Analysis of the Double-Bounce Interaction between a Random Volume and an Underlying Ground, Using a Controlled High-Resolution PolTomoSAR Experiment

The radar response of vegetated environments, and forested areas in particular, are usually modeled using a very simple structure made of a random volume, representing a cloud of vegetation particles, lying over a semi-infinite medium with a rough interface, associated with the underlying ground. This Random Volume over Ground model can efficiently handle double-bounce scattering mechanisms, or arbitrary volume reflectivity profiles. This paper proposes to analyze a specific component of the Random Volume over Ground simplified scattering model, which concerns the double-bounce interaction between the ground and the volume. This specific contribution is not considered by classical characterization techniques and is studied in this work using a controlled experiment involving a Synthetic Aperture Radar operated in a Polarimetric and Tomographic configuration in order to image in 3D a controlled miniaturized scene composed of volume lying over a ground. It is shown that ground/volume double-bounce scattering, which remains focused at the ground level even in 3D imaging mode, and has polarimetric patterns that differ largely from those usually expected from double-bounce reflections, with volume-like features, such as a strong cross-polarized reflectivity or decorrelation between co-polarized channels. Moreover, it is shown that the full rank polarimetric patterns of the ground-volume mechanism are tightly linked to the reflectivity of the volume and may mask the ground response. As a consequence, isolating the ground response using 3D imaging does not permit to avoid a generally very strong distortion of the soil response by the double-bounce reflection, and the estimation of different geophysical parameters of the ground, such as its humidity or roughness are significantly altered.

Growth of Homogeneous Luminescent Silicon–Terbium Nanowires by One-Step Electrodeposition in Ionic Liquids

An electrodeposition method for the growth of homogeneous silicon–terbium nanowires (NWs) with green light emission is described. The method involves template-assisted electrochemical co-deposition of Si/Tb NWs with 90-nm diameter from an electrolyte bath containing Si and Tb precursors in an ionic liquid (IL). This method of deposition is advantageous over other conventional techniques as it is relatively simple and cost-effective and avoids harsh deposition conditions. The deposited NWs are of uniform dimensions with homogeneous composition incorporating 10% of Tb and exhibit intense room temperature (RT) luminescence in the visible range due to Tb emission. These results were confirmed by combining classical characterization such as scanning electron microscopy (SEM) and photoluminescence (PL) performed on an assembly of NWs with spatially resolved experiments such as transmission electron microscopy (TEM) and cathodoluminescence (CL). This electrodeposition method provides an alternative and extremely simple approach for depositing silicon-rare earth nanostructures for optical and sensing applications.

Purity and approximation with respect to a class of morphisms

We investigate purity and approximation with respect to a class of morphisms of modules. Let [Formula: see text] be a class of left [Formula: see text]-module morphisms. An epimorphism [Formula: see text] of left [Formula: see text]-modules is called [Formula: see text]-pure if for any morphism [Formula: see text] in [Formula: see text], there is a morphism [Formula: see text] such that [Formula: see text]. An [Formula: see text]-pure epimorphism [Formula: see text] is called [Formula: see text]-superfluous if every morphism [Formula: see text] with [Formula: see text] [Formula: see text]-pure is itself [Formula: see text]-pure. We get many properties of [Formula: see text]-pure and [Formula: see text]-superfluous morphisms. As an application, we generalize the classical characterization of a projective cover to a general setting of an [Formula: see text]-cover. It is proven that an epimorphism [Formula: see text] in [Formula: see text] is an [Formula: see text]-cover of [Formula: see text] if and only if [Formula: see text] has an [Formula: see text]-cover and [Formula: see text] is an [Formula: see text]-superfluous epimorphism if and only if [Formula: see text] is [Formula: see text]-pure and there is no proper submodule [Formula: see text] of [Formula: see text] such that [Formula: see text] and [Formula: see text] is [Formula: see text]-pure. In addition, some dual results are also given.

