SHORT COMMUNICATION: Recognition of supercooled dew in a quartz crystal microbalance dew-point sensor by slip phenomena

Science.gov (United States)

Kwon, Su-Yong; Kim, Jong-Chul; Choi, Byung-Il

2007-10-01

Distinguishing between a supercooled dew and frost below 0 °C in dew/frost-point measurements is an important and challenging problem that has not yet been completely solved. This study presents a new method for the recognition of a supercooled dew in a dew/frost-point sensor. A quartz crystal microbalance (QCM) sensor was used as a dew/frost-point sensor to detect a dew and a supercooled dew as well as frost. The slip phenomenon occurring at an interface between the water droplet and the surface of the quartz crystal resonator of the QCM sensor gives a simple and accurate way of distinguishing between a supercooled dew and frost below 0 °C. This method can give a highly accurate measurement of the dew or the frost point without misreading in the dew-point sensor at temperatures below 0 °C.

Dew Frequency across the NEON Network from Infrared Radiometry

Science.gov (United States)

Ritter, F.; Berkelhammer, M. B.; Beysens, D.

2017-12-01

The surface energy budget is more difficult to close at night because of the absence of strong atmospheric turbulence, central in the eddy-covariance calculations. One approach to assessing the direction of the nocturnal latent heat flux is through studying the frequency and magnitude of dew formation in different ecosystems. However, most former dew studies on dew dynamics utilized artificial surfaces to collect dew, and did not have access to the surface temperature of natural surfaces in an ecosystem to provide a continuous whole-plot approach to constrain dew formation. Hourly in-situ measurements recently made available by the National Ecological Observatory Network (NEON) of the radiometric surface temperature and the meteorological variables provide a unique opportunity to make continuous estimates of dew formation across 19 ecosystems (9 grasslands and 10 forests) at the plot-scale. Here, dew duration was calculated for each night based on the difference between the surface temperature and the dew point temperature of the air. The results from this analysis show that dew duration is limited by wind speed during the night, with a maximum dew yield at 1.1 m/s and no dew occurrence when the wind speed exceeds 7 m/s. This observation is consistent with previous studies but has been expanded here across multiple biomes to produce a well-defined turbulent limit on dew formation. The sensitivity of dew to wind speed arises because of the exhaustion of the water vapor supply close to the surface of the leaf at very low wind speed, and because the enhanced thermal exchange between the air and the surface counteracts dewfall at high wind speed. This well-defined wind speed limit that persists across sites and seasons could help to estimate the surface energy budget at night by constraining the latent heat flux.

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

Science.gov (United States)

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.

Relationship between relative humidity and the dew point ...

African Journals Online (AJOL)

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

Acid dew point measurements in combustion gases using the dew point measuring system AH 85100

Energy Technology Data Exchange (ETDEWEB)

Fehler, D.

1984-01-01

Measuring system for continuous monitoring of the SO/sub 2//SO/sub 3/ dew point in the flue gas, characterized by a low failure rate, applicability inside the flue gas duct, maintenance-free continuous operation, and self-cleaning. The measuring principle is the cooling of the sensor element down to the 'onset condensation' message. Sensor surface temperatures are listed and evaluated as flue gas dew point temperatures. The measuring system is described. (DOMA).

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

Science.gov (United States)

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

2012-12-01

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

Estimation of precipitable water from surface dew point temperature

International Nuclear Information System (INIS)

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

1991-09-01

The Reitan (1963) regression equation which is of the form lnw=a+bT d has been examined and tested to estimate precipitable water content from surface dew point temperature at different locations. The study confirms that the slope of this equation (b) remains constant at the value of .0681 deg. C., while the intercept (a) changes rapidly with the latitude. The use of the variable intercept can improve the estimated result by 2%. (author). 6 refs, 4 figs, 3 tabs

The dew point temperature as a criterion for optimizing the operating conditions of proton exchange membrane fuel cells

DEFF Research Database (Denmark)

Berning, Torsten

2012-01-01

In this article an analytical method to calculate the dew point temperatures of the anode and cathode exit gas streams of a proton exchange membrane fuel cell is developed. The results of these calculations are used to create diagrams that show the dew point temperatures as function of the operat...... for conventional flow field plates. The diagrams presented here are created for completely dry inlet gases, but they can be easily corrected for a nonzero inlet relative humidity....

A micro dew point sensor with a thermal detection principle

Science.gov (United States)

Kunze, M.; Merz, J.; Hummel, W.-J.; Glosch, H.; Messner, S.; Zengerle, R.

2012-01-01

We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ~1 µm3) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of -20 °C (air temperature = 22 °C) the deviation increases to nearly -1 K.

A micro dew point sensor with a thermal detection principle

International Nuclear Information System (INIS)

Kunze, M; Merz, J; Glosch, H; Messner, S; Zengerle, R; Hummel, W-J

2012-01-01

We present a dew point temperature sensor with the thermal detection of condensed water on a thin membrane, fabricated by silicon micromachining. The membrane (600 × 600 × ∼1 µm 3 ) is part of a silicon chip and contains a heating element as well as a thermopile for temperature measurement. By dynamically heating the membrane and simultaneously analyzing the transient increase of its temperature it is detected whether condensed water is on the membrane or not. To cool the membrane down, a peltier cooler is used and electronically controlled in a way that the temperature of the membrane is constantly held at a value where condensation of water begins. This temperature is measured and output as dew point temperature. The sensor system works in a wide range of dew point temperatures between 1 K and down to 44 K below air temperature. In experimental investigations it could be proven that the deviation of the measured dew point temperatures compared to reference values is below ±0.2 K in an air temperature range of 22 to 70 °C. At low dew point temperatures of −20 °C (air temperature = 22 °C) the deviation increases to nearly −1 K

Smart textile plasmonic fiber dew sensors.

Science.gov (United States)

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.

Calibration of Relative Humidity Sensors using a Dew Point Generator

OpenAIRE

Brooks, Milo

2010-01-01

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

Dew-point measurements at high water vapour pressure

Science.gov (United States)

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.

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

Science.gov (United States)

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.

A New Primary Dew-Point Generator at TUBITAK UME

Science.gov (United States)

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.

Development of Bioclimatic Design Tool for Oman Using Dry Bulb and Dew Point Temperatures Open Database

Directory of Open Access Journals (Sweden)

Nasser Al-Azri

2017-06-01

Full Text Available Bioclimatic charts are used by engineers and architects in implementing passive cooling systems and architectural optimization with respect to natural air conditioning. Conventionally, the development of these charts is based on the availability of typical meteorological year which requires a record of meteorological data that are rarely available in sufficient amounts. Bioclimatic charts in Oman were developed earlier by the authors for limited locations based on the available typical meteorological years. Using dry bulb and dew point temperatures only, bioclimatic charts are developed for Adam, Buraimi, Ibra, Muscat, Nizwa, Rustaq, Saiq, Salalah, Suhar and Sur. These charts are better representative of bioclimatic trends since their development is mainly based on the relevant parameters, namely dry bulb temperature and dew point.

Multi-channel fiber optic dew and humidity sensor

Science.gov (United States)

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

2018-03-01

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

Control of dew and frost formation on leaf by radiative cooling

International Nuclear Information System (INIS)

Matsui, T.; Eguchi, H.; Mori, K.

1981-01-01

A radiative cooling system was developed to control dew and frost formations and to examine the effect of the radiative cooling on the leaf temperature. The growth chamber was provided with a box which was constructed by using heat insulating materials to minimize the disturbances and to regulate the air current. A cooling coil (cooling surface of 300 cm was equipped at the bottom of the box and manipulated by a refrigerator of 1, 430 kcal hour -1 , and a concave mirror was attached to the ceiling of the box to facilitate the reflection of the radiation from the leaf to the cooling coil. The moisture in air was supplied by flowing the controlled air (0.2 m min -1 ) into the box. The distribution of dew point temperatures was almost uniform horizontally even under vertically slight conversion (downward velocity of 1.3 cm sec -1 ) of the air. The leaf temperature became about 1.0°C lower than the ambient air temperature under the radiative cooling. The dew and the frost were clearly observed on the leaf after the time when the leaf temperature had become lower than the dew point temperature. The dew increased in size in course of time, and the frost varied in shape and in size with the temperatures. Thus, artificial formations of the dew and the frost were made possible by the radiative cooling system developed in this experiment

Dew measurement and estimation of rain-fed jujube (Zizyphus jujube Mill) in a semi-arid loess hilly region of China

Institute of Scientific and Technical Information of China (English)

WANG Xing; GAO Zhiyong; WANG Youke; Wang Zhi; JIN Shanshan

2017-01-01

Dew is an important water source for plants in arid and semi-arid regions.However,information on dew is scarce in such regions.In this study,we explored dew formation,amount,and duration of rain-fed jujube (Zi（w）phus jujube Mill) trees in a semi-arid loess hilly region of China (i.e.,Mizhi County).The data included dew intensity and duration,relative humidity,temperature,and wind speed measured from 26 July to 23 October,2012 and from 24 June to 17 October,2013 using a micro-climate system (including dielectric leaf wetness sensors,VP-3 Relative Humidity/Temperature Sensor,High Resolution Rain Gauge,and Davis Cup Anemometer).The results show that atmospheric conditions of relative humidity of ＞78％ and dew point temperature of 1℃C-3℃C are significantly favorable to dew formation.Compared with the rainfall,dew was characterized by high frequency,strong stability,and long duration.Furthermore,heavy dew accounted for a large proportion of the total amount.The empirical models (i.e.,relative humidity model (RH model) and dew point depression model (DPD model)) for daily dew duration estimation performed well at 15-rain intervals,with low errors ranging between 1.29 and 1.60 h,respectively.But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model.For rain-fed jujube trees in the semi-arid loess hilly regions of China,the optimal threshold of relative humidity was 78％,and the optimal upper and lower thresholds of dew point depression were 1℃C and 5℃C,respectively.The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales.

Monthly variations of dew point temperature in the coterminous United States

Science.gov (United States)

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.

A new steel with good low-temperature sulfuric acid dew point corrosion resistance

Energy Technology Data Exchange (ETDEWEB)

Cheng, X.Q.; Li, X.G. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Key Laboratory of Corrosion and Protection (Ministry of Education), Beijing (China); Sun, F.L. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Lv, S.J. [Corrosion and Protection Center, University of Science and Technology Beijing (China); Equipment and Power Department, Shijiazhuang Refine and Chemical Company Limited, SINOPEC, Shijiazhuang (China)

2012-07-15

In this work, new steels (1, 2, and 3) were developed for low-temperature sulfuric acid dew point corrosion. The mass loss rate, macro- and micro-morphologies and compositions of corrosion products of new steels in 10, 30, and 50% H{sub 2}SO{sub 4} solutions at its corresponding dew points were investigated by immersion test, scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). The results indicated that mass loss rate of all the tested steels first strongly increased and then decreased as H{sub 2}SO{sub 4} concentration increased, which reached maximum at 30%. Corrosion resistance of 2 steel is the best among all specimens due to its fine and homogeneous morphologies of corrosion products. The electrochemical corrosion properties of new steels in 10 and 30% H{sub 2}SO{sub 4} solutions at its corresponding dew points were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated that corrosion resistance of 2 steel is the best among all the experimental samples due to its lowest corrosion current density and highest charge transfer resistance, which is consistent with the results obtained from immersion tests. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

Science.gov (United States)

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.

Continuous acid dew point measurement in coal-fired power plants; Kontinuierliche Saeuretaupunktmessung in Braunkohlekraftwerken

Energy Technology Data Exchange (ETDEWEB)

Foedisch, Holger; Schulz, Joerg; Schengber, Petra; Dietrich, Gabriele [Dr. Foedisch Umweltmesstechnik AG, Markranstaedt (Germany)

2009-07-01

The reduction of flue gas losses is one option to increase power plant efficiency. The target is the optimised low waste gas temperature. When applying lignite and other high-sulphur fuels the temperature of the flue gas is mainly determined by the acid dew point. Temperature of the flue gas system is to amount some 10 to 20 K above the assumed acid dew point. The acid dew point measuring system AMD 08 is able to detect the real acid dew point in a quasi-continuous way. Thus, it is possible to deliberately decrease waste gas temperature. (orig.)

Influence of the burning point on the dew point in a diesel engine

Energy Technology Data Exchange (ETDEWEB)

Teetz, C.

1982-06-01

A computation on the influence of the ignition point on the dew point in a cylinder of a diesel engine is presented. The cylinder-pressure diagrams are shown. The results of computation are given. A later ignition point diminishes the area with cylinder wall temperatures below the dew point. The endangering by cylinder wall temperatures below the dew point is illustrated.

Experimental investigation of a super performance dew point air cooler

International Nuclear Information System (INIS)

Xu, Peng; Ma, Xiaoli; Zhao, Xudong; Fancey, Kevin

2017-01-01

Highlights: •The cooler had a complex heat & mass exchanger with an advanced wet material layer. •Intermittent water supply scheme was implemented. •The cooler achieved 100–160% higher COP compared to the existing dew point coolers. •Electricity use of the cooler was reduced by 50–70% compared to existing dew coolers. •This optimal working air ratio was 0.364 that enabled maximised cooling effectiveness. -- Abstract: This paper presents an experimental investigation of a super performance dew point air cooler which, by employing a super performance wet material layer, innovative heat and mass exchanger and intermittent water supply scheme, has achieved a significantly higher energy efficiency (i.e. Coefficient of Performance, COP) and a much lower electrical energy use compared to the existing air coolers of the same type. This involves the dedicated system design & construction, fully planned experimental testing under various simulated climatic conditions representing the climate of hot & dry, warm & dry, moderate, warm & humid and standard lab testing condition, testing results analysis and discussion, as well as the parallel comparison against the commercial dew point air cooler. Under the standard test condition, i.e. dry bulb temperature of 37.8 °C and coincident wet bulb temperature of 21.1 °C, the prototype cooler achieved the wet-bulb cooling effectiveness of 114% and dew-point cooling effectiveness of 75%, yielding a significantly high COP value of 52.5 at the optimal working air ratio of 0.364. The testing also indicated that the lower inlet air relative humidity led to a higher cooling efficiency, while the lower cooling output helped increase COP and cooling effectiveness (including the wet-bulb effectiveness and dew-point effectiveness) of the cooler.

Predicting acid dew point with a semi-empirical model

International Nuclear Information System (INIS)

Xiang, Baixiang; Tang, Bin; Wu, Yuxin; Yang, Hairui; Zhang, Man; Lu, Junfu

2016-01-01

Highlights: • The previous semi-empirical models are systematically studied. • An improved thermodynamic correlation is derived. • A semi-empirical prediction model is proposed. • The proposed semi-empirical model is validated. - Abstract: Decreasing the temperature of exhaust flue gas in boilers is one of the most effective ways to further improve the thermal efficiency, electrostatic precipitator efficiency and to decrease the water consumption of desulfurization tower, while, when this temperature is below the acid dew point, the fouling and corrosion will occur on the heating surfaces in the second pass of boilers. So, the knowledge on accurately predicting the acid dew point is essential. By investigating the previous models on acid dew point prediction, an improved thermodynamic correlation formula between the acid dew point and its influencing factors is derived first. And then, a semi-empirical prediction model is proposed, which is validated with the data both in field test and experiment, and comparing with the previous models.

A new comparison method for dew-point generators

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Integrated CMOS dew point sensors for relative humidity measurement

Science.gov (United States)

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

2004-07-01

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

Dew point measurements of flue gases in steam generators with brown coal combustion

Energy Technology Data Exchange (ETDEWEB)

Schinkel, W.

1980-01-01

This paper examines empirical data on sulfuric acid condensation and resulting internal corrosion in brown coal fired steam generators. Due to the high sulfur content in brown coal (0.5% to 5.0%) and relative short duration of the gases in the combustion chamber the concentrations of sulfur trioxide present in the flue gases can condense at the heat exchange surfaces of the steam generators. A number of diagrams show sulfuric acid dew point temperatures depending on brown coal sulfur content, the influence of combustion air supply on the dew point, and condensing speed and the rate of corrosion in relation to different heat exchange surface temperatures. The conclusion is made that a five-fold increase in corrosion can be caused by a 10 K higher flue gas dew point, a 5 K cooling of heating surfaces can also cause heavy corrosion at a certain dew point. Maximum corrosion results at 20 to 50 K differences between flue gas dew point and heat exchange surfaces. Optimum operation of steam generators with minimal internal corrosion requires the consideration of flue gas and heating surface temperatures as well as flue gas sulfur acid dew points. (10 refs.) (In German)

Projected climate change impacts upon dew yield in the Mediterranean basin

Energy Technology Data Exchange (ETDEWEB)

Tomaszkiewicz, M. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Abou Najm, M., E-mail: majdian@aub.edu.lb [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Beysens, D. [Physique et Mecanique des Milieux Heterogenes, UMR 7636 CNRS — ESPCI, Universite Pierre et Marie Curie — Universite Paris Diderot, 10 rue Vauquelin, 75005 Paris (France); Service des Basses Temperatures, CEA-Grenoble & Universite Joseph Fourier, Grenoble (France); OPUR, 60 rue Emeriau, 75015 Paris (France); Alameddine, I. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon); Bou Zeid, E. [Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08540 (United States); El-Fadel, M. [Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Beirut (Lebanon)

2016-10-01

Water scarcity is increasingly raising the need for non-conventional water resources, particularly in arid and semi-arid regions. In this context, atmospheric moisture can potentially be harvested in the form of dew, which is commonly disregarded from the water budget, although its impact may be significant when compared to rainfall during the dry season. In this study, a dew atlas for the Mediterranean region is presented illustrating dew yields using the yield data collected for the 2013 dry season. The results indicate that cumulative monthly dew yield in the region can exceed 2.8 mm at the end of the dry season and 1.5 mm during the driest months, compared to < 1 mm of rainfall during the same period in some areas. Dew yields were compared with potential evapotranspiration (PET) and actual evapotranspiration (ET) during summer months thus highlighting the role of dew to many native plants in the region. Furthermore, forecasted trends in temperature and relative humidity were used to estimate dew yields under future climatic scenarios. The results showed a 27% decline in dew yield during the critical summer months at the end of the century (2080). - Highlights: • Dew atlas for Mediterranean region is presented. • Cumulative dew yields can exceed 2.8 mm at the end of the dry season. • Dew yields compared with PET and ET show the role of dew to many native plants. • Forecasted trends under future climatic scenarios show a 27% decline in dew yield.

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

Science.gov (United States)

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

A microwave resonance dew-point hygrometer

Science.gov (United States)

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.

A microwave resonance dew-point hygrometer

International Nuclear Information System (INIS)

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

2012-01-01

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. (paper)

Theory of acid deposition and its application to the dew-point meter

Energy Technology Data Exchange (ETDEWEB)

Land, T.

1977-06-01

The theory of convective mass transfer is used to calculate the rate of deposition of sulphuric acid on cooled surfaces in boiler flues. The mass deposited per unit area per second is ah/c (p/sub Ag/ - p/sub As/) where h is the coefficient of convective heat transfer, c is the specific heat of the gas and a is a factor having a value of about 1.9; p/sub Ag/ and p/sub As/ are the partial pressures of sulphuric acid in the bulk of the gas and in saturated gas at the temperature of the surface. Values of p/sub A/ are tabulated against dew-point temperature and water vapour content. The theory explains how fog formation in the gas reduces the rate of acid deposition within a certain band of temperature between the acid dew-point and the water dew-point. The rate of deposition on a probe is shown to depend on the local mass flow as well as on the acid content. By contrast the dew-point depends only on the acid content. The sensitivity of the dew-point meter to changes in acid content is not very high but it is adequate for the control of combustion. A continuously recording dew-point meter is being successfully used on industrial boilers.

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

Science.gov (United States)

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.

A quartz crystal microbalance dew point sensor without frequency measurement

Science.gov (United States)

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.

Dew point of flue gas in the combustion of brown coal briquettes

Energy Technology Data Exchange (ETDEWEB)

Schinkel, W

1977-08-01

Economical operation of small steam generators can follow two courses, viz. to channel the emitted gases through the plant and reduce waste gas loss. Two possibilities exist to achieve this: firstly a steam generating process with only slight excess air; secondly a reduction of the emitted gas temperature. The lowest waste gas temperature found in sulphur-containing combustion materials is measured by finding the acid dew-point of the waste gas. The following results in the case of brown coal briquettes were found. Measurements of the dew point of flue gas in two steam generators, both of the double flue type, one having a capacity of 12.5 t/h, the other 25 t/h, one using brown coal briquettes with 1% sulphur content, the other with 3%, resulted in the fact that the dew point can be measured. It was shown that a low air ratio leads to a lowering of the dew point. However this process is unfortunately economically unviable in chain grate generators as the waste gas becomes so thin under a high air ratio that the dew point can only be minimally reduced. Further the acid dew point is only slightly influenced by partial operation of the generator and the infusion of briquette residue.

Experimental study of influence characteristics of flue gas fly ash on acid dew point

Science.gov (United States)

Song, Jinhui; Li, Jiahu; Wang, Shuai; Yuan, Hui; Ren, Zhongqiang

2017-12-01

The long-term operation experience of a large number of utility boilers shows that the measured value of acid dew point is generally lower than estimated value. This is because the influence of CaO and MgO on acid dew point in flue gas fly ash is not considered in the estimation formula of acid dew point. On the basis of previous studies, the experimental device for acid dew point measurement was designed and constructed, and the acid dew point under different smoke conditions was measured. The results show that the CaO and MgO in the flue gas fly ash have an obvious influence on the acid dew point, and the content of the fly ash is negatively correlated with the temperature of acid dew point At the same time, the concentration of H2SO4 in flue gas is different, and the acid dew point of flue gas is different, and positively correlated with the acid dew point.

Characterization of Emericella nidulans RodA and DewA hydrophobin mutants

DEFF Research Database (Denmark)

Jensen, Britt Guillaume; Nielsen, Jakob Blæsbjerg; Pedersen, Mona Højgaard

hydrophobins RodA and DewA. Individual knock-out mutants rodAΔ, dewAΔ and the double deletion strain rodAΔdewAΔ were constructed. Furthermore, two strains containing a point mutation in the first of the cysteines of RodA (rodA-C57G), where one was coupled to the dewA deletion, were included. The reference...... strain (NID1) and dewAΔ displayed green conidia. However, rodAΔ and rodAΔdewAΔ showed a dark green/brown conidial pigmentation, while rodA-C57G and rodAC57G dewAΔ displayed lighter brown conidia. rodAΔ and rodAΔdewAΔ displayed a higher degree of hülle cells compared to the moderate amount observed...... for NID1 and dewAΔ, while rodA-C57G and rodA-C57G dewAΔ displayed a low number of hülle cells. NID1 and dewAΔ conidia were dispersed as spore chains. rodAΔ, rodAΔdewAΔ, rodA-C57G and rodA-C57G dewAΔ spores were associated in large clumps, where the conidia seemed to adhere to one another. The largest...

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

Science.gov (United States)

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.

Measuring the exhaust gas dew point of continuously operated combustion plants

Energy Technology Data Exchange (ETDEWEB)

Fehler, D.

1985-07-16

Low waste-gas temperatures represent one means of minimizing the energy consumption of combustion facilities. However, condensation should be prevented to occur in the waste gas since this could result in a destruction of parts. Measuring the waste-gas dew point allows to control combustion parameters in such a way as to be able to operate at low temperatures without danger of condensation. Dew point sensors will provide an important signal for optimizing combustion facilities.

Phase-equilibria for design of coal-gasification processes: dew points of hot gases containing condensible tars. Final report

Energy Technology Data Exchange (ETDEWEB)

Prausnitz, J.M.

1980-05-01

This research is concerned with the fundamental physical chemistry and thermodynamics of condensation of tars (dew points) from the vapor phase at advanced temperatures and pressures. Fundamental quantitative understanding of dew points is important for rational design of heat exchangers to recover sensible heat from hot, tar-containing gases that are produced in coal gasification. This report includes essentially six contributions toward establishing the desired understanding: (1) Characterization of Coal Tars for Dew-Point Calculations; (2) Fugacity Coefficients for Dew-Point Calculations in Coal-Gasification Process Design; (3) Vapor Pressures of High-Molecular-Weight Hydrocarbons; (4) Estimation of Vapor Pressures of High-Boiling Fractions in Liquefied Fossil Fuels Containing Heteroatoms Nitrogen or Sulfur; and (5) Vapor Pressures of Heavy Liquid Hydrocarbons by a Group-Contribution Method.

Dew Point modelling using GEP based multi objective optimization

OpenAIRE

Shroff, Siddharth; Dabhi, Vipul

2013-01-01

Different techniques are used to model the relationship between temperatures, dew point and relative humidity. Gene expression programming is capable of modelling complex realities with great accuracy, allowing at the same time, the extraction of knowledge from the evolved models compared to other learning algorithms. We aim to use Gene Expression Programming for modelling of dew point. Generally, accuracy of the model is the only objective used by selection mechanism of GEP. This will evolve...

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

Science.gov (United States)

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.

Flue gas heat recovery operating below the dew point and its utilisation for low temperature heating installations

Energy Technology Data Exchange (ETDEWEB)

Wilsdorf, J.

1986-11-01

This paper deals at first with the characteristics of two principal systems for the flue gas heat recovery by reducing the temperature below the dew point. With test results on experimental plants are shown the typical differences between surface and direct contact heat exchange. A second part informs about experiences from the application for low temperature heating installations, especially about thermodynamics condensate quality and technical design. The possible increasing of the efficiency ranges between 10 to 20 per cent.

TFOS DEWS II Report Executive Summary.

Science.gov (United States)

Craig, Jennifer P; Nelson, J Daniel; Azar, Dimitri T; Belmonte, Carlos; Bron, Anthony J; Chauhan, Sunil K; de Paiva, Cintia S; Gomes, José A P; Hammitt, Katherine M; Jones, Lyndon; Nichols, Jason J; Nichols, Kelly K; Novack, Gary D; Stapleton, Fiona J; Willcox, Mark D P; Wolffsohn, James S; Sullivan, David A

2017-10-01

This article presents an Executive Summary of the conclusions and recommendations of the 10-chapter TFOS DEWS II report. The entire TFOS DEWS II report was published in the July 2017 issue of The Ocular Surface. A downloadable version of the document and additional material, including videos of diagnostic and management techniques, are available on the TFOS website: www.TearFilm.org. Copyright © 2017 Elsevier Inc. All rights reserved.

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

Directory of Open Access Journals (Sweden)

Ningning Lin

2016-11-01

Full Text Available 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 variability in three habitats of a sand dune transect in a desert oasis ecotone, Northwestern China

CERN Document Server

Zhuang, Yanli

2014-01-01

Dew, as a supplementary water source, may have an important ecological role in arid and semi-arid regions. During August and September of 2007 and 2008, measurements were taken to investigate the dew accumulation and evaporation patterns in the very early morning hours, in three different habitats (dunetop, footslope, and interdune lowland) of a fixed sand dune in Northwest China. Dew quantities were measured using the cloth-plate method. The results indicated that there was a positive correlation between dew amounts and relative humidity, but a negative correlation between dew amounts and mean temperature. Clear mornings were characterized by higher dew amounts and longer dew duration, whereas less dew was recorded during cloudy and especially windy mornings. Dew continued to condense even after sunrise, although a shorter warming time after dawn is also of vital importance in dew formation. The higher average maximum dew quantities (0.06mm) and longer average dew duration (2.3h) occurred in the interdune lo...

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

Science.gov (United States)

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.

Method and apparatus for continuously detecting and monitoring the hydrocarbon dew-point of gas

Energy Technology Data Exchange (ETDEWEB)

Boyle, G.J.; Pritchard, F.R.

1987-08-04

This patent describes a method and apparatus for continuously detecting and monitoring the hydrocarbon dew-point of a gas. A gas sample is supplied to a dew-point detector and the temperature of a portion of the sample gas stream to be investigated is lowered progressively prior to detection until the dew-point is reached. The presence of condensate within the flowing gas is detected and subsequently the supply gas sample is heated to above the dew-point. The procedure of cooling and heating the gas stream continuously in a cyclical manner is repeated.

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

Science.gov (United States)

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.

Numerical study of a novel counter-flow heat and mass exchanger for dew point evaporative cooling

Energy Technology Data Exchange (ETDEWEB)

Zhao, X.; Riffat, S.B. [School of the Built Environment, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Li, J.M. [Department of Thermal Engineering, Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)

2008-10-15

The paper presents numerical investigation of a novel counter-flow heat and mass exchanger used in the indirect evaporative dew point cooling systems, a potential alternative to the conventional mechanical compression air conditioning systems. Numeric simulation was carried out to optimise the geometrical sizes and operating conditions of the exchanger in order to enhance the cooling (dew point and wet bulb) effectiveness of the exchanger and maximise the energy efficiency of the dew point cooling system. The results of the simulations indicated that cooling (dew point and wet bulb) effectiveness and energy efficiency are largely dependent on the dimensions of the airflow passages, air velocity and working-to-intake-air ratio, and less dependent on the temperature of the feed water. It is recommended that exchanger intake air velocity should be controlled to a value below 0.3-0.5 m/s; height of air passage (channel) should be set to 6 mm or below and the length of the passage should be 200 time the height; the working-to-intake-air ratio should be around 0.4. Under the UK summer design condition, i.e., 28{sup o}C of dry bulb temperature, 20{sup o}C of wet bulb temperature and 16{sup o}C of dew point temperature, the exchanger can achieve wet-bulb effectiveness of up to 1.3 and dew-point effectiveness of up to 0.9. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.Z.; Chu, Y.

1986-01-01

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

Correlation of dew- and bubble-point curves for binary refrigerant mixtures. [Correlation between dew-point pressure(saturated vapor state) and bubble-point pressure(saturated liquid state)]. Niseibunkei kongo reibai no roten oyobi futten kyokusen no sokan

Energy Technology Data Exchange (ETDEWEB)

Yada, N. (Kanagawa Institute of Technology, Kanagawa (Japan)); Watanabe, K. (Keio University, Tokyo (Japan). Faculty of Science and Technology)

1991-12-25

The paper makes a correlation expressing dew- and bubble-point curves using measured values for seven binary refrigerant freon-mixtures. In most binary systems at the same temperature, the pressure shows a different value between in a saturated vapor state (dew-point pressure) and in a saturated liquid state (bubble-point pressure). The target is such correlation as has as simple a function form as possible and is able to estimate even near the critical point where it used to be difficult to estimate. The pressure difference between measured values of the dew- and bubble-point pressure and values calculated from Raoult's law showing an ideal mixture of fluid is expressed by a simple function form of reduced temperature Tr and molar fraction. Tr is thermodynamic temperature/critical temperature. Reproducibility of this correlation is less than {plus minus}3% of the pressure deviation. Concerning also the arbitary composition range and near the critical point, the dew- and bubble-point pressure can be calculated accurately. 24 refs., 4 figs., 5 tabs.

Study of the influence of the cool-down speed at the dew-point level of the readings of the dew-point temperature; Untersuchungen zum Einfluss der Abkuehlgeschwindigkeit am Taupunktspiegel auf Messwerte der Taupunkttemperatur

Energy Technology Data Exchange (ETDEWEB)

Bogoya, J.D. [Univ. Nacional de Colombia (Colombia); Mueller, C. [Inst. fuer Technische Thermodynamik und Kaeltetechnik, Univ. Karlsruhe (Germany); Oellrich, L.R. [Inst. fuer Technische Thermodynamik und Kaeltetechnik, Univ. Karlsruhe (Germany)

1995-09-01

The impact of the cool-down speed at the dew-point mirror on the behaviour of the readings of dew-point temperature of nitrogen-water mixtures has been investigated with the focus on mixtures with low water content. For this purpose a commercial dew-point mirror was equipped with a refrigerating device in order to cool the mirror surface. Moreover a data acquisition system was connected for the measurement of the rates of cooling. Via a control valve in the refrigerant cycle rates of cooling of about 1 to 35 C/min could be chosen. With a saturation system saturation conditions could be varied in the pressure range from 5 to 90 bar and in the temperature range from +10 to -15 C. The measuring instrument was continuously supplied with the gas mixture. The measurements were carried out under constant volume flow of the carrier gas. The results are discussed. (orig.) [Deutsch] Der Einfluss der Abkuehlgeschwindigkeit am Taupunktspiegel auf die Lage der Messwerte der Taupunkttemperaturen von Stickstoff/Wasser-Gemischen wurde speziell im Bereich niedriger Wassergehalte untersucht. Dazu wurde ein kommerzieller Taupunktspiegel zur Kuehlung der Spiegeloberflaeche mit einer Kaeltemaschine ausgestattet und eine Messwerterfassung, mit der Abkuehlgeschwindigkeiten ermittelt werden konnte, angeschlossen. Ueber ein Regelventil im Kaeltemittelkreislauf konnten Abkuehlgeschwindigkeiten von ca. 1 bis 35 C/min eingestellt werden. Ueber eine Saettigungsanlage wurden Saettigungsbedingungen im Druckbereich von 5 bis 90 bar und im Temperaturbereich von +10 bis -15 C variiert und das Messgeraet kontinuierlich mit Gasgemisch versorgt. Die Messungen wurden bei konstantem Volumenstrom des Traegergases durchgefuehrt. Die Messergebisse werden diskutiert. (orig.)

An experimental study of a novel dew point evaporative cooling system

Energy Technology Data Exchange (ETDEWEB)

Riangvilaikul, B.; Kumar, S. [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120 (Thailand)

2010-05-15

A novel dew point evaporative cooling system for sensible cooling of the ventilation air for air conditioning application was constructed and experiments were carried out to investigate the outlet air conditions and the system effectiveness at different inlet air conditions (temperature, humidity and velocity) covering dry, temperate and humid climates. The results showed that wet bulb effectiveness ranged between 92 and 114% and the dew point effectiveness between 58 and 84%. A continuous operation of the system during a typical day of summer season in a hot and humid climate showed that wet bulb and dew point effectiveness were almost constant at about 102 and 76%, respectively. The experiment results were compared with some recent studies in literature. (author)

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

Science.gov (United States)

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.

Acid dew point measurement in flue gases

Energy Technology Data Exchange (ETDEWEB)

Struschka, M.; Baumbach, G.

1986-06-01

The operation of modern boiler plants requires the continuous measurement of the acid dew point in flue gases. An existing measuring instrument was modified in such a way that it can determine acid dew points reliably, reproduceably and continuously. The authors present the mechanisms of the dew point formation, the dew point measuring principle, the modification and the operational results.

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

Science.gov (United States)

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.

STUDY ON THE DEW POINT TEMPERATURE IN AREAS WITH SUPERFICIAL LIMESTONE UNDERGROUND ENVIRONMENT (SCREE IN THE GHIMBAV AREA, LEAOTA MOUNTAINS, 2014

Directory of Open Access Journals (Sweden)

Magdalin-Leonard Dorobăţ

2015-07-01

Full Text Available The dew point of a mixture of a gas (air and the water vapors represents the temperature at which the cold air becomes saturated in water vapors and they condensate. Sometimes, especially in colder periods, it is more revealing regarding the water quantity in the air as vapors, than the relative humidity indicator. The field observations have shown that, always, in the surveys in the ecologic stationaries I have installed in limestone scree in Leaota Massive, condense is formed on the walls of the PVC tubes, irrespective of the season. The continuous measuring, for a period of several months, of more abiotic parameters, amongst which the temperature of the dew point was carried out with dataloggers, which were installed at different depths in limestone scree. This type of continuous monitoring of abiotic parameters at different scree depths is a premiere for Leaota and even is a first for Romania.

