scholarly journals Determining the energy efficiency of a resonance single-mass vibratory machine whose operation is based on the Sommerfeld effect

2021 ◽  
Vol 5 (7 (113)) ◽  
pp. 44-51
Author(s):  
Volodymyr Yatsun ◽  
Gennadiy Filimonikhin ◽  
Irina Filimonikhina ◽  
Antonina Haleeva
Keyword(s):  
Energy Efficiency ◽  
Angular Speed ◽  
The Body ◽  
Total Power ◽  
Simultaneous Increase ◽  
Vibration Exciter ◽  
Viscous Resistance ◽  
Sommerfeld Effect ◽  
Combined Load ◽  
Internal Forces

This paper reports determining the energy efficiency of a vibratory machine consisting of a viscoelastically fixed platform that can move vertically, and a vibration exciter whose operation is based on the Sommerfeld effect. The body of the vibration exciter rotates at a steady angular speed while there are the same loads in the form of a ball, a roller, or a pendulum inside it. The load, being moved relative to the body, is exposed to the forces of viscous resistance, which are internal within the system. It was established that under the steady oscillatory modes of a vibratory machine's movement, the loads are tightly pressed to each other, thereby forming a combined load. Energy is productively spent on platform oscillations and unproductively dissipated due to the movement of the combined load relative to the body. With an increase in the speed of the body rotation, the increasing internal forces of viscous resistance bring the speed of rotation of the combined load closer to the resonance speed, and the amplitude of platform oscillations increases. However, the combined load, in this case, increasingly lags behind the body, which increases unproductive energy loss and decreases the efficiency of the vibratory machine. A purely resonant motion mode of the vibratory machine produces the maximum amplitude of platform oscillations, the dynamic factor, the total power of viscous resistance forces. In this case, the efficiency reaches its minimum value. To obtain vigorous oscillations of the platform with a simultaneous increase in the efficiency of the vibratory machine, it is necessary to reduce the forces of viscous resistance in supports with a simultaneous increase in the internal forces of viscous resistance. An algorithm for calculating the basic dynamic characteristics of the vibratory machine's oscillatory motion has been built, based on solving the problem parametrically. The accepted parameter is the angular speed at which a combined load gets stuck. The effectiveness of the algorithm has been illustrated using a specific example

Improving the efficiency of oilfield electric power distribution

2019 ◽  
pp. 79-87
Author(s):  
Yu. F. Yu. F. Romaniuk ◽  
О. V. Solomchak ◽  
М. V. Hlozhyk
Keyword(s):  
Power Distribution ◽  
Reactive Power ◽  
Power Transmission ◽  
Transmission Efficiency ◽  
Active Power ◽  
Oil Field ◽  
Total Power ◽  
Simultaneous Increase ◽  
Active Load ◽  
Step Down

The issues of increasing the efficiency of electricity transmission to consumers with different nature of their load are considered. The dependence of the efficiency of the electric network of the oil field, consisting of a power line and a step-down transformer, on the total load power at various ratios between the active and reactive components of the power is analyzed, and the conditions under which the maximum transmission efficiency can be ensured are determined. It is shown by examples that the power transmission efficiency depends not only on the active load, but also largely on its reactive load. In the presence of a constant reactive load and an increase in active load, the total power increases and the power transmission efficiency decreases. In the low-load mode, the schedule for changing the power transmission efficiency approaches a parabolic form, since the influence of the active load on the amount of active power loss decreases, and their value will mainly depend on reactive load, which remains unchanged. The efficiency reaches its maximum value provided that the active and reactive components of the power are equal. In the case of a different ratio between them, the efficiency decreases. With a simultaneous increase in active and reactive loads and a constant value of the power factor, the power transmission efficiency is significantly reduced due to an increase in losses. With a constant active load and an increase in reactive load, efficiency of power transmission decreases, since with an increase in reactive load, losses of active power increase, while the active power remains unchanged. The second condition, under which the line efficiency will be maximum, is full compensation of reactive power.  Therefore, in order to increase the efficiency of power transmission, it is necessary to compensate for the reactive load, which can reduce the loss of electricity and the cost of its payment and improve the quality of electricity. Other methods are also proposed to increase the efficiency of power transmission by regulating the voltage level in the power center, reducing the equivalent resistance of the line wires, optimizing the loading of the transformers of the step-down substations and ensuring the economic modes of their operation.

