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Sample records for mems-based formaldehyde gas

  1. Microfabricated Formaldehyde Gas Sensors

    Directory of Open Access Journals (Sweden)

    Karen C. Cheung

    2009-11-01

    Full Text Available Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation.

  2. Miniaturized MEMS-Based Gas Chromatograph for High Inertial Loads Associated with Planetary Missions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a rugged, miniaturized, low power MEMS-based gas chromatograph (GC) capable of handling the high inertial loads...

  3. Research and Development of Non-Spectroscopic MEMS-Based Sensor Arrays for Targeted Gas Detection

    Energy Technology Data Exchange (ETDEWEB)

    Loui, A; McCall, S K

    2011-10-24

    The ability to monitor the integrity of gas volumes is of interest to the stockpile surveillance community. Specifically, the leak detection of noble gases, at relevant concentration ranges and distinguished from other chemical species that may be simultaneously present, is particularly challenging. Aside from the laboratory-based method of gas chromatography-mass spectrometry (GC-MS), where samples may be collected by solid-phase microextraction (SPME) or cryofocusing, the other major approaches for gas-phase detection employ lasers typically operating in the mid-infrared wavelength region. While mass spectrometry can readily detect noble gases - the helium leak detector is an obvious example - laser-based methods such as infrared (IR) or Raman spectroscopy are completely insensitive to them as their monatomic nature precludes a non-zero dipole moment or changes in polarizability upon excitation. Therefore, noble gases can only be detected by one of two methods: (1) atomic emission spectroscopies which require the generation of plasmas through laser-induced breakdown, electrical arcing, or similar means; (2) non-spectroscopic methods which measure one or more physical properties (e.g., mass, thermal conductivity, density). In this report, we present our progress during Fiscal Year 2011 (FY11) in the research and development of a non-spectroscopic method for noble gas detection. During Fiscal Year 2010 (FY10), we demonstrated via proof-of-concept experiments that the combination of thermal conductivity detection (TCD) and coating-free damped resonance detection (CFDRD) using micro-electromechanical systems (MEMS) could provide selective sensing of these inert species. Since the MEMS-based TCD technology was directly adapted from a brassboard prototype commissioned by a previous chemical sensing project, FY11 efforts focused on advancing the state of the newer CFDRD method. This work, guided by observations previously reported in the open literature, has not only

  4. Trace gas sensing using quantum cascade lasers and a fiber-coupled optoacoustic sensor: Application to formaldehyde

    International Nuclear Information System (INIS)

    Elia, A; Lugara, P M; Scamarcio, G; Spagnolo, V; Di Franco, C

    2010-01-01

    We will report here on the design and realization of an optoacoustic sensor for the detection of formaldehyde. The sensor consists of a commercial QCL and a resonant PA cell. Two different cell configurations have been investigated: a 'standard' H cell and an innovative T-cell with an optical fiber directly inserted into. Two different type of sound detector have been employed: electret microphones and optical MEMS-based microphone. As possible applications, we will describe the results obtained in the detection of formaldehyde (CH 2 O), a gas of great interest for industrial processes and environmental monitoring.

  5. Formaldehyde

    Science.gov (United States)

    Information on formaldehyde and the regulation of formaldehyde emissions from composite wood products under the Formaldehyde Standards for Composite Wood Products Act in the Toxic Substances Control Act (TSCA).

  6. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    Science.gov (United States)

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  7. 75 FR 37792 - Formaldehyde Gas; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Science.gov (United States)

    2010-06-30

    ... AGENCY Formaldehyde Gas; Receipt of Application for Emergency Exemption, Solicitation of Public Comment... (OSWER) to use formaldehyde gas (CAS No. 82115-62-6) to decontaminate non-food contact surfaces to... Administrator to issue a quarantine exemption for the use of formaldehyde gas on non-food contact surfaces to...

  8. MEMS-Based Gas Sensor Using PdO-Decorated TiO2 Thin Film for Highly Sensitive and Selective H2 Detection with Low Power Consumption

    Science.gov (United States)

    Kwak, Seungmin; Shim, Young-Seok; Yoo, Yong Kyoung; Lee, Jin-Hyung; Kim, Inho; Kim, Jinseok; Lee, Kyu Hyoung; Lee, Jeong Hoon

    2018-03-01

    We report a micromachined H2 sensor that is composed of a Pt micro-heater, low-stress insulating layer (SiO2/SiNx/SiO2), Pt-interdigitated electrodes, and gas sensing materials. Three types of Pt micro-heater are designed as function of electrode width, and their thermal properties are systematically analyzed by finite element modeling FEM with infrared camera. The power consumptions when the surface temperature reached 150, 200, 250, and 300 °C are calculated to approximately 33, 48, 67 and 85 mW, respectively. The response of the PdO nanoparticles-decorated TiO2 thin films to H2 is much higher than those of other gases such as CH4 and CO at 200 °C (48 mW). Further, the response time is reduced to approximately 3 s. The enhancement of gas sensing properties is related to well-designed micro-heater and catalytic effects of PdO nanoparticles such as electronic and chemical sensitization. These results suggest that the PdO nanoparticles-decorated TiO2 thin film, namely MEMS-based H2 sensors are very promising for use in IoT application to improve the quality of human's life.

  9. MEMS based highly sensitive dual FET gas sensor using graphene decorated Pd-Ag alloy nanoparticles for H2 detection.

    Science.gov (United States)

    Sharma, Bharat; Kim, Jung-Sik

    2018-04-12

    A low power, dual-gate field-effect transistor (FET) hydrogen gas sensor with graphene decorated Pd-Ag for hydrogen sensing applications was developed. The FET hydrogen sensor was integrated with a graphene-Pd-Ag-gate FET (GPA-FET) as hydrogen sensor coupled with Pt-gate FET as a reference sensor on a single sensor platform. The sensing gate electrode was modified with graphene by an e-spray technique followed by Pd-Ag DC/MF sputtering. Morphological and structural properties were studied by FESEM and Raman spectroscopy. FEM simulations were performed to confirm the uniform temperature control at the sensing gate electrode. The GPA-FET showed a high sensing response to hydrogen gas at the temperature of 25~254.5 °C. The as-proposed FET H 2 sensor showed the fast response time and recovery time of 16 s, 14 s, respectively at the operating temperature of 245 °C. The variation in drain current was positively related with increased working temperature and hydrogen concentration. The proposed dual-gate FET gas sensor in this study has potential applications in various fields, such as electronic noses and automobiles, owing to its low-power consumption, easy integration, good thermal stability and enhanced hydrogen sensing properties.

  10. 40 CFR 86.120-94 - Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... calibration; particulate, methanol and formaldehyde measurement. 86.120-94 Section 86.120-94 Protection of... Procedures § 86.120-94 Gas meter or flow instrumentation calibration; particulate, methanol and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters...

  11. Mononuclear metavanadate catalyses gas phase oxidation of methanol to formaldehyde employing dioxygen as the terminal oxidant.

    Science.gov (United States)

    Waters, Tom; Khairallah, George N; Wimala, Samantha A S Y; Ang, Yien C; O'Hair, Richard A J; Wedd, Anthony G

    2006-11-21

    Multistage mass spectrometry experiments reveal a sequence of gas phase reactions for the oxidation of methanol to formaldehyde with a mononuclear oxo vanadate anion as the catalyst and dioxygen as the terminal oxidant.

  12. 40 CFR 86.1320-90 - Gas meter or flow instrumentation calibration; particulate, methanol, and formaldehyde measurement.

    Science.gov (United States)

    2010-07-01

    ... calibration; particulate, methanol, and formaldehyde measurement. 86.1320-90 Section 86.1320-90 Protection of... instrumentation calibration; particulate, methanol, and formaldehyde measurement. (a) Sampling for particulate, methanol and formaldehyde emissions requires the use of gas meters or flow instrumentation to determine...

  13. Solid polymer MEMS-based fuel cells

    Science.gov (United States)

    Jankowski, Alan F [Livermore, CA; Morse, Jeffrey D [Pleasant Hill, CA

    2008-04-22

    A micro-electro-mechanical systems (MEMS) based thin-film fuel cells for electrical power applications. The MEMS-based fuel cell may be of a solid oxide type (SOFC), a solid polymer type (SPFC), or a proton exchange membrane type (PEMFC), and each fuel cell basically consists of an anode and a cathode separated by an electrolyte layer. The electrolyte layer can consist of either a solid oxide or solid polymer material, or proton exchange membrane electrolyte materials may be used. Additionally catalyst layers can also separate the electrodes (cathode and anode) from the electrolyte. Gas manifolds are utilized to transport the fuel and oxidant to each cell and provide a path for exhaust gases. The electrical current generated from each cell is drawn away with an interconnect and support structure integrated with the gas manifold. The fuel cells utilize integrated resistive heaters for efficient heating of the materials. By combining MEMS technology with thin-film deposition technology, thin-film fuel cells having microflow channels and full-integrated circuitry can be produced that will lower the operating temperature an will yield an order of magnitude greater power density than the currently known fuel cells.

  14. RELATION BETWEEN MECHANICAL PROPERTIES AND PYROLYSIS TEMPERATURE OF PHENOL FORMALDEHYDE RESIN FOR GAS SEPARATION MEMBRANES

    Directory of Open Access Journals (Sweden)

    MONIKA ŠUPOVÁ

    2012-03-01

    Full Text Available The aim of this paper has been to characterize the relation between the pyrolysis temperature of phenol-formaldehyde resin, the development of a porous structure, and the mechanical properties for the application of semipermeable membranes for gas separation. No previous study has dealt with this problem in its entirety. Phenol-formaldehyde resin showed an increasing trend toward micropore porosity in the temperature range from 500 till 1000°C, together with closure of mesopores and macropores. Samples cured and pyrolyzed at 1000°C pronounced hysteresis of desorption branch. The ultimate bending strength was measured using a four-point arrangement that is more suitable for measuring of brittle materials. The chevron notch technique was used for determination the fracture toughness. The results for mechanical properties indicated that phenol-formaldehyde resin pyrolyzates behaved similarly to ceramic materials. The data obtained for the material can be used for calculating the technical design of gas separation membranes.

  15. Formaldehyde gas sensor based on nanostructured nickel oxide and the microstructure effects on its response

    Science.gov (United States)

    Lahem, D.; Lontio, F. R.; Delcorte, A.; Bilteryst, L.; Debliquy, M.

    2016-03-01

    NiO nanostructures can be used as a promising material for semiconductor gas sensor to detect formaldehyde at low concentrations (nanostructures on gas sensing properties is studied and discussed. NiO nanostructures have been synthesized by thermal decomposition of precursors obtained by two different chemical precipitation methods and a sol-gel technique. Thick films of the synthesized NiO nanostructures were deposited by spray coating on alumina substrates fitted with gold interdigitated electrodes and a platinum heater. The gas sensing properties of those NiO films were studied for low concentrations of formaldehyde gas at different working temperatures. A clear difference in response characteristics was observed between the samples prepared by different synthesis routes.

  16. Gas-diffusion microextraction coupled with spectrophotometry for the determination of formaldehyde in cork agglomerates.

    Science.gov (United States)

    Brandão, Pedro F; Ramos, Rui M; Valente, Inês M; Almeida, Paulo J; Carro, Antonia M; Lorenzo, Rosa A; Rodrigues, José A

    2017-04-01

    In this work, a simple methodology was developed for the extraction and determination of free formaldehyde content in cork agglomerate samples. For the first time, gas-diffusion microextraction was used for the extraction of volatile formaldehyde directly from samples, with simultaneous derivatization with acetylacetone (Hantzsch reaction). The absorbance of the coloured solution was read in a spectrophotometer at 412 nm. Different extraction parameters were studied and optimized (extraction temperature, sample mass, volume of acceptor solution, extraction time and concentration of derivatization reagent) by means of an asymmetric screening. The developed methodology proved to be a reliable tool for the determination of formaldehyde in cork agglomerates with the following suitable method features: low LOD (0.14 mg kg -1 ) and LOQ (0.47 mg kg -1 ), r 2  = 0.9994, and intraday and interday precision of 3.5 and 4.9%, respectively. The developed methodology was applied to the determination of formaldehyde in different cork agglomerate samples, and contents between 1.9 and 9.4 mg kg -1 were found. Furthermore, formaldehyde was also determined by the standard method EN 717-3 for comparison purposes; no significant differences between the results of both methods were observed. Graphical abstract Representation of the GDME system and its main components.

  17. Removal of formaldehyde from gas streams via packed-bed dielectric barrier discharge plasmas

    International Nuclear Information System (INIS)

    Ding Huixian; Zhu Aimin; Yang Xuefeng; Li Cuihong; Xu Yong

    2005-01-01

    Formaldehyde is a major indoor air pollutant and can cause serious health disorders in residents. This work reports the removal of formaldehyde from gas streams via alumina-pellet-filled dielectric barrier discharge plasmas at atmospheric pressure and 70 deg. C. With a feed gas mixture of 140 ppm HCHO, 21.0% O 2 , 1.0% H 2 O in N 2 , ∼92% of formaldehyde can be effectively destructed at GHSV (gas flow volume per hour per discharge volume) of 16 500 h -1 and E in = 108 J l -1 . An increase in the specific surface area of the alumina pellets enhances the HCHO removal, and this indicates that the adsorbed HCHO species may have a lower C-H bond breakage energy. Based on an examination of the influence of gas composition on the removal efficiency, the primary destruction pathways, besides the reactions initiated by discharge-generated radicals, such as O, H, OH and HO 2 , may include the consecutive dissociations of HCHO molecules and HCO radicals through their collisions with vibrationally- and electronically-excited metastable N 2 species. The increase of O 2 content in the inlet gas stream is able to diminish the CO production and to promote the formation of CO 2 via O-atom or HO 2 -radical involved reactions

  18. Selective Detection of Formaldehyde Gas Using a Cd-Doped TiO2-SnO2 Sensor

    Directory of Open Access Journals (Sweden)

    Yuichi Ikuhara

    2009-11-01

    Full Text Available We report the microstructure and gas-sensing properties of a nonequilibrium TiO2-SnO2 solid solution prepared by the sol-gel method. In particular, we focus on the effect of Cd doping on the sensing behavior of the TiO2-SnO2 sensor. Of all volatile organic compound gases examined, the sensor with Cd doping exhibits exclusive selectivity as well as high sensitivity to formaldehyde, a main harmful indoor gas. The key gas-sensing quantities, maximum sensitivity, optimal working temperature, and response and recovery time, are found to meet the basic industrial needs. This makes the Cd-doped TiO2-SnO2 composite a promising sensor material for detecting the formaldehyde gas.

  19. 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.

  20. MEMS-BASED OSCILLATORS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Jamilah Karim

    2014-05-01

    Full Text Available ABSTRACT: This paper presents an overview of microelectromechanical (MEMS based oscillators. The accuracy and stability of the reference frequency will normally limit the performance of most wireless communication systems. MEMS technology is the technology of choice due to its compatibility to silicon, leading to integration with circuits and lowering power consumption. MEMS based oscillators also provide the potential of a fully integrated transceiver. The most commonly used topology for MEMS based oscillators are pierce oscillator circuit topology and TIA circuit topology. Both topologies result in very competitive output in terms of phase noise and power consumption.  They can be used for either higher or lower Rx. The major difference between both topologies is the number of transistors used. TIA circuit used more number of transistor compare to pierce circuit. Thus design complexity of the TIA is higher. Pierce circuit is simpler, provide straightforward biasing and easier to design. The highly integratable of MEMS-based oscillators have made them much needed in future multiband wireless system. So that future wireless systems are able to function globally without any problem. ABSTRAK: Kertas kerja ini membentangkan gambaran keseluruhan mikroelektromekanikal (MEMS berdasarkan pengayun.  Ketepatan dan kestabilan frekuensi rujukan sering membataskan perlaksanaan kebanyakan sistem komunikasi tanpa wayar. Teknologi MEMS merupakan teknologi pilihan memandangkan ia serasi dengan silikon; membolehkan integrasi dengan litar dan penggunaan tenaga yang rendah.  Pengayun berdasarkan MEMS juga  berpotensi sebagai integrasi penuh penghantar-terima. Topologi yang sering digunakan untuk pengayun berdasarkan MEMS adalah topologi litar pengayun pencantas dan topologi litar TIA.  Keputusan bagi kedua-dua topologi adalah amat kompetitif dari segi fasa bunyi dan penggunaan tenaga. Ia boleh digunakan untuk meninggikan atau merendahkan Rx. Perbezaan utama

  1. Gas-phase thermolysis reaction of formaldehyde diperoxide. Kinetic study and theoretical mechanisms

    International Nuclear Information System (INIS)

    Jorge, Nelly Lidia; Romero, Jorge Marcelo; Grand, André; Hernández-Laguna, Alfonso

    2012-01-01

    Highlights: ► Kinetic and mechanism of the gas-phase thermolysis of tetroxane were determined. ► Gas chromatography and computational potential energy surfaces were performed. ► A mechanism in steps looked like the most probable mechanism. ► A spin–orbit coupling appeared at the singlet and triple diradical open structures. ► A non-adiabatic crossing from the singlet to the triplet state occurred. - Abstract: Gas-phase thermolysis reaction of formaldehyde diperoxide (1,2,4,5-tetroxane) was performed in an injection chamber of a gas chromatograph at a range of 463–503 K. The average Arrhenius activation energy and pre-exponential factor were 29.3 ± 0.8 kcal/mol and 5.2 × 10 13 s −1 , respectively. Critical points and reaction paths of the ground singlet and first triplet potential energy surfaces (PES) were calculated, using DFT method at BHANDHLYP/6-311+G ∗∗ level of the theory. Also, G3 calculations were performed on the reactant and products. Reaction by the ground-singlet and first-triplet states turned out to be endothermic and exothermic, respectively. The mechanism in three steps seemed to be the most probable one. An electronically non-adiabatic process appeared, in which a crossing, at an open diradical structure, from the singlet to the triplet state PES occurred, due to a spin–orbit coupling, yielding an exothermic reaction. Theoretical kinetic constant coming from the non- adiabatic transition from the singlet to the triplet state agrees with the experimental values.

  2. Gas-phase thermolysis reaction of formaldehyde diperoxide. Kinetic study and theoretical mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Jorge, Nelly Lidia [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Av. Las Palmeras 4, 18100 Armilla, Granada (Spain); Area de Quimica Fisica Facultad de Ciencias Exactas y Naturales y Agrimensura, UNNE, Avda. Libertad 5460, 3400 Corrientes (Argentina); Romero, Jorge Marcelo [Area de Quimica Fisica Facultad de Ciencias Exactas y Naturales y Agrimensura, UNNE, Avda. Libertad 5460, 3400 Corrientes (Argentina); Grand, Andre [INAC, SCIB, Laboratoire ' Lesions des Acides Nucleiques' , UMR CEA-UJF E3, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble cedex 9 (France); Hernandez-Laguna, Alfonso, E-mail: ahlaguna@ugr.es [Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Av. Las Palmeras 4, 18100 Armilla, Granada (Spain)

    2012-01-17

    Highlights: Black-Right-Pointing-Pointer Kinetic and mechanism of the gas-phase thermolysis of tetroxane were determined. Black-Right-Pointing-Pointer Gas chromatography and computational potential energy surfaces were performed. Black-Right-Pointing-Pointer A mechanism in steps looked like the most probable mechanism. Black-Right-Pointing-Pointer A spin-orbit coupling appeared at the singlet and triple diradical open structures. Black-Right-Pointing-Pointer A non-adiabatic crossing from the singlet to the triplet state occurred. - Abstract: Gas-phase thermolysis reaction of formaldehyde diperoxide (1,2,4,5-tetroxane) was performed in an injection chamber of a gas chromatograph at a range of 463-503 K. The average Arrhenius activation energy and pre-exponential factor were 29.3 {+-} 0.8 kcal/mol and 5.2 Multiplication-Sign 10{sup 13} s{sup -1}, respectively. Critical points and reaction paths of the ground singlet and first triplet potential energy surfaces (PES) were calculated, using DFT method at BHANDHLYP/6-311+G{sup Asterisk-Operator Asterisk-Operator} level of the theory. Also, G3 calculations were performed on the reactant and products. Reaction by the ground-singlet and first-triplet states turned out to be endothermic and exothermic, respectively. The mechanism in three steps seemed to be the most probable one. An electronically non-adiabatic process appeared, in which a crossing, at an open diradical structure, from the singlet to the triplet state PES occurred, due to a spin-orbit coupling, yielding an exothermic reaction. Theoretical kinetic constant coming from the non- adiabatic transition from the singlet to the triplet state agrees with the experimental values.

  3. Rh(I)-catalyzed CO gas-free carbonylative cyclization reactions of alkynes with 2-bromophenylboronic acids using formaldehyde.

    Science.gov (United States)

    Morimoto, Tsumoru; Yamasaki, Kae; Hirano, Akihisa; Tsutsumi, Ken; Kagawa, Natsuko; Kakiuchi, Kiyomi; Harada, Yasuyuki; Fukumoto, Yoshiya; Chatani, Naoto; Nishioka, Takanori

    2009-04-16

    The rhodium(I)-catalyzed reaction of alkynes with 2-bromophenylboronic acids in the presence of paraformaldehyde resulted in a CO gas-free carbonylative cyclization, yielding indenone derivatives. [RhCl(BINAP)](2) and [RhCl(cod)](2) were responsible for the decarbonylation of formaldehyde and the subsequent carbonylation of alkynes with 2-haloboronic acids, respectively, leading to efficient whole carbonylation. Sterically bulky and electron-withdrawing groups on unsymmetrically substituted alkynes favored the alpha-position of indenones.

  4. Shutdown Policies for MEMS-Based Storage Devices -- Analytical Models

    NARCIS (Netherlands)

    Khatib, M.G.; Engelen, Johannes Bernardus Charles; Hartel, Pieter H.

    MEMS-based storage devices should be energy ecient for deployment in mobile systems. Since MEMS-based storage devices have a moving me- dia sled, they should be shut down during periods of inactivity. However, shutdown costs energy, limiting the applicability of aggressive shutdown decisions. The

  5. Gas Generation Testing of Spherical Resorcinol-Formaldehyde (sRF) Resin

    Energy Technology Data Exchange (ETDEWEB)

    Colburn, Heather A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bryan, Samuel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Camaioni, Donald M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mahoney, Lenna A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adami, Susan R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2018-01-19

    This report describes gas generation testing of the spherical resorcinol-formaldehyde (sRF) resin that was conducted to support the technology maturation of the LAWPS facility. The current safety basis for the LAWPS facility is based primarily on two studies that had limited or inconclusive data sets. The two studies indicated a 40% increase in hydrogen generation rate of water (as predicted by the Hu model) with sRF resin over water alone. However, the previous studies did not test the range of conditions (process fluids and temperatures) that are expected in the LAWPS facility. Additionally, the previous studies did not obtain replicate test results or comparable liquid-only control samples. All of the testing described in this report, conducted with water, 0.45M nitric acid, and waste simulants with and without sRF resin, returned hydrogen generation rates that are within the current safety basis for the facility of 1.4 times the Hu model output for water.

  6. Production of sugarcane bagasse-based activated carbon for formaldehyde gas removal from potted plants exposure chamber.

    Science.gov (United States)

    Mohamed, Elham F; El-Hashemy, Mohammed A; Abdel-Latif, Nasser M; Shetaya, Waleed H

    2015-12-01

    Agricultural wastes such as rice straw, sugar beet, and sugarcane bagasse have become a critical environmental issue due to growing agriculture demand. This study aimed to investigate the valorization possibility of sugarcane bagasse waste for activated carbon preparation. It also aimed to fully characterize the prepared activated carbon (BET surface area) via scanning electron microscope (SEM) and in terms of surface functional groups to give a basic understanding of its structure and to study the adsorption capacity of the sugarcane bagasse-based activated carbon using aqueous methylene blue (MB). The second main objective was to evaluate the performance of sugarcane bagasse-based activated carbon for indoor volatile organic compounds removal using the formaldehyde gas (HCHO) as reference model in two potted plants chambers. The first chamber was labeled the polluted chamber (containing formaldehyde gas without activated carbon) and the second was taken as the treated chamber (containing formaldehyde gas with activated carbon). The results indicated that the sugarcane bagasse-based activated carbon has a moderate BET surface area (557 m2/g) with total mesoporous volume and microporous volume of 0.310 and 0.273 cm3/g, respectively. The prepared activated carbon had remarkable adsorption capacity for MB. Formaldehyde removal rate was then found to be more than 67% in the treated chamber with the sugarcane bagasse-based activated carbon. The plants' responses for this application as dry weight, chlorophyll contents, and protein concentration were also investigated. Preparation of activated carbon from sugarcane bagasse (SCBAC) is a promising approach to produce cheap and efficient adsorbent for gas pollutants removal. It may be also a solution for the agricultural wastes problems in big cities, particularly in Egypt. MB adsorption tests suggest that the SCBAC have high adsorption capacity. Formaldehyde gas removal in the plant chambers indicates that the SCBAC have

  7. The ALMA-PILS Survey: Formaldehyde deuteration in warm gas on small scales toward IRAS 16293-2422 B

    Science.gov (United States)

    Persson, M. V.; Jørgensen, J. K.; Müller, H. S. P.; Coutens, A.; van Dishoeck, E. F.; Taquet, V.; Calcutt, H.; van der Wiel, M. H. D.; Bourke, T. L.; Wampfler, S. F.

    2018-02-01

    Context. The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance of chemistry at low temperatures, relevant in pre- and protostellar cores. Formaldehyde is an important species in the formation of methanol and more complex molecules. Aims: Here, we aim to present the first study of formaldehyde deuteration on small scales around the prototypical low-mass protostar IRAS 16293-2422 using high spatial and spectral resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations. We determine the excitation temperature, abundances and fractionation level of several formaldehyde isotopologues, including its deuterated forms. Methods: Excitation temperature and column densities of formaldehyde in the gas close to one of the components of the binary were constrained through modeling of optically thin lines assuming local thermodynamical equilibrium. The abundance ratios were compared to results from previous single dish observations, astrochemical models and local ISM values. Results: Numerous isotopologues of formaldehyde are detected, among them H2C17O, and D213CO for the first time in the ISM. The large range of upper energy levels covered by the HDCO lines help constrain the excitation temperature to 106 ± 13 K. Using the derived column densities, formaldehyde shows a deuterium fractionation of HDCO/H2CO = 6.5 ± 1%, D2CO/HDCO = 12.8-4.1+3.3%, and D2CO/H2CO = 0.6(4) ± 0.1%. The isotopic ratios derived are 16O/18O = 805-79+43, 18O/17O = 3.2-0.3+0.2, and 12C/13C = 56-11+8. Conclusions: The HDCO/H2CO ratio is lower than that found in previous studies, highlighting the uncertainties involved in interpreting single dish observations of the inner warm regions. The D2CO/HDCO ratio is only slightly larger than the HDCO/H2CO ratio. This is consistent with formaldehyde forming in the ice as soon as CO has frozen onto the grains, with most of the deuteration happening toward the end of the prestellar core

  8. A Hollow-Waveguide Gas Correlation Radiometer for Ultra-Precise Column Measurements of Formaldehyde on Mars

    Science.gov (United States)

    Wilson, Emily L.; Neveu, Marc; Riris, Haris; Georgieva, Elena M.; Heaps, William S.

    2011-01-01

    We present preliminary results in the development of a miniaturized gas correlation radiometer that implements a hollow-core optical fiber (hollow waveguide) gas correlation cell. The substantial reduction in mass and volume of the gas correlation cell makes this technology appropriate for an orbital mission -- capable of pinpointing sources of trace gases in the Martian atmosphere. Here we demonstrate a formaldehyde (H2CO) sensor and report a detection limit equivalent to approximately 30 ppb in the Martian atmosphere. The relative simplicity of the technique allows it to be expanded to measure a range of atmospheric trace gases of interest on Mars such as methane (CH4), water vapour (H2O), deuterated water vapour (HDO), and methanol (CH3OH). Performance of a formaldehyde instrument in a Mars orbit has been simulated assuming a 3 meter long, 1000 micron inner diameter hollow-core fiber gas correlation cell, a 92.8 degree sun-synchronous orbit from 400 km with a horizontal sampling scale of 10 km x 10 km. Initial results indicate that for one second of averaging, a detection limit of 1 ppb is possible.

  9. MEMS-based transmission lines for microwave applications

    Science.gov (United States)

    Wu, Qun; Fu, Jiahui; Gu, Xuemai; Shi, Huajuan; Lee, Jongchul

    2003-04-01

    This paper mainly presents a briefly review for recent progress in MEMS-based transmission lines for use in microwave and millimeterwave range. MEMS-based transmission lines including different transmission line structure such as membrane-supported microstrip line microstrip line, coplanar microshield transmission line, LIGA micromachined planar transmission line, micromachined waveguides and coplanar waveguide are discussed. MEMS-based transmission lines are characterized by low propagation loss, wide operation frequency band, low dispersion and high quality factor, in addition, the fabrication is compatible with traditional processing of integrated circuits (IC"s). The emergence of MEMS-based transmission lines provided a solution for miniaturizing microwave system and monolithic microwave integrated circuits.

  10. MEMS-based thermoelectric infrared sensors: A review

    Science.gov (United States)

    Xu, Dehui; Wang, Yuelin; Xiong, Bin; Li, Tie

    2017-12-01

    In the past decade, micro-electromechanical systems (MEMS)-based thermoelectric infrared (IR) sensors have received considerable attention because of the advances in micromachining technology. This paper presents a review of MEMS-based thermoelectric IR sensors. The first part describes the physics of the device and discusses the figures of merit. The second part discusses the sensing materials, thermal isolation microstructures, absorber designs, and packaging methods for these sensors and provides examples. Moreover, the status of sensor implementation technology is examined from a historical perspective by presenting findings from the early years to the most recent findings.

  11. Power Management of MEMS-Based Storage Devices for Mobile Systems

    NARCIS (Netherlands)

    Khatib, M.G.; Hartel, Pieter H.

    2008-01-01

    Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. MEMS-based storage devices should also be energy efficient for deployment in mobile systems. The problem is that MEMS-based storage devices are mechanical,

  12. Workload-Based Configuration of MEMS-Based Storage Devices for Mobile Systems

    NARCIS (Netherlands)

    Khatib, M.G.; Miller, E.L.; Hartel, Pieter H.

    2008-01-01

    Because of its small form factor, high capacity, and expected low cost, MEMS-based storage is a suitable storage technology for mobile systems. However, flash memory may outperform MEMS-based storage in terms of performance, and energy-efficiency. The problem is that MEMS-based storage devices have

  13. Cell proliferation in rat nasal respiratory epithelium following three months exposure to formaldehyde gas

    International Nuclear Information System (INIS)

    Monticello, T.M.; Morgan, K.T.

    1990-01-01

    Formaldehyde (HCHO), a ubiquitous chemical and rat nasal carcinogen, enhances cell proliferation in rat, monkey, and xenotransplanted human respiratory epithelium following short-term exposure. The present studies were designed to evaluate cell proliferation in relation to tumor induction in rat nasal respiratory epithelium following subchronic HCHO exposure. Male F-344 rats were whole-body exposed to either 0, 0.7, 2, 6, 10, or 15 ppm HCHO, for wither 4 d (6hr/d), 6 wks (5d/wk) or 3 months. Animals were labeled with tritiated thymidine prior to euthanasia. Nasal sections were processed for autoradiography and cell proliferation data was expressed as unit length labeling indices (ULLI). HCHO-induced lesions and increases in cell proliferation occurred in specific regions of the nose, primarily the wall of the lateral meatus and nasal septum of the anterior nasal cavity. Following 4 d exposure, significant elevations in cell proliferation were observed only in the 6, 10 and 15 ppm groups (16-, 18-, and 20-fold increase over control, respectively). Increases in ULLI were also present in the 6, 10 and 15 ppm groups after 6 wks of exposure (12-, 35-, and 40-fold increase over control). However, after 3 months exposure, elevations in ULLI were present only in the 10 and 15 ppm groups (9- and 14-fold increase over controls). These results demonstrate that (1) low levels of HCHO (0.7 and 2 ppm) do not increase cell proliferation in rat nasal respiratory epithelium; (2) 6 ppm HCHO induces transient increases in cell proliferation; and (3) clearly carcinogenic concentrations of HCHO (10 and 15 ppm) cause sustained elevations in cell proliferation which may play an important role in HCHO-induced carcinogenesis

  14. MEMS-based Circuits and Systems for Wireless Communication

    CERN Document Server

    Kaiser, Andreas

    2013-01-01

    MEMS-based Circuits and Systems for Wireless Communication provides comprehensive coverage of RF-MEMS technology from device to system level. This edited volume places emphasis on how system performance for radio frequency applications can be leveraged by Micro-Electro-Mechanical Systems (MEMS). Coverage also extends to innovative MEMS-aware radio architectures that push the potential of MEMS technology further ahead.  This work presents a broad overview of the technology from MEMS devices (mainly BAW and Si MEMS resonators) to basic circuits, such as oscillators and filters, and finally complete systems such as ultra-low-power MEMS-based radios. Contributions from leading experts around the world are organized in three parts. Part I introduces RF-MEMS technology, devices and modeling and includes a prospective outlook on ongoing developments towards Nano-Electro-Mechanical Systems (NEMS) and phononic crystals. Device properties and models are presented in a circuit oriented perspective. Part II focusses on ...

  15. Staging of RF-accelerating Units in a MEMS-based Ion Accelerator

    Science.gov (United States)

    Persaud, A.; Seidl, P. A.; Ji, Q.; Feinberg, E.; Waldron, W. L.; Schenkel, T.; Ardanuc, S.; Vinayakumar, K. B.; Lal, A.

    Multiple Electrostatic Quadrupole Array Linear Accelerators (MEQALACs) provide an opportunity to realize compact radio- frequency (RF) accelerator structures that can deliver very high beam currents. MEQALACs have been previously realized with acceleration gap distances and beam aperture sizes of the order of centimeters. Through advances in Micro-Electro-Mechanical Systems (MEMS) fabrication, MEQALACs can now be scaled down to the sub-millimeter regime and batch processed on wafer substrates. In this paper we show first results from using three RF stages in a compact MEMS-based ion accelerator. The results presented show proof-of-concept with accelerator structures formed from printed circuit boards using a 3 × 3 beamlet arrangement and noble gas ions at 10 keV. We present a simple model to describe the measured results. We also discuss some of the scaling behaviour of a compact MEQALAC. The MEMS-based approach enables a low-cost, highly versatile accelerator covering a wide range of currents (10 μA to 100 mA) and beam energies (100 keV to several MeV). Applications include ion-beam analysis, mass spectrometry, materials processing, and at very high beam powers, plasma heating.

  16. MEMS-based thick film PZT vibrational energy harvester

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Thyssen, Anders

    2011-01-01

    We present a MEMS-based unimorph silicon/PZT thick film vibrational energy harvester with an integrated proof mass. We have developed a process that allows fabrication of high performance silicon based energy harvesters with a yield higher than 90%. The process comprises a KOH etch using...... a mechanical front side protection of an SOI wafer with screen printed PZT thick film. The fabricated harvester device produces 14.0 μW with an optimal resistive load of 100 kΩ from 1g (g=9.81 m s-2) input acceleration at its resonant frequency of 235 Hz....

  17. Update on MEMS-based scanned beam imager

    Science.gov (United States)

    James, Richard; Gibson, Greg; Metting, Frank; Davis, Wyatt; Drabe, Christian

    2007-01-01

    In 2004, Microvision presented "Scanned Beam Medical Imager" as an introduction to our MEMS-based, full color scanned beam imaging system. This presentation will provide an update of the technological advancements since this initial work from 2004. This recent work includes the development of functional prototypes that are much smaller than previous prototypes using a design architecture that is easily scalable. Performance has been significantly improved by increasing the optical field of views and video refresh rate. Real-time image processing capabilities have been developed to enhance the image quality and functionality over a wide range of operating conditions. Actual images of various objects will be presented.

  18. Compact multichannel MEMS based spectrometer for FBG sensing

    Science.gov (United States)

    Ganziy, D.; Rose, B.; Bang, O.

    2017-04-01

    We propose a novel type of compact multichannel MEMS based spectrometer, where we replace the linear detector with a Digital Micromirror Device (DMD). The DMD is typically cheaper and has better pixel sampling than an InGaAs detector used in the 1550 nm range, which leads to cost reduction and better performance. Moreover, the DMD is a 2D array, which means that multichannel systems can be implemented without any additional optical components in the spectrometer. This makes the proposed interrogator highly cost-effective. The digital nature of the DMD also provides opportunities for advanced programmable spectroscopy.

  19. Compact multichannel MEMS based spectrometer for FBG sensing

    DEFF Research Database (Denmark)

    Ganziy, Denis; Rose, Bjarke; Bang, Ole

    2017-01-01

    We propose a novel type of compact multichannel MEMS based spectrometer, where we replace the linear detector with a Digital Micromirror Device (DMD). The DMD is typically cheaper and has better pixel sampling than an InGaAs detector used in the 1550 nm range, which leads to cost reduction...... and better performance. Moreover, the DMD is a 2D array, which means that multichannel systems can be implemented without any additional optical components in the spectrometer. This makes the proposed interrogator highly cost-effective. The digital nature of the DMD also provides opportunities for advanced...

  20. MEMS-Based Fuel Reformer with Suspended Membrane Structure

    Science.gov (United States)

    Chang, Kuei-Sung; Tanaka, Shuji; Esashi, Masayoshi

    We report a MEMS-based fuel reformer for supplying hydrogen to micro-fuel cells for portable applications. A combustor and a reforming chamber are fabricated at either side of a suspended membrane structure. This design is used to improve the overall thermal efficiency, which is a critical issue to realize a micro-fuel reformer. The suspended membrane structure design provided good thermal isolation. The micro-heaters consumed 0.97W to maintain the reaction zone of the MEMS-based fuel reformer at 200°C, but further power saving is necessary by improving design and fabrication. The conversion rate of methanol to hydrogen was about 19% at 180°C by using evaporated copper as a reforming catalyst. The catalytic combustion of hydrogen started without any assistance of micro-heaters. By feeding the fuel mixture of an equivalence ratio of 0.35, the temperature of the suspended membrane structure was maintained stable at 100°C with a combustion efficiency of 30%. In future works, we will test a micro-fuel reformer by using a micro-combustor to supply heat.

  1. Optimizing MEMS-Based Storage Devices for Mobile Battery-Powered Systems

    NARCIS (Netherlands)

    Khatib, M.G.; Hartel, Pieter H.

    An emerging storage technology, called MEMS-based storage, promises nonvolatile storage devices with ultrahigh density, high rigidity, a small form factor, and low cost. For these reasons, MEMS-based storage devices are suitable for battery-powered mobile systems such as PDAs. For deployment in such

  2. Microwave Cure of Phenol-Formaldehyde Adhesive

    OpenAIRE

    高谷, 政広; 田平, 英敏; 岡本, 忠

    2006-01-01

    [Synopsis] Phenol-formaldehyde resin has been used as a versatile material for adhesives and coatings of a wide range of adherends because of its excellent performance in water- resistance, strength against abrasion, and so on. However, it has a drawback of slow rate of cure and relevant emission of formaldehyde gas after bonding. We studied the curing performance under irradiation of microwave for the purpose of looking for a way of accelerating the cure rate of phenol formaldehyde resin. Th...

  3. Large area MEMS based ultrasound device for cancer detection

    International Nuclear Information System (INIS)

    Wodnicki, Robert; Thomenius, Kai; Ming Hooi, Fong; Sinha, Sumedha P.; Carson, Paul L.; Lin Dersong; Zhuang Xuefeng; Khuri-Yakub, Pierre; Woychik, Charles

    2011-01-01

    We present image results obtained using a prototype ultrasound array that demonstrates the fundamental architecture for a large area MEMS based ultrasound device for detection of breast cancer. The prototype array consists of a tiling of capacitive Micromachined Ultrasound Transducers (cMUTs) that have been flip-chip attached to a rigid organic substrate. The pitch on the cMUT elements is 185 μm and the operating frequency is nominally 9 MHz. The spatial resolution of the new probe is comparable to those of production PZT probes; however the sensitivity is reduced by conditions that should be correctable. Simulated opposed-view image registration and Speed of Sound volume reconstruction results for ultrasound in the mammographic geometry are also presented.

  4. Large area MEMS based ultrasound device for cancer detection

    Science.gov (United States)

    Wodnicki, Robert; Thomenius, Kai; Ming Hooi, Fong; Sinha, Sumedha P.; Carson, Paul L.; Lin, Der-Song; Zhuang, Xuefeng; Khuri-Yakub, Pierre; Woychik, Charles

    2011-08-01

    We present image results obtained using a prototype ultrasound array that demonstrates the fundamental architecture for a large area MEMS based ultrasound device for detection of breast cancer. The prototype array consists of a tiling of capacitive Micromachined Ultrasound Transducers (cMUTs) that have been flip-chip attached to a rigid organic substrate. The pitch on the cMUT elements is 185 μm and the operating frequency is nominally 9 MHz. The spatial resolution of the new probe is comparable to those of production PZT probes; however the sensitivity is reduced by conditions that should be correctable. Simulated opposed-view image registration and Speed of Sound volume reconstruction results for ultrasound in the mammographic geometry are also presented.

  5. Large area MEMS based ultrasound device for cancer detection

    Energy Technology Data Exchange (ETDEWEB)

    Wodnicki, Robert, E-mail: wodnicki@research.ge.com [GE Global Research, 1 Research Circle, Niskayuna, NY 12309 (United States); Thomenius, Kai [GE Global Research, 1 Research Circle, Niskayuna, NY 12309 (United States); Ming Hooi, Fong; Sinha, Sumedha P.; Carson, Paul L. [Radiology and Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Lin Dersong; Zhuang Xuefeng; Khuri-Yakub, Pierre [Department of Electrical Engineering, Stanford University, Stanford, CA 94309 (United States); Woychik, Charles [GE Global Research, 1 Research Circle, Niskayuna, NY 12309 (United States)

    2011-08-21

    We present image results obtained using a prototype ultrasound array that demonstrates the fundamental architecture for a large area MEMS based ultrasound device for detection of breast cancer. The prototype array consists of a tiling of capacitive Micromachined Ultrasound Transducers (cMUTs) that have been flip-chip attached to a rigid organic substrate. The pitch on the cMUT elements is 185 {mu}m and the operating frequency is nominally 9 MHz. The spatial resolution of the new probe is comparable to those of production PZT probes; however the sensitivity is reduced by conditions that should be correctable. Simulated opposed-view image registration and Speed of Sound volume reconstruction results for ultrasound in the mammographic geometry are also presented.

  6. Formaldehyde vapor produced from hexamethylenetetramine and pesticide: Simultaneous monitoring of formaldehyde and ozone in chamber experiments by flow-based hybrid micro-gas analyzer.

    Science.gov (United States)

    Yanaga, Akira; Hozumi, Naruto; Ohira, Shin-Ichi; Hasegawa, Asako; Toda, Kei

    2016-02-01

    Simultaneous analysis of HCHO and O3 was performed by the developed flow analysis system to prove that HCHO vapor is produced from solid pesticide in the presence of O3. HCHO is produced in many ways, including as primary emissions from fuel combustion and in secondary production from anthropogenic and biogenic volatile organic compounds by photochemical reactions. In this work, HCHO production from pesticides was investigated for the first time. Commonly pesticide contains surfactant such as hexamethylenetetramine (HMT), which is a heterocyclic compound formed from six molecules of HCHO and four molecules of NH3. HMT can react with gaseous oxidants such as ozone (O3) to produce HCHO. In the present study, a flow analysis system was developed for simultaneous analysis of HCHO and O3, and this system was used to determine if solid pesticides produced HCHO vapor in the presence of O3. HMT or the pesticide jimandaisen, which contains mancozeb as the active ingradient and HMT as a stabilizer was placed at the bottom of a 20-L stainless steel chamber. Air in the chamber was monitored using the developed flow system. Analyte gases were collected into an absorbing solution by a honeycomb-patterned microchannel scrubber that was previously developed for a micro gas analysis system (μGAS). Subsequently, indigotrisulfonate, a blue dye, was added to the absorbing solution to detect O3, which discolored the solution. HCHO was detected after mixing with the Hantzsch reaction reagent. Both gases could be detected at concentrations ranging from parts per billion by volume (ppbv) to 1000 ppbv with good linearity. Both HMT and jimandaisen emitted large amount of HCHO in the presence of O3. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Design, modeling and simulation of MEMS-based silicon Microneedles

    Science.gov (United States)

    Amin, F.; Ahmed, S.

    2013-06-01

    The advancement in semiconductor process engineering and nano-scale fabrication technology has made it convenient to transport specific biological fluid into or out of human skin with minimum discomfort. Fluid transdermal delivery systems such as Microneedle arrays are one such emerging and exciting Micro-Electro Mechanical System (MEMS) application which could lead to a total painless fluid delivery into skin with controllability and desirable yield. In this study, we aimed to revisit the problem with modeling, design and simulations carried out for MEMS based silicon hollow out of plane microneedle arrays for biomedical applications particularly for transdermal drug delivery. An approximate 200 μm length of microneedle with 40 μm diameter of lumen has been successfully shown formed by isotropic and anisotropic etching techniques using MEMS Pro design tool. These microneedles are arranged in size of 2 × 4 matrix array with center to center spacing of 750 μm. Furthermore, comparisons for fluid flow characteristics through these microneedle channels have been modeled with and without the contribution of the gravitational forces using mathematical models derived from Bernoulli Equation. Physical Process simulations have also been performed on TCAD SILVACO to optimize the design of these microneedles aligned with the standard Si-Fabrication lines.

  8. Design, modeling and simulation of MEMS-based silicon Microneedles

    International Nuclear Information System (INIS)

    Amin, F; Ahmed, S

    2013-01-01

    The advancement in semiconductor process engineering and nano-scale fabrication technology has made it convenient to transport specific biological fluid into or out of human skin with minimum discomfort. Fluid transdermal delivery systems such as Microneedle arrays are one such emerging and exciting Micro-Electro Mechanical System (MEMS) application which could lead to a total painless fluid delivery into skin with controllability and desirable yield. In this study, we aimed to revisit the problem with modeling, design and simulations carried out for MEMS based silicon hollow out of plane microneedle arrays for biomedical applications particularly for transdermal drug delivery. An approximate 200 μm length of microneedle with 40 μm diameter of lumen has been successfully shown formed by isotropic and anisotropic etching techniques using MEMS Pro design tool. These microneedles are arranged in size of 2 × 4 matrix array with center to center spacing of 750 μm. Furthermore, comparisons for fluid flow characteristics through these microneedle channels have been modeled with and without the contribution of the gravitational forces using mathematical models derived from Bernoulli Equation. Physical Process simulations have also been performed on TCAD SILVACO to optimize the design of these microneedles aligned with the standard Si-Fabrication lines.

  9. Carbon microelectromechanical systems (C-MEMS) based microsupercapacitors

    KAUST Repository

    Agrawal, Richa

    2015-05-18

    The rapid development in miniaturized electronic devices has led to an ever increasing demand for high-performance rechargeable micropower scources. Microsupercapacitors in particular have gained much attention in recent years owing to their ability to provide high pulse power while maintaining long cycle lives. Carbon microelectromechanical systems (C-MEMS) is a powerful approach to fabricate high aspect ratio carbon microelectrode arrays, which has been proved to hold great promise as a platform for energy storage. C-MEMS is a versatile technique to create carbon structures by pyrolyzing a patterned photoresist. Furthermore, different active materials can be loaded onto these microelectrode platforms for further enhancement of the electrochemical performance of the C-MEMS platform. In this article, different techniques and methods in order to enhance C-MEMS based various electrochemical capacitor systems have been discussed, including electrochemical activation of C-MEMS structures for miniaturized supercapacitor applications, integration of carbon nanostructures like carbon nanotubes onto C-MEMS structures and also integration of pseudocapacitive materials such as polypyrrole onto C-MEMS structures. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  10. Fabrication and performance analysis of MEMS-based Variable Emissivity Radiator for Space Applications

    International Nuclear Information System (INIS)

    Lee, Changwook; Oh, Hyung-Ung; Kim, Taegyu

    2014-01-01

    All Louver was typically representative as the thermal control device. The louver was not suitable to be applied to small satellite, because it has the disadvantage of increase in weight and volume. So MEMS-based variable radiator was developed to support the disadvantage of the louver MEMS-based variable emissivity radiator was designed for satellite thermal control. Because of its immediate response and low power consumption. Also MEMS- based variable emissivity radiator has been made smaller by using MEMS process, it could be solved the problem of the increase in weight and volume, and it has a high reliability and immediate response by using electrical control. In this study, operation validation of the MEMS radiator had been carried out, resulting that emissivity could be controlled. Numerical model was also designed to predict the thermal control performance of MEMS-based variable emissivity radiator

  11. MEMS-Based Architecture to Improve Submunition Fuze Safety and Reliability

    National Research Council Canada - National Science Library

    Robinson, C. H; Gelak, M. R; Hoang, T. Q; Wood, R. H

    2004-01-01

    .... The ARDEC Fuze Division is developing a MEMS-based safety and arming architecture for submunition fuzes that will so significantly improve the munition's primary reliability that the need for self-destruct (SD...

  12. Compact, Ultrasensitive Formaldehyde Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop an ultrasensitive, laser-based formaldehyde gas sensor system for airborne and ground-based...

  13. Design Issues for MEMS-Based Pedestrian Inertial Navigation Systems

    Directory of Open Access Journals (Sweden)

    P. S. Marinushkin

    2015-01-01

    Full Text Available The paper describes design issues for MEMS-based pedestrian inertial navigation systems. By now the algorithms to estimate navigation parameters for strap-down inertial navigation systems on the basis of plural observations have been already well developed. At the same time mathematical and software processing of information in the case of pedestrian inertial navigation systems has its specificity, due to the peculiarities of their functioning and exploitation. Therefore, there is an urgent task to enhance existing fusion algorithms for use in pedestrian navigation systems. For this purpose the article analyzes the characteristics of the hardware composition and configuration of existing systems of this class. The paper shows advantages of various technical solutions. Relying on their main features it justifies a choice of the navigation system architecture and hardware composition enabling improvement of the estimation accuracy of user position as compared to the systems using only inertial sensors. The next point concerns the development of algorithms for complex processing of heterogeneous information. To increase an accuracy of the free running pedestrian inertial navigation system we propose an adaptive algorithm for joint processing of heterogeneous information based on the fusion of inertial info rmation with magnetometer measurements using EKF approach. Modeling of the algorithm was carried out using a specially developed functional prototype of pedestrian inertial navigation system, implemented as a hardware/software complex in Matlab environment. The functional prototype tests of the developed system demonstrated an improvement of the navigation parameters estimation compared to the systems based on inertial sensors only. It enables to draw a conclusion that the synthesized algorithm provides satisfactory accuracy for calculating the trajectory of motion even when using low-grade inertial MEMS sensors. The developed algorithm can be

  14. Thermal degradation and evolved gas analysis: A polymeric blend of urea formaldehyde (UF and epoxy (DGEBA resin

    Directory of Open Access Journals (Sweden)

    Tansir Ahamad

    2014-12-01

    Full Text Available A polymeric blend has been prepared using urea formaldehyde (UF and epoxy (DGEBA resin in 1:1 mass ratio. The thermal degradation of UF/epoxy resin blend (UFE was investigated by using thermogravimetric analyses (TGA, coupled with FTIR and MS. The results of TGA revealed that the pyrolysis process can be divided into three stages: drying process, fast thermal decomposition and cracking of the sample. There were no solid products except ash content for UFE during combustion at high temperature. The total mass loss during pyrolysis at 775 °C is found to be 97.32%, while 54.14% of the original mass was lost in the second stage between 225 °C and 400 °C. It is observed that the activation energy of the second stage degradation during combustion (6.23 × 10−4 J mol−1 is more than that of pyrolysis (5.89 × 10−4 J mol−1. The emissions of CO2, CO, H2O, HCN, HNCO, and NH3 are identified during thermal degradation of UFE.

  15. Formaldehyde exposure and patterns of concomitant contact allergy to formaldehyde and formaldehyde-releasers

    DEFF Research Database (Denmark)

    Lundov, Michael D; Johansen, Jeanne D; Carlsen, Berit C

    2010-01-01

    Formaldehyde and formaldehyde-releasers are widely used in consumer products and may often cause contact allergy.......Formaldehyde and formaldehyde-releasers are widely used in consumer products and may often cause contact allergy....

  16. The synthetic evaluation of CuO-MnOx-modified pinecone biochar for simultaneous removal formaldehyde and elemental mercury from simulated flue gas.

    Science.gov (United States)

    Yi, Yaoyao; Li, Caiting; Zhao, Lingkui; Du, Xueyu; Gao, Lei; Chen, Jiaqiang; Zhai, Yunbo; Zeng, Guangming

    2018-02-01

    A series of low-cost Cu-Mn-mixed oxides supported on biochar (CuMn/HBC) synthesized by an impregnation method were applied to study the simultaneous removal of formaldehyde (HCHO) and elemental mercury (Hg 0 ) at 100-300° C from simulated flue gas. The metal loading value, Cu/Mn molar ratio, flue gas components, reaction mechanism, and interrelationship between HCHO removal and Hg 0 removal were also investigated. Results suggested that 12%CuMn/HBC showed the highest removal efficiency of HCHO and Hg 0 at 175° C corresponding to 89%and 83%, respectively. The addition of NO and SO 2 exhibited inhibitive influence on HCHO removal. For the removal of Hg 0 , NO showed slightly positive influence and SO 2 had an inhibitive effect. Meanwhile, O 2 had positive impact on the removal of HCHO and Hg 0 . The samples were characterized by SEM, XRD, BET, XPS, ICP-AES, FTIR, and H 2 -TPR. The sample characterization illustrated that CuMn/HBC possessed the high pore volume and specific surface area. The chemisorbed oxygen (O β ) and the lattice oxygen (O α ) which took part in the removal reaction largely existed in CuMn/HBC. What is more, MnO 2 and CuO (or Cu 2 O) were highly dispersed on the CuMn/HBC surface. The strong synergistic effect between Cu-Mn mixed oxides was critical to the removal reaction of HCHO and Hg 0 via the redox equilibrium of Mn 4+ + Cu + ↔ Mn 3+ + Cu 2+ .

  17. Striping Policy as a Design Parameter for MEMS-based Storage Systems

    NARCIS (Netherlands)

    Khatib, M.G.; van der Zwaag, B.J.; van Viegen, F.C.; Smit, Gerardus Johannes Maria

    2006-01-01

    Storage devices based on MEMS (Micro-Electro-Mechanical Systems) are suitable as secondary storage for future (mobile) computer systems. They are non-volatile and execute a high level of parallelism. In a MEMS-based storage system, many (i.e., 100s or 1000s) read/write heads or probes operate

  18. Fast Configuration of MEMS-Based Storage Devices for Streaming Applications

    NARCIS (Netherlands)

    Khatib, M.G.; van Dijk, H.W.

    2009-01-01

    An exciting class of storage devices is emerging: the class of Micro-Electro-Mechanical storage Systems (MEMS). Properties of MEMS-based storage devices include high density, small form factor, and low power. The use of this type of devices in mobile infotainment systems, such as video cameras is

  19. Policies for Probe-Wear Leveling in MEMS-Based Storage Devices

    NARCIS (Netherlands)

    Khatib, M.G.; Hartel, Pieter H.

    2009-01-01

    Probes (or read/write heads) in MEMS-based storage devices are susceptible to wear. We study probe wear, and analyze the causes of probe uneven wear. We show that under real-world traces some probes can wear one order of magnitude faster than other probes leading to premature expiry of some probes.

  20. MEMS-based wavelength and orbital angular momentum demultiplexer for on-chip applications

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir; Porfirev, Alexey P.; Gurbatov, Stanislav O.

    2017-01-01

    Summary form only given. We demonstrate a new tunable MEMS-based WDM&OAM Fabry-Pérot filter for simultaneous wavelength (WDM) and Orbital Angular Momentum (OAM) (de)multiplexing. The WDM&OAM filter is suitable for dense on-chip integration and dedicated for the next generation of optical...

  1. Method for spatially modulating X-ray pulses using MEMS-based X-ray optics

    Science.gov (United States)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2015-03-10

    A method and apparatus are provided for spatially modulating X-rays or X-ray pulses using microelectromechanical systems (MEMS) based X-ray optics. A torsionally-oscillating MEMS micromirror and a method of leveraging the grazing-angle reflection property are provided to modulate X-ray pulses with a high-degree of controllability.

  2. MEMS-based fuel cells with integrated catalytic fuel processor and method thereof

    Science.gov (United States)

    Jankowski, Alan F [Livermore, CA; Morse, Jeffrey D [Martinez, CA; Upadhye, Ravindra S [Pleasanton, CA; Havstad, Mark A [Davis, CA

    2011-08-09

    Described herein is a means to incorporate catalytic materials into the fuel flow field structures of MEMS-based fuel cells, which enable catalytic reforming of a hydrocarbon based fuel, such as methane, methanol, or butane. Methods of fabrication are also disclosed.

  3. Design and modeling of a precision 6 DOF MEMS-based parallel kinematic TEM sample manipulator

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; de Jong, B.R.; Soemers, Herman

    2006-01-01

    A design for a 6 Degree-of-freedom precision MEMS-based manipulator for a TEM will is presented. The elastic mechanism is designed and modeled with the specific design considerations regarding kinematic constraint design and elastic energy storage. The typical relatively large deformations of

  4. Design and modeling of a six DOF's MEMS-based precision manipulators

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; de Jong, B.R.; Soemers, Herman

    2010-01-01

    In this paper a design is presented for a precision MEMS-based six degrees-of-freedom (DOFs) manipulator. The purpose of the manipulator is to position a small sample (10 μm × 20 μm × 0.2 μm) in a transmission electron microscope. A parallel kinematic mechanism with slanted leaf-springs is used to

  5. A large-stroke planar MEMS-based stage with integrated feedback

    NARCIS (Netherlands)

    Krijnen, B.

