Spin bipolaron in the framework of emery model for high-T(sub c) copper oxide superconductors

The high-T(sub c) oxide compounds discovered recently exhibit a number of interesting physical properties. Two-dimensional antiferromagnetic spin order has been observed in these materials at the oxygen deficiency. This fact can be explained by strong correlation of the spins, situated on Cu sites in the conducting planes of the oxide superconductors. The doping or the oxygen deficiency lead to the occurrence of holes, occupying the oxygen p-orbitals according to the Emery model. At the small hole concentration they can move along the antiferromagnetic lattice of spins, localized on Cu sites. Researchers consider the two holes situation and describe in what way their behavior depends on the antiferromagnetic exchange interation J. It is known that in the framework of Hubbard model with strong on-site Coulomb repulsion, a single hole can form a spin polaron of the large radius. It is reasonable to admit that two holes with parallel spins (triplet) form the spin bipolaron complex owing to the hole excitations' capability to polarize Cu spin surroundings. Such an excitation was considered in the phenomenological way. Here the problem is discussed on the basis of the microscopic approach in the framework of the variational principle. A special kind of wave function is used for such a purpose. The wave function is constructed by generalizing the trial functions proposed in over two holes excitation situation (triplet) and then the region of spin bipolaron existance in the framework of Emery model is studied. In this model the Hamiltonian can be easily rewritten by forming the oxygen states transforming as the irreducible representations of the group D(sub 4)

Firm spin and parity assignments for high-lying, low-spin levels in stable Si isotopes

A natural silicon target was investigated in a natSi(γ, γ′) photon-scattering experiment with fully linearly-polarised, quasi-monochromatic γ rays in the entrance channel. The mean photon energies used were ⟨ Eγ⟩ = 9.33, 9.77, 10.17, 10.55, 10.93, and 11.37 MeV, and the relative energy spread (full width at half maximum) of the incident beam was ΔEγ/ ⟨ Eγ⟩ ≈ 3.5–4 %. The observed angular distributions for the ground-state decay allow firm spin and parity assignments for several levels of the stable even-even silicon isotopes

Lifetime measurements of excited states in ¹⁶³W and the implications for the anomalous B(E2) ratios in transitional nuclei

This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using the recoil-distance Doppler shift method to probe the core polarising effect of the i13/2 neutron orbital on the underlying soft triaxial even-even core. The ratio B(E2:21/2⁺ → 17/2⁺)/B(E2:17/2⁺ → 13/2⁺) is consistent with the predictions of the collective rotational model. The deduced B(E2) values provide insights into the validity of collective model predictions for heavy transitional nuclei and a geometric origin for the anomalous B(E2) ratios observed in nearby even-even nuclei is proposed

Mathematical model of analytical approach of comparative analysis of productivity of agricultural machinery when using visualization technology

Establishment of the effectiveness of organic micronutrient complex on growth and biological mass of juniper juniper (Juniperus sabina L.) seedlings in an enclosed ground UNPK “Agrocenter” was the purpose of the study. The application of organic micronutrient complex increased the current growth of juniper seedlings, root neck diameter, root system length and total height of planting material of juniper. Close interdependence between the growth of juniper seedlings and the dose of fertilizer used is determined by coefficients of determination equal to 0.95-0.98. Accumulation of the biological mass of seedlings, depending on the applied dose, occurs with an increase in the participation of roots and needles by 1.79 and 1.1 times, respectively, in the total biomass of seedlings

Productivity of the forest band system on Chernozeme of the Southern steppe of the Volga Region

The aim of the research was to study the state and productivity of Quercus robur L. when mixed with associated species - Fraxinus lanceolata L. and Acer platanoides L. in the forest band system and in forest bands reinforced with grooves for additional moisture accumulation. The investigations were carried out in the agro-forest landscapes of the steppes of the Volga Upland on the southern chernozem heavy loam with a humus content of 4.5%. In many respects, the productivity of Qvercus robur L. in forest belts depends on the applied mixing scheme, the selection of the accompanying rock, and the timely agrotechnical and silvicultural care in the created forest belts. In recent decades, silvicultural care (harvesting, sanitary, and reforestory cutting) is practically not carried out due to the changed economic situation in forestry and forest melioration in Russia. Therefore, the state and productivity of forest belts with Qvercus robur L. largely depends on the choice of the accompanying tree species that will grow in the forest belt along with Qvercus robur L. Optimal matching schemes for mixing Qvercus robur L. with associated tree species allow for maximum productivity and durability of the forest belt. Studies have shown that when mixing Qvercus robur L. and Acer platanoides L. growth Qvercus robur L. in height and diameter, respectively, by 5% and 14% greater than the growth of Qvercus robur L. when mixed with Fraxinus lanceolata L. Val ditch in the forest band, absorbing additional moisture, contributes to an increase in the intensity of growth of Qvercus robur L. by 10-12%

