Miracle-dz/UniFAR-FTUs huggingface dataset:
Flow Pattern and Heat Transfer in a Closed Rotating Annulus

The prediction of the temperature distribution in a gas turbine rotor containing gas-filled closed cavities, for example between two disks, has to account for the heat transfer conditions encountered inside these cavities. In an entirely closed annulus no forced convection is present, but a strong natural convection flow occurs induced by a nonuniform density distribution in the centrifugal force field. A computer code has been developed and applied to a rotating annulus with square cross section as a base case. The co-axial heat flux from one side wall to the other was modeled assuming constant temperature distribution at each wall but at different temperature levels. Additionally the inner and outer walls were assumed to be adiabatic. The code was first verified for the annulus approaching the plane square cavity in the gravitational field, i.e., the ratio of the radius r over the distance h between outer and inner cylindrical wall was set very large. The results obtained agree with De Vahl Davis' benchmark solution. By reducing the inner radius to zero, the results could be compared with Chew's computation of a closed rotating cylinder, and again good agreement was found. Parametric studies were carried out varying the Grashof number Gr,more » the rotational Reynolds number Re, and the r/h ratio, i.e., the curvature of the annulus. A decrease of this ratio at constant Gr and Re number results in a decrease of heat transfer due to the Coriolis forces attenuating the relative gas velocity. The same effect can be obtained by increasing the Re number with the h/r ratio and the Gr number being constant. By inserting radial walls into the cavity the influence of the Coriolis forces is reduced, resulting in an increase of heat transfer. « less
Extraction Of Independent Sources From Correlated Inputs A Solution Based On Cumulants

We propose here a way of extracting independent sources from correlated inputs. The only hypothesis made is that the unknown relations between inputs and sources are linear, but that not more than one source is gaussian. We show the impossibility of extracting sources by only using spectral analysis, and make that extraction possible by using equations which relate inputs and sources, based on the cumulants and cross-cumulants of the inputs.
Prediction of Unsteady Rotor-Surface Pressure and Heat Transfer From Wake Passings

The research described in this paper is a numerical investigation of the effects of unsteady flow of gas turbine heat transfer, particularly of a rotor blade surface. The unsteady flow in a rotor blade passage and the unsteady heat transfer of the blade surface as a result of wake/blade interaction are modeled by the inviscid flow/boundary layer approach. The Euler equations that govern the inviscid flow are solved using a time-accurate marching scheme
Unstable Manifolds of Continuous Self-Mappings

Unstable manifolds of continuous self-mappings on completely densely ordered linear ordered topological spaces (CDOLOTS) are discussed. Let be a continuous self-map. First, the interval with endpoints of two adjacent fixed points is contained in the unilateral unstable manifold of one of the endpoints. Then, by using the above conclusion, we prove that periodic points of not belong to the unstable manifold of their iteration points of (for some ), unless the iteration points are themselves.
Convection-driven planetary dynamos

Abstract Numerical simulations of convection-driven dynamos in rotating spherical shells are employed to better understand the observed strength and geometry of planetary magnetic fields. The model computations cannot be performed for realistic values of several of the control parameters. By varying parameters within the accessible range, it is possible to derive scaling laws for the magnetic field strength and the flow velocity in the dynamo region and for the dipole moment. Our scaling laws suggest that, even though diffusivities are far too large in the models, diffusive processes do not play an important role, just as in planetary cores. Extrapolating the scaling laws to planetary values of the control parameters leads to reasonable predictions for the field strength in the dynamo region and fits the observed dipole moments decently, in particular in the cases of Earth and Jupiter. For Mercury, which does not fit well when applying the scaling laws in a straightforward way, a model is proposed in which the upper part of the fluid core is stably stratified and the dynamo operates only in its deep regions. The time-varying dynamo field must diffuse through the stable region and is attenuated by the skin effect. The model explains why Mercury has a very weak but probably dipole-dominated magnetic field.
Discrete complex images of a three-dimensional dipole above and within a lossy ground

