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The power on gear shift control of a parallel hydraulic hybrid vehicle (PHHV) is researched in this paper. A multibody dynamic model is built to capture the main vibration characteristics of PHHV powertrain, based on which the power on gear shift control strategy is designed and verified. To avoid the vehicle driving torque interruption during gear shift, power on gear shift control strategy is designed. In the control strategy, hydraulic pump/motor (HPM) compensates the engine torque when the engine clutch is disengaged for gear shift. The engine clutch engagement process is carefully controlled by LQR control strategy to mitigate the vehicle powertrain vibration and improve the vehicle driving comfort. Extended Kalman filter (EKF) is adopted to estimate the PHHV parameters required by LQR control. The available HPM torque depends on its working pressure which varies a lot with different accumulator state of charge. So the HPM torque compensation capability is investigated by analysing the traction force requirement during gear shift. To obtain the gear shift traction force demand, a gear shift schedule considering both vehicle fuel economy and dynamic performance is designed. The simulation results show that the HPM could satisfy most of the torque compensation requirements during gear shifts with the designed gear shift schedule in typical driving cycles.

Alignment of femur fractures requires high precision in the presence of a huge traction force which is very arduous. The difficulties are mainly due to the bone’s elongated anatomy and its strong counteracting muscles, which necessitate a high traction force to be exerted by the surgeon and the medical team. Robossis eliminates the need for the surgeon to apply this force, and significantly improves the precision of the procedure. This platform will balance the accuracy, payload, and workspace for the surgeon, resulting in more efficient, successful surgeries. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired reduction steps against the large muscular payloads with high accuracy.

Summary: As an essential step for brain morphogenesis, neurons migrate via mechanical interactions with components of their environment such as neighboring cells and the extracellular matrix. However, the molecular mechanism by which neurons exert forces on their environment during migration remains poorly understood. Here, we show that shootin1b is expressed in migrating mouse olfactory interneurons and accumulates at their leading process growth cone. We demonstrate that shootin1b, by binding to cortactin and L1-CAM, couples F-actin retrograde flow and the adhesive substrate as a clutch molecule. Shootin1b-mediated clutch coupling at the growth cone generates traction force on the substrate, thereby promoting leading process extension and subsequent somal translocation of olfactory interneurons. Furthermore, loss of shootin1 causes abnormal positioning of the interneurons and dysgenesis of the olfactory bulb. Our findings indicate that shootin1b plays a key role in force-driven leading process extension, which propels the migration of olfactory interneurons during olfactory bulb formation. : Minegishi et al. use gene knockout, protein interaction assays, force microscopy, speckle imaging, and migration assays to analyze the molecular mechanics driving neuronal migration in vivo. Their data demonstrate that shootin1b mediates a mechanical clutch to produce force for the migration of olfactory interneurons in the brain. Keywords: neuronal migration, olfactory bulb, interneuron, leading process, growth cone, shootin1, L1-CAM, clutch molecule

© 2015 COSPAR. The dual-reciprocating drill (DRD) is a biologically-inspired concept which has shown promise in planetary environments, requiring a lower overhead force than traditional rotary drilling techniques. By using two reciprocating backwards-facing teethed halves to grip the surrounding substrate, it generates a traction force that reduces the required overhead penetration force. Research into DRD has focused on the effects of operational and substrate parameters on performance compared to static penetration, with minimal study of the geometrical parameters which define the drill head. This paper presents the exploration of the effects of drill head design on drilling depth and power consumption. Sixteen variations of the original design were tested in planetary regolith simulants up to depths of 800. mm. The experiments showed relationships between final depth, total drill radius and cone shape, though the teeth design had a negligible effect on performance. These results can be used alongside the previous research to optimise the future design and operation of the DRD. Drill stem bending was seen to cause an increase in drilling speed and depth, leading to the exploration of the mechanics of diagonal drilling. This resulted in the proposal of a fully-integrated system prototype that incorporates both reciprocating and lateral motion mechanisms.

