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  • Artikel  (5)
  • Environmental sensing
  • Impedance spectroscopy
  • Lipids
  • Microspectroscopy Analysis
  • American Chemical Society  (3)
  • Lagos  (2)
  • Periodicals Archive Online (PAO)
  • 1
    Publikationsdatum: 2017-04-04
    Beschreibung: Red Pompeian paintings, very famous for their deep intensity, are currently suffering from darkening. The origins of this darkening degradation are not clearly identified yet and remain a major issue for curators. In the specific case of cinnabar (HgS)-based red pigment, a photoinduced conversion into black metacinnabar is usually suspected. This work is focused on the blackening of red cinnabar paintings coated on a sparry calcite mortar. Different samples exhibiting different levels of degradation were selected upon visual observations and analyzed by synchrotron-based microanalytical techniques. Atomic and molecular compositions of the different debased regions revealed two possible degradation mechanisms. On one hand, micro X-ray fluorescence elemental maps show peculiar distributions of chlorine and sulfur. On the other hand, X-ray absorption spectroscopy performed at both Cl and S K-edges confirms the presence of characteristic degradation products: (i) Hg- Cl compounds (e.g., corderoite, calomel, and terlinguaite), which may result from the reaction with exogenous NaCl, in gray areas; (ii) gypsum, produced by the calcite sulfation, in black coatings. Metacinnabar is never detected. Finally, a cross section was analyzed to map the in-depth alteration gradient. Reduced and oxidized sulfur distributions reveal that the sulfated black coating consists of a 5-ím-thick layer covering intact cinnabar.
    Beschreibung: Published
    Beschreibung: 7484-7492
    Beschreibung: reserved
    Schlagwort(e): Microspectroscopy Analysis ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
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    Unbekannt
    Fisheries Society of Nigeria | Lagos
    In:  http://aquaticcommons.org/id/eprint/23016 | 19325 | 2018-03-05 20:27:12 | 23016 | Fisheries Society of Nigeria
    Publikationsdatum: 2021-07-12
    Beschreibung: A study was carried out to examine the effect of lipid level on growth and feed utilization of Heterobranchus longifilis. Fingerlings of H. longifilis (28 days old (0.7 ~c 0.05g) were fed three formulated diets with three levels of lipid (7.00%, 12.5% and 18.0% of dry matter) at one level of protein (35.0% crude protein dry matter (OM) basis) for eight weeks. Weight gain (g) and specific growth rate (SGR, % day-1) values indicated that fish fed diets with 7.0% and 12.5% lipid exhibited higher growth performance. Lowest growth was recorded for fish fed diet with 18.0% lipid. Feed intake (FI, g fish-1) was also significantly (P 〈 0.05) affected by dietary lipids and tended to decrease with increasing lipid levels. Fish that showed the highest FI were those that were fed the 7% and 12.5% lipid diets. Feed conversion ratio (FCR) values indicated that diets containing 12.5% and 18% lipid were more efficiently utilized. No significant differences in muscle composition were observed among fish fed the different diets. There was a linear relationship (P〈0.05) between dietary lipid level and liver lipid. Hepatosomatic index (HIS) increased with dietary lipid level. The results indicated that H. longifilis fingerlings performed best with the diets containing 7.0% and 12.5% lipid when protein concentration was 35.0% and, reduced growth and increased body fat were evident when dietary energy increased from 19.06 to 20.54 kJg-1.
    Beschreibung: Includes:- 3 tables.;35 refs.
    Schlagwort(e): Aquaculture ; Heterobranchus longifilis ; Nigeria ; Feed Utilization ; freshwater environment ; Fish culture ; Lipids ; Growth ; Feed efficiency ; Feeding experiments
    Repository-Name: AquaDocs
    Materialart: conference_item , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 193 - 199
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    facet.materialart.
