A modelling approach to the development of an active management strategy for the Queen Elizabeth II reservoir

This article outlines the outcome of work that set out to provide one of the specified integral contributions to the overarching objectives of the EU- sponsored LIFE98 project described in this volume. Among others, these included a requirement to marry automatic monitoring and dynamic modelling approaches in the interests of securing better management of water quality in lakes and reservoirs. The particular task given to us was to devise the elements of an active management strategy for the Queen Elizabeth II Reservoir. This is one of the larger reservoirs supplying the population of the London area: after purification and disinfection, its water goes directly to the distribution network and to the consumers. The quality of the water in the reservoir is of primary concern, for the greater is the content of biogenic materials, including phytoplankton, then the more prolonged is the purification and the more expensive is the treatment. Whatever good that phytoplankton may do by way of oxygenation and oxidative purification, it is eventually relegated to an impurity that has to be removed from the final product. Indeed, it has been estimated that the cost of removing algae and microorganisms from water represents about one quarter of its price at the tap. In chemically fertile waters, such as those typifying the resources of the Thames Valley, there is thus a powerful and ongoing incentive to be able to minimise plankton growth in storage reservoirs. Indeed, the Thames Water company and its predecessor undertakings, have a long and impressive history of confronting and quantifying the fundamentals of phytoplankton growth in their reservoirs and of developing strategies for operation and design to combat them. The work to be described here follows in this tradition. However, the use of the model PROTECH-D to investigate present phytoplankton growth patterns in the Queen Elizabeth II Reservoir questioned the interpretation of some of the recent observations. On the other hand, it has reinforced the theories underpinning the original design of this and those Thames-Valley storage reservoirs constructed subsequently. The authors recount these experiences as an example of how simulation models can hone the theoretical base and its application to the practical problems of supplying water of good quality at economic cost, before the engineering is initiated.

Multilayer Active Shell Mirrors

This thesis presents a novel active mirror technology based on carbon fiber composites and replication manufacturing processes. Multiple additional layers are implemented into the structure in order to provide the reflective layer, actuation capabilities and electrode routing. The mirror is thin, lightweight, and has large actuation capabilities. These features, along with the associated manufacturing processes, represent a significant change in design compared to traditional optics. Structural redundancy in the form of added material or support structures is replaced by thin, unsupported lightweight substrates with large actuation capabilities.

Several studies motivated by the desire to improve as-manufactured figure quality are performed. Firstly, imperfections in thin CFRP laminates and their effect on post-cure shape errors are studied. Numerical models are developed and compared to experimental measurements on flat laminates. Techniques to mitigate figure errors for thicker laminates are also identified. A method of properly integrating the reflective facesheet onto the front surface of the CFRP substrate is also presented. Finally, the effect of bonding multiple initially flat active plates to the backside of a curved CFRP substrate is studied. Figure deformations along with local surface defects are predicted and characterized experimentally. By understanding the mechanics behind these processes, significant improvements to the overall figure quality have been made.

Studies related to the actuation response of the mirror are also performed. The active properties of two materials are characterized and compared. Optimal active layer thicknesses for thin surface-parallel schemes are determined. Finite element simulations are used to make predictions on shape correction capabilities, demonstrating high correctabiliity and stroke over low-order modes. The effect of actuator saturation is studied and shown to significantly degrade shape correction performance.

The initial figure as well as actuation capabilities of a fully-integrated active mirror prototype are characterized experimentally using a Projected Hartmann test. A description of the test apparatus is presented along with two verification measurements. The apparatus is shown to accurately capture both high-amplitude low spatial-frequency figure errors as well as those at lower amplitudes but higher spatial frequencies. A closed-loop figure correction is performed, reducing figure errors by 94%.

