Compartmentalized storage tank for electrochemical cell system

A compartmentalized storage tank is disclosed. The compartmentalized storage tank includes a housing, a first fluid storage section disposed within the housing, a second fluid storage section disposed within the housing, the first and second fluid storage sections being separated by a movable divider, and a constant force spring. The constant force spring is disposed between the housing and the movable divider to exert a constant force on the movable divider to cause a pressure P1 in the first fluid storage section to be greater than a pressure P2 in the second fluid storage section, thereby defining a pressure differential

Constant-Differential-Pressure Two-Fluid Accumulator

A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system

Jean-Luc Nancy and the hospital : imagining clinical environments of strangeness and multiplicity

This article explores representations of illness and medical treatment in the work of Jean-Luc Nancy, arguing that his philosophy urges us to re-imagine healthcare environments and hospital spaces. In L’Intrus (2000), Nancy describes how undergoing a heart transplant led him to encounter the intrinsic strangeness and multiplicity of his body and identity. This text, it will be seen, explores also the spatialization of this strangeness and multiplicity; Nancy characterizes the transplant as an ‘intrusion’ and details the extension of his body and being across a network of medical treatments and technologies. This article brings L’Intrus into dialogue with approaches to hospital environments in the medical humanities, as well as with Nancy’s interrogation of conceptions of construction, destruction, and ‘struction’ in Dans quels mondes vivons-nous? (2011). It proposes that Nancy’s work invites us to rethink clinical environments as spaces which must embrace, rather than resist, strangeness and multiplicity. Résumé: Cet article explore des représentations de la maladie et des soins médicaux à travers le travail de Jean-Luc Nancy, argumentant que sa philosophie nous pousse à réimaginer les environnements des soins de santé et les espaces hospitaliers. Dans L’Intrus (2000), Nancy décrit la façon dont le fait de subir une greffe cardiaque l’a mené à rencontrer l’étrangeté et la multiplicité intrinsèques à son corps et à son identité. Ce texte, nous le verrons, explore aussi la spatialisation de cette étrangeté et de cette multiplicité; Nancy caractérise la greffe comme une ‘intrusion’ et détaille l’extension de son corps et de son être à travers un réseau de soins et de technologies médicaux. Cet article fait dialoguer L’Intrus avec des approches des environnements hospitaliers dans les humanités médicales, ainsi qu’avec la pensée de Nancy autour des concepts de la construction, de la destruction, et de la ‘struction’ dans Dans quels mondes vivons-nous? (2011). Nous proposerons que le travail de Nancy nous invite à repenser les environnements cliniques, les considérant comme des espaces non pas pour résister mais pour accueillir l’étrangeté et la multiplicité

Plasticity and Formlessness between Malabou and Bataille

This article stages an encounter between Catherine Malabou’s plasticité and Georges Bataille’s informe. Malabou’s transdisciplinary philosophy of plasticity observes the mutability and transformability of all forms, from aesthetic forms to the neuroplastic form of the human brain. By contrast, Bataille’s informe implies that the universe is radically formless and that all attempts to give form to it are doomed. While Malabou’s plastic approach to form and Bataille’s ideological suspicion of all form might initially seem irreconcilable, this article argues that these concepts in fact intersect dynamically, developing plastic-formless approaches to form, both aesthetic and organic, between the two thinkers

Fundamentals of the logarithmic measure for revealing multimodal diffusion

We develop a theoretical foundation for a time-series analysis method suitable for revealing the spectrum of diffusion coefficients in mixed Brownian systems, for which no prior knowledge of particle distinction is required. This method is directly relevant for particle tracking in biological systems, in which diffusion processes are often nonuniform. We transform Brownian data onto the logarithmic domain, in which the coefficients for individual modes of diffusion appear as distinct spectral peaks in the probability density. We refer to the method as the logarithmic measure of diffusion, or simply as the logarithmic measure. We provide a general protocol for deriving analytical expressions for the probability densities on the logarithmic domain. The protocol is applicable for any number of spatial dimensions with any number of diffusive states. The analytical form can be fitted to data to reveal multiple diffusive modes. We validate the theoretical distributions and benchmark the accuracy and sensitivity of the method by extracting multimodal diffusion coefficients from two-dimensional Brownian simulations of polydisperse filament bundles. Bundling the filaments allows us to control the system nonuniformity and hence quantify the sensitivity of the method. By exploiting the anisotropy of the simulated filaments, we generalize the logarithmic measure to rotational diffusion. By fitting the analytical forms to simulation data, we confirm the method's theoretical foundation. An error analysis in the single-mode regime shows that the proposed method is comparable in accuracy to the standard mean-squared displacement approach for evaluating diffusion coefficients. For the case of multimodal diffusion, we compare the logarithmic measure against other, more sophisticated methods, showing that both model selectivity and extraction accuracy are comparable for small data sets. Therefore, we suggest that the logarithmic measure, as a method for multimodal diffusion coefficient extraction, is ideally suited for small data sets, a condition often confronted in the experimental context. Finally, we critically discuss the proposed benefits of the method and its information content

