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In this work, pectin extracts from watermelon rind (WRP) were enzymatically treated to evaluate their potential for preparing hydrogels with the addition of CaCl2. Based on a previous work, two different conditions were selected to obtain WRP extracts according to the 1) highest yield (OP) or 2) highest yield without negatively affecting the branching and native structure of pectin (OPA). Firstly, both WRP extracts were enzymatically modified using different treatments (de-esterification and/or de-branching of galacturonic and arabinose side chains, and deproteinization), and their impact on the esterification degree, monosaccharide composition and changes on their structural properties (linearity and branching degree) were analysed. Then, the effect of the structural properties of the resulting pectin on the rheological behaviour and nanostructure of the hydrogels was investigated. The presence of long branched side chains and high methyl-esterified galacturonic acid chains promoted the formation of weaker hydrogels whereas de-esterification of the original pectin enabled intermolecular association giving rise to stronger hydrogels with the formation of ordered and densely packed structures (as deduced from SAXS results). However, the presence of small arabinogalactans side chains in the de-branched and de-esterified pectin extracts acted as reinforcement agents, inducing the formation of more densely packed networks and stronger hydrogels than their less-branched counterpart. These results demonstrated the impact of the pectin structure on the hydrogel-forming capacity., Grant RTI-2018-094268-B-C22 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”. This work was also funded by the grant INNVAL10-19-009 - CA8250 from Agència Valenciana d'Innovació (AVI). D.A. Méndez. is supported by the Administrative Department of Science, Technology and Innovation (Colciencias) of the Colombian Government (783–2017). This research is part of the CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094. Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy+. (PTI-SusPlast+) is also acknowledged for financial support.

Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso-2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues., This work was supported by Conicet PIP 0897 and 567, UNLP x807 and UBACYT 20020130100673A and we kindly thank Brazilian Synchrotron Light Laboratory (Proposals: SAXS1-14429, SAXS2-22014, SAXS1-20160237, Campinas-Brazil, Universidad Nacional de La Plata-Argentina, and CONICET-Argentina. We thanks Maria del Puerto Morales for usefull discussion. The group of IFLP thanks Instituto de Investigaciones Bioquímicas de La Plata INIBIOLP Patología B - CONICET for allowing the use of cell culture lab, help in cell culture handling and kind suggestions on biological issues and Y-TEC S. A. for the use of TEM TALOS F200X under the supervision of A. Floridia and A. Caneiro. M. E. F. Brollo acknowledges the Brazilian agency CNPq for the grant [232947/2014-7] within the Science without Borders program A.R acknowledges financial support from the Spanish Ministry of Science and Innovation through the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (CEX2019-000917-S). M. B. Fernández van Raap, P. C. Setton-Avruj and P. Mendoza Zélis, are members of CONICET, and P. A. Soto is a fellow of CONICET, Argentina., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).

This overview introduces nuclear resonant scattering techniques with synchrotron radiation. After a focus on nuclear resonant scattering in general, two popular methods with a wide range of applications, nuclear resonant inelastic X-ray scattering and synchrotron Mossbauer spectroscopy are described in greater detail. The inelastic method provides specific vibrational information such as the phonon density of states. The Mossbauer method permits determination of hyperfine interactions. Nuclear resonant techniques take full advantage of the unique properties of synchrotron radiation: intensity, collimation, time structure, and polarization. As a result both methods discussed here have led to novel applications for materials under extreme conditions, proteins with biological functionality, and magnetic nanostructures.

Thermoelectric materials are capable of directly converting heat into electricity by the Seebeck effect, which are applicable to a wide range of industrial applications. For semiconductor thermoelectrics, one of the most effective ways to enhance their performance is to use nanostructures to significantly reduce their lattice thermal conductivity, which is governed by lattice vibrations referred to as phonons, without dramatically sacrificing their electrical properties. Hence, the transport of phonons in nanostructured thermoelectrics is of crucial importance. This chapter stresses the basic concepts and fundamental principles of the transport of phonons in nanostructured materials. Starting with the concepts of phonons and phonon Boltzmann transport equation, we can derive the phonon gas model for thermal conductivity. Various scattering mechanisms of phonons that affect the thermal conductivity in nanostructured materials, well-established theoretical and experimental methods used for the investigation of phonon transport, and examples in terms of manipulating phonons with nanostructures in the field of thermoelectrics are described.

In this chapter, scattering studies of nanocomposites of polyhedral oligomeric silsesquioxane (POSS) with various polymer types have been outlined. Scattering studies including dynamic light scattering (DLS), static light scattering (SLS), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), small angle neutron scattering (SANS), and powder X-ray diffraction (XRD) were discussed. Scattering studies examine the structural behavior and dynamics of composites at the nanoscale in addition to the size of nanoparticles. Nanocomposites of POSS with various polymers including polyolefins, engineering plastics, thermosetting polymers, elastomers, and biopolymers available in recent research studies were focused on in this chapter.

X-ray and neutron scattering belong to principal tools in the investigation of structure and dynamics of materials. This chapter resumes information on structural aspects important on various length scales in natural rubber and its products revealed by various methods of X-ray and neutron scattering. Principles of scattering theory and scattering functions important for the analysis of the systems based on natural rubber are reviewed. Experimental determination of key structural parameters such as degree of crystallinity, polymer network mesh size, correlation lengths, fractal dimensions, and so on is also discussed. Results obtained from natural rubber that is uncrosslinked, crosslinked or filled by various types of nanofillers are compared and reviewed.

