Search results for "DRY"
showing 10 items of 980 documents
Dielectric and mechanical assessment of cellulosic insulation during transformer manufacturing
2021
Due to the impact of cellulose of paper insulation on transformer life, it is imperatire to remove moisture from the oil and the solid insulation. Several techniques have been implemented during manufacturing of power transformers to reduce water content in transformers. These drying processes can involve different costs and time, and they can damage the insulation paper. In this work, a drying process has been implemented in the laboratory trying to simulate the most aggressive conditions that can be suffered by the paper in transformer manufacturing in a real industry. Once the moisture content of papers was lower than 0.5%, the effect of the drying process on paper degradation was evalua…
Identification of lipid binders in old oil paintings by separation of 4-bromomethyl-7-methoxycoumarin derivatives of fatty acids by liquid chromatogr…
2005
A HPLC-fluorescence method for identification of drying oils from binding media or protective film used in pictorial works of art prior to conservation or restoration is proposed. Fluorescence derivatization of fatty acids released by hydrolysis of structural drying oils is studied. The derivatization reagent was 4-(bromomethyl)-7-methoxycoumarin with 18-crown-6 as catalyst. Mobile phase was programmed from methanol-water (90:10 v/v) to methanol-water (100:0 v/v) in 25 min. The excitation and emission wavelengths were 325 and 395 nm, respectively. Under these chromatographic conditions, coumarin derivatives of myristic, palmitic, oleic and stearic acids were satisfactorily resolved. The met…
Comparison of different methods for extraction of polycyclic aromatic hydrocarbons (PAHs) from Sicilian (Italy) coastal area sediments.
2012
This paper describes a work aimed at improving the conditions of an extraction method, coupling GC-MS determination, for the analysis without cleanup phase, of polycyclic aromatic hydrocarbons (PAHs) from sediment samples. The automatic Soxhlet extraction in warm mode (using Extraction System B-811 Standard, Buchi) has demonstrated advantages for automation, reduced extraction time, and lower solvent use than for conventional Soxhlet extraction. Under these conditions, the recoveries are very good as they resulted greater than 85 % and, in most of the cases, near 100 %. The repeatability is also satisfactory (relative standard deviation less than 15 %). The detection limits are also accepta…
Non-chromatographic speciation of mercury in mushrooms
2016
A fast, sensitive and cheap procedure has been developed for the determination of inorganic mercury (i-Hg) and organic mercury (o-Hg) in mushroom samples. The procedure is based on the use of cold vapour atomic fluorescence spectrometry (CV-AFS). The method involves the extraction of total mercury (t-Hg) with diluted HCl, followed by measurements of the corresponding Hg vapour under two different conditions: (i) directly to determine i-Hg, and (ii) after oxidation with a mixture KBr/KBrO3 to determine t-Hg. o-Hg was estimated from the difference between t-Hg and i-Hg. Previous studies were focused on the assessment of different reagents for mercury extraction and breakdown of organomercury …
Encapsulation of Alcohol Dehydrogenase in Mannitol by Spray Drying
2014
The retention of the enzyme activity of alcohol dehydrogenase (ADH) has been studied in various drying processes such as spray drying. The aim of this study is to encapsulate ADH in mannitol, either with or without additive in order to limit the thermal denaturation of the enzyme during the drying process. The retention of ADH activity was investigated at different drying temperatures. When mannitol was used, the encapsulated ADH was found inactive in all the dried powders. This is presumably due to the quick crystallization of mannitol during spray drying that resulted in the impairment of enzyme protection ability in comparison to its amorphous form. Maltodextin (dextrose equivalent = 11)…
Chirality and electronic structure of the thiolate-protected Au38 nanocluster.
2010
Structural, electronic, and optical properties of the thiolate-protected Au(38)(SR)(24) cluster are studied by density-functional theory computations (R = CH(3) and R = C(6)H(13)) and by powder X-ray crystallography (R = C(12)H(25)). A low-energy structure which can be written as Au(23)@(Au(SR)(2))(3)(Au(2)(SR)(3))(6) having a bi-icosahedral core and a chiral arrangement of the protecting gold-thiolate Au(x)(SR)(y) units yields an excellent match between the computed (for R = C(6)H(13)) and measured (for R = C(12)H(25)) powder X-ray diffraction function. We interpret in detail the electronic structure of the Au(23) core by using a particle-in-a-cylinder model. Although the alkane thiolate l…
Old World Megadroughts and Pluvials During the Common Era
2015
An atlas of megadroughts in Europe and in the Mediterranean Basin during the Common Era provides insights into climate variability.
Multi-residue determination of 47 organic compounds in water, soil, sediment and fish—Turia River as case study
2017
A sensitive and reliable method based on solid-liquid extraction (SLE) using McIlvaine-Na2EDTA buffer (pH = 4.5)-methanol and solid-phase extraction (SPE) clean up prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC–MS/MS) was applied to determine 47 organic contaminants in fish, soil and sediments. The SPE procedure to clean-up the extracts was also used as extraction method to determine these compounds in water. Recoveries ranged from 38 to 104% for all matrices with RSDs 50% for 36 compounds in front of 9, matrix effect < 20% for 31 compounds against 21, and LOQs <25 ng g−1 for 38 compounds against 22) indicates that the proposed method is mor…
Pre-stressed translucent panels made of innovative 3D glass components DSC-integrated, for safety and active building façades
2018
The widespread use of glazed envelopes, especially in high-rise buildings, is pushing building designers and researchers to the development of novel solutions for the improvement of their performance. At the University of Palermo, SBskin. Smart Building Skin s.r.l. (an innovative start up and academic spin off) is prototyping precast, pre- stressed and dry-assembled panels made of 3D glass subcomponents, able to reduce the energy consumption of buildings, to produce clean energy and to maintain high level of mechanical resistance against horizontal forces due to winds and earthquakes. The integration of glass subcomponents with third-generation PV technologies -Dye- Sensitized Solar Cells (…