Search

Despite the recognized influence of body mass on combat techniques, the relationship between body segment mass (BSM) and combat moves remains unexplored. This study aimed to examine the relationship between the striking arm mass (SAM), kicking leg mass (KLM), and body mass (BM) and the dynamic forces of direct punch (DP), palm strike (PS), elbow strike (ES), front kick (FK), and countermovement jump (CMJ) performance. Sixteen male military cadets (22.3 ± 1.8 years, 181.4 ± 7.0 cm, 82.1 ± 8.5 kg) performed combat techniques, with their performance measured by using a force plate and their body segment mass assessed by dual-energy X-ray absorptiometry. Spearman's correlation analysis, the Wilcoxon test, and Cohen's d were applied. The results indicated the relationship between the KLM or BM and the FK impulse (r = 0.64, p = 0.01; r = 0.52, p = 0.04, respectively) and CMJ impact force (r = 0.80, p ≤ 0.01; r = 0.70, p ≤ 0.01, respectively). The FK peak and impact forces were moderately correlated with the CMJ jump height (r = 0.74, p ≤ 0.01; r = 0.77, p ≤ 0.01). Moreover, the FK peak force was significantly higher than that for DP, PS, and ES (p ≤ 0.01, d = 3.32; p ≤ 0.01, d = 1.6; and p = 0.013, d = 1.3, respectively). The highest relationship was found between the KLM and the FK impulse; however, the difference in variability explained by the KLM versus the body mass was only 12%. This suggests that knowledge of the BSM did not provide a significantly better estimate of the dynamic forces of the punches and FKs than the knowledge of the BM. [ABSTRACT FROM AUTHOR]

One of the peculiarities for switch operation is the increased level of force interaction between the bearing elements of the switch and the rolling stock chassis, which causes increased requirements for strength, stability, reliability and durability of switches. Accordingly, to assess the strength of structures, it is necessary to know the magnitude of the forces acting on them, which can be determined experimentally or by theoretical calculations. In the case of tunnel sections of subways, experimental studies are extremely difficult to organize and conduct, so only theoretical methods are an alternative. This study presents the results of theoretical calculations of the elastic-dynamic characteristics for railway switches used in tunnel sections of subways. Practical calculations of the stiffness of rail threads and the modulus of elasticity of the sub-rail base were performed, and dependencies of the distribution of elastic-dynamic parameters along the length of railway switches were obtained. On their basis, the forces of interaction with the subway rolling stock were determined and their distribution along the length of the railway switch was analyzed. The obtained data can serve as a prerequisite for checking the strength of structural elements.

The dynamic forces generated between the tractors' tyres and soil are very difficult to carry out experimentally. These dynamic forces have an important role in the analysis of the tractor stability moving over the soil surface. The main aim of this article is to predict the three directions of dynamic forces between the lugged tyre and the soil. A theoretical study of tractor stability based upon the non-linear equations mathematical model of the whole tractor subject to road surface input in the time domain is presented. Pull, lift, and lateral forces between the tyres and soil are predicted. The investigation includes a study of the effect of lug height, lug angle, and slip ratio to improve tractor stability. Also, three types of common soil namely; sand, silt, and clay are used to evaluate their effect on lug dynamic forces in three directions. Most of the parameters of each soil are measured in the soil laboratory and fed to the mathematical model. The results showed that the lug tyre characteristics have a good influence on tractor stability. The sand soil has a larger effect on the dynamic forces than the clay soil. Box-Behnken design (BBD) is used to estimate the effectiveness of lug height, lug angle, slip ratio, and types of soil on the lift force. The results show the lift force decreases with the increase both of the lug height and lug angle. Furthermore, the estimated regression equation is obtained to evaluate the influence of different factors on lug dynamic forces. [ABSTRACT FROM AUTHOR]

