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At a high frequency of vibration; the cam of a vibrator always encounters the issue of jamming or the follower rolling off or losing contact with the cam when the appropriate design is not carried out. This study, therefore, developed the shape of the cam profile of mechanical yam vibrator using cycloid motion.Displacement equations from the base circle to the cam profile were developed toobtain the shape of the cam using cycloid motion. A vibrometer was used toevaluate the developed 5 mm, 10 mm, and 20 mm cam sizes installed in amechanical yam vibrator. The maximum displacement recorded for 5 mm, 10 mmand 20 mm cam sizes were 4.47 mm, 8.71 mm, and 14.54 mm respectively for low (1 – 5 Hz) frequency; 4.58 mm, 8.84 mm and 16.34 mm respectively for medium (60 – 100 Hz) frequency; and 4.66 mm, 9.09 mm and 17.30 mm respectively for high (150 – 200 Hz) frequency. This study shows that a cycloid cam would operate smoothly at low, medium, and high frequencies of vibration and function properlyfor frequency and displacement of vibration up to 200 Hz and 20 mm respectivelywithout jamming and failing. A cycloid cam is therefore recommended for low,medium, and high frequencies motion of vibration

Collaboration of scientists from different countries is a crucial tool for the development of science. Today’s pandemic initiates the integration of the ideas of scientists around the world to study and combat the aggressive pathogen COVID-19. Under current circumstances, we are losing informal communication as one of the essential aspects of scientific progress. This situation seriously changes the paradigm of the development of scientific thought, reducing communication to formal things. Scientific discoveries occur just when thought goes beyond the framework. Thus, the pandemic poses a comprehensive threat to society. To date, the uncontrolled situation of the pandemic is associated with a multifaceted behavioral factor of the virus. The virus acts differently on different continents of the planet and within the same geographical area, which makes its symptoms somewhat arbitrary. This pushes to an entirely new, information-wave level of understanding of the virus. The penetration of virions into the cell is the transfer of information, in this case, foreign to it and damaging. The interaction of the “virtual signal” with the “information receiver” is evident, and the virion itself is considered a virtual genetic signal, which becomes real only when received by a cell with an adequate code. The nature of the information contained in viruses is essential for determining the formation of diseases. These may be purely functional disorders, inflammatory (regardless of their location), or other processes. All of the above is determined based on the vibration frequencies of the virus–organism system. Viruses, like other biological objects, are characterized by both systemic biological properties and purely physical ones. If we consider the human body from the standpoint of physical properties, there is no division between the body’s internal environment and the external one. There is a single environment engulfed in cyclic, oscillatory processes, the characteristics of which are the same everywhere: in a person, in the movement of planets, on the Sun, and in interplanetary space. Throughout evolutionary history, both the virus and the organism are formed based on mutual environmental fluctuations. The formation of a specific oscillatory system, based on general physical considerations, ends when the oscillations of all system components are coordinated with each other. Thus, having information about the vibration frequencies of viral fragments, we can artificially select such a protein, the vibration frequency of which corresponds to the rhythm of the virus fragment. Such a protein could bind to the virus, preventing it from infecting healthy cells.

Introduction. Add-on compactors for excavators (ACE hereinafter) are replaceable working equipment for excavators. They are used for soil compaction after the backfill of trenches, wells, foundation cavities and other “narrow spaces” of construction, as well as soil compaction at slopes of embankments and excavations.In practical use of ACE, builders face two challenges:to justify the choice of an ACE for soil compaction under given conditions determined by the soil type and moisture, layer thickness, and the required compaction factor; to determine the time required to compact soil with an ACE at a single point positional compaction to ensure the required compaction factor of a given type of soil in a layer of required thickness.The problems above require the information regarding technological capabilities of ACEs in different technological situations of soil compaction. The assessment of such technological capabilities of ACEs, at the same time, should take into account the ongoing transition to a new regulatory framework in Russia in the field of assessment indicators for the results of soil compaction in construction.Materials and methods. ACE technological capabilities review was conducted based on the information provided on the official websites of the largest Russian and foreign ACE manufacturers and suppliers.Conclusion. The analysis of information provided by ACE manufacturers and suppliers showed that most of that information is technical specifications of ACEs and excavators. There is almost no information on technological capabilities of ACEs. At the same time, ACE manufacturers and suppliers use ambiguous terminology (for example, “compaction volume”) in the assessment of technological capabilities.Practical value. Lack of information on technological capabilities of ACEs in various technological situations of soil compaction leads to errors in selection of an ACE model and its operation time during single point positional soil compaction, which increases the risk of under compaction and reduced service life of constructed objects. To solve this problem, the Construction and Road-Building Machinery Department of Yaroslavl State Technical University is developing a methodology for calculating the results of soil compaction with an ACE in different technological situations.

