Sinusoidal velaroidal shell – numerical modelling of the nonlinear buckling resistance

Many works are devoted to linear and nonlinear analyses of shells of classical form. But for thin shells of complex geometry, many things remained to do. Four different sources of nonlinearity exist in solid mechanics. The geometric nonlinearity, the material nonlinearity, the kinetic nonlinearity and the force nonlinearity. The nonlinearity, applied to a sinusoidal velaroidal shell with the inner radius r0, the outer variables radii from 10m to 20m and the number of waves n=8, will give rise to the investigation of its nonlinear buckling resistance. The building material is a high-performant concrete. The investigation emphasizes more on the material and the geometric nonlinearities. The result of the investigation is the buckling force of the shell under self-weight and uniformly vertically distributed load on its area, the corresponding numerical values of displacements and the buckling mode.Keywords: Nonlinear analysis, nonlinear buckling resistance, numerical modelling, sinusoidal velaroidal shell, geometric nonlinearity, material nonlinearity, kinematic nonlinearity, force nonlinearity

Phase shift rule with the optimal parameter selection

The phase shift rules enable the estimation of the derivative of a quantum state with respect to phase parameters, providing valuable insights into the behavior and dynamics of quantum systems. This capability is essential in quantum simulation tasks where understanding the behavior of complex quantum systems is of interest, such as simulating chemical reactions or condensed matter systems. However, parameter shift rules are typically designed for Hamiltonian systems with equidistant eigenvalues. For systems with closely spaced eigenvalues, effective rules have not been established. We provide insights about the optimal design of a parameter shift rule, tailored to various sorts of spectral information that may be available. The proposed method lets derivatives be calculated for any system, regardless of how close the eigenvalues are to each other. It also optimizes the number of phase shifts, which reduces the amount of gate resources needed.Comment: 24 pages, 2 figure

A correlated-polaron electronic propagator: open electronic dynamics beyond the Born-Oppenheimer approximation

In this work we develop a theory of correlated many-electron dynamics dressed by the presence of a finite-temperature harmonic bath. The theory is based on the ab-initio Hamiltonian, and thus well-defined apart from any phenomenological choice of collective basis states or electronic coupling model. The equation-of-motion includes some bath effects non-perturbatively, and can be used to simulate line- shapes beyond the Markovian approximation and open electronic dynamics which are subjects of renewed recent interest. Energy conversion and transport depend critically on the ratio of electron-electron coupling to bath-electron coupling, which is a fitted parameter if a phenomenological basis of many-electron states is used to develop an electronic equation of motion. Since the present work doesn't appeal to any such basis, it avoids this ambiguity. The new theory produces a level of detail beyond the adiabatic Born-Oppenheimer states, but with cost scaling like the Born-Oppenheimer approach. While developing this model we have also applied the time-convolutionless perturbation theory to correlated molecular excitations for the first time. Resonant response properties are given by the formalism without phenomenological parameters. Example propagations with a developmental code are given demonstrating the treatment of electron-correlation in absorption spectra, vibronic structure, and decay in an open system.Comment: 25 pages 7 figure

Green's-function theory of the Heisenberg ferromagnet in a magnetic field

We present a second-order Green's-function theory of the one- and two-dimensional S=1/2 ferromagnet in a magnetic field based on a decoupling of three-spin operator products, where vertex parameters are introduced and determined by exact relations. The transverse and longitudinal spin correlation functions and thermodynamic properties (magnetization, isothermal magnetic susceptibility, specific heat) are calculated self-consistently at arbitrary temperatures and fields. In addition, exact diagonalizations on finite lattices and, in the one-dimensional case, exact calculations by the Bethe-ansatz method for the quantum transfer matrix are performed. A good agreement of the Green's-function theory with the exact data, with recent quantum Monte Carlo results, and with the spin polarization of a $\nu=1$ quantum Hall ferromagnet is obtained. The field dependences of the position and height of the maximum in the temperature dependence of the susceptibility are found to fit well to power laws, which are critically analyzed in relation to the recently discussed behavior in Landau's theory. As revealed by the spin correlation functions and the specific heat at low fields, our theory provides an improved description of magnetic short-range order as compared with the random phase approximation. In one dimension and at very low fields, two maxima in the temperature dependence of the specific heat are found. The Bethe-ansatz data for the field dependences of the position and height of the low-temperature maximum are described by power laws. At higher fields in one and two dimensions, the temperature of the specific heat maximum linearly increases with the field.Comment: 9 pages, 9 figure

