52 research outputs found
development of an innovative gas chromatography mass spectrometry method for assessment of formaldehyde in the workplace atmosphere
World consumption of formaldehyde (FA) is forecast to grow at an average annual rate of about 4% from 2015 to 2020 with world production to exceed 52 million tons in 2017. From the first day of January 2016, the Commission Regulation No. 91/2015 established the FA classification through an indication from European Chemical Agency as category 2 mutagenic and category 1B carcinogen. A novel method for the determination of gaseous FA in air is presented herewith. The sampling was carried out using a miniaturized cartridge by means of a medium-flow pumping system (1.0 L min-1, 5–60 min) and absorption of FA vapors on 2,4-dinitrophenylhydrazine. Cartridge desorption removing the excess derivatizing agent based upon solid-phase extraction was performed by an innovative xyz robotic system on-line with fast gas chromatography (GC)—mass spectrometry (MS). Through the generation of standard atmospheres of known concentration of FA, we evaluated the precision (relative standard deviation for n = 10, 8.8%), lower lim..
Assessment of occupational exposure to gaseous peracetic acid
Objectives
In order to assess short-term exposure to peracetic acid (PAA) in disinfection processes, the Authors compared 4 industrial hygiene monitoring methods to evaluate their proficiency in measuring airborne PAA concentrations.
Material and Methods
An active sampling by basic silica gel impregnated with methyl p-tolyl sulfoxide (MTSO), a passive solid phase micro-extraction technique using methyl p-tolyl sulfide (MTS) as on-fiber derivatization reagent, an electrochemical direct-reading PAA monitor, and a novel visual test strip PAA detector doped with 2,2’-azino-bis (3-ethylbenzothiazoline)-6-sulfonate were evaluated and tested over the range of 0.06–16 mg/m3, using dynamically generated PAA air concentrations.
Results
The linear regression analysis of linearity and accuracy showed that the 4 methods were suitable for PAA monitoring. Peracetic acid monitoring in several use applications showed that the PAA concentration (1.8 mg/m3) was immediately dangerous to life or health as proposed by the National Institute of Occupational Safety and Health, and was frequently exceeded in wastewater treatment (up to 7.33 mg/m3), and sometimes during food and beverage processes and hospital high-level disinfection operations (up to 6.8 mg/m3).
Conclusions
The methods were suitable for the quick assessment of acute exposure in PAA environmental monitoring and can assist in improving safety and air quality in the workplace where this disinfectant is used. These monitoring methods allowed the evaluation of changes to work out practices to reduce PAA vapor concentrations during the operations when workers are potentially overexposed to this strong antioxidant agent. Int J Occup Med Environ Health 2018;31(4):527–53
Atributos químicos do solo e estado nutricional de videira Cabernet Sauvignon (Vitis vinifera L.) na Serra Catarinense
The objective of this work was to evaluate the grapevine nutrition and its relation with some soil chemical attributes. The study was carried out in São Joaquim, SC, Southern of Brazil, in a commercial vineyards using Cabernet Sauvignon cv. grafted on Paulsen 1103 rootstock. Soil and plant tissue samples were collected in 21 plots of 240 m2 each, containing four sub plots. The soil chemical attributes evaluated were pH, total acidity (H+Al), organic mater, total N, extractable P and K, and exchangeable Ca, Mg and Al. In tissue were evaluated N, P, K, Ca and Mg. There were differences among blots with regard to soil chemical attributes and the contents of nutrient in both leaves and petioles. The soil presented very high values for organic mater, extractable K and exchangeable Ca and Mg. The contents of N in the petioles and the Ca in both leaves and petioles were below to the intermediate range, according Comissão de Química e Fertilidade do Solo do Rio Grande do Sul e Santa Catarina. The contents of K and the K/Mg ratio in leaves and petioles were above the sufficiency range. There was association between the soil nutrients availability and their contents in the leaves, especially a negatives linear correlation between soil exchangeable K and contents of Mg in the leaves and between soil exchangeable Mg and K in the leaves, confirming the antagonic relationships between these two nutrients in the plant uptake. The soil pH was positively correlated with N contents in petiole. The concentration of K, Ca and Mg in the leaves was better correlated with their saturations in the CEC than with their contents in the soil.O objetivo deste trabalho foi avaliar o estado nutricional de vinhedos cultivados em locais de altitude acima de 1000 m e sua relação com atributos químicos do solo. O estudo foi realizado em São Joaquim, SC, em vinhedos comerciais da cultivar Cabernet Sauvignon, enxertada sobre porta-enxerto Paulsen 1103. As amostras de solo e tecido vegetal foram coletadas em 21 locais, em parcelas de 240 m2, compostas por quatro subparcelas. Os atributos químicos do solo avaliados foram: pH, H+Al, MO e N total, P e K extraíveis, Ca, Mg e Al trocáveis. No tecido foram analisados N, P, K, Ca e Mg. As parcelas apresentaram diferenças significativas entre si nos atributos químicos do solo e teores de nutrientes nas folhas e pecíolos. Os teores de MO, K extraível, Ca e Mg trocáveis do solo se situaram em faixas altas. Observou-se que os teores de N nos pecíolos e de Ca nas folhas e pecíolos se encontraram abaixo da faixa média, conforme a Comissão de Química e Fertilidade do Solo do Rio Grande do Sul e Santa Catarina. Entretanto, os teores de K e a relação K/Mg nas folhas e pecíolos situaram-se acima dessa faixa, enquanto os demais nutrientes estavam dentro da faixa considerada normal. Observou-se associação entre teores dos nutrientes no solo e no tecido foliar, destacando-se a correlação linear negativa entre o teor de K extraível e o teor de Mg no tecido, assim como, entre o teor de Mg trocável do solo e o teor de K no tecido vegetal, evidenciando antagonismo entre estes dois nutrientes na absorção pela planta. O pH do solo se correlacionou positivamente com o teor de N no pecíolo. A concentração de K, Ca e Mg no tecido apresentaram maior correlação com a saturação desses da CTC do que com os teores absolutos desses nutrientes no solo
