Automatic dew-point temperature sensor.

PubMed

Graichen, H; Rascati, R; Gonzalez, R R

1982-06-01

A device is described for measuring dew-point temperature and water vapor pressure in small confined areas. The method is based on the deposition of water on a cooled surface when at dew-point temperature. A small Peltier module lowers the temperature of two electrically conductive plates. At dew point the insulating gap separating the plates becomes conductive as water vapor condenses. Sensors based on this principle can be made small and rugged and can be used for measuring directly the local water vapor pressure. They may be installed within a conventional ventilated sweat capsule used for measuring water vapor loss from the skin surface. A novel application is the measurement of the water vapor pressure gradients across layers of clothing worn by an exercising subject.

An Investigation of the Relation Between Contact Thermometry and Dew-Point Temperature Realization

NASA Astrophysics Data System (ADS)

Benyon, R.; Böse, N.; Mitter, H.; Mutter, D.; Vicente, T.

2012-09-01

Precision optical dew-point hygrometers are the most commonly used transfer standards for the comparison of dew-point temperature realizations at National Metrology Institutes (NMIs) and for disseminating traceability to calibration laboratories. These instruments have been shown to be highly reproducible when properly used. In order to obtain the best performance, the resistance of the platinum resistance thermometer (PRT) embedded in the mirror is usually measured with an external, traceable resistance bridge or digital multimeter. The relation between the conventional calibration of miniature PRTs, prior to their assembly in the mirrors of state-of-the-art optical dew-point hygrometers and their subsequent calibration as dew-point temperature measurement devices, has been investigated. Standard humidity generators of three NMIs were used to calibrate hygrometers of different designs, covering the dew-point temperature range from -75 °C to + 95 °C. The results span more than a decade, during which time successive improvements and modifications were implemented by the manufacturer. The findings are presented and discussed in the context of enabling the optimum use of these transfer standards and as a basis for determining contributions to the uncertainty in their calibration.

Dew Point Calibration System Using a Quartz Crystal Sensor with a Differential Frequency Method.

PubMed

Lin, Ningning; Meng, Xiaofeng; Nie, Jing

2016-11-18

In this paper, the influence of temperature on quartz crystal microbalance (QCM) sensor response during dew point calibration is investigated. The aim is to present a compensation method to eliminate temperature impact on frequency acquisition. A new sensitive structure is proposed with double QCMs. One is kept in contact with the environment, whereas the other is not exposed to the atmosphere. There is a thermal conductivity silicone pad between each crystal and a refrigeration device to keep a uniform temperature condition. A differential frequency method is described in detail and is applied to calibrate the frequency characteristics of QCM at the dew point of -3.75 °C. It is worth noting that frequency changes of two QCMs were approximately opposite when temperature conditions were changed simultaneously. The results from continuous experiments show that the frequencies of two QCMs as the dew point moment was reached have strong consistency and high repeatability, leading to the conclusion that the sensitive structure can calibrate dew points with high reliability.

Dew-point measurements at high water vapour pressure

NASA Astrophysics Data System (ADS)

Lomperski, S.; Dreier, J.

1996-05-01

A dew-point meter capable of measuring humidity at high vapour pressure and high temperature has been constructed and tested. Humidity measurements in pure steam were made over the temperature range 100 - 1500957-0233/7/5/003/img1C and a vapour pressure range of 1 - 4 bar. The dew-point meter performance was assessed by comparing measurements with a pressure transmitter and agreement between the two was within 0957-0233/7/5/003/img2% relative humidity. Humidity measurements in steam - air mixtures were also made and the dew-point meter readings were compared to those of a zirconia oxygen sensor. For these tests the dew-point meter readings were generally within 0957-0233/7/5/003/img2% relative humidity of the oxygen sensor measurements.

A New Primary Dew-Point Generator at TUBITAK UME

NASA Astrophysics Data System (ADS)

Oğuz Aytekin, S.; Karaböce, N.; Heinonen, M.; Sairanen, H.

2018-05-01

An implementation of a new low-range primary humidity generator as a part of an international collaboration between TUBITAK UME and VTT MIKES was initiated as a EURAMET Project Number 1259. The dew-point generator was designed and constructed within the scope of the cooperation between TUBITAK UME and VTT MIKES in order to extend the dew-point temperature measurement capability of Humidity Laboratory of TUBITAK UME down to - 80 °C. The system was thoroughly characterized and validated at TUBITAK UME to support the evidence for dew-point temperature uncertainties. The new generator has a capability of operating in the range of - 80 °C to +10 °C, but at the moment, it was characterized down to - 60 °C. The core of the generator system is a saturator which is fully immersed in a liquid bath. Dry air is supplied to the saturator through a temperature-controlled pre-saturator. The operation of the system is based on the single-pressure generation method with a single pass, i.e., the dew-point temperature is only controlled by the saturator temperature, and the humidity-controlled air is not returned to the system after leaving of the saturator. The metrological performance of the saturator was investigated thoroughly at both National Metrology Institutes. The pre-saturator was also tested using a thermostatic bath at VTT MIKES prior to sending them to TUBITAK UME. This paper describes the principle and design of the generator in detail. The dew-point measurement system and the corresponding uncertainty analysis of the dew-point temperature scale realized with the generator in the range from - 60 °C to 10 °C is also presented.

Estimation of dew point temperature using neuro-fuzzy and neural network techniques

NASA Astrophysics Data System (ADS)

Kisi, Ozgur; Kim, Sungwon; Shiri, Jalal

2013-11-01

This study investigates the ability of two different artificial neural network (ANN) models, generalized regression neural networks model (GRNNM) and Kohonen self-organizing feature maps neural networks model (KSOFM), and two different adaptive neural fuzzy inference system (ANFIS) models, ANFIS model with sub-clustering identification (ANFIS-SC) and ANFIS model with grid partitioning identification (ANFIS-GP), for estimating daily dew point temperature. The climatic data that consisted of 8 years of daily records of air temperature, sunshine hours, wind speed, saturation vapor pressure, relative humidity, and dew point temperature from three weather stations, Daego, Pohang, and Ulsan, in South Korea were used in the study. The estimates of ANN and ANFIS models were compared according to the three different statistics, root mean square errors, mean absolute errors, and determination coefficient. Comparison results revealed that the ANFIS-SC, ANFIS-GP, and GRNNM models showed almost the same accuracy and they performed better than the KSOFM model. Results also indicated that the sunshine hours, wind speed, and saturation vapor pressure have little effect on dew point temperature. It was found that the dew point temperature could be successfully estimated by using T mean and R H variables.

Note: A dual-channel sensor for dew point measurement based on quartz crystal microbalance.

PubMed

Li, Ning; Meng, Xiaofeng; Nie, Jing

2017-05-01

A new sensor with dual-channel was designed for eliminating the temperature effect on the frequency measurement of the quartz crystal microbalance (QCM) in dew point detection. The sensor uses active temperature control, produces condensation on the surface of QCM, and then detects the dew point. Both the single-channel and the dual-channel methods were conducted based on the device. The measurement error of the single-channel method was less than 0.5 °C at the dew point range of -2 °C-10 °C while the dual-channel was 0.3 °C. The results showed that the dual-channel method was able to eliminate the temperature effect and yield better measurement accuracy.

Note: A dual-channel sensor for dew point measurement based on quartz crystal microbalance

NASA Astrophysics Data System (ADS)

Li, Ning; Meng, Xiaofeng; Nie, Jing

2017-05-01

A new sensor with dual-channel was designed for eliminating the temperature effect on the frequency measurement of the quartz crystal microbalance (QCM) in dew point detection. The sensor uses active temperature control, produces condensation on the surface of QCM, and then detects the dew point. Both the single-channel and the dual-channel methods were conducted based on the device. The measurement error of the single-channel method was less than 0.5 °C at the dew point range of -2 °C-10 °C while the dual-channel was 0.3 °C. The results showed that the dual-channel method was able to eliminate the temperature effect and yield better measurement accuracy.

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform.

PubMed

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-07-15

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard "chilled-mirror" dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional "chilled-mirror" hygrometers. Moreover, this DPS outperforms conventional "chilled-mirror" hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints.

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform

NASA Astrophysics Data System (ADS)

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-07-01

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard “chilled-mirror” dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional “chilled-mirror” hygrometers. Moreover, this DPS outperforms conventional “chilled-mirror” hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints.

Dew Point Calibration System Using a Quartz Crystal Sensor with a Differential Frequency Method

PubMed Central

Lin, Ningning; Meng, Xiaofeng; Nie, Jing

2016-01-01

In this paper, the influence of temperature on quartz crystal microbalance (QCM) sensor response during dew point calibration is investigated. The aim is to present a compensation method to eliminate temperature impact on frequency acquisition. A new sensitive structure is proposed with double QCMs. One is kept in contact with the environment, whereas the other is not exposed to the atmosphere. There is a thermal conductivity silicone pad between each crystal and a refrigeration device to keep a uniform temperature condition. A differential frequency method is described in detail and is applied to calibrate the frequency characteristics of QCM at the dew point of −3.75 °C. It is worth noting that frequency changes of two QCMs were approximately opposite when temperature conditions were changed simultaneously. The results from continuous experiments show that the frequencies of two QCMs as the dew point moment was reached have strong consistency and high repeatability, leading to the conclusion that the sensitive structure can calibrate dew points with high reliability. PMID:27869746

Development of measurement simulation of the laser dew-point hygrometer using an optical fiber cable

NASA Astrophysics Data System (ADS)

Matsumoto, Shigeaki

2005-02-01

In order to improve the initial and the response times of the Laser Dew-Point Hygrometer (LDH), the measurement simulation was developed on the basis of the loop computation of the surface temperature of a gold plate for dew depostition, the quantity of deposited dew and the intensity of scattered light from the surface of the plate at time interval of 5 sec during measurement. A more detailed relationship between the surface temperature of the plate and the cooling current, and the time constant of the integrator in the control circuit of the LDH were introduced in the simulation program as a function of atmospheric temperature. The simulation was more close to the actual measurement by the LDH. The simulation results indicated the possibility of improving both the times of teh LDH by the increase of the sensitivity of dew and that of the mass transfer coefficient of dew deposited on the plate surface. It was concluded that the initial and the response times could be improved to below 100sec and 120 sec, respectively in the dew-point range at room temperature, that are almost half of the those times of the original LDH.

Experiment Comparison between Engineering Acid Dew Point and Thermodynamic Acid Dew Point

NASA Astrophysics Data System (ADS)

Song, Jinghui; Yuan, Hui; Deng, Jianhua

2018-06-01

in order to realize the accurate prediction of acid dew point, a set of measurement system of acid dew point for the flue gas flue gas in the tail of the boiler was designed and built, And measured at the outlet of an air preheater of a power plant of 1 000 MW, The results show that: Under the same conditions, with the test temperature decreases, Nu of heat transfer tubes, fouling and corrosion of pipe wall and corrosion pieces gradually deepened. Then, the measured acid dew point is compared with the acid dew point obtained by using the existing empirical formula under the same coal type. The dew point of engineering acid is usually about 40 ° lower than the dew point of thermodynamic acid because of the coupling effect of fouling on the acid liquid, which can better reflect the actual operation of flue gas in engineering and has certain theoretical guidance for the design and operation of deep waste heat utilization system significance.

Temperature distribution model for the semiconductor dew point detector

NASA Astrophysics Data System (ADS)

Weremczuk, Jerzy; Gniazdowski, Z.; Jachowicz, Ryszard; Lysko, Jan M.

2001-08-01

The simulation results of temperature distribution in the new type silicon dew point detector are presented in this paper. Calculations were done with use of the SMACEF simulation program. Fabricated structures, apart from the impedance detector used to the dew point detection, contained the resistive four terminal thermometer and two heaters. Two detector structures, the first one located on the silicon membrane and the second one placed on the bulk materials were compared in this paper.

An ultrahigh-accuracy Miniature Dew Point Sensor based on an Integrated Photonics Platform

PubMed Central

Tao, Jifang; Luo, Yu; Wang, Li; Cai, Hong; Sun, Tao; Song, Junfeng; Liu, Hui; Gu, Yuandong

2016-01-01

The dew point is the temperature at which vapour begins to condense out of the gaseous phase. The deterministic relationship between the dew point and humidity is the basis for the industry-standard “chilled-mirror” dew point hygrometers used for highly accurate humidity measurements, which are essential for a broad range of industrial and metrological applications. However, these instruments have several limitations, such as high cost, large size and slow response. In this report, we demonstrate a compact, integrated photonic dew point sensor (DPS) that features high accuracy, a small footprint, and fast response. The fundamental component of this DPS is a partially exposed photonic micro-ring resonator, which serves two functions simultaneously: 1) sensing the condensed water droplets via evanescent fields and 2) functioning as a highly accurate, in situ temperature sensor based on the thermo-optic effect (TOE). This device virtually eliminates most of the temperature-related errors that affect conventional “chilled-mirror” hygrometers. Moreover, this DPS outperforms conventional “chilled-mirror” hygrometers with respect to size, cost and response time, paving the way for on-chip dew point detection and extension to applications for which the conventional technology is unsuitable because of size, cost, and other constraints. PMID:27417734

Densimetry for the Quantification of Sorption Phenomena on Nonporous Media Near the Dew Point of Fluid Mixtures.

PubMed

Richter, Markus; McLinden, Mark O

2017-07-21

Phase equilibria of fluid mixtures are important in numerous industrial applications and are, thus, a major focus of thermophysical property research. Improved data, particularly along the dew line, are needed to improve model predictions. Here we present experimental results utilizing highly accurate densimetry to quantify the effects of sorption and capillary condensation, which exert a distorting influence on measured properties near the dew line. We investigate the (pressure, density, temperature, composition) behaviour of binary (CH 4  + C 3 H 8 ) and (Ar + CO 2 ) mixtures over the temperature range from (248.15 to 273.15) K starting at low pressures and increasing in pressure towards the dew point along isotherms. Three distinct regions are observed: (1) minor sorption effects in micropores at low pressures; (2) capillary condensation followed by wetting in macro-scale surface scratches beginning approximately 2% below the dew-point pressure; (3) bulk condensation. We hypothesize that the true dew point lies within the second region.

Determination of the dew point and the frost point below 0 degrees C making use of the beta-ray backscattering and the electric conductivity on the narrow surface of insulated layer.

PubMed

Matsumoto, S; Kobayashi, H

1979-10-15

It is necessary to distinguish between the dew point and the frost point below 0 degrees C. The freezing of the dew and the melting of the frost are respectively detected by the rapid decrease and the increase of the conduction current on the narrow surface of insulated layer made of epoxy, 0.5 mm in width and 10 mm in length, on which the dew deposits. The dew point -9 degrees C and the frost point -8 degrees C in the humidity 21% at the temperature 13 degrees C are clearly distinguished in this method.

Hourly predictive Levenberg-Marquardt ANN and multi linear regression models for predicting of dew point temperature

NASA Astrophysics Data System (ADS)

Zounemat-Kermani, Mohammad

2012-08-01

In this study, the ability of two models of multi linear regression (MLR) and Levenberg-Marquardt (LM) feed-forward neural network was examined to estimate the hourly dew point temperature. Dew point temperature is the temperature at which water vapor in the air condenses into liquid. This temperature can be useful in estimating meteorological variables such as fog, rain, snow, dew, and evapotranspiration and in investigating agronomical issues as stomatal closure in plants. The availability of hourly records of climatic data (air temperature, relative humidity and pressure) which could be used to predict dew point temperature initiated the practice of modeling. Additionally, the wind vector (wind speed magnitude and direction) and conceptual input of weather condition were employed as other input variables. The three quantitative standard statistical performance evaluation measures, i.e. the root mean squared error, mean absolute error, and absolute logarithmic Nash-Sutcliffe efficiency coefficient ( {| {{{Log}}({{NS}})} |} ) were employed to evaluate the performances of the developed models. The results showed that applying wind vector and weather condition as input vectors along with meteorological variables could slightly increase the ANN and MLR predictive accuracy. The results also revealed that LM-NN was superior to MLR model and the best performance was obtained by considering all potential input variables in terms of different evaluation criteria.

A Quartz Crystal Microbalance dew point sensor without frequency measurement.

PubMed

Wang, Guohua; Zhang, Weishuo; Wang, Shuo; Sun, Jinglin

2014-11-01

This work deals with the design of a dew point sensor based on Quartz Crystal Microbalance (QCM) without measuring the frequency. This idea is inspired by the fact that the Colpitts oscillation circuit will stop oscillating when the QCM works in the liquid media. The quartz crystal and the electrode are designed through the finite element simulation and the stop oscillating experiment is conducted to verify the sensibility. Moreover, the measurement result is calibrated to approach the true value. At last a series of dew points at the same temperature is measured with the designed sensor. Results show that the designed dew point sensor is able to detect the dew point with the proper accuracy.

A quartz crystal microbalance dew point sensor without frequency measurement

NASA Astrophysics Data System (ADS)

Wang, Guohua; Zhang, Weishuo; Wang, Shuo; Sun, Jinglin

2014-11-01

This work deals with the design of a dew point sensor based on Quartz Crystal Microbalance (QCM) without measuring the frequency. This idea is inspired by the fact that the Colpitts oscillation circuit will stop oscillating when the QCM works in the liquid media. The quartz crystal and the electrode are designed through the finite element simulation and the stop oscillating experiment is conducted to verify the sensibility. Moreover, the measurement result is calibrated to approach the true value. At last a series of dew points at the same temperature is measured with the designed sensor. Results show that the designed dew point sensor is able to detect the dew point with the proper accuracy.

New Primary Dew-Point Generators at HMI/FSB-LPM in the Range from -70 °C to +60 °C

NASA Astrophysics Data System (ADS)

Zvizdic, Davor; Heinonen, Martti; Sestan, Danijel

2012-09-01

To extend the dew-point range and to improve the uncertainties of the humidity scale realization at HMI/FSB-LPM, new primary low- and high-range dew-point generators were developed and implemented in cooperation with MIKES, in 2009 through EUROMET Project No. 912. The low-range saturator is designed for primary realization of the dew-point temperature scale from -70 °C to + 5 °C, while the high-range saturator covers the range from 1 °C to 60 °C. The system is designed as a single-pressure, single-pass dew-point generator. MIKES designed and constructed both the saturators to be implemented in dew-point calibration systems at LPM. The LPM took care of purchasing and adapting liquid baths, of implementing the temperature and pressure measurement equipment appropriate for use in the systems, and development of gas preparation and flow control systems as well as of the computer-based automated data acquisition. The principle and the design of the generator are described in detail and schematically depicted. The tests were performed at MIKES to investigate how close both the saturators are to an ideal saturator. Results of the tests show that both the saturators are efficient enough for a primary realization of the dew-point temperature scale from -70 °C to + 60 °C, in the specified flow-rate ranges. The estimated standard uncertainties due to the non-ideal saturation efficiency are between 0.02 °C and 0.05 °C.

1935-2004 Water Vapor Trends at the Summit of Mount Washington, NH

NASA Astrophysics Data System (ADS)

Seidel, T. M.; Grant, A. N.; Pszenny, A. A.

2005-12-01

As part of an ongoing effort to digitize and analyze the unique historical climate record from the summit of Mount Washington, water vapor mixing ratios calculated from synoptic (six-hourly) sling psychrometer and related data will be presented. The Mount Washington Observatory, located at 44°16'N, 71°18'W, 1914 m ASL, has been recording meteorological conditions since 1932. A continuous record of hourly and synoptic data exists from 1935 to the present. Previous work with hourly temperature data has shown an increase in annual temperature of 0.3°C over this 69-year interval, with larger increases during spring and winter, and a decrease in diurnal temperature range (A. Grant et al., J. Climate, in press). Preliminary examination of the synoptic psychrometric data suggests a decrease in annual dew point of approximately 0.4°C, with larger decreases in fall and winter than during the other seasons. Decreasing dew points are expected under two conditions: drier air or constant water vapor with increasing temperature. Other dew point climatologies of the continental United States for the second half of the 20th century have shown mixed results, with increased dew points evident at some stations, decreased dew points at others, and no clear regional patterns.

Integrated CMOS dew point sensors for relative humidity measurement

NASA Astrophysics Data System (ADS)

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%.

KEY COMPARISON: Final report of APMP.T-K6 (original name APMP-IC-1-97): Comparison of humidity measurements using a dew point meter as a transfer standard

NASA Astrophysics Data System (ADS)

Li, Wang; Takahashi, C.; Hussain, F.; Hong, Yi; Nham, H. S.; Chan, K. H.; Lee, L. T.; Chahine, K.

2007-01-01

This APMP key comparison of humidity measurements using a dew point meter as a transfer standard was carried out among eight national metrology institutes from February 1999 to January 2001. The NMC/SPRING, Singapore was the pilot laboratory and a chilled mirror dew point meter offered by NMIJ was used as a transfer standard. The transfer standard was calibrated by each participating institute against local humidity standards in terms of frost and dew point temperature. Each institute selected its frost/dew point temperature calibration points within the range from -70 °C to 20 °C frost/dew point with 5 °C step. The majority of participating institutes measured from -60 °C to 20 °C frost/dew point and a simple mean evaluation was performed in this range. The differences between the institute values and the simple means for all participating institutes are within two standard deviations from the mean values. Bilateral equivalence was analysed in terms of pair difference and single parameter Quantified Demonstrated Equivalence. The results are presented in the report. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Remotely-sensed, nocturnal, dew point correlates with malaria transmission in Southern Province, Zambia: a time-series study

PubMed Central

2014-01-01

Background Plasmodium falciparum transmission has decreased significantly in Zambia in the last decade. The malaria transmission is influenced by environmental variables. Incorporation of environmental variables in models of malaria transmission likely improves model fit and predicts probable trends in malaria disease. This work is based on the hypothesis that remotely-sensed environmental factors, including nocturnal dew point, are associated with malaria transmission and sustain foci of transmission during the low transmission season in the Southern Province of Zambia. Methods Thirty-eight rural health centres in Southern Province, Zambia were divided into three zones based on transmission patterns. Correlations between weekly malaria cases and remotely-sensed nocturnal dew point, nocturnal land surface temperature as well as vegetation indices and rainfall were evaluated in time-series analyses from 2012 week 19 to 2013 week 36. Zonal as well as clinic-based, multivariate, autoregressive, integrated, moving average (ARIMAX) models implementing environmental variables were developed to model transmission in 2011 week 19 to 2012 week 18 and forecast transmission in 2013 week 37 to week 41. Results During the dry, low transmission season significantly higher vegetation indices, nocturnal land surface temperature and nocturnal dew point were associated with the areas of higher transmission. Environmental variables improved ARIMAX models. Dew point and normalized differentiated vegetation index were significant predictors and improved all zonal transmission models. In the high-transmission zone, this was also seen for land surface temperature. Clinic models were improved by adding dew point and land surface temperature as well as normalized differentiated vegetation index. The mean average error of prediction for ARIMAX models ranged from 0.7 to 33.5%. Forecasts of malaria incidence were valid for three out of five rural health centres; however, with poor results at the zonal level. Conclusions In this study, the fit of ARIMAX models improves when environmental variables are included. There is a significant association of remotely-sensed nocturnal dew point with malaria transmission. Interestingly, dew point might be one of the factors sustaining malaria transmission in areas of general aridity during the dry season. PMID:24927747

Remotely-sensed, nocturnal, dew point correlates with malaria transmission in Southern Province, Zambia: a time-series study.

PubMed

Nygren, David; Stoyanov, Cristina; Lewold, Clemens; Månsson, Fredrik; Miller, John; Kamanga, Aniset; Shiff, Clive J

2014-06-13

Plasmodium falciparum transmission has decreased significantly in Zambia in the last decade. The malaria transmission is influenced by environmental variables. Incorporation of environmental variables in models of malaria transmission likely improves model fit and predicts probable trends in malaria disease. This work is based on the hypothesis that remotely-sensed environmental factors, including nocturnal dew point, are associated with malaria transmission and sustain foci of transmission during the low transmission season in the Southern Province of Zambia. Thirty-eight rural health centres in Southern Province, Zambia were divided into three zones based on transmission patterns. Correlations between weekly malaria cases and remotely-sensed nocturnal dew point, nocturnal land surface temperature as well as vegetation indices and rainfall were evaluated in time-series analyses from 2012 week 19 to 2013 week 36. Zonal as well as clinic-based, multivariate, autoregressive, integrated, moving average (ARIMAX) models implementing environmental variables were developed to model transmission in 2011 week 19 to 2012 week 18 and forecast transmission in 2013 week 37 to week 41. During the dry, low transmission season significantly higher vegetation indices, nocturnal land surface temperature and nocturnal dew point were associated with the areas of higher transmission. Environmental variables improved ARIMAX models. Dew point and normalized differentiated vegetation index were significant predictors and improved all zonal transmission models. In the high-transmission zone, this was also seen for land surface temperature. Clinic models were improved by adding dew point and land surface temperature as well as normalized differentiated vegetation index. The mean average error of prediction for ARIMAX models ranged from 0.7 to 33.5%. Forecasts of malaria incidence were valid for three out of five rural health centres; however, with poor results at the zonal level. In this study, the fit of ARIMAX models improves when environmental variables are included. There is a significant association of remotely-sensed nocturnal dew point with malaria transmission. Interestingly, dew point might be one of the factors sustaining malaria transmission in areas of general aridity during the dry season.

Inventory of File nam.t00z.smartconus06.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 6 hour fcst Dew Point Temperature [K] 003 surface SPFH 6 hour fcst Specific Index [K] 027 surface HINDEX 6 hour fcst Haines Index [Numeric] 028 surface TMP 5 hour fcst Temperature [K] 029 surface TMP 4 hour fcst Temperature [K] 030 surface DPT 5 hour fcst Dew Point Temperature [K

Inventory of File gfs.t06z.smartguam12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific Best (4 layer) Lifted Index [K] 020 surface TMP 11 hour fcst Temperature [K] 021 surface TMP 10 hour fcst Temperature [K] 022 surface DPT 11 hour fcst Dew Point Temperature [K] 023 surface DPT 10 hour

Inventory of File nam.t00z.smartconus12.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 12 hour fcst Dew Point Temperature [K] 003 surface SPFH 12 hour fcst Specific hour fcst Haines Index [Numeric] 030 surface TMP 11 hour fcst Temperature [K] 031 surface TMP 10 hour fcst Temperature [K] 032 surface DPT 11 hour fcst Dew Point Temperature [K] 033 surface DPT 10 hour

A novel method of measuring the concentration of anaesthetic vapours using a dew-point hygrometer.

PubMed

Wilkes, A R; Mapleson, W W; Mecklenburgh, J S

1994-02-01

The Antoine equation relates the saturated vapour pressure of a volatile substance, such as an anaesthetic agent, to the temperature. The measurement of the 'dew-point' of a dry gas mixture containing a volatile anaesthetic agent by a dew-point hygrometer permits the determination of the partial pressure of the anaesthetic agent. The accuracy of this technique is limited only by the accuracy of the Antoine coefficients and of the temperature measurement. Comparing measurements by the dew-point method with measurements by refractometry showed systematic discrepancies up to 0.2% and random discrepancies with SDS up to 0.07% concentration in the 1% to 5% range for three volatile anaesthetics. The systematic discrepancies may be due to errors in available data for the vapour pressures and/or the refractive indices of the anaesthetics.

Inventory of File gfs.t06z.smartguam03.tm00.grib2

Science.gov Websites

Temperature [K] 002 surface DPT 3 hour fcst Dew Point Temperature [K] 003 surface SPFH 3 hour fcst Specific surface 4LFTX 3 hour fcst Best (4 layer) Lifted Index [K] 019 surface TMP 2 hour fcst Temperature [K] 020 surface TMP 1 hour fcst Temperature [K] 021 surface DPT 2 hour fcst Dew Point Temperature [K] 022 surface

A new comparison method for dew-point generators

NASA Astrophysics Data System (ADS)

Heinonen, Martti

1999-12-01

A new method for comparing dew-point generators was developed at the Centre for Metrology and Accreditation. In this method, the generators participating in a comparison are compared with a transportable saturator unit using a dew-point comparator. The method was tested by constructing a test apparatus and by comparing it with the MIKES primary dew-point generator several times in the dew-point temperature range from -40 to +75 °C. The expanded uncertainty (k = 2) of the apparatus was estimated to be between 0.05 and 0.07 °C and the difference between the comparator system and the generator is well within these limits. In particular, all of the results obtained in the range below 0 °C are within ±0.03 °C. It is concluded that a new type of a transfer standard with characteristics most suitable for dew-point comparisons can be developed on the basis of the principles presented in this paper.

Super Clausius-Clapeyron scaling of extreme hourly precipitation and its relation to large-scale atmospheric conditions

NASA Astrophysics Data System (ADS)

Lenderink, Geert; Barbero, Renaud; Loriaux, Jessica; Fowler, Hayley

2017-04-01

Present-day precipitation-temperature scaling relations indicate that hourly precipitation extremes may have a response to warming exceeding the Clausius-Clapeyron (CC) relation; for The Netherlands the dependency on surface dew point temperature follows two times the CC relation corresponding to 14 % per degree. Our hypothesis - as supported by a simple physical argument presented here - is that this 2CC behaviour arises from the physics of convective clouds. So, we think that this response is due to local feedbacks related to the convective activity, while other large scale atmospheric forcing conditions remain similar except for the higher temperature (approximately uniform warming with height) and absolute humidity (corresponding to the assumption of unchanged relative humidity). To test this hypothesis, we analysed the large-scale atmospheric conditions accompanying summertime afternoon precipitation events using surface observations combined with a regional re-analysis for the data in The Netherlands. Events are precipitation measurements clustered in time and space derived from approximately 30 automatic weather stations. The hourly peak intensities of these events again reveal a 2CC scaling with the surface dew point temperature. The temperature excess of moist updrafts initialized at the surface and the maximum cloud depth are clear functions of surface dew point temperature, confirming the key role of surface humidity on convective activity. Almost no differences in relative humidity and the dry temperature lapse rate were found across the dew point temperature range, supporting our theory that 2CC scaling is mainly due to the response of convection to increases in near surface humidity, while other atmospheric conditions remain similar. Additionally, hourly precipitation extremes are on average accompanied by substantial large-scale upward motions and therefore large-scale moisture convergence, which appears to accelerate with surface dew point. This increase in large-scale moisture convergence appears to be consequence of latent heat release due to the convective activity as estimated from the quasi-geostrophic omega equation. Consequently, most hourly extremes occur in precipitation events with considerable spatial extent. Importantly, this event size appears to increase rapidly at the highest dew point temperature range, suggesting potentially strong impacts of climatic warming.

Validation of a dew-point generator for pressures up to 6 MPa using nitrogen and air

NASA Astrophysics Data System (ADS)

Bosma, R.; Mutter, D.; Peruzzi, A.

2012-08-01

A new primary humidity standard was developed at VSL that, in addition to ordinary operation with air and nitrogen at atmospheric pressure, can be operated with other carrier gases such as natural gas at pressures up to 6 MPa and SF6 at pressures up to 1 MPa. The temperature range of the standard is from -80 °C to +20 °C. In this paper, we report the validation of the new primary dew-point generator in the temperature range -41 °C to +5 °C and the pressure range 0.1 MPa to 6 MPa using nitrogen and air. For the validation the flow through the dew-point generator was varied up to 10 l min-1 (at 23 °C and 1013 hPa) and the dew point of the gas entering the generator was varied up to 15 °C above the dew point exiting the generator. The validation results showed that the new generator, over the tested temperature and pressure range, can be used with a standard uncertainty of 0.02 °C frost/dew point. The measurements used for the validation at -41 °C and -20 °C with nitrogen and at +5 °C with air were also used to calculate the enhancement factor at pressures up to 6 MPa. For +5 °C the differences between the measured and literature values were compatible with the respective uncertainties. For -41 °C and -20 °C they were compatible only up to 3 MPa. At 6 MPa a discrepancy was observed.

Future PMPs Estimation in Korea under AR5 RCP 8.5 Climate Change Scenario: Focus on Dew Point Temperature Change

NASA Astrophysics Data System (ADS)

Okjeong, Lee; Sangdan, Kim

2016-04-01

According to future climate change scenarios, future temperature is expected to increase gradually. Therefore, it is necessary to reflect the effects of these climate changes to predict Probable Maximum Precipitations (PMPs). In this presentation, PMPs will be estimated with future dew point temperature change. After selecting 174 major storm events from 1981 to 2005, new PMPs will be proposed with respect to storm areas (25, 100, 225, 400, 900, 2,025, 4,900, 10,000 and 19,600 km2) and storm durations (1, 2, 4, 6, 8, 12, 18, 24, 48 and 72 hours) using the Korea hydro-meteorological method. Also, orographic transposition factor will be applied in place of the conventional terrain impact factor which has been used in previous Korean PMPs estimation reports. After estimating dew point temperature using future temperature and representative humidity information under the Korea Meteorological Administration AR5 RCP 8.5, changes in the PMPs under dew point temperature change will be investigated by comparison with present and future PMPs. This research was supported by a grant(14AWMP-B082564-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

Investigation of potential factors affecting the measurement of dew point temperature in oil-soaked transformers

NASA Astrophysics Data System (ADS)

Kraus, Adam H.

Moisture within a transformer's insulation system has been proven to degrade its dielectric strength. When installing a transformer in situ, one method used to calculate the moisture content of the transformer insulation is to measure the dew point temperature of the internal gas volume of the transformer tank. There are two instruments commercially available that are designed for dew point temperature measurement: the Alnor Model 7000 Dewpointer and the Vaisala DRYCAPRTM Hand-Held Dewpoint Meter DM70. Although these instruments perform an identical task, the design technology behind each instrument is vastly different. When the Alnor Dewpointer and Vaisala DM70 instruments are used to measure the dew point of the internal gas volume simultaneously from a pressurized transformer, their differences in dew point measurement have been observed to vary as much as 30 °F. There is minimal scientific research available that focuses on the process of measuring dew point of a gas inside a pressurized transformer, let alone this observed phenomenon. The primary objective of this work was to determine what effect certain factors potentially have on dew point measurements of a transformer's internal gas volume, in hopes of understanding the root cause of this phenomenon. Three factors that were studied include (1) human error, (2) the use of calibrated and out-of-calibration instruments, and (3) the presence of oil vapor gases in the dry air sample, and their subsequent effects on the Q-value of the sampled gas. After completing this portion of testing, none of the selected variables proved to be a direct cause of the observed discrepancies between the two instruments. The secondary objective was to validate the accuracy of each instrument as compared to its respective published range by testing against a known dew point temperature produced by a humidity generator. In a select operating range of -22 °F to -4 °F, both instruments were found to be accurate and within their specified tolerances. This temperature range is frequently encountered in oil-soaked transformers, and demonstrates that both instruments can measure accurately over a limited, yet common, range despite their different design methodologies. It is clear that there is another unknown factor present in oil-soaked transformers that is causing the observed discrepancy between these instruments. Future work will include testing on newly manufactured or rewound transformers in order to investigate other variables that could be causing this discrepancy.

The effect of water contamination on the dew-point temperature scale realization with humidity generators

NASA Astrophysics Data System (ADS)

Vilbaste, M.; Heinonen, M.; Saks, O.; Leito, I.

2013-08-01

The purpose of this paper is to study the effect of contaminated water in the context of humidity generators. Investigation of different methods to determine the drop in dew-point temperature due to contamination and experiments on actual contamination rates are reported. Different methods for calculating the dew-point temperature effect from electrical conductivity and density measurements are studied with high-purity water and aqueous solutions of NaCl and LiCl. The outcomes of the calculation methods are compared with the results of direct humidity measurements. The results show that the often applied Raoult's law based calculation method is in good agreement with other methods. For studying actual contamination, water samples were kept in glass, plastic, copper and stainless-steel vessels for up to 13 months to investigate natural ionic and organic contamination in vessels with different wall materials. The amount of ionic contamination was found to be higher in copper and glass vessels than in stainless-steel and plastic vessels. The amount of organic contamination was found to be highest in the plastic vessel. In all the cases, however, the corresponding drop in dew-point temperature due to natural contamination was found to be below 0.1 mK. The largest rate of change of dew-point temperature was 26 µK/month. Thus, if proper cleanness is maintained in a humidity generator the effect of contamination of water in the saturator is insignificant compared with the major uncertainty components even in the most accurate generators today.

Biggs AAF, El Paso, Texas. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

DTIC Science & Technology

1981-01-14

wet-bulb temperature depression versus dry -bulb temperature, means and standard deviations of d-j-bulb, wet-bulb (over) SDD, 1473 UNCLASS IF I ED FC...distribution tables Dry -bulb temperature versud wet-bulb temperature Cumulative percentage frequency of distribution tables 20. and dew point...PART 5 PRECIPITATION PSYCHROMETRIC.DRY VS WET BULB SNOWFALL MEAN & STO 0EV SNOW EPTH DRY BULB, WET BULB, &DEW POINtI RELATIVE HUMIDITY PARTC SURFACE

Critical point analysis of phase envelope diagram

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soetikno, Darmadi; Siagian, Ucok W. R.; Kusdiantara, Rudy, E-mail: rkusdiantara@s.itb.ac.id

2014-03-24

Phase diagram or phase envelope is a relation between temperature and pressure that shows the condition of equilibria between the different phases of chemical compounds, mixture of compounds, and solutions. Phase diagram is an important issue in chemical thermodynamics and hydrocarbon reservoir. It is very useful for process simulation, hydrocarbon reactor design, and petroleum engineering studies. It is constructed from the bubble line, dew line, and critical point. Bubble line and dew line are composed of bubble points and dew points, respectively. Bubble point is the first point at which the gas is formed when a liquid is heated. Meanwhile,more » dew point is the first point where the liquid is formed when the gas is cooled. Critical point is the point where all of the properties of gases and liquids are equal, such as temperature, pressure, amount of substance, and others. Critical point is very useful in fuel processing and dissolution of certain chemicals. Here in this paper, we will show the critical point analytically. Then, it will be compared with numerical calculations of Peng-Robinson equation by using Newton-Raphson method. As case studies, several hydrocarbon mixtures are simulated using by Matlab.« less

Determination of dew point conditions for CO2 with impurities using microfluidics.

PubMed

Song, Wen; Fadaei, Hossein; Sinton, David

2014-03-18

Impurities can greatly modify the phase behavior of carbon dioxide (CO2), with significant implications on the safety and cost of transport in pipelines. In this paper we demonstrate a microfluidic approach to measure the dew point of such mixtures, specifically the point at which water in supercritical CO2 mixtures condenses to a liquid state. The method enables direct visualization of dew formation (∼ 1-2 μm diameter droplets) at industrially relevant concentrations, pressures, and temperatures. Dew point measurements for the well-studied case of pure CO2-water agreed well with previous theoretical and experimental data over the range of pressure (up to 13.17 MPa), temperature (up to 50 °C), and water content (down to 0.00229 mol fraction) studied. The microfluidic approach showed a nearly 3-fold reduction in error as compared to previous methods. When applied to a mixture with nitrogen (2.5%) and oxygen (5.8%) impurities--typical of flue gas from natural gas oxy-fuel combustion processes--the measured dew point pressure increased on average 17.55 ± 5.4%, indicating a more stringent minimum pressure for pipeline transport. In addition to increased precision, the microfluidic method offers a direct measurement of dew formation, requires very small volumes (∼ 10 μL), and is applicable to ultralow water contents (<0.005 mol fractions), circumventing the limits of previous methods.

BILATERAL KEY COMPARISON SIM.T-K6.1 ON HUMIDITY STANDARDS IN THE DEW/FROST-POINT TEMPERATURE RANGE FROM -25 °C TO +20 °C.

PubMed

Meyer, C W; Hill, K D

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the National Research Council (NRC, Canada) between December 2014 and April, 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and NRC and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and NRC.

BILATERAL KEY COMPARISON SIM.T-K6.1 ON HUMIDITY STANDARDS IN THE DEW/FROST-POINT TEMPERATURE RANGE FROM −25 °C TO +20 °C

PubMed Central

Meyer, C.W.; Hill, K.D.

2015-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the National Research Council (NRC, Canada) between December 2014 and April, 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and NRC and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and NRC. PMID:26663952

Effects of dew point on selective oxidation of TRIP steels containing Si, Mn, and B

NASA Astrophysics Data System (ADS)

Lee, Suk-Kyu; Kim, Jong-Sang; Choi, Jin-Won; Kang, Namhyun; Cho, Kyung-Mox

2011-04-01

The selective oxidation of Si, Mn, and B on TRIP steel surfaces is a widely known phenomenon that occurs during heat treatment. However, the relationship between oxide formation and the annealing factors is not completely understood. This study examines the effect of the annealing conditions (dew point and annealing temperature) on oxide formation. A low dew point of -40 °C leads to the formation of Si-based oxides on the surface. A high dew point of -20 °C changes the oxide type to Mn-based oxides because the formation of Si oxides on the surface is suppressed by internal oxidation. Mn-based oxides exhibit superior wettability due to aluminothermic reduction during galvanizing.

Extreme precipitation response to climate perturbations in an atmospheric mesoscale model

NASA Astrophysics Data System (ADS)

Attema, Jisk J.; Loriaux, Jessica M.; Lenderink, Geert

2014-01-01

Observations of extreme (sub-)hourly precipitation at mid-latitudes show a large dependency on the dew point temperature often close to 14% per degree—2 times the dependency of the specific humidity on dew point temperature which is given by the Clausius-Clapeyron (CC) relation. By simulating a selection of 11 cases over the Netherlands characterized by intense showers, we investigate this behavior in the non-hydrostatic weather prediction model Harmonie at a resolution of 2.5 km. These experiments are repeated using perturbations of the atmospheric profiles of temperature and humidity: (i) using an idealized approach with a 2° warmer (colder) atmosphere assuming constant relative humidity, and (ii) using changes in temperature and humidity derived from a long climate change simulation at 2° global warming. All perturbations have a difference in the local dew point temperature compared to the reference of approximately 2°. Differences are considerable between the cases, with dependencies ranging from almost zero to an increase of 18% per degree rise of the dew point temperature. On average however, we find an increase of extreme precipitation intensity of 11% per degree for the idealized perturbation, and 9% per degree for the climate change perturbation. For the most extreme events these dependencies appear to approach a rate of 11-14% per degree, in closer agreement with the observed relation.

Transport-induced shifts in condensate dew-point and composition in multicomponent systems with chemical reaction

NASA Technical Reports Server (NTRS)

Rosner, D. E.; Nagarajan, R.

1985-01-01

Partial heterogeneous condensation phenomena in multicomponent reacting systems are analyzed taking into consideration the chemical element transport phenomena. It is demonstrated that the dew-point surface temperature in chemically reactive systems is not a purely thermodynamic quantity, but is influenced by the multicomponent diffusion and Soret-mass diffusion phenomena. Several distinct dew-points are shown to exist in such systems and, as a result of transport constraints, the 'sharp' locus between two chemically distinct condensates is systematically moved to a difference mainstream composition.

Multi-channel fiber optic dew and humidity sensor

NASA Astrophysics Data System (ADS)

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%.

Vertical profiles of ozone, carbon monoxide, and dew-point temperature obtained during GTE/CITE 1, October-November 1983. [Chemical Instrumentation Test and Evaluation

NASA Technical Reports Server (NTRS)

Fishman, Jack; Gregory, Gerald L.; Sachse, Glen W.; Beck, Sherwin M.; Hill, Gerald F.

1987-01-01

A set of 14 pairs of vertical profiles of ozone and carbon monoxide, obtained with fast-response instrumentation, is presented. Most of these profiles, which were measured in the remote troposphere, also have supporting fast-response dew-point temperature profiles. The data suggest that the continental boundary layer is a source of tropospheric ozone, even in October and November, when photochemical activity should be rather small. In general, the small-scale vertical variability between CO and O3 is in phase. At low latitudes this relationship defines levels in the atmosphere where midlatitude air is being transported to lower latitudes, since lower dew-point temperatures accompany these higher CO and O3 concentrations. A set of profiles which is suggestive of interhemispheric transport is also presented. Independent meteorological analyses support these interpretations.

BILATERAL KEY COMPARISON SIM.T-K6.5 ON HUMIDITY STANDARDS IN THE DEW/FROST-POINT TEMPERATURE RANGE FROM -30 °C TO +20 °C.

PubMed

Meyer, C W; Solano, A

2016-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures over the range -30 °C TO +20 °C was carried out by the National Institute of Standards and Technology (NIST, USA) and the Laboratorio Costarricense de Metrología (LACOMET, Costa Rica), between February 2015 and August 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and LACOMET and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining the degree of equivalence between the dew/frost-point standards of NIST and LACOMET.

BILATERAL KEY COMPARISON SIM.T-K6.5 ON HUMIDITY STANDARDS IN THE DEW/FROST-POINT TEMPERATURE RANGE FROM −30 °C TO +20 °C

PubMed Central

Meyer, C.W.; Solano, A.

2016-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures over the range −30 °C TO +20 °C was carried out by the National Institute of Standards and Technology (NIST, USA) and the Laboratorio Costarricense de Metrología (LACOMET, Costa Rica), between February 2015 and August 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and LACOMET and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining the degree of equivalence between the dew/frost-point standards of NIST and LACOMET. PMID:28066029

[An automatic dew-point hygrometer making use of beta-ray backscattering (author's transl)].

PubMed

Matsumoto, S; Kobayashi, H

1981-04-01

A proportional control system was employed on this hygrometer. The hygrometer was used in a box in which the temperature and the humidity were constantly regulated. The range of measured dew-point was from -26 degrees C to 60 degrees C in the atmospheric temperature of 0 degree C to 60 degrees C, that was the relative humidity of 12% to 100%, and the accuracy of the measurement was +/- 1 degree C.

Atmospheric moisture's influence on fire behavior: surface moisture and plume dynamics.

Treesearch

Brian E. Potter; Joseph J. Charney; Lesley A. Fusina

2006-01-01

Nine measures of atmospheric surface moisture are tested for statistical relationships with fire size and number of fires using data from the Great Lakes region of the United States. The measures include relative humidity, water vapor mixing ratio, mixing ratio deficit, vapor pressure, vapor pressure deficit, dew point temperature, dew point depression, wet bulb...

A MEMS-based super fast dew point hygrometer—construction and medical applications

NASA Astrophysics Data System (ADS)

Jachowicz, Ryszard S.; Weremczuk, Jerzy; Paczesny, Daniel; Tarapata, Grzegorz

2009-12-01

The paper shows how MEMS (micro-electro-mechanical system) technology and a modified principle of fast temperature control (by heat injection instead of careful control of cooling) can considerably improve the dynamic parameters of dew point hygrometers. Some aspects of MEMS-type integrated sensor construction and technology, whole measurement system design, the control algorithm to run the system as well as empirical dynamic parameters from the tests are discussed too. The hygrometer can easily obtain five to six measurements per second with an uncertainty of less than 0.3 K. The meter range is between -10 °C and 40 °C dew point. In the second part of the paper (section 2), two different successful applications in medicine based on fast humidity measurements have been discussed. Some specific constructions of these super fast dew point hygrometers based on a MEMS sensor as well as limited empirical results from clinical tests have been reported too.

The New LMK Primary Standard for Dew-Point Sensor Calibration: Evaluation of the High-Range Saturator Efficiency

NASA Astrophysics Data System (ADS)

Hudoklin, Domen; Drnovšek, Janko

2008-10-01

In the field of hygrometry, a primary dew-point standard can be realized according to several proven principles, such as single-pressure (1-P), two-pressure (2-P), or divided flow. Different realizations have been introduced by various national laboratories, each resulting in a stand-alone complex generation system. Recent trends in generator design favor the single-pressure principle without recirculation because it promises theoretically lower uncertainty and because it avoids problems regarding the leak tightness of the recirculation. Instead of recirculation, the efficiency of saturation, the key factor, is increased by preconditioning the inlet gas entering the saturator. For preconditioning, a presaturator or purifier is used to bring the dew point of the inlet stream close to the saturator temperature. The purpose of the paper is to identify the minimum requirements for the preconditioning system and the main saturator to assure efficient saturation for the LMK generator. Moreover, the aim is also to find out if the preconditioning system can be avoided despite the rather simple construction of the main saturator. If this proves to be the case, the generator design can be simplified while maintaining an accurate value of the generated dew point. Experiments were carried out within the scope of improving our existing primary generator in the above-ambient dew-point range up to +70°C. These results show the generated dew point is within the measurement uncertainty for any dew-point value of the inlet gas. Thus, the preconditioning subsystem can be avoided, which leads to a simplified generator design.

A microwave resonance dew-point hygrometer

NASA Astrophysics Data System (ADS)

Underwood, R. J.; Cuccaro, R.; Bell, S.; Gavioso, R. M.; Madonna Ripa, D.; Stevens, M.; de Podesta, M.

2012-08-01

We report the first measurements of a quasi-spherical microwave resonator used as a dew-point hygrometer. In conventional dew-point hygrometers, the condensation of water from humid gas flowing over a mirror is detected optically, and the mirror surface is then temperature-controlled to yield a stable condensed layer. In our experiments we flowed moist air from a humidity generator through a quasi-spherical resonator and detected the onset of condensation by measuring the frequency ratio of selected microwave modes. We verified the basic operation of the device over the dew-point range 9.5-13.5 °C by comparison with calibrated chilled-mirror hygrometers. These tests indicate that the microwave method may allow a quantitative estimation of the volume and thickness of the water layer which is condensed on the inner surface of the resonator. The experiments reported here are preliminary due to the limited time available for the work, but show the potential of the method for detecting not only water but a variety of other liquid or solid condensates. The robust all-metal construction should make the device appropriate for use in industrial applications over a wide range of temperatures and pressures.

Final report on CCT-K6: Comparison of local realisations of dew-point temperature scales in the range -50 °C to +20 °C

NASA Astrophysics Data System (ADS)

Bell, S.; Stevens, M.; Abe, H.; Benyon, R.; Bosma, R.; Fernicola, V.; Heinonen, M.; Huang, P.; Kitano, H.; Li, Z.; Nielsen, J.; Ochi, N.; Podmurnaya, O. A.; Scace, G.; Smorgon, D.; Vicente, T.; Vinge, A. F.; Wang, L.; Yi, H.

2015-01-01

A key comparison in dew-point temperature was carried out among the national standards held by NPL (pilot), NMIJ, INTA, VSL, INRIM, MIKES, NIST, NIM, VNIIFTRI-ESB and NMC. A pair of condensation-principle dew-point hygrometers was circulated and used to compare the local realisations of dew point for participant humidity generators in the range -50 °C to +20 °C. The duration of the comparison was prolonged by numerous problems with the hygrometers, requiring some repairs, and several additional check measurements by the pilot. Despite the problems and the extended timescale, the comparison was effective in providing evidence of equivalence. Agreement with the key comparison reference value was achieved in the majority of cases, and bilateral degrees of equivalence are also reported. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Effect of the temperature and dew point of the decarburization process on the oxide subscale of a 3% silicon steel

NASA Astrophysics Data System (ADS)

Cesar, Maria das Graças M. M.; Mantel, Marc J.

2003-01-01

The oxide subscale formed on the decarburization annealing of 3% Si-Fe was investigated using microscopy and spectroscopy techniques. It was found that the morphology as well as the molecular structure of the subscale are affected by temperature and dew point. The results suggest that there is an optimum level of internal oxidation and an optimum fayalite/silica ratio in the subscale to achieve a oriented grain silicon steel having a continuous and smooth ceramic film and low core loss.

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

NASA Astrophysics Data System (ADS)

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.

The measurement of tiny dew droplets at the initial deposition stage and dew point using a phase-shift interference microscope

NASA Astrophysics Data System (ADS)

Shigeaki, Matsumoto

2003-12-01

The shape of a dew droplet deposited on the mirror surface of a copper plate was measured accurately using an interference microscope that employed a phase-shift technique. The microscope was constructed by adding a piezoelectric transducer to an interference microscope. A simple method that uses a conventional speaker horn and an optical fibre cable was used to depress any speckle noise. The shape of a dew droplet deposited at dew point on the plate surface with average roughness of 0.1 µm was measured with an accuracy of ± 3 nm. The mass of a tiny dew droplet could be determined from the volume of its shape and was of the order of 10-9 g. The total mass of a dew droplet deposited per unit area and the deposition velocity under a gentle wind were also obtained in a similar way. The total mass was of the order of 10-5 g cm-2 at the beginning of deposition and the deposition velocity ranged from 1 × 10-5 to 6 × 10-5 g cm-2 min-1 at room temperature.

FIRE_AX_SOF_ARAT_FLT

Atmospheric Science Data Center

2015-11-25

... Microwave Radiometer Optical Counter Platinum Resistance Pyranometer Pyrgeometer Variable Capacitance ... Parameters:  Aerosol Particle Properties Air Temperature Cloud Liquid Water Deiced Temperature Dew Point Doppler ...

Development of the High-Temperature Dew-Point Generator Over the Past 15 Years

NASA Astrophysics Data System (ADS)

Bosma, R.; Nielsen, J.; Peruzzi, A.

2017-10-01

At VSL a humidity generator was designed and constructed in the early 1990s. This generator was of the re-circulating-single-pressure type. Over the years, the generator has been thoroughly revised and several critical components have been replaced. Among others the pre-saturator and the change from re-circulation to single-pass mode. Validating experiments showed that the range of the new setup could be extended from 70 {°}C to 95 {°}C dew-point temperature, and the last modification allows an uncertainty of 0.048 {°}C (k = 2) at the maximum temperature. In 2009 the setup was used in the Euramet-T-K8 humidity intercomparison at temperatures up to 95 {°}C. In the period from 2003 to 2015, four state-of-the-art chilled mirror hygrometers were regularly calibrated with the generator. One of these was also calibrated with the primary dew-point standards of several other European National Metrology Institutes, which made it possible to link the VSL generator to the generators used in these institutes. An analysis of the results of these calibrations shows an agreement in calibration capabilities within 0.01 {°}C with PTB and NPL.

Intercomparison of the Dew-Point Temperature Realizations at LPM and MIKES in the Range from -70 °C to + 20 ° C

NASA Astrophysics Data System (ADS)

Heinonen, Martti; Zvizdic, Davor; Sestan, Danijel

2012-09-01

The first European humidity key comparison EURAMET-T.K6 was completed in 2008, and it covered the dew-point temperature range from -50 °C to + 20 °C. Both LPM and MIKES participated in the comparison, but a new low dew-point generator was introduced at LPM as a result of progress in the EUROMET P912 project. To extend the range of available comparison evidence down to -70 °C and to study the validity of improved uncertainties of LPM, a bilateral comparison was carried out between LPM and MIKES in 2009-2010. The applied comparison procedure was similar to that applied in EURAMET-T.K6. However, only one transfer standard was used instead of two units and the measurement point -70 °C was added in the measurement scheme. The results show that the bilateral equivalence between LPM and MIKES is between (0.00 ± 0.06) °C and (0.02 ± 0.08) °C in the range from -50 °C to + 20 °C and (0.01 ± 0.10) °C at -70 °C. Using MIKES results as the link to the EURAMET.T-K6, it is shown that the difference between the results obtained with the new LPM dew-point temperature standard and the EURAMET Comparison Reference Values is between (-0.02 ± 0.08) °C at 20 °C and (+ 0.02 ± 0.07) ° C at -50 °C.

FIRE_AX_UKMO_C130

Atmospheric Science Data Center

2015-11-25

... FSSP Gust Probe Hot-Wire Hygrometer Platinum Resistance PMS 2D-C Probe PRT-4 Pyranometer Pyrgeometer ... Parameters:  Barometric Altitude Cloud Top Temperature Deiced Temperature Dew/Frost Point Temperature Droplet ...

Smart textile plasmonic fiber dew sensors.

PubMed

Esmaeilzadeh, Hamid; Rivard, Maxime; Arzi, Ezatollah; Légaré, François; Hassani, Alireza

2015-06-01

We propose a novel Surface Plasmon Resonance (SPR)-based sensor that detects dew formation in optical fiber-based smart textiles. The proposed SPR sensor facilitates the observation of two phenomena: condensation of moisture and evaporation of water molecules in air. This sensor detects dew formation in less than 0.25 s, and determines dew point temperature with an accuracy of 4%. It can be used to monitor water layer depth changes during dew formation and evaporation in the range of a plasmon depth probe, i.e., 250 nm, with a resolution of 7 nm. Further, it facilitates estimation of the relative humidity of a medium over a dynamic range of 30% to 70% by measuring the evaporation time via the plasmon depth probe.

FIRE_MS_UKMO_C130

Atmospheric Science Data Center

2015-11-25

... Hot-Wire MCRW Refractometer Platinum Resistance Pressure Transducer RT-4 Pyranometer Pyrgeometer Radiometer Wind ... Parameters:  Dew/Frost Point Temperature Liquid Water Content Humidity Temperature Pressure Irradiance ...

Dew-point hygrometry system for measurement of evaporative water loss in infants.

PubMed

Ariagno, R L; Glotzbach, S F; Baldwin, R B; Rector, D M; Bowley, S M; Moffat, R J

1997-03-01

Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditions such as relative humidity, surface temperature, and convection currents. We have developed a ventilated capsule method that minimized these potential sources of measurement error and that allowed second-by-second, long-term, continuous measurements of evaporative water loss in sleeping infants. Air with a controlled reference humidity (dew-point temperature = 0 degree C) is delivered to a small, lightweight skin capsule and mixed with the vapor on the surface of the skin. The dew point of the resulting mixture is measured by using a chilled mirror dew-point hygrometer. The system indicates leaks, is mobile, and is accurate within 2%, as determined by gravimetric calibration. Examples from a recording of a 13-wk-old full-term infant obtained by using the system give evaporative water loss rates of approximately 0.02 mgH2O.cm-2.min-1 for normothermic baseline conditions and values up to 0.4 mgH2O.cm-2. min-1 when the subject was being warmed. The system is effective for clinical investigations that require dynamic measurements of water loss.

