Search results for "MATTER"
showing 10 items of 16762 documents
Synthesis and solid state structure for a series of poly(1-pyrrolylmethyl)benzene derivatives. Control of the interplaying π–π and C–H⋯π interactions?
2006
The syntheses of new hexa- and 1,2,4,5-tetra-1-pyrrolylmethyl-benzene (1 and 2, respectively) compounds and their crystal structures, along with those for the related disubstituted o-, m- and p-di-1-pyrrolylmethyl-benzene (3–5) derivatives are reported. The arrangements of molecules in the 1-D structure for 2–5 are controlled by the interplay of two different weak interactions: π–π and C–H⋯π (Ph) interactions. The absence of such interactions in the packing of 1 seems to be related to the arrangement of the pyrrolylmethyl arms with respect to the benzene core, which prevents the π cloud of the aromatic ring to be part of any intermolecular interaction. In addition, C–H⋯π (pyrrolyl) interact…
Extending the halogen-bonded supramolecular synthon concept to 1,3,4-oxadiazole derivatives
2016
A series of five crystal structures of 1:1 halogen-bonded complexes were obtained from 4-[5-(4-alkoxyphenyl)-1,3,4-oxadiazole-2-yl]pyridine and 1,3,5-trifluorotriiodobenzene. Electronic structure calculations show that the N(oxadiazole)⋯I interaction in the new synthon is as strong as the classic N(pyridine)⋯I interaction. Oxygen to sulfur atom subsitution on the oxadiazole ring results in a different supramolecular packing where the N(pyridine)⋯I interaction is favored, which could be rationalized by the changes in the molecular electrostatic potential predicted from the theoretical calculations.
Quasi-geostrophic jet-like flow with obstructions
2021
International audience; Jet-like flows are ubiquitous in the atmosphere and oceans, and thus a thorough investigation of their behaviour in rotating systems is fundamental. Nevertheless, how they are affected by vegetation or, generally speaking, by obstructions is a crucial aspect which has been poorly investigated up to now. The aim of the present paper is to propose an analytical model developed for jet-like flows in the presence of both obstructions and the Coriolis force. In this investigation the jet-like flow is assumed homogeneous, turbulent and quasi-geostrophic, and with the same density as the surrounding fluid. Laws of momentum deficit, length scales, velocity scales and jet cen…
Influence of Wind on Suspended Matter in the Water of the Albufera of Valencia (Spain)
2021
Wind is one of the factors that has a great influence on suspended matter in lakes, especially in shallow lagoons. In order to know how wind affects the water in Albufera of Valencia, a shallow coastal lagoon, the measured variables of turbidity and transparency have been correlated with the estimates by processing Sentinel-2 satellite images with the Sen2Cor processor. Data from four years of study show that most of them are light to gentle easterly breezes and moderate to fresh westerly breezes. The results obtained show significant correlations between the measured variables and those obtained from the satellite images for total suspended matter and water transparency and with the averag…
Associations between air pollution and pediatric eczema, rhinoconjunctivitis and asthma: A meta-analysis of European birth cohorts
2020
Background: Uncertainly continues to exist regarding the role of air pollution on pediatric asthma and allergic conditions, especially as air pollution levels have started to decrease in recent decades. Objective: We examined associations of long-term air pollution levels at the home address with pediatric eczema, rhinoconjunctivitis and asthma prevalences in five birth cohorts (BIB, EDEN, GASPII, RHEA and INMA) from seven areas in five European countries. Methods: Current eczema, rhinoconjunctivitis and asthma were assessed in children aged four (N = 6527) and eight years (N = 2489). A multi-morbidity outcome (≥2 conditions versus none) was also defined. Individual outdoor levels of nitrog…
High-resolution stimulated Raman spectroscopy and analysis of the nu2, nu5 and 2 nu6 bands of 34SF6
2006
9 p.Special Issue: Nineteenth Colloquium on High Resolution Molecular Spectroscopy, Salamanca 11–16 September 2005
Effects of natural radiation damage on back-scattered electron images of single crystals of minerals
2006
Generally, it has been assumed that signal intensity variations in back-scattered electron (BSE) images of minerals are mainly controlled by chemical heterogeneity. This is especially true for images of single crystals, where effects of different crystal orientations with respect to the incident beam on the observed BSE are excluded. In contrast, we show that local variations of the structural state within single-crystals (i.e., degree of lattice order or lattice imperfectness) may also have dramatic effects on the back-scattering of electrons. As an example, we present BSE images of single-crystals of natural zircon, ZrSiO 4 , whose intensity patterns are predominantly controlled by struct…
Soil organic carbon stock on the Majorca Island: temporal change in agricultural soil over the last 10 years
2019
8 Pags.- 5 Tabls.- 3 Figs.
The effect of rheological approximations in 3-D numerical simulations of subduction and collision
2018
Abstract Subduction and collision zones evolve differently from one another due to different rheological properties, different amounts of regional isostatic compensation, and the different mechanisms by which forces are applied to the convergent plates. The rheology of mantle and lithosphere is known to have the largest influence on the dynamics of subduction and continental collision. However, previous 3-D geodynamic models of subduction/collision processes have used various rheological approximations, making their results difficult to compare, since there is no clear understanding on the extent of these approximations on the dynamics. Here, we test the effect of rheological approximations…
Relations between Air Quality and Covid-19 Lockdown Measures in Valencia, Spain
2021
The set of measures to contain the diffusion of COVID-19 instituted by the European governments gave an unparalleled opportunity to improve our understanding of the transport and industrial sectors’ contribution to urban air pollution. The purpose of this study was to assess the impacts of the lockdown measures on air quality and pollutant emissions in Valencia, Spain. For this reason, we determined if there was a significant difference in the concentration levels of different particulate matter (PM) sizes, PM10, PM2.5, and NOx, NO2, NO, and O3, between the period of restrictions in 2020 and the same period in 2019. Our findings indicated that PM pollutant levels during the lockdown period…