RC Structures Strengthened by an Iron-Based Shape Memory Alloy Embedded in a Shotcrete Layer—Nonlinear Finite Element Modeling

Shape memory alloys (SMAs) have been widely used in civil engineering applications including active and passive control of structures, sensors and actuators and strengthening of reinforced concrete (RC) structures owing to unique features such as the shape memory effect and pseudo-elasticity. Iron-based shape memory alloys (Fe-SMAs) have become popular in recent years. Use of iron-based SMAs for strengthening RC structures has received attention in the recent decade due to the advantages it presents, that is, no ducts or anchor heads are required, friction losses do not occur and no space is needed for a hydraulic device to exert force. Accordingly, Fe-SMAs embedded in a shotcrete layer have been used for pre-stressing RC beams at Empa. The aim of this study is to present an approach to model and analyze the behavior of RC members strengthened and pre-stressed with Fe-SMA rebars embedded in a shotcrete layer. The lack of research on developing finite element models for studying the behavior of concrete structures strengthened by iron-based shape memory alloys is addressed. Three-dimensional finite element models were developed in the commercial finite element code ABAQUS, using the concrete damaged plasticity model to predict the studied beams’ load–displacement response. The results of the finite element analyses show a considerably good agreement with the experimental data in terms of the beams’ cracking load and ultimate load capacity. The effects of different strengthening parameters, including SMA rebar diameter, steel rebar diameter and pre-stressing force level on the beam behavior, were investigated based on the verified finite element models. The results were compared. The load-displacement response of an 18-m concrete girder strengthened and pre-stressed with iron-based SMA bars was examined by the developed finite element model as a case study.     

Experimental and Numerical Analysis of the Deformation Behavior of Adaptive Fiber-Rubber Composites with Integrated Shape Memory Alloys

Fiber-reinforced rubber composites with integrated shape memory alloy (SMA) actuator wires present a promising approach for the creation of soft and highly elastic structures with adaptive functionalities for usage in aerospace, robotic, or biomedical applications. In this work, the flat-knitting technology is used to develop glass-fiber-reinforced fabrics with tailored properties designed for active bending deformations. During the knitting process, the SMA wires are integrated into the textile and positioned with respect to their actuation task. Then, the fabrics are infiltrated with liquid silicone, thus creating actively deformable composites. For dimensioning such structures, a comprehensive understanding of the interactions of all components is required. Therefore, a simulation model is developed that captures the properties of the rubber matrix, fiber reinforcement, and the SMA actuators and that is capable of simulating the active bending deformations of the specimens. After model calibration with experimental four-point-bending data, the SMA-driven bending deformation is simulated. The model is validated with activation experiments of the actively deformable specimens. The simulation results show good agreement with the experimental tests, thus enabling further investigations into the deformation mechanisms of actively deformable fiber-reinforced rubbers.     

Highly sensitive and selective odorant sensor using living cells expressing insect olfactory receptors

This paper describes a highly sensitive and selective chemical sensor using living cells (Xenopus laevis oocytes) within a portable fluidic device. We constructed an odorant sensor whose sensitivity is a few parts per billion in solution and can simultaneously distinguish different types of chemicals that have only a slight difference in double bond isomerism or functional group such as ─OH, ─CHO and ─C(═O)─. We developed a semiautomatic method to install cells to the fluidic device and achieved stable and reproducible odorant sensing. In addition, we found that the sensor worked for multiple-target chemicals and can be integrated with a robotic system without any noise reduction systems. Our developed sensor is compact and easy to replace in the system. We believe that the sensor can potentially be incorporated into a portable system for monitoring environmental and physical conditions.     