    2014-01-01

    Micro-electromechanical systems (MEMS) are all around us nowadays, especially in sensor technology. MEMS-based positioning stages can become favorable in applications where the available volume is small, the response needs to be fast, and the fabrication costs low. This thesis describes the

  6. Formaldehyde in Our Environment.

    Science.gov (United States)

    Ojanlatva, Ansa; Weeks, Charlie A.

    During the energy crisis of the early 1970s, there was a drive to conserve energy in every segment of society. Citizens were encouraged to insulate their homes and tighten them up to avoid loss of energy. One of the products to emerge from this crisis was urea formaldehyde foam insulation. (Urea formaldehyde is a well-known agent for preserving…

  7. The formaldehyde dilemma.

    Science.gov (United States)

    Salthammer, Tunga

    2015-06-01

    The IARC's 2004 classification of formaldehyde as a human carcinogen has led to intensive discussion on scientific and regulatory levels. In June 2014, the European Union followed and classified formaldehyde as a cause of cancer. This automatically triggers consequences in terms of emission minimization and the health-related assessment of building and consumer products. On the other hand, authorities are demanding and authorizing technologies and products which can release significant quantities of formaldehyde into the atmosphere. In the outdoor environment, this particularly applies to combusting fuels. The formation of formaldehyde through photochemical smog has also been a recognized problem for years. Indoors there are various processes which can contribute to increased formaldehyde concentrations. Overall, legislation faces a dilemma: primary sources are often over-regulated while a lack of consideration of secondary sources negates the regulations' effects. Copyright © 2015 Elsevier GmbH. All rights reserved.

  8. MEMS-based platforms for mechanical manipulation and characterization of cells

    Science.gov (United States)

    Pan, Peng; Wang, Wenhui; Ru, Changhai; Sun, Yu; Liu, Xinyu

    2017-12-01

    Mechanical manipulation and characterization of single cells are important experimental techniques in biological and medical research. Because of the microscale sizes and highly fragile structures of cells, conventional cell manipulation and characterization techniques are not accurate and/or efficient enough or even cannot meet the more and more demanding needs in different types of cell-based studies. To this end, novel microelectromechanical systems (MEMS)-based technologies have been developed to improve the accuracy, efficiency, and consistency of various cell manipulation and characterization tasks, and enable new types of cell research. This article summarizes existing MEMS-based platforms developed for cell mechanical manipulation and characterization, highlights their specific design considerations making them suitable for their designated tasks, and discuss their advantages and limitations. In closing, an outlook into future trends is also provided.

  9. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  10. A Simple Model for Complex Fabrication of MEMS based Pressure Sensor: A Challenging Approach

    Directory of Open Access Journals (Sweden)

    Himani SHARMA

    2010-08-01

    Full Text Available In this paper we have presented the simple model for complex fabrication of MEMS based absolute micro pressure sensor. This kind of modeling is extremely useful for determining its complexity in fabrication steps and provides complete information about process sequence to be followed during manufacturing. Therefore, the need for test iteration decreases and cost, time can be reduced significantly. By using DevEdit tool (part of SILVACO tool, a behavioral model of pressure sensor have been presented and implemented.

  11. Formaldehyde-releasers : relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    NARCIS (Netherlands)

    de Groot, Anton C.; Flyvholm, Mari-ann; Lensen, Gerda; Menne, Torkil; Coenraads, Pieter-Jan

    2009-01-01

    This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the

  12. Occupational contact allergy to formaldehyde and formaldehyde releasers.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Kuuliala, O; Suuronen, K; Alanko, K

    2008-11-01

    Formaldehyde allergy is common and usually derives from formaldehyde-releasing biocides in cosmetic and other products. To analyse patterns of patch test reactions to formaldehyde and formaldehyde-releasing compounds and the sources of sensitization. At the Finnish Institute of Occupational Health, we screened the patch test files for allergic reactions to formaldehyde and 12 formaldehyde-releasing compounds. All patients with contact allergy to any of the substances were included, and their records were reviewed. Between January 2001 and May 2007, we had patch tested 81 patients with formaldehyde allergy and 18 with independent allergy to some formaldehyde releaser. Of the formaldehyde allergies, 60 were new sensitizations, 25 of which were considered to be occupational. The most common source of occupational sensitization was metalworking fluids followed by creams and related products. Exposure to formaldehyde-releasing preservatives in liquid soaps and other rinse-off products was common in both occupational and non-occupational cases. Reactions to formaldehyde-releasing compounds were seen in 79% of the formaldehyde-allergic patients. Occupational formaldehyde allergy was common and occurred in metalworkers, hairdressers, masseurs, and workers using protective creams, detergents, and liquid soaps. When compared with studies on general dermatological patients, contact allergy to formaldehyde releasers without formaldehyde allergy was rare.

  13. Formaldehyde Workshop Agenda

    Science.gov (United States)

    This is the agenda for the Formaldehyde Workshop hosted by the Office of Research and Development's National Center for Environmental Assessments in cooperation with the IRIS Program. The workshop was held in April 2014

  14. Design and fabrication of a flexible MEMS-based electromechanical sensor array for breast cancer diagnosis.

    Science.gov (United States)

    Pandya, Hardik J; Park, Kihan; Desai, Jaydev P

    2015-06-23

    The use of flexible micro-electro-mechanical systems (MEMS) based device provides a unique opportunity in bio-medical robotics such as characterization of normal and malignant tissues. This paper reports on design and development of a flexible MEMS-based sensor array integrating mechanical and electrical sensors on the same platform to enable the study of the change in electro-mechanical properties of the benign and cancerous breast tissues. In this work, we present the analysis for the electrical characterization of the tissue specimens and also demonstrate the feasibility of using the sensor for mechanical characterization of the tissue specimens. Eight strain gauges acting as mechanical sensors were fabricated using poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) conducting polymer on poly(dimethylsiloxane) (PDMS) as the substrate material. Eight electrical sensors were fabricated using SU-8 pillars on gold (Au) pads which were patterned on the strain gauges separated by a thin insulator (SiO 2 1.0μm). These pillars were coated with gold to make it conducting. The electromechanical sensors are integrated on the same substrate. The sensor array covers 180μm × 180μm area and the size of the complete device is 20mm in diameter. The diameter of each breast tissue core used in the present study was 1mm and the thickness was 8μm. The region of interest was 200μm × 200μm. Microindentation technique was used to characterize the mechanical properties of the breast tissues. The sensor is integrated with conducting SU-8 pillars to study the electrical property of the tissue. Through electro-mechanical characterization studies using this MEMS-based sensor, we were able to measure the accuracy of the fabricated device and ascertain the difference between benign and cancer breast tissue specimens.

  15. Fast Configuration of MEMS-Based Storage Devices for Streaming Applications

    OpenAIRE

    Khatib, M.G.; van Dijk, H.W.

    2009-01-01

    An exciting class of storage devices is emerging: the class of Micro-Electro-Mechanical storage Systems (MEMS). Properties of MEMS-based storage devices include high density, small form factor, and low power. The use of this type of devices in mobile infotainment systems, such as video cameras is not at all obvious. We must explore their configuration and assess their benefit with respect to existing devices, such as Flash. In this paper, we study the configuration of the data layout of MEMS-...

  16. MEMS-based system and image processing strategy for epiretinal prosthesis.

    Science.gov (United States)

    Xia, Peng; Hu, Jie; Qi, Jin; Gu, Chaochen; Peng, Yinghong

    2015-01-01

    Retinal prostheses have the potential to restore some level of visual function to the patients suffering from retinal degeneration. In this paper, an epiretinal approach with active stimulation devices is presented. The MEMS-based processing system consists of an external micro-camera, an information processor, an implanted electrical stimulator and a microelectrode array. The image processing strategy combining image clustering and enhancement techniques was proposed and evaluated by psychophysical experiments. The results indicated that the image processing strategy improved the visual performance compared with direct merging pixels to low resolution. The image processing methods assist epiretinal prosthesis for vision restoration.

  17. Formaldehyde-releasers: relationship to formaldehyde contact allergy. Contact allergy to formaldehyde and inventory of formaldehyde-releasers

    DEFF Research Database (Denmark)

    de Groot, Anton C; Flyvholm, Mari-Ann; Lensen, Gerda

    2009-01-01

    This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed in the liter......This is one of series of review articles on formaldehyde and formaldehyde-releasers (others: formaldehyde in cosmetics, in clothes and in metalworking fluids and miscellaneous). Thirty-five chemicals were identified as being formaldehyde-releasers. Although a further seven are listed...... of sensitization, relevance of positive patch test reactions, clinical pattern of allergic contact dermatitis from formaldehyde, prognosis, threshold for elicitation of allergic contact dermatitis, analytical tests to determine formaldehyde in products and frequency of exposure to formaldehyde and releasers....... The frequency of contact allergy to formaldehyde is consistently higher in the USA (8-9%) than in Europe (2-3%). Patch testing with formaldehyde is problematic; the currently used 1% solution may result in both false-positive and false-negative (up to 40%) reactions. Determining the relevance of patch test...

  18. Eerste inventarisatie alternatieven voor biociden met formaldehyde of formaldehyde releasers

    NARCIS (Netherlands)

    Wezenbeek JJ; Janssen MPM; Scheepmaker JWA; MSP; M&V

    2015-01-01

    Formaldehyde is de werkzame stof in veel desinfecteer- en conserveringsmiddelen, maar deze stof is kankerverwekkend. Daarom zal formaldehyde naar verwachting per 1 januari 2016 op Europees niveau als zodanig worden geclassificeerd (carcinogeen 1B). Dit kan betekenen dat formaldehyde-houdende

  19. Analysis of a novel MEMS-based design of micro-direct methanol fuel cell

    Science.gov (United States)

    Chen, Falin; Chang, Min-Hsing; Lin, Hung-Yi.

    A theoretical analysis is performed in this study for a novel MEMS-based design of micro-direct methanol fuel cell which was proposed by Motokawa et al. [S. Motokawa, M. Mohamedi, T. Momma, J. Electrochem. Commun. 6 (2004) 562-565]. The system comprises two parallel microchannels and is fabricated by a series of steps of MEMS techniques. The methanol stream occupies one channel as fuel and the saturated oxygen liquid stream flows in the other channel as oxidant. Both reactants are dissolved in dilute sulfuric acid solution. The top of the system is covered by a layer of Nafion membrane as the electrolyte layer. Such a novel design eliminates the complicated water management problem and could potentially enhance the volume power density. The cell performance is investigated in detail by examining the effects of several system parameters. The present results provide significant physical insights for the system and benefit the further optimal design of this novel MEMS-based design of microfuel cell for the fulfillment of practice application in portable power sources.

  20. MEMS-based sensing and algorithm development for fall detection and gait analysis

    Science.gov (United States)

    Gupta, Piyush; Ramirez, Gabriel; Lie, Donald Y. C.; Dallas, Tim; Banister, Ron E.; Dentino, Andrew

    2010-02-01

    Falls by the elderly are highly detrimental to health, frequently resulting in injury, high medical costs, and even death. Using a MEMS-based sensing system, algorithms are being developed for detecting falls and monitoring the gait of elderly and disabled persons. In this study, wireless sensors utilize Zigbee protocols were incorporated into planar shoe insoles and a waist mounted device. The insole contains four sensors to measure pressure applied by the foot. A MEMS based tri-axial accelerometer is embedded in the insert and a second one is utilized by the waist mounted device. The primary fall detection algorithm is derived from the waist accelerometer. The differential acceleration is calculated from samples received in 1.5s time intervals. This differential acceleration provides the quantification via an energy index. From this index one may ascertain different gait and identify fall events. Once a pre-determined index threshold is exceeded, the algorithm will classify an event as a fall or a stumble. The secondary algorithm is derived from frequency analysis techniques. The analysis consists of wavelet transforms conducted on the waist accelerometer data. The insole pressure data is then used to underline discrepancies in the transforms, providing more accurate data for classifying gait and/or detecting falls. The range of the transform amplitude in the fourth iteration of a Daubechies-6 transform was found sufficient to detect and classify fall events.

  1. Method of forming a package for MEMS-based fuel cell

    Science.gov (United States)

    Morse, Jeffrey D; Jankowski, Alan F

    2013-05-21

    A MEMS-based fuel cell package and method thereof is disclosed. The fuel cell package comprises seven layers: (1) a sub-package fuel reservoir interface layer, (2) an anode manifold support layer, (3) a fuel/anode manifold and resistive heater layer, (4) a Thick Film Microporous Flow Host Structure layer containing a fuel cell, (5) an air manifold layer, (6) a cathode manifold support structure layer, and (7) a cap. Fuel cell packages with more than one fuel cell are formed by positioning stacks of these layers in series and/or parallel. The fuel cell package materials such as a molded plastic or a ceramic green tape material can be patterned, aligned and stacked to form three dimensional microfluidic channels that provide electrical feedthroughs from various layers which are bonded together and mechanically support a MEMS-based miniature fuel cell. The package incorporates resistive heating elements to control the temperature of the fuel cell stack. The package is fired to form a bond between the layers and one or more microporous flow host structures containing fuel cells are inserted within the Thick Film Microporous Flow Host Structure layer of the package.

  2. Formaldehyde: a candidate toxic air contaminant. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Frye, B.; Parker, T.

    1988-03-01

    Formaldehyde (HCHO) is a gas widely used in adhesives and resins, textiles, embalming fluids, fungicides, air fresheners, and cosmetics. It is directly emitted into the ambient outdoor air from vehicular and stationary sources, and is also produced in the atmosphere from other substances by photochemical smog processes. The International Agency for Research on Cancer (IARC) has determined that there is sufficient evidence for carcinogenicity of formaldehyde to animals, and limited evidence for carcinogenicity to humans. EPA classifies formaldehyde as a probable human carcinogen with a one in a million risk concentration of 0.08 ppb.

  3. Separation of emitted and photochemical formaldehyde in Mexico City using a statistical analysis and a new pair of gas-phase tracers

    Directory of Open Access Journals (Sweden)

    A. R. Garcia

    2006-01-01

    Full Text Available Photochemical pollution control strategies require an understanding of photochemical oxidation precursors, making it important to distinguish between primary and secondary sources of HCHO. Estimates for the relative strengths of primary and secondary sources of formaldehyde (HCHO were obtained using a statistical regression analysis with time series data of carbon monoxide (CO and glyoxal (CHOCHO measured in the Mexico City Metropolitan Area (MCMA during the spring of 2003. Differences between Easter week and more typical weeks are evaluated. The use of CO-CHOCHO as HCHO tracers is more suitable for differentiating primary and secondary sources than CO-O3. The application of the CO-O3 tracer pair to mobile laboratory data suggests a potential in-city source of background HCHO. A significant amount of HCHO observed in the MCMA is associated with primary emissions.

  4. Initial Measurements of Radiocarbon In Atmospheric Formaldehyde at Narragansett, RI

    Science.gov (United States)

    Shen, H.; Heikes, B. G.; Xu, L.; McNichol, A. P.; Olson, J. R.

    2008-12-01

    Formaldehyde is an intermediate in the atmospheric oxidation of nearly every volatile organic compound (VOC) and is important to odd-hydrogen radicals and ozone chemistry. It is directly observed from space and its distributions are used to constrain biogenic emissions of VOCs, specifically isoprene. The relative contribution of fossil VOCs and biogenic VOCs to formaldehyde, to isoprene emission estimates and subsequently to ozone and oxidant chemistry is expected to vary seasonally and spatially due to VOC speciation, emission patterns, and reactivity. The radiocarbon, 14C, content of formaldehyde is useful in assessing the relative contributions of fossil and biogenic VOC groups to formaldehyde. We report a compound specific radiocarbon analysis (CSRA) method for formaldehyde based upon gaseous formaldehyde collection, derivatization to thiazolidine, preparative capillary gas chromatography separation, and AMS analysis. Ambient measurements from Narragansett, RI, made in winter and summer 2007 are presented. On 11 of 13 samples, we find 80 to >95% of the collected formaldehyde is of fossil origin and, contrary to our initial hypothesis, we see no seasonal shift in proportion. The remaining 2 samples, one each from winter and summer, are 30-40% biogenic carbon. The measurements are interpreted considering fossil-biogenic source attribution and local transport conditions and contrasted with prior measurements from Nova Scotia. Further, CSRA measurement of acetaldehyde is feasible with the method.

  5. Design and analysis of a MEMS-based bifurcate-shape piezoelectric energy harvester

    Directory of Open Access Journals (Sweden)

    Yuan Luo

    2016-04-01

    Full Text Available This paper presents a novel piezoelectric energy harvester, which is a MEMS-based device. This piezoelectric energy harvester uses a bifurcate-shape. The derivation of the mathematical modeling is based on the Euler-Bernoulli beam theory, and the main mechanical and electrical parameters of this energy harvester are analyzed and simulated. The experiment result shows that the maximum output voltage can achieve 3.3V under an acceleration of 1g at 292.11Hz of frequency, and the output power can be up to 0.155mW under the load of 0.4MΩ. The power density is calculated as 496.79μWmm−3. Besides that, it is demonstrated efficiently at output power and voltage and adaptively in practical vibration circumstance. This energy harvester could be used for low-power electronic devices.

  6. Preliminary Performance Evaluation of MEMS-based Piezoelectric Energy Harvesters in Extended Temperature Range

    DEFF Research Database (Denmark)

    Xu, R.; Borregaard, L.M.; Lei, A.

    2012-01-01

    In this work a batch of MEMS-based vibration energy harvesters consisting of a silicon/PZT thick film ntilever with integrated proof mass is characterized. The purpose of a vibration energy harvester is to convert low grade vibrations to useful electrical power. Optimally, the natural frequency...... of the harvester should match the frequency of he ambient vibration. The first step to achieve this is to evaluate the uniformity of the fabricated harvesters and nderstand the effects of temperature on the harvesters during operation. Therefore, the uniformity of 40 energy harvesters from one wafer has been...... evaluated. Thereafter the performance of the energy harvesters operating at emperatures between -30°C to 100°C was measured....

  7. Homogeneity Analysis of a MEMS-based PZT Thick Film Vibration Energy Harvester Manufacturing Process

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Borregaard, Louise M.

    2012-01-01

    This paper presents a homogeneity analysis of a high yield wafer scale fabrication of MEMS-based unimorph silicon/PZT thick film vibration energy harvesters aimed towards vibration sources with peak vibrations in the range of around 300Hz. A wafer with a yield of 91% (41/45 devices) has been...... indicating that the main variation in open circuit voltage performance is caused by varying quality factor. The average resonant frequency was measured to 333Hz with a standard variation of 9.8Hz and a harvesting bandwidth of 5-10Hz. A maximum power output of 39.3μW was achieved at 1g for the best performing...... harvester....

  8. Fabrication and Analysis of Tapered Tip Silicon Microneedles for MEMS based Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Muhammad Waseem Ashraf

    2010-11-01

    Full Text Available In this paper, a novel design of transdermal drug delivery (TDD system is presented. The proposed system consists of controlled electronic circuit and microelectromechanical system (MEMS based devices like microneedles, micropump, flow sensor, and blood pressure sensor. The aim of this project is to develop a system that can eliminate the limitations associated with oral therapy. In this phase tapered tip silicon microneedles have been fabricated using inductively coupled plasma (ICP etching technology. Using ANSYS, simulation of microneedles has been conducted before the fabrication process to test the design suitability for TDD. More over multifield analysis of reservoir integrated with microneedle array using piezoelectric actuator has also been performed. The effects of frequency and voltage on actuator and fluid flow rate through 6×6 microneedle array have been investigated. This work provides envisage data to design suitable devices for TDD.

  9. Compact MEMS-based Adaptive Optics Optical Coherence Tomography for Clinical Use

    Energy Technology Data Exchange (ETDEWEB)

    Chen, D; Olivier, S; Jones, S; Zawadzki, R; Evans, J; Choi, S; Werner, J

    2008-02-04

    We describe a compact MEMS-based adaptive optics (AO) optical coherence tomography system with improved AO performance and ease of clinical use. A typical AO system consists of a Shack-Hartmann wavefront sensor and a deformable mirror that measures and corrects the ocular and system aberrations. Because of the limitation on the current deformable mirror technologies, the amount of real-time ocular-aberration compensation is restricted and small in the previous AO-OCT instruments. In this instrument, we proposed to add an optical apparatus to correct the spectacle aberrations of the patients such as myopia, hyperopia and astigmatism. This eliminated the tedious process of the trial lenses in clinical imaging. Different amount of spectacle aberration compensation was achieved by motorized stages and automated with the AO computer for ease of clinical use. In addition, the compact AO-OCT was optimized to have minimum system aberrations to reduce AO registration errors and improve AO performance.

  10. MEMS-based optical mini- and microspectrometers for the visible and infrared spectral range

    Science.gov (United States)

    Wolffenbuttel, R. F.

    2005-07-01

    Miniaturized free-field based optical microspectrometers have huge potential for application in industry, science, medicine, agriculture and biology. State-of-the-art is the micro-assembly of micromachined optical components on a mini-bench and the trend is towards fully integrated optical microsystems. Complete silicon IC compatible MEMS-based opto-electrical microsystems on a single chip may offer huge cost benefits in these potentially high-volume applications. On-chip integration does, however, impose limitations. The required process compatibility and limited choice of acceptable materials does not necessarily give optimum optical performance. Also, the dimensional downscaling is not generally an optical advantage. This overview discusses grating-based and interferometer-based mini- and microspectrometers, shows performances already reported, the trends, the potential, the limitations and approaches to obtain a sufficient optical performance, in terms of spectral resolution and throughput, for serving the majority of applications.

  11. Compact MEMS-based adaptive optics: optical coherence tomography for clinical use

    Science.gov (United States)

    Chen, Diana C.; Olivier, Scot S.; Jones, Steven M.; Zawadzki, Robert J.; Evans, Julia W.; Choi, Stacey S.; Werner, John S.

    2008-02-01

    We describe a compact MEMS-based adaptive optics (AO) optical coherence tomography (OCT) system with improved AO performance and ease of clinical use. A typical AO system consists of a Shack-Hartmann wavefront sensor and a deformable mirror that measures and corrects the ocular and system aberrations. Because of limitations on current deformable mirror technologies, the amount of real-time ocular-aberration compensation is restricted and small in previous AO-OCT instruments. In this instrument, we incorporate an optical apparatus to correct the spectacle aberrations of the patients such as myopia, hyperopia and astigmatism. This eliminates the tedious process of using trial lenses in clinical imaging. Different amount of spectacle aberration compensation was achieved by motorized stages and automated with the AO computer for ease of clinical use. In addition, the compact AO-OCT was optimized to have minimum system aberrations to reduce AO registration errors and improve AO performance.

  12. RF MEMS Based Tunable Bandpass Filter For X-Band Applications

    Science.gov (United States)

    Chaubey, Mahesh Kumar; Bhadauria, Avanish

    2018-03-01

    In this paper, we present the design and simulation of RF MEMS based Tunable combline band pass filters for X-band applications at different substrate thicknesses and studied the effect of thickness on tuning. The proposed filters are designed on high resistive silicon substrate of 500µm and 300 thicknesses. The tunability is achieved by using MEMS based varacter replaced with fix capacitor in conventional combline filter. First, the microstrip combline filter is designed at the centre frequency of 9.5 GHz and then tuning is achieved by varying the capacitance in the designed combline filters. The electromagnetic simulation has been carried out using HFSS v15 software based on finite element method (FEM). The tuning of the filter on silicon substrate of 500 μm is achieved by changing the capacitance value from 0.2035 pF to 0.4035 pF in the model in HFSS, which resulted the tuning in the frequency range of 7.85 to 10.35GHz. Insertion loss of design filter is in the range of 1dB within the tuning range. In case of substrate thickness 300 μm the tuning of the filter is achieved by changing the capacitance value from 0.293 pF to 0.403 pF in the model in HFSS, which resulted the tuning in the frequency range of 8.80 to 9.90 GHz. Insertion loss of design filter is in the range of ∼1.2dB within the tuning range.

  13. Effect of cultivar and formaldehyde treatment of barley grain on ...

    African Journals Online (AJOL)

    ... but increased the time (h) to produce 50% of A and reduced the time (h) to produce 95% of A. The reduction in gas production ranged from 33.3 to 51 mL/g OM with 6 h incubation showing the highest decrease in gas production. It is concluded that formaldehyde treatment may provide an opportunity to manipulate the site ...

  14. Formaldehyde in reusable protective gloves.

    Science.gov (United States)

    Pontén, Ann

    2006-05-01

    Due to the clinical findings in a single patient's case, formaldehyde was suspected to be present in clinically relevant levels in reusable protective gloves. Therefore, 9 types of gloves were investigated with the semi-quantitative chromotropic acid method. It was found that 6/9 gloves emitted some formaldehyde and that 4/9 gloves emitted > or =40 microg of formaldehyde. Most of the formaldehyde was found on the inside of the gloves. To get an indication of the clinical relevance, a comparison with a protective cream declared to contain the formaldehyde-releasing agent diazolidinyl urea was performed by comparing areas of gloves with areas of cream layers with thickness 1-2 mg/cm(2). It was found that the amounts of formaldehyde emitted from the gloves might be in the same range as emitted from a layer of cream.

  15. Emission of formaldehyde from furniture

    DEFF Research Database (Denmark)

    Andersen, Helle Vibeke; Klinke, Helene B.; Funch, Lis Winther

    The emission of formaldehyde from 20 pieces of furniture, representing a variety of types, was measured in climate chambers. Most tests show low emissions but certain scenarios of furnishing, including furniture with large surface areas in relation to room volume can emit formaldehyde resulting...

  16. Primary Formation Path of Formaldehyde in Hydrothermal Vents

    Science.gov (United States)

    Inaba, Satoshi

    2018-03-01

    Formaldehyde is abundant in the universe and one of the fundamental molecules for life. Hydrothermal vents produce a substantial amount of hydrogen molecules by serpentinization and promote reductive reactions of single carbon compounds. The abundance of formaldehyde is expected to be low due to the high Gibbs free energy in hydrothermal vents. We consider two competing formation pathways of formaldehyde: (1) the reduction of CO by H2 and (2) the reduction of HCOOH by H2 to form a methanediol, followed by the dehydration of the methanediol. We performed a number of quantum chemical simulations to examine the formation of formaldehyde in the gas phase as well as in aqueous solution. The energy barrier is significantly reduced by the catalytic effect of water molecules in aqueous solution and becomes lowest when a water cluster consisted of 5 water molecules catalyzes the reduction. The energy barrier to form a methanediol by the reduction of HCOOH is lower by 17.5 kcal/mol than that to form a formaldehyde by the reduction of CO. Considering the low energy barrier to dehydrate methanediol, the primary pathway to form formaldehyde in hydrothermal vents is concluded to be the reduction of HCOOH by H2, followed by the dehydration of methanediol.

  17. Association between formaldehyde exposure and miscarriage in Chinese women.

    Science.gov (United States)

    Xu, Wenjing; Zhang, Weiqiang; Zhang, Xuezhen; Dong, Taowei; Zeng, Huiqian; Fan, Qiyun

    2017-06-01

    The aim of this study was to assess whether higher plasma formaldehyde concentration existed in women diagnosed with miscarriage and whether it contributed to higher risk of miscarriage in Chinese women.A case-control study was conducted in 118 women with a diagnosed miscarriage at the first trimester and 191 healthy women who delivered at term. Plasma levels of formaldehyde were measured by gas chromatography in conjunction with mass spectrometry after derivatization of the formaldehyde to the pentafluorophenylhydrazone and characteristics of the subjects including age, education level, occupation, family income, home decoration status, and exposure to second-hand smoke were recorded. Logistic regression analyses were performed to investigate the relationship between miscarriage and levels of formaldehyde.Women with miscarriage were comparable to controls in terms of age, education level, occupation, family income, and home decoration status. They were, however, more likely to be exposed to second-hand smoke. Plasma levels of formaldehyde were significantly higher in women with miscarriage (0.0944 ± 0.0105 vs. 0.0239 ± 0.0032 μg/mL, P formaldehyde (odds ratio [OR]: 8.06, 95% confidence interval [CI]: 4.96-13.09) and exposure to second-hand smoke (OR: 3.60, 95% CI: 1.58-8.20) were independently and significantly associated with higher risk of miscarriage.Plasma levels of formaldehyde were significantly higher in women who were diagnosed with miscarriage than those who delivered at term and higher levels of formaldehyde was an independent risk factor for miscarriage, with higher levels being associated with higher risk of miscarriage.

  18. Simultaneous wavelength and orbital angular momentum demultiplexing using tunable MEMS-based Fabry-Perot filter

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir; Porfirev, Alexey P.; Gurbatov, Stanislav O.

    2017-01-01

    In this paper, we experimentally demonstrate simultaneous wavelength and orbital angular momentum (OAM) multiplexing/demultiplexing of 10 Gbit/s data streams using a new on-chip micro-component-tunable MEMS-based Fabry-Perot filter integrated with a spiral phase plate. In the experiment, two......B at the harddecision forward-error correction (HD-FEC) bit-error-rate (BER) limit 3.8 × 10□3 when multiplexing a Gaussian beam and OAM beams of azimuthal orders 1, 2 and 3 respectively. In case of phase modulation, power penalties do not exceed 1.77, 0.54 and 0.79 dB respectively. At the 0.4 nm wavelength grid......, maximum power penalties at the HD-FEC BER threshold relative to the 0.8 nm wavelength spacing read 0.83, 0.84 and 1.15 dB when multiplexing a Gaussian beam and OAM beams of 1st, 2nd and 3rd orders respectively. The novelty and impact of the proposed filter design is in providing practical, integrable...

  19. Laboratory validation of MEMS-based sensors for post-earthquake damage assessment image

    Science.gov (United States)

    Pozzi, Matteo; Zonta, Daniele; Santana, Juan; Colin, Mikael; Saillen, Nicolas; Torfs, Tom; Amditis, Angelos; Bimpas, Matthaios; Stratakos, Yorgos; Ulieru, Dumitru; Bairaktaris, Dimitirs; Frondistou-Yannas, Stamatia; Kalidromitis, Vasilis

    2011-04-01

    The evaluation of seismic damage is today almost exclusively based on visual inspection, as building owners are generally reluctant to install permanent sensing systems, due to their high installation, management and maintenance costs. To overcome this limitation, the EU-funded MEMSCON project aims to produce small size sensing nodes for measurement of strain and acceleration, integrating Micro-Electro-Mechanical Systems (MEMS) based sensors and Radio Frequency Identification (RFID) tags in a single package that will be attached to reinforced concrete buildings. To reduce the impact of installation and management, data will be transmitted to a remote base station using a wireless interface. During the project, sensor prototypes were produced by assembling pre-existing components and by developing ex-novo miniature devices with ultra-low power consumption and sensing performance beyond that offered by sensors available on the market. The paper outlines the device operating principles, production scheme and working at both unit and network levels. It also reports on validation campaigns conducted in the laboratory to assess system performance. Accelerometer sensors were tested on a reduced scale metal frame mounted on a shaking table, back to back with reference devices, while strain sensors were embedded in both reduced and full-scale reinforced concrete specimens undergoing increasing deformation cycles up to extensive damage and collapse. The paper assesses the economical sustainability and performance of the sensors developed for the project and discusses their applicability to long-term seismic monitoring.

  20. MEMS Based Broadband Piezoelectric Ultrasonic Energy Harvester (PUEH) for Enabling Self-Powered Implantable Biomedical Devices

    Science.gov (United States)

    Shi, Qiongfeng; Wang, Tao; Lee, Chengkuo

    2016-01-01

    Acoustic energy transfer is a promising energy harvesting technology candidate for implantable biomedical devices. However, it does not show competitive strength for enabling self-powered implantable biomedical devices due to two issues – large size of bulk piezoelectric ultrasound transducers and output power fluctuation with transferred distance due to standing wave. Here we report a microelectromechanical systems (MEMS) based broadband piezoelectric ultrasonic energy harvester (PUEH) to enable self-powered implantable biomedical devices. The PUEH is a microfabricated lead zirconate titanate (PZT) diaphragm array and has wide operation bandwidth. By adjusting frequency of the input ultrasound wave within the operation bandwidth, standing wave effect can be minimized for any given distances. For example, at 1 cm distance, power density can be increased from 0.59 μW/cm2 to 3.75 μW/cm2 at input ultrasound intensity of 1 mW/cm2 when frequency changes from 250 to 240 kHz. Due to the difference of human body and manual surgical process, distance fluctuation for implantable biomedical devices is unavoidable and it strongly affects the coupling efficiency. This issue can be overcome by performing frequency adjustment of the PUEH. The proposed PUEH shows great potential to be integrated on an implanted biomedical device chip as power source for various applications. PMID:27112530

  1. MEMS-based Ni-B probe with enhanced mechanical properties for fine pitch testing

    Science.gov (United States)

    Kim, Kyongtae; Kwon, Hong-Beom; Ahn, Hye-Rin; Kim, Yong-Jun

    2017-12-01

    We fabricated and characterized microelectromechanical systems (MEMS)-based Ni-B probes with enhanced mechanical properties for fine pitch testing. The Ni-B micro-probes were compared with conventional Ni-Co micro-probes in terms of the mechanical performance and thermal effect. The elastic modulus and hardness of Ni-B were found to be 240.4 and 10.9 GPa, respectively, which surpass those of Ni-Co. The Ni-B micro-probes had a higher contact force than the Ni-Co micro-probes by an average of 41.38% owing to the higher elastic modulus. The Ni-B micro-probes had a lower average permanent deformation than the Ni-Co micro-probes after the same overdrive was applied for 1 h by 56.58 µm. The temperature was found to have a negligible effect on the Ni-B micro-probes. These results show that Ni-B micro-probes are useful for fine pitch testing and a potential candidate for replacing conventional Ni-Co micro-probes owing to their advanced mechanical and thermal characteristics.

  2. MEMS-based dynamic cell-to-cell culture platforms using electrochemical surface modifications

    International Nuclear Information System (INIS)

    Chang, Jiyoung; Lin, Liwei; Yoon, Sang-Hee; Mofrad, Mohammad R K

    2011-01-01

    MEMS-based biological platforms with the capability of both spatial placements and time releases of living cells for cell-to-cell culture experiments have been designed and demonstrated utilizing electrochemical surface modification effects. The spatial placement is accomplished by electrochemical surface modification of substrate surfaces to be either adhesive or non-adhesive for living cells. The time control is achieved by the electrical activation of the selective indium tin oxide co-culture electrode to allow the migration of living cells onto the electrode to start the cell-to-cell culture studies. Prototype devices have a three-electrode design with an electrode size of 50 × 50 µm 2 and the separation gaps of 2 µm between them. An electrical voltage of −1.5 V has been used to activate the electrodes independently and sequentially to demonstrate the dynamic cell-to-cell culture experiments of NIH 3T3 fibroblast and Madin Darby canine kidney cells. As such, this MEMS platform could be a basic yet versatile tool to characterize transient cell-to-cell interactions

  3. Evaluation of MEMS-Based Wireless Accelerometer Sensors in Detecting Gear Tooth Faults in Helicopter Transmissions

    Science.gov (United States)

    Lewicki, David George; Lambert, Nicholas A.; Wagoner, Robert S.

    2015-01-01

    The diagnostics capability of micro-electro-mechanical systems (MEMS) based rotating accelerometer sensors in detecting gear tooth crack failures in helicopter main-rotor transmissions was evaluated. MEMS sensors were installed on a pre-notched OH-58C spiral-bevel pinion gear. Endurance tests were performed and the gear was run to tooth fracture failure. Results from the MEMS sensor were compared to conventional accelerometers mounted on the transmission housing. Most of the four stationary accelerometers mounted on the gear box housing and most of the CI's used gave indications of failure at the end of the test. The MEMS system performed well and lasted the entire test. All MEMS accelerometers gave an indication of failure at the end of the test. The MEMS systems performed as well, if not better, than the stationary accelerometers mounted on the gear box housing with regards to gear tooth fault detection. For both the MEMS sensors and stationary sensors, the fault detection time was not much sooner than the actual tooth fracture time. The MEMS sensor spectrum data showed large first order shaft frequency sidebands due to the measurement rotating frame of reference. The method of constructing a pseudo tach signal from periodic characteristics of the vibration data was successful in deriving a TSA signal without an actual tach and proved as an effective way to improve fault detection for the MEMS.

  4. Performance and characterization of a MEMS-based device for alignment and manipulation of x-ray nanofocusing optics

    Directory of Open Access Journals (Sweden)

    Weihe Xu

    2015-03-01

    Full Text Available X-ray microscopy is a powerful, non-invasive tool used for nanometer-scale resolution imaging, and it is widely applied in various areas of science and technology. To push the spatial resolution of x-ray microscopy studies in the hard x-ray regime below 10 nm, Multilayer Laue Lenses (MLL can be used as nanofocusing elements. To ensure distortion-free x-ray imaging, high-stability microscopy systems are required. MEMS-based manipulators are a promising route to achieve high stability when used for alignment and manipulation of nanofocusing optics. In this work, we present a tip-tilt MEMS-based device suitable for MLL alignment. We fully characterize the device and demonstrate better-than 10 millidegree angular positioning resolution when utilizing capacitive displacement sensors, and better-than 0.8 millidegree resolution when using laser interferometry.

  5. Effects of the nanoimprint pattern on the performance of a MEMS-based micro direct methanol fuel cell

    Science.gov (United States)

    Zhang, Yi; Lu, Jian; Zhou, Haoshen; Itoh, Toshihiro; Maeda, Ryutaro

    2009-01-01

    In this paper, nanoimprint technology is presented as an excellent candidate for replacing conventional graphite-based porous electrodes for a more compact and thinner micro direct methanol fuel cell (DMFC). High catalyst efficiency is realized in a MEMS-based passive micro DMFC by directly forming fine patterns on a polymer electrolyte membrane by the nanoimprint method. The MEMS-based micro DMFC has a maximum power density (MPD) of about 0.2 mW cm-2 with a Pt catalyst loading of about 0.04 mg cm-2. The MPD is much higher than those of the reported micro DMFCs with similar catalyst loading. We also investigated the relationship between the cell performance, the nanoimprinted patterns and the catalyst. A good match is necessary between the nanoimprinted patterns and the catalyst layer for high catalyst efficiency. It is mainly owing to the fact that the Pt catalyst layer plays the function of a current collector in the prepared MEMS-based micro DMFC. Higher performance could be enabled by improving the catalyst layer and the nanoimprinted patterns.

  6. Error and Performance Analysis of MEMS-based Inertial Sensors with a Low-cost GPS Receiver

    Directory of Open Access Journals (Sweden)

    Yang Gao

    2008-03-01

    Full Text Available Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS, have been widely utilized and their applications are becoming popular, not only in military or commercial applications, but also for everyday life. Although GPS measurements are the essential information for currently developed land vehicle navigation systems (LVNS, GPS signals are often unavailable or unreliable due to signal blockages under certain environments such as urban canyons. This situation must be compensated in order to provide continuous navigation solutions. To overcome the problems of unavailability and unreliability using GPS and to be cost and size effective as well, Micro Electro Mechanical Systems (MEMS based inertial sensor technology has been pushing for the development of low-cost integrated navigation systems for land vehicle navigation and guidance applications. This paper will analyze the characterization of MEMS based inertial sensors and the performance of an integrated system prototype of MEMS based inertial sensors, a low-cost GPS receiver and a digital compass. The influence of the stochastic variation of sensors will be assessed and modeled by two different methods, namely Gauss-Markov (GM and AutoRegressive (AR models, with GPS signal blockage of different lengths. Numerical results from kinematic testing have been used to assess the performance of different modeling schemes.

  7. A Wireless MEMS-Based Inclinometer Sensor Node for Structural Health Monitoring

    Science.gov (United States)

    Ha, Dae Woong; Park, Hyo Seon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This paper proposes a wireless inclinometer sensor node for structural health monitoring (SHM) that can be applied to civil engineering and building structures subjected to various loadings. The inclinometer used in this study employs a method for calculating the tilt based on the difference between the static acceleration and the acceleration due to gravity, using a micro-electro-mechanical system (MEMS)-based accelerometer. A wireless sensor node was developed through which tilt measurement data are wirelessly transmitted to a monitoring server. This node consists of a slave node that uses a short-distance wireless communication system (RF 2.4 GHz) and a master node that uses a long-distance telecommunication system (code division multiple access—CDMA). The communication distance limitation, which is recognized as an important issue in wireless monitoring systems, has been resolved via these two wireless communication components. The reliability of the proposed wireless inclinometer sensor node was verified experimentally by comparing the values measured by the inclinometer and subsequently transferred to the monitoring server via wired and wireless transfer methods to permit a performance evaluation of the wireless communication sensor nodes. The experimental results indicated that the two systems (wired and wireless transfer systems) yielded almost identical values at a tilt angle greater than 1°, and a uniform difference was observed at a tilt angle less than 0.42° (approximately 0.0032° corresponding to 0.76% of the tilt angle, 0.42°) regardless of the tilt size. This result was deemed to be within the allowable range of measurement error in SHM. Thus, the wireless transfer system proposed in this study was experimentally verified for practical application in a structural health monitoring system. PMID:24287533

  8. Long-term neural recordings using MEMS based moveable microelectrodes in the brain

    Directory of Open Access Journals (Sweden)

    Nathan Jackson

    2010-06-01

    Full Text Available One of the critical requirements of the emerging class of neural prosthetic devices is to maintain good quality neural recordings over long time periods. We report here a novel (Micro-ElectroMechanical Systems based technology that can move microelectrodes in the event of deterioration in neural signal to sample a new set of neurons. Microscale electro-thermal actuators are used to controllably move microelectrodes post-implantation in steps of approximately 9 µm. In this study, a total of 12 moveable microelectrode chips were individually implanted in adult rats. Two of the 12 moveable microelectrode chips were not moved over a period of 3 weeks and were treated as control experiments. During the first three weeks of implantation, moving the microelectrodes led to an improvement in the average SNR from 14.61 ± 5.21 dB before movement to 18.13 ± 4.99 dB after movement across all microelectrodes and all days. However, the average RMS values of noise amplitudes were similar at 2.98 ± 1.22 µV and 3.01 ± 1.16 µV before and after microelectrode movement. Beyond three weeks, the primary observed failure mode was biological rejection of the PMMA (dental cement based skull mount resulting in the device loosening and eventually falling from the skull. Additionally, the average SNR for functioning devices beyond three weeks was 11.88 ± 2.02 dB before microelectrode movement and was significantly different (p<0.01 from the average SNR of 13.34 ± 0.919 dB after movement. The results of this study demonstrate that MEMS based technologies can move microelectrodes in rodent brains in long-term experiments resulting in improvements in signal quality. Further improvements in packaging and surgical techniques will potentially enable movable microelectrodes to record cortical neuronal activity in chronic experiments.

  9. Design of a MEMS-Based Oscillator Using 180nm CMOS Technology.

    Science.gov (United States)

    Roy, Sukanta; Ramiah, Harikrishnan; Reza, Ahmed Wasif; Lim, Chee Cheow; Ferrer, Eloi Marigo

    2016-01-01

    Micro-electro mechanical system (MEMS) based oscillators are revolutionizing the timing industry as a cost effective solution, enhanced with more features, superior performance and better reliability. The design of a sustaining amplifier was triggered primarily to replenish MEMS resonator's high motion losses due to the possibility of their 'system-on-chip' integrated circuit solution. The design of a sustaining amplifier observing high gain and adequate phase shift for an electrostatic clamp-clamp (C-C) beam MEMS resonator, involves the use of an 180nm CMOS process with an unloaded Q of 1000 in realizing a fixed frequency oscillator. A net 122dBΩ transimpedance gain with adequate phase shift has ensured 17.22MHz resonant frequency oscillation with a layout area consumption of 0.121 mm2 in the integrated chip solution, the sustaining amplifier draws 6.3mW with a respective phase noise of -84dBc/Hz at 1kHz offset is achieved within a noise floor of -103dBC/Hz. In this work, a comparison is drawn among similar design studies on the basis of a defined figure of merit (FOM). A low phase noise of 1kHz, high figure of merit and the smaller size of the chip has accredited to the design's applicability towards in the implementation of a clock generative integrated circuit. In addition to that, this complete silicon based MEMS oscillator in a monolithic solution has offered a cost effective solution for industrial or biomedical electronic applications.

  10. Design of a MEMS-Based Oscillator Using 180nm CMOS Technology.

    Directory of Open Access Journals (Sweden)

    Sukanta Roy

    Full Text Available Micro-electro mechanical system (MEMS based oscillators are revolutionizing the timing industry as a cost effective solution, enhanced with more features, superior performance and better reliability. The design of a sustaining amplifier was triggered primarily to replenish MEMS resonator's high motion losses due to the possibility of their 'system-on-chip' integrated circuit solution. The design of a sustaining amplifier observing high gain and adequate phase shift for an electrostatic clamp-clamp (C-C beam MEMS resonator, involves the use of an 180nm CMOS process with an unloaded Q of 1000 in realizing a fixed frequency oscillator. A net 122dBΩ transimpedance gain with adequate phase shift has ensured 17.22MHz resonant frequency oscillation with a layout area consumption of 0.121 mm2 in the integrated chip solution, the sustaining amplifier draws 6.3mW with a respective phase noise of -84dBc/Hz at 1kHz offset is achieved within a noise floor of -103dBC/Hz. In this work, a comparison is drawn among similar design studies on the basis of a defined figure of merit (FOM. A low phase noise of 1kHz, high figure of merit and the smaller size of the chip has accredited to the design's applicability towards in the implementation of a clock generative integrated circuit. In addition to that, this complete silicon based MEMS oscillator in a monolithic solution has offered a cost effective solution for industrial or biomedical electronic applications.

  11. Protect Against Exposure on Formaldehyde

    Science.gov (United States)

    Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.

  12. and phenol–formaldehyde resin

    Indian Academy of Sciences (India)

    formaldehyde resin (PFR) modified with tetraethylorthosilicate are investigated in detail. The chemical synthesis of PFR, its modification with nanometer- sized SiO2 particles created by sol–gel method and subsequent coating, enables a preparation of ...

  13. Absorption of formaldehyde in water

    NARCIS (Netherlands)

    Winkelman, Jozef Gerhardus Maria

    2003-01-01

    Deze dissertatie beschrijft theoretisch en experimenteel werk aan de absorptie van formaldehyde in water. Met resultaten hiervan zijn chemisch-technische modellen ontwikkeld voor de beschrijving en optimalisatie van industriële formaldehydeabsorbeurs. Deze samenvatting geeft eerst algemene

  14. Monitoring of formaldehyde in air.

    Science.gov (United States)

    Balmat, J L; Meadows, G W

    1985-10-01

    Any one of several monitoring methods, depending on requirement and circumstance, can be used to measure employee exposure to formaldehyde. Ordinarily, monitoring at DuPont is performed by sampling with impingers containing 1% aqueous sodium bisulfite or with silica gel tubes. The collected formaldehyde is measured spectrophotometrically after reaction with chromotropic acid. Results from studies on a selected number of formaldehyde monitoring methods reveal that reliable methods are available for area and personnel monitoring over both short term and long term. Accurate results are obtained from short-term monitoring (15 min at 1 L/min) with impingers of formaldehyde concentrations as low as 0.14 ppm. The current studies show that long-term monitoring (8 hr at 0.5 L/min) can be performed accurately at concentrations as low as 0.05 ppm. Accurate results also are obtained from short-term monitoring (15 min at 500 mL/min) with silica gel tubes of concentrations as low as 0.11 ppm formaldehyde; the lower limit established in the current studies for long-term monitoring (8 hr at 30 mL/min) is 0.15 ppm. Passive monitors provide the most convenient means of obtaining 8-hour time-weighted average (TWA) data. The Pro-Tek Formaldehyde Badge was demonstrated to reliably monitor formaldehyde concentrations varying from 0-0.5 ppm or 0-3 ppm. All of these methods satisfy the NIOSH criterion for acceptability that all results fall within +/- 25% of the true value at the 95% confidence level. Investigation of the Lion Formaldemeter disclosed that instantaneous and accurate (+/- 5%) measurement of formaldehyde in air can be made over a concentration range of 0.3-5 ppm in the absence of other substances that are oxidizable in its fuel cell detector.

  15. Removal of formaldehyde by adsorption and plasma treatment of mineral adsorbent

    Science.gov (United States)

    Saulich, K.; Müller, S.

    2013-01-01

    Formaldehyde is a harmful ambient air pollutant which can be produced by incomplete combustion processes, e.g. in power plants or automobiles. In this work a cycled adsorption and discharge process using mineral granulate in a packed bed dielectric barrier discharge plasma reactor was applied for formaldehyde (99 ppm) removal from gas streams. The mineral granulate used consisted of 80% halloysite and showed a good adsorption capacity for formaldehyde. In the discharge step, the adsorbed formaldehyde molecules were decomposed to COx and hydrocarbons in a N2 plasma at a low input discharge power of 2.2 W. The decomposition performance on adsorbed formaldehyde molecules was studied depending on space-time, a specific oxygen fraction of the carrier gas and the influence of temperature. With rising N2 space times in the discharge area, the total amount of decomposed formaldehyde molecules increased and the decomposition reaction mechanism shifted to CO2 formation. An oxygen fraction in the carrier gas further raised the oxidized amount of formaldehyde to CO2. The mineral granulate showed satisfied regeneration ability during the cycled plasma process.

  16. Development of Formaldehyde Adsorption using Modified Activated Carbon – A Review

    Directory of Open Access Journals (Sweden)

    W.D.P Rengga

    2012-11-01

    Full Text Available Gas storage is a technology developed with an adsorptive storage method, in which gases are stored as adsorbed components on the certain adsorbent. Formaldehyde is one of the major indoor gaseous pollutants. Depending on its concentration, formaldehyde may cause minor disorder symptoms to a serious injury. Some of the successful applications of technology for the removal of formaldehyde have been reported. However, this paper presents an overview of several studies on the elimination of formaldehyde that has been done by adsorption method because of its simplicity. The adsorption method does not require high energy and the adsorbent used can be obtained from inexpensive materials. Most researchers used activated carbon as an adsorbent for removal of formaldehyde because of its high adsorption capacity. Activated carbons can be produced from many materials such as coals, woods, or agricultural waste. Some of them were prepared by specific activation methods to improve the surface area. Some researchers also used modified activated carbon by adding specific additive to improve its performance in attracting formaldehyde molecules. Proposed modification methods on activation and additive impregnated carbon are thus discussed in this paper for future development and improvement of formaldehyde adsorption on activated carbon. Specifically, a waste agricultural product is chosen for activated carbon raw material because it is renewable and gives an added value to the materials. The study indicates that the performance of the adsorption of formaldehyde might be improved by using modified activated carbon. Bamboo seems to be the most appropriate raw materials to produce activated carbon combined with applying chemical activation method and addition of metal oxidative catalysts such as Cu or Ag in nano size particles. Bamboo activated carbon can be developed in addition to the capture of formaldehyde as well as the storage of adsorptive hydrogen gas that

  17. Formaldehyde concentrations in household air of asthma patients determined using colorimetric detector tubes

    Science.gov (United States)

    Dannemiller, Karen C.; Murphy, Johnna S.; Dixon, Sherry L.; Pennell, Kelly G.; Suuberg, Eric M.; Jacobs, David E.; Sandel, Megan

    2013-01-01

    Formaldehyde is a colorless, pungent gas commonly found in homes that is a respiratory irritant, sensitizer, carcinogen and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-minute grab samples in length-of-stain detector tubes in homes (n=70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5–132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics (pformaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children (p=0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma. PMID:23278296

  18. Formaldehyde stress responses in bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Nathan Houqian Chen

    2016-03-01

    Full Text Available Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed.

  19. Formaldehyde - An Assessment of its Health Effects.

    Science.gov (United States)

    1980-03-01

    formaldehyde mutagenesis has not been resolved. Formaldehyde may cause mutations by reacting directly with DNA ; by forming mutagenic products on...reaction with amino groups on simple amines, amino acids, nucleic acids, or proteins; or by oxidizing to peroxides that can react directly with DNA or...species of grasshoppers , formaldehyde caused chromosomal damage (Manna and Parida, 1967). Germinating barley seeds soaked in formaldehyde solutions did not

  20. Formaldehyde preparation methods for pressure and temperature dependent laser-induced fluorescence measurements

    Science.gov (United States)

    Burkert, A.; Müller, D.; Rieger, S.; Schmidl, G.; Triebel, W.; Paa, W.

    2015-12-01

    Formaldehyde is an excellent tracer for the early phase of ignition of hydrocarbon fuels and can be used, e.g., for characterization of single droplet ignition. However, due to its fast thermal decomposition at elevated temperatures and pressures, the determination of concentration fields from laser-induced fluorescence (LIF) measurements is difficult. In this paper, we address LIF measurements of this important combustion intermediate using a calibration cell. Here, formaldehyde is created from evaporation of paraformaldehyde. We discuss three setups for preparation of formaldehyde/air mixtures with respect to their usability for well-defined heating of formaldehyde/air mixtures. The "basic setup" uses a resist heater around the measurement cell for investigation of formaldehyde near vacuum conditions or formaldehyde/air samples after sequential admixing of air. The second setup, described for the first time in detail here, takes advantage of a constant flow formaldehyde/air regime which uses preheated air to reduce the necessary time for gas heating. We used the constant flow system to measure new pressure dependent LIF excitation spectra in the 343 nm spectral region (414 absorption band of formaldehyde). The third setup, based on a novel concept for fast gas heating via excitation of SF6 (chemically inert gas) using a TEA (transverse excitation at atmospheric pressure) CO2 laser, allows to further minimize both gas heating time and thermal decomposition. Here, an admixture of CO2 is served for real time temperature measurement based on Raman scattering. The applicability of the fast laser heating system has been demonstrated with gas mixtures of SF6 + air, SF6 + N2, as well as SF6 + N2 + CO2 at 1 bar total pressure.

  1. Urban MEMS based seismic network for post-earthquakes rapid disaster assessment

    Science.gov (United States)

    D'Alessandro, Antonino; Luzio, Dario; D'Anna, Giuseppe

    2014-05-01

    worship. The waveforms recorded could be promptly used to determine ground-shaking parameters, like peak ground acceleration/velocity/displacement, Arias and Housner intensity, that could be all used to create, few seconds after a strong earthquakes, shaking maps at urban scale. These shaking maps could allow to quickly identify areas of the town center that have had the greatest earthquake resentment. When a strong seismic event occur, the beginning of the ground motion observed at the site could be used to predict the ensuing ground motion at the same site and so to realize a short term earthquake early warning system. The data acquired after a moderate magnitude earthquake, would provide valuable information for the detail seismic microzonation of the area based on direct earthquake shaking observations rather than from a model-based or indirect methods. In this work, we evaluate the feasibility and effectiveness of such seismic network taking in to account both technological, scientific and economic issues. For this purpose, we have simulated the creation of a MEMS based urban seismic network in a medium size city. For the selected town, taking into account the instrumental specifics, the array geometry and the environmental noise, we investigated the ability of the planned network to detect and measure earthquakes of different magnitude generated from realistic near seismogentic sources.

  2. Quantitative determination of formaldehyde by spectrophotometry ...

    African Journals Online (AJOL)

    Formaldehyde is a vastly used material in industry. Nowadays, it is proven that formaldehyde is toxic and carcinogenic. Thus providing a reliable method for its quantitative determination is very important. This study proposes a UV-Vis spectrophotometric based method for determination of formaldehyde. The method is ...

  3. Effect of urea formaldehyde viscosity on urea formaldehyde and ...

    African Journals Online (AJOL)

    The melting point, refractive index, density and formaldehyde emission were found to increase with increase in UF viscosity while the dry time, moisture uptake and elongation at break were found to decrease with increase in viscosity. UF viscosity below 10.82 mPa.s was found to produce UF/UP copolymer composite which ...

  4. Formaldehyde in cosmetics in patch tested dermatitis patients with and without contact allergy to formaldehyde.

    Science.gov (United States)

    Hauksson, Inese; Pontén, Ann; Isaksson, Marléne; Hamada, Haneen; Engfeldt, Malin; Bruze, Magnus

    2016-03-01

    Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in cosmetics. To survey the release of formaldehyde in cosmetics brought by patients investigated because of suspected allergic contact dermatitis, to compare it with information given by the manufacturers on the packages, and to investigate whether formaldehyde-allergic patients are potentially exposed to more cosmetics releasing formaldehyde than dermatitis patients without contact allergy to formaldehyde. Cosmetics from 10 formaldehyde-allergic and 30 non-allergic patients (controls) matched for age and sex were investigated with the chromotropic acid spot test, which is a semiquantitative method measuring the release of formaldehyde. Formaldehyde was found in 58 of 245 (23.7%) products. Twenty-six of 126 (20.6%) leave-on products released formaldehyde, and 17 of 26 (65.4%) of these were not declared to contain formaldehyde or formaldehyde releasers. Among the rinse-off products, there were 32 of 119 (26.8%) formaldehyde-releasing products, and nine of 32 (28.0%) of these were not labelled as containing formaldehyde or formaldehyde releasers. Five of 10 formaldehyde-allergic patients brought leave-on products with ≥ 40 ppm formaldehyde, as compared with 4 of 30 in the control group (p = 0.029). Cosmetic products used by formaldehyde-allergic patients that are not declared to contain formaldehyde or formaldehyde-releasing preservatives should be analysed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Formaldehyde monitor for automobile exhausts

    Science.gov (United States)

    Easley, W. C.

    1973-01-01

    Device makes use of microwave spectral absorption in low-Q resonant Stark cell, and indications are that ultimate sensitivity of instrument is within 100 parts per billion of formaldehyde. Microwave source is very small and requires only six-volt dc bias for operation. Coarse tuning is accomplished mechanically and fine tuning by adjusting dc-bias voltage.

  6. Induction of formaldehyde contact sensitivity

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Boman, A; Vølund, A

    1985-01-01

    , and formaldehyde 1% and 0.1% was used for challenge. The incidence of contact sensitivity depended on the intradermal, but not on the topical induction dose. Statistical analyses showed a non-monotonous (non-linear) dose response relationship. The estimated maximal sensitization rate in Copenhagen was 80% after...

