Miracle-dz/UniFAR-FTUs huggingface dataset:
Permeability effects of single groin on flow characteristics by JOONGU KANG, HONGKOO YEO, SUNGJUNG KIM and UN JI, J. Hydraulic Res. 49(6), 2011, pp. 728-735

Kang et al. (2011) conducted an experimental study on the flow characteristics around various types of groin structures in an open channel, namely the impermeable rectangular groin, the permeable pile groin, and the triangular-shaped groin. They analysed the relationship between flow features and groin permeability. Their work provides valuable data to understand the flow mechanism near a porous groin and to validate numerical models. The Discussers have developed a 3D numerical model NEWTANK for simulating the flow interaction with porous structures (Liu and Lin 2008, Lin 2008). Their model is based on the Navier–Stokes equations for incompressible fluid flow. It adopts the volume of fluid method to track the free surface motion and employs the porous media method to simulate the impermeable and porous structure. The k−ε model was used to study turbulence transport and dissipation, providing detailed information on the flow velocity, pressure, turbulence, or vorticity both inand outside of porous structures. Figure D1 shows the simulated velocity and vorticity field for case_13 in Table 1 of the original paper. The simulation results were validated against the measured data for Case_1 to Case_15 in the original paper in terms of the flow separation length and width, and the tip velocity at the groin for various groin porosities, resulting in mean relative error of less than 5%. Further, the model is easily extended to other hypothetical cases of different porosity of the groin structures (numerical results 3 in Fig. D2). Using this numerical model, a series of cases with the same conditions as Case_1 to Case_15 (with the approach velocity being between 0.25 m/s to 0.40 m/s were simulated but with different approach flow velocities of 0.2 and 0.5 m/s, resulting Figure D1 3D flow characteristics around groin with 40% permeability
An Algorithm for Generating Multi-Axis NC Machining Tool-Path on Scattered Point Cloud

To achieve the accurate duplication of product in reverse engineering, we proposed an algorithm for generating multi-axis NC machining tool-path directly based on scattered point cloud. At first, we obtained the neighborhoods of tool-path section based on the dynamic spatial index of scattered point cloud and from which we selected the matching points. Then the tool-path section points can be obtained through intersection of the tool-path section and the lines which link the matching points, and the normal vectors of tool-path section points can be calculated based on the differential geometry property of local reference data. Finally we computed the cutter location points by means of projection method and sorted them based on the minimum spanning tree algorithm to form the tool-path. With the results of several experiments, the high precision and efficiency of this algorithm are verified.
Exploring shear yielding and strain localization at the die entry during extrusion of entangled melts

This work applied a particle-tracking velocimetric technique to observe the deformation field in the die entry pressure-driven extrusion, motivated by insights gained from previous studies of entangled melts in simple shear. Based on several styrene-butadiene rubbers and a polybutadiene melt, we show that shear yielding takes place to result in (shear banding-like) strain localization in the die entry. The degree of strain discontinuity is shown to grow with the level of chain entanglement. The critical pressure for shear yielding corresponds to a level of shear stress at a 45° inclined plane that is comparable to the melt plateau modulus, and therefore can be predicted based on our recent understanding of yielding and strain localization in startup shear. The unstable (i.e., time-dependent) shear strain localization in the die entry during continuous extrusion at a sufficiently high volumetric throughput or pressure results in extrudate distortion that is often also known as gross melt fracture.
Dispersion of nonlinear optical susceptibility in GaAs and GaSb

