Shock Structure Analysis and Aerodynamics in a Weakly Ionized Gas Flow

The structure of a shock wave propagating through a weakly ionized gas is analyzed using an electrofluid dynamics model composed of classical conservation laws and Gauss Law. A viscosity model is included to correctly model the spatial scale of the shock structure, and quasi-neutrality is not assumed. A detailed analysis of the structure of a shock wave propagating in a weakly ionized gas is presented, together with a discussion of the physics underlying the key features of the shock structure. A model for the flow behind a shock wave propagating through a weakly ionized gas is developed and used to analyze the effect of the ionization on the aerodynamics and performance of a two-dimensional hypersonic lifting body

Domain-Specific Deep Learning Feature Extractor for Diabetic Foot Ulcer Detection

Diabetic Foot Ulcer (DFU) is a condition requiring constant monitoring and evaluations for treatment. DFU patient population is on the rise and will soon outpace the available health resources. Autonomous monitoring and evaluation of DFU wounds is a much-needed area in health care. In this paper, we evaluate and identify the most accurate feature extractor that is the core basis for developing a deep-learning wound detection network. For the evaluation, we used mAP and F1-score on the publicly available DFU2020 dataset. A combination of UNet and EfficientNetb3 feature extractor resulted in the best evaluation among the 14 networks compared. UNet and Efficientnetb3 can be used as the classifier in the development of a comprehensive DFU domain-specific autonomous wound detection pipeline.Comment: 5 pages, 2 figures, 3 tables, 2022 IEEE International Conference on Data Mining Workshop

The e!ects of a non-intervention HACCP implementation on process hygiene indicators on bovine and porcine carcasses

Four sites on each of 720 dressed carcasses (360 bovine and 360 porcine) were sampled (2,880 samples in total) in a single commercial abattoir slaughtering cattle and pigs using two separate slaughterlines. The carcasses were sampled before HACCP (pre-HACCP; 960 samples) and after HACCP implementation (post-HACCP; 1,920 samples) and Total Viable Count (TVC), Enterobacteriaceae count (EC) and Salmonella spp. prevalence were determined. During the pre-HACCP period, mean TVC levels on four tested sites varied on bovine carcasses between 3.03 and 4.19 log10 cfu/cm2 and on porcine carcasses between 3.73 and 3.99 log10 cfu/cm2. During the post-HACCP period, TVC levels on all tested sites on carcasses were further signicantly reduced, by 0.33-1.64 log and 1.13-2.04 log on bovine and porcine carcasses, respectively, compared to the pre-HACCP period. Both the EC occurrence in samples and EC levels in EC-positive samples somewhat decreased during post-HACCP as compared to pre-HACCP period, but the reductions were not statistically signicant due to large proportion of EC-negative samples and very low counts in EC-positive samples. Salmonella spp. was not detected in any of bovine or porcine carcass samples, regardless of whether they were taken pre- or post-HACCP. Overall, the processhygiene- improving eects of non-intervention HACCP have been proven through reduction of TVC on carcasses, but could not be veried in the present study through similar reductions in EC and/or Salmonella, because of their low levels and/or absence

Density‐functional studies of the electronic structure of the perovskite oxides: La1−xCaxMnO3

doi:10.1063/1.361546Using density‐functional methods, we study the electronic structures of the lanthanum‐based ''double‐exchange'' perovskite magnets. Antiferromagnetic insulating solutions are obtained for both the end members, LaMnO3 and CaMnO3, within the local density approximation (LDA), with the Jahn‐Teller (JT) distortion of the oxygen octrahedron taken into account. The JT distortion splits off the Mn(3d)eg bands producing an energy gap within the LDA, with the bands derived from the (z2−1) orbital, pointed along the long basal‐plane Mn—O bond, occupied and the (x2−y2) bands empty. The on‐site Coulomb repulsion and the intra‐site exchange terms are found to be, respectively, U≂8-10 eV and J≂0.9 eV, from the ''constrained'' density‐functional theory. The large value of U as compared to the bandwidth indicates that the manganese perovskite oxides are strongly correlated systems.This work was supported in part by the Office of Naval Research under Contract No. ONR N00014-95-1-0439 and by the Serbian Scientific Foundation under the project, ''Physics of Condensed Matter and New Materials,'' Grant No. 3

Electronic Structure of the Perovskite Oxides: La1-xCaxMnO3

URL:http://link.aps.org/doi/10.1103/PhysRevLett.76.960 DOI:10.1103/PhysRevLett.76.960The electronic structures of the perovskite oxides, LaMnO3 and CaMnO3, are studied using density-functional methods. Antiferromagnetic insulating (AFI) solutions are obtained for both compounds within the local-density approximation (LDA). For LaMnO3 the Jahn-Teller distortion, found necessary for the AFI solution, produces occupied Mn(z2-1) orbitals pointed along the long, basal-plane Mn-O bonds. The large on-site Coulomb U and exchange J, obtained from “constrained” LDA calculations, U≈8-10eV and J≈0.9eV, indicate important correlation effects and yield large redistribution of the spectral weight within the LDA+U approach.We thank O. Gunnarsson for stimulating discussions. This work was supported in part by the Office of Naval Research under Contract No. ONR N00014-95-1-0439