Active reservoir management: a model solution

Steady-state procedures, of their very nature, cannot deal with dynamic situations. Statistical models require extensive calibration, and predictions often have to be made for environmental conditions which are often outside the original calibration conditions. In addition, the calibration requirement makes them difficult to transfer to other lakes. To date, no computer programs have been developed which will successfully predict changes in species of algae. The obvious solution to these limitations is to apply our limnological knowledge to the problem and develop functional models, so reducing the requirement for such rigorous calibration. Reynolds has proposed a model, based on fundamental principles of algal response to environmental events, which has successfully recreated the maximum observed biomass, the timing of events and a fair simulation of the species succession in several lakes. A forerunner of this model was developed jointly with Welsh Water under contract to Messrs. Wallace Evans and Partners, for use in the Cardiff Bay Barrage study. In this paper the authors test a much developed form of this original model against a more complex data-set and, using a simple example, show how it can be applied as an aid in the choice of management strategy for the reduction of problems caused by eutrophication. Some further developments of the model are indicated.

Bayesian Active Learning for Classification and Preference Learning

Information theoretic active learning has been widely studied for probabilistic models. For simple regression an optimal myopic policy is easily tractable. However, for other tasks and with more complex models, such as classification with nonparametric models, the optimal solution is harder to compute. Current approaches make approximations to achieve tractability. We propose an approach that expresses information gain in terms of predictive entropies, and apply this method to the Gaussian Process Classifier (GPC). Our approach makes minimal approximations to the full information theoretic objective. Our experimental performance compares favourably to many popular active learning algorithms, and has equal or lower computational complexity. We compare well to decision theoretic approaches also, which are privy to more information and require much more computational time. Secondly, by developing further a reformulation of binary preference learning to a classification problem, we extend our algorithm to Gaussian Process preference learning.

Numerical investigation of the active role of the actin cytoskeleton in the compression resistance of cells.

Numerous in-vitro studies have established that cells react to their physical environment and to applied mechanical loading. However, the mechanisms underlying such phenomena are poorly understood. Previous modelling of cell compression considered the cell as a passive homogenous material, requiring an artificial increase in the stiffness of spread cells to replicate experimentally measured forces. In this study, we implement a fully 3D active constitutive formulation that predicts the distribution, remodelling, and contractile behaviour of the cytoskeleton. Simulations reveal that polarised and axisymmetric spread cells contain stress fibres which form dominant bundles that are stretched during compression. These dominant fibres exert tension; causing an increase in computed compression forces compared to round cells. In contrast, fewer stress fibres are computed for round cells and a lower resistance to compression is predicted. The effect of different levels of cellular contractility associated with different cell phenotypes is also investigated. Highly contractile cells form more dominant circumferential stress fibres and hence provide greater resistance to compression. Computed predictions correlate strongly with published experimentally observed trends of compression resistance as a function of cellular contractility and offer an insight into the link between cell geometry, stress fibre distribution and contractility, and cell deformability. Importantly, it is possible to capture the behaviour of both round and spread cells using a given, unchanged set of material parameters for each cell type. Finally, it is demonstrated that stress distributions in the cell cytoplasm and nucleus computed using the active formulation differ significantly from those computed using passive material models.

Optimisation of passive and semi-active heavy vehicle suspensions

An investigation into the potential for reducing road damage by optimising the design of heavy vehicle suspensions is described. In the first part of the paper two simple mathematical models are used to study the optimisation of conventional passive suspensions. Simple modifications are made to the steel spring suspension of a tandem axle trailer and it is found experimentally that RMS dynamic tyre forces can be reduced by 15% and theoretical road damage by 5.2%. A mathematical model of an air-sprung articulated vehicle is validated, and its suspension is optimised according to the simple models. This vehicle generates about 9% less damage than the leaf-sprung vehicle in the unmodified state and it is predicted that, for the operating conditions examined, the road damage caused by this vehicle can be reduced by a further 5.4%. Finally, it is shown experimentally that computer-controlled semi-active dampers have the potential to reduce road damage by a further 5-6%, compared to an air suspension with optimum passive damping. © Copyright 1994 Society of Automotive Engineers, Inc.

