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1

Tunable pulsed carbon dioxide laser  

NASA Technical Reports Server (NTRS)

Transverse electrically-excited-atmosphere (TEA) laser is continuously tunable over several hundred megahertz about centers of spectral lines of carbon dioxide. It is operated in single longitudinal mode (SLM) by injection of beam from continuous-wave, tunable-waveguide carbon dioxide laser, which serves as master frequency-control oscillator. Device measures absorption line of ozone; with adjustments, it is applicable to monitoring of atmospheric trace species.

Megie, G. J.; Menzies, R. T.

1981-01-01

2

Carbon dioxide laser management cervical intraepithelial neoplasia  

Microsoft Academic Search

In this report we describe the use of the carbon dioxide laser for the outpatient management of cervical intraepithelial neoplasia (CIN). A comparison of treatment effectiveness for different grades of CIN is also included. Two hundred fifty-six cases were evaluated by colposcopy, cytology, and histopathology, treated by at least 5 to 6 mm of laser vaporization, and followed up for

J. H. Bellina; V. C. Wright; J. I. Voros; M. A. Riopelle; V. Hohenschutz

1981-01-01

3

Fractional Carbon Dioxide Laser Resurfacing  

PubMed Central

Currently available ablative fractional CO2 lasers provide excellent results and diminish down time with fewer complications than previous generation CO2 lasers. Mechanisms of action, treatment parameters, as well as pre- and postoperative care will be discussed.

Ramsdell, William M.

2012-01-01

4

Pulsed-discharge carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

The purpose is to attempt a general introduction to pulsed carbon dioxide lasers of the kind used or proposed for laser radar applications. Laser physics is an excellent example of a cross-disciplinary topic, and the molecular spectroscopy, energy transfer, and plasma kinetics of the devices are explored. The concept of stimulated emission and population inversions is introduced, leading on to the molecular spectroscopy of the CO2 molecule. This is followed by a consideration of electron-impact pumping, and the pertinent energy transfer and relaxation processes which go on. Since the devices are plasma pumped, it is necessary to introduce a complex subject, but this is restricted to appropriate physics of glow discharges. Examples of representative devices are shown. The implications of the foregoing to plasma chemistry and gas life are discussed.

Willetts, David V.

1990-01-01

5

Numerical analysis of a carbon dioxide SFUR laser.  

National Technical Information Service (NTIS)

Within the framework of the ENEA (Italian Commission for Alternative Energy Sources) project on optical and electro-optical technologies, a TEA carbon dioxide laser was developed based upon a Self Filtering Unstable Resonator (SFUR). It delivers high ener...

R. Barbini, F. Colao, A. Petri

1989-01-01

6

Zenker's Diverticulum: Carbon Dioxide Laser Endoscopic Surgery  

PubMed Central

Nowadays endoscopic diverticulotomy is the surgical approach of the first choice in treatment of Zenker's diverticulum. We report our experience with this procedure and try to sum up recent recommendations for management of surgery and postoperative care. Data of 34 patients with Zenker's diverticulum, treated by endoscopic carbon dioxide laser diverticulotomy at the Department of Otorhinolaryngology and Head and Neck Surgery, 1st Faculty of Medicine, Charles University, University Hospital Motol, Prague, Czech Republic, were prospectively stored and followed in relatively short period from May 2009 to December 2013. The average length of diverticulum was 32?mm. The average duration of surgery was 32?min. The patients were fed via feeding tube for 6.1 days and antibiotics were administered for 7 days. Mean hospitalization time was 7.4 days. We observed one transient recurrent laryngeal nerve paralysis and no other serious complications. Recurrence rate was 3%. We recommend complete transection of the diverticular septum in one procedure, systemic antibiotic treatment and exclusion of transoral intake for minimally 5 days, and contrast oesophagogram before resumption of oral intake to exclude fistula. Open diverticulectomy should be reserved for cases with inadequate endoscopic exposure and for revision surgery for multiple recurrences from endoscopic diverticulotomies.

Plzak, Jan; Zabrodsky, Michal; Lukes, Petr

2014-01-01

7

Carbon dioxide laser oral safety parameters for teeth  

Microsoft Academic Search

The carbon dioxide laser is used in the oral cavity for a variety of procedures. Although the procedures may not involve the teeth directly, precaution should be exercised to preserve their integrity. The results of this study indicate that the most limiting parameter for oral use of the CO laser is damage to the enamel surface, which could be inflicted

G. Lynn Powell; Brian K. Whisenant; Thomas H. Morton

1990-01-01

8

Complications of carbon dioxide laser resurfacing and their prevention  

Microsoft Academic Search

Carbon dioxide laser resurfacing has gained widespread acceptance. Although advances in laser technology have greatly improved this technique and minimized operator error, adverse outcomes and complications still occur. Many of these complications can be readily avoided. In our series of 1925 patients, undesirable outcomes occurred mainly in the early stages of our experience and could be attributed to poor preoperative

Cynthia Weinstein; Jason N. Pozner; Oscar M. Ramirez

1997-01-01

9

21 CFR 179.43 - Carbon dioxide laser for etching food.  

Code of Federal Regulations, 2013 CFR

...THE PRODUCTION, PROCESSING AND HANDLING OF FOOD Radiation and Radiation Sources § 179.43 Carbon dioxide laser for etching...food under the following conditions: (a) The radiation source consists of a carbon dioxide laser...

2013-04-01

10

Superpulsed carbon dioxide laser: an update on cutaneous surgical applications  

NASA Astrophysics Data System (ADS)

Superpulsing the carbon dioxide laser allows delivery of high energy pulses separated by short pauses during which tissue cooling can occur.1 This new technology can provide several important advantages in cutaneous surgery over similar procedures performed with conventional continuous discharge carbon dioxide laser systems. In the excisional mode, there is a two-thirds reduction in thermal necrosis of the wound edge.2 This should translate into more rapid healing3 and increased rate of gain in tensile strength. In the vaporizational mode, precise, superficial and bloodless ablation of multiple benign appendigeal tumors is possible with less thermal damage yielding excellent cosmetic results. The establishment through additional research of accurate laser parameters, pulse duration, peak energy levels, and frequency of pulses, will help improve the specificity of the laser-tissue interaction to provide even better surgical results.

Wheeland, Ronald G.

1990-06-01

11

Carbon dioxide laser trabeculostomy for the treatment of neovascular glaucoma.  

PubMed Central

During the past 18 months, 23 cases of advanced neovascular glaucoma, unresponsive to medical therapy, have been treated by a trabeculostomy procedure using a carbon dioxide laser. This procedure entails surgical entry into the anterior chamber from beneath either a conjunctival or a scleral flap in such a way as to completely cauterize any neovascular tissue in the iridocorneal angle and to permit adequate drainage of the aqueous fluid from the anterior chamber to the periocular space. The average intraocular pressure, prior to carbon dioxide laser trabeculostomy was 54 mm Hg and these pressures were lowered below 18 mm Hg in over 57% of the cases followed for longer than six months post-laser therapy. Treatment was considered a failure in 26% of the cases where the intraocular pressure was not lowered substantially, and 17% of the treated eyes sustained a pressure decrease to within the 25 to 35 mm Hg range. Carbon dioxide laser trabeculostomy or trabeculo-sclerostomy provides a new method of lowering the intraocular pressure in severe cases of neovascular glaucoma without the hazard of intraocular hemorrhage, common with other filtration procedures. These procedures have proved satisfactory in alleviating the high pressures of neovascular glaucoma in a relatively large proportion of the patients treated. If the eye is grossly hyperemic and irritated because of the high intraocular pressure and the deteriorated condition of the eye, it is suggested that the carbon dioxide laser trabeculostomy procedure with a scleral flap be performed with an implanted seton as the procedure of choice. If the eye is relatively quiet and has some visual reserve but an exceedingly high and intractable intraocular pressure, it is advisable to use either the carbon dioxide laser trabeculostomy procedure or the carbon dioxide laser trabeculo-sclerostomy operation as described. These procedures are being further refined, but the results of this investigation suggest that these procedures can be utilized judiciously, and should prove useful, particularly in those eyes with advanced neovascular glaucoma with useful vision still remaining. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 A FIGURE 11 B

