The effect of collision pulse properties on seven proposed whiplash injury criteria

Recent epidemiological and biomechanical studies have suggested that whiplash injury is related to a vehicle's average acceleration rather than its speed change during a rear-end collision. To further explore this phenomenon, the effect of various kinematic properties of the collision pulse on seven proposed whiplash injury criteria was quantified. A BioRID II rear-impact dummy was seated on a programmable sled and exposed six times to each of 15 different collision pulses. Five properties of the collision pulse were varied: peak acceleration (1.3-4.4 g), speed change (3-11 km/h), duration (52-180 ms), displacement (2-26 cm) and shape (square, sine and triangular). Linear and angular accelerations and displacements of the head, and linear accelerations of the T1 and pelvis were measured in the sagittal-plane. Upper neck loads in the sagittal-plane were also measured. Variations within the proposed injury criteria between the different pulses were compared using analyses of variance. Six criteria--peak upper neck shear force, peak upper neck moment, peak retraction, the neck injury criterion (NIC) and two normalized neck injury criteria (Nij and Nkm)--exhibited graded responses that were most sensitive to the average acceleration of the collision pulse. Peak extension angle between the head and T1 decreased with both increasing speed change and peak acceleration, and was, therefore, deemed unsuitable as a whiplash injury criterion for the BioRID dummy. Of the seven criteria, Nij and Nkm were best able to distinguish between the 15 pulses. If the six graded injury criteria are related to the risk of whiplash injury, then the results of this study indicate that the risk of whiplash injury can be reduced by bumper and seat designs that prolong the collision pulse and thereby reduce the average vehicle and occupant accelerations for a given speed change.     

Morphologie der Einschlüsse bei der Desoxidation mit Aluminium

Erörterung über die Gleichgewichte bei der Desoxidation von Eisenschmelzen mit Aluminium. Desoxidationsversuche mit konvektionsfreien Schmelzen und solchen mit starker Konvektion. Beurteilung der Oxidformen unter dem Lichtmikroskop und Rasterelektronenmikroskop. Darstellung der Abfolge der Wachstumsformen unter verschiedenen Konzentrationsbedingungen. Angaben zum Wachstum aus der Gasphase. Erörterung des Sauerstoffabbaus und der Wachstumsformen sowie von Analogien zu anderen Systemen.     

Wachstumsformen von Aluminiumoxiden in Stählen

Aluminiumoxidformen in Schmelzen mit und ohne Konvektion. Lichtmikroskopische und rasterelektronenmikroskopische Untersuchungen. Einfluß der Sauerstoffaktivität auf das Al₂O₃–Wachstum. Einfluß der Erstarrungsbedingungen auf das Al₂O₃–Wachstum. Stoffstromdichten und Konzentrationen. Konzentrationsverteilungen und Schlieren. Übersättigungen.     

Computer-drawn trajectories of particles in mutual and external fields — An application of computers in university physics teaching

A software system is described which allows the simulation of a large variety of physics phenomena in the computer and the output of results in graphical form. It is designed for interactive use by a class of students working on display terminals. Great care is taken to design the simulation and the display part of the program as flexible as possible. Several examples of simulation are presented and future extensions of the method are discussed.     

Vehicle speed affects both pre-skid braking kinematics and average tire/roadway friction

Vehicles decelerate between brake application and skid onset. To better estimate a vehicle's speed and position at brake application, we investigated how vehicle deceleration varied with initial speed during both the pre-skid and skidding intervals on dry asphalt. Skid-to-stop tests were performed from four initial speeds (20, 40, 60, and 80 km/h) using three different grades of tire (economy, touring, and performance) on a single vehicle and a single road surface. Average skidding friction was found to vary with initial speed and tire type. The post-brake/pre-skid speed loss, elapsed time, distance travelled, and effective friction were found to vary with initial speed. Based on these data, a method using skid mark length to predict vehicle speed and position at brake application rather than skid onset was shown to improve estimates of initial vehicle speed by up to 10 km/h and estimates of vehicle position at brake application by up to 8 m compared to conventional methods that ignore the post-brake/pre-skid interval.     

Ring trial validation of single and multiplex real-time PCR methods for the detection and quantification of the allergenic food ingredients sesame,almond, lupine and Brazil nut

The inter-laboratory (=ring-trial) validation of 4 food allergen quantification methods using real-time PCR is described. Three single real-time PCR methods for the specific detection and quantification of sesame, almond and Brazil nut were used. Additionally, a multiplex real-time PCR method combining the detection of sesame, almond, Brazil nut and lupine was tested in parallel. Matrix based calibrants (rice cookies) spiked (=incurred) with defined amounts of sesame, almond, lupine and Brazil nut were applied for quantitative evaluation. Cookies based upon wheat and rice flour as well as sauce hollandaise powder each incurred with these allergenic ingredients in the range of 10–123 milligram per kilogram were used as ring-trial samples. The lowest spike level of 10 mg/kg could reproducibly be detected by 6 of 7 PCR systems. In quantitative evaluation of the results, reproducibility standard deviations of approximately 50 % and below were obtained. In addition, the effect of the food matrix on allergen quantification was examined. The range of “recoveries” over all matrices and methods was from 43 to 109 %.     

Studying the advancement in debugging practice of professional software developers

In 1997, Henry Lieberman stated that debugging is the dirty little secret of computer science. Since then, several promising debugging technologies have been developed such as back-in-time debuggers and automatic fault localization methods. However, the last study about the state-of-the-art in debugging is still more than 15 years old and so it is not clear whether these new approaches have been applied in practice or not.For that reason, we investigate the current state of debuggingin a comprehensive study. First, we review the available literature and learn about current approaches and study results. Second, we observe several professional developers while debugging and interview them about their experiences. Third, we create a questionnaire that serves as the basis for a larger online debugging survey. Based on these results, we present new insights into debugging practice that help to suggest new directions for future research.     

Key odourants of pressure-cooked hen meat

The volatile aroma compounds of pressure-cooked hen meat isolated by simultaneous distillation-extraction and extraction-high vacuum distillation were investigated by GC/MS and GC-olfactometry. We found out that 2-furfuryl thiol, 3-(methylthio)propanal, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, (E,E)-2, 4-decadienal, 2-methyl-3-furanthiol and 2-ethyl-3,5-dimethyl pyrazine are the most potent odourants of the pressure-cooked hen meat. We assume that aroma-active compounds such as 2,4,6-trimethyltetrahydro-1,3,5-thiadiazine, 3,5-dime-thyl-1, 2,4-trithiolane, 5,6-dihydro-2,4,6-trimethyl-4H-1,3,5-dithiazine and some unknown compounds, which could only be found in extracts obtained by simultaneous distillation-extraction, are artefacts formed during this isolation process.