7,396 research outputs found

    Definition of smolder experiments for Spacelab

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    The feasibility of conducting experiments in space on smoldering combustion was studied to conceptually design specific smoldering experiments to be conducted in the Shuttle/Spacelab System. Design information for identified experiment critical components is provided. The analytical and experimental basis for conducting research on smoldering phenomena in space was established. Physical descriptions of the various competing processes pertaining to smoldering combustion were identified. The need for space research was defined based on limitations of existing knowledge and limitations of ground-based reduced-gravity experimental facilities

    Behavioural interventions for weight management in pregnancy: A systematic review of quantitative and qualitative data

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    Objective: To assess the effectiveness of dietary with or without physical activity interventions to prevent excessive weight gain in pregnancy and explore the factors that influence intervention effectiveness. Design: Systematic review, including a meta-analysis of controlled trials of interventions to prevent excessive weight gain during pregnancy and a thematic synthesis of qualitative studies that investigated the views of women on weight management during pregnancy. Data sources: Eleven electronic bibliographic databases, reference list of included studies, relevant review articles and experts in the field. Review methods: Two independent reviewers extracted data. RevMan software was used to perform the meta-analyses. Qualitative data was subject to thematic analysis. Both quantitative and qualitative data were aligned using a matrix framework. Results: Five controlled trials and nine qualitative studies were included. The overall pooled effect size found no significant difference in gestational weight gain amongst participants in the interventions group compared with the control group (mean difference -1.88kg CI -4.34 to 0.59). The study designs, participants and interventions all varied markedly and there was significant heterogeneity within this comparison in the meta-analysis (I2 76%). Subgroup and sensitivity analysis did not identify contextual elements that influenced the effectiveness of the intervention. In a thematic analysis of the qualitative studies, three major themes emerged relating to women’s views of weight management in pregnancy; pregnancy as a time of transition and change, conflicting and contradictory messages, a perceived lack of control. When the results of both quantitative and qualitative data were aligned it was clear that some of the barriers that women described in achieving healthy weight gain in pregnancy were not addressed by the interventions evaluated. This may have contributed to the limited effectiveness of the interventions. Conclusions: Despite intense and often tailored interventions there was no statistically significant effect on weight gain during pregnancy. Inadequate and often contradictory information regarding healthy weight management was reported by women in qualitative studies and this was addressed in the interventions but in itself was insufficient to lead to reduced weight gain. Multiple types of interventions, including community based strategies, are needed to address this complex health problem

    Patterning molecular scale paramagnets at Au Surface: A root to Magneto-Molecular-Electronics

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    Few examples of the exploitation of molecular magnetic properties in molecular electronics are known to date. Here we propose the realization of Self assembled monolayers (SAM) of a particular stable organic radical. This radical is meant to be used as a standard molecule on which to prove the validity of a single spin reading procedure known as ESR-STM. We also discuss a range of possible applications, further than ESR-STM, of magnetic monolayers of simple purely organic magnetic molecule.Comment: This preprint is currently partially under revisio

    Nonequilibrium Casimir-Polder Force in Non-Stationary Systems

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    Recently the Casmir-Polder force felt by an atom near a substrate under nonequilibrium stationary conditions has been studied theoretically with macroscopic quantum electrodyanamics (MQED) and verified experimentally with cold atoms. We give a quantum field theory derivation of the Langevin equation describing the atom's motion based on the influence functional method valid for fully nonequilibrium (nonstationary) conditions. The noise associated with the quantum field derived from first principles is generally colored and nonlocal, which is at variance with the `local source hypothesis' of MQED's generalization to nonequilibrium conditions. Precision measurements on the shape deformation of an atomic gas as a function of its distance from a mirror would provide a direct check of our predictions based on this Langevin equation.Comment: Rewritten Introduction and Abstract in v2 with a slightly altered title to place a sharper focus of our goals and a clearer distinction of what the influence functional method can achieve beyond the macroscopic QED approach. The rest of the paper and the results remain the sam

    Industry 4.0 and world class manufacturing integration: 100 technologies for a WCM-I4.0 matrix

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    In the last decade, technological progress has profoundly influenced the industrial world and all industrial sectors have been confronted with a change in technological paradigms. In such a context, this study aims to analyze the synergies between the technological world of Industry 4.0 and the purely organizational and managerial domain ofWorld Class Manufacturing, a model of Operational Excellence. The objective is relating the driving dimensions of the World Class Manufacturing (WCM) system to the technological macrocategories of Industry 4.0: this would allow the identification of which technological solution to leverage on, aiming at optimization in a given World Class Manufacturing pillar. The result is a "WCM-I4.0 matrix": a proposal to reconcile, exploit and trace the relations between the two complex concepts. The WCM-I4.0 matrix includes, by now, 100 Industry 4.0 technologies that best suits with the World Class Manufacturing pillars

    Polyelectrolyte Multilayering on a Charged Planar Surface

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    The adsorption of highly \textit{oppositely} charged flexible polyelectrolytes (PEs) on a charged planar substrate is investigated by means of Monte Carlo (MC) simulations. We study in detail the equilibrium structure of the first few PE layers. The influence of the chain length and of a (extra) non-electrostatic short range attraction between the polycations and the negatively charged substrate is considered. We show that the stability as well as the microstructure of the PE layers are especially sensitive to the strength of this latter interaction. Qualitative agreement is reached with some recent experiments.Comment: 28 pages; 11 (main) Figs - Revtex4 - Higher resolution Figs can be obtained upon request. To appear in Macromolecule

    Feasibility of high-voltage systems for a very long drift in liquid argon TPCs

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    Designs of high-voltage (HV) systems for creating a drift electric field in liquid argon TPCs are reviewed. In ongoing experiments systems capable of approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of up to 1.5 m. Two of them having different approaches are presented: (1) the ICARUS-T600 detector having a system consisting of an external power supply, HV feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For a giant scale liquid argon TPC, a system providing 2 MV may be required to attain a drift length of approx. 20 m. Feasibility of such a system is evaluated by extrapolating the existing designs.Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba (Japan), March 201

    Stable crystalline lattices in two-dimensional binary mixtures of dipolar particles

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    The phase diagram of binary mixtures of particles interacting via a pair potential of parallel dipoles is computed at zero temperature as a function of composition and the ratio of their magnetic susceptibilities. Using lattice sums, a rich variety of different stable crystalline structures is identified including AmBnA_mB_n structures. [AA (B)(B) particles correspond to large (small) dipolar moments.] Their elementary cells consist of triangular, square, rectangular or rhombic lattices of the AA particles with a basis comprising various structures of AA and BB particles. For small (dipolar) asymmetry there are intermediate AB2AB_2 and A2BA_2B crystals besides the pure AA and BB triangular crystals. These structures are detectable in experiments on granular and colloidal matter.Comment: 6 pages - 2 figs - phase diagram update

    Nonlocal properties of entangled two-photon generalized binomial states in two separate cavities

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    We consider entangled two-photon generalized binomial states of the electromagnetic field in two separate cavities. The nonlocal properties of this entangled field state are analyzed by studying the electric field correlations between the two cavities. A Bell's inequality violation is obtained using an appropriate dichotomic cavity operator, that is in principle measurable.Comment: 5 pages, 1 figur
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