ASSESSMENT of POTENTIAL CARBON DIOXIDE-BASED DEMAND CONTROL VENTILATION SYSTEM PERFORMANCE in SINGLE ZONE SYSTEMS

DTIC Science & Technology

2013-03-21

and timers use a time-based estimate to predict how many people are in a facility at a given point in the day. CO2-based DCV systems measure CO2...energy and latent energy from the outside air when the coils’ surface temperature is below the dew point of the air passing over the coils (ASHRAE...model assumes that the dew point water saturation pressure is the same as the dry-bulb water vapor pressure, consistent with a typical ASHRAE

Investigation of the Equivalence of National Dew-Point Temperature Realizations in the -50 °C to + 20 °C Range

NASA Astrophysics Data System (ADS)

Heinonen, Martti; Anagnostou, Miltiadis; Bell, Stephanie; Stevens, Mark; Benyon, Robert; Bergerud, Reidun Anita; Bojkovski, Jovan; Bosma, Rien; Nielsen, Jan; Böse, Norbert; Cromwell, Plunkett; Kartal Dogan, Aliye; Aytekin, Seda; Uytun, Ali; Fernicola, Vito; Flakiewicz, Krzysztof; Blanquart, Bertrand; Hudoklin, Domen; Jacobson, Per; Kentved, Anders; Lóio, Isabel; Mamontov, George; Masarykova, Alexandra; Mitter, Helmut; Mnguni, Regina; Otych, Jan; Steiner, Anton; Szilágyi Zsófia, Nagyné; Zvizdic, Davor

2012-09-01

In the field of humidity quantities, the first CIPM key comparison, CCT-K6 is at its end. The corresponding European regional key comparison, EUROMET.T-K6, was completed in early 2008, about 4 years after the starting initial measurements in the project. In total, 24 NMIs from different countries took part in the comparison. This number includes 22 EURAMET countries, and Russia and South Africa. The comparison covered the dew-point temperature range from -50 °C to +20 °C. It was carried out in three parallel loops, each with two chilled mirror hygrometers as transfer standards in each loop. The comparison scheme was designed to ensure high quality results with evenly spread workload for the participants. It is shown that the standard uncertainty due to the long-term instability was smaller than 0.008 °C in all loops. The standard uncertainties due to links between the loops were found to be smaller than 0.025 °C at -50 °C and 0.010 °C elsewhere. Conclusions on the equivalence of the dew-point temperature standards are drawn on the basis of calculated bilateral degrees of equivalence and deviations from the EURAMET comparison reference values (ERV). Taking into account 16 different primary dew-point realizations and 8 secondary realizations, the results demonstrate the equivalence of a large number of laboratories at an uncertainty level that is better than achieved in other multilateral comparisons so far in the humidity field.

FIRE_CI2_CITATN_1HZ

Atmospheric Science Data Center

2015-11-25

... Flow Angle Sensors Hot-Wire Icing Rate Detector Pressure Transducer Reverse Flow Temperature Probes Spatial ... Condensation Nuclei Dew/Frost Point Temperature Liquid Water Content Nitrogen Dioxide Ozone Pressure Supercooled ...

Technical report: The design and evaluation of a basin-scale wireless sensor network for mountain hydrology

NASA Astrophysics Data System (ADS)

Zhang, Ziran; Glaser, Steven D.; Bales, Roger C.; Conklin, Martha; Rice, Robert; Marks, Danny G.

2017-05-01

A network of sensors for spatially representative water-balance measurements was developed and deployed across the 2000 km2 snow-dominated portion of the upper American River basin, primarily to measure changes in snowpack and soil-water storage, air temperature, and humidity. This wireless sensor network (WSN) consists of 14 sensor clusters, each with 10 measurement nodes that were strategically placed within a 1 km2 area, across different elevations, aspects, slopes, and canopy covers. Compared to existing operational sensor installations, the WSN reduces hydrologic uncertainty in at least three ways. First, redundant measurements improved estimation of lapse rates for air and dew-point temperature. Second, distributed measurements captured local variability and constrained uncertainty in air and dew-point temperature, snow accumulation, and derived hydrologic attributes important for modeling and prediction. Third, the distributed relative-humidity measurements offer a unique capability to monitor upper-basin patterns in dew-point temperature and characterize elevation gradient of water vapor-pressure deficit across steep, variable topography. Network statistics during the first year of operation demonstrated that the WSN was robust for cold, wet, and windy conditions in the basin. The electronic technology used in the WSN-reduced adverse effects, such as high current consumption, multipath signal fading, and clock drift, seen in previous remote WSNs.

Estimation of precipitable water at different locations using surface dew-point

NASA Astrophysics Data System (ADS)

Abdel Wahab, M.; Sharif, T. A.

1995-09-01

The Reitan (1963) regression equation of the form ln w = a + bT d has been examined and tested to estimate precipitable water vapor content from the surface dew point temperature at different locations. The results of this study indicate that the slope b of the above equation has a constant value of 0.0681, while the intercept a changes rapidly with latitude. The use of the variable intercept technique can improve the estimated result by about 2%.

Development of a Dew-Point Generator for Gases Other than Air and Nitrogen and Pressures up to 6 MPa

NASA Astrophysics Data System (ADS)

Bosma, R.; Peruzzi, A.

2012-09-01

A new primary humidity standard is currently being developed at VSL that, in addition to ordinary operation with air and nitrogen at atmospheric pressure, can be operated also with special carrier gases such as natural gas and SF6 and at pressures up to 6 MPa. In this paper, the design and construction of this new primary dew-point generator and the preliminary tests performed on the generator are reported. The results of the first efficiency tests, performed for the dew-point temperature range from -50 °C to 20°C, for pressures up to 0.7MPa and for carrier gas flow rates up to 4L· min-1, showed satisfactory generator performance when used in the single-pass mode, i.e., with no recirculation of the carrier gas.

Bilateral key comparison SIM.T-K6.5 on humidity standards in the dew/frost-point temperature range from -30 °C to +20 °C

NASA Astrophysics Data System (ADS)

Meyer, C.; Solano, A.

2016-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the Laboratorio Costarricense de Metrología (LACOMET, Costa Rica) between February 2015 and August 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and LACOMET and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and LACOMET. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Bilateral key comparison SIM.T-K6.2 on humidity standards in the dew/frost-point temperature range from -20 °c to 20 °c

NASA Astrophysics Data System (ADS)

Huang, P. H.; Meyer, C. W.; Martines-López, E.; Dávila Pacheco, J. A.; Méndez-Lango, E.

2014-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the Centro Nacional de Metrologia (CENAM, Mexico) between July 2008 and December 2008. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and CENAM and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and CENAM. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Final report: Bilateral key comparison SIM.T-K6.3 on humidity standards in the dew/frost-point temperature range from -30°C to 20°C

NASA Astrophysics Data System (ADS)

Huang, Peter; Meyer, Christopher; Brionizio, Julio D.

2015-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO, Brazil) between October 2009 and March 2010. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and INMETRO and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and INMETRO. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Simulating soybean canopy temperature as affected by weather variables and soil water potential

NASA Technical Reports Server (NTRS)

Choudhury, B. J.

1982-01-01

Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

Device of dispensing micro doses of aqueous solutions of substances onto a carrier and device for carrying out said method

DOEpatents

Ershow, Gennady Moiseevich; Kirillov, Evgenii Vladislavovich; Mirzabekov, Andrei Darievich

1998-01-01

A device for dispensing microdoses of aqueous solutions are provided, whereby the substance is transferred by the free surface end of a rodlike transferring element; the temperature of the transferring element is maintained at essentially the dew point of the ambient air during the transfer. The device may comprise a plate-like base to which are affixed a plurality of rods; the unfixed butt ends of the rods are coplanar. The device further comprises a means for maintaining the temperature of the unfixed butt ends of the rods essentially equal to the dew point of the ambient air during transfer of the aqueous substance.

FIRE_CI2_KINGAIR_IWC

Atmospheric Science Data Center

2015-11-25

... Dew/Frost Point Temperature Diffusional Growth Rate Ice Water Concent Particle Diameter Particle Number Concentration Precipitation Rate Radar Reflectivity Relative Humidity Static Pressure Vertical ...

FIRE_CI2_CITATN_IWC

Atmospheric Science Data Center

2015-11-25

... Dew/Frost Point Temperature Diffusional Growth Rate Ice Water Content Particle Diameter Particle Number Concentration Precipitation Rate Radar Reflectivity Relative Humidity Static Pressure Vertical ...

FIRE_CI2_SABRLNR_IWC

Atmospheric Science Data Center

2015-11-25

... Dew/Frost Point Temperature Diffusional Growth Rate Ice Water Content Particle Diameter Particle Number Concentration Preciptiation Rate Radar Reflectivity Relative Humidity Static Pressure Vertical ...

Simulating sunflower canopy temperatures to infer root-zone soil water potential

NASA Technical Reports Server (NTRS)

Choudhury, B. J.; Idso, S. B.

1983-01-01

A soil-plant-atmosphere model for sunflower (Helianthus annuus L.), together with clear sky weather data for several days, is used to study the relationship between canopy temperature and root-zone soil water potential. Considering the empirical dependence of stomatal resistance on insolation, air temperature and leaf water potential, a continuity equation for water flux in the soil-plant-atmosphere system is solved for the leaf water potential. The transpirational flux is calculated using Monteith's combination equation, while the canopy temperature is calculated from the energy balance equation. The simulation shows that, at high soil water potentials, canopy temperature is determined primarily by air and dew point temperatures. These results agree with an empirically derived linear regression equation relating canopy-air temperature differential to air vapor pressure deficit. The model predictions of leaf water potential are also in agreement with observations, indicating that measurements of canopy temperature together with a knowledge of air and dew point temperatures can provide a reliable estimate of the root-zone soil water potential.

Single Particle Studies of Heterogeneous Atmospheric Chemistry on Aluminum Oxide Particles in a Quadrupole Trap

DTIC Science & Technology

2000-03-01

For Figures 17 and 18, the H20 content of the N2 gas flow is ណ ppm ( dew point < 220 K); for Figure 19, the HC1 content of the gas stream is 30 ppm...the same temperature to prevent supersaturation. We have calibrated the water delivery system in H2S04 trapping experiments, 35 by a dew point ...We have investigated the activities of different types of aluminum oxide particles for uptake of gas -phase H20 and HCI. The particle types

Measuring Relative Humidity.

ERIC Educational Resources Information Center

Pinkham, Chester A.; Barrett, Kristin Burrows

1992-01-01

Describes four experiments that enable students to explore the phenomena of evaporation and condensation and determine the relative humidity by measuring air temperature and dew point on warm September days. Provides tables to calculate saturation points and relative humidity. (MDH)

A new construction of measurement system based on specialized microsystem design for laryngological application

NASA Astrophysics Data System (ADS)

Paczesny, Daniel; Mikłaszewicz, Franciszek

2013-10-01

This article describes the design, construction and parameters of diagnostic medical system for air humidity measurement which can be proceeded in various places of human nasal cavities and also human throat. The system can measure dynamic changes of dew point temperature (absolute value of humidity) of inspired and expired air in different places of human upper airways. During regular respiration process dew point temperature is measured in nasal cavity, middle part cavity and nasopharynx. The presented system is the next step in construction of measurement system based on specialized microsystem for laryngological application. The microsystem fabricated on silicon substrate includes microheater, microthermoresistor and interdigitated electrodes. In comparison with previously built measurement system with current version some system functionalities and measurement parameters were improved. Additionally 3D printing technology was applied for rapid prototyping a measurement system housing. Presented measurement system is set of microprocessor module with signal conditioning circuits; heated measurement head based on specialized microsystem with disposable heated pipe for air sucking from various places of upper airways; power supplier and computer application for monitoring all system parameters and presenting on-line and off-line measured results. Some example results of constructed measurement system and dew point temperature measurements during respiration cycle are presented.

Association between weather conditions and the number of patients at the emergency room in an Argentine hospital

NASA Astrophysics Data System (ADS)

Rusticucci, Matilde; Bettolli, Laura M.; de los Angeles Harris, M.

2002-02-01

The aim of this paper is to study the relationships between hospital emergencies and weather conditions by analysing summer and winter cases of patients requiring attention at the emergency room of a hospital in the city of Buenos Aires, Argentina. Hospital data have been sorted into seven different diagnostic groups as follows: (1) respiratory, cardiovascular and chest-pain complaints; (2) digestive, genitourinary and abdominal complaints; (3) neurological and psychopathological disorders; (4) infections; (5) contusion and crushing, bone and muscle complaints; (6) skin and allergies and (7) miscellaneous complaints. In general, there is an increase of 16.7% in winter while, for group 2 and group 6, there are more patients in summer, 54% and 75% respectively. In summer, the total number of patients for group 6 shows a significant positive correlation with temperature and dew-point temperature, and a negative correlation with the sea-level pressure for the same day. In winter, the same relationship exists, however its correlation is not as strong. The lags observed between these three variables: maximum dew-point temperature, maximum temperature, minimum air pressure and the peaks in admissions are 1, 2 and 4 days respectively. In winter, increases in temperature and dew point and decreases in pressure are followed by a peak in admissions for group 2. In winter, there are significantly more cases in group 5 on warm, dry days and on warm, wet days in the summer.

FIRE_ACE_UWCV580_UWA

Atmospheric Science Data Center

2017-04-26

... of Washington CV-580 Instrument:  Platinum resistance Chilled mirror Particle Measuring Systems Electron ... Search Parameters:  Pressure Temperature Dew point Humidity Turbulence Liquid water content ...

Monthly variations of dew point temperature in the coterminous United States

NASA Astrophysics Data System (ADS)

Robinson, Peter J.

1998-11-01

The dew point temperature, Td, data from the surface airways data set of the U.S. National Climatic Data Center were used to develop a basic dew point climatology for the coterminous United States. Quality control procedures were an integral part of the analysis. Daily Td, derived as the average of eight observations at 3-hourly intervals, for 222 stations for the 1961-1990 period were used. The annual and seasonal pattern of average values showed a clear south-north decrease in the eastern portion of the nation, a trend which was most marked in winter. In the west, values decreased inland from the Pacific Coast. Inter-annual variability was generally low when actual mean values were high. A cluster analysis suggested that the area could be divided into six regions, two oriented north-south in the west, four aligned east-west in the area east of the Rocky Mountains. Day-to-day variability was low in all seasons in the two western clusters, but showed a distinct winter maximum in the east. This was explained in broad terms by consideration of air flow regimes, with the Pacific Ocean and the Gulf of Mexico acting as the major moisture sources. Comparison of values for pairs of nearby stations suggested that Td was rather insensitive to local moisture sources. Analysis of the patterns of occurrence of dew points exceeding the 95th percentile threshold indicated that extremes in summer tend to be localized and short-lived, while in winter they are more widespread and persistent.

Temporal trends in United States dew point temperatures

NASA Astrophysics Data System (ADS)

Robinson, Peter J.

2000-07-01

In this study, hourly data for the 1951-1990 period for 178 stations in the coterminous United States were used to establish temporal trends in dew point temperature. Although the data had been quality controlled previously (Robinson, 1998. Monthly variations of dew point temperatures in the coterminous United States. International Journal of Climatology 18: 1539-1556), comparisons of values between nearby stations suggested that instrumental changes, combined with locational changes, may have modified the results by as much as 1°C during the 40-year period. Nevertheless, seasonally averaged results indicated an increase over much of the area, of slightly over 1°C/100 years in spring and autumn, slightly less than this in summer. Winter displayed a drying of over 1°C/100 years. When only the 1961-1990 period was considered, the patterns were similar and trends increased by approximately 1-2°C/100 years, except in autumn, which displayed a slight drying. Analyses for specific stations indicated periods of both increasing and decreasing Td, the change between them varying with observation hour. No single change point was common over a wide area, although January commonly indicated maximum values early in the period in the east and west, and much later in the north-central portion. Rates of increase were generally higher in daytime than at night, especially in summer. Investigation of the inter-decadal differences in dew point, as a function of wind conditions, indicated that changes during calm conditions were commonly similar in magnitude to that of the overall average changes, suggesting an important role for the local hydrologic cycle in driving changes. Other inter-decadal changes could be attributed to the changes in the frequency and moisture content of invading air-streams. This was particularly clear for the changes in north-south flow in the interior.

Theoretical and testing performance of an innovative indirect evaporative chiller

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Yi; Xie, Xiaoyun

2010-12-15

An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirectmore » evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller successfully satisfy the indoor air conditioning load for the demo building. The indirect evaporative chiller has a potentially wide application in dry regions, especially for large scale commercial buildings. Finally, this paper presented the geographic regions suitable for the technology worldwide. (author)« less

Bilateral key comparison SIM.T-K6.1 on humidity standards in the dew/frost-point temperature range from -25 °C to +20 °C

NASA Astrophysics Data System (ADS)

Meyer, C. W.; Hill, K. D.

2015-01-01

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures was carried out by the National Institute of Standards and Technology (NIST, USA) and the National Research Council (NRC, Canada) between December 2014 and April 2015. The results of this comparison are reported here, along with descriptions of the humidity laboratory standards for NIST and NRC and the uncertainty budget for these standards. This report also describes the protocol for the comparison and presents the data acquired. The results are analyzed, determining degree of equivalence between the dew/frost-point standards of NIST and NRC. This paper is the final report of the comparison including analysis of the uncertainty of measurement results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT WG-KC, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Method Of Dispensing Microdoses Of A Aqueous Solutions Of S Ubstances Onto A Carrier And A Device For Carrying Out Said Method

DOEpatents

Ershov, Gennady Moiseevich; Kirillov, Eugenii Vladislavovich; Mirzabekov, Andrei Darievich

1999-10-05

A method and a device for dispensing microdoses of aqueous solutions are provided, whereby the substance is transferred by the free surface end of a rodlike transferring element; the temperature of the transferring element is maintained at essentially the dew point of the ambient air during the transfer. The device may comprise a plate-like base to which are affixed a plurality of rods; the unfixed butt ends of the rods are coplanar. The device further comprises a means for maintaining the temperature of the unfixed butt ends of the rods essentially equal to the dew point of the ambient air during transfer of the aqueous substance

FIRE_AX_UW_C131A

Atmospheric Science Data Center

2015-11-25

... Hot-Wire Hygrometer RMS Pressure Var Platinum Resistance Pyranometer Radiometer Reverse Flow Spatial ... Parameters:  Condensation Nuclei Dew/Frost Point Temperature Droplet Concentration Humidity Irradiance Liquid Water ...

Mapping Atmospheric Moisture Climatologies across the Conterminous United States

PubMed Central

Daly, Christopher; Smith, Joseph I.; Olson, Keith V.

2015-01-01

Spatial climate datasets of 1981–2010 long-term mean monthly average dew point and minimum and maximum vapor pressure deficit were developed for the conterminous United States at 30-arcsec (~800m) resolution. Interpolation of long-term averages (twelve monthly values per variable) was performed using PRISM (Parameter-elevation Relationships on Independent Slopes Model). Surface stations available for analysis numbered only 4,000 for dew point and 3,500 for vapor pressure deficit, compared to 16,000 for previously-developed grids of 1981–2010 long-term mean monthly minimum and maximum temperature. Therefore, a form of Climatologically-Aided Interpolation (CAI) was used, in which the 1981–2010 temperature grids were used as predictor grids. For each grid cell, PRISM calculated a local regression function between the interpolated climate variable and the predictor grid. Nearby stations entering the regression were assigned weights based on the physiographic similarity of the station to the grid cell that included the effects of distance, elevation, coastal proximity, vertical atmospheric layer, and topographic position. Interpolation uncertainties were estimated using cross-validation exercises. Given that CAI interpolation was used, a new method was developed to allow uncertainties in predictor grids to be accounted for in estimating the total interpolation error. Local land use/land cover properties had noticeable effects on the spatial patterns of atmospheric moisture content and deficit. An example of this was relatively high dew points and low vapor pressure deficits at stations located in or near irrigated fields. The new grids, in combination with existing temperature grids, enable the user to derive a full suite of atmospheric moisture variables, such as minimum and maximum relative humidity, vapor pressure, and dew point depression, with accompanying assumptions. All of these grids are available online at http://prism.oregonstate.edu, and include 800-m and 4-km resolution data, images, metadata, pedigree information, and station inventory files. PMID:26485026

Investigation of Primary Dew-Point Saturator Efficiency in Two Different Thermal Environments

NASA Astrophysics Data System (ADS)

Zvizdic, D.; Heinonen, M.; Sestan, D.

2015-08-01

The aim of this paper is to describe the evaluation process of the performance of the low-range saturator (LRS), when exposed to two different thermal environments. The examined saturator was designed, built, and tested at MIKES (Centre for Metrology and Accreditation, Finland), and then transported to the Laboratory for Process Measurement (LPM) in Croatia, where it was implemented in a new dew-point calibration system. The saturator works on a single-pressure-single-pass generation principle in the dew/frost-point temperature range between and . The purpose of the various tests performed at MIKES was to examine the efficiency and non-ideality of the saturator. As a test bath facility in Croatia differs from the one used in Finland, the same tests were repeated at LPM, and the effects of different thermal conditions on saturator performance were examined. Thermometers, pressure gauges, an air preparation system, and water for filling the saturator at LPM were also different than those used at MIKES. Results obtained by both laboratories indicate that the efficiency of the examined saturator was not affected either by the thermal conditions under which it was tested or by equipment used for the tests. Both laboratories concluded that LRS is efficient enough for a primary realization of the dew/frost-point temperature scale in the range from to , with flow rates between and . It is also shown that a considerable difference of the pre-saturator efficiency, indicated by two laboratories, did not have influence to the overall performance of the saturator. The results of the research are presented in graphical and tabular forms. This paper also gives a brief description of the design and operation principle of the investigated low-range saturator.

Consistency of the National Realization of Dew-Point Temperature Using Standard Humidity Generators

NASA Astrophysics Data System (ADS)

Benyon, R.; Vicente, T.

2012-09-01

The comparison of two high-range standard humidity generators used by Instituto Nacional de Técnica Aeroespacial to realize dew-point temperature in the range from -10 °C to +95 °C has been performed using state-of-the art transfer standards and measurement procedures, over their overlapping range from -10 °C to +75 °C. The aim of this study is to investigate the level of agreement between the two generators, to determine any bias, and to quantify the level of consistency of the two realizations. The measurement procedures adopted to minimize the effect of the influence factors due to the transfer standards are described, and the results are discussed in the context of the declared calibration and measurement capabilities (CMCs).

Measuring Humidity in Sealed Glass Encasements

NASA Technical Reports Server (NTRS)

West, James W.; Burkett, Cecil G.; Levine, Joel S.

2005-01-01

A technique has been devised for measuring the relative humidity levels in the protective helium/water vapor atmosphere in which the Declaration of Independence, the United States Constitution, and the Bill of Rights are encased behind glass panels on display at the National Archives in Washington, DC. The technique is noninvasive: it does not involve penetrating the encasements (thereby risking contamination or damage to the priceless documents) to acquire samples of the atmosphere. The technique could also be applied to similar glass encasements used to protect and display important documents and other precious objects in museums. The basic principle of the technique is straightforward: An encasement is maintained at its normal display or operating temperature (e.g., room temperature) while a portion of its glass front panel is chilled (see Figure 1) until condensed water droplets become visible on the inside of the panel. The relative humidity of the enclosed atmosphere can then be determined as a known function of the dew point, the temperature below which the droplets condense. Notwithstanding the straightforwardness of the basic principle, careful attention to detail is necessary to enable accurate determination of the dew point. In the initial application, the affected portion of the glass panel was cooled by contact with an aluminum plate that was cooled by a thermoelectric module, the exhaust heat of which was dissipated by a heat sink cooled by a fan. A thermocouple was used to measure the interior temperature of the aluminum plate, and six other thermocouples were used to measure the temperatures at six locations on the cooled outer surface of the glass panel (see Figure 2). Thermal grease was applied to the aluminum plate and the thermocouples to ensure close thermal contact. Power was supplied to the thermoelectric module in small increments, based on previous laboratory tests. A small flashlight and a magnifying glass were used to look for water droplets condensing on the inner surface of the glass. The temperature readings of the thermocouples were taken during cool-down and upon observing condensation. In determining the dew point, it was necessary to make a correction for the differences between the temperatures measured on the chilled outer surface of the glass and the temperature of the inner surface, where the condensation took place. The correction was derived from a laboratory test on a measurement setup that was nearly identical, except that the dew location on the inner surface was also instrumented with a thermocouple. The test showed that the temperature at the dew location on the inner surface of the glass panel was 0.9 C above the temperature determined from the measurements on the chilled outer surface of the panel.

The thermodynamic and dynamical features of double front structures during 21 31 July 1998 in China

NASA Astrophysics Data System (ADS)

Zhou, Yushu; Deng, Guo; Lei, Ting; Ju, Jianhua

2005-11-01

The daily 1° × 1° data of the Aviation (AVN) model, the black body temperature (TBB) data of cloud top, and cloud images by geostationary meteorological satellite (GMS) are used to identify a dew-point front near the periphery of the western Pacific subtropical high (WPSH). The results clearly demonstrate the existence of the dew-point front, and its thermodynamic and dynamic structural characteristics are analyzed in detail. The dew-point front is a transitional belt between the moist southwest monsoon flow and the dry adiabatic sinking flow near the WPSH, manifested by a large horizontal moisture gradient in the mid-lower troposphere and conjugated with the mei-yu front to form a predominant double-front structure associated with intense rainfall in the mei-yu period. The mei-yu front is located between 30° and 35°N, vertically extends from the ground level to the upper level and shifts northward. The dew-point front is to the south of the mei-yu front and lies up against the periphery of the WPSH. Generally, it is located between 850 hPa and 500 hPa. On the dew-point front side, the southwesterly prevails at the lower level and the northeasterly at the upper level; this wind distribution is different from that on the mei-yu front side. Vertical ascending motion exists between the two fronts, and there are descending motions on the north side of the mei-yu front and on the south side of the dew-point front, which form a secondary circulation. The dynamics of the double fronts also have some interesting features. At the lower level, positive vertical vorticity and obvious convergence between the two fronts are clearly identified. At the mid-lower level, negative local change of the divergence (corresponding to increasing convergence) is often embedded in the two fronts or against the mei-yu front. Most cloud clusters occur between the two fronts and propagate down stream in a wave-like manner.

Selection for the best ETS (error, trend, seasonal) model to forecast weather in the Aceh Besar District

NASA Astrophysics Data System (ADS)

Amora Jofipasi, Chesilia; Miftahuddin; Hizir

2018-05-01

Weather is a phenomenon that occurs in certain areas that indicate a change in natural activity. Weather can be predicted using data in previous periods over a period. The purpose of this study is to get the best ETS model to predict the weather in Aceh Besar. The ETS model is a time series univariate forecasting method; its use focuses on trend and seasonal components. The data used are air temperature, dew point, sea level pressure, station pressure, visibility, wind speed, and sea surface temperature from January 2006 to December 2016. Based on AIC, AICc and BIC the smallest values obtained the conclusion that the ETS (M, N, A) is used to predict air temperature, and sea surface temperature, ETS (A, N, A) is used to predict dew point, sea level pressure and station pressure, ETS (A, A, N) is used to predict visibility, and ETS (A, N, N) is used to predict wind speed.

40 CFR 91.313 - Analyzers required.

Code of Federal Regulations, 2012 CFR

2012-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 90.313 - Analyzers required.

Code of Federal Regulations, 2013 CFR

2013-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 90.313 - Analyzers required.

Code of Federal Regulations, 2011 CFR

2011-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 91.313 - Analyzers required.

Code of Federal Regulations, 2014 CFR

2014-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 91.313 - Analyzers required.

Code of Federal Regulations, 2013 CFR

2013-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 91.313 - Analyzers required.

Code of Federal Regulations, 2011 CFR

2011-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 90.313 - Analyzers required.

Code of Federal Regulations, 2014 CFR

2014-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

40 CFR 90.313 - Analyzers required.

Code of Federal Regulations, 2012 CFR

2012-07-01

... condensation is acceptable. If water is removed by condensation, the sample gas temperature or sample dew point.... A water trap performing this function is an acceptable method. Means other than condensation may be...

Accumulation of ammonia and other potentially noxious gases on live export shipments from Australia to the Middle East.

PubMed

Pines, M K; Phillips, C J C

2011-10-01

Noxious gases on ships are irritant pollutants that have potential impacts on the comfort and health of both livestock and humans. Identification of environmental influences on the pollutants will assist live exporters to control them. Ammonia, hydrogen sulphide and carbon dioxide, as well as wet and dry bulb temperature, dew point, air speed and depth of faeces that the sheep stood in, were measured on two ship voyages in which sheep were transported from Australia to the Middle East. Daily measurements were made at 20 measurement locations over 12 days. At four sites, the mean ammonia concentration for the voyage was above the recommended maximum limit for the live export industry (25 ppm). The mean ammonia concentrations at the remaining 16 sites were below 18 ppm and considered safe. High ammonia concentrations were localised and occurred particularly on closed decks, as well as at the front of the vessel and near the engine block on open decks. Ammonia concentration on the open decks was correlated with cumulative wind during the voyage, air speed, dew point, wet bulb temperature and faecal pad depth, and on the closed decks with dew point, and wet and dry bulb temperature. Hydrogen sulphide (<1.8 ppm) and carbon dioxide (<1900 ppm) concentrations were low and did not pose a risk to animal or human welfare or health. The results suggest that high ammonia concentrations occur in those parts of the ship where there is insufficient ventilation and/or high temperatures and humidity.

Measurement Uncertainty of Dew-Point Temperature in a Two-Pressure Humidity Generator

NASA Astrophysics Data System (ADS)

Martins, L. Lages; Ribeiro, A. Silva; Alves e Sousa, J.; Forbes, Alistair B.

2012-09-01

This article describes the measurement uncertainty evaluation of the dew-point temperature when using a two-pressure humidity generator as a reference standard. The estimation of the dew-point temperature involves the solution of a non-linear equation for which iterative solution techniques, such as the Newton-Raphson method, are required. Previous studies have already been carried out using the GUM method and the Monte Carlo method but have not discussed the impact of the approximate numerical method used to provide the temperature estimation. One of the aims of this article is to take this approximation into account. Following the guidelines presented in the GUM Supplement 1, two alternative approaches can be developed: the forward measurement uncertainty propagation by the Monte Carlo method when using the Newton-Raphson numerical procedure; and the inverse measurement uncertainty propagation by Bayesian inference, based on prior available information regarding the usual dispersion of values obtained by the calibration process. The measurement uncertainties obtained using these two methods can be compared with previous results. Other relevant issues concerning this research are the broad application to measurements that require hygrometric conditions obtained from two-pressure humidity generators and, also, the ability to provide a solution that can be applied to similar iterative models. The research also studied the factors influencing both the use of the Monte Carlo method (such as the seed value and the convergence parameter) and the inverse uncertainty propagation using Bayesian inference (such as the pre-assigned tolerance, prior estimate, and standard deviation) in terms of their accuracy and adequacy.

Air Modeling - Observational Meteorological Data

EPA Pesticide Factsheets

Observed meteorological data for use in air quality modeling consist of physical parameters that are measured directly by instrumentation, and include temperature, dew point, wind direction, wind speed, cloud cover, cloud layer(s), ceiling height,

KEY COMPARISON Report to the CCT on key comparison EUROMET.T-K6 (EUROMET Project no. 621): Comparison of the realizations of local dew/frost-point temperature scales in the range -50 °C to +20 °C

NASA Astrophysics Data System (ADS)

Heinonen, Martti

2010-01-01

The first humidity CIPM key comparison, CCT-K6, will be completed in 2010. The corresponding European regional key comparison, EUROMET.T-K6, was carried out in 2004 to 2008. National metrology institutes from 24 countries participated in the comparison. The comparison covered the dew-point temperature range from -50 °C to +20 °C. It was organized as three parallel loops with two specially manufactured precision chilled mirror hygrometers as transfer standards in each loop. The comparison scheme was designed to ensure high quality results with evenly spread workload for the participants. MIKES was coordinating the project. This report presents the results of the comparison and provides detailed information on the measurements performed by all participating laboratories and the analysis of the results. Conclusions on the equivalence of the dew-point temperature standards are drawn on the basis of calculated bilateral degrees of equivalence and deviations from EURAMET comparison reference values (ERV). Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

New methods of subcooled water recognition in dew point hygrometers

NASA Astrophysics Data System (ADS)

Weremczuk, Jerzy; Jachowicz, Ryszard

2001-08-01

Two new methods of sub-cooled water recognition in dew point hygrometers are presented in this paper. The first one- impedance method use a new semiconductor mirror in which the dew point detector, the thermometer and the heaters were integrated all together. The second one an optical method based on a multi-section optical detector is discussed in the report. Experimental results of both methods are shown. New types of dew pont hydrometers of ability to recognized sub-cooled water were proposed.

EDITORIAL: Humidity sensors Humidity sensors

NASA Astrophysics Data System (ADS)

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 produced at relatively low cost. Therefore, they find wide use in lots of applications. However, the method requires a material that possesses some conflicting properties: stable and reproducible relations between air humidity, moisture uptake and a specific property (for instance the length of a hair, the electrical impedance of the material), fast absorption and desorption of the water vapour (to obtain a short response time), small hysteresis, wide range of relative humidity (RH) and temperature-independent output (only responsive to RH). For these reasons, much research is done and is still going on to find suitable materials that combine high performance and low price. In this special feature, three of the four papers report on absorption sensors, all with different focus. Aziz et al describe experiments with newly developed materials. The surface structure is extensively studied, in view of its ability to rapidly absorb water vapour and exhibit a reproducible change in the resistance and capacitance of the device. Sanchez et al employ optical fibres coated with a thin moisture-absorbing layer as a sensitive humidity sensor. They have studied various coating materials and investigated the possibility of using changes in optical properties of the fibre (here the lossy mode resonance) due to a change in humidity of the surrounding air. The third paper, by Weremczuk et al, focuses on a cheap fabrication method for absorption-based humidity sensors. The inkjet technology appears to be suitable for mass fabrication of such sensors, which is demonstrated by extensive measurements of the electrical properties (resistance and capacitance) of the absorbing layers. Moreover, they have developed a model that describes the relation between humidity and the electrical parameters of the moisture-sensitive layer. Despite intensive research, absorption sensors still do not meet the requirements for high accuracy applications. The dew-point temperature method is more appropriate, since it uses the accurately known relation between temperature and saturation vapour pressure in air. When an object exposed to humid air is cooled down below the dew-point water vapour condenses as drops on its cold surface. The temperature can be kept exactly at the dew point by controlling the amount of dew (equilibrium between evaporation and condensation). In most dew-point hygrometers dew is detected with optical or capacitive means. In the former the dew drops on a reflective surface (chilled mirror) scatter incident light, and the capacitive method uses the change in capacitance due to the large dielectric constant of liquid water (80) compared to air (1). Kunze et al, in the fourth paper of this special feature, use another property of water to detect dew: the relatively high value of the thermal capacitance of liquid water. In traditional technology this method would not be sensitive enough, but with MEMS technology a sufficient detectivity of dew can be achieved, which is demonstrated in this paper. A control system keeps the temperature of the substrate just at the dew-point temperature, the latter being measured by an on-chip diode. The accuracy achieved is comparable with traditional dew-point hygrometers. These four papers in this issue are nice examples of research leading to significant advances in hygrometry. References [1] Wexler A (ed) 1965 Humidity and Moisture. Vol. I: Principles and Methods of Measuring Humidity in Gases; Vol. II: Applications; Vol. III: Fundamentals and Standards; Vol. IV: Principles and Methods of Measuring Moisture in Liquids and Solids (New York: Reinhold) [2] Sonntag D 1966-1968 Hygrometrie (Berlin: Akademie Verlag)

Use of dew-point hygrometry, direct sweat collection, and measurement of body water losses to determine sweating rates in exercising horses.

PubMed

Kingston, J K; Geor, R J; McCutcheon, L J

1997-02-01

To compare dew-point hygrometry, direct sweat collection, and measurement of body water loss as methods for determination of sweating rate (SR) in exercising horses. 6 exercise-trained Thoroughbreds. SR was measured in 6 horses exercising at 40% of the speed that elicited maximum oxygen consumption for 45 km, with a 15-minute rest at the end of each 15-km phase. Each horse completed 2 exercise trials. Dew-point hygrometry, as a method of local SR determination, was validated in vitro by measurement of rate of evaporative water loss. During exercise, local SR was determined every 10 minutes by the following 2 methods: (1) dew-point hygrometry on the neck and lateral area of the thorax, and (2) on the basis of the volume of sweat collected from a sealed plastic pouch attached to the lateral area of the thorax. Mean whole body SR was calculated from total body water loss incurred during exercise. Evaporation rate measured by use of dew-point hygrometry was significantly correlated (r2 = 0.92) with the actual rate of evaporative water loss. There was a similar pattern of change in SR measured by dew-point hygrometry on the neck and lateral area of the thorax during exercise, with a significantly higher SR on the neck. The SR measured on the thorax by direct sweat collection and by dew-point hygrometry were of similar magnitude. Mean whole body SR calculated from total body water loss was not significantly different from mean whole body SR estimated from direct sweat collection or dew-point hygrometry measurements on the thorax. Dew-point hygrometry and direct sweat collection are useful methods for determination of local SR in horses during prolonged, steady-state exercise in moderate ambient conditions. Both methods of local SR determination provide an accurate estimated of whole body SR.

Use of Cometabolic Air Sparging to Remediate Chloroethene-Contaminated Groundwater Aquifers

DTIC Science & Technology

2001-07-31

sampling event, the temperature, dew point , and relative humidity of the soil gas were analyzed using a Control Company Digital Hygrometer/Thermometer...4.2.1.3 Groundwater and Soil- Gas Multi-Level Monitoring Points .................... 20 4.2.1.4 Groundwater Monitoring Wells...C-1 APPENDIX D: SOIL- GAS MONITORING POINT DATA........................................................D-1 APPENDIX E: HISTORICAL

40 CFR 90.327 - Sampling system requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... each component (pump, sample line section, filters, and so forth) in the heated portion of the sampling... largest thermal mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may...

40 CFR 90.327 - Sampling system requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... each component (pump, sample line section, filters, and so forth) in the heated portion of the sampling... largest thermal mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may...

40 CFR 90.327 - Sampling system requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... each component (pump, sample line section, filters, and so forth) in the heated portion of the sampling... largest thermal mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may...

Parametric analysis of parameters for electrical-load forecasting using artificial neural networks

NASA Astrophysics Data System (ADS)

Gerber, William J.; Gonzalez, Avelino J.; Georgiopoulos, Michael

1997-04-01

Accurate total system electrical load forecasting is a necessary part of resource management for power generation companies. The better the hourly load forecast, the more closely the power generation assets of the company can be configured to minimize the cost. Automating this process is a profitable goal and neural networks should provide an excellent means of doing the automation. However, prior to developing such a system, the optimal set of input parameters must be determined. The approach of this research was to determine what those inputs should be through a parametric study of potentially good inputs. Input parameters tested were ambient temperature, total electrical load, the day of the week, humidity, dew point temperature, daylight savings time, length of daylight, season, forecast light index and forecast wind velocity. For testing, a limited number of temperatures and total electrical loads were used as a basic reference input parameter set. Most parameters showed some forecasting improvement when added individually to the basic parameter set. Significantly, major improvements were exhibited with the day of the week, dew point temperatures, additional temperatures and loads, forecast light index and forecast wind velocity.

Project Fog Drops. Part 1: Investigations of warm fog properties

NASA Technical Reports Server (NTRS)

Pilie, R. J.; Eadie, W.; Mack, E. J.; Rogers, C.; Kocmond, W. C.

1972-01-01

A detailed study was made of the micrometeorological and microphysical characteristics of eleven valley fogs occurring near Elmira, New York. Observations were made of temperature, dew point, wind speed and direction, dew deposition, vertical wind velocity, and net radiative flux. In fog, visibility was continuously recorded and periodic measurements were made of liquid water content and drop-size distribution. The observations were initiated in late evening and continued until the time of fog dissipation. The vertical distribution of temperature in the lowest 300 meters and cloud nucleus concentration at several heights were measured from an aircraft before fog nucleus concentrations at several heights were measured from an aircraft before fog formation. A numerical model was developed to investigate the life cycle of radiation fogs. The model predicts the temporal evolution of the vertical distributions of temperature, water vapor, and liquid water as determined by the turbulent transfer of heat and moisture. The model includes the nocturnal cooling of the earth's surface, dew formation, fog drop sedimentation, and the absorption of infrared radiation by fog.

Data set: 31 years of spatially distributed air temperature, humidity, precipitation amount and precipitation phase from a mountain catchment in the rain-snow transition zone

USDA-ARS?s Scientific Manuscript database

Thirty one years of spatially distributed air temperature, relative humidity, dew point temperature, precipitation amount, and precipitation phase data are presented for the Reynolds Creek Experimental Watershed. The data are spatially distributed over a 10m Lidar-derived digital elevation model at ...

Memory persistency and nonlinearity in daily mean dew point across India

NASA Astrophysics Data System (ADS)

Ray, Rajdeep; Khondekar, Mofazzal Hossain; Ghosh, Koushik; Bhattacharjee, Anup Kumar

2016-04-01

Enterprising endeavour has been taken in this work to realize and estimate the persistence in memory of the daily mean dew point time series obtained from seven different weather stations viz. Kolkata, Chennai (Madras), New Delhi, Mumbai (Bombay), Bhopal, Agartala and Ahmedabad representing different geographical zones in India. Hurst exponent values reveal an anti-persistent behaviour of these dew point series. To affirm the Hurst exponent values, five different scaling methods have been used and the corresponding results are compared to synthesize a finer and reliable conclusion out of it. The present analysis also bespeaks that the variation in daily mean dew point is governed by a non-stationary process with stationary increments. The delay vector variance (DVV) method has been exploited to investigate nonlinearity, and the present calculation confirms the presence of deterministic nonlinear profile in the daily mean dew point time series of the seven stations.

Trends in extremes of temperature, dew point, and precipitation from long instrumental series from central Europe

NASA Astrophysics Data System (ADS)

Kürbis, K.; Mudelsee, M.; Tetzlaff, G.; Brázdil, R.

2009-09-01

For the analysis of trends in weather extremes, we introduce a diagnostic index variable, the exceedance product, which combines intensity and frequency of extremes. We separate trends in higher moments from trends in mean or standard deviation and use bootstrap resampling to evaluate statistical significances. The application of the concept of the exceedance product to daily meteorological time series from Potsdam (1893 to 2005) and Prague-Klementinum (1775 to 2004) reveals that extremely cold winters occurred only until the mid-20th century, whereas warm winters show upward trends. These changes were significant in higher moments of the temperature distribution. In contrast, trends in summer temperature extremes (e.g., the 2003 European heatwave) can be explained by linear changes in mean or standard deviation. While precipitation at Potsdam does not show pronounced trends, dew point does exhibit a change from maximum extremes during the 1960s to minimum extremes during the 1970s.

Recovery of Waste Heat from Propellant Forced-Air Dry House

DTIC Science & Technology

1978-12-01

function of bulk air side film heat transfer coefficient and diffusivity 66 15. Dry house waste heat recovery system instrumentation 67 16. Sample data...inlet condition by, maintaining the exhaust temperature above the NG dew point. The set point is adjustable to accommodate various propel- lant and...system. In dry cycle operation, an overall energy recovery effectiveness of about 40% was measured for winter operation when the exhaust temperature

Measurement of evaporative water loss in small animals by dew-point hygrometry.

PubMed

Bernstein, M H; Hudson, D M; Stearns, J M; Hoyt, R W

1977-08-01

This paper presents the procedures and equations to be utilized for measurement of evaporative water loss (mw), by use of the dew-point hygrometer, in small animals exposed to air containing water vapor in an open-flow system. The system accounted accurately for the water evaporated from a bubble flask. In addition, hygrometric measurements of pulmocutaneous mw in pigeons (Columba livia, mean mass 0.31 kg) agreed closely with simultaneous gravimetric measurements, utilizing a desiccant in the sample stream, in a manner independently of air temperature (Ta, 20 or 40 degrees C), ambient water vapor pressure (PW, 4-16 10(2) Pa), or mw (5-66 mg-min-1). Evaporation in pigeons was independent of PW at 20 degrees C, but increased with decreasing PW at 40 degrees C, suggesting differences in ventilatory adjustments to changes in PW at the two temperatures.

Tropospheric profiles of wet refractivity and humidity from the combination of remote sensing data sets and measurements on the ground

NASA Astrophysics Data System (ADS)

Hurter, F.; Maier, O.

2013-11-01

We reconstruct atmospheric wet refractivity profiles for the western part of Switzerland with a least-squares collocation approach from data sets of (a) zenith path delays that are a byproduct of the GPS (global positioning system) processing, (b) ground meteorological measurements, (c) wet refractivity profiles from radio occultations whose tangent points lie within the study area, and (d) radiosonde measurements. Wet refractivity is a parameter partly describing the propagation of electromagnetic waves and depends on the atmospheric parameters temperature and water vapour pressure. In addition, we have measurements of a lower V-band microwave radiometer at Payerne. It delivers temperature profiles at high temporal resolution, especially in the range from ground to 3000 m a.g.l., though vertical information content decreases with height. The temperature profiles together with the collocated wet refractivity profiles provide near-continuous dew point temperature or relative humidity profiles at Payerne for the study period from 2009 to 2011. In the validation of the humidity profiles, we adopt a two-step procedure. We first investigate the reconstruction quality of the wet refractivity profiles at the location of Payerne by comparing them to wet refractivity profiles computed from radiosonde profiles available for that location. We also assess the individual contributions of the data sets to the reconstruction quality and demonstrate a clear benefit from the data combination. Secondly, the accuracy of the conversion from wet refractivity to dew point temperature and relative humidity profiles with the radiometer temperature profiles is examined, comparing them also to radiosonde profiles. For the least-squares collocation solution combining GPS and ground meteorological measurements, we achieve the following error figures with respect to the radiosonde reference: maximum median offset of relative refractivity error is -16% and quartiles are 5% to 40% for the lower troposphere. We further added 189 radio occultations that met our requirements. They mostly improved the accuracy in the upper troposphere. Maximum median offsets have decreased from 120% relative error to 44% at 8 km height. Dew point temperature profiles after the conversion with radiometer temperatures compare to radiosonde profiles as to: absolute dew point temperature errors in the lower troposphere have a maximum median offset of -2 K and maximum quartiles of 4.5 K. For relative humidity, we get a maximum mean offset of 7.3%, with standard deviations of 12-20%. The methodology presented allows us to reconstruct humidity profiles at any location where temperature profiles, but no atmospheric humidity measurements other than from GPS are available. Additional data sets of wet refractivity are shown to be easily integrated into the framework and strongly aid the reconstruction. Since the used data sets are all operational and available in near-realtime, we envisage the methodology of this paper to be a tool for nowcasting of clouds and rain and to understand processes in the boundary layer and at its top.

Frequency of urban building fires as related to daily weather conditions

Treesearch

Arthur R. Pirsko; Wallace L. Fons

1956-01-01

Daily weather elements of precipitation, wind, mean temperature, relative humidity, and dew-point temperature for selected urban areas (approximately 850,000 population) in the United States are statistically analyzed to determine their correlation with daily number of building fires. The frequency of urban building fires is found to be significantly correlated with...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

Propagation of sound through the Earth's atmosphere

NASA Technical Reports Server (NTRS)

Meredith, R. W.; Becher, J.

1983-01-01

The data collected at a pressure of one atmosphere for the different temperatures and relative humidities of the air-water vapor mixtures is summarized. The dew point hygrometer used in these measurements did not give reliable results for dew points much above the ambient room temperature. For this reason measurements were not attempted at the higher temperatures and humidities. Viscous wall losses in the resonant tube at 0 C so dominate the molecular relaxation of nitrogen, in the air-water vapor mixture, that reliable data could not be obtained using the free decay method in a resonant tube at one atmosphere. In an effort to obtain viable data at these temperatures, measurements were performed at a pressure of 10 atmospheres. Since the molecular relaxation peak is proportional to the pressure and the viscous losses are proportional to the inverse square root of the pressure the peak height should be measurable at the higher pressure. The tradeoff here is that at 10 atmospheres; the highest relative humidity attainable is 10 percent. The data collected at 10 atmospheres is also summarized.

Development of a new densimeter for the combined investigation of dew-point densities and sorption phenomena of fluid mixtures

NASA Astrophysics Data System (ADS)

Moritz, Katharina; Kleinrahm, Reiner; McLinden, Mark O.; Richter, Markus

2017-12-01

For the determination of dew-point densities and pressures of fluid mixtures, a new densimeter has been developed. The new apparatus is based on the well-established two-sinker density measurement principle with the additional capability of quantifying sorption effects. In the vicinity of the dew line, such effects cause a change in composition of the gas mixture under study, which can significantly distort accurate density measurements. The new experimental technique enables the accurate measurement of dew-point densities and pressures and the quantification of sorption effects at the same time.

MODIS Atmospheric Data Handler

NASA Technical Reports Server (NTRS)

Anantharaj, Valentine; Fitzpatrick, Patrick

2008-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) Atmosphere Data Handler software converts the HDF data to ASCII format, and outputs: (1) atmospheric profiles of temperature and dew point and (2) total precipitable water. Quality-control data are also considered in the export procedure.

Advances in thermal control and performance of the MMT M1 mirror

NASA Astrophysics Data System (ADS)

Gibson, J. D.; Williams, G. G.; Callahan, S.; Comisso, B.; Ortiz, R.; Williams, J. T.

2010-07-01

Strategies for thermal control of the 6.5-meter diameter borosilicate honeycomb primary (M1) mirror at the MMT Observatory have included: 1) direct control of ventilation system chiller setpoints by the telescope operator, 2) semiautomated control of chiller setpoints, using a fixed offset from the ambient temperature, and 3) most recently, an automated temperature controller for conditioned air. Details of this automated controller, including the integration of multiple chillers, heat exchangers, and temperature/dew point sensors, are presented here. Constraints and sanity checks for thermal control are also discussed, including: 1) mirror and hardware safety, 2) aluminum coating preservation, and 3) optimization of M1 thermal conditions for science acquisition by minimizing both air-to-glass temperature differences, which cause mirror seeing, and internal glass temperature gradients, which cause wavefront errors. Consideration is given to special operating conditions, such as high dew and frost points. Precise temperature control of conditioned ventilation air as delivered to the M1 mirror cell is also discussed. The performance of the new automated controller is assessed and compared to previous control strategies. Finally, suggestions are made for further refinement of the M1 mirror thermal control system and related algorithms.

Analysis of Multicomponent Adsorption Close to a Dew Point.

PubMed

Shapiro; Stenby

1998-10-15

We develop the potential theory of multicomponent adsorption close to a dew point. The approach is based on an asymptotic adsorption equation (AAE) which is valid in a vicinity of the dew point. By this equation the thickness of the liquid film is expressed through thermodynamic characteristics of the bulk phase. The AAE makes it possible to study adsorption in the regions of both the normal and the retrograde condensation. A simple correlation of the Kelvin radius for capillary condensation and the thickness of the adsorbed film is established. Numerical testing shows good agreement between the AAE and the direct calculations, even if the mixture is not close to a dew point. Copyright 1998 Academic Press.

Galvanizability of Advanced High-Strength Steels 1180TRIP and 1180CP

NASA Astrophysics Data System (ADS)

Kim, M. S.; Kwak, J. H.; Kim, J. S.; Liu, Y. H.; Gao, N.; Tang, N.-Y.

2009-08-01

In general, Si-bearing advanced high-strength steels (AHSS) possess excellent mechanical properties but poor galvanizability. The galvanizability of a transformation-induced plasticity (TRIP) steel 1180TRIP containing 2.2 pct Mn and 1.7 pct Si and a complex phase steel 1180CP containing 2.7 pct Mn and 0.2 pct Si was extensively studied using a galvanizing simulator. The steel coupons were annealed at fixed dew points in the simulator. The surface features of the as-annealed steel coupons, together with galvanized and galvannealed coatings, were carefully examined using a variety of advanced analysis techniques. It was found that various oxides formed on the surface of these steels, depending on the steel composition and on the dew point control. Coating quality was good at 0 °C dew point but deteriorated as the dew point decreased to -35 °C and -65 °C. Based on the findings, guidance was provided for improving galvanizability by adjusting the Mn:Si ratio in steel compositions according to the dew point.

Using dew points to estimate savings during a planned cooling shutdown

NASA Astrophysics Data System (ADS)

Friedlein, Matthew T.; Changnon, David; Musselman, Eric; Zielinski, Jeff

2005-12-01

In an effort to save money during the summer of 2003, Northern Illinois University (NIU) administrators instituted a four-day working week and stopped air conditioning buildings for the three-day weekends (Friday through Sunday). Shutting down the air conditioning systems caused a noticeable drop in electricity usage for that part of the campus that features in our study, with estimated total electricity savings of 1,268,492 kilowatt-hours or 17% of the average usage during that eight-week period. NIU's air conditioning systems, which relied on evaporative cooling to function, were sensitive to dew point levels. Greatest savings during the shutdown period occurred on days with higher dew points. An examination of the regional dew point climatology (1959 2003) indicated that the average summer daily dew point for 2003 was 14.9°C (58.8°F), which fell in the lowest 20% of the distribution. Based on the relationship between daily average dew points and electrical usage, a predictive model that could estimate electrical daily savings was created. This model suggests that electrical savings related to any future three-day shutdowns over summer could be much greater in more humid summers. Studies like this demonstrate the potential value of applying climatological information and of integrating this information into practical decision-making.

Using regression analysis to predict emergency patient volume at the Indianapolis 500 mile race.

PubMed

Bowdish, G E; Cordell, W H; Bock, H C; Vukov, L F

1992-10-01

Emergency physicians often plan and provide on-site medical care for mass gatherings. Most of the mass gathering literature is descriptive. Only a few studies have looked at factors such as crowd size, event characteristics, or weather in predicting numbers and types of patients at mass gatherings. We used regression analysis to relate patient volume on Race Day at the Indianapolis Motor Speedway to weather conditions and race characteristics. Race Day weather data for the years 1983 to 1989 were obtained from the National Oceanic and Atmospheric Administration. Data regarding patients treated on 1983 to 1989 Race Days were obtained from the facility hospital (Hannah Emergency Medical Center) data base. Regression analysis was performed using weather factors and race characteristics as independent variables and number of patients seen as the dependent variable. Data from 1990 were used to test the validity of the model. There was a significant relationship between dew point (which is calculated from temperature and humidity) and patient load (P less than .01). Dew point, however, failed to predict patient load during the 1990 race. No relationships could be established between humidity, sunshine, wind, or race characteristics and number of patients. Although higher dew point was associated with higher patient load during the 1983 to 1989 races, dew point was a poor predictor of patient load during the 1990 race. Regression analysis may be useful in identifying relationships between event characteristics and patient load but is probably inadequate to explain the complexities of crowd behavior and too simplified to use as a prediction tool.

Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

NASA Astrophysics Data System (ADS)

Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

2014-12-01

When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

Growth responses of male broilers subjected to increasing air velocities at high ambient temperatures and a high dew point.

PubMed

Dozier, W A; Lott, B D; Branton, S L

2005-06-01

This study examined live performance responses of male broilers to increasing air velocity of 120 and 180 m/min reared under high cyclic temperatures (25-35-25 degrees C) with a 23 degrees C dew point from 21 to 49 d. Birds were reared in an environmental facility containing 2 wind tunnels (4 pens/tunnel) and 6 floor pens (control). At 21 d, 53 birds were placed in each pen of the wind tunnels and control group, respectively, and growth performance was determined weekly. Increasing air velocity from 120 to 180 m/min improved BW and BW gain from 29 to 35, 36 to 42, and 43 to 49 d of age leading to a cumulative advantage of 287 g in BW gain and a 10-point difference in feed conversion from 21 to 49 d of age. Subjecting birds to air velocity improved growth rate, feed consumption, and feed conversion at each weekly interval from 28 to 49 d over the control birds. These results indicate that male broilers approximating 2.0 to 3.0 kg respond to an air velocity of 180 m/min when exposed to high cyclic temperatures.

Feedback dew-point sensor utilizing optimally cut plastic optical fibres

NASA Astrophysics Data System (ADS)

Hadjiloucas, S.; Irvine, J.; Keating, D. A.

2000-01-01

A plastic optical fibre reflectance sensor that makes full use of the critical angle of the fibres is implemented to monitor dew formation on a Peltier-cooled reflector surface. The optical configuration permits isolation of optoelectronic components from the sensing head and better light coupling between the reflector and the detecting fibre, giving a better signal of the onset of dew formation on the reflector. Continuous monitoring of the rate of change in reflectance as well as the absolute reflectance signals, the use of a novel polymethyl-methacrylate-coated hydrophobic film reflector on the Peltier element and the application of feedback around the point of dew formation, further reduces the possibility of contamination of the sensor head. Under closed-loop operation, the sensor is capable of cycling around the point of dew formation at a frequency of 2.5 Hz.

Effects of dew deposition on transpiration and carbon uptake in leaves

NASA Astrophysics Data System (ADS)

Gerlein-Safdi, C.; Koohafkan, M.; Chung, M.; Rockwell, F. E.; Thompson, S. E.; Caylor, K. K.

2017-12-01

Dew deposition occurs in ecosystems worldwide, even in the driest deserts and in times of drought. Although some species absorb dew water directly via foliar uptake, a ubiquitous effect of dew on plant water balance is the interference of dew droplets with the leaf energy balance, which increases leaf albedo and emissivity and decreases leaf temperature through dew evaporation. Dew deposition frequency and amount are expected to be affected by changing environmental conditions, with unknown consequences for plant water stress and ecosystem carbon, water and energy fluxes. Here we present a simple leaf energy balance that characterizes the effect of deposition and the evaporation of dew on leaf energy balance, transpiration, and carbon uptake. The model is driven by five common meteorological variables and shows very good agreement with leaf wetness sensor data from the Blue Oak Ranch Reserve in California. We explore the tradeoffs between energy, water, and carbon balances for leaves of different sizes across a range of relative humidity, wind speed, and air temperature conditions. Our results show significant water savings from transpiration suppression up to 30% for leaf characteristic lengths of 50 cm due to the decrease in leaf temperature. C. 25% of water savings from transpiration suppression in smaller leaves arise from the effect of dew droplets on leaf albedo. CO2 assimilation is decreased by up to 15% by the presence of dew, except for bigger leaves in windspeed conditions below 1 m/s when an increase in assimilation is expected.