Mechanism research on coupling effect between dew point corrosion and ash deposition

International Nuclear Information System (INIS)

Wang, Yun-Gang; Zhao, Qin-Xin; Zhang, Zhi-Xiang; Zhang, Zhi-Chao; Tao, Wen-Quan

2013-01-01

In order to study the coupling mechanism between ash deposition and dew point corrosion, five kinds of tube materials frequently used as anti-dew point corrosion materials were selected as research objects. Dew point corrosion and ash deposition experiments were performed with a new type experimental device in a Chinese thermal power plant. The microstructures of the materials and the composition of ash deposition were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS). The results showed that the ash deposition layer could be divided into non-condensation zone, the main condensation zone and the secondary condensation zone. The acid vapor condensed in the main condensation zone rather than directly on the tube wall surface. The dew point corrosion mainly is oxygen corrosion under the condition of the viscosity ash deposition, and the corrosion products are composed of the ash and acid reaction products in the outer layer, iron sulfate in the middle layer, and iron oxide in the inner layer. The innermost layer is the main corrosion layer. With the increase of the tube wall temperature, the ash deposition changes from the viscosity ash deposition to the dry loose ash deposition, the ash deposition rate decreases dramatically and dew point corrosion is alleviated efficiently. The sulfuric dew point corrosion resistance of the five test materials is as follows: 316L > ND > Corten>20G > 20 steel. -- Highlights: ► Dew point corrosion and ash deposition tests of five materials were performed. ► Acid vapor condensed in the ash deposit rather than directly on the tube surface. ► Dew point corrosion resistance is as follow: 316L > ND > Corten>20G > 20 steel. ► Dew point corrosion mainly is oxygen corrosion under viscosity ash deposition

Verification of alternative dew point hygrometer for CV-LRT in MONJU. Short- and long-term verification of capacitance-type dew point hygrometer (Translated document)

International Nuclear Information System (INIS)

Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo; Inuzuka, Taisuke; Kitano, Hiroshi; Abe, Hisashi

2017-03-01

To reduce the influence of maintenance of dew point hygrometers on the plant schedule at the prototype fast-breeder reactor MONJU, Japan Atomic Energy Agency examined a capacitance-type dew point hygrometer as an alternative to the lithium-chloride dew point hygrometer being used in the containment vessel leak rate test. As verifications, a capacitance-type dew point hygrometer was compared with a lithium-chloride dew point hygrometer under a containment vessel leak rate test condition. And the capacitance-type dew point hygrometer was compared with a high-precision-mirror-surface dew point hygrometer for long-term (2 years) in the containment vessel as an unprecedented try. A comparison of a capacitance-type dew point hygrometer with a lithium-chloride dew point hygrometer in a containment vessel leak rate test (Atmosphere: nitrogen, Testing time: 24 h) revealed no significant difference between the capacitance-type dew point hygrometer and the lithium-chloride dew point hygrometer. A comparison of the capacitance-type dew point hygrometer with the high-precision-mirror-surface dew point hygrometer for long-term verification (Atmosphere: air, Testing time: 24 months) revealed that the capacitance-type dew point hygrometer satisfied the instrumental specification (synthesized precision of detector and converter: ±2.04°C) specified in the Leak Rate Test Regulations for Nuclear Reactor Containment Vessel. It was confirmed that the capacitance-type dew point hygrometer can be used as a long-term alternative to the lithium-chloride dew point hygrometer without affecting the dew point hygrometer maintenance schedule of the MONJU plant. (author)

Tar dew point analyser as a tool in biomass gasification

Energy Technology Data Exchange (ETDEWEB)

Vreugdenhil, B.J.; Kuipers, J. [ECN Biomass, Coal and Environmental Research, Petten (Netherlands)

2008-08-15

Application of the Tar Dew point Analyzer (TDA) in different biomass based gasification systems and subsequent gas cleaning setups has been proven feasible. Such systems include BFB gasifiers, CFB gasifier and fixed bed gasifiers, with tar crackers or different scrubbers for tar removal. Tar dew points obtained with the TDA give direct insight in the performance of the gas cleaning section and help prevent any tar related problems due to condensation. The current TDA is capable of measuring tar dew points between -20 to 200C. This manuscript will present results from 4 different gasification setups. The range of measured tar dew points is -7 to 164C with comparable results from the calculated dew points based on the SPA measurements. Further detail will be presented on the differences between TDA and SPA results and explanations will be given for deviations that occurred. Improvements for the TDA regarding future work will be presented.

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

Science.gov (United States)

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

Study and realization of a new humid air generator; towards the definition of a dew temperature reference; Etude et realisation d'un nouveau generateur d'air humide; vers la definition d'une reference en temperature de rosee

Energy Technology Data Exchange (ETDEWEB)

Blanquart, B.

2001-03-01

The air humidity is an important parameter for several biological and physico-chemical processes. The aim of this thesis is the direct determination of the dew temperature without any link with the gravimetric reference. This document presents the realization and adjusting of a new humid air generator for the -80 deg. C to +15 deg. C range and the uncertainty linked with the dew temperature of the humid air generated. The first chapter recalls the definitions of humid air related data and the principles of the apparatuses used for the measurement of air humidity. The second chapter deals with temperature measurements while chapter 3 describes the new humid air generator built around an 'ideal' cell based on the theoretical definition of the dew temperature. Technical constraints due to temperature measurement and to hygrometers calibration are progressively integrated and introduced and lead to the practical realization of the device. Differences between the ideal cell and the prototype are estimated using a theoretical approach of mass and heat exchanges coupled with experimental results obtained with a previous prototype. Chapter 4 presents a first status of the device uncertainties with some possibilities of reduction of these uncertainties. (J.S.)

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

Science.gov (United States)

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.

Automatic continuous dew point measurement in combustion gases

Energy Technology Data Exchange (ETDEWEB)

Fehler, D.

1986-08-01

Low exhaust temperatures serve to minimize energy consumption in combustion systems. This requires accurate, continuous measurement of exhaust condensation. An automatic dew point meter for continuous operation is described. The principle of measurement, the design of the measuring system, and practical aspects of operation are discussed.

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

Science.gov (United States)

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).

Winter Dew Harvest in Mexico City

Directory of Open Access Journals (Sweden)

Arias-Torres Jorge Ernesto

2015-12-01

Full Text Available This study presents experimental and theoretical results of winter dew harvest in México City in terms of condensation rate. A simplified theoretical model based on a steady-state energy balance on a radiator-condenser was fitted, as a function of the ambient temperature, the relative humidity and the wind velocity. A glass sheet and aluminum sheet white-painted were used as samples over the outdoor experiments. A good correlation was obtained between the theoretical and experimental data. The experimental results show that there was condensation in 68% of the winter nights on both condensers. The total winter condensed mass was 2977 g/m2 and 2888 g/m2 on the glass sheet and aluminum sheet white-painted, respectively. Thus, the condensed mass on the glass was only 3% higher than that on the painted surface. The maximum nightly dew harvests occurred during December, which linearly reduced from 50 g/m2 night to 22 g/m2 night as the winter months went by. The condensation occurred from 1:00 a.m. to 9:00 a.m., with maximum condensation rates between 6:00 a.m. and 7:00 a.m. The dew harvest can provide a partial alternative to the winter water shortage in certain locations with similar climates to the winter in Mexico City, as long as pollution is not significant.

Unsteady-state analysis of a counter-flow dew point evaporative cooling system

KAUST Repository

Lin, J.

2016-07-19

Understanding the dynamic behavior of the dew point evaporative cooler is crucial in achieving efficient cooling for real applications. This paper details the development of a transient model for a counter-flow dew point evaporative cooling system. The transient model approaching steady conditions agreed well with the steady state model. Additionally, it is able to accurately predict the experimental data within 4.3% discrepancy. The transient responses of the cooling system were investigated under different inlet air conditions. Temporal temperature and humidity profiles were analyzed for different transient and step responses. The key findings from this study include: (1) the response trend and settling time is markedly dependent on the inlet air temperature, humidity and velocity; (2) the settling time of the transient response ranges from 50 s to 300 s when the system operates under different inlet conditions; and (3) the average transient wet bulb effectiveness (1.00–1.06) of the system is observed to be higher than the steady state wet bulb effectiveness (1.01) for our range of study. © 2016 Elsevier Ltd

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Concerning the acid dew point in waste gases from combustion processes

Energy Technology Data Exchange (ETDEWEB)

Knoche, K.F.; Deutz, W.; Hein, K.; Derichs, W.

1986-09-01

The paper discusses the problems associated with the measurement of acid dew point and of sulphuric acid-(say SO/sub 3/-)concentrations in the flue gas from brown coal-fired boiler plants. The sulphuric acid content in brown coal flue gas has been measured at 0.5 to 3 vpm in SO/sub 2/ concentrations of 200 to 800 vpm. Using a conditional equation, the derivation of which from new formulae for phase stability is described in the paper, an acid dew point temperature of 115 to 125/sup 0/C is produced.

Dew Point

OpenAIRE

Goldsmith, Shelly

1999-01-01

Dew Point was a solo exhibition originating at PriceWaterhouseCoopers Headquarters Gallery, London, UK and toured to the Centre de Documentacio i Museu Textil, Terrassa, Spain and Gallery Aoyama, Tokyo, Japan.

Application of passive radiative cooling for dew condensation

International Nuclear Information System (INIS)

Beysens, Daniel; Muselli, Marc; Milimouk, Iryna

2006-01-01

Dew water was collected from several passive foil-based radiative condensers established in a variety of geographic settings: continental (Grenoble, in an alpine valley, and Brive-la-Gaillarde, in the Central Massif volcanic area, both in France), French Atlantic coast (Bordeaux), eastern Mediterranean (Jerusalem, Israel), and the island of Corsica (Ajaccio, France) in the Mediterranean Sea. In Ajaccio two large 30 m 2 condensers have been operating since 2000. Additional semi-quantitative dew measurements were also carried out for Komiza, island of Vis (Croatia) in the Adriatic Sea, and in Mediterranean Zadar and Dubrovnik (both in Croatia). Dew potential was calculated for the Pacific Ocean island of Tahiti (French Polynesia). The data show that significant amounts of dew water can be collected. Selected chemical and biological analyses established that dew is, in general, potable. Continued research is required for new and inexpensive materials that can enhance dew condensation

The Effect of Climate Change on Variations in Dew Amount in a Paddy Ecosystem of the Sanjiang Plain, China

Directory of Open Access Journals (Sweden)

Yingying Xu

2015-01-01

Full Text Available Due to global warming, a drying and warming trend has been observed over the last 50 years in the Sanjiang Plain of Heilongjiang Province, China, which could significantly affect the condensation of vapor in paddy ecosystems. Dew is a crucial factor in the water and nutrient cycling of farmland ecosystems, and it exerts an important influence on fertilization and other agricultural activities. In order to reveal the effects of global warming on dew variation in a paddy ecosystem, an in situ experiment was conducted in paddy fields in the Sanjiang Plain during the growing seasons of 2011 to 2013. Dew was collected and measured with a poplar stick. The results of correlation analysis between meteorological factors and dew intensity in the paddy ecosystem indicate that the dew point temperature and relative humidity significantly influenced the dew intensity. Based on synchronous meteorological data, a stepwise linear multivariation regression model was established to predict dew amount. The model successfully interpreted the relationship between simulated and measured dew intensity. The results suggest that a warmer and drier climate would lead to a reduction in dew amount because water cannot condense when relative humidity falls below 71%.

Fog and dew climatology over Hisar, India

International Nuclear Information System (INIS)

Surender, S.; Diwan, S.; Rao, V.U.M.

2006-05-01

In many arid and semi-arid areas, pumped ground water and the water from streams, rivers and reservoirs is no longer sufficient to cover the ever increasing water demand. Therefore new interest in 'marginal' water resources like fog and dew harvesting are to be developed after studying climatology of these parameters in a region. The observations on dew and fog events recorded at Hisar, representing semi-arid region of India during winter season (October to March) for the period 1980 to 2005 have been analyzed. The total annual dew amount in winter season ranged between 33 mm (1987-88) and 79 mm (1981-82) during the period under study. The seasonal dewfall showed a decreasing trend of 1.4 mm during the period under investigation. Average maximum dew events (26.1) were recorded during November and average minimum dew events were recorded in February. In a particular season, the highest dew events (168) were observed during the winter seasons of 1982-83 and 1983-84, whereas, the minimum number of dew events (97) was reported during 1998-99. Interestingly, an increasing trend (1.3 day/season) in occurrence of fog events was seen. Average maximum foggy events (8.7) recorded in a month were observed in January. In a particular season, the maximum foggy events (41) were recorded during 2002-03 and the minimum (2) during 1983-84. To achieve the objective of alternate source of water and to assess the impact of dew and fog on agricultural crops for their growth and development, inputs from various specialized disciplines and allied sciences engaged in meteorological applications along with forecasting skills from non scientific quarters are needed to predict the weather parameter accurately, thus the active cooperation between meteorological/remote sensing agencies, agricultural organizations and farming community is needed for sustainable agricultural development in scarce/limited water availability regions. (author)

On the contribution of atmospheric moisture to dew formation

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Contribution to the study of sulfur trioxide formation and determination of the sulfuric acid dew point in boiler plants

Energy Technology Data Exchange (ETDEWEB)

Mueller, H.

1983-11-01

This paper analyzes chemical reaction kinetics of the formation of sulfur trioxide and sulfuric acid in combustion air and flue gas of steam generators. Formulae for sulfuric acid equilibrium reactions according to Wahnschaffe (W. Grimm, 1972) and R. Hasse, H.W. Borgmann (1962) are presented. Theoretical acid dew point, combustion parameters with influence on the dew point temperature and formation of sulfates are further discussed. Sulfur trioxide formation at temperatures above 1,000 C as a non-equilibrium reaction is outlined as another variant of chemical reactions. A graphic evaluation is made of dew point conditions in brown coal dust fired, and heating oil fired steam generators. (11 refs.)

STUDY ON THE DEW POINT TEMPERATURE IN AREAS COVERED BY COLLUVIAL MESOVOID SHALLOW SUBSTRATUM (CRYSTALLINE SCHISTS SCREE IN THE LEAOTA MOUNTAINS, 2014

Directory of Open Access Journals (Sweden)

Magdalin Leonard Dorobăţ

2015-12-01

Full Text Available This paper present and discussed the results of the monitoring of the dew point values, recorded in October and November 2014, in an ecological station in the Leaota Mountains. In this station, two polls were located in areas covered by colluvial mesovoid shallow substratum (MSS formed by epi- and mesometamorphic crystalline schists. In the ecological stations we located in the Leaota Mountains, almost always we found condensation on the walls of the polls tubes placed at different depths. Most often in spring or autumn or in other cold days, the dew point is more revealing regarding the recording actual amount of moisture in the air, than the relative humidity indicator. This work is part of a larger project that seeks correlations between ecological factors (humidity, temperature and dew point registered in various types of screes (limestone and crystalline schists and some zoocenotic components (invertebrates. This research aim to know the importance of mesovoid shallow substratum for invertebrates or small vertebrates fauna and represents a premiere for Leaota Mountains, not only regarding the continuous monitoring of some ecologic factors of these types of ecosystems (MSS, rarely researched even at global level, and also regarding the inventory of the invertebrate fauna in scree for these mountains.

Analysis of Multicomponent Adsorption Close to a Dew Point

DEFF Research Database (Denmark)

Shapiro, Alexander; Stenby, Erling Halfdan

1998-01-01

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...... and the direct calculations, even if the mixture is not close to a dew point.Key Words: adsorption; potential theory; multicomponent; dew point....

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

Bubble-point and dew-point equation for binary refrigerant mixture R22-R142b

Energy Technology Data Exchange (ETDEWEB)

Liancheng Tan; Zhongyou Zhao; Yonghong Duan (Xi' an Jiaotong Univ., Xi' an (China). Dept. of Power Machinery Engineering)

1992-01-01

A bubble-point and dew-point equation (in terms either of temperature or of pressure is suggested for the refrigerant mixture R22-R142b), which is regarded as one of the alternatives to R12. This equation has been examined with experimental data. A modified Rackett equation for the calculation of the bubble-point volume is also proposed. Compared with the experimental data, the rms errors in the calculated values of the bubble-point temperature, the dew-point temperature, and the bubble-point volume are 1.093%, 0.947%, and 1.120%, respectively. The calculation covers a wide range of temperatures and pressures, even near the critical point. It is shown how the equations are extrapolated to calculate other binary refrigerant mixtures. (author)

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

Science.gov (United States)

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).

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

Science.gov (United States)

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.

Study on dew point evaporative cooling system with counter-flow configuration

International Nuclear Information System (INIS)

Lin, J.; Thu, K.; Bui, T.D.; Wang, R.Z.; Ng, K.C.; Chua, K.J.

2016-01-01

Highlights: • Numerical model for a dew point evaporative cooler verified with experiments. • Saturation point of the working air is independent of the inlet air conditions. • The intensity of cooling capacity and water evaporation are studied. • The overall heat transfer coefficient for the working air is analyzed. • The conditions to achieve sub-wet bulb cooling are examined. - Abstract: Dew point evaporative cooling has great potential as a disruptive process for sensible cooling of air below its entering wet bulb temperature. This paper presents an improved mathematical model for a single-stage dew point evaporative cooler in a counter-flow configuration. Longitudinal heat conduction and mass diffusion of the air streams, channel plate and water film, as well as the temperature difference between the plate and water film, are accounted for in the model. Predictions of the product air temperature are validated using three sets of experimental data within a discrepancy of 4%. The cooler’s heat and mass transfer process is analyzed in terms of its cooling capacity intensity, water evaporation intensity, and overall heat transfer coefficient along the channel. Parametric studies are conducted at different geometric and operating conditions. For the conditions evaluated, the study reveals that (1) the saturation point of the working air occurs at a fixed point regardless of the inlet air conditions, and it is mainly influenced by the working air ratio and channel height; (2) the intensity of the water evaporation approaches a minimum at 0.2 to 0.3 m from the entrance; (3) the wet channel can be separated into two zones, and the overall heat transfer coefficient is above 100 W/(m"2·K) after the temperature of water film becomes higher than the working air temperature.

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

Science.gov (United States)

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.

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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.

Dew point vs bubble point : a misunderstood constraint on gravity drainage processes

Energy Technology Data Exchange (ETDEWEB)

Nenninger, J. [N-Solv Corp., Calgary, AB (Canada); Gunnewiek, L. [Hatch Ltd., Mississauga, ON (Canada)

2009-07-01

This study demonstrated that gravity drainage processes that use blended fluids such as solvents have an inherently unstable material balance due to differences between dew point and bubble point compositions. The instability can lead to the accumulation of volatile components within the chamber, and impair mass and heat transfer processes. Case studies were used to demonstrate the large temperature gradients within the vapour chamber caused by temperature differences between the bubble point and dew point for blended fluids. A review of published data showed that many experiments on in-situ processes do not account for unstable material balances caused by a lack of steam trap control. A study of temperature profiles during steam assisted gravity drainage (SAGD) studies showed significant temperature depressions caused by methane accumulations at the outside perimeter of the steam chamber. It was demonstrated that the condensation of large volumes of purified solvents provided an efficient mechanism for the removal of methane from the chamber. It was concluded that gravity drainage processes can be optimized by using pure propane during the injection process. 22 refs., 1 tab., 18 figs.

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

Science.gov (United States)

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

Energy Technology Data Exchange (ETDEWEB)

Cesar, Maria das Gracas M.M. E-mail: gracamelo@acesita.com.br; 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.

New correlation of dew point temperature for gases with low H/sub 2/SO/sub 4/ content

Energy Technology Data Exchange (ETDEWEB)

Fieg, J.

1986-04-01

During the last years increased concern about pollution problems has encouraged the development of many methods to remove particulate and other undesirable substances from flue gases. These efforts have also brought renewed interest in aqueous sulfuric acid vapour-liquid equilibrium for predicting the flue gas dew point. This article presents the principal methods, contributing to solve the inherent problems and summarizes the available data and presents a new empirical correlation of the dew point as a function of the partial pressures of sulfuric acid and the water in the vapour.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

Automatic dew-point hygrometer making use of US -ray backscattering and controlled at the constant amount of dew

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Shigeaki; Kobayashi, Hisanobu

1988-08-01

A control system which consists of proportional and integral control to maintain the constant amount of dew was developed in this hygrometer. The dew points were measured within an accuracy of +-1 deg C in the ranging from -4 to 32 deg C. The response time for suddenly changing humidity was about 8 min.

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

Science.gov (United States)

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.

Protection of HCl dew point corrosion in municipal incinerators

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, S.; Tsuruta, T.; Maeda, N.

1976-12-01

HCl dew point corrosion is often observed on the components of municipal incinerators used for burning wastes which contain polyvinyl chloride. In order to solve the problem, the relation between concentrations of gaseous HCl and the corresponding dew points as well as concentrations of condensed HCl, was investigated. A series of HCl dipping tests for the materials concerned was performed and the dip test results were compared with in-plant tests. As a result it was concluded that HCl dew point corrosion can be reliably predicted from measurements of HCl concentrations in the water and in the gas and the partial pressure of the saturated steam at the dew point.

sarcome d'ewing

African Journals Online (AJOL)

7 mai 2012 ... Le sarcome d'Ewing est une tumeur osseuse rare corres- pondant à la ... Introduction : petrous Ewing sarcoma is exceptional. We report a ..... (15) Iriz A, Albayrak L, Eryilmaz A. Extraskeletal primary Ewing's sarcoma of the.

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

Science.gov (United States)

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.

Estimation of combustion flue gas acid dew point during heat recovery and efficiency gain

Energy Technology Data Exchange (ETDEWEB)

Bahadori, A. [Curtin University of Technology, Perth, WA (Australia)

2011-06-15

When cooling combustion flue gas for heat recovery and efficiency gain, the temperature must not be allowed to drop below the sulfur trioxide dew point. Below the SO{sub 3} dew point, very corrosive sulfuric acid forms and leads to operational hazards on metal surfaces. In the present work, simple-to-use predictive tool, which is easier than existing approaches, less complicated with fewer computations is formulated to arrive at an appropriate estimation of acid dew point during combustion flue gas cooling which depends on fuel type, sulfur content in fuel, and excess air levels. The resulting information can then be applied to estimate the acid dew point, for sulfur in various fuels up to 0.10 volume fraction in gas (0.10 mass fraction in liquid), excess air fractions up to 0.25, and elemental concentrations of carbon up to 3. The proposed predictive tool shows a very good agreement with the reported data wherein the average absolute deviation percent was found to be around 3.18%. This approach can be of immense practical value for engineers and scientists for a quick estimation of acid dew point during combustion flue gas cooling for heat recovery and efficiency gain for wide range of operating conditions without the necessity of any pilot plant setup and tedious experimental trials. In particular, process and combustion engineers would find the tool to be user friendly involving transparent calculations with no complex expressions for their applications.

An automatic dew-point hygrometer making use of β-ray backscattering and controlled at the constant amount of dew

International Nuclear Information System (INIS)

Matsumoto, Shigeaki; Kobayashi, Hisanobu

1988-01-01

A control system which consists of proportional and integral control to maintain the constant amount of dew was developed in this hygrometer. The dew points were measured within an accuracy of ±1 deg C in the ranging from -4 to 32 deg C. The response time for suddenly changing humidity was about 8 min. (author)

An automatic dew-point hygrometer making use of beta-ray backscattering

International Nuclear Information System (INIS)

Matsumoto, Sigeaki; Kobayashi, Hisanobu

1981-01-01

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 0 C to 60 0 C in the atmospheric temperature of 0 0 C to 60 0 C, that was the relative humidity of 12% to 100%, and the accuracy of the measurement was +-1 0 C. (author)

Study on dew point evaporative cooling system with counter-flow configuration

KAUST Repository

Lin, J.

2015-12-18

Dew point evaporative cooling has great potential as a disruptive process for sensible cooling of air below its entering wet bulb temperature. This paper presents an improved mathematical model for a single-stage dew point evaporative cooler in a counter-flow configuration. Longitudinal heat conduction and mass diffusion of the air streams, channel plate and water film, as well as the temperature difference between the plate and water film, are accounted for in the model. Predictions of the product air temperature are validated using three sets of experimental data within a discrepancy of 4%. The cooler’s heat and mass transfer process is analyzed in terms of its cooling capacity intensity, water evaporation intensity, and overall heat transfer coefficient along the channel. Parametric studies are conducted at different geometric and operating conditions. For the conditions evaluated, the study reveals that (1) the saturation point of the working air occurs at a fixed point regardless of the inlet air conditions, and it is mainly influenced by the working air ratio and channel height; (2) the intensity of the water evaporation approaches a minimum at 0.2 to 0.3m from the entrance; (3) the wet channel can be separated into two zones, and the overall heat transfer coefficient is above 100W/(m2·K) after the temperature of water film becomes higher than the working air temperature.

Multiobjective optimization in Gene Expression Programming for Dew Point

OpenAIRE

Shroff, Siddharth; Dabhi, Vipul

2013-01-01

The processes occurring in climatic change evolution and their variations play a major role in environmental engineering. Different techniques are used to model the relationship between temperatures, dew point and relative humidity. Gene expression programming is capable of modelling complex realities with great accuracy, allowing, at the same time, the extraction of knowledge from the evolved models compared to other learning algorithms. This research aims to use Gene Expression Programming ...

Analysis of points of dew and contents of humidity of gassy mixtures N2-H2 O and CH4 H2 O

International Nuclear Information System (INIS)

Bedoya M, D; Muller, C; Oellrich, L R

1995-01-01

The actual knowledge of the exact water content in saturated gas mixtures still is incomplete, especially in the high pressure and low temperature region. Hence, dew point measurements with nitrogen - water and methane-water mixtures were performed; at pressures of 3 and 6 MPa and temperatures from 258 K to 288 K. The dew points were determined with the dew point mirror method and the water content by means of the Karl-Fischer-titration. The experimental values were compared to correlations from the literature. The approach by Sharma-Campbell resulted in the best description of the system nitrogen - water. For temperatures below 273 K the assumption of ideal behavior proved to be sufficient for the system methane-water, whereas for temperatures above 273 K calculations with the two-parameter corresponding states principle in combination with a fugacity correction turned out to be the best

Measurements to determine the sulfuric acid dew point and the SO sub 3 concentration in flue gas of power plant vessels. Messungen zur Bestimmung des Saeuretaupunktes und der SO sub 3 -Konzentration im Rauchgas von Kraftwerkskesseln

Energy Technology Data Exchange (ETDEWEB)

Derichs, W.; Menden, W. (RWE Energie AG, Bergheim (Germany)); Ebel, P.K. (Apparatebau Hundsbach GmbH, Baden-Baden (Germany))

1990-01-01

Among the customary methods of dew point determination, the technique of recording the increase in conductivity between two electrodes at the moment of acid condensing onto them, and measuring at the same time the temperature of the sensor, is appropriate to determine the sulfuric acid dew point in dust-laden flue gas. By means of the sensitivity of a newly developed sensor, the accuracy of the measurement method could be improved to such an extent that also low acid dew points and rapid changes can be recorded reliably. Measurements have shown that the acid dew point primarily depends on the SO{sub 3} content which is substantially determined by the sulfur content of the fuel and the type of flue gas ducts. Further influential quantities include flue gas humidity, air surplus, other gaseous flue gas components such as HCl and HF, as well as the quantity, composition and temperature-dependent adsorption capability of the flue dusts. (orig./BBR).

Feasibility study of a novel dew point air conditioning system for China building application

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xudong; Yang, Shuang; Duan, Zhiyin; Riffat, Saffa B. [School of the Built Environment, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

2009-09-15

The paper investigated the feasibility of a novel dew point evaporative cooling for air conditioning of buildings in China regions. The issues involved include analyses of China weather conditions, investigation of availability of water for dew point cooling, and assessment of cooling capacity of the system within various regions of China. It is concluded that the dew point system is suitable for most regions of China, particularly northern and west regions of China where the climate is hot and dry during the summer season. It is less suitable for Guangzhou and Shanghai where climates are hot and humid. However, an air pre-treatment process involving a silica-gel dehumidification will enable the technology to be used for these humid areas. Lower humidity results in a higher difference between the dry bulb and dew point of the air, which benefits the system in terms of enhancing its cooling performance. Tap water has adequate temperature to feed the system for cooling and its consumption rate is in the range 2.6-3 litres per kWh cooling output. The cooling output of the system ranges from 1.1 to 4.3 W per m{sup 3}/h air flow rate in China, depending on the region where the system applies. For a unit with 2 kW of cooling output, the required air volume flow rate varies with its application location and is in the range 570-1800 m{sup 3}/h. For a 50 m{sup 2} building with 60 W/m{sup 2} cooling load, if the system operates at working hours, i.e., 09:00 to 17:00 h, its daily water consumption would be in the range of 60-70 litres. Compared with mild or humid climates, the dry and hot climates need less air volume flow rate and less water. (author)

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

Science.gov (United States)

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.

Increase in the boiler's performance in terms of the acid dew point temperature: Environmental advantages of replacing fuels

Energy Technology Data Exchange (ETDEWEB)

Blanco, J.M.; Pena, F. [Dpto. Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieria, Universidad del Pais Vasco/E.H.U., Alameda de Urquijo s/n (48013) Bilbao (Spain)

2008-05-15

The aim of air pre-heaters is to raise the temperature of the combustion air in boilers, using heat recovered from the power plant combustion gases. On the one hand, this paper compares the effects of the acid dew point temperature (ADT) on pre-heaters in a reference thermal power plant for two types of fuel, ''fuel No. 2'' and ''low sulphur fuel'' respectively and on the other hand, it shows how a changeover to this latter fuel would increase the useful lifetime of this equipment, reducing this way cost of maintenance due to the considerable decrease in the area exposed to ADT with the subsequent increase in the boiler's performance. (author)

Conditions for lowering the flue gas temperature; Foerutsaettning foer saenkning av roekgastemperatur

Energy Technology Data Exchange (ETDEWEB)

Nordling, Magnus

2012-02-15

In heat and power production, the efficiency of the power plant increases the larger share of heat from the flue gas that is converted to power. However, this also implies that the temperature of the heat exchanging surfaces is lowered. If the temperature is lowered to a temperature below the dew point of the flue gas, this would result in condensation of the gas, which in turn elevates the risk of serious corrosion attack on the surfaces where condensation occurs. Thus, it is important to determine the dew point temperature. One way of determining the dew point temperature is to use data on composition of the fuel together with operation parameters of the plant, thus calculating the dew point temperature. However, this calculation of the dew point is not so reliable, especially if hygroscopic salts are present. Therefore, for safety reasons, the temperature of the flue gas is kept well above the dew point temperature. This results in lowered over-all efficiency of the plant. It could also be expected that for a certain plant, some construction materials under certain operation conditions would have corrosion characteristics that may allow condensation on the surface without severe and unpredictable corrosion attack. However, by only using operation parameters and fuel composition, it is even harder to predict the composition of the condensate at different operation temperatures than to calculate the dew point temperature. If the dew point temperature was known with a greater certainty, the temperature of the flue gas could be kept lower, just above the estimated value of the dew point, without any increased risk for condensation. If, in addition, also the resulting composition of the condensate at different temperatures below the dew point is known, it can be predicted if the construction materials of the flue gas channel were compatible with the formed condensate. If they are compatible, the flue gas temperature can be further lowered from the dew point

Pipeline drying using dehumidified air with low dew point temperature

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Syed Younus; Gandhidasan, P.; Al-Farayedhi, A.A. [King Fahd Univ. of Petroleum and Minerals, Mechanical Engineering Dept., Dhahran (Saudi Arabia)

1998-05-01

The presence of humidity may be detrimental to the operation of pipelines transporting natural gas or other petroleum products. In particular conditions water solidifies or reacts chemically with hydrocarbons, forming hydrates. Such crystalline substances may cause obstruction of the lines and damage the equipment of the relevant facilities. A procedure for predicting the performance of drying a pipeline using dehumidified air with a low dew point is described in this paper. The mathematical model estimates the time required for the complete removal of moisture in the pipeline for the given operating conditions with simplified assumptions. The governing equations are solved analytically as well as numerically and the results are briefly discussed in the paper. (Author)

Dew Measurements along a Longitudinal Sand Dune Transect

NARCIS (Netherlands)

Jacobs, A.F.G.; Heusinkveld, B.G.; Berkowicz, S.

2000-01-01

In a desert environment dew can serve as an important source of moisture for plants, biological crusts, insects and small animals. A measurement programme was carried out within a sand dune belt situated in the northwestern Negev desert, Israel, to measure daily amounts of dew deposition as well as

Experimental study on dew point corrosion characteristics of the heating surface in a 65 t/h biomass-fired circulating fluidized bed boiler

International Nuclear Information System (INIS)

Wang, Yungang; Ma, Haidong; Liang, Zhiyuan; Chen, Heng; Zhao, Qinxin; Jin, Xin

2016-01-01

Highlights: • Dew point corrosion and ash deposit tests in a biomass-fired boiler were performed. • The XRD, XRF and SEM methods were used to analyze corrosion samples. • The deposits were made up of ash deposit layer, coupling layer and corrosion layer. • The metal matrix simultaneously confronted chlorine corrosion and oxygen corrosion. - Abstract: The dew point corrosion characteristics of the heating surface in a 65 t/h biomass-fired circulating fluidized bed (CFB) boiler were experimentally studied. The cross-sectional morphology and composition of the ash deposition were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray fluorescence spectrum (XRF), respectively. The results showed that the test tube surface was covered by ash deposit layer, coupling layer and corrosion layer. The ash deposit layer and the coupling layer were prone to spall off together. The coupling layer consists of partial ash and corrosion products. The corrosion layer was mainly composed of chlorides (FeCl_3, FeCl_2, and FeOCl) and oxides (FeOOH, Fe_2O_3). With the increase of the tube wall temperature, the corrosion depth decreased dramatically and the dew point corrosion was alleviated efficiently. The metal matrix simultaneously suffered from chlorine corrosion and oxygen corrosion. As the tube wall temperature was above water dew point, the main corrosion mode was oxygen corrosion. As the tube wall temperature was below water dew point, the main corrosion mode was chlorine corrosion.

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

Science.gov (United States)

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.

On dew and micrometeorology in an arid coastal ecosystem

NARCIS (Netherlands)

Heusinkveld, B.G.

2008-01-01

This study investigated intriguing aspects of dew within a sandy arid ecosystem situated in the NW Negev desert, Israel. The goal was to quantify dew formation and evaporation processes through sensor design, field measurements and modelling. To do this, two new sensors were developed. The first

New methods of subcooled water recognition in dew point hygrometers

Science.gov (United States)

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.

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

Energy Technology Data Exchange (ETDEWEB)

Wasterlain, S.; Hissel, D. [FC LAB, Techn' Hom, rue Thierry Mieg, 90010 Belfort Cedex (France); FEMTO-ST (UMR CNRS 6174), ENISYS Department, University of Franche-Comte, Techn' Hom, rue Thierry Mieg, 90010 Belfort Cedex (France); Candusso, D.; Harel, F. [FC LAB, Techn' Hom, rue Thierry Mieg, 90010 Belfort Cedex (France); INRETS, The French National Institute for Transport and Safety Research, Techn' Hom, rue Thierry Mieg, 90010 Belfort Cedex (France); Bergman, P.; Menard, P.; Anwar, M. [University of Connecticut, Connecticut Global Fuel Cell Center Department of Electrical and Computer Engineering, 44 Weaver Road, Unit 5233, Storrs, CT 06269-5233 (United States)

2010-02-15

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. (author)

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

Science.gov (United States)

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.

A comparative study of compression-expansion type dehumidification systems to achieve low dew point air

International Nuclear Information System (INIS)

Moon, Choon; Bansal, Pradeep

2009-01-01

This paper presents a theoretical feasibility study of three dehumidification systems to achieve air with dew points down to (-) 40 deg. C. The systems consist of compressors, heat exchangers, expanders and heaters. A thermodynamic model has been developed of the systems to study the effect of the compressor, expander, and heat recovery heat exchanger efficiency as a function of pressure ratio, net required work, quantity of condensed moisture, and system outlet dew point temperature. The analysis has revealed that the selection of a heat recovery heat exchanger is critical for an efficient dehumidification system, where compressor efficiency has the dominant effect on power consumption.

Dew water effects on leaf water using a stable isotope approach

Science.gov (United States)

Kim, K.; Lee, X.

2009-12-01

The presence of dew is a common meteorological phenomenon in field conditions and takes into account for significant portion of hydrologic processes in terrestrial ecosystems. The isotope composition of leaf water plays an important role in the isotopic water and carbon fluxes between terrestrial plants and the atmosphere. However, the consequence of dew formation in the plant-atmosphere relations has been ignored in many studies. The objective of this study is to improve our understanding of environmental and biological controls on the leaf water in equilibrium with dew water through laboratory experiments. Five species of plants (soybean, corn, sorghum, wheat, cotton) were grown hydroponically with water of a known isotopic content in a greenhouse. On the day of the experiment, they were first moved to ambient environment in full sunlight for at least 6 hr and then into a dark container inside the lab for up to 48 hr in which water vapor isotope ratios, temperature, and humidity were controlled. This arrangement created a step change in the forcing on the plant isotopic exchange. Leaves were sampled prior to the transfer to the dark container and 6 more times every 4 - 12 hr over the experiment. Humidity inside the container was saturated to mimic dew events in field conditions. Water from the leaf samples was extracted by a vacuum line and was analyzed for both δD and δ18O. The dataset will allow us to evaluate leaf water isotopic theories by exploring the transitions of the isotopic ratio of leaf water in response to the step change. Specifically, we are interested in whether the stomatal opening is an effective pathway for gaseous exchange in total darkness and how the transitional behaviors of the isotopic ratio of leaf water differ between the C3 and C4 photosynthesis pathways.

Technical aspects of acid dew point measurement in furnace exhaust. Messtechnik fuer die Saeuretaupunktmessung in Feuerungsabgasen

Energy Technology Data Exchange (ETDEWEB)

Struschka, M.; Baumbach, G.

