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Plastics as structural materials for aircraft

Description: The purpose here is to consider the mechanical characteristics of reinforced phenol-formaldehyde resin as related to its use as structural material for aircraft. Data and graphs that have appeared in the literature are reproduced to illustrate the comparative behavior of plastics and materials commonly used in aircraft construction. Materials are characterized as to density, static strength, modulus of elasticity, resistance to long-time loading, strength under repeated impact, energy absorption, corrosion resistance, and ease of fabrication.
Date: December 1937
Creator: Kline, G. 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

Collision Broadening in the Microwave Rotational Spectrum of Gaseous Monomeric Formaldehyde

Description: A source-modulation microwave spectrograph was utilized to measure line width parameters for several spectral lines in the pure rotational spectrum of formaldehyde (H₂CO). The spectrograph featured high-gain ac amplification and phase-sensitive detection, and was capable of measuring microwave lines having absorption coefficients as small as 10⁻⁷ cm⁻¹ with a frequency resolution on the order of 30 kHz. Center frequencies of the measured lines varied from 4,830 MHz to 72,838 MHz; hence, most of the observations were made on transitions between K-doublets in the rotational spectrum. Corrections were applied to the measured line width parameters to account for Doppler broadening and, where possible, for deviations due to magnetic hyperfine structure in some of the K-doubled lines. Low modulation voltages and low microwave power levels were used to minimize modulation and saturation broadenings; other extraneous broadenings were found to be insignificant. The primary broadening mechanism at low gas pressure is pressure broadening, and a review of this topic is included. Line width parameters for the several observed transitions were determined by graphing half-widths versus pressure for each spectral line, and performing a linear least-squares fit to the data points. Repeatability measurements indicated the accuracy of the line width parameters to be better than ±10 percent. The reasons for this repeatability spread are discussed, Broadening of each line was measured for self- and foreign-gas broadening by atomic helium and diatomic hydrogen. Effective collision diameters were calculated for each broadening interaction, based on the observed rates of broadening.
Date: December 1973
Creator: Rogers, David Valmore
Partner: UNT Libraries


Description: The LBL formaldehyde sampler consists of two parts: 1) a pump box and 2) a small refrigerator housing sampling bubblers. The pump box contains two pumps, a timer, a flow controller, an electrical cord, and a ten-foot piece of tubing to connect the refrigerator to the pump box. The small refrigerator contains four columns of bubbler sampling trains attached to a metal plate. Two sampling trains each are plumbed in parallel to two sampling ports on the back of the refrigerator. The two sampling lines supplied are to be attached to these ports to allow two locations to be sampled at once (usually one indoor and one outdoor). The refrigerator also contains a rack for holding bubbler tubes. In the sampling process, air is drawn through a sampling line attached to the fitting at the back of the refrigerator and into a prlmary bubbler containing a trapping solution. This trapping solution can be distilled water or an aqueous solution of some compound that reacts with formaldehyde. From this bubbler the air goes through a second bubbler containing the same trapping solution as the first bubbler. (To maintain sample integrity, all parts that the air sample contacts are made of Teflon, polypropylene, and stainless steel.) The air then goes into the third bubbler, which contains no liquid. This bubbler contains a hypodermic needle that serves as a flow-control orifice. The hypodermic needle, in conjunction with the flow controller in the pump box, ensures a constant a flow rate. The refrigerator contains four columns of these sets of three bubblers. After samples have been collected, the bubbler bottoms are detached and the contents of the first and second bubblers in each column are poured together, capped, and labeled. The use of a refrigerated primary and secondary bubbler whose contents are combined at ...
Date: September 1, 1981
Creator: Fanning, L.Z.; Allen, J.R. & Miksch, R.R.
Partner: UNT Libraries Government Documents Department


Description: Analytical methods for determining formic and oxalic acids, formaldehyde and methanol have been evaluated and/or optimized for measuring products from photoreduction of CO{sub 2} in illuminated, aqueous suspensions of photocatalysts. An electrophoretic analysis method can detect aqueous formate and oxalate ions at 3 and 1 {micro}M respectively. Recalibration of the Nash formaldehyde determination shows that as little as 0.5 {micro}M can be detected spectrally. Several experiments using suspensions of TiO{sub 2}, SrTiO{sub 3} and SrTiO{sub 3} with Cr and Sb were tested in CO{sub 2} saturated solutions. No formate was detected in most experiments. However adding 2-propanol to a CO{sub 2}/TiO{sub 2} suspension gave significant amounts of formate and some formaldehyde by blocking the re-oxidation of formate by semiconductor holes. Loss of C{sub 1} products by re-oxidation is probably an important process limiting the accumulation of formate, formaldehyde and methanol.
Date: March 13, 2003
Creator: Mill, Theodore & Tungudomwongsa, Haruthai
Partner: UNT Libraries Government Documents Department

