Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
36,955 result(s) for "diffraction spectroscopy"
Sort by:
Polyether Ketone Ketone (PEKK) matrix composites for material extrusion additive manufacturing
Despite the widespread use of fused filament fabrication (FFF) (an extrusion-based additive manufacturing process) to manufacture end-use parts for the aerospace industry, limited materials are available within this process that can be used for structural applications in the harsh space environment. Currently available high-performance polymers need to be improved by incorporating additives within the polymer matrix to achieve multi-functional properties. Additives such as graphene, graphene oxide, carbon nanotubes and boron carbide are known to improve mechanical and thermal properties and radiation shielding. This study aims to understand if these additives can be successfully incorporated into PEKK matrix to manufacture printable filaments for FFF. Graphene, graphene oxide (GO) and boron carbide (B 4 C) were compatibilised with PEKK matrix, and their mechanical, thermal and rheological properties were analysed and compared with commercially available carbon fibre and carbon nanotube-reinforced PEKK where appropriate. As rheological properties of the formulations confirmed that they were printable, filaments for FFF were then manufactured. Graphene–PEKK was the most printable filament followed by GO–PEKK while B 4 C–PEKK was not printable. TEM images of filament cross-section showed good dispersion of graphene and graphene oxide, while boron carbide formed large agglomerates; B 4 C also presented feeding issues due to its hardness which affected its printability. Dispersion of the additives was also confirmed by studying their X-ray diffraction (XRD) patterns, and chemical structures were assessed using FT-IR spectroscopy. Finally, parts were printed using selected composite filaments, and their porosity and surface roughness were compared with neat PEKK and commercial CNT-reinforced PEKK to develop an understanding of metrology and bulk material properties of the composites.
Exploration of Photoluminescence, Colorimetric, and Decay Performance of Sm-activated CaWO4 Ceramic
This paper represents structure, photoluminescence, and colorimetric investigations of Sm-activated CaWO 4 ceramic made with the help of a solid-state reaction process. Structures of the ceramics are examined through X-ray diffraction spectroscopy. It indicates that these materials have a tetragonal structure and I4 1 /a space group without having any other secondary phase. Energy band gaps are increased with the higher concentrations of Sm dopants. Photoluminescence analyses show that concentration quenching is found at x = 0.02 Sm incorporated CaWO 4 . The critical distance of energy transfer is obtained as about 20 Å. Q-value is observed approximately equal to 6 which denotes that dipole-dipole interactions occur in the materials that create the critical energy transfer distance in them. Chromaticity values are described in that the ceramics emit orange-red color as well as excellent colorimetric parameters. Quantum efficiency of x = 0.02 Sm composition in CaWO 4 is measured under 405 nm EX wavelength. Photoluminescence decay behaviors are observed and average lifetime values are evaluated.
Refinement of anomalous dispersion correction parameters in single-crystal structure determinations
Correcting for anomalous dispersion is part of any refinement of an X-ray diffraction crystal structure determination. The procedure takes the inelastic scattering in the diffraction experiment into account. This X-ray absorption effect is specific to each chemical compound and is particularly sensitive to radiation energies in the region of the absorption edges of the elements in the compound. Therefore, the widely used tabulated values for these corrections can only be approximations as they are based on calculations for isolated atoms. Features of the unique spatial and electronic environment that are directly related to the anomalous dispersion are ignored, although these can be observed spectroscopically. This significantly affects the fit between the crystallographic model and the measured intensities when the excitation wavelength in an X-ray diffraction experiment is close to an element's absorption edge. Herein, we report on synchrotron multi-wavelength single-crystal X-ray diffraction, as well as X-ray absorption spectroscopy experiments which we performed on the molecular compound Mo(CO) 6 at energies around the molybdenum K edge. The dispersive ( f ′) and absorptive ( f ′′) terms of the anomalous dispersion can be refined as independent parameters in the full-matrix least-squares refinement. This procedure has been implemented as a new feature in the well-established OLEX2 software suite. These refined parameters are in good agreement with the independently recorded X-ray absorption spectrum. The resulting crystallographic models show significant improvement compared to those employing tabulated values.
