Technical Note: Evaporation of polar stratospheric cloud particles, in situ, in a heated inlet

International audienceIn December 2001 and 2002 in situ aerosol measurements were made from balloon-borne platforms within polar stratospheric clouds (PSC) which contained particles of supercooled ternary solution (STS), nitric acid trihydrate (NAT) and ice. Particle size and number concentrations were measured with two optical particle counters. One of these included an ~80cm inlet heated to K to evaporate the PSC particles and thus to obtain measurements, within PSCs, of the size distribution of the particles upon which the PSCs condensed. These measurements are compared to models, described here, that calculate the evaporation of PSC particles at and for an inlet transition time of about 0.1s. The modeled evaporation for STS agrees well with the measurements. For NAT the modeled evaporation is less than the evaporation measured. The primary uncertainty concerns the phase and morphology of NAT particles as they are brought to temperatures >50K above equilibrium temperatures for NAT at stratospheric partial pressures. The slow evaporation of NAT in heated inlets could be used to identify a small NAT component within a mixed phase PSC dominated by STS

Sustainability analysis of the CITYLAB solutions

The objective of the CITYLAB project is to develop knowledge and solutions that result in roll-out, upscaling and further uptake of cost effective strategies, measures and tools for emission free city logistics. CITYLAB includes a set of Living Laboratories where promising logistic concepts are implemented related to emissions free city logistics. The objective of this report is to assess the impact that would occur when the CITYLAB implementations would be scaled up. The main challenge that has to be overcome is the difference in type, availability and detail of data from different CITYLAB implementations. This assessment of the impacts of upscaling is done by integrating all stakeholders’ opinions in the evaluation process and taking into account the costs and benefits for society as well as the financial viability for industry partners

Ice Initiation by Aerosol Particles: Measured and Predicted Ice Nuclei Concentrations versus Measured Ice Crystal Concentrations in an Orographic Wave Cloud

The initiation of ice in an isolated orographic wave cloud was compared with expectations based on ice nucleating aerosol concentrations and with predictions from new ice nucleation parameterizations applied in a cloud parcel model. Measurements of ice crystal number concentrations were found to be in good agreement both with measured number concentrations of ice nuclei feeding the clouds and with ice nuclei number concentrations determined from the residual nuclei of cloud particles collected by a counterflow virtual impactor. Using lognormal distributions fitted to measured aerosol size distributions and measured aerosol chemical compositions, ice nuclei and ice crystal concentrations in the wave cloud were reasonably well predicted in a 1D parcel model framework. Two different empirical parameterizations were used in the parcel model: a parameterization based on aerosol chemical type and surface area and a parameterization that links ice nuclei number concentrations to the number concentrations of particles with diameters larger than 0.5 μm. This study shows that aerosol size distribution and composition measurements can be used to constrain ice initiation by primary nucleation in models. The data and model results also suggest the likelihood that the dust particle mode of the aerosol size distribution controls the number concentrations of the heterogeneous ice nuclei, at least for the lower temperatures examined in this case

Case studies: results and synthesis projet 7FP CLOSER (Connecting LOng and Short-distance networks for Efficient Transport) Rapport de recherche Deliverable 5.2 project européen CLOSER.

The CLOSER project has been set to analyse the interfaces and interconnectionsbetween long distance transport networks and local/regional transport networks of allmodes. The project is funded within the Seventh Framework Programme of theEuropean Commission, under the topic TPT-2008.0.0.13 “New mobility/organisationalschemes: interconnection between short and long-distance transport networks”.The objective of WP5 of CLOSER is to accomplish in-depth case studies to deepenand validate the understanding of results obtained in Work packages 2, 3 and 4. Thiswill be achieved by:- Developing a joint assessment and evaluation framework for the case studies,incorporating knowledge that has been obtained in WP 2, WP 3 and WP 4- Carrying out the case studies- Synthesising the results of the case studies in order to give inputs for thedevelopment of recommendations in WP 6.The deliverable at hand summarises the seven case studies that have been conductedin the CLOSER project: Leipzig-Halle airport (Germany) Armentiéres station (France) Oslo bus terminal Vaterland (Norway) Port of Helsinki (Finland) Thessaloniki port (Greece) Constantza port (Romania) Vilnius Airport (Lithuania

Impact and process assessment of the seven CITYLAB implementations

CITYLAB focuses on four axes that call for improvement and intervention: •Highly fragmented last-mile deliveries in city centres •Inefficient deliveries to large freight attractors and public administrations •Urban waste, return trips and recycling •Logistics sprawl Within these axes, the project supports seven implementations that are being tested, evaluated and rolled out. An implementation is defined as the process of preparing, testing and putting into practice a new service or a new way of operating or organising logistics activities. The objective of this report is to present an assessment of the effects and consequences of the implementations as they are conducted. For each case, we summarise the process leading to the application of a specific technical and managerial solution, and present the outcomes. For each implementation, we present •Problem and aim •Description of the solution •Implementation process •Effects and consequences •Challenges ahead •Lessons and generalisation of results This deliverable provides a complete picture of the evolvement of the implementations during the CITYLAB project and final versions of the process and impact assessment

Mass balance and hydrological modeling of the Hardangerjøkulen ice cap in south-central Norway