  7. Nanocomposite sensors of propylene glycol, dimethylformamide and formaldehyde vapors

    Directory of Open Access Journals (Sweden)

    Z. Adamyan

    2018-02-01

    Full Text Available The results of research works related to the study of thick-film multiwall carbon nanotube–tin oxide nanocomposite sensors of propylene glycol (PG, dimethylformamide (DMF and formaldehyde (FA vapors are presented in this paper. These sensors were derived using hydrothermal synthesis and sol–gel methods. Investigations of response–recovery characteristics in the 50–300 °C operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times are about 200 and 220 °C, respectively. The dependence of the sensor response on gas concentration is linear in all cases. Minimal propylene glycol, dimethylformamide and formaldehyde gas concentrations, where the perceptible signal was noticed, were 13, 5 and 115 ppm, respectively.

  8. Film bulk acoustic formaldehyde sensor with layer-by-layer assembled carbon nanotubes/polyethyleneimine multilayers

    Science.gov (United States)

    Wang, Wei; Chen, Da; Wang, Hongfei; Yu, Wenhua; Wu, Maozeng; Yang, Lei

    2018-02-01

    Trace formaldehyde vapor was detected by a micron-scale AlN film bulk acoustic resonator based on mass-sensitive mechanism. The layer-by-layer carbon nanotubes/polyethyleneimine multilayers were assembled on the resonator surface as the sensitive coating. An almost linear decrease of the resonant frequency was observed as a function of the number of nanotubes/polyethyleneimine periods. The multilayers showed a random and porous structure and thus provided a large specific surface area for gas adsorption and diffusion. At the same time, the amine groups in polyethyleneimine had an strong affinity to formaldehyde with excellent selectivity. When exposed to gaseous formaldehyde, the attachment of gas molecules induced a small decrease in the resonant frequency, which made the sensor easily detect formaldehyde at ppb levels with 1 min response time. A linear relationship was observed between the formaldehyde concentrations and the frequency downshift of the resonator. The layer number had an obvious influence on the absorption/desorption behavior of formaldehyde. The gas sensitivity of FBAR sensors was 1.29–1.90 kHz ppb‑1 with the limit of detection of 24–38 ppb.

  9. The methods of formaldehyde emission testing of engine: A review

    Science.gov (United States)

    Zhang, Chunhui; Geng, Peng; Cao, Erming; Wei, Lijiang

    2015-12-01

    A number of measurements have been provided to detect formaldehyde in the atmosphere, but there are no clear unified standards in engine exhaust. Nowadays, formaldehyde, an unregulated emission from methanol engine, has been attracting increasing attention by researchers. This paper presents the detection techniques for formaldehyde emitted from the engines applied in recent market, introducing the approaches in terms of unregulated emission tests of formaldehyde, which involved gas chromatography, liquid chromatography, chromatography-mass spectrometry, chromatography-spectrum, Fourier infrared spectroscopy and spectrophotometry. The author also introduces the comparison regarding to the advantages of the existing detection techniques based on the principle, to compare with engine exhaust sampling method, the treatment in advance of detection, obtaining approaches accessing to the qualitative and quantitative analysis of chromatograms or spectra. The accuratest result obtained was chromatography though it cannot be used continuously. It also can be utilized to develop high requirements of emissions and other regulations. Fourier infrared spectroscopy has the advantage of continuous detection for a variety of unregulated emissions and can be applied to the bench in variable condition. However, its accuracy is not as good as chromatography. As the conclusion, a detection technique is chosen based on different requirements.

  10. A novel derivatization-free method of formaldehyde and propylene glycol determination in hydrogels by liquid chromatography with refractometric detection.

    Science.gov (United States)

    Isakau, Henadz; Robert, Marielle; Shingel, Kirill I

    2009-04-05

    The paper describes the development and validation of a new derivatization-free liquid chromatography method for simultaneous determination of propylene glycol and formaldehyde in the formulations containing formaldehyde-releasing preservative. Highly swollen hydrogel made of poly(ethylene glycol)-protein conjugates was taken as a model formulation for integration of the propylene glycol and the diazolydinyl urea as formaldehyde releaser. The method is shown to be simple and selective and, more importantly, allows determining an existing level of formaldehyde at the moment of analysis instead of all available formaldehyde that might be released during chemical derivatization. After liquid extraction the propylene glycol (PG) and formaldehyde (FA) amounts are determined chromatographically on a Shodex SH 1011 ligand-exchange column using 0.01 M sulfuric acid mobile phase, a flow rate of 1.0 ml/min and RI detection. The assay is validated showing good linearity, precision, and accuracy. The limits of detection of formaldehyde and propylene glycol in the analyzed solutions were estimated to be 25 ng and 87 ng, respectively. This analytical assay is considered useful for product stability studies and in developing new formaldehyde releaser-containing formulations where the concentration of formaldehyde is a presumable subject of labeling requirements. This method can also provide a rapid and convenient alternative to gas chromatography method of propylene glycol quantification.

  11. Micro-electro-mechanical-system (MEMS)-based fiber optic grating sensor for improving weapon stabilization and fire control

    Science.gov (United States)

    Zhang, Sean Z.; Xu, Guoda; Qui, Wei; Lin, Freddie S.; Testa, Robert C.; Mattice, Michael S.

    2000-06-01

    A MEMS-based fiber optic grating sensor (FOGS) for improving weapon stabilization and fire control has been investigated and developed. The technique overwrites two fiber Bragg gratings (FBGs) onto a polarization-preserving optical fiber core. A MEMS diaphragm is fabricated and integrated with the overlaid FBGs to enhance the performance and reliability of the sensor. A simulation model for the MEMS-FOGS was derived, and simulation results concerning load, angle, strain, and temperature were obtained. The fabricated MEMS diaphragm and the overlaid FBGs are packaged together and mounted on a specially designed cantilever beam system. User-friendly software for sensing system design and data analysis has been developed and can be used to control other sensing systems. The combined multifunctional sensitive. The fully developed sensing system is expected to find applications in fire control, weapon stabilization, and other areas where accurately sensing strain and temperature is critical.

  12. Homogeneity analysis of high yield manufacturing process of mems-based pzt thick film vibrational energy harvesters

    DEFF Research Database (Denmark)

    Lei, Anders; Xu, Ruichao; Pedersen, C.M.

    2011-01-01

    This work presents a high yield wafer scale fabrication of MEMS-based unimorph silicon/PZT thick film vibrational energy harvesters aimed towards vibration sources with peak frequencies in the range of a few hundred Hz. By combining KOH etching with mechanical front side protection, SOI wafer...... to accurately define the thickness of the silicon part of the harvester and a silicon compatible PZT thick film screen-printing technique, we are able to fabricate energy harvesters on wafer scale with a yield higher than 90%. The characterization of the fabricated harvesters is focused towards the full wafer....../mass-production aspect; hence the analysis of uniformity in harvested power and resonant frequency....

  13. MEMS-based Optic Fiber Fabry-Perot Sensor for Underwater Acoustic Measurement with A Wavelength-switched System

    Science.gov (United States)

    Xia, J.; Y Wang, F.; Luo, H.; Hu, Y. M.; Xiong, S. D.

    2017-12-01

    In this paper, a MEMS-based extrinsic Farby-Perot Interferometric (EFPI) acoustic pressure acoustic sensor is presented. The diaphragm structure is used as the second reflected surface, and the sensitive surface to acoustic pressure. A wavelength-switched phase demodulation system for EFPI sensors is used for acoustic signal recovery. The modified phase demodulation system has been demonstrated to recover the signal to a stable intensity fluctuation level of ±0.5 dB at the test frequency of 2000 Hz. In the test depth of 50cm, the sensor has a resonant frequency of 3.7 kHz, a flat frequency range of 10-800Hz, and a corresponding acoustic pressure sensitivity of -159 dB re. 1/μPa.

  14. MEMS-BASED 3D CONFOCAL SCANNING MICROENDOSCOPE USING MEMS SCANNERS FOR BOTH LATERAL AND AXIAL SCAN.

    Science.gov (United States)

    Liu, Lin; Wang, Erkang; Zhang, Xiaoyang; Liang, Wenxuan; Li, Xingde; Xie, Huikai

    2014-08-15

    A fiber-optic 3D confocal scanning microendoscope employing MEMS scanners for both lateral and axial scan was designed and constructed. The MEMS 3D scan engine achieved a lateral scan range of over ± 26° with a 2D MEMS scanning micromirror and a depth scan of over 400 μm with a 1D MEMS tunable microlens. The lateral resolution and axial resolution of this system were experimentally measured as 1.0 μm and 7.0 μm, respectively. 2D and 3D confocal reflectance images of micro-patterns, micro-particles, onion skins and acute rat brain tissue were obtained by this MEMS-based 3D confocal scanning microendoscope.

  15. Formaldehyde and acetaldehyde emissions from residential wood combustion in Portugal

    Science.gov (United States)

    Cerqueira, Mário; Gomes, Luís; Tarelho, Luís; Pio, Casimiro

    2013-06-01

    A series of experiments were conducted to characterize formaldehyde and acetaldehyde emissions from residential combustion of common wood species growing in Portugal. Five types of wood were investigated: maritime pine (Pinus pinaster), eucalyptus (Eucalyptus globulus), cork oak (Quercus suber), holm oak (Quercus rotundifolia) and pyrenean oak (Quercus pyrenaica). Laboratory experiments were performed with a typical wood stove used for domestic heating in Portugal and operating under realistic home conditions. Aldehydes were sampled from diluted combustion flue gas using silica cartridges coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with diode array detection. The average formaldehyde to acetaldehyde concentration ratio (molar basis) in the stove flue gas was in the range of 2.1-2.9. Among the tested wood types, pyrenean oak produced the highest emissions for both formaldehyde and acetaldehyde: 1772 ± 649 and 1110 ± 454 mg kg-1 biomass burned (dry basis), respectively. By contrast, maritime pine produced the lowest emissions: 653 ± 151 and 371 ± 162 mg kg-1 biomass (dry basis) burned, respectively. Aldehydes were sampled separately during distinct periods of the holm oak wood combustion cycles. Significant variations in the flue gas concentrations were found, with higher values measured during the devolatilization stage than in the flaming and smoldering stages.

  16. A new airborne formaldehyde instrument: Compact Formaldehyde Fluorescence Experiment (COFFEE)

    Science.gov (United States)

    Hanisco, T. F.; Bailey, S. A.; Swanson, A. K.; Wolfe, G. M., Jr.

    2014-12-01

    We present the operating principles of a new instrument designed for operation on small aircraft. The instrument uses a new non-resonant fluorescence technique to take advantage of compact industrial lasers to make a small, robust package that can measure formaldehyde at sensitivities better than 100 ppt in 1 second integration. The instrument is designed to fly on the Alphajet at NASA Ames but can be modified to fly on other small aircraft.

  17. On-line monitoring of methanol and methyl formate in the exhaust gas of an industrial formaldehyde production plant by a mid-IR gas sensor based on tunable Fabry-Pérot filter technology.

    Science.gov (United States)

    Genner, Andreas; Gasser, Christoph; Moser, Harald; Ofner, Johannes; Schreiber, Josef; Lendl, Bernhard

    2017-01-01

    On-line monitoring of key chemicals in an industrial production plant ensures economic operation, guarantees the desired product quality, and provides additional in-depth information on the involved chemical processes. For that purpose, rapid, rugged, and flexible measurement systems at reasonable cost are required. Here, we present the application of a flexible mid-IR filtometer for industrial gas sensing. The developed prototype consists of a modulated thermal infrared source, a temperature-controlled gas cell for absorption measurement and an integrated device consisting of a Fabry-Pérot interferometer and a pyroelectric mid-IR detector. The prototype was calibrated in the research laboratory at TU Wien for measuring methanol and methyl formate in the concentration ranges from 660 to 4390 and 747 to 4610 ppmV. Subsequently, the prototype was transferred and installed at the project partner Metadynea Austria GmbH and linked to their Process Control System via a dedicated micro-controller and used for on-line monitoring of the process off-gas. Up to five process streams were sequentially monitored in a fully automated manner. The obtained readings for methanol and methyl formate concentrations provided useful information on the efficiency and correct functioning of the process plant. Of special interest for industry is the now added capability to monitor the start-up phase and process irregularities with high time resolution (5 s).

  18. ALLERGIC CONTACT DERMATITIS FROM FORMALDEHYDE EXPOSURE.

    Directory of Open Access Journals (Sweden)

    Maya Lyapina

    2012-10-01

    Full Text Available Formaldehyde is a ubiquitous chemical agent, a part of our outdoor and indoor working and residential environment. Healthcare workers in difficult occupations are among the most affected by formaldehyde exposure. Formaldehyde is an ingredient of some dental materials. Formaldehyde is well-known mucous membrane irritant and a primary skin sensitizing agent associated with both contact dermatitis (Type IV allergy, and immediate, anaphylactic reactions (Type I allergy. Inhalation exposure to formaldehyde was identified as a potential cause of asthma. Quite a few investigations are available concerning health issues for dental students following formaldehyde exposure. Such studies would be beneficial for early diagnosis of hypersensitivity, adequate prophylactic, risk assessment and management of their work.

  19. 78 FR 51696 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-08-21

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ44 Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products; Extension of Comment Period AGENCY: Environmental... formaldehyde standards for composite wood products. After receiving requests for an extension, EPA extended the...

  20. 78 FR 44090 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Science.gov (United States)

    2013-07-23

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ44 Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite Wood Products; Extension of Comment Period AGENCY: Environmental... formaldehyde standards for composite wood products. This document extends the comment period from August 9...

  1. Initial inventory of alternatives to biocidal products containing formaldehyde of formaldehyde releasers

    NARCIS (Netherlands)

    Wezenbeek JM; Janssen MPM; Scheepmaker JWA; MSP; M&V

    2015-01-01

    Formaldehyde is de werkzame stof in veel desinfecteer- en conserveringsmiddelen, maar deze stof is kankerverwekkend. Daarom zal formaldehyde naar verwachting per 1 januari 2016 op Europees niveau als zodanig worden geclassificeerd (carcinogeen 1B). Dit kan betekenen dat formaldehyde-houdende

  2. MEMS-based Porous Silicon Preconcentrators Filled with Carbopack-B for Explosives Detection

    OpenAIRE

    Camara , El Hadji Malik; James , Franck; Breuil , Philippe; Pijolat , Christophe; Briand , Danick; De Rooij , Nicolaas F

    2014-01-01

    International audience; In this paper we report the detection of explosive compounds using a miniaturized gas preconcentrator (μGP) made of porous silicon (PS) filled in with Carbopack B as an adsorbent material. The μGP includes also a platinum heater patterned at the backside and fluidic connectors sealed on the glass cover. Our μGP is designed and optimized through fluidic and thermal simulations for meeting the requirements of trace explosives detection. The thermal mass of the device was...

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

    Science.gov (United States)

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

    2012-01-01

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

  4. short communication quantitative determination of formaldehyde

    African Journals Online (AJOL)

    Preferred Customer

    ALS). Data processing by this chemometrics technique enhanced the reliability of the UV-Vis spectrophotometry for quantitative analysis of formaldehyde in real samples. KEY WORDS: Formaldehyde, Fluoral P, UV-Visible, Multivariate curve resolution alternating least squares;. Quantitative analysis. INTRODUCTION.

  5. 29 CFR 1915.1048 - Formaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical to...

  6. 29 CFR 1926.1148 - Formaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148 Formaldehyde...

  7. Formaldehyde concentration in diagnostic patch testing

    DEFF Research Database (Denmark)

    Trattner, A; Johansen, J D; Menné, T

    1998-01-01

    Exposure to formaldehyde is common from both consumer products and industry. The reliability of the patch test is essential for the diagnosis of formaldehyde allergy as it is difficult to suspect from the patient's history. The recommended formaldehyde patch test concentration has been reduced over......% in consecutively patch-tested patients, with respect to frequency of positive patch test reactions, strength of patch test reactions to different formaldehyde test concentrations, irritancy and relevance. The study included 3734 consecutively patch tested patients. 121 gave a positive reaction to 1% and/or 2...... gave few additional positive cases compared to D 3/4. Problems related to relevance are discussed. Based on present knowledge, a 1% patch test concentration for formaldehyde is recommended....

  8. Denaturation and electrophoresis of RNA with formaldehyde.

    Science.gov (United States)

    Rio, Donald C

    2015-02-02

    Electrophoretic size fractionation can be used to denature and separate large mRNA molecules (0.5-10 kb) on formaldehyde-containing agarose gels. Formaldehyde contains a carbonyl group that reacts to form Schiff bases with the imino or amino groups of guanine, adenine, and cytosine. These covalent adducts prevent normal base pairing and maintain the RNA in a denatured state. Because these adducts are unstable, formaldehyde must be present in the gel to maintain the RNA in the denatured state. This protocol describes the preparation of an agarose gel with formaldehyde and its setup in a horizontal electrophoresis apparatus. RNA samples are prepared and denatured in a solution of formamide and formaldehyde and, with 0.5- to 10-kb size markers, subjected to electrophoresis through the gel. Following electrophoresis, the gel is stained to visualize RNA markers or rRNA using one of several different types of stains. © 2015 Cold Spring Harbor Laboratory Press.

  9. A digital output accelerometer using MEMS-based piezoelectric accelerometers and arrayed CMOS inverters with satellite capacitors

    International Nuclear Information System (INIS)

    Kobayashi, T; Okada, H; Maeda, R; Itoh, T; Masuda, T

    2011-01-01

    The present paper describes the development of a digital output accelerometer composed of microelectromechanical systems (MEMS)-based piezoelectric accelerometers and arrayed complementary metal–oxide–semiconductor (CMOS) inverters accompanied by capacitors. The piezoelectric accelerometers were fabricated from multilayers of Pt/Ti/PZT/Pt/Ti/SiO 2 deposited on silicon-on-insulator (SOI) wafers. The fabricated piezoelectric accelerometers were connected to arrayed CMOS inverters. Each of the CMOS inverters was accompanied by a capacitor with a different capacitance called a 'satellite capacitor'. We have confirmed that the output voltage generated from the piezoelectric accelerometers can vary the output of the CMOS inverters from a high to a low level; the state of the CMOS inverters has turned from the 'off-state' into the 'on-state' when the output voltage of the piezoelectric accelerometers is larger than the threshold voltage of the CMOS inverters. We have also confirmed that the CMOS inverters accompanied by the larger satellite capacitor have become 'on-state' at a lower acceleration. On increasing the acceleration, the number of on-state CMOS inverters has increased. Assuming that the on-state and off-state of CMOS inverters correspond to logic '0' and '1', the present digital output accelerometers have expressed the accelerations of 2.0, 3.0, 5.0, and 5.5 m s −2 as digital outputs of 111, 110, 100, and 000, respectively

  10. Assembly and performance testing of a MEMS-based {mu}PEMFC with the help of a spiral micrometer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xigui; Zhang, Jian; Li, Xinxin; Xia, Baojia [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Wang, Tao [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Space Power-Sources, Shanghai 200381 (China); Zheng, Dan [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Technology, Shanghai 200233 (China)

    2008-12-15

    In this work, a feasible and simple method of assembling a micro MEMS-based {mu}PEMFC (about 0.35 ml in volume and 0.65 g in weight) with the help of a spiral micrometer was proposed. The micrometer provided a constant pressure between the two flow field plates and MEA in assembling for a short term while a special epoxy resin was applied to seal the cell and provide long term pressure between the above components after removing the micrometer. Tests showed that the as-assembled cell had a reasonable performance, which was proved by the linear polarization and EIS experiments. The long term behavior of the {mu}PEMFC was stable in general except for some fluctuation along time. We concluded that this fluctuation was due to a combined effect of heat produced and water management, which the as-assembled {mu}PEMFC has its own ability to adjust. More importantly, this experiment demonstrated the full feasibility and great promise of assembling {mu}FCs with the help of a spiral micrometer. (author)

  11. Assembly and performance testing of a MEMS-based {mu}PEMFC with the help of a spiral micrometer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xigui [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China)], E-mail: zhangxigui@mail.sim.ac.cn; Zhang Jian [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Wang Tao [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Space Power-Sources, Shanghai 200381 (China); Zheng Dan [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China); Shanghai Institute of Technology, Shanghai 200233 (China); Li Xinxin; Xia Baojia [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Room 807, 8th Building, 865 Changning Road, Shanghai 200050 (China)

    2008-12-15

    In this work, a feasible and simple method of assembling a micro MEMS-based {mu}PEMFC (about 0.35 ml in volume and 0.65 g in weight) with the help of a spiral micrometer was proposed. The micrometer provided a constant pressure between the two flow field plates and MEA in assembling for a short term while a special epoxy resin was applied to seal the cell and provide long term pressure between the above components after removing the micrometer. Tests showed that the as-assembled cell had a reasonable performance, which was proved by the linear polarization and EIS experiments. The long term behavior of the {mu}PEMFC was stable in general except for some fluctuation along time. We concluded that this fluctuation was due to a combined effect of heat produced and water management, which the as-assembled {mu}PEMFC has its own ability to adjust. More importantly, this experiment demonstrated the full feasibility and great promise of assembling {mu}FCs with the help of a spiral micrometer.

  12. A Robust MEMS Based Multi-Component Sensor for 3D Borehole Seismic Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Paulsson Geophysical Services

    2008-03-31

    The objective of this project was to develop, prototype and test a robust multi-component sensor that combines both Fiber Optic and MEMS technology for use in a borehole seismic array. The use such FOMEMS based sensors allows a dramatic increase in the number of sensors that can be deployed simultaneously in a borehole seismic array. Therefore, denser sampling of the seismic wave field can be afforded, which in turn allows us to efficiently and adequately sample P-wave as well as S-wave for high-resolution imaging purposes. Design, packaging and integration of the multi-component sensors and deployment system will target maximum operating temperature of 350-400 F and a maximum pressure of 15000-25000 psi, thus allowing operation under conditions encountered in deep gas reservoirs. This project aimed at using existing pieces of deployment technology as well as MEMS and fiber-optic technology. A sensor design and analysis study has been carried out and a laboratory prototype of an interrogator for a robust borehole seismic array system has been assembled and validated.

  13. Regulation characteristics of oxide generation and formaldehyde removal by using volume DBD reactor

    Science.gov (United States)

    Bingyan, CHEN; Xiangxiang, GAO; Ke, CHEN; Changyu, LIU; Qinshu, LI; Wei, SU; Yongfeng, JIANG; Xiang, HE; Changping, ZHU; Juntao, FEI

    2018-02-01

    Discharge plasmas in air can be accompanied by ultraviolet (UV) radiation and electron impact, which can produce large numbers of reactive species such as hydroxyl radical (OH·), oxygen radical (O·), ozone (O3), and nitrogen oxides (NO x ), etc. The composition and dosage of reactive species usually play an important role in the case of volatile organic compounds (VOCs) treatment with the discharge plasmas. In this paper, we propose a volume discharge setup used to purify formaldehyde in air, which is configured by a plate-to-plate dielectric barrier discharge (DBD) channel and excited by an AC high voltage source. The results show that the relative spectral-intensity from DBD cell without formaldehyde is stronger than the case with formaldehyde. The energy efficiency ratios (EERs) of both oxides yield and formaldehyde removal can be regulated by the gas flow velocity in DBD channel, and the most desirable processing effect is the gas flow velocity within the range from 2.50 to 3.33 m s‑1. Moreover, the EERs of both the generated dosages of oxides (O3 and NO2) and the amount of removed formaldehyde can also be regulated by both of the applied voltage and power density loaded on the DBD cell. Additionally, the EERs of both oxides generation and formaldehyde removal present as a function of normal distribution with increasing the applied power density, and the peak of the function is appeared in the range from 273.5 to 400.0 W l‑1. This work clearly demonstrates the regulation characteristic of both the formaldehyde removal and oxides yield by using volume DBD, and it is helpful in the applications of VOCs removal by using discharge plasma.

  14. The detection of formaldehyde using microelectromechanical acoustic resonator with multiwalled carbon nanotubes-polyethyleneimine composite coating

    Science.gov (United States)

    Wang, Jingjing; Zhan, Da; Wang, Ke; Hang, Weiwei

    2018-01-01

    A micro-scale gas sensor based on mass-sensitive film bulk acoustic resonator is demonstrated for the detection of trace formaldehyde at room temperature. The composites mixed with multiwalled carbon nanotubes and polyethyleneimine (MWNTs-PEI) were coated on the resonator surface as the sensitive layer to specifically absorb formaldehyde molecules using a facile spray process. The influence of spraying processes on the formaldehyde sensing properties were investigated. Different response behaviors were determined by both the chemical absorption between formaldehyde molecules and the amine functional groups on PEI and the increase of absorption surface came from the nanostructure. The combination of high frequency of the film bulk acoustic resonator (~4.3 GHz) and the specific absorbability of MWNTs-PEI composites provided a high sensitivity in the detections of trace formaldehyde. The obtained ultra-low limit of detection was as low as 60 ppb with linear response, quick response/recovery time, good reproducibility and selectivity. The proposed sensor shows potential as a portable and convenient gas-sensing system for monitoring the low-level concentration of indoor air pollution.

  15. The Effect of Formaldehyde Fixation on RNA

    Science.gov (United States)

    Evers, David L.; Fowler, Carol B.; Cunningham, Brady R.; Mason, Jeffrey T.; O'Leary, Timothy J.

    2011-01-01

    Formalin-fixed, paraffin-embedded tissues generally provide low yields of extractable RNA that exhibit both covalent modification of nucleic acid bases and strand cleavage. This frustrates efforts to perform retrospective analyses of gene expression using archival tissue specimens. A variety of conditions have been reported to demodify formaldehyde-fixed RNA in different model systems. We studied the reversal of formaldehyde fixation of RNA using a 50 base RNA oligonucleotide and total cellular RNA. Formaldehyde-adducted, native, and hydrolyzed RNA species were identified by their bioanalyzer electrophoretic migration patterns and RT–quantitative PCR. Demodification conditions included temperature, time, buffer, and pH. The reversal of formaldehyde-fixed RNA to native species without apparent RNA hydrolysis was most successfully performed in dilute Tris, phosphate, or similar buffers (pH 8) at 70°C for 30 minutes. Amines were not required for efficient formaldehyde demodification. Formaldehyde-fixed RNA was more labile than native RNA to treatment with heat and buffer, suggesting that antigen retrieval methods for proteins may impede RNA hybridization or RNA extraction. Taken together, the data indicate that reliable conditions may be used to remove formaldehyde adducts from RNA to improve the quality of RNA available for molecular studies. PMID:21497290

  16. Effects of free formaldehyde emission reduction by ammonia fuming ...

    African Journals Online (AJOL)

    Particleboards made using formaldehyde adhesives cause substantial emission of free formaldehyde over time. Free formaldehyde is harmful to the user's health and it also weakens internal bonds of particleboards in use. Emissions levels of formaldehyde lie between 0.8 to 2.2 g/m3 of indoor air in particleboards ...

  17. Development of Unified Fabrication Process and Testing of MEMS Based Comb and Crab Type Capacitive Accelerometers for Navigational Applications

    Directory of Open Access Journals (Sweden)

    R. K. Bhan

    2016-08-01

    Full Text Available MEMS based accelerometers have already penetrated defense programs including navigation control in addition to their usual deployment in automotive, consumer and industrial markets because of their improved reliability, accuracy and excellent price performance. This paper discussed about the fabrication and testing of single axis capacitive accelerometer structures based on change in area (comb-type and change in gap (Crab type sensing principles. The accelerometers are designed for ±30 g acceleration range. A common fabrication process flow is designed for the fabrication of both types of accelerometers that are fabricated by using a three mask dissolved wafer process (DWP. Both the accelerometers showed a scale factor sensitivity of >60 mV/g at ±1 g flip test. Vibration and sensitivity testing at higher frequency was conducted on shaker table using a half sine wave shock (HSWS of 2 ms. Using HSWS test, a sensitivity in the range of ~60 mV/g was obtained for both comb or crab type structures in the 0-30 g range. It can be further tuned upto 100 mV/g by increasing the gain of the capacitance Read Out Integrated Circuit (ROIC. However, performance of the comb type of accelerometers gets affected in – 30 g to – 0 g range due to deep boron diffusion induced residual stress. The crab accelerometers showed almost linear (nonlinearity:<3 % FS behavior in the whole ±30 g range. Other tests like bias stability, bandwidth, bias temperature coefficient etc. indicate that devices are fully functional. All these observations validate our design and unified process.

  18. Reduction of the formaldehyde content in leathers treated with formaldehyde resins by means of plant polyphenols

    OpenAIRE

    Marsal Monge, Agustín; Manich Bou, Albert M.; Cuadros Domènech, Sara; Font Vallès, Joaquim

    2017-01-01

    Formaldehyde has applications in many industrial processes, including synthesis of resins and syntans to be used in the retanning process of leather. When resins are employed, they can hydrolyse, releasing formaldehyde. Due to the carcinogenicity of formaldehyde, its presence in leather should be avoided or kept below allowable limits. The aim of this study is to determine the effect of polyphenols contained in vegetable compounds (mimosa, quebracho and tara) in the reduction of the forma...

  19. Synthesis and characterization of formaldehyde by catalytic oxidation of methanol

    International Nuclear Information System (INIS)

    Salman, M.; Answer, J.; Zaman, W.U.

    2008-01-01

    The catalytic oxidation of methanol to formaldehyde is studied over copper and silver catalysts. The impact of various factors catalytic poisoning, temperature, contact time on the formaldehyde yield have been investigated. An assembly using copper and silver as catalysts has been proposed to prepare formaldehyde in perspective of Pakistan in local industry. All the conditions to optimize the formaldehyde yield were also investigated. The formaldehyde produced was standardized chemically as well as spectroscopically. (author)

  20. Characterization of the formaldehyde-H2O system using combined spectroscopic and mass spectrometry approaches

    Science.gov (United States)

    Oancea, A.; Hanoune, B.; Facq, S.; Focsa, C.; Chazallon, B.

    2009-04-01

    The atmosphere is a multiphase reactor in which physical exchange processes, heterogeneous reactions and photochemical reactions take place. The oxygenated organics (formaldehyde, ethanol, acetone etc.) present at trace concentrations into the atmosphere are known to play an important role in atmospheric chemistry due for example to their contribution in the production of HOx radicals, which largely determine the lifetime of pollutants [1]. Further, it has been shown that the interaction of oxygenated organics with ice particles in the atmosphere has the potential to promote heterogeneous chemistry [2]. In the polar lower troposphere, formaldehyde (H2CO) was measured in concentrations that are much higher that those predicted by chemistry models [3]. The mechanism at the origin of the formaldehyde production remains however controversial as the incorporation / partitioning of H2CO in ice crystal has to be determined first. Incorporation of formaldehyde into ice can take place according to several different physical mechanisms like co-condensation, riming, adsorption/desorption. The partitioning of formaldehyde between the gas phase, the liquid and the solid phases is an important parameter that leads to a better understanding of the incorporation mechanisms. In our work, different experimental approaches are used to characterize the partitioning between the different phases in which the H2O-H2CO system exists. Recently, we investigated by mass spectrometry and infrared diode laser spectroscopy the vapor liquid equilibrium (VLE) of formaldehyde aqueous solutions of different concentrations at room temperature. From the data collected on the vapor pressures at atmospherically relevant formaldehyde concentrations, we derived the Henry's coefficients at 295 K [4]. In this study we present first results on the solubility of formaldehyde in ice. This allows a better characterization of the partitioning of formaldehyde vapors above supercooled droplets and/or ice at low

  1. Photochemical decomposition of Formaldehyde in solution

    International Nuclear Information System (INIS)

    Garrido Z, G.

    1995-01-01

    In this work was studied the effect of ultraviolet radiation produced by a mercury low pressure lamp in solutions of formaldehyde. These solutions were exposed to ultraviolet rays at different times. In some of these series of solutions was added a photosensibilizer in order to obtain a high photodecomposition of formaldehyde. The techniques used for determine the products of the decomposition were the following: 1. In order to measure the residual formaldehyde and glioxal, the Hantzsch and 2,4-dinitrophenylhydrazine methods were used. 2. pH's measurements of the solutions, before and after exposition. 3. Paper's chromatography for determine presence of formed acids. 4. Acid-base tritiations for measure total acidification. We observed that when the time of exposition to UV rays was increased, a high photodecomposition of formaldehyde was formed and, besides, a greater quantity of another products. Of the reagents used like photosensibilizers, with the ruthenium reagent, the best results were obtained. (Author)

  2. Formaldehyde's Impact on Indoor Air Quality

    Science.gov (United States)

    Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.

  3. Radiation thermal transformations of formaldehyde in alcohols

    International Nuclear Information System (INIS)

    Vetrov, V.S.; Korolev, V.M.; Koroleva, G.N.; Likholap, V.F.; Khomich, F.G.

    1978-01-01

    The effect of acid and reactor gamma radiation on the interaction of formaldehyde and methanol has been studied. The radiation-thermal investigations were carried out in the range of temperatures from 150 to 230 deg C. A dose rate of n,γ-radiation amounted to 2.4x10 17 eV (gxs). From the data obtained it is concluded that the 0.01-0.1 M formic acid addition and irradiation of the methanol-formaldehyde mixture result in a substantial increase in formaldehyde consumption, the acid addition increasing the rate of formaldehyde consumption in about two times; the n,γ-radiation effect is much powerful. The rate of methylal formation increases in the presence of acid and at the temperature rise; its maximum is formed in the range of 180-190 deg C. The methyl formiate formation increases with the acid addition and temperature rise. It is concluded that radiolytic protons can accelerate methylal formation from methanol-formaldehyde solutions. The temperature rise results in the concentration increase in a free form of formaldehyde and the formation of methylal and methyl formiate

  4. Nose-only inhalation exposure system for generation, treatment and characterization of formaldehyde vapor

    Energy Technology Data Exchange (ETDEWEB)

    Leach, C.L.; Oberg, S.G.; Sharma, R.P.; Brown, D.B.

    1984-04-01

    A description of a novel symmetrical nose-only inhalation chamber for small animals is presented. The chamber utilizes a circular design and a round baffle plate around which the test atmosphere is evenly drawn in order to expose each symmetrically placed animal port to equivalent gas concentrations without exposing animals to each other's expired gases. The nose-only mode may be more suitable for inhalation exposures as compared to whole-body exposures which allow skin contamination and possible aerosol ingestion through preening habits. Evidence is presented that nose-only exposure which requires animal restraint is no more stressful than freely-caged exposure as measured by total peripheral white blood cell counts and the ease of animal entry into the restraining tubes. Applications of the exposure system are described for the case of pure formaldehyde vapor generation. The method for formaldehyde generation entails heating solid paraformaldehyde polymer in a mineral oil bath and diluting with filtered room air. The temperature of the paraformaldehyde is exponentially related to the concentration of formaldehyde concentrations and system flow rates. A 2-liter impinger collects > 95% of the formaldehyde generated at concentrations up to 100 ppm and flowrates of 15 liters per minute. Efficacy of the overall system in terms of maintenance of desired concentrations is described. A comparison of desired concentrations and measured concentrations is presented for four groups of rats exposed to formaldehyde vapor from 2 to 10 ppm.

  5. Formaldehyde-releasers : relationship to formaldehyde contact allergy. Metalworking fluids and remainder. Part 1

    NARCIS (Netherlands)

    de Groot, A.C.; Le Coz, C.J.; Lensen, G.J.; Flyvholm, M.A.; Maibach, H.I.; Coenraads, P.J.

    2010-01-01

    This is the second part of a review article on formaldehyde-releasers used as durable press chemical finishes (DPCF) in textiles. The early finishes contained large amounts of free formaldehyde, which led to many cases of allergic contact dermatitis to clothes in the 1950s and 1960s. Currently, most

  6. Thermodynamics of the formaldehyde-water and formaldehyde-ice systems for atmospheric applications.

    Science.gov (United States)

    Barret, Manuel; Houdier, Stephan; Domine, Florent

    2011-01-27

    Formaldehyde (HCHO) is a species involved in numerous key atmospheric chemistry processes that can significantly impact the oxidative capacity of the atmosphere. Since gaseous HCHO is soluble in water, the water droplets of clouds and the ice crystals of snow exchange HCHO with the gas phase and the partitioning of HCHO between the air, water, and ice phases must be known to understand its chemistry. This study proposes thermodynamic formulations for the partitioning of HCHO between the gas phase and the ice and liquid water phases. A reanalysis of existing data on the vapor-liquid equilibrium has shown the inadequacy of the Henry's law formulation, and we instead propose the following equation to predict the mole fraction of HCHO in liquid water at equilibrium, X(HCHO,liq), as a function of the partial pressure P(HCHO) (Pa) and temperature T (K): X(HCHO,liq) = 1.700 × 10(-15) e((8014/T))(P(HCHO))(1.105). Given the paucity of data on the gas-ice equilibrium, the solubility of HCHO and the diffusion coefficient (D(HCHO)) in ice were measured by exposing large single ice crystals to low P(HCHO). Our recommended value for D(HCHO) over the temperature range 243-266 K is D(HCHO) = 6 × 10(-12) cm(2) s(-1). The solubility of HCHO in ice follows the relationship X(HCHO,ice) = 9.898 × 10(-13) e((4072/T))(P(HCHO))(0.803). Extrapolation of these data yields the P(HCHO) versus 1/T phase diagram for the H(2)O-HCHO system. The comparison of our results to existing data on the partitioning of HCHO between the snow and the atmosphere in the high arctic highlights the interplay between thermodynamic equilibrium and kinetics processes in natural systems.

  7. Modeling Formaldehyde Emission in Comets

    Science.gov (United States)

    Disanti, M. A.; Reuter, D. C.; Bonev, B. P.; Mumma, M. J.; Villanueva, G. L.

    Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of these show clear emission from H2CO. We also detected H2CO with NIRSPEC in one Jupiter Family comet, 9P/Tempel 1, during Deep Impact observations. Our H2CO model, originally developed to interpret low-resolution spectra of comets Halley and Wilson (Reuter et al. 1989 Ap J 341:1045), predicts individual line intensities (g-factors) as a function of rotational temperature for approximately 1300 lines having energies up to approximately 400 cm^-1 above the ground state. Recently, it was validated through comparison with CSHELL spectra of C/2002 T7 (LINEAR), where newly developed analyses were applied to obtain robust determinations of both the rotational temperature and abundance of H2CO (DiSanti et al. 2006 Ap J 650:470). We are currently in the process of extending the model to higher rotational energy (i.e., higher rotational quantum number) in an attempt to improve the fit to high-J lines in our spectra of C/T7 and other comets. Results will be presented, and implications discussed.Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of

  8. A MEMS-based heating holder for the direct imaging of simultaneous in-situ heating and biasing experiments in scanning/transmission electron microscopes.

    Science.gov (United States)

    Mele, Luigi; Konings, Stan; Dona, Pleun; Evertz, Francis; Mitterbauer, Christoph; Faber, Pybe; Schampers, Ruud; Jinschek, Joerg R

    2016-04-01

    The introduction of scanning/transmission electron microscopes (S/TEM) with sub-Angstrom resolution as well as fast and sensitive detection solutions support direct observation of dynamic phenomena in-situ at the atomic scale. Thereby, in-situ specimen holders play a crucial role: accurate control of the applied in-situ stimulus on the nanostructure combined with the overall system stability to assure atomic resolution are paramount for a successful in-situ S/TEM experiment. For those reasons, MEMS-based TEM sample holders are becoming one of the preferred choices, also enabling a high precision in measurements of the in-situ parameter for more reproducible data. A newly developed MEMS-based microheater is presented in combination with the new NanoEx™-i/v TEM sample holder. The concept is built on a four-point probe temperature measurement approach allowing active, accurate local temperature control as well as calorimetry. In this paper, it is shown that it provides high temperature stability up to 1,300°C with a peak temperature of 1,500°C (also working accurately in gaseous environments), high temperature measurement accuracy (in-situ S/TEM imaging experiments, but also elemental mapping at elevated temperatures using energy-dispersive X-ray spectroscopy (EDS). Moreover, it has the unique capability to enable simultaneous heating and biasing experiments. © 2016 Wiley Periodicals, Inc.

  9. Teratogenic effect of formaldehyde in rabbits

    Directory of Open Access Journals (Sweden)

    A. A. Al–Saraj

    2009-01-01

    Full Text Available Thirty three pregnant rabbits were exposed to vapour of 10% formaldehyde (12 ppm throughout the gestation period to know its effect on newborns. The results showed no abortion or foetal mortality but there were some anomalies (23.8% among the newborns rabbits which includes: meromelia (6.8%, encephalocele (6.1%, Oligodactyly (4.1%, Umbilical hernia (3.4% and Short tail (3.4%; besides that small for date and decrease in the body weight of the newborns were also noticed. These findings suggest that formaldehyde is a teratogenic agent.

  10. Deuterated Formaldehyde in the low mass protostar HH212

    Science.gov (United States)

    Sahu, Dipen; Minh, YC; Lee, Chin-Fei; Liu, Sheng-Yuan; Das, Ankan; Chakrabarti, SK; Sivaraman, Bhala

    2018-01-01

    HH212, a nearby (400 pc) object in Orion, is a Class 0 protostellar system with a Keplerian disk and collimated bipolar SiO jets. Deuterated water, HDO and a deuterated complex molecule, methanol (CH2DOH) have been reported in the source. Here, we report the HDCO (deuterated formaldehyde) line observation from ALMA data to probe the inner region of HH212. We compare HDCO line with other molecular lines to understand the possible chemistry and physics of the source. The distribution of HDCO emission suggests it may be associated with the base of the outflow. The emission also shows a rotation but it is not associated with the Keplerian rotation of disk or the rotating infalling envelope, rather it is associated with the outflow as previously seen in C34S. From the possible deuterium fractionation, we speculate that the gas phase formation of deuterated formaldehyde is active in the central hot region of the low-mass protostar system, HH212.

  11. Developing a Reference Material for Formaldehyde Emissions Testing; Final Report

    Science.gov (United States)

    Exposure to formaldehyde has been shown to produce broad and potentially severe adverse human health effects. With ubiquitous formaldehyde sources in the indoor environment, formaldehyde concentrations in indoor air are usually higher than outdoors, ranging from 10 to 4000 μg/m3....

  12. Conversion and toxicity characteristics of formaldehyde in acetoclastic methanogenic sludge

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Kleerebezem, R.; Lettinga, G.

    2002-01-01

    An unadapted mixed methanogenic sludge transformed formaldehyde into methanol and formate. The methanol to formate ratio obtained was 1:1. Formaldehyde conversion proceeded without any lag phase, suggesting the constitutive character of the formaldehyde conversion enzymes involved. Because the rate

  13. Observations of Carbon Isotopic Fractionation in Interstellar Formaldehyde

    Science.gov (United States)

    Wirstrom, E. S.; Charnley, S. B.; Geppert, W. D.; Persson, C. M.

    2012-01-01

    Primitive Solar System materials (e.g. chondrites. IDPs, the Stardust sample) show large variations in isotopic composition of the major volatiles (H, C, N, and O ) even within samples, witnessing to various degrees of processing in the protosolar nebula. For ex ample. the very pronounced D enhancements observed in IDPs [I] . are only generated in the cold. dense component of the interstellar medium (ISM), or protoplanetary disks, through ion-molecule reactions in the presence of interstellar dust. If this isotopic anomaly has an interstellar origin, this leaves open the possibility for preservation of other isotopic signatures throughout the form ation of the Solar System. The most common form of carbon in the ISM is CO molecules, and there are two potential sources of C-13 fractionation in this reservoir: low temperature chemistry and selective photodissociation. While gas-phase chemistry in cold interstellar clouds preferentially incorporates C-13 into CO [2], the effect of self-shielding in the presence of UV radiation instead leads to a relative enhancement of the more abundant isotopologue, 12CO. Solar System organic material exhibit rather small fluctuations in delta C-13 as compared to delta N-15 and delta D [3][1], the reason for which is still unclear. However, the fact that both C-13 depleted and enhanced material exists could indicate an interstellar origin where the two fractionation processes have both played a part. Formaldehyde (H2CO) is observed in the gas-phase in a wide range of interstellar environments, as well as in cometary comae. It is proposed as an important reactant in the formation of more complex organic molecules in the heated environments around young stars, and formaldehyde polymers have been suggested as the common origin of chondritic insoluable organic matter (IOM) and cometary refractory organic solids [4]. The relatively high gas-phase abundance of H2CO observed in molecular clouds (10(exp- 9) - 10(exp- 8) relative to H2) makes

  14. Problems associated with the use of urea-formaldehyde foam for residential insulation. Part I. The effects of temperature and humidity on formaldehyde release from urea-formaldehyde foam insulation

    Energy Technology Data Exchange (ETDEWEB)

    Long, K.R.; Pierson, D.A.; Brennan, S.T.; Frank, C.W.; Hahne, R.A.

    1979-09-01

    The study is concerned primarily with those properties related to formaldehyde and its application as an ingredient in urea-formaldehyde resins. In particular the effects of temperature and humidity on urea-formaldehyde foam are discussed.

  15. Continuous fluorescence determination of formaldehyde in air

    Czech Academy of Sciences Publication Activity Database

    Motyka, Kamil; Mikuška, Pavel

    2004-01-01

    Roč. 518, 1-2 (2004), s. 51-57 ISSN 0003-2670 R&D Projects: GA AV ČR IAA4031105; GA ČR GA526/03/1182 Institutional research plan: CEZ:AV0Z4031919 Keywords : fluorescence * wet denuder * formaldehyde Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.588, year: 2004

  16. Edible carbohydrates from formaldehyde in a spacecraft

    Science.gov (United States)

    Weiss, A. H.

    1975-01-01

    The autocatalytic nature of the base catalyzed condensation of formaldehyde to formose sugars is eliminated by using as a cocatalyst, an aldose, or ketose having an alpha-hydrogen. This is more strongly complexed by base than is formaldehyde and the cocatalyst and sugar products accumulate as catalyst complexes instead of formaldehyde. Because of the presence of alpha-hydrogen atoms in cocatalysts and formose sugars, their removal by cross Cannizzaro reaction of complexed sugars does not occur, so the formose reaction behaves autocatalytically due to this accumulation. It is believed that a given catalytic formose complex is not a discrete complexed sugar, but rather, a scrambled dynamic mixture of sugars having weakened structures. The sugar complexes derive from a common salt-like formaldehyde complex, which, because of the absence of alpha-hydrogen, has a greater tendency to undergo Cannizzaro reaction, rather than formose condensation. Because of this, the Cannizzaro reaction can proceed without measurable formose condensation. The reverse is not possible.

  17. MODELING AND SIMULATION OF INDUSTRIAL FORMALDEHYDE ABSORBERS

    NARCIS (Netherlands)

    WINKELMAN, JGM; SIJBRING, H; BEENACKERS, AACM; DEVRIES, ET

    1992-01-01

    The industrially important process of formaldehyde absorption in water constitutes a case of multicomponent mass transfer with multiple reactions and considerable heat effects. A stable solution algorithm is developed to simulate the performance of industrial absorbers for this process using a

  18. Electrospinning formaldehyde cross-linked zein solutions

    Science.gov (United States)

    In order to develop zein fibers with improved physical properties and solvent resistance, formaldehyde was used as the cross-linking reagent before spinning. The cross-linking reaction was carried out in either acetic acid or ethanolic-HCl where the amount of cross-linking reagent was between 1 and...

  19. A study of formaldehyde sources in air

    Science.gov (United States)

    Shen, Haiwei

    Formaldehyde (CH2O) is a central component of photooxidation chemistry. The atmospheric sources of CH2O involve a complex mixture of biogenic and anthropogenic volatile organic compounds (VOCs). This study explores the geographical and altitudinal variations of CH2O production from its precursors over the Eastern U.S. and assesses the contributions from biogenic and anthropogenic VOC emissions to atmospheric CH2O. Measurements of airborne CH2O and hydrocarbons over North America and model results were used to evaluate CH2O production from its precursors. Source attribution results from a photochemical box model indicate 95% of the CH2O arose in various proportions from a mixture of methane, isoprene, methyl hydroperoxide, methanol, and a peroxyacetyl group. Methane on average contributed 32% at altitudes below 2 km to CH2O production, 43% in 2-6 km, and 52% in 6-12 km. It was the predominant CH 2O source in 1-12 km. Isoprene served as a major source of CH2 O (range 0-72%, average 17%) over the southeastern U.S. region within 0-1-km layer. Methyl hydroperoxide was one of the predominant contributors over the ocean and averaged from 6 to 33% in all layers. Production from the peroxyacetyl group and methanol were 7-17% and 10-14% on average in the layers in 0-12 km, respectively. A compound specific radiocarbon analysis technique was developed for atmospheric CH2O to examine its biogenic and anthropogenic carbon fraction. The method used filter collection, a preparative capillary gas chromatography isolation technique, and AMS detection. Ambient samples were collected on the roof of the CACS building at the Bay Campus of the University of RI, Narragansett, RI. The 14CH2O data, 48-hour back trajectories, and VOC observations from the RI Department of Environmental Management were used to assess the relative contributions of biogenic and fossil precursors to CH2O. The results show a large fraction of fossil/industrial carbon in collected CH2O samples and imply the

  20. Identification of formaldehyde-responsive genes by suppression subtractive hybridization

    International Nuclear Information System (INIS)

    Lee, Min-Ho; Kim, Young-Ae; Na, Tae-Young; Kim, Sung-Hye; Shin, Young Kee; Lee, Byung-Hoon; Shin, Ho-Sang; Lee, Mi-Ock

    2008-01-01

    Formaldehyde is frequently used in indoor household and occupational environments. Inhalation of formaldehyde invokes an inflammatory response, including a variety of allergic signs and symptoms. Therefore, formaldehyde has been considered as the most prevalent cause of sick building syndrome, which has become a major social problem, especially in developing urban areas. Further formaldehyde is classified as a genotoxicant in the respiratory tract of rats and humans. To better understand the molecular mechanisms involved in formaldehyde intoxication, we sought differentially regulated genes by formaldehyde exposure to Hs 680.Tr human trachea cells, using polymerase chain reaction (PCR)-based suppression subtractive hybridization. We identified 27 different formaldehyde-inducible genes, including those coding for the major histocompatibility complex, class IA, calcyclin, glutathione S-transferase pi, mouse double minute 2 (MDM2), platelet-derived growth factor receptor alpha, and which are known to be associated with cell proliferation and differentiation, immunity and inflammation, and detoxification. Induction of these genes by formaldehyde treatment was confirmed by reverse transcription PCR and western blot analysis. Further, the expression of calcyclin, glutathione S-transferase pi, PDGFRA and MDM2 were significantly induced in the tracheal epithelium of Sprague Dawley rats after formaldehyde inhalation. Our results suggest that the elevated levels of these genes may be associated with the formaldehyde-induced toxicity, and that they deserve evaluation as potential biomarkers for formaldehyde intoxication

  1. RAPID WAY TO ASSESS THE SAFETY OF PRODUCTS FROM PHENOL-FORMALDEHYDE PLASTICS

    Directory of Open Access Journals (Sweden)

    T. A. Kuchmenko

    2014-01-01

    Full Text Available Summary. An express method for determining of volatile components in the products of phenol-formaldehyde plastics is developed by detecting them in the equilibrium gas phase using the piezosensors array. The sorption of substances-marker vapor which are the main pollutants in the air diffusing from plastic household products has been studied under identical conditions. The array of 8 piezosensors is selected providing minimal impact of water vapor on the microbalance results; maximum sensitivity to one / several classes of organic compounds; identification of phenol / formaldehyde in the mixtures. A method of evaluation the level of emissions of phenol, formaldehyde, toluene, acetone from household plastic products is developed using the piezosensors array. It has been proposed the ranking samples nonfood polymers into groups according to the danger degree based on the total content of volatile organic compounds and the presence of phenol / formaldehyde. Accuracy of the phenol determination in polymers is verified by standard spectrophotometric method with 4-aminoantipyrine, it is shown the results of both methods satisfactorily converge. The proposed method can significantly reduce the economic and time costs on analysis and expand the analytical information about the content of other volatile substances in a single measurement.

  2. Micro-electro-mechanical system (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control

    Science.gov (United States)

    Zhang, Sean Z.; Xu, Guoda; Qiu, Wei; Lin, Freddie S.; Testa, Robert C.; Mattice, Michael S.

    2000-08-01

    A MicroElectroMechanical Systems (MEMS)-based fiber optic sensor and sensor network for improving weapon stabilization and fire control have been developed. Fabrication involves overwriting two fiber Bragg gratings (FBGs) onto a polarization-preserving optical fiber core. A MEMS diaphragm is fabricated and integrated with the overlaid FBGs to enhance the performance and reliability of the sensor. A simulation model for the MEMS fiber optic sensor and sensor network has been derived, and simulation results concerning load, angle, strain, and temperature have been obtained. The fabricated MEMS diaphragm and the overlaid FBGs have been packaged together on the basis of simulation results and mounted on a specially designed cantilever system. The combined multifunctional MEMS fiber optic sensor and sensor network is cost-effective, fast, rugged enough to operate in harsh environmental conditions, compact, and highly sensitive.

  3. Comparative Enactment of Formaldehyde-free and Formaldehyde-based Cross-linkers on Cotton Woven Fabrics

    Directory of Open Access Journals (Sweden)

    Nawshin Farzana

    2017-04-01

    Full Text Available The performances of formaldehyde-based and non-formaldehyde cross-linkers on pretreated cotton woven fabric were assessed and compared in this research. Fixapret CL was considered as the formaldehyde-based resin and Fixapret NF as the formaldehyde-free resin. Dry cross-linking method was adopted for the application of cross-linkers. Different properties of resin treated fabrics investigated and compared were as follows: DP (durable press rating, wrinkle recovery, stiff ness, tensile strength, tear strength, shrinkage, skewness, hydrophobicity, whiteness and yellowness index. Marginally low performances in smoothness appearance and dimensional stability on fabric were exhibited with formaldehyde-free cross-linkers although indicating lower amount of the strength loss percentage. The formaldehyde-based compounds imparted more yellowing tendency to the treated fabric. The formaldehyde-free resins may be a good choice of replacements considering the overall eff ectiveness on fabric

  4. Co-Adsorption of Ammonia and Formaldehyde on Regenerable Carbon Sorbents for the Primary Life Support System (PLSS)

    Science.gov (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique S.

    2016-01-01

    Results are presented on the development of a reversible carbon sorbent for trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is deemed non-regenerable, while the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. Data on concurrent sorption and desorption of ammonia and formaldehyde, which are major TCs of concern, are presented in this paper. A carbon sorbent was fabricated by dry impregnation of a reticulated carbon-foam support with polyvinylidene chloride, followed by carbonization and thermal oxidation in air. Sorbent performance was tested for ammonia and formaldehyde sorption and vacuum regeneration, with and without water present in the gas stream. It was found that humidity in the gas phase enhanced ammonia-sorption capacity by a factor larger than two. Co-adsorption of ammonia and formaldehyde in the presence of water resulted in strong formaldehyde sorption (to the point that it was difficult to saturate the sorbent on the time scales used in this study). In the absence of humidity, adsorption of formaldehyde on the carbon surface was found to impair ammonia sorption in subsequent runs; in the presence of water, however, both ammonia and formaldehyde could be efficiently removed from the gas phase by the sorbent. The efficiency of vacuum regeneration could be enhanced by gentle heating to temperatures below 60 deg.

  5. Skincare products containing low concentrations of formaldehyde detected by the chromotropic acid method cannot be safely used in formaldehyde-allergic patients.

    Science.gov (United States)

    Hauksson, I; Pontén, A; Gruvberger, B; Isaksson, M; Engfeldt, M; Bruze, M

    2016-02-01

    Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in skincare products. It has been found that formaldehyde at concentrations allowed by the European Cosmetics Directive can cause allergic contact dermatitis. However, we still lack information on whether formaldehyde at low concentrations affects dermatitis in formaldehyde-allergic individuals. To study the effects of low concentrations of formaldehyde on irritant contact dermatitis in formaldehyde-allergic individuals. Fifteen formaldehyde-allergic individuals and a control group of 12 individuals without contact allergy to formaldehyde and formaldehyde releasers were included in the study. The individuals performed the repeated open application test (ROAT) during 4 weeks with four different moisturizers releasing formaldehyde in concentrations that had been determined as > 40, 20-40, 2·5-10 and 0 p.p.m. by the chromotropic acid (CA) spot test. Dimethyloldimethylhydantoin was used as a formaldehyde releaser in the moisturizers. The ROAT was performed on areas of experimentally induced sodium lauryl sulfate dermatitis. The study was double blind, controlled and randomized. Nine of the 15 formaldehyde-allergic individuals had reappearance or worsening of dermatitis on the areas that were treated with moisturizers containing formaldehyde. No such reactions were observed in the control group (P formaldehyde in the formaldehyde-allergic individuals (P formaldehyde often found in skincare products by the CA method are sufficient to worsen an existing dermatitis in formaldehyde-allergic individuals. © 2015 British Association of Dermatologists.

  6. Investigation on formaldehyde release from preservatives in cosmetics.

    Science.gov (United States)

    Lv, C; Hou, J; Xie, W; Cheng, H

    2015-10-01

    To understand formaldehyde residue in cosmetics, an investigation on formaldehyde release from eight preservatives (methenamine - MA, paraformaldehyde - PF, poly(p-toluenesulfonamide-co-formaldehyde) -PTSAF, quaternium-15 - QU, imidazolidinyl urea - IU, diazolidinyl urea - DU, dimethyloldimethyl hydantoin - DMDM and bronopol - BP) under various conditions was performed. The concentration of released formaldehyde was determined by high-performance liquid chromatography with photodiode array detection after derivatization with 2,4-dinitrophenylhydrazine. The amounts of formaldehyde release were in the order of PF > DU > DMDM ≈ QU ≈ IU > MA > BP > PTSAF. The releasing amounts of formaldehyde were the highest in the presence of aqueous matrices for the releasers except QU and IU, and the releasing effect was also relative to pH. More formaldehyde was released with longer storage time and higher temperature. Furthermore, all preservatives in cosmetic matrices released fewer amounts of formaldehyde than in pure aqueous or organic matrices, and the formaldehyde-releasing amounts were also cosmetic specific. Formaldehyde release was dependent on the matrix, pH, time and mainly temperature, and the releasing effect was also cosmetic specific. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  7. Effectiveness of various methods of formaldehyde neutralization using monoethanolamine.