Conformational isomerization dynamics in solvent violates both the Stokes-Einstein relation and Kramers' theory

Molecular isomerization kinetics in liquid solvents are determined by a complex interplay between the friction acting on a rotating dihedral due to interactions with the solvent, internal dissipation effects (also known as internal friction), the viscosity of the solvent, and the free energy profile over which a dihedral rotates. Currently, it is not understood how these quantities are related at the molecular scale. Here, we combine molecular dynamics simulations of isomerizing n-alkane chains and dipeptide molecules in mixed water-glycerol solvents with memory-kernel extraction techniques to directly evaluate the frequency-dependent friction acting on a rotating dihedral. We extract the friction and isomerization times over a range of glycerol concentrations and accurately evaluate the relationships between solvent viscosity, isomerization kinetics, and dihedral friction. We show that the total friction acting on a rotating dihedral does not scale linearly with solvent viscosity, thus violating the Stokes-Einstein relation. Additionally, we demonstrate that the kinetics of isomerization are significantly faster compared to the Kramers prediction in the overdamped limit. We suggest that isomerization kinetics are determined by the multi-time-scale friction coupling between a rotating dihedral and its solvent environment, which results in non-Markovian kinetic speed-up effects.Comment: 9 pages, 4 figure

Audio-based localization for ubiquitous sensor networks

Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2005.Includes bibliographical references (p. 97-101).This research presents novel techniques for acoustic-source location for both actively triggered, and passively detected signals using pervasive, distributed networks of devices, and investigates the combination of existing resources available in personal electronics to build a digital sensing 'commons'. By connecting personal resources with those of the people nearby, tasks can be achieved, through distributed placement and statistical improvement, that a single device could not do alone. The utility and benefits of spatio-temporal acoustic sensing are presented, in the context of ubiquitous computing and machine listening history. An active audio self-localisation algorithm is described which is effective in distributed sensor networks even if only coarse temporal synchronisation can be established. Pseudo-noise 'chirps' are emitted and recorded at each of the nodes. Pair-wise distances are calculated by comparing the difference in the audio delays between the peaks measured in each recording. By removing dependence on fine grained temporal synchronisation it is hoped that this technique can be used concurrently across a wide range of devices to better leverage the existing audio sensing resources that surround us.(cont.) A passive acoustic source location estimation method is then derived which is suited to the microphone resources of network-connected heterogeneous devices containing asynchronous processors and uncalibrated sensors. Under these constraints position coordinates must be simultaneously determined for pairs of sounds and recorded at each microphone to form a chain of acoustic events. It is shown that an iterative, numerical least-squares estimator can be used. Initial position estimates of the source pair can be first found from the previous estimate in the chain and a closed-form least squares approach, improving the convergence rate of the second step. Implementations of these methods using the Smart Architectural Surfaces development platform are described and assessed. The viability of the active ranging technique is further demonstrated in a mixed-device ad-hoc sensor network case using existing off-the-shelf technology. Finally, drawing on human-centric onset detection as a means of discovering suitable sound features, to be passed between nodes for comparison, the extension of the source location algorithm beyond the use of pseudo-noise test sounds to enable the location of extraneous noises and acoustic streams is discussed for further study.Benjamin Christopher Dalton.S.M

Crafting Stories in the Domestic Archive

The Knitting and Crochet Guild archive, Holmfirth, West Yorkshire hosts a vast array of hand-made items, including clothing, artefacts, yarns and samples, as well as tools, pattern leaflets, booklets and magazines. This article explores how the collection was used as a starting point for engaging students in new experiential encounters with the archive, as both a concept and as a container for material histories of the past. Two theoretical frameworks of investigation provide an intertwining methodology for reading the project: the first operates as a feminist narrative of intervention in the history of textile craft making, and the second considers how the ‘thought-images’ of Walter Benjamin provide a tool for thinking through student responses. It is argued that as a repository of the home-crafts, Lee Mills provides historical materialism with the experiential investigation it needs for a critical pedagogy of the present

Fast protein folding is governed by memory-dependent friction

When described by a low-dimensional reaction coordinate, the folding rates of most proteins are determined by a subtle interplay between free-energy barriers, which separate folded and unfolded states, and friction. While it is commonplace to extract free-energy profiles from molecular trajectories, a direct evaluation of friction is far more elusive and typically relies on fits of measured reaction rates to memoryless reaction-rate theories. Here, using memory-kernel extraction methods founded on a generalized Langevin equation (GLE) formalism, we directly calculate the time-dependent friction acting on the fraction of native contacts reaction coordinate Q, evaluated for eight fast-folding proteins, taken from a published set of large-scale molecular dynamics protein simulations. Our results reveal that, across the diverse range of proteins represented in this dataset, friction is more influential than free-energy barriers in determining protein folding rates. We also show that proteins fold in a regime where the finite decay time of friction significantly reduces the folding times, in some instances by as much as a factor of 10, compared to predictions based on memoryless friction