Numerous techniques for determining the flexibility of the scoliotic cure have been invented. Our contribution includes combining traction and translation forces; we introduced a new radiographic technique that can be claimed to be capable of a far more precise prediction of the scoliotic curve flexibility.In this study, we compared the flexibility rate obtained on standard fulcrum bending radiographs with modified ones in 50 consecutive patients with adolescent idiopathic scoliosis (78 curves) who had referred to our clinics from September 2009 to July 2012. In this new technique, we added traction force to the upside extremities. Then, flexibility rate of the two methods was compared statistically.The study included 50 cases (43 female and 7 male) aged 10-17 (14.5 ± 2.1 years) comprising 78 scoliotic curves. Curves magnitude varied from 25° to 135° (61.4° ± 21.3°). The mean flexibility rate with standard fulcrum bending radiograph was 38.8% ± 20%. This index increased to 58.3% ± 22.2% (which is statistically significant, p 0.0005) as a result of implementing the modified fulcrum bending method. Excluding the proximal thoracic curves due to the limited number of the cases, the difference between flexibility rate with this new technique in main thoracic and thoracolumbar/lumbar curves is not statistically significant (p 0.05).The modified fulcrum bending method we introduced has some inevitable disadvantages; however, in the era of modern and vigorous segmental spinal instrumentation, with combining traction and translation forces in their best biomechanical state, it can demonstrate the scoliotic curve flexibility much more efficiently.

This chapter highlights the use of biological microelectromechanical systems (BioMEMS) to better understand the physical and chemical interactions that cells have with their surroundings. These tools have provided significant insights into the cues from a cell's microenvironment and how they affect cell function. This information is useful in the design and development of new biomaterials and tissue-engineered constructs. BioMEMS devices and techniques are tools that are well-suited for a researcher to examine cell cytoskeleton and traction forces. Additionally, many of the tools presented can also be used to transmit forces to the cell in examining biochemical or biomechanical response. Measurement tools include membrane wrinkling, traction force microscopy, elastomer micropost arrays, extracellular matrix patterning. Micromanipulation techniques include traction force microscopy, magnetic twisting cytometry, optical traps and stretchers, and traditional MEMs fabricated tools. This chapter also covers microfluidic systems to exert physiologically relevant forces such as hemodynamic or interstitial shear forces to better match cell environments in living tissue. Increasingly, researchers have discovered that mechanical forces influence cell behavior in profound ways, and a better understanding through BioMEMS devices is important for future technology and therapy development.

The study of traction forces generated by rapidly moving cells requires the use of substrates that are highly elastic because these cells typically generate weaker traction forces than slower moving cells. Gelatin substrates are soft enough to allow deformation by rapidly moving cells such as fish epidermal keratocytes and Dictyostelium discoideum amoebas. In addition, gelatin substrates are thin (∼30–40μm) and transparent, allowing them to be used in combination with high‐resolution calcium imaging. Importantly, the responsiveness of gelatin substrates allows changes in traction force generation to be detected within seconds, corresponding to the timescale of calcium transients. Here we describe the manufacture and application of gelatin substrates to study the role of mechanochemical signaling in the regulation of keratocyte movement. We show how patterns of traction force generation can be analyzed from a time series of traction vector maps, and how to interpret them in relation to cell movement. In addition, we discuss how the gelatin traction force assay is being used to study the mechanics of Dictyostelium cell motility, and future applications such as the study of neuronal path finding.

A model has been developed to, predict the wear of railway wheels. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Tγ , where T is tractive force and γ is slipt at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. The modelling code is interfaced with ADAMS/Rail, which produces multi-body dynamics simulations of a railway wheelset and contact conditions at the wheel/rail interface. Simplified theory of rolling contact is used to discretise the contact patches produced by ADAMS/Rail and calculate local traction and slip. The wear model combines the simplified theory of rolling contact, ADAMS/Rail output and the wear coefficients to predict the wear and hence the change of wheel profile as the vehicle passes over given track layouts.

Division of Machine Elements, Lulea University of Technology, SE-971 87 Lulea, Sweden The lubricant film thickness in an EHL conjunction has been studied under mixed sliding and rolling conditions using optical interferometry. A hybrid method was developed to combine the experimental study and advanced numerical calculations including a fast algorithm for evaluation of pressure distribution. A multi-channel image analyser was employed to evaluate a 3-D film thickness map. This map was used for calculating pressure distribution by solving the film thickness equation. The influence of sliding on film thickness and its corresponding pressure distribution has been investigated in this paper. The traction force has also measured. The investigations found that at relatively low entrainment velocities the sliding has only a slight influence on the pressure distribution. The characteristic shape of the pressure remains nearly the same for all tested slide/roll ratios. The difference between pressures at various degrees of sliding is seen mostly along the horseshoe shaped constriction. It has also been shown that the lubricant type has influence on the shape of the pressure spike at the outlet.