    Science.gov (United States)

    Coskey, Andrew; Gest, Thomas R

    2015-05-01

    Formaldehyde is the most commonly used fixative chemical for the preservation of human cadavers used for educational purposes in the United States. Formaldehyde is also a known carcinogenic agent whose exposure level is regulated by guidelines of the Occupational Safety and Health Administration. Various methods for formaldehyde neutralization exist, yet many donations programs do not take any steps to neutralize the formaldehyde in embalmed donor bodies. The effectiveness of monoethanolamine (MEA) in neutralizing formaldehyde is well documented when used as a final injection during embalming. The purpose of this study is to report the effectiveness of several post-embalming techniques of formaldehyde neutralization. Twenty-four donor bodies were assigned to four experimental groups of six. For the three experimental groups, the techniques tested involve delivery of a 20:1 dilution of deionized water:MEA via recannulization and gravity flow infusion, compartment injection, and alternate wetting solution containing four percent MEA. Our results indicated that spray bottle delivery was not effective in neutralization of formaldehyde compared to the control group, but that formaldehyde levels decreased when recannulization or compartment injection were used. The most effective method of formaldehyde neutralization was compartment injection of MEA solution (P embalming, compartment injection of MEA solution is an effective method of formaldehyde neutralization. © 2015 Wiley Periodicals, Inc.

  8. The microcapsule-type formaldehyde scavenger: the preparation and the application in urea-formaldehyde adhesives.

    Science.gov (United States)

    Duan, Hongyun; Qiu, Teng; Guo, Longhai; Ye, Jun; Li, Xiaoyu

    2015-08-15

    The limitation and regulation of formaldehyde emissions (FE) now shows great importance in wood-based materials such as plywood and particle board manufactured for building and furnishing materials. The widely used formaldehyde-based adhesives are one of the main sources of FE from the wood products. In this work, a new kind of long-term effective formaldehyde scavenger in the microcapsule form was prepared by using an intra-liquid desiccation method. The characterizations of the capsule (UC) were performed including the morphologies, the yields, the loading efficiency as well as its sustained-release of urea in aqueous conditions. The prepared UC could be integrated in urea-formaldehyde resins by simply physical blending, and the mixtures were available to be applied as the adhesives for the manufacture of plywood. The bonding strength (BS) and the FE of the bonded plywood in both short (3h) and long (12 week) period were evaluated in detail. It was found that the FE profile of the plywood behaved following a duple exponential law within 12 week. The addition of UC in the adhesive can effectively depress the FE of the plywood not only in a short period after preparation but also in a long-term period during its practical application. The slow released urea would continuously suppress the emission of toxic formaldehyde in a sustained manner without obviously deteriorating on the BS of the adhesives. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Afgivelse af formaldehyd fra byggevarer og forbrugerprodukter

    DEFF Research Database (Denmark)

    Kolarik, Barbara; Gunnarsen, Lars; Funch, Llis Winther

    Rapporten præsenterer resultatet af en undersøgelse af formaldehydafgivelse fra 22 mulige kilder i indeklimaet. Undersøgelsen er gennemført for om muligt at finde årsagen til de høje koncentrationer af formaldehyd i indeluften, der blev fundet i enkelte danske boliger under en foregående undersøg......Rapporten præsenterer resultatet af en undersøgelse af formaldehydafgivelse fra 22 mulige kilder i indeklimaet. Undersøgelsen er gennemført for om muligt at finde årsagen til de høje koncentrationer af formaldehyd i indeluften, der blev fundet i enkelte danske boliger under en foregående...

  10. Effect of varying levels of formaldehyde treatment of mustard oil cake on rumen fermentation, digestibility in wheat straw based total mixed diets in vitro

    Directory of Open Access Journals (Sweden)

    Mahima

    2015-04-01

    Full Text Available Aim: The aim of the current study was to protect the protein in mustard cake by different levels of formaldehyde treatment with a view to optimize the level of formaldehyde. Materials and Methods: Different levels of formaldehyde treatment (0, 1, 1.5 and 2% of crude protein containing concentrate and roughages diet in 40:60 ratio were tested for their effect on nutrients digestibility, in vitro ammonia release, in vitro gas production and change in protein fractions. Non-significant (p≤0.05 effect on pH, microbial biomass, partitioning factor, total gas production (TGP, TGP per g dry matter and TGP per g digestible dry matter (ml/g was observed in almost all the treatments. Results: Total volatile fatty acids at 2% formaldehyde treatment level of mustard cake was lower (p<0.05 as compared to other groups, while in vitro dry matter digestibility and in vitro organic matter digestibility were reported to be low in 1% formaldehyde treated group. Conclusion: On a holistic view, it could be considered that formaldehyde treatment at 1.5% level was optimal for protection of mustard oil cake protein.

  11. Effects of formaldehyde on the frog's mucociliary epithelium as a surrogate to evaluate air pollution effects on the respiratory epithelium

    Directory of Open Access Journals (Sweden)

    C. Fló-Neyret

    2001-05-01

    Full Text Available The increasing use of alcohol as an alternative fuel to gasoline or diesel can increase emission of formaldehyde, an organic gas that is irritant to the mucous membranes. The respiratory system is the major target of air pollutants and its major defense mechanism depends on the continuous activity of the cilia and the resulting constant transportation of mucous secretion. The present study was designed to evaluate the effects of formaldehyde on the ciliated epithelium through a relative large dose range around the threshold limit value adopted by the Brazilian legislation, namely 1.6 ppm (1.25 to 5 ppm. For this purpose, the isolated frog palate preparation was used as the target of toxic injury. Four groups of frog palates were exposed to diluted Ringer solution (control, N = 8 and formaldehyde diluted in Ringer solution at three different concentrations (1.25, 2.5 and 5.0 ppm, N = 10 for each group. Mucociliary clearance and ciliary beat frequency decreased significantly in contact with formaldehyde at the concentrations of 2.5 and 5.0 ppm after 60 min of exposure (P<0.05. We conclude that relatively low concentrations of formaldehyde, which is even below the Brazilian threshold limit value, are sufficient to cause short-term mucociliary impairment.

  12. A rapid liquid chromatography determination of free formaldehyde in cod.

    Science.gov (United States)

    Storey, Joseph M; Andersen, Wendy C; Heise, Andrea; Turnipseed, Sherri B; Lohne, Jack; Thomas, Terri; Madson, Mark

    2015-01-01

    A rapid method for the determination of free formaldehyde in cod is described. It uses a simple water extraction of formaldehyde which is then derivatised with 2,4-dinitrophenylhydrazine (DNPH) to form a sensitive and specific chromophore for high-performance liquid chromatography (HPLC) detection. Although this formaldehyde derivative has been widely used in past tissue analysis, this paper describes an improved derivatisation procedure. The formation of the DNPH formaldehyde derivative has been shortened to 2 min and a stabilising buffer has been added to the derivative to increase its stability. The average recovery of free formaldehyde in spiked cod was 63% with an RSD of 15% over the range of 25-200 mg kg(-1) (n = 48). The HPLC procedure described here was also compared to a commercial qualitative procedure - a swab test for the determination of free formaldehyde in fish. Several positive samples were compared by both methods.

  13. Problems associated with the use of urea-formaldehyde foam for residential insulation. Part II. The effects of temperature and humidity on free formaldehyde, extractable formaldehyde, formaldehyde emission, and physical characteristics of the foam

    Energy Technology Data Exchange (ETDEWEB)

    Schutte, W.C.; Cole, R.S.; Frank, C.W.; Long, K.R.

    1981-02-01

    Results of testing with two products of urea-formaldehyde based foams are described. Results of three products have previously been reported. Methods for detection and quantitative determination of formaldehyde, design of the experimental chambers, and the procedures are described. Samples of Product D were monitored for about 29 days and samples of Product E were monitored for 60 days in chambers and results are tabulated for formaldehyde emission. Additional tests performed on the two products are: extractable formaldehyde (high and low temperature conditions); free formaldehyde (high and low temperature conditions); comparison of free formaldehyde concentration; density (high and low temperature conditions); shrinkage (high and low temperature conditions). Control panels were constructed to simulate a wall in a home and observations were made and compared with results of the experimental products.

  14. Gas

    International Nuclear Information System (INIS)

    1996-01-01

    The French government has decided to modify the conditions of extension of local natural gas authorities to neighbouring districts. The European Union is studying the conditions of internal gas market with the objective of more open markets although considering public service requirements

  15. Formaldehyde scavengers function as novel antigen retrieval agents

    Science.gov (United States)

    Vollert, Craig T.; Moree, Wilna J.; Gregory, Steven; Bark, Steven J.; Eriksen, Jason L.

    2015-01-01

    Antigen retrieval agents improve the detection of formaldehyde-fixed proteins, but how they work is not well understood. We demonstrate that formaldehyde scavenging represents a key characteristic associated with effective antigen retrieval; under controlled temperature and pH conditions, scavenging improves the typical antigen retrieval process through reversal of formaldehyde-protein adduct formation. This approach provides a rational framework for the identification and development of more effective antigen retrieval agents. PMID:26612041

  16. BLM protein mitigates formaldehyde-induced genomic instability.

    Science.gov (United States)

    Kumari, Anuradha; Owen, Nichole; Juarez, Eleonora; McCullough, Amanda K

    2015-04-01

    Formaldehyde is a reactive aldehyde that has been classified as a class I human carcinogen by the International Agency for Cancer Research. There are growing concerns over the possible adverse health effects related to the occupational and environmental human exposures to formaldehyde. Although formaldehyde-induced DNA and protein adducts have been identified, the genomic instability mechanisms and the cellular tolerance pathways associated with formaldehyde exposure are not fully characterized. This study specifically examines the role of a genome stability protein, Bloom (BLM) in limiting formaldehyde-induced cellular and genetic abnormalities. Here, we show that in the absence of BLM protein, formaldehyde-treated cells exhibited increased cellular sensitivity, an immediate cell cycle arrest, and an accumulation of chromosome radial structures. In addition, live-cell imaging experiments demonstrated that formaldehyde-treated cells are dependent on BLM for timely segregation of daughter cells. Both wild-type and BLM-deficient formaldehyde-treated cells showed an accumulation of 53BP1 and γH2AX foci indicative of DNA double-strand breaks (DSBs); however, relative to wild-type cells, the BLM-deficient cells exhibited delayed repair of formaldehyde-induced DSBs. In response to formaldehyde exposure, we observed co-localization of 53BP1 and BLM foci at the DSB repair site, where ATM-dependent accumulation of formaldehyde-induced BLM foci occurred after the recruitment of 53BP1. Together, these findings highlight the significance of functional interactions among ATM, 53BP1, and BLM proteins as responders associated with the repair and tolerance mechanisms induced by formaldehyde. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. PILOT STUDY OF CONTACT SENSITIZATION OF FORMALDEHYDE-RELEASERS, FORMALDEHYDE AND GLUTARALDEHYDE IN DENTAL STUDENTS

    Directory of Open Access Journals (Sweden)

    Lyapina Maya

    2016-03-01

    Full Text Available Introduction: Occupational allergic contact sensitization is common in dental personnel. Some of the most common occupational allergens in dental practice are some formaldehyde-releasers, formaldehyde and glutaraldehyde. Aim: The aim of the present study was to evaluate the rate of contact sensitization to formaldehyde, quaternium-15, imidazolidinyl urea, diazolidinyl urea, and to glutaraldehyde in students of dental medicine and dental patients. Material and methods: A total of 50 participants were included in the study: 40 students of dental medicine exposed to formaldehyde-releasers, formaldehyde and glutaraldehyde during the course of their education; 10 dental patients without occupational exposure to the latter substances served as a control group. All of them were patch-tested with the studied allergens. Results: The sensitization rate to formaldehyde was significantly higher in the group of dental patients if compared to the one of dental students (χ2=5.37; p=0.021. Positive skin patch test reactions to quaternium-15 and to imidazolidinyl urea were observed only in the group of dental students. A significantly higher rate of sensitization to diazolidinyl urea, if compared to the one to imidazolidinyl urea (χ2=5.4; p=0.02 and to quaternium-15 (χ2=6.76; p=0.009, as well as to glutaraldehyde, if compared to the one to quaternium-15 (χ2=3.96; p=0.04 for the whole studied population was established. For the whole studied population, significantly increased rate of concomitant sensitization to formaldehyde and glutaraldehyde (χ2=6.18 p=0.013, as well as to diazolidinyl urea and to glutaraldehyde was established (χ2=9.12 p=0.003. Conclusions: We consider the importance of exposure to diazolidinyl urea, quaternium-15, imidazolidinyl urea and glutaraldehyde during the course of practical education in dentistry for the onset of sensitization. The exposure to formaldehyde is ubiquitous and is difficult to distinguish the roles of

  18. Degradation of formaldehyde in anaerobic sequencing batch biofilm reactor (ASBBR)

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, N.S. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil); Zaiat, M. [Laboratorio de Processos Biologicos (LPB), Departamento de Hidraulica e Saneamento, Escola de Engenharia de Sao Carlos (EESC), Universidade de Sao Paulo - USP, Engenharia Ambiental, Bloco 4-F, Av. Joao Dagnone, 1100 Santa Angelina, 13.563-120 Sao Carlos, SP (Brazil)], E-mail: zaiat@sc.usp.br

    2009-04-30

    The present study evaluated the degradation of formaldehyde in a bench-scale anaerobic sequencing batch reactor, which contained biomass immobilized in polyurethane foam matrices. The reactor was operated for 212 days at 35 deg. C with 8 h sequential cycles, under different affluent formaldehyde concentrations ranging from 31.6 to 1104.4 mg/L (formaldehyde loading rates from 0.08 to 2.78 kg/m{sup 3} day). The results indicate excellent reactor stability and over 99% efficiency in formaldehyde removal, with average effluent formaldehyde concentration of 3.6 {+-} 1.7 mg/L. Formaldehyde degradation rates increased from 204.9 to 698.3 mg/L h as the initial concentration of formaldehyde was increased from around 100 to around 1100 mg/L. However, accumulation of organic matter was observed in the effluent (chemical oxygen demand (COD) values above 500 mg/L) due to the presence of non-degraded organic acids, especially acetic and propionic acids. This observation poses an important question regarding the anaerobic route of formaldehyde degradation, which might differ substantially from that reported in the literature. The anaerobic degradation pathway can be associated with the formation of long-chain oligomers from formaldehyde. Such long- or short-chain polymers are probably the precursors of organic acid formation by means of acidogenic anaerobic microorganisms.

  19. Development of a formaldehyde biosensor with application to synthetic methylotrophy.

    Science.gov (United States)

    Woolston, Benjamin M; Roth, Timothy; Kohale, Ishwar; Liu, David R; Stephanopoulos, Gregory

    2018-01-01

    Formaldehyde is a prevalent environmental toxin and a key intermediate in single carbon metabolism. The ability to monitor formaldehyde concentration is, therefore, of interest for both environmental monitoring and for metabolic engineering of native and synthetic methylotrophs, but current methods suffer from low sensitivity, complex workflows, or require expensive analytical equipment. Here we develop a formaldehyde biosensor based on the FrmR repressor protein and cognate promoter of Escherichia coli. Optimization of the native repressor binding site and regulatory architecture enabled detection at levels as low as 1 µM. We then used the sensor to benchmark the in vivo activity of several NAD-dependent methanol dehydrogenase (Mdh) variants, the rate-limiting enzyme that catalyzes the first step of methanol assimilation. In order to use this biosensor to distinguish individuals in a mixed population of Mdh variants, we developed a strategy to prevent cross-talk by using glutathione as a formaldehyde sink to minimize intercellular formaldehyde diffusion. Finally, we applied this biosensor to balance expression of mdh and the formaldehyde assimilation enzymes hps and phi in an engineered E. coli strain to minimize formaldehyde build-up while also reducing the burden of heterologous expression. This biosensor offers a quick and simple method for sensitively detecting formaldehyde, and has the potential to be used as the basis for directed evolution of Mdh and dynamic formaldehyde control strategies for establishing synthetic methylotrophy. © 2017 Wiley Periodicals, Inc.

  20. Generation of constant formaldehyde levels for inhalation studies.

    Science.gov (United States)

    Balmat, J L

    1985-11-01

    Development of the described formaldehyde generator was undertaken to provide researchers engaged in inhalation studies with the capability to produce constant and controllable levels of formaldehyde in air. Depolymerization of purified paraformaldehyde under rigorously controlled conditions in a modified Freeland calibration manifold is employed. The desired formaldehyde concentration in the exposure chamber is achieved by adding an appropriate fraction of the generator effluent to the normal air supply to the chamber. Variation in generator formaldehyde concentration is less than +/- 11% over a three-day period and less than +/- 2% over short periods (36 seconds).

  1. Formaldehyde Crosslinking: A Tool for the Study of Chromatin Complexes*

    Science.gov (United States)

    Hoffman, Elizabeth A.; Frey, Brian L.; Smith, Lloyd M.; Auble, David T.

    2015-01-01

    Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function. PMID:26354429

  2. Formaldehyde crosslinking: a tool for the study of chromatin complexes.

    Science.gov (United States)

    Hoffman, Elizabeth A; Frey, Brian L; Smith, Lloyd M; Auble, David T

    2015-10-30

    Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Adsorption of Carbon Dioxide, Ammonia, Formaldehyde, and Water Vapor on Regenerable Carbon Sorbents

    Science.gov (United States)

    Wojtowicz, Marek A.; Cosgrove, Joseph E.; Serio, Michael A.; Wilburn, Monique

    2015-01-01

    Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Furthermore, the current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is nonregenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for simultaneous carbon dioxide, ammonia, formaldehyde, and water sorption. Multiple adsorption/vacuum-regeneration cycles were demonstrated at room temperature, and also the enhancement of formaldehyde sorption by the presence of ammonia in the gas mixture.

  4. 78 FR 51695 - Formaldehyde Emissions Standards for Composite Wood Products; Extension of Comment Period

    Science.gov (United States)

    2013-08-21

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ92 Formaldehyde Emissions Standards for Composite Wood Products..., concerning formaldehyde emissions standards for composite wood products. After receiving requests for an... CFR Part 770 Environmental protection, Formaldehyde, Reporting and recordkeeping requirements, Toxic...

  5. Formaldehyde and LeukemiA: Epidemiology, Potential Mechanisms and Implications for Risk Assessment

    Science.gov (United States)

    Formaldehyde is widely used in the United States and other countries. Occupational and environmental exposures to formaldehyde may be associated with an increased risk of leukemia in exposed individuals. However, risk assessment of formaldehyde and leukemia has been challenging ...

  6. Ambient formaldehyde measurements made at a remote marine boundary layer site during the NAMBLEX campaign – a comparison of data from chromatographic and modified Hantzsch techniques

    Directory of Open Access Journals (Sweden)

    T. J. Still

    2006-01-01

    Full Text Available Ambient formaldehyde concentrations are reported from the North Atlantic Marine Boundary Layer Experiment (NAMBLEX campaign at Mace Head on the west coast of Eire during August 2002. The results from two techniques, using direct determination via gas chromatography and the Hantzsch technique, show similar trends but a significant off set in concentrations. For westerly air flows characteristic of the marine boundary layer, formaldehyde concentrations from the gas chromatographic and Hantzsch technique ranged from 0.78–1.15 ppb and 0.13–0.43 ppb, respectively. Possible reasons for the discrepancy have been investigated and are discussed, however, no satisfactory explanation has yet been found. In a subsequent laboratory intercomparison the two techniques were in good agreement. The observed concentrations have been compared with previous formaldehyde measurements in the North Atlantic marine boundary layer and with other measurements from the NAMBLEX campaign. The measurements from the Hantzsch technique and the GC results lie at the lower and upper ends respectively of previous measurements. In contrast to some previous measurements, both techniques show distinct diurnal profiles with day maxima and with an amplitude of approximately 0.15 ppb. Strong correlations were observed with ethanal concentrations measured during NAMBLEX and the ratio of ethanal to formaldehyde determined by the gas chromatographic technique is in good agreement with previous measurements. Some simple box modelling has been undertaken to investigate possible sources of formaldehyde. Such models are not able to predict absolute formaldehyde concentrations as they do not include transport processes, but the results show that oxygenated VOCs such as ethanal and methanol are very significant sources of formaldehyde in the air masses reaching Mace Head.

  7. Low density, resorcinol-formaldehyde aerogels

    Science.gov (United States)

    Pekala, R.W.

    1988-05-26

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer ''clusters''. The covalent crosslinking of these ''clusters'' produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density less than or equal to100 mg/cc; cell size less than or equal to0.1 microns). The aerogels are transparent,dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A/degree/. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 fig., 1 tab.

  8. MEMS-based contact stress field measurements at a rough elastomeric layer: local test of Amontons’ friction law in static and steady sliding regimes

    Directory of Open Access Journals (Sweden)

    Debrégeas G.

    2010-06-01

    Full Text Available We present the results of recent friction experiments in which a MEMS-based sensing device is used to measure both the normal and tangential stress fields at the base of a rough elastomer film in frictional contact with smooth, rigid, glass indentors. We consider successively multicontacts under (i static normal loading by a spherical indentor and (ii frictional steady sliding conditions against a cylindrical indentor, for an increasing normal load. In both cases, the measured fields are compared to elastic calculations assuming (i a smooth interface and (ii Amontons’ friction law. In the static case, significant deviations are observed which decrease with increasing load and which vanish when a lubricant is used. In the steady sliding case, Amontons’ law reproduces rather satisfactorily the experiments provided that the normal/tangential coupling at the contact interface is taken into account. We discuss the origin of the difference between the Amontons fields and the measured ones, in particular the effect of the finite normal and tangential compliances of the multicontact interface.

  9. MEMS-based handheld scanning probe with pre-shaped input signals for distortion-free images in Gabor-domain optical coherence microscopy.

    Science.gov (United States)

    Cogliati, Andrea; Canavesi, Cristina; Hayes, Adam; Tankam, Patrice; Duma, Virgil-Florin; Santhanam, Anand; Thompson, Kevin P; Rolland, Jannick P

    2016-06-13

    High-speed scanning in optical coherence tomography (OCT) often comes with either compromises in image quality, the requirement for post-processing of the acquired images, or both. We report on distortion-free OCT volumetric imaging with a dual-axis micro-electro-mechanical system (MEMS)-based handheld imaging probe. In the context of an imaging probe with optics located between the 2D MEMS and the sample, we report in this paper on how pre-shaped open-loop input signals with tailored non-linear parts were implemented in a custom control board and, unlike the sinusoidal signals typically used for MEMS, achieved real-time distortion-free imaging without post-processing. The MEMS mirror was integrated into a compact, lightweight handheld probe. The MEMS scanner achieved a 12-fold reduction in volume and 17-fold reduction in weight over a previous dual-mirror galvanometer-based scanner. Distortion-free imaging with no post-processing with a Gabor-domain optical coherence microscope (GD-OCM) with 2 μm axial and lateral resolutions over a field of view of 1 × 1 mm2 is demonstrated experimentally through volumetric images of a regular microscopic structure, an excised human cornea, and in vivo human skin.

  10. Concentrations of formaldehyde in rain waters harvested at the ...

    African Journals Online (AJOL)

    Formaldehyde has been recognized as one of the most important pollutants and a carcinogen that is present in the air, water, foods, soils, fabrics, cosmetics, cigarette smoke and treated wood. Related health effects and hazards are linked to formaldehyde, depending on mode of exposure which includes: weakness, ...

  11. [Effect of formaldehyde inhalation on allergic rhinitis in mice].

    Science.gov (United States)

    Xiang, Rong; Xu, Yu

    2015-08-01

    To observe the effect of formaldehyde inhalation on the allergic rhinitis mice model. Forty-eight male BALB/C mice in six experimental group were exposure to (A) saline control; (B) Der p1; (C) formaldehyde (3.0 mg/m3); (D) Derp1 + formaldehyde (1.5 mg/m3); (E) Der p1 + formaldehyde (3.0 mg/M3); (F) Der p1+ formaldehyde (6.0 mg/m3). The concentrations of IL-4, IL-10 and IFN-γ in the peripheral serum were measured by enzyme-linked immunosorbent assay(ELISA). Nasal mucosal inflammation was evaluated by HE staining. Result: Formaldehyde exposure could increase the number of allergic rhinitis mice with sneezing and rubbing nose. The levels of IL-4 and IL-10 in group B, D, E and F were higher than that ingroup A (P formaldehyde exposure allergic rhinitis groups. The study showed that formaldehyde exposure can promote Th2 cytokines and eosinophil infiltration and then aggravate the allergic rhinitis symptoms.

  12. Influence of indoor formaldehyde pollution on respiratory system ...

    African Journals Online (AJOL)

    Background The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries. Objectives To assess the prevalence of indoor formaldehyde pollution caused by decoration and ...

  13. Formaldehyde condensation products of model phenols for conifer bark tannins

    Science.gov (United States)

    Richard W. Hemingway; Gerald W. McGraw

    1978-01-01

    Gel permeation chromatography of the condensation products of phenols and formaldehyde proved effective in understanding the reactions of condensed tannins with formaldehyde. Rates of condensation of phloroglucinols, resorcinols, catechols, (+)catechins, and (-)epicatechin were examined to determine if methylol-tannins from southern pine bark could be prepared as resin...

  14. The effect of antibiotic, disinfectant and formaldehyde gas on ...

    African Journals Online (AJOL)

    Journal of Food Technology in Africa. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 4, No 2 (1999) >. Log in or Register to get access to full text downloads.

  15. Unusual formaldehyde-induced hypersensitivity in two schoolgirls

    Energy Technology Data Exchange (ETDEWEB)

    Gammage, R.B. (Oak Ridge National Lab., TN (USA)); Hanna, W.T.; Painter, P.B. (Tennessee Univ., Knoxville, TN (USA))

    1990-01-01

    Two schoolgirls developed a syndrome resembling Henoch-Schonlein purpura while attending a recently opened school insulated with urea-formaldehyde foam (UFFI). Skin rashes and swellings were accompanied by bizarre, blue-green discoloration of the skin. Subsequent investigations by county, state and federal authorities, and low measured concentrations of formaldehyde, prompted initial conclusions that in-school formaldehyde exposures were not responsible for the girls' problems. Subsequent controlled exposures to UFFI and formaldehyde while in hospital elicited the whole cascade of symptoms. The chronology of the onset and amplification of systems make it probable that the formaldehyde exposures precipitating the girls' hypersensitivity, occurred in the school. 3 refs.

  16. CCQM-K90, formaldehyde in nitrogen, 2 μmol mol-1 Final report

    Science.gov (United States)

    Viallon, Joële; Flores, Edgar; Idrees, Faraz; Moussay, Philippe; Wielgosz, Robert Ian; Kim, D.; Kim, Y. D.; Lee, S.; Persijn, S.; Konopelko, L. A.; Kustikov, Y. A.; Malginov, A. V.; Chubchenko, I. K.; Klimov, A. Y.; Efremova, O. V.; Zhou, Z.; Possolo, A.; Shimosaka, T.; Brewer, P.; Macé, T.; Ferracci, Valerio; Brown, Richard J. C.; Aoki, Nobuyuki

    2017-01-01

    The CCQM-K90 comparison is designed to evaluate the level of comparability of national metrology institutes (NMI) or designated institutes (DI) measurement capabilities for formaldehyde in nitrogen at a nominal mole fraction of 2 μmol mol-1. The comparison was organised by the BIPM using a suite of gas mixtures prepared by a producer of specialty calibration gases. The BIPM assigned the formaldehyde mole fraction in the mixtures by comparison with primary mixtures generated dynamically by permeation coupled with continuous weighing in a magnetic suspension balance. The BIPM developed two dynamic sources of formaldehyde in nitrogen that provide two independent values of the formaldehyde mole fraction: the first one based on diffusion of trioxane followed by thermal conversion to formaldehyde, the second one based on permeation of formaldehyde from paraformaldehyde contained in a permeation tube. Two independent analytical methods, based on cavity ring down spectroscopy (CRDS) and Fourier transform infrared spectroscopy (FTIR) were used for the assignment procedure. Each participating institute was provided with one transfer standard and value assigned the formaldehyde mole fraction in the standard based on its own measurement capabilities. The stability of the formaldehyde mole fraction in transfer standards was deduced from repeated measurements performed at the BIPM before and after measurements performed at participating institutes. In addition, 5 control standards were kept at the BIPM for regular measurements during the course of the comparison. Temporal trends that approximately describe the linear decrease of the amount-of-substance fraction of formaldehyde in nitrogen in the transfer standards over time were estimated by two different mathematical treatments, the outcomes of which were proposed to participants. The two treatments also differed in the way measurement uncertainties arising from measurements performed at the BIPM were propagated to the

  17. Development of melamine modified urea formaldehyde resins based o nstrong acidic pH catalyzed urea formaldehyde polymer

    Science.gov (United States)

    Chung-Yun Hse

    2009-01-01

    To upgrade the performance of urea-formaldehyde (UF) resin bonded particleboards, melamine modified urea-formaldehyde (MUF) resins based on strong acidic pH catalyzed UF polymers were investigated. The study was conducted in a series of two experiments: 1) formulation of MUF resins based on a UF polymer catalyzed with strong acidic pH and 2) determination of the...

  18. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  19. Histone redistribution and conformational effect on chromatin induced by formaldehyde.

    Science.gov (United States)

    Polacow, I; Cabasso, L; Li, H J

    1976-10-19

    Histone redistributions between endogenous DNA in calf thymus chromatin and exogenous DNA from Clostridium perfringens (69% A + T) or from Micrococcus luteus (30% A + T) induced by 0.6 M NaCl or by 2% formaldehyde were studied by thermal denaturation. The observed redistribution occurred on histone Hl when the exogenous DNA was (A + T)-richer than the DNA in chromatin, and when the mixture was exposed to 0.6 M NaCl or formaldehyde. When a (G + C)-richer DNA was added as the acceptor for histones, no substantial transfer of histones from chromatin DNA to exogenous DNA was found. Thus the activation energy of histone dissociation from chromatin DNA seems to be substantially lowered by 0.6 M NaCl or formaldehyde such that histones (mostly histone Hl) can be dissociated and bind the (A + T)-richer DNA and form a more stable complex. It is suggested that the formaldehyde effect on histones may be due to the loss of positive charges on lysine and arginin residues (probably more on lysine than on arginine) in histones after their rapid reaction with formaldehyde. Formaldehyde treatment of chromatin also distorts the DNA conformation, as revealed by circular dichroism (CD) studies. This structural effect occurs mainly on those base pairs bound by histones other than Hl, or within the chromatin subunit. Histone redistribution is treated as a thermodynamic phenomenon of histone binding to DNA. The validity of using formaldehyde to study chromatin structure is discussed.

  20. 40 CFR 80.56 - Measurement methods for formaldehyde and acetaldehyde.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Measurement methods for formaldehyde... Measurement methods for formaldehyde and acetaldehyde. (a) Formaldehyde and acetaldehyde will be measured by....140 of this chapter for formaldehyde analysis. Diluted exhaust sample volumes must be at least 15 L...

  1. A handheld MEMS-based line-scanned dual-axis confocal microscope for early cancer detection and surgical guidance (Conference Presentation)

    Science.gov (United States)

    Chen, Ye; Yin, Chengbo; Wei, Linpeng; Glaser, Adam K.; Abeytunge, Sanjee; Peterson, Gary; Mandella, Michael J.; Sanai, Nader; Rajadhyaksha, Milind; Liu, Jonathan T.

    2017-02-01

    Considerable efforts have been recently undertaken to develop miniature optical-sectioning microscopes for in vivo microendoscopy and point-of-care pathology. These devices enable in vivo interrogation of disease as a real-time and noninvasive alternative to gold-standard histopathology, and therefore could have a transformative impact for the early detection of cancer as well as for guiding tumor-resection procedures. Regardless of the specific modality, various trade-offs in size, speed, field of view, resolution, contrast, and sensitivity are necessary to optimize a device for a particular application. Here, a miniature MEMS-based line-scanned dual-axis confocal (LS-DAC) microscope, with a 12-mm diameter distal tip, has been developed for point-of-care pathology. The dual-axis architecture has demonstrated superior rejection of out-of-focus and multiply scattered photons compared to a conventional single-axis confocal configuration. The use of line scanning enables fast frame rates (≥15 frames/sec), which mitigates motion artifacts of a handheld device during clinical use. We have developed a method to actively align the illumination and collection beams in this miniature LS-DAC microscope through the use of a pair of rotatable alignment mirrors. Incorporation of a custom objective lens, with a small form factor for in vivo application, enables the device to achieve an axial and lateral resolution of 2.0 and 1.1 microns, respectively. Validation measurements with reflective targets, as well as in vivo and ex vivo images of tissues, demonstrate that this high-speed LS-DAC microscope can achieve high-contrast imaging of fluorescently labeled tissues with sufficient sensitivity for applications such as oral cancer detection and guiding brain-tumor resections.

  2. The selective adsorption of formaldehyde and methanol over Al- or Si-decorated graphene oxide: A DFT study.

    Science.gov (United States)

    Esrafili, Mehdi D; Dinparast, Leila

    2018-03-01

    Density functional theory (DFT) calculations are performed to study the adsorption behavior of formaldehyde and methanol on the pristine as well as Al- or Si-decorated graphene oxide (GO). The most stable adsorption configurations, adsorption energies, binding distances and net charge transfers are obtained to understand the impacts of the these molecules on the electronic properties of the pristine or metal-decorated GO surface. The pristine GO exhibits a low sensitivity to both formaldehyde and methanol molecules. However, it is found that the decoration of GO with a Al or Si atom enhances its tendency to adsorb both the above gas molecules. Compared to formaldehyde, methanol is found to have a larger adsorption energy over the decorated GOs, due to the more favorable orbital interaction as well as electrostatic attraction in the resulted complexes. The amounts of charge transfer upon adsorption of formaldehyde and methanol over the Al-decorated GO are larger than those of over the Si-decorated one. Therefore, as a result of interaction with CH 2 O and CH 3 OH, the electronic properties of the Al-decorated GO change significantly. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Formaldehyde Profiler Using Laser Induced Fluorescence Technique, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Formaldehyde (HCHO) is of great interest to atmospheric scientists in NASA and other research institutions. In this SBIR project, we propose to build an airborne or...

  4. Status of iodine in formaldehyde-preserved milk - revisited

    International Nuclear Information System (INIS)

    Montgomery, D.M.; Gibson, J.E.

    1977-01-01

    The results of an investigation into the effect of formaldehyde preservation of raw milk in view of the differences observed by Murthy (J. Dairy Sci.; 45:1066 (1962) and J. Dairy Sci.; 49:1190 (1966)) and Thomas (personal communication. (1976)) are reported. The use of the specific electrode method for iodine analysis of formaldehyde-preserved milk has also been investigated. It was found that the Thomas preservation technique for 4 litre milk samples for 131 I analysis was acceptable, and an aliquot of the formaldehyde-preserved milk can be analyzed for total iodide concentration by the electrode method. Milk samples may also be preserved for stable iodide measurement (without iodide carrier addition) by addition of formaldehyde at 0.5 M concentration. (U.K.)

  5. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    Science.gov (United States)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  6. Formaldehyde cross-linking and structural proteomics: Bridging the gap.

    Science.gov (United States)

    Srinivasa, Savita; Ding, Xuan; Kast, Juergen

    2015-11-01

    Proteins are dynamic entities constantly moving and altering their structures based on their functions and interactions inside and outside the cell. Formaldehyde cross-linking combined with mass spectrometry can accurately capture interactions of these rapidly changing biomolecules while maintaining their physiological surroundings. Even with its numerous established uses in biology and compatibility with mass spectrometry, formaldehyde has not yet been applied in structural proteomics. However, formaldehyde cross-linking is moving toward analyzing tertiary structure, which conventional cross-linkers have already accomplished. The purpose of this review is to describe the potential of formaldehyde cross-linking in structural proteomics by highlighting its applications, characteristics and current status in the field. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Formaldehyde Profiler Using Laser Induced Fluorescence Technique Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Formaldehyde (HCHO) is a key trace species that is of great interest to atmospheric scientists in NASA and other research institutions. In this SBIR project, we...

  8. IRIS Toxicological Review of Formaldehyde (Inhalation) (External Review Draft 2010)

    Science.gov (United States)

    UPDATE EPA is currently revising its Integrated Risk Information System (IRIS) assessment of formaldehyde to address the 2011 NAS peer review recommendations. This assessment addresses both noncancer and cancer human health effects that are relevant to assessing ...

  9. Low-Power Formaldehyde Detector for Space Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde -- a known carcinogen -- is a significant threat to crew health. The spacecraft maximum...

  10. Low-power formaldehyde detector for space applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Trace contamination of the International Space Station (ISS) by formaldehyde?a known carcinogen? is a significant potential threat to crew health. The spacecraft...

  11. 24 CFR 3280.309 - Health Notice on formaldehyde emissions.

    Science.gov (United States)

    2010-04-01

    ... reported as a result of formaldehyde exposure. Elderly persons and young children, as well as anyone with a history of asthma, allergies, or lung problems, may be at greater risk. Research is continuing on the...

  12. Proposed residential indoor air quality guidelines for formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, N.

    2005-07-01

    This paper proposed a set of revised residential indoor air quality guidelines for formaldehyde. In the earlier guidelines, target and action levels were set at 60 {mu}g/m{sup 3} and 120 {mu}g/. However, epidemiological studies on the effects of chronic formaldehyde exposure have consistently found respiratory and allergic effects at levels below 123 {mu}g/m{sup 3}. Formaldehyde levels in home have been associated with increased risk of atopy and have also been associated with the hospitalization of children. Summaries of various epidemiological studies were presented. A summary of critical effects and the derivation of the guidelines was provided. Based on clinical studies and animal experiments, the primary effects of acute exposure to formaldehyde are the irritation of the mucosa of the upper respiratory tract and the eyes. The no observable adverse effects level (NOAEL) and lowest observable adverse effects level (LOAEL) for this outcome are 615 and 1,230 {mu}g/m{sup 3}. It was noted that an association between low-level exposure to formaldehyde and the development of allergic sensitization and asthma is biologically plausible as it is consistent with observations in animals. It was concluded that short-term exposure to formaldehyde should be limited to 123{mu}g/m{sup 3}. It was recommended that long term exposure to formaldehyde be limited to 50 {mu}g/m{sup 3}. Although formaldehyde is carcinogenic to humans, the cancer risk associated with lifelong exposure at the recommended levels is estimated to be negligible. 73 refs., 9 tabs.

  13. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Science.gov (United States)

    Schwemmer, G.; Yakshin, M.; Prasad, C.; Hanisco, T.; Mylapore, A. R.; Hwang, I. H.; Lee, S.

    2016-01-01

    We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO) fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  14. Adsorption of formaldehyde molecule on the pristine and transition metal doped graphene: First-principles study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xin [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Institute of Theoretical Chemistry, Jilin University, Changchun 130012 (China); Xu, Lei [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); College of Physics, Jilin University, Changchun, 130012 (China); Liu, Lin-Lin; Zhao, Lu-Si; Chen, Chun-Ping [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012 (China); Zhang, Yong [Department of Electrical and Computer Engineering, The University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Wang, Xiao-Chun, E-mail: wangxiaochun@jlu.edu.cn [Institute of Atomic and Molecular Physics, Jilin University, Changchun, 130012 (China); Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy (Jilin University), Changchun, 130012 (China)

    2017-02-28

    Highlights: • Formaldehyde molecule (H{sub 2}CO) is a common environmental pollutant with strong toxicity. • Total 36 different initial configurations of H{sub 2}CO molecule adsorbing onto three types of substrates have been investigated. • The Ti-doped graphene has the enough binding energy, significant changes in electronic structure, and reasonable short recovery time 10{sup −3} s. • The Ti-doped graphene is a promising candidate for detecting formaldehyde gas. - Abstract: The adsorption of H{sub 2}CO molecule on pristine and transition metal (Ti and V) doped graphene samples were investigated via a first-principles approach based on density functional theory. The most stable adsorption geometry, energy and charge transfer of H{sub 2}CO molecule on pristine and doped graphene are discussed respectively. We have found that Ti and V dopant atoms can significantly enhance the interaction between H{sub 2}CO molecule and graphene. The calculated net electron transfers, electronic density difference images and densities of states give the evidence that the H{sub 2}CO molecules stay on Ti (or V) – doped graphene by chemisorption. After H{sub 2}CO adsorption, there are significant changes in electronic structure near the Fermi level, for both two systems of Ti and V doped graphene. This indicates distinct changes of electron transport properties. We have also found that H{sub 2}CO molecule has a larger absorption energy on V-doped graphene (1.939 eV) compared with Ti-doped graphene (1.120 eV). It is shown that the Ti-doped graphene has enough binding energy, adequate changes in electronic structure and reasonable short recovery time 10{sup −3} s, making it a promising candidate for detecting formaldehyde gas.

  15. Genotoxicity of formaldehyde: Molecular basis of DNA damage and mutation

    Directory of Open Access Journals (Sweden)

    Masanobu eKawanishi

    2014-09-01

    Full Text Available Formaldehyde is commonly used in the chemical industry and is present in the environment, such as vehicle emissions, some building materials, food and tobacco smoke. It also occurs as a natural product in most organisms, the sources of which include a number of metabolic processes. It causes various acute and chronic adverse effects in humans if they inhale its fumes. Among the chronic effects on human health, we summarize data on genotoxicity and carcinogenicity in this review, and we particularly focus on the molecular mechanisms involved in the formaldehyde mutagenesis. Formaldehyde mainly induces N-hydroxymethyl mono-adducts on guanine, adenine and cytosine, and N-methylene crosslinks between adjacent purines in DNA. These crosslinks are types of DNA damage potentially fatal for cell survival if they are not removed by the nucleotide excision repair pathway. In the previous studies, we showed evidence that formaldehyde causes intra-strand crosslinks between purines in DNA using a unique method (Matsuda et al. Nucleic Acids Res. 26, 1769-1774,1998. Using shuttle vector plasmids, we also showed that formaldehyde as well as acetaldehyde induces tandem base substitutions, mainly at 5’-GG and 5’-GA sequences, which would arise from the intra-strand crosslinks. These mutation features are different from those of other aldehydes such as crotonaldehyde, acrolein, glyoxal and methylglyoxal. These findings provide molecular clues to improve our understanding of the genotoxicity and carcinogenicity of formaldehyde.

  16. Formaldehyde Levels in Traditional and Portable Classrooms: A Pilot Investigation.

    Science.gov (United States)

    Ribeiro, Isabela C; Kowalski, Peter J; Callahan, David B; Noonan, Gary P; Moffett, Daphne B; Olson, David R; Malilay, Josephine

    2016-03-01

    The pilot study discussed in this article assessed formaldehyde levels in portable classrooms (PCs) and traditional classrooms the authors evaluated formaldehyde levels in day and overnight indoor air (TCs) and explored factors influencing indoor air quality (e.g., carbon dioxide, temperature, and relative humidity). In a cross-sectional design, samples from nine PCs renovated within three years previously and three TCs in a school district in metropolitan Atlanta, Georgia. Formaldehyde levels ranged from 0.0068 to 0.038 parts per million (ppm). In both types of classroom, overnight formaldehyde median levels (PCs = 0.018 ppm; TCs = 0.019 ppm) were higher than day formaldehyde median levels (PCs = 0.011 ppm; TCs = 0.016 ppm). Carbon dioxide levels measured 470-790 ppm at 7:00 a.m. and 470-1800 ppm at 4:00 p.m. Afternoon medians were higher in TCs (1,400 ppm) than in PCs (780 ppm). Consistent with previous studies, formaldehyde levels were similar among PCs and TCs. Reducing carbon dioxide levels by improving ventilation is recommended for classrooms.

  17. Aging-associated excess formaldehyde leads to spatial memory deficits

    Science.gov (United States)

    Tong, Zhiqian; Han, Chanshuai; Luo, Wenhong; Li, Hui; Luo, Hongjun; Qiang, Min; Su, Tao; Wu, Beibei; Liu, Ying; Yang, Xu; Wan, You; Cui, Dehua; He, Rongqiao

    2013-01-01

    Recent studies show that formaldehyde participates in DNA demethylation/methylation cycle. Emerging evidence identifies that neuronal activity induces global DNA demethylation and re-methylation; and DNA methylation is a critical step for memory formation. These data suggest that endogenous formaldehyde may intrinsically link learning-responsive DNA methylation status and memory formation. Here, we report that during spatial memory formation process, spatial training induces an initial global DNA demethylation and subsequent re-methylation associated with hippocampal formaldehyde elevation then decline to baseline level in Sprague Dawley rats. Scavenging this elevated formaldehyde by formaldehyde-degrading enzyme (FDH), or enhancing DNA demethylation by a DNA demethylating agent, both led to spatial memory deficits by blocking DNA re-methylation in rats. Furthermore, we found that the normal adult rats intrahippocampally injected with excess formaldehyde can imitate the aged-related spatial memory deficits and global DNA methylation decline. These findings indicate that aging-associated excess formaldheyde contributes to cognitive decline during aging. PMID:23657727

  18. Health risks from indoor formaldehyde exposures in northwest weatherized residences

    Energy Technology Data Exchange (ETDEWEB)

    Mellinger, P.J.; Sever, L.E.

    1986-10-01

    Conflicting opinions on the potential hazards associated with formaldehyde exposure triggered a national workshop to address the toxicological questions concerning the health effects of formaldehyde. Since quantitative human data are not available to derive a dose-response curve for formaldehyde risk assessment, nonhuman data are used. In the case of formaldehyde, data from animals exposed to high concentrations are used to estimate human risk at much lower concentrations. This study presents the several steps that make up a risk assessment and examines any additional data that might alter significantly the risk estimates presented in the 1984 EIS. Rat inhalation chronic bioassay data from a study sponsored by the Chemical Industry Institute of Toxicology (CIIT) have been used to develop a risk equation that was subsequently used by BPA in its EIS. The CIIT data base remains the only acceptable animal data that can support the estimation of a dose-response curve. The development of mathematical models continues with a great deal of energy, and the use of different models is largely responsible for the great variability of the formaldehyde risk estimates. While one can calculate different values for carcinogenic risk associated with formaldehyde exposure than were presented earlier in the BPA EIS, they are not likely to be any better.

  19. Formaldehyde in dentistry: a review of mutagenic and carcinogenic potential

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, B.B.; Chestner, S.B.

    1981-09-01

    For many years there has been controversy over the value of antimicrobial drugs for intracanal dressings in endodontics. Formocresol, a formaldehyde compound, has evolved as the preferred drug for routine endodontic procedures, as well as pediatric endodontics. The increase in the use of formaldehyde has been complicated by the introduction of paraformaldehyde pastes for filling root canals. Neither of these formulas has ever been standardized. The doses are arbitrary, and the common dose of formocresol has been shown to be many times greater than the minimum dose needed for effect. The efficacy of paraformaldehyde pastes is questionable and remains clouded by inconclusive evidence, conflicting research, inadequate terminology, and a lack of convincing statistical evidence. The clinical use and delivery of formocresol and paraformaldehyde pastes remain arbitrary and unscientific. Formaldehyde has a known toxic mutagenic and carcinogenic potential. Many investigations have been conducted to measure the risk of exposure to formaldehyde; it is clear that formaldehyde poses a carcinogenic risk in humans. There is a need to reevaluate the rationale underlying the use of formaldehyde in dentistry particularly in light of its deleterious effects.

  20. MEMS-Based Inertial Measurement

    Directory of Open Access Journals (Sweden)

    S. Sabou

    2013-12-01

    Full Text Available Creating an environment for testing and verification of algorithms for navigation and orientation implemented in intelligent embedded systems is an essential step in a project development process. By testing several variants of algorithms, or a combination of the two lead to a reduced numbers of errors, which is one goal of project. A test was performed for navigation algorithm using map matching and a 2-axis accelerometer to determine speed and direction of moving a mobile unit (robot on a small map.

  1. MEMS Based Micro Aerial Vehicles

    Science.gov (United States)

    Joshi, Niranjan; Köhler, Elof; Enoksson, Peter

    2016-10-01

    Designing a flapping wing insect robot requires understanding of insect flight mechanisms, wing kinematics and aerodynamic forces. These subsystems are interconnected and their dependence on one another affects the overall performance. Additionally it requires an artificial muscle like actuator and transmission to power the wings. Several kinds of actuators and mechanisms are candidates for this application with their own strengths and weaknesses. This article provides an overview of the insect scaled flight mechanism along with discussion of various methods to achieve the Micro Aerial Vehicle (MAV) flight. Ongoing projects in Chalmers is aimed at developing a low cost and low manufacturing time MAV. The MAV design considerations and design specifications are mentioned. The wings are manufactured using 3D printed carbon fiber and are under experimental study.

  2. Formaldehyde-releasers in cosmetics : relationship to formaldehyde contact allergy Part 1. Characterization, frequency and relevance of sensitization, and frequency of use in cosmetics

    NARCIS (Netherlands)

    de Groot, Anton C.; White, Ian R.; Flyvholm, Mari-Ann; Lensen, Gerda; Coenraads, Pieter-Jan

    2010-01-01

    In this part of a series of review articles on formaldehyde-releasers and their relationship to formaldehyde contact allergy, formaldehyde-releasers in cosmetics are discussed. In this first part of the article, key data are presented including frequency of sensitization and of their use in

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

    Science.gov (United States)

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

    2010-01-01

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

  4. Volatile organic compound and formaldehyde emissions from Populus davidiana wood treated with low molecular weight urea-formaldehyde resin.

    Science.gov (United States)

    Wang, Jing-Xian; Shen, Jun; Lei, Cheng-Shuai; Feng, Qi

    2014-09-01

    Populus davidiana wood was usually impregnated with low molecular weight thermosetting resins to improve its physical and mechanical properties. However, volatile organic compounds (VOCs) and formaldehyde emitted from treated wood have lead to poor indoor air quality (IAQ). The trends of VOC and formaldehyde emissions as a function of the weight percent gain (WPG) factor were mainly investigated in this work. Aldehydes and alkanes were the predominant compositions indentified in the VOC emissions, although low amount of ketones, terpenes and alcohols were also found. With the increase in WPG, VOC and formaldehyde concentrations improved. However, their concentration began to decrease when WPG was over 44.06% (VOC) and 36.35% (formaldehyde), respectively. The modulus of elasticity (MOE) of untreated and treated wood at different WPG levels was detected. It showed that treatment of wood with UF resin significantly improved the mechanical properties. Therefore, it is probably helpful to comprehensively analyze correlations among environmental performance, mechanical performance and processing costs.

  5. Awareness, prevalence of hair smoothing products that contain formaldehyde and determinants of their harmful effects among women in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Yara Nasser Hameed

    2017-10-01

    Full Text Available Individuals who use hair smoothing products at home or in a salon work environment are at risk of exposure to various chemical compounds. Formaldehyde mixed with keratin as a hair straightening product is in common use by women in Saudi Arabia. The high temperatures used during blow-drying can release gas fumes that have several implications to include irritation of the skin, eyes and respiratory complications. Furthermore, formaldehyde is classified as a known human carcinogen. The aim of this study is to assess the source of keratin hair treatment among women, demonstrate the symptoms related to formaldehyde exposure during keratin hair treatment process and determine the practices that can increase the exposure to formaldehyde and to evaluate the level of formaldehyde in the keratin hair treatment products. A national cross-sectional survey was first conducted during March-April 2017 on Saudi Arabian children and women aged between the age of 12 and 50 years old. A standardized, fully confidential questionnaire was provided to participating members. A total of 330 filled questionnaires were obtained within the study location. Moreover, 30 hair salons that used keratin-based products were visited in 3 different cities in Al Qassim province to check the location of keratin hair treatment, ventilation procedures and take samples of hair products that were later analyzed. Most commonly reported symptom was irritation of the eyes reported by 135 people. Other symptoms described include irritation of throat, burning sensation of the nose, headache and nausea. Argan e Ojon was one of the most famous product tested in this study with formaldehyde levels above 0.2% threshold (0.35%. It is worrying thatArgan e Ojon does not comply with GSO 1943 and SASO 1953 standards. A majority of salons demonstrated poor ventilation measures and failed to isolate their clients from the general public and salon workers. With the evident complications, more should be

  6. A review of the effects of formaldehyde release from endodontic materials.

    Science.gov (United States)

    Athanassiadis, B; George, G A; Abbott, P V; Wash, L J

    2015-09-01

    Formaldehyde is present in most living cells and the environment. In dentistry, patients may be exposed to formaldehyde through the use of several endodontic materials (e.g. AH 26) and during formocresol pulpotomies. This review outlines how the human body reacts to formaldehyde exposure, how recent data has relooked at the issue of carcinogenicity and leukaemia associated with formaldehyde, and whether it is possible to quantify the amount of formaldehyde produced by endodontic cements. The review analyses the way formaldehyde is produced from epoxy resins and addresses the question of whether the amount of formaldehyde from endodontic cements is large enough to override the body's ability to deal with its own endogenous levels of formaldehyde and should the amount of formaldehyde produced be a concern. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  7. THE PHOTODISSOCIATION OF FORMALDEHYDE IN COMETS

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Paul D., E-mail: pfeldman@jhu.edu [Department of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States)

    2015-10-20

    Observations of comets in the 905–1180 Å spectral band made with the Far Ultraviolet Spectroscopic Explorer in 2001 and 2004 show unusual features in the fluorescent emissions of CO and H{sub 2}. These include emission from a non-thermal high-J rotational population of CO and solar Lyα induced fluorescence from excited vibrational levels of H{sub 2}, both of which are attributed to the photodissociation of formaldehyde. In this paper we model the large number of observed H{sub 2} lines and demonstrate the dependence of the pumping on the heliocentric velocity of the comet and the solar line profiles. We also derive the rotational and vibrational populations of H{sub 2} and show that they are consistent with the results of laboratory studies of the photodissociation of H{sub 2}CO. In addition to the principal series of H i and O i, the residual spectrum is found to consist mainly of the Rydberg series of C i multiplets from which we derive the mean carbon column abundance in the coma. Fluorescent emissions from N i and N{sub 2} are also searched for.

  8. Indoor air quality: radon and formaldehyde

    International Nuclear Information System (INIS)

    1986-01-01

    The WHO Regional Office for Europe has taken a leading role at the international level in reviewing and stimulating research and action on the potential health hazards of indoor air pollutants. A subject is given on page vi. It is now much more generally recognized than even five years ago that the use of particular materials for construction of buildings or for furniture and fittings is accompanied by certain risks, especially in view of the ''tightening'' of buildings to reduce energy costs, and increased reliance on central heating and air conditioning. For the last three years, the Regional Office, with the support of the Government of the Netherlands, has been developing a set of air quality guidelines for Europe. In addition to major air pollutants such as sulfur dioxide and particulates, these guidelines cover some 25 other inorganic and organic substances, including radon and formaldehyde. In 1985, a working group reviewed the latter two substances in relation to the ongoing indoor air quality programme of the Regional Office and also as part of the air quality guidelines. In view of the importance of these substances, it was decided to issue a separate report in the Environmental Health Series. The complete air quality guidelines will be published in mid-1987. (author)

  9. Exposure to formaldehyde: a challenge of occupational health significance

    International Nuclear Information System (INIS)

    Kaonga, K.

    2009-01-01

    The use of formaldehyde as the fixative for general microscopic demonstration of tissues in medical laboratory establishments is as significant as the diagnosis of the underlying ailment. Instantaneous human exposure to formaldehyde elicits symptoms that may include watery eyes, headache, inflamed throat and dyspnea. The gaseous chemical is toxic, allergenic and carcinogenic. A study to determine the incidence of human exposure to formaldehyde was carried out at the University Teaching Hospital in Lusaka, Zambia from January to December, 2007. Anonymous questionnaires on various aspects of human exposure to formaldehyde were given to laboratory technical personnel. Exposure to formaldehyde was determined using general consideration model comprising points awarded to participants according to their responses. Five points represented the maximum level of exposure, while one point denoted the minimum encounter. There were 8 incidents of formaldehyde pollution, with five being emissions from 210-litre formalin receptacles whose stoppers were inadvertently left loose overnight, while three involved accidental breakage of Winchester bottles of formalin. A total of 115 people were exposed during the year. Fifteen (13.0 percent) participants scored one point each, while 20 (17.4 percent) participants obtained 2 points each. Thirty-five (30.4 percent) participants got 3 points each, while 30 (26.0 percent) participants received 4 points each. Twenty-five (21.7 percent) participants attained 5 points each. Human exposure to formaldehyde is an issue of occupational health concern. Participants with a score of 3 points or more need regular medical check ups in order to safeguard their health. Programs on effective management of hazardous chemicals are worth setting up.(author)

  10. Optical chemical sensors for atmospheric pollutants based on nano porous materials: application to the formaldehyde and the other carbonyl compounds

    International Nuclear Information System (INIS)

    Paolacci, H.