The paper introduces a new method of discrete complex images, to evaluate the Sommerfeld integrals arising in the problem of a three-dimensional dipole above and within a lossy ground. The spectral domain quantity, which is independent of spatial co-ordinates, is accurately approximated by a short series of exponential functions. By use of the Prony method and nonlinear optimisation technique, and through the Sommerfeld equality, the Sommerfeld integrals can be analytically evaluated into simple closed forms of spatial complex images. Various dipoles (HED, VED, HMD and VMD) above and within the lossy ground are studied. Numerical results show that for any parameters of the lossy ground, the closed-form Green function approaches the precision of the ‘nearly exact’ results of Sommerfeld integrals.
Tropical Storm Development from African Easterly Waves in the Eastern Atlantic: A Comparison of Two Successive Waves Using a Regional Model as Part of NASA AMMA 2006

Abstract Two successive African easterly waves (AEWs) from August 2006 are analyzed utilizing observational data, the European Centre for Medium-Range Weather Forecasts reanalysis, and output from the National Center for Atmospheric Research–National Oceanic and Atmospheric Administration Weather Research and Forecasting model (WRF) to understand why the first wave does not develop over the eastern Atlantic while the second wave does. The first AEW eventually forms Hurricane Ernesto over the Caribbean Sea, but genesis does not occur over the eastern Atlantic. The second wave, although weaker than the first over land, leaves the West African coast and quickly intensifies into Tropical Storm Debby west of the Cape Verde islands. This study shows that the environmental conditions associated with the first AEW’s passage inhibited development. These conditions include strong low- and midtropospheric vertical wind shear owing to a stronger than normal African easterly jet, lower than normal relative humidity, a.
Pre-computation of image features for the classification of dynamic properties in breaking waves

ABSTRACT The use of convolutional neural networks (CNNs) in image classification has become the standard method of approaching many computer vision problems. Here we apply pre-trained networks to classify images of non-breaking, plunging and spilling breaking waves. The CNNs are used as basic feature extractors and a classifier is then trained on top of these networks. The dynamic nature of breaking waves is exploited by using image sequences extracted from videos to gain extra information and improve the classification results. We also see improved classification performance by using pre-computed image features such as the Optical Flow (OF) between image pairs to create new models in combination with infra-red images with reduction in errors of up to 60%. The inclusion of this dynamic information improves the classification between breaking wave classes. We also provide corrections to a methodology in the literature from which the data originates to achieve a more accurate assessment of model performance.
On identifiability in the autopsy model of reliability theory

A coherent system is observed until it fails. At the instant of system failure, the set of failed components and the failure time of the system are noted. The failure times of the components are not known. We consider whether the component life distributions can be determined from the distributions of the observed data. Meilijson (1981) gave a condition on the structure of the system that was sufficient for the identifiability of the component distributions, under the assumption that the component life distributions are continuous and have common essential extrema. Nowik (1990) gave necessary and sufficient conditions for identifiability under the more restrictive condition that the component distributions have atoms at their common essential infimum and are mutually absolutely continuous. We give a necessary condition for identifiability, which we show to be equivalent to Nowik's condition, under the assumption that the distributions are continuous and strictly increasing. We derive a sufficient condition for identifiability, more general than Meilijson's, for the case in which the component distributions are assumed to be analytic. We also show that our necessary condition for identifiability is both necessary and sufficient when the component life distributions are assumed to belong to certain parametric families.
On Sommerfeld representation and uniqueness in scattering by wedges

We consider a non‐stationary scattering of plane waves by a wedge. We prove the Sommerfeld‐type representation and uniqueness of solution to the Cauchy problem in appropriate functional spaces developing the general method of complex characteristics (Math. USSR Sb. 1973; 21(1):91–135, Moscow Univ. Math. Bull. 1974; 29(2):140–145, Oper. Theory Adv. Appl. 1992; 57:171–183, Am. Math. Soc. Transl. (2) 2002; 206:125–159). Copyright © 2004 John Wiley & Sons, Ltd.
Criteria for Fragmentation of Rotating Isothermal Clouds. I. Semianalytic Approach

