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A Photoelectric Hygrometer

Description: Note presenting an instrument that measures small absolute humidity changes by photoelectric examination of the 9440 angstrom units absorption band of water vapor. The instrument consists of a small source of light which sends its radiation over an air path of less than 1.5 meters to a dispersing system.
Date: May 1945
Creator: Hamermesh, Bernard; Reines, Frederick & Korff, Serge A.
Partner: UNT Libraries Government Documents Department

An Approximate Method of Calculation of Relative Humidity Required to Prevent Frosting on Inside of Aircraft Pressure Cabin Windows, Special Report

Description: This report has been prepare in response to a request for information from an aircraft company. A typical example was selected for the presentation of an approximate method of calculation of the relative humidity required to prevent frosting on the inside of a plastic window in a pressure type cabin on a high speed airplane. The results of the study are reviewed.
Date: December 5, 1940
Creator: Jones, Alun R.
Partner: UNT Libraries Government Documents Department

The Effect of Humidity on Engine Power at Altitude

Description: "From tests made in the altitude chamber of the Bureau of Standards, it was found that the effect of humidity on engine power is the same at altitudes up to 25,000 feet as at sea level. Earlier tests on automotive engines, made under sea-level conditions, showed that water vapor acts as an inert diluent, reducing engine power in proportion to the amount of vapor present. By combining the effects of atmospheric pressure, temperature, and humidity, it is shown that the indicated power obtainable from an engine is proportional to its mass rate of consumption of oxygen" (p. 523).
Date: February 24, 1932
Creator: Brooks, D. B. & Garlock, E. A.
Partner: UNT Libraries Government Documents Department

Correcting Engine Tests for Humidity

Description: Note presenting tests using a multicylinder engine to determine the effect that atmospheric humidity has on some phases of engine performance. Three test series with different types of fuel were carried out. The results indicate that failure to allow for the effect of differences in atmospheric humidity may introduce errors as great as would be occasioned by failure to allow for changes in barometric pressure.
Date: June 1929
Creator: Brooks, Donald B.
Partner: UNT Libraries Government Documents Department

The Humidity of Mine Air with Especial Reference to Coal Mines in Illinois

Description: From Introduction: "The investigative work described in this report was undertaken by the Bureau of Mines under a cooperative agreement with the department of mining engineering of the University of Illinois and the Illinois and Illinois State Geological Survey. The purpose of this agreement was to provide for a comprehensive investigation of coal-mining conditions in the State, with especial reference to the possibility of lessening waste in the mining and preparation of coal and of reducing the dangers to which miners are exposed. Thus, it studied the occurrence of gas (methane) in the mines of the southern part of the State, tested the inflammability of the coal dust from many mines, examined the efficiency of the control of ventilating currents, and investigated the factors affecting the humidity of mine air with respect to their bearing on the occurrence of mine explosions."
Date: 1914
Creator: Williams, R. Y.
Partner: UNT Libraries Government Documents Department

Forest Products: Acoustic Humidity Sensor

Description: The new acoustic sensor, designed as a humidity-control system for the paper and textile industries, can both eliminate overdrying and improve product quality by measuring humidity precisely. This new fact sheet explains how the process works.
Date: January 29, 1999
Creator: Poole, L. & Recca, L.
Partner: UNT Libraries Government Documents Department

Effect of Humidity on Performance of Turbojet Engines

Description: Report presenting an experimental and analytical investigation to determine the effect of humidity on turbojet-engine performance. The humidity effect was found to be very small with the magnitude depending on the basis of comparison. Results regarding the calculated humidity correction factors, experimental effect of humidity of engine performance, and variation of saturation specific humidity with altitude are provided.
Date: June 1950
Creator: Samuels, John C. & Gale, B. M.
Partner: UNT Libraries Government Documents Department

A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

Description: The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.
Date: October 1, 2010
Creator: Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L & Apte, Michael G.
Partner: UNT Libraries Government Documents Department

Identification of random variation in structures and their parameter estimates.

Description: Structures that are members of an ensemble of nominally identical systems actually differ due to variations in details among individuals. Furthermore, there are variations in the system response of an individual structure that can be attributed to unmeasured conditions (such as temperature and humidity) that are present during experiments. Finally, noise is present in all measurements of structural excitations and responses. For these reasons, there is always random variation associated with the characterizations of structural dynamic systems, and descriptions of results must be in statistical or probabilistic terms;. This study identifies and assesses the sources and the degrees of randomness in a metric of structural dynamics of a given system through experiments and analysis.
Date: January 1, 2002
Creator: Farrar, C. R. (Charles R.); Aumann, R. J. (Richard J.); McCarty, A. A. (Amanda A.) & Olson, C. C. (Colin C.)
Partner: UNT Libraries Government Documents Department