1986-01-01

SO/sub 3/ formation in flue gases and the effect of furnace parameters, furnace type and design on the efficiency of SO/sub 2/ conversion were investigated in a detailed bibliographic study. Phase equilibrium data for the binary system H/sub 2/SO/sub 4//H/sub 2/O and equations for calculating the acid dew point are presented, and the available wet chemical methods for SO/sub 3/ concentration measurements in flue gases are reviewed. The SM1 acid dew point measuring instrument availabe at the authors' institute was modified by installing a new measuring probe, an external thermoelement intensifier, and a new PD control element for temperature control in the measuring surfaces. Acid dew point measurements were carried out in two different furnaces, i.e. a domestic boiler for light fuel oil and an industrial furnace fuelled with heavy oil at the Stuttgart University heat- and power plant. The measurements are compared with data from relevant publications. (orig./RB) With 80 figs., 7 tabs.

Evaluation of the physical dew point in the economizer of a combined cycle burning natural gas

Energy Technology Data Exchange (ETDEWEB)

Pena, F.; Blanco, J.M. [Universidad del Pais Vasco/E.H.U. Alameda de Urquijo s/n, Bilbao (Spain). Dpto. Maquinas y Motores Termicos, Escuela Sup. de Ingenieria

2007-08-15

Natural gas contents a considerable percentage of hydrogen, so is obvious to expect an amount of water vapour in its combustion exhaust gases, which would raise the dew point temperature. That means a higher speed of corrosion over the whole exposed physical area, which could represent a serious risk of breakdown, especially in pressurized hot-water equipments. In this work, a new methodology for determining the physical dew point inside a economizer depending on the fuel type burned (in this case is natural gas) has been developed. The calculation of the total amount of condensed water has also been carried out as well as the localization of the area where this condensation occurs. Acid dew point has not been taken into account here although exhaust gases are acidic, due mainly to the low sulphur content which is almost undetectable when burning natural gas, but it will be performed in a later study coming soon. (author)

Feedback dew-point sensor utilizing optimally cut plastic optical fibres

Science.gov (United States)

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.

Dew point temperature affects ascospore release of allergenic genus Leptosphaeria

Science.gov (United States)

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

Science.gov (United States)

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).

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

Science.gov (United States)

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.

Initial response of an automatic dew-point hygrometer using [beta]-ray backscattering

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Shigeaki (Saitama Univ., Urawa (Japan). Faculty of Engineering)

1992-05-01

This paper describes the initial response of an automatic dew-point hygrometer using [beta]-ray backscattering. The response time after starting of measurement was evaluated in which the dew point measured with the hygrometer reached a value of 90 percent of the correct dew point in its response. Theoretical calculation was made by means of the loop transfer function of a control system employed in the hygrometer. The response times ranged from 1.7 min to 16 min corresponding to the dew point of 47.5degC and -6degC, respectively, and agreed well with experimental ones. (author).

Development of a neural fuzzy system for advanced prediction of dew point pressure in gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Nowroozi, Saeed; Hashemipour, Hasan; Schaffie, Mahin [Department of Chemical Engineering, Shahid Bahonar University of Kerman (Iran); ERC, Shahid Bahonar University of Kerman (Iran); Ranjbar, Mohammad [Department of Mining Engineering, Shahid Bahonar University of Kerman (Iran); ERC, Shahid Bahonar University of Kerman (Iran)

2009-03-15

Dew point pressure is one of the most critical quantities for characterizing a gas condensate reservoir. So, accurate determination of this property has been the main challenge in reservoir development and management. The experimental determination of dew point pressure in PVT cell is often difficult especially in case of lean retrograde gas condensate. Empirical correlations and some equations of state can be used to calculate reservoir fluid properties. Empirical correlations do not have ability to reliable duplicate the temperature behavior of constant composition fluids. Equations of state have convergence problem and need to be tuned against some experimental data. Complexity, non-linearity and vagueness are some reservoir parameter characteristic which can be propagated simply by intelligent system. With the advantage of fuzzy sets in knowledge representation and the high capacity of neural nets (NNs) in learning knowledge expressed in data, in this paper a neural fuzzy system(NFS) is proposed to predict dew point pressure of gas condensate reservoir. The model was developed using 110 measurements of dew point pressure. The performance of the model is compared against performance of some of the most accurate and general correlations for dew point pressure calculation. From the results of this study, it can be pointed out that this novel method is more accurate and reliable with the mean square error of 0.058%, 0.074% and 0.044% for training, validation and test processes, respectively. (author)

Calculating the flue gas dew point for raw brown coal fired steam generators

Energy Technology Data Exchange (ETDEWEB)

Schinkel, W.

1977-01-01

The paper analyzes parameters influencing the sulfuric acid dew point in flue gas of steam generators. Sulfur content and alkaline earths content in the fuel air ratio during combustion, fly ash content in the flue gas (which absorbs sulfur dioxide and sulfur trioxide) and combustion conditions in steam generators are relevant parameters in the combustion process. A thermodynamic and reaction kinetic calculation of the sulfuric acid dew point is, however, not yet possible. A statistical evaluation of dew point measurements in steam generators is, therefore, employed. Various diagrams show results of dew point measurements carried out at generators with steam capacities ranging from 40 to 660 t/h, which demonstrate relations of these parameters to flue gas dew points, in particular the relative sulfur content (sulfur content in the raw brown coal compared to coal ash content and alkaline earths content). A function is derived for the conversion of fuel sulfur to sulfur trioxide. A diagram presents the relation of the flue gas dew point to partial pressures of sulfuric acid and steam. Direct calculation of the flue gas dew point was achieved by the proposed method. It is applied in steam generator design. (17 refs.)

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

Science.gov (United States)

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

Is KCl(g) corrosive at temperatures above its dew point? Influence of KCl(g) on initial stages of the high temperature corrosion of 11% Cr steel at 600 C

Energy Technology Data Exchange (ETDEWEB)

Segerdahl, K.; Pettersson, J.; Svensson, J.E.; Johansson, L.G. [Dept. of Environmental Inorganic Chemistry, High Temperature Corrosion Centre, Chalmers Univ. of Technology, Goeteborg (Sweden)

2004-07-01

The influence of gaseous KCl on the high temperature oxidation of CrMoV11 1 (X20) steel at 600 C is reported. The sample temperature was above the dew point of KCl, the partial pressure of KCl being about 5ppm. The samples were investigated by a number of surface analytical techniques including grazing angle XRD, SEM/EDX, and SAM. CrMoV11 1 steel shows protective behaviour in clean dry O{sub 2} and O{sub 2}/H{sub 2}O environment because of the formation of a chromium-rich oxide ({alpha}-(Fe,Cr){sub 2}O{sub 3}). It is often considered that alkali salts accelerate the corrosion of steel only when present on the surface in solid or liquid form. In contrast, the present result shows that gaseous KCl is very corrosive, also in the absence of condensation. KCl(g) reacts with chromium in the scale, forming K{sub 2}CrO{sub 4}(s). This depletes the protective oxide in chromium and leads to the formation of non-protective hematite, Fe{sub 2}O{sub 3}. (orig.)

Applicability of a desiccant dew-point cooling system independent of external water sources

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

2015-01-01

The applicability of a technical solution for making desiccant cooling systems independent of external water sources is investigated. Water is produced by condensing the desorbed water vapour in a closed regeneration circuit. Desorbed water recovery is applied to a desiccant dew-point cooling...... system, which includes a desiccant wheel and a dew point cooler. The system is simulated during the summer period in the Mediterranean climate of Rome and it results completely independent of external water sources. The seasonal thermal COP drops 8% in comparison to the open regeneration circuit solution...

Automated and continuously operating acid dew point measuring instrument for flue gases

Energy Technology Data Exchange (ETDEWEB)

Reckmann, D.; Naundorf, G.

1986-06-01

Design and operation is explained for a sulfuric acid dew point indicator for continuous flue gas temperature control. The indicator operated successfully in trial tests over several years with brown coal, gas and oil combustion in a measurement range of 60 to 180 C. The design is regarded as uncomplicated and easy to manufacture. Its operating principle is based on electric conductivity measurement on a surface on which sulfuric acid vapor has condensed. A ring electrode and a PtRh/Pt thermal element as central electrode are employed. A scheme of the equipment design is provided. Accuracy of the indicator was compared to manual dew point sondes manufactured by Degussa and showed a maximum deviation of 5 C. Manual cleaning after a number of weeks of operation is required. Fly ash with a high lime content increases dust buildup and requires more frequent cleaning cycles.

Dew point of combustion products of coal from the Berezovo deposit

Energy Technology Data Exchange (ETDEWEB)

Petrov, V.A. (UralVTI (USSR))

1990-11-01

Evaluates properties of brown coal from the Berezovo deposit, Kansk-Achinsk basin, and properties of its combustion products. Coal properties are the following: sulfur content from 0.26 to 0.49%, ash content from 3.49 to 6.58%, moisture content from 31.6 to 36.9%, calorific value from 14,200 to 15,840 kJ/kg. Dew point of the combustion products amounts to 51 C and is equal to that of water vapor present in flue gases. Changing boiler output does not influence dew point. Increase in the excess air coefficient from 1.2 to 1.4 results in an increase in dew point by 2-3 K; further increase in air excess coefficient to 1.64 causes a decline in dew point by 3-4 K. 2 refs.

The dew point response of the annulus gas system of Bruce NGS A

International Nuclear Information System (INIS)

Kenchington, J.; Ellis, P.J.; Meranda, D.

1983-01-01

The dew point response of the Annulus Gas System in Bruce A, Units 1 and 2 has been modelled in order to alert the operator of the presence of heavy water and to estimate the leak rate into the annulus. The computer model can be easily adapted to determine the Annulus Gas System dew point response in any station. It models the complex arrangement of the system and the transportation of moisture through the annuli by a combination of plug flow and mixing of CO 2 and D 2 O vapor. It predicts the response of the dew point monitor for a range of specified leak rates and positions of a leaking channel in a string of channels. This model has been used to calculate the variation of dew point and rate of change of dew point with respect to time (t). It shows that there is a maximum in the rate of dew point change (dT/dt) with respect to the corresponding dew point (T). This maximum is unique for a given leak rate and channel position. It is independent of the starting time for the leak. The computer programme has been verified by an analytical solution for the model

Dew as an Adaptation Measure to Meet Agricultural and Reforestation Water Demand in a Changing Climate

Science.gov (United States)

Tomaszkiewicz, Marlene; Abou Najm, Majdi; Alameddine, Ibrahim; El Fadel, Mutasem

2014-05-01

Dew harvesting, believed to be an ancient technique, has recently re-emerged as a viable and sustainable water resource. Nightly yields are relatively low, yet non-negligible, and dew events occur more frequently than rainfall promoting its effectiveness, particularly in arid and semi-arid regions. In this study, we demonstrate how dew can be harvested and subsequently used for small-scale irrigation to meet agricultural and reforestation water demand. Polyethylene dew harvesting systems were constructed and placed in the field. Dew was harvested as a result of the radiative cooling during the night, thus allowing dew formation under conditions of high humidity. Condensed dew formed upon the planar surface was collected by gravity. Water demand for selected crops and trees within a pilot study area (Lebanon) was estimated using a deficit irrigation model. Simulations of water demand requirements of various plants and surfaces were performed and compared to dew volumes to assess the ability of the system to meet all or in part the plant water demands across seasons. Data from the polyethylene low-cost dew condensers have shown that within the pilot study, average nightly dew yields were 0.1 L m-2 of condensing surface with a maximum yield of 0.4 L m-2. Dew events occurred generally more frequently than precipitation events, with an estimated 40% of nights producing dew condensate. This translates to 50 mm of equivalent rainfall on average (during dew nights), with a maximum of 200 mm in one night, if one assumes using drip irrigation over a seedling within a 20 cm2 area. Using a simple deficit irrigation model, it was demonstrated that crops such as the tomato plant, which typically has a growing season during the dry summer, can potentially be irrigated solely by dew, thus eliminating the need for traditional irrigation sources. Similarly, young tree seedlings, such as the cedar tree, can depend upon dew as a primary water resource. Moreover, based on similar

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

Science.gov (United States)

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.

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.

Science.gov (United States)

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.

Chemical Characterization of Dew Water Collected in Different Geographic Regions of Poland

Directory of Open Access Journals (Sweden)

Jacek Namieśnik

2008-06-01

Full Text Available The results of a dew monitoring program performed in Poland with the aim to outline the chemical composition of dew water in meteorological context are presented. Dew samples were collected from eight measurement stations from August 2004 to November 2006. Taking into account the type of land use and characteristics of pollutant emission, sampling sites were divided into the following categories: rural, coastal urban and inland urban stations. Selected anions and cations as well as formaldehyde and sum of phenols were determined. The average TIC (Total Inorganic Ionic Content values in dew samples ranged from 0.83 to 3.93 between individual stations with 10.9 meq/L as the highest daily value of TIC measured. The average TIC values observed in dew at all stations were at a similar level (2.46 meq/L when compared with hoarfrost (2.86 meq/L. However, these values were much higher in comparison with other kinds of atmospheric water like precipitation (wet only; 0.37 meq/L or fog/cloud (1.01 meq/L. The pH values of dew water ranged from 5.22 to 7.35 for urban coastal stations, from 5.67 to 8.02 for urban inland stations and from 4.16 to 8.76 for dew samples collected in the rural area. HCHO was found in 97 % of dew samples, with concentrations ranging from 0.010 to 5.40 meq/L. Excluding stations near the seashore, where the contribution of Na+ and Cl- increased, the most important ions were sulphates. A very low contribution of NO3- and noticeable increase of Ca2+ which were not observed in the case of precipitation and fog water, were typical in all stations. The contribution of ammonium ion was two times higher at rural stations as a result of agricultural ammonia emissions. The strongest correlations were noticed between the sum of acidifying anions SO42- + NO3- and Ca2+ ion for all urban and rural stations. A very strong correlation was also observed for Na+ and Cl- ions in urban coastal stations, as a natural consequence of the location of these

Application of a two-sinker densimeter for phase-equilibrium measurements: A new technique for the detection of dew points and measurements on the (methane + propane) system

International Nuclear Information System (INIS)

McLinden, Mark O.; Richter, Markus

2016-01-01

Highlights: • A new technique for detecting dew points in fluid mixtures is described. • The method makes use of a two-sinker densimeter. • The technique is based on a quantitative measurement of sample mass adsorbed onto the surface of the densimeter sinkers. • The dew-point density and dew-point pressure are determined with low uncertainty. • The method is applied to the (methane + propane) system and compared to traditional methods. - Abstract: We explore a novel method for determining the dew-point density and dew-point pressure of fluid mixtures and compare it to traditional methods. The (p, ρ, T, x) behavior of three (methane + propane) mixtures was investigated with a two-sinker magnetic suspension densimeter over the temperature range of (248.15–293.15) K; the measurements extended from low pressures into the two-phase region. The compositions of the gravimetrically prepared mixtures were (0.74977, 0.50688, and 0.26579) mole fraction methane. We analyzed isothermal data by: (1) a “traditional” analysis of the intersection of a virial fit of the (p vs. ρ) data in the single-phase region with a linear fit of the data in the two-phase region; and (2) an analysis of the adsorbed mass on the sinker surfaces. We compared these to a traditional isochoric experiment. We conclude that the “adsorbed mass” analysis of an isothermal experiment provides an accurate determination of the dew-point temperature, pressure, and density. However, a two-sinker densimeter is required.

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

Science.gov (United States)

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).

Memory persistency and nonlinearity in daily mean dew point across India

Science.gov (United States)

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.

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

Science.gov (United States)

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%.

Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

Energy Technology Data Exchange (ETDEWEB)

Leopoldo, P R [Faculdade de Ciencias Medicas e Biologicas de Botucatu (Brazil); Salati, E; Matsui, E [Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

1975-12-01

The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs.

Determination of dew absorption by coffee plant through deuterium concentrations in leaf water

International Nuclear Information System (INIS)

Leopoldo, P.R.; Salati, E.; Matsui, E.

1975-01-01

The effect of dew falling on leaves on the water metabolism of the coffee plant (Coffea arabica) is examined. The use of natural stable isotopes variations in plant physiological studies is demonstrated. Water extracted from leaf samples is analysed by mass spectrometry. Analyses of deuterium concentrations in water extracted from plant leaves, dew and nutrient solutions are made. Determination of changes in deuterium concentration in the water of leaves from plants exposed to dew, compared with leaves not exposed to dew, is carried out. Results show that during daytime there is an enrichment in deuterium in water contained in the leaves, while at night the opposite occurs [pt

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

Science.gov (United States)

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).

Effect of artificially-generated wind on removing guttation and dew ...

African Journals Online (AJOL)

DynabookSS

2015-03-25

Mar 25, 2015 ... wind on the formation and removal of guttation and dew droplets on rice leaves. ... Wind is thought to reduce the number of spores attached to rice plant and to promote removal of dew droplets on the leaves. Thus, the penetration of blast into ..... and the application for forecasting method of the rice blast.

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

Science.gov (United States)

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.

Using dew points to estimate savings during a planned cooling shutdown

Science.gov (United States)

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.

Numerical study of a novel dew point evaporative cooling system

Energy Technology Data Exchange (ETDEWEB)

Riangvilaikul, B.; Kumar, S. [Energy Field of Study, School of Environment, Resources and Development, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120 (Thailand)

2010-11-15

Dew point evaporative cooling system is an alternative to vapor compression air conditioning system for sensible cooling of ventilation air. This paper presents the theoretical performance of a novel dew point evaporative cooling system operating under various inlet air conditions (covering dry, moderate and humid climate) and influence of major operating parameters (namely, velocity, system dimension and the ratio of working air to intake air). A model of the dew point evaporative cooling system has been developed to simulate the heat and mass transfer processes. The outlet air conditions and system effectiveness predicted by the model using numerical method for known inlet parameters have been validated with experimental findings and with recent literature. The model was used to optimize the system parameters and to investigate the system effectiveness operating under various inlet air conditions. (author)

Natural gas treatment: Simultaneous water and hydrocarbon-dew point-control

Energy Technology Data Exchange (ETDEWEB)

Schmidt, T. (Solvay Catalysts GmbH, Hannover (Germany)); Rennemann, D. (Solvay Catalysts GmbH, Hannover (Germany)); Schulz, T. (Solvay Catalysts GmbH, Hannover (Germany))

1993-10-01

Natural gas is a multicomponent mixture of hydrocarbons. The condensation behavior of such mixtures is different from single component systems. The so-called retrograde behavior leads to the observations that saturated vapor (dew point curve) and saturated liquid curve (bubble point curve) are not identical. Between both is a region of saturated phases which even can exist above the critical point. Following this behaviour it is possible that condensation might occur at pressure decrease or at temperature increase, respectively. This phenomenon is undesired in natural gas pipeline networks. Selective removal of higher hydrocarbons by the means of adsorption can change the phase behavior in such a way that condensation does not occur at temperatures and pressures specified for gas distribution. (orig.)

Large Dew water collectors in a village of S-Morocco (Idouasskssou)

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Bubble and Dew Point Calculations in Multicomponent and Multireactive Mixtures

OpenAIRE

Bonilla-Petriciolet, A.; Acosta-Martínez, A.; Bravo-Sánchez, U. I.; Segovia-Hernández, J. G.

2006-01-01

Bubble and dew point calculations are useful in chemical engineering and play an important role in the study of separation equipments for non-reactive and reactive mixtures. To the best of the authors’s knowledge, few methods have been proposed for these calculations in systems with several chemical reactions. The objective of this paper is to introduce new conditions for performing bubble and dew point calculations in reactive mixtures. We have developed these conditions based on the a...

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

Science.gov (United States)

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

Development of sulfuric acid dew point corrosion resistant stainless steel for smokestacks and its ducts. Entotsu endoyo tairyusan roten fushoku stainless ko no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Sato, E.; Matsuhashi, R.; Koseki, T. (Nippon Steel Corp., Tokyo (Japan)); Ebara, R.; Nakamoto, H. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan))

1993-05-20

A new corrosion resistant steel was developed as a metal system lining material to prevent sulfuric acid dew point corrosion in smokestacks and ducts. SO3 in stack gas turns to sulfuric acid as a result of reacting with coexistent moisture in non-steady conditions during boiler actuation and shutdown when smokestack walls have low temperatures. When sulfuric acid thus generated contacts with metallic materials at temperatures lower than the sulfuric acid dew point temperature, sulfuric acid dew point corrosion occurs. During boiler steady operation, localized corrosion develops at clearance between salt deposits and the metallic materials. In order to improve the corrosion resistance, Mo, Cu and N were added in a reasonable range of amount. Entire surface corrosion resistance and local corrosion resistance were experimented in aqueous solutions simulating the smokestack environments to derive relational formulas with steel compositions. The new corrosion resistant steel met the the entire surface and local corrosion resistance requirements and was found economical. Low torsional velocity tensile and U-bend tests proved the steel satisfying the stress corrosion resistance requirement. Semi-automatic CO2 welding and shielded are welding provided good workability with no cracking, and impact strength and corrosion resistance in joints equivalent to those in the base material. 3 refs., 4 figs., 4 tabs.

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

Science.gov (United States)

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.

Estimating dew formation in rice, using seasonally averaged diel patterns of weather variables

NARCIS (Netherlands)

Luo, W.; Goudriaan, J.

2004-01-01

If dew formation cannot be measured it has to be estimated. Available simulation models for estimating dew formation require hourly weather data as input. However, such data are not available for places without an automatic weather station. In such cases the diel pattern of weather variables might

Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method)

DEFF Research Database (Denmark)

Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf......Detection of Dew-Point by substantial Raman Band Frequency Jumps (A new Method). See poster at http://www.kemi.dtu.dk/~ajo/rolf/jumps.pdf...

Simultaneous measurements of formaldehyde and nitrous acid in dews and gas phase in the atmosphere of Santiago, Chile

Science.gov (United States)

Rubio, María A.; Lissi, Eduardo; Villena, Guillermo; Elshorbany, Y. F.; Kleffmann, Jörg; Kurtenbach, Ralf; Wiesen, Peter

2009-12-01

The amounts of formaldehyde and nitrous acid (HONO) in gas phase and dews of Santiago de Chile were simultaneously measured. Formaldehyde concentrations values in the liquid phase (dews) correlate fairly well with those in the gaseous phase and are even higher than those expected from gas-dew equilibrium. On the other hand, nitrite concentrations in dews were considerably smaller (ca. 15 times) than those expected from the gas-phase concentrations. This under-saturation is attributed to diffusion limitations due to the relatively large HONO solubility. In agreement with this, under-saturation increases with the rate of dew formation and the pH of the collected waters, factors that should increase the rate of gas to liquid HONO transfer required to reach equilibrium.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Accurate prediction of the dew points of acidic combustion gases by using an artificial neural network model

International Nuclear Information System (INIS)

ZareNezhad, Bahman; Aminian, Ali

2011-01-01

This paper presents a new approach based on using an artificial neural network (ANN) model for predicting the acid dew points of the combustion gases in process and power plants. The most important acidic combustion gases namely, SO 3 , SO 2 , NO 2 , HCl and HBr are considered in this investigation. Proposed Network is trained using the Levenberg-Marquardt back propagation algorithm and the hyperbolic tangent sigmoid activation function is applied to calculate the output values of the neurons of the hidden layer. According to the network's training, validation and testing results, a three layer neural network with nine neurons in the hidden layer is selected as the best architecture for accurate prediction of the acidic combustion gases dew points over wide ranges of acid and moisture concentrations. The proposed neural network model can have significant application in predicting the condensation temperatures of different acid gases to mitigate the corrosion problems in stacks, pollution control devices and energy recovery systems.

Investigation of a novel dew point indirect evaporative air conditioning system for buildings

OpenAIRE

Duan, Zhiyin

2011-01-01

This study aims to improve the performance of existing indirect evaporative coolers. A new dew point indirect evaporative cooler with counter-current heat/mass exchanger was developed in this research by optimal design, material selection, numerical simulation, experimental investigations and economic, environmental, regional acceptance analysis. A new dew point heat/mass exchanger using a counter-current flow pattern was designed by numerical simulation in terms of material, structure, g...

Fort St. Vrain high temperature gas-cooled reactor. Pt. 12. The dew point moisture monitor testing program

Energy Technology Data Exchange (ETDEWEB)

Olson, H.G. (Colorado State Univ., Fort Collins (USA). Dept. of Mechanical Engineering); Brey, H.L. (Public Service Co. of Colorado, Denver (USA)); Swart, F.E. (Gas-Cooled Reactor Associates, La Jolla, CA (USA)); Forbis, J.M. (Storage Technology Corp., Louisville, CO (USA))

1982-09-01

Moisture ingress into the core volume could cause damaging reactions with the moderator-reflector graphite and burnable poison, therefore a dew point moisture monitoring system has been developed with the basic design criteria that a plant protective system trip is signaled after the system detects high primary coolant helium moisture levels and that the system is able to correctly identify which of two steam generator loops is leaking. Modifications to the sample supplies to the monitors were necessary to reduce the system's unsatisfactory response time at lower reactor power levels.

Dew point measurement technique utilizing fiber cut reflection

Science.gov (United States)

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.

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

Science.gov (United States)

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.

High Response Dew Point Measurement System for a Supersonic Wind Tunnel

Science.gov (United States)

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.

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

Science.gov (United States)

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

Fuzzy logic prediction of dew point pressure of selected Iranian gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Nowroozi, Saeed [Shahid Bahonar Univ. of Kerman (Iran); Iranian Offshore Oil Company (I.O.O.C.) (Iran); Ranjbar, Mohammad; Hashemipour, Hassan; Schaffie, Mahin [Shahid Bahonar Univ. of Kerman (Iran)

2009-12-15

The experimental determination of dew point pressure in a window PVT cell is often difficult especially in the case of lean retrograde gas condensate. Besides all statistical, graphical and experimental methods, the fuzzy logic method can be useful and more reliable for estimation of reservoir properties. Fuzzy logic can overcome uncertainty existent in many reservoir properties. Complexity, non-linearity and vagueness are some reservoir parameter characteristics, which can be propagated simply by fuzzy logic. The fuzzy logic dew point pressure modeling system used in this study is a multi input single output (MISO) Mamdani system. The model was developed using experimentally constant volume depletion (CVD) measured samples of some Iranian fields. The performance of the model is compared against the performance of some of the most accurate and general correlations for dew point pressure calculation. Results show that this novel method is more accurate and reliable with an average absolute deviation of 1.33% and 2.68% for developing and checking, respectively. (orig.)

Determination of dew point in natural gas; Determinacion del punto de rocio en el gas natural

Energy Technology Data Exchange (ETDEWEB)

Avila Calzada, S.; Marco Martinez, G.; Montenegro Soto, S. [ENAGAS (Spain)

1995-07-01

The natural gas can contain water and heavy hydrocarbons very dangerous for the equipments and the pipes. This is the reason of the importance of dew point. The value of this dew point is fixed in the supply contract conditions. This article studies the different evaluation methods, pointing out the advantages and disadvantages (Author)

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

Energy Technology Data Exchange (ETDEWEB)

Broddefalk, Arvid [Development and Market Research, Cogent Power Ltd., P.O. Box 201, SE-735 23 Surahammar (Sweden)], E-mail: arvid.broddefalk@sura.se; Jenkins, Keith [Development and Market Research, Cogent Power Ltd., P.O. Box 201, SE-735 23 Surahammar (Sweden); Silk, Nick [Corus RD and T, Swinden Technology Centre, Moorgate Rotherham S60 3AR (United Kingdom); Lindenmo, Magnus [Development and Market Research, Cogent Power Ltd., P.O. Box 201, SE-735 23 Surahammar (Sweden)

2008-10-15

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 deg. 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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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).

TFOS DEWS II Tear Film Report.

Science.gov (United States)

Willcox, Mark D P; Argüeso, Pablo; Georgiev, Georgi A; Holopainen, Juha M; Laurie, Gordon W; Millar, Tom J; Papas, Eric B; Rolland, Jannick P; Schmidt, Tannin A; Stahl, Ulrike; Suarez, Tatiana; Subbaraman, Lakshman N; Uçakhan, Omür Ö; Jones, Lyndon

2017-07-01

The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership. Copyright © 2017 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Sales gas hydrocarbon dew point control with a refrigeration plant; Konditionierung des Kohlenwasserstofftaupunktes im Verkaufsgas mittels einer Kaelteanlage

Energy Technology Data Exchange (ETDEWEB)

Konieczny, J.; Scsepka, H. [OMV Aktiengesellschaft, Exploration and Production, Gaenserndorf (Austria)

2004-11-01

A new refrigeration plant was put on stream in the gas plant Aderklaa, Austria in the fall 2003. The quality criteria inherent to hydrocarbon dew point of the sales gas have already been accomplished. The contract (Allgemeinen Netzzugangsbedingungen) defines the hydrocarbon dew point at the value of 0 C with a pressure ranging 0-70 bar(g). Process facilities are a gas/gas-heat exchanger and a low-temperature-separator flanged to the chiller. A propane cycle produces the required cooling energy. The propane cycle consists of two propane compressors, one of them as back up, a condenser, an accumulator and an evaporator. About 50,000 m{sup 3} (V{sub n}) sales gas per hour are produced at a working pressure of 65 bar(g). Process gas coming from the sweetening plant Aderklaa I is lowered to a temperature of -14 C, where approx. 250 litres liquid hydrocarbons per hour are separated and saved. When the refrigeration plant was designed, attention was given to the operating costs to keep them low. This could be achieved by maximising surface area for heat transfer in the gas/gas-heat exchanger. After commissioning and start-up, full operability of the new plant was tested and documented. The pre-set project goals were accomplished, with respect to both the technical point of view and the economic aspects. (orig.)

Characterisation of a microwave re-entrant cavity resonator for phase-equilibrium measurements and new dew-point data for a (0.25 argon + 0.75 carbon dioxide) mixture

International Nuclear Information System (INIS)

Tsankova, Gergana; Richter, Markus; Madigan, Adele; Stanwix, Paul L.; May, Eric F.; Span, Roland

2016-01-01

Highlights: • A microwave reentrant cavity resonator was refurbished and extensively characterised. • Vacuum resonance frequencies and Q-factors were modelled and experimentally validated. • Whispering gallery-type modes first-time reported for present cavity geometry. • Dew points of a (0.2491 argon + 0.7509 carbon dioxide) mixture were measured. • Measurements were carried out from T = (252–280) K at pressures up to 6.9 MPa. - Abstract: An apparatus based on a microwave re-entrant cavity resonator, originally built for accurate measurements of the dielectric permittivity of natural gas mixtures, was refurbished and extensively characterised. This was done to enable the future investigation of phase equilibria and (p, ρ, T, x) behaviour of fluid mixtures utilizing the present experimental technique. Vacuum resonance frequencies and Q-factors of the resonator’s modes were modelled using both analytic and finite element methods, and found to compare well with experimental values. The finite element models helped to identify two whispering gallery-type modes not previously reported for such cavity geometries. The models also predict distributions of the electric and magnetic fields in the re-entrant cavity resonator useful for identifying regions in the cavity more sensitive to the presence of a liquid. Following the resonator’s characterisation, its ability to measure dew points was tested using a gravimetrically prepared (0.2501 argon + 0.7499 carbon dioxide) mixture over the temperature range from (252 to 280) K at pressures from (2.8 to 6.9) MPa. The combined expanded uncertainty with a level of confidence of approximately 95% (k = 2) in dew-point temperature and pressure ranged between (0.025 and 0.044) K and from (0.009 to 0.015) MPa, respectively. We compared the experimental dew-point pressures with the recently developed multi-parameter equation of state optimised for combustion gases (EOS-CG), showing relative deviations in the range of (0

Dew formation on the surface of biological soil crusts in central European sand ecosystems

Directory of Open Access Journals (Sweden)

T. Fischer

2012-11-01

Full Text Available Dew formation was investigated in three developmental stages of biological soil crusts (BSC, which were collected along a catena of an inland dune and in the initial substrate. The Penman equation, which was developed for saturated surfaces, was modified for unsaturated surfaces and used for prediction of dewfall rates. The levels of surface saturation required for this approach were predicted using the water retention functions and the thicknesses of the BSCs. During a first field campaign (2–3 August 2011, dewfall increased from 0.042 kg m⁻² for the initial sandy substrate to 0.058, 0.143 and 0.178 kg m⁻² for crusts 1 to 3, respectively. During a second field campaign (17–18 August 2011, where dew formation was recorded in 1.5 to 2.75-h intervals after installation at 21:30 CEST, dewfall increased from 0.011 kg m⁻² for the initial sandy substrate to 0.013, 0.028 and 0.055 kg m⁻² for crusts 1 to 3, respectively. Dewfall rates remained on low levels for the substrate and for crust 1, and decreased overnight for crusts 2 and 3 (with crust 3 > crust 2 > crust 1 throughout the campaign. Dew formation was well reflected by the model response. The suggested mechanism of dew formation involves a delay in water saturation in near-surface soil pores and extracellular polymeric substances (EPS where the crusts were thicker and where the water capacity was high, resulting in elevated vapor flux towards the surface. The results also indicate that the amount of dewfall was too low to saturate the BSCs and to observe water flow into deeper soil. Analysis of the soil water retention curves revealed that, despite the sandy mineral matrix, moist crusts clogged by swollen EPS pores exhibited a clay-like behavior. It is hypothesized that BSCs gain double benefit from suppressing their competitors by runoff generation and from improving their water supply by dew collection. Despite higher amounts of dew, the

Exploitation of humid air latent heat by means of solar assisted heat pumps operating below the dew point

International Nuclear Information System (INIS)

Scarpa, Federico; Tagliafico, Luca A.

2016-01-01

Highlights: • The opportunity of humid air latent heat exploitation by DX-SAHP is investigated. • A set of experimental tests confirms this opportunity and quantifies it as relevant. • A parametric analysis is performed, via simulation, to deepen the subject. • The energy gain is relevant during both night and daytime. - Abstract: Nowadays, the exploitation of environmental exergy resources for heating purposes (solar energy, convection heat transfer from ambient air, moist air humidity condensation) by means of properly designed heat pump systems is a possible opportunity. In particular, the use of direct expansion solar assisted heat pumps (DX-SAHP) is investigated in this study, when a bare external plate (the solar collector) is kept at temperatures lower than the dew point temperature of ambient air, so that condensation takes place on it. The potential of this technology is settled and an instrumented prototype of a small DX-SAHP system is used to verify the actual performance of the system, in terms of specific thermal energy delivered to the user, efficiency and regulation capabilities. Results clearly show that the contribution of the condensation is significant (20%–30% of the total harvested energy) overnight or in cloudy days with very low or no solar irradiation, and must be taken into account in a system model devoted to describe the DX-SAHP behavior. During daytime, the percentage gain decreases but is still consistent. By investigating along these lines, the heat due to condensation harvested by the collector is found to be a function of the dew-point temperature alone.

Miniaturised Optical Fibre Sensor for Dew Detection Inside Organ Pipes

Directory of Open Access Journals (Sweden)

Francesco Baldini

2008-01-01

Full Text Available A new optical sensor for the continuous monitoring of the dew formation inside organ pipes was designed. This aspect is particularly critical for the conservation of organs in unheated churches since the dew formation or the condensation on the pipe surfaces can contribute to many kinds of physical and chemical disruptive mechanisms. The working principle is based on the change in the reflectivity which is observed on the surface of the fibre tip, when a water layer is formed on its distal end. Intensity changes of the order of 35% were measured, following the formation of the water layer on the distal end of a 400/430 μm optical fibre. Long-term tests carried out placing the fibre tip inside the base of an in-house-made metallic foot of an organ pipe located in an external environment revealed the consistency of the proposed system.

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

Science.gov (United States)

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.

Reprises textuelles dans The Dew Breaker d’Edwidge Danticat Rewriting / Reprising in Edwidge Danticat’s The Dew Breaker

Directory of Open Access Journals (Sweden)

Corinne Duboin

2007-01-01

Full Text Available In her recent novel, The Dew Breaker (2004, Haitian-American writer Edwidge Danticat weaves together the lives of her bruised Haitian characters and their torturer, a former Tonton Macoute, all in exile in the US. Seven of the nine chapters were previously published as separate short stories and have been rearranged to form a novel. The reader is then led to unravel a narrative tangle made of many threads. The disparate nature of the book, its non-linear narrative, the plurality of stories and voices, the gaps in a fragmented, elliptic text all bear witness to an alternative approach to creative writing. Like a seamstress, the novelist pieces together individual stories, connecting them as the multifarious facets of a great whole. In the wake of francophone Haitian writers (namely Jacques Roumain, the author of Masters of the Dew, and Jacques Stephen Alexis who wrote General Sun, My Brother, Edwidge Danticat fictionalizes the traumatic history of a people confronted with violence and terror and engages in a complex intertextual game. Combining ethics and aesthetics, temporal and textual memory, the novelist explores facts and, rather than giving answers, raises difficult questions. Her characters, whether victims or perpetrators, all strive to free themselves from a haunting past: is it ever possible to forgive so as to heal the pain? Can one make amends for the harm that has been done to victims who seek redress?