Perilous rock instability on the soil slope brings a substantial threat to project operation and even people’s lives. The buried depth of the perilous rock is a challenge to deal with and primarily determines its stability, and the indirect rapid identification of its buried depth is the key to its stability evaluation. The paper aims to find a new and quick method to measure the buried depth of perilous rock on the soil slope and to solve the hard-to-measure buried depth stability evaluation. When the damping ratio is less than one, and the deformation is linear elastic throughout the amplitude range, the potentially perilous rock vibration model may reduce to a multi-degree-of-freedom vibration one. By theoretical deduction, a quantitative relationship is established among the perilous rock mass, the basement response coefficient, the buried depth of the perilous rock, and the natural horizontal vibration frequency. In addition, the accuracy of this relationship is confirmed via numerous indoor experiments, showing that the horizontal vibration frequency of the perilous rock model in one dimension increases as the buried depth increases. Finally, based on the natural vibration frequency and guided by the limit balance model, a stability evaluation model of the perilous rock on the soil slope is constructed. Hence, the example shows that the method is feasible. The research findings are of vital significance for the stability evaluation of the perilous rock on the soil slope and give a novel approach and theoretical foundation for quick identification and monitoring.

In field harvesting conditions, the non-stationary random vibration characteristics of the harvester are rarely considered, and the results of vibration frequency calculated by different time–frequency transformation methods are different. In this paper, the harvester’s vibration characteristics under the time-varying mass were studied, and the correlation between vibration frequency and modal frequency was analyzed. Firstly, under the conditions of time-varying mass (field harvesting conditions) and non-time-varying mass (empty running condition), the non-stationarity characteristics of vibration signals at 16 measurement points of a combined corn harvester frame were studied. Then, fast Fourier transform (FFT), short-time Fourier transform (STFT), and continuous wavelet transform (CWT) were used to calculate the vibration frequency distribution characteristics of the corn harvester. Finally, based on the EFDD (enhanced frequency domain decomposition) algorithm, the correlation between the primary vibration frequency and the operating mode frequency is studied. The results show that the mean, variance, and maximum difference of the vibration amplitude under harvesting conditions (mass time-varying system) are 0.10, 26.5, and 1.0, respectively, at different harvesting periods (0~10 s, 10~20 s, 20~30 s). The harvesting conditions’ vibration signals conform to the characteristics of non-stationary randomness. The FFT algorithm is used to obtain more dense vibration frequencies, while the frequencies based on STFT and CWT algorithms are sparse. The correlation between the FFT method and the EFDD algorithm is 0.98, and the correlation between the STFT, CWT, and the EFDD algorithm is 0.99 and 0.98. Therefore, the primary frequency of the STFT methods is closer to the modal frequency. Our research laid the foundation for further study and application of mass time-varying combined harvester system non-stationary random vibration modal frequency identification and vibration control.

One of the best precursors for winter wheat is fallow. Its application aims to solve two important tasks: preserving and accumulating soil moisture and weed control. The authors of this paper have designed a new modular harrow for fallow tillage, which can work stably at a depth of 5–6 cm tillage while maintaining and even accumulating soil moisture. This article describes a method designed by the authors for a reasonable selection of the design parameters concerning the working devices mounted inside the new harrow, such as their length and working width, as well as the angles of vertical inclination (ε) and horizontal deviation (γ) of blades, depending on the accepted depth of the upper soil layer loosening. To reduce the soil tillage resistance of the harrowing unit resulting in a reduction in the tractor fuel consumption, the value of the inclination angle (ε) of its vertical blade should be chosen so that the corresponding change in the value of the deflection angle of the horizontal blade (γ) complies with the constrain of the product of tangents of these angles. Moreover, preference should be given to choosing the value of the angle ε with the subsequent determination of the angle γ value. It is demonstrated that proper use of the new type of harrow assures fuel savings and decreases carbon dioxide emissions even if fossil fuel alone is used. Additional reduction of CO2 emission can be achieved when biofuels are used as a replacement for fossil ones.

Extending the durability of functioning of the sensitive elements of radiation indicators and increasing their reliability and safety are the main requirements for producers of modern radiation reconnaissance and monitoring devices. The proposed solutions for construction improving of products provide for the usage of optical fibers and the corresponding formation of loop-shaped channels in the finished sensitive polymer element. Potential possibilities of using magnetic abrasive polishing for finishing channel surfaces are considered. For the chosen construction of the polishing head, the material and form of the powder particles composition and the process parameters are proposed. The effect of the frequency and amplitude of vibration of abrasive particles on the depth of their penetration into the surface layer of the polymer is investigated. It has been determined that the widest possibilities of using powders of the composition Fe - C - Si - Ti with a diameter of d = 50 – 400 μm have a mode when the pressure of the air flow by feeding particles is maintained at a level of 1 atm, the magnetic induction of the field in the working gap is 0.8 T, the vibration amplitude of the particles is a = 0.4 mm, and the vibration frequency varies in the range f = 25 – 30 Hz, Подовжити довговічність функціонування – головна вимога до виробників сучасних приладів радіаційної розвідки та контролю. Запропоновані рішення щодо вдосконалення конструкції виробів передбачають використання оптичних світловодів та відповідне формування канавок петлеподібного профілю у готовому чутливому полімерному елементі. Розглянуто потенційні можливості використання магнітно-абразивного полірування для фінішної обробки поверхонь канавки чутливих елементів дозиметрів з метою підвищення їх надійності та безпечності. Для вибраної конструкції полірувальної головки запропоновано матеріал та форму порошкової композиції і параметри процесу. Досліджено вплив частоти та амплітуди коливання часточок на глибину їх проникнення у поверхневий шар полімеру.