Apparent Multi-Decadal Trend in Shortwave Cloud Forcing Over the Tropical Pacific

Description: The NCEP/NCAR reanalysis (Kalnay et al. 1996) of atmospheric data beginning in 1948 has provided an opportunity to study a consistent half-century record of assimilated weather observations. Through the examination of several fields, we find an apparent long-term decrease in relative humidity, and hence a decrease in inferred cloud amount, in a large region in the central tropical Pacific. As a result, the apparent short-wave cloud radiative forcing in that region decreased by nearly 15 Wm{sup -2} Over the duration of the period. Two major questions arise from these preliminary results. The first question involves the extent to which the apparent trend over the 50-year period is a real phenomenon rather than an artifact, either of the reanalysis methodology or of observing system evolution. The second question is, if the phenomenon is not entirely an artifact, but is at least partially real, what is its cause?
Date: October 3, 2000
Creator: Somerville, R C J; Potter, G L; Kanamitsu, M; Hnilo, J J & Woolen, J
Partner: UNT Libraries Government Documents Department

Range Energy Relation for Protons in Nuclear Emulsions

Description: An experimental range-energy relation in Ilford C-2 emulsion has been obtained for proteins up to 39.5 Mev. In the region from 17 to 33 Mev the relation for dry emulsion is fitted by the empirical equation E{sub (MeV)} = 0.251 R{sub ({mu})} 0.581. Variations in water content due to changes in atmospheric humidity make several percent difference in range. The range in Ilford glass is found to be 18 {+-} 4 percent longer than in dry C-2 emulsion.
Date: September 9, 1949
Creator: Bradner, H.; Smith, F.M.; Barkas, W.H. & Bishop, A.S.
Partner: UNT Libraries Government Documents Department

Use of organic solderability preservatives on solderability retention of copper after accelerated aging

Description: Organic solderability preservatives (OSP`s) have been used by the electronics industry for some time to maintain the solderability of circuit boards and components. Since solderability affects both manufacturing efficiency and product reliability, there is significant interest in maintaining good solder wettability. There is often a considerable time interval between the initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, in many cases not well controlled. Solder wettability can deteriorate during storage, especially in harsh environments. This paper describes the ongoing efforts at Sandia National Laboratories to quantify solder watability on bare and aged copper surfaces. Benzotriazole and imidazole were applied to electronic grade copper to retard aging effects on solderability. The coupons were introduced into Sandia`s Facility for Atmospheric Corrosion Testing (FACT) to simulate aging in a typical indoor industrial environment. H{sub 2}S, NO{sub 2} and Cl{sub 2} mixed gas was introduced into the test cell and maintained at 35{degrees}C and 70% relative humidity for test periods of one day to two weeks. The OSP`s generally performed better than bare Cu, although solderability diminished with increasing exposure times.
Date: February 1, 1997
Creator: Hernandez, C.L.; Sorensen, N.R. & Lucero, S.J.
Partner: UNT Libraries Government Documents Department

The Influence of Coating Structure on Micromachine Stiction

Description: We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.
Date: October 3, 2000
Creator: Kushmerick, J. G.; Hankins, M. G.; De Boer, M. P.; Clews, P. J.; Carpick, R. W. & Bunker, B. C.
Partner: UNT Libraries Government Documents Department


Description: With the recent creation of the PX HE Core Surveillance Database, individual specimen surveillance values can be easily compared to the corresponding individual qualification values to evaluate for trends. A review of the data shows a broad scatter in measured stress-strain values. Using the available HE surveillance database, it is clear that the surveillance measurements from the two Cycle 15 charges fall within the range of qualification stress and strain values recorded previously for PBX 9502 lots and that no apparent stockpile-age related trends are evident in the tensile stress-strain data. As a result of this investigation, some changes are being made to the core surveillance specifications to minimize the effects on tensile data scatter due to temperature and humidity differences and method to method changes. These data analyses do point out the need for a comprehensive understanding of the effect of a number of variables, i.e. formulation and pressing method, density, stockpile age, lot-to-lot variations, temperature, and humidity on the mechanical property behavior of HE composite materials. Too often data have been compared without the relevant details made available to determine if the test conditions were nominally the same or different. These results also point out the critical need to establish useful stress-strain limits for qualification and surveillance testing of HEs.
Date: October 1, 2000
Creator: Idar, D.J. & Larson, S.A.
Partner: UNT Libraries Government Documents Department

Incubation humidity as an environmental stressor on the osmoregulatory developmental program of the chicken, Gallus gallus domesticus.

