WorldWideScience

Sample records for environment relative humidity

  1. An Inexpensive, Stable, and Accurate Relative Humidity Measurement Method for Challenging Environments.

    Science.gov (United States)

    Zhang, Wei; Ma, Hong; Yang, Simon X

    2016-03-18

    In this research, an improved psychrometer is developed to solve practical issues arising in the relative humidity measurement of challenging drying environments for meat manufacturing in agricultural and agri-food industries. The design in this research focused on the structure of the improved psychrometer, signal conversion, and calculation methods. The experimental results showed the effect of varying psychrometer structure on relative humidity measurement accuracy. An industrial application to dry-cured meat products demonstrated the effective performance of the improved psychrometer being used as a relative humidity measurement sensor in meat-drying rooms. In a drying environment for meat manufacturing, the achieved measurement accuracy for relative humidity using the improved psychrometer was ±0.6%. The system test results showed that the improved psychrometer can provide reliable and long-term stable relative humidity measurements with high accuracy in the drying system of meat products.

  2. Calibration of Relative Humidity Devices in Low-pressure, Low-temperature CO2 Environment

    Science.gov (United States)

    Genzer, Maria; Polkko, Jouni; Nikkanen, Timo; Hieta, Maria; Harri, Ari-Matti

    2017-04-01

    Calibration of relative humidity devices requires in minimum two humidity points - dry (0%RH) and (near)saturation (95-100%RH) - over the expected operational temperature and pressure range of the device. In terrestrial applications these are relatively easy to achieve using for example N2 gas as dry medium, and water vapor saturation chambers for producing saturation and intermediate humidity points. But for example in applications intended for meteorological measurements on Mars there is a need to achieve at least dry and saturation points in low-temperature, low-pressure CO2 environment. We have developed a custom-made, small, relatively low-cost calibration chamber able to produce both dry points and saturation points in Martian range pressure CO2, in temperatures down to -70°C. The system utilizes a commercially available temperature chamber for temperature control, vacuum vessels and pumps. The main pressure vessel with the devices under test inside is placed inside the temperature chamber, and the pressure inside is controlled by pumps and manual valves and monitored with a commercial pressure reference with calibration traceable to national standards. Air, CO2, or if needed another gas like N2, is used for filling the vessel until the desired pressure is achieved. Another pressure vessel with a dedicated pressure pump is used as the saturation chamber. This vessel is placed in the room outside the temperature chamber, partly filled with water and used for achieving saturated water vapor in room-temperature low-pressure environment. The saturation chamber is connected to the main pressure vessel via valves. In this system dry point, low-pressure CO2 environment is achieved by filling the main pressure vessel with dry CO2 gas until the desired pressure is achieved. A constant flow of gas is maintained with the pump and valves and monitored with the pressure reference. The saturation point is then achieved by adding some water vapor from the saturation

  3. Effect of relative humidity on the tribological properties of hydrogenated diamond-like carbon films in a nitrogen environment

    International Nuclear Information System (INIS)

    Li Hongxuan; Xu Tao; Wang Chengbing; Chen Jianmin; Zhou Huidi; Liu Huiwen

    2005-01-01

    Hydrogenated diamond-like carbon (DLC) films were deposited on Si (100) wafers by a plasma enhanced chemical vapour deposition technique using CH 4 plus Ar as the feedstock. The friction and wear properties of the resulting films under different relative humidities, ranging from 5% to 100%, in a nitrogen environment, were measured using a ball-on-disc tribometer, with Si 3 N 4 balls as the counterparts. The friction surfaces of the films and Si 3 N 4 balls were observed on a scanning electron microscope, and investigated by x-ray photoelectron spectroscopy. The results showed that the friction coefficient increased continuously from 0.025 to 0.09 with increase in relative humidity from 5% to 100%, while the wear rate of the films sharply decreased and reached a minimum at a relative humidity of 40%, then it increased with further increase of the relative humidity. The interruption of the transferred carbon-rich layer on the Si 3 N 4 ball, and the friction-induced oxidation of the films at higher relative humidity were proposed as the main reasons for the increase in the friction coefficient. Moreover, the oxidation and hydrolysis of the Si 3 N 4 ball at higher relative humidity, leading to the formation of a tribochemical film, which mainly consists of silica gel, on the friction surface, are also thought to influence the friction and wear behaviour of the hydrogenated DLC films

  4. Measuring relative humidity in the radioactive environment of the IRRAD proton facility

    CERN Document Server

    Paerg, Marten

    2017-01-01

    The aim of the project was to obtain information on relative humidity conditions at different locations in the IRRAD proton facility. Due to high radiation levels inside the facility, different sensors had to be qualified and dedicated electronics had to be built to transfer the data of the sensors over long wires to a less radioactive area, where it could be collected.

  5. Odors and sensations of humidity and dryness in relation to sick building syndrome and home environment in Chongqing, China.

    Directory of Open Access Journals (Sweden)

    Juan Wang

    Full Text Available The prevalence of perceptions of odors and sensations of air humidity and sick building syndrome symptoms in domestic environments were studied using responses to a questionnaire on the home environment. Parents of 4530 1-8 year old children from randomly selected kindergartens in Chongqing, China participated. Stuffy odor, unpleasant odor, pungent odor, mold odor, tobacco smoke odor, humid air and dry air in the last three month (weekly or sometimes was reported by 31.4%, 26.5%, 16.1%, 10.6%, 33.0%, 32.1% and 37.2% of the parents, respectively. The prevalence of parents' SBS symptoms (weekly or sometimes were: 78.7% for general symptoms, 74.3% for mucosal symptoms and 47.5% for skin symptoms. Multi-nominal regression analyses for associations between odors/sensations of air humidity and SBS symptoms showed that the odds ratio for "weekly" SBS symptoms were consistently higher than for "sometimes" SBS symptoms. Living near a main road or highway, redecoration, and new furniture were risk factors for perceptions of odors and sensations of humid air and dry air. Dampness related problems (mold spots, damp stains, water damage and condensation were all risk factors for perceptions of odors and sensations of humid air and dry air, as was the presence of cockroaches, rats, and mosquitoes/flies, use of mosquito-repellent incense and incense. Protective factors included cleaning the child's bedroom every day and frequently exposing bedding to sunshine. In conclusion, adults' perceptions of odors and sensations of humid air and dry air are related to factors of the home environment and SBS symptoms are related to odor perceptions.

  6. Static flexural properties of hedgehog spines conditioned in coupled temperature and relative humidity environments.

    Science.gov (United States)

    Kennedy, Emily B; Hsiung, Bor-Kai; Swift, Nathan B; Tan, Kwek-Tze

    2017-11-01

    Hedgehogs are agile climbers, scaling trees and plants to heights exceeding 10m while foraging insects. Hedgehog spines (a.k.a. quills) provide fall protection by absorbing shock and could offer insights for the design of lightweight, material-efficient, impact-resistant structures. There has been some study of flexural properties of hedgehog spines, but an understanding of how this keratinous biological material is affected by various temperature and relative humidity treatments, or how spine color (multicolored vs. white) affects mechanics, is lacking. To bridge this gap in the literature, we use three-point bending to analyze the effect of temperature, humidity, spine color, and their interactions on flexural strength and modulus of hedgehog spines. We also compare specific strength and stiffness of hedgehog spines to conventional engineered materials. We find hedgehog spine flexural properties can be finely tuned by modifying environmental conditioning parameters. White spines tend to be stronger and stiffer than multicolored spines. Finally, for most temperature and humidity conditioning parameters, hedgehog spines are ounce for ounce stronger than 201 stainless steel rods of the same diameter but as pliable as styrene rods with a slightly larger diameter. This unique combination of strength and elasticity makes hedgehog spines exemplary shock absorbers, and a suitable reference model for biomimicry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Health symptoms in relation to temperature, humidity, and self-reported perceptions of climate in New York City residential environments

    Science.gov (United States)

    Quinn, Ashlinn; Shaman, Jeffrey

    2017-07-01

    Little monitoring has been conducted of temperature and humidity inside homes despite the fact that these conditions may be relevant to health outcomes. Previous studies have observed associations between self-reported perceptions of the indoor environment and health. Here, we investigate associations between measured temperature and humidity, perceptions of indoor environmental conditions, and health symptoms in a sample of New York City apartments. We measured temperature and humidity in 40 New York City apartments during summer and winter seasons and collected survey data from the households' residents. Health outcomes of interest were (1) sleep quality, (2) symptoms of heat illness (summer season), and (3) symptoms of respiratory viral infection (winter season). Using mixed-effects logistic regression models, we investigated associations between the perceptions, symptoms, and measured conditions in each season. Perceptions of indoor temperature were significantly associated with measured temperature in both the summer and the winter, with a stronger association in the summer season. Sleep quality was inversely related to measured and perceived indoor temperature in the summer season only. Heat illness symptoms were associated with perceived, but not measured, temperature in the summer season. We did not find an association between any measured or perceived condition and cases of respiratory infection in the winter season. Although limited in size, the results of this study reveal that indoor temperature may impact sleep quality, and that thermal perceptions of the indoor environment may indicate vulnerability to heat illness. These are both important avenues for further investigation.

  8. Relative Humidity and the Susceptibility of Austenitic Stainless Steel to Stress Corrosion Cracking in an impure Plutonium Oxide Environment

    Energy Technology Data Exchange (ETDEWEB)

    Zapp, P.; Duffey, J.; Lam, P.; Dunn, K.

    2010-05-05

    Laboratory tests to investigate the corrosivity of moist plutonium oxide/chloride salt mixtures on 304L and 316L stainless steel coupons showed that corrosion occurred in selected samples. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The exposures were conducted in sealed containers in which the oxide-salt mixtures were loaded with about 0.6 wt % water from a humidified helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration, the composition of the salt and the moisture present in the test environment. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride and 0.6 wt% water. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas above the solid mixture, or in coupons exposed to other mixtures with either no CaCl{sub 2} or 0.92 wt% CaCl{sub 2}. SCC was present where the 0.6 wt % water content exceeded the value needed to fully hydrate the available CaCl{sub 2}, but was absent where the water content was insufficient. These results reveal the significance of the relative humidity in the austenitic stainless steels environment to their susceptibility to corrosion. The relative humidity in the test environment was controlled by the water loading and the concentration of the hydrating salts such as CaCl{sub 2}. For each salt or salt mixture there is a threshold

  9. Variations of relative humidity in relation to meningitis in Africa

    Science.gov (United States)

    Seefeldt, M. W.; Hopson, T. M.

    2011-12-01

    The meningitis belt is a region covering Sub-Saharan Africa from the Sahel of West Africa eastward to western Ethiopia. The region is prone to meningitis epidemics during the dry season extending from approximately January to May, depending on the region. Relative humidity has been found to be a critical environmental factor indicating the susceptibility of a region to meningitis epidemics. This study evaluates the variation of relative humidity across West Africa over 30 dry-seasons (1979 - 2009) using the NASA-MERRA dataset. The method of self-organizing maps is employed to characterize the changes in relative humidity patterns across the region within a given dry season as well as changes over the 30 years. A general pattern of changes in relative humidity is indicated as the rainbelt retreats to the south at the onset of the dry season and then returns to the region at the end of the dry season. Within each dry season there is a unique pattern. The climatological conditions of relative humidity at the onset of the dry season provide an indication of the moisture environment for the entire dry season. Year to year variation in the relative humidity patterns are found to be gradual. Future applications involve using the results from the SOM evaluation to be used for future decisions involving prevention of meningitis epidemics.

  10. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Lachowski, Eric E.

    1999-01-01

    and experimental data are presented showing that C(3)A can hydrate at lower humidities than either C3S or C2S. It is suggested that the initiation of hydration during exposure to water vapour is nucleation controlled. When C(3)A hydrates at low humidity, the characteristic hydration product is C(3)AH(6......Vapour phase hydration of purl cement clinker minerals at reduced relative humidities is described. This is relevant to modern high performance concrete that may self-desiccate during hydration and is also relevant to the quality of the cement during storage. Both the oretical considerations...

  11. Is Obsidian Hydration Dating Affected by Relative Humidity?

    Science.gov (United States)

    Friedman, I.; Trembour, F.W.; Smith, G.I.; Smith, F.L.

    1994-01-01

    Experiments carried out under temperatures and relative humidities that approximate ambient conditions show that the rate of hydration of obsidian is a function of the relative humidity, as well as of previously established variables of temperature and obsidian chemical composition. Measurements of the relative humidity of soil at 25 sites and at depths of between 0.01 and 2 m below ground show that in most soil environments, at depths below about 0.25 m, the relative humidity is constant at 100%. We have found that the thickness of the hydrated layer developed on obsidian outcrops exposed to the sun and to relative humidities of 30-90% is similar to that formed on other portions of the outcrop that were shielded from the sun and exposed to a relative humidity of approximately 100%. Surface samples of obsidian exposed to solar heating should hydrate more rapidly than samples buried in the ground. However, the effect of the lower mean relative humidity experiences by surface samples tends to compensate for the elevated temperature, which may explain why obsidian hydration ages of surface samples usually approximate those derived from buried samples.

  12. Study on radon concentration monitoring using activated charcoal canisters in high humidity environments

    International Nuclear Information System (INIS)

    Wang Yuexing; Wang Haijun; Yang Yifang; Qin Sichang; Wang Zhentao; Zhang Zhenjiang

    2009-01-01

    The effects of humidity on the sensitivity using activated charcoal canisters for measuring radon concentrations in high humidity environments were studied. Every canister filled with 80 g of activated charcoal, and they were exposed to 48 h or 72 h in the relative humidity of 68%, 80%, 88% and 96% (28 degree C), respectively. The amount of radon absorbed in the canisters was determined by counting the gamma rays from 214 Pb and 214 Bi (radon progeny). The results showed that counts decreased with the increase of relative humidity. There was a negative linear relationship between count and humidity. In the relative humidity range of 68%-96%, the sensitivity of radon absorption decreased about 2.4% for every 1% (degree)rise in humidity. The results also showed that the exposure time of the activated charcoal canisters should be less than 3 days. (authors)

  13. Clinker mineral hydration at reduced relative humidities

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede

    1998-01-01

    This report deals with gas phase hydration of pure cement clinker minerals at reduced relative humidities. This is an important subject in relation to modern high performance concrete which may self-desiccate during hydration. In addition the subject has relevance to storage stability where...... prehydration may occur. In the report both theoretical considerations and experimental data are presented. It is suggested that the initiation of hydration during water vapour exposure is nucleation controlled....

  14. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold. Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  15. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold.

    Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  16. Effect of relative humidity on solar potential

    International Nuclear Information System (INIS)

    Soezen, Adnan; Arcaklioglu, Erol

    2005-01-01

    In this study, the effect of relative humidity on solar potential is investigated using artificial neural-networks. Two different models are used to train the neural networks. Meteorological and geographical data (latitude, longitude, altitude, month, mean sunshine-duration, and mean temperature) are used in the input layer of the network (Model 1). But, relative humidity values are added to one network in model (Model 2). In other words, the only difference between the models is relative humidity. New formulae based on meteorological and geographical data, have been developed to determine the solar energy potential in Turkey using the networks' weights for both models. Scaled conjugate gradient (SCG) and Levenberg-Marquardt (LM) learning algorithms and a logistic sigmoid transfer-function were used in the network. The best approach was obtained by the SCG algorithm with nine neurons for both models. Meteorological data for the four years, 2000-2003, for 18 cities (Artvin, Cesme, Bozkurt, Malkara, Florya, Tosya, Kizilcahamam, Yenisehir, Edremit, Gediz, Kangal, Solhan, Ergani, Selcuk, Milas, Seydisehir, Siverek and Kilis) spread over Turkey have been used as data in order to train the neural network. Solar radiation is in output layer. One month for each city was used as test data, and these months have not been used for training. The maximum mean absolute percentage errors (MAPEs) for Tosya are 2.770394% and 2.8597% for Models 1 and 2, respectively. The minimum MAPEs for Seydisehir are 1.055205% and 1.041% with R 2 (99.9862%, 99.9842%) for Models 1 and 2, respectively, in the SCG algorithm with nine neurons. The best value of R 2 for Models 1 and 2 are for Seydisehir. The minimum value of R 2 for Model 1 is 99.8855% for Tosya, and the value for Model 2 is 99.9001% for Yenisehir. Results show that the humidity has only a negligible effect upon the prediction of solar potential using artificial neural-networks

  17. Relative Humidity in the Tropopause Saturation Layer

    Science.gov (United States)

    Selkirk, H. B.; Schoeberl, M. R.; Pfister, L.; Thornberry, T. D.; Bui, T. V.

    2017-12-01

    The tropical tropopause separates two very different atmospheric regimes: the stable lower stratosphere where the air is both extremely dry and nearly always so, and a transition layer in the uppermost tropical troposphere, where humidity on average increases rapidly downward but can undergo substantial temporal fluctuations. The processes that control the humidity in this layer below the tropopause include convective detrainment (which can result in either a net hydration or dehydration), slow ascent, wave motions and advection. Together these determine the humidity of the air that eventually passes through the tropopause and into the stratosphere, and we refer to this layer as the tropopause saturation layer or TSL. We know from in situ water vapor observations such as Ticosonde's 12-year balloonsonde record at Costa Rica that layers of supersaturation are frequently observed in the TSL. While their frequency is greatest during the local rainy season from June through October, supersaturation is also observed in the boreal winter dry season when deep convection is well south of Costa Rica. In other words, local convection is not a necessary condition for the presence of supersaturation. Furthermore, there are indications from airborne measurements during the recent POSIDON campaign at Guam that if anything deep convection tends to `reset' the TSL locally to a state of just-saturation. Conversely, it may be that layers of supersaturation are the result of slow ascent. To explore these ideas we take Ticosonde water vapor observations from the TSL, stratify them on the basis of relative humidity and report on the differences in the the history of upstream convective influence between supersaturated parcels and those that are not.

  18. Calibration of Relative Humidity Sensors using a Dew Point Generator

    OpenAIRE

    Brooks, Milo

    2010-01-01

    A relative humidity sensor can be calibrated using a dew point generator to continuously supply an air stream of known constant humidity and a temperature chamber to control the dew point and ambient temperature.

  19. Performance limit of daytime radiative cooling in warm humid environment

    Directory of Open Access Journals (Sweden)

    Takahiro Suichi

    2018-05-01

    Full Text Available Daytime radiative cooling potentially offers efficient passive cooling, but the performance is naturally limited by the environment, such as the ambient temperature and humidity. Here, we investigate the performance limit of daytime radiative cooling under warm and humid conditions in Okayama, Japan. A cooling device, consisting of alternating layers of SiO2 and poly(methyl methacrylate on an Al mirror, is fabricated and characterized to demonstrate a high reflectance for sunlight and a selective thermal radiation in the mid-infrared region. In the temperature measurement under the sunlight irradiation, the device shows 3.4 °C cooler than a bare Al mirror, but 2.8 °C warmer than the ambient of 35 °C. The corresponding numerical analyses reveal that the atmospheric window in λ = 16 ∼ 25 μm is closed due to a high humidity, thereby limiting the net emission power of the device. Our study on the humidity influence on the cooling performance provides a general guide line of how one can achieve practical passive cooling in a warm humid environment.

  20. Effect of relative humidity on growth of sodium oxide aerosols

    International Nuclear Information System (INIS)

    Sundarajan, A.R.; Mitragotri, D.S.; Mukunda Rao, S.R.

    1982-01-01

    Behavior of aerosol resulting from sodium fires in a closed vessel is investigated and the changes in the particle size distribution of the aerosol due to coagulation and humidity have been studied. The initial mass concentration is in the range of 80 -- 500 mg/m 3 and the relative humidity is varied between 50 to 98%. The initial size of the released aerosol is found to be 0.9 μm. Equilibrium diameters of particles growing in humid air have been computed for various humidity levels using water activity of sodium hydroxide. Both theoretical and experimental results have yielded growth ratios of about 3 at about 95% relative humidity. It is recommended that the computer codes dealing with aerosol coagulation behavior in reactor containment should include an appropriate humidity-growth function. (author)

  1. Relationship between relative humidity and the dew point ...

    African Journals Online (AJOL)

    This research was aimed at determining the relationship between relative humidity and the dew point temperature in Benin City, Edo State, Nigeria. The dew point temperature was approximated from the measured air temperature and relative humidity with the aid of a currently self-designed weather monitoring system.

  2. Bacterial pleomorphism and competition in a relative humidity gradient

    NARCIS (Netherlands)

    de Goffau, Marcus C.; Yang, Xiaomei; van Dijl, Jan Maarten; Harmsen, Hermie J. M.

    The response of different bacterial species to reduced water availability was studied using a simple relative humidity gradient technique. Interestingly, distinct differences in morphology and growth patterns were observed between populations of the same species growing at different relative

  3. Effects of temperature and relative humidity on DNA methylation.

    Science.gov (United States)

    Bind, Marie-Abele; Zanobetti, Antonella; Gasparrini, Antonio; Peters, Annette; Coull, Brent; Baccarelli, Andrea; Tarantini, Letizia; Koutrakis, Petros; Vokonas, Pantel; Schwartz, Joel

    2014-07-01

    Previous studies have found relationships between DNA methylation and various environmental contaminant exposures. Associations with weather have not been examined. Because temperature and humidity are related to mortality even on non-extreme days, we hypothesized that temperature and relative humidity may affect methylation. We repeatedly measured methylation on long interspersed nuclear elements (LINE-1), Alu, and 9 candidate genes in blood samples from 777 elderly men participating in the Normative Aging Study (1999-2009). We assessed whether ambient temperature and relative humidity are related to methylation on LINE-1 and Alu, as well as on genes controlling coagulation, inflammation, cortisol, DNA repair, and metabolic pathway. We examined intermediate-term associations of temperature, relative humidity, and their interaction with methylation, using distributed lag models. Temperature or relative humidity levels were associated with methylation on tissue factor (F3), intercellular adhesion molecule 1 (ICAM-1), toll-like receptor 2 (TRL-2), carnitine O-acetyltransferase (CRAT), interferon gamma (IFN-γ), inducible nitric oxide synthase (iNOS), and glucocorticoid receptor, LINE-1, and Alu. For instance, a 5°C increase in 3-week average temperature in ICAM-1 methylation was associated with a 9% increase (95% confidence interval: 3% to 15%), whereas a 10% increase in 3-week average relative humidity was associated with a 5% decrease (-8% to -1%). The relative humidity association with ICAM-1 methylation was stronger on hot days than mild days. DNA methylation in blood cells may reflect biological effects of temperature and relative humidity. Temperature and relative humidity may also interact to produce stronger effects.

  4. On the distribution of relative humidity in cirrus clouds

    Directory of Open Access Journals (Sweden)

    P. Spichtinger

    2004-01-01

    Full Text Available We have analysed relative humidity statistics from measurements in cirrus clouds taken unintentionally during the Measurement of OZone by Airbus In-service airCraft project (MOZAIC. The shapes of the in-cloud humidity distributions change from nearly symmetric in relatively warm cirrus (warmer than −40°C to considerably positively skew (i.e. towards high humidities in colder clouds. These results are in agreement to findings obtained recently from the INterhemispheric differences in Cirrus properties from Anthropogenic emissions (INCA campaign (Ovarlez et al., 2002. We interprete the temperature dependence of the shapes of the humidity distributions as an effect of the length of time a cirrus cloud needs from formation to a mature equilibrium stage, where the humidity is close to saturation. The duration of this transitional period increases with decreasing temperature. Hence cold cirrus clouds are more often met in the transitional stage than warm clouds.

  5. Cropping Systems and Climate Change in Humid Subtropical Environments

    Directory of Open Access Journals (Sweden)

    Ixchel M. Hernandez-Ochoa

    2018-02-01

    Full Text Available In the future, climate change will challenge food security by threatening crop production. Humid subtropical regions play an important role in global food security, with crop rotations often including wheat (winter crop and soybean and maize (summer crops. Over the last 30 years, the humid subtropics in the Northern Hemisphere have experienced a stronger warming trend than in the Southern Hemisphere, and the trend is projected to continue throughout the mid- and end of century. Past rainfall trends range, from increases up to 4% per decade in Southeast China to −3% decadal decline in East Australia; a similar trend is projected in the future. Climate change impact studies suggest that by the middle and end of the century, wheat yields may not change, or they will increase up to 17%. Soybean yields will increase between 3% and 41%, while maize yields will increase by 30% or decline by −40%. These wide-ranging climate change impacts are partly due to the region-specific projections, but also due to different global climate models, climate change scenarios, single-model uncertainties, and cropping system assumptions, making it difficult to make conclusions from these impact studies and develop adaptation strategies. Additionally, most of the crop models used in these studies do not include major common stresses in this environment, such as heat, frost, excess water, pests, and diseases. Standard protocols and impact assessments across the humid subtropical regions are needed to understand climate change impacts and prepare for adaptation strategies.

  6. Mars Science Laboratory (MSL) - First Results of Relative Humidity Observations

    Science.gov (United States)

    Genzer, Maria; Harri, Ari-Matti; Kemppinen, Osku; Gómez-Elvira, Javier; Renno, Nilton; Savijärvi, Hannu; Schmidt, Walter; Polkko, Jouni; Rodríquez-Manfredi, Jose Antonio; de la Torre Juárez, Manuel; Mischna, Michael; Martín-Torres, Javier; Haukka, Harri; Paz Zorzano-Mier, Maria; Rafkin, Scott; Paton, Mark; MSL Science Team

    2013-04-01

    The Mars Science laboratory (MSL) called Curiosity made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity, and UV measurements. The REMS instrument suite is described at length in [1]. We concentrate on describing the first results from the REMS relative humidity observations and comparison of the measurements with modeling results. The REMS humidity device is provided by the Finnish Meteorological Institute. It is based on polymeric capacitive humidity sensors developed by Vaisala Inc. The humidity device makes use of one transducer electronics section placed in the vicinity of the three (3) humidity sensor heads. The humidity device is mounted on the REMS boom 2 providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The absolute accuracy of the humidity device is temperature dependent, and is of the order of 2% at the temperature range of -30 to -10 °C, and of the order of 10% at the temperature range of -80 to -60 °C. This enables the investigations of atmospheric humidity variations of both diurnal and seasonal scale. The humidity device measurements will have a lag, when a step-wise change in humidity is taking place. This lag effect is increasing with decreasing temperature, and it is of the order of a few hours at the temperature of -75 °C. To compensate for the lag effect we used an algorithm developed by Mäkinen [2]. The humidity observations were validated after tedious efforts. This was needed to compensate for the artifacts of the transducer electronics. The compensation process includes an assumption that the relative humidity at Mars in the temperature range of 0 to -30 °C is about zero. The

  7. High Accuracy Acoustic Relative Humidity Measurement inDuct Flow with Air

    Directory of Open Access Journals (Sweden)

    Cees van der Geld

    2010-08-01

    Full Text Available An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0–12 m/s with an error of ±0.13 m/s, temperature 0–100 °C with an error of ±0.07 °C and relative humidity 0–100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

  8. High accuracy acoustic relative humidity measurement in duct flow with air.

    Science.gov (United States)

    van Schaik, Wilhelm; Grooten, Mart; Wernaart, Twan; van der Geld, Cees

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and relative humidity (RH) instantaneously, by applying two ultrasonic transducers and an array of four temperature sensors. Measurement ranges are: gas velocity of 0-12 m/s with an error of ± 0.13 m/s, temperature 0-100 °C with an error of ± 0.07 °C and relative humidity 0-100% with accuracy better than 2 % RH above 50 °C. Main advantage over conventional humidity sensors is the high sensitivity at high RH at temperatures exceeding 50 °C, with accuracy increasing with increasing temperature. The sensors are non-intrusive and resist highly humid environments.

  9. Short Oligonucleotides Aligned in Stretched Humid Matrix: Secondary DNA Structure in Poly(vinyl alcohol) Environment

    KAUST Repository

    Hanczyc, Piotr; Å kerman, Bjö rn; Nordé n, Bengt

    2012-01-01

    ) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.4 nm) were investigated with respect to structural properties in the gel-like polymer environment. The DNA conformation as a function of relative humidity reveals a strong

  10. Measuring the mechanical behavior of paperboard in a changing humidity environment

    Science.gov (United States)

    Dennis E. Gunderson; John M. Considine

    1986-01-01

    “Both the strength and stability of compressively loaded paperboard are known to be adversely affected by cyclic changes in relative humidity. Current research at the Forest Products Laboratory (FPL) seeks to observe and explain this phenomenon and to develop a simple, practical test to determine allowable "working loads" in cyclicmoisture environments. A new...

  11. Mars Science Laboratory relative humidity observations: Initial results.

    Science.gov (United States)

    Harri, A-M; Genzer, M; Kemppinen, O; Gomez-Elvira, J; Haberle, R; Polkko, J; Savijärvi, H; Rennó, N; Rodriguez-Manfredi, J A; Schmidt, W; Richardson, M; Siili, T; Paton, M; Torre-Juarez, M De La; Mäkinen, T; Newman, C; Rafkin, S; Mischna, M; Merikallio, S; Haukka, H; Martin-Torres, J; Komu, M; Zorzano, M-P; Peinado, V; Vazquez, L; Urqui, R

    2014-09-01

    The Mars Science Laboratory (MSL) made a successful landing at Gale crater early August 2012. MSL has an environmental instrument package called the Rover Environmental Monitoring Station (REMS) as a part of its scientific payload. REMS comprises instrumentation for the observation of atmospheric pressure, temperature of the air, ground temperature, wind speed and direction, relative humidity (REMS-H), and UV measurements. We concentrate on describing the REMS-H measurement performance and initial observations during the first 100 MSL sols as well as constraining the REMS-H results by comparing them with earlier observations and modeling results. The REMS-H device is based on polymeric capacitive humidity sensors developed by Vaisala Inc., and it makes use of transducer electronics section placed in the vicinity of the three humidity sensor heads. The humidity device is mounted on the REMS boom providing ventilation with the ambient atmosphere through a filter protecting the device from airborne dust. The final relative humidity results appear to be convincing and are aligned with earlier indirect observations of the total atmospheric precipitable water content. The water mixing ratio in the atmospheric surface layer appears to vary between 30 and 75 ppm. When assuming uniform mixing, the precipitable water content of the atmosphere is ranging from a few to six precipitable micrometers. Atmospheric water mixing ratio at Gale crater varies from 30 to 140 ppmMSL relative humidity observation provides good dataHighest detected relative humidity reading during first MSL 100 sols is RH75.

  12. NOS CO-OPS Meteorological Data, Relative Humidity, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has Relative Humidity data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). WARNING: These preliminary data have not...

  13. Analysis of air temperature and relative humidity: study of microclimates

    OpenAIRE

    Elis Dener Lima Alves; Marcelo Sacardi Biudes

    2012-01-01

    Understanding the variability of climate elements in time and space is fundamental to the knowledge of the dynamics of microclimate. Thus, the objective was to analyze the variability of air temperature and relative humidity on the Cuiabá campus of the Federal University of Mato Grosso, and, through the clustering technique, to analyze the formation of groups to propose a zoning microclimate in the area study. To this end, collection data of air temperature and relative humidity at 15 points ...

  14. A Trial Intercomparison of Humidity Generators at Extremes of Range Using Relative Humidity Transmitters

    Science.gov (United States)

    Stevens, M.; Benyon, R.; Bell, S. A.; Vicente, T.

    2008-10-01

    In order to effectively implement the Mutual Recognition Arrangement (MRA) of the International Committee for Weights and Measures (CIPM), national metrology institutes (NMIs) are required to support their claims of calibration and measurement capability (CMC) with a quality system compliant with ISO/IEC 17025, and with suitable evidence of participation in key or supplementary comparisons. The CMC review process, both at regional and inter-regional levels, uses criteria that combine the provisions mentioned above, together with additional evidence demonstrating scientific and technical competence of the institutes. For dew-point temperatures, there are key comparisons in progress under the Consultative Committee for Thermometry (CCT) and under the European regional metrology organisation (EUROMET), together with information available on past regional supplementary comparisons. However, for relative humidity there are, to date, no such comparisons available to support CMC entries. This paper presents and discusses the results of a preliminary investigation of the use of relative humidity and temperature transmitters in order to determine their suitability for the intercomparison of standard humidity generators in support of CMC claims for the calibration of relative humidity instruments. The results of a recent bilateral comparison between 2 NMIs at the extremes of the range up to 98%rh at 70 °C, and down to 1%rh at -40 °C are reported. Specific precautions and recommendations on the use of the devices as transfer standards are presented.

  15. Ground calibration of DREAMS-H relative humidity device

    Science.gov (United States)

    Komu, M.; Genzer, M.; Nikkanen, T.; Schmidt, W.; Haukka, H.; Kemppinen, O.; Harri, A.-M.

    2014-04-01

    DREAMS (Dust Characterization, Risk Assessment and Environmental Analyzer on the Martian Surface) instrument suite is to be launched as part of ESA ExoMars 2016/Entry, Descent and Landing Demonstration Module (EDM). DREAMS consists of an environmental package for monitoring temperature, pressure, relative humidity, winds and dust opacity, as well as atmospheric electricity of Martian atmosphere. DREAMS instruments and scientific goals are described in [1]. Here we describe ground calibration of the relative humidity device, DREAMS-H, provided to DREAMS payload by Finnish Meteorological Institute and based on proprietary technology of Vaisala, Inc. Same kind of device is part of REMS instrument package onboard MSL Curiosity Rover [2][3].

  16. Hydration behaviour of synthetic saponite at variable relative humidity

    Indian Academy of Sciences (India)

    Hydration behaviour of synthetic saponite was examined by X-ray powder diffraction simulation at various relative humidities (RH). The basal spacing of the Ca-saponite increased stepwise with increase in RH. The (00) reflections observed reflect single or dual hydration states of smectite. Quasi-rational, intermediate, or ...

  17. Effects of relative humidity on banana fruit drop

    NARCIS (Netherlands)

    Saengpook, C.; Ketsa, S.; Doorn, van W.G.

    2007-01-01

    Commercial ripening of banana fruit occurs at high relative humidity (RH), which prevents browning of damaged skin areas. In experiments with ripening at high RH (94 ± 1%) the individual fruit (fingers) of `Sucrier¿ (Musa acuminata, AA Group) banana exhibited a high rate of drop. The falling off of

  18. A method for high accuracy determination of equilibrium relative humidity

    DEFF Research Database (Denmark)

    Jensen, O.M.

    2012-01-01

    This paper treats a new method for measuring equilibrium relative humidity and equilibrium dew-point temperature of a material sample. The developed measuring device is described – a Dew-point Meter – which by means of so-called Dynamic Dew-point Analysis permits quick and very accurate...

  19. Effect of varying relative humidity on the rancidity of cashew ...

    African Journals Online (AJOL)

    Post harvest deterioration by microbes due to improper storage condition is considered to be the major cause of spoilage and rancidity of most oil-bearing seeds like cashew nuts through lipolytic action of lipase enzyme. Roasted cashew nuts were subjected to four different storage conditions with different relative humidity ...

  20. Statistical analysis of the effects of relative humidity and temperature ...

    African Journals Online (AJOL)

    Meteorological data from the Department of Satellite Application Facility on Climate Monitoring (CMSAF), DWD Germany have been used to study and investigate the effect of relative humidity and temperature on refractivity in twenty six locations grouped into for climatic regions aloft Nigeria (Coastal, Guinea savannah, ...

  1. Pressure and Relative Humidity Measurement Devices for Mars 2020 Rover

    Science.gov (United States)

    Hieta, M.; Genzer, M.; Nikkanen, T.; Haukka, H.; Harri, A.-M.; Polkko, J.; Rodriguez-Manfredi, J. A.

    2017-09-01

    One of the scientific payloads onboard the NASA Mars 2020 rover mission is Mars Environmental Dynamic Analyzer (MEDA): a set of environmental sensors for Mars surface weather measurements. Finnish Meteorological Institute (FMI) provides a pressure measurement device (MEDA PS) and a relative humidity measurement device (MEDA HS) for MEDA.

  2. Using relative humidity to predict spotfire probability on prescribed burns

    Science.gov (United States)

    John R. Weir

    2007-01-01

    Spotfires have and always will be a problem that burn bosses and fire crews will have to contend with on prescribed burns. Weather factors (temperature, wind speed and relative humidity) are the main variables burn bosses can use to predict and monitor prescribed fire behavior. At the Oklahoma State University Research Range, prescribed burns are conducted during...

  3. Effect of Temperature and Relative Humidity on the Growth of ...

    African Journals Online (AJOL)

    were used to determine the temperature effect on the growth of H. fulvum. Maximum growth of H. ... The fungus showed maximum growth at 92.5 and 100% relative humidity. .... recommended that fruits and vegetables should be stored at low ...

  4. Influence of relative humidity on tensile and compressive creep of ...

    African Journals Online (AJOL)

    This paper presents an experimental study on the influence of ambient relative humidity on tensile creep of plain concrete amended with Ground Granulated Blast - furnace Slag and compares it with its influence on compressive creep. Tensile and compressive creep tests were carried out on concrete specimens of 34.49 ...

  5. Radon prevention coating in hot and humid environment

    International Nuclear Information System (INIS)

    Yang Yushan; Dong Faqin; Deng Yuequan; Qu Ruixue

    2013-01-01

    The radon prevention performance of a new self-made radon prevention coating was researched in the radon contamination provided by the releasing radon modules. With coating thickness of 0.8 mm, the radon mitigation efficiency in 1 # radon module concentration is optimal when the addition of defoaming agent is 0.3% (mass fraction). The radon mitigation efficiency increases with the coating thickness when the defoaming agent of 0.3% is added, but the radon mitigation efficiency tends to be stable as the coating thickness is more than 2.0 mm. The radon mitigation efficiency of radon prevention coating appended precipitated barium sulphate decreases obviously, and the addition of ash calcium, white cement and gesso don't decrease radon mitigation efficiency. The addition of white cement and gesso addition affects the radon prevention stability, while radon mitigation efficiency of radon prevention coating with ash calcium keeps a good performance. Under the hot and humid environment, the radon prevention coating still has good radon mitigation efficiency in 2 # radon module concentration. (authors)

  6. Searching for new solutions Humidity measurements in the environments

    Directory of Open Access Journals (Sweden)

    Gianina Creţu

    2008-05-01

    Full Text Available More attention is nowadays being paid to thequality of the air we breathe, resulting in an increasingneed for humidity measurements in the home and officeenvironments. Maintaining the proper level of relativehumidity is also necessary to avoid conditions of extremehumidity condensation in buildings.The facts that construction problems and excessive waterand humidity often go together is well-known around theworld today. Moisture and water damage is a wellknown problem in construction in many countries.Problems of all construction are caused by humidity and50 per cent of all buildings have some kind of moisturerelatedproblems. Growing awareness of percentages suchas these has led to greater attention being paid toconstruction humidity and its measurement throughoutthe world in recent years.This paper presents a condensed review of nowadayshumidity sensors technology, problem implicated andsome modern tendencies.

  7. Why alite stops hydrating below 80% relative humidity

    International Nuclear Information System (INIS)

    Flatt, Robert J.; Scherer, George W.; Bullard, Jeffrey W.

    2011-01-01

    It has been observed that the hydration of cement paste stops when the relative humidity drops below about 80%. A thermodynamic analysis shows that the capillary pressure exerted at that RH shifts the solubility of tricalcium silicate, so that it is in equilibrium with water. This is a reflection of the chemical shrinkage in this system: according to Le Chatelier's principle, since the volume of the products is less than that of the reactants, a negative (capillary) pressure opposes the reaction.

  8. Effect of Temperature and Relative Humidity on the Growth of ...

    African Journals Online (AJOL)

    The effects of temperature and relative humidity on the growth of Helminthosporium fulvum were investigated. Various temperature regimes of 10oC, 15oC, 20oC, 25oC, 30oC, 35oC and 40¢ªC were used to determine the temperature effect on the growth of H. fulvum. Maximum growth of H. fulvum was obtained at 25¢ªC ...

  9. Relative humidity measurements with thermocouple psychrometer and capacitance sensors

    International Nuclear Information System (INIS)

    Mao, Naihsien.

    1991-01-01

    The relative humidity is one of the important hydrological parameters affecting waste package performance. Water potential of a system is defined as the amount of work required to reversibly and isothermally move an infinitesimal quantity of water from a pool of pure water to that system at the same elevation. The thermocouple psychrometer, which acts as a wet-dry bulb instrument based on the Peltier effect, is used to measure water potential. The thermocouple psychrometer works only for relative humidity greater than 94 percent. Other sensors must be used for drier conditions. Hence, the author also uses a Vaisala Humicap, which measures the capacitance change due to relative humidity change. The operation range of the Humicap (Model HMP 135Y) is from 0 to 100 percent relative humidity and up to 160C (320F) in temperature. A psychrometer has three thermocouple junctions. Two copper-constantan junctions serve as reference temperature junctions and the constantan-chromel junction is the sensing junction. Current is passed through the thermocouple causing cooling of the sensing junction by the Peltier effect. When the temperature of the junction is below the dew point, water will condense upon the junction from the air. The Peltier current is discontinued and the thermocouple output is recorded as the temperature of the thermocouple returns to ambient. The temperature changes rapidly toward the ambient temperature until it reaches the wet bulb depression temperature. At this point, evaporation of the water from the junction produces a cooling effect upon the junction that offsets the heat absorbed from the ambient surroundings. This continues until the water is depleted and the thermocouple temperature returns to the ambient temperature (Briscoe, 1984). The datalogger starts to take data roughly at the wet bulb depression temperature

  10. Mouth rinsing improves cycling endurance performance during Ramadan fasting in a hot humid environment.

    Science.gov (United States)

    Che Muhamed, Ahmad Munir; Mohamed, Nazirah Gulam; Ismail, Norjana; Aziz, Abdul Rashid; Singh, Rabindarjeet

    2014-04-01

    This study examined the effect of mouth rinsing during endurance cycling in a hot humid environment (32 °C and 75% relative humidity) on athletes in the Ramadan fasted state. Nine trained adolescent male cyclists completed 3 trials that consisted of a carbohydrate mouth-rinse (CMR), a placebo mouth-rinse (PMR), and a no-rinse (NOR) trial during the last 2 weeks of Ramadan. Each trial consisted of a preloading cycle at 65% peak rate of oxygen consumption for 30 min followed by a 10-km time trial (TT10 km) under hot humid condition. During the CMR and PMR trials, each cyclist rinsed his mouth with 25 mL of the solution for 5 s before expectorating the solution pre-exercise, after 5, 15, and 25 min of the preloading cycle, and 15 s prior to the start of TT10 km. Time to complete the TT10 km was significantly faster in the CMR and PMR trials compared with the NOR trial (12.9 ± 1.7 and 12.6 ± 1.7 vs. 16.8 ± 1.6 min, respectively; p benefits compared with a no-rinse condition on TT10 km performance in acute Ramadan fasted subjects during endurance cycling in a heat stress environment.

  11. Integrated CMOS dew point sensors for relative humidity measurement

    Science.gov (United States)

    Savalli, Nicolo; Baglio, Salvatore; Castorina, Salvatore; Sacco, Vincenzo; Tringali, Cristina

    2004-07-01

    This work deals with the development of integrated relative humidity dew point sensors realized by adopting standard CMOS technology for applications in various fields. The proposed system is composed by a suspended plate that is cooled by exploiting integrated Peltier cells. The cold junctions of the cells have been spread over the plate surface to improve the homogeneity of the temperature distribution over its surface, where cooling will cause the water condensation. The temperature at which water drops occur, named dew point temperature, is a function of the air humidity. Measurement of such dew point temperature and the ambient temperature allows to know the relative humidity. The detection of water drops is achieved by adopting a capacitive sensing strategy realized by interdigited fixed combs, composed by the upper layer of the adopted process. Such a capacitive sensor, together with its conditioning circuit, drives a trigger that stops the cooling of the plate and enables the reading of the dew point temperature. Temperature measurements are achieved by means of suitably integrated thermocouples. The analytical model of the proposed system has been developed and has been used to design a prototype device and to estimate its performances. In such a prototype, the thermoelectric cooler is composed by 56 Peltier cells, made by metal 1/poly 1 junctions. The plate has a square shape with 200 μm side, and it is realized by exploiting the oxide layers. Starting from the ambient temperature a temperature variation of ΔT = 15 K can be reached in 10 ms thus allowing to measure a relative humidity greater than 40%.

  12. Roller compaction: Effect of relative humidity of lactose powder.

    Science.gov (United States)

    Omar, Chalak S; Dhenge, Ranjit M; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

    2016-09-01

    The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes. The powders were stored in a climatic chamber at different relative humidity values ranging from 10% to 80% RH. It was found that the roller compaction behaviour and ribbon properties were different for powders conditioned to different relative humidities. The amount of fines produced, which is undesirable in roller compaction, was found to be different at different relative humidity. The minimum amount of fines produced was found to be for powders conditioned at 20-40% RH. The maximum amount of fines was produced for powders conditioned at 80% RH. This was attributed to the decrease in powder flowability, as indicated by the flow function coefficient ffc and the angle of repose. Particle Image Velocimetry (PIV) was also applied to determine the velocity of primary particles during ribbon production, and it was found that the velocity of the powder during the roller compaction decreased with powders stored at high RH. This resulted in less powder being present in the compaction zone at the edges of the rollers, which resulted in ribbons with a smaller overall width. The relative humidity for the storage of powders has shown to have minimal effect on the ribbon tensile strength at low RH conditions (10-20%). The lowest tensile strength of ribbons produced from lactose 200M and SD was for powders conditioned at 80% RH, whereas, ribbons produced from lactose 21AN at the same condition of 80% RH showed the highest tensile strength. The storage RH range 20-40% was found to be an optimum condition for roll compacting three lactose powders, as it resulted in a minimum amount of fines in the

  13. Influence of relative humidity on radiosensitivity of Aspergillus flavus Link. infecting cocoa beans

    International Nuclear Information System (INIS)

    Amoako-Atta, B.; Odamtten, G.T.; Appiah, V.

    1981-01-01

    The first part of this paper deals with the moisture sorption isotherms of dried cocoa beans under different relative humidities of 55, 65, 75, 85 or 95%. The second part evaluates the effects of relative humidity (RH), initial moisture content (m.c.) of cocoa beans, and different radiation exposure doses (0, 250, 350, 450, 500 or 550 krad) on Aspergillus flavus spore inoculated cocoa beans kept in fixed RH environmental chamber of 75 or 85% RH post-irradiation for forty days. The results discussed suggest that the m.c. of beans increased from an initial level of 6.4% to 7, 7.8 and 8.9% at 55, 65, and 75% respectively, after a storage period of 6-8 days. However, beans stored under 85% or 95% RH continued to absorb moisture from their respective environments indefinitely during the 64-day storage period. Furthermore, the ambient relative humidity to which the beans are subjected before or after irradiation significantly affect the radiosensitivity of toxigenic A. flavus; the differences in such radiosensitivity are influenced by either the available moisture or the initial m.c. of the beans to the inoculum. The authors conclude from their study that high environmental RH increased the radio-resistance of A. flavus spores making it difficult to establish a radiation decontamination level of practical value under a tropical environment with high ambient relative humidity. (author)

  14. Effect of the temperature and relative humidity in dosemeters used for personnel monitoring

    International Nuclear Information System (INIS)

    Antonio Filho, J.

    1982-12-01

    The systematics of the combined effect of temperature and humidity on photographic dosimeters of the type Agfa-Gevaert, Kodak type II, III and the thermoluminescent dosimeters LiF:Mg,Ti (TLD-100, Harshaw), D-CaSO 4 :Dy-0,4 (Teledyne), e CaSO 4 :Dy+NaCl (IPEN), used in personal monitoring in Brazil was investigated, in the temperature range of 20 0 C to 50 0 C and relative humidity of 65% to 95%, in order to determine the best manner of utilization of these detectors in Brazilian climatic conditions. The dosimeters were studied in different forms of packing-sheet such as aluminezed paper and polyethylene. For the determination of the systematics, the dosimeters were irradiated in three conditions: before, during and after of storage in climatic chambers to a maximum period of 60 days. It was found that the dosimetric filmes and thermoluminescent dosimeter CaSO 4 :Dy+NaCl without protection, presented a high dependence to temperature and humidity, and when protected presented good results. Therefore, the best manner of utilization of these monitors in environments with relative humidity and temperature greater them 75% and 30 0 C respectively, is achieved with the protection of aluminized paper. The LiF:Mg,Ti and D+CaSO 4 :Dy-0,4 dosimeters can be utilized in their original form because they presented low dependence with humidity and temperature in the range studied. (Author) [pt

  15. Environment Humidity Effect on the Weight of Carbonized Na-Al-Si Glass Fabrics Recovery after Heating

    International Nuclear Information System (INIS)

    Pentjuss, E; Lusis, A; Gabrusenoks, J; Bajars, G

    2015-01-01

    Na-Al-Si glass fabrics fibres contain Na + ions that diffuse to its surface and along with CO 2 and H 2 O from atmosphere create here the shell of carbonate hydrates. The heating of fabric leads to weight loss by evolving these substances. In this work the results of weight recovery study at room relative humidity (20% – 50%) and elevated humidity (near 70%) of fabrics after its heating at different temperatures (70°C – 150°C) are compared. The experiments shoved the different weight recovery kinetics. The initial exponential stages up to 0.3 h – 0.5 h of the both recoveries are associated with water absorption and differ by its levels. In a case of lower environment humidity the later weight increase are restricted by its value, but at an elevated humidity has a maximum and followed weight increase. The reasons of observed differences are discussed

  16. Testing and ground calibration of DREAMS-H relative humidity device

    Science.gov (United States)

    Genzer, Maria; Hieta, Maria; Nikkanen, Timo; Schmidt, Walter; Kemppinen, Osku; Harri, Ari-Matti; Haukka, Harri

    2015-04-01

    DREAMS (Dust Characterization, Risk Assessment and Environmental Analyzer on the Martian Surface) instrument suite is to be launched as part of the ESA ExoMars 2016/Schiaparelli lander. DREAMS consists of an environmental package for monitoring temperature, pressure, relative humidity, winds and dust opacity, as well as atmospheric electricity of Martian atmosphere. The DREAMS instruments and scientific goals are described in [1]. Here we describe testing and ground calibration of the relative humidity device, DREAMS-H, provided to the DREAMS payload by the Finnish Meteorological Institute and based on proprietary technology of Vaisala, Inc. The same kind of device is part of the REMS instrument package onboard MSL Curiosity Rover [2][3]. DREAMS-H is based on Vaisala Humicap® technology adapted for use in Martian environment by the Finnish Meteorological Institute. The device is very small and lightweighed, with total mass less than 20 g and consuming only 15 mW of power. The Humicap® sensor heads contain an active polymer film that changes its capacitance as function of relative humidity, with 0% to 100% RH measurement range. The dynamic range of the device gets smaller with sensor temperature, being in -70°C approximately 30% of the dynamic range in 0°C [3]. Good-quality relative humidity measurements require knowing the temperature of the environment in which relative humidity is measured. An important part of DREAMS-H calibration was temperature calibration of Vaisala Thermocap® temperature sensors used for housekeeping temperature measurements of the DREAMS-H device. For this, several temperature points in the desired operational range were measured with 0.1°C accuracy traceable to national standards. The main part of humidity calibration of DREAMS-H flight models was done in subzero temperatures in a humidity generator of the Finnish Center of Metrology and Accreditation (MIKES). Several relative humidity points ranging from almost dry to almost wet

  17. Physiological and subjective responses to low relative humidity.

    Science.gov (United States)

    Sunwoo, Yujin; Chou, Chinmei; Takeshita, Junko; Murakami, Motoko; Tochihara, Yutaka

    2006-01-01

    In order to investigate the influence of low relative humidity, we measured saccharin clearance time (SCT), frequency of blinking, heart rate (HR), blood pressure, hydration state of skin, transepidermal water loss (TEWL), recovery sebum level and skin temperature as physiological responses. We asked subjects to judge thermal, dryness and comfort sensations as subjective responses using a rating scale. Sixteen non-smoking healthy male students were selected. The pre-room conditions were maintained at an air temperature (Ta) of 25 degrees C and a relative humidity (RH) of 50%. The test room conditions were adjusted to provide a Ta of 25 degrees C and RH levels of 10%, 30% and 50%.RH had no effect on the activity of the sebaceous gland and on cardiovascular reactions like blood pressure and HR. However, it was obvious that low RH affects SCT, the dryness of the ocular mucosa and the stratum corneum of the skin and causes a decrease in mean skin temperature. Under 30% RH, the eyes and skin become dry, and under 10% RH the nasal mucous membrane becomes dry as well as the eyes and skin, and the mean skin temperature decreases. These findings suggested that to avoid dryness of the eyes and skin, it is necessary to maintain an RH greater than 30%, and to avoid dryness of the nasal mucous membrane, it is necessary to maintain an RH greater than 10%. Subjects felt cold immediately after a change in RH while they had only a slight perception of dryness at the change of humidity.

  18. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Søren Thor, E-mail: stl@nrcwe.dk; Wolkoff, Peder, E-mail: pwo@nrcwe.dk; Hammer, Maria, E-mail: mha@nrcwe.dk; Kofoed-Sørensen, Vivi, E-mail: vks@nrcwe.dk; Clausen, Per Axel, E-mail: pac@nrcwe.dk; Nielsen, Gunnar Damgård, E-mail: gdn@nrcwe.dk

    2013-05-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation.

  19. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    International Nuclear Information System (INIS)

    Larsen, Søren Thor; Wolkoff, Peder; Hammer, Maria; Kofoed-Sørensen, Vivi; Clausen, Per Axel; Nielsen, Gunnar Damgård

    2013-01-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation

  20. Using Relative Humidity Forecasts to Manage Meningitis in the Sahel

    Science.gov (United States)

    Pandya, R. E.; Adams-Forgor, A.; Akweogno, P.; Awine, T.; Dalaba, M.; Dukic, V.; Dumont, A.; Hayden, M.; Hodgson, A.; Hopson, T. M.; Hugonnet, S.; Yoksas, T. C.

    2012-12-01

    Meningitis epidemics in the Sahel occur quasi-regularly and with devastating impact. In 2008, for example, eighty-eight thousand people contracted meningitis and over five thousand died. Until very recently, the protection provided by the only available vaccine was so limited and short-lived that the only practical strategy for vaccination was reactive: waiting until an epidemic occurred in the region and then vaccinating in that region to prevent the epidemic's further growth. Even with that strategy, there were still times when demand outpaced available vaccine. While a new vaccine has recently been developed that is effective and inexpensive enough to be used more broadly and proactively, it is only effective against the strain of bacteria that causes the most common kind of bacterial meningitis. As a result, there will likely be continued need for reactive vaccination strategies. It is widely known that meningitis epidemics in the Sahel occur only in the dry season. Our project investigated this relationship, and several independent lines of evidence demonstrate a robust relationship between the onset of the rainy season, as marked by weekly average relative humidity above 40%, and the end of meningitis epidemics. These lines of evidence include statistical analysis of two years of weekly meningitis and weather data across the Sahel, cross-correlation of ten years of meningitis and weather data in the Upper East region of northern Ghana, and high-resolution weather simulations of past meningitis seasons to interpolate available weather data. We also adapted two techniques that have been successfully used in public health studies: generalized additive models, which have been used to relate air quality and health, and a linearized version of the compartmental epidemics model that has been used to understand MRSA. Based on these multiple lines of evidence, average weekly relative humidity forecast two weeks in advance appears consistently and strongly related to

  1. Diffusion through Pig Gastric Mucin: Effect of Relative Humidity.

    Directory of Open Access Journals (Sweden)

    Anna Runnsjö

    Full Text Available Mucus covers the epithelium found in all intestinal tracts, where it serves as an important protecting barrier, and pharmaceutical drugs administrated by the oral, rectal, vaginal, ocular, or nasal route need to penetrate the mucus in order to reach their targets. Furthermore, the diffusion in mucus as well as the viscosity of mucus in the eyes, nose and throat can change depending on the relative humidity of the surrounding air. In this study we have investigated how diffusion through gels of mucin, the main protein in mucus, is affected by changes in ambient relative humidity (i.e. water activity. Already a small decrease in water activity was found to give rise to a significant decrease in penetration rate through the mucin gel of the antibacterial drug metronidazole. We also show that a decrease in water activity leads to decreased diffusion rate in the mucin gel for the fluorophore fluorescein. This study shows that it is possible to alter transport rates of molecules through mucus by changing the water activity in the gel. It furthermore illustrates the importance of considering effects of the water activity in the mucosa during development of potential pharmaceuticals.

  2. Relation of temperature and humidity to the risk of recurrent gout attacks.

    Science.gov (United States)

    Neogi, Tuhina; Chen, Clara; Niu, Jingbo; Chaisson, Christine; Hunter, David J; Choi, Hyon; Zhang, Yuqing

    2014-08-15

    Gout attack risk may be affected by weather (e.g., because of volume depletion). We therefore examined the association of temperature and humidity with the risk of recurrent gout attacks by conducting an internet-based case-crossover study in the United States (in 2003-2010) among subjects with a diagnosis of gout who had 1 or more attacks during 1 year of follow-up. We examined the association of temperature and humidity over the prior 48 hours with the risk of gout attacks using a time-stratified approach and conditional logistic regression. Among 632 subjects with gout, there was a significant dose-response relationship between mean temperature in the prior 48 hours and the risk of subsequent gout attack (P = 0.01 for linear trend). Higher temperatures were associated with approximately 40% higher risk of gout attack compared with moderate temperatures. There was a reverse J-shaped relationship between mean relative humidity and the risk of gout attacks (P = 0.03 for quadratic trend). The combination of high temperature and low humidity had the greatest association (odds ratio = 2.04, 95% confidence interval: 1.26, 3.30) compared with moderate temperature and relative humidity. Thus, high ambient temperature and possibly extremes of humidity were associated with an increased risk of gout attack, despite the likelihood that individuals are often in climate-controlled indoor environments. © The Author 2014. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Retrieval of relative humidity from CSIR-NLC mobile LIDAR backscatter measurements

    CSIR Research Space (South Africa)

    Tesfaye, M

    2009-09-01

    Full Text Available data was collected over 23 hours. The above data sets were used to determine the retrieved relative humidity and compared with Irene (near to Pretoria) weather balloon humidity measurements. The results of the comparative study are presented...

  4. Temperature and relative humidity dependence of radiochromic film dosimeter response to gamma electron radiation

    DEFF Research Database (Denmark)

    McLaughlin, W.L.; Puhl, J.M.; Miller, A.

    1995-01-01

    on some earlier studies, their response functions have been reported to be dependent on the temperature and relative humidity during irradiation. The present study investigates differences in response over practical ranges of temperature, relative humidity, dose, and for different recent batches of films...... humidity) and should be calibrated under environmental conditions (temperature) at which they will be used routinely....

  5. Effects of acute supplementation of Panax ginseng on endurance running in a hot & humid environment

    Science.gov (United States)

    Ping, Fadzel Wong Chee; Keong, Chen Chee; Bandyopadhyay, Amit

    2011-01-01

    Background & objectives: Athletes in Malaysia need to perform in a hot and humid environment due to the climatic nature of the country. c0 hronic supplementation of Panax ginseng (PG) (a deciduous perennial plant belonging to the Araliaceae family) enhances physical performance. As the ergogenic effect of acute supplementation of PG on endurance performance has not been explored in the Malaysian population especially in a hot and humid condition this study was taken up. Methods: Nine heat adapted recreational runners (age : 25.4 ± 6.9 yr, body mass : 57.6 ± 8.4 kg; body height : 168.3 ± 7.6 cm) were recruited in this placebo-controlled double-blind randomized study. Subjects ingested 200 mg of PG one hour before the exercise test on treadmill at 70 per cent of their VO2max in a laboratory environment of 31 °C and 70 per cent relative humidity. They drank 3 ml/kg body weight of cool water every 20 min during the exercise to prevent adverse effects of dehydration. Blood samples were drawn every 20 min for the analysis of glucose, lactate, insulin and free fatty acids. Oxygen uptake was determined every 20 min while heart rate, body and skin temperatures, and ratings of perceived exertion (RPE) were recorded every 10 min during the trials. Results: Endurance running time to exhaustion did not differ between PG and placebo trials. Heart rate, skin temperature, core body temperature, oxygen uptake, RPE, plasma insulin, glucose, free fatty acid and lactate levels during the endurance exercise did not show any significant differences between the trials. Interpretation & conclusions: We conclude that acute supplementation of 200 mg of PG did not affect the endurance running performance of the heat-adapted male recreational runners in the heat. PMID:21321426

  6. Autogenous Deformation and Change of the Relative Humidity in Silica Fume-Modified Cement Paste

    DEFF Research Database (Denmark)

    Jensen, Ole mejlhede; Hansen, Per Freiesleben

    1996-01-01

    Even during sealed curing and at a constant temperature a hardening cement paste will deform and the relative humidity within its pores will lower. This autogenous deformation and autogenous relative humidity change may be so significant that the cement paste cracks if the deformation is restrained....... This article focuses on the influence of silica fume addition on autogenous deformation and autogenous relative humidity change. Continuous measurement of autogenous deformation and autogenous relative humidity change for more than 1 year and 1« years, respectively, was performed. The investigations show...... thatsilica fume addition markedly increases the autogenous shrinkage as well as the autogenous relative humidity change....

  7. Comparison of techniques for the measurement of skin temperature during exercise in a hot, humid environment

    Directory of Open Access Journals (Sweden)

    Brian K McFarlin

    2014-10-01

    Full Text Available Exercising or working in a hot, humid environment can results in the onset of heat-related illness when an individual’s temperature is not carefully monitored. The purpose of the present study was to compare three techniques (data loggers, thermal imaging, and wired electrodes for the measurement of peripheral (bicep and central (abdominal skin temperature. Young men and women (N=30 were recruited to complete the present study. The three skin temperature measurements were made at 0 and every 10-min during 40-min (60% VO 2 max of cycling in a hot (39±2°C, humid (45±5% RH environment. Data was statistically analyzed using the Bland-Altman method and correlation analysis. For abdominal skin temperature, the Bland-Altman limits of agreement indicated that data loggers (1.5 were a better index of wired than was thermal imaging (3.5, For the bicep skin temperature the limits of agreement was similar between data loggers (1.9 and thermal (1.9, suggesting the both were suitable measurements. We also found that when skin temperature exceeded 35ºC, we observed progressively better prediction between data loggers, thermal imaging, and wired skin sensors. This report describes the potential for the use of data loggers and thermal imaging to be used as alternative measures of skin temperature in exercising, human subjects

  8. Temperature-dependent deliquescence relative humidities and water activities using humidity controlled thermogravimetric analysis with application to malonic acid.

    Science.gov (United States)

    Beyer, Keith D; Schroeder, Jason R; Kissinger, Jared A

    2014-04-03

    We utilize a new experimental technique, humidity-controlled thermogravimetric analysis (HTGA), to determine temperature-dependent deliquescence relative humidities (DRH) and to determine the equilibrium concentration of a solution at a given temperature and relative humidity. To that end, we have investigated the malonic acid/water system determining the DRH and concentration/RH relationship in the temperature range 303-278 K. Excellent agreement is found with literature values for the DRH of malonic acid as a function of temperature and for the concentration/RH relationship at several temperatures. Thus, we extend the DRH and concentration/RH relationship to a broader temperature range and are using the HTGA experiments to investigate other organic acids.

  9. Energy-Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates

    Energy Technology Data Exchange (ETDEWEB)

    Withers, Jr., Charles R. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

    2016-12-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split on seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.

  10. Modeling of humidity-related reliability in enclosures with electronics

    DEFF Research Database (Denmark)

    Hygum, Morten Arnfeldt; Popok, Vladimir

    2015-01-01

    Reliability of electronics that operate outdoor is strongly affected by environmental factors such as temperature and humidity. Fluctuations of these parameters can lead to water condensation inside enclosures. Therefore, modelling of humidity distribution in a container with air and freely exposed...

  11. Relative humidity and activity patterns of Ixodes scapularis (Acari: Ixodidae)

    Science.gov (United States)

    Berger, K.A.; Ginsberg, Howard S.; Gonzalez, L.; Mather, T.N.

    2014-01-01

    Laboratory studies have shown clear relationships between relative humidity (RH) and the activity and survival of Ixodes scapularis Say (blacklegged tick). However, field studies have produced conflicting results. We examined this relationship using weekly tick count totals and hourly RH observations at three field sites, stratified by latitude, within the state of Rhode Island. Records of nymphal tick abundance were compared with several RH-related variables (e.g., RH at time of sampling and mean weekly daytime RH). In total, 825 nymphs were sampled in 2009, a year of greater precipitation, with a weighted average leaf litter RH recorded at time of sampling of 85.22%. Alternatively, 649 nymphs were collected in 2010, a year of relatively low precipitation, and a weighted average RH recorded at time of sampling was 75.51%. Negative binomial regression analysis of tick count totals identified cumulative hours <82% RH threshold as a significant factor observed in both years (2009: P = 0.0037; 2010: P < 0.0001). Mean weekly daytime RH did not significantly predict tick activity in either year. However, mean weekly daytime RH recorded with 1-wk lag before sample date was a significant variable (P = 0.0016) in 2010. These results suggest a lag effect between moisture availability and patterns of tick activity and abundance. Differences in the relative importance of each RH variable between years may have been due to abnormally wet summer conditions in 2009.

  12. Short Oligonucleotides Aligned in Stretched Humid Matrix: Secondary DNA Structure in Poly(vinyl alcohol) Environment

    KAUST Repository

    Hanczyc, Piotr

    2012-04-24

    We report that short, synthetic, double- as well as single-stranded DNA can be aligned in stretched humid poly(vinyl alcohol) (PVA) matrix, and the secondary structure (nucleobase orientation) can be characterized with linear dichroism (LD) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.4 nm) were investigated with respect to structural properties in the gel-like polymer environment. The DNA conformation as a function of relative humidity reveals a strong dependence of helical structure of DNA on PVA hydration level, results of relevance for nanotechnical studies of DNA-based supramolecular systems. Also, the PVA gel could provide possibilities to test models for nucleic acid interactions and distribution in cell contexts, including structural stability of genetic material in the cell and PVA-packaging for gene delivery. A method by which duplex oligonucleotides, with sequences designed to provide specific binding sites, become amenable to polarized-light spectroscopy opens up new possibilities for studying structure in DNA complexes with small adduct molecules as well as proteins. © 2012 American Chemical Society.

  13. Effect of relative humidity on lipid oxidation in freezedried emulsions

    Directory of Open Access Journals (Sweden)

    Chinachoti, P.