Influence of Vehicle Number on the Dynamic Characteristics of High-Speed Train-CRTS III Slab Track-Subgrade Coupled System

In this paper, a high-speed train–CRTS III slab track–subgrade coupled dynamic model is established. With the model, the influence of vehicle number on the dynamic characteristics of a train–CRTS III slab track–subgrade coupled system with smooth and random track irregularity conditions for conventional and vibration-reduction CRTS III slab tracks are theoretically studied and analyzed. Some conclusions are drawn from the results: (1) the largest dynamic responses of the coupled system for all items and cases are no longer changed when the vehicle number exceeds three, and three vehicles are adequate to guarantee the simulation precision to investigate the dynamic responses of the coupled system. (2) The acceleration of the car body has almost no relation with the vehicle number, and only one vehicle is needed to study the vehicle dynamics using the train–CRTS III slab track–subgrade coupled dynamic model. (3) For the conventional CRTS III slab track on a subgrade, the vehicle number has a negligible influence on the accelerations of the rail, slab, and concrete base, the positive and negative bending moments of the rail, the compressive force of the fastener, and the positive bending stress of slab, but it has a large influence on the tension force of the fastener, and the negative bending stresses of the slab and concrete base. Only one vehicle is needed to study track dynamics without considering the tension force of the fastener, the negative bending stresses of the slab and concrete base, otherwise, two or more vehicles are required. (4) For vibration reduction of the CRTS III slab track on a subgrade, the number of vehicles has some influence on the dynamic responses of all track components, and at least two vehicles are required to investigate the track dynamics.     

A small pliable humidity sensor, with special reference to the prevention of decubitus ulcers.

In an investigation of some of the external causes of decubitus ulcer, a small flexible sensor has been developed as a clinical device to measure the relative humidity (RH) of the environment between the patient and the surface on which he lies. The sensor (described in detail) can indicate RH in the range of 20 to 90 per cent by a color-matching method (chemically impregnated circles); accuracy is within 5 to 10 percent. In a preliminary study on 28 patients, the readings showed that RH was higher in the sacral region than in the scapular region, and higher for patients who were inactive than for those who were active. The device was well accepted by both patients and nurses.     

Active Vibration Control of Piezoelectric Sandwich Plates

This paper deals with the active vibration control of piezoelectric sandwich plate. The structure consists of a substrate plate layer sandwiched between two layers of piezoelectric sensor and actuator. Based on laminate theory and constitutive equation of piezoelectric material, the vibration active control dynamic equation of the sandwich structure is established by using hypothetical mode method and Hamilton principle. The Rayleigh-Ritz method is used to solve it. The form of hypothetical solution is used for approximate solution, which is simple and accurate. The method of this paper is verified by several examples. The parametric studies of the sandwich plate structures are carried out. The results show that applying different boundary conditions and piezoelectric patch positions to the structures have a great influence on the natural frequency. When the driving voltage increases, the deflection of the plate structures increase approximately linearly. The active vibration control studies are investigated as well. The results show that within a certain range, the larger the value of the speed feedback coefficient, the better the active control effect. The positions of the piezoelectric patches affect the effectiveness and cost of active control. When the piezoelectric plate is located at the fixed end, the effect and cost of active control are better than that at the midpoint and free end of the plate.     

Preventing pediatric cardiothoracic trauma: Role of policy and legislation

Data from the last 50 years suggest that pediatric pa-tients typically suffer cardiothoracic injuries following blunt traumatic force(70%) in the setting of either motor vehicle crashes(53.5%) or vehicle-pedestrian accidents(18.2%). Penetrating trauma accounts for 30% of pediatric cardiothoracic injuries, half of which are gunshot wounds. Graduated driver licensing progr-ams, gun-control legislation, off-road vehicle regulation, initiatives such as "Prevent the Bleed", as well as prof-essional society recommendations are key in preventing pediatric cardiothoracic injuries.     