When X-rays strike atoms in a crystal, the phenomenon of scattering takes place. When the scattered X-rays from one atomic layer are in phase with scattered X-rays from another plane, then diffraction occurs, which enhances wavefronts. Atomic layer distances can be calculated from Bragg’s law of diffraction. Diffraction patterns act as fingerprints for a material. In this way, an unknown sample can be matched with a database to find a database that helps to describe the material. Nanomaterials exhibit diffraction patterns that are much broader compared to their bulk counterparts. This broadening helps to calculate the crystallite size.

Phonons are fundamental carriers of thermal energy in crystalline solids. Microscopic heat transfer analysis rely on properties and dynamics of phonons. Phonon wave packet method is a molecular dynamics simulation to visualize the phonon dynamics and scattering to calculate the energy transmission coefficient and to study phonon conversion. In this chapter, the machinery and the practice of phonon wave packet method are discussed with applications on carbon nanostructures.

Elastic neutron and X-ray scattering provide an analytical technique to monitor the structure of polymers and other soft materials. Standard small-angle scattering instruments provide insight into structure over length scales that range from a few angstroms to 100s of nm. This chapter details the fundamental relationships between the observed scattering pattern and nanoscale structure and provides specific examples of analyses that are available to extract desired information. Comparison of the fundamental bases for scattering contrast and accessible lengths scales for X-rays and neutrons is presented to provide a foundation to choose the scattering method that provides target structural characteristics for a given system. The importance of tunable scattering contrast with deuteration in the neutron scattering of soft materials is described to emphasize the ability to extract specific structural characteristics in complex multicomponent systems. Novel sample environments that take advantage of the penetration of most materials by neutrons and rapid data capture of synchrotron sources are also described. Finally, a series of specific examples that utilize X-ray and neutron scattering to elucidate the structure, transport, and kinetics of assembly in a range of soft materials are offered.

This account highlights small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) in studies of long-chain omega-3 polyunsaturated fatty acids (PUFAs) and their delivery systems. Fundamentals of small-angle scattering are introduced. Examples representing four colloidal PUFA delivery systems are described: 1. Particle systems where PUFAs are complexed with another molecule to form well-defined nanoscale objects in aqueous phase. 2. Periodic systems where PUFAs are located within self-organized amphiphilic molecules forming lyotropic liquid crystalline phases. 3. Continuous systems where PUFAs form network-like sponge phases and other phases extended toward micrometer scale and beyond. 4. Semiinfinite two-dimensional systems where macroscopic PUFA droplets are separated from water by a thin microscopic interface. Associated structural characteristics, applicability and limits of small-angle scattering, complementarities of X-rays and neutrons as well as possibilities to connect these ideas to the oxidative stability are discussed.

This chapter deals with the structural analysis of ionic liquid-containing mixtures through multiscale computational methods. The chapter is divided into two sections, dealing with a basic introduction to the topic, and a more in-depth presentation of four different computational methods typically used to simulate the structural and dynamical properties of complex liquid systems. Initially, the concept of the structure of a liquid is discussed, providing definitions and some examples. Subsequently, the main features of the experimental technique based on X-ray scattering are presented, which allow accessing structural information of amorphous systems. A short introduction of the laws governing the scattering phenomenon, and how scattered photons can provide information about the structure of a system is also presented. A significant part of this chapter is devoted to introducing four of the most used state-of-the-art computational methods, namely density functional theory “static” optimization, semiempirical molecular dynamics, classical molecular dynamics, and coarse-grained molecular dynamics. The starting point is the quantastic treatment of the system, in which only minimal approximations are used. The reader is then guided toward successive approximations enabling to explore different system sizes and timescales. The intricate system ethylammonium nitrate:acetonitrile 1:9 binary mixture is taken as a case study to show what the four obtained models can return in terms of characterization. The final picture describes how the various methods are fundamentally complementary to each other, meaning that there is nothing as a “best” method.

Associating soft matter such as surfactants, polymers, proteins, and liposomes, may form structures with dimensions not readily accessible by optical methods. Scattering methods can provide detailed information about the mechanism of associative phase separation including nucleation density, size, and shape. Ultra-small angle neutron scattering, a reciprocal space method, provides sensitivity to submicron to micron-scale structures in a non-invasive manner and described in the context of nucleation and growth of dilute droplets formed by a temperature jump into the meta-stable region of polyelectrolyte complex coacervates.

