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In Ayurveda, Lauha (Iron) bhasma is primarily used to cure diseases related with iron deficiency in humans. It is produced from purified raw metallic iron using a combination of multi-step traditional preparation processes described in the Ayurveda literature. Here, we present results of structural investigation performed on the medicinal grade Lauha bhasma using various X-ray based techniques. Our results indicate that after several rounds of heating and cooling in specific conditions following the Ayurvedic preparation procedure, metallic iron eventually converts to a natural iron-oxide mineral belonging to the Magnetite group. Scanning electron microscopy (SEM) and X-ray standing wave assisted fluorescence measurements carried out on powdered bhasma specimen reveal that the Magnetite micro-particles in the bhasma specimen are usually present in the form of agglomerates of nano-particles. We anticipate that the Ayurvedic Lauha Bhasma has great potential for noninvasive localized target killing of cancer cells, particularly in sensitive parts of the human body such as brain, spinal cord, and lungs, via necrosis by application of an alternating external magnetic field or photo electron generation through X-rays., Comment: need further work

Energy dispersive X-ray fluorescence (EDXRF) is a widely used non-destructive technique for micro and trace multi-element analysis of materials. Conventional trials show that using laboratory assisted EDXRF measurements, one can obtain elemental detection limits in the range of {\mu}g/g to sub-{\mu}g/g level. In the present work a quantitative approach has been followed in attempting to explore how is it possible to obtain elemental detection limit in the range of ng/g by using simple EDXRF excitation (45{\deg}- 45{\deg} geometry) instead of using total reflection X-ray fluorescence (TXRF) technique, which renders relatively superior detection limits for different elements. In order to accomplish this, we recorded fluorescence spectrum from a standard reference sample (ICP-IV) in similar experimental conditions. The results show that using a very small quantity of sample on top of a thin kapton foil with a thickness ranging between 25-50 {\mu}m, as a sample carrier, the EDXRF technique may offer comparable elemental detection limits in contrast to TXRF technique.

Recent advances in grazing incidence X-ray optics using synchrotron radiation sources have stimulated the need for basic research in high quality mirror materials for novel applications. In this paper we communicate the results of the first measurements of glazing angle X-ray reflectivity (XRR) of speculum metal mirrors using synchrotron radiation sources. Our results agree with similar measurements made in polished speculum gratings by Arthur Compton and his collaborators during 1923 using ordinary X-ray tubes. Our experimental investigations are based on synchrotron radiation research facilities (Indus 2) maintained by Govt of India in Indore . Variations in the XRR with grazing angles of incidence and X-ray energy for cast, thin film and electron irradiated samples of speculum metal will be discussed in this paper., Comment: 9 Pages,7 figures and presented in National conference on Fundamental and Applied physics (NFAP- 2019) held on 12th and 13th November 2019 at Department of Physics, University College, Thiruvananthapuram.India

Atomic diffusion at nanometer length scale may differ significantly from bulk diffusion, and may sometimes even exhibit counterintuitive behavior. In the present work, taking Cu/Ni as a model system, a general phenomenon is reported which results in sharpening of interfaces upon thermal annealing, even in miscible systems. Anomalous x-ray reflectivity from a Cu/Ni multilayer has been used to study the evolution of interfaces with thermal annealing. Annealing at 423 K results in sharpening of interfaces by about 38%. This is the temperature at which no asymmetry exists in the inter-diffusivities of Ni and Cu. Thus, the effect is very general in nature, and is different from the one reported in the literature, which requires a large asymmetry in the diffusivities of the two constituents [Z. Erd\'elyi et al., Science 306, 1913 (2004).]. General nature of the effect is conclusively demonstrated using isotopic multilayers of 57Fe/naturalFe, in which evolution of isotopic interfaces has been observed using nuclear resonance reflectivity. It is found that annealing at suitably low temperature (e.g. 523 K) results in sharpening of the isotopic interfaces. Since chemically it is a single Fe layer, any effect associated with concentration dependent diffusivity can be ruled out. The results can be understood in terms of fast diffusion along short-circuit paths like triple junctions, which results in an effective sharpening of the interfaces at relatively low temperatures., Comment: 8 figures

The transparent Er, Nd co-doped Yttria ceramics with transparency around 78 percentage (in 500 - 2000 nm range without Fresnels correction) were fabricated successfully. It involved nanoparticle synthesis by coprecipitation method and sintering of pellets under high vacuum condition. The crystalline phase, particle size and element composition were confirmed by X- ray diffraction, scanning electron microscope, energy dispersive X- ray fluorescence techniques, respectively. The upconversion luminescence mechanisms involving energy transfer and non-radiative relaxation were analyzed. It is expected that, the result evolved from this study will provide better understanding of upconversion mechanism involved in Er, Nd codoped host material. The emission at both 563 nm and 1064 nm on 822 nm excitation proves potential of the ceramic material for dual mode efficient emitter., Comment: 21 pages with 9 figures