Near Degenerate Rearrangement Between the Radical Cations of Formaldehyde and Hydroxymethylene

Description: Motivated by the recent experiments of Berkowitz, a systematic theoretical study of the ion isomerization H{sub 2}CO{sup +} {yields} HCOH{sup +} has been carried out. Structures and vibrational frequencies for H{sub 2}CO{sup +}, the transition state, and the cis and trans isomers of HCOH{sup +} have been determined at the double zeta basis set self-consistent-field (SCF) level of theory. Equilibrium geometries were also predicted from SCF theory using a double zeta plus polarization (DZ+P) basis set. Final energetics were pinned down using DZ+P configuration interaction, involving a total of 16,290 configurations. The most reliable theoretical results suggest that trans-HCOH{sup +} lies 5.5 kcal above H{sub 2}CO{sup +}. Zero-point vibrational energy corrections do not change this H{sub 2}CO{sup +}-HCOH{sup +} separation. Similarly cis-HCOH{sup +} is predicted to lie 4.1 kcal above the trans isomer, and the barrier to rotation between the two HCOH{sup +} isomers is -18 kcal. The barrier to H{sub 2}CO{sup +} {yields} HCOH{sup +} rearrangement is predicted to be 49.0 kcal, or 44.4 kcal after correction for zero-point vibrational energies is made. The relationship between this cationic 1,2-hydrogen shift and the corresponding neutral rearrangement is discussed in terms of qualitative molecular orbital theory.
Date: June 1, 1980
Creator: Osamura, Y.; Goddard, J.D.; Schaefer III, H.F. & Kim, K.S.
Partner: UNT Libraries Government Documents Department

Fire Safety Tests for Cesium-Loaded Spherical Resorcinol Formaldehyde Resin: Data Summary Report

Description: A draft safety evaluation of the scenario for spherical resorcinol formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI) through a subcontract managed by Pacific Northwest National Laboratory (PNNL). The results of initial fire safety tests on the SRF resin were documented in a previous report (WTP-RPT-218). The present report summarizes the results of additional tests performed by SwRI on the cesium-loaded SRF resin. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. The as-received SwRI report is attached to this report in the Appendix A. Where applicable, the precision and bias of each test method, as given by each American Society for Testing and Materials (ASTM) standard procedure, are included and compared with the SwRI test results of the cesium-loaded SRF resin.
Date: September 1, 2012
Creator: Kim, Dong-Sang; Schweiger, Michael J. & Peterson, Reid A.
Partner: UNT Libraries Government Documents Department

Using Data Fusion to Characterize Breast Tissue

Description: New ultrasound data, obtained with a circular experimental scanner, are compared with data obtained with standard X-ray CT. Ultrasound data obtained by scanning fixed breast tissue were used to generate images of sound speed and reflectivity. The ultrasound images exhibit approximately 1 mm resolution and about 20 dB of dynamic range. All data were obtained in a circular geometry. X-ray CT scans were used to generate X-ray images corresponding to the same 'slices' obtained with the ultrasound scanner. The good match of sensitivity, resolution and angular coverage between the ultrasound and X-ray data makes possible a direct comparison of the three types of images. We present the results of such a comparison for an excised breast fixed in formalin. The results are presented visually using various types of data fusion. A general correspondence between the sound speed, reflectivity and X-ray morphologies is found. The degree to which data fusion can help characterize tissue is assessed by examining the quantitative correlations between the ultrasound and X-ray images.
Date: January 23, 2002
Creator: Littrup, P; Duric, N; Leach, R R; Azevedo, S G; Candy, J V; Moore, T et al.
Partner: UNT Libraries Government Documents Department

Collision Broadening of Microwave Spectral Lines of Monomeric Formaldehyde and Formic Acid

