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In this chapter, we will explore how to describe the position and momentum of a particle in quantum mechanics, and how we set up its Schrodinger equation. To this end, we need to work out how to describe the momentum and energy for a particle. We will conclude with a description of a bizarre phenomenon called quantum tunnelling, which is now widely used in advanced microscopes, and with a qualitative overview of the quantum mechanical foundations of chemistry.

We demonstrate a methodology for predicting particle removal efficiency of polypropylene-based filters used in personal protective equipment, based on quantification of disorder in the context of methyl group orientation as structural motifs in conjunction with an Ising model. The corresponding Bragg-Williams order parameter is extracted through either Raman spectro-scopy or scanning electron microscopy. Temperature-dependent analysis verifies the presence of an order-disorder transition, and the methodology is applied to published data for multiple samples. The result is a method for predicting the particle removal efficiency of filters used in masks based on a material-level property.

So far we have been ignoring particle characteristics such as spin, helicity and chirality. We will view these characteristics from a wave perspective instead of the (in quantum mechanics) more usual particle perspective.

The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 14 million people globally. Recently, airborne transmission has been postulated to be a major contributor to the spread of the novel coronavirus, especially in enclosed public spaces. While many studies have demonstrated positive correlations between atmospheric pollutants and SARS-CoV-2 infection, the impact of indoor air pollutants on airborne transmission has been largely overlooked. In particular, laser printers are a primary source of particle emission that increases the concentrations of particulate matter in indoor atmosphere by releasing substantial quantities of electrostatic fine particles, at rates comparable with tobacco smoking and incense burning. We hypothesized that particles emitted from laser printers present a potential risk factor for the transmission of SARS-CoV-2 in offices and other indoor environments with high user occupancy. To test this hypothesis, we reviewed recent knowledge on the characteristics of particles emitted by laser printing, including their emission rates and accumulation in indoor air, electrostatic charges, localized emission and subsequent particle diffusion in relation to the human breathing zone. We then discuss the potential impact on the transmission of SAR-CoV-2 in indoor spaces. We found that emission rates from laser printers ranged from 108 to 1012 particles min-1, and these fine particles typically remain suspended for prolonged periods in indoor air. Electrostatic charges carried by these particles can reach 260-379 e per particle, thus enhancing their surface adsorption and deposition in human airways. Localized emission by laser printers and subsequent diffusion highly increase particle concentrations near the human breathing zone.

Models for mass transfer across membranes are divided into those in which the membrane represents the main transport resistance and others in which additional resistances are formed by concentration boundary layers and particle layers. Since mainly porous membranes are used in AO, the pore model is derived for membrane-controlled mass transfer. Concentration boundary layers may develop if permeable components are diffusively transported along a gradient from bulk to wall concentration, or if impermeable components concentrate at the membrane surface. By establishing mass flow balances around a differential membrane cross section (a membrane element), equations are derived describing the removal rates of solvents and dissolved or dispersed molecules and its dependencies on geometrical and operational parameters. These equations will be used for the different processes in AO.

The particle movement on a surface which rotates around a vertical axis is considered in the article. The surface’s meridian is the parabola’s branch, offset from the axis of symmetry by a given value. When a particle hits the surface in the lower part of the segment, it accelerates with a simultaneous upward movement. Such movement is characterized by a change in relative (sliding) speed and absolute speed. The relative velocity firstly increases and then decreases to zero when the “sticking” of the particle. The absolute velocity of the particle increases all the time and becomes constant after its “sticking”. For the surface of a sieve with parabola meridian, the “sticking” of the particle occurs in a narrow range of changes in the meridian rise angle. As the angular velocity of the sieve rotation increases, this range increases very slowly. Differential equations of relative particle displacement are compiled and solved. Graphs of particle movement trajectories and velocity change are constructed. The regularity of the particle movement during it rises along the surface is found out. The obtained analytical dependencies allow determining the influence of structural and technological parameters on the movement process.

The problem of particle motion around a particle in a shear flow is considered by numerically for conditions of weightlessness and normal earth gravity. n. The minimum distance between liquid small drops and a streamlined drop is shown.

How different wave modes are driven, is a central issue in space plasma physics. A practical problem is that often only indirect evidence of the driver can be identified in observations. The plasma environment is complex and variable and already a small difference in background or initial conditions may lead to widely different observable outcomes. In this chapter we discuss drivers of waves causing acceleration, transport and loss of radiation belt particles, whereas Chap. 6 discusses these effects in detail. We note that while this division is motivated in a textbook, it is somewhat artificial and the growth of the waves and their consequences often need to be studied together. For example, a whistler-mode wave can grow from thermal fluctuations due to gyro-resonant interactions until a marginally stable state is reached or nonlinear growth takes over. The growing wave starts to interact with different particle populations leading to damping or further growth of the wave. The fluxes of the higher-energy radiation belt particles are, however, small compared to the lower-energy background population, which supports the wave. Thus their effects on the overall wave activity usually remain small, although the waves can have drastic effect on higher-energy populations. Consequently, these two chapters should be studied together.

