The summer flood of 2013 set a new record for large-scale floods in Germany for at least the last 60 years. In this paper we analyse the key hydro-meteorological factors using extreme value ...statistics as well as aggregated severity indices. For the long-term classification of the recent flood we draw comparisons to a set of past large-scale flood events in Germany, notably the high-impact summer floods from August 2002 and July 1954. Our analysis shows that the combination of extreme initial wetness at the national scale - caused by a pronounced precipitation anomaly in the month of May 2013 - and strong, but not extraordinary event precipitation were the key drivers for this exceptional flood event. This provides additional insights into the importance of catchment wetness for high return period floods on a large scale. The database compiled and the methodological developments provide a consistent framework for the rapid evaluation of future floods.
•PN emissions of Euro 6 gasoline and CNG vehicles in the size ranges 10nm and higher.•Comparisons at different sampling locations.•Analysis of particle emission in different operating conditions ...including cold start.•Comparisons among DI and MPI injection systems in terms of particle emissions.•Correlation of the particle emissions to the rated power displacement ratio of the engines.
Current particle number (PN) emission limits set by regulation, involve counted particles with a dimension >23 nm. The measurement procedure is specified and involves the dilution of the exhaust gas in a so-called constant volume sampling (CVS) device. Research efforts are concentrating in the further development of existing measurement techniques in order to capture smaller particles down to 10 nm, given their higher health threatening potential.
In the present study, six state of art, Euro 6, gasoline vehicles and in addition, one compressed natural gas (CNG) light duty vehicle, have been measured on the chassis dynamometer during different test cycles. Three particle sampling lines have been used, two in parallel at the CVS, counting particles >23 nm and 10 nm, and a third one directly at the tailpipe of the vehicle. The results allow a detailed evaluation of the emitted PNs. In addition, differences in the emissions patterns of the direct fuel injection (DI) and multi point port injection (MPI) gasoline vehicles could be identified. During cold starts, particles have been separated in distinctive size classes in order to obtain relevant number-size distributions.
Counting particles >10 nm resulted in roughly doubling the PN emissions in respect to those when counting particles >23 nm. This relation holds for all examined driving cycles. PNs measured at the CVS where significantly higher than at the tailpipe, especially when capturing also the smaller particles. The CVS could be identified contributing to the increase of the registered particle numbers during cycle parts with no or very low engine particle emissions.
Lowest PN emissions have been measured in combination with the CNG vehicle. The differences between DI and MPI gasoline vehicles have been significantly lower than expected from previous studies. While the MPI gasoline vehicles have been identified to emit more PN during cold start, the DI vehicles emit larger numbers during high engine loads. During cold starts, higher emissions of smallest particles have been evident.
The increased rated power to displacement ratio of modern engines, based on the current “downsizing” trend, shows a good correlation with the PN emissions.
A recent article by Shi et al. J. Chem. Phys.123, 174507 (2005) reports results from mechanical measurements on three simple inorganic glass formers: glycerol, m-toluidine, and sucrose benzoate. The ...experiments carried out were stress relaxation, aging, and dynamic (all in shear) using a torsional rheometer, an advanced rheometric expansion system (TA Instruments). The original force rebalance transducer (2KFRT) supplied with the system was replaced with a custom-made load cell (Sensotec) that had a capacity of 20 000 g cm in torque and 5000 g in normal force. The replacement of the load cell was done due to the belief that the main source of compliance in this instrument was from the 2KFRT. With this assumption, the authors published their results for the three materials of interest and compared their results with the techniques of Schroter and Donth J. Chem. Phys.113, 9101 (2000) for the measurements on glycerol and reported important differences. These differences were disputed by one of the present authors (Schroter), and the present report shows that the results from Schroter and Donth are correct. We show that the reasons have to do with the instrument compliance being greater than originally thought by Shi et al. Here we examine the effects of platen diameter/geometry on the glycerol dynamic moduli, describe a means to correct dynamic data, present a revised comparison of the corrected data with that of Schroter and Donth, and provide a discussion of future work and conclusions.
The determination of the temperature fluctuation in a representative subsystem from experimental calorimetric curves is discussed. Contrary to the traditional fluctuation approach it is suggested to ...use the dispersion width of the corresponding relaxation spectrum and not the width of the peak in the imaginary part of the complex heat capacity as a measure of the temperature fluctuation in local subsystems. This leads to larger estimates for the length scales of the dynamic heterogeneity of the dynamic glass transition than originally supposed. A correction method for former results is given and the comparison with other experimental results is discussed.