Motor vehicle crash characteristics and medical outcomes among older drivers in Utah, 1992-1995

STUDY OBJECTIVE: We sought to compare the characteristics and medical outcomes of motor vehicle crashes for drivers 70 years and older with those of drivers between the ages of 30 and 39 years. METHODS: We probabilistically linked statewide motor vehicle crash and hospital discharge data between the years of 1992 and 1995 for the state of Utah. We calculated the odds of older drivers exhibiting certain motor vehicle crash characteristics compared with younger drivers. Adjusting for nighttime crash, high-speed crash, and seatbelt use, we calculated the odds of an older driver being killed or hospitalized compared with those of a younger driver. RESULTS: During the study years, there were 14,466 drivers older than 69 years and 68,706 drivers between the ages of 30 and 39 years involved in motor vehicle crashes in Utah. Older drivers were less likely to have crashes involving drug or alcohol use (odds ratio [OR] 0.1; 95% confidence interval [CI] 0.1 to 0.2) and less likely to have crashes at high speed (OR 0.6; 95% CI 0.6 to 0.7). Although older drivers were no more likely to have a crash involving a right-hand turn (OR 1.0; 95% CI 0.9 to 1.1) than younger drivers, they were over twice as likely to have a crash involving a left-hand turn (OR 2.3; 95% CI 2.2 to 2.5). Also, older drivers were more likely to be killed or hospitalized than younger drivers (OR, 3.5; P <.001). Among belted drivers, an older driver was nearly 7 times more likely to be killed or hospitalized than a younger driver (OR 6. 9; 95% CI 5.4 to 8.9). CONCLUSION: Older drivers do have distinctive motor vehicle crash patterns. Interventions must be taken to reduce the number of left-hand turn crashes involving older drivers. In addition, further research is needed to design, implement, and evaluate countermeasures that may enable older drivers to continue driving while keeping public safety in the forefront.     

From the Cover: Sniffing enables communication and environmental control for the severely disabled

Paradoxically, improvements in emergency medicine have increased survival albeit with severe disability ranging from quadriplegia to “locked-in syndrome.” Locked-in syndrome is characterized by intact cognition yet complete paralysis, and hence these individuals are “locked-in” their own body, at best able to communicate using eye blinks alone. Sniffing is a precise sensory-motor acquisition entailing changes in nasal pressure. The fine control of sniffing depends on positioning the soft palate, which is innervated by multiple cranial nerves. This innervation pattern led us to hypothesize that sniffing may remain conserved following severe injury. To test this, we developed a device that measures nasal pressure and converts it into electrical signals. The device enabled sniffs to control an actuator with speed similar to that of a hand using a mouse or joystick. Functional magnetic resonance imaging of device usage revealed a widely distributed neural network, allowing for increased conservation following injury. Also, device usage shared neural substrates with language production, rendering sniffs a promising bypass mode of communication. Indeed, sniffing allowed completely paralyzed locked-in participants to write text and quadriplegic participants to write text and drive an electric wheelchair. We conclude that redirection of sniff motor programs toward alternative functions allows sniffing to provide a control interface that is fast, accurate, robust, and highly conserved following severe injury.     

Integrated Temperature and Position Sensors in a Shape-Memory Driven Soft Actuator for Closed-Loop Control

Soft actuators are a promising option for the advancing fields of human-machine interaction and dexterous robots in complex environments. Shape memory alloy wire actuators can be integrated into fiber rubber composites for highly deformable structures. For autonomous, closed-loop control of such systems, additional integrated sensors are necessary. In this work, a soft actuator is presented that incorporates fiber-based actuators and sensors to monitor both deformation and temperature. The soft actuator showed considerable deformation around two solid body joints, which was then compared to the sensor signals, and their correlation was analyzed. Both, the actuator as well as the sensor materials were processed by braiding and tailored fiber placement before molding with silicone rubber. Finally, the novel fiber-rubber composite material was used to implement closed-loop control of the actuator with a maximum error of 0.5°.     

