Optimum Shape Design Using Automatic Differentiation in Reverse Mode

This paper shows how to use automatic differentiation in reverse mode as a powerful tool in optimization procedures. It is also shown that for aerodynamic applications the gradients have to be as accurate as possible. In particular, the effect of having the exact gradient of he first or second order spatial discretization schemes is presented. We show that the loss of precision in the gradient affects not only the convergence, but also the final shape. Both two and three dimensional configurations of transonic and supersonic flows have been investigated. These cases involve up to several thousand control parameters

A simplified approach to the magnetic blue shift of Mott gaps

The antiferromagnetic ordering in Mott insulators upon lowering the temperature is accompanied by a transfer of the single-particle spectral weight to lower energies and a shift of the Mott gap to higher energies (magnetic blue shift, MBS). The MBS is governed by the double exchange and the exchange mechanisms. Both mechanisms enhance the MBS upon increasing the number of orbitals. We provide an expansion for the MBS in terms of hopping and exchange coupling of a prototype Hubbard-Kondo-Heisenberg model and discuss how the results can be generalized for application to realistic Mott or charge-transfer insulator materials. This allows estimating the MBS of the charge gap in real materials in an extremely simple way avoiding extensive theoretical calculations. The approach is exemplarily applied to $\alpha$-MnTe, NiO, and BiFeO$_3$ and an MBS of about $130$ meV, $360$ meV, and $157$ meV is found, respectively. The values are compared with the previous theoretical calculations and the available experimental data. Our ready-to-use formula for the MBS simplifies the future studies searching for materials with a strong coupling between the antiferromagnetic ordering and the charge excitations, which is paramount to realize a coupled spin-charge coherent dynamics at a femtosecond time scale.Comment: 16 pages, 13 figure

From Gapped Excitons to Gapless Triplons in One Dimension

Often, exotic phases appear in the phase diagrams between conventional phases. Their elementary excitations are of particular interest. Here, we consider the example of the ionic Hubbard model in one dimension. This model is a band insulator (BI) for weak interaction and a Mott insulator (MI) for strong interaction. Inbetween, a spontaneously dimerized insulator (SDI) occurs which is governed by energetically low-lying charge and spin degrees of freedom. Applying a systematically controlled version of the continuous unitary transformations (CUTs) we are able to determine the dispersions of the elementary charge and spin excitations and of their most relevant bound states on equal footing. The key idea is to start from an externally dimerized system using the relative weak interdimer coupling as small expansion parameter which finally is set to unity to recover the original model.Comment: 18 pages, 10 figure

The Behaviour of Swine

The pig was a forest-dwelling animal from the beginning of its history. In some parts of the world it has been domesticated for at least 7000 years. The European breeds of domestic swine were derived from the local wild pig, Sus scrofa. Herds ranged in pastures and forests and kept indoors only for fattening. The breeds in the Far East were derived from another wild pig, Sus vittatus, a smaller animal with shorter legs and a higher reproductive ability (Mohr 1960; Zeuner 1963). The two types interbred readily. The modem breeds of pig evolved from different crossings between the two original types. They form a rich diversity of genetic material and more than 200 breeds have been catalogued. Certain wild types of pig-like animals, such as the African bush pig (Pontamochoerus larvatus) and the wart hog (Phacochoerus aethiopecus), have never been domesticated. The basis of the social structure in feral swine is the matriarchal herd: one or several females with their offspring. The males are not permanently associated to such herds, often ranging solitary or in \u27bachelor\u27 groups (Fig. 52). Under domestication the pig has been modified from a pugnacious, free-ranging, foraging beast to a more docile animal which is handled readily in large groups under conditions of confined rearing. The behavioural plasticity of swine is emphasized by the rapidity with which wild pigs have adapted to rearing in restricted conditions. Although most of our knowledge of the behaviour of swine has been gained from data collected incidentally to research on nutrition, breeding, physiology and management, a number of experimental studies have recently appeared in learning, adaptation, social, sexual and maternal behaviours, making the pig the best known species among domestic mammals, from the point of view of behaviour

Simple approach to thieno[3,2-d]pyrimidines as new scaffolds of antimicrobial activities