A highly efficient one-step process to generate Cu-Zn colloids was developed, in which the colloidal particles were synthesized from Cu and Zn stearates by reduction with H(2) in a continuously ...operated stirred tank reactor. The resulting spherical, well separated particles have a size of 5-10 nm, consisting of a crystalline Cu(0) core (fcc) stabilized by a Zn stearate shell without long-range order. In situ attenuated total reflection FTIR spectroscopy was used to monitor the shift of the C-O stretching vibration of adsorbed CO as a function of temperature and pressure. The absence of the CO rotation-vibration bands of dissolved CO allowed us to obtain FTIR spectra at a CO pressure of 1.0 MPa at 473 K resulting in three shifted CO bands at 2030-2025, 1979-1978, and 1920 cm(-1). These bands indicate the presence of reduced coadsorbed Zn species on the metallic Cu surface. Cyclic CO adsorption experiments demonstrated the dynamics of the interaction between the Cu core and the Zn stearate shell.
Shear data in the temperature range from −145 °C to the flow zone are presented for the poly(n-alkyl methacrylate)s from methyl (C = 1) to lauryl (C = 12). Three qualitatively different glass ...transitions are observed in the shear curves at 10 rad/s: (i) the conventional α process in the C < 5 members, (ii) the high temperature a process in the C > 5 members, and (iii) an additional polyethylene-like glass transition, αPE, in the C ≥ 3 members. All three processes depend systematically on side chain length. Two alternative empirical pictures for the coexistence of two glass transitions are discussed: (a) a static nanophase separation between main chains and side chains and (b) a dynamic heterogeneity with two different time and length scales.
The dynamic shear response of six glass formers (the epoxy resin diglycidyl ether of bisphenol-A, propylene carbonate, glycerol, two bulk metallic glasses, and a soda lime glass) from different ...substance classes with widely differing fragility is compared: No correlation of the shear Kohlrausch exponent with fragility was observed. A comparison of shear with multidimensional NMR results on glycerol is compatible with dynamic heterogeneity in glass formers having mobile islands in a lesser mobile matrix.
At the end of October 2012, Hurricane Sandy moved from the Caribbean Sea into the Atlantic Ocean and entered the United States not far from New York. Along its track, Sandy caused more than 200 ...fatalities and severe losses in Jamaica, The Bahamas, Haiti, Cuba, and the US. This paper demonstrates the capability and potential for near-real-time analysis of catastrophes. It is shown that the impact of Sandy was driven by the superposition of different extremes (high wind speeds, storm surge, heavy precipitation) and by cascading effects. In particular the interaction between Sandy and an extra-tropical weather system created a huge storm that affected large areas in the US. It is examined how Sandy compares to historic hurricane events, both from a hydro-meteorological and impact perspective. The distribution of losses to different sectors of the economy is calculated with simple input-output models as well as government estimates. Direct economic losses are estimated about USD 4.2 billion in the Caribbean and between USD 78 and 97 billion in the US. Indirect economic losses from power outages is estimated in the order of USD 16.3 billion. Modelling sector-specific dependencies quantifies total business interruption losses between USD 10.8 and 15.5 billion. Thus, seven years after the record impact of Hurricane Katrina in 2005, Hurricane Sandy is the second costliest hurricane in the history of the United States.
Flood loss models are one important source of uncertainty in flood risk assessments. Many countries experience sparseness or absence of comprehensive high-quality flood loss data, which is often ...rooted in a lack of protocols and reference procedures for compiling loss datasets after flood events. Such data are an important reference for developing and validating flood loss models. We consider the Secchia River flood event of January 2014, when a sudden levee breach caused the inundation of nearly 52 km.sup.2 in northern Italy. After this event local authorities collected a comprehensive flood loss dataset of affected private households including building footprints and structures and damages to buildings and contents. The dataset was enriched with further information compiled by us, including economic building values, maximum water depths, velocities and flood durations for each building. By analyzing this dataset we tackle the problem of flood damage estimation in Emilia-Romagna (Italy) by identifying empirical uni- and multivariable loss models for residential buildings and contents. The accuracy of the proposed models is compared with that of several flood damage models reported in the literature, providing additional insights into the transferability of the models among different contexts. Our results show that (1) even simple univariable damage models based on local data are significantly more accurate than literature models derived for different contexts; (2) multivariable models that consider several explanatory variables outperform univariable models, which use only water depth. However, multivariable models can only be effectively developed and applied if sufficient and detailed information is available.
The development of the dynamic glass transition in poly(n-alkyl methacrylate)s is investigated with broad-band dielectric spectroscopy in the frequency range from 10-4 to 109 Hz. The experimental ...data were analyzed by adjustment with one or a sum of two Havriliak Negami functions. Upon decreasing the temperature, the high-temperature relaxation (a) changes into the local β relaxation (Johari Goldstein mode), and the cooperative α relaxation sets in close to this aβ transition. For poly(n-butyl methacrylate) a separate onset (zero intensity) of the α process and a parallel course of both traces in the Arrhenius diagram were observed. The activation energy of the β process does not change in spite of the parallel development of the α process. On the other hand, for poly(ethyl methacrylate) the α onset is close to a bend in the local process, i.e., the activation energy of the latter changes after the α onset. In both materials the intensity of the α process linearly increases with falling temperatures but with different intensity. Several scenarios for the αβ-splitting region are suggested.
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