Studies of vapor phase synthesis of pyridine bases on non-steady state catalysts

The reaction of NH₃ with R–CHO (R=CH₃, Ph) has been studied. Experimental data and parameters of the laboratory catalytic reactor are reported.

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NH₃ c R–CHO(R=CH₃, Ph). .

     

Ensemble Approach for Detection of Depression Using EEG Features

Depression is a public health issue that severely affects one’s well being and can cause negative social and economic effects to society. To raise awareness of these problems, this research aims at determining whether the long-lasting effects of depression can be determined from electroencephalographic (EEG) signals. The article contains an accuracy comparison for SVM, LDA, NB, kNN, and D3 binary classifiers, which were trained using linear (relative band power, alpha power variability, spectral asymmetry index) and nonlinear (Higuchi fractal dimension, Lempel–Ziv complexity, detrended fluctuation analysis) EEG features. The age- and gender-matched dataset consisted of 10 healthy subjects and 10 subjects diagnosed with depression at some point in their lifetime. Most of the proposed feature selection and classifier combinations achieved accuracy in the range of 80% to 95%, and all the models were evaluated using a 10-fold cross-validation. The results showed that the motioned EEG features used in classifying ongoing depression also work for classifying the long-lasting effects of depression.     

Hydrogenation of 2,3-dihydropyran to tetrahydropyran

The optimum conditions for the hydrogenation of 2,3-dihydropyran to tetrahydropyran on an industrial nickel-chromium catalyst under flow and periodic conditions were found. A regression model for the process was found. The results of hydrogenation of 2,3-dihydropyran by means of a flow reactor and an autoclave of the Vishnevskii type are compared.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 469–472, April, 1982.     

Null geodesies,caustics and apparent motion of galaxies in a finite rotating universe

Null solutions of the geodesic equation are presented for a universe which can be regarded as a rotating and shearing generalization of the static Einstein universe (the Ozsváth class I model). It is shown how the closest caustic, which in the static case just consists of one point at the antipode, grows to form two interwoven closed surfaces when motion is introduced. It is further shown how they prevent causality violating null-like curves. The observed transversal motion of matter (the global rotation) is calculated. The conclusions concerning the causality of the universe which an observer might draw from the global rotation are discussed.     

Ungulate Detection and Species Classification from Camera Trap Images Using RetinaNet and Faster R-CNN

Changes in the ungulate population density in the wild has impacts on both the wildlife and human society. In order to control the ungulate population movement, monitoring systems such as camera trap networks have been implemented in a non-invasive setup. However, such systems produce a large number of images as the output, hence making it very resource consuming to manually detect the animals. In this paper, we present a new dataset of wild ungulates which was collected in Latvia. Moreover, we demonstrate two methods, which use RetinaNet and Faster R-CNN as backbones, respectively, to detect the animals in the images. We discuss the optimization of training and impact of data augmentation on the performance. Finally, we show the result of aforementioned tune networks over the real world data collected in Latvia.     

Some rotating,time-dependent Bianchi type-IX cosmologies with heat flow

It is reported on an investigation of cosmologies which constitute explicit, rotating, and expanding solutions of Einstein's field equations, with spacelike, timelike, or null-like homogeneous hypersurfaces of Bianchi type IX, and the source of which is a non-thermalized perfect fluid.     

Conversion of 1,4-butanediol to furan compounds on cobalt catalysts in the liquid phase

The transformation of 1,4-butanediol on cobalt catalysts applied to kieselguhr in the liquid phase under periodic and continuous conditions was investigated. When the reaction is carried out under periodic conditions, the principal reaction products are 2,3-dihydrofuran, tetrahydrofuran, and -butyrolactone. An increase in the selectivity of the formation of 2,3-dihydrofuran as the temperature is raised was established. 2,3-Dihydrofuran is obtained in 63–73 mole % yields under optimum conditions. 2,3-Dihydrofuran is converted to tetrahydrofuran when the process is carried out under continuous conditions on a tableted cobalt catalyst.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 448–450, April, 1981.     

New hybrid films based on cellulose and hydroxygallium phthalocyanine. Synergetic effects in the structure and properties

Hydroxygallium phthalocyanine (HOGaPc) and cellulose (from a trimethylsilyl derivative) have been used as native elements for the preparation of a novel family of hybrid films. By spin-coating, both components allow the building of films with different configurations on various substrates in a controlled way. The particularities of these hybrid films have been characterized by a range of techniques such as Fourier transform infrared spectroscopy (FTIRS) in attenuated total reflection using multiple internal reflections (ATR/MIR), absorption ultraviolet and visible spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and surface potential measurements using the Kelvin-Zisman vibrating capacitor probe (KP). This enabled determination of the influence of cellulose on the arrangement of HOGaPc and, consequently, control of the relation between the structure and the properties of the films. Finally, gas sensor tests were performed to check the potentialities of these hybrid films. In particular, the synergetic behavior between the film-forming materials allows a fast and sensible change in surface potential after cyclic exposures to ozone (O3, 100 ppb) and nitrogen. Overall, we present the advantages of combining phthalocyanine with cellulose in enhancing the properties of the final product. Introduction of cellulose as a host material opens up a new area of hybrid films.     

Studies of host-guest thin films of corona-poled betaine-type polar molecules by kelvin probe technique and atomic force microscopy

In this work betaine-type molecules were investigated. As a result of the asymmetry of charge distribution, molecules possess in the ground state a considerable permanent dipole moment. The decay of surface potential of poled polymer films is dependent at least on two relaxation processes. The influence of glass transition of PMMA on thermal dependence of the surface potential is shown. The transition temperature, where no changes of the surface potential appeared, is related to glass transition temperature of the host-guest system. The topography of the film surface was obtained by AFM.