Description: Fetal programming results from stressors during fetal development and may influence the occurrence of disease later in life. Maternal nutritional status and/or environment can affect renal development by inducing limited nephron endowment at birth, which results in diseases such as hypertension and coronary heart disease in mammals. Birds are likely to be effective models for this process because, like mammals, they have high pressure cardiovascular systems, mammalian-type nephrons and are homeothermic. This project uses the chicken embryo to explore physiological responses of disrupted hydration state thereby providing insights into renal fetal programming. Under normal conditions the chorioallantoic membrane (CAM) and developing avian kidney work in unison to ensure a proper balance of ions and water within the egg. White leghorn chicken eggs were incubated at 37.5oC±0.5oC and either <35%, 55-60% (normal) or >85% relative humidity. Amniotic fluid serves as the drinking source for the embryo late in development; its composition is important to salt and water homeostasis. High amniotic fluid osmolality increased the blood osmolality for embryos exposed to low humidity incubation thereby indirectly influencing the renal developmental program of the embryos from this group. Indeed estimated filtering capacity was doubled in the low humidity group (6.77 ± 0.43 mm3) compared to normal (4.80 ± 0.33 mm3) and high (3.97 ± 0.30 mm3) humidity groups. The increased filtering capacity seen for those embryos from low humidity may indicate the ability for more efficient recovery of water if similarly stressed as an adult bird. All embryo populations maintained similar oxygen consumption (0.075 ml/min - 0.37 ml/min), hematocrit (15 % - 32 %) and hemoglobin values (4 g/dl - 9 g/dl), thus displaying control over these aspects of the internal environment despite the obvious environmental insult of extreme incubation humidity. These results signify the embryo's immature kidney, along with lower gastrointestinal tract, ...
Date: August 2009
Creator: Bolin, Greta M.
Partner: UNT Libraries

Atmospheric Corrosion of batten and Enclosure Materials for Flat-Plate Solar Collectors

Description: As part of the Solar Reliability and Materials Program at Argonne National Laboratory, the atmospheric corrosion of candidate batten and enclosure materials were tested on outdoor racks parallel to the tilted solar-collected panels at nine National Solar Data Network (NSDN) sites, located in mild marine, mild industrial, and rural environments. The candidate materials evaluated include galvanized steel (G-90), aluminized steel (Type 2), aluminum (6061), and white polyester painted steel. Data analyses predicted that all the first three materials will last more than 20 years in the nine sites tested. However, repainting of the painted steel is probably needed within five years in a mild marine environment and five to ten years in a mild industrial or rural environment.
Date: April 1983
Creator: Cheng, Craig F.
Partner: UNT Libraries Government Documents Department


Description: Tests are described to determine the amount of entrained moisture occurring in the steam of the Pathfinder Power Plant as design parameters were varied. It was found that the height of the moisture separator and the velocity of the steam should be adjusted so that the permissible steam velocity for the particular height is not exceeded. If this is done, the amount of moisture entering the separator should be less than 1%, an amount of moisture that should not be difficult to remove with moisture separators. (J.R.D.)
Date: November 15, 1959
Creator: Wilson, J. & McDermott, M.
Partner: UNT Libraries Government Documents Department

Diagnosing causes of cloud parameterization deficiencies using ARM measurements over SGP site

Description: Decade-long continuous surface-based measurements at Great Southern Plains (SGP) collected by the US Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility are first used to evaluate the three major reanalyses (i.e., ERA-Interim, NCEP/NCAR Reanalysis I and NCEP/DOE Reanalysis II) to identify model biases in simulating surface shortwave cloud forcing and total cloud fraction. The results show large systematic lower biases in the modeled surface shortwave cloud forcing and cloud fraction from all the three reanalysis datasets. Then we focus on diagnosing the causes of these model biases using the Active Remote Sensing of Clouds (ARSCL) products (e.g., vertical distribution of cloud fraction, cloud-base and cloud-top heights, and cloud optical depth) and meteorological measurements (temperature, humidity and stability). Efforts are made to couple cloud properties with boundary processes in the diagnosis.
Date: March 15, 2010
Creator: Wu, W.; Liu, Y. & Betts, A. K.
Partner: UNT Libraries Government Documents Department

Tower Temperature and Humidity Sensors (TWR) Handbook

Description: Three tall towers are installed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility: a 60-meter triangular tower at the Southern Great Plains (SGP) Central Facility (CF), a 21-meter walkup scaffolding tower at the SGP Okmulgee forest site (E21), and a 40-meter triangular tower at the North Slope of Alaska (NSA) Barrow site. The towers are used for meteorological, radiological, and other measurements.
Date: February 1, 2010
Creator: Cook, DR
Partner: UNT Libraries Government Documents Department