This chapter discusses the various methods and codes used in analyzing thermal (light-water reactors) and fast reactor (sodium-cooled fast reactors) cores. Multigroup nuclear data libraries and details of lattice physics calculations to account spatial and energy self-shielding effects in the resonance analysis are discussed. The whole-core calculations for estimating steady-state neutronics parameters for plant operation are also given. In addition, a brief outline of safety analysis and severe accident analysis in fast reactors is given at the end. The aim of reactor analysis is to obtain the neutron density distribution as a function of space, energy, scattering angle, and time. The neutron balance equation is formulated in the region of interest and solved for the fluxes. The problem is divided into two main sequences. First, the reactor core is considered to be an ensemble of small units. The neutron transport is treated in a hyperfine energy structure over this unit representative cell. The spatial and energy-dependent flux is then used to homogenize the unit cell properties to derive homogenized cell cross sections called lattice parameters. This representative cell is treated either in a one-dimensional (1-D) or two-dimensional (2-D) geometry. The inputs required for the lattice-level calculations are the energy-dependent cross-section set called as nuclear physics data and the geometry of the lattice. In the next step, the whole three-dimensional (3-D) reactor core is treated as a periodic arrangement of these unit representative cells with homogenized lattice properties. The global parameters are derived from the solution of flux over the 3-D core. The criticality problem is treated as a steady-state solution by formulating a time-independent neutron balance equation. The transient solutions are obtained by introducing a time-dependence in the balance equations.

Standard scattering theory (SST) in atomic, molecular, and optical physics is incomplete in that it does not adequately describe the behavior of the wave function at macroscopic distances from the scattering reaction volume, nor does it describe the manipulation of ejected particles in fields applied after the collision or the operation of modern detectors which employ external steering fields. Here, we extend formal scattering theory by incorporating semiclassical wave function propagation to and from macroscopic distances. This theory then is applicable to modern detection methods and to the pre- and post-collision manipulation by external static fields or time-varying laser fields. Furthermore, the standard approach is time independent but the increasing use of projectiles (particles, photons) defining a time-dependent scattering potential demands an overtly time-dependent approach. Here such a time-dependent theory describing the complete experimental procedure is developed and, by consistent use of semiclassical approximations in the asymptotic zones, is connected explicitly to the well-known time-independent equations of SST. Interference of matter waves in the continuum has been studied intensively and can be considered also as a scattering problem. Our semiclassical approach allows us to make direct contact to analogous interference experiments with classical light.

6 pags., 8 figs., 3 tabs., CALIFA is the high efficiency and energy resolution calorimeter for the RB experiment at FAIR, intended for detecting high energy light charged particles and gamma rays in scattering experiments, and is being commissioned during the Phase-0 experiments at FAIR, between 2018 and 2020. It surrounds the reaction target in a segmented configuration with 2432 detection units made of long CsI(Tl) finger-shaped scintillator crystals. CALIFA has a 10 year intended operational lifetime as the RB calorimeter, necessitating measures to be taken to ensure enduring performance. In this paper we present a systematic study of two groups of 6 different detection units of the CALIFA detector after more than four years of operation. The energy resolution and light output yield are evaluated under different conditions. Tests cover the aging of the first detector units assembled and investigates recovery procedures for degraded detection units. A possible reason for the observed degradation is given, pointing to the crystal-APD coupling., This work has been financially supported by the European Union Horizon 2020 research and innovation programme under grants agree-ments No 262010 (ENSAR) and No 654002 (ENSAR2), the Spanish MICCIN grants FPA47831-C2-1P and FPA2015-69640-C2-1-P, by the Plan Galego de Investigación, Innovación e Crecemento (I2C) of Xunta de Galicia, Spain under projects POS-B/2016/015, GRC2013-011 andED431C 2017/54 and by the German BMBF (No. 05P19RDFN1), TUDarmstadt - GSI cooperation contract, HIC for FAIR.

Photonic structures allow reducing the thickness of photovoltaic (PV) devices while improving their photocurrent, thereby enabling high-efficient, low-cost, and mechanically flexible solar cells. Wave-optical front structures have shown to be promising for integration in various thin-film PV technologies, as those based on silicon or perovskite semiconductors, due to a combination of: (1) Broadband absorption amplification—wavelength-sized structures provide geometrical index-matching for the impinging light, strongly reducing reflection while boosting the photons' path length within the absorber via scattering. (2) Improved electrical performance—their incorporation in the transparent contact can enable higher electrode volume, thereby improving the cells' voltage and fill factor. Such a location can also prevent increasing the cells' roughness, therefore not contributing to recombination. (3) Enhanced stability—particularly in perovskite cells, the front photonic structures block most of the harmful UV radiation that degrades such devices. Colloidal lithography methods have revealed to be highly cost-effective for the nanopatterning of such structures, allowing compatibility with industrial scalability and low-cost requirements.

Publisher Summary This chapter focuses on spontaneous light scattering and acoustooptics. Spontaneous light scattering means light scattering under conditions such that the optical properties of the material system are unmodified by the presence of the incident light beam. Several physical processes can lead to light scattering. One of the processes is Raman scattering that results from the interaction of light with the vibrational modes of the molecules constituting the scattering medium. Raman scattering can equivalently be described as the scattering of light from optical phonons. Brillouin scattering is the scattering of light from sound waves, that is, from propagating pressure (and hence density) waves. Brillouin scattering can also be considered to be from acoustic phonons. In RayLeigh scattering or Rayleigh-center scattering, light is scattered because of nonpropagating density fluctuations. Formally, it can be described as scattering from entropy fluctuations. It is known as quasielastic scattering because it induces no frequency shift. The scattering of light from sound waves can also be applied to the situation, in which the sound wave is applied to the interaction region externally by means of a transducer. Such acoustooptic devices are useful as intensity or frequency modulators for laser beams or as beam deflectors. Acoustooptic devices are commonly classified as falling into one of two regimes; namely, Bragg scattering and Raman-Nath scattering.

