Study of the time-differentiated particle flux density at various distances from EAS axis

The EAS time structure is studied using the enlarged EAS array of the Moscow State University. The time measurements are made using 22 scintillators which form 13 rectanges of 180x190 sq m size covering the entire array area. The array is triggered by a signal of 4-fold coincidences of the pulses from the detectors forming each of the rectangles. The data were obtained during 2200 hours of the array operation in 1984. A total of 816 showers, to which at least 14 of 22 scintillator detectors responded, were selected among all those detected. The coordinates of the EAS axis in the observation plane and the EAS sizes were determined by the maximum likelihood method using a computer on the assumption that the electron LDF is the NKG form. A total of 492 showers in the interval of EAS size Ne = 5x10 to the 6th power - 2x10 to the 8th power (N bar e = 1.7x 10 to the 7th power) with zenith angles theta or = 45 deg and axes within the array are analyzed

Double-layer potential of axially symmetric Helmholtz lowest term equation

© 2016,International Journal of Pharmacy and Technology. All rights reserved.1. The classical method for solving boundary value problems is the potential method. Potential kernels are recorded as linear combinations of normal derivatives of the fundamental solutions relating to the corresponding equations. For equations with constant coefficients,the fundamental solutions have,as a rule,a simple form. And as a consequence,it is not difficult to calculate any normal derivatives of them. This topic is described in some university textbooks. Due to numerous applications,the study of equations with singular coefficients is significant in the modern theory of differential equations with partial derivatives. The fundamental solutions are usually recorded as a power series for singular equations; they are limited to the first term in the further studies,and evaluation formulas are used for everything else. Finding a fundamental solution in an explicit form is in itself a significant result. 2. For a singular equation,which is the generalized Helmholtz equation,both with the lowest term and without it,a double-layer potential is found in this work. Potential kernel is a normal derivative of the fundamental solution. In order to find this derivative a special function unit is used. 3. The fundamental solution to the considered equation is expressed in terms of the confluent Horn function. Formula for calculating the normal derivative of this fundamental solution is obtained in the article. The result is written in an explicit form using the same Horn function. Relevance of calculating the normal derivative of the fundamental solution to the axially symmetric Helmholtz equation is determined by its demand in applications and absence of a general theory for this type of equations. 4. When using the formulas associated with the special hypergeometric functions,there was a wide choice to the authors. Using the so-called transformation formula,the result could be recorded in various ways,and not always compactly. The result is recorded in such a way that in calculating the limit values of the potentials the relevant terms will be able to be combined. 5. The potential constructed in this work can be applied to solve any boundary value problems for axially symmetric Helmholtz equation. According to the same scheme,potentials for higher-order equations can be constructed

Spin Crossover [Fe(qsal)2]X (X = Cl, SCN, CF3SO3) Complexes: EPR and DFT Study

The compounds [Fe(qsal)2]X (X = Cl, SCN, CF3SO3) were synthesized and investigated by electron paramagnetic resonance (EPR). The dependence of the Fe(III) spin state on the type of counterion X and on the temperature was established. On the basis of the density functional calculations, the geometrical parameters of compounds in high- and low-spin states were optimized and the difference in their internal energies was calculated. A correlation between the experimental EPR data and the theoretically calculated energy difference between the high-spin and the low-spin states of the compounds with different anions was obtained. © 2010 Springer-Verlag

The current status of orbital experiments for UHECR studies

Two types of orbital detectors of extreme energy cosmic rays are being developed nowadays: (i) TUS and KLYPVE with reflecting optical systems (mirrors) and (ii) JEM-EUSO with high-transmittance Fresnel lenses. They will cover much larger areas than existing ground-based arrays and almost uniformly monitor the celestial sphere. The TUS detector is the pioneering mission developed in SINP MSU in cooperation with several Russian and foreign institutions. It has relatively small field of view (+/-4.5 deg), which corresponds to a ground area of 6.4x10^3 sq.km. The telescope consists of a Fresnel-type mirror-concentrator (~2 sq.m) and a photo receiver (a matrix of 16x16 photomultiplier tubes). It is to be deployed on the Lomonosov satellite, and is currently at the final stage of preflight tests. Recently, SINP MSU began the KLYPVE project to be installed on board of the Russian segment of the ISS. The optical system of this detector contains a larger primary mirror (10 sq.m), which allows decreasing the energy threshold. The total effective field of view will be at least +/-14 degrees to exceed the annual exposure of the existing ground-based experiments. Several configurations of the detector are being currently considered. Finally, JEM-EUSO is a wide field of view (+/-30 deg) detector. The optics is composed of two curved double-sided Fresnel lenses with 2.65 m external diameter, a precision diffractive middle lens and a pupil. The ultraviolet photons are focused onto the focal surface, which consists of nearly 5000 multi-anode photomultipliers. It is developed by a large international collaboration. All three orbital detectors have multi-purpose character due to continuous monitoring of various atmospheric phenomena. The present status of development of the TUS and KLYPVE missions is reported, and a brief comparison of the projects with JEM-EUSO is given.Comment: 18 pages; based on the rapporteur talk given by M.I. Panasyuk at ECRS-2014; v2: a few minor language issues fixed thanks to the editor; to be published in the proceeding