    2006-12-01

    Formaldehyde, a well-identified indoor pollutant, was recently classified as carcinogenic. New regulations for the air quality are expected and therefore there is a need for low-cost sensors, sensitive and selective with a fast response time for the detection of formaldehyde at ppb level. In the present work, we had developed a chemical sensor based on nano-porous matrices doped with Fluoral-P and optical methods of detection. The nano-porous matrices, elaborated via the Sol-Gel process, display nano-pores whose cavity is tailored for the trapping of the targeted pollutant. They provide a first selectivity with the discrimination of the pollutants by their size. A second selectivity is obtained with a molecular probe, Fluoral-P, which reacts specifically with formaldehyde leading to the 3,5- di-acetyl-1,4-dihydro-lutidine (DDL). The kinetics of formation of DDL was studied as function of many parameters such as the concentration of Fluoral-P in the matrix, the pollutant content in gas mixture, the flow rate, the relative humidity of the gas mixtures and interference with other carbonylated compounds. The present chemical sensor can detect, via absorbance measurements, 2 ppb of formaldehyde within 30 min over a O to 60% relative humidity range. Moreover, to detect the total carbonylated compounds, we also explored the potentiality of a chemical sensor using, as a probe molecule, the 2'4-dinitro-phenyl-hydrazine which forms with these compounds the corresponding hydrazones derivatives. A patent was deposited for these two sensors. We have also developed a semi-miniaturized prototype for demonstration, using a flow cell, a miniaturized spectrophotometer, a light source and a lap-top. (author)

  11. Mortality from lymphohematopoietic malignancies among workers in formaldehyde industries.

    Science.gov (United States)

    Hauptmann, Michael; Lubin, Jay H; Stewart, Patricia A; Hayes, Richard B; Blair, Aaron

    2003-11-05

    Many U.S. factory workers are exposed to formaldehyde. Although increased risks for leukemia have been found in medical workers and other professionals exposed to formaldehyde, studies in industrial workers, who are thought to have higher exposures, have shown inconsistent associations. We extended follow-up of a cohort of industrial workers to evaluate the association between formaldehyde exposure and lymphohematopoietic cancers. The cohort consisted of 25 619 workers (865 708 person-years) employed before January 1, 1966, at one of 10 U.S. industrial plants and followed through December 31, 1994. We analyzed formaldehyde exposure (peak exposure, average exposure intensity, cumulative exposure, and duration of exposure) and mortality from lymphohematopoietic malignancies using standardized mortality ratios and relative risks and 95% confidence intervals (CIs) based on Poisson regression. Statistical tests were two-sided. Among the cohort, there were 178 deaths from lymphohematopoietic malignancies. Relative risks for leukemia (69 deaths), particularly for myeloid leukemia (30 deaths), increased with formaldehyde exposure. Compared with workers exposed to low peak levels of formaldehyde (0.1-1.9 ppm), relative risks for myeloid leukemia were 2.43 (95% CI = 0.81 to 7.25) and 3.46 (95% CI = 1.27 to 9.43) for workers exposed to peak levels of 2.0-3.9 ppm and > or = 4.0 ppm, respectively (P(trend) =.009). Compared with workers exposed to low levels of average exposure intensity of formaldehyde (0.1-0.4 ppm), workers exposed to 0.5-0.9 ppm and > or = 1.0 ppm average intensity had relative risks of 1.15 (95% CI = 0.41 to 3.23) and 2.49 (95% CI = 1.03 to 6.03), respectively (P(trend) =.088). The relative risk for leukemia was not associated with cumulative exposure but was weakly associated with duration of exposure. Relative risks for Hodgkin's disease also increased with formaldehyde exposure. Exposure to formaldehyde may cause leukemia, particularly myeloid leukemia

  12. Mammals divert endogenous genotoxic formaldehyde into one-carbon metabolism.

    Science.gov (United States)

    Burgos-Barragan, Guillermo; Wit, Niek; Meiser, Johannes; Dingler, Felix A; Pietzke, Matthias; Mulderrig, Lee; Pontel, Lucas B; Rosado, Ivan V; Brewer, Thomas F; Cordell, Rebecca L; Monks, Paul S; Chang, Christopher J; Vazquez, Alexei; Patel, Ketan J

    2017-08-31

    The folate-driven one-carbon (1C) cycle is a fundamental metabolic hub in cells that enables the synthesis of nucleotides and amino acids and epigenetic modifications. This cycle might also release formaldehyde, a potent protein and DNA crosslinking agent that organisms produce in substantial quantities. Here we show that supplementation with tetrahydrofolate, the essential cofactor of this cycle, and other oxidation-prone folate derivatives kills human, mouse and chicken cells that cannot detoxify formaldehyde or that lack DNA crosslink repair. Notably, formaldehyde is generated from oxidative decomposition of the folate backbone. Furthermore, we find that formaldehyde detoxification in human cells generates formate, and thereby promotes nucleotide synthesis. This supply of 1C units is sufficient to sustain the growth of cells that are unable to use serine, which is the predominant source of 1C units. These findings identify an unexpected source of formaldehyde and, more generally, indicate that the detoxification of this ubiquitous endogenous genotoxin creates a benign 1C unit that can sustain essential metabolism.

  13. Formaldehyde as a basis for residential ventilation rates

    Energy Technology Data Exchange (ETDEWEB)

    Sherman, M.H.; Hodgson, A.T.

    2002-04-28

    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.

  14. Engineering and analysis of a Saccharomyces cerevisiae strain that uses formaldehyde as an auxiliary substrate

    NARCIS (Netherlands)

    Baerends, Richard J. S.; de Hulster, Erik; Geertman, Jan-Maarten A.; Daran, Jean-Marc; van Maris, Antonius J. A.; Veenhuis, Marten; van der Klei, Ida J.; Pronk, Jack T.

    We demonstrated that formaldehyde can be efficiently coutilized by an engineered Saccharomyces cerevisiae strain that expresses Hansenula polymorpha genes encoding formaldehyde dehydrogenase (FLD1) and formate dehydrogenase (FMD), in contrast to wild-type strains. Initial chemostat experiments

  15. Melamine–Glyoxal–Glutaraldehyde Wood Panel Adhesives without Formaldehyde

    Directory of Open Access Journals (Sweden)

    Xuedong Xi

    2017-12-01

    Full Text Available (MGG’ resin adhesives for bonding wood panels were prepared by a single step procedure, namely reacting melamine with glyoxal and simultaneously with a much smaller proportion of glutaraldehyde. No formaldehyde was used. The inherent slow hardening of this resin was overcome by the addition of N-methyl-2-pyrrolidone hydrogen sulphate ionic liquid as the adhesive hardener in the glue mix. The plywood strength results obtained were comparable with those obtained with melamine–formaldehyde resins pressed under the same conditions. Matrix assisted laser desorption ionisation time of flight (MALDI ToF and Fourier transform Infrared (FTIR analysis allowed the identification of the main oligomer species obtained and of the different types of linkages formed, as well as to indicate the multifaceted role of the ionic liquid. These resins are proposed as a suitable substitute for equivalent formaldehyde-based resins.

  16. The margin of exposure to formaldehyde in alcoholic beverages.

    Science.gov (United States)

    Monakhova, Yulia B; Jendral, Julien A; Lachenmeier, Dirk W

    2012-06-01

    Formaldehyde has been classified as carcinogenic to humans (WHO IARC group 1). It causes leukaemia and nasopharyngeal cancer, and was described to regularly occur in alcoholic beverages. However, its risk associated with consumption of alcohol has not been systematically studied, so this study will provide the first risk assessment of formaldehyde for consumers of alcoholic beverages.Human dietary intake of formaldehyde via alcoholic beverages in the European Union was estimated based on WHO alcohol consumption data and literature on formaldehyde contents of different beverage groups (beer, wine, spirits, and unrecorded alcohol). The risk assessment was conducted using the margin of exposure (MOE) approach with benchmark doses (BMD) for 10 % effect obtained from dose-response modelling of animal experiments.For tumours in male rats, a BMD of 30 mg kg(-1) body weight per day and a "BMD lower confidence limit" (BMDL) of 23 mg kg(-1) d(-1) were calculated from available long-term animal experiments. The average human exposure to formaldehyde from alcoholic beverages was estimated at 8·10(-5) mg kg(-1) d(-1). Comparing the human exposure with BMDL, the resulting MOE was above 200,000 for average scenarios. Even in the worst-case scenarios, the MOE was never below 10,000, which is considered to be the threshold for public health concerns.The risk assessment shows that the cancer risk from formaldehyde to the alcohol-consuming population is negligible and the priority for risk management (e.g. to reduce the contamination) is very low. The major risk in alcoholic beverages derives from ethanol and acetaldehyde.

  17. Preliminary study: Formaldehyde exposure in laboratories of Sharjah university in UAE

    OpenAIRE

    Ahmed, Hafiz Omer

    2011-01-01

    Objectives : Laboratory technicians, students, and instructors are at high risk, because they deal with chemicals including formaldehyde. Thus, this preliminary study was conducted to measure the concentration of formaldehyde in the laboratories of the University of Sharjah in UAE. Materials and Methods: Thirty-two air samples were collected and analyzed for formaldehyde using National Institute for Occupational Safety and Health (NIOSH) method 3500. In this method, formaldehyde reacts with c...

  18. Preparation and characterization of phloroglucinol-formaldehyde aerogel

    International Nuclear Information System (INIS)

    Huang Changgang; China Academy of Engineering Physics, Mianyang; Tang Yongjian; Wang Chaoyang; Yan Hongmei

    2006-01-01

    Phloroglucinol-formaldehyde (PF) aerogels and carbonized PF (CPF) aerogels were prepared from Phloroglucinol (P) and Formaldehyde (F) by sol-gel, solvent exchanging, supercritical drying and carbonization processes. The aerogel has a large specific surface area, continuous nano-network and porous structure. The density and mean porosity radius will enlarge after being carbonized, while the specific surface area will be influenced little. The micro-structure and density of aerogel are controlled by concentration of total reactants and catalyzer, respectively. Aerogels with different micro-structure and different density fit for ICF targets can be prepared by optimizing synthesis conditions. (authors)

  19. [Cognitive disorders in workers engaged into formaldehyde and methanol production].

    Science.gov (United States)

    Maliutina, N N; Taranenko, L A

    2014-01-01

    The authors studied cognitive functions state in workers engaged into chemical production under exposure to combination of factors with prevalent methanol and formaldehyde. Study covered 128 examinees of main occupations and 89 individuals of reference group. Through periodic medical examinations, state of cognitive functions was assessed by Montreal scale (MCA). Findings are increased serum levels of methanol and formaldehyde in the main group members. Moderate cognitive disorders of multifunctional type were seen. Associations of these disorders with acting agents were studied, and high degree of their correlations with occupation was revealed.

  20. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    Directory of Open Access Journals (Sweden)

    Schwemmer G.

    2016-01-01

    Full Text Available We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  1. Separation of long RNA by agarose-formaldehyde gel electrophoresis.

    Science.gov (United States)

    Mansour, Farrah H; Pestov, Dimitri G

    2013-10-01

    We describe a method to facilitate electrophoretic separation of high-molecular-weight RNA species, such as ribosomal RNAs and their precursors, on agarose-formaldehyde gels. Two alternative "pK-matched" buffer systems were substituted for the traditionally used Mops-based conductive medium. The key advantages include shortened run times, a 5-fold reduction in formaldehyde concentration, a significantly improved resolution of long RNAs, and consistency in separation. The new procedure has a streamlined work flow that helps to minimize errors and is broadly applicable to agarose gel electrophoresis of RNA samples and their subsequent analysis by Northern blotting. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Synthesis and thermal degradation studies of melamine formaldehyde resins.

    Science.gov (United States)

    Ullah, Sami; Bustam, M A; Nadeem, M; Naz, M Y; Tan, W L; Shariff, A M

    2014-01-01

    Melamine formaldehyde (MF) resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA). The maximum percentage of solid content (69.7%) was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increase of melamine monomer concentration. The highest residual weight 14.125 wt.% was obtained with sample 10.

  3. Synthesis and Thermal Degradation Studies of Melamine Formaldehyde Resins

    Directory of Open Access Journals (Sweden)

    Sami Ullah

    2014-01-01

    Full Text Available Melamine formaldehyde (MF resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA. The maximum percentage of solid content (69.7% was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increase of melamine monomer concentration. The highest residual weight 14.125 wt.% was obtained with sample 10.

  4. Studies on the reaction of glutathione and formaldehyde using NMR.

    Science.gov (United States)

    Hopkinson, Richard J; Barlow, Philippa S; Schofield, Christopher J; Claridge, Timothy D W

    2010-11-07

    Within cells it is proposed that a major mechanism for the metabolism of formaldehyde is via its reaction with glutathione (GSH) to form S-hydroxymethylglutathione (HMG), which undergoes subsequent oxidation. In addition to HMG and the previously reported (5R,10S)-5-(carboxymethylcarbamoyl)-7-oxo-3-thia-1,6-diazabicyclo[4.4.1]undecane-10-carboxylic acid (BiGF(2)), NMR studies on the reaction of GSH with formaldehyde reveal two previously unassigned monocyclic structures. The results imply that the biologically relevant reactions between aldehydes and peptides/proteins may be more complex than presently perceived.

  5. DFT study of formaldehyde adsorption on vacancy defected graphene doped with B, N, and S

    International Nuclear Information System (INIS)

    Zhou, Qingxiao; Yuan, Lei; Yang, Xi; Fu, Zhibing; Tang, Yongjian; Wang, Chaoyang; Zhang, Hong

    2014-01-01

    Highlights: • The existence of vacancy in graphene enhanced the adsorption of H 2 CO molecule. • There was chemical bond forming between H 2 CO molecule and dopants (B, N, and S) in modified graphene. • The adsorption of H 2 CO molecule changed the conductivity of B and S doped defected graphene. - Abstract: The adsorption of formaldehyde (H 2 CO) on modified graphene sheets, combining vacancy and dopants (B, N, and S), was investigated by employing the density functional theory (DFT). It was found that the vacancy-defected graphene was more sensitive to absorb H 2 CO molecule compared with the pristine one. Furthermore, the H 2 CO molecule tended to be chemisorbed on vacancy-defected graphene with dopants, which exhibited larger adsorption energy and net charge transfer than that of one without dopants. The results of partial electronic density of states (PDOS) indicated that the defect-dopant combination effect on the adsorption process was mainly owing to the contribution of the hybridization between dopants and C atoms around the vacancy. We hope our results will be useful for the application of graphene for chemical sensors to detect formaldehyde gas

  6. Effect of formaldehyde on the upper respiratory tract _ormal flora of ...

    African Journals Online (AJOL)

    Background: Formaldehyde is a chemical that is used to fix a tissue after death or removal from the body to prevent autolysis and putrefaction. Exposure to formaldehyde can occur as a result of occupation. Objective: To determine the effect of the formaldehyde on the throat and nasal flora of upper respiratory tract of rabbits ...

  7. 40 CFR 721.3810 - Formaldehyde, polymers with substituted phenols (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymers with... New Uses for Specific Chemical Substances § 721.3810 Formaldehyde, polymers with substituted phenols... identified generically as Formaldehyde, polymers with substituted phenols (PMN P-99-0558) is subject to...

  8. How mole ratio of UF resin affects formaldehyde emission and other properties : a literature critique

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical review was made of the literature concerned with how the formaldehyde to urea mole ratio (F/U) affects formaldehyde emission from particleboard and plywood bonded with urea-formaldehyde (UF) adhesives, and how this ratio affects certain other adhesive and board properties. It is difficult to quantify the dependence of various properties on mole ratio or...

  9. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated (PMN...

  10. 40 CFR 721.7046 - Formaldehyde, polymer with substituted phenols, glycidyl ether.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with substituted... New Uses for Specific Chemical Substances § 721.7046 Formaldehyde, polymer with substituted phenols... substance identified as formaldehyde, polymer with substituted phenols, glycidyl ether (PMN P-93-955) is...

  11. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with 1... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3...

  12. 40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, condensated... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

  13. 40 CFR 721.10134 - Formaldehyde, polymer with dialkylphenylamine, dialkylphenol and trimethylhexanediamine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10134 Formaldehyde, polymer... significant new uses subject to reporting. (1) The chemical substance identified generically as formaldehyde...

  14. 75 FR 17163 - Formaldehyde Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2010-04-05

    ... Occupational Safety and Health Administration Formaldehyde Standard; Extension of the Office of Management and... specified in the Standard on Formaldehyde (29 CFR 1910.1048). The standard protects workers from the adverse health effects from occupational exposure to Formaldehyde. DATES: Comments must be submitted (postmarked...

  15. 78 FR 44089 - Formaldehyde Emissions Standards for Composite Wood Products; Extension of Comment Period

    Science.gov (United States)

    2013-07-23

    ... AGENCY 40 CFR Part 770 RIN 2070-AJ92 Formaldehyde Emissions Standards for Composite Wood Products..., concerning formaldehyde emissions standards for composite wood products. This document extends the comment..., Formaldehyde, Reporting and recordkeeping requirements, Toxic substances, Wood. Dated: July 17, 2013. James...

  16. Relationship between formaldehyde and quaternium-15 contact allergy. Influence of strength of patch test reactions

    NARCIS (Netherlands)

    de Groot, Anton C.; Blok, Janine; Coenraads, Pieter-Jan

    2010-01-01

    Objectives: To test our hypothesis that patients with stronger patch test reactions to formaldehyde are more likely to react to quaternium-15, attesting to the aetiological role for formaldehyde in such co-reactivity. Methods: Retrospective analysis of all patients patch tested with formaldehyde and

  17. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin (PMN...

  18. Contact allergic dermatitis from melamine formaldehyde resins in a patient with a negative patch-test reaction to formaldehyde.

    Science.gov (United States)

    García Gavin, Juan; Loureiro Martinez, Manuel; Fernandez-Redondo, Virginia; Seoane, Maria-José; Toribio, Jaime

    2008-01-01

    Melamine paper is a basic material used in the furniture industry for home and office interiors. Contact allergic dermatitis from melamine formaldehyde resins (MFRs) should be considered in patients who work on melamine paper impregnation lines. We report a case of a 28-year-old female plywood worker who developed eczema on the dorsal side of her hands and wrists after 2 years of working on the melamine paper impregnation line. She had a relevant positive patch-test reaction to MFR, with a negative reaction to formaldehyde. Contact dermatitis due to MFR is not common, and it is usually related to products that are not fully cured or to close contact with intermediate products on the assembly line. Formaldehyde release from MFR can explain most of the positive responses. To our knowledge, this is the first report of MFR contact allergic dermatitis in a worker on a melamine paper impregnation line.

  19. levels of formaldehyde and acetaldehyde in selected bottled ...

    African Journals Online (AJOL)

    Accer

    ABSTRACT. The levels of formaldehyde and acetaldehyde in bottled drinking water and the effect of storage time and storage conditions on their levels were determined. A total of 144 samples of six brands of bottled drinking water were purchased from Dar es Salaam, Iringa, Mwanza and Arusha regions in Tanzania.

  20. Melamine-modified urea formaldehyde resin for bonding particleboards

    Science.gov (United States)

    Chung-Yun Hse; Feng Fu; Hui Pan

    2008-01-01

    For the development of a cost-effective melamine-modified urea formaldehyde resin (MUF), the study evaluated the effects of reaction pH and melamine content on resin properties and bond performance of the MUF resin adhesive systems. Eight resins, each with three replicates, were prepared in a factorial experiment that included two formulation variables: two reaction...

  1. Sol-gel based sensor for selective formaldehyde determination

    International Nuclear Information System (INIS)

    Bunkoed, Opas; Davis, Frank; Kanatharana, Proespichaya; Thavarungkul, Panote; Higson, Seamus P.J.

    2010-01-01

    We report the development of transparent sol-gels with entrapped sensitive and selective reagents for the detection of formaldehyde. The sampling method is based on the adsorption of formaldehyde from the air and reaction with β-diketones (for example acetylacetone) in a sol-gel matrix to produce a yellow product, lutidine, which was detected directly. The proposed method does not require preparation of samples prior to analysis and allows both screening by visual detection and quantitative measurement by simple spectrophotometry. The detection limit of 0.03 ppmv formaldehyde is reported which is lower than the maximum exposure concentrations recommended by both the World Health Organisation (WHO) and the Occupational Safety and Health Administration (OSHA). This sampling method was found to give good reproducibility, the relative standard deviation at 0.2 and 1 ppmv being 6.3% and 4.6%, respectively. Other carbonyl compounds i.e. acetaldehyde, benzaldehyde, acetone and butanone do not interfere with this analytical approach. Results are provided for the determination of formaldehyde in indoor air.

  2. Harmful Effects of Formaldehyde and Possible Protective Effect of ...

    African Journals Online (AJOL)

    2017-05-22

    May 22, 2017 ... paraformaldehyde at a temperature of 35–40°C in specifically prepared glass assembly. Each group (n = 7) were placed in glass cages (50 cm × 20 cm ..... 7. Zararsiz I, Kus I, Akpolat N, Songur A, Ogeturk M,. Sarsilmaz M. Protective effects of omega-3 essential fatty acids against formaldehyde-induced ...

  3. Dispersion adhesives from soy flour and phenol formaldehyde

    Science.gov (United States)

    Charles R. Frihart; James M. Wescott; Amy E. Traska

    2007-01-01

    Higher petroleum prices and greater interest in bio-based adhesives have stimulated a considerable amount of research on incorporating soybean flour into wood adhesives in recent years. In some cases, soy was used at low levels as an extender for phenol-formaldehyde (PF) adhesives; in other cases, highly hydrolyzed soy flour was used. Although progress was made in...

  4. IRIS Toxicological Review of Formaldehyde (Interagency Science Consultation Draft)

    Science.gov (United States)

    On June 2, 2010, the Toxicological Review of Formaldehyde and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices...

  5. Influence of indoor formaldehyde pollution on respiratory system ...

    African Journals Online (AJOL)

    Some adults surveyed complained of common respiratory system disorders, including coughing (11.8%), nasal irritation (39.2%), Heterosmia (14.51%), and throat irritation (25.27%); 12% of children suffered from asthma. The analysis identified formaldehyde pollution and ventilation frequency as risk factors for respiratory ...

  6. Levels of formaldehyde and acetaldehyde in selected bottled ...

    African Journals Online (AJOL)

    The levels of formaldehyde and acetaldehyde in bottled drinking water and the effect of storage time and storage conditions on their levels were determined. A total of 144 samples of six brands of bottled drinking water were purchased from Dar es Salaam, Iringa, Mwanza and Arusha regions in Tanzania. Analysis was ...

  7. Effect of different catalysts on urea-formaldehyde resin synthesis

    Science.gov (United States)

    Qi-Ning Sun; Chung-Yun Hse; Todd F. Shupe

    2014-01-01

    Four catalysts (H2SO4, HCl, H3PO4, and NaOH/NH4OH) were studied in the preparation of melamine modified urea– formaldehyde (UFM) resins. 13C-nuclear magnetic resonance spectroscopic analysis of the UFM resins at different synthesis stages revealed the...

  8. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    This work presents a study of the deactivation behavior of Fe-Mo oxide catalyst during selective oxidation of methanol to formaldehyde in a period of 5 days. The structural changes in the catalyst have been investigated in situ for the initial 10 h by Raman spectroscopy, and the structure after 5...

  9. 78 FR 34820 - Formaldehyde Emissions Standards for Composite Wood Products

    Science.gov (United States)

    2013-06-10

    ..., and thus endogenous levels are present in the body. In 1991, EPA classified formaldehyde as a probable... reviewed in 2011 (Ref. 10). While the economic analysis of cancer benefits is based on the unit risk, which.... Hardwood plywood--a. General definition. The statute defines the term ``hardwood plywood'' as a hardwood or...

  10. The histological effects of formaldehyde vapour on the lungs ...

    African Journals Online (AJOL)

    This study was designed to investigate the effects 40% formaldehyde inhalation on the lungs. Twenty adult male albino rats were used for this study and they were subdivided into five groups (A, B, C, D, and E) with each group containing 5 rats. The animals in group A served as control, while groups B, C, D and E served as ...

  11. Effect of modification with nitrocellulose and phenol formaldehyde ...

    African Journals Online (AJOL)

    GRACE

    2006-05-16

    May 16, 2006 ... Processability characteristics and physico-mechanical properties of natural rubber modified with cashew nut shell liquid and cashew nut shell liquid formaldehyde resin. Eur. Poly. J. 38: 163-168. Waldie JM (1983), Oil and Colour Chemists' Association of Association of Australia. Surface Coatings, Vol.1: ...

  12. Analyses of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Tomita Bunchiro; Chung-Yun Hse

    1995-01-01

    The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde unde neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

  13. Analysis on cocondensation of melamine and urea through carbon 13 enriched formaldehyde with carbon 13 nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Bunichiro Tomita; Chung-Yun Hse

    1995-01-01

    The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-urea-formaldehyde (MUF) cocondensed resins were synthesized using the labeling method of 13C enriched formaldehyde udner neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field shifts...

  14. PEMBUATAN AYAKAN MOLEKULER BERBASIS KARBON UNTUK PEMISAHAN N2/O2 DARI PIROLISIS RESIN PHENOL FORMALDEHYDE

    Directory of Open Access Journals (Sweden)

    Imam Prasetyo

    2012-02-01

    Full Text Available Proses pemisahan campuran gas dengan menggunakan carbon molecular sieve (CMS atau ayakan molekuler berbasis karbon merupakan teknologi proses pemisahan yang mulai banyak diterapkan di dalam industri kimia. Dalam penelitian ini, CMS untuk pemisahan N2 dari udara dibuat dari pirolisis bahan polimer sintetis yaitu resin phenol formaldehyde (PF. Prekursor yang berupa resin tersebut dipanaskan dalam retort pada suhu 400-950oC selama 0,5-3 jam yang disertai dengan pengaliran gas N2 ke dalam retort dengan laju 100 mL/jam. Dengan proses pirolisis, atom-atom non-karbon penyusun bahan polimer akan terurai dan menguap sehingga hanya menyisakan arang karbon dengan struktur kerangka atom karbon yang sesuai dengan struktur kerangka dasar rantai polimer. Kemudian karbon hasil prolisis tersebut dipanaskan lebih lanjut pada suhu 750-950oC sambil dialiri gas CO2 selama 1 jam. Pada kondisi ini karbon akan mengalami proses gasifikasi parsial sehingga terbentuk karbon dengan porositas tinggi. Melalui rekayasa proses polimerisasi dan karbonisasi dihasilkan material karbon berpori yang mayoritas porinya adalah mikropori dengan ukuran pori efektif < 2 nm yang dapat dikategorikan sebagai CMS yang dapat dipergunakan untuk memisahkan campuran gas N2-O2.  Pada penelitian ini dihasilkan CMS dengan selektifitas kinetis DN2/DO2 sekitar 3.

  15. Synthesis and Enhanced Formaldehyde-Sensing Properties of In2O3 Hollow Spheres with Thin Shells

    Science.gov (United States)

    Zou, Yanzhao; Wang, Hong; Lai, Xiaoyong; Li, Xuefei; Zhou, Xiaofei; Lin, Guo; Liu, Di; Chen, Jian; Xin, Hong

    2018-03-01

    Uniform-size In2O3 hollow spheres were synthesized using carbon microspheres as sacrificial template and In(NO3)3 as the indium resource. The effects of different solvents on the structure and morphology of as-prepared samples were discussed, and it was found that the shell thickness of In2O3 hollow microspheres could be controlled by changing solvents. The formation mechanism of the In2O3 hollow microspheres was also investigated. The gas-sensing results indicated that all of the as-prepared samples showed high gas-sensing response and excellent selectivity to formaldehyde and In2O3 hollow microspheres had an advantage over the bulk In2O3. Notably, In2O3 hollow microspheres with the shell thickness of 20 nm were fabricated by methanol solution and showed a higher response value of 41 toward 100 ppm HCHO than those of In2O3 hollow microspheres obtained by using other solvents. In2O3 hollow microspheres had good selectivity, high response and fast response-recovery, which made this product a promising gas-sensing material for detecting formaldehyde.

  16. Synthesis and Enhanced Formaldehyde-Sensing Properties of In2O3 Hollow Spheres with Thin Shells

    Science.gov (United States)

    Zou, Yanzhao; Wang, Hong; Lai, Xiaoyong; Li, Xuefei; Zhou, Xiaofei; Lin, Guo; Liu, Di; Chen, Jian; Xin, Hong

    2017-12-01

    Uniform-size In2O3 hollow spheres were synthesized using carbon microspheres as sacrificial template and In(NO3)3 as the indium resource. The effects of different solvents on the structure and morphology of as-prepared samples were discussed, and it was found that the shell thickness of In2O3 hollow microspheres could be controlled by changing solvents. The formation mechanism of the In2O3 hollow microspheres was also investigated. The gas-sensing results indicated that all of the as-prepared samples showed high gas-sensing response and excellent selectivity to formaldehyde and In2O3 hollow microspheres had an advantage over the bulk In2O3. Notably, In2O3 hollow microspheres with the shell thickness of 20 nm were fabricated by methanol solution and showed a higher response value of 41 toward 100 ppm HCHO than those of In2O3 hollow microspheres obtained by using other solvents. In2O3 hollow microspheres had good selectivity, high response and fast response-recovery, which made this product a promising gas-sensing material for detecting formaldehyde.

  17. Kinetic temperature of massive star forming molecular clumps measured with formaldehyde

    Science.gov (United States)

    Tang, X. D.; Henkel, C.; Menten, K. M.; Zheng, X. W.; Esimbek, J.; Zhou, J. J.; Yeh, C. C.; König, C.; Yuan, Y.; He, Y. X.; Li, D. L.

    2017-02-01

    Context. For a general understanding of the physics involved in the star formation process, measurements of physical parameters such as temperature and density are indispensable. The chemical and physical properties of dense clumps of molecular clouds are strongly affected by the kinetic temperature. Therefore, this parameter is essential for a better understanding of the interstellar medium. Formaldehyde, a molecule which traces the entire dense molecular gas, appears to be the most reliable tracer to directly measure the gas kinetic temperature. Aims: We aim to determine the kinetic temperature with spectral lines from formaldehyde and to compare the results with those obtained from ammonia lines for a large number of massive clumps. Methods: Three 218 GHz transitions (JKAKC = 303-202, 322-221, and 321-220) of para-H2CO were observed with the 15 m James Clerk Maxwell Telescope (JCMT) toward 30 massive clumps of the Galactic disk at various stages of high-mass star formation. Using the RADEX non-LTE model, we derive the gas kinetic temperature modeling the measured para-H2CO 322-221/303-202 and 321-220/303-202 ratios. Results: The gas kinetic temperatures derived from the para-H2CO (321-220/303-202) line ratios range from 30 to 61 K with an average of 46 ± 9 K. A comparison of kinetic temperature derived from para-H2CO, NH3, and the dust emission indicates that in many cases para-H2CO traces a similar kinetic temperature to the NH3 (2, 2)/(1, 1) transitions and the dust associated with the HII regions. Distinctly higher temperatures are probed by para-H2CO in the clumps associated with outflows/shocks. Kinetic temperatures obtained from para-H2CO trace turbulence to a higher degree than NH3 (2, 2)/(1, 1) in the massive clumps. The non-thermal velocity dispersions of para-H2CO lines are positively correlated with the gas kinetic temperature. The massive clumps are significantly influenced by supersonic non-thermal motions. The reduced spectra (FITS files) are only

  18. Effects of formaldehyde on mitochondrial dysfunction and apoptosis in SK-N-SH neuroblastoma cells.

    Science.gov (United States)

    Zerin, Tamanna; Kim, Jin-Sun; Gil, Hyo-Wook; Song, Ho-Yeon; Hong, Sae-Yong

    2015-12-01

    Methanol ingestion is neurotoxic in humans due to its metabolites, formaldehyde and formic acid. Here, we compared the cytotoxicity of methanol and its metabolites on different types of cells. While methanol and formic acid did not affect the viability of the cells, formaldehyde (200-800 μg/mL) was strongly cytotoxic in all cell types tested. We investigated the effects of formaldehyde on oxidative stress, mitochondrial respiratory functions, and apoptosis on the sensitive neuronal SK-N-SH cells. Oxidative stress was induced after 2 h of formaldehyde exposure. Formaldehyde at a concentration of 400 μg/mL for 12 h of treatment greatly reduced cellular adenosine triphosphate (ATP) levels. Confocal microscopy indicated that the mitochondrial membrane potential (MMP) was dose-dependently reduced by formaldehyde. A marked and dose-dependent inhibition of mitochondrial respiratory enzymes, viz., NADH dehydrogenase (complex I), cytochrome c oxidase (complex IV), and oxidative stress-sensitive aconitase was also detected following treatment with formaldehyde. Furthermore, formaldehyde caused a concentration-dependent increase in nuclear fragmentation and in the activities of the apoptosis-initiator caspase-9 and apoptosis-effector caspase-3/-7, indicating apoptosis progression. Our data suggests that formaldehyde exerts strong cytotoxicity, at least in part, by inducing oxidative stress, mitochondrial dysfunction, and eventually apoptosis. Changes in mitochondrial respiratory function and oxidative stress by formaldehyde may therefore be critical in methanol-induced toxicity.

  19. Regulation of methylamine and formaldehyde metabolism in Arthrobacter P1. Formaldehyde is the inducing signal for the synthesis of the RuMP cycle enzyme hexulose phosphate synthase

    NARCIS (Netherlands)

    Croes, L.M.; Dijkhuizen, L.

    The inducing potential of formaldehyde on the synthesis of hexulose phosphate synthase, a key enzyme of the RuMP cycle in Arthrobacter P1, was investigated in resting cell suspensions. Induction of this enzyme only occurred at formaldehyde concentrations of 0.5 mM and below. No evidence was obtained

  20. Enzymatic synthesis of C-11 formaldehyde: concise communication

    International Nuclear Information System (INIS)

    Slegers, G.; Lambrecht, R.H.D.; Vandewalle, T.; Meulewaeter, L.; Vandecasteele, C.

    1984-01-01

    An enzymatic synthesis of C-11 formaldehyde from C-11 methanol is presented, with immobilized alcohol oxidase and catalase: a rapid, simple procedure, with a high and reproducible yield. Carbon-11 methanol is oxidized to C-11 formaldehyde by passage over a column on which the enzymes alcohol oxidase and catalase are immobilized. The catalase increases reaction velocity by recycling the oxygen, and prevents destruction of the alcohol oxidase by eliminating the excess of hydrogen peroxide. The yield of the enzyme-catalyzed oxidation was 80-95%. A specific activity of 400-450 mCi/μmole was obtained at EOB + 20 min. Various immobilization techniques and the optimal reaction conditions of the immobilized enzymes are investigated

  1. Simple, rapid method for the preparation of isotopically labeled formaldehyde

    Science.gov (United States)

    Hooker, Jacob Matthew [Port Jefferson, NY; Schonberger, Matthias [Mains, DE; Schieferstein, Hanno [Aabergen, DE; Fowler, Joanna S [Bellport, NY

    2011-10-04

    Isotopically labeled formaldehyde (*C.sup..sctn.H.sub.2O) is prepared from labeled methyl iodide (*C.sup..sctn.H.sub.3I) by reaction with an oxygen nucleophile having a pendant leaving group. The mild and efficient reaction conditions result in good yields of *C.sup..sctn.H.sub.2O with little or no *C isotopic dilution. The simple, efficient production of .sup.11CH.sub.2O is described. The use of the .sup.11CH.sub.2O for the formation of positron emission tomography tracer compounds is described. The reaction can be incorporated into automated equipment available to radiochemistry laboratories. The isotopically labeled formaldehyde can be used in a variety of reactions to provide radiotracer compounds for imaging studies as well as for scintillation counting and autoradiography.

  2. Molecularly Imprinted Polymer Nanoparticles for Formaldehyde Sensing with QCM

    Directory of Open Access Journals (Sweden)

    Munawar Hussain

    2016-06-01

    Full Text Available Herein, we report on molecularly imprinted polymers (MIPs for detecting formaldehyde vapors in air streams. A copolymer thin film consisting of styrene, methacrylic acid, and ethylene glycol dimethacrylate on quartz crystal microbalance (QCM yielded a detection limit of 500 ppb formaldehyde in dry air. Surprisingly, these MIPs showed specific behavior when tested against a range of volatile organic compounds (VOCs, such as acetaldehyde, methanol, formic acid, and dichloromethane. Despite thus being a suitable receptor in principle, the MIPs were not useful for measurements at 50% humidity due to surface saturation by water. This was overcome by introducing primary amino groups into the polymer via allyl amine and by changing the coating morphology from thin film to nanoparticles. This led to the same limit of detection (500 ppb and selectivity as before, but at the real-life conditions of 50% relative humidity.

  3. Molecularly Imprinted Polymer Nanoparticles for Formaldehyde Sensing with QCM

    Science.gov (United States)

    Hussain, Munawar; Kotova, Kira; Lieberzeit, Peter A.

    2016-01-01

    Herein, we report on molecularly imprinted polymers (MIPs) for detecting formaldehyde vapors in air streams. A copolymer thin film consisting of styrene, methacrylic acid, and ethylene glycol dimethacrylate on quartz crystal microbalance (QCM) yielded a detection limit of 500 ppb formaldehyde in dry air. Surprisingly, these MIPs showed specific behavior when tested against a range of volatile organic compounds (VOCs), such as acetaldehyde, methanol, formic acid, and dichloromethane. Despite thus being a suitable receptor in principle, the MIPs were not useful for measurements at 50% humidity due to surface saturation by water. This was overcome by introducing primary amino groups into the polymer via allyl amine and by changing the coating morphology from thin film to nanoparticles. This led to the same limit of detection (500 ppb) and selectivity as before, but at the real-life conditions of 50% relative humidity. PMID:27376287

  4. Low-density carbonized resorcinol-formaldehyde foams

    International Nuclear Information System (INIS)

    Kong, F.M.; Buckley, S.R.; Giles, C.L. Jr.; Haendler, B.L.; Hair, L.M.; Letts, S.A.; Overturf, G.E. III; Price, C.W.; Cook, R.C.

    1991-01-01

    This report documents research and development on resorcinol- formaldehyde-based foam materials conducted between 1986 and June 1990, when the effort was discontinued. The foams discussed are resorcinol-formaldehyde (RF) foam, carbonized RF (CRF) foam, and two composite foams, a polystyrene/RF (PS/RF) foam and its carbonized derivative (CPR). The RF foams are synthesized by the polycondensation of resorcinol with formaldehyde in a slightly basic solution. Their structure and density depend strongly on the concentration of the sodium carbonate catalyst. The have an interconnected bead structure similar to that of silica aerogels; bead sizes range from 30 to 130 Angstrom, and cell sizes are less than 0.1 μm. We have achieved densities of 16 to 200 mg/cm 3 . The RF foams can be pyrolyzed in an inert atmosphere to form a vitreous carbon foam (CRF), which has a similar microstructure but much higher mechanical strength. The PS/RF foams are obtained by filling the 2- to 3-μm cells of PS foam (a low-density hydrocarbon foam we have developed) with RF. The resultant foams have the outstanding handling and machinability of the PS foam matrix and the small cell size of RF. Pyrolyzing PS/RF foams causes depolymerization and loss of the PS; the resulting CPR foams have a structure similar to the PS foams in which CRF both replicates and fills the PS cells

  5. Formaldehyde, methanol and hydrocarbon emissions from methanol-fueled cars

    International Nuclear Information System (INIS)

    Williams, R.L.; Lipari, F.; Potter, R.A.

    1990-01-01

    Exhaust and evaporative emissions tests were conducted on several methanol- and gasoline-fueled vehicles. Separate samples for chromatographic analysis of formaldehyde, methanol, and individual hydrocarbons were collected in each of the three phases of the driving cycle and in each of the two portions of the evaporative emissions test. One vehicle, equipped with an experimental variable-fuel engine, was tested using methanol/gasoline fuel mixtures of 100, 85, 50, 15, and 0 percent methanol. Combustion-generated hydrocarbons were lowest using methanol fuel, and increased several-fold as the gasoline fraction was increased. Gasoline components in the exhaust increased from zero as the gasoline fraction of the fuel was increased. On the other hand, formaldehyde emissions were several times higher using methanol fuel than they were using gasoline. A dedicated methanol car and the variable-fuel car gave similar emissions patterns when they both were tested using methanol fuel. The organic-carbon composition of the exhaust was 85-90 percent methanol, 5-7 percent formaldehyde, and 3-9 percent hydrocarbons. Several cars that were tested using gasoline emitted similar distributions of hydrocarbons, even through the vehicles represented a broad range of current and developmental engine families and emissions control systems

  6. Fast fluorometric flow injection analysis of formaldehyde in atmospheric water

    Energy Technology Data Exchange (ETDEWEB)

    Dong, S.; Dasgupta, P.K.

    1987-06-01

    Formaldehyde can be determined in aqueous solution at a rate of 45 samples/h with a small sample requirement (100 ..mu..L). The fluorescence of 3,5-diacetyl-1,4-dihydrolutidine formed upon reaction of formaldehyde with ammonium acetate and 2,4-pentanedione (25 s, 95 /sup 0/C) is monitored with a filter fluorometer. The detection limit is 0.1 ..mu..M (3 ..mu..g/L) or 10 pmol of HCHO. The response is linear up to 3.3 ..mu..M (100 ..mu..g/L), the departure from linearity at 0.33 mM is 21%, but high levels are satisfactorily determined with a second-order calibration equation. Interference from S(IV) has been investigated in detail and completely eliminated by addition of H/sub 2/O/sub 2/ before rendering the sample alkaline. There are no effects from commonly occurring metal ions and anions; the method is very selective to formaldehyde compared to other carbonyl compounds. A S(IV)-containing preservative has been formulated for the stabilization of low concentrations of HCHO. Results are presented for fogwater samples. 8 figures, 41 references.

  7. Urea-formaldehyde resins: production, application, and testing

    Science.gov (United States)

    Nuryawan, A.; Risnasari, I.; Sucipto, T.; Heri Iswanto, A.; Rosmala Dewi, R.

    2017-07-01

    Urea-formaldehyde (UF) resin, one of the most important formaldehyde resin adhesives, is a polymeric condensation product of formaldehyde with urea, and being widely used for the manufacture of wood-based composite panels, such as plywood, particleboard, and fiberboard. In spite of its benefits such as fast curing, good performance in the panels (colorless), and lower cost; formaldehyde emission (FE) originated from either UF resin itself or composite products bonded by UF resins is considered a critical drawback as it affects human health particularly in indoor environment. In order to reduce the FE, lowering formaldehyde/urea (F/U) mole ratio in the synthesis of the UF resin was done. In this study, synthesis of UF resins was carried out following the conventional alkaline-acid two-step reaction with a second addition of urea, resulting in F/U mole ratio around 1.0, namely 0.95; 1.05, and 1.15. The UF resins produced were used as binder for particleboard making. The board was manufactured in the laboratory using shaving type particle of Gmelina wood, 8% UF resin based on oven dry particle, and 1% NH4Cl (20%wt) as hardener for the resin. The target of the thickness was 10 mm and the dimension was 25 cm x 25 cm. The resulted particleboard then was evaluated the physical and the mechanical properties by Japanese Industrial Standard (JIS) A 5908 (2003). Further, the resulted particleboard also was used for the mice cage’s wall in order to mimic the real living environment. After four weeks exposure in the cages, the mice then were evaluated their mucous organs as well as their blood. The experiment results were as follows: 1) It was possible to synthesis UF resins with low F/U mole ratio; 2) However, the particleboard bonded UF resins with low F/U mole ratio showed poor properties, particularly on the thickness swelling and modulus of elasticity; 3) There was no significant differences among the mucous organs of the mice after a month exposure FE originated from

  8. Melamine-bridged alkyl resorcinol modified urea - formaldehyde resin for bonding hardwood plywood

    Science.gov (United States)

    Chung-Yun Hse; Mitsuo Higuchi

    2010-01-01

    A powdery product was obtained by the reaction of methylolated melamine with alkyl resorcinols to form melamine-bridged alkyl resorcinols (MARs). The effects of the addition of this powder on the bonding strength and formaldehyde emission of urea–formaldehyde (UF) resins were investigated. Three types of UF resins with a formaldehyde/urea molar ratio of 1.3 synthesized...

  9. Formaldehyde-Induced Genome Instability is Suppressed by an XPF-dependent Pathway

    Science.gov (United States)

    Kumari, Anuradha; Lim, Yun Xin; Newell, Amy Hanlon; Olson, Susan B.; McCullough, Amanda K.

    2011-01-01

    Formaldehyde is a reactive chemical that is commonly used in the production of industrial, laboratory, household, and cosmetic products. The causal association between formaldehyde exposure and increased incidence of cancer led the International Agency for Research on Cancer to classify formaldehyde as a carcinogen. Formaldehyde-induced DNA-protein crosslinks (DPCs) elicit responses involving nucleotide excision repair (NER) and homologous recombination (HR) repair pathways; however, little is known about the cellular and genetic changes that subsequently lead to formaldehyde-induced genotoxic and cytotoxic effects. Herein, investigations of genes that modulate the cytotoxic effects of formaldehyde exposure revealed that of five NER-deficient Chinese Hamster Ovary (CHO) cell lines tested, XPF- and ERCC1-deficient cells were most sensitive to formaldehyde treatment as compared to wild-type cells. Cell cycle analyses revealed that formaldehyde-treated XPF-deficient cells exhibited an immediate G2/M arrest that was associated with altered cell ploidy and apoptosis. Additionally, an elevated number of DNA double-strand breaks (DSBs), chromosomal breaks and radial formation were also observed in XPF-deficient cells following formaldehyde treatment. Formaldehyde-induced DSBs occurred in a replication-dependent, but an XPF-independent manner. However, delayed DSB repair was observed in the absence of XPF function. Collectively, our findings highlight the role of an XPF-dependent pathway in mitigating the sensitivity to formaldehyde-induced DNA damage as evidenced by the increased genomic instability and reduced cell viability in an XPF-deficient background. In addition, centrosome and microtubule abnormalities, as well as enlarged nuclei, caused by formaldehyde exposure are also demonstrated in a repair-proficient cell line. PMID:22186232

  10. Porphinogen Formation from the Co-Oligomerization of Formaldehyde and Pyrrole: Free Energy Pathways.

    Science.gov (United States)

    Kua, Jeremy; Loli, Helen

    2017-10-26

    We have investigated the nonoxidative stepwise co-oligomerization of formaldehyde and pyrrole to form porphinogen using density functional theory calculations that include free energy corrections. While the addition of formaldehyde to the pyrrole nitrogen is kinetically favored, thermodynamics suggest that this reaction is reversible in aqueous solution. The more thermodynamically favorable addition of formaldehyde to the ortho-carbon of pyrrole begins a stepwise process, forming dipyrromethane via an azafulvene intermediate. Subsequent additions of formaldehyde and pyrrole lead to bilanes (linear tetrapyrroles), which favorably cyclize to form porphinogen. Porphinogen is a precursor to porphin, the simplest unsubstituted porphyrin that could have played a role in primitive metabolism at the origin of life.

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

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L; Apte, Michael G.

    2010-10-01

    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.

  12. Fiber-Based Adsorbents Tailored for PLSS Ammonia and Formaldehyde Removal, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of advanced lightweight Trace Contaminant Control (TCC) filters plays an important role in removing ammonia and formaldehyde contaminants?both those...

  13. Inactivation kinetics of formaldehyde on N-acetyl-β-D-glucosaminidase from Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Zhang, Wei-Ni; Bai, Ding-Ping; Lin, Xin-Yu; Chen, Qing-Xi; Huang, Xiao-Hong; Huang, Yi-Fan

    2014-04-01

    Formaldehyde is a widely used sanitizer in aquaculture in China, while the appropriate concentration is not available to be used effectively and without damage to tilapia much less to its reproductive function. N-acetyl-β-D-glucosaminidase (EC 3.2.1.52, NAGase), hydrolyzing the oligomers of N-acetyl-β-D-glucosamine into monomer, is proved to be correlated with reproduction of male animals. In this paper, NAGase from spermary of tilapia was chosen as the material to study the effects of formaldehyde on its activity in order to further investigate the effects of formaldehyde use on tilapia reproduction. The results showed the relationship between the residual enzyme activity and the concentration of formaldehyde was concentration dependent, and the IC50 value was estimated to be 3.2 ± 0.1 %. Appropriate concentration of formaldehyde leaded to competitive reversible inhibition on tilapia NAGase. Moreover, formaldehyde could reduce the thermal and pH stability of the enzyme. The inactivation kinetics of formaldehyde on the enzyme was studied using the kinetic method of substrate reaction. The inactivation model was setup, and the rate constants were determined. The results showed that the inactivation of formaldehyde on tilapia NAGase was a slow, reversible reaction with partially residual activity. The results will give some basis to determine the concentration of formaldehyde used in tilapia culture.

  14. Study of Propylene Glycol, Dimethylformamide and Formaldehyde Vapors Sensors Based on MWCNTs/SnO2 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Zaven Adamyan

    2017-06-01

    Full Text Available We present results of our research works related to the study of thick-film multiwall carbon nanotube/tin oxide nanocomposite sensors of propylene glycol (PG, dimethylformamide (DMF and formaldehyde (FA vapors derived using hydrothermal synthesis and sol-gel methods. Investigations of response/recovery characteristics in the 50-300 oC operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times, are about 200 and 220 oC, respectively. A sensor response dependence on gas concentration in all cases is linear. The minimal propylene glycol and dimethylformamide gas concentrations at which the perceptible signal was registered by us were 13 ppm and 5 ppm, respectively.

  15. Studying the Effect of Deposition Conditions on the Performance and Reliability of MEMS Gas Sensors

    Directory of Open Access Journals (Sweden)

    Walied Moussa

    2007-03-01

    Full Text Available In this paper, the reliability of a micro-electro-mechanical system (MEMS-based gas sensor has been investigated using Three Dimensional (3D coupled multiphysics Finite Element (FE analysis. The coupled field analysis involved a two-way sequential electro- thermal fields coupling and a one-way sequential thermal-structural fields coupling. An automated substructuring code was developed to reduce the computational cost involved in simulating this complicated coupled multiphysics FE analysis by up to 76 percent. The substructured multiphysics model was then used to conduct a parametric study of the MEMS-based gas sensor performance in response to the variations expected in the thermal and mechanical characteristics of thin films layers composing the sensing MEMS device generated at various stages of the microfabrication process. Whenever possible, the appropriate deposition variables were correlated in the current work to the design parameters, with good accuracy, for optimum operation conditions of the gas sensor. This is used to establish a set of design rules, using linear and nonlinear empirical relations, which can be utilized in real-time at the design and development decision-making stages of similar gas sensors to enable the microfabrication of these sensors with reliable operation.

  16. FABRICATION AND PROPERTIES OVERCOATED RESORCINOL-FORMALDEHYDE SHELLS FOR OMEGA EXPERIMENTS

    International Nuclear Information System (INIS)

    NIKROO, A; CZECHOWICZ, D; PAGUIO, R; GREENWOOD, A.L; TAKAGI, M.

    2003-09-01

    OAK-B135 New high gain designs for direct drive ignition on NIF require foam shells. Scaled down versions of these designs are needed for near term experiments on the OMEGA laser facility at the Laboratory Laser Energetics (LLE). These shells need to be about 1 mm in diameter and 50-100 (micro)m wall thickness and densities of 100-250 mg/cc. In addition, a full density permeation seal needs to be deposited for retention of the fill gas at room temperature or the ice at cryogenic temperatures. They have fabricated such shells using Resorcinol-formaldehyde (R/F) as the selected foam material due to its transparency in the optical region. Extensive characterization of the wall uniformity of these shells has been performed. The foam shells have ∼ 5%-6% non-concentricities on the average. A full density permeation seal has been deposited on the R/F shells using two different techniques. In the first technique R/F shells are coated directly with plasma polymer to thicknesses of 3-4 (micro)m. In the second technique, R/F shells are coated with polyvinylphenol, using a chemical interfacial polymerization technique. Data on surface finish and gas retention for R/F shells coated by both methods are provided

  17. Formaldehyde induces rapid glutathione export from viable oligodendroglial OLN-93 cells.

    Science.gov (United States)

    Tulpule, Ketki; Schmidt, Maike M; Boecker, Karolin; Goldbaum, Olaf; Richter-Landsberg, Christiane; Dringen, Ralf

    2012-12-01

    Formaldehyde is a neurotoxic environmental pollutant that can also be produced in the body by certain enzymatic reactions. To test for the potential consequences of an exposure of oligodendrocytes to formaldehyde, we used OLN-93 cells as a model system. Treatment with formaldehyde altered the cellular glutathione (GSH) content of these cells by inducing a rapid time- and concentration-dependent export of GSH. Half-maximal effects were observed for a formaldehyde concentration of about 0.2 mM. While the basal GSH efflux from OLN-93 cells was negligible even when the cellular GSH content was doubled by pre-incubation of the cells with cadmium chloride, the formaldehyde-stimulated export increased almost proportionally to the cellular GSH content. In addition, the stimulated GSH export required the presence of formaldehyde and was almost completely abolished after removal of the aldehyde. Analysis of kinetic parameters of the formaldehyde-induced GSH export revealed similar K(m) and V(max) values of around 100 nmol/mg and 40 nmol/(hmg), respectively, for both OLN-93 cells and cultured astrocytes. The transporter responsible for the formaldehyde-induced GSH export from OLN-93 cells is most likely the multidrug resistance protein 1 (Mrp1), since this transporter is expressed in these cells and since the inhibitor MK571 completely prevented the formaldehyde-induced GSH export. The rapid export of GSH from formaldehyde-treated viable oligodendroglial cells is likely to compromise the cellular antioxidative and detoxification potential which may contribute to the known neurotoxicity of formaldehyde. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Preliminary study: Formaldehyde exposure in laboratories of Sharjah university in UAE.

    Science.gov (United States)

    Ahmed, Hafiz Omer

    2011-01-01

    Laboratory technicians, students, and instructors are at high risk, because they deal with chemicals including formaldehyde. Thus, this preliminary study was conducted to measure the concentration of formaldehyde in the laboratories of the University of Sharjah in UAE. Thirty-two air samples were collected and analyzed for formaldehyde using National Institute for Occupational Safety and Health (NIOSH) method 3500. In this method, formaldehyde reacts with chromotropic acid in the presence of sulfuric acid to form a colored solution. The absorbance of the colored solution is read in spectrophotometer at wavelength 580 nm and is proportional to the quantity of the formaldehyde in the solution. For the anatomy laboratory and in the presence of the covered cadaver, the mean concentration of formaldehyde was found to be 0.100 ppm with a range of 0.095-0.105 ppm. Whereas for the other laboratories, the highest mean concentration of formaldehyde was 0.024 ppm in the general microbiology laboratory and the lowest mean concentration of formaldehyde was 0.001 ppm in the environmental health laboratory. The 8-hour (time-weighted average) concentration of formaldehyde was found to be ranging between 0.0003 ppm in environmental health laboratory and 0.026 ppm in the anatomy laboratory. The highest level of concentration of formaldehyde in the presence of the covered cadaver in anatomy laboratory exceeded the recommended ceiling standard established by USA-NIOSH which is 0.1 ppm, but below the ceiling standard established by American Conference of Governmental Industrial Hygienists which is 0.3 ppm. Thus, it is recommended that formaldehyde levels should be measured periodically specially during the dissection in the anatomy laboratory, and local exhaust ventilation system should be installed and personal protective equipment such as safety glass and gloves should be available and be used to prevent direct skin or eye contact.

  19. Phenol-Formaldehyde Resin-Based Carbons for CO2 Separation at Sub-Atmospheric Pressures

    Directory of Open Access Journals (Sweden)

    Noelia Álvarez-Gutiérrez

    2016-03-01

    Full Text Available The challenge of developing effective separation and purification technologies that leave much smaller energy footprints is greater for carbon dioxide (CO2 than for other gases. In addition to its involvement in climate change, CO2 is present as an impurity in biogas and bio-hydrogen (biological production by dark fermentation, in post-combustion processes (flue gas, CO2-N2 and many other gas streams. Selected phenol-formaldehyde resin-based activated carbons prepared in our laboratory have been evaluated under static conditions (adsorption isotherms as potential adsorbents for CO2 separation at sub-atmospheric pressures, i.e., in post-combustion processes or from biogas and bio-hydrogen streams. CO2, H2, N2, and CH4 adsorption isotherms at 25 °C and up to 100 kPa were obtained using a volumetric equipment and were correlated by applying the Sips model. Adsorption equilibrium was then predicted for multicomponent gas mixtures by extending the multicomponent Sips model and the Ideal Adsorbed Solution Theory (IAST in conjunction with the Sips model. The CO2 uptakes of the resin-derived carbons from CO2-CH4, CO2-H2, and CO2-N2 at atmospheric pressure were greater than those of the reference commercial carbon (Calgon BPL. The performance of the resin-derived carbons in terms of equilibrium of adsorption seems therefore relevant to CO2 separation in post-combustion (flue gas, CO2-N2 and in hydrogen fermentation (CO2-H2, CO2-CH4.

  20. NMR studies of proton exchange kinetics in aqueous formaldehyde solutions.

    Science.gov (United States)

    Rivlin, Michal; Eliav, Uzi; Navon, Gil

    2014-05-01

    Aqueous solutions of formaldehyde, formalin, are commonly used for tissue fixation and preservation. Treatment with formalin is known to shorten the tissue transverse relaxation time T2. Part of this shortening is due to the effect of formalin on the water T2. In the present work we show that the shortening of water T2 is a result of proton exchange between water and the major constituent of aqueous solutions of formaldehyde, methylene glycol. We report the observation of the signal of the hydroxyl protons of methylene glycol at 2ppm to high frequency of the water signal that can be seen at low temperatures and at pH range of 6.0±1.5 and, at conditions where it cannot be observed by the single pulse experiment, it can be detected indirectly through the water signal by the chemical exchange saturation transfer (CEST) experiment. The above finding made it possible to obtain the exchange rate between the hydroxyl protons of the methylene glycol and water in aqueous formaldehyde solutions, either using the dispersion of the spin-lattice relaxation rate in the rotating frame (1/T1ρ) or, at the slow exchange regime, from the line width hydroxyl protons of methylene glycol. The exchange rate was ∼10(4)s(-1) at pH 7.4 and 37°C, the activation energy, 50.2kJ/mol and its pH dependence at 1.1°C was fitted to: k (s(-1))=520+6.5×10(7)[H(+)]+3.0×10(9)[OH(-)]. Copyright © 2014. Published by Elsevier Inc.

  1. Rotational spectrum of formaldehyde reinvestigated using a photomixing THz synthesizer

    Science.gov (United States)

    Eliet, Sophie; Cuisset, Arnaud; Guinet, Mickaël; Hindle, Francis; Mouret, Gaël; Bocquet, Robin; Demaison, Jean

    2012-09-01

    Approximately 60 pure rotational frequency transitions of formaldehyde in its ground state have been measured with sub-MHz uncertainty in the 0.7-1.8 THz frequency range using a photomixing THz synthesizer locked onto a frequency comb. The frequencies associated with previous submillimeter and infrared data have been included in a fit providing a new set of improved molecular parameters. The assignment of each line was checked using the usual statistical diagnostics. Finally, the ability of the continuous-wave spectrometer coupled to a multipass-cell to measure THz rotational transitions of H2CO in the 31, 41 and 61 vibrational states was demonstrated.