Since clay soils have a negative charge on their surface they are often used as a natural material in many industries. In recent years, in order to improve clays’ energy and sorption properties various methods of activating clay soils have been developed and widely spread. The study considers the complex effect of chemical and mechanical activation of clays on the change in its energy properties estimated by measuring the adhesion force of the particle surface. Chemical activation of clays was carried out by a solution of hydrochloric acid with a concentration of 0.1 M. Mechanical activation was carried out by exposing the soil to high pressures ranging from 25 to 800 MPa. Energy properties of particle surface of clays were evaluated using an atomic force microscope NT MDT NTEGRA Prima (Russia). The results of the studies have showed that when treating clay soils with a hydrochloric acid solution and stress pressure, the adhesion forces do not change significantly. Meanwhile, there has not been revealed any influence of treatment on the adhesion force in montmorillonite clays, while for soils of the kaolinite group a pattern was found that with increasing pressure, the adhesion forces decrease. The results obtained can be used to form clay soils with desired energy properties.

Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include tire wear, paint chips, semisynthetics (e.g., rayon), and bioplastics. Plastics commonly contain chemical additives and fillers, which may alter their toxicological potency, behavior (e.g., buoyancy), or detector response (e.g., yield fluorescence) during analysis. Field sampling methods often focus on >20 μm and even >300 μm sized particles and will thus not capture smaller microplastics (which may be most abundant and bioavailable). Analysis of a limited subgroup (selected polymer types, particle sizes, or shapes) of microplastics, while often operationally necessary, can result in an underestimation of actual sample content. These shortcomings complicate calls for toxicological studies of microplastics to be based on “environmentally relevant concentrations.” Sample matrices of interest include water (including wastewater, ice, snow), sediment (soil, dust, wastewater sludge), air, and biota. Properties of the environment, and of the particles themselves, may concentrate plastic debris in select zones (e.g., gyres, shorelines, polar ice, wastewater sludge). Sampling designs should consider such patchy distributions. Episodic releases due to weather and anthropogenic discharges should also be considered. While water grab samples and sieving are commonplace, novel techniques for microplastic isolation, such as continuous flow centrifugation, show promise. The abundance of nonplastic particulates (e.g., clay, detritus, biological material) in samples interferes with microplastic detection and characterization. Their removal is typically accomplished using a combination of gravity separation and oxidative digestion (including strong bases, peroxide, enzymes); unfortunately, aggressive treatments may damage more labile plastics. Microscope-based infrared or Raman detection is often applied to provide polymer chemistry and morphological data for individual microplastic particles. However, the sheer number of particles in many samples presents logistical hurdles. In response, instruments have been developed that employ detector arrays and rapid scanning lasers. The addition of dyes to stain particulates may facilitate spectroscopic detection of some polymer types. Most researchers provide microplastic data in the form of the abundances of polymer types within particle size, polymer, and morphology classes. Polymer mass data in samples remain rare but are essential to elucidating fate. Rather than characterizing individual particles in samples, solvent extraction (following initial sample prep, such as sediment size class sorting), combined with techniques such as thermoanalysis (e.g., pyrolysis), has been used to generate microplastic mass data. However, this may obviate the acquisition of individual particle morphology and compositional information. Alternatively, some techniques (e.g., electron and atomic force microscopy and matrix-assisted laser desorption mass spectrometry) are adept at providing highly detailed data on the size, morphology, composition, and surface chemistry of select particles. Ultimately, the analyst must select the approach best suited for their study goals. Robust quality control elements are also critical to evaluate the accuracy and precision of the sampling and analysis techniques. Further, improved efforts are required to assess and control possible sample contamination due to the ubiquitous distribution of microplastics, especially in indoor environments where samples are processed.