One of the main means of reducing aerodynamic noise is the use of silencers, which can be made of various porous materials, depending on the specific operating conditions. The aim of the work is to study the dependence of the noise reduction on the characteristics of porous permeable materials (PPM) obtained by vibration molding from metal powders. Such PPMs have a wide range of porosity, high permeability, mechanical strength, provide the ability to work in a wide temperature range, high corrosion resistance, and therefore find more and more widespread application in practice. When designing silencers, their pore size, permeability, mechanical strength, cost, and the chemical composition of the material are taken into account. Basic research methods – determination of noise level, powder particle size, permeability coefficient, pore size. Vibration molding of PPM samples for experimental studies was carried out on a ВЭДС 10-1А vibration bench with vibration parameters that ensured the maximum bulk density of the powder in the mold (acceleration 10 m/s2, frequency 500 Hz). Main results – the dependence of the noise reduction value on the PPM characteristics obtained by the method of vibration molding of metal powders of various grades of various particle size distribution was studied. It has been shown that the most effective damping is provided by PPM from spherical bronze powder of the БрОФ10-1 grade with particle sizes of 350–400 microns, which provides at the same time a combination of a high level of noise reduction and high permeability to air or gas. It was found that the thickness of the muff significantly affects the efficiency of noise suppression, while the minimum thickness of the muff, which provides a sufficiently high degree of noise reduction, is about 3.5 mm, therefore it is not practical to increase the thickness of the muffler material above this value.

The working process of concrete mixture compaction is investigated. The model of the processing medium is determined, which is characterized by three stages. At the first stage of compaction it is a free-flowing medium, at the second and third stages of compaction it is an elastic-viscoplastic medium. This result lies in the definition of the physical and mathematical model, the equations of motion. The vibration system «machine-medium» at any moment of movement consists of two components – one is capable of accumulating energy that passes from one form to another (reactance), and the second is energy dissipation (active resistance). The influence of active and reactive forces on the general movement of the system under study has been investigated and determined. By solving the equations, analytical dependencies were obtained, which established the laws of motion of the «Vibration machine – sealing medium» system. Practical implementation for technical systems for the formation of concrete products and soil compaction processes under the main pipeline has been carried out. An algorithm and method for calculating the main parameters of vibration systems for compaction of working media have been developed.

The studies carried out revealed the influence of the vibration frequency and the angle of inclination on the efficiency of sorting. It was found that with an increase in the vibration frequency and vibration amplitude of the box, the separation of the material and the sorting speed increase. The proposed model made it possible to determine the transport speed in the case when the sieve screen carries out a circulating movement, which is the application of two independent vibrations with different amplitudes and frequencies. The number of throws of the material to be sorted is influenced by the transport time of this material over the surface of the sieve and the amount of vibration excitation to this material. The dependence of the used power on the design and technological parameters of the vibration screen was revealed. An algorithm and method for calculating the main parameters of a vibration screen were developed.

Local vibration has shown promise in improving skin blood flow (SBF). However, there is no consensus on the selection of the best vibration frequency. An important reason may be that previous studies utilized time- and frequency-domain parameters to characterize vibration-induced SBF responses. These parameters are unable to characterize the structural features of the SBF response to local vibrations, thus contributing to the inconsistent findings seen in vibration research. The objective of this study was to provide evidence that nonlinear dynamics of SBF responses would be an important aspect for assessing the effect of local vibration on SBF. Local vibrations at 100 Hz, 35 Hz, and 0 Hz (sham vibration) with an amplitude of 1 mm were randomly applied to the right first metatarsal head of 12 healthy participants for 10 min. SBF at the same site was measured for 10 min before and after local vibration. The degree of regularity of SBF was quantified using a multiscale sample entropy algorithm. The results showed that 100 Hz vibration significantly increased multiscale regularity of SBF but 35 Hz and 0 Hz (sham vibration) did not. The significant increase of regularity of SBF after 100 Hz vibration was mainly attributed to increased regularity of SBF oscillations within the frequency interval at 0.0095&ndash, 0.15 Hz. These findings support the use of multiscale regularity to assess effectiveness of local vibration on improving skin blood flow.

Graphene is a type of two-dimensional material with special properties and complex mechanical behavior. In the process of growth or processing, graphene inevitably has various defects, which greatly influence the mechanical properties of graphene. In this paper, the mechanical properties of ideal monolayer graphene nanoribbons and monolayer graphene nanoribbons with vacancy defects were simulated using the molecular dynamics method. The effect of different defect concentrations and defect positions on the vibration frequency of nanoribbons was investigated, respectively. The results show that the vacancy defect decreases the vibration frequency of the graphene nanoribbon. The vacancy concentration and vacancy position have a certain effect on the vibration frequency of graphene nanoribbons. The vibration frequency not only decreases significantly with the increase of nanoribbon length but also with the increase of vacancy concentration. As the vacancy concentration is constant, the vacancy position has a certain effect on the vibration frequency of graphene nanoribbons. For nanoribbons with similar dispersed vacancy, the trend of vibration frequency variation is similar.