Productivity of the forest band system on Chernozeme of the Southern steppe of the Volga Region

The aim of the research was to study the state and productivity of Quercus robur L. when mixed with associated species - Fraxinus lanceolata L. and Acer platanoides L. in the forest band system and in forest bands reinforced with grooves for additional moisture accumulation. The investigations were carried out in the agro-forest landscapes of the steppes of the Volga Upland on the southern chernozem heavy loam with a humus content of 4.5%. In many respects, the productivity of Qvercus robur L. in forest belts depends on the applied mixing scheme, the selection of the accompanying rock, and the timely agrotechnical and silvicultural care in the created forest belts. In recent decades, silvicultural care (harvesting, sanitary, and reforestory cutting) is practically not carried out due to the changed economic situation in forestry and forest melioration in Russia. Therefore, the state and productivity of forest belts with Qvercus robur L. largely depends on the choice of the accompanying tree species that will grow in the forest belt along with Qvercus robur L. Optimal matching schemes for mixing Qvercus robur L. with associated tree species allow for maximum productivity and durability of the forest belt. Studies have shown that when mixing Qvercus robur L. and Acer platanoides L. growth Qvercus robur L. in height and diameter, respectively, by 5% and 14% greater than the growth of Qvercus robur L. when mixed with Fraxinus lanceolata L. Val ditch in the forest band, absorbing additional moisture, contributes to an increase in the intensity of growth of Qvercus robur L. by 10-12%

