Generalized keesom potential

Field theoretic approach for generalization of expressions for adiabatic interaction between two rotating dipolar system

Development of phase-change coatings for use as variable thermal control surfaces Final report

Phase change coatings for use as variable thermal control surface

Uniqueness of Current Cosmic Acceleration

One of the strongest arguments against the cosmological constant as an explanation of the current epoch of accelerated cosmic expansion is the existence of an earlier, dynamical acceleration, i.e. inflation. We examine the likelihood that acceleration is an occasional phenomenon, putting stringent limits on the length of any accelerating epoch between recombination and the recent acceleration; such an epoch must last less than 0.05 e-fold (at z>2) or the matter power spectrum is modified by more than 20%.Comment: 6 pages, 5 figures; v2 corrected typo in Eq.

Single stage experimental evaluation of slotted rotor and stator blading. Part I - Analysis and design

Analysis and design of slotted rotor and stator blading for application to compressors in advanced airbreathing propulsion system

Systematic Errors in Future Weak Lensing Surveys: Requirements and Prospects for Self-Calibration

We study the impact of systematic errors on planned weak lensing surveys and compute the requirements on their contributions so that they are not a dominant source of the cosmological parameter error budget. The generic types of error we consider are multiplicative and additive errors in measurements of shear, as well as photometric redshift errors. In general, more powerful surveys have stronger systematic requirements. For example, for a SNAP-type survey the multiplicative error in shear needs to be smaller than 1%(fsky/0.025)^{-1/2} of the mean shear in any given redshift bin, while the centroids of photometric redshift bins need to be known to better than 0.003(fsky/0.025)^{-1/2}. With about a factor of two degradation in cosmological parameter errors, future surveys can enter a self-calibration regime, where the mean systematic biases are self-consistently determined from the survey and only higher-order moments of the systematics contribute. Interestingly, once the power spectrum measurements are combined with the bispectrum, the self-calibration regime in the variation of the equation of state of dark energy w_a is attained with only a 20-30% error degradation.Comment: 20 pages, 9 figures, to be submitted to MNRAS. Comments are welcom

Development of phase-change coatings for use as variable thermal control surfaces Final report, 8 Mar. 1967 - 8 Mar. 1968

Development of phase-change coatings for thermal control of spacecraft surface

Parametric resonance for antineutrino conversions using LSND best-fit results with a 3+1 flavor scheme

An analytical solution to a parametric resonance effect for antineutrinos in a 3+1 flavor (active+sterile) scheme using multiple non-adiabatic density shifts is presented. We derive the conditions for a full flavor conversion for antineutrino oscillations $\bar{\nu}_\alpha \to \bar{\nu}_s$ $(\alpha=e,\mu,\tau)$ under the assumption that LSND best-fits for the mixing parameters are valid in a short-baseline accelerator experiment. We show that the parametric resonance effect can be exploited to increase the effective antineutrino oscillation length by a factor of 10-40, thus sustaining a high oscillation probability for a much longer period of time than in the vacuum scenario. We propose a realistic experimental setup that could probe for this effect which leaves a signature in terms of a specific oscillation probability profile. Moreover, since the parametric resonance effect is valid in any 2 or 1+1 flavor approximation, our results could be suggestive for future short-baseline accelerator neutrino detection experiments.Comment: 6 pages, 4 figure

Evaluation of trends in derived snowfall and rainfall across Eurasia and linkages with discharge to the Arctic Ocean

To more fully understand the role of precipitation in observed increases in freshwater discharge to the Arctic Ocean, data from a new archive of bias-adjusted precipitation records for the former USSR (TD9813), along with the CRU and Willmott-Matsuura data sets, were examined for the period 1936–1999. Across the six largest Eurasian river basins, snowfall derived from TD9813 exhibits a strongly significant increase until the late 1950s and a moderately significant decrease thereafter. A strongly significant decline in derived rainfall is also noted. Spatially, snowfall increases are found primarily across north-central Eurasia, an area where the rainfall decreases are most prominent. Although no significant change is determined in Eurasian-basin snowfall over the entire 64 year period, we note that interpolation from early, uneven station networks causes an overestimation of spatial precipitation, and that the local snowfall trends determined from gridded TD9813 data are likely underestimated. Yet, numerous uncertainties in historical Arctic climate data and the sparse, irregular nature of Arctic station networks preclude a confident assessment of precipitation-discharge linkages during the period of reported discharge trends

A forgotten facial nerve tumour: granular cell tumour of the parotid and its implications for treatment

We present a rare case of a facial nerve granular cell tumour in the right parotid gland, in a 10-year-old boy. A parotid or neurogenic tumour was suspected, based on magnetic resonance imaging. Intra-operatively, strong adhesions to surrounding structures were found, and a midfacial nerve branch had to be sacrificed for complete tumour removal. Recent reports verify that granular cell tumours arise from Schwann cells of peripheral nerve branches. The rarity of this tumour within the parotid gland, its origin from peripheral nerves, its sometimes misleading imaging characteristics, and its rare presentation with facial weakness and pain all have considerable implications on the surgical strategy and pre-operative counselling. Fine needle aspiration cytology may confirm the neurogenic origin of this lesion. When resecting the tumour, the surgeon must anticipate strong adherence to the facial nerve and be prepared to graft, or sacrifice, certain branches of this nerv