Design of catalytic monoliths for closed-cycle carbon dioxide lasers

Pulsed carbon dioxide (CO2) lasers have many applications in aeronautics, space research, weather monitoring and other areas. Full exploitation of the potential of these lasers in hampered by the dissociation of CO2 that occurs during laser operation. The development of closed-cycle CO2 lasers requires active CO-O2 recombination (CO oxidation) catalyst and design methods for implementation of catalysts in CO2 laser systems. A monolith catalyst section model and associated design computer program, LASCAT, are presented to assist in the design of a monolith catalyst section of a closed cycle CO2 laser system. Using LASCAT,the designer is able to specify a number of system parameters and determine the monolith section performance. Trade-offs between the catalyst activity, catalyst dimensions, monolith dimensions, pressure drop, O2 conversion, and other variables can be explored and adjusted to meet system design specifications. An introduction describes a typical closed-cycle CO2 system, and indicates some advantages of a closed cycle laser system over an open cycle system and some advantages of monolith support over other types of supports. The development and use of a monolith catalyst model is presented. The results of a design study and a discussion of general design rules are given

A method for the automatic standards for classification of multispectral images obtained from orbit in coastal waters

There are no author-identified significant results in this report

Developing Rehab Strategies For Drinking Water Networks

Summary: Urban drinking water networks come at age and need more and more rehabilitation. These needs are largely determined by the length of pipes which have been laid into the ground during past decades with different materials and technologies. There is empirical evidence from failure and rehabilitation statistics that particular pipe types have specific service lives. Thus service life distributions can be applied in a cohort survival model for a differentiated annual forecast of the mileage of pipes reaching the end of their service life and, therefore, being in need of rehabilitation in a particular year. Within the bands of future rehabilitation needs, medium range programs can be designed defining annual targets for specific pipes to be rehabilitated with new materials and technologies. The cost of such rehab programs must be evaluated with respect to their long term effects. Whereas annual rehab investments are derived from specific unit costs, cost savings and other benefits from rehabilitation, during the program period and beyond, are more difficult to forecast. The rehab program may have insufficient effects with respect to reducing failures and leakage and enhancing network service reliability. Some of these effects can be expressed in monetary terms and evaluated with dynamic investment methods in a cost benefit framework. This paper presents a framework for exploring network rehab strategies and describes the method for forecasting the effects of specific rehab programs. A cohort survival model with specific aging functions is linked to a simulation model which calculates the effects of advanced or postponed rehabilitation on some network performance indicators such as failure and leakage rate and average residual life expectancy of pipes in the network. Based on these results, a multi-criteria evaluation procedure is presented for choosing the best rehab program from a set of alternatives. The case of an East German water utility shows how this general approach has been applied for developing a medium term rehab strategy for a the network of water mains. Keywords. Drinking water network, rehabilitation, service life of pipe types, strategic investment planning 1 INTRODUCTION -NEED FOR LONGER VIEW ON INFRASTRUCTURE REHABILITATION Most water utilities have not developed a long-term rehabilitation strategy, nor do they systematically explore their options for maintaining or upgrading the water distribution network. Usually they decide on a year-to-year base which elements of the water supply system should be rehabilitated. At best, a list of most urgent rehabilitation projects is established and work proceeds along this list of projects that are "in the pipeline" as long as there are funds available and the budget is not cut by other investment needs such as for the supply of new building developments or the repair of unforeseen pipeline damage. This procedure allows flexible response to whatever comes up, and to some degree, of course, water utilities will always use this re-active "fire brigade" approach, not only because of our limited forecasting capabilities. However, there is a large potential for reducing this "muddling through" and for improving the efficiency of water network rehabilitation. Network information systems, which have been installed in all major water utilities by now, provide a rich source of information which should be used in a pro-active approach to network rehabilitation. Research is under way on this subjec

Measuring the equation of state of a hard-disc fluid

We use video microscopy to study a two-dimensional (2D) model fluid of charged colloidal particles suspended in water and compute the pressure from the measured particle configurations. Direct experimental control over the particle density by means of optical tweezers allows the precise measurement of pressure as a function of density. We compare our data with theoretical predictions for the equation of state, the pair-correlation function and the compressibility of a hard-disc fluid and find good agreement, both for the fluid and the solid phase. In particular the location of the transition point agrees well with results from Monte Carlo simulations.Comment: 7 pages, to appear in EPL, slightly corrected versio

Clinical disease course and survival outcomes following disease recurrence in adenoid cystic carcinoma with and without NOTCH signaling pathway activation.

