High temperature spark plug Patent

High temperature spark plug for igniting liquid rocket propellant

The extended hypergeometric class of L\'evy processes

With a view to computing fluctuation identities related to stable processes, we review and extend the class of hypergeometric L\'evy processes explored in Kuznetsov and Pardo (arXiv:1012.0817). We give the Wiener-Hopf factorisation of a process in the extended class, and characterise its exponential functional. Finally, we give three concrete examples arising from transformations of stable processes.Comment: 22 page

The Effects of Blowing Over Various Trailing-edge Flaps on an NACA 0006 Airfoil Section, Comparisons with Various Types of Flaps on other Airfoil Sections, and an Analysis of Flow and Power Relationships for Blowing Systems

The results are presented of a two-dimensional investigation conducted to determine the effect of blowing over various types of trailing-edge flaps on a wing having the NACA 0006 airfoil section and a drooped-nose flap. The position and profile of the trailing-edge flap, the nozzle height, and the location of the flap with respect to the nozzle were found to be important variables. Data from many investigations were used to make an evaluation of the effects of blowing on lift. An analysis was made of flow and power relationships for blowing systems

STOL Simulation Requirements for Development of Integrated Flight/propulsion Control Systems

The role and use of simulation as a design tool in developing integrated systems where design criteria is largely unavailable is well known. This paper addresses additional simulation needs for the development of Integrated Flight/Propulsion Control Systems (IFPCS) which will improve the probability of properly interpreting simulation results. These needs are based on recent experience with power approach flying qualities evaluations of an advanced fighter configuration which incorporated Short Takeoff and Landing (STOL) technologies and earlier experiences with power approach flying qualities evaluations on the AFTI/F-16 program. The use of motion base platforms with axial and normal degrees of freedom will help in evaluating pilot coupling and workload in the presence of high frequency low amplitude axial accelerations produced by high bandwidth airspeed controllers in a gusty environment

The shape of primordial non-Gaussianity and the CMB bispectrum

We present a set of formalisms for comparing, evolving and constraining primordial non-Gaussian models through the CMB bispectrum. We describe improved methods for efficient computation of the full CMB bispectrum for any general (non-separable) primordial bispectrum, incorporating a flat sky approximation and a new cubic interpolation. We review all the primordial non-Gaussian models in the present literature and calculate the CMB bispectrum up to l <2000 for each different model. This allows us to determine the observational independence of these models by calculating the cross-correlation of their CMB bispectra. We are able to identify several distinct classes of primordial shapes - including equilateral, local, warm, flat and feature (non-scale invariant) - which should be distinguishable given a significant detection of CMB non-Gaussianity. We demonstrate that a simple shape correlator provides a fast and reliable method for determining whether or not CMB shapes are well correlated. We use an eigenmode decomposition of the primordial shape to characterise and understand model independence. Finally, we advocate a standardised normalisation method for $f_{NL}$ based on the shape autocorrelator, so that observational limits and errors can be consistently compared for different models.Comment: 32 pages, 20 figure

A framework for assessing crop production from rotations

This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Organic farming systems rely on the management of biological cycles for the provision of nutrients, which are crucial to maximising the production from the system. Rotations based on the use of grass-legume leys are central to the concept of organic farming systems, because they have the potential to support both animal production, and a subsequent, exploitative, arable cropping phase. A major challenge in organic farming is managing the supply of nitrogen, since it has a key role in governing both productivity and environmental impact. Hence, within a rotational system, there is a need to understand the complex interactions that are occurring between crop species and management, livestock production system and the impact of soil and climate on these processes. To understand these interactions, a framework is being developed for rotational farming systems that describes the soil nitrogen, crop growth and livestock production. The framework must address questions that are relevant to researchers and extensions workers. Typical questions relate to the management of nutrients in the short and long-term. Additionally, there are concerns over the impact of weeds, pests and diseases on productivity, as well as the impact of adopting new strategies or crops on the farming system

Proctolin and an Endogenous Proctolin-Like Peptide Enhance the Contractility of the Limulus Heart

Synthetic proctolin increases the force but not the rate of heart contractions of Limulus in a time- and dose-dependent manner. The threshold of this effect is 3 × 10−10M and the ED50 is approximately 10−8M. At concentrations up to 10−7 M, proctolin has no effect on the rhythmic electrical activity of the isolated cardiac ganglion, and it does not change the simple and compound postsynaptic potentials recorded at the cardiac neuromuscular junction. Proctolin acts directly on the cardiac muscle fibres. Electrically stimulated myocardia show a proctolin-induced increase in contraction amplitude with the same concentration dependence as the intact heart. A compound with an apparent molecular weight of 700–800 occurs in the Limulus nervous system, particularly in the cardiac ganglion. This compound resembles proctolin in being heat-stable, resistant to trypsin and chymotrypsin cleavage, and losing activity in a time-dependent manner in response to treatment with leucine aminopeptidase or pronase. This peptide induces spontaneous contractions and a contracture of the cockroach hindgut in a manner similar to proctolin. Moreover, the Limulus inotropic peptide, like proctolin, increases the force of contraction of the Limulus heart without affecting beat frequency. It is concluded that an endogenous, proctolin-like peptide is an inotropic modulator of the Limulus heart, acting directly on the muscle fibres and not affecting cardiac ganglion activity

Primordial non-Gaussianity and the CMB bispectrum

We present a new formalism, together with efficient numerical methods, to directly calculate the CMB bispectrum today from a given primordial bispectrum using the full linear radiation transfer functions. Unlike previous analyses which have assumed simple separable ansatze for the bispectrum, this work applies to a primordial bispectrum of almost arbitrary functional form, for which there may have been both horizon-crossing and superhorizon contributions. We employ adaptive methods on a hierarchical triangular grid and we establish their accuracy by direct comparison with an exact analytic solution, valid on large angular scales. We demonstrate that we can calculate the full CMB bispectrum to greater than 1% precision out to multipoles l<1800 on reasonable computational timescales. We plot the bispectrum for both the superhorizon ('local') and horizon-crossing ('equilateral') asymptotic limits, illustrating its oscillatory nature which is analogous to the CMB power spectrum

Thermomagnetic analysis of meteorites. 3: C3 and C4 chondrites

Thermomagnetic analysis on all of the C3 and C4 chondrites, conducted under conditions of controlled oxygen fugacity, indicates the presence of a thermally unstable component in at least 5 of the C3 chondrites which upon heating results in magnetite production. This unstable component is most likely troilite (FeS). The presence of the unstable substance may affect the estimation of paleointensities in meteorites which contain it. Our results indicate that Grosnaja, Ornans, Kainsaz, Felix, and Warrenton are likely to be less complicated for paleointensity determinations than the other C3 chondrites. Both C4 chondrites should lead to reliable results