A network approach to parts provisioning for apollo prelaunch operations

Network approach to replacement-parts policy for Apollo prelaunch operation

Double marking revisited

In 2002, the Qualifications and Curriculum Authority (QCA) published the report of an independent panel of experts into maintaining standards at Advanced Level (A-Level). One of its recommendations was for: ‘limited experimental double marking of scripts in subjects such as English to determine whether the strategy would signi-ficantly reduce errors of measurement’ (p. 24). This recommendation provided the impetus for this paper which reviews the all but forgotten literature on double marking and considers its relevance now

The use of remote sensing in solving Florida's geological and coastal engineering problems

LANDSAT imagery and NASA high altitude color infrared (CIR) photography were used to select suitable sites for sanitary landfill in Volusia County, Florida and to develop techniques for preventing sand deposits in the Clearwater inlet. Activities described include the acquisition of imagery, its analysis by the IMAGE 100 system, conventional photointerpretation, evaluation of existing data sources (vegetation, soil, and ground water maps), site investigations for ground truth, and preparation of displays for reports

Short sea shipping: Lessons for or from Australia?

Over the past decade, there has been a substantial volume of research on short sea shipping and related national maritime transport regulation. In spite of significant support for the policy of growing the volume of short sea shipping in Europe, and the signing of a Memorandum of Cooperation within NAFTA in 2003, there has not been the level of adoption by cargo interests or shipping lines expected. In Australia, where the regulatory environment is somewhat different from Europe or North America, the industry is more focused on the bulk sector and the Rudd Government is contemplating an agenda of maritime reform. This situation presents an opportunity to build an understanding of why, how and whether short sea shipping works, and, in particular, what lessons from the Australian experience might apply to the Canadian and/or North American context and vice versa. This paper builds on two separate but linked streams of research. On one hand, it will review the research conducted in North America. Large-scale studies have been undertaken for Transport Canada over the past five years, and several studies have also been conducted in the U.S. On the other, it reviews the studies undertaken in Australia, where short sea shipping received considerable attention from both consultants and academics, and there has been a recent government investigation into the coastal shipping industry. In its examination of research done to date, this paper explores the lessons from these studies by answering four research questions. It draws preliminary conclusions about the role of the regulatory environment in promoting or deterring the development of land transport– competitive short sea services and about which research agenda gaps remain to be filled. The paper does not focus on bulk shipping; the key emphasis is on what governments need to consider if they seek to induce switching from land modes, like truck or rail, to coastal shipping in order to revitalise the domestic industry or improve GHG-efficiency in the transport sector or both

Demixing kinetics of phase separated polymer solutions in microgravity

Phase separated solutions of two neutral polymers in buffer provide a useful and versatile medium for the partition separation of biological cells. However, the efficiency of such separations is orders of magnitude lower than the thermodynamic limit. To test the hypothesis that this inefficiency is at least partially due to the convection and sedimentation that occur during the gravity driven demixing that follows introduction of cells to the systems, a series of experiments were begun aimed at performing cell partition in a low g environment. Demixing of isopycnic three polymer solvent systems was studied, experiments were performed on KC-135 aircraft and one shuttle middeck experiment was completed. Analysis of the results of these experiments and comparisons with the predictions of scaling relations for the dependence of phase domain size on time, derived for a number of possible demixing mechanisms, are presented

Induced topological pressure for countable state Markov shifts

We introduce the notion of induced topological pressure for countable state Markov shifts with respect to a non-negative scaling function and an arbitrary subset of finite words. Firstly, the scaling function allows a direct access to important thermodynamical quantities, which are usually given only implicitly by certain identities involving the classically defined pressure. In this context we generalise Savchenko's definition of entropy for special flows to a corresponding notion of topological pressure and show that this new notion coincides with the induced pressure for a large class of H\"older continuous height functions not necessarily bounded away from zero. Secondly, the dependence on the subset of words gives rise to interesting new results connecting the Gurevi{\vc} and the classical pressure with exhausting principles for a large class of Markov shifts. In this context we consider dynamical group extentions to demonstrate that our new approach provides a useful tool to characterise amenability of the underlying group structure.Comment: 28 page

Assessing filtering of mountaintop CO2 mole fractions for application to inverse models of biosphere-atmosphere carbon exchange

pre-printThere is a widely recognized need to improve our understanding of biosphere-atmosphere carbon exchanges in areas of complex terrain including the United States Mountain West. CO2 fluxes over mountainous terrain are often difficult to measure due to unusual and complicated influences associated with atmospheric transport. Consequently, deriving regional fluxes in mountain regions with carbon cycle inversion of atmospheric CO2 mole fraction is sensitive to filtering of observations to those that can be represented at the transport model resolution. Using five years of CO2 mole fraction observations from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON), five statistical filters are used to investigate a range of approaches for identifying regionally representative CO2 mole fractions. Test results from three filters indicate that subsets based on short-term variance and local CO2 gradients across tower inlet heights retain nine-tenths of the total observations and are able to define representative diel variability and seasonal cycles even for difficult-to-model sites where the influence of local fluxes is much larger than regional mole fraction variations. Test results from two other filters that consider measurements from previous and following days using spline fitting or sliding windows are overly selective. Case study examples showed that these windowing-filters rejected measurements representing synoptic changes in CO2, which suggests that they are not well suited to filtering continental CO2 measurements. We present a novel CO2 lapse rate filter that uses CO2 differences between levels in the model atmosphere to select subsets of site measurements that are representative on model scales. Our new filtering techniques provide guidance for novel approaches to assimilating mountain-top CO2 mole fractions in carbon cycle inverse models