DISTRIBUTION OF THE NORMAL REACTIONS ON THE QUANTOMOBILE WHEELS

Introduction: The progress of science has made it possible to create new quantum engines (QEs) powered by physical vacuum energy. A QE will generate a vector-based propulsive force, or thrust, applicable to the vehicle body directly, with no transmission required. Traditional cars will be upgraded with QEs and thus converted into quantomobiles. QE thrust application at the point of the vehicle body, hovering above the bearing surface, introduces changes in the traditional diagram of forces acting on the vehicle. Therefore, it is necessary to assess the influence of thrust on the longitudinal stability of the quantomobile. Methods: In the course of the study, we upgraded the diagram of forces acting on the traditional vehicle, by introducing QE thrust (bearing in mind vehicle hovering above the bearing surface). We also developed a corresponding mathematical model for the distribution of the normal reactions on the wheels, taking into account QE placement. Results: Among the developed calculation complexes to perform a qualitative analysis of the influence of force factors on the quantomobile chassis load, a complex representing the longitudinal thrust and the thrust height was distinguished. Discussion: These complexes may serve as the basis of calculation units for more detailed programming, analysis, and synthesis of the design of vehicles with QEs, assessment of the longitudinal stability of the vehicle, optimization of QE placement in the quantomobile body. Example: The method developed is presented using a quantomobile similar to a KamAZ-4326 automobile. Conclusion: The considered diagram of forces acting on a quantomobile, including QE thrust above the bearing surface, shall become generic for force diagrams of quantomobiles with additional thrusters intended to increase the longitudinal stability of the vehicle.

Is There Any Effect of Symmetry on Velocity of the Four Swimming Strokes?

The different characteristics of the four swimming strokes affect the interplay between the four limbs, acting as a constraint to the force produced by each hand and foot. The purpose of this study was to analyze the symmetry of force production with a varying number of limbs in action and see its effect on velocity. Fifteen male swimmers performed four all-out bouts of 25-m swims in the four strokes in full-body stroke and segmental actions. A differential pressure system was used to measure the hands/feet propulsive force and a mechanical velocity meter was used to measure swimming velocity. Symmetry index was calculated based on the force values. All strokes and conditions presented contralateral limb asymmetries (ranging from 6.73% to 28% for the peak force and from 9.3% to 35.7% for the mean force). Backstroke was the most asymmetric stroke, followed-up by butterfly, front crawl, and breaststroke. Kicking conditions elicited the higher asymmetries compared with arm-pull conditions. No significant associations were found between asymmetries and velocity. The absence of such association suggests that, to a certain and unknown extent, swimming may benefit from contralateral limb asymmetry.

STUDY OF AIRFLOW AROUND SHIP WITH RIGID SAIL ARRAY AND POTENTIAL ARRAY PROPULSIVE POWER

An array of rigid sails installed on a large powered ship could provide a viable means to reduce fuel oil consumption (FOC) and emissions by using the power of the wind as a source of supplementary propulsion. This paper describes the study of airflow around a concept ship design fitted with 14 segment rigid sails (SRS) using a virtual wind tunnel software application and also investigates the propulsive force that a fixed sail array could provide using computational fluid dynamics (CFD) analysis.

mDia1 Assembles a Linear F-Actin Coat at Membrane Invaginations To Drive Listeria monocytogenes Cell-to-Cell Spreading

Listeria monocytogenes spreads from one cell to another to colonize tissues. This cell-to-cell movement requires the propulsive force of an actin-rich comet tail behind the advancing bacterium, which ultimately distends the host plasma membrane into a slender bacterium-containing membrane protrusion.

Quantifying Cause-Effect Relations Between Walking Speed, Propulsive Force, and Metabolic Cost

Walking speed is a useful surrogate for health status across the population. Walking speed appears to be governed in part by propulsive force (FP) generated during push-off and simultaneously optimized to minimize metabolic cost. However, no study to our knowledge has established empirical cause-effect relations between FP, walking speed, and metabolic cost, even in young adults. To overcome the potential linkage between these factors, we used a self-paced treadmill controller and real-time biofeedback to independently prescribe walking speed or FP across a range of condition intensities. Walking with larger and smaller FP led to instinctively faster and slower walking speeds, respectively, with about 80% of variance explained between those outcomes. We also found that comparable changes in either FP or walking speed elicited predictable and relatively uniform changes in metabolic cost, each explaining about ~53% of the variance in net metabolic power and ~15% of the variance in cost of transport, respectively. These findings build confidence that interventions designed to increase FP will translate to improved walking speed. Repeating this protocol in other populations may identify additional cause-effect relations that could inform the time course of gait decline due to age and disease.