The isothermal collapse of an initially uniform-density, uniform-rotating, molecular cloud core with pressure and self-gravity is investigated using a spheroid model to determine the conditions under which a cloud is unstable to fragmentation. A semianalytic model for the collapse of rotating spheroids is developed with the method of characteristics for inwardly propagating rarefaction waves. It is shown that the criterion for fragmentation is modified from that in the literature if the property of nonhomologous collapse is taken into account. The fate of the collapsing clouds can be divided into three classes: (1) runaway collapsing clouds that approach self-similar solutions with moderate ellipsoid axial ratio (2-5) and are expected to form single adiabatic cores in the center, (2) clouds that collapse and rotationally bounce without fragmentation and are expected to develop bars and filaments, and (3) clouds that collapse into pancakes and fragment during the isothermal stage. We derive the criterion for fragmentation considering the evolution of the flatness of the central core after relaxation in the z-direction. In the small rotation limit, the evolution is determined by only one parameter, α0 (initial ratio of the thermal energy to the gravitational energy), that has the critical value, α0 = 5/π2.
Propagation of Microwaves between a Parallel Pair of Doubly Curved Conducting Surfaces

Microwaves propagated between two doubly‐curved parallel conducting surfaces, in the geometrical optics approximation, follow rays obeying Fermat's principle. The optical distance in this case is determined both by the index of refraction of the material between the surfaces and by the curvature of the surfaces. The focusing properties of such a parallel plate lens is fully specified by giving the metric of the two‐dimensional optical space associated with the mean surface of the guide. A family of equivalent lenses is shown to exist, and formulas are obtained that permit one to go from any one of these lenses to any other. Furthermore, conditions are given for there to exist in a family of equivalent lenses a lens employing a unit index of refraction everywhere. Of particular interest is the demonstration that the Rinehart analog of the Luneberg lens and the RCA ``R‐2R'' lens are members of a two‐parameter family of lenses with analogous focusing properties.
Full-wave analysis of the field distribution of natural modes in the rectangular waveguide grating based on singular integral equation method

The full-wave analysis based on the singular integral equation method is developed to correctly investigate dispersion properties and field distributions inside a rectangular waveguide grating used in low-voltage traveling wave amplifiers. Simplified treatments of periodic structures with rectangular grating are widely used in the analysis of microwave electron beam devices, providing an actually good accuracy for the calculation of dispersion curves of natural modes in a wide range of grating parameters. However, they do not guarantee the correct field distributions in a close proximity to the grating just where an electron beam is usually passed to get more effective beam-wave coupling. The amplitude of the minus-first spatial harmonic, which is mostly responsible for the resonant beam-wave interaction, can be substantially larger than that predicted by the simplified analysis. In addition, the contribution of the higher spatial harmonics to the total field is shown to be significantly larger than that evaluated from the simplified treatment. Consequences of the enhanced influence of higher harmonics on beam-wave interaction are discussed.
Comparative Investigation of Antimicrobial and Antioxidant Effects of the Extracts from the Inflorescences and Leaves of the Cannabis sativa L. cv. strawberry

Cannabis sativa products have historically been used for healing purposes; now their biological properties are supported with scientific evidence, but modern research has not yet fully developed its therapeutic potential. This study focuses on the cultivar of C. sativa called strawberry to understand the biological and medical potentials of hydroalcoholic extracts from two different parts of the plant: leaves and inflorescences. Two biological assets were investigated including antioxidant and antimicrobial potential. Additionally, quantitative determination of phenolic and terpenophenol compounds was conducted. The antimicrobial action was highlighted for the hydroalcoholic extract from inflorescences, especially against Escherichia coli and Bacillus subtilis. Among the dermatophytes’ strains, the most sensitive was Arthroderma currey. These effects could be related albeit partially to the pattern of the phenolics detected, among which the most prominent one was benzoic acid. On the other hand, antioxidant and antimicrobial effects of the extracts could be also mediated by the main terpenophenolics identified and quantified, namely cannabidiolic acid and cannabidiol. Collectively, the present data point to the potential use of the inflorescences from the C. sativa cultivar strawberry as a valuable plant material for the development of bioactive extracts with antioxidant and antimicrobial effects
Assessment of Risk Factors in Pyogenic Liver Abscesses in Children