Water harvest via dewing.

Science.gov (United States)

Lee, Anna; Moon, Myoung-Woon; Lim, Hyuneui; Kim, Wan-Doo; Kim, Ho-Young

2012-07-10

Harvesting water from humid air via dewing can provide a viable solution to a water shortage problem where liquid-phase water is not available. Here we experimentally quantify the effects of wettability and geometry of the condensation substrate on the water harvest efficiency. Uniformly hydrophilic surfaces are found to exhibit higher rates of water condensation and collection than surfaces with lower wettability. This is in contrast to a fog basking method where the most efficient surface consists of hydrophilic islands surrounded by hydrophobic background. A thin drainage path in the lower portion of the condensation substrate is revealed to greatly enhance the water collection efficiency. The optimal surface conditions found in this work can be used to design a practical device that harvests water as its biological counterpart, a green tree frog, Litoria caerulea , does during the dry season in tropical northern Australia.

Evaluation of the dew point cooling technology; Beoordeling technologie dauwpuntskoeling

Energy Technology Data Exchange (ETDEWEB)

Bootsveld, N.R.; Afink, J. [TNO Milieu, Energie en Procesinnovatie TNO-MEP, Amersfoort (Netherlands); Uges, P.G.H. (ed.) [Standex Periodieken, Veenendaal (Netherlands)

2003-01-01

Results of measurements on an indirect adiabatic dew point cooling system are presented and discussed. The cooling system has been developed by ComfortAir, Raalte, Netherlands. [Dutch] De meetresultaten van door ComfortAir in samenwerking met TNO-MEP uitgevoerde metingen aan een indirect werkende adiabatische dauwpuntkoeler worden gepresenteerd en besproken.

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

Science.gov (United States)

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.

A re-entrant resonator for the measurement of phase boundaries: dew points for {0.4026CH4 + 0.5974C3H8}

International Nuclear Information System (INIS)

Kandil, Mohamed E.; Marsh, Kenneth N.; Goodwin, Anthony R.H.

2005-01-01

For a natural gas and, especially, retrograde condensates, it is important for exploration and production that the (liquid + gas) phase boundary be known along with the ratio of liquid-to-gas volumes within the (liquid + gas) two-phase region. These fluid properties can be measured by a plethora of methods and here we report a method based on the measurement of the resonance frequency of the lowest order inductive-capacitance mode of a re-entrant cavity capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure, at T 4 + 0.5974C 3 H 8 }. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that suffer from quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within <±1 % of our results at temperature between (315 and 337) K while predictions obtained from the Soave Redlich Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these absolute differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K

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

Science.gov (United States)

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.

Impact of Continuous Cropping on the Diurnal Range of Dew Point Temperature during the Foliar Expansion Period of Annual Crops on the Canadian Prairies

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Bharat M. Shrestha

2016-01-01

Full Text Available It is important to increase our knowledge of the role of land use in changing the regional climate. This study asked, “Has the increase in continuous cropping over the past 50 years on the Canadian Prairies influenced the daily mean and range of morning dew point temperatures (Td during the foliar expansion period (from mid-June to mid-July of annual field crops?” We found that there has been a general increase in the decadal average of mean daily Td and in the range of morning Td from the 1960s to the 2000s. The increase in the observed range of Td between the daily minimum value, which typically occurs near sunrise, and the late morning peak was found to be related to the increase in annual crop acreage and consequent decrease in summerfallow area. The relationship was more significant in the subhumid climatic zone than in the semiarid climatic zone, and it was influenced by whether the region was experiencing either wet, normal, or dry conditions.

Measurement and estimation of dew point for SNG. [Comparison of calculated and measured values

Energy Technology Data Exchange (ETDEWEB)

Furuyama, Y.

1974-08-01

Toho Gas measured and estimated SNG dew points in high-pressure deliveries by calculating the theoretical values by the high-pressure gas-liquid equilibrium theory using the pressure-extrapolation method to reach K = 1, and the BWR method to estimate fugacity, then verifying these values experimentally. The experimental values were measured at 161.7 to 367.5 psi using the conventional static and circulation methods, in addition to a newly developed method consisting of circulating a known composition of gas mixtures, partially freezing them, and monitoring the dew point by observing the droplets on a mirror cooled by blowing liquid nitrogen. Good agreement was found between the calculated and the experimental values.

Environmental dew point and skin and lip weathering.

Science.gov (United States)

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.

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

Science.gov (United States)

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.

TFOS DEWS II Definition and Classification Report.

Science.gov (United States)

Craig, Jennifer P; Nichols, Kelly K; Akpek, Esen K; Caffery, Barbara; Dua, Harminder S; Joo, Choun-Ki; Liu, Zuguo; Nelson, J Daniel; Nichols, Jason J; Tsubota, Kazuo; Stapleton, Fiona

2017-07-01

The goals of the TFOS DEWS II Definition and Classification Subcommittee were to create an evidence-based definition and a contemporary classification system for dry eye disease (DED). The new definition recognizes the multifactorial nature of dry eye as a disease where loss of homeostasis of the tear film is the central pathophysiological concept. Ocular symptoms, as a broader term that encompasses reports of discomfort or visual disturbance, feature in the definition and the key etiologies of tear film instability, hyperosmolarity, and ocular surface inflammation and damage were determined to be important for inclusion in the definition. In the light of new data, neurosensory abnormalities were also included in the definition for the first time. In the classification of DED, recent evidence supports a scheme based on the pathophysiology where aqueous deficient and evaporative dry eye exist as a continuum, such that elements of each are considered in diagnosis and management. Central to the scheme is a positive diagnosis of DED with signs and symptoms, and this is directed towards management to restore homeostasis. The scheme also allows consideration of various related manifestations, such as non-obvious disease involving ocular surface signs without related symptoms, including neurotrophic conditions where dysfunctional sensation exists, and cases where symptoms exist without demonstrable ocular surface signs, including neuropathic pain. This approach is not intended to override clinical assessment and judgment but should prove helpful in guiding clinical management and research. Copyright © 2017 Elsevier Inc. All rights reserved.

DEWS (DEep White matter hyperintensity Segmentation framework): A fully automated pipeline for detecting small deep white matter hyperintensities in migraineurs.

Science.gov (United States)

Park, Bo-Yong; Lee, Mi Ji; Lee, Seung-Hak; Cha, Jihoon; Chung, Chin-Sang; Kim, Sung Tae; Park, Hyunjin

2018-01-01

Migraineurs show an increased load of white matter hyperintensities (WMHs) and more rapid deep WMH progression. Previous methods for WMH segmentation have limited efficacy to detect small deep WMHs. We developed a new fully automated detection pipeline, DEWS (DEep White matter hyperintensity Segmentation framework), for small and superficially-located deep WMHs. A total of 148 non-elderly subjects with migraine were included in this study. The pipeline consists of three components: 1) white matter (WM) extraction, 2) WMH detection, and 3) false positive reduction. In WM extraction, we adjusted the WM mask to re-assign misclassified WMHs back to WM using many sequential low-level image processing steps. In WMH detection, the potential WMH clusters were detected using an intensity based threshold and region growing approach. For false positive reduction, the detected WMH clusters were classified into final WMHs and non-WMHs using the random forest (RF) classifier. Size, texture, and multi-scale deep features were used to train the RF classifier. DEWS successfully detected small deep WMHs with a high positive predictive value (PPV) of 0.98 and true positive rate (TPR) of 0.70 in the training and test sets. Similar performance of PPV (0.96) and TPR (0.68) was attained in the validation set. DEWS showed a superior performance in comparison with other methods. Our proposed pipeline is freely available online to help the research community in quantifying deep WMHs in non-elderly adults.

EFFECT OF DEW POINT OF ATMOSPHERE OF CGL’S ANNEALING FURNACES ON THE QUALITY OF GA COATING ON BAKE HARDENABLE STEEL

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Juliana Porto Guimarães

2013-10-01

Full Text Available The strip steel surface condition after continuous annealing of strip is extremely important to the quality of galvannealed coating (GA. The presence of oxides or precipitated can affect the reactions at the coating/substrate interface and decrease the zinc wettability on the steel surface, leading to various defects in the final product. To avoid oxidation of the material during continuous annealing, a protective atmosphere is used in the furnaces. Despite this atmosphere, it is possible the selective oxidation or precipitation of second phase particles, being the dew point of atmosphere one of the leading factors to reduce this occurrence. This study aims to evaluate the effect of the dew point on the quality of GA coatings applied to a bake hardenable steel. The continuous annealing under dew points of –60°C, 30°C and 0°C, as well as hot dip galvanizing, were performed in a Hot Dip Process Simulator. It is found that the dew point has a decisive influence on the amount, distribution and type of oxides formed, and the condition of –30°C provided the coating with less failures and better adhesion.

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

Science.gov (United States)

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.

Effects of Engineered Wettability on the Efficiency of Dew Collection.

Science.gov (United States)

Gerasopoulos, Konstantinos; Luedeman, William L; Ölçeroglu, Emre; McCarthy, Matthew; Benkoski, Jason J

2018-01-31

Surface wettability plays an important role in dew collection. Nucleation is faster on hydrophilic surfaces, while droplets slide more readily on hydrophobic surfaces. Plants and animals in coastal desert environments appear to overcome this trade-off through biphilic surfaces with patterned wettability. In this study, we investigate the effects of millimeter-scale wettability patterns, mimicking those of the Stenocara beetle, on the rate of water collection from humid air. The rate of water collection per unit area is measured as a function of subcooling (ΔT = 1, 7, and 27 °C) and angle of inclination (from 10° to 90°). It is then compared for superbiphilic, hydrophilic, hydrophobic, and surperhydrophobic surfaces. For large subcooling, neither wettability nor tilt angle has a significant effect because the rate of condensation is so great. For 1 °C subcooling and large angles, hydrophilic surfaces perform best because condensation is the rate-limiting step. For low angles of inclination, superhydrophobic samples are best because droplet sliding is the rate-limiting step. Superbiphilic surfaces, in contrast to their superior fog collecting capabilities, generally collected dew at the slowest rate due to their inherent contact angle hysteresis. Theoretical considerations suggest that this finding may apply more generally to surfaces with patterned wettability.

Effect of Different Growth Stages and Dew Period Length on Disease Development of Alternaria alternata as a Biological Control Agent for Convolvulus arvensis

Directory of Open Access Journals (Sweden)

E Zeidali

2012-02-01

Full Text Available Abstract Field bindweed is an important perinial weed of agricultural crops word-wide. There are plant pathogen fungus which could cause necrotic spots on the leaves and stems of convolvulus arvensis under natural coditions. In order to evaluate the effects of weed growth stage and length of dew period on disease development causes by Aletrnaria alternata and Fusarium sp. two expriments were performed in the greenhouse based on a completely randomized design in factorial arrangement with four replications during 2006-2007. Spore concentration for both experiments was 107 spores per ml of distilled water. In the first experiment, treatments were different growth stages of field bindweed (cotyledon, 4-leaf, 6-leaf, 9-11-leaf stages. Results showed that disease development in the fungus of A. alternata was higher than Fusarium sp. The most susceptable growth stage of field bindweed plants to A. alternata was 2-4-leave stage. The second expriment was performed in order to study the effect of dew period length (6, 12, 24 and 48 hour dew periods on disease development at 4-leaf growth stage of field bindweed. The maximum disease development and minimum weed dry weight were observed with application of the fungus of A. alternata at dew periods of 24 and 48 hour, however, plant damage was also observed with a length of 6 hours dew period.

Theory, Electro-Optical Design, Testing, and Calibration of a Prototype Atmospheric Supersaturation, Humidity, and Temperature Sensor.

Science.gov (United States)

1982-07-15

Voltage versus Aspirated Dew Point 94 Hygrometer Reading in Degrees Celsius (10 Second Averages) Fig. (7.5)(b) Scatter Diagram - NCAR Lyman-Alpha...Hygrometer Output Voltage versus Aspirated Dew Point Hygrometer Reading in Degrees Celsius (10 Second Averages) Fig. (7.6) Ophir Air Temperature...goal thus translates to an absolute humidity accuracy of 1% of reading or better over a dynamic r-dnj(! ,(f i(jul. 4 uder. of magnitude. 29 - ITI VAP

Investigation on the Energy Saving Potential of Using a Novel Dew Point Cooling System in Data Centres

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Yin Bi

2017-10-01

Full Text Available Abstract: Information technology (IT has brought significant changes in people’s lives. As an important part of the IT industry, data centres (DCs have been rapidly growing in both the number and size over the past 40 years. Around 30% to 40% of electricity consumption in DCs is used for space cooling, thus leading to very inefficient DC operation. To identify ways to reduce the energy consumption for space cooling and increase the energy efficiency of DCs’ operation, a dedicated investigation into the energy usage in DCs has been undertaken and a novel high performance dew point cooling system was introduced into a DC operational scheme. Based on the cooling load in DCs, a case study was carried out to evaluate the energy consumptions and energy usage effectiveness when using the novel dew point cooling system in different scales of DCs in various climates. It was found that by using the novel dew point cooling system, for 10 typical climates a DC can have a much lower power usage effectiveness (PUE of 1.10 to 1.22 compared to that of 1.7 to 3.7 by using existing traditional cooling systems, leading to significantly increased energy efficiency of the DC operation. In addition, the energy performance by managing the cooling air supply at the different levels in DCs, i.e., room, row and rack level, was simulated by using a dynamic computer model. It was found that cooling air supply at rack level can provide a higher energy efficiency in DCs. Based on the above work, the energy saving potential in DCs was conducted by comparing DCs using an the novel dew point cooling system and the optimum management scheme for the cooling air supply to that using traditional air cooling systems and the same supply air management. Annual electricity consumptions for the two cases were given. It was found that by using the novel dew point cooling system and optimum management system for the cooling air supply, an 87.7~91.6% electricity consumption saving for

Effect of dew point on the formation of surface oxides of twinning-induced plasticity steel

International Nuclear Information System (INIS)

Kim, Yunkyum; Lee, Joonho; Shin, Kwang-Soo; Jeon, Sun-Ho; Chin, Kwang-Geun

2014-01-01

The surface oxides of twinning-induced plasticity (TWIP) steel annealed at 800 °C for 43 s were investigated using transmission electron microscopy. During the annealing process, the oxygen potential was controlled by adjusting the dew point in a 15%H 2 –N 2 gas atmosphere. It was found that the type of surface oxides formed and the thickness of the oxide layer were determined by the dew point. In a gas mixture with a dew point of − 20 °C, a MnO layer with a thickness of ∼ 100 nm was formed uniformly on the steel surface. Under the MnO layer, a MnAl 2 O 4 layer with a thickness of ∼ 15 nm was formed with small Mn 2 SiO 4 particles that measured ∼ 70 nm in diameter. Approximately 500 nm below the MnAl 2 O 4 layer, Al 2 O 3 was formed at the grain boundaries. On the other hand, in a gas mixture with a dew point of − 40 °C, a MnAl 2 O 4 layer with a thickness of ∼ 5 nm was formed on most parts of the surface. On some parts of the surface, Mn 2 SiO 4 particles were formed irregularly up to a thickness of ∼ 50 nm. Approximately 200 nm below the MnAl 2 O 4 layer, Al 2 O 3 was found at the grain boundaries. Thermodynamic calculations were performed to explain the experimental results. The calculations showed that when a O2 > ∼ 1.26 × 10 −28 , MnO, MnAl 2 O 4 , and Mn 2 SiO 4 can be formed together, and the major oxide is MnO. When a O2 is in the range of 1.26 × 10 −28 –2.51 × 10 −31 , MnO is not stable but MnAl 2 O 4 is the major oxide. When a O2 < ∼ 2.51 × 10 −31 , only Al 2 O 3 is stable. Consequently, the effective activity of oxygen is considered the dominant factor in determining the type and shape of surface oxides of TWIP steel. - Highlights: • The surface oxides of TWIP steel annealed at 800 °C were investigated using TEM. • The surface oxides were determined by the dew point during the annealing process. • The activity of oxygen is the major factor determining the oxides of TWIP steel

TFOS DEWS II pathophysiology report.

Science.gov (United States)

Bron, Anthony J; de Paiva, Cintia S; Chauhan, Sunil K; Bonini, Stefano; Gabison, Eric E; Jain, Sandeep; Knop, Erich; Markoulli, Maria; Ogawa, Yoko; Perez, Victor; Uchino, Yuichi; Yokoi, Norihiko; Zoukhri, Driss; Sullivan, David A

2017-07-01

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

Draught regulator with control flap lowers dew point, keeps stacks dry

Energy Technology Data Exchange (ETDEWEB)

Dreizler, U.; Dreizler, W.

1982-11-30

Draught regulators for auxiliary air are particularly important in older stacks operated with new boilers and burners. Owing to better ventilation during burner operation and standstill, the dew point of flue gases will be lowered so that water vapour condensation will be prevented. Postfitting of draught regulators will also help in stacks already damaged by condensation water. The draught regulator has a control flap for better control of auxiliary air supply.

Development of ultra low dew-point clean air generator; Cho tei roten seijo kuki hassei sochi no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Nishimura, H.; Okamura, N. [Takasago thermal Engineering Co., Ltd., Kanagawa (Japan)

2000-05-10

To reduce the manufacturing cost of semiconductors, some systems have been proposed that use a cheap and high purity Clean Dry Air (CDA). CDA can reduce process step such as wafer cleaning, because CDA flow in stocker prevents the wafer surface from adsorbing of moisture and organic impurities. We have already optimized a two-stage rotary dehumidifier and have conducted a study of methods for cheaply manufacturing air that has a low dew-point of -70 degree C to -50 degree C. We have further developed the method in which a dry dehumidifier is used, and developed an ultra low dew-point air generator. The air generator is a three-stage rotary dehumidifier in which a further stage is added to the two-stage rotary dehumidifier. The main component of the rotors is metal silicate. The air generator can supply dry air with a dew-point of -110 degree C. or less, in which the concentration in all gaseous contaminants is far below 1 ppb. We made a trial calculation of the manufacturing cost, and an average cost of 0.25 yen/m{sup 3} was obtained. (author)

Development of producing equipment of mixed butane-air with low dew point. Energy saving dewatering apparatus and 6A-Gas producing apparatus utilizing vaporization latent heat of butane and potential heat of air

Energy Technology Data Exchange (ETDEWEB)

Komine, Jin; Okada, Hiroto; Taniue, Nobuo; Tanoue, Keiju; Yamada, Tatsuhiko; Maekawa, Hisami; Murakami, Keiji

1988-02-10

A producing equipment of mixed butane-air with low dew point was developed. The dewatering was made during the period from the middle of May to the middle of October with high atmospheric humidity. The production capacity of the mixed gas is 3000 Nm/sup 3/ of 22% of butane and 78% of air per hour. The designed dew point is 18/sup 0/C or less under the pressure of 0.7 kg/cm/sup 2/G. The saturation temperature is 7.5/sup 0/C after the liquid butane is evacuated by a regulating valve. The air introduced into the dehumidifier through finned tubes is cooled to dewater based on those data. The partially vaporized butane is completely gasified by hot water in a vaporizer and mixed with the dewatered air by a venture mixer to produce the mixed butane-air. When the dewatering is incomplete, the spray nozzle must be just exchanged. The dew point of the produced gas was sufficiently below the designed value. The investment cost is low. The total operating cost is reduced by the remarkably decreased fuel cost though the power cost is increased. The noise level is low and the heat control is easy. (11 figs, 4 tabs, 1 photo)

An automated microlysimeter to study dew formation and evaporation in arid and semiarid regions

NARCIS (Netherlands)

Heusinkveld, B.G.; Berkowicz, S.M.; Jacobs, A.F.G.; Holtslag, A.A.M.; Hillen, W.C.A.M.

2006-01-01

The development of a simple and low-cost portable weighing microlysimeter that makes use of a load cell for automated recording and for studying daily dew formation, rate of accumulation, and subsequent evaporation in arid or semiarid regions during rainless seasons is presented. The sampling cup is

Wärtsilä turbocharger wash and dew point controller integration

OpenAIRE

Perälä, Antti

2013-01-01

There are two separate control cabinets used in Wärtsilä marine solutions, Turbocharger Wash Control and the Dew Point Control. The cabinets contain similar PLCs with I/O-cards needed in the system and touch screen for monitoring and controlling purposes. The purpose of the thesis was to find and implement a solution for integration of the control cabinets. The advantages of the integration are savings in material, space in the engine room and amount of work. The aim of the project was to cre...

Effect of dew point on the formation of surface oxides of twinning-induced plasticity steel

Energy Technology Data Exchange (ETDEWEB)

Kim, Yunkyum [Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136–713 (Korea, Republic of); Lee, Joonho, E-mail: joonholee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136–713 (Korea, Republic of); Shin, Kwang-Soo [Research Institute of Industrial Science and Technology, Pohang 790–600 (Korea, Republic of); Jeon, Sun-Ho; Chin, Kwang-Geun [POSCO Technical Research Laboratories, Gwangyang 545–090 (Korea, Republic of)

2014-03-01

The surface oxides of twinning-induced plasticity (TWIP) steel annealed at 800 °C for 43 s were investigated using transmission electron microscopy. During the annealing process, the oxygen potential was controlled by adjusting the dew point in a 15%H{sub 2}–N{sub 2} gas atmosphere. It was found that the type of surface oxides formed and the thickness of the oxide layer were determined by the dew point. In a gas mixture with a dew point of − 20 °C, a MnO layer with a thickness of ∼ 100 nm was formed uniformly on the steel surface. Under the MnO layer, a MnAl{sub 2}O{sub 4} layer with a thickness of ∼ 15 nm was formed with small Mn{sub 2}SiO{sub 4} particles that measured ∼ 70 nm in diameter. Approximately 500 nm below the MnAl{sub 2}O{sub 4} layer, Al{sub 2}O{sub 3} was formed at the grain boundaries. On the other hand, in a gas mixture with a dew point of − 40 °C, a MnAl{sub 2}O{sub 4} layer with a thickness of ∼ 5 nm was formed on most parts of the surface. On some parts of the surface, Mn{sub 2}SiO{sub 4} particles were formed irregularly up to a thickness of ∼ 50 nm. Approximately 200 nm below the MnAl{sub 2}O{sub 4} layer, Al{sub 2}O{sub 3} was found at the grain boundaries. Thermodynamic calculations were performed to explain the experimental results. The calculations showed that when a{sub O2} > ∼ 1.26 × 10{sup −28}, MnO, MnAl{sub 2}O{sub 4}, and Mn{sub 2}SiO{sub 4} can be formed together, and the major oxide is MnO. When a{sub O2} is in the range of 1.26 × 10{sup −28}–2.51 × 10{sup −31}, MnO is not stable but MnAl{sub 2}O{sub 4} is the major oxide. When a{sub O2} < ∼ 2.51 × 10{sup −31}, only Al{sub 2}O{sub 3} is stable. Consequently, the effective activity of oxygen is considered the dominant factor in determining the type and shape of surface oxides of TWIP steel. - Highlights: • The surface oxides of TWIP steel annealed at 800 °C were investigated using TEM. • The surface oxides were determined by the dew point

Projection of Korean Probable Maximum Precipitation under Future Climate Change Scenarios

Directory of Open Access Journals (Sweden)

Okjeong Lee

2016-01-01

Full Text Available According to the IPCC Fifth Assessment Report, air temperature and humidity of the future are expected to gradually increase over the current. In this study, future PMPs are estimated by using future dew point temperature projection data which are obtained from RCM data provided by the Korea Meteorological Administration. First, bias included in future dew point temperature projection data which is provided on a daily basis is corrected through a quantile-mapping method. Next, using a scale-invariance technique, 12-hour duration 100-year return period dew point temperatures which are essential input data for PMPs estimation are estimated from bias-corrected future dew point temperature data. After estimating future PMPs, it can be shown that PMPs in all future climate change scenarios (AR5 RCP2.6, RCP 4.5, RCP 6.0, and RCP 8.5 are very likely to increase.

Mechanisms of corrosion, falling short of dew point and formation of corrosion in boilers and exhaust systems. Mechanismen der Korrosionsbildung, der Taupunktunterschreitung und Entstehung von Korrosionen in Kessel- und Abgassystemen

Energy Technology Data Exchange (ETDEWEB)

Marx, E.

1994-09-01

In order to save energy boilers for heating systems are run on increasingly lower exhaust gas- and boiler temperatures. Combustion as such depends of type of fuel, boiler and burner design, design of exhaust systems and atmospheric disturbance variables. This article looks at the influence which these factors have on corrosion. Falling short of the dew point is an important parameter in this context. Possibilities of avoiding corrosion are explained. (BWI)

Characterization of Bacterial and Fungal Community Dynamics by High-Throughput Sequencing (HTS Metabarcoding during Flax Dew-Retting

Directory of Open Access Journals (Sweden)

Christophe Djemiel

2017-10-01

Full Text Available Flax dew-retting is a key step in the industrial extraction of fibers from flax stems and is dependent upon the production of a battery of hydrolytic enzymes produced by micro-organisms during this process. To explore the diversity and dynamics of bacterial and fungal communities involved in this process we applied a high-throughput sequencing (HTS DNA metabarcoding approach (16S rRNA/ITS region, Illumina Miseq on plant and soil samples obtained over a period of 7 weeks in July and August 2014. Twenty-three bacterial and six fungal phyla were identified in soil samples and 11 bacterial and four fungal phyla in plant samples. Dominant phyla were Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes (bacteria and Ascomycota, Basidiomycota, and Zygomycota (fungi all of which have been previously associated with flax dew-retting except for Bacteroidetes and Basidiomycota that were identified for the first time. Rare phyla also identified for the first time in this process included Acidobacteria, CKC4, Chlorobi, Fibrobacteres, Gemmatimonadetes, Nitrospirae and TM6 (bacteria, and Chytridiomycota (fungi. No differences in microbial communities and colonization dynamics were observed between early and standard flax harvests. In contrast, the common agricultural practice of swath turning affects both bacterial and fungal community membership and structure in straw samples and may contribute to a more uniform retting. Prediction of community function using PICRUSt indicated the presence of a large collection of potential bacterial enzymes capable of hydrolyzing backbones and side-chains of cell wall polysaccharides. Assignment of functional guild (functional group using FUNGuild software highlighted a change from parasitic to saprophytic trophic modes in fungi during retting. This work provides the first exhaustive description of the microbial communities involved in flax dew-retting and will provide a valuable benchmark in future studies aiming

Development of manufacturing of low dew-point mixed gas of butane-air

Energy Technology Data Exchange (ETDEWEB)

Komine, Hitoshi

1988-09-10

A dehumidifying plant was installed to supply high-quality dehumidified butane-air mixed gas aiming at saving the heat required for vaporizing liquid butane by the heat exchange with the potential heat of air as well as the dehumidification of the air used for the mixed gas by cooling with the vaporizing latent heat of liquid butane. The plant has been smoothly operated since August, 1987. Butane sent from the air-dehumidifier is completely vaporized by hot water in the vaporizer and the vaporized butane ejected by the Venturi mixer to mix with the dehumidified air. The gas production capacity is 3000Nm/sup 3//h and the treating capacities of butane and air are 661 and 2339 Nm/sup 3//h, respectively. The dew point of the mixed gas is 18/sup 0/C under 0.7kg/cm/sup 2/G at atmospheric temperature of 38/sup 0/C subject to the operation of the plant only in hot and humid summer. It was demonstrated that the plant is characterized by low construction and operating costs, low level of noise and stable heat value of the product gas. (5 figs, 4 tabs, 1 photo)

Dew point, internal gas pressure, and chemical composition of the gas within the free volume of DWPF canistered waste forms

International Nuclear Information System (INIS)

Harbour, J.R.; Herman, D.T.; Crump, S.; Miller, T.J.; McIntosh, J.

1996-01-01

The Defense Waste Processing Facility (DWPF) produced 55 canistered waste forms containing simulated waste glass during the four Waste Qualification campaigns of the DWPF Startup Test Program. Testing of the gas within the free volume of these canisters for dew point, internal gas pressure, and chemical composition was performed as part of a continuing effort to demonstrate compliance with the Waste Acceptance Product Specifications. Results are presented for six glass-filled canisters. The dew points within the canisters met the acceptance criterion of < 20 degrees C for all six canisters. Factors influencing the magnitude of the dew point are presented. The chemical composition of the free volume gas was indistinguishable from air for all six canisters. Hence, no foreign materials were present in the gas phase of these canisters. The internal gas pressures within the sealed canisters were < 1 atm at 25 degrees C for all six canisters which readily met the acceptance criterion of an internal gas pressure of less than 1.5 atm at 25 degrees C. These results provided the evidence required to demonstrate compliance with the Waste Acceptance Product Specifications

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

DEFF Research Database (Denmark)

Engebretsen, K A; Johansen, J D; Kezic, S

2016-01-01

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...

Dew point of gases with low sulfuric acid content

Energy Technology Data Exchange (ETDEWEB)

Fieg, J.

1981-07-01

Discusses control of air pollution caused by sulfur compounds in solid fuels during combustion. Excessive amount of oxygen during combustion leads to formation of sulfur trioxide. Sulfur trioxide reacts with water vapor and forms sulfuric acid. Chemical reactions which lead to formation of sulfuric acid are described. Conditions for sulfuric acid condensation are analyzed. Several methods for determining dew point of flue gases with low sulfuric acid content are reviewed: methods based on determination of electric conductivity of condensed sulfuric acid (Francis, Cheney, Kiyoure), method based on determination of sulfuric acid concentration in the gaseous phase and in the liquid phase after cooling (Lee, Lisle and Sensenbaugh, Ross and Goksoyr). (26 refs.) (In Polish)

Flooding During Drought: Learning from Stakeholder Engagement & Partner Coordination in the California-Nevada Drought Early Warning System (DEWS)

Science.gov (United States)

Sheffield, A. M.

2017-12-01

After more than 5 years of drought, extreme precipitation brought drought relief in California and Nevada and presents an opportunity to reflect upon lessons learned while planning for the future. NOAA's National Integrated Drought Information System (NIDIS) California-Nevada Drought Early Warning System (DEWS) in June 2017 convened a regional coordination workshop to provide a forum to discuss and build upon past drought efforts in the region and increase coordination, collaboration and information sharing across the region as a whole. Participants included federal, tribal, state, academic, and local partners who provided a post-mortem on the recent drought and impacts as well as recent innovations in drought monitoring, forecasts, and decision support tools in response to the historic drought. This presentation will highlight lessons learned from stakeholder outreach and engagement around flooding during drought, and pathways for moving forward coordination and collaboration in the region. Additional focus will be on the potential opportunities from examining California decision making calendars from this drought. Identified gaps and challenges will also be shared, such as the need to connect observations with social impacts, capacity building around available tools and resources, and future drought monitoring needs. Drought will continue to impact California and Nevada, and the CA-NV DEWS works to make climate and drought science readily available, easily understandable and usable for decision makers; and to improve the capacity of stakeholders to better monitor, forecast, plan for and cope with the impacts of drought.

Test and evaluation of the Fort St. Vrain dew point moisture monitor system

International Nuclear Information System (INIS)

Block, G.A.; Del Bene, J.V. Jr.; Gitterman, M.; Hastings, G.A.; Hawkins, W.M.; Hinz, R.F.; McCue, D.E.; Swanson, L.L.; Vavrina, J.; Zwetzig, G.B.

1975-01-01

Descriptions are given of the Fort St. Vrain Dew Point Moisture Monitor (DPMM) System; the bases for the DPMM system response time requirements for safety related functions at the required reactor operating conditions; the results and evaluation of recent testing which measured the performance of the current system at simulated operating conditions; predicted response times for reactor power operation from 0 to 100 percent and a modification to provide improved response times for low-load and plant start-up conditions

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

Science.gov (United States)

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 ...

A dew point signaller for conservation of works of art.

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Nowcasting Surface Meteorological Parameters Using Successive Correction Method

National Research Council Canada - National Science Library

Henmi, Teizi

2002-01-01

The successive correction method was examined and evaluated statistically as a nowcasting method for surface meteorological parameters including temperature, dew point temperature, and horizontal wind vector components...

Prediction of the critical point and the dew- and bubble-point curves fo natural gases. Tennen gas no rinkaiten oyobi roten futten kyokusen no suisan

Energy Technology Data Exchange (ETDEWEB)

Endo, T. (Hitachi, Ltd., Tokyo (Japan)); Arai, D.; Uematsu, M. (Keio University, Tokyo (Japan). Faculty of Science and Technology)

1993-02-25

Related to the natural gas transport by pipeline, etc., the critical point, dew point and bubble point of natural gas were presumed by calculation through equation of state for determining the exact thermophysical values. The natural gas is multi-component mixed fluid which is represented by methane as a representative component. It considerably differs in composition by its place of origin. Because the conventional method was complicated in process for thermodynamically determining the most stable composition of phases, algorithm of phasic equilibrium was applied by the equation of state which used the discrimination method by Nitta, et al. for the therodynamic stability of phases. The method by Michelsen was applied to the flash calculation, and figuration of both dew point and bubble point curves, while that by Heidemann, et al. was done to the critical point calculation. Peng-Robinson's was applied to an equation of state. To start the calculation, the constant of seven two-component systems the main component of which was methane was determined as a function of temperature based on the actually measured gas/liquid equilibrium value. Then, possibility of calculatively presuming the thermophysical values was shown through comparison of the actually measured values with those obtained by applying the present method to the above systems. Finally, the presumption was made for the natural gas which differed in place of origin. 17 refs., 15 figs., 2 tabs.

Experimental investigation of carbon monoxide poisoning effect on a PBI/H3PO4 high temperature polymer electrolyte membrane fuel cell

DEFF Research Database (Denmark)

Zhou, Fan; Andreasen, Søren Juhl; Kær, Søren Knudsen

2015-01-01

humidity level reduced the cell performance loss caused by CO poisoning. When the fuel cell was operated with pure H2, the cell performance was not significantly affect by the change in anode dew point temperature in the range of room temperature and 60 °C. CO2 in anode stream resulted in slight decrease...

Technology assessment of dew point cooling; Beoordeling technologie dauwpuntskoeling

Energy Technology Data Exchange (ETDEWEB)

Uges, P.G.H. [Koudetechnisch Centrum, Nijmegen (Netherlands); Reinder, T.M.

2003-03-01

Results of measurements on an indirect adiabatic dew point cooling system are presented and discussed. The cooling system has been developed by OxyCom (formerly ComfortAir), Raalte, Netherlands. [Dutch] De techniek van dauwpuntskoeling is gebaseerd op bet principe van indirecte verdamping van water in een secundair circuit, waarbij geen extra vocht aan de te koelen luchtstroom wordt toegevoegd en waarmee luchttemperaturen worden bereikt die net boven het dauwpunt liggen en dus onder de natteboltemperatuur. Dauwpuntskoeling is een technische ontwikkeling met goede toekomstverwachtingen. Voorzover bekend zijn er tot op heden geen meetgegevens gepubliceerd met een dergelijke indirect werkende koeler. Dit artikel geeft de meetresultaten weer van een door OxyCorn in samenwerking met TNO-MEP uitgevoerd meetprogramma. Dit artikel is gebaseerd op de TNO-MEP rapportage met als auteurs N.R. Bootsveld en J. Afink en heeft eerder in het blad Koude en Luchtbehandeling, januari 2003, gestaan.

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

Science.gov (United States)

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.

Parametric analysis of a combined dew point evaporative-vapour compression based air conditioning system

Directory of Open Access Journals (Sweden)

Shailendra Singh Chauhan

2016-09-01

Full Text Available A dew point evaporative-vapour compression based combined air conditioning system for providing good human comfort conditions at a low cost has been proposed in this paper. The proposed system has been parametrically analysed for a wide range of ambient temperatures and specific humidity under some reasonable assumptions. The proposed system has also been compared from the conventional vapour compression air conditioner on the basis of cooling load on the cooling coil working on 100% fresh air assumption. The saving of cooling load on the coil was found to be maximum with a value of 60.93% at 46 °C and 6 g/kg specific humidity, while it was negative for very high humidity of ambient air, which indicates that proposed system is applicable for dry and moderate humid conditions but not for very humid conditions. The system is working well with an average net monthly power saving of 192.31 kW h for hot and dry conditions and 124.38 kW h for hot and moderate humid conditions. Therefore it could be a better alternative for dry and moderate humid climate with a payback period of 7.2 years.