Study of temperature, air dew point temperature and reactant flow effects on proton exchange membrane fuel cell performances using electrochemical spectroscopy and voltammetry techniques

NASA Astrophysics Data System (ADS)

Wasterlain, S.; Candusso, D.; Hissel, D.; Harel, F.; Bergman, P.; Menard, P.; Anwar, M.

A single PEMFC has been operated by varying the assembly temperature, the air dew point temperature and the anode/cathode stoichiometry rates with the aim to identify the parameters and combinations of factors affecting the cell performance. Some of the experiments were conducted with low humidified reactants (relative humidity of 12%). The FC characterizations tests have been conducted using in situ electrochemical methods based on load current and cell voltage signal analysis, namely: polarization curves, EIS measurements, cyclic and linear sweep voltammetries (CV and LSV). The impacts of the parameters on the global FC performances were observed using the polarization curves whereas EIS, CV and LSV test results were used to discriminate the different voltage loss sources. The test results suggest that some parameter sets allow maximal output voltages but can also induce material degradation. For instance, higher FC temperature and air flow values can induce significant electrical efficiency benefits, notably by increasing the reversible potential and the reaction kinetics. However, raising the cell temperature can also gradually dry the FC and increase the risk of membrane failure. LSV has also shown that elevated FC temperature and relative humidity can also accelerate the electrolyte degradation (i.e. slightly higher fuel crossover rate) and reduce the lifetime consequently.

USSR and Eastern Europe Scientific Abstracts, Engineering and Equipment, Number 36.

DTIC Science & Technology

1977-11-30

DEW POINT OF EXHAUST GASES FROM PULVERIZERS Moscow ELEKTRICHESKIYE STANTSII in Russian No 5, May 77 pp 7-9 MIKHAYLOV, N. M., and GLUSHKINA, B. S., All...moist coal may drop below the dew point and thus cause intensive corrosion of pipes as well as machinery. Sulfur oxides (especially SO3) contained...in the combustion products raise the dew point but, being completely adsorbed by ash and residual fuel particles, cannot serve as an effective

Dew point measurement technique utilizing fiber cut reflection

NASA Astrophysics Data System (ADS)

Kostritskii, S. M.; Dikevich, A. A.; Korkishko, Yu. N.; Fedorov, V. A.

2009-05-01

The fiber optical dew point hygrometer based on change of reflection coefficient for fiber cut has been developed and examined. We proposed and verified the model of condensation detector functioning principle. Experimental frost point measurements on air with different frost points have been performed.

Meteorologial Techniques (Revision 21 Feb 2007)

DTIC Science & Technology

2003-06-13

Dissipation of Stratus Using Mixing Ratio and Temperature ------------------------- 2-12 Figure 2-27 Tropopause Method of Forecasting Cirrus...2-51 Figure 2-70 Bright Band Identification Using the WSR-88D...convective clouds using surface dew-point depressions --------------------- 2-11 Table 2-5 Aircraft category type

High-temperature phase relations and thermodynamics in the iron-lead-sulfur system

NASA Astrophysics Data System (ADS)

Eric, R. Hurman; Ozok, Hakan

1994-01-01

The PbS activities in FeS-PbS liquid mattes were obtained at 1100 °C and 1200 °C by the dew-point method. Negative deviations were observed, and the liquid-matte solutions were modeled by the Krupkowski formalism. The liquid boundaries of the FeS-PbS phase diagram were derived from the model equations yielding a eutectic temperature of 842 °C at X Pbs = 0.46. A phase diagram of the pseudobinary FeS-PbS was also verified experimentally by quenching samples equilibrated in evacuated and sealed silica capsules. No terminal solid solution ranges could be found. Within the Fe-Pb-S ternary system, the boundaries of the immiscibility region together with the tie-line distributions were established at 1200 °C. Activities of Pb were measured by the dew-point technique along the metal-rich boundary of the miscibility gap. Activities of Fe, Pb, and S, along the miscibility gap were also calculated by utilizing the bounding binary thermodynamics, phase equilibria, and tie-lines.

Microclimate environmental parameters indexed for Sudden Oak death in Georgia and South Carolina

Treesearch

Pauline Spaine; William J. Otrosina; Stanley J. Zarnoch; Sharon V. Lumpkin

2008-01-01

We monitored Ericaceous habitat in Georgia and South Carolina for temperature, dew point and humidity ranges throughout a two year period. Temperature and humidity data were used to characterize their range in Georgia and South Carolina where potential SOD susceptible hosts occur. This data suggests risk for SOD development may be more widespread in southeastern forest...

Retrieving air humidity, global solar radiation, and reference evapotranspiration from daily temperatures: development and validation of new methods for Mexico. Part I: humidity

NASA Astrophysics Data System (ADS)

Lobit, P.; López Pérez, L.; Lhomme, J. P.; Gómez Tagle, A.

2017-07-01

This study evaluates the dew point method (Allen et al. 1998) to estimate atmospheric vapor pressure from minimum temperature, and proposes an improved model to estimate it from maximum and minimum temperature. Both methods were evaluated on 786 weather stations in Mexico. The dew point method induced positive bias in dry areas but also negative bias in coastal areas, and its average root mean square error for all evaluated stations was 0.38 kPa. The improved model assumed a bi-linear relation between estimated vapor pressure deficit (difference between saturated vapor pressure at minimum and average temperature) and measured vapor pressure deficit. The parameters of these relations were estimated from historical annual median values of relative humidity. This model removed bias and allowed for a root mean square error of 0.31 kPa. When no historical measurements of relative humidity were available, empirical relations were proposed to estimate it from latitude and altitude, with only a slight degradation on the model accuracy (RMSE = 0.33 kPa, bias = -0.07 kPa). The applicability of the method to other environments is discussed.

Control of membrane permeability in air-stable droplet interface bilayers

DOE PAGES

Mruetusatorn, Prachya; Polizos, Georgios; Datskos, Panos G.; ...

2015-03-19

Air-stable droplet interface bilayers (airDIBs) on oil-infused surfaces are versatile model membranes for synthetic biology applications, including biosensing of airborne species. However, air-DIBs are subject to evaporation, which can, over time, destabilize them and reduce their useful lifetime compared to traditional DIBs that are fully submerged in oil. Here, we show that lifetimes of air-DIBs can be extended by as much as an order of magnitude by maintaining them at a temperature just above the dew point. We find that raising the temperature from near the dew point (7 C at 38.5 % relative humidity) to room temperature results inmore » loss of water molecules of hydration from the polar head groups of the lipid bilayer membrane due to evaporation in an irreversible process that increases the overall entropy of the system. This dehydration transition affects primarily the bilayer resistance, by increasing ion permeability through the increasingly disordered polar head group region of the bilayer. Temperature and/or relative humidity are conveniently tunable parameters for controlling the stability and composition of air-DIBs membranes, while still allowing for operation in ambient environments.« less

AVGAS/AUTOGAS (Aviation Gasoline/Automobile Gasoline) Comparison. Winter Grade Fuels.

DTIC Science & Technology

1986-07-01

mass MAP Manifold pressure - inHg MON Motor Octane Number NIPER National Institute of Petroleum and Energy Resources Pamb Ambient pressure - inHg...pressure - psig si Sea level (used as a subscript) STC Supplemental Type Certificate Tamb Ambient temperature - degC or degF Tdew Dew point - degC or degF...temperature deg C #2 exhaust gas temperature deg C #3 exhaust gas temperature deg C #4 exhaust gas temperature deg C Ambient air temperature deg C 6

The influence of dew point during annealing on the power loss of electrical steel sheets

NASA Astrophysics Data System (ADS)

Broddefalk, Arvid; Jenkins, Keith; Silk, Nick; Lindenmo, Magnus

Decarburization is a necessary part of the processing of electrical steels if their carbon content is above a certain level. The process is usually carried out in a wet hydrogen-nitrogen atmosphere. Having a high dew point has a negative influence on the power loss, though. This is due to oxidation of the steel, which hinders domain wall motion near the surface. In this study, an increase of the power loss was only observed at a fairly high dew point (>20 °C). It was also only at these high dew points where a subsurface oxide layer was observed. The surfaces of samples with and without this layer were etched in steps. The magnetic properties of the etched samples corresponded well with the expected behavior based on GDOES profiles of the samples.

Spatial interpolation of hourly precipitation and dew point temperature for the identification of precipitation phase and hydrologic response in a mountainous catchment

NASA Astrophysics Data System (ADS)

Garen, D. C.; Kahl, A.; Marks, D. G.; Winstral, A. H.

2012-12-01

In mountainous catchments, it is well known that meteorological inputs, such as precipitation, air temperature, humidity, etc. vary greatly with elevation, spatial location, and time. Understanding and monitoring catchment inputs is necessary in characterizing and predicting hydrologic response to these inputs. This is true all of the time, but it is the most dramatically critical during large storms, when the input to the stream system due to rain and snowmelt creates the potential for flooding. Besides such crisis events, however, proper estimation of catchment inputs and their spatial distribution is also needed in more prosaic but no less important water and related resource management activities. The first objective of this study is to apply a geostatistical spatial interpolation technique (elevationally detrended kriging) to precipitation and dew point temperature on an hourly basis and explore its characteristics, accuracy, and other issues. The second objective is to use these spatial fields to determine precipitation phase (rain or snow) during a large, dynamic winter storm. The catchment studied is the data-rich Reynolds Creek Experimental Watershed near Boise, Idaho. As part of this analysis, precipitation-elevation lapse rates are examined for spatial and temporal consistency. A clear dependence of lapse rate on precipitation amount exists. Certain stations, however, are outliers from these relationships, showing that significant local effects can be present and raising the question of whether such stations should be used for spatial interpolation. Experiments with selecting subsets of stations demonstrate the importance of elevation range and spatial placement on the interpolated fields. Hourly spatial fields of precipitation and dew point temperature are used to distinguish precipitation phase during a large rain-on-snow storm in December 2005. This application demonstrates the feasibility of producing hourly spatial fields and the importance of doing so to support an accurate determination of precipitation phase for assessing catchment hydrologic response to the storm.

Dew point fast measurement in organic vapor mixtures using quartz resonant sensor

NASA Astrophysics Data System (ADS)

Nie, Jing; Liu, Jia; Meng, Xiaofeng

2017-01-01

A fast dew point sensor has been developed for organic vapor mixtures by using the quartz crystal with sensitive circuits. The sensor consists of the quartz crystal and a cooler device. Proactive approach is taken to produce condensation on the surface of the quartz crystal, and it will lead to a change in electrical features of the quartz crystal. The cessation of oscillation was measured because this phenomenon is caused by dew condensation. Such a phenomenon can be used to detect the dew point. This method exploits the high sensitivity of the quartz crystal but without frequency measurement and also retains the stability of the resonant circuit. It is strongly anti-interfered. Its performance was evaluated with acetone-methanol mixtures under different pressures. The results were compared with the dew points predicted from the universal quasi-chemical equation to evaluate the performance of the proposed sensor. Though the maximum deviations of the sensor are less than 1.1 °C, it still has a fast response time with a recovery time of less than 10 s, providing an excellent dehumidifying performance.

Dew point fast measurement in organic vapor mixtures using quartz resonant sensor.

PubMed

Nie, Jing; Liu, Jia; Meng, Xiaofeng

2017-01-01

A fast dew point sensor has been developed for organic vapor mixtures by using the quartz crystal with sensitive circuits. The sensor consists of the quartz crystal and a cooler device. Proactive approach is taken to produce condensation on the surface of the quartz crystal, and it will lead to a change in electrical features of the quartz crystal. The cessation of oscillation was measured because this phenomenon is caused by dew condensation. Such a phenomenon can be used to detect the dew point. This method exploits the high sensitivity of the quartz crystal but without frequency measurement and also retains the stability of the resonant circuit. It is strongly anti-interfered. Its performance was evaluated with acetone-methanol mixtures under different pressures. The results were compared with the dew points predicted from the universal quasi-chemical equation to evaluate the performance of the proposed sensor. Though the maximum deviations of the sensor are less than 1.1 °C, it still has a fast response time with a recovery time of less than 10 s, providing an excellent dehumidifying performance.

Measurement of dew droplets in initial deposition at dew point by using a phase-shift interference microscope

NASA Astrophysics Data System (ADS)

Matsumoto, Shigeaki; Toyooka, Satoru; Hoshino, Mitsuo

2002-09-01

In order to measure the total mass per unit area of dew droplets deposited on a metal plate in the dew-point hygrometer, the shape of a dew droplet deposited on a copper plate was measured accurately by using an interference microscope that employed a phase-shift technique. The microscope was constructed by adding a piezoelectric transducer to an usual interference microscope. A simple method that uses a conventional speaker horn and an optical fiber cable was introduced to depress speckle noise. The shape of a dew droplet deposited on the copper plate surface with 0.1 μm in average roughness was measured with an accuracy of +/-3nm. The mass of a dew droplet could be calculated numerically from the volume of its shape and was of the order of 10-9 g. The total mass of dew droplets deposited per unit area and the deposition velocity were obtained under a gentle wind. The total mass was the order of 10-5 g/cm2 at the beginning of deposition and the deposition velocity was ranged from 2x10-6 to 6x10-5 g/cm2.min.

Nitric Oxide Measurement Study. Volume II. Probe Methods,

DTIC Science & Technology

1980-05-01

case of the Task I study, it should be pointed out that at lower gas temperatures where much of the study was performed, the mass flow through the...third body as pointed out by Matthews, et al. (1977) but also dependent on the viscosity of the sampled gas for standard commercial units (Folsom and...substantially above the dew point (based on the maximum pressure in the sampling system and the initial water concentration) or (2) sample line and

Removal mechanisms of dew via self-propulsion off the gecko skin

PubMed Central

Watson, Gregory S.; Schwarzkopf, Lin; Cribb, Bronwen W.; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A.

2015-01-01

Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. PMID:25762647

Atmospheric Models For Over-Ocean Propagation Loss

DTIC Science & Technology

2015-08-24

Radiosonde balloons are launched daily at selected loca- tions, and measure temperature, dew point temperature, and air pressure as they ascend. Radiosondes...different times of year and locations. The result was used to estimate high-reliability SHF/EHF air -to-surface radio link performance in a maritime...environment. I. INTRODUCTION Air -to-surface radio links differ from typical satellite com- munications links in that the path elevation angles are lower

Efficiency and temperature dependence of water removal by membrane dryers

NASA Technical Reports Server (NTRS)

Leckrone, K. J.; Hayes, J. M.

1997-01-01

The vapor pressure of water in equilibrium with sorption sites within a Nafion membrane is given by log P(WN) = -3580/T + 10.01, where P(WN) is expressed in Torr and T is the membrane temperature, in kelvin. The efficiency of dryers based on selective permeation of water through Nafion can thus be enhanced by cooling the membrane. Residual water in effluents exceeds equilibrium levels if insufficient time is allowed for water to diffuse to the membrane surface as gas passes through the dryer. For tubular configurations, this limitation can be avoided if L > or = Fc(10(3.8)/120 pi D), where L is the length of the tubular membrane, in centimeters, Fc is the gas flow rate, in mL/ min, and D is the diffusion coefficient for water in the carrier gas at the operating temperature of the dryer, in cm2/s. An efficient dryer that at room temperature dries gas to a dew point of -61 degrees C is described; the same dryer maintained at 0 degrees C yields a dew point of -80 degrees C and removes water as effectively as Mg(ClO4)2 or a dry ice/acetone slush. The use of Nafion membranes to construct devices capable of delivering gas streams with low but precisely controlled humidities is discussed.

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2010 CFR

2010-07-01

...-test and post-test values) kPa Pv Saturation pressure at dew point temperature kPa Ra Relative humidity...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment... Percent torque related to maximum torque for the test mode % mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2014 CFR

2014-07-01

...-test and post-test values) kPa Pv Saturation pressure at dew point temperature kPa Ra Relative humidity...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment... Percent torque related to maximum torque for the test mode % mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2011 CFR

2011-07-01

...-test and post-test values) kPa Pv Saturation pressure at dew point temperature kPa Ra Relative humidity...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment... Percent torque related to maximum torque for the test mode % mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2012 CFR

2012-07-01

...-test and post-test values) kPa Pv Saturation pressure at dew point temperature kPa Ra Relative humidity...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment... Percent torque related to maximum torque for the test mode % mass Pollutant mass flow g/h nd, i Engine...

40 CFR Appendix A to Subpart D of... - Tables

Code of Federal Regulations, 2013 CFR

2013-07-01

...-test and post-test values) kPa Pv Saturation pressure at dew point temperature kPa Ra Relative humidity...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Test Equipment... Percent torque related to maximum torque for the test mode % mass Pollutant mass flow g/h nd, i Engine...

An Examination of a Simulated Microburst Flow as Sensed by a Single Doppler Radar

DTIC Science & Technology

1988-01-01

34 macrobursts " and "microbursts" dependent upon whether the downburst diameter was larger or smaller than 4 km. Although his theories initally met some...variables, unlike a macroburst which is accompanied by a dome of high pressure, gusty winds, and abruptly cooler temperatures. Ambient and dew- point

Comparisons between Nimbus 6 satellite and rawinsonde soundings for several geographical areas

NASA Technical Reports Server (NTRS)

Cheng, N. M.; Scoggins, J. R.

1981-01-01

Good agreement between satellite and weighted (linearly interpolated) rawinsonde temperature and temperature derived parameters was found in most instances with the poorest agreement either near the tropopause region or near the ground. However, satellite moisture data are highly questionable. The smallest discrepancy between satellite and weighted mean rawinsonde temperature and parameters derived from temperature was found over water and the largest discrepancy was found over mountains. Cumulative frequency distributions show that discrepancies between satellite and rawinsonde data can be represented by a normal distribution except for dew point temperature.

Use of dew-point detection for quantitative measurement of sweating rate

NASA Technical Reports Server (NTRS)

Brengelmann, G. L.; Mckeag, M.; Rowell, L. B.

1975-01-01

A method of measuring sweat rate (SR) based on detection of dew point (DP) is proposed which has advantages that may be attractive to other laboratories concerned with recording SR from selected areas of skin. It is similar to other methods in that dry gas is passed through a capsule which isolates several square centimeters of skin surface. The difference is in the means of determining how much gaseous water is carried off in the effluent moist gas. The DP detector used is free of the drawbacks of previous devices. DP is obtained through the fundamental technique of determining the temperature at which condensate forms on a mirror. Variations in DP are tracked rapidly, and accurately (+ or - 0.8 C nominal, sensitivity + or - 0.05 C) over a wide range ( -40 C to +50 C) without measurable hysteresis. The detector asembly is rugged and readily opened for cleaning and inspection.

Evaluation of the Long-Term Stability and Temperature Coefficient of Dew-Point Hygrometers

NASA Astrophysics Data System (ADS)

Benyon, R.; Vicente, T.; Hernández, P.; De Rivas, L.; Conde, F.

2012-09-01

The continuous quest for improved specifications of optical dew-point hygrometers has raised customer expectations on the performance of these devices. In the absence of a long calibration history, users with a limited prior experience in the measurement of humidity, place reliance on manufacturer specifications to estimate long-term stability. While this might be reasonable in the case of measurement of electrical quantities, in humidity it can lead to optimistic estimations of uncertainty. This article reports a study of the long-term stability of some hygrometers and the analysis of their performance as monitored through regular calibration. The results of the investigations provide some typical, realistic uncertainties associated with the long-term stability of instruments used in calibration and testing laboratories. Together, these uncertainties can help in establishing initial contributions in uncertainty budgets, as well as in setting the minimum calibration requirements, based on the evaluation of dominant influence quantities.

Drier Air, Lower Temperatures, and Triggering of Paroxysmal Atrial Fibrillation

PubMed Central

Nguyen, Jennifer L.; Link, Mark S.; Luttmann-Gibson, Heike; Laden, Francine; Schwartz, Joel; Wessler, Benjamin S.; Mittleman, Murray A.; Gold, Diane R.; Dockery, Douglas W.

2015-01-01

Background The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes. Methods Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity). Results Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m3 decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker. Conclusions Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes. PMID:25756220

Inventory of File naefs_geavg.t12z.ndgd_conusf18.grib2

Science.gov Websites

fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 18 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 18 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 18 hour fcst Dew Point Temperature [K] ens-mean 005 10 m above ground UGRD 18 hour fcst U-Component of Wind [m/s] ens

Inventory of File naefs_geavg.t12z.ndgd_conusf30.grib2

Science.gov Websites

fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 30 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 30 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 30 hour fcst Dew Point Temperature [K] ens-mean 005 10 m above ground UGRD 30 hour fcst U-Component of Wind [m/s] ens

Inventory of File naefs_geavg.t12z.ndgd_alaskaf24.grib

Science.gov Websites

fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 24 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 24 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 24 hour fcst Dew Point Temperature [K] ens-mean 005 10 m above ground UGRD 24 hour fcst U-Component of Wind [m/s] ens

Inventory of File naefs_geavg.t12z.ndgd_alaskaf36.grib

Science.gov Websites

fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 36 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 36 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 36 hour fcst Dew Point Temperature [K] ens-mean 005 10 m above ground UGRD 36 hour fcst U-Component of Wind [m/s] ens

Portable Dew Point Mass Spectrometry System for Real-Time Gas and Moisture Analysis

NASA Technical Reports Server (NTRS)

Arkin, C.; Gillespie, Stacey; Ratzel, Christopher

2010-01-01

A portable instrument incorporates both mass spectrometry and dew point measurement to provide real-time, quantitative gas measurements of helium, nitrogen, oxygen, argon, and carbon dioxide, along with real-time, quantitative moisture analysis. The Portable Dew Point Mass Spectrometry (PDP-MS) system comprises a single quadrupole mass spectrometer and a high vacuum system consisting of a turbopump and a diaphragm-backing pump. A capacitive membrane dew point sensor was placed upstream of the MS, but still within the pressure-flow control pneumatic region. Pressure-flow control was achieved with an upstream precision metering valve, a capacitance diaphragm gauge, and a downstream mass flow controller. User configurable LabVIEW software was developed to provide real-time concentration data for the MS, dew point monitor, and sample delivery system pressure control, pressure and flow monitoring, and recording. The system has been designed to include in situ, NIST-traceable calibration. Certain sample tubing retains sufficient water that even if the sample is dry, the sample tube will desorb water to an amount resulting in moisture concentration errors up to 500 ppm for as long as 10 minutes. It was determined that Bev-A-Line IV was the best sample line to use. As a result of this issue, it is prudent to add a high-level humidity sensor to PDP-MS so such events can be prevented in the future.

The Application of Synoptic Weather Forecasting Rules to Selected Weather Situations in the United States.

ERIC Educational Resources Information Center

Kohler, Fred E.

The document describes the use of weather maps and data in teaching introductory college courses in synoptic meteorology. Students examine weather changes at three-hour intervals from data obtained from the "Monthly Summary of Local Climatological Data." Weather variables in the local summary include sky cover, air temperature, dew point, relative…

Gela, Italy, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1983-11-03

ADDRESS I2 REPORT DATE USAFETAC/ CBD 3 Nov 83 Air Weather Service (MAC) 13 NUMBER OF PAGES Scott AFB IL 62225 p. _ _ _0 r4 MONITORING AGENCY NAME & ADDRESS...temperature Lombined; tuid again for dry-bulb, wet-bulb, and dew-point tempera- tures separately. Total observations for thc .;e four Items is also

A frost formation model and its validation under various experimental conditions

NASA Technical Reports Server (NTRS)

Dietenberger, M. A.

1982-01-01

A numerical model that was used to calculate the frost properties for all regimes of frost growth is described. In the first regime of frost growth, the initial frost density and thickness was modeled from the theories of crystal growth. The 'frost point' temperature was modeled as a linear interpolation between the dew point temperature and the fog point temperature, based upon the nucleating capability of the particular condensing surfaces. For a second regime of frost growth, the diffusion model was adopted with the following enhancements: the generalized correlation of the water frost thermal conductivity was applied to practically all water frost layers being careful to ensure that the calculated heat and mass transfer coefficients agreed with experimental measurements of the same coefficients.

Removal mechanisms of dew via self-propulsion off the gecko skin.

PubMed

Watson, Gregory S; Schwarzkopf, Lin; Cribb, Bronwen W; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A

2015-04-06

Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

High Response Dew Point Measurement System for a Supersonic Wind Tunnel

NASA Technical Reports Server (NTRS)

Blumenthal, Philip Z.

1996-01-01

A new high response on-line measurement system has been developed to continuously display and record the air stream dew point in the NASA Lewis 10 x 10 supersonic wind tunnel. Previous instruments suffered from such problems as very slow response, erratic readings, and high susceptibility to contamination. The system operates over the entire pressure level range of the 10 x 10 SWT, from less than 2 psia to 45 psia, without the need for a vacuum pump to provide sample flow. The system speeds up tunnel testing, provides large savings in tunnel power costs and provides the dew point input for the data-reduction subroutines which calculate test section conditions.

Surface acoustic wave transducer used for determination of the dew point in measurements of air relative humidity

NASA Astrophysics Data System (ADS)

Golebiowski, Jacek

1995-06-01

The devices to the measurement of air relative humidity with the surface acoustic wave transducers were presented. The relative humidity of air were measured by the determination of the dew point. The results of the investigations that were carried out were described and discussed.

Pulse Detonation Engine Thrust Tube Heat Exchanger for Flash Vaporization and Supercritical Heating of JP-8

DTIC Science & Technology

2005-03-01

47 Figure 21. Construction of the long heat exchanger with helical rod welded in place.... 48 Figure 22. Heat exchanger...not at a temperature at or above the dew point temperature of the mixture, some of the fuel in the mixture will re- condense . The concept of...diao (25) Where kamb = Thermal conductivity of the air [W/(m-K)] Nufc = Nusselt number for free convection The Nussult number

A Calibration Facility for Dew Point in Air up to 1 MPa

NASA Astrophysics Data System (ADS)

Carroll, P. A.; Bell, S. A.; Stevens, M.

2015-12-01

The provision of primary dew-point standards for humidified air and nitrogen at atmospheric pressure is well established, and measurement traceability to these standards provides confidence in a vast number of air humidity measurements. However, hygrometers are used industrially at a wide range of pressures. Both the performance of hygrometers and the properties of humid gases are known to vary with gas pressure. The pressure-dependence of gas non-ideality for air-water mixtures (water-vapor enhancement factor) is well enough known at moderate pressures, but there remains a need to characterize hygrometers at the pressure of use. To address this, a humidity calibration capability of wider scope is under development at the UK National Physical Laboratory (NPL). As an initial stage in the development of this capability, a humidity standard generating air or nitrogen in the dew-point range from -60° C to +10° C, at pressures up to 1 MPa (10 bar) has been validated for the calibration of hygrometers. The expanded uncertainty of the dew-point generator in this range with a coverage factor k= 2 is ± 0.07° C.

Relation of Total and Cardiovascular Death Rates to Climate System, Temperature, Barometric Pressure, and Respiratory Infection.

PubMed

Schwartz, Bryan G; Qualls, Clifford; Kloner, Robert A; Laskey, Warren K

2015-10-15

A distinct seasonal pattern in total and cardiovascular death rates has been reported. The factors contributing to this pattern have not been fully explored. Seven locations (average total population 71,354,000) were selected where data were available including relatively warm, cold, and moderate temperatures. Over the period 2004 to 2009, there were 2,526,123 all-cause deaths, 838,264 circulatory deaths, 255,273 coronary heart disease deaths, and 135,801 ST-elevation myocardial infarction (STEMI) deaths. We used time series and multivariate regression modeling to explore the association between death rates and climatic factors (temperature, dew point, precipitation, barometric pressure), influenza levels, air pollution levels, hours of daylight, and day of week. Average seasonal patterns for all-cause and cardiovascular deaths were very similar across the 7 locations despite differences in climate. After adjusting for multiple covariates and potential confounders, there was a 0.49% increase in all-cause death rate for every 1°C decrease. In general, all-cause, circulatory, coronary heart disease and STEMI death rates increased linearly with decreasing temperatures. The temperature effect varied by location, including temperature's linear slope, cubic fit, positional shift on the temperature axis, and the presence of circulatory death increases in locally hot temperatures. The variable effect of temperature by location suggests that people acclimatize to local temperature cycles. All-cause and circulatory death rates also demonstrated sizable associations with influenza levels, dew point temperature, and barometric pressure. A greater understanding of how climate, temperature, and barometric pressure influence cardiovascular responses would enhance our understanding of circulatory and STEMI deaths. Copyright © 2015 Elsevier Inc. All rights reserved.

Air drying of softwood lumber, Fairbanks, Alaska.

Treesearch

George R Sampson; Forrest A. Ruppert

1985-01-01

Air-drying rates for two stacks of 2-inch-thick white spruce were observed in the Fairbanks area during summer 1982. The air-drying rate for the same size lumber was also observed during winter 1982-83. Very little drying occurred during the winter. Drying rates in summer were correlated with average daily temperature and average daily dew point to derive predictive...

Operating manual for the RRL 8 channel data logger

NASA Technical Reports Server (NTRS)

Paluch, E. J.; Shelton, J. D.; Gardner, C. S.

1979-01-01

A data collection device which takes measurements from external sensors at user specified time intervals is described. Three sensor ports are dedicated to temperature, air pressure, and dew point. Five general purpose sensor ports are provided. The user specifies when the measurements are recorded as well as when the information is read or stored in a minicomputer or a paper tape.

Water Resources Data for Illinois - Water Year 2005 (Includes Historical Data)

USGS Publications Warehouse

LaTour, J.K.; Weldon, E.A.; Dupre, D.H.; Halfar, T.M.

2006-01-01

This annual Water-Data Report for Illinois contains current water year (Oct. 1, 2004, to Sept. 30, 2005) and historical data of discharge, stage, water quality and biology of streams; stage of lakes and reservoirs; levels and quality of ground water; and records of precipitation, air temperature, dew point, solar radiation, and wind speed. The current year's (2005) data provided in this report include (1) discharge for 182 surface-water gaging stations and for 9 crest-stage partial-record stations; (2) stage for 33 surface-water gaging stations; (3) water-quality records for 10 surface-water stations; (4) sediment-discharge records for 14 surface-water stations; (5) water-level records for 98 ground-water wells; (6) water-quality records for 17 ground-water wells; (7) precipitation records for 48 rain gages; (8) records of air temperature, dew point, solar radiation and wind speed for 1 meteorological station; and (9) biological records for 6 sample sites. Also included are miscellaneous data collected at various sites not in the systematic data-collection network. Data were collected and compiled as a part of the National Water Information System (NWIS) maintained by the U.S. Geological Survey in cooperation with Federal, State, and local agencies.

Predicting the spatial distribution of Ochlerotatus albifasciatus (Diptera: Culicidae) abundance with NOAA imagery.

PubMed

Gleiser, R M; Gorla, D E

2007-12-01

Ochlerotatus albifasciatus is a vector of western equine encephalomyelitis in Argentina and a nuisance mosquito affecting beef and dairy production. The objective of this study was to analyze whether environmental proxy data derived from 1 km resolution NOAA-AVHRR images could be useful as a rapid tool for locating areas with higher potential for Oc. albifasciatus activity at a regional scale. Training sites for mosquito abundance categories were 3.3x3.3 km polygons over sampling sites. Abundance was classified into two categories according to a proposed threshold for economic losses. Data of channels 1, 2, 4 and 5 were used to calculate five biophysical variables: normalized differences vegetation index (NDVI), land surface temperature, total precipitable water, dew point and vapour saturation deficit. A discriminant analysis correctly classified 100% of the areas predicted to be above or below the economic threshold of 2500 mosquitoes per night of capture, respectively. Components of the NDVI, the total precipitable water and the dew point temperature contributed most to the function value. The results suggest that environmental data derived from AVHRR-NOAA could be useful for rapidly identifying adequate areas for mosquito development or activity.

The effects of meteorological factors on the occurrence of Ganoderma sp. spores in the air

NASA Astrophysics Data System (ADS)

Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

2011-03-01

Ganoderma sp. is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we analysed fungal spore circulation in Szczecin, Poland, and its dependence on meteorological conditions. Statistical models for the airborne spore concentrations of Ganoderma sp.—one of the most abundant fungal taxa in the area—were developed. Aerobiological sampling was conducted over 2004-2008 using a volumetric Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation, maximum and average wind speed, relative humidity and maximum, minimum, average and dew point temperatures. These data were used as the explaining variables. Due to the non-linearity and non-normality of the data set, the applied modelling techniques were artificial neural networks (ANN) and mutlivariate regression trees (MRT). The obtained classification and MRT models predicted threshold conditions above which Ganoderma sp. appeared in the air. It turned out that dew point temperature was the main factor influencing the presence or absence of Ganoderma sp. spores. Further analysis of spore seasons revealed that the airborne fungal spore concentration depended only slightly on meteorological factors.

The impact of time and field conditions on brown bear (Ursus arctos) faecal DNA amplification

USGS Publications Warehouse

Murphy, M.A.; Kendall, K.C.; Robinson, A.; Waits, L.P.

2007-01-01

To establish longevity of faecal DNA samples under varying summer field conditions, we collected 53 faeces from captive brown bears (Ursus arctos) on a restricted vegetation diet. Each faeces was divided, and one half was placed on a warm, dry field site while the other half was placed on a cool, wet field site on Moscow Mountain, Idaho, USA. Temperature, relative humidity, and dew point data were collected on each site, and faeces were sampled for DNA extraction at <1, 3, 6, 14, 30, 45, and 60 days. Faecal DNA sample viability was assessed by attempting PCR amplification of a mitochondrial DNA (mtDNA) locus (???150 bp) and a nuclear DNA (nDNA) microsatellite locus (180-200 bp). Time in the field, temperature, and dew point impacted mtDNA and nDNA amplification success with the greatest drop in success rates occurring between 1 and 3 days. In addition, genotyping errors significantly increased over time at both field sites. Based on these results, we recommend collecting samples at frequent transect intervals and focusing sampling efforts during drier portions of the year when possible. ?? 2007 Springer Science+Business Media, Inc.

Sensitive skin at menopause; dew point and electrometric properties of the stratum corneum.

PubMed

Paquet, F; Piérard-Franchimont, C; Fumal, I; Goffin, V; Paye, M; Piérard, G E

1998-01-12

A number of menopausal women experience skin sensitive to various environmental threats. Two panels of 15 menopausal women on or without HRT were compared. We studied the response of their stratum corneum to variations in environmental humidity, either in air or in response to an emollient. Environment dew point and electrometric measurements on the skin were recorded to search for correlations. Data show that the baseline stratum corneum hydration is influenced by the dew point. HRT improves the barrier function of the skin. The use of emollient further extends the improvement in the functional properties of skin in menopausal women. Both HRT and an emollient can counteract in part some of the deleterious effects of cold and dry weather.

Investigation on the pinch point position in heat exchangers

NASA Astrophysics Data System (ADS)

Pan, Lisheng; Shi, Weixiu

2016-06-01

The pinch point is important for analyzing heat transfer in thermodynamic cycles. With the aim to reveal the importance of determining the accurate pinch point, the research on the pinch point position is carried out by theoretical method. The results show that the pinch point position depends on the parameters of the heat transfer fluids and the major fluid properties. In most cases, the pinch point locates at the bubble point for the evaporator and the dew point for the condenser. However, the pinch point shifts to the supercooled liquid state in the near critical conditions for the evaporator. Similarly, it shifts to the superheated vapor state with the condensing temperature approaching the critical temperature for the condenser. It even can shift to the working fluid entrance of the evaporator or the supercritical heater when the heat source fluid temperature is very high compared with the absorbing heat temperature. A wrong position for the pinch point may generate serious mistake. In brief, the pinch point should be founded by the iterative method in all conditions rather than taking for granted.

Daily indoor-to-outdoor temperature and humidity relationships: a sample across seasons and diverse climatic regions

PubMed Central

Nguyen, Jennifer L.; Dockery, Douglas W.

2015-01-01

The health consequences of heat and cold are usually evaluated based on associations with outdoor measurements at the nearest weather reporting station. However, people in the developed world spend little time outdoors, especially during extreme temperature events. We examined the association between indoor and outdoor temperature and humidity in a range of climates. We measured indoor temperature, apparent temperature, relative humidity, dew point, and specific humidity (a measure of moisture content in air) for one calendar year (2012) in a convenience sample of eight diverse locations ranging from the equatorial region (10°N) to the Arctic (64°N). We then compared the indoor conditions to outdoor values recorded at the nearest airport weather station. We found that the shape of the indoor-to-outdoor temperature and humidity relationships varied across seasons and locations. Indoor temperatures showed little variation across season and location. There was large variation in indoor relative humidity between seasons and between locations which was independent of outdoor, airport measurements. On the other hand, indoor specific humidity, and to a lesser extent dew point, tracked with outdoor, airport measurements both seasonally and between climates, across a wide range of outdoor temperatures. Our results suggest that, depending on the measure, season, and location, outdoor weather measurements can be reliably used to represent indoor exposures and that, in general, outdoor measures of actual moisture content in air better capture indoor exposure than temperature and relative humidity. Therefore, absolute measures of water vapor should be examined in conjunction with other measures (e.g. temperature, relative humidity) in studies of the effect of weather and climate on human health. PMID:26054827

A field investigation and numerical simulation of coastal fog

NASA Technical Reports Server (NTRS)

Mack, E. J.; Eadie, W. J.; Rogers, C. W.; Kocmond, W. C.; Pilie, R. J.

1973-01-01

A field investigation of the microphysical and micrometeorological features of fogs occurring near Los Angeles and Vandenberg, California was conducted. Observations of wind speed and direction, temperature, dew point, vertical wind velocity, dew deposition, drop-size distribution, liquid water content, and haze and cloud nucleus concentration were obtained. These observations were initiated in late evening prior to fog formation and continued until the time of dissipation in both advection and radiation fogs. Data were also acquired in one valley fog and several dense haze situations. The behavior of these parameters prior to and during fog are discussed in detail. A two-dimensional numerical model was developed to investigate the formation and dissipation of advection fogs under the influence of horizontal variations in surface temperature. The model predicts the evolution of potential temperature, water vapor content, and liquid water content in a vertical plane as determined by vertical turbulent transfer and horizontal advection. Results are discussed from preliminary numerical experiments on the formation of warm-air advection fog and dissipation by natural and artificial heating from the surface.

Temperature and relative humidity distributions in a medium-size administrative town in southwest Nigeria.

PubMed

Akinbode, O M; Eludoyin, A O; Fashae, O A

2008-04-01

This study was carried out in one of the medium-sized public administrative towns in the southwestern part of Nigeria. Its aim is to highlight the effect of spatial distribution of settlements, population, and socio-economic activities on urban air temperature and humidity in the town. Temperature and relative humidity data from 1992 to 2001 were obtained from three meteorological stations in Akure, the Administrative Capital of Ondo State, Nigeria. The stations are located within the Federal Ministry of Aviation, Akure Airport (FMA), Federal University of Technology, Akure (FUTA) and Federal School of Agriculture (SOA). Air temperature and relative humidity measurements were also obtained from 27 points, which were cited to include road junctions, markets, built up areas, etc., using sling psychrometer. The data were subsequently analysed for spatial and temporal variations using statistical packages (SPSS and Microsoft Excel) and isolines. Actual vapour pressure and dew point temperature were computed using Magnus conversion formulae. The results obtained showed that spatial variation was insignificant, in terms of the temperature and humidity variables. The annual mean temperature (Tmean) ranged between 21.9 and 30.4 degrees C while minimum (Tmin) and maximum (Tmax) temperatures varied from 13 to 26 and 21.5-39.6 degrees C, respectively. Relative humidity (RH), actual vapour pressure (Es) and dew point temperature (Td) values also varied from 39.1% to 98.2%, 19.7-20.8 gm(-3), and 17.3-17.8 degrees C, respectively. A significant relationship (p>0.6; r<0.05) between Tmin, Es and Td was observed while the daytime 'urban heat island' intensity (UHI) ranged between 0.5 and 2.5 degrees C within the study period. The study concluded that there is influence of urban canopy on the microclimate of Akure, and hypothesizes that the urban dwellers may be subjected to some levels of weather related physiological disorderliness.

Wireless Sensor Network-Based Greenhouse Environment Monitoring and Automatic Control System for Dew Condensation Prevention

PubMed Central

Park, Dae-Heon; Park, Jang-Woo

2011-01-01

Dew condensation on the leaf surface of greenhouse crops can promote diseases caused by fungus and bacteria, affecting the growth of the crops. In this paper, we present a WSN (Wireless Sensor Network)-based automatic monitoring system to prevent dew condensation in a greenhouse environment. The system is composed of sensor nodes for collecting data, base nodes for processing collected data, relay nodes for driving devices for adjusting the environment inside greenhouse and an environment server for data storage and processing. Using the Barenbrug formula for calculating the dew point on the leaves, this system is realized to prevent dew condensation phenomena on the crop’s surface acting as an important element for prevention of diseases infections. We also constructed a physical model resembling the typical greenhouse in order to verify the performance of our system with regard to dew condensation control. PMID:22163813

Wireless sensor network-based greenhouse environment monitoring and automatic control system for dew condensation prevention.

PubMed

Park, Dae-Heon; Park, Jang-Woo

2011-01-01

Dew condensation on the leaf surface of greenhouse crops can promote diseases caused by fungus and bacteria, affecting the growth of the crops. In this paper, we present a WSN (Wireless Sensor Network)-based automatic monitoring system to prevent dew condensation in a greenhouse environment. The system is composed of sensor nodes for collecting data, base nodes for processing collected data, relay nodes for driving devices for adjusting the environment inside greenhouse and an environment server for data storage and processing. Using the Barenbrug formula for calculating the dew point on the leaves, this system is realized to prevent dew condensation phenomena on the crop's surface acting as an important element for prevention of diseases infections. We also constructed a physical model resembling the typical greenhouse in order to verify the performance of our system with regard to dew condensation control.

Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

NASA Astrophysics Data System (ADS)

Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

2018-05-01

Air cooling units (ACU) are used at all the gas fields for cooling natural gas after compressing. When using ACUs on raw (wet) gas in a low temperature condition, there is a danger of hydrate plug formation in the heat exchanging tubes of the ACU. To predict possible hydrate formation, a mathematical model of the air cooler thermal behavior used in the control system shall adequately calculate not only gas temperature at the cooler's outlet, but also a dew point value, a temperature at which condensation, as well as the gas hydrate formation point, onsets. This paper proposes a mathematical model allowing one to determine the pressure in the air cooler which makes hydrate formation for a given gas composition possible.

Infectious Disease in a Warming World: How Weather Influenced West Nile Virus in the United States (2001–2005)

PubMed Central

Soverow, Jonathan E.; Wellenius, Gregory A.; Fisman, David N.; Mittleman, Murray A.

2009-01-01

Background The effects of weather on West Nile virus (WNV) mosquito populations in the United States have been widely reported, but few studies assess their overall impact on transmission to humans. Objectives We investigated meteorologic conditions associated with reported human WNV cases in the United States. Methods We conducted a case–crossover study to assess 16,298 human WNV cases reported to the Centers for Disease Control and Prevention from 2001 to 2005. The primary outcome measures were the incidence rate ratio of disease occurrence associated with mean weekly maximum temperature, cumulative weekly temperature, mean weekly dew point temperature, cumulative weekly precipitation, and the presence of ≥ 1 day of heavy rainfall (≥ 50 mm) during the month prior to symptom onset. Results Increasing weekly maximum temperature and weekly cumulative temperature were similarly and significantly associated with a 35–83% higher incidence of reported WNV infection over the next month. An increase in mean weekly dew point temperature was significantly associated with a 9–38% higher incidence over the subsequent 3 weeks. The presence of at least 1 day of heavy rainfall within a week was associated with a 29–66% higher incidence during the same week and over the subsequent 2 weeks. A 20-mm increase in cumulative weekly precipitation was significantly associated with a 4–8% increase in incidence of reported WNV infection over the subsequent 2 weeks. Conclusions Warmer temperatures, elevated humidity, and heavy precipitation increased the rate of human WNV infection in the United States independent of season and each others’ effects. PMID:19654911

Forest fire danger index based on modifying Nesterov Index, fuel, and anthropogenic activities using MODIS TERRA, AQUA and TRMM satellite datasets

NASA Astrophysics Data System (ADS)

Suresh Babu, K. V.; Roy, Arijit; Ramachandra Prasad, P.

2016-05-01

Forest fire has been regarded as one of the major causes of degradation of Himalayan forests in Uttarakhand. Forest fires occur annually in more than 50% of forests in Uttarakhand state, mostly due to anthropogenic activities and spreads due to moisture conditions and type of forest fuels. Empirical drought indices such as Keetch-Byram drought index, the Nesterov index, Modified Nesterov index, the Zhdanko index which belongs to the cumulative type and the Angstrom Index which belongs to the daily type have been used throughout the world to assess the potential fire danger. In this study, the forest fire danger index has been developed from slightly modified Nesterov index, fuel and anthropogenic activities. Datasets such as MODIS TERRA Land Surface Temperature and emissivity (MOD11A1), MODIS AQUA Atmospheric profile product (MYD07) have been used to determine the dew point temperature and land surface temperature. Precipitation coefficient has been computed from Tropical Rainfall measuring Mission (TRMM) product (3B42RT). Nesterov index has been slightly modified according to the Indian context and computed using land surface temperature, dew point temperature and precipitation coefficient. Fuel type danger index has been derived from forest type map of ISRO based on historical fire location information and disturbance danger index has been derived from disturbance map of ISRO. Finally, forest fire danger index has been developed from the above mentioned indices and MODIS Thermal anomaly product (MOD14) has been used for validating the forest fire danger index.

Precipitation Field and Intrastorm Flow of Supercell Convective Storms.

DTIC Science & Technology

1981-08-01

1978: Observations of radome transmission losses at 5 cm wavelengths. Preprints 18th Conf. on Radar Meteor., Atlanta, Amer. Meteor. Soc., 288-291. , and...La, and Lr are loss factors (dimensionless) for the radome, the transmission path, and atmospheric gaseous absorp- tion. Typical values are Lc - 2dB...surface fields. Objectively analyzed maps of streamflow , wind com- ponents, temperature, dew point, pressure, divergence, vorticity, mix- ing ratio, and

Physical Processes in Coastal Stratocumulus Clouds from Aircraft Measurements During UPPEF 2012

DTIC Science & Technology

2013-09-01

pressure, dew point, water vapor, absolute humidity, and carbon dioxide concentration. There were various upward and downward looking pyranometers ...Meteorological parameters IR Temperature -50 to +20 °C Up-looking modified Kipp & Zonen CM-22 pyranometer (CIRPAS/NRL) Meteorological parameters Down...welling Solar Irradiance 0-1400 W m -2 Down-looking modified Kipp & Zonen CM-22 pyranometer (CIRPAS/NRL) Meteorological parameters Up-welling Solar

Inventory of File naefs_geavg.t12z.ndgd_conusf06.grib2

Science.gov Websites

Number of Records: 8 Number Level/Layer Parameter Forecast Valid Description 001 surface PRES 6 hour fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 6 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 6 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 6 hour fcst Dew Point

Inventory of File naefs_geavg.t12z.ndgd_alaskaf06.grib

Science.gov Websites

Number of Records: 8 Number Level/Layer Parameter Forecast Valid Description 001 surface PRES 6 hour fcst Pressure [Pa] ens-mean 002 2 m above ground TMP 6 hour fcst Temperature [K] ens-mean 003 2 m above ground RH 6 hour fcst Relative Humidity [%] ens-mean 004 2 m above ground DPT 6 hour fcst Dew Point

Correlation of spring spore concentrations and meteorological conditions in Tulsa, Oklahoma

NASA Astrophysics Data System (ADS)

Troutt, C.; Levetin, E.

Different spore types are abundant in the atmosphere depending on the weather conditions. Ascospores generally follow precipitation, while spore types such as Alternaria and Cladosporium are abundant in dry conditions. This project attempted to correlate fungal spore concentrations with meteorological data from Tulsa, Oklahoma during May 1998 and May 1999. Air samples were collected and analyzed by the 12-traverse method. The spore types included were Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, and other spores. Weather variables included precipitation levels, temperature, dew point, air pressure, wind speed, wind direction and wind gusts. There were over 242.57 mm of rainfall in May 1999 and only 64.01 mm in May 1998. The most abundant spore types during May 1998 and May 1999 were Cladosporium, ascospores, and basidiospores. Results showed that there were significant differences in the dry-air spora between May 1998 and May 1999. There were twice as many Cladosporium in May 1998 as in May 1999; both ascospores and basidiospores showed little change. Multiple regression analysis was used to determine which meteorological variables influenced spore concentrations. Results showed that there was no single model for all spore types. Different combinations of factors were predictors of concentration for the various fungi examined; however, temperature and dew point seemed to be the most important meteorological factors.

Effects of climatic variables on weight loss: a global analysis.

PubMed

Ustulin, Morena; Keum, Changwon; Woo, Junghoon; Woo, Jeong-Taek; Rhee, Sang Youl

2017-01-20

Several studies have analyzed the effects of weather on factors associated with weight loss. In this study, we directly analyzed the effect of weather on intentional weight loss using global-scale data provided by smartphone applications. Through Weather Underground API and the Noom Coach application, we extracted information on weather and body weight for each user located in each of several geographic areas on all login days. We identified meteorological information (pressure, precipitation, wind speed, dew point, and temperature) and self-monitored body weight data simultaneously. A linear mixed-effects model was performed analyzing 3274 subjects. Subjects in North America had higher initial BMIs than those of subjects in Eastern Asia. During the study period, most subjects who used the smartphone application experienced weight loss in a significant way (80.39%, p-value < 0.001). Subjects who infrequently recorded information about dinner had smaller variations than those of other subjects (β freq.users dinner*time  = 0.007, p-value < 0.001). Colder temperature, lower dew point, and higher values for wind speed and precipitation were significantly associated with weight loss. In conclusion, we found a direct and independent impact of meteorological conditions on intentional weight loss efforts on a global scale (not only on a local level).

Effects of climatic variables on weight loss: a global analysis

PubMed Central

Ustulin, Morena; Keum, Changwon; Woo, Junghoon; Woo, Jeong-taek; Rhee, Sang Youl

2017-01-01

Several studies have analyzed the effects of weather on factors associated with weight loss. In this study, we directly analyzed the effect of weather on intentional weight loss using global-scale data provided by smartphone applications. Through Weather Underground API and the Noom Coach application, we extracted information on weather and body weight for each user located in each of several geographic areas on all login days. We identified meteorological information (pressure, precipitation, wind speed, dew point, and temperature) and self-monitored body weight data simultaneously. A linear mixed-effects model was performed analyzing 3274 subjects. Subjects in North America had higher initial BMIs than those of subjects in Eastern Asia. During the study period, most subjects who used the smartphone application experienced weight loss in a significant way (80.39%, p-value < 0.001). Subjects who infrequently recorded information about dinner had smaller variations than those of other subjects (βfreq.users dinner*time = 0.007, p-value < 0.001). Colder temperature, lower dew point, and higher values for wind speed and precipitation were significantly associated with weight loss. In conclusion, we found a direct and independent impact of meteorological conditions on intentional weight loss efforts on a global scale (not only on a local level). PMID:28106167

A pilot study to investigate the effects of combined dehumidification and HEPA filtration on dew point and airborne mold spore counts in day care centers.

PubMed

Bernstein, J A; Levin, L; Crandall, M S; Perez, A; Lanphear, B

2005-12-01

Meteorological factors such as relative humidity directly correlate with airborne fungal levels outdoors and indoors. While dehumidification alone is effective at reducing moisture necessary for mold growth, it is inadequate as a single intervention as it does not remove viable and non-viable fungal spores that are potentially allergenic. The purpose of this pilot study was to investigate whether dehumidification in combination with high-efficiency particulate arrestance (HEPA) filtration is effective at reducing airborne mold spore levels in day care centers. Two day care centers within a 2-mile radius of each other were selected. Day care center A was 2 years old with eight rooms while day care center B was 15 years old with six rooms. A high efficiency Santa Fe dehumidification unit equipped with a HEPA filter was installed in half the rooms (intervention) of each day care facility. Electronic HOBO data loggers continuously measured outdoor and indoor room dew point and temperature every 2 h throughout the study. Dew point and airborne fungal spore measurements from selected rooms with controlled air conditions were analyzed by comparing baseline measurements to those obtained at subsequent time periods over 1 year. Regression models accounted for correlations between measurements in the same room over time. Intervention resulted in a lowered average dew point from baseline by 8.8 degrees C compared with a decrease of 7.1 degrees C in non-intervention rooms across all time periods in both facilities (P<0.001). Fungal analyses demonstrated lower baseline (P=0.06) and follow-up means in intervention rooms (P<0.05), however the change from baseline to end of follow-up differed between intervention and non-intervention rooms in the two facilities. Log transformation was applied to approximate normality of fungal measurements. Dehumidification with HEPA filtration was effective at controlling indoor dew point in both facilities and at reducing airborne culturable fungal spore levels in one of the two facilities. These preliminary results provide a scientific rationale for using this intervention in future studies designed to investigate the impact of indoor mold exposure on health outcomes. Poor indoor air quality is a recognized cause or contributing factor to health effects. Dampness and humidity have been linked to upper and lower respiratory symptoms in children and adults. This study indicates that reducing indoor relative humidity and airborne mold spore levels using high-efficiency dehumidification units equipped with HEPA filtration is feasible even in work facilities such as day care centers where traffic in and out of the building is difficult to regulate. Clinicians should emphasize to their patients the importance of dehumidification and HEPA filtration to improve indoor air quality in the home and workplace.

Estimation of dew yield from radiative condensers by means of an energy balance model

NASA Astrophysics Data System (ADS)

Maestre-Valero, J. F.; Ragab, R.; Martínez-Alvarez, V.; Baille, A.

2012-08-01

SummaryThis paper presents an energy balance modelling approach to predict the nightly water yield and the surface temperature (Tf) of two passive radiative dew condensers (RDCs) tilted 30° from horizontal. One was fitted with a white hydrophilic polyethylene foil recommended for dew harvest and the other with a black polyethylene foil widely used in horticulture. The model was validated in south-eastern Spain by comparing the simulation outputs with field measurements of Tf and dew yield. The results indicate that the model is robust and accurate in reproducing the behaviour of the two RDCs, especially in what refers to Tf, whose estimates were very close to the observations. The results were somewhat less precise for dew yield, with a larger scatter around the 1:1 relationship. A sensitivity analysis showed that the simulated dew yield was highly sensitive to changes in relative humidity and downward longwave radiation. The proposed approach provides a useful tool to water managers for quantifying the amount of dew that could be harvested as a valuable water resource in arid, semiarid and water stressed regions.

Urban dew and rain in Paris, France: Occurrence and physico-chemical characteristics

NASA Astrophysics Data System (ADS)

Beysens, D.; Mongruel, A.; Acker, K.

2017-06-01

This paper summarizes one year (April 2011 to March 2012) measurements on planar condensing surfaces of dew and rain events and related physico-chemical characteristics in the urban environment of Paris (city center). Yearly collected water was 3.48 mm for dew (63 events) and 593 mm for rain (146 events). The latter value compares well with rain data (547 mm and 107 events) collected within 12 km at Paris-Orly airport. An estimation of dew yield based on meteo data gives 2.35 mm and 74 events, to be compared with 17.11 mm and 196 events at Paris-Orly. These differences highlight the large reduction in dew events and dew yields in an urban area as compared to a close rural-like area. This reduction is not due to a sky view reduction but to heat island that increases air temperature and decreases relative humidity. Analysis of dew (34) and rain (77) samples were done concerning pH, electrical conductivity (EC), major anions and cations as well as selected trace metals and other minor ions. Mean pH values are found similar for both, dew (6.5) and rain (6.1), rain being slightly more acidic than dew. The mean dew total ionic content (TIC 1.8 meq/l) and EC value (124 μS/cm) are about four times that of rain (0.45 meq/l; 35 μS/cm), meaning that total dissolved solids in dew is nearly four times that in rain. Sulfate and nitrate are the most acidifying components, calcium the most neutralizing constituent with ratio of mean total acidity/total alkalinity comparable for dew and rain ( 0.9). Sulfate and nitrate have mainly anthropogenic sources, whereas chloride and magnesium are mostly connected with marine air masses. Dew is a considerable factor of wet deposition of pollutants; dew and rain ion concentrations, however, meet the WHO requirements for drinking water.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Confer, L.; Kramer, K.L.

A condensing type heat exchanger operating at Henkel Corporation's plant in Kankakee, IL, has enabled the plant to save $400,000 in energy costs within the first 22 months of operation, recouping the initial capital investment for the unit within that time frame. The heat exchanger enables the plant to accomplish what historically was considered taboo - to cool boiler stack gas down to 130/sup 0/F, below the dew point, and thus recover both sensible and latent heat from the gas. Traditionally, moisture could not be squeezed out of stack gas below the recommended temperature of 250/sup 0/F because the stackmore » gas close to the heat exchanger tubes would approach the dew point, condense and attack metal surfaces. The condensing type heat exchanger can withstand corrosive conditions, however, because all wetted surfaces on the flue side of the shell and copper-nickel tube design are protected with an extruded Teflon fluorocarbon resin covering (not coating). The waste heat recovery system was installed over a two-month period in 1985. Performance has been above expectations with greater energy savings than originally projected. The amount of operator attention required is minimal.« less

Solid State Humidity Sensors

NASA Astrophysics Data System (ADS)

Chang, Song-Lin

There are only a few solid state humidity sensors available today. Most of those sensors use a porous oxide material as a principal part of the device. The devices work on the basis of a change in resistance as the moisture in the air varies. In this experiment, two solid state humidity sensors have been developed for use under practical conditions. One is a Polymer Oxide Semiconductor device with a POLYOX film that absorbs the moisture from the air. The amount of water dipoles absorbed by the polymer is a function of relative humidity. This sensor can measure relative humidity from 20% to 90%. The other is a Dew Point sensor. The sensor is in contact with the upper surface of a miniature Peltier cooler. Water molecules deposited on the sensor surface cause the electrical current through the sensor to increase. The operator adjusts the temperature of the Peltier cooler until a saturated current through the sensor is reached. About one min. is required to measure low relative humidities. The Dew Point sensor can measure a range of relative humidities of 30% to 80%.

