Search

Cage instability or highly dynamic cage movement can have a strong influence on the performance of rolling bearings. In addition to very loud and disturbing noises (“squealing”), bearing failure du...

Among flourishing control studies on air-breathing hypersonic vehicles (AHVs), actuator characteristics have not been fully accommodated. This study gives a comprehensive consideration to physical ...

The Rotary-Motion Extended Array Synthesis spacecraft is a dual-spin spacecraft with long tethers held in tension by the spin. This paper derives the free-space (not considering orbital effects) dy...

Three-dimensional (3D) tracking of surface-tethered single particles reveals the dynamics of the molecular tether. However, most 3D tracking techniques lack precision, especially in the axial direction, for measuring the dynamics of biomolecules with a spatial scale of several nanometers. Here, we present a plasmonic imaging technique that can track the motion of ∼100 tethered particles in 3D simultaneously with sub-nanometer axial precision and single-digit nanometer lateral precision at millisecond time resolution. By tracking the 3D coordinates of a tethered particle with high spatial resolution, we are able to determine the dynamics of single short DNA and study its interaction with enzymes. We further show that the particle motion pattern can be used to identify specific and nonspecific interactions in immunoassays. We anticipate that our 3D tracking technique can contribute to the understanding of molecular dynamics and interactions at the single-molecule level.

Flow is thought to occur when both task difficulty and individual ability are high. Flow experiences are highly rewarding and are associated with well-being. Importantly, media use can be a source of flow. Communication scholars have a long history of theoretical inquiry into how flow biases media selection, how different media content results in flow, and how flow influences media processing and effects. However, the neurobiological basis of flow during media use is not well understood, limiting our explanatory capacity to specify how media contribute to flow or well-being. Here, we show that flow is associated with a flexible and modular brain-network topology, which may offer an explanation for why flow is simultaneously perceived as high-control and effortless, even when the task difficulty is high. Our study tests core predictions derived from synchronization theory, and our results provide qualified support for the theory while also suggesting important theoretical updates.

With the increased demand for controlled deterministic growth of III–V semiconductors at the nanoscale, the impact and interest of understanding defect formation and crystal structure switching becomes increasingly important. Vapor–liquid–solid (VLS) growth of semiconductor nanocrystals is an important mechanism for controlling and studying the formation of individual crystal layers and stacking defects. Using in situ studies, combining atomic resolution of transmission electron microscopy and controlled VLS crystal growth using metal organic chemical vapor deposition, we investigate the simplest achievable change in atomic layer stacking–single twinned layers formed in GaAs. Using Au-assisted GaAs nanowires of various diameters, we study the formation of individual layers with atomic resolution to reveal the growth difference in forming a twin defect. We determine that the formation of a twinned layer occurs significantly more slowly than that of a normal crystal layer. To understand this, we conduct thermodynamic modeling and determine that the propagation of a twin is limited by the energy cost of forming the twin interface. Finally, we determine that the slower propagation of twinned layers increases the probability of additional layers nucleating, such that multiple layers grow simultaneously. This observation challenges the current understanding that continuous uniform epitaxial growth, especially in the case of liquid-metal assisted nanowires, proceeds one single layer at a time and that its progression is limited by the nucleation rate.

The paper presents a software platform made with LabVIEWTM for the assisted research of the kinematic and dynamic behavior of industrial robots. The platform comprises a series of virtual instrumentation LabVIEWTM programs (subVI-s) with: the input data modules in the form of several clusters with the parameters of the trapezoidal velocity characteristics of each joint, the axes of movement and the type of each joints, the dimensions of each body, the graph associated to the robot’s structure, the incidence matrices bodies - joints and joints- bodies, as well as the control buttons for movement up or down with or without object in the end- effecter, some modules with 2D characteristics of positions, velocities, accelerations, forces and moments in each joints and also the 3D characteristics of them. The research of the current stage shows that such a complex platform like this was not realized, the current research being limited to the animation of motion trajectories, determining the characteristics of positions, velocities, accelerations, forces and moments without the possibility of changing all motion parameters and robot’s dimensions and without show how these parameters change the behavior. The paper studies the case of an articulated arm type robot, but the platform can be used for any type of robot with four degrees of freedom (DOF).

in presented paper the transient characteristics of an asynchronous electric drive of a pump unit with PID-similar fuzzy controller are investigated. A comparative analysis of control quality in a system with traditional and fuzzy controllers is performed. The use of fuzzy controller in the asynchronous electric drive of the pump unit for water supply system is substantiated and it is proved that the use of fuzzy logic leads to the improvement of the quality of the transient process of the system. The simulation was performed using the Scilab mathematical application package.