A considerable number of studies for vortex induced vibration (VIV) under uniform flow have been performed. However, investigation of VIV under middle flow is scarce. An experiment for VIV under middle flow was conducted in a deep-water offshore basin. Various measurements were obtained by the fiber Bragg grating strain sensors placed on the riser, and VIV under the effect of middle flow with was investigated. Results show that the riser vibrates at different order natural frequencies along the water depth in the CF and IL directions appearing as the multi-frequencies under middle flow. The variation vortex shedding frequencies along the riser under middle flow may generate different wake modes and vibration modals as the corresponding vortex shedding frequencies approach the riser natural frequencies. The dominant vibration frequency of the entire riser is consistent, and determined by high order natural frequency and the corresponding closing vortex shedding frequencies under the middle flow. Meanwhile, the vibration modal under middle flow appears multi-modals and other lower modal have effect on riser vibration. The VIV mechanism under middle flow possesses some aspects similar to those of uniform flow and several unique features.

On the base of the analysis of the application of vibration mechanisms in the motor transport vehicles, considering the possibilities of fuel injection systems, the study presents survey of possibilities the usage of the devices micro-dosing and spraying apparatus, the construction and the principle of the operation of vibration-assisted spring-loaded batcher, the necessary for its functioning vibration operation forms and the dependences of measured fuel amount on the leakage chamber width and how it is related to vibration frequency and amplitude. The results of mathematical modeling and experimental analysis based on laser holographic interferometry are presented.

Ячиков Игорь Михайлович, д-р техн. наук, профессор, профессор кафедры вычислительной техники и программирования, Магнитогорский государственный технический университет им. Г.И. Носова, г. Магнитогорск; jachikov@mail.ru. Ширяев Владимир Иванович, д-р техн. наук, профессор, заведующий кафедрой систем автоматического управления, Южно-Уральский государственный университет, г. Челябинск; shiriaevvi@susu.ru. I.M. Yachikov1, jachikov@mail.ru, V.I. Shiryaev2, shiriaevvi@susu.ru 1Nosov Magnitogorsk State Technical University, Magnitogorsk, Russian Federation 2South Ural state University, Chelyabinsk, Russian Federation Введение. Существуют различные практические способы реализации магнитной левитации как метода удержания или подъема объекта с помощью одного только магнитного поля. В работе рассматривается следующий принцип создания равновесия тела. Небольшой цилиндрический неодимовый магнит удерживается при электромагнитном взаимодействии с пульсирующим током, протекающим через катушку. Для возникновения парящего эффекта при приближении магнита к катушке ток через нее отключается электронным ключом, срабатывающим от цифрового датчика Холла, расположенного на оси катушки. Вызывает практический интерес разработка простых рекомендаций, позволяющих прогнозировать факт удержания тела при данной конструкции катушки, токе через нее, размерах и свойствах постоянного магнита. Мало инженерных методик, позволяющих определять положение тела, его устойчивость и характер движения во взвешенном состоянии. Целью исследования является теоретическое и экспериментальное исследование динамических параметров постоянного магнита при его удержании в импульсном магнитном поле и создание упрощенной расчетно-экспериментальной методики для определения характеристик поведения тела во взвешенном состоянии. Материалы и методы. При выполнении работы применялись методы математического и компьютерного моделирования, а также экспериментального исследования. Созданное программное обеспечение с использованием средств разработки пакета Mathcad основывалось на известных методах численного интегрирования системы дифференциальных уравнений. Результаты. Предложена упрощенная расчетно-экспериментальная методика по определению магнитных моментов для постоянного цилиндрического магнита и катушки с током, а также примерного значения координаты положения тела во взвешенном состоянии. Разработана математическая модель одномерного движения магнита под действием силы тяжести и электромагнитной силы взаимодействия с импульсным магнитным полем при известном расстоянии, на котором происходит выключение тока. Заключение. Экспериментально и посредством компьютерного моделирования установлено, что чем выше частота пульсаций, тем при удержании тела наблюдается его меньшая амплитуда пульсаций и устанавливается более устойчивое равновесие. Частота пульсаций уменьшается с увеличением массы постоянного магнита, причем есть критическая масса, которая уже не удерживается в электромагнитном поле. При увеличении напряжения, подаваемого на коммутатор катушки, возрастает частота пульсаций тела и потребляемая электрическая мощность, при этом коэффициент заполнения импульсов тока снижается. Introduction. There are various practical ways to implement magnetic levitation as a method of holding or lifting an object using a magnetic field alone. The following principle of creating the balance of the body is considered in the work. A small cylindrical neodymium magnet is held during electromagnetic interaction with a pulsating current flowing through the coil. For a soaring effect to occur when the magnet approaches the coil, the current through it is switched off by an electronic key that is activated by a digital Hall sensor located on the axis of the coil. Of practical interest is the development of simple recommendations to predict the fact of body retention with a given coil design, current through it, dimensions and properties of a permanent magnet. There are few engineering techniques to determine the position of the body, its stability and the nature of movement in suspension. The aim of the study is a theoretical and experimental study of the dynamic parameters of a permanent magnet when it is held in a pulsed magnetic field and the creation of a simplified computational- experimental technique for determining the characteristics of the body in suspension. Materials and methods. When performing the work, methods of mathematical and computer modeling were used, as well as experimental studies. The created software using the development tools of the Mathcad package was based on well-known methods: numerical integration of a system of differential equations. Results. A simplified computational and experimental technique is proposed for determining magnetic moments for a permanent cylindrical magnet and coil with current, as well as an approximate value of the coordinate of the position of the body in suspension. A mathematical model of the onedimensional motion of a magnet under the influence of gravity and electromagnetic forces of interaction with a pulsed magnetic field at a known distance at which the current is turned off is developed. Conclusion. It was established experimentally and through computer simulation that the higher the frequency of the pulsations, the more rigid the pulsation amplitude is observed when the body is held and a more stable equilibrium is established. The ripple frequency decreases with increasing mass of the permanent magnet, and there is a critical mass that is no longer held in the electromagnetic field. As the voltage supplied to the coil switch increases, the frequency of the pulsations of the body and the consumed electric power increase, while the duty cycle of the current pulses decreases.