Ground Reaction Force Differences between Bionic Shoes and Neutral Running Shoes in Recreational Male Runners before and after a 5 km Run

Running-related injuries are common among runners. Recent studies in footwear have shown that designs of shoes can potentially affect sports performance and risk of injury. Bionic shoes combine the functions of barefoot running and foot protection and incorporate traditional unstable structures based on bionic science. The purpose of this study was to investigate ground reaction force (GRF) differences for a 5 km run and how bionic shoes affect GRFs. Sixteen male recreational runners volunteered to participate in this study and finished two 5 km running sessions (a neutral shoe session and a bionic shoe session). Two-way repeated-measures ANOVAs were performed to determine the differences in GRFs. In the analysis of the footwear conditions of runners, bionic shoes showed significant decreases in vertical impulse, peak propulsive force, propulsive impulse, and contact time, while the braking impulse and vertical instantaneous loading rate (VILR) increased significantly compared to the neutral shoes. Main effects for a 5 km run were also observed at vertical GRFs and anterior–posterior GRFs. The increases of peak vertical impact force, vertical average loading rate (VALR), VILR, peak braking force and braking impulse were observed in post-5 km running trials and a reduction in peak propulsive force and propulsive impulse. The interaction effects existed in VILR and contact time. The results suggest that bionic shoes may benefit runners with decreasing injury risk during running. The findings of the present study may help to understand the effects of footwear design during prolonged running, thereby providing valuable information for reducing the risk of running injuries.

DESIGN OF EXPERIMENT FOR SPORTS EQUIPMENT - EXPERIMENTALLY MAPPING THE DESIGN SPACE FOR PARALYMPIC ALPINE OUTRIGGERS

This article presents a design of an experiment for investigating the effect of changing the geometry of Paralympic alpine sit-ski poles/outriggers in the LW 10-12 class. An experiment design for mapping an individual athlete’s performance parameters has been developed, with a resolution for finding the optimal outrigger geometry. By prototyping an adjustable experiment setup with implemented sensor systems, the performance increase can be analysed and implemented in new equipment. Results show that changing double poling geometry provides a substantial performance increase, regarding time and propulsive force.

Aerial course stabilization is impaired in motion-blind flies

Visual motion detection is among the best understood neuronal computations. As extensively investigated in tethered flies, visual motion signals are assumed to be crucial to detect and counteract involuntary course deviations. During free flight, however, course changes are also signalled by other sensory systems. Therefore, it is yet unclear to what extent motion vision contributes to course control. To address this question, we genetically rendered flies motion-blind by blocking their primary motion-sensitive neurons and quantified their free-flight performance. We found that such flies have difficulties maintaining a straight flight trajectory, much like unimpaired flies in the dark. By unilateral wing clipping, we generated an asymmetry in propulsive force and tested the ability of flies to compensate for this perturbation. While wild-type flies showed a remarkable level of compensation, motion-blind animals exhibited pronounced circling behaviour. Our results therefore directly confirm that motion vision is necessary to fly straight under realistic conditions.

Generation of propulsive force via vertical undulations in snakes

Lateral undulation is the most widespread mode of terrestrial vertebrate limbless locomotion, in which posteriorly propagating horizontal waves press against environmental asperities (e.g. grass, rocks) and generate propulsive reaction forces. We hypothesized that snakes can generate propulsion using a similar mechanism of posteriorly propagating vertical waves pressing against suitably oriented environmental asperities. Using an array of horizontally oriented cylinders, one of which was equipped with force sensors, and a motion capture system, we found snakes generated substantial propulsive force and propulsive impulse with minimal contribution from lateral undulation. Additional tests showed that snakes could propel themselves via vertical undulations from a single suitable contact point, and this mechanism was replicated in a robotic model. Vertical undulations can provide snakes a valuable locomotor tool for taking advantage of vertical asperities in a variety of habitats, potentially in combination with lateral undulation, to fully exploit the 3D structure of the habitat.