Search results for "STANDARD"
showing 10 items of 3299 documents
Flow injection-FTIR determination of dithiocarbamate pesticides
2000
A flow injection Fourier transform infrared spectrometric procedure has been developed for the determination the dithiocarbamate pesticides Ziram and Thiram in solid samples. All the operations involved, such as extraction, filtration and measurement, were integrated in the experimental set-up in order to avoid excessive manipulation of samples and standards. Ultrasonic assisted and mechanical extraction were evaluated for the solubilization of the analytes and, additionally, the effect of carrier flow rate, sample loop volume and the ratio between sample mass and volume of solvent employed were studied. Quantitative extractions with chloroform were obtained for both Ziram and Thiram, after…
Determination of insolubles in diesel lubricating oil by FIA-visible spectrometry
2003
Insolubles determination is one of the parameters usually recommended to evaluate the residual life of oil because their presence at elevated levels in diesel lubricating oil changes the viscosity, prematurely clogs filters and is one of the major factors in causing abrasive engine wear. The proposed method employs visible spectrophotometric detection in association with flow injection analysis. The results obtained by this method were compared with the ones obtained by Fourier transform infrared spectrometry (FT-IR) since this is the most employed method for insolubles determination. The proposed method presented a linear response from 0 to 3% (w/w) of insolubles in pentane (ASTM D-893). T…
Nexus Water & Energy: A Case Study of Wave Energy Converters (WECs) to Desalination Applications in Sicily
2016
The recent studies about interactions among energy and water are considered as a new field of research. As almost all energy generation processes require significant amounts of water, and water requires energy for treatment and transport, so these two resources are inextricably linked. The main aim of this work is a presentation of the use of renewable energy for desalination plants in Sicily: in particular exploitation of wave energy into electrical energy necessary for water treatment. Desalination is the most energy intensive water treatment technology but it could be solution for many problems in water supply for areas with chronic debt of water. In this study we find three section: in …
Evaluation of the interelemental effect in X-ray fluorescence analysis by the total addition method
1992
An algorithm for quantifying interelemental effects in X-ray fluorescence techniques is developed. By applying an addition process, the ratio between the mass absorption coefficients of the analyte and the unknown sample (μi*/μs*) is calculated to correct the fluorescence intensity of the element to be determined and linearize the I-c calibration plot. This coefficient can be calculated graphically and numerically. The method is applied to the determination of tin in lead alloys with good results over wide concentration ranges.
Evaluation of P-glycoprotein (abcb1a/b) modulation of [18F]fallypride in MicroPET imaging studies
2012
[(18)F]Fallypride ([(18)F]FP) is an important and routinely used D2/D3 antagonist for quantitative imaging of dopaminergic neurotransmission in vivo. Recently it was shown that the brain uptake of the structurally related [(11)C]raclopride is modulated by P-glycoprotein (P-gp), an important efflux transporter at the blood-brain barrier. The purpose of this study was to determine whether the brain uptake of [(18)F]FP is influenced by P-gp. For examination of this possible modulation microPET studies were performed in a rat and a mouse model. Hence, [(18)F]FP was applied to Sprague Dawley rats, half of them being treated with the P-gp inhibitor cyclosporine A (CsA). In a second experimental s…
ISO 14470:2011 and EU legislative background on food irradiation technology: The Italian attitude
2014
Our work aim is to produce an overview of food irradiation technology at European Union level, with a focus on the Italian context, by specifying the legislative background, detection methods and labelling obligations. We highlight how consumers are too often misinformed about this technology and its benefits. For this purpose, a series of tools aimed at improving the amount of information have been proposed, allowing the consumer to make a free choice about whether or not to buy irradiated food based on the correct information received, independent from socio-economic factors. Finally, we show the common effort at EU and International level, represented by the ISO 14470:2011 quality standa…
Forest types for biodiversity assessment at regional level: the case study of Sicily (Italy)
2007
Within Europe the question of plant coenosis is attracting growing interest. The quality and quantity of collected information on forest resources at a global level largely depends on the capacity to collect and analyse data at national and sub-national scale in a way compatible with those at global or continental levels. In Italy the acceptance of all the international agreements and protocols on the protection of the environment and management of natural resources, requires a standardization of collected information and statistics, with the aim to produce homogeneous and integrative data at global level. This need is reflected in the following points: (1) the adoption of a classification …
After the Press Release on Mathematics Achievement : The Alignment of Formative Assessments and Summative Standardized Tests for Students from Minori…
2018
Media coverage often reports standardized test scores as indicative of global competitiveness and journalists frequently frame the mathematics achievement of U.S. students using a discourse of failure, particularly for students from minoritized backgrounds. Informed by research literature on: (a) formative and summative assessment, (b) the interdependence of language and mathematics, and (c) a sociopolitical stance for researching students from minoritized language backgrounds, this study analyzed the linguistic alignment of mathematics assessments. Results from this study show how alignment between formative assessment processes and summative standardized tests influences performance on hi…
On the numerical implementation of a 3D fractional viscoelastic constitutive model
2015
The aim of this paper is the implementation of a 3D fraction al viscoelastic constitutive law in a user material subroutine (UMAT) in the finite element software Abaqus. Essential to the implementation of the model is access to the strain history at each Gauss point of each element in a constructive manner. Details of the UMAT and comparison with some analytical results are presented in order to show that the fractional viscoelastic constitutive law has been successfully implemented.
Redox potentials and acidity constants from density functional theory based molecular dynamics.
2014
CONSPECTUS: All-atom methods treat solute and solvent at the same level of electronic structure theory and statistical mechanics. All-atom computation of acidity constants (pKa) and redox potentials is still a challenge. In this Account, we review such a method combining density functional theory based molecular dynamics (DFTMD) and free energy perturbation (FEP) methods. The key computational tool is a FEP based method for reversible insertion of a proton or electron in a periodic DFTMD model system. The free energy of insertion (work function) is computed by thermodynamic integration of vertical energy gaps obtained from total energy differences. The problem of the loss of a physical refe…