Despite the recognized influence of body mass on combat techniques, the relationship between body segment mass (BSM) and combat moves remains unexplored. This study aimed to examine the relationship between the striking arm mass (SAM), kicking leg mass (KLM), and body mass (BM) and the dynamic forces of direct punch (DP), palm strike (PS), elbow strike (ES), front kick (FK), and countermovement jump (CMJ) performance. Sixteen male military cadets (22.3 ± 1.8 years, 181.4 ± 7.0 cm, 82.1 ± 8.5 kg) performed combat techniques, with their performance measured by using a force plate and their body segment mass assessed by dual-energy X-ray absorptiometry. Spearman’s correlation analysis, the Wilcoxon test, and Cohen’s d were applied. The results indicated the relationship between the KLM or BM and the FK impulse (r = 0.64, p = 0.01; r = 0.52, p = 0.04, respectively) and CMJ impact force (r = 0.80, p ≤ 0.01; r = 0.70, p ≤ 0.01, respectively). The FK peak and impact forces were moderately correlated with the CMJ jump height (r = 0.74, p ≤ 0.01; r = 0.77, p ≤ 0.01). Moreover, the FK peak force was significantly higher than that for DP, PS, and ES (p ≤ 0.01, d = 3.32; p ≤ 0.01, d = 1.6; and p = 0.013, d = 1.3, respectively). The highest relationship was found between the KLM and the FK impulse; however, the difference in variability explained by the KLM versus the body mass was only 12%. This suggests that knowledge of the BSM did not provide a significantly better estimate of the dynamic forces of the punches and FKs than the knowledge of the BM.

A description is given of the causes by which the transmission of vibration and airborne noise from equipment to the environment should be controlled. The paths of this transmission and applicable ways for its reduction by passive and active methods are examined. It has been demonstrated that pipelines, even vibration-isolated from the equipment by means of expansion joints, can transmit and even amplify vibration from the installation in a wide frequency range. It is noted that reducing the vibration of pipelines is important for effective vibration isolation of equipment in power and transport machine building, shipbuilding, and of oil and gas pipelines at pump stations. Effective control of the vibration and noise transmission to the environment has been shown to require a preliminary comprehensive analysis of the importance of all paths of their transmission. A description is given of a dedicated universal research test facility for a comprehensive study of the possibility and methods for reducing the transmission of vibration and airborne noise from operating equipment with a flow of working fluid through piping using passive and active methods. [ABSTRACT FROM AUTHOR]

This research aims to evaluate the effect of surface texturing on the cylinder liner on tribological characteristics such as minimum oil film thickness, power losses, and dynamic forces (asperity contact force, hydrodynamic force, and total friction force). The research covers the study of two lubrication conditions: (a) starved and (b) fully flooded. The surface texturing on the cylinder liner was produced by dimpling. For the development of the study, a numerical model was used with MATLAB® software. The analysis of the dynamic forces demonstrated that dimples in the cylinder liner led to a 10.10% decrease in the asperity contact force between the piston ring and the cylinder liner. On the other hand, surface texturing allows a 4.32% increase in the minimum oil film thickness, which results in a 6.05% decrease in power loss. The surface texturing improves the engine's energy efficiency by 3.11%. The fully flooded lubrication condition leads to higher estimates of the frictional force present in the combustion chamber. In general, the mathematical model allows estimating the tribological behavior between the compression ring and the cylinder liner, which is a useful tool for evaluating strategies to minimize the power lost due to surface friction. [ABSTRACT FROM AUTHOR]