A control strategy based on H∞-type static output feedback combined with dynamic feed-forward is proposed to improve the high-speed lateral performance of an A-double combination vehicle(tractor–se...

The authors examined the composition of biocrystalline structures (anisomorphones) of blood serum in patients with laryngeal cancer. Such structures are formed when blood serum becomes solid, i.e. during its marginal dehydration. The revealed anisomorphones represent three types of marker structures: a marker of a malignant tumor active growth (the aggregation of macroferolite and granular microspherolite with the same degree of anisotropy); a marker of a degenerative-dystrophic process (the aggregation of a macrospherolite with a low degree of anisotropy and microspherolite with a high degree of anisotropy); a marker of a malignant growth progression (a wavy microspherolite without aggregation). The aim of the study is to identify diagnostic markers of the malignant process activity in the solid phase structures of the blood serum in patients with laryngeal cancer and to assess their importance for choosing an effective therapy. Materials and Methods. Marginal dehydration of blood serum was used as the main research method. It is a part of the "Litos-system" diagnostic technology (Marketing authorization FS No. 155, of 2009). Results. It has been shown that the developmental phase of laryngeal cancer (active growth or degenerative-dystrophic process) is an important criterion for choosing treatment options. Surgical treatment is the most effective during the degenerative-dystrophic tumor process, while radiation therapy is preferable during the active phase of malignant growth. Key words: laryngeal cancer, blood serum, marginal dehydration of biological fluids, markers of tumor growth activity. Исследован состав биокристаллических структур (анизоморфонов) сыворотки крови больных раком гортани, которые формируются при переходе сыворотки крови в твердую фазу в процессе ее краевой дегидратации. Выявленные анизоморфоны представляют собой три вида маркерных структур: маркер активного роста злокачественной опухоли – агрегация макросферолита и зернистого микросферолита с одинаковой степенью анизотропии; маркер дегенеративно-дистрофического процесса – агрегация макросферолита с низкой степенью анизотропии и микросферолита с высокой степенью анизотропии; маркер прогрессии злокачественного роста – волнистый микросферолит вне агрегации. Цель – выявить диагностические маркеры активности злокачественного процесса в структурах твердой фазы сыворотки крови больных раком гортани и оценить их значение для выбора эффективного вида лечения. Материалы и методы. В качестве основного метода исследования использован метод краевой дегидратации сыворотки крови, являющийся разделом диагностической технологии «Литос-система» (Разрешение ФС № 155 от 2009 г. на применение в клинической практике). Результаты. Показано, что фаза развития рака гортани (активный рост или дегенеративно-дистрофический процесс) служит важным критерием выбора вида лечения: в фазу дегенеративно-дистрофического процесса опухоли наиболее благоприятный эффект дает хирургическое лечение, а в период активной фазы злокачественного роста – лучевая терапия. Ключевые слова: рак гортани, сыворотка крови, краевая дегидратация биологических жидкостей, маркеры фазы активности опухолевого роста.

We focus on studying the dynamics of bulk semiconductor optical amplifiers and their effects on the saturation region for short pulse that differ, however there is the same unsaturated gain for both dynamics. Parameters like current injection, fast dynamics present by carrier heating (CH), and spectra hole burning (SHB) are studied for regions that occur a response to certain dynamics. The behavior of the saturation region is found to be responsible for phenomena such as recovery time and chirp for the pulse under study.