Description: Line width parameters for a number of spectral lines in the pure rotational spectrum of formaldehyde (CH20) and formic acid (HCOOH) have been measured using a sourcemodulated microwave spectrograph. All transitions studied in this investigation were of the type ΔJ=O (i.e. Q-branch transitions), with ΔK-1=0 and ΔK+1 =+l. The center frequencies of the measured lines varied from 8662.0 MHz to 48612.70 MHz. The experimentally determined collision diameters for self broadening interactions involving HCOOH and CH2 Q molecules were found to be 2 - 27 per cent less than those calculated by the Murphy-Boggs theory of collision broadening. Much better agreement between a simplified broadening scheme for symmetric top molecules and the observed foreign-gas collision diameters is obtained by using Birnbaum's theory.
Date: August 1975
Creator: Venkatachar, Arun C.
Partner: UNT Libraries

Formaldehyde as a basis for residential ventilation rates

Description: Traditionally, houses in the U.S. have been ventilated by passive infiltration in combination with active window opening. However in recent years, the construction quality of residential building envelopes has been improved to reduce infiltration, and the use of windows for ventilation also may have decreased due to a number of factors. Thus, there has been increased interest in engineered ventilation systems for residences. The amount of ventilation provided by an engineered system should be set to protect occupants from unhealthy or objectionable exposures to indoor pollutants, while minimizing energy costs for conditioning incoming air. Determining the correct ventilation rate is a complex task, as there are numerous pollutants of potential concern, each having poorly characterized emission rates, and poorly defined acceptable levels of exposure. One ubiquitous pollutant in residences is formaldehyde. The sources of formaldehyde in new houses are reasonably understood, and there is a large body of literature on human health effects. This report examines the use of formaldehyde as a means of determining ventilation rates and uses existing data on emission rates of formaldehyde in new houses to derive recommended levels. Based on current, widely accepted concentration guidelines for formaldehyde, the minimum and guideline ventilation rates for most new houses are 0.28 and 0.5 air changes per hour, respectively.
Date: April 28, 2002
Creator: Sherman, M.H. & Hodgson, A.T.
Partner: UNT Libraries Government Documents Department

Microbial Formaldehyde Oxidation

Description: This project analyzed how cells sense and generate energy from formaldehyde oxidation. Formaldehyde is a toxin that is produced naturally, chemically or by metabolism of a wide variety of methyl-containing compounds. Our goals are to identify how cells sense the presence of this toxic compound and determine how they generate energy and nutrients from the oxidation of formaldehyde. This research capitalizes on the role of the Rhodobacter sphaeroides glutathione dependent formaldehyde dehydrogenase (GSH FDH) in a formaldehyde oxidation pathway that is apparently found in a wide variety of microbes, plants and animals. Thus, our findings illustrate what is required for a large variety of cells to metabolize this toxic compound. A second major focus of our research is to determine how cells sense the presence of this toxic compound and control the expression of gene products required for its detoxification.
Date: December 9, 2004
Creator: Donohue, Timothy J.
Partner: UNT Libraries Government Documents Department

A density functional theory study of the oxidation of methanol to formaldehyde over vanadia supported on silica, titania, and zirconia

Description: Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO{sub 4} unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 10{sup 3} greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO{sub 4} groups or V{sub 2}O{sub 7} dimer structures.
Date: September 5, 2002
Creator: Khaliullin, Rustam Z. & Bell, Alexis T.
Partner: UNT Libraries Government Documents Department

Predicted concentrations in new relocatable classrooms of volatile organic compounds emitted from standard and alternate interior finish materials

Description: Relocatable classrooms (RCs) are widely employed by California school districts to satisfy rapidly expanding space requirements due to population growth and class size reduction policies. There is public concern regarding indoor environmental quality (IEQ) in schools, particularly in RCs, but very little data to support or dispel these concerns. Several studies are investigating various aspects of IEQ in California schools. This laboratory-based study focused on evaluating the emissions of toxic and/or odorous volatile organic compounds (VOCs), including formaldehyde and acetaldehyde, from materials used to finish the interiors of new RCs. Furthermore, the study implemented a procedure for VOC source reduction by testing and selecting lower-emitting materials as substitutes for standard materials. In total, 17 standard and alternate floor coverings, wall panels and ceiling panels were quantitatively tested for emissions of VOCs using smallscale environmental chambers. Working with the largest northern California manufacturer of conventional RCs and two school districts, specifications were developed for four new RCs to be produced in early summer 2001. Two of these will be predominantly finished with standard materials. Alternate carpet systems, an alternate wall panel covering and an alternate ceiling panel were selected for the two other RCs based on the results of the laboratory study and considerations of cost and anticipated performance and maintenance. Particular emphasis was placed on reducing the concentrations of VOCs on California agency lists of toxic compounds. Indoor concentrations of toxic and odorous VOCs were estimated for the four classrooms by mass balance using the measured VOC emission factors, exposed surface areas of the materials in the RCs, and three ventilation rate scenarios. Results indicate that reductions in the concentrations of formaldehyde, acetaldehyde phenol, di(ethylene glycol) butyl ether, vinyl acetate, 1,2,4-trimethylbenzene and 1-methyl-2-pyrrolidinone should be achieved as the result of the source reduction procedure.
Date: July 1, 2001
Creator: Hodgson, Alfred T.; Fisk, William J.; Shendell, Derek G. & Apte, Michael G.
Partner: UNT Libraries Government Documents Department