We report results of simultaneous x-ray reflectivity and grazing incidence x-ray fluorescence measurements in combination with x-ray standing wave assisted depth resolved near edge x-ray absorption measurements to reveal new insights on chemical speciation of W in a W-B4C superlattice structure. Interestingly, our results show existence of various unusual electronic states for the W atoms especially those sitting at the surface and interface boundary of a thin film medium as compared to that of the bulk. These observations are found to be consistent with the results obtained using first principles calculations. Unlike the conventional x-ray absorption measurements the present approach has an advantage that it permits the determination of depth resolved chemical nature of an element in the thin layered materials at atomic length scale resolutions., Comment: 9 figures

Nanostructures of Titanium oxide (TiO2) are being studied for many promising applications, e.g., solar photovoltaics, solar water splitting for H2 fuel generation etc., due to their excellent photo-catalytic properties. We have synthesized low-dimensional TiO2 nanoparticles by gas phase CW CO2 laser pyrolysis. The laser synthesis process has been optimized for the deposition of highly pure, nearly mono-dispersed TiO2 nanoparticles on silicon substrates. Hard x-ray standing wave-field (XSW) measurements in total reflection geometry were carried out on the BL-16 beamline of Indus-2 synchrotron radiation facility in combination with x-ray reflectivity and grazing incidence x-ray fluorescence measurements for the determination of surface morphology of the deposited TiO2 nanostructures. The average particle size of TiO2 nanostructure estimated using transmission electron microscopy (TEM) was found to closely agree with the XSW and grazing incidence x-ray diffraction (GIXRD) results., Comment: 3 pages, 2 figure

We present a unified elucidation for the role temporal coherence properties of x-rays in surface x-ray standing wave analysis, under total external reflection condition. Analytical formulas have been derived that provide a direct relation between the intensity distribution of x-ray standing wave (XSW) pattern and complex degree of coherence of the incoming x-rays. The novelty of the proposed method has been demonstrated experimentally together with the theoretical results for a real application by analyzing the distribution of metal nanoparticles on a Si mirror surface. Our results demonstrate that the modified XSW approach opens up an opportunity to unambiguously interpret structural studies of large dimension nanostructure materials of height 200nm (or more), deposited on a substrate surface.

Total reflection x-ray fluorescence (TXRF) spectroscopy has seen a remarkable progress over the past years. Numerous applications in basic and applied sciences prove its importance. The large spectral background which is a major detrimental factor in the conventional x-ray fluorescence technique, limits the element detection sensitivities of the technique to ppm range. This spectral background reduces to a great extent in the TXRF technique due to the low extinction depth of the primary incident x-ray beam. In synchrotron radiation (SR) based TXRF measurements the spectral background reduces further because of the polarization of the synchrotron x-ray beam. Here, we discuss in detail the influence of synchrotron polarization on the spectral background in a fluorescence spectrum and its significance towards TXRF detection sensitivities. We provide a detailed theoretical description and show that how anisotropic scattering probability densities of the Compton and Elastic scattered x-rays depend on the scattering angle ({\theta}) and azimuthal angle ({\phi}) in the polarization plane of the SR beam.

We have developed an algorithm (x2abundance) to derive the lunar surface chemistry from X-ray fluorescence (XRF) data for the Chandrayaan-1 X-ray Spectrometer (C1XS) experiment. The algorithm converts the observed XRF line fluxes to elemental abundances with uncertainties. We validated the algorithm in the laboratory using high Z elements (20 < Z < 30) published in Athiray et al. (2013). In this paper, we complete the exercise of validation using samples containing low Z elements, which are also analogous to the lunar surface composition (ie., contains major elements between 11 < Z < 30). The paper summarizes results from XRF experiments performed on Lunar simulant (JSC-1A) and anorthosite using a synchrotron beam excitation. We also discuss results from the validation of x2abundance using Monte Carlo simulation (GEANT4 XRF simulation).

A mobile ad-hoc network (MANET) is collection of intercommunicating mobile hosts forming a spontaneous network without using established network infrastructure. Unlike the cellular or infrastructure networks who have a wired backbone connecting the base-station, the MANETs have neither fixed routers nor fixed locations. Their performance largely depend upon the routing mechanism & nature of mobility. Earlier research hints that the Destination Sequenced Distance Vector (DSDV) routing protocol is one of the most efficient and popular protocols, as far as general parameters have been concerned.[1,6] We have experimentally evaluated, the performance metrics for network load, packet delivery fraction and end-to-end delay with DSDV Protocol using NS2 Simulator.This paper presents, the performance of DSDV protocol for four different mobility models namely: Random Waypoint, Reference Point Group Mobility, Gauss Markov & Manhattan Mobility Model having varying network load & speed. The experimental results suggest that DSDV protocol with RPGM mobility model has optimized results for varying network load and speed.

We report a detailed study of surface and interface properties of pulsed-laser deposited NiMnSb films on Si (100) substrate as a function of film thickness. As the thickness of films is reduced below 35 nm formation of a porous layer is observed. Porosity in this layer increases with decrease in NiMnSb film thickness. These morphological changes of the ultra thin films are reflected in the interesting transport and magnetic properties of these films. On the other hand, there are no influences of compositional in-homogeneity and surface/interface roughness on the magnetic and transport properties of the films., Comment: 13 pages, 7 figures, Submitted to Phys. Rev. B