The ring current decay occurs during the recovery phase of a geomagnetic storm when the particles’ injection is no longer strong enough to overcome the loss processes. The major ring current loss processes and their aeronomical effects are described in this chapter. The most important among the collisional loss processes is charge exchange, where ring current ions are neutralized on collision with thermal exospheric hydrogen atoms and produce energetic neutral atoms (ENAs) which are either lost in space or precipitate down to the atmosphere. Coulomb collisions between energetic ring current ions and coexisting low-energy plasmaspheric populations result in energy transfer from the fast moving to the thermal particles and in angular deflection of the particles. The magnetospheric energy is transported down the magnetic field lines and creates ionospheric electron and ion temperature enhancements and optical emissions known as stable auroral red (SAR) arcs. Scattering of ring current ions into the loss cone due to resonant interactions with electromagnetic ion cyclotron (EMIC) waves occurs on short timescales and leads to ion precipitation and the generation of detached proton arcs. Likewise, ring current electrons are scattered in pitch angle by whistler-mode waves and their precipitation at low altitudes affects significantly the ionospheric conductivity. In addition, particles are lost as they flow out to the dayside magnetopause or as they are moved to the loss cone by magnetospheric convection or field line curvature scattering. The ring current decay leads to the restoration of the surface magnetic field of the Earth to its prestorm values.

Dynamic nuclear polarization (DNP) can provide a powerful means to amplify neutron diffraction from biological crystals by 10-100-fold, while simultaneously enhancing the visibility of hydrogen by an order of magnitude. Polarizing the neutron beam and aligning the proton spins in a polarized sample modulates the coherent and incoherent neutron scattering cross-sections of hydrogen, in ideal cases amplifying the coherent scattering by almost an order of magnitude and suppressing the incoherent background to zero. This chapter describes current efforts to develop and apply DNP techniques for spin polarized neutron protein crystallography, highlighting concepts, experimental design, labeling strategies and recent results, as well as considering new strategies for data collection and analysis that these techniques could enable.

The area of non-resonant dielectric metamaterials comprises phenomena which occur at long wavelengths, where Mie resonances and Bragg diffraction in ordered structures do not play a role. In this spectral range effective-medium theories can be applied quite well and are therefore revisited in the first part of the chapter. Isotropic as well as anisotropic effective media are discussed and the dispersion relation for light predicted by the effective-medium theories is compared to exact photonic bandstructures in ordered metamaterials, demonstrating overall very good correspondence in the long wavelength range. After a short look at more advanced modern homogenization methods experimental techniques are discussed to determine the effective parameters. In particular measurements based on interference effects are suggested to determine group velocity, effective indices and birefringence with greater confidence. The power to control the effective refractive index and anisotropy on a local level by arranging and shaping the scattering elements in a designed way is employed to create a large variety of graded effective-index structures. These can be used to realize designs originating from transformation optics. Recent examples of graded index landscapes for metasurfaces, 2D in-plane light guiding, subwavelength structured waveguides and antireflection coatings are presented. Most of the discussed designs are based on silicon as a high index material facilitating a large range of effective refractive indices and exploiting existing nanofabrication methods. While most of the artificially created metamaterials exhibit a strict periodic order, in the last section disordered systems are discussed and possibilities of hyperuniform arrangements of scattering elements outlined.

A novel method of microwave remote sensing is to tackle the scatter theory based on the quantum concept. In this regard, this chapter explains in detail how quantum mechanics can be used to investigate the electromagnetic wave scattering theory. This chapter also describes the interaction between photons and atoms from the point of view of quantum mechanics. Consequently, nonrelativistic perturbation theory stipulates the transition amplitude for the atom-photon scattering process. This chapter explains that the scattering occurs at different quantum energies. It can be said that quantum microwave photons involve multiple scattering by atoms, which are well reformed to scrutinize broad concepts of quantum transport. Certainly, atoms are precise, effective point scatterers of light as the scattering cross-section close to an inner resonance, which is massively contrasted to the definite atomic dimension.

Small-angle and ultra-small-angle X-ray and neutron scattering techniques provide structural information on the nanometer to micron length scale. This chapter describes the fundamentals of small-angle scattering (SAS) techniques and the advantages and disadvantages over other structural characterization methods. Factors to consider in the design of SAS experiments are outlined with data collection; the chapter then proceeds to the analysis and interpretation of small-angle scattering data. Information on accessing SAS facilities is also provided. The bulk of the chapter is dedicated to recent examples in which SAS methods have been applied to gain new knowledge of the structure and design of encapsulated food ingredients.

This chapter covers the basic concepts of the scattering of light and other electromagnetic waves by spheres and cylinders, based on the exact calculation method of Gustav Mie. Results provide the scattered field complex amplitudes, as well as the angular distribution of scattered intensities and the scattering cross-sections taking into account the different polarizations of the incident and scattered waves. Morphology dependent resonances, such as localized surface plasmons and whispering gallery modes, are addressed. Then the dipolar formulation for small particles is reviewed, introducing the concept of particle polarizabilities. The Rayleigh and quasistatic approximations for very small particles are presented, emphasizing its distinction from the dipolar approximation. Further, the interplay of quadrupolar and dipolar resonant excitations, leading to interference phenomena like the Fano lines and Kerker effects, all related to directional scattering, are discussed.