Outdoor temperature is associated with serum HDL and LDL.

PubMed

Halonen, Jaana I; Zanobetti, Antonella; Sparrow, David; Vokonas, Pantel S; Schwartz, Joel

2011-02-01

While exposures to high and low air temperatures are associated with cardiovascular mortality, the underlying mechanisms are poorly understood. The risk factors for cardiovascular disease include high levels of total cholesterol and low-density lipoprotein (LDL), and low levels of high-density lipoprotein (HDL). We investigated whether temperature was associated with changes in circulating lipid levels, and whether this might explain part of the association with increased cardiovascular events. The study cohort consisted of 478 men in the greater Boston area with a mean age of 74.2 years. They visited the clinic every 3-5 years between 1995 and 2008 for physical examination and to complete questionnaires. We excluded from analyses all men taking statin medication and all days with missing data, resulting in a total of 862 visits. Associations between three temperature variables (ambient, apparent, and dew point temperature) and serum lipid levels (total cholesterol, HDL, LDL, and triglycerides) were studied with linear mixed models that included possible confounders such as air pollution and a random intercept for each subject. We found that HDL decreased -1.76% (95% CI: from -3.17 to -0.32, lag 2 days), and -5.58% (95% CI: from -8.87 to -2.16, moving average of 4 weeks) for each 5°C increase in mean ambient temperature. For the same increase in mean ambient temperature, LDL increased by 1.74% (95% CI: 0.07-3.44, lag 1 day) and 1.87% (95% CI: 0.14-3.63, lag 2 days). These results were also similar for apparent and dew point temperatures. No changes were found in total cholesterol or triglycerides in relation to temperature increase. Changes in HDL and LDL levels associated with an increase in ambient temperature may be among the underlying mechanisms of temperature-related cardiovascular mortality. Copyright © 2010 Elsevier Inc. All rights reserved.

Analysis of the Dryden Wet Bulb GLobe Temperature Algorithm for White Sands Missile Range

NASA Technical Reports Server (NTRS)

LaQuay, Ryan Matthew

2011-01-01

In locations where workforce is exposed to high relative humidity and light winds, heat stress is a significant concern. Such is the case at the White Sands Missile Range in New Mexico. Heat stress is depicted by the wet bulb globe temperature, which is the official measurement used by the American Conference of Governmental Industrial Hygienists. The wet bulb globe temperature is measured by an instrument which was designed to be portable and needing routine maintenance. As an alternative form for measuring the wet bulb globe temperature, algorithms have been created to calculate the wet bulb globe temperature from basic meteorological observations. The algorithms are location dependent; therefore a specific algorithm is usually not suitable for multiple locations. Due to climatology similarities, the algorithm developed for use at the Dryden Flight Research Center was applied to data from the White Sands Missile Range. A study was performed that compared a wet bulb globe instrument to data from two Surface Atmospheric Measurement Systems that was applied to the Dryden wet bulb globe temperature algorithm. The period of study was from June to September of2009, with focus being applied from 0900 to 1800, local time. Analysis showed that the algorithm worked well, with a few exceptions. The algorithm becomes less accurate to the measurement when the dew point temperature is over 10 Celsius. Cloud cover also has a significant effect on the measured wet bulb globe temperature. The algorithm does not show red and black heat stress flags well due to shorter time scales of such events. The results of this study show that it is plausible that the Dryden Flight Research wet bulb globe temperature algorithm is compatible with the White Sands Missile Range, except for when there are increased dew point temperatures and cloud cover or precipitation. During such occasions, the wet bulb globe temperature instrument would be the preferred method of measurement. Out of the 30 dates examined, 23 fell under the category of having good accuracy.

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

NASA Astrophysics Data System (ADS)

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).

Atmospheric Pressure and Onset of Episodes of Menière's Disease - A Repeated Measures Study.

PubMed

Gürkov, Robert; Strobl, Ralf; Heinlin, Nina; Krause, Eike; Olzowy, Bernhard; Koppe, Christina; Grill, Eva

2016-01-01

External changes of air pressure are transmitted to the middle and inner ear and may be used therapeutically in Menière's disease, one of the most common vertigo disorders. We analyzed the possible relationship of atmospheric pressure and other meteorological parameters with the onset of MD vertigo episodes in order to determine whether atmospheric pressure changes play a role in the occurrence of MD episodes. Patients of a tertiary outpatient dizziness clinic diagnosed with MD were asked to keep a daily vertigo diary to document MD episodes (2004-2009). Local air pressure, absolute temperature and dew point temperature were acquired on an hourly basis. Change in meteorological parameters was conceptualized as the maximum difference in a 24 hour time frame preceding each day. Effects were estimated using additive mixed models with a random participant effect. We included lagged air parameters, age, sex, weekday and season in the model. A total of 56 persons (59% female) with mean age 54 years were included. Mean follow-up time was 267 days. Persons experienced on average 10.3 episodes during the observation period (median 8). Age and change in air pressure were significantly associated with vertigo onset risk (Odds Ratio = 0.979 and 1.010). We could not show an effect of sex, weekday, season, air temperature, and dew point temperature. Change in air pressure was significantly associated with onset of MD episodes, suggesting a potential triggering mechanism in the inner ear. MD patients may possibly use air pressure changes as an early warning system for vertigo attacks in the future.

Maisotsenko cycle applications for multistage compressors cooling

NASA Astrophysics Data System (ADS)

Levchenko, D.; Yurko, I.; Artyukhov, A.; Baga, V.

2017-08-01

The present study provides the overview of Maisotsenko Cycle (M-Cycle) applications for gas cooling in compressor systems. Various schemes of gas cooling systems are considered regarding to their thermal efficiency and cooling capacity. Preliminary calculation of M-cycle HMX has been conducted. It is found that M-cycle HMX scheme allows to brake the limit of the ambient wet bulb temperature for evaporative cooling. It has demonstrated that a compact integrated heat and moisture exchange process can cool product fluid to the level below the ambient wet bulb temperature, even to the level of dew point temperature of the incoming air with substantially lower water and energy consumption requirements.

The Viability of a Metamaterial Solution for the Defense of an Incident High-Energy Electromagnetic Beam

DTIC Science & Technology

2010-12-01

INTRODUCTION ............................................1 A. DIRECTED ENERGY WEAPONS ( DEW ) ......................1 B. FREE ELECTRON LASER (FEL...WEAPONS (C- DEW ) ............7 1. Navy Relevance ................................7 2. Problem Description ...........................7 II...invisibility cloaks from [9].................................18 Figure 7. Simple cubic lattice of points in co-coordinate system (left) maps into a

Surface and Tower Meteorological Instrumentation at NSA Handbook - January 2006

DOE Office of Scientific and Technical Information (OSTI.GOV)

MT Ritsche

2006-01-30

The Surface and Tower Meteorological Instrumentation at Atqasuk (METTWR2H) uses mainly conventional in situ sensors to measure wind speed, wind direction, air temperature, dew point and humidity mounted on a 10-m tower. It also obtains barometric pressure, visibility, and precipitation data from sensors at or near the base of the tower. In addition, a Chilled Mirror Hygrometer is located at 1 m for comparison purposes. Temperature and relative humidity probes are mounted at 2 m and 5 m on the tower. For more information, see the Surface and Tower Meteorological Instrumentation at Atqasuk Handbook.

Satellite freeze forecast system

NASA Technical Reports Server (NTRS)

Martsolf, J. D. (Principal Investigator)

1983-01-01

Provisions for back-up operations for the satellite freeze forecast system are discussed including software and hardware maintenance and DS/1000-1V linkage; troubleshooting; and digitized radar usage. The documentation developed; dissemination of data products via television and the IFAS computer network; data base management; predictive models; the installation of and progress towards the operational status of key stations; and digital data acquisition are also considered. The d addition of dew point temperature into the P-model is outlined.

Comparative verification between GEM model and official aviation terminal forecasts

NASA Technical Reports Server (NTRS)

Miller, Robert G.

1988-01-01

The Generalized Exponential Markov (GEM) model uses the local standard airways observation (SAO) to predict hour-by-hour the following elements: temperature, pressure, dew point depression, first and second cloud-layer height and amount, ceiling, total cloud amount, visibility, wind, and present weather conditions. GEM is superior to persistence at all projections for all elements in a large independent sample. A minute-by-minute GEM forecasting system utilizing the Automated Weather Observation System (AWOS) is under development.

Radiation forcing by the atmospheric aerosols in the nocturnal boundary layer

NASA Astrophysics Data System (ADS)

Singh, D. K.; Ponnulakshami, V. K.; Mukund, V.; Subramanian, G.; Sreenivas, K. R.

2013-05-01

We have conducted experimental and theoretical studies on the radiation forcing due to suspended aerosols in the nocturnal boundary layer. We present radiative, conductive and convective equilibrium profile for different bottom boundaries where calculated Rayleigh number is higher than the critical Rayleigh number in laboratory conditions. The temperature profile can be fitted using an exponential distribution of aerosols concentration field. We also present the vertical temperature profiles in a nocturnal boundary in the presence of fog in the field. Our results show that during the presence of fog in the atmosphere, the ground temperature is greater than the dew-point temperature. The temperature profiles before and after the formation of fog are also observed to be different.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

PubMed Central

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-01-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions. PMID:25199907

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye

NASA Astrophysics Data System (ADS)

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-01

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Dew inspired breathing-based detection of genetic point mutation visualized by naked eye.

PubMed

Xie, Liping; Wang, Tongzhou; Huang, Tianqi; Hou, Wei; Huang, Guoliang; Du, Yanan

2014-09-09

A novel label-free method based on breathing-induced vapor condensation was developed for detection of genetic point mutation. The dew-inspired detection was realized by integration of target-induced DNA ligation with rolling circle amplification (RCA). The vapor condensation induced by breathing transduced the RCA-amplified variances in DNA contents into visible contrast. The image could be recorded by a cell phone for further or even remote analysis. This green assay offers a naked-eye-reading method potentially applied for point-of-care liver cancer diagnosis in resource-limited regions.

Effects of sand burial on dew deposition on moss soil crust in a revegetated area of the Tennger Desert, Northern China

NASA Astrophysics Data System (ADS)

Jia, Rong-liang; Li, Xin-rong; Liu, Li-chao; Pan, Yan-xia; Gao, Yan-hong; Wei, Yong-ping

2014-11-01

Sand burial and dew deposition are two fundamental phenomena profoundly influencing biological soil crusts in desert areas. However, little information is available regarding the effects of sand burial on dew deposition on biological soil crusts in desert ecosystems. In this study, we evaluated the effects of sand burial at depths of 0 (control), 0.5, 1, 2 and 4 mm on dew formation and evaporation of three dominant moss crusts in a revegetated area of the Tengger Desert (Northern China) in 2010. The results revealed that sand burial significantly decreased the amount of dew deposited on the three moss crust types by acting as a semi-insulator retarding the dew formation and evaporation rates. The changes in surface temperature cannot fully explain the variations of the formation and evaporation rates of dew by moss crusts buried by sand. The extension of dew retention time was reflected by the higher dew ratios (the ratio of dew amount at a certain time to the maximum value in a daily course) in the daytime, and may to some extent have acted as compensatory mechanisms that diminished the negative effects of the reduction of dew amount induced by sand burial of moss crusts. The resistances to reduction of dewfall caused by sand burial among the three moss crusts were also compared and it was found that Bryum argenteum crust showed the highest tolerance, followed by crusts dominated by Didymodon vinealis and Syntrichia caninervis. This sequence corresponds well with the successional order of the three moss crusts in the revegetated area, thereby suggesting that resistance to reduction of dewfall may act as one mechanism by which sand burial drives the succession of moss crusts in desert ecosystems. This side effect of dew reduction induced by sand burial on biological soil crusts should be considered in future ecosystem construction and management of desert area.

Selective oxidation of dual phase steel after annealing at different dew points

NASA Astrophysics Data System (ADS)

Lins, Vanessa de Freitas Cunha; Madeira, Laureanny; Vilela, Jose Mario Carneiro; Andrade, Margareth Spangler; Buono, Vicente Tadeu Lopes; Guimarães, Juliana Porto; Alvarenga, Evandro de Azevedo

2011-04-01

Hot galvanized steels have been extensively used in the automotive industry. Selective oxidation on the steel surface affects the wettability of zinc on steel and the grain orientation of inhibition layer (Fe-Al-Zn alloy) and reduces the iron diffusion to the zinc layer. The aim of this work is to identify and quantify selective oxidation on the surface of a dual phase steel, and an experimental steel with a lower content of manganese, annealed at different dew points. The techniques employed were atomic force microscopy, X-ray photoelectron spectroscopy, and glow discharge optical emission spectroscopy. External selective oxidation was observed for phosphorus on steel surface annealed at 0 °C dp, and for manganese, silicon, and aluminum at a lower dew point. The concentration of manganese was higher on the dual phase steel surface than on the surface of the experimental steel. The concentration of molybdenum on the surface of both steels increased as the depth increased.

Effects of leaf hair points of a desert moss on water retention and dew formation: implications for desiccation tolerance.

PubMed

Tao, Ye; Zhang, Yuan Ming

2012-05-01

Leaf hair points (LHPs) are important morphological structures in many desiccation-tolerant mosses, but study of their functions has been limited. A desert moss, Syntrichia caninervis, was chosen for examination of the ecological effects of LHPs on water retention and dew formation at individual and population (patch) levels. Although LHPs were only 4.77% of shoot weight, they were able to increase absolute water content (AWC) by 24.87%. The AWC of samples with LHPs was always greater than for those without LHPs during dehydration. The accumulative evaporation ratio (AER) showed an opposite trend. AWC, evaporation ratio and AER of shoots with LHPs took 20 min longer to reach a completely dehydrated state than shoots without LHPs. At the population level, dew formation on moss crusts with LHPs was faster than on crusts without LHPs, and the former had higher daily and total dew amounts. LHPs were able to improve dew amounts on crusts by 10.26%. Following three simulated rainfall events (1, 3 and 6 mm), AERs from crusts with LHPs were always lower than from crusts without LHPs. LHPs can therefore significantly delay and reduce evaporation. We confirm that LHPs are important desiccation-tolerant features of S. caninervis at both individual and population levels. LHPs greatly aid moss crusts in adapting to arid conditions.

Evaluating the effects of historical land cover change on summertime weather and climate in New Jersey: Land cover and surface energy budget changes

USGS Publications Warehouse

Wichansky, P.S.; Steyaert, L.T.; Walko, R.L.; Waever, C.P.

2008-01-01

The 19th-century agrarian landscape of New Jersey (NJ) and the surrounding region has been extensively transformed to the present-day land cover by urbanization, reforestation, and localized areas of deforestation. This study used a mesoscale atmospheric numerical model to investigate the sensitivity of the warm season climate of NJ to these land cover changes. Reconstructed 1880s-era and present-day land cover data sets were used as surface boundary conditions for a set of simulations performed with the Regional Atmospheric Modeling System (RAMS). Three-member ensembles with historical and present-day land cover were compared to examine the sensitivity of surface air and dew point temperatures, rainfall, and the individual components of the surface energy budget to these land cover changes. Mean temperatures for the present-day landscape were 0.3-0.6??C warmer than for the historical landscape over a considerable portion of NJ and the surrounding region, with daily maximum temperatures at least 1.0??C warmer over some of the highly urbanized locations. Reforested regions, however, were slightly cooler. Dew point temperatures decreased by 0.3-0.6??C, suggesting drier, less humid near-surface air for the present-day landscape. Surface warming was generally associated with repartitioning of net radiation from latent to sensible heat flux, and conversely for cooling. While urbanization was accompanied by strong surface albedo decreases and increases in net shortwave radiation, reforestation and potential changes in forest composition have generally increased albedos and also enhanced landscape heterogeneity. The increased deciduousness of forests may have further reduced net downward longwave radiation. Copyright 2008 by the American Geophysical Union.

Atmospheric Pressure and Onset of Episodes of Menière’s Disease - A Repeated Measures Study

PubMed Central

Strobl, Ralf; Heinlin, Nina; Krause, Eike; Olzowy, Bernhard; Koppe, Christina; Grill, Eva

2016-01-01

Background External changes of air pressure are transmitted to the middle and inner ear and may be used therapeutically in Menière’s disease, one of the most common vertigo disorders. We analyzed the possible relationship of atmospheric pressure and other meteorological parameters with the onset of MD vertigo episodes in order to determine whether atmospheric pressure changes play a role in the occurrence of MD episodes. Methods Patients of a tertiary outpatient dizziness clinic diagnosed with MD were asked to keep a daily vertigo diary to document MD episodes (2004–2009). Local air pressure, absolute temperature and dew point temperature were acquired on an hourly basis. Change in meteorological parameters was conceptualized as the maximum difference in a 24 hour time frame preceding each day. Effects were estimated using additive mixed models with a random participant effect. We included lagged air parameters, age, sex, weekday and season in the model. Results A total of 56 persons (59% female) with mean age 54 years were included. Mean follow-up time was 267 days. Persons experienced on average 10.3 episodes during the observation period (median 8). Age and change in air pressure were significantly associated with vertigo onset risk (Odds Ratio = 0.979 and 1.010). We could not show an effect of sex, weekday, season, air temperature, and dew point temperature. Conclusions Change in air pressure was significantly associated with onset of MD episodes, suggesting a potential triggering mechanism in the inner ear. MD patients may possibly use air pressure changes as an early warning system for vertigo attacks in the future. PMID:27096752

A gas sampling system for withdrawing humid gases from deep boreholes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rousseau, J.P.; Thordarson, W.; Kurzmack, M.A.

A gas sampling system, designed to withdraw nearly vapor-saturated gases (93 to 100% relative humidity) from deep, unsaturated zone boreholes, was developed by the U.S. Geological Survey for use in the unsaturated zone borehole instrumentation and monitoring program at Yucca Mountain, Nye County, Nevada. This gas sampling system will be used to: (1) sample formation rock gases in support of the unsaturated zone hydrochemical characterization program; and (2) verify downhole, thermocouple psychrometer measurements of water potential in support of the unsaturated zone borehole instrumentation and monitoring program. Using this sampling system, nearly vapor-saturated formation rock-gases can be withdrawn from deepmore » boreholes without condensing water vapor in the sampling tubes, and fractionating heavy isotopes of oxygen, hydrogen, and carbon. The sampling system described in this paper uses a dry carrier-gas (nitrogen) to lower the dew point temperature of the formation rock-gas at its source. Mixing of the dry carrier gas with the source gas takes place inside a specially designed downhole instrument station apparatus (DISA). Nitrogen inflow is regulated in a manner that lowers the dew point temperature of the source gas to a temperature that is colder than the coldest temperature that the mixed gas will experience in moving from warmer, deeper depths, to colder, shallower depths near the land surface. A test of this gas sampling system was conducted in December, 1992, in a 12.2 meter deep borehole that was instrumented in October, 1991. The water potential calculated using this system reproduced in-situ measurements of water potential to within five percent of the average value, as recorded by two thermocouple psychrometers that had been in operation for over 12 months.« less

BOREAS AES Campbell Scientific Surface Meteorological Data

NASA Technical Reports Server (NTRS)

Atkinson, G. Barrie; Funk, Barrie; Knapp. David E. (Editor); Hall, Forrest G. (Editor)

2000-01-01

Canadian AES personnel collected data related to surface and atmospheric meteorological conditions over the BOREAS region. This data set contains 15-minute meteorological data from 14 automated meteorology stations located across the BOREAS region. Included in this data are parameters of date, time, mean sea level pressure, station pressure, temperature, dew point, wind speed, resultant wind speed, resultant wind direction, peak wind, precipitation, maximum temperature in the last hour, minimum temperature in the last hour, pressure tendency, liquid precipitation in the last hour, relative humidity, precipitation from a weighing gauge, and snow depth. Temporally, the data cover the period of August 1993 to December 1996. The data are provided in tabular ASCII files, and are classified as AFM-Staff data.

Investigation of Changes in Extreme Temperature and Humidity Over China Through a Dynamical Downscaling Approach

NASA Astrophysics Data System (ADS)

Zhu, Jinxin; Huang, Gordon; Wang, Xiuquan; Cheng, Guanhui

2017-11-01

Impacts of climate change relating to public health are often determined by multiple climate variables. The health-related metrics combining high-temperature and relative humidity are most concerned. Temperatures, relative humidity and relationship among them are investigated here for a comprehensive assessment of climate change impacts over China. A projection of combined temperatures and humidity through the PRECIS model is addressed. The PRECIS model's skill in reproducing the historical climate over China was first gauged through validating its historical simulation with the observation data set in terms of the two contributing variables. With good results of validation, a plausible range of combined temperatures and relative humidity were generated under RCPs. The results suggested that the annual mean temperature of China will increase up to 6°C at the end of 21st century. Opposite to the significantly change in the temperature, the maximum magnitude of changes in relative humidity is only 8% from the value in the baseline period. The dew point temperature is projected to be 14.9°C (within the comfortable interval) over the whole nation under high radiative forcing scenario at the end of this century. Therefore, the combination effects of high temperatures and relative humidity are substantially smaller than generally anticipated for China. Even though the impact-relevant metric like the dew point temperature is not projected as bad as the generally anticipated, we found that the frequency of high-temperature extremes increases up to 40% and the duration increases up to 150% in China. China is still expected to have more number of extremely hot days, more frequent high-temperature extremes, and longer duration of warm spell than before. Regionally, South China has the smallest changes in the mean, maximum and minimum temperatures while the largest increases in all five high-temperature indices. Consequently, the climate over South China for two future periods will be changing more drastically than the baseline period. Extra cautions need to be given to South China in the future.

Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.

PubMed

Dozier, W A; Lott, B D; Branton, S L

2005-08-01

This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.

Meteorological conditions are associated with physical activities performed in open-air settings

NASA Astrophysics Data System (ADS)

Suminski, Richard R.; Poston, Walker C.; Market, Patrick; Hyder, Melissa; Sara, Pyle A.

2008-01-01

Meteorological conditions (MC) are believed to modify physical activity. However, studies in this area are limited and none have looked at the associations between MC and physical activity in open-air settings. Therefore, we examined the relationships between MC and physical activities performed on sidewalks/streets and outdoor oval tracks. Observation techniques were used to count individuals walking to school, exercising on oval tracks and walking/jogging/biking on sidewalks/streets. Meteorological conditions were obtained from an Automated Surface Observing System located at a nearby airport for the same time periods physical activities were observed. On weekdays, fewer children were seen walking to school and more bicyclists were observed on sidewalks/streets as wind speed increased ( p < 0.05). Ambient and apparent temperatures were positively ( p < 0.05) and humidity and barometric pressure negatively ( p < 0.005) related to the number of individuals walking on the track. Meteorological conditions were not significantly associated with physical activities observed on weekends. Multiple linear regression analyses showed that apparent temperature (+), barometric pressure (-) and dew point (-) accounted for 58.0% of the variance in the number of walkers on the track. A significant proportion of the variance (>30%) in the number of joggers and the length of time they jogged was accounted for by apparent temperature (+) and dew point (-). We found that meteorological conditions are related to physical activity in open-air settings. The results embellish the context in which environmental-physical activity relationships should be interpreted and provide important information for researchers applying the observation method in open-air settings.

Correction of Thermal Gradient Errors in Stem Thermocouple Hygrometers

PubMed Central

Michel, Burlyn E.

1979-01-01

Stem thermocouple hygrometers were subjected to transient and stable thermal gradients while in contact with reference solutions of NaCl. Both dew point and psychrometric voltages were directly related to zero offset voltages, the latter reflecting the size of the thermal gradient. Although slopes were affected by absolute temperature, they were not affected by water potential. One hygrometer required a correction of 1.75 bars water potential per microvolt of zero offset, a value that was constant from 20 to 30 C. PMID:16660685

Investigation of JP-8 Autoignition Under Vitiated Combustion Conditions

DTIC Science & Technology

2011-01-01

no less than 1.5 times the dew point temperature of the mixture for all test cases that involved H2O. The flow path and apparatus for the steam...Variable m Interaction Effect of Design Variables m and n R Universal Gas Constant [cal/mol-K] E Activation Energy of Ignition Process [cal/mol] T...combustion including CO2, CO, H2O, and NOX. Vitiated conditions are often the result of flue or exhaust gas recirculation (EGR) into a fresh air stream

Air Sample Conditioner Helps the Waste Treatment Plant Meet Emissions Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glissmeyer, John A.; Flaherty, Julia E.; Pekour, Mikhail S.

2014-12-02

The air in three of the Hanford Site Waste Treatment and Immobilization Plant (WTP) melter off-gas discharge stacks will be hot and humid after passing through the train of emission abatement equipment. The off-gas temperature and humidity levels will be incompatible with the airborne emissions monitoring equipment required for this type of stack. To facilitate sampling from these facilities, an air sample conditioner system will be installed to introduce cool, dry air into the sample stream to reduce the temperature and dew point. This will avoid thermal damage to the instrumentation and problematic condensation. The complete sample transport system mustmore » also deliver at least 50% of the particles in the sample airstream to the sample collection and on-line analysis equipment. The primary components of the sample conditioning system were tested in a laboratory setting. The sample conditioner itself is based on a commercially-available porous tube filter design. It consists of a porous sintered metal tube inside a coaxial metal jacket. The hot gas sample stream passes axially through the porous tube, and the dry, cool air is injected into the jacket and through the porous wall of the inner tube, creating an effective sample diluter. The dilution and sample air mix along the entire length of the porous tube, thereby simultaneously reducing the dew point and temperature of the mixed sample stream. Furthermore, because the dilution air enters through the porous tube wall, the sample stream does not come in contact with the porous wall and particle deposition is reduced in this part of the sampling system. Tests were performed with an environmental chamber to supply air with the temperature and humidity needed to simulate the off-gas conditions. Air from the chamber was passed through the conditioning system to test its ability to reduce the temperature and dew point of the sample stream. To measure particle deposition, oil droplets in the range of 9 to 11 micrometer aerodynamic diameter were injected into the environmental chamber and drawn through the conditioning system, which included a filter to capture droplets that passed through the conditioner. The droplets were tagged with a fluorescent dye which allowed quantification of droplet deposition on each component of the system. The tests demonstrated the required reductions in temperature and moisture, with no condensation forming when heat tracing was added on the upstream end of the sample conditioner. Additionally, tests indicated that the system, operating at several flow rates and in both vertical and horizontal orientations, delivers nearly all of the sampled particles for analysis. Typical aerosol penetration values were between 98 and 99%. PNNL, Bechtel National Inc., and the instrument vendor are working to implement the sample conditioner into the air monitoring systems used for the melter off-gas exhaust streams. Similar technology may be useful for processes in other facilities with air exhaust streams with elevated temperature and/or humidity.« less

The effect of substrate properties, size, position, sheltering and shading on dew: An experimental approach in the Negev Desert

NASA Astrophysics Data System (ADS)

Kidron, Giora J.

2010-11-01

Affected by the interrelationships between the air mass and the substrate properties, dew measurements entail numerous difficulties. Inattentiveness to the complexities involved may result in inconsistent and consequently unreliable data and thus in misleading conclusions. This is especially important in dew deserts such as the Negev where dew may be regarded as an important water source. In an attempt to highlight some of the factors that may affect dew condensation, an experimental approach was adapted during which dew condensation at different surfaces (smooth and ragged Plexiglas, bright limestone and dark flint cobbles), at various size substrata with identical axes (of 2.5, 5, 10, 20, 30 and 40 cm) or different size axes (of 10 × 20, 10 × 30 and 10 × 40 cm), and substrata at different heights and settings was measured. Some of the settings explored were also sheltered by a shrub, a cave, an 80-cm-tall cliff and neighboring cobbles. No significant differences were found in the dew amounts condensing on the limestone and the flint cobbles. Smooth Plexiglas surfaces yielded significantly higher amounts than a ragged Plexiglas surface. As for the substratum height and size, the dew amounts increased with height (from 0.7 to 10.0 cm) and size (from 2.5 × 2.5 cm to 40 × 40 cm). However, an increase in the long axis (a-axis) to 20, 30 and 40 cm while leaving the b-axis constant (at 10 cm) resulted in only a slight increase in the dew amounts in comparison to a 10 × 10 cm substratum. While confined to non-sheltered habitats, dew at partially sheltered habitats (such as the margin of a shrub or a cave, the vicinity of a cliff and on 7-cm-high cobble surrounded by 15-cm-high cobbles) was significantly lower than at the exposed habitats. The differences in dew amounts coincided with minute differences in the surface temperatures, explained as resulting from differences in the outgoing nocturnal longwave radiational cooling. The findings may shed light on the dew regime of lithobionts at different microhabitats and upon inconsistent values reported in the literature.

Wet-bulb, dew point, and air temperature trends in Spain

NASA Astrophysics Data System (ADS)

Moratiel, R.; Soriano, B.; Centeno, A.; Spano, D.; Snyder, R. L.

2017-10-01

This study analyses trends of mean ( T m), maximum ( T x), minimum ( T n), dew point ( T d), and wet-bulb temperatures ( T w) on an annual, seasonal, and monthly time scale over Spain during the period 1981-2010. The main purpose was to determine how temperature and humidity changes are impacting on T w, which is probably a better measure of climate change than temperature alone. In this study, 43 weather stations were used to detect data trends using the nonparametric Mann-Kendall test and the Sen method to estimate the slope of trends. Significant linear trends observed for T m, T x, and T n versus year were 56, 58, and 47 % of the weather stations, respectively, with temperature ranges between 0.2 and 0.4 °C per decade. The months with bigger trends were April, May, June, and July with the highest trend for T x. The spatial behaviour of T d and T w was variable, with various locations showing trends from -0.6 to +0.3 °C per decade for T d and from -0.4 to +0.5 °C per decade for T w. Both T d and T w showed negative trends for July, August, September, November, and December. Comparing the trends versus time of each variable versus each of the other variables exhibited poor relationships, which means you cannot predict the trend of one variable from the trend of another variable. The trend of T x was not related to the trend of T n. The trends of T x, T m, and T n versus time were unrelated to the trends versus time of either T d or T w. The trend of T w showed a high coefficient of determination with the trend of T d with an annual value of R 2 = 0.86. Therefore, the T w trend is more related to changes in humidity than temperature.

Selective Oxidation of a 0.1C-6Mn-2Si Third Generation Advanced High-Strength Steel During Dew-Point Controlled Annealing

NASA Astrophysics Data System (ADS)

Pourmajidian, Maedeh; McDermid, Joseph R.

2018-03-01

The present study investigates the selective oxidation of a 0.1C-6Mn-2Si medium-Mn advanced high-strength steel during austenization annealing heat treatments as a function of process atmosphere oxygen partial pressure and annealing time. It was determined that the surface oxide growth kinetics followed a parabolic rate law with the minimum rate belonging to the lowest oxygen partial pressure atmosphere at a dew point of 223 K (- 50 °C). The chemistry of the surface and subsurface oxides was studied using STEM + EELS on the sample cross sections, and it was found that the surface oxides formed under the 223 K (- 50 °C) dew-point atmosphere consisted of a layered configuration of SiO2, MnSiO3, and MnO, while in the case of the higher pO2 process atmospheres, only MnO was detected at the surface. Consistent with the Wagner calculations, it was shown that the transition to internal oxidation for Mn occurred under the 243 K (- 30 °C) and 278 K (+ 5 °C) dew-point atmospheres. However, the predictions of the external to internal oxidation for Si using the Wagner model did not correlate well with the experimental findings nor did the predictions of the Mataigne et al. model for multi-element alloys. Investigations of the internal oxide network at the grain boundaries revealed a multilayer oxide structure composed of amorphous SiO2 and crystalline MnSiO3, respectively, at the oxide core and outer shell. A mechanism for the formation of the oxide morphologies observed, based on kinetic and thermodynamic factors, was proposed. It is expected that only the fine and nodule-like MnO oxides formed on the surface of the samples annealed under the 278 K (+ 5 °C) dew-point process atmosphere for 60 and 120 seconds are sufficiently thin and of the desired dispersed morphology to promote reactive wetting by the molten galvanizing bath.

Nighttime water absorption by a bare loess soil in a coastal desert

NASA Astrophysics Data System (ADS)

Ninari, N.; Berliner, P. R.

2003-04-01

The role of dew in arid and semi-arid ecosystems is considered to be of great importance. It can serve as a water source for the bacteria of biological crust, for plants and for small insects. The Negev Desert is a semiarid region characterized by winter rainfall with a very large inter-annual variability. Reports on measurements carried out in this area mention that up to 180 nights a year with dew were registered by a conventional Hiltner Dew Balance, with intensities that ranged from 0.1 to 0.2 mm per night (yielding a total of 15 mm per year, which is more than 10% of the total rainfall). The Hiltner dew balance is based on the continuous weighing of an artificial condensation plate that has a completely different energy balance from that of the soil surface above which it is installed. The Hiltner dew balance could, therefore, be considered as a ``potential dew" gauge, whose results are probably mainly correlated to atmospheric conditions. The prime objective of this work was, therefore, to quantify the amounts of dew deposition on the soil surface, and to compare these amounts to those measured by the Hiltner balance. Measurements were carried out at the Wadi Mashash Experimental Farm in the Negev. To estimate deposition and evaporation of dew, a micro-lysimeter (diameter: 20 cm; soil depth: 50 cm) with an undisturbed soil sample was installed flush with the soil surface. The following were continuously monitored: micro-lysimeter weight, incoming and reflected short wave radiation, net radiation, dry and wet bulb temperatures, wind speed, and soil heat flux. A Hiltner Dew Balance was placed close by as a reference to compare with previous measurements. Throughout the ``dew period" (spring, summer and fall), and at random intervals, soil samples were taken hourly during the whole night. The uppermost 10 cm of the soil was divided into 1 cm intervals, and the soil moisture content was measured (oven dry). During the above-mentioned night campaigns, no dew deposition could be visually detected on the soil surface. A mass gain was however registered with the ML and an increase in moisture content was observed. The Hiltner balance clearly underestimated dew deposition amounts. These results indicate that although no visual signs of dew deposition could be detected, moisture did penetrate into the soil.

Meteorological influence on predicting surface SO2 concentration from satellite remote sensing in Shanghai, China.

PubMed

Xue, Dan; Yin, Jingyuan

2014-05-01

In this study, we explored the potential applications of the Ozone Monitoring Instrument (OMI) satellite sensor in air pollution research. The OMI planetary boundary layer sulfur dioxide (SO2_PBL) column density and daily average surface SO2 concentration of Shanghai from 2004 to 2012 were analyzed. After several consecutive years of increase, the surface SO2 concentration finally declined in 2007. It was higher in winter than in other seasons. The coefficient between daily average surface SO2 concentration and SO2_PBL was only 0.316. But SO2_PBL was found to be a highly significant predictor of the surface SO2 concentration using the simple regression model. Five meteorological factors were considered in this study, among them, temperature, dew point, relative humidity, and wind speed were negatively correlated with surface SO2 concentration, while pressure was positively correlated. Furthermore, it was found that dew point was a more effective predictor than temperature. When these meteorological factors were used in multiple regression, the determination coefficient reached 0.379. The relationship of the surface SO2 concentration and meteorological factors was seasonally dependent. In summer and autumn, the regression model performed better than in spring and winter. The surface SO2 concentration predicting method proposed in this study can be easily adapted for other regions, especially most useful for those having no operational air pollution forecasting services or having sparse ground monitoring networks.

Environmental dew point and skin and lip weathering.

PubMed

Devillers, C; Piérard, G E; Quatresooz, P; Piérard, S

2010-05-01

Xerosis represents a physiological response of the stratum corneum (SC) to environmental threats. The influence of the environmental dew point (DP) is not fully understood. This parameter is the air temperature at which the relative humidity is maximum. This study aimed to assess the relationship between the environmental DP and the water-holding capacity of the skin and lower lip vermilion. For comparison, SC property was evaluated after occlusive application of cooled and uncooled hydrogel pads. Electrometric measurements using a dermal phase meter (DPM) device were performed on the back of the hands, the cheeks and the lower lip of 40 healthy menopausal women. Assessments were performed in the outdoor conditions during winter and spring. The same measurements were recorded after hydrogel pads, at room temperature or cooled to 4 degrees C, were placed for 15 min on the test sites. The environmental DP was recorded at each evaluation time. The SC water-holding capacity was discretely influenced by the DP. In the open-air environmental conditions, a positive linear relationship was found on the cheeks between the DP and DPM values. The relationship was weaker on the lips. Conversely, a consistent increase in DPM values was recorded immediately after removal of the cooled and uncooled hydrogel pads. The observations made in the open-air testing conditions are consistent with the predicted events following the Arrhenius law. By contrast, the combination of cooling and occlusion by the hydrogel pads is responsible for the reverse effect on the SC.

Water potential in excised leaf tissue: comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley.

PubMed

Nelsen, C E; Safir, G R; Hanson, A D

1978-01-01

Leaf water potential (Psi(leaf)) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi(leaf) values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi(leaf) values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.

Closed Cycle Electric Discharge Laser Design Investigation

DTIC Science & Technology

1978-03-01

Report Number Assigned by Contract Monitor: NASA CR- 135408 Comments on Document: Archive, RRI, DEW Descriptors, Keywords: Closed Cycle Electric...Discharge Laser Design Investigation Carbon Dioxide Monoxide Space Airborne Heat Disposal Point Track Power Solar Generator Radiation Pages: 00100...Cataloged Date: Nov 27,1992 Contract Number: NAS 3-20100 Document Type: HC Number of Copies In Library: 000001 Record ID: 25219 Source of Document: DEW

Final report on EURAMET.T-K6.1: Bilateral comparison of the realisations of local dew/frost-point temperature scales in the range -70 °C to +20 °C

NASA Astrophysics Data System (ADS)

Heinonen, Martti; Zvizdic, Davor; Sestan, Danijel

2013-01-01

As the European extension of the first CCT humidity key comparison, EUROMET.T-K6 was successfully completed in year 2008. After this comparison, a new low dew-point generator was introduced at LPM in Croatia as a result of progress in the EUROMET P912 project. With this new facility, the LPM uncertainties decreased significantly and the operating range became significantly wider. Therefore, it was decided to arrange a bilateral comparison between LPM and MIKES in Finland providing a link to EUROMET.T-K6 and CCT-K6. This comparison was carried out in a manner similar to other K6 comparisons but only one transfer standard was used instead of two units and the measurement point -70 °C was added to the measurement scheme. At all measurement points, the bilateral equivalence was well within the estimated expanded uncertainty at the approximately 95% confidence level. Also, the deviations of the LPM results from the EUROMET.T-K6 reference values were smaller than their expanded uncertainties. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Analysis of the surface heat balance over the world ocean

NASA Technical Reports Server (NTRS)

Esbenson, S. K.

1981-01-01

The net surface heat fluxes over the global ocean for all calendar months were evaluated. To obtain a formula in the form Qs = Q2(T*A - Ts), where Qs is the net surface heat flux, Ts is the sea surface temperature, T*A is the apparent atmospheric equilibrium temperature, and Q2 is the proportionality constant. Here T*A and Q2, derived from the original heat flux formulas, are functions of the surface meteorological parameters (e.g., surface wind speed, air temperature, dew point, etc.) and the surface radiation parameters. This formulation of the net surface heat flux together with climatological atmospheric parameters provides a realistic and computationally efficient upper boundary condition for oceanic climate modeling.

Dew and hoarfrost frequency, formation efficiency and chemistry in Wroclaw, Poland

NASA Astrophysics Data System (ADS)

Gałek, G.; Sobik, M.; Błaś, M.; Polkowska, Ż.; Cichała-Kamrowska, K.; Wałaszek, K.

2015-01-01

This article presents the results of a research study concerning a comparison of frequency, formation efficiency and basic physico-chemical properties of dew and hoarfrost in urban conditions. Longer than two-year series of measurements was carried out from 1 February 2008 to 10 March 2010 in Wroclaw, Poland. Sampling of atmospheric deposits was made by means of insulated plain passive radiative condensers, which allowed to collect 222 dew and 96 hoarfrost samples. The results indicate that the frequency of dew days was about threefold greater than hoarfrost days. The formation efficiency of both types of deposits was almost the same, and reached a mean value of about 100 mL·m- 2 per day. The conducted analysis of several meteorological parameters showed that dew and hoarfrost, despite seasonal weather changes, were formed in very similar meteorological conditions. Only water vapor pressure values were in average twice higher in the case of dew and the impact of this parameter on dew and hoarfrost formation efficiency seems to be more complex than expected. The role of night duration in counterbalancing of smaller amount of available moisture in hoarfrost days is not clear. The investigation showed also, that there was an expected clear positive dependence of dew and hoarfrost formation efficiency on relative humidity, and not so evident in the case of temperature inversion, and wind velocity. The physico-chemical analysis indicated that the pH of dew was only slightly lower than the hoarfrost ones, regardless of the deposit formation intensity. Simultaneously, the lower pH values were much more frequent in the case of dew, which resulted from more effective absorption of anthropogenic NO3- and SO42 - ions. For both types of deposits, the average pH was low (4.5-4.8) in relation to majority of studies reported in literature. In spite of seasonal changes of pollutant concentration, various weather conditions and different mechanisms of pollutant absorption of dew and hoarfrost were characterized with almost identical, relatively low contamination - electric conductivity: 42 μS·cm- 1. The dominant ions were: Ca2 +, SO42 -, NO3-, as well as Cl- (hoarfrost only), all of them predominantly of anthropogenic origin.

Validation of snow line estimations using MODIS images for the Elqui River basin, Chile

NASA Astrophysics Data System (ADS)

Vasquez, Nicolas; Lagos, Miguel; Vargas, Ximena

2015-04-01

Precipitation events in North-Central Chile are very important because the region has a Mediterranean climate, with a humid period, and an extensive dry one. Separation between solid and liquid precipitation (snow line) in each event is important information that allow to estimate 1) the available snow covered area for snow-melt forecasting, during the dry season (the only resource of water in this period) and 2) the area affected by rain for flood modelling and infrastructure design. In this work, snow line was estimated with a meteorological approach, considering precipitation, temperature, relative humidity and dew point information at a daily scale from 2004 to 2010 and hourly from 2010 to 2013. In both periods, different meteorological stations are considered due to the implementation of new stations in the study area, covering from 1000 to 3000 (m.a.s.l) approximately, with snow and rain meteorological stations. The methodology exposed in this research is based in vertical variation of dew point and temperature due to more stability variations compared to vertical relative humidity behavior. The results calculated from meteorological data are compared with MODIS images, considering three criteria: (1) the median altitude of the minimum specific fractional snow covered area (FSCA), (2) the mean elevation of pixels with a FSCA<10% and (3) the snow line estimation via snow covered area and hypsometric curve. Historically in Chile, snow line has been studied considering few specific precipitation and temperature observations, or estimations of zero isotherms from upper air soundings. A comparison between these estimations and the results validated through MOD10A1/MYD10A1 products was made in order to identify tendencies and/or variations of the snow line at an annually scale.

Climatology of winter transition days for the contiguous USA, 1951-2007

NASA Astrophysics Data System (ADS)

Hondula, David M.; Davis, Robert E.

2011-01-01

In middle and high latitudes, climate change could impact the frequency and characteristics of frontal passages. Although transitions between air masses are significant features of the general circulation that influence human activities and other surface processes, they are much more difficult to objectively identify than single variables like temperature or even extreme events like fires, droughts, and floods. The recently developed Spatial Synoptic Classification (SSC) provides a fairly objective means of identifying frontal passages. In this research, we determine the specific meteorological patterns represented by the SSC's Transition category, a "catch-all" group that attempts to identify those days that cannot be characterized as a single, homogeneous air mass type. The result is a detailed transition climatology for the continental USA. We identify four subtypes of the Transition category based on intra-day sea level pressure change and dew point temperature change. Across the contiguous USA, most transition days are identified as cold fronts and warm fronts during the winter season. Among the two less common subtypes, transition days in which the dew point temperature and pressure both rise are more frequently observed across the western states, and days in which both variables fall are more frequently observed in coastal regions. The relative frequencies of wintertime warm and cold fronts have changed over the period 1951-2007. Relative cold front frequency has significantly increased in the Northeast and Midwest regions, and warm front frequencies have declined in the Midwest, Rocky Mountain, and Pacific Northwest regions. The overall shift toward cold fronts and away from warm fronts across the northern USA arises from a combination of an enhanced ridge over western North America and a northward shift of storm tracks throughout the mid-latitudes. These results are consistent with projections of climate change associated with elevated greenhouse gas concentrations.

New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, Ming; Abdelaziz, Omar; Yin, Hongxi

2014-11-01

Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150 200 C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50 60more » C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural gas boilers for applications with process fluid return temperatures higher than or close to the dew point of the water vapor in the flue gas.« less

Torrejon AB, Madrid, Spain. revised uniform summary of surface weather observations (RUSSWO). parts a-f. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1978-10-03

This report is a six-part statistical summary of surface weather observations for Torrejon AB, Madrid Spain. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in thismore » report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.« less

Method of immobilizing water-soluble bioorganic compounds on a capillary-porous carrier

DOEpatents

Ershov, Gennady Moiseevich; Timofeev, Eduard Nikolaevich; Ivanov, Igor Borisovich; Florentiev, Vladimir Leonidovich; Mirzabekov, Andrei Darievich

1998-01-01

The method for immobilizing water-soluble bioorganic compounds to capillary-porous carrier comprises application of solutions of water-soluble bioorganic compounds onto a capillary-porous carrier, setting the carrier temperature equal to or below the dew point of the ambient air, keeping the carrier till appearance of water condensate and complete swelling of the carrier, whereupon the carrier surface is coated with a layer of water-immiscible nonluminescent inert oil and is allowed to stand till completion of the chemical reaction of bonding the bioorganic compounds with the carrier.

Meteorological conditions during the summer 1986 CITE 2 flight series

NASA Technical Reports Server (NTRS)

Shipham, Mark C.; Cahoon, Donald R.; Bachmeier, A. Scott

1990-01-01

An overview of meteorological conditions during the NASA Global Tropospheric Experiment/Chemical Instrumentation Testing and Evaluation (GTE/CITE 2) summer 1986 flight series is presented. Computer-generated isentropic trajectories are used to trace the history of air masses encountered along each aircraft flight path. The synoptic-scale wind fields are depicted based on Montgomery stream function analyses. Time series of aircraft-measured temperature, dew point, ozone, and altitude are shown to depict air mass variability. Observed differences between maritime tropical and maritime polar air masses are discussed.

Thermoregulatory Responses to Intermittent Exercise Are Influenced by Knit Structure of Underwear

DTIC Science & Technology

1990-01-01

determined at 120 min, when Swo,(K3) and Swt(K4) were lower compared to both Sw,,(K2) and Swot (K5) 400 (Fig. 3). 300 Skin wettednessEE The knit...dew Pugh LGC (1966) Clothing insulation and accidential hypo- point temperature sensor. J Appl Physiol 52: 1658- 1660 thermia in youth. Nature 209: 1281...insulation. J Appl Physiol 8:539-545 cise and thermal stress. Physiol Rev 54:75-159 Hardy JI), )uBois EF (1938) Basal metabolism, radiation, Saltin B

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 1: January

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-07-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analyses produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of January. Included are global analyses of: (1) Mean temperature standard deviation; (2) Mean geopotential height standard deviation; (3) Mean density standard deviation; (4) Mean density standard deviation (all for 13 levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean dew point standard deviation for the 13 levels; and (6) Jet stream at levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Population trends and flight behavior of the American burying beetle, Nicrophorus americanus (Coleoptera: Silphidae), on Block Island, RI

USGS Publications Warehouse

Raithel, C.J.; Ginsberg, H.S.; Prospero, M.L.

2006-01-01

The endangered American burying beetle, Nicrophorus americanus, was monitored on Block Island, RI, USA, from 1991-2003 using mark-recapture population estimates of adults collected in pitfall traps. Populations increased through time, especially after 1994 when a program was initiated that provided carrion for beetle production. Beetle captures increased with increasing temperature and dew point, and decreased with increasing wind speed. Short distance movement was not related to wind direction, while longer distance flights tended to be downwind. Although many individuals flew considerable distances along transects, most recaptures were in traps near the point of release. These behaviors probably have counterbalancing effects on population estimates.

Accuracy evaluation of ClimGen weather generator and daily to hourly disaggregation methods in tropical conditions

NASA Astrophysics Data System (ADS)

Safeeq, Mohammad; Fares, Ali

2011-12-01

Daily and sub-daily weather data are often required for hydrological and environmental modeling. Various weather generator programs have been used to generate synthetic climate data where observed climate data are limited. In this study, a weather data generator, ClimGen, was evaluated for generating information on daily precipitation, temperature, and wind speed at four tropical watersheds located in Hawai`i, USA. We also evaluated different daily to sub-daily weather data disaggregation methods for precipitation, air temperature, dew point temperature, and wind speed at Mākaha watershed. The hydrologic significance values of the different disaggregation methods were evaluated using Distributed Hydrology Soil Vegetation Model. MuDRain and diurnal method performed well over uniform distribution in disaggregating daily precipitation. However, the diurnal method is more consistent if accurate estimates of hourly precipitation intensities are desired. All of the air temperature disaggregation methods performed reasonably well, but goodness-of-fit statistics were slightly better for sine curve model with 2 h lag. Cosine model performed better than random model in disaggregating daily wind speed. The largest differences in annual water balance were related to wind speed followed by precipitation and dew point temperature. Simulated hourly streamflow, evapotranspiration, and groundwater recharge were less sensitive to the method of disaggregating daily air temperature. ClimGen performed well in generating the minimum and maximum temperature and wind speed. However, for precipitation, it clearly underestimated the number of extreme rainfall events with an intensity of >100 mm/day in all four locations. ClimGen was unable to replicate the distribution of observed precipitation at three locations (Honolulu, Kahului, and Hilo). ClimGen was able to reproduce the distributions of observed minimum temperature at Kahului and wind speed at Kahului and Hilo. Although the weather data generation and disaggregation methods were concentrated in a few Hawaiian watersheds, the results presented can be used to similar mountainous location settings, as well as any specific locations aimed at furthering the site-specific performance evaluation of these tested models.

Environmental Factors Correlated with Culturable Enterococci Concentrations in Tropical Recreational Waters: A Case Study in Escambron Beach, San Juan, Puerto Rico.

PubMed

Laureano-Rosario, Abdiel E; Symonds, Erin M; Rueda-Roa, Digna; Otis, Daniel; Muller-Karger, Frank E

2017-12-19

Enterococci concentration variability at Escambron Beach, San Juan, Puerto Rico, was examined in the context of environmental conditions observed during 2005-2015. Satellite-derived sea surface temperature (SST), turbidity, direct normal irradiance, and dew point were combined with local precipitation, winds, and mean sea level (MSL) observations in a stepwise multiple regression analyses (Akaike Information Criteria model selection). Precipitation, MSL, irradiance, SST, and turbidity explained 20% of the variation in observed enterococci concentrations based upon these analyses. Changes in these parameters preceded increases in enterococci concentrations by 24 h up to 11 days, particularly during positive anomalies of turbidity, SST, and 480-960 mm of accumulated (4 days) precipitation, which relates to bacterial ecology. Weaker, yet still significant, increases in enterococci concentrations were also observed during positive dew point anomalies. Enterococci concentrations decreased with elevated irradiance and MSL anomalies. Unsafe enterococci concentrations per US EPA recreational water quality guidelines occurred when 4-day cumulative precipitation ranged 481-960 mm; irradiance < 667 W·m -2 ; daily average turbidity anomaly >0.005 sr -1 ; SST anomaly >0.8 °C; and 3-day average MSL anomaly <-18.8 cm. This case study shows that satellite-derived environmental data can be used to inform future water quality studies and protect human health.

Design and optimization of integrated gas/condensate plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Root, C.R.; Wilson, J.L.

1995-11-01

An optimized design is demonstrated for combining gas processing and condensate stabilization plants into a single integrated process facility. This integrated design economically provides improved condensate recovery versus use of a simple stabilizer design. A selection matrix showing likely application of this integrated process is presented for use on future designs. Several methods for developing the fluid characterization and for using a process simulator to predict future design compositions are described, which could be useful in other designs. Optimization of flowsheet equipment choices and of design operating pressures and temperatures is demonstrated including the effect of both continuous and discretemore » process equipment size changes. Several similar designs using a turboexpander to provide refrigeration for liquids recovery and stabilizer reflux are described. Operating overthrust and from the P/15-D platform in the Dutch sector of the North Sea has proven these integrated designs are effective. Concerns do remain around operation near or above the critical pressure that should be addressed in future work including providing conservative separator designs, providing sufficient process design safety margin to meet dew point specifications, selecting the most conservative design values of predicted gas dew point and equipment size calculated with different Equations-of-State, and possibly improving the accuracy of PVT calculations in the near critical area.« less

Variational analysis of temperature and moisture advection in a severe storm environment

NASA Technical Reports Server (NTRS)

Mcfarland, M. J.; Sasaki, Y. K.

1977-01-01

Horizontal wind components, potential temperature, and mixing ratio fields associated with a severe storm environment in the south central United States were objectively analyzed from synoptic upper air observations with a nonhomogeneous anisotropic weighting function. The particular case study discussed here is the tornado producting squall line which moved through eastern Oklahoma 26 May 1973. The synoptic situation which preceded squall line development was cyclogenesis and frontogenesis in the lee-of-mountain trough, which produced a well-defined surface dry line (or dew point front) and a pronounced mid-level dry air intrusion. It is shown that the intrusion was also characterized by warm air, with a lapse rate approaching the dry adiabatic.

Leaf wetness distribution within a potato crop

NASA Astrophysics Data System (ADS)

Heusinkveld, B. G.

2010-07-01

The Netherlands has a mild maritime climate and therefore the major interest in leaf wetness is associated with foliar plant diseases. During moist micrometeorological conditions (i.e. dew, fog, rain), foliar fungal diseases may develop quickly and thereby destroy a crop quickly. Potato crop monocultures covering several hectares are especially vulnerable to such diseases. Therefore understanding and predicting leaf wetness in potato crops is crucial in crop disease control strategies. A field experiment was carried out in a large homogeneous potato crop in the Netherlands during the growing season of 2008. Two innovative sensor networks were installed as a 3 by 3 grid at 3 heights covering an area of about 2 hectares within two larger potato crops. One crop was located on a sandy soil and one crop on a sandy peat soil. In most cases leaf wetting starts in the top layer and then progresses downward. Leaf drying takes place in the same order after sunrise. A canopy dew simulation model was applied to simulate spatial leaf wetness distribution. The dew model is based on an energy balance model. The model can be run using information on the above-canopy wind speed, air temperature, humidity, net radiation and within canopy air temperature, humidity and soil moisture content and temperature conditions. Rainfall was accounted for by applying an interception model. The results of the dew model agreed well with the leaf wetness sensors if all local conditions were considered. The measurements show that the spatial correlation of leaf wetness decreases downward.

Theoretical and experimental studies of the deposition of Na2So4 from seeded combustion gases

NASA Technical Reports Server (NTRS)

Kohl, F. J.; Santoro, G. J.; Stearns, C. A.; Fryburg, G. C.; Rosner, D. E.

1977-01-01

Flames in a Mach 0.3 atmospheric pressure laboratory burner rig were doped with sea salt, NaS04, and NaCl, respectively, in an effort to validate theoretical dew point predictions made by a local thermochemical equilibrium (LTCE) method of predicting condensation temperatures of sodium sulfate in flame environments. Deposits were collected on cylindrical platinum targets placed in the combustion products, and the deposition was studied as a function of collector temperature. Experimental deposition onset temperatures checked within experimental error with LTCE-predicted temperatures. A multicomponent mass transfer equation was developed to predict the rate of deposition of Na2SO4(c) via vapor transport at temperatures below the deposition onset temperature. Agreement between maximum deposition rates predicted by this chemically frozen boundary layer (CFBL) theory and those obtained in the seeded laboratory burner experiments is good.

Water potential in excised leaf tissue. Comparison of a commercial dew point hygrometer and a thermocouple psychrometer on soybean, wheat, and barley

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelsen, C.E.; Safir, G.R.; Hanson, A.D.

1978-01-01

Leaf water potential (Psi/sub leaf/) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Psi/sub leaf/ values from the dew point hygrometer were too high. Agreement was improvedmore » by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Psi/sub leaf/ values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status.« less

Time series of canopy intercepted water and dew observed in a tropical tree plantation by means of microwave radiometry

NASA Astrophysics Data System (ADS)

Schneebeli, M.; Wolf, S.; Kunert, N.; Eugster, W.; Mätzler, C.

2012-04-01

During summer and autumn 2007, a 11 GHz microwave radiometer was deployed in an experimental tree plantation in Sardinilla, Panama. With this instrument, the opacity of the tree canopy was derived from incoming brightness temperatures received on the ground. A collocated eddy-covariance flux tower measured water vapor fluxes and meteorological variables above the canopy. It was found that canopy intercepted rain and dew formation modulated the diurnal opacity cycle. With an enhanced canopy opacity model accounting for water deposited on the leaves, we quantified the influence of canopy stored water (i.e. intercepted water and dew) on the opacity. With this technique it was possible to directly monitor high resolution time series of dew formation and rain interception during a period of two weeks. In contrast to through-fall measurements, this new technique allows to determine the amount of intercepted rain more precisely and during day and night since evaporation effects do not hamper the accuracy of the method. We found that during light rainfall up to 60% of the rain amount is intercepted by the canopy whereas during periods of intense rainfall, only 4% were intercepted. On average, about 15% of the rain amount was intercepted during rainfalls of medium intensities. By comparing the interception with the water vapor flux time series it was found that intercepted water is evaporated rapidly after it is deposited on the leaves, which resulted in an enhanced water vapor flux. Our study also provides the first direct measurements and quantifications of the temporal evolution of dew formation and evaporation in a tree canopy on a diurnal base. Dew accumulated during the night and until about 2 h after sunrise, when the water vapor flux began to exceed the dew formation rate. The dew continued to evaporate for another 3.5 h until the surface of the leaves was completely dry. On average, 0.17 mm of dew was formed during the night. Dew evaporation contributed 5% to the total water vapor flux measured above the canopy.