    2000-10-01

    Full Text Available Oxidative stability was studied in a freeze-dried emulsion consisting of linoleic acid (LA, Tween-20, sucrose and maltodextrin in the presence of a catalyst (FeSO4/ascorbic acid. Changes in residual LA and conjugated dienes as a function of time were monitored at 0, 32, 43 and 75% relative humidities (RH. Based on GC analyses, LA oxidation was more significant in the surface fraction than the entrapped. The loss of surface oil upon storage may also be due to partial entrapment. However faster oxidation of the surface oil was confirmed by measurement of diene conjugation. Oxidation was more rapid at the lower relative humidities (0 and 32% RH and decreased with increasing RH. At high moisture, physical modifications in the sample were observed, including reduced porosity, structural collapse, reduction of the surface oil and coalescence of oil droplets triggered by sucrose crystallization. These may be responsible for the decreased oxidation. Sucrose crystallization at the higher humidities inhibited oxidation. In addition, while samples with similar glass transition temperature (Tg range behaved differently, samples with different glass transition range showed similar oxidative behaviour. Microstructural changes leading to oil entrapment and oil droplet coalescence were found to be significant, in this case.Se ha estudiado la estabilidad oxidativa en una emulsión liofilizada compuesta de ácido linoleico (LA, Tween-20, sacarosa y maltodextrina en presencia de un catalizador (FeSO4/ácido ascórbico. Los cambios en ácido linoleico remanente (LA y dienos conjugados en función del tiempo fueron monitorizados a humedades relativas (RH del 0, 32, 43 y 75%. Basado en análisis por cromatografía gaseosa, la oxidación de LA fue más significativa en la fracción superficial que en la encapsulada. La pérdida de aceite superficial con el almacenamiento puede deberse también al encapsulado parcial. Sin embargo, la más rápida oxidación del aceite

  14. Results of the Phoenix Relative Humidity Sensor Recalibration

    Science.gov (United States)

    Martinez, G.; Fischer, E.; Renno, N. O.

    2017-12-01

    We show results of the recalibration of the Thermal and Electrical Conductivity Probe (TECP) relative humidity (RH) sensor of the Phoenix Mars lander [Zent et al., 2009]. Due to uncertainties in its pre-flight calibration, which partially overlapped the environmental conditions found at the Phoenix landing site [Tamppari et al., 2010], only the raw, unprocessed output of the TECP RH sensor is available in NASA's Planetary Data System (PDS). The sensor's calibration was revised in 2016 to correct for inaccuracies at the lowest temperatures [Zent et al., 2016], but the new processed RH values were not posted in the PDS. We have been using a spare engineering unit of the TECP to recalibrate the sensor in the full range of Phoenix landing site conditions in the Michigan Mars Environmental Chamber (MMEC) [Fischer et al., 2016]. We compare raw output data of the engineering unit in the MMEC with that of the flight unit from the preflight calibration. We observed that the engineering unit's RH sensor output was shifted to higher values compared to the flight unit's output at the same conditions of temperature and humidity. Based on this shift, we use a translation function that fits the in-situ measurements of the flight unit into the engineering unit output space. To improve the accuracy of this function, we use additional observations corresponding to saturated conditions when near-surface fog was observed [Whiteway et al., 2009], as well as observations around noon when the RH is expected to be below 5%. The entire range of conditions observed on the Martian surface is covered in our recalibration. The raw output of the sensor is used to obtain a new calibration function. This allows us to obtain high-level RH data at Martian polar conditions. The recalibrated data will be posted in the PDS. REFERENCES: Fischer, E., et al. (2016), Astrobiology, 16, 12, doi: 10.1089/ast.2016.1525. Tamppari, L. K., et al. (2010), J. Geophys. Res., 115, E00E17, doi:10.1029/2009JE003415

  15. Proposition of Regression Equations to Determine Outdoor Thermal Comfort in Tropical and Humid Environment

    Directory of Open Access Journals (Sweden)

    Sangkertadi Sangkertadi

    2012-05-01

    Full Text Available This study is about field experimentation in order to construct regression equations of perception of thermalcomfort for outdoor activities under hot and humid environment. Relationships between thermal-comfort perceptions, micro climate variables (temperatures and humidity and body parameters (activity, clothing, body measure have been observed and analyzed. 180 adults, men, and women participated as samples/respondents. This study is limited for situation where wind velocity is about 1 m/s, which touch the body of the respondents/samples. From questionnaires and field measurements, three regression equations have been developed, each for activity of normal walking, brisk walking, and sitting.

  16. Mixing of secondary organic aerosols versus relative humidity

    Science.gov (United States)

    Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin

    2016-01-01

    Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions. PMID:27791066

  17. Mixing of secondary organic aerosols versus relative humidity.

    Science.gov (United States)

    Ye, Qing; Robinson, Ellis Shipley; Ding, Xiang; Ye, Penglin; Sullivan, Ryan C; Donahue, Neil M

    2016-10-24

    Atmospheric aerosols exert a substantial influence on climate, ecosystems, visibility, and human health. Although secondary organic aerosols (SOA) dominate fine-particle mass, they comprise myriad compounds with uncertain sources, chemistry, and interactions. SOA formation involves absorption of vapors into particles, either because gas-phase chemistry produces low-volatility or semivolatile products that partition into particles or because more-volatile organics enter particles and react to form lower-volatility products. Thus, SOA formation involves both production of low-volatility compounds and their diffusion into particles. Most chemical transport models assume a single well-mixed phase of condensing organics and an instantaneous equilibrium between bulk gas and particle phases; however, direct observations constraining diffusion of semivolatile organics into particles containing SOA are scarce. Here we perform unique mixing experiments between SOA populations including semivolatile constituents using quantitative, single-particle mass spectrometry to probe any mass-transfer limitations in particles containing SOA. We show that, for several hours, particles containing SOA from toluene oxidation resist exchange of semivolatile constituents at low relative humidity (RH) but start to lose that resistance above 20% RH. Above 40% RH, the exchange of material remains constant up to 90% RH. We also show that dry particles containing SOA from α-pinene ozonolysis do not appear to resist exchange of semivolatile compounds. Our interpretation is that in-particle diffusion is not rate-limiting to mass transfer in these systems above 40% RH. To the extent that these systems are representative of ambient SOA, we conclude that diffusion limitations are likely not common under typical ambient boundary layer conditions.

  18. Synergistic interactions within disturbed habitats between temperature, relative humidity and UVB radiation on egg survival in a diadromous fish.

    Directory of Open Access Journals (Sweden)

    Michael J H Hickford

    Full Text Available Anthropogenic impacts, including urbanization, deforestation, farming, and livestock grazing have altered riparian margins worldwide. One effect of changes to riparian vegetation is that the ground-level light, temperature, and humidity environment has also been altered. Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, lays eggs almost exclusively beneath riparian vegetation in tidally influenced reaches of rivers. We hypothesized that the survival of these eggs is greatly affected by the micro-environment afforded by vegetation, particularly relating to temperature, humidity and UVB radiation. We experimentally reduced riparian vegetation height and altered shading characteristics, tracked egg survival, and used small ground-level temperature, humidity and UVB sensors to relate survival to ground-level effects around egg masses. The ground-level physical environment was markedly different from the surrounding ambient conditions. Tall dense riparian vegetation modified ambient conditions to produce a buffered temperature regime with constant high relative humidity, generally above 90%, and negligible UVB radiation at ground-level. Where vegetation height was reduced, frequent high temperatures, low humidity, and high UVB irradiances reduced egg survival by up to 95%. Temperature effects on egg survival were probably indirect, through reduced humidity, because developing eggs are known to survive in a wide range of temperatures. In this study, it was remarkable how such small variations in relatively small sites could have such a large effect on egg survival. It appears that modifications to riparian vegetation and the associated changes in the physical conditions of egg laying sites are major mechanisms affecting egg survival. The impacts associated with vegetational changes through human-induced disturbances are complex yet potentially devastating. These effects are particularly important because they

  19. Short term change in relative humidity during the festival of Diwali in India

    Science.gov (United States)

    Ganguly, Nandita D.

    2015-07-01

    The changes in humidity levels during the Diwali festivities have been examined over a period of 13 years at three Indian metro cities: Ahmedabad, New Delhi and Kolkata. A small short term increase in relative humidity even in the absence of transport of humid air from Arabian Sea and Bay of Bengal has been observed. The relative humidity levels were found to be exceeding the ambient levels during night and lying below the ambient levels during morning hours, indicating an increase in the survival rates of viruses responsible for the transmission of viral infections, as well as triggering immune-mediated illnesses such as asthma during Diwali.

  20. The impact of relative humidity and atmospheric pressure on mortality in Guangzhou, China.

    Science.gov (United States)

    Ou, Chun Quan; Yang, Jun; Ou, Qiao Qun; Liu, Hua Zhang; Lin, Guo Zhen; Chen, Ping Yan; Qian, Jun; Guo, Yu Ming

    2014-12-01

    Although many studies have examined the effects of ambient temperatures on mortality, little evidence is on health impacts of atmospheric pressure and relative humidity. This study aimed to assess the impacts of atmospheric pressure and relative humidity on mortality in Guangzhou, China. This study included 213,737 registered deaths during 2003-2011 in Guangzhou, China. A quasi-Poisson regression with a distributed lag non-linear model was used to assess the effects of atmospheric pressure/relative humidity. We found significant effect of low atmospheric pressure/relative humidity on mortality. There was a 1.79% (95% confidence interval: 0.38%-3.22%) increase in non-accidental mortality and a 2.27% (0.07%-4.51%) increase in cardiovascular mortality comparing the 5th and 25th percentile of atmospheric pressure. A 3.97% (0.67%-7.39%) increase in cardiovascular mortality was also observed comparing the 5th and 25th percentile of relative humidity. Women were more vulnerable to decrease in atmospheric pressure and relative humidity than men. Age and education attainment were also potential effect modifiers. Furthermore, low atmospheric pressure and relative humidity increased temperature-related mortality. Both low atmospheric pressure and relative humidity are important risk factors of mortality. Our findings would be helpful to develop health risk assessment and climate policy interventions that would better protect vulnerable subgroups of the population. Copyright © 2014 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  1. SIZE DISTRIBUTION OF SEA-SALT EMISSIONS AS A FUNCTION OF RELATIVE HUMIDITY

    Science.gov (United States)

    This note presents a straightforward method to correct sea-salt-emission particle-size distributions according to local relative humidity. The proposed method covers a wide range of relative humidity (0.45 to 0.99) and its derivation incorporates recent laboratory results on sea-...

  2. Cross-Sensitivity Of Aethalometer Measurements To Relative Humidity

    Energy Technology Data Exchange (ETDEWEB)

    Hannemann, A.; Baltensperger, U.; Weingartner, E.

    2005-03-01

    Absorptive light reduction by atmospheric aerosols is important with respect to their climate forcing. An instrument to measure light absorption is the aethalometer, which is routinely used to measure the attenuation of light transmitted through aerosol-laden fibre filters. Measurements have shown that the condensable gases require a correction for artefacts. We present the first corrections for hydrophobic Palas soot-laden filters for the whole humidity range, enhancing the accuracy of aethalometer datasets. (author)

  3. Building Environment Analysis Based on Temperature and Humidity for Smart Energy Systems

    Directory of Open Access Journals (Sweden)

    Kwang-Ho Won

    2012-10-01

    Full Text Available In this paper, we propose a new HVAC (heating, ventilation, and air conditioning control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment.

  4. Building environment analysis based on temperature and humidity for smart energy systems.

    Science.gov (United States)

    Yun, Jaeseok; Won, Kwang-Ho

    2012-10-01

    In this paper, we propose a new HVAC (heating, ventilation, and air conditioning) control strategy as part of the smart energy system that can balance occupant comfort against building energy consumption using ubiquitous sensing and machine learning technology. We have developed ZigBee-based wireless sensor nodes and collected realistic temperature and humidity data during one month from a laboratory environment. With the collected data, we have established a building environment model using machine learning algorithms, which can be used to assess occupant comfort level. We expect the proposed HVAC control strategy will be able to provide occupants with a consistently comfortable working or home environment.

  5. Relative humidity sensor based on surface plasmon resonance of D-shaped fiber with polyvinyl alcohol embedding Au grating

    Science.gov (United States)

    Yan, Haitao; Han, Daofu; Li, Ming; Lin, Bo

    2017-01-01

    This paper presents the design, fabrication, and characterization of a D-shaped fiber coated with polyvinyl alcohol (PVA) embedding an Au grating-based relative humidity (RH) sensor. The Au grating is fabricated on a D-shaped fiber to match the wave-vector and excite the surface plasmon, and the PVA is embedded in the Au grating as a sensitive cladding film. The refractive index of PVA changes with the ambient humidity. Measurements in a controlled environment show that the RH sensor can achieve a sensitivity of 5.4 nm per relative humidity unit in the RH range from 0% to 70% RH. Moreover, the surface plasmon resonance can be realized and used for RH sensing at the C band of optical fiber communication instead of the visible light band due to the metallic grating microstructure on the D-shaped fiber.

  6. The effect of relative humidity on germination of Sporangia of Phytophthora ramorum

    Science.gov (United States)

    Sporangia of three isolates of P. ramorum representing three different clonal lineages were subjected to relative humidity (RH) levels between 80 and 100% for exposure periods ranging from 1 to 24 h at 20°C in darkness. Airtight snap-lid plastic containers (21.5 x 14.5 x 5 cm) were used as humidity ...

  7. The formation of fire residues associated with hunter-gatherers in humid tropical environments: A geo-ethnoarchaeological perspective

    Science.gov (United States)

    Friesem, David E.; Lavi, Noa; Madella, Marco; Boaretto, Elisabetta; Ajithparsad, P.; French, Charles

    2017-09-01

    Tropical forests have been an important human habitat and played a significant role in early human dispersal and evolution. Likewise, the use of fire, besides being one of the exceptional characteristics of humans, serves as a marker for human evolution. While the use of fire by prehistoric hunter-gatherers is relatively well documented in arid and temperate environments, the archaeological evidence in humid tropical environment is to date very limited. We first review the archaeological evidence for hunter-gatherer use of fire in humid tropical environments and suggest that better understanding of formation processes is required. We present a geo-ethnoarchaeological study from South India, involving ethnography, excavations and laboratory-based analyses in order to build a new framework to study fire residues in humid tropical forests associated with hunter-gatherer's use of fire. Ethnographic observations point to a dynamic and ephemeral use of hearths. Hearths location were dictated by the social and ever-changing social dynamics of the site. The hearths deposited small amount of residues which were later swept on a daily basis, re-depositing ash and charcoal in waste areas and leaving only a microscopic signal in the original location. Particular acidic conditions and intensive biological activity within tropical sediments result in the complete dissolution of ash and bones while favouring the preservation of charcoal and phytoliths. Consequently, the identification of fire residues in humid tropical forests and the reconstruction of the human use of fire must involve multi-proxy microscopic analysis to detect its micro-signatures.

  8. Mycotoxin production in wheat grains by different Aspergilli in relation to different relative humidities and storage periods.

    Science.gov (United States)

    Atalla, Mohamed Mabrouk; Hassanein, Naziha Mohamed; El-Beih, Ahmed Atef; Youssef, Youssef Abdel-ghany

    2003-02-01

    Four different Aspergilli (Aspergillus oryzae, A. parasiticus, A. terreus and A. versicolor) were grown on wheat grains underdifferent degrees of relative humidity 14, 50, 74, 80 and 90%. Samples of wheat grains were taken monthly for a period of six months and examined for mycotoxin production. A. oryzae was found to produce aflatoxins B1, B2, zearalenone, DON and T-2 toxins under elevated degrees of humidity and prolonged periods of storage. A. parasiticus produced aflatoxins B1, G1, NIV, DON and T-2 toxins in high concentrations during a period of not more than three months storage at 14% relative humidity; at an increased level of relative humidity of 74% ochratoxin A, zearalenone and sterigmatocystin were also produced at high levels. The isolate was drastic in toxin production. A. terrus produced toxins at 14% relative humidity (aflatoxin G2 and DON) at levels much higher than any other prevalent degrees of humidity. A. versicolor is highly sensitive to relative humidity and grain moisture content It produced aflatoxins B1, G1, NIV and DON at a relative humidity of 50% and another toxins (aflatoxin G2, ochratoxins A, B and zearalenone) at 74%. The microorganism can be considered a trichothecene producer under suitable relative humidity.

  9. Development of relative humidity models by using optimized neural network structures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-romero, A.; Ortega, J. F.; Juan, J. A.; Tarjuelo, J. M.; Moreno, M. A.

    2010-07-01

    Climate has always had a very important role in life on earth, as well as human activity and health. The influence of relative humidity (RH) in controlled environments (e.g. industrial processes in agro-food processing, cold storage of foods such as fruits, vegetables and meat, or controls in greenhouses) is very important. Relative humidity is a main factor in agricultural production and crop yield (due to the influence on crop water demand or the development and distribution of pests and diseases, for example). The main objective of this paper is to estimate RH [maximum (RHmax), average (RHave), and minimum (RHmin)] data in a specific area, being applied to the Region of Castilla-La Mancha (C-LM) in this case, from available data at thermo-pluviometric weather stations. In this paper Artificial neural networks (ANN) are used to generate RH considering maximum and minimum temperatures and extraterrestrial solar radiation data. Model validation and generation is based on data from the years 2000 to 2008 from 44 complete agroclimatic weather stations. Relative errors are estimated as 1) spatial errors of 11.30%, 6.80% and 10.27% and 2) temporal errors of 10.34%, 6.59% and 9.77% for RHmin, RHmax and RHave, respectively. The use of ANNs is interesting in generating climate parameters from available climate data. For determining optimal ANN structure in estimating RH values, model calibration and validation is necessary, considering spatial and temporal variability. (Author) 44 refs.

  10. Improvement of lithium chloride dew-point hygrometer for direct reading and controlling of relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.Z.; Chu, Y.

    1986-01-01

    The lithium chloride dew-point hygrometer has many advantages over other types of hygrometers. However, it only reads and controls the dew-point temperature of air instead of the relative humidity, which is more important in industry, agriculture, food storage, and hygiene. This paper describes a new hygrometer which is based on the same principle as the lithium chloride dew-point hygrometer, but it can read and control the relative humidity directly. The instrument is quick in response and the ranges of temperature and relative humidity are quite large. Its accuracy is normally within 3% RH and its precision is within 2% RH.

  11. Crystallization speed of salbutamol as a function of relative humidity and temperature.

    Science.gov (United States)

    Zellnitz, Sarah; Narygina, Olga; Resch, Christian; Schroettner, Hartmuth; Urbanetz, Nora Anne

    2015-07-15

    Spray dried salbutamol sulphate and salbutamol base particles are amorphous as a result of spray drying. As there is always the risk of recrystallization of amorphous material, the aim of this work is the evaluation of the temperature and humidity dependent recrystallization of spray dried salbutamol sulphate and base. Therefore in-situ Powder X-ray Diffraction (PXRD) studies of the crystallization process at various temperature (25 and 35 °C) and humidity (60%, 70%, 80%, 90% relative humidity) conditions were performed. It was shown that the crystallization speed of salbutamol sulphate and base is a non-linear function of both temperature and relative humidity. The higher the relative humidity the higher is the crystallization speed. At 60% relative humidity salbutamol base as well as salbutamol sulphate were found to be amorphous even after 12 h, however samples changed optically. At 70% and 90% RH recrystallization of salbutamol base is completed after 3 h and 30 min and recrystallization of salbutamol sulphate after 4h and 1h, respectively. Higher temperature (35 °C) also leads to increased crystallization speeds at all tested values of relative humidity. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Relative Humidity Sensing Properties Of Cu2O Doped ZnO Nanocomposite

    International Nuclear Information System (INIS)

    Pandey, N. K.; Tiwari, K.; Tripathi, A.; Roy, A.; Rai, A.; Awasthi, P.

    2009-01-01

    In this paper we report application of Cu 2 O doped ZnO composite prepared by solid state reaction route as humidity sensor. Pellet samples of ZnO-Cu 2 O nanocrystalline powders with 2, 5 and 10 weight% of Cu 2 O in ZnO have been prepared. Pellets have been annealed at temperatures of 200-500 deg. C and exposed to humidity. It is observed that as relative humidity increases, resistance of the pellet decreases for the humidity from 10% to 90%. Sample with 5% of Cu 2 O doped in ZnO and annealed at 500 deg. C shows best results with sensitivity of 1.50 MΩ/%RH. In this case the hysteresis is low and the reproducibility high, making it the suitable candidate for humidity sensing.

  13. Biases of the MET Temperature and Relative Humidity Sensor (HMP45) Report

    Energy Technology Data Exchange (ETDEWEB)

    Kyrouac, Jenni [Argonne National Lab. (ANL), Argonne, IL (United States); Theisen, Adam [Univ. of Oklahoma, Norman, OK (United States)

    2017-06-30

    The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility Data Quality (DQ) Office was alerted to a potential bias in the surface meteorological instrumentation (MET) temperature when compared with a nearby Mesonet station. This led to an investigation into this problem that was expanded to include many of the other extended facilities (EF) and both the temperature and relative humidity (RH) variables. For this study, the Mesonet was used as the standard reference due to results that showed an increased accuracy in high-humidity environments along with the fact that the Mesonet had previous documented a problem with the HMP45C sensors. Some differences between the sites were taken into account during the analysis: 1. ARM MET sensors were upgraded from an HMP35 to an HMP45 throughout 2007 2. Mesonet switched to aspirated shields in 2009 – To mitigate the differences between aspirated and non-aspirated measurements, data were only analyzed when the wind speed was higher than 3 m/s. This reduced the uncertainty for the non-aspirated measurements from 1.51 ºC to 0.4 ºC. 3. ARM MET is mounted 0.5m higher than the Mesonet station (2.0m versus 1.5m) – This is assumed to have a negligible effect on the differences. 4. Sites were not co-located – For some locations, the distances between sites were as much as 45 km. As part of the investigation into the differences, the Mesonet had reported that the HMP45 sensors had a low-temperature bias in high-humidity environments. This was verified at two different sites where the ARM measurements were compared with the Mesonet measurements. The Mesonet provided redundant temperature measurements from two different sensors at each site. These measurements compared fairly well, while the ARM sensor showed a bias overnight when the humidities were higher. After reviewing the yearly average differences in the data and analyzing the RH data during fog events when we assume it should be

  14. In-situ Air Temperature and Relative Humidity in Greenbelt, MD, 2013-2015

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set describes the temperature and relative humidity at 12 locations around Goddard Space Flight Center in Greenbelt MD at 15 minute intervals between...

  15. models of hourly dry bulb temperature and relative humidity of key

    African Journals Online (AJOL)

    user

    3: Worst cases of MFE for Dry bulb temperature and Relative humidity. Fig. 4: Best cases of ... the Second Joint International Conference of. University of Ilorin, Ilorin, Nigeria and University ... Erbs, D. G., “Models and Applications for Weather.

  16. Diffusion coefficients for unattached decay products of thoron - dependence on ventilation and relative humidity

    International Nuclear Information System (INIS)

    Kotrappa, P.; Bhanti, D.P.; Raghunath, B.

    1976-01-01

    The results of a study of the diffusivity of unattached decay products of thoron with respect to air changes using a recently developed diffusion sampler are reported. The dependence of diffusivity of radon/thoron decay products on relative humidity has also been investigated by measurement of diffusion coefficients in an atmosphere where relative humidities varied from 5 to 90%. Results are shown tabulated. (U.K.)

  17. Effect of relative humidity on migration of BP from paperboard into a food simulant

    DEFF Research Database (Denmark)

    Barnkob, Line Lundbæk; Petersen, Jens Højslev

    In the scientific literature it is obligatory to control and report the test time and temperature applied when testing migration but it is not current practice to either control or report the relative humidity (RH).......In the scientific literature it is obligatory to control and report the test time and temperature applied when testing migration but it is not current practice to either control or report the relative humidity (RH)....

  18. Experimental drying shrinkage of hardened cement pastes as a function of relative humidity

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard; Baroghel, V.B.

    1996-01-01

    The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared.......The results of an experimental study concerning drying shrinkage measured as a function of relative humidity on thin specimens of mature hardened cement pastes are presented. The results obtained at two laboratories are compared....

  19. Resistance of HEPA filter separator materials to humid air--hydrogen fluoride--fluorine environments

    International Nuclear Information System (INIS)

    Weber, C.W.; Petit, G.S.; Woodfin, S.B.

    1977-01-01

    The U. S. Energy Research and Development Administration (ERDA) is interested in the development of a high-efficiency particulate air (HEPA) filter that is resistant to such corrosive reagents as hydrogen fluoride (HF) and fluorine (F 2 ) in air environments of normal relative humidity (about 50% RH). Several types of separator materials are used in the fabrication of commercial filters. The basic types of separator materials are asbestos, Kraft paper, plastic, and aluminum. At the request of the ERDA Division of Operational Safety, the different types of separator materials have been evaluated for their resistance to corrosive attack by HF and F 2 . The separator materials were dynamically tested in the 4-stage multiunit tester located in the Oak Ridge Gaseous Diffusion Plant laboratories. This is the system previously used in the evaluation of the Herty Foundation filter paper samples. Concurrent with the testing of filter media for its resistance to HF and F 2 , another component of the completed filter, the separator, was tested. All samples were exposed to a constant air flow (50% RH) of 32 liters/min, at 100 0 F, containing 900 ppM HF and 300 ppM F 2 . Exposure periods varied from 2 to 1000 h; however, the longer exposures were made only on the stronger candidates. Test results show the plastic and aluminum separator materials to be superior to the other types in resistance to HF and F 2 . The asbestos separators disintegrated after a relatively short exposure time; the Kraft paper types were the next weakest. The Clear Plastic S was the best performer of the plastics tested

  20. Relationship of the moisture content of Finnish wheat flour and relative humidity

    Directory of Open Access Journals (Sweden)

    Yu-Yen Linko

    1968-01-01

    Full Text Available Changes in the moisture content of Finnish commercial wheat flour stored at variable relative humidities, representing the conditions typical of flour storage in Finland, were investigated. It could be shown that flour of 15 % moisture at the time of packing tends to dry considerably during normal storage conditions. Owing to the hysteresis effect, the moisture content of once dried flour is not likely to reach detrimental levels during normal storage, even if the relative humidity would exceed the critical level of 75—80 % for short periods. Minimum warehouse relative humidity was observed during Januay, at which time flour moisture had decreased to 6.7 %. The equilibrium humidity for flour of 15 % original moisture content was found to be about 70 %.

  1. Optical fiber relative humidity sensor based on a FBG with a di-ureasil coating.

    Science.gov (United States)

    Correia, Sandra F H; Antunes, Paulo; Pecoraro, Edison; Lima, Patrícia P; Varum, Humberto; Carlos, Luis D; Ferreira, Rute A S; André, Paulo S

    2012-01-01

    In this work we proposed a relative humidity (RH) sensor based on a Bragg grating written in an optical fiber, associated with a coating of organo-silica hybrid material prepared by the sol-gel method. The organo-silica-based coating has a strong adhesion to the optical fiber and its expansion is reversibly affected by the change in the RH values (15.0-95.0%) of the surrounding environment, allowing an increased sensitivity (22.2 pm/%RH) and durability due to the presence of a siliceous-based inorganic component. The developed sensor was tested in a real structure health monitoring essay, in which the RH inside two concrete blocks with different porosity values was measured over 1 year. The results demonstrated the potential of the proposed optical sensor in the monitoring of civil engineering structures.

  2. Effect of the irradiation temperature and relative humidity on PVG dosifilm

    International Nuclear Information System (INIS)

    Jia Haishun; Chen Wenxiu; Shen Yuxin

    1999-01-01

    The effect of environmental factors, such as irradiation temperature and relative humidity, on the PVG dosifilm irradiated by EB was tested. Experiments show that the temperature coefficient of irradiated PVG dosifilm was 0.008 deg. C -1 from 20 deg. C to 55 deg. C, and the humidity coefficient was 0.006 per r.h. (%) from r.h. 0% to 76%. The PVG dosifilm can be used as a routine dosimeter for dose measurement for low-energy EB processing. The absorbed dose values for various irradiation temperature and humidity can be corrected based on experimental data. (author)

  3. Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates.

    Science.gov (United States)

    Csavina, Janae; Field, Jason; Félix, Omar; Corral-Avitia, Alba Y; Sáez, A Eduardo; Betterton, Eric A

    2014-07-15

    Atmospheric particulate have deleterious impacts on human health. Predicting dust and aerosol emission and transport would be helpful to reduce harmful impacts but, despite numerous studies, prediction of dust events and contaminant transport in dust remains challenging. In this work, we show that relative humidity and wind speed are both determinants in atmospheric dust concentration. Observations of atmospheric dust concentrations in Green Valley, AZ, USA, and Juárez, Chihuahua, México, show that PM10 concentrations are not directly correlated with wind speed or relative humidity separately. However, selecting the data for high wind speeds (>4m/s at 10 m elevation), a definite trend is observed between dust concentration and relative humidity: dust concentration increases with relative humidity, reaching a maximum around 25% and it subsequently decreases with relative humidity. Models for dust storm forecasting may be improved by utilizing atmospheric humidity and wind speed as main drivers for dust generation and transport. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Tapered Fiber Coated with Hydroxyethyl Cellulose/Polyvinylidene Fluoride Composite for Relative Humidity Sensor

    Directory of Open Access Journals (Sweden)

    M. Z. Muhammad

    2013-01-01

    Full Text Available A simple relative humidity (RH sensor is demonstrated using a tapered fiber coated with hydroxyethyl cellulose/polyvinylidene fluoride (HEC/PVDF composite as a probe. This coating acts as an inner cladding whose refractive index decreases with the rise in humidity and thus allows more light to be transmitted in humid state. A difference of up to 0.89 dB of the transmitted optical power is observed when RH changes from 50% to 80% in case of the silica fiber probe. The proposed sensor has a sensitivity of about 0.0228 dB/%RH with a slope linearity of more than 99.91%. In case of the plastic optical fiber (POF probe, the output voltage of the sensor increases linearly with a sensitivity of 0.0231 mV/%RH and a linearity of more than 99.65% as the relative humidity increases from 55% to 80%.

  5. influence of relative humidity on tensile and compressive creep

    African Journals Online (AJOL)

    HOD

    creep specimens were cured in a fog room at 99% RH and 20 oC until the beginning of the tests in the controlled environment creep rooms. To eliminate the influence of stress level and age of loading, a uniform stress of 12.26MPa was used for the three compressive creep tests and the specimens were all loaded at the.

  6. Technique for the measurement of dimensional changes of natural microfibril materials under variable humidity environments

    International Nuclear Information System (INIS)

    Lee, Jung Myoung; Heitmann, John A.; Pawlak, Joel J.

    2007-01-01

    An algorithm was developed to analyze the dimensions of line scan data of step-shaped disconitunities acquired with an atomic force microscope. The effect of a number of AFM parameters on the quantitative imaging of step features was discussed. Quantitiative imaging using AFM was shown to be very reproducible as five successive scans of a standard step height grating produced less than 3% variation in measured parameters. A cellulose microfibril, called cellulose aggregate fibril (CAF), with dimensions of ∼50,000 nm x 2000 nm x 300 nm derived from papermaking fibers was scanned under cyclic relative humdity conditions with the relative humidity starting at 50% then raising to 80% followed by a decrease in the relative humidity to 28%. Changes in the width of the CAF were weakly correlated with changes in the relative humdity, while changes in the height and area of the CAF were positively correlated with the relative humdity. The length of the CAF was negatively correlated with the given relative humdity cycle. These findings have significant implications in paper dimensional stability and the engineering of cellulose micro and nano-fiber composites

  7. Standard Test Methods for Photovoltaic Modules in Cyclic Temperature and Humidity Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 These test methods provide procedures for stressing photovoltaic modules in simulated temperature and humidity environments. Environmental testing is used to simulate aging of module materials on an accelerated basis. 1.2 Three individual environmental test procedures are defined by these test methods: a thermal cycling procedure, a humidity-freeze cycling procedure, and an extended duration damp heat procedure. Electrical biasing is utilized during the thermal cycling procedure to simulate stresses that are known to occur in field-deployed modules. 1.3 These test methods define mounting methods for modules undergoing environmental testing, and specify parameters that must be recorded and reported. 1.4 These test methods do not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of these test methods. 1.5 Any of the individual environmental tests may be performed singly, or may be combined into a test sequence with other environmental or non-envir...

  8. A vantage from space can detect earlier drought onset: an approach using relative humidity.

    Science.gov (United States)

    Farahmand, Alireza; AghaKouchak, Amir; Teixeira, Joao

    2015-02-25

    Each year, droughts cause significant economic and agricultural losses across the world. The early warning and onset detection of drought is of particular importance for effective agriculture and water resource management. Previous studies show that the Standard Precipitation Index (SPI), a measure of precipitation deficit, detects drought onset earlier than other indicators. Here we show that satellite-based near surface air relative humidity data can further improve drought onset detection and early warning. This paper introduces the Standardized Relative Humidity Index (SRHI) based on the NASA Atmospheric Infrared Sounder (AIRS) observations. The results indicate that the SRHI typically detects the drought onset earlier than the SPI. While the AIRS mission was not originally designed for drought monitoring, we show that its relative humidity data offers a new and unique avenue for drought monitoring and early warning. We conclude that the early warning aspects of SRHI may have merit for integration into current drought monitoring systems.

  9. Climate risk assessment in museums : degradation risks determined from temperature and relative humidity data

    NARCIS (Netherlands)

    Martens, M.H.J.

    2012-01-01

    The main subject of this thesis is the determination of climate risks to objects in museums on the basis of measured and/or simulated temperature and relative humidity data. The focus is on the quantification of climate related risks for the preservation quality of indoor climate in Dutch museums.

  10. Development of data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector

    International Nuclear Information System (INIS)

    Sahu, S.; Sahu, P.K.; Bhuyan, M.R.; Biswas, S.; Mohanty, B.

    2014-01-01

    At IoP-NISER an initiative has been taken to build and test micro-pattern gas detector such as Gas Electron Multiplier (GEM) for several upcoming High-Energy Physics (HEP) experiment projects. Temperature (t), atmospheric pressure (p) and relative humidity (RH) monitor and recording is very important for gas filled detector development. A data logger to monitor and record the ambient parameters such as temperature, relative humidity and pressure has been developed. With this data logger continuous recording of t, p, RH and time stamp can be done with a programmable sampling interval. This data is necessary to correct the gain of a gas filled detector

  11. Heat strain evaluation of overt and covert body armour in a hot and humid environment.

    Science.gov (United States)

    Pyke, Andrew J; Costello, Joseph T; Stewart, Ian B

    2015-03-01

    The aim of this study was to elucidate the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. Eight healthy males walked on a treadmill for 120 min at 22% of their heart rate reserve in a climate chamber simulating 31 °C (60%RH) wearing either no armour (control), overt or covert PBA in addition to a security guard uniform, in a randomised controlled crossover design. No significant difference between conditions at the end of each trial was observed in core temperature, heart rate or skin temperature (P > 0.05). Covert PBA produced a significantly greater amount of body mass change (-1.81 ± 0.44%) compared to control (-1.07 ± 0.38%, P = 0.009) and overt conditions (-1.27 ± 0.44%, P = 0.025). Although a greater change in body mass was observed after the covert PBA trial; based on the physiological outcome measures recorded, the heat strain encountered while wearing lightweight, non-military overt or covert PBA was negligible compared to no PBA. The wearing of bullet proof vests or body armour is a requirement of personnel engaged in a wide range of occupations including police, security, customs and even journalists in theatres of war. This randomised controlled crossover study is the first to examine the thermophysiological effects of wearing lightweight non-military overt and covert personal body armour (PBA) in a hot and humid environment. We conclude that the heat strain encountered while wearing both overt and covert lightweight, non-military PBA was negligible compared to no PBA. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  12. Neutron diffraction for studying the influence of the relative humidity on the carbonation process of cement pastes

    International Nuclear Information System (INIS)

    Galan, I; Andrade, C; Castellote, M; Rebolledo, N; Sanchez, J; Toro, L; Puente, I; Campo, J; Fabelo, O

    2011-01-01

    The effect of humidity on hydrated cement carbonation has been studied by means of in-situ neutron diffraction measurements. The evolution of the main crystalline phases in the bulk of the sample, portlandite and calcite, has been monitored during the process. Data obtained from neutron diffraction allow the quantification of the phases involved. The results highlight the great influence of humidity on carbonation. At very low humidity there are almost no changes. Between 53 and 75% relative humidity, portlandite decrease and calcite increase data can be fitted to exponential decay functions. At very high humidity portlandite remains nearly constant while calcite increases slightly with time, almost linearly.

  13. A critical assessment of the JULES land surface model hydrology for humid tropical environments

    Science.gov (United States)

    Zulkafli, Z.; Buytaert, W.; Onof, C.; Lavado, W.; Guyot, J. L.

    2013-03-01

    Global land surface models (LSMs) such as the Joint UK Land Environment Simulator (JULES) are originally developed to provide surface boundary conditions for climate models. They are increasingly used for hydrological simulation, for instance to simulate the impacts of land use changes and other perturbations on the water cycle. This study investigates how well such models represent the major hydrological fluxes at the relevant spatial and temporal scales - an important question for reliable model applications in poorly understood, data-scarce environments. The JULES-LSM is implemented in a 360 000 km2 humid tropical mountain basin of the Peruvian Andes-Amazon at 12-km grid resolution, forced with daily satellite and climate reanalysis data. The simulations are evaluated using conventional discharge-based evaluation methods, and by further comparing the magnitude and internal variability of the basin surface fluxes such as evapotranspiration, throughfall, and surface and subsurface runoff of the model with those observed in similar environments elsewhere. We find reasonably positive model efficiencies and high correlations between the simulated and observed streamflows, but high root-mean-square errors affecting the performance in smaller, upper sub-basins. We attribute this to errors in the water balance and JULES-LSM's inability to model baseflow. We also found a tendency to under-represent the high evapotranspiration rates of the region. We conclude that strategies to improve the representation of tropical systems to be (1) addressing errors in the forcing and (2) incorporating local wetland and regional floodplain in the subsurface representation.

  14. Estimating relations between temperature, relative humidity as independed variables and selected water quality parameters in Lake Manzala, Egypt

    Directory of Open Access Journals (Sweden)

    Gehan A.H. Sallam

    2018-03-01

    Full Text Available In Egypt, Lake Manzala is the largest and the most productive lake of northern coastal lakes. In this study, the continuous measurements data of the Real Time Water Quality Monitoring stations in Lake Manzala were statistically analyzed to measure the regional and seasonal variations of the selected water quality parameters in relation to the change of air temperature and relative humidity. Simple formulas are elaborated using the DataFit software to predict the selected water quality parameters of the Lake including pH, Dissolved Oxygen (DO, Electrical Conductivity (EC, Total Dissolved Solids (TDS, Turbidity, and Chlorophyll as a function of air temperature, relative humidity and quantities and qualities of the drainage water that discharge into the lake. An empirical positive relation was found between air temperature and the relative humidity and pH, EC and TDS and negative relation with DO. There is no significant effect on the other two parameters of turbidity and chlorophyll.

  15. Laboratory Studies of Temperature and Relative Humidity Dependence of Aerosol Nucleation during the TANGENT 2017 IOP Study

    Science.gov (United States)

    Ouyang, Q.; Tiszenkel, L.; Stangl, C. M.; Krasnomowitz, J.; Johnston, M. V.; Lee, S.

    2017-12-01

    In this poster, we will present recent measurements of temperature and relative humidity dependence of aerosol nucleation of sulfuric acid under the conditions representative of the ground level to the free troposphere. Aerosol nucleation is critically dependent on temperature, but the current global aerosol models use nucleation algorithms that are independent of temperature and relative humidity due to the lack of experimental data. Thus, these models fail to simulate nucleation in a wide range of altitude and latitude conditions. We are currently conducting the Tandem Aerosol Nucleation and Growth Environment Tube (TANGENT) the intense observation period (IOP) experiments to investigate the aerosol nucleation and growth properties independently, during nucleation and growth. Nucleation takes place from sulfuric acid, water and some base compounds in a fast flow nucleation tube (FT-1). Nucleation precursors are detected with two chemical ionization mass spectrometers (CIMS) and newly nucleated particles are measured with a particle size magnifier (PSM) and a scanning mobility particle sizers (SMPS). Then these particles grow further in the second flow tube (FT-2) in the presence of oxidants of biogenic organic compounds. Chemical compositions of grown particles are further analyzed with a nano-aerosol mass spectrometer (NAMS). Our experimental results will provide a robust algorithm for aerosol nucleation and growth rates as a function of temperature and relative humidity.

  16. Effect of relative humidity and temperature control on in-cabin thermal comfort state: Thermodynamic and psychometric analyses

    International Nuclear Information System (INIS)

    Alahmer, A.; Omar, M.A.; Mayyas, A.; Dongri, Shan

    2011-01-01

    This manuscript discusses the effect of manipulating the Relative Humidity RH of in-cabin environment on the thermal comfort and human occupants' thermal sensation. The study uses thermodynamic and psychometric analyses, to incorporate the effect of changing RH along with the dry bulb temperature on human comfort. Specifically, the study computes the effect of changing the relative humidity on the amount of heat rejected from the passenger compartment and the effect of relative humidity on occupants comfort zone. A practical system implementation is also discussed in terms of an evaporative cooler design. The results show that changing the RH along with dry bulb temperature inside vehicular cabins can improve the air conditioning efficiency by reducing the heat removed while improving the Human comfort sensations as measured by the Predicted Mean Value PMV and the Predicted Percentage Dissatisfied PPD indices. - Highlights: → Investigates the effect of controlling the RH and dry bulb temperature on in-cabin thermal comfort and sensation. → Conducts the thermodynamic and psychometric analyses for changing the RH and temperature for in-cabin air conditioning. → Discusses a possible system implementation through an evaporative cooler design.

  17. Humidity Sensing in Drosophila.

    Science.gov (United States)

    Enjin, Anders; Zaharieva, Emanuela E; Frank, Dominic D; Mansourian, Suzan; Suh, Greg S B; Gallio, Marco; Stensmyr, Marcus C

    2016-05-23

    Environmental humidity influences the fitness and geographic distribution of all animals [1]. Insects in particular use humidity cues to navigate the environment, and previous work suggests the existence of specific sensory mechanisms to detect favorable humidity ranges [2-5]. Yet, the molecular and cellular basis of humidity sensing (hygrosensation) remains poorly understood. Here we describe genes and neurons necessary for hygrosensation in the vinegar fly Drosophila melanogaster. We find that members of the Drosophila genus display species-specific humidity preferences related to conditions in their native habitats. Using a simple behavioral assay, we find that the ionotropic receptors IR40a, IR93a, and IR25a are all required for humidity preference in D. melanogaster. Yet, whereas IR40a is selectively required for hygrosensory responses, IR93a and IR25a mediate both humidity and temperature preference. Consistent with this, the expression of IR93a and IR25a includes thermosensory neurons of the arista. In contrast, IR40a is excluded from the arista but is expressed (and required) in specialized neurons innervating pore-less sensilla of the sacculus, a unique invagination of the third antennal segment. Indeed, calcium imaging showed that IR40a neurons directly respond to changes in humidity, and IR40a knockdown or IR93a mutation reduced their responses to stimuli. Taken together, our results suggest that the preference for a specific humidity range depends on specialized sacculus neurons, and that the processing of environmental humidity can happen largely in parallel to that of temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Air humidity requirements for human comfort

    DEFF Research Database (Denmark)

    Toftum, Jørn; Fanger, Povl Ole

    1999-01-01

    level near 100% rh. For respiratory comfort are the requirements much more stringent and results in lower permissible indoor air humidities. Compared with the upper humidity limit specified in existing thermal comfort standards, e.g. ASHRAE Addendum 55a, the humidity limit based on skin humidity......Upper humidity limits for the comfort zone determined from two recently presented models for predicting discomfort due to skin humidity and insufficient respiratory cooling are proposed. The proposed limits are compared with the maximum permissible humidity level prescribed in existing standards...... for the thermal indoor environment. The skin humidity model predicts discomfort as a function of the relative humidity of the skin, which is determined by existing models for human heat and moisture transfer based on environmental parameters, clothing characteristics and activity level. The respiratory model...

  19. Sporulation of Bremia lactucae affected by temperature, relative humidity, and wind in controlled conditions

    NARCIS (Netherlands)

    Su, H.; Bruggen, van A.H.C.; Subbarao, K.V.; Scherm, H.

    2004-01-01

    The effects of temperature (5 to 25degreesC), relative humidity (81 to 100%), wind speed (0 to 1.0 in s(-1)), and their interactions on sporulation of Bremia lactucae on lettuce cotyledons were investigated in controlled conditions. Sporulation was affected significantly (P <0.0001) by

  20. Cluster size influence on the survivability of Rhipicephalus Boophilus microplus larvae under low relative humidity stress

    Science.gov (United States)

    Low relative humidity (RH) levels (=63%) have been previously shown to be a determining factor in the survival of southern cattle fever tick, Rhipicephalus microplus, larvae, regardless of temperature. Supporting this observation, large larval clusters can retain more water than isolated larvae. Th...

  1. The role of absorbent building materials in moderating changes of relative humidity

    DEFF Research Database (Denmark)

    Padfield, Tim

    The problem studied in this work is, how porous, absorbent materials surroundning or placed in a room influence the relative humidity of the room. This is of interest in designing precautions and machinery to monitor the indoor climate in museums and dwelling rooms. - A novel technique for the in...

  2. The relative influence of body characteristics on humid heat stress response

    NARCIS (Netherlands)

    Havenith, G.; Luttikholt, V. G.; Vrijkotte, T. G.

    1995-01-01

    The present study was designed to determine the relative importance of individual characteristics such as maximal oxygen uptake (VO2max), adiposity, DuBois body surface area (AD), surface to mass ratio (AD: mass) and body mass, for the individual's reaction to humid heat stress. For this purpose 27

  3. Influence of temperature on autogenous deformation and relative humidity change in hardening cement paste

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben

    1999-01-01

    This paper deals with autogenous deformation and autogenous relative humidity change (RH change) in hardening cement paste. Theoretical considerations and experimental data are presented, which elucidate the influence of temperature on these properties. This is an important subject in the control...

  4. The effect of relative humidity on output performance of inclined and ...

    African Journals Online (AJOL)

    The set-up of 70 Watts solar panel was inclined stationary at 150 for maximum solar reception while the set-up of 80 Watts solar panel had automatic solar tracker for effective capturing of solar radiation. For 70 Watts solar panel, the maximum power output of 59.99 Watt was obtained when the relative humidity was 30%.

  5. High accuracy acoustic relative humidity measurement in duct flow with air

    NARCIS (Netherlands)

    Schaik, van W.; Grooten, M.H.M.; Wernaart, T.; Geld, van der C.W.M.

    2010-01-01

    An acoustic relative humidity sensor for air-steam mixtures in duct flow is designed and tested. Theory, construction, calibration, considerations on dynamic response and results are presented. The measurement device is capable of measuring line averaged values of gas velocity, temperature and

  6. Uncertainties in downscaled relative humidity for a semi-arid region ...

    Indian Academy of Sciences (India)

    variables are extracted from the (1) National Centers for Environmental Prediction ... and (2) simulations of the third generation Canadian Coupled Global Climate ... Ef, MAE and P. Cumulative distribution functions were prepared from the ... Climate change; downscaling; hydroclimatology; relative humidity; multi-step linear ...

  7. Relative Humidity Sensor Based on No-Core Fiber Coated by Agarose-Gel Film

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2017-10-01

    Full Text Available A relative humidity (RH sensor based on single-mode–no-core–single-mode fiber (SNCS structure is proposed and experimentally demonstrated. The agarose gel is coated on the no-core fiber (NCF as the cladding, and multimode interference (MMI occurs in the SNCS structure. The transmission spectrum of the sensor is modulated at different ambient relative humidities due to the tunable refractive index property of the agarose gel film. The relative humidity can be measured by the wavelength shift and intensity variation of the dip in the transmission spectra. The humidity response of the sensors, coated with different concentrations and coating numbers of the agarose solution, were experimentally investigated. The wavelength and intensity sensitivity is obtained as −149 pm/%RH and −0.075 dB/%RH in the range of 30% RH to 75% RH, respectively. The rise and fall time is tested to be 4.8 s and 7.1 s, respectively. The proposed sensor has a great potential in real-time RH monitoring.

  8. Building America Case Study: Energy Efficient Management of Mechanical Ventilation and Relative Humidity in Hot-Humid Climates, Cocoa, Florida

    Energy Technology Data Exchange (ETDEWEB)

    2017-01-01

    In hot and humid climates, it is challenging to energy-efficiently maintain indoor RH at acceptable levels while simultaneously providing required ventilation, particularly in high performance low cooling load homes. The fundamental problem with solely relying on fixed capacity central cooling systems to manage moisture during low sensible load periods is that they are oversized for cooler periods of the year despite being 'properly sized' for a very hot design cooling day. The primary goals of this project were to determine the impact of supplementing a central space conditioning system with 1) a supplemental dehumidifier and 2) a ductless mini-split on seasonal energy use and summer peak power use as well as the impact on thermal distribution and humidity control inside a completely furnished lab home that was continuously ventilated in accordance with ASHRAE 62.2-2013.

  9. Seasonal Variations of Indoor Microbial Exposures and Their Relation to Temperature, Relative Humidity, and Air Exchange Rate

    DEFF Research Database (Denmark)

    Frankel, Mika; Bekö, Gabriel; Timm, Michael

    2012-01-01

    with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total...... inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m3) and were lowest in winter (median, 26 CFU/m3). Indoor...... of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly...

  10. Comparison of axillary and rectal temperatures for healthy Beagles in a temperature- and humidity-controlled environment.

    Science.gov (United States)

    Mathis, Justin C; Campbell, Vicki L

    2015-07-01

    To compare axillary and rectal temperature measurements obtained with a digital thermometer for Beagles in a temperature- and humidity-controlled environment. 26 healthy Beagles (17 sexually intact males and 9 sexually intact females). Dogs were maintained in a temperature- and humidity-controlled environment for 56 days before rectal and axillary temperatures were measured. Axillary and rectal temperatures were obtained in triplicate for each dog by use of a single commercially available manufacturer-calibrated digital thermometer. Mean rectal and axillary temperatures of Beagles maintained in a temperature- and humidity-controlled environment were significantly different, with a median ± SD difference of 1.4° ± 0.15°C (range, 0.7° to 2.1°C). Mean rectal and axillary temperatures were 38.7°C (range, 37.6° to 39.5°C) and 37.2°C (range, 36.6° to 38.3°C), respectively. Results of this study indicated that the historical reference of a 0.55°C gradient between rectal and axillary temperatures that has been clinically used for veterinary patients was inaccurate for healthy Beagles in a temperature- and humidity-controlled environment. Rectal and axillary temperatures can be measured in veterinary patients. Reliable interpretation of axillary temperatures may accommodate patient comfort and reduce patient anxiety when serial measurement of temperatures is necessary. Further clinical studies will be needed.

  11. Cultivar Differences in Plant Transpiration Rate at High Relative Air Humidity Are Not Related to Genotypic Variation in Stomatal Responsiveness

    DEFF Research Database (Denmark)

    Gebraegziabher, Habtamu Giday; Kjær, Katrine Heinsvig; Ottosen, Carl-Otto

    2015-01-01

    Plants grown at high relative air humidity (RH) often show disturbed water relations due to less responsive stomata. The attenuation of stomatal responsiveness as a result of high RH during leaf expansion depends on the cultivar. We hypothesized that tolerant cultivars to high RH experience a low...

  12. Nucleation and Crystal Growth of Organic-Inorganic Lead Halide Perovskites under Different Relative Humidity.

    Science.gov (United States)

    Gao, Hao; Bao, Chunxiong; Li, Faming; Yu, Tao; Yang, Jie; Zhu, Weidong; Zhou, Xiaoxin; Fu, Gao; Zou, Zhigang

    2015-05-06

    Organic-inorganic lead halide perovskite compounds are very promising materials for high-efficiency perovskite solar cells. But how to fabricate high-quality perovksite films under controlled humidity conditions is still an important issue due to their sensitivity to moisture. In this study, we investigated the influence of ambient humidity on crystallization and surface morphology of one-step spin-coated perovskite films, as well as the performance of solar cells based on these perovskite films. On the basis of experimental analyses and thin film growth theory, we conclude that the influence of ambient humidity on nucleation at spin-coating stage is quite different from that on crystal growth at annealing stage. At the spin-coating stage, high nucleation density induced by high supersaturation prefers to appear under anhydrous circumstances, resulting in layer growth and high coverage of perovskite films. But at the annealing stage, the modest supersaturation benefits formation of perovskite films with good crystallinity. The films spin-coated under low relative humidity (RH) followed by annealing under high RH show an increase of crystallinity and improved performance of devices. Therefore, a mechanism of fast nucleation followed by modest crystal growth (high supersaturation at spin-coating stage and modest supersaturation at annealing stage) is suggested in the formation of high-quality perovskite films.

  13. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

    Science.gov (United States)

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  14. Physiological and subjective responses to low relative humidity in young and elderly men.

    Science.gov (United States)

    Sunwoo, Yujin; Chou, Chinmei; Takeshita, Junko; Murakami, Motoko; Tochihara, Yutaka

    2006-05-01

    In order to compare the physiological and the subjective responses to low relative humidity of elderly and young men, we measured saccharin clearance time (SCT), frequency of blinking, hydration state of the skin, transepidermal water loss (TEWL), sebum level recovery and skin temperatures as physiological responses. We asked subjects to evaluate thermal, dryness and comfort sensations as subjective responses using a rating scale. Eight non-smoking healthy male students (21.7+/-0.8 yr) and eight non-smoking healthy elderly men (71.1+/-4.1 yr) were selected. The pre-room conditions were maintained at an air temperature (Ta) of 25 degrees C and a relative humidity (RH) of 50%. The test-room conditions were adjusted to provide 25 degrees C Ta and RH levels of 10%, 30% and 50%. RH had no effect on the activity of the sebaceous gland or change of mean skin temperature. SCT of the elderly group under 10% RH was significantly longer than that of the young group. In particular, considering the SCT change, the nasal mucous membrane seems to be affected more in the elderly than in the young in low RH. Under 30% RH, the eyes and skin become dry, and under 10% RH the nasal mucous membrane becomes dry as well as the eyes and skin. These findings suggested that to avoid dryness of the eyes and skin, it is necessary to maintain greater than 30% RH, and to avoid dryness of the nasal mucous membrane, it is necessary to maintain greater than 10% RH. On the thermal sensation of the legs, at the lower humidity level, the elderly group felt cooler than the young group. On the dry sensation of the eyes and throat, the young group felt drier than the elderly group at the lower humidity levels. From the above results, the elderly group had difficulty in feeling dryness in the nasal mucous membrane despite being easily affected by low humidity. On the other hand, the young group felt the change of humidity sensitively despite not being severely affected by low humidity. Ocular mucosa and

  15. Morphological and Relative Humidity Sensing Properties of Pure ZnO Nanomaterial

    Directory of Open Access Journals (Sweden)

    N. K. Pandey

    2010-11-01

    Full Text Available In this paper we report the resistive type humidity sensing properties of pure ZnO nanomaterial prepared by solid-state reaction method. Pellets of pure ZnO nanocrystalline powder have been made with 10 weight % of glass powder at pressure of 260 MPa by hydraulic press machine for 3 hours. These pellets have been sintered at temperatures 200 °C - 500 °C in an electric muffle furnace for 3 hours at heating rate of 5°C/min. After sintering, these pellets have been exposed to humidity in a specially designed humidity chamber at room temperature. It has been observed that as relative humidity increases, resistance of the pellets decreases for entire range of humidity i.e. 10 % to 90 %. The sensing element of ZnO shows best results with sensitivity of 11.13 MΩ/%RH for the annealing temperature of 400 °C. This sensing element manifests lower hysteresis, less effect of aging and high reproducibility for annealing temperature 400 °C. SEM micrographs show that the sensing elements manifest porous structure with a network of pores that are expected to provide sites for humidity adsorption. The average grain size calculated from SEM micrograph is 236 nm. XRD pattern shows peaks of hexagonal zincite. As calculated from Scherer’s formula, the average crystalline size for this sensing element is 59.4 nm. For this sensing element, the values of activation energy from the Arrhenius plot is 0.041 eV for temperature range 200 °C - 400 °C and 0.393 eV for temperature range 400 °C - 500 °C. The adsorption of water molecules on the surface takes place via a dissociative chemisorption process leading to release of electrons. ZnO has electron vacancy. Hence, because of this reaction, the electrons are accumulated at the ZnO surface and consequently, the resistance of the sensing element decreases with increase in relative humidity.

  16. Turbulent transport across an interface between dry and humid air in a stratified environment

    Science.gov (United States)

    Gallana, Luca; de Santi, Francesca; di Savino, Silvio; Iovieno, Michele; Ricchiardone, Renzo; Tordella, Daniela

    2014-11-01

    The transport of energy and water vapor across a thin layer which separates two decaying isotropic turbulent flows with different kinetic energy and humidity is considered. The interface is placed in a shearless stratified environment in temporal decay. This system reproduces a few aspects of small scale turbulent transport across a dry air/moist air interface in an atmospheric like context. In our incompressible DNS at Reλ = 250 , Boussinesq's approximation is used for momentum and energy transport while the vapor is modeled as a passive scalar (Kumar, Schumacher & Shaw 2014). We investigated different stratification levels with an initial Fr between 0.8 and 8 in presence of a kinetic energy ratio equal to 7. As the buoyancy term becomes of the same order of the inertial ones, a spatial redistribution of kinetic energy, dissipation and vapor concentration is observed. This eventually leads to the onset of a well of kinetic energy in the low energy side of the mixing layer which blocks the entrainment of dry air. Results are discussed and compared with laboratory and numerical experiments. A posteriori estimates of the eventual compression/expansion of fluid particles inside the interfacial mixing layer are given (Nance & Durran 1994).

  17. Performance monitoring of an improved disposal trench in a humid environment in a fractured geology

    International Nuclear Information System (INIS)

    Mills, D.; Razor, J.

    1988-01-01

    An engineering evaluation of an improved disposal trench at the Maxey Flats Waste Disposal Site is being conducted in order to demonstrate the feasibility of a burial trench suitable for use at a site in a humid environment and underlain by complex and fractured geologic media. This demonstration is one of several proposed final site stabilization alternatives which will have to be evaluated prior to final site closure. Due to requirements in the Central Midwest Compact Commission, no waste generated as a result of the site closure may be disposed in the Commission's disposal site. Hence, the waste will be disposed on-site. The demonstration trench was constructed and filled with waste during the fall of 1985 with final trench capping being completed in July 1986. Since that time the trench has been evaluated utilizing trench settlement monument elevations, leachate production measurements, leachate radionuclide analysis, chemical tracer analysis and trench water balance. Measurements performed to date indicated that the trench lower infiltration barrier has a permeability of about 1E-7 cm/sec. Water balance measurements indicated that less than one percent of the total rainfall crossed the trench capillary barrier. No settlement of the trench cap has been observed. No liquid has appeared in the leachate collection and monitoring sumps

  18. Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo Milton Moraes

    2013-03-01

    Full Text Available Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil. Carabidae is composed mainly by ground-dwelling predator beetles. It is the fourth most diverse group within Coleoptera, but its diversity in the Neotropical region is understudied. Here we describe and analyze the diversity of carabid beetles in a region of subtropical rain forest dominated by Araucaria angustifolia with different landscapes. Three areas were chosen in an environmental integrity gradient: primary forests, secondary forests and old Pinus plantations. Pitfall traps were taken monthly, in a total of 14 samples per area. 1733 adult carabid beetles, belonging to 18 species, were sampled. There were differences in richness and abundance between the sampled areas. The total scores followed the same tendency: primary forests (14 species/747 individuals, secondary forests (13/631 and Pinus forests (10/355. An analysis of similarity shows differences in species composition, for both areas and seasons. Galerita lacordarei was the most abundant species for all samples and seasons. Carabid species show similar responses in accordance with habitat heterogeneity and disturbance. The abundance of Galerita lacordarei was influenced by temperature, for all sampled sites. Environmental changes affect the carabid assemblages and decrease diversity, possibly interfering in local dynamics. Seasonality patterns seem to indicate an increase in individual movement during summer, probably in search of resources. It is suggested that microhabitat patchiness is probably an important factor affecting carabid beetle diversity at small spatial scales.

  19. Effects of relative humidity, temperature, and population density on production of cuticular hydrocarbons in housefly Musca domestica L.

    NARCIS (Netherlands)

    Noorman, N; Den Otter, CJ

    The production of cuticular hydrocarbons by both males and females of Musca domestica L. under very wet conditions (90% relative humidity) compared to the production at 50 and 20% relative humidity is delayed up to at least 3 days after emergence from the pupae. Eight days after emergence, however,

  20. Quantitative Ethylene Measurements with MOx Chemiresistive Sensors at Different Relative Air Humidities

    Directory of Open Access Journals (Sweden)

    Matic Krivec

    2015-11-01

    Full Text Available The sensitivity of two commercial metal oxide (MOx sensors to ethylene is tested at different relative humidities. One sensor (MiCS-5914 is based on tungsten oxide, the other (MQ-3 on tin oxide. Both sensors were found to be sensitive to ethylene concentrations down to 10 ppm. Both sensors have significant response times; however, the tungsten sensor is the faster one. Sensor models are developed that predict the concentration of ethylene given the sensor output and the relative humidity. The MQ-3 sensor model achieves an accuracy of ±9.2 ppm and the MiCS-5914 sensor model predicts concentration to ±7.0 ppm. Both sensors are more accurate for concentrations below 50 ppm, achieving ±6.7 ppm (MQ-3 and 5.7 ppm (MiCS-5914.

  1. Inter-Laboratory Comparison for Calibration of Relative Humidity Devices Among Accredited Laboratories in Malaysia

    Science.gov (United States)

    Hussain, F.; Khairuddin, S.; Othman, H.

    2017-01-01

    An inter-laboratory comparison in relative humidity measurements among accredited laboratories has been coordinated by the National Metrology Institute of Malaysia. It was carried out to determine the performance of the participating laboratories. The objective of the comparison was to acknowledge the participating laboratories competencies and to verify the level of accuracies declared in their scope of accreditation, in accordance with the MS ISO/IEC 17025 accreditation. The measurement parameter involved was relative humidity for the range of 30-90 %rh at a nominal temperature of 50°C. Eight accredited laboratories participated in the inter-laboratory comparison. Two units of artifacts have been circulated among the participants as the transfer standards.

  2. Population growth and development of Liposcelis pearmani (Psocoptera: Liposcelididae) at constant temperatures and relative humidities.

    Science.gov (United States)

    Aminatou, B A; Gautam, S G; Opit, G P; Talley, J; Shakya, K

    2011-08-01

    Psocids of genus Liposcelis are now considered serious pests of stored products. We investigated the effects of eight temperatures (22.5, 25.0, 27.5, 30.0, 32.5, 35.0, 37.5, and 40.0°C) and four relative humidities (43, 55, 63, and 75%) on population growth and development of the psocid Liposcelis pearmani Lienhard. L. pearmani did not survive at 37.5 and 40.0°C, at all relative humidities tested; at 43% RH, at all temperatures tested; and at 55% RH, at 32.5 and 35°C. The greatest population growth was recorded at 32.5°C and 75% RH (32-fold growth). L. pearmani males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 17, 63, and 20%, respectively. Female L. pearmani have two to five instars, and the percentages of females with two, three, four, and five instars were 5, 39, 55, and 1%, respectively. We developed temperature-dependent development equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages. Based on 30-d population growth, L. pearmani cannot survive at temperatures >35.0°C; does not thrive at low relative humidities (55%), at temperatures above 25°C; and has a high optimum relative humidity for population growth (75%). Therefore, we expect it to have a more limited distribution compared with other Liposcelis species. These data provide a better understanding of how temperature and RH may influence L. pearmani population dynamics and can be used in population growth models to help develop effective management strategies for this psocid, and to predict its occurrence.

  3. Creep behavior of sweetgum OSB: effect of load level and relative humidity

    Science.gov (United States)

    J.H. Pu; R.C. Tang; Chung-Yun Hse

    1994-01-01

    Flexural creep behavior of laboratory-fabricated sweetgum oriented strandboard (OSB). under constnat (65% and 95%) and cyclic (65% 95% at a 96-hr. frequency) relative humidity (RH) conditions at 75 F (23.9 C) is presented. Two levels (4.5% and 6.5%) of resin content (RC) of phenol-formaldehyde were used in fabricating the test panels. Two load levels (20% and...

  4. Statistical Modelling of Temperature and Moisture Uptake of Biochars Exposed to Selected Relative Humidity of Air

    Directory of Open Access Journals (Sweden)

    Luciane Bastistella

    2018-02-01

    Full Text Available New experimental techniques, as well as modern variants on known methods, have recently been employed to investigate the fundamental reactions underlying the oxidation of biochar. The purpose of this paper was to experimentally and statistically study how the relative humidity of air, mass, and particle size of four biochars influenced the adsorption of water and the increase in temperature. A random factorial design was employed using the intuitive statistical software Xlstat. A simple linear regression model and an analysis of variance with a pairwise comparison were performed. The experimental study was carried out on the wood of Quercus pubescens, Cyclobalanopsis glauca, Trigonostemon huangmosun, and Bambusa vulgaris, and involved five relative humidity conditions (22, 43, 75, 84, and 90%, two mass samples (0.1 and 1 g, and two particle sizes (powder and piece. Two response variables including water adsorption and temperature increase were analyzed and discussed. The temperature did not increase linearly with the adsorption of water. Temperature was modeled by nine explanatory variables, while water adsorption was modeled by eight. Five variables, including factors and their interactions, were found to be common to the two models. Sample mass and relative humidity influenced the two qualitative variables, while particle size and biochar type only influenced the temperature.

  5. Effect of Relative Humidity on Adsorption Breakthrough of CO2 on Activated Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Yu-Chun Chiang

    2017-11-01

    Full Text Available Microporous activated carbon fibers (ACFs were developed for CO2 capture based on potassium hydroxide (KOH activation and tetraethylenepentamine (TEPA amination. The material properties of the modified ACFs were characterized using several techniques. The adsorption breakthrough curves of CO2 were measured and the effect of relative humidity in the carrier gas was determined. The KOH activation at high temperature generated additional pore networks and the intercalation of metallic K into the carbon matrix, leading to the production of mesopore and micropore volumes and providing access to the active sites in the micropores. However, this treatment also resulted in the loss of nitrogen functionalities. The TEPA amination has successfully introduced nitrogen functionalities onto the fiber surface, but its long-chain structure blocked parts of the micropores and, thus, made the available surface area and pore volume limited. Introduction of the power of time into the Wheeler equation was required to fit the data well. The relative humidity within the studied range had almost no effects on the breakthrough curves. It was expected that the concentration of CO2 was high enough so that the impact on CO2 adsorption capacity lessened due to increased relative humidity.

  6. Air temperature and relative humidity in Dome Fuji Station buildings, East Antarctic ice sheet, in 2003

    Directory of Open Access Journals (Sweden)

    Takao Kameda

    2008-06-01

    Full Text Available In order to clarify the living condition in Dome Fuji Station in 2003, air temperature and relative humidity in the station were measured. Thermocouples with data logger and a ventilated psychrometer were used for the measurements. Average air temperature from February 11, 2003 to January 14, 2004 (missing period: July 19 to August 17 in the Dome Fuji Station buildings were as follows: Generator room 24.7℃, Dining room 23.5℃, Observation room 21.1℃, Dormitory room 18.2℃, Corridor 18.2℃, Food storage 8.2℃ and Old ice coring site -51.3℃. Average outside air temperature (1.5m height from the snow surface during the period was -54.4℃. A remarkable increase of outside air temperature (+30℃ at maximum due to a blocking high event was observed from October 31, 2003 to November 10, 2003 at Dome Fuji, during which increase of air temperature from 5 to 8°C in the station buildings was recorded. Snow on the station buildings was partly melted and some of the melted water penetrated into the station. This was the only time snow melted during the wintering over party's stay at the station. Average relative humidity in the station buildings obtained using a small humidifier was about 25%; the relative humidity without using the humidifier ranged from 9.0 to 22.9%.