Background: Pyogenic liver abscess (LA) is a significant contributor to morbidity and mortality in developing countries like India. The risk factors predisposing to the LA specifically in children are not known. Studies done in the past largely remain inconclusive and have identified only probable causes. The cause of LA in children with no coexisting illness remains unknown. Methodology: This prospective observational study was conducted at a tertiary teaching hospital located in New Delhi, India. All children between 2 months and 12 years of age with sonographically confirmed LA presenting to the hospital were included and managed with appropriate intravenous antibiotics and relevant investigations. Results: A total of 52 children were included. The mean age was 6 years and 4 months, and the male: female ratio was 1.4:1. Around 50% of the patients were malnourished. Fever, abdominal pain and loss of appetite were the most common symptoms. Nine patients (17%) were managed conservatively, 13 (25%) needed percutaneous needle aspiration and 30 (57.69%) required drainage using a pigtail catheter. Poor socioeconomic status and anaemia were found to be the most commonly associated risk factors. Selective immunoglobulin A (IgA) deficiency was the most common primary immunodeficiency disorder followed by T-cell defect. On multivariate analysis, it was seen that in those with clinical icterus, gamma-glutamyl transferases >350 IU/m, and those with impending rupture, the time to defervescence was significantly different (P = 0.05). Conclusion: Poor socioeconomic status causing malnutrition emerged as a significant risk factor for LA in children. Selective IgA deficiency was the most common immunodeficiency seen in a few children. Adopting a conservative approach like aspiration and percutaneous drainage led to lower mortality and good recovery rates.
Hydrodynamical instabilities of thermocapillary flow in a half-zone

The stability of the flow in a half-zone configuration is analysed with the aid of direct numerical simulation. The work is concentrated on the small Prandtl numbers relevant for typical semiconductor melts. The axisymmetric thermocapillary flow is found to be unstable to a steady non-axisymmetric state with azimuthal wavenumber 2, for a zone with aspect ratio 1. The critical Reynolds number for this bifurcation is 1960. This three dimensional steady solution loses stability to an oscillatory state at a Reynolds number of 6250. For small Prandtl numbers, both bifurcations are seen to be quite insensitive to changes in the Prandtl number, and are thus hydrodynamic in nature. An analogy to the instability of thin vortex rings is made. This analogy suggests a physical mechanism behind the instability and also gives an explanation of how the azimuthal wavenumber of the bifurcated solution is selected. The implications of this for the floating-zone crystal growth process are discussed.
Design and experimentation of remote driving system for robotic speed sprayer operating in orchard environment

The automation of agricultural machines is an irreversible trend considering the demand for improved productivity and lack of labor in handling agricultural tasks. Unstructured working environments and weather often inhibit a seemingly simple task from being fully autonomously performed. In this context, we propose a remote driving system (RDS) to aid agricultural machines designed to operate autonomously. Particularly, we modify a commercial speed sprayer for orchard environments into a robotic speed sprayer to evaluate the proposed RDS's usability and test three sensor configurations in terms of human performance. Furthermore, we propose a confidence error ellipse‐based task performance measure to evaluate human performance. In addition, we present field experimental results describing how the sensor configurations affect human performance. We find that a combination of a semiautonomous line tracking device and a wide‐angle camera is the most effective for spraying. Finally, we discuss how to improve the proposed RDS in terms of usability and obtain a more accurate measure of human performance.
Portable NIR/MIR Fourier-transform spectrometer based on a common path lamellar grating interferometer