  2. Separation and characterisation of caprolactam-formaldehyde reaction products.

    Science.gov (United States)

    Normand, Florence C; Goodall, David M; Duckett, Simon B; van Tol, Maurits F H; Nusselder, Jan-Jaap H

    2002-10-01

    Methylolation and condensation products formed in caprolactam-formaldehyde reaction mixtures have been identified using nuclear magnetic resonance (NMR) and mass spectrometry (MS). Previously unreported side-products were also detected. All of the reaction products were separated by micellar electrokinetic chromatography (MEKC) and high performance liquid chromatography (HPLC), and the separation parameters, such as efficiency and distribution constants, obtained in the two techniques were compared. For quantification, the response factors for the monomers were determined using standard calibration and hydrolysis, whilst those for the condensation products were deduced from the values of the monomers. The accurate determination of the response factors was confirmed by checking the mass balance of a known mixture.

  3. 40 CFR 721.10189 - Fatty acids, tall-oil, reaction products with (butoxymethyl) oxirane formaldehyde-phenol polymer...

    Science.gov (United States)

    2010-07-01

    ... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...-phenol polymer glycidyl ether, morpholinepropanamine, propylene glycol diamine and aliphatic polyamine, N... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...

  4. Investigation of physical, mechanical properties and formaldehyde emission of medium density fiberboard manufactured from urea formaldehyde resin reinforced with nanocrystalline cellulose

    Directory of Open Access Journals (Sweden)

    Hossein Khanjanzadeh

    2017-08-01

    Full Text Available The purpose of this study was to evaluate the physico-mechanical properties and formaldehyde emission of medium density fiberboard (MDF made from modified urea formaldehyde resin. In this study, nanocrystalline cellulose (NCC (0, 0.5, 1, 1.5 and 2 percent based on the dry weight of resin was applied to modify urea formaldehyde resin. The results of mechanical properties indicated that MOR and IB of the MDF panels significantly increased as the NCC incorporated into the UF adhesive up to 1%wt. However, further increment in the NCC content (1.5 and 2 wt% decreased the MOR and IB of the panels. Water absorption and thickness swelling after 2 h were significantly increased when the NCC content increased from 1% to 2%, but no significant differences were observed between the panels after 24 h. Also, the formaldehyde emission significantly decreased with increasing the amount of nanocrystalline cellulose.

  5. Determination of formaldehyde in frozen fish with formaldehyde dehydrogenase using a flow injection system with an incorporated gel-filtration chromatrography column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ell

    1996-01-01

    A flow injection analysis (FIA) system for determination of formaldehyde in frozen fish products is described. The system provides a rapid and selective determination of formaldehyde in aqueous fish extracts by the combination of a deproteinization procedure and a stopped-now enzymatic approach...... in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...... and less affected by interferences. The limit of detection for the proposed method is 2.5 mg/l of formaldehyde. The sampling frequency is about 10 determinations per hour....

  6. Determination of Formaldehyde in Frozen Fish with Formaldehyde Dehydrogenase Using a Flow Injection System with an Incorporated Gel-filtration Chromatography Column

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard

    1996-01-01

    A flow injection analysis (FIA) system for determination of formaldehyde in frozen fish products is described. The system provides a rapid and selective determination of formaldehyde in aqueous fish extracts by the combination of a deproteinization procedure and a stopped-flow enzymatic approach...... in a FIA system. The FIA system is furnished with a gel-filtration chromatography column for on-line removal of the proteins from the extract before the enzymatic analysis is performed. Compared with the standard methods for determination of formaldehyde in fish products the present method is much faster...... and less affected by interferences. The limit of detection for the proposed method is 2.5 mg/l of formaldehyde. The sampling frequency is about 10 determinations per hour....

  7. Solid phase microextraction method development for measuring Henry's Law constants of formaldehyde in aqueous solutions

    Science.gov (United States)

    Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its existence in a wide range of products and its adverse health effects. The air-water partitioning behavior of volatile organic compounds (VOCs) such as formaldehyde is an important process th...

  8. Preparation and Characterization of Novolak Phenol Formaldehyde Resin from Liquefied Brown-Rotted Wood

    Science.gov (United States)

    Gai-Yun Li; Chung-Yun Hse; Te-Fu Qin

    2012-01-01

    The brown-rotted wood was liquefied in phenol with phosphoric acid as catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood-based phenol formaldehyde resin (LWPF). The results showed that brown-rotted wood could be more easily liquefied than sound wood in phenol. The residue content of liquefied wood decreased...

  9. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    ... chemiresistive method for various concentrations of formaldehyde vapour at room temperature (∼ 30 °C). For 0.5 ppm of formaldehyde vapour, the film shows a response and recovery time of 36 and 1 s, respectively. The vapour sensing properties of the cerium oxide film in mixed environment were studied and reported.

  10. Developing a Reference Material for Diffusion-Controlled Formaldehyde Emissions Testing

    Science.gov (United States)

    Emissions of formaldehyde from building materials can contaminate indoor air and create significant risks to human health. The need to control formaldehyde emissions from indoor materials is made more urgent by the prevailing drive to improve building energy by decreasing ventil...

  11. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    Administrator

    The occupational safety and health administration (OSHA) has adopted the permissible exposure level (PEL) of. 0∙75 ppm. However, formaldehyde is also a clinically important vapour observed in the human exhaled breath due to imbalance in pulmonary organ system (Poli et al. 2010). The formaldehyde analysis in the ...

  12. Influence of indoor formaldehyde pollution on respiratory system health in the urban area of Shenyang, China.

    Science.gov (United States)

    Zhai, L; Zhao, J; Xu, B; Deng, Y; Xu, Z

    2013-03-01

    The decoration of interior spaces can lead to dangerous levels of indoor formaldehyde pollution. Exposure to indoor air pollution may be responsible for nearly 2 million deaths per year in developing countries. To assess the prevalence of indoor formaldehyde pollution caused by decoration and resultant respiratory system symptoms exhibited in exposed adults and children, due to indoor formaldehyde pollution caused by decoration. Survey sites were chosen and indoor formaldehyde concentrations determined according to the standard of formaldehyde in GB50325-2001. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjusting for potential confounders for this survey. Formaldehyde concentration was above the standard in 64% of Shenyang City. Some adults surveyed complained of common respiratory system disorders, including coughing (11.8%), nasal irritation (39.2%), Heterosmia (14.51%), and throat irritation (25.27%); 12% of children suffered from asthma. The analysis identified formaldehyde pollution and ventilation frequency as risk factors for respiratory system disorders in both adults (OR=2.603, [95% CI: 1.770-3.828], OR=1.604, [95% CI: 1.146-2.244], respectively) and children (OR=4.250, [2.064-8.753], OR=1.831, [1.006-3.333], respectively). The prevalence of common respiratory system disorders was related both to formaldehyde pollution and insufficient ventilation after decorating.

  13. Formaldehyde exposure induces autophagy in testicular tissues of adult male rats.

    Science.gov (United States)

    Han, Shui-Ping; Zhou, Dang-Xia; Lin, Pu; Qin, Zhen; An, Lu; Zheng, Lie-Rui; Lei, Li

    2015-03-01

    Formaldehyde, a ubiquitous environmental pollutant, has long been suspected of causing adverse male reproductive effects. However, the molecular and cellular mechanisms underlying this phenomenon remain elusive. The overall aim of this study is to clarify the role of autophagy in male reproductive injuries induced by formaldehyde exposure, by which we can further understand the molecular mechanism of spermatogenesis and develop new targets for prevention and treatment of male infertility. In this study, electron microscopy, Western blot, and RT-PCR analysis were used to detect autophagy in testicular tissues. Moreover, testicular weights, histopathology, and morphometry were used to evaluate the reproductive injuries of formaldehyde exposure. We found that formaldehyde exposure-induced autophagy in testicular tissues was dose dependent. Increasing autophagosomes in spermatogenetic cells was observed by electron microscopy in formaldehyde exposure group. In addition, RT-PCR and Western blot analysis showed the transcription levels of the LC3-II, as well as the conversion from LC3-I to LC3-II, an indicator of autophagy, significantly increased in testicular tissue of formaldehyde exposure group in a dose dependent manner when compared with those in control group. Furthermore, the alterations of autophage were basically consistent with the changes in testicular weight and morphologic findings. In summary, formaldehyde exposure triggered autophagy, and autophagy may be a scathing factor responsible for male reproductive impairment induced by formaldehyde. © 2013 Wiley Periodicals, Inc.

  14. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban Development Regulations Relating to... Body and Frame Construction Requirements § 3280.308 Formaldehyde emission controls for certain wood...

  15. "Greener" hybrid adhesives composed of urea formaldehyde resin and cottonseed meal for wood based composites

    Science.gov (United States)

    Urea formaldehyde (UF) resins are one of the most widely used adhesives in wood based composites. The major concerns of the resin utilization are free formaldehyde release and poor water resistance. As a renewable raw materials, water washed conttonseed meal can be used in wood bonding. To produce “...

  16. Simultaneous bond degradation and bond formation during phenol-formaldehyde curing with wood

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Bonding of wood using phenol–formaldehyde adhesive develops highly durable bonds. Phenol– formaldehyde is believed to form primary bonds with wood cell wall polymers (e.g., lignin). However, it is unclear how this adhesive interacts and bonds to lignin. Through wood solubilisation methodologies, earlywood and latewood bonded assemblies were characterized using two-...

  17. CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

    Science.gov (United States)

    The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

  18. Assessment of The Effect of Formaldehyde Exposure on The Liver in ...

    African Journals Online (AJOL)

    ... effects of formaldehyde is impairment of the synthetic function of the liver in these mortuary workers. The significantly reduced total globulin level suggests that these workers may be at increased risk of suppressed humoral immunity. Key words: Detoxification, formaldehyde exposure, hepatotoxicity, liver synthetic function, ...

  19. 40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

    Science.gov (United States)

    2010-07-01

    ... with a high FF content. 2. Principle 2.1a. The basis for this method is the titration of the...—Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride 1. Scope This method was... method. The sample should contain approximately 0.3 grams free formaldehyde to ensure complete reaction...

  20. Characterization of novolac type liquefied wood/phenol/formaldehyde (LWPF) resin

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2009-01-01

    Novolac type liquefied wood/phenol/formaldehyde (LWPF) resins were synthesized from liquefied wood and formaldehyde. The average molecular weight of the LWPF resin made from the liquefied wood reacted in an atmospheric three neck flask increased with increasing P/W ratio. However, it decreased with increasing phenol/wood ratio when using a sealed Parr reactor. On...

  1. Guinea pig maximization tests with formaldehyde releasers. Results from two laboratories

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Boman, A; Hamann, K

    1984-01-01

    The guinea pig maximization test was used to evaluate the sensitizing potential of formaldehyde and 6 formaldehyde releasers (Forcide 78, Germall 115, Grotan BK, Grotan OX, KM 200 and Preventol D2). The tests were carried out in 2 laboratories (Copenhagen and Stockholm), and although we intended...

  2. Effect of ventilation rate and board loading on formaldehyde concentration : a critical review of the literature

    Science.gov (United States)

    George E. Myers

    1984-01-01

    A critical literature review has been carried out on the influence of ventilation rate (N, hr.-1) and board loading (L, m2/m3) on steady state formaldehyde concentrations (Cs, ppm) resulting from particleboard and plywood emissions. Large differences exist among boards in the extent to which their formaldehyde concentrations change with N or L in laboratory chambers....

  3. A colorimetric agarose gel for formaldehyde measurement based on nanotechnology involving Tollens reaction.

    Science.gov (United States)

    Zeng, Jing-bin; Fan, Shi-guang; Zhao, Cui-ying; Wang, Qian-ru; Zhou, Ting-yao; Chen, Xi; Yan, Zi-feng; Li, Yan-peng; Xing, Wei; Wang, Xu-dong

    2014-08-04

    Gold nanoparticles (Au NPs) coupled with Tollens reagent were used for measuring formaldehyde. Au@Ag core-shell NPs were formed along with distinct color changes from pink to deep yellow. This colorimetric system was further immobilized into an agarose gel, which was used for monitoring of gaseous formaldehyde.

  4. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    Science.gov (United States)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  5. A new system to reduce formaldehyde levels improves safety conditions during gross veterinary anatomy learning.

    Science.gov (United States)

    Nacher, Víctor; Llombart, Cristina; Carretero, Ana; Navarro, Marc; Ysern, Pere; Calero, Sebastián; Fígols, Enric; Ruberte, Jesús

    2007-01-01

    Dissection is a very useful method of learning veterinary anatomy. However, formaldehyde, which is widely used to preserve cadavers, is an irritant, and it has recently been classified as a carcinogen. In 1997, the Instituto Nacional de Seguridad e Higiene en el Trabajo [National Institute of Workplace Security and Hygiene] found that the levels of formaldehyde in our dissection room were above the threshold limit values. Unfortunately, no optimal substitute for formaldehyde is currently available. Therefore, we designed a new ventilation system that combines slow propulsion of fresh air from above the dissection table and rapid aspiration of polluted air from the perimeter. Formaldehyde measurements performed in 2004, after the introduction of this new system into our dissection laboratory, showed a dramatic reduction (about tenfold, or 0.03 ppm). A suitable propelling/aspirating air system successfully reduces the concentration of formaldehyde in the dissection room, significantly improving safety conditions for students, instructors, and technical staff during gross anatomy learning.

  6. Preparation of nano-TiO2/diatomite-based porous ceramics and their photocatalytic kinetics for formaldehyde degradation

    Science.gov (United States)

    Gao, Ru-qin; Sun, Qian; Fang, Zhi; Li, Guo-ting; Jia, Meng-zhe; Hou, Xin-mei

    2018-01-01

    Diatomite-based porous ceramics were adopted as carriers to immobilize nano-TiO2 via a hydrolysis-deposition technique. The thermal degradation of as-prepared composites was investigated using thermogravimetric-differential thermal analysis, and the phase and microstructure were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy. The results indicated that the carriers were encapsulated by nano-TiO2 with a thickness of 300-450 nm. The main crystalline phase of TiO2 calcined at 650°C was anatase, and the average grain size was 8.3 nm. The FT-IR absorption bands at 955.38 cm-1 suggested that new chemical bonds among Ti, O, and Si had formed in the composites. The photocatalytic (PC) activity of the composites was investigated under UV irradiation. Furthermore, the photodegradation kinetics of formaldehyde was investigated using the composites as the cores of an air cleaner. A kinetics study showed that the reaction rate constants of the gas-phase PC reaction of formaldehyde were κ = 0.576 mg·m-3·min-1 and K = 0.048 m3/mg.

  7. A new non-resonant laser-induced fluorescence instrument for the airborne in situ measurement of formaldehyde

    Directory of Open Access Journals (Sweden)

    J. M. St. Clair

    2017-12-01

    Full Text Available A new in situ instrument for gas-phase formaldehyde (HCHO, COmpact Formaldehyde FluorescencE Experiment (COFFEE, is presented. COFFEE utilizes non-resonant laser-induced fluorescence (NR-LIF to measure HCHO, with 300 mW of 40 kHz 355 nm laser output exciting multiple HCHO absorption features. The resulting HCHO fluorescence is collected at 5 ns resolution, and the fluorescence time profile is fit to yield the ambient HCHO mixing ratio. Typical 1σ precision at  ∼  0 pptv HCHO is 150 pptv for 1 s data. The compact instrument was designed to operate with minimal in-flight operator interaction and infrequent maintenance (1–2 times per year. COFFEE fits in the wing pod of the Alpha Jet stationed at the NASA Ames Research Center and has successfully collected HCHO data on 27 flights through 2017 March. The frequent flights, combined with a potentially long-term data set, makes the Alpha Jet a promising platform for validation of satellite-based column HCHO.

  8. Effects of cryogenic temperature on the mechanical and failure characteristics of melamine-urea-formaldehyde adhesive plywood

    Science.gov (United States)

    Kim, Jeong-Hyeon; Choi, Sung-Woong; Park, Doo-Hwan; Park, Seong-Bo; Kim, Seul-Kee; Park, Kwang-Jun; Lee, Jae-Myung

    2018-04-01

    The present study investigates the applicability of melamine-urea-formaldehyde (MUF) resin plywood in cryogenic applications, including liquefied natural gas (LNG) carrier insulation systems. Phenolic-formaldehyde (PF) resin plywood has been extensively used as a structural material in industrial applications. However, many shortcomings of PF resin plywood have been reported, and replacement of PF resin plywood with a new material is necessary to resolve these problems. MUF resin plywood has the advantages of short fabrication time, low veneer cost, and economic feasibility compared to PF resin plywood. However, the mechanical and failure characteristics of MUF resin plywood have not yet been investigated at low temperature ranges. For this reason, adapting MUF resin plywood for cryogenic applications has been difficult, despite the many strong points of the material in engineering aspects. In this study, the effects of cryogenic temperature and thermal treatment on the mechanical characteristics of MUF resin plywood are investigated. The performance of MUF resin plywood is compared with that of PF resin plywood to verify the applicability of the material for use as a structural material in LNG insulation systems. The results demonstrate that MUF resin plywood has mechanical properties comparable with those of PF resin plywood, even at cryogenic conditions.

  9. FORMALDEHYDE AND METHANOL DEUTERATION IN PROTOSTARS: FOSSILS FROM A PAST FAST HIGH-DENSITY PRE-COLLAPSE PHASE

    Energy Technology Data Exchange (ETDEWEB)

    Taquet, V.; Ceccarelli, C.; Kahane, C. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, F-38041 Grenoble (France)

    2012-03-20

    Extremely high deuteration of several molecules has been observed around low-mass protostars for a decade. Among them, formaldehyde and methanol present particularly high deuteration, with observations of abundant doubly and triply deuterated forms. Both species are thought to be mainly formed on interstellar grains during the low-temperature and dense pre-collapse phase by H and D atom additions on the iced CO. We present here a theoretical study of the formaldehyde and methanol deuteration obtained with our gas-grain model, GRAINOBLE. This model takes into account the multilayer nature of the mantle and explores the robustness of the results against the uncertainties of poorly constrained chemical and surface model parameters. The comparison of the model predictions with the observations leads to two major results: (1) the observed high deuteration is obtained during the last phase of the pre-collapse stage, when the density reaches {approx}5 Multiplication-Sign 10{sup 6} cm{sup -3}, and this phase is fast, lasting only several thousands years; and (2) D and H abstraction and substitution reactions are crucial in making up the observed deuteration ratios. This work shows the power of chemical composition as a tool to reconstruct the past history of protostars.

  10. A new non-resonant laser-induced fluorescence instrument for the airborne in situ measurement of formaldehyde

    Science.gov (United States)

    St. Clair, Jason M.; Swanson, Andrew K.; Bailey, Steven A.; Wolfe, Glenn M.; Marrero, Josette E.; Iraci, Laura T.; Hagopian, John G.; Hanisco, Thomas F.

    2017-12-01

    A new in situ instrument for gas-phase formaldehyde (HCHO), COmpact Formaldehyde FluorescencE Experiment (COFFEE), is presented. COFFEE utilizes non-resonant laser-induced fluorescence (NR-LIF) to measure HCHO, with 300 mW of 40 kHz 355 nm laser output exciting multiple HCHO absorption features. The resulting HCHO fluorescence is collected at 5 ns resolution, and the fluorescence time profile is fit to yield the ambient HCHO mixing ratio. Typical 1σ precision at ˜ 0 pptv HCHO is 150 pptv for 1 s data. The compact instrument was designed to operate with minimal in-flight operator interaction and infrequent maintenance (1-2 times per year). COFFEE fits in the wing pod of the Alpha Jet stationed at the NASA Ames Research Center and has successfully collected HCHO data on 27 flights through 2017 March. The frequent flights, combined with a potentially long-term data set, makes the Alpha Jet a promising platform for validation of satellite-based column HCHO.

  11. Analysis of cocondensation of melamine and urea through carbon 13 enriched formaldehyde with C-13 nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Bunichiro Tomita; Chung-Yun Hse

    1995-01-01

    The urea-formaldehyde (UF) resins, melamine-formaldehyde (MF) resins, and melamine-ureaformaldehyde (MUF) cocondensed resins were synthesized using the labeling method with 13C enriched formaldehyde under neutral conditions and their 13C-NMR (nuclear magnetic resonance) spectra were analyzed. The remarkable down-field...

  12. 40 CFR 721.10190 - Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with aliphatic... Formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4-methyl-2-pentanone (generic... identified generically as formaldehyde, polymer with aliphatic diamine and phenol, reaction products with 4...

  13. 40 CFR 721.5560 - Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz[c...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with... Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6... identified as formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz...

  14. 40 CFR 721.3830 - Formaldehyde, reaction products with an alkylated phenol and an aliphatic amine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3830 Formaldehyde, reaction... new uses subject to reporting. (1) The chemical substance identified generically as Formaldehyde...

  15. Ayty: a New Line-List for Hot Formaldehyde

    Science.gov (United States)

    Al-Refaie, Ahmed Faris; Yurchenko, Sergei N.; Tennyson, Jonathan; Yachmenev, Andrey

    2015-06-01

    The ExoMol [1] project aims at providing spectroscopic data for key molecules that can be used to characterize the atmospheres of exoplanets and cool stars. Formaldehyde (H2CO) is of growing importance in studying and modelling terrestrial atmospheric chemistry and dynamics. It also has relevance in astrophysical phenomena that include interstellar medium abundance, proto-planetary and cometary ice chemistry and masers from extra-galactic sources. However there gaps in currently available absolute intensities and a lack of higher rotational excitations that makes it unfeasible to accurately model high temperature systems such as hot Jupiters. Here we present AYTY [2], a new line list for formaldehyde applicable to temperatures up to 1500 K. AYTY contains almost 10 million states reaching rotational excitations up to J=70 and over 10 billion transitions at up to 10 000 cm-1. The line list was computed using the variational ro-vibrational solver TROVE with a refined ab-initio potential energy surface and dipole moment surface. J.~Tennyson and S.~N. Yurchenko MNRAS, 425:21--33, 2012. A.~F. Al-Refaie, S.~N. Yurchenko, A.~Yachmenev, and J.~Tennyson MNRAS, 2015.

  16. Formaldehyde and Epigenetic Alterations: MicroRNA Changes in the Nasal Epithelium of Nonhuman Primates

    Science.gov (United States)

    Rager, Julia E.; Moeller, Benjamin C.; Doyle-Eisele, Melanie; Kracko, Dean; Swenberg, James A.

    2013-01-01

    Background: Formaldehyde is an air pollutant present in both indoor and outdoor atmospheres. Because of its ubiquitous nature, it is imperative to understand the mechanisms underlying formaldehyde-induced toxicity and carcinogenicity. MicroRNAs (miRNAs) can influence disease caused by environmental exposures, yet miRNAs are understudied in relation to formaldehyde. Our previous investigation demonstrated that formaldehyde exposure in human lung cells caused disruptions in miRNA expression profiles in vitro. Objectives: Using an in vivo model, we set out to test the hypothesis that formaldehyde inhalation exposure significantly alters miRNA expression profiles within the nasal epithelium of nonhuman primates. Methods: Cynomolgus macaques were exposed by inhalation to approximately 0, 2, or 6 ppm formaldehyde for 6 hr/day for 2 consecutive days. Small RNAs were extracted from nasal samples and assessed for genome-wide miRNA expression levels. Transcriptional targets of formaldehyde-altered miRNAs were computationally predicted, analyzed at the systems level, and assessed using real-time reverse transcriptase polymerase chain reaction (RT-PCR). Results: Expression analysis revealed that 3 and 13 miRNAs were dysregulated in response to 2 and 6 ppm formaldehyde, respectively. Transcriptional targets of the miRNA with the greatest increase (miR-125b) and decrease (miR-142-3p) in expression were predicted and analyzed at the systems level. Enrichment was identified for miR-125b targeting genes involved in apoptosis signaling. The apoptosis-related targets were functionally tested using RT-PCR, where all targets showed decreased expression in formaldehyde-exposed samples. Conclusions: Formaldehyde exposure significantly disrupts miRNA expression profiles within the nasal epithelium, and these alterations likely influence apoptosis signaling. PMID:23322811

  17. Experimental setup and analytical methods for the non-invasive determination of volatile organic compounds, formaldehyde and NOx in exhaled human breath

    International Nuclear Information System (INIS)

    Riess, Ulrich; Tegtbur, Uwe; Fauck, Christian; Fuhrmann, Frank; Markewitz, Doreen; Salthammer, Tunga

    2010-01-01

    Different analytical devices were tested and evaluated for their suitability of breath gas analysis by examining the physiological parameters and chemical substances in the exhaled breath of ten healthy probands during light cycling in dependence of methanol-rich nutrition. The probands exercised under normal breathing conditions on a bicycle ergometer. Breath air was exhaled into a glass cylinder and collected under steady-state conditions. Non-invasively measured parameters were pulse rate, breath frequency, temperature, relative humidity, NO x , total volatile organic compounds (TVOC PAS ), carbon dioxide (CO 2 ), formaldehyde, methanol, acetaldehyde, acetone, isoprene and volatile organic compounds (VOCs). Methanol rich food and beverages strongly influenced the concentration of methanol and other organic substances in human breath. On the other hand, nutrition and smoking had no clear effect on the physical conditions of the probands. The proton transfer reaction mass spectrometry (PTR-MS) method was found to be very suitable for the analysis of breath gas but the m/z 31, if assigned to formaldehyde, is sensitive to interferences. The time vs. concentration curves of nitric oxide showed sudden peaks up to 120 ppb in most of the measurements. In one case a strong interference of the NO x signal was observed. The time resolved analysis of exhaled breath gas is of high capability and significance for different applications if reliable analytical techniques are used. Some compounds like nitric oxide (NO), methanol, different VOCs as well as sum parameters like TVOC PAS are especially suitable as markers. Formaldehyde, which is rapidly metabolized in the human body, could be measured reliably as a trace component by the acetylacetone (acac) method but not by PTR-MS.

  18. Experimental setup and analytical methods for the non-invasive determination of volatile organic compounds, formaldehyde and NO{sub x} in exhaled human breath

    Energy Technology Data Exchange (ETDEWEB)

    Riess, Ulrich; Tegtbur, Uwe [Hannover Medical School, Sports Physiology and Sports Medicine, Carl-Neuberg-Str. 1, 30625 Hannover (Germany); Fauck, Christian; Fuhrmann, Frank; Markewitz, Doreen [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54 E, 38108 Braunschweig (Germany); Salthammer, Tunga, E-mail: tunga.salthammer@wki.fraunhofer.de [Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Bienroder Weg 54 E, 38108 Braunschweig (Germany)

    2010-06-11

    Different analytical devices were tested and evaluated for their suitability of breath gas analysis by examining the physiological parameters and chemical substances in the exhaled breath of ten healthy probands during light cycling in dependence of methanol-rich nutrition. The probands exercised under normal breathing conditions on a bicycle ergometer. Breath air was exhaled into a glass cylinder and collected under steady-state conditions. Non-invasively measured parameters were pulse rate, breath frequency, temperature, relative humidity, NO{sub x}, total volatile organic compounds (TVOC{sub PAS}), carbon dioxide (CO{sub 2}), formaldehyde, methanol, acetaldehyde, acetone, isoprene and volatile organic compounds (VOCs). Methanol rich food and beverages strongly influenced the concentration of methanol and other organic substances in human breath. On the other hand, nutrition and smoking had no clear effect on the physical conditions of the probands. The proton transfer reaction mass spectrometry (PTR-MS) method was found to be very suitable for the analysis of breath gas but the m/z 31, if assigned to formaldehyde, is sensitive to interferences. The time vs. concentration curves of nitric oxide showed sudden peaks up to 120 ppb in most of the measurements. In one case a strong interference of the NO{sub x} signal was observed. The time resolved analysis of exhaled breath gas is of high capability and significance for different applications if reliable analytical techniques are used. Some compounds like nitric oxide (NO), methanol, different VOCs as well as sum parameters like TVOC{sub PAS} are especially suitable as markers. Formaldehyde, which is rapidly metabolized in the human body, could be measured reliably as a trace component by the acetylacetone (acac) method but not by PTR-MS.

  19. Role of Moving Bed Biofilm Reactor and Sequencing Batch Reactor in Biological Degradation of Formaldehyde Wastewater

    Directory of Open Access Journals (Sweden)

    B. Ayati

    2011-10-01

    Full Text Available Nowadays formaldehyde is used as raw material in many industries. It has also disinfection applications in some public places. Due to its toxicity for microorganisms, chemical or anaerobic biological methods are applied for treating wastewater containing formaldehyde.In this research, formaldehyde removal efficiencies of aerobic biological treatment systems including moving bed biofilm (MMBR and sequencing batch reactors (SBR were investigated. During all experiments, the efficiency of SBR was more than MBBR, but the difference was not significant statistically. According to the results, the best efficiencies were obtained for influent formaldehyde COD of 200 mg/L in MBBR and SBR which were 93% and 99.4%, respectively. The systems were also capable to treat higher formaldehyde concentrations (up to 2500 mg/L with lower removal efficiency. The reaction kinetics followed the Stover-Kincannon second order model. The gram-positive and gram-negative bacillus and coccus as well as the gram-positive binary bacillus were found to be the most dominant species. The results of 13C-NMR analysis have shown that formaldehyde and urea were converted into N-{[(aminocarbonyl amino] methyl}urea and the residual formaldehyde was polymerized at room temperature.

  20. Determination of carbonyl compounds (acetaldehyde and formaldehyde in polyethylene terephthalate containers designated for water conservation

    Directory of Open Access Journals (Sweden)

    Redžepović Azra S.

    2012-01-01

    Full Text Available Polyethylene terephthalate (PET has in the last several years become the main packaging material for many food products, particularly carbonated beverages and bottled water, as well as for products of chemical industry (packaging of various hygiene maintenance agents, pesticides, solvents, etc.. The strength and permeability properties of PET are very good for packaging of beverages, its resistance to chemicals is high and it has a high degree of transparency. Acetaldehyde and formaldehyde are formed during the thermoforming of PET containers. After cooling, acetaldehyde and formaldehyde remain trapped in the walls of a PET bottle and may migrate into the water after filling and storage. Since there are no migration tests in Serbia prescribed for the determination of acetaldehyde and formaldehyde, the purpose of the paper is to test the quantitative contents of carbonyl compounds (acetaldehyde and formaldehyde in PET containers of different volumes, made by various manufacturers of bottled mineral carbonated and noncarbonated water, and exposed to different temperatures. In this study, the migration of acetaldehyde and formaldehyde from PET bottles into mineral carbonated and noncarbonated water was determined by high performance liquid chromatography. Taking into consideration that formaldehyde and acetaldehyde have no UV active or fluorescent group, the chromatography shall be preceded by derivatization in a closed system (due to a low boiling point of acetaldehyde and formaldehyde, which shall transform carbonyl compounds into UV active compounds.

  1. Therapeutic role of curcumin in oxidative DNA damage caused by formaldehyde.

    Science.gov (United States)

    Ciftci, Gulay; Aksoy, Abdurrahman; Cenesiz, Sena; Sogut, Mehtap Unlu; Yarim, Gul Fatma; Nisbet, Cevat; Guvenc, Dilek; Ertekin, Ali

    2015-05-01

    Formaldehyde is a common environmental contaminant that causes oxidative DNA damage in cells by increasing the production of reactive oxygen species. The aim of this study was to investigate the amount of 8-hydroxy-deoxyguanosine (8-OhdG), tumor protein 53(TP53), beta-amyloid[Aß(1-42), Aß (1-40)], total antioxidant capacity (TAC) and malondialdehyde (MDA) and the therapeutic role of curcumin in rat cells with oxidative DNA damage caused by formaldehyde. The control group was given physiological saline for 15 days (i.p.) and the second group was given 37% formaldehyde (i.p.) at a dose of 9 mg/kg group every other day. The third group was given 9 mg/kg formaldehyde (i.p.) every other day and treated therapeutically with 100 mg/kg curcumin every day by gavage. At the end of the trial period, urine, blood, and brain tissue was collected from the rats. The levels of MDA in sera were increased and the TAC, TP53, and Aß (1-40) levels were reduced in the formaldehyde-treated group with respect to the control group (pformaldehyde-treated group and reduced after treatment with curcumin (P formaldehyde-treated group (P  0.05). In conclusion, the oxidative stress caused by formaldehyde exposure was reduced with the application of curcumin. © 2015 Wiley Periodicals, Inc.

  2. Plasma Level Formaldehyde in Children Receiving Pulpotomy Treatment under General Anesthesia.

    Science.gov (United States)

    Bagrizan, Majid; Pourgolshani, Pouya; Hosseinpour, Sepanta; Jalalpour, Golnoush; Shahrestani, Mostafa Zahmatkesh

    Formocresol has long been used by dentists for pulpotomy of primary teeth. Due to some concerns regarding its possible carcinogenicity, formocresol has been the topic of numerous studies. This study sought to assess the changes in plasma level of formaldehyde of children after receiving pulpotomy under general anesthesia. Twenty-five children between 2-6 years requiring dental treatments under general anesthesia were studied. Blood samples were taken of children before and after the procedure. Plasma level of formaldehyde was measured using high performance liquid chromatography (HPLC). A total of 106 pulpotomy treatments were performed in 25 children using 126 cotton pellets dipped in formocresol. An increase and a decrease in plasma level of formaldehyde were noted in 5 (20%) and 20 (80%) children, respectively post-operatively compared to baseline. The t-test showed no significant difference in plasma level of formaldehyde pre- and postoperatively (P=0.12). the plasma level of formaldehyde in children who had higher levels of formaldehyde prior to the operation was also higher than that of others after the operation and this association was statistically significant (P=0.001, r=0.64). The results showed no significant change in the mean plasma level of formaldehyde in children who received pulpotomy under general anesthesia compared to its baseline value.

  3. The Roles of Formaldehyde Exposure and Oxidative Stress in Fetal Growth in the Second Trimester.

    Science.gov (United States)

    Amiri, Azita; Turner-Henson, Anne

    To examine the relationship between formaldehyde exposure and fetal growth in the second trimester and the potential mediating role of oxidative stress in this relationship. A cross-sectional study was conducted. The participants were recruited from one university-related clinic and two private obstetrics and gynecology offices in the Southeastern United States. A convenience sample of 140 healthy pregnant women in the second trimester of pregnancy was enrolled from November 2013 through June 2014. Formaldehyde exposure was measured via vapor monitors worn by the participants for 24 hours. One-time urine samples were collected during a routine prenatal visit to measure the level of 15-isoprostane F 2t and cotinine as biomarkers of oxidative stress and tobacco smoking, respectively. Urine creatinine was measured to standardize the cotinine and 15-isoprostane F 2t levels. Eighty-eight participants (63%) returned their formaldehyde monitors. The linear regression model showed that the dichotomized level of formaldehyde exposure (0.03 ppm) was a significant predictor of biparietal diameter percentile after controlling for maternal race (p formaldehyde exposure and biparietal diameter was not confirmed. A relationship was found between formaldehyde exposure and biparietal diameter in the second trimester. Although further research is necessary to confirm the results of this study, nurses may consider advising pregnant women to limit their exposure to formaldehyde during pregnancy. Copyright © 2017 AWHONN, the Association of Women’s Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  4. Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde.

    Science.gov (United States)

    Niu, Song; Yan, Hongxia

    2015-04-28

    Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by (13)C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Technical Note: Intercomparison of formaldehyde measurements at the atmosphere simulation chamber SAPHIR

    Directory of Open Access Journals (Sweden)

    A. Wisthaler

    2008-04-01

    Full Text Available The atmosphere simulation chamber SAPHIR at the Research Centre Jülich was used to test the suitability of state-of-the-art analytical instruments for the measurement of gas-phase formaldehyde (HCHO in air. Five analyzers based on four different sensing principles were deployed: a differential optical absorption spectrometer (DOAS, cartridges for 2,4-dinitro-phenyl-hydrazine (DNPH derivatization followed by off-line high pressure liquid chromatography (HPLC analysis, two different types of commercially available wet chemical sensors based on Hantzsch fluorimetry, and a proton-transfer-reaction mass spectrometer (PTR-MS. A new optimized mode of operation was used for the PTR-MS instrument which significantly enhanced its performance for online HCHO detection at low absolute humidities.

    The instruments were challenged with typical ambient levels of HCHO ranging from zero to several ppb. Synthetic air of high purity and particulate-filtered ambient air were used as sample matrices in the atmosphere simulation chamber onto which HCHO was spiked under varying levels of humidity and ozone. Measurements were compared to mixing ratios calculated from the chamber volume and the known amount of HCHO injected into the chamber; measurements were also compared between the different instruments. The formal and blind intercomparison exercise was conducted under the control of an independent referee. A number of analytical problems associated with the experimental set-up and with individual instruments were identified, the overall agreement between the methods was fair.

  6. B{sub 36} borophene as an electronic sensor for formaldehyde: Quantum chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shahbazi Kootenaei, Amirhossein, E-mail: a.kootenaei@gmail.com [Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of); Ansari, Goodarz [Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr (Iran, Islamic Republic of)

    2016-08-06

    Pristine carbon nanotubes and graphene show great sensitivity toward several lethal gases but cannot identify some extremely toxic chemicals such as formaldehyde (HCOH). Recent successful synthesis of all-boron graphene-like sheets attracted strong interest in exploring their possible applications. Herein, we inspected the potential application of B{sub 36} borophene sheet as a sensor for HCOH detection, using density functional theory computations. Different theoretical levels including B97D and Minnesota 06 functionals with different basis sets were employed. It was predicted that the electrical conductivity of B{sub 36} borophene significantly increases at the presence of HCOH molecules, thereby generating an electrical signal. The electrical signal is increased by increasing the number of adsorbed HCOH molecules, indicating that this sensor is sensitive to the concentration (or pressure) of HCOH gas. These results suggest that the pristine borophene may be used in the HCOH chemical sensors. - Highlights: • B{sub 36} borophene sheet can be used as a chemical sensor for HCOH detection. • The B{sub 36} is sensitive to the concentration of HCOH. • When the B{sub 36} adsorbs HCOH molecules, it is converted to a p-type semiconductor.

  7. Amperometric Formaldehyde Sensor Based on a Pd Nanocrystal Modified C/Co2P Electrode

    Directory of Open Access Journals (Sweden)

    Huan Wang

    2017-01-01

    Full Text Available Ultrafine Pd nanocrystals were grown on the cobalt phosphide (Co2P decorated Vulcan XC-72 carbon (C/Co2P, which is realized by first implementing the corresponding metal precursor and then the further chemical reduction process. The as-synthesized C/Co2P/Pd composite was further constructed to form a gas permeable electrode. This electrode can be applied for formaldehyde (HCHO detection. The results demonstrate that the Co2P nanocrystal can significantly improve the sensing performance of the C/Co2P/Pd electrode for catalytic oxidation of HCHO, which is considered to be attributed to the effective electron transfer from Co2P to Pd in the C/Co2P/Pd composites. Furthermore, the assembled C/Co2P/Pd sensor exhibits high sensitivity of 617 nA/ppm and good selectivity toward various interfering gases such as NO2, NO, SO2, CO2, and CO. It also shows the excellent linear response that the correlation coefficient is 0.994 in the concentration range of 1–10 ppm. Therefore, the proposed cost-effective C/Co2P/Pd nanocomposite, which owns advantages such as high activity and good stability, has the potential to be applied as an effective electrocatalyst for amperometric HCHO detection.

  8. Standard formaldehyde source for chamber testing of material emissions: model development, experimental evaluation, and impacts of environmental factors.

    Science.gov (United States)

    Wei, Wenjuan; Howard-Reed, Cynthia; Persily, Andrew; Zhang, Yinping

    2013-07-16

    Formaldehyde, which is recognized as a harmful indoor air pollutant for human health, is emitted mainly from urea-formaldehyde resin in wood products. Chamber tests are used to evaluate formaldehyde emission rates from these products. However, there is no available formaldehyde standard reference emission source to assess the performance of chamber testing systems. In this work, a LIFE (liquid-inner tube diffusion-film-emission) formaldehyde reference is described. The formaldehyde source consists of a polytetrafluoroethene (PTFE) tube that holds a formaldehyde-water solution with a concentration of 16 g formaldehyde per 100 mL water, with a thin polydimethylsiloxane (PDMS) film cover. Formaldehyde emission parameters for the PDMS film (diffusion coefficient and partition coefficient) were determined experimentally, thereby enabling the prediction of the formaldehyde emissions from the source for use as a reference value in a chamber. Chamber tests were conducted in a 51 L stainless steel ventilated chamber. The impacts of temperature and relative humidity on the emissions were investigated. Results show the LIFE's chamber test results match those predicted by a mass transfer model. As a result, this formaldehyde source may be used to generate a reference concentration in product emission testing chambers, thereby providing a powerful tool to evaluate the performance of the chamber testing systems.

  9. Quantification of free formaldehyde in carrageenan and processed Eucheuma seaweed using high-performance liquid chromatography.

    Science.gov (United States)

    Hornshøj, Bettina Høj; Kobbelgaard, Sara; Blakemore, William R; Stapelfeldt, Henrik; Bixler, Harris J; Klinger, Markus

    2015-01-01

    In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processed Eucheuma seaweed (PES) of 5 mg kg(-1). Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg(-1) have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg(-1) and a limit of quantification of 0.2 mg kg(-1). Recoveries from samples spiked with known quantities of formaldehyde were 95-107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg(-1)), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg(-1).

  10. The protective effect of geniposide on human neuroblastoma cells in the presence of formaldehyde

    Science.gov (United States)

    2013-01-01

    Background Formaldehyde can induce misfolding and aggregation of Tau protein and β amyloid protein, which are characteristic pathological features of Alzheimer’s disease (AD). An increase in endogenous formaldehyde concentration in the brain is closely related to dementia in aging people. Therefore, the discovery of effective drugs to counteract the adverse impact of formaldehyde on neuronal cells is beneficial for the development of appropriate treatments for age-associated cognitive decline. Methods In this study, we assessed the neuroprotective properties of TongLuoJiuNao (TLJN), a traditional Chinese medicine preparation, against formaldehyde stress in human neuroblastoma cells (SH-SY5Y cell line). The effect of TLJN and its main ingredients (geniposide and ginsenoside Rg1) on cell viability, apoptosis, intracellular antioxidant activity and the expression of apoptotic-related genes in the presence of formaldehyde were monitored. Results Cell counting studies showed that in the presence of TLJN, the viability of formaldehyde-treated SH-SY5Y cells significantly recovered. Laser scanning confocal microscopy revealed that the morphology of formaldehyde-injured cells was rescued by TLJN and geniposide, an effective ingredient of TLJN. Moreover, the inhibitory effect of geniposide on formaldehyde-induced apoptosis was dose-dependent. The activity of intracellular antioxidants (superoxide dismutase and glutathione peroxidase) increased, as did mRNA and protein levels of the antiapoptotic gene Bcl-2 after the addition of geniposide. In contrast, the expression of the apoptotic-related gene - P53, apoptotic executer - caspase 3 and apoptotic initiator - caspase 9 were downregulated after geniposide treatment. Conclusions Our results indicate that geniposide can protect SH-SY5Y cells against formaldehyde stress through modulating the expression of Bcl-2, P53, caspase 3 and caspase 9, and by increasing the activity of intracellular superoxide dismutase and glutathione

  11. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage

    Science.gov (United States)

    Yu, Rui; Lai, Yongquan; Hartwell, Hadley J.; Moeller, Benjamin C.; Doyle-Eisele, Melanie; Kracko, Dean; Bodnar, Wanda M.; Starr, Thomas B.; Swenberg, James A.

    2015-01-01

    Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N2-hydroxymethyl-dG (N2-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N2-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [13CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N2-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency’s Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair. PMID:25904104

  12. Tunneling corrections to unimolecular rate constants, with application to formaldehyde

    International Nuclear Information System (INIS)

    Miller, W.H.

    1979-01-01

    Tunneling corrections to the rate constant for unimolecular reactions in an isolated molecule are treated within the standard transition state (i.e., RRKM) theory of such processes. The microcanonical distribution relevant to the unimolecular case causes tunneling effects to enter in a somewhat more complicated fashion than in the analogous transition-state theory for thermally averaged bimolecular rate constants; e.g., even within the separable approximation they do not enter as simply a multiplicative correction factor. Application of the theoretical expressions to some unimolecular processes (H 2 CO → H 2 + CO, trans-HCOH → H 2 CO) of interest in the collisionless photochemistry of formaldehyde indicates that tunneling effects are quite significant for rates of 10 9 s -1 or slower. Isotope effects are also considered and seen to be quite interesting. 4 figures, 1 table

  13. Studies of Deactivation of Methanol to Formaldehyde Selective Oxidation Catalyst

    DEFF Research Database (Denmark)

    Raun, Kristian Viegaard; Schumann, Max; Høj, Martin

    as the Formox process [1]. The average lifetime of the industrial catalyst is only 1–2 years depending on the operating conditions. The catalyst consists of a bulk phase of Fe2(MoO4)3 and a surface layer phase of MoO3. The MoO3 surfaceis selective towards formaldehyde while the iron in the sublayer increases...... the activity of the catalyst [2]. Pure MoO3 in itself has low activity. Literature from the last decades agrees that the major reason for the deactivation is loss of molybdenum from the catalyst. Molybdenum forms volatile species with methanol, which can leave behind Mo poor zones. The catalyst is usually...... prepared with excess MoO3 (Mo/Fe > 1.5) to counter the loss of Mo. This work focuses on understanding the structural changes occurring in the catalyst and its behavior during deactivation via prolonged activity testing and spectroscopic investigations....

  14. Assessment of the systemic distribution and toxicity of formaldehyde following pulpotomy treatment: Part one

    Energy Technology Data Exchange (ETDEWEB)

    Ranly, D.M.

    1985-11-01

    This report, the first of a two-part study, was undertaken to quantitate the systemic distribution of formaldehyde from a pulpotomy site, and to compare this level to doses that elicit overt systemic pathology. Maxillary first molars of rats were pulpotomized and treated with 14C-labeled formaldehyde, for 5 minutes. Additionally, four groups of rats were infused with 10, 20, 30, or 50 percent of the first quantity applied to the site. The data show that approximately 30 percent of the 14C-formaldehyde placed in the pulp chamber was distributed systemically; 50 percent to 59 percent was expired as CO2; and 2 percent was excreted.

  15. Early Morning Concentrations of Formaldehyde and Carbon Monoxide in Milano Measured with the Mobile Pollutant Lab

    Energy Technology Data Exchange (ETDEWEB)

    Prevot, A.S.H.; Ordonez, C.; Richer, R.; Junkermann, W. [Forschungszentrum Karlsruhe (Georgia)

    2004-03-01

    Within the EU project FORMAT (Formaldehyde as a tracer of oxidation in the troposphere) measurements were performed in the Po basin around Milano, Italy. Mobile measurements in the centre of Milano in the early morning allowed the determination of the emission ratios of formaldehyde and carbon monoxide. The slope derived from the correlation of measured HCHO and CO was about a factor of 8 lower than the emission ratio of the available emission inventory. This analysis will finally allow a better estimation of primary versus secondary formaldehyde in this region. (author)

  16. PRODUCTION OF HIGH DENSITY PARTICLEBOARD USING MELAMINE-UREA-FORMALDEHYDE RESIN

    Directory of Open Access Journals (Sweden)

    Setsuo Iwakiri

    2005-12-01

    Full Text Available This research was developed aiming to evaluate the effects of board density and melamine-urea-formaldehyde resin onthe properties of particleboard for semi-structural applications. The boards were manufactured with nominal density of 0.65 g/cm³and 0.90 g/cm³ using urea-formaldehyde resin as control and melamine-urea-formaldehyde. The results showed a better dimensionallystability and mechanical properties of the boards manufactured with higher density and MUF resin content. The fine furnish usedfor external layer of particleboard in the industrial process, could be used for high density homogeneous board to semi-strucuturaluses, such as flooring applications.

  17. Successful reduction of morticians' exposure to formaldehyde during embalming procedures.

    Science.gov (United States)

    Hiipakka, D W; Dyrdahl, K S; Garcia Cardenas, M

    2001-01-01

    A case study of the effectiveness of upgraded ventilation engineering controls in a military mortuary facility was performed. Worst-case mortician formaldehyde exposures generated during the use of highly concentrated embalming fluid (required to meet a 2-week preservation standard for overseas case processing and return of the deceased to the continental United States) were documented. A detailed exposure evaluation via consecutive short-term exposure limit (STEL) samples facilitated characterization of the hazard potential for each distinct phase of the embalming process. After baseline screening with 3M passive formaldehyde dosimeters, a total of 145 personal and area STEL sorbent tube samples were collected during six embalming cases between 1994 and 1998. Prior to the installation of local exhaust ventilation controls, personal time-weighted average (TWA) exposure values during embalming activities were 3.19-7.69 ppm for a mean of 4.80 ppm (calculated 8-hour TWA exposures for mortician workshifts were 1.32-2.86 ppm, mean 1.93 ppm). Initial STEL exposures ranged from a low of 0.14 during preembalming body preparation to 20.89 ppm during aspiration of arterial fluids (mean = 4.16 ppm). Embalming room general area samples revealed a mean concentration of 0.76 ppm. With ventilation upgrades installed in 1997, calculated personal 8-hour TWA exposure values during embalming procedures were reduced. STEL exposures decreased to between 0.11 to 3.44 ppm (mean of 0.55 ppm); embalming room general area sample concentrations decreased to a mean of 0.089 ppm. Because occasional 15-min peak exposures continued to exceed the 2.0 ppm Occupational Safety and Health Administration STEL during tasks involving large volumes of embalming fluid or direct contact with paraformaldehyde preservative powders, general room ventilation was further upgraded to 25 room air changes per hour.

  18. SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

    Directory of Open Access Journals (Sweden)

    G. Dufour

    2009-03-01

    Full Text Available Formaldehyde (HCHO is an important intermediate compound in the degradation of volatile organic compounds (VOCs in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1 the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×1015 molecule/cm2 and the model performances evaluated using surface measurements are satisfactory (~13%; (2 the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa to a factor of 2 (Poland, the United Kingdom depending on the regions.

  19. Thermal removal of nitrogen species from wood waste containing urea formaldehyde and melamine formaldehyde resins

    Energy Technology Data Exchange (ETDEWEB)

    Girods, P. [LERMAB, Nancy-Universite, UMR 1093, INRA, ENGREF, UHP, ENSTIB 27, rue du Merle Blanc, BP 1041, 88 051 Epinal (France)], E-mail: pierre.girods@yahoo.fr; Dufour, A.; Rogaume, Y.; Rogaume, C.; Zoulalian, A. [LERMAB, Nancy-Universite, UMR 1093, INRA, ENGREF, UHP, ENSTIB 27, rue du Merle Blanc, BP 1041, 88 051 Epinal (France)

    2008-11-30

    The removal of nitrogen from wood board waste through a low temperature pyrolysis (523-573 K) is investigated with two analytical methods. The kinetic study of the thermal behaviour of wood board and of its components (wood, UF and MF resins) shows the feasibility of removing thermally nitrogen from wood board waste. Indeed, the range of temperatures associated with the degradation of wood is different from the one obtained for the degradation of UF and MF resin. Isothermal conditions enable the determination of a kinetic model for degradation of wood board and of its components and demonstrate that the thermal behaviour of wood board is not the reflection of the sum of its components' behaviour. FTIR analysis of gas products confirms the feasibility removing nitrogen thermally and enables the evaluation of the optimum treatment conditions (temperature/duration). Elementary analysis of the treated samples and study of their low heating value (LHV) enable to quantify the efficiency of the thermal treatment in terms of nitrogen removal and of energy recovery. Results show that around 70% of the initial nitrogen can be removed from the waste, and that the temperature of treatment (between 523 K and 573 K) does not influence the efficiency in terms of nitrogen removal. Nevertheless, the ratio Residual energy/Initial energy (between 76% and 90%) is improved with the lowest temperature of treatment.

  20. Cohort mortality study of garment industry workers exposed to formaldehyde: update and internal comparisons.

    Science.gov (United States)

    Meyers, Alysha R; Pinkerton, Lynne E; Hein, Misty J

    2013-09-01

    To further evaluate the association between formaldehyde and leukemia, we extended follow-up through 2008 for a cohort mortality study of 11,043 US formaldehyde-exposed garment workers. We computed standardized mortality ratios and standardized rate ratios stratified by year of first exposure, exposure duration, and time since first exposure. Associations between exposure duration and rates of leukemia and myeloid leukemia were further examined using Poisson regression models. Compared to the US population, myeloid leukemia mortality was elevated but overall leukemia mortality was not. In internal analyses, overall leukemia mortality increased with increasing exposure duration and this trend was statistically significant. We continue to see limited evidence of an association between formaldehyde and leukemia. However, the extended follow-up did not strengthen previously observed associations. In addition to continued epidemiologic research, we recommend further research to evaluate the biological plausibility of a causal relation between formaldehyde and leukemia. Copyright © 2013 Wiley Periodicals, Inc.

  1. MINIMIZE THE HYDROGENATION OF UNSATURATED FATTY ACID IN RUMEN WITH FORMALDEHYDE

    Directory of Open Access Journals (Sweden)

    Nafly C. Tiven

    2011-07-01

    Full Text Available This research aimed to know the ability of formaldehyde to protect unsaturated fatty acid of CPO on the hydrogenation process by rumen microbes. In this experiment, the in vitro fermentation of rumen fluid was carrying out. It was taken from the rumen-trocar of female sheep. The unsaturated fatty acid source was from CPO (Crude Palm Oil which encapsulated by formaldehyde 37% within 0%, 1%, 2% and 3%. The data was analyzed by Completely Random Design with Duncan's New Multiple Range Test. The difference of means the treatments were tested by Duncan's New Multiple Range Test. Result showed that oleic and linoleic resulting from fermenting CPO protected by formaldehyde was increase if it was compared with the unprotected CPO. It can be concluded that encapsulated CPO with formaldehyde was able to prevent hydrogenating of unsaturated fatty acid, mainly oleic and linoleic.

  2. Localization of formaldehyde production during frozen storage of European hake ( Merluccius merluccius )

    DEFF Research Database (Denmark)

    Rey-Mansilla, M.D.; Sotelo, C.G.; Aubourg, S.P.

    2001-01-01

    The formation of dimethylamine and formaldehyde from trimethylamine N-oxide by the enzyme trimethylamine N-oxide demethylase in whole hake during frozen storage was studied. The objective was to check if there were parts of the muscle with a higher production of dimethylamine and formaldehyde...... the viscera, and the tail. The second variable was the temperature of storage, -11 degreesC or -18 degreesC. Finally, the influence of kidneys during storage, comparing fish with and without kidneys, was also evaluated. No differences were found in dimethylamine and formaldehyde production between fish...... with and without kidneys stored at -18 degreesC. However at -11 degreesC the amounts of dimethylamine and formaldehyde detected in fish without kidneys were, in some cases, higher than in those with kidneys. Kidney removal does not have a statistically significant influence on DMA and FA production in frozen...

  3. FIAM-pwp-Formaldehyde Indoor Air Model – Pressed Wood Products

    Science.gov (United States)

    The Formaldehyde Indoor Air Model-pressed wood products (FIAM-pwp) user guide contains information on the equations and defaults used to estimate exposure from formaldehye emitted from pressed wood products.

  4. Prepublication Copy: Voluntary Consensus Standards Update; Formaldehyde Emission Standards for Composite Wood Products

    Science.gov (United States)

    Prepublication copy of the final rule Voluntary Consensus Standards Update; Formaldehyde Emission Standards for Composite Wood Products. Updates several voluntary consensus standards listed at 40 CFR § 770.99.

  5. Occupational exposure to formaldehyde, hematotoxicity, and leukemia-specific chromosome changes in cultured myeloid progenitor cells.

    NARCIS (Netherlands)

    Zhang, L.; Tang, X.; Rothman, N.; Vermeulen, R.; Ji, Z.; Shen, M.; Qiu, C.; Guo, W.; Liu, S.; Reiss, B.; Freeman, L.B.; Ge, Y.; Hubbard, A.E.; Hua, M.; Blair, A.; Galvan, N.; Ruan, X.; Alter, B.P.; Xin, K.X.; Li, S.; Moore, L.E.; Kim, S.; Xie, Y.; Hayes, R.B.; Azuma, M.; Hauptmann, M.; Xiong, J.; Stewart, P.; Li, L.; Rappaport, S.M.; Huang, H.; Fraumeni, J.F.; Smith, M.T.; Lan, Q.

    2010-01-01

    There are concerns about the health effects of formaldehyde exposure, including carcinogenicity, in light of elevated indoor air levels in new homes and occupational exposures experienced by workers in health care, embalming, manufacturing, and other industries. Epidemiologic studies suggest that

  6. Formaldehyde Exposure and Mortality Risks From Acute Myeloid Leukemia and Other Lymphohematopoietic Malignancies in the US National Cancer Institute Cohort Study of Workers in Formaldehyde Industries

    Science.gov (United States)

    Dell, Linda D.; Boffetta, Paolo; Gallagher, Alexa E.; Crawford, Lori; Lees, Peter SJ.; Mundt, Kenneth A.

