scholarly journals Formaldehyde Emissions from Wooden Toys: Comparison of Different Measurement Methods and Assessment of Exposure

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 262
Author(s):  
Morgane Even ◽  
Olaf Wilke ◽  
Sabine Kalus ◽  
Petra Schultes ◽  
Christoph Hutzler ◽  
...  
Keyword(s):  
Steady State ◽  
Exposure Assessment ◽  
Correlation Coefficient ◽  
Test Chamber ◽  
Measurement Methods ◽  
High Variability ◽  
Market Surveillance ◽  
Formaldehyde Release ◽  
Alternative Method

Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 µg/m3), especially when more conservative exposure scenarios were considered.

scholarly journals Thermal conductivity of insulating refractory materials: comparison of steady-state and transient measurement methods

Open Ceramics ◽  
2021 ◽  
pp. 100118
Author(s):  
Diana Vitiello ◽  
Benoit Nait-Ali ◽  
Nicolas Tessier-Doyen ◽  
Thorsten Tonnesen ◽  
Luís Laím ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Measurement Methods ◽  
Refractory Materials ◽  
Transient Measurement

Experimental amplitude and frequency control of a self-excited microcantilever by linear and nonlinear feedback

2021 ◽  
Author(s):  
Eisuke Higuchi ◽  
Hiroshi Yabuno ◽  
Yasuyuki Yamamoto ◽  
Sohei Matsumoto
Keyword(s):  
Steady State ◽  
Frequency Control ◽  
High Sensitivity ◽  
High Viscosity ◽  
Measurement Methods ◽  
Nonlinear Feedback ◽  
Force Microscopy ◽  
Atomic Force ◽  
Excited Oscillation ◽  
Experimental Approaches

Abstract In recent years, measurement methods that use resonators as microcantilevers have attracted attention because of their high sensitivity, high accuracy, and rapid response time. They have been widely utilized in mass sensing, stiffness sensing, and atomic force microscopy (AFM), among other applications. In all these methods, it is essential to accurately detect shifts in the natural frequency of the resonator caused by an external force from a measured object or sample. Experimental approaches based on self-excited oscillation enable the detection of these shifts even when the resonator is immersed in a high-viscosity environment. In the present study, we experimentally and theoretically investigate the nonlinear characteristics of a microcantilever resonator and their control by nonlinear feedback. We show that the steady-state response amplitude and the corresponding response frequency can be controlled by cubic nonlinear velocity feedback and cubic nonlinear displacement feedback, respectively. Furthermore, the amplitude and frequency of the steady-state self-excited oscillation can be controlled separately. These results will expand application of measurement methods that use self-excited resonators.

ASSESSMENT OF MULTIPLE MARKERS OF ENVIRONMENTAL TOBACCO SMOKE (ETS) IN CONTROLLED, STEADY-STATE ATMOSPHERES IN A DYNAMIC TEST CHAMBER

AIHAJ ◽  
1992 ◽  
Vol 53 (11) ◽  
pp. 699-704 ◽  
Author(s):  
Roy J. Rando ◽  
Prem K. Menon ◽  
Halet G. Poovey ◽  
Samuel B. Lehrer
Keyword(s):  
Steady State ◽  
Environmental Tobacco Smoke ◽  
Tobacco Smoke ◽  
Test Chamber ◽  
Dynamic Test ◽  
Multiple Markers

scholarly journals Exposure assessment method for products containing carbon nanotubes inside a test chamber with a Taber abrasion machine

2017 ◽  
Vol 838 ◽  
pp. 012011
Author(s):  
Yasuto Matsui ◽  
Taiki Nagaya ◽  
Kato Nobuyuki ◽  
Tomonori Ishibashi ◽  
Minoru Yoneda
Keyword(s):  
Carbon Nanotubes ◽  
Exposure Assessment ◽  
Test Chamber ◽  
Assessment Method

scholarly journals Comparison of Emission Measurement Methods for Electromagnetic Disturbances in the Frequency Range from 30 MHz to 300 MHz for LED Lamps According to EN 55015

2019 ◽  
Vol 63 (2) ◽  
pp. 106-111
Author(s):  
Kazimierz Kamuda ◽  
Dariusz Klepacki ◽  
Kazimierz Kuryło ◽  
Wiesław Sabat
Keyword(s):  
Correlation Coefficient ◽  
Linear Correlation ◽  
Traditional Method ◽  
Measurement Methods ◽  
The Other ◽  
Emission Measurement ◽  
Frequency Range ◽  
Statistical Tools ◽  
Equivalent Method ◽  
Electromagnetic Disturbances

The results of measurements of electromagnetic disturbances emitted by LED lamps, in the frequency range from 30 MHz to 300 MHz, which were made using two methods described in the EN 55015/2013 standard have been presented in the paper. In order to compare both methods, each tested lamp was first measured using the traditional method described in Section4.4.2 and then tested by an alternative, equivalent method described in Annex B of the above-mentioned standard. The comparison of results for both methods indicates that using first method, a given LED lamp emits disturbances below the acceptable limits, while the same LED lamp tested with the second method emits disturbances that are at the limit of admissible values. Additionally, used statistical tools in the form of calculated linear correlation coefficient show that the nature of the emission of disturbances measured for the same lamp is very comparable in both methods. The reference of these quasi-peak values to the permissible limits applicable in one or the other method may lead to different decisions.

Prediction of collective opinion in consensus formation

2014 ◽  
Vol 25 (04) ◽  
pp. 1450002 ◽  
Author(s):  
Lei Hou ◽  
Jianguo Liu ◽  
Xue Pan ◽  
Wen-Jun Song ◽  
Xu-Dong Li
Keyword(s):  
Steady State ◽  
Theoretical Analysis ◽  
Linear Relationship ◽  
Correlation Coefficient ◽  
Opinion Leaders ◽  
Formation Model ◽  
Opinion Formation ◽  
Consensus Formation ◽  
Final State ◽  
Formation Dynamics

In the consensus formation dynamics, the effect of leaders and interventions have been widely studied for it has many applications such as in politics and commerce. However, the problem is how to know if it is necessary for one to make an intervention. In this paper, we theoretically propose a method for predicting the tendency and final state of collective opinion. By giving each agent a conviction ci which measures the ability to insist on his opinion, we present an opinion formation model in which agents with high convictions naturally show up properties of the opinion leaders. Results reveal that, although each agent initially gets an opinion evenly distributed in the range [-1, 1], the collective opinion of the steady-state may deviate to the positive or negative direction because of the initial bias of the leaders' opinions. We further get the correlation coefficient of the linear relationship between the collective opinion and the initial bias according to both the experimental and theoretical analysis. Thus, we could predict the final state at the very beginning of the dynamic only if we get the opinions of a small portion of the population. The prediction would afford us more time and opportunities to make reactions and interventions.

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