Descriptors for High Throughput in Structural Materials Development

The development of novel structural materials with increasing mechanical requirements is a very resource-intense process if conventional methods are used. While there are high-throughput methods for the development of functional materials, this is not the case for structural materials. Their mechanical properties are determined by their microstructure, so that increased sample volumes are needed. Furthermore, new short-time characterization techniques are required for individual samples which do not necessarily measure the desired material properties, but descriptors which can later be mapped on material properties. While universal micro-hardness testing is being commonly used, it is limited in its capability to measure sample volumes which contain a characteristic microstructure. We propose to use alternative and fast deformation techniques for spherical micro-samples in combination with classical characterization techniques such as XRD, DSC or micro magnetic methods, which deliver descriptors for the microstructural state.

Harmonic light scattering study reveals structured clusters upon the supramolecular aggregation of regioregular poly(3-alkylthiophene)

Solubilized poly(3-alkylthiophene)s are known to self-assemble into well-ordered supramolecular aggregates upon lowering the solvent quality. This supramolecular organization largely determines the optical and electronic properties of these polymers. However, despite numerous studies the exact mechanism and kinetics of the aggregation process and the role of external stimuli are still poorly understood. Classical characterization techniques such as electronic spectroscopy, dynamic light scattering, and diffraction-based techniques have not been able to provide a full understanding. Here we use second-harmonic scattering (SHS) and third-harmonic scattering (THS) techniques to investigate this supramolecular aggregation mechanism. Our results indicate that the actual supramolecular aggregation is preceded by the formation of structured polymer-solvent clusters consistent with a nonclassical crystallization pathway.

Structural Architectural Features of Cyclodextrin Oligoesters Revealed by Fragmentation Mass Spectrometry Analysis

Cyclodextrins (CDs) were used in the present study for the ring-opening oligomerization (ROO) of l-lactide (LA) in order to synthesize biodegradable products with possible applications in pharmaceutical and medical fields. The practical importance of ROO reactions may reside in the possibility of synthesizing novel CD derivatives with high purity due to the dual role played by CDs, the role of the initiator through the hydroxylic groups, and the role of the catalyst by monomer inclusion in the CD cavity. The analyzed compounds were CDs modified with oligolactides obtained through ROO reactions of l-lactide in dimethylformamide. The resulting CD isomeric mixtures were investigated using classical characterization techniques such as gel permeation chromatography and nuclear magnetic resonance. Moreover, advanced mass spectrometry (MS) techniques were employed for the determination of the average number of monomer units attached to the cyclodextrin and the architecture of the derivatives (if the monomer units were attached as a single chain or as multiple chains). Thus, fragmentation studies effectuated on two different instruments (ESI Q-TOF and MALDI TOF) allowed us to correlate the size of the oligolactide chains attached to the CD with the observed fragmentation patterns.

A study to assess awareness on disaster management among school going children in Gwalior (M.P.)

Background: The classical characterization of disaster is unfamiliarity, unpredictability, uncertainty, vulnerability, urgency, intensity and danger. Major disasters include earthquake, landslides, volcanic eruptions, floods hurricanes, fires, tornados, blizzards, tsunamis, cyclones. Apart from causing deaths and severe ill health, disasters also lead to large scale displacement, injuries, epidemics and substantial economic losses to the communities. Though every emergency or disaster has it’s own characteristics and demands but the basic measures under disaster management include prevention, mitigation, preparedness, response and recovery for which regular training and awareness activities are needed especially among students. The objective of the study was to assess the extent of awareness about disasters and their management among school going children.Methods: It was an educational interventional design with an exploratory research approach adopting non- probability purposive sampling technique. Kendriya vidhyalaya no: 4 affiliated to CBSE was randomly selected, which is situated in mid of the Gwalior town. Survey method was employed, on 110 participants aged between 12 and 16 years using a pre-tested semi structured questionnaire data sheet.Results: The outcome revealed that out of 110 students 87.2% (before intervention) and 98.2% (after intervention) had knowledge of disaster management.Conclusions: These findings emphasize that the extent of knowledge is not yet satisfactory and there is a severe need of providing knowledge to the school children. Disaster management can be compulsorily included in academic curriculum of all the students. Effective, purposeful training and awareness programmes are to be timely conducted.