Eddy resolving simulation of mixed convection in a rotating annular cavity with one heated disk and axial throughflow: the effect of the surface macro-relief

We present the results of hybrid RANS/LES computations of non-isothermal buoyant flow in a rapidly revolving enclosure with paraxial transit stream of the cooling air. Foil heat flux meters mounted on the disk surface in the base experiment are mimicked by means of the grid resolved macro-relief. The results obtained using the relief and smooth disk models are collated with available measurements. According to the simulation, the addition of the relief has resulted in switching from two to three pairs of cyclonic/anti-cyclonic global circulations, and the overall heat transfer rate has increased by 20%. It has been found also that the sensor readings can be up to 25% higher than the heat flux averaged over the circumference at the same radius. Despite this distinct effect of the surface relief, the local heat transfer rate is still underestimated considerably as compared to measurements.

A Velostat-Based Pressure-Sensitive Mat for Center-of-Pressure Measurements: A Preliminary Study

Center-of-pressure (CoP) displacements play a key role in studies assessing postural stability. The accepted instrument to measure CoP trajectories is the force platform, but pressure-sensitive mats (PSMs) are an alternative composed of a matrix of sensitive cells. A typical cell comprises two electrodes with piezoresistive material in between, while a force platform has a force sensor at each of its corners. In this paper, we compare a homemade Velostat-based PSM and an affordable commercial mat with a commercial force platform in a test series with 42 healthy volunteers in single-legged trials (29 males, 13 females; height 1.74 (0.09) m, weight 74.3 (16.34) kg, age 31.21 (12.66) years). The aim of the research was to perform a preliminary study of the performance of our prototype to measure CoP, and more specifically, the standard deviation of the CoP path on both axes, the medial–lateral and anterior–posterior. We could thus discover several improvements for future clinical applications. The intraclass correlation coefficient (ICC) for agreement in the base experiment showed a moderate value for the prototype (0.38 to 0.63) and lower values for the commercial mat (0.11 to 0.12). However, we identified several factors that were relevant to improve ICC and reduce error by considering several processing options: (i) the known crosstalk problem between cells that appears in this kind of mats must be eliminated; (ii) the response time of the sensor has to be taken into account; and (iii) increasing the mat resolution also improves agreement. Therefore, as future work, we plan to test the improved version of the prototype in a clinical environment.

Study on Wavelet Entropy for Airport Pavement Inspection using a Multi-Static GPR System

The multi-layer nature of airport pavement structures is susceptible to the generation of voids at the bonding parts of the structure, which is also called interlayer debonding. Observations have shown that the thickness of the resulting voids is usually at the scale of millimeters, which makes it difficult to inspect. The efficient and accurate characteristics of ground penetrating radar (GPR) make it suitable for large area inspections of airport pavement. In this study, a multi-static GPR system was used to inspect the interlayer debonding of a large area of an airport pavement. A special antenna arrangement can obtain common mid-point (CMP) gathers during a common offset survey. The presence of interlayer debonding affects the phase of the reflection signals, and the phase disturbance can be quantified by wavelet transform. Therefore, an advanced approach that uses the average entropy of the wavelet transform parameters in CMP gathers to detect the interlayer debonding of airport pavement is proposed. The results demonstrate that the regions with high entropy correspond to the regions where tiny voids exist. The new approach introduced in this study was then evaluated by a field-base experiment at an airport taxiway model. The results show that the proposed approach can detect interlayer debonding of the pavement model accurately and efficiently. The on-site coring results confirm the performance of the proposed approach.

Demon or angel: an exploration of gamification in management

Purpose Previously coined as the application of gaming principles in non-gaming scenarios, gamification is an emerging managerial tactic, but it lacks a rigorous theorization in the management discipline. Based on introductive research on related domains, this study aims to link up gamification and training and directly explored its effectiveness and efficacy, thus providing certain implications for practitioners. Specifically, this paper conceptualizes the gamification as a crystallization of routines as it continuously strengthens the new ways to award and punish with predetermined goals while initiated from past experiences. As such, the study confirms that gamification demotivates the participants and lowers their performances. Overall, the study is important as it investigates the significance of gamification and offers a new perspective to disentangle the debates over the effect of experience on learning. Design/methodology/approach The study used one base experiment conducted in two random-chosen paired classes, followed by another confirmative experiment. By introducing the gamification system into one experiment class while controlling the other, the authors sent out two waves of surveys while merging with the objective grades to investigate the effects of gamification on both motivation and performance. Findings The results have confirmed that gamification could engender the detrimental effects on both motivation and performance, though the authors did not find support for a mediating effect of motivation on the relationship between gamification and performance. Research limitations/implications Because of resource limitation, the study used business students’ academic performance as a proxy for the performance effect. Although the results help reveal a basic cause-effect relationship, we still need further experiments based on real business units and/or on larger samples. Practical implications The findings indicate that gamification counter-intuitively demotivates participants and directly leads to poorer performances. This reminds practitioners of a cautious adoption of gamification in their management system. Originality/value To the best of authors’ knowledge, this study is among the first to link the trendy concept of gamification with both managerial and academic studies on related fronts.

