4,844 research outputs found
Nuclear Weapon Yield Determination through Nano Indentation of Thermally Degraded Automobile Paint
This work investigated the suitability of automotive clearcoat as a nuclear weapon yield sensor, using the change in elastic modulus as the primary metric. The AFIT Xenon Thermal Simulator (AXTS) was used to simulate a nuclear thermal pulse. The elastic modulus of the clearcoat was measured using a nano indenter. During this research the power density of the AXTS beam was increased from 44.7 to 63.7 W/cm2. The morphological steps through which automobile paint proceeds as it thermally degrades were identified and correlated with temperatures. A computer model was created and used to ensure that the paint’s time-temperature response to the AXTS pulse was comparable to that of a replicate nuclear thermal pulse. Clearcoat’s physical properties exhibit a low sensitivity to incident thermal energy. Variability among these properties remains essentially unchanged by exposure to the thermal pulse. A weak correlation between change in elastic modulus and exposure time was identified. A similarly weak correlation between exposure time and each of load on sample, harmonic stiffness, and hardness was also identified. It was concluded that these correlation were too weak to be used for post-detonation forensics
Isoscalar meson spectroscopy from lattice QCD
We extract to high statistical precision an excited spectrum of
single-particle isoscalar mesons using lattice QCD, including states of high
spin and, for the first time, light exotic JPC isoscalars. The use of a novel
quark field construction has enabled us to overcome the long-standing challenge
of efficiently including quark-annihilation contributions. Hidden-flavor mixing
angles are extracted and while most states are found to be close to ideally
flavor mixed, there are examples of large mixing in the pseudoscalar and axial
sectors in line with experiment. The exotic JPC isoscalar states appear at a
mass scale comparable to the exotic isovector states.Comment: 4 pages, 4 figure
Antimicrobial activity of an iron triple helicate
The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. Here we investigated the potential of the synthetic metallomolecules [Fe2L3]4+ and [Cu2(L’)2]2+ as antibacterial agents. Both molecules have been shown to bind DNA; [Fe2L3]4+ binds in the major groove and causes DNA coiling, whilst [Cu2(L’)2]2+ can act as an artificial nuclease. The work described here shows that only [Fe2L3]4+ is bactericidal for Bacillus subtilis and Escherichia coli. We demonstrate that [Fe2L3]4+ binds bacterial DNA in vivo and, strikingly, that it kills B. subtilis cells very rapidly
High Performance Human Resource Practices And Corporate Entrepreneurship: The Mediating Effect Of Middle Managers Knowledge Collecting And Donating Behaviour
This study develops a mediation model in which high-performance human resource
practices affect corporate entrepreneurship through two dimensions of knowledge
sharing: knowledge collecting and knowledge donating. In a sample of 292 middle
managers from Malaysia, we find that high-performance human resource practices relate
positively to corporate entrepreneurship, and this relation is mediated by knowledge
sharing. The results suggest that the willingness of middle managers to engage in
knowledge sharing serves as a partial mediator to attenuate this positive relationship.
However, an interesting outcome from this study is that although high-performance
human resource practices are positively related to the willingness of middle managers to
collect and donate knowledge, only middle managers' willingness to donate knowledge
was found to partially mediate the relationship between high-performance human
resource practices and corporate entrepreneurship. We discuss the theoretical and
managerial implications for human resource management research and practice
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