Invariant Imbedding T-matrix Method for Light Scattering by Nonspherical and Inhomogeneous Particles propels atmospheric research forward as a resource and a tool for understanding the T-Matrix method in relation to light scattering. The text explores concepts ranging from electromagnetic waves and scattering dyads to the fundamentals of the T-Matrix method. Providing recently developed material, this text is sufficient to aid the light scattering science community with current and leading information. Enriched with detailed research from top field experts, Invariant Imbedding T-matrix Method for Light Scattering by Nonspherical and Inhomogeneous Particles offers a meaningful and essential presentation of methods and applications, with a focus on the light scattering of small and intermediate particles that supports and builds upon the latest studies. Thus, it is a valuable resource for atmospheric researchers and other earth and environmental scientists to expand their knowledge and understanding of available tools.

This chapter provides an introduction to small angle x-ray scattering for the characterization of nanoparticles. The basic principles and the instrumentation are described before the determination of the most relevant parameters is discussed. These parameters are the size, especially the mean particle diameter for spherical particles, the size distribution width, and the number concentration of nanoparticles in liquid suspensions. Standardization in the field is touched upon, and examples for achievable uncertainties are provided. Finally, dedicated investigations of core–shell nanoparticles are presented.

There are many situations when it is desirable to estimate not only a diameter of the nanoparticles but also their composition and the composition of the interface between nanoparticles and surrounding matrix. Ion beam analysis methods, such as medium energy ion scattering spectroscopy and low energy ion scattering, offer distinctive advantages. This chapter will provide a background discussion of ion beam analysis (IBA) methods and give their advantages and limitations for nanoparticle characterization. To illustrate the applications of IBA methods to the characterization of ensembles of nanoparticles, several examples will be presented with the methodologies involved.

This chapter reviews the fundamental physics and associated limitations of semiconductor lasers operating across the mid-infrared (MIR) range of 2–20 μm. Using a combination of temperature and hydrostatic pressure dependence techniques, we have shown how short-wavelength 1.9–3.7-μm type I quantum well interband devices are dominated by Auger recombination, the nature and type of which depends upon the wavelength. In the intermediate wavelength range (3–7 μm), interband type II “W” lasers offer significant performance improvements despite the reduced wavefunction overlap. Quantum cascade lasers dominate at the longest MIR wavelengths with performance limited by intervalley scattering and leakage processes.

In this chapter, the use of small-angle neutron and X-ray scattering for the structural characterization of clay suspensions and composite systems is described. In particular, a general introduction to the scattering theory, which will serve as a basis to understand data treatment and analysis, is provided. We also introduce the fundamental steps involved in the analysis of small-angle scattering data, putting emphasis on typical features arising from samples containing clay nanoparticles. Finally, the potential of the small-angle scattering technique to probe clay-contaning systems at rest and under stress is depicted on the basis of selected literature examples. Goal of this chapter is to provide the reader with a broad overview of the small-angle scattering technique and with inspiring experimental reports.

Two methods for passive cooling are introduced in this chapter, namely radiative cooling and cool paint. These are notably different from the more commonly known methods of heat absorption and rejection. Radiative cooling makes use of the natural black-body radiation of everyday objects, combined with the atmospheric transmission window at mid infra-red wavelengths. Cool paint incorporates particles with sizes comparable to the wavelength of visible and near infra-red light, thus is effective at scattering solar irradiation. This chapter introduces the basic physics behind these phenomena, reviews recent development and use cases of these passive cooling technologies, and discusses their potential impact on reducing building heat envelope gain and air-conditioning usage.

Scattering techniques are powerful tools to elucidate morphological features in compatibilized polymer blends. The techniques mainly include X-ray scattering, light scattering, and neutron scattering. In specific, small-angle X-ray scattering (SAXS), laser light scattering, small-angle light scattering (SALS), and small-angle neutron scattering (SANS) are widely used to probe the nano- to micro-sized domains in compatibilized blends. The advantages of ultra-small-angle scattering (USAS) techniques over small-angle scattering techniques are also discussed in the current chapter. The determination and evaluation of morphological parameters which characterize the compatibilization effect in polymer blends such as correlation length, specific surface area, and interfacial thickness using scattering techniques are discussed with suitable examples. Scattering techniques provide important information to study detailed phase behavior of miscible polymer blends. In addition, the ability of scattering techniques to follow the phase separation kinetics and mechanism of micromechanical deformation in compatibilized polymer blends is included.