The Properties of High-Performance Concrete with Manganese Slag under Salt Action
Manganese slag (MS) containing a certain amount of active hydration substances may be used as a kind of cementitious material. In the present study, we measured the mass, the relative dynamic modulus of elasticity (RDME), and the flexural and compressive strengths of MS high-performance concrete (MS-HPC) with added basalt fibers exposed to NaCl freeze–thaw cycles (N-FCs), NaCl dry–wet alternations (N-DAs), and Na2SO4 dry–wet alternations (NS-DAs). Scanning electron microscope energy-dispersive spectrometer (SEM-EDS) spectra, thermogravimetric analysis (TG) curves, and X-ray diffraction spectroscopy (XRD) curves were obtained. The mass ratio of MS ranged from 0% to 40%. The volume ratio of basalt fibers varied from 0% to 2%. We found that, as a result of salt action, the mass loss rate (MLR) exhibited linear functions which were inversely correlated with the mass ratio of MS and the volume ratio of basalt fibers. After salt action, MLR increased by rates of 0~56.3%, but this increase was attenuated by the addition of MS and basalt fibers. Corresponding increases in RDME exhibited a linear function which was positively correlated with MS mass ratios in a range of 0~55.1%. The addition of MS and basalt fibers also led to decreased attenuation of mechanical strength, while the addition of MS led to increased levels of flocculent hydration products and the elements Mn, Mg, and Fe. CaClOH and CaSO4 crystals were observed in XRD curves after N-DA and NS-DA actions, respectively. Finally, the addition of MS resulted in increased variation in TG values. However, the opposite result was obtained when dry–wet actions were exerted.
Microbial and Plant Assisted Synthesis of Cobalt Oxide Nanoparticles and Their Antimicrobial Activities
The development of sustainable, ecofriendly, and cost-effective methods for the synthesis of nanomaterials is an important aspect of nanotechnology these days. The present study was aimed at synthesizing cobalt oxide (Co3O4) nanoparticles by using plant extracts of Aerva javanica, bacterial isolates from rhizospheric soil of Potentilla atrosanguinea, Swertia petiolata, Senecio chrysanthemoides, and from fungus Fusarium oxysporum. X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM) techniques were used in the characterization of the synthesized nanoparticles. The bacterial strain, Bacillus subtilis, isolated from rhizosphere of Potentilla atrosanguinea (N1C1), Fusarium oxysporum, methanolic and aqueous extracts of Aerva javanica reduced the cobalt salts to cobalt oxide nanoparticles. The nanoparticles, synthesized from bacterial isolate N1C1 (Bacillus subtilis) and from Fusarium oxysporum had average particle size of 31.2 nm and 33.4 nm, respectively, whereas, the particle size of Aerva javanica was higher (39.2 nm) and all the nanoparticles were poly shaped. The nanoparticles synthesized from methanolic extract of Aerva javanica, bacterial strain (N1C1) and fungi Fusarium oxysporum showed better performance against Bacillus subtilis and P. aeruginosa, the bactericidal activity was higher against Gram-positive bacterial strains. Methanolic extracts of leaf and flower have shown a wide range of phytochemicals and higher antibacterial activity, and among all strains, Pseudomonas aeruginosa and Bacillus subtilis susceptibility was greater to extracts.
ELI Gammatron Beamline: A Dawn of Ultrafast Hard X-ray Science
The realization of compact X-ray sources is one of the most intriguing applications of laser-plasma based electron acceleration. These sources based on the oscillation of short micron-sized bunches of relativistic electrons provide femtosecond X-ray pulses that are collimated, bright, and partially coherent. The state-of-the-art laser plasma X-ray sources can provide photon flux of over 1011 photons/shot. The photon flux can further be enhanced with the availability of high repetition rate, high-power lasers, providing capacities complementary to the large scale facilities such as synchrotrons and X-ray free-electron lasers. Even though the optimization of such sources has been underway for the last two decades, their applications in material and biological sciences are still emerging, which entail the necessity of a user-oriented X-ray beamlines. Based on this concept, a high-power-laser-based user-oriented X-ray source is being developed at ELI Beamlines. This article reports on the ELI Gammatron beamline and presents an overview of the research accessible with the ultrashort hard X-ray pulses at the ELI Gammatron beamline.
An experimental study on spectroscopic analysis of alternating liquid dielectrics for transformer
Conventionally, mineral oil impregnated with solid insulating materials has been used as an insulating medium in the transformers. On the other hand, mineral oil is less biodegradable than ester oils and it has poor fire-resistant characteristics. Therefore, the conventionally used mineral oils are not satisfying the new ecological requirements. Besides that the availability of fossil fuels is also going to run out. Consequently, several investigators have tried with different kinds of edible as well as non-edible oils for using them as liquid dielectrics in the transformers. This paper attempts to prove the feasibility of Pongamia pinnata oil (PPO) as an alternate liquid dielectric for transformer. At first, solid insulating material’s deterioration study was carried out using DGA, SEM, XRD and UV–Vis spectroscopy. Alongside, thermal stability of PPO and mineral oil was analyzed through FTIR spectroscopy. DGA results show that gas-generating phenomenon was found on both the oil samples. However, the generation of combustible gas in PPO impregnated with solid insulating material is found to be lower when compared with other oils. From the FTIR analysis, it is found that the structural difference between PPO and mineral oil is negligible. However, from XRD and UV–Vis spectroscopy, it is evident that depending on the type of material, the thus emitted spectra have different bandwidth and there is variation in the absorbance intensity. When the contamination rate is higher, the absorbance intensity of the insulating oil increased. SEM analysis shows that cellulose fiber’s width has drastically decreased in case of the solid insulation material immersed in mineral oil; also, there is evidence for bond breaking.