THE USE OF HEART RATE TELEMETRY FOR DYNAMIC CONTROL OF THE FUNCTIONAL STATE DURING COMPUTER TESTING AND BIOFEEDBACK IN KNOWLEDGE WORKERS

2021 ◽  
Author(s):  
M.M. Nekrasova ◽  
◽  
I.V. Fedotova ◽  
S.A. Polevaya ◽  
Keyword(s):  
Heart Rate ◽  
Functional State ◽  
Work Experience ◽  
Knowledge Workers ◽  
Management Strategies ◽  
Dynamic Control ◽  
The Body ◽  
Biofeedback Training ◽  
Total Power ◽  
Neurohumoral Regulation

Abstract: Introduction. Increasing information loads can lead to the development of professional stress and work-related illnesses in knowledge workers. The development and implementation of modern methods of control and correction of the functional state of employees in the conditions of activity is relevant. The study aims – to explore the dynamics of the functional state of knowledge workers in the conditions of modeling the cognitive load on the computer and during the training on neurofeedback (NFB) based on the parameters of the electroencephalogram (EEG). Materials and methods. 17 researchers (4 men and 13 women aged 22-63 years (34.8±3.4), with an average work experience of 12.1±3.3 years) participated in the study on the basis of voluntary informed consent. Results. A significant increase in the index of the alpha rhythm was shown by 29.4% of the subjects. It was found that the total power of the spectrum of heart rate variability (HRV) is higher, the adaptive risk is lower in the group that successfully passed alpha training (p<0.05). According to the results of continuous personalized heart rate telemetry, the dynamics of the functional state (FS) during the examination was determined for each subject. Conclusion. A significant influence of the state of neurohumoral regulation systems and adaptive reserves of the body on the success of the biofeedback training was established, which is the basis for the development of methodological approaches to the correction of FS, taking into account individual optimal management strategies.

STATE OF AUTONOMIC REGULATION OF HEART RHYTHM IN YOUNG AND AGED RATS BEFORE AND AFTER APPLICATION OF DIFFERENT REGIMENS OF RHYTHMIC EXTREME COOLING

2020 ◽  
pp. 436-443
Author(s):  
В. В. Кулик ◽  
В. Г. Бабийчук
Keyword(s):  
Heart Rate ◽  
Metabolic Regulation ◽  
Experimental Studies ◽  
Autonomic Regulation ◽  
The Body ◽  
Total Power ◽  
Aged Rats ◽  
Cooling Mode ◽  
Adaptive Capabilities ◽  
Extreme Cold

В работе изучено влияние разных режимов ритмических экстремальных холодовых воздействий на состояние вегетативной регуляции сердечного ритма у молодых и старых крыс. По данным спектрального анализа вариабельности сердечного ритма установлено, что у молодых крыс использование температурных режимов ритмических экстремальных холодовых воздействий, РЭХВ (-120 °С; -120 °С; -120 °С) и (-60 °С; -120 °С; -120 °С) значительно повышало адаптационные возможности организма за счет активации собственных гомеостатических регуляторных систем. При этом комбинированный режим РЭХВ (-60 °С; -120 °С; -120 °С) оказался наиболее оптимальным для старых животных, поскольку его применение не сопровождалось чрезмерной активацией симпатико-адреналовой системы на ранних этапах экспериментальных исследований в отличие от режима (-120 °С; -120 °С; -120 °С). Кроме того, использование данного режима охлаждения способствовало статистически значимому увеличению показателей общей мощности спектра нейрогуморальной регуляции не столько за счет повышения активности гуморально-метаболического звена регуляции, преобладание которого характерно для пожилого возраста, сколько благодаря увеличению тонуса вегетативных центров, причем парасимпатические влияния на миокард превалировали над симпатическими. The influence of various rhythmic extreme cold effects on the state of autonomic regulation of heart rate in young and aged rats was studied. According to the spectral analysis of heart rate variability, it has been found that in young rats, using rhythmic extreme cold exposures (RECE) temperature regimens of (-120 °С; -120 °С; -120 °С) and (-60 °С; -120 °С; -120 °С) significantly increased adaptive capabilities of the body due to the activation of its own homeostatic regulatory systems. At the same time, the combined regimen of RECE (-60 °С; -120 °С; -120 °С) occurred to be the most optimal for aged animals, since its use was not accompanied with an excessive activation of sympathoadrenal system at the early stages of experimental studies, in contrast to the regimen (-120 °С; -120 °С; -120 °С). In addition, the use of this cooling mode contributed to a statistically significant increase in the total power of spectrum of neurohumoral regulation not so much due to a rise in activity of humoral-metabolic regulation link, the prevalence of which is characteristic of an old age, but due to an increase in the tone of vegetative centers, herewith the parasympathetic effects on the myocardium prevailed sympathetic ones.