Electronic structure of the substitutional vacancy in graphene: Density-functional and Green's function studies

We study the electronic structure of graphene with a single substitutional vacancy using a combination of the density-functional, tight-binding, and impurity Green's function approaches. Density functional studies are performed with the all-electron spin-polarized linear augmented plane wave (LAPW) method. The three $sp^2 \sigma$ dangling bonds adjacent to the vacancy introduce localized states (V$\sigma$) in the mid-gap region, which split due to the crystal field and a Jahn-Teller distortion, while the $p_z \pi$ states introduce a sharp resonance state (V$\pi$) in the band structure. For a planar structure, symmetry strictly forbids hybridization between the $\sigma$ and the $\pi$ states, so that these bands are clearly identifiable in the calculated band structure. As for the magnetic moment of the vacancy, the Hund's-rule coupling aligns the spins of the four localized V$\sigma_1 \uparrow \downarrow$, V$\sigma_2 \uparrow$, and the V$\pi \uparrow$ electrons resulting in a S=1 state, with a magnetic moment of $2 \mu_B$, which is reduced by about $0.3 \mu_B$ due to the anti-ferromagnetic spin-polarization of the $\pi$ band itinerant states in the vicinity of the vacancy. This results in the net magnetic moment of $1.7 \mu_B$. Using the Lippmann-Schwinger equation, we reproduce the well-known $\sim 1/r$ decay of the localized V$\pi$ wave function with distance and in addition find an interference term coming from the two Dirac points, previously unnoticed in the literature. The long-range nature of the V$\pi$ wave function is a unique feature of the graphene vacancy and we suggest that this may be one of the reasons for the widely varying relaxed structures and magnetic moments reported from the supercell band calculations in the literature.Comment: 24 pages, 15 figures. Accepted for publication in New Journal of Physic

Factorial analysis of slaughter characteristics of fattening pigs fed different additives – Enzyme and probiotic in mixtures

To successfully investigate slaughter characteristics of fattening pigs fed in different ways, this experiment was carried out on Experimental Farm of the Institute for Animal Husbandry, Belgrade- Zemun. Investigation of correlation between slaughter traits of pigs fed with different additives in their nutrition was done by factorial analysis. Slaughter characteristics in three groups of fattening pigs fed in different ways were observed. The first group (variant 1) consisted of fatteners fed diets without any special additives. The second group (variant 2) consisted of pigs fed diets containing enzyme Rovabio, and the third group (variant 3) probiotic Lacture + Microbond. This study was aimed at coming to conclusion based on the results of factorial analysis of the observed traits to the greatest extent which determined slaughter traits of pigs fed diets containing different additives. The results obtained in general, that is, the structure of separated factors showed that different slaughter characteristics are realized with different nutrition.Key words: Fattening pigs, slaughter characteristics, enzyme Rovabio, probiotic Lacture + Microbond, factorial analysis

Bipolar-Driven Large Magnetoresistance in Silicon

Large linear magnetoresistance (MR) in electron-injected p-type silicon at very low magnetic field is observed experimentally at room temperature. The large linear MR is induced in electron-dominated space-charge transport regime, where the magnetic field modulation of electron-to-hole density ratio controls the MR, as indicated by the magnetic field dependence of Hall coefficient in the silicon device. Contrary to the space-charge-induced MR effect in unipolar silicon device, where the large linear MR is inhomogeneity-induced, our results provide a different insight into the mechanism of large linear MR in non-magnetic semiconductors that is not based on the inhomogeneity model. This approach enables homogeneous semiconductors to exhibit large linear MR at low magnetic fields that until now has only been appearing in semiconductors with strong inhomogeneities.Comment: 23 pages, 4 figures (main text), 6 figures (supplemental material

Relativistic calculations of the lifetimes and hyperfine structure constants in 67^{67}Zn+^{+}

This work presents accurate {\it ab initio} determination of the magnetic dipole (M1) and electric quadrupole (E2) hyperfine structure constants for the ground and a few low-lying excited states in $^{67}$Zn$^{+}$, which is one of the interesting systems in fundamental physics. The coupled-cluster (CC) theory within the relativistic framework has been used here in this calculations. Long standing demands for a relativistic and highly correlated calculations like CC can be able to resolve the disagreements among the lifetime estimations reported previously for a few low-lying states of Zn$^{+}$. The role of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented.Comment: 9 pages, 1 figure. submitted to J. Phys. B Fast Trac