  7. Efficiency of producing anion and relative humidity of the indigenous woody plants in Jeju islands

    Science.gov (United States)

    Son, S.-G.; Kim, K.-J.; Kim, H.-J.; Kim, C.-M.; Byun, K.-O.

    2009-04-01

    This study is to evaluate the ability of interior plants to produce anion and relative humidity that can purify polluted indoor air. Four indigenous woody plants in Jeju islands such as Sarcandra glaber (Thunb.) Nakai, Illicium anisatum L, Cleyera japonica Thunb. and Ilex rotunda Thunb. were used. Sansevieria trifasciata cv. Laurentii was also used as a comparative plant. The amount of anion and increment of relative humidity produced by five species of indoor plants was assessed by anion measurement (ITC-201A)in a sealed acryl chamber (118Ã-118Ã-119.5cm). The highest amount of anion was 515 ea/cm3produced by I. rotunda. The amounts of anion were 293 ea/cm3, 273 ea/cm3, and 211 ea/cm3 in S. glaber, I. anisatum and C. japonica, respecively while it was 220 ea/cm3 in S. trifasciata. The increment of relative humidity was highest in I. anisatum as 27.4% while it was lowest in S. trifasciata as 14.0%. This result suggested that all four indigenous plants tested were more effective to purify the indoor polluted air than S. trifasciata. Key words: interior plant, S. glaber, I. anisatum, C. japonica, I. rotunda, indoor polluted air

  8. Nacre-like hybrid films: Structure, properties, and the effect of relative humidity.

    Science.gov (United States)

    Abba, Mohammed T; Hunger, Philipp M; Kalidindi, Surya R; Wegst, Ulrike G K

    2015-03-01

    Functional materials often are hybrids composed of biopolymers and mineral constituents. The arrangement and interactions of the constituents frequently lead to hierarchical structures with exceptional mechanical properties and multifunctionality. In this study, hybrid thin films with a nacre-like brick-and-mortar microstructure were fabricated in a straightforward and reproducible manner through manual shear casting using the biopolymer chitosan as the matrix material (mortar) and alumina platelets as the reinforcing particles (bricks). The ratio of inorganic to organic content was varied from 0% to 15% and the relative humidities from 36% to 75% to determine their effects on the mechanical properties. It was found that increasing the volume fraction of alumina from 0% to 15% results in a twofold increase in the modulus of the film, but decreases the tensile strength by up to 30%, when the volume fraction of alumina is higher than 5%. Additionally, this study quantifies and illustrates the critical role of the relative humidity on the mechanical properties of the hybrid film. Increasing the relative humidity from 36% to 75% decreases the modulus and strength by about 45% and triples the strain at failure. These results suggest that complex hybrid materials can be manufactured and tailor made for specific applications or environmental conditions. Copyright © 2015. Published by Elsevier Ltd.

  9. Bond Strength of Resin Composite to Dentin with Different Adhesive Systems: Influence of Relative Humidity and Application Time.

    Science.gov (United States)

    Amsler, Fabienne; Peutzfeldt, Anne; Lussi, Adrian; Flury, Simon

    2015-06-01

    To investigate the influence of relative humidity and application time on bond strength to dentin of different classes of adhesive systems. A total of 360 extracted human molars were ground to mid-coronal dentin. The dentin specimens were treated with one of six adhesive systems (Syntac Classic, OptiBond FL, Clearfil SE Bond, AdheSE, Xeno Select, or Scotchbond Universal), and resin composite (Filtek Z250) was applied to the treated dentin surface under four experimental conditions (45% relative humidity/application time according to manufacturers' instructions; 45% relative humidity/reduced application time; 85% relative humidity/application time according to manufacturers' instructions; 85% relative humidity/reduced application time). After storage (37°C, 100% humidity, 24 h), shear bond strength (SBS) was measured and data analyzed with nonparametric ANOVA followed by Kruskal-Wallis tests and Mann-Whitney U-tests with Bonferroni-Holm correction for multiple testing (level of significance: α = 0.05). Increased relative humidity and reduced application time had no effect on SBS for Clearfil SE Bond and Scotchbond Universal (p = 1.00). For Syntac Classic, OptiBond FL, AdheSE, and Xeno Select there was no effect on SBS of reduced application time of the adhesive system (p ≥ 0.403). However, increased relative humidity significantly reduced SBS for Syntac Classic, OptiBond FL, and Xeno Select irrespective of application time (p ≤ 0.003), whereas for AdheSE, increased relative humidity significantly reduced SBS at recommended application time only (p = 0.002). Generally, increased relative humidity had a detrimental effect on SBS to dentin, but reduced application time had no effect.

  10. Ozone decomposition kinetics on alumina: effects of ozone partial pressure, relative humidity and repeated oxidation cycles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2004-01-01

    Full Text Available The room temperature kinetics of gas-phase ozone loss via heterogeneous interactions with thin alumina films has been studied in real-time using 254nm absorption spectroscopy to monitor ozone concentrations. The films were prepared from dispersions of fine alumina powder in methanol and their surface areas were determined by an in situ procedure using adsorption of krypton at 77K. The alumina was found to lose reactivity with increasing ozone exposure. However, some of the lost reactivity could be recovered over timescales of days in an environment free of water, ozone and carbon dioxide. From multiple exposures of ozone to the same film, it was found that the number of active sites is large, greater than 1.4x1014 active sites per cm2 of surface area or comparable to the total number of surface sites. The films maintain some reactivity at this point, which is consistent with there being some degree of active site regeneration during the experiment and with ozone loss being catalytic to some degree. The initial uptake coefficients on fresh films were found to be inversely dependent on the ozone concentration, varying from roughly 10-6 for ozone concentrations of 1014 molecules/cm3 to 10-5 at 1013 molecules/cm3. The initial uptake coefficients were not dependent on the relative humidity, up to 75%, within the precision of the experiment. The reaction mechanism is discussed, as well as the implications these results have for assessing the effect of mineral dust on atmospheric oxidant levels.

  11. INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON THE STUDDED AGARICUS BLAZEI MURRILL MUSHROOM COMPOST

    Directory of Open Access Journals (Sweden)

    Sándor Rózsa

    2017-12-01

    Full Text Available Almond mushroom, Agaricus blazei Murrill, is the so-called secondary saprophyte, developing on partially processed substrate, in which microorganisms reduced complex ligno-cellulose compounds. Numerous authors have shown that due to the similar life cycle in the cultivation of almond mushroom technologies developed for white button mushroom may be applied. However, almond mushroom requires high temperature and high humidity as well as access to light to form fruiting bodies. In Brazil, due to the advantageous climatic conditions this species is frequently grown outdoors; however, in other countries - mainly due to its high temperature requirements - such cultivation system is risky and may only be successful during very warm summers. In this study, we analyzed four kind of compost studded by Agaricus blazei Murrill mushroom mycelium. We recorded every hour the air and compost temperature and the air relative humidity. The best studded compost was the classical, followed by synthetic and then by the mixt compost.

  12. High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes.

    Science.gov (United States)

    Devleesschauwer, Brecht; Marvasi, Massimiliano; Giurcanu, Mihai C; Hochmuth, George J; Speybroeck, Niko; Havelaar, Arie H; Teplitski, Max

    2017-09-01

    Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

    Science.gov (United States)

    Chen, Rong; Sung, Wen-Pei; Chang, Hung-Chang; Chi, Yi-Rou

    2013-01-01

    A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1) measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2) implementing questionnaire survey analysis to explore people's environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3) constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV), two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C) indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1 ~ 0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement. PMID:24311976

  14. Applying Outdoor Environment to Develop Health, Comfort, and Energy Saving in the Office in Hot-Humid Climate

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

    Full Text Available A human life demand set to emerge in the future is the achievement of sustainability by maintaining a comfortable indoor environment without excessive reliance on energy-consuming air conditioners. The major research processes in this study are: (1 measuring indoor air quality and thermal comfort to evaluate the comfort of an indoor environment; (2 implementing questionnaire survey analysis to explore people’s environmental self-perceptions and conducting a meta-analysis of the measurement results for air quality and physical aspects; and (3 constructing an indoor monitoring and management system. The experimental and analysis results of this research reveal that most of the office occupants preferred a cooler environment with a lower temperature. Additionally, because the summers in Taiwan are humid and hot, the occupants of an indoor space tend to feel uncomfortable because of the high humidity and poor indoor air quality. Therefore, Variable Air Volume (VAV, two air intakes, and exhaust plant are installed to improve indoor environment. After improvement, a lower temperature (approximately 21.2–23.9°C indirectly reduces humidity, thereby making the occupants comfortable. Increasing air velocity to 0.1~0.15 m/s, the carbon dioxide concentrations decrease below the requirement of the WHO. Ninety-five percent of the workers corresponded to the standard comfort zone after this improvement.

  15. Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions

    Science.gov (United States)

    Gerba, Charles P.; Tamimi, Akrum H.; Kitajima, Masaaki; Maxwell, Sheri L.; Rose, Joan B.

    2013-01-01

    Fomites can serve as routes of transmission for both enteric and respiratory pathogens. The present study examined the effect of low and high relative humidity on fomite-to-finger transfer efficiency of five model organisms from several common inanimate surfaces (fomites). Nine fomites representing porous and nonporous surfaces of different compositions were studied. Escherichia coli, Staphylococcus aureus, Bacillus thuringiensis, MS2 coliphage, and poliovirus 1 were placed on fomites in 10-μl drops and allowed to dry for 30 min under low (15% to 32%) or high (40% to 65%) relative humidity. Fomite-to-finger transfers were performed using 1.0 kg/cm2 of pressure for 10 s. Transfer efficiencies were greater under high relative humidity for both porous and nonporous surfaces. Most organisms on average had greater transfer efficiencies under high relative humidity than under low relative humidity. Nonporous surfaces had a greater transfer efficiency (up to 57%) than porous surfaces (humidity, as well as under high relative humidity (nonporous, up to 79.5%; porous, <13.4%). Transfer efficiency also varied with fomite material and organism type. The data generated can be used in quantitative microbial risk assessment models to assess the risk of infection from fomite-transmitted human pathogens and the relative levels of exposure to different types of fomites and microorganisms. PMID:23851098

  16. Life table parameters of three Mirid Bug (Adelphocoris species (Hemiptera: Miridae under contrasted relative humidity regimes.

    Directory of Open Access Journals (Sweden)

    Hongsheng Pan

    Full Text Available The genus Adelphocoris (Hemiptera: Miridae is a group of important insect pests of Bt cotton in China. The three dominant species are A. lineolatus, A. suturalis, and A. fasciaticollis, and these species have different population dynamics. The causal factors for the differences in population dynamics have not been determined; one hypothesis is that humidity may be important for the growth of Adelphocoris populations. In the laboratory, the demographic parameters of the three Adelphocoris species were compared when the mirid bugs were subjected to various levels of relative humidity (40, 50, 60, 70 and 80% RH. Middle to high levels of RH (60, 70 and 80% were associated with higher egg and nymph survival rates and increased adult longevity and female fecundity. Lower humidity levels (40 and 50% RH had negative effects on the survival of nymphs, adult longevity and fecundity. The intrinsic rate of increase (rm, the net reproductive rate (R0 and the finite rate of increase (λ for each Adelphocoris species increased with increasing RH. Significant positive relationships were found between RH and the life table parameters, rm, R0 and λ for the three Adelphocoris species. These results will help to better understand the phenology of the three Adelphocoris species, and the information can be used in population growth models to optimize pest forecasting and management strategies for these key pests.

  17. High resolution dynamical downscaling of air temperature and relative humidity: performance assessment of WRF for Portugal

    Science.gov (United States)

    Menezes, Isilda; Pereira, Mário; Moreira, Demerval; Carvalheiro, Luís; Bugalho, Lourdes; Corte-Real, João

    2017-04-01

    Air temperature and relative humidity are two of the atmospheric variables with higher impact on human and natural systems, contributing to define the stress/comfortable conditions, affecting the productivity and health of the individuals as well as diminishing the resilience to other environmental hazards. Atmospheric regional models, driven by large scale forecasts from global circulation models, are the best way to reproduce such environmental conditions in high space-time resolution. This study is focused on the performance assessment of the WRF mesoscale model to perform high resolution dynamical downscaling for Portugal with three two-way nested grids, at 60 km, 20 km and 5 km horizontal resolution. The simulations of WRF models were produced with different initial and boundary forcing conditions. The NCEP-FNL Operational Global Analysis data available on 1-degree by 1-degree grid every six hours and ERA-Interim reanalyses dataset were used to drive the models. Two alternative configurations of the WRF model, including planetary boundary, layer schemes, microphysics, land-surface models, radiation schemes, were used and tested within the 5 km spatial resolution domain. Simulations of air temperature and relative humidity were produced for January and July of 2016 and compared with the observed datasets provided by the Instituto Português do Mar e da Atmosfera (IPMA) for 83 weather stations. Different performance measures of bias, precision, and accuracy were used, namely normalized bias, standard deviation, mean absolute error, root mean square error, bias of root mean square error as well as correlation based measures (e.g., coefficient of determination) and goodness of fit measures (index of agreement). Main conclusions from the obtained results reveal: (i) great similarity between the spatial patterns of the simulated and observed fields; (ii) only small differences between simulations produced with ERA-Interim and NCEP-FNL, in spite of some differences

  18. Water sorption in wood and modified wood at high values of relative humidity

    DEFF Research Database (Denmark)

    Engelund, Emil Tang; Thygesen, Lisbeth Garbrecht; Hoffmeyer, Preben

    2010-01-01

    A theoretical study of the amount of moisture held in wood as capillary condensed water in the relative humidity (RH) range of 90–99.9% is carried out. The study is based on idealized geometries of the softwood structure related to micrographs. It is confined to structural elements such as bordered......, and different degrees of pit aspiration are assigned to earlywood and latewood. We suggest based on the results that capillary condensation makes only a very small contribution to the equilibrium moisture content. At 99.9% RH the contribution amounts to less than 0.0035 kg water per kg dry wood. This is in line...

  19. Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modelling

    Directory of Open Access Journals (Sweden)

    M. Brabec

    2012-10-01

    Full Text Available Advanced measurement and modelling techniques are employed to estimate the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and out-of-cloud supersaturations with respect to ice. In November 2008 the newly developed balloon-borne backscatter sonde COBALD (Compact Optical Backscatter and AerosoL Detector was flown 14 times together with a CFH (Cryogenic Frost point Hygrometer from Lindenberg, Germany (52° N, 14° E. The case discussed here in detail shows two cirrus layers with in-cloud relative humidities with respect to ice between 50% and 130%. Global operational analysis data of ECMWF (roughly 1° × 1° horizontal and 1 km vertical resolution, 6-hourly stored fields fail to represent ice water contents and relative humidities. Conversely, regional COSMO-7 forecasts (6.6 km × 6.6 km, 5-min stored fields capture the measured humidities and cloud positions remarkably well. The main difference between ECMWF and COSMO data is the resolution of small-scale vertical features responsible for cirrus formation. Nevertheless, ice water contents in COSMO-7 are still off by factors 2–10, likely reflecting limitations in COSMO's ice phase bulk scheme. Significant improvements can be achieved by comprehensive size-resolved microphysical and optical modelling along backward trajectories based on COSMO-7 wind and temperature fields, which allow accurate computation of humidities, homogeneous ice nucleation, resulting ice particle size distributions and backscatter ratios at the COBALD wavelengths. However, only by superimposing small-scale temperature fluctuations, which remain unresolved by the numerical weather prediction models, can we obtain a satisfying agreement with the observations and reconcile the measured in-cloud non-equilibrium humidities with conventional ice cloud microphysics. Conversely, the model-data comparison provides no evidence that additional

  20. Conception through build of an automated liquids processing system for compound management in a low-humidity environment.

    Science.gov (United States)

    Belval, Richard; Alamir, Ab; Corte, Christopher; DiValentino, Justin; Fernandes, James; Frerking, Stuart; Jenkins, Derek; Rogers, George; Sanville-Ross, Mary; Sledziona, Cindy; Taylor, Paul

    2012-12-01

    Boehringer Ingelheim's Automated Liquids Processing System (ALPS) in Ridgefield, Connecticut, was built to accommodate all compound solution-based operations following dissolution in neat DMSO. Process analysis resulted in the design of two nearly identical conveyor-based subsystems, each capable of executing 1400 × 384-well plate or punch tube replicates per batch. Two parallel-positioned subsystems are capable of independent execution or alternatively executed as a unified system for more complex or higher throughput processes. Primary ALPS functions include creation of high-throughput screening plates, concentration-response plates, and reformatted master stock plates (e.g., 384-well plates from 96-well plates). Integrated operations included centrifugation, unsealing/piercing, broadcast diluent addition, barcode print/application, compound transfer/mix via disposable pipette tips, and plate sealing. ALPS key features included instrument pooling for increased capacity or fail-over situations, programming constructs to associate one source plate to an array of replicate plates, and stacked collation of completed plates. Due to the hygroscopic nature of DMSO, ALPS was designed to operate within a 10% relativity humidity environment. The activities described are the collaborative efforts that contributed to the specification, build, delivery, and acceptance testing between Boehringer Ingelheim Pharmaceuticals, Inc. and the automation integration vendor, Thermo Scientific Laboratory Automation (Burlington, ON, Canada).

  1. Measurement of Temperature and Relative Humidity with Polymer Optical Fiber Sensors Based on the Induced Stress-Optic Effect

    Science.gov (United States)

    Pontes, Maria José

    2018-01-01

    This paper presents a system capable of measuring temperature and relative humidity with polymer optical fiber (POF) sensors. The sensors are based on variations of the Young’s and shear moduli of the POF with variations in temperature and relative humidity. The system comprises two POFs, each with a predefined torsion stress that resulted in a variation in the fiber refractive index due to the stress-optic effect. Because there is a correlation between stress and material properties, the variation in temperature and humidity causes a variation in the fiber’s stress, which leads to variations in the fiber refractive index. Only two photodiodes comprise the sensor interrogation, resulting in a simple and low-cost system capable of measuring humidity in the range of 5–97% and temperature in the range of 21–46 °C. The root mean squared errors (RMSEs) between the proposed sensors and the reference were 1.12 °C and 1.36% for the measurements of temperature and relative humidity, respectively. In addition, fiber etching resulted in a sensor with a 2 s response time for a relative humidity variation of 10%, which is one of the lowest recorded response times for intrinsic POF humidity sensors. PMID:29558387

  2. Measurements of Humidity and Temperature in the Marine Environment during the HEXOS Main Experiment

    NARCIS (Netherlands)

    Katsaros, K.B.; Cosmo, J. de; Lind, R.J.; Anderson, R.J.; Smith, S.D.; Kraan, R.; Oost, W.A.; Uhlig, K.; Mestayer, P.G.; Larsen, S.E.; Smith, M.H.; Leeuw, G. de

    1994-01-01

    Accurate measurement of fluctuations in temperature and humidity are needed for determination of the surface evaporation rate and the air-sea sensible heat flux using either the eddy correlation or inertial dissipation method for flux calculations. These measurements are difficult to make over the

  3. Seasonal variations of indoor microbial exposures and their relation to temperature, relative humidity, and air exchange rate.

    Science.gov (United States)

    Frankel, Mika; Bekö, Gabriel; Timm, Michael; Gustavsen, Sine; Hansen, Erik Wind; Madsen, Anne Mette

    2012-12-01

    Indoor microbial exposure has been related to adverse pulmonary health effects. Exposure assessment is not standardized, and various factors may affect the measured exposure. The aim of this study was to investigate the seasonal variation of selected microbial exposures and their associations with temperature, relative humidity, and air exchange rates in Danish homes. Airborne inhalable dust was sampled in five Danish homes throughout the four seasons of 1 year (indoors, n = 127; outdoors, n = 37). Measurements included culturable fungi and bacteria, endotoxin, N-acetyl-beta-d-glucosaminidase, total inflammatory potential, particles (0.75 to 15 μm), temperature, relative humidity, and air exchange rates. Significant seasonal variation was found for all indoor microbial exposures, excluding endotoxin. Indoor fungi peaked in summer (median, 235 CFU/m(3)) and were lowest in winter (median, 26 CFU/m(3)). Indoor bacteria peaked in spring (median, 2,165 CFU/m(3)) and were lowest in summer (median, 240 CFU/m(3)). Concentrations of fungi were predominately higher outdoors than indoors, whereas bacteria, endotoxin, and inhalable dust concentrations were highest indoors. Bacteria and endotoxin correlated with the mass of inhalable dust and number of particles. Temperature and air exchange rates were positively associated with fungi and N-acetyl-beta-d-glucosaminidase and negatively with bacteria and the total inflammatory potential. Although temperature, relative humidity, and air exchange rates were significantly associated with several indoor microbial exposures, they could not fully explain the observed seasonal variations when tested in a mixed statistical model. In conclusion, the season significantly affects indoor microbial exposures, which are influenced by temperature, relative humidity, and air exchange rates.

  4. Dependence of alpha radionuclide diffusion and deposition on relative air humidity

    International Nuclear Information System (INIS)

    Danis, A.; Ciubotariu, M.; Oncescu, M.; Mocsy, I.; Tomulescu, V.

    2000-01-01

    The diffusion and deposition of the gaseous and solid alpha radionuclides/aerosols depend strongly on the relative air humidity. This dependence gets a great significance in the case of radon and their genetically related alpha radionuclides monitoring in the dwelling and working places for radioprotection purposes, particularly in establishing the equilibrium factor. For the gaseous and solid alpha radionuclides genetically related, Rn-222 and its solid alpha descendants including their aerosols obtained by radionuclide attachments to different particles present in air, the vertical gradient of volume concentrations was experimentally determined. The experiments were performed in: an airtight tubular laboratory chamber, a house cellar (Cluj-Napoca) and the entrance gallery of an abandoned mine (Avram Iancu, Bihor), in which the relative humidity was ranging from 65% up to 96%. For the laboratory chamber, these radionuclides were generated by a calibrated Ra-226 source, prepared at the Radionuclide Production Centre, IPNE-HH, Bucharest. The source was included into an air tight device with a well known volume and it was used only after 40 days, when the Ra-226 and its alpha descendants were under radioactive equilibrium. For the diffusion/deposition studies, this source was coupled with the airtight laboratory chamber. In the mine gallery and house cellar, the radon and its descendants were naturally and continuously generated by radium sources in soil and building materials. The alpha volume concentration determinations required the use of a very accurate and sensitive alpha measurement method. These requirements were met by the alpha track method. This method was used by us in the following conditions: the CR-39 plastic track detector (Page, England) for the detection of the alpha particles and the optical microscopy for the study of alpha tracks (Wild stereomicroscope M7S and a Karl Zeiss Jena binocular microscope). The volume concentrations of radon and the

  5. Vacuum FTIR Observation on the Dynamic Hygroscopicity of Aerosols under Pulsed Relative Humidity.

    Science.gov (United States)

    Leng, Chun-Bo; Pang, Shu-Feng; Zhang, Yun; Cai, Chen; Liu, Yong; Zhang, Yun-Hong

    2015-08-04

    A novel approach based on a combination of a pulse RH controlling system and a rapid scan vacuum FTIR spectrometer (PRHCS-RSVFTIR) was utilized to investigate dynamic hygroscopicity of two atmospheric aerosols: ammonium sulfate ((NH4)2SO4) and magnesium sulfate (MgSO4). In this approach, rapid-scan infrared spectra of water vapor and aerosols were obtained to determine relative humidity (RH) in sample cell and hygroscopic property of aerosols with a subsecond time resolution. Heterogeneous nucleation rates of (NH4)2SO4 were, for the first time, measured under low RH conditions (nucleation kinetics of liquid aerosols.

  6. The effect of temperature and relative humidity on survival of unfed hyalomma impeltatum (acarina: ixodidae)

    OpenAIRE

    Hagras, Ahmed E. E. [احمد الوزير هجرس; Babiker, A. A.; Khalil, G. M.

    1991-01-01

    This work investigates survival of unfed Hyalomma impeltatum in which 8089 larvae, 3946 nymphs, 2058 males and 2304 females held at different combinations of temperature (21, 25, 29 and 34°C) and relative humidity (RH) (32, 52, 75 and 97%) levels. Survival was significantly improved with rise in RH and fall in temperature in all stages. The magnitude of the effect of RH and temperature on survival varied significantly between stages. Changes in RH and temperature had a stronger impact on surv...

  7. Determination of partition and diffusion coefficients of formaldehyde in selected building materials and impact of relative humidity (journal)

    Science.gov (United States)

    The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

  8. Determination of partition and diffusion coefficient of formaldehyde in selected building materials and impact of relative humidity

    Science.gov (United States)

    The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test meth...

  9. Influence of relative humidity and temperature on quantity of electric charge of static protective clothing used in petrochemical industry

    International Nuclear Information System (INIS)

    Zhang, Yunpeng; Liu, Quanzhen; Liu, Baoquan; Li, Yipeng; Zhang, Tingting

    2013-01-01

    In this paper, the working principle of static protective clothing and its testing method of quantity of electric charge are introduced, and the influence of temperature and relative humidity on the quantity of electric charge (q e ) of static protective clothing is studied by measuring q e of different clothing samples. The result shows that temperature and relative humidity can influence q e of static protective clothing to some extent and the influence of relative humidity is bigger than that of temperature. According to experimental results, the relationship of q e and relative humidity and temperature was analysed, and the safety boundary of quantity of electric charge is discussed. In order to reduce the occurrence of electrostatic accidents and ensure safe production and operation of petrochemical industry, some suggestions on choosing and using of static protective clothing are given for guaranteeing its static protective performance.

  10. Influence of relative humidity and temperature on quantity of electric charge of static protective clothing used in petrochemical industry

    Science.gov (United States)

    Zhang, Yunpeng; Liu, Quanzhen; Liu, Baoquan; Li, Yipeng; Zhang, Tingting

    2013-03-01

    In this paper, the working principle of static protective clothing and its testing method of quantity of electric charge are introduced, and the influence of temperature and relative humidity on the quantity of electric charge (qe) of static protective clothing is studied by measuring qe of different clothing samples. The result shows that temperature and relative humidity can influence qe of static protective clothing to some extent and the influence of relative humidity is bigger than that of temperature. According to experimental results, the relationship of qe and relative humidity and temperature was analysed, and the safety boundary of quantity of electric charge is discussed. In order to reduce the occurrence of electrostatic accidents and ensure safe production and operation of petrochemical industry, some suggestions on choosing and using of static protective clothing are given for guaranteeing its static protective performance.

  11. Influences of thickness, scanning velocity and relative humidity on the frictional properties of WS2 nanosheets

    Science.gov (United States)

    Feng, Dongdong; Peng, Jinfeng; Liu, Sisi; Zheng, Xuejun; Yan, Xinyang; He, Wenyuan

    2018-01-01

    Distinguishing with the traditional cantilever mechanics method, we propose the extended cantilever mechanics method to calibrate the lateral calibration factor by using the normal spring constant obtained from atomic force microscopy (AFM) but not the Young’s modulus and the width of the cantilever, before the influences of thickness, scanning velocity and humidity on the frictional properties are investigated via friction measurement performed by the lateral force mode (LFM) of AFM. Tungsten disulfide (WS2) nanosheets were prepared through hydrothermal intercalation and exfoliation route, and AFM and Raman microscope were used to investigate the frictional properties, thickness and crystalline structure. The friction force and coefficient decrease monotonically with the increase of the nanosheet’s thickness, and the friction coefficient minimum value is close to 0.012 when the thickness larger than 5 nm. The friction property variation on the nanosheet’s thickness can be explained by the puckering effect of tip-sheet adhesion according thickness dependence of bending stiffness in the frame of continuum mechanics. The friction force is a constant value 1.7 nN when the scanning speed larger than the critical value 3.10 μm s-1, while it logarithmically increases for the scanning speed less than the critical value. It is easy to understand through the energy dissipation model and the thermally activated effect. The friction force and friction coefficient increase with the relative humidity at the range of 30%-60%, and the latter is at the range of 0.010-0.013. Influence of relative humidity is discussed via the increasing area of the water monolayer during the water adsorption process. The research can not only enrich nanotribology theory, but also prompt two dimensions materials for nanomechanical applications.

  12. Evaporation Kinetics of Laboratory Generated Secondary Organic Aerosols at Elevated Relative Humidity

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Jacqueline M.; Imre, D.; Beranek, Josef; Shrivastava, ManishKumar B.; Zelenyuk, Alla

    2015-01-06

    Secondary organic aerosols (SOA) dominate atmospheric organic aerosols that affect climate, air quality, and health. Recent studies indicate that, contrary to previously held assumptions, at low relative humidity (RH) these particles are semi-solid and evaporate orders of magnitude slower than expected. Elevated relative humidity has the potential to affect significantly formation, properties, and atmospheric evolution of SOA particles. Here we present a study of the effect of RH on the room-temperature evaporation kinetics of SOA particles formed by ozonolysis of α-pinene and limonene. Experiments were carried out on SOA particles generated, evaporated, and aged at 0%, 50% and 90% RH. We find that in all cases evaporation begins with a relatively fast phase, during which 30% to 70% of the particle mass evaporates in 2 hours, followed by a much slower evaporation rate. Evaporation kinetics at 0% and 50% RH are nearly the same, while at 90% RH a slightly larger fraction evaporates. In all cases, aging the particles prior to inducing evaporation reduces the evaporative losses, with aging at elevated RH leading to more significant effect. In all cases, SOA evaporation is nearly size-independent, providing direct evidence that oligomers play a crucial role in determining the evaporation kinetics.

  13. EDITORIAL: Humidity sensors Humidity sensors

    Science.gov (United States)

    Regtien, Paul P. L.

    2012-01-01

    All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be

  14. Relative humidity impact on aerosol parameters in a Paris suburban area

    Directory of Open Access Journals (Sweden)

    H. Randriamiarisoa

    2006-01-01

    Full Text Available Measurements of relative humidity (RH and aerosol parameters (scattering cross section, size distributions and chemical composition, performed in ambient atmospheric conditions, have been used to study the influence of relative humidity on aerosol properties. The data were acquired in a suburban area south of Paris, between 18 and 24 July 2000, in the framework of the 'Etude et Simulation de la Qualité de l'air en Ile-de-France' (ESQUIF program. According to the origin of the air masses arriving over the Paris area, the aerosol hygroscopicity is more or less pronounced. The aerosol chemical composition data were used as input of a thermodynamic model to simulate the variation of the aerosol water mass content with ambient RH and to determine the main inorganic salt compounds. The coupling of observations and modelling reveals the presence of deliquescence processes with hysteresis phenomenon in the hygroscopic growth cycle. Based on the Hänel model, parameterisations of the scattering cross section, the modal radius of the accumulation mode of the size distribution and the aerosol water mass content, as a function of increasing RH, have been assessed. For the first time, a crosscheck of these parameterisations has been performed and shows that the hygroscopic behaviour of the accumulation mode can be coherently characterized by combined optical, size distribution and chemical measurements.

  15. Induction of Viable but Nonculturable Salmonella in Exponentially Grown Cells by Exposure to a Low-Humidity Environment and Their Resuscitation by Catalase.

    Science.gov (United States)

    Morishige, Yuta; Koike, Atsushi; Tamura-Ueyama, Ai; Amano, Fumio

    2017-02-01

    Salmonella is a major cause of foodborne disease that sometimes occurs in massive outbreaks around the world. This pathogen is tolerant of low-humidity conditions. We previously described a method for induction of viable but nonculturable (VBNC) Salmonella enterica serovar Enteritidis by treatment with hydrogen peroxide (H 2 O 2 ) and subsequent resuscitation with 0.3 mM sodium pyruvate. Here, we report a new method for the induction of the VBNC state in Salmonella Enteritidis cells, one involving dehydration. Exposure of Salmonella Enteritidis cells to dehydration stress under poor nutritional conditions (0.9% [wt/vol] NaCl) and 10 to 20% relative humidity at room temperature decreased the presence of culturable population to 0.0067%, but respiratory and glucose uptake active populations were maintained at 0.46 and 1.12%, respectively, meaning that approximately 1% may have entered the VBNC state. Furthermore, these VBNC cells could be resuscitated to acquire culturability by incubation with catalase in M9 minimal medium without glucose in a manner dependent on the dose of catalase but not sodium pyruvate. These results suggest that a low-humidity environment could cause Salmonella Enteritidis cells to enter the VBNC state and the cells could then be resuscitated for growth by treatment with catalase, suggesting a potential risk of Salmonella Enteritidis to survive in low water activity foods in the VBNC state and to start regrowth for foodborne illness.

  16. Application of graphene oxide based Microfiber-Knot resonator for relative humidity sensing

    Directory of Open Access Journals (Sweden)

    S.R. Azzuhri

    2018-06-01

    Full Text Available A relative humidity (RH sensor is proposed and demonstrated using a micro-knot resonator (MKR enhanced with a layer graphene oxide (GO coating. The MKR is fabricated by means of tapering a standard fiber, with the GO coating added by the drop-cast method. The proposed sensor is tested for an RH range of between 0% and 80% at 20% intervals, and the configurations with and without the GO coating achieve sensitivities of 0.0104 nm/% and 0.0095 nm/%, respectively. The MKR configuration without the GO coating has a linear response correlation coefficient of 0.9098 and a resolution of 0.1%, while the configuration with the GO coating has a linear response correlation coefficient of 0.9548 and a resolution of 0.096% which is better. The proposed sensor has multiple applications, especially in the area of climate and atmospheric measurement and monitoring. Keywords: Microfiber, Resonator, Humidity sensor

  17. PAIR INFLUENCE OF WIND SPEED AND MEAN RADIANT TEMPERATURE ON OUTDOOR THERMAL COMFORT OF HUMID TROPICAL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Sangkertadi Sangkertadi

    2016-01-01

    Full Text Available The purposes of this article is to explore knowledge of outdoor thermal comfort in humid tropical environment for urban activities especially for people in walking activity, and those who stationary/seated with moderate action. It will be characterized the pair influence of wind speed and radiant temperature on the outdoor thermal comfort. Many of researchers stated that those two microclimate variables give significant role on outdoor thermal comfort in tropical humid area. Outdoor Tropical Comfort (OTC model was used for simulation in this study. The model output is comfort scale that refers on ASHRAE definition. The model consists of two regression equations with variables of air temperature, globe temperature, wind speed, humidity and body posture, for two types of activity: walking and seated. From the results it can be stated that there is significant role of wind speed to reduce mean radiant temperature and globe temperature, when the velocity is elevated from 0.5 m/s to 2 m/s. However, the wind has not play significant role when the speed is changed from 2 m/s to 3.5 m/s. The results of the study may inspire us to implement effectiveness of electrical-fan equipment for outdoor space in order to get optimum wind speed, coupled with optimum design of shading devices to minimize radiant temperature for thermal comfort.

  18. Fabrication of a capacitive relative humidity sensor using aluminum thin films deposited on etched printed circuit board

    Directory of Open Access Journals (Sweden)

    Lee Jacqueline Ann L.

    2016-01-01

    Full Text Available A capacitive humidity-sensing device was created by thermal evaporation of 99.999% aluminum. The substrate used for the coating was etched double-sided printed circuit board. The etched printed circuit board serves as the dielectric of the capacitor while the aluminum thin films deposited on either side serve as the plates of the capacitor. The capacitance was measured before and after exposure to humidity. The device was then calibrated by comparing the readings of capacitance with that of the relative humidity sensor of the Vernier LabQuest2. It was found that there is a linear relationship between the capacitance and relative humidity given by the equation C=1.418RH+29.139 where C is the capacitance and RH is the relative humidity. The surface of the aluminum films is porous and it is through these pores that water is adsorbed and capillary condensation occurs, thereby causing the capacitance to change upon exposure to humidity.

  19. Fatigue Crack Propagation Behavior of RC Beams Strengthened with CFRP under High Temperature and High Humidity Environment

    Directory of Open Access Journals (Sweden)

    Dongyang Li

    2017-01-01

    Full Text Available Numerical and experimental methods were applied to investigate fatigue crack propagation behavior of reinforced concrete (RC beams strengthened with a new type carbon fiber reinforced polymer (CFRP named as carbon fiber laminate (CFL subjected to hot-wet environment. J-integral of a central crack in the strengthened beam under three-point bending load was calculated by ABAQUS. In finite element model, simulation of CFL-concrete interface was based on the bilinear cohesive zone model under hot-wet environment and indoor atmosphere. And, then, fatigue crack propagation tests were carried out under high temperature and high humidity (50°C, 95% R · H environment pretreatment and indoor atmosphere (23°C, 78% R · H to obtain a-N curves and crack propagation rate, da/dN, of the strengthened beams. Paris-Erdogan formula was developed based on the numerical analysis and environmental fatigue tests.

  20. Defining relative humidity in terms of water activity. Part 1: definition

    Science.gov (United States)

    Feistel, Rainer; Lovell-Smith, Jeremy W.

    2017-08-01

    Relative humidity (RH) is a quantity widely used in various fields such as metrology, meteorology, climatology or engineering. However, RH is neither uniformly defined, nor do some definitions properly account for deviations from ideal-gas properties, nor is the application range of interest fully covered. In this paper, a new full-range definition of RH is proposed that is based on the thermodynamics of activities in order to include deviations from ideal-gas behaviour. Below the critical point of pure water, at pressures p  definition is consistent with de-facto standard RH definitions published previously and recommended internationally. Virial approximations are reported for estimating small corrections to the ideal-gas equations.

  1. Kinetically Determined Hygroscopicity and Efflorescence of Sucrose-Ammonium Sulfate Aerosol Droplets under Lower Relative Humidity.

    Science.gov (United States)

    Wang, Lin-Na; Cai, Chen; Zhang, Yun-Hong

    2017-09-14

    Organic aerosols will likely form in semisolid, glassy, and high viscous state in the atmosphere, which show nonequilibrium kinetic characteristics at low relative humidity (RH) conditions. In this study, we applied optical tweezers to investigate the water transport in a sucrose/(NH 4 ) 2 SO 4 droplet with high organic to inorganic mole ratio (OIR). The characteristic time ratio between the droplet radius and the RH was used to describe the water mass transfer difference dependent on RH. For OIR greater than 1:1 in sucrose/(NH 4 ) 2 SO 4 droplets, the characteristic time ratio at low RH (∼60%). We also coupled vacuum FTIR spectrometer and a high-speed photography to study the efflorescence process in sucrose/(NH 4 ) 2 SO 4 droplets with low OIR. The crystalline fraction of (NH 4 ) 2 SO 4 was used to understand efflorescence behavior when the RH was linearly decreasing with a velocity of 1.2% RH min -1 . Because of suppression of (NH 4 ) 2 SO 4 nucleation by addition of sucrose, the efflorescence relative humidity (ERH) of (NH 4 ) 2 SO 4 decrease from the range of ∼48.2% to ∼36.1% for pure (NH 4 ) 2 SO 4 droplets to from ∼44.7% to ∼25.4%, from ∼43.2% to ∼21.2%, and from ∼41.7% to ∼21.1% for the mixed droplets with OIR of 1:4, 1:3, and 1:2, respectively. No crystallization was observed when the OIR is higher than 1:1. Suppression of (NH 4 ) 2 SO 4 crystal growth was also observed under high viscous sucrose/(NH 4 ) 2 SO 4 droplets at lower RH.

  2. Effect of relative humidity on onset of capillary forces for rough surfaces.

    Science.gov (United States)

    Zarate, Nyah V; Harrison, Aaron J; Litster, James D; Beaudoin, Stephen P

    2013-12-01

    Atomic force microscopy (AFM) was used to investigate the effect of relative humidity (RH) on the adhesion forces between silicon nitride AFM probes, hydrophilic stainless steel, and hydrophobic Perspex® (polymethylmethacrylate, PMMA). In addition, AFM-based phase contrast imaging was used to quantify the amount and location of adsorbed water present on these substrates at RH levels ranging from 15% to 65% at 22°C. Both the adhesion forces and the quantities of adsorbed moisture were seen to vary with RH, and the nature of this variation depended on the hydrophobicity of the substrate. For the Perspex®, both the adhesion force and the amount of adsorbed moisture were essentially independent of RH. For the stainless steel substrate, adsorbed moisture increased continuously with increasing RH, while the adhesion force rose from a minimum at 15% RH to a broad maximum between 25% and 35% RH. From 35% to 55% RH, the adhesion force dropped continuously to an intermediate level before rising again as 65% RH was approached. The changes in adhesion force with increasing relative humidity in the case of the stainless steel substrate were attributed to a balance of effects associated with adsorbed, sub-continuum water on the cantilever and steel. Hydrogen bonding interactions between these adsorbed water molecules were thought to increase the adhesion force. However, when significant quantities of molecular water adsorbed, these molecules were expect to decrease adhesion by screening the van der Waals interactions between the steel and the cantilever tip, and by increasing the separation distance between these solid surfaces when they were 'in contact'. Finally, the slight increase in adhesion between 55% and 65% RH was attributed to true capillary forces exerted by continuum water on the two solid surfaces. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants.

    Science.gov (United States)

    Calvo-Polanco, Monica; Ibort, Pablo; Molina, Sonia; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

    2017-11-01

    The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp o ) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp o in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp o only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp o is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp o to environmental changes.

  4. Calibration and validation processes for relative humidity measurement by a Hygrochron iButton.

    Science.gov (United States)

    Shin, Mirim; Patton, Raymond; Mahar, Trevor; Ireland, Angus; Swan, Paul; Chow, Chin Moi

    2017-10-01

    Accurate relative humidity (RH) measurement is demanded in studies of thermal comfort. Thermal discomfort occurs when the near-to-skin temperature or RH is outside of the thermal comfort zone. The Hygrochron, a small wireless device which measures both temperature and RH, would be suitable and convenient in exercise or sleep studies. However, the RH measurement has not been validated. This paper has three parts. Part 1: In evaluating the sensor surface for RH detection, four Hygrochrons were placed on a wet paper towel. Two were placed on the towel with the protruding surface facing up and the other two facing down. The results showed that the Hygrochron with the protruding side was the sensor surface for detecting RH. Part 2: Twenty-seven Hygrochrons were calibrated in a humidity calibration chamber at a RH range from 40 to 90% at a constant temperature from 32 to 37°C. The mean bias was -1.08% between the Hygrochrons and the calibration chamber. The Hygrochron overestimated RH at the lower range (40-60%) and underestimated RH at the higher range (80-90%). The application of individual regression equations to each Hygrochron improved accuracy and reduced the mean bias to -0.002%. However, one Hygrochron showed outlier values that may be due to a manufacturing defect. Part 3: The reproducibility of Hygrochron for RH measurements was tested twice at the same condition of 35°C over a three-month interval. The intra-class coefficient was 0.996 to 1.000 with non-significant differences in the mean RH between test and re-test results (p=0.159). Hygrochrons are valid for RH measurements which show high reproducibility. It is recommended that Hygrochrons be calibrated over a range of desired RH and temperature prior to use to improve accuracy and detect any manufacturing defects. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

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    M. L. Hinks

    2018-02-01

    Full Text Available The effect of relative humidity (RH on the chemical composition of secondary organic aerosol (SOA formed from low-NOx toluene oxidation in the absence of seed particles was investigated. SOA samples were prepared in an aerosol smog chamber at < 2 % RH and 75 % RH, collected on Teflon filters, and analyzed with nanospray desorption electrospray ionization high-resolution mass spectrometry (nano-DESI–HRMS. Measurements revealed a significant reduction in the fraction of oligomers present in the SOA generated at 75 % RH compared to SOA generated under dry conditions. In a separate set of experiments, the particle mass concentrations were measured with a scanning mobility particle sizer (SMPS at RHs ranging from < 2 to 90 %. It was found that the particle mass loading decreased by nearly an order of magnitude when RH increased from < 2 to 75–90 % for low-NOx toluene SOA. The volatility distributions of the SOA compounds, estimated from the distribution of molecular formulas using the molecular corridor approach, confirmed that low-NOx toluene SOA became more volatile on average under high-RH conditions. In contrast, the effect of RH on SOA mass loading was found to be much smaller for high-NOx toluene SOA. The observed increase in the oligomer fraction and particle mass loading under dry conditions were attributed to the enhancement of condensation reactions, which produce water and oligomers from smaller compounds in low-NOx toluene SOA. The reduction in the fraction of oligomeric compounds under humid conditions is predicted to partly counteract the previously observed enhancement in the toluene SOA yield driven by the aerosol liquid water chemistry in deliquesced inorganic seed particles.

  6. Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity

    Science.gov (United States)

    Chmura, Paweł; Konefał, Marek; Andrzejewski, Marcin; Kosowski, Jakub; Rokita, Andrzej; Chmura, Jan

    2017-04-01

    The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % ( p ≤ 0.001). Two-way ANOVA revealed significant differences ( p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

  7. Ingestion of a cold temperature/menthol beverage increases outdoor exercise performance in a hot, humid environment.

    Science.gov (United States)

    Tran Trong, Than; Riera, Florence; Rinaldi, Kévin; Briki, Walid; Hue, Olivier

    2015-01-01

    A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions. Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol) beverage at three temperatures: Neutral (ambient temperature) (28.7°C±0. 5°C), Cold (3.1°C±0.6°C) or Ice-slurry (0.17°C±0.07°C). Trial time, core temperature (Tco), heart rate (HR), rate of perceived exertion (RPE), thermal sensation (TS) and thermal comfort (TC) were assessed. Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol. A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone). Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE) between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.

  8. Ingestion of a cold temperature/menthol beverage increases outdoor exercise performance in a hot, humid environment.

    Directory of Open Access Journals (Sweden)

    Than Tran Trong

    Full Text Available A recent laboratory study demonstrated that the ingestion of a cold/menthol beverage improved exercise performance in a hot and humid environment during 20 km of all-out cycling. Therefore, the aim of this study was to determine whether the ingestion of cold water/ice-slurry with menthol would improve performance in hot and humid outdoor conditions.Ten trained males completed three trials of five blocks consisting of 4-km cycling and 1.5-km running. During warm-up, every block and recovery, the athletes drank 190 ml of aromatized (i.e., with 0.05 mL of menthol beverage at three temperatures: Neutral (ambient temperature (28.7°C±0. 5°C, Cold (3.1°C±0.6°C or Ice-slurry (0.17°C±0.07°C. Trial time, core temperature (Tco, heart rate (HR, rate of perceived exertion (RPE, thermal sensation (TS and thermal comfort (TC were assessed.Ice-slurry/menthol increased performance by 6.2% and 3.3% compared with neutral water/menthol and cold water/menthol, respectively. No between-trial differences were noted for Tco, HR, RPE, TC and TS was lower with ice-slurry/menthol and cold water/menthol compared with neutral water/menthol.A low drink temperature combined with menthol lessens the performance decline in hot/humid outdoor conditions (i.e., compared with cold water alone. Performances were better with no difference in psycho-physiological stress (Tco, HR and RPE between trials. The changes in perceptual parameters caused by absorbing a cold/menthol beverage reflect the psychological impact. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.

  9. Water repellence assessment in humid mediterranean carbonated environments: influence of shrubland species

    Science.gov (United States)

    Oscar, Gonzalez-Pelayo; Vicente, Andreu; Luis, Rubio Jose; Carla Sofia, Ferreira; Dinis, Ferreira Antonio Jose

    2010-05-01

    The importance of natural or induced (fire) water repellence in terms of water redistribution in the soil profile, reduction in soil infiltration capacity and thus, in runoff magnification, is well established. Hydrophobicity has been identified around the world in different climatic conditions, land covers, soil and vegetation types. Regarding soil and vegetation, many studies are based on coarse acidic soils with pine forest, eucalyptus, deciduous trees, grassland, cropland, chaparral vegetation type, and lately in shrublands. However, few studies are related to shrubland in wet Mediterranean carbonated environments. This work is oriented to the study of soil water repellence in these environments by means of WDPT. The study was carried out in Podentes (Coimbra), central Portugal, on 4 ha of shrubland (mainly Quercus coccifera, Pistacia lentiscus and Arbutus unedo), developed on Umbric leptosol and Calcaric cambisol soil types (WRB). The WDPT was assessed depending on the shrubland type, slope orientation, soil depth (0-2 cm and 2-5 cm) and on different soil fractions (unedo. Soil water repellence decreased with depth. The studied shrubland species showed an increasing trend on the soil hydrophobicity persistence: A. unedo > Q. coccifera ≈ P. lentiscus; and depending on the orientation: NE > SW. Direct relationships were obtained between the soil organic matter content and the log WDPT on almost all the surface soil samples. The soil pH and carbonate content did not display correlation with soil water repellence. The different hydrophobic compounds generated by waxes and resins of the different shrubland types, which could be incorporated to the soil as binding agents, seem to be the explanation for the differences of the WDPT data. The patchy distribution of the vegetation rules the persistence of the natural soil water repellence, restraining water infiltration mainly by micropore flow, being then the soil hydrology controlled by the macropore flow, cracks

  10. Influence of relative humidity of air on the level of aqueous tritium in corn, wheat and sunflower

    International Nuclear Information System (INIS)

    Indeka, L.

    1981-01-01

    The short-term changes in level of aqueous tritium in the leaves in relation to the air humidity were studied. The experiments were carried out on corn in which the transpiration is relatively small, on sunflower with very high transpiration and on wheat with intermediate transpiration. (M.F.W.)

  11. Relative humidity and its effect on aerosol optical depth in the vicinity of convective clouds

    International Nuclear Information System (INIS)

    Altaratz, O; Bar-Or, R Z; Wollner, U; Koren, I

    2013-01-01

    The hygroscopic growth of aerosols is controlled by the relative humidity (RH) and changes the aerosols’ physical and hence optical properties. Observational studies of aerosol–cloud interactions evaluate the aerosol concentration using optical parameters, such as the aerosol optical depth (AOD), which can be affected by aerosol humidification. In this study we evaluate the RH background and variance values, in the lower cloudy atmosphere, an additional source of variance in AOD values beside the natural changes in aerosol concentration. In addition, we estimate the bias in RH and AOD, related to cloud thickness. This provides the much needed range of RH-related biases in studies of aerosol–cloud interaction. Twelve years of radiosonde measurements (June–August) in thirteen globally distributed stations are analyzed. The estimated non-biased AOD variance due to day-to-day changes in RH is found to be around 20% and the biases linked to cloud development around 10%. Such an effect is important and should be considered in direct and indirect aerosol effect estimations but it is inadequate to account for most of the AOD trend found in observational studies of aerosol–cloud interactions. (letter)

  12. The effects of temperature, relative humidity, light, and resource quality on flight initiation in the red flour beetle, Tribolium castaneum.

    Science.gov (United States)

    Drury, Douglas W; Whitesell, Matthew E; Wade, Michael J

    2016-03-01

    We investigated the environmental conditions that induce a flight response in the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), including resource quality, temperature, relative humidity, and light. Over 72-h trial periods, we observed the proportion of individuals emigrating by flight to range from 0.0 in extreme heat or cold to 0.82 with starvation. Resource quality, presence of a light source, and temperature all directly influenced the initiation of the flight response. We did not detect any effect of relative humidity or sudden change in temperature on the incidence of flight. We discuss our findings in the context of Tribolium ecology and evolution.

  13. Investigation of the influence of the microcapillary structure of natural skins on relative humidity in vacuum-sorption humidification

    Directory of Open Access Journals (Sweden)

    Larina Ludmila

    2017-01-01

    Full Text Available The article presents the results of studies confirming the law of the gamma distribution of microcapillaries in the structure of materials having a stochastic structure, for example, natural skins. The relative humidity of the latter depends on the mass of moisture collected by the microcapillaries, with heat and mass transfer under vacuum conditions. Numerical values of relative humidity in this case may differ from those recommended by footwear manufacturing technologies and should be considered as an integral part of the phenomenon of high-intensity heat and mass transfer under vacuum conditions and be determined by the proposed models.

  14. Night ventilation at courtyard housing estate in warm humid tropic for sustainable environment

    Science.gov (United States)

    Defiana, Ima; Teddy Badai Samodra, FX; Setyawan, Wahyu

    2018-03-01

    The problem in the night-time for warm humid tropic housing estate is thermal discomfort. Heat gains accumulation from building envelope, internal heat gains and activities of occupants influence indoor thermal comfort. Ventilation is needed for transfer or removes heat gains accumulation to outdoor. This study describes the role of an inner courtyard to promote pressure difference. Pressure difference as a wind driven force to promote wind velocity thereby could transfer indoor heat gains accumulation to outdoor of building. A simulation used as the research method for prediction wind velocity. Purposive sampling used as the method to choose building sample with similar inner courtyards. The field survey was conducted to obtain data of inner courtyard typologies and two housing were used as model simulation. Furthermore, the simulation is running in steady state mode, at 05.00 pm when the occupants usually close window. But the window should be opened in the night-time to transfer indoor heat gain to outdoor. The result shows that the factor influencing physiological cooling as consequences of inner courtyard are height to width ratio, the distance between inner courtyard to windward, window configuration and the inner courtyard design-the proportion between the length, the width, and the height.

  15. Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China

    Science.gov (United States)

    Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A.; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

    2016-01-01

    Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids. PMID:26829756

  16. Observed changes in relative humidity and dew point temperature in coastal regions of Iran

    Science.gov (United States)

    Hosseinzadeh Talaee, P.; Sabziparvar, A. A.; Tabari, Hossein

    2012-12-01

    The analysis of trends in hydroclimatic parameters and assessment of their statistical significance have recently received a great concern to clarify whether or not there is an obvious climate change. In the current study, parametric linear regression and nonparametric Mann-Kendall tests were applied for detecting annual and seasonal trends in the relative humidity (RH) and dew point temperature ( T dew) time series at ten coastal weather stations in Iran during 1966-2005. The serial structure of the data was considered, and the significant serial correlations were eliminated using the trend-free pre-whitening method. The results showed that annual RH increased by 1.03 and 0.28 %/decade at the northern and southern coastal regions of the country, respectively, while annual T dew increased by 0.29 and 0.15°C per decade at the northern and southern regions, respectively. The significant trends were frequent in the T dew series, but they were observed only at 2 out of the 50 RH series. The results showed that the difference between the results of the parametric and nonparametric tests was small, although the parametric test detected larger significant trends in the RH and T dew time series. Furthermore, the differences between the results of the trend tests were not related to the normality of the statistical distribution.

  17. The Influence of Relative Humidity on Dielectric Barrier Discharge Plasma Flow Control Actuator Performance

    Science.gov (United States)

    Wicks, M.; Thomas, F. O.; Corke, T. C.; Patel, M.

    2012-11-01

    Dielectric barrier discharge (DBD) plasma actuators possess numerous advantages for flow control applications and have been the focus of several previous studies. Most work has been performed in relatively pristine laboratory settings. In actual flow control applications, however, it is essential to assess the impact of various environmental influences on actuator performance. As a first effort toward assessing a broad range of environmental effects on DBD actuator performance, the influence of relative humidity (RH) is considered. Actuator performance is quantified by force balance measurements of reactive thrust while RH is systematically varied via an ultrasonic humidifier. The DBD plasma actuator assembly, force balance, and ultrasonic humidifier are all contained inside a large, closed test chamber instrumented with RH and temperature sensors in order to accurately estimate the average RH at the actuator. Measurements of DBD actuator thrust as a function of RH for several different applied voltage regimes and dielectric materials and thicknesses are presented. Based on these results, several important design recommendations are made. This work was supported by Innovative Technology Applications Company (ITAC), LLC under a Small Business Innovation Research (SBIR) Phase II Contract No. N00014-11-C-0267 issued by the U.S. Department of the Navy.

  18. What Governs Friction of Silicon Oxide in Humid Environment: Contact Area between Solids, Water Meniscus around the Contact, or Water Layer Structure?

    Science.gov (United States)

    Chen, Lei; Xiao, Chen; Yu, Bingjun; Kim, Seong H; Qian, Linmao

    2017-09-26

    In order to understand the interfacial parameters governing the friction force (F t ) between silicon oxide surfaces in humid environment, the sliding speed (v) and relative humidity (RH) dependences of F t were measured for a silica sphere (1 μm radius) sliding on a silicon oxide (SiO x ) surface, using atomic force microscopy (AFM), and analyzed with a mathematical model describing interfacial contacts under a dynamic condition. Generally, F t decreases logarithmically with increasing v to a cutoff value below which its dependence on interfacial chemistry and sliding condition is relatively weak. Above the cutoff value, the logarithmic v dependence could be divided into two regimes: (i) when RH is lower than 50%, F t is a function of both v and RH; (ii) in contrast, at RH ≥ 50%, F t is a function of v only, but not RH. These complicated v and RH dependences were hypothesized to originate from the structure of the water layer adsorbed on the surface and the water meniscus around the annulus of the contact area. This hypothesis was tested by analyzing F t as a function of the water meniscus area (A m ) and volume (V m ) estimated from a thermally activated water-bridge formation model. Surprisingly, it was found that F t varies linearly with V m and correlates poorly with A m at RH contact under ambient conditions.

  19. Coupled effects of the temperature and the relative humidity on gecko adhesion

    International Nuclear Information System (INIS)

    Peng, Zhilong; Yang, Yazheng; Chen, Shaohua

    2017-01-01

    To explain the inconsistent results of experiments on temperature-dependent gecko adhesion, a theoretical peeling model is established wherein a nano-thin film is adopted to simulate a gecko spatula. The model considers not only the respective effects of temperature and environmental humidity on the peel-off force but also the coupled effect of both factors. Increasing temperature is found to lead to a decreasing peel-off force if the environmental humidity is uncontrolled. However, if the environmental humidity is constant, the peel-off force is insensitive to the temperature and remains almost constant. The synthetic theoretical analysis demonstrates that the seemingly contradictory results of temperature-dependent gecko adhesion experiments are actually consistent under their respective experimental conditions. This inconsistency is mainly due to the environmental humidity, which varies with the changing temperature if it is not artificially controlled. The results cannot only reasonably explain the different experimental results for the effect of temperature on gecko adhesion but can also facilitate the design of temperature-controlled or humidity-controlled adhesion sensors by tuning the environmental humidity or temperature. (paper)

  20. The influence of air temperature and relative humidity on dynamics of water potential in Betula pendula (Betulaceae trees

    Directory of Open Access Journals (Sweden)

    G. P. Тikhova

    2017-02-01

    Full Text Available Linear multiple models were developed to describe diurnal and seasonal dynamics of water potential (Ψ of the foliated shoots in the plants of Betula genus related to air temperature and relative humidity in the middle taiga (southern Karelia. The results of the study revealed unidirectional changes, but different effect strength of air temperature and relative humidity on Ψ of the foliated shoots of common silver birch (Betula pendula Roth and curly (Karelian birch (Betula pendula Roth var. carelica. It was shown that increasing air temperature 1°С results in similar decreasing of Ψ value equal to 0.037–0.038 MPa in both of the birches (p > 0.05. Since the diurnal air temperature range achieves 10–15 °С, the contribution of this factor may be up to 0.57 MPa. On the contrary, the contribution of relative air humidity to Ψ value differs significantly in distinct birch forms (p < 0.05. In this case the change range of Ψ value in silver birch and curly birch may be up to 0.46 (0.015 MPa/1 % RH and 0.52 МПа (0.017 MPa/1 % RH, respectively. The results indicate that curly birch responds to the increase of relative air humidity with higher magnification of Ψ in comparison with common silver birch.

  1. Absorbing aerosols at high relative humidity: linking hygroscopic growth to optical properties

    Directory of Open Access Journals (Sweden)

    J. Michel Flores

    2012-06-01

    Full Text Available One of the major uncertainties in the understanding of Earth's climate system is the interaction between solar radiation and aerosols in the atmosphere. Aerosols exposed to high humidity will change their chemical, physical, and optical properties due to their increased water content. To model hydrated aerosols, atmospheric chemistry and climate models often use the volume weighted mixing rule to predict the complex refractive index (RI of aerosols when they interact with high relative humidity, and, in general, assume homogeneous mixing. This study explores the validity of these assumptions. A humidified cavity ring down aerosol spectrometer (CRD-AS and a tandem hygroscopic DMA (differential mobility analyzer are used to measure the extinction coefficient and hygroscopic growth factors of humidified aerosols, respectively. The measurements are performed at 80% and 90%RH at wavelengths of 532 nm and 355 nm using size-selected aerosols with different degrees of absorption; from purely scattering to highly absorbing particles. The ratio of the humidified to the dry extinction coefficients (fRHext(%RH, Dry is measured and compared to theoretical calculations based on Mie theory. Using the measured hygroscopic growth factors and assuming homogeneous mixing, the expected RIs using the volume weighted mixing rule are compared to the RIs derived from the extinction measurements.

    We found a weak linear dependence or no dependence of fRH(%RH, Dry with size for hydrated absorbing aerosols in contrast to the non-monotonically decreasing behavior with size for purely scattering aerosols. No discernible difference could be made between the two wavelengths used. Less than 7% differences were found between the real parts of the complex refractive indices derived and those calculated using the volume weighted mixing rule, and the imaginary parts had up to a 20% difference. However, for substances with growth factor less than 1

  2. UV Raman lidar measurements of relative humidity for the characterization of cirrus cloud microphysical properties

    Directory of Open Access Journals (Sweden)

    G. Masiello

    2009-11-01

    Full Text Available Raman lidar measurements performed in Potenza by the Raman lidar system BASIL in the presence of cirrus clouds are discussed. Measurements were performed on 6 September 2004 in the frame of the Italian phase of the EAQUATE Experiment.

    The major feature of BASIL is represented by its capability to perform high-resolution and accurate measurements of atmospheric temperature and water vapour, and consequently relative humidity, both in daytime and night-time, based on the application of the rotational and vibrational Raman lidar techniques in the UV. BASIL is also capable to provide measurements of the particle backscatter and extinction coefficient, and consequently lidar ratio (at the time of these measurements, only at one wavelength, which are fundamental to infer geometrical and microphysical properties of clouds.

    A case study is discussed in order to assess the capability of Raman lidars to measure humidity in presence of cirrus clouds, both below and inside the cloud. While air inside the cloud layers is observed to be always under-saturated with respect to water, both ice super-saturation and under-saturation conditions are found inside these clouds. Upper tropospheric moistening is observed below the lower cloud layer.

    The synergic use of the data derived from the ground based Raman Lidar and of spectral radiances measured by the NAST-I Airborne Spectrometer allows the determination of the temporal evolution of the atmospheric cooling/heating rates due to the presence of the cirrus cloud.

    Lidar measurements beneath the cirrus cloud layer have been interpreted using a 1-D cirrus cloud model with explicit microphysics. The 1-D simulations indicate that sedimentation-moistening has contributed significantly to the moist anomaly, but other mechanisms are also contributing. This result supports the hypothesis that the observed mid-tropospheric humidification is a real feature which is

  3. Temperature and Relative Humidity Vertical Profiles within Planetary Boundary Layer in Winter Urban Airshed

    Science.gov (United States)

    Bendl, Jan; Hovorka, Jan

    2017-12-01

    The planetary boundary layer is a dynamic system with turbulent flow where horizontal and vertical air mixing depends mainly on the weather conditions and geomorphology. Normally, air temperature from the Earth surface decreases with height but inversion situation may occur, mainly during winter. Pollutant dispersion is poor during inversions so air pollutant concentration can quickly rise, especially in urban closed valleys. Air pollution was evaluated by WHO as a human carcinogen (mostly by polycyclic aromatic hydrocarbons) and health effects are obvious. Knowledge about inversion layer height is important for estimation of the pollution impact and it can give us also information about the air pollution sources. Temperature and relative humidity vertical profiles complement ground measurements. Ground measurements were conducted to characterize comprehensively urban airshed in Svermov, residential district of the city of Kladno, about 30 km NW of Prague, from the 2nd Feb. to the 3rd of March 2016. The Svermov is an air pollution hot-spot for long time benzo[a]pyrene (B[a]P) limit exceedances, reaching the highest B[a]P annual concentration in Bohemia - west part of the Czech Republic. Since the Svermov sits in a shallow valley, frequent vertical temperature inversion in winter and low emission heights of pollution sources prevent pollutant dispersal off the valley. Such orography is common to numerous small settlements in the Czech Republic. Ground measurements at the sports field in the Svermov were complemented by temperature and humidity vertical profiles acquired by a Vaisala radiosonde positioned at tethered He-filled balloon. Total number of 53 series of vertical profiles up to the height of 300 m was conducted. Meteorology parameters were acquired with 4 Hz frequency. The measurements confirmed frequent early-morning and night formation of temperature inversion within boundary layer up to the height of 50 m. This rather shallow inversion had significant

  4. Effects of relative humidity on the characterization of a photochemical smog chamber.

    Science.gov (United States)

    Hu, Gaoshuo; Xu, Yongfu; Jia, Long

    2011-01-01

    Water vapor plays an important role in many atmospheric chemical reactions. A self-made indoor environmental smog chamber was used to investigate the effects of relative humidity (RH) on its characterization, which included the wall effects of reactive species such as 03 and NOx, and the determination of chamber-dependent OH radicals in terms of CO-NOx irradiation experiments. Results showed that the rate constant of O3 wall losses increased with increasing RH, and that their relationship was linearly significant. Although RH affected the rate constant of NOx wall losses, their relationship was not statistically significant. Background air generated a small amount of ozone at both high and low RH. When RH varied from 5% to 79%, the apparent rate constant kNO2-->HONO for the conversion of NO2 into gas phase HONO was estimated in the range of 0.70 x 10(-3)-2.5 x 10(-3) min(-1). A linear relationship between kNO2-->HONO and RH was obtained as kNO2-->HONO (10(-3) min(-1)) = -0.0255RH + 2.64, with R2 and P value being 0.978 and < 0.01. To our knowledge, this is the first report on their relationship. The generation mechanism for HONO and OH was also discussed in this work.

  5. Sulfuric acid nucleation: power dependencies, variation with relative humidity, and effect of bases

    Directory of Open Access Journals (Sweden)

    J. H. Zollner

    2012-05-01

    Full Text Available Nucleation of particles composed of sulfuric acid, water, and nitrogen base molecules was studied using a continuous flow reactor. The particles formed from these vapors were detected with an ultrafine condensation particle counter, while vapors of sulfuric acid and nitrogen bases were detected by chemical ionization mass spectrometry. Variation of particle numbers with sulfuric acid concentration yielded a power dependency on sulfuric acid of 5 ± 1 for relative humidities of 14–68% at 296 K; similar experiments with varying water content yielded power dependencies on H2O of ~7. The critical cluster contains about 5 H2SO4 molecules and a new treatment of the power dependency for H2O suggests about 12 H2O molecules for these conditions. Addition of 2-to-45 pptv of ammonia or methyl amine resulted in up to millions of times more particles than in the absence of these compounds. Particle detection capabilities, sulfuric acid and nitrogen base detection, wall losses, and the extent of particle growth are discussed. Results are compared to previous laboratory nucleation studies and they are also discussed in terms of atmospheric nucleation scenarios.

