Classification of higher- and lower-mileage runners based on running kinematics

Background: Running-related overuse injuries can result from the combination of extrinsic(e.g., running mileage) and intrinsic risk factors(e.g.,biomechanics and gender), but the relationship between these factors is not folly understood. Therefore, the first purpose of this study was to determine whether we could classify higher-and lower-mileage runners according to differences in lower extremity kinematics during the stance and swing phases of running gait. I he second purpose was to subgroup the runners by gender and determine whether we could classify higherand lower-mileage runners in male and female subgroups.Methods: Participants were allocated to the "higher-mileage" group(≥32 km/week; n= 41(30 females)) or to the "lower-mileage" group(≤25 km;n= 40(29 females)). Three-dimensional kinematic data were collected during 60 s of treadmill running at a self-selected speed(2.61 ± 0.23 m/s).A support vector machine classifier identified kinematic differences between higher-and lower-mileage groups based on principal component scores.Results: Higher-and lower-mileage runners(both genders) could be separated with 92.59% classification accuracy. When subgrouping by gender,higher-and lower-mileage female runners could be separated with 89.83% classification accuracy, and higher-and lower-mileage male runners could be separated with 100% classification accuracy.Conclusion: These results demonstrate there are distinct kinematic differences between subgroups related to both mileage and gender, and that these factors need to be considered in future research.

Optimizing Dead Mileage in Urban Bus Routes. Dakar Dem Dikk Case Study

This paper studies the buses assignment from their depots to their routes starting points in urban transportation network. It describes a computational study to solve the dead mileage minimization to optimality. The objective of this work is to assign the buses to depots while optimizing dead mileage associated with pull-out trips and pull-in trips. To do so, a new mixed-integer programming model with 0 - 1 variables is proposed which takes into account the specificity of the buses of Dakar Dem Dikk (the main public transportation company in Dakar). This company manages a fleet of buses which, depending on road conditions some buses cannot circulate on some roads of the network. Thus, buses are classified into two categories and are assigned based on these categories. The related mixed-integer 0 - 1 linear program is solved efficiently to minimize the cumulative distance covered by all buses. Numerical simulations on real datasets are presented.

Influencing factors of tourism revenue in Guizhou province

Tourism revenue plays an increasingly essential role in the national economic revenue of Guizhou province,so it is essential to analyze the factors that affect the tourism revenue of Guizhou province.Based on the econometric model,this paper collects the tourism-related data of Guizhou province from 1999 to 2018,and then selects three variables:the number of tourists,rail mileage,and the number of hotels to make assumptions,and then makes a regression analysis.Finally,the conclusion is drawn that the number of tourists and hotels is significantly related to tourism revenue,and the rail mileage negatively regulates the positive impact of tourists on tourism revenue.Based on this,the paper puts forward some suggestions and measures to improve the tourism revenue of Guizhou province.

Dispatching Fuel-cell Hybrid Electric Vehicles Toward Transportation and Energy Systems Integration

With the increasing integration of traditional elec-tric vehicles(EVs),the ensuing congestion and overloading issues have threatened the reliability of power grid operations.Hydrogen has been advocated as a promising energy carrier to achieve low-carbon transportation and energy(trans-energy)systems,which can support the popularization of fuel-cell hybrid EVs(FCHEVs)while enhancing the flexibility of power grids.In this paper,we propose an optimal scheduling framework for trans-energy systems that evaluates the merits of the hydrogen supply chain from water electrolysis,compressed storage and transportation to FCHEV utilization.A detailed FCHEV model is established,and mileage is modeled as a function of the stored electricity and hydrogen mass.A stochastic programming-based scheduling model is formulated,which minimizes the total cost of unit commitment and the hydrogen supply chain.The Dijkstra algorithm is adopted to search the shortest path for hydrogen transportation.Case studies demonstrate that FCHEVs can reduce the operational costs of tran-energy systems and facilitate the accommodation of renewable energy when compared to traditional EVs.Index Terms-Fuel-cell hybrid electric vehicle,hydrogen,mileage model,shortest path search,trans-energy systems.

Single-grain cutting based modeling of abrasive belt wear in cylindrical grinding

A systematic wear model of the cylindrical grinding process with an alumina abrasive belt from the perspective of single grain sliding wear was established in this study.The model consists of three parts:a single cutting force model derived by applying a stress integration method,a single grain wear height analysis based on the wear rate of alumina,and a grinding mileage prediction of multiple grains with Gaussian distributed protrusion heights.Cutting force,single grain wear height and full‐size grinding mileage verification experiments were conducted.The results indicated that the established model was in reasonable agreement with the experimental outcomes,which suggests that this model could be useful in the industry to predict the wear process of abrasive belts.

INFLUENCE OF GEOMETRIC PARAMETERS ON CENTRIFUGAL FAN PERFORMANCE AND ITS SIGNIFICANCE IN AUTOMOTIVE APPLICATIONS

In this paper,the effect of geometrical parameters of centrifugal fan on performance has been presented with a system approach.Often,the operators or the design engineers focus on the immediate requirements of the engine/equipment and they neglect the broader question of how the fan parameters are affecting the equipment.For instance,change in fan angles will change the performance e.g.,airflow rates and efficiency.However,it also affects the contaminants build-up on the blades.Blade angle with higher angle of attack will promote contaminants build-up on blade surfaces,which in turn causes performance degradation and unstable operation.The system approach in fan parameter selection will result in a more reliable system.Significance of other fan parameters is also discussed.We present an experimental setup and validated computational fluid dynamic(CFD)model.Fan power consumption is determined experimentally and compared with the CFD model.Further parametric simulations were carried out to investigate the effect on fan performance.Effect of system resistance,inlet and outlet angle,blade thickness,and no-uniform spaced blades has been described with discussions on industrial relevance.A fan with higher flow rates is desirable to reduce engine temperatures and enhance the durability.However,higher flow rates result in more fan power consumption at a given fan speed.The test results suggest that a fan with higher power coefficient does not affect the vehicle’s mileage significantly.This paper will help design engineers in making informed decision about the interaction between the fans and system,and its effect during the operation.