    2015-01-01

    Objectives: To evaluate associations between cumulative and peak formaldehyde exposure and mortality from acute myeloid leukemia (AML) and other lymphohematopoietic malignancies. Methods: Cox proportional hazards analyses. Results: Acute myeloid leukemia was unrelated to cumulative exposure. Hodgkin lymphoma relative risk estimates in the highest exposure categories of cumulative and peak exposures were, respectively, 3.76 (Ptrend = 0.05) and 5.13 (Ptrend = 0.003). There were suggestive associations with peak exposure observed for chronic myeloid leukemia, albeit based on very small numbers. No other lymphohematopoietic malignancy was associated with either chronic or peak exposure. Conclusions: Insofar as there is no prior epidemiologic evidence supporting associations between formaldehyde and either Hodgkin leukemia or chronic myeloid leukemia, any causal interpretations of the observed risk patterns are at most tentative. Findings from this re-analysis do not support the hypothesis that formaldehyde is a cause of AML. PMID:26147546

  7. Formaldehyde alters triglyceride synthesis and very low-density lipoprotein secretion in a time-dependent manner.

    Science.gov (United States)

    Bai, Jianying; Wang, Pan; Liu, Yanfei; Zhang, Yan; Li, Yaofu; He, Zhen; Hou, Lifang; Liang, Ruifeng

    2017-12-01

    Formaldehyde is a common indoor air pollutant that is toxic to the liver. This study aimed to investigate the effects of formaldehyde on triglyceride metabolism in human hepatocellular carcinoma cells (HepG2). Cell viability was detected using a MTT (3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide) assay. Following treatment with different concentrations of formaldehyde for 24 and 48h, the intra and extra-hepatocellular triglyceride (TG) content was determined using a chemical-enzymatic method; Western blotting was used to detect the levels of fatty acid synthesis and VLDL-related proteins. Our results showed that cell viability significantly decreased after formaldehyde treatment (0.5-12.5mM, 24/48h). Extracellular TG levels in the hepatocytes increased after formaldehyde treatment at 0.004mM-0.1mM for 24h. SREBP-1c, ACC, FASN, and MTP, CES3 and DGAT1 proteins increased significantly after 24h of formaldehyde treatment. Intracellular TG levels decreased for 48h treatment of formaldehyde. AMPKα increased significantly in all tested groups and p-AMPK increased significantly after 0.1mM formaldehyde treatment for 48h. Our results indicated that short-term formaldehyde exposure balances triglyceride metabolism by promoting hepatocellular TG synthesis and VLDL secretion; Long-term formaldehyde disturbs the TG metabolism balance in the hepatocytes. Copyright © 2017. Published by Elsevier B.V.

  8. MEMS based pyroelectric thermal energy harvester

    Science.gov (United States)

    Hunter, Scott R; Datskos, Panagiotis G

    2013-08-27

    A pyroelectric thermal energy harvesting apparatus for generating an electric current includes a cantilevered layered pyroelectric capacitor extending between a first surface and a second surface, where the first surface includes a temperature difference from the second surface. The layered pyroelectric capacitor includes a conductive, bimetal top electrode layer, an intermediate pyroelectric dielectric layer and a conductive bottom electrode layer. In addition, a pair of proof masses is affixed at a distal end of the layered pyroelectric capacitor to face the first surface and the second surface, wherein the proof masses oscillate between the first surface and the second surface such that a pyroelectric current is generated in the pyroelectric capacitor due to temperature cycling when the proof masses alternately contact the first surface and the second surface.

  9. MEMS based Doppler velocity measurement system

    Science.gov (United States)

    Shin, Minchul

    The design, fabrication, modeling and characterization of a capacitive micromachined ultrasonic transducer (cMUT) based in-air Doppler velocity measurement system using a 1 cm2 planar array are described. Continuous wave operation in a narrowband was chosen in order to maximize range, as it allows for better rejection of broadband noise. The sensor array has a 160-185 kHz resonant frequency to achieve a 10 degree beamwidth. A model for the cMUT and the acoustic system which includes electrical, mechanical, and acoustic components is provided. Furthermore, characterization of the cMUT sensor with a variety of testing procedures is provided. Laser Doppler vibrometry (LDV), beampattern, reflection, and velocity testing characterize the performance of the sensors. The sensor is capable of measuring the velocity of a moving specular reflector with a resolution of 5 cm/s, an update rate of 0.016 second, and a range of 1.5 m.

  10. Mems based valveless micropump for biomedical applications

    CSIR Research Space (South Africa)

    Van der Merwe, SW

    2010-01-01

    Full Text Available is a minimum. Bistable steady-stall flow occurs when the flow flip-flops between the diffuser walls and performance is poor in this region. Flow is said to be in the jet flow region when it separates completely from the diffuser walls and passes...

  11. A Novel Structure for MEMS Based Varactors

    Directory of Open Access Journals (Sweden)

    Ebrahim Abbaspour-Sani

    2006-08-01

    Full Text Available A novel structure with electro-mechanically tunable capacitor for RF application is presented. The suspended electrodes are designed in such a way that both are electrostaticaly displaceable. This double plate moveability feature of the capacitor increases the tuning range. In this structure, there is no need for cantilever beams, which introduce considerable series resistance to the capacitor and decrease the quality factor. Therefore, our proposed varactor achieves better Q in a smaller area. The simulated one pF capacitor shows a Q of 40 at 1 GHz and a tuning range of 42%. Pull-in voltage is 3.6 V, which is a reasonable value for submicron CMOS technologies.

  12. MEMS based impedimetric sensing of phthalates

    KAUST Repository

    Zia, Asif I.

    2013-05-01

    Phthalate esters are known ubiquitous teratogenic and carcinogenic environmental and food pollutants. Their detection and quantification is strictly laboratory based, time consuming, expensive and professionally handled procedure. Presented research work describes a real time non-invasive detection technique for phthalates detection in ethanol, water and drinks. The new type of inter-digital sensor design incorporating multiple sensing gold electrodes were fabricated on silicon substrate based on thin film micro-electromechanical system (MEMS) using semiconductor device fabrication technology. A passivation layer of Silicon Nitride (Si3N4) was used to functionalize the sensor. Various concentrations (0.1 to 20ppm) of DINP (di-isononyl phthalates) in ethanol and di (2-ethylhexyl) phthalate (DEHP) in deionized MilliQ water were subjected to the testing system by dip testing method. Electrochemical impedance spectroscopy (EIS) technique was used to obtain impedance spectra in order to determine sample conductance for evaluation of its dielectric properties. The impedance spectra so obtained showed that the sensor was able to detect the presence of phthalates in the samples distinctively. Electrochemical Spectrum Analyser was used to model the experimentally obtained impedance spectra by curve fitting technique to figure out Constant Phase Element (CPE) equivalent circuit. Locally available energy drink and juice was added with phthalates in concentrations of 2, 6 and 10ppm to observe the performance of the sensor in such products. Experimental results showed that the new sensor was able to detect different concentrations of phthalates in energy drinks. © 2013 IEEE.

  13. Formaldehyd i tekstil som mulig årsag til arthritis og angioødem

    DEFF Research Database (Denmark)

    Jensen, O C; Bach, B

    1992-01-01

    A case of arthritis and angioedema which developed on occupational exposure to formaldehyde in textiles is described. Possible pathological mechanisms are discussed. The suspicion that an unknown immunological reaction may be the cause is raised.......A case of arthritis and angioedema which developed on occupational exposure to formaldehyde in textiles is described. Possible pathological mechanisms are discussed. The suspicion that an unknown immunological reaction may be the cause is raised....

  14. Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver.

    Science.gov (United States)

    Uchikawa, Takuya; Kanno, Toshihiro; Maruyama, Isao; Mori, Nobuko; Yasutake, Akira; Ishii, Yuji; Yamada, Hideyuki

    2016-01-01

    Methylmercury (MeHg) is gradually changed to inorganic Hg after demethylation in animal tissues, and a selective quantification of inorganic Hg in the tissues is necessary to detect the reaction. We detected inorganic Hg formation in liver and kidney of mouse as early as 24 hr after MeHg injection. As an example of biological demethylation, the cytochrome P450 (P450)-mediated N-demethylation of drugs has been well documented, and formaldehyde was detected as a reaction product. Here we incubated mouse liver homogenate with added MeHg and observed a dose-dependent production of formaldehyde, as well as inorganic Hg formation. Since the amount of formaldehyde was approx. 500 times higher than that of the inorganic Hg that formed, the formaldehyde production would be stimulated by inorganic Hg formed from MeHg. We observed that inorganic Hg caused formaldehyde production, and it was enhanced by L-methionine and sarcosine. Thus, some biomolecules with S-methyl and N-methyl groups may function as methyl donors in the reaction. Using subcellular fractions of mouse liver, we observed that microsomal P450 did not participate in the demethylation of MeHg, but the greatest activity was located in the mitochondria-rich fraction. The addition of superoxide anion in the reaction mixture significantly enhanced the formaldehyde production, whereas Mn-superoxide dismutase depressed the reaction. Our present findings demonstrated that inorganic Hg formed by MeHg demethylation in mouse liver stimulated the endogenous formaldehyde production, and we observed that MeHg demethylation could be estimated by a formaldehyde analysis. Our results also suggested that superoxide anion is involved in the reaction.

  15. [Critical approach to technics for the disinfection of respirators with formaldehyde].

    Science.gov (United States)

    Laguenie, G; Bavoux, F; Garnier, R; Murat, I; Couturier, C

    1983-03-01

    Method of artificial respirators desinfection by Formaldehyde is studied. Formaldehyde and ammoniac quantitative analysis are performed. Air samples are taken by dry process and by wet process. Two concentrations are in ceiling values for exposure of workers and exceed irritant concentrations during chronic exposition. Particular attention should be paid to perform measurement: air samples must be taken by wet process as artificial ventilation circumstances: indeed in this case air is humidified; potential toxicity is unappreciated in this use. Complementary studies are required.

  16. Adsorption of Pb, Cd, Zn, Cu and Hg ions on Formaldehyde and ...

    African Journals Online (AJOL)

    Adsorption of Pb(II), Cd(II), Zn(II), Cu(II) and Hg(II) ions on formaldehyde and Pyridine modified bean husks were determined. The adsorption capacity of formaldehyde modified bean husks (mg/g) was: Pb2+, 5.01; Cd2+, 3.63; Zn2+, 2.18; Hg2+, 1.82; Cu2+, 1.58 and that of pyridine modified bean husk was: Hg2+, 6.92; Cd2+ ...

  17. Performance of optical biosensor using alcohol oxidase enzyme for formaldehyde detection

    Science.gov (United States)

    Sari, A. P.; Rachim, A.; Nurlely, Fauzia, V.

    2017-07-01

    The recent issue in the world is the long exposure of formaldehyde which is can increase the risk of human health, therefore, that is very important to develop a device and method that can be optimized to detect the formaldehyde elements accurately, have a long lifetime and can be fabricated and produced in large quantities. A new and simple prepared optical biosensor for detection of formaldehyde in aqueous solutions using alcohol oxidase (AOX) enzyme was successfully fabricated. The poly-n-butyl acrylic-co-N-acryloxysuccinimide (nBA-NAS) membranes containing chromoionophore ETH5294 were used for immobilization of alcohol oxidase enzyme (AOX). Biosensor response was based on the colour change of chromoionophore as a result of enzymatic oxidation of formaldehyde and correlated with the detection concentration of formaldehyde. The performance of biosensor parameters were measured through the optical absorption value using UV-Vis spectrophotometer including the repeatability, reproducibility, selectivity and lifetime. The results showed that the prepared biosensor has good repeatability (RSD = 1.9 %) and good reproducibility (RSD = 2.1 %). The biosensor was selective formaldehyde with no disturbance by methanol, ethanol, and acetaldehyde, and also stable before 49 days and decrease by 41.77 % after 49 days.

  18. Human health risks of formaldehyde indoor levels: An issue of concern.

    Science.gov (United States)

    Rovira, Joaquim; Roig, Neus; Nadal, Martí; Schuhmacher, Marta; Domingo, José L

    2016-01-01

    Formaldehyde is a carcinogenic substance for humans. Exposure to formaldehyde may also cause eye and respiratory tract irritation, as well as skin sensitization. The main indoor sources of formaldehyde are wood-pressed products, insulation materials, paints, varnishes, household cleaning products and cigarettes, among others. Although this chemical is a well-known indoor pollutant, data on indoor concentrations of formaldehyde are still scarce in some countries. In February 2014, 10 homes in Catalonia, Spain, were randomly selected to collect indoor (bedroom and living room) and outdoor air samples. Ten additional samples were also collected at different workplaces (e.g., offices, shops, classrooms, etc.). Formaldehyde air levels found in homes ranged from 10.7 to 47.7 μg m(-3), from 9.65 to 37.2 μg m(-3), and from 0.96 to 3.37 μg m(-3) in bedrooms, living rooms, and outdoors, respectively. Meanwhile, at workplaces, indoor air levels ranged from 5.86 to 40.4 μg m(-3). These levels are in agreement with data found in the scientific literature. Non-carcinogenic risks were above the threshold limit (HQ > 1), and carcinogenic risks were not acceptable either (>10(-4)). Despite the current study limitations, the results confirm that formaldehyde indoor levels are a matter of health concern, which must be taken into account by policymakers and regulatory bodies.

  19. Analysis of formaldehyde in the atmosphere collected by EPA TO11 method with GC-FID

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Hongmao; Fryters, T.; Brassard, B. [CHEMEX, Edmonton, Alberta (Canada)

    1996-12-31

    Formaldehyde is an important pollutant in the atmosphere. It has been known as a major promoter in the formation of ozone because it can provide an immediate source of free radicals (HO{sub 2}) needed for the formation of ozone. The monitoring of formaldehyde in the atmosphere includes using spectroscopic techniques such as Fourier transform infrared spectrometry (FTIR) and optical adsorption spectrometry (ODAS) and solution/sorbent adsorption techniques (such as EPA TO11 and TO5 methods). EPA TO11 and TO5 methods are based on using 2,4-dinitrophenylhydrozine as a derivatization reagent for collection of formaldehyde in the atmosphere and then the extracts of the derivatized formaldehyde are analyzed by the HFLC. In this paper, a GC-FID technique is reported for analyzing the extract of formaldehyde derivation collected by the EPA TO11 method. The GC method has been extensively evaluated and compared with the HFLC method. Some field formaldehyde results are also reported in this paper.

  20. NMR studies of the equilibria and reaction rates in aqueous solutions of formaldehyde.

    Science.gov (United States)

    Rivlin, Michal; Eliav, Uzi; Navon, Gil

    2015-03-26

    Formaldehyde has an important role in the chemical industry and in biological sciences. In dilute aqueous solutions of formaldehyde only traces of the molecular formaldehyde are present and the predominant species are methylene glycol and in lower concentrations, dimethylene glycol. The chemical equilibria and reaction rates of the hydration of formaldehyde in H2O and D2O solutions at low concentrations were studied by (1)H and (13)C NMR at various conditions of pH (1.8-7.8) and temperature (278-333 K). These measurements became possible by direct detection of formaldehyde (13)C and (1)H peaks. The equilibrium and rate constants of the dimerization reaction of methylene glycol were also measured. The rate constants for both the hydration and the dimerization reactions were measured by a new version of the conventional selective inversion transfer method. This study, together with previous published work, completes the description of dynamics and equilibria of all the processes occurring in dilute aqueous formaldehyde solutions.

  1. Occupational Exposure and Health Impairments of Formaldehyde on Employees of a Wood Industry.

    Science.gov (United States)

    Jafari, Mohammad Javad; Rahimi, Abolfazl; Omidi, Leila; Behzadi, Mohammad Hassan; Rajabi, Mohammad Hassan

    2015-01-01

    Occupational exposure to formaldehyde may decrease white blood cell counts and change blood concentration. In this study, the influences of occupational exposure to formaldehyde on the number of white blood cells and blood concentrations were studied. This case-control study was conducted in June of 2012 at North Wood Factory, Golestan Province, Iran. The US-NIOSH method No. 2541 was used to determine the occupational exposure of 30 workers of the production line (case group) and 30 administrative staffs (control group) to formalde-hyde. The number of white blood cells and blood concentration were determined using the normal blood count method and related indices. Demographic features as well as the symptoms of being exposed to formaldehyde were collected using a standard questionnaire. The occupational exposure of case group ranged from 0.50 ppm to 1.52 ppm. The prevalence of all studied symptoms from formaldehyde exposure in workers (2formaldehyde changed the blood concentration of the studied workers but did not change the number of their white blood cells.

  2. ATLASGAL-selected massive clumps in the inner Galaxy. VI. Kinetic temperature and spatial density measured with formaldehyde

    Science.gov (United States)

    Tang, X. D.; Henkel, C.; Wyrowski, F.; Giannetti, A.; Menten, K. M.; Csengeri, T.; Leurini, S.; Urquhart, J. S.; König, C.; Güsten, R.; Lin, Y. X.; Zheng, X. W.; Esimbek, J.; Zhou, J. J.

    2018-03-01

    Context. Formaldehyde (H2CO) is a reliable tracer to accurately measure the physical parameters of dense gas in star-forming regions. Aim. We aim to determine directly the kinetic temperature and spatial density with formaldehyde for the 100 brightest ATLASGAL-selected clumps (the TOP100 sample) at 870 μm representing various evolutionary stages of high-mass star formation. Methods: Ten transitions (J = 3-2 and 4-3) of ortho- and para-H2CO near 211, 218, 225, and 291 GHz were observed with the Atacama Pathfinder EXperiment (APEX) 12 m telescope. Results: Using non-LTE models with RADEX, we derived the gas kinetic temperature and spatial density with the measured para-H2CO 321-220/303-202, 422-321/404-303, and 404-303/303-202 ratios. The gas kinetic temperatures derived from the para-H2CO 321-220/303-202 and 422-321/404-303 line ratios are high, ranging from 43 to >300 K with an unweighted average of 91 ± 4 K. Deduced Tkin values from the J = 3-2 and 4-3 transitions are similar. Spatial densities of the gas derived from the para-H2CO 404-303/303-202 line ratios yield 0.6-8.3 × 106 cm-3 with an unweighted average of 1.5 (±0.1) × 106 cm-3. A comparison of kinetic temperatures derived from para-H2CO, NH3, and dust emission indicates that para-H2CO traces a distinctly higher temperature than the NH3 (2, 2)/(1, 1) transitions and the dust, tracing heated gas more directly associated with the star formation process. The H2CO line widths are found to be correlated with bolometric luminosity and increase with the evolutionary stage of the clumps, which suggests that higher luminosities tend to be associated with a more turbulent molecular medium. It seems that the spatial densities measured with H2CO do not vary significantly with the evolutionary stage of the clumps. However, averaged gas kinetic temperatures derived from H2CO increase with time through the evolution of the clumps. The high temperature of the gas traced by H2CO may be mainly caused by radiation from

  3. Effect of Formaldehyde on Human Middle Ear Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Shin Hye Kim

    2018-01-01

    Full Text Available Formaldehyde (FA is a familiar indoor air pollutant found in everything from cosmetics to clothing, but its impact on the middle ear is unknown. This study investigated whether FA causes cytotoxicity, inflammation, or induction of apoptosis in human middle ear epithelial cells (HMEECs. Cell viability was investigated using the trypan blue assay and a cell counting kit (CCK-8 in HMEECs treated with FA for 4 or 24 h. The expression of genes encoding the inflammatory cytokine tumor necrosis factor alpha (TNF-α and mucin (MUC5AC was analyzed using RT-PCR. Activation of the apoptosis pathway was determined by measuring mitochondrial membrane potential (MMP, cytochrome oxidase, caspase-9/Mch6/Apaf 3, and Caspase-Glo® 3/7 activities. The CCK-8 assay and trypan blue assay results showed a reduction in cell viability in FA-treated HMEECs. FA also increased the cellular expression of TNF-α and MUC5AC and reduced the activities of MMP and cytochrome oxidase. Caspase-9 activity increased in cells stimulated for 4 h, as well as caspase-3/7 activity in cells stimulated for 24 h. The decreased cell viability, the induction of inflammation and mucin gene expression, and the activation of the apoptosis pathway together indicate a link between environmental FA exposure and the development of otitis media.

  4. Systematic studies of tannin–formaldehyde aerogels: preparation and properties

    International Nuclear Information System (INIS)

    Amaral-Labat, Gisele; Szczurek, Andrzej; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2013-01-01

    Gelation of tannin–formaldehyde (TF) solutions was systematically investigated by changing pH and concentration of TF resin in water. In this way we constructed the TF phase diagram, from which chemical hydrogels could be described, and also synthesized thermoreversible tannin-based hydrogels. Conditions of non-gelation were also determined. Hydrogels were dried in supercritical CO 2 , leading to a broad range of TF aerogels. The latter were investigated for volume shrinkage, total porosity, micro-, meso- and macropore volumes, Brunauer–Emmett–Teller (BET) surface area, microscopic texture, mechanical and thermal properties. All these properties are discussed in relation to each other, leading to an accurate and self-consistent description of these bioresource-based highly porous materials. The conditions for obtaining the highest BET surface area or mesopore volume were determined and explained in relation to the preparation conditions. The highest BET surface area, 880 m 2 g −1 , is remarkably high for organic aerogels derived from a natural resource. (paper)

  5. Systematic studies of tannin-formaldehyde aerogels: preparation and properties

    Science.gov (United States)

    Amaral-Labat, Gisele; Szczurek, Andrzej; Fierro, Vanessa; Pizzi, Antonio; Celzard, Alain

    2013-02-01

    Gelation of tannin-formaldehyde (TF) solutions was systematically investigated by changing pH and concentration of TF resin in water. In this way we constructed the TF phase diagram, from which chemical hydrogels could be described, and also synthesized thermoreversible tannin-based hydrogels. Conditions of non-gelation were also determined. Hydrogels were dried in supercritical CO2, leading to a broad range of TF aerogels. The latter were investigated for volume shrinkage, total porosity, micro-, meso- and macropore volumes, Brunauer-Emmett-Teller (BET) surface area, microscopic texture, mechanical and thermal properties. All these properties are discussed in relation to each other, leading to an accurate and self-consistent description of these bioresource-based highly porous materials. The conditions for obtaining the highest BET surface area or mesopore volume were determined and explained in relation to the preparation conditions. The highest BET surface area, 880 m2 g-1, is remarkably high for organic aerogels derived from a natural resource.

  6. A new formaldehyde sensor from silver nanoclusters modified Tollens' reagent.

    Science.gov (United States)

    Chaiendoo, Kanokwan; Sooksin, Sawarin; Kulchat, Sirinan; Promarak, Vinich; Tuntulani, Thawatchai; Ngeontae, Wittaya

    2018-07-30

    A selective colorimetric assay for detecting formaldehyde (FA) was proposed based on silver nanoclusters (AgNCs) templated by polymethacrylic acid (PMAA). The chemodosimeter was easily fabricated by the formation of Tollens' reagent in the presence of AgNCs (AgNCs@Tollens). The detection principle was based on the change in the color caused by the change in the particle size from nanoclusters (no LSPR) to nanoparticles (with LSPR) upon the reduction of Tollens' reagent by FA. In the presence of FA, the intensity of a new absorbance band with a maximum at a wavelength of 430 nm corresponding to the LSPR of the AgNPs linearly increased as a function of the FA concentration, exhibiting a color change that could be observed by the naked eye. This method provided a working range of 30-50 µM with lower detection limit (LOD) of 27.99 µM. The proposed method exhibited excellent selectivity towards FA over other aldehyde-containing compounds. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations; Exposition par inhalation au formaldehyde dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  8. Potential Exposure and Cancer Risk from Formaldehyde Emissions from Installed Chinese Manufactured Laminate Flooring.

    Science.gov (United States)

    Sheehan, Patrick; Singhal, Ankur; Bogen, Kenneth T; MacIntosh, David; Kalmes, Renee M; McCarthy, John

    2017-11-15

    Lumber Liquidators (LL) Chinese-manufactured laminate flooring (CLF) has been installed in >400,000 U.S. homes over the last decade. To characterize potential associated formaldehyde exposures and cancer risks, chamber emissions data were collected from 399 new LL CLF, and from LL CLF installed in 899 homes in which measured aggregate indoor formaldehyde concentrations exceeded 100 μg/m 3 from a total of 17,867 homes screened. Data from both sources were combined to characterize LL CLF flooring-associated formaldehyde emissions from new boards and installed boards. New flooring had an average (±SD) emission rate of 61.3 ± 52.1 μg/m 2 -hour; >one-year installed boards had ∼threefold lower emission rates. Estimated emission rates for the 899 homes and corresponding data from questionnaires were used as inputs to a single-compartment, steady-state mass-balance model to estimate corresponding residence-specific TWA formaldehyde concentrations and potential resident exposures. Only ∼0.7% of those homes had estimated acute formaldehyde concentrations >100 μg/m 3 immediately after LL CLF installation. The TWA daily formaldehyde inhalation exposure within the 899 homes was estimated to be 17 μg/day using California Proposition 65 default methods to extrapolate cancer risk (below the regulation "no significant risk level" of 40 μg/day). Using a U.S. Environmental Protection Agency linear cancer risk model, 50th and 95th percentile values of expected lifetime cancer risk for residents of these homes were estimated to be 0.33 and 1.2 per 100,000 exposed, respectively. Based on more recent data and verified nonlinear cancer risk assessment models, LL CLF formaldehyde emissions pose virtually no cancer risk to affected consumers. © 2017 Society for Risk Analysis.

  9. Low-Dose Formaldehyde Delays DNA Damage Recognition and DNA Excision Repair in Human Cells

    Science.gov (United States)

    Luch, Andreas; Frey, Flurina C. Clement; Meier, Regula; Fei, Jia; Naegeli, Hanspeter

    2014-01-01

    Objective Formaldehyde is still widely employed as a universal crosslinking agent, preservative and disinfectant, despite its proven carcinogenicity in occupationally exposed workers. Therefore, it is of paramount importance to understand the possible impact of low-dose formaldehyde exposures in the general population. Due to the concomitant occurrence of multiple indoor and outdoor toxicants, we tested how formaldehyde, at micromolar concentrations, interferes with general DNA damage recognition and excision processes that remove some of the most frequently inflicted DNA lesions. Methodology/Principal Findings The overall mobility of the DNA damage sensors UV-DDB (ultraviolet-damaged DNA-binding) and XPC (xeroderma pigmentosum group C) was analyzed by assessing real-time protein dynamics in the nucleus of cultured human cells exposed to non-cytotoxic (formaldehyde concentrations. The DNA lesion-specific recruitment of these damage sensors was tested by monitoring their accumulation at local irradiation spots. DNA repair activity was determined in host-cell reactivation assays and, more directly, by measuring the excision of DNA lesions from chromosomes. Taken together, these assays demonstrated that formaldehyde obstructs the rapid nuclear trafficking of DNA damage sensors and, consequently, slows down their relocation to DNA damage sites thus delaying the excision repair of target lesions. A concentration-dependent effect relationship established a threshold concentration of as low as 25 micromolar for the inhibition of DNA excision repair. Conclusions/Significance A main implication of the retarded repair activity is that low-dose formaldehyde may exert an adjuvant role in carcinogenesis by impeding the excision of multiple mutagenic base lesions. In view of this generally disruptive effect on DNA repair, we propose that formaldehyde exposures in the general population should be further decreased to help reducing cancer risks. PMID:24722772

  10. Study of Necrosis in the Liver of Formaldehyde and Benzo(αPyrene Exposured-Mice

    Directory of Open Access Journals (Sweden)

    Ahmad Soni

    2013-04-01

    Full Text Available Formaldehyde and benzo(αpyrene are compounds that harmful for health. Misapplication of this compound has an impact in the form of organ damage in the body. This study aims to determine the impact of the treatment of the combined exposure of formaldehyde and benzo(αpyrene to cell necrosis in the liver of mice (Mus musculus. Treatment of formaldehyde dose of 25 mg/kg BW to mice was given orally every day for 60 days. Treatment of benzo(αpyrene via intraperitoneal injection at a dose of 250 mg/kg BW were given after 30 days of incubation with four times injection with one day interval. Liver organ histological preparations were made through the HE staining. Observations were made by using a microscope for liver organ preparations. The data obtained that is the percentage of cells necrosis and necrotic foci. This research used Completely Randomized Design (CRD with 95% confidence interval. Liver organ preparations observations indicate that the percentage of necrosis in the untreated control, benzo(αpyrene 250 mg/kg BW, formaldehyde 25 mg/kg BW, combination of formaldehyde 25 mg/kg BW with BaP in a row that is equal to 14.43% ± 0.91; 26.05% ± 3.75; 49.38% ± 2.66; 51.86 ± 1.73. The mean of necrotic foci in liver organ formed in the untreatment control, benzo(αpyrene 250 mg/kg BW, Formaldehyde 25 mg/kg BW, and the combination of formaldehyde 25 mg/kg BW with BaP in a row, equal to 1.3 ± 0,07; 1.63 ± 0.61; 2 ± 0.51, and 3.4 ± 0.76. This suggests that the combined treatment had the highest level of toxicity compared with other treatments.

  11. The Australian Work Exposures Study: Prevalence of Occupational Exposure to Formaldehyde.

    Science.gov (United States)

    Driscoll, Timothy R; Carey, Renee N; Peters, Susan; Glass, Deborah C; Benke, Geza; Reid, Alison; Fritschi, Lin

    2016-01-01

    The aims of this study were to produce a population-based estimate of the prevalence of work-related exposure to formaldehyde, to identify the main circumstances of exposure and to describe the use of workplace control measures designed to decrease those exposures. The analysis used data from the Australian Workplace Exposures Study, a nationwide telephone survey, which investigated the current prevalence and exposure circumstances of work-related exposure to 38 known or suspected carcinogens, including formaldehyde, among Australian workers aged 18-65 years. Using the web-based tool OccIDEAS, semi-quantitative information was collected about exposures in the current job held by the respondent. Questions were addressed primarily at tasks undertaken rather than about self-reported exposures. Of the 4993 included respondents, 124 (2.5%) were identified as probably being exposed to formaldehyde in the course of their work [extrapolated to 2.6% of the Australian working population-265 000 (95% confidence interval 221 000-316 000) workers]. Most (87.1%) were male. About half worked in technical and trades occupations. In terms of industry, about half worked in the construction industry. The main circumstances of exposure were working with particle board or plywood typically through carpentry work, building maintenance, or sanding prior to painting; with the more common of other exposures circumstances being firefighters involved in fighting fires, fire overhaul, and clean-up or back-burning; and health workers using formaldehyde when sterilizing equipment or in a pathology laboratory setting. The use of control measures was inconsistent. Workers are exposed to formaldehyde in many different occupational circumstances. Information on the exposure circumstances can be used to support decisions on appropriate priorities for intervention and control of occupational exposure to formaldehyde, and estimates of burden of cancer arising from occupational exposure to formaldehyde

  12. Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Song, E-mail: niusong84@163.com; Yan, Hongxia, E-mail: hongxiayan@nwpu.edu.cn

    2015-04-28

    Highlights: • A novel silicone-based polymer with active methylene was explored. • Surface tension of liquid paints could be lowered using the polymer. • The polymer was easy to migrate toward the air-coating interface. • Free HCHO could effectively be removed using the polymer. • A lights on HCHO reduction without complicated preparation procedure was shielded. - Abstract: Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by {sup 13}C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4 wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals.

  13. XPS study of organic/MoO3 hybrid thin films for aldehyde gas sensors. Correlation between average Mo valance and sensitivity

    International Nuclear Information System (INIS)

    Itoh, Toshio; Matsubara, Ichiro; Shin, Woosuck; Izu, Noriya; Nishibori, Maiko

    2010-01-01

    We investigate the formaldehyde gas sensing properties of poly(5,6,7,8-tetrahydro-1-naphthylamine)-intercalated MoO 3 thin films ((PTHNA) x MoO 3 ). The resistance responses of (PTHNA) x MoO 3 to formaldehyde increase with increasing intercalation temperature. X-ray photoelectron spectroscopy reveals that the molar ratio of Mo 5+ decreases with increasing intercalation temperature. (author)

  14. Observing atmospheric formaldehyde (HCHO) from space: validation, intercomparison, trend analysis and public health implications

    Science.gov (United States)

    Zhu, L.; Jacob, D.; Kim, P. S.; Fisher, J. A.; Yu, K.; Travis, K.; Mickley, L. J.; Yantosca, R.; Payer Sulprizio, M.; De Smedt, I.; Gonzalez Abad, G.; Chance, K.; Li, C.; Ferrare, R. A.; Fried, A.; Hair, J. W.; Hanisco, T. F.; Richter, D.; Scarino, A. J.; Walega, J.; Weibring, P.; Wolfe, G. M.

    2016-12-01

    Formaldehyde (HCHO) column data from satellites are widely used as a proxy for emissions of volatile organic compounds (VOCs), but validation of the data has been extremely limited. Here we use highly accurate HCHO aircraft observations from the NASA SEAC4RS campaign over the Southeast US in August-September 2013 to validate and intercompare six retrievals of HCHO columns from four different satellite instruments (OMI, GOME2A, GOME2B and OMPS) and three different research groups. The GEOS-Chem chemical transport model is used as a common intercomparison platform to indirectly validate the satellite retrievals with in situ observations. All retrievals feature a HCHO maximum over Arkansas and Louisiana, consistent with the aircraft observations and GEOS-Chem, and reflecting high emissions of biogenic isoprene. The retrievals are also broadly consistent in their spatial variability over the Southeast US (r=0.4-0.8 on a 0.5o×0.5o grid) as well as their day-to-day variability (r=0.5-0.8). Validation results show that HCHO column data provide a reliable proxy for isoprene emission variability but with a low mean bias (20-51%) due both to the spectral fitting and the scattering weights used in the retrievals. We then apply the corrected OMI data to conduct the two following studies. (1) We examine trend in HCHO columns from 2005 to 2014 over the North America. OMI clearly captures trends associated with anthropogenic emission control near Houston, oil/gas production increase over Oil Sands as well as land cover changes over the Southeast US. (2) We drive a fine surface ambient HCHO concentration map (0.2o×0.2o) based on oversampled HCHO columns, localized HCHO vertical profiles sampled from GEOS-Chem, and diurnal variations in surface HCHO measured at various sites. We estimate a total number of 7000 lifelong cancer risks due to exposure of ambient HCHO.

  15. Gas and Gas Pains

    Science.gov (United States)

    ... to produce gas. Often, relatively simple changes in eating habits can lessen bothersome gas. Certain digestive system disorders, ... such as soda and beer, increase stomach gas. Eating habits, such as eating too quickly, drinking through a ...

  16. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage.

    Science.gov (United States)

    Yu, Rui; Lai, Yongquan; Hartwell, Hadley J; Moeller, Benjamin C; Doyle-Eisele, Melanie; Kracko, Dean; Bodnar, Wanda M; Starr, Thomas B; Swenberg, James A

    2015-07-01

    Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N(2-)hydroxymethyl-dG (N(2)-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N(2)-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [(13)CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N(2)-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency's Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair. © The Author 2015

  17. Relation between Mechanical Properties and Pyrolysis Temperature of Phenol Formaldehyde Resin for Gas Separation Membranes

    Czech Academy of Sciences Publication Activity Database

    Šupová, Monika; Svítilová, Jaroslava; Chlup, Zdeněk; Černý, Martin; Weishauptová, Zuzana; Suchý, Tomáš; Machovič, Vladimír; Sucharda, Zbyněk; Žaloudková, Margit

    2012-01-01

    Roč. 56, č. 1 (2012), s. 40-49 ISSN 0862-5468 R&D Projects: GA ČR GA203/09/1327 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z20410507 Keywords : glassy carbon * membranes * mechanical properties Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.418, year: 2012 http://www.ceramics-silikaty.cz/2012/pdf/2012_01_40.pdf

  18. Endogenous Formaldehyde Is a Hematopoietic Stem Cell Genotoxin and Metabolic Carcinogen

    Science.gov (United States)

    Pontel, Lucas B.; Rosado, Ivan V.; Burgos-Barragan, Guillermo; Garaycoechea, Juan I.; Yu, Rui; Arends, Mark J.; Chandrasekaran, Gayathri; Broecker, Verena; Wei, Wei; Liu, Limin; Swenberg, James A.; Crossan, Gerry P.; Patel, Ketan J.

    2015-01-01

    Summary Endogenous formaldehyde is produced by numerous biochemical pathways fundamental to life, and it can crosslink both DNA and proteins. However, the consequences of its accumulation are unclear. Here we show that endogenous formaldehyde is removed by the enzyme alcohol dehydrogenase 5 (ADH5/GSNOR), and Adh5−/− mice therefore accumulate formaldehyde adducts in DNA. The repair of this damage is mediated by FANCD2, a DNA crosslink repair protein. Adh5−/−Fancd2−/− mice reveal an essential requirement for these protection mechanisms in hematopoietic stem cells (HSCs), leading to their depletion and precipitating bone marrow failure. More widespread formaldehyde-induced DNA damage also causes karyomegaly and dysfunction of hepatocytes and nephrons. Bone marrow transplantation not only rescued hematopoiesis but, surprisingly, also preserved nephron function. Nevertheless, all of these animals eventually developed fatal malignancies. Formaldehyde is therefore an important source of endogenous DNA damage that is counteracted in mammals by a conserved protection mechanism. PMID:26412304

  19. Circulating immune/inflammation markers in Chinese workers occupationally exposed to formaldehyde

    Science.gov (United States)

    Seow, Wei Jie; Zhang, Luoping; Vermeulen, Roel; Tang, Xiaojiang; Hu, Wei; Bassig, Bryan A.; Ji, Zhiying; Shiels, Meredith S.; Kemp, Troy J.; Shen, Min; Qiu, Chuangyi; Reiss, Boris; Beane Freeman, Laura E.; Blair, Aaron; Kim, Christopher; Guo, Weihong; Wen, Cuiju; Li, Laiyu; Pinto, Ligia A.; Huang, Hanlin; Smith, Martyn T.; Hildesheim, Allan; Rothman, Nathaniel; Lan, Qing

    2015-01-01

    Background. Formaldehyde has been classified as a human myeloid leukemogen. However, the mechanistic basis for this association is still debated. Objectives. We aimed to evaluate whether circulating immune/inflammation markers were altered in workers occupationally exposed to formaldehyde. Methods. Using a multiplexed bead-based assay, we measured serum levels of 38 immune/inflammation markers in a cross-sectional study of 43 formaldehyde-exposed and 51 unexposed factory workers in Guangdong, China. Linear regression models adjusting for potential confounders were used to compare marker levels in exposed and unexposed workers. Results. We found significantly lower circulating levels of two markers among exposed factory workers compared with unexposed controls that remained significant after adjusting for potential confounders and multiple comparisons using a false discovery rate of 10%, including chemokine (C-X-C motif) ligand 11 (36.2 pg/ml in exposed versus 48.4 pg/ml in controls, P = 0.0008) and thymus and activation regulated chemokine (52.7 pg/ml in exposed versus 75.0 pg/ml in controls, P = 0.0028), suggesting immunosuppression among formaldehyde-exposed workers. Conclusions. Our findings are consistent with recently emerging understanding that immunosuppression might be associated with myeloid diseases. These findings, if replicated in a larger study, may provide insights into the mechanisms by which formaldehyde promotes leukemogenesis. PMID:25908645

  20. Formaldehyde exposure and its effects during pregnancy: Recommendations for laboratory attendance based on available data.

    Science.gov (United States)

    Haffner, Matthew J; Oakes, Peter; Demerdash, Amin; Yammine, Kaissar Cesar; Watanabe, Koichi; Loukas, Marios; Tubbs, R Shane

    2015-11-01

    Formalin is commonly used in fixation of cadaveric specimens. Exposure to formaldehyde, a component of formalin and a known carcinogen, during gross anatomy laboratory dissection is a continuing concern for pregnant students and instructors. Since there is little literature on this specific topic, the current review was compiled in the hope of offering recommendations to pregnant students and instructors who are engaged in human anatomical dissection where formalin is used. Relevant articles were obtained through searches of PubMed and Google Scholar for the terms "formaldehyde," "pregnant," "formalin," and "exposure." A literature search was conducted for chemical information and articles about exposure as issued by government regulatory agencies and chemical companies that produce formaldehyde. This led to the compilation of 29 articles each of which included references to previous, relevant, human research. The reviewed literature contains data strongly suggesting that pregnancy can be affected by formaldehyde exposure. Therefore, on the basis our analysis, female students who might be pregnant should avoid formaldehyde exposure, including that in a gross anatomy laboratory. Instructors should find other means of ensuring anatomical competence for these students. © 2015 Wiley Periodicals, Inc.

  1. Formaldehyde Crosses the Human Placenta and Affects Human Trophoblast Differentiation and Hormonal Functions

    Science.gov (United States)

    Pidoux, Guillaume; Gerbaud, Pascale; Guibourdenche, Jean; Thérond, Patrice; Ferreira, Fatima; Simasotchi, Christelle; Evain-Brion, Danièle; Gil, Sophie

    2015-01-01

    The chorionic villus of the human placenta is the source of specific endocrine functions and nutrient exchanges. These activities are ensured by the syncytiotrophobast (ST), which bathes in maternal blood. The ST arises and regenerates throughout pregnancy by fusion of underlying cytotrophoblasts (CT). Any anomaly of ST formation or regeneration can affect pregnancy outcome and fetal growth. Because of its direct interaction with maternal blood, the ST is sensitive to drugs, pollutants and xenohormones. Ex vivo assays of perfused cotyledon show that formaldehyde, a common pollutant present in furniture, paint and plastics, can accumulate in the human placenta and cross to the fetal compartment. By means of RT-qPCR, immunoblot and immunocytochemistry experiments, we demonstrate in vitro that formaldehyde exerts endocrine toxicity on human trophoblasts, including a decrease in the production of protein hormones of pregnancy. In addition, formaldehyde exposure triggered human trophoblast fusion by upregulating syncitin-1 receptor expression (ASC-type amino-acid transporter 2: ASCT2). Moreover, we show that formaldehyde-exposed trophoblasts present an altered redox status associated with oxidative stress, and an increase in ASCT2 expression intended to compensate for this stress. Finally, we demonstrate that the adverse effects of formaldehyde on trophoblast differentiation and fusion are reversed by N-acetyl-L-cysteine (Nac), an antioxidant. PMID:26186596

  2. Age-related formaldehyde interferes with DNA methyltransferase function, causing memory loss in Alzheimer's disease.

    Science.gov (United States)

    Tong, Zhiqian; Han, Chanshuai; Qiang, Min; Wang, Weishan; Lv, Jihui; Zhang, Shouzi; Luo, Wenhong; Li, Hui; Luo, Hongjun; Zhou, Jiangning; Wu, Beibei; Su, Tao; Yang, Xu; Wang, Xiaomin; Liu, Ying; He, Rongqiao

    2015-01-01

    Hippocampus-related topographic amnesia is the most common symptom of memory disorders in Alzheimer's disease (AD) patients. Recent studies have revealed that experience-mediated DNA methylation, which is regulated by enzymes with DNA methyltransferase (DNMT) activity, is required for the formation of recent memory as well as the maintenance of remote memory. Notably, overexpression of DNMT3a in the hippocampus can reverse spatial memory deficits in aged mice. However, a decline in global DNA methylation was found in the autopsied hippocampi of patients with AD. Exactly, what endogenous factors that affect DNA methylation still remain to be elucidated. Here, we report a marked increase in endogenous formaldehyde levels is associated with a decline in global DNA methylation in the autopsied hippocampus from AD patients. In vitro and in vivo results show that formaldehyde in excess of normal physiological levels reduced global DNA methylation by interfering DNMTs. Interestingly, intrahippocampal injection of excess formaldehyde before spatial learning in healthy adult rats can mimic the learning difficulty of early stage of AD. Moreover, injection of excess formaldehyde after spatial learning can mimic the loss of remote spatial memory observed in late stage of AD. These findings suggest that aging-associated formaldehyde contributes to topographic amnesia in AD patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Formaldehyde and heavy metal migration from rubber and metallic packaging/utensils in Korea.

    Science.gov (United States)

    Kim, Su-Un; Kim, Tae-Rang; Lee, Eun-Soon; Kim, Mi-Sun; Kim, Chang-Kyu; Kim, Li-Ra; Shin, Gi-Young

    2015-01-01

    The aim of this study was to determine the non-intentionally added substances--formaldehyde and trace metals--at 4% acetic acid conditions in rubber and metallic packaging/utensils. The temperature effect on migration in rubber and metallic packaging/utensils was monitored at 60 °C and 100 °C under acidic (pH formaldehyde--23.1 μg kg⁻¹, lead--13.41 μg kg⁻¹, cadmium--0.15 μg kg⁻¹, total arsenic--2.02 μg kg⁻¹ and nickel--2.92 μg kg⁻¹ at 60 °C and formaldehyde--148.9 μg kg⁻¹, lead--17.04 μg kg⁻¹, cadmium--0.14 μg kg⁻¹, total arsenic--7.25 μg kg⁻¹ and nickel--8.7 μg kg⁻¹ at 100 °C. A significant difference was noticed in formaldehyde and total arsenic between both temperatures (p formaldehyde and total arsenic were more sensitive with cooking temperature than the other metals.

  4. A Potentiometric Formaldehyde Biosensor Based on Immobilization of Alcohol Oxidase on Acryloxysuccinimide-modified Acrylic Microspheres

    Directory of Open Access Journals (Sweden)

    Lee Yook Heng

    2010-11-01

    Full Text Available A new alcohol oxidase (AOX enzyme-based formaldehyde biosensor based on acrylic microspheres has been developed. Hydrophobic poly(n-butyl acrylate-N-acryloxy-succinimide [poly(nBA-NAS] microspheres, an enzyme immobilization matrix, was synthesized using photopolymerization in an emulsion form. AOX-poly(nBA-NAS microspheres were deposited on a pH transducer made from a layer of photocured and self-plasticized polyacrylate membrane with an entrapped pH ionophore coated on a Ag/AgCl screen printed electrode (SPE. Oxidation of formaldehyde by the immobilized AOX resulted in the production of protons, which can be determined via the pH transducer. Effects of buffer concentrations, pH and different amount of immobilization matrix towards the biosensor’s analytical performance were investigated. The formaldehyde biosensor exhibited a dynamic linear response range to formaldehyde from 0.3–316.2 mM and a sensitivity of 59.41 ± 0.66 mV/decade (R2 = 0.9776, n = 3. The lower detection limit of the biosensor was 0.3 mM, while reproducibility and repeatability were 3.16% RSD (relative standard deviation and 1.11% RSD, respectively (n = 3. The use of acrylic microspheres in the potentiometric formaldehyde biosensor improved the biosensor’s performance in terms of response time, linear response range and long term stability when compared with thick film immobilization methods.

  5. Respiratory symptoms and functional impairments induced by occupational exposure to formaldehyde

    Directory of Open Access Journals (Sweden)

    AR Choobineh

    2010-07-01

    Full Text Available Background and aimsThe main purpose of this study was to assess the acute and chronic effects of occupational exposure to low levels of formaldehyde on respiratory health.MethodsThis historical cohort study was conducted at a local melamine-formaldehyde resin producing plant. The study population consisted of seventy exposed and 24 non-exposed (referent employees. In this study, a questionnaire was used to evaluate and determined the prevalence of respiratory symptoms. Atmospheric concentrations of formaldehyde were measured at different areas of the plant. Similarly, using a spirometer, the parameters of pulmonary function were measured during exposure and a few days after exposure ceased.ResultsAtmospheric concentrations of formaldehyde marginally exceeded current permissible levels. Additionally, significant decrements in some parameters of pulmonary function, both during and after exposure were noted. However, a relative recovery in lungfunctional capacity observed following temporary cessation of exposure. Furthermore, exposed workers had higher prevalencerates of regular cough, wheezing, phlegm, shortness of breath, chest tightness and episodes of chest illness associated with cold.ConclusionThe findings of this study indicate that exposure to formaldehyde may induce respiratory symptoms, acute partially reversible and chronic irreversible functional impairments of the lungs.

  6. Effect of Thermal Treatment of Veneer on Formaldehyde Emission of Poplar Plywood

    Directory of Open Access Journals (Sweden)

    Takato Nakano

    2013-01-01

    Full Text Available A large amount of poplar plywood is now being imported into Japan from China, and as a result, formaldehyde emitted from this plywood represents an undesirable chemical that must be controlled using a chemical catching agent. The aim of this study is to find an approach to reduce the formaldehyde emission of poplar plywood using thermal treatment without employing any chemicals. The experimental results obtained show that heating veneer sheets in the temperature range of 150 °C to 170 °C effectively reduced the formaldehyde emission of plywood, without diminishing the mechanical properties of the veneer. By applying Langmuir’s theory and Hailwood-Horrobin theory to the adsorption isotherm obtained in this study, the relationship between the formaldehyde emission of plywood and the adsorption properties of veneer as a material is discussed. When veneer sheets were heated in the temperature range of 150 °C to 170 °C, the amount of hydrated water (monomolecular layer decreased slightly and that of dissolved water (polymolecular layer did not change. It is hypothesized that the formaldehyde emission of plywood is related to the condition of the adsorption site of the wood.

  7. Community interest and feasibility of using a novel smartphone-based formaldehyde exposure detection technology.

    Science.gov (United States)

    Castner, Jessica; Gehrke, Gretchen E; Shapiro, Nicholas; Dannemiller, Karen C

    2018-01-11

    This study is the first community engagement phase of a project to develop a residential formaldehyde detection system. The objectives were to conduct a feasibility assessment for device use, and identify factors associated with concerns about environmental exposure and community interest in this device. A cross-sectional, internet-based survey employing community-based participatory research principles was utilized. 147 individuals participated from a focused Waycross, Georgia (58.5%) and broader national sample (41.5%). Variables included acceptable cost and number of testing samples, interest in conducting tests, levels of concern over pollutants, health status, housing, and demographics. The majority of participants desired a system with fewer than 10 samples at ≤$15.00 per sample. Statistically significant higher levels of concern over air quality, formaldehyde exposure, and interest in testing formaldehyde were observed for those with overall worse health status and living in the Waycross, Georgia geographic region. Significant differences in formaldehyde testing interest were observed by health status (OR = 0.31, 95% CI = 0.12-0.81 for home testing) and geographic location (OR = 3.16, 95% CI = 1.22-8.14 for home and OR = 4.06, 95% CI = 1.48-11.12 for ambient testing) in multivariate models. Geographic location and poorer general health status were associated with concerns over and interest in formaldehyde testing. © 2018 Wiley Periodicals, Inc.

  8. Formaldehyde Production From Isoprene Oxidation Across NOx Regimes

    Science.gov (United States)

    Wolfe, G. M.; Kaiser, J.; Hanisco, T. F.; Keutsch, F. N.; de Gouw, J. A.; Gilman, J. B.; Graus, M.; Hatch, C. D.; Holloway, J.; Horowitz, L. W.; hide

    2016-01-01

    The chemical link between isoprene and formaldehyde (HCHO) is a strong, non-linear function of NOx (= NO + NO2). This relationship is a linchpin for top-down isoprene emission inventory verification from orbital HCHO column observations. It is also a benchmark for overall photochemical mechanism performance with regard to VOC oxidation. Using a comprehensive suite of airborne in situ observations over the southeast US, we quantify HCHO production across the urban-rural spectrum. Analysis of isoprene and its major first-generation oxidation products allows us to define both a prompt yield of HCHO (molecules of HCHO produced per molecule of freshly emitted isoprene) and the background HCHO mixing ratio (from oxidation of longer-lived hydrocarbons). Over the range of observed NOx values (roughly 0.1 - 2 ppbv), the prompt yield increases by a factor of 3 (from 0.3 to 0.9 ppbv ppbv(exp. -10), while background HCHO increases by a factor of 2 (from 1.6 to 3.3 ppbv). We apply the same method to evaluate the performance of both a global chemical transport model (AM3) and a measurement-constrained 0-D steady-state box model. Both models reproduce the NOx dependence of the prompt HCHO yield, illustrating that models with updated isoprene oxidation mechanisms can adequately capture the link between HCHO and recent isoprene emissions. On the other hand, both models underestimate background HCHO mixing ratios, suggesting missing HCHO precursors, inadequate representation of later-generation isoprene degradation and/or underestimated hydroxyl radical concentrations. Detailed process rates from the box model simulation demonstrate a 3-fold increase in HCHO production across the range of observed NOx values, driven by a 100% increase in OH and a 40% increase in branching of organic peroxy radical reactions to produce HCHO.

  9. Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde. II. The Large Magellanic Cloud

    Science.gov (United States)

    Tang, X. D.; Henkel, C.; Chen, C.-H. R.; Menten, K. M.; Indebetouw, R.; Zheng, X. W.; Esimbek, J.; Zhou, J. J.; Yuan, Y.; Li, D. L.; He, Y. X.

    2017-04-01

    Context. The kinetic temperature of molecular clouds is a fundamental physical parameter affecting star formation and the initial mass function. The Large Magellanic Cloud (LMC) is the closest star-forming galaxy with a low metallicity and provides an ideal laboratory for studying star formation in such an environment. Aims: The classical dense molecular gas thermometer NH3 is seldom available in a low-metallicity environment because of photoionization and a lack of nitrogen atoms. Our goal is to directly measure the gas kinetic temperature with formaldehyde toward six star-forming regions in the LMC. Methods: Three rotational transitions (JKAKC = 303-202, 322-221, and 321-220) of para-H2CO near 218 GHz were observed with the Atacama Pathfinder EXperiment (APEX) 12 m telescope toward six star-forming regions in the LMC. These data are complemented by C18O 2-1 spectra. Results: Using non-local thermal equilibrium modeling with RADEX, we derive the gas kinetic temperature and spatial density, using as constraints the measured para-H2CO 321-220/303-202 and para-H2CO 303-202/C18O 2-1 ratios. Excluding the quiescent cloud N159S, where only one para-H2CO line could be detected, the gas kinetic temperatures derived from the preferred para-H2CO 321-220/303-202 line ratios range from 35 to 63 K with an average of 47 ± 5 K (errors are unweighted standard deviations of the mean). Spatial densities of the gas derived from the para-H2CO 303-202/C18O 2-1 line ratios yield 0.4-2.9 × 105 cm-3 with an average of 1.5 ± 0.4 × 105 cm-3. Temperatures derived from the para-H2CO line ratio are similar to those obtained with the same method from Galactic star-forming regions and agree with results derived from CO in the dense regions (n(H2) > 103 cm-3) of the LMC. A comparison of kinetic temperatures derived from para-H2CO with those from the dust also shows good agreement. This suggests that the dust and para-H2CO are well mixed in the studied star-forming regions. A comparison of

  10. Effect of an ozone-generating air-purifying device on reducing concentrations of formaldehyde in air

    Energy Technology Data Exchange (ETDEWEB)

    Esswein, E.J. [Univ. of Utah School of Medicine, Salt Lake City, UT (United States); Boeniger, M.F. [National Institute for Occupational Safety, Cincinnati, OH (United States)

    1994-02-01

    Formaldehyde, an air contaminant found in many indoor air investigations, poses distinct occupational exposure hazards in certain job categories (e.g., mortuary science) but is also of concern when found or suspected in office buildings and homes. A variety of air-purifying devices (APDs) are currently available or marketed for application to reduce or remove concentrations of a variety of indoor air pollutants through the use of ozone as a chemical oxidant. An investigation was conducted to determine if concentrations of formaldehyde similar to those found in industrial hygiene evaluations of funeral homes could be reduced with the use of an ozone-generating APD. An ozone-generating APD was placed in an exposure chamber and formaldehyde-containing embalming solution was allowed to evaporate naturally, creating peak and mean chamber concentrations of 2.5 and 1.3 ppm, respectively. Continuous-reading instruments were used to sample for formaldehyde and ozone. Active sampling methods were also used to sample simultaneously for formaldehyde and a possible reactant product, formic acid. Triplicate measurements were made in each of three evaluations: formaldehyde alone, ozone alone, and formaldehyde and ozone combined. Concentrations of formaldehyde were virtually identical with and without 0.5 ppm ozone. No reduction in formaldehyde concentration was found during a 90-minute evaluation using ozone at this concentration with peak and average concentrations of approximately 2.5 and 1.3 ppm formaldehyde, respectively. The results of this investigation suggest that the use of ozone is ineffective in reducing concentrations of formaldehyde. Because ozone has demonstrated health hazards, and is a regulated air contaminant in both the occupational and ambient environment, the use of ozone as an air purification agent in indoor air does not seem warranted. 25 refs., 5 figs., 4 tabs.

  11. Purification and characterization of an NAD+-linked formaldehyde dehydrogenase from the facultative RuMP cycle methylotroph Arthrobacter P1

    NARCIS (Netherlands)

    Attwood, Margaret M.; Arfman, Nico; Weusthuis, Ruud A.; Dijkhuizen, Lubbert

    1992-01-01

    When Arthrobacter P1 is grown on choline, betaine, dimethylglycine or sarcosine, an NAD+-dependent formaldehyde dehydrogenase is induced. This formaldehyde dehydrogenase has been purified using ammonium sulphate fractionation, anion exchange- and hydrophobic interaction chromatography. The molecular

  12. Determination of free formaldehyde in cosmetics containing formaldehyde-releasing preservatives by reversed-phase dispersive liquid-liquid microextraction and liquid chromatography with post-column derivatization.

    Science.gov (United States)

    Miralles, Pablo; Chisvert, Alberto; Alonso, M José; Hernandorena, Sandra; Salvador, Amparo

    2018-03-30

    An analytical method for the determination of traces of formaldehyde in cosmetic products containing formaldehyde-releasing preservatives has been developed. The method is based on reversed-phase dispersive liquid-liquid microextraction (RP-DLLME), that allows the extraction of highly polar compounds, followed by liquid chromatography-ultraviolet/visible (LC-UV/vis) determination with post-column derivatization. The variables involved in the RP-DLLME process were studied to provide the best enrichment factors. Under the selected conditions, a mixture of 500 μL of acetonitrile (disperser solvent) and 50 μL of water (extraction solvent) was rapidly injected into 5 mL of toluene sample solution. The extracts were injected into the LC-UV/vis system using phosphate buffer 6 mmol L -1 at pH 2 as mobile phase. After chromatographic separation, the eluate merged with a flow stream of pentane-2,4-dione in ammonium acetate solution as derivatizing reagent and passed throughout a post-column reactor at 85 °C in order to derivatize formaldehyde into 3,5-diacetyl-1,4-dihydrolutidine, according to Hantzsch reaction, which was finally measured spectrophotometrically at 407 nm. The method was successfully validated showing good linearity, an enrichment factor of 86 ± 2, limits of detection and quantification of 0.7 and 2.3 ng mL -1 , respectively, and good repeatability (RSD < 9.2%). Finally, the proposed analytical method was applied to the determination of formaldehyde in different commercial cosmetic samples containing formaldehyde-releasing preservatives, such as bronopol, diazolidinyl urea, imidazolidinyl urea, and DMDM hydantoin, with good relative recovery values (91-113%) thus showing that matrix effects were negligible. The good analytical features of the proposed method besides of its simplicity and affordability, make it useful to carry out the quality control of cosmetic products containing formaldehyde-releasing preservatives. Copyright

  13. Impact of endophytic colonization patterns on Zamioculcas zamiifolia stress response and in regulating ROS, tryptophan and IAA levels under airborne formaldehyde and formaldehyde-contaminated soil conditions.