  6. Temperature and relative humidity influence the ripening descriptors of Camembert-type cheeses throughout ripening.

    Science.gov (United States)

    Leclercq-Perlat, M-N; Sicard, M; Perrot, N; Trelea, I C; Picque, D; Corrieu, G

    2015-02-01

    Ripening descriptors are the main factors that determine consumers' preferences of soft cheeses. Six descriptors were defined to represent the sensory changes in Camembert cheeses: Penicillium camemberti appearance, cheese odor and rind color, creamy underrind thickness and consistency, and core hardness. To evaluate the effects of the main process parameters on these descriptors, Camembert cheeses were ripened under different temperatures (8, 12, and 16°C) and relative humidity (RH; 88, 92, and 98%). The sensory descriptors were highly dependent on the temperature and RH used throughout ripening in a ripening chamber. All sensory descriptor changes could be explained by microorganism growth, pH, carbon substrate metabolism, and cheese moisture, as well as by microbial enzymatic activities. On d 40, at 8°C and 88% RH, all sensory descriptors scored the worst: the cheese was too dry, its odor and its color were similar to those of the unripe cheese, the underrind was driest, and the core was hardest. At 16°C and 98% RH, the odor was strongly ammonia and the color was dark brown, and the creamy underrind represented the entire thickness of the cheese but was completely runny, descriptors indicative of an over ripened cheese. Statistical analysis showed that the best ripening conditions to achieve an optimum balance between cheese sensory qualities and marketability were 13±1°C and 94±1% RH. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Dynamics of spatial heterogeneity of stomatal closure in Tradescantia virginiana altered by growth at high relative air humidity

    NARCIS (Netherlands)

    Rezaei Nejad, A.; Harbinson, J.; Meeteren, van U.

    2006-01-01

    The spatial heterogeneity of stomatal closure in response to rapid desiccation of excised well-watered Tradescantia virginiana leaves grown at moderate (55%) or high (90%) relative air humidity (RH) was studied using a chlorophyll fluorescence imaging system under non-photorespiratory conditions.

  8. Influence of the relative humidity and the temperature on the in-vivo friction behaviour of human skin

    NARCIS (Netherlands)

    Klaassen, M.; Schipper, D. J.; Masen, M.A.

    2016-01-01

    Both temperature and relative humidity are known to influence the frictional behaviour of human skin. However, literature does not completely cover to what extent both parameters play a role. Measurements were conducted using an in-house built reciprocating tribometer inside an enclosure in which

  9. Modeling the effects of temperature and relative humidity on gas exchange of prickly pear cactus (Opuntia spp.) stems

    NARCIS (Netherlands)

    Guevara-Arauza, J.C.; Yahia, E.M.; Cedeno, L.; Tijskens, L.M.M.

    2006-01-01

    A model to estimate gas profile of modified atmosphere packaged (MAP) prickly pear cactus stems was developed and calibrated. The model describes the transient gas exchange taking in consideration the effect of temperature (T) and relative humidity (RH) on film permeability (FPgas), respiration rate

  10. Cotton Flowers: Pollen and Petal Humidity Sensitivities Determine Reproductive Competitiveness in Diverse Environments

    Science.gov (United States)

    Genetic diversity in reproductive abiotic stress tolerance has been reported for cotton [Gossypium hirsutum (L.)] based upon the percentage of anther dehiscence of mature pollen in adverse environments. This study investigated the abiotic stress tolerance of mature pollen and identified genetic vari...

  11. Relative effect of solder flux chemistry on the humidity related failures in electronics

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-01-01

    Purpose - This paper aims to investigate the effect of no-clean flux chemistry with various weak organic acids (WOAs) as activators on the corrosion reliability of electronics with emphasis on the hygroscopic nature of the residue. Design/methodology/approach - The hygroscopicity of flux residue...... in the impedance measurements were observed. Practical implications - The findings are attributed to the deliquescence RH of the WOA(s) in the flux and chemistry of water-layer formation. The results show the importance of WOA type in relation to its solubility and deliquescence RH on the corrosion reliability...

  12. The effect of clothing fit and material of women’s Islamic sportswear on physiological and subjective responses during exercise in warm and humid environment

    Directory of Open Access Journals (Sweden)

    Wibowo Astrid Wahyu Adventri

    2018-01-01

    Full Text Available The purpose of this study was to investigate the effects of clothing fit and material of Islamic sportswear for female on physiological responses and body heat balance during exercise in warm and humid environment. Twelve healthy female students (20.3±0.4 years exercised wearing four types of women’s Islamic sportswear comprised of two level of clothing fit: loose-fit and tight-fit, and two types of material for sportswear: cotton and polyester on four separate occasions, and in random order. They performed a 30-min treadmill exercise at an intensity of 70% HRmax and then rested on a chair for 20 min for recovery in a chamber set at an ambient temperature of 34°C and relative humidity of 80%. The results showed that clothing fit did not significantly affect physiological and subjective responses, but clothing material did; sportswear made of cotton resulted in a higher increase of tympanic temperature during exercise and recovery compared to that made of polyester (P<0.05. In addition, sportswear made of cotton have lower conductive and evaporative heat loss than sportswear made of polyester (P<0.05. Clothing fit only had significant effect on conductive heat loss; that is tight-fit sportswear showed greater conductive heat loss than loose-fit one (P <0.05. Regarding subjective responses, participants reported lower thermal comfort, greater thermal sensation, and greater skin wetness sensation when performing exercise wearing tight-fit sportswear made of polyester.

  13. Lower-tropospheric humidity: climatology, trends and the relation to the ITCZ

    Directory of Open Access Journals (Sweden)

    Alexander Läderach

    2013-07-01

    Full Text Available The tropical region is an area of maximum humidity and serves as the major humidity source of the globe. Among other phenomena, it is governed by the so-called Inter-Tropical Convergence Zone (ITCZ which is commonly defined by converging low-level winds or enhanced precipitation. Given its importance as a humidity source, we investigate the humidity fields in the tropics in different reanalysis data sets, deduce the climatology and variability and assess the relationship to the ITCZ. Therefore, a new analysis method of the specific humidity distribution is introduced which allows detecting the location of the humidity maximum, the strength and the meridional extent. The results show that the humidity maximum in boreal summer is strongly shifted northward over the warm pool/Asia Monsoon area and the Gulf of Mexico. These shifts go along with a peak in the strength in both areas; however, the extent shrinks over the warm pool/Asia Monsoon area, whereas it is wider over the Gulf of Mexico. In winter, such connections between location, strength and extent are not found. Still, a peak in strength is again identified over the Gulf of Mexico in boreal winter. The variability of the three characteristics is dominated by inter-annual signals in both seasons. The results using ERA-interim data suggest a positive trend in the Gulf of Mexico/Atlantic region from 1979 to 2010, showing an increased northward shift in the recent years. Although the trend is only weakly confirmed by the results using MERRA reanalysis data, it is in phase with a trend in hurricane activity – a possible hint of the importance of the new method on hurricanes. Furthermore, the position of the maximum humidity coincides with one of the ITCZ in most areas. One exception is the western and central Pacific, where the area is dominated by the double ITCZ in boreal winter. Nevertheless, the new method enables us to gain more insight into the humidity distribution, its variability and

  14. circadian rhythm of calling behavior in the emei music frog (babina daunchina)is associated with habitat temperature and relative humidity

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    generally,the function of vocalizations made by male anurans are to attract females or defend resources.typically,males vocalize in choruses during one or more periods in a twenty-four-hour cycle,which varies,however,among species.nevertheless,the causal factors influencing circadian variations of calling patterns in anuran species are not clear.in this study,male chorus vocalizations were monitored in the emei music frog (babina daunchina)for 17 consecutive days during the breeding season,while its habitat air temperature and relative humidity in the course of experiments were measured as well.the results revealed that the circadian calling patterns were characterized by two periods of peak vocalization,which were observed from 0500 h to 0700 h and from 1300 h to 2000 h,while the lowest activity period was found from 2100 h to 2200 h.both calls/h and notes/h were positively correlated with air temperature and negatively with relative humidity.overall,our data indicate that the emei music frogs (b.daunchina)could regulate their vocal activities based on the changes of physical micro-environment (e.g.,temperature or humidity)to maximize reproductive success.

  15. Trends in mean maximum temperature, mean minimum temperature and mean relative humidity for Lautoka, Fiji during 2003 – 2013

    Directory of Open Access Journals (Sweden)

    Syed S. Ghani

    2017-12-01

    Full Text Available The current work observes the trends in Lautoka’s temperature and relative humidity during the period 2003 – 2013, which were analyzed using the recently updated data obtained from Fiji Meteorological Services (FMS. Four elements, mean maximum temperature, mean minimum temperature along with diurnal temperature range (DTR and mean relative humidity are investigated. From 2003–2013, the annual mean temperature has been enhanced between 0.02 and 0.080C. The heating is more in minimum temperature than in maximum temperature, resulting in a decrease of diurnal temperature range. The statistically significant increase was mostly seen during the summer months of December and January. Mean Relative Humidity has also increased from 3% to 8%. The bases of abnormal climate conditions are also studied. These bases were defined with temperature or humidity anomalies in their appropriate time sequences. These established the observed findings and exhibited that climate has been becoming gradually damper and heater throughout Lautoka during this period. While we are only at an initial phase in the probable inclinations of temperature changes, ecological reactions to recent climate change are already evidently noticeable. So it is proposed that it would be easier to identify climate alteration in a small island nation like Fiji.

  16. Artificial groundwater recharge as integral part of a water resources system in a humid environment

    Science.gov (United States)

    Kupfersberger, Hans; Stadler, Hermann

    2010-05-01

    managed aquifer recharge system have been evaluated. Among numerous results it could be shown that replacing the lawn by sand basins and operating them constantly during winter holds the largest potential to increase the infiltration volume. However, this is only an option for new to build structures since the current basin positions would lead to large direct losses of recharged groundwater into the river Mur. Adjusting the timing of infiltration and withdrawal based on subsurface travel time yields an increase of the pumped amount of about 11% given about the same extension the wells' capture zones. The overall costs of artificial groundwater recharge amount to 0,15 €/m³ excluding pumping and distribution costs compared to a water price of about 1,5 €/m³ charged to consumers. Currently, the implications of building a hydro power plant adjacent to the recharge site are evaluated emphasizing the need for innovative solutions given only limited land resources. On the basis of the projected impacts of climate change on the availability of surface water and groundwater in the South-Eastern alpine regions, the aquifers can act as a buffer system to help overcome the timely shift between supply and demand. Thus, also in predominantly humid regions artificial groundwater recharge represents a viable and sustainable solution to safeguard the supply of drinking water in the long term.

  17. A distribution law for relative humidity in the upper troposphere and lower stratosphere derived from three years of MOZAIC measurements

    Directory of Open Access Journals (Sweden)

    K. Gierens

    1999-09-01

    Full Text Available Data from three years of MOZAIC measurements made it possible to determine a distribution law for the relative humidity in the upper troposphere and lower stratosphere. Data amounting to 13.5% of the total were obtained in regions with ice supersaturation. Troposphere and stratosphere are distinguished by an ozone concentration of 130 ppbv as threshold. The probability of measuring a certain amount of ice supersaturation in the troposphere decreases exponentially with the degree of ice supersaturation. The probability of measuring a certain relative humidity in the stratosphere (both with respect to water and ice decreases exponentially with the relative humidity. A stochastic model that naturally leads to the exponential distribution is provided. Mean supersaturation in the troposphere is about 15%, whereas ice nucleation requires 30% supersaturation on the average. This explains the frequency of regions in which aircraft induce persistent contrails but which are otherwise free of clouds. Ice supersaturated regions are 3-4 K colder and contain more than 50% more vapour than other regions in the upper troposphere. The stratospheric air masses sampled are dry, as expected, having mean relative humidity over water of 12% and over ice of 23%, respectively. However, 2% of the stratospheric data indicate ice supersaturation. As the MOZAIC measurements have been obtained on commercial flights mainly between Europe and North America, the data do not provide a complete global picture, but the exponential character of the distribution laws found is probably valid globally. Since water vapour is the most important greenhouse gas and since it might enhance the anthropogenic greenhouse effects via positive feedback mechanisms, it is important to represent its distribution correctly in climate models. The discovery of the distribution law of the relative humidity makes possible simple tests to show whether the hydrological cycle in climate models is

  18. New Submersed Chamber for Calibration of Relative Humidity Instruments at HMI/FSB-LPM

    Science.gov (United States)

    Sestan, D.; Zvizdic, D.; Sariri, K.

    2018-02-01

    This paper gives a detailed description of a new chamber designed for calibration of relative humidity (RH) instruments at Laboratory for Process Measurement (HMI/FSB-LPM). To the present time, the calibrations of RH instruments at the HMI/FSB-LPM were done by comparison method using a climatic chamber of large volume and calibrated dew point hygrometer with an additional thermometer. Since 2010, HMI/FSB-LPM in cooperation with Centre for Metrology and Accreditation in Finland (MIKES) developed the two primary dew point generators which cover the dew point temperature range between - 70 {°}C and 60 {°}C. In order to utilize these facilities for calibrations of the RH instruments, the new chamber was designed, manufactured and installed in the existing system, aiming to extend its range and reduce the related calibration uncertainties. The chamber construction allows its use in a thermostatic bath of larger volume as well as in the climatic chambers. In the scope of this paper, performances of the new chamber were tested while it was submersed in a thermostated bath. The chamber can simultaneously accommodate up to three RH sensors. In order to keep the design of the chamber simple, only cylindrical RH sensors detachable from display units can be calibrated. Possible optimizations are also discussed, and improvements in the design proposed. By using the new chamber, HMI/FSB-LPM reduced the expanded calibration uncertainties (level of confidence 95 %, coverage factor k=2) from 0.6 %rh to 0.25 %rh at 30 %rh (23 {°}C), and from 0.8 %rh to 0.53 %rh at 70 %rh (23 {°}C).

  19. Objective and Subjective Responses to Low Relative Humidity in an Office Intervention Study

    DEFF Research Database (Denmark)

    Lagercrantz, Love Per; Wyon, David; Meyer, H. W.

    2003-01-01

    and objective (clinical) measurements were applied. The following effects of increased humidity were significant, though small: the air was evaluated as less dry (though still on the dry side of neutral), eyes smarted less (by 10% of full scale) eye irritation decreased (by 11%), symptoms of dry throat, mouth......The impact of dry indoor air on comfort and health in winter was investigated in a crossover intervention study in two floors of an office building in northern Sweden. The indoor air humidity (normally 10-20% RH) was raised to 23-24% RH, one floor at a time, using steam humidifiers. Questionnaires...

  20. In situ aerosol characterization at Cape Verde. Part 2: Parametrization of relative humidity- and wavelength-dependent aerosol optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Schladitz, Alexander; Muller, Thomas; Nordmann, Stephan; Tesche, Matthias; Wiedensohler, Alfred (Leibniz Institute for Tropospheric Research (IfT), Leipzig (Germany)), e-mail: alexander.schladitz@tropos.de; Gross, Silke; Freudenthaler, Volker; Gasteiger, Josef (Meteorological Institute, Ludwig-Maximilians-Universitaet, Munich (Germany))

    2011-09-15

    An observation-based numerical study of humidity-dependent aerosol optical properties of mixed marine and Saharan mineral dust aerosol is presented. An aerosol model was developed based on measured optical and microphysical properties to describe the marine and Saharan dust aerosol at Cape Verde. A wavelength-dependent optical equivalent imaginary part of the refractive index and a scattering non-sphericity factor for Saharan dust were derived. Simulations of humidity effects on optical properties by the aerosol model were validated with relative measurements of the extinction coefficient at ambient conditions. Parametrizations were derived to describe the humidity dependence of the extinction, scattering, and absorption coefficients as well as the asymmetry parameter and single scattering albedo. For wavelengths (300-950 nm) and dry dust volume fractions (0-1), aerosol optical properties as a function of relative humidity (RH = 0-90%) can be calculated from tabulated parameters. For instance, at a wavelength of 550 nm, a volume fraction of 0.5 of dust on the total particle volume (dry conditions) and a RH of 90%, the enhancements for the scattering, extinction and absorption coefficients are 2.55, 2.46 and 1.04, respectively, while the enhancements for the asymmetry parameter and single scattering albedo are 1.11 and 1.04

  1. Insights into the Surface Reactivity of Cermet and Perovskite Electrodes in Oxidizing, Reducing, and Humid Environments.

    Science.gov (United States)

    Paloukis, Fotios; Papazisi, Kalliopi M; Dintzer, Thierry; Papaefthimiou, Vasiliki; Saveleva, Viktoriia A; Balomenou, Stella P; Tsiplakides, Dimitrios; Bournel, Fabrice; Gallet, Jean-Jacques; Zafeiratos, Spyridon

    2017-08-02

    Understanding the surface chemistry of electrode materials under gas environments is important in order to control their performance during electrochemical and catalytic applications. This work compares the surface reactivity of Ni/YSZ and La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , which are commonly used types of electrodes in solid oxide electrochemical devices. In situ synchrotron-based near-ambient pressure photoemission and absorption spectroscopy experiments, assisted by theoretical spectral simulations and combined with microscopy and electrochemical measurements, are used to monitor the effect of the gas atmosphere on the chemical state, the morphology, and the electrical conductivity of the electrodes. It is shown that the surface of both electrode types readjusts fast to the reactive gas atmosphere and their surface composition is notably modified. In the case of Ni/YSZ, this is followed by evident changes in the oxidation state of nickel, while for La 0.75 Sr 0.25 Cr 0.9 Fe 0.1 O 3 , a fine adjustment of the Cr valence and strong Sr segregation is observed. An important difference between the two electrodes is their capacity to maintain adsorbed hydroxyl groups on their surface, which is expected to be critical for the electrocatalytic properties of the materials. The insight gained from the surface analysis may serve as a paradigm for understanding the effect of the gas environment on the electrochemical performance and the electrical conductivity of the electrodes.

  2. Effect of temperature and humidity on post-gel shrinkage, cusp deformation, bond strength and shrinkage stress - Construction of a chamber to simulate the oral environment.

    Science.gov (United States)

    Bicalho, Aline Aredes; de Souza, Silas Júnior Boaventura; de Rosatto, Camila Maria Peres; Tantbirojn, Daranee; Versluis, Antheunis; Soares, Carlos José

    2015-12-01

    Evaluate the effect of environment on post-gel shrinkage (Shr), cuspal strains (CS), microtensile bond strength (μTBS), elastic modulus (E) and shrinkage stress in molars with large class II restorations. Sixty human molars received standardized Class II mesio-oclusal-distal cavity preparations. Restorations were made with two composites (CHA, Charisma Diamond, Heraus Kulzer and IPS Empress Direct, Ivoclar-Vivadent) using three environment conditions (22°C/50% humidity, 37°C/50% humidity and 37°C/90% humidity) simulated in custom developed chamber. Shr was measured using the strain gauge technique (n=10). CS was measured using strain gauges. Half of the teeth (n=5) were used to assess the elastic modulus (E) and Knoop hardness (KHN) at different depths using microhardness indentation. The other half (n=5) was used to measure the μTBS. The composites and environment conditions were simulated in a two-dimensional finite element analysis of a tooth restoration. Polymerization shrinkage was modeled using Shr data. The Shr, CS, μTBS, KHN and E data were statistically analyzed using two-way ANOVA and Tukey test (significance level: 0.05). Both composites had similar Shr, CS, μTBS and shrinkage stress. CHA had higher elastic modulus than IPS. Increasing temperature and humidity significantly increased Shr, CS and shrinkage stress. μTBS were similar for groups with lower humidity, irrespective of temperature, and higher with higher humidity. E and KHN were constant through the depth for CHA. E and KHN values were affected by environment only for IPS, mainly deeper in the cavity. Shrinkage stress at dentin/composite interface had high inverse correlation with μTBS. Shrinkage stress in enamel had high correlation with CS. Increasing temperature and humidity caused higher post-gel shrinkage and cusp deformation with higher shrinkage stresses in the tooth structure and tooth/restoration interface for both composites tested. The chamber developed for simulating the

  3. Study of the relative humidity dependence of aerosol light-scattering in southern Spain

    Directory of Open Access Journals (Sweden)

    Gloria Titos

    2014-09-01

    Full Text Available This investigation focuses on the characterisation of the aerosol particle hygroscopicity. Aerosol particle optical properties were measured at Granada, Spain, during winter and spring seasons in 2013. Measured optical properties included particle light-absorption coefficient (σap and particle light-scattering coefficient (σsp at dry conditions and at relative humidity (RH of 85±10%. The scattering enhancement factor, f(RH=85%, had a mean value of 1.5±0.2 and 1.6±0.3 for winter and spring campaigns, respectively. Cases of high scattering enhancement were more frequent during the spring campaign with 27% of the f(RH=85% values above 1.8, while during the winter campaign only 8% of the data were above 1.8. A Saharan dust event (SDE, which occurred during the spring campaign, was characterised by a predominance of large particles with low hygroscopicity. For the day when the SDE was more intense, a mean daily value of f(RH=85%=1.3±0.2 was calculated. f(RH=85% diurnal cycle showed two minima during the morning and afternoon traffic rush hours due to the increase in non-hygroscopic particles such as black carbon and road dust. This was confirmed by small values of the single-scattering albedo and the scattering Ångstrom exponent. A significant correlation between f(RH=85% and the fraction of particulate organic matter and sulphate was obtained. Finally, the impact of ambient RH in the aerosol radiative forcing was found to be very small due to the low ambient RH. For high RH values, the hygroscopic effect should be taken into account since the aerosol forcing efficiency changed from −13 W/m2 at dry conditions to −17 W/m2 at RH=85%.

  4. Empirical model for estimating dengue incidence using temperature, rainfall, and relative humidity: a 19-year retrospective analysis in East Delhi.

    Science.gov (United States)

    Ramachandran, Vishnampettai G; Roy, Priyamvada; Das, Shukla; Mogha, Narendra Singh; Bansal, Ajay Kumar

    2016-01-01

    Aedes mosquitoes are responsible for transmitting the dengue virus. The mosquito lifecycle is known to be influenced by temperature, rainfall, and relative humidity. This retrospective study was planned to investigate whether climatic factors could be used to predict the occurrence of dengue in East Delhi. The number of monthly dengue cases reported over 19 years was obtained from the laboratory records of our institution. Monthly data of rainfall, temperature, and humidity collected from a local weather station were correlated with the number of monthly reported dengue cases. One-way analysis of variance was used to analyse whether the climatic parameters differed significantly among seasons. Four models were developed using negative binomial generalized linear model analysis. Monthly rainfall, temperature, humidity, were used as independent variables, and the number of dengue cases reported monthly was used as the dependent variable. The first model considered data from the same month, while the other three models involved incorporating data with a lag phase of 1, 2, and 3 months, respectively. The greatest number of cases was reported during the post-monsoon period each year. Temperature, rainfall, and humidity varied significantly across the pre-monsoon, monsoon, and post-monsoon periods. The best correlation between these three climatic factors and dengue occurrence was at a time lag of 2 months. This study found that temperature, rainfall, and relative humidity significantly affected dengue occurrence in East Delhi. This weather-based dengue empirical model can forecast potential outbreaks 2-month in advance, providing an early warning system for intensifying dengue control measures.

  5. Effect of Relative Humidity and CO2 Concentration on the Properties of Carbonated Reactive MgO Cement Based Materials

    Science.gov (United States)

    Bilan, Yaroslav

    Sustainability of modern concrete industry recently has become an important topic of scientific discussion, and consequently there is an effort to study the potential of the emerging new supplementary cementitious materials. This study has a purpose to investigate the effect of reactive magnesia (reactive MgO) as a replacement for general use (GU) Portland Cements and the effect of environmental factors (CO2 concentrations and relative humidity) on accelerated carbonation curing results. The findings of this study revealed that improvement of physical properties is related directly to the increase in CO2 concentrations and inversely to the increase in relative humidity and also depends much on %MgO in the mixture. The conclusions of this study helped to clarify the effect of variable environmental factors and the material replacement range on carbonation of reactive magnesia concrete materials, as well as providing an assessment of the optimal conditions for the effective usage of the material.

  6. Relationships of relative humidity with PM2.5 and PM10 in the Yangtze River Delta, China.

    Science.gov (United States)

    Lou, Cairong; Liu, Hongyu; Li, Yufeng; Peng, Yan; Wang, Juan; Dai, Lingjun

    2017-10-23

    Severe particulate matter (PM, including PM 2.5 and PM 10 ) pollution frequently impacts many cities in the Yangtze River Delta (YRD) in China, which has aroused growing concern. In this study, we examined the associations between relative humidity (RH) and PM pollution using the equal step-size statistical method. Our results revealed that RH had an inverted U-shaped relationship with PM 2.5 concentrations (peaking at RH = 45-70%), and an inverted V-shaped relationship (peaking at RH = 40 ± 5%) with PM 10 , SO 2 , and NO 2 . The trends of polluted-day number significantly changed at RH = 70%. The very-dry (RH humidity (RH = 60-70%) conditions positively affected PM 2.5 and exerted an accumulation effect, while the mid-humidity (RH = 70-80%), high-humidity (RH = 80-90%), and extreme-humidity (RH = 90-100%) conditions played a significant role in reducing particle concentrations. For PM 10 , the accumulation and reduction effects of RH were split at RH = 45%. Moreover, an upward slope in the PM 2.5 /PM 10 ratio indicated that the accumulation effects from increasing RH were more intense on PM 2.5 than on PM 10 , while the opposite was noticed for the reduction effects. Secondary transformations from SO 2 and NO 2 to sulfate and nitrate were mainly responsible for PM 2.5 pollution, and thus, controlling these precursors is effective in mitigating the PM pollution in the YRD, especially during winter. The conclusions in this study will be helpful for regional air-quality management.

  7. Effect of humid-thermal environment on wave dispersion characteristics of single-layered graphene sheets

    Science.gov (United States)

    Ebrahimi, Farzad; Dabbagh, Ali

    2018-04-01

    In the present article, the hygro-thermal wave propagation properties of single-layered graphene sheets (SLGSs) are investigated for the first time employing a nonlocal strain gradient theory. A refined higher-order two-variable plate theory is utilized to derive the kinematic relations of graphene sheets. Here, nonlocal strain gradient theory is used to achieve a more precise analysis of small-scale plates. In the framework of the Hamilton's principle, the final governing equations are developed. Moreover, these obtained equations are deemed to be solved analytically and the wave frequency values are achieved. Some parametric studies are organized to investigate the influence of different variants such as nonlocal parameter, length scale parameter, wave number, temperature gradient and moisture concentration on the wave frequency of graphene sheets.

  8. Seasonal trend analysis and ARIMA modeling of relative humidity and wind speed time series around Yamula Dam

    Science.gov (United States)

    Eymen, Abdurrahman; Köylü, Ümran

    2018-02-01

    Local climate change is determined by analysis of long-term recorded meteorological data. In the statistical analysis of the meteorological data, the Mann-Kendall rank test, which is one of the non-parametrical tests, has been used; on the other hand, for determining the power of the trend, Theil-Sen method has been used on the data obtained from 16 meteorological stations. The stations cover the provinces of Kayseri, Sivas, Yozgat, and Nevşehir in the Central Anatolia region of Turkey. Changes in land-use affect local climate. Dams are structures that cause major changes on the land. Yamula Dam is located 25 km northwest of Kayseri. The dam has huge water body which is approximately 85 km2. The mentioned tests have been used for detecting the presence of any positive or negative trend in meteorological data. The meteorological data in relation to the seasonal average, maximum, and minimum values of the relative humidity and seasonal average wind speed have been organized as time series and the tests have been conducted accordingly. As a result of these tests, the following have been identified: increase was observed in minimum relative humidity values in the spring, summer, and autumn seasons. As for the seasonal average wind speed, decrease was detected for nine stations in all seasons, whereas increase was observed in four stations. After the trend analysis, pre-dam mean relative humidity time series were modeled with Autoregressive Integrated Moving Averages (ARIMA) model which is statistical modeling tool. Post-dam relative humidity values were predicted by ARIMA models.

  9. Role of relative humidity in processing and storage of seeds and assessment of variability in storage behaviour in Brassica spp. and Eruca sativa.

    Science.gov (United States)

    Suma, A; Sreenivasan, Kalyani; Singh, A K; Radhamani, J

    2013-01-01

    The role of relative humidity (RH) while processing and storing seeds of Brassica spp. and Eruca sativa was investigated by creating different levels of relative humidity, namely, 75%, 50%, 32%, and 11% using different saturated salt solutions and 1% RH using concentrated sulphuric acid. The variability in seed storage behaviour of different species of Brassica was also evaluated. The samples were stored at 40 ± 2°C in sealed containers and various physiological parameters were assessed at different intervals up to three months. The seed viability and seedling vigour parameters were considerably reduced in all accessions at high relative humidity irrespective of the species. Storage at intermediate relative humidities caused minimal decline in viability. All the accessions performed better at relative humidity level of 32% maintaining seed moisture content of 3%. On analyzing the variability in storage behaviour, B. rapa and B. juncea were better performers than B. napus and Eruca sativa.

  10. Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines

    DEFF Research Database (Denmark)

    Fratini, Gerardo; Ibrom, Andreas; Arriga, Nicola

    2012-01-01

    It has been formerly recognised that increasing relative humidity in the sampling line of closed-path eddy-covariance systems leads to increasing attenuation of water vapour turbulent fluctuations, resulting in strong latent heat flux losses. This occurrence has been analyzed for very long (50 m...... from eddy-covariance systems featuring short (4 m) and very short (1 m) sampling lines running at the same clover field and show that relative humidity effects persist also for these setups, and should not be neglected. Starting from the work of Ibrom and co-workers, we propose a mixed method...... and correction method proposed here is deemed applicable to closed-path systems featuring a broad range of sampling lines, and indeed applicable also to passive gases as a special case. The methods described in this paper are incorporated, as processing options, in the free and open-source eddy...

  11. A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D∕H ratios

    Directory of Open Access Journals (Sweden)

    O. Rach

    2017-07-01

    Full Text Available Past climatic change can be reconstructed from sedimentary archives by a number of proxies. However, few methods exist to directly estimate hydrological changes and even fewer result in quantitative data, impeding our understanding of the timing, magnitude and mechanisms of hydrological changes. Here we present a novel approach based on δ2H values of sedimentary lipid biomarkers in combination with plant physiological modeling to extract quantitative information on past changes in relative humidity. Our initial application to an annually laminated lacustrine sediment sequence from western Europe deposited during the Younger Dryas cold period revealed relative humidity changes of up to 15 % over sub-centennial timescales, leading to major ecosystem changes, in agreement with palynological data from the region. We show that by combining organic geochemical methods and mechanistic plant physiological models on well characterized lacustrine archives it is possible to extract quantitative ecohydrological parameters from sedimentary lipid biomarker δ2H data.

  12. Environmental degradation of Opalinus Clay with cyclic variations in relative humidity

    Science.gov (United States)

    Wild, Katrin; Walter, Patric; Madonna, Claudio; Amann, Florian

    2016-04-01

    Clay shales are considered as favorable host rocks for nuclear waste repositories due to their low permeability, high sorption capacity and the potential for self-sealing. However, the favorable characteristics of the rock mass may change during tunnel excavation. Excavation is accompanied by stress redistribution and the development of an excavation damage zone. Furthermore, unloading and exposure to atmospheric conditions with a lower relative humidity (RH) causes desaturation of the rock mass close to the tunnel. This leads to shrinkage and the formation of desiccation cracks. During the open drift stage, seasonal atmospheric changes, especially RH variations, may alter the rock mass and influence the long-term crack evolution. This contribution discusses the influence of RH variation on the mechanical behavior of OPA. A series of specimens were exposed to short-term and long-term, stepwise cyclic RH variations between about 60 and 95% at constant temperature. Strains were measured using strain gauges to monitor the volumetric response during RH cycles. After each applied RH cycle, Brazilian tensile strength (BTS) tests were performed to identify whether there is a change in tensile strength due to environmental damage caused by the change in RH. Swelling and shrinkage of the specimens accompanied by irreversible volumetric expansion was observed as a consequence of the exposure to RH cycles. However, the irreversible strain was limited to the direction normal to bedding suggesting that internal damage is restricted along the bedding planes. No significant effect of cyclic RH variations on the BTS of the specimens was observed. The strength parallel to bedding remained constant over several cycles while the strength normal to bedding shows a slightly decreasing trend after 2 cycles. Furthermore, the water retention characteristics of the specimens were not altered significantly during stepwise RH cycling as the evolution of the water content was reversible

  13. Predicting Indian Summer Monsoon onset through variations of surface air temperature and relative humidity

    Science.gov (United States)

    Stolbova, Veronika; Surovyatkina, Elena; Kurths, Jurgen

    2015-04-01

    Indian Summer Monsoon (ISM) rainfall has an enormous effect on Indian agriculture, economy, and, as a consequence, life and prosperity of more than one billion people. Variability of the monsoonal rainfall and its onset have a huge influence on food production, agricultural planning and GDP of the country, which on 22% is determined by agriculture. Consequently, successful forecasting of the ISM onset is a big challenge and large efforts are being put into it. Here, we propose a novel approach for predictability of the ISM onset, based on critical transition theory. The ISM onset is defined as an abrupt transition from sporadious rainfall to spatially organized and temporally sustained rainfall. Taking this into account, we consider the ISM onset as is a critical transition from pre-monsoon to monsoon, which take place in time and also in space. It allows us to suggest that before the onset of ISM on the Indian subcontinent should be areas of critical behavior where indicators of the critical transitions can be detected through an analysis of observational data. First, we identify areas with such critical behavior. Second, we use detected areas as reference points for observation locations for the ISM onset prediction. Third, we derive a precursor for the ISM onset based on the analysis of surface air temperature and relative humidity variations in these reference points. Finally, we demonstrate the performance of this precursor on two observational data sets. The proposed approach allows to determine ISM onset in advance in 67% of all considered years. Our proposed approach is less effective during the anomalous years, which are associated with weak/strong monsoons, e.g. El-Nino, La-Nina or positive Indian Ocean Dipole events. The ISM onset is predicted for 23 out of 27 normal monsoon years (85%) during the past 6 decades. In the anomalous years, we show that time series analysis in both areas during the pre-monsoon period reveals indicators whether the

  14. Effect of areal power density and relative humidity on corrosion resistant container performance

    International Nuclear Information System (INIS)

    Gansemer, J.D.

    1994-10-01

    The impact of the rewetting process on the performance of waste containers at the Yucca Mountain repository is analyzed. This paper explores the impact of the temperature-humidity relationships on pitting corrosion failure of stainless steel containers for different areal power densities (APDs)in the repository. It compares the likely performance of containers in a repository with a low APD, 55 Kw/acre, and a high APD, 110 kW/acre

  15. Population Growth and Development of the Psocid Liposcelis fusciceps (Psocoptera: Liposcelididae) at Constant Temperatures and Relative Humidities.

    Science.gov (United States)

    Gautam, S G; Opit, G P; Shakya, K

    2016-02-01

    We investigated the effects of seven temperatures (22.5, 25.0, 27.5, 30.0, 32.5, 35.0, and 37.5°C) and four relative humidities (43, 55, 63, and 75%) on population growth and development of the psocid Liposcelis fusciceps Badonnel (Psocoptera: Liposcelididae). Results demonstrated that L. fusciceps did not survive at 43% RH, at all temperatures tested. At 55% RH, L. fusciceps did not survive at the highest three temperatures and no psocids survived at 37.5°C and 63% RH. The highest population growth was recorded at 30.0°C and 75% RH where populations increased 16-fold from an initial population of five females. L. fusciceps males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 28, 70, and 2%, respectively. Female L. fusciceps have two to five instars, and the percentages of females with two, three, four, and five instars were 2, 33, 63, and 2%, respectively. The total developmental time for males was shorter than females. We developed temperature-dependent development equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages. Based on 30-d population growth, L. fusciceps can survive and multiply at a relative humidity of 55% at 22.5-30.0°C, but does better at 27.5-32.5°C and a higher relative humidity of 75%. Relative humidities of ≤ 63% and temperatures of ≥ 32.5°C are detrimental to L. fusciceps. These data provide a better understanding of L. fusciceps population dynamics and can be used to develop effective management strategies for this psocid. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. A Note on the Spatio Temporal Variations in the Temperature and Relative Humidity over Akure, Ondo State, Nigeria

    Science.gov (United States)

    Eludoyin, A. O.; Akinbode, O. M.; Archibong, E. O.

    2007-07-01

    This study was carried out in one of the Administrative State Capitals in the southwestern part of Nigeria. Its aim is to serve as a baseline data for highlighting the effect of spatial distribution of settlements, population, and socioeconomic activities on urban air temperature and relative humidity. The main objective of the study is to assess the impact of urban growth on the microclimate of the administrative city. Temperature and relative humidity data from 1992 to 2001 were obtained from the three existing meteorological stations in Akure, the Administrative Capital of Ondo State, Nigeria, namely the Federal Ministry of Aviation, Akure Airport station (FMA), Federal University of Technology, Akure (FUTA) and the Federal School of Agriculture (SOA). Air temperature and relative humidity measurements along primary roads and in the built up areas were obtained from seventeen stations, using sling psychrometer. The data were subsequently analysed for spatial and temporal variations. The results obtained indicated that while the maximum, average and minimum temperatures showed significant annual variations, the spatial variations among the existing meteorological stations were not significant. The city is characterized by increasing annual mean temperatures whose maximum was significantly higher than that of Ondo town — another important town within the state. The annual mean temperatures ranged between 26.2°C and 30.4°C. Minimum and maximum temperatures varied from 12.3°C to 26°C and 22.5°C to 39.6°C, respectively while the relative humidity ranged between 27.5% and 98.2%. Urban `heat island' intensity was exhibited around central business district of the Oba market. 2007 American Institute of Physics

  17. A complete parameterisation of the relative humidity and wavelength dependence of the refractive index of hygroscopic inorganic aerosol particles

    Directory of Open Access Journals (Sweden)

    M. I. Cotterell

    2017-08-01

    Full Text Available Calculations of aerosol radiative forcing require knowledge of wavelength-dependent aerosol optical properties, such as single-scattering albedo. These aerosol optical properties can be calculated using Mie theory from knowledge of the key microphysical properties of particle size and refractive index, assuming that atmospheric particles are well-approximated to be spherical and homogeneous. We provide refractive index determinations for aqueous aerosol particles containing the key atmospherically relevant inorganic solutes of NaCl, NaNO3, (NH42SO4, NH4HSO4 and Na2SO4, reporting the refractive index variation with both wavelength (400–650 nm and relative humidity (from 100 % to the efflorescence value of the salt. The accurate and precise retrieval of refractive index is performed using single-particle cavity ring-down spectroscopy. This approach involves probing a single aerosol particle confined in a Bessel laser beam optical trap through a combination of extinction measurements using cavity ring-down spectroscopy and elastic light-scattering measurements. Further, we assess the accuracy of these refractive index measurements, comparing our data with previously reported data sets from different measurement techniques but at a single wavelength. Finally, we provide a Cauchy dispersion model that parameterises refractive index measurements in terms of both wavelength and relative humidity. Our parameterisations should provide useful information to researchers requiring an accurate and comprehensive treatment of the wavelength and relative humidity dependence of refractive index for the inorganic component of atmospheric aerosol.

  18. Microbes at Surface-Air Interfaces: The Metabolic Harnessing of Relative Humidity, Surface Hygroscopicity, and Oligotrophy for Resilience

    Science.gov (United States)

    Stone, Wendy; Kroukamp, Otini; Korber, Darren R.; McKelvie, Jennifer; Wolfaardt, Gideon M.

    2016-01-01

    The human environment is predominantly not aqueous, and microbes are ubiquitous at the surface-air interfaces with which we interact. Yet microbial studies at surface-air interfaces are largely survival-oriented, whilst microbial metabolism has overwhelmingly been investigated from the perspective of liquid saturation. This study explored microbial survival and metabolism under desiccation, particularly the influence of relative humidity (RH), surface hygroscopicity, and nutrient availability on the interchange between these two phenomena. The combination of a hygroscopic matrix (i.e., clay or 4,000 MW polyethylene glycol) and high RH resulted in persistent measurable microbial metabolism during desiccation. In contrast, no microbial metabolism was detected at (a) hygroscopic interfaces at low RH, and (b) less hygroscopic interfaces (i.e., sand and plastic/glass) at high or low RH. Cell survival was conversely inhibited at high RH and promoted at low RH, irrespective of surface hygroscopicity. Based on this demonstration of metabolic persistence and survival inhibition at high RH, it was proposed that biofilm metabolic rates might inversely influence whole-biofilm resilience, with ‘resilience’ defined in this study as a biofilm’s capacity to recover from desiccation. The concept of whole-biofilm resilience being promoted by oligotrophy was supported in desiccation-tolerant Arthrobacter spp. biofilms, but not in desiccation-sensitive Pseudomonas aeruginosa biofilms. The ability of microbes to interact with surfaces to harness water vapor during desiccation was demonstrated, and potentially to harness oligotrophy (the most ubiquitous natural condition facing microbes) for adaptation to desiccation. PMID:27746774

  19. Influence of relative humidity in the preservation of irradiated avocados. Part of a coordinated programme on insect disinfestation of food and agricultural products by irradiation

    International Nuclear Information System (INIS)

    Karmelic, V.J.

    1985-02-01

    Avocados were irradiated with gamma rays (Cs-137) and subjected to thermal treatment. Relative humidity (RH) is an important factor in this preservation; the higher the RH the longer the shelf-life. PVC was used to maintain the humidity of the fruits

  20. Long-term Effects of Relative Humidity on Properties of Microwave Hardened Moulding Sand with Sodium Silicate

    Directory of Open Access Journals (Sweden)

    Stachowicz M.

    2017-09-01

    Full Text Available Moulding sands containing sodium silicate (water-glass belong to the group of porous mixture with low resistance to increased humidity. Thanks to hydrophilic properties of hardened or even overheated binder, possible is application of effective methods of hydrous reclamation consisting in its secondary hydration. For the same reason (hydrophilia of the binder, moulds and foundry cores made of high-silica moulding sands with sodium silicate are susceptible to the action of components of atmospheric air, including the contained steam. This paper presents results of a research on the effect of (relative humidity on mechanical and technological properties of microwave-hardened moulding mixtures. Specimens of the moulding sand containing 1.5 wt% of sodium water-glass with module 2.5 were subjected, in a laboratory climatic chamber, to long-term action of steam contained in the chamber atmosphere. Concentration of water in atmospheric air was stabilized for 28 days (672 h according to the relative humidity parameter that was ca. 40%, 60% and 80% at constant temperature 20 °C. In three cycles of the examinations, the specimens were taken out from the chamber every 7 days (168 h and their mechanical and technological parameters were determined. It was found on the grounds of laboratory measurements that moulds and cores hardened with microwaves are susceptible to action of atmospheric air and presence of water (as steam intensifies action of the air components on glassy film of sodium silicate. Microwave-hardened moulding sands containing sodium silicate may be stored on a long-term basis in strictly determined atmospheric conditions only, at reduced humidity. In spite of a negative effect of steam contained in the air, the examined moulding mixtures maintain a part of their mechanical and technological properties, so the moulds and foundry cores stored in specified, controlled conditions could be still used in manufacture.

  1. Assurance of MOZAIC/IAGOS relative humidity data quality by evaluating the Capacitive Hygrometer during airborne field studies

    Science.gov (United States)

    Neis, Patrick; Smit, Herman G. J.; Rohs, Susanne; Rolf, Christian; Krämer, Martina; Ebert, Volker; Buchholz, Bernhard; Bundke, Ulrich; Finger, Fanny; Klingebiel, Marcus; Petzold, Andreas

    2015-04-01

    Water vapour is a major parameter in weather prediction and climate research but the interaction between the water vapour in the upper troposphere and lowermost stratosphere (UT/LS) and tropopause dynamics are not well understood. A continuous measurement of upper tropospheric humidity (UTH) is difficult because the abundance of UTH is highly variable on spatial and temporal scales that cannot be resolved, neither by the global radiosondes network nor by satellites. Since 1994, data with high spatial and temporal resolution for relative humidity are provided by the in-situ measurements aboard civil passenger aircraft from the MOZAIC/IAGOS-programme (www.iagos.org). The data set emerging from this long-term observation effort builds the backbone of the ongoing in-situ UTH climatology and trend analyses. In order to assess the validity of the long-term water vapour data and its limitations, an analysis of the humidity data sets of two field campaigns is presented. The validation of applied measurement methods, i.e. the MOZAIC/IAGOS Capacitive Hygrometer, is valued on the basis of the aircraft campaigns CIRRUS-III (2006) and AIRTOSS-ICE (2013), where research-grade water vapour instruments were operated simultaneously to the MOZAIC/IAGOS Capacitive Hygrometers. The performance of the MOZAIC Capacitive Hygrometer (MCH; operated from 1994 to 2014 on MOZAIC aircraft) and the advanced IAGOS Capacitive Hygrometer (ICH; operated since 2011 on IAGOS aircraft) are explored in clear sky, in the vicinity of and inside cirrus clouds as a blind intercomparison to the research-grade water vapour instruments. From these intercomparisons the qualification of the Capacitive Hygrometer for the use in long-term observation programmes is successfully demonstrated and the continuation of high data quality is confirmed for the transition from MCH to ICH. In particular the Capacitive Hygrometer response time to changes in relative humidity could be determined for the full range of

  2. Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment.

    Science.gov (United States)

    Baker, Lindsay B; Ungaro, Corey T; Barnes, Kelly A; Nuccio, Ryan P; Reimel, Adam J; Stofan, John R

    2014-01-01

    Abstract This study compared a field versus reference laboratory technique for extracting (syringe vs. centrifuge) and analyzing sweat [Na(+)] and [K(+)] (compact Horiba B-722 and B-731, HORIBA vs. ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot-humid environment. Sweat samples were collected from seven anatomical sites on 30 athletes during 1-h cycling in a heat chamber (33°C, 67% rh). Ten minutes into exercise, skin was cleaned/dried and two sweat patches were applied per anatomical site. After removal, one patch per site was centrifuged and sweat was analyzed with HORIBA in the heat chamber (CENTRIFUGE HORIBA) versus HPLC (CENTRIFUGE HPLC). Sweat from the second patch per site was extracted using a 5-mL syringe and analyzed with HORIBA in the heat chamber (SYRINGE HORIBA) versus HPLC (SYRINGE HPLC). CENTRIFUGE HORIBA, SYRINGE HPLC, and SYRINGE HORIBA were highly related to CENTRIFUGE HPLC ([Na(+)]: ICC = 0.96, 0.94, and 0.93, respectively; [K(+)]: ICC = 0.87, 0.92, and 0.84, respectively), while mean differences from CENTRIFUGE HPLC were small but usually significant ([Na(+)]: 4.7 ± 7.9 mEql/L, -2.5 ± 9.3 mEq/L, 4.0 ± 10.9 mEq/L (all P CENTRIFUGE HPLC 95% of the time. The field (SYRINGE HORIBA) method of extracting and analyzing sweat from regional absorbent patches may be useful in obtaining sweat [Na(+)] when rapid estimates in a hot-humid field setting are needed.

  3. Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot‐humid environment

    Science.gov (United States)

    Baker, Lindsay B.; Ungaro, Corey T.; Barnes, Kelly A.; Nuccio, Ryan P.; Reimel, Adam J.; Stofan, John R.

    2014-01-01

    Abstract This study compared a field versus reference laboratory technique for extracting (syringe vs. centrifuge) and analyzing sweat [Na+] and [K+] (compact Horiba B‐722 and B‐731, HORIBA vs. ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot‐humid environment. Sweat samples were collected from seven anatomical sites on 30 athletes during 1‐h cycling in a heat chamber (33°C, 67% rh). Ten minutes into exercise, skin was cleaned/dried and two sweat patches were applied per anatomical site. After removal, one patch per site was centrifuged and sweat was analyzed with HORIBA in the heat chamber (CENTRIFUGE HORIBA) versus HPLC (CENTRIFUGE HPLC). Sweat from the second patch per site was extracted using a 5‐mL syringe and analyzed with HORIBA in the heat chamber (SYRINGE HORIBA) versus HPLC (SYRINGE HPLC). CENTRIFUGE HORIBA, SYRINGE HPLC, and SYRINGE HORIBA were highly related to CENTRIFUGE HPLC ([Na+]: ICC = 0.96, 0.94, and 0.93, respectively; [K+]: ICC = 0.87, 0.92, and 0.84, respectively), while mean differences from CENTRIFUGE HPLC were small but usually significant ([Na+]: 4.7 ± 7.9 mEql/L, −2.5 ± 9.3 mEq/L, 4.0 ± 10.9 mEq/L (all P CENTRIFUGE HPLC 95% of the time. The field (SYRINGE HORIBA) method of extracting and analyzing sweat from regional absorbent patches may be useful in obtaining sweat [Na+] when rapid estimates in a hot‐humid field setting are needed. PMID:24793982

  4. Effects of relative humidity on aerosol light scattering in the Arctic

    Directory of Open Access Journals (Sweden)

    P. Zieger

    2010-04-01

    Full Text Available Aerosol particles experience hygroscopic growth in the ambient atmosphere. Their optical properties – especially the aerosol light scattering – are therefore strongly dependent on the ambient relative humidity (RH. In-situ light scattering measurements of long-term observations are usually performed under dry conditions (RH>30–40%. The knowledge of this RH effect is of eminent importance for climate forcing calculations or for the comparison of remote sensing with in-situ measurements. This study combines measurements and model calculations to describe the RH effect on aerosol light scattering for the first time for aerosol particles present in summer and fall in the high Arctic. For this purpose, a field campaign was carried out from July to October 2008 at the Zeppelin station in Ny-Ålesund, Svalbard. The aerosol light scattering coefficient σsp(λ was measured at three distinct wavelengths (λ=450, 550, and 700 nm at dry and at various, predefined RH conditions between 20% and 95% with a recently developed humidified nephelometer (WetNeph and with a second nephelometer measuring at dry conditions with an average RH<10% (DryNeph. In addition, the aerosol size distribution and the aerosol absorption coefficient were measured. The scattering enhancement factor f(RH, λ is the key parameter to describe the RH effect on σsp(λ and is defined as the RH dependent σsp(RH, λ divided by the corresponding dry σsp(RHdry, λ. During our campaign the average f(RH=85%, λ=550 nm was 3.24±0.63 (mean ± standard deviation, and no clear wavelength dependence of f(RH, λ was observed. This means that the ambient scattering coefficients at RH=85% were on average about three times higher than the dry measured in-situ scattering coefficients. The RH dependency of the recorded f(RH, λ can be well described by an empirical one-parameter equation. We used a simplified

  5. Temperature and relative humidity influence the microbial and physicochemical characteristics of Camembert-type cheese ripening.

    Science.gov (United States)

    Leclercq-Perlat, M-N; Sicard, M; Trelea, I C; Picque, D; Corrieu, G

    2012-08-01

    To evaluate the effects of temperature and relative humidity (RH) on microbial and biochemical ripening kinetics, Camembert-type cheeses were prepared from pasteurized milk seeded with Kluyveromyces marxianus, Geotrichum candidum, Penicillium camemberti, and Brevibacterium aurantiacum. Microorganism growth and biochemical changes were studied under different ripening temperatures (8, 12, and 16°C) and RH (88, 92, and 98%). The central point runs (12°C, 92% RH) were both reproducible and repeatable, and for each microbial and biochemical parameter, 2 kinetic descriptors were defined. Temperature had significant effects on the growth of both K. marxianus and G. candidum, whereas RH did not affect it. Regardless of the temperature, at 98% RH the specific growth rate of P. camemberti spores was significantly higher [between 2 (8°C) and 106 times (16°C) higher]. However, at 16°C, the appearance of the rind was no longer suitable because mycelia were damaged. Brevibacterium aurantiacum growth depended on both temperature and RH. At 8°C under 88% RH, its growth was restricted (1.3 × 10(7) cfu/g), whereas at 16°C and 98% RH, its growth was favored, reaching 7.9 × 10(9) cfu/g, but the rind had a dark brown color after d 20. Temperature had a significant effect on carbon substrate consumption rates in the core as well as in the rind. In the rind, when temperature was 16°C rather than 8°C, the lactate consumption rate was approximately 2.9 times higher under 88% RH. Whatever the RH, temperature significantly affected the increase in rind pH (from 4.6 to 7.7 ± 0.2). At 8°C, an increase in rind pH was observed between d 6 and 9, whereas at 16°C, it was between d 2 and 3. Temperature and RH affected the increasing rate of the underrind thickness: at 16°C, half of the cheese thickness appeared ripened on d 14 (wrapping day). However, at 98% RH, the underrind was runny. In conclusion, some descriptors, such as yeast growth and the pH in the rind, depended solely on

  6. Mitigation of aflatoxin contamination in maize kernels is related to the metabolic alternation of reactive oxygen and nitrogen species by relative humidity

    Science.gov (United States)

    Environmental factors have been shown to be linked to exacerbated infection of maize kernels by Aspergillus flavus and subsequent aflatoxin contamination. Kernel resistance to aflatoxin contamination is associated with kernel water content and relative humidity during in vitro assays examining aflat...

  7. Validation and Spatiotemporal Distribution of GEOS-5-Based Planetary Boundary Layer Height and Relative Humidity in China

    Science.gov (United States)

    Si, Yidan; Li, Shenshen; Chen, Liangfu; Yu, Chao; Wang, Zifeng; Wang, Yang; Wang, Hongmei

    2018-04-01

    Few studies have specifically focused on the validation and spatiotemporal distribution of planetary boundary layer height (PBLH) and relative humidity (RH) data in China. In this analysis, continuous PBLH and surface-level RH data simulated from GEOS-5 between 2004 and 2012, were validated against ground-based observations. Overall, the simulated RH was consistent with the statistical data from meteorological stations, with a correlation coefficient of 0.78 and a slope of 0.9. However, the simulated PBLH was underestimated compared to LIDAR data by a factor of approximately two, which was primarily because of poor simulation in late summer and early autumn. We further examined the spatiotemporal distribution characteristics of two factors in four regions—North China, South China, Northwest China, and the Tibetan Plateau. The results showed that the annual PBLH trends in all regions were fairly moderate but sensitive to solar radiation and precipitation, which explains why the PBLH values were ranked in order from largest to smallest as follows: Tibetan Plateau, Northwest China, North China, and South China. Strong seasonal variation of the PBLH exhibited high values in summer and low values in winter, which was also consistent with the turbulent vertical exchange. Not surprisingly, the highest RH in South China and the lowest RH in desert areas of Northwest China (less than 30%). Seasonally, South China exhibited little variation, whereas Northwest China exhibited its highest humidity in winter and lowest humidity in spring, the maximum values in the other regions were obtained from July to September.

  8. The influence of oxygen, partial vacuum, temperature, relative humidity combined with gamma radiation on the mosquito, Culex pipiens complex l. I. Effect of exposure to temperature and relative humidity alone.

    OpenAIRE

    Hafez, Mahmood [محمود حافظ; Abdel-Rahmen, A. M.; Osman, A. Z.; Wakid, A. M.; Hafez, M. K.

    1993-01-01

    The results revealed that a temperature of 10°C was the most effective temperature on pupal mortality of Culex pipiens complex L. followed by 32°C then 20 and 26°C. There was a gradual increase in pupal mortality with increasing the time of exposure to temperatures. The pupal mortality increased with decreasing the relative humidity levels at the same time of exposure. Exposure for short time periods did not affect significantly the pupal mortality. Increasing the exposure time increased m...

  9. The effects of building-related factors on classroom relative humidity among North Carolina schools participating in the 'Free to Breathe, Free to Teach' study.

    Science.gov (United States)

    Angelon-Gaetz, K A; Richardson, D B; Lipton, D M; Marshall, S W; Lamb, B; LoFrese, T

    2015-12-01

    Both high and low indoor relative humidity (RH) directly impact Indoor Air Quality (IAQ), an important school health concern. Prior school studies reported a high prevalence of mold, roaches, and water damage; however, few examined associations between modifiable classroom factors and RH, a quantitative indicator of dampness. We recorded RH longitudinally in 134 North Carolina classrooms (n = 9066 classroom-days) to quantify the relationships between modifiable classroom factors and average daily RH below, within, or above levels recommended to improve school IAQ (30-50% or 30-60% RH). The odds of having high RH (>60%) were 5.8 [95% Confidence Interval (CI): 2.9, 11.3] times higher in classrooms with annual compared to quarterly heating, ventilating, and air-conditioning (HVAC) system maintenance and 2.5 (95% CI: 1.5, 4.2) times higher in classrooms with HVAC economizers compared to those without economizers. Classrooms with direct-expansion split systems compared to chilled water systems had 2.7 (95% CI: 1.7, 4.4) times higher odds of low RH (60%) of those without setbacks. This research suggests actionable decision points for school design and maintenance to prevent high or low classroom RH. This study combines longitudinal measurements of classroom relative humidity with school inspection data from several schools to describe the problem of relative humidity control in schools. Our findings on how maintenance and mechanical factors affect classroom humidity provide suggestions on building operations policies and heating, ventilating, and air-conditioning (HVAC) design considerations that may improve classroom relative humidity control. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. The influence of relative humidity on the dust measurement with the FH 62 I-N [1 m3.h-1

    International Nuclear Information System (INIS)

    Krasenbrink, A.

    1990-01-01

    The influence of relative humidity (rh) can be noticed evidently at continuous dust measurements if humidity increases rapidly up to more than 90%. This work investigated the possibilities to reduce the resulting error of taking up humidity by using two different types of glass fibre filters, the usual GF10 and its hydrophobic version GF10 HY. Compared with the results of the GF10 it could be shown that the GF10 HY takes up only 63% of humidity per time, yielding a concentration peak with an amount of 66% of the GF10 value. The total amount of absorbed humidity in mass units of the dust monitor differed between 30 μg and 50 μg for the GF10, and between 20 μg and 40 μg for the GF10 HY filter. (orig.) [de

  11. Relative effects of temperature, light, and humidity on clinging behavior of metacercariae-infected ants

    DEFF Research Database (Denmark)

    Botnevik, C.F.; Malagocka, Joanna; Jensen, Annette Bruun

    2016-01-01

    The lancet fluke, Dicrocoelium dendriticum, is perhaps the best-known example of parasite manipulation of host behavior, which is manifested by a radically changed behavior that leaves infected ants attached to vegetation at times when transmission to an herbivore host is optimal. Despite...... the publicity surrounding this parasite, curiously little is known about factors inducing and maintaining behavioral changes in its ant intermediate host. This study examined the importance of 3 environmental factors on the clinging behavior of red wood ants, Formica polyctena , infected with D. dendriticum...... . This behavior, hypothesized to involve cramping of the mandibular muscles in a state of tetany, was observed in naturally infected F. polyctena under controlled temperature, light, and humidity conditions. We found that low temperature significantly stimulated and maintained tetany in infected ants while light...

  12. Influence of reinforcement grade and matrix composition on corrosion resistance of cast aluminium matrix composites (A3xx.x/SiCp) in a humid environment

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Viejo, F.; Carboneras, M. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Quimica Universidad Complutense, 28040, Madrid (Spain); Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain); Lopez, M.D. [Escuela Superior de Ciencias Experimentales y Tecnologia, Universidad Rey Juan Carlos, 28931, Mostoles, Madrid (Spain); Merino, S. [Departamento de Tecnologia Industrial, Universidad Alfonso X El Sabio, 28691, Villanueva de la Canada, Madrid (Spain)

    2003-05-01

    A study of the influence of the silicon carbide (SiC{sub p}) proportion and the matrix concentration of four aluminium metal matrix composites (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p) exposed to high relative humid environment was carried out under simulation in a climatic chamber. The matrix of A360/SiC/xxp composites was virtually free of copper while the A380/SiC/xxp matrix contained 3.13-3.45wt% Cu and 1.39-1.44wt% Ni. The kinetics of the corrosion process was studied on the basis of gravimetric tests. The nature of corrosion products was analysed by Scanning Electron Microscopy (SEM) and Low Angle X-Ray Diffraction (XRD) before and after accelerated testing to determine the influence of microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion damage to Al/SiCp composites was low at 80% Relative Humidity (RH) and increased with temperature, SiCp proportion, relative humidity and Cu matrix concentration. The main attack nucleation sites were the interface region between the matrix and the reinforcement particles. The corrosion process was influenced more by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Eine Studie zum Einfluss des Siliziumkarbidanteils (SiCp) und der Zusammensetzung des Grundwerkstoffs von vier Aluminiummatrixverbundwerkstoffen (A360/SiC/10p, A360/SiC/20p, A380/SiC/10p, A380/SiC/20p), die in Umgebungen mit relativ hoher Feuchtigkeit ausgelagert waren, wurde unter simulierten Bedingungen in einer Klimakammer durchgefuehrt. Die Matrix des A360/SiC/xxp-Verbundwerkstoffs war praktisch Kupfer-frei waehrend die A380/SiC/xxp Matrix 3,13-3,45 Gew.-% Cu und 1,39-1,44 Gew.-% Ni enthielt. Die Kinetik des Korrosionsprozesses wurde auf der Basis von gravimetrischen Messungen studiert. Die Beschaffenheit der Korrosionsprodukte wurde mittelt REM-Untersuchungen und

  13. Influence of relative humidity and physical load during storage on dustiness of inorganic nanomaterials: implications for testing and risk assessment

    International Nuclear Information System (INIS)

    Levin, Marcus; Rojas, Elena; Vanhala, Esa; Vippola, Minnamari; Liguori, Biase; Kling, Kirsten I.; Koponen, Ismo K.; Mølhave, Kristian; Tuomi, Timo; Gregurec, Danijela; Moya, Sergio; Jensen, Keld A.

    2015-01-01

    Dustiness testing using a down-scaled EN15051 rotating drum was used to investigate the effects of storage conditions such as relative humidity and physical loading on the dustiness of five inorganic metal oxide nanostructured powder materials. The tests consisted of measurements of gravimetrical respirable dustiness index and particle size distributions. Water uptake of the powders during 7 days of incubation was investigated as an explanatory factor of the changes. Consequences of these varying storage conditions in exposure modelling were tested using the control banding and risk management tool NanoSafer. Drastic material-specific effects on powder respirable dustiness index were observed with the change in TiO 2 from 30 % RH (639 mg/kg) to 50 % RH (1.5 mg/kg). All five tested materials indicate a decreasing dustiness index with relative humidity increasing from 30 to 70 % RH. Test of powder water uptake showed an apparent link with the decreasing dustiness index. Effects of powder compaction appeared more material specific with both increasing and decreasing dustiness indices observed as an effect of compaction. Tests of control banding exposure models using the measured dustiness indices in three different exposure scenarios showed that in two of the tested materials, one 20 % change in RH changed the exposure banding from the lowest level to the highest. The study shows the importance of powder storage conditions prior to tests for classification of material dustiness indices. It also highlights the importance of correct storage information and relative humidity and expansion of the dustiness test conditions specifically, when using dustiness indices as a primary parameter for source strength in exposure assessment

  14. Influence of relative humidity and physical load during storage on dustiness of inorganic nanomaterials: implications for testing and risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Levin, Marcus, E-mail: mle@nrcwe.dk [Technical University of Denmark, Department of Micro and Nanotechnology (Denmark); Rojas, Elena [CIC biomaGUNE (Spain); Vanhala, Esa; Vippola, Minnamari [Finnish Institute of Occupational Health (Finland); Liguori, Biase; Kling, Kirsten I.; Koponen, Ismo K. [National Research Centre for the Working Environment (Denmark); Mølhave, Kristian [Technical University of Denmark, Department of Micro and Nanotechnology (Denmark); Tuomi, Timo [Finnish Institute of Occupational Health (Finland); Gregurec, Danijela; Moya, Sergio [CIC biomaGUNE (Spain); Jensen, Keld A. [National Research Centre for the Working Environment (Denmark)

    2015-08-15

    Dustiness testing using a down-scaled EN15051 rotating drum was used to investigate the effects of storage conditions such as relative humidity and physical loading on the dustiness of five inorganic metal oxide nanostructured powder materials. The tests consisted of measurements of gravimetrical respirable dustiness index and particle size distributions. Water uptake of the powders during 7 days of incubation was investigated as an explanatory factor of the changes. Consequences of these varying storage conditions in exposure modelling were tested using the control banding and risk management tool NanoSafer. Drastic material-specific effects on powder respirable dustiness index were observed with the change in TiO{sub 2} from 30 % RH (639 mg/kg) to 50 % RH (1.5 mg/kg). All five tested materials indicate a decreasing dustiness index with relative humidity increasing from 30 to 70 % RH. Test of powder water uptake showed an apparent link with the decreasing dustiness index. Effects of powder compaction appeared more material specific with both increasing and decreasing dustiness indices observed as an effect of compaction. Tests of control banding exposure models using the measured dustiness indices in three different exposure scenarios showed that in two of the tested materials, one 20 % change in RH changed the exposure banding from the lowest level to the highest. The study shows the importance of powder storage conditions prior to tests for classification of material dustiness indices. It also highlights the importance of correct storage information and relative humidity and expansion of the dustiness test conditions specifically, when using dustiness indices as a primary parameter for source strength in exposure assessment.

  15. Population growth and development of the psocid Liposcelis rufa (Psocoptera: Liposcelididae) at constant temperatures and relative humidities.

    Science.gov (United States)

    Gautam, S G; Opit, G P; Giles, K L

    2010-10-01

    We investigated the effects of eight temperatures (22.5, 25.0, 27.5, 30.0, 32.5, 35.0, 37.5, and 40.0 degrees C) and four relative humidities (43, 55, 63, and 75%) on population growth and development of the psocid Liposcelis rufa Broadhead (Psocoptera: Liposcelididae). L. rufa did not survive at 43% RH, at all temperatures tested; at 55% RH, at the highest four temperatures; and at 63% RH and 40.0 degrees C. The greatest population growth was recorded at 35.0 degrees C and 75% RH (73-fold growth). At 40.0 degrees C, L. rufa populations declined or barely grew. L. rufa males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 31, 54, and 15%, respectively. Female L. rufa have two to five instars, and the percentages of females with two, three, four, and five instars were 2, 44, 42, and 12%, respectively. The life cycle was shorter for males than females. We developed temperature-dependent developmental equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages. The ability of L. rufa to reproduce at a relative humidity of 55% and temperatures of 22.5-30.0 degrees C and at relative humidities of 63-75% and temperatures of 22.5-37.5 degrees C, in addition to being able to survive at 40.0 degrees C, suggests that this species would be expected to have a broader distribution than other Liposcelis species. These data provide a better understanding of L. rufa population dynamics and can be used to help develop effective management strategies for this psocid.

  16. The environment and community relations

    International Nuclear Information System (INIS)

    Odogwu, E.C.