Influence of masonry infill walls on longitudinal forces in columns of cast-in-situ framed building

In this paper the result of conducted numerical studies based on space calculation models arepresented. It presents the results of a conducted numerical assessment of the influence ofmasonry infill walls on variation and redistribution of efforts arising in columns of acast-in-situ framed building. The quantitative data of the influence of masonry infill walls onthe redistribution of longitudinal forces in columns of a nine-story of a cast-in-situ framedbuilding are given. It is also shown the particularity of the redistribution of efforts in columnsdepending on their location on the plan and on elevation of a cast-in-situ framed building withmasonry infill walls when designing considering the wind load or the failure of masonry infillwalls of the first-floor.Keywords: cast-in-situ framed building; masonry infill walls; columns; longitudinal forces;variation of forces

THE USE OF BACTERIAL LYSATES IN THE COMPLEX TREATMENT OF PATIENTS WITH CHRONIC DECOMPENSATED TONSILLITIS

Introduction. Chronic tonsillitis (CT) occupies a leading place in the structure of general Oto-rhino-laryngology (ORL) pathology which is characterized by a tendency to an increase in the number of patients with recurrent course, the development of complications and the diversity of etiopathogenetic mechanisms of onset. It has been established that the most acceptable tactic for the prevention of exacerbations of chronic tonsillitis is the use of various groups of drugs that enhance the humoral immunity of the mucous membranes. The drug Ismigen is an immunostimulant based on a bacterial lysate, which increases the body's resistance to infections due to an increase in serum and secretory antibodies, activation of cellular and humoral factors of nonspecific immunity. The aim of the study was to evaluate the effectiveness of the use of Ismigen in the complex treatment of patients with chronic decompensated tonsillitis by studying the dynamics of microbiological indicators. Materials and methods. To achieve this goal, 31 patients with chronic decompensated tonsillitis (CDT) were examined. Patients were divided into 2 groups depending on the proposed treatment regimen: Group A: patients with chronic decompensated tonsillitis who underwent laser tonsillotomy - 15 patients; Group B: patients with chronic decompensated tonsillitis who underwent laser tonsillotomy with further immunostimulation with the drug Ismigen - 16 patients. The control group (CG) consisted of 17 practically healthy individual. Patient in group B had sublingual Ismigen postoperatively: once daily for a period for a period of 10 days. Microbiological examination of the material from the mucous membranes of the tonsils or oropharynx was carried out in dynamics before the treatment, 7 days after the treatment and 1-2 months after the end of the course of treatment. A comprehensive assessment of the status of the oropharynx microbiocenosis was carried out in accordance with the criteria described earlier. According to these criteria, the status of the microbiocenosis of the oropharynx was divided into: eubiosis, dysbiosis of the 1st degree, dysbiosis of the 2nd degree and dysbiosis of the 3rd degree. Results and discussion. Before treatment, in the decompensated state of CT (59.7±2.8) % of the examined subjects was accompanied by dysbiotic manifestations and were classified to grade 3: 60.0% of patients in group A and in 62.5% of patients in group B. In no case pathology of the tonsils did not reveal the microbiological picture of eubiosis. Carrying out various types of therapeutic measures for patients with CDT positively affected the microbiocenosis status of the studied biotope in comparison with the initial data. Comparison of the results of microbiological examination of patients in groups A and B showed the advantages of using immunocorrection after laser tonsillotomy. Thus, in 81.3% of the examined group B microbiocenoses of the mucous membranes of preserved tonsils are represented by eubiosis, compared with 26.7% in group A (p<0.01). The rest of the patients (18.7%) of group B showed dysbiotic phenomena of 1st degree, against 53.3% of persons in group A (p<0.05). The study of the species composition of the oropharynx microbiota of patients with CDT before treatment and its comparison with bacterial antigens that are part of the preparation of Ismigen showed that practically every patient had persistent one or two respiratory pathogens, which are eliminated by bacterial lysates of Ismigen. Immediately after the treatment, there were no significant differences in the incidence of the above-mentioned bacteria between groups of patients. Respiratory pathogens were detected in 5 patients of group A and 3 patients of group B. The density of seeding of the biotope decreased significantly compared to baseline values and averaged lg (4.1±0.2) CFU/g (p <0.01). 1-2 months after the treatment in none of the patients who received the preparation of «Ismigen», the indicated bacteria were detected in the microbiocenosis of the mucous tonsils, against 66.7% of the group A patients who did not undergo sublingual immunization (p<0.01) . «Sanitizing», with respect to the microbial factor of CT, the effectiveness of performed tonsillotomy in a third of patients of group A was lost. The aforementioned respiratory pathogens are most often encountered in chronic inflammatory processes in the upper respiratory tract. Long-term persistence of microorganisms is accompanied by aggravation of immunological disorders and an increased risk of recurrence of the disease [14]. Our studies confirmed the above for patients in Group A, who underwent adequate pathogenetic organ-sparing treatment of the tonsils, but without subsequent immunocorrection. Conclusions. 1. Ismigen, administered to patients with chronic decompensated tonsillitis as part of complex treatment provided a more pronounced antimicrobial effect and promoted restoration of the normocoenosis of the oropharynx. 2. Laser tonsillotomy performed with further immunomodulation with the help of immunostimulant on the basis of bacterial lysates Ismigen, allows to achieve the indices of microbial communities of the mucous membranes of preserved tonsils, which did not differ statistically from the microbiota of the control group of practically healthy persons: in 81.3% of patients, eubiosis and in 18.7% of the dysbiosis of the 1st degree. In persons without pathology of the tonsils, these indicators were 88.2% and 11.8%, respectively. 3. Ismigen has a selective antimicrobial effect against the most common respiratory pathogens, which is objectively manifested by the restoration of the eubiotic colonization profile of the oropharynx in patients with CDT 1-2 months after treatment