Thin Film Electrodeposition of a Fe3(NH4)H8(PO4)6.6H2O Superphosphate Material by Oxidation of Mohr's Salt in a Phosphoric Medium
The superphosphate thin film of Fe3(NH4)H8(PO4)6.6H2O is electrodeposited using a concentrated solution of 2 M phosphoric acid and a Mohr's salt precursor (Fe(NH4)2(SO4)2.6H2O). The electrochemical oxidation of the Fe(H2PO4)+ complex present in the medium is monitored by cyclic voltammetry and shows that the deposition results from a combination of different phenomena such as diffusion and adsorption. The electrodeposition is carried out using the chronoamperometric method at a potential of 0.6 V/saturated calomel electrode. The resulting material is studied by X‐ray diffraction and has a hexagonal structure corresponding to the P31c space group, with lattice parameters of a = 9.15 Å and c = 16.86 Å; its morphology is studied by scanning electron microscopy combined with energy dispersive X‐ray spectroscopy, which shows a rod structure and confirms the presence of its constituent elements. Fourier transform infrared spectroscopy reveals lattice vibration bands, associated with (PO4)3− ions and water molecules. Meanwhile, thermogravimetric analysis and differential scanning calorimetry indicate water loss at around 187 °C. The thin film of Fe3(NH4)H8(PO4)6.6H2O is prepared by electrodeposition from Mohr's salt and phosphoric acid at 0.6 V/saturated calomel electrode. Analysis by scanning electron microscopy combined with energy dispersive X‐ray spectroscopy, X‐ray diffraction (XRD) , fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry confirms its morphology, hexagonal structure, purity and thermal properties. All these characteristics suggest that this material can be a promising candidate for a variety of applications.
Evaluation of Poorly Soluble Drugs’ Dissolution Rate by Laser Scattering in Different Water Isotopologues
The most important task in the design of dosage forms is to modify the pharmaceutical substances structure in order to increase solubilization, targeted delivery, controlled rate of drug administration, and its bioavailability. Screening—laboratory (in vitro) or computer (in silico)—as a procedure for selecting a prototype for the design of a drug molecule, involves several years of research and significant costs. Among a large number of solvents and diluents (alcohol, ether, oils, glycerol, Vaseline) used in the pharmaceutical industry for the manufacture of drugs water finds the greatest application. This is because all biological reactions (reactions in living systems) take place in water and distribution of the fluid in the body and the substances found within is critical for the maintenance of intracellular and extracellular functions. Modern studies in the field of the stable isotopic compositions of natural water and its structure and properties make it possible to use isotopic transformations of the water to improve the pharmacokinetic properties of medicinal substances without previous structural modification. It is known that by replacing any of the atoms in the reacting substance molecule with its isotope, it is possible to record changes in the reactivity, which are expressed as a change in the reaction rate constant, i.e., in the manifestation of the kinetic isotope effect (KIE). The article presents the results of studies on the effect of the kinetic isotope effect of a solvent—water—on increasing the solubility and dissolution rate constants of poorly soluble drugs using laser diffraction spectroscopy. The results of the studies can be successfully implemented in pharmaceutical practice to overcome the poor solubility of medicinal substances of classes II and IV, according to the biopharmaceutical classification system (BCS), in water for pharmaceutical purposes by performing its preliminary and safe isotopic modification.
In Situ Plasma Monitoring of PECVD nc-Si:H Films and the Influence of Dilution Ratio on Structural Evolution
We report plasma-enhanced chemical vapor deposition (PECVD) hydrogenated nano-crystalline silicon (nc-Si:H) thin films. In particular, the effect of hydrogen dilution ratio (R = H2/SiH4) on structural and optical evolutions of the deposited nc-Si:H films were systematically investigated including Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and low angle X-ray diffraction spectroscopy (XRD). Measurement results revealed that the nc-Si:H structural evolution, primarily the transition of nano-crystallization from the amorphous state to the nanocrystalline state, can be carefully induced by the adjustment of hydrogen dilution ratio (R). In addition, an in situ plasma diagnostic tool of optical emission spectroscopy (OES) was used to further characterize the crystallization rate index (Hα*/SiH*) that increases when hydrogen dilution ratio (R) rises, whereas the deposition rate decreases. Another in situ plasma diagnostic tool of quadruple mass spectrometry (QMS) also confirmed that the “optimal” range of hydrogen dilution ratio (R = 30–40) can yield nano-crystalline silicon (n-Si:H) growth due to the depletion of higher silane radicals. A good correlation between the plasma characteristics by in situ OES/QMS and the film characteristics by XRD, Raman and FTIR, for the transition of a-Si:H to nc-Si:H film from the hydrogen dilution ratio, was obtained.