Time-resolved EPR study of radicals from 2,2-dimethoxy-2-phenylacetophenone in ethylene glycol after flash photolysis

The dynamic behaviour of transient free radicals generated by laser pulse photolysis (with λ = 351 nm) of 2,2-dimethoxy-2-phenylacetophenone (DMPA) in ethylene glycol solutions have been studied by time-resolved EPR at room temperature. A main result of the study is a suitable evaluation method for radical systems with CIDEP in the case of very close hyperfine lines and hence with a overlap of several signals. The evaluation of single EPR time-profile signals requires in this case to take in account also the influence of the near resonance positions, what successfully has been done. The formation and decay of the two spin polarized radicals, 7,7-dimethoxy-benzyl (R1) and benzoyl radical (R2), has been observed. For R1 the relaxation time T2 was determined with a good accuracy and the rate constants k1 and k2 were estimated by fitting the time evolution of the EPR signal at resonance and near resonance positions of the field using the Bloch equations and direct Fourier transform analysis. Radicals from DMPA in the high viscous solvent ethylene glycol have been proved to be an excellent model system for this study however the treatment is applicable also for other systems. © 2002 Elsevier Science B.V. All rights reserved

Complexation and ligand exchange in aqueous of Cu(II) and Ni(II) with hydrazides of some aromatic acids

Solvation and complexation of Cu(II) and Ni(II) with benzoic (L′), p-methoxybenzoic (L″), and isonicotinic (L) acid hydrazides in aqueous-ethanol solutions (ethanol mole fraction 0.07-0.68) were studied by pH-metry, spectrophotometry, and nuclear magnetic relaxation. The formation constants of the species M(L′)2+, M(L′) 2 2+ , M(L″)2+, M(L″) 2 2+ , M(LH)3+, M(L)2+, M(L)(LH)3+, and M(L) 2 2+ , where M = Cu2+ and Ni2+, were determined. With isonicotinic acid hydrazide, a change in the coordination mode was observed in an isomer of Cu(L) 2 2+ , with one of the ligands coordinating in the bidentate fashion, and the other, in the monodentate fashion via the pyridine nitrogen atom. The suggested structures were confirmed by analysis of the parameters of the ESR and electronic absorption spectra of the complexes. The rate constants of ligand exchange and formation of the complexes Cu(L′)2+, Cu(L′) 2 2+ , Cu(L″)2+, and Cu(L″) 2 2+ in aqueous solutions were determined from nuclear magnetic relaxation measurements; the reactions occur by the associative mechanism. A cyclic process of reduction of Cu(II) to colloidal copper in the presence of L″ and atmospheric oxygen is described. © Pleiades Publishing, Inc., 2006

Ultrasound-assisted extrusion of construction ceramic samples

© 2017 Elsevier Ltd and Techna Group S.r.l.The conditions for a decrease in friction during ceramic brick production between a mixture and an extruder die under the influence of 20–30 kHz ultrasound applied to the die are calculated. An optimum design of a die used to mold 30 mm diameter cylindrical samples with a resonance in this frequency range is selected using computer modeling. From the results, a titanium die is fabricated and tested on a Verdes–050 (Spain) laboratory extruder using an ultrasonic magnetostrictive transducer with a power of 1.5 kW (Inlab-Ultrazvuk, Russia). A 12% reduction in extrusion pressure, a 20% acceleration of molding and a positive influence on the properties of the ceramics were found. The surface of the ceramic samples was covered by craters with diameters of approximately 10 µm due to the boiling of water, and the porosity of the main body of the samples decreased. This technique prevents the undesirable rapid drying of the surface when the samples exit the die and stabilizes the strength of the fired samples. The color remained unchanged, the water absorption decreased, the density, strength and resistance to frost increased. Ultrasonic extrusion increased the accuracy of the strength tests of construction ceramics, indicating the prospect of ultrasonic die development for industrial extruders for bricks, facing tiles and roof tiles