Number Of Acceleration Events Research Articles

Risks of Goods Transport Focused on the Assessment of Semi-Trailer Dynamics on Highways for Cargo Securing

The issue of the transport of goods is well-known, yet, in practice, there are often cases of damaged shipments due to improper storage and inappropriately chosen transport technology. Many cases are due to ignorance of the basic characteristics of the cargo and, consequently, its transport characteristics. Vehicle dynamics is crucial to the design of proper cargo securing; therefore, this article provides the values of longitudinal and lateral acceleration of a 16.5 m semi-trailer vehicle combination for test routes of length of 10,827 km on highways and other roads in Slovakia, Austria, and Germany from the monitoring of goods. The horizontal acceleration of 0.2 g is considered as the minimum stability of the load unit that should withstand transport. A load unit with a stability from 0.2 g to 0.3 g could be considered as the weakest load unit. The test results show that even the weakest load units such as these can be damaged in transports, as semi-trailer vehicle combinations still reach longitudinal ax1000 and lateral ay1000 accelerations between 0.2 g and 0.3 g relatively frequently. Acceleration events higher than 0.3 g occur very rarely, at 1.4 event/1000 km for roads, but only 0.1 event/1000 km for highways from our test transports. We have demonstrated through our research that it is necessary for the load units to have a minimum stability of 0.2 g. We can conclude that load units with a stability of less than 0.2 g are completely unacceptable for transport without additional securing because we obtained 70.3 acceleration events per 1000 km in the interval from 0.1 g to 0.2 g on highways but 1148.1 events per 1000 km on other roads. There is a big difference between the number of acceleration events per 1000 km on roads and highways for all acceleration intervals, which means that there is a substantially lower probability of damaging the weak load units on highways than on other roads.

Estimation of aircraft taxi fuel burn using flight data recorder archives

This paper builds a model for estimating the fuel consumption of a taxiing aircraft using flight data recorder information from operational aircraft. The taxi fuel burn is modeled as a linear function of several potential explanatory variables including the taxi time, number of stops, number of turns and number of acceleration events, and the coefficients are estimated using least-squares regression. The statistical significance of each potential factor is investigated. Our analysis shows that in addition to the taxi time, the number of acceleration events is a significant factor in determining taxi fuel consumption. Since the model parameters are estimated using data from operational aircraft, they provide more accurate estimates of fuel burn than methods that use idealized physical models of fuel consumption based on aircraft velocity profiles, or the baseline fuel consumption estimates provided by the International Civil Aviation Organization.

Biomechanical Analysis of Stresses to the Fifth Metatarsal Bone During Sports Maneuvers: Implications for Fifth Metatarsal Fractures

Fifth metatarsal stress fractures are an increasing problem in elite and recreational athletic populations. One possible mechanism of injury is the many bending moments applied to the fifth metatarsal during dynamic sports maneuvers involving rapid changes in direction and speed. A potentially important bending moment is loading of the base versus the head of the fifth metatarsal, which tends to cause a bending moment along the bone. To determine which maneuver applies the greatest pressure differential between the base and head of the fifth metatarsal, 10 college-aged male athletes performed running straight, jump take-off, jump landing, cutting right, cutting left, and accelerating while plantar pressures were recorded using a Pedar insole system (Novel Electronics, Inc., St. Paul, MN). Peak pressure at the fifth metatarsal base was subtracted from the peak pressure at the fifth metatarsal head to obtain the fifth metatarsal pressure differential—a corollary to the bending moment. The greatest fifth metatarsal pressure differential was observed during acceleration maneuvers (20 ± 13.1 N/cm2; P < 0.0001) followed by running straight (11.6 ± 8 N/cm2; P < 0.0008). The other maneuvers had low pressure differentials: jump take-off (4.2 ± 10.6 N/cm2), jump landing (3.7 ± 9.2 N/cm2), cutting left (2.3 ± 4.2 N/cm2), and cutting right (–2.1 ± 10 N/cm2). It appears that acceleration maneuvers may apply the largest bending moments to the fifth metatarsal and could lead to stress fractures. Because fifth metatarsal stress fractures are associated with rapid increases in training volume, reducing the number of acceleration events may be effective in altering the balance between bone resorption and bone formation and reducing stress fracture risk. Careful planning of training programs allowing for adequate rest between intense bouts of exercise involving many acceleration maneuvers may be the best preventative measure.