The increase in the levels of short-circuit currents in the power system of the Republic of Belarus requires the study of the parameters of the electrodynamic stability of the main structural elements of electrical installations with flexible conductors. In case of a short circuit in the network, currents tenfold exceeding the rated one hundreds of times can flow through the current-carrying part of the device. When the magnetic fields formed by these currents interact, significant electromagnetic forces arise, which have a destructive effect both on the current-carrying parts themselves and on the structural elements of electrical installations, viz. support insulators, switching devices, measuring equipment. The movement of the wires in a short-circuit mode leads to the appearance of significant dynamic loads in them, which, in turn, are transmitted to the portals, support insulators and electrical devices. A topical problem is the occurrence of unacceptable mechanical forces in the main structural elements that can cause their destruction. Thus, the analysis of the physical and mechanical parameters and geometric dimensions of the flexible busbar of switchgear shows that a violation of the condition of electrodynamic resistance to tension is unlikely due to the high mechanical strength of the large-section steel-aluminum wires used. At the same time, span-limiting portals, support insulators and other electrical devices have significantly lower permissible bending loads. When exposed to dynamic forces, the conductors bend and transfer the load to the structural elements which have certain elasticity. Thus, a reliable determination of dynamic loads, taking into account the current-carrying parts acting on the supporting structures, is possible only if a dynamic task is set. The article describes the methods of mathematical modeling and computational experiment for analyzing the parameters of the electro-dynamic stability of the main structural elements which are determined using coefficients that depend on the natural frequencies of oscillations and the nature of changes in dynamic forces over time. To solve these problems, mathematical models are compiled and boundary value problems are formulated for calculating the electrodynamic stability of structural elements, taking into account the possible coincidence of the frequencies of natural and forced oscillations of structural elements taking into account the probable coincidence of the frequencies of forced and natural vibrations of structural elements.

Background: High-contact ratio gears are very important components for power transmission systems as they increase the load-carrying capacity of the gear wheel as well as reduce the dynamic loads and accordingly low vibration and noise. However, it has been observed that there are very few studies in the literature investigating the dynamic performance of high-contact spur gears at different operating speeds and calculating tooth root stress. Purpose: The main purpose of this study is to investigate the dynamic responses of high-contact spur gears at different operating speeds and the resulting in their bending durabilities. Another purpose of this study is to examine the performance of high-contact spur gears at different speeds compared to low-contact spur gears. Methods: Within the scope of the study, first, time-varying mesh stiffness of low- and high-contact ratio spur gears was calculated numerically. Dynamic models of gears with lumped parameters were obtained with the help of developed MATLAB programs. Structural analyses were performed with the obtained time-varying mesh stiffness and dynamic forces, and the bending strength performances of low- and high-clutch spur gears were compared. Results: As a result of the analysis, it has been observed that spur gears with high-contact ratio are exposed to approximately 40% lower dynamic forces than spur gears with low-contact ratios. In addition, due to the double–triple contact behavior, it has been observed that spur gears with high-contact ratio have about twice the load-carrying capacity of spur gears with a low-contact ratio. Conclusion: The results obtained in the study showed that high-contact ratio spur gears would be highly efficient in applications requiring high load-carrying capacity. The high-contact ratio spur gears have low operating vibration, noise, and dynamic transmission error when compared to the low-contact spur gears. [ABSTRACT FROM AUTHOR]

The dynamic wheel-rail contact forces resulting from the interaction between vehicle and track are responsible for the local track settlement. If these local settlements vary along the track, geometric irregularities develop further amplifying the dynamic loading of the track caused by the interaction between the vehicle and track. In this work, an efficient vehicle-track interaction (VTI) model is presented for predicting the long-term evolution of vertical track settlement during operation. The VTI model has two interacting components – vehicle and track. The vehicle model describes the vertical dynamics of an 8th of a car. The track model considers an elastic rail on discrete (sleeper) supports. Each sleeper location can have its own stiffness, relative height and settlement characteristics. Dependent on the distribution of stiffness and settlement behaviour along the track together with the initial track geometry, each sleeper settles dependent on the number of load cycles (vehicle passes). The track model is initialized with measured vertical track geometry data and static track deflection data at the beginning (day 0) for two types of track sections in the field, a track section where concrete sleepers with Under Sleeper Pads (USP) are used and a track section where only concrete sleepers are used. Using the same settlement model parameters (constant along the track) for the two tracks, the physical-based VTI model can predict the different track geometry quality evolution for both tracks over 350 days. Finally, the VTI model is used to assess the track geometry deterioration when the track/vehicle properties are changed. The prediction strength of the fast VTI model based on the physical understanding can assist in designing and optimizing tracks and in supporting of maintenance activities. [ABSTRACT FROM AUTHOR]

In this article, the considered principles for the development of calculation schemes and the subsequent formation of vibration equations are a special case of classical simulation of motion in space of solid body systems connected in space by kinematic connections. This approach is useful with limited computational capabilities and an assumption of the relativelysmall bodymovements inherent in railway crew bodies, and reduces the task of motion research to analysis of fluctuations.Various design schemes of freight car truck, mathematical modeling of systems dynamics, "crew-track" safety of freight car movement and withdrawal under different technical conditionsof running parts and track are considered in this work.