L'Esperance, F A; Mittl, R N

1982-01-01

12

Solar pumped continuous wave carbon dioxide laser  

NASA Technical Reports Server (NTRS)

In an effort to demonstrate the feasibility of a solar pumped laser concept, gain has been measured in a CO2-He laser medium optically pumped by blackbody radiation. Various gas mixtures of CO2 and He have been pumped by blackbody radiation emitted from an electrically heated oven. Using a CO2 laser as a probe, an optical gain coefficient of 1.8 x 10 to the -3rd/cm has been measured at 10.6 microns for a 9:1 CO2-He mixture at an oven temperature of about 1500 K, a gas temperature of about 400 K and a pressure of about 1 torr. This corresponds to a small signal gain coefficient when allowance is made for saturation effects due to the probe beam, in reasonable agreement with a theoretical value.

Yesil, O.; Christiansen, W. H.

1978-01-01

13

a Blackbody-Pumped Carbon Dioxide Laser  

NASA Astrophysics Data System (ADS)

A proof of concept experiment has been carried out to demonstrate the feasibility of using blackbody radiation to pump a gas laser. Building on earlier experiments in which optical gain was measured in a CO(,2) laser mixture exposed to blackbody radiation at a temperature of 1500(DEGREES)K, continuous wave oscillation of CO(,2) has been achieved, for the first time, using radiation from a blackbody cavity as the pump source. This was made possible by actively cooling the laser mixture as it was exposed to the radiation field of an electrically heated oven. Output power measurements are presented from a series of experiments using mixtures of CO(,2), He, and Ar. Maximum output power was obtained with a 20%CO(,2) - 15%He- 65%Ar mixture at pressures around 6-10 Torr. The output power was found to vary greatly with the gas temperature and the blackbody temperature. By varying these parameters output powers up to 8 mW have been achieved. The effects of the buffer gas are also shown to be important. Based on the experimental results, it is believed that the buffer gas is needed to inhibit diffusion of the excited species out of the laser mode volume. This diffusion leads to deactivation at the walls. Adding more CO(,2) results in a decrease in output power, indicating that the gas has a finite optical depth and the mode volume is not pumped if too much CO(,2) is present. A model which incorporates these effects is presented. The predicted small signal gains and powers based on this model adequately match the trends observed experimentally.

Insuik, Robin Joy

14

Measurement of Carbon Dioxide Column via Space Borne Laser Absorption  

NASA Technical Reports Server (NTRS)

In order to better understand the budget of carbon dioxide in the Earth's atmosphere it is necessary to develop a global high precision understanding of the carbon dioxide column. In order to uncover the 'missing sink that is responsible for the large discrepancies in the budget as we presently understand it calculation has indicated that measurement accuracy on the order of 1 ppm is necessary. Because typical column average CO2 has now reached 380 ppm this represents a precision on the order of .25% for these column measurements. No species has ever been measured from space at such a precision. In recognition of the importance of understanding the CO2 budget in order to evaluate its impact on global warming the National Research Council in its decadal survey report to NASA recommended planning for a laser based total CO2 mapping mission in the near future. The extreme measurement accuracy requirements on this mission places very strong requirements on the laser system used for the measurement. This work presents an analysis of the characteristics necessary in a laser system used to make this measurement. Consideration is given to the temperature dependence, pressure broadening, and pressure shift of the CO2 lines themselves and how these impact the laser system characteristics Several systems for meeting these requirements that are under investigation at various institutions in the US as well as Europe will be discussed.

Heaps, WIlliam S.

2007-01-01

15

Endonasal carbon-dioxide laser assisted dacryocystorhinostomy verses external dacryocystorhinostomy.  

PubMed

This is a prospective, non-randomized study to evaluate and compare the results, morbidity and surgical time for endonasal carbon-dioxide laser assisted dacryocystorhinostomy and external dacryocystorhinostomy. 70 consecutive patients of chronic dacryocystitis with nasolacrimal duct obstruction were selected for the study. 36 patients under went endonasal CO2 laser assisted dacryocystorhinostomy and 34 had external dacryocystorhinostomy. Selection of the type of operation was left to the patient's choice. All the patients had preoperative counseling and both the procedures were explained in detail with their advantages and disadvantages. Patients not willing for the external incision were selected for endonasal laser assisted dacryocystorhinostomy and others were operated via external approach. Silicone tubes were put in all the patients for three months after surgery. The final follow up was 12 months after the removal of silicone tubes. The patency of the lacrimal passage was confirmed by irrigation, and patients were questioned about their symptoms.The success rates, 12 months after removal of silicone tubes were 100% in endonasal CO2 laser assisted dacryocystorhinostomy and 88.24% in external dacryocystorhinostomy. The surgical time of endonasal laser assisted dacryocystorhinostomy was 38 minutes as compared to 62 in external dacryocystorhinostomy. Complication rate in both groups was almost equal.Thus, we came to the conclusion that Endonasal CO2 laser assisted dacryocystorhinostomy is a better surgical option to external dacryocystorhinostomy in cases of chronic dacryocystitis with nasolacrimal duct obstruction, with shorter surgical time. PMID:23120227

Verma, Ashok; Al Khabori, Mazin; Zutshi, Rajiv

2006-01-01

16

Research of fiber carbon dioxide sensing system based laser absorption spectrum  

NASA Astrophysics Data System (ADS)

Carbon dioxide is one of the important gas need to be detected in coal mine safety. In the mine limited ventilation environment, Concentration of carbon dioxide directly affects the health of coal miners. Carbon dioxide is also one of important signature Gas in spontaneous combustion forecasting of coal goaf area, it is important to accurately detect concentration of carbon dioxide in coal goaf area. This paper proposed a fiber carbon dioxide online sensing system based on tunable diode laser spectroscopy. The system used laser absorption spectroscopy and optical fiber sensors combined, and a near-infrared wavelength 1608nm fiber-coupled distributed feedback laser (DFB) as a light source and a 7cm length gas cell, to achieve a high sensitivity concentration detection of carbon dioxide gas. The technical specifications of sensing system can basically meet the need of mine safety.

Wei, Yubin; Zhang, Tingting; Li, Yanfang; Zhao, Yanjie; Wang, Chang; Liu, Tongyu

2012-01-01

17

Air pollution: sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers.  

PubMed

Detection sensitivities of a few parts per billion for ten gaseous pollutants have been evaluated by measuring the strength of the absorption of infrared radiation from carbon monoxide and carbon dioxide lasers. Ethylene concentrations as small as 5 parts per billion have been detected in air. The measured absorption strengths indicate that in mixtures of pollutants, such as nitrogen dioxide and water vapor, the sensitivity is reduced by overlapping absorption bands. However, calculations indicate that it should be possible to detect nitrogen dioxide concentrations of 0.01 part per million in the presence of water vapor concentrations of 105 parts per million. PMID:5035485

Kreuzer, L B; Kenyon, N D; Patel, C K

1972-07-28

18

Carbon dioxide laser stapedotomy. Thermal effects in the vestibule.  