Dispersion measurements of the nonlinear optical susceptibility (NLOS) of GaAs and GaSb crystals are reported. The intensity of the second-harmonic beam generated in the III-V crystal was measured as a function of the frequenvy (1.2-1.8 eV) of the radiation source. This measurement was simultaneously calibrated with respect to the second-harmonic beam generated in a reference quartz crystal. The NLOS modulus was determined from the ratio of the signals in the III-V crystal and the quartz. The dispersion measurements were carried out on mechanically polished crystals. Test measurements on etched crystals, at a few energy values, showed a change in the magnitude of the NLOS, although no significant influence on the spectral shape was found. The structure of the spectra shows good correspondence between the position of the measured peaks and the position of those peaks found in the single-photon (linear) measurements. Previous measurements in GaAs show no such correspondence. Some evidence was found for the possible existence of a two-photon double-resonance transition in GaSb. The Miller-cofficient spectra were calculated. For GaAs the spectrum was found to be approximately constant. For GaSb no pronounced structures were found.
Cross-slot waveguide Bragg grating

A polarization independent band-pass filter is created by combining a silicon cross-slot waveguide and a Bragg grating cavity. By theoretically investigating different types of cavities we show how the sensitivity to polarization of the device can vary, and how we can strongly confine light in a two-dimensional slot waveguide. This kind of structure, where a slot waveguide, a photonic crystal and a nanowire waveguide are merged together, may find applications in the field of sensing. Indeed, a slight variation in the surrounding refractive index breaks the device symmetry. One polarization can thus be used to monitor the fluctuation of the other one. We describe here the principle of a Bragg grating merged with a cross slot waveguide in which a cavity is placed. We discuss the advantage of using different geometries of cavity and how this choice may affect the response of the device.
Numerical analysis on the effects of bandgap energy and polarization of electron blocking layer in near-ultraviolet light-emitting diodes

The influences of bandgap energy and polarization of the electron blocking layer (EBL) in near-ultraviolet light-emitting diodes (NUV LEDs) are systematically investigated. Design curves for the output power of NUV LEDs as a function of bandgap energy and polarization of EBL are provided. The simulation results show that, when the bandgap of the EBL increases, the polarization and polarization-induced charge increase accordingly. Both mechanisms have opposite effects for the EBL in confining electrons. The NUV LEDs with an EBL of large bandgap or small polarization have improved performance due to the enhanced efficiency of electron confining and hole injection.
Coupling between Gravity Waves and Tropical Convection at Mesoscales

AbstractAn idealized cloud-system-resolving model simulation is used to examine the coupling between a tropical cloud population and the mesoscale gravity waves that it generates. Spectral analyses of the cloud and gravity wave fields identify a clear signal of coupling between the clouds and a deep tropospheric gravity wave mode with a vertical wavelength that matches the depth of the convection, which is about two-thirds of the tropospheric depth. This vertical wavelength and the period of the waves, defined by a characteristic convective time scale, means that the horizontal wavelength is constrained through the dispersion relation. Indeed, the wave–convection coupling manifests at the appropriate wavelength, with the emergence of quasi-regular cloud-system spacing of order 100 km. It is shown that cloud systems at this spacing achieve a quasi-resonant state, at least for a few convective life cycles. Such regular spacing is a key component of cloud organization and is likely a contributor to the proce.
Continuous vigilance by echolocating bottlenose dolphins (Tursiops truncatus) for up to fourteen days.

The dolphin’s ability to actively detect randomly presented targets via echolocation for three, continuous, 5‐day sessions and a single 14‐day session was investigated. During each experimental session, a dolphin was required to ensonify the perimeter of its floating enclosure and report the presence of phantom echo generated (PEG) targets by pressing a response paddle. PEG targets were generated by convolving the dolphin’s echolocation signal with the impulse response from a metallic sphere. The resulting PEG target was delayed in time and projected back to the dolphin to simulate the echo of a “real target. ” PEG targets varied in simulated range, location, and time of occurrence. Percent correct for target detection were 97, 99, and 100 for dolphin A and 75, 78, and 86 for dolphin B, during each 5‐day session, respectively. During a 14‐day session, dolphin A reported 98% of the targets correctly. False alarm rates were low and there was no significant effect of range or inter‐trial‐interval on percent correct or response time. The results indicate that dolphins are capable of continuously monitoring their environment via echolocation for multiple days (at least 14 days) and can accurately report the presence of regularly occurring targets.
The inviscid nonlinear instability of parallel shear flows