A case of thermal boundary-layer separation by a magnetic field

1970 ◽  
Vol 67 (3) ◽  
pp. 671-676
Author(s):  
E. R. D'sa
Keyword(s):  
Thermal Boundary Layer ◽  
Field Component ◽  
Magnetic Force ◽  
Blunt Body ◽  
Boundary Layer Separation ◽  
Angular Speed ◽  
External Flow ◽  
The Body ◽  
Force Coefficient ◽  
Diffusivity Ratio

In (1) the velocity and magnetic fields were studied in the stagnation point region of a magnetized blunt body rotating with angular speed Ω. Some familiarity with this paper is assumed here: briefly, the nose section of the body was approximated by a disc of thickness t and conductivity σ′ and a perturbation solution was derived for small values of the diffusivity ratio ε (= ν/λ) and of the magnetic force coefficient N = σB2/4ρa. B is the uniform normal field component at the upperside (z = 0) of the disc, a is the strength of the external flow, p and σ are the density and conductivity of the fluid. The other two governing parameters are ω = Ω/a and β = σ′/σL, where L = (λ/a)½.

A New Approach to Animal Flight Mechanics

1979 ◽  
Vol 80 (1) ◽  
pp. 17-54 ◽  
Author(s):  
J. M. V. RAYNER
Keyword(s):  
Body Mass ◽  
Large Body ◽  
Simple Expression ◽  
The Body ◽  
Flight Mechanics ◽  
Total Power ◽  
Forward Flight ◽  
Vortex Theory ◽  
Rate Of Increase ◽  
Total Power Consumption

The mechanics of lift and thrust generation by flying animals are studied by considering the distribution of vorticity in the wake. As wake generation is not continuous, the momentum jet theory, which has previously been used, is not satisfactory, and the vortex theory is a more realistic model. The vorticity shed by the wings in the course of each powered stroke deforms into a small-cored vortex ring; the wake is a chain of such rings. The momentum of each ring sustains and propels the animal; induced power is calculated as the rate of increase of wake kinetic energy. A further advantage of the vortex theory is that lift and induced drag coefficients are not required; estimated instantaneous values of these coefficients are generally too large for steady state aerodynamic theory to be appropriate to natural flapping flight. The vortex theory is applied to hovering of insects and to avian forward flight. A simple expression for induced power in hovering is found. Induced power is always greater than simple momentum jet estimates, and the discrepancy becomes substantial as body mass increases. In hovering the wake is composed of a stack of horizontal, coaxial, circular vortex rings. In forward flight of birds the rings are elliptic; they are neither horizontal nor coaxial because the momentum of each ring balances the vector sum of parasite and profile drag and the bird's weight. Total power consumption as a function of flight velocity is calculated and compared for several species. Power reduction is one of the major factors influencing the choice of flight style. A large body of data is used to obtain an approximate scaling between stroke period and the body mass for birds. Together with relations between other morphological parameters, this is used to estimate the variation of flight speed and power with body mass for birds, and on this basis deviations from allometric scaling can be related to flight proficiency and to the use of such strategies as the bounding flight of small passerines. Note: Present address: Department of Zoology, University of Bristol, Woodland Road, Bristol BS8 IUG, U.K.

