Miracle-dz/UniFAR-FTUs huggingface dataset:
A new mechanism for rapid transition involving a pair of oblique waves

A pair of small but finite‐amplitude oblique waves were used as initial condition in numerical simulations of transition to turbulent flow. A rapid energy growth to a transition peak occurred. Although this transition scenario is triggered by a nonlinear interaction, the dominant mechanism yielding substantial disturbance amplitudes was found to be linear. A number of simulations were made that showed that the overall features of this transition scenario remains the same for a range of parameter values.
A Numerical Study of a Low-level Jet and Its Accompanying Secondary Circulation in a Mei-Yu System

Abstract A primitive equation numerical model has been used to study the Mei-Yu system that occurred in the middle of May 1987. Although cumulus heating was not included in one of the experiments, all of the major features of a Mei-Yu system other than deep convection are reproduced in that experiment. These features are a cloud band along the coastline in southern China; a weak temperature gradient, a strong moisture gradient, and a strong wind shear across the cloud band; and a supergeostrophic low-level jet (LLJ) with an accompanying secondary circulation. When the moist air coming from the south encounters the migrating high pressure system in the north, it turns to the east-northeast and becomes saturated. The resulting stratiform cloud covers all of southern China and the pressure trough at the 850-hPa level deepens by 1.5 hPa due to the latent heat released. It induces convergent motion in the lower level and generates a direct, cross-frontal secondary circulation that helps keep the low-level wind.
Wide-field high-resolution solid immersion fluorescence microscopy applying an aplanatic solid immersion lens

The use of aplanatic solid immersion lenses (ASILs) made of high refractive index optical materials provides a route to wide-field high-resolution optical microscopy. We analyze the aberrations that need to be circumvented for wide-field, high-resolution imaging by hybrid optical simulations based on both ray and wave optics. The conclusions on the relationships among ASIL size, fluorescence imaging spectral width, and field of view not only guide us to design the microscopic system demonstrated in this article, but also clearly demonstrate the general design considerations necessary when applying an ASIL in fluorescence microscopy. Based on the simulation results, we develop wide-field high-resolution solid immersion fluorescence (SIF) microscopy employing an ASIL with an effective numerical aperture (NA) of 1.85. We demonstrate wide-field, high-resolution imaging of synthetic and biological samples with our SIF system. In the presence of a gap between the ASIL and the sample, we experimentally demonstrate that the effective NA of the SIF system is determined by the refractive index of the gap medium in addition to that of the ASIL material; thus, in general, degrading the resolution. Future developments of the SIF system to suit routine use and make it achieve still higher resolution by combining SIF and other microscopic techniques are proposed.
Why first order quantum phase transitions are interesting

It is frequently argued that only second order phase transitions at T = 0 deserve to be called quantum phase transitions, while first order quantum phase transitions are a contradiction in terms. However, quantum phase transitions differ from classical phase transitions in two fundamental ways. First, the free energy landscape need not be that of a classical second order phase transition for quantum fluctuations to drive the transition. Second, at T = 0 a rich variety of quantum correlation effects, such as magnetic rotons, instantons or skyrmion textures, are possible. The recent discovery of partial magnetic order, an extended non-Fermi liquid phase and superconductivity at the first order quantum phase transitions of itinerant-electron magnets underscore the need for detailed experimental studies of hitherto unexplored weak rigidities that are well known to generate first order behaviour. These include changes of the electronic valence, spin–orbit coupling, crystal electric field levels, and crystallographic structure driven by instabilities of the Fermi surface.
PID CONTROLLER TUNING FOR BILINEAR CONTINUOUS TIME INVARIANT MIMO SYSTEM