6-(4-Chlorophenyl)-spiro[cyclohexane-1,2-thieno[3,2-d][1,3]oxazin]-4(1H)-one (1) was synthesized and used as a starting material for the synthesis of a novel series of spiro compounds having biologically active sulfonamide (2a-e) and 3-(4-acetylphenyl)-6-(4-chlorophenyl)-1H-spiro[cyclohexane-1,2-thieno[3,2-d]pyrimidine-4(3H)-one (3). Compound 2a was used as a key intermediate for the synthesis of sulfonyl carbothioamide derivatives (4a-c). Also, compound 3 was used as an intermediate for the synthesis of 3H-spiro[cyclohexane-1,2-thieno[3,2-d]pyrimidin]-3-yl]phenyl}-2-imino-4-(substituted phenyl and/or thienyl)-1,2-dihydropyridine-3-carbonitrile derivatives (5a-e), 3H-spiro[cyclohexane-1,2-thieno[3,2-d]pyrimidin]-3-yl]phenyl}-2-oxo-4-(substituted phenyl and/or thienyl)-1,2-dihydropyridine-3-carbonitrile derivatives (6a-e), and 4-[(2Z)-3-substituted-arylprop-2-enoyl]phenyl-1H-spiro[cyclohexane-1,2-thieno[3,2-d]pyrimidine derivatives (7a-e). Cyclocondensation of 7a-e with hydrazine hydrate produced 6-(4-chlorophenyl)-3-[4-(5-substituted aryl-4,5-dihydro-1H-pyrazol-3-yl)phenyl]-1H-spiro[cyclohexane-1,2-thieno-[3,2-d]pyrimidin]-4(3H)-ones (8a-e), but with hydroxylamine hydrochloride afforded the corresponding isoxazoline derivatives (9a-e). Also, cyclocondensation by thiourea afforded 2-thioxo-1,2-dihydropyrimidin-4-yl)-phenyl-spiro-{cyclohexanethieno[3,2-d]pyrimidin}-4-one derivatives (10a-e). The new compounds were investigated for antimicrobial activity. Compounds 2c, 8b, c, 9b and 10b were the most potent ones against both Gram-negative and Gram-positive bacteria. Compound 8c exhibited higher antifungal activity towards the examined fungi with MIC of 1–2 µmol mL–1 compared to ketoconazole (MIC 2–3 µmol mL–1)

A high-finesse Fabry-Perot cavity with a frequency-doubled green laser for precision Compton polarimetry at Jefferson Lab

A high-finesse Fabry-Perot cavity with a frequency-doubled continuous wave green laser (532~nm) has been built and installed in Hall A of Jefferson Lab for high precision Compton polarimetry. The infrared (1064~nm) beam from a ytterbium-doped fiber amplifier seeded by a Nd:YAG nonplanar ring oscillator laser is frequency doubled in a single-pass periodically poled MgO:LiNbO$_{3}$ crystal. The maximum achieved green power at 5 W IR pump power is 1.74 W with a total conversion efficiency of 34.8\%. The green beam is injected into the optical resonant cavity and enhanced up to 3.7~kW with a corresponding enhancement of 3800. The polarization transfer function has been measured in order to determine the intra-cavity circular laser polarization within a measurement uncertainty of 0.7\%. The PREx experiment at Jefferson Lab used this system for the first time and achieved 1.0\% precision in polarization measurements of an electron beam with energy and current of 1.0~GeV and 50~$\mu$A.Comment: 20 pages, 22 figures, revised version of arXiv:1601.00251v1, submitted to NIM

Interpretation of multispectral and infrared thermal surveys of the Suez Canal Zone, Egypt

Remote sensing airborne surveys were conducted, as part of the plan of rehabilitation, of the Suez Canal Zone using I2S multispectral camera and Bendix LN-3 infrared passive scanner. The multispectral camera gives four separate photographs for the same scene in the blue, green, red, and near infrared bands. The scanner was operated in the microwave bands of 8 to 14 microns and the thermal surveying was carried out both at night and in the day time. The surveys, coupled with intensive ground investigations, were utilized in the construction of new geological, structural lineation and drainage maps for the Suez Canal Zone on a scale of approximately 1:20,000, which are superior to the maps made by normal aerial photography. A considerable number of anomalies belonging to various types were revealed through the interpretation of the executed multispectral and infrared thermal surveys