In this paper we report on the timing resolution obtained in a beam test with pions of 180 GeV/c momentum at CERN for the first production of 45 μm thick Ultra-Fast Silicon Detectors (UFSD). UFSD are ...based on the Low- Gain Avalanche Detector (LGAD) design, employing n-on-p silicon sensors with internal charge multiplication due to the presence of a thin, low-resistivity diffusion layer below the junction. The UFSD used in this test had a pad area of 1.7 mm2. The gain was measured to vary between 5 and 70 depending on the sensor bias voltage. The experimental setup included three UFSD and a fast trigger consisting of a quartz bar readout by a SiPM. The timing resolution was determined by doing Gaussian fits to the time-of-flight of the particles between one or more UFSD and the trigger counter. For a single UFSD the resolution was measured to be 34 ps for a bias voltage of 200 V, and 27 ps for a bias voltage of 230 V. For the combination of 3 UFSD the timing resolution was 20 ps for a bias voltage of 200 V, and 16 ps for a bias voltage of 230 V.
The theoretical description of the adsorption of surfactants at interfaces between aqueous solutions and oil was based over a very long time on models derived for the solution/air interface. Thus, ...most of the experimentally observed peculiarities could not be specifically considered but were merely interpreted in terms of a penetration of oil molecules into the alkyl chain layer of the adsorbed surfactant molecules. These penetrating oil molecules enhance the surfactant adsorption as compared to the water/air interface. Later on, for the special situations at water/oil interfaces a competitive adsorption of surfactant and oil molecules was postulated, allowing a much better description of experimental data. This picture, however, was unable to explain why the interfacial tension of the water/oil interface decreases very quickly when extremely small amounts of surfactants are added to the water. This effect cannot be of competitive nature, but a cooperativity of surfactant and oil molecules forming a mixed adsorption layer is required instead. This cooperative effect means that already few surfactant molecules adsorbed at the interface can induce a significant ordering of oil molecules in the interfacial layer. This new interfacial structure, in turn, attracts further surfactant molecules to adsorb. Improving the theoretical description of experimental data was finally achieved by applying suitable adsorption models for the two adsorbing compounds, i.e. a Frumkin adsorption model for the oil molecules and a Langmuir, Frumkin, or reorientation model for the adsorbing surfactant molecules. Here, the progress in modelling surfactant adsorption at water/oil interfaces is discussed mainly for the homologous series of the cationic surfactants CnTAB, of the anionic surfactant SDS, and members of the homologous series of the non-ionic surfactants CnDMPO at water/alkane interfaces.
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•Surfactants adsorb at the water/oil interface at much lower bulk concentrations as compared to the water/air interface.•At very low concentrations surfactant and oil molecules adsorb in a cooperative way.•With increasing concentration surfactant and oil molecules compete at the interface.•Depending on the packing structure of surfactants, oil molecules are squeezed out from the interfacial layer.•A thermodynamic model allows describing all states of the mixed adsorption layer.
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In order to understand the basic mechanisms affecting emulsion stability, the intrinsic dynamics of the drop population must be investigated. We hypothesize that transient ballistic ...motion can serve as a marker of interactions between drops. In 1G conditions, buoyancy-induced drop motion obscures these interactions. The microgravity condition onboard the International Space Station enable this investigation.
We performed Diffusing Wave Spectroscopy (DWS) experiments in the ESA Soft Matter Dynamics (SMD) facility. We used Monte Carlo simulations of photon trajectory to support data analysis. The analysis framework was validated by ground-based characterizations of the initial drop size distribution (DSD) and the properties of the oil/water interface in the presence of surfactant.
We characterized the drop size distribution and found to be bi-disperse. Drop dynamics shows transient ballistic features at early times, reaching a stationary regime of primarily diffusion-dominated motion. This suggests different ageing mechanisms: immediately after emulsification, the main mechanism is coalescence or aggregation between small drops. However at later times, ageing proceeds via coalescence or aggregation of small with large drops in some emulsions. Our results elucidate new processes relevant to emulsion stability with potential impact on industrial processes on Earth, as well as enabling technologies for space exploration.
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•Diffusing Wave Spectroscopy is used to characterize a paradigmatic emulsion of low surfactant content (i.e. well below CMC).•Three regimes of ageing, with a power law growth of the ...mechanical modulus, probably related to water drainage.•As a function of surfactant content, a peak of interfacial dilational-modulus matches a similar peak of bulk shear-modulus.•We infer that mechanisms (de)stabilizing emulsions may be explained in terms of microscopic processes.
We employ Diffusing Wave Spectroscopy (DWS) to characterize microscopic structure, internal dynamics and rheological properties of a paradigmatic emulsion formed by water and dodecane stabilized by the anionic surfactant Sodium Dodecyl Sulfate (SDS).
