Design of an advanced 500-hp helicopter transmission

High contact ratio spar gears planetary, spiral besel gears, bearings, investment-cast planet carrier, and investment cast stainless-steel housings are discussed

Indicator systems - resource use in organic systems

A balanced use of resources within organic farming systems is required to maintain sustainable systems. Hence, it is essential to have tools that can assess the use of resources within the farming system and their impact on the environment. The range of tools that have been developed include those assessing local farm-scale issues together with those that assess impacts at the global scale. At the global scale assessments are usually made on the basis of a unit of product whereas at the local scale assessments can also be made on an area basis. In addition, the tools also assess a variety of issues, e.g. biodiversity, pollution potential, energy and water use. The level of detail required for the different assessment tools differs substantially; nevertheless it is essential that the indicator systems developed are based on sound knowledge, are acceptable to the farmers and can guide their future actions

Instrumentation for potentiostatic corrosion studies with distilled water

Corrosion is studied potentiostatically in the corroding environment of distilled water with an instrument that measures the potential of the corroding specimen immediately after interruption of the polarizing current. No current is flowing. The process permits compensation for IR drops when potentiostatic control is used in high resistance systems

Reconstruction of cosmological density and velocity fields in the Lagrangian Zel'dovich Approximation

We present a method for reconstructing cosmological densityn for and velocity fields using the Lagrangian Zel'dovich formalism. . The method involves finding the least action solution for straight line particle paths in an evolving density field. Our starting point is the final, evolved density , so that we are in effect carrying out the standard Zel'dovich Approximation based process in reverse. Using a simple numerical algorithm we are able to minimise the action for the trajectories of several million particles. We apply our method to the evolved density taken from N-body simulations of different cold dark matter dominated universes, testing both the prediction for the present day velocity field and for the initial density field. The method is easy to apply, reproduces the accuracy of the forward Zel'dovich Approximation, and also works directly in redshift space with minimal modification.Comment: 13 pages with only 2 (out 9) figures. MNRAS in press. New Appendix shows the relation between shell crossing and PIZA. A completed version with all 9 figures available by anonymous ftp at ftp://bessel.mps.ohio-state.edu/pub/racc/piza.ps.gz (USA) or ftp://ftp-astro.physics.ox.ac.uk/pub/eg/piza3.ps.gz (UK

Observations of Anomalous Cosmic Rays at 1 AU

Anomalous cosmic rays (ACRs) provide a sensitive probe of the access of energetic particles to the inner heliosphere, varying in intensity by more than two orders of magnitude during the course of the solar cycle. New data which are becoming available from the Advanced Composition Explorer (ACE) can provide a detailed record of ACR intensity and spectral changes on short (~ 1 day) time scales during the approach to solar maximum, which will help address issues of ACR modulation and transport. The elemental and isotopic composition of ACRs provides important information on the source or sources of these particles, while their ionic charge state composition and its energy dependence serves as a diagnostic of their acceleration time scale. We review measurements of the ACR elemental, isotopic, and charge state composition and spectra as determined at 1 AU by SAMPEX, ACE, Wind, and other spacecraft. These results are important input to models of the acceleration, modulation, and transport of ACRs

Elemental and isotopic fractionation in 3He-rich solar energetic particle events

Using data from the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE) mission, heavy ion composition measurements have been made in 26^3He-rich solar energetic particle (SEP) events that occurred between 1998 and 2004. Relative abundances of 13 elements from C through Ni have been investigated, as have the isotopic compositions of the elements Ne and Mg. We find a general tendency for the abundances to follow trends similar to those found in gradual SEP events, in which fractionation can be represented in the form of a power-law in Q/M. However several deviations from this pattern are noted that may provide useful diagnostics of the acceleration process occurring in solar flares

The Solar Energetic Particle Event of 6 May 1998

The abundances of elements from helium to iron have been measured in more than a dozen moderate to large solar energetic particle (SEP) events using the Solar Isotope Spectrometer (SIS) on-board the Advanced Composition Explorer (ACE). Time variations within some of these events and from event to event have been reported previously. This paper presents an analysis of the event of 6 May 1998, for which relatively time-independent abundance ratios are found. This event has been considered to be an example of an impulsive event, a gradual event, and as a hybrid of the two. Difficulties with classifying this event are discussed

Solar Coronal Abundances of Rare Elements Based on Solar Energetic Particles

Although solar energetic particle (SEP) abundances vary from event to event, it has been shown that by accounting for these variations it is possible to use SEP data to obtain reliable estimates of elemental abundances for the solar corona. We analyze ~20 to 65 MeV/nucleon measurements from the Solar Isotope Spectrometer on ACE in large SEP events observed from November 1997 to January 2001 to obtain new values of the average SEP composition of rare species, P, Cl, K, Ti, Mn, Cr, Co, Cu, and Zn, which have had limited statistical accuracy in SEPs in the past. The measured SEP abundances are compared with other sources of solar-system composition data