    1991-01-01

    Even though the petroleum industry in Nigeria has become the back bone of the Nigerian economy the relationship with the communities in the oil producing area is not all what it should be. There has been a significant shift in emphasis from the earlier peaceful and cordial relationship to the present more vocal sometimes violent relationship from a few communities who would like to see the operator held responsible for all environmental lapses of the past 50 years of oil operations in Nigeria. As the leading and most visible oil producer, we experience our share of strained relations in proportion to the size and extent of Shell's operations. Social unrest in the oil producing areas can be attributed to the frequent complaint by the communities of gross neglect by the oil producing companies and the Federal Government of Nigeria in the development of their areas. The community's feeling in that the level of compensation from environmental pollution is not sufficient to compensate the damage caused and this affects good community relations. Also, some communities feel that despite the taxes and royalties paid by multinational companies that, most of the petroleum profit from their God-given wealth is being taken away by such multinationals for development elsewhere. This feeling stems from the perceived glaring disparity between developments in the urban and rural areas where oil operations are carried out. This paper is an attempt to examine the social problems associated with oil exploration and production and the related environmental pollution therefrom and proffer suggestions on how such problems can be solved for good community relations

  17. Characterization of volatile organic compound adsorption on multiwall carbon nanotubes under different levels of relative humidity using linear solvation energy relationship

    International Nuclear Information System (INIS)

    Li, Mei-syue; Wu, Siang Chen; Shih, Yang-hsin

    2016-01-01

    Highlights: • LSER equations successfully predicted VOC sorption on MCNT at different humidity. • The five parameters in LSER could be narrowed down to three ones. • Main interaction is dispersion and partly dipolarity as well as hydrogen-bonds. • With increasing RH, it changes to cavity formation and hydrogen-bond basicity. • This approach can facilitate the VOC control design and the fate prediction. - Abstract: Multiwall carbon nanotubes (MWCNTs) have been used as an adsorbent for evaluating the gas/solid partitioning of selected volatile organic compounds (VOCs). In this study, 15 VOCs were probed to determine their gas/solid partitioning coefficient (Log K d ) using inverse gas chromatography at different relative humidity (RH) levels. Interactions between MWCNTs and VOCs were analyzed by regressing the observed Log K d with the linear solvation energy relationship (LSER). The results demonstrate that the MWCNT carbonyl and carboxyl groups provide high adsorption capacity for the VOCs (Log K d 3.72–5.24 g/kg/g/L) because of the π-/n-electron pair interactions and hydrogen-bond acidity. The increasing RH gradually decreased the Log K d and shifted the interactions to dipolarity/polarizability, hydrogen-bond basicity, and cavity formation. The derived LSER equations provided adequate fits of Log K d , which is useful for VOC-removal processes and fate prediction of VOC contaminants by MWCNT adsorption in the environment.

  18. Characterization of volatile organic compound adsorption on multiwall carbon nanotubes under different levels of relative humidity using linear solvation energy relationship

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mei-syue; Wu, Siang Chen; Shih, Yang-hsin, E-mail: yhs@ntu.edu.tw

    2016-09-05

    Highlights: • LSER equations successfully predicted VOC sorption on MCNT at different humidity. • The five parameters in LSER could be narrowed down to three ones. • Main interaction is dispersion and partly dipolarity as well as hydrogen-bonds. • With increasing RH, it changes to cavity formation and hydrogen-bond basicity. • This approach can facilitate the VOC control design and the fate prediction. - Abstract: Multiwall carbon nanotubes (MWCNTs) have been used as an adsorbent for evaluating the gas/solid partitioning of selected volatile organic compounds (VOCs). In this study, 15 VOCs were probed to determine their gas/solid partitioning coefficient (Log K{sub d}) using inverse gas chromatography at different relative humidity (RH) levels. Interactions between MWCNTs and VOCs were analyzed by regressing the observed Log K{sub d} with the linear solvation energy relationship (LSER). The results demonstrate that the MWCNT carbonyl and carboxyl groups provide high adsorption capacity for the VOCs (Log K{sub d} 3.72–5.24 g/kg/g/L) because of the π-/n-electron pair interactions and hydrogen-bond acidity. The increasing RH gradually decreased the Log K{sub d} and shifted the interactions to dipolarity/polarizability, hydrogen-bond basicity, and cavity formation. The derived LSER equations provided adequate fits of Log K{sub d}, which is useful for VOC-removal processes and fate prediction of VOC contaminants by MWCNT adsorption in the environment.

  19. Multiscale Model Simulations of Temperature and Relative Humidity for the License Application of the Proposed Yucca Mountain Repository

    Science.gov (United States)

    Buscheck, T.; Glascoe, L.; Sun, Y.; Gansemer, J.; Lee, K.

    2003-12-01

    For the proposed Yucca Mountain geologic repository for high-level nuclear waste, the planned method of disposal involves the emplacement of cylindrical packages containing the waste inside horizontal tunnels, called emplacement drifts, bored several hundred meters below the ground surface. The emplacement drifts reside in highly fractured, partially saturated volcanic tuff. An important phenomenological consideration for the licensing of the proposed repository at Yucca Mountain is the generation of decay heat by the emplaced waste and the consequences of this decay heat. Changes in temperature will affect the hydrologic and chemical environment at Yucca Mountain. A thermohydrologic-modeling tool is necessary to support the performance assessment of the Engineered Barrier System (EBS) of the proposed repository. This modeling tool must simultaneously account for processes occurring at a scale of a few tens of centimeters around individual waste packages, for processes occurring around the emplacement drifts themselves, and for processes occurring at the multi-kilometer scale of the mountain. Additionally, many other features must be considered including non-isothermal, multiphase-flow in fractured porous rock of variable liquid-phase saturation and thermal radiation and convection in open cavities. The Multiscale Thermohydrologic Model (MSTHM) calculates the following thermohydrologic (TH) variables: temperature, relative humidity, liquid-phase saturation, evaporation rate, air-mass fraction, gas-phase pressure, capillary pressure, and liquid- and gas-phase fluxes. The TH variables are determined as a function of position along each of the emplacement drifts in the repository and as a function of waste-package (WP) type. These variables are determined at various generic locations within the emplacement drifts, including the waste package and drip-shield surfaces and in the invert; they are also determined at various generic locations in the adjoining host rock

  20. The impact of particle size, relative humidity, and sulfur dioxide on iron solubility in simulated atmospheric marine aerosols.

    Science.gov (United States)

    Cartledge, Benton T; Marcotte, Aurelie R; Herckes, Pierre; Anbar, Ariel D; Majestic, Brian J

    2015-06-16

    Iron is a limiting nutrient in about half of the world's oceans, and its most significant source is atmospheric deposition. To understand the pathways of iron solubilization during atmospheric transport, we exposed size segregated simulated marine aerosols to 5 ppm sulfur dioxide at arid (23 ± 1% relative humidity, RH) and marine (98 ± 1% RH) conditions. Relative iron solubility increased as the particle size decreased for goethite and hematite, while for magnetite, the relative solubility was similar for all of the fine size fractions (2.5-0.25 μm) investigated but higher than the coarse size fraction (10-2.5 μm). Goethite and hematite showed increased solubility at arid RH, but no difference (p > 0.05) was observed between the two humidity levels for magnetite. There was no correlation between iron solubility and exposure to SO2 in any mineral for any size fraction. X-ray absorption near edge structure (XANES) measurements showed no change in iron speciation [Fe(II) and Fe(III)] in any minerals following SO2 exposure. SEM-EDS measurements of SO2-exposed goethite revealed small amounts of sulfur uptake on the samples; however, the incorporated sulfur did not affect iron solubility. Our results show that although sulfur is incorporated into particles via gas-phase processes, changes in iron solubility also depend on other species in the aerosol.

  1. A Revised Calibration Function and Results for the Phoenix Mission TECP Relative Humidity Sensor

    Science.gov (United States)

    Zent, Aaron

    2014-01-01

    The original calibration function of the R(sub H) sensor on the Phoenix Thermal and Electrical Conductivity Sensor (TECP) has been revised in order to extend the range of the valid calibration, and to improve accuracy. The original function returned non-physical R(sub H) values at the lowest temperatures. To resolve this, and because the original calibration was performed against a pair of hygrometers that measured frost point (T(sub f)), the revised calibration equation is also cast in terms of frost point. Because of the complexity of maintaining very low temperatures and high R(sub H) in the laboratory, no calibration data exists at T is greater than 203K. However, sensor response during the mission was smooth and continuous down to 181 K. Therefore we have opted to include flight data in the calibration data set; selection was limited to data acquired during periods when the atmosphere is known to have been saturated. T(sub f) remained below 210 K throughout the mission(P is greater than 0.75 Pa). R(sub H), conversely, ranged from 1 to well under 0.01 diurnally, due to approximately 50 K temperature variations. To first order, both vapor pressure and its variance are greater during daylight hours. Variance in overnight humidity is almost entirely explained by temperature, while atmospheric turbulence contributes substantial variance to daytime humidity. Likewise, data gathered with the TECP aloft reflect higher H2O abundances than at the surface, as well as greater variance. There is evidence for saturation of the atmosphere overnight throughout much of the mission. In virtually every overnight observation, once the atmosphere cooled to T(sub f), water vapor begins to decrease, and tracks air temperature. There is no evidence for substantial decreases in water vapor prior to saturation, as expected for adsorptive exchange. Likewise, there is no evidence of local control of vapor by phases such as perchlorate hydrates hydrated minerals. The daytime average H2O

  2. The Environment in International Relations

    Science.gov (United States)

    Young, Oran R.

    2009-11-01

    In this lucid and well-organized text, Kate O'Neill provides a survey of current thinking in the field of international environmental politics. To make her effort manageable, she approaches this task as an analysis of the “politics of global environmental governance” (p. 1). This approach has the effect of orienting the survey toward research on efforts to develop cooperative and lasting solutions to a variety of environmental problems. The downside of this approach is a relative lack of emphasis on various forms of environmental conflict that lead to outcomes such as growth in the number of environmental refugees and the destruction of important ecosystems. But the virtue of the decision to focus on environmental governance is that it provides a coherent and easily understandable framework for the chapters that follow.

  3. Population growth and development of the psocid Liposcelis brunnea (Psocoptera: Liposcelididae) at constant temperatures and relative humidities.

    Science.gov (United States)

    Opit, G P; Throne, J E

    2009-06-01

    We studied the effects of temperature and relative humidity on population growth and development of the psocid Liposcelis brunnea Motschulsky. L. brunnea did not survive at 43% RH, but populations increased from 22.5 to 32.5 degrees C and 55-75% RH. Interestingly, we found population growth was higher at 63% RH than at 75% RH, and the greatest population growth was recorded at 32.5 degrees C and 63% RH. At 35 degrees C, L. brunnea nymphal survivorship was 33%, and populations declined or barely grew. L. brunnea males have two to four nymphal instars, and the percentages of males with two, three, and four instars were 13, 82, and 5%, respectively. Female L. brunnea have three to five instars, and the percentages of females with three, four, and five instars were 18, 78, and 4%, respectively. The life cycle was shorter for males than females. We developed temperature-dependent development equations for male and female eggs, individual nymphal, combined nymphal, and combined immature stages and nymphal survivorship. The ability of L. brunnea to multiply rather rapidly at 55% RH may allow it to thrive under conditions of low relative humidity where other Liposcelis species may not. These data give us a better understanding of L. brunnea population dynamics and can be used to help develop effective management strategies for this psocid.

  4. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

    Science.gov (United States)

    Johnston, James D; Tuttle, Steven C; Nelson, Morgan C; Bradshaw, Rebecca K; Hoybjerg, Taylor G; Johnson, Julene B; Kruman, Bryce A; Orton, Taylor S; Cook, Ryan B; Eggett, Dennis L; Weber, K Scott

    2016-01-01

    Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr) and summer (July-Sept), 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

  5. Evaporative Cooler Use Influences Temporal Indoor Relative Humidity but Not Dust Mite Allergen Levels in Homes in a Semi-Arid Climate.

    Directory of Open Access Journals (Sweden)

    James D Johnston

    Full Text Available Concerns about energy consumption and climate change make residential evaporative coolers a popular alternative to central air conditioning in arid and semi-arid climates. However, evaporative coolers have been shown to significantly increase indoor relative humidity and dust mite allergen levels in some studies, while showing no association in other studies. Improved measurement of temporal fluctuations in indoor relative humidity may help identify factors that promote mite growth in homes in dry climates. Dust samples and continuous indoor relative humidity measurements were collected from homes with central air conditioning and homes with evaporative coolers in Utah. Samples were collected over two seasons, winter/spring (Jan-Apr and summer (July-Sept, 2014. Dust samples were analyzed for Der p 1 and Der f 1 using a two-site monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA analysis. Housing characteristics including age of home, occupant density, and age of mattresses, furniture, and carpeting were also measured. Positive Der p 1 or Der f 1 samples were found in 25.0% of the homes and there was no difference in mean allergen levels by type of air conditioning. Indoor relative humidity was significantly higher in homes with evaporative coolers compared to those with central air conditioning during the summer. Homes with evaporative coolers also spent significantly more time during summer above 55.0% and 65.0% relative humidity compared to central air homes, but not above 75.0%. Findings from this study suggest that increased humidity from evaporative coolers may not be sufficient to exceed the critical equilibrium humidity or maintain humidity excursions for sufficient duration in relatively larger single-family homes in semi-arid climates to support mite growth and reproduction.

  6. Two types of physical inconsistency to avoid with quantile mapping: a case study with relative humidity over North America.

    Science.gov (United States)

    Grenier, P.

    2017-12-01

    Statistical post-processing techniques aim at generating plausible climate scenarios from climate simulations and observation-based reference products. These techniques are generally not physically-based, and consequently they remedy the problem of simulation biases at the risk of generating physical inconsistency (PI). Although this concern is often emphasized, it is rarely addressed quantitatively. Here, PI generated by quantile mapping (QM), a technique widely used in climatological and hydrological applications, is investigated using relative humidity (RH) and its parent variables, namely specific humidity (SH), temperature and pressure. PI is classified into two types: 1) inadequate value for an individual variable (e.g. RH > 100 %), and 2) breaking of an inter-variable relationship. Scenarios built for this study correspond to twelve sites representing a variety of climate types over North America. Data used are an ensemble of ten 3-hourly global (CMIP5) and regional (CORDEX-NAM) simulations, as well as the CFSR reanalysis. PI of type 1 is discussed in terms of frequency of occurrence and amplitude of unphysical cases for RH and SH variables. PI of type 2 is investigated with heuristic proxies designed to directly compare the physical inconsistency problem with the initial bias problem. Finally, recommendations are provided for an appropriate use of QM given the potential to generate physical inconsistency of types 1 and 2.

  7. An improvement of the retrieval of temperature and relative humidity profiles from a combination of active and passive remote sensing

    Science.gov (United States)

    Che, Yunfei; Ma, Shuqing; Xing, Fenghua; Li, Siteng; Dai, Yaru

    2018-03-01

    This paper focuses on an improvement of the retrieval of atmospheric temperature and relative humidity profiles through combining active and passive remote sensing. Ground-based microwave radiometer and millimeter-wavelength cloud radar were used to acquire the observations. Cloud base height and cloud thickness determinations from cloud radar were added into the atmospheric profile retrieval process, and a back-propagation neural network method was used as the retrieval tool. Because a substantial amount of data are required to train a neural network, and as microwave radiometer data are insufficient for this purpose, 8 years of radiosonde data from Beijing were used as the database. The monochromatic radiative transfer model was used to calculate the brightness temperatures in the same channels as the microwave radiometer. Parts of the cloud base heights and cloud thicknesses in the training data set were also estimated using the radiosonde data. The accuracy of the results was analyzed through a comparison with L-band sounding radar data and quantified using the mean bias, root-mean-square error (RMSE), and correlation coefficient. The statistical results showed that an inversion with cloud information was the optimal method. Compared with the inversion profiles without cloud information, the RMSE values after adding cloud information reduced to varying degrees for the vast majority of height layers. These reductions were particularly clear in layers with clouds. The maximum reduction in the RMSE for the temperature profile was 2.2 K, while that for the humidity profile was 16%.

  8. Hydration forces between aligned DNA helices undergoing B to A conformational change: In-situ X-ray fiber diffraction studies in a humidity and temperature controlled environment.

    Science.gov (United States)

    Case, Ryan; Schollmeyer, Hauke; Kohl, Phillip; Sirota, Eric B; Pynn, Roger; Ewert, Kai E; Safinya, Cyrus R; Li, Youli

    2017-12-01

    Hydration forces between DNA molecules in the A- and B-Form were studied using a newly developed technique enabling simultaneous in situ control of temperature and relative humidity. X-ray diffraction data were collected from oriented calf-thymus DNA fibers in the relative humidity range of 98%-70%, during which DNA undergoes the B- to A-form transition. Coexistence of both forms was observed over a finite humidity range at the transition. The change in DNA separation in response to variation in humidity, i.e. change of chemical potential, led to the derivation of a force-distance curve with a characteristic exponential decay constant of∼2Å for both A- and B-DNA. While previous osmotic stress measurements had yielded similar force-decay constants, they were limited to B-DNA with a surface separation (wall-to-wall distance) typically>5Å. The current investigation confirms that the hydration force remains dominant even in the dry A-DNA state and at surface separation down to∼1.5Å, within the first hydration shell. It is shown that the observed chemical potential difference between the A and B states could be attributed to the water layer inside the major and minor grooves of the A-DNA double helices, which can partially interpenetrate each other in the tightly packed A phase. The humidity-controlled X-ray diffraction method described here can be employed to perform direct force measurements on a broad range of biological structures such as membranes and filamentous protein networks. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Evaluation of a portable gas chromatograph with photoionization detector under variations of VOC concentration, temperature, and relative humidity.

    Science.gov (United States)

    Soo, Jhy-Charm; Lee, Eun Gyung; LeBouf, Ryan F; Kashon, Michael L; Chisholm, William; Harper, Martin

    2018-04-01

    The objective of this present study was to evaluate the performance of a portable gas chromatograph-photoionization detector (GC-PID), under various test conditions to determine if it could be used in occupational settings. A mixture of 7 volatile organic compounds (VOCs)-acetone, ethylbenzene, methyl isobutyl ketone, toluene, m-xylene, p-xylene, and o-xylene-was selected because its components are commonly present in paint manufacturing industries. A full-factorial combination of 4 concentration levels (exposure scenarios) of VOC mixtures, 3 different temperatures (25°C, 30°C, and 35°C), and 3 relative humidities (RHs; 25%, 50%, and 75%) was conducted in a full-size controlled environmental chamber. Three repetitions were conducted for each test condition allowing for estimation of accuracy. Time-weighted average exposure data were collected using solid sorbent tubes (Anasorb 747, SKC Inc.) as the reference sampling medium. Calibration curves of Frog-4000 using the dry gases showed R 2 > 0.99 for all analytes except for toluene (R 2 = 0.97). Frog-4000 estimates within a test condition showed good consistency for the performance of repeated measurement. However, there was ∼41-64% reduction in the analysis of polar acetone with 75% RH relative to collection at 25% RH. Although Frog-4000 results correlated well with solid sorbent tubes (r = 0.808-0.993, except for toluene) most of the combinations regardless of analyte did not meet the <25% accuracy criterion recommended by NIOSH. The effect of chromatographic co-elution can be seen with m, p-xylene when the results are compared to the sorbent tube sampling technique with GC-flame ionization detector. The results indicated an effect of humidity on the quantification of the polar compounds that might be attributed to the pre-concentrator placed in the selected GC-PID. Further investigation may resolve the humidity effect on sorbent trap with micro GC pre-concentrator when water vapor is present. Although this

  10. Importance of relative humidity in the oxidative ageing of organic aerosols: case study of the ozonolysis of maleic acid aerosol

    Directory of Open Access Journals (Sweden)

    P. J. Gallimore

    2011-12-01

    Full Text Available Many important atmospheric aerosol processes depend on the chemical composition of the aerosol, e.g. water uptake and particle cloud interactions. Atmospheric ageing processes, such as oxidation reactions, significantly and continuously change the chemical composition of aerosol particles throughout their lifetime. These ageing processes are often poorly understood. In this study we utilize an aerosol flow tube set up and an ultra-high resolution mass spectrometer to explore the effect of relative humidity (RH in the range of <5–90% on the ozonolysis of maleic acid aerosol which is employed as model organic aerosol system. Due to the slow reaction kinetics relatively high ozone concentrations of 160–200 ppm were used to achieve an appreciable degree of oxidation of maleic acid. The effect of oxidative ageing on the hygroscopicity of maleic acid particles is also investigated using an electrodynamic balance and thermodynamic modelling. RH has a profound effect on the oxidation of maleic acid particles. Very little oxidation is observed at RH < 50% and the only observed reaction products are glyoxylic acid and formic acid. In comparison, when RH > 50% there are about 15 oxidation products identified. This increased oxidation was observed even when the particles were exposed to high humidities long after a low RH ozonolysis reaction. This result might have negative implications for the use of water as an extraction solvent for the analysis of oxidized organic aerosols. These humidity-dependent differences in the composition of the ozonolyzed aerosol demonstrate that water is both a key reactant in the oxidation scheme and a determinant of particle phase and hence diffusivity. The measured chemical composition of the processed aerosol is used to model the hygroscopic growth, which compares favourably with water uptake results from the electrodynamic balance measurements. A reaction mechanism is presented which takes into account the RH dependent

  11. Role of relative humidity in controlling rate of aflatoxin contamination in certain medicinal herbs under prolonged storage

    International Nuclear Information System (INIS)

    Elbazza, Z.E.; Mahmoud, M.I.; Roushdy, H.M.; Farrag, H.A.; Tablawy, S.Y.E.I.

    1995-01-01

    The effect of water activity on growth of aspergillus flavus test strain and aflatoxin production was studied in sabouraoud's yeast broth regulated with glycerol. Aflatoxin production increased with increasing the a w . The minimal a w was 0.92 for fungal growth and aflatoxins production. Growth of A.flavus test strain and aflatoxin production at 26+- I o and two relative humidities of 85% and 92.9% along four months incubation period on caraway, khlla, shih balady and wild chamomile samples were investigated. At 92.9% Rh, growth of A.flavus on caraway and khella samples was noticed after 20 days of incubation and increased with time incubation and increased with time. Aflatoxin production was detected after 30 days and decreased with prolonged incubation. Fungal growth and aflatoxin production were not observed on shih balady and wild chamomile samples at 92.9% Rh, and on the for studied herbs at 85%, Rh. 3 tabs

  12. Influence of relative humidity and physical load during storage on dustiness of inorganic nanomaterials: implications for testing and risk assessment

    DEFF Research Database (Denmark)

    Levin, Marcus; Rojas, Elena; Vanhala, Esa

    2015-01-01

    water uptake showed an apparent link with the decreasing dustiness index. Effects of powder compaction appeared more material specific with both increasing and decreasing dustiness indices observed as an effect of compaction. Tests of control banding exposure models using the measured dustiness indices......Dustiness testing using a down-scaled EN15051 rotating drum was used to investigate the effects of storage conditions such as relative humidity and physical loading on the dustiness of five inorganic metal oxide nanostructured powder materials. The tests consisted of measurements of gravimetrical...... respirable dustiness index and particle size distributions. Water uptake of the powders during 7 days of incubation was investigated as an explanatory factor of the changes. Consequences of these varying storage conditions in exposure modelling were tested using the control banding and risk management tool...

  13. Lead Research and Development Activity for DOE's High Temperature, Low Relative Humidity Membrane Program (Topic 2)

    Energy Technology Data Exchange (ETDEWEB)

    James Fenton, PhD; Darlene Slattery, PhD; Nahid Mohajeri, PhD

    2012-09-05

    The Department of Energy’s High Temperature, Low Relative Humidity Membrane Program was begun in 2006 with the Florida Solar Energy Center (FSEC) as the lead organization. During the first three years of the program, FSEC was tasked with developing non-Nafion® proton exchange membranes with improved conductivity for fuel cells. Additionally, FSEC was responsible for developing protocols for the measurement of in-plane conductivity, providing conductivity measurements for the other funded teams, developing a method for through-plane conductivity and organizing and holding semiannual meetings of the High Temperature Membrane Working Group (HTMWG). The FSEC membrane research focused on the development of supported poly[perfluorosulfonic acid] (PFSA) – Teflon membranes and a hydrocarbon membrane, sulfonated poly(ether ether ketone). The fourth generation of the PFSA membrane (designated FSEC-4) came close to, but did not meet, the Go/No-Go milestone of 0.1 S/cm at 50% relative humidity at 120 °C. In-plane conductivity of membranes provided by the funded teams was measured and reported to the teams and DOE. Late in the third year of the program, DOE used this data and other factors to decide upon the teams to continue in the program. The teams that continued provided promising membranes to FSEC for development of membrane electrode assemblies (MEAs) that could be tested in an operating fuel cell. FSEC worked closely with each team to provide customized support. A logic flow chart was developed and discussed before MEA fabrication or any testing began. Of the five teams supported, by the end of the project, membranes from two of the teams were easily manufactured into MEAs and successfully characterized for performance. One of these teams exceeded performance targets, while the other requires further optimization. An additional team developed a membrane that shows great promise for significantly reducing membrane costs and increasing membrane lifetime.

  14. Relative Humidity of 40% Inhibiting the Increase of Pulse Rate, Body Temperature, and Blood Lactic Acid During Exercise

    Directory of Open Access Journals (Sweden)

    Nengah Sandi

    2016-05-01

    Full Text Available Background: Excessive sweating of the body is a reaction to decrease the heat caused by prolonged exercise at high relative humidity (RH. This situation may cause an increase in pulse rate (PR, body temperature (BT, and blood lactic acid (BLA workout. Objective: This study aimed to prove that a RH of 40% better than a RH of 50% and 60% RH in inhibiting the increase of PR, BT, and BLA during exercise. Methods: The study was conducted on 54 samples randomly selected from the IKIP PGRI Bali students. The samples were divided into three groups, and each group was given cycling exercise with a load of 80 Watt for 2 x 30 minutes with rest between sets for five minutes. Group-1 of cycling at 40% of RH, Group-2 at a RH of 50%, and the Group-3 at a RH of 60%. Data PR, BT, and BLA taken before and during exercise. The mean difference between groups before and during exercise were analyzed by One-way Anova and a further test used Least Significant Difference (LSD. Significance used was α = 0.05. Results: The mean of PR during exercise was significantly different between groups with p = 0.045, the mean of BT during exercises was significantly different between groups with p = 0.006, and the mean of BLA during exercises was significantly different between groups with p = 0.005 (p <0.05. Also found that PR, BT, and BLA during exercise at 40% RH was lower than 50% RH and 60% RH (p <0.05. Conclusion: Thus, the RH of 40% was better than RH of 50% and 60 % in inhibiting the increase of PR, BT, and BLA during exercise. Therefore, when practiced in a closed room is expected at 40% relative humidity.

  15. Atomic force microscopy and X-ray photoelectron spectroscopy study of NO2 reactions on CaCO3 (1014) surfaces in humid environments.

    Science.gov (United States)

    Baltrusaitis, Jonas; Grassian, Vicki H

    2012-09-13

    In this study, alternating current (AC) mode atomic force microscopy (AFM) combined with phase imaging and X-ray photoelectron spectroscopy (XPS) were used to investigate the effect of nitrogen dioxide (NO2) adsorption on calcium carbonate (CaCO3) (101̅4) surfaces at 296 K in the presence of relative humidity (RH). At 70% RH, CaCO3 (101̅4) surfaces undergo rapid formation of a metastable amorphous calcium carbonate layer, which in turn serves as a substrate for recrystallization of a nonhydrated calcite phase, presumably vaterite. The adsorption of nitrogen dioxide changes the surface properties of CaCO3 (101̅4) and the mechanism for formation of new phases. In particular, the first calcite nucleation layer serves as a source of material for further island growth; when it is depleted, there is no change in total volume of nitrocalcite, Ca(NO3)2, particles formed whereas the total number of particles decreases. This indicates that these particles are mobile and coalesce. Phase imaging combined with force curve measurements reveals areas of inhomogeneous energy dissipation during the process of water adsorption in relative humidity experiments, as well as during nitrocalcite particle formation. Potential origins of the different energy dissipation modes within the sample are discussed. Finally, XPS analysis confirms that NO2 adsorbs on CaCO3 (101̅4) in the form of nitrate (NO3(-)) regardless of environmental conditions or the pretreatment of the calcite surface at different relative humidity.

  16. The effect of clothing fit and material of women’s Islamic sportswear on physiological and subjective responses during exercise in warm and humid environment

    OpenAIRE

    Wibowo Astrid Wahyu Adventri; Wijayanto Titis; Widyastuti Watri; Herliansyah Muhammad Kusumawan

    2018-01-01

    The purpose of this study was to investigate the effects of clothing fit and material of Islamic sportswear for female on physiological responses and body heat balance during exercise in warm and humid environment. Twelve healthy female students (20.3±0.4 years) exercised wearing four types of women’s Islamic sportswear comprised of two level of clothing fit: loose-fit and tight-fit, and two types of material for sportswear: cotton and polyester on four separate occasions, and in random order...

  17. Formaldehyde Emissions from Urea-Formaldehyde- and no-added-formaldehyde-Bonded particleboard as Influenced by Temperature and Relative Humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Timothy L. Chaffee; Kyle M. Gonner

    2012-01-01

    It is well documented that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF)–type adhesives. This work investigates the effect of temperature and humidity on newer commercial California Air Resources Board (CARB) phase II–compliant particleboard produced with UF-type adhesives. These...

  18. Formaldehyde emissions from ULEF- and NAF-bonded commercial hardwood plywood as influenced by temperature and relative humidity

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Michael J. Birkeland; Kyle M. Gonner

    2010-01-01

    It is well documented in the literature that temperature and humidity can influence formaldehyde emissions from composite panels that are produced using urea-formaldehyde (UF) adhesives. This work investigates the effect of temperature and humidity on newer, ultra-low emitting formaldehyde urea formaldehyde (ULEF-UF) and no-added formaldehyde (NAF) adhesives. A...

  19. Analysis of the system efficiency of an intermediate temperature proton exchange membrane fuel cell at elevated temperature and relative humidity conditions

    International Nuclear Information System (INIS)

    Jeon, Seung Won; Cha, Dowon; Kim, Hyung Soon; Kim, Yongchan

    2016-01-01

    Highlights: • System efficiency of PEMFC is evaluated at elevated temperature and humidity. • Operating parameters are optimized using response surface methodology. • The optimal operating parameters are T = 90.6 °C, RH = 100.0%, and ζ = 2.07. • The power output and system efficiency are 1.28 W and 15.8% at the optimum. • The system efficiency can be effectively improved by increasing relative humidity. - Abstract: Humidification of the membrane is very important in a proton exchange membrane fuel cell (PEMFC), to maintain high ionic conductivity. At an elevated temperature, a large amount of thermal energy is required for humidification because of the exponentially increased saturation vapor pressure. In this study, the system efficiency of a PEMFC was evaluated by considering the heat required for preheating/humidification and compression work. Three-dimensional steady-state simulations were conducted using Fluent 14 to simulate the electrochemical reactions. The operating conditions were optimized using response surface methodology by considering both the fuel cell output and system efficiency. In addition, the effects of operating parameters such as the temperature, relative humidity, and stoichiometric ratio were investigated. The system efficiency can be improved more effectively by increasing relative humidity rather than increasing operating temperature because the ionic conductivity of the membrane was strongly influenced by the relative humidity.

  20. Effects of atmospheric relative humidity on Stratum Corneum structure at the molecular level: ex vivo Raman spectroscopy analysis.

    Science.gov (United States)

    Vyumvuhore, Raoul; Tfayli, Ali; Duplan, Hélène; Delalleau, Alexandre; Manfait, Michel; Baillet-Guffroy, Arlette

    2013-07-21

    Skin hydration plays an important role in the optimal physical properties and physiological functions of the skin. Despite the advancements in the last decade, dry skin remains the most common characteristic of human skin disorders. Thus, it is important to understand the effect of hydration on Stratum Corneum (SC) components. In this respect, our interest consists in correlating the variations of unbound and bound water content in the SC with structural and organizational changes in lipids and proteins using a non-invasive technique: Raman spectroscopy. Raman spectra were acquired on human SC at different relative humidity (RH) levels (4-75%). The content of different types of water, bound and free, was measured using the second derivative and curve fitting of the Raman bands in the range of 3100-3700 cm(-1). Changes in lipidic order were evaluated using νC-C and νC-H. To analyze the effect of RH on the protein structure, we examined in the Amide I region, the Fermi doublet of tyrosine, and the νasymCH3 vibration. The contributions of totally bound water were found not to vary with humidity, while partially bound water varied with three different rates. Unbound water increased greatly when all sites for bound water were saturated. Lipid organization as well as protein deployment was found to be optimal at intermediate RH values (around 60%), which correspond to the maximum of SC water binding capacity. This analysis highlights the relationship between bound water, the SC barrier state and the protein structure and elucidates the optimal conditions. Moreover, our results showed that increased content of unbound water in the SC induces disorder in the structures of lipids and proteins.

  1. Multi-channel fiber optic dew and humidity sensor

    Science.gov (United States)

    Limodehi, Hamid E.; Mozafari, Morteza; Amiri, Hesam; Légaré, François

    2018-03-01

    In this article, we introduce a multi-channel fiber optic dew and humidity sensor which works using a novel method based on relation between surface plasmon resonance (SPR) and water vapor condensation. The proposed sensor can instantly detect moisture or dew formation through its fiber optic channels, separately situated in different places. It enables to simultaneously measure the ambient Relative Humidity (RH) and dew point temperature of several environments with accuracy of 5%.

  2. Study of the association of atmospheric temperature and relative humidity with bulk tank milk somatic cell count in dairy herds using Generalized additive mixed models.

    Science.gov (United States)

    Testa, Francesco; Marano, Giuseppe; Ambrogi, Federico; Boracchi, Patrizia; Casula, Antonio; Biganzoli, Elia; Moroni, Paolo

    2017-10-01

    Elevated bulk tank milk somatic cell count (BMSCC) has a negative impact on milk production, milk quality, and animal health. Seasonal increases in herd level somatic cell count (SCC) are commonly associated with elevated environmental temperature and humidity. The Temperature Humidity Index (THI) has been developed to measure general environmental stress in dairy cattle; however, additional work is needed to determine a specific effect of the heat stress index on herd-level SCC. Generalized Additive Model methods were used for a flexible exploration of the relationships between daily temperature, relative humidity, and bulk milk somatic cell count. The data consist of BMSCC and meteorological recordings collected between March 2009 and October 2011 of 10 dairy farms. The results indicate that, an average increase of 0.16% of BMSCC is expected for an increase of 1°C degree of temperature. A complex relationship was found for relative humidity. For example, increase of 0.099%, 0.037% and 0.020% are expected in correspondence to an increase of relative humidity from 50% to 51%, 80% to 81%; and 90% to 91%, respectively. Using this model, it will be possible to provide evidence-based advice to dairy farmers for the use of THI control charts created on the basis of our statistical model. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The ameliorative effect of ascorbic acid on the oxidative status, live weight and recovery rate in road transport stressed goats in a hot humid tropical environment.

    Science.gov (United States)

    Nwunuji, Tanko Polycarp; Mayowa, Opeyemi Onilude; Yusoff, Sabri Mohd; Bejo, Siti-Khairani; Salisi, Shahrom; Mohd, Effendy Abd Wahid

    2014-05-01

    The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty-four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post-transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity. © 2014 Japanese Society of Animal Science.

  4. Effect of the state of water and relative humidity on ageing of PLA films.

    Science.gov (United States)

    Rocca-Smith, J R; Chau, N; Champion, D; Brachais, C-H; Marcuzzo, E; Sensidoni, A; Piasente, F; Karbowiak, T; Debeaufort, F

    2017-12-01

    Various types of food are now commercialized in packaging materials based on poly(lactic acid) (PLA) due to its eco-friendly nature. However, one of the main limitations related to PLA is its reactivity with water. For food applications, it is of critical importance to better understand the hydrolysis of PLA driven by water molecules either in liquid or in vapour state. This work focuses on the modifications of PLA induced by water when simulating contact with semi-dry foods (a w ≈0.5), high moisture foods (a w ≈1) and liquid foods (a w ≈1). This study undoubtedly shows that both the chemical potential of water and its physical state influence the hydrolytic degradation of PLA films. From a practical point of view, PLA packaging is very well suited for semi-dry foods, but is highly sensitive to high moisture and liquid foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Relation Between Atmospheric Humidity and Temperature Trends for Stratospheric Water

    Science.gov (United States)

    Fueglistaler, S.; Liu, Y. S.; Flannaghan, T. J.; Haynes, P. H.; Dee, D. P.; Read, W. J.; Remsberg, E. E.; Thomason, L. W.; Hurst, D. F.; Lanzante, J. R.; hide

    2013-01-01

    We analyze the relation between atmospheric temperature and water vapor-a fundamental component of the global climate system-for stratospheric water vapor (SWV). We compare measurements of SWV (and methane where available) over the period 1980-2011 from NOAA balloon-borne frostpoint hygrometer (NOAA-FPH), SAGE II, Halogen Occultation Experiment (HALOE), Microwave Limb Sounder (MLS)/Aura, and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) to model predictions based on troposphere-to-stratosphere transport from ERA-Interim, and temperatures from ERA-Interim, Modern Era Retrospective-Analysis (MERRA), Climate Forecast System Reanalysis (CFSR), Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC), HadAT2, and RICHv1.5. All model predictions are dry biased. The interannual anomalies of the model predictions show periods of fairly regular oscillations, alternating with more quiescent periods and a few large-amplitude oscillations. They all agree well (correlation coefficients 0.9 and larger) with observations for higherfrequency variations (periods up to 2-3 years). Differences between SWV observations, and temperature data, respectively, render analysis of the model minus observation residual difficult. However, we find fairly well-defined periods of drifts in the residuals. For the 1980s, model predictions differ most, and only the calculation with ERA-Interim temperatures is roughly within observational uncertainties. All model predictions show a drying relative to HALOE in the 1990s, followed by a moistening in the early 2000s. Drifts to NOAA-FPH are similar (but stronger), whereas no drift is present against SAGE II. As a result, the model calculations have a less pronounced drop in SWV in 2000 than HALOE. From the mid-2000s onward, models and observations agree reasonably, and some differences can be traced to problems in the temperature data. These results indicate that both SWV and temperature data may still suffer

  6. A scaling approach to Budyko's framework and the complementary relationship of evapotranspiration in humid environments: case study of the Amazon River basin

    Science.gov (United States)

    Carmona, A. M.; Poveda, G.; Sivapalan, M.; Vallejo-Bernal, S. M.; Bustamante, E.

    2016-02-01

    This paper studies a 3-D state space representation of Budyko's framework designed to capture the mutual interdependence among long-term mean actual evapotranspiration (E), potential evapotranspiration (Ep) and precipitation (P). For this purpose we use three dimensionless and dependent quantities: Ψ = E ⁄ P, Φ = Ep ⁄ P and Ω = E ⁄ Ep. This 3-D space and its 2-D projections provide an interesting setting to test the physical soundness of Budyko's hypothesis. We demonstrate analytically that Budyko-type equations are unable to capture the physical limit of the relation between Ω and Φ in humid environments, owing to the unfeasibility of Ep ⁄ P = 0 when E ⁄ Ep → 1. Using data from 146 sub-catchments in the Amazon River basin we overcome this inconsistency by proposing a physically consistent power law: Ψ = kΦe, with k = 0.66, and e = 0.83 (R2 = 0.93). This power law is compared with two other Budyko-type equations. Taking into account the goodness of fits and the ability to comply with the physical limits of the 3-D space, our results show that the power law is better suited to model the coupled water and energy balances within the Amazon River basin. Moreover, k is found to be related to the partitioning of energy via evapotranspiration in terms of Ω. This suggests that our power law implicitly incorporates the complementary relationship of evapotranspiration into the Budyko curve, which is a consequence of the dependent nature of the studied variables within our 3-D space. This scaling approach is also consistent with the asymmetrical nature of the complementary relationship of evapotranspiration. Looking for a physical explanation for the parameters k and e, the inter-annual variability of individual catchments is studied. Evidence of space-time symmetry in Amazonia emerges, since both between-catchment and between-year variability follow the same Budyko curves. Finally, signs of co-evolution of catchments are explored by linking spatial

  7. Psychosocial work environment and building related symptoms

    NARCIS (Netherlands)

    Roda, C.; Bluyssen, P.M.; Mandin, C.; Fossati, S.; Carrer, P.; Kluizenaar, Y. de; Mihucz, V.G.; Oliveira Fernandes, E. de; Bartzis, J.

    2015-01-01

    There is growing evidence that the psychosocial work environment may affect health (Marmot et al. 2006). Nevertheless, these factors are still not commonly taken into account in the studies examining the relations between indoor environmental quality and employee’s health and wellbeing. Several

  8. Friction and wear of hydrogenated and hydrogen-free diamond-like carbon films: Relative humidity dependent character

    Science.gov (United States)

    Shi, Jing; Gong, Zhenbin; Wang, Yongfu; Gao, Kaixiong; Zhang, Junyan

    2017-11-01

    In this study, tribological properties of hydrogenated and hydrogen free diamond-like carbon films at various relative humidity (RH) were investigated to understand the friction mechanism in the presence of water molecules. At normal load of 2N, DLC-H film's friction coefficient was 0.06 at RH14% while DLC film's friction coefficient was 0.19 at RH17%. With the increase of RH, their friction coefficient converged to about 0.15. This character remained unaltered when the normal load was 5N. Results show that low friction of DLC-H film at low RH was attributed to the low shear force aroused by graphitic tribofilm at wear care center. However, the high friction of DLC film was mainly endowed by the high adhesive force aroused by σ dangling bonds. At high RH, solid-to-solid contact was isolated by water molecules confined between the counterfaces, where capillary was a dominant factor for friction. In addition to the capillary force, the absence of tribofilm was also accountable. These two factors lead to the level off of friction coefficient for DLC-H and DLC films. Moreover, for both DLC-H and DLC films, tribo-oxidization was proved to be closely related to wear rate with the assist of H2O molecules during sliding.

  9. Effect of temperature and relative-humidity on the development of Liriomyza sativae Blanchard (Diptera: Agromyzidae) in Vigna unguiculata

    International Nuclear Information System (INIS)

    Lima, Tiago C. Costa; Geremias, Leandro D; Parra, Jose R.P.

    2009-01-01

    This research aimed to study the influence of temperature and relative-humidity (RH) on the development of Liriomyza sativae Blanchard during the egg-adult period, in cowpea, to provide essential information for future biological control projects against the pest. An inverse relation was observed between temperature increase in the range from 15 deg C to 32 deg C and development duration. Larval survival was not affected in the temperature range studied, while a high mortality of pupae was observed at 32 deg C (59.9%). RH did not affect the development time of the immature stages, although it influenced their survival. The lower developmental temperature threshold obtained for the egg-adult period was low (7.3 deg C) when compared with other species of Liriomyza, and was rather low for the larval stage (3.4 deg C ). Based on the thermal requirements for L. sativae, it was possible to estimate the occurrence of 24.5 annual generations at a melon producing region in state of Rio Grande do Norte, Brazil. For laboratory rearing aimed at biological control pest programs, the best rearing conditions are 30 deg C and 50% RH for the larval stage and 90% RH for the pupal stage. (author)

  10. [Effect of temperature and relative-humidity on the development of Liriomyza sativae Blanchard (Diptera: Agromyzidae) in Vigna unguiculata].

    Science.gov (United States)

    Lima, Tiago C Costa; Geremias, Leandro D; Parra, José R P

    2009-01-01

    This research aimed to study the influence of temperature and relative-humidity (RH) on the development of Liriomyza sativae Blanchard during the egg-adult period, in cowpea, to provide essential information for future biological control projects against the pest. An inverse relation was observed between temperature increase in the range from 15 degrees Celsius to 32 degrees Celsius and development duration. Larval survival was not affected in the temperature range studied, while a high mortality of pupae was observed at 32 degrees Celsius (59.9%). RH did not affect the development time of the immature stages, although it influenced their survival. The lower developmental temperature threshold obtained for the egg-adult period was low (7.3 degrees Celsius) when compared with other species of Liriomyza, and was rather low for the larval stage (3.4 degrees Celsius). Based on the thermal requirements for L. sativae, it was possible to estimate the occurrence of 24.5 annual generations at a melon producing region in state of Rio Grande do Norte, Brazil. For laboratory rearing aimed at biological control pest programs, the best rearing conditions are 30 degrees Celsius and 50% RH for the larval stage and 90% RH for the pupal stage.

  11. Corrosion behaviour of AZ91D and AM50 magnesium alloys with Nd and Gd additions in humid environments

    Energy Technology Data Exchange (ETDEWEB)

    Arrabal, R., E-mail: raularrabal@quim.ucm.es [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Matykina, E.; Pardo, A.; Merino, M.C. [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain); Paucar, K. [Gabinete de Corrosion, Facultad de Ingenieria Quimica y Textil, Universidad Nacional de Ingenieria, Cod. Postal 25, Lima (Peru); Mohedano, M.; Casajus, P. [Departamento de Ciencia de Materiales, Facultad de Ciencias Quimicas, Universidad Complutense, 28040 Madrid (Spain)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Mg alloys with additions of Nd and Gd were exposed to high humidity atmosphere. Black-Right-Pointing-Pointer The increase of Nd or Gd diminished the effect of micro-galvanic couples. Black-Right-Pointing-Pointer Corrosion resistance of the AM50 alloy improved with the addition of Nd or Gd by 43%. Black-Right-Pointing-Pointer Nd and Gd had no significant effect on the corrosion resistance of the AZ91D alloy. - Abstract: AM50 and AZ91D alloys modified with rare earths (RE) were evaluated under atmospheric conditions. Nd and Gd additions resulted in formation of Al{sub 2}RE and Al-Mn-RE compounds and reduction of the fraction of {beta}-phase. According to surface potential maps, RE-containing intermetallics were more noble than the {beta}-phase, but less than Al-Mn inclusions. As a result, the action of micro-galvanic couples depended on the added amount of RE and the initial alloy microstructure. Nd or Gd additions improved the corrosion resistance of the AM50 alloy by up to 43%, but had no significant effect on the corrosion resistance of the AZ91D alloy.

  12. Characterizing the Suitability of Selected Indigenous Soil Improving Legumes in a Humid Tropical Environment Using Shoot and Root Attributes

    Directory of Open Access Journals (Sweden)

    Anikwe, MAN.

    2003-01-01

    Full Text Available We studied the biomass accumulation, root length, nodulation, and chemical composition of roots and shoot of ten indigenous soil improving legumes in a humid tropical ecosystem with the view to selecting species for soil improvement programmes. Two cultivars of Vigna unguiculata, and one each of Glycine max, Arachis hypogaea, Crotararia ochroleuca, Cajanus cajan, Pueraria phaseoloides, Lablab purpureus, Mucuna pruriens and Vigna subterranea as treatments were planted in 20 kg pots containing soil from an Oxic paleustalf in Nigeria. The pots were arranged in randomized complete block layout with three replications in a greenhouse at IITA Ibadan, Nigeria. Results from the work show that M. pruriens and C. cajan produced the highest quantity of biomass. Root elongation was highest in M. pruriens whereas A. hypogaea produced the most root nodules with native rhizobia. The highest quantity of nodule dry weight was produced by A. hypogaea and P. phaseoloides whereas most of the legumes except G. max and P. phaseoloides had high and statistically comparable N content of between 2.36 and 3.34 mg.kg-1 N. The results show that the legumes have different root and shoot characteristics, which should be taken into consideration when selecting species for soil improvement programmes.

  13. Corrosion behaviour of AZ91D and AM50 magnesium alloys with Nd and Gd additions in humid environments

    International Nuclear Information System (INIS)

    Arrabal, R.; Matykina, E.; Pardo, A.; Merino, M.C.; Paucar, K.; Mohedano, M.; Casajús, P.

    2012-01-01

    Highlights: ► Mg alloys with additions of Nd and Gd were exposed to high humidity atmosphere. ► The increase of Nd or Gd diminished the effect of micro-galvanic couples. ► Corrosion resistance of the AM50 alloy improved with the addition of Nd or Gd by 43%. ► Nd and Gd had no significant effect on the corrosion resistance of the AZ91D alloy. - Abstract: AM50 and AZ91D alloys modified with rare earths (RE) were evaluated under atmospheric conditions. Nd and Gd additions resulted in formation of Al 2 RE and Al–Mn–RE compounds and reduction of the fraction of β-phase. According to surface potential maps, RE-containing intermetallics were more noble than the β-phase, but less than Al–Mn inclusions. As a result, the action of micro-galvanic couples depended on the added amount of RE and the initial alloy microstructure. Nd or Gd additions improved the corrosion resistance of the AM50 alloy by up to 43%, but had no significant effect on the corrosion resistance of the AZ91D alloy.

  14. Humidity Graphs for All Seasons.

    Science.gov (United States)

    Esmael, F.

    1982-01-01

    In a previous article in this journal (Vol. 17, p358, 1979), a wet-bulb depression table was recommended for two simple experiments to determine relative humidity. However, the use of a graph is suggested because it gives the relative humidity directly from the wet and dry bulb readings. (JN)

  15. Humidity requirements in WSCF Laboratories

    International Nuclear Information System (INIS)

    Evans, R.A.

    1994-01-01

    The purpose of this paper is to develop and document a position on Relative Humidity (RH) requirements in the WSCF Laboratories. A current survey of equipment vendors for Organic, Inorganic and Radiochemical laboratories indicate that 25% - 80% relative humidity may meet the environmental requirements for safe operation and protection of all the laboratory equipment

  16. Towards a Model Climatology of Relative Humidity in the Upper Troposphere for Estimation of Contrail and Contrail-Induced Cirrus

    Science.gov (United States)

    Selkirk, Henry B.; Manyin, M.; Ott, L.; Oman, L.; Benson, C.; Pawson, S.; Douglass, A. R.; Stolarski, R. S.

    2011-01-01

    The formation of contrails and contrail cirrus is very sensitive to the relative humidity of the upper troposphere. To reduce uncertainty in an estimate of the radiative impact of aviation-induced cirrus, a model must therefore be able to reproduce the observed background moisture fields with reasonable and quantifiable fidelity. Here we present an upper tropospheric moisture climatology from a 26-year ensemble of simulations using the GEOS CCM. We compare this free-running model's moisture fields to those obtained from the MLS and AIRS satellite instruments, our most comprehensive observational databases for upper tropospheric water vapor. Published comparisons have shown a substantial wet bias in GEOS-5 assimilated fields with respect to MLS water vapor and ice water content. This tendency is clear as well in the GEOS CCM simulations. The GEOS-5 moist physics in the GEOS CCM uses a saturation adjustment that prevents supersaturation, which is unrealistic when compared to in situ moisture observations from MOZAIC aircraft and balloon sondes as we will show. Further, the large-scale satellite datasets also consistently underestimate super-saturation when compared to the in-situ observations. We place these results in the context of estimates of contrail and contrail cirrus frequency.

  17. Analysis of proton exchange membrane fuel cell polarization losses at elevated temperature 120 C and reduced relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hui; Kunz, H. Russell [Department of Chemical Engineering, University of Connecticut, Storrs, CT (United States); Fenton, James M. [Florida Solar Energy Center, University of Central Florida, Cocoa, FL (United States)

    2007-03-01

    Polarization losses of proton exchange membrane (PEM) fuel cells at 120 C and reduced relative humidity (RH) were analyzed. Reduced RH affects membrane and electrode ionic resistance, catalytic activity and oxygen transport. For a cell made of Nafion {sup registered} 112 membrane and electrodes that have 35 wt.% Nafion {sup registered} and 0.3 mg/cm{sup 2} platinum supported on carbon, membrane resistance at 20%RH was 0.407 {omega} cm{sup 2} and electrode resistance 0.203 {omega} cm{sup 2}, significantly higher than 0.092 and 0.041 {omega} cm{sup 2} at 100%RH, respectively. In the kinetically controlled region, 20%RH resulted in 96 mV more cathode activation loss than 100%RH. Compared to 100%, 20%RH also produced significant oxygen transport loss across the ionomer film in the electrode, 105 mV at 600 mA/cm{sup 2}. The significant increase in polarization losses at elevated temperature and reduced RH indicates the extreme importance of designing electrodes for high temperature PEM fuel cells since membrane development has always taken most emphasis. (author)

  18. Ice formation via deposition nucleation on mineral dust and organics: dependence of onset relative humidity on total particulate surface area

    International Nuclear Information System (INIS)

    Kanji, Zamin A; Florea, Octavian; Abbatt, Jonathan P D

    2008-01-01

    We present ice nucleation results for Arizona test dust, kaolinite, montmorillonite, silica, silica coated with a hydrophobic octyl chain, oxalic acid dihydrate, Gascoyne leonardite (a humic material), and Aldrich humic acid (sodium salt). The focus was on deposition mode nucleation below water saturation at 233 K. Particles were deposited onto a hydrophobic cold stage by atomization of a slurry/solution and exposed to a constant partial pressure of water vapor. By lowering the temperature of the stage, the relative humidity with respect to ice (RH i ) was gradually increased until ice nucleation was observed using digital photography. Different numbers of particles were deposited onto the cold stage by varying the atomization solution concentration and deposition time. For the same total particulate surface area, mineral dust particles nucleated ice at lower supersaturations than all other materials. The most hydrophobic materials, i.e. Gascoyne leonardite and octyl silica, were the least active. For our limit of detection of one ice crystal, the ice onset RH i values were dependent on the total surface area of the particulates, indicating that no unique threshold RH i for ice nucleation prevails

  19. Ice nucleation onto Arizona test dust at cirrus temperatures: effect of temperature and aerosol size on onset relative humidity.

    Science.gov (United States)

    Kanji, Z A; Abbatt, J P D

    2010-01-21

    The University of Toronto Continuous Flow Diffusion Chamber (UT-CFDC) was used to study ice formation onto monodisperse Arizona Test Dust (ATD) particles. The onset relative humidity with respect to ice (RH(i)) was measured as a function of temperature in the range 251-223 K for 100 nm ATD particles. It was found that for 0.1% of the particles to freeze, water saturation was required at all temperatures except 223 K where particles activated at RH(i) below water saturation. At this temperature, where deposition mode freezing is occurring, we find that the larger the particle size, the lower the onset RH(i). We also demonstrate that the total number of particles present may influence the onset RH(i) observed. The surface area for ice activation, aerosol size, and temperature must all be considered when reporting onset values of ice formation onto ATD mineral dust particles. In addition, we calculate nucleation rates and contact angles of ice germs with ATD aerosols which indicate that there exists a range of active sites on the surface with different efficiencies for activating ice formation.

  20. Ice formation via deposition nucleation on mineral dust and organics: dependence of onset relative humidity on total particulate surface area

    Energy Technology Data Exchange (ETDEWEB)

    Kanji, Zamin A; Florea, Octavian; Abbatt, Jonathan P D [Department of Chemistry, University of Toronto, 80 St George Street, Toronto, ON, M5S 3H6 (Canada)], E-mail: zkanji@chem.utoronto.ca

    2008-04-15

    We present ice nucleation results for Arizona test dust, kaolinite, montmorillonite, silica, silica coated with a hydrophobic octyl chain, oxalic acid dihydrate, Gascoyne leonardite (a humic material), and Aldrich humic acid (sodium salt). The focus was on deposition mode nucleation below water saturation at 233 K. Particles were deposited onto a hydrophobic cold stage by atomization of a slurry/solution and exposed to a constant partial pressure of water vapor. By lowering the temperature of the stage, the relative humidity with respect to ice (RH{sub i}) was gradually increased until ice nucleation was observed using digital photography. Different numbers of particles were deposited onto the cold stage by varying the atomization solution concentration and deposition time. For the same total particulate surface area, mineral dust particles nucleated ice at lower supersaturations than all other materials. The most hydrophobic materials, i.e. Gascoyne leonardite and octyl silica, were the least active. For our limit of detection of one ice crystal, the ice onset RH{sub i} values were dependent on the total surface area of the particulates, indicating that no unique threshold RH{sub i} for ice nucleation prevails.

  1. Evaluation of a consolidation treatment in dolostones by mean of calcium hydroxide nanoparticles in high relative humidity conditions

    International Nuclear Information System (INIS)

    Gomez-Villalba, L. s.; Lopez-Arce, P.; Zornoza, A.; Alvares de Buergo, M.; Fort, R.

    2011-01-01

    In this article, the results of a treatment applied to dolomitic stones using an isopropyl colloidal solution based on calcium hydroxide nanoparticles with a concentration of 2.0g/l are presented. The consolidation process in the stone has been checked before and after 28 days of exposure to 75% relative humidity. Morphologic and structural studies of the consolidating product confirmed the carbonation process. X ray diffraction, electron microscopy (TEM and ESEM), and electron diffraction carried out on the consolidating product have confirmed the transformation of portlandite phase to calcium carbonate polymorph, calcite, aragonite and vaterite. Petrophysical tests performed on the stone before and after the application of the product have shown the improvement in the physical and hydrical properties due to the increase in the ultrasound velocity and density of the material, and a decrease in the capillarity coefficient and open porosity without significant changes in colour and brightness. The application of the consolidating product in the proposed experimental conditions is a natural method, compatible with the petrological characteristics of the substrate, without secondary damages on the stone, being an effective method to improve the durability of carbonate stones. (Author) 26 refs.

  2. Elevated air movement enhances stomatal sensitivity to abscisic acid in leaves developed at high relative air humidity

    Directory of Open Access Journals (Sweden)

    Dália R.A. Carvalho

    2015-05-01

    Full Text Available High relative air humidity (RH ≥ 85% during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV 24 h per day, during the whole period of leaf development would increase abscisic acid concentration ([ABA] enhancing stomatal functioning. Pot rose ‘Toril’ was grown at moderate (61% or high (92% RH combined with a negligible MOV or with a continuous MOV of 0.92 m s-1. High MOV reduced stomatal pore length and aperture in plants developed at high RH. Moreover, stomatal function improved when high MOV-treated plants were subjected to leaflet desiccation and ABA feeding. Endogenous concentration of ABA and its metabolites in the leaves was reduced by 35% in high RH, but contrary to our hypothesis this concentration was not significantly affected by high MOV. Interestingly, in detached leaflets grown at high RH, high MOV increased stomatal sensitivity to ABA since the amount of exogenous ABA required to decrease the transpiration rate was significantly reduced. This is the first study to show that high MOV increases stomatal functionality in leaves developed at high RH by reducing the stomatal pore length and aperture and enhancing stomatal sensitivity to ABA rather than increasing leaf [ABA].

  3. Enhanced MEA Performance for PEMFCs under Low Relative Humidity and Low Oxygen Content Conditions via Catalyst Functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Le; Yang, Fan; Xie, Jian; Yang, Zhiwei; Kariuki, Nancy N.; Myers, Deborah J.; Peng, Jui-Kun; Wang, Xiaohua; Ahluwalia, Rajesh K.; Yu, Kang; Ferreira, Paulo J.; Bonastre, Alex Martinez; Fongalland, Dash; Sharman, Jonathan

    2017-01-01

    This work demonstrates that functionalizing annealed-Pt/Ketjen black EC300j (a-Pt/KB) and dealloyed-PtNi/Ketjen black EC300j (d-PtNi/KB) catalysts using p-phenyl sulfonic acid can effectively enhance performance in the membrane electrode assemblies (MEAs) of proton exchange membrane fuel cells (PEMFCs). The functionalization increased the size of both Pt and PtNi catalyst particles and resulted in the further leaching of Ni from the PtNi catalyst while promoting the formation of nanoporous PtNi nanoparticles. The size of the SO3H-Pt/KB and SO3H-PtNi/KB carbon-based aggregates decreased dramatically, leading to the formation of catalyst layers with narrower pore size distributions.MEA tests highlighted the benefits of the surface functionalization, in which the cells with SO3H-Pt/KB and SO3H-PtNi/KB cathode catalysts showed superior high current density performance under reduced RH conditions, in comparison with cells containing annealed Pt/KB (a-Pt/KB) and de-alloyed PtNi/KB (d-PtNi/KB) catalysts. The performance improvement was particularly evident when using reactant gases with low relative humidity, indicating that the hydrophilic functional groups on the carbon improved the water retention in the cathode catalyst layer. These results show a new avenue for enhancing catalyst performance for the next generation of catalytic materials for PEMFCs.

  4. INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON GRAIN MOISTURE, GERMINATION AND VIGOUR OF THREE WHEAT CULTIVARS DURING ONE YEAR STORAGE

    Directory of Open Access Journals (Sweden)

    Ivica Strelec

    2010-12-01

    Full Text Available Changes in grain moisture, germination and vigour of three wheat cultivars packed in paper bags and stored for one year under four different conditions of environmental temperature and relative humidity (RH were investigated. During the first ninety days of storage significant reduction in grain moisture content of 4, 2.5 and 0.9 %, respectively, under 40 °C, 25 °C and 4 °C and RH of 45 % occurred. Subsequently grain moisture remained constant until the end of storage. Seeds of examined cultivars lost their germination ability and vigour only under elevated storage temperatures. Germination and vigour loss after one year of storage differed between cultivars being higher for seeds kept under 40°C, RH = 45% (35-85 % and 55-94 %, respectively, than under 25°C, RH = 45 % (10-20 % and 15-22 %, respectively. Obtained data indicate significant influence of storage conditions on moisture content, germination and vigour changes during storage of wheat seeds, as well as varietal dependence of seed viability.

  5. Impact of relative humidity, inoculum carrier and size, and native microbiota on Salmonella ser. Typhimurium survival in baby lettuce.

    Science.gov (United States)

    López-Gálvez, Francisco; Gil, Maria Isabel; Allende, Ana

    2018-04-01

    The effects of relative humidity (RH), fluctuating climate conditions, inoculum size and carrier on the survival of Salmonella enterica serovar Typhimurium on baby lettuce in environmental test chambers were studied. Buffered peptone water (BPW), distilled water (DW), and irrigation water (IW) were compared as inoculum carriers. Additionally, survival of Salmonella in suspensions prepared using filtered and unfiltered IW was assessed. Salmonella Typhimurium survived better on baby lettuce plants at high RH independently of the inoculum size. When lettuce plants were grown under fluctuating environmental conditions, Salmonella survival was similar under both RH conditions. Regarding the inoculum carrier, the inoculated microorganism survived better on lettuce plants when BPW was used as carrier both at high and low RH. Survival rate of Salmonella in IW was affected by the presence of native microbiota. Native microbiota present in IW did not affect survival of Salmonella or the levels of mesophilic bacteria on the baby lettuce leaves. The information obtained in the present study contributes to the knowledge on the effect of environmental conditions on pathogenic bacteria survival on growing edible plants. These results are useful when selecting the methodology to carry out experimental studies on the survival of microbial pathogens under different pre-harvest conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Mapping near-surface air temperature, pressure, relative humidity and wind speed over Mainland China with high spatiotemporal resolution

    Science.gov (United States)

    Li, Tao; Zheng, Xiaogu; Dai, Yongjiu; Yang, Chi; Chen, Zhuoqi; Zhang, Shupeng; Wu, Guocan; Wang, Zhonglei; Huang, Chengcheng; Shen, Yan; Liao, Rongwei

    2014-09-01

    As part of a joint effort to construct an atmospheric forcing dataset for mainland China with high spatiotemporal resolution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km×1 km. The approach comprises two steps: (1) fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; (2) apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over mainland China. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.

  7. Direct Measurement of pH in Individual Particles via Raman Microspectroscopy and Variation in Acidity with Relative Humidity.

    Science.gov (United States)

    Rindelaub, Joel D; Craig, Rebecca L; Nandy, Lucy; Bondy, Amy L; Dutcher, Cari S; Shepson, Paul B; Ault, Andrew P

    2016-02-18

    Atmospheric aerosol acidity is an important characteristic of aqueous particles, which has been linked to the formation of secondary organic aerosol by catalyzing reactions of oxidized organic compounds that have partitioned to the particle phase. However, aerosol acidity is difficult to measure and traditionally estimated using indirect methods or assumptions based on composition. Ongoing disagreements between experiments and thermodynamic models of particle acidity necessitate improved fundamental understanding of pH and ion behavior in high ionic strength atmospheric particles. Herein, Raman microspectroscopy was used to determine the pH of individual particles (H2SO4+MgSO4) based on sulfate and bisulfate concentrations determined from νs(SO4(2-)) and νs(HSO4(-)), the acid dissociation constant, and activity coefficients from extended Debye-Hückel calculations. Shifts in pH and peak positions of νs(SO4(2-)) and νs(HSO4(-)) were observed as a function of relative humidity. These results indicate the potential for direct spectroscopic determination of pH in individual particles and the need to improve fundamental understanding of ion behavior in atmospheric particles.

  8. Investigating the relationship between Aerosol Optical Depth and Precipitation over Southeast Asia with Relative Humidity as an influencing factor.

    Science.gov (United States)

    Ng, Daniel Hui Loong; Li, Ruimin; Raghavan, Srivatsan V; Liong, Shie-Yui

    2017-10-17

    Atmospheric aerosols influence precipitation by changing the earth's energy budget and cloud properties. A number of studies have reported correlations between aerosol properties and precipitation data. Despite previous research, it is still hard to quantify the overall effects that aerosols have on precipitation as multiple influencing factors such as relative humidity (RH) can distort the observed relationship between aerosols and precipitation. Thus, in this study, both satellite-retrieved and reanalysis data were used to investigate the relationship between aerosols and precipitation in the Southeast Asia region from 2001 to 2015, with RH considered as a possible influencing factor. Different analyses in the study indicate that a positive correlation was present between Aerosol Optical Depth (AOD) and precipitation over northern Southeast Asia region during the autumn and the winter seasons, while a negative correlation was identified over the Maritime Continent during the autumn season. Subsequently, a partial correlation analysis revealed that while RH influences the long-term negative correlations between AOD and precipitation, it did not significantly affect the positive correlations seen in the winter season. The result of this study provides additional evidence with respect to the critical role of RH as an influencing factor in AOD-precipitation relationship over Southeast Asia.

  9. Effects of Relative Humidity on Ozone and Secondary Organic Aerosol Formation from the Photooxidation of Benzene and Ethylbenzene

    Science.gov (United States)

    Jia, L.; Xu, Y.

    2012-12-01

    The formation of ozone and secondary organic aerosol from benzene-NOx and ethylbenzene-NOx irradiations was investigated under different levels of relative humidity (RH) in a smog chamber. The results show that the increase in RH can greatly reduce the maximum O3 by the transformation of -NO2 and -ONO2-containing products into the particle phase. In benzene irradiations, the SOA number concentration increases over 26 times as RH rises from ethylbenzene irradiations, ethylglyoxal favors the formation of monohydrate, which limits the RH effects. During evaporating processes, the lost substances have similar structures for both benzene and ethylbenzene. This demonstrates that ethyl-containing substances are very stable and difficult to evaporate. For benzene some of glyoxal hydrates are left to form C-O-C and C=O-containing species like hemiacetal and acetal after evaporation, whereas for ethylbenzene, glyoxal favors cross reactions with ethylglyoxal during the evaporating process. It is concluded that the increase in RH can irreversibly enhance the yields of SOA from both benzene and ethylbenzene.