In this paper we assume the existence of a nonlinear boundary layer centred on the critical point, and explore its effect on the development of unstable parallel shear flows. A velocity matching condition derived in a qualitative discussion suggests a growth of harmonics which differs from that predicted by previous theories; however, the prediction is in excellent agreement with experimental data. A hyperbolic-tangent velocity profile, subjected to perturbations with wavenumbers and frequencies close to marginal values, is then chosen as a mathematical model of the nonlinear development, both temporal and spatial instability growth being considered. A singularity in the analysis which has been treated in previous theories by the introduction of viscosity is dealt with in the present work by the introduction of a growth boundary layer. The asymptotics are non-uniform and the time-dependent solution does not resemble the steady viscous solutions, even as the growth rate tends to zero. The theory suggests that the instability will develop as a series of temporally growing spiral vortices, a description differing from that of a cat's-eye pattern predicted by existing theories, but in accord with experimental and field observations.
Line segment matching based on the depth face of building

The paper presents an algorithm to find homonymous line segments from images based on the depth face of building. TIN is formed from the object points calculated by homonymous points in stereopair, and contour lines are inserted from TIN with a given interval. With image and contour lines, the different depth faces of building can be partitioned approximately. Homonymous line segments are found in different depth faces by matching along epipolar line, the method is tested feasible. It solves the problem of line matching in the changed area of building depth face simultaneously.
Infrared radiation from dark globules

Theoretical models are constructed by which to study the infrared emission from dark globules heated by the interstellar radiation field (ISRF). The effects of cloud parameters (grain type, optical depth, and density inhomogeneity) on the emergent spectrum and infrared surface brightnesses are studied. Compared with clouds which have internal heat sources, the emergent flux for globules is found to be at least a factor of 10 smaller and to peak at wavelengths 100 . mu.m< or =lambda< or =130 . mu.m for graphite clouds and 310 . mu.m< or =lambda< or =550 . mu.m for silicate clouds. Either limb brightening or limb darkening in the infrared can occur, which depends sensitively on the optical depth. For globules of moderate extinction (greater than approx.10 in the visible), significant infrared limb brightening occurs at wavelengths of grain emission (20 .mu.m< or =lambda< or =600 .mu.m). A physical interpretation of these results is presented. To help remove ambiguities from interpretations of future observations, the observable effects of a grain mixture, variation of the ISRF, as well as beam dilution are examined in detail. The presence of a second grain component alters the emergent spectrum significantly. For a variation of the ISRF within wide limits, the ratio ofmore » surface to central temperature (T/sub s//T/sub c/) of an optically thick cloud remains fairly constant (3< or approx. =T/sub s//T/sub c/< or approx. =4). Infrared limb brightening may be smoothed out by beam dilution as well as by density inhomogeneities. Finally, the expected flux densities in the infrared of a typical globule are presented for different beam sizes. The predicted fluxes are within the detection threshold of currently available infrared detectors, using either ground-based or balloon-borne telescopes. « less
Maximum likelihood estimation using the empirical fisher information matrix

In this paper the use of the empirical Fisher information matrix as an estimator of the information matrix is considered in the context of response models and incomplete data problems. The introduction of an additional stochastic component into such models is shown to greatly increase the range of situations in which the estimator can be employed. In particular the conditions for its use in incomplete data problems are shown to be the same as those needed to justify the use of the EM algorithm.
Enhancement of ultraviolet emissions from ZnO films by Ag doping