Owing to the significant contribution of flexible modals in rigid-flexible multiple body system (MBS) dynamics, model updating before flex-body generation is necessary. Herein, a model-updating met...

The loudspeakers of thermal front are studied in the dried-out products in the Termika sunny drying setting of. An experimental stand is worked out for the study of dynamics of development of thermal front in the objects of drying, an experimental base is created for the conduct of experimental researches on the exposure of speed of distribution of temperature in the volume of object of drying. On the base of the created experimental stand experimental studies are undertaken in Termika, Individual SDS, and outdoors. Comparative data are got, characterizing the loud speakers of development of thermal front in the objects of drying. It is experimentally well-proven that presence of additional source of infrared in the chamber of drying as a metallic rib of perpendicular relatively overhead metallic sheet — heat-exchanger allows to promote speeds of drying.

One of the key problems in liquid-propellant rocket engine (LPRE) design is to provide the stability of LPRE working processes, in particular low-frequency stability. In LPRE experimental tryout, every so often there occur situations where the development of divergent oscillations set up in some of the LPRE loops or units results in contingencies: exceeding the engine ultimate strength, pump stall, chamber ignition, etc. Such contingencies may lead to grave consequences, including engine and bench equipment failure. Because of this, mathematical simulation is one of the main tools that allow one to predict he dynamic performance of an LPRE both in its steady operation and in transients and its startup operation features at the design and tryout stage. This paper overviews and analyzes scientific publications for the past 15 years concerned with the study of the dynamics and low-frequency stability of advanced LPREs and units thereof along different lines. This analysis made it possible to identify problems in low-frequency stability prediction and assurance for liquid-propellant rocket propulsion systems (LPRPSs) under design, to cover new research results (experimental and theoretical) on the origination and development of all-engine low-frequency oscillations and low-frequency oscillations in LPRPS systems and units and to identify new approaches to the mathematical simulation and study of low-frequency processes in LPRPSs and promising lines of investigation. The man lineы of the analysis are as follows: the low-frequency dynamics of cavitating inducer-equipped centrifugal pumps and LPRE gas paths, LPRE thrust control problems, the interaction of launch vehicle airframe longitudinal oscillations with low-frequency processes in the sustainer LPRPS, dynamic processes during an LPRE startup/shutdown, and low-frequency in-chamber oscillations.

The results of the study dealing with the level of neurotization in patients with cholelithiasis in dynamics on the 1st-2nd days after surgery, in 6 months and in 5 years after surgery are presented. The aim of the work was to study the impact of intracrisis psychotherapeutic intervention on the recovery of patients with cholelithiasis in the near and long term. Already on the 1st-2nd days after the operation, a decrease in situational anxiety was detected in patients who had undergone psychotherapy, and after 6 months all indicators of anxiety-depression disorders did not differ from those of healthy people, while in patients without psychotherapy, the indicators of situational, personal anxiety and depression remained significantly higher than those in the control group of healthy people. In 5 years after discharge, the primary incidence of non-psychotic mental disorders in patients with cholelithiasis was 20.3%, and in patients who underwent intracrisis intervention - 2.7%. Thus, the implementation of intracrisis psychotherapeutic intervention improves the long-term results of treatment of patients with cholelithiasis.

BACKGROUND AND PURPOSE: Arterial sclerosis resulting from hypertension slows CSF transportation in the perivascular spaces, showing the intrinsic relationship between the CSF and the blood vasculature. However, the exact effect of hypertension on human CSF flow dynamics remains unclear. The present study aimed to evaluate CSF flow dynamics in treatment-naive patients with essential hypertension using phase-contrast cine MR imaging. MATERIALS AND METHODS: The study included 60 never-treated patients with essential hypertension and 60 subjects without symptomatic atherosclerosis. CSF flow parameters, such as forward flow volume, forward peak velocity, reverse flow volume, reverse peak velocity, average flow, and net flow volume, were measured with phase-contrast cine MR imaging. Differences between the 2 groups were assessed to determine the independent determinants of these CSF flow parameters. RESULTS: Forward flow volume, forward peak velocity, reverse flow volume, reverse peak velocity, and average flow in the patients with hypertension significantly decreased (all, P

