FREQUENCY DETERMINATION OF PULSE SIGNAL WITH CONSTANT BEAT BY DINT OF RECURRENT USAGE OF FOURIER TRANSFORM

The paper proposes an algorithm for frequency estimation of a pulse signal with constant beat under significant distortion conditions with the use of spectral analysis methods. The sequential processing of the signal based on the recurrent usage of discrete Fourier transform is shown. The initial pulse signal is represented as a fragment of the Dirac comb. Its Fourier spectrum also contains a fragment of the Dirac comb. To reduce the effect of leakage due to the application of Fourier transform to the finite sequence, a convolution of the signal with a weight window is used. To increase the signal-to-noise ratio and reduce the side lobe level, the spectrum of the initial signal is taken as the original for Fourier transform with an increased number of spectral lines. The necessity of recurrent transformation usage is brought about by the noise of the initial signal and the resulting spectrum after the first application of Fourier transform. In comparison with a single application of the transformation, this approach provides an opportunity to recognize a useful signal both against the background of Gaussian and aperiodic impulse noise, and against the background of signals containing such noise in the Fourier spectrum. We give a method for checking the local maxima of the amplitudes of the obtained discrete Fourier transform for periodicity. The frequency of a pulse signal with constant beat is determined by the element index with the largest number of fulfillment of the periodicity condition

SOLUTION OF SIGNAL UNCERTAINTY PROBLEM AT ANALYTICAL DESIGN OF CONSECUTIVE COMPENSATOR IN PIEZO ACTUATOR CONTROL

Subject of Research.We present research results for the signal uncertainty problem that naturally arises for the developers of servomechanisms, including analytical design of serial compensators, delivering the required quality indexes for servomechanisms. Method. The problem was solved with the use of Besekerskiy engineering approach, formulated in 1958. This gave the possibility to reduce requirements for input signal composition of servomechanisms by using only two of their quantitative characteristics, such as maximum speed and acceleration. Information about input signal maximum speed and acceleration allows entering into consideration the equivalent harmonic input signal with calculated amplitude and frequency. In combination with requirements for maximum tracking error, the amplitude and frequency of the equivalent harmonic effects make it possible to estimate analytically the value of the amplitude characteristics of the system by error and then convert it to amplitude characteristic of open-loop system transfer function. While previously Besekerskiy approach was mainly used in relation to the apparatus of logarithmic characteristics, we use this approach for analytical synthesis of consecutive compensators. Main Results. Proposed technique is used to create analytical representation of "input–output" and "error–output" polynomial dynamic models of the designed system. In turn, the desired model of the designed system in the "error–output" form of analytical representation of transfer functions is the basis for the design of consecutive compensator, that delivers the desired placement of state matrix eigenvalues and, consequently, the necessary set of dynamic indexes for the designed system. The given procedure of consecutive compensator analytical design on the basis of Besekerskiy engineering approach under conditions of signal uncertainty is illustrated by an example. Practical Relevance. The obtained theoretical results are used in the task of developing precise positioning systems with piezoelectric actuation mechanism. Proposed procedure for analytical synthesis of consecutive compensator is also believed to be usable for design of servo mechanisms of arbitrary application

Detection technique of the optical and thermoradiative characteristics with compensation effect of reflection and transmittance indicatrices for the semitransparent materials with high subsurface scattering

The experimental set-up is developed for detection of reflection and transparence coefficients of semitransparent materials within visible and IR radiation diapasons. The peculiarity of the set-up is using the spectral photometric integrating spheres for effect compensation of reflection indicatrices of tested materials with fixed wavelengths 0.63 μm 1.15 μm (near IR), 2.79 μm and 3.39 μm (middle infrared) of probing laser radiation. In the first case the integrating sphere is a photometric ball which made from porous fluoroplastic with high reflectivity up to 97-99%. For the second range an aluminum sphere (sand blasting) was used. The application of the photometric sphere reduced the measurement error, connected with different sensitivity of photosensors to beam slope angle of detected radiation reflected (transmitted) for flat material samples with different indicatrices of reflection (transmission). The proposed method of experimental measurements of spectral photometric characteristics of reflection and transparent improve the accuracy of theoretical estimations of the optical (thermoradiation) parameters (absorption and scattering indexes), as well as the functions of a thermal radiation heat source for the calculation of temperature fields in semitransparent materials. For the first time, a computational and experimental estimation of scattering and absorption indexes (with an accuracy not less than 1%) were carried out for semitransparent materials with high scattering (porous ceramics based on stabilized zirconium dioxide) in the middle infrared range of wavelengths which is most problematic for optical measurements. © 2019 IOP Publishing Ltd. All rights reserved

