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Author(s):  
Konan N’dri Séraphin ◽  
Yéo Sounta ◽  
Angbeé Kassé Jean-Hugues ◽  
Kouamé Bosson Antoine ◽  
MamyrBékova-Békro Janat Akhanovna ◽  
...  

Aims: The objective of this work is to contribute to the valorization of medicinal and aromatic plants of the Ivorian flora. We propose to determine the chemical composition and to evaluate the antioxidant activity by spectrophotometry of the essential oil of Cardiospermum. grandiflorum Sw Study Design: Valorization of aromatic and medicinal plants. Methodology: The technical of steam distillation using a four-compartment stainless steel device was used to extract the essential oil from the plant matrix. The analysis of the essential oils was carried out on a GC chromatograph (7890A, Agilent Technologies) coupled to a mass spectrometer (5975C, Agilent Technologies). The identification of the compounds was carried out by comparison of the retention indices and mass spectra obtained with those from the National Institute of Standards and Technology (NIST) database and from the literature The antioxidant potential of the extracts was evaluated using the Blois method. Results: The essential oil obtained by steaming, with an aromatic odor and pale yellow color has a yield of (0.0045 ± 0.0002)%. Analysis of the chromatogram and mass spectra obtained by GC-MS identified 24 phytocompounds representing 99.45% of the total chemical composition. The chemical composition of EO consists mainly of hydrocarbon sesquiterpenes (97.72%).The major compound is γ-muurolene (46.06%) (A) followed by β-Caryophyllene (24.35%) (B) and γ-elemene (7.07 %). The essential oil extract of C. grandiflorum exhibits low antioxidant activity compared to vitamin C. The IC 50 value of vitamin C is 0.31 µg / mL while that of EO extract of C grandiflorum is 15.1 µg / mL Conclusion: In the present study, we are interested in the valuation of Cardiospermum grandiflorum an aromatic plant used in traditional Ivorian medicine. The yields of essential oil is low.  (24) phytocompounds were identified there. The essential oil has less antioxidant activity than that of vitamin C,


Informatics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 86
Author(s):  
Ioannis Tsantilis ◽  
Thomas K. Dasaklis ◽  
Christos Douligeris ◽  
Constantinos Patsakis

Cybersecurity is a never-ending battle against attackers, who try to identify and exploit misconfigurations and software vulnerabilities before being patched. In this ongoing conflict, it is important to analyse the properties of the vulnerability time series to understand when information systems are more vulnerable. We study computer systems’ software vulnerabilities and probe the relevant National Vulnerability Database (NVD) time-series properties. More specifically, we show through an extensive experimental study based on the National Institute of Standards and Technology (NIST) database that the relevant systems software time series present significant chaotic properties. Moreover, by defining some systems based on open and closed source software, we compare their chaotic properties resulting in statistical conclusions. The contribution of this novel study is focused on the prepossessing stage of vulnerabilities time series forecasting. The strong evidence of their chaotic properties as derived by this research effort could lead to a deeper analysis to provide additional tools to their forecasting process.


Author(s):  
Weihua Liu ◽  
Jianxiang Tian ◽  
Shangguo Yang

We collected data of the surface tension versus the temperature of 28 saturated refrigerant fluids available in the NIST database. These data are used to build a new corresponding state-based correlation. Compared with other previously proposed correlations, the current one has the advantages of both simplicity and accuracy. To check the ability of correlations, we compared the numerically calculated/predicted results with the data in the NIST database. It is found that the average absolute deviations are less than 10% for 26 refrigerants and less than 1% for 8 refrigerants.


2021 ◽  
Vol 257 (2) ◽  
pp. 29
Author(s):  
Laima Radžiūtė ◽  
Gediminas Gaigalas ◽  
Daiji Kato ◽  
Pavel Rynkun ◽  
Masaomi Tanaka

Abstract In this work, we continue large-scale ab initio computations for single ionized lanthanides. Extended atomic calculations for the set of ions from Pr ii (Z = 59) to Gd ii (Z = 64) have been performed in our previous work. In this study, ions from Tb ii (Z = 65) to Yb ii (Z = 70) are analyzed. By employing the same multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction methods that are implemented in the general-purpose relativistic atomic structure package GRASP2018, the energy levels and transition data of electric dipole (E1) transitions are computed. These computations are based on the strategies (with small variations) of Paper I. Accuracy of data is evaluated by comparing the computed energy levels with the data provided by the National Institute of Standards and Technology (NIST) database and with data from various methods. We obtain the average accuracy in the energy level compared with the NIST database: 6%, 5%, 4%, 5%, 3%, and 3% for Tb ii, Dy ii, Ho ii, Er ii, Tm ii, and Yb ii, respectively. We also provide extensive comparison of transition probabilities and wavelengths. Our results reach the average accuracy of transition wavelengths: 9%, 9%, 9%, 3%, 4%, and 11% for Tb ii, Dy ii, Ho ii, Er ii, Tm ii, and Yb ii, respectively.