Investigation of the stochastic nature of temperature and humidity for energy management

NASA Astrophysics Data System (ADS)

Hadjimitsis, Evanthis; Demetriou, Evangelos; Sakellari, Katerina; Tyralis, Hristos; Iliopoulou, Theano; Koutsoyiannis, Demetris

2017-04-01

Atmospheric temperature and dew point, in addition to their role in atmospheric processes, influence the management of energy systems since they highly affect the energy demand and production. Both temperature and humidity depend on the climate conditions and geographical location. In this context, we analyze numerous of observations around the globe and we investigate the long-term behaviour and periodicities of the temperature and humidity processes. Also, we present and apply a parsimonious stochastic double-cyclostationary model for these processes to an island in the Aegean Sea and investigate their link to energy management. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

Dew point temperature affects ascospore release of allergenic genus Leptosphaeria

NASA Astrophysics Data System (ADS)

Sadyś, Magdalena; Kaczmarek, Joanna; Grinn-Gofron, Agnieszka; Rodinkova, Victoria; Prikhodko, Alex; Bilous, Elena; Strzelczak, Agnieszka; Herbert, Robert J.; Jedryczka, Malgorzata

2018-06-01

The genus Leptosphaeria contains numerous fungi that cause the symptoms of asthma and also parasitize wild and crop plants. In search of a robust and universal forecast model, the ascospore concentration in air was measured and weather data recorded from 1 March to 31 October between 2006 and 2012. The experiment was conducted in three European countries of the temperate climate, i.e., Ukraine, Poland, and the UK. Out of over 150 forecast models produced using artificial neural networks (ANNs) and multivariate regression trees (MRTs), we selected the best model for each site, as well as for joint two-site combinations. The performance of all computed models was tested against records from 1 year which had not been used for model construction. The statistical analysis of the fungal spore data was supported by a comprehensive study of both climate and land cover within a 30-km radius from the air sampler location. High-performance forecasting models were obtained for individual sites, showing that the local micro-climate plays a decisive role in biology of the fungi. Based on the previous epidemiological studies, we hypothesized that dew point temperature (DPT) would be a critical factor in the models. The impact of DPT was confirmed only by one of the final best neural models, but the MRT analyses, similarly to the Spearman's rank test, indicated the importance of DPT in all but one of the studied cases and in half of them ranked it as a fundamental factor. This work applies artificial neural modeling to predict the Leptosphaeria airborne spore concentration in urban areas for the first time.

Dew point temperature affects ascospore release of allergenic genus Leptosphaeria

NASA Astrophysics Data System (ADS)

Sadyś, Magdalena; Kaczmarek, Joanna; Grinn-Gofron, Agnieszka; Rodinkova, Victoria; Prikhodko, Alex; Bilous, Elena; Strzelczak, Agnieszka; Herbert, Robert J.; Jedryczka, Malgorzata

2018-01-01

The genus Leptosphaeria contains numerous fungi that cause the symptoms of asthma and also parasitize wild and crop plants. In search of a robust and universal forecast model, the ascospore concentration in air was measured and weather data recorded from 1 March to 31 October between 2006 and 2012. The experiment was conducted in three European countries of the temperate climate, i.e., Ukraine, Poland, and the UK. Out of over 150 forecast models produced using artificial neural networks (ANNs) and multivariate regression trees (MRTs), we selected the best model for each site, as well as for joint two-site combinations. The performance of all computed models was tested against records from 1 year which had not been used for model construction. The statistical analysis of the fungal spore data was supported by a comprehensive study of both climate and land cover within a 30-km radius from the air sampler location. High-performance forecasting models were obtained for individual sites, showing that the local micro-climate plays a decisive role in biology of the fungi. Based on the previous epidemiological studies, we hypothesized that dew point temperature (DPT) would be a critical factor in the models. The impact of DPT was confirmed only by one of the final best neural models, but the MRT analyses, similarly to the Spearman's rank test, indicated the importance of DPT in all but one of the studied cases and in half of them ranked it as a fundamental factor. This work applies artificial neural modeling to predict the Leptosphaeria airborne spore concentration in urban areas for the first time.

Dew point temperature affects ascospore release of allergenic genus Leptosphaeria.

PubMed

Sadyś, Magdalena; Kaczmarek, Joanna; Grinn-Gofron, Agnieszka; Rodinkova, Victoria; Prikhodko, Alex; Bilous, Elena; Strzelczak, Agnieszka; Herbert, Robert J; Jedryczka, Malgorzata

2018-06-01

The genus Leptosphaeria contains numerous fungi that cause the symptoms of asthma and also parasitize wild and crop plants. In search of a robust and universal forecast model, the ascospore concentration in air was measured and weather data recorded from 1 March to 31 October between 2006 and 2012. The experiment was conducted in three European countries of the temperate climate, i.e., Ukraine, Poland, and the UK. Out of over 150 forecast models produced using artificial neural networks (ANNs) and multivariate regression trees (MRTs), we selected the best model for each site, as well as for joint two-site combinations. The performance of all computed models was tested against records from 1 year which had not been used for model construction. The statistical analysis of the fungal spore data was supported by a comprehensive study of both climate and land cover within a 30-km radius from the air sampler location. High-performance forecasting models were obtained for individual sites, showing that the local micro-climate plays a decisive role in biology of the fungi. Based on the previous epidemiological studies, we hypothesized that dew point temperature (DPT) would be a critical factor in the models. The impact of DPT was confirmed only by one of the final best neural models, but the MRT analyses, similarly to the Spearman's rank test, indicated the importance of DPT in all but one of the studied cases and in half of them ranked it as a fundamental factor. This work applies artificial neural modeling to predict the Leptosphaeria airborne spore concentration in urban areas for the first time.

Insights into mountain precipitation and snowpack from a basin-scale wireless-sensor network

NASA Astrophysics Data System (ADS)

Zhang, Z.; Glaser, S.; Bales, R.; Conklin, M.; Rice, R.; Marks, D.

2017-08-01

A spatially distributed wireless-sensor network, installed across the 2154 km2 portion of the 5311 km2 American River basin above 1500 m elevation, provided spatial measurements of temperature, relative humidity, and snow depth in the Sierra Nevada, California. The network consisted of 10 sensor clusters, each with 10 measurement nodes, distributed to capture the variability in topography and vegetation cover. The sensor network captured significant spatial heterogeneity in rain versus snow precipitation for water-year 2014, variability that was not apparent in the more limited operational data. Using daily dew-point temperature to track temporal elevational changes in the rain-snow transition, the amount of snow accumulation at each node was used to estimate the fraction of rain versus snow. This resulted in an underestimate of total precipitation below the 0°C dew-point elevation, which averaged 1730 m across 10 precipitation events, indicating that measuring snow does not capture total precipitation. We suggest blending lower elevation rain gauge data with higher-elevation sensor-node data for each event to estimate total precipitation. Blended estimates were on average 15-30% higher than using either set of measurements alone. Using data from the current operational snow-pillow sites gives even lower estimates of basin-wide precipitation. Given the increasing importance of liquid precipitation in a warming climate, a strategy that blends distributed measurements of both liquid and solid precipitation will provide more accurate basin-wide precipitation estimates, plus spatial and temporal patters of snow accumulation and melt in a basin.

Effects of temperature at constant air dew point on leaf carboxylation efficiency and CO2 compensation point of different leaf types.

PubMed

Weber, J A; Tenhunen, J D; Lange, O L

1985-09-01

The effect of temperature on photosynthesis at constant water-vapor pressure in the air was investigated using two sclerophyll species, Arbutus unedo and Quercus suber, and one mesophytic species, Spinacia oleracea. Photosynthesis and transpiration were measured over a range of temperatures, 20-39° C. The external concentration of CO2 was varied from 340 μbar to near CO2 compensation. The initial slope (carboxylation efficiency, CE) of the photosynthetic response to intercellular CO2 concentration, the CO2 compensation point (Γ), and the extrapolated rate of CO2 released into CO2-free air (R i) were calculated. At an external CO2 concentration of 320-340 μbar CO2, photosynthesis decreased with temperature in all species. The effect of temperature on Γ was similar in all species. While CE in S. oleracea changed little with temperature, CE decreased by 50% in Q. suber as temperature increased from 25 to 34° C. Arbutus unedo also exhibited a decrease in CE at higher temperatures but not as marked as Q. suber. The absolut value of R i increased with temperature in S. oleracea, while changing little or decreasing in the sclerophylls. Variations in Γ and R i of the sclerophyll species are not consistent with greater increase of respiration with temperature in the light in these species compared with S. oleracea.

Stochastic investigation of temperature process for climatic variability identification

NASA Astrophysics Data System (ADS)

Lerias, Eleutherios; Kalamioti, Anna; Dimitriadis, Panayiotis; Markonis, Yannis; Iliopoulou, Theano; Koutsoyiannis, Demetris

2016-04-01

The temperature process is considered as the most characteristic hydrometeorological process and has been thoroughly examined in the climate-change framework. We use a dataset comprising hourly temperature and dew point records to identify statistical variability with emphasis on the last period. Specifically, we investigate the occurrence of mean, maximum and minimum values and we estimate statistical properties such as marginal probability distribution function and the type of decay of the climacogram (i.e., mean process variance vs. scale) for various time periods. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

Benchmark Data Set for Wheat Growth Models: Field Experiments and AgMIP Multi-Model Simulations.

NASA Technical Reports Server (NTRS)

Asseng, S.; Ewert, F.; Martre, P.; Rosenzweig, C.; Jones, J. W.; Hatfield, J. L.; Ruane, A. C.; Boote, K. J.; Thorburn, P.J.; Rotter, R. P.

2015-01-01

The data set includes a current representative management treatment from detailed, quality-tested sentinel field experiments with wheat from four contrasting environments including Australia, The Netherlands, India and Argentina. Measurements include local daily climate data (solar radiation, maximum and minimum temperature, precipitation, surface wind, dew point temperature, relative humidity, and vapor pressure), soil characteristics, frequent growth, nitrogen in crop and soil, crop and soil water and yield components. Simulations include results from 27 wheat models and a sensitivity analysis with 26 models and 30 years (1981-2010) for each location, for elevated atmospheric CO2 and temperature changes, a heat stress sensitivity analysis at anthesis, and a sensitivity analysis with soil and crop management variations and a Global Climate Model end-century scenario.

Microwave Determination of Water Mole Fraction in Humid Gas Mixtures

NASA Astrophysics Data System (ADS)

Cuccaro, R.; Gavioso, R. M.; Benedetto, G.; Madonna Ripa, D.; Fernicola, V.; Guianvarc'h, C.

2012-09-01

A small volume (65 cm3) gold-plated quasi-spherical microwave resonator has been used to measure the water vapor mole fraction x w of H2O/N2 and H2O/air mixtures. This experimental technique exploits the high precision achievable in the determination of the cavity microwave resonance frequencies and is particularly sensitive to the presence of small concentrations of water vapor as a result of the high polarizability of this substance. The mixtures were prepared using the INRIM standard humidity generator for frost-point temperatures T fp in the range between 241 K and 270 K and a commercial two-pressure humidity generator operated at a dew-point temperature between 272 K and 291 K. The experimental measurements compare favorably with the calculated molar fractions of the mixture supplied by the humidity generators, showing a normalized error lower than 0.8.

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 7: July

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-07-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analysis produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of July. Included are global analyses of: (1) Mean temperature/standard deviation; (2) Mean geopotential height/standard deviation; (3) Mean density/standard deviation; (4) Height and vector standard deviation (all at 13 pressure levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean dew point standard deviation at levels 1000 through 30 mb; and (6) Jet stream at levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 10: October

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-07-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analysis produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of October. Included are global analyses of: (1) Mean temperature/standard deviation; (2) Mean geopotential height/standard deviation; (3) Mean density/standard deviation; (4) Height and vector standard deviation (all at 13 pressure levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean dew point/standard deviation at levels 1000 through 30 mb; and (6) Jet stream at levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 3: March

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-11-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analysis produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of March. Included are global analyses of: (1) Mean Temperature Standard Deviation; (2) Mean Geopotential Height Standard Deviation; (3) Mean Density Standard Deviation; (4) Height and Vector Standard Deviation (all for 13 pressure levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean Dew Point Standard Deviation for levels 1000 through 30 mb; and (6) Jet stream for levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 2: February

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-09-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analyses produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of February. Included are global analyses of: (1) Mean temperature standard deviation; (2) Mean geopotential height standard deviation; (3) Mean density standard deviation; (4) Height and vector standard deviation (all for 13 pressure levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean dew point standard deviation for the 13 levels; and (6) Jet stream for levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Joint US Navy/US Air Force climatic study of the upper atmosphere. Volume 4: April

NASA Astrophysics Data System (ADS)

Changery, Michael J.; Williams, Claude N.; Dickenson, Michael L.; Wallace, Brian L.

1989-07-01

The upper atmosphere was studied based on 1980 to 1985 twice daily gridded analyses produced by the European Centre for Medium Range Weather Forecasts. This volume is for the month of April. Included are global analyses of: (1) Mean temperature standard deviation; (2) Mean geopotential height standard deviation; (3) Mean density standard deviation; (4) Height and vector standard deviation (all for 13 pressure levels - 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30 mb); (5) Mean dew point standard deviation for the 13 levels; and (6) Jet stream for levels 500 through 30 mb. Also included are global 5 degree grid point wind roses for the 13 pressure levels.

Analysis and forecast experiments incorporating satellite soundings and cloud and water vapor drift wind information

NASA Technical Reports Server (NTRS)

Goodman, Brian M.; Diak, George R.; Mills, Graham A.

1986-01-01

A system for assimilating conventional meteorological data and satellite-derived data in order to produce four-dimensional gridded data sets of the primary atmospheric variables used for updating limited area forecast models is described. The basic principles of a data assimilation scheme as proposed by Lorenc (1984) are discussed. The design of the system and its incremental assimilation cycles are schematically presented. The assimilation system was tested using radiosonde, buoy, VAS temperature, dew point, gradient wind data, cloud drift, and water vapor motion data. The rms vector errors for the data are analyzed.

Possible Role of Pectin-containing Mucilage and Dew in Repairing Embryo DNA of Seeds Adapted to Desert Conditions

PubMed Central

Huang, Zhenying; Boubriak, Ivan; Osborne, Daphne J.; Dong, Ming; Gutterman, Yitzchak

2008-01-01

Background and Aims Repair of damage to DNA of seed embryos sustained during long periods of quiescence under dry desert conditions is important for subsequent germination. The possibility that repair of embryo DNA can be facilitated by small amounts of water derived from dew temporarily captured at night by pectinaceous surface pellicles was tested. These pellicles are secreted during early seed development and form mucilage when hydrated. Methods Seeds of Artemisia sphaerocephala and Artemisia ordosica were collected from a sandy desert. Their embryos were damaged by gamma radiation to induce a standard level of DNA damage. The treated seeds were then exposed to nocturnal dew deposition on the surface of soil in the Negev desert highlands. The pellicles were removed from some seeds and left intact on others to test the ability of mucilage to support repair of the damaged DNA when night-time humidity and temperature favoured dew formation. Repair was assessed from fragmentation patterns of extracted DNA on agarose gels. Key Results For A. sphaerocephala, which has thick seed pellicles, DNA repair occurred in seeds with intact pellicles after 50 min of cumulative night dew formation, but not in seeds from which the pellicles had been removed. For A. ordosica, which has thin seed pellicles, DNA repair took at least 510 min of cumulative night dewing to achieve partial recovery of DNA integrity. The mucilage has the ability to rehydrate after daytime dehydration. Conclusions The ability of seeds to develop a mucilaginous layer when wetted by night-time dew, and to repair their DNA under these conditions, appear to be mechanisms that help maintain seed viability under harsh desert conditions. PMID:17495979

Possible role of pectin-containing mucilage and dew in repairing embryo DNA of seeds adapted to desert conditions.

PubMed

Huang, Zhenying; Boubriak, Ivan; Osborne, Daphne J; Dong, Ming; Gutterman, Yitzchak

2008-01-01

Repair of damage to DNA of seed embryos sustained during long periods of quiescence under dry desert conditions is important for subsequent germination. The possibility that repair of embryo DNA can be facilitated by small amounts of water derived from dew temporarily captured at night by pectinaceous surface pellicles was tested. These pellicles are secreted during early seed development and form mucilage when hydrated. Seeds of Artemisia sphaerocephala and Artemisia ordosica were collected from a sandy desert. Their embryos were damaged by gamma radiation to induce a standard level of DNA damage. The treated seeds were then exposed to nocturnal dew deposition on the surface of soil in the Negev desert highlands. The pellicles were removed from some seeds and left intact on others to test the ability of mucilage to support repair of the damaged DNA when night-time humidity and temperature favoured dew formation. Repair was assessed from fragmentation patterns of extracted DNA on agarose gels. For A. sphaerocephala, which has thick seed pellicles, DNA repair occurred in seeds with intact pellicles after 50 min of cumulative night dew formation, but not in seeds from which the pellicles had been removed. For A. ordosica, which has thin seed pellicles, DNA repair took at least 510 min of cumulative night dewing to achieve partial recovery of DNA integrity. The mucilage has the ability to rehydrate after daytime dehydration. The ability of seeds to develop a mucilaginous layer when wetted by night-time dew, and to repair their DNA under these conditions, appear to be mechanisms that help maintain seed viability under harsh desert conditions.

Analysis and Design of a High Power Laser Adaptive Phased Array Transmitter

DTIC Science & Technology

1977-12-01

Report Number Assigned by Contract Monitor: SLL 80-711; CR75-537/501 Comments on Document: Archive, RRI, DEW Descriptors, Keywords: Analysis Design...Document: DEW j ^ yrf^N H tpm *■ ww CRT»5g:’’""J{ it.. 2. Government Accession No. 3. Recipient’s Catalog No. 4. Title and Subtitle Analysis...Target Plane (e = 0, Range = 185000 M, Five 0.96 M Subapertures, Pointing Plus Phase Adaption for 10.6 pm Propagation in Vacuum) ... 80 :il-14

A Summary of Meteorological Parameters During Space Shuttle Pad Exposure Periods

NASA Technical Reports Server (NTRS)

Overbey, Glenn; Roberts, Barry C.

2005-01-01

During the 113 missions of the Space Transportation System (STS), the Space Shuffle fleet has been exposed to the elements on the launch pad for a total of 4195 days. The Natural Environments Branch at Marshall Space Flight Center archives atmospheric environments to which the Space Shuttle vehicles are exposed. This paper provides a summary of the historical record of the meteorological conditions encountered by the Space Shuttle fleet during the pad exposure period. Sources of the surface parameters, including temperature, dew point temperature, relative humidity, wind speed, wind direction, sea level pressure and precipitation are presented. Data is provided from the first launch of the STS in 1981 through the launch of STS-107 in 2003.

Daily reference crop evapotranspiration with reduced data sets in the humid environments of Azores islands using estimates of actual vapor pressure, solar radiation, and wind speed

NASA Astrophysics Data System (ADS)

Paredes, P.; Fontes, J. C.; Azevedo, E. B.; Pereira, L. S.

2017-11-01

Reference crop evapotranspiration (ETo) estimations using the FAO Penman-Monteith equation (PM-ETo) require a set of weather data including maximum and minimum air temperatures (T max, T min), actual vapor pressure (e a), solar radiation (R s), and wind speed (u 2). However, those data are often not available, or data sets are incomplete due to missing values. A set of procedures were proposed in FAO56 (Allen et al. 1998) to overcome these limitations, and which accuracy for estimating daily ETo in the humid climate of Azores islands is assessed in this study. Results show that after locally and seasonally calibrating the temperature adjustment factor a d used for dew point temperature (T dew) computation from mean temperature, ETo estimations shown small bias and small RMSE ranging from 0.15 to 0.53 mm day-1. When R s data are missing, their estimation from the temperature difference (T max-T min), using a locally and seasonal calibrated radiation adjustment coefficient (k Rs), yielded highly accurate ETo estimates, with RMSE averaging 0.41 mm day-1 and ranging from 0.33 to 0.58 mm day-1. If wind speed observations are missing, the use of the default u 2 = 2 m s-1, or 3 m s-1 in case of weather measurements over clipped grass in airports, revealed appropriated even for the windy locations (u 2 > 4 m s-1), with RMSE < 0.36 mm day-1. The appropriateness of procedure to estimating the missing values of e a, R s, and u 2 was confirmed.

Environmental Factors Correlated with Culturable Enterococci Concentrations in Tropical Recreational Waters: A Case Study in Escambron Beach, San Juan, Puerto Rico

PubMed Central

Rueda-Roa, Digna; Otis, Daniel; Muller-Karger, Frank E.

2017-01-01

Enterococci concentration variability at Escambron Beach, San Juan, Puerto Rico, was examined in the context of environmental conditions observed during 2005–2015. Satellite-derived sea surface temperature (SST), turbidity, direct normal irradiance, and dew point were combined with local precipitation, winds, and mean sea level (MSL) observations in a stepwise multiple regression analyses (Akaike Information Criteria model selection). Precipitation, MSL, irradiance, SST, and turbidity explained 20% of the variation in observed enterococci concentrations based upon these analyses. Changes in these parameters preceded increases in enterococci concentrations by 24 h up to 11 days, particularly during positive anomalies of turbidity, SST, and 480–960 mm of accumulated (4 days) precipitation, which relates to bacterial ecology. Weaker, yet still significant, increases in enterococci concentrations were also observed during positive dew point anomalies. Enterococci concentrations decreased with elevated irradiance and MSL anomalies. Unsafe enterococci concentrations per US EPA recreational water quality guidelines occurred when 4-day cumulative precipitation ranged 481–960 mm; irradiance < 667 W·m−2; daily average turbidity anomaly >0.005 sr−1; SST anomaly >0.8 °C; and 3-day average MSL anomaly <−18.8 cm. This case study shows that satellite-derived environmental data can be used to inform future water quality studies and protect human health. PMID:29257092

Effects of meteorological conditions on spore plumes

NASA Astrophysics Data System (ADS)

Burch, M.; Levetin, E.

2002-05-01

Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard spore traps at several sampling stations. This study involved the examination of the hourly spore concentrations on days that had average daily concentrations near 50,000 spores/m3 or greater. Hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined on 4 days at three sites and then correlated with hourly meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. On each of these days there was a spore plume, a phenomenon in which spore concentrations increased dramatically over a very short period of time. Spore plumes generally occurred near midday, and concentrations were seen to increase from lows around 20,000 total spores/m3 to highs over 170,000 total spores/m3 in 2 h. Multiple regression analysis of the data indicated that increases in temperature, dew point, and air pressure correlated with the increase in spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as on 3 of the 4 days when spore plumes occurred there were thunderstorms later that evening. The occurrence of spore plumes may have clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.

High-resolution grids of hourly meteorological variables for Germany

NASA Astrophysics Data System (ADS)

Krähenmann, S.; Walter, A.; Brienen, S.; Imbery, F.; Matzarakis, A.

2018-02-01

We present a 1-km2 gridded German dataset of hourly surface climate variables covering the period 1995 to 2012. The dataset comprises 12 variables including temperature, dew point, cloud cover, wind speed and direction, global and direct shortwave radiation, down- and up-welling longwave radiation, sea level pressure, relative humidity and vapour pressure. This dataset was constructed statistically from station data, satellite observations and model data. It is outstanding in terms of spatial and temporal resolution and in the number of climate variables. For each variable, we employed the most suitable gridding method and combined the best of several information sources, including station records, satellite-derived data and data from a regional climate model. A module to estimate urban heat island intensity was integrated for air and dew point temperature. Owing to the low density of available synop stations, the gridded dataset does not capture all variations that may occur at a resolution of 1 km2. This applies to areas of complex terrain (all the variables), and in particular to wind speed and the radiation parameters. To achieve maximum precision, we used all observational information when it was available. This, however, leads to inhomogeneities in station network density and affects the long-term consistency of the dataset. A first climate analysis for Germany was conducted. The Rhine River Valley, for example, exhibited more than 100 summer days in 2003, whereas in 1996, the number was low everywhere in Germany. The dataset is useful for applications in various climate-related studies, hazard management and for solar or wind energy applications and it is available via doi: 10.5676/DWD_CDC/TRY_Basis_v001.

Lightweight dew-/frost-point hygrometer based on a surface-acoustic-wave sensor for balloon-borne atmospheric water vapor profile sounding

NASA Astrophysics Data System (ADS)

Hansford, Graeme M.; Freshwater, Ray A.; Eden, Louise; Turnbull, Katharine F. V.; Hadaway, David E.; Ostanin, Victor P.; Jones, Roderic L.

2006-01-01

The design of a very lightweight dew-/frost-point hygrometer for balloon-borne atmospheric water vapor profiling is described. The instrument is based on a surface-acoustic-wave sensor. The low instrument weight is a key feature, allowing flights on meteorological balloons which brings many more flight opportunities. The hygrometer shows consistently good performance in the troposphere and while water vapor measurements near the tropopause and in the stratosphere are possible with the current instrument, the long-time response in these regions hampers realistic measurements. The excellent intrinsic sensitivity of the surface-acoustic-wave sensor should permit considerable improvement in the hygrometer performance in the very dry regions of the atmosphere.

A dew point signaller for conservation of works of art.

PubMed

Camuffo, D; Valcher, S

1986-03-01

All works of art, from paintings, frescoes, sculptures, to monuments and buildings, are affected by diurnal and seasonal variations of the local microclimate, which induce interactions with the environmental atmosphere. Heat and vapour exchanges cause fluxes of heat and mass between the surface and the atmosphere, and may favour the agressivity of environmental pollutants. Condensation-evaporation cycles are recognized as being very important processes which adversely affect the life-time of the work of art. The need to control the microclimate or to stop condensation processes has been resolved by means of a dew-point signaller especially designed to overcome this problem. This paper discusses the characteristics of this device as well as the environmental philosophy which should be followed when conserving works of art.

Novel radiator for carbon dioxide absorbents in low-flow anesthesia.

PubMed

Hirabayashi, Go; Mitsui, Takanori; Kakinuma, Takayasu; Ogihara, Yukihiko; Matsumoto, Shohei; Isshiki, Atsushi; Yasuo, Watanabe

2003-01-01

During long-term low-flow sevoflurane anesthesia, dew formation and the generation of compound A are increased in the anesthesia circuit because of elevated soda lime temperature. The object of this study was to develop a novel radiator for carbon dioxide absorbents used for long durations of low-flow sevoflurane anesthesia. Eleven female swine were divided into two groups comprising a "radiator" group (n = 5) that used a novel radiator for carbon dioxide absorbents and a "control" group (n = 6) that used a conventional canister. Anesthesia was maintained with N2O, O2, and sevoflurane, and low-flow anesthesia was performed with fresh gas flow at 0.6 L/min for 12 hr. In the "control" group, the soda lime temperature reached more than 40 degrees C and soda lime dried up with severe dew formation in the inspiratory valve. In the "radiator" group, the temperature of soda lime stayed at 30 degrees C, and the water content of soda lime was retained with no dew formation in the inspiratory valve. In addition, compound A concentration was reduced. In conclusion, radiation of soda lime reduced the amounts of condensation formed and the concentration of compound A in the anesthetic circuit, and allowed long term low-flow anesthesia without equipment malfunction.

Spatiotemporal Variability of Humidity Across the Contiguous United States and Southern Canada Using Regional Networks

NASA Astrophysics Data System (ADS)

Behnke, Ruben John

The objective of this dissertation was to show that there is now enough observed humidity data available so that estimates of humidity, along with their necessary assumptions, can be replaced by measured humidity data. The range of applications that depend on humidity data is huge, ranging from water use efficiency of plants and plant stress to human health and agricultural practices. Biases due to the use of estimated humidity can be expected to have short and long impacts, decreasing the accuracy and precision of these, and many other, applications. Data from local, regional, and national observation networks was gathered, and custom quality control routines were written to remove bad data points from over 45000 stations, leaving 12533 usable stations. While still not at the same number of observations as temperature or precipitation, this number is nearly ten times as high as two decades ago. The work I performed consists of three major components, corresponding to the three main chapters of this dissertation. In chapter one, I describe data sources and quality control methods, along with some basic statistics of humidity, describing which geographic variables often used to predict temperature and precipitation can be used to do the same for humidity. Chapter two defines specific diurnal patterns (or "types") of dew point across the United States, including their attributes, causes, and potential influences. Chapter three analyzes biases in evapotranspiration, heat indices, and relative humidity levels that are a direct result of using estimated humidity data. Chapter four discusses contributions this work makes to the scientific community, and potential further research to build on what is presented here. While it may seem that the science of humidity should be well beyond data gathering and bias analysis, the fact remains that humidity is still very commonly estimated through the use of minimum temperature, and diurnal changes in dew point are often ignored. My hope is that this work makes a dent in often deeply entrenched practices, leading others to make the effort to incorporate measured humidity data into their work and study.

Performance characterization of a Bosch CO sub 2 reduction subsystem

NASA Technical Reports Server (NTRS)

Heppner, D. B.; Hallick, T. M.; Schubert, F. H.

1980-01-01

The performance of Bosch hardware at the subsystem level (up to five-person capacity) in terms of five operating parameters was investigated. The five parameters were: (1) reactor temperature, (2) recycle loop mass flow rate, (3) recycle loop gas composition (percent hydrogen), (4) recycle loop dew point and (5) catalyst density. Experiments were designed and conducted in which the five operating parameters were varied and Bosch performance recorded. A total of 12 carbon collection cartridges provided over approximately 250 hours of operating time. Generally, one cartridge was used for each parameter that was varied. The Bosch hardware was found to perform reliably and reproducibly. No startup, reaction initiation or carbon containment problems were observed. Optimum performance points/ranges were identified for the five parameters investigated. The performance curves agreed with theoretical projections.

Miscellaneous methods for measuring matric or water potential

USGS Publications Warehouse

Scanlon, Bridget R.; Andraski, Brian J.; Bilskie, Jim; Dane, Jacob H.; Topp, G. Clarke

2002-01-01

A variety of techniques to measure matric potential or water potential in the laboratory and in the field are described in this section. The techniques described herein require equilibration of some medium whose matric or water potential can be determined from previous calibration or can be measured directly. Under equilibrium conditions the matric or water potential of the medium is equal to that of the soil. The techniques can be divided into: (i) those that measure matric potential and (ii) those that measure water potential (sum of matric and osmotic potentials). Matric potential is determined when the sensor matrix is in direct contact with the soil, so salts are free to diffuse in or out of the sensor matrix, and the equilibrium measurement therefore reflects matric forces acting on the water. Water potential is determined when the sensor is separated from the soil by a vapor gap, so salts are not free to move in or out of the sensor, and the equilibrium measurement reflects the sum of the matric and osmotic forces acting on the water.Seven different techniques are described in this section. Those that measure matric potential include (i) heat dissipation sensors, (ii) electrical resistance sensors, (iii) frequency domain and time domain sensors, and (iv) electro-optical switches. A method that can be used to measure matric potential or water potential is the (v) filter paper method. Techniques that measure water potential include (vi) the Dew Point Potentiameter (Decagon Devices, Inc., Pullman, WA1) (water activity meter) and (vii) vapor equilibration.The first four techniques are electronically based methods for measuring matric potential. Heat dissipation sensors and electrical resistance sensors infer matric potential from previously determined calibration relations between sensor heat dissipation or electrical resistance and matric potential. Frequency-domain and timedomain matric potential sensors measure water content, which is related to matric potential of the sensor through calibration. Electro-optical switches measure changes in light transmission through thin, nylon filters as they absorb or desorb water in response to changes in matric potential. Heat dissipation sensors and electrical resistance sensors are used primarily in the field to provide information on matric potential. Frequency domain matric potential sensors are new and have not been widely used. Time domain matric potential sensors and electro-optical switches are new and have not been commercialized. For the fifth technique, filter paper is used as the standard matrix. The filter paper technique measures matric potential when the filter paper is in direct contact with soil or water potential when separated from soil by a vapor gap. The Dew Point Potentiameter calculates water potential from the measured dew point and sample temperature. The vapor equilibration technique involves equilibration of soil samples with salt solutions of known osmotic potential. The filter paper, Dew Point Potentiameter, and vapor equilibration techniques are generally used in the laboratory to measure water potential of disturbed field samples or to measure water potential for water retention functions.

On the contribution of atmospheric moisture to dew formation

NASA Astrophysics Data System (ADS)

Garratt, J. R.; Segal, M.

1988-09-01

The relative contributions of dewfall (a flux of water vapour from air to surface) and distillation (a flux of water vapour from soil to canopy) to dew formation on closed canopy and bare soil surfaces are assessed, and the dependence of dew amount upon wind speed, absolute temperature, atmospheric stability, relative humidity, soil characteristics and cloudiness, all of which are significant factors, is evaluated. Some of these evaluations provide refinements to similar ones given in Monteith (1961). High dewfall rates are usually ≲0.06 mm hr-1 over canopy or bare soil, though upon a canopy under soil-saturated and air-saturated conditions, rates of dew formation may reach 0.07 0.09 mm hr-1 with contributions from distillation. Various sets of observations are reanalyzed to illustrate the importance of the horizontal advection of moisture in the nocturnal boundary layer (NBL) to observed high rates of dew formation arising from the atmospheric contribution of water vapour (dewfall). These locally observed high dewfall rates must be the result of small-scale or mesoscale horizontal advection of moisture in the NBL, since the humidity changes within the typically shallow NBL required to balance the loss of water at the surface are not observed. Over extensive areas of uniform surface (horizontal scales ≫10 km), such continuously high dewfall rates could only be balanced by a local supply of atmospheric moisture since advection of moisture would necessarily be small.

Functional improvements in dried egg white through the Maillard reaction.

PubMed

Handa, A; Kuroda, N

1999-05-01

The effects of the Maillard reaction on the functional properties of dried egg white (DEW) were investigated. Maillard-reacted DEW (M-DEW) was prepared by storing sugar-preserved DEW (SP-DEW) at 55 degrees C and 35% relative humidity for 0-12 days. The M-DEW developed an excellent gelling property, and hydrogen sulfide production from heat-induced M-DEW gels decreased. Surface sulfhydryl (SH) group content of M-DEW increased while total SH group and alpha-helix contents decreased with increasing heating time in the dry state. Breaking strength, breaking strain, water-holding capacity, and hydrogen sulfide of heat-induced M-DEW gels significantly correlated with surface and total SH group contents in M-DEW. SDS-PAGE revealed that M-DEW proteins were polymerized in which covalent bonds were involved. The present study demonstrated that the Maillard reaction partially unfolds and polymerizes proteins of SP-DEW and, consequently, improved gelling property of SP-DEW under certain controlled conditions.

Will the warmer temperature bring the more intensity precipitation?

NASA Astrophysics Data System (ADS)

Yutong, Z., II; Wang, T.

2017-12-01

Will the warmer temperature bring the more intensity precipitation?Over the past several decades, changes in climate are amplified over the Tibetan Plateau(TP), with warming trend almost being twice as large as the global average. In sharp contrast, there is a large spatial discrepancy of the variations in precipitation extremes, with increasing trends found in the southern and decreasing trends in central TP. These features motivate are urgent need for an observation-based understanding of how precipitation extremes respond to climate change. Here we examine the relation between precipitation intensity with atmospheric temperature, dew point temperature (Td) and convective available potential energy (CAPE) in Tibet Plateau. Owing to the influences of the westerlies and Indian monsoon on Tibetan climate, the stations can be divided into three sub-regions in TP: the westerlies region (north of 35°N, N = 28), the monsoon region (south of 30°N in TP, N = 31), and the transition region (located between 30°N and 35°N, N = 48). We found that the intensity precipitation does not follow the C-C relation and there is a mix of positive and negative slope. To better understand why different scaling occurs with temperature in district region, using the dew point temperature replace the temperature, although there is significant variability in relative humidity values, at most stations, there appears to be a general increase in relative humidity associated. It is likely that the observed rise in relative humidity can assist in explaining the negative scaling of extreme precipitation at westerlies domain and monsoon domain, with the primary reason why precipitation extremes expected to increase follows from the fact that a warmer atmosphere can "hold" more moisture. This suggests that not only on how much the moisture the atmosphere can hold, but on how much moisture exits in atmosphere. To understand the role of dynamic on extreme precipitation, we repeat the precipitation intense analysis using ln(CAPE) as regression. The CAPE is the vertical integral of parcel buoyancy between the level of free convection and level of neutral buoyancy. We find almost all pixels are positive and pass through the 0.05 confidence limit. We can conclude that the intensity of moist convection is an important for the extreme precipitation.

User's manual for a computer program for the emulation/simulation of a space station Environmental Control and Life Support System (ESCM)

NASA Technical Reports Server (NTRS)

Yanosy, James L.

1988-01-01

This manual describes how to use the Emulation Simulation Computer Model (ESCM). Based on G189A, ESCM computes the transient performance of a Space Station atmospheric revitalization subsystem (ARS) with CO2 removal provided by a solid amine water desorbed subsystem called SAWD. Many performance parameters are computed some of which are cabin CO2 partial pressure, relative humidity, temperature, O2 partial pressure, and dew point. The program allows the user to simulate various possible combinations of man loading, metabolic profiles, cabin volumes and certain hypothesized failures that could occur.

Heat pipes for terrestrial applications in dehumidification systems

NASA Technical Reports Server (NTRS)

Khattar, Mukesh K.

1988-01-01

A novel application of heat pipes which greatly enhances dehumidification performance of air-conditioning systems is presented. When an air-to-air heat pipe heat exchanger is placed between the warm return air and cold supply air streams of an air conditioner, heat is efficiently transferred from the return air to the supply air. As the warm return air precools during this process, it moves closer to its dew-point temperature. Therefore, the cooling system works less to remove moisture. This paper discusses the concept, its benefits, the challenges of incorporating heat pipes in an air-conditioning system, and the preliminary results from a field demonstration of an industrial application.

Method of controlling scale in oil recovery operations

DOEpatents

Krajicek, Richard W.

1981-01-01

Disclosed is a method of producing highly viscous minerals from a subterranean formation by injection of an acidic, thermal vapor stream without substantial scale buildup in downstream piping, pumps and well bore. The process comprises heating the formation by injection of heat, preferably in the form of a thermal vapor stream composed of combustion gases and steam and injecting an acidic compound simultaneously with the thermal vapor stream into the formation at a temperature above the dew point of the thermal vapor stream. The acidic, thermal vapor stream increases the solubility of metal ions in connate water and thus reduces scaling in the downstream equipment during the production of viscous hydrocarbons.

Youngstown MAP, Ohio. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

DTIC Science & Technology

1982-05-10

Air Weather Service ( MAC ) SCuOL2., IL 6222 R- UmmRm m "PJ M MOP Fr 4 JUN SURFACE WEATHER OSVAIWJ YOUNGSTOWN MAP OH MC #725250 N 41 16 W 080 40 ELD...percentage frequency of distribution tables OHIO YOUNGSTIOWN M "P, OHIO 20. and dew point temperatures and relative humidity); and (F) Pressure Summnary...p.ouIwuIis P i o m Qm 1 ---- .0 YN - :, 7 -AL CLIMATOLO’Y RA"CH 7 .I*.T 7C WEATHER CONDITIONS .ATH’p SEPVICE/mAC CNIIN -, JN,.S7 %N MAP OH 73-81 A U G

Length-extension resonator as a force sensor for high-resolution frequency-modulation atomic force microscopy in air.

PubMed

Beyer, Hannes; Wagner, Tino; Stemmer, Andreas

2016-01-01

Frequency-modulation atomic force microscopy has turned into a well-established method to obtain atomic resolution on flat surfaces, but is often limited to ultra-high vacuum conditions and cryogenic temperatures. Measurements under ambient conditions are influenced by variations of the dew point and thin water layers present on practically every surface, complicating stable imaging with high resolution. We demonstrate high-resolution imaging in air using a length-extension resonator operating at small amplitudes. An additional slow feedback compensates for changes in the free resonance frequency, allowing stable imaging over a long period of time with changing environmental conditions.

Effect of climatological factors on respiratory syncytial virus epidemics

PubMed Central

NOYOLA, D. E.; MANDEVILLE, P. B.

2008-01-01

SUMMARY Respiratory syncytial virus (RSV) presents as yearly epidemics in temperate climates. We analysed the association of atmospheric conditions to RSV epidemics in San Luis Potosí, S.L.P., Mexico. The weekly number of RSV detections between October 2002 and May 2006 were correlated to ambient temperature, barometric pressure, relative humidity, vapour tension, dew point, precipitation, and hours of light using time-series and regression analyses. Of the variation in RSV cases, 49·8% was explained by the study variables. Of the explained variation in RSV cases, 32·5% was explained by the study week and 17·3% was explained by meteorological variables (average daily temperature, maximum daily temperature, temperature at 08:00 hours, and relative humidity at 08:00 hours). We concluded that atmospheric conditions, particularly temperature, partly explain the year to year variability in RSV activity. Identification of additional factors that affect RSV seasonality may help develop a model to predict the onset of RSV epidemics. PMID:18177520

Cape Canaveral, Florida range reference atmosphere 0-70 km altitude

NASA Technical Reports Server (NTRS)

Tingle, A. (Editor)

1983-01-01

The RRA contains tabulations for monthly and annual means, standard deviations, skewness coefficients for wind speed, pressure temperature, density, water vapor pressure, virtual temperature, dew-point temperature, and the means and standard deviations for the zonal and meridional wind components and the linear (product moment) correlation coefficient between the wind components. These statistical parameters are tabulated at the station elevation and at 1 km intervals from sea level to 30 km and at 2 km intervals from 30 to 90 km altitude. The wind statistics are given at approximately 10 m above the station elevations and at altitudes with respect to mean sea level thereafter. For those range sites without rocketsonde measurements, the RRAs terminate at 30 km altitude or they are extended, if required, when rocketsonde data from a nearby launch site are available. There are four sets of tables for each of the 12 monthly reference periods and the annual reference period.

The Effect of Deposit Temperature on the Catalytic SO2-to-SO3 Conversion in a Copper Flash Smelting Heat Recovery Boiler

NASA Astrophysics Data System (ADS)

Lehmusto, Juho; Vainio, Emil; Laurén, Tor; Lindgren, Mari

2018-02-01

The aim of the work was to study the catalytic role of copper flash smelter deposit in the SO2-to-SO3 conversion. In addition, the effect of process gas temperature at 548 K to 1173 K (275 °C to 900 °C) on the amount of SO3 formed was addressed both in the absence and presence of genuine copper flash smelter deposit. The SO3 conversion rate changed as a function of process gas temperature, peaking at 1023 K (750 °C). A dramatic increase in the SO2-to-SO3 conversion was observed when process dust was present, clearly indicating that process dust catalyzes the SO2-to-SO3 conversion. Based on these results, the catalytic ability of the deposit may lead to sulfuric acid dew point corrosion.

How Different are SMOS Morning and Evening Observations?

NASA Astrophysics Data System (ADS)

Rowlandson, T. L.; Hornbuckle, B. K.

2010-12-01

The Soil Moisture Ocean Salinity (SMOS) satellite was launched by the European Space Agency in November, 2009, to make measurements of soil moisture at L-band in a 40 km x 40 km footprint, making passes over the north central region of the United States at 6am and 6pm approximately, with the intent of having passes at least every 3 days. No comparisons between 6am and 6pm have been made. The NASA Soil Moisture Active Passive (SMAP) intends to use only 6am data because of concerns of the quality of the data for 6pm passes. Brightness temperature outputs of the SMOS data were examined for both the 6am and 6pm passes to determine if changes in measurement exist for days when there is no rainfall. Changes in the brightness temperature can result from changes in internal water content of the crop, which we currently do not have the ability to accurately determine, presence of external water on the canopy, which in this study will be limited to dew, changes in canopy and soil temperature, and changes in soil moisture. The first step taken in this project was to investigating changes between the 6am and 6pm measurements that may result from the presence of dew on the canopy. Land and airborne L-band radiometers have shown that dew on a crop canopy provides a source of error in the measurements of surface soil moisture. The magnitude and sign of the error appears to be crop dependent. The empirical model of RH>90% has been used extensively to simulate dew duration. At the Iowa Validation site in Ames, Iowa, relative humidity was measured above the crop canopy, in both corn and soybeans, and within the crop canopy. Comparisons were made between the relative humidity measured above the canopy to that measured within the canopy at 3 locations within the field. These values were also compared to relative humidity measured at a standard weather station near the field site. These measurements were used to define a more appropriate relative humidity threshold for the central Midwest, specifically where agriculture is a dominant land use. It is important that relative humidity data utilized from a source outside of an agricultural field is representative of the conditions occurring within the crop canopy, which is generally higher. SMOS pixels were chosen for regions where > 75% of the land area was comprised of agriculture. Days were chosen where there was a satellite pass both at 6am and 6pm, on days when no rainfall occurred. As such, changes in soil moisture would be minimal. The brightness temperatures obtained were normalized using the polarization index, which uses both v-pol and h-pol outputs to remove the influence of changes in surface temperature on the brightness temperature. As such, changes in the brightness temperature can be attributed to changes in the water content of the crop canopy or the presence of dew. Identifying changes in the signal between morning and evening passes will aid in determining if the presence of dew on crop canopy is an important source of error in soil moisture measurements at L-band, and more importantly, if 6pm measurements appear to be viable for soil moisture retrieval.

AqSo_NaCl: Computer program to calculate p-T-V-x properties in the H2O-NaCl fluid system applied to fluid inclusion research and pore fluid calculation

NASA Astrophysics Data System (ADS)

Bakker, Ronald J.

2018-06-01

The program AqSo_NaCl has been developed to calculate pressure - molar volume - temperature - composition (p-V-T-x) properties, enthalpy, and heat capacity of the binary H2O-NaCl system. The algorithms are designed in BASIC within the Xojo programming environment, and can be operated as stand-alone project with Macintosh-, Windows-, and Unix-based operating systems. A series of ten self-instructive interfaces (modules) are developed to calculate fluid inclusion properties and pore fluid properties. The modules may be used to calculate properties of pure NaCl, the halite-liquidus, the halite-vapourus, dew-point and bubble-point curves (liquid-vapour), critical point, and SLV solid-liquid-vapour curves at temperatures above 0.1 °C (with halite) and below 0.1 °C (with ice or hydrohalite). Isochores of homogeneous fluids and unmixed fluids in a closed system can be calculated and exported to a.txt file. Isochores calculated for fluid inclusions can be corrected according to the volumetric properties of quartz. Microthermometric data, i.e. dissolution temperatures and homogenization temperatures, can be used to calculated bulk fluid properties of fluid inclusions. Alternatively, in the absence of total homogenization temperature the volume fraction of the liquid phase in fluid inclusions can be used to obtain bulk properties.

Wet atmospheric generation apparatus

NASA Technical Reports Server (NTRS)

Hamner, Richard M. (Inventor); Allen, Janice K. (Inventor)

1990-01-01

The invention described relates to an apparatus for providing a selectively humidified gas to a camera canister containing cameras and film used in space. A source of pressurized gas (leak test gas or motive gas) is selected by a valve, regulated to a desired pressure by a regulator, and routed through an ejector (venturi device). A regulated source of water vapor in the form of steam from a heated reservoir is coupled to a low pressure region of the ejector which mixes with high velocity gas flow through the ejector. This mixture is sampled by a dew point sensor to obtain dew point thereof (ratio of water vapor to gas) and the apparatus adjusted by varying gas pressure or water vapor to provide a mixture at a connector having selected humidity content.

Cryogenic Blackbody-Radiation Calibration Source

NASA Technical Reports Server (NTRS)

Burkett, Cecil G., Jr.; Daryabeigi, Kamran

1993-01-01

Operating temperatures range from ambient down to minus 100 degrees C. V-grooved front face of source body blackened and recessed in black sleeve. Semiairtight chamber that houses source purged with dry nitrogen gas to prevent formation of dew or frost at low operating temperature.

[Examination of upper airway function using the dew point hygrometer with semiconductor detector].

PubMed

Weremczuk, Jerzy; Paczesny, Daniel; Rapiejko, Piotr; Jachowicz, Ryszard; Jurkiewicz, Dariusz

2005-09-01

The nasal mucosa with blood capillary network has a remarkable role in respiration process. The most important nose functions are heating and humidifying to optimal level of reaching throat and lungs air and partly absorption of humidity and temperature from expired air. Variations of humidifying and heating processes can invoke some upper airways disorders. The paper presents dew point hygrometer which was specially design for laryngological purposes. The hygrometer can measure dynamic changes of humidity in upper airways. The device is fully automated, easy to operate and can communicate with external personal computer. Database application allows saving patient data with archive examination results and can display them easily. During ongoing clinical tests, still increasing amount of data will allow precisely investigate correlations between humidifying process and some diseases. The main advantage of the device is a short response time on humidity changing. The number of readings (detections) can reach 5 readings per second (slightly depending on humidity level) which is much faster than in available on the market hygrometers with sorption sensors. The paper also presents some results obtained in group of healthy volunteers and one patient with tracheostomy The tests figured out actual humidity in certain parts of upper airways: nose, throat, trachea in breathing cycles under various surrounding conditions. The constructed hygrometer can be used for air humidity measurement in upper airways during some diseases and for evaluation of an influence of some drugs and environmental conditions changing on air upper ways mucosa.

Storage stability of a commercial hen egg yolk powder in dry and intermediate-moisture food matrices.

PubMed

Rao, Qinchun; Fisher, Mary Catherine; Guo, Mufan; Labuza, Theodore P

2013-09-11

Quality loss in intermediate-moisture foods (IMF) such as high-protein nutrition bars (HPNB) in the form of hardening, nonenzymatic browning, and free amino group loss is a general concern for the manufacturers. To measure the extent of quality loss over time in terms of these negative attributes, through changing the ratio by weight between two commercial spray-dried hen egg powders, egg white (DEW) and egg yolk (DEY), the storage stability of 10 IMF systems (water activity (aw) ∼ 0.6) containing 5% glycerol, 10% shortening, 35% protein, and 50% sweetener (either maltitol or 50% high-fructose corn syrup/50% corn syrup (HFCS/CS)) were studied. Additionally, the storage stability of the DEY powder itself was investigated. Overall, during storage at different temperatures (23, 35, and 45 °C), the storage stability of DEY in dry and IMF matrices was mainly controlled by the coaction of three chemical reactions (disulfide bond interaction, Maillard reaction, and lipid oxidation). The results showed that by replacing 25% of DEW in an IMF model system with DEY, the rate of bar hardening was significantly lower than that of the models with only DEW at all temperatures due to the softening effect of the fat in DEY. Furthermore, the use of maltitol instead of HFCS/CS in all bar systems not only resulted in decreased hardness but also drastically decreased the change in the total color difference (ΔE*). Interestingly, there was no significant loss of free amino groups in the maltitol systems at any DEW/DEY ratio.

Fog-drip contributions to soil moisture as determined through passive fog collector measurements, leaf wetness data, and soil moisture at Pepperwood Preserve, Sonoma County, California.

NASA Astrophysics Data System (ADS)

Micheli, L.; Dodge, C.; Fernandez, D.; Weiss, P. L.; Flint, L. E.; Flint, A. L.; Torregrosa, A.

2016-12-01

Summertime coastal fog advects from the ocean and transports water inland in the form of fog droplets to forests and grasslands. The amount of fog water delivered to the soil through fog drip from foliage and other surfaces that have captured and accumulated the droplets is often difficult to quantify due to many challenges including the difficulty of measuring the relatively small variations in soil moisture that accompany fog events. This study details summer season records collected from 4 sites at the Pepperwood Preserve in Santa Rosa, CA. Fog drip volumes were measured using 1 m2 standard fog collectors located at a grassland site for the past three summers. Soil moisture measurements were collected for portions of the three summer seasons from three sites: two oak woodland understory sites and a grassland site on the edge of a forest. One oak woodland site was within 400 m of the standard fog collector grassland site. Leaf wetness sensors (LWS) were co-located at all soil moisture sites. We observe a much higher frequency of wet periods at the grassland site than at the nearby oak woodland site during the summer fog season. One hypothesis is that the oak canopy acts to protect the LWS at the oak woodland site from nocturnal radiative cooling, thereby reducing condensation and dew formation. Another hypothesis is that the oak woodland canopy tends sheltered the understory during light fog events, resulting in edge effects that may tend to reduce fog deposition within the canopy. Leaf and soil moisture measurements both during fog events and during periods without fog but when dew point is reached may provide a more complete picture of non-rain mechanisms of moisture delivery to the foliage and the soil. Investigations are on-going to include corresponding meteorological data (wind speed and direction, relative humidity and temperature) to understand relative contributions to the soil associated with both fog and dew and to better distinguish between fog and dew inputs.

Counter flow cooling drier with integrated heat recovery

DOEpatents

Shivvers, Steve D [Prole, IA

2009-08-18

A drier apparatus for removing water or other liquids from various materials includes a mixer, drying chamber, separator and regenerator and a method for use of the apparatus. The material to be dried is mixed with a heated media to form a mixture which then passes through the chamber. While passing through the chamber, a comparatively cool fluid is passed counter current through the mixture so that the mixture becomes cooler and drier and the fluid becomes hotter and more saturated with moisture. The mixture is then separated into drier material and media. The media is transferred to the regenerator and heated therein by the hot fluid from the chamber and supplemental heat is supplied to bring the media to a preselected temperature for mixing with the incoming material to be dried. In a closed loop embodiment of the apparatus, the fluid is also recycled from the regenerator to the chamber and a chiller is utilized to reduce the temperature of the fluid to a preselected temperature and dew point temperature.

MLITemp: A computer program to predict the thermal effects associated with hypervelocity impact damage to space station MLI

NASA Technical Reports Server (NTRS)

Rule, W. K.; Giridharan, V.

1991-01-01

A family of user-friendly, DOS PC based, Microsoft BASIC programs written to provide spacecraft designers with empirical predictions of space debris damage to orbiting spacecraft are described. Spacecraft wall temperatures and condensate formation is also predicted. The spacecraft wall configuration is assumed to consist of multilayered insulation (MLI) placed between a Whipple style bumper and the pressure wall. Impact damage predictions are based on data sets of experimental results obtained from simulating debris impacts on spacecraft using light gas guns on earth. A module of the program facilitates the creation of the database of experimental results that is used by the damage prediction modules to predict damage to the bumper, the MLI, and the pressure wall. A finite difference technique is used to predict temperature distributions in the pressure wall, the MLI, and the bumper. Condensate layer thickness is predicted for the case where the pressure wall temperature drops below the dew point temperature of the spacecraft atmosphere.

Cooling towers, the neglected energy conservations and money making machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, R.

1996-12-31

The heat Rejection Industry defines a nominal cooling tower as circulating three gallons of water per minute (GPM) per ton of refrigeration from entering the tower at 95 {degrees}F, Hot Water temperature (HWT), Leaving at 85{degrees}F Cold Water Temperature (CWT) at a Design Wet Bulb of 70{degrees}F (WBT). Manufacturers then provide a selection chart based on various wet bulb temperatures and HWTs. The wet bulb fluctuates and varies throughout the world since it is the combination ambient temperature, relative humidity, and/or dew point. Different HWT and CWT requirements are usually charted as they change, so that the user can selectmore » the nominal cooling tower model recommended by the manufacturer. In the specification of cooling towers it is necessary to clearly understand the definition of nominal cooling tower, and to make sure the specification you need addressed can be met by the system you purchase. This should be tested prior to final acceptance.« less

Distribution of the Mosquito Communities (Diptera: Culicidae) in Oviposition Traps Introduced into the Atlantic Forest in the State of Rio de Janeiro, Brazil.

PubMed

Silva, Shayenne Olsson Freitas; Ferreira de Mello, Cecilia; Figueiró, Ronaldo; de Aguiar Maia, Daniele; Alencar, Jeronimo

2018-04-01

The Atlantic Rainforest of South America is one of the major biodiversity hotspots of the world and serves as a place of residence for a wide variety of Culicidae species. Mosquito studies in the natural environment are of considerable importance because of their role in transmitting pathogens to both humans and other vertebrates. Community diversity can have significant effects on the risk of their disease transmission. The objective of this study was to understand the distribution of mosquito communities using oviposition traps in a region of the Atlantic Forest. Sampling was carried out in Bom Retiro Private Natural Reserve (RPPNBR), located in Casimiro de Abreu, Rio de Janeiro, using oviposition traps, which were set in the forest environment, from October 2015 to December 2016. The canonical correspondence analysis was used to assess the influence of the climatic variables (precipitation, maximum dew point, and direction) throughout the seasons on the population density of the mosquito species. The results showed that population density was directly influenced by climatic variables, which acted as a limiting factor for the mosquito species studied. The climatic variables that were significantly correlated with the density of the mosquito species were precipitation, maximum dew point, and direction. Haemagogus janthinomys was positively correlated with the three climatic variables, whereas Haemagogus leucocelaenus was positively correlated with precipitation and maximum dew point, and negatively correlated with direction.

A dryer for rapid response on-line expired gas measurements.

PubMed

Deno, N S; Kamon, E

1979-06-01

A dryer is described for use in on-line breath-by-breath gas analysis systems. The dryer continuously removes water vapor by condensation and controls the sample gas at 2 degrees C dew-point temperature or 5 Torr water vapor partial pressure. It is designed to operate at gas sampling flow rates from 0.5 to 1 1.min-1. The step-response time for the described system including a Beckman LB-2 CO2 analyzer, sampling tubing, and dryer is 120 ms at 1 l.min-1. The time required for gas samples to transport through the dryer is 105 ms at a gas sampling-flow rate of 1 l.min=1.

Influence of epidemiological factors on the bioherbicidal efficacy of a Xanthomonas capestris isolate on common cocklebur (Xanthium strumarium)

USDA-ARS?s Scientific Manuscript database

Greenhouse and controlled-environment studies were conducted to determine the effects of incubation temperature, dew period temperature and duration, plant growth stage, and cell concentration on the bioherbicidal efficacy of a highly virulent isolate (LVA987) of the bacterial pathogen, Xanthomonas ...