PubMed

Small-fenestra stapedotomy has recently been popularized in efforts to reduce the incidence of sensorineural hearing loss following stapes surgery for otospongiosis. Lasers have been advocated as a tool to fenestrate the stapes footplate. Conversion of radiant energy from the laser into heat in the vestibule represents the greatest potential risk to the inner ear. Using a carbon dioxide laser with a focal point of 150 microns at 300 mm, fenestrations of the stapes footplate were performed in a series of 14 anesthetized cats. The laser power output ranged from 0.47 to 3.05 W, with pulse durations of 0.2 and 0.5 s. Resultant temperature elevations in the vestibule, measured by a thin-wire thermocouple, ranged from 0 to 4.4 degrees C (0 to 8 degrees F) and directly correlated to wattage and duration of the laser-beam pulse. Temperature changes could be reduced by use of lower wattage, shorter pulse duration, timed intervals between pulses, and convection cooling of the promontory. PMID:3927879

Coker, N J; Ator, G A; Jenkins, H A; Neblett, C R; Morris, J R

1985-09-01

19

Low-fluence carbon dioxide laser irradiation of lentigines  

SciTech Connect

Low-fluence carbon dioxide (CO2) laser irradiation of skin has previously been shown to induce damage limited primarily to the epidermis. To evaluate whether this technique was therapeutically effective for pigmented epidermal lesions, ten lentigines caused by methoxsalen and ultraviolet light therapy were treated in one patient using the CO2 laser at fluences ranging from 3.0 to 7.7 J/cm2 for 0.1-s exposures with 4.5-mm spot size. Based on substantial clearing in seven of ten lesions treated, 146 solar lentigines were treated in five patients at fluences of 3.0, 3.7, or 4.4 J/cm2. Biopsies were performed on a total of 30 lesions immediately and 24 hours, seven days, and six weeks after irradiation. Of 125 lesions followed up clinically for six weeks, 12 cleared completely, 81 lightened substantially, and 28 remained unchanged. Only two demonstrated atrophic change. Hyperpigmentation or hypopigmentation did not occur. All lesions that improved had been treated at 3.7 or 4.4 J/cm2. Immediate histologic injury consisted of vacuolar and spindly change and subsequent vesiculation limited to the basilar epidermis. Twenty-four hours later there was epidermal necrosis with regeneration, 0.1 mm of dermal basophilia and stromal condensation, and a mild inflammatory infiltrate. These alterations were dose-dependent, with near complete epidermal necrosis and superficial dermal involvement at the highest fluence, and only focal epidermal necrosis at the lowest. At seven days, epidermal regeneration was complete with traces of melanin remaining in keratinocytes. Melanophages first appeared at seven days and persisted at six weeks, by which time the inflammatory infiltrate had cleared. No lentiginous proliferation was evident and epidermal pigmentation had become normal. Low-fluence CO2 laser irradiation is an effective means of damaging the epidermis with only minimal dermal change.

Dover, J.S.; Smoller, B.R.; Stern, R.S.; Rosen, S.; Arndt, K.A.

1988-08-01

20

Clinical study on 71 anorectal cases treated by carbon dioxide laser  

NASA Astrophysics Data System (ADS)

This paper describes the effective result of carbon dioxide laser on type I and II internal hemorrhoids, mixed hemorrhoids, anal fissure or fistula, etc. At present, simple hemorrhoidectomy is less acceptable to patients for its excessive bleeding and severe pain during and after the operation. Therefore, the results of 71 anorectal cases of hemorrhoidectomy using carbon dioxide laser have been observed in our hospital. The rates of effective treatment and cure were 100% and 94.3%, respectively.

Li, Gui-hua

1993-03-01

21

Pulsed laser annealing of sodium super ionic conductor for carbon dioxide sensors  

Microsoft Academic Search

This paper discussed a way to improve solid electrolyte carbon dioxide (CO2) sensor by excimer laser annealing of sodium super ionic conductors (NASICON). The CO2 sensor used in this paper consists of a thin NASICON layer. We additionally annealed the NASICON to improve its electrical conductivity by pulsed excimer laser. The laser annealing results in re-crystallization of the NASICON thin

Shi-Chien Kao; Guo-Dung John Su

2010-01-01

22

The NASA high power carbon dioxide laser: A versatile tool for laser applications  

NASA Technical Reports Server (NTRS)

A closed-cycle, continuous wave, carbon dioxide high power laser has been designed and fabricated to support research for the identification and evaluation of possible high power laser applications. The device is designed to generate up to 70 kW of laser power in annular shape beams from 1 to 9 cm in diameter. Electric discharge, either self sustained or electron beam sustained, is used for excitation. This laser facility provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams. The facility provides a well defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

1976-01-01

23

LASCAT - DESIGN OF CATALYTIC MONOLITHS FOR CLOSED-CYCLE CARBON DIOXIDE LASERS  

NASA Technical Reports Server (NTRS)

Pulsed carbon dioxide lasers are useful in many areas, including aeronautics, space research, and weather monitoring. Most applications require a closed-cycle carbon dioxide laser, which is more portable and self-sustaining than an open-cycle system. Without a fresh carbon dioxide supply and provisions for byproduct disposal, the closed-cycle laser must recycle the carbon monoxide and oxygen gas produced by the lasing of carbon dioxide. The recombination of the carbon monoxide and oxygen gas byproducts to form a constant supply of carbon dioxide requires an active catalyst, which must be carefully designed to optimize laser performance in accordance with design requirements specific to the laser's application. LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) aids in the design of the monolith catalyst by simulating the results of design decisions on the performance of the laser. In portable laser systems, considerations of size, weight, and cost are critical. LASCAT provides the opportunity for the designer to explore trade-offs between the catalyst activity, catalyst dimensions, monolith dimensions, pressure drop (a result of gas flow through the monolith), Oxygen gas conversion, and other variables. The program uses a flexible, simplified model of the monolith catalyst designed to determine the bulk-avarage gas temperature, composition, and pressure along its length. The user specifies values for the several parameters which define the catalyst's operating conditions, including monolith dimensions, gas inlet properties, thermal operation properties, and catalyst properties. LASCAT provides results which indicate whether the experimental design meets user-defined constraints such as limits on conversion rate, maximum gas temperature, and monolith weight. LASCAT is written in FORTRAN 77 and is designed for use with any text or character-based terminal or computer display. The program requires roughly 40 KB memory. LASCAT was developed in 1989. LASCAT is restricted for use by United States citizens only.

Guinn, K.

1994-01-01

24

First Airborne Laser Remote Measurements of Atmospheric Carbon Dioxide  

NASA Astrophysics Data System (ADS)

A unique, multi-frequency, single-beam, laser absorption spectrometer (LAS) that operates at 1.57 ?m has been developed for a future space-based mission to determine the global distribution of sources and sinks of atmospheric carbon dioxide (CO2). A prototype of the space-based LAS system was developed by ITT, and it has been successfully flight tested in five airborne campaigns conducted in different geographic regions over the last three years. Flight tests were conducted over Oklahoma, Michigan, New Hampshire, and Virginia under a wide range of atmospheric conditions. Remote LAS measurements were compared to high-quality in situ measurements obtained from instrumentation on the same aircraft on spirals under the ground track of the LAS. LAS flights were conducted over a wide range of land and water reflectances and in the presence of scattered clouds. An extensive data set of CO2 measurements has been obtained for evaluating the LAS performance. LAS CO2 measurements with a signal-to-noise in excess of 250 were obtained for a 1-s average over land and for a 10-s average over water. Absolute comparisons of CO2 remote and in situ measurements showed agreement over a range of altitudes to better than 2 percent. LAS oxygen (O2) measurements, which are needed to convert LAS CO2 density measurements to CO2 mixing ratios (XCO2), have been made in the 1.26-?m region in horizontal ground-based experiments and in initial flight tests. Details of flight test campaigns and measured versus modeled results are presented in this paper.

Browell, E. V.; Dobbs, M. E.; Dobler, J.; Kooi, S.; Choi, Y.; Harrison, F. W.; Moore, B.; Zaccheo, T. S.