The Ag-doped ZnO films were deposited on Si substrates by dc reactive sputtering. Obvious enhancement of ultraviolet (UV) emission of the samples was observed due to Ag2O nanoclusters formatted during Ag doping. The UV emission consisted of two peaks. The 348nm peak was attributed to Ag2O nanoclusters, and the 382nm one was attributed to ZnO. The strongest UV emission of a certain ZnO–Ag2O film was over ten times stronger than that of a pure ZnO film, which was an exciting result. The enhancement of UV emission was caused by excitons formed at the interface between Ag2O nanoclusters and ZnO grains.
Bioecological Study on the Sand Flies (Diptera: Psychodidae, Phlebotominae) in Sari County, North of Iran

Background: Phlebotomine sand flies are vectors of Leishmania species, the causative agents of leishmaniasis in the world. Present study aimed to evaluate the bioecological aspects of sand flies in different ecotopes in Sari County, north of Iran. Methods: Sand flies were collected from four villages in mountainous, forest, plain and peri-urban areas monthly using sticky traps in May–October 2016. Mounted specimens were identified using valid identification keys under optical microscope. The Arc GIS 10.5 software was applied for showing the distribution of sand flies. Shannon-Weiner, Simpson and Evenness species diversity indices were calculated. Results: Generally, 334 specimens were captured and identified, namelly Phlebotomus kandelakii, Ph. papatasi, Ph. major, Ph. sergenti, Ph. longiductus, Ph. halepensis, Ph. tobbi, Sergentomyia dentata, Se. theodori, Se. sintoni, Se. antennata and Se. sumbarica. The most common species was Ph. kandelakii (n= 128, 38.32 %). The highest Simpson index (0.81) and abundance (N= 141) were recorded in the mountaineous area. Shannon diversity index was higher in the forest (H'= 1.53) and the highest evenness index was in the plain area (J'= 0.93). The highest richness (S= 9) and Shannon indices (H'= 1.57) were observed in June. Conclusions: Phlebotomus kandelakii, Ph. sergenti, Ph. tobbi, Ph. longiductus, Se. theodori, Se. antennata and Se. sumbarica were recorded for the first time in the study area. Since some species are incriminated for leishmaniasis transmission, further studies are required in the northern regions of Iran to timely control measures planning.
Extreme ultraviolet composite spectra of representative solar features

The spectral identifications and absolute intensities of lines in the EUV spectrum for various solar features, such as the quiet sun, active regions, coronal holes, and the off-limb corona, are presented and discussed. Composite spectra have been assembled and processed from the ATM ultraviolet spectrometer data with a spectral resolution of 1.6 A over the range 280-1350 A. These spectra represent a self-consistent set of observations with good photometric calibration, in which intercomparison of intensities from different regions is used to assist in line identifications and to draw general conclusions on average physical conditions in the solar atmosphere. The quiet-sun line intensities obtained near solar minimum are compared with OSO 6 results near solar maximum to provide an estimate for the changes over the solar cycle.
Quasispherical subsonic accretion in X-ray pulsars

A theoretical model is considered for quasispherical subsonic accretion onto slowly rotating magnetized neutron stars. In this regime, the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasistatic shell. Angular momentum transfer in the shell occurs via large-scale convective motions resulting, for observed pulsars, in an almost iso-angular-momentum rotation law inside the shell. The accretion rate through the shell is determined by the ability of the plasma to enter the magnetosphere due to Rayleigh–Taylor instabilities, with allowance for cooling. A settling accretion regime is possible for moderate accretion rates . At higher accretion rates, a free-fall gap above the neutron star magnetosphere appears due to rapid Compton cooling, and the accretion becomes highly nonstationary. Observations of spin-up/spin-down rates of quasispherically wind accreting equilibrium X-ray pulsars with known orbital periods (e.g., and ) enable us to determine the main dimensionless parameters of the model, as well as to estimate surface magnetic field of the neutron star. For equilibrium pulsars, the independent measurements of the neutron star magnetic field allow for an estimate of the stellar wind velocity of the optical companion without using complicated spectroscopic measurements. For nonequilibrium pulsars, a maximum value is shown to exist for the spin-down rate of the accreting neutron star. From observations of the spin-down rate and the X-ray luminosity in such pulsars (e.g., , and ), a lower limit can be put on the neutron star magnetic field, which in all cases turns out to be close to the standard value and which agrees with cyclotron line measurements. Furthermore, both explains the spin-up/spin-down of the pulsar frequency on large time-scales and also accounts for the irregular short-term frequency fluctuations, which may correlate or anticorrelate with the observed X-ray luminosity fluctuations.
Spectral-spatial classification of hyperspectral images with k-means++ partitional clustering

