Inspection report Wyggeston and Queen Elizabeth I College

Date(s) of inspection: 2–6 December 200

The Status and Future of Flywheel Energy Storage

Flywheels, one of the earliest forms of energy storage, could play a significant role in the transformation of the electrical power system into one which is fully sustainable yet low cost. This article describes the major components that make up a flywheel configured for electrical storage and why current commercially available designs of steel and composite rotor families coexist. In the process, design drivers, based on fundamentals are explained in a clear and simple manner inclusive of approaches to safety. The robust characteristics of flywheels deem them highly suitable for applications requiring fast response and high daily cycles, a need that is growing as grid inertia reduces. Lithium Ion batteries are currently the technology of choice for fast response but suffer from limited cycle and calendar life. This can be mitigated by having sufficient energy capacity to limit depth of discharge during short duration cycles whilst using this capacity to earn revenue for provision of other services. Now, as other mechanical, thermal to electric and renewable fuel based storage technologies develop, these will provide storage at a lower cost, greater duration and in a more sustainable way than Lithium Ion. However, the need for fast response storage will remain and steel flywheels are well placed to provide this given potential for low power cost and their sustainability credentials. In order to obtain cost estimates for flywheels in volume production, the cost of the power and storage elements were separated out with costs for each based on similar technologies in volume production. These indicate significantly lower costs than given for current commercially available flywheels, none of which are in volume production relative to Lithium Ion. Finally, some areas of research with potential to improve performance are described but, to be worthwhile, these developments must not lead to increased costs

Finite random coverings of one-complexes and the Euler characteristic

This article presents an algebraic topology perspective on the problem of finding a complete coverage probability of a one dimensional domain $X$ by a random covering, and develops techniques applicable to the problem beyond the one dimensional case. In particular we obtain a general formula for the chance that a collection of finitely many compact connected random sets placed on $X$ has a union equal to $X$. The result is derived under certain topological assumptions on the shape of the covering sets (the covering ought to be {\em good}, which holds if the diameter of the covering elements does not exceed a certain size), but no a priori requirements on their distribution. An upper bound for the coverage probability is also obtained as a consequence of the concentration inequality. The techniques rely on a formulation of the coverage criteria in terms of the Euler characteristic of the nerve complex associated to the random covering.Comment: 25 pages,2 figures; final published versio

Students Learned Lessons Well

Editor’s note: It’s clear that one of the many lessons Charlotte Filer ’54 taught her students was accuracy, accuracy, accuracy. And a number of them caught an error in the last issue of Linfield Magazine. Marvin Henberg wrote that “journalism became a separate major in 1970.” Many readers with journalism degrees prior to that time wrote to protest this date, the result of a typographical error which we regret. The actual date for the journalism major was 1950. As is the case with many Linfield professors, Filer gave her students much more than just class time. She became an integral part of their lives and careers and many remain in touch with her to this day

The Index Effect: An Investigation of the Price, Volume and Trading Effects Surrounding Changes to the S & P Australian Indices

This paper examines the stock price and volume effects surrounding the announcement of constituent changes to the S&P/ASX 200 and four supplementary indices. Between April 2000 and December 2002 additions to (deletions from) the ASX 200 were associated with a significant price rise (fall) over the 10 day period following the market announcement of the change. Additions (deletions) also displayed a significant rise (fall) on the announcement date itself. These findings were corroborated by significant increases in trading volume over the same intervals, suggesting heavy trading activity by index funds in response to changes to the ASX 200. Following the implementation of these changes, both additions and deletions experienced a significant price reversion, supporting the price pressure hypothesis. In contrast, none of the supplementary indices displayed evidence of stock price or volume effects, thereby precluding the information and liquidity hypotheses as viable explanations for the findings of this research.Index change; price effect; volume effect; index fund; price pressure.