2008-12-01

25

Ablative laser resurfacing: high-energy pulsed carbon dioxide and erbium:yttrium-aluminum-garnet  

Microsoft Academic Search

The development of the short-pulsed high-energy carbon dioxide laser in the mid 1990's led to the emergence of laser skin resurfacing. Used in the continuous mode, the CO2 laser can cut and coagulate simultaneously. Used in the pulsed mode, the CO2 laser is a powerful tool for epidermal ablation in many different contexts both therapeutic and cosmetic. Both the CO2

Karen Riggs; Matthew Keller; Tatyana R. Humphreys

2007-01-01

26

Enamel fusion using a carbon dioxide laser: A technique for sealing pits and fissures  

Microsoft Academic Search

The well-established enhanced resistance of lased enamel to demineralization is the basis for clinical application of the carbon dioxide laser to caries prevention. This in vitro study examined the effect of focused infrared laser radiation on sound enamel and early pit and fissure caries. Low power levels (2-5 W) induced localized melting and resolidification of enamel with little surface destruction.

L. J. Walsh; S. J. Perham

1991-01-01

27

Airborne Validation of Laser Remote Measurements of Atmospheric Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Future space missions to globally map atmospheric carbon dioxide (CO2) at all latitudes during the day and night, such as the ASCENDS (Active Sensing of CO2 Emissions over Night, Day, and Seasons) mission, will require high-precision laser measurements of CO2 columns across the troposphere from low Earth orbit. This paper discusses the development and measurement validation of a unique, multi-frequency, single-beam, laser absorption spectrometer (LAS) that operates at 1.57 ?m, which has been developed for a future space-based mission to determine the global distribution of regional-scale CO2 sources and sinks. A prototype of this space-based LAS system was developed by ITT, and it has been flight tested in eight airborne campaigns conducted over the last five years in Oklahoma, Michigan, New Hampshire, and Virginia under a wide range of atmospheric conditions. This paper focuses on the results obtained during the last two years of flight testing where the remote LAS measurements of CO2 were evaluated against high-quality airborne in situ CO2 measurements made on spirals near the center of the LAS flight tracks. Flight tests over various land and water regions of Virginia in October 2007 showed the high correlation (R2 = 0.995) of the LAS-measured CO2 optical depths (ODs) with altitude, and a high correlation (R2 = 0.996) between the remote and in situ-derived (modeled) CO2 ODs. The average difference between measured and modeled ODs was less than 0.33% or the equivalent of about 1.25 ppmv of CO2. The LAS measurement precision for a 10-s (1 km) average over land was found to be better than 0.7 ppmv and over water was better than 1.4 ppmv. During the flight tests in September-October 2008, improvements in the in situ sampling strategy were implemented, and the average difference between the measured and modeled CO2 ODs was found to be 0.11% or 0.42 ppmv. A comprehensive multiple-aircraft flight test program was conducted over Oklahoma and Virginia in July-August 2009, and this resulted in an average difference between the remote and in situ CO2 ODs for all six flights at all altitudes of 0.10% or 0.40 ppmv with a standard deviation of the results of 0.64% or 2.5 ppmv. LAS instrument improvements also led to a 10-s CO2 measurement precision over land of better than 0.2 ppmv and over water of better than 0.3 ppmv. These high-precision, high-accuracy active remote CO2 measurements represent a major step towards the realization of the needed capability for space-based laser measurements of the global distribution of CO2. Details of the LAS flight tests and comparisons of the observed and modeled CO2 measurements are discussed in this paper.

Browell, Edward V.; Dobler, Jeremy; Kooi, Susan A.; Choi, Yonghoon; Harrison, F. Wallace; Moore, Berrien, III; Zaccheo, T. Scott

2010-05-01

28

Carbon dioxide  

NSDL National Science Digital Library

Bubbles are an indicator of a chemical reaction. An indicator is an object, material, or organism that tells you if a specific substance is present. In the sugar test, carbon dioxide gas release is an indicator that yeast is using sugar to grow. The more gas produced, the more sugar a specific substance contains.

Arie Melamed-Katz (None;)

2007-06-19

29

The NASA high-power carbon dioxide laser - A versatile tool for laser applications  

NASA Technical Reports Server (NTRS)

The NASA Lewis Research Center has designed and fabricated a closed-cycle, continuous wave (CW), carbon dioxide (CO2) high-power laser to support research for the identification and evaluation of possible high-power laser applications. The device is designed to generate up to 70 kW of laser power in annular-shape beams from 1 to 9 cm in diameter. Electric discharge, either self-sustained or electron-beam-sustained, is used for excitation. This laser facility can be used in two ways. First, it provides a versatile tool on which research can be performed to advance the state-of-the-art technology of high-power CO2 lasers in such areas as electric excitation, laser chemistry, and quality of output beams, all of which are important whether the laser application is government or industry oriented. Second, the facility provides a well-defined, continuous wave beam for various application experiments, such as propulsion, power conversion, and materials processing.

Lancashire, R. B.; Alger, D. L.; Manista, E. J.; Slaby, J. G.; Dunning, J. W.; Stubbs, R. M.

1977-01-01

30

Rhinophyma: Carbon dioxide laser with computerized scanner is still an outstanding treatment.  

PubMed

The cosmetic deformity produced by rhinophyma is characterized by nodular hypertrophy of the nasal skin. A retrospective review and analysis of nine consecutive patients with moderate and major rhinophyma treated with scanned carbon dioxide laser was performed. A particular method of continuous scanner use is described. This report demonstrates excellent cosmetic results and no major postoperative complications or recurrence of the condition after 1 year of follow up for seven patients. Two more patients had been followed up for 1 month at the time this paper was written. Scanned carbon dioxide laser is safe and highly effective treatment for rhinophyma. PMID:19916975

Lim, Shueh-Wei; Lim, Shueh-Wen; Bekhor, Phillip

2009-11-01

31

Wound healing in porcine skin following low-output carbon dioxide laser irradiation of the incision  

SciTech Connect

Wound healing of scalpel incisions to the depth of adipose tissue closed with conventional methods was compared with closure by low-output carbon dioxide laser irradiation. In 3 Pitman-Moore minipigs wound healing was evaluated at intervals from 1 to 90 days by the following methods: clinical variables of wound healing; formation of the basement membrane components bullous pemphigoid antigen, laminin, and fibronectin; and histological evaluation of the regeneration of the epidermis, neovascularization, and elastin and collagen formation. There was no significant difference in healing between wounds closed by the various conventional methods and by the low-output carbon dioxide laser.

Robinson, J.K.; Garden, J.M.; Taute, P.M.; Leibovich, S.J.; Lautenschlager, E.P.; Hartz, R.S.

1987-06-01

32

Long pulse, high energy, narrow bandwidth carbon dioxide laser for doppler wind LIDAR applications.  

National Technical Information Service (NTIS)

This paper describes the development of a carbon dioxide laser source with high energy (approx. 10 J/pulse), long pulses (approx. 2 microseconds), narrow bandwidth (approx. 200 kHz), and with a suitable discharge device (Lumonics 602) and cavity configura...

R. Barbini, P. L. Belli, G. Bitelli, F. D'Amato, M. Giorgi

1990-01-01

33

Laser Measurement of the Nitrogen to Carbon Dioxide Vibrational Energy Transfer Time  

Microsoft Academic Search

An experiment is described in which two cavities are installed on a gasdynamic laser. From the power at the downstream cavity, an evaluation of the cross section for vibrational transfer between nitrogen and carbon dioxide can be made. The result is in agreement with other measurements.

J. Wilson

1971-01-01

34

[Familial benign chronic pemphigus (Hailey-Hailey disease): successful treatment with carbon dioxide laser].  

