170 research outputs found
Assessment of the quantitative accuracy of Rietveld/XRD analysis of crystalline and amorphous phases in fly ash
An internal standard method based on Rietveld/XRD whole-pattern fitting analysis of fly ash is used to assess
the quantitative accuracy to determine its crystalline and amorphous phases under various conditions such
as internal standards (types, SiO2 or Al2O3 and dosages, 10–50%), incident X-rays (laboratory or
synchrotron) and refinement software (GSAS or TOPAS). The results reveal that the quantitative stability is
quite sensible to minor phases, identical to the internal standard, in fly ash. Errors positively correlate
with the weight fraction of that minor phase and negatively correlate with the dosage of an internal
standard and amorphous phase content in fly ash. The original equation for the amorphous phase
calculation is not applicable for a case with a higher inherent quartz content (>2.5%) in fly ash while the
dosages of the internal standard is lower than 20%. The original equation is modified as proposed. Based
on it, the quantitative results of five different patterns report a good reproducibility with the arithmetic
mean errors and the standard errors of identified main phases of around 1%.The access to the beamline BL14B1 facilities at the SSRF is
appreciated and the support of SSRF management, User Office
and beamline staff is highly appreciated. This Research is
supported by the National Natural Science Foundation of China
(No. 51602126), the National Key Research and Development
Plan of China (2016YFB0303505) and the Program for Scientic
Research Innovation Team in Colleges and Universities of
Shandong Province
A Frequency Selective Surface based focal plane receiver for the OLIMPO balloon-borne telescope
We describe here a focal plane array of Cold-Electron Bolometer (CEB)
detectors integrated in a Frequency Selective Surface (FSS) for the 350 GHz
detection band of the OLIMPO balloon-borne telescope. In our architecture, the
two terminal CEB has been integrated in the periodic unit cell of the FSS
structure and is impedance matched to the embedding impedance seen by it and
provides a resonant interaction with the incident sub-mm radiation. The
detector array has been designed to operate in background noise limited
condition for incident powers of 20 pW to 80 pW, making it possible to use the
same pixel in both photometric and spectrometric configurations. We present
high frequency and dc simulations of our system, together with fabrication
details. The frequency response of the FSS array, optical response measurements
with hot/cold load in front of optical window and with variable temperature
black body source inside cryostat are presented. A comparison of the optical
response to the CEB model and estimations of Noise Equivalent power (NEP) is
also presented
NMR-Metabolic Methodology in the Study of GM Foods
The 1H-NMR methodology used in the study of genetically modified (GM) foods is discussed. Transgenic lettuce (Lactuca sativa cv "Luxor") over-expressing the ArabidopsisKNAT1 gene is presented as a case study. Twenty-two water-soluble metabolites (amino acids, organic acids, sugars) present in leaves of conventional and GM lettuce were monitored by NMR and quantified at two developmental stages. The NMR spectra did not reveal any difference in metabolite composition between the GM lettuce and the wild type counterpart. Statistical analyses of metabolite variables highlighted metabolism variation as a function of leaf development as well as the transgene. A main effect of the transgene was in altering sugar metabolism
Characterization of local products for their industrial use: the case of italian potato cultivars analyzed by untargeted and targeted methodologies
The chemical characterization of local Italian potato cultivars is reported to promote their preservation and use as high quality raw material in food industries. Twenty potato (Solanum tuberosum L.) cultivars from Piedmont and Liguria Italian regions were investigated using NMR (Nuclear Magnetic Resonance) and RP-HPLC-PDA-ESI-MSn (Reversed Phase High-Performance Liquid Chromatography with Photodiode Array Detector and Electrospray Ionization Mass Detector) methodologies. Water soluble and lipophilic metabolites were identified and quantified. With respect to literature data, a more complete 1H (protonic) spectral assignment of the aqueous potato extracts was reported, whereas the 1H NMR assignment of potato organic extracts was