This chapter summarizes the series of different developments and investigations on in situ coupling of rheology with small-angle scattering (rheo-SAS) measurements of colloidal particle suspensions. This coupling allows us to directly correlate microscopic particle–particle interaction with macroscopic suspension behavior under different physical and chemical environments. This summary provides a better understanding of the basic phenomena/theory associated, historical development and current status of rheo-SAS, and also discusses its applicability and limitations/variations to different types of concentrated particle suspensions. Two different rheo-SAS methodologies, i.e., rheo-SAXS (small-angle X-ray scattering) and rheo-SANS (small-angle neutron scattering), are introduced and discussed in terms of their similarities/differences as well as strength/uniqueness. In this article, aqueous suspensions composed of colloidal particles, including metal oxide particles and their composites with clay particles and polymers, are introduced as examples. The research gaps are identified and specific future perspectives are discussed to further enhance the use of this useful coupling, and its application toward the transition from the evaluation of simple particle suspension systems to more complex particle suspension systems that fit more with the interest and needs of particle processing industries.

This chapter aims to present a new approach in optical fiber sensors using side coupling of light into the core modes of plastic optical fiber (POF) coated with zinc oxide (ZnO) nanorods. The approach employs ZnO nanorods grown on POF to enhance coupling inside the fiber by scattering light. Structuring the growth of ZnO to specific regions allows scattering from different segments along the fiber to enhance the total coupled power. According to this capability approach, various sensing applications can be performed based on needs to develop a low-cost, high sensitivity and uncomplicated sensor system.

Due to the fast growing field of nanotechnology in the 21st century, production of the materials able to interact with light for particular optical purposes is under the focus of many research communities all around the world. Plasmonic nanomaterials are among those structures which have been spotlighted due to their exotic properties originating from their plasmon resonance and their great potential for being the host of applications ranging from optics to energy. In this chapter, we overview different aspects of plasmonic nanocomposites, from fundamental ones (i.e., absorption and scattering) to fabrication and tailored parameters. In addition, the new concept of plasmonic nanocomposites with specular reflection is also presented and discussed along with its diverse applications in the field of energy-saving solar materials. The prospective outlook introduces a new class of molecular plasmonic composites operating based on the oscillating dipole of photoswitchable molecules.

This chapter focuses on synchrotron-based characterization of well-defined cluster-based catalysts, with main focus on in situ characterization of size and composition selected subnanometer under reaction conditions by using X-ray absorption and scattering techniques, linked to the evolution of the catalytic performance.

Hyper-Rayleigh scattering (HRS) is a parametric optical effect in which two incident photons of frequency ω are annihilated to create a scattered photon of frequency 2ω. Unlike second harmonic generation (SHG), the HRS signal is isotropic, incoherent, and dephased with the excitation photon. HRS has been widely used to investigate novel materials with potential for the development of technologies, such as more efficient frequency doubling, high-resolution microscopy, fast electro-optic modulation, ultrafast lasers, and even to identify the interaction and affinity between biological molecules. In this chapter, we describe the potential of the HRS technique to investigate the first-order hyperpolarizability of organic molecules. For that, we initially present fundamentals of the first-order hyperpolarizability in materials. Theoretical approaches applied to estimate the first-order hyperpolarizability are also presented. These approaches employ different quantum chemical methods combined with a numerical or analytical scheme. Three of the most commonly used schemes, namely the finite field (FF) scheme, the sum-over-states (SOS) scheme, and the coupled-perturbed scheme, are briefly described. These approaches are used to aid in the understanding of the fundamental aspects that can be exploited, at the molecular level, to reach remarkable first-order hyperpolarizability (>10−27 cm5/esu). Moreover, we present in detail different experimental setups used to quantify in HRS experiments. Finally, recent results about the first-order hyperpolarizability are described and discussed for organic molecules with distinct molecular structures, as well as the use of the HRS effect as a technique to quantify specific interactions of biological materials.

Random lasers are photonic sources of coherent emission, which differ from conventional lasers because their optical feedback mechanism is provided by a scattering medium rather than by a conventional set of mirrors. In general, nanoparticles and a gain medium form a nanocomposite with laser properties when appropriately pumped. In this chapter, we review the development and some applications of nanocomposite-based organic random lasers and fiber random lasers. Considering the fascinating growth of the field over the last 25 years, this chapter will give an overall insight into the state-of-the-art literature for random lasers and fiber random lasers, with examples for nanocomposites mainly exploiting dyes and nanoscatterers, including both dielectric and metallic.

In this chapter the fundamentals and applications of light scattering by isolated dielectric nanoantennas are introduced. Both theoretical concepts and experimental realizations of several types of dielectric nanoantennas are presented, with particular emphasis in the far-field interference effects arising from the simultaneous excitation of electric and magnetic optical modes in those systems. We start by considering the simplest case: a single small dielectric particle, and we show how scattering anisotropy and strong directionality can be achieved. We subsequently present several strategies towards obtaining more sophisticated nanoantennas, with enhanced and more complex performance. In particular, we cover multi-particle systems, complex geometries and higher-order multipolar effects as well as substrate-induced effects, and we show how these can be used to tailor the scattering characteristics of the nanoantennas.

We describe the scattering properties of planar metasurfaces composed of arrays of dielectric resonators supporting both electric and magnetic Mie resonances. We focus on the study of metasurfaces with such functionalities as perfect reflection, perfect transmission, and perfect absorption of light at the normal or oblique incidence. Each effect is presented in its simplest form for the cases of electric and magnetic dipole resonances. Generalizations to higher orders and higher numbers of multipoles are discussed as well.