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

Science.gov (United States)

Nguyen, Jennifer L; Dockery, Douglas W

2016-02-01

The health consequences of heat and cold are usually evaluated based on associations with outdoor measurements collected at a nearby 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. These results suggest that, in general, outdoor measures of actual moisture content in air better capture indoor conditions than outdoor temperature and relative humidity. Therefore, in studies where water vapor is among the parameters of interest for examining weather-related health effects, outdoor measurements of actual moisture content can be more reliably used as a proxy for indoor exposure than the more commonly examined variables of temperature and relative humidity.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Warm Season Statistical Verification of the Pennsylvania State University Real Time Mesoscale Model Version 5

National Research Council Canada - National Science Library

Fitzgerald, Mark

1998-01-01

.... Variables that are verified include temperature, dew point, relative humidity, wind direction, wind speed, geopotential height, sea-level pressure, as well as the total totals severe weather index...

A method for high accuracy determination of equilibrium relative humidity

DEFF Research Database (Denmark)

Jensen, O.M.

2012-01-01

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

Numerical investigation of the energy performance of a guideless irregular heat and mass exchanger with corrugated heat transfer surface for dew point cooling

International Nuclear Information System (INIS)

Xu, Peng; Ma, Xiaoli; Diallo, Thierno M.O.; Zhao, Xudong; Fancey, Kevin; Li, Deying; Chen, Hongbing

2016-01-01

The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy efficiency (i.e. Coefficient of Performance (COP)) of the air cooling process. CFD simulation was carried out to determine the flow resistance (K) factors of various elements within the dry and wet channels of the exchanger, while the ‘finite-element’ based ‘Newton-iteration’ numerical simulation was undertaken to investigate its cooling capacity, cooling effectiveness and COP at various geometrical and operational conditions. Compared to the existing flat-plate heat and mass exchangers with the same geometrical dimensions and operational conditions, the new irregular exchanger could achieve 32.9%–37% higher cooling capacity, dew-point and wet-bulb effectiveness, 29.7%–33.3% higher COP, and 55.8%–56.2% lower pressure drop. While undertaking dew point air cooling, the irregular heat and mass exchanger had the optimum air velocity of 1 m/s within the flow channels and working-to-intake air ratio of 0.3, which allowed the highest cooling capacity and COP to be achieved. In terms of the exchanger dimensions, the optimum height of the channel was 5 mm while its length was in the range 1–2 m. Overall, the proposed irregular heat and mass exchanger could lead to significant enhanced energy performance compared to the existing flat-plate dew point cooling heat exchanger of the same geometrical dimensions. To achieve the same amount cooling output, the irregular heat and mass exchanger had the reduced size and cost against the flat-plate ones. - Highlights: • Numerical investigation of an irregular heat and mass exchanger was undertaken. • A �

Simulations of tokamak disruptions including self-consistent temperature evolution

International Nuclear Information System (INIS)

Bondeson, A.

1986-01-01

Three-dimensional simulations of tokamaks have been carried out, including self-consistent temperature evolution with a highly anisotropic thermal conductivity. The simulations extend over the transport time-scale and address the question of how disruptive current profiles arise at low-q or high-density operation. Sharply defined disruptive events are triggered by the m/n=2/1 resistive tearing mode, which is mainly affected by local current gradients near the q=2 surface. If the global current gradient between q=2 and q=1 is sufficiently steep, the m=2 mode starts a shock which accelerates towards the q=1 surface, leaving stochastic fields, a flattened temperature profile and turbulent plasma behind it. For slightly weaker global current gradients, a shock may form, but it will dissipate before reaching q=1 and may lead to repetitive minidisruptions which flatten the temperature profile in a region inside the q=2 surface. (author)

Application of model MTS5 dew-point meter in gas sampling and analyzing system of HTR-10

International Nuclear Information System (INIS)

Zhu Jiang; Li Zhihui

2010-01-01

The feature of humidity detector to measure the content of water in pure helium of main loop of reactor was discussed, and the circumstances using Al 2 O 3 moisture sensor to measure the content of water in helium on-line were introduced. During those few years, the dew-point meter has sufficed to measure the content of water in the helium gas during the running of the reactor. On the other hand, excursion can happen when the instrument running. Demarcate must be made periodically to improve the veracity of the meter. (authors)

Delivery of State-Provided Predictive Analytics to Schools: Wisconsin's DEWS and the Proposed EWIMS Dashboard. WCER Working Paper No. 2016-3

Science.gov (United States)

Clune, Bill; Knowles, Jared

2016-01-01

Since 2012, the Wisconsin Department of Public Instruction (DPI) has maintained a statewide predictive analytics system providing schools with an early warning in middle grades of students at risk for not completing high school. DPI is considering extending and enhancing this system, known as the Dropout Early Warning System (DEWS). The proposed…

Extreme precipitation response to climate perturbations in an atmospheric mesoscale model

NARCIS (Netherlands)

Attema, J.J.; Loriaux, J.M.; Lenderink, G.

2014-01-01

Observations of extreme (sub) hourly precipitation at midlatitudes 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

Prediction of water formation temperature in natural gas dehydrators using radial basis function (RBF neural networks

Directory of Open Access Journals (Sweden)

Tatar Afshin

2016-03-01

Full Text Available Raw natural gases usually contain water. It is very important to remove the water from these gases through dehydration processes due to economic reasons and safety considerations. One of the most important methods for water removal from these gases is using dehydration units which use Triethylene glycol (TEG. The TEG concentration at which all water is removed and dew point characteristics of mixture are two important parameters, which should be taken into account in TEG dehydration system. Hence, developing a reliable and accurate model to predict the performance of such a system seems to be very important in gas engineering operations. This study highlights the use of intelligent modeling techniques such as Multilayer perceptron (MLP and Radial Basis Function Neural Network (RBF-ANN to predict the equilibrium water dew point in a stream of natural gas based on the TEG concentration of stream and contractor temperature. Literature data set used in this study covers temperatures from 10 °C to 80 °C and TEG concentrations from 90.000% to 99.999%. Results showed that both models are accurate in prediction of experimental data and the MLP model gives more accurate predictions compared to RBF model.

Modeling of atmospheric corrosion environments and its application to constant dew-point corrosion test; Yagai taiki fushoku kankyo no modeling to sore ni motozuku teirotengata saikuru fushoku shikenho no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Muto, I. [Nippon Steel Corp., Tokyo (Japan)] Sugimoto, K. [Tohoku Univ., Sendai (Japan)

1998-08-15

Recently, stainless steel is increasing its demand for corrosion resistant building materials. Then, as it is necessary to develop and accelerating testing method capable of accurately estimating weatherability at sea side area, such testing method has no been developed yet because of difficulty to quantify corrosive environment relating to atmospheric corrosion phenomenon. As air temperature and relative humidity in outdoor change in complex, specific temperature and relative humidity cannot be used for their representative values. And, construction of corrosive factors such as sea salt particles, and so on are also much different at each area. However, at coastal area, a dew water dissolving the sea salt particles, so called droplets of chlorides aqueous solution is formed onto material surface. Then, in this study, on a base of drying and humidity absorption behavior and daily change behavior of temperature and humidity in outdoor, modeling of atmospheric corrosion environment was tried. An accelerating testing method according to this modeling was developed, long-term weathering test was compared with the corrosion behavior of the same steel, and validity of a new accelerating testing method was evaluated. 22 refs., 12 figs., 2 tabs.

Will the warmer temperature bring the more intensity precipitation?

Science.gov (United States)

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

Thermodynamic analysis of high-temperature regenerative organic Rankine cycles using siloxanes as working fluids

International Nuclear Information System (INIS)

Fernandez, F.J.; Prieto, M.M.; Suarez, I.

2011-01-01

A recent novel adjustment of the Span-Wagner equation of state for siloxanes, used as working fluids in high-temperature organic Rankine cycles, is applied in a mathematical model to solve cycles under several working conditions. The proposed scheme includes a thermo-oil intermediate heat circuit between the heat source and the organic Rankine cycle. Linear and cyclic siloxanes are assayed in saturated, superheated and supercritical cycles. The cycle includes an internal heat exchanger (regenerative cycle), although a non-regenerative scheme is also solved. In the first part of the study, a current of combustion gases cooled to close to their dew point temperature is taken as the reference heat source. In the second part, the outlet temperature of the heat source is varied over a wide range, determining appropriate fluids and schemes for each thermal level. Simple linear (MM, MDM) siloxanes in saturated regenerative schemes show good efficiencies and ensure thermal stability of the working fluid. -- Highlights: → Organic Rankine cycles with polymethylsiloxanes as working fluids were modelled. → The cycle scheme is regenerative and includes an intermediate heat transfer fluid. → The fluid properties were calculated by means of the Span-Wagner equation of state. → Vapour conditions to the expander and source thermal level were analysed. → Siloxanes MM, MDM and D 4 under saturated conditions were the best options.

A technical basis to relax the dew point specification for the environment in the vapor space in DWPF canisters

International Nuclear Information System (INIS)

Louthan, M.R. Jr.

1995-05-01

This memorandum establishes the technical basis to conclude that relaxing, from 0 C to 20 C, the dew point specification for the atmosphere in the vapor space (free volume) of a DWPF canister will not provide an environment that will cause significant amounts of corrosion induced degradation of the canister wall. The conclusion is based on engineering analysis, experience and review of the corrosion literature. The basic assumptions underlying the conclusion are: (1) the canister was fabricated from Type 304L stainless steel; (2) the corrosion behavior of the canister material, including base metal, fusion zones and heat effected zones, is typified by literature data for, and industrial experience with, 300 series austenitic stainless steels; and (3) the glass-metal crevices created during the pouring operation will not alter the basic corrosion resistance of the steel although such crevices might serve as sites for the initiation of minor amounts of corrosion on the canister wall

Advances in thermal control and performance of the MMT M1 mirror

Science.gov (United States)

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.

AgMIP wheat pilot data 4 release

OpenAIRE

Asseng, S.; Ewert, F.; Martre, P.; Supit, I.; Wolf, J.

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 soi...

Parameter measurement of target

International Nuclear Information System (INIS)

Gao Dangzhong

2001-01-01

The progress of parameter measurement of target (ICF-15) in 1999 are presented, including the design and contract of the microsphere equator profiler, the precise air bearing manufacturing, high-resolution X-ray image of multi-layer shells and the X-ray photos processed with special image and data software, some plastic shells measured in precision of 0.3 μm, the high-resolution observation and photograph system of 'dew-point method', special fixture of target and its temperature distribution measuring, the dew-point temperature and fuel gas pressure of shells measuring with internal pressure of 5 - 15 (x10 5 ) Pa D 2 and wall thickness of 1.5∼3 μm

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Controlled humidity gas circulators

International Nuclear Information System (INIS)

Gruner, S.M.

1981-01-01

A programmable circulator capable of regulating the humidity of a gas stream over a wide range of humidity is described. An optical dew-point hygrometer is used as a feedback element to control the addition or removal of water vapor. Typical regulation of the gas is to a dew-point temperature of +- 0.2 0 C and to an accuracy limited by the dew-point hygrometer

A physically based analytical spatial air temperature and humidity model

Science.gov (United States)

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.

Micrometeorological data for energy-budget studies near Rogers Spring, Ash Meadows National Wildlife Refuge, Nye County, Nevada, 1994

International Nuclear Information System (INIS)

Nichols, W.D.; Rapp, T.R.

1996-01-01

The data were collected at two sites near Rogers Spring for use in energy-budget studies beginning in 1994. The data collected at each site included net radiation, air temperature at two heights, dew- point temperature at two heights, windspeed at two heights, soil heat flux, and soil temperature in the interval between the land surface and the buried heat-flux plates

A study on the effects of system pressure on heat and mass transfer rates of an air cooler

International Nuclear Information System (INIS)

Jung, Hyung Ho

2002-01-01

In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements

Dew drops on spider web appearance: a newly named pattern of IgG4 deposition in pemphigus with direct immunofluorescence

Directory of Open Access Journals (Sweden)

Marian Dmochowski

2017-08-01

Full Text Available Novel appearances in cutaneous pathology as well as mucocutaneous clinical signs are being described which indicate that this is still an attractive area for exploration. The H + E histology terms of “decorated tomb stoning” and “undecorated tomb stoning”, advocated by some pathologists, are misleading and as such should be avoided. Here, an appearance of IgG4 pemphigus deposits examined cost-effectively with direct immunofluorescence and suggested to be called “dew drops on spider web” is depicted in depth.

Influência do orvalho e volume de calda de aplicação na eficácia do glyphosate na dessecação de Brachiaria plantaginea Influence of dew and spray volume on the efficacy of glyphosate for Brachiaria plantaginea burndown

Directory of Open Access Journals (Sweden)

E.S. Roman

2004-09-01

Full Text Available A eficácia de herbicidas é influenciada por diversos fatores que afetam a absorção e a translocação desses compostos na planta. A absorção de herbicidas pelas plantas, por exemplo, é influenciada, tanto física como biologicamente, pela temperatura e pela umidade relativa do ar dentro do dossel. Com a diminuição da umidade relativa do ar e/ou com o aumento da temperatura, as gotas da pulverização secam mais rapidamente e a absorção do produto diminui, ou até mesmo cessa, afetando o desempenho biológico. Com base nessa premissa, o presente estudo teve como objetivo examinar a influência do orvalho e do volume de calda de aplicação na eficiência de doses de glyphosate para o controle de Brachiaria plantaginea. Foram observadas interações significativas entre volume de calda, orvalho e dose de glyphosate. O volume mais baixo (100 L ha-1 resultou em melhor controle da espécie, especialmente quando o herbicida foi usado na menor dose (90 g ha-1. A presença de orvalho nas folhas causou reduções na atividade do produto, especialmente quando aplicado na menor dose e combinado com maior volume de calda.The efficacy of herbicides is influenced by several factors affecting the absorption and translocation of these compounds in the plant. Herbicide plant absorption, for example, is both physically and biologically influenced by temperature and air relative humidity in the plant canopy. With the reduction in relative air humidity and/or increase in temperature, the spray droplets dry more rapidly and the absorption of the herbicide decreases or even stops, affecting the biological performance. Based on that, this research aimed to study the influence of dew and spray volume on the efficacy of glyphosate rates in the control of B. plantaginea. There were significant interactions among volume of water, dew and rate of glyphosate. The lower the water volume, the more effective the glyphosate activity was, especially when applied at

Improving indoor air quality through the use of continual multipoint monitoring of carbon dioxide and dew point.

Science.gov (United States)

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.

The Mollier diagram in theory and practice. Part 3. Examples on Calculation of Dew Point Cooling; Het Mollierdiagram in theorie en praktijk. Deel 3. Rekenvoorbeelden Dauwpuntkoeling

Energy Technology Data Exchange (ETDEWEB)

Kouwenhoven, H.J.L. [Frigidarium, Driebergen-Rijsenburg (Netherlands); Huizinga, H.T. [Heat Transfer Holland HTH, Zuidwolde (Netherlands); Bootsveld, N.R. [YNO, Delft (Netherlands); Janssen, M. [Re-gent, Helmond (Netherlands); Uges, P.G.H. [StatiqCooling, Deventer (Netherlands)

2007-04-15

The use of direct and indirect adiabatic cooling, and recently in particular indirect diabatic cooling (dew point cooling) require knowledge of the Mollier diagram. [Dutch] Het gebruik van direct en indirect werkende adiabatische koeling en recentlijk vooral de indirect werkende systemen zoals diabatische koeling (dauwpuntkoeling, al of niet uitgevoerd als statische koeling) vragen om kennis van het Mollierdiagram.

CANDU pressure tube leak detection by annulus gas dew point measurement. A critical review

International Nuclear Information System (INIS)

Greening, F.R.

2017-01-01

In the event of a pressure tube leak from a small through-wall crack during CANDU reactor operations, there is a regulatory requirement - referred to as Leak Before Break (LBB) - for the licensee to demonstrate that there will be sufficient time for the leak to be detected and the reactor shut down before the crack grows to the critical size for fast-uncontrolled rupture. In all currently operating CANDU reactors, worldwide, this LBB requirement is met via continuous dew point measurements of the CO_2 gas circulating in the reactor's Annulus Gas System (AGS). In this paper the historical development and current status of this leak detection capability is reviewed and the use of moisture injection tests as a verification procedure is critiqued. It is concluded that these tests do not represent AGS conditions that are to be expected in the event of a real pressure tube leak.

CANDU pressure tube leak detection by annulus gas dew point measurement. A critical review

Energy Technology Data Exchange (ETDEWEB)

Greening, F.R. [CTS-NA, Tiverton, ON (Canada)

2017-03-15

In the event of a pressure tube leak from a small through-wall crack during CANDU reactor operations, there is a regulatory requirement - referred to as Leak Before Break (LBB) - for the licensee to demonstrate that there will be sufficient time for the leak to be detected and the reactor shut down before the crack grows to the critical size for fast-uncontrolled rupture. In all currently operating CANDU reactors, worldwide, this LBB requirement is met via continuous dew point measurements of the CO{sub 2} gas circulating in the reactor's Annulus Gas System (AGS). In this paper the historical development and current status of this leak detection capability is reviewed and the use of moisture injection tests as a verification procedure is critiqued. It is concluded that these tests do not represent AGS conditions that are to be expected in the event of a real pressure tube leak.

Influence of Gas Atmosphere Dew Point on the Galvannealing of CMnSi TRIP Steel

Science.gov (United States)

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.

A sub-circuit MOSFET model with a wide temperature range including cryogenic temperature

Energy Technology Data Exchange (ETDEWEB)

Jia Kan; Sun Weifeng; Shi Longxing, E-mail: jiakan.01@gmail.com [National ASIC System Engineering Research Center, Southeast University, Nanjing 210096 (China)

2011-06-15

A sub-circuit SPICE model of a MOSFET for low temperature operation is presented. Two resistors are introduced for the freeze-out effect, and the explicit behavioral models are developed for them. The model can be used in a wide temperature range covering both cryogenic temperature and regular temperatures. (semiconductor devices)

Catalysts macroporosity and their efficiency in sulphur sub-dew point Claus tail gas treating processes

Energy Technology Data Exchange (ETDEWEB)

Tsybulevski, A.M.; Pearson, M. [Alcoa Industrial Chemicals, 16010 Barker`s Point Lane, Houston, TX (United States); Morgun, L.V.; Filatova, O.E. [All-Russian Research Institute of Natural Gases and Gas Technologies VNIIGAZ, Moscow (Russian Federation); Sharp, M. [Porocel Corporation, Westheimer, Houston, TX (United States)

1996-10-08

The efficiency of 4 samples of alumina catalyst has been studied experimentally in the course of the Claus `tail gas` treating processes at the sulphur sub-dew point (TGTP). The samples were characterized by the same chemical and crystallographic composition, the same volume of micropores, the same surface area and the same catalytic activity but differed appreciably in the volume of macropores. An increase in the effective operation time of the catalysts before breakthrough of unrecoverable sulphur containing compounds, with the increasing macropore volume has been established. A theoretical model of the TGTP has been considered and it has been shown that the increase in the sulphur capacity of the catalysts with a larger volume of macropores is due to an increase in the catalysts efficiency factor and a slower decrease in their diffusive permeability during filling of micropores by sulphur

Enhanced battery model including temperature effects

NARCIS (Netherlands)

Rosca, B.; Wilkins, S.

2013-01-01

Within electric and hybrid vehicles, batteries are used to provide/buffer the energy required for driving. However, battery performance varies throughout the temperature range specific to automotive applications, and as such, models that describe this behaviour are required. This paper presents a

Determination of equilibrium phase composition in the Hg-HgTe-CdTe system by ''dew point'' method

International Nuclear Information System (INIS)

Vanyukov, A.V.; Krotov, I.I.; Ermakov, A.I.

1978-01-01

Using the ''dew point'' method a study has been made of the equilibrium composition of the solid and liquid phases in the Hg-HgTe-CdTe system at 404, 435 and 454 deg C. It has been pointed out that crystallization of cadmium-rich solid solutions of Cdsub(x)Hgsub(1-x) Te takes place from a liquid phase with a much higher concentration of Hg. The activity of Hg in the liquid phase increases along the liquidus isotherm in the direction from section Hg-HgTe to section HgCdTe in accordance with the increase of its concentration. An increase in activity of Hg in the solid phase of Cdsub(x)Hgsub(1-x)Te has been noted with the reduction of its concentration

Machine-Learning Techniques for the Determination of Attrition of Forces Due to Atmospheric Conditions

Science.gov (United States)

2018-02-01

selected as a proof of concept due to its vast number of data points. While this report does note some trends associated with temperature and dew...separate data sets for helicopters and airplanes, while selectively requesting the event IDs, descriptions of events, light conditions, temperature , dew...weather events) and the error rate for that class . The rows are labeled for the actual occurrence of those events. Thus, for every row–column

Effect of stress relief annealing temperature and atmosphere on the magnetic properties of silicon steel

International Nuclear Information System (INIS)

Paolinelli, Sebastiao C.; Cunha, Marco A. da

2006-01-01

Fully processed non-oriented silicon steel samples 0.50 mm thick were sheared and submitted to stress relief annealing under different conditions of temperature and atmosphere to investigate the effect of this treatment on the recovery of magnetic properties. Two different compositions were used, with different Si and Al contents. Temperature was varied in the range of 600-900 deg. C and four atmospheres were used: N 2 and N 2 +10%H 2 combined with dew points of -10 and 15 deg. C. The results showed that annealing atmosphere has very important effect on the magnetic properties and that the beneficial effect of stress relief annealing can be overcome by the detrimental effect of the atmosphere under certain conditions, due to oxidation and nitration

Test plan for long-term, low-temperature oxidation of spent fuel, Series 1

International Nuclear Information System (INIS)

Einziger, R.E.

1986-06-01

Preliminary studies indicated the need for more spent fuel oxidation data in order to determine the probable behavior of spent fuel in a tuff repository. Long-term, low-temperature testing was recommended in a comprehensive technical approach to: (1) confirm the findings of the short-term thermogravimetric analyses scoping experiments; (2) evaluate the effects of variables such as burnup, atmospheric moisture and fuel type on the oxidation rate; and (3) extend the oxidation data base ot representative repository temperatures and better define the temperature dependence of the operative oxidation mechanisms. This document presents the Series 1 test plan to study, on a large number of samples, the effects of atmospheric moisture and temperature on oxidation rate and phase formation. Tests will run for up to two years, use characterized fragmented, and pulverized fuel samples, cover a temperature range of 110 0 C to 175 0 C and be conducted with an atmospheric moisture content rangeing from 0 C to approx. 80 0 C dew point. After testing, the samples will be examined and made available for leaching testing

A thermal conductivity model for nanofluids including effect of the temperature-dependent interfacial layer

International Nuclear Information System (INIS)

Sitprasert, Chatcharin; Dechaumphai, Pramote; Juntasaro, Varangrat

2009-01-01

The interfacial layer of nanoparticles has been recently shown to have an effect on the thermal conductivity of nanofluids. There is, however, still no thermal conductivity model that includes the effects of temperature and nanoparticle size variations on the thickness and consequently on the thermal conductivity of the interfacial layer. In the present work, the stationary model developed by Leong et al. (J Nanopart Res 8:245-254, 2006) is initially modified to include the thermal dispersion effect due to the Brownian motion of nanoparticles. This model is called the 'Leong et al.'s dynamic model'. However, the Leong et al.'s dynamic model over-predicts the thermal conductivity of nanofluids in the case of the flowing fluid. This suggests that the enhancement in the thermal conductivity of the flowing nanofluids due to the increase in temperature does not come from the thermal dispersion effect. It is more likely that the enhancement in heat transfer of the flowing nanofluids comes from the temperature-dependent interfacial layer effect. Therefore, the Leong et al.'s stationary model is again modified to include the effect of temperature variation on the thermal conductivity of the interfacial layer for different sizes of nanoparticles. This present model is then evaluated and compared with the other thermal conductivity models for the turbulent convective heat transfer in nanofluids along a uniformly heated tube. The results show that the present model is more general than the other models in the sense that it can predict both the temperature and the volume fraction dependence of the thermal conductivity of nanofluids for both non-flowing and flowing fluids. Also, it is found to be more accurate than the other models due to the inclusion of the effect of the temperature-dependent interfacial layer. In conclusion, the present model can accurately predict the changes in thermal conductivity of nanofluids due to the changes in volume fraction and temperature for

Extreme precipitation response to climate perturbations in an atmospheric mesoscale model

International Nuclear Information System (INIS)

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. (paper)

Methods for the analysis of SO/sub 2/, SO/sub 3/ and H/sub 2/S in flue gas and the calculation of the acid dew point

Energy Technology Data Exchange (ETDEWEB)

Albertyn, C.H.

1986-02-01

Methods are given for the analysis of SO/sub 2/, SO/sub 3/, and H/sub 2/S in flue gas. Two methods are described for the determination of SO/sub 2/. The method to be used depends on whether or not H/sub 2/S is present in the gas stream. An equation for the calculation of acid dew point is given as well.

Bonding evolution with sintering temperature in low alloyed steels with chromium

Directory of Open Access Journals (Sweden)

Fuentes-Pacheco L.

2009-01-01

Full Text Available At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.

Increasing the efficiency of heating systems by reducing the flue gas temperature below the dew point

Energy Technology Data Exchange (ETDEWEB)

Kremer, H.

1981-06-01

This paper deals with the fundamentals and technical possibilities of increasing the combustion efficiency of gas-fired heating units for domestic heating by cooling the flue gases below their water vapor saturation temperature. The improvement of the efficiency can be more than 15% in comparison even to modern warm water heating boilers. Important however is the availability of cooling fluids of sufficiently low temperatures which could be recirculated heating water, freshwater and air. Different possible applications of this method are discussed in detail.

Hygromorphic Scales for Use in Water from Morning Dew and Elementary Model of Hydrogel Expansion Properties

Science.gov (United States)

Margolis, Nate

Secure access to water is a growing problem in the world today. Millions of people do not have contact with fresh or clean water for drinking. Consuming dirty water leads to many illnesses and deaths every year. When water is scarce people are less likely to follow basic hygiene which also adds to the problem of sickness from water. Currently most of the population gets their water from run-off such as rivers, lakes and other fresh water bodies. Aquafers can also provide water, however, once they do not replenish themselves so once they are empty they will no longer provide a fresh water source. This is a serious problem because the population has grown to 7 billion people and only 2% of the world's water is fresh water. Of this, most the fresh water is locked in the polar ice caps. This leaves only .77% of the available fresh water accessible for human use. While wealthy countries may not feel this burden due to their infrastructure. Impoverish countries will feel the full burden of a lack of water. This has led to a growing number of water conflicts over the years some of which have resulted in human deaths. There are several ways that people can collect water from the atmosphere such as collecting rain water or using a solar still to evaporate water out of an undrinkable source. In parts of the world where fog is prevalent, meshes have been used to collect the moisture from the air. However, these systems only work where the environment allows for it. In some places in the world, the only amount of water may come from morning dew. Certain places receive more water from morning dew than they do from annual precipitation. By studying nature, a novel water collection device was developed, tested and modeled. The model is compared to the test data to see the ways in which the device can be optimized. This could be used to help alleviate the growing problems of water shortages in specific parts of the world. The model and device design shows promising data but still

Filter for underground mining for suction of preferably full cut and part cut machines, to be provided with preheated air, to avoid dropping below the dew point

Energy Technology Data Exchange (ETDEWEB)

Hoelter, H.

1976-10-28

Particularly when cutting hard rock, the cutting room to be provided with suction is wetted with water from nozzles, which, when sucking out air containing dust with high humidity leads to encrustation in the filter cloth. In order to avoid this, it is proposed that the air should be heated, using heat from the motor driving the ventilator, so that one avoids dropping below the dew point in the filter.

Transient performance of integrated SOFC system including spatial temperature control

OpenAIRE

Mueller, F; Fardadi, M; Shaffer, B; Brouwer, J; Jabbari, F

2010-01-01

Spatial temperature feedback control has been developed for a simulated integrated non-pressurized simple cycle solid oxide fuel cell (SOFC) system. The fuel cell spatial temperature feedback controller is based on (1) feed-forward set-points that minimize temperature variation in the fuel cell electrode-electrolyte solid temperature profile for the system operating power range, and (2) decentralized proportional-integral based feedback to maintain the fuel cell spatial temperature profile du...

Humidity measurement using alpha-ray and beta-ray

International Nuclear Information System (INIS)

Matsumoto, Shigeaki; Kobayashi, Hisanobu

1981-01-01

Two new hygrometers using radioisotopes were proposed, and the results of tests are described. The one is a dew-point hygrometer utilizing the backscattering phenomena of beta-ray by dew, and the other is a hygrometer by measuring the variation of ionization current by alpha ray due to humidity. The backscattering of beta-ray depends on the atomic number of scatters and the energy of beta-ray. Therefore, the backscattering from dew on a gold plate is different from that from the gold itself. The temperature dependence of the backscattering intensity was measured with a GM counter. Decrease of the intensity was seen at the dew point. A control circuit was designed to measure the dew point automatically. The error of the measurement was within 1 degree C. An alpha-ray ionization hygrometer was constructed. The dependence of ionization current on humidity was measured with an operational amplifier. The resolution of humidity measurement was within 5 percent. (Kato, T.)

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

Science.gov (United States)

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.

Joining and fabrication techniques for high temperature structures including the first wall in fusion reactor

International Nuclear Information System (INIS)

Lee, Ho Jin; Lee, B. S.; Kim, K. B.

2003-09-01

The materials for PFC's (Plasma Facing Components) in a fusion reactor are severely irradiated with fusion products in facing the high temperature plasma during the operation. The refractory materials can be maintained their excellent properties in severe operating condition by lowering surface temperature by bonding them to the high thermal conducting materials of heat sink. Hence, the joining and bonding techniques between dissimilar materials is considered to be important in case of the fusion reactor or nuclear reactor which is operated at high temperature. The first wall in the fusion reactor is heated to approximately 1000 .deg. C and irradiated severely by the plasma. In ITER, beryllium is expected as the primary armour candidate for the PFC's; other candidates including W, Mo, SiC, B4C, C/C and Si 3 N 4 . Since the heat affected zones in the PFC's processed by conventional welding are reported to have embrittlement and degradation in the sever operation condition, both brazing and diffusion bonding are being considered as prime candidates for the joining technique. In this report, both the materials including ceramics and the fabrication techniques including joining technique between dissimilar materials for PFC's are described. The described joining technique between the refractory materials and the dissimilar materials may be applicable for the fusion reactor and Generation-4 future nuclear reactor which are operated at high temperature and high irradiation

Estimativa da duração do período de molhamento por orvalho em um ecossistema cacau Estimate of the duration of the wetness period by dew in a cocoa ecosystem

Directory of Open Access Journals (Sweden)

Hermes A. de Almeida

2009-12-01

Full Text Available O objetivo deste trabalho foi estimar a duração do período de molhamento por orvalho (DPM, entre 18 e 06 h, utilizando-se dois modelos empíricos: a o do número de horas com umidade relativa > a 97% (NHUR > 97% e b o da depressão do ponto de orvalho The objective of this study was to estimate the duration of wetness by dew (DWW, from 18 to 06 h, using two empirical models: a number of hours with relative air humidity > 97% (NHUR > 97% and b depression of the dew point 61%, although the percentage for winter and summer months was 80.8 and 15.8% respectively. The high statistical indexes observed here show the viability of the models for estimating, with high precision, the DWW in a cocoa ecosystem. The models are of easy application and operation, dispensing the utilization of sensors and of more complex methods. Howerer, they still need some adjustments to be used for other crops and conditions.

Searching for the best modeling specification for assessing the effects of temperature and humidity on health: a time series analysis in three European cities.

Science.gov (United States)

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.

The Mollier diagram in theory and practice. Part 2. Evaporative indirect static dew point cooling and the Mollier diagram; Het Mollierdiagram in theorie en praktijk. Deel 2. Verdampingskoeling verklaard vanuit het Mollierdiagram

Energy Technology Data Exchange (ETDEWEB)

Uges, P.G.H. (ed.) [StatiqCooling, Deventer (Netherlands)

2007-02-15

The use of direct and indirect adiabatic cooling, and recently in particular indirect diabatic cooling (dew point cooling) require knowledge of the Mollier diagram. [Dutch] Het gebruik van direct en indirect werkende adiabatische koeling en recentlijk vooral de indirect werkende systemen zoals diabatische koeling (dauwpuntkoeling, al of niet uitgevoerd als statische koeling) vragen om kennis van het Mollierdiagram.

The Climatology Module CLIMAT

National Research Council Canada - National Science Library

Avara, Elton

1998-01-01

... (temperature, dew point temperature, absolute humidity, relative humidity, horizontal visibility, sea level pressure, wind speed, wind direction, cloudbase height, cloud cover, and Pasquill stability category...

Digital Earth Watch (DEW): How Mobile Apps Are Paving The Way Towards A Federated Web-Services Architecture For Citizen Science

Science.gov (United States)

Carrera, F.; Schloss, A. L.; Guerin, S.; Beaudry, J.; Pickle, J.

2011-12-01

Dozens of web-based initiatives allow citizens to provide information to programs that monitor the health of our environment. A concerned citizen can participate on-line as a weather "spotter", provide important phenological information to national databases, update bird counts in the area, or record the freezing of ponds, and much more. Many of these programs are developing mobile apps as companion tools to their web sites. Our group was involved in the development of one such companion app as an adjunct to the Picture Post project web site. Digital Earth Watch (DEW) and the Picture Post network support environmental monitoring through repeat digital photography and satellite imagery. A Picture Post is an eight-sided platform on a stand-alone post for taking a panoramic series of photographs. By taking pictures on a regular basis at Picture Post sites and by sharing these pictures on the program's web site (housed at the University of New Hampshire), citizen scientists are creating a photographic library of change-over-time in their local area and contributing to national monitoring programs. Our DEW Android application simplifies participation by allowing users to upload pictures instantly from their smart phone. The app also removes the constraint of the physical picture post, by allowing users to create a virtual post anywhere in the world. Posts have been set up to monitor trails, forests, water, wetlands, gardens and landscapes. The app uses the phone's GPS to position the virtual post in its geographic location and guides the user through the orientations thanks to the internal accelerometers and compass. To aid in the before-and-after comparison of images taken from the same orientation, the DEW app displays an "onionskin" of the prior image overlayed onto the camera viewfinder. With the transparent onionskin as a guide, the user can align the images more accurately, thus allowing differences between pictures to be detectable and measurable. The app

Joining and fabrication techniques for high temperature structures including the first wall in fusion reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Ho Jin; Lee, B. S.; Kim, K. B

2003-09-01

The materials for PFC's (Plasma Facing Components) in a fusion reactor are severely irradiated with fusion products in facing the high temperature plasma during the operation. The refractory materials can be maintained their excellent properties in severe operating condition by lowering surface temperature by bonding them to the high thermal conducting materials of heat sink. Hence, the joining and bonding techniques between dissimilar materials is considered to be important in case of the fusion reactor or nuclear reactor which is operated at high temperature. The first wall in the fusion reactor is heated to approximately 1000 .deg. C and irradiated severely by the plasma. In ITER, beryllium is expected as the primary armour candidate for the PFC's; other candidates including W, Mo, SiC, B4C, C/C and Si{sub 3}N{sub 4}. Since the heat affected zones in the PFC's processed by conventional welding are reported to have embrittlement and degradation in the sever operation condition, both brazing and diffusion bonding are being considered as prime candidates for the joining technique. In this report, both the materials including ceramics and the fabrication techniques including joining technique between dissimilar materials for PFC's are described. The described joining technique between the refractory materials and the dissimilar materials may be applicable for the fusion reactor and Generation-4 future nuclear reactor which are operated at high temperature and high irradiation.

Some problems on materials tests in high temperature hydrogen base gas mixture

International Nuclear Information System (INIS)

Shikama, Tatsuo; Tanabe, Tatsuhiko; Fujitsuka, Masakazu; Yoshida, Heitaro; Watanabe, Ryoji

1980-01-01

Some problems have been examined on materials tests (creep rupture tests and corrosion tests) in high temperature mixture gas of hydrogen (80%H 2 + 15%CO + 5%CO 2 ) simulating the reducing gas for direct steel making. H 2 , CO, CO 2 and CH 4 in the reducing gas interact with each other at elevated temperature and produce water vapor (H 2 O) and carbon (soot). Carbon deposited on the walls of retorts and the water condensed at pipings of the lower temperature gas outlet causes blocking of gas flow. The gas reactions have been found to be catalyzed by the retort walls, and appropriate selection of the materials for retorts has been found to mitigate the problems caused by water condensation and carbon deposition. Quartz has been recognized to be one of the most promising materials for minimizing the gas reactions. And ceramic coating, namely, BN (born nitride) on the heat resistant superalloy, MO-RE II, has reduced the amounts of water vapor and deposited carbon (sooting) produced by gas reactions and has kept dew points of outlet gas below room temperature. The well known emf (thermo-electromotive force) deterioration of Alumel-Chromel thermocouples in the reducing gases at elevated temperatures has been also found to be prevented by the ceramic (BN) coating. (author)

Active condensation of water by plants

Directory of Open Access Journals (Sweden)

Prokhorov Alexey Anatolievich

2013-10-01

Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.