reported here for the first time. Phenolics resulted to be in high concentrations in the purple-blue colored Rouge des Flandres, Bergerac, Fleur Bleu, and Blue Star cultivars. Servane, Piatlina, and Malou showed the highest amount of galacturonic acid, a marker of pectin presence, whereas Jelly cultivar was characterized by high levels of monosaccharides. Roseval and Rubra Spes contained high levels of citric acid involved in the inhibition of the enzymatic browning in fresh-cut potato. High levels of the amino acids involved in the formation of pleasant-smell volatile compounds during potato cooking were detected in Rouge des Flandres, Blue Star, Bergerac, Roseval, and Ratte cultivars. These results suggest that each local cultivar is characterized by a proper chemical profile related to specific proprieties that can be useful to obtain high quality industrial products
The role of the Fe/Mo cations ordering degree and oxygen non-stoichiometry on the formation of the crystalline and magnetic structure of Sr2FeMoO6‒δ
Single-phase Sr2FeMoO6-δ powders with various oxygen indices (δ) and degrees of the superstructural ordering (P) of the Fe/Mo cations were obtained from SrFeO2.52 and SrMoO4 reagents via solid-state synthesis. It has been established by means of the x-ray and neutron diffraction that, upon reducing the oxygen content and enhancing the superstructural ordering, the lengths of the Fe–O1 and Mo–O2 bonds in the crystal lattice increase, whereas the Fe–O2 and Mo–O1 bond lengths decrease. At the same time, the volume of the unit cell is reduced, which indicates an enhancement of the covalency degree of the bonds and stimulates a redistribution of the electron density, as well as an increase of the concentration of the spin-down charge carriers located in the conduction band on the Mo(t2g)↓ orbitals. This circumstance leads to an increase of the density of states at the Fermi level, accompanied by an amplification of the exchange interaction and elevation of the Curie temperature, which points to the leading role of the spin-polarized charge carriers at the Fermi level in the exchange interaction.publishe
Small-angle neutron scattering and magnetically heterogeneous state in Sr2FeMoO6–δ
Single-phase strontium ferromolybdate (Sr2FeMoO6–δ) samples with different degrees of the superstructural ordering of the Fe/Mo cations were obtained from partially reduced SrFeO3–х, SrMoO4 precursors by the solid-state technology. The study of the temperature dependences of the magnetization measured in the field-cooling and zero-field-cooling regimes indicated an inhomogeneous magnetic state of the samples. The presence of magnetic regions of different nature has also been revealed by the small-angle neutron scattering. For the Sr2FeMoO6–δ samples with different superstructural ordering of the Fe/Mo cations and for all values of the magnetic field induction in the range up to 1.5 T and of the scattering vector in the interval 0.1 >q >0.005 Å–1, the analytical dependence I ~ q–α obeys the Porod law (α ≈ 4), which corresponds to an object with a smooth and well-marked surface and polydisperse grain size. Deviations from the Porod law in the q > 0.1 Å–1 region and a weakening of the neutron scattering in applied magnetic fields may be ascribed to magnetic inhomogeneities with diameters D <6 nm, which are partially destroyed /oriented by magnetic fields В ≥1.5 T.publishe
Re-Os isotope and platinum group elements of a FOcal ZOne mantle source, Louisville Seamounts Chain, Pacific ocean
The Louisville Seamount Chain (LSC) is, besides the Hawaiian-Emperor Chain, one of the longest-lived hotspot traces. We report here the first Re-Os isotope and platinum group element (PGE) data for Canopus, Rigil, and Burton Guyots along the chain, which were drilled during IODP Expedition 330. The LSC basalts possess (187Os/188Os)i = 0.1245–0.1314 that are remarkably homogeneous and do not vary with age. A Re-Os isochron age of 64.9 ± 3.2 Ma was obtained for Burton seamount (the youngest of the three seamounts drilled), consistent with 40Ar-39Ar data. Isochron-derived initial 187Os/188Os ratio of 0.1272 ± 0.0008, together with data for olivines (0.1271–0.1275), are within the estimated primitive mantle values. This (187Os/188Os)i range is similar to those of Rarotonga (0.124–0.139) and Samoan shield (0.1276–0.1313) basalts and lower than those of Cook-Austral (0.136–0.155) and Hawaiian shield (0.1283–0.1578) basalts, suggesting little or no recycled component in the LSC mantle