  10. Membrane electrode assembly with doped polyaniline interlayer for proton exchange membrane fuel cells under low relative humidity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Cindrella, L. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States); Department of Chemistry, National Institute of Technology, Tiruchirappalli, Tamil Nadu 620015 (India); Kannan, A.M. [Fuel Cell Research Lab, Engineering Technology Department, Arizona State University, Mesa, AZ 85212 (United States)

    2009-09-05

    A membrane electrode assembly (MEA) was designed by incorporating an interlayer between the catalyst layer and the gas diffusion layer (GDL) to improve the low relative humidity (RH) performance of proton exchange membrane fuel cells (PEMFCs). On the top of the micro-porous layer of the GDL, a thin layer of doped polyaniline (PANI) was deposited to retain moisture content in order to maintain the electrolyte moist, especially when the fuel cell is working at lower RH conditions, which is typical for automotive applications. The surface morphology and wetting angle characteristics of the GDLs coated with doped PANI samples were examined using FESEM and Goniometer, respectively. The surface modified GDLs fabricated into MEAs were evaluated in single cell PEMFC between 50 and 100% RH conditions using H{sub 2} and O{sub 2} as reactants at ambient pressure. It was observed that the MEA with camphor sulfonic acid doped PANI interlayer showed an excellent fuel cell performance at all RH conditions including that at 50% at 80 C using H{sub 2} and O{sub 2}. (author)

  11. PEM fuel cells operated at 0% relative humidity in the temperature range of 23-120 oC

    International Nuclear Information System (INIS)

    Zhang, Jianlu; Tang, Yanghua; Song, Chaojie; Cheng, Xuan; Zhang, Jiujun; Wang, Haijiang

    2007-01-01

    Operation of a proton exchange membrane (PEM) fuel cell without external humidification (or 0% relative humidity, abbreviated as 0% RH) of the reactant gases is highly desirable, because it can eliminate the gas humidification system and thus decrease the complexity of the PEM fuel cell system and increase the system volume power density (W/l) and weight power density (W/kg). In this investigation, a PEM fuel cell was operated in the temperature range of 23-120 o C, in particular in a high temperature PEM fuel cell operation range of 80-120 o C, with dry reactant gases, and the cell performance was examined according to varying operation parameters. An ac impedance method was used to compare the performance at 0% RH with that at 100% RH; the results suggested that the limited proton transfer process to the Pt catalysts, mainly in the inonomer within the membrane electrode assembly (MEA) could be responsible for the performance drop. It was demonstrated that operating a fuel cell using a commercially available membrane (Nafion (registered) 112) is feasible under certain conditions without external humidification. However, the cell performance at 0% RH decreased with increasing operation temperature and reactant gas flow rate and decreasing operation pressure

  12. Photocatalytic oxidation of indoor toluene: Process risk analysis and influence of relative humidity, photocatalysts, and VUV irradiation

    International Nuclear Information System (INIS)

    Zhao, Weirong; Dai, Jiusong; Liu, Feifei; Bao, Jiaze; Wang, Yan; Yang, Yong; Yang, Yanan; Zhao, Dongye

    2012-01-01

    Concentrations of 13 gaseous intermediates in photocatalytic oxidation (PCO) of toluene in indoor air were determined in real-time by proton transfer reaction mass spectrometry and desorption intensities of 7 adsorbed intermediates on the surface of photocatalysts were detected by temperature‐programmed desorption‐mass spectrometry. Effects of relative humidity (RH), photocatalysts, and vacuum ultraviolet (VUV) irradiation on the distribution and category of the intermediates and health risk influence index (η) were investigated. RH enhances the formation rate of hydroxide radicals, leading to more intermediates with higher oxidation states in gas phase. N doping promotes the separation of photo-generated electrons and holes and enhances PCO activity accordingly. VUV irradiation results in higher mineralization rate and more intermediates with higher oxidation states and lower toxicity e.g. carboxylic acids. Health risk analysis indicates that higher RH, N doping of TiO 2 , and VUV lead to “greener” intermediates and smaller η. Finally, a conceptual diagram was proposed to exhibit the scenario of η varied with extent of mineralization for various toxicities of inlet pollutants. Highlights: ► 13 volatile intermediates in PCO of toluene were determined in real-time by PTR-MS. ► 7 adsorbed intermediates on surface of photocatalyst were determined by TPD-MS. ► Higher RH, N doping of TiO 2 , and VUV irradiation lead to “greener” intermediates. ► Health risk index relies on extent of mineralization and toxicities of inlet VOCs.

  13. Importance of stress-response genes to the survival of airborne Escherichia coli under different levels of relative humidity.

    Science.gov (United States)

    Ng, Tsz Wai; Chan, Wing Lam; Lai, Ka Man

    2017-12-01

    Other than the needs for infection control to investigate the survival and inactivation of airborne bacterial pathogens, there has been a growing interest in exploring bacterial communities in the air and the effect of environmental variables on them. However, the innate biological mechanism influencing the bacterial viability is still unclear. In this study, a mutant-based approach, using Escherichia coli as a model, was used to prove the concept that common stress-response genes are important for airborne survival of bacteria. Mutants with a single gene knockout that are known to respond to general stress (rpoS) and oxidative stress (oxyR, soxR) were selected in the study. Low relative humidity (RH), 30-40% was more detrimental to the bacteria than high RH, >90%. The log reduction of ∆rpoS was always higher than that of the parental strain at all RH levels but the ∆oxyR had a higher log reduction than the parental strain at intermediate RH only. ∆soxR had the same viability compared to the parental strain at all RH levels. The results hint that although different types and levels of stress are produced under different RH conditions, stress-response genes always play a role in the bacterial viability. This study is the first reporting the association between stress-response genes and viability of airborne bacteria.

  14. A Kinetic Model for Predicting the Relative Humidity in Modified Atmosphere Packaging and Its Application in Lentinula edodes Packages

    Directory of Open Access Journals (Sweden)

    Li-xin Lu

    2013-01-01

    Full Text Available Adjusting and controlling the relative humidity (RH inside package is crucial for ensuring the quality of modified atmosphere packaging (MAP of fresh produce. In this paper, an improved kinetic model for predicting the RH in MAP was developed. The model was based on heat exchange and gases mass transport phenomena across the package, gases heat convection inside the package, and mass and heat balances accounting for the respiration and transpiration behavior of fresh produce. Then the model was applied to predict the RH in MAP of fresh Lentinula edodes (one kind of Chinese mushroom. The model equations were solved numerically using Adams-Moulton method to predict the RH in model packages. In general, the model predictions agreed well with the experimental data, except that the model predictions were slightly high in the initial period. The effect of the initial gas composition on the RH in packages was notable. In MAP of lower oxygen and higher carbon dioxide concentrations, the ascending rate of the RH was reduced, and the RH inside packages was saturated slowly during storage. The influence of the initial gas composition on the temperature inside package was not much notable.

  15. Genotype-environment interaction of maternal influence characteristics in Nellore cattle bred in the Brazilian humid tropical regions by reaction norm

    Directory of Open Access Journals (Sweden)

    Jorge Luís Ferreira

    2015-08-01

    Full Text Available Reaction Norm (RN is the study of genotype-environment interaction (GxE that complies with alternative ways of genotypes within different environments. This study was carried out to verify GxE by a reaction norm model of weights at 120 (W120 and 210 (W210 days of age in Nellore cattle raised in the Humid Tropical Regions of Brazil. Environmental gradients were obtained by solutions of contemporary groups which were fitted as co-variables in the random regression model via reaction norms. Mean weight at 120 days of age was 127.97 kg, and environmental gradients ranged between -27 and +26 kg. Average was 185.60 kg at 210 days of age and gradients ranged from -54 to +55 kg. Scale changes in the breeding values and heritability estimates occurred along the gradients for the two weights; the genetic correlations between breeding value breeding values were also similar for both weights. These correlations were high between the close gradients, and low to even negative between extreme environments. Slopes representing the environmental sensitivity were high, with changes of scale and changes in classification of ten bulls with a great numbers of calves for the two traits. When regression slopes of the ten bulls with the highest breeding value breeding values were evaluated, these values were different in W120 from those in W210, perhaps due to the greater influence of maternal effect on W120. These results characterize the influence of GxE on the pre-weaning weights of animals in the humid tropical regions of Brazil. Due to this, it is possible to get greater precision on the predictions of the animals breeding values breeding value. A less biased selection and a greater genetic progress occurred.

  16. Studies on the effect of the relative humidity of the atmosphere on the growth and physiology of rice [Oryza sativa] plants, 10: Effect of ambient humidity on the translocation of assimilated 13C in leaves

    International Nuclear Information System (INIS)

    Hirai, G.; Okumura, T.; Takeuchi, S.; Tanaka, O.; Chujo, H.; Tanaka, N.

    1996-01-01

    13C-labeled CO2 was fed to rice seedlings for 60 min in the light under low (60%) or high (90%) humidity. The amount of 13C assimilated by the leaves under high humidity was much greater than that by the plants under low humidity. The 13C-labeled CO2 was fed to the plants for 60 min at 75% humidity and then the plants were kept at 60 or 90% humidity under illumination. In 10 hours after the end of 13C feeding, the amount of 13C and 13C content increased in the roots of the plants kept under high humidity. On the other hand, they increased in the sixth leaf and the transfer of 13C to the roots was very low in the plants kept under low humidity. These results support our previous observations that dry matter production of the plants grown under high humidity was higher than that of the plants grown under low humidity, that the dry matter increase of roots in the plants grown under high humidity was higher than that of the plants grown under low humidity and that the stress caused by low humidity increased the partition of dry matter to the top of plants

  17. Indoor air humidity, air quality, and health - An overview.

    Science.gov (United States)

    Wolkoff, Peder

    2018-04-01

    There is a long-standing dispute about indoor air humidity and perceived indoor air quality (IAQ) and associated health effects. Complaints about sensory irritation in eyes and upper airways are generally among top-two symptoms together with the perception "dry air" in office environments. This calls for an integrated analysis of indoor air humidity and eye and airway health effects. This overview has reviewed the literature about the effects of extended exposure to low humidity on perceived IAQ, sensory irritation symptoms in eyes and airways, work performance, sleep quality, virus survival, and voice disruption. Elevation of the indoor air humidity may positively impact perceived IAQ, eye symptomatology, and possibly work performance in the office environment; however, mice inhalation studies do not show exacerbation of sensory irritation in the airways by low humidity. Elevated humidified indoor air appears to reduce nasal symptoms in patients suffering from obstructive apnea syndrome, while no clear improvement on voice production has been identified, except for those with vocal fatigue. Both low and high RH, and perhaps even better absolute humidity (water vapor), favors transmission and survival of influenza virus in many studies, but the relationship between temperature, humidity, and the virus and aerosol dynamics is complex, which in the end depends on the individual virus type and its physical/chemical properties. Dry and humid air perception continues to be reported in offices and in residential areas, despite the IAQ parameter "dry air" (or "wet/humid air") is semantically misleading, because a sensory organ for humidity is non-existing in humans. This IAQ parameter appears to reflect different perceptions among other odor, dustiness, and possibly exacerbated by desiccation effect of low air humidity. It is salient to distinguish between indoor air humidity (relative or absolute) near the breathing and ocular zone and phenomena caused by moisture

  18. Interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological variables in broilers grown to 42 day of age

    Science.gov (United States)

    The interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological reactions in broilers grown to 42 day of age were investigated. The experiment consisted of 2 levels (Moderate=21.1, High=26.7 °C) of temperatures and 2 light sour...

  19. Ambient humidity and the skin: the impact of air humidity in healthy and diseased states.

    Science.gov (United States)

    Goad, N; Gawkrodger, D J

    2016-08-01

    Humidity, along with other climatic factors such as temperature and ultraviolet radiation, can have an important impact on the skin. Limited data suggest that external humidity influences the water content of the stratum corneum. An online literature search was conducted through Pub-Med using combinations of the following keywords: skin, skin disease, humidity, dermatoses, dermatitis, eczema, and mist. Publications included in this review were limited to (i) studies in humans or animals, (ii) publications showing relevance to the field of dermatology, (iii) studies published in English and (iv) publications discussing humidity as an independent influence on skin function. Studies examining environmental factors as composite influences on skin health are only included where the impact of humidity on the skin is also explored in isolation of other environmental factors. A formal systematic review was not feasible for this topic due to the heterogeneity of the available research. Epidemiological studies indicated an increase in eczema with low internal (indoors) humidity and an increase in eczema with external high humidity. Other studies suggest that symptoms of dry skin appear with low humidity internal air-conditioned environments. Murine studies determined that low humidity caused a number of changes in the skin, including the impairment of the desquamation process. Studies in humans demonstrated a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness. Intervention with a humidifying mist increased the water content of the stratum corneum. Conversely, there is some evidence that low humidity conditions can actually improve the barrier function of the skin. Ambient relative humidity has an impact on a range of parameters involved in skin health but the literature is inconclusive. Further

  20. Ultrahigh humidity sensitivity of graphene oxide.

    Science.gov (United States)

    Bi, Hengchang; Yin, Kuibo; Xie, Xiao; Ji, Jing; Wan, Shu; Sun, Litao; Terrones, Mauricio; Dresselhaus, Mildred S

    2013-01-01

    Humidity sensors have been extensively used in various fields, and numerous problems are encountered when using humidity sensors, including low sensitivity, long response and recovery times, and narrow humidity detection ranges. Using graphene oxide (G-O) films as humidity sensing materials, we fabricate here a microscale capacitive humidity sensor. Compared with conventional capacitive humidity sensors, the G-O based humidity sensor has a sensitivity of up to 37800% which is more than 10 times higher than that of the best one among conventional sensors at 15%-95% relative humidity. Moreover, our humidity sensor shows a fast response time (less than 1/4 of that of the conventional one) and recovery time (less than 1/2 of that of the conventional one). Therefore, G-O appears to be an ideal material for constructing humidity sensors with ultrahigh sensitivity for widespread applications.

  1. Sistema automatizado para aquisição de dados de umidade relativa do ar Automated system for relative humidity data acquisition

    Directory of Open Access Journals (Sweden)

    Késia O. da Silva

    2007-12-01

    Full Text Available Devido à importância do ambiente na produção animal e vegetal e, portanto, controle ambiental adequado, o trabalho propõe como objetivo a construção de um sistema de aquisição automatizada de dados de umidade relativa do ar, utilizando-se de microcontrolador de dimensões reduzidas e de baixo custo. A calibração do sensor de umidade relativa foi realizada em três etapas de simulação desenvolvidas em laboratório: caixas perfuradas, dessecador sem tampa contendo sílica-gel em seu fundo e psicrometria. As etapas de calibração, utilizando situações naturais e artificiais, bem como as metodologias desenvolvidas, apresentaram resultados que permitem concluir que o sistema pode ser utilizado com segurança no monitoramento dessa variável.Due the importance of the environment in animal and crop production and therefore an appropriate environmental control, the main objective of this work is the construction of an automated system for relative humidity data acquisition, using a controller with reduced dimensions and low cost. Calibration was performed under natural and artificial conditions. The methodology showed results that the system can be used for monitoring this environmental factor.

  2. Magnesium sulfate salts and historic building materials: experimental simulation of limestone flaking by relative humidity cycling and crystallization of salts

    Directory of Open Access Journals (Sweden)

    Pinchin, S.

    2008-06-01

    Full Text Available Magnesium sulfate salts often result from the combination of incompatible construction materials, such as stone or mortar with high magnesium content and sulfates from adjacent mortars or polluted air. When combined with a source of moisture, these materials react to form soluble salts, often leading to significant damage by flaking of the stone, as the magnesium sulfate responds to fluctuating environmental conditions. Several laboratory experiments were performed to reproduce surface flaking on different types of limestone from Spain and the UK to evaluate the effects of humidity cycling on the damage of stone by salt crystallization. The two salt solutions used for the experiments were a single salt of magnesium sulfate and a mixture of magnesium sulfate, calcium sulfate and sodium chloride, a typical salt mixture found in damaged stone at the site of Howden Minster (UK. A climate chamber with precise and programmable temperature and humidity control was used to test the hypothesis that salt damage in the stone can be readily caused by humidity fluctuations. Damage was monitored using Linear Variable Differential Transformer (LVDT, which measure transducers displacement by dimensional change on the order of microns. In addition, Ion Chromatography, Environmental Scanning Electron Microscopy with energy dispersive X-ray spectroscopy (ESEM-EDX and X-ray Diffraction analyses (XRD were also carried out to analyze salt behavior. Damage by flaking took place in two types of magnesian limestone cubes impregnated with the salt mixture, from Cadeby quarry and York Minster, apparently by deliquescent salts of low equilibrium relative humidity (RHeq, while the rest of the samples developed a salt crust over the surface, but no damage was observed in the stone. It is important to verify hypotheses developed from field observations with laboratory experiments. By combining both field and laboratory data, a clearer understanding the different mechanisms of

  3. Differentiation of Volatile Profiles from Stockpiled Almonds at Varying Relative Humidity Levels Using Benchtop and Portable GC-MS.

    Science.gov (United States)

    Beck, John J; Willett, Denis S; Gee, Wai S; Mahoney, Noreen E; Higbee, Bradley S

    2016-12-14

    Contamination by aflatoxin, a toxic metabolite produced by Aspergillus fungi ubiquitous in California almond and pistachio orchards, results in millions of dollars of lost product annually. Current detection of aflatoxin relies on destructive, expensive, and time-intensive laboratory-based methods. To explore an alternative method for the detection of general fungal growth, volatile emission profiles of almonds at varying humidities were sampled using both static SPME and dynamic needle-trap SPE followed by benchtop and portable GC-MS analysis. Despite the portable SPE/GC-MS system detecting fewer volatiles than the benchtop system, both systems resolved humidity treatments and identified potential fungal biomarkers at extremely low water activity levels. This ability to resolve humidity levels suggests that volatile profiles from germinating fungal spores could be used to create an early warning, nondestructive, portable detection system of fungal growth.

  4. Effect of temperature and relative humidity on the development times and survival of Synopsyllus fonquerniei and Xenopsylla cheopis, the flea vectors of plague in Madagascar.

    Science.gov (United States)

    Kreppel, Katharina S; Telfer, Sandra; Rajerison, Minoarisoa; Morse, Andy; Baylis, Matthew

    2016-02-11

    Plague, a zoonosis caused by Yersinia pestis, is found in Asia, the Americas but mainly in Africa, with the island of Madagascar reporting almost one third of human cases worldwide. In the highlands of Madagascar, plague is transmitted predominantly by two flea species which coexist on the island, but differ in their distribution. The endemic flea, Synopsyllus fonquerniei, dominates flea communities on rats caught outdoors, while the cosmopolitan flea, Xenopsylla cheopis, is found mostly on rats caught in houses. Additionally S. fonquerniei seems restricted to areas above 800 m. Climatic constraints on the development of the two main vectors of plague could explain the differences in their distribution and the seasonal changes in their abundance. Here we present the first study on effects of temperature and relative humidity on the immature stages of both vector species. We examined the two species' temperature and humidity requirements under experimental conditions at five different temperatures and two relative humidities. By employing multivariate and survival analysis we established the impact of temperature and relative humidity on development times and survival for both species. Using degree-day analysis we then predicted the average developmental threshold for larvae to reach pupation and for pupae to complete development under each treatment. This analysis was undertaken separately for the two relative humidities and for the two species. Development times and time to death differed significantly, with the endemic S. fonquerniei taking on average 1.79 times longer to complete development and having a shorter time to death than X. cheopis under adverse conditions with high temperature and low humidity. Temperature had a significant effect on the development times of flea larvae and pupae. While humidity did not affect the development times of either species, it did influence the time of death of S. fonquerniei. Using degree-day analysis we estimated an

  5. Long-term perceptions of outdoor thermal environments in an elementary school in a hot-humid climate

    Science.gov (United States)

    Shih, Wen-Mei; Lin, Tzu-Ping; Tan, Ning-Xin; Liu, Mu-Hsien

    2017-09-01

    Previous studies on thermal comfort in school environments have focused more on indoor thermal environments than outdoor ones, thus providing a limited understanding of occupants' long-term thermal perceptions. Taiwan is located in a subtropical region, where it can be stiflingly hot outside in summer. This highlights the need to ensure proper thermal comfort on campus. In the present study, thermal environment parameters were measured and collected in several outdoor spaces of an elementary school in southern Taiwan. In addition, a questionnaire was used to explore occupants' long-term thermal perceptions of these spaces. During summer months, the physiological equivalent temperature (PET) of these outdoor spaces in over 60% of the daytime in summer between 10 a.m. and 4 p.m. was higher than 38 °C PET, indicating high heat stress. The results of occupants' long-term perceptions of the thermal comfort of these spaces suggested that dissatisfaction with thermal comfort was associated more with solar radiation than with wind speed. Finally, this study simulated a campus environment where more trees are planted and compared the thermal comfort indices before and after the simulation. The results indicated that this solution contributed to a decrease in the PET of these environments, thereby alleviating high heat stress. This study can inform the improvement of microclimates and thermal comfort during campus layout planning. Planting trees judiciously across a campus increases outdoor shades and creates outdoor spaces that are more comfortable and adaptable to hot weather conditions, thereby ensuring frequent use of these spaces.

  6. Crystallization of aqueous ammonium sulfate particles internally mixed with soot and kaolinite: crystallization relative humidities and nucleation rates.

    Science.gov (United States)

    Pant, Atul; Parsons, Matthew T; Bertram, Allan K

    2006-07-20

    Using optical microscopy, we investigated the crystallization of aqueous ammonium sulfate droplets containing soot and kaolinite, as well as the crystallization of aqueous ammonium sulfate droplets free of solid material. Our results show that soot did not influence the crystallization RH of aqueous ammonium sulfate particles under our experimental conditions. In contrast, kaolinite increased the crystallization RH of the aqueous ammonium sulfate droplets by approximately 10%. In addition, our results show that the crystallization RH of aqueous ammonium sulfate droplets free of solid material does not depend strongly on particle size. This is consistent with conclusions made previously in the literature, based on comparisons of results from different laboratories. From the crystallization results we determined the homogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate droplets and the heterogeneous nucleation rates of crystalline ammonium sulfate in aqueous ammonium sulfate particles containing kaolinite. Using classical nucleation theory and our experimental data, we determined that the interfacial tension between an ammonium sulfate critical nucleus and an aqueous ammonium sulfate solution is 0.064 +/- 0.003 J m(-2) (in agreement with our previous measurements), and the contact angle between an ammonium sulfate critical nucleus and a kaolinite surface is 59 +/- 2 degrees. On the basis of our results, we argue that soot will not influence the crystallization RH of aqueous ammonium sulfate droplets in the atmosphere, but kaolinite can significantly modify the crystallization RH of atmospheric ammonium sulfate droplets. As an example, the CRH50 (the relative humidity at which 50% of the droplets crystallize) ranges from about 41 to 51% RH when the diameter of the kaolinite inclusion ranges from 0.1 to 5 microm. For comparison, the CRH50 of aqueous ammonium sulfate droplets (0.5 microm diameter) free of solid material is

  7. Kinetics of Heterogeneous Reaction of Sulfur Dioxide on Authentic Mineral Dust: Effects of Relative Humidity and Hydrogen Peroxide.

    Science.gov (United States)

    Huang, Liubin; Zhao, Yue; Li, Huan; Chen, Zhongming

    2015-09-15

    Heterogeneous reaction of SO2 on mineral dust seems to be an important sink for SO2. However, kinetic data about this reaction on authentic mineral dust are scarce and are mainly limited to low relative humidity (RH) conditions. In addition, little is known about the role of hydrogen peroxide (H2O2) in this reaction. Here, we investigated the uptake kinetics of SO2 on three authentic mineral dusts (i.e., Asian mineral dust (AMD), Tengger desert dust (TDD), and Arizona test dust (ATD)) in the absence and presence of H2O2 at different RHs using a filter-based flow reactor, and applied a parameter (effectiveness factor) to the estimation of the effective surface area of particles for the calculation of the corrected uptake coefficient (γc). We found that with increasing RH, the γc decreases on AMD particles, but increases on ATD and TDD particles. This discrepancy is probably due to the different mineralogy compositions and aging extents of these dust samples. Furthermore, the presence of H2O2 can promote the uptake of SO2 on mineral dust at different RHs. The probable explanations are that H2O2 rapidly reacts with SO2 on mineral dust in the presence of adsorbed water, and OH radicals, which can be produced from the heterogeneous decomposition of H2O2 on the mineral dust, immediately react with adsorbed SO2 as well. Our results suggest that the removal of SO2 via the heterogeneous reaction on mineral dust is an important sink for SO2 and has the potential to alter the physicochemical properties (e.g., ice nucleation ability) of mineral dust particles in the atmosphere.

  8. Induction of genetic changes in Saccharomyces cerevisiae by partial drying in air of constant relative humidity and by UV

    International Nuclear Information System (INIS)

    Hieda, K.

    1981-01-01

    It was investigated whether there was a critical degree of dryness for induction of genetic changes by drying. Saccharomyces cerevisiae cells were dried in air of 0.33, 53 and 76% relative humidity (RH). The frequencies of mitotic recombination at ade2, of gene conversion at leu1, and of gene mutation at can1 were measured in X2447, XS1473 and S288C strains, respectively. After the cells had been dried at 0% RH for 4 h the frequencies of the genetic changes at ade2, leu1 and can1 were, respectively, 56, 7 and 3.5 times higher than each spontaneous frequency. Induction rates, defined as the frequencies of the induced genetic changes per unit time (1 h) of drying, were greatly decreased with increase in RH. Partial drying in air of 76% RH up to 4 and 8 h induced no genetic change at ade2 and leu1, respectively. It was concluded, therefore, that drying at a certain RH between 53 and 76% gave the critical degreee of dryness of cells for the induction of the genetic changes. The water contents of cells (g water per g dry material) were 12% at 53% RH and 21% at 76% RH, whereas the water content of native cells was 212%. Removal of a large amount of cellular water had no effect on the induction of the genetic changes. UV sensitivity of partially dried cells of X2447 for the induction of the genetic change at ade2 drastically increased with decrease in RH between 76 and 53%. The drastic change in the UV sensitivity suggested that photochemical reactivity of DNA of chromosome XV, in which the ade2 locus is located, changed between 76 and 53% RH. It seems that the genetic changes were induced only in the low RH region where DNA in vivo had a different photochemical reactivity. (orig.)

  9. A Model for Sclerotinia sclerotiorum Infection and Disease Development in Lettuce, Based on the Effects of Temperature, Relative Humidity and Ascospore Density

    Science.gov (United States)

    Clarkson, John P.; Fawcett, Laura; Anthony, Steven G.; Young, Caroline

    2014-01-01

    The plant pathogen Sclerotinia sclerotiorum can cause serious losses on lettuce crops worldwide and as for most other susceptible crops, control relies on the application of fungicides, which target airborne ascospores. However, the efficacy of this approach depends on accurate timing of these sprays, which could be improved by an understanding of the environmental conditions that are conducive to infection. A mathematical model for S. sclerotiorum infection and disease development on lettuce is presented here for the first time, based on quantifying the effects of temperature, relative humidity (RH) and ascospore density in multiple controlled environment experiments. It was observed that disease can develop on lettuce plants inoculated with dry ascospores in the absence of apparent leaf wetness (required for spore germination). To explain this, the model conceptualises an infection court area containing microsites (in leaf axils and close to the stem base) where conditions are conducive to infection, the size of which is modified by ambient RH. The model indicated that minimum, maximum and optimum temperatures for ascospore germination were 0.0, 29.9 and 21.7°C respectively and that maximum rates of disease development occurred at spore densities >87 spores cm−2. Disease development was much more rapid at 80–100% RH at 20°C, compared to 50–70% RH and resulted in a greater proportion of lettuce plants infected. Disease development was also more rapid at 15–27°C compared to 5–10°C (85% RH). The model was validated by a further series of independent controlled environment experiments where both RH and temperature were varied and generally simulated the pattern of disease development well. The implications of the results in terms of Sclerotinia disease forecasting are discussed. PMID:24736409

  10. Accelerated Testing and Modeling of Potential-Induced Degradation as a Function of Temperature and Relative Humidity

    DEFF Research Database (Denmark)

    Hacke, Peter; Spataru, Sergiu; Terwilliger, Kent

    2015-01-01

    An acceleration model based on the Peck equation was applied to power performance of crystalline silicon cell modules as a function of time and of temperature and humidity, which are the two main environmental stress factors that promote potential-induced degradation (PID). This model was derived...

  11. Accelerated Testing and Modeling of Potential-Induced Degradation as a Function of Temperature and Relative Humidity

    DEFF Research Database (Denmark)

    Hacke, Peter; Spataru, Sergiu; Terwilliger, Kent

    2015-01-01

    An acceleration model based on the Peck equation was applied to power performance of crystalline silicon cell modules as a function of time and of temperature and humidity, the two main environmental stress factors that promote potential-induced degradation. This model was derived from module pow...

  12. Performance Characteristics of a PEM Fuel Cell with Parallel Flow Channels at Different Cathode Relative Humidity Levels

    Directory of Open Access Journals (Sweden)

    Sang Soon Hwang

    2009-11-01

    Full Text Available In fuel cells flow configuration and operating conditions such as cell temperature, humidity at each electrode and stoichiometric number are very crucial for improving performance. Too many flow channels could enhance the performance but result in high parasite loss. Therefore a trade-off between pressure drop and efficiency of a fuel cell should be considered for optimum design. This work focused on numerical simulation of the effects of operating conditions, especially cathode humidity, with simple micro parallel flow channels. It is known that the humidity at the cathode flow channel becomes very important for enhancing the ion conductivity of polymer membrane because fully humidified condition was normally set at anode. To investigate the effect of humidity on the performance of a fuel cell, in this study humidification was set to 100% at the anode flow channel and was changed by 0–100% at the cathode flow channel. Results showed that the maximum power density could be obtained under 60% humidified condition at the cathode where oxygen concentration was moderately high while maintaining high ion conductivity at a membrane.

  13. Effects of humidity and interlayer cations on the frictional strength of montmorillonite

    Science.gov (United States)

    Tetsuka, Hiroshi; Katayama, Ikuo; Sakuma, Hiroshi; Tamura, Kenji

    2018-04-01

    We developed a humidity control system in a biaxial friction testing machine to investigate the effect of relative humidity and interlayer cations on the frictional strength of montmorillonite. We carried out the frictional experiments on Na- and Ca-montmorillonite under controlled relative humidities (ca. 10, 30, 50, 70, and 90%) and at a constant temperature (95 °C). Our experimental results show that frictional strengths of both Na- and Ca-montmorillonite decrease systematically with increasing relative humidity. The friction coefficients of Na-montmorillonite decrease from 0.33 (at relative humidity of 10%) to 0.06 (at relative humidity of 93%) and those of Ca-montmorillonite decrease from 0.22 (at relative humidity of 11%) to 0.04 (at relative humidity of 91%). Our results also show that the frictional strength of Na-montmorillonite is higher than that of Ca-montmorillonite at a given relative humidity. These results reveal that the frictional strength of montmorillonite is sensitive to hydration state and interlayer cation species, suggesting that the strength of faults containing these clay minerals depends on the physical and chemical environment.[Figure not available: see fulltext.

  14. Performance analysis of spring wheat genotypes under rain-fed conditions in warm humid environment of Nepal

    Directory of Open Access Journals (Sweden)

    Ramesh Raj Puri

    2015-06-01

    Full Text Available Around 25% of total wheat area in Terai of Nepal falls under rain-fed and partially irrigated condition. A Coordinated varietal trial (CVT was conducted during two consecutive crop cycles (2011-12 and 2012-13 under timely sown rain-fed conditions of Terai. The trial was conducted in Alpha Lattice design with two replications at Nepal Agricultural Research Council, National Wheat Research Program, Bhairahawa and Nepal Agricultural Research Council, Regional Agriculture Research Station, Nepalgunj. Observations were recorded for yield and yield traits and analyzed using statistical software Cropstat 7.2.The combined analysis of coordinated varietal trial showed that BL 3978 possessed the highest yield (2469.2 Kg ha-1 followed by NL 1097 (2373.2 Kg ha-1 and NL 1094 (2334.06 Kg ha-1. Genotype x Environment interaction for grain yield was significant (p<0.05 over locations and years. BL 3978 with early maturity (111 days escaped the heat stress environment. Among the top three genotypes, BL 3978 was consistently higher in both favorable and unfavorable conditions. Earliness was one of the major traits for heat tolerant genotypes. The three identified genotypes will be further evaluated in participatory varietal selection or coordinated farmers field trial followed by small plot seed multiplication (seed increase and release in the future for timely sown rain-fed conditions. These lines also appear suitable for inclusion in crossing program targeted for water stress tolerance variety development. DOI: http://dx.doi.org/10.3126/ije.v4i2.12649 International Journal of Environment Vol.4(2 2015: 289-295

  15. Humidity control of an incubator using the microcontroller-based active humidifier system employing an ultrasonic nebulizer.

    Science.gov (United States)

    Güler, I; Burunkaya, M

    2002-01-01

    Relative humidity levels of an incubator were measured and controlled. An ultrasonic nebulizer system as an active humidifier was used to humidify the incubator environment. An integrated circuit-type humidity sensor was used to measure the humidity level of the incubator environment. Measurement and control processes were achieved by a PIC microcontroller. The high-performance and high-speed PIC provided the flexibility of the system. The developed system can be used effectively for the intensive care of newborns and/or premature babies. Since the humidifier generates an aerosol in ambient conditions, it is possible to provide the high relative humidity level for therapeutic and diagnostic purposes in medicine.

  16. Gas/aerosol Partitioning Parameterisation For Global Modelling: A Physical Interpretation of The Relationship Between Activity Coefficients and Relative Humidity

    Science.gov (United States)

    Metzger, S.; Dentener, F. J.; Lelieveld, J.; Pandis, S. N.

    A computationally efficient model (EQSAM) to calculate gas/aerosol partitioning ofsemi-volatile inorganic aerosol components has been developed for use in global- atmospheric chemistry and climate models; presented at the EGS 2001.We introduce and discuss here the physics behind the parameterisation, upon whichthe EQuilib- rium Simplified Aerosol Model EQSAM is based. The parameterisation,which ap- proximates the activity coefficient calculation sufficiently accurately forglobal mod- elling, is based on a method that directly relates aerosol activitycoefficients to the ambient relative humidity, assuming chemical equilibrium.It therefore provides an interesting alternative for the computationally expensiveiterative activity coefficient calculation methods presently used in thermodynamicgas/aerosol equilibrium mod- els (EQMs). The parameterisation can be used,however, also in dynamical models that calculate mass transfer between theliquid/solid aerosol phases and the gas/phase explicitly; dynamical models oftenincorporate an EQM to calculate the aerosol com- position. The gain of theparameterisation is that the entire system of the gas/aerosol equilibrium partitioningcan be solved non-iteratively, a substantial advantage in global modelling.Since we have already demonstrated at the EGS 2001 that EQSAM yields similarresults as current state-of-the-art equilibrium models, we focus here on a dis- cussionof our physical interpretation of the parameterisation; the identification of theparameters needed is crucial. Given the lag of reliable data, the best way tothor- oughly validate the parameterisation for global modelling applications is theimple- mentation in current state-of-the-art gas/aerosol partitioning routines, whichare embe- ded in e.g. a global atmospheric chemistry transport model, by comparingthe results of the parameterisation against the ones based on the widely used activitycoefficient calculation methods (i.e. Bromley, Kussik-Meissner or Pitzer). Then

  17. Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

    Directory of Open Access Journals (Sweden)

    T. Liu

    2018-04-01

    Full Text Available The formation of secondary organic aerosol (SOA has been widely studied in the presence of dry seed particles at low relative humidity (RH. At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm−3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm−3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m ∕ z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS, indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory

  18. Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles at moderate relative humidity

    Science.gov (United States)

    Liu, Tengyu; Huang, Dan Dan; Li, Zijun; Liu, Qianyun; Chan, ManNin; Chan, Chak K.

    2018-04-01

    The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, initially dry seed particles can exist as wet particles due to water uptake by the seeds as well as the SOA. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor in the absence of NOx under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. The ratio of the SOA yield on wet AS seeds to that on dry AS seeds, the relative SOA yield, decreased from 1.31 ± 0.02 at an OH exposure of 4.66 × 1010 molecules cm-3 s to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm-3 s. This decrease may be due to the early deliquescence of initially dry AS seeds after being coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after SOA formed, and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased, especially at high OH exposure. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m / z 29, 43 and 44 of SOA mass spectra, obtained using an aerosol mass spectrometer (AMS), indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that inorganic dry seeds become at least partially deliquesced particles during SOA formation and hence that ALW is inevitably involved in the SOA formation at moderate RH. More laboratory experiments conducted with a wide variety of SOA precursors

  19. Colorimetric humidity sensor based on liquid composite materials for the monitoring of food and pharmaceuticals.

    Science.gov (United States)

    Bridgeman, Devon; Corral, Javier; Quach, Ashley; Xian, Xiaojun; Forzani, Erica

    2014-09-09

    Using supported ionic-liquid membrane (SILM)-inspired methodologies, we have synthesized, characterized, and developed a humidity sensor by coating a liquid composite material onto a hygroscopic, porous substrate. Similar to pH paper, the sensor responds to the environment's relative humidity and changes color accordingly. The humidity indicator is prepared by casting a few microliters of low-toxicity reagents on a nontoxic substrate. The sensing material is a newly synthesized liquid composite that comprises a hygroscopic medium for environmental humidity capture and a color indicator that translates the humidity level into a distinct color change. Sodium borohydride was used to form a liquid composite medium, and DenimBlu30 dye was used as a redox indicator. The liquid composite medium provides a hygroscopic response to the relative humidity, and DenimBlu30 translates the chemical changes into a visual change from yellow to blue. The borate-redox dye-based humidity sensor was prepared, and then Fourier transform infrared spectroscopy, differential scanning calorimetry, and image analysis methods were used to characterize the chemical composition, optimize synthesis, and gain insight into the sensor reactivity. Test results indicated that this new sensing material can detect relative humidity in the range of 5-100% in an irreversible manner with good reproducibility and high accuracy. The sensor is a low-cost, highly sensitive, easy-to-use humidity indicator. More importantly, it can be easily packaged with products to monitor humidity levels in pharmaceutical and food packaging.

  20. Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: investigation of sucrose-citric acid mixtures.

    Science.gov (United States)

    Kwok, Kaho; Mauer, Lisa J; Taylor, Lynne S

    2010-11-24

    Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.

  1. Effects of anticaking agents and relative humidity on the physical and chemical stability of powdered vitamin C.

    Science.gov (United States)

    Lipasek, Rebecca A; Taylor, Lynne S; Mauer, Lisa J

    2011-09-01

    Vitamin C is an essential nutrient that is widely used by the food industry in the powder form for both its nutritional and functional properties. However, vitamin C is deliquescent, and deliquescence has been linked to physical and chemical instabilities. Anticaking agents are often added to powder systems to delay or prevent caking, but little is known about their effect on the chemical stability of powders. In this study, various anticaking agents (calcium phosphate, calcium silicate, calcium stearate, corn starch, and silicon dioxide) were combined with sodium ascorbate at 2% and 50% w/w ratios and stored at various relative humidities (23%, 43%, 64%, 75%, 85%, and 98% RHs). Chemical and physical stability and moisture sorption were monitored over time. Additionally, saturated solution samples were stored at various pHs to determine the effect of surface pH and dissolution on the vitamin degradation rate. Storage RH, time, and anticaking agent type and ratio all significantly affected (P vitamin C stability. Silicon dioxide and calcium silicate (50% w/w) and calcium stearate (at both ratios) were the only anticaking agents to improve the physical stability of powdered sodium ascorbate while none of the anticaking agents improved its chemical stability. However, corn starch and calcium stearate had the least adverse effect on chemical stability. Dissolution rate and pH were also important factors affecting the chemical and physical stability of the powders. Therefore, monitoring storage environmental conditions and anticaking agent usage are important for understanding the stability of vitamin C. Anticaking agent type and ratio significantly affected the physical and chemical stability of vitamin C over time and over a range of RHs. No anticaking agent improved the chemical stability of the vitamin, and most caused an increase in chemical degradation even if physical stability was improved. It is possible that anticaking agents would greatly affect other

  2. METEO-P/H: Measuring ambient pressure and relative humidity on the ExoMars 2020 landing site

    Science.gov (United States)

    Nikkanen, T. T.; Genzer, M.; Hieta, M.; Harri, A.-M.; Haukka, H.; Polkko, J.; Kynkäänniemi, T.

    2017-09-01

    Finnish Meteorological Institute (FMI) has designed and is in the process of building and testing a pressure and humidity measurement device for the ExoMars 2020 lander. The ExoMars 2020 mission consists of the Russian Roscosmos Surface Platform (SP) and the European Space Agency (ESA) Rover. The Surface Platform will perform the Entry, Descent and Landing for the lander combo and start stationary science operations after landing, while the Rover will drive off the SP to explore the landing site surroundings and soil. The FMI measurement device is installed on the Surface Platform to give continuous measurements from a stationary location. The METEO-P pressure device and METEO-H humidity device are part of the METEO meteorological science package, which also includes a thermometer and an anemometer from IKI, Russia, as well as the RDM Radiation and dust sensors, and the AMR magnetic field sensors from INTA, Spain.

  3. Exploring the effects of symmetrical and asymmetrical relative humidity on the performance of H{sub 2}/air PEM fuel cell at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Saleh, Mahmoud M.; Okajima, Takeoshi; Kitamura, Fusao; Ohsaka, Takeo [Department of Electronic Chemistry, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Hayase, Masahiko [Development Department, NF Co., 6-3-20 Tsunashima-higashi, Kohoku-ku, Yokohama 223-8508 (Japan)

    2007-02-10

    This article is dedicated to study the interlinked effects of symmetric relative humidity (RH), and asymmetric RH on the performance of H{sub 2}/air PEM fuel cell at different temperatures. The symmetric and asymmetric RH were achieved by setting the cathode relative humidity (RHC) and anode relative humidity (RHA) as equal and unequal values, respectively. The cell performance was evaluated by collecting polarization curves of the cell at different RH, RHC and RHA and at different cell temperatures (T{sub cell}). The polarization curves along with the measured internal cell resistance (membrane resistance) were discussed in the light of the present fuel cell theory. The results showed that symmetric relative humidity has different impacts depending on the cell temperature. While at RH of 35% the cell can show considerable performance at T{sub cell} = 70 C, it is not so at T{sub cell} = 90 C. At T{sub cell} = 70 C, the cell potential increases with RH at lower and medium current densities but decreases with RH at higher currents. This was attributed to the different controlling processes at higher and lower current densities. This trend at 70 C is completely destroyed at 90 C. Operating our PEM fuel cell at dry H{sub 2} gas conditions (RHA = 0%) is not detrimental as operating the cell at dry Air (O{sub 2}) conditions (RHC = 0%). At RHA = 0% and humidified air, water transport by back diffusion from the cathode to the anode at the employed experimental conditions can support reasonable rehydration of the membrane and catalysts. At RHA = 0, a possible minimum RHC for considerable cell operation is temperature dependent. At RHC = 0 conditions, the cell can operate only at RHA = 100% with a loss that depends on T{sub cell}. It was found that the internal cell resistance depends on RH, RHA, RHC and T{sub cell} and it is consistent with the observed cell performance. (author)

  4. PSYCRODATA: a software which calculates the air humidity characteristics and relate its with the variations of the gamma environmental bottom

    International Nuclear Information System (INIS)

    Alonso A, D.; Dominguez L, O.; Ramos V, O.; Caveda R, C.A.; Capote F, E.; Dominguez G, A.; Valdes S, E.; Rodriguez V, E.

    2006-01-01

    The computer tool 'Psycrodata', able to calculate the values of those characteristics of the humidity of the air starting from the measurements carried out of humidity and temperature in the post of occident of the National Net of Environmental Radiological Surveillance was obtained. Among the facilities that 'Psycrodata' toasts it is the keeping the obtained information in a database facilitating the making of reports. For another part the possibility of selection of different approaches for the calculation and the introduction of the psicrometric coefficient to use, its make that each station can have the suitable psicrometric chart keeping in mind the instrumentation and the characteristics of the area of location of the same one. Also, can have facilities to import text files for later on to be plotted, it allowed to correlate the absorbed dose rate in air due to the environmental gamma radiation, besides of the temperature and the humidity, with the tension of the water steam, the temperature of the dew point and the saturation deficit. (Author)

  5. Effect of temperature and relative humidity on the water vapour permeability and mechanical properties of cassava starch and soy protein concentrate based edible films.

    Science.gov (United States)

    Chinma, C E; Ariahu, C C; Alakali, J S

    2015-04-01

    The effect of temperature and relative humidity on the water vapour permeability (WVP) and mechanical properties of cassava starch and soy protein concentrate (SPC) based edible films containing 20 % glycerol level were studied. Tensile strength and elastic modulus of edible films increased with increase in temperature and decreased with increase in relative humidity, while elongation at break decreased. Water vapour permeability of the films increased (2.6-4.3 g.mm/m(2).day.kPa) with increase in temperature and relative humidity. The temperature dependence of water vapour permeation of cassava starch-soy protein concentrate films followed Arrhenius relationship. Activation energy (Ea) of water vapour permeation of cassava starch-soy protein concentrate edible films ranged from 1.9 to 5.3 kJ/mol (R (2)  ≥ 0.93) and increased with increase in SPC addition. The Ea values were lower for the bio-films than for polyvinylidene chloride, polypropylene and polyethylene which are an indication of low water vapour permeability of the developed biofilms compared to those synthetic films.

  6. Investigating the effect of gas flow rate, inlet ozone concentration and relative humidity on the efficacy of catalytic ozonation process in the removal of xylene from waste airstream

    Directory of Open Access Journals (Sweden)

    H.R. MokaramI

    2010-10-01

    Full Text Available Background and aimsThe catalytic ozonation is an efficient process for the degradation of volatile organic compounds from contaminated air stream. This study was aimed at investigating the efficacy of catalytic ozonation process in removal of xylene from the polluted air stream andthe influence of retention time (gas flow rate, inlet ozone dose and relative humidity on this performanceMethodsthe catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selectedoperational variables.ResultsThe results indicated that the efficiency of catalytic ozonation was greater than that of single adsorption in removal of xylene under similar inlet concentration and relative humidity. We found a significant catalytic effect for activated carbon when used in combination with ozonation process, leading to improvement of xylene removal percentage. In addition, the elimination capacity of the system improved with the increase of inlet ozone dose as well as gas flow rate. The relative humidity showed a positive effect of the xylene removal at the range of 5 to 50%, while the higher humidity (more than 50% resulted in reduction of the performance.ConclusionThe findings of the present work revealed that the catalytic ozonation process can be an efficient technique for treating the air streams containing industrial concentrations of xylene. Furthermore, there is a practical potential to retrofit the present adsorption systems intothe catalytic ozonation simply by coupling them with the ozonation system. the catalytic ozonation of xylene was conducted using a bench scale set-up consisted of a syringe pump,an air pump, an ozone generator, and a glass reactor packed with activated carbon. Several experimental run was defined to investigate the influence of the selected

  7. High relative humidity in-package of fresh-cut fruits and vegetables: advantage or disadvantage considering microbiological problems and antimicrobial delivering systems?

    Science.gov (United States)

    Ayala-Zavala, J F; Del-Toro-Sánchez, L; Alvarez-Parrilla, E; González-Aguilar, G A

    2008-05-01

    This hypothesis article states that the high relative humidity (RH) of packaged fresh-cut fruits or vegetables that is associated with spoilage can be used as an advantageous way to deliver antimicrobial compounds using cyclodextrins (CDs) as carriers. CDs can function as antimicrobial delivery systems as they can release antioxidant and antimicrobial compounds (guest molecules) as the humidity levels increase in the headspace. Hydrophobic antimicrobial guests can be complexed with CDs due to the amphiphatic nature of the host. Then, at high RH values, due to the water-CDs interaction, host-guest interactions are weakened; consequently, the antimicrobial molecule is released and should protect the product against the microbial growth. Potential antimicrobial compounds capable of forming complexes with CDs are discussed, as well as possible applications to preserve fresh-cut produce and future research in this area.

  8. Humidity and Buildings. Technical Paper No. 188.

    Science.gov (United States)

    Hutcheon, N. B.

    Modified and controlled relative humidity in buildings for certain occupancies is discussed. New criteria are used in determining the needs, desirability and problems associated with humidities in a building. Severe winter climate requires that special attention be given to the problems associated with increased indoor humidities during cold…

  9. 40 CFR 89.326 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air... type of intake air supply, the humidity measurements must be made within the intake air supply system...

  10. 40 CFR 91.310 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Provisions § 91.310 Engine intake air humidity measurement. This section refers to engines which are supplied... air, the ambient testcell humidity measurement may be used. (a) Humidity conditioned air supply. Air...

  11. 40 CFR 90.310 - Engine intake air humidity measurement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Emission Test Equipment Provisions § 90.310 Engine intake air humidity measurement. This section refers to... for the engine intake air, the ambient test cell humidity measurement may be used. (a) Humidity...

  12. Fuel Oxidizer Reaction Products (FORP) Contamination of Service Module (SM) and Release of N-nitrosodimethylamine(NDMA)in a Humid Environment from Crew EVA Suits Contaminated with FORP

    Science.gov (United States)

    Schmidl, William; Mikatarian, Ron; Lam, Chiu-Wing; West, Bil; Buchanan, Vanessa; Dee, Louis; Baker, David; Koontz, Steve

    2004-01-01

    The Service Module (SM) is an element of the Russian Segment of the International Space Station (ISS). One of the functions of the SM is to provide attitude control for the ISS using thrusters when the U.S. Control Moment Gyros (CMG's) must be desaturated. Prior to an Extravehicular Activity (EVA) on the Russian Segment, the Docking Compartment (DC1) is depressurized, as it is used as an airlock. When the DC1 is depressurized, the CMG's margin of momentum is insufficient and the SM attitude control thrusters need to fire to desaturate the CMG's. SM roll thruster firings induce contamination onto adjacent surfaces with Fuel Oxidizer Reaction Products (FORP). FORP is composed of both volatile and non-volatile components. One of the components of FORP is the potent carcinogen N-nitrosdimethylamine (NDMA). Since the EVA crewmembers often enter the area surrounding the thrusters for tasks on the aft end of the SM and when translating to other areas of the Russian Segment, the presence of FORP is a concern. This paper will discuss FORP contamination of the SM surfaces, the release of NDMA in a humid environment from crew EVA suits, if they happen to be contaminated with FORP, and the toxicological risk associated with the NDMA release.

  13. Temperatura e umidade relativa na qualidade da tangerina "Montenegrina" armazenada Temperature and relative humidity during cold storage of 'Montenegrina' tangerine

    Directory of Open Access Journals (Sweden)

    Auri Brackmann

    2008-04-01

    Full Text Available O presente trabalho foi conduzido com o objetivo de avaliar o efeito da temperatura e da umidade relativa do ar (UR sobre a manutenção da qualidade de tangerinas durante o período de armazenamento refrigerado (AR. O delineamento experimental utilizado foi inteiramente casualizado, em esquema bifatorial, com oito repetições, contendo 15 frutos cada. Os tratamentos avaliados constituíram-se da combinação das temperaturas 2, 3 e 4°C, com UR do ar de 90 e 96%. Após oito e 12 semanas de armazenamento, mais três dias de exposição a 20°C, foram realizadas as seguintes análises: acidez total titulável (ATT, sólidos solúveis totais (SST, consistência dos frutos, incidência de podridões e suculência. De acordo com os resultados obtidos, os frutos armazenados a 3°C + UR do ar de 90% apresentaram ATT, SST e consistência mais elevada, após oito e 12 semanas de AR. A incidência de podridão foi significativamente superior nos tratamentos com alta UR do ar (96%. Injúrias provocadas pela baixa temperatura ocorreram em alguns frutos no tratamento a 2°C. Não se constatou diferença significativa na suculência entre os tratamentos em ambas as datas de avaliação. A temperatura de 3°C combinada com UR de 90% apresentou os melhores resultados na conservação de tangerinas "Montenegrina", que podem ser armazenadas por um período de até oito semanas.This research was conducted in order to evaluate the effect of temperature and relative humidity (RH on the quality of tangerines during cold storage. The experimental design was entirely randomized, in a bifatorial design with eight replications of 15 fruits. The treatments were the combination of three temperatures (2, 3 and 4oC and two RH levels (90 and 96%. Evaluations of quality were performed after 8 and 12 weeks of cold storage plus 3 days of shelf life at 20°C. The analyzed parameters were: total titratable acidity (TTA, total soluble solids (TSS, fruits consistency, rot

  14. Inorganic-based proton conductive composite membranes for elevated temperature and reduced relative humidity PEM fuel cells

    Science.gov (United States)

    Wang, Chunmei

    Proton exchange membrane (PEM) fuel cells are regarded as highly promising energy conversion systems for future transportation and stationary power generation and have been under intensive investigations for the last decade. Unfortunately, cutting edge PEM fuel cell design and components still do not allow economically commercial implementation of this technology. The main obstacles are high cost of proton conductive membranes, low-proton conductivity at low relative humidity (RH), and dehydration and degradation of polymer membranes at high temperatures. The objective of this study was to develop a systematic approach to design a high proton conductive composite membrane that can provide a conductivity of approximately 100 mS cm-1 under hot and dry conditions (120°C and 50% RH). The approach was based on fundamental and experimental studies of the proton conductivity of inorganic additives and composite membranes. We synthesized and investigated a variety of organic-inorganic Nafion-based composite membranes. In particular, we analyzed their fundamental properties, which included thermal stability, morphology, the interaction between inorganic network and Nafion clusters, and the effect of inorganic phase on the membrane conductivity. A wide range of inorganic materials was studied in advance in order to select the proton conductive inorganic additives for composite membranes. We developed a conductivity measurement method, with which the proton conductivity characteristics of solid acid materials, zirconium phosphates, sulfated zirconia (S-ZrO2), phosphosilicate gels, and Santa Barbara Amorphous silica (SBA-15) were discussed in detail. Composite membranes containing Nafion and different amounts of functionalized inorganic additives (sulfated inorganics such as S-ZrO2, SBA-15, Mobil Composition of Matter MCM-41, and S-SiO2, and phosphonated inorganic P-SiO2) were synthesized with different methods. We incorporated inorganic particles within Nafion clusters

  15. Public Relations - 2003 Energy and Environment Calendar

    International Nuclear Information System (INIS)

    Novosel, N.; Valcic, I.

    2003-01-01

    Ministry of Economy in co-operation with the Ministry of Education and Sport, Croatian Electric Utility and Enconet International during the year 2002 realized the project of preparing the calendar for 2003 containing primary school pupils' paintings about energy and environment and additional information about preparedness in the Republic of Croatia in the case of nuclear accident and recommendations for acting. The calendar is primarily created for families living in the circle 25 km from the Nuclear Power Plant Krsko and will be distributed to all pupils of primary schools on that territory. Therefore the collecting of paintings was carried out between pupils from fifth to eight grades in those schools. Expert commission chose twelve best paintings from fifty-two collected and ceremonial promotion of the calendar was held in the Technical museum in Zagreb. This kind of project is only one example of public relations with the purpose of knowledge building about successful living together with energy technologies. In this text the course of the project of realizing the calendar will be presented with the special accent on content and purpose of the text about preparedness in the Republic of Croatia in the case of nuclear accident and recommendations for acting. (author)

  16. Environment-related expenditures in 2013

    International Nuclear Information System (INIS)

    Diel, Olivier

    2015-12-01

    In 2013, households, private corporations and general government spent Euro 47.2 billion for environmental protection, an increase of 1.8% over 2012. For the 2000-2013 period on the whole, this expenditure has been rising faster than the gross domestic product (GDP): +4% on an annual average for the environmental protection expenditure compared with +2.8% for the GDP. In connection with the growing environmental concerns of society, public policy contributed to this steady increase through economic incentives ('bonus/malus' system, for instance) and regulation. In particular, the latter led to a technical improvement of processes (selective collection of waste, bringing up to standard of water treatment plants) which participated in the growth of expenditure. Wastewater and waste managements are the two main environmental protection expenditure domains. Furthermore, they are connected with topics related to resource management: drinking water supply and materials recovery. However, the expenditure for the materials recovery sector is decreasing in 2013, due to declines in raw materials prices. Expenditure for renewable energies - another topic related to environment - is considerably growing in 2013. Electricity production notably from water power is rising sharply, as a result of a particularly rainy spring. Nevertheless, the growth of environmental expenditures does not impact the corresponding employment in a systematic way. Thus, even if value added of the environmental goods and services sector (EGSS) increased by 1.8% in 2013, employment decreased by 0.3%. And the labor market in the green economy has been in decay since 2011, at a practically similar rate as for the economy as a whole

  17. Unimodal models to relate species to environment

    NARCIS (Netherlands)

    Braak, ter C.J.F.

    1987-01-01

    To assess the impact of environmental change on biological communities knowledge about species-environment relationships is indispensable. Ecologists attempt to uncover the relationships between species and environment from data obtained from field surveys. In the survey, species are scored on their

  18. Tree-ring stable carbon isotope-based April-June relative humidity reconstruction since ad 1648 in Mt. Tianmu, China

    Science.gov (United States)

    Liu, Yu; Ta, Weiyuan; Li, Qiang; Song, Huiming; Sun, Changfeng; Cai, Qiufang; Liu, Han; Wang, Lu; Hu, Sile; Sun, Junyan; Zhang, Wenbiao; Li, Wenzhu

    2018-03-01

    Based on accurate dating, we have determined the stable carbon isotope ratios (δ13C) of five Cryptomeria fortunei specimens from Mt. Tianmu, a subtropical area in southern China. The five δ13C time series records are combined into a single representative δ13C time series using a "numerical mix method." These are normalized to remove temporal variations of δ13 C in atmospheric CO2 to obtain a carbon isotopic discrimination (Δ13C) time series, in which we observe a distinct correlation between Δ13C and local April to June mean relative humidity ( RH AMJ ) (n = 64, r = 0.858, p use this relationship to reconstruct RH AMJ variations from ad 1648 to 2014 at Mt. Tianmu. The reconstructed sequence show that over the past 367 years, Mt. Tianmu area was relatively wet, but in the latter part of the twentieth century, under the influence of increasing global warming, it has experienced a sharp reduction in relative humidity. Spatial correlation analysis reveals a significant negative correlation between RH AMJ at Mt. Tianmu and Sea Surface Temperature (SSTs) in the western equatorial Pacific and Indian Ocean. In other words, there is a positive correlation between tree-ring δ13C in Mt. Tianmu and SSTs. Both observed and reconstructed RH AMJ show significant positive correlations with East Asian and South Asian monsoons from 1951 to 2014, which indicate that RH AMJ from Mt. Tianmu reflects the variability of the Asian summer monsoon intensity to a great extent. The summer monsoon has weakened since 1960. However, an increase in relative humidity since 2003 implies a recent enhancement in the summer monsoon.

  19. The Environment and the Relative Protection Programs

    Directory of Open Access Journals (Sweden)

    Constantin Anghelache

    2007-12-01

    Full Text Available The material is presenting, under an adequate structure, an analysis of the environment of Romania. The starting point of the study is given by the natural conditions, influenced by the geographic location of Romania on the globe, evidencing the main characteristics (relief, hydrographic basin, climate, flora and fauna etc.. Afterwards, the material is pointing out the concerns as well as certain outcomes achieved in our country in the field of the environment protection. Particularly, there is the concern regarding the durable development which is emphasized, along with the part that the environment protection should play under the circumstances. Then, the material is evidencing the essence of the policies concerning the environment protection as well as the transitory steps implied in this field by the adhesion of Romania to the European Union.

  20. The Vertical Structure of Relative Humidity and Ozone in the Tropical Upper Troposphere: Intercomparisons Among In Situ Observations, A-Train Measurements and Large-Scale Models

    Science.gov (United States)

    Selkirk, Henry B.; Manyin, Michael; Douglass, Anne R.; Oman, Luke; Pawson, Steven; Ott, Lesley; Benson, Craig; Stolarski, Richard

    2010-01-01

    In situ measurements in the tropics have shown that in regions of active convection, relative humidity with respect to ice in the upper troposphere is typically close to saturation on average, and supersaturations greater than 20% are not uncommon. Balloon soundings with the cryogenic frost point hygrometer (CFH) at Costa Rica during northern summer, for example, show this tendency to be strongest between 11 and 15.5 km (345-360 K potential temperature, or approximately 250-120 hPa). this is the altitude range of deep convective detrainment. Additionally, simultaneous ozonesonde measurements show that stratospheric air (O3 greater than 150 ppbv) can be found as low as approximately 14 km (350 K/150 hPa). In contrast, results from northern winter show a much drier upper troposphere and little penetration of stratospheric air below the tropopause at 17.5 km (approximately 383 K). We show that these results are consistent with in situ measurements from the Measurement of Ozone and water vapor by Airbus In-service airCraft (MOZAIC) program which samples a wider, though still limited, range of tropical locations. To generalize to the tropics as a whole, we compare our insitu results to data from two A-Train satellite instruments, the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS) on the Aqua and Aura satellites respectively. Finally, we examine the vertical structure of water vapor, relative humidity and ozone in the NASA Goddard MERRA analysis, an assimilation dataset, and a new version of the GEOS CCM, a free-running chemistry-climate model. We demonstrate that conditional probability distributions of relative humidity and ozone are a sensitive diagnostic for assessing the representation of deep convection and upper troposphere/lower stratosphere mixing processes in large-scale analyses and climate models.

  1. Effect of concentration, exposure time, temperature, and relative humidity on the toxicity of sulfur dioxide to the spores of Botrytis cinerea

    Energy Technology Data Exchange (ETDEWEB)

    Couey, H.M.; Uota, M.

    1961-12-01

    When spores of Botrytis cinerea are exposed to SO/sub 2/ gas, the subsequent reduction in spore germination is quantitatively proportional to the SO/sub 2/ concentration and the exposure time. The toxicity of SO/sub 2/ increases with increasing relative humidity. In an atmosphere of 96% RH, SO/sub 2/ is more than 20 times as effective as at 75% RH. The toxicity also increases about 1.5 times for each 10/sup 0/C rise in temperature between 0/sup 0/ and 30/sup 0/C. 8 references, 4 figures, 1 table.

  2. GPM GROUND VALIDATION METEOROLOGICAL TOWER ENVIRONMENT CANADA GCPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation Meteorological Tower Environment Canada GCPEx dataset provides temperature, relative humidity, 10 m winds, pressure and solar radiation...

  3. Effect of high relative humidity on dried Plantago lanceolata L. leaves during long-term storage: effects on chemical composition, colour and microbiological quality.

    Science.gov (United States)

    Gonda, Sándor; Tóth, László; Gyémánt, Gyöngyi; Braun, Mihály; Emri, Tamás; Vasas, Gábor

    2012-01-01

    Modern phytotherapy and quality assurance requires stability data on bioactive metabolites to identify and minimise decomposing factors during processing and storage. A compound's stability in a complex matrix can be different from the stability of the purified compound. To test the stability of iridoids and acteoside and quantify changes in colour and microbiological quality in a common herbal tea, dried P. lanceolata leaves during exposure to high-humidity air. To test the contribution of fungi to metabolite decomposition. Dried P. lanceolata leaves were exposed to atmospheres of different relative humidity (75, 45 and 0%) for 24 weeks. Changes in aucubin and catalpol concentration were determined by CE-MEKC, and those in acteoside on TLC. Colour and chlorophyll-like pigments were measured by different spectrophotometric methods. The number of fungi was monitored; 10 strains were isolated from the plant drug, and their ability to decompose the analytes of interest was tested. During incubation at 75% relative humidity (RH), aucubin, catalpol and acteoside concentrations decreased by 95.7, 97.0 and 70.5%, respectively. Strong shifts were detected in CIELAB parameters a* and b* (browning) as a result of conversion of chlorophyll to pheophytin. Intensive microbial proliferation was also observed. Changes at 45 or 0% RH were typically insignificant. Seven of the 10 isolated fungal strains could decompose both iridoids, and five could decompose acteoside in vitro. It was shown that exposure to water results in loss of bioactive molecules of P. lanceolata dried leaves, and that colonising fungi are the key contributors to this loss. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Nonlinear empirical model of gas humidity-related voltage dynamics of a polymer-electrolyte-membrane fuel cell stack

    Science.gov (United States)

    Meiler, M.; Andre, D.; Schmid, O.; Hofer, E. P.

    Intelligent energy management is a cost-effective key path to realize efficient automotive drive trains [R. O'Hayre, S.W. Cha, W. Colella, F.B. Prinz. Fuel Cell Fundamentals, John Wiley & Sons, Hoboken, 2006]. To develop operating strategy in fuel cell drive trains, precise and computational efficient models of all system components, especially the fuel cell stack, are needed. Should these models further be used in diagnostic or control applications, then some major requirements must be fulfilled. First, the model must predict the mean fuel cell voltage very precisely in all possible operating conditions, even during transients. The model output should be as smooth as possible to support best efficient optimization strategies of the complete system. At least, the model must be computational efficient. For most applications, a difference between real fuel cell voltage and model output of less than 10 mV and 1000 calculations per second will be sufficient. In general, empirical models based on system identification offer a better accuracy and consume less calculation resources than detailed models derived from theoretical considerations [J. Larminie, A. Dicks. Fuel Cell Systems Explained, John Wiley & Sons, West Sussex, 2003]. In this contribution, the dynamic behaviour of the mean cell voltage of a polymer-electrolyte-membrane fuel cell (PEMFC) stack due to variations in humidity of cell's reactant gases is investigated. The validity of the overall model structure, a so-called general Hammerstein model (or Uryson model), was introduced recently in [M. Meiler, O. Schmid, M. Schudy, E.P. Hofer. Dynamic fuel cell stack model for real-time simulation based on system identification, J. Power Sources 176 (2007) 523-528]. Fuel cell mean voltage is calculated as the sum of a stationary and a dynamic voltage component. The stationary component of cell voltage is represented by a lookup-table and the dynamic voltage by a parallel placed, nonlinear transfer function. A

  5. Humidity fluctuations in the marine boundary layer measured at a coastal site with an infrared humidity sensor

    DEFF Research Database (Denmark)

    Sempreviva, A.M.; Gryning, Sven-Erik

    1996-01-01

    An extensive set of humidity turbulence data has been analyzed from 22-m height in the marine boundary layer. Fluctuations of humidity were measured by an ''OPHIR'', an infrared humidity sensor with a 10 Hz scanning frequency and humidity spectra were produced. The shapes of the normalized spectra...... follow the established similarity functions. However the 10-min time averaged measurements underestimate the value of the absolute humidity. The importance of the humidity flux contribution in a marine environment in calculating the Obukhov stability length has been studied. Deviations from Monin......-Obukhov similarity theory seem to be connected to a low correlation between humidity and temperature....

  6. Dynamics of Penicillium camemberti growth quantified by real-time PCR on Camembert-type cheeses under different conditions of temperature and relative humidity.