PubMed

Hailey-Hailey disease is a rare, autosomal dominantly inherited genodermatosis, which manifests with recurrent intraepidermal blistering and erythematous hyperkeratotic patches in intertriginous areas. Conventional therapeutic approaches include topical and systemic steroids, antibiotic agents, as well as oral retinoids. Alternative treatments include surgical interventions such as excision, dermabrasion and laser ablation. A 56-year-old woman presented with 15-year history of severe therapy-resistant Hailey-Hailey disease. We performed laser ablation with carbon dioxide laser under general anesthesia. Six weeks after treatment complete remission within ablated areas was achieved. Six-month follow-up showed no relapse. In our opinion carbon dioxide laser ablation represents an effective and safe therapeutic option for Hailey-Hailey disease. PMID:21424889

Kukova, G; Homey, B; Bruch-Gerharz, D; Diedrichson, E

2011-04-01

35

Papillomavirus in the vapor of carbon dioxide laser-treated verrucae  

Microsoft Academic Search

Vapor produced by the carbon dioxide laser during the vaporization of papillomavirus-infected verrucae was analyzed for viral DNA content. Two models were used for evaluation: an in vitro cutaneous bovine fibropapilloma and an in vivo human verruca model. Four bovine fibropapillomas were exposed to various laser parameters with power densities of 38,200 to 130 W\\/cm2 and energy fluences of 3820

J. M. Garden; M K OBanion; L S Shelnitz; K S Pinski; A D Bakus; M E Reichmann; J P Sundberg

1988-01-01

36

Frequency Stabilization of a Ho:Tm:YLF Laser to Absorption Lines of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

A single-frequency Ho:Tm:YLF laser, operating at an eye-safe wavelength of 2 m, has been developed with tuning characteristics optimized for spectroscopy of absorption features. The laser frequency was stabilized to three different absorption lines of carbon dioxide by a wavelength modulation technique. Long-term frequency drift has been eliminated from the laser, and shorter-term jitter has been reduced to within 13.5 MHz of the absorption line center. This stabilized laser is an ideal injection seed source for a differential absorption lidar system for measurement of atmospheric gases.

Koch, Grady J.; Dharamsi, Amin N.; Fitzgerald, Colleen M.; McCarthy, John C.

2000-07-01

37

First Airborne Laser Remote Measurements of Atmospheric Carbon Dioxide for Future Active Sensing of Carbon Dioxide from Space  

NASA Astrophysics Data System (ADS)

Future space missions to globally map atmospheric carbon dioxide (CO2) at all latitudes during the day and night, such as the ASCENDS (Active Sensing of CO2 Emissions over Night, Day, and Seasons) mission, will require high-precision laser measurements of CO2 columns across the troposphere from low Earth orbit. This paper discusses the development and flight demonstration of a unique, multi-frequency, single-beam, laser absorption spectrometer (LAS) that operates at 1.57 ?m, which has been developed for a future space-based mission to determine the global distribution of regional-scale CO2 sources and sinks. A prototype of this space-based LAS system was developed by ITT, and it has been successfully flight tested in six airborne campaigns conducted in different geographic regions over the last four years. Flight tests were conducted over Oklahoma, Michigan, New Hampshire, and Virginia under a wide range of atmospheric conditions. Remote LAS measurements were compared to high-quality in situ measurements obtained from instrumentation on the same aircraft on spirals at the center of the LAS ground tracks. LAS flights were conducted over a wide range of land and water reflectances and in the presence of scattered clouds. The LAS flight tests resulted in the first demonstration of high-precision, high-accuracy, remote laser measurements of CO2 made from an airborne platform. The LAS CO2 column measurements were found to have a precision of better than 2 ppm for a 100-m horizontal average over land and a 1-km average over water. Absolute comparisons of CO2 remote and in situ measurements showed agreement to better than 0.75 percent (

Browell, E. V.; Dobbs, M. E.; Dobler, J.; Kooi, S. A.; Choi, Y.; Harrison, F. W.; Moore, B., III; Zaccheo, T. S.

2009-04-01

38

Effect of a new carbon dioxide laser and fluoride on sound and demineralized enamel  

Microsoft Academic Search

The present study aimed to test the hypothesis that irradiation of dental enamel by a TEA carbon dioxide laser together with fluoride, can effectively inhibit caries-like progression in sound and demineralized enamel. Blocks of human sound and demineralized dental enamel were divided into 11 treatment groups. Eighty enamel blocks were partially demineralized in a 50 percent HAP\\/0.1 M lactic acid\\/carbopol

Marines N. dos Santos; John D. Featherstone; Daniel Fried

2001-01-01

39

Effect of a new carbon dioxide laser and fluoride on occlusal caries progression in dental enamel  

Microsoft Academic Search

The purpose of this study was to investigate the effect of a new TEA carbon dioxide (CO2) laser (.9.6 micrometers , 5-8 microsecond(s) pulse duration) combined with fluoride (F), on the inhibition of caries-like progression in occlusal surfaces in sound and demineralized enamel. Of 120 occlusal tooth surfaces (10 per group), 90 were partially demineralized in a 50% HAP\\/0.1 M

Marines Nobre dos Santos; Daniel Fried; Marcia L. Rapozo-Hilo; John D. Featherstone

2002-01-01

40

Effect of carbon dioxide laser treatment on lesion progression in an intraoral model  

Microsoft Academic Search

Previous studies have shown that pretreatment of dental enamel by specific carbon dioxide laser conditions inhibited subsequent progression of caries-like lesions in vitro. The aim of the present study was to use an intra-oral model to determine whether similar inhibition is observed in the human mouth. A cross over study with 23 subjects and three regimens was used. Pre-formed varies-like

John D. Featherstone; Daniel Fried; Stuart A. Gansky; George K. Stookey; Ann J. Dunipace

2001-01-01

41

Design of catalytic monoliths for closed-cycle carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

A computer program was written that allows the design of catalytic monoliths for closed-cycle carbon dioxide lasers. Using design parameters obtained from workers at NASA Langley Research Center and from the literature, several specific monoliths were designed and the results were communicated to the research group working on this project at Langley. Two oral presentations were made at NASA-sponsored workshops - at Langley in January 1988 and in Gainesville, Florida in May 1988.

Herz, Richard K.

1988-01-01

42

Experimental investigations of driven Alfven wave resonances in a Tokamak plasma using carbon dioxide laser interferometry  

NASA Astrophysics Data System (ADS)

The first direct observation of the internal structure of driven globed Alfven eigenmodes in a Tokamak plasma is presented. A carbon dioxide laser scattering/interferometer has been designed, built, and installed on the PRETEXT Tokamak. The resonance conditions required for, and the spatial wave field structure of, driven plasma eigenmodes at frequencies below the ion cyclotron frequency in a confined, high temperature, Tokamak plasma are investigated.

Evans, T. E.

1984-09-01

43

Selective removal of dental composite using a rapidly scanned carbon dioxide laser  

NASA Astrophysics Data System (ADS)

Dental restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study a carbon dioxide laser operating at high laser pulse repetition rates integrated with a galvanometer based scanner was used to selectively remove composite from tooth surfaces. A diode array spectrometer was used to measure the plume emission after each laser pulse and determine if the ablated material was tooth mineral or composite. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove the composites rapidly from both surfaces with minimal damage to the underlying sound enamel.

Chan, Kenneth H.; Fried, Daniel

2011-02-01

44

Carbon dioxide laser effects on caries-like lesions of dental enamel  

NASA Astrophysics Data System (ADS)

Previous studies by the authors have shown that carbon dioxide (CO2) laser light has marked effects on dental hard tissues and that these effects are wavelength-dependent. The aim of the present study was to determine whether treatment by CO2 laser of caries-like lesions in human enamel would inhibit subsequent lesion progression. Nine groups of 10 teeth each with preformed caries-like lesions were treated with/without CO2 laser (9.32 micrometers , 15 mJ or 25 mJ per pulse) by a pulsed laser (100-200 nsec) for either 200 or 400 pulses. Preformed lesions were then treated with acidulated phosphate fluoride for 5 minutes with control groups with no fluoride treatment. Teeth were subjected to a subsequent pH cycling challenge to determine the protection against lesion progression. Low energy laser treatment coupled with fluoride treatment entirely inhibited subsequent lesion progression in this model system.

