Obtaining quality DNA profiles from firearms can be instrumental in assisting criminal investigations. Typically, swabbings of firearms for handler's DNA are conducted on specific regions of the firearm prior to submission to the laboratory for analysis. This review examines and compares 32 cases whose gun swabbings were either analyzed individually according to the specific region which was swabbed, or analyzed collectively by combining the swabbings from all the individual areas. Those firearms whose swabs were analyzed separately exhibited lower DNA yields and consequently fewer loci exhibiting genotypes. Those cases whose swabs were analyzed collectively exhibited higher DNA yields and consequently greater numbers of loci exhibiting genotypes. These findings demonstrate that collective swabbings result in more complete profiles and lead to the recommendation that a firearm be swabbed in its entirety using no more than two swabs.

Today, numerical simulation is used all over the world to develop and optimise the restraint system performance. But more than just helping engineers to design restraint systems fulfilling the homologation and ratings requirements, the numerical simulation enables them to extend their field of investigation by going beyond the laboratory test conditions, making their first steps in "real life safety". This paper presents the simulation of a concept of an adaptive restraint system for the passenger side. Its restraint capacity is continuously adjustable to the occupant, by an airbag whose shape and volume can be varied. In addition to this, the airbag outflow hole characteristics have also been optimised. The performance of this restraint system has been evaluated using the three standard adult dummies (5th, 50th and 95th percentile), each one in various seating positions for both US and Euro-NCAP pulses. The results will be shown with respect to a state-of-the-art restraint system. The design process, starting from the 95th percentile dummy, will be explained as well as the problems encountered during the optimisation process.

The rotordynamic fluid forces acting on a closed type impeller in whirling motion were measured and the influence of the clearance geometry on the stability of the impeller was examined. At small positive whirling speed, the rotordynamic forces acted as destabilizing forces for all casings. A small clearance between the shroud of the impeller and the casing caused large fluid force, but did not change the destabilizing region. Radial grooves in the clearance were effective for reducing the fluid forces and destabilizing region due to the reduction of the circumferential velocity without the deterioration of the pump performance. A rotating phenomenon like a rotating stall of the impeller occurred at low flow rate and the resonance between it and the whirling motion led to a sudden increase in force at the whirling speed ratio of 0.7.

No abstract

No abstract