Effects of environmental factors on monuments: the Harkhuf Tomb in Aswan, Egypt

NASA Astrophysics Data System (ADS)

Baldi, Marina

2015-04-01

The tombs of the nobles excavated in the rocks on the Nile west bank at Qubbet el-Hawa in Aswan (Egypt) testify the role of the city as the southern gate of Egypt. In old times Aswan was the starting point of caravans travelling far south in uncovered territories and bringing back precious and exotic goods. Inscriptions on the tombs reflect the explorations and trades of that time and the cultural exchanges with southern territories. Nowadays the tombs, exposed to the environmental factors - wind, sun, rainfall - and to air polluttants originated from the town of Aswan are under a fast deterioration process. It is therefore necessary a full documentation of the tombs and of their façade and a study of the deterioration process due to the impact of the environmental factors. As a case study the tomb of Harkhuf at Qubbet el-Hawa has been chosen, because of its importance, its status of decay, and for the old documentation by the Italian Egyptologist E. Schiaparelli. The climate factors affecting the tomb of Harkhuf are air temperature, its diurnal excursion, and wind, and, at some extent, relative humidity. In fact, in Aswan, night time Humidity can be more than 30% during the winter months, while precipitation is a very rare event occurring once every 1 or 2 years, but has important impact due to its high intensity and short duration with devastating impact on manufact and structures in the area. The experiment, designed using portable meteorological instruments, permitted to define if the microclimate near the Harkhuf Tomb has the same characteristics of the larger Aswan area which can be derived by the meteorological station located at the Aswan airport. However differences in the microclimate are evident and preliminary analysis of data collected between 8:00 am and 4:00 pm during some consecutive days will be presented. The study permitted to identify and measure the differential heating of the façade, with the right part reaching temperatures much warmer than the left and for a longer period, being under the direct sunrays for a longer period. In the interior, during the day, the temperature excursion is much more moderate, but some dew formation has been observed which contributes to the mold formation in parts of the walls of the tumb. In addition, some measurements of wind intensity and direction show a persistent wind blowing from N-NE starting mid-morning, around 10:30 am until late afternoon. In particular, the observations permitted: > to understand if the different parts of the façade of the tomb are under the influence of physical stress of different intensity due to the temperature gradient detected along the façade itself; > to determine if and in which conditions the temperatures excursion together with the right level of relative humidity of the air favor the formation of dew at dawn and of high dew point values. This study is part of the multidisciplinary project TECH (Technologies for the Egyptian Cultural Heritage) funded by the National Reserach Council of Italy and by the Academy of Scientific Research and Technology of Egypt (ASRT).

The change of steel surface chemistry regarding oxygen partial pressure and dew point

NASA Astrophysics Data System (ADS)

Norden, Martin; Blumenau, Marc; Wuttke, Thiemo; Peters, Klaus-Josef

2013-04-01

By investigating the surface state of a Ti-IF, TiNb-IF and a MnCr-DP after several series of intercritical annealing, the impact of the annealing gas composition on the selective oxidation process is discussed. On behalf of the presented results, it can be concluded that not the general oxygen partial pressure in the annealing furnace, which is a result of the equilibrium reaction of water and hydrogen, is the main driving force for the selective oxidation process. It is shown that the amounts of adsorbed gases at the strip surface and the effective oxygen partial pressure resulting from the adsorbed gases, which is mainly dependent on the water content of the annealing furnace, is driving the selective oxidation processes occurring during intercritical annealing. Thus it is concluded, that for industrial applications the dew point must be the key parameter value for process control.

Viking Lander: subsurface water analyzing probe. [Mars subsoil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, G.J.

1969-10-01

A small terradynamic (soil penetrating) vehicle, to be released from the Viking Lander at an altitude of between 5000 and 6000 feet before the terminal descent on the vernier rockets begins, will implant a sensor package 3 to 5 feet beneath the surface to measure water content of Mars subsoil. As it penetrates the soil, the vehicle separates into a probe which carries the primary instrumentation and a tail section which contains the power supply, secondary sensors, and transmitter and antenna assembly. The two sections remain linked by a hard wire umbilical which provides for power and data flow betweenmore » the sections. After impact, a soil moisture subsystem would be activated to gather approximately 100 milligrams of soil at the depth of the penetrating probe. After the mass of the sample is measured, its water content would be determined by heating in a sealed known volume and measuring the dew point of the resulting water vapor with a specular reflection dew point indicator. The penetrating probe and the tail section each contain a pair of aluminum oxide hygrometer elements and one sensistor temperature sensor which, on request by an on-board programmer will measure temperature and absolute water content of the vapor phase in equilibrium with the surrounding soil. Once each 8 hours, the digitized output of the sensors would be transmitted by the RF link to the Lander. This apparatus is expected to measure the water vapor in equilibrium with the soil water in concentrations as low as 0.01 microgram per liter at --60/sup 0/C and absolute soil water in amounts as small as 10 micrograms per gram of soil. A radioisotope power supply would provide an expected life for this instrumentation package in excess of the proposed 90-day mission for the Mars Viking Lander.« less

Advancements in water vapor electrolysis technology. [for Space Station ECLSS

NASA Technical Reports Server (NTRS)

Chullen, Cinda; Heppner, Dennis B.; Sudar, Martin

1988-01-01

The paper describes a technology development program whose goal is to develop water vapor electrolysis (WVE) hardware that can be used selectively as localized topping capability in areas of high metabolic activity without oversizing the central air revitalization system on long-duration manned space missions. The WVE will be used primarily to generate O2 for the crew cabin but also to provide partial humidity control by removing water vapor from the cabin atmosphere. The electrochemically based WVE interfaces with cabin air which is controlled in the following ranges: dry bulb temperature of 292 to 300 K; dew point temperature of 278 to 289 K; relative humidity of 25 to 75 percent; and pressure of 101 + or - 1.4 kPa. Design requirements, construction details, and results for both single-cell and multicell module testing are presented, and the preliminary sizing of a multiperson subsystem is discussed.

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

NASA Astrophysics Data System (ADS)

Santoro, G. J.; Gokoglu, S. A.; Kohl, F. J.; Stearns, C. A.; Rosner, D. E.

The mechanism of deposition of Na2SO4 was studied under controlled laboratory conditions and the results have been compared to a recently developed comprehensive theory of vapor deposition. Thus Na2SO4, NaCl, NaNO3 and simulated sea salt solutions were injected into the combustor of a nominal Mach 0.3 burner rig burning jet fuel at constant fuel/air ratios. The deposits formed on inert collectors, rotation in the cross flow of the combustion gases, were weighed and analyzed. Collector temperature was uniform and could be varied over a large range by internal air cooling. Deposition rates and dew point temperatures were determined. Supplemental testing included droplet size measurements of the atomized salt solutions. These tests along with thermodynamic and transport calculations were utilized in the interpretation of the deposition results.

Deposition of Na2SO4 from salt-seeded combustion gases of a high velocity burner rig

NASA Technical Reports Server (NTRS)

Santoro, G. J.; Gokoglu, S. A.; Kohl, F. J.; Stearns, C. A.; Rosner, D. E.

1984-01-01

The mechanism of deposition of Na2SO4 was studied under controlled laboratory conditions and the results have been compared to a recently developed comprehensive theory of vapor deposition. Thus Na2SO4, NaCl, NaNO3 and simulated sea salt solutions were injected into the combustor of a nominal Mach 0.3 burner rig burning jet fuel at constant fuel/air ratios. The deposits formed on inert collectors, rotation in the cross flow of the combustion gases, were weighed and analyzed. Collector temperature was uniform and could be varied over a large range by internal air cooling. Deposition rates and dew point temperatures were determined. Supplemental testing included droplet size measurements of the atomized salt solutions. These tests along with thermodynamic and transport calculations were utilized in the interpretation of the deposition results.

Hybrid air revitalization system for a closed ecosystem

NASA Technical Reports Server (NTRS)

Lee, M. G.; Brown, Mariann F.

1990-01-01

An air-revitalization concept is presented with experimental results to assess the practicality and applicability of the proposed system to extended-duration manned missions. The Hybrid Air Revitalization System (HARS) uses plants in a habitat to remove metabolic CO2 and moisture and produce oxygen and food. CO2 and O2 partial pressures, temperature, and humidity are regulated by means of electrochemical CO2 and O2 chemical separators and a moisture condenser separator. A cell-test facility is described in which the electrochemical CO2 removal processes are investigated with and without using H2. Performance is optimized by using 25-30 percent Teflon in the gas-diffusion-type electrode, employing a thin electrolyte matrix, operating at higher temperatures and lower dew points. The HARS concept is found to be a feasible approach to the electrochemical separation of CO2 and O2.

[Moisture and mold on the inner walls of prefabricated building slabs--investigating a strange cause].

PubMed

Kaufhold, T; Fiedler, K; Jung, G; Lindner, M; Gassel, R P

1997-04-01

Reasons for indoor-moisture beyond the normal level can be caused by penetrating dampness, condensation-water, and apartment misuse. A fall in the air temperature below the dew point in connection with moulding inside buildings becomes evident mostly at places like badly insulated outer-walls or room-corners. In a number of houses built between 1980 and 1983 in the so called "Plattenbauweise" (prefabricated slabs), exclusively the inner-walls were covered in mould around cracks in the walls. Examinations showed connections between the apartment and the outer-corridor with a slight exchange of air through the cracks. Warm, wet air escaped from the apartment into the outer-corridor, and cold air entered the apartment from the outer-corridor. This temporary fall below the dewpoint caused by suitable variation of temperature probably resulted in the building materials and wallpapers becoming damp, as well as the growth of mould.

Developing a predictive tropospheric ozone model for Tabriz

NASA Astrophysics Data System (ADS)

Khatibi, Rahman; Naghipour, Leila; Ghorbani, Mohammad A.; Smith, Michael S.; Karimi, Vahid; Farhoudi, Reza; Delafrouz, Hadi; Arvanaghi, Hadi

2013-04-01

Predictive ozone models are becoming indispensable tools by providing a capability for pollution alerts to serve people who are vulnerable to the risks. We have developed a tropospheric ozone prediction capability for Tabriz, Iran, by using the following five modeling strategies: three regression-type methods: Multiple Linear Regression (MLR), Artificial Neural Networks (ANNs), and Gene Expression Programming (GEP); and two auto-regression-type models: Nonlinear Local Prediction (NLP) to implement chaos theory and Auto-Regressive Integrated Moving Average (ARIMA) models. The regression-type modeling strategies explain the data in terms of: temperature, solar radiation, dew point temperature, and wind speed, by regressing present ozone values to their past values. The ozone time series are available at various time intervals, including hourly intervals, from August 2010 to March 2011. The results for MLR, ANN and GEP models are not overly good but those produced by NLP and ARIMA are promising for the establishing a forecasting capability.

The effects of trace impurities in coal-derived liquid fuels on deposition and accelerated high temperature corrosion of cast superalloys

NASA Technical Reports Server (NTRS)

Lowell, C. E.; Deadmore, D. J.; Santoro, G. J.; Kohl, F. J.

1981-01-01

The effects of trace metal impurities in coal-derived liquids on deposition, high temperature corrosion and fouling were examined. Alloys were burner rig tested from 800 to 1100 C and corrosion was evaluated as a function of potential impurities. Actual and doped fuel test were used to define an empirical life prediction equation. An evaluation of inhibitors to reduce or eliminate accelerated corrosion was made. Barium and strontium were found to limit attack. Intermittent application of the inhibitors or silicon additions were found to be effective techniques for controlling deposition without losing the inhibitor benefits. A computer program was used to predict the dew points and compositions of deposits. These predictions were confirmed in deposition test. The potential for such deposits to plug cooling holes of turbine airfoils was evaluated. Tests indicated that, while a potential problem exists, it strongly depended on minor impurity variations.

Design, fabrication and delivery of a prototype saturator for ACPL

NASA Technical Reports Server (NTRS)

Keyser, G.; Rogers, C. F.; Squires, P.

1979-01-01

The design configuration and performance characteristics of a saturator developed to provide ground-based simulation for some of the experiments for ACPL-1 first flights of Spacelab are described, some difficulties encountered with the apparatus are discussed, and recommendations concerning testing of this type of instrument are presented. The saturators provide a means of accurately fixing the water vapor mixing ratio of an aerosol sample. Dew point temperatures from almost freezing to ambient room temperatures can be attained with high precision. The instruments can accommodate aerosol flow rates approaching 1000 cc/s. Provisions were made to inject aerosols upstream of these saturators, although downstream injection can be accomplished as well. A device of this type will be used in the ACPL-1 to condition various aerosols delivered concurrently to a CFD, expansion chamber, and static diffusion chamber used in zero gravity cloud-forming experiments. The saturator was designed to meet the requirements projected for the flight instrument.

Efficiency analysis of semi-open sorption heat pump systems

DOE PAGES

Gluesenkamp, Kyle R.; Chugh, Devesh; Abdelaziz, Omar; ...

2016-08-10

Sorption systems traditionally fall into two categories: closed (heat pumps and chillers) and open (dehumidification). Recent work has explored the possibility of semi-open systems, which can perform heat pumping or chilling while utilizing ambient humidity as the working fluid of the cycle, and are still capable of being driven by solar, waste, or combustion heat sources. The efficiencies of closed and open systems are well characterized, and can typically be determined from four temperature s. In this work, the performance potential of semi-open systems is explored by adapting expressions for the efficiency of closed and open systems to the novelmore » semi-open systems. A key new parameter is introduced, which involves five temperatures, since both the ambient dry bulb and ambient dew point are used. Furthermore, this additional temperature is necessary to capture the open absorber performance in terms of both the absorption of humidity and sensible heat transfer with surrounding air.« less

Engineering evaluation of the use of the Timberline condensing economizer for particulate collection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butcher, T.; Serry, H.

1980-12-01

The possible use of the Timberline Industries condensing economizer as a particulate collection device on commercial sector boilers which are being converted to coal-oil mixture (COM) firing has been considered. The saturation temperature of the water vapor in the flue gas has been estimated as a function of excess air and ambient relative humidity. Also, boiler stack losses have been estimated for a variety of operating conditions including stack temperatures below the dew point. The condensing economizer concept will be limited to applications which can use the low temperature heat including water heating and forced air space heating. The potentialmore » particulate collection efficiency, water disposal, and similar heat recovery devices are discussed. A cost analysis is presented which indicates that the economizer system is not competitive with a cyclone but is competitive with a baghouse. The use of the cyclone is limited by collection efficiency. The measurement of COM flyash particle size distribution is recommended.« less

Efficiency analysis of semi-open sorption heat pump systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gluesenkamp, Kyle R.; Chugh, Devesh; Abdelaziz, Omar

Sorption systems traditionally fall into two categories: closed (heat pumps and chillers) and open (dehumidification). Recent work has explored the possibility of semi-open systems, which can perform heat pumping or chilling while utilizing ambient humidity as the working fluid of the cycle, and are still capable of being driven by solar, waste, or combustion heat sources. The efficiencies of closed and open systems are well characterized, and can typically be determined from four temperature s. In this work, the performance potential of semi-open systems is explored by adapting expressions for the efficiency of closed and open systems to the novelmore » semi-open systems. A key new parameter is introduced, which involves five temperatures, since both the ambient dry bulb and ambient dew point are used. Furthermore, this additional temperature is necessary to capture the open absorber performance in terms of both the absorption of humidity and sensible heat transfer with surrounding air.« less

Characterization of convection-related parameters by Raman lidar: Selected case studies from the convective and orographically-induced precipitation study

NASA Astrophysics Data System (ADS)

Di Girolamo, Paolo; Summa, Donato; Stelitano, Dario

2013-05-01

An approach to determine the convective available potential energy (CAPE) and the convective inhibition (CIN) based on the use of data from a Raman lidar system is illustrated in this work. The use of Raman lidar data allows to provide high temporal resolution measurements (5 min) of CAPE and CIN and follow their evolution over extended time periods covering the full cycle of convective activity. Lidar-based measurements of CAPE and CIN are obtained from Raman lidar measurements of the temperature and water vapor mixing ratio profiles and the surface measurements of temperature, pressure and dew point temperature provided by a surface weather station. The approach is applied to the data collected by the Raman lidar system BASIL in the frame of COPS. Attention was focused on 15 July and 25-26 July 2007. Lidar-based measurements are in good agreement with simultaneous measurements from radiosondes and with estimates from different mesoscale models.

[Comparison of ability to humidification of inspired air through the nose and oral cavity using dew point hygrometer].

PubMed

Paczesny, Daniel; Rapiejko, Piotr; Weremczuk, Jerzy; Jachowicz, Ryszard; Jurkiewicz, Dariusz

2007-01-01

Aim of this study was to check at the hospital the dew point hygrometer for fast measurement of air humidity in upper airways. The nose ability to humidification of inspired air and partially recover moisture from expired air was evaluated. Measurements from respiration through the nose and oral cavity were compared. The study was carried out in a group of 30 people (8 female and 22 male), age group 18 to 70 (mean age: 37 years old). In 22 of the participants there were no deviation from normal state in laryngologic examination, while in 4 participants nasal septum deviation without imaired nasal; oatency was found, in other 3--nasal vonchae hyperthrophy and in 1--nasal polips (grade I). The measurements of air humidity in upper air ways was done using specially designed and constructed measurement system. The air inspired through the nose and oral cavity is humidified. For typical external conditions (T = 22 degrees C i RH = 50%) the nose humidifies inspired air two times better then oral cavity (short time range of measurement approximately 1 min). Moisture from expired air through the nose is partially recovered (for patients with regular patency is 25% of the value of humidifying of inspired air). The oral cavity does not have ability to partially recovery moisture form expired air. The paper presented fast dew point hygrometer based on semiconductor microsystems for measurement humidity in inspired and expired air through the nose and oral cavity. Presented system can be a proper instrument for evaluation of nasal functions.

Water vapor measurement system in global atmospheric sampling program, appendix

NASA Technical Reports Server (NTRS)

Englund, D. R.; Dudzinski, T. J.

1982-01-01

The water vapor measurement system used in the NASA Global Atmospheric Sampling Program (GASP) is described. The system used a modified version of a commercially available dew/frostpoint hygrometer with a thermoelectrically cooled mirror sensor. The modifications extended the range of the hygrometer to enable air sample measurements with frostpoint temperatures down to -80 C at altitudes of 6 to 13 km. Other modifications were made to permit automatic, unattended operation in an aircraft environment. This report described the hygrometer, its integration with the GASP system, its calibration, and operational aspects including measurement errors. The estimated uncertainty of the dew/frostpoint measurements was + or - 1.7 Celsius.

Chemical composition of dew in Amman, Jordan

NASA Astrophysics Data System (ADS)

Jiries, Anwar

Twenty-six dew samples were collected on a glass surface from an urbanized area in Amman city during the period October 1999 to June 2000. They were analyzed for the major ions (Cl, SO 4, NO 3, Ca, Mg, Na, K and NH 4) in addition to three heavy metals (Pb, Cd and Co). Rain samples were collected for the same period and compared to the chemical constituents of dew. It was found that both rain and dew samples were of almost neutral acidity due to the buffering effect of CaCO 3. Dew composition was mainly from CaSO 4 solution due to conversion of CaCO 3 to CaSO 4 when left exposed to a sulfate-rich atmosphere. The total dissolved solids were higher in dew than rain samples of the same period. This was attributed to higher evaporation effect on dew than rain. The heavy metal content in dew is highest during the cold winter season (December-March) due to excess fossil fuel combustion for heating purposes in this period. The heavy metal content in dew was lower than that for rain during the same period because of the shorter period of dew formation than rainwater.

Electronic leaf wetness duration sensor: why it should be painted.

PubMed

Sentelhas, P C; Monteiro, J E B A; Gillespie, T J

2004-05-01

The purpose of this study was to compare and evaluate the performance of electronic leaf wetness duration (LWD) sensors in measuring LWD in a cotton crop canopy when unpainted and painted sensors were used. LWD was measured with flat, printed-circuit wetness sensors, and the data were divided into two periods of 24 days: from 18 December 2001 to 10 January 2002, when the sensors were unpainted, and from 20 January to 13 February 2002, when the sensors were painted with white latex paint (two coats of paint). The data analysis included evaluating the coefficient of variation (CV%) among the six sensors for each day, and the relationship between the measured LWD (mean for the six sensors) and the number of hours with dew point depression under 2 degrees C, used as an indicator of dew presence. The results showed that the painting markedly reduced the CV% values. For the unpainted sensors the CV% was on average 67% against 9% for painted sensors. For the days without rainfall this reduction was greater. Comparing the sensor measurements to another estimator of LWD, in this case the number of hours with dew point depression under 2 degrees C, it was also observed that painting improved not only the precision of the sensors but also their sensitivity, because it increases the ability of the sensor to detect and measure the wetness promoted by small water droplets.

Vapor-screen technique for flow visualization in the Langley Unitary Plan Wind Tunnel

NASA Technical Reports Server (NTRS)

Morris, O. A.; Corlett, W. A.; Wassum, D. L.; Babb, C. D.

1985-01-01

The vapor-screen technique for flow visualization, as developed for the Langley Unitary Plan Wind Tunnel, is described with evaluations of light sources and photographic equipment. Test parameters including dew point, pressure, and temperature were varied to determine optimum conditions for obtaining high-quality vapor-screen photographs. The investigation was conducted in the supersonic speed range for Mach numbers from 1.47 to 4.63 at model angles of attack up to 35 deg. Vapor-screen photographs illustrating various flow patterns are presented for several missile and aircraft configurations. Examples of vapor-screen results that have contributed to the understanding of complex flow fields and provided a basis for the development of theoretical codes are presented with reference to other research.

Analysis of a resistance-energy balance method for estimating daily evaporation from wheat plots using one-time-of-day infrared temperature observations

NASA Technical Reports Server (NTRS)

Choudhury, B. J.; Idso, S. B.; Reginato, R. J.

1986-01-01

Accurate estimates of evaporation over field-scale or larger areas are needed in hydrologic studies, irrigation scheduling, and meteorology. Remotely sensed surface temperature might be used in a model to calculate evaporation. A resistance-energy balance model, which combines an energy balance equation, the Penman-Monteith (1981) evaporation equation, and van den Honert's (1948) equation for water extraction by plant roots, is analyzed for estimating daily evaporation from wheat using postnoon canopy temperature measurements. Additional data requirements are half-hourly averages of solar radiation, air and dew point temperatures, and wind speed, along with reasonable estimates of canopy emissivity, albedo, height, and leaf area index. Evaporation fluxes were measured in the field by precision weighing lysimeters for well-watered and water-stressed wheat. Errors in computed daily evaporation were generally less than 10 percent, while errors in cumulative evaporation for 10 clear sky days were less than 5 percent for both well-watered and water-stressed wheat. Some results from sensitivity analysis of the model are also given.

Modeling Radiation Fog

NASA Astrophysics Data System (ADS)

K R, Sreenivas; Mohammad, Rafiuddin

2016-11-01

Predicting the fog-onset, its growth and dissipation helps in managing airports and other modes of transport. After sunset, occurrence of fog requires moist air, low wind and clear-sky conditions. Under these circumstances radiative heat transfer plays a vital role in the NBL. Locally, initiation of fog happens when the air temperature falls below the dew-point. Thus, to predict the onset of fog at a given location, one has to compute evolution of vertical temperature profile. Earlier,our group has shown that the presence of aerosols and vertical variation in their number density determines the radiative-cooling and hence development of vertical temperature profile. Aerosols, through radiation in the window-band, provides an efficient path for air layers to lose heat to the cold, upper atmosphere. This process creates cooler air layer between warmer ground and upper air layers and resulting temperature profile facilitate the initiation of fog. Our results clearly indicates that accounting for the presence of aerosols and their radiative-transfer is important in modeling micro-meteorological process of fog formation and its evolution. DST, Govt. INDIA.

The nominal cooling tower

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, R.

1995-12-31

The heat Rejection Industry defines a nominal cooling tower as circulating three gallons of water per minute (GPM) per ton of refrigeration from entering the tower at 95{degrees}F. Hot Water temperature (HWT) Leaving at 85{degrees}F Cold Water Temperature (CWT) at a Design Wet Bulb of 70{degrees}F (WBT). Manufacturers then provide a selection chart based on various wet bulb temperatures and HWTs. The wet bulb fluctuates and varies through out the world since it is the combination ambient temperature, relative humidity, and/or dew point. Different HWT and CWT requirements are usually charted as they change, so that the user can selectmore » the nominal cooling tower model recommended by the manufacturer. Ask any HVAC operator, refinery manager, power generating station operator what happens when the Wet Bulb reaches or exceeds the design WBT of the area. He probably will tell you, {open_quotes}My cooling tower works quite well, but in the summer time, I usually have trouble with it.{close_quotes} This occurs because he is operating a nominal cooling tower.« less

Cyanobacteria are confined to dewless habitats within a dew desert: Implications for past and future climate change for lithic microorganisms

NASA Astrophysics Data System (ADS)

Kidron, Giora J.; Starinsky, Abraham; Yaalon, Dan H.

2014-11-01

Although covering almost all rock outcrops around the world, little is known regarding the factors that govern the spatial distribution of lithic cyanobacteria and lichens. This is also the case in the Negev Desert, where cyanobacteria predominate on the rock outcrops of the south-facing slopes and lichens on the rock outcrops of the north-facing slopes. Hypothesizing that abiotic conditions determine their distribution, radiation, temperature, rain, dew and fog were monitored over a two-year period (2008-2010) at cyanobacteria- and lichen-dwelling habitats within a first-order drainage basin in the Negev Highlands. While non-significant differences characterized the rain amounts, substantial differences in substrate temperatures were recorded which resulted in turn in fundamental differences in the non-rainfall water regime. While dew condensed at the rock outcrops of the lichen habitat, no condensation took place at the cyanobacteria habitat. Contrary to the common belief, cyanobacteria were found to inhabit dewless habitats. As a result, cyanobacteria solely rely on rain precipitation for growth and can therefore serve as bioindicators for dewless habitats within the dewy Negev Desert. The findings may have important implications regarding Earth colonization, soil forming processes and geochemical processes following climate warming. They may explain lichen expansion and subsequent O2 increase during the mid Neoproterozoic providing indirect support for substantial photosynthetic activity and high weathering rates during this era.

Automated calibration of laser spectrometer measurements of δ18 O and δ2 H values in water vapour using a Dew Point Generator.

PubMed

Munksgaard, Niels C; Cheesman, Alexander W; Gray-Spence, Andrew; Cernusak, Lucas A; Bird, Michael I

2018-06-30

Continuous measurement of stable O and H isotope compositions in water vapour requires automated calibration for remote field deployments. We developed a new low-cost device for calibration of both water vapour mole fraction and isotope composition. We coupled a commercially available dew point generator (DPG) to a laser spectrometer and developed hardware for water and air handling along with software for automated operation and data processing. We characterised isotopic fractionation in the DPG, conducted a field test and assessed the influence of critical parameters on the performance of the device. An analysis time of 1 hour was sufficient to achieve memory-free analysis of two water vapour standards and the δ 18 O and δ 2 H values were found to be independent of water vapour concentration over a range of ≈20,000-33,000 ppm. The reproducibility of the standard vapours over a 10-day period was better than 0.14 ‰ and 0.75 ‰ for δ 18 O and δ 2 H values, respectively (1 σ, n = 11) prior to drift correction and calibration. The analytical accuracy was confirmed by the analysis of a third independent vapour standard. The DPG distillation process requires that isotope calibration takes account of DPG temperature, analysis time, injected water volume and air flow rate. The automated calibration system provides high accuracy and precision and is a robust, cost-effective option for long-term field measurements of water vapour isotopes. The necessary modifications to the DPG are minor and easily reversible. Copyright © 2018 John Wiley & Sons, Ltd.

Dew point effect of cooled hydrogel pads on human stratum corneum biosurface.

PubMed

Xhauflaire-Uhoda, Emmanuelle; Paquet, Philippe; Piérard, Gérald E

2008-01-01

Cooled hydrogel pads are used to prevent overheating effects of laser therapy. They do not induce cold injuries to the skin, but their more subtle physiological effects have not been thoroughly studied. To describe the changes in transepidermal water loss and electrometric properties of the skin surface following application of cooled hydrogel pads. Measurements were performed on normal forearm skin of 27 healthy volunteers and on freshly excised skin from abdominoplasty. LaserAid hydrogel pads cooled to 4 degrees C were placed for 15 min on the forearm skin. Measurements of transepidermal water loss (TEWL) and electrometric properties (Corneometer, Nova DPM 900) were performed before application and after removal of the cooled pads. A consistent increase in corneometer units, dermal phase meter (DPM) values and TEWL were recorded at removal of the cooled hydrogel pads. Both the in vivo and in vitro assessments brought similar information. The similar changes disclosed in vitro and in vivo suggest that a common physical process is operating in these conditions. The observed phenomenon is opposite to the predicted events given by the Arrhenius law probably because of the combination of cooling and occlusion by the pads. A dew point effect (air temperature at which relative humidity is maximal) is likely involved in the moisture content of the stratum corneum. Thus, the biological impact of using cooling hydrogel pads during laser therapy is different from the effect of a cryogenic spray cooling procedure. The better preservation of the water balance in the stratum corneum by the cooled hydrogel pads could have a beneficial esthetic effect on laser treated areas. (c) 2008 S. Karger AG, Basel.

Correlation of the protein structure and gelling properties in dried egg white products.

PubMed

Handa, A; Hayashi, K; Shidara, H; Kuroda, N

2001-08-01

The relationship between protein structure and aggregation, as well as heat-induced gelling properties, of seven dried egg white (DEW) products was investigated. Strong correlations were found between average molecular weight and hydrophobicity plus surface SH groups of DEW-soluble protein aggregate (SPA). This suggests that hydrophobic interactions and disulfide bond formation between protein molecules were involved in the aggregation. The average molecular weight of DEW products with alkaline pHs was relatively higher than those with neutral pHs and the same degree of protein unfolding, probably because of more disulfide bond formation between protein molecules. In addition, strong correlations were found between hydrophobicity, surface SH groups plus average molecular weight of DEW-SPA, and physical properties of the gels from DEW products. These data indicated that controlling the aggregation of DEW proteins in the dry state is crucial to controlling the gelling properties of DEW.

47 CFR 87.525 - Scope of service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Automatic Weather Stations (AWOS/ASOS) § 87.525 Scope of service. Automatic weather observation stations (AWOS) and automatic surface observation stations (ASOS) must provide up-to-date weather information including the time of the latest weather sequence, altimeter setting, wind speed and direction, dew point...

47 CFR 87.525 - Scope of service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Automatic Weather Stations (AWOS/ASOS) § 87.525 Scope of service. Automatic weather observation stations (AWOS) and automatic surface observation stations (ASOS) must provide up-to-date weather information including the time of the latest weather sequence, altimeter setting, wind speed and direction, dew point...

47 CFR 87.525 - Scope of service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Automatic Weather Stations (AWOS/ASOS) § 87.525 Scope of service. Automatic weather observation stations (AWOS) and automatic surface observation stations (ASOS) must provide up-to-date weather information including the time of the latest weather sequence, altimeter setting, wind speed and direction, dew point...

47 CFR 87.525 - Scope of service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Automatic Weather Stations (AWOS/ASOS) § 87.525 Scope of service. Automatic weather observation stations (AWOS) and automatic surface observation stations (ASOS) must provide up-to-date weather information including the time of the latest weather sequence, altimeter setting, wind speed and direction, dew point...

47 CFR 87.525 - Scope of service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Automatic Weather Stations (AWOS/ASOS) § 87.525 Scope of service. Automatic weather observation stations (AWOS) and automatic surface observation stations (ASOS) must provide up-to-date weather information including the time of the latest weather sequence, altimeter setting, wind speed and direction, dew point...

Water Potential in Excised Leaf Tissue

PubMed Central

Nelsen, Charles E.; Safir, Gene R.; Hanson, Andrew D.

1978-01-01

Leaf water potential (Ψleaf) determinations were made on excised leaf samples using a commercial dew point hygrometer (Wescor Inc., Logan, Utah) and a thermocouple psychrometer operated in the isopiestic mode. With soybean leaves (Glycine max L.), there was good agreement between instruments; equilibration times were 2 to 3 hours. With cereals (Triticum aestivum L. and Hordeum vulgare L.), agreement between instruments was poor for moderately wilted leaves when 7-mm-diameter punches were used in the hygrometer and 20-mm slices were used in the psychrometer, because the Ψleaf values from the dew point hygrometer were too high. Agreement was improved by replacing the 7-mm punch samples in the hygrometer by 13-mm slices, which had a lower cut edge to volume ratio. Equilibration times for cereals were normally 6 to 8 hours. Spuriously high Ψleaf values obtained with 7-mm leaf punches may be associated with the ion release and reabsorption that occur upon tissue excision; such errors evidently depend both on the species and on tissue water status. PMID:16660227

Using Ice Nucleating Particles to Enable Desublimation on Chilled Substrates

NASA Astrophysics Data System (ADS)

O'Brien, Julia; Failor, Kevin; Bisbano, Caitlin; Mulroe, Megan; Nath, Saurabh; Vinatzer, Boris; Boreyko, Jonathan

2017-11-01

On a subfreezing surface, nucleating embryos usually form as supercooled condensate that later freeze into ice, as opposed to desublimation. Ice nucleating particles (INPs) have been widely used to freeze existing water; however, nobody has studied how they might affect the initial mode of nucleation. Here, we show that INPs deposited on a substrate can switch the mode of embryo nucleation to desublimation, rather than supercooled condensation. Deposition was achieved by evaporating a water droplet containing INPs on a hydrophobic silicon wafer. A Peltier stage was used to cool the wafer down inside of a controlled humidity chamber, such that the desired set point temperature correlated with the dew point and onset of nucleation. Beneath a critical surface temperature, microscopy indicated that desublimation occurred on the circular patch of deposited INPs, compared to supercooled condensation outside the circle. The hydrophobic surface was then patterned with hydrophilic stripe arrays, which facilitated the deposition of stripes of INPs via the same evaporation method. The resulting array of desublimating ice stripes created dry zones free of condensation or frost in the intermediate areas, as the hygroscopic ice stripes served as overlapping humidity sinks.

Plant growth modeling at the JSC variable pressure growth chamber - An application of experimental design

NASA Technical Reports Server (NTRS)

Miller, Adam M.; Edeen, Marybeth; Sirko, Robert J.

1992-01-01

This paper describes the approach and results of an effort to characterize plant growth under various environmental conditions at the Johnson Space Center variable pressure growth chamber. Using a field of applied mathematics and statistics known as design of experiments (DOE), we developed a test plan for varying environmental parameters during a lettuce growth experiment. The test plan was developed using a Box-Behnken approach to DOE. As a result of the experimental runs, we have developed empirical models of both the transpiration process and carbon dioxide assimilation for Waldman's Green lettuce over specified ranges of environmental parameters including carbon dioxide concentration, light intensity, dew-point temperature, and air velocity. This model also predicts transpiration and carbon dioxide assimilation for different ages of the plant canopy.

40 CFR 86.346-79 - Alternative NOX measurement technique.

Code of Federal Regulations, 2012 CFR

2012-07-01

... following “alternative instrumentation” for both Diesel and gasoline-fueled engines. The “alternative instrumentation” shall consist of: (1) A heated sample line maintained above the dew point: (2) An NO2 to NO... the “alternative instrumentation”, where applicable, with the following exceptions: (1) Analyzer...

40 CFR 86.346-79 - Alternative NOX measurement technique.

Code of Federal Regulations, 2011 CFR

2011-07-01

... following “alternative instrumentation” for both Diesel and gasoline-fueled engines. The “alternative instrumentation” shall consist of: (1) A heated sample line maintained above the dew point: (2) An NO2 to NO... the “alternative instrumentation”, where applicable, with the following exceptions: (1) Analyzer...

40 CFR 86.346-79 - Alternative NOX measurement technique.

Code of Federal Regulations, 2010 CFR

2010-07-01

... following “alternative instrumentation” for both Diesel and gasoline-fueled engines. The “alternative instrumentation” shall consist of: (1) A heated sample line maintained above the dew point: (2) An NO2 to NO... the “alternative instrumentation”, where applicable, with the following exceptions: (1) Analyzer...

40 CFR 86.346-79 - Alternative NOX measurement technique.

Code of Federal Regulations, 2013 CFR

2013-07-01

... following “alternative instrumentation” for both Diesel and gasoline-fueled engines. The “alternative instrumentation” shall consist of: (1) A heated sample line maintained above the dew point: (2) An NO2 to NO... the “alternative instrumentation”, where applicable, with the following exceptions: (1) Analyzer...

Aerosol Attenuation in the 2-4 Micrometer Region

DTIC Science & Technology

1975-03-01

Company Model 911ir dew point hydrometer. The lithium chloride sensors will be placed on the roof where the aerosol is sampled and at the entrance...Extinction Measurement il External View of 400 Meter White Cell 13 Primary Aerosol and Gas Handlinfe Systems 14 Calibration for Extinction...Massacusetts. Aerosol-laden air will be drawn into the experimental apparatus from a point 10 ft above the roof of the building. A continuoush

The importance of dew in watershed-management research

Treesearch

James W. Hornbeck

1964-01-01

Many studies, using various methods, have been made of dew deposition to determine its importance as a source of moisture. For example, Duvdevani (1947) used an optical method in which dew collected on a wooden block was compared with a set of standardized photographs of dew. Potvin (1949) exposed diamond-shaped glass plates at 45º to ground level, so that...

AALC Fan Model Test Program

DTIC Science & Technology

1979-05-08

Prediction. Scaling. Fan Design. 29AOSY14ACY (Cettm.. a P#`04 rv1s. *It UO004N 01- dew 16001 bYstI 610 01c Nh A 12-inch-diameter centrifugal fan impeller...Performance, 3500 RPM84............ 53 Inlet Bellmouth Velocity Survey , Oper Point A, Config 3. 54 Inlet Bellmouth Velocity Survey, Oper Point B...Config 3. 8& 55 Inlet Bellmouth Velocity Survey, Oper Point C, Config 3. ss So Volute Exit Plane Press. Measurement Locations, Config 3 89 57 Volute Exit

MesoNAM Verification Phase II

NASA Technical Reports Server (NTRS)

Watson, Leela R.

2011-01-01

The 45th Weather Squadron Launch Weather Officers use the 12-km resolution North American Mesoscale model (MesoNAM) forecasts to support launch weather operations. In Phase I, the performance of the model at KSC/CCAFS was measured objectively by conducting a detailed statistical analysis of model output compared to observed values. The objective analysis compared the MesoNAM forecast winds, temperature, and dew point to the observed values from the sensors in the KSC/CCAFS wind tower network. In Phase II, the AMU modified the current tool by adding an additional 15 months of model output to the database and recalculating the verification statistics. The bias, standard deviation of bias, Root Mean Square Error, and Hypothesis test for bias were calculated to verify the performance of the model. The results indicated that the accuracy decreased as the forecast progressed, there was a diurnal signal in temperature with a cool bias during the late night and a warm bias during the afternoon, and there was a diurnal signal in dewpoint temperature with a low bias during the afternoon and a high bias during the late night.

Sea Fog Forecasting with Lagrangian Models

NASA Astrophysics Data System (ADS)

Lewis, J. M.

2014-12-01

In 1913, G. I. Taylor introduced us to a Lagrangian view of sea fog formation. He conducted his study off the coast of Newfoundland in the aftermath of the Titanic disaster. We briefly review Taylor's classic work and then apply these same principles to a case of sea fog formation and dissipation off the coast of California. The resources used in this study consist of: 1) land-based surface and upper-air observations, 2) NDBC (National Data Buoy Center) observations from moored buoys equipped to measure dew point temperature as well as the standard surface observations at sea (wind, sea surface temperature, pressure, and air temperature), 3) satellite observations of cloud, and 4) a one-dimensional (vertically directed) boundary layer model that tracks with the surface air motion and makes use of sophisticated turbulence-radiation parameterizations. Results of the investigation indicate that delicate interplay and interaction between the radiation and turbulence processes makes accurate forecasts of sea fog onset unlikely in the near future. This pessimistic attitude stems from inadequacy of the existing network of observations and uncertainties in modeling dynamical processes within the boundary layer.

The effect of environmental humidity and temperature on skin barrier function and dermatitis.

PubMed

Engebretsen, K A; Johansen, J D; Kezic, S; Linneberg, A; Thyssen, J P

2016-02-01

Physicians are aware that climatic conditions negatively affect the skin. In particular, people living in equator far countries such as the Northern parts of Europe and North America are exposed to harsh weather during the winter and may experience dry and itchy skin, or deterioration of already existing dermatoses. We searched the literature for studies that evaluated the mechanisms behind this phenomenon. Commonly used meteorological terms such as absolute humidity, relative humidity and dew point are explained. Furthermore, we review the negative effect of low humidity, low temperatures and different seasons on the skin barrier and on the risk of dermatitis. We conclude that low humidity and low temperatures lead to a general decrease in skin barrier function and increased susceptible towards mechanical stress. Since pro-inflammatory cytokines and cortisol are released by keratinocytes, and the number of dermal mast cells increases, the skin also becomes more reactive towards skin irritants and allergens. Collectively, published data show that cold and dry weather increase the prevalence and risk of flares in patients with atopic dermatitis. © 2015 European Academy of Dermatology and Venereology.

The use of DMA to characterize the aging of asphalt binders : tech summary.

DOT National Transportation Integrated Search

2010-06-01

Most of U.S. southeastern states experience both hot and wet summer weather. Extremely high relative humidity and a : low dew point maintain a continuous fi lm of water on Gulf Coast roads during the night and early morning hours. Should : the labora...

77 FR 15813 - Preoperational Testing of Instrument and Control Air Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-16

... seismic requirement, ICAS air-dryer testing to meet dew point design requirements, ICAS accumulator check... ensure consideration only for comments received on or before this date. Although a time limit is given... improvements in all published guides are encouraged at any time. ADDRESSES: You may access information and...

Simple Techniques for Microclimate Measurement.

ERIC Educational Resources Information Center

Unwin, D. M.

1978-01-01

Describes simple ways of measuring the very local climate near the ground, and explains what these measurements mean. Equipment included a solar radiometer, a dew point instrument, and a thermocouple psychrometer. Examples are given of field measurements taken with some of the equipment and the results and their interpretation are discussed.…

Liquid oil production from shale gas condensate reservoirs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, James J.

A process of producing liquid oil from shale gas condensate reservoirs and, more particularly, to increase liquid oil production by huff-n-puff in shale gas condensate reservoirs. The process includes performing a huff-n-puff gas injection mode and flowing the bottom-hole pressure lower than the dew point pressure.

A conceptual weather-type classification procedure for the Philadelphia, Pennsylvania, area

USGS Publications Warehouse

McCabe, Gregory J.

1990-01-01

A simple method of weather-type classification, based on a conceptual model of pressure systems that pass through the Philadelphia, Pennsylvania, area, has been developed. The only inputs required for the procedure are daily mean wind direction and cloud cover, which are used to index the relative position of pressure systems and fronts to Philadelphia.Daily mean wind-direction and cloud-cover data recorded at Philadelphia, Pennsylvania, from January 1954 through August 1988 were used to categorize daily weather conditions. The conceptual weather types reflect changes in daily air and dew-point temperatures, and changes in monthly mean temperature and monthly and annual precipitation. The weather-type classification produced by using the conceptual model was similar to a classification produced by using a multivariate statistical classification procedure. Even though the conceptual weather types are derived from a small amount of data, they appear to account for the variability of daily weather patterns sufficiently to describe distinct weather conditions for use in environmental analyses of weather-sensitive processes.

Space vehicle with artificial gravity and earth-like environment

NASA Technical Reports Server (NTRS)

Gray, V. H. (Inventor)

1973-01-01

A space vehicle adapted to provide an artificial gravity and earthlike atmospheric environment for occupants is disclosed. The vehicle comprises a cylindrically shaped, hollow pressure-tight body, one end of which is tapered from the largest diameter of the body, the other end is flat and transparent to sunlight. The vehicle is provided with thrust means which rotates the body about its longitudinal axis, generating an artificial gravity effect upon the interior walls of the body due to centrifugal forces. The walls of the tapered end of the body are maintained at a temperature below the dew point of water vapor in the body and lower than the temperature near the transparent end of the body. The controlled environment and sunlight permits an earth like environment to be maintained wherein the CO2/O2 is balanced, and food for the travelers is supplied through a natural system of plant life grown on spacecraft walls where soil is located.

Cannon AFB, Clovis, New Mexico. Revised Uniform Summary of Surface Weather Observations (RUSSWO), Parts A-F

DTIC Science & Technology

1975-06-16

dry -bulb temperature, means and standard d~viatinne nf eirg-hiiih- wM~e-.h,lh (y DD 1473 ~ UNCLASSIFIED SECURIS- CLASSIFICATION OF THIS PAGE(Ifnon...Val. Entoted) 19. Percentqge frequency of distribution tables Dry -bulb temperature versus wet-bulb temperature Cumulative percentage frequency of...ATMOSPHERIC PHENOMENA EXTREME MAX & MIN TEMP PART B PRECIPITATION PSYCHROMETRIC- DRY VS WET BULB SNOWFALL MEAN & STD DEV - ( DRY BULB, WET BULB, & DEW

The Achene Mucilage Hydrated in Desert Dew Assists Seed Cells in Maintaining DNA Integrity: Adaptive Strategy of Desert Plant Artemisia sphaerocephala

PubMed Central

Yang, Xuejun; Zhang, Wenhao; Dong, Ming; Boubriak, Ivan; Huang, Zhenying

2011-01-01

Despite proposed ecological importance of mucilage in seed dispersal, germination and seedling establishment, little is known about the role of mucilage in seed pre-germination processes. Here we investigated the role of mucilage in assisting achene cells to repair DNA damage during dew deposition in the desert. Artemisia sphaerocephala achenes were first treated γ-irradiation to induce DNA damage, and then they were repaired in situ in the desert dew. Dew deposition duration can be as long as 421 min in early mornings. Intact achenes absorbed more water than demucilaged achenes during dew deposition and also carried water for longer time following sunrise. After 4-d dew treatment, DNA damage of irradiated intact and demucilaged achenes was reduced to 24.38% and 46.84%, respectively. The irradiated intact achenes exhibited much higher DNA repair ratio than irradiated demucilaged achenes. Irradiated intact achenes showed an improved germination and decreased nonviable achenes after dew treatment, and significant differences in viability between the two types of achenes were detected after 1020 min of dew treatment. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding DNA repair of achene cells in genomic-stressful habitats. PMID:21912689

Satellite-derived vertical profiles of temperature and dew point for mesoscale weather forecast

NASA Astrophysics Data System (ADS)

Masselink, Thomas; Schluessel, P.

1995-12-01

Weather forecast-models need spatially high resolutioned vertical profiles of temperature and dewpoint for their initialisation. These profiles can be supplied by a combination of data from the Tiros-N Operational Vertical Sounder (TOVS) and the imaging Advanced Very High Resolution Radiometer (AVHRR) on board the NOAA polar orbiting sate!- lites. In cloudy cases the profiles derived from TOVS data only are of insufficient accuracy. The stanthrd deviations from radiosonde ascents or numerical weather analyses likely exceed 2 K in temperature and 5Kin dewpoint profiles. It will be shown that additional cloud information as retrieved from AVHIRR allows a significant improvement in theaccuracy of vertical profiles. The International TOVS Processing Package (ITPP) is coupled to an algorithm package called AVHRR Processing scheme Over cLouds, Land and Ocean (APOLLO) where parameters like cloud fraction and cloud-top temperature are determined with higher accuracy than obtained from TOVS retrieval alone. Furthermore, a split-window technique is applied to the cloud-free AVHRR imagery in order to derive more accurate surface temperatures than can be obtained from the pure TOVS retrieval. First results of the impact of AVHRR cloud detection on the quality of the profiles are presented. The temperature and humidity profiles of different retrieval approaches are validated against analyses of the European Centre for Medium-Range Weatherforecasts.

Artificial intelligence based approach to forecast PM2.5 during haze episodes: A case study of Delhi, India

NASA Astrophysics Data System (ADS)

Mishra, Dhirendra; Goyal, P.; Upadhyay, Abhishek

2015-02-01

Delhi has been listed as the worst performer across the world with respect to the presence of alarmingly high level of haze episodes, exposing the residents here to a host of diseases including respiratory disease, chronic obstructive pulmonary disorder and lung cancer. This study aimed to analyze the haze episodes in a year and to develop the forecasting methodologies for it. The air pollutants, e.g., CO, O3, NO2, SO2, PM2.5 as well as meteorological parameters (pressure, temperature, wind speed, wind direction index, relative humidity, visibility, dew point temperature, etc.) have been used in the present study to analyze the haze episodes in Delhi urban area. The nature of these episodes, their possible causes, and their major features are discussed in terms of fine particulate matter (PM2.5) and relative humidity. The correlation matrix shows that temperature, pressure, wind speed, O3, and dew point temperature are the dominating variables for PM2.5 concentrations in Delhi. The hour-by-hour analysis of past data pattern at different monitoring stations suggest that the haze hours were occurred approximately 48% of the total observed hours in the year, 2012 over Delhi urban area. The haze hour forecasting models in terms of PM2.5 concentrations (more than 50 μg/m3) and relative humidity (less than 90%) have been developed through artificial intelligence based Neuro-Fuzzy (NF) techniques and compared with the other modeling techniques e.g., multiple linear regression (MLR), and artificial neural network (ANN). The haze hour's data for nine months, i.e. from January to September have been chosen for training and remaining three months, i.e., October to December in the year 2012 are chosen for validation of the developed models. The forecasted results are compared with the observed values with different statistical measures, e.g., correlation coefficients (R), normalized mean square error (NMSE), fractional bias (FB) and index of agreement (IOA). The performed analysis has indicated that R has values 0.25 for MLR, 0.53 for ANN, and NF: 0.72, between the observed and predicted PM2.5 concentrations during haze hours invalidation period. The results show that the artificial intelligence implementations have a more reasonable agreement with the observed values. Finally, it can be concluded that the most convincing advantage of artificial intelligence based NF model is capable for better forecasting of haze episodes in Delhi urban area than ANN and MLR models.

The New Lunar Meteorite DEW 12007

NASA Astrophysics Data System (ADS)

Collareta, A.; D'Orazio, M.; Gemelli, M.; Pack, A.; Folco, L.

2014-09-01

The new lunar meteorite DEW 12007 was found in Antarctica in January 2013 by PNRA. DEW 12007 has been classified as a regolithic breccia of mingled composition. In our abstract we present its first-order geochemical and petrographic features.

The impact of the disease early warning system in responding to natural disasters and conflict crises in Pakistan.

PubMed

Rahim, M; Kazi, B M; Bile, K M; Munir, M; Khan, A R

2010-01-01

The disease early warning system (DEWS) was introduced in the immediate aftermath of the 2005 earthquake in Pakistan, with the objective to undertake prompt investigation and mitigation of disease outbreaks. The DEWS network was replicated successfully during subsequent flood and earthquake disasters as well as during the 2008-09 internally displaced persons' crisis. DEWS-generated alerts, prompt investigations and timely responses had an effective contribution to the control of epidemics. Through DEWS, 1360 reported alerts during 2005-09 averted the risk of disease outbreaks through pre-emptive necessary measures, while the 187 confirmed outbreaks were effectively controlled. In the aftermath of the disasters, DEWS technology also facilitated the development of a disease-surveillance system that became an integral part of the district health system. This study aims to report the DEWS success and substantiate its lead role as a priority emergency health response intervention.

A numerical model for boiling heat transfer coefficient of zeotropic mixtures

NASA Astrophysics Data System (ADS)

Barraza Vicencio, Rodrigo; Caviedes Aedo, Eduardo

2017-12-01

Zeotropic mixtures never have the same liquid and vapor composition in the liquid-vapor equilibrium. Also, the bubble and the dew point are separated; this gap is called glide temperature (Tglide). Those characteristics have made these mixtures suitable for cryogenics Joule-Thomson (JT) refrigeration cycles. Zeotropic mixtures as working fluid in JT cycles improve their performance in an order of magnitude. Optimization of JT cycles have earned substantial importance for cryogenics applications (e.g, gas liquefaction, cryosurgery probes, cooling of infrared sensors, cryopreservation, and biomedical samples). Heat exchangers design on those cycles is a critical point; consequently, heat transfer coefficient and pressure drop of two-phase zeotropic mixtures are relevant. In this work, it will be applied a methodology in order to calculate the local convective heat transfer coefficients based on the law of the wall approach for turbulent flows. The flow and heat transfer characteristics of zeotropic mixtures in a heated horizontal tube are investigated numerically. The temperature profile and heat transfer coefficient for zeotropic mixtures of different bulk compositions are analysed. The numerical model has been developed and locally applied in a fully developed, constant temperature wall, and two-phase annular flow in a duct. Numerical results have been obtained using this model taking into account continuity, momentum, and energy equations. Local heat transfer coefficient results are compared with available experimental data published by Barraza et al. (2016), and they have shown good agreement.

Dew Point Evaporative Comfort Cooling

DTIC Science & Technology

2013-07-01

efficiency ratio kBtu kilo British thermal unit kW kilowatt kWh kilowatt-hour M-Cycle Maisotsenko Cycle MCDB mean coincident dry bulb mi2 square...the foothills of the Rocky Mountains. The base covers more than 8.7 square miles ( mi2 ) and includes more than 11 million ft2 of building area

Aircraft measurements and analysis of severe storms: 1975 field experiment

NASA Technical Reports Server (NTRS)

Sinclair, P. C.

1976-01-01

Three aircraft and instrumentation systems were acquired in support of the severe storm surveillance program. The data results indicate that the original concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, dew point, etc., near and within specifically designated severe storms is entirely feasible and has been demonstrated for the first time by this program. This program is unique in that it is designed to be highly mobile in order to move to and/or with the developing storm systems to obtain the necessary measurements. Previous programs have all been fixed to a particular location and therefore have had to wait for the storms to come within their network. The present research is designed around a highly mobile aircraft measurements group in order to maximize the storm cases during the field measurements program.

Novel ideas for maximising dew collection to aid plant establishment to combat desertification and restore degraded dry and arid lands

NASA Astrophysics Data System (ADS)

Kotzen, Benz

2014-05-01

This paper focuses on the potential of dew to provide water to plants and potentially to people as well in remote and difficult to reach areas where rainfall and underground water cannot be harvested. The combat of desertification and the restoration of degraded and desertified dry and arid lands has never been more urgent. A key practical component of this strategy is the restoration of habitat with planting. But for habitat and planting to survive there needs to be an adequate supply of water. In most cases providing water to the plant's roots is vital. In some areas where habitats have been destroyed, sufficient water is immediately available, for example through seasonal rainfall, or it can be harvested to concentrate adequate supplies of water to the roots. However, in arid and hyper arid areas, as well as in some dryland areas, a consistent and adequate supply of water cannot be provided by any conventional proven method. Thus, as the need to combat desertification and to restore desertified dry and arid land increases, so the need to find novel methods of establishing and maintaining planting and thus habitat increases. In more traditional land management scenarios this can be achieved through manipulating landform on a micro and macro scale, for example, by creating catchments, thereby collecting precipitation and directing it to the plants. Where this cannot be done, other means of water supply are usually required. Bainbridge (2007) and others have shown that supplying water to plants is possible through a number of traditional methods, for example, using clay pots. But most of these techniques require an introduced source of water, for example, obtained through water harvesting methods or by delivering water to site in tanks and by water bowser. This can work but requires continuous manpower. It is expensive and can be physically prohibitive in areas where access is difficult and/or remote. The concept of using dew to supply water in drylands is not new and numerous studies have been undertaken to investigate past so-called dew collectors and to research the possibilities of using new ones. Most of the historical dew collectors have been disputed as dew collection devices. (Beysens et al 2006, Beysens et al in Kogan and Trahtman 2006, Graf et al 2008.) However, contemporary dew collection has proven possible in those areas that have dew fall. It is generally agreed by researchers, such as Sharan and Beysens in 2007 and Jacobs et al in 2008 after Monteith (1957) that the theoretical maximum dew yield is in the order of 0.8 l/m2/day. Although the exact maximum has never been defined the amounts can yet be significant. However, In most cases the investigations of dew supply in areas where dew is known to precipitate has been undertaken with inclined roof like planar surfaces. However, erecting these planes in remote areas and within difficult terrain makes this kind of collector impractical. Additionally such planar surfaces demand space on the ground which then diminishes the areas of restoration and large collectors require additional plumbing to distribute water to the plants themselves. Thus in order to better supply dew to plants other forms are required. This paper discusses the various ideas and concepts that have been developed for dew collection that have emerged on the market and the novel ideas that have been initiated by the author. The research undertaken investigates biomimetic forms which emulate plant forms such as various cacti and succulents investigating their ability to increase surface area as well as releasing heat like a radiator. Additionally other spiky, needle like forms are investigated as well as animal forms, such as the surface of the Stenocara gracilipes Namibian beetle which collects fog. The research initiated a new strategy for dew collection dividing dew collectors into two types: 1) Passive dew collectors, where nightly collection and delivery is achieved without people, and 2) Semi-passive dew collectors, which require people to collect the dew after it has formed on the dew collector. Bibliography Bainbridge D.A., 2007, 'A Guide for Desert and Dryland Restoration', Island Press. Beysens, D., Milimouk I., Nikolayev, V. S., Berkowicz, S., Muselli, M., Heusinkveld, B., and Jacobs, A. F. G., 2006, 'Comment on "The moisture from the air as water resource in arid region: Hopes, doubt and facts'' by Kogan and Trahtman', Journal of Arid Environments 67 (2006) 343-352. Beysens, D., Muselli, M., Ohayone, C., Berkowicz, S. M., Soyeux, E., Mileta, M., Ortega, P., 2006, 'Application of passive radiative cooling for dew condensation', Energy 31 (2006) 2303-2315. Jacobs, A. F. G., Heusinkveld, B. G. and Berkowicz, S. M., 2008, 'Passive dew collection in a grassland area, The Netherlands', Atmospheric Research 87 (2008) 377-385. Monteith, J.L., 1957. 'Dew', Quarterly Journal of Royal Meteorological Society 83, 322-341. Sharan, G., Beysens, D., and Milimouk-Melnytchouk, I., 2007, 'A study of dew water yields on Galvanized iron roofs in Kothara (North-West India)', Journal of Arid Environments 69 (2007) 259-269.