Abrasive Waterjet (AWJ) Forces—Indicator of Cutting System Malfunction

Measurements enabling the online monitoring of the abrasive waterjet (AWJ) cutting process are still under development. This paper presents an experimental method which can be applicable for the evaluation of the AWJ cutting quality through the measurement of forces during the cutting process. The force measuring device developed and patented by our team has been used for measurement on several metal materials. The results show the dependence of the cutting to deformation force ratio on the relative traverse speed. Thus, the force data may help with a better understanding the interaction between the abrasive jet and the material, simultaneously impacting the improvement of both the theoretical and empirical models. The advanced models could substantially improve the selection of suitable parameters for AWJ cutting, milling or turning with the desired quality of product at the end of the process. Nevertheless, it is also presented that force measurements may detect some undesired effects, e.g., not fully penetrated material and/or some product distortions. In the case of a proper designing of the measuring device, the force measurement can be applied in the online monitoring of the cutting process and its continuous control.     

Valveless microliter combustion for densely packed arrays of powerful soft actuators

Existing tactile stimulation technologies powered by small actuators offer low-resolution stimuli compared to the enormous mechanoreceptor density of human skin. Arrays of soft pneumatic actuators initially show promise as small-resolution (1- to 3-mm diameter), highly conformable tactile display strategies yet ultimately fail because of their need for valves bulkier than the actuators themselves. In this paper, we demonstrate an array of individually addressable, soft fluidic actuators that operate without electromechanical valves. We achieve this by using microscale combustion and localized thermal flame quenching. Precisely, liquid metal electrodes produce sparks to ignite fuel lean methane–oxygen mixtures in a 5-mm diameter, 2-mm tall silicone cylinder. The exothermic reaction quickly pressurizes the cylinder, displacing a silicone membrane up to 6 mm in under 1 ms. This device has an estimated free-inflation instantaneous stroke power of 3 W. The maximum reported operational frequency of these cylinders is 1.2 kHz with average displacements of ∼100 µm. We demonstrate that, at these small scales, the wall-quenching flame behavior also allows operation of a 3 × 3 array of 3-mm diameter cylinders with 4-mm pitch. Though we primarily present our device as a tactile display technology, it is a platform microactuator technology with application beyond this one.

