The pulsed gradient spin-echo nuclear magnetic resonance experiment is a powerful tool for studying the constitution and structure of complex systems (e.g., polydisperse systems and porous media). In applications to polydisperse systems, it is important to consider the effects of obstruction, exchange, entanglement, and diffusional averaging processes whereas in applications to porous samples, reliable structural information can only be extracted from the time-dependence of the apparent diffusion coefficient when the deleterious effects of spatially and/or temporally inhomogeneous background (magnetic field) gradients can be suppressed. These issues are considered in this review.

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Spatial and temporal patterns of urban vegetation have been widely studied since the mid-twentieth century, but these studies have focused mainly on northern hemisphere countries, and little research has been conducted in developing countries. Urban vegetation is characterized by the presence of species that are adapted to the particular environmental conditions of cities, and a high diversity of exotic species. This occurs due to a combination of factors: on one hand, it is possible to find wild vegetation (weeds) on abandoned lands or those with little intervention, as well as on walls and buildings. On the other hand, there is also an enormous variety of ornamental and mainly exotic species, which have been cultivated by humans. The processes of species selection performed individually or collectively are a major determinant of the diversity of urban vegetation and flora. Individual decisions relate to private spaces such as residential gardens whose owners manage the vegetation according to their preferences and interests. Collective decisions relate to public spaces, which, by their nature, are subject to the action of multiple stakeholders. At the collective level, decision-making occurs in the context of processes involving local governments, other state agencies, NGOs and various interest groups present in the city. Each of these actors has its own vision on the role of urban vegetation, their preferences and criteria for the selection and management. This study aims to investigate the processes of decision-making responsible for the current composition of the vegetation in public spaces of the Metropolitan Area of Santiago (MAS). Through this research is expected to identify the criteria for the selection of species to be planted in public spaces, the reasons that explain the predominance of certain species, and the difference between parks managed by different public agencies in MAS. The research assumes that the various public and private actors involved in the planting and management of vegetation in public spaces, act guided by criteria and preferences that are finally expressed in the observed patterns of urban vegetation. For this purpose, the conceptual framework of governance is used, understood as the process of decision-making concerning public affairs, which involves multiple agents or interests including government agencies, non-governmental organizations and civil society groups. The overarching objectives of this Thesis are: a) To contribute to the knowledge of interactions between governance system and urban vegetation patterns in metropolitan areas of developing countries, recognizing both social and environmental processes interacting. b) Contribute to urban planning and policies by generating knowledge relevant to decision- making regarding urban vegetation. A robust knowledge of the factors defining the composition and structure of urban vegetation is essential to design effective policies for increasing vegetation cover, with consequent environmental and social benefits.

We present the first results of the magnetic field dependence of the longitudinal nuclear magnetic relaxation of anion-cation pair of ionic liquids (Li+-ionogels) confined within a silica-like mesoporous matrices designed for lithium batteries. These results are in favour of a very-correlated dynamical motion of the anion-cation pair within the solid and disordered silica matrix.

Oil and water fractions have been identified in fluid saturated carbonate rock cores using a novel T2-T1-d pulse sequence. The inclusion of the chemical shift dimension d allows T2-T1 plots to be generated independently for the oil and water. The T2-T1-d pulse sequence utilises a “double-shot” T1 measurement that provides free induction decays (FIDs) as a function of both relaxation times for suitably broad line samples. The T2-T1-d data set is acquired in the same experimental time as a conventional T1-T2 measurement (without chemical resolution) of equivalent data density. Here we demonstrate that different behaviour can be observed between the oil and water fractions in water wet and preferentially oil wet cores, and that saturation states can be determined. This technique could provide a quantitative NMR measure of wettability.

In this thesis upward spectral radiances are analyzed, which were sampled above subtropical trade wind cumuli near Barbados. Data were collected by a new measurement setup consisting of two payloads attached to a helicopter. This unique approach allows for collocated measurements of high–resolution microphysical cloud data, aerosol particle number size dis- tributions and the radiation reflected from cloud top, yielding a quantification of the first indirect aerosol effect of shallow water clouds. With the help of the spectral radiation data methods are introduced which help to identify cloud data that are influenced by the albedo of the water surface, as well as three–dimensional radiative effects. A statistical measure of cloud inhomogeneity is introduced, characterizing the observed trade wind cumuli to exhibit medium to high inhomogeneity with respect to upward radiances in the visible wavelength range. The influence of the substantial cloud inhomogeneity on the remote sensing of the cloud optical thickness and the effective droplet radius is quantified. It is shown, that misrep- resentation of the often observed overlying thin cirrus layers in the usual retrieval approaches yields an overestimation in retrieved effective droplet radius of up to 50% and and underestimation in retrieved cloud optical thickness of up to 6%. A new retrieval algorithm is introduced which minimizes the effects of the overlying cirrus without a priori knowledge of its properties. The results from the new algorithm are compared to in situ observations of the effective droplet radius, yielding a high agreement of ±1 μm. Relative susceptibilities of the retrieved microphysical and optical cloud parameters, as well as cloud top reflectivities, are derived to quantify the first indirect aerosol effect for subtropical trade wind cumuli. These relative susceptibilities are in the range of the maximum possible susceptibility following the theory for homogeneous clouds. Parameterizations of the cloud optical thickness and the effective droplet radius as a function of the derived relative susceptibilities and the liquid water path are introduced. The parameterized and measured parameters agreee with a correlation coefficient of 0.97, showing that the parameterization can reliably represent the measurements.

Die entsprechend der Quellstärke größte Fraktion des atmosphärischen Aerosols ist der natürliche Grobstaub (Seesalz, Mineralstaub und primär biologische Partikel). Nahezu alle natürlichen Grobstaubpartikel in trockener Phase weisen mehr oder weniger starke Abweichungen von der sphärischen Form auf. Der Einfluss der Asphärizität auf die aerodynamischen und optischen Eigenschaften kann durch sogenannte Formfaktoren unter Verwendung einer Referenzgröße berücksichtigt werden. Für wissenschaftliche Fragestellungen, die sowohl auf aerodynamischen wie auch optischen Aspekten beruhen, bedarf es einer vollständigen Betrachtung des Einflusses der Partikelmorphologie, um ein physikalisch plausibles Ergebnis zu erhalten. Gegenstand dieser Arbeit ist die Analyse der Relationen zwischen aerodynamischen und optischen Eigenschaften. Ziel ist die approximative Darstellung der optischen Formfaktoren durch den aerodynamischen Formfaktor als Maßzahl der Asphärizität. Hierfür wurden sowohl geometrische Formparameter als auch aerodynamische und optische Formfaktoren für ein Ensemble von regelmäßigen und unregelmäßigen Partikeln simuliert. Der Approximation der optischen Formfaktoren durch den aerodynamischen Formfaktor werden theoretische Überlegungen und Ergebnisse numerischer Simulationen vorangestellt. Die optischen Formfaktoren sind dabei primär eine Funktion des Größenparameters (Partikelgröße und Wellenlänge) und des aerodynamischen Formfaktors. In Laborexperimenten wurden beide Abhängigkeiten unter Verwendung von Proben mit Partikeln unterschiedlicher Asphärizität validiert. Die resultierende Approximation ermöglicht eine einfache und konsistente Beschreibung des Einflusses der Partikelmorphologie auf die aerodynamischen und optischen Eigenschaften. Dies ist eine unabdingbare Voraussetzung für eine genauere Analyse von Partikeleigenschaften, die aus aerodynamisch und optisch basierten In-situ-Messungen abgeleitet werden.