We propose and investigate a complex hyperspectral image classification method with regard to the spatial proximity of pixels. Key feature of the method is that it uses common and relatively simple algorithms to attain high accuracy. The method combines the results of pixel-wise support vector machine classification and a set of contours derived from kmeans++ image clustering. To prevent redundant processing of similar data a principal component analysis is used. The method proposed enables the accuracy and speed of hyperspectral image classification to be enhanced.
Photo forgery detection using RGB color model permutations

ABSTRACT A detection of fake photos is a serious concern since general users can easily create with mobile apps and computer software. In this paper, a novel method that can detect fake photos accurately is proposed. RGB color model permutations are considered and non-decimated shift-invariant wavelet transform is applied. The proposed method extracts features using the Markov process and texture operator based on co-occurrence in both the spatial and frequency domains. The feature vector dimension is reduced by using an infinite feature selection algorithm and feature selection provides quality features to improve a detection accuracy and reduce a classification model training time. The experimental analysis is performed on four photo forgery datasets and demonstrated the accuracy of the proposed scheme is outstanding for both types of forgery, splicing and copy-move when compared with previous forgery detection schemes.
Helmet-Mounted Real-Time Toxic Gas Monitoring and Prevention System for Workers in Confined Places

Occupational health and safety hazards associated with confined places are mainly caused by exposure to toxic gases and oxygen deficiency. Lack of awareness, inappropriate monitoring, and improper evacuation methods can lead to worker fatalities. Although previous studies have attempted to develop systems to solve this issue, limited research is available on their application in confined places. In this study, a real-time helmet-mounted system was developed to monitor major toxic gases (methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon monoxide (CO)), oxygen, temperature, and humidity. Workers outside and inside confined spaces receive alerts every second to immediately initiate the rescue operation in the event of a hazard. The test results of a confined environment (wastewater treatment unit) highlighted that concentrations of CH4 and H2S were predominant (13 ppm). Compared to normal atmosphere, CH4 concentration was 122- and 130-fold higher in the landfill and digestion tanks, respectively, while H2S was 36- and 19-fold higher in the primary and secondary clarifiers, respectively. The oxygen content (18.2%) and humidity (33%) were below the minimum required limits. This study will benefit future research to target appropriate toxic gas monitoring and alert workers by studying the existing issues and associated factors in confined places.
Human dimensions of grizzly bear conservation: The social factors underlying satisfaction and coexistence beliefs in Montana, USA

Coexistence between large carnivores and humans is a global conservation concern. Montana (USA) is home to recovering grizzly bear (Ursus arctos) populations and increasing human–grizzly interactions. In 2019, we administered a survey of Montanans to investigate factors influencing normative beliefs about grizzly bear population sizes and quantify the relationship between these beliefs and satisfaction with grizzly management in the state. Using a linear regression (r2 = .61), we found that residents with positive attitudes and emotional dispositions toward grizzlies or who trusted the agency were more likely to believe grizzly populations were too low. Residents who believed hunting should be used to manage conflict, were themselves hunters, had vicarious wildlife experience with property damage, believed grizzly populations were expanding, or were older were more likely to believe populations were too high. We found a negative quadratic relationship between normative grizzly bear population size beliefs and satisfaction with management, suggesting an optimal “Goldilocks” zone where coexistence is most possible. In practice, if observed Goldilocks zones are incompatible with population numbers required to meet conservation goals, considering factors influencing these beliefs may help bolster acceptance of larger population sizes.