Through the senses, human beings constantly gain rich information about the external world; ultimately, everything one knows comes from what one first learns through one’s sense powers (1). Though sight is generally considered to be our strongest sensorial asset, touch (pressure, pain, vibration, temperature, etc.) intimately connects us with our nearby environment and our own bodies. Touch is, perhaps, more necessary for survival than any other sense (2–8). It is unsurprising, then, that our skin is our bodies’ largest organ (9, 10), comprising in part a diverse array of mechanoreceptive organelles, allowing people to feel skin deformations of different types, durations, and intensities (11). For example, human fingertips have over 200 mechanoreceptive units per square centimeter (10), perceiving static deformations of down to 0.1 mm (12) and vibrations of up to 400 Hz (10, 13).Despite the importance of touch, our visual and auditory senses dominate the experience of digital information. The most proliferate form of haptic actuation is vibrotactile, but this technique does not allow the type of displacement and persistence of touch required to provide a natural experience. Vibrations alone cannot meaningfully recreate the pressure felt from a bag on the shoulders or the impact of a ball caught in the hands. Because of this lack of haptic experience, at least two societal needs remain unfulfilled: artificial touch recreation in immersive virtual reality (VR) and braille displays that compete with analogous visual media. For braille, specifically, there are no full-page, affordable, portable, refreshable displays on the market (14).The dearth of available tactile display options is not from lack of trying; manufacturing arrays of actuators at the size and density suitable for reading computer information from a tactile screen requires reducing actuator volume, weight, power draw, and cost, all together. The diverse set of designs conceived to achieve this haptic challenge have employed an equally numerous suite of physical principles, and each actuation method has presented its own failure mode (14). For example, thermal actuators usually take seconds (without thermal management accessories) (15) to finish a work loop because of heat transport limitations (16). Pulsed electromagnetic systems suffer from low actuation forces and interference between individual actuators (crosstalk) when made close to the size of a braille dot (17). Piezoelectric devices have large production costs at scale (HyperBraille systems cost ∼$50,000), also needing long cantilevered geometries that impede their ability to be densely arranged (14, 18).Fluidic elastomer actuators (FEAs) displace rubber forms with liquids and gases, showing promise as dense actuator arrays because of their manufacturing simplicity and favorable mechanical characteristics (19). An elastomeric membrane ∼1 mm in diameter can displace more than 0.5 mm as was previously shown by ref. 20 in which a 1.5-mm diameter viscoelastic membrane displaced 0.56 mm in about 1 s. Beyond simplicity, these soft haptic devices also have the convenient ability to conform to complex body shapes (21). For example, HaptX has developed a commercial, tethered VR glove technology that integrates 130 individually addressable fluidic actuators into each glove (22). This paper’s lead author has experienced this technology and testifies to its natural feel (23). As designed, the glove’s microfluidic channels are tethered to a large box housing a pump and many valves, limiting the user’s range of motion. One major deficiency of FEAs is how the system scales with actuator number density: there is generally a linear relationship between the number of valves and actuators. As electromechanical valves are themselves actuators, the size, weight, power, and cost (SWaP-C) requirements of FEA arrays soon become untenable for portable tactile display systems. For example, the most popular valve choice for FEAs is the Parker X-Valve, with dimensions of 7.87 × 23.37 × 12.30 mm³ at a unit cost of ∼$40 (24); if a single, six-dot braille cell (∼6 × 10 × 10 mm³) was controlled by six valves, that is, one valve per actuator, the array of valves would take up 18.4 times the cell area and cost $240 (14). Though there are multiplexing solutions to the valving challenge (25), we are currently unaware of any high-resolution tactile interaction being enabled by these methods.Counterintuitively, microscale combustion could provide an alternative actuation motif for haptic arrays, given its own engineering tradeoffs. Combining high-energy density fuels (26, 27) with small-volume mechanical elements results in a potentially safe and enduring actuation mechanism. Previously, microscale combustion research primarily focused on replacing batteries with high–power density micro-electromechanical systems (MEMS) thermoelectric generators (28). These systems may have failed to become practical because of unwanted flame extinction, thermal degradation, and frictional wear (29). More recently, combustion has been used in FEAs for macroscale soft robots and pumps (30–34). A spark ignites a combustible gas mixture that rapidly heats the product gas and expands the soft FEA cavity to move a robot or separate fluid. This research direction, however, has not been previously expanded into the realm of small gas-powered FEAs (35).In this paper, we make two contributions: 1) the use of combustion in microliter-scale FEAs for powerful, high-stroke, millimeter-scale actuations and 2) the exploitation of rapid thermal quenching at these scales to individually actuate fluidically coupled arrays without valving. As we no longer need valves, we can space the actuators more closely because their flow and electrical control components occupy less area than the actuator footprint. Primarily composed of molded silicone and microfluidic liquid metal (LM) traces, our design is an inexpensive, thin rubber sheet that provides more favorable SWaP-C scaling than prior FEA systems. We elementally characterize our device’s mechanical performance as a general microactuation strategy. As tactile display systems represent one of the oldest, broadest, and most contemporary microactuator research initiatives, we focus our discussion and demonstration on this system’s potential to serve a similar purpose.     

Experimental Investigation of the Effect of the Driving Voltage of an Electroadhesion Actuator

This paper investigates the effect of driving voltage on the attachment force of an electroadhesion actuator, as the existing literature on the saturation of the adhesive force at a higher electric field is incomplete. A new type of electroadhesion actuator using normally available materials, such as aluminum foil, PVC tape and a silicone rubber sheet used for keyboard protection, has been developed with a simple layered structure that is capable of developing adhesive force consistently. The developed actuator is subjected to the experiment for the evaluation of various test surfaces; aluminum, brick, ceramic, concrete and glass. The driving high voltage is varied in steps to determine the characteristics of the output holding force. Results show a quadratic relation between F (adhesion force) and V (driving voltage) within the 2 kV range. After this range, the F-V responses consistently show a saturation trend at high electric fields. Next, the concept of the leakage current that can occur in the dielectric material and the corona discharge through air has been introduced. Results show that the voltage level, which corresponds to the beginning of the supply current, matches well with the beginning of the force saturation. With the confirmation of this hypothesis, a working model for electroadhesion actuation is proposed. Based on the experimental results, it is proposed that such a kind of actuator can be driven within a range of optimum high voltage to remain electrically efficient. This practice is recommended for the future design, development and characterization of electroadhesion actuators for robotic applications.     