source. The PGE data of LSC basalts are distinct from those of oceanic lower crust. Variation in PGE patterns can be largely explained by different low degrees of melting under sulfide-saturated conditions of the same relatively fertile mantle source, consistent with their primitive mantle-like Os and primordial Ne isotope signatures. The PGE patterns and the low 187Os/188Os composition of LSC basalts contrast with those of Ontong Java Plateau (OJP) tholeiites. We conclude that the Re-Os isotope and PGE composition of LSC basalts reflect a relatively pure deep-sourced common mantle sampled by some ocean island basalts but is not discernible in the composition of OJP tholeiites
Commercial hemp seed oils: a multimethodological characterization
Nine commercial hemp seed oils from different countries were studied using a multimethodological approach to obtain information about their quality and chemical composition. Due to the lack of a specific regulation for hemp seed oils, quality parameters used in the case of olive oils (free acidity, peroxides number, spectrophotometer parameters) and anisidine number were measured and compared with those reported for extra virgin olive oil (EVOO). Free acidity and peroxides number showed a great variability, ranging from 0.4 to 17.24% and from 4.32 to 22.14 meqO2/kg, respectively, whereas the anisidine number ranged from 0.11 to 3.58. K232 value turned out to be generally below the limit reported for EVOO, whereas K270 and ΔK values were higher, with respect to EVOO limits, due to the high amount of tri-unsaturated fatty chains. Colorimetric analysis showed a peculiar curve trend that could represent the fingerprint of this product. Untargeted nuclear magnetic resonance methodology allowed to measure the amount of fatty chains, ω-6:ω-3 ratio, β-sitosterol, and aldehydes. The ω-6:ω-3 ratio turned out to be, in some cases, different from that reported on the bottle labels. Finally, lipoperoxidation assays were also carried out under different storage (light and temperature) and time exposure conditions, confirming that the exposure to direct light is the condition that interferes more with the product quality
The Victorian Newsletter (Fall 2000)
The Victorian Newsletter is sponsored for the Victorian Group of the Modern Language Association by Western Kentucky University and is published twice annually.Selecting Heroines: George Gissing and "Sexual Science" / Rosemary Jann -- An Annotated Secondary Bibliography: The Picture of Dorian Gray (1980-1999) / Valentina Di Pietro -- Hopkins, Language, Meaning / Dennis Sobolev -- Benjamin Disraeli's The Young Duke and the Condition of England's Aristocrats / Maria K. Bachmann -- A Victorian Sensation Novel in the "Contact Zone" : Reading Lady Audley's Secret through Imperial Eyes / R. Mark Hall -- Burying the Dead: Matthew Arnold and the Dissenters / Terry G. Harris -- Coming in The Victorian Newsletter -- Books Received -- Group New
Chemico-biological characterization of Torpedino Di Fondi® tomato fruits. A comparison with San Marzano cultivar at two ripeness stages
Torpedino di Fondi (TF) is a hybrid tomato landrace developed in Sicily and recently introduced in the south Lazio area along with the classical San Marzano (SM) cultivar. The present study aimed at characterizing TF tomatoes at both pink and red ripening stages, and at comparing them with traditional SM tomatoes. A multidisciplinary approach consisting of morphological, chemical (FT‐ICR MS, NMR, HPLC, and spectrophotometric methods), and biological (antioxidant and antifungal in vitro activity) analyses was applied. Morphological analysis confirmed the mini‐ San Marzano nature and the peculiar crunchy and solid consistency of TF fruits. Pink TF tomatoes displayed the highest content of hydrophilic antioxidants, like total polyphenols (0.192 mg/g), tannins (0.013 mg/g), flavonoids (0.204 mg/g), and chlorophylls a (0.344 mg/g) and b (0.161 mg/g), whereas red TF fruits were characterized by the highest levels of fructose (3000 mg/100 g), glucose (2000 mg/100 g), tryptophan (2.7 mg/100 g), phenylalanine (13 mg/100 g), alanine (25 mg/100 g), and total tri‐unsaturated fatty acids (13% mol). Red SM fruits revealed the greatest content of lipophilic antioxidants, with 1234 mg/g of total carotenoids. In agreement with phenolics content, TF cultivar showed the greatest antioxidant activity. Lastly, red TF inhibited Candida species (albicans, glabrata
and krusei) growth
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