out using a drop test impact rig and a new physical setup protocol. Two brands of shin guards were impacted once (2.6 J, 3.3 J; without and with a sock), and impacted three times (3.3 J; with a sock). The peak force and impulse of a single impact increased with increasing impact energy (by approximately 30 and 7%, respectively) whilst repeated impacts increased the peak force and decreased the impulse (by approximately 70 and 3–9%, respectively, between one and three impact events). The presence of a sock attenuated impact force to a greater extent than the guards alone, at both impact energies. As a sock is usually worn over hockey shin guards, its presence contributes to enhanced protection to the lower limb.

Experimental research on pedestrian lower leg impact

The present paper is centred on the research of deceleration measured at the level of the lower leg during a pedestrian impact in multiple load cases. Basically, the used methodology for physical test setup is similar to EuroNCAP and European Union regulatory requirements. Due cost reduction reasons, it was not used a pneumatic system in order to launch the lower leg impactor in the direction of the vehicle front-end. During the test it was used an opposite solution, namely the vehicle being in motion, aiming the standstill lower leg impactor. The impactor has similar specifications to those at EU level, i.e. dimensions, materials, and principle of measurement of the deceleration magnitude. Therefore, all the results obtained during the study comply with the requirements of both EU regulation and EuroNCAP. As a limitation, due to unavailability of proper sensors in the equipment of the lower leg impactor, that could provide precise results, the bending angle, the shearing and the detailed data at the level of knee ligaments were not evaluated. The knee joint should be improved for future studies as some bending angles observed during the post processing of several impact video files were too high comparing to other studies. The paper highlights the first pedestrian impact physical test conducted by the author, following an extensive research in the field. Deceleration at the level of pedestrian knee can be substantially improved by providing enough volume between the bumper fascia and the front-end structure and by using pedestrian friendly materials for shock absorbers, such as foams.

Three-dimensional numerical investigation of flow through screens as energy dissipators

Screens, perforated units to dissipate energy in hydraulic structures, are investigated numerically in this study. These units are part of a physical setup exposed to supercritical flows, normally created by sluice gates. The interaction of perforated screens and supercritical flows results in local complex three-dimensional flows, which can be analyzed by the application of RANS-based flow equations. The most important controlling parameters include supercritical Froude number between 2 and 10 and screen porosity of 40% and 50%. Numerical water surface profiles and energy dissipation are validated by the author’s experimental data. This paper derives a set of equations in terms of depth ratio of the hydraulic jump through the perforated screens and assesses the effect of baffles on energy dissipation. This study seeks a proof-of-concept for the application of the RANS-based technique for further application of the result to real hydraulic structures in due course.

Procedure to measure real time latency using software defined radio in a W‐band fiber‐wireless link

AbstractReducing latency is a major challenge for current telecommunications systems. 5G networks are envisioned to achieve end‐to‐end latencies below 1 ms, thus enabling the Internet of Things (IoT) evolution and new applications such as Tactile Internet. In this article, we present a new procedure to measure real time latency in hybrid optical‐wireless links. We obtained 2 ms end to end latency using Software Defined Radio to measure latency in a physical setup. We tested the procedure on W‐band fiber‐wireless link and validated the results against PING over GRE tunnel.

Spanwise Particle Clusters in DNS of Sediment Transport Over a Regular and an Irregular Bed

The paper presents a comparison of two phase-resolving simulations of heavy particles in a turbulent open-channel flow to investigate the impact of the regularity of the underlying sediment bed on both the fluid and the particle phase. While a regular sediment bed is common practice for both experimental and numerical studies, it may introduce over-idealized conditions in the physical setup, which is investigated by juxtaposing these results with those obtained using a particularly designed irregular bed. It is found that the overall transport mode remains unchanged, but the configuration of the sediment bed has an impact on various statistical quantities that show quantitative differences for the two considered cases. The disturbed irregular bed enhances turbulent fluctuations and promotes formation of particle clusters as well as the resuspension of particles. It is shown that this change in the configuration yields more realistic results resembling bedforms such as subaqueous dunes that may be observed on the field-scale. The proposed type of irregularity constitutes a benchmark to investigate this issue in further experiments and simulations.

Psychological and physiological human responses to simulated and real environments: A comparison between Photographs, 360° Panoramas, and Virtual Reality

Psychological research into human factors frequently uses simulations to study the relationship between human behaviour and the environment. Their validity depends on their similarity with the physical environments. This paper aims to validate three environmental-simulation display formats: photographs, 360° panoramas, and virtual reality. To do this we compared the psychological and physiological responses evoked by simulated environments set-ups to those from a physical environment setup; we also assessed the users' sense of presence. Analysis show that 360° panoramas offer the closest to reality results according to the participants' psychological responses, and virtual reality according to the physiological responses. Correlations between the feeling of presence and physiological and other psychological responses were also observed. These results may be of interest to researchers using environmental-simulation technologies currently available in order to replicate the experience of physical environments.