Abstract This paper presents a technique for optimal tuning of continuous time PID controller for bilinear MIMO plant with piecewise constant input signals. The proposed technique is based on minimization of quadratic proximity criterion applied for transient processes of open-loop control system and its implicit reference model (internal model control). The tuning algorithm for controller parameters uses estimates of bilinear MIMO plant parameters. The algorithm of parametric identification is used for determining the bilinear plant parameters. The PID controller optimal tuning algorithm for bilinear continuous time MIMO system is presented. A numerical example of two-channel bilinear MIMO plant control using two-channel PI controller is considered. It shows good controller performance within given range of coordinate and parametric disturbance.
Detection of saliva-range glucose concentrations using organic thin-film transistors

We describe the development of a glucose sensor through direct incorporation of an enzyme (glucose oxidase) into the gate of an organic thin film transistor (OTFT). We show that glucose diffusion is the key determinant of the device response time and present a mechanism of glucose sensing in these devices that involves protonic doping of the transistor channel via enzymatic oxidation of glucose. The integrated OTFT sensor is sensitive across 4 decades of glucose concentration; a range that encompasses both the blood and salivary glucose concentration levels. As such, this work acts as a proof-of-concept for low-cost printed biosensors for salivary glucose.
An investigation of wall effects on hot-wire measurements using a bent sublayer probe

The effects of aluminium and Perspex walls on near-wall hot-wire measurements were investigated in a fully developed channel flow of 250 mm width, 1.6 mm (laminar) or 16.6 mm (turbulent) height using specially made bent sublayer probes of 5 m, 1.27 m and 0.63 m diameter that had minimum aerodynamic interference. Previous experiments by Wills indicated that the heat loss from the wire expressed in terms of Nusselt number (Nu) versus the Reynolds number ( based on velocity at the wire location and wire diameter) for various fixed distances from the wall does not converge to the wall-remote behaviour at large or (the distance from the wall normalized by the viscous length scale). Other works show conflicting trends of the effects of wall thermal conductivity, wire diameters and overheat ratio on the operation of the hot wire in the vicinity of the wall. The present effort represents a systematic approach to evaluate each of these parameters on the hot-wire performance near the wall in terms of Nu and measured dimensionless velocity (taken wrt wall shear velocity) for comparison to previous works and to resolve some of the apparent controversies. Experiments were also conducted in both fully developed laminar and turbulent channel flows to determine the near-wall correction curves in order to resolve the contradictory suggestions by Wills, Demin and Kuraev, and Zemskaya et al regarding laminar and turbulent near-wall corrections. The present investigations found that contrary to the previous work of Wills, the behaviour of Nu versus for a hot wire at given fixed distances from the wall converges to the wall-remote condition for large or . This finding was consistent for the three different wire diameters used and two walls of different thermal conductivities. The discrepancy with Wills' results is attributed to aerodynamic interference and blockage effects caused by the near-wall hot-wire prongs in a narrow channel flow. The critical distances from the wall, , beyond which the wall influences on hot-wire measurements can be considered insignificant, were found to decrease with decreasing wire diameter and decreasing wall thermal conductivity. They were found to be approximately 5.0, 3.7, 3.0 for the aluminium wall and 3.0, 2.7, 2.2 for the Perspex wall for respective wire diameters of 5 m, 1.27 m, 0.63 m. It was also found that the overheat ratio plays an insignificant role provided that the length to diameter ratio of the wire is sufficiently larger than 200 to minimize three-dimensional effects. The resultant mean distribution wrt obtained in fully developed channel flow was found to resemble the counterpart obtained in laminar flow. This finding concurs with the experimental results of Zemskaya et al performed in boundary layer flows, but contradicts the conclusion by Wills who recommended half the laminar correction for turbulent flow. It is suspected that the experimental results of Wills are affected by different degrees of prong interference and blockage effects for the laminar and turbulent channel flows which may account for the discrepancy.
Heat and Mass Transfer in a Falling Film Absorber of Ammonia—Water Absorption Systems