Models of nonlinear deformation of concrete in a triaxial stress state and their implementation in the PRINS computational complex

Modern construction standards and regulations prescribe to carry out calculations of concrete and reinforced concrete structures in a nonlinear formulation with account of the real properties of concrete and reinforcement. However, the most of finite-element program complexes cannot perform such calculations in a nonlinear formulation with account of plastic deformations of concrete and reinforcement. To solve this problem, a methodology has been developed and a solid finite element adapted to the PRINS computing complex has been created, which made it possible to perform calculations of reinforced concrete structures considering their actual work. The aim of the study - development and implementation of a method for calculating reinforced concrete structures under conditions of a three-dimensional stress state, considering both brittle fracture and elastic-plastic deformation of concrete. A finite-element methodology, algorithm, and program for calculation of massive reinforced concrete structures with account of plastic deformations of concrete have been presented. The methodology is based on the modified Willam and Warnke strength criterion supplemented with the flow criterion. Two models of volumetric deformation of concrete have been regarded: the elastic model at brittle failure and the ideal elastoplastic model. An eight-node finite element with linear approximating functions of displacements implementing the mentioned deformation models is created. Verification calculations of a massive concrete structure in three-axial compression testify to the accuracy and convergence of the developed finite elements. The PRINS can be effectively used by engineers of designing and scientific organizations to solve a wide class of engineering problems related to calculations of building structures

Probing magnetic and electric optical responses of silicon nanoparticles

We study experimentally both magnetic and electric optically induced resonances of silicon nanoparticles by combining polarization-resolved dark-field spectroscopy and near-field scanning optical microscopy measurements. We reveal that the scattering spectra exhibit strong sensitivity of electric dipole response to the probing beam polarization and attribute the characteristic asymmetry of measured near-field patterns to the excitation of a magnetic dipole mode. The proposed experimental approach can serve as a powerful tool for the study of photonic nanostructures possessing both electric and magnetic optical responses.This work was financially supported by Government of Russian Federation (Project Nos. 14.584.21.0009 10 and GOSZADANIE 2014/190, Zadanie No. 3.561.2014/K, 074- U01), Russian Foundation for Basic Research and the Australian Research Council

Identification of possible non-stationary effects in a new type of vortex furnace

The article presents the results of an experimental study of pressure and velocity pulsations in the model of improved vortex furnace with distributed air supply and vertically oriented nozzles of the secondary blast. Investigation of aerodynamic characteristics of a swirling flow with different regime parameters was conducted in an isothermal laboratory model (in 1:25 scale) of vortex furnace using laser Doppler measuring system and pressure pulsations analyzer. The obtained results have revealed a number of features of the flow structure, and the spectral analysis of pressure and velocity pulsations allows to speak about the absence of large-scale unsteady vortical structures in the studied design