    Unbekannt
    Fisheries Society of Nigeria | Lagos
    In:  http://aquaticcommons.org/id/eprint/23059 | 19325 | 2018-03-06 15:38:43 | 23059 | Fisheries Society of Nigeria
    Publikationsdatum: 2021-07-12
    Beschreibung: The proximate composition of the fresh water shrimp Atya gabonensis (Irvine), preserved by smoking, salting and sun - drying was determined and compared to the fresh shrimp. All the preservation methods significantly (p〈 0.05) increased the total dry matter (38.34 93%), protein content (17.31 48.9) and ash content (28.36 36.17%) over the fresh shrimp value. Moisture and lipid contents however, were reduced from the fresh shrimp's 61.66% and 25.29% to low value of 7.00% and 5.10% respectively. The preserved shrimp is, therefore, nutritionally superior to the fresh shrimp as preservation enhances its proximate composition. Of all the preservation methods used in this work, smoking is the best. It recorded the best preservation indices of lowest moisture content, higher dry matter, higher protein content and highest ash content.
    Beschreibung: Includes:- 1 table.;13 refs.
    Schlagwort(e): Fisheries ; Chemistry ; Atya gabonensis ; Nigeria ; Benue R. ; freshwater environment ; Lipids ; Organic compounds ; Proteins ; Ash content ; Cured products ; Fish ; Shrimp fisheries
    Repository-Name: AquaDocs
    Materialart: conference_item , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 378 -381
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Publikationsdatum: 2022-05-27
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gosselin, K. M., Nelson, R. K., Spivak, A. C., Sylva, S. P., Van Mooy, B. A. S., Aeppli, C., Sharpless, C. M., O’Neil, G. W., Arrington, E. C., Reddy, C. M., & Valentine, D. L. Production of two highly abundant 2-methyl-branched fatty acids by blooms of the globally significant marine cyanobacteria Trichodesmium erythraeum. ACS Omega, 6(35), (2021): 22803–22810, https://doi.org/10.1021/acsomega.1c03196.
    Beschreibung: The bloom-forming cyanobacteria Trichodesmium contribute up to 30% to the total fixed nitrogen in the global oceans and thereby drive substantial productivity. On an expedition in the Gulf of Mexico, we observed and sampled surface slicks, some of which included dense blooms of Trichodesmium erythraeum. These bloom samples contained abundant and atypical free fatty acids, identified here as 2-methyldecanoic acid and 2-methyldodecanoic acid. The high abundance and unusual branching pattern of these compounds suggest that they may play a specific role in this globally important organism.
    Beschreibung: This work was funded with grants from the National Science Foundation grants OCE-1333148, OCE-1333162, and OCE-1756254 and the Woods Hole Oceanographic Institution (IR&D). GCxGC analysis made possible by WHOI’s Investment in Science Fund.
    Schlagwort(e): Lipids ; Alkyls ; Bacteria ; Genetics ; Chromatography
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Publikationsdatum: 2022-10-21
    Beschreibung: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Colson, B. C., & Michel, A. P. M. Flow-through quantification of microplastics using impedance spectroscopy. ACS Sensors, 6(1), (2021): 238–244, doi:10.1021/acssensors.0c02223.
    Beschreibung: Understanding the sources, impacts, and fate of microplastics in the environment is critical for assessing the potential risks of these anthropogenic particles. However, our ability to quantify and identify microplastics in aquatic ecosystems is limited by the lack of rapid techniques that do not require visual sorting or preprocessing. Here, we demonstrate the use of impedance spectroscopy for high-throughput flow-through microplastic quantification, with the goal of rapid measurement of microplastic concentration and size. Impedance spectroscopy characterizes the electrical properties of individual particles directly in the flow of water, allowing for simultaneous sizing and material identification. To demonstrate the technique, spike and recovery experiments were conducted in tap water with 212–1000 μm polyethylene beads in six size ranges and a variety of similarly sized biological materials. Microplastics were reliably detected, sized, and differentiated from biological materials via their electrical properties at an average flow rate of 103 ± 8 mL/min. The recovery rate was ≥90% for microplastics in the 300–1000 μm size range, and the false positive rate for the misidentification of the biological material as plastic was 1%. Impedance spectroscopy allowed for the identification of microplastics directly in water without visual sorting or filtration, demonstrating its use for flow-through sensing.
    Beschreibung: The authors thank the Richard Saltonstall Charitable Foundation and the National Academies Keck Futures Initiative (NAKFI DBS13) for their funding support.
    Schlagwort(e): Microplastics ; Plastics ; Impedance spectroscopy ; Dielectric properties ; Instrumentation ; Particle detection ; Flow-through ; Environmental sensing
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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