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Availability of a powdered internal standard method developed in the previous report has been investigated in detail for geological, mineralogical, environmental and biological samples. It is found that this method is effective for various powdered samples composed of high-Z elements. A computer program for correcting self-absorption of x-rays, which is based on the method we previously reported, was developed and it has been applied to soil samples of varied thickness. As a result, it is found that the method is quite effective even for a pretty thick target where particles overlap with each other. Moreover, the method was applied to several rock samples, which were prepared by grinding and consist of particles of divergent size, and found to be applicable. Lastly, the powdered internal standard method was applied to a biological sample and found to be almost satisfactory, too. These results demonstrate the availability of the powdered internal standard method combined with the method of x-ray-absorption correction for samples in many research fields.

Heavy loads of aerosols in the air have considerable health effects in individuals who suffer from chronic breathing difficulties. This problem is more acute in the Middle-East, where dust storms in winter and spring transverse from the neighboring deserts into dense populated areas. Discrimination between the dust types and association with their source can assist in assessment of the expected health effects. A method is introduced to characterize the properties of dense dust clouds with passive IR spectral measurements. First, we introduce a model based on the solution of the appropriate radiative transfer equations. Model predictions are presented and discussed. Actual field measurements of silicone-oil aerosol clouds with an IR spectro-radiometer are analyzed and compared with the theoretical model predictions. Silicone-oil aerosol clouds have been used instead of dust in our research, since they are composed of one compound in the form of spherical droplets and their release is easily controlled and repetitive. Both the theoretical model and the experimental results clearly show that discrimination between different dust types using IR spectral measurements is feasible. The dependence of this technique on measurement conditions, its limitations, and the future work needed for its practical application of this technique is discussed.

In this paper, we apply quantum cosmology to investigate the early moments of a Friedmann–Lemaître–Robertson–Walker (FLRW) cosmological model, using Hořava–Lifshitz (HL) as the gravitational theory. The matter content of the model is a dust perfect fluid. We start studying the classical model. Then, we write the total Hamiltonian of the model, quantize it and find the appropriate Wheeler–DeWitt equation. In order to avoid factor ordering ambiguities, in the Wheeler–DeWitt equation, we introduce a canonical transformation. We solve that equation using the Wentzel–Kramers–Brillouin (WKB) approximation and compute the tunneling probabilities for the birth of that universe ($\text{T}{\text{P}}_{\mathrm{\text{WKB}}}$). Since the WKB wave function depends on the dust energy and the free coupling constants coming from the HL theory, we compute the behavior of ${\mathrm{\text{TP}}}_{\mathrm{\text{WKB}}}$ as a function of all these quantities.

Bianchi Type I dust filled universe in the frameworks of Lyra geometry in the presence of magnetic field is investigated. To get the deterministic model of the universe, we have also assumed that the eigenvalue of shear tensor is proportional to the expansion (θ) in the model. This leads to A = (BC)ⁿ where A, B and C are metric potentials and n is a constant. The physical and geometrical aspects of the model related with astronomical observations are also discussed.

Motivated by the expanding interest in complex plasmas, we discuss the equivalent photon charge in dusty electron-ion plasmas. Particularly, we investigate the dusty plasma response in terms of the electron density perturbation driven by electromagnetic waves. The resulting polarization of this plasma medium caused by the photon ponderomotive force of the electromagnetic radiation pressure gives rise to an effective photon electric charge. We determine the acquired photon charge in terms of the involved characteristic parameters. More precisely, here we derive an explicit expression of the photon charge which is found to depend strongly on the free electron density and the photon frequency. Such a photonic charge is relevant for dealing with the photon–plasma couplings in most plasma mediums, namely of the early Universe.

In recent years it is generally believed that we should consider positive vacuum energy density or cosmological constant. Also as higher dimensional theory is important at the early stages of the Universe, so it will be interesting to study classical tests of cosmology in a higher dimensional generalized Kantowski–Sachs model. For matter field, we consider dust and a cosmological constant and examine which are physically permissible.

Different regions of Iran are influenced by dust storms since they are located in the arid and semi-arid zone and due to their plain structure, the penetration of different synoptic systems, and adjacency with desert and important dust centers. This research investigates the effect of dust sedimentation on the yield of irrigated and rainfed wheat in four neighbouring provinces and on wheat production in Iran (Khuzestan, Ilam, Kermanshah, and Lorestan). Data are for the crop years from 2011–2012 to 2018–2019. For higher accuracy, the research studies irrigated and rainfed wheat systems separately with the panel model of the Just–Pope function. In the Just–Pope stochastic function, the effects of inputs on two indices of mean yield and yield variance are studied simultaneously. Based on the results, the risk function of irrigated wheat is significantly influenced by the variables of machinery, labour, and dust at the 1% level and by the variables of water and precipitation at the 10% level. The most influential variable in this function is dust (3.03%). In the risk function of rainfed wheat, all variables have a significant impact on production fluctuations at the 1% level. The most influential factor is the temperature (0.86%). Furthermore, the results reveal that the variable of the number of dusty days is significant in the production of irrigated and rainfed wheat at the 15% and 1% levels, respectively. The effect of this variable on rainfed wheat is negative and 0.101%. In this regard, it is necessary to develop dust-specific projects in the agricultural sector and estimate the cost imposed by this phenomenon.

High-resolution Airborne Wide-band Camera (HAWC$+$) is the facility far-infrared imager and polarimeter for SOFIA, NASA’s Stratospheric Observatory for Infrared Astronomy. It is designed to cover the portion of the infrared spectrum that is completely inaccessible to ground-based observatories and which is essential for studies of astronomical sources with temperatures between tens and hundreds of degrees Kelvin. Its ability to make polarimetric measurements of aligned dust grains provides a unique new capability for studying interstellar magnetic fields. HAWC$+$ began commissioning flights in April 2016 and was accepted as a facility instrument in early 2018. In this paper, we describe the instrument, its operational procedures, and its performance on the observatory.

Dusty plasmas are complex systems where new phenomena arise from the presence of solid dust particles inside a plasma. Dust particles acquire a negative charge by attaching free electrons and are thus trapped in the plasma. This charge loss can be drastic for the plasma equilibrium and instabilities can appear due to the strong interdependence between the dust particle cloud and the plasma. In this paper, various types of self-excited instabilities consisting in regular or chaotic oscillations, are presented. They are obtained in low pressure radio-frequency discharges where dust particles are grown by using a reactive gas or by sputtering a surface exposed to the plasma. The complex evolution scheme of these instabilities is brought to the fore thanks to various diagnostics.

Heavy loads of aerosols in the air have considerable health effects in individuals who suffer from chronic breathing difficulties. This problem is more acute in the Middle-East, where dust storms in winter and spring transverse from the neighboring deserts into dense populated areas. Discrimination between the dust types and association with their source can assist in assessment of the expected health effects. A method is introduced to characterize the properties of dense dust clouds with passive IR spectral measurements. First, we introduce a model based on the solution of the appropriate radiative transfer equations. Model predictions are presented and discussed. Actual field measurements of silicone-oil aerosol clouds with an IR spectro-radiometer are analyzed and compared with the theoretical model predictions. Silicone-oil aerosol clouds have been used instead of dust in our research, since they are composed of one compound in the form of spherical droplets and their release is easily controlled and repetitive. Both the theoretical model and the experimental results clearly show that discrimination between different dust types using IR spectral measurements is feasible. The dependence of this technique on measurement conditions, its limitations, and the future work needed for its practical application of this technique is discussed.