The user-value of rural electrification: An analysis and adoption of existing models and theories

User-value is a determining factor for product acceptance in product design. Research on rural electrification to date, however, does not draw sufficient attention to the importance of user-value with regard to the overall success of a project. This is evident from the analysis of project reports and applicable indicators from agencies active in the sector. Learning from the design, psychology and sociology literatures, it is important that rural electrification projects incorporate the value perception of the end-user and extend their success beyond the commonly used criteria of financial value, the appropriateness of the technology, capacity building and technology uptake. Creating value for the end-user is particularly important for project acceptance and the sustainability of a scheme once it has been handed over to the local community. In this research paper, existing theories and models of value-theory are transposed and applied to community operated rural electrification schemes and a user-value framework is developed. Furthermore, the importance of value to the end-user is clarified. Current literature on product design reveals that user-value has different properties, many of which are applicable to rural electrification. Five value pillars and their sub-categories important for the users of rural electrification projects are identified, namely: functional; social significance; epistemic; emotional; and cultural values. These pillars provide the main structure for the conceptual framework developed in this research paper. It is proposed that by targeting the values of the end-user, the key factors of user-value applicable to rural electrification projects will be identified and the sustainability of the project will be better ensured. © 2014 The Authors.

Study of remote sensing based parameter uncertainty in Production Efficiency Models

The remote sensing based Production Efficiency Models (PEMs), springs from the concept of "Light Use Efficiency" and has been applied more and more in estimating terrestrial Net Primary Productivity (NPP) regionally and globally. However, global NPP estimates vary greatly among different models in different data sources and handling methods. Because direct observation or measurement of NPP is unavailable at global scale, the precision and reliability of the models cannot be guaranteed. Though, there are ways to improve the accuracy of the models from input parameters. In this study, five remote sensing based PEMs have been compared: CASA, GLO-PEM, TURC, SDBM and VPM. We divided input parameters into three categories, and analyzed the uncertainty of (1) vegetation distribution, (2) fraction of photosynthetically active radiation absorbed by the canopy (fPAR) and (3) light use efficiency (e). Ground measurements of Hulunbeier typical grassland and meteorology measurements were introduced for accuracy evaluation. Results show that a real-time, more accurate vegetation distribution could significantly affect the accuracy of the models, since it's applied directly or indirectly in all models and affects other parameters simultaneously. Higher spatial and spectral resolution remote sensing data may reduce uncertainty of fPAR up to 51.3%, which is essential to improve model accuracy.