Kinematic Mechanics Analysis of Takeoff in Pre-Jumping for Sports Aerobics

2014 ◽  
Vol 1014 ◽  
pp. 157-160 ◽  
Author(s):  
Zi Xin Zhu
Keyword(s):  
Influencing Factors ◽  
Mechanical Model ◽  
Angular Speed ◽  
The Body ◽  
Dynamics Analysis ◽  
Vertical Force ◽  
Bending Angle ◽  
Mechanics Analysis ◽  
Light Pole

Takeoff is important to a variety of difficult movements for sports aerobics. The paper analyzes the kinematic mechanics of takeoff in pre-jumping for the sport. It first discusses the importance of takeoff in sports aerobics, and finds that the mechanics theory can be utilized to analyze the forces produced in the process of takeoff. Then, the dynamics analysis of takeoff in pre-jumping is completed to reveal the change of the vertical force and expound the sports process from the aspect of mechanics. Subsequently, the body for the athlete is simplified a two-light-pole mechanical model. On the basis of this, the mechanics analysis of vertical force in pre-jumping is done to find the influencing factors for vertical force. The results show that the vertical force produced by the takeoff in pre-jumping suffers from the factors of the weight, length of leg, bending angle of knee, and angular speed of leg rotation, etc.

Spatially-Aware Optimization of Energy Consumption in Consolidated Data Center Systems

2011 ◽  
Author(s):  
Hui Chen ◽  
Mukil Kesavan ◽  
Karsten Schwan ◽  
Ada Gavrilovska ◽  
Pramod Kumar ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Data Center ◽  
Power Distribution ◽  
Total Power ◽  
Inlet Temperature ◽  
Workload Management ◽  
Thermal Distribution ◽  
Total Power Consumption ◽  
Application Requirements ◽  
Online Methods

Energy efficiency in data center operation depends on many factors, including power distribution, thermal load and consequent cooling costs, and IT management in terms of how and where IT load is placed and moved under changing request loads. Current methods provided by vendors consolidate IT loads onto the smallest number of machines needed to meet application requirements. This paper’s goal is to gain further improvements in energy efficiency by also making such methods ‘spatially aware’, so that load is placed onto machines in ways that respect the efficiency of both cooling and power usage, across and within racks. To help implement spatially aware load placement, we propose a model-based reinforcement learning method to learn and then predict the thermal distribution of different placements for incoming workloads. The method is trained with actual data captured in a fully instrumented data center facility. Experimental results showing notable differences in total power consumption for representative application loads indicate the utility of a two-level spatially-aware workload management (SpAWM) technique in which (i) load is distributed across racks in ways that recognize differences in cooling efficiencies and (ii) within racks, load is distributed so as to take into account cooling effectiveness due to local air flow. The technique is being implemented using online methods that continuously monitor current power and resource usage within and across racks, sense BladeCenter-level inlet temperatures, understand and manage IT load according to an environment’s thermal map. Specifically, at data center level, monitoring informs SpAWM about power usage and thermal distribution across racks. At rack-level, SpAWM workload distribution is based on power caps provided by maximum inlet temperatures determined by CRAC speeds and supply air temperature. SpAWM can be realized as a set of management methods running in VMWare’s ESXServer virtualization infrastructure. Its use has the potential of attaining up to 32% improvements on the CRAC supply temperature requirement compared to non-spatially aware techniques, which can lower the inlet temperature 2∼3°C, that is to say we can increase the CRAC supply temperature 2∼3°C to save nearly 13% −18% cooling energy.

scholarly journals The Kinematic Analysis of the Screw Conveyor Vibration Exciter

2019 ◽  
Vol 297 ◽  
pp. 03004
Author(s):  
Dmitriy Kobylyansky ◽  
Viacheslav Gogolin
Keyword(s):  
The Body ◽  
Calculation Scheme ◽  
Polar Coordinates ◽  
Screw Conveyor ◽  
Vibration Exciter ◽  
System Of Equations ◽  
Harmonic Oscillations ◽  
Triangle Center ◽  
The Given ◽  
Rotating Bodies

