Lightweight piston

A lightweight piston composed of carbon-carbon composites is presented. The use of carbon-carbon composites over conventional materials, such as aluminum, reduces piston weight and improves thermal efficiency of the internal combustion reciprocation engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance is so small as to eliminate the necessity for piston rings. Use of the carbon-carbon composite has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance

Composite piston

A composite piston structure is disclosed which provides a simple and reliable means for joining a carbon-carbon or ceramic piston cap with a metallic piston body. Attachment is achieved by means of a special geometry which compensates for differences in thermal expansion without complicated mechanical fastening devices. The shape employs a flange created by opposed frustoconical shapes with coincident vertices intersecting on the radial centerline of the piston in order to retain the piston cap. The use of carbon-carbon for the piston cap material allows a close fit between the piston and a cylinder wall, eliminating the need for piston rings. The elimination of extra mechanical parts of previous composite pistons provides a lightweight composite piston capable of extended high temperature operation

The latitude - local time dependence of low energy cosmic ray cut-offs in a realistic geomagnetic field

Latitude - local time dependence of low energy cosmic ray cut-offs in realistic geomagnetic fiel

Lusztig Induction, Unipotent Supports, and Character Bounds

Recently, a strong exponential character bound has been established in [3] for all elements $g \in \mathbf{G}^F$ of a finite reductive group $\mathbf{G}^F$ which satisfy the condition that the centraliser $C_{\mathbf{G}}(g)$ is contained in a $(\mathbf{G},F)$-split Levi subgroup $\mathbf{M}$ of $\mathbf{G}$ and that $\mathbf{G}$ is defined over a field of good characteristic. In this paper, assuming a weak version of Lusztig's conjecture relating irreducible characters and characteristic functions of character sheaves holds, we considerably generalize this result by removing the condition that $\mathbf{M}$ is split. This assumption is known to hold whenever $Z(\mathbf{G})$ is connected or when $\mathbf{G}$ is a special linear or symplectic group and $\mathbf{G}$ is defined over a sufficiently large finite field.Comment: 35 pages; v2. minor improvements to abstract and introduction; v3. further improvements to the exposition; v4. significant changes. Main result now works for special linear and symplectic groups. Added results on groups of type A generalising results of Hildebrand; v5. post referee repor

The Adiabatic Motion of Outer Zone Particles in a Model of the Geoelectric and Geomagnetic Fields

Charged particle motion calculations from model of earths magnetospher

Synchronisation Properties of Trees in the Kuramoto Model

We consider the Kuramoto model of coupled oscillators, specifically the case of tree networks, for which we prove a simple closed-form expression for the critical coupling. For several classes of tree, and for both uniform and Gaussian vertex frequency distributions, we provide tight closed form bounds and empirical expressions for the expected value of the critical coupling. We also provide several bounds on the expected value of the critical coupling for all trees. Finally, we show that for a given set of vertex frequencies, there is a rearrangement of oscillator frequencies for which the critical coupling is bounded by the spread of frequencies.Comment: 21 pages, 19 Figure

Nitric oxide photolysis Final report

Attempt to determine if nitrous oxide is product of nitric oxide photolysis using mass spectrometry and gas chromatograph

Radio pulsar timing observations for GRO

Gamma rays probably provide the best diagnostic tool for probing the enigmatic physics of pulsar magnetospheres. At present, however, only two pulsars - the young, nearby ones in the Crab and Vela X supernova remnants - are reliably detected at gamma-ray energies. With adequate radio observations to provide independent timing information, Gamma Ray Observatory should be able to detect a number of additional pulsars, and the results will be of great benefit in testing magnetospheric theories and models. Timing observations for this purpose were started at a number of radio observatories around the world. The general procedures being used are described. A status report on the work is given

Sudden commencement associated discontinuities in the interplanetary magnetic field observed by IMP 3

Discontinuities in interplanetary magnetic field observed by Explorer 28 satellit

Stewardship Plan for Four Conservation Easements Held by the Town of Newfields

In 2005 the Town of Newfields, NH was awarded a grant by the New Hampshire Estuaries Project. The Eligible Activity applied for, under the category of Land Conservation and Natural Resource Protection was “Development of monitoring plans for town-held easements on conservation lands”. The Town identified four properties on which the they hold conservation easements as the focus of the project. Newfields’ goal in applying for the grant were to have each property visited by the contractor and a local volunteer, conduct an interview with the landowner and a conduct a ground monitoring of the property. Following the visits, baseline documentation reports and a stewardship plan for each easement property would be created. As a part of the plan, the Town also hoped to address policy considerations relating to stewardship of easements