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[en] Electrostatic collection technique is widely used in various radon monitors. The mechanism of this kind of radon monitor is that the positive Po particles, produced by decay of radon, can be collected on the surface of detector in electric field. Collection efficiency, therefore, could be affected by air humidity. Calibration under different humidity conditions or test of humidity response is necessary consequently. In this study, a humidity control technique based on Nafion membrane tube (NMT) is developed. Under a consistent flowrate with a certain stable level of radon concentration and humidity of main-path inlet, the humidity of outlet sample gas from the main-path can be adjusted and stably controlled at a certain level by changing side-path's flowrates of NMT. By adjusting main and side-path flowrate, RH of outlet gas of the main-path can be controlled from 5.3 to 80.0%. Theoretical study were also performed. Based on this, humidity influence calibration of an electrostatic radon monitor was performed, and a relationship between the sensitivity of the radon monitor and relative humidity was obtained. (authors)
[en] A common coldrex, paracetamol, was used as humidity sensing material. The capacitance-type humidity sensor was fabricated by aerosol deposition method. The humidity sensitive properties were investigated through dielectric measurements. Our results reveal that the sensor has exciting performances in high relative humidity. Both −OH and −NH groups have contributions to water absorption. The −OH groups lead to a water-containing surface layer giving rise to pronounced Maxwell-Wagner response, which in turn, yields the humidity response that can be easily adjusted by an external electric field. This work indicates that the paracetamol is a promising humidity sensing material. (paper)
[en] Highlights: • Shrinkage of concrete is measured with various temperature and humidity conditions. • The fib MC2010 shrinkage model is accurate for low RH and high T conditions. • The fib MC2010 shrinkage model slightly underestimate for other conditions. • The fib MC2010 creep model conservatively predicts creep strains. - Abstract: Creep and shrinkage of concrete is influenced by many factors including relative humidity and temperature. The combined effect of low relative humidity (<20%) and high temperature (38 °C) on creep and shrinkage of concrete is uncertain as limited tests have been conducted in this domain. Also unknown is the ability of the fib MC2010 model code in predicting the shrinkage and creep at the environment. This paper presents the results of experiments conducted in which concrete was cast and exposed to the aforementioned environmental conditions. The shrinkage and creep behaviour of the concrete was observed for 110 days, and experimental results were compared with predicted values using fib MC2010 model code.
[en] Recording high quality biosignals by dry textile electrodes is a common challenge in medical health monitoring garments. The aim of this study was to improve skin–electrode interface and enhance the quality of recorded electrocardiography (ECG) signals by modification of textile electrodes embedded in WearItMed smart garment. The garment has been developed for long-term health monitoring in patients suffering from epilepsy and Parkinson’s disease. A skin-friendly electro-conductive elastic paste was formulated to coat and modify the surface of the knitted textile electrodes. The modifications improved the surface characteristics of the electrodes by promoting a more effective contact area between skin and electrode owing to a more even surface, fewer pores, greater surface stability against touch, and introduction of humidity barrier properties. The modifications decreased the skin–electrode contact impedance, and consequently improved the recorded ECG signals obviously when low pressure was applied to the electrodes, therefore contributed to greater patient comfort. The created contact surface allowed the natural humidity of the skin/sweat to ease the signal transfer between the electrode and the body, while introducing a shorter settling time and retaining moisture over a longer time. Microscopic images, ECG signal measurements, electrode–skin contact impedance at different pressures and times, and water absorbency were measured and reported.
[en] In spite of extensive investigation and applications, influence of oxygen (O), and humidity on polyaniline (PANI) behaviour is not well understood. For this reason we have performed semi-empirical quantum mechanics, and ab-initio calculations of the pernigraniline base (PNB) PANI oligomers, of various lengths, before and after approach of H2O, O2 , and hydroxyl (OH −) group, and attachment of OH − and O to various molecular positions. Structure, charge and electrostatic potential distribution, relevant energies and enthalpies, infrared and electronic spectra of the PNB tetramer equilibrium conformation, and their changes induced by specific OH − , and O attachments are determined. These results provide identification of the most probable positions for O2 and H2O approach to PNB_PANI, enthalpies of OH − and O attachments to them, changes of molecular properties induced by the attachments, and infrared and electronic modes that are most suitable for the attachments detection. The results are compared to the existing experimental data, and the results of similar calculations, and implications for the PNB_PANI applications are notified. © 2019 Elsevier B.V.