2021 ◽  
Vol 15 (5) ◽  
pp. 693-699
Author(s):  
Lulu Geng ◽  
Min Wang ◽  
Mingshi Liu ◽  
Haoyang Sun

In this paper, a novel approach was set up to analyze and discriminate propolis from different regions based on GC-MS and multivariate statistical analysis. A number of Chinese and Brazilian green propolis samples were dealt with based on this method, and a set of data were processed with partial least squares-discriminant analysis (PLS-DA). A clear differences between the two groups were shown in score plot. The chemical markers for the differentiation were selected through loading plot. Based on the comparison between the reference and/or NIST database and mass fragments in the publication, chemical markers were tentatively identified. Lauric acid, 2(3H)-naphthalenone, spathulenol and benzenebutanoic acid were taken as chemical markers based on the above strategy. This research could provide some valuable information to the quality control of propolis from different origins.


Author(s):  
Zhigang LI ◽  
Zhuocong Li ◽  
Jun Li ◽  
Zhenping Feng

Abstract This paper presents a comprehensive assessment and comparison on the leakage and rotordynamic performance of three types of annular gas seals for application in a 14 MW supercritical CO2 turbine. These three seals represent the main seal types used in high-speed rotating machines at the balance piston location in efforts to limit internal leakage flow and achieve rotordynamic stability, including a labyrinth seal (LABY), a fully-partitioned pocket damper seal (FPDS), and a hole-pattern seal (HPS). These three seals were designed to have the same sealing clearance and similar axial lengths. To enhance the seal net damping capability at high inlet preswirl condition, a straight swirl brake also was designed and employed at seal entrance for each type seal to reduce the seal inlet pre-swirl velocity. Numerical results of leakage flow rates, rotordynamic force coefficients, cavity dynamic pressure and swirl velocity developments were analyzed and compared for three seal designs at high positive inlet preswirl (in the direction of shaft rotation), using a proposed transient CFD-based perturbation method based on the multiple-frequency elliptical-orbit rotor whirling model and the mesh deformation technique. To take into account of real gas effect with high accuracy, a table look-up procedure based on the NIST database was implemented, using an in-house code, for the fluid properties of CO2 in both supercritical and subcritical conditions.


Author(s):  
Savka Adamović ◽  
◽  
Ivan Pinćjer ◽  
Bojan Banjanin ◽  
Stefan Đurđević ◽  
...  

The validation of the extraction method is significant for the characterization of the offset effluent and the selection of an adequate effluent treatment for its safe disposal in a printing environment. For the aforementioned reasons, the qualitative characterization of the organic load profile of the waste offset developer was evaluated based on the application of two liquid/liquid (L/L) extraction methods. The gas chromatographic/mass spectrometric (GC/MS) method was used for the qualitative detection of the organic compounds present in the offset effluent. The cumulative qualitative GC/MS profile of organic substances in the waste offset developer indicates that the effluent contains 69 organic compounds with a probability of presence higher than 70% according to the AMDIS software and the NIST database.


Atoms ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Kin-Fung Lai ◽  
Wim Ubachs ◽  
Nelson De Oliveira ◽  
Edcel J. Salumbides

Accurate Fourier-transform spectroscopic absorption measurements of vacuum ultraviolet transitions in atomic nitrogen and carbon were performed at the Soleil synchrotron. For 14N, transitions from the 2s22p34S3/2 ground state and from the 2s22p32P and 2D metastable states were determined in the 95–124 nm range at an accuracy of 0.025cm−1. The combination of these results with data from previous precision laser experiments in the vacuum ultraviolet range reveals an overall and consistent offset of −0.04 cm−1 from values reported in the NIST database. The splittings of the 2s22p34S3/2 – 2s2p44PJ transitions are well-resolved for 14N and 15N and the isotope shifts determined. While excitation of a 2p valence electron yields very small isotope shifts, excitation of a 2s core electron results in large isotope shifts, in agreement with theoretical predictions. For carbon, six transitions from the ground 2s22p23PJ and 2s22p3s3PJ excited states at 165 nm are measured for both 12C and 13C isotopes.


Atoms ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 52
Author(s):  
Nicholas L. Wong ◽  
Fergal O’Reilly ◽  
Emma Sokell

Plasmas of a variety of types can be described by the collisional radiative (CR) model developed by Colombant and Tonan. From the CR model, the ion distribution of a plasma at a given electron temperature and density can be found. This information is useful for further simulations, and due to this, the employment of a suitable CR model is important. Specifically, ionization bottlenecks, where there are enhanced populations of certain charge states, can be seen in these ion distributions, which in some applications are important in maintaining large amounts of a specific ion. The present work was done by implementing an accepted CR model, proposed by Colombant and Tonon, in Python and investigating the effects of variations in the ionization energy and outermost electron subshell occupancy term on the positions of ionization bottlenecks. Laser Produced Plasmas created using a Nd:YAG laser with an electron density of ∼ne = 1021 cm−3 were the focus of this work. Plots of the collisional ionization, radiative recombination, and three-body recombination rate coefficients as well as the ion distribution and peak fractional ion population for various elements were examined. From these results, it is evident that using ionization energies from the NIST database and removing the orbital occupancy term in the CR model produced results with ionization bottlenecks in expected locations.


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