We focus on ageing and stability in the regime of low surfactant concentration, well below the Critical Micellar Concentration (CMC). In the long-time ageing regimes differentiate in stable and unstable, depending on surfactant concentration. For the stable case, ageing affects the dynamics following a power law with an exponent independent on surfactant concentration, presumably related to the late stages of the water drainage process. On the contrary, at constant ageing, the dependence of the dynamics from surfactant concentration shows a slowdown, corresponding to a maximum in the bulk shear mechanical modulus, around SDS=2mM which is reminiscent of a similar maximum found by drop tensiometry in the dilational modulus of the single interface.
This suggests a consistent picture of the mechanisms (de)stabilizing the emulsion, explained in terms of elementary process at the interface. These results show furthermore that DWS can be a reliable diagnostic for the study of the aging and of the mechanical properties of concentrate emulsions. This might be relevant to control stability of emulsions when a low concentration of surfactant is desired, e.g. for economical or environment reasons.
The interfacial tension response to dilational deformation of interfacial area exhibits a (more or less) nonlinear behavior, depending on the amplitude of the deformation. Studies of such observable ...interfacial properties in the nonlinear domain suggest valuable information about the two-dimensional microstructure of the interfacial layer, as well as about the structure time-evolution.
In this article, the emphasis is centered on the available mathematical methods for quantitatively analyzing and describing the magnitude and the characteristics of the nonlinear interfacial viscoelastic properties. Specifically, in periodic oscillation experiments the nonlinear behavior can be represented by the combination of a linear part (the surface dilational modulus), with an additional complementary Fourier analysis parameterizing the nonlinearity. Also asymmetric Lissajous plots, of interfacial tension versus deformation, are useful tools for expanding the response nonlinearity into four distinct components relevant to significant points of the cyclic loop.
In connection with the mathematical methods, nonequilibrium thermodynamic formulations provide a powerful theoretical framework for investigating the interfacial dynamic properties of multiphase systems.
Experimental results for adsorption layers of complex components, available in the literature, show notable nonlinear interfacial viscoelastic behavior. In particular in this review, data are illustrated for solutions of polymers and of polyelectrolyte/surfactant complexes.
The observed nonlinear findings reveal formation of complexes, patches, and other different interfacial structures.
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•Application of mathematical methods effectively describes nonlinearity magnitude.•Spectrum characterizes the nonlinear interfacial response in oscillation experiments.•Lissajous plot quantifies the degree of nonlinearity in interfacial periodic responses.•Complex substances give rise to notable nonlinear interfacial rheological properties.
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•Dynamics of emulsions in microgravity will be studied by DWS in the “Soft Matter Dynamics” facility of the International Space Station.•In view of these experiments, a ground ...prototype of DWS instrument is presented and discussed.•The accuracy of DWS correlation function thus obtained is evaluated theoretically and compared with the experimentally determined variance.•An objective criterion is proposed to determine time/frequency limits of application of DWS technique.
Diffusing Wave Spectroscopy (DWS) is a technique used to characterize microscopic structure and rheological properties of turbid samples. This is achieved by analyzing the time evolution of coherence speckles of light that has been multiply scattered within the sample. One attractive feature of DWS is that it is non-invasive, and robust. For this reason, DWS has been selected as a diagnostic tool for an experiment module uploaded onboard the International Space Station (ISS) and devoted to the study of soft matter dynamics –related phenomena, among which, the basic mechanisms responsible for emulsions and foams aging. Moreover, the sensitivity of DWS to tiny motions and to fast time scales allows to extend measurements beyond the limits of usual rheological techniques, of micro-imaging and related techniques. However, the accuracy obtainable by DWS measurements is often limited.
Here we revise different experimental approaches to the characterization of emulsions by DWS. We provide quantification of the accuracy of the correlation functions and we discuss how this affects the determination of the mechanical moduli, providing an objective criterion to establish the time window over which DWS results are reliable. These concepts are applied to discuss a laboratory prototype and to address the design of the DWS diagnostics suitable for the emulsion studies to be performed onboard the ISS.
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•Social multicriteria evaluation provides insights for policy planning in threatened cultural landscapes.•Biophysical and social evaluations of ecosystem services provide different ...results.•A “mosaic scenario” of land uses appeared as the most desired scenario in terms of supplying multiple ecosystem services.•Combination of social multicriteria evaluation and ecosystem services framework is a highly promising tool to support co-creation of knowledge for decision-making.
Mediterranean cultural landscapes are currently undergoing intense transformations, resulting in a polarization of land uses across an intensification-abandonment continuum. This transformation is characterized by uncertain and non-linear interactions and impacts on ecosystem services and human wellbeing. Our study focuses on a particular multifunctional Mediterranean cultural landscape composed of different land uses (i.e., dehesas, olive groves, pine forests, Mediterranean forests and scrublands) in the Sierra Morena mountain range (Jaén, Spain), which is undergoing a rapid process of land use change.