Due to the fast growth of the population, multi-story structures are becoming more important. The fundamental issue with multi-story constructions is that they are sensitive to ground motion. The earthquake causes vibrating forces at the structure's foundation; as a result of these vibrations, the building experiences oscillations, which may severely destroy the structure. These oscillations become more pronounced as the structure's height rises, causing serious damage to large-scale facilities. Structures are intended to resist and withstand dynamic forces using a mix of strength, deformability, and energy absorption to protect them from substantial damage. Dampers are employed in high-rise structures in seismic zones to minimise vibrations caused by lateral stresses, such as strong winds and earthquakes, in order to prevent such catastrophic damage. RCC constructions of 10m, 20m, and 30m storeys are investigated in this research. The buildings have a rectangular form and are 20x45 m2 in size, with a seismic zone of V. E-Tabs software is used to analyse structures. For modelling of RC framed structures, the loading calculations were done according to code regulations, namely IS:1893- 2002, IS:875(Part-III)-1987, and IS:456-2000. With and without dampers, the parameters of base shear, storey drifts, storey forces, and storey stiffness are investigated. [ABSTRACT FROM AUTHOR]

Purpose. This study seeks to identify a rational way to modernize the brake lever transmission elements of freight car bogies. Methodology. Theoretical and operational studies concerning the structural limitations of the appearance of abnormal wear on the brake pads of the lever transmission of freight cars have been performed. The analytical approach to the justification of the technical and technological way of improving the existing design of the brake lever transmission is used. The recommendations of the modernization of the brake struts of the freight cars are given. Findings. Existing performance of existing brake lever transmissions has been found to be inefficient due to the inclination and pressing of the upper edges of the pads on the rolling surfaces of the wheels while running of trains without braking. Harmful friction with the formation of double friction wear of the working fluid leads to a condition where, due to the eccentric action of dynamic loads, up to 95% of the total number of pads are in a damaged state. The solutions for the restoration of existing brake beams designs were proposed. The chosen simplicity of the method of repair work is that the location of the service opening in the brake struts is transferred to a rational place. The method of modernization offered in the work is reduced to the fact that according to special calculations in the existing brake strut, at its restoration the minimum number of repair operations is performed. Originality. It is theoretically proved that in a brake beam a harmful torque from dynamic forces is formed, which causes abnormal wear of the brake pads. Calculated force analysis, taking into account these factors, identified the main disadvantage and identified the possibility of its elimination. A model was developed for the first time to reduce the non-normative wear of the brake pads due to the rational way of upgrading the brake strut. Mathematical calculations have been adapted to the formulation of the force loads of the elements of the brake levers, which tilt the brake beam to rest against the upper edges of the pads at the rolling surface of the wheels. Practical value. The results of the research were tested on real rolling stock and received practical recommendations, which should be used in the design, modernization and operation of brake systems of both operating fleet and three-element bogies of the new generation.

In the paper a procedure and methodology of acceptable calculations of powers, displacements (of amplitudes) and velocities of pulses according to ISO standards depending on the rotational speeds (frequencies) of rotor during attempts of dynamic breaking down taking into account effectiveness of vibration isolation were described. The proposed method is regarding one-sidedly hung rotors appearing in such appliances as rotors of fans, blowers, pumps and others. As permissible parameters of pulses values which are given in international standards PN-ISO-10816-1:1998P and PN-ISO-7919-1:2001 were assumed. Calculations were compared in the form of tables and they depicted with relevant graphs which have the character of useful nomograms. Also, recommendations for the design of the foundations and guidelines related to dimensions of the foundation, the weight and the way of fixing the device were given. In the end also closing remarks and conclusions were given.

Purpose. This research is aimed at revealing features of dual wear of pads in the brake system of freight cars. Methodology. The complex of theoretical and operational research concerning the causes and consequences of dual wear of pads, as the most widespread one in the freight cars, was conducted. Using the theory of planning the experiment based on the collected statistical material an adapted mathematical modeling of the dual wear process was performed and negative factors were determined. The Mathcad software and STATISTIKA software application were used. Findings. A comparative analysis of various devices for the uniform wear of brake pads showed insufficient efficiency. It has been established that typical devices of uniform wear of brake shoes (up to 95%) are in damaged condition due to the effect of significant dynamic loads. Therefore, the shoes are bent, pressed with their upper edges to the wheel threads and when driving in trains without braking do harmful friction with the formation of double frictional wear of the working body of the shoes. It has been theoretically proved that in a hinged connection of a vertical lever with a brake beam king post a harmfully acting torque from the gravitational forces is formed, which becomes the main cause of the dual wear of the brake shoes. Kinetostatic analysis, taking into account the dynamic forces in the unsprung parts of the bogie, has allowed establishing the cause of dual wear and determining the possibility of eliminating the specified torque in the existing brake system. According to the R & D and the Ukrzaliznytsia`s order the operational tests on 10 gondola cars constructed by Kriukiv Railway Car Building Works were performed. They confirmed the results of the theoretical studies. Originality. For the first time, it was discovered, the research was initiated and the definition – the dual deterioration of brake pads was proposed. A mathematical regression model was developed for determining the main cause of dual wear of pads in a typical mechanical braking system of three-element bogies. It was adapted the mathematical approach to the planning of experiments with the construction of the corresponding schemes-models, which revealed the malignant moment of forces, bending the break beam on the pendulum suspensions until the upper edges of the brake pads will be pressed to the wheel thread. Practical value. The results of the research can be used in the design, modernization and operation of brake systems for both the operational fleet, as well as a new generation of three-element bogies.

To create reliable and highly efficient, energy- saving machines for light industry, it is necessary to study the dynamic processes of movement of the links of the mechanisms of which they are composed. Especially such studies should be given attention for machines, the mechanisms of which have a cyclic nature of action. During the execution of a technological operation in light industry machines with a periodic cyclic movement of the working bodies, an uneven movement of the main shaft occurs. This is caused by the movement of the links of the mechanism with certain accelerations and taking into account the periodic nature of the action of technological loads, which vary in magnitude and direction. The uneven nature of the movement leads to the appearance of additional loads in the kinematic pairs of mechanisms, mechanical vibrations in the mechanical transmission systems of motion, leads to the appearance of vibrations and violations in the positioning of the working bodies, affects the technological process of the equipment. Uniform and stable tension of the threads is the key to a high-quality performance of the loop formation process in knitwear. Additional dynamic loads affect the technological tension of textile threads during equipment operation. These loads are caused by the accelerated movement of the links of the mechanism, which is especially important for technological equipment with the presence of a reverse working stroke of its links. In such mechanisms, the values of the angular acceleration of the links and the linear acceleration of their individual points can acquire critically permissible values. It is possible to ensure the movement of the working bodies of the machine according to the law for which the tension of the threads will be optimally necessary. To do this, you need to choose the right type of mechanism that sets them in motion. The aim of the work is to conduct a structural-kinematic research of the mechanism of the reversible movement of the needle drum of a knitting machine, which will justify the selection of the required type of mechanism for such equipment. The confirmation of the improvement of the conditions for the formation of loops when knitting on a knitting machine with a reversible needle drum movement, made on the basis of a rocker mechanism, has been obtained. [ABSTRACT FROM AUTHOR]

Haul roads are designed to bear dynamic truckloads generated during haulage. Current road design methods consider static truckloads, which are lower than dynamic loads. They are also unreliable for designing roads for ultra-large trucks. This paper introduces a methodology for designing roads using dynamic loads for any haul truck. A 3D rigid multi-body dynamic virtual model of CAT 797F was built, verified and validated in MSC.ADAMS to model truck tire dynamic forces generated during haulage. Maximum dynamic forces were 2.86 times static force at rated payload. Industrial useable models that capture truck dynamics are proposed to improve road structural design. [ABSTRACT FROM AUTHOR]

In this article, the considered principles for the development of calculation schemes and the subsequent formation of vibration equations are a special case of classical simulation of motion in space of solid body systems connected in space by kinematic connections. This approach is useful with limited computational capabilities and an assumption of the relatively small body movements inherent in railway crew bodies, and reduces the task of motion research to analysis of fluctuations. Various design schemes of freight car truck, mathematical modeling of systems dynamics, "crew-track" safety of freight car movement and withdrawal under different technical conditions of running parts and track are considered in this work. [ABSTRACT FROM AUTHOR]

Copyright of Maintenance & Reliability / Eksploatacja i Niezawodność is the property of Polish Scientific & Technical Society Consumables, Polish Maintenance Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Trucks experience excitations during haulage due to road roughness, generating dynamic loads. Current mine haul road design techniques assume static tire loads, ignoring dynamic forces. This paper presents mathematical models for estimating tire dynamic forces on haul roads. Models were solved in Simulink® and RStudio® to generate random road profile (class D) according to ISO 8608, and compute dynamic forces for 59/80R63 tire. Results show that road roughness significantly affects impact forces on roads, with tire dynamic forces (1638.67 kN) ~ 1.6 times static forces (~1025 kN) at rated tire payloads. The method presented gives realistic estimates of tire impact forces, which serves as useful input for haul road design. [ABSTRACT FROM AUTHOR]

Background: When transporting liquids, in particularly over long distances, dynamic forces in the system can present a risk. The larger the system size, and the greater the pressure, the more harmful the impact is of such forces. Water is transported in this way for domestic, industrial, and fire-fighting purposes. One of the impulses of dynamic force application may be the transition of the pressure wave in the water hammer. Methods: In this paper, the results of measured dynamic forces and associated displacements recorded on the model caused by transient flow conditions are presented. For measured forces, the displacements of the pipe were also calculated by using the oscillation motion equations. Force measurements and displacement analyses were carried out in laboratory on the model of a simple fire protection system equipped with three nozzles. Results and Conclusions: The measurement results and calculations were used to calibrate a mathematical model created using MATLAB software. [ABSTRACT FROM AUTHOR]

In this paper author depicts the results of the sea trials of the operational test of a Hiload technology at sea waves with the numerical analysis for the dynamic forces and operational risk. The research was carried out on board MT “Navion Anglia” which was engaged in a towing operation through the Atlantic Ocean with a “Hiload DP1” prototype unit docked on her portside alongside, with different ship’s draft and in different weather conditions. Additionally in this paper author presents the methods that can be used for estimating the safety factor SF against sliding and/or operational risk for the towing and/or manoeuvring operation with a “Hiload DP1” unit docked alongside at the open sea.

The possibility of applying the methods of active damping of vibration and pressure pulsations for reducing their transfer from power plants into the environment, the seating, and the industrial premises are considered. The results of experimental works implemented by the authors on the active broadband damping of vibration and dynamic forces after shock-absorption up to 15 dB in the frequency band up to 150 Hz, of water pressure pulsations in the pipeline up to 20 dB in the frequency band up to 600 Hz, and of spatial low-frequency air noise indoors of a diesel generator at discrete frequency up to 20 dB are presented. It is shown that a reduction of vibration transfer through a vibration-isolating junction (expansion joints) of pipelines with liquid is the most complicated and has hardly been developed so far. This problem is essential for vibration isolation of power equipment from the seating and the environment through pipelines with water and steam in the power and transport engineering, shipbuilding, and in oil and gas pipelines in pumping stations. For improving efficiency, reducing the energy consumption, and decreasing the overall dimensions of equipment, it is advisable to combine the work of an active system with passive damping means, the use of which is not always sufficient. The executive component of the systems of active damping should be placed behind the vibration isolators (expansion joints). It is shown that the existence of working medium and connection of vibration with pressure pulsations in existing designs of pipeline expansion joints lead to growth of vibration stiffness of the expansion joint with the environment by two and more orders as compared with the static stiffness and makes difficulties for using the active methods. For active damping of vibration transfer through expansion joints of pipelines with a liquid, it is necessary to develop expansion joint structures with minimal connection of vibrations and pulsations and minimal vibration stiffness in the specified frequency range. The example of structure of such expansion joint and its test results are presented. [ABSTRACT FROM AUTHOR]

The feasibility of an active low-frequency vibrational-isolation system with compensation of the dynamic forces on the housing by means of antiphase inertial forces is considered. This system effectively reduces the forces transmitted to the housing from vibrations of an elastically suspended mass in the low-frequency subresonance range. [ABSTRACT FROM AUTHOR]

The paper presents the advantages of suspension buildings and structures in comparison with the traditional buildings. It has been demonstrated, that during an earthquake the strains in the support structures of such buildings and structures are significantly reduced compared to the strains in traditional cantilever buildings. The advantage of the suspension structures is shown by the example of a water tower with a tank of a capacity of 50 m3. Various schemes of the considered construction are given: the construction freely suspended on the bearing frame, the construction with the suspended foundation (prototype). These schemes are compared with the scheme of the cantilever structure. It is proved that the dynamic forces arising from the ground oscillation in the suspended structure are less than the forces in the cantilever structure. The strains depend on the frequency and amplitude of the ground vibrations. The scheme of the forces’ adjustment by means of springs (dampers) is given. It is illustrated that by changing the flexural stiffness of the bearing frame, changing the stiffness of the damper, it is possible to adjust the frequency of oscillations and forces in the suspension building or structure.

These days we are witnessing an increase of container trafficin general and at sea in particular. In order to economizetheir business the ship owners are building bigger container vesselswhich can carry up to 8000 TEUs (Maersk line) and otherbig carriers are following suit. On the drawing board is the vesselof 12000 TEUs from the mentioned ship owner. Obviously,such large quantity of containers requires highly efficient lashingequipment in order to secure them, particularly thosestowed on the deck Under the deck, almost as a rule all contemporarycontainer ships have cell guides as securing devices.Attention in this work is focused on container lashing systemexposed on the ship's deck and the relevant forces acting on thelash system during transportation at sea. Once containers areloaded on the ship's deck they should be safely secured by oneof the lashing systems in order to prevent damage and that is theprincipal task of the lashing equipment engaged within theframe of the lash system. In order to fulfill its objective theforces acting on the container should be properly calculated.The acting forces, their influence and the way of calculatingthem have been explained for all the major ship movementsand suggestions for optimum lashing equipment are given.

The proposal for improving the constructive scheme of the supporting frame of the suspension building has been considered. The strains in its bearing elements due to earthquakes are significantly less than in the traditional cantilever buildings. In former schemes the vertical components of strains develop during horizontal oscillations of the grounds. This disadvantage has been eliminated now. It is shown that in the improved design of the structure under the earthquake the vertical component of vibrations is practically absent, due to arrangement of the suspension device strictly vertically. The numerical data for calculation results with variation of some characteristics of the supporting frame and suspensions have been shown in order to allow adjusting the dynamic strains at the vibrations of the base. The scheme for installation the vertical elements of the frame have been proposed. Its usage will allow to build the high-rise suspension buildings.

The applications of Atomic Force Microscopy (AFM) on the study of dynamic interactions and film drainage between deformable bodies dispersed in aqueous solutions are reviewed in this article. Novel experimental designs and recent advances in experimental methodologies are presented, which show the advantage of using AFM as a tool for probing colloidal interactions. The effects of both DLVO and non-DLVO forces on the colloid stabilization mechanism are discussed. Good agreement is found between the force – drop/bubble deformation behaviour revealed by AFM measurements and the theoretical modeling of film drainage process, giving a convincing explanation of the occurrence of certain phenomenon. However, the behaviour and shape of deformable drops as they approach or retract is still not well resolved. In addition, when surfactants are present further research is needed on the absorption of surfactant molecules into the interfaces, their mobility and the effects on interfacial film properties. [ABSTRACT FROM AUTHOR]