ON THE INFLUENCE ORGANIC COMPONENTS OF THE EXTRACT OF HERACLEUMON FLOTATION OF GOLD-BEARING SULPHIDES

The complexing, sorption and flotation properties of the organic extract of the green mass of Heracleum Sosnovsky (BO) containing sulphide gold-bearing minerals were investigated. The sorption and elemental composition of the surface of the minerals before and after contact with the reagent BO were studied on polished sections using an LEO 1420VP analytical scanning electron microscope (ASEM) equipped with an X-ray energy dispersive microarray analyzer INCA 350 and a KEYNCE laser microscope with VK-9700. The sorption of furocoumarines on the surface of chalcopyrite and gold particles after their contact with the organic extract of BO was determined by a spectrophotometric method and thin-layer chromatography (TLC). By flotation studies using monomineralic powders FeS2 and CuFeS2, as well as minerals with artificially deposited gold (FeS2Au and CuFeS2Au), the flotation activity of the BO extract with respect to the gold-bearing pyrite and chalcopyrite was revealed. When flotation gold-bearing sulphide ore with the use of BO as an additional collector, an increase in the quality of the concentrate with respect to gold content up to 10.8 g / t and gold recovery into concentrate to 82.69% was found, which is 3% higher than in the base experiment. The obtained results give grounds to talk about the possibility of using the flotation of a poisonous species of Heracleum after isolation from it of natural chemical compounds possessing surface-active properties with respect to gold-bearing sulfide minerals. The extraction of an extract containing furocoumarines from the Heracleum is not a problem.

GINGER

Gyroscopes IN General Relativity (GINGER) is a proposal of an Earth-base experiment to measure the Lense–Thirring effect. GINGER uses an array of ring lasers, which are the most sensitive inertial sensors to measure the rotation rate of the Earth. GINGER is based on a three-dimensional array of large size ring lasers, able to measure the de Sitter and Lense–Thirring effects. The instrument will be located in the INFN Gran Sasso underground laboratory, in Italy. We describe preliminary developments and measurements. Earlier prototypes based in Italy, GP2, GINGERino, and G-LAS are also described and their preliminary results reported.

The Strength Quantum Theory for Crystals with Nanodefects

The article examines the impact of nanodefects on the reduction of the crystals strength. A summary of the authors research results is illustrated by the analysis example of the NaCl crystal destruction process from the standpoint of strength quantum theory. As the base experiment is seen testing the dry and wet a salt crystal made by academician A. Ioffe. The authors research aim was a little-studied patterns of the crystal lattice destruction quantum mechanism. The article gives a brief historical background of the research in this area. The first section discusses the rystal cell dynamic characteristics change as a result of destruction. Assesses self-resonant frequency of an atom at a lattice point of the crystal before and after the destruction. In the second section of the article examines the relationship between the natural frequencies of the atoms in the lattice and elastic energy wich accumulated in the crystal body in the force loading process. The main attention is paid to theoretical modeling of the links strength between atoms in the crystal surface layer. We study the strength dependence of these relationships to the availability of nanodefects on the crystal surface. There are modeled bond strength to clean the crystal surface, as a result of the surface lattice electrification when atoms capture free electrons and for the case when jobs of atoms in the crack are filled with the external environment atoms. The calculations confirm the validity of the proposed theoretical model of reduction or the hanging of the crystals strength by the atoms interaction with the external environment.

Inquiry Base Experiment: The Effect of Plasma on Glass Surface Properties

In this paper we present an experiment for the undergraduate plasma processing course. Students were exposed to a laboratory experience that very closely resembles real-life research by performing surface modification experiments using gas discharge plasma. This experiment demonstrates to students the effect of plasma on surface properties.