Featherstone, John D. B.; Zhang, S. H.; Shariati, M.; McCormack, Sandra M.

1991-05-01

45

Endotracheal tube fires during carbon dioxide laser surgery on the larynx--a case report.  

PubMed

Endotracheal tube (ETT) fire is a catastrophic disaster that may occur during laser surgery of the upper airway. Several means are available for protection of polyvinyl chloride (PVC) tube from fire, but they are not perfect in prevention of fires caused by laser beam. The PVC tube is hazardous for carbon dioxide (CO2) laser surgery if it is not well wrapped with metallized foil tape. We report a case that a PVC ETT wrapped with aluminum foil ignited during CO2 laser surgery of the larynx. In this report, we emphasize the shaft of the PVC tube must be completely wrapped with aluminum foil to prevent exposure of any surface if it is used in CO2 laser surgery of the upper aero digestive tract. PMID:11407297

Kuo, C H; Tan, P H; Chen, J J; Peng, C H; Lee, C C; Chung, H C; Tseng, C K

2001-03-01

46

Helium retards endotracheal tube fires from carbon dioxide lasers.  

PubMed

Polyvinyl chloride (PVC) endotracheal tube segments were exposed to a 5.0-W CO2 laser beam in the presence of different fractions of oxygen and either helium or nitrogen. Time from onset of exposure until ignition was recorded, and mean time to ignition (MTI) was calculated after 10 exposures with the same gas mixture. A second series was done with 40% oxygen in either nitrogen or helium and a laser intensity of 7.5, 10.0, or 12.5 W; a third with 40% oxygen, 60% helium, and 2% halothane and a 10.0-W laser beam; and a fourth with 40% oxygen and 60% helium and a 10.0-W laser beam directed at the radioopaque barium sulfate stripe on the tube. With 5.0-W and 20% oxygen in either nitrogen or helium, segments did not ignite. With concentrations of oxygen greater than 20% in nitrogen, segments ignited sooner than with comparable concentrations in helium: MTIHe = 55.6 s and MTIN2 = 27.6 s in 40% oxygen (P less than 0.05). Sixty per cent helium remained protective at laser intensities up to 10.0 W (MTIHe = 42.6 s vs. MTIN2 = 14.3 s) (P less than 0.05). However, at 12.5 W, MTIHe = 11.5 s and MTIN2 = 11.3 s. Two per cent halothane in 40% oxygen and 60% helium reduced MTIHe to 25.3 s compared with 42.3 s without halothane. With the laser directed at the barium stripe, MTIHe was 7.2 s and MTIN2 1.1 s.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3919615

Pashayan, A G; Gravenstein, J S

1985-03-01

47

Carbon dioxide laser backscatter signatures from laboratory-generated dust  

NASA Astrophysics Data System (ADS)

A dual CO2 laser system was used to measure aerosol backscatter spectral signatures from dust minerals (kaolin, illite, montmorillonite, colemanite, and limestone) as well as from a soil sample from Dugway Proving Ground, UT. Complex refractive indices measured from bulk samples of the materials, and particle size distributions measured with a cascade impactor, were used to compute theoretical backscatter spectra using Mie theory. The measured signatures agreed well with calculated signatures for most minerals and the soil sample. The experiment demonstrated the feasibility of detecting the compositional elements of dust using a CO2 laser-based system.

Walter, D. P.; Cooper, D. E.; van der Laan, J. E.; Murray, E. R.

1986-08-01

48

High-pressure carbon dioxide electrically excited preionization lasers  

Microsoft Academic Search

A review is given of the results of theoretical and experimental investigations of electrically excited preionization gas lasers in which the pressure in the working mixture may reach tens of atmospheres. The method of preionization by external agency is considered and it is reported that, under optimal conditions, practically 100% of the electrical pump energy can be converted into the

N. G. Basov; M Belenov; V. A. Danilychev; A. F. Suchkov

1975-01-01

49

Hollow Dielectric Waveguides for Carbon Dioxide Laser Power Delivery  

Microsoft Academic Search

The present work is an investigation of the optical and mechanical properties of waveguides for the delivery of CO_2 laser radiation with particular emphasis being placed on hollow waveguides. The attenuation, near field output intensity distribution, polarization maintaining ability, and power threshold of several types of hollow waveguides were measured. Theoretical approximations of the attenuation in hollow waveguides are compared

Christopher Carter Gregory

1992-01-01

50

Optically pumped carbon dioxide laser mixtures. [using solar radiation  

NASA Technical Reports Server (NTRS)

This work explores the concept of blackbody radiation pumping of CO2 gas as a step toward utilization of solar radiation as a pumping source for laser action. To demonstrate this concept, an experiment was performed in which laser gas mixtures were exposed to 1500 K thermal radiation for brief periods of time. A gain of 2.8 x 10 to the -3rd reciprocal centimeters has been measured at 10.6 microns in a CO2-He gas mixture of 1 Torr pressure. A simple analytical model is used to describe the rate of change of energy of the vibrational modes of CO2 and to predict the gain. Agreement between the prediction and experiment is good.

Yesil, O.; Christiansen, W. H.

1979-01-01

51

Characteristics of a distributed feedback carbon dioxide laser  

NASA Astrophysics Data System (ADS)

Using a plane wave analysis and perturbation theory, the characteristics of a hollow-core distributed feedback CO2 laser are derived. Expressions for two dimensional fields supported in a rectangular hollow-core dielectric waveguide are developed. Expressions for TE and TM leaky mode loss are also derived. Coupling coefficients for backward scattering modes coupling to the forward incident mode are derived. A double-grating slab waveguide is analyzed where both dielectric interfaces contain identical sinusoidal perturbations. Expressions for waveguide reflectivity are derived in terms of relative phase or position of the two gratings. Construction of a distributed feedback CO2 laser is reported. A method of external discharge pumping to create an active medium in a 76 microns waveguide is discussed.

Miles, R. O.

1978-12-01

52

Carbon dioxide laser monitor for NH in flue gas  

Microsoft Academic Search

An instrument was developed for the detection of NH in flue gas, exploiting a fortuitous spectral overlap between the ..nu..aQ(6,6) absorption line of NH and the R(18) emission line of the isotopic ¹³C¹⁶O laser. The system was developed for use with De-NO\\/sub x\\/ processes, which convert harmful nitric oxides generated in utility and industrial furnaces into harmless nitrogen and water

A. Smith; T. R. Todd; B. N. Perry

1983-01-01

53

Dissociation phenomena in electron-beam sustained carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

A number of applications are emerging requiring efficient, long pulse, long-life sealed CO2 lasers. Examples include the proposed NASA and ESA wind lidars. Electron-beam sustained discharge devices are strong contenders. Unlike self-sustained discharges, e-beam sustenance readily provides efficient performance from large volume discharges and offers pulse lengths well in excess of the microsecond or so generally associated with self-sustained devices. In the case of the e-beam sustained laser, since the plasma is externally maintained and operated at electric field strengths less than that associated with the glow to arc transition, the discharges can be run even in the presence of strongly attacking species such as O2. Build up of large levels of attacking contaminants is nevertheless undesirable as their presence reduces the current drawn by the plasma and thus the pumping rate to the upper laser level. The impedance rise leads to a mismatch of the pulse forming network with a consequent loss of control over energy deposition, operating E/N, and gain. Clearly CO2 dissociation rates, the influence of dissociation products on the discharge and gain, and tolerance of the discharge to these products need to be determined. This information can then be used to assess co-oxidation catalyst requirements for sealed operation.