大别山岩石圈有效弹性厚度初步研究

As powerful tools to study the lithosphere dynamics, the effective elastic thickness (Te) as well as the envelope of yielding stress of lithosphere have been attracted great attention of geoscientists in the past thirty years. The oceanic lithosphere, contrary to the continental lithosphere, has more fruits for its simple structures and evolution process. In continent, the lithosphere commonly is complex and variable in the rheological, thermal structures, and has a complicated history. Therefore, the application of the effective elastic thickness in continent is still a subject to learn in a long time. Te, with the definition of the thickness of an elastic plate in theory flexured by the equal benging of the real stress in the lithosphere plate (Turcotte, 1982), marks the depth of transition between elastic and fluid behaviors of rocks subjected to stress exceeding 100 MPa over the geological timescales (McNutt, 1990). There are three methods often adapted: admittance or isostatic response function, coherence and forwarding. In principle, the models of Te consist of thermal-rheological, non-linear Maxwell, non-linear work hardening and rheological layered models. There is a tentative knowledge of Te that it is affected by the following factors: crustal thickness, crust-mantle decoupling, plate bending, boundary conditions of plate (end forces and bending moments), stress state, sedimentary layer, faulting effect, variation in the mountain belts' strike, foreland basin, inheritance of tectonic evolution, convection of mantle, seismic depth and lithosphere strength. In this thesis, the author introduces the geological sketch of the Dabie collisional orogenic belt and the Hefei Basin. The Dabie Mts. is famous for the ultra-high pressure metamorphism. The crustal materials subducted down to the depth of at least 100 km and exhumed. So that the front subjects arise such as the deeply subduction of continent, and the post-collisional crust-mantle interaction. In a geological journey at June of 1999, the author found the rarely variolitic basaltic andesite in the Dabie Mts. It occurs in Susong Group, near Zhifenghe Countryside, Susong County, Anhui Province. It is just to the south of the boundary between the high-grade Susong melange and the ultra-high grade South Dabie melange. It has a noticeable knobby or pitted appearance in the surface. The size of the varioles is about 1-4 mm. In hand-specimen and under microscope, there are distinct contacts between the varioles and the matrice. The mineralogy of the varioles is primarily radiate plagioclase, with little pyroxene, hornblende and quartz. The pyroxene, hornblende and quartz are in the interstices between plagioclase. The matrix is consisted of glass, and micro-crystals of chlorite, epidote and zoisite. It is clearly subjected and extensive alteration. The andesite has an uncommon chemical composition. The SiO_2 content is about 56.8%, TiO_2 = 0.9%, MgO = 6.4%, (Fe_2O_3)_(Total) = 6.7% ～ 7.6%, 100 Mg/(Mg+Fe) = 64.1 ～ 66.2. Mg# is significantly high. The andesite has higher abundances of large-lithophile trace elements (e.g. K, Ba, Sr, LREE), e.g. La/Nd = 5.56-6.07, low abundances of high-strength-field elements (HFSE, e.g. Ta, Nb, P, Ti), particularly Ta and Nb strongly depleted. These are consistent with the characteristics of subducted-related magmas (Pearcce, 1982; Sun and McDonaugh, 1989). In the spider diagram of trace elements, from Ce to right hand, the abundances of elements decrease quickly, showing a characteristic of the continental margins (Pearce, 1982). There has a strongly enrichment of light-rare-earth elements, with a significant diffraction of REEs (the mean value of (La/Yb)_N is 32.84). No Eu anomaly, but there are anomaly high (La/Yb)_N = 28.63-36.74, (La/Y)_N = 70.33 - 82.84. The elements Y and Yb depleted greatly, Y < 20 ppm, Y_N = 2.74-2.84, Yb_N = 2.18 - 2.35. From the La-(La/Sm) diagram, the andesite is derived from partial melting. But the epsilone value of Nd is -18.7 ～ -19.2, so that the material source may be the mantle materials affected by the crustal materials. The Nd model age is 1.9 Ga indicating that the basaltic andesite was resulted from the post-collisional crust-mantle interaction between the subducted Yangze carton and the mantle of Sino-Korea carton. To obtain the Te of the lithosphere beneath the Dabie Mts. and the Hefei Basin, the author applies the coherence method in this thesis. The author makes two topography-gravity profiles (profiles 7~(th) and 9~(th)) across the Dabie Mts. and the Hefei Basin, and calculates the auto-coherence, across coherence, power spectrum, across power spectrum of the topography and gravity of the two profiles. From the relationships between the coherence and the wave-number of profiles. From the relationships between the coherence and the wave-number of profiles 7~(th) and 9~(th), it is obtained that the characteristic wavelengths respectively are 157 km and 126 km. Consequently the values of effective elastic thickness are 6.5 km and 4.8 km, respectively. However, the Te values merely are the minimum value of the lithosphere because the coherencemethod in a relative small region will generate a systemic underestimation. Why there is a so low Te value? In order to check the strength of the lithosphere beneath the Dabie Mts., the authore tries to outline the yielding-stress envelope of the lithosphere. It is suggested that the elastic layers in the crust and upper mantle are 18 km and 35 km, respectively. Since there exist a low viscosity layer about 3-5 km thickness, so it is reasonable that the decoupling between the crust and mantle occurred. So the effective thickness of the lithosphere can be estimated from the two elastic layers. Te is about 34 km. This is the maximum strength of the lithosphere. We can make an approximately estimation about the strength of the lithosphere beneath the Dabie Mts.: Te is about 20-30 km. The author believes that the following factors should be responsible for the low Te value: (1) the Dabie Mts. has elevated strongly since K_3-J_1. The north part of the Dabie Mts. elevates faster than the south part today; (2) there occur large active striking faults in this area. And in the east, the huge Tan-Lu striking fault anyway tends to decrease the lithosphere strength; (3) the lithosphere beneath the Dabie Mts. is heter-homogeneous in spatio-temporal; (4) the study area just locates in the adjacent region between the eastern China where the lithosphere thickness is significantly reduced and the normal western China. These factors will decrease the lithosphere strength.