In the paper, a combined model of traction and ball bearings dynamics is established, considering the interaction among the cage, races, and balls. A curve-fitted traction model, which can be used to analyze the effect of the geometry of the bearing and parameters of the lubricant, is applied. The traction that is affected by certain parameters is analyzed; then, the effect of the traction on ball bearings is investigated. The displacements of balls and contact angles are different under different surface roughness. The changes in displacements of balls and contact angles are obtained with different roughness, load, and velocities. The amplitudes of axial displacement of balls are bigger with the roughness being higher. The amplitudes of ball-inner contact angles increase with greater roughness, and the amplitudes of ball-outer race contact angles decrease with greater roughness. The simulated vibration results of ball bearings under different levels agree with the actual by the model.

During active object manipulation, the finger-object interactions give rise to complex fingertip skin deformations. These deformations are in turn encoded by the local tactile afferents and provide rich and behaviorally relevant information to the central nervous system. Most of the work studying the mechanical response of the finger to dynamic loading has been performed under a passive setup, thereby precisely controlling the kinematics or the dynamics of the loading. However, to identify aspects of the deformations that are relevant to online control during object manipulation, it is desirable to measure the skin response in an active setup. To that end, we developed a device that allows us to monitor finger forces, skin deformations, and kinematics during fine manipulation. We describe the device in detail and test it to precisely describe how the fingertip skin in contact with the object deforms during a simple vertical oscillation task. We show that the level of grip force directly influences the fingerpad skin strains and that the strain rates are substantial during active manipulation (norm up to 100%/s). The developed setup will enable us to causally relate sensory information, i.e. skin deformation, to online control, i.e. grip force adjustment, in future studies.

Despite the common use of the prostate-specific antigen (PSA) serum level as a tumour marker in diagnosis of prostate cancer, it seems that the PSA doubling time (PSADT) and PSA velocity (PSAV) could be more useful indicators of tumour behaviour and prognosis for patients. The aim of the study was to evaluate the value of PSAV and PSADT in the diagnosis of prostate cancer and their relationship with prostate cancer histopathological characteristics. Eighty-six patients undergoing radical prostatectomy were enrolled in the study. Based on the PSA measurements the PSA dynamic values were calculated: PSADT and PSAV. In addition, clinical and histo-pathological characteristics, including disease stage and prognostic groups were evaluated. The obtained results showed that the first PSA value was 4.29 ng/ml (1.28–13.56), the second PSA value was 7.76 ng/ml (7.60–47.60), and the third PSA value was 9.67 ng/ml (2.56–98.50). The median PSADT was 51.01 months (7.80–311.81) and the median PSAV was 2.66 ng/ml/per year (0.22–4.66). In addition, significant correlations between PSAV and pre- and post-operative Gleason score, and prognostic groups were observed. Significant correlation between PSADT and pre- and pos-toperative Gleason score and prognostic risk groups was demonstrated. This study demonstrated that PSAV and PSADT were significantly correlated with postoperative Gleason score and prognostic risk groups, demonstrating its role in the diagnosis of prostate cancer progression.