Harris, Michael R.; Willetts, David V.

1990-01-01

54

Carbon dioxide sequestration monitoring and verification via laser based detection system in the 2 mum band  

NASA Astrophysics Data System (ADS)

Carbon Dioxide (CO2) is a known contributor to the green house gas effect. Emissions of CO2 are rising as the global demand for inexpensive energy is placated through the consumption and combustion of fossil fuels. Carbon capture and sequestration (CCS) may provide a method to prevent CO2 from being exhausted to the atmosphere. The carbon may be captured after fossil fuel combustion in a power plant and then stored in a long term facility such as a deep geologic feature. The ability to verify the integrity of carbon storage at a location is key to the success of all CCS projects. A laser-based instrument has been built and tested at Montana State University (MSU) to measure CO2 concentrations above a carbon storage location. The CO2 Detection by Differential Absorption (CODDA) Instrument uses a temperature-tunable distributed feedback (DFB) laser diode that is capable of accessing a spectral region, 2.0027 to 2.0042 mum, that contains three CO2 absorption lines and a water vapor absorption line. This instrument laser is aimed over an open-air, two-way path of about 100 m, allowing measurements of CO2 concentrations to be made directly above a carbon dioxide release test site. The performance of the instrument for carbon sequestration site monitoring is studied using a newly developed CO2 controlled release facility. The field and CO2 releases are managed by the Zero Emissions Research Technology (ZERT) group at MSU. Two test injections were carried out through vertical wells simulating seepage up well paths. Three test injections were done as CO2 escaped up through a slotted horizontal pipe simulating seepage up through geologic fault zones. The results from these 5 separate controlled release experiments over the course of three summers show that the CODDA Instrument is clearly capable of verifying the integrity of full-scale CO2 storage operations.

Humphries, Seth David

55

Selective Removal of Demineralization Using Near Infrared Cross Polarization Reflectance and a Carbon Dioxide Laser  

PubMed Central

Lasers can ablate/remove tissue in a non-contact mode of operation and a pulsed laser beam does not interfere with the ability to image the tooth surface, therefore lasers are ideally suited for integration with imaging devices for image-guided ablation. Laser energy can be rapidly and efficiently delivered to tooth surfaces using a digitally controlled laser beam scanning system for precise and selective laser ablation with minimal loss of healthy tissues. Under the appropriate irradiation conditions such laser energy can induce beneficial chemical and morphological changes in the walls of the drilled cavity that can increase resistance to further dental decay and produce surfaces with enhanced adhesive properties to restorative materials. Previous studies have shown that images acquired using near-IR transillumination, optical coherence tomography and fluorescence can be used to guide the laser for selective removal of demineralized enamel. Recent studies have shown that NIR reflectance measurements at 1470-nm can be used to obtain images of enamel demineralization with very high contrast. The purpose of this study was to demonstrate that image guided ablation of occlusal lesions can be successfully carried out using a NIR reflectance imaging system coupled with a carbon dioxide laser operating at 9.3-?m with high pulse repetition rates.

Chan, Kenneth H.; Fried, Daniel

2012-01-01

56

Monolith catalysts for closed-cycle carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

The general subject area of the project involved the development of solid catalysts that have high activity at low temperature for the oxidation of gases such as CO. The original application considered was CO oxidation in closed-cycle CO2 lasers. The scope of the project was subsequently extended to include oxidation of gases in addition to CO and applications such as air purification and exhaust gas emission control. The primary objective of the final phase grant was to develop design criteria for the formulation of new low-temperature oxidation catalysts utilizing Monte Carlo simulations of reaction over NASA-developed catalysts.

Herz, Richard K.

1994-01-01

57

Adhesion studies on dental enamel surfaces irradiated by a rapidly scanned carbon dioxide laser  

PubMed Central

In this study, we investigated the influence of different laser scanning patterns on the adhesive strength of laser irradiated enamel surfaces both with and without post ablation acid etching. Previous studies of dental enamel surfaces ablated by a rapidly scanned carbon dioxide laser indicated that the highly uniform smooth surfaces produced by the scanned laser beam yielded low bond strength and acid etching was required in order to attain a high bond strength. However, since the enamel surface after ablation by CO2 lasers is more resistant to acid dissolution it is desirable to avoid acid etching before bonding. The overlap between adjacent laser spots was varied to modify the effective surface roughness. In addition, small retention holes were drilled at higher laser intensity with varying spacing to increase the adhesive strength without acid etching. Varying the degree of overlap between adjacent laser spots did not significantly influence the bond strength with post ablation acid etching. The bond strength was significantly higher without acid etching with retention holes spaced 250-m apart.

Chang, Kwang K.; Staninec, Michal; Chan, Kenneth H.; Fried, Daniel

2011-01-01

58

Effect of extraluminal oxygen on carbon dioxide laser ignition of endotracheal tubes.  

PubMed

Ignition times of endotracheal tubes used in laser surgery have been determined in room air with oxygen flowing through the tube. Using uncuffed endotracheal tubes in children, we measured the oxygen level around the endotracheal tube at the vocal cords and found that it closely approximates the inspired oxygen concentration. We then tested Rusch red rubber and polyvinyl chloride endotracheal tubes while varying the external oxygen concentration. Little difference in ignition time was found for the polyvinyl chloride tube. The red rubber tube ignited significantly faster as the ambient oxygen levels were increased to as little as 30%. Our tests indicate that uncuffed red rubber tubes are not safer than polyvinyl chloride tubes when used with the carbon dioxide laser. All endotracheal tubes used with the laser should be tested for ignition at various extraluminal oxygen concentrations. PMID:1627293

Arnold, J E; Allphin, A L

1992-07-01

59

Hollow dielectric waveguides for carbon dioxide laser power delivery  

SciTech Connect

Present work is an investigation of the optical and mechanical properties of waveguides for the delivery of CO{sub 2} laser radiation with particular emphasis being placed on hollow waveguides. Attenuation, near field output intensity distribution, polarization maintaining ability, and power threshold of several types of hollow waveguides were measured. Theoretical approximations of the attenuation in hollow waveguides are compared with numerical solutions. The use of these waveguides in neurosurgical applications was investigated. The limits of the validity of an approximation of the characteristic equation were investigated by comparing them to a numerical solution of the equation. Approximation of the attenuation of the HE{sub 11} mode was found to be accurate for low index hollow waveguides. The optical properties of five types of round hollow waveguide were measured. The lowest attenuations of PbF{sub 2} coated aluminum and AgI coated silver waveguides were 0.6 and 0.3 dB/m respectively when straight. These waveguides were highly multi-mode and unable to preserve the polarization of the light propagating within them. The lowest attenuations of Ge coated silver and hollow sapphire waveguides were about 1 and 0.6 dB/m respectively for a 1 mm bore size. The output intensity distributions of these waveguides were close to single mode and they were capable of preserving the polarization of the propagating light. The measured losses of the sapphire are more than twice the predicted losses. The excess attenuation of the sapphire waveguides correlates exactly with losses expected from the measured roughness of the inside surface of the sapphire proving surface quality is the limiting factor in present waveguide transmission. The high power capabilities of the sapphire waveguides were found to be in excess of 1500 W. The power limit of the sapphire was determined by flaws in the material and a thermal expansion mismatch between the sapphire and the positioning mount.

Gregory, C.C.