Active Blobs

A new region-based approach to nonrigid motion tracking is described. Shape is defined in terms of a deformable triangular mesh that captures object shape plus a color texture map that captures object appearance. Photometric variations are also modeled. Nonrigid shape registration and motion tracking are achieved by posing the problem as an energy-based, robust minimization procedure. The approach provides robustness to occlusions, wrinkles, shadows, and specular highlights. The formulation is tailored to take advantage of texture mapping hardware available in many workstations, PC's, and game consoles. This enables nonrigid tracking at speeds approaching video rate.

Cellular and in-vitro models to assess antioxidant activities of seaweed extracts and the potential use of the extracts as ingredients

Seaweeds contain a range of antioxidant compounds such as polyphenols, carotenoids, sulphated polysaccharides and vitamins and have the potential to be used as ingredients in neutraceuticals. The antioxidant activity of crude 60% methanol extracts prepared from five Irish seaweeds, Ascophyllum nodosum, Laminaria hyperborea, Pelvetia canaliculata, Fucus vesiculosus and Fucus serratus were examined using in-vitro assays and a cell model system to determine the antioxidant activity of the extracts and their ability to protect against H2O2 and tert-BOOH-induced DNA damage and alterations in cellular antioxidant status in the human adenocarcinoma, Caco-2 cell line. To optimise the extraction of antioxidant compounds from seaweeds, an accelerated solvent extraction (ASE®) was used in combination with food grade solvents. The antioxidant activity of these extracts against H2O2 and tert-BOOH-induced DNA damage and alterations in cellular antioxidant status was also assessed. Extracts that exhibited the highest antioxidant activity, A. nodosum (100% water and 80% ethanol extracts) and F. vesiculosus (60% ethanol extract) were selected as ingredients for incorporation into fluid milk and yogurt at concentrations of 0.25% and 0.5%. The addition of the seaweed extracts to milk and yogurt did not affect the pH or shelf-life properties of the products. Seaweed addition did however significantly influence the colour properties of the milk and yogurt. Yellowness values were significantly higher in yogurts containing F. vesiculosus at both concentrations and A. nodosum (80% ethanol) at the 0.5% concentration. In milk, the F. vesiculosus (60% ethanol) and A. nodosum (80% ethanol) at both the 0.25% and the 0.5% concentrations had higher greenness and yellowness values than the milk containing A. nodosum (100% water). Sensory analysis revealed that appearance and flavour governed the overall acceptability of yogurts with the control yogurt, and yogurts containing A. nodosum (100% water) were the most preferred samples by panellists. However, in the milk trial the perception of a fishy taste was the determining factor in the negative perception of milk. The unsupplemented control and the milk containing A. nodosum (100% water) at a concentration of 0.5% were the most overall accepted milk samples by the sensory panellists. The antioxidant activity of the extracts in milk and yogurt remained stable during storage as determined by the in-vitro assays. Seaweed supplemented milk and yogurt were also subjected to an in-vitro digestion procedure which mimics the human digestive system. The milk and yogurt samples and their digestates were added to Caco-2 cells to investigate their antioxidant potential however neither the undigested or digested samples protected against H2O2-induced DNA damage in Caco-2 cells.