Outlines image formation theory and computer-aided interpretation in transmission electron microscopes (TEMs). (i) Near-axis electron ray optics; the transition to electron wave optics; spherical aberration, defocus and astigmatism. (ii) Beam-specimen interactions for weak (thin) specimens; multiple scattering; Bloch wave propagation in crystals; inelastic scattering; negative staining of biological specimens. (iii) Linear imaging: complex Fourier space filters modelling imaging of weakly scattering objects; phase and amplitude object components transferred by separate filters (contrast transfer functions or CTFs), and superposed in the image; coherence envelopes averaging CTF over a range of incident beam directions and focus levels; tilted-beam imaging; the charge density approximation. (iv) Nonlinear imaging, also with imperfect coherence; scanning transmission microscopy (STEM) and the reciprocal relationship with TEM. (v) Image analysis and object reconstruction: simple inverse filtering leaving gaps in the transform; using differently focused images to fill the gaps in single image transforms, and to separate the phase and amplitude components; 3D reconstruction; averaging images to recover signals buried in noise; using differently recorded images to eliminate inelastic contributions; ptychography; holography. (vi) Resolution, contrast, noise and radiation damage: the limitations imposed by electron shot noise (counting statistics); the inter-relation of resolution and contrast.

When ions are extracted from the nano-aperture ion source, they inevitably interact with the neutral particles. In this chapter, a model for such interactions is presented. An important finding is that the current and the brightness tend to keep increasing with increasing particle density, despite increasing ion-neutral scattering. Another result is that the spread in energies in the beam can be reduced as a consequence of more ion-neutral scattering. The model developed forms a basis to be used in simulations that also consider coulomb interactions. Besides presenting a model for advanced calculation, simplified analytically expressions are introduced that can help to understand a particular configuration or to quickly estimate the performance.

The main goal of this chapter is demonstrating realistic simulations of the nano-aperture ion source. The optical effects due to the electric fields, the ion-neutral scattering, and Coulomb interactions are studied simultaneously using Monte-Carlo ray tracing. Two rather unusual coulomb-interactions were taken into account, namely, surface induced charge, and electron-ion scattering. Ion-to-ion coulomb repulsion is found to pose an ultimate limit to the achievable brightness. The effect is relevant inside the chip, but also in the region where the beam is accelerated up to high voltage. In a realistic configuration the simulations predict a brightness of about 3 × 10 6 A/m2 sr V in combination with an energy spread of 1 eV. Interestingly, the attainable brightness is not very sensitive to the geometry, nor was it very dependent on the noble gas species. To achieve the best performance, electric fields close to 10 kV/mm should be used, inside and outside of the gas chamber.

Optics studies the behavior of light, or the properties of transmission and deflection of other forms of radiation. It forms the basis of optical transducers used in a variety of applications from imaging and spectroscopy to light-based manipulation and manufacturing in life sciences, chemistry, physics, and engineering. Optical transducers typically offer high sensitivity, combined spatial and spectral measurements, and detection with no direct contact to the objects under investigation. There are many types of optical transducers. In optical waveguides, there are several high-contrast modes available for light transmission, sensing, and imaging. Disadvantages include the need for the optical transducers to be transparent at the wavelength used for sensing, the use of labels, interferences, and issues arising from fluorophore decay in fluorescence imaging. In this chapter, we describe molecular sensors based on optical transduction. Lights interact with molecules in various ways, which are observed as transmission, scattering, fluorescence, and other forms of optical readout. We explain principles of optics used for molecular sensing and describe the instrumentation for optical measurements. The chapter starts with the introduction of the basic electromagnetic theory, followed by discussions on waveguides and sensors based on waveguide structures, and surface plasmon resonance-based (SPR) sensors. Lastly, theories and practices of optical spectroscopy techniques are described. Methods discussed include absorption and fluorescence microscopy and spectroscopy, static and dynamic light scattering, Doppler velocimetry, Raman spectroscopy, and near-field optical microscopy.

Biological tissue has a complex structure and exhibits rich spectroscopic behavior. Light of longer wavelength is less scattered by typical tissue, yet it is unexpectedly scattered more into the forward directions (the anisotropy of light scattering increases) within the visible and near-infrared (NIR) spectral range as revealed by some thorough measurements. We present a plum pudding random medium (PPRM) model for biological tissue to account, for the first time, for the observed spectroscopy of tissue light scattering and its anisotropy. PPRM succinctly describes tissue as a superposition of distinctive scattering structures (plum) embedded inside a fractal continuous medium of background refractive index fluctuation (pudding). PPRM faithfully reproduces the power law wavelength dependence of tissue light scattering and attributes the “anomalous” trend in the anisotropy to the plum. As light scattering is the key factor hampering the depth and resolution of optical biomedical imaging, PPRM provides much needed quantitative model of light scattering by biological tissue to gauge the merits of biomedical imaging with light of varying wavelengths. Optical breast and brain imaging are used as two examples to compare the performance of imaging in NIR and shortwave infrared (SWIR) spectral windows.