BACKGROUND: Adenoid cystic carcinoma (ACC) is a rare salivary cancer. The highest rates of disease recurrence are in patients with NOTCH pathway activation, reported in up to 20%. Novel drugs targeting NOTCH signaling are under investigation in the recurrent/metastatic (R/M) setting. To understand their clinical utility, there is an urgent need to better characterize the disease course and outcomes following current standard of care treatment. METHODS: 120 patients with R/M ACC underwent clinical review at a single UK Cancer Centre. Patients were retrospectively assessed for tumor NOTCH pathway activation using next generation sequencing (NGS) targeting NOTCH1/2/3 genes and/or NOTCH1 intra-cellular domain (NICD1) immunohistochemistry. Demographic and treatment data were extracted from the clinical notes. Kaplan-Meier survival analysis was performed using log rank test. RESULTS: NOTCH pathway activation was identified in 13/120 patients (11 %). In 12/101 patients analyzed by NGS, NOTCH1/3 activating somatic mutations were identified, and a further patient was identified with NICD1 diffuse nuclear staining in whom NGS testing was not possible. Patients with NOTCH pathway activation had shorter median RFS (1.1 vs 3.4 years, p = 0.2032) and significantly reduced median OS from diagnosis (4.0 vs 16.3 years, p < 0.0001). There was significantly reduced median OS from time of disease recurrence/metastasis (1.9 vs 9.6 years, p < 0.0001). CONCLUSION: This study clearly demonstrates a reduction in OS from time of first confirmed disease recurrence/metastasis for patients with NOTCH pathway activated ACC. This provides support for developing new drugs for this sub-group of patients, for whom clinical outcomes are significantly worse and effective treatments are lacking

Scaling Parameters for Dynamic Diffusion-Reaction over Porous Catalysts

The effect of diffusion resistance in porous solid catalysts on reaction rate during periodic cycling of CO concentration is shown for CO oxidation over Pt/Al2O3 by numerical simulation. At some cycling frequencies, the average reaction rate during cycling is higher than the steady-state rate at the mean CO concentration, as expected for this nonlinear, reactant-inhibited reaction. In order to identify major aspects of dynamic diffusion-reaction behavior, a simple kinetic mechanism that shows the main features of CO oxidation and other reactions with significant inhibition by reactants is investigated. A single dimensionless parameter group, the dynamic diffusion coefficient, is added when going from steady-state to unsteady-state diffusion-reaction equations. In the dynamic diffusion coefficient, the rate at which the gas-phase reactant diffuses is reduced by the surface adsorption capacity of the catalyst. The frequency at which the peak average rate occurs is controlled by the dynamic diffusion coefficient

Gender equality and girls education: Investigating frameworks, disjunctures and meanings of quality education

The article draws on qualitative educational research across a diversity of low-income countries to examine the gendered inequalities in education as complex, multi-faceted and situated rather than a series of barriers to be overcome through linear input–output processes focused on isolated dimensions of quality. It argues that frameworks for thinking about educational quality often result in analyses of gender inequalities that are fragmented and incomplete. However, by considering education quality more broadly as a terrain of quality it investigates questions of educational transitions, teacher supply and community participation, and develops understandings of how education is experienced by learners and teachers in their gendered lives and their teaching practices. By taking an approach based on theories of human development the article identifies dynamics of power underpinning gender inequalities in the literature and played out in diverse contexts and influenced by social, cultural and historical contexts. The review and discussion indicate that attaining gender equitable quality education requires recognition and understanding of the ways in which inequalities intersect and interrelate in order to seek out multi-faceted strategies that address not only different dimensions of girls’ and women’s lives, but understand gendered relationships and structurally entrenched inequalities between women and men, girls and boys

Evolution of avalanche conducting states in electrorheological liquids

Charge transport in electrorheological fluids is studied experimentally under strongly nonequlibrium conditions. By injecting an electrical current into a suspension of conducting nanoparticles we are able to initiate a process of self-organization which leads, in certain cases, to formation of a stable pattern which consists of continuous conducting chains of particles. The evolution of the dissipative state in such system is a complex process. It starts as an avalanche process characterized by nucleation, growth, and thermal destruction of such dissipative elements as continuous conducting chains of particles as well as electroconvective vortices. A power-law distribution of avalanche sizes and durations, observed at this stage of the evolution, indicates that the system is in a self-organized critical state. A sharp transition into an avalanche-free state with a stable pattern of conducting chains is observed when the power dissipated in the fluid reaches its maximum. We propose a simple evolution model which obeys the maximum power condition and also shows a power-law distribution of the avalanche sizes.Comment: 15 pages, 6 figure

A templating approach to controlling the growth of coevaporated halide perovskites

Metal halide perovskite semiconductors have shown significant potential for use in photovoltaic (PV) devices. While fabrication of perovskite thin films can be achieved through a variety of techniques, thermal vapor deposition is particularly promising, allowing for high-throughput fabrication. However, the ability to control the nucleation and growth of these materials, particularly at the charge-transport layer/perovskite interface, is critical to unlocking the full potential of vapor-deposited perovskite PV. In this study, we explore the use of a templating layer to control the growth of coevaporated perovskite films and find that such templating leads to highly oriented films with identical morphology, crystal structure, and optoelectronic properties independent of the underlying layers. Solar cells incorporating templated FA0.9Cs0.1PbI3–xClx show marked improvements with steady-state power conversion efficiency over 19.8%. Our findings provide a straightforward and reproducible method of controlling the charge-transport layer/coevaporated perovskite interface, further clearing the path toward large-scale fabrication of efficient PV devices