The monograph is devoted to the development of mechanical systems with dynamic effects on processing media. A new approach and methodology is proposed, taking into account the influence of energy fields of physical and me-chanical effects, the transformation and inversion of types of energy exposure. The model of dispersed media under consideration in the range of the process of destruction, grinding and compaction is considered. The revealed changes in the parameters of subsystems: working media, mechanical systems, the process-es of their interaction are studied based on the consideration of their stress-strain state. The analysis of combinations and their influence on the intensity of phy-sical and mechanical processes is carried out. The intensification of physical and mechanical processes, methods and means of their creation are achieved by the formulated idea: systematization and complexity of approaches through a joint consideration of the mutual influence of the internal properties of the subsys-tems made it possible to identify the general laws of their changes and take them into account in the work process. The movement of the working media during high-speed and impact destruction with differentiation of the working area is de-scribed. Structuring of the shock process, the formation of entropy destruction, the use of self-organization and the evolution of geometric shapes are evaluated. The process of grinding materials by a vibratory jaw crusher is investigated and methods for determining the effective parameters and their operation modes are proposed. The process of compaction of the processing medium in the field of vibrations in the device with spatial vibrations is described. The laws of change in the device movement, taking into account interaction with the processing medium are established. As a research result, new properties of the behavior of discrete-continuous systems under power load are disclosed. For the first time, stresses and strains are taken into account as working bodies and media for creating energy-saving vibration systems for compaction of building materials. The conducted scientific study makes it possible to obtain the laws of change in the state of dispersed media under the action of power loads by mechanical sys-tems. Minimization of energy costs and increase the efficiency of work processes is proposed when implementing various technological processes.

Focal vibration therapy can provide neurophysiological benefits. Unfortunately, standardized protocols are non-existent. Previous research presents a wide range of protocols with a wide range of effectiveness. This paper is part of a broader effort to identify effective, standardized protocols for focal vibration therapy. In this study, the authors evaluated the vibration characteristics (frequency and peak-to-peak intensity) of four commercially available focal vibration devices: (1) Vibracool (wearable), (2) Novafon (hand-held), (3) Myovolt 3-actuator (wearable), and (4) Myovolt 2-actuator (wearable). An accelerometer was used for the measurements. Measurements were made under the following two conditions: (a) when the devices were free, i.e., unconstrained vibration, and (b) when the devices were strapped to the human body, i.e., constrained vibration. In the free vibration condition, frequency ranged from 120 to 225 Hz and peak-to-peak amplitude ranged from 2.0 to 7.9 g’s. When the devices were strapped to the body (constrained), vibration amplitude decreased by up to 65.7%. These results identify effective ranges of focal vibration frequency and amplitude. They illustrate the importance of identifying vibration environment, free or constrained, when quoting vibration characteristics. Finally, the inconsistency output of multi-actuator devices is discussed. These results will guide protocol development for focal vibration and potentially better focal vibration devices.

In the present research, high chromium cast irons (HCCIs) were prepared using the lost foam casting (LFC) process. To improve the wear resistance of the high chromium cast irons (HCCIs), mechanical vibration was employed during the solidification of the HCCIs. The effects of vibration frequency on the microstructure and performance of the HCCIs under as-cast, as-quenched and as-tempered conditions were investigated. The results indicated that the microstructures of the LFC-produced HCCIs were refined due to the introduction of mechanical vibration, and the hardness was improved compared to that of the alloy without vibration. However, only a slight improvement in hardness was found in spite of the increase of vibration frequency. In contrast, the impact toughness of the as-tempered HCCIs increased with an increase in the vibration frequency. In addition, the wear resistance of the HCCIs was improved as a result of the introduction of vibration and increased with an increase in the vibration frequency.