Toward autonomous measurements of photosynthetic electron transport rates: An evaluation of active fluorescence-based measurements of photochemistry

This study presents a methods evaluation and intercalibration of active fluorescence-based measurements of the quantum yield ( inline image) and absorption coefficient ( inline image) of photosystem II (PSII) photochemistry. Measurements of inline image, inline image, and irradiance (E) can be scaled to derive photosynthetic electron transport rates ( inline image), the process that fuels phytoplankton carbon fixation and growth. Bio-optical estimates of inline image and inline image were evaluated using 10 phytoplankton cultures across different pigment groups with varying bio-optical absorption characteristics on six different fast-repetition rate fluorometers that span two different manufacturers and four different models. Culture measurements of inline image and the effective absorption cross section of PSII photochemistry ( inline image, a constituent of inline image) showed a high degree of correspondence across instruments, although some instrument-specific biases are identified. A range of approaches have been used in the literature to estimate inline image and are evaluated here. With the exception of ex situ inline image estimates from paired inline image and PSII reaction center concentration ( inline image) measurements, the accuracy and precision of in situ inline image methodologies are largely determined by the variance of method-specific coefficients. The accuracy and precision of these coefficients are evaluated, compared to literature data, and discussed within a framework of autonomous inline image measurements. This study supports the application of an instrument-specific calibration coefficient ( inline image) that scales minimum fluorescence in the dark ( inline image) to inline image as both the most accurate in situ measurement of inline image, and the methodology best suited for highly resolved autonomous inline image measurements.

CCD photometry of distant comets II

R band CCD photometric observations of short period Jupiter family comets in the heliocentric region of 2.11 AU less than or equal to R-h less than or equal to 5.63 AU were performed using the 4.2 m William Herschel Telescope on La Palma in December 1998. 22 comets were targeted, including the comet- asteroid transition object 49P/Arend-Rigaux. Out of a total of ten detected comets. six were seen to display substantial outgassing (48P, 65P, 74P, 103Pt 128P, and 139P), with the remaining four comets (7P. 9P, 22P. and 49P) being stellar in appearance. Nuclear radius measurements and relative dust production rates in terms of Af rho were measured for these comets, along with upper limits for the remaining twelve undetected comets (6P, 44P, 51P, 54P, 57P: 63P, 71P, 73P, 79P, 86P, 87P, and 100P). The inactive comets had nuclear radii in the range 1.8 km less than or equal to r(N) less than or equal to 4.4 km, while upper limits for the active and undetected comets (assuming they all lay within the held of view) were between 0.6 km and 12.7 km, for an assumed albedo of 0.04. Even if one applies the previously measured maximum axis ratio of 2.6:1 and the minimum measured albedo of 0.02 to the undetected comets. their projected semi-major axes are all constrained to below 8 km. For the active comets, photometric profiles of their dust comae were measured and are consistent with those of steady state coma models.

Multi-ionization of helium and lithium using the independent electron and independent event models with intrinsic CDW

Cross sections for the multi-ionization of He and Li are presented for impact energies in the range of 50 to 1000 keV/amu. These are calculated using the eikonal initial state approximation to represent the input and exit channels of the active electrons. The ionization process is simulated in a variety of ways, most notably an attempt to account for the effects of electron correlation via the inclusion of a continuum density of states (CDS) term. Inadequacies, of the CDW formulation at small impact parameters, and of the models themselves, are discussed and conclusions are drawn on what repercussions this has for the cross sections calculated.

Clinical Determinants of Response to Irinotecan-Based Therapy Derived from Cell Line Models

Purpose: In an attempt to identify genes that are involved in resistance to SN38, the active metabolite of irinotecan (also known as CPT-11), we carried out DNA microarray profiling of matched HCT116 human colon cancer parental cell lines and SN38-resistant cell lines following treatment with SN38 over time.