A detailed, physically based, one dimensional column snowpack model (Crocus) has been incorporated into the hydrological model, Weather Research and Forecasting (WRF)-Hydro, to allow for direct surface mass balance simulation of glaciers and subsequent modeling of meltwater discharge from glaciers. The new system (WRF-Hydro/Glacier) is only activated over a priori designated glacier areas. This glacier area is initialized with observed glacier thickness and assumed to be pure ice (with corresponding ice density). This allows for melting of the glacier to continue after all accumulated snow has melted. Furthermore, the simulation of surface albedo over the glacier is more realistic, as surface albedo is represented by snow, where there is accumulated snow, and glacier ice, when all accumulated snow is melted. To evaluate the WRF-Hydro/Glacier system over a glacier in southern Norway, WRF atmospheric model simulations were downscaled to 1 km grid spacing. This provided meteorological forcing data to the WRF-Hydro/Glacier system at 100 m grid spacing for surface and streamflow simulation. Evaluation of the WRF downscaling showed a good comparison with in situ meteorological observations for most of the simulation period. The WRF-Hydro/Glacier system reproduced the glacier surface winter/summer and net mass balance, snow depth, surface albedo and glacier runoff well compared to observations. The improved estimation of albedo has an appreciable impact on the discharge from the glacier during frequent precipitation periods. We have shown that the integrated snowpack system allows for improved glacier surface mass balance studies and hydrological studies

Linear-time protein 3-D structure searching with insertions and deletions

<p>Abstract</p> <p>Background</p> <p>Two biomolecular 3-D structures are said to be similar if the RMSD (root mean square deviation) between the two molecules' sequences of 3-D coordinates is less than or equal to some given constant bound. Tools for searching for similar structures in biomolecular 3-D structure databases are becoming increasingly important in the structural biology of the post-genomic era.</p> <p>Results</p> <p>We consider an important, fundamental problem of reporting all substructures in a 3-D structure database of chain molecules (such as proteins) which are similar to a given query 3-D structure, with consideration of indels (<it>i.e.</it>, insertions and deletions). This problem has been believed to be very difficult but its exact computational complexity has not been known. In this paper, we first prove that the problem in unbounded dimensions is NP-hard. We then propose a new algorithm that dramatically improves the average-case time complexity of the problem in 3-D in case the number of indels <it>k </it>is bounded by a constant. Our algorithm solves the above problem for a query of size <it>m </it>and a database of size <it>N </it>in average-case <it>O</it>(<it>N</it>) time, whereas the time complexity of the previously best algorithm was <it>O</it>(<it>Nm</it>^<it>k</it>+1).</p> <p>Conclusions</p> <p>Our results show that although the problem of searching for similar structures in a database based on the RMSD measure with indels is NP-hard in the case of unbounded dimensions, it can be solved in 3-D by a simple average-case linear time algorithm when the number of indels is bounded by a constant.</p

Using least median of squares for structural superposition of flexible proteins

<p>Abstract</p> <p>Background</p> <p>The conventional superposition methods use an ordinary least squares (LS) fit for structural comparison of two different conformations of the same protein. The main problem of the LS fit that it is sensitive to outliers, i.e. large displacements of the original structures superimposed.</p> <p>Results</p> <p>To overcome this problem, we present a new algorithm to overlap two protein conformations by their atomic coordinates using a robust statistics technique: least median of squares (LMS). In order to effectively approximate the LMS optimization, the forward search technique is utilized. Our algorithm can automatically detect and superimpose the rigid core regions of two conformations with small or large displacements. In contrast, most existing superposition techniques strongly depend on the initial LS estimating for the entire atom sets of proteins. They may fail on structural superposition of two conformations with large displacements. The presented LMS fit can be considered as an alternative and complementary tool for structural superposition.</p> <p>Conclusion</p> <p>The proposed algorithm is robust and does not require any prior knowledge of the flexible regions. Furthermore, we show that the LMS fit can be extended to multiple level superposition between two conformations with several rigid domains. Our fit tool has produced successful superpositions when applied to proteins for which two conformations are known. The binary executable program for Windows platform, tested examples, and database are available from <url>https://engineering.purdue.edu/PRECISE/LMSfit</url>.</p

Ice Initiation by Aerosol Particles: Measured and Predicted Ice Nuclei Concentrations versus Measured Ice Crystal Concentrations in an Orographic Wave Cloud

The initiation of ice in an isolated orographic wave cloud was compared with expectations based on ice nucleating aerosol concentrations and with predictions from new ice nucleation parameterizations applied in a cloud parcel model. Measurements of ice crystal number concentrations were found to be in good agreement both with measured number concentrations of ice nuclei feeding the clouds and with ice nuclei number concentrations determined from the residual nuclei of cloud particles collected by a counterflow virtual impactor. Using lognormal distributions fitted to measured aerosol size distributions and measured aerosol chemical compositions, ice nuclei and ice crystal concentrations in the wave cloud were reasonably well predicted in a 1D parcel model framework. Two different empirical parameterizations were used in the parcel model: a parameterization based on aerosol chemical type and surface area and a parameterization that links ice nuclei number concentrations to the number concentrations of particles with diameters larger than 0.5 μm. This study shows that aerosol size distribution and composition measurements can be used to constrain ice initiation by primary nucleation in models. The data and model results also suggest the likelihood that the dust particle mode of the aerosol size distribution controls the number concentrations of the heterogeneous ice nuclei, at least for the lower temperatures examined in this case