The Tromped: a solution for flight-related deep vein thrombosis?

Flight-related deep vein thrombosis (DVT) is well recognized. Reduced venous return occurs during immobility. This alteration in venous hemodynamics may contribute to DVT development. A prototype design of an in-flight exercise device to stimulate ambulatory bloodflow while seated has been developed, consisting of a foot pedal attached to a base by a hinge mechanism. Four devices of differing resistance were evaluated. Calf muscle pump function was assessed by air plethysmography in 10 healthy volunteers. Ejection volume fraction and RVF were determined in the standing position (control values) and were compared with those achieved by depression of the 4 devices while seated. Similar EVF and RVF values were achieved by the control and 2 of the devices. Plantar flexion against a predetermined resistance can effectively activate the calf muscle pump while seated and may reduce the incidence of flight-related DVT.     

Intermittent claudication: an objective office-based assessment

OBJECTIVES: We sought to compare standard lower extremity vascular laboratory treadmill exercise with the office-based active pedal plantarflexion technique. BACKGROUND: Intermittent claudication is relatively common in elderly patients and is an important predictor of cardiovascular morbidity and mortality. Noninvasive testing using resting and posttreadmill exercise ankle:brachial systolic blood pressure indices is often required to confirm the diagnosis and objectively assess the severity of lower extremity arterial occlusive disease. This is traditionally performed in a formal vascular laboratory setting. METHODS: Fifty consecutive patients (100 lower extremities) with known or suspected intermittent claudication referred for lower extremity treadmill exercise testing were also tested with active pedal plantarflexion using a prospective, randomized crossover design. Supine ankle:brachial systolic blood pressure indices were measured immediately before and after each form of exercise. RESULTS: There was an excellent correlation (r = 0.95, 95% confidence interval 0.93 to 0.97) between mean postexercise ankle:brachial systolic blood pressure indices for treadmill exercise and active pedal plantarflexion. There was no significant difference in outcome based on the order of testing or the severity of arterial occlusive disease. Symptoms of angina or dyspnea occurred in 11 patients (22%) with treadmill exercise versus zero patients with active pedal plantarflexion. CONCLUSIONS: Active pedal plantarflexion is an office-based test that compares favorably with treadmill exercise for the noninvasive, safe, objective and economical assessment of lower extremity arterial occlusive disease.     

去势对大鼠肠系膜小动脉的血管功能影响及其机制研究

目的本研究观察雄激素缺乏对大鼠肠系膜小动脉舒缩功能的影响,以及其是否涉及Rho/Rho激酶（ROCK）信号通路。方法用离体血管张力法检测24周龄对照和去势大鼠的肠系膜小动脉收缩和舒张反应。结果 1）去势组大鼠的肠系膜小动脉对苯肾上腺素（PE）收缩反应较对照组无差异;2）去势组与对照组比较对低浓度（0.01μM）的乙酰胆碱（ACh）、硝普钠（SNP）舒张反应增强（23%±5%vs.5%±3%,28%±7%vs.9%±3%,respectively,P〈0.05）,高度浓度时（10μM）无差别;3）预孵育ROCK抑制剂（Y-27632,1μM）后,较抑制前对照组对PE收缩反应降低（Emax99%±4%vs134%±8%,P〈0.01）,去势组未有改变;两组对ACh反应较抑制前均无差异,两组对浓度依赖的Y-27632舒张反应也无差异。结论去势不影响大鼠肠系膜小动脉的收缩功能,但减弱了其对ROCK的敏感性;去势可增强大鼠肠系膜动脉的内皮和非内皮依赖性舒张,与ROCK无关。     