Dielectric metamaterials create a low-loss platform for a variety of applications in photonics involving a complex manipulation of the amplitude, polarization, and phase of light. However, for many applications it is important to understand how an artificial periodic system operating as a photonic crystal with the properties dominated by the Bragg scattering can transform into a metamaterial described by effective parameters. This chapter provides a comprehensive overview of the transitions between photonic crystals and metamaterials. As an example, we consider the structures composed of dielectric rods arranged in a periodic lattice. The metamaterial regime is defined by a polariton-like feature in the photonic bandgap diagram below all Bragg stop-bands created by the periodicity. This definition makes it possible to introduce the concept of a photonic phase diagram for the metamaterial and photonic crystal regimes as a function of the geometric parameters and dielectric rod permittivity. Transition between the photonic crystal and metamaterial “phases” is accompanied by a dramatic modification of the electromagnetic field patterns in the wave scattering. In addition, we describe the existence of epsilon-near-zero regime, stability of the metamaterial bandgap spectra in the presence of disorder, experimental studies of dielectric metamaterials for the microwave frequencies, and also discuss practical realizations of silicon-based metamaterials operating in the visible frequency range.

A measurement of beam-helicity asymmetries for single-hadron production in deep-inelastic scattering is presented. Data from the scattering of 27.6 GeV electrons and positrons off gaseous hydrogen and deuterium targets were collected by the HERMES experiment. The asymmetries are presented separately as a function of the Bjorken scaling variable, the hadron transverse momentum, and the fractional energy for charged pions and kaons as well as for protons and anti-protons. These asymmetries are also presented as a function of the three aforementioned kinematic variables simultaneously. (C) 2019 The Author. Published by Elsevier B.V. We gratefully acknowledge the DESY management for its support, the staff at DESY and the collaborating institutions for their significant effort. This work was supported by the State Committee of Science of the Republic of Armenia, Grant No. 18T-1C180; the FWO-Flanders and IWT, Belgium; the Natural Sciences and Engineering Research Council of Canada; the National Natural Science Foundation of China; the Alexander von Humboldt-Stiftung, the German Bundesministerium fur Bildung und Forschung (BMBF), and the Deutsche Forschungsgemeinschaft (DFG); the Italian Istituto Nazionale di Fisica Nucleare (INFN); the MEXT, JSPS, and G-COE of Japan; the Dutch Foundation for Fundamenteel Onderzoek der Materie (FOM); the Russian Academy of Sciences and the Russian Federal Agency for Science and Innovation; the Ikerbasque, Basque Foundation for Science, the Basque Government, Grant No. IT956-16, and MINECO (Juan de la Cierva), Spain; the U. K. Engineering and Physical Sciences Research Council, the Science and Technology Facilities Council, and the Scottish Universities Physics Alliance; as well as the U.S. Department of Energy (DOE) and the National Science Foundation (NSF).

Work on theories of gas–surface interactions received a strong impetus from advances in experimental physics in the early part of the last century, notably from the work of Stern and coworkers on verifying the Maxwell–Boltzmann distribution and the work of Roberts in measuring the energy accommodation coefficient. Much of the subsequent experimental work has involved gases made up of heavy mass atoms with large incident energies and relatively high surface temperatures, which are the conditions under which the scattering can be described with classical physics. In this paper a straightforward theory of classical gas–surface scattering is considered and applied to the analysis of a wide variety of experiments. The theory depends on limited information about the nature of the actual particle–surface interaction potential but does correctly account for the necessary laws of conservation of energy and momentum. Analysis of well-controlled experiments in the classical regime involving rare gases scattering from liquid, metal, and insulator surfaces is shown to yield a great deal of information about the atom–surface interaction and also reveals limitations on what such experiments are capable of revealing about the collision process.

This chapter describes the most commonly used methods for computing collisional cross sections of ions in ion mobility and ion mobility-mass spectrometry studies: the Projection Approximation, Projected Superposition and Local Collision Probability Approximations, Exact and Diffuse Hard-Spheres Scattering models, and the Trajectory Method. After an introduction that briefly overviews the kinematics and theory behind the methods, commonalities and differences between their most widely used implementations are explored. Advantages and disadvantages, as well as typical accuracy, relative computational speed, and limitations, of each of these methods are discussed. Finally, a view towards future advances in computing collisional cross sections is laid out.

Knowledge of the atomic configuration of a material is important for understanding its properties. Among various experimental techniques, the diffraction method determines the atomic positions in material structures in a straightforward way through the interference between the waves that used as the probe. This chapter provides a basic overview of diffraction methods and their applications to determine the structures of surfaces and two-dimensional atomic layers, focusing on the use of electron and positron beams. We start with the well-known Bragg equation to interpret where diffraction spots appear in a pattern, and we then extend it to a more general case by employing 2D reciprocal-lattice rods, the Ewald sphere, and the Laue condition. We introduce atomic scattering factor, refraction effect, and penetration depth to understand how information is obtained from the spot intensities. We also discuss the differences in the diffraction intensities produced by electrons, positrons, and X-rays. We describe both kinematical and dynamical diffraction theories for calculating the diffraction intensities produced by X-rays, electrons, and positrons. After showing the surface sensitivity of positrons, we review some typical examples of structural analyses (Ag/Si(111), In/Si(111), graphene/Co(0001) and graphene/Cu(111), silicene/Ag(111), and germanene/Al(111)) obtained using positron diffraction. Finally, we briefly describe future prospects for surface structure analysis using diffraction methods.