Collision frontal

Physically the independence reflects the fact that dephasing is performed by weak long-range interactions, and rotational relaxation results mainly from short-range, repulsive forces. In other words the rotational state is changed solely when the distance between molecules becomes rather short, while the phase is frustrated in all cases and the contribution of frontal collisions is not so significant. 

Cantor JO, Adelglass J, Cerreta JM, et al. 1981. Collision tumor of the frontal sinus Evidence of prior intrasinus instillation of thorotrast. Laryngoscope 91 798-803. 

Mixer 92 [M 92] Frontal-collision Impinging Jet Micro Mixer, Microjet Reactor ... 

Figure 1.194 Schematic of a commercial frontal-collision mixer [166] (by courtesy of VDE-Verlag).

Moreover, the comparison of the mixing performance of the grouped mixers 5/6 and 8/9 allows one to judge the influence of the angle a [53]. It was found that the mixing quality at 60° is better than that at 45°. This can be explained by the more frontal collision of the jets at 60°. 

Two arrays of oblique impinging jets in frontal collision and in offset orientation... 

We wish to point out here that the use of a higher order algorithm turns out to be essential for an accurate integration of the motion in contrast to the two-dimensional case where at the same average kinetic energy and number of collisions the Verlet algorithm is sufficiently correct. In our opinion, this is due to the fact that in the one-dimensional case the collisions are always frontal, whereas in the two-dimensional case this kind of colli-... 

Figure 8.23. Heavy ion reactions different types of interaction (schematically) path 1) elastic scattering path 2) quasielastic collision path 3) deeply inelastic collision path 4) frontal collision.

Lastly, it may seem somewhat bizarre to associate a safety device with an explosion but this is the method used to inflate air bags (Figure 1.2), If a vehicle is involved in a frontal collision equivalent to hitting a brick wall at more than 12 to 15 miles per hour, then sensors detect the sudden deceleration and trigger an electrical device which detonates a mixture containing about 65 g of sodium azide (NaN3). The azide undergoes a relatively slow type of explosion... 

Wagstrom, L., Thomson, R. Pipkom, B. 2005. Structural adaptivity in frontal collisions Implications on crash pulse characteristics. International Journal of Crashworthiness 10(A), 371-378. 

Cadavers. Human cadavers have also been used for experiments involving potentially injurious stimuli, and in particular to relate skull fracture to frontal head impact. Such studies resulted in the formulation of the Wayne State concussion tolerance curve, which has been widely used to define survivable head impacts in motor vehicle collisions (SAE J885, 1986). Cadavers lack appropriate mechanical properties for tissues and muscle tension. The latter is important for obtaining redistic human responses, as can be seen from Fig. 10.12 by comparing the results with and without active muscle behavior. 

An example of the use of the MADYMO model to simulate air bag inflation and occupant response to the frontal collision of an automobile is shown in Fig. 10.13. In this diagram, the response of a person wearing a shoulder and lap seat belt has been calculated at 25-ms time intervals following the initiation of air bag inflation. The forward rotation of the head is clearly visible and is arrested before it impacts the chest. Also, the flailing of the arms can be seen. 

FIGURE 10.13 MADYMO simulation of the response of a person wearing a shoulder and lap seat belt to the inflation of an air bag in a frontal motor vehicle collision. The model predicts the body position every 25 ms after the collision. Note the time for the air bag to inflate (between 25 and 50 ms), the rotation of the head, the flailing of the arms, and the bending of the floor. (AGARD-Aft-330,1996.)... 

A type of vehicle restraint system that consists of inflatable bags monnted in the interior of a vehicle that automatically inflate npon a collision to protect the occn-pants from injury. They are designed for frontal impact crashes. This type of crash accounts for more than half of all passenger vehicle occupant deaths. Air bags are designed to limit head and chest injnries. They are considered only supplemental to safety belts they do not replace them. 

One example of a component-based testing method is the Vehicle Related Pedestrian Safety Index (VERPS) [73, 74]. This index utilizes a linear scale for both active and passive safety measures. The pedestrian head impact in frontal passenger vehicle collisions is assessed using the Head Injury Criterion (HIC) as metric. The method delivers specific results for a given vehicle and pedestrian combination. The evaluation process includes accident data analysis for relevant scenarios, kinematic analysis (via multi-body simulation), hardware component testing, and a procedure to obtain the VERPS index [73, 74]. The VERPS index takes only the probability for AIS3+ head injuries due to impact on the vehicle into account, since this probability can be derived from the HIC measurement. 

An advantages of the VERPS method is that both active and passive safety can be asses sedona common linear scale. A drawback is that only pedestrian head injuries in primary frontal passenger vehicle collisions are evaluated, while secondary impacts are not taken included [73, 74]. 

Data were filtered for frontal vehicle impacts with a pedestrian of age four and older, resulting in 450 collisions. In the following analysis, only cases with impact speed available were considered (see above), resulting in 369 collisions. 

Frontal Impact When a vehicle mns into a fixed object or another vehicle in a frontal collision, there is a sequence of events that takes place within a fraction of a second. The amount of force at any point behind the point of impact goes down with distance depending on the amount of energy absorbed in the crash. 

Fig. 32 illustrates in a schematic form the forces acting on the windshield of a bus in an oblique frontal collision. The following sample calculation shows how the safety factor is estimated. 

Figure 32 Stresses acting on the adhesive bond of a bus windshield in an oblique frontal collision with a stationary obstacle.

Such cryogenic systems are interesting not only because of the novel propagation mechanism but also because they may provide insight into how complex molecules were generated in the universe. Simple molecules could have been irradiated with cosmic rays and then caused to react by collisions of meteoroids. Frontal cryopolymerization may also be a method to prepare composites on the Moon and/or Mars [46]. 

Since 1998 aU cars sold in the United States have heen required to have driver and passenger air bags. Research by the U.S. Department of Transportation shows that air bags reduce the risk of death in a frontal collision by about 30%. An air bag plus wearing lap and shoulder belts reduces the likelihood of moderate injury in front-end crashes by about 60%. 

Some order of magnitude of safe crash speeds has been adopted to guide our thoughts (Tingvall and Haworth, 1999). These should not be faster than 30 km/h for crashes between passenger cars and pedestrians/cyclists, while a safe maximum speed for lateral (side impact) collisions between passenger cars at intersections is 50 and 70 km/h for frontal (head on) crashes. 

Almost since its introduction the effectiveness of the air bag has been questioned, let alone its cost-effectiveness. Kent et al. (2005) wrote an extensive review of the various evaluations that were conducted on different versions in its evolution. Early projections were that it alone (without belts) would reduce fatalities in frontal impacts by as much as 57 percent, but as data accumulated the estimates were revised downward to 22-29 percent for frontal collisions and 12-14 percent in all crashes (Kent et ah, 2005). With respect to injury reduction, the benefits are less clear-cut and some, on the basis of analyses of U.S. crash data (Evans, 2004 McGwin et al, 2003) question their effectiveness at all. Finally, However, Thompson et al. (2002), using the revised levels of effectiveness concluded that not only does it save lives and reduce injuries, but in terms of cost/beneflt ratio, the air bag is a reasonable investment in safety . 

A different approach is used by the U.S. Insurance Institute for Highway Safety (IIHS) and tiie European New Car Assessment Program (EuroNCAP). In their simulations of frontal collision the crash barrier only extends into 40 percent of the vehicle s width from the driver side, and the impact speed is 40 mph (64.4 km/h). In partial overlap, the force is distributed over a... 

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