Two-Way Bending Properties of Shape Memory Composite with SMA and SMP

A shape memory composite (SMC) was fabricated with a shape memory alloy (SMA) and a shape memory polymer (SMP), and its two-way bending deformation and recovery force were investigated. The results obtained can be summarized as follows: (1) two kinds of SMA tapes which show the shape memory effect (SME) and superelasticity (SE) were heat-treated to memorize the round shape. The shape-memorized round SMA tapes were arranged facing in the opposite directions and were sandwiched between the SMP sheets. The SMC belt can be fabricated by using the appropriate factors: the number of SMP sheets, the pressing force, the heating temperature and the hold time. (2) The two-way bending deformation with an angle of 56 degrees in the fabricated SMC belt is observed based on the SME and SE of the SMA tapes during heating and cooling. (3) If the SMC belt is heated and cooled by keeping the bent form, the recovery force increases during heating and degreases during cooling based on the two-way properties of the SMC. (4) The development and application of high-functional SMCs are expected by the combination of the SMA and the SMP with various kinds of phase transformation temperatures, volume fractions, configurations and heating-cooling rates.     

Analysis of recreational off-road vehicle accidents resulting in spinal cord injury

Twelve cases of spinal cord injury (SCI) resulting from recreational off-road vehicle (ORV) accidents seen during a three-year period at a spinal cord injury center were analyzed using structured interviews and record reviews. Seven accidents involved three-wheel all-terrain vehicles (ATVs), one involved a four-wheel ATV, and four involved two-wheel trailbikes. The analysis of accident victim characteristics showed that all age groups are at risk, and that most victims were young adult men vehicle drivers with experience and wearing helmets. Spinal injury levels were cervical, three; thoracic, three; and thoracolumbar, six. Categorized accident hazard patterns were loss of control, six; tipover, four; and hidden obstacle, two. Contributing causative factors to the accident occurrence were poor driver judgment, seven, and vehicle instability, eight. Speeding was the most frequent primary cause of ORV accidents. We discuss vehicle and driver performance characteristics as they relate to risk of accident occurrence. The frequency of ORV accidents as an etiology of traumatic SCI at our center was 8%, compared to 8% for diving accidents and 11% for motorcycle accidents. We recommend, in view of the high risk of severe injury, widespread public education about ORV accident prevention.     

Improving manufacturing of aeronautical parts with an enhanced industrial Robotised Fibre Placement Cell using an external force-vision scheme

Composite materials are increasingly used in the demanding field of aeronautics. To meet this growing need, the company Coriolis Composites has developed an automated fibre placement device already on the market. This process uses an industrial manipulator robot. This fibre placement task requires a compacting strength adapted to the material used. For the robot, the reference trajectories in position of each tape are prescribed off-line. However, accuracy problems of tape placement appear when off-line programmed robot trajectories. The proposed approach to address the accuracy problem and the manufacturing constraints is an interactive manufacturing scheme based on exteroceptive sensor loops. This paper shows an interactive manufacturing approach based on force servoing to control the compacting strength and on visual servoing to control the lateral position of the tape in order to improve the fibre placement accuracy and then the quality of manufactured parts.     

阻塞性睡眠呼吸暂停低通气综合征对机动车驾驶影响的研究现状

阻塞性睡眠呼吸暂停低通气综合征（OSAHS）可损害反应速度、警觉性等认知功能。研究发现OSAHS驾驶员发生机动车事故的机率明显高于非OSAHS驾驶员；经过有效治疗OSAHS患者事故风险回复至非OSAHS人群的水平；商业驾驶员中嗜睡发生率、OSAHS患病率显著高于普通人群。因此，在机动车驾驶人员中，积极预防、发现、诊断和治疗OSAHS，对驾驶员个人健康和安全、对社会交通安全均有重要价值。