Aspects of the mechanics of driving nails into wood

For nail driving, some aspects of the effect on penetration of the hammer mass, the speed at impact, the nail size and section shape and the driving direction in relation to the wood grain are reported.A 6 in. long, 0·236 in. dia., round nail was strain gauged to show how the strain in the nail varies with time during an impact.An analysis, which reasonably accounts for the experimental results, is developed for predicting the strain pulse in the nail, the amount of penetration by the nail and its time under strain.Maintaining the same kinetic energy input at each blow, it is found that the larger the initial penetration, the smaller is the further penetration.The effect on penetration depth of the material backing to the piece of wood is reported.The variation of the Euler buckling load with the nail penetration for a specific type of wood and nail dimensions is given.     

Knowledge-based fault localization in debugging

Fault localization in program debugging is the process of identifying program statements which cause anomalous behavior. We have developed a prototype, knowledge-based model of the fault localization process. Novel features of the model include the integration of prototypic and causal reasoning about faults and a recognition-based mechanism for program abstraction. An explicit division of knowledge from the applications, programming, and language domains facilitate model tuning within as well as across applications domains. We describe model structure and performance for a class of faults associated with master file update programs.     

Potential structural material problems in a hydrogen energy system

Potential structural material problems that may be encountered in the three components of a hydrogen energy system—production, transmission/storage, and utilization—have been identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described. An awareness of probable shortages of strategic materials has been maintained in these suggested programs.     

Perichondritis of the ear as a complication of acupuncture

A 54-year-old woman developed pain, tenderness, and swelling at the site where a short acupuncture needle had been placed in the helix of the pinna. Staphylococcus aureus was isolated from this LESION. Which was treated with removal of the needle and intravenously administered nafcillin. The patient recovered completely and had no scarring.     

Subject performance as affected by experimenter expectancy, sex of experimenter, and verbal reinforcement.

Investigated the effect of E-expectancy, sex of E in relation to sex of S, and verbal reinforcement upon S's response rate in a simple motor-performance task, 160 undergraduates assigned to the 16 cells of a 2 * 2 * 2 * 2 factorial. Ss removed glass marbles from a cache and dropped them 1 at a time through holes drilled in a table top. Main effects of sex of S, verbal reinforcement, and E-expectancy were statistically significant. The expected interaction of sex of E, sex of S, and verbal reinforcement was not supported. The finding of E-expectancy as a significant factor adds to the generality of the phenomenon because of experimental conditions which removed the scoring of responses from E, and which substituted a simple motor-performance task for a judgmental one. (French summary) (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)