Critical point analysis of phase envelope diagram

International Nuclear Information System (INIS)

Soetikno, Darmadi; Siagian, Ucok W. R.; Kusdiantara, Rudy; Puspita, Dila; Sidarto, Kuntjoro A.; Soewono, Edy; Gunawan, Agus Y.

2014-01-01

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, 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

Critical point analysis of phase envelope diagram

Energy Technology Data Exchange (ETDEWEB)

Soetikno, Darmadi; Siagian, Ucok W. R. [Department of Petroleum Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Kusdiantara, Rudy, E-mail: rkusdiantara@s.itb.ac.id; Puspita, Dila, E-mail: rkusdiantara@s.itb.ac.id; Sidarto, Kuntjoro A., E-mail: rkusdiantara@s.itb.ac.id; Soewono, Edy; Gunawan, Agus Y. [Department of Mathematics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

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, 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.

MHD model including small-scale perturbations in a plasma with temperature variations

International Nuclear Information System (INIS)

Kuvshinov, B.N.; Mikhailovskii, A.B.

1996-01-01

The possibility is studied of using a hydrodynamic model to describe a magnetized plasma with density and temperature variations on scales that are arbitrary with respect to the ion Larmor radius. It is shown that the inertial component of the transverse ion thermal flux should be taken into account. This component is found from the collisionless kinetic equation. It can also be obtained from the equations of the Grad type. A set of two-dimensional hydrodynamic equations for ions is obtained with this component taken into account. These equations are used to derive model hydrodynamic expressions for the density and temperature variations. It is shown that, for large-scale perturbations (when the wavelengths are longer than the ion Larmor radius), the expressions derived coincide with the corresponding kinetic expressions and, for perturbations on sub-Larmor scales (when the wavelengths are shorter than the Larmor radius), they agree qualitatively. Hydrodynamic dispersion relations are derived for several types of drift waves with arbitrary wavenumbers. The range of applicability of the MHD model is determined from a comparison of these dispersion relations with the kinetic ones. It is noted that, on the basis of results obtained, drift effects can be included in numerical MHD codes for studying plasma instabilities in high-temperature regimes in tokamaks

Development of a Weather Running Estimate-Nowcast Capability for the U.S. Army IMETS

National Research Council Canada - National Science Library

Henmi, Teizi; Dumais, Robert; Okrasinski, Richard

2005-01-01

...) forecast, surface, and upper-air sounding data, are used for the computation. Three-dimensional distributions of temperature, dew-point temperature, and horizontal wind vector components can be forecasted...

Summary of PWR leak detection studies

International Nuclear Information System (INIS)

Cho, J.H.; Elia, F.A. Jr.

1986-01-01

Thermal-hydraulic analysis can be used to determine the location and magnitude of leaks inside and location of leaks outside a pressurized water reactor (PWR) containment as required by plant technical specifications. The major advantage of this detection method is that it minimizes radiation exposure of maintenance personnel because most of the leak detection process is performed from the control room outside containment. Plant-specific analyses are utilized to predict change in parameters such as local dew point temperature, relative humidity, dry bulb temperature, and flow rate to sump for various leak rates and enthalpies. These parameter responses are then programmed into the plant computer and instrumentation is provided for area monitoring. The actual inputs are continuously monitored and compared to the predicted plant responses to identify the leak location and quantify the leak. This study concludes that a system that monitors dew point (or relative humidity) and dry bulb temperature changes together with the flow rate to the sump will provide the capability to both locate and quantify a leak inside a containment, while a system that monitors dew point temperature (or relative humidity) changes will provide the capability to locate a leak outside a containment

Modeling of the Direct Current Generator Including the Magnetic Saturation and Temperature Effects

Directory of Open Access Journals (Sweden)

Alfonso J. Mercado-Samur

2013-11-01

Full Text Available In this paper the inclusion of temperature effect on the field resistance on the direct current generator model DC1A, which is valid to stability studies is proposed. First, the linear generator model is presented, after the effect of magnetic saturation and the change in the resistance value due to temperature produced by the field current are included. The comparison of experimental results and model simulations to validate the model is used. A direct current generator model which is a better representation of the generator is obtained. Visual comparison between simulations and experimental results shows the success of the proposed model, because it presents the lowest error of the compared models. The accuracy of the proposed model is observed via Modified Normalized Sum of Squared Errors index equal to 3.8979%.

Methods and strategy for modeling daily global solar radiation with measured meteorological data - A case study in Nanchang station, China

International Nuclear Information System (INIS)

Wu, Guofeng; Liu, Yaolin; Wang, Tiejun

2007-01-01

Solar radiation is a primary driver for many physical, chemical and biological processes on the earth's surface, and complete and accurate solar radiation data at a specific region are quite indispensable to the solar energy related researches. This study, with Nanchang station, China, as a case study, aimed to calibrate existing models and develop new models for estimating missing global solar radiation data using commonly measured meteorological data and to propose a strategy for selecting the optimal models under different situations of available meteorological data. Using daily global radiation, sunshine hours, temperature, total precipitation and dew point data covering the years from 1994 to 2005, we calibrated or developed and evaluated seven existing models and two new models. Validation criteria included intercept, slope, coefficient of determination, mean bias error and root mean square error. The best result (R 2 = 0.93) was derived from Chen model 2, which uses sunshine hours and temperature as predictors. The Bahel model, which only uses sunshine hours, was almost as good, explaining 92% of the solar radiation variance. Temperature based models (Bristow and Campbell, Allen, Hargreaves and Chen 1 models) provided less accurate results, of which the best one (R 2 = 0.69) is the Bristow and Campbell model. The temperature based models were improved by adding other variables (daily mean total precipitation and mean dew point). Two such models could explain 77% (Wu model 1) and 80% (Wu model 2) of the solar radiation variance. We, thus, propose a strategy for selecting an optimal method for calculating missing daily values of global solar radiation: (1) when sunshine hour and temperature data are available, use Chen model 2; (2) when only sunshine hour data are available, use Bahel model; (3) when temperature, total precipitation and dew point data are available but not sunshine hours, use Wu model 2; (4) when only temperature and total precipitation are

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

Science.gov (United States)

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).

Desiccant Dewpoint Cooling System Independent of External Water Sources

DEFF Research Database (Denmark)

Bellemo, Lorenzo; Elmegaard, Brian; Markussen, Wiebke B.

2015-01-01

the air that regenerates the desiccant dehumidifier, and using it for running the evaporative coolers in the system. A closed regeneration circuit is used for maximizing the amount of condensed water. This solution is applied to a system with a desiccant wheel dehumidifier and a dew point cooler, termed...... desiccant dew-point cooling system, for demonstrating its function and applicability. Simulations are carried out for varying outdoor conditions under constant supply conditions. The results show that the system is independent of external water supply for the majority of simulated conditions. In comparison...... to the desiccant dew-point system without water recovery, the required regeneration temperature increases and the system thermal efficiency decreases....

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

Science.gov (United States)

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.

The contact-temperature ignition (CTI) criteria for propagating chemical reactions including the effect of moisture and application to Hanford waste

International Nuclear Information System (INIS)

Cash, R.J.

1995-01-01

To assure the continued absence of uncontrolled condensed-phase chemical reactions in connection with the Hanford waste materials, efforts have been underway including both theoretical and experimental investigations to clarify the requirements for such reactions. This document defines the differences and requirements for homogeneous runaway and propagating chemical reactions incuding a discussion of general contact-temperature ignition (CTI) condition for propagating reactions that include the effect of moisture. The CTI condition implies that the contact temperature or interface temperature between reacted and unreacted materials must exceed the ignition temperature and is compared to experimental data including both synthetic ferrocyanide and surrogate organic materials. In all cases, the occurrences of ignition accompanied by self-propagating reactions are consistent with the theoretical anticipations of the CTI condition

Statistical Studies of Mesoscale Forecast Models MM5 and WRF

National Research Council Canada - National Science Library

Henmi, Teizi

2004-01-01

... models were carried out and the results were compared with surface observation data. Both models tended to overforecast temperature and dew-point temperature, although the correlation coefficients between forecast and observations were fairly high...

Modeling of Temperature-Dependent Noise in Silicon Nanowire FETs including Self-Heating Effects

Directory of Open Access Journals (Sweden)

P. Anandan

2014-01-01

Full Text Available Silicon nanowires are leading the CMOS era towards the downsizing limit and its nature will be effectively suppress the short channel effects. Accurate modeling of thermal noise in nanowires is crucial for RF applications of nano-CMOS emerging technologies. In this work, a perfect temperature-dependent model for silicon nanowires including the self-heating effects has been derived and its effects on device parameters have been observed. The power spectral density as a function of thermal resistance shows significant improvement as the channel length decreases. The effects of thermal noise including self-heating of the device are explored. Moreover, significant reduction in noise with respect to channel thermal resistance, gate length, and biasing is analyzed.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

A temperature dependent cyclic plasticity model for hot work tool steel including particle coarsening

Science.gov (United States)

Jilg, Andreas; Seifert, Thomas

2018-05-01

Hot work tools are subjected to complex thermal and mechanical loads during hot forming processes. Locally, the stresses can exceed the material's yield strength in highly loaded areas as e.g. in small radii in die cavities. To sustain the high loads, the hot forming tools are typically made of martensitic hot work steels. While temperatures for annealing of the tool steels usually lie in the range between 400 and 600 °C, the steels may experience even higher temperatures during hot forming, resulting in softening of the material due to coarsening of strengthening particles. In this paper, a temperature dependent cyclic plasticity model for the martensitic hot work tool steel 1.2367 (X38CrMoV5-3) is presented that includes softening due to particle coarsening and that can be applied in finite-element calculations to assess the effect of softening on the thermomechanical fatigue life of hot work tools. To this end, a kinetic model for the evolution of the mean size of secondary carbides based on Ostwald ripening is coupled with a cyclic plasticity model with kinematic hardening. Mechanism-based relations are developed to describe the dependency of the mechanical properties on carbide size and temperature. The material properties of the mechanical and kinetic model are determined on the basis of tempering hardness curves as well as monotonic and cyclic tests.

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

Science.gov (United States)

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.

Leaf wetness distribution within a potato crop

Science.gov (United States)

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.

Estimation of daily solar radiation from routinely observed meteorological data in Chongqing, China

International Nuclear Information System (INIS)

Li Maofen; Liu Hongbin; Guo Pengtao; Wu Wei

2010-01-01

Solar radiation is a very important and major variable in crop simulation models. However, it is measured at a very limited number of meteorological stations worldwide. Models were developed to estimate daily solar radiation in Chongqing, one of the most important agricultural areas in China. Several routinely observed meteorological variables including daily maximum and minimum temperatures, daily mean dew point temperature, fog and rainfall had been obtained, investigated and analyzed from 1986 to 2000 for Chongqing. The monthly mean daily solar radiation at this location ranged from a maximum of 15.082 MJ m -2 day -1 in August and a minimum of 3.042 MJ m -2 day -1 in December. A newly developed model that included all selected variables proved the best method with a RMSE value of 2.522 MJ m -2 day -1 . The best performed models for different seasons were further evaluated according to divide-and-conquer principle. The model using all selected variables provided the best estimates of daily solar radiation in winter and autumn with RMSE values of 1.491 and 2.037 MJ m -2 day -1 , respectively. The method involving temperatures and rainfall information could be used to estimate daily solar radiation in summer with a RMSE value of 3.163 MJ m -2 day -1 . The model using temperature, rainfall and dew point data performed better than other models in spring with a RMSE value of 2.910 MJ m -2 day -1 .

The meteorological measurement system of the Karlsruhe Nuclear Research Center

International Nuclear Information System (INIS)

Dilger, H.

1976-08-01

The system mainly serves to record the parameters which are important for the diffusion of offgas plume. The system includes 47 instruments in total which are used to measure the wind velocity, the wind direction, the wind vector, the temperature, the dew point, the solar and heat radiation, the precipitations and the atmospheric pressure, most of them mounted at the 200 m high meteorological tower. (orig./HP) [de

Theoretical and testing performance of an innovative indirect evaporative chiller

Energy Technology Data Exchange (ETDEWEB)

Jiang, Yi; Xie, Xiaoyun [Department of Building Science and Technology, Tsinghua University, Beijing (China)

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 indirect 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

Study on the conversion of H2 and CO from the helium carrier gas of high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Liao Cuiping; Zheng Zhenhong; Shi Fuen

1995-01-01

The conversions of hydrogen and carbon monoxide into water vapor and carbon dioxide on CuO-ZnO-Al 2 O 3 catalyst are studied. The effects of different temperature, system atmospheric pressure, impurity gas concentration, flow and dew point on properties of cupric oxide bed are investigated. The conversion characteristics curves of H 2 and CO are given. Experimental data of conversion capacity, action period and conversion efficiency of CuO-ZnO-Al 2 O 3 are obtained and the optimal parameters are determined. The results show that the concentration of H 2 and CO of the effluent gas after purification can reach below 2 x 10 -6 , respectively. So it can meet the demands of high temperature gas-cooled reactor and also provide optimal design parameters and reliable data for conversion of H 2 and CO on CuO-ZnO-Al 2 O 3 catalyst

ESTUDIO DE LA INTERRELACION ENTRE LA COMPOSICION Y QUIMICA DEL ROCIO CON LOS PROCESOS FOTOQUIMICOS ATMOSFERICOS.

OpenAIRE

Maria Angelica Rubio Campos; Ernesto Vicente Gramsch Labra; Eduardo Alejandro Lissi Gervaso; Maximiliano Araya Orellana; Marcela Shielien Cadiz Gin; Augusta Victoria Caroca Muñoz; Irene Eugenia Fuenzalida Farias; Cesar Antonio Gonzales Fernandez; Maria Jose Guerrero Duarte; Jimena Valentina Maira Solis; Elizabeth Salinas Donaire; Claudia Vega Vega; Natalia Zamorano Carrasco

2004-01-01

STUDY ON THE INTERRELATION BETWEEN COMPOSITION AND CHEMISTRY OF DEW AND ATMOSPHERIC PHOTOCHEMICAL PROCESSES The general objective of this project was to evaluate the impact of the different sources of radicals generated in the atmosphere of the city of Santiago, thus getting to know their relation to the chemical composition of dew, fog and rain. The hypothesis proposed in this study is that dews can include substances of photochemical origin, which might lead to the generation of smog...

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

Science.gov (United States)

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 ...

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Improvement of thermal exchange between feedstock and effluent in a hydrocarbon processing unit under hydrogen atmosphere by partial recycling of the product

Energy Technology Data Exchange (ETDEWEB)

Orieux, A.

1990-01-19

Heat exchange is improved in light naphta hydroisomerization and catalytic reforming by recirculation of a part of the product in the thermal exchange zone at a temperature higher than the dew point of the effluent under hydrogen atmosphere and preferentially as a temperature lower than the temperature of the recycled product.

Comparing daily temperature averaging methods: the role of surface and atmosphere variables in determining spatial and seasonal variability

Science.gov (United States)

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.

75 FR 2860 - Clean Water Act Section 303(d): Call for Data for the Illinois River Watershed in Oklahoma and...

Science.gov (United States)

2010-01-19

... movement, solar radiation, dew-point temperature, and cloud cover. Daily data for the 1980-2010 time... lengths and slopes, cross-sections and geometry, bed composition (sediment particle sizes, nutrients...

Conversion of medium and low temperature heat to power

Science.gov (United States)

Fischer, Johann; Wendland, Martin; Lai, Ngoc Anh

2013-04-01

improvement. Presently, the best feasible systems seem to be ORC cycles using WF with a nearly vertical dew line in the T,s-diagram as HFO-1234yf, n-butane or cyclopentane and upper pressures close below or above (sORC) the critical pressure. Finally, we will consider the above cycles also with mixtures as WF including the Kalina cycle and coupled processes like cascade or multistage processes. [1] B Saleh, G Koglbauer, M Wendland, J Fischer, Working fluids for low temperature ORC-processes, Energy 32, 1210-21 (2007). [2] N A Lai, J Fischer, Efficiencies of Power Flash Cycles, Energy 44, 1017-27 (2012). [3] T Ho, S S Mao, R Greif, Comparison of the Organic Flash Cycle (OFC) to other advanced vapor cycles for intermediate and high temperature waste heat reclamation and solar thermal energy, Energy 42, 213-23 (2012).

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Modelling of temporal and spatial evolution of sulphur oxides and sulphuric acid under large, two-stroke marine engine-like conditions using integrated CFD-chemical kinetics

DEFF Research Database (Denmark)

Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore

2017-01-01

that the flameimpinges at the cylinder liner near top dead centre. The gas is cooled rapidly by the wall temperatureand H2SO4 is produced in the region where the local temperature is less than 600 K. Based on the fluegas correlation, the acid dew point temperature is higher than the wall temperature, suggesting...

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

Science.gov (United States)

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.

Moisture content of cereals at harvesting time by comparing microclimate values and standard weather data.

NARCIS (Netherlands)

Atzema, A.J.

1993-01-01

The moisture content of wheat and barley together with the weather elements were measured at 3 different experimental sites in the Netherlands in 1990-91. The difference in the dew point temperature in the screen[house] and in the field was small. However, the differences between air temperature in

Uncertainty Evaluation of the New Setup for Measurement of Water-Vapor Permeation Rate by a Dew-Point Sensor

Science.gov (United States)

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).

Dual-pressure vaporization Kalina cycle for cascade reclaiming heat resource for power generation

International Nuclear Information System (INIS)

Guo, Zhanwei; Zhang, Zhi; Chen, Yaping; Wu, Jiafeng; Dong, Cong

2015-01-01

Graphical abstract: Schematic of the dual-pressure evaporation Kalina cycle. - Highlights: • Dual-pressure vaporization Kalina cycle for high-grade heat resource is investigated. • It is designed with 2nd evaporation branch for cascade utilization of heat resource. • Work and basic concentrations, dew point temperature of evaporation are optimized. • Power recovery efficiency of proposed cycle is 17% higher than that of Kalina cycle. • Dual-p vaporization Kalina cycle fits reclaiming heat resource higher than 350 °C. - Abstract: To further improve the cycle efficiency with the heat transfer curves between higher than 350 °C heat resource and the evaporating working medium of the Kalina cycle and to reduce the exhaust temperature of heat resource, the dual-pressure vaporization Kalina cycle for cascade utilization of high-to-mid grade heat resource is proposed. The optimization was conducted for parameters in this modified Kalina cycle such as concentrations of work solution and basic solution, evaporation dew point temperature. Under the conditions of inlet temperatures of heat resource and cooling water of respectively 400 °C and 25 °C and the constraints of proper heat transfer pinch point temperature differences, the maximum evaporation pressure not exceeds 20 MPa, the vapour quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat resource is not lower than 90 °C, the optimum parameters are obtained that the work and basic concentrations are 0.45 and 0.272 respectively, the dew point temperature of evaporation is 300 °C, and the corresponding power recovery efficiency of the dual-pressure vaporization Kalina cycle reaches 27%, which is 17% higher than that of the Kalina cycle with optimum parameters.

EDITORIAL: Humidity sensors Humidity sensors

Science.gov (United States)

Regtien, Paul P. L.

2012-01-01

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

Un versión española de la Escala de Estrategias de Afrontamiento de Maestros ante Estresores Laborales (Dewe, 1985

Directory of Open Access Journals (Sweden)

T. LOZANO-YAGÜE

2003-01-01

Full Text Available El objetivo propuesto fue adaptar la escala de Estrategias de Afrontamiento utilizadas por los Maestros ante Estresores Laborales (Dewe, 1985 a los docentes no universitarios españoles. Con tal propósito, la versión resultante del proceso de traducción-retrotraducción fue autocumplimentada, junto a otras escalas de referencia, por 172 docentes no universitarios dependientes del Ministerio de Educación y Cultura (M.E.C., analizándose posteriormente su fiabilidad (análisis factorial y análisis de la consistencia interna y validez (matriz de correlaciones. La versión obtenida resultó, a juicio de los participantes en la traducciónretrotraducción, equivalente conceptual, técnica y semánticamente con la versión original. A partir de dicha versión se consiguió una escala reducida compuesta de cinco factores y 27 variables, con unas adecuadas validez de contenido y de constructo (validez convergente y discriminante y fiabilidad (coeficiente alfa de Cronbach, ¿>0,7, para su aplicación en nuestro medio.

Diagnostic Measurement at Chimney Operation

Directory of Open Access Journals (Sweden)

Radim JANALÍK

2012-06-01

Full Text Available The article is focused on the solution of heat penetration through the body of a chimney based on the measurements of output temperatures of flue gases coming out of a chimney and their dew point, in order to determine the minimum flue gas temperature at the bag filter inlet.

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

Science.gov (United States)

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

Modeling daily soil temperature over diverse climate conditions in Iran—a comparison of multiple linear regression and support vector regression techniques

Science.gov (United States)

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.

Dew Point Temperature Affects Ascospore Release of Allergenic Genus Leptosphaeria

OpenAIRE

Sadyś, M.; Kaczmarek, J.; Grinn-Gofron, A.; Rodinkova, V.; Prikhodko, A.; Bilous, E.; Strzelczak, A.; Herbert, Rob; Jedryczka, M.

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...

estimation of precipitable water vapour in nigeria using surface

African Journals Online (AJOL)

USER

For the purpose of this work, Nigeria was divided into four climatic regions and for each region empirical models of the form PWV (T ) and PWV (RH) were found; where T was the surface dew- d d point temperature ... its effect on the atmospheric temperature and .... making contact with the coastal land, the clouds will then ...

40 CFR 92.110 - Weighing chamber and micro-balance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Weighing chamber and micro-balance. 92... Weighing chamber and micro-balance. (a) Ambient conditions—(1) Temperature. The temperature of the chamber... shall be 45±8 percent during all filter conditioning and weighing. The dew point shall be 6.4 to 12.4 °C...

The Phase Envelope of Multicomponent Mixtures in the Presence of a Capillary Pressure Difference

DEFF Research Database (Denmark)

Sandoval Lemus, Diego Rolando; Yan, Wei; Michelsen, Michael Locht

2016-01-01

for test mixtures with wide ranges of compositions at different capillary radii and vapor fractions. The calculation results show that the phase envelope changes everywhere except at the critical point. The bubble point and the lower branch of the dew point show a decrease in the saturation pressure......, whereas the upper branch of the dew point shows an increase. The cricondentherm is shifted to a higher temperature. We also presented a mathematical analysis of the phase envelope shift due to capillary pressure based on linear approximations. The resulting linear approximation equations can predict...... the magnitude of shift, and the approximation is close for the change in the bubble point pressure....

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

Science.gov (United States)

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.

Acoustic dew point and bubble point detector for gas condensates and reservoir fluids

Energy Technology Data Exchange (ETDEWEB)

Sivaraman, A.; Hu, Y.; Thomas, F. B.; Bennion, D. B.; Jamaluddin, A. K. M. [Hycal Energy Research Labs. Ltd., Calgary, AB (Canada)

1997-08-01

Detailed knowledge of bubblepoint and dewpoint pressures at reservoir temperature are crucial for natural gas processing, transportation, metering and utilization. This paper introduces a new acoustic dewpoint and bubblepoint detector that can be applied to a broad range of phase transitions, including very lean gas systems and opaque heavy oils. The system uses two acoustic transducers, one to stimulate and the other to detect normal mode vibrations of reservoir fluids in a small cylindrical resonator. The acoustic spectra are recorded at close intervals throughout the phase envelope, along with temperature, pressure and volume measurements, and the data is processed to obtain the specific condition of phase transition. Results of two systems, a binary mixture and live reservoir fluid, are presented. The detector system is claimed to be capable of operation in an isothermal mode with variable volume, and in a constant volume mode with variable temperatures. Interpretation of results is free of operator subjectivity; they show excellent agreement with results obtained by visual methods and equations of state calculations. 4 refs., 2 tabs., 4 figs.

Statistical Correction of Air Temperature Forecasts for City and Road Weather Applications

Science.gov (United States)

Mahura, Alexander; Petersen, Claus; Sass, Bent; Gilet, Nicolas

2014-05-01

that the CPU time required for the operational procedure is relatively short (less than 15 minutes including a large time spent for interpolation). These also showed that in order to start correction of forecasts there is no need to have a long-term pre-historical data (containing forecasts and observations) and, at least, a couple of weeks will be sufficient when a new observational station is included and added to the forecast point. Note for the road weather application, the operationalization of the statistical correction of the road surface temperature forecasts (for the RWM system daily hourly runs covering forecast length up to 5 hours ahead) for the Danish road network (for about 400 road stations) was also implemented, and it is running in a test mode since Sep 2013. The method can also be applied for correction of the dew point temperature and wind speed (as a part of observations/ forecasts at synoptical stations), where these both meteorological parameters are parts of the proposed system of equations. The evaluation of the method performance for improvement of the wind speed forecasts is planned as well, with considering possibilities for the wind direction improvements (which is more complex due to multi-modal types of such data distribution). The method worked for the entire domain of mainland Denmark (tested for 60 synoptical and 395 road stations), and hence, it can be also applied for any geographical point within this domain, as through interpolation to about 100 cities' locations (for Danish national byvejr forecasts). Moreover, we can assume that the same method can be used in other geographical areas. The evaluation for other domains (with a focus on Greenland and Nordic countries) is planned. In addition, a similar approach might be also tested for statistical correction of concentrations of chemical species, but such approach will require additional elaboration and evaluation.

Influence of Gas Atmosphere Dew Point on the Selective Oxidation and the Reactive Wetting During Hot Dip Galvanizing of CMnSi TRIP Steel

Science.gov (United States)

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.

Performance of operational radiosonde humidity sensors in direct comparison with a chilled mirror dew-point hygrometer and its climate implication

Science.gov (United States)

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.

The spatial extent of rainfall events and its relation to precipitation scaling

NARCIS (Netherlands)

Lochbihler, K.U.; Lenderink, Geert; Siebesma, A.P.

2017-01-01

Observations show that subdaily precipitation extremes increase with dew point temperature at a rate exceeding the Clausius-Clapeyron (CC) relation. The understanding of this so-called super CC scaling is still incomplete, and observations of convective cell properties could provide important

Summaries of reports of the 30. Conference on low-temperature physics. Pt. 1. Fundamental questions of superconductivity including HTSC

International Nuclear Information System (INIS)

1994-01-01

Thesis of reporsts of the 30th Conference on low-temperature physics are presented. Fundamental problems of superconductivity are discussed including HTSC in bulk crystals, in thin films of Josephson junctions, ceramics and heterostructures. Specific features of superconductor structure and magnetic properties and also different mechanisms of superconductivity are analyzed

Water condensation promotes fungal growth in ventilation ducts

Energy Technology Data Exchange (ETDEWEB)

Pasanen, P.; Pasanen, A.-L. (University of Kupopio, Department of Environmental Sciences, Kuopio (Finland)); Jantunen, M. (National Public Health Institute, Kuopio (Finland))

1993-01-01

In a subarctic climate the diurnal variation in temperature may cause water condensation in ducts placed in the unheated spaces of a building. In this study, germination time and sporulation of a fungus, Penicillium verrucosum, were studied on dusty, galvanized steel sheet under different moisture conditions at room temperature. The effect of condensed water in a supply air duct on spore amplification was studied in an experimental ventilation set-up. In the field, air temperatures and the dew point temperature of air in the duct were monitored continuously for a week. P. verrucosum germinated on steel surfaces during five-hour incubation of the surface under humid conditions, when the surface has been moist for half an hour, germ tubes appeared within 17 hours. During 24-hour incubation under moist conditions, P. verrucosum produced hyphae and spores. In the experimental set-up the airborne spore counts increased when the air passed through a water-condensing section of the duct. Penicillium was the most abundant fungus sporulated on the moist duct surface. In the field, during humid weather, the surface temperature on the air stream surface decreased to the dew point temperature of the air in the duct. thus water condensation in air ducts may promote fungal growth. (au)

Future PMP Estimation in Korea under AR5 RCP 8.5 climate change scenarios and its Changes Cause Analysis

Science.gov (United States)

Kim, S.; Lee, J.; Okjeong, L.; Bogyeong, C.; Park, M. W.

2015-12-01

In this presentation, Korea's probable maximum precipitations (PMPs) which reflects all of the storm data until recently are calculated, and are compared to the existing PMPs which were calculated at 2000. In Korea, abnormal weather phenomena such as typhoon Rusa and Maemi, and the extreme rainfall event occurred on the east coast of the northern region, that can have a significant impact on the PMP estimation, have frequently happened since 2000. After selecting 240 major storm events from 1973 to 2012, new PMPs are proposed with respect to storm areas (25, 100, 225, 400, 900, 2025, 4900, 10000 and 19600 km2) and storm durations (1, 2, 4, 6, 8, 12, 18, 24, 48 and 72 hours) using the Korea hydro-meteorological method. After estimating future PMPs using future rainfall and dew point temperature information under the Korea Meteorological Administration AR5 RCP 8.5, changes in the PMPs under climate change will be investigated by comparison with present and future PMPs. By separating the changes in PMPs under climate change into the changes caused by rainfall and dew point temperature, the relative impact of future rainfall and dew point temperature information under climate change on future PMPs is quantified. This research was supported by a grant 'Development of the Evaluation Technology for Complex Causes of Inundation Vulnerability and the Response Plans in Coastal Urban Areas for Adaptation to Climate Change' [MPSS-NH-2015-77] from the Natural Hazard Mitigation Research Group, Ministry of Public Safety and Security of Korea.

The effects of sea surface temperature gradients on surface turbulent fluxes

Science.gov (United States)

Steffen, John

A positive correlation between sea surface temperature (SST) and wind stress perturbation near strong SST gradients (DeltaSST) has been observed in different parts of the world ocean, such as the Gulf Stream in the North Atlantic and the Kuroshio Extension east of Japan. These changes in winds and SSTs can modify near-surface stability, surface stress, and latent and sensible heat fluxes. In general, these small scale processes are poorly modeled in Numerical Weather Prediction (NWP) and climate models. Failure to account for these air--sea interactions produces inaccurate values of turbulent fluxes, and therefore a misrepresentation of the energy, moisture, and momentum budgets. Our goal is to determine the change in these surface turbulent fluxes due to overlooking the correlated variability in winds, SSTs, and related variables. To model these air--sea interactions, a flux model was forced with and without SST--induced changes to the surface wind fields. The SST modification to the wind fields is based on a baroclinic argument as implemented by the University of Washington Planetary Boundary-Layer (UWPBL) model. Other input parameters include 2-m air temperature, 2-m dew point temperature, surface pressure (all from ERA--interim), and Reynolds Daily Optimum Interpolation Sea Surface Temperature (OISST). Flux model runs are performed every 6 hours starting in December 2002 and ending in November 2003. From these model outputs, seasonal, monthly, and daily means of the difference between DeltaSST and no DeltaSST effects on sensible heat flux (SHF), latent heat flux (LHF), and surface stress are calculated. Since the greatest impacts occur during the winter season, six additional December-January-February (DJF) seasons were analyzed for 1987--1990 and 1999--2002. The greatest differences in surface turbulent fluxes are concentrated near strong SST fronts associated with the Gulf Stream and Kuroshio Extension. On average, 2002---2003 DJF seasonal differences in SHF

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

Science.gov (United States)

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.

Compressor Calorimeter Test of R-410A Alternative: R-32/134a Mixture Using a Scroll Compressor

Energy Technology Data Exchange (ETDEWEB)

Shrestha, Som S [ORNL; Sharma, Vishaldeep [ORNL; Abdelaziz, Omar [ORNL

2014-02-01

As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares the performance of lower-GWP alternative refrigerant R-32 + R-134a mixture, to that of refrigerant R-410A (baseline) in a scroll compressor designed for air-conditioning and heat pump applications. These comparisons were carried out via compressor calorimeter tests performed on a compressor designed for refrigerant R-410A and having a nominal rated capacity of 21,300 Btu/hr. Tests were conducted over a suction dew point temperature range of 10 F to 55 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat, and 65 F suction temperature. A liquid subcooling level of 15 F was maintained for all the test conditions. The tests showed that the discharge temperature of the alternative refrigerant was higher than that of R-410A at all test conditions. Also, the energy efficiency ratio (EER) and cooling capacity of compressor using the alternative refrigerant were slightly lower in comparison to that of R-410A.

Energy Balance, Evapo-transpiration and Dew deposition in the Dead Sea Valley

Science.gov (United States)

Metzger, Jutta; Corsmeier, Ulrich

2016-04-01

The Dead Sea is a unique place on earth. It is a terminal hypersaline lake, located at the lowest point on earth with a lake level of currently -429 m above mean sea level (amsl). It is located in a transition zone of semiarid to arid climate conditions, which makes it highly sensible to climate change (Alpert1997, Smiatek2011). The Virtual Institute DEad SEa Research Venue (DESERVE) is an international project funded by the German Helmholtz Association and was established to study coupled atmospheric hydrological, and lithospheric processes in the changing environment of the Dead Sea. At the moment the most prominent environmental change is the lake level decline of approximately 1 m / year due to anthropogenic interferences (Gertman, 2002). This leads to noticeable changes in the fractions of the existing terrestrial surfaces - water, bare soil and vegetated areas - in the valley. Thus, the partitioning of the net radiation in the valley changes as well. To thoroughly study the atmospheric and hydrological processes in the Dead Sea valley, which are driven by the energy balance components, sound data of the energy fluxes of the different surfaces are necessary. Before DESERVE no long-term monitoring network simultaneously measuring the energy balance components of the different surfaces in the Dead Sea valley was available. Therefore, three energy balance stations were installed at three characteristic sites at the coast-line, over bare soil, and within vegetation, measuring all energy balance components by using the eddy covariance method. The results show, that the partitioning of the energy into sensible and latent heat flux on a diurnal scale is totally different at the three sites. This results in gradients between the sites, which are e.g. responsible for the typical diurnal wind systems at the Dead Sea. Furthermore, driving forces of evapo-transpiration at the sites were identified and a detailed analysis of the daily evaporation and dew deposition rates

Developmental responses of bread wheat to changes in ambient temperature following deletion of a locus that includes FLOWERING LOCUS T1.

Science.gov (United States)

Dixon, Laura E; Farré, Alba; Finnegan, E Jean; Orford, Simon; Griffiths, Simon; Boden, Scott A

2018-01-04

FLOWERING LOCUS T (FT) is a central integrator of environmental signals that regulates the timing of vegetative to reproductive transition in flowering plants. In model plants, these environmental signals have been shown to include photoperiod, vernalization, and ambient temperature pathways, and in crop species, the integration of the ambient temperature pathway remains less well understood. In hexaploid wheat, at least 5 FT-like genes have been identified, each with a copy on the A, B, and D genomes. Here, we report the characterization of FT-B1 through analysis of FT-B1 null and overexpression genotypes under different ambient temperature conditions. This analysis has identified that the FT-B1 alleles perform differently under diverse environmental conditions; most notably, the FT-B1 null produces an increase in spikelet and tiller number when grown at lower temperature conditions. Additionally, absence of FT-B1 facilitates more rapid germination under both light and dark conditions. These results provide an opportunity to understand the FT-dependent pathways that underpin key responses of wheat development to changes in ambient temperature. This is particularly important for wheat, for which development and grain productivity are sensitive to changes in temperature. © 2018 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Optimum design of vaporizer fin with liquefied natural gas by numerical analysis

International Nuclear Information System (INIS)

Jeong, Hyo Min; Chung, Han Shik; Lee, Sang Chul; Kong, Tae Woo; Yi, Chung Seub

2006-01-01

Generally, the temperature drop under 0 .deg. C on vaporizer surface creates frozen dews. This problem seems to increase as the time progress and humidity rises. In addition, the frozen dews create frost deposition. Consequently, heat transfer on vaporizer decreases because frost deposition causes adiabatic condition. Therefore, it is very important to solve this problem. This paper aims to study of the optimum design of used vaporizer at local LNG station. In this paper, experimental results were compared with numerical results. Geometries of numerical and experimental vaporizers were identical. Studied parameters of vaporizer are angle between two fins (Φ) and fin thickness (TH F ). Numerical analysis results were presented through the correlations between the ice layer thickness (TH ICE ) on the vaporizer surface to the temperature distribution of inside vaporizer (T IN ), fin thickness (TH F ), and angle between two fins (Φ). Numerical result shows good agreement with experimental outcome. Finally, the correlations for optimum design of vaporizer are proposed on this paper

Water harvesting for young trees using Peltier plates powered by photovoltaic solar energy

OpenAIRE

Muñoz-García, Miguel Angel; Moreda Cantero, Guillermo P.; Raga Arroyo, Manuela Pilar; Marín González, Omar

2012-01-01

Young trees transplanted from nursery into open field require a minimum amount of soil moisture to successfully root in their new location, especially in dry-climate areas. One possibility is to obtain the required water from air moisture. This can be achieved by reducing the temperature of a surface below the air dew point temperature, inducing water vapor condensation on the surface. The temperature of a surface can be reduced by applying the thermoelectric effect, with Peltier modules powe...

