Search results for " monitoring"

Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

2020

Abstract We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero‐field nuclear magnetic resonance spectroscopy. This is possible because magnetic susceptibility broadening is negligible at ultralow magnetic fields. We show the two‐step hydrogenation of dimethyl acetylenedicarboxylate with para‐enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero‐field NMR signals ensure that there is no significant signal attenuation arising from shielding by the electrically conductive sample container. This method paves the way for in situ monitoring of reactions in complex heteroge…

The Ramsey method in high-precision mass spectrometry with Penning traps: Experimental results

2007

The highest precision in direct mass measurements is obtained with Penning trap mass spectrometry. Most experiments use the interconversion of the magnetron and cyclotron motional modes of the stored ion due to excitation by external radiofrequency-quadrupole fields. In this work a new excitation scheme, Ramsey's method of time-separated oscillatory fields, has been successfully tested. It has been shown to reduce significantly the uncertainty in the determination of the cyclotron frequency and thus of the ion mass of interest. The theoretical description of the ion motion excited with Ramsey's method in a Penning trap and subsequently the calculation of the resonance line shapes for differ…

Preliminary results about the breath of passive smokers and vapers based on the use of portable air monitoring devices

2016

Abstract Preliminary studies were made on the effect of both, classical smoking and electronic cigarettes (ECs) vaping, based on the quality of the indoor air and the breath of passive smokers. Portable air monitoring devices were used to evaluate carbon monoxide (CO), carbon dioxide (CO2), particulate materials (PM), formaldehyde and volatile organic compounds (VOCs) in indoor air and breath of active and passive smokers and vapers. As preliminary results, it can be observed that the major part of PMs liberated in classical smoking and ECs vaping correspond to the lowest size, which is the most dangerous for human health. However, the number of smallest PMs formed during vaping is around 5…

Excitation and detection geometries for Fourier-transform mass spectometry

1994

A short overview of current excitation and detection techniques for Fourier-transform mass spectrometry and related ion cyclotron resonance experiments is given, and some ideas are discussed which may lead to new developments.

First Fourier-transform ion cyclotron resonance signals of very highly charged atomic ions

1994

We report on the first application of Fourier-transform ion cyclotron resonance mass spectrometry to the very highly charged ions produced in the high-energy electron beam ion trap (SuperEBIT) at the Lawrence Livermore National Laboratory. Initial results are described, and spectra are presented from ions as highly charged as Cs53+.

High Resolution Mass Spectrometry of Light Ions in a Penning Trap

1996

Properties and performance of a quadrupole mass filter used for resonance ionization mass spectrometry

1998

Abstract The performance of commercial quadrupole mass spectrometers (QMS) with a number of imperfections, as compared to the ideal hyperbolic geometry, has been characterized using the computer simulation program simion 3d version 6.0. The analysis of simulated QMS geometries focuses primarily on modeling of the internal potential, the study of field deviations, and the influence of finite length on performance of the QMS. The computer simulation of ion trajectories in the QMS field yields predictions for optimum working conditions and provides estimates for the resolving power and the maximum isotopic abundance sensitivity. Experimental measurements that confirm these expectations are pre…

Schools That ‘Open Doors’ to Prevent Child Abuse in Confinement by COVID-19

2020

Background: Due to the expected increase in child abuse during the period of COVID-19 confinement, it is essential that social researchers and other professionals work together very quickly to provide alternatives that protect children. To respond to this extremely urgent demand, evidence-based actions are presented that are being carried out in nine schools in the autonomous communities of Valencia and Murcia, Spain, during the confinement with the goal of “opening doors” to foster supportive relationships and a safe environment to prevent child abuse. Methods: The research was conducted through the inclusion of teachers who are implementing these actions in dialogue with the researchers t…

Scope-Oriented Thermoeconomic analysis of energy systems. Part I: Looking for a non-postulated cost accounting for the dissipative devices of a vapou…

2010

Abstract The authors of the main thermoeconomic methodologies developed in the last two decades have recently focused their efforts on the analysis of dissipative devices, i.e. those components whose productive purpose is neither intuitive nor easy to define. Coherent and unanimously accepted cost structures have been identified for dissipative components, while ambiguities still exist as concerns the cost allocation principles to be adopted. Being this aspect evidently cost-influencing, accurate analyses focused on the subjectivity of results are needed. This paper is structured in two parts. In the Part I an in-depth study of some critical issues arising from the thermoeconomic analysis o…

Characterization of cooling loads in the wine industry and novel seasonal indicator for reliable assessment of energy saving through retrofit of chil…

2020

Abstract The food sector is a major consumer of energy and growing efforts are being made in the search for solutions that will guarantee the efficient and sustainable use of energy resources. Among the different sectors, wineries are attracting particular interest due to the continuous growth of the global market and production. Surveys conducted in the winemaking sector have highlighted the importance of performing accurate energy audits and have identified the installation of efficient refrigeration systems as a promising solution in a variety of cases. Unfortunately, the savings achievable by efficient cooling technologies are often estimated using simplified approaches which do not tak…