Актуальность. Иммунная система представляет собой совокупность лимфоидной ткани, которая во взаимосвязи с другими адаптационными системами организма осуществляет специфический антигенно-структурный гомеостаз внутренней среды. Поэтому цель данного исследования — изучение динамики маркеров клеточного звена иммунитета у больных с повышенным индексом массы тела (ИМТ) при политравме. Материалы и методы. У 224 больных с политравмой с разной стартовой цифрой ИМТ в период 1-й день — 1 год с момента получения повреждений было проанализировано иммунологическое состояние — субпопуляционный состав лимфоцитов. Пациенты имели одинаковую тяжесть состояния на момент поступления по шкале АРАСНЕ ІІ — 14,0 ± 5,8 балла и были распределены на 3 стратифицированные клинические группы в зависимости от стартовых цифр антропометрических показателей и ИМТ. Так, в I группу вошли 88 пациентов с ИМТ на момент поступления до 29,9 (26,1 ± 3,1) кг/м2; во II группу — 84 больных с ИМТ на момент поступления 30,0–39,9 (35,2 ± 3,8) кг/м2; в III группу — 52 больных с ИМТ на момент поступления > 40,0 (46,2 ± 5,8) кг/м2. Контрольную группу составили 60 добровольцев. Исследование проводилось на 1-е, 3-и, 7, 14, 30 и 360-е сутки с момента получения политравмы. Результаты. Для больных с ИМТ ≥ 29,9 кг/м2 характерен кратковременный слабовыраженный дисбаланс регуляторных Т-клеток и Т-дефицит, что максимально проявляется в первую неделю заболевания, носит приспособительный характер, раннее восстановление (до 14-х суток) функций клеточного иммунитета, отсутствие следовой реакции в отдаленные сроки. Для больных с ИМТ 30,0–39,9 кг/м2 характерен Т-дефицит, что максимально проявляется в течение первого ее месяца, сочетается с незначительным дисбалансом субпопуляций Т-лимфоцитов, снижением мембранных функций этих клеток в сроки до 1 месяца, наличием удаленной неинтенсивной следовой реакции в виде снижения количества Т-лимфоцитов, Т-супрессоров, Т-активных лимфоцитов до нижней границы нормальных значений, высокоамплитудные колебания Т-хелперов/индукторов, с нарушением мембранных функций в сроки до 1 года. Для больных с ИМТ ≥ 40,0 кг/м2 характерен Т-дефицит во все сроки обследования с максимально выраженной интенсивностью. Наибольшие его проявления были определены в первый месяц болезни и сохранялись даже до 1 года. Отмечено снижение Т-лимфоцитов на 40 % и более от нормальных значений, которое сохранялось более одной недели и не имело тенденции к дальнейшему росту, прогрессирующее снижение Т-активных лимфоцитов более чем на 40 %, что сопровождалось выраженным нарушением взаимодействия регуляторных Т-клеток (Т-хелперов и Т-супрессоров). Выводы. Таким образом, у больных с повышенным индексом массы тела в каждой из групп сравнения был обнаружен индивидуальный ответ на механическую травму, что, скорее всего, обусловлено стартовым ИМТ исследуемых пациентов.

The goal of the research was to clarify the regularities of the dynamics of gas release from the surface of the outcrop of the developed coal seam. The main research methods were theoretical methods of mathematical physics and non-equilibrium thermodynamics. Gas-bearing coal seams are usually mined underground. When driving development workings, outcropping surfaces of gas-bearing coal seams appear and gases in the seams under excessive pressure are released into the atmosphere of the mine workings. Gas-bearing coal seams are usually mined underground. When driving preparatory workings, surfaces of outcropping of gas-bearing coal seams arise and gases that are in the seams under excessive pressure are released into the atmosphere of the mine workings. The most important gas-dynamic characteristic of this process is the rate of gas release, which represents the volume of gases released from a unit area of exposure of a coal seam per unit of time. A generalized law of resistance for gas filtration in a rock mass is recommended, and a fairly rigorous thermodynamic substantiation is given. It is shown that the densities of gas mass flows in accordance with the postulate of their linear relationship with the driving forces are determined by the Onsager relation. The results obtained and their discussion is presented. Mathematical models are proposed for engineering calculations of the dynamics of methane release from the outcropping surface of medium-thick coal seams. The error of the adopted approximations does not exceed 3%. The intensity of methane release is directly related to the planogram of work in the working face. Analysis of this dependence indicates that during the extraction cycle, methane release increases due to an increase in the area of the gas-release surface. The main conclusions are as follows: mathematical modeling of the processes of gas movement in a porous sorbing medium using approximate mathematical models representing linearized equations of mathematical physics; the regularities of the dynamics of the rate of gas release from the surface of the outcrop of a gas-bearing coal seam is the theoretical basis for the mathematical description of the process of gas release; the use of a linearized hyperbolic filtration equation most accurately describes the processes of methane release from the outcropping surface of mined coal seams.