[en] Recently, the humidity sensors have captivated huge attention for making human life more comfortable and to diagnose several diseases. Here, we reported the excellent humidity responsiveness of V0.5Sn0.5Se2 ternary alloy for human breath monitoring and touchless positioning interface. The resistive sensor based on direct vapour transport grown bulk crystal of V0.5Sn0.5Se2 ternary alloy is fabricated and explored for its static response in different humidity levels ranging from 20 to 90%. The sensor showed excellent dynamic switching characteristics between relative humidity of 20% and 90% with responsivity of 6.78%, response time of 3.2 s and recovery time of 2.3 s. Subsequently, the sensor is exploited for giant responsiveness for human breath monitoring and words recognitions. The sensor exhibited quite distinct response towards different words namely, “Pratik”, “Chetan” and “Mohit”. Besides, novel touch-less positioning interface is explained with respect to humidity variation. Overall, the results advocate development of resistive sensors for intended humidity, biomedical as well as for intelligent touch-less sensing applications.
[en] Steel is a very versatile metallic material and widely used in modern life. Unfortunately, this material is prone to the phenomenon of corrosion and over time, can contribute to the failure of the product. In order to minimize this process, different types of coatings are used, due to their efficiency, economy and ease of application. The degradation of the film applied to steel by atmospheric agents is the result of the combination of various environmental factors, due to the highly destructive cyclic variations. The present work intends to determine the existence of significant statistical differences in the thickness distribution of coating in duplex systems (Fe/Zn/Paint), before and after conducting the humidity and temperature test with condensation in a constant atmosphere, from different tests carried out in the Stat graphics Centurion software. The influence of the preset conditions on the coating thickness before and after the test was demonstrated was demonstrated. These values were found in a suitable interval to guarantee the resistance to corrosion, not showing visible deterioration in the surface of the analyzed specimens.
[es]El acero es un material metálico muy versátil y ampliamente utilizado en la vida moderna. Desafortunadamente, este material está propenso al fenómeno de la corrosión y el pasar del tiempo, puede contribuir a la falla del producto. Para lograr minimizar este proceso se utilizan diferentes tipos de recubrimientos, debido a su eficacia, economía y facilidad de aplicación. La degradación de la película aplicada sobre el acero por los agentes atmosféricos es resultado de la combinación de diversos factores ambientales, debido a las variaciones cíclicas altamente destructivas. El presente trabajo pretende determinar la existencia de diferencias estadísticas significativas en las distribuciones del espesor de recubrimiento en sistemas dúplex (Fe/Zn/Pintura), antes y después de realizado el ensayo de humedad y temperatura con condensación en atmósfera constante, a partir de diferentes pruebas realizadas en el software Statgraphics Centurion. Se demostró la influencia de las condiciones prefijadas sobre el espesor de recubrimiento antes y después de realizado el ensayo. Dichos valores se encontraron en un intervalo adecuado para garantizar la resistencia a la corrosión, no evidenciándose deterioro visible en la superficie de las probetas analizadas.
[en] To further improve the application of cosmic-ray neutron sensor technology, the SWMCN Laboratory during the summer validated the footprint, effective depth and accuracy of the mobile or “backpack” version of the sensor. Through sixteen different calibrations for five research sites in Austria, located between 300 and 1700 m a.s.l., a comparison was made between the volumetric water content measured by the backpack and gravimetric measurements for different radii of influence. Results indicated similar outcomes based on a 0-75-meter footprint as compared to a 0-200 meter study suggesting that measurements by the mobile cosmic-ray neutron sensor have a footprint with a 200-meter radius (i.e. 20 hectares). The same data were also used to determine the effective depth, results showed that the effective depth is about 10 cm for volumetric water contents ranging between 30 and 60%.
[en] Focusing on the scalability of Two-Filter Method, we started to develop a monitor for the concentration of radon and its progeny. In this study, we investigated the influence of a high-humidity environment on measuring radon concentration, and the influence of the decay chamber of the monitor on the measurement. In the high-humidity test, the conversion factor of (Bqm-3)/(cpm) tends to raise with increasing humidity. On the measurement of radon progeny, existence of the decay chamber of the monitor makes measurement sensitivity lower under environments of little aerosols. Radon concentration measurement by the developed monitor could be influenced by environmental humidity, and that counting loss could occur due to deposition of radon progeny inside of the decay chamber. Correction relating these would be needed based on the data of calibration tests. (authors)
[en] Here, we report the preparation of PEDOT:PSS-MoS2 nanocomposite thin films and their electrical resistance response under humidity conditions revealing their promising properties as humidity sensor materials. One of the most interesting features of our samples is the transition from positive to a negative electrical resistance response to humidity conditions with increasing MoS2 additions. Our confocal Raman imaging studies revealed that the presence of MoS2 yields a local charge rearrangement in the thiophenyl rings of PEDOT:PSS, in relation to the enhancement of the electrical resistance negative response as observed by impedance spectroscopy analysis. The enhancement on the negative response with increasing MoS2 additions could be explained through the increment of hole carriers in MoS2 nanosheets under humidity conditions, thus leading to an enhancement in the electrical transport along the PEDOT:PSS chains.