1992-12-31

60

Monolith catalysts for closed-cycle carbon dioxide lasers  

NASA Technical Reports Server (NTRS)

The objective was to explore ways of making a monolithic form of catalyst for CO2 lasers. The approach chosen was to pelletize the catalyst material, Au/MnO2 powder, and epoxy the pellets to stainless steel sheets as structural supports. The CO oxidation reaction over Au/MnO2 powder was found to be first overall, and the reaction rate constant at room temperature was 4.4 +/- 0.3 cc/(g x sec). The activation energy was 5.7 kcal/mol. The BET surface area of the pellets was found to vary from 125 to 140 sq m/g between different batches of catalyst. Pellets epoxied to stainless steel strips showed no sign of fracture or dusting when subjected to thermal tests. Pellets can be dropped onto hard surfaces with chipping of edges but no breakage of the pellets. Mechanical strength tests performed on the pellets showed that the crush strength is roughly one-fourth of the pelletizing force. The apparent activity and activation energy over the pellets were found to be less than over the powdered form of the catalyst. The lower apparent activity and activation energy of the pellets are due to the fact that the internal surface area of a pellet is not exposed to the reactant concentration present in the flowing gas as a result of intrapellet diffusion resistance. Effectiveness factors varied from 0.44, for pellets having thickness of 2 mm and attached with epoxy to a stainless steel strip. The epoxy and the stainless steel strip were found to simply block off one of the circular faces of the pellets. The epoxy did not penetrate the pellets and block the active sites. The values of the effective diffusivities were estimated to be between 2.3 x 10(exp -3) and 4.9 x 10(exp -3) sq cm/s. With measurements performed on one powder sample and one pellet configuration, reasonable accurate predictions can be made of conversions that would be obtained with other pellet thickness and configurations.

Herz, Richard K.; Badlani, Ajay

1991-01-01

61

[Benign familial chronic pemphigus (Hailey-Hailey disease). Treatment with carbon dioxide laser].  

PubMed

Benign familial chronic pemphigus (Hailey-Hailey disease) is an autosomal dominant blistering disease caused by mutations in the ATP2C1 gene encoding a calcium-ATPase which is crucial for intercellular epidermal adhesion. We present a 37-year-old woman with erosions and crusts in both axillary areas. Based on clinical and histological findings, she was diagnosed with benign familial chronic pemphigus. The lesions healed after ablative carbon dioxide laser therapy; no relapse occurred within a follow-up of two years. PMID:20390242

Pissoat, L; Hller Obrigkeit, D

2010-05-01

62

Treatment of nodular facial angiofibromas in tuberous sclerosis, using ultrapulse carbon dioxide laser.  

PubMed

Tuberous sclerosis (TS) is a genodermatosis characterized by facial angiofibromas (FAs). These tumours cause aesthetic disfigurement and obstruction of vision, and haemorrhage when traumatized, which can lead to emotional distress and relationship difficulties. We report the case of a 35-year-old patient with extensive TS-associated FAs that were treated with an ultrapulse carbon dioxide laser (UPCDL). UPCDL laser seems to be a easy, useful and convenient tool for the treatment of nodular FAs, which provides good aesthetic results, and a positive response from patients, who report high levels of satisfaction with the results. Minimal recurrence of the tumours occurred during long-term follow-up, and these were successfully treated with UPCDL. It is not yet possible to correct the genetic alterations underlying TS, but UPCDL treatment is a convenient tool to improve the facial appearance of patients with severe FAs. PMID:24890518

Biondo, G; Greco, S; Mavilia, L; Mercuri, S R

2014-08-01

63

Mitigation of surface damage growth by hydrofluoric acid etching combined with carbon dioxide laser treatment  

NASA Astrophysics Data System (ADS)

Damage sites as large as 600 ?m in fused silica surface were successfully mitigated with a new protocol by hydrofluoric acid (HF) etching combined with carbon dioxide laser treatment. The damage sites were first etched in 40% HF solution to blunt the fractures, and then the etched damage sites were smoothed with a CO2 laser. It has been found that the etching rate of damaged material in the lateral direction is larger than in the longitudinal direction; thus, an optimized etching time was chosen to etch the damage sites based on the etching ratio. Three types of damage test methods were used to confirm the mitigation efficiency of the protocol. The results indicate that the damage resistance capability of mitigated sites can recover to the level of pristine substrate.

Jiang, Yong; Yuan, Xiaodong; He, Shaobo; Zheng, Wanguo; Wang, Haijun; L, Haibing; Ren, Wei; Luo, Chengsi; Liu, Chunming; Xiang, Xia; Zu, Xiaotao

2012-08-01

64

Histologic evaluation of the width of soft tissue necrosis adjacent to carbon dioxide laser incisions  

SciTech Connect

This study evaluated the width of tissue necrosis lateral to carbon dioxide laser incisions on human intraoral excisional biopsy specimens. Measurements were made on specimens including epithelium, muscle, dense and loose connective tissue, and salivary gland. Results showed a mean width of tissue necrosis of 86 microns in epithelium, 85 microns in muscle, 51 microns in loose connective tissue, 96 microns in dense connective tissue, and 41 microns in salivary gland. The range of thermal necrosis in different tissue types is probably based on the water content within each type. A cellular partially homogenized zone of reversible thermal damage up to 500 microns in width was visible adjacent to the zone of thermal necrosis. The relatively narrow width of tissue necrosis with this technique may account for the claimed superior properties of laser-induced wounds compared with those created by electrosurgery.

Pogrel, M.A.; McCracken, K.J.; Daniels, T.E. (Univ. of California, San Francisco (USA))

1990-11-01

65

Carbon dioxide concentrator  

NASA Technical Reports Server (NTRS)

Passed exhaled air through electrochemical cell containing alkali metal carbonate aqueous solution, and utilizes platinized electrodes causing reaction of oxygen at cathode with water in electrolyte, producing hydroxyl ions which react with carbon dioxide to form carbonate ions.

Williams, C. F.; Huebscher, R. G.

1972-01-01

66

Effect of carbon dioxide laser treatment on lesion progression in an intraoral model  

NASA Astrophysics Data System (ADS)

Previous studies have shown that pretreatment of dental enamel by specific carbon dioxide laser conditions inhibited subsequent progression of caries-like lesions in vitro. The aim of the present study was to use an intra-oral model to determine whether similar inhibition is observed in the human mouth. A cross over study with 23 subjects and three regimens was used. Pre-formed varies-like lesions were made in extracted human enamel and exposed intra-orally in partial dentures in each subject to A) placebo dentifrice and no laser treatment, B) placebo dentifrice following laser pretreatment, or C) sodium fluoride dentifrice and no laser treatment during each of three study periods. Samples were assessed by micro radiography to compare the mineral loss before and after each treatment and drive a net change in mineral value. Overall P was not significantly different form L but both P and L were different from F. For those subjects who demineralized in P, L and F were significantly better than P, with L showing an 84 percent inhibition of further demineralization, but no enhancement of demineralization.

Featherstone, John D.; Fried, Daniel; Gansky, Stuart A.; Stookey, George K.; Dunipace, Ann J.

2001-04-01

67

Effect of a new carbon dioxide laser and fluoride on occlusal caries progression in dental enamel  

NASA Astrophysics Data System (ADS)

The purpose of this study was to investigate the effect of a new TEA carbon dioxide (CO2) laser (.9.6 micrometers , 5-8 microsecond(s) pulse duration) combined with fluoride (F), on the inhibition of caries-like progression in occlusal surfaces in sound and demineralized enamel. Of 120 occlusal tooth surfaces (10 per group), 90 were partially demineralized in a 50% HAP/0.1 M Lactic acid/carbopol solution (pH 5.0). Samples were treated with/without the laser (2.0 j/cm2 or 3.0 J/cm2) and/or F (as APF). Caries-like progression was tested by 5 days of pH cycling. Results were assessed by cross-sectional quantitative microradiography. The percent inhibition of caries progression with laser and/or F ranged from 87-170%. This new TEA CO2 laser produced significant protective effect against lesion progression, and in combination with fluoride treatment lesion reversal occurred.

Nobre dos Santos, Marines; Fried, