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Objectives: This study investigates the impact of drill play on the precision of implant positioning under lateral forces in guided implantology. Materials and Methods: An in vitro experiment was conducted using artificial bone blocks and the SIC Invent‐guided surgery implant system. Custom drill guides were designed, and 3D‐printed, using three sleeve types: sleeveless, a big sleeve, and a small sleeve. Drillings were performed with varying lateral forces, and deviations in angle, depth, and position were measured. Results: Sleeveless guides showed the highest variability in deviations, with a maximum deviation of 3.92 mm under extreme lateral forces. Big sleeve guides provided the most consistent precision, with deviations ranging from 0.42 to 1.33 mm. Small sleeve guides showed moderate precision, with deviations from 0.14 to 2.17 mm. Higher lateral forces generally increased deviations across all guide types. Conclusions: Drill play significantly affects the precision of guided implant drilling, with lateral forces causing deviations from the planned implant position. Big sleeve guides offer better precision under lateral loads compared to sleeveless and small sleeve guides. Strict adherence to the drilling protocol is essential to minimize errors and ensure optimal implant positioning. [ABSTRACT FROM AUTHOR]

Because of wake instability, bubbles always ascend along an unstable path, which is not considered when simulating their movement in steel refining and continuous casting systems. Utilizing the 3D shadow image method, a quantitative characterization of the bubble trajectories is conducted to establish a bubble path oscillation model considering the zigzag lateral movement of bubbles due to asymmetric wake shedding. This model is incorporated into a rectilinear bubble motion model within the Lagrangian framework and then used to simulate the free ascent of single bubbles within the 2.15–2.55 mm range. The predicted bubble ascent velocities and trajectories agree well with the experimental. The spatial position, velocity, acceleration, forces, volume swept by bubbles, and bubble residence time are discussed. The results shown that the dominant force in the horizontal direction is the lateral force, followed by the drag and virtual mass force. Compared to the rectilinear path model, the volume swept by bubbles with initial diameters of 2.15, 2.25, 2.34, 2.45, and 2.55 mm in this model increases by 30.8%, 32.0%, 34.0%, 31.5%, and 29.6%, respectively. These findings help accurately predict the path of bubbles and also may contribute to a better understanding of bubble dynamics in bubble metallurgy and clean steel production. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives This study investigates the impact of drill play on the precision of implant positioning under lateral forces in guided implantology. Materials and Methods An in vitro experiment was conducted using artificial bone blocks and the SIC Invent‐guided surgery implant system. Custom drill guides were designed, and 3D‐printed, using three sleeve types: sleeveless, a big sleeve, and a small sleeve. Drillings were performed with varying lateral forces, and deviations in angle, depth, and position were measured. Results Sleeveless guides showed the highest variability in deviations, with a maximum deviation of 3.92 mm under extreme lateral forces. Big sleeve guides provided the most consistent precision, with deviations ranging from 0.42 to 1.33 mm. Small sleeve guides showed moderate precision, with deviations from 0.14 to 2.17 mm. Higher lateral forces generally increased deviations across all guide types. Conclusions Drill play significantly affects the precision of guided implant drilling, with lateral forces causing deviations from the planned implant position. Big sleeve guides offer better precision under lateral loads compared to sleeveless and small sleeve guides. Strict adherence to the drilling protocol is essential to minimize errors and ensure optimal implant positioning.

Introduction. The article considers the prerequisites for choosing the most expedient reference method of experimental determination (measurement) of the lateral (horizontal transverse) force acting in the contact zone of the wheel and the rail head in relation to the procedure for establishing the conditions for the circulation of rolling stock on the railway network. This is one of the important force factors of the interaction of the rolling stock with the elements of the permanent way of the railway track. The author presents a set of methods for experimental evaluation of lateral forces based on the measurement of rail deformations, which were applied in the works of certified testing centres for railway equipment in Russia and the Commonwealth states.Materials and methods. Based on a set of known experimental techniques, the author proposed to take statistical estimates of the measurement error established by the current interstate regulations as criteria for the validity of the choice of a refe rence measurement technique. Determination of the reference measurement technique involves conducting purposeful experiments with similar conditions, including the types of rolling stock under test, the parameters of the device and structure of the permanent way of the measured section, meteorological parameters, etc. The author has applied the procedures that include the choice and justification of the reference value of the measured indicator, comparison of statistical estimates of the measurement error of lateral forces along with the requirements imposed on the conditions for conducting experiments in accordance with the requirements of regulatory documents of Rosstandart.Results. As a result, the author described the methods for statistical processing of experimental information of various considered techniques for measuring lateral forces, which enabled to justify the choice of the reference measurement technique.Discussion and conclusion. The presented method for determining the reference method for measuring the lateral forces of the impact of the wheel on the rail head according to the deformations of the rail considers the requirements of the regulatory documents of Rosstandart and can be used in the experimental evaluation of interaction indicators in the mechanical wheel — rail system.

Reducing the intensity of rail lateral wear remains an important task for industry science. As part of solving this problem, studies are being carried out on the influence of the geometry of the rail track on the wear of rails, the intensity of the force interaction of wheels and rails, the tribological characteristics of the contacting surfaces. The article focuses on the influence on the wear of the geometry of the rail track, namely the rail canting. The definition of the stability of the rail canting has been formulated, which makes it possible to proceed to the assessment of this indicator both in time and in the length of the track section. The assessment of the canting stability over time was carried out on the basis of experimental data obtained in the course of field studies carried out in 2019–2020 on the Moscow Railway. As a result of evaluating these data, the dependence of the change in the average values and the standard deviation of the rail canting in the section on time was built. The average values and standard deviation of the canting in the investigated area are considered in this article as a set of parameters that make it possible to assess the canting stability. In addition to these parameters, it is proposed to evaluate the canting stability along the length of the section based on the canting offset and the standard deviation. The assessment of the stability of the rail canting along the length of the section was carried out using calculations performed in the “Universal Mechanism” software package. As a result of calculations, the values of frame and lateral forces were obtained and an assessment of their maximum and average values at the site was made. This made it possible to answer the question: how does the retraction of the rail canting affect the level of force interaction at the point of contact between the wheels and rails, and, hence, the wear rate?

• An innovative model for pedestrian-footbridge synchronization is developed. • Contributions of pedestrians vary according to their moving positions on bridge. • Gait frequency of a pedestrian follows Gaussian distribution and pedestrians adjust their phase in response to bridge vibration. • Excessive lateral vibration of London Millennium Footbridge is reproduced. • Parametric investigations are made to detect main effects of pedestrians on bridge vibration. The mechanism which results in the synchronization of people walking across footbridges with the bridges fundamental horizontal frequency is studied. The lateral vibration of a bridge subjected to walking pedestrians is modelled by considering the bridge to be a slender beam. The effect of bridge motion on the footfall forces of walking pedestrians is not considered. The contribution of pedestrians varies with their position on the bridge. It is assumed that the walking gait frequency of a pedestrian follows a Gaussian distribution and pedestrians can unconsciously adjust the phase of their walking cycle closer to that of the bridge, based on the theory of coupled oscillators. A time-dependent nonlinear dynamic equation is derived using the modal expansion approach. The model is then applied to the north span of the Millennium Bridge in London, to produce its excessive lateral vibrations. Agreement between the results and the existing observations supports the rationality and reliability of the method. Several parameters, in particular the walking gait frequency of pedestrians, crowd sensitivity to bridge motion, bridge frequency, bridge damping and different load conditions are investigated. The numerical simulation shows that these parameters have different degrees of impact on the critical number of pedestrians triggering excessive vibrations. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to assess the effect on microleakage of cyclic lateral fatigue forces in different types of cervical resin composite restorations. Method and materials: V-notch cavities were prepared at the cementoenamel junction in 60 extracted human premolars and restored with a bonding system along with one of the following resin composites: hybrid resin composite, microfilled resin composite, and flowable resin composite (20 each). Ten specimens from each group of 20 were subjected to 8.400 cycles of lateral fatigue forces (44 N) at the occlusal half of the clinical crown in a machine specifically developed for this purpose. The other 10 specimens of each group served as controls, representing the microleakage that occurred without lateral fatigue forces. All specimens were stained with a 50% silver nitrate solution and sectioned sagittally. A scoring system of 0 to 6 was used to record the amount of die penetration along the restoration-toot h interface. Results: There was leakage in both the fatigued specimens and the nonfatigued control specimens. There were significant differences in the mean values of microleakage for the restorative materials studied. In the nonfatigued groups, hybrid resin specimens exhibited significantly more microleakage at the dentin-resin Interface than did microfilled or flowable resin specimens. In the fatigued groups, hybrid resin specimens exhibited significantly more leakage at the dentin-resin interface than did microfilled resin specimens. Conclusion: The least elastic resin composite tested, the hybrid material, generally showed the most leakage. This suggests that the elasticity of these resin composite restorative materials may be a factor in the amount of microleakage in cervical restorations. [ABSTRACT FROM AUTHOR]

When implementing new or modernized rolling the train in most cases is in the range of 0.9-0.95 and varies de-stock, one of the main problems is the provision of both traffic pending on the position in the track of a group of wheelsets. The safety, and the strength of the carriage and the ways that are de-correlation level of the frame force measured in the carriage and termined by forces in the wheel - rail system. It is almost impossible the sum of lateral forces by its average values is 0.98. A practical to directly measure the forces of interaction between the crew and method for determining the forces of interaction with respect to the track. Their determination can be carried out by measuring the stresses in the neck of a rail was proposed by Schlumpf. It involves stresses in rails, the interdependencies of which with forces are of determining the difference of the moments in the two cross sections a probabilistic nature. Correlation of the strength and stresses for of the rail neck with the angular moment of resistance to bending being equal. In this case, when the scale factors are equal to the difference of the moments, the lateral force is determined. The calculations were made by subtracting electrical signals (four strain gauges were included in the shoulders of the Wheatstone bridge), and a separate bridge was used to determine the vertical load. Errors in determining the lateral force are due to inaccurate location of the sensor sticking, the difference in the dimensions of the rail neck and the displacement of the point of application of the vertical load on the rail head. However, since the maximum forces are realized when the wheel climbs on the rail, this displacement varies insignificantly. Therefore, the results obtained can be used in conducting certification tests. The method of digital processing of data on stresses at three points of the rail neck requires for its implementation more strain gages, but the accuracy of its results is much higher, since it depends only on the errors of preliminary calibration of the cross sections. The error in calculating the forces does not exceed 4%, which shows the expediency of using the three-point method in determining the interaction forces to establish the conditions of circulation.

On the basis of existing practice and analysis of domestic and foreign sources a classification of methods for experimental evaluation of the lateral forces of interaction between the wheel of the railway carriage and the rail head is given. A review of the various experimental methods implemented, using gauges, mounted on elements of track superstructure, is provided. Brief description of the principal methods of using the elastic properties of rails for the experimental evaluation of lateral forces using strain gauges is made. Article provides methods for measuring the lateral force, based on the registration of the forces acting from the rail to the sleeper, and special elastic rail sensing elements embedded in the rail neck. Current trends of improving registration system of lateral forces, including ways to "continuous" registration of the lateral forces are shown. Review includes recommendations for evaluating the adequacy of the measuring lateral forces on the basis of analysis of experimental data from a number of dynamic interaction processes in rolling stock and track interaction recorded simultaneously with the side forces on the same measurement track sections, including dynamic stresses in the edges of the rail foot of horizontal transverse forces, acting on the rail to the sleeper, frame strength.

Eccentrically braced steel frames are structures used to resist lateral loads as they combine the ductility that is characteristic of moment frames and the stiffness associated with braced frames. Damper devices can be used as the main source of energy dissipation and have become more popular lately for the lateral control of structures. Control devices generally reduce damage by increasing structural safety, serviceability and preventing the building from collapse during vibration. This study focused on improving the performance of the structures with a proposed damping system, which has more advantages than eccentrically braced frames (EBFs). It can accommodate many architectural features and make construction and complementarity in the structures easier. The purpose of this study is to evaluate the performance of the structure with the proposed damping system and its construction in the building. [ABSTRACT FROM AUTHOR]

Abstract—Nanotribological tests via atomic force microscopy were optimized by recording the lateral interaction forces between the probe tip and the sample surface in the contact mode. In the case of thin film metal materials, the technique enabled us to determine independently the sliding force and the static friction force, which reduced the measurement error of tribological characteristics at the nanoscale by 3—5 times. [ABSTRACT FROM AUTHOR]

Since the column and the top beam of the present four-bar hydraulic support fail to bear the lateral force,the lateral force is transferred to the rod via the shield beam,which often leads to the falling down of the support or damage of the support mechanism. With regard of such a theoretical shortcoming,this article introduces a new type of double parallel hydraulic support based on the 3-RPC parallel mechanism. The working space of the hydraulic support is analyzed and the trajectory formula of the top beam is presented. Through the force analysis of the hydraulic support under the condition of partial load and large dip angle,the hydraulic support can bear the forces from three directions and an accurate mechanical relational expression is given. ADAMS is applied to do the stability simulation of the hydraulic support. The results show that the design of such a hydraulic support meets the supporting requirements of coal mines and it is feasible in technology.

This paper presents a new accurate multiple model of nonlinear pneumatic lateral forces. The bicycle representation is used in order to build up an easy implemented vehicle dynamic model. Moreover, the Takagi–Sugeno fuzzy approach is applied in order to handle the vehicle model nonlinearities. This structure allows for taking into account the small variation of the vehicle longitudinal velocity. Subsequently, a Fault Tolerant Control strategy that is based on a bank of fuzzy Luenberger observers is proposed. The robustness of the control scheme against external noises is guaranteed by applying H∞ performance. Sufficient stability conditions that are based on Lyapunov method are formulated as Linear Matrix Inequality. Thus, allowing the computation of the observers’ and the controllers’ gains by using MATLAB. Finally, the simulation examples are performed to show the effectiveness of our proposal.

There are discussed curve negotiation related vehicle - track interaction processes. Not only maximum but also averaged values of the interaction indices ought to be taken into consideration while analyzing the respective calculation and test results. They determine to a greater extent the mechanical forces-caused processes governing track and vehicle related energy consumption and wear rate. Also presented are factors influencing the wheel - rail dynamic interaction processes, characteristic of railway car movement within a train consist. With railway track in a good condition values of frame forces are governed not so much by the track curvature as by the total of inertial forces and external loads acting upon the car sprung parts. In-track lateral forces represent the sum of the frame forces acting upon a wheelset and friction forces within a wheel -rail contact. Lateral forces’ values essentially depend not only on the track irregularities, but also on the contact surface friction which value increases in the steep curves. That’s why the force acting from the wheel may significantly outweigh the frame force acting upon the wheelset. And this is the reason for the gauge outward pressure rate to be different in the steep and smooth curves at the within-one-order frame forces’ values. With a wheel attacking the outer rail line the value of the lateral force applied to this wheel is governed not only by the frame force acting on the boxes and the inertia of the respective wheelset, but also by the friction value on the other wheel of the wheelset which is forced contrariwise, thus side-shifting the inner rail and causing additional track spreading. Operational experience witness that in terms of equal unbalanced accelerations’ values track disconsolidation and spreading are greater in the steep rather than in the smooth curves. This indicates the relevance of applying friction modifiers to the inner rails’ running surfaces.

Hyaluronan (HA) possesses manifold mechanical and signaling properties in the body. Most of these activities are largely regulated by its molecular weight, which often triggers opposing functions. However the molecular basis for such function distinction between HA size categories remains unclear. Using a combination of biophysical techniques, we measured the physical forces between HA ligand and its specific receptor CD44 in both normal and lateral directions, at different HA molecular weights and bound states. It was found that the impact of HA multivalency is more than just the sum of separate monovalent bindings. The HA-CD44 specific interaction enhances with HA molecular weight and the maximum binding occurs at ∼1000 kD, possibly due to the balance between multivalent HA zipping effect and conformational entropy. High friction patches, probably from CD44 protein clustering, was observed in friction force microscopy (FFM) upon HA shearing, which is also dependent on HA molecular weight. These results could help to understand the biophysical mechanism of HA in regulating CD44-induced physiological activities and thus facilitate the new design of HA-based material in fine tuning the receptor responses. [ABSTRACT FROM AUTHOR]

Computational fluid dynamic (CFD) methods are used to investigate the enhancement of the solid-gas separation efficiency by adding tangential chambers to the conical section of a conventional cyclone separator. It is shown that the addition of the tangential chamber enhances the separation of the particles near the conical section wall, and hence the overall separation efficiency, particularly for small particles (1–3 μm). This enhancement occurs with only an 8% increase in the pressure drop between the inlet and outlet of the cyclone. The effects of the inlet velocity and the number of the tangential chambers on the separation efficiency are studied to find the optimum conditions. It is shown that the increase in the velocity enhances the efficiency at the expense of an increase in the pressure drop (the increase in the inlet velocity from 14 to 20 m/s doubles the pressure drop). The model also shows that the addition of one tangential chamber produces a lower dissipation rate of turbulence in the cyclone as compared to multiple chambers, and hence a higher separation efficiency. The efficiency of the proposed geometrical modification is also compared against the conventional cyclone design and that with another geometrical modification reported in the literature (i.e., a cyclone with an elongated conical length). The results reveal that the proposed modification in this paper enhances the separation efficiency for small particles (less than 3 μm) up to 50% compared to the conventional and the elongated designs and 15% for large particles (larger than 6 μm) compared to the conventional design. The proposed modification was also compared to the conventional design in terms of the erosion rate of the cyclone walls, which is increased by 50%. [ABSTRACT FROM AUTHOR]

A control scheme named the variable-lateral-force cavitator, which is focused on the control of lift force, drag force and lateral forces for underwater supercavity vehicles was proposed, and the supercavitating flow around the cavitator was investigated numerically using the mixture multiphase flow model. It is verified that the forces of pitching, yawing, drag and lift, as well as the supercavity size of the underwater vehicle can be effectively regulated through the movements of the control element of the variable-lateral-force cavitator in the radial and circumferential directions. In addition, if the control element on either side protrudes to a height of 5% of the diameter of the front cavitator, an amount of forces of pitching and yawing equivalent to 30% of the drag force will be produced, and the supercavity section appears concave inwards simultaneously. It is also found that both the drag force and lift force of the variable-lateral-force cavitator decline as the angle of attack increases. [ABSTRACT FROM AUTHOR]

We propose a geometry for a piezoelectric SPM sensor that can be used for combined AFM/LFM/STM. The sensor utilises symmetry to provide a lateral mode without the need to excite torsional modes. The symmetry allows normal and lateral motion to be completely isolated, even when introducing large tips to tune the dynamic properties to optimal values.

In qPlus atomic force microscopy the tip length can in principle approach the length of the cantilever. We present a detailed mathematical model of the effects this has on the dynamic properties of the qPlus sensor. The resulting, experimentally confirmed motion of the tip apex is shown to have a large lateral component, raising interesting questions for both calibration and force-spectroscopy measurements.

The concept of managing and adjustment of friction between the wheel and rail has a long history within the operation of railways systems. In the past, adjustment/management has been limited to gauge face lubrication and the use of sanding equipment. The introduction of the top of rail (TOR) friction modifier (FM) over the last 20 years now allows for the modification of the friction at the top of rail–wheel tread interface. This paper focusses on the concept of TOR friction adjustment. Recent developments have led to a new generation of products, defined here as, TOR lubricants (oil and/or grease-based) and hybrid materials (oil/water mixtures), which are non-drying or slow drying. Definitions and functional difference are detailed and contrasted with that of the water-based drying FM. The water-based TOR-FM once applied rapidly dries, mixes with the existing third-body layer, and allows for the accommodation of shear displacement. TOR lubricants and hybrid materials rely on mixed boundary layer lubrication, contrary to application of the water-based TOR-FM. It has been shown that the adhesion level is highly influenced by the lubricant application rates. The risks and benefits (lateral force reduction, corrugation mitigation, and impact on energy consumption and influence on rolling contact fatigue) are discussed for all product classifications. However, a lack of data exists for the TOR lubricants especially in the area of rolling contact fatigue where laboratory studies have identified the possibility of crack interaction. Whilst it can be seen that TOR lubricants have the ability to provide similar benefits to that of a water-based FM, they exhibit a strong dependency on the application rate which may lend itself to adhesion and RCF issues. Further work is recommended in this area. [ABSTRACT FROM AUTHOR]

Current seismic design practice related to integral bridge girder-to-cap beam connections allows little or no lateral seismic load to be distributed beyond the girders immediately adjacent to the column. However, distribution results from several large-scale tests have shown that the distribution of column seismic moment typically engages all the girders. An approach utilizing simple stiffness models to predict distribution in integral bridge structures is presented in detail; distribution predictions based on grillage analyses also are compared. The experimental results and the analytical results from the stiffness and grillage models show that current design methods related to vertical load distribution are sufficiently accurate. However, when applied to the distribution of lateral load, similarly obtained results reveal that current design practice does not appropriately account for the amount of load that is distributed beyond the girders adjacent to the column to the nonadjacent girders. The current practice leads to excessive girder-to-cap connection reinforcement, increased girder depth, unnecessarily high seismic mass, and increased construction cost. Finally, this paper makes recommendations for more appropriate distribution of seismic lateral load in integral bridge superstructures. [ABSTRACT FROM AUTHOR]

The behavior of a solid shear wall is well understood, and the rigidity of the wall can be accurately determined using a simple hand-calculated approach. However, the computation of the rigidity of a shear wall with openings is significantly more complex than that of a solid wall and, therefore, can only be accurately determined by using the computer-aided FEM. Although several conventional simplified hand-calculated procedures are available for practicing structural engineers, results from those procedures are highly approximate and may not be reliable. Therefore, a more accurate hand-calculated procedure, which considers the rotation at the tops of the piers and the effective length of the piers, is proposed to calculate the rigidity of shear walls with openings. A total of three different configurations of shear walls with openings are used as examples to assess the accuracy of the newly proposed hand-calculated method. The accuracy of the results derived from the newly proposed hand-calculated procedure has significantly been improved over the conventional hand-calculated procedures. [ABSTRACT FROM AUTHOR]

Multi-storied frame structures have always been in the lime-light as far as research and theoretical development is concerned. The behavior of lateral forces on the structures is a specific area on which considerable research has been done over the last few decades. Several experiences of the last century have brought the attention of the engineers to such forces which, at times, were significant enough to change the design criteria. In Pakistan, considerations for such lateral forces had been made compulsory by the building control authorities across the country, and the same were welcomed, after the catastrophic disaster of October 2005. However, the developmental research in the field is still underway like in rest of the world. Most of the structural designers in Pakistan depend on Computer Aided Design software for analysis of lateral forces; however, significance of classical methods cannot be over-ruled. In this study, an attempt was made by studying the comparison between the design results of a multi-storied moment resisting frame structure in Karachi using the D-value method and ETABS software. There are several parameters on which the comparison could be based, but as the designers are mostly concerned about the design moments, the comparison is based upon the difference between the moments caused on respective joints by the lateral forces only. D-value method is not only a straightforward method but also may be considered to be the nearest compatible method to the finite element method (ETABS), for the analysis of lateral forces on super-structures, as its results showed a variation of only 20% with that of the results from ETABS. It is recommended for preferable use D-value method upon other methods of analysis when it comes to the scrutiny or verification of moments from the CAD software however, the difference between the comparative results may vary for type of structures other than the moment resisting frame structures. [ABSTRACT FROM AUTHOR]

The second method (known as Method B), specified in the 1997 Uniform Building Code Static Force Procedure, is a rational and accurate approach for finding the fundamental period of a frame. The formula used in Method B, however, is not a popular formula because it involves time-consuming computations of frame deflections which usually require the use of computer software. A hand-calculated approach for the computation of frame deflections using a calculator rather than a computer is suggested in this paper in order to turn Method B into a practical method for determining the fundamental periods of low-rise moment frames. The general stiffness matrix of a three-story, three-bay frame presented in this paper is intended to be used as an aid to compute the deflections for any moment frame within three stories in height and within three bays in width. Examples shown in this paper illustrate the step by step procedure for the computation of the fundamental periods of low-rise moment frames using the proposed hand-calculated approach. These examples also demonstrate that the results obtained from the proposed hand-calculated static approach agree with that obtained from the dynamic analysis.

One of the limitations structural engineers face when designing a building and, in general, any structure in Guadua angustifolia Kunth is the lack of technical information related to the parameters needed for a proper numerical model of the same. The degree of embedding that can provide support to its structural element is an important variable during structural modeling, because the judgment of the engineer in the selection of this parameter for modeling can influence the rigidity of the structure and, therefore, its period of vibration. This paper presents the experimental results of the constant of rigidity of a connection between a Guadua angustifolia Kunth column and a concrete element that is part of the foundation, when the column is under monotonic lateral loads. Additionally, the impact of each component of the connection on the rigidity of the structure has been evaluated. [ABSTRACT FROM AUTHOR]

A steel plate shear wall (SPSW) with thin, unstiffened web plates is one type of seismic lateral force-resisting system that is gaining popularity. SPSWs are used in low to midrise building construction typically with two or more frames in each orthogonal direction to resist seismic loading combined with gravity framing. The SPSWs therefore control the lateral force response of the building and the building's natural periods of vibration. For design of any seismic load-resisting system, an estimation of the building's first-mode period is necessary to calculate seismic loads and estimate resulting frame drift. This paper presents a method for estimating the first three natural periods of a SPSW with nonuniform properties along its height, accounting for both shear and flexural deformations of the system. The proposed method approximates the SPSW frame as shear and flexural systems separately to determine corresponding frequencies and then combines these frequencies using Dunkerley's equation. A comparison of periods estimated using the approximate method with those obtained from modal analysis of detailed finite-element models suggests that the proposed method is appropriate for estimating the first-mode period of SPSW frames. The proposed method could be valuable for refining the seismic design of these frames or for verifying the results of large, complex steel plate shear wall building models. [ABSTRACT FROM AUTHOR]

This paper focuses on the development of a front- and rear-wheel-independent drive-type electric vehicle (EV) (FRID EV) as a next-generation EV. The ideal characteristics of a FRID EV promote good performance and safety and are the result of structural features that independently control the driving and braking torques of the front and rear wheels. The first characteristic is the failsafe function. This function enables vehicles to continue running without any unexpected or sudden stops, even if one of the propulsion systems fails. The second characteristic is a function that performs efficient acceleration and deceleration on all road surfaces. This function works by distributing the driving or braking torques to the front and rear wheels, taking into consideration load movement. The third characteristic ensures that the vehicle runs safely on roads with a low friction coefficient (\mu), such as icy roads. In this paper, we propose a driving torque distribution method when cornering and a braking torque distribution method; these methods are related to the third characteristic, and they are particularly effective when driving on roads with ultralow \mu. We verify the effectiveness of the proposed torque control methods through simulations and experiments on the ultralow-\mu road surface with a \mu of 0.1. [ABSTRACT FROM PUBLISHER]

An optimization method based on uniform damage distribution is used to find optimum design load distribution for seismic design of regular and irregular shear-buildings to achieve minimum structural damage. By using 75 synthetic spectrum-compatible earthquakes, optimum design load distributions are obtained for different performance targets, dynamic characteristics, and site soil classifications. For the same structural weight, optimum designed buildings experience up to 40% less global damage compared to code-based designed buildings. A new general load distribution equation is presented for optimum performance-based seismic design of structures which leads to a more efficient use of structural materials and better seismic performance. [ABSTRACT FROM PUBLISHER]

Objective: To evaluation the influences of lateral occlusal forces to stress distribution in filling material after the restorative therapy of wedge-shaped defect. Methods: A three-dimensional finite element model of maxillary first premolar with wedge-shaped defect was established. The defect zone of the model with simulated glass ionomer was restored. Loads of different directions were applied on the model and stress analysis of restorative material were conducted. Results: When the loading direction was parallel to the tooth long axis, restorative material unit subjected to relative small stress. When the loading direction was vertical to the cusp inclined plane, stress endured by restorative material unit was significantly increased, as the angle of loading inclination increased, the increase of stress became more pronounced. Conclusion: After the restorative treatment of wedge-shaped defects in clinical, occlusal adjustment should be applied to reduce the inclination of cusp to relieve the lateral forces subjected by tooth so as to ease the stress burden of restorative material. [ABSTRACT FROM AUTHOR]

This paper describes a displacement-based method of analysis for the performance-based seismic design of regular buildings with reinforced-concrete bearing walls acting as the lateral-force resisting system. The method considers two performance levels: immediate occupancy (IO) and life safety (LS), each anchored at a specific seismic hazard level. It explicitly accounts for the combined effects of inelastic first mode of response, kinematic system overstrength, and higher modes of response. Quantification of these effects is required to capacity-protect the structure and to ensure the intended performance. As an example, the method is applied to a full-scale 7-story reinforced-concrete building slice, built and tested on the George E. Brown Jr. Network for Earthquake Engineering Simulation Large Outdoor High-Performance Shake Table at the University of California-San Diego. The response of the test building largely verified the method discussed in this paper. [ABSTRACT FROM AUTHOR]

This paper is a companion to 'Displacement-Based Method of Analysis for Regular Reinforced-Concrete Wall Buildings: Application to a Full-Scale 7-Story Building Slice Tested at UC-San Diego' and presents key results obtained from a full-scale 7-story reinforced concrete building slice built and tested on the George E. Brown Jr. Network for Earthquake Engineering Simulation Large Outdoor High-Performance Shake Table at the University of California, San Diego. The building was tested in two phases. This paper discusses the main test results obtained during Phase I of the experimental program. In this phase, the building had a rectangular load-bearing wall acting as the main lateral force-resisting element. The building was subjected to four historical California input ground motions, including the strong-intensity near-fault Sylmar record, which induced significant nonlinear response. The test addressed the dynamic response of the building, including the interaction between the walls, the slabs, and the gravity system as well as four issues relevant to construction optimization: (1) reduction in the longitudinal reinforcement; (2) use of a single curtain of reinforcement to transfer shear; (3) constrain of plasticity in the first level of the wall using capacity design; and (4) use of resistance-welded reinforcement in the boundary elements of the first level of the walls. The building responded very satisfactorily to the ground motions reproduced by the shake table and met all performance objectives. The effects of kinematic system overstrength and higher modes of response in the experimental response were important; this verified to a large extent the displacement-based method of analysis presented in the companion paper. [ABSTRACT FROM AUTHOR]

Unstiffened steel plate shear walls are an effective and economical method of resisting lateral forces on structures due to wind and earthquakes. Structural engineers require the ability to assess the inelastic structural response of steel plate shear walls using conventional analysis software that is commonly available and is relatively simple and expeditious to use. The strip model, a widely accepted analytical tool for steel plate shear wall analysis, is refined based on phenomena observed during loading of steel plate shear walls in the laboratory. Since the original strip model was proposed as an elastic analysis tool, these refinements are made primarily to achieve an accurate representation of yielding and eventual deterioration of the wall, although moderate improvements in initial stiffness predictions are also made. In assessing each of the proposed refinements, modeling efficiency is evaluated against the accuracy of the solution. A parametric study using the modified strip model examines the effect of varying the angle of inclination of the tension strips on the predicted inelastic behavior of the model. Notably, it was found that the ultimate capacities of steel plate shear wall models with a wide variety of configurations vary little with the variation of the inclination of the strips. [ABSTRACT FROM AUTHOR]

Today, especially parallel to the progress in semiconductor technology, the developing nanotechnology makes the mechanical systems and structures in micro/nano scale possible. Mechanical structures in micro/nano scale such as gas turbines, pumps, mixers, heat exchangers, valves etc., bring the following topics into consideration: how vary thermodynamic properties of gases, how it can be modeled, how one can make use of these differences, how new devices and technologies can be developed in this scale. In this perspective, the subject of quantum size effects (QSE) on thermodynamics of gases at micro/nano scale is a new research area and it has many potential applications from the technologies of genetic, space and energy to the military ones. In nano scale, thermodynamic properties (TP) of gases differ from those in macro scales. One of the reasons of this difference is the QSE, which become important when the thermal de Broglie wavelength of particles ( λT ) is not negligible in comparison with the characteristic length of the system (L=V/A, V volume, A surface area). In such a case, the continuum approximation for the energy eigenvalues of particles becomes invalid and the discrete nature of energy eigenvalues causes QSE, which are noticeable in nano scale. QSE make the thermodynamic state functions depend on geometry (shape) and size of the system, and QSE causes some new and interesting behaviors, which are not observed in macro scale. Some of them are anisotropic gas pressure, gas diffusion due to size and geometry differences, thermosize effects like thermoelectric effects and the disappearance of the additivity property of extensive quantities. In literature, the dependence of TP of gases on the shape and size of the confinement domain have recently been examined for the global properties only. These studies consider only rectangular, cylindrical and spherical geometries with a single domain, for which the analytical solution of the Schrödinger equation (SE) is possible, and they are limited with the classical ideal gases obeying Maxwell-Boltzmann statistics. All TP of a system can be calculated when the partition function (PF) is known. PF consists of a summation over the energy eigenvalues of the stationary SE. For macro systems, it is a very good approximation to replace the summation by integration to calculate the PF. For micro/nano systems, however, it is necessary to use a more precise formula (such as Poisson, Euler-Maclaurin or Abel-Plana formula). The precise calculation of the PF is the key work in determining the QSE on TP of small systems. A complete analytical solution of the stationary SE is possible only for a rectangular domain. Even for spherical and cylindrical domains, some approximations should be made to obtain an analytical expression for the energy eigenvalues. For a domain of an arbitrary shape, it is impossible to solve the SE and find the eigenvalues. Fortunately, Weyl's conjecture gives a precise formula for an asymptotic behavior of the eigenvalue spectrum of the stationary SE. Therefore, it is possible to determine the density of states of eigenvalue spectrum in an asymptotic form for a domain of an arbitrary shape. Consequently, the influence of the confinement geometry on the global TP of an ideal gas can be generalized by using the Weyl's conjecture.… [ABSTRACT FROM AUTHOR]

There are various processes for production of turbine blades. Hot forging has been the most common, especially for automotive, marine and industrial turbochargers or aero-engines turbines. Advanced computer modelling has become a powerful tool for process planning and tool design in order to get near-net shape blades in hot forging. This paper presents the effect of die cavity positioning on metal flow and distribution of lateral forces in the die during aero-engine turbine blade hot forging. An influence of torsional moment on dies offsetting introduced by these lateral forces has also been pointed out. [ABSTRACT FROM AUTHOR]

Flat plate systems are commonly designed as a gravity-force-resisting system (GFRS) along with stiffer lateral-force-resisting systems (LFRS) such as shear walls, and moment resisting frames; however, deformation compatibility between the GFRS and LFRS results in positive moments (producing tension at the slab bottom) at the slab-column connections in flat plate systems. Continuous slab-bottom reinforcement (integrity reinforcement) passing through the column is required to prevent progressive collapse; however, for posttensioned flat plate (PT-flat plate) systems, there have been arguments among engineers on applying continuous slab-bottom reinforcement since ACI 318 and 352 provisions do not clearly specify the requirement on the slab-bottom reinforcement for PT flat plates. The purpose of this study is to investigate the effects of continuous slab-bottom reinforcement passing through the column core on the hysteretic behavior of the PT slab-column connections. Test results for six, 3/5 scaled specimens for interior PT flat plate connections subjected to constant gravity loads and quasistatic reversed cyclic lateral loads are presented and indicate that the slab-bottom reinforcement conforming to ACI-ASCE 352R.1 is not required to prevent collapse, but does significantly improves the hysteretic energy absorption capacity. [ABSTRACT FROM AUTHOR]

In the conventional seismic design methods, heightwise distribution of equivalent seismic loads seems to be related implicitly on the elastic vibration modes. Therefore, the employment of such a load pattern does not guarantee the optimum use of materials in the nonlinear range of behavior. Here a method based on the concept of uniform distribution of deformation is implemented in optimization of the dynamic response of structures subjected to seismic excitation. In this approach, the structural properties are modified so that inefficient material is gradually shifted from strong to weak areas of a structure. It is shown that the seismic performance of such a structure is better than those designed conventionally. By conducting this algorithm on shear-building models with various dynamic characteristics, the effects of fundamental period, target ductility demand, number of stories, damping ratio, postyield behavior, and seismic excitations on optimum distribution pattern are investigated. Based on the results, a more adequate load pattern is proposed for seismic design of building structures that is a function of fundamental period of the structure and the target ductility demand. [ABSTRACT FROM AUTHOR]

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The pile-to-cap connection is a critical region in the structure that may experience inelastic behavior during severe earthquake ground motions. Although timber piles are extensively used in construction, little research has been devoted to studying the behavior of timber pile-to-cap connections under cyclic lateral loading, or to develop an improved understanding of the seismic design requirements of these connections. This paper presents an experimental investigation to assess the strength capability of timber pile-to-cap connections. The experimental study was conducted on full-scale timber specimens with different embedment lengths of the pile into the concrete beam. On the basis of the experiments, a theory to predict the lateral capacity of such connections was developed. The study highlighted the significance of wood compression perpendicular to the grain, wood hardness, and embedment length of pile into cap in evaluating the performance of such connections under lateral loads. [ABSTRACT FROM AUTHOR]

Current reinforced masonry wall construction design practice in residential gable ends was reviewed for compliance with the Standard Building Code and ASCE 7-93 wind provisions. The investigation team reviewed 31 residential structures built in the state of Florida after Hurricane Andrew (1992) and before adoption of the Florida Building Code (2002). The existing bracing techniques used to support the gable-end wall were found inadequate to resist wind-induced suction forces defined according to the applicable building codes. The controlling parameters were the spacing of reinforcing pilaster columns and the methods of lateral support along the top of the masonry wall system. The investigation led in part to revisions in the Florida Building Code with respect to the lateral bracing of gable-end wall systems. [ABSTRACT FROM AUTHOR]

This paper examines an ethical dilemma related to the residential construction industry in Florida, where homes must be engineered to withstand extreme load conditions induced during high wind events. Overwhelming contractor pressure to minimize construction costs has resulted in the propagation of inadequate construction designs. The overwhelming adoption of these inadequate designs weakens the integrity of our industry, creating the impression that market pressure can influence our judgment despite conflicting results gained through engineering analysis. This paper illustrates the frailty of engineering judgment as a design fundamental. Further, it raises the question as to what extent professional engineers should substitute engineering judgment for concrete evidence such as numerical analysis or experimental verification. [ABSTRACT FROM AUTHOR]

Lateral strengths required to avoid dynamic instability of single-degree-of-freedom systems are examined. Oscillators with a bilinear hysteretic behavior with negative postyield stiffness are considered. Mean lateral strengths normalized by the lateral strength required to maintain the system elastic are computed for systems with periods ranging from 0.2 to 3.0 s when subjected to 72 earthquake ground motions recorded on firm soil. The effect of the period of vibration and postyield stiffness are investigated. Results indicate that mean normalized lateral strengths required to avoid dynamic instability decrease as negative postyield stiffness increases and that the reductions are much larger for small negative postyield stiffness than for severe negative postyield stiffnesses. It is concluded that there is a significant influence of the period of vibration for short-period systems and for systems with mildly negative postyield stiffnesses. Dispersion of normalized lateral strengths required to avoid dynamic instability are found to increase as the negative postyield stiffness decreases and as the period of vibration increases. Simple equations that capture the effects of period and postyield stiffness to aid in the evaluation of existing structures are obtained through nonliner regression analyses. [ABSTRACT FROM AUTHOR]

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