Abstract For ammonia-water generator-absorber heat exchanger (GAX) systems to work at high coefficient of performance, the heat and mass transfer components have to operate at optimum performance within a narrow range of conditions for the recovery of internal energy, in the present work, an analysis is performed to study the absorption process of an ammonia-water vapor mixture by an aqueous solution of ammonia in a falling film absorber. The combined heat and mass transfer processes involved arc analyzed through an integral formulation of the continuity, momentum, energy, and diffusion equations. The effects of vapor flow direction relative to the solution, cooling ability, ammonia concentration of solution and vapor, and interfacial momentum and heat transfer rate on absorption processes are investigated. The characteristics of the absorption process are found to be governed by the relative significance of the mass transfer resistance and the driving forces between the solution film and the vapor mixture.
Current-Constrained Adaptive Robust Control for Uncertain PMSM Drive Systems: Theory and Experimentation

In this article, we investigate the speed tracking control problem for permanent magnet synchronous motor (PMSM) drive systems. In particular, the current constraint, parametric uncertainties, and the external load disturbance are addressed simultaneously. To deal with these issues, we first propose a system transformation scheme, which equivalently transforms a PMSM system with the current constraint into the one without any constraints, thereby reducing the difficulties in the controller design caused by the current constraint. Based on the transformed system, the adaptive parameter estimation and robust control are integrated to derive a current-constrained adaptive robust controller (CCARC), which guarantees robust tracking performance under the current constraint, parametric uncertainties and external load disturbance. For the closed-loop system, the Lyapunov-based analysis is provided to show convergence and stability. Finally, the effectiveness of the proposed method is experimentally validated using a 5.5 kW PMSM.
Looking after children in secure settings: recent themes

AbstractThis article begins by looking at the various kinds of secure setting, and the legislation that allows children to be locked up. It moves on to examine, with reference to recent research, the reasons children are detained in secure conditions. The behavioural problems presented by the child, and the social and legal systems which aim to ensure that secure provision is used only when absolutely necessary, have an important bearing on the decision to place a child in secure accommodation. While there is agreement that the use of secure provision is sometimes justified, its use could be reduced through the expansion of appropriate alternative open provision. It is argued that the role of secure provision is still very unclear and poorly managed as a national resource. Secure units often function in isolation and are poorly integrated with other child-care resources. Some young people are moved from placement to placement in an attempt to avoid admission to secure provision, resulting in further damage to themselves and others. There seems to be a failure in the legislation to distinguish between young people who require a short stay in security during a crisis, from those who require a longer stay in an attempt to deal with long-standing antisocial and self-destructive behaviours. This problem has been compounded by the failure to develop an accepted methodology for understanding the behavioural problems presented by this group of young people. The creation of a national agency with specific responsibility for the administration and development of secure provision may help to resolve some of these problems.
Groupoids and Van Kampen's Theorem

Introduction The fundamental groupoid TT(X) of a topological space X has been known for a long time but has been regarded, usually, as of little import in comparison with the fundamental group—for example, the groupoid is described in ((3) 155) as an 'interesting curiosity'. In this paper we shall generalize the fundamental group at a point a of X, namely 7r(X,a), to the fundamental groupoid on a set A, written TT(X, A), which consists of the homotopy classes of paths in X joining points of A n X. If a e A, the fundamental group TT{X,O) can be recovered from knowledge of n(X,A), but the latter groupoid is often easier to describe because the category of groupoids has exactly the right properties to model successfully the geometric constructions in building up spaces. As an example of this, consider an adjunction space Bu^Z, where / : Y -> B is continuous and Y is a closed subspace of Z (so that B\JfZ is obtained by glueing Z to B by means of/) . The following is a basic step in computing the fundamental group of a space: Compute the fundamental group of B\JfZ in terms of the fundamental groups of B, Y, Z and the maps induced by i: Y -» Z, f: Y -y B. This is insoluble without some local conditions on Y in Z, as an example of H. B. Griffiths (6) shows. With suitable local conditions (and other topological conditions which may be regarded as inessential) a special case of this problem was solved by van Kampen in (10). His answer was a formula describing the fundamental group of B \JfZ in terms of generators and relations. We shall use groupoids to give in Theorem 4.2 a general and natural solution to this problem. With this theorem one can derive by a uniform method the fundamental groups of spaces from a large class which includes all CW-complexes, and, a fortiori, all simplicial complexes. Even for the latter spaces the methods here are simpler than the classical combinatorial methods. Theorem 4.2 is a deduction from our main result, Theorem 3.4, which determines a groupoid TT(X, AO) when X is the union of the interiors of two sets Xlt X2. Other work on the fundamental group of a union has been done by P. Olum (11), the author (1), R. H. Crowell (2), and A. I. Weinzweig (12). The results of (11) and (1) are not as powerful
Proteotyping of Campylobacter jejuni by MALDI-TOF MS and Strain Solution Version 2 Software