The application of enhanced oil recovery (EOR) nanotechnology has opened an important field of fundamental science and engineering studies offering a wide range of research interests. Owing to the physicochemical properties of some nanoparticles (NPs), several mechanisms have been employed to functionalize the surface of nanoparticles to improve the interface between organic and inorganic molecules. In this study, a β-1,3-glucan schizophyllan organopolymer (SPG-OH) was grafted onto hydroxyl activated silica NPs (SiO2–OH NPs) via a sol-gel thermo-condensation polymerization process to further improve the surface properties of the SiO2 NPs. The structure of the nanocomposite material (SPG-g-SiO2 NPs) was characterized using different spectroscopic experiments such as FTIR, FESEM, XRD and TGA. From the spectroscopic experiments, the grafting bonding between the SPG-OH and the SiO2–OH NPs was established in the FTIR spectra of the SPG-g-SiO2 NPs due to the disappearance of the characteristic absorption wavelength corresponding to −OH at 3303–3500 cm−1 leading to strong chemical interactions between the SPG and SiO2 NPs. Although, there was noticeable slight modification of the size and environment of the SPG-g-SiO2 NPs composite due to surface activity in the FESEM imaging, however, a large proportion of these grafted particles were within 20–30 nm indicating minimum particle aggregations. The XRD experiments further confirmed that no surface morphology change from amorphous to crystalline was observed due to the appearance of diffraction shoulder at 20 2θ in the diffractogram. Similarly, the grafted material had a 53% residual mass after subjected to 800 ℃ decomposition temperature, indicating thermal stability. Thus, this study suggests that a composite of the SPG-g-SiO2 NPs could potentially be utilized in the EOR nanotechnology, such as in smart nanofluid injection or combined with surfactant in foam flooding for enhancing oil recovery.

Seasonal frozen ground is mainly distributed in the north of 30°N, with an area of 5.137 million km2, covering approximately 53.5% of the national territory in China. In recent years, with the rapid development of Chinese railway, many lines have been built passing through seasonal frozen areas. At the same time, with the increase of traffic volume, transport capacity would become larger year by year, so the requirements of low frost heave for the subgrades would also be made more stringent. Based on the stress release holes (SRHs), several special experiments are designed and implemented in a one-dimensional freezing condition from a sample’s top to bottom, which are targeted to verify the effectiveness and feasibility of SRHs on decreasing frost heaves. Also, a measure to decrease frost heave of subgrade filler in seasonal frozen area is proposed. There are seven laboratory tests carried out in the open system. And the frost heave effect of saturated soil samples within 72 h was explored with a certain HRA set as 4% and SRHs filling materials.

For many years, magnetic particles attracted a lot of interest in many fields, mainly including biomedicine. Recently, development of innovative strategies to tune the unique properties of magnetic nanoparticles for specific applications as theranostic agents has become one of the most challenging goals. This paper provides an overview of the synthesis, modification, and functionalization of magnetic nano- and microparticles. Special attention was paid to iron oxide composites used in cell separations and theranostics, such as anticancer drug delivery, diagnosis, and/or therapy of autoimmune and brain disorders. Last, but not the least, phenolic compound-modified magnetic particles were used as antioxidants or silver-containing carriers as antibacterial agents in in vitro and in vivo studies. Magnetic microparticles can be also incorporated in biosensors, exemplified by thionine-conjugated magnetic poly(carboxymethyl methacrylate-co-ethylene dimethacrylate) particles that showed higher enzymatic activity than nonmagnetic particles. Magnetic nano- and microparticles were characterized by a range of physicochemical methods, including transmission electron microscopy, dynamic light scattering, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy, in terms of determination of particle morphology (size and its distribution), specific surface area, magnetic, and chemical properties. The chemical composition and crystallinity were confirmed by X-ray photoelectron spectroscopy. Moreover, the interactions between the magnetic particles and cells and/or other biological species were described.

Sandstone–mudstone particle mixture (SMPM) is often used as a main filling material in many agriculture-related and civil engineering works such as in rockfill dams and filling foundations. The SMPM was found crushed seriously since it is mixed with mudstone particles. In this study, the compressive rheological test was conducted to investigate the influence of different vertical stress and mudstone particle content on the particle breakage of SMPM. Research findings suggested that particle breakage of SMPM in the conditions of different pressure and mudstone particle content ranged between 4.24 and 24.34% and rose along with the increase in vertical pressure and mudstone particle content. A power function relation between particle breakage and vertical pressure was proposed. It was found that, with small confining pressure, the particle breakage of SMPM particles calculated by the proposed prediction formula was larger than that of rockfill materials. The particle breakage prediction formulas of rockfill materials underestimated the particle breakage of SMPM during the small confining pressure.

The kinetic theory of gases is extended to particulate flow where the interaction between particles is not conserved. Granular temperature and the equation of state for the particle phase is developed. Granular temperature is defined as the average of the random kinetic energy, with the conversion factor of the Boltzmann constant. For dense flows, in addition to the kinetic and collisional stresses using the kinetic theory approach, a model account for the frictional stresses based on soil mechanics principles is presented. Gas/particle flows are inherently oscillatory and they manifest in non-homogeneous structures. Therefore, the drag force for different regimes of non-homogeneous gas/solid flow systems is discussed. Fluid/particle systems are composed of particles of different properties, in which transfer of momentum and segregation by size or density occurs during the flow, thus the kinetic theory was extended to modeling of multitype particle flow using the kinetic theory approach. Finally, heat and mass transfer equations for gas/solid flow systems are presented.