    Science.gov (United States)

    Khaksar, Gholamreza; Treesubsuntorn, Chairat; Thiravetyan, Paitip

    2017-05-01

    Deeper understanding of plant-endophyte interactions under abiotic stress would provide new insights into phytoprotection and phytoremediation enhancement. Many studies have investigated the positive role of plant-endophyte interactions in providing protection to the plant against pollutant stress through auxin (indole-3-acetic acid (IAA)) production. However, little is known about the impact of endophytic colonization patterns on plant stress response in relation to reactive oxygen species (ROS) and IAA levels. Moreover, the possible effect of pollutant phase on plant stress response is poorly understood. Here, we elucidated the impact of endophytic colonization patterns on plant stress response under airborne formaldehyde compared to formaldehyde-contaminated soil. ROS, tryptophan and IAA levels in the roots and shoots of endophyte-inoculated and non-inoculated plants in the presence and absence of formaldehyde were measured. Strain-specific quantitative polymerase chain reaction (qPCR) was used to investigate dynamics of endophyte colonization. Under the initial exposure to airborne formaldehyde, non-inoculated plants accumulated more tryptophan in the shoots (compared to the roots) to synthesize IAA. However, endophyte-inoculated plants behaved differently as they synthesized and accumulated more tryptophan in the roots and, hence, higher levels of IAA accumulation and exudation within roots which might act as a signaling molecule to selectively recruit B. cereus ERBP. Under continuous airborne formaldehyde stress, higher levels of ROS accumulation in the shoots pushed the plant to synthesize more tryptophan and IAA in the shoots (compared to the roots). Higher levels of IAA in the shoots might act as the potent driving force to relocalize B. cereus ERBP from roots to the shoots. In contrast, under formaldehyde-contaminated soil, B. cereus ERBP colonized root tissues without moving to the shoots since there was a sharp increase in ROS, tryptophan and IAA

  14. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to formaldehyde and non-formaldehyde biocides in semi-synthetic metalworking fluids.

    Science.gov (United States)

    Selvaraju, Suresh B; Khan, Izhar U H; Yadav, Jagjit S

    2011-01-20

    Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP) in machine workers exposed to contaminated metalworking fluid (MWF). This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO) biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone) and Preventol CMK 40 (phenolic) toward this emerging mycobacterial species (M. immunogenum) in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B). Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2-1600 fold) than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A) led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  15. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to Formaldehyde and Non-Formaldehyde Biocides in Semi-Synthetic Metalworking Fluids

    Directory of Open Access Journals (Sweden)

    Suresh B. Selvaraju

    2011-01-01

    Full Text Available Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP in machine workers exposed to contaminated metalworking fluid (MWF. This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone and Preventol CMK 40 (phenolic toward this emerging mycobacterial species (M. immunogenum in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B. Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2–1600 fold than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  16. Genetic engineering of baker's and wine yeasts using formaldehyde hyperresistance-mediating plasmids

    Directory of Open Access Journals (Sweden)

    M. Schmidt

    1997-12-01

    Full Text Available Yeast multi-copy vectors carrying the formaldehyde-resistance marker gene SFA have proved to be a valuable tool for research on industrially used strains of Saccharomyces cerevisiae. The genetics of these strains is often poorly understood, and for various reasons it is not possible to simply subject these strains to protocols of genetic engineering that have been established for laboratory strains of S. cerevisiae. We tested our vectors and protocols using 10 randomly picked baker's and wine yeasts all of which could be transformed by a simple protocol with vectors conferring hyperresistance to formaldehyde. The application of formaldehyde as a selecting agent also offers the advantage of its biodegradation to CO2 during fermentation, i.e., the selecting agent will be consumed and therefore its removal during down-stream processing is not necessary. Thus, this vector provides an expression system which is simple to apply and inexpensive to use

  17. [Observational study of formaldehyde in air, rain and fog water at a site on the Mangdang Mountain of Fujian, China].

    Science.gov (United States)

    Wang, Xiao-yan; Wang, Hui-xiang; Ma, Yi-yuan

    2010-08-01

    Through 2,4-dinitrophenylhydrazine (DNPH) high-performance liquid chromatography (HPLC) method, the levels of formaldehyde in ambient air, rain and fog samples were measured in Mangdang Mountain, Fujian Province, from March to April 2009. The average concentrations of formaldehyde in ambient air, rain and fog are 4.0 x 10(-10), 2.19 micromol/L and 2.94 micromol/L, respectively. Based on previous researches, this study described formaldehyde hydrolysis and reacting with S(IV) and other chemical reaction processes in liquid phase, explaining the phenomenon that the solubility of formaldehyde in the liquid phase is higher than the theoretical value. On-site measured Henry coefficients (Hme) and the effective Henry coefficients (H*) were derived from concentration of formaldehyde in ambient air, rain and fog samples and references. Comparing Hme and H*, this study found that the measured liquid phase concentrations of formaldehyde are higher than the theoretical concentrations, consistent with the references. The further founding is that Hme/H* in fog is higher than in rain, proving the result of Mangdang Mountain that the concentration of formaldehyde in fog is higher than in rain. Considering the climatic characteristics of Mangdang Mountain in spring, the wet deposition of formaldehyde is an important way in this area.

  18. Multicenter Patch Testing With a Resol Resin Based on Phenol and Formaldehyde Within the International Contact Dermatitis Research Group

    DEFF Research Database (Denmark)

    Isaksson, M.; Ale, I.; Andersen, Klaus Ejner

    2015-01-01

    .2%) reacted to PFR-2. Of those 28 individuals, one had a positive reaction to formaldehyde and 2 to p-tertiary-butylphenol-formaldehyde resin. Simultaneous allergic reactions were noted to colophonium in 3, to Myroxylon pereirae in 5, and to fragrance mix I in 8. Conclusions The contact allergy frequency...

  19. Effects of Endogenous Formaldehyde in Nasal Tissues on Inhaled Formmaldehyde Dosimetry Predictions in the Rat, Monkey, and Human Nasal Passages

    Science.gov (United States)

    ABSTRACT Formaldehyde, a nasal carcinogen, is also an endogenous compound that is present in all living cells. Due to its high solubility and reactivity, quantitative risk estimates for inhaled formaldehyde rely on internal dose calculations in the upper respiratory tract which ...

  20. Hydroxymethylation beyond Carbonylation: Enantioselective Iridium Catalyzed Reductive Coupling of Formaldehyde with Allylic Acetates via Enantiotopic ?-Facial Discrimination

    OpenAIRE

    Garza, Victoria J.; Krische, Michael J.

    2016-01-01

    Chiral iridium complexes modified by SEGPHOS catalyze the 2-propanol mediated reductive coupling of branched allylic acetates 1a?1o with formaldehyde to form primary homoallylic alcohols 2a?2o with excellent control of regio- and enantioselectivity. These processes, which rely on enantiotopic ?-facial discrimination of ?-allyliridium intermediates, represent the first examples of enantioselective formaldehyde C-C coupling beyond aldol addition.

  1. THE EFFECT OF FORMALDEHYDE EXPOSURE AND YOGURT SUPPLEMENTATION ON PROFILE AND CHARACTER OF HEPAR TISSUE PROTEIN OF RATS (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    Chanif Mahdi

    2010-06-01

    Full Text Available Formaldehyde is a simplest organic compound of aldehyde or alkanal group. Formaldehyde is a toxic and carcinogenic substance. Formaldehyde contamination through food or feeding diet continuously is very dangerous for the body, especially for bodies organ for instances likes hepar and kidney. Because formaldehyde is sources of reactive oxygen species (ROS and free radicals substances for the body. This purpose of the study is to know the effect of formaldehyde exposure and yogurt supplementation on profile and characters of rats (Rattus norvegicus protein hepar tissues. The research methods is laboratory methods. The protein profiles determined by electrophoresis (SDS-PAGE methods. The character of hepar protein tissue determined by ELISA, Dot Blot and Western Blot methods. The result showed that formaldehyde exposure through the feeding diet of rats affect on profile of hepar protein tissue, that characterized by appear of new band of specific protein with molecule weigh is 29.6 kDa (PSForm 29.6. Yogurt supplementation on rat that exposure by formaldehyde through the feeding diet of rat, that characterized by expressing of new band of specific protein with relative molecule weight 24.8 kDa (PSYogh 24.8 kDa, and followed by depressed or dispear of protein specific band of 29.6 kDa(PSForm 29.6 kDa. The result showed that isolated protein PSForm 29.6 kDa have a antigenecity character.   Keywords: Formaldehyde exposure, yogurt, ROS, profile and protein character

  2. Second-generation method for analysis of chromatin binding with formaldehyde-cross-linking kinetics.

    Science.gov (United States)

    Zaidi, Hussain; Hoffman, Elizabeth A; Shetty, Savera J; Bekiranov, Stefan; Auble, David T

    2017-11-24

    Formaldehyde-cross-linking underpins many of the most commonly used experimental approaches in the chromatin field, especially in capturing site-specific protein-DNA interactions. Extending such assays to assess the stability and binding kinetics of protein-DNA interactions is more challenging, requiring absolute measurements with a relatively high degree of physical precision. We previously described an experimental framework called the cross-linking kinetics (CLK) assay, which uses time-dependent formaldehyde-cross-linking data to extract kinetic parameters of chromatin binding. Many aspects of formaldehyde behavior in cells are unknown or undocumented, however, and could potentially affect CLK data analyses. Here, we report biochemical results that better define the properties of formaldehyde-cross-linking in budding yeast cells. These results have the potential to inform interpretations of "standard" chromatin assays, including chromatin immunoprecipitation. Moreover, the chemical complexity we uncovered resulted in the development of an improved method for measuring binding kinetics with the CLK approach. Optimum conditions included an increased formaldehyde concentration and more robust glycine-quench conditions. Notably, we observed that formaldehyde-cross-linking rates can vary dramatically for different protein-DNA interactions in vivo Some interactions were cross-linked much faster than the in vivo macromolecular interactions, making them suitable for kinetic analysis. For other interactions, we found the cross-linking reaction occurred on the same time scale or slower than binding dynamics; for these interactions, it was sometimes possible to compute the in vivo equilibrium-binding constant but not binding on- and off-rates. This improved method yields more accurate in vivo binding kinetics estimates on the minute time scale. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Treatment of marine sewage pumpout and RV park pumpout wastewater containing high strength concentrations of formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Salonich, J. [Venturi Aeration Inc., Pelham, New Hampshire (United States)

    2002-06-15

    'Full text:' A consortium of companies has developed an integrated 'on-site' wastewater treatment technology that is capable of handling and degrading RV Park and Marine Sewage Pumpout Wastes which contain formaldehyde [35 - 80 mg/L]. Boat and RV owners add formaldehyde to their toilets to eliminate odors. When these materials are pumped out they are high in solids content and have high concentrations of HCHO, which makes them difficult to degrade at POTWs. At the heart of this process is 1. An aeration tank with a Venturi Aerator totally external to the tank and 2. The addition of a blend of cultured bacteria that have selected for their ability to degrade formaldehyde. For a complete 'on-site' treatment system Bioclere Trickling Filters can follow this aeration/bacterial treatment system. This is an ideal system configuration for remote locations (RV Parks) or for fresh water lake Marinas looking to reduce their disposal costs and for groundwater discharge with no adverse effect on water quality. Until the development of the formaldehyde degrading bacteria for an industrial wastewater process there were no cultures commercially available specifically for degrading formaldehyde. The most commonly used bacteria were pseudomonas strains for carbohydrate or hydrocarbon wastewater extracted from activated sludge plants. And since formaldehyde is infinitely soluble in a liquid it is difficult to degrade or mineralize. The process in an activated sludge WWTP plant took over 72 hours. With the newly selected consortia of cultures, HCHO can be degraded in 12-14 hours on a batch basis. This is accomplished in a uniquely configured aeration tank where the 'environment' of the tank is constantly conditioned by a Venturi Aerator which strips carbon dioxide generated by the aerobes to maintain a neutral pH, and provide high levels of DO (>5.0 mg/L) to keep the process aerobic. (author)

  4. Treatment of marine sewage pumpout and RV park pumpout wastewater containing high strength concentrations of formaldehyde

    International Nuclear Information System (INIS)

    Salonich, J.

    2002-01-01

    'Full text:' A consortium of companies has developed an integrated 'on-site' wastewater treatment technology that is capable of handling and degrading RV Park and Marine Sewage Pumpout Wastes which contain formaldehyde [35 - 80 mg/L]. Boat and RV owners add formaldehyde to their toilets to eliminate odors. When these materials are pumped out they are high in solids content and have high concentrations of HCHO, which makes them difficult to degrade at POTWs. At the heart of this process is 1. An aeration tank with a Venturi Aerator totally external to the tank and 2. The addition of a blend of cultured bacteria that have selected for their ability to degrade formaldehyde. For a complete 'on-site' treatment system Bioclere Trickling Filters can follow this aeration/bacterial treatment system. This is an ideal system configuration for remote locations (RV Parks) or for fresh water lake Marinas looking to reduce their disposal costs and for groundwater discharge with no adverse effect on water quality. Until the development of the formaldehyde degrading bacteria for an industrial wastewater process there were no cultures commercially available specifically for degrading formaldehyde. The most commonly used bacteria were pseudomonas strains for carbohydrate or hydrocarbon wastewater extracted from activated sludge plants. And since formaldehyde is infinitely soluble in a liquid it is difficult to degrade or mineralize. The process in an activated sludge WWTP plant took over 72 hours. With the newly selected consortia of cultures, HCHO can be degraded in 12-14 hours on a batch basis. This is accomplished in a uniquely configured aeration tank where the 'environment' of the tank is constantly conditioned by a Venturi Aerator which strips carbon dioxide generated by the aerobes to maintain a neutral pH, and provide high levels of DO (>5.0 mg/L) to keep the process aerobic. (author)

  5. Gene expression profiling in lung tissues from rats exposed to formaldehyde.

    Science.gov (United States)

    Sul, Donggeun; Kim, Hyunsook; Oh, Eunha; Phark, Sohee; Cho, Eunkyung; Choi, Seonyoung; Kang, Hyung-Sik; Kim, Eun-Mi; Hwang, Kwang-Woo; Jung, Woon-Won

    2007-08-01

    Formaldehyde is a ubiquitous toxic organic compound recently classified as a carcinogen by the International Agency for Research on Cancer and one of the major factors causing sick building syndrome. In this study, we have investigated the effects of formaldehyde on mRNA expression in rat lung tissues by applying genomics. Rats were exposed to ambient air and two different concentrations of formaldehyde (0, 5, 10 ppm) for 2 weeks at 6 h/day and 5 days/week in an inhalation chamber. Malondialdehyde (MDA) assay and carbonyl spectrometric assay were conducted to determine lipid peroxidation and protein oxidation levels and Comet assays were used for genotoxicity evaluation. Level of MDA, carbonyl insertion and DNA damage in the lungs of rats exposed to FA were found to be dose dependently increased. Gene expression was evaluated by using a bio-array hybridization analysis. A total of 21 (2 up- and 19 down-regulated) genes were identified as biomarkers for formaldehyde effects. Several differentiated gene groups were found. Genes involved in apoptosis, immunity, metabolism, signal transduction, transportation, coagulation and oncogenesis were found to be up- and down-regulated. Among these genes, the mRNA expressions of cytochrome P450, hydroxymethylbilane synthase, glutathione reductase, carbonic anhydrase 2, natriuretic peptide receptor 3, lysosomal associated protein transmembrane 5, regulator of G-protein signaling 3, olfactomedin related ER localized protein, and poly (ADP-ribose) polymerase-1 were confirmed by quantitative RT-PCR analysis. In summary, the MDA lipid peroxidation and the carbonyl protein oxidation assays showed that cytotoxic effects increased with increasing formaldehyde levels. Genomic analysis showed that 21 genes were up- or down-regulated. Of these genes, nine were confirmed by quantitative RT-PCR and could be potential biomarkers for human diseases associated with formaldehyde exposure.

  6. Mortality From Lymphohematopoietic Malignancies and Brain Cancer Among Embalmers Exposed to Formaldehyde

    Science.gov (United States)

    Hauptmann, Michael; Stewart, Patricia A.; Lubin, Jay H.; Hornung, Richard W.; Herrick, Robert F.; Hoover, Robert N.; Fraumeni, Joseph F.; Blair, Aaron; Hayes, Richard B.

    2009-01-01

    Background Excess mortality from lymphohematopoietic malignancies, in particular myeloid leukemia, and brain cancer has been found in surveys of anatomists, pathologists, and funeral industry workers, all of whom may have worked with formaldehyde. We investigated the relation of mortality to work practices and formaldehyde exposure levels among these professionals to address cancer risk in the funeral industry. Methods Professionals employed in the funeral industry who died between January 1, 1960, and January 1, 1986, from lymphohematopoietic malignancies (n = 168) or brain tumors (n = 48) (ie, case subjects) were compared with deceased matched control subjects (n = 265) with regard to lifetime work practices and exposures in the funeral industry, which were obtained by interviews with next of kin and coworkers, and to estimated levels of formaldehyde exposure. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by use of logistic regression. All statistical tests were two-sided. Results Mortality from myeloid leukemia increased statistically significantly with increasing number of years of embalming (P for trend = .020) and with increasing peak formaldehyde exposure (P for trend = .036). Compared with subjects who performed fewer than 500 lifetime embalmings, mortality from myeloid leukemia was elevated among those who performed embalmings for more than 34 years (OR = 3.9, 95% CI = 1.2 to 12.5, P = .024), who performed more than 3068 embalmings (OR = 3.0, 95% CI = 1.0 to 9.2, P = .057), and those whose estimated cumulative formaldehyde exposure exceeded 9253 parts per million–hours (OR = 3.1; 95% CI = 1.0 to 9.6, P = .047). These exposures were not related to other lymphohematopoietic malignancies or to brain cancer. Conclusion Duration of embalming practice and related formaldehyde exposures in the funeral industry were associated with statistically significantly increased risk for mortality from myeloid leukemia. PMID:19933446

  7. Health Risk Assessment of Inhalation Exposure to Formaldehyde and Benzene in Newly Remodeled Buildings, Beijing

    Science.gov (United States)

    Huang, Lihui; Mo, Jinhan; Sundell, Jan; Fan, Zhihua; Zhang, Yinping

    2013-01-01

    Objective To assess health risks associated with inhalation exposure to formaldehyde and benzene mainly emitted from building and decoration materials in newly remodeled indoor spaces in Beijing. Methods We tested the formaldehyde and benzene concentrations in indoor air of 410 dwellings and 451 offices remodeled within the past year, in which the occupants had health concerns about indoor air quality. To assess non-carcinogenic health risks, we compared the data to the health guidelines in China and USA, respectively. To assess carcinogenic health risks, we first modeled indoor personal exposure to formaldehyde and benzene using the concentration data, and then estimated the associated cancer risks by multiplying the indoor personal exposure by the Inhalation Unit Risk values (IURs) provided by the U.S. EPA Integrated Risk Information System (U.S. EPA IRIS) and the California Office of Environmental Health Hazard Assessment (OEHHA), respectively. Results (1) The indoor formaldehyde concentrations of 85% dwellings and 67% offices were above the acute Reference Exposure Level (REL) recommended by the OEHHA and the concentrations of all tested buildings were above the chronic REL recommended by the OEHHA; (2) The indoor benzene concentrations of 12% dwellings and 32% offices exceeded the reference concentration (RfC) recommended by the U.S. EPA IRIS; (3) The median cancer risks from indoor exposure to formaldehyde and benzene were 1,150 and 106 per million (based on U.S. EPA IRIS IURs), 531 and 394 per million (based on OEHHA IURs). Conclusions In the tested buildings, formaldehyde exposure may pose acute and chronic non-carcinogenic health risks to the occupants, whereas benzene exposure may pose chronic non-carcinogenic risks to the occupants. Exposure to both compounds is associated with significant carcinogenic risks. Improvement in ventilation, establishment of volatile organic compounds (VOCs) emission labeling systems for decorating and refurbishing materials

  8. The Formation of Formaldehyde on Interstellar Carbonaceous Grain Analogs by O/H Atom Addition

    Science.gov (United States)

    Potapov, Alexey; Jäger, Cornelia; Henning, Thomas; Jonusas, Mindaugas; Krim, Lahouari

    2017-09-01

    An understanding of possible scenarios for the formation of astrophysically relevant molecules, particularly complex organic molecules, will bring us one step closer to the understanding of our astrochemical heritage. In this context, formaldehyde is an important molecule as a precursor of methanol, which in turn is a starting point for the formation of more complex organic species. In the present experiments, for the first time, following the synthesis of CO, formaldehyde has been produced on the surface of interstellar grain analogs, hydrogenated fullerene-like carbon grains, by O and H atom bombardment. The formation of H2CO is an indication for a possible methanol formation route in such systems.

  9. Effect of Temperature on Electrical Conductivity of Guaiacol-Guanidine Hydrochloride-Formaldehyde Copolymer Resin

    Science.gov (United States)

    Kukade, S. D.; Bawankar, S. V.

    2018-02-01

    The purpose of the present paper is to report temperature dependence of electrical conductivity on Guaiacol-guanidine hydrochloride-formaldehyde copolymer resin. By using a microwave irradiation technique, various ratios of copolymer resin were synthesized from the reacting monomers, i.e., guaiacol, guanidine hydrochloride and formaldehyde. The characterization of the copolymer resins has been fulfilled by spectral methods viz. ultraviolet visible (UV visible), infrared and proton nuclear magnetic spectroscopy (1H-NMR). The solid state direct current electrical conductivity of synthesized copolymer resins has been measured as a function of temperature. The electrical conductivity values of all the copolymers have been found in the range of a semiconductor.

  10. A theoretical study of the reaction of lithium aluminum hydride with formaldehyde and cyclohexanone.

    Science.gov (United States)

    Luibrand, R T; Taigounov, I R; Taigounov, A A

    2001-11-02

    Geometries and energies of the reactants, complexes, and transition states for the reactions of lithium aluminum hydride with formaldehyde and cyclohexanone were obtained using ab initio and density functional (Becke3LYP/6-31G**) molecular orbital calculations. Two pathways for reaction with formaldehyde and four transition states corresponding to axial and equatorial attack at cyclohexanone were located. The transition state structures had reactant-like geometries. Predicted stereoselectivity of the reduction of cyclohexanone strongly favors axial approach of hydrogen, in agreement with experimental data. Analysis of the transition state structures suggests that electronic effects are more important than torsional effects in controlling stereoselectivity.

  11. Mechanistic and dose considerations for supporting adverse pulmonary physiology in response to formaldehyde

    International Nuclear Information System (INIS)

    Thompson, Chad M.; Subramaniam, Ravi P.; Grafstroem, Roland C.

    2008-01-01

    Induction of airway hyperresponsiveness and asthma from formaldehyde inhalation exposure remains a debated and controversial issue. Yet, recent evidences on pulmonary biology and the pharmacokinetics and toxicity of formaldehyde lend support for such adverse effects. Specifically, altered thiol biology from accelerated enzymatic reduction of the endogenous bronchodilator S-nitrosoglutathione and pulmonary inflammation from involvement of Th2-mediated immune responses might serve as key events and cooperate in airway pathophysiology. Understanding what role these mechanisms play in various species and lifestages (e.g., child vs. adult) could be crucial for making more meaningful inter- and intra-species dosimetric extrapolations in human health risk assessment

  12. Synthesis, Characterization and Mechanical Evaluation of the Phenol-Formaldehyde Composites

    Directory of Open Access Journals (Sweden)

    B. S. Kaith

    2008-01-01

    Full Text Available Phenol: formaldehyde ratio was varied in the synthesis of phenol- formaldehyde resin and used to prepare the composites. These composites were then evaluated for their mechanical strength on the basis of tensile strength, compressive strength and wear resistance. Composite with better strength was characterized by IR, SEM, XRD, TGA/DTA and further studies were carried out for its physico-chemical and mechanical properties like viscosity, modulus of rupture (MOR, modulus of elasticity (MOE and stress at the limit of proportionality (SP etc.

  13. Investigation of the detoxification mechanism of formaldehyde-treated tetanus toxin

    DEFF Research Database (Denmark)

    Thaysen-Andersen, Morten; Jørgensen, Sys Borcher; Wilhelmsen, Ellen Sloth

    2007-01-01

    %) of the known TeNT sequence, including the active site, was covered using the off-line LC-MS approach to investigate the tryptic digested TTd. In contrast to the results obtained from the gel-electrophoretic experiments, neither intra/inter-chain cross-links nor cross-links to external lysines were observed...... the lysine or formaldehyde concentration was Gel-electrophoretic analyses showed that inter-chain cross-linking was formaldehyde-dependent and, furthermore, revealed that inter-chain cross-linking was not the only requirement for the inactivation...

  14. Evaluation of the physical, mechanical properties and formaldehyde emission of particleboard manufactured from waste stone pine (Pinus pinea L.) cones.

    Science.gov (United States)

    Buyuksari, Umit; Ayrilmis, Nadir; Avci, Erkan; Koc, Enus

    2010-01-01

    The objective of this study was to investigate some physical/mechanical properties and formaldehyde emission of particleboard containing particles of waste stone pine cone at various usage ratios using urea-formaldehyde resin. Some physical (thickness swelling, water absorption), mechanical (modulus of elasticity, modulus of rupture, internal bond strength) properties and formaldehyde emission of particleboards were evaluated. The addition of cone particle improved water resistance of the panels and greatly reduced their formaldehyde emissions. However, flexural properties and internal bond strength decreased with increasing cone particle content in the panel. The cone of the stone pine can be considered as an alternative to wood material in the manufacture of particleboard used in indoor environment due to lower thickness swelling, water absorption and formaldehyde emission.

  15. Implications of mechanical deformation and formaldehyde preservation for the identification of stage-specific characteristics of Baltic cod eggs

    DEFF Research Database (Denmark)

    Geldmacher, A.; Wieland, Kai

    1999-01-01

    The identification of developmental stages in fish eggs from plankton samples is often complicated by deformation of the embryos due to mechanical stress during the sampling procedure and by dehydration during formaldehyde fixation. The effects of formaldehyde fixation and mechanical stress on Ba...... mechanically deformed during handling were clearly distinguishable from those that died prior to catching; however, staging was generally less accurate for formaldehyde- preserved eggs when compared with living specimens.......The identification of developmental stages in fish eggs from plankton samples is often complicated by deformation of the embryos due to mechanical stress during the sampling procedure and by dehydration during formaldehyde fixation. The effects of formaldehyde fixation and mechanical stress...... on Baltic cod eggs (Gadus morhua callarias L.) were examined separately by visually comparing the morphological features of treated vs. live eggs of identical ontogenetic age. Microphotographs were made concurrently for documentation. In stage IA eggs, mechanical treatment resulted in scattered blastodiscs...

  16. Meridional distribution of hydroperoxides and formaldehyde in the marine boundary layer of the Atlantic (48°N-35°S) measured during the Albatross campaign

    Science.gov (United States)

    Weller, R.; Schrems, O.; Boddenberg, A.; GäB, S.; Gautrois, M.

    2000-06-01

    Gas phase H2O2, organic peroxides, and formaldehyde (HCHO) have been measured in situ during October/November 1996 on board RV Polarstern in surface air over the Atlantic from 48°N-35°S with different analytical methods. The results indicate that recombination and self-reactions of peroxy radicals largely dominate over scavenging by NO. The peroxy radical chemistry was governed by the photooxidation of CH4 and CO, as could be deduced from our failure to detect organic hydroperoxides other than CH3OOH (methyl hydroperoxide (MHP)). Hydroperoxide and formaldehyde mixing ratios were highest within the tropics with peak values of around 2000 parts per trillion by volume (pptv) (H2O2), 1500 pptv (MHP), and 1000 pptv (HCHO). In the case of H2O2 and MHP we observed diurnal variations of the mixing ratios in the tropical North Atlantic and derived deposition rates of around (1.8±0.6)×10-5 s-1 for H2O2 and (1.2±0.4)×10-5 s-1 for MHP. The measured MHP/(H2O2+MHP) and MHP/HCHO ratios corresponded to 0.32±0.12 and 0.87±0.4, respectively. HCHO mixing ratios observed during the expedition were significantly higher than predicted by current photochemical theory based on the photooxidation of CH4 and CO.

  17. An axis-specific rotational rainbow in the direct scatter of formaldehyde from Au(111) and its influence on trapping probability.

    Science.gov (United States)

    Park, G Barratt; Krüger, Bastian C; Meyer, Sven; Kandratsenka, Alexander; Wodtke, Alec M; Schäfer, Tim

    2017-08-02

    The conversion of translational to rotational motion often plays a major role in the trapping of small molecules at surfaces, a crucial first step for a wide variety chemical processes that occur at gas-surface interfaces. However, to date most quantum-state resolved surface scattering experiments have been performed on diatomic molecules, and little detailed information is available about how the structure of nonlinear polyatomic molecules influences the mechanisms for energy exchange with surfaces. In the current work, we employ a new rotationally resolved 1 + 1' resonance-enhanced multiphoton ionization (REMPI) scheme to measure the rotational distribution in formaldehyde molecules directly scattered from the Au(111) surface at incidence kinetic energies in the range 0.3-1.2 eV. The results indicate a pronounced propensity to excite a-axis rotation (twirling) rather than b- or c-axis rotation (tumbling or cartwheeling), and are consistent with a rotational rainbow scattering model. Classical trajectory calculations suggest that the effect arises-to zeroth order-from the three-dimensional shape of the molecule (steric effects). Analysis suggests that the high degree of rotational excitation has a substantial influence on the trapping probability of formaldehyde at incidence translational energies above 0.5 eV.

  18. Fire emissions constrained by the synergistic use of formaldehyde and glyoxal SCIAMACHY columns in a two-compound inverse modelling framework

    Science.gov (United States)

    Stavrakou, T.; Muller, J.; de Smedt, I.; van Roozendael, M.; Vrekoussis, M.; Wittrock, F.; Richter, A.; Burrows, J.

    2008-12-01

    Formaldehyde (HCHO) and glyoxal (CHOCHO) are carbonyls formed in the oxidation of volatile organic compounds (VOCs) emitted by plants, anthropogenic activities, and biomass burning. They are also directly emitted by fires. Although this primary production represents only a small part of the global source for both species, yet it can be locally important during intense fire events. Simultaneous observations of formaldehyde and glyoxal retrieved from the SCIAMACHY satellite instrument in 2005 and provided by the BIRA/IASB and the Bremen group, respectively, are compared with the corresponding columns simulated with the IMAGESv2 global CTM. The chemical mechanism has been optimized with respect to HCHO and CHOCHO production from pyrogenically emitted NMVOCs, based on the Master Chemical Mechanism (MCM) and on an explicit profile for biomass burning emissions. Gas-to-particle conversion of glyoxal in clouds and in aqueous aerosols is considered in the model. In this study we provide top-down estimates for fire emissions of HCHO and CHOCHO precursors by performing a two- compound inversion of emissions using the adjoint of the IMAGES model. The pyrogenic fluxes are optimized at the model resolution. The two-compound inversion offers the advantage that the information gained from measurements of one species constrains the sources of both compounds, due to the existence of common precursors. In a first inversion, only the burnt biomass amounts are optimized. In subsequent simulations, the emission factors for key individual NMVOC compounds are also varied.

  19. An Engineering Evaluation of Spherical Resorcinol Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Birdwell Jr, Joseph F [ORNL; Lee, Denise L [ORNL; Taylor, Paul Allen [ORNL; Collins, Robert T [ORNL; Hunt, Rodney Dale [ORNL

    2010-09-01

    A small column ion exchange (SCIX) system has been proposed for removal of cesium from caustic, supernatant, and dissolved salt solutions stored or generated from high-level tank wastes at the US Department of Energy (DOE) Hanford Site and Savannah River Sites. In both instances, deployment of SCIX systems, either in-tank or near-tank, is a means of expediting waste pretreatment and dispositioning with minimal or no new infrastructure requirements. Conceptually, the treatment approach can utilize a range of ion exchange media. Previously, both crystalline silicotitanate (CST), an inorganic, nonelutable sorbent, and resorcinol-formaldehyde (RF), an organic, elutable resin, have been considered for cesium removal from tank waste. More recently, Pacific Northwest National Laboratory (PNNL) evaluated use of SuperLig{reg_sign} 644, an elutable ion exchange medium, for the subject application. Results of testing indicate hydraulic limitations of the SuperLig{reg_sign} resin, specifically a high pressure drop through packed ion exchange columns. This limitation is likely the result of swelling and shrinkage of the irregularly shaped (granular) resin during repeated conversions between sodium and hydrogen forms as the resin is first loaded then eluted. It is anticipated that a similar flow limitation would exist in columns packed with conventional, granular RF resin. However, use of spherical RF resin is a likely means of mitigating processing limitations due to excessive pressure drop. Although size changes occur as the spherical resin is cycled through loading and elution operations, the geometry of the resin is expected to effectively mitigate the close packing that leads to high pressure drops across ion exchange columns. Multiple evaluations have been performed to determine the feasibility of using spherical RF resin and to obtain data necessary for design of an SCIX process. The work performed consisted of examination of radiation effects on resin performance

  20. FORMALDEHYDE MASERS: EXCLUSIVE TRACERS OF HIGH-MASS STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Araya, E. D.; Brown, J. E. [Western Illinois University, Physics Department, 1 University Circle, Macomb, IL 61455 (United States); Olmi, L. [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Ortiz, J. Morales [University of Puerto Rico, Río Piedras Campus, Physical Sciences Department, P.O. Box 23323, San Juan, PR 00931 (United States); Hofner, P.; Creech-Eakman, M. J. [New Mexico Institute of Mining and Technology, Physics Department, 801 Leroy Place, Socorro, NM 87801 (United States); Kurtz, S. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3-72, 58089 Morelia, Michoacán (Mexico); Linz, H. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)

    2015-11-15

    The detection of four formaldehyde (H{sub 2}CO) maser regions toward young high-mass stellar objects in the last decade, in addition to the three previously known regions, calls for an investigation of whether H{sub 2}CO masers are an exclusive tracer of young high-mass stellar objects. We report the first survey specifically focused on the search for 6 cm H{sub 2}CO masers toward non high-mass star-forming regions (non HMSFRs). The observations were conducted with the 305 m Arecibo Telescope toward 25 low-mass star-forming regions, 15 planetary nebulae and post-AGB stars, and 31 late-type stars. We detected no H{sub 2}CO emission in our sample of non HMSFRs. To check for the association between high-mass star formation and H{sub 2}CO masers, we also conducted a survey toward 22 high-mass star-forming regions from a Hi-GAL (Herschel infrared Galactic Plane Survey) sample known to harbor 6.7 GHz CH{sub 3}OH masers. We detected a new 6 cm H{sub 2}CO emission line in G32.74−0.07. This work provides further evidence that supports an exclusive association between H{sub 2}CO masers and young regions of high-mass star formation. Furthermore, we detected H{sub 2}CO absorption toward all Hi-GAL sources, and toward 24 low-mass star-forming regions. We also conducted a simultaneous survey for OH (4660, 4750, 4765 MHz), H110α (4874 MHz), HCOOH (4916 MHz), CH{sub 3}OH (5005 MHz), and CH{sub 2}NH (5289 MHz) toward 68 of the sources in our sample of non HMSFRs. With the exception of the detection of a 4765 MHz OH line toward a pre-planetary nebula (IRAS 04395+3601), we detected no other spectral line to an upper limit of 15 mJy for most sources.

  1. Behavioral sensitization after repeated formaldehyde exposure in rats.

    Science.gov (United States)

    Sorg, B A; Hochstatter, T

    1999-01-01

    Multiple chemical sensitivity (MCS) is a phenomenon whereby individuals report increased sensitivity to chemicals in the environment, and attribute their sensitivities to prior exposure to the same or often structurally unrelated chemicals. A leading hypothesis suggests that MCS is akin to behavioral sensitization observed in rodents after repeated exposure to drugs of abuse or environmental stressors. Sensitization occurring within limbic circuitry of the central nervous system (CNS) may explain the multisymptom complaints in individuals with MCS. The present studies represent the continuing development of an animal model for MCS, the basis of which is the CNS sensitization hypothesis. Three behaviors were assessed in rats repeatedly exposed to formaldehyde (Form) inhalation. In the first series of experiments, rats were given high-dose Form exposure (11 parts per million [ppm]; 1 h/day x 7 days) or low-dose Form exposure (1 ppm; either 1 h/day x 7 days or 1 h/day x 5 days/week x 4 weeks). Within a few days after discontinuing daily Form, cocaine-induced locomotor activity was elevated after high-dose Form or 20 days of low-dose Form inhalation. Approximately 1 month later, cocaine-induced locomotor activity remained significantly elevated in the 20-day Form-exposed rats. The second experiment assessed whether prior exposure to Form (20 days, as above) would alter the ability to condition to an odor (orange oil) paired with footshock. The results suggested a tendency to increase the conditioned fear response to the odor but not the context of the footshock box, and a decreased tendency to extinguish the conditioned fear response to odor. The third experiment examined whether CNS sensitization to daily cocaine or stress would alter subsequent avoidance responding to odor (Form). Daily cocaine significantly elevated approach responses to Form, while daily stress pretreatment produced a trend in the opposite direction, producing greater avoidance of Form. Preliminary

  2. Regulation of methylamine and formaldehyde metabolism in Arthrobacter P1. Effect of pulse-wise addition of "heterotrophic" substrates to C1 substrate-limited continuous cultures

    NARCIS (Netherlands)

    Croes, L.M.; Tiesma, L.; Dijkhuizen, L.

    1986-01-01

    The regulation of methylamine and formaldehyde metabolism in Arthrobacter P1 was investigated in carbon-limited continuous cultures. To avoid toxic effects of higher formaldehyde concentrations, formaldehyde-limited cultures were established in smooth substrate transitions from choline-limitation.

  3. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  4. Gas density gradient for three dark interstellar clouds

    International Nuclear Information System (INIS)

    Fulkerson, S.A.; Clark, F.O.

    1984-01-01

    A grid of models has been constructed of the surface brightness of selected transitions of interstellar formal-dehyde for three interstellar clouds. The grid included radial gas density gradients over a considerable range from uniform to very steep. The model results were then compared to observations of the interstellar dark clouds B361, L183, and L134. In all three cases, the comparison indicates that the gas is centrally condensed and follows a gradient in density which closely approximates an inverse square law. This result offers a hint that the dust may be more centrally condensed than the gas in B361

  5. Gas and Gas Pains

    Science.gov (United States)

    ... Gas and gas pains Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  6. Bra-associated allergic contact dermatitis: p-tert-butylphenol formaldehyde resin as the culprit.

    Science.gov (United States)

    Herro, Elise M; Friedlander, Sheila F; Jacob, Sharon E

    2012-01-01

    P-tert-butylphenol formaldehyde resin (PTBPFR) is recognized as a significant source of allergic contact dermatitis in adults and children in association with athletic gear, shoes, and neoprene. To our knowledge, this is the first case report of allergic contact dermatitis with PTBPFR associated with padded foam bras. © 2011 Wiley Periodicals, Inc.

  7. 75 FR 30825 - Draft Toxicological Review of Formaldehyde in Support of Summary Information on the Integrated...

    Science.gov (United States)

    2010-06-02

    ... independent scientific peer review of the EPA draft human health assessment of formaldehyde. The peer review....aspx?key=49207 ). The public comment period and NAS scientific peer review are separate processes that... draft assessment solely for the purpose of pre-dissemination peer review under applicable information...

  8. Exposition by inhalation to the formaldehyde in the air. Source, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the formaldehyde concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  9. 78 FR 52567 - Formaldehyde Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2013-08-23

    ... (throat). Formaldehyde solutions can damage the skin and burn the eyes. The standard specifies a number of....1048). OMB Control Number: 1218-0145. Affected Public: Business or other for-profits. Number of... and dates of birth. Although all submissions are listed in the http://www.regulations.gov index, some...

  10. [LC-MS/MS analysis of determination of strychnine and brucine in formaldehyde fixed tissue].

    Science.gov (United States)

    Zhan, Lan-fen; Liu, Ming-dong; Yan, You-yi; Ye, Yi; Wang, Wei; Wang, Zhi-hui; Zhao, Jun-hong; Liao, Lin-chuan

    2012-10-01

    To establish a method for determination of strychnine and brucine in formaldehyde fixed tissue by LC-MS/MS analysis. The samples were pretreated with solid phase extraction using SCX cartridges and separated on SB-C18 column with mobile phase 0.1% formic acid : 0.1% formic acid-acetonitrile (75:25). Electrospray ionization (ESI) source was utilized and operated in positive ion mode. Multiple reactions monitoring (MRM) mode was applied. External standard method was applied for quantitation. The chromatographic separation of strychnine and brucine in formaldehyde fixed nephritic and hepatic tissues resulted successfully. The standard curve was linear in the range of 0.002-2.0 microg/g for strychnine and brucine in formaldehyde fixed tissues, and the correlation coefficient was more than 0.996. The limits of detection (LOD) of strychnine and brucine in nephritic tissues were 0.06ng/g and 0.03 ng/g, respectively. The LOD of both chemicals were 0.3 ng/g in hepatic tissues. The extraction recovery rate was more than 74.5%. The precision of intra-day and inter-day were both less than 8.2%. Strychnine and brucine can be sensitive to be determined in formaldehyde fixed tissue by LC-MS/MS analysis. It can be applied in the forensic toxicological analysis.

  11. Intracavity absorption spectroscopy of formaldehyde from 6230 to 6420 cm(-1)

    NARCIS (Netherlands)

    Fjodorow, Peter; Hellmig, Ortwin; Baev, Valery M.; Levinsky, Howard B.; Mokhov, Anatoli V.

    We apply intracavity absorption spectroscopy for measurements of the absorption spectrum of formaldehyde, CH2O, from 6230 to 6420 cm(-1), of which only a small fraction (6351-6362 cm(-1)) has been recorded elsewhere. The measurements are performed in the cavity of a broadband Er3+-doped fiber laser,

  12. CONTINUOUS FORMALDEHYDE MEASUREMENT SYSTEM BASED ON MODIFIED FOURIER TRANSFORM INFRARED SPECTROSCOPY

    Science.gov (United States)

    EPA is developing advanced open-path and cell-based optical techniques for time-resolved measurement of priority hazardous air pollutants such as formaldehyde (HCHO). Due to its high National Air Toxics Assessment risk factor, there is increasing interest in continuous measuremen...

  13. Toxicity of formaldehyde and acrolein mixtures : in vitro studies using nasal epithelial cells

    NARCIS (Netherlands)

    Cassee, F.R.; Stenhuis, W.S.; Groten, J.P.; Feron, V.J.

    1996-01-01

    In vitro studies with human and rat nasal epithelial cells were carried out to investigate the combined toxicity of formaldehyde and acrolein and the role of aldehyde dehydrogenases in this process. These studies showed that the toxic effect of mixtures of aldehydes was additive. In addition,

  14. Sensory irritation to mixtures of formaldehyde, acrolein, and acetaldehyde in rats

    NARCIS (Netherlands)

    Cassee, F.R.; Arts, J.H.E.; Groten, J.P.; Feron, V.J.

    1996-01-01

    Sensory irritation of formaldehyde (FRM), acrolein (ACR) and acetaldehyde (ACE) as measured by the decrease in breathing frequency (DBF) was studied in male Wistar rats using nose-only exposure. Groups of four rats were exposed to each of the single compounds separately or to mixtures of FRM, ACR

  15. Chromatographic analysis of the reaction of soy flour with formaldehyde and phenol for wood adhesives

    Science.gov (United States)

    Linda F. Lorenz; Charles R. Frihart; James M. Wescott

    2007-01-01

    The desire to make more biobased and lower-cost bonded wood products has led to an interest in replacing some phenol and formaldehyde in wood adhesives with soybean flour. Improved knowledge of the soy protein properties is needed to relate resin chemistry to resin performance before and after wood bonding. To expose the soy protein’s functional groups, it...

  16. Nine years of global hydrocarbon emissions based on source inversion of OMI formaldehyde observations

    NARCIS (Netherlands)

    Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean François; De Smedt, Isabelle; Van Roozendael, Michel; Van Der Werf, Guido R.; Wiedinmyer, Christine; Kaiser, Johannes W.; Sindelarova, Katerina; Guenther, Alex

    2016-01-01

    As formaldehyde (HCHO) is a high-yield product in the oxidation of most volatile organic compounds (VOCs) emitted by fires, vegetation, and anthropogenic activities, satellite observations of HCHO are well-suited to inform us on the spatial and temporal variability of the underlying VOC sources. The

  17. Regional Sources of Atmospheric Formaldehyde and Acetaldehyde, and Implications for Atmospheric Modeling

    Science.gov (United States)

    Formaldehyde and acetaldehyde concentrations over the Eastern half of the United States are simulated with a 3-D air quality model to identify the most important chemical precursors under January and July conditions. We find that both aldehydes primarily result from photochemical...

  18. Investigation of Exposure to Formaldehyde from Preserved Biological Specimens. Status Report.

    Science.gov (United States)

    Consumer Product Safety Commission, Washington, DC.

    This investigation of formaldehyde exposure in school laboratories, where its principal source is from preserved biological specimens, was undertaken because of concern over exposure levels reported in the literature. Information was obtained in two ways. A limited survey of schools was conducted to determine extent of students' use of preserved…

  19. Pressure dependent deuterium fractionation in the formation of molecular hydrogen in formaldehyde photolysis

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Andersen, Vibeke Friis; Skov, Henrik

    2009-01-01

    and 1030 mbar. The relative dissociation rate kHCHO/kHCDO was found to depend strongly on pressure, varying from 1.1±0.1 at 50 mbar to 1.75±0.10 at 1030 mbar. The products of formaldehyde photodissociation are either H2+CO (molecular channel) or HCO+H (radical channel). The partitioning between...

  20. Estimating the spread rate of urea formaldehyde adhesive on birch (Betula pendula Roth) veneer using fluorescence

    Science.gov (United States)

    Toni Antikainen; Anti Rohumaa; Christopher G. Hunt; Mari Levirinne; Mark Hughes

    2015-01-01

    In plywood production, human operators find it difficult to precisely monitor the spread rate of adhesive in real-time. In this study, macroscopic fluorescence was used to estimate spread rate (SR) of urea formaldehyde adhesive on birch (Betula pendula Roth) veneer. This method could be an option when developing automated real-time SR measurement for...

  1. Adsorption of Pb, Cd, Zn, Cu and Hg ions on Formaldehyde and ...

    African Journals Online (AJOL)

    MICHAEL

    The calculated value from Freundlich adsorption parameter (KF) and Langmuir adsorption parameter (qmax) showed that the adsorption capacities of the metal ions are in order of Pb2+ > Cd2+ > Zn2+ > Hg2+. > Cu2+ for formaldehyde modified bean husks and Hg2+ > Cd2+ > Pb2+ > Zn2+ > Cu2+ for pyridine modified ...

  2. [Features of dyslipidemia development and insulin resistance in female workers engaged in methanol and formaldehyde production].

    Science.gov (United States)

    Taranenko, L A

    2013-01-01

    The article covers data on analyzing occupational risk of carbohydrate and lipid metabolism in female workers exosed to methanol and formaldehyde. Findings are that increased contents of the studied chemicals in the air of workplace cause more probable dyslipidemia, insuline resistence in peri-menopausal female workers, these disorders have reliable correlation with occupation.

  3. Study of reaction of benzo-1.4-dioxane with formaldehyde

    International Nuclear Information System (INIS)

    Tashbaev, G.A.; Turdialiev, M.Z.; Amonova, A.V.

    2015-01-01

    Present article is devoted to study of reaction of benzo-1.4-dioxane with formaldehyde. The reaction of oxy methylation of benzo-1.4-dioxane with aldehydes under various conditions was considered. The reaction progress and the purity of obtained products was controlled by means of thin-layer chromatography.

  4. Ethanol-Glycerin Fixation with Thymol Conservation: A Potential Alternative to Formaldehyde and Phenol Embalming

    Science.gov (United States)

    Hammer, Niels; Loffler, Sabine; Feja, Christine; Sandrock, Mara; Schmidt, Wolfgang; Bechmann, Ingo; Steinke, Hanno

    2012-01-01

    Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For…

  5. The effect of pheno-formaldehyde finishing on the properties of ...

    African Journals Online (AJOL)

    This paper examined the effect of catalyst concentration, curing time and temperature on a phenolformaldehyde finished direct dyed cotton. The grey cotton fabric was desized, scoured, bleached and dyed with chlorazol D, a direct dye. Sample of the dyed cotton were subjected to resin finishing using phenol: formaldehyde.

  6. An outbreak of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener

    NARCIS (Netherlands)

    de Wit, F. S.; de Groot, A. C.; Weyland, J. W.; Bos, J. D.

    1988-01-01

    8 cases of contact dermatitis from toluenesulfonamide formaldehyde resin in a nail hardener are presented. Most patients had used nail lacquers containing this resin for many years without trouble, but became sensitized to the resin shortly after the introduction of this particular nail hardener. A

  7. Pressure dependent isotopic fractionation in the photolysis of formaldehyde-d2

    DEFF Research Database (Denmark)

    Nilsson, E.J.K.; Schmidt, Johan Albrecht; Johnson, Matthew Stanley

    2014-01-01

    earlier work with HDCO vs. H2CO. The UV lamps used for photolysis emit light at wavelengths that primarily dissociate formaldehyde into molecular products, CO and H2 or D2. The isotope effect k(H2CO)/k(D2CO) Combining double low line 3.16 ± 0.03 at 1000 mbar is in good agreement...

  8. Resorcinol-formaldehyde reactions in dilute solution observed by carbon-13 NMR spectroscopy

    Science.gov (United States)

    Alfred W. Christiansen

    2000-01-01

    A recently discovered coupling agent, hydroxymethylated resorcinol (HMR), based on resorcinol-formaldehyde, can greatly enhance wood-to-epoxy resin bond durability in exterior applications. However, for HMR to be most effective, it needs to be prepared a few hours before it is applied to the...

  9. Preliminary survey report: control technology for formaldehyde emissions at Jasper Laminates, Jasper, Indiana, October 19, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, V.D.

    1983-07-29

    An onsite visit was made to Jasper Laminates, Jasper, Indiana to observe the processes used in veneering wood panels by a heater platen press method, and methods of controlling formaldehyde emissions. The facility produced panels for pianos, organs, office furniture and other wood products, using primarily the hot press process along with some radiofrequency (RF) pressing of curved panels and small parts. The glue most often used was a urea/formaldehyde resin adhesive. The hot presses were located under one large ventilated enclosure, measuring about 20 by 150 feet. There were also eight ventilation fans in the ceiling and auxiliary fans used to provide additional cooling air for workers and for the caul plates. Therefore, the primary methods of controlling formaldehyde exposure were dispersion, using auxiliary fans, and area ventilation. No partial-shift-time weighted-average formaldehyde concentrations were measured at over 1 part per million (ppm). For two workers unloading different hot presses, short-term breathing-zone concentrations occasionally reached 2 ppm. The author concludes that this facility offers the opportunity to study large-scale area ventilation with passive make-up air supply, and the appropriate use of auxiliary fans.

  10. First Results from the COFFEE Instrument: Airborne In-Situ Measurements of Formaldehyde over California

    Science.gov (United States)

    Iraci, L. T.; St Clair, J.; Marrero, J. E.; Gore, W.; Swanson, A. K.; Hanisco, T. F.

    2015-12-01

    The Compact Formaldehyde Fluorescence Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of formaldehyde as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. COFFEE, developed at NASA-GSFC, has a sensitivity of 100 pptv (1 sec) and can operate over a wide range of altitudes from the boundary layer to the lower stratosphere. It is mounted in an external wing pod on the Alpha Jet aircraft based at NASA-ARC, which can access altitudes from the surface up to 40,000 ft. We will present results from test flights performed in Fall 2015 over the Central Valley of California. Targets include an oil field, agricultural areas, and highways. Formaldehyde is one of the few urban pollutants that can be measured from space, and we will present plans to compare COFFEE in-situ data with space-based formaldehyde observations such as those from OMI (Aura) and OMPS (SuomiNPP).

  11. Preparation and characterization of poly (urea-formaldehyde) walled dicyclopentadiene microcapsules

    NARCIS (Netherlands)

    Xiong, W.; Zhu, G.; Tang, J.; Dong, B.; Han, N.; Xing, F.; Schlangen, H.E.J.G.

    2013-01-01

    Poly (urea-formaldehyde) (PUF) shelled dicyclopentadiene (DCPD) microcapsules were prepared by in-situ polymerization technology for self-healing concrete applications. It’s found, during the process, sodium dodecyl benzene sulfonate (SDBS) behaves better in emulsification of DCPD than other

  12. Phenol-formaldehyde reactivity with lignin in the wood cell wall

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Latewood from Pinus taeda was reacted with alkaline phenol–formaldehyde (PF) adhesive and characterised using two-dimensional 1H–13C solution-state nuclear magnetic resonance (NMR) spectroscopy so that chemical modification of the wood cell wall polymers, after PF resol curing, could be elucidated. The...

  13. CeO2 thin film as a low-temperature formaldehyde sensor in mixed ...

    Indian Academy of Sciences (India)

    Administrator

    Centre for Nanotechnology and Advanced Biomaterials (CeNTAB) and. School of Electrical and Electronics Engineering, SASTRA University, Thanjavur 613 401, India ... a good biomarker for diagnosing lung cancer at an earlier stage (Fuchs et al 2010). Hence, there is a need for formaldehyde detection in diseases ...

  14. Characteristics of urea-formaldehyde resins as related to glue bond quality of southern pine particleboard

    Science.gov (United States)

    C. -Y. Hse

    1974-01-01

    Forty-five urea resins were formulated and replicated by factorial arrangement of three variables: molar ratio of formaldehyde to urea (1.5, 1.7, 1.9, 2.1, and 2.3), reactant concentration (35, 42.5, and 50%), and reaction temperature (75°, 85°, and 95°C).

  15. The Survey of Chemical Paper Pulp Properties Produced from Rice Straw Based on Formaldehyde Sulfide Method.

    Directory of Open Access Journals (Sweden)

    Kamel Mohammadzadeh

    2013-06-01

    Full Text Available The aim of this study was to evaluate the effect of formaldehyde addition to Sodium Sulfide cooking liquor for chemical Pulp Production from rice straw. Rice straw (oryza sativa was collected from the rice field of Salmanshahr and was carried to the laboratory of wood and paper in Gorgan University. Digestion conditions of pulp included cooking temperature of 160 °C, digestion times of 30, 60 and 90 min and useing chemical (16, 18 and, 20% Sodium sulfite and 4 and 6% formaldehyde based on oven dry dosages weight of raw material. Four different treatments, at a Kappa number ranges of 12 - 14 were selected from each pulp In order to evaluate the effect of formaldehyde added based on Kappa number and pulp yield relations. Hand sheets with grammage of 60 g/m2 were prepared from each of pulp samples and their properties were measured using the related Tappi standard. The results indicated that the addetion of formaldehyde in sulfite liquor increased the pulp yield at the same Kappa number, accelerated delignification rate and improved delignification selectiving as well as improving the mechanical properties of paper

  16. Synthesis and cure kinetics of liquefied wood/phenol/formaldehyde resins

    Science.gov (United States)

    Hui Pan; Todd F. Shupe; Chung-Yun Hse

    2008-01-01

    Wood liquefaction was conducted at a 2/1 phenol/wood ratio in two different reactors: (1) an atmospheric three-necked flask reactor and (2) a sealed Parr reactor. The liquefied wood mixture (liquefied wood, unreacted phenol, and wood residue) was further condensed with formaldehyde under acidic conditions to synthesize two novolac-type liquefied wood/phenol/...

  17. Effects of creatine supplementation along with resistance training on urinary formaldehyde and serum enzymes in wrestlers.

    Science.gov (United States)

    Nasseri, Azadeh; Jafari, Afshar

    2016-04-01

    Formaldehyde is a cytotoxic agent produced from creatine through a metabolic pathway, and in this regard, it has been claimed that creatine supplementation could be cytotoxic. Even though the cytotoxic effects of creatine supplementation have been widely studied, yet little is known about how resistance training can alter these toxic effects. This study aimed to determine the effects of short-term creatine supplementation plus resistance training on the level of urinary formaldehyde and concentrations of serum enzymes in young male wrestlers. In a double-blind design twenty-one subjects were randomized into creatine supplementation (Cr), creatine supplementation plus resistance training (Cr + T) and placebo plus resistance training (Pl + T) groups. Participants ingested creatine (0.3 g/kg/day) or placebo for 7 days. The training protocol consisted of 3 sessions in one week, each session including three sets of 6-9 repetitions at 80-85% of one-repetition maximum for whole-body exercise. Urine and blood samples were collected at baseline and at the end of the supplementation. Creatine supplementation significantly increased the excretion rate of urinary formaldehyde in the Cr and Cr + T groups by 63.4% and 30.4%, respectively (P0.05). These findings indicate that resistance training may lower the increase of urinary formaldehyde excretion induced by creatine supplementation, suggesting that creatine consumption could be relatively less toxic when combined with resistance training.

  18. Migration of formaldehyde and melamine monomers from kitchen- and tableware made of melamine plastic

    DEFF Research Database (Denmark)

    Lund, K.H.; Petersen, J.H.

    2006-01-01

    Migration of one or both formaldehyde and/or melamine monomers was found in seven of ten tested melamine samples bought on the Danish market. The samples were a bowl, a jug, a mug, a ladle, and different cups and plates. No violation of the European Union-specific migration limits for melamine (30...

  19. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1460 Melamine... melamine is made to react with not more than 3 moles of formaldehyde in water solution. (b) The resins may... polymerization reaction control agent. Phthalic acid anhydride Do. Zinc stearate For use as lubricant. (c) The...

  20. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Science.gov (United States)

    2010-04-01

    ... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea... urea is made to react with not more than 2 moles of formaldehyde in water solution. (b) The resins may... polymerization-control agent. Tetrachlorophthalic acid anhydride Do. Zinc stearate For use as lubricant. (c) The...