Identification of microorganisms by MALDI-TOF MS has become a popular method in the past 20 years. Strain Solution ver. 2 software appended with MALDI-TOF MS enables accurate discrimination of serotypes and strains beyond the genus and species level by creating a theoretical mass-based database. In this study, we constructed a theoretical mass database with the validated biomarkers to proteotype Campylobacter jejuni. Using 10 strains belonging to Campylobacter spp. available from culture collections and 41 Campylobacter jejuni strains isolated from humans and foods, the ribosomal protein subunits L36, L32, S14, L24, L23, L7/L12, and S11 could be selected as the effective biomarkers for the proteotyping of C. jejuni at MALDI-TOF MS. An accurate database of their theoretical mass-based values was constructed by matching these gene DNA sequences and the observed mass peaks. We attempted to automatically classify 41 strains isolated from nature using this database and Strain Solution ver. 2 software, and 38 strains (93%) were correctly classified into the intended group based on the theoretical mass-based values. Thus, the seven biomarkers found in this study and Strain Solution ver. 2 are promising for the proteotyping of C. jejuni by MALDI-TOF MS.
Neuromorphic control of a simulated 7-DOF arm using Loihi

In this paper, we present a fully spiking neural network running on Intel’s Loihi chip for operational space control of a simulated 7-DOF arm. Our approach uniquely combines neural engineering and deep learning methods to successfully implement position and orientation control of the end effector. The development process involved four stages: (1) Designing a node-based network architecture implementing an analytical solution; (2) developing rate neuron networks to replace the nodes; (3) retraining the network to handle spiking neurons and temporal dynamics; and finally (4) adapting the network for the specific hardware constraints of the Loihi. We benchmark the controller on a center-out reaching task, using the deviation of the end effector from the ideal trajectory as our evaluation metric. The RMSE of the final neuromorphic controller running on Loihi is only slightly worse than the analytic solution, with 4.13% more deviation from the ideal trajectory, and uses two orders of magnitude less energy per inference than standard hardware solutions. While qualitative discrepancies remain, we find these results support both our approach and the potential of neuromorphic controllers. To the best of our knowledge, this work represents the most advanced neuromorphic implementation of neurorobotics developed to date.
Stimulation of Polariton Photoluminescence in Semiconductor Microcavity

Photoluminescence at low temperature is studied for a CdTe-based microcavity tuned to resonance with a quantum well exciton. Two distinct stimulation effects are observed with increasing excitation. The first one is associated with the lower polariton state in the strong exciton-photon coupling regime. This effect, whose physical origin has not yet been identified, could be favored by the higher stability of exciton in CdTe. The second stimulation, obtained for much higher excitation, can be assigned to the electron-hole plasma in the weak coupling regime.
Shaping photoluminescence spectra with magnetoelectric resonances in all-dielectric nanoparticles

We measure the near-infrared photoluminescence spectra of colloidal quantum dots coupled to the localized electric and magnetic resonances of subwavelength silicon nanodisks. The spectral position of the resonances with respect to each other is controlled via the nanodisk geometry. We observe a strong influence of the nanodisk resonance positions on the quantum dot photoluminescence spectra. For separate resonances, the spectral density observed in transmittance measurements correlates with the spectral range covered by a broad emission spectrum. For the case of spectral overlap of the electric and magnetic dipolar resonances we enter a new regime for coupling, where the characteristic transparency effect evident in the transmittance spectra is accompanied by a pronounced single emission maximum. Our experimental observations are in good qualitative agreement with numerical calculations.
Acceleration efficiency in line-driven flows