We present a recently developed miniature scanning Fourier-Transform spectrometer (ARCspectro ANIR), which is based on a lamellar grating interferometer and uses a micro-mechanical actuator. The small dimensions of the interferometer (35 mm x 35 mm x 65 mm) and its low weight makes this device a truly portable Fourier-Transform spectrometer. Two different versions of this new spectrometer are presented: one version uses an InGaAs photodiode (0.9μm to 2.6 μm) and the other a MCT detector (2 to 4.5 μm). Their performances are discussed and also illustrated with measurement and application examples.
Ultra-Low Reactive Power Operation and Control Strategy of Hybrid Line Commutated Converter Based on IGCT for HVdc Application

Existing line commutated converter (LCC)-based high-voltage dc (HVdc) systems require large reactive power during operation and reactive power compensation equipment under construction. However, the equipment is expensive and occupies a huge area. In this letter, a novel operation of hybrid line commutated converter based on integrated gate commutated thyristor (IGCT) is proposed to achieve LCC with ultra-low reactive power (LR-LCC), and the corresponding control strategy is developed by utilizing IGCT's active blocking and bidirectional voltage withstanding capability. It can almost eliminate the system's extinguishing angle (γ), and the power factor is close to 1. This novel LR-LCC can result in advantages, including a much lower manufacturing cost and volume of reactive power compensation equipment for HVdc application.
ST-CapsNet: Linking Spatial and Temporal Attention With Capsule Network for P300 Detection Improvement

A brain-computer interface (BCI), which provides an advanced direct human-machine interaction, has gained substantial research interest in the last decade for its great potential in various applications including rehabilitation and communication. Among them, the P300-based BCI speller is a typical application that is capable of identifying the expected stimulated characters. However, the applicability of the P300 speller is hampered for the low recognition rate partially attributed to the complex spatio-temporal characteristics of the EEG signals. Here, we developed a deep-learning analysis framework named ST-CapsNet to overcome the challenges regarding better P300 detection using a capsule network with both spatial and temporal attention modules. Specifically, we first employed spatial and temporal attention modules to obtain refined EEG signals by capturing event-related information. Then the obtained signals were fed into the capsule network for discriminative feature extraction and P300 det- ection. In order to quantitatively assess the performance of the proposed ST-CapsNet, two publicly-available datasets (i.e., Dataset IIb of BCI Competition 2003 and Dataset II of BCI Competition III) were applied. A new metric of averaged symbols under repetitions (ASUR) was adopted to evaluate the cumulative effect of symbol recognition under different repetitions. In comparison with several widely-used methods (i.e., LDA, ERP-CapsNet, CNN, MCNN, SWFP, and MsCNN-TL-ESVM), the proposed ST-CapsNet framework significantly outperformed the state-of-the-art methods in terms of ASUR. More interestingly, the absolute values of the spatial filters learned by ST-CapsNet are higher in the parietal lobe and occipital region, which is consistent with the generation mechanism of P300.
Medical Countermeasures against Ricin Intoxication

Ricin toxin is a disulfide-linked glycoprotein (AB toxin) comprising one enzymatic A chain (RTA) and one cell-binding B chain (RTB) contained in the castor bean, a Ricinus species. Ricin inhibits peptide chain elongation via disruption of the binding between elongation factors and ribosomes, resulting in apoptosis, inflammation, oxidative stress, and DNA damage, in addition to the classically known rRNA damage. Ricin has been used in traditional medicine throughout the world since prehistoric times. Because ricin toxin is highly toxic and can be readily extracted from beans, it could be used as a bioweapon (CDC B-list). Due to its extreme lethality and potential use as a biological weapon, ricin toxin remains a global public health concern requiring specific countermeasures. Currently, no specific treatment for ricin intoxication is available. This review focuses on the drugs under development. In particular, some examples are reviewed to demonstrate the proof of concept of antibody-based therapy. Chemical inhibitors, small proteins, and vaccines can serve as alternatives to antibodies or may be used in combination with antibodies.