Characterization of canopy dew formation in tropical forests using active microwave remote sensing

NASA Astrophysics Data System (ADS)

Gerlein-Safdi, C.; Frolking, S. E.; Caylor, K. K.

2016-12-01

Dew deposition in a closed canopy is thought to be greatest on top of the canopy, since a clear view of the sky increases condensation. In tropical forests, these same leaves are also subject to direct sunlight and high transpiration rates. Dew deposition can offset some of the water stress through foliar uptake of the dew droplets, or transpiration suppression from the energy dissipation associated with dew evaporation. However, the long-term trends of dew formation and their global patterns have received little attention, despite the wide acknowledgement that non-meteoric water can be a key source of water for many species, especially in tropical ecosystems. As such, accumulated and future effects of climate change on non-meteoric water occurrence remain an under-appreciated and unquantified factor in determining the risks that tropical ecosystems face. In this presentation, we simulate the effects of a wet canopy on satellite-based microwave backscatter by modifying the Michigan Microwave Canopy Scattering Model to account for the presence of dew droplets. We apply this model to estimate the canopy water storage derived from the SeaWinds Scatterometer aboard the QuikSCAT satellite by comparing the 6AM and 6PM microwave retrievals. We examine dew frequency and amount in tropical forests in South America, Africa and South-East Asia. Using the 10 years of available data, we investigate trends in dew formation in these three areas and speculate on the potential impact of the observed changes on dew-dependent tropical ecosystems.Finally, we compare our results to locally measured and modeled leaf wetness data. With multiple recently-launched instruments providing new data, strong correlations between satellite-based canopy water storage and in-situ data indicate the possibility of novel applications of microwave backscatter datasets in closed canopies ecosystems, such as the estimation of canopy interception or leaf-water content.

Determination of end point of primary drying in freeze-drying process control.

PubMed

Patel, Sajal M; Doen, Takayuki; Pikal, Michael J

2010-03-01

Freeze-drying is a relatively expensive process requiring long processing time, and hence one of the key objectives during freeze-drying process development is to minimize the primary drying time, which is the longest of the three steps in freeze-drying. However, increasing the shelf temperature into secondary drying before all of the ice is removed from the product will likely cause collapse or eutectic melt. Thus, from product quality as well as process economics standpoint, it is very critical to detect the end of primary drying. Experiments were conducted with 5% mannitol and 5% sucrose as model systems. The apparent end point of primary drying was determined by comparative pressure measurement (i.e., Pirani vs. MKS Baratron), dew point, Lyotrack (gas plasma spectroscopy), water concentration from tunable diode laser absorption spectroscopy, condenser pressure, pressure rise test (manometric temperature measurement or variations of this method), and product thermocouples. Vials were pulled out from the drying chamber using a sample thief during late primary and early secondary drying to determine percent residual moisture either gravimetrically or by Karl Fischer, and the cake structure was determined visually for melt-back, collapse, and retention of cake structure at the apparent end point of primary drying (i.e., onset, midpoint, and offset). By far, the Pirani is the best choice of the methods tested for evaluation of the end point of primary drying. Also, it is a batch technique, which is cheap, steam sterilizable, and easy to install without requiring any modification to the existing dryer.

Observation and modelling of urban dew

NASA Astrophysics Data System (ADS)

Richards, Katrina

Despite its relevance to many aspects of urban climate and to several practical questions, urban dew has largely been ignored. Here, simple observations an out-of-doors scale model, and numerical simulation are used to investigate patterns of dewfall and surface moisture (dew + guttation) in urban environments. Observations and modelling were undertaken in Vancouver, B.C., primarily during the summers of 1993 and 1996. Surveys at several scales (0.02-25 km) show that the main controls on dew are weather, location and site configuration (geometry and surface materials). Weather effects are discussed using an empirical factor, FW . Maximum dew accumulation (up to ~ 0.2 mm per night) is seen on nights with moist air and high FW , i.e., cloudless conditions with light winds. Favoured sites are those with high Ysky and surfaces which cool rapidly after sunset, e.g., grass and well insulated roofs. A 1/8-scale model is designed, constructed, and run at an out-of-doors site to study dew patterns in an urban residential landscape which consists of house lots, a street and an open grassed park. The Internal Thermal Mass (ITM) approach is used to scale the thermal inertia of buildings. The model is validated using data from full-scale sites in Vancouver. Patterns in the model agree with those seen at the full-scale, i.e., dew distribution is governed by weather, site geometry and substrate conditions. Correlation is shown between Ysky and surface moisture accumulation. The feasibility of using a numerical model to simulate urban dew is investigated using a modified version of a rural dew model. Results for simple isolated surfaces-a deciduous tree leaf and an asphalt shingle roof-show promise, especially for built surfaces.

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flaherty, Julia E.; Glissmeyer, John A.

2015-03-18

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilutionmore » system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.« less

Dew Worms in the White Nights

USDA-ARS?s Scientific Manuscript database

Lumbricus terrestris L. (the dew worm) forages, mates and migrates on the soil surface during the night. Its distribution covers a broad latitudinal gradient and variation in day length conditions. Since soil-surface activity is crucial for the survival and reproduction of dew worms, it is conceivab...

Site Specific Probable Maximum Precipitation Estimates and Professional Judgement

NASA Astrophysics Data System (ADS)

Hayes, B. D.; Kao, S. C.; Kanney, J. F.; Quinlan, K. R.; DeNeale, S. T.

2015-12-01

State and federal regulatory authorities currently rely upon the US National Weather Service Hydrometeorological Reports (HMRs) to determine probable maximum precipitation (PMP) estimates (i.e., rainfall depths and durations) for estimating flooding hazards for relatively broad regions in the US. PMP estimates for the contributing watersheds upstream of vulnerable facilities are used to estimate riverine flooding hazards while site-specific estimates for small water sheds are appropriate for individual facilities such as nuclear power plants. The HMRs are often criticized due to their limitations on basin size, questionable applicability in regions affected by orographic effects, their lack of consist methods, and generally by their age. HMR-51 for generalized PMP estimates for the United States east of the 105th meridian, was published in 1978 and is sometimes perceived as overly conservative. The US Nuclear Regulatory Commission (NRC), is currently reviewing several flood hazard evaluation reports that rely on site specific PMP estimates that have been commercially developed. As such, NRC has recently investigated key areas of expert judgement via a generic audit and one in-depth site specific review as they relate to identifying and quantifying actual and potential storm moisture sources, determining storm transposition limits, and adjusting available moisture during storm transposition. Though much of the approach reviewed was considered a logical extension of HMRs, two key points of expert judgement stood out for further in-depth review. The first relates primarily to small storms and the use of a heuristic for storm representative dew point adjustment developed for the Electric Power Research Institute by North American Weather Consultants in 1993 in order to harmonize historic storms for which only 12 hour dew point data was available with more recent storms in a single database. The second issue relates to the use of climatological averages for spatially interpolating 100-year dew point values rather than a more gauge-based approach. Site specific reviews demonstrated that both issues had potential for lowering the PMP estimate significantly by affecting the in-place and transposed moisture maximization value and, in turn, the final controlling storm for a given basin size and PMP estimate.

Evaluation of a 2.5 kWel automotive low temperature PEM fuel cell stack with extended operating temperature range up to 120 °C

NASA Astrophysics Data System (ADS)

Ruiu, Tiziana; Dreizler, Andreas M.; Mitzel, Jens; Gülzow, Erich

2016-01-01

Nowadays, the operating temperature of polymer electrolyte membrane fuel cell stacks is typically limited to 80 °C due to water management issues of membrane materials. In the present work, short-term operation at elevated temperatures up to 120 °C and long-term steady-state operation under automotive relevant conditions at 80 °C are examined using a 30-cell stack developed at DLR. The high temperature behavior is investigated by using temperature cycles between 90 and 120 °C without adjustment of the gases dew points, to simulate a short-period temperature increase, possibly caused by an extended power demand and/or limited heat removal. This galvanostatic test demonstrates a fully reversible performance decrease of 21 ± 1% during each thermal cycle. The irreversible degradation rate is about a factor of 6 higher compared to the one determined by the long-term test. The 1200-h test at 80 °C demonstrates linear stack voltage decay with acceptable degradation rate, apart from a malfunction of the air compressor, which results in increased catalyst degradation effects on individual cells. This interpretation is based on an end-of-life characterization, aimed to investigate catalyst, electrode and membrane degradation, by determining hydrogen crossover rates, high frequency resistances, electrochemically active surface areas and catalyst particle sizes.

Variability of Tear Osmolarity Measurements With a Point-of-Care System in Healthy Subjects-Systematic Review.

PubMed

Baenninger, Philipp B; Voegeli, Susanne; Bachmann, Lucas M; Faes, Livia; Iselin, Katja; Kaufmann, Claude; Thiel, Michael A

2018-04-04

To assess the variability of osmolarity measured by the point-of-care TearLab system in healthy eyes. A systematic review was performed by searching MEDLINE, Scopus, and the Web of Science Databases until November 2016 and checking reference lists of included articles and reviews. The requirements for inclusion were the availability of TearLab results in healthy subjects and a minimum study sample of 20 eyes. Two reviewers assessed articles against the inclusion criteria, extracted relevant data, and examined the methodological quality. We computed the weighted mean osmolarity using the study size as the weighting factor and calculated the rate of subjects with osmolarity values >308 mOsm/L, the Dry Eye Workshop Report 2017 (DEWS) cut-off value for dry eye disease (DED). We repeated the analysis after excluding reports with a possible conflict of interest or missing description of subject selection. Searches retrieved 105 nonduplicate articles, and we included 33 studies investigating 1362 eyes of healthy participants who were asymptomatic and showed no clinical signs of DED. Sixty-three percent were female, and mean age was 37.3 years (range: 21.5-69.0 yr). Weighted mean osmolarity was 298 mOsm/L (95% confidence interval, 282-321 mOsm/L). The result of the subgroup analysis was similar. Overall, 386 of 1362 eyes (28.3%) fulfilled the DEWS's definition of DED (>308 mOsm/L). There is a high variability of osmolarity measurements with the TearLab system. A substantial number of healthy subjects fulfill the DEWS's definition of DED. We propose interpreting the TearLab osmolarity results cautiously and in the context of other established methods.

Meteorological Techniques (Revision 26 Apr 2006)

DTIC Science & Technology

2003-06-13

OVV Graph ------------------------------------------------------------------------ 2-11 Figure 2-26 Dissipation of Stratus Using Mixing Ratio and...2-51 Figure 2-70 Bright Band Identification Using the WSR-88D. ------------------------------------------ 2-52 Figure 2-71 Example of Visible...R2, and R3 relative humidity values and cloud amounts ------------------------- 2-7 Table 2-4 Base of convective clouds using surface dew-point

Wet-Atmosphere Generator

NASA Technical Reports Server (NTRS)

Hamner, Richard M.; Mcguire, Janice K.

1988-01-01

Water content in gas controlled. Portable flow-control system generates nitrogen/water atmosphere having range of dew points and pressures. One use of system provides wet nitrogen for canister of wide-field camera requiring this special atmosphere. Also used to inject trace gases other than water vapor for leak testing of large vessels. Potential applications in photography, hospitals, and calibration laboratories.

Sweating Like a Pig: Physics or Irony?

ERIC Educational Resources Information Center

Bohren, Craig F.

2016-01-01

In his interesting and informative book "Is That a Fact?," Joe Schwarcz avers that pigs do not sweat and the saying "sweating like a pig" originates in iron smelting. Oblong pieces of hot iron, with a fancied resemblance to a sow with piglets, cool in sand to the dew point of the surrounding air, and hence water condenses on…

Efficacy improvement of a bioherbicidal fungus using a formulation-based approach

USDA-ARS?s Scientific Manuscript database

Greenhouse experiments were conducted to determine the effects of an invert (water - in - oil) emulsion (IE) on dew period duration and dew delay of Colletotrichum coccodes for biocontrol of the problematic weed, eastern black nightshade (Solanum ptycanthum). Dew periods of 4, 8, or 12 h provided ...

An early warning and control system for urban, drinking water quality protection: China's experience.

PubMed

Hou, Dibo; Song, Xiaoxuan; Zhang, Guangxin; Zhang, Hongjian; Loaiciga, Hugo

2013-07-01

An event-driven, urban, drinking water quality early warning and control system (DEWS) is proposed to cope with China's urgent need for protecting its urban drinking water. The DEWS has a web service structure and provides users with water quality monitoring functions, water quality early warning functions, and water quality accident decision-making functions. The DEWS functionality is guided by the principles of control theory and risk assessment as applied to the feedback control of urban water supply systems. The DEWS has been deployed in several large Chinese cities and found to perform well insofar as water quality early warning and emergency decision-making is concerned. This paper describes a DEWS for urban water quality protection that has been developed in China.

Transpiration Cooled Throat for Hydrocarbon Rocket Engines

DTIC Science & Technology

1991-12-01

entering the oxidizer circuit. Maximum dew point requirement was -500F. The purge pressure provided an oxidizer injector cold-flow pressure of 80 psia...energy bal- ance with the core gas is assumed wherein the heat flux to the annular liquid RP-I layer is equal’ 50 042 0 I- C3 I C30 ME1 M1 49 410 CI... gas generator mixture ratio MW molecular weight NASA/L.RC NASA Lewis Research Center NBP normal boiling point Ni chemical symbol for nickel nom

Validation and results of a scale model of dew deposition in urban environments

NASA Astrophysics Data System (ADS)

Richards, K.; Oke, T. R.

2002-12-01

There is growing interest in urban dew and its significance in questions of urban climate and air pollution deposition, but little research has been undertaken to study it. In this study, a generic, urban residential neighbourhood is modelled out-of-doors at a scale of 0.125, using three wooden houses (1.08 m tall), a concrete pavement (1.0 m in width), a grassed park (7.5 m in half-width) and several small trees (up to 1.5 m tall). The thermal inertia of each house is inflated, according to the internal thermal mass (ITM) approach, so that nocturnal surface temperatures are conserved. First-order validation was achieved through comparison with data collected at nearby full-scale sites in Vancouver, BC, Canada. Moisture accumulation (measured by blotting on grass and by lysimetry) is found to be primarily controlled by nocturnal weather conditions and the intrinsic nature of each substrate, e.g. dewfall is abundant on nights with few clouds and light winds, and on surfaces such as grass and asphalt-shingle roofs, which cool rapidly after sunset. However, these responses are modified by location effects related to the net radiation balance of the surface, which itself is strongly linked to site geometry as expressed by sky view factor and whether surfaces are isolated from heat sources. The dominant mechanism is argued to be the systematic increase in longwave radiation loss that is associated with increased sky view. Results agree with those observed at the full scale and suggest that maps of sky view factor, and knowledge of dew at an open site, can potentially be used to create maps of dew distribution in urban and other complex environments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The regional suitability of underground construction as a climate control technique is discussed with reference to (1) a bioclimatic analysis of long-term weather data for 29 locations in the United States to determine appropriate above ground climate control techniques, (2) a data base of synthesized ground temperatures for the coterminous United States, and (3) monthly dew point ground temperature comparisons for identifying the relative likelihood of condensation from one region to another. It is concluded that the suitability of earth tempering as a practice and of specific earth-sheltered design stereotypes varies geographically; while the subsurface almost always provides a thermalmore » advantage on its own terms when compared to above ground climatic data, it can, nonetheless, compromise the effectiveness of other, regionally more important climate control techniques. Also contained in the report are reviews of above and below ground climate mapping schemes related to human comfort and architectural design, and detailed description of a theoretical model of ground temperature, heat flow, and heat storage in the ground. Strategies of passive climate control are presented in a discussion of the building bioclimatic analysis procedure which has been applied in a computer analysis of 30 years of weather data for each of 29 locations in the United States.« less

Use of Satellite Data Assimilation to Infer Land Surface Thermal Inertia

NASA Technical Reports Server (NTRS)

Lapenta, William; McNider, Richard T.; Biazar, Arastoo; Suggs, Ron; Jedlovec, Gary; Dembek, Scott

2002-01-01

There are two important but observationally uncertain parameters in the grid averaged surface energy budgets of mesoscale models - surface moisture availability and thermal heat capacity. A technique has been successfully developed for assimilating Geostationary Operational Environmental Satellite (GOES) skin temperature tendencies during the mid-morning time frame to improve specification of surface moisture. In a new application of the technique, the use of satellite skin temperature tendencies in early evening is explored to improve specification of the surface thermal heat capacity. Together, these two satellite assimilation constraints have been shown to significantly improve the characterization of the surface energy budget of a mesoscale model on fine spatial scales. The GOES assimilation without the adjusted heat capacity was run operationally during the International H2O Project on a 12-km grid. This paper presents the results obtained when using both the moisture availability and heat capacity retrievals in concert. Preliminary results indicate that retrieved moisture availability alone improved the verification statistics of 2-meter temperature and dew point forecasts. Results from the 1.5 month long study period using the bulk heat capacity will be presented at the meeting.

Advancements, measurement uncertainties, and recent comparisons of the NOAA frost point hygrometer.

PubMed

Hall, Emrys G; Jordan, Allen F; Hurst, Dale F; Oltmans, Samuel J; Vömel, Holger; Kühnreich, Benjamin; Ebert, Volker

2016-01-01

The NOAA frost point hygrometer (FPH) is a balloon-borne instrument flown monthly at three sites to measure water vapor profiles up to 28 km. The FPH record from Boulder, Colorado, is the longest continuous stratospheric water vapor record. The instrument has an uncertainty in the stratosphere that is < 6 % and up to 12 % in the troposphere. A digital microcontroller version of the instrument improved upon the older versions in 2008 with sunlight filtering, better frost control, and resistance to radio frequency interference (RFI). A new thermistor calibration technique was implemented in 2014, decreasing the uncertainty in the thermistor calibration fit to less than 0.01 °C over the full range of frost - or dew point temperatures (-93 to +20 °C) measured during a profile. Results from multiple water vapor intercomparisons are presented, including the excellent agreement between the NOAA FPH and the direct tunable diode laser absorption spectrometer (dTDLAS) MC-PicT-1.4 during AquaVIT-2 chamber experiments over 6 days that provides confidence in the accuracy of the FPH measurements. Dual instrument flights with two FPHs or an FPH and a cryogenic frost point hygrometer (CFH) also show good agreement when launched on the same balloon. The results from these comparisons demonstrate the high level of accuracy of the NOAA FPH.

Influence of Gas Atmosphere Dew Point on the Selective Oxidation and the Reactive Wetting During Hot Dip Galvanizing of CMnSi TRIP Steel

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Lee, Seok Jae; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2013-01-01

The selective oxidation and reactive wetting of intercritically annealed Si-bearing CMnSi transformation-induced plasticity steels were investigated by high-resolution transmission electron microscopy. In a N2 + 10 pct H2 gas atmosphere with a dew point (DP) ranging from 213 K to 278 K (-60 °C to 5 °C), a continuous layer of selective oxides was formed on the surface. Annealing in a higher DP gas atmosphere resulted in a thinner layer of external oxidation and a greater depth of internal oxidation. The hot dipping was carried out in a Zn bath containing 0.22 mass pct Al, and the bath temperature was 733 K (460 °C). Coarse and discontinuous Fe2Al5- x Zn x grains and Fe-Zn intermetallics (ζ and δ) were observed at the steel/coating interface after the hot dip galvanizing (HDG) of panels were annealed in a low DP atmosphere 213 K (-60 °C). The Fe-Zn intermetallics were formed both in areas where the Fe2Al5- x Zn x inhibition layer had not been formed and on top of non-stoichiometric Fe-Al-Zn crystals. Poor wetting was observed on panels annealed in a low DP atmosphere because of the formation of thick film-type oxides on the surface. After annealing in higher DP gas atmospheres, i.e., 263 K and 278 K (-10 °C and 5 °C), a continuous and fine-grained Fe2Al5- x Zn x layer was formed. No Fe-Zn intermetallics were formed. The small grain size of the inhibition layer was attributed to the nucleation of the Fe2Al5- x Zn x grains on small ferrite sub-surface grains and the presence of granular surface oxides. A high DP atmosphere can therefore significantly contribute to the decrease of Zn-coating defects on CMnSi TRIP steels processed in HDG lines.

Influence of Gas Atmosphere Dew Point on the Galvannealing of CMnSi TRIP Steel

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2013-11-01

The Fe-Zn reaction occurring during the galvannealing of a Si-bearing transformation-induced plasticity (TRIP) steel was investigated by field-emission electron probe microanalysis and field-emission transmission electron microscopy. The galvannealing was simulated after hot dipping in a Zn bath containing 0.13 mass pct Al at 733 K (460 °C). The galvannealing temperature was in the range of 813 K to 843 K (540 °C to 570 °C). The kinetics and mechanism of the galvannealing reaction were strongly influenced by the gas atmosphere dew point (DP). After the galvannealing of a panel annealed in a N2+10 pct H2 gas atmosphere with low DPs [213 K and 243 K (-60 °C and -30 °C)], the coating layer consisted of δ (FeZn10) and η (Zn) phase crystals. The Mn-Si compound oxides formed during intercritical annealing were present mostly at the steel/coating interface after the galvannealing. Galvannealing of a panel annealed in higher DP [263 K and 273 K, and 278 K (-10 °C, 0 °C, and +5 °C)] gas atmospheres resulted in a coating layer consisting of δ and Г (Fe3Zn10) phase crystals, and a thin layer of Г 1 (Fe11Zn40) phase crystals at the steel/coating interface. The Mn-Si oxides were distributed homogeneously throughout the galvannealed (GA) coating layer. When the surface oxide layer thickness on panels annealed in a high DP gas atmosphere was reduced, the Fe content at the GA coating surface increased. Annealing in a higher DP gas atmosphere improved the coating quality of the GA panels because a thinner layer of oxides was formed. A high DP atmosphere can therefore significantly contribute to the suppression of Zn-alloy coating defects on CMnSi TRIP steel processed in hot dip galvanizing lines.

Complementary-relationship-based 30 year normals (1981-2010) of monthly latent heat fluxes across the contiguous United States

NASA Astrophysics Data System (ADS)

Szilagyi, Jozsef

2015-11-01

Thirty year normal (1981-2010) monthly latent heat fluxes (ET) over the conterminous United States were estimated by a modified Advection-Aridity model from North American Regional Reanalysis (NARR) radiation and wind as well as Parameter-Elevation Regressions on Independent Slopes Model (PRISM) air and dew-point temperature data. Mean annual ET values were calibrated with PRISM precipitation (P) and validated against United States Geological Survey runoff (Q) data. At the six-digit Hydrologic Unit Code level (sample size of 334) the estimated 30 year normal runoff (P - ET) had a bias of 18 mm yr-1, a root-mean-square error of 96 mm yr-1, and a linear correlation coefficient value of 0.95, making the estimates on par with the latest Land Surface Model results but without the need for soil and vegetation information or any soil moisture budgeting.

Development of a Model and Computer Code to Describe Solar Grade Silicon Production Processes

NASA Technical Reports Server (NTRS)

Srivastava, R.; Gould, R. K.

1979-01-01

The program aims at developing mathematical models and computer codes based on these models, which allow prediction of the product distribution in chemical reactors for converting gaseous silicon compounds to condensed-phase silicon. The major interest is in collecting silicon as a liquid on the reactor walls and other collection surfaces. Two reactor systems are of major interest, a SiCl4/Na reactor in which Si(l) is collected on the flow tube reactor walls and a reactor in which Si(l) droplets formed by the SiCl4/Na reaction are collected by a jet impingement method. During this quarter the following tasks were accomplished: (1) particle deposition routines were added to the boundary layer code; and (2) Si droplet sizes in SiCl4/Na reactors at temperatures below the dew point of Si are being calculated.

An experimental aluminum-fueled power plant

NASA Astrophysics Data System (ADS)

Vlaskin, M. S.; Shkolnikov, E. I.; Bersh, A. V.; Zhuk, A. Z.; Lisicyn, A. V.; Sorokovikov, A. I.; Pankina, Yu. V.

2011-10-01

An experimental co-generation power plant (CGPP-10) using aluminum micron powder (with average particle size up to 70 μm) as primary fuel and water as primary oxidant was developed and tested. Power plant can work in autonomous (unconnected from industrial network) nonstop regime producing hydrogen, electrical energy and heat. One of the key components of experimental plant is aluminum-water high-pressure reactor projected for hydrogen production rate of ∼10 nm3 h-1. Hydrogen from the reactor goes through condenser and dehumidifier and with -25 °C dew-point temperature enters into the air-hydrogen fuel cell 16 kW-battery. From 1 kg of aluminum the experimental plant produces 1 kWh of electrical energy and 5-7 kWh of heat. Power consumer gets about 10 kW of electrical power. Plant electrical and total efficiencies are 12% and 72%, respectively.

Short-term load forecasting using neural network for future smart grid application

NASA Astrophysics Data System (ADS)

Zennamo, Joseph Anthony, III

Short-term load forecasting of power system has been a classic problem for a long time. Not merely it has been researched extensively and intensively, but also a variety of forecasting methods has been raised. This thesis outlines some aspects and functions of smart meter. It also presents different policies and current statuses as well as future projects and objectives of SG development in several countries. Then the thesis compares main aspects about latest products of smart meter from different companies. Lastly, three types of prediction models are established in MATLAB to emulate the functions of smart grid in the short-term load forecasting, and then their results are compared and analyzed in terms of accuracy. For this thesis, more variables such as dew point temperature are used in the Neural Network model to achieve more accuracy for better short-term load forecasting results.

Spacecraft Crew Cabin Condensation Control

NASA Technical Reports Server (NTRS)

Carrillo, Laurie Y.; Rickman, Steven L.; Ungar, Eugene K.

2013-01-01

A report discusses a new technique to prevent condensation on the cabin walls of manned spacecraft exposed to the cold environment of space, as such condensation could lead to free water in the cabin. This could facilitate the growth of mold and bacteria, and could lead to oxidation and weakening of the cabin wall. This condensation control technique employs a passive method that uses spacecraft waste heat as the primary wallheating mechanism. A network of heat pipes is bonded to the crew cabin pressure vessel, as well as the pipes to each other, in order to provide for efficient heat transfer to the cabin walls and from one heat pipe to another. When properly sized, the heat-pipe network can maintain the crew cabin walls at a nearly uniform temperature. It can also accept and distribute spacecraft waste heat to maintain the pressure vessel above dew point.

A simple scaling approach to produce climate scenarios of local precipitation extremes for the Netherlands

NASA Astrophysics Data System (ADS)

Lenderink, Geert; Attema, Jisk

2015-08-01

Scenarios of future changes in small scale precipitation extremes for the Netherlands are presented. These scenarios are based on a new approach whereby changes in precipitation extremes are set proportional to the change in water vapor amount near the surface as measured by the 2m dew point temperature. This simple scaling framework allows the integration of information derived from: (i) observations, (ii) a new unprecedentedly large 16 member ensemble of simulations with the regional climate model RACMO2 driven by EC-Earth, and (iii) short term integrations with a non-hydrostatic model Harmonie. Scaling constants are based on subjective weighting (expert judgement) of the three different information sources taking also into account previously published work. In all scenarios local precipitation extremes increase with warming, yet with broad uncertainty ranges expressing incomplete knowledge of how convective clouds and the atmospheric mesoscale circulation will react to climate change.

Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System.

PubMed

Chen, Ling-Hsi; Chen, Chiachung

2018-02-21

Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories.

The Gonzaga desulfurization flue gas process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelleher, R.L.; O'Leary, T.J.; Shirk, I.A.

1984-01-01

The Gonzaga desulfurization flue gas process removes sulfur dioxide from a flue by cold water scrubbing. Sulfur dioxide is significantly more soluable in cold water (35/sup 0/F to 60/sup 0/F) than in warm water (100/sup 0/F). Sulfur dioxide reacts in water similarly as carbon dioxide reacts in water, in that both gasses are released from the water as the temperature of the water increases. The researchers at the Gonzaga University developed this process from the observations and techniques used in studying the acid and aldehyde concentrations in flue gasses with varying of fuel to air ratios. The apparatus was fixedmore » to a stationary engine and a gas/oil fired boiler. The flue gas was cooled to the dew point temperature of the air entering the combustion chamber on the pre-air heater. The system is described in two parts: the energies required for cooling in the scrubbing section and the energies required in the treatment section. The cold flue gas is utilized in cooling the scrubber section.« less

Uncertainly Analysis of Two Types of Humidity Sensors by a Humidity Generator with a Divided-Flow System

PubMed Central

Chen, Ling-Hsi

2018-01-01

Humidity measurement is an important technique for the agricultural, foods, pharmaceuticals, and chemical industries. For the sake of convenience, electrical relative humidity (RH) sensors have been widely used. These sensors need to be calibrated to ensure their accuracy and the uncertainty measurement of these sensors has become a major concern. In this study, a self-made divided-flow generator was established to calibrate two types of electrical humidity sensors. The standard reference humidity was calculated from dew-point temperature and air dry-bulb temperature measured by a chilled mirror monitor. This divided-flow generator could produce consistent result of RH measurement results. The uncertainty of the reference standard increased with the increase of RH values. The combined uncertainty with the adequate calibration equations were ranged from 0.82% to 1.45% RH for resistive humidity sensors and 0.63% to 1.4% for capacitive humidity sensors, respectively. This self-made, divided-flow generator, and calibration method are cheap, time-saving, and easy to be used. Thus, the proposed approach can easily be applied in research laboratories. PMID:29466313

Numerical analysis on centrifugal compressor with membrane type dryer

NASA Astrophysics Data System (ADS)

Razali, M. A.; Zulkafli, M. F.; Mat Isa, N.; Subari, Z.

2017-09-01

Moisture content is a common phenomenon in industrial processes especially in oil and gas industries. This contaminant has a lot of disadvantages which can lead to mechanical failure DEC (Deposition, Erosion & Corrosion) problems. To overcome DEC problem, this study proposed to design a centrifugal compressor with a membrane type dryer to reduce moisture content of a gas. The effectiveness of such design has been analyzed in this study using Computational Fluid Dynamics (CFD) approach. Numerical scheme based on multiphase flow technique is used in ANSYS Fluent software to evaluate the moisture content of the gas. Through this technique, two kind of centrifugal compressor, with and without membrane type dryer has been tested. The results show that the effects of pressure on dew point temperature of the gas change the composition of its moisture content, where high value lead more condensation to occur. However, with the injection of cool dry gas through membrane type dryer in the centrifugal compressor, the pressure and temperature of moisture content as well as mass fraction of H2O in centrifugal compressor show significant reduction.

Satellite based hydroclimatic understanding of evolution of Dengue and Zika virus

NASA Astrophysics Data System (ADS)

Khan, R.; Jutla, A.; Colwell, R. R.

2017-12-01

Vector-borne diseases are prevalent in tropical and subtropical regions especially in Africa, South America, and Asia. Vector eradication is perhaps not possible since pathogens adapt to local environment. In absence of appropriate vaccinations for Dengue and Zika virus, burden of these two infections continue to increase in several geographical locations. Aedes spp. is one of the major vectors for Dengue and Zika viruses. Etiologies on Dengue and Zika viruses are evolving, however the key question remains as to how one species of mosquito can transmit two different infections? We argue that a set of conducive environmental condition, modulated by regional climatic and weather processes, may lead to abundance of a specific virus. Using satellite based rainfall (TRMM/GPM), land surface temperature (MODIS) and dew point temperature (AIRS/MERRA), we have identified appropriate thresholds that can provide estimate on risk of abundance of Dengue or Zika viruses at least few weeks in advance. We will discuss a framework coupling satellite derived hydroclimatic and societal processes to predict environmental niches of favorability of conditions of Dengue or Zika risk in human population on a global scale.

NREL National Wind Technology Center (NWTC): M2 Tower; Boulder, Colorado (Data)

DOE Data Explorer

Jager, D.; Andreas, A.

1996-09-24

The National Wind Technology Center (NWTC), located at the foot of the Rocky Mountains near Boulder, Colorado, is a world-class research facility managed by NREL for the U.S. Department of Energy. NWTC researchers work with members of the wind energy industry to advance wind power technologies that lower the cost of wind energy through research and development of state-of-the-art wind turbine designs. NREL's Measurement and Instrument Data Center provides data from NWTC's M2 tower which are derived from instruments mounted on or near an 82 meter (270 foot) meteorological tower located at the western edge of the NWTC site and about 11 km (7 miles) west of Broomfield, and approximately 8 km (5 miles) south of Boulder, Colorado. The data represent the mean value of readings taken every two seconds and averaged over one minute. The wind speed and direction are measured at six heights on the tower and air temperature is measured at three heights. The dew point temperature, relative humidity, barometric pressure, totalized liquid precipitation, and global solar radiation are also available.

Urticaceae pollen concentration in the atmosphere of North Western Spain.

PubMed

Vega-Maray, Ana Maria; Valencia-Barrera, Rosa; Fernandez-Gonzalez, Delia; Fraile, Roberto

2003-01-01

Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.

Development of an inoculation technique and the evaluation of soybean genotypes for resistance to Coniothyrium glycines

USDA-ARS?s Scientific Manuscript database

A screening assay was developed for the pathogen Coniothyrium glycines which causes red leaf blotch of soybeans. We investigated the effects of inoculum density, temperature (20 and 25°C), and dew chamber incubation period (2-5 days) on disease expression in Williams 82 soybeans inoculated with C. g...

Recording dew gage

Treesearch

Merle G. Lloyd

1963-01-01

The instrument developed by Intermountain Forest and Range Experiment Station to record duration and amount of dew (fig. 1) consists of an expanded polystyrene block mounted on a balance, a clock-driven drum, and a pen geared from the balance to the drum. Changes in weight of the expanded polystyrene block as dew or rain is deposited are recorded on a chart mounted on...

Dew Point Evaporative Comfort Cooling

DTIC Science & Technology

2012-11-01

assisting with the installation of the data acquisition system and multiyear performance testing. Fort Carson engineers worked with the project...partners to design and integrate the Coolerado units into five facilities and designed an innovative rain water catchment system for four units at the...Theater. Mountain Energy Partnership provided invaluable assistance with the design and installation of the data acquisition system , as well as data

Avoid the Wet Basement Blues: Construction Methods Guarantee Success

ERIC Educational Resources Information Center

Domermuth, David

2006-01-01

A damp basement can be a nightmare, especially after mildew creates its eye-watering, nose-offending stench. There are two enemies to overcome: damp air condensing on interior walls and ground water penetrating the exterior. One can address condensation by drying or heating the air in a basement to raise it above the dew point. The simple way to…

Improving indoor air quality through the use of continual multipoint monitoring of carbon dioxide and dew point.

PubMed

Bearg, D W

1998-09-01

This article summarizes an approach for improving the indoor air quality (IAQ) in a building by providing feedback on the performance of the ventilation system. The delivery of adequate quantities of ventilation to all building occupants is necessary for the achievement of good IAQ. Feedback on the performance includes information on the adequacy of ventilation provided, the effectiveness of the distribution of this air, the adequacy of the duration of operation of the ventilation system, and the identification of leakage into the return plenum, either of outdoor or supply air. Keeping track of ventilation system performance is important not only in terms of maintaining good IAQ, but also making sure that this system continues to perform as intended after changes in building use. Information on the performance of the ventilation system is achieved by means of an automated sampling system that draws air from multiple locations and delivers it to both a carbon dioxide monitor and dew point sensor. The use of single shared sensors facilitates calibration checks as well as helps to guarantee data integrity. This approach to monitoring a building's ventilation system offers the possibility of achieving sustainable performance of this important aspect of good IAQ.

Effects of process variables in decarburization annealing of Fe-3%Si-0.3%C steel sheet on textures and magnetic properties

NASA Astrophysics Data System (ADS)

Park, Se Min; Koo, Yang Mo; Shim, Byoung Yul; Lee, Dong Nyung

2017-01-01

In Fe-3%Si-0.3%C steel sheet, a relatively strong <100>//ND texture can evolve in the surface layer through the α→γ→α phase transformation in relatively low vacuum (4 Pa) for an annealing time of 10 min and at a cooling rate of 20 K/s. Oxidation of the steel sheet surface prevents the evolution of the <100>//ND texture. However, vacuum-annealing under a vacuum pressure of 1.3×10-3 Pa causes decarburization of the steel sheet, which suppresses oxidation of the steel sheet surface, and subsequent annealing in wet hydrogen of 363 K in dew points causes a columnar grain structure with the <100>//ND texture. After the two-step-annealing (the vacuum annealing under a vacuum pressure of 1.3×10-3 Pa and subsequent decarburizing annealing in wet hydrogen of 363 K in dew points), the decarburized steel sheet exhibits good soft magnetic properties in NO with 3%Si, W15/50 (core loss at 1.5T and 50 Hz) = 2.47 W/kg and B50 (magnetic flux density at 5000 A/m) = 1.71 T.

Physical Patterns Associated with 27 April 2011 Tornado Outbreak

NASA Astrophysics Data System (ADS)

Ramos, Fernanda; Salem, Thomas

2012-02-01

The National Weather Service office in Memphis, Tennessee has aimed their efforts to improve severe tornado forecasting. Everything is not known about tornadogenesis, but one thing is: tornadoes tend to form within supercell thunderstorms. Hence, 27 April 2011 and 25 May 2011 were days when a Tornado Outbreak was expected to arise. Although 22 tornadoes struck the region on 27 April 2011, only 1 impacted the area on 25 May 2011. In order to understand both events, comparisons of their physical features were made. These parameters were studied using the Weather Event Simulator system and the NOAA/NWS Storm Prediction database. This research concentrated on the Surface Frontal Analysis, NAM40 700mb Dew-Points, NAM80 250mb Wind Speed and NAM20 500mb Vorticity images as well as 0-6 km Shear, MUCAPE and VGP mesoscale patterns. As result of this research a Dry-Line ahead of a Cold Front, Dew-points 5C and higher, and high Vorticity values^ were synoptic patterns that influenced to the formation of supercell tornadoes. Finally, MUCAPE and VGP favored the possibility of tornadoes occurrence on 25 May 2011, but shear was the factor that made 27 April 2011 a day for a Tornado Outbreak weather event.

Influence of temporal variations and climatic conditions on the physical and chemical characteristics of dew and rain in South-West Morocco

NASA Astrophysics Data System (ADS)

Lekouch, I.; Kabbachi, B.; Milimouk-Melnytchouk, I.; Muselli, M.; Beysens, D.

2010-07-01

In order to be used as alternative or supplemental sources of water, the physical and physico-chemical characteristics of rain, fog and dew water were investigated at Mirleft in the arid coastal environment of south-west Morocco. A site was instrumented on a terrace with a fog net collector, four 1 m2 inclined (30° ) test dew condenser, together with a weather station providing standard meteorological data. The study was carried out between May 1, 2007 and Avril 30, 2008. Over the one year period were noted 178 dew events (49% yearly occurrence), 31 rain events (8.5 % yearly occurrence) and 7 significant fog events (2 % yearly occurrence). The total quantity of collected water was 48.7 mm (rain), 18.9 mm (dew) and 1.4 mm (fog). Then collecting dew increases almost 40% the water yield although fog contributes to only 3%. A number of physico-chemical and biological parameters were also measured for dew and rain water: pH, electrical conductivity (EC), major anions (HCO3-,Cl-, SO42-,NO3-), major cations (NH4+, Na+, K+, Ca2+, Mg2+). It is found that the mean dew and rain pH are equal to 7.4 and 6.9, respectively and the mean EC are 730 ? S/cm and 316 ? S/cm, respectively, corresponding to large total mineralization. The ratio TA/TC < 1 indicates the alkaline nature of dew and rain water. The analysis of the major ions shows that the concentration of Cl- and Na+ is high compared to that of the other elements. To consider the marine and nonmarine origin of these ions, the fraction of salt coming from sea (SSF) was also calculated. While in dew Cl-, Na+ et Mg2+ are clearly of marine origine, the small SSF value for Ca2+, K+, SO4- et NO3- in dew suggests a considerable contribution of nonmarine origin for these components. In contrast, in rainwater, the values of the No Sea Salt Fraction (NSSF) indicates that only Ca2+ et NO3-are of non marine origin. The dry and transition seasons (spring, summer, fall) correspond to a water more concentrated in elements than during the wet season (winter), in relation to the water yield. The ions concentration agrees with the World Health Organization requirements for potable water. The biological analysis shows harmless vegetal spores and little contamination by animal/human bacteria.

Analytically based photon scatter modeling for a multipinhole cardiac SPECT camera.

PubMed

Pourmoghaddas, Amir; Wells, R Glenn

2016-11-01

Dedicated cardiac SPECT scanners have improved performance over standard gamma cameras allowing reductions in acquisition times and/or injected activity. One approach to improving performance has been to use pinhole collimators, but this can cause position-dependent variations in attenuation, sensitivity, and spatial resolution. CT attenuation correction (AC) and an accurate system model can compensate for many of these effects; however, scatter correction (SC) remains an outstanding issue. In addition, in cameras using cadmium-zinc-telluride-based detectors, a large portion of unscattered photons is detected with reduced energy (low-energy tail). Consequently, application of energy-based SC approaches in these cameras leads to a higher increase in noise than with standard cameras due to the subtraction of true counts detected in the low-energy tail. Model-based approaches with parallel-hole collimator systems accurately calculate scatter based on the physics of photon interactions in the patient and camera and generate lower-noise estimates of scatter than energy-based SC. In this study, the accuracy of a model-based SC method was assessed using physical phantom studies on the GE-Discovery NM530c and its performance was compared to a dual energy window (DEW)-SC method. The analytical photon distribution (APD) method was used to calculate the distribution of probabilities that emitted photons will scatter in the surrounding scattering medium and be subsequently detected. APD scatter calculations for 99m Tc-SPECT (140 ± 14 keV) were validated with point-source measurements and 15 anthropomorphic cardiac-torso phantom experiments and varying levels of extra-cardiac activity causing scatter inside the heart. The activity inserted into the myocardial compartment of the phantom was first measured using a dose calibrator. CT images were acquired on an Infinia Hawkeye (GE Healthcare) SPECT/CT and coregistered with emission data for AC. For comparison, DEW scatter projections (120 ± 6 keV ) were also extracted from the acquired list-mode SPECT data. Either APD or DEW scatter projections were subtracted from corresponding 140 keV measured projections and then reconstructed with AC (APD-SC and DEW-SC). Quantitative accuracy of the activity measured in the heart for the APD-SC and DEW-SC images was assessed against dose calibrator measurements. The difference between modeled and acquired projections was measured as the root-mean-squared-error (RMSE). APD-modeled projections for a clinical cardiac study were also evaluated. APD-modeled projections showed good agreement with SPECT measurements and had reduced noise compared to DEW scatter estimates. APD-SC reduced mean error in activity measurement compared to DEW-SC in images and the reduction was statistically significant where the scatter fraction (SF) was large (mean SF = 28.5%, T-test p = 0.007). APD-SC reduced measurement uncertainties as well; however, the difference was not found to be statistically significant (F-test p > 0.5). RMSE comparisons showed that elevated levels of scatter did not significantly contribute to a change in RMSE (p > 0.2). Model-based APD scatter estimation is feasible for dedicated cardiac SPECT scanners with pinhole collimators. APD-SC images performed better than DEW-SC images and improved the accuracy of activity measurement in high-scatter scenarios.

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon

NASA Astrophysics Data System (ADS)

da Silva, Jamile Andréa Rodrigues; de Araújo, Airton Alencar; Lourenço Júnior, José de Brito; dos Santos, Núbia de Fátima Alves; Garcia, Alexandre Rossetto; de Oliveira, Raimundo Parente

2015-09-01

The study aimed to develop new and more specific thermal comfort indices for buffaloes reared in the Amazon region. Twenty female Murrah buffaloes were studied for a year. The animals were fed in pasture with drinking water and mineral supplementation ad libitum. The following parameters were measured twice a week in the morning (7 AM) and afternoon (1 PM): air temperature (AT), relative air humidity (RH), dew point temperature (DPT), wet bulb temperature (WBT), black globe temperature (BGT), rectal temperature (RT), respiratory rate (RR), and body surface temperature (BST). The temperature and humidity index (THI), globe temperature and humidity index (GTHI), Benezra's comfort index (BTCI), and Ibéria's heat tolerance index (IHTI) were calculated so they could be compared to the new indices. Multivariate regression analyses were carried out using the canonical correlation model, and all indices were correlated with the physiological and climatic variables. Three pairs of indices (general, effective, and practical) were determined comprising the buffalo comfort climatic condition index (BCCCI) and the buffalo environmental comfort index (BECI). The indices were validated and a great agreement was found among the BCCCIs (general, effective, and practical), with 98.3 % between general and effective a.nd 92.6 % between general and practical. A significant correlation ( P < 0.01) was found between the new indices and the physiological and climatic variables, which indicated that these may be used in pairs to diagnose thermal stress in buffaloes reared in the Amazon.

Thermal comfort indices of female Murrah buffaloes reared in the Eastern Amazon.

PubMed

da Silva, Jamile Andréa Rodrigues; de Araújo, Airton Alencar; Lourenço Júnior, José de Brito; dos Santos, Núbia de Fátima Alves; Garcia, Alexandre Rossetto; de Oliveira, Raimundo Parente

2015-09-01

The study aimed to develop new and more specific thermal comfort indices for buffaloes reared in the Amazon region. Twenty female Murrah buffaloes were studied for a year. The animals were fed in pasture with drinking water and mineral supplementation ad libitum. The following parameters were measured twice a week in the morning (7 AM) and afternoon (1 PM): air temperature (AT), relative air humidity (RH), dew point temperature (DPT), wet bulb temperature (WBT), black globe temperature (BGT), rectal temperature (RT), respiratory rate (RR), and body surface temperature (BST). The temperature and humidity index (THI), globe temperature and humidity index (GTHI), Benezra's comfort index (BTCI), and Ibéria's heat tolerance index (IHTI) were calculated so they could be compared to the new indices. Multivariate regression analyses were carried out using the canonical correlation model, and all indices were correlated with the physiological and climatic variables. Three pairs of indices (general, effective, and practical) were determined comprising the buffalo comfort climatic condition index (BCCCI) and the buffalo environmental comfort index (BECI). The indices were validated and a great agreement was found among the BCCCIs (general, effective, and practical), with 98.3 % between general and effective a.nd 92.6 % between general and practical. A significant correlation (P < 0.01) was found between the new indices and the physiological and climatic variables, which indicated that these may be used in pairs to diagnose thermal stress in buffaloes reared in the Amazon.

Six hydrophobins are involved in hydrophobin rodlet formation in Aspergillus nidulans and contribute to hydrophobicity of the spore surface.

PubMed

Grünbacher, André; Throm, Tanja; Seidel, Constanze; Gutt, Beatrice; Röhrig, Julian; Strunk, Timo; Vincze, Paul; Walheim, Stefan; Schimmel, Thomas; Wenzel, Wolfgang; Fischer, Reinhard

2014-01-01

Hydrophobins are amphiphilic proteins able to self-assemble at water-air interphases and are only found in filamentous fungi. In Aspergillus nidulans two hydrophobins, RodA and DewA, have been characterized, which both localize on the conidiospore surface and contribute to its hydrophobicity. RodA is the constituent protein of very regularly arranged rodlets, 10 nm in diameter. Here we analyzed four more hydrophobins, DewB-E, in A. nidulans and found that all six hydrophobins contribute to the hydrophobic surface of the conidiospores but only deletion of rodA caused loss of the rodlet structure. Analysis of the rodlets in the dewB-E deletion strains with atomic force microscopy revealed that the rodlets appeared less robust. Expression of DewA and DewB driven from the rodA promoter and secreted with the RodA secretion signal in a strain lacking RodA, restored partly the hydrophobicity. DewA and B were able to form rodlets to some extent but never reached the rodlet structure of RodA. The rodlet-lacking rodA-deletion strain opens the possibility to systematically study rodlet formation of other natural or synthetic hydrophobins.

Six Hydrophobins Are Involved in Hydrophobin Rodlet Formation in Aspergillus nidulans and Contribute to Hydrophobicity of the Spore Surface

PubMed Central

Seidel, Constanze; Gutt, Beatrice; Röhrig, Julian; Strunk, Timo; Vincze, Paul; Walheim, Stefan; Schimmel, Thomas; Wenzel, Wolfgang; Fischer, Reinhard

2014-01-01

Hydrophobins are amphiphilic proteins able to self-assemble at water-air interphases and are only found in filamentous fungi. In Aspergillus nidulans two hydrophobins, RodA and DewA, have been characterized, which both localize on the conidiospore surface and contribute to its hydrophobicity. RodA is the constituent protein of very regularly arranged rodlets, 10 nm in diameter. Here we analyzed four more hydrophobins, DewB-E, in A. nidulans and found that all six hydrophobins contribute to the hydrophobic surface of the conidiospores but only deletion of rodA caused loss of the rodlet structure. Analysis of the rodlets in the dewB-E deletion strains with atomic force microscopy revealed that the rodlets appeared less robust. Expression of DewA and DewB driven from the rodA promoter and secreted with the RodA secretion signal in a strain lacking RodA, restored partly the hydrophobicity. DewA and B were able to form rodlets to some extent but never reached the rodlet structure of RodA. The rodlet-lacking rodA-deletion strain opens the possibility to systematically study rodlet formation of other natural or synthetic hydrophobins. PMID:24722460

Modeling daily soil temperature over diverse climate conditions in Iran—a comparison of multiple linear regression and support vector regression techniques

NASA Astrophysics Data System (ADS)

Delbari, Masoomeh; Sharifazari, Salman; Mohammadi, Ehsan

2018-02-01

The knowledge of soil temperature at different depths is important for agricultural industry and for understanding climate change. The aim of this study is to evaluate the performance of a support vector regression (SVR)-based model in estimating daily soil temperature at 10, 30 and 100 cm depth at different climate conditions over Iran. The obtained results were compared to those obtained from a more classical multiple linear regression (MLR) model. The correlation sensitivity for the input combinations and periodicity effect were also investigated. Climatic data used as inputs to the models were minimum and maximum air temperature, solar radiation, relative humidity, dew point, and the atmospheric pressure (reduced to see level), collected from five synoptic stations Kerman, Ahvaz, Tabriz, Saghez, and Rasht located respectively in the hyper-arid, arid, semi-arid, Mediterranean, and hyper-humid climate conditions. According to the results, the performance of both MLR and SVR models was quite well at surface layer, i.e., 10-cm depth. However, SVR performed better than MLR in estimating soil temperature at deeper layers especially 100 cm depth. Moreover, both models performed better in humid climate condition than arid and hyper-arid areas. Further, adding a periodicity component into the modeling process considerably improved the models' performance especially in the case of SVR.

Searching for the best modeling specification for assessing the effects of temperature and humidity on health: a time series analysis in three European cities.

PubMed

Rodopoulou, Sophia; Samoli, Evangelia; Analitis, Antonis; Atkinson, Richard W; de'Donato, Francesca K; Katsouyanni, Klea

2015-11-01

Epidemiological time series studies suggest daily temperature and humidity are associated with adverse health effects including increased mortality and hospital admissions. However, there is no consensus over which metric or lag best describes the relationships. We investigated which temperature and humidity model specification most adequately predicted mortality in three large European cities. Daily counts of all-cause mortality, minimum, maximum and mean temperature and relative humidity and apparent temperature (a composite measure of ambient and dew point temperature) were assembled for Athens, London, and Rome for 6 years between 1999 and 2005. City-specific Poisson regression models were fitted separately for warm (April-September) and cold (October-March) periods adjusting for seasonality, air pollution, and public holidays. We investigated goodness of model fit for each metric for delayed effects up to 13 days using three model fit criteria: sum of the partial autocorrelation function, AIC, and GCV. No uniformly best index for all cities and seasonal periods was observed. The effects of temperature were uniformly shown to be more prolonged during cold periods and the majority of models suggested separate temperature and humidity variables performed better than apparent temperature in predicting mortality. Our study suggests that the nature of the effects of temperature and humidity on mortality vary between cities for unknown reasons which require further investigation but may relate to city-specific population, socioeconomic, and environmental characteristics. This may have consequences on epidemiological studies and local temperature-related warning systems.

Searching for the best modeling specification for assessing the effects of temperature and humidity on health: a time series analysis in three European cities

NASA Astrophysics Data System (ADS)

Rodopoulou, Sophia; Samoli, Evangelia; Analitis, Antonis; Atkinson, Richard W.; de'Donato, Francesca K.; Katsouyanni, Klea

2015-11-01

Epidemiological time series studies suggest daily temperature and humidity are associated with adverse health effects including increased mortality and hospital admissions. However, there is no consensus over which metric or lag best describes the relationships. We investigated which temperature and humidity model specification most adequately predicted mortality in three large European cities. Daily counts of all-cause mortality, minimum, maximum and mean temperature and relative humidity and apparent temperature (a composite measure of ambient and dew point temperature) were assembled for Athens, London, and Rome for 6 years between 1999 and 2005. City-specific Poisson regression models were fitted separately for warm (April-September) and cold (October-March) periods adjusting for seasonality, air pollution, and public holidays. We investigated goodness of model fit for each metric for delayed effects up to 13 days using three model fit criteria: sum of the partial autocorrelation function, AIC, and GCV. No uniformly best index for all cities and seasonal periods was observed. The effects of temperature were uniformly shown to be more prolonged during cold periods and the majority of models suggested separate temperature and humidity variables performed better than apparent temperature in predicting mortality. Our study suggests that the nature of the effects of temperature and humidity on mortality vary between cities for unknown reasons which require further investigation but may relate to city-specific population, socioeconomic, and environmental characteristics. This may have consequences on epidemiological studies and local temperature-related warning systems.

Design and Applications of a Climatic Chamber for in-situ Neutron Imaging Experiments

NASA Astrophysics Data System (ADS)

Mannes, David; Schmid, Florian; Wehmann, Timon; Lehmann, Eberhard

Due to the high sensitivity for hydrogen, the detection and quantification of moisture and moisture transport processes are some of the key topics in neutron imaging. Especially when dealing with hygroscopic material, such as wood and other porous media, it is crucial for quantitative analyses to know and control the ambient conditions of the sample precisely. In this work, a neutron transparent climatic chamber is presented, which was designed and built for the imaging facilities at the Paul Scherrer Institut (PSI), Villigen (CH). The air-conditioned measuring system consists of the actual sample chamber and a moisture generator providing air with adjustable temperature and relative humidity (%RH) (up to a dew point temperature of 70 °C). The two components are connected with a flexible tube, which features insulation, a heating system and temperature sensors to prevent condensation within the tube. The sample chamber itself is equipped with neutron transparent windows, insulating double walls with three feed-through openings for the rotation stage, sensors for humidity and temperature. Thermoelectric modules allow to control the chamber temperature in the range of -20 °C to 100 °C. The chamber allows to control the climatic conditions either in a static mode (stable temperature and %RH) or in dynamic mode (humidity or temperature cycles). The envisaged areas of application are neutron radiography and tomography investigations of dynamic processes in building materials (e.g. wood, concrete), food science and any other application necessitating the control of the climatic conditions.

A systematic approach to determining the properties of an iodine absorption cell for high-precision radial velocity measurements

NASA Astrophysics Data System (ADS)

Perdelwitz, V.; Huke, P.

2018-06-01

Absorption cells filled with diatomic iodine are frequently employed as wavelength reference for high-precision stellar radial velocity determination due their long-term stability and low cost. Despite their wide-spread usage in the community, there is little documentation on how to determine the ideal operating temperature of an individual cell. We have developed a new approach to measuring the effective molecular temperature inside a gas absorption cell and searching for effects detrimental to a high precision wavelength reference, utilizing the Boltzmann distribution of relative line depths within absorption bands of single vibrational transitions. With a high resolution Fourier transform spectrometer, we took a series of 632 spectra at temperatures between 23 °C and 66 °C. These spectra provide a sufficient basis to test the algorithm and demonstrate the stability and repeatability of the temperature determination via molecular lines on a single iodine absorption cell. The achievable radial velocity precision σRV is found to be independent of the cell temperature and a detailed analysis shows a wavelength dependency, which originates in the resolving power of the spectrometer in use and the signal-to-noise ratio. Two effects were found to cause apparent absolute shifts in radial velocity, a temperature-induced shift of the order of ˜1 ms-1K-1 and a more significant effect resulting in abrupt jumps of ≥50 ms-1 is determined to be caused by the temperature crossing the dew point of the molecular iodine.

A physically based analytical spatial air temperature and humidity model

NASA Astrophysics Data System (ADS)

Yang, Yang; Endreny, Theodore A.; Nowak, David J.

2013-09-01

Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the same mesoscale climate, grid air temperature and humidity are modified by local variation in absorbed solar radiation and the partitioning of sensible and latent heat. The model uses a reference grid site for time series meteorological data and the air temperature and humidity of any other grid can be obtained by solving the heat flux network equations. PASATH was coupled with the USDA iTree-Hydro water balance model to obtain evapotranspiration terms and run from 20 to 29 August 2010 at a 360 m by 360 m grid scale and hourly time step across a 285 km2 watershed including the urban area of Syracuse, NY. PASATH predictions were tested at nine urban weather stations representing variability in urban topography and land cover. The PASATH model predictive efficiency R2 ranged from 0.81 to 0.99 for air temperature and 0.77 to 0.97 for dew point temperature. PASATH is expected to have broad applications on environmental and ecological models.

Field Comparison between Sling Psychrometer and Meteorological Measuring Set AN/TMQ-22

DTIC Science & Technology

the ML-224 Sling Psychrometer . From a series of independent tests designed to minimize error it was concluded that the AN/TMQ-22 yielded a more accurate...dew point reading. The average relative humidity error using the sling psychrometer was +9% while the AN/TMQ-22 had a plus or minus 2% error. Even with cautious measurement the sling yielded a +4% error.