In order to study the effect of the operational loads on the ground-borne vibration of the high-speed train, a train-track coupling model with considering the vertical and horizontal effects is established and applied to calculate the impact of different operational speeds on vibration acceleration. As shown in the results, the vibration acceleration is largely affected by different frequencies generated from different train speeds. By means of an indoor dynamic triaxial test, the impact of different vibration frequencies of a train on soil body is simulated. And a large number of medium- and low-frequency vibration tests are conducted according to the settings of load form, drainage requirement and vibration number of train vibration loads. The experimental results are analyzed to study the effect of different frequencies on dynamic characteristics, and a dynamic strain-time calculation formula, that takes the frequency factor into consideration, is proposed. Meanwhile, the improved formula that considered frequency is substituted into the finite element model (FEM) of the train, so as to analyze the impact of different vibration frequencies on the settlement, is applied. As shown in the results, the proposed improved formula, that considered the frequency, is good at prediction. The effect of vibration efficiency on the engineering can be reflected by a simulated high-speed train model. Based on the simulation model, a reinforcement measure is conducted for the ground-borne, and it is calculated that the settlement is obviously reduced and the service time of the train ground-borne is increased. This paper can provide a reference for a theoretical research and engineering practice.

The scheme of statically definable truss of spatial coverage is proposed. The formula for the dependence of the vibration frequency on the number of panels is derived. The Dunkerley lower bound and the induction method are used to generalize particular solutions to the case of an arbitrary number of panels. The calculation of the forces in the rods by cutting out the nodes and the analytical transformations to obtain the desired dependence are performed in the Maple computer mathematics system. The solution is compared with the numerical one obtained by solving the problem on the eigenvalues of the characteristic matrix for a system with many degrees of freedom. It is shown that the estimation accuracy depends on the number of panels.

In this review, we present a narrative synthesis of studies on the use of focal muscle vibration (FMV) in stroke rehabilitation with a focus on vibration device, parameters, and protocols. A search was conducted via PubMed, SCOPUS, PEDro, REHABDATA, and Web of Science using the keywords “stroke and focal vibration” or “focal muscle vibration”. Inclusion and exclusion criteria to select the articles were determined. Twenty-two articles involving FMV and stroke were included in this review. Eight different vibration devices were used in the 19 articles that reported the vibration apparatuses. The vibration frequencies ranged from 30 Hz to 300 Hz with amplitudes ranging from 0.01 mm to 2 mm. The vibration treatment frequency ranged from a single treatment to 5 days/week. The session duration ranged from 14 s to 60 min/session with a duration of a single treatment to eight weeks. Twenty different muscles were targeted with 37 different outcome measures used to assess the effects of FMV. The clinical applications of FMV were not confirmed based on available evidence. More research is needed to improve the FMV technology, guide the selection of vibration parameters, optimize the vibration dosage, and develop standardized protocols for FMV therapy in patients with stroke.

The technique of vibration-induced illusory movement has been used to study the mechanisms of perception and the brain network responsible for eliciting kinesthesia since it was first reported by Goodwin and colleagues in 1972. Vibration applied to the skin surface over the tendon of limb muscles excites primary afferent spindles, and subjects experience movement sensations as if the vibrated muscle were stretched, despite the limb being immobile. In addition, tendon vibration can induce tonic muscle activities in both the vibrated muscle and its antagonistic muscles. It was formerly believed that these motor responses accompanied the kinesthetic illusion of the vibrated limb. However, if subjects relax their limb completely and focus their attention on the movement sensed during vibration, a movement illusion can be elicited without any motor responses. This review focuses on the relationship between the elicitation of vibration-induced kinesthetic illusions and experimental conditions, and may provide insight into differences among studies of kinesthetic illusion.

The paper presents the results of experimental research conducted on the newly constructed post-tensioned pre-stressed concrete road bridge situated over water plant of water reservoir under dynamic field load tests in Topola village (Poland). The dynamic loads consist of four heavy trucks passing at different speeds, through threshold and braking at the midspan. The obtained results from field load tests and the calculation of dynamic coefficients, values of amplitudes of vibration velocities and frequencies of two bridge spans have allowed to assessment of effectiveness of structural solutions applied at this bridge and establish some guidelines for using of this type of construction process in design structural solutions located over water plants in the future engineering practice. Wide range of conducted dynamic tests have allowed for comprehensive evaluation of the concrete elements effort of bridge structure. Final conclusions confirmed the observations taken from the research under static load.

The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D vibration frequencies, the mobility of H+/D+ carriers, the kinetics of the electrochemical oxidation of H2/D2, the solubilities of H2O/D2O and, finally, the spontaneous electromotive force that appears across H2/D2 cells with proton conducting electrolytes. Comparable work on tritium-exchanged materials is also discussed. The results highlight the usefulness of isotope effects in the study of high temperature proton conductors.

The most important thing in a thin and soft haptic module with an electroactive polymer actuator array is to increase its vibrotactile amplitude and to create a variety of vibrotactile sensations. In this paper, we introduce a thin film-type electroactive polymer actuator array capable of stimulating two types of human mechanoreceptors simultaneously, and we present a haptic rendering method that maximizes the actuators&rsquo, vibrational force without improving the array&rsquo, s haptic performance. The increase in vibrational amplitude of the soft electroactive polymer actuator array is achieved by creating a beat vibration, which is an interference pattern of two vibrations with slightly different frequencies. The textures of a target object are translated into haptic stimuli using the proposed method. We conducted qualitative and quantitative experiments to evaluate the performance of the proposed rendering method. The results showed that this method not only amplifies the vibration&rsquo, s amplitude but also haptically simulates various objects&rsquo, surfaces.

