12,974 research outputs found
Study of hot wire techniques in low density flows with high turbulence levels
Prediction of heat, mass, species, and momentum fluxes in a space vehicle and aerodynamic noise production by supersonic jet and rocket exhausts requires a predictability of the associated turbulence fields. The hot wire is a technique that will allow an experimental determination of turbulent properties
S-Track Stabilization of Heterotic de Sitter Vacua
We present a new mechanism, the S-Track, to stabilize the volume modulus S in
heterotic M-theory flux compactifications along with the orbifold-size T
besides complex structure and vector bundle moduli stabilization. The key
dynamical ingredient which makes the volume modulus stabilization possible, is
M5-instantons arising from M5-branes wrapping the whole Calabi-Yau slice. These
are natural in heterotic M-theory where the warping shrinks the Calabi-Yau
volume along S^1/Z_2. Combined with H-flux, open M2-instantons and hidden
sector gaugino condensation it leads to a superpotential W which stabilizes S
similar like a racetrack but without the need for multi gaugino condensation.
Moreover, W contains two competing non-perturbative effects which stabilize T.
We analyze the potential and superpotentials to show that it leads to heterotic
de Sitter vacua with broken supersymmetry through non-vanishing F-terms.Comment: 16 pages, 2 figures; final PRD versio
A Small Cosmological Constant and Backreaction of Non-Finetuned Parameters
We include the backreaction on the warped geometry induced by non-finetuned
parameters in a two domain-wall set-up to obtain an exponentially small
Cosmological Constant . The mechanism to suppress the Cosmological
Constant involves one classical fine-tuning as compared to an infinity of
finetunings at the quantum level in standard D=4 field theory.Comment: 13 pages, minor corrections and references adde
A new approach to the pulsed thermocouple for high gas temperature measurements
Pulsed thermocouple systems can be used to measure gas temperatures above the melting point of the thermocouple by various techniques of short term of intermittent exposure of the thermocouple operating at lower temperatures. An approach is described which uses a thermocouple cooled by a small jet of inert gas. When a measurement is to be made, the cooling jet is turned off and the thermocouple allowed to heat up to near its melting point, at which time the cooling is reapplied. The final temperature which the thermocouple should have attained is then calculated by extrapolating an exponential curve fit to the data. Temperature measurements can be recorded and displayed in near real time by using modern high-speed computing systems to perform these calculations. Examples of the technique applied to high temperature jet engine combustor development are presented
Coarse Graining Makes It Hard to See Micro-Macro Entanglement
Observing quantum effects such as superpositions and entanglement in
macroscopic systems requires not only a system that is well protected against
environmental decoherence, but also sufficient measurement precision. Motivated
by recent experiments, we study the effects of coarse-graining in photon number
measurements on the observability of micro-macro entanglement that is created
by greatly amplifying one photon from an entangled pair. We compare the results
obtained for a unitary quantum cloner, which generates micro-macro
entanglement, and for a measure-and-prepare cloner, which produces a separable
micro-macro state. We show that the distance between the probability
distributions of results for the two cloners approaches zero for a fixed
moderate amount of coarse-graining. Proving the presence of micro-macro
entanglement therefore becomes progressively harder as the system size
increases.Comment: 5 pages, 3 figure
Aspects of Nucleon Chiral Perturbation Theory
I review recent progress made in the calculation of nucleon properties in the
framework of heavy baryon CHPT. Topics include: Compton scattering,
scattering, the anatomy of a low-energy constant and the induced pseudoscalar
form factor.Comment: plain TeX (macro included), 12pp, lecture delivered at the workshop
on "Chiral Dynamics: Theory and Experiments", MIT, July 25-29, 199
Parenting style as a predictor of music preference
Although previous research has established relationships between perceived parenting styles and children’s deviant behaviours and links between these behaviours and a liking for intense and rebellious music, no research has explored the associations between perceived parenting styles and children’s liking for different music styles. Whereas previous research has considered musical taste by looking at a small number of individual difference variables in isolation from one another, the present research used a cross-sectional correlational design to investigate whether parenting styles, the Big Five personality traits, sensation seeking, age, and gender were associated with a liking for different music styles. In total, 336 Australians completed an online, self-report questionnaire. Analyses demonstrated there were relationships between five of the six parenting style variables and five of the music styles considered. This indicates that various parenting styles were associated with musical taste, and the nature of these associations extends well beyond those concerning rebellious music and neglectful parenting that have been identified by previous research
Linkages Between the Phenologies of Jack Pine \u3ci\u3e(Pinus Banksiana)\u3c/i\u3e Foliage and Jack Pine Budworm (Lepidoptera: Tortricidae)
A field study conducted in 2001 and 2002 in the Michigan Upper Peninsula investigated seasonal associations between the development of jack pine, Pinus banksiana Lamb., and larvae of the jack pine budworm Choristoneura pinus Freeman (Lepidoptera: Tortricidae). There was almost no active relationship between post-diapause emerging second instars and elongation of vegetative shoots. Early instars were not closely synchronized with the flushing of current-year needle fascicles, which is required to optimize larval feeding. How- ever, there were close feeding and shelter relationships between early instars and year-2 pollen cone development. Associations with, and larval damage to, year-2 seed cones were dependent upon larval population size and posed only minimal and periodic threats to jack pine seed production. As a consequence, early instar jack pine budworm relied almost exclusively on pollen cones for survival. Third to fifth instars vacated pollen cones as soon as they became desiccated. Only then did these larvae start close associations with vegetative shoots. First, they excised partially emerged needles at their base, and when the needle-pairs completely escaped their fascicle sheath, the larvae fed routinely on the complete needle lamina. Late instars, pupae and adults were associated with previous years’ and current-year foliage without any apparent bias. This study has shown that it might be more practical to time insecticide strategies, which are intended to manage jack pine budworm larvae, to the tree’s phenology rather than jack pine budworm larval indices
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