On new symplectic elasticity approach for exact bending solutions of rectangular thin plates with two opposite sides simply supported

AbstractThis paper presents a bridging research between a modeling methodology in quantum mechanics/relativity and elasticity. Using the symplectic method commonly applied in quantum mechanics and relativity, a new symplectic elasticity approach is developed for deriving exact analytical solutions to some basic problems in solid mechanics and elasticity which have long been bottlenecks in the history of elasticity. In specific, it is applied to bending of rectangular thin plates where exact solutions are hitherto unavailable. It employs the Hamiltonian principle with Legendre’s transformation. Analytical bending solutions could be obtained by eigenvalue analysis and expansion of eigenfunctions. Here, bending analysis requires the solving of an eigenvalue equation unlike in classical mechanics where eigenvalue analysis is only required in vibration and buckling problems. Furthermore, unlike the semi-inverse approaches in classical plate analysis employed by Timoshenko and others such as Navier’s solution, Levy’s solution, Rayleigh–Ritz method, etc. where a trial deflection function is pre-determined, this new symplectic plate analysis is completely rational without any guess functions and yet it renders exact solutions beyond the scope of applicability of the semi-inverse approaches. In short, the symplectic plate analysis developed in this paper presents a breakthrough in analytical mechanics in which an area previously unaccountable by Timoshenko’s plate theory and the likes has been trespassed. Here, examples for plates with selected boundary conditions are solved and the exact solutions discussed. Comparison with the classical solutions shows excellent agreement. As the derivation of this new approach is fundamental, further research can be conducted not only on other types of boundary conditions, but also for thick plates as well as vibration, buckling, wave propagation, etc

Dynamic multivalent recongnition of cyclodextrin vesicles

Cyclodextrin bilayer vesicles have dynamic membranes that recognize guest molecules through efficient multivalent host–guest interaction reminiscent of multivalent binding of a ligand with receptors in a biological membrane

The use of non-intrusive user logging to capture engineering rationale, knowledge and intent during the product life cycle

Within the context of Life Cycle Engineering it is important that structured engineering information and knowledge are captured at all phases of the product life cycle for future reference. This is especially the case for long life cycle projects which see a large number of engineering decisions made at the early to mid-stages of a product's life cycle that are needed to inform engineering decisions later on in the process. A key aspect of technology management will be the capturing of knowledge through out the product life cycle. Numerous attempts have been made to apply knowledge capture techniques to formalise engineering decision rationale and processes; however, these tend to be associated with substantial overheads on the engineer and the company through cognitive process interruptions and additional costs/time. Indeed, when life cycle deadlines come closer these capturing techniques are abandoned due the need to produce a final solution. This paper describes work carried out for non-intrusively capturing and formalising product life cycle knowledge by demonstrating the automated capture of engineering processes/rationale using user logging via an immersive virtual reality system for cable harness design and assembly planning. Associated post-experimental analyses are described which demonstrate the formalisation of structured design processes and decision representations in the form of IDEF diagrams and structured engineering change information. Potential future research directions involving more thorough logging of users are also outlined

STARA fight or flight: a two-wave time-lagged study of challenge and hindrance appraisal of STARA awareness on basic psychological needs and individual competitiveness productivity among hospitality employees

The introduction of smart technologies, artificial intelligence, robotics, and algorithms (STARA) has changed the workforce significantly, with many concerns about its impact on employees. This study elucidates how one’s appraisal of this situation would influence basic psychological needs and individual competitiveness productivity. Using a two-wave time-lagged study, data collected from 224 hospitality employees was examined using the partial least squares method structural equation modelling (PLS-SEM). Results suggested that individual appraisal towards STARA awareness has differential outcomes towards satisfying basic psychological needs. Among the three basic psychological needs, the needs for relatedness and competency were positively related to individual competitive productivity (ICP). We extend extant studies by incorporating challenge-hindrance framework and self-determination theory (SDT) in the context of the future of work involving STARA. It advances the body of knowledge in understanding a more fundamental issue of how STARA can bring out the best in employees, how STARA shapes employees’ opinions and perspectives of the work they are doing, and what they should do to work alongside STARA

Activity profiles in adolescent netball: A combination of global positioning system technology and time-motion analysis

Purpose: This study sought to understand the activity profiles of adolescent netball players in match play conditions. To date there has been no published research in this area and such findings would give important insights to inform the training and preparation of adolescent netball players. Methods: Twenty-two adolescent netball players (age 14.5 ± 0.5 y, stature 165 ± 5 cm, body mass 58.32 ± 7.43 kg) were analysed while competing in a specially arranged outdoors match of 6 x 10 min periods. The players were categorised into one of three positional groups. To track the players’ movement GPS units were worn located between the scapulas in a purpose built harness. The match was filmed so that post-match time-motion analysis could be carried-out. Both the GPS and time-motion analysis data was classified into one of six movement categories for analysis. Results: Midcourt players covered the greatest distance per quarter (37.73 ± 17.39 m/min) with the Attacking players covering the least distance (35.42 ±11.66 m/min). The Attacking players covered the greatest distance per quarter through sprinting (8.5 ±16.2 m/qtr), travelling nearly twice the distance of the other two groups. When comparing the mean frequency and duration of movements from the GPS and time-motion analysis, there was a discrepancy between the two methods. Conclusions: The results from this study suggest that in adolescent netball Midcourt players cover the greatest distance per quarter while Attacking players cover the greatest distance through sprinting. A comparison between data from the GPS and time-motion analysis suggest that the GPS units used in this study under report the frequency and duration of high intensity movements

Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube

We have studied the afterpulse of a hemispherical photomultiplier tube for an upcoming reactor neutrino experiment. The timing, the amplitude, and the rate of the afterpulse for a 10 inch photomultiplier tube were measured with a 400 MHz FADC up to 16 \ms time window after the initial signal generated by an LED light pulse. The time and amplitude correlation of the afterpulse shows several distinctive groups. We describe the dependencies of the afterpulse on the applied high voltage and the amplitude of the main light pulse. The present data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure

Characterization of the QUartz Photon Intensifying Detector (QUPID) for Noble Liquid Detectors

Dark Matter and Double Beta Decay experiments require extremely low radioactivity within the detector materials. For this purpose, the University of California, Los Angeles and Hamamatsu Photonics have developed the QUartz Photon Intensifying Detector (QUPID), an ultra-low background photodetector based on the Hybrid Avalanche Photo Diode (HAPD) and entirely made of ultraclean synthetic fused silica. In this work we present the basic concept of the QUPID and the testing measurements on QUPIDs from the first production line. Screening of radioactivity at the Gator facility in the Laboratori Nazionali del Gran Sasso has shown that the QUPIDs safely fulfill the low radioactive contamination requirements for the next generation zero background experiments set by Monte Carlo simulations. The quantum efficiency of the QUPID at room temperature is > 30% at the xenon scintillation wavelength. At low temperatures, the QUPID shows a leakage current less than 1 nA and a global gain of 10^5. In these conditions, the photocathode and the anode show > 95% linearity up to 1 uA for the cathode and 3 mA for the anode. The photocathode and collection efficiency are uniform to 80% over the entire surface. In parallel with single photon counting capabilities, the QUPIDs have a good timing response: 1.8 +/- 0.1 ns rise time, 2.5 +/- 0.2 ns fall time, 4.20 +/- 0.05 ns pulse width, and 160 +/- 30 ps transit time spread. The QUPIDs have also been tested in a liquid xenon environment, and scintillation light from 57Co and 210Po radioactive sources were observed.Comment: 15 pages, 22 figure

Analysis of Various Polarization Asymmetries In The Inclusive b→sℓ+ℓ−b\to s \ell^+ \ell^- Decay In The Fourth-Generation Standard Model

In this study a systematical analysis of various polarization asymmetries in inclusive b \rar s \ell^+ \ell^- decay in the standard model (SM) with four generation of quarks is carried out. We found that the various asymmetries are sensitive to the new mixing and quark masses for both of the $\mu$ and $\tau$ channels. Sizeable deviations from the SM values are obtained. Hence, b \rar s \ell^+ \ell^- decay is a valuable tool for searching physics beyond the SM, especially in the indirect searches for the fourth-generation of quarks ($t', b')$.Comment: 19 Pages, 10 Figures, 3 Table

A new methodology to evaluate the performance of physics simulation engines in haptic virtual assembly

Purpose – In this study, a new methodology to evaluate the performance of physics simulation engines (PSEs) when used in haptic virtual assembly applications is proposed. This methodology can be used to assess the performance of any physics engine. To prove the feasibility of the proposed methodology, two-third party PSEs – Bullet and PhysXtm – were evaluated. The paper aims to discuss these issues. Design/methodology/approach – Eight assembly tests comprising variable geometric and dynamic complexity were conducted. The strengths and weaknesses of each simulation engine for haptic virtual assembly were identified by measuring different parameters such as task completion time, influence of weight perception and force feedback. Findings – The proposed tests have led to the development of a standard methodology by which physics engines can be compared and evaluated. The results have shown that when the assembly comprises complex shapes, Bullet has better performance than PhysX. It was also observed that the assembly time is directly affected by the weight of virtual objects. Research limitations/implications – A more comprehensive study must be carried out in order to evaluate and compare the performance of more PSEs. The influence of collision shape representation algorithms on the performance of haptic assembly must be considered in future analysis. Originality/value – The performance of PSEs in haptic-enabled VR applications had been remained as an unknown issue. The main parameters of physics engines that affect the haptic virtual assembly process have been identified. All the tests performed in this study were carried out with the haptic rendering loop active and the objects manipulated through the haptic device.CONACYT (National Science and Technology Council of Mexico) research grant CB-2010-01-154430 and EPSRC/IMRC grants 113946 and 11243