The article presents a method of calculating the parameters of the screw conveyor vibration exciter. The calculation scheme of the new design of the vibration exciter, which allows to determine the parameters of the vibrations excited by this device taking into account the structural novelty and the specifics of the vibration exciter, in particular, in the screw reloader is also given. A system of equations describing the harmonic oscillations of the auger shaft axis, including the amplitudes of horizontal and vertical oscillations, is presented. As a result, a system of parametric equations describing the external and internal envelope line is obtained. When solving the system of equations, the equations of the boundary curves of internal and external rotating bodies are derived. The equations allow to calculate the trajectory of any point by its given polar coordinates. Examples of rotating bodies for different types of displacements of the triangle center in the calculation scheme, which are described by harmonic oscillations, are shown. The dependences of the body shape on the direction of oscillations along the coordinate axes are illustrated. It is shown that the transition from horizontal to vertical oscillations leads to a loss of symmetry of the body. The amplitude and frequency of oscillations also have a significant impact on the shape of the body. The forms of the rotating bodies, giving the possibility of combining the rotation and oscillation when driving on rollers are determined. The problem is generalized to an arbitrary number of regularly arranged rollers. The given technique gives the principal opportunity to create designs of vibrators that combine vibrations with rotation on rollers.

Energy expenditure while performing gymnastic-like motion in spacelab during spaceflight: case study

2006 ◽  
Vol 31 (5) ◽  
pp. 631-634 ◽  
Author(s):  
Masahiro Kaneko ◽  
Kazuki Miyatsuji ◽  
Satoru Tanabe
Keyword(s):  
Energy Expenditure ◽  
Control Subject ◽  
Center Of Mass ◽  
Mechanical Efficiency ◽  
Video Camera ◽  
The Body ◽  
Mechanical Work ◽  
Whole Body ◽  
Total Power ◽  
External Work

To estimate energy cost of a gymnastic-like exercise performed by an astronaut during spaceflight (cosmic exercise), energy expenditure was determined by measuring mechanical work done around the center of mass (COM) of the body. The cosmic exercise, which consisted of whole-body flexion and extension, was performed during a spaceflight and recorded with a video camera. By analyzing the videotape, the internal mechanical work (Wint) against inertia load of the body segments was calculated. To compare how human muscles work on Earth, a motion similar to the cosmic exercise was performed by a control subject who had a physique similar to that of the astronaut. The total mechanical power of the astronaut was determined to be about 119 W; although the control subject showed a similar total power value, half of the power was external work (Wext) against gravitational load. By assuming a mechanical efficiency of 0.25, the energy expenditure was estimated to be 476 W or 7.7 W/kg, which is equivalent to that expended during fast walking and half of that used during moderate-speed running. Our results suggest that this form of cosmic exercise is appropriate for astronauts in space and can be performed safely, as there are no COM shifts while floating in a spacecraft and no vibratory disturbance.

scholarly journals DESIGN ANALYSIS AND CONSTRUCTION OF ENERGY HARVESTING COAXIAL HELICOPTER

Aviation ◽  
2013 ◽  
Vol 17 (4) ◽  
pp. 145-149
Author(s):  
Anvinder Singh ◽  
Varun Sharma
Keyword(s):  
Piezoelectric Sensor ◽  
Base Station ◽  
The Body ◽  
Total Power ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Aerial Vehicle ◽  
And Performance ◽  
A Charge ◽  
Coaxial Helicopter

With the growing need for technology, the tendency for errors has increased many times, which often results in loss of human lives. Our main aim of this paper is to show the implementation of a coaxial rotor aerial vehicle that can be controlled by a radio frequency transmitter. The helicopter is capable of manoeuvring in an area where real helicopters cannot. The area could be a flooded region, a place hit by an earthquake, or a building on fire. The main aim is to transmit video of that place to a base station by the camera attached to the helicopter. Various factors required to make a safe and successful coaxial helicopter are discussed and extensive flight testing proves that this flying machine is better in efficiency and performance than a traditional single rotor aerial vehicle. The relation of flight parameters like torque, induced power, rpm, pitch, and total power are discussed. A piezoelectric sensor is used to determine the vibrations occurring in the body so that they can be minimised. A successful attempt to convert the vibrations into a charge by piezoelectric energy harvesters is made.

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