    Science.gov (United States)

    Leclercq-Perlat, Marie-Noëlle; Picque, Daniel; Martin Del Campo Barba, Sandra Teresita; Monnet, Christophe

    2013-06-01

    Penicillium camemberti plays a major role in the flavor and appearance of Camembert-type cheeses. However, little is known about its mycelium growth kinetics during ripening. We monitored the growth of P. camemberti mycelium in Camembert-type cheeses using real-time PCR in 4 ripening runs, performed at 2 temperatures (8 and 16°C) and 2 relative humidities (88 and 98%). These findings were compared with P. camemberti quantification by spore concentration. During the first phase, the mycelium grew but no spores were produced, regardless of the ripening conditions. During the second phase, which began when lactose was depleted, the concentration of spores increased, especially in the cheeses ripened at 16°C. Sporulation was associated with a large decrease in the mycelial concentration in the cheeses ripened at 16°C and 98% relative humidity. It was hypothesized that lactose is the main energy source for the growth of P. camemberti mycelium at the beginning of ripening and that its depletion would trigger stress, resulting in sporulation. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. The effect of combining a relative-humidity-sensitive ventilation system with the moisture-buffering capacity of materials on indoor climate and energy efficiency of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Woloszyn, Monika [Universite de Lyon, Lyon F-69003 (France); Universite Lyon1, Villeurbanne F-69622 (France); INSA-Lyon, CETHIL UMR CNRS 5008, bat. Sadi Carnot, F-69621 Villeurbanne cedex (France); Kalamees, Targo [Chair of Building Physics and Architecture, Tallinn University of Technology, Ehiteja tee 5 19086 (Estonia); Olivier Abadie, Marc [Pontifical Catholic University of Parana - PUCPR/CCET-Thermal Systems Laboratory, Rua Imaculada Conceicao, 1155 Curitiba, PR 80215-901 (Brazil); LEPTIAB-University of La Rochelle, Avenue M. Crepeau, 17000 La Rochelle (France); Steeman, Marijke [Department of Architecture and Urban Planning, UGENT-Ghent University, J. Plateaustraat 22, 9000 Ghent (Belgium); Sasic Kalagasidis, Angela [Department of Building Technology, Chalmers University of Technology, Sven Hultins gata 8, 412 96 Gothenburg (Sweden)

    2009-03-15

    Indoor moisture management, which means keeping the indoor relative humidity (RH) at correct levels, is very important for whole building performance in terms of indoor air quality (IAQ), energy performance and durability of the building. In this study, the effect of combining a relative-humidity-sensitive (RHS) ventilation system with indoor moisture buffering materials was investigated. Four comprehensive heat-air-moisture (HAM) simulation tools were used to analyse the performance of different moisture management strategies in terms of IAQ and of energy efficiency. Despite some differences in results, a good agreement was found and similar trends were detected from the results, using the four different simulation tools. The results from simulations demonstrate that RHS ventilation reduces the spread between the minimum and maximum values of the RH in the indoor air and generates energy savings. Energy savings are achieved while keeping the RH at target level, not allowing for possible risk of condensations. The disadvantage of this type of demand controlled-ventilation is that other pollutants (such as CO{sub 2}) may exceed target values. This study also confirmed that the use of moisture-buffering materials is a very efficient way to reduce the amplitude of daily moisture variations. It was possible, by the combined effect of ventilation and wood as buffering material, to keep the indoor RH at a very stable level. (author)

  8. Effect of humidity and temperature on the survival of Listeria monocytogenes on surfaces.

    Science.gov (United States)

    Redfern, J; Verran, J

    2017-04-01

    Listeria monocytogenes is a pathogenic bacterium, with human disease and infection linked to dairy products, seafood, ready-to-eat meat and raw & undercooked meats. Stainless steel is the most common food preparation surface and therefore, it is important to understand how food storage conditions such as surface materials, temperature and relative humidity can affect survival of L. monocytogenes. In this study, survival of L. monocytogenes on stainless steel was investigated at three temperatures (4, 10 and 21°C), each approx. 11, 50 and 85% humidity. Results indicate that the lower the temperature, the more cells were recovered in all three humidity environments, while medium humidity enhances survival, irrespective of temperature. Lower humidity decreases recovery at all temperatures. These data support the guidance noted above that humidity control is important, and that lower humidity environments are less likely to support retention of viable L. monocytogenes on a stainless steel surface. Understanding survival of potential food-borne pathogens is essential for the safe production and preparation of food. While it has long been 'common knowledge' that relative humidity can affect the growth and survival of micro-organisms, this study systematically describes the survival of L. monocytogenes on stainless steel under varying humidity and temperatures for the first time. The outcomes from this paper will allow those involved with food manufacture and preparation to make informed judgement on environmental conditions relating to humidity control, which is lacking in the food standards guidelines. © 2017 The Society for Applied Microbiology.

  9. Effect of Relative Humidity on the Tribological Properties of Self-Lubricating H3BO3 Films Formed on the Surface of Steel Suitable for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    E. Hernández-Sanchez

    2015-01-01

    Full Text Available The effect of environmental humidity on the self-lubricating properties of a thin film of boric acid (H3BO3 was evaluated. H3BO4 films were successfully formed on the surface of AISI 316L steel. The study was conducted on AISI 316L steel because of its use in biomedical applications. First, the samples were exposed to boriding to generate a continuous surface layer of iron borides. The samples were then exposed to a short annealing process (SAP at 1023 K for 5 min and cooled to room temperature while controlling the relative humidity (RH. Five different RH conditions were tested. The purpose of SAP was to promote the formation of a surface film of boric acid from the boron atoms present in the iron boride layers. The presence of the boric acid at the surface of the borided layer was confirmed by Raman spectroscopy and X-ray diffraction (XRD. The self-lubricating capability of the films was demonstrated using the pin-on-disk technique. The influence of RH was reflected by the friction coefficient (FC, as the samples cooled with 20% of RH exhibited FC values of 0.16, whereas the samples cooled at 60% RH showed FC values of 0.02.

  10. Repeatability and Reversibility of the Humidity Sensor Based on Photonic Crystal Fiber Interferometer

    Science.gov (United States)

    Hindal, S. S.; Taher, H. J.

    2018-05-01

    The RH sensor operation based on water vapor adsorption and desorption at the silica-air interface within the PCF. Sensor fabrication is simple; it includes splicing and cleaving the PCF with SMF only. PCF (LMA-10) with a certain length spliced to SMF (Corning-28). The PCFI spectrum exhibits good sensitivity to the variations of humidity. The PCFI response is observed for range of relative humidity values from (27% RH to 85% RH), the interference peaks position is found to be shifted to longer wavelength as the humidity increases. In this work, a 6cm length of PCFs is used, and it shows a sensitivity of (2.41pm / %RH), good repeatability, and reversible in nature. This humidity sensor has distinguished features as that the sensor does not require the use of a hygroscopic material, robust, compact size, immunity to electromagnetic interference, and it has potential applications for high humidity environments.

  11. Fabrication and Evaluation of a Graphene Oxide-Based Capacitive Humidity Sensor

    Directory of Open Access Journals (Sweden)

    Jinfeng Feng

    2016-03-01

    Full Text Available In this study, a CMOS compatible capacitive humidity sensor structure was designed and fabricated on a 200 mm CMOS BEOL Line. A top Al interconnect layer was used as an electrode with a comb/serpent structure, and graphene oxide (GO was used as sensing material. XRD analysis was done which shows that GO sensing material has a strong and sharp (002 peak at about 10.278°, whereas graphite has (002 peak at about 26°. Device level CV and IV curves were measured in mini-environments at different relative humidity (RH level, and saturated salt solutions were used to build these mini-environments. To evaluate the potential value of GO material in humidity sensor applications, a prototype humidity sensor was designed and fabricated by integrating the sensor with a dedicated readout ASIC and display/calibration module. Measurements in different mini-environments show that the GO-based humidity sensor has higher sensitivity, faster recovery time and good linearity performance. Compared with a standard humidity sensor, the measured RH data of our prototype humidity sensor can match well that of the standard product.

  12. Fabrication and Evaluation of a Graphene Oxide-Based Capacitive Humidity Sensor.

    Science.gov (United States)

    Feng, Jinfeng; Kang, Xiaoxu; Zuo, Qingyun; Yuan, Chao; Wang, Weijun; Zhao, Yuhang; Zhu, Limin; Lu, Hanwei; Chen, Juying

    2016-03-01

    In this study, a CMOS compatible capacitive humidity sensor structure was designed and fabricated on a 200 mm CMOS BEOL Line. A top Al interconnect layer was used as an electrode with a comb/serpent structure, and graphene oxide (GO) was used as sensing material. XRD analysis was done which shows that GO sensing material has a strong and sharp (002) peak at about 10.278°, whereas graphite has (002) peak at about 26°. Device level CV and IV curves were measured in mini-environments at different relative humidity (RH) level, and saturated salt solutions were used to build these mini-environments. To evaluate the potential value of GO material in humidity sensor applications, a prototype humidity sensor was designed and fabricated by integrating the sensor with a dedicated readout ASIC and display/calibration module. Measurements in different mini-environments show that the GO-based humidity sensor has higher sensitivity, faster recovery time and good linearity performance. Compared with a standard humidity sensor, the measured RH data of our prototype humidity sensor can match well that of the standard product.

  13. Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

    Directory of Open Access Journals (Sweden)

    Tero Jalkanen

    2015-01-01

    Full Text Available A roll-to-roll compatible fabrication process of porous silicon (pSi based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

  14. Efficiency of oxygen: absorbing sachets in different relative humidities and temperatures Eficiência de absorvedores de oxigênio sob diferentes umidades relativas e temperaturas

    Directory of Open Access Journals (Sweden)

    Renato Souza Cruz

    2007-12-01

    Full Text Available The main objective of this work was to evaluate the efficiency of oxygen - absorbing sachets at relative humidity of 75%, 80% and 85% and different temperatures, 10±2 ºC and 25±2 ºC. The experiment consisted in determining the O2 absorption under these conditions. A sachet was placed in desiccators with an internal air homogenization system. Aliquots of air were removed at pre-established time intervals and analyzed for oxygen content. The results showed that oxygen absorption by the sachet increased as the relative humidity increased for both temperature. Therefore the oxygen - absorbing sachets were most active under 25±2ºC and 85% relative humidity. At ambient condition (25±2ºC/75%RH the rate of oxygen absorbed was 50 mL/day and 18,5 mL/day for 10±2ºC. It was used a totally casualized design with three replicates.O objetivo principal deste trabalho foi avaliar a eficiência de sachês absorvedores de oxigênio a 75%, 80% e 85% de umidade relativa e diferentes temperaturas, 10±2 ºC e 25±2 ºC. O experimento consiste em determinar a absorção de O2 sob essas condições. Um sachê foi colocado dentro de um dessecador contendo um sistema de homogeneização do ar interno. Alíquotas de ar são retiradas dos dessecadores em intervalos de tempos pré-estabelecido e seu conteúdo de oxigênio analisado. Os resultados mostraram que a absorção de oxigênio pelos saches aumentaram com o aumento da temperatura para ambas as temperaturas. No entanto, os sachês mostraram uma maior eficiência para 85% de umidade relativa e 25±2ºC de temperatura. Na condição ambiente (25±2ºC/75%RH, a taxa de absorção dos sachês foi de 50 mL/dia e 18,5 mL/dia para 10±2ºC. O experimento foi conduzido com delineamento experimental inteiramente casualizado, com três repetições.

  15. Absolute humidity and the human nose: A reanalysis of climate zones and their influence on nasal form and function.

    Science.gov (United States)

    Maddux, Scott D; Yokley, Todd R; Svoma, Bohumil M; Franciscus, Robert G

    2016-10-01

    Investigations into the selective role of climate on human nasal variation commonly divide climates into four broad adaptive zones (hot-dry, hot-wet, cold-dry, and cold-wet) based on temperature and relative humidity. Yet, absolute humidity-not relative humidity-is physiologically more important during respiration. Here, we investigate the global distribution of absolute humidity to better clarify ecogeographic demands on nasal physiology. We use monthly observations from the Climatic Research Unit Timeseries 3 (CRU TS3) database to construct global maps of average annual temperature, relative humidity and absolute humidity. Further, using data collected by Thomson and Buxton (1923) for over 15,000 globally-distributed individuals, we calculate the actual amount of heat and water that must be transferred to inspired air in different climatic regimes to maintain homeostasis, and investigate the influence of these factors on the nasal index. Our results show that absolute humidity, like temperature, generally decreases with latitude. Furthermore, our results demonstrate that environments typically characterized as "cold-wet" actually exhibit low absolute humidities, with values virtually identical to cold-dry environments and significantly lower than hot-wet and even hot-dry environments. Our results also indicate that strong associations between the nasal index and absolute humidity are, potentially erroneously, predicated on individuals from hot-dry environments possessing intermediate (mesorrhine) nasal indices. We suggest that differentially allocating populations to cold-dry or cold-wet climates is unlikely to reflect different selective pressures on respiratory physiology and nasal morphology-it is cold-dry, and to a lesser degree hot-dry environments, that stress respiratory function. Our study also supports assertions that demands for inspiratory modification are reduced in hot-wet environments, and that expiratory heat elimination for thermoregulation is a

  16. Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity.

    Science.gov (United States)

    Lee, Shih-Wei; Chen, Jyh-Chien; Wu, Jin-An; Chen, Kuei-Hsien

    2017-03-22

    Novel sulfonated poly(ether sulfone) copolymers (S4PH-x-PSs) based on a new aromatic diol containing four phenyl substituents at the 2, 2', 6, and 6' positions of 4,4'-diphenyl ether were synthesized. Sulfonation was found to occur exclusively on the 4 position of phenyl substituents by NMR spectroscopy. The ion exchange capacity (IEC) values can be controlled by adjusting the mole percent (x in S4PH-x-PS) of the new diol. The fully hydrated sulfonated poly(ether sulfone) copolymers had good proton conductivity in the range 0.004-0.110 S/cm at room temperature. The surface morphology of S4PH-x-PSs and Nafion 212 was investigated by atomic force microscopy (tapping-mode) and related to the percolation limit and proton conductivity. Single H 2 /O 2 fuel cell based on S4PH-40-PS loaded with 0.25 mg/cm 2 catalyst (Pt/C) exhibited a peak power density of 462.6 mW/cm 2 , which was close to that of Nafion 212 (533.5 mW/cm 2 ) at 80 °C with 80% RH. Furthermore, fuel cell performance of S4PH-35-PS with various relative humidity was investigated. It was confirmed from polarization curves that the fuel cell performance of S4PH-35-PS was not as high as that of Nafion 212 under fully hydrated state due to higher interfacial resistance between S4PH-35-PS and electrodes. While under low relative humidity (53% RH) at 80 °C, fuel cells based on S4PH-35-PS showed higher peak power density (234.9 mW/cm 2 ) than that (214.0 mW/cm 2 ) of Nafion 212.

  17. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Evelise G.; Oliveira, Arno Heeren de, E-mail: evelise.lara@gmail.com, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Rocha, Zildete; Rios, Francisco Javier, E-mail: rochaz@cdtn.br, E-mail: javier@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The {sup 226}Ra, {sup 232}Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The {sup 226}Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to {sup 232}Th and U content. The soil permeability is 5.0 x 10{sup -12}, which is considered average. The {sup 226}Ra (22.2 ± 0.3 Bq.m{sup -3}); U content (73.4 ± 3.6 Bq.kg{sup -1}) and {sup 232}Th content (55.3 ± 4.0 Bq.kg{sup -1}) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg{sup -1}) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m{sup -3}) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m{sup -3}). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  18. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    International Nuclear Information System (INIS)

    Lara, Evelise G.; Oliveira, Arno Heeren de

    2015-01-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The 226 Ra, 232 Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The 226 Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to 232 Th and U content. The soil permeability is 5.0 x 10 -12 , which is considered average. The 226 Ra (22.2 ± 0.3 Bq.m -3 ); U content (73.4 ± 3.6 Bq.kg -1 ) and 232 Th content (55.3 ± 4.0 Bq.kg -1 ) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg -1 ) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m -3 ) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m -3 ). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  19. Thermal Comfort and Optimum Humidity Part 1

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  20. Thermal Comfort and Optimum Humidity Part 2

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  1. A nafion coated capacitive humidity sensor on a flexible PET substrate

    KAUST Repository

    Sapsanis, Christos

    2017-03-07

    This paper reports a simple and low-cost technique for fabricating low-power capacitive humidity sensors without the use of a cleanroom environment. A maskless laser engraving system was utilized to fabricate two different gold electrode structures, interdigitated electrodes and Hilbert\\'s fifth-order fractal. The capacitive structures were implemented on a flexible PET substrate. The usage of Nafion, a well-known polymer for its hydrophilic properties as a sensing film, was attempted on the PET and outperformed the current efforts in flexible substrates. Its humidity sensing properties were evaluated in an automated gas setup with a relative humidity (RH %) ranging from 15% to 95 %.

  2. A nafion coated capacitive humidity sensor on a flexible PET substrate

    KAUST Repository

    Sapsanis, Christos; Buttner, Ulrich; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Eddaoudi, Mohamed; Salama, Khaled N.

    2017-01-01

    This paper reports a simple and low-cost technique for fabricating low-power capacitive humidity sensors without the use of a cleanroom environment. A maskless laser engraving system was utilized to fabricate two different gold electrode structures, interdigitated electrodes and Hilbert's fifth-order fractal. The capacitive structures were implemented on a flexible PET substrate. The usage of Nafion, a well-known polymer for its hydrophilic properties as a sensing film, was attempted on the PET and outperformed the current efforts in flexible substrates. Its humidity sensing properties were evaluated in an automated gas setup with a relative humidity (RH %) ranging from 15% to 95 %.

  3. Improved running performance in hot humid conditions following whole body precooling.

    Science.gov (United States)

    Booth, J; Marino, F; Ward, J J

    1997-07-01

    On two separate occasions, eight subjects controlled speed to run the greatest distance possible in 30 min in a hot, humid environment (ambient temperature 32 degrees C, relative humidity 60%). For the experimental test (precooling), exercise was preceeded by cold-water immersion. Precooling increased the distance run by 304 +/- 166 m (P body temperature decreased from 36.5 +/- 0.1 degrees C to 33.8 +/- 0.2 degrees C following precooling (P body sweating are not different between tests. In conclusion, water immersion precooling increased exercise endurance in hot, humid conditions with an enhanced rate of heat storage and decreased thermoregulatory strain.

  4. Spaceborne profiling of atmospheric temperature and particle extinction with pure rotational Raman lidar and of relative humidity in combination with differential absorption lidar: performance simulations

    International Nuclear Information System (INIS)

    Di Girolamo, Paolo; Behrendt, Andreas; Wulfmeyer, Volker

    2006-01-01

    The performance of a spaceborne temperature lidar based on the pure rotational Raman (RR) technique in the UV has been simulated. Results show that such a system deployed onboard a low-Earth-orbit satellite would provide global-scale clear-sky temperature measurements in the troposphere and lower stratosphere with precisions that satisfy World Meteorological Organization (WMO) threshold observational requirements for numerical weather prediction and climate research applications. Furthermore, nighttime temperature measurements would still be within the WMO threshold observational requirements in the presence of several cloud structures. The performance of aerosol extinction measurements from space, which can be carried out simultaneously with temperature measurements by RR lidar, is also assessed. Furthermore, we discuss simulations of relative humidity measurements from space obtained from RR temperature measurements and water-vapor data measured with the differential absorption lidar (DIAL) technique

  5. The influence of temperature, relative humidity and rainfall on the occurrence of the Pine Wood Nematode in Góis Council, Portugal

    Science.gov (United States)

    Costa, M. E. G.; Rodrigues, M. A.

    2012-04-01

    In this work, we propose to investigate the influence of the pine wood nematode in the species pinus pinaster in Góis council and the way it affects the economic activity in this region. In order to do that we are going to analyse the influence of temperature, relative humidity and rainfall in the development of the vector insect of the pine wood nematode. In a first stage we are going to do a homogenisation of the series of temperature and rainfall, since they present a significant lack of data. For that we have chosen a reference station that allows us to determine the correlation coefficient to eliminate the lacks that are present in the other series. After that we are going to do the correlation with the number of nematode episodes that occurred and evaluate the area affected for a single year.

  6. Design and Development of a Relative Humidity and Room Temperature Measurement System with On Line Data Logging Feature for Monitoring the Fermentation Room of Tea Factory

    Directory of Open Access Journals (Sweden)

    Utpal SARMA

    2011-12-01

    Full Text Available The design and development of a Relative Humidity (RH and Room Temperature (RT monitoring system with on line data logging feature for monitoring fermentation room of a tea factory is presented in this paper. A capacitive RH sensor with on chip signal conditioner is taken as RH sensor and a temperature to digital converter (TDC is used for ambient temperature monitoring. An 8051 core microcontroller is the heart of the whole system which reads the digital equivalent of RH data with the help of a 12-bit Analog to Digital (A/D converter and synchronize TDC to get the ambient temperature. The online data logging is achieved with the help of RS-232C communication. Field performance is also studied by installing it in the fermentation room of a tea factory.

  7. Measurements of VOC/SVOC emission factors from burning incenses in an environmental test chamber: influence of temperature, relative humidity, and air exchange rate.

    Science.gov (United States)

    Manoukian, A; Buiron, D; Temime-Roussel, B; Wortham, H; Quivet, E

    2016-04-01

    This study investigates the influence of three environmental indoor parameters (i.e., temperature, relative humidity, and air exchange rate) on the emission of 13 volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) during incense burning. Experiments have been carried out using an environmental test chamber. Statistical results from a classical two-level full factorial design highlight the predominant effect of ventilation on emission factors. The higher the ventilation, the higher the emission factor. Moreover, thanks to these results, an estimation of the concentration range for the compounds under study can be calculated and allows a quick look of indoor pollution induced by incense combustion. Carcinogenic substances (i.e., benzene, benzo(a)pyrene, and formaldehyde) produced from the incense combustion would be predicted in typical living indoors conditions to reach instantaneous concentration levels close to or higher than air quality exposure threshold values.

  8. The relationship between aerosol backscatter coefficient and atmospheric relative humidity in an urban area over Athens, Greece, using Raman lidar and radiosonde data

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Papayannis, A.; Mamouri, R.E.

    2011-01-01

    In this article a statistical assessment concerning the relationship between the aerosol backscatter coefficient (βaer) and the relative humidity (RH) in the lower andmiddle troposphere, over Athens (Greece), is presented. For the purpose of this study, correlative radiosonde and aerosol...... (355 nm) and visible (532 nm) wavelengths. The correlation coefficient (R) of the vertical profiles of the RH against the backscatter coefficient of aerosols was investigated in altitudes within the free troposphere (0–6000 m). The altitude range was divided into three areas: 0 m up to the top...... was higher than during the cold period (autumn–winter). Regarding the correlation coefficient (R), low (0–0.5) and medium (0.5–0.8) R values were mostly observed during the warmmonths of the year. For the aerosols originating fromthe Balkan area the highest correlation was observed at both wavelengths (R = 0...

  9. The importance of relative humidity and trophic resources in governing ecological niche of the invasive carabid beetle Merizodus soledadinus in the Kerguelen archipelago.

    Science.gov (United States)

    Ouisse, Tiphaine; Bonte, Dries; Lebouvier, Marc; Hendrickx, Frederik; Renault, David

    Comprehensive studies to identify species-specific drivers of survival to environmental stress, reproduction, growth, and recruitment are vital to gaining a better understanding of the main ecological factors shaping species habitat distribution and dispersal routes. The present study performed a field-based assessment of habitat distribution in the invasive carabid beetle Merizodus soledadinus for the Kerguelen archipelago. The results emphasised humid habitats as a key element of the insect's realised niche. In addition, insects faced food and water stress during dispersal events. We evaluated quantitatively how water availability and trophic resources governed the spatial distribution of this invasive predatory insect at Îles Kerguelen. Food and water stress survival durations [in 100%, 70%, and 30% relative humidity (RH) conditions] and changes in a set of primary metabolic compounds (metabolomics) were determined. Adult M. soledadinus supplied with water ad libitum were highly tolerant to prolonged starvation (LT 50 =51.7±6.2d). However, food-deprived insect survival decreased rapidly in moderate (70% RH, LT 50 =30.37±1.39h) and low (30% RH, LT 50 =13.03±0.48h) RH conditions. Consistently, body water content decreased rapidly in insects exposed to 70% and 30% RH. Metabolic variation evidenced the effects of food deprivation in control insects (exposed to 100% RH), which exhibited a progressive decline of most glycolytic sugars and tricarboxylic acid cycle intermediates. Most metabolite levels were elevated levels during the first few hours of exposure to 30% and 70% RH. Augmented alanine and lactate levels suggested a shift to anaerobic metabolism. Simultaneously, peaks in threonine and glycolytic sugars pointed to metabolic disruption and a progressive physiological breakdown in dehydrating individuals. Overall, the results of our study indicate that the geographic distribution of M. soledadinus populations is highly dependent on habitat RH and water

  10. Study on the Correlation between Humidity and Material Strains in Separable Micro Humidity Sensor Design

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Chang

    2017-05-01

    Full Text Available Incidents of injuries caused by tiles falling from building exterior walls are frequently reported in Taiwan. Humidity is an influential factor in tile deterioration but it is more difficult to measure the humidity inside a building structure than the humidity in an indoor environment. Therefore, a separable microsensor was developed in this study to measure the humidity of the cement mortar layer with a thickness of 1.5–2 cm inside the external wall of a building. 3D printing technology is used to produce an encapsulation box that can protect the sensor from damage caused by the concrete and cement mortar. The sensor is proven in this study to be capable of measuring temperature and humidity simultaneously and the measurement results are then used to analyze the influence of humidity on external wall tile deterioration.

  11. Effective Learning Environments in Relation to Different Learning Theories

    OpenAIRE

    Guney, Ali; Al, Selda

    2012-01-01

    There are diverse learning theories which explain learning processes which are discussed within this paper, through cognitive structure of learning process. Learning environments are usually described in terms of pedagogical philosophy, curriculum design and social climate. There have been only just a few studies about how physical environment is related to learning process. Many researchers generally consider teaching and learning issues as if independent from physical environment, whereas p...

  12. NATURE OF BUSINESS ENVIRONMENT IN INTERNATIONAL ECONOMIC RELATIONS

    Directory of Open Access Journals (Sweden)

    Zlatka Kushelieva

    2017-06-01

    Full Text Available The role and importance of the factors influencing the business environment in the economic relations of enterprises in national and international aspect are discussed. Global interdependencies have been explored and results have been drawn on the impact of international political and economic changes on the business environment of national and supranational companies.

  13. Morbidity is related to a green living environment.

    NARCIS (Netherlands)

    Maas, J.; Verheij, R.A.; Vries, S. de; Spreeuwenberg, P.; Groenewegen, P.P.; Schellevis, F.G.

    2009-01-01

    Background: Due to increasing urbanisation people face the prospect of living in environments with few green spaces. There is increasing evidence for a positive relation between green space in people's living environment and self-reported indicators of physical and mental health. This study

  14. Humidity level In psychrometric processes

    International Nuclear Information System (INIS)

    Mojsovski, Filip

    2008-01-01

    When a thermal engineer needs to control, rather than merely moderate humidity, he must focus on the moisture level as a separate variable - not simply an addition of temperature control. Controlling humidity generally demands a correct psychrometric approach dedicated to that purpose [1].Analysis of the humidity level in psychrometric thermal processes leads to relevant data for theory and practice [2]. This paper presents: (1) the summer climatic curve for the Skopje region, (2) selected results of investigation on farm dryers made outside laboratories. The first purpose of such activity was to examine relations between weather conditions and drying conditions. The estimation of weather condition for the warmest season of the year was realized by a summer climatic curve. In the science of drying, basic drying conditions are temperature, relative humidity and velocity of air, thickness of dried product and dryer construction. The second purpose was to realize correct prediction of drying rates for various psychrometrics drying processes and local products. Test runs with the dryer were carried out over a period of 24 h, using fruits and vegetables as experimental material. Air flow rate through the dryer of 150 m3/h, overall drying rate of 0.04 kg/h and air temperature of 65 oC were reached. Three types of solar dryers, were exploited in the research.

  15. PENGARUH SUHU DAN KELEMBABAN UDARA TERHADAP PERUBAHAN MUTU TABLET EFFERVESCEN SARI BUAH SELAMA PENYIMPANAN [Influence of Temperature and Relative Humidity on the Quality of Fruit Juice Effervescent Tablet During Storage

    Directory of Open Access Journals (Sweden)

    Ansar

    2011-06-01

    Full Text Available The aim of this research was to study the influence of temperature and relative humidity on the quality of the fruit juice effervescent tablet. Sample of the passion fruit effervescent tablet was prepared from passion fruit granular, aspartame, polyetilene glycol, citric acid, and sodium bicarbonate. Variable analyzed was dissolution rate of the tablet during storage. The results indicated that temperature and humidity significantly affect dissolution rate of the fruit juice effervescent tablet. The reason for the decrease in dissolution rate was because at high storage temperature (35oC, sodium bicarbonate was not stable. The bicarbonate amount gradually decreased because it reacted with citric acid. Consequently, when the tablet was dissolved, the reaction between sodium bicarbonate and citric acid was slow. At high relative humidity (85.5% of storage, the reaction occurred prior to the dissolution due to moisture intake.

  16. Room temperature humidity sensor based on polyaniline-tungsten disulfide composite

    Science.gov (United States)

    Manjunatha, S.; Chethan, B.; Ravikiran, Y. T.; Machappa, T.

    2018-05-01

    Polyaniline-tungsten disulfide (PANI-WS2) composite was synthesized using in situ polymerization technique by adding finely grinded powder of WS2 during the polymerization of aniline. Field emission scanning electron microscopy (FESEM) images showed the granular morphology with porous nature. Energy dispersive X-ray spectroscopy (EDX) confirmed the presence of carbon, nitrogen, chlorine of PANI, tungsten and sulfur elements of WS2. Humidity sensing property of the composite was investigated by plotting change in its resistance with different relative humidity environments ranging from 10 to 97% RH. Decrease in resistance of the composite was observed with increase in relative humidity. Maximum sensing response of the composite was found to be 88.46%. Response and recovery times of the composite at 97%RH were fair enough to fabricate a sensor based on it. Stability of the composite with respect to the humidity sensing behavior was observed to be unchanged even after two months.

  17. Humidity Detection Using Metal Organic Framework Coated on QCM

    KAUST Repository

    Kosuru, Lakshmoji; Bouchaala, Adam M.; Jaber, Nizar; Younis, Mohammad I.

    2016-01-01

    of a quartz crystal microbalance. The resonance frequencies of these sensors with varying relative humidity (RH) from 22% RH to 69% RH are measured using impedance analysis method. The sensitivity, humidity hysteresis, response, and recovery times

  18. Aerosol optical properties in the southeastern United States in summer – Part 2: Sensitivity of aerosol optical depth to relative humidity and aerosol parameters

    Directory of Open Access Journals (Sweden)

    C. A. Brock

    2016-04-01

    Full Text Available Aircraft observations of meteorological, trace gas, and aerosol properties were made between May and September 2013 in the southeastern United States (US. Regionally representative aggregate vertical profiles of median and interdecile ranges of the measured parameters were constructed from 37 individual aircraft profiles made in the afternoon when a well-mixed boundary layer with typical fair-weather cumulus was present (Wagner et al., 2015. We use these 0–4 km aggregate profiles and a simple model to calculate the sensitivity of aerosol optical depth (AOD to changes in dry aerosol mass, relative humidity, mixed-layer height, the central diameter and width of the particle size distribution, hygroscopicity, and dry and wet refractive index, while holding the other parameters constant. The calculated sensitivity is a result of both the intrinsic sensitivity and the observed range of variation in these parameters. These observationally based sensitivity studies indicate that the relationship between AOD and dry aerosol mass in these conditions in the southeastern US can be highly variable and is especially sensitive to relative humidity (RH. For example, calculated AOD ranged from 0.137 to 0.305 as the RH was varied between the 10th and 90th percentile profiles with dry aerosol mass held constant. Calculated AOD was somewhat less sensitive to aerosol hygroscopicity, mean size, and geometric standard deviation, σg. However, some chemistry–climate models prescribe values of σg substantially larger than we or others observe, leading to potential high biases in model-calculated AOD of  ∼  25 %. Finally, AOD was least sensitive to observed variations in dry and wet aerosol refractive index and to changes in the height of the well-mixed surface layer. We expect these findings to be applicable to other moderately polluted and background continental air masses in which an accumulation mode between 0.1–0.5 µm diameter dominates

  19. Measuring OVOCs and VOCs by PTR-MS in an urban roadside microenvironment of Hong Kong: relative humidity and temperature dependence, and field intercomparisons

    Science.gov (United States)

    Cui, Long; Zhang, Zhou; Huang, Yu; Lee, Shun Cheng; Blake, Donald Ray; Ho, Kin Fai; Wang, Bei; Gao, Yuan; Wang, Xin Ming; Kwok Keung Louie, Peter

    2016-12-01

    Volatile organic compound (VOC) control is an important issue of air quality management in Hong Kong because ozone formation is generally VOC limited. Several oxygenated volatile organic compound (OVOC) and VOC measurement techniques - namely, (1) offline 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling followed by high-performance liquid chromatography (HPLC) analysis; (2) online gas chromatography (GC) with flame ionization detection (FID); and (3) offline canister sampling followed by GC with mass spectrometer detection (MSD), FID, and electron capture detection (ECD) - were applied during this study. For the first time, the proton transfer reaction-mass spectrometry (PTR-MS) technique was also introduced to measured OVOCs and VOCs in an urban roadside area of Hong Kong. The integrated effect of ambient relative humidity (RH) and temperature (T) on formaldehyde measurements by PTR-MS was explored in this study. A Poly 2-D regression was found to be the best nonlinear surface simulation (r = 0.97) of the experimental reaction rate coefficient ratio, ambient RH, and T for formaldehyde measurement. This correction method was found to be better than correcting formaldehyde concentrations directly via the absolute humidity of inlet sample, based on a 2-year field sampling campaign at Mong Kok (MK) in Hong Kong. For OVOC species, formaldehyde, acetaldehyde, acetone, and MEK showed good agreements between PTR-MS and DNPH-HPLC with slopes of 1.00, 1.10, 0.76, and 0.88, respectively, and correlation coefficients of 0.79, 0.75, 0.60, and 0.93, respectively. Overall, fair agreements were found between PTR-MS and online GC-FID for benzene (slope = 1.23, r = 0.95), toluene (slope = 1.01, r = 0.96) and C2-benzenes (slope = 1.02, r = 0.96) after correcting benzene and C2-benzenes levels which could be affected by fragments formed from ethylbenzene. For the intercomparisons between PTR-MS and offline canister measurements by GC-MSD/FID/ECD, benzene showed good agreement

  20. Floral humidity as a reliable sensory cue for profitability assessment by nectar-foraging hawkmoths

    Science.gov (United States)

    von Arx, Martin; Goyret, Joaquín; Davidowitz, Goggy; Raguso, Robert A.

    2012-01-01

    Most research on plant–pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue—transient humidity gradients—using the night blooming flowers of Oenothera cespitosa (Onagraceae). The headspace of newly opened flowers reaches levels of about 4% above ambient relative humidity due to additive evapotranspirational water loss through petals and water-saturated air from the nectar tube. Floral humidity plumes differ from ambient levels only during the first 30 min after anthesis (before nectar is depleted in wild populations), whereas other floral traits (scent, shape, and color) persist for 12–24 h. Manipulative experiments indicated that floral humidity gradients are mechanistically linked to nectar volume and therefore contain information about energy rewards to floral visitors. Behavioral assays with Hyles lineata (Sphingidae) and artificial flowers with appropriate humidity gradients suggest that these hawkmoth pollinators distinguish between subtle differences in relative humidity when other floral cues are held constant. Moths consistently approached and probed flowers with elevated humidity over those with ambient humidity levels. Because floral humidity gradients are largely produced by the evaporation of nectar itself, they represent condition-informative cues that facilitate remote sensing of floral profitability by discriminating foragers. In a xeric environment, this level of honest communication should be adaptive when plant reproductive success is pollinator limited, due to intense competition for the attention of a specialized pollinator. PMID:22645365

  1. Floral humidity as a reliable sensory cue for profitability assessment by nectar-foraging hawkmoths.

    Science.gov (United States)

    von Arx, Martin; Goyret, Joaquín; Davidowitz, Goggy; Raguso, Robert A

    2012-06-12

    Most research on plant-pollinator communication has focused on sensory and behavioral responses to relatively static cues. Floral rewards such as nectar, however, are dynamic, and foraging animals will increase their energetic profit if they can make use of floral cues that more accurately indicate nectar availability. Here we document such a cue--transient humidity gradients--using the night blooming flowers of Oenothera cespitosa (Onagraceae). The headspace of newly opened flowers reaches levels of about 4% above ambient relative humidity due to additive evapotranspirational water loss through petals and water-saturated air from the nectar tube. Floral humidity plumes differ from ambient levels only during the first 30 min after anthesis (before nectar is depleted in wild populations), whereas other floral traits (scent, shape, and color) persist for 12-24 h. Manipulative experiments indicated that floral humidity gradients are mechanistically linked to nectar volume and therefore contain information about energy rewards to floral visitors. Behavioral assays with Hyles lineata (Sphingidae) and artificial flowers with appropriate humidity gradients suggest that these hawkmoth pollinators distinguish between subtle differences in relative humidity when other floral cues are held constant. Moths consistently approached and probed flowers with elevated humidity over those with ambient humidity levels. Because floral humidity gradients are largely produced by the evaporation of nectar itself, they represent condition-informative cues that facilitate remote sensing of floral profitability by discriminating foragers. In a xeric environment, this level of honest communication should be adaptive when plant reproductive success is pollinator limited, due to intense competition for the attention of a specialized pollinator.

  2. Analysis of proton exchange membrane fuel cell polarization losses at elevated temperature 120 {sup o}C and reduced relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hui [Department of Chemical Engineering, University of Connecticut, Storrs, CT (United States)]. E-mail: huixu@lanl.gov; Kunz, H. Russell [Department of Chemical Engineering, University of Connecticut, Storrs, CT (United States); Fenton, James M. [Florida Solar Energy Center, University of Central Florida, Cocoa, FL (United States)

    2007-03-01

    Polarization losses of proton exchange membrane (PEM) fuel cells at 120 {sup o}C and reduced relative humidity (RH) were analyzed. Reduced RH affects membrane and electrode ionic resistance, catalytic activity and oxygen transport. For a cell made of Nafion (registered) 112 membrane and electrodes that have 35 wt.% Nafion (registered) and 0.3 mg/cm{sup 2} platinum supported on carbon, membrane resistance at 20%RH was 0.407 {omega} cm{sup 2} and electrode resistance 0.203 {omega} cm{sup 2}, significantly higher than 0.092 and 0.041 {omega} cm{sup 2} at 100%RH, respectively. In the kinetically controlled region, 20%RH resulted in 96 mV more cathode activation loss than 100%RH. Compared to 100%, 20%RH also produced significant oxygen transport loss across the ionomer film in the electrode, 105 mV at 600 mA/cm{sup 2}. The significant increase in polarization losses at elevated temperature and reduced RH indicates the extreme importance of designing electrodes for high temperature PEM fuel cells since membrane development has always taken most emphasis.

  3. Photocatalysis of gaseous trichloroethylene (TCE) over TiO2: The effect of oxygen and relative humidity on the generation of dichloroacetyl chloride (DCAC) and phosgene

    International Nuclear Information System (INIS)

    Ou, H.-H.; Lo, S.-L.

    2007-01-01

    Batch photocatalytic degradation of 80 ± 2.5 ppmV trichloroethylene (TCE) was conducted to investigate the effect of the oxygen and relative humidity (RH) on the formation of the dichloroacetyl chloride (DCAC) and phosgene. Based on the simultaneous ordinary differential equations (ODEs), the reaction rate constants of TCE ((2.31 ± 0.28) ∼ (9.41 ± 0.63) x 10 -2 min -1 ) are generally larger than that of DCAC ((0.94 ± 1.25) ∼ (9.35 ± 1.71) x 10 -3 min -1 ) by approximate one order. The phenomenon indicates the degradation potential of TCE is superior to that of DCAC. DCAC appreciably delivers the same degradation behavior with TCE that means there exists an optimum RH and oxygen concentration for photocatalysis of TCE and DCAC. At the time the peak yield of DCAC appears, the conversion ratio based on the carbon atom from TCE to DCAC is within the range of 30-83% suggesting that the DCAC generation is significantly attributed to TCE degradation. Regarding the phosgene formation, the increasing oxygen amount leads to the inhibitory effect on the phosgene yield which fall within the range of 5-15%. The formation mechanism of phosgene was also inferred that the Cl atoms attacking the C-C bond of DCAC results to the generation of phosgene rather than directly from the TCE destruction

  4. Photocatalysis of gaseous trichloroethylene (TCE) over TiO2: the effect of oxygen and relative humidity on the generation of dichloroacetyl chloride (DCAC) and phosgene.

    Science.gov (United States)

    Ou, Hsin-Hung; Lo, Shang-Lien

    2007-07-19

    Batch photocatalytic degradation of 80+/-2.5 ppm V trichloroethylene (TCE) was conducted to investigate the effect of the oxygen and relative humidity (RH) on the formation of the dichloroacetyl chloride (DCAC) and phosgene. Based on the simultaneous ordinary differential equations (ODEs), the reaction rate constants of TCE ((2.31+/-0.28) approximately (9.41+/-0.63)x10(-2) min(-1)) are generally larger than that of DCAC ((0.94+/-1.25) approximately (9.35+/-1.71)x10(-3) min(-1)) by approximate one order. The phenomenon indicates the degradation potential of TCE is superior to that of DCAC. DCAC appreciably delivers the same degradation behavior with TCE that means there exists an optimum RH and oxygen concentration for photocatalysis of TCE and DCAC. At the time the peak yield of DCAC appears, the conversion ratio based on the carbon atom from TCE to DCAC is within the range of 30-83% suggesting that the DCAC generation is significantly attributed to TCE degradation. Regarding the phosgene formation, the increasing oxygen amount leads to the inhibitory effect on the phosgene yield which fall within the range of 5-15%. The formation mechanism of phosgene was also inferred that the Cl atoms attacking the C-C bond of DCAC results to the generation of phosgene rather than directly from the TCE destruction.

  5. Method for determining the footprint area of air temperature and relative humidity - doi: 10.4025/actascitechnol.v35i2.11791

    Directory of Open Access Journals (Sweden)

    Elis Dener Lima Alves

    2013-04-01

    Full Text Available Despite the numerous studies in the area of urban climatology, there is still a relevant gap in this area corresponding to the demarcation of the footprint area on a variable. Various authors arbitrarily delimit this area without a prior study, which leads to significant errors in the results. In recent years, a variety of models to estimate the footprint area was presented mainly with stochastic and analytical approaches, usually expensive. Thus this article aimed to develop a methodology based on geostatistics for inference of the footprint area for temperature and relative humidity. By using geostatistics it was possible to observe that the radius of footprint had a temporal variation (between times and days and spatial variation (between points, pointing out the great importance in assessing the footprint area. However, for a better analysis of this method we suggest to model the anisotropy in future studies, because the footprint area behaves like an ellipse with different radii at different directions. And for this, it is necessary to collect data with a regular distribution within a mesh.  

  6. Photocatalysis of gaseous trichloroethylene (TCE) over TiO{sub 2}: The effect of oxygen and relative humidity on the generation of dichloroacetyl chloride (DCAC) and phosgene

    Energy Technology Data Exchange (ETDEWEB)

    Ou, H.-H. [Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei 106, Taiwan (China); Lo, S.-L. [Research Center for Environmental Pollution Prevention and Control Technology, Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei 106, Taiwan (China)]. E-mail: sllo@ccms.ntu.edu.tw

    2007-07-19

    Batch photocatalytic degradation of 80 {+-} 2.5 ppmV trichloroethylene (TCE) was conducted to investigate the effect of the oxygen and relative humidity (RH) on the formation of the dichloroacetyl chloride (DCAC) and phosgene. Based on the simultaneous ordinary differential equations (ODEs), the reaction rate constants of TCE ((2.31 {+-} 0.28) {approx} (9.41 {+-} 0.63) x 10{sup -2} min{sup -1}) are generally larger than that of DCAC ((0.94 {+-} 1.25) {approx} (9.35 {+-} 1.71) x 10{sup -3} min{sup -1}) by approximate one order. The phenomenon indicates the degradation potential of TCE is superior to that of DCAC. DCAC appreciably delivers the same degradation behavior with TCE that means there exists an optimum RH and oxygen concentration for photocatalysis of TCE and DCAC. At the time the peak yield of DCAC appears, the conversion ratio based on the carbon atom from TCE to DCAC is within the range of 30-83% suggesting that the DCAC generation is significantly attributed to TCE degradation. Regarding the phosgene formation, the increasing oxygen amount leads to the inhibitory effect on the phosgene yield which fall within the range of 5-15%. The formation mechanism of phosgene was also inferred that the Cl atoms attacking the C-C bond of DCAC results to the generation of phosgene rather than directly from the TCE destruction.

  7. Influence of porosity and relative humidity on consolidation of dolostone with calcium hydroxide nanoparticles: Effectiveness assessment with non-destructive techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Arce, P., E-mail: plopezar@geo.ucm.es [Group of Applied Petrology to Heritage Conservation, Institute of Economic Geology (CSIC-UCM), Madrid 28040 (Spain); Gomez-Villalba, L.S. [Group of Applied Petrology to Heritage Conservation, Institute of Economic Geology (CSIC-UCM), Madrid 28040 (Spain); Pinho, L. [Center of Construction Studies, Engineering Faculty, Oporto University, Oporto 4200-465 (Portugal); Fernandez-Valle, M.E. [Research Assistance Center, Nuclear Magnetic Resonance (Pluridisciplinar Institute), Complutense University of Madrid (UCM), Madrid 28040 (Spain); Alvarez de Buergo, M.; Fort, R. [Group of Applied Petrology to Heritage Conservation, Institute of Economic Geology (CSIC-UCM), Madrid 28040 (Spain)

    2010-02-15

    Slaked lime (Ca(OH){sub 2}) nanoparticles were exposed at 33% and 75% relative humidity (RH) to consolidate dolostone samples used in historical buildings. Non-destructive techniques (NDT) were applied to determine the chemical, morphological, physical and hydric properties of the stone samples, before and after 20 days treatment. Morphological and mineralogical characterisation of the nanoparticles was performed. 75% RH favors the consolidation process studied under Environmental Scanning Electron Microscopy (ESEM-EDS), spectrophotometry, capillarity, water absorption under vacuum, ultrasound velocity, Nuclear Magnetic Resonance (imaging and relaxometry) and Optical Surface Roughness analyses. At 75% RH the nanoparticles fill the pores and inter-crystalline dolomite grain contacts but do not favor calcite re-crystallization as it occurs at 33% RH. The ESEM, XRD and TEM analyses under 75% RH reveal the fast transformation of portlandite (Ca(OH){sub 2}) into vaterite (CaCO{sub 3}), monohydrocalcite (CaCO{sub 3} . H{sub 2}O) and calcite (CaCO{sub 3}), and eventually the physical and hydric properties of the stones significantly improve. New insights are provided for the assessment of consolidation effectiveness of porous carbonate stones with calcium hydroxide nanoparticles under optimum RH conditions combining several NDT.

  8. Influence of porosity and relative humidity on consolidation of dolostone with calcium hydroxide nanoparticles: Effectiveness assessment with non-destructive techniques

    International Nuclear Information System (INIS)

    Lopez-Arce, P.; Gomez-Villalba, L.S.; Pinho, L.; Fernandez-Valle, M.E.; Alvarez de Buergo, M.; Fort, R.

    2010-01-01

    Slaked lime (Ca(OH) 2 ) nanoparticles were exposed at 33% and 75% relative humidity (RH) to consolidate dolostone samples used in historical buildings. Non-destructive techniques (NDT) were applied to determine the chemical, morphological, physical and hydric properties of the stone samples, before and after 20 days treatment. Morphological and mineralogical characterisation of the nanoparticles was performed. 75% RH favors the consolidation process studied under Environmental Scanning Electron Microscopy (ESEM-EDS), spectrophotometry, capillarity, water absorption under vacuum, ultrasound velocity, Nuclear Magnetic Resonance (imaging and relaxometry) and Optical Surface Roughness analyses. At 75% RH the nanoparticles fill the pores and inter-crystalline dolomite grain contacts but do not favor calcite re-crystallization as it occurs at 33% RH. The ESEM, XRD and TEM analyses under 75% RH reveal the fast transformation of portlandite (Ca(OH) 2 ) into vaterite (CaCO 3 ), monohydrocalcite (CaCO 3 . H 2 O) and calcite (CaCO 3 ), and eventually the physical and hydric properties of the stones significantly improve. New insights are provided for the assessment of consolidation effectiveness of porous carbonate stones with calcium hydroxide nanoparticles under optimum RH conditions combining several NDT.

  9. Effect of temperature and relative humidity on stability following simulated gastro-intestinal digestion of microcapsules of Bordo grape skin phenolic extract produced with different carrier agents.

    Science.gov (United States)

    Kuck, Luiza Siede; Wesolowski, Júlia Lerina; Noreña, Caciano Pelayo Zapata

    2017-09-01

    The stability of microparticles of Bordo grape skin aqueous extract, produced by spray-drying and freeze-drying using polydextrose (5%) and partially hydrolyzed guar gum (5%), was evaluated under accelerated conditions (75 and 90% relative humidity, at 35, 45, and 55°C for 35days) and simulated gastrointestinal digestion. The temperature had a significant effect on the reduction of phenolics content, with retentions varying from 82.5 to 93.5%. The retention of total monomer anthocyanins were in the range of 3.9-42.3%. The antioxidant activity had a final retention of 38.5-59.5%. In the simulated gastrointestinal digestion, a maximum release was observed for the phenolic compounds in the intestinal phase (90.6% for the spray-dried powder and 94.9% for the freeze-dried powder), as well as the antioxidant activity (69.4% for the spray-dried powder and 67.8% for the freeze-dried powder). However, a reduction of monomeric anthocyanins was observed in the intestinal phase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Effects of clamping force on the water transport and performance of a PEM (proton electrolyte membrane) fuel cell with relative humidity and current density

    International Nuclear Information System (INIS)

    Cha, Dowon; Ahn, Jae Hwan; Kim, Hyung Soon; Kim, Yongchan

    2015-01-01

    The clamping force should be applied to a proton electrolyte membrane (PEM) fuel cell due to its structural characteristics. The clamping force affects the ohmic and mass transport resistances in the PEM fuel cell. In this study, the effects of the clamping force on the water transport and performance characteristics of a PEM fuel cell are experimentally investigated with variations in the relative humidity and current density. The water transport characteristics were analyzed by calculating the net drag coefficient. The ohmic resistance decreased with the increase in the clamping force due to the reduced contact resistance and more even membrane hydration. However, the mass transport resistance increased with the increase in the clamping force due to the gas diffusion layer compression. The net drag coefficient decreased with the increase in the clamping force due to high water back-diffusion. Additionally, the relationship between the total resistance and the net drag coefficient was investigated. - Highlights: • Effects of clamping force on the performance of a PEM fuel cell are investigated. • Water transport characteristics are analyzed using net drag coefficient. • Ohmic resistance decreased with clamping force, but mass transport resistance increased. • Net drag coefficient decreased with the increase in clamping force. • Total resistance was significantly degraded for a net drag coefficient below 0.2.

  11. Controlled humidity gas circulators

    International Nuclear Information System (INIS)

    Gruner, S.M.

    1981-01-01

    A programmable circulator capable of regulating the humidity of a gas stream over a wide range of humidity is described. An optical dew-point hygrometer is used as a feedback element to control the addition or removal of water vapor. Typical regulation of the gas is to a dew-point temperature of +- 0.2 0 C and to an accuracy limited by the dew-point hygrometer

  12. Adolescents' and young adults' physical activity related to built environment

    Directory of Open Access Journals (Sweden)

    Armando Cocca

    2015-06-01

    Full Text Available Objectives. This study aims to analyse physical activity (PA levels of high school and university students; to estimate their perception of built environment with regard to physical PA; and to assess the relation between PA and built environment. Methods. A sociological cross-sectional study with non-experimental design was applied. The International Physical Activity Questionnaire and the Built Environment Characteristics Questionnaire were filled in by a sample of 1.862 students from high schools and the university in Granada, Spain. Results. High school students were significantly more active than university students, the latter reaching insufficient levels of PA. Nevertheless, they consider Granada as a good context for carrying out outdoor exercise. No relations were found between PA levels and built environment. Conclusion. The discrepant outcomes for PA levels and perceived built environment suggest the need of interventions focused on making youth aware of the possibilities that an environment provides to them for exercising. Consequently, environment could have an impact on their health at the same time as youth learn to respect it.

  13. Humidity control device in a reactor container

    International Nuclear Information System (INIS)

    Aizawa, Motohiro; Igarashi, Hiroo; Osumi, Katsumi; Kimura, Takashi.

    1986-01-01

    Purpose: To provide a device capable of maintaining the inside of a container under high humidity circumstantial conditions causing less atmospheric corrosions, in order to prevent injuries due to atmospheric corrosions to smaller diameter stainless steel pipeways in the reactor container. Constitution: Stress corrosion cracks (SCC) to the smaller diameter stainless steel pipeways are caused dependent on the relative humidity and it is effective as the countermeasure against SCC to maintain the relative humidity at a low level less than 30 % or high level greater than 60 %. Based on the above findings, a humidity control device is disposed so as to maintain the relative humidity for the atmosphere within a reactor core on a higher humidity region. The device is adapted such that recycling gas in the dry-well coolant circuit is passed through an orifice to atomize the water introduced from feedwater pipe and introduce into a reactor core or such that the recycling gases in the dry-well cooling circuit are bubbled into water to remove chlorine gas in the reactor container gas thereby increasing the humidity in the reactor container. (Kamimura, M.)

  14. 7 CFR 28.301 - Measurement: humidity; temperature.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Measurement: humidity; temperature. 28.301 Section 28... for Length of Staple § 28.301 Measurement: humidity; temperature. The length of staple of any cotton... its fibers under a relative humidity of the atmosphere of 65 percent and a temperature of 70° F. ...

  15. A Standard CMOS Humidity Sensor without Post-Processing

    OpenAIRE

    Nizhnik, Oleg; Higuchi, Kohei; Maenaka, Kazusuke

    2011-01-01

    A 2 ?W power dissipation, voltage-output, humidity sensor accurate to 5% relative humidity was developed using the LFoundry 0.15 ?m CMOS technology without post-processing. The sensor consists of a woven lateral array of electrodes implemented in CMOS top metal, a Intervia Photodielectric 8023?10 humidity-sensitive layer, and a CMOS capacitance to voltage converter.

  16. Coexistence of Dunes and Humid Conditions at Titan's Tropics

    Science.gov (United States)

    Radebaugh, Jani; Lorenz, R. D.; Lunine, J. I.; Kirk, R. L.; Ori, G. G.; Farr, T. G.; Malaska, M.; Le Gall, A.; Liu, Z. Y. C.; Encrenaz, P. J.; Paillou, P.; Hayes, A.; Lopes, R. M. C.; Turtle, E. P.; Wall, S. D.; Stofan, E. R.; Wood, C. A.; Cassini RADAR Team

    2012-10-01

    At Titan's equatorial latitudes there are tens of thousands of dunes, a landform typical of desert environments where sand does not become anchored by vegetation or fluids. Model climate simulations predict generally dry conditions at the equator and humid conditions near the poles of Titan, where lakes of methane/ethane are found. However, moderate relative methane humidity was observed at the Huygens landing site, recent rainfall was seen by Cassini ISS near the Belet Sand Sea, and a putative transient lake in Shangri-La was observed by Cassini VIMS, all of which indicate abundant fluids may be present, at least periodically, at Titan's equatorial latitudes. Terrestrial observations and studies demonstrate dunes can exist and migrate in conditions of high humidity. Active dunes are found in humid climates, indicating the movement of sand is not always prohibited by the presence of fluids. Sand mobility is related to precipitation, evaporation and wind speed and direction. If dune surfaces become wetted by rainfall or rising subsurface fluids, they can become immobilized. However, winds can act to dry the uppermost layers, freeing sands for saltation and enabling dune migration in wet conditions. Active dunes are found in tropical NE Brazil and NE Australia, where there are alternating dry and wet periods, a condition possible for Titan's tropics. Rising and falling water levels lead to the alteration of dune forms, mainly from being anchored by vegetation, but also from cementation by carbonates or clays. Studies of Titan's dunes, which could undergo anchoring of organic sediments by hydrocarbon fluids, could inform the relative strength of vegetation vs. cementation at humid dune regions on Earth. Furthermore, a comprehensive survey of dune morphologies near regions deemed low by SARTopo and stereo, where liquids may collect in wet conditions, could reveal if bodies of liquid have recently existed at Titan's tropics.

  17. Modelo de simulação da temperatura e umidade relativa do ar no interior de estufa plástica Simulation model of air temperature and relative humidity in to plastic greenhouses

    Directory of Open Access Journals (Sweden)

    Edilson Costa

    2004-04-01

    Full Text Available A simulação dos parâmetros climáticos de temperatura e umidade relativa do ar no interior de uma estufa plástica, por meio do balanço de energia, pode propiciar ao produtor uma ferramenta de auxílio na tomada de decisão. Nesse propósito, realizou-se uma simulação das condições no interior de estufa plástica, em função de parâmetros externos e internos a ela. A simulação revelou uma temperatura no interior da estufa plástica de 23,6 ºC, e os sensores revelaram um valor médio de 24,1 ºC para o período de cultivo da alface. Para a umidade relativa no interior da estufa plástica, o valor simulado foi de 61,6%, e o obtido com o auxílio de sensores foi de 66,0%. Os valores simulados apresentaram-se próximos dos valores obtidos pelos sensores, mostrando que o modelo pode ser usado para a estimativa da temperatura e umidade relativa do ar no interior da estufa plástica.Simulation of climatic parameters inside air temperature and relative humidity of plastic greenhouse, trough energy balance, allows to growers a good technical tool on the decision making to improve the performance of inside environments. A simulation of internal conditions based on external and internal parameters was evaluated. The results showed the inside mean temperature of 23.6 ºC in comparison with the experimental value of 24.1 ºC, for the cultivated period. The simulated relative humidity presented a value of 61.6% against 66.0% obtained by the sensors. The simulated values were closed to the values obtained by the sensors, which means that the model can be used to determine the internal conditions of plastic greenhouses.

  18. Characterization of spacecraft humidity condensate

    Science.gov (United States)

    Muckle, Susan; Schultz, John R.; Sauer, Richard L.

    1994-01-01

    When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

  19. Sporulation of Metarhizium anisopliae var. Acridum and Beauveria bassiana on Rhammatocerus schistocercoides under humid and dry conditions

    Directory of Open Access Journals (Sweden)

    Magalhães Bonifácio Peixoto

    2000-01-01

    Full Text Available The sporulation of the fungi Metarhizium anisopliae var. acridum and Beauveria bassiana in cadavers of the grasshopper Rhammatocerus schistocercoides was studied in dry and humid environments. Both fungi were equally virulent against R. schistocercoides. However, internally, M. anisopliae produced more conidia than B. bassiana at 53% and 75% relative humidity. Externally, there was no sporulation at 53% and 75% RH, and M. anisopliae produced more conidia than B. bassiana at 100% RH.

  20. Use of personalized ventilation for improving health, comfort, and performance at high room temperature and humidity

    DEFF Research Database (Denmark)

    Melikov, Arsen Krikor; Skwarczynski, Mariusz; Kaczmarczyk, J.

    2013-01-01

    in five 4-h experiments in a climate chamber. Under the conditions with PV, the subjects were able to control the rate and direction of the supplied personalized flow of clean air. Subjective responses were collected through questionnaires. During all exposures, the subjects were occupied with tasks used......The effect of personalized ventilation (PV) on people's health, comfort, and performance in a warm and humid environment (26 and 28°C at 70% relative humidity) was studied and compared with their responses in a comfortable environment (23°C and 40% relative humidity). Thirty subjects participated...... to assess their performance. Objective measures of tear film stability, concentration of stress biomarkers in saliva, and eye blinking rate were taken. Using PV significantly improved the perceived air quality (PAQ) and thermal sensation and decreased the intensity of Sick Building Syndrome (SBS) symptoms...

  1. Educational strategies used in increasing fluid intake and enhancing hydration status in field hockey players preparing for competition in a hot and humid environment: a case study.

    Science.gov (United States)

    Dabinett, J A; Reid, K; James, N

    2001-09-01

    The purpose of the present study was to develop a hydration strategy for use by female English field hockey players at the 1998 Commonwealth Games in Malaysia. An additional aim was to initiate the process of acclimation. Fifteen elite players, mean age (+/-SEM) 24.1 +/- 1.19 years, height 1.67 +/- 0.01 m, and body mass 62.8 +/- 1.76 kg, took part in a 5-day training camp immediately prior to departure for the Games. In order to develop the hydration strategy, training took place under similar environmental conditions to those to be experienced in Malaysia (i.e., 32 degrees C, 80% humidity). Acclimation training consisted of 30-50 min of either continuous, low intensity cycling or high intensity intermittent cycling, which more closely replicated the pattern of activity in field hockey. Body mass measures taken each morning, and pre and post training, together with urine color measures, were used to assess hydration status. Pre-loading with up to 1 L of a 3% carbohydrate-electrolyte solution or water immediately prior to acclimation training, as well as regular drinks throughout, ensured that players avoided significant dehydration, with percent body mass changes ranging from -0.34% to +4.24% post training. Furthermore, the protocol used was sufficient to initiate the process of acclimation as demonstrated by a significant reduction in exercising heart rate and core temperature at all time points by days 4 and 5. In conclusion, although labor intensive and time consuming, the camp was successful in developing a hydration strategy that players were able to utilize once at the Games.

  2. A molecular-scale study on the role of lactic acid in new particle formation: Influence of relative humidity and temperature

    Science.gov (United States)

    Li, Hao; Kupiainen-Määttä, Oona; Zhang, Haijie; Zhang, Xiuhui; Ge, Maofa

    2017-10-01

    It is well established that oxidation products of volatile organic compounds (VOCs) play a major role in atmospheric new-particle formation (NPF). However, the mechanism of their effect and the corresponding influence under various atmospheric conditions remain unclear. Meanwhile, considering the difficulty of experiment in determining the water content of the cluster and performing at low temperature, we combine Density Functional Theory (DFT) and Atmospheric Clusters Dynamic Code (ACDC) model to investigate a multicomponent system involving lactic acid (LA) and atmospheric nucleation precursors (sulfuric acid (SA), dimethylamine (DMA), water (W)) under a wide range of atmospheric conditions (relative humidity (RH) from 20% to 100%, temperature (T) from 220 K to 300 K). Conformational analysis shows that LA could enhance NPF in two direction due to its two highly oxidized function groups. Then, the results from ACDC simulation present a direct evidence of its enhancement effect on NPF when the concentration of LA is larger than 1010 molecules cm-3 . The corresponding enhancement strength presents a positive dependence on its concentrations and a negative dependence on RH and T, respectively. Besides, LA·nW (n = 0-1) reflect their enhancement effect on the cluster growth paths by acting as ;bridge;, which contributes to pure SA-DMA-W-based clusters by evaporating LA contained clusters. The corresponding contribution presents a positive dependence on the concentration of LA, RH and T, respectively. We hope our study could provide theoretical clues to better understand the characteristic of NPF in polluted area, where NPF commonly involves oxidized organics, sulfuric acid, amine and water.

  3. Heterogeneous reaction of SO2 with soot: The roles of relative humidity and surface composition of soot in surface sulfate formation

    Science.gov (United States)

    Zhao, Yan; Liu, Yongchun; Ma, Jinzhu; Ma, Qingxin; He, Hong

    2017-03-01

    The conversion of SO2 to sulfates on the surface of soot is still poorly understood. Soot samples with different fractions of unsaturated hydrocarbons and oxygen-containing groups were prepared by combusting n-hexane under well-controlled conditions. The heterogeneous reaction of SO2 with soot was investigated using in situ attenuated total internal reflection infrared (ATR-IR) spectroscopy, ion chromatography (IC) and a flow tube reactor at the ambient pressure and relative humidity (RH). Water promoted SO2 adsorption and sulfate formation at the RH range from 6% to 70%, while exceeded water condensed on soot was unfavorable for sulfate formation due to inhibition of SO2 adsorption when RH was higher than 80%. The surface composition of soot, which was governed by combustion conditions, also played an important role in the heterogeneous reaction of SO2 with soot. This effect was found to greatly depend on RH. At low RH of 6%, soot with the highest fuel/oxygen ratio of 0.162 exhibited a maximum uptake capacity for SO2 because it contained a large amount of aromatic Csbnd H groups, which acted as active sites for SO2 adsorption. At RH of 54%, soot produced with a fuel/oxygen ratio of 0.134 showed the highest reactivity toward SO2 because it contained appropriate amounts of aromatic Csbnd H groups and oxygen-containing groups, subsequently leading to the optimal surface concentrations of both SO2 and water. These results suggest that variation in the surface composition of soot from different sources and/or resulting from chemical aging in the atmosphere likely affects the conversion of SO2 to sulfates.

  4. To Evaluate the Effect of Solvents and Different Relative Humidity Conditions on Thermal and Rheological Properties of Microcrystalline Cellulose 101 Using METHOCEL™ E15LV as a Binder.

    Science.gov (United States)

    Jagia, Moksh; Trivedi, Maitri; Dave, Rutesh H

    2016-08-01

    The solvent used for preparing the binder solution in wet granulation can affect the granulation end point and also impact the thermal, rheological, and flow properties of the granules. The present study investigates the effect of solvents and percentage relative humidity (RH) on the granules of microcrystalline cellulose (MCC) with hydroxypropyl methyl cellulose (HPMC) as the binder. MCC was granulated using 2.5% w/w binder solution in water and ethanol/water mixture (80:20 v/v). Prepared granules were dried until constant percentage loss on drying, sieved, and further analyzed. Dried granules were exposed to different percentage RH for 48 h at room temperature. Powder rheometer was used for the rheological and flow characterization, while thermal effusivity and differential scanning calorimeter were used for thermal analysis. The thermal effusivity values for the wet granules showed a sharp increase beginning 50% w/w binder solution in both cases, which reflected the over-wetting of granules. Ethanol/water solvent batches showed greater resistance to flow as compared to the water solvent batches in the wet granule stage, while the reverse was true for the dried granule stage, as evident from the basic flowability energy values. Although the solvents used affected the equilibration kinetics of moisture content, the RH-exposed granules remained unaffected in their flow properties in both cases. This study indicates that the solvents play a vital role on the rheology and flow properties of MCC granules, while the different RH conditions have little or no effect on them for the above combination of solvent and binder.

  5. Short communication: Little change takes place in Camembert-type cheese water activities throughout ripening in terms of relative humidity and salt.

    Science.gov (United States)

    Leclercq-Perlat, M-N; Hélias, A; Corrieu, G

    2013-01-01

    Water activity (a(w)) affects the growth and activity of ripening microorganisms. Moreover, it is generally accepted that a(w) depends on relative humidity (RH) and salt content; these 3 variables were usually measured on a given day in a cheese without the microorganism layer and without accounting for a distinction between the rind, the underrind, and the core. However, a(w) dynamics have never been thoroughly studied throughout cheese ripening. Experimental Camembert cheeses were ripened under controlled and aseptic conditions (temperature, gaseous atmosphere, and RH) for 14 d. In this study, only RH was varied. Samples were taken from the cheese (microorganism layer)-air interface, the rind, and the core. The aw of the cheese-air interface did not change over ripening when RH varied between 91 and 92% or between 97 and 98%. However, on d 5, we observed a small but significant increase in a(w), which coincided with the beginning of growth of Penicillium camemberti mycelia. After d 3, no significant differences were found between the a(w) of the cheese-air interface, the rind, and the core. From d 0 to 3, cheese rind a(w) increased from 0.94 to 0.97, which was probably due to the diffusion of salt from the rind to the core: NaCl content in the rind decreased from 3.7 to 1.6% and NaCl content in the core increased from 0.0 to 1.6%. Nevertheless, aw did not significantly vary in the core, raising questions about the real effect of salt on a(w).