In our work we aimed to conduct a fundamental study of the process of morphological disorganization of the structural components of the mucous membrane and cartilage of the larynx at the end of the 28 and 35 days of experimental opioid effects at the microstructural level. This information in the future will allow to form a pathomorphological base, which will be used to compare the components of the mucous membrane and cartilage of the larynx in the norm with the dynamics of their changes as a result of experimental opioid effects at different times.

This paper represents a new mathematical model for helicopters with flexible fuselages. The theory connects the two commonly separated research areas of flight, dynamics and structural dynamics, by...

In this paper we study the $p$-adic dynamics of prime-to-$p$ Hecke operators on the set of points of modular curves in both cases of good ordinary and supersingular reduction. We pay special attention to the dynamics on the set of CM points. In the case of ordinary reduction we employ the Serre-Tate coordinates, while in the case of supersingular reduction, we use a parameter on the deformation space of the unique formal group of height $2$ over $\overline{\mathbb{F}}_p$, and take advantage of the Gross-Hopkins period map.

The nonlinear absorption of two-dimensional (2 D) Nb2CTx (MXene) nanosheets were investigated by using nanosecond Z-scan measurements in 532 nm under different laser intensities. It was found that,...

A differential mechanism is an essential component in the majority of automotive applications. Its vitality stems from the fact that it allows a wheel-drive vehicle to take a curve safely. On the other hand, it can ratchet up the vibration in the wheel-drive vehicle due to the excessive gear tooth deflection from applied torque. Some gear tooth modifications can increase or decrease the level of vibration in the mechanism. So far, very little attention has been paid to the effects of the uncertain geometric deviation of the tooth profile and uncertain crowning parameters on the dynamic performance of the mechanism. This study aims to investigate the impacts of these uncertain parameters on the gear systems’ dynamic performance. To this end, the nonlinear interval model of the differential mechanism is proposed. The mesh stiffness for straight bevel gear is modelled through the potential energy method and slice theory, while bearing stiffness elements are calculated at each time step. A refined computational algorithm is proposed to deal with any gear system with multiple interval variables. The scanning method is used as a reference method in this paper. The main outcomes of this study are that the crowning design can slightly reduce the vibration in the mechanism, and the profile errors can increase its vibration level excessively. Besides, the results derived from the refined algorithm show similarities to those determined by the scanning method, and the study shows that the refined algorithm can handle any gear system with uncertain static or time-varying parameters.

The structure of information technology for modeling control systems, which includes a block of systems models, a module of integration methods and other program elements, is considered. To analyze the dynamics of control of a nuclear reactor, programs of mathematical models of a WWER-1000 nuclear reactor of the V-320 series and its control systems in the form of nonlinear systems of differential equations in the Cauchy form have been developed. For the integration of nonlinear systems of differential equations, an algorithm of the system method of the first degree is presented. A mathematical model of a WWER-1000 reactor as a control object with division into zones along the vertical axis in relative variables of state is considered, the values of the constant parameters of the model and the initial conditions corresponding to the nominal mode are given. Using information technology for ten zones of the reactor, the system integration method was used to simulate the dynamics of control of a nuclear reactor. Graphs of neutron and thermal processes in the reactor core, as well as changes in the axial offset when the reactor load is dumped under the influence of the movement of absorbing rods and an increase in the concentration of boric acid, are plotted. The analysis of dynamic processes of reactor control is carried out. The programs of integration methods and models of the WWER-1000 reactor of the V-320 series are included in the information technology to optimize the maneuvering modes of the reactor.

The purpose of the study was by means of modern software to explore working processes taking place in automatic direct-acting pressure regulators of pneumatic spacecraft systems. As a result, we developed a general mathematical model of the pressure regulator. The design of the regulator is shown in the form of a block diagram, composed of a set of channels, cavities, and stages. The elements of the block diagram are interconnected by the basic laws of conservation of energy and mass. The mathematical model was evaluated in the Amesim software package. Findings of the full-scale and computational experiments led to the conclusions about the effect the heat exchange between the working fluid and the environment produces on the parameters of the pressure regulator, and about the use of the Amesim software package for further research of working processes in the valve units of pneumatic systems.