The paper discusses the tangential deflection between two contacting cylinders. A matrix of influence coefficients is developed that relates point tractive forces to point tangential deflection. The solution is valid for bare cylinders or cylinders containing a surface layer. Microslippage can be reduced by minimizing the traction parameter: F T /fW′, where F T is the traction force, W′ is the normal load and f is the coefficient of friction under slippage conditions. A reasonable value of the traction parameter is 0.2. A soft surface coating tends to increase microslippage. The predictions are compared with experimental measurements for both coated and uncoated cylinders.

Synopsis The determination of power losses and traction forces in modern ball bearings typical of aerospace applications is a complex task. The high rotational speeds commonly experienced by such bearings cause inertia effects to be important, and this inturn loads the balls heavily against the outer raceway of the bearing. The resulting disparity in contact angle tends to introduce a spin component to the motion of the inner raceway/ball contacts on top of the usual sliding and rolling motion. A complete analysis of the contacts would have to include the elastohydrodynamic analysis of heavily loaded contacts, and conjunctions with continuously variable surface velocities. The iterative solution required for such conditions, despite the use of powerful, modern numerical methods, still requires many tens of minutes processing on a large mainframe computer. The computations required for a bearing having 20–30 rolling elements (40–60 contacts) is therefore unreasonable, and even if this were possible its incorporation into the overall dynamic analysis of the bearing would again introduce many more levels of difficulty. For many years the design of bearings for aerospace applications has been based on knowledge gained experimentally, but with the slow introduction of various theoretical work to aid the designer in such calculations as minimum lubricant film thickness. The ever increasing cost of experimental work and the need to make the initial design the best possible, however, provide a requirement for much improved theoretical methods, and hence the need for developments of the type described in this paper. The purpose of the work has been to unite an analysis of bearing dynamics with realistic elastohydrodynamic pressure and film thickness profiles, and then to calculate realistic values for power loss and power transfer within the bearing together with the provision of information on the contact traction forces. A well tried analysis was adopted for calculation of the bearing dynamics, and the use of a simple extrapolation allowed existing solutions to the elastohydrodynamic lubrication problem to be introduced. Calculations of power loss and traction force were then undertaken with the fluid assumed to be either Newtonian or Non-Newtonian, firstly for a single contact and secondly for the whole of an example bearing. The results obtained were then compared with other computations for the same bearing which were known to agree well with the available experimental evidence, and finaly the sensitivity of the analysis to various lubricant parameters was examined. The conclusions drawn from the work were that realistic power loss calculations could be made with a Non-Newtonian fluid model, and that the most important lubricant parameters were the pressure-viscosity coefficient and the limiting-shear-stress-pressure

Publisher Summary This chapter discusses various advantages offered by the application of controlled static converters, mainly in a.c. traction, including the problems encountered with various circuits. The conventional direct-motor drive, that is, the traction motor fed directly from the power supply system through appropriate controls and regulators for speed and tractive force, meets the traction requirements to a fairly high degree. The electric drive should be designed for low maintenance requirements and accessibility to those parts requiring periodic maintenance. The interference of the electrical system with the signaling, telecommunication, and power station installations should require but minor alterations in the fixed installations. The time-honored steam engine already allowed a continuous control of the tractive effort, except for a certain unbalance in the piston forces, and so do the modern diesel locomotives with electric or hydraulic transmission of torque. For the conventional direct-motor fed with a.c. or d.c. from the catenary, the control of the tractive force required a considerable effort that resulted in a quasi-continuous control only. The steps are quite noticeable, even in modern direct-motor designs.

The way cells are organized within a tissue dictates how they sense and respond to extracellular signals, as cues are received and interpreted based on expression and organization of receptors, downstream signaling proteins, and transcription factors. Part of this microenvironmental context is the result of forces acting on the cell, including forces from other cells or from the cellular substrate or basement membrane. However, measuring forces exerted on and by cells is difficult, particularly in an in vivo context, and interpreting how forces affect downstream cellular processes poses an even greater challenge. Here, we present a simple method for monitoring and analyzing forces generated from cell collectives. We demonstrate the ability to generate traction force data from human embryonic stem cells grown in large organized epithelial sheets to determine the magnitude and organization of cell-ECM and cell-cell forces within a self-renewing colony. We show that this method can be used to measure forces in a dynamic hESC system and demonstrate the ability to map intracolony protein localization to force organization.