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Space Objects Behavioral Sciences Telescope
Traditional academic Space Situational Awareness (SSA) research has relied on Consumer Off the Shelf (COTS) systems for collecting metric and lightcurve data. Herein, we present an alternative approach to develop a sensor system for space object characterization. Two 0.6-meter F/4 electro-optical (EO) systems were developed for collecting lightcurve and spectral data. The optomechanical design includes over 200 individual parts and was modeled using SolidWorks. Optical design analysis was performed with raytracing software (ZEMAX). A combinations of test, analysis, inspection, and demonstration procedures verified the components of the design. Methods to complete this project include finite element analysis of mechanical components, optical testing methods (Focault Knife Edge Test and Couder Mask Test), tests to verify the function of the thermometers, and a final pointing model test. The entire cost of the design and fabrication of these two EO systems was significantly lower than a COTS alternative. With careful planning and coordination, the deployment times were also reduced compared to a commercial system. This project shows that development of hardware and software for SSA research could be accomplished in an academic environment
Investigation methods and approaches for alleviating charge trapping phenomena in ohmic RF-MEMS switches submitted to cycling test
We propose and discuss a detailed reliability investigation of ohmic RF-MEMS switches, affected by high
charge trapping phenomena, and we analyse how these test methods affect the study of charge trapping
issues. We investigate the effect of three different parameters that have to be considered when cycling
ohmic RF-MEMS switches. In particular the effect of the shape of the actuation pulse, the cycling frequency
and the RF input power are analysed. Our experimental investigations show interesting trends
and results that might help the analysis of ohmic RF-MEMS switches during cycling tests. These
approaches, in fact, suggest how to better control and to reduce the charge trapping effect maximizing
the lifetime of RF-MEMS switches
An Integrated Air Monitoring Approach for Assessment of Formaldehyde in the Workplace
The aim of this study is to validate an integrated air monitoring approach for assessing airborne formaldehyde (FA) in the workplace. An active sampling by silica gel impregnated with 2,4-dinitrophenylhydrazine, a passive solid phase microextraction technique using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine as on-fiber derivatization reagent, an electrochemical direct-reading monitor, and an enzyme-based badge were evaluated and tested over a range of 0.020–5.12 ppm, using dynamically generated FA air concentrations. Simple linear regression analysis showed the four methods were suitable for evaluating airborne FA. Personal and area samplings in 12 anatomy pathology departments showed that the international occupational exposure limits in the GESTIS database were frequently exceeded. This monitoring approach would allow a fast, easy-to-use, and economical evaluation of both current work practices and eventual changes made to reduce FA vapor concentrations. Keywords: air monitoring, chromatography, electrochemical sensor, enzyme-based badge, formaldehyd
Association between smartphone-based activity monitoring and traditional clinical assessment tools in community-dwelling older people
none6noSmartphones are used in the framework of the FARSEEING-InChianti study to gain information on activities of daily living and define objective physical activity profiles. In this study we aimed to investigate the association between mean and extreme values of physical activity and gait characteristics derived from daily living activities and well-established clinical tools. 171 older adults from the InChianti cohort study were recruited. Factor analysis was performed to extract the underlying structure of physical activity and gait features for both mean and extreme values. Outcomes of the smartphone-based home monitoring are associated with clinical assessments. Extreme values seem to be more informative than the mean values and are more closely related with clinical assessments.mixedConi, Alice; Mellone, Sabato; Leach, Julia M.; Colpo, Marco; Bandinelli, Stefania; Chiari, LorenzoConi, Alice; Mellone, Sabato; Leach, Julia M.; Colpo, Marco; Bandinelli, Stefania; Chiari, Lorenz
Adherence to a Mediterranean Diet Protects from Cognitive Decline in the Invecchiare in Chianti Study of Aging
Following a Mediterranean diet high in plant-based foods and fish, low in meat and dairy foods, and with moderate alcohol intake has been shown to promote healthy aging. Therefore, we examined the association between a Mediterranean diet and trajectories of cognitive performance in the InCHIANTI study. Subjects (N = 832) were examined every 2⁻3 years up to 18 years with an average follow-up period of 10.1 years. Cognitive performance was assessed using the Mini Mental State Examination (MMSE) at every visit. Dietary habits were assessed using a validated food frequency questionnaire and adherence to Mediterranean diet was computed on a scale of 0-9 and categorized into three groups of low (≤3), medium (4⁻5), and high (≥6). Those in the highest adherence group (OR = 0.48, 95% CI: 0.29⁻0.79) and medium adherence group (OR = 0.64, 95% CI: 0.41⁻0.99) were less likely to experience cognitive decline. The annual average decline in MMSE scores was 0.4 units, for those in the high and medium adherence group this decline was attenuated by 0.34 units (p < 0.001) and 0.16 units (p = 0.03), respectively. Our findings suggest that adherence to a Mediterranean diet can have long-lasting protective effects on cognitive decline and may be an effective strategy for the prevent or delay dementia
Reliability of RF-MEMS switches for efficient Satellite telecommunications
We subjected Organic Thin-Film-Transistors with different gate dielectrics interface treatment to visible light and low energy UV irradiation. Devices with silicon nanoparticles only feature a remarkable temporary charge trapping, regardless the irradiation wavelength. On the contrary, devices without silicon nanoparticles feature temporary trapped charge under visible light, and permanent mobility degradation if they are irradiated with a wavelength shorter than 420 nm
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