Full scale investigation on aerogel windows exposed to real climatic conditions

DEFF Research Database (Denmark)

Schultz, Jørgen Munthe; Nielsen, Lars Thomsen

-filling and hard low-emissivity coatings. The energy saving is reached without significant change in the indoor thermal comfort level.Highly insulating glazing types as aerogel glazings and triple-layered low-energy glazings lead to outside surface temperatures on the glazing that often are below the dew point...

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

Directory of Open Access Journals (Sweden)

F. Hurter

2013-11-01

Full Text Available 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

Modeling the condensation of sulfuric acid and water on the cylinder liner of a large two-stroke marine diesel engine

DEFF Research Database (Denmark)

Cordtz, Rasmus Faurskov; Mayer, Stefan; Eskildsen, Svend S.

2018-01-01

how fuel sulfur content, charge air humidity and liner temperature variations affects the deposition of water and sulfuric acid at low load operation. A phenomenological engine model is applied to simulate the formation of cylinder/bulk gas combustion products and dew points comply with H2O–H2SO4...

Modelling thermal stratification in the North Sea: Application of a 2-D potential energy model

DEFF Research Database (Denmark)

Nielsen, Morten Holtegaard; St. John, Michael

2001-01-01

is forced with wind, dew point temperature from Ekofisk oilfield in the central North Sea, and tidal current and atmospheric radiation. The model is used to simulate the seasonal cycle of stratification in the central North Sea in the years 1988, 1989 and 1990 and is compared to density profiles...

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

Science.gov (United States)

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 7: July

Science.gov (United States)

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 4: April

Science.gov (United States)

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.

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

Science.gov (United States)

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 10: October

Science.gov (United States)

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.

Meteorological measurements performed at the Saclay Centre of Nuclear Studies, and used equipment

International Nuclear Information System (INIS)

Levrard, A.

1960-01-01

This note first recalls the objective of meteorological measurements performed at the CENS station atmospheric radioactivity control station. It briefly recalls some definitions and notions in meteorology: atmosphere vertical structure, atmospheric humidity, atmospheric pressure, weather fronts and passage of disturbances, cloud systems. It indicates measurements performed on a daily basis (temperature in the shelter, minimum and maximum temperature, relative humidity, dew point temperature, atmospheric pressure, soil condition, present weather, visibility, past weather, cloudiness, precipitations, miscellaneous phenomena), recorded measurements (wind strength and direction, atmospheric pressure, relative humidity, temperature, pluviometry), while indicating and presenting corresponding measurement devices

Horns Rev 2 offshore wind farm photo case with wakes observed in 2016

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Nygaard, Nicolai Gayle; Volker, Patrick

results from atmospheric WRF meso-scale modelling, Park wake model and large eddy simulation wake model are prepared and analysed. At the time of the photos a humid and warm air mass was advected from the southwest over cold sea. The dew-point temperature was such that cold-water advection fog formed...

Compressor Calorimeter Test of R-404A Alternatives ARM-31a, D2Y-65, L-40, and R32 + R-134a Mixture using a Scroll Compressor

Energy Technology Data Exchange (ETDEWEB)

Shrestha, Som S [ORNL; Sharma, Vishaldeep [ORNL; Abdelaziz, Omar [ORNL

2013-08-01

As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares the performance of four lower-GWP alternative refrigerants, ARM-31a, D2Y-65, L-40, and R-32 + R-134a mixture, to that of refrigerant R-404A (baseline) in a scroll compressor designed for medium temperature refrigeration applications. These comparisons were carried out via compressor calorimeter tests performed on a compressor designed for refrigerant R-404A and having a nominal rated capacity of 23,500 Btu/hr. Tests were conducted over a suction dew point temperature range of -10 F to 35 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat, and 65 F suction temperature. A liquid subcooling level of 10 F to 15 F was maintained for all the test conditions. However, the cooling capacities reported in this study are normalized for 0 F subcooling. The tests showed that the compressor energy efficiency ratio (EER) and cooling capacity with all four alternative refrigerants tested are higher at higher saturation suction and saturation discharge temperature and lower at lower saturation suction and saturation discharge temperature, compared to that of R-404A. Discharge temperatures of all the alternative refrigerants were higher than that of R-404A at all test conditions.

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-05-06

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

KAUST Repository

Ma, Zhiwei

2013-01-01

The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

Measuring method for heat-shrinkage of fuel pellet

International Nuclear Information System (INIS)

Komono, Akira; Ishizaki, Jin; Inaki, Kiyohiro.

1997-01-01

The present invention concerns a method of determining an amount of heat-shrinkage of UR 2 pellets containing gadolinium oxide (Gd 2 O 2 ) based on the difference of the density thereof before and after heating. In a heat shrinkage test of UO 2 pellets containing from 1.0 to 15.0% by weight of gadolinium oxide, the amount of heat-shrinkage is measured under the condition of heat-retaining temperature: from 1700 to 1750degC, temperature elevation time and lowering time: from 90 to 120mins, heat-retaining time: 24hours, inert gas atmosphere, gas pressure: 0.35kg/cm 2 and gas dew point: from -55 to 40degC without changing O/M. This invention has a feature in the use of the inert gas and the elevation of the dew point of the gas. Then, oxygen dissociation phenomenon from crystal lattices of the fuel pellets is suppressed, and normal densification value is shown. Then, fuel pellets of good quality with less fluctuation of the heat-shrinkage can be obtained. (N.H.)

High-resolution grids of hourly meteorological variables for Germany

Science.gov (United States)

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.

Ecologic air-conditioning. A pilot plant for the geothermal and sorption supported air-conditioning in the HafenCity Hamburg; Oekologische Klimatisierung. Pilotanlage zur geothermisch- und sorptionsgestuetzten Klimatisierung in der HafenCity Hamburg

Energy Technology Data Exchange (ETDEWEB)

Ma, Xiaolong; Grabe, Juergen [Technische Univ. Hamburg-Harburg (Germany). Inst. fuer Geotechnik und Baubetrieb

2011-10-24

The relatively constant temperatures of the underground at a depth of 100 meters provide the opportunity to air-condition buildings with geothermal energy and economically. Currently, building air conditioning systems in Central Europe exhibit high growth rates. In summer, the task of an air conditioner is to cool and dehumidify air. Especially the dehumidification usually causes a high cooling demand, as the air is cooled below the dew point temperature of 12 C in order to condense out the water. The dew point is well below the demand for a comfortable room temperature of about 19 C. With this in mind, the authors of this contribution report on a principle of alternative dehumidification by means of a so-called sorption wheel. Sorption wheels use the hygroscopic properties of certain substances such as lithium chloride or silica gel in order to dehumidify the air. Thereby, the cooling demand significantly is reduced by the previous dehumidification. The regeneration of the sorption wheel requires heat. This heat can be provided by solar thermal plants and district heating. Since the air can no longer be dehumidified, rich supply temperatures between 16 and 19 C from. These temperatures can be achieved by means of near-surface temperature. Ground registers, geothermal energy probes or geothermal structures such as power poles are used as ground heat exchanger. The authors present the concept and the measurement results of the pilot plant in Hamburg's HafenCity.

Wind Farm Wake: The 2016 Horns Rev Photo Case

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Nygaard, Nicolai Gayle; Volker, Patrick

2017-01-01

are that a humid and warm air mass was advected from the southwest over cold sea and the dew-point temperature was such that cold-water advection fog formed in a shallow layer. The flow was stably stratified and the freestream wind speed was 13 m/s at hub height, which means that most turbines produced at or near...

Atmospheric precipitable water in Jos, Nigeria | Utah | Nigerian ...

African Journals Online (AJOL)

... the atmosphere of Jos in the month of August has a value of 4.44±0.47cm, while the minimum of 1.54±0.47cm was found in the month of February. The regression models have been presented and discussed. Keywords: Precipitable water vapour, dew-point temperature, relative humidity. Nigerian Journal of Physics Vol.

Influence of Adsorption and Capillary Pressure on Phase Equilibria Inside Shale Reservoirs

DEFF Research Database (Denmark)

Sandoval, Diego R.; Yan, Wei; Michelsen, Michael L.

2018-01-01

is moderate in comparison to the that at low pressure and high temperature. The adsorption effects are stronger for the gas bulk phase region, leading to bigger changes in the gas phase composition and the shift of the dew point curve. PVT simulations of two model reservoir fluid systems show significant...... envelope is different. In general, a much shrunk phase envelope with a shifted critical point is observed. The heavier components are preferentially adsorbed in the whole pressure and temperature range studied here. At high pressure and low temperature, the selectivity towards heavier components...

Evaluation of Dark Spots Formated on the High Temperature Metal Filter Elements

International Nuclear Information System (INIS)

Park, Seung Chul; Hwang, Tae Won; Moon, Chan Kook

2008-01-01

Metal filter elements were newly introduced to the high temperature filter (HTF) system in the low- and intermediate-level radioactive waste vitrification plant. In order to evaluate the performance of various metal materials as filter media, elements made of AISI 316L, AISI 904L, and Inconel 600 were included to the test set of filter elements. At the visual inspection to the elements performed after completion of each test, a few dark spots were observed on the surface of some elements. Especially they were found much more at the AISI 316L elements than others. To check the dark spots are the corrosion phenomena or not, two kinds of analyses were performed to the tested filter elements. Firstly, the surfaces or the cross sections of filter specimens cut out from both normal area and dark spot area of elements were analyzed by SEM/EDS. The results showed that the dark spots were not evidences of corrosion but the deposition of sodium, sulfur and silica compounds volatilized from waste or molten glass. Secondly, the ring tensile strength were analyzed for the ring-shape filter specimens cut out from each kind of element. The result obtained from the strength tested showed no evidence of corrosion as well. Conclusionally, depending on the two kinds of analysis, no evidences of corrosion were found at the tested metal filter elements. But the dark spots formed on the surface could reduce the effective filtering area and increase the overall pressure drop of HTF system. Thus, continuous heating inside filter housing up to dew point will be required normally. And a few long-period test should be followed for the exact evaluation of corrosion of the metal filter elements.

Validation for a new apparatus measuring water vapour enhancement factors up to 6 MPa

International Nuclear Information System (INIS)

Sairanen, H; Heinonen, M

2014-01-01

High accuracy dew-point measurements require a water vapour enhancement factor to correct the effects of pressure drop in a sampling line. The enhancement factor is also needed when a humidity quantity value is converted to another. In this paper a new apparatus for traceable measurements of the enhancement factor is presented along with the results of validation measurements with air and methane. The apparatus is designed for dew-point temperatures from −50 to +15 °C and the pressure range from atmospheric pressure up to 6 MPa. The performance of the apparatus was investigated by comparing measurement results to the literature data for air and the data calculated from published thermodynamic measurement results for methane. It is shown that the experimental results agree with the reference data within the estimated uncertainties. (paper)

Particle Swarm Optimization-based BP Neural Network for UHV DC Insulator Pollution Forecasting

Directory of Open Access Journals (Sweden)

Fangcheng Lü

2014-02-01

Full Text Available In order to realize the forecasting of the UHV DC insulator's pollution conditions, we introduced a PSOBP algorithm. A BP neural network (BPNN with leakage current, temperature, relative humidity and dew point as input neurons, and ESDD as output neuron was built to forecast the ESDD. The PSO was used to optimize the the BPNN, which had great improved the convergence rate of the BP neural network. The dew point as a brand new input unit has improved the iteration speed of the PSOBP algorithm in this study. It was the first time that the PSOBP algorithm was applied to the UHV DC insulator pollution forecasting. The experiment results showed that the method had great advantages in accuracy and speed of convergence. The research showed that this algorithm was suitable for the UHV DC insulator pollution forecasting.

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

Science.gov (United States)

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.

Measurement and calculation of gas compressibility factor for condensate gas and natural gas under pressure up to 116 MPa

International Nuclear Information System (INIS)

Yan, Ke-Le; Liu, Huang; Sun, Chang-Yu; Ma, Qing-Lan; Chen, Guang-Jin; Shen, De-Ji; Xiao, Xiang-Jiao; Wang, Hai-Ying

2013-01-01

Highlights: • Volumetric properties of two reservoir fluid samples were measured with pressure up to 116 MPa. • Dew point pressures at four temperatures for condensate gas sample are obtained. • Correlations and thermodynamic model for describing gas compressibility factor under high pressure were compared. • The thermodynamic model recommended is most suitable for fluids produced from reservoirs with a wide pressure range. -- Abstract: The volumetric properties of two reservoir fluid samples collected from one condensate gas well and one natural gas well were measured under four groups of temperatures, respectively, with pressure up to 116 MPa. For the two samples examined, the experimental results show that the gas compressibility factor increases with the increase of pressure. But the influence of the temperature is related to the range of the experimental pressure. It approximately decreases with the increase of temperature when the pressure is larger than (45 to 50) MPa, while there is the opposite trend when the pressure is lower than (45 to 50) MPa. The dew point pressure was also determined for the condensate gas sample, which decreases with the increase of temperature. The capabilities of four empirical correlations and a thermodynamic model based on equation of state for describing gas compressibility factor of reservoir fluids under high pressure were investigated. The comparison results show that the thermodynamic model recommended is the most suitable for fluids whatever produced from high-pressure reservoirs or conventional mild-pressure reservoirs

Composite material including nanocrystals and methods of making

Science.gov (United States)

Bawendi, Moungi G.; Sundar, Vikram C.

2010-04-06

Temperature-sensing compositions can include an inorganic material, such as a semiconductor nanocrystal. The nanocrystal can be a dependable and accurate indicator of temperature. The intensity of emission of the nanocrystal varies with temperature and can be highly sensitive to surface temperature. The nanocrystals can be processed with a binder to form a matrix, which can be varied by altering the chemical nature of the surface of the nanocrystal. A nanocrystal with a compatibilizing outer layer can be incorporated into a coating formulation and retain its temperature sensitive emissive properties.

Phase Envelope Calculations for Reservoir Fluids in the Presence of Capillary Pressure

DEFF Research Database (Denmark)

Lemus, Diego; Yan, Wei; Michelsen, Michael L.

2015-01-01

the bubble and dew point curves but also other quality lines with vapor fractions between 0 and 1. The algorithm has been used to calculate the phase envelopes of binary, multicomponent and reservoir fluid systems for pore radius from 10 to 50 nm. The presence of capillary pressure changes the saturation...... pressures in the whole phase envelope except at the critical point. The bubble point curve shows a negative change while the dew point curve shows positive and negative changes in the upper dew point branch and the lower dew point branch, respectively. In particular, the cricondentherm is also shifted...

Microclimatic conditions at the external surface of building envelopes

Energy Technology Data Exchange (ETDEWEB)

Kragh, M.K.

1998-12-31

The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat transfer from a double pane glazing is studied and measurement principles are discussed. Finally, a compilation of meteorological data for hygrothermal simulations, including estimation of driving rain, is described. System error estimation in relation to the window convection measurements, design notes on an apparatus for external convection measurement, formulae for conversion of relative humitity and dry-bulb temperature into dew point temperature. (EG) 66 refs.

Microclimatic conditions at the external surface of building envelopes

Energy Technology Data Exchange (ETDEWEB)

Kragh, M K

1999-12-31

The project is described, the motivation for the research and the microclimate is defined in relation to both building physics research and applications. Air temperatur, air humidity, solar radiation and air velocity are briefly considered, whilst driving rain and long-wave radiation are described in more detail. Convective heat transfer and surface coefficients are discussed, although they are not microclimatic factors, merely resulting from combinations of such factors. They are included as they are important in relation to transfer of heat and moisture at the surface of the building envelope. Driving rain measurement is the main area of interest, including development of measurement equipment. Long-wave irradiation is measured and compared with empirical formulae from the literature. Window convection heat transfer is another main area of interest. Nocturnal convective heat transfer from a double pane glazing is studied and measurement principles are discussed. Finally, a compilation of meteorological data for hygrothermal simulations, including estimation of driving rain, is described. System error estimation in relation to the window convection measurements, design notes on an apparatus for external convection measurement, formulae for conversion of relative humitity and dry-bulb temperature into dew point temperature. (EG) 66 refs.

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

Energy Technology Data Exchange (ETDEWEB)

Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Glissmeyer, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

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 dilution 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.

Investigation of selective oxidation in bake hardenable steel

International Nuclear Information System (INIS)

Madeira, Laureanny; Lins, Vanessa Cunha Freitas; Faria, Guilherme Augusto de; Guimaraes, Juliana Porto; Alvarenga, Evandro de Azevedo; Vilela, Jose Mario Carneiro

2010-01-01

The present work aims to characterize a steel bake hardenable (BH), annealed in three different dew points (-60°C, -30°C and 0°C), as the occurrence of selective oxidation, using the techniques of X-ray photo electronic spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES) and atomic force microscopy (AFM). The analysis by XPS showed that the alloying elements oxidized at different intensities for each dew point. Analysis by GDOES revealed that the surface and subsurface concentrations of these elements also varied with the dew point. The AFM images revealed that the size and shape of the oxides were different for each dew point. At the dew points of -30°C and -60°C the formation of oxides was local, while at 0°C the growth of oxides occurred uniform y on the surface of steels. (author)

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

Science.gov (United States)

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.

Importance of hydration in exoelectron emission from ceramic BeO

International Nuclear Information System (INIS)

Gammage, R.B.; Cheka, J.S.

1976-01-01

The influence of the state of hydration on the exoelectron emitting characteristics of BeO ceramic dosimeters for TSEE is very strong and very complex. For dosimetry the most unfavorable characteristics are a ruined TSEE peak shape and loss of intensity; this occurs if atmosphere moisture is allowed to condense onto, and evaporate from, the BeO surface. For unencapsulated dosimeters this occurs when the ambient temperature falls below the dew point. Immersion of irradiated detectors directly into liquid water for a few hours causes fading at a substantial rate, but surprisingly little change in the TSEE peak shape or intensity. The different behaviors with respect to immersion in liquid water and exposure to condensing atmospheric moisture present an enigma. Ceramic BeO TSEE dosimeters can only be used with confidence in atmospheres where below dew point conditions are avoidable, such as inside air conditioned buildings or encapsulated, dry air containers

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

Science.gov (United States)

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

Radiation forcing by the atmospheric aerosols in the nocturnal boundary layer

Science.gov (United States)

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.

EOS simulation and GRNN modeling of the constant volume depletion behavior of gas condensate reservoirs

Energy Technology Data Exchange (ETDEWEB)

Elsharkawy, A.M.; Foda, S.G. [Kuwait University, Safat (Kuwait). Petroleum Engineering Dept.

1998-03-01

Currently, two approaches are being used to predict the changes in retrograde gas condensate composition and estimate the pressure depletion behavior of gas condensate reservoirs. The first approach uses the equation of states whereas the second uses empirical correlations. Equations of states (EOS) are poor predictive tools for complex hydrocarbon systems. The EOS needs adjustment against phase behavior data of reservoir fluid of known composition. The empirical correlation does not involve numerous numerical computations but their accuracy is limited. This study presents two general regression neural network (GRNN) models. The first model, GRNNM1, is developed to predict dew point pressure and gas compressibility at dew point using initial composition of numerous samples while the second model, GRNNM2, is developed to predict the changes in well stream effluent composition at any stages of pressure depletion. GRNNM2 can also be used to determine the initial reservoir fluid composition using dew point pressure, gas compressibility at dew point, and reservoir temperature. These models are based on analysis of 142 sample of laboratory studies of constant volume depletion (CVD) for gas condensate systems forming a total of 1082 depletion stages. The database represents a wide range of gas condensate systems obtained worldwide. The performance of the GRNN models has been compared to simulation results of the equation of state. The study shows that the proposed general regression neural network models are accurate, valid, and reliable. These models can be used to forecast CVD data needed for many reservoir engineering calculations in case laboratory data is unavailable. The GRNN models save computer time involved in EOS calculations. The study also show that once these models are properly trained they can be used to cut expenses of frequent sampling and laborious experimental CVD tests required for gas condensate reservoirs. 55 refs., 13 figs., 6 tabs.

Counter flow cooling drier with integrated heat recovery

Science.gov (United States)

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.

DINEOF reconstruction of clouded images including error maps – application to the Sea-Surface Temperature around Corsican Island

Directory of Open Access Journals (Sweden)

J.-M. Beckers

2006-01-01

Full Text Available We present an extension to the Data INterpolating Empirical Orthogonal Functions (DINEOF technique which allows not only to fill in clouded images but also to provide an estimation of the error covariance of the reconstruction. This additional information is obtained by an analogy with optimal interpolation. It is shown that the error fields can be obtained with a clever rearrangement of calculations at a cost comparable to that of the interpolation itself. The method is presented on the reconstruction of sea-surface temperature in the Ligurian Sea and around the Corsican Island (Mediterranean Sea, including the calculation of inter-annual variability of average surface values and their expected errors. The application shows that the error fields are not only able to reflect the data-coverage structure but also the covariances of the physical fields.

ANTISEPTIC SPRAY BASED ON STABILIZED SILVER PARTICLES: AN ANALYSIS OF ANTISEPTIC PROPERTIES AND COMPREHENSIVE COMPARISON

Directory of Open Access Journals (Sweden)

Manuilov, A.M.

2018-04-01

Full Text Available Introduction. It's known that some antiseptic sprays based on alcohols can provoke the formation of multi-resistant strains of pathogenic microorganisms. In addition, alcoholic antiseptics has a number of restrictions to use, for example, they can't to be used in even the presence of micro-trauma on the skin, their ingression into the body and mucous membranes is unacceptable. Alternative can be natural antiseptics based on colloidal silver or silver nanoparticles, as well as silver in ionic form. However, such antiseptics has low efficacy against the most dangerous strains. Company Modern Biochem Technologies Ltd. announced the development of a portable device that generates a natural and safe antiseptic Dew, based on stabilized silver particles. Antiseptic Dew surpasses the vast majority of antiseptics based on silver, and is not inferior in effectiveness to antiseptics based on alcohols. This work is devoted to testing the declared characteristics of Dew and its comparison with antiseptics based on colloidal silver, silver nanoparticles and isopropyl alcohol. Materials and methods. To test the antiseptic effect of these agents, we used four test strains from the American Type Culture Collection: E. Coli ATCC 25922, Staphylococcus Aureus ATCC 25923, Candida Albicans ATCC 885-653 and Proteus Vulgaris ATCC 4636 with billion concentration of colony forming units in 1 ml (108 – 109 CFU/mL, ln CFU/mL = 19.57 ... 20.72. Sowing and screening of cultures were performed on sterile Petri dishes according to the standard procedure. Antiseptic Dew was prepared by prototype provided by Modern Biochem Technologies. The antiseptics of comparison were purchased in Kharkiv, Ukraine. The treatment of contaminated surfaces was performed using mechanical pump sprayers. In accordance with the internal protocol, 1 ml of antiseptic was sprayed from the distance of 10 cm onto the infected surface. To determine the silver content in the Dew, we were used atomic

The urban heat island dynamics during heat waves: a study of cities in the United States

Science.gov (United States)

Hu, Leiqiu

2016-04-01

The urban heat island (UHI) is a common phenomenon describing that metropolitan areas are usually warmer than their rural surroundings. This effect is compounded by extreme heat events, which are a leading cause of weather-related human mortality in many countries worldwide. However, the spatial and diurnal variability of temperature and humidity in urban and adjacent rural areas during extreme heat events is not well measured and therefore not well understood. The recently developed dataset of near-surface air and dew temperature from MODIS atmospheric profiles and the new method for the UHI quantification--urban heat island curve are used to quantify the urban climatic changes during heat waves in cities of the United States. The enhanced and weakened UHIs are observed in various cities. The causes of UHI changes during heat waves are discussed, including climate region, vegetation type and amount, city geolocation, etc.

Computer modeling of the sensitivity of a laser water vapor sensor to variations in temperature and air speed

Science.gov (United States)

Tucker, George F.

1994-01-01

Currently, there is disagreement among existing methods of determining atmospheric water vapor concentration at dew-points below -40 C. A major source of error is wall effects which result from the necessity of bringing samples into the instruments. All of these instruments also have response times on the order of seconds. NASA Langley is developing a water vapor sensor which utilizes the absorption of the infrared radiation produced by a diode laser to estimate water vapor concentration. The laser beam is directed through an aircraft window to a retroreflector located on an engine. The reflected beam is detected by an infrared detector located near the laser. To maximize signal to noise, derivative signals are analyzed. By measuring the 2f/DC signal and correcting for ambient temperature, atmospheric pressure and air speed (which results in a Doppler shifting of the laser beam), the water vapor concentration can be retrieved. Since this is an in situ measurement there are no wall effects and measurements can be made at a rate of more than 20 per second. This allows small spatial variations of water vapor to be studied. In order to study the sensitivity of the instrument to variations in temperature and air speed, a computer program which generated the 2f, 3f, 4f, DC and 2f/DC signals of the instrument as a function of temperature, pressure and air speed was written. This model was used to determine the effect of errors in measurement of the temperature and air speed on the measured water vapor concentration. Future studies will quantify the effect of pressure measurement errors, which are expected to be very small. As a result of these studied, a retrieval algorithm has been formulated, and will be applied to data taken during the PEM-West atmospheric science field mission. Spectroscopic studies of the water vapor line used by the instrument will be used to refine this algorithm. To prepare for these studies, several lasers have been studied to determine their

Properties of cast CF-8 stainless-steel weldments at cryogenic temperatures

International Nuclear Information System (INIS)

Chow, J.G.Y.; Klamut, C.J.

1981-01-01

ISABELLE is a 400 x 400 GeV proton-proton colliding beam accelerator now under construction at Brookhaven National Laboratory. The beams will be guided and focused by superconducting magnets. A total of 722 dipole beam bending magnets and 280 quadrupole beam focusing magnets are required. Centrifugally cast CF-8 stainless steel tubes were selected to provide a rigid support and to house the superconducting magnet assembly. The selection of this material for the support tubes is discussed by Dew-Hughes and Lee. Their study indicates that the presence of delta ferrite strengthens the material but causes a decrease in ductility if the ferrite content is greater than 10%. Brown and Tobler found that the fracture toughness is also decreased as the delta ferrite content is increased

A synthetic-dynamic method for water solubility measurements in high pressure CO_2 using ATR–FTIR spectroscopy

International Nuclear Information System (INIS)

Comak, Gurbuz; Foltran, Stéphanie; Ke, Jie; Pérez, Eduardo; Sánchez-Vicente, Yolanda; George, Michael W.; Poliakoff, Martyn

2016-01-01

Highlights: • A synthetic method using ATR–FTIR spectroscopy has been developed to measure the solubility of water in CO_2_. • New data have been obtained for the dew point of the water at 4.05 MPa, 5.05 MPa and 6.03 MPa. • These data fill a gap in the literature and could be of significance for CO_2 transport in pipelines for CCS technology. - Abstract: A new synthetic method for studying phase behaviour is described using Attenuated Total Reflection (ATR) spectroscopy. The method has been developed to provide relevant information on the solubility of water in CO_2. The dew point of water has been determined at three different pressures, viz. (4.05, 5.05 and 6.03) MPa with mole fractions of water between 0.01 and 0.04. The data obtained fill the gap in the literature in these regions of pressures and temperatures and could be of high importance in the context of Carbon Capture and Storage (CCS) technology. Indeed, the presence of water in the captured CO_2 could damage the pipeline used for CO_2 transport. Hence, it is very important to have a fully understanding of the behaviour of the (CO_2 + H_2O) mixtures in wide range of temperature relevant for CCS.

Determination of Critical Parameters of Carbon Dioxide+ Butyraldehyde System with Different Compositions

Institute of Scientific and Technical Information of China (English)

ZHANG Jing-chang; GAO Xi-xin; CAO Wei-liang

2005-01-01

Supercritical carbon dioxide( SC-CO2 ) is considered in green chemistry as a substitute for conventional solvents in chemical reactions due to its environmentally benign character. Recently we have reported the homogeneous hydroformylation of propylene in supercritical carbon dioxide( SC-CO2 ), which is an example of this kind of application of carbon dioxide. The determination for the critical parameters of carbon dioxide + butyraldehyde mixtures is necessary for this reaction design which is the focus of the present paper. The critical parameters of the binary systems were determined via the static visual method at a constant volume with the molar fraction of butyraldehyde ranging from 1.0%to 2. 2% and the pressure ranging from 5 to 10 MPa. The experimental results show that the critical pressure and temperature increased with increasing the molar fraction of butyraldehyde. The bubble(dew) temperatures and the bubble (dew) pressures for the binary systems were also determined experimentally. The p-T Figures at different compositions of the binary systems were described. In addition, the critical compressibility factors Zc of the binary systems at different concentrations of n-butyraldehyde were calculated. It was found that the critical compressibility factor values of the binary systems decreased with increasing the molar fraction of n-butyraldehyde in the experimental range.

Impact of pipes networks simplification on water hammer phenomenon

Indian Academy of Sciences (India)

problem; the finite difference method using water hammer and mass oscillation ... Mohamed (2003) introduced the effect of different parameters such as time of valve closure, ..... for computing the water age equivalent diameter, Dew. Dew = ⎡.

A short note on the inclusion of sultriness issues in perceived temperature in mild climates

Science.gov (United States)

Staiger, Henning; Laschewski, Gudrun; Matzarakis, Andreas

2018-01-01

Sultriness is a specific case in thermal perception under warm/humid environments and frequently applied in German operational weather forecast and is assumed if the dew-point temperature t d exceeds a threshold of 16.5 °C. In perceived temperature ( PT), which is based on the ASHRAE two-node-model, a Central European climatology was prepared of the classical predicted mean vote ( PMV), exclusively linked to thermal stress, and the so-called rational PMV* that additionally accounts for the humidity in the meteorological environment and is closely linked to thermal strain. The standard deviation of the difference Δ PMV = PMV* - PMV over PMV reveals a similarity to the appearance of sultriness that suggests as side effect of the PT parameterisation a thermophysiologically based definition of sultriness: "Under warm/humid conditions a subject adapted to mild climatologic conditions perceives sultriness if the actual value of Δ PMV exceeds the long-term mean by more than its single standard deviation". This definition accounts for all environmental and subject related variables influencing the thermal state of the body and is in accordance with all in the literature described properties in the perception of sultriness. The two definitions coincide more or less at daylight hours for t d values markedly beyond the threshold. However, in the t d threshold region, the PT-derived definition offers stronger differentiated patterns and is significantly less frequent at nighttime than the mono-causal definition. For given PT values, the sensible heat flux via the skin shows an increase under a sultry environment, whereas the latent is reduced; skin and core temperatures as well as the skin blood flow are also less. In any case, PT-derived sultriness is linked with an increased thermal strain on the body temperatures, which is a measure of discomfort caused by increased humidity and/or dissatisfaction with the thermal environment. This confirms the thermal uncomfortable

Battery system with temperature sensors

Science.gov (United States)

Wood, Steven J.; Trester, Dale B.

2012-11-13

A battery system to monitor temperature includes at least one cell with a temperature sensing device proximate the at least one cell. The battery system also includes a flexible member that holds the temperature sensor proximate to the at least one cell.

Inconing solar radiation estimates at terrestrial surface using meteorological satellite

International Nuclear Information System (INIS)

Arai, N.; Almeida, F.C. de.

1982-11-01

By using the digital images of the visible channel of the GOES-5 meteorological satellite, and a simple radiative transfer model of the earth's atmosphere, the incoming solar radiation reaching ground is estimated. A model incorporating the effects of Rayleigh scattering and water vapor absorption, the latter parameterized using the surface dew point temperature value, is used. Comparisons with pyranometer observations, and parameterization versus radiosonde water vapor absorption calculation are presented. (Author) [pt

Moving Advanced Desiccant Materials into Mainstream Non-CFC Cooling Products

Energy Technology Data Exchange (ETDEWEB)

Sand, J. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grossman, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fairchild, P. D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gross, I. L. [Engelhard/ICC, Hatboro, PA (United States). Fresh Air Solutions

2004-12-30

Desiccant dehumidification technology is emerging as a technically viable alternative for comfort conditioning in many commercial and institutional buildings. Attempts to improve the indoor air quality of buildings has resulted in increasingly stringent guidelines for occupant outdoor air ventilation rates. Additionally, revised building heating, ventilating, and air-conditioning (HVAC) design criteria based on regional peak dew point data highlight the important of the latent (moisture removal) building load relative to the sensible (temperature) building load.

Laser Control of Self-Organization Process in Microscopic Region and Fabrication of Fine Microporous Structure

OpenAIRE

Matsumura, Yukimasa; Inami, Wataru; Kawata, Yoshimasa

2012-01-01

We present a controlling technique of microporous structure by laser irradiation during self-organization process. Self-organization process is fabrication method of microstructure. Polymer solution was dropped on the substrate at high humid condition. Water in air appears dropping air temperature below the dew point. The honeycomb structure with regularly aligned pores on the film was fabricated by attaching water droplets onto the solution surface. We demonstrate that it was possible to pre...

Dew formation and activity of biological crusts

NARCIS (Netherlands)

Veste, M.; Heusinkveld, B.G.; Berkowicz, S.M.; Breckle, S.W.; Littmann, T.; Jacobs, A.F.G.

2008-01-01

Biological soil crusts are prominent in many drylands and can be found in diverse parts of the globe including the Atacama desert, Chile, the Namib desert, Namibia, the Succulent-Karoo desert, South Africa, and the Negev desert, Israel. Because precipitation can be negligible in deserts ¿ the

Condensation of water vapour on moss-dominated biological soil ...

Indian Academy of Sciences (India)

plant growth chamber using an electronic balance recording the weight of condensation. There was ..... Beysens (1995) studied the control of dew for- mation and ..... Subramanian A R and Kesava-Rao A V R 1983 Dew fall in sand dune areas ...

Comparative study of the performance of the M-cycle counter-flow and cross-flow heat exchangers for indirect evaporative cooling – Paving the path toward sustainable cooling of buildings

International Nuclear Information System (INIS)

Zhan, Changhong; Duan, Zhiyin; Zhao, Xudong; Smith, Stefan; Jin, Hong; Riffat, Saffa

2011-01-01

This paper provides a comparative study of the performance of cross-flow and counter-flow M-cycle heat exchangers for dew point cooling. It is recognised that evaporative cooling systems offer a low energy alternative to conventional air conditioning units. Recently emerged dew point cooling, as the renovated evaporative cooling configuration, is claimed to have much higher cooling output over the conventional evaporative modes owing to use of the M-cycle heat exchangers. Cross-flow and counter-flow heat exchangers, as the available structures for M-cycle dew point cooling processing, were theoretically and experimentally investigated to identify the difference in cooling effectiveness of both under the parallel structural/operational conditions, optimise the geometrical sizes of the exchangers and suggest their favourite operational conditions. Through development of a dedicated computer model and case-by-case experimental testing and validation, a parametric study of the cooling performance of the counter-flow and cross-flow heat exchangers was carried out. The results showed the counter-flow exchanger offered greater (around 20% higher) cooling capacity, as well as greater (15%–23% higher) dew-point and wet-bulb effectiveness when equal in physical size and under the same operating conditions. The cross-flow system, however, had a greater (10% higher) Energy Efficiency (COP). As the increased cooling effectiveness will lead to reduced air volume flow rate, smaller system size and lower cost, whilst the size and cost are the inherent barriers for use of dew point cooling as the alternation of the conventional cooling systems, the counter-flow system is considered to offer practical advantages over the cross-flow system that would aid the uptake of this low energy cooling alternative. In line with increased global demand for energy in cooling of building, largely by economic booming of emerging developing nations and recognised global warming, the research

Experimental investigation of a building integrated photovoltaic/thermal roof collector combined with a liquid desiccant enhanced indirect evaporative cooling system

International Nuclear Information System (INIS)

Buker, Mahmut Sami; Mempouo, Blaise; Riffat, Saffa B.