We reexamine the physics of flow driving by line scattering of a continuum radiation source to determine the degree to which such line scattering can heat as well as accelerate the flow. Within the framework of the Sobolev theory for line transfer, we argue that the finite thermal width of the line scattering profile can lead to a significant 'Doppler heating' via photon frequency redistribution within a Sobolev resonance layer. Quantitative computation of this heating shows, however, that it is largely canceled by a corresponding cooling by the diffuse radiation. The resulting reduction in net Doppler heating or cooling means that the overall effect is only of limited importance in the energy balance of line-driven stellar winds. Through simple scaling relations, we compare the effect to other competing heating or cooling terms, including the ion-drag frictional heating recently discussed by Springmann and Pauldrach. We also provide a physical explanation of the unexpected cooling effect, and comment that its near cancellation of the anticipated heating provides another example of the tendency for ideal Sobolev theory to apply to a higher order than expected.
GALACTIC ARCHEOLOGY AND THE HIGH-REDSHIFT DETECTABILITY OF MILKY WAY HALO PROGENITOR GALAXIES

Using a simple model of Milky Way halo formation and chemical evolution, we examine the criteria for observing Milky Way-like progenitor galaxies and the stellar populations within them with the James Webb Space Telescope (JWST). We determine that Milky Way progenitors are visible in deep fields (AB = 30–31) up to z = 7 with low dust content and up to z = 9 with no dust content. These models allow us to determine the fraction of Milky Way halo stars formed in galaxies that should be visible with Near-Infrared Camera on JWST, as a function of metallicity. We show that galaxies in which Galactic halo stars of metallicity above [Fe/H] = −2.5 formed can be detected. Galaxies that form stars with higher metallicities should be visible in deep fields and can be studied by combining observations within the Galaxy as well as external galaxies. We find that halo stars with [Fe/H] <−2.8 formed in progenitor galaxies that are not visible to JWST and that examining their remnants within the Milky Way provides the only realistic prospect of studying these ancient stellar populations. The oldest visible stellar populations are shown to be centrally concentrated, with the stars that formed in visible galaxies at z > 3 residing preferentially within the central 10 kpc region of the Galaxy.
Design of CMOS-APS smart imagers with mixed signal processing and analysis of their transfer characteristics

CMOS imagers based on Active Pixel Sensors (APS) are very important among others because of their possible technical innovations leading to ultra-low power image acquisition or efficient on-chip image preprocessing. Implementation of the image processing tasks (focal plane preprocessing and subsequent image processing) can be done effectively only with the consideration of known transfer characteristics of the imager itself. Geometrical Point Spread Function (PSF) depends on the certain geometric shape of active area in the particular design of CMOS APS. In this paper, the concept of Modulation Transfer Function (MTF) analysis is generalized to be applicable to the sampled structures of CMOS APS. Recalling theoretical results, we have analytically derived the detector MTF in the closed form for some special active area shapes. The paper also deals with the method based on pseudorandom image pattern with uniform power spectral density (PSD). This method allows to evaluate (in contrast to other methods) spatially invariant MTF including sampling MTF. It is generally known that a signal acquired by image sensor contains different types of noises. The superposition of these noises produces noise with a Gaussian distribution. The denoising method based on Bayesian estimator for implementation into the smart imager is presented.
A Note on Simple Gain Score Precision

A distinction is necessary between two concepts of measurement precision. Reliability is population dependent and information is examinee dependent. Both concepts also apply to the simple gain score. Low reliability implies that it is not appropriate to correlate the gain score with variables in a population, and low information implies that no precise statements can be made about an examinee’s true gain. However, low reliability does not imply that statements about within-examinee change are necessarily imprecise.