In this context, the involvement of local stakeholders through participatory processes is critical for proper landscape management and decision-making. The aim of this paper is to combine Social Multicriteria Evaluation (SMCE) and ecosystem services frameworks for an assessment of likely future scenarios under different drivers of land use change, analysing how such changes would affect people living or making use of ecosystem services.
Among four plausible future scenarios, the so-called “Mosaic landscape” scenario was widely recognized as the most desirable future landscape configuration for Sierra Morena, as it allows the supply of a balanced flow of ecosystem services and reduces ecosystem services trade-offs and conflicts among stakeholders. The combination of social multicriteria evaluation with the ecosystem services framework and future scenario analysis allows a robust co-creation of knowledge and provides insights pertinent to participatory management of cultural landscapes and stakeholders’ relationships through a socially relevant but also rigorous methodology.
A methodological framework is proposed for participatory scenario development on the basis of evidence from the literature, and is tested and refined through the development of scenarios for the ...future of UK uplands. The paper uses a review of previous work to justify a framework based around the following steps: i) define context and establish whether there is a basis for stakeholder engagement in scenario development; ii) systematically identify and represent relevant stakeholders in the process; iii) define clear objectives for scenario development with stakeholders including spatial and temporal boundaries; iv) select relevant participatory methods for scenario development, during initial scenario construction, evaluation and to support decision-making based on scenarios; and v) integrate local and scientific knowledge throughout the process. The application of this framework in case study research suggests that participatory scenario development has the potential to: i) make scenarios more relevant to stakeholder needs and priorities; ii) extend the range of scenarios developed; iii) develop more detailed and precise scenarios through the integration of local and scientific knowledge; and iv) move beyond scenario development to facilitate adaptation to future change. It is argued that participatory scenario development can empower stakeholders and lead to more consistent and robust scenarios that can help people prepare more effectively for future change.
•A methodological framework is proposed develop scenarios with stakeholders that can inform decision-making.•This has the potential to empower stakeholders and make scenarios more relevant to their needs.•Integrating local and scientific knowledge can increase the diversity, detail and precision of scenarios.•In this way, more consistent and robust scenarios can be developed to help people prepare more effectively for future change.
Photocatalytic oxidation (PCO) could provide energy-efficient purification of water and air. Its efficacy is constrained mainly by limited photocatalytic activity and active surface. To address both, ...solid foams with hierarchic porous structures spanning multiple length-scales, stabilized by photocatalytic Zn-doped titania nanoparticles (NP) were synthesized and tested. The NP were characterized by SEM, EDS, DLS, XRD, Raman and UV–Vis spectroscopies. Solid foams were stabilized by NP complexes with cationic surfactants. The foam morphology was characterized and photocatalytic activity was demonstrated in water. The present work paves the way for the development of efficient systems for air and water purification in demanding technological sectors, such as aerospace.
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•Synthesis of Zn-doped anatase titania nanoparticles.•Characterization of their morphology, crystalline structure, and optical properties.•Demonstration of their PCO activity.•Formation of amphiphilic complexes with cationic surfactant CTAB.•Formation and characterization of foams stabilized by these amphiphilic complexes.
Autoantibody against phospholipase A2 receptor (anti-PLA2R) is a sensitive and specific biomarker of idiopathic membranous nephropathy (iMN), being found in approximately 70% of iMN patients and only ...occasionally in other glomerular diseases. However, whereas its diagnostic specificity vs. normal controls and other glomerulonephritides (GN) has been firmly established, its specificity vs. membranous nephropathy associated with various diseases (sMN) has given inconsistent results. The aim of our study was to evaluate the prevalence of anti-PLA2R antibodies in iMN in comparison with various control groups, including sMN. A total of 252 consecutive iMN patients, 184 pathological and 43 healthy controls were tested for anti-PLA2R antibody using indirect immunofluorescence (PLA2R IIFT, Euroimmun). Anti-PLA2R autoantibodies were detectable in 178/252 iMN patients, 1/80 primary GN, 0/72 secondary GN, 9/32 sMN and 0/43 healthy controls, with a diagnostic sensitivity of 70.6%. The diagnostic specificity of anti-PLA2R antibody vs. normal and pathological controls was 100 and 94.6% respectively. However, when the diagnostic specificity was calculated only vs. secondary forms of MN, it decreased considerably to 71.9%. Interestingly enough, 9 out of 10 anti-PLA2R positive patients in the disease control groups had membranous nephropathy associated with various diseases (7 cancer, 1 Crohn’s disease, 1 scleroderma). In conclusion, anti-PLA2R positivity in a patient with MN, should not be considered sufficient to abstain from seeking a secondary cause, especially in patients with risk factors for neoplasia. The causal relationship between tumors and anti-PLA2R-induced MN remains to be established, as well as the possible mechanisms through which malignancies provoke autoimmunity.
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