2015-01-01

Highlights: • Novel solar thermal collector for liquid desiccant air conditioning was introduced. • Low cost poly heat exchanger loop underneath the photovoltaic modules was proposed. • The ability of the combined system was experimentally investigated. • Water temperature in the loop could reach up to 35.5 °C during the tests. • This tri-gen system can supply 3 kW heating, 5.2 kW cooling and 10.3 MW h/year power. - Abstract: Large consumption of limited conventional fossil fuel resources, economic and environmental problems associated with the global warming and climate change have emphasized the immediate need to transition to renewable energy resources. Solar thermal applications along with renewable energy based cooling practices have attracted considerable interest towards sustainable solutions promising various technical, economic and environmental benefits. This study introduces a new concept on solar thermal energy driven liquid desiccant based dew point cooling system that integrates several green technologies; including photovoltaic modules, polyethylene heat exchanger loop and a combined liquid desiccant dehumidification-indirect evaporative air conditioning unit. A pilot scale experimental set-up was developed and tested to investigate the performance of the proposed system and influence of the various parameters such as weather condition, air flow and regeneration temperature. A cost effective, easy-to-make polyethylene heat exchanger loop was employed underneath PV panels for heat generation. In addition, a liquid desiccant enhanced dew point cooling unit was utilized to provide air conditioning through dehumidification of humid air and indirect evaporative cooling. The experimental results show that the proposed tri-generation system is capable of providing about 3 kW of heating, 5.2 kW of cooling power and 10.3 MW h/year power generation, respectively. The findings confirm the potential of the examined technology, and elucidate the

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

Science.gov (United States)

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

Observations of speciated atmospheric mercury at three sites in Nevada: Evidence for a free tropospheric source of reactive gaseous mercury

OpenAIRE

Weiss-Penzias, Peter; Gustin, Mae Sexauer; Lyman, Seth

2009-01-01

Air mercury (Hg) speciation was measured for 11 weeks (June–August 2007) at three sites simultaneously in Nevada, USA. Mean reactive gaseous Hg (RGM) concentrations were elevated at all sites relative to those reported for locations not directly influenced by known point sources. RGM concentrations at all sites displayed a regular diel pattern and were positively correlated with ozone (O3) and negatively correlated with elemental Hg (Hg0) and dew point temperature (Tdp). Superimposed on the d...

IR-spectroscopy of environmental relevant ice-aerosols: Analysis of phase transitions; IR-Spektrometrie umweltrelevanter Eisaerosole: Untersuchung von Phasenuebergaengen

Energy Technology Data Exchange (ETDEWEB)

Kessler, T. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Kuestenforschung

2002-07-01

Fourier transform infrared spectroscopy was used to investigate the transition area of water from the monomer to nanoparticles. To achieve the ambient temperature range from 130 K to 300 K in a collisional cooling cell a cooled gas plant was established. With the given parameters a transition temperature of 167 K was found. This temperature appeared to be a bifurcation point: small fluctuations of the temperature - due to the fuzzy control of the cell heating - caused distinct changes of the spectra. Slight increments of the temperature extend the transition period monomer/nanoparticle and let significant deviations to the typical particle spectrum occur (appearance and width of the band, respectively). The H{sub 2}O (D{sub 2}O)/He sample gas mixtures were generated by a reliable dew-point technique and were injected into the collisional cooling cell at the corresponding temperature. (orig.)

Outdoor fate and environmental impact of polymer solar cells through leaching and emission to rainwater and soil

DEFF Research Database (Denmark)

Espinosa Martinez, Nieves; Zimmermann, Yannick-Serge; Benatto, Gisele Alves dos Reis

2016-01-01

The emission of silver and zinc to the aqueous environment (rain, fog, dew) from polymer solar cells installed outdoors is presented. Studies included pristine solar cells and solar cells subjected to mechanical damage under natural weather conditions in Denmark. We find the emission of silver...

The Effect of Increasing Surface Albedo on Urban Climate and Air Quality: A Detailed Study for Sacramento, Houston, and Chicago

Directory of Open Access Journals (Sweden)

Zahra Jandaghian

2018-03-01

Full Text Available Increasing surface reflectivity in urban areas can decrease ambient temperature, resulting in reducing photochemical reaction rates, reducing cooling energy demands and thus improving air quality and human health. The weather research and forecasting model with chemistry (WRF-Chem is coupled with the multi-layer of the urban canopy model (ML-UCM to investigate the effects of surface modification on urban climate in a two-way nested approach over North America focusing on Sacramento, Houston, and Chicago during the 2011 heat wave period. This approach decreases the uncertainties associated with scale separation and grid resolution and equip us with an integrated simulation setup to capture the full impacts of meteorological and photochemical reactions. WRF-ChemV3.6.1 simulated the diurnal variation of air temperature reasonably well, overpredicted wind speed and dew point temperature, underpredicted relative humidity, overpredicted ozone and nitrogen dioxide concentrations, and underpredicted fine particular matters (PM2.5. The performance of PM2.5 is a combination of overprediction of particulate sulfate and underprediction of particulate nitrate and organic carbon. Increasing the surface albedo of roofs, walls, and pavements from 0.2 to 0.65, 0.60, and 0.45, respectively, resulted in a decrease in air temperature by 2.3 °C in urban areas and 0.7 °C in suburban areas; a slight increase in wind speed; an increase in relative humidity (3% and dew point temperature (0.3 °C; a decrease of PM2.5 and O3 concentrations by 2.7 µg/m3 and 6.3 ppb in urban areas and 1.4 µg/m3 and 2.5 ppb in suburban areas, respectively; minimal changes in PM2.5 subspecies; and a decrease of nitrogen dioxide (1 ppb in urban areas.

Interpretace měření hmotnosti usazených srážek pomocí automatického rosoměru

Czech Academy of Sciences Publication Activity Database

Fišák, Jaroslav; Chum, Jaroslav; Vojta, Jaroslav

2014-01-01

Roč. 67, č. 5 (2014), s. 129-134 ISSN 0026-1173 R&D Projects: GA ČR GA205/09/1918 Institutional support: RVO:68378289 Keywords : dew * dew gauge * deposited precipitation * precipitation amount Subject RIV: DI - Air Pollution ; Quality http://casmz.chmi.cz/2014_5.pdf

Internal state variable plasticity-damage modeling of AISI 4140 steel including microstructure-property relations: temperature and strain rate effects

Science.gov (United States)

Nacif el Alaoui, Reda

Mechanical structure-property relations have been quantified for AISI 4140 steel. under different strain rates and temperatures. The structure-property relations were used. to calibrate a microstructure-based internal state variable plasticity-damage model for. monotonic tension, compression and torsion plasticity, as well as damage evolution. Strong stress state and temperature dependences were observed for the AISI 4140 steel. Tension tests on three different notched Bridgman specimens were undertaken to study. the damage-triaxiality dependence for model validation purposes. Fracture surface. analysis was performed using Scanning Electron Microscopy (SEM) to quantify the void. nucleation and void sizes in the different specimens. The stress-strain behavior exhibited. a fairly large applied stress state (tension, compression dependence, and torsion), a. moderate temperature dependence, and a relatively small strain rate dependence.

Characterization of total ecosystem scale biogenic VOC exchange at a Mediterranean oak-hornbeam forest

Science.gov (United States)

Schallhart, S.; Rantala, P.; Nemitz, E.; Mogensen, D.; Tillmann, R.; Mentel, T. F.; Rinne, J.; Ruuskanen, T. M.

2015-10-01

Recently, the number and amount of biogenically emitted volatile organic compounds (VOCs) has been discussed vigorously. Depending on the ecosystem the published number varies between a dozen and several hundred compounds. We present ecosystem exchange fluxes from a mixed oak-hornbeam forest in the Po Valley, Italy. The fluxes were measured by a proton transfer reaction-time-of-flight (PTR-ToF) mass spectrometer and calculated by the eddy covariance (EC) method. Detectable fluxes were observed for twelve compounds, dominated by isoprene, which comprised over 65 % of the total flux emission. The daily average of the total VOC emission was 9.5 nmol m-2 s-1. Methanol had the highest concentration and accounted for the largest deposition. Methanol seemed to be deposited to dew, as the deposition happened in the early morning, right after the calculated surface temperature came closest to the calculated dew point temperature. We estimated that up to 27 % of the upward flux of methyl vinyl ketone (MVK) and methacrolein (MACR) originated from atmospheric oxidation of isoprene. A comparison between two flux detection methods (classical/visual and automated) was made. Their respective advantages and disadvantages were discussed and the differences in their results shown. Both provide comparable results; however we recommend the automated method with a compound filter, which combines the fast analysis and better flux detection, without the overestimation due to double counting.

Characterization of total ecosystem-scale biogenic VOC exchange at a Mediterranean oak–hornbeam forest

Directory of Open Access Journals (Sweden)

S. Schallhart

2016-06-01

Full Text Available Recently, the number and amount of biogenically emitted volatile organic compounds (VOCs has been discussed in great detail. Depending on the ecosystem, the published number varies between a dozen and several hundred compounds. We present ecosystem exchange fluxes from a mixed oak–hornbeam forest in the Po Valley, Italy. The fluxes were measured by a proton transfer reaction-time-of-flight (PTR-ToF mass spectrometer and calculated using the eddy covariance (EC method. Detectable fluxes were observed for up to 29 compounds, dominated by isoprene, which comprised over 60 % of the total upward flux (on a molar basis. The daily average of the total VOC upward flux was 10.4 nmol m−2 s−1. Methanol had the highest concentration and accounted for the largest downward flux. Methanol seemed to be deposited to dew, as the downward flux happened in the early morning, right after the calculated surface temperature came closest to the calculated dew point temperature.We estimated that up to 30 % of the upward flux of methyl vinyl ketone (MVK and methacrolein (MACR originated from atmospheric oxidation of isoprene. A comparison between two methods for the flux detection (manual and automated was made. Their respective advantages and disadvantages were discussed and the differences in their results shown. Both provide comparable results.

Developing HYDMN code to include the transient of MNSR

International Nuclear Information System (INIS)

Al-Barhoum, M.

2000-11-01

A description of the programs added to HYDMN code (a code for thermal-hydraulic steady state of MNSR) to include the transient of the same MNSR is presented. The code asks the initial conditions for the power (in k W) and the cold initial core inlet temperature (in degrees centigrade). A time-dependent study of the coolant inlet and outlet temperature, its speed, pool and tank temperatures is done for MNSR in general and for the Syrian MNSR in particular. The study solves the differential equations taken from reference (1) by using some numerical methods found in reference (3). The code becomes this way independent of any external information source. (Author)

Outdoor fate and environmental impact of polymer solar cells through leaching and emission to rainwater and soil

NARCIS (Netherlands)

Espinosa, Nieves; Zimmermann, Yannick-Serge; Reis Benatto, Dos Gisele A.; Lenz, Markus; Krebs, Frederik C.

2016-01-01

The emission of silver and zinc to the aqueous environment (rain, fog, dew) from polymer solar cells installed outdoors is presented. Studies included pristine solar cells and solar cells subjected to mechanical damage under natural weather conditions in Denmark. We find the emission of silver and

Compressor Calorimeter Test of R-410A Alternatives R-32, DR-5, and L-41a

Energy Technology Data Exchange (ETDEWEB)

Shrestha, Som S [ORNL; Mahderekal, Isaac [ORNL; Sharma, Vishaldeep [ORNL; Abdelaziz, Omar [ORNL

2013-02-01

As a contribution to the AHRI Low-GWP Alternative Refrigerants Evaluation Program (AREP), this study compares performance of alternative refrigerants R32, DR-5, and L-41A to that of refrigerant R-410A (baseline) in a scroll compressor designed for air-conditioning and heat pump applications. Compressor calorimeter tests were performed to evaluate the performance of the lower-GWP alternative refrigerants in place of the common refrigerant R-410A in a 36,000 Btu/hr compressor calorimeter using a compressor having a nominal rated capacity of 21,300 Btu/hr. Tests were conducted over a suction dew point temperature range of 10 F to 55 F in 5 F increments and a discharge dew point temperature range of 70 F to 140 F in 10 F increments. All the tests were performed with 20 F superheat, 40 F superheat and 65 F suction temperature. A liquid subcooling level of 15 F was maintained for all the test conditions. The tests showed that performance of these three lower-GWP alternative refrigerants is comparable to that of R-410A. For the 20 F superheat and 15 F subcooling test conditions, EERs of R32, DR-5, and L-41A were 90% to 99%, 96% to 99%, and 94% to 101%, respectively, compared to that of R-410A. Similarly, cooling capacities of R32, DR-5, and L-41A were 98% to 103%, 92% to 96%, and 84% to 92%, respectively, compared to that of R-410A.

Generation of a typical meteorological year for Hong Kong

International Nuclear Information System (INIS)

Chan, Apple L.S.; Chow, T.T.; Fong, Square K.F.; Lin, John Z.

2006-01-01

Weather data can vary significantly from year to year. There is a need to derive typical meteorological year (TMY) data to represent the long-term typical weather condition over a year, which is one of the crucial factors for successful building energy simulation. In this paper, various types of typical weather data sets including the TMY, TMY2, WYEC, WYEC2, WYEC2W, WYEC2T and IWEC were reviewed. The Finkelstein-Schafer statistical method was applied to analyze the hourly measured weather data of a 25-year period (1979-2003) in Hong Kong and select representative typical meteorological months (TMMs). The cumulative distribution function (CDF) for each year was compared with the CDF for the long-term composite of all the years in the period for four major weather indices including dry bulb temperature, dew point temperature, wind speed and solar radiation. Typical months for each of the 12 calendar months from the period of years were selected by choosing the one with the smallest deviation from the long-term CDF. The 12 TMMs selected from the different years were used for formulation of a TMY for Hong Kong

Unsteady-state analysis of a counter-flow dew point evaporative cooling system

KAUST Repository

Lin, J.; Thu, K.; Bui, T.D.; Wang, R.Z.; Ng, Kim Choon; Kumja, M.; Chua, K.J.

2016-01-01

temperature, humidity and velocity; (2) the settling time of the transient response ranges from 50 s to 300 s when the system operates under different inlet conditions; and (3) the average transient wet bulb effectiveness (1.00–1.06) of the system is observed

Flue gas moisture capacity calculation at the outlet of the condensation heat recovery unit

Directory of Open Access Journals (Sweden)

Galashov Nikolay

2017-01-01

Full Text Available As a result, study equation has been obtained which determine the flue gas moisture capacity at the outlet of the condensation heat recovery unit with an error of less than 1%. It possible to at the temperature of the flue gas below the dew point and the known air-fuel ratio efficient. The equation can be used to calculate plants operating on products of gas combustion without Use of tables and programs for calculating the water-vapor saturation pressure.

Effluents of toxic and corrosion-active components at coke-oven gas combustion

International Nuclear Information System (INIS)

Mikhajlov, G.S.; Afanas'ev, Yu.O.; Plotnikov, V.A.; Iskhakov, Kh.A.; Tikhov, S.D.; Gaus, A.I.; Nagibin, P.D.

1996-01-01

Various modes of coke-coal gas combustion are studied and dependence of concentration of nitrogen sulfur oxides and carbon monoxides originating in smoke gases on the air excess delivered to the combustion chamber is determined. The lowest summary releases of hazardous substances are achieved by the excess air coefficients α > 1.2 relative to modes of coke-coal gas combustion with smoke gases recirculation. The quantity of sulfur does not depend on the mode of fuel combustion and is determined by the total sulfur content in the fuel. To prevent the corrosion of low-temperature heat exchange surfaces it is necessary to heat up the feed-water up to the temperature exceeding the temperature of the coal gases dew point by 10-15 deg C. 10 refs

Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

Science.gov (United States)

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.

Characteristics of Sulfuric Acid Condensation on Cylinder Liners of Large Two-Stroke Marine Engines

DEFF Research Database (Denmark)

Cordtz, Rasmus Lage; Mayer, Stefan; Schramm, Jesper

. Formation of corrosive sulfuric acid in the cylinder gas is modeled with a cali-brated engine model that incorporates a detailed sulfur reaction mechanism. Condensation of sulfuric acid follows the analogy between heat and mass transfer. Average bulk gas acid dew points are calculated by applying two......-phase thermochemistry of the binary H2O-H2SO4 system. Max dew points of typically more than 200 °C are modeled close to max pressure and variations in terms of operating conditions are not large. However small increments of the dew point provided by e.g. the residual gas fraction, operating pressure, sulfur content...

Localisation inhabituelle du sarcome d'Ewing des parties molles ...

African Journals Online (AJOL)

Ewing's sarcoma of soft parts is a rare mesenchymal tumor of poor prognosis. Receiving an early diagnosis increases the chance of survival. In the absence of clinical and radiological features, it seems necessary to include it in the differential diagnosis which includes all the primitive tumour of soft parts and to hypothesize ...

Assessment of leak detection capability of Candu 6 annulus gas system using moisture injection tests

International Nuclear Information System (INIS)

Nho, Ki Man; Kim, Wang Bae

1998-01-01

The Candu 6 reactor assembly consists of an array of 380 pressure tubes, which are installed horizontally in a large cylindrical vessel, the Calandria, containing the low pressure heavy water moderator. The pressure tube is located inside calandria tube and the annulus between these tubes, which forms a closed loop with CO 2 gas recirculating, is called the Annulus Gas System (AGS). It is designed to give an alarm to the operator even for a small pressure tube leak by a very sensitive dew point meter so that he can take a preventive action for the pressure tbe rupture incident. To judge whether the operator action time is enough or not in the design of Wolsung 2, 3, and 4, the Leak Before Break (LBB) assessment is required for the analysis of the pressure tube failure accident. In order to provide the required data for the LBB assessment of Wolsung Units 2, 3, 4, a series of leak detection capability tests was performed by injecting controlled rates of heavy water vapour. The data of increased dew point and rates of rise were measured to determine the alarm set point for dew point rate of rise of Wolsung Unit 2. It was found that the response of the dew point depends on the moisture injection rate, CO 2 gas flow rate and the leak location. The test showed that Candu 6 AGS can detect the very small leaks less than few g/hr and dew point rate of rise alarm can be the most reliable alarm signal to warn the operator. Considering the present results, the first response time of dew point to the AGS CO 2 flow rate is approximated. (author)

High-Temperature Piezoelectric Sensing

Directory of Open Access Journals (Sweden)

Xiaoning Jiang

2013-12-01

Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

Summary of Data and Steps for Processing the 1997-2001 SRS Meteorological Database

International Nuclear Information System (INIS)

Weber, A.H.

2003-01-01

Every five years since the mid-1970s DOE has requested an update on the meteorological conditions at SRS in order to provide dose calculations for accident or routine release scenarios for onsite and offsite populations. The meteorological database includes wind speed, wind direction, temperature, dew point, and horizontal and vertical turbulence intensities. The two most recent databases prior to the current one were completed in 1998 for the time period 1992-96 (Weber, 1998) and one for 1987-91 (Parker, et. al., 1992). The current database covers the period 1997-2001. The advantage of updating the database every five years is that meteorological observations are steadily growing more complete and less subject to errors with the implementation of better electronic data archiving software and hardware, and improved data quality assurance procedures. Also, changes in the region's climate may be manifest

Liquid oil production from shale gas condensate reservoirs

Science.gov (United States)

Sheng, James J.

2018-04-03

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.

Urticaceae pollen concentration in the atmosphere of North Western Spain.

Science.gov (United States)

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.

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

Science.gov (United States)

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

Optimizing the energy efficiency of conventional multi-cylinder dryers in the paper industry

International Nuclear Information System (INIS)

Laurijssen, Jobien; De Gram, Frans J.; Worrell, Ernst; Faaij, Andre

2010-01-01

The paper industry is, with about 6% of the total worldwide industrial energy use, an energy-intensive industry. The drying section is with approximately 50% the largest energy consumer in a paper mill, energy use in this section is mainly heat use. Several options to decrease heat use in conventional multi-cylinder drying sections are investigated, calculating the effect on energy use. Optimization measures include a) decreasing the amount of water evaporation by applying additives in higher consistencies and by lowering the water viscosity, b) decreasing the heat use of water evaporation by increasing the dew point temperature of the dryer and c) increasing the amount of heat recovery by using exhaust air to not only pre-heat the incoming air but also to increase process water temperatures. These could all be achieved by retrofitting and/or choosing different processing conditions in existing factories. The combined thermal heat saving potential due to the optimization actions is 1.3 GJ h /t paper (or 32% of the drying section's heat use) as compared to the reference situation.

Site Study Plan for meteorology/air quality, Deaf Smith County site, Texas: Environmental Field Program: Preliminary draft

International Nuclear Information System (INIS)

1987-06-01

The Meteorological/Air Quality Site Study Plan describes a field program consisting of continuous measurements of surface (10-meter) wind speed and direction, temperature, humidity, dew point, pressure, and sensible heat flux (vertical). Air quality measurements will be limited to suspended particulate matter. After the first year of measurements, a 60-meter tower will be added to incorporate measurements needed for later modeling and dose calculations; these will include upper level winds, vertical temperature structure, and vertical wind speed. All of these measurements will be made at a site located within the 9-mi 2 site area but remote from the ESF. A second site, located near and downwind from the ESF, will monitor only particulate matter. The SSP describes the need for each study; its design and design rationale; analysis, management, and use of data, schedule of field activities, organization of field personnel and sample management, and quality assurance requirements. These studies will provide data needed to satisfy requirements contained in, or derived from the Salt Repository Project Requirements Document. 38 refs., 8 figs., 3 tabs

Temperatures and locations used by hibernating bats, including Myotis sodalis (Indiana bat), in a limestone mine: implications for conservation and management.

Science.gov (United States)

Brack, Virgil

2007-11-01

Understanding temperatures used by hibernating bats will aid conservation and management efforts for many species. A limestone mine with 71 km of passages, used as a hibernaculum by approximately 30,000 bats, was visited four times during a 6-year period. The mine had been surveyed and mapped; therefore, bats could be precisely located and temperatures (T (s)) of the entire hibernaculum ceiling accurately mapped. It was predicted that bats should hibernate between 5 and 10 degrees C to (1) use temperatures that allow a near minimal metabolic rate, (2) maximize the duration of hibernation bouts, (3) avoid more frequent and prolonged arousal at higher temperatures, (4) avoid cold and freezing temperatures that require an increase in metabolism and a decrease in duration of hibernation bouts or that could cause death, and (5) balance benefits of a reduced metabolic rate and costs of metabolic depression. The distribution of each species was not random for location (P block walls and sheltered alcoves, which perhaps dampened air movement and temperature fluctuations. Myotis lucifugus (little brown myotis) hibernated in colder, more variable areas (X = 7.2 +/- 2.6 degrees C). Myotis septentrionalis (northern myotis), Pipistrellus subflavus (eastern pipistrelle), and Eptesicus fuscus (big brown bat) typically hibernated in warm, thermally stable areas (X = 9.1 +/- 0.2 degrees C, X = 9.6 +/- 1.9 degrees C, and X = 9.5 +/- 1.5 degrees C, respectively). These data do not indicate that hibernacula for M. sodalis, an endangered species, should be manipulated to cool below 5 degrees C.

Deep Trek High Temperature Electronics Project

Energy Technology Data Exchange (ETDEWEB)

Bruce Ohme

2007-07-31

This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

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

Science.gov (United States)

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

2018-02-01

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

Test and evaluation of a method of utilizing flue gas below the dew point

Energy Technology Data Exchange (ETDEWEB)

Wilsdorf, J.; Mueller, R.

1983-09-01

Technological possibilities of using power plant waste heat for low temperature heating of buildings or for industrial heat supply are discussed. Waste heat is recovered with a water circulating heat exchanger to a degree of 15%. Diagrams are presented for a hot water supply system at conventional power generators of 600 to 2,500 kW. Heat balances for a small steam generator of 800 kg/h steam capacity are calculated, comparing the energy efficiency with and without low temperature heat recovery systems. Economic benefits, which can be realized with waste heat recovery systems are calculated. 8 references.

Tear osmolarity measurements in dry eye related to primary Sjögren's syndrome.

Science.gov (United States)

Utine, Canan Asli; Bıçakçıgil, Müge; Yavuz, Sule; Çiftçi, Ferda

2011-08-01

To evaluate the tear osmolarity in patients with dry eye syndrome related to primary Sjögren's Syndrome (SS). Twenty eyes of 10 patients with dry eye and primary SS (Group 1) and 20 eyes of 20 subjects who do not have dry eye syndrome (Group 2) were included in this cross-sectional study. In all eyes, ophthalmic examination was performed in the same order: International Ocular Surface Disease Index survey, visual acuity assessment, conjunctival hyperemia scoring, tear osmolarity measurement with TearLab(™) Osmolarity System, tear film break-up time assessment, corneal fluorescein staining scoring, ocular surface Lissamine Green staining scoring, anesthetized Schirmer test. Dry eye severity was graded according to Dry Eye Workshop (DEWS) classification system. Four eyes with grade 1, four eyes with grade 2, seven eyes with grade 3, and five eyes with grade 4 dryness, according to DEWS system, were included. The mean tear osmolarity value was 301.9 ± 11.40 mOsm/L (range: 290-328) in Group 1, and 294.85 ± 8.33 mOsm/L (range: 283-311) in Group 2 (p = 0.03). In Group 1, tear osmolarity values were positively correlated with OSDI scores (r(18) = 0.55, r(2) = 0.31, p = 0.01), DEWS classification grades (r(18) = 0.73, r(2) = 0.54, p dry eye syndrome related to primary SS compared to control subjects, and positively correlated with the severity of dry eye.

Calibration of moisture monitors

International Nuclear Information System (INIS)

Gutierrez, R.L.

1979-02-01

A method for calibrating an aluminum oxide hygrometer against an optical chilled mirror dew-point hygrometer has been established. A theoretical cross-point line of dew points from both hygrometers and a maximum moisture content of 10 ppM/sub v/ are used to define an area for calibrating the sensor probes of the aluminum oxide hygrometer

Images Borne on Dewy Lightning

DEFF Research Database (Denmark)

Isar, Nicoletta

2017-01-01

The Silent Book (Mutus Liber) printed in 1677 opens with an unusual picture for a 21st century viewer showing a male figure and a female alchemist wringing out the dew they have collected in sheets exposed to the air. One wonders why on earth one may try to squeeze and then store dew, and how it ...

Of Needles and Haystacks: Building an Accurate Statewide Dropout Early Warning System in Wisconsin

Science.gov (United States)

Knowles, Jared E.

2015-01-01

The state of Wisconsin has one of the highest four year graduation rates in the nation, but deep disparities among student subgroups remain. To address this the state has created the Wisconsin Dropout Early Warning System (DEWS), a predictive model of student dropout risk for students in grades six through nine. The Wisconsin DEWS is in use…

Climate related natural hazards management in the vulnerable regions of Uzbekistan - experiences in the frame of projects Climate Risk Management in Uzbekistan (CRM-Uz) and Water in Central Asia (CAWa)

Science.gov (United States)

Merkushkin, Alexander; Gafurov, Abror; Agaltseva, Natalya; Pak, Alexander; Mannig, Birgit; Paeth, Heiko; Vorogushyn, Sergiy; Unger-Shayesteh, Katy

2014-05-01

Increased frequency of natural hazards under conditions of observed climate change in Uzbekistan has become challenging concern and shows the need to develop more effective climate risk mechanisms towards improving the security of society and sustainable development. In the framework of presented study, the importance of drought monitoring and methodologies for early warning for such purposes in Uzbekistan are demonstrated. For the conditions of Uzbekistan, droughts are most dangerous climate related natural phenomenon. Therefore, the CRM-Uz Project on Climate Risk Management was established with focus on reducing climate risks, strengthening adaptive capacity for stimulating the development of early warning mechanisms, as well as to build up the basis for long-term investments. This serves to increase resilience to climate impacts in the country. In the frame of the CRM-Uz Project, Drought Early Warning System (DEWS), has been developed and implemented in one of the southern provinces of Uzbekistan (Kashkadarya). The main task of DEWS is to provide population with information on the possibility of upcoming drought season in advance. DEWS is used for the assessment, monitoring, prevention, early warning and decision making in this region. Such early warning system provides the required information to undertake appropriate measures against drought and to mitigate its adverse effects to society. It is clear that during years with expected drought the hydrological forecasts become much more important. Complex mathematical model which simulates of run-off formation as a basis of DEWS provides the seasonal hydrological forecasts that are used to inform all concerned sectors, especially the agricultural sector on water availability during the vegetation period. In the frame of cooperation with German Research Centre for Geosciences (GFZ) within the CAWa Project, the DEWS was extended through implementation of MODSNOW - the operational tool for snow cover monitoring at

Improving the strength of amalgams by including steel fibers

Energy Technology Data Exchange (ETDEWEB)

Cochran, Calvin T. [Hendrix College, Conway, AR 72032 (United States); Van Hoose, James R. [Siemens, Orlando, FL 32826 (United States); McGill, Preston B. [Marshall Space Flight Center, EM20, Huntsville, AL 35812 (United States); Grugel, Richard N., E-mail: richard.n.grugel@nasa.gov [Marshall Space Flight Center, EM30, Huntsville, AL 35812 (United States)

2012-05-30

Highlights: Black-Right-Pointing-Pointer A room temperature liquid Ga-In alloy was successfully substituted for mercury. Black-Right-Pointing-Pointer Physically sound amalgams with included steel fibers can be made. Black-Right-Pointing-Pointer A small volume fraction inclusion of fibers increased strength by {approx}20%. - Abstract: Mercury amalgams, due to their material properties, are widely and successfully used in dental practice. They are, however, also well recognized as having poor tensile strength. With the possibility of expanding amalgam applications it is demonstrated that tensile strength can be increased some 20% by including a small amount of steel fibers. Furthermore, it is shown that mercury can be replaced with a room temperature liquid gallium-indium alloy. Processing, microstructures, and mechanical test results of these novel amalgams are presented and discussed in view of means to further improve their properties.

From Space to the Rocky Intertidal: Using NASA MODIS Sea Surface Temperature and NOAA Water Temperature to Predict Intertidal Logger Temperature

Directory of Open Access Journals (Sweden)

Jessica R. P. Sutton

2017-02-01

Full Text Available The development of satellite-derived datasets has greatly facilitated large-scale ecological studies, as in situ observations are spatially sparse and expensive undertakings. We tested the efficacy of using satellite sea surface temperature (SST collected by NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS and local water temperature collected from NOAA buoys and onshore stations to estimate submerged intertidal mussel logger temperatures. Daily SST and local water temperatures were compared to mussel logger temperatures at five study sites located along the Oregon coastline. We found that satellite-derived SSTs and local water temperatures were similarly correlated to the submerged mussel logger temperatures. This finding suggests that satellite-derived SSTs may be used in conjunction with local water temperatures to understand the temporal and spatial variation of mussel logger temperatures. While there are limitations to using satellite-derived temperature for ecological studies, including issues with temporal and spatial resolution, our results are promising.

Similar temperature dependencies of glycolytic enzymes: an evolutionary adaptation to temperature dynamics?

Directory of Open Access Journals (Sweden)

Cruz Luisa Ana B

2012-12-01

Full Text Available Abstract Background Temperature strongly affects microbial growth, and many microorganisms have to deal with temperature fluctuations in their natural environment. To understand regulation strategies that underlie microbial temperature responses and adaptation, we studied glycolytic pathway kinetics in Saccharomyces cerevisiae during temperature changes. Results Saccharomyces cerevisiae was grown under different temperature regimes and glucose availability conditions. These included glucose-excess batch cultures at different temperatures and glucose-limited chemostat cultures, subjected to fast linear temperature shifts and circadian sinoidal temperature cycles. An observed temperature-independent relation between intracellular levels of glycolytic metabolites and residual glucose concentration for all experimental conditions revealed that it is the substrate availability rather than temperature that determines intracellular metabolite profiles. This observation corresponded with predictions generated in silico with a kinetic model of yeast glycolysis, when the catalytic capacities of all glycolytic enzymes were set to share the same normalized temperature dependency. Conclusions From an evolutionary perspective, such similar temperature dependencies allow cells to adapt more rapidly to temperature changes, because they result in minimal perturbations of intracellular metabolite levels, thus circumventing the need for extensive modification of enzyme levels.

A survey of temperature measurement

International Nuclear Information System (INIS)

Saltvold, J.R.

1976-03-01

Many different techniques for measuring temperature have been surveyed and are discussed. The concept of temperature and the physical phenomena used in temperature measurement are also discussed. Extensive tables are presented in which the range and accuracy of the various techniques and other related data are included. (author)

Solvated electrons at elevated temperatures in different alcohols: Temperature and molecular structure effects

Energy Technology Data Exchange (ETDEWEB)

Yan, Yu [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Lin, Mingzhang [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.j [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Fu, Haiying; Muroya, Yusa [Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan)

2010-12-15

The absorption spectra of solvated electrons in pentanol, hexanol and octanol are measured from 22 to 200, 22 to 175 and 50 to150 {sup o}C, respectively, at a fixed pressure of 15 MPa, using nanosecond pulse radiolysis technique. The results show that the peak positions of the absorption spectra have a red-shift (shift to longer wavelengths) as temperature increases, similar to water and other alcohols. Including the above mentioned data, a compilation of currently available experimental data on the energy of absorption maximum (E{sub max}) of solvated electrons changed with temperature in monohydric alcohols, diols and triol is presented. E{sub max} of solvated electron is larger in those alcohols that have more OH groups at all the temperatures. The molecular structure effect, including OH numbers, OH position and carbon chain length, is investigated. For the primary alcohols with same OH group number and position, the temperature coefficient increases with increase in chain length. For the alcohols with same chain length and OH numbers, temperature coefficient is larger for the symmetric alcohols than the asymmetric ones.

Is Oral Temperature an Accurate Measurement of Deep Body Temperature? A Systematic Review

Science.gov (United States)

Mazerolle, Stephanie M.; Ganio, Matthew S.; Casa, Douglas J.; Vingren, Jakob; Klau, Jennifer

2011-01-01

Context: Oral temperature might not be a valid method to assess core body temperature. However, many clinicians, including athletic trainers, use it rather than criterion standard methods, such as rectal thermometry. Objective: To critically evaluate original research addressing the validity of using oral temperature as a measurement of core body temperature during periods of rest and changing core temperature. Data Sources: In July 2010, we searched the electronic databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTDiscus, Academic Search Premier, and the Cochrane Library for the following concepts: core body temperature, oral, and thermometers. Controlled vocabulary was used, when available, as well as key words and variations of those key words. The search was limited to articles focusing on temperature readings and studies involving human participants. Data Synthesis: Original research was reviewed using the Physiotherapy Evidence Database (PEDro). Sixteen studies met the inclusion criteria and subsequently were evaluated by 2 independent reviewers. All 16 were included in the review because they met the minimal PEDro score of 4 points (of 10 possible points), with all but 2 scoring 5 points. A critical review of these studies indicated a disparity between oral and criterion standard temperature methods (eg, rectal and esophageal) specifically as the temperature increased. The difference was −0.50°C ± 0.31°C at rest and −0.58°C ± 0.75°C during a nonsteady state. Conclusions: Evidence suggests that, regardless of whether the assessment is recorded at rest or during periods of changing core temperature, oral temperature is an unsuitable diagnostic tool for determining body temperature because many measures demonstrated differences greater than the predetermined validity threshold of 0.27°C (0.5°F). In addition, the differences were greatest at the highest rectal temperatures. Oral temperature cannot

7 CFR 51.3741 - U.S. Commercial.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. Commercial. 51.3741 Section 51.3741 Agriculture... 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...

Comparison of slant-path scintillometry, sonic anemometry and high-speed videography for vertical profiling of turbulence in the atmospheric surface layer

CSIR Research Space (South Africa)

Griffith, DJ

2013-09-01

Full Text Available -zero temperatures were encountered after 00:00 UTC on occasion with formation of some fog, dew or frost. Winds were predominantly from the southerly direction at night and north-westerly direction during the day. The wind changeover times were about 07:00 UTC and 17...:00 UTC. The wind statistics and wind run over the period 23 to 29 June, 2013 are given in Figure 6. The wind run has a characteristic diurnal sawtooth shape, but strongly dominated by the day-period westerly component. Mean night-period (17:00 to 07...

Managing Temperature Effects in Nanoscale Adaptive Systems

CERN Document Server

Wolpert, David

2012-01-01

This book discusses new techniques for detecting, controlling, and exploiting the impacts of temperature variations on nanoscale circuits and systems.  It provides a holistic discussion of temperature management, including physical phenomena (reversal of the MOSFET temperature dependence) that have recently become problematic, along with circuit techniques for detecting, controlling, and adapting to these phenomena. A detailed discussion is also included of the general aspects of thermal-aware system design and management of temperature-induced faults. A new sensor system is described that can determine the temperature dependence as well as the operating temperature to improve system reliability.  A new method is presented to control a circuit’s temperature dependence by individually tuning pull-up and pull-down networks to their temperature-insensitive operating points. This method extends the range of supply voltages that can be made temperature-insensitive, achieving insensitivity at nominal voltage fo...

High temperature materials and mechanisms

CERN Document Server

2014-01-01

The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...