NAVFAC Ocean Thermal Energy Conversion (OTEC) Project; OTEC System Design Report

DTIC Science & Technology

2010-11-16

191 Figure 3-129. Web illustration of a magnetically coupled pump ...............................................192 Figure 3-130...utility air at a suitable water dew point. Two 100% capacity rotary screw compressors, dryer and receiver shall be installed to serve process and...remora centerline, with positive TCG out of the paper and negative TCG into the paper . The CG of the remora in its vertical orientation is

Ethics, Interpretation, and Pedagogy: Martin Buber and the Undergraduate Literature Classroom

ERIC Educational Resources Information Center

Dew, Spencer

2007-01-01

Martin Buber, widely recognized as a philosopher and theologian, frequently lauded as a prophet, said at a celebration of his 80th birthday, "I am no philosopher, prophet, or theologian. I am simply a man who has seen something and who goes to a window and points to what he has seen." In this article, Spencer Dew calls that statement a…

Comparing daily temperature averaging methods: the role of surface and atmosphere variables in determining spatial and seasonal variability

NASA Astrophysics Data System (ADS)

Bernhardt, Jase; Carleton, Andrew M.

2018-05-01

The two main methods for determining the average daily near-surface air temperature, twice-daily averaging (i.e., [Tmax+Tmin]/2) and hourly averaging (i.e., the average of 24 hourly temperature measurements), typically show differences associated with the asymmetry of the daily temperature curve. To quantify the relative influence of several land surface and atmosphere variables on the two temperature averaging methods, we correlate data for 215 weather stations across the Contiguous United States (CONUS) for the period 1981-2010 with the differences between the two temperature-averaging methods. The variables are land use-land cover (LULC) type, soil moisture, snow cover, cloud cover, atmospheric moisture (i.e., specific humidity, dew point temperature), and precipitation. Multiple linear regression models explain the spatial and monthly variations in the difference between the two temperature-averaging methods. We find statistically significant correlations between both the land surface and atmosphere variables studied with the difference between temperature-averaging methods, especially for the extreme (i.e., summer, winter) seasons (adjusted R2 > 0.50). Models considering stations with certain LULC types, particularly forest and developed land, have adjusted R2 values > 0.70, indicating that both surface and atmosphere variables control the daily temperature curve and its asymmetry. This study improves our understanding of the role of surface and near-surface conditions in modifying thermal climates of the CONUS for a wide range of environments, and their likely importance as anthropogenic forcings—notably LULC changes and greenhouse gas emissions—continues.

Pollutant deposition via dew in urban and rural environment, Cracow, Poland

NASA Astrophysics Data System (ADS)

Muskała, Piotr; Sobik, Mieczysław; Błaś, Marek; Polkowska, Żaneta; Bokwa, Anita

2015-01-01

This study is a comparative analysis of dew in rural and urban environment. Dew samples were collected between May and October, 2009 in two reference stations in southern Poland: Cracow and Gaik-Brzezowa. The investigation included comparison of volume and chemistry of the collected samples. Due to its formation mechanisms, dew is a good indicator of air pollution. Following parameters were analyzed in 159 collected samples: pH, electric conductivity, concentration of formaldehyde and phenols, concentration of NH4+, Ca2 +, K+, Na+, and Mg2 + cations and NO2-, NO3-, SO42 -, Cl-, F-, and PO43 - anions. The frequency of dew was approximately the same, both in urban and rural conditions reaching 43% of the measurement period. Dew intensity, expressed by volume, was on average two times larger in rural environment than in urban conditions. Urban landuse was recognized as the main factor reducing dew intensity in the urban station in comparison to the rural. Furthermore, the intensity of dew depended on synoptic scale air circulation at both measurement sites. As expected, samples collected in Cracow were much more polluted than the ones from Gaik-Brzezowa. The average TIC (Total Ionic Content) parameter was approximately 50% higher at the urban station. The pH in the rural station was more acidic. NO3- anions and Ca2 + cations were predominant in both measurement sites, however the participation of Ca2 + in Cracow was higher. NO3- indicates pollutions emitted by transport and industrial sources. The concentration of the analytes in both stations, as the volume, depended on air circulation direction. For Gaik-Brzezowa the highest TIC was observed mainly within southern circulation, while for Cracow the highest TIC was noted within both northern and southern. In general the rural station represented background pollution for the whole region and the pollution in Cracow was more dependent on local urban sources as transport or industry.

Advancements, measurement uncertainties, and recent comparisons of the NOAA frost point hygrometer

PubMed Central

Hall, Emrys G.; Jordan, Allen F.; Hurst, Dale F.; Oltmans, Samuel J.; Vömel, Holger; Kühnreich, Benjamin; Ebert, Volker

2017-01-01

The NOAA frost point hygrometer (FPH) is a balloon-borne instrument flown monthly at three sites to measure water vapor profiles up to 28 km. The FPH record from Boulder, Colorado, is the longest continuous stratospheric water vapor record. The instrument has an uncertainty in the stratosphere that is < 6 % and up to 12 % in the troposphere. A digital microcontroller version of the instrument improved upon the older versions in 2008 with sunlight filtering, better frost control, and resistance to radio frequency interference (RFI). A new thermistor calibration technique was implemented in 2014, decreasing the uncertainty in the thermistor calibration fit to less than 0.01 °C over the full range of frost – or dew point temperatures (−93 to +20 °C) measured during a profile. Results from multiple water vapor intercomparisons are presented, including the excellent agreement between the NOAA FPH and the direct tunable diode laser absorption spectrometer (dTDLAS) MC-PicT-1.4 during AquaVIT-2 chamber experiments over 6 days that provides confidence in the accuracy of the FPH measurements. Dual instrument flights with two FPHs or an FPH and a cryogenic frost point hygrometer (CFH) also show good agreement when launched on the same balloon. The results from these comparisons demonstrate the high level of accuracy of the NOAA FPH. PMID:28845201

Some mechanisms for the formation of octopus-shaped iron micro-particles

NASA Astrophysics Data System (ADS)

Bica, Ioan

2004-08-01

Fluid spheres (micro-spheres or/and drops) are formed out of the metallic solid (the carbon steel semi-finished product) in the argon plasma of the transferred electric arc. For short intervals of time, the spheres are at rest with relation to vapors. The movement of the vapors around the spheres is in the same plane. It consists of a movement around a circle combined with the movement produced by a definitely located whirl. The molar concentration of the vapors is small in comparison with the molar density of the mixture formed of vapors and gas. At the intersection of the sphere and the plane of movement of the vapors, distinct stagnation point is formed. They constitute points of the beginning/and end of the current lines. Each current line is a carrier of a vapor cylinder. In time, the cylinder-gas interface reaches points of temperature equal to that of the "dew point" for iron. On this occasion a liquid membrane is formed. It delimits the vapor-gas mixture from the rest of the gas. Subsequent to the process of diffusion in non-stationary condition, the membrane becomes thicker and no vapors exist inside the tube. Needle-shaped micro-tubes are formed, in liquid phase, around the fluid sphere. By solidification, micro-particles occur, consisting of a central nucleus around which ligaments branch out.

Artificial Intelligence Techniques for Predicting and Mapping Daily Pan Evaporation

NASA Astrophysics Data System (ADS)

Arunkumar, R.; Jothiprakash, V.; Sharma, Kirty

2017-09-01

In this study, Artificial Intelligence techniques such as Artificial Neural Network (ANN), Model Tree (MT) and Genetic Programming (GP) are used to develop daily pan evaporation time-series (TS) prediction and cause-effect (CE) mapping models. Ten years of observed daily meteorological data such as maximum temperature, minimum temperature, relative humidity, sunshine hours, dew point temperature and pan evaporation are used for developing the models. For each technique, several models are developed by changing the number of inputs and other model parameters. The performance of each model is evaluated using standard statistical measures such as Mean Square Error, Mean Absolute Error, Normalized Mean Square Error and correlation coefficient (R). The results showed that daily TS-GP (4) model predicted better with a correlation coefficient of 0.959 than other TS models. Among various CE models, CE-ANN (6-10-1) resulted better than MT and GP models with a correlation coefficient of 0.881. Because of the complex non-linear inter-relationship among various meteorological variables, CE mapping models could not achieve the performance of TS models. From this study, it was found that GP performs better for recognizing single pattern (time series modelling), whereas ANN is better for modelling multiple patterns (cause-effect modelling) in the data.

Intelligent Chilled Mirror Humidity Sensor

DTIC Science & Technology

1988-12-01

measure- ments made 8 times each day (roughly 3000 measurements). 3. Accuracy of a dew point measurement is to be within 0.50C. Some means for warning of...unreliable and was eventually discarded from the tests. As a replacement, we chose a manually operated sling psychrometer (Assman Corp.) which, though...electronically to lengthen the useful time that measurements can be made between cleanings. Once the mirror becomes ex- cessively dirty, further

Low Relative Humidity in the Atmosphere

DTIC Science & Technology

1989-01-01

occur [1]. Dew points in most standard metrorological data are calculated from measurements with psychrometers to determine wet-bulb and dry-bulb...variation existed in relation to the observed data during the day. Only one entire day was missing, and an interpolation was made between the...few sporadic reports at other hours. No attempt has been made to interpolate missing observations as was done for Yuma. Because of the large number of

Uncertainty Evaluation of the New Setup for Measurement of Water-Vapor Permeation Rate by a Dew-Point Sensor

NASA Astrophysics Data System (ADS)

Hudoklin, D.; Šetina, J.; Drnovšek, J.

2012-09-01

The measurement of the water-vapor permeation rate (WVPR) through materials is very important in many industrial applications such as the development of new fabrics and construction materials, in the semiconductor industry, packaging, vacuum techniques, etc. The demand for this kind of measurement grows considerably and thus many different methods for measuring the WVPR are developed and standardized within numerous national and international standards. However, comparison of existing methods shows a low level of mutual agreement. The objective of this paper is to demonstrate the necessary uncertainty evaluation for WVPR measurements, so as to provide a basis for development of a corresponding reference measurement standard. This paper presents a specially developed measurement setup, which employs a precision dew-point sensor for WVPR measurements on specimens of different shapes. The paper also presents a physical model, which tries to account for both dynamic and quasi-static methods, the common types of WVPR measurements referred to in standards and scientific publications. An uncertainty evaluation carried out according to the ISO/IEC guide to the expression of uncertainty in measurement (GUM) shows the relative expanded ( k = 2) uncertainty to be 3.0 % for WVPR of 6.71 mg . h-1 (corresponding to permeance of 30.4 mg . m-2. day-1 . hPa-1).

Performance of operational radiosonde humidity sensors in direct comparison with a chilled mirror dew-point hygrometer and its climate implication

NASA Astrophysics Data System (ADS)

Wang, Junhong; Carlson, David J.; Parsons, David B.; Hock, Terrence F.; Lauritsen, Dean; Cole, Harold L.; Beierle, Kathryn; Chamberlain, Edward

2003-08-01

This study evaluates performance of humidity sensors in two widely used operational radiosondes, Vaisala and Sippican (formally VIZ), in comparison with a research quality, and potentially more accurate, chilled mirror dew-point hygrometer named ``Snow White''. A research radiosonde system carrying the Snow White (SW) hygrometer was deployed in the Oklahoma panhandle and at Dodge City, KS during the International H2O Project (IHOP_2002). A total of sixteen sondes were launched with either Vaisala RS80 or Sippican VIZ-B2 radiosondes on the same balloons. Comparisons of humidity data from the SW with Vaisala and Sippican data show that (a) Vaisala RS80-H agrees with the SW very well in the middle and lower troposphere, but has dry biases in the upper troposphere (UT), (b) Sippican carbon hygristor (CH) has time-lag errors throughout the troposphere and fails to respond to humidity changes in the UT, sometimes even in the middle troposphere, and (c) the SW can detect cirrus clouds near the tropopause and possibly estimate their ice water content (IWC). The failure of CH in the UT results in significant and artificial humidity shifts in radiosonde climate records at stations where a transition from VIZ to Vaisala radiosondes has occurred.

Time-series Analysis of Heat Waves and Emergency Department Visits in Atlanta, 1993 to 2012

PubMed Central

Chen, Tianqi; Sarnat, Stefanie E.; Grundstein, Andrew J.; Winquist, Andrea

2017-01-01

Background: Heat waves are extreme weather events that have been associated with adverse health outcomes. However, there is limited knowledge of heat waves’ impact on population morbidity, such as emergency department (ED) visits. Objectives: We investigated associations between heat waves and ED visits for 17 outcomes in Atlanta over a 20-year period, 1993–2012. Methods: Associations were estimated using Poisson log-linear models controlling for continuous air temperature, dew-point temperature, day of week, holidays, and time trends. We defined heat waves as periods of ≥2 consecutive days with temperatures beyond the 98th percentile of the temperature distribution over the period from 1945–2012. We considered six heat wave definitions using maximum, minimum, and average air temperatures and apparent temperatures. Associations by heat wave characteristics were examined. Results: Among all outcome-heat wave combinations, associations were strongest between ED visits for acute renal failure and heat waves defined by maximum apparent temperature at lag 0 [relative risk (RR) = 1.15; 95% confidence interval (CI): 1.03–1.29], ED visits for ischemic stroke and heat waves defined by minimum temperature at lag 0 (RR = 1.09; 95% CI: 1.02–1.17), and ED visits for intestinal infection and heat waves defined by average temperature at lag 1 (RR = 1.10; 95% CI: 1.00–1.21). ED visits for all internal causes were associated with heat waves defined by maximum temperature at lag 1 (RR = 1.02; 95% CI: 1.00, 1.04). Conclusions: Heat waves can confer additional risks of ED visits beyond those of daily air temperature, even in a region with high air-conditioning prevalence. https://doi.org/10.1289/EHP44 PMID:28599264

Time-series Analysis of Heat Waves and Emergency Department Visits in Atlanta, 1993 to 2012.

PubMed

Chen, Tianqi; Sarnat, Stefanie E; Grundstein, Andrew J; Winquist, Andrea; Chang, Howard H

2017-05-31

Heat waves are extreme weather events that have been associated with adverse health outcomes. However, there is limited knowledge of heat waves' impact on population morbidity, such as emergency department (ED) visits. We investigated associations between heat waves and ED visits for 17 outcomes in Atlanta over a 20-year period, 1993-2012. Associations were estimated using Poisson log-linear models controlling for continuous air temperature, dew-point temperature, day of week, holidays, and time trends. We defined heat waves as periods of consecutive days with temperatures beyond the 98th percentile of the temperature distribution over the period from 1945-2012. We considered six heat wave definitions using maximum, minimum, and average air temperatures and apparent temperatures. Associations by heat wave characteristics were examined. Among all outcome-heat wave combinations, associations were strongest between ED visits for acute renal failure and heat waves defined by maximum apparent temperature at lag 0 [relative risk (RR) = 1.15; 95% confidence interval (CI): 1.03-1.29], ED visits for ischemic stroke and heat waves defined by minimum temperature at lag 0 (RR = 1.09; 95% CI: 1.02-1.17), and ED visits for intestinal infection and heat waves defined by average temperature at lag 1 (RR = 1.10; 95% CI: 1.00-1.21). ED visits for all internal causes were associated with heat waves defined by maximum temperature at lag 1 (RR = 1.02; 95% CI: 1.00, 1.04). Heat waves can confer additional risks of ED visits beyond those of daily air temperature, even in a region with high air-conditioning prevalence. https://doi.org/10.1289/EHP44.

Determining osmotic pressure of drug solutions by air humidity in equilibrium method.

PubMed

Zhan, Xiancheng; Li, Hui; Yu, Lan; Wei, Guocui; Li, Chengrong

2014-06-01

To establish a new osmotic pressure measuring method with a wide measuring range. The osmotic pressure of drug solutions is determined by measuring the relative air humidity in equilibrium with the solution. The freezing point osmometry is used as a control. The data obtained by the proposed method are comparable to those by the control method, and the measuring range of the proposed method is significantly wider than that of the control method. The proposed method is performed in an isothermal and equilibrium state, so it overcomes the defects of the freezing point and dew point osmometries which result from the heterothermal process in the measurement, and therefore is not limited to diluted solutions.

Large Dew water collectors in a village of S-Morocco (Idouasskssou)

NASA Astrophysics Data System (ADS)

Lekouch, I.; Clus, O.; Durand, M.; Lanfourmi, M.; Muselli, M.; Milimouk, I.; Beysens, D.

2010-07-01

With precipitations close to 227 mm/year in average, the coastal region of south Morocco presents a chronically shortage of drinkable and fresh water. Since 1994, in the Mirleft area (150 km south of Agadir), inhabitants are facing a critically drought event. In the year 2007, only 49 mm of rain was recorded. However, measurements in Mirleft in the same year, showed that the dew yield was on order of 40 % of rain fall. In order to show to the local population the interest of recovering dew water in addition to rain water, a small nearby village (Idouasskssou, 8 km SE of Mirleft) was equipped with three pilot condensers of 136 m2 total surface area. In order to ensure a good integration of the project by the village inhabitants, a local organization (Association IMRJANE) collaborated to the project. A concrete tank at ground level with a flat horizontal surface, easily accessible for inhabitants and also a model for traditional Morocco terrace roofings, has been equipped with two lines of condensers (40.6 m²). All roofing materials were from local shops. Only the special radiative and hydrophilic coating was coming from non local resources (see www.opur.fr). The top of a second tank (aside the first one) was renovated and covered with a 21.2 m² two slopes steel roof, insulated and painted with the special dew coating as above. These roofs represent a condensation surface comparable to that of a very little house. A third condenser, with 73.8 m² surface area, was implemented directly on the ground, ensuring minimal work and very cheap implementation costs. Dew was collected and measured in one of the concrete tanks. The water production during 6 months, from 15-12-2008 to 31-07-2009 (137 dew events, 47 % of days) was more than 3800 L (more than 0.2 mm/dew day). It is important to note that, while the devices are specifically designed to condense dew water, they also harvest rain and fog as well, thus providing to the population a valuable water resource.

Photosynthesis of the cyanobacterial soil-crust lichen Collema tenax from arid lands in southern Utah, USA: Role of water content on light and temperature responses of CO2 exchange

USGS Publications Warehouse

Lange, Otto L.; Belnap, Jayne; Reichenberger, H.

1998-01-01

1. The gelatinous cyanobacterial Collema tenax is a dominant lichen of biotic soil crusts in the western United States. In laboratory experiments, we studied CO2 exchange of this species as dependent on water content (WC), light and temperature. Results are compared with performance of green-algal lichens of the same site investigated earlier.2. As compared with published data, photosynthetic capacity of C. tenax is higher than that of other cyanobacterial and green-algal soil-crust species studied. At all temperatures and photon flux densities of ecological relevance, net photosynthesis (NP) shows a strong depression at high degrees of hydration; maximal apparent quantum-use efficiency of CO2 fixation is also reduced. Water requirements (moisture compensation point, WC for maximal NP) are higher than that of the green-algal lichens. Collema tenax exhibits extreme ‘sun plant’ features and is adapted to high thallus temperatures.3. Erratic rain showers are the main source of moisture for soil crusts on the Colorado Plateau, quickly saturating the lichens with liquid water. High water-holding capacity of C. tenax ensures extended phases of favourable hydration at conditions of high light and temperature after the rain for substantial photosynthetic production. Under such conditions the cyanobacterial lichen appears superior over its green-algal competitors, which seem better adapted to habitats with high air humidity, dew or fog as prevailing source of moisture.

Airborne measurements of total reactive odd nitrogen (NO(y))

NASA Technical Reports Server (NTRS)

Huebler, G.; Fahey, D. W.; Ridley, B. A.; Gregory, G. L.; Fehsenfeld, F. C.

1992-01-01

Airborne total reactive odd nitrogen measurements were made during August and September 1986 over the continental United States and off the west coast over the Pacific Ocean during NASA's Global Tropospheric Experiment/Chemical Instrumentation Test and Evaluation 2 program. Measurements were made in the marine and continental boundary layer and the free troposphere up to 6.1 km altitude. NO(y) mixing ratios between 24 pptv and more than 1 ppbv were found, with median values of 101 pptv in the marine boundary layer, 298 pptv in the marine free troposphere, and 288 pptv in the continental free troposphere, respectively. The marine troposphere exhibited layered structure which was also seen in the simultaneously measured ozone mixing ratio and dew point temperature. The averaged vertical NO(y) profile over the ocean does not show a distinct gradient. The NO(y) mixing ratio over the continent decreases with increasing altitude. The latter is consistent with our understanding that the continents are the major source region for these gases.

A Comparison of the Forecast Skills among Three Numerical Models

NASA Astrophysics Data System (ADS)

Lu, D.; Reddy, S. R.; White, L. J.

2003-12-01

Three numerical weather forecast models, MM5, COAMPS and WRF, operating with a joint effort of NOAA HU-NCAS and Jackson State University (JSU) during summer 2003 have been chosen to study their forecast skills against observations. The models forecast over the same region with the same initialization, boundary condition, forecast length and spatial resolution. AVN global dataset have been ingested as initial conditions. Grib resolution of 27 km is chosen to represent the current mesoscale model. The forecasts with the length of 36h are performed to output the result with 12h interval. The key parameters used to evaluate the forecast skill include 12h accumulated precipitation, sea level pressure, wind, surface temperature and dew point. Precipitation is evaluated statistically using conventional skill scores, Threat Score (TS) and Bias Score (BS), for different threshold values based on 12h rainfall observations whereas other statistical methods such as Mean Error (ME), Mean Absolute Error(MAE) and Root Mean Square Error (RMSE) are applied to other forecast parameters.

Photocatalytic disinfection of surfaces with copper doped Ti02 nanotube coatings illuminated by ceiling mounted fluorescent light

PubMed Central

Koklic, Tilen; Pintarič, Štefan; Zdovc, Irena; Golob, Majda; Umek, Polona; Mehle, Alma; Dobeic, Martin; Štrancar, Janez

2018-01-01

High economic burden is associated with foodborne illnesses. Different disinfection methods are therefore employed in food processing industry; such as use of ultraviolet light or usage of surfaces with copper-containing alloys. However, all the disinfection methods currently in use have some shortcomings. In this work we show that copper doped TiO2 nanotubes deposited on existing surfaces and illuminated with ceiling mounted fluorescent lights can retard the growth of Listeria Innocua by 80% in seven hours of exposure to the fluorescent lights at different places in a food processing plant or in the laboratory conditions with daily reinocuation and washing. The disinfection properties of the surfaces seem to depend mainly on the temperature difference of the surface and the dew point, where for the maximum effectiveness the difference should be about 3 degrees celsius. The TiO2 nanotubes have a potential to be employed for an economical and continuous disinfection of surfaces. PMID:29768464

The 1979 Southeastern Virginia Urban Plume Study (SEV-UPS): Surface and airborne studies

NASA Technical Reports Server (NTRS)

White, J. H.; Eaton, W. C.; Saeger, M. L.; Strong, R. B.; Tommerdahl, J. B.

1980-01-01

The operation of two surface monitoring stations (one in downtown Norfolk, Virginia, one south of the city near the Great Dismal Swamp) and the collection of 40 hours of airborne measurements is described. Surface site measurements of ozone, oxides of nitrogen, sulfur dioxide, temperature, dew point, b sub seat, and condensation nuclei were made. Instrument calibrations, quality assurance audits, and preliminary data analysis in support of the Urban Plume Study were also made. The air pollution problems that were addressed are discussed. Data handling procedures followed for the surface stations are presented. The operation of the aircraft sampling platform is described. Aircraft sampling procedures are discussed. A preliminary descriptive analysis of the aircraft data is given along with data or plots for surface sites, airborne studies, hydrocarbon species, and instrument performance audits. Several of the aircraft flights clearly show the presence of an urban ozone plume downwind of Norfolk in the direction of the mean wind flow.

Heat pump with freeze-up prevention

DOEpatents

Ecker, Amir L.

1981-01-01

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid prevents freeze up of the second heat exchanger by keeping the temperature above the dew point; and, optionally, provides heat for efficient operation.

Photocatalytic disinfection of surfaces with copper doped Ti02 nanotube coatings illuminated by ceiling mounted fluorescent light.

PubMed

Koklic, Tilen; Pintarič, Štefan; Zdovc, Irena; Golob, Majda; Umek, Polona; Mehle, Alma; Dobeic, Martin; Štrancar, Janez

2018-01-01

High economic burden is associated with foodborne illnesses. Different disinfection methods are therefore employed in food processing industry; such as use of ultraviolet light or usage of surfaces with copper-containing alloys. However, all the disinfection methods currently in use have some shortcomings. In this work we show that copper doped TiO2 nanotubes deposited on existing surfaces and illuminated with ceiling mounted fluorescent lights can retard the growth of Listeria Innocua by 80% in seven hours of exposure to the fluorescent lights at different places in a food processing plant or in the laboratory conditions with daily reinocuation and washing. The disinfection properties of the surfaces seem to depend mainly on the temperature difference of the surface and the dew point, where for the maximum effectiveness the difference should be about 3 degrees celsius. The TiO2 nanotubes have a potential to be employed for an economical and continuous disinfection of surfaces.

Experimental research of heterogeneous nuclei in superheated steam

NASA Astrophysics Data System (ADS)

Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

2016-03-01

A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

Fungal spore concentrations in indoor and outdoor air in university libraries, and their variations in response to changes in meteorological variables.

PubMed

Flores, María Elena Báez; Medina, Pável Gaxiola; Camacho, Sylvia Páz Díaz; de Jesús Uribe Beltrán, Magdalena; De la Cruz Otero, María del Carmen; Ramírez, Ignacio Osuna; Hernández, Martín Ernesto Tiznado

2014-08-01

The fungal spore concentration (FSC) in the air poses a risk for human health. This work studied the FSC in university libraries and how it is affected by environmental factors. A total of 347 samples were obtained using a Microbio MB2(®) Aerosol Sampler. The wind speed (WS), cross wind (CW), temperature (T), relative humidity (HR), barometric pressure (BP) and dew point (DP) were recorded using a Kestrel(®) 4500 weather station. The median indoor/outdoor FSC was 360/1230 CFU m(-3). FSC correlated inversely with BP, HR and DP; and positively with WS and CW; whereas T showed negative or positive correlation with FSC, depending on the region or sampling time. Eleven fungal genera were found and the dominant isolates were identified as Aspergillus niger, Aspergillus tamarii and Aspergillus oryzae. All fungi identified are known to be allergenic. It was concluded that environmental variables can influence the air FSC in different ways.

Experimental Studies of the Formation/Deposition of Sodium Sulfate in/from Combustion Gases. [hot corrosion in gas turbine engines

NASA Technical Reports Server (NTRS)

Rosner, D. E.

1978-01-01

Processes related to the hot corrosion of gas turbine components were examined in two separate investigations. Monochromatic laser light was used to probe condensation onset and condensate film growth (via interference of reflected light) on electrically heated ribbons immersed in seeded, flat flame combustion product gases. Boron trichloride is used as the seed gas in these preliminary experiments conducted to obtain precise measurements of the dew point/deposition rates. Because of the importance of gaseous Na(g) as a precursor to NaSO4 formation, the kinetics and mechanisms of the heterogeneous reaction H(g) + NaCl(s) yields Na(g) + HCl(g) was studied using atomic absorption spectroscopy combined with microwave discharge-vacuum flow reactor techniques at moderate temperatures. Preliminary results indicate the H-atom attack of solid NaCl vaporization is negligible; hence the corresponding gas phase (homogeneous) reaction no role in the observed Na(g) production.

A critical analysis of one standard and five methods to monitor surface wetness and time-of-wetness

NASA Astrophysics Data System (ADS)

Camuffo, Dario; della Valle, Antonio; Becherini, Francesca

2018-05-01

Surface wetness is a synergistic factor to determine atmospheric corrosion, monument weathering, mould growth, sick buildings, etc. However, its detection and monitoring are neither easy nor homogeneous, for a number of factors that may affect readings. Various types of methods and sensors, either commercial or prototypes built in the lab, have been investigated and compared, i.e. the international standard ISO 9223 to evaluate corrosivity after wetness and time-of-wetness; indirect evaluation of wetness, based on the dew point calculated after the output of temperature and relative humidity sensors and direct measurements by means of capacitive wetness sensors, safety sensors, rain sensors (also known as leaf wetness sensors), infrared reflection sensors and fibre optic sensors. A comparison between the different methods is presented, specifying physical principles, forms of wetting to which they are respondent (i.e. condensation, ice melting, splashing drops, percolation and capillary rise), critical factors, use and cost.

[The influence of alcohol consumption on the chronological patterns of sudden cardiac death].

PubMed

Sapozhnikov, S P; Kozlov, V A; Golenkov, A V; Kichigin, V A; Karyshev, P B; Samarkina, O Yu

2015-01-01

The objective of the present study was the retrospective analysis of the materials collected by the Republican Bureau of Forensic Medical Expertise, Ministry of Health and Social Development of Chuvash Republic, during the period from 1997 till 2002 for the elucidation of the chronological patterns of sudden cardiac death (SCD) associated with alcohol consumption depending on the sex and age of the victims, days of the week and months of the year as well as weather conditions. It was shown that the peak of mortality among men and women taking no alcohol fell on Monday. It was highest in May and decreased by February. The alcohol consumption significantly changes the chronological patterns of mortality from cardiovascular pathology. It was highest among the women abusing alcohol in August and October. The study has demonstrated a weak negative correlation between the frequency of sudden cardiac death among non-consumers of alcohol and dew-point temperature among the persons having alcohol in blood.

Analysis and use of VAS satellite data

NASA Technical Reports Server (NTRS)

Fuelberg, Henry E.; Andrews, Mark J.; Beven, John L., II; Moore, Steven R.; Muller, Bradley M.

1989-01-01

Four interrelated investigations have examined the analysis and use of VAS satellite data. A case study of VAS-derived mesoscale stability parameters suggested that they would have been a useful supplement to conventional data in the forecasting of thunderstorms on the day of interest. A second investigation examined the roles of first guess and VAS radiometric data in producing sounding retrievals. Broad-scale patterns of the first guess, radiances, and retrievals frequently were similar, whereas small-scale retrieval features, especially in the dew points, were often of uncertain origin. Two research tasks considered 6.7 micron middle tropospheric water vapor imagery. The first utilized radiosonde data to examine causes for two areas of warm brightness temperature. Subsidence associated with a translating jet streak was important. The second task involving water vapor imagery investigated simulated imagery created from LAMPS output and a radiative transfer algorithm. Simulated image patterns were found to compare favorably with those actually observed by VAS. Furthermore, the mass/momentum fields from LAMPS were powerful tools for understanding causes for the image configurations.

Thermoregulatory modeling use and application in the military workforce.

PubMed

Yokota, Miyo; Berglund, Larry G; Xu, Xiaojiang

2014-05-01

Thermoregulatory models have been used in the military to quantify probabilities of individuals' thermal-related illness/injury. The uses of the models have diversified over the past decade. This paper revisits an overall view of selected thermoregulatory models used in the U.S. military and provides examples of actual practical military applications: 1) the latest military vehicle designed with armor and blast/bulletproof windows was assessed to predict crews' thermal strains levels inside vehicles under hot environment (air temperature [Ta]: 29-43 °C, dew point: 13 °C); 2) a military working dog (MWD) model was developed by modifying existing human thermoregulatory models with canine physical appearance and physiological mechanisms; 3) thermal tolerance range of individuals from a large military group (n = 100) exposed to 35 °C/40% relative humidity were examined using thermoregulatory modeling and multivariate statistical analyses. Model simulation results assist in the decisions for the strategic planning and preventions of heat stress. Published by Elsevier Ltd.

Mach-Number Measurement with Laser and Pressure Probes in Humid Supersonic Flow

NASA Technical Reports Server (NTRS)

Herring, G. C.

2008-01-01

Mach-number measurements using a nonintrusive optical technique, laser-induced thermal acoustics (LITA), are compared to pressure probes in humid supersonic airflow. The two techniques agree well in dry flow (-35 C dew point), but LITA measurements show about five times larger fractional change in Mach number than that of the pressure-probe when water is purposefully introduced into the flow. Possible reasons for this discrepancy are discussed.

Satellite Estimation of Daily Land Surface Water Vapor Pressure Deficit from AMSR- E

NASA Astrophysics Data System (ADS)

Jones, L. A.; Kimball, J. S.; McDonald, K. C.; Chan, S. K.; Njoku, E. G.; Oechel, W. C.

2007-12-01

Vapor pressure deficit (VPD) is a key variable for monitoring land surface water and energy exchanges, and estimating plant water stress. Multi-frequency day/night brightness temperatures from the Advanced Microwave Scanning Radiometer on EOS Aqua (AMSR-E) were used to estimate daily minimum and average near surface (2 m) air temperatures across a North American boreal-Arctic transect. A simple method for determining daily mean VPD (Pa) from AMSR-E air temperature retrievals was developed and validated against observations across a regional network of eight study sites ranging from boreal grassland and forest to arctic tundra. The method assumes that the dew point and minimum daily air temperatures tend to equilibrate in areas with low night time temperatures and relatively moist conditions. This assumption was tested by comparing the VPD algorithm results derived from site daily temperature observations against results derived from AMSR-E retrieved temperatures alone. An error analysis was conducted to determine the amount of error introduced in VPD estimates given known levels of error in satellite retrieved temperatures. Results indicate that the assumption generally holds for the high latitude study sites except for arid locations in mid-summer. VPD estimates using the method with AMSR-E retrieved temperatures compare favorably with site observations. The method can be applied to land surface temperature retrievals from any sensor with day and night surface or near-surface thermal measurements and shows potential for inferring near-surface wetness conditions where dense vegetation may hinder surface soil moisture retrievals from low-frequency microwave sensors. This work was carried out at The University of Montana, at San Diego State University, and at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

Using a Statistical Approach to Anticipate Leaf Wetness Duration Under Climate Change in France

NASA Astrophysics Data System (ADS)

Huard, F.; Imig, A. F.; Perrin, P.

2014-12-01

Leaf wetness plays a major role in the development of fungal plant diseases. Leaf wetness duration (LWD) above a threshold value is determinant for infection and can be seen as a good indicator of impact of climate on infection occurrence and risk. As LWD is not widely measured, several methods, based on physics and empirical approach, have been developed to estimate it from weather data. Many LWD statistical models do exist, but the lack of standard for measurements require reassessments. A new empirical LWD model, called MEDHI (Modèle d'Estimation de la Durée d'Humectation à l'Inra) was developed for french configuration for wetness sensors (angle : 90°, height : 50 cm). This deployment is different from what is usually recommended from constructors or authors in other countries (angle from 10 to 60°, height from 10 to 150 cm…). MEDHI is a decision support system based on hourly climatic conditions at time steps n and n-1 taking account relative humidity, rainfall and previously simulated LWD. Air temperature, relative humidity, wind speed, rain and LWD data from several sensors with 2 configurations were measured during 6 months in Toulouse and Avignon (South West and South East of France) to calibrate MEDHI. A comparison of empirical models : NHRH (RH threshold), DPD (dew point depression), CART (classification and regression tree analysis dependant on RH, wind speed and dew point depression) and MEDHI, using meteorological and LWD measurements obtained during 5 months in Toulouse, showed that the development of this new model MEHDI was definitely better adapted to French conditions. In the context of climate change, MEDHI was used for mapping the evolution of leaf wetness duration in France from 1950 to 2100 with the French regional climate model ALADIN under different Representative Concentration Pathways (RCPs) and using a QM (Quantile-Mapping) statistical downscaling method. Results give information on the spatial distribution of infection risks during the current century. Such approach could be easily combined with thermal response curves of fungal infection for various pathogens.

Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinman L. I.; Daum, P. H.; Lee, Y.-N.

2012-01-04

During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate. Pollutant layers in the free troposphere (FT) can be a result of emissionsmore » to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a boundary layer (BL) contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (D{sub p} > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25 % of aerosol with D{sub p} > 100 nm are interstitial (not activated). A direct comparison of pre-cloud and in-cloud aerosol yields a higher estimate. Artifacts in the measurement of interstitial aerosol due to droplet shatter and evaporation are discussed. Within each of 102 constant altitude cloud transects, CDNC and interstitial aerosol were anti-correlated. An examination of one cloud as a case study shows that the interstitial aerosol appears to have a background, upon which is superimposed a high frequency signal that contains the anti-correlation. The anti-correlation is a possible source of information on particle activation or evaporation.« less

Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinman, L.I.; Daum, P. H.; Lee, Y.-N.

2011-06-21

During the VOCALS Regional Experiment, the DOE G-1 aircraft was used to sample a varying aerosol environment pertinent to properties of stratocumulus clouds over a longitude band extending 800 km west from the Chilean coast at Arica. Trace gas and aerosol measurements are presented as a function of longitude, altitude, and dew point in this study. Spatial distributions are consistent with an upper atmospheric source for O{sub 3} and South American coastal sources for marine boundary layer (MBL) CO and aerosol, most of which is acidic sulfate in agreement with the dominant pollution source being SO{sub 2} from Cu smeltersmore » and power plants. Pollutant layers in the free troposphere (FT) can be a result of emissions to the north in Peru or long range transport from the west. At a given altitude in the FT (up to 3 km), dew point varies by 40 C with dry air descending from the upper atmospheric and moist air having a BL contribution. Ascent of BL air to a cold high altitude results in the condensation and precipitation removal of all but a few percent of BL water along with aerosol that served as CCN. Thus, aerosol volume decreases with dew point in the FT. Aerosol size spectra have a bimodal structure in the MBL and an intermediate diameter unimodal distribution in the FT. Comparing cloud droplet number concentration (CDNC) and pre-cloud aerosol (Dp > 100 nm) gives a linear relation up to a number concentration of {approx}150 cm{sup -3}, followed by a less than proportional increase in CDNC at higher aerosol number concentration. A number balance between below cloud aerosol and cloud droplets indicates that {approx}25% of aerosol in the PCASP size range are interstitial (not activated). One hundred and two constant altitude cloud transects were identified and used to determine properties of interstitial aerosol. One transect is examined in detail as a case study. Approximately 25 to 50% of aerosol with D{sub p} > 110 nm were not activated, the difference between the two approaches possibly representing shattered cloud droplets or unknown artifact. CDNC and interstitial aerosol were anti-correlated in all cloud transects, consistent with the occurrence of dry in-cloud areas due to entrainment or circulation mixing.« less

Evaluation of near-surface temperature, humidity, and equivalent temperature from regional climate models applied in type II downscaling

NASA Astrophysics Data System (ADS)

Pryor, S. C.; Schoof, J. T.

2016-04-01

Atmosphere-surface interactions are important components of local and regional climates due to their key roles in dictating the surface energy balance and partitioning of energy transfer between sensible and latent heat. The degree to which regional climate models (RCMs) represent these processes with veracity is incompletely characterized, as is their ability to capture the drivers of, and magnitude of, equivalent temperature (Te). This leads to uncertainty in the simulation of near-surface temperature and humidity regimes and the extreme heat events of relevance to human health, in both the contemporary and possible future climate states. Reanalysis-nested RCM simulations are evaluated to determine the degree to which they represent the probability distributions of temperature (T), dew point temperature (Td), specific humidity (q) and Te over the central U.S., the conditional probabilities of Td|T, and the coupling of T, q, and Te to soil moisture and meridional moisture advection within the boundary layer (adv(Te)). Output from all RCMs exhibits discrepancies relative to observationally derived time series of near-surface T, q, Td, and Te, and use of a single layer for soil moisture by one of the RCMs does not appear to substantially degrade the simulations of near-surface T and q relative to RCMs that employ a four-layer soil model. Output from MM5I exhibits highest fidelity for the majority of skill metrics applied herein, and importantly most realistically simulates both the coupling of T and Td, and the expected relationships of boundary layer adv(Te) and soil moisture with near-surface T and q.

Digital Earth Watch: Investigating the World with Digital Cameras

NASA Astrophysics Data System (ADS)

Gould, A. D.; Schloss, A. L.; Beaudry, J.; Pickle, J.

2015-12-01

Every digital camera including the smart phone camera can be a scientific tool. Pictures contain millions of color intensity measurements organized spatially allowing us to measure properties of objects in the images. This presentation will demonstrate how digital pictures can be used for a variety of studies with a special emphasis on using repeat digital photographs to study change-over-time in outdoor settings with a Picture Post. Demonstrations will include using inexpensive color filters to take pictures that enhance features in images such as unhealthy leaves on plants, or clouds in the sky. Software available at no cost from the Digital Earth Watch (DEW) website that lets students explore light, color and pixels, manipulate color in images and make measurements, will be demonstrated. DEW and Picture Post were developed with support from NASA. Please visit our websites: DEW: http://dew.globalsystemsscience.orgPicture Post: http://picturepost.unh.edu

Evidence for direct water absorption by shallow-rooted desert plants in desert-oasis ecotone, Northwest China

NASA Astrophysics Data System (ADS)

Fang, Jing

2014-05-01

Besides the absorption by roots from the soil substrate, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. For many tropical epiphytic orchids, air moisture can be absorbed directly by aerial roots. Some conifers are also found to utilize air moisture by foliar absorption during the summer fog season. However, few studies have been carried out on the atmospheric water vapor absorption by shallow-rooted desert plants. We conducted experiments in desert-oasis ecotone and investigated the effects of dew absorbed by three kinds of shallow-rooted seedlings on net photosynthesis rate, as well as on other water relations variables. Three kinds of typical shallow-rooted desert species (Bassia dasyphylla, Salsola collina and Corispermum declinatum) have been chosen and potted. Each species were subjected to contrasting watering regimes (normal and deficient) and different air moisture conditions (having dew and having no dew) for 10 weeks. Net photosynthesis rate was measured on six occasions during the study. Other water relations variables (midday shoot water potential, relative water content, stomatal conductance) were also measured. Under the dew conditions, average net photosynthesis rate, shoot water potential, leaf relative water content and stomatal conductance increased, with greater responses observed for plants subjected to a deficient watering regime than for well-watered plants. These results indicated dew occurred in arid region could be utilized through foliar absorption by some shallow-rooted plants, and for the shallow-rooted plants, the presence of dew could significantly relieve the deficit of water in water-stressed regime.

Climatological Study of the Short-Term Variation of the 0 C, -10 C, AND -20 C Altitude Levels Over the Florida Spaceport

NASA Technical Reports Server (NTRS)

Huddleston, Lisa; Maier, Launa; Smith, Kristin; Roeder, William P.; McAleenan, Mike; Winters, Katherine A.; Godoy, Laura M.; Hinkley, Jeremy

2017-01-01

For evaluation of the potential of cloud electrification, it is necessary to know the altitude of the 0, -10 and -20 degree Celsius levels. Cape Canaveral Air Force Station has recorded balloon launch data back to 1989. In support of rocket launches, often multiple balloons are launched within minutes of each other in the 4-6 hours leading up to launch. In the past, temperature data from sondes was typically available every hour or so through the launch countdown, allowing for frequent updates of these critical temperature thresholds. Recently, launch customers are relying on jimsphere and wind profiler data that do not have a thermodynamic component in the latter 4-6 hours of a countdown. This study compares the altitude differences of the 0, -10 and -20 degree Celsius levels from GPS-tracked consecutive balloon pairs not to exceed 6 hours apart. The analysis uses 3,198 soundings from 2001 to 2013. Approximately 20, 17, and 13 percent of the time the altitude of the temperature level in question (0, -10, -20 degrees C respectively), varies by more than 500 feet (operationally significant threshold) within 6 hours. This study analyzes the altitude variability as a function of several meteorological parameters, such as dew point depression and solar zenith angle. Additionally, the study concludes with impacts to launch operations.

Weather forecasting based on hybrid neural model

NASA Astrophysics Data System (ADS)

Saba, Tanzila; Rehman, Amjad; AlGhamdi, Jarallah S.

2017-11-01

Making deductions and expectations about climate has been a challenge all through mankind's history. Challenges with exact meteorological directions assist to foresee and handle problems well in time. Different strategies have been investigated using various machine learning techniques in reported forecasting systems. Current research investigates climate as a major challenge for machine information mining and deduction. Accordingly, this paper presents a hybrid neural model (MLP and RBF) to enhance the accuracy of weather forecasting. Proposed hybrid model ensure precise forecasting due to the specialty of climate anticipating frameworks. The study concentrates on the data representing Saudi Arabia weather forecasting. The main input features employed to train individual and hybrid neural networks that include average dew point, minimum temperature, maximum temperature, mean temperature, average relative moistness, precipitation, normal wind speed, high wind speed and average cloudiness. The output layer composed of two neurons to represent rainy and dry weathers. Moreover, trial and error approach is adopted to select an appropriate number of inputs to the hybrid neural network. Correlation coefficient, RMSE and scatter index are the standard yard sticks adopted for forecast accuracy measurement. On individual standing MLP forecasting results are better than RBF, however, the proposed simplified hybrid neural model comes out with better forecasting accuracy as compared to both individual networks. Additionally, results are better than reported in the state of art, using a simple neural structure that reduces training time and complexity.

Temperature Regulation in Crewmembers After a 115-Day Space Flight

NASA Technical Reports Server (NTRS)

Lee, S. M. C.; Williams, W. J.; Siconolfi, S. F.; Gonzalez, R.; Greenleaf, J. E.; Mikhavlov, V.; Kobzev, Y.; Fortney, S. M.

1996-01-01

Impaired thermoregulation, which has been observed during exercise following bed rest, may significantly impact crewmembers during space flight operations by decreasing exercise capacity and orthostatic tolerance. Impaired temperature regulation would cause higher levels of core temperature, due to an attenuated cutaneous vasodilatory reflex and sweating response, for a given oxygen consumption. Two mate crewmembers of the Mir 18 mission performed supine cycle exercise se (20 min @ 40% and 20 min @ 65% preflight VO2pk) 145 days preflight and 5 days postflight. Core temperature (Tcore) was measured by an ingestible telemetry pill, skin blood flow (SBF) by laser Doppler velocimetry, and sweat rate (SR) by dew point hygrometry. Tcore at the time of test termination was similar (37.8 C) for both subjects before and after flight despite a shorter test duration (40 vs 28-29 minutes) postflight. The slopes of the SBF/Tcore relationship (Subj 1: 396 vs 214; Subj 2: 704 vs 143 Perfusion Unit/degC) and SR/Tcore relationship (Subj 1: 4.5 vs 2.1; Subj 2: 11.0 vs 3.6mg/min/sq cm/degC) were reduced postflight. Tcore thresholds for both SR (Subj 1: 37.4 vs 37.6; Subj 2: 37.6 vs 37.6 C) and SBF (Subj 1: 37.3 vs 37.5; Subj 2: 37.6 vs 37.7 C) were similar pre- to postflight. For these 2 crewmembers, it appeared that thermoregulation during exercise was impaired as evidenced by compromised heat loss responses after long-duration space flight.

7 CFR 51.3741 - U.S. Commercial.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Standards for Grades of Honey Dew and Honey Ball Type Melons Grades § 51.3741 U.S. Commercial. “U.S. Commercial” consists of honey dew or honey ball type melons which meet the requirements of U.S. No. 1 grade...

7 CFR 51.3741 - U.S. Commercial.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Standards for Grades of Honey Dew and Honey Ball Type Melons Grades § 51.3741 U.S. Commercial. “U.S. Commercial” consists of honey dew or honey ball type melons which meet the requirements of U.S. No. 1 grade...

Hierarchical structures of cactus spines that aid in the directional movement of dew droplets.

PubMed

Malik, F T; Clement, R M; Gethin, D T; Kiernan, M; Goral, T; Griffiths, P; Beynon, D; Parker, A R

2016-08-06

Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. Spines emanating from one of the areoles of C. cinerea were submerged in water laced with fluorescent nanoparticles and this particular areole with its spines and a small area of stem was removed and imaged. These images clearly showed that fluorescent water had moved into the stem of the plant. Lines of vascular bundles radiating inwards from the surface areoles (from where the spines emanate) to the core of the stem were detected using magnetic resonance imaging, with the exception of F. wislizenii that does not harvest dew on its spines. Spine microstructures were examined using SEM images and surface roughness measurements (Ra and Rz) taken of the spines of C. cinerea It was found that a roughness gradient created by tapered microgrooves existed that could potentially direct surface water from a spine tip to its base.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

Hierarchical structures of cactus spines that aid in the directional movement of dew droplets

PubMed Central

Clement, R. M.; Gethin, D. T.; Kiernan, M.; Goral, T.; Griffiths, P.; Beynon, D.; Parker, A. R.

2016-01-01

Three species of cactus whose spines act as dew harvesters were chosen for this study: Copiapoa cinerea var. haseltoniana, Mammillaria columbiana subsp. yucatanensis and Parodia mammulosa and compared with Ferocactus wislizenii whose spines do not perform as dew harvesters. Time-lapse snapshots of C. cinerea showed movement of dew droplets from spine tips to their base, even against gravity. Spines emanating from one of the areoles of C. cinerea were submerged in water laced with fluorescent nanoparticles and this particular areole with its spines and a small area of stem was removed and imaged. These images clearly showed that fluorescent water had moved into the stem of the plant. Lines of vascular bundles radiating inwards from the surface areoles (from where the spines emanate) to the core of the stem were detected using magnetic resonance imaging, with the exception of F. wislizenii that does not harvest dew on its spines. Spine microstructures were examined using SEM images and surface roughness measurements (Ra and Rz) taken of the spines of C. cinerea. It was found that a roughness gradient created by tapered microgrooves existed that could potentially direct surface water from a spine tip to its base. This article is part of the themed issue ‘Bioinspired hierarchically structured surfaces for green science’. PMID:27354735

Creating a Regional Drought Early Warning System (DEWS) for California and Nevada: Building Off of Information Gathered and Lessons Learned after 5 Years of Drought

NASA Astrophysics Data System (ADS)

Sheffield, A. M.; Marrs, A.; Wall, T. U.; Cayan, D.; Kalansky, J.; Redmond, K. T.; Huntington, J. L.; McEvoy, D.

2016-12-01

In California and Nevada, a diverse set of sectors and regional variation amidst a 5-year spell of drought presents multiple needs, gaps and challenges in providing usable available information for drought preparedness. In response to the findings of Governor Sandoval's Nevada Drought Forum and a series of stakeholder meetings and drought and climate outlooks in California, NOAA's National Integrated Drought Information System (NIDIS) has created the California-Nevada DEWS to leverage the activities of the existing California DEWS to better reflect the needs of the region after five years of unprecedented drought. In addition to presenting timely drought status and outlooks, these stakeholder-oriented meetings and listening sessions explored local drought impacts and drought informational needs. The information gathered will be integrated into a strategic plan for California-Nevada DEWS. This strategic plan will provide a roadmap of planned research and activities to enhance the ability of stakeholders in the region to better plan, prepare for and mitigate the impacts of drought. The implementation will involve key partners from a diverse network of federal, regional, tribal, state and local agencies and interests and will result in regionally specific deliverables to advance the California-Nevada DEWS.

Perceived temperature in the course of climate change: an analysis of global heat index from 1979 to 2013

NASA Astrophysics Data System (ADS)

Lee, D.; Brenner, T.

2015-08-01

The increase in global mean temperatures resulting from climate change has wide reaching consequences for the earth's ecosystems and other natural systems. Many studies have been devoted to evaluating the distribution and effects of these changes. We go a step further and propose the use of the heat index, a measure of the temperature as perceived by humans, to evaluate global changes. The heat index, which is computed from temperature and relative humidity, is more important than temperature for the health of humans and animals. Even in cases where the heat index does not reach dangerous levels from a health perspective, it has been shown to be an important factor in worker productivity and thus in economic productivity. We compute the heat index from dew point temperature and absolute temperature 2 m above ground from the ERA-Interim reanalysis data set for the years 1979-2013. The described data set provides global heat index aggregated to daily minima, means and maxima per day (doi:10.1594/PANGAEA.841057). This paper examines these data, as well as showing aggregations to monthly and yearly values. Furthermore, the data are spatially aggregated to the level of countries after being weighted by population density in order to facilitate the analysis of its impact on human health and productivity. The resulting data deliver insights into the spatiotemporal development of near-ground heat index during the course of the past three decades. It is shown that the impact of changing heat index is unevenly distributed through space and time, affecting some areas differently than others. The data can serve as a basis for evaluating and understanding the evolution of heat index in the course of climate change, as well as its impact on human health and productivity.

Superheater Corrosion In Biomass Boilers: Today's Science and Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharp, William

2011-12-01

This report broadens a previous review of published literature on corrosion of recovery boiler superheater tube materials to consider the performance of candidate materials at temperatures near the deposit melting temperature in advanced boilers firing coal, wood-based fuels, and waste materials as well as in gas turbine environments. Discussions of corrosion mechanisms focus on the reactions in fly ash deposits and combustion gases that can give corrosive materials access to the surface of a superheater tube. Setting the steam temperature of a biomass boiler is a compromise between wasting fuel energy, risking pluggage that will shut the unit down, andmore » creating conditions that will cause rapid corrosion on the superheater tubes and replacement expenses. The most important corrosive species in biomass superheater corrosion are chlorine compounds and the most corrosion resistant alloys are typically FeCrNi alloys containing 20-28% Cr. Although most of these materials contain many other additional additions, there is no coherent theory of the alloying required to resist the combination of high temperature salt deposits and flue gases that are found in biomass boiler superheaters that may cause degradation of superheater tubes. After depletion of chromium by chromate formation or chromic acid volatilization exceeds a critical amount, the protective scale gives way to a thick layer of Fe{sub 2}O{sub 3} over an unprotective (FeCrNi){sub 3}O{sub 4} spinel. This oxide is not protective and can be penetrated by chlorine species that cause further acceleration of the corrosion rate by a mechanism called active oxidation. Active oxidation, cited as the cause of most biomass superheater corrosion under chloride ash deposits, does not occur in the absence of these alkali salts when the chloride is present as HCl gas. Although a deposit is more corrosive at temperatures where it is molten than at temperatures where it is frozen, increasing superheater tube temperatures through the measured first melting point of fly ash deposits does not necessarily produce a step increase in corrosion rate. Corrosion rate typically accelerates at temperatures below the first melting temperature and mixed deposits may have a broad melting temperature range. Although the environment at a superheater tube surface is initially that of the ash deposits, this chemistry typically changes as the deposits mature. The corrosion rate is controlled by the environment and temperature at the tube surface, which can only be measured indirectly. Some results are counter-intuitive. Two boiler manufacturers and a consortium have developed models to predict fouling and corrosion in biomass boilers in order to specify tube materials for particular operating conditions. It would be very useful to compare the predictions of these models regarding corrosion rates and recommended alloys in the boiler environments where field tests will be performed in the current program. Manufacturers of biomass boilers have concluded that it is more cost-effective to restrict steam temperatures, to co-fire biofuels with high sulfur fuels and/or to use fuel additives rather than try to increase fuel efficiency by operating with superheater tube temperatures above melting temperature of fly ash deposits. Similar strategies have been developed for coal fired and waste-fired boilers. Additives are primarily used to replace alkali metal chloride deposits with higher melting temperature and less corrosive alkali metal sulfate or alkali aluminum silicate deposits. Design modifications that have been shown to control superheater corrosion include adding a radiant pass (empty chamber) between the furnace and the superheater, installing cool tubes immediately upstream of the superheater to trap high chloride deposits, designing superheater banks for quick replacement, using an external superheater that burns a less corrosive biomass fuel, moving circulating fluidized bed (CFB) superheaters from the convective pass into the hot recirculated fluidizing medium and adding an insulating layer to superheater tubes to raise their surface temperature above the dew point temperature of alkali chlorides. These design changes offer advantages but introduce other challenges. For example, operating with superheater temperatures above the dew point of alkali chlorides could require the use of creep-resistant tube alloys and doesn't eliminate chloride corrosion. Improved test methods that can be applied within this project include automated dimensional metrology to make a statistical analysis of depth of penetration and corrosion product thickness, and simultaneous thermal analysis measurements to quantify the melting of complex ashes and avoid the unreliability of the standard ash fusion test. Other important developments in testing include the installation of individually-temperature-controlled superheater loops for corrosion testing in operating boilers and temperature gradient testing.« less

Solubility modeling of refrigerant/lubricant mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michels, H.H.; Sienel, T.H.

1996-12-31

A general model for predicting the solubility properties of refrigerant/lubricant mixtures has been developed based on applicable theory for the excess Gibbs energy of non-ideal solutions. In our approach, flexible thermodynamic forms are chosen to describe the properties of both the gas and liquid phases of refrigerant/lubricant mixtures. After an extensive study of models for describing non-ideal liquid effects, the Wohl-suffix equations, which have been extensively utilized in the analysis of hydrocarbon mixtures, have been developed into a general form applicable to mixtures where one component is a POE lubricant. In the present study we have analyzed several POEs wheremore » structural and thermophysical property data were available. Data were also collected from several sources on the solubility of refrigerant/lubricant binary pairs. We have developed a computer code (NISC), based on the Wohl model, that predicts dew point or bubble point conditions over a wide range of composition and temperature. Our present analysis covers mixtures containing up to three refrigerant molecules and one lubricant. The present code can be used to analyze the properties of R-410a and R-407c in mixtures with a POE lubricant. Comparisons with other models, such as the Wilson or modified Wilson equations, indicate that the Wohl-suffix equations yield more reliable predictions for HFC/POE mixtures.« less

Effect of magnetic field on the flux pinning mechanisms in Al and SiC co-doped MgB2 superconductor

NASA Astrophysics Data System (ADS)

Kia, N. S.; Ghorbani, S. R.; Arabi, H.; Hossain, M. S. A.

2018-07-01

MgB2 superconductor samples co-doped with 0.02 wt. Al2O3 and 0-0.05 wt. SiC were studied by magnetization - magnetic field (M-H) loop measurements at different temperatures. The critical current density has been calculated by the Bean model, and the irreversibility field, Hirr, has been obtained by the Kramer method. The pinning mechanism of the co-doped sample with 2% Al and 5% SiC was investigated in particular due to its having the highest Hirr. The normalized volume pinning force f = F/Fmax as a function of reduced magnetic field h = H/Hirr has been obtained, and the pinning mechanism was studied by the Dew-Houghes model. It was found that the normal point pinning (NPP), the normal surface pinning (NSP), and the normal volume pinning (NVP) mechanisms play the main roles. The magnetic field and temperature dependence of contributions of the NPP, NSP, and NVP pinning mechanisms were obtained. The results show that the contributions of the pinning mechanisms depend on the temperature and magnetic field. From the temperature dependence of the critical current density within the collective pinning theory, it was found that both the δl pinning due to spatial fluctuations of the charge-carrier mean free path and the δTc pinning due to randomly distributed spatial variations in the transition temperature coexist at zero magnetic field in co-doped samples. Yet, the charge-carrier mean-free-path fluctuation pinning (δl) is the only important pinning mechanism at non-zero magnetic fields.