Resorcinol-formaldehyde and carbon aerogel microspheres

Description: Aerogels are a unique class of materials possessing an open-cell structure with ultrafine cells/pores (<100nm), high surface area (400--1100 m{sup 2}/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10nm. Although monolithic aerogels are ideal candidates for many applications (e.g. transparent window insulation), current processing methods have limited their introduction into the commercial marketplace. Our research focuses on the formation of resorcinol-formaldehyde (RF) aerogel microspheres which offer an attractive alternative to monolith production. An inverse emulsion polymerization is used to produce these spherical gel particles which undergo solvent exchange followed by supercritical drying with carbon dioxide. This process yields aerogel microspheres (10--80{mu} diameter) which can be used as loosely packed powders, compression molded into near-net shapes using a polymer binder, or used as additives in conventional foaming operations to produce new aerogel composites with superior thermal properties. The emulsification procedure, thermal characterization, mechanical properties, and potential applications of RF aerogel microspheres will be discussed.
Date: April 1996
Creator: Alviso, C. T.; Pekela, R. W.; Gross, J.; Lu, X.; Caps, R. & Fricke, J
Partner: UNT Libraries Government Documents Department

Experimental and theoretical investigation of the product channels of the O + CH{sub 3} reaction

Description: The product channels of the O({sup 3}P)+CH{sub 3} reaction was investigated. In the experimental part, the branching fraction for formaldehyde production (O+CH{sub 3}{r_arrow}H{sub 2}CO+H) was measured at room temperature in a tubular flow reactor coupled to a photoionization mass spectrometer. The reactants (CH{sub 3} and O) were generated homogeneously in the reactor by simultaneous {ital in}{ital situ} 193-nm photolysis of acetone and SO{sub 2}. Formaldehyde yield relative to the methyl radicals consumed (branching fraction) was determined to be 1.0{+-}0.15. In the theoretical part, calculations of the energetics of possible decomposition pathways of the energy-rich methoxy radical initially formed in the O+CH{sub 3} reaction indicate that the dominant channel for decomposition is C-H bond cleavage leading to atomic hydrogen and formaldehyde. A possible, minor, secondary channel is hydrogen migration, followed by O-H bond cleavage, leading to the same final products. No energetically competitive pathways leading to H{sub 2}, HCO, HOC, or CO could be found.
Date: May 1, 1994
Creator: Slagle, I.R.; Kalinovski, I.J.; Gutman, D. & Harding, L.B.
Partner: UNT Libraries Government Documents Department

Rate constants for H{sub 2}CO + O{sub 2} {yields} HCO + HO{sub 2} at high temperature

Description: The reaction between H{sub 2}CO and O{sub 2} has been studied in a reflected shock tube apparatus between 1633--2027 K using trioxane, (H{sub 2}CO){sub 3}, as the source of H{sub 2}CO. O-atom atomic resonance absorption spectrometry (ARAS) was used to observe absolute [O]{sub t} under conditions of low [H{sub 2}CO]{sub 0} so that most secondary reactions were negligible. Hence, the observed [O]{sub t} was the direct result of the rate controlling reaction between H{sub 2}CO and O{sub 2}. Ab initio theoretical results indicated that the process, H{sub 2}CO + O{sub 2} {yields} HCO + HO{sub 2}, is the only possible reaction. After rapid HCO and HO{sub 2} dissociations, O-atoms are then instantaneously produced from H + O{sub 2} {yields} O + OH. Using the ab initio result, variational transition state theoretical calculations (CTST) give k{sub 1} = 4.4929 x 10{sup {minus}20} T{sup 2.9116} exp{minus}18692/T cm{sup 3} molecule{sup {minus}1} S{sup {minus}1}. This theoretical result is consistent with the present experimental determinations and those at lower temperatures.
Date: January 5, 2000
Creator: Michael, J. V.; Su, M.-C.; Sutherland, J. W.; Fang, D.-C.; Harding, L. B. & Wagner, A. F.
Partner: UNT Libraries Government Documents Department