  6. On the comparisons of tropical relative humidity in the lower and middle troposphere among COSMIC radio occultations and MERRA and ECMWF data sets

    Science.gov (United States)

    Vergados, P.; Mannucci, A. J.; Ao, C. O.; Jiang, J. H.; Su, H.

    2015-04-01

    The spatial variability of the tropical tropospheric relative humidity (RH) throughout the vertical extent of the troposphere is examined using Global Positioning System Radio Occultation (GPSRO) observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission. These high vertical resolution observations capture the detailed structure and moisture budget of the Hadley Cell circulation. We compare the COSMIC observations with the European Center for Medium-range Weather Forecast (ECMWF) Reanalysis Interim (ERA-Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) climatologies. Qualitatively, the spatial pattern of RH in all data sets matches up remarkably well, capturing distinct features of the general circulation. However, RH discrepancies exist between ERA-Interim and COSMIC data sets that are noticeable across the tropical boundary layer. Specifically, ERA-Interim shows a drier Intertropical Convergence Zone (ITCZ) by 15-20% compared to both COSMIC and MERRA data sets, but this difference decreases with altitude. Unlike ECMWF, MERRA shows an excellent agreement with the COSMIC observations except above 400 hPa, where GPSRO observations capture drier air by 5-10%. RH climatologies were also used to evaluate intraseasonal variability. The results indicate that the tropical middle troposphere at ±5-25° is most sensitive to seasonal variations. COSMIC and MERRA data sets capture the same magnitude of the seasonal variability, but ERA-Interim shows a weaker seasonal fluctuation up to 10% in the middle troposphere inside the dry air subsidence regions of the Hadley Cell. Over the ITCZ, RH varies by maximum 9% between winter and summer.

  7. On the comparisons of tropical relative humidity in the lower and middle troposphere among COSMIC radio occultations, MERRA and ECMWF data sets

    Science.gov (United States)

    Vergados, P.; Mannucci, A. J.; Ao, C. O.; Jiang, J. H.; Su, H.

    2015-01-01

    The spatial variability of the tropical tropospheric relative humidity (RH) throughout the vertical extent of the troposphere is examined using Global Positioning System Radio Occultation (GPSRO) observations from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission. These high vertical resolution observations capture the detailed structure and moisture budget of the Hadley Cell circulation. We compare the COSMIC observations with the European Center for Medium-range Weather Forecast (ECMWF) Re-Analysis Interim (ERA-Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) climatologies. Qualitatively, the spatial pattern of RH in all data sets matches up remarkably well, capturing distinct features of the general circulation. However, RH discrepancies exist between ERA-Interim and COSMIC data sets, which are noticeable across the tropical boundary layer. Specifically, ERA-Interim shows a drier Inter Tropical Convergence Zone (ITCZ) by 15-20% compared both to COSMIC and MERRA data sets, but this difference decreases with altitude. Unlike ECMWF, MERRA shows an excellent agreement with the COSMIC observations except above 400 hPa, where GPSRO observations capture drier air by 5-10%. RH climatologies were also used to evaluate intraseasonal variability. The results indicate that the tropical middle troposphere at ±5-25° is most sensitive to seasonal variations. COSMIC and MERRA data sets capture the same magnitude of the seasonal variability, but ERA-Interim shows a weaker seasonal fluctuation up to 10% in the middle troposphere inside the dry air subsidence regions of the Hadley Cell. Over the ITCZ, RH varies by maximum 9% between winter and summer.

  8. Assessment of the environment-related problems and prospects of ...

    African Journals Online (AJOL)

    The study attempted to assess the environment-related problems and prospects of vegetable production in peri – urban areas of Lagos state, Nigeria. A total of one hundred and twenty (120) farmers were interviewed. Data collected were analyzed using frequency, percentages and Pearson Product Moment Correlation ...

  9. The rehabilitation team: staff perceptions of the hospital environment, the interdisciplinary team environment, and interprofessional relations.

    Science.gov (United States)

    Strasser, D C; Falconer, J A; Martino-Saltzmann, D

    1994-02-01

    Although inpatient rehabilitation is an interdisciplinary activity organized around a treatment team, there is a limited understanding of the workings of the interdisciplinary process. To elucidate staff perceptions of key aspects of the rehabilitation treatment process, we surveyed staff (n = 113) from selected inpatient teams. The staff completed social psychological instruments that measure perceptions of the hospital environment (The Ward Atmosphere Scale [WAS]), the team's environment (the Group Environment Scale [GES]), and interprofessional relations (Interprofessional Perception Scale [IPS]). Rehabilitation staff generally endorse the team approach, but express concerns over professional boundaries. Interprofessional difficulties seemed to be independent of team membership or professional training. Compared with published data from other settings, rehabilitation teams resembled task-oriented groups, but showed significant differences across teams in their perceptions of the team and hospital environments. The task-oriented character of rehabilitation teams, team-specific characteristics, and discord in interprofessional relationships may need to be considered in studies of rehabilitation teams effectiveness.

  10. Determining the critical relative humidity at which the glassy to rubbery transition occurs in polydextrose using an automatic water vapor sorption instrument.

    Science.gov (United States)

    Yuan, Xiaoda; Carter, Brady P; Schmidt, Shelly J

    2011-01-01

    Similar to an increase in temperature at constant moisture content, water vapor sorption by an amorphous glassy material at constant temperature causes the material to transition into the rubbery state. However, comparatively little research has investigated the measurement of the critical relative humidity (RHc) at which the glass transition occurs at constant temperature. Thus, the central objective of this study was to investigate the relationship between the glass transition temperature (Tg), determined using thermal methods, and the RHc obtained using an automatic water vapor sorption instrument. Dynamic dewpoint isotherms were obtained for amorphous polydextrose from 15 to 40 °C. RHc was determined using an optimized 2nd-derivative method; however, 2 simpler RHc determination methods were also tested as a secondary objective. No statistical difference was found between the 3 RHc methods. Differential scanning calorimetry (DSC) Tg values were determined using polydextrose equilibrated from 11.3% to 57.6% RH. Both standard DSC and modulated DSC (MDSC) methods were employed, since some of the polydextrose thermograms exhibited a physical aging peak. Thus, a tertiary objective was to compare Tg values obtained using 3 different methods (DSC first scan, DSC rescan, and MDSC), to determine which method(s) yielded the most accurate Tg values. In general, onset and midpoint DSC first scan and MDSC Tg values were similar, whereas onset and midpoint DSC rescan values were different. State diagrams of RHc and experimental temperature and Tg and %RH were compared. These state diagrams, though obtained via very different methods, showed relatively good agreement, confirming our hypothesis that water vapor sorption isotherms can be used to directly detect the glassy to rubbery transition. Practical Application: The food polymer science (FPS) approach, pioneered by Slade and Levine, is being successfully applied in the food industry for understanding, improving, and

  11. Hands-on Humidity.

    Science.gov (United States)

    Pankiewicz, Philip R.

    1992-01-01

    Presents five hands-on activities that allow students to detect, measure, reduce, and eliminate moisture. Students make a humidity detector and a hygrometer, examine the effects of moisture on different substances, calculate the percent of water in a given food, and examine the absorption potential of different desiccants. (MDH)

  12. Sensitivity of honeybee hygroreceptors to slow humidity changes and temporal humidity variation detected in high resolution by mobile measurements.

    Science.gov (United States)

    Tichy, Harald; Kallina, Wolfgang

    2014-01-01

    The moist cell and the dry cell on the antenna of the male honeybee were exposed to humidities slowly rising and falling at rates between -1.5%/s and +1.5%/s and at varying amplitudes in the 10 to 90% humidity range. The two cells respond to these slow humidity oscillations with oscillations in impulse frequency which depend not only on instantaneous humidity but also on the rate with which humidity changes. The impulse frequency of each cell was plotted as a function of these two parameters and regression planes were fitted to the data points of single oscillation periods. The regression slopes, which estimate sensitivity, rose with the amplitude of humidity oscillations. During large-amplitude oscillations, moist and dry cell sensitivity for instantaneous humidity and its rate of change was high. During small-amplitude oscillations, their sensitivity for both parameters was low, less exactly reflecting humidity fluctuations. Nothing is known about the spatial and temporal humidity variations a honeybee may encounter when flying through natural environments. Microclimatic parameters (absolute humidity, temperature, wind speed) were measured from an automobile traveling through different landscapes of Lower Austria. Landscape type affected extremes and mean values of humidity. Differences between peaks and troughs of humidity fluctuations were generally smaller in open grassy fields or deciduous forests than in edge habitats or forest openings. Overall, fluctuation amplitudes were small. In this part of the stimulus range, hygroreceptor sensitivity is not optimal for encoding instantaneous humidity and the rate of humidity change. It seems that honeybee's hygroreceptors are specialized for detecting large-amplitude fluctuations that are relevant for a specific behavior, namely, maintaining a sufficiently stable state of water balance. The results suggest that optimal sensitivity of both hygroreceptors is shaped not only by humidity oscillation amplitudes but also

  13. Reversible adhesion switching of porous fibrillar adhesive pads by humidity.

    Science.gov (United States)

    Xue, Longjian; Kovalev, Alexander; Dening, Kirstin; Eichler-Volf, Anna; Eickmeier, Henning; Haase, Markus; Enke, Dirk; Steinhart, Martin; Gorb, Stanislav N

    2013-01-01

    We report reversible adhesion switching on porous fibrillar polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP) adhesive pads by humidity changes. Adhesion at a relative humidity of 90% was more than nine times higher than at a relative humidity of 2%. On nonporous fibrillar adhesive pads of the same material, adhesion increased only by a factor of ~3.3. The switching performance remained unchanged in at least 10 successive high/low humidity cycles. Main origin of enhanced adhesion at high humidity is the humidity-induced decrease in the elastic modulus of the polar component P2VP rather than capillary force. The presence of spongelike continuous internal pore systems with walls consisting of P2VP significantly leveraged this effect. Fibrillar adhesive pads on which adhesion is switchable by humidity changes may be used for preconcentration of airborne particulates, pollutants, and germs combined with triggered surface cleaning.

  14. Corrigendum to “Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines” [Agric. Forest Meteorol. 165 (2012) 53–63

    DEFF Research Database (Denmark)

    Fratini, Gerardo; Ibrom, Andreas; Arriga, Nicola

    2012-01-01

    It has been formerly recognised that increasing relative humidity in the sampling line of closed-path eddy-covariance systems leads to increasing attenuation of water vapour turbulent fluctuations, resulting in strong latent heat flux losses. This occurrence has been analyzed for very long (50 m...... from eddy-covariance systems featuring short (4 m) and very short (1 m) sampling lines running at the same clover field and show that relative humidity effects persist also for these setups, and should not be neglected. Starting from the work of Ibrom and co-workers, we propose a mixed method...... and correction method proposed here is deemed applicable to closed-path systems featuring a broad range of sampling lines, and indeed applicable also to passive gases as a special case. The methods described in this paper are incorporated, as processing options, in the free and open-source eddy...

  15. Humidity Response of Polyaniline Based Sensor

    Directory of Open Access Journals (Sweden)

    Mamta PANDEY

    2010-02-01

    Full Text Available Abstract: This paper presents hitherto unreported humidity sensing capacity of emeraldine salt form of polyaniline. Humidity plays a major role in different processes in industries ranging from food to electronic goods besides human comfort and therefore its monitoring is an essential requirement during various processes. Polyaniline has a wide use for making sensors as it can be easily synthesized and has long stability. Polyaniline is synthesized here by chemical route and is found to sense humidity as it shows variation in electrical resistance with variation in relative humidity. Results are presented here for a range of 15 to 90 RH%. The resistance falls from 5.8 to 0.72 Giga ohms as RH varies from 15 to 65 % and then falls to 13.9 Mega ohms as RH approaches 90 %. The response and recovery times are also measured.

  16. Assessing the influence of NOx concentrations and relative humidity on secondary organic aerosol yields from α-pinene photo-oxidation through smog chamber experiments and modelling calculations

    Science.gov (United States)

    Stirnweis, Lisa; Marcolli, Claudia; Dommen, Josef; Barmet, Peter; Frege, Carla; Platt, Stephen M.; Bruns, Emily A.; Krapf, Manuel; Slowik, Jay G.; Wolf, Robert; Prévôt, Andre S. H.; Baltensperger, Urs; El-Haddad, Imad

    2017-04-01

    Secondary organic aerosol (SOA) yields from the photo-oxidation of α-pinene were investigated in smog chamber (SC) experiments at low (23-29 %) and high (60-69 %) relative humidity (RH), various NOx / VOC ratios (0.04-3.8) and with different aerosol seed chemical compositions (acidic to neutralized sulfate-containing or hydrophobic organic). A combination of a scanning mobility particle sizer and an Aerodyne high-resolution time-of-flight aerosol mass spectrometer was used to determine SOA mass concentration and chemical composition. We used a Monte Carlo approach to parameterize smog chamber SOA yields as a function of the condensed phase absorptive mass, which includes the sum of OA and the corresponding bound liquid water content. High RH increased SOA yields by up to 6 times (1.5-6.4) compared to low RH. The yields at low NOx / VOC ratios were in general higher compared to yields at high NOx / VOC ratios. This NOx dependence follows the same trend as seen in previous studies for α-pinene SOA. A novel approach of data evaluation using volatility distributions derived from experimental data served as the basis for thermodynamic phase partitioning calculations of model mixtures in this study. These calculations predict liquid-liquid phase separation into organic-rich and electrolyte phases. At low NOx conditions, equilibrium partitioning between the gas and liquid phases can explain most of the increase in SOA yields observed at high RH, when in addition to the α-pinene photo-oxidation products described in the literature, fragmentation products are added to the model mixtures. This increase is driven by both the increase in the absorptive mass and the solution non-ideality described by the compounds' activity coefficients. In contrast, at high NOx, equilibrium partitioning alone could not explain the strong increase in the yields with RH. This suggests that other processes, e.g. reactive uptake of semi-volatile species into the liquid phase, may occur and be

  17. Concentrations of Staphylococcus species in indoor air as associated with other bacteria, season, relative humidity, air change rate, and S. aureus-positive occupants.

    Science.gov (United States)

    Madsen, Anne Mette; Moslehi-Jenabian, Saloomeh; Islam, Md Zohorul; Frankel, Mika; Spilak, Michal; Frederiksen, Margit W

    2018-01-01

    The aim of this study was to obtain knowledge about concentrations of Staphylococcus aureus, MRSA (methicillin-resistant S. aureus), and other Staphylococcus species in indoor air in Greater Copenhagen and about factors affecting the concentrations. The effects of season, temperature, relative humidity, air change rate (ACR), other bacterial genera, area per occupant, and presence of S. aureus-positive occupants were studied. In samples from 67 living rooms, S. hominis, S. warneri, S. epidermidis, and S. capitis were found in 13-25%; S. saprophyticus, S. cohnii, and S. pasteuri in 5-10%; and S. lugdunensis, S. haemolyticus, S. caprae, S. equorum, S. kloosii, S. pettenkoferi, S. simulans, and S. xylosus in less than 3%. Staphylococcus aureus were found in two of 67 living rooms: spa type t034 (an MRSA) was recovered from a farmhouse, while spa type t509 was found in an urban home. Two species, S. equorum and S. kloosii, were found only in the farmhouse. Staphylococcus was significantly associated with season with lowest concentration and richness in winter. Genera composition was associated with ACR with smaller fractions of Staphylococcus at higher ACR, while richness was significantly and negatively associated with area per occupant. Concentration of Staphylococcus correlated positively with the total concentration of bacteria, but negatively with the total concentration of other bacteria. The concentration of Staphylococcus was not significantly associated with concentrations of the other abundant genera Bacillus, Kocuria, and Micrococcus. In offices with S. aureus-positive occupants, airborne S. aureus was not found. In conclusion, Staphylococcus species constitute a considerable proportion of the airborne bacteria in the studied homes and offices. However, both S. aureus and MRSA had very low prevalence during all seasons. Thus, transmission of S. aureus and MRSA through the air in living rooms in Copenhagen is expected to be limited. The negative associations

  18. Reconstruction of late Quaternary relative humidity changes on the southern slopes of Mt. Kilimanjaro, East Africa, using a coupled δ2H-δ18O biomarker paleohygrometer

    Science.gov (United States)

    Hepp, Johannes; Zech, Roland; Rozanski, Kazimierz; Tuthorn, Mario; Glaser, Bruno; Greule, Markus; Keppler, Frank; Huang, Yongsong; Zech, Wolfgang; Zech, Michael

    2016-04-01

    Our understanding of African paleoclimate/-hydrological history is decisively based on lake level and lake sediment studies. It furthermore improved remarkably during the last decade thanks to emerging stable isotope techniques such as compound-specific deuterium analysis of sedimentary leaf wax biomarkers (δ2Hleaf wax). Here we present results from a multi-proxy biomarker study carried out on a ~100 ka paleosol sequence developed in the Maundi crater at ~2780 m a.s.l. on the southeastern slopes of Mt. Kilimanjaro in equatorial East Africa. The Maundi stable isotope records established for hemicellulose-derived sugars, lignin- and pectin-derived methoxyl groups and leaf wax-derived fatty acid and n-alkane biomarkers (δ18Osugars, δ2Hmethoxyl groups, δ2Hfatty acids and δ2Hn-alkanes) reveal differences but also similar patterns. Maxima characterize the period from 70 to 60 ka, the last glacial maximum (LGM) and the Younger Dryas (YD), whereas minima occur during the Holocene. The application of a 'coupled δ2Hn-alkane-δ18Osugar paleohygrometer' allows the reconstruction of the Late Quaternary relative humidity (RH) history of the Maundi study site. Accordingly, the reconstructed RH changes are well in agreement with the Maundi pollen results. Apart from the overall regional moisture availability, the intensification versus weakening of the trade wind inversion, which affects the diurnal montane atmospheric circulation on the slopes of Mt. Kilimanjaro, is suggested as local second important factor controlling the RH history at Maundi. Furthermore, the Maundi results of the coupled δ2Hn-alkane-δ18Osugar approach caution against interpreting δ2Hleaf wax (as well as δ18Osugar) records straight forwards in terms of reflecting δ2Hprec, because variably and primarily RH-dependent isotopic evapotranspirative enrichment of leaf water can mask δ2Hprec changes. Concerning the biomarker-based reconstructed Maundi δ2H/δ18Oprec record, the comparison with the

  19. Numerical study of the effect of relative humidity and stoichiometric flow ratio on PEM (proton exchange membrane) fuel cell performance with various channel lengths: An anode partial flooding modelling

    International Nuclear Information System (INIS)

    Xing, Lei; Cai, Qiong; Xu, Chenxi; Liu, Chunbo; Scott, Keith; Yan, Yongsheng

    2016-01-01

    A two dimensional, along the channel, non-isothermal, two-phase flow, anode partial flooding model was developed to investigate the effects of relative humidity, stoichiometric flow ratio and channel length, as well as their interactive influence, on the performance of a PEM (proton exchange membrane) fuel cell. Liquid water formation and transport at the anode due to the condensation of supersaturated anode gas initiated by hydrogen consumption was considered. The model considered the heat source/sink in terms of electrochemical reaction, Joule heating and latent heat due to water phase-transfer. The non-uniform temperature distributions inside the MEA (membrane electrode assembly) and channels at various stoichiometric flow ratios were demonstrated. The Peclet number was used to evaluate the contributions of advection and diffusion on liquid water and heat transport. Results indicated that higher anode relative humidity is required to the improved cell performance. As the decrease in the anode relative humidity and increase in channel length, the optimal cathode relative humidity was increased. The initial increase in stoichiometric flow ratio improved the limiting current densities. However, the further increases led to limited contributions. The Peclet number indicated that the liquid water transport through the electrode was mainly determined by the capillary diffusion mechanism. - Highlights: • Interactive effects of RH, stoichiometric flow ratio, channel length are studied. • Fully humidified anode is required to maintain the good cell performance. • Optimal RH_c is 30–40% for channel length of 1–10 cm at high current density. • Effect of stoichiometric flow ratio is more significant for longer channels. • Both liquid water and heat transport are diffusion dominated rather than advection.

  20. Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

    OpenAIRE

    Majewski Jacek

    2017-01-01

    Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based ...

  1. Bilayer-structured nanocomposite of Ag and crosslinked polyelectrolyte for the detection of humidity

    International Nuclear Information System (INIS)

    Li, Yang; Wu, Taotao; Yang, Mujie

    2015-01-01

    Nanocomposites of quaternized and crosslinked poly(4-vinylpyridine) (QC-P4VP) and silver nanoparticles were prepared by a two-step procedure, and characterized by Fourier-transform infrared spectroscopy, Ultraviolet–visible spectroscopy and scanning electron microscopy. Bilayer-structured humidity sensors based on the nanocomposites were fabricated, and the effects of the concentration of silver salt precursor and poly(4-vinylpyridine), the method for the reduction of silver salt, the deposition order of the sensitive layers and environmental temperature on the humidity sensing characteristics of the composite sensor have been examined at room temperature. The composite sensor exhibited low impedance under dry atmosphere due to the introduction of Ag nanoparticles, and could detect very low relative humidity (RH) (down to 1% RH) with good sensitivity (impedance change of 2000% from 1% to 30% RH). In addition, the composite sensor demonstrated very wide measuring range (1–98% RH), and revealed faster response and smaller hysteresis than the sensor based on QC-P4VP alone. The complex impedance spectra of the composite sensor in the environments with different RH levels were investigated to explore its humidity sensing mechanism. - Highlights: • Bilayer-structured nanocomposite of Ag and polyelectrolyte are facilely prepared. • Nanocomposite could measure humidity as low as 1% RH and show small hysteresis. • Nanocomposite is capable of detecting full-range humidity with high sensitivity

  2. Tightness Entropic Uncertainty Relation in Quantum Markovian-Davies Environment

    Science.gov (United States)

    Zhang, Jun; Liu, Liang; Han, Yan

    2018-05-01

    In this paper, we investigate the tightness of entropic uncertainty relation in the absence (presence) of the quantum memory which the memory particle being weakly coupled to a decohering Davies-type Markovian environment. The results show that the tightness of the quantum uncertainty relation can be controlled by the energy relaxation time F, the dephasing time G and the rescaled temperature p, the perfect tightness can be arrived by dephasing and energy relaxation satisfying F = 2G and p = 1/2. In addition, the tightness of the memory-assisted entropic uncertainty relation and the entropic uncertainty relation can be influenced mainly by the purity. While in memory-assisted model, the purity and quantum correlation can also influence the tightness actively while the quantum entanglement can influence the tightness slightly.

  3. Methods of humidity determination Part II: Determination of material humidity

    OpenAIRE

    Rübner, Katrin; Balköse, Devrim; Robens, E.

    2008-01-01

    Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.

  4. Strategies for humidity control

    Energy Technology Data Exchange (ETDEWEB)

    Baumgarth, S

    1987-01-01

    Humidity and temperature control in air-conditioning systems mostly involves coupled closed-loop control circuits. The author discusses their uncoupling and resulting consequences as well as energy-optimized control of recirculation air flaps or enthalpy recovering systems (h-x control) in detail. Special reference is made of the application of the DDC technology and its scope, limits and preconditions. In conclusions, the author presents pertinent measurement results. (orig.).

  5. Methods and systems relating to an augmented virtuality environment

    Science.gov (United States)

    Nielsen, Curtis W; Anderson, Matthew O; McKay, Mark D; Wadsworth, Derek C; Boyce, Jodie R; Hruska, Ryan C; Koudelka, John A; Whetten, Jonathan; Bruemmer, David J

    2014-05-20

    Systems and methods relating to an augmented virtuality system are disclosed. A method of operating an augmented virtuality system may comprise displaying imagery of a real-world environment in an operating picture. The method may further include displaying a plurality of virtual icons in the operating picture representing at least some assets of a plurality of assets positioned in the real-world environment. Additionally, the method may include displaying at least one virtual item in the operating picture representing data sensed by one or more of the assets of the plurality of assets and remotely controlling at least one asset of the plurality of assets by interacting with a virtual icon associated with the at least one asset.

  6. International Relations and the environment: practical examples of environmental multilateralism

    Directory of Open Access Journals (Sweden)

    Filipa Tiago Gomes

    2012-01-01

    Full Text Available The “environmental crisis” we experience today and the international community’s struggle to develop environmental standards to reach the epic “sustainable development” are widely known topics. What is needed, then, is an urgent and determined practice, which is only possible if international governance is structured, coherent and effective. The optimization of Environmental Multilateralism (the joining of what are considered the “driving forces” of Environmental International Relations: Law, Politics and international Diplomacy contributes greatly to this end. To understand its basic concepts and systems, as for example, its actors, negotiation and implementation of Multilateral Environmental Agreements (MEAs and the carrying out of their Regimes, as well as their development in the United Nations, these are all crucial elements for its improvement and optimization. The United Nations Conference on Environment and Development (Rio de Janeiro, 1992 and “its” Conventions are important examples in the history of Environmental Multilateralism, still very up-to-date not only due to the 20th anniversary of the “Rio Conference” but also due to the continuity and importance that the “Rio Conventions” and their Conferences of Parties (COP still have. This papers aims to analyze this area of studies transversal to International Relations and to the Environment, namely by studying the relation between the theory of Environmental Multilateralism and its practice.

  7. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    Science.gov (United States)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.

  8. Midday depression of CO/sub 2/ assimilation in leaves of Arbutus unedo L. : diurnal changes in photosynthetic capacity related to changes in temperature and humidity

    Energy Technology Data Exchange (ETDEWEB)

    Raschke, K.; Resemann, A.

    1986-01-01

    Parts of the attached leaves of the sclerophyllous shrub Arbutus unedo were subjected to simulated mediterranean days. Gas exchange was recorded in order to recognize the causes of the midday depression in CO/sub 2/ assimilation. Depressions could be induced in part of a leaf: they were local responses. The CO/sub 2/-saturation curves of photosynthesis, determined during the morning and afternoon maxima of CO/sub 2/ assimilation and during the minimum at midday, established that depressions in CO/sub 2/ assimilation were in one-half of the investigated cases totally caused by reversible reductions in the photosynthetic capacity of the leaves, and in other half almost totally caused by such reductions. There was no correlation between the water loss with the degree of reduction of the photosynthetic capacity. However, depressions occurred if an apparent threshold in the water-vapor pressure difference between leaf and air was exceeded. In another set of experiments, leaves were subjected to variations in temperature and humidity independent of the time of the day, under otherwise constant conditions. Photosynthetic capacity and stomatal conductance proved to be almost insensitive to changes in temperature (in a range extending from 20 to 37/sup 0/C) as long as the water vapor-pressure difference was held constant. If it was not, the rate of photosynthesis began to decline with increasing temperature after a threshold water-vapor pressure difference was exceeded. The position of the resulting apparent temperature optimum of photosynthesis depended on the humidity of the air. The authors suggest that the ability of A. unedo to respond to a dry atmosphere with a reversible reduction of its photosynthetic capacity (by a still unknown mechanism) is the result of a co-evolution with the development of a strong stomatal sensitivity to changes in humidity. 26 references, 14 figures.

  9. CONSUMERS’ BEHAVIOURS RELATED TO PACKAGING AND THEIR ATTITUDES TOWARDS ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Marzena Jeżewska-Zychowicz

    2015-09-01

    Full Text Available The aim of the research was to establish the relationship between the attitude of consumers towards the environment and their behaviours when choosing food products taking into consideration their packaging. This relationship was established according to gender, age and the educational level of the consumers. Questionnaire study was carried out in 2010 within 548 adults from Warsaw. Participants were asked questions on attitudes towards environment and behaviours related to reduction of packaging waste. Frequency, factor and cluster analysis were used. Signifi cantly more women than men agreed that buying pro ducts in larger packages and beverages in glass bottles can reduce the amount of garbage. Over twice more people with positive attitude claimed not buying food in disposable plastic or paper packaging. Negative attitude fostered doing nothing to minimize waste packaging. Attitudes towards the environment have had signifi - cant impact on the choice of food packaging. More positive attitudes favoured the reduction of the amount of packaging waste. Thus, environmental campaigns focused on attitudes and environmentally relevant use of food packing are required.

  10. Temperature, humidity and time. Combined effects on radiochromic film dosimeters

    DEFF Research Database (Denmark)

    Abdel-Fattah, A.A.; Miller, A.

    1996-01-01

    The effects of both relative humidity and temperature during irradiation on the dose response of FWT-60-00 and Riso B3 radiochromic film dosimeters have been investigated in the relative humidity (RH) range 11-94% and temperature range 20-60 degrees C for irradiation by Co-60 photons and 10-Me......V electrons. The results show that humidity and temperature cannot be treated as independent variables, rather there appears to be interdependence between absorbed dose, temperature, and humidity. Dose rate does not seem to play a significant role. The dependence of temperature during irradiation is +0.......25 +/- 0.1% per degrees C for the FWT-60-00 dosimeters and +0.5 +/- 0.1% per degrees C For Riso B3 dosimeters at temperatures between 20 and 50 degrees C and at relative humidities between 20 and 53%. At extreme conditions both with respect to temperature and to humidity, the dosimeters show much stronger...

  11. Corrosion of steel in concrete in cooling water walls. Report part 2 - Effects of the relative humidity on chlorine-initiated corrosion of the reinforcing steel; Korrosion paa staal i betong i kylvattenvaegar. Delrapport 2 - Relativa fuktighetens inverkan paa kloridinitierad armeringskorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Bertil; Ahlstroem, Johan; Sederholm, Bror; Nilsson, Lars-Olof; Lindmark, Sture

    2010-04-15

    Steel in concrete is protected against corrosion by the high pH value of the concrete. The passivity can however be broken if chloride ions penetrate into the concrete. It is presumed that a certain amount of chloride is needed to activate the steel. This value is called the threshold level. Even though many attempts have been performed no reliable value has been found. One of the reasons for this is probably that the threshold value is influenced by the humidity of the concrete. At very high humidity the transport of oxygen to the steel surface is slow and at low humidity the electrical resistance increases. The aim of this investigation has been to determine at what humidity the corrosion rate reaches its highest value. With this as a background new tests can be performed to predict the chloride threshold value. The results indicate that it most probably do exist a threshold value for each concrete quality. At chloride contents above the threshold value the steel looses its passivity. If severe corrosion takes place or not is however strongly dependent on the humidity of the concrete. In a close interval around 95 % relative humidity the steel is attacked by pitting corrosion when the threshold value is exceeded. At lower and higher humidity the passivity is incomplete and the corrosion rate in most cases marginal. Future investigations concerning chloride threshold values is recommended to be performed at a relative humidity of 95 % and by using reference samples according to proposed procedure.

  12. An electro-active paper actuator made with cellulose–polypyrrole–ionic liquid nanocomposite: influence of ionic liquid concentration, type of anion and humidity

    International Nuclear Information System (INIS)

    Mahadeva, Suresha K; Kim, Jaehwan

    2010-01-01

    This paper reports a cellulose–polypyrrole–ionic liquid (CPIL) nanocomposite that can produce large actuating displacement in a low humidity environment. The fabrication process and actuator performance of the CPIL nanocomposite actuator are illustrated. Experimental results revealed that the size of anion, concentration of ionic liquid and ambient humidity level have a significant influence on the actuator performance of the CPIL nanocomposite. The bending displacement of the CPIL nanocomposite actuator was enhanced with increasing anion size, ionic liquid concentration and humidity level. CPIL nanocomposite made with 4% BMIBF 4 ionic liquid exhibited a very large bending displacement with excellent durability under ambient conditions (30% relative humidity and 25 °C). This is probably the first report that cellulose based electro-active paper actuator can exhibit such a large bending displacement under ambient conditions. Experimental results revealed that the proposed CPIL nanocomposite actuator under study can be operated up to 70% humidity level

  13. Propagation environments [Chapter 4

    Science.gov (United States)

    Douglass F. Jacobs; Thomas D. Landis; Tara Luna

    2009-01-01

    An understanding of all factors influencing plant growth in a nursery environment is needed for the successful growth and production of high-quality container plants. Propagation structures modify the atmospheric conditions of temperature, light, and relative humidity. Native plant nurseries are different from typical horticultural nurseries because plants must be...

  14. Influence of humidity on the thermal behavior of aluminum nanopowders

    International Nuclear Information System (INIS)

    Li Ying; Song Wulin; Xie Changsheng; Zeng Dawen; Wang Aihua; Hu Mulin

    2006-01-01

    Aluminum (Al) nanopowders have increasingly gained attention because of their potential incorporation in explosive and propellant mixtures. This paper reports on a qualitative study on influence of humidity on the thermal behavior of Al nanopowders and the oxidation of aluminum nanoparticles containing a passivating oxide coating. The thermal behaviors were identified by DSC-TG, and Al nanopowders were examined using high-resolution transmission electron microscopy (HRTEM) to understand the stability of the oxide coating in aluminum nanoparticles. It was found that the diameter of Al nanoparticles was in range of 10-100 nm. The original Al nanoparticles were covered by a 3 nm thick compact amorphous oxide layer. After stored for 8 weeks, the oxide layer grew up to 5 nm thick, and the oxidation diffused to the interior of Al nanoparticles. The results indicate that the reactivity of Al nanopowders is deeply influenced by the environment, especially the humidity. The higher relative humidity would accelerate the aging of the Al nanopowders. The DSC-TG results show the oxidation of Al nanoparticles occurs at least in two steps

  15. The sensitivity to humidity of radon monitoring instruments

    International Nuclear Information System (INIS)

    Schmied, H.

    1984-01-01

    In a project funded by the Swedish Building Research Council (BFR) a continuous radon monitoring instrument (RGA-400 EDA Instr. Inc.) with electrostatic field collection has been calibrated. The original calibration factor gave no reliable radon readings and was therefore corrected for relative humidity by EDA. From four calibrations in the radon chamber at the Swedish Radiation Protection Board (SSI) it was clear that the instrument was sensitive to absolute humidity, which gave better agreement than relative humidity or temperature. Sensitivity to humidity for this principle of measure ment has been presented in various papers without presenting any combined influence with temperature, which can lead to the wrong conclusions, especially when the temperature levels differ. Some laboratories use humidity absorbants to overcome this humidity dependence. In this paper the calibration results for the FGA-400 radon readings only, are presented. (Author)

  16. Advancements in accuracy of the alanine dosimetry system. Part 1. The effects of environmental humidity

    International Nuclear Information System (INIS)

    Sleptchonok, Olga F.; Nagy, Vitaly; Desrosiers, Marc F.

    2000-01-01

    A one-year study of the EPR signal of γ-irradiated ( 60 Co) L-α-alanine with simultaneous monitoring of the cavity Q-factor was undertaken. The widespread opinion that the EPR signal remains absolutely stable under normal laboratory storage conditions is inaccurate. At 0% humidity, the signal can be regarded as stable within ±1% of its initial value for 6 months for 1 and 10 kGy doses, but for only 3 months for 100 kGy. When stored at the same relative humidity values up to 60%, the fading rates for dosimeters irradiated to 1 and 10 kGy are similar, whereas signals of dosimeters irradiated to 100 kGy fade considerably faster for all humidities. The rates of fading increase with the relative humidity, especially above 60% R. H. Environmental humidity also deteriorates the accuracy of alanine dosimetry by changing the resonant cavity Q-factor. This is particularly important when irradiated alanine dosimeters are used as instrument calibration standards. Short-term changes in alanine EPR signal amplitudes were recorded upon removal of the irradiated dosimeters from their storage environments. The importance of an in situ standard to correct for measurement errors due to environmental effects is demonstrated. (author)

  17. The effect of Co-doping on the humidity sensing properties of ordered mesoporous TiO2

    Science.gov (United States)

    Li, Zhong; Haidry, Azhar Ali; Gao, Bin; Wang, Tao; Yao, ZhengJun

    2017-08-01

    Monitoring of humidity is of utmost importance as it is essential part of almost every process in our life. Many commercial humidity sensors based on metal oxide semiconductors are available in the market, but there is still need to synthesize low-cost, fast and highly sensitive humidity sensors with no interference from background environment. The aim of this work was to fabricate the ordered mesoporous un-doped and Co-doped TiO2 (0.1-5 mol% Co) and to analyze its humidity sensing properties at room temperatures. The ordered mesoporous powders with high specific surface area (SSA) were prepared by multicomponent self-assembly procedure and then spray-coated onto the sensor substrates with interdigitated gold electrodes. The sensors exhibited excellent stability and reproducible resistance change under various relative humidity percentages (9-90% RH) with negligible effect of background environment. For instance, the response to 90% RH at room temperature was about five orders of magnitude (∼1.39 × 105) and the response time (Tres) was ∼24 s. The reaction/recovery times of the sensors were compared with commercial humidity sensor to show that the reaction times in this work are not given by the surface reaction of water vapor on the sensor surfaces, rather these are mainly influenced by the experimental setup. The sensor response increased up to 3 mol% Co-contents and then decreased for 5 mol% Co-contents. Based on the experimental results, the surface reaction of humidity is discussed related to specific surface area, average grain size and cobalt contents to understand the humidity sensing mechanism.

  18. Degradation testing and failure analysis of DC film capacitors under high humidity conditions

    DEFF Research Database (Denmark)

    Wang, Huai; Nielsen, Dennis Achton; Blaabjerg, Frede

    2015-01-01

    Metallized polypropylene film capacitors are widely used for high-voltage DC-link applications in power electronic converters. They generally have better reliability performance compared to aluminum electrolytic capacitors under electro-thermal stresses within specifications. However......, the degradation of the film capacitors is a concern in applications exposed to high humidity environments. This paper investigates the degradation of a type of plastic-boxed metallized DC film capacitors under different humidity conditions based on a total of 8700 h of accelerated testing and also post failure...... of interest is also presented. The study enables a better understanding of the humidity-related failure mechanisms and reliability performance of DC film capacitors for power electronics applications....

  19. Investigation of Comfort Temperature and Occupant Behavior in Japanese Houses during the Hot and Humid Season

    Directory of Open Access Journals (Sweden)

    Hom B. Rijal

    2014-08-01

    Full Text Available In order to clarify the comfort temperature and to investigate the behavioral adaptation in Japanese houses, we have conducted a thermal comfort survey and occupant behavior survey in 30 living rooms during the hot and humid season in the Kanto region of Japan. We collected 3991 votes from 52 subjects. The comfort temperature was predicted by Griffiths’ method. They are analyzed according to humidity levels and compared with the adaptive model. The logistic regression analysis was conducted in order to understand occupant behavior. The mean comfort temperature in naturally ventilated mode is 27.6 °C which is within the acceptable zone of the adaptive model. The comfort temperature is related with skin moisture sensation. The results showed that the residents adapt to the hot and humid environments by increasing the air movement using behavioral adaptation such as window opening and fan use.

  20. The midday depression of CO2 assimilation in leaves of Arbutus unedo L.: diurnal changes in photosynthetic capacity related to changes in temperature and humidity.

    Science.gov (United States)

    Raschke, K; Resemann, A

    1986-09-01

    Parts of attached leaves of the sclerophyllous shrub Arbutus unedo were subjected to simulated mediterranean days. Gas exchange was recorded in order to recognize the causes of the midday depression in CO2 assimilation. Depressions could be induced in part of a leaf: they were local responses. The CO2-saturation curves of photosynthesis, determined during the morning and afternoon maxima of CO2 assimilation and during the minimum at midday, established that depressions in CO2 assimilation were in one-half of the investigated cases totally caused by reversible reductions in the photosynthetic capacity of the leaves, and in the other half almost totally caused by such reductions. An analysis of 37 daily courses showed that morning reductions and afternoon recoveries of stomatal conductance and rate of photosynthesis occurred simultaneously and in proportion to each other, with the result that the partial pressure of CO2 in the intercellular spaces remained more or less constant. Midday depressions occurred also in detached leaves standing in water. The initiation of a midday depression was not caused by a circadian rhythm, nor was high quantum flux or high temperature a requirement. There was no correlation between the rate of water loss from the leaves, or the amount of water lost, with the degree of reduction of the photosynthetic capacity. However, depressions occurred if an apparent threshold in the water-vapor pressure difference between leaf and air was exceeded. This critical value varied between about 20 and 30 mbar, depending on the leaf investigated. The dominating role of humidity in the induction of the midday depression was further demonstrated when leaf temperature was held constant and the vapor-pressure difference was made to follow the pattern of the mediterranean day: depressions occurred. Depressions however were hardly noticeable when the water-vapor pressure difference was held constant and leaf temperature was allowed to vary. In another set of

  1. Synthesis and Characterization of Nafion-SiO2 Composite Membranes as an Electrolyte for Medium Temperature and Low Relative Humidity

    Directory of Open Access Journals (Sweden)

    Mahreni Mahreni

    2011-12-01

    Full Text Available The weakness of the Nafion membrane as electrolyte of PEMFC associated with physical properties that is easy to shrink at temperatures above 80°C due to dehydration. Shrinkage will decrease the conductivity and membrane damage. Nafion-SiO2 composite membranes can improve membrane stability. The role of SiO2 in the Nafion clusters is as water absorbent cause the membrane remains wet at high temperatures and low humidity and conductivity remains high. The results showed the content of 2.8 wt% of SiO2 in the Nafion membrane, the conductivity of composite membrane is higher than the pure Nafion membrane that are 0.127 S cm-1 in dry conditions and 0.778 S cm-1 in wet conditions at room temperature. Compared with the pure Nafion membrane conductivity are 0.0661 S cm-1 and 0.448 S cm-1 respectively in dry and wet conditions.

  2. Data relating to the environment 1986/87

    International Nuclear Information System (INIS)

    1986-01-01

    'Data relating to the environment' is a work of reference containing in concentrated form a large number of so far individually published data presented as sets of information and mostly arranged in graphic form. This facilitates also the interlinking of data from different fields. The data are divided according to ten subject categories: 1) data on energy and national economy; 2) nature and landscape; 3) soil; 4) forest; 5) air; 6) water; 7) refuse; 8) noise; 9) radioactivity; 10) food. They do not constitute an environmental quality report. For the sector radioactivity not only emission and immission data were compiled, but also the measuring networks for monitoring natural radiation exposure and many measuring values from air, soil and waters for the year 1984 respectively for the period from 1960 to 1984 are indicated. (orig./PW) [de

  3. Data relating to the environment 1988/89

    International Nuclear Information System (INIS)

    1989-01-01

    'Data relating to the environment' is a work of reference containing in concentrated form a large number of so far individually published data presented as sets of information and mostly arranged in graphic form. This facilitates also the interlinking of data from different fields. The data are divided according to ten subject categories: 1) data on energy and national economy; 2) nature and landscape; 3) soil; 4) forest; 5) air; 6) water; 7) refuse; 8) noise; 9) radioactivity, 10) food. They do not constitute an environmental quality report. For the sector radioactivity not only emission and immission data were compiled, but also the measuring networks for monitoring natural radiation exposure and many measuring values from air, soil and waters are indicated. (orig./HP) [de

  4. Data relating to the environment 1984. 2. rev. ed.

    International Nuclear Information System (INIS)

    Augustin, K.; Fischer, D.; Holz, A.; Kumm, A.; Langer, H.

    1984-01-01

    'Data relating to the environment' is a work of reference containing in concentrated form a large number of so far individually published data presented as sets of information and mostly arranged in graphic form. This facilitates also the interlinking of data from different fields. The data are divided according to ten subject categories: 1) data on energy and national economy; 2) nature and landscape; 3) soil; 4) forest; 5) air; 6) water; 7) refuse; 8) noise; 9) radioactivity; 10) food. They do not constitute an environmental quality report. For the sector radioactivity not only emission and immission data were compiled but also the measuring networks for monitoring natural radiation exposure and many measuring values from air, soil and waters for the year 1980 respectively for the period from 1960 to 1980 are indicated. (HP) [de

  5. Influence of air humidity on polymeric microresonators

    International Nuclear Information System (INIS)

    Schmid, S; Kühne, S; Hierold, C

    2009-01-01

    The influence of air humidity on polymeric microresonators is investigated by means of three different resonator types. SU-8 microbeams, SU-8 microstrings and a silicon micromirror with SU-8 hinges are exposed to relative humidities between 3% and 60%. The shifts of the resonant frequencies as a function of the relative humidity (RH) are explained based on mechanical models which are extended with water absorption models in polymer materials. The dominant effect causing the resonant frequency change is evaluated for each structure type. The eigenfrequency of the microstrings and the micromirror in the out-of-plane mode, which both mainly are defined by the pre-stress of the polymeric structures, are found to be highly sensitive to changes of air humidity. The humidity-induced (hygrometric) volume expansion reversibly reduces the pre-stress which results in relative frequency changes of up to 0.78%/%RH for the microstrings. A maximum coefficient of humidity-induced volume expansion for SU-8 of α hyg = 52.3 ppm/%RH is evaluated by fitting the data with the analytical model. It was found that microstrings that were stored at 150 °C over 150 h are more moisture sensitive compared to structures that were stored at room temperature. For the SU-8 microbeams and the micromirror in the tilt mode, the eigenfrequency is mainly defined by the modulus of the polymer material. The measured relative resonant frequency changes were below 1% for the given RH range. For low RH values, antiplasticization is observed (the modulus increases) followed by a plasticization for increasing RH values

  6. Shallow Land Burial Technology - Humid

    International Nuclear Information System (INIS)

    Davis, E.C.; Spalding, B.P.; Lee, S.Y.

    1983-01-01

    The Shallow Land Burial Technology - Humid Project is being conducted for the Department of Energy Low-Level Waste Management Program with the objective of identifying and demonstrating improved technology for disposing of low-level solid waste in humid environments. Two improved disposal techniques are currently being evaluated using nine demonstration trenches at the Engineered Test Facility (ETF). The first is use of a cement-bentonite grout applied as a waste backfill material prior to trench closure and covering. The second is complete hydrologic isolation of waste by emplacement in a trench that is lined on all four sides, top and bottom using synthetic impermeable lining material. An economic analysis of the trench grouting and lining demonstration favored the trench lining operation ($1055/demonstration trench) over trench grouting ($1585/demonstration trench), with the cost differential becoming even greater (as much as a factor of 6 in favor of lining for typical ORNL trenches) as trench dimensions increase and trench volumes exceed those of the demonstration trenches. In addition to the evaluation of trench grouting and lining, major effort has centered on characterization of the ETF site. Though only a part of the overall study, characterization is an extremely important component of the site selection process; it is during these activities that potential problems, which may obviate the site from further consideration, are found. Characterization of the ETF has included studies of regional and site-specific geology, the physical and chemical properties of the soils in which the demonstration trenches are located, and hydrology of the small watershed of which the ETF is a part. 12 references, 6 figures, 2 tables

  7. Humidity effects on wire insulation breakdown strength.

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, Leah

    2013-08-01

    Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

  8. A CMOS Humidity Sensor for Passive RFID Sensing Applications

    Science.gov (United States)

    Deng, Fangming; He, Yigang; Zhang, Chaolong; Feng, Wei

    2014-01-01

    This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 μW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs. PMID:24841250

  9. A CMOS Humidity Sensor for Passive RFID Sensing Applications

    Directory of Open Access Journals (Sweden)

    Fangming Deng

    2014-05-01

    Full Text Available This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 µW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs.

  10. A CMOS humidity sensor for passive RFID sensing applications.

    Science.gov (United States)

    Deng, Fangming; He, Yigang; Zhang, Chaolong; Feng, Wei

    2014-05-16

    This paper presents a low-cost low-power CMOS humidity sensor for passive RFID sensing applications. The humidity sensing element is implemented in standard CMOS technology without any further post-processing, which results in low fabrication costs. The interface of this humidity sensor employs a PLL-based architecture transferring sensor signal processing from the voltage domain to the frequency domain. Therefore this architecture allows the use of a fully digital circuit, which can operate on ultra-low supply voltage and thus achieves low-power consumption. The proposed humidity sensor has been fabricated in the TSMC 0.18 μm CMOS process. The measurements show this humidity sensor exhibits excellent linearity and stability within the relative humidity range. The sensor interface circuit consumes only 1.05 µW at 0.5 V supply voltage and reduces it at least by an order of magnitude compared to previous designs.

  11. 40 CFR 1065.670 - NOX intake-air humidity and temperature corrections.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false NOX intake-air humidity and... NOX intake-air humidity and temperature corrections. See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX intake...

  12. Relation between local food environments and obesity among adults

    Directory of Open Access Journals (Sweden)

    Raine Kim D

    2009-06-01

    Full Text Available Abstract Background Outside of the United States, evidence for associations between exposure to fast-food establishments and risk for obesity among adults is limited and equivocal. The purposes of this study were to investigate whether the relative availability of different types of food retailers around people's homes was associated with obesity among adults in Edmonton, Canada, and if this association varied as a function of distance between food locations and people's homes. Methods Data from a population health survey of 2900 adults (18 years or older conducted in 2002 was linked with geographic measures of access to food retailers. Based upon a ratio of the number of fast-food restaurants and convenience stores to supermarkets and specialty food stores, a Retail Food Environment Index (RFEI was calculated for 800 m and 1600 m buffers around people's homes. In a series of logistic regressions, associations between the RFEI and the level of obesity among adults were examined. Results The median RFEI for adults in Edmonton was 4.00 within an 800 m buffer around their residence and 6.46 within a 1600 m buffer around their residence. Approximately 14% of the respondents were classified as being obese. The odds of a resident being obese were significantly lower (OR = 0.75, 95%CI 0.59 – 0.95 if they lived in an area with the lowest RFEI (below 3.0 in comparison to the highest RFEI (5.0 and above. These associations existed regardless of the covariates included in the model. No significant associations were observed between RFEI within a 1600 m buffer of the home and obesity. Conclusion The lower the ratio of fast-food restaurants and convenience stores to grocery stores and produce vendors near people's homes, the lower the odds of being obese. Thus the proximity of the obesogenic environment to individuals appears to be an important factor in their risk for obesity.

  13. Effect of built environment on tsunami related injuries

    Directory of Open Access Journals (Sweden)

    SD Dharmarathne

    2013-10-01

    Full Text Available Background Built environment is a major determinant in injuries and deaths during natural disasters. Purpose of the present paper was to study the effect of built environment on tsunami injuries.Methods A retrospective residential cohort was constructed one month after the tsunami, based on the cross sectional household survey. Household structure was categorised as a binary variable based on the definition used department of census and statistics for the census.Results The constructed cohort consisted of 4178 individuals, 2143 (51.3% males and 2034 (48.7% females from 1047 households. Mean age of the study sample was 25 years with a standard deviation of 17 years. Out of the 4178 study units studied, 43 (1.1% died during the acute incidence and 19(0.5% died later due to complications. Twenty eight (0.7% people were reported missing at the time of data collection. Moderate to severe injuries were reported by 508 individuals (12.5%. To investigate the injury incidence all tsunami related deaths, missing personals and injuries were classified in to a single group as injuries. Reported number of injuries were 302 (14.4%, and 296 (14.9% among males and females respectively. In multivariate analysis, living in a temporary shelter (OR=0.259, 95% CI 0.351-0.797 shown a protective effect on injuries whereas, residing within the 100 meter boundary from sea (OR 1.43, 95% CI 1.1-1.8 and destruction of house (OR 1.53 95% CI 1.14-2.07 were predictors of injuries.Conclusion Policies on building construction in coastal areas should be done considering these findings to mitigate the effect of future disasters.

  14. Testing high brightness LEDs relative to application environment

    Science.gov (United States)

    Singer, Jeffrey; Mangum, Scott; Lundberg, John

    2006-08-01

    Application of light emitting diodes is expanding as the luminous output and efficiencies of these devices improve. At the same time, the number of LED package types is increasing, making it challenging to determine the appropriate device for use in lighting product designs. A range of factors should be considered when selecting a LED for an application including color coordinates, luminous efficacy, cost, lumen maintenance, application life, packaging and manufacturability. Additional complexities can be introduced as LED packages become obsolete and replacement parts must be selected. The replacement LED characteristics must be understood and assessed against the parameters of the original device, in order to determine if the change will be relatively simple or will force other end-product changes. While some characteristics are readily measured and compared, other factors, such as lumen maintenance, are difficult to verify. This paper will discuss the characteristics of a LED that should be considered during the design process as well as methods to validate these characteristics, particularly those which are not typically on data sheets or, are critical to the design and warrant additional validation. Particular attention will be given to LED lumen maintenance. While published manufacturer data typically provides temperature versus performance curves, the data may not be useful depending upon the application's operating environment. Models must be created to estimate the LED's junction temperature and degradation curve at the applied temperature in order to develop a more precise life estimate. This paper presents one approach to a LED device life and performance study designed with application environments in mind.

  15. All-Optical Graphene Oxide Humidity Sensors

    Directory of Open Access Journals (Sweden)

    Weng Hong Lim

    2014-12-01

    Full Text Available The optical characteristics of graphene oxide (GO were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.

  16. All-optical graphene oxide humidity sensors.

    Science.gov (United States)

    Lim, Weng Hong; Yap, Yuen Kiat; Chong, Wu Yi; Ahmad, Harith

    2014-12-17

    The optical characteristics of graphene oxide (GO) were explored to design and fabricate a GO-based optical humidity sensor. GO film was coated onto a SU8 polymer channel waveguide using the drop-casting technique. The proposed sensor shows a high TE-mode absorption at 1550 nm. Due to the dependence of the dielectric properties of the GO film on water content, this high TE-mode absorption decreases when the ambient relative humidity increases. The proposed sensor shows a rapid response (<1 s) to periodically interrupted humid air flow. The transmission of the proposed sensor shows a linear response of 0.553 dB/% RH in the range of 60% to 100% RH.

  17. Improving stomatal functioning at elevated growth air humidity: A review.

    Science.gov (United States)

    Fanourakis, Dimitrios; Bouranis, Dimitrios; Giday, Habtamu; Carvalho, Dália R A; Rezaei Nejad, Abdolhossein; Ottosen, Carl-Otto

    2016-12-01

    Plants grown at high relative air humidity (RH≥85%) are prone to lethal wilting upon transfer to conditions of high evaporative demand. The reduced survival of these plants is related to (i) increased cuticular permeability, (ii) changed anatomical features (i.e., longer pore length and higher stomatal density), (iii) reduced rehydration ability, (iv) impaired water potential sensitivity to leaf dehydration and, most importantly, (v) compromised stomatal closing ability. This review presents a critical analysis of the strategies which stimulate stomatal functioning during plant development at high RH. These include (a) breeding for tolerant cultivars, (b) interventions with respect to the belowground environment (i.e., water deficit, increased salinity, nutrient culture and grafting) as well as (c) manipulation of the aerial environment [i.e., increased proportion of blue light, increased air movement, temporal temperature rise, and spraying with abscisic acid (ABA)]. Root hypoxia, mechanical disturbance, as well as spraying with compounds mimicking ABA, lessening its inactivation or stimulating its within-leaf redistribution are also expected to improve stomatal functioning of leaves expanded in humid air. Available evidence leaves little doubt that genotypic and phenotypic differences in stomatal functioning following cultivation at high RH are realized through the intermediacy of ABA. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. Attribution of observed surface humidity changes to human influence.

    Science.gov (United States)

    Willett, Katharine M; Gillett, Nathan P; Jones, Philip D; Thorne, Peter W

    2007-10-11

    Water vapour is the most important contributor to the natural greenhouse effect, and the amount of water vapour in the atmosphere is expected to increase under conditions of greenhouse-gas-induced warming, leading to a significant feedback on anthropogenic climate change. Theoretical and modelling studies predict that relative humidity will remain approximately constant at the global scale as the climate warms, leading to an increase in specific humidity. Although significant increases in surface specific humidity have been identified in several regions, and on the global scale in non-homogenized data, it has not been shown whether these changes are due to natural or human influences on climate. Here we use a new quality-controlled and homogenized gridded observational data set of surface humidity, with output from a coupled climate model, to identify and explore the causes of changes in surface specific humidity over the late twentieth century. We identify a significant global-scale increase in surface specific humidity that is attributable mainly to human influence. Specific humidity is found to have increased in response to rising temperatures, with relative humidity remaining approximately constant. These changes may have important implications, because atmospheric humidity is a key variable in determining the geographical distribution and maximum intensity of precipitation, the potential maximum intensity of tropical cyclones, and human heat stress, and has important effects on the biosphere and surface hydrology.

  19. The meaning of activities in the dwelling and residential environment : A structural approach in people-environment relations.

    NARCIS (Netherlands)

    Meesters, J.

    2009-01-01

    The dwelling is a central setting in people’s everyday life. People use their dwelling and residential environment for a large variety of activities and purposes. This study systematically relates activities, settings and meanings to improve the insight into people-environment relations. This is

  20. Relationship of bronchodilator response with oxygen pulse and ventilatory threshold in children with asthma: the effect of body composition and progressive aerobic activity in an environment with low humidity

    Directory of Open Access Journals (Sweden)

    Samera Puyan majd

    2015-11-01

    Full Text Available Background: Asthma is a leading cause of chronic illness in children, impacting heavily on their daily complications. The purpose of the present study was to relationship bronchodilator response (BDR with oxygen pulse (OP and ventilatory threshold (VT in asthma children with various body compositions during progressive aerobic activities. Material and Methods: 25 obese children (BMI>25 and %fat>30with asthma(10 subjects, and healthy children (15 subjects  and 25 lean children(BMI<20 and %fat<20 with asthma(13 subjects, and healthy children (7 subjects performed an exercise protocol in a constant temperature environment 2 ± 22 ° C and humidity (5 ± 35%. During exercise, the steady-state levels of cardio-respiratory parameters were measured using gas analyzer (K4B2. Results: The results showed that after a progressive aerobic activity, values peak oxygen consumption(vo2peak ​​, bronchodilator(BDR, oxygen pulse(OP and ventilatory threshold(VT  in lean and obese asthmatic children were lower than in healthy lean and obese children. In addition, lean children with asthma had lower VT and higher VO2peak , OP and BDR values​​, as compared obese asthmatic children. Between BDR and VT in lean and obese asthmatic children an inverse relationship between BDR and OP and a direct link to asthma in obese children and obese asthmatic children, there was a negative relationship non-significant. Conclusion: Compared with lean children, asthma, obesity as an additional load will affect lung function and increase the pressure on childhood asthma. Therefore, we can accept that obesity may limit performance of exercise in childhood asthma.

  1. Impact of oil and related chemicals on the marine environment

    International Nuclear Information System (INIS)

    1993-01-01

    This review updates a previous review entitled ''Impact of Oil on the Marine Environment''. It covers oil and individual hydrocarbons, used lubricating oils, chemical control agents for oil spills, and wastes from offshore petroleum operations. It considers all major knowledge generated since the mid-1970s. The review covers its topics comprehensively, from a consideration of the composition, sources and inputs of oil to its ecological and human health effects and its effects on man's use of the sea. The review addresses several key questions on the present levels of contamination, the impact of hydrocarbons and related chemicals on marine biota, the recovery potential of marine ecosystems exposed to these contaminants, the degree of protection required for marine ecosystems known to be vulnerable and sensitive, and recommended research and other actions to fill gaps in knowledge. The review describes the hazards of marine oil pollution and associated chemicals and wastes as they are understood currently, and clarifies the importance of reducing oil inputs in coastal and offshore waters. It assists in considering fundamental questions, asked by the public and decision-makers alike, such as: how much oil is entering our oceans, and how much harm is it doing? (author)

  2. Impact of individually controlled facially applied air movement on perceived air quality at high humidity

    DEFF Research Database (Denmark)

    Skwarczynski, Mariusz; Melikov, Arsen Krikor; Kaczmarczyk, J.

    2010-01-01

    and local air velocity under a constant air temperature of 26 degrees C, namely: 70% relative humidity without air movement, 30% relative humidity without air movement and 70% relative humidity with air movement under isothermal conditions. Personalized ventilation was used to supply room air from the front...

  3. Effect of humidity on thoron adsorption in activated charcoal bed

    International Nuclear Information System (INIS)

    Sudeep Kumara, K.; Karunakara, N.; Yashodhara, I.; Sapra, B.K.; Sahoo, B.K.; Gaware, J.J.; Kanse, S.D.; Mayya, Y.S.

    2014-01-01

    Activated charcoal is a well-known adsorber of 222 Rn and 220 Rn gases. This property can be effectively used for remediation of these gases in the workplaces of uranium and thorium processing facilities. However, the adsorption on charcoal is sensitive to variation in temperature and humidity. The successful designing and characterization of adsorption systems require an adequate understanding of these sensitivities. The study has been carried out towards this end, to delineate the effect of relative humidity on the efficacy of 220 Rn mitigations in a charcoal bed. Air carrying 220 Rn from a Pylon source was passed through a column filled with coconut shell-based granular activated charcoal. The relative humidity of the air was controlled, and the transmission characteristics were examined at relative humidity varying from 45% to 60%. The mitigation factor was found to decrease significantly with an increase of humidity in the air. (author)

  4. Adoptive Family Adjustment and Its Relation to Perceived Family Environment.

    Science.gov (United States)

    Martin, Betty; Kelly, Mary Margaret; Towner-Thyrum, Elizabeth

    1999-01-01

    Interviewed adopted college students regarding perceptions of adoptive family life. Found that overall satisfaction with adoptive status and family life was the strongest predictor of perceived general family environment. Perception of adoptive parents' communication styles predicted different aspects of family environment. Acknowledgment of life…

  5. Effect of relative humidity on soot - secondary organic aerosol mixing: A case study from the Soot Aerosol Aging Study (PNNL-SAAS)

    Science.gov (United States)

    Sharma, N.; China, S.; Zaveri, R. A.; Shilling, J. E.; Pekour, M. S.; Liu, S.; Aiken, A. C.; Dubey, M. K.; Wilson, J. M.; Zelenyuk, A.; OBrien, R. E.; Moffet, R.; Gilles, M. K.; Gourihar, K.; Chand, D.; Sedlacek, A. J., III; Subramanian, R.; Onasch, T. B.; Laskin, A.; Mazzoleni, C.

    2014-12-01

    Atmospheric processing of fresh soot particles emitted by anthropogenic as well as natural sources alters their physical and chemical properties. For example, fresh and aged soot particles interact differently with incident solar radiation, resulting in different overall radiation budgets. Varying atmospheric chemical and meteorological conditions can result in complex soot mixing states. The Soot Aerosol Aging Study (SAAS) was conducted at the Pacific Northwest National Laboratory in November 2013 and January 2014 as a step towards understanding the evolution of mixing state of soot and its impact on climate-relevant properties. Aging experiments on diesel soot were carried out in a controlled laboratory chamber, and the effects of condensation and coagulation processes were systematically explored in separate sets of experiments. In addition to online measurement of aerosol properties, aerosol samples were collected for offline single particle analysis to investigate the evolution of the morphology, elemental composition and fine structure of sample particles from different experiments. Condensation experiments focused on the formation of α-pinene secondary organic aerosol on diesel soot aerosol seeds. Experiments were conducted to study the aging of soot under dry (RH < 2%) and humid conditions (RH ~ 80%). We present an analysis of the morphology of soot, its evolution, and its correlation with optical properties, as the condensation of α-pinene SOA is carried out for the two different RH conditions. The analysis was performed by using scanning electron microscopy, transmission electron microscopy, scanning transmission x-ray microscopy and atomic force microscopy for single particle characterization. In addition, particle size, mass, composition, shape, and density were characterized in-situ, as a function of organics condensed on soot seeds, using single particle mass spectrometer.

  6. Biochars as Innovative Humidity Sensing Materials

    Directory of Open Access Journals (Sweden)

    Daniele Ziegler

    2017-12-01

    Full Text Available In this work, biochar-based humidity sensors were prepared by drop-coating technique. Polyvinylpyrrolidone (PVP was added as an organic binder to improve the adhesion of the sensing material onto ceramic substrates having platinum electrodes. Two biochars obtained from different precursors were used. The sensors were tested toward relative humidity (RH at room temperature and showed a response starting around 5 RH%, varying the impedance of 2 orders of magnitude after exposure to almost 100% relative humidity. In both cases, biochar materials are behaving as p-type semiconductors under low amounts of humidity. On the contrary, for higher RH values, the impedance decreased due to water molecules adsorption. When PVP is added to SWP700 biochar, n-p heterojunctions are formed between the two semiconductors, leading to a higher sensitivity at low RH values for the sensors SWP700-10% PVP and SWP700-20% PVP with respect to pure SWP700 sensor. Finally, response and recovery times were both reasonably fast (in the order of 1 min.

  7. Data relating to the environment 1992/93

    International Nuclear Information System (INIS)

    1994-01-01

    This publication contains the environmentally relevant data collected by many Federal and State institutions, associations and international organisations. Data on emissions, waste, consumption of ressources and production give information on environmental pollution and hazards; data on immission, quality and efficiency describe the consequences of anthropological pollution of the environment. Data on measures, cost of environmental pollution and usefulnesss of environmental protection highlight and evaluate the reaction of society to pollution and changes of the environment. The annex of this comprehensive collection contains an overview of available reports from federal and state governments and municipalities on the situation of environment and nature as well as a literature list and a glossary. (orig.) [de

  8. Humid microclimates within the plumage of mallard ducks (Anas platyrhynchos) can potentially facilitate long distance dispersal of propagules

    Science.gov (United States)

    Coughlan, Neil E.; Kelly, Tom C.; Davenport, John; Jansen, Marcel A. K.

    2015-05-01

    Birds as carriers of propagules are major agents in the dispersal of plants, animals, fungi and microbes. However, there is a lack of empirical data in relation to bird-mediated, epizoochorous dispersal. The microclimate found within the plumage likely plays a pivotal role in survival during flight conditions. To investigate the potential of epizoochory, we have analysed the microclimatic conditions within the plumage of mallard ducks (Anas platyrhynchos). Under similar ambient conditions of humidity and temperature, a sample of mallards showed a consistent microclimatic regime with variation across the body surface. The highest (mean) temperature and specific humidity occurred between feathers of the postpatagium. The lowest humidity was found between feathers of the centre back and the lowest temperature in the crissum. Observed differences in plumage depth and density, and distance from the skin, are all likely to be determining factors of microclimate condition. Specific humidity found within the plumage was on average 1.8-3.5 times greater than ambient specific humidity. Thus, the plumage can supply a microclimate buffered from that of the exterior environment. Extrapolating survival data for Lemna minor desiccation at various temperature and humidity levels to the measured plumage microclimatic conditions of living birds, survival for up to 6 h can be anticipated, especially in crissum, crural and breast plumage. The results are discussed in the context of potential long distance epizoochorous dispersal by A. platyrhynchos and similar species.

  9. Humidity sensing in insects-from ecology to neural processing.

    Science.gov (United States)

    Enjin, Anders

    2017-12-01

    Humidity is an omnipresent climatic factor that influences the fitness, reproductive behavior and geographic distribution of animals. Insects in particular use humidity cues to navigate the environment. Although the sensory neurons of this elusive sense were first described more than fifty years ago, the transduction mechanism of humidity sensing (hygrosensation) remains unknown. Recent work has uncovered some of the key molecules involved, opening up for novel approaches to study hygrosensory transduct