Sonic drill rig can obtain good drilling and sampling effects in sand gravel layer with high-frequency vibration and low speed rotation of the power head. The drilling speed of sonic drill is five times than traditional rotary drilling method. Meanwhile, it does not need slurry to protect wall of borehole during drilling, so it has the following advantages: good fidelity of rock and soil samples and less environmental pollution. As a consequence, it has a good application prospect in the exploration of hydropower station, environmental protection drilling and other fields. In the paper, combining drilling experiment of domestic sonic drill rig YGL-S100 in Xiangjiaba hydropower station, the influence of sonic drill's vibration frequency on rock fragmentation effect and the reasonable choice of drilling technology had been researched and analyzed. Further, improving the sonic drill properties and optimizing drilling technology parameter were carried out.

© 2017 Springer Science+Business Media, LLC A discrete layered damping model of a multilayer plate at small displacements and deformations, with account of the internal damping of layers according to the Thompson–Kelvin–Voight model, is presented. Based on the equations derived, an analytical solution to the static deformation problem for single-layer rectangular plate hinge-supported along its contour and subjected of a uniformly distributed pressure applied to one of its boundary planes is obtained. Its convergence to the three-dimensional solution is analyzed in relation to the dimension of mesh in the thickness direction of the plate. It is found that, for thin plates, the dimension of the problem formulated can be reduced on the basis of simplified hypotheses applied to each layer. Аn analytical solutions is also constructed for the forced vibrations of two- and three-layer rectangular plates hinged in the opening of an absolutely stiff dividing wall upon transmission of a monoharmonic sound wave through them. It was assumed that the dividing wall is situated between two absolutely stiff barriers; one of them, owing to the harmonic vibration with a given displacement amplitude of the plate, forms an incident sound wave, and the other is stationary and is coated by a energy-absorbing material with high damping properties. Behavior of the acoustic media in spaces between the deformable plate and the barriers is described by the classical wave equations based on the model of an ideal compressible fluid. To describe the process of dynamic deformation of the energy-absorbing coating of the fixed barrier, two-dimensional equations of motion are derived based on the model of a transversely soft layer, a linear approximation of displacement fields in the thickness direction of the coating, and the account of damping properties of its material by using the hysteresis model. The effect of physical and mechanical parameters of the mechanical system considered and of frequency of the incident sound wave on the parameter of its sound insulation, and the characteristics of stress-strain state of the plate is investigated

In this report, we present the research results on using the conventional method and microwave technology to extract curcuminoid from turmeric roots originated in different regions of Northern Vietnam. This method is simple, yet economical, non-toxic and still able to achieve high extraction performance to get curcuminoid from turmeric roots. The detailed results on the Raman vibration spectra combined with X-ray powder diffraction and high-performance liquid chromatography/mass spectrometry allowed the evaluation of each batch of curcumin crystalline powder sample received, under the conditions of applied fabrication technology. Also, the absorption and fluorescence spectroscopies of the samples are presented in the paper. The information to be presented in this paper: absorption and fluorescence spectroscopies of the samples; new experimental study results on applied technology to mass-produce curcumin from turmeric rhizomes; comparative study results between fabricated samples and marketing curcumin products-to state the complexity of co-existing crystalline phase in curcumin powder samples. We noticed that, it is possible to use the vibration line at ~959 cm(-1)-characteristic of the ν C=O vibration, and the ~1625 cm(-1) line-characteristic of the ν C=O and ν C=C vibration in curcumin molecules, for preliminary quality assessment of naturally originated curcumin crystalline powder samples. Data on these new optical spectra will contribute to the bringing of detailed information on natural curcumin in Vietnam, serving research purposes and applications of natural curcumin powder and nanocurcumin in Vietnam, as well as being initial materials for the pharmaceutical, cosmetics or functional food industries.

In this paper, we propose a new ultra-high-precision magnetic abrasive finishing method for wire material which is considered to be difficult with the existing finishing process. The processing method uses a rotating magnetic field system with unbonded magnetic abrasive type. It is believed that this process can efficiently perform the ultra-high-precision finishing for producing a smooth surface finish and removing a diameter of wire material. For such a processing improvement, the following parameters are considered, rotational speed of rotating magnetic field, vibration frequency of wire material, and unbonded magnetic abrasive grain size. In order to evaluate the performance of the new finishing process for the wire material, the American Iron and Steel Institute (AISI) 1085 steel wire was used as the wire workpiece. The experimental results showed that the original surface roughness of AISI 1085 steel wire was enhanced from 0.25 &micro, m to 0.02 &micro, m for 60 s at 800 rpm of rotational speed. Also, the performance of the removed diameter was excellent. As the result, a new ultra-high-precision magnetic abrasive finishing using a rotating magnetic field with unbonded magnetic abrasive type could be successfully adopted for improving the surface roughness and removing the diameter of AISI 1085 steel wire material.