Hanford tank waste supernatant cesium removal test plan

Description: This document provides the test plan for the preparation and conduct of a cesium removal test using Hanford DSSF supernatant liquor from tank 241-AW-101 in a bench-scale column. Cesium sorbents to be tested include resorcinol-formaldehyde resin and crystalline silicotitanate.
Date: May 31, 1996
Creator: Hendrickson, D.W., Westinghouse Hanford
Partner: UNT Libraries Government Documents Department

The origin of hydrogen generated from formaldehyde in basic solutions

Description: The isotopic composition of dihydrogen generated from formaldehyde in highly basic solutions has been investigated. It is shown that two pathways contribute to the generation of dihydrogen. In the first pathway, one hydrogen atom originates from water and the other from formaldehyde. In the second pathway both hydrogen atoms originate from the methylene moiety of the formaldehyde. For production of dihydrogen from glyoxylate only the first pathway is observed.
Date: March 1, 1996
Creator: Kapoor, S.; Barnabas, F.; Jonah, C.D.; Sauer, M.C. Jr. & Meisel, D.
Partner: UNT Libraries Government Documents Department

Some Common Disinfectants

Description: "There is much popular misconception as to the value and limitations of the various disinfectants which are sold in this country. For this reason the following very brief description of some of the more common of them has been prepared." -- p. 5. Chemicals discussed include formaldehyde, carbolic acid, cresol, chlorinated lime, and bichloride of mercury.
Date: 1908
Creator: Dorset, M. (Marion)
Partner: UNT Libraries Government Documents Department

Formaldehyde in Textiles: While Levels in Clothing Generally Appear to Be Low, Allergic Contact Dermatitis Is a Health Issue for Some People

Description: A letter report issued by the Government Accountability Office with an abstract that begins "Formaldehyde--one of the most widely produced chemicals in the world--is used in many products, including disinfectants, pressed-wood, and clothing and other textiles. Exposure to this chemical, which has been linked to adverse health effects for more than 30 years, typically occurs through inhalation and dermal (skin) contact. Formaldehyde can be used to enhance wrinkle resistance in some clothing and textiles, especially those made of cotton. The Consumer Product Safety Commission reviewed formaldehyde in clothing in the 1980s and determined that the levels found did not pose a public health concern. At that time, most clothing sold in the United States was made here--but the market has changed such that most U.S. clothing is now made in other countries. This market change has raised anew questions about the levels of formaldehyde in clothing. In response to a mandate in the Consumer Product Safety Improvement Act of 2008, this report provides information on what is known about (1) the health risks of exposure to formaldehyde, particularly from clothing, and (2) the levels of formaldehyde in clothing sold in the United States. GAO analyzed government reviews and the medical literature, as well as studies on levels of formaldehyde in clothing, and had a sample of 180 textiles--primarily clothing--tested for formaldehyde by an accredited laboratory. While illustrative of formaldehyde levels that may be found in clothing, the test results from GAO's sample cannot be projected to all clothing sold in the United States."
Date: August 13, 2010
Creator: United States. Government Accountability Office.
Partner: UNT Libraries Government Documents Department

Formaldehyde Absorption toward W51

Description: We have measured formaldehyde (H{sub 2}CO) absorption toward the HII region complex W51A (G49.5-0.4) in the 6 cm and 2 cm wavelength rotational transitions with angular resolution of approximately 4 inch. The continuum HII region shows a large, previously undetected shell structure 5.5 pc along the major axis. We observe no H{sub 2}CO emission in regions of low continuum intensity. The absorption, converted to optical depth, shows a higher degree of clumping than previous maps at lower resolution. The good S/N of the maps allows accurate estimation of the complicated line profiles, showing some of the absorbing clouds to be quite patchy. We list the properties of the opacity spectra for a number of positions both in the clumps and in the more diffuse regions of the absorbing clouds, and derive column densities for the 1{sub 11} and 2{sub 12} rotational levels of ortho-formaldehyde.
Date: April 1, 1988
Creator: Kogut, A.; Smoot, G.F.; Bennett, C.L. & Petuchowski, S.J.
Partner: UNT Libraries Government Documents Department