This study investigated the rollover phenomenon of a self-propelled combine harvester during short-distance cross-region travel on a road. The mathematical model of the unsteady lateral multi-degree-of-freedom (multi-DOF) motion of the combine harvester was established with consideration to rear wheel steering, front wheel braking, wheel sideslip, and tyre lateral deflection. By carrying out complex kinematics analysis for the entire vehicle and rotational dynamics analysis for the wheels, the mathematical relationships among the lateral deflection angles of the tyres, the kinematic parameters of the combine harvester centroid, the steering angles of the rear wheels, and the speed components of the wheel centroids along their longitudinal directions were derived and used to transform the established mathematical model into a novel form that considers the steering angles and kinematic parameters as unknown quantities. The lateral load transfer ratio (LTR) model of the combine harvester was established to assess the harvester's rollover critical state. Finally, by considering the steering angles of the rear wheels and the braking torque of the front wheels as model inputs, the rollover mechanism and effects of the structural geometry, steering angles, and braking torque on the LTR of the combine harvester were revealed through numerical calculation, and the safety intervals of the parameters were obtained. The results obtained by this study can provide theoretical and technical support for the dynamic design, control, and rollover protection of combine harvesters.

A review of well-known publications is given and some results of the authors’ research on modeling the dynamics of systems of rigid bodies and exoskeletons are presented. Various approaches to the problem of modeling the dynamics of multilink systems are described, including the problems of constructing equations of motion and solving control problems. Matrix and recurrent methods of composing equations for the dynamics of anthropomorphic mechanisms and exoskeletons, as well as problems of modeling flat and spatial systems containing links of variable length, are considered. The results of the research on the analytical design of exoskeletons, anthropomorphic mechanisms, and their analogs seem to be relevant for the design of systems designed to enhance human motor functions and the development of robotic systems for various purposes.

The implementation of state programs in the feld of health protection, in particular to combat excessive alcohol consumption and associated mortality, naturally entails the need for regular and thorough monitoring the relevant indicators and determine the effectiveness of the measures taken. The authors of the study, in order to determine the dynamics of the rates of alcohol poisoning fatal cases, carried out an analysis of the statistical data. It is concluded that there is a tendency towards a gradual decrease in the studied indicator in various federal districts of Russian Federation, which determines the effectiveness of measures taken to combat excessive alcohol consumption, and also federal districts were identifed where additional measures are required.

In this study, an equivalent multi-body dynamics model of a rotary compressor for a household air-conditioner is established to predict its vibration responses when eccentric masses on the cranksha...

Dynamic responses and vibration characteristics of a rotating functionally graded material (FGM) beam with a hollow circular cross-section in the temperature field are investigated in this paper. The material properties of the FGM beam are assumed to be temperature-dependent and vary along the thickness direction of the beam. By considering the rigid-flexible coupling effect, the geometrically nonlinear dynamic equations of a hub–FGM beam system are derived by employing the assumed modes method and Lagrange’s equations. With the high-order coupling dynamic model, the effect of temperature variations under two different laws of motion is discussed, and the free vibration of the system is studied based on the first-order approximate coupling model. This research can provide ideas for the design of space thermal protection mechanisms.

The neuromuscular system responds to perturbation and increasing locomotor task difficulty by altering the stability of neuromuscular output signals. The purpose of this study was to determine the effects of two different military load carriage systems on the dynamic stability of gait and muscle activation signals. 14 army office cadets (20 ± 1 years) performed 4-minute treadmill walking trials on level (0%) and uphill (10%) gradients while unloaded, and with 11 kg backpack and 11 kg webbing loads while the activity of 6 leg and trunk muscles and the motion of the centre of mass (COM) were recorded. Loaded and uphill walking decreased stability and increased magnitude of muscle activations compared to loaded and level gradient walking. Backpack loads increased the medio-lateral stability of COM and uphill walking decreased stability of vertical COM motion and increased stride time variability. However, there was no difference between the two load carriage systems for any variable. The reduced stability of muscle activations in loaded and uphill conditions indicates an impaired ability of the neuromuscular control systems to accommodate perturbations in these conditions which may have implications on the operational performance of military personnel. However, improved medio-lateral stability in backpack conditions may indicate that participants were able to compensate for the loads used in this study, despite the decreased vertical stability and increased stride time variability evident in uphill walking. This study did not find differences between load carriage systems however, specific load carriage system effects may be elicited by greater load carriage masses.Highlights Loaded and uphill walking decreased dynamic stability of muscle activationsLower activation stability indicates impaired neuromotor resistance to perturbationBackpack and webbing loads produced similar effects on muscle activations.