The paper presents the construction of vibration -assisted spring-loaded batcher, its principle of operation is described, the spring-loaded batcher transverse vibration forms and the dependence of the vibration frequency and the amplitude on the dosed liquid are introduced. Mathematical modelling and the experimental results are presented in the paper. DOI: http://dx.doi.org/10.5755/j01.mech.21.4.9977

OBJECTIVES—To investigate the acute effects of the frequency of hand transmitted vibration on finger circulation. A further aim was to investigate whether the frequency weighting assumed in current standards for hand transmitted vibration reflects the haemodynamic changes which occur in the fingers exposed to vibration with different frequencies but with the same frequency weighted acceleration magnitude. METHODS—Finger skin temperature (FST) and finger blood flow (FBF) were measured in the middle fingers of both hands of 10 healthy men. With a static load of 10 N, the right hand was exposed for 15 minutes to the following root mean square (rms) acceleration magnitudes and frequencies of vertical vibration: 5.5 m/s2 at 16 Hz; 11 m/s2 at 31.5 Hz; 22 m/s2 at 63 Hz; 44 m/s2 at 125 Hz; and 88 m/s2 at 250 Hz. These exposures to vibration produce the same frequency weighted acceleration magnitude (5.5 m/s2 rms) according to the frequency weighting included in the international standard ISO 5349. A control condition consisted of exposure to the static load only. Finger circulation was measured before application of the vibration and static load and at fixed intervals during exposure to vibration and a 45 minute recovery period. RESULTS—No significant changes in finger circulation were found with only the static load. The FST did not change significantly during or after acute exposure to vibration. In the vibrated right finger, exposures to vibration with frequencies of 31.5-250 Hz provoked a greater reduction in FBF than did vibration of 16 Hz or the static load only. In the non-vibrated left finger, the FBF measured with vibration at each frequency of 63-250 Hz was significantly lower than that measured with static load only. The reduction in FBF during exposure to vibration with any frequency was stronger in the vibrated finger than in the non-vibrated finger. In both fingers, there was a progressive decrease in FBF after the end of exposure to vibration with frequencies of 31.5-250 Hz. The higher the frequency of vibration, the stronger the decrease in FBF in both fingers during recovery. CONCLUSIONS—Acute exposures to vibration with equal frequency weighted magnitude reduce the FBF in both vibrated and non-vibrated fingers for frequencies between 31.5 and 250 Hz. The extent of digital vasoconstriction after exposure to vibration increases with increasing frequency. The frequency weighting given in current standards tends to overestimate the vasoconstriction associated with acute exposures to vibration frequencies around 16 Hz. Keywords: finger circulation; frequency weighted acceleration magnitude; vibration frequency

The aim of this study is to highlight the relation between muscle motion and electromyographyc activity during whole body vibration. This treatment is accounted for eliciting a reflex muscle activity in response to vibratory stimulation. Simultaneous recordings from quadriceps Rectus Femoris EMG and 3D muscle accelerations on fifteen subjects undergoing vibration treatments were collected. In our study vibrations were delivered via a sinusoidal oscillating platform at different frequencies (10-45 Hz), with a constant amplitude. Muscle motion was estimated by processing accelerometer data. Displacements revealed a mechanical resonant-like behaviour of the muscle; resonance frequencies and dumping factors depended on subject. Large EMG motion artifacts were removed using sharp notch filters centred at the vibration frequency and its superior harmonics. RMS values of artifact-free EMG were found correlated to the actual muscle displacement. The results were in accordance to the hypothesis of a proprioceptive response during vibration treatment. Nevertheless, motion artifacts produced an overestimation of muscle activity, therefore its removal was essential. © 2009 Springer Berlin Heidelberg.

Adaptive composites have been produced by embedding prestrained shape memory alloy (SMA) wires into an epoxy matrix, reinforced with aramid fibers. These materials demonstrate attractive effects such as shape change or a shift in the vibration frequency upon activation. When heated above their transformation temperature, the wires' strain recovery is confined, and recovery stresses are generated. As a result, if the wires are placed along the neutral axis of a composite beam, a shift in resonance vibration frequency can be observed. To optimize the design of such composites, the matrix - SMA wire interfacial shear strength has been analyzed with the pull out testing technique. It is shown that the nature of the wire surface influences the interfacial shear strength, and that satisfactory results are obtained for SMA wires with a thin oxide layer. Composite samples consisting of two different types of pre- strained NiTiCu wires embedded in either pure epoxy matrix or Kevlar-epoxy matrix were produced. The recovery force and vibration response of composites were measured in a clamped-clamped configuration, to assess the effect of wire type and volume fraction. The results are highly reproducible in all cases with a narrow hysteresis loop, which makes NiTiCu wires good candidates for adaptive composites. The recovery forces increase with the volume fraction of the embedded wires, are higher when the wires are embedded in a low CTE matrix and, at a given temperature, are higher when the wire transformation temperature is lower.

This paper pursues the effect of changes in distance and vibration frequency on the vibration velocity amplitude. As an example, we used the vibrating sheet piles at the construction of a new multi-functional FEI building on the premises of VŠB - TU Ostrava, at 17 listopadu street. The effect of these changes is monitored both in in-situ measurements and in a simulated real-life situation. The calculation software Plaxis 2D is used for creation of numerical models. At the close, the results from in-situ measurements are confronted with those achieved from the models. Web of Science 9 2 171 165