ОРГАНИЗАЦИЯ КОРРЕКТНОГО ЛЕЧЕНИЯ БОЛЬНЫХ С ПЕРЕЛОМАМИ ПРОКСИМАЛЬНОГО ОТДЕЛА БЕДРЕННОЙ КОСТИ

A retrospective analysis of the quality of specialized care provided to 820 patients with proximal femur fractures (PFF) at Solovyov Hospital (Yaroslavl) in 2013 was performed. A direct relationship was established between the time elapsed from the injury to hospital admission and the rate of vein thrombosis of the lower limbs. Operative activity in the treatment of patients with this pathology was 91.7%. A need for different implants for operative treatment of patients with this injury per 100,000 population was determined. Operative treatment of PFF in elderly and old-aged people should be considered a life-saving procedure to be performed on urgent indications(within 24 to 48 hours since the injury).Проведен ретроспективный анализ качества оказания специализированной помощи 820 больным с переломами проксимального отдела бедренной кости (ППБОК) в больнице им. Н.В. Соловьева (г. Ярославль) в 2013 г. Установлена прямая зависимость между сроком, прошедшим от травмы до госпитализации больных в стационар, и частотой развития тромбозов вен нижних конечностей. Отмечена высокая операционная активность (91,7%) в лечении пациентов. Определена потребность в различных имплантатах для оперативного лечения больных с указанными травмами при расчёте на 100 тысяч населения. Оперативное лечение ППОБК у лиц пожилого и старческого возраста следует рассматривать как жизнеспасающую процедуру и выполнять по срочным показаниям (в течение 24-48 часов с момента получения травмы)

Ultimate Venous Hemostasis Method

Porous nitinol plate germinated by nerve, connective tissue cells and capillaries is biomechanically and biophysically compatible with vein based on study above. It becomes a mechanical carcass to form a blood vessel wall in defect area, so designed technic provides fast and safe hemostasis with bloodstream recovery

Ultimate Venous Hemostasis Method

Porous nitinol plate germinated by nerve, connective tissue cells and capillaries is biomechanically and biophysically compatible with vein based on study above. It becomes a mechanical carcass to form a blood vessel wall in defect area, so designed technic provides fast and safe hemostasis with bloodstream recovery

Clinical assessment of xenograft combined with knitted TiNi-based mesh implant in femoropopliteal bypass surgery: a Case Report

Treatment of patients with peripheral artery diseases is one of the most difficult issues in vascular surgery. The overall prevalence of peripheral arterial disease varies from 3-10% among the population aged 40-59 years old and among people over 70 years old - up to 15-20%. In the majority of cases atherosclerosis is the main cause of peripheral arterial disease. Autovein is considered a prosthesis of choice and is the most commonly used graft in the bypass surgery. However, it has been deemed impossible in 30% of cases due to its diameter, length or varicose lesions. Despite the technical advances, has not yet developed an ideal vascular prosthesis. Thus, there is a need of search for new materials and modifications of available materials, with the goal of creating a prosthesis for properties close to ideal. In this article we present first case report in the world about usage xenograft with protective external tubular mesh made from superelastic shape-memory nitinol as bypass material. This case shows that the xenoprosthesis with external tubular nitinol mesh support for prophylaxis of aneurysm formation can be used as vascular conduits in bypass surgery. Further randomized controlled trials needed

Clinical assessment of xenograft combined with knitted TiNi-based mesh implant in femoropopliteal bypass surgery: a Case Report

Treatment of patients with peripheral artery diseases is one of the most difficult issues in vascular surgery. The overall prevalence of peripheral arterial disease varies from 3-10% among the population aged 40-59 years old and among people over 70 years old - up to 15-20%. In the majority of cases atherosclerosis is the main cause of peripheral arterial disease. Autovein is considered a prosthesis of choice and is the most commonly used graft in the bypass surgery. However, it has been deemed impossible in 30% of cases due to its diameter, length or varicose lesions. Despite the technical advances, has not yet developed an ideal vascular prosthesis. Thus, there is a need of search for new materials and modifications of available materials, with the goal of creating a prosthesis for properties close to ideal. In this article we present first case report in the world about usage xenograft with protective external tubular mesh made from superelastic shape-memory nitinol as bypass material. This case shows that the xenoprosthesis with external tubular nitinol mesh support for prophylaxis of aneurysm formation can be used as vascular conduits in bypass surgery. Further randomized controlled trials needed