Fire Service of Industrial Enterprises

Cel: Opracowanie nowych naukowo-metodycznych sposobów określenia wielkości sił i środków jednostek straży pożarnej zajmujących się ochroną zakładów przemysłowych, z uwzględnieniem charakterystyki zagrożenia pożarowego przetwarzanych substancji i materiałów, a także technicznych i ekonomicznych parametrów zakładów. Projekt i metody: Ogólna liczba funkcjonariuszy powołanych do ochrony przeciwpożarowej zakładu przemysłowego określana jest poprzez sumę liczby funkcjonariuszy niezbędnych do działań prewencyjnych związanych z działalnością zakładu, liczby funkcjonariuszy pełniących służbę w podziale bojowym, do działań ratowniczo-gaśniczych w obiektach przedsiębiorstwa, a także liczby osób, których zadaniem jest nadzorowanie i zabezpieczanie tych działań. Postawą metodyki do określenia liczebności jednostki niezbędnej do wypełnienia prac prewencyjnych związanych z ochroną przeciwpożarową w zakładzie jest zasada normalizacji czasu poświęconego na wypełnienie konkretnych rodzajów zadań związanych z profilaktyką pożarów. W artykule zostały przedstawione wzory do obliczenia wskaźników korygujących, uwzględniających stopień trudności wykonania następujących prac: i instalacjach w zakładzie, - polegających na kontroli działalności zakładu, obejmujących działania z wykorzystaniem otwartego ognia i prace o podwyższonym zagrożeniu pożarowym, - kontroli pomieszczeń, w których znajdują się węzły kontrolne automatycznych systemów ochrony przeciwpożarowej, - nadzoru nad przestrzeganiem wymogów bezpieczeństwa na terytorium zakładu. Ogólna liczba funkcjonariuszy służby pożarniczej, niezbędna do wypełnienia prac prewencyjnych w przedsiębiorstwie określana jest z uwzględnieniem liczby zmian i obecności osób w firmie na każdej zmianie. Liczbę strażaków, niezbędną do zorganizowania i przeprowadzenia akcji gaśniczej w zakładzie określa się poprzez sumowanie liczby funkcjonariuszy straży pożarnej zatrudnionych do przeprowadzania różnych rodzajów akcji gaśniczych w odniesieniu do wybranego schematu rozwoju pożaru i biorąc pod uwagę wskaźnik rezerwy liczby strażaków, który opracowany jest na założeniu o możliwości zaistnienia niezbędnych zmian personalnych funkcjonariuszy straży pożarnej na czas urlopów, wyjazdów służbowych i zwolnień chorobowych oraz liczby zmian składu personalnego jednostek operacyjnych ochrony przeciwpożarowej zakładu. W artykule omówiono różne rodzaje środków gaśniczych takich jak woda, roztwór wodno-pianowy, proszki gaśnicze. Wyposażenie techniczne jednostek operacyjnych ochrony przeciwpożarowej zakładu określane jest w zależności od ilości środków gaśniczych potrzebnych do ugaszenia modelowanego pożaru. Wyniki: W celu określenia sił i środków niezbędnych do zapewnienia bezpieczeństwa pożarowego przedsiębiorstw przemysłowych opracowane zostały następujące metody: - określenie liczebności służby przeciwpożarowej potrzebnej do organizacji i realizacji zadań z zakresu prewencji pożarowej, - określenie liczebności służby oraz ilości wyposażenia technicznego straży niezbędnych do organizacji i przeprowadzenia akcji gaśniczych, - określenie ogólnej liczebności jednostki ochrony przeciwpożarowej zakładu. Wnioski: Zaproponowane naukowo-metodyczne podejścia pozwoliły opracować projekt zbioru przepisów „Ochrona przeciwpożarowa zakładów przemysłowych. Wymogi ogólne”, który po odpowiedniej procedurze harmonizacji i zatwierdzenia stanie się dokumentem normatywnym w zakresie bezpieczeństwa pożarowego. Dokument będzie stanowił akt do dobrowolnego stosowania w zakresie wymagań dotyczących bezpieczeństwa pożarowego i określi liczebność i normatywne wyposażenie zakładowej jednostki straży powołanej w celu prowadzenia działań profilaktycznych i gaśniczych.Purpose: Excogitation of new scientific and methodological approaches to determine forces and means (firefighters and equipment) of fire service departments needed to provide fire safety in industrial enterprises. New measures should take into account high fire hazard substances and materials used in the enterprises as well as their technical and economic parameters. Project and methods: The total number of firefighters involved in the fire protection of an enterprise is determined by summing the number of firefighters required for the performance of fire-prevention work in the enterprise, the number of firefighters necessary to extinguish fires enterprise premises as well as the number of people which supervise and secure these activities. The aim of this method is to determine the number of fire brigade workers necessary to perform fire-prevention work in the enterprise which is based based on the principle of working time normalization necessary to perform specific types of fire-preventive works. The formulas for calculating adjustment factors take into account the complexity of the following works: - supervision of compliance with fire safety requirements in buildings, premises, warehouses and plants, - measures to control fire-hazardous works including works with the use of open flames in the enterprise, - control of premises where the nodes of the control automatic system of fire protection (ASPZ) are stored, - supervision of compliance with fire safety requirements in the territory of the enterprise. The total number of firefighters required for the performance of fire-prevention work in the enterprise is based on the number of shifts and the presence of workers at each shift. The number of officers in the fire brigade necessary for organization of firefighting action in the enterprise is determined by summing the number of firefighters employed in the different types of firefighting and rescue actions in relation to the chosen scheme of fire development model. What is more, the number depends on the reserve coefficient based on the assumption that there is a necessity of personnel changes in the period of leaves, business travels and sick-leaves and is related to the number of working shifts of the fire service operational division. The following types of extinguishing agents are discussed: water, aqueous foam, powder composition. Technical equipment of the operational fire service divisions protecting the enterprise are determined depending on the required flow rate of the extinguishing agent to extinguish the modelled fire. Results: For determination of forces and means needed to provide fire protection in industrial enterprises the authors developed the following methodology: - determination of the number of firefighters necessary for organization and implementation of fire prevention activities; - determination of the number of firefighters and amount of technical equipment for fire protection of the enterprise for organization and implementation of firefighting actions; - determination of the total number of employees of the fire service. Conclusions: Scientific and methodological approaches proposed by the authors allowed to formulate a draft set of rules “Fire protection of enterprises. General requirements” which after appropriate procedures of endorsement and approval will constitute a normative document on fire safety. The document will be an act of voluntary application and will set fire safety requirements. Moreover, the document will specify the number of firefighters in fire service unit and amount technical equipment needed to protect a company from fires and ensure organization and implementation of fire prevention and / or suppression

COMPARATIVE ANALYSIS OF OPERATIONAL RESPONSE INDICATORS OF FIRE SERVICE UNITS LOCATED IN VARIOUS CLIMATIC CONDITIONS

There was carried out the investigation of operational response indicators (speed of movement, first unit arrival time, coverage rate) of fire service units at settlements of the Krasnodar Region and the Sverdlovsk Region. There were highlighted the cities in which it is necessary to improve fire service activities in order to make the first unit arrival time closer to the normative value