Simulations of human body motion involve different fields of study such as robotics, from nano to macroscale, and biomechanics. The simulation of human motion is a challenging problem from the physical and computational perspectives and several models have been proposed in literature. Using a methodology named predictive dynamics, this work aims to propose a 2D spatial model of human walking during the single stance phase (SSP), using a flat foot adaptation. The model is based on inverse dynamics in which the angular displacements are interpolated by 5th degree B-splines. The equation of motion is developed by the recursive Lagrangian formulation due to its computational efficiency. An optimization problem is set up to obtain the control points of the B-splines using as the objective function the dynamic effort, which is a limited power supply. The constraints imposed on the motion are time-dependent, such as the torque/angle limits, and the dynamic stability criterion defined by the zero moment point (ZMP), or time-independent, such the equation of motion and step length. All the steps are explained in detail to find the dynamics of the body using the smallest number of laboratory results. The solution from the model is favorably compared to Winter’s data, in particular the ground reaction forces, which is important in many engineering applications.

Derivatives of equations of motion (EOM) describing the dynamics of rigid body systems are becoming increasingly relevant for the robotics community and find many applications in design and control of robotic systems. Controlling robots, and multibody systems comprising elastic components in particular, not only requires smooth trajectories but also the time derivatives of the control forces/torques, hence of the EOM. This paper presents the time derivatives of the EOM in closed form up to second-order as an alternative formulation to the existing recursive algorithms for this purpose, which provides a direct insight into the structure of the derivatives. The Lie group formulation for rigid body systems is used giving rise to very compact and easily parameterized equations.

Aim: to establish the patterns of changes in leukocyte blood parameters to determine their diagnostic significance in the different activity of Crohn’s disease (CD) and ulcerative colitis (UC) in children. Materials and methods. 370 5-18-year children (198 boys, 172 girls) with inflammatory bowel disease (IBD) were examined. Leukocytic blood parameters, concentrations of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), faecal calprotectin (FC) levels were determined. Changes in clinical activity in Crohn’s disease (CD) and ulcerative colitis (UC) cases were determined using pediatric activity indices: PCDAI and PUCAI, respectively. Analysis of endoscopic activity in 160 CD and UC patients was determined using the scales: SES-CD and UCEIS, respectively. Results. It was found that with an increase in the clinical activity of CD in children, the absolute numbers of leukocytes, lymphocytes and monocytes did not change significantly. In contrast, a significant increase in neutrophil reactivity was noted. In patients with high endoscopic CD activity an increase in the absolute number of monocytes and neutrophil reactivity was found. In patients with high clinical activity of UC, an increase in the number of leukocytes and the absolute number of neutrophils was found. At the same time, the granularity and reactivity of neutrophils increased from remission to moderate and high clinical activity of UC. In children with high endoscopic UC activity, the number of leukocytes, the absolute number of neutrophils and monocytes increased. At the same time, the granularity of neutrophils significantly increased as the endoscopic activity of UC increased from remission to moderate activity. Leukocyte parameters in UC patients correlated moderately with FC level, and the absolute number of neutrophils was closely related to its content. The granularity and reactivity of neutrophils positively correlated with ESR and CRP levels in children with CD and CRP concentrations in children with UC. Conclusion. The established patterns of changes in the quantitative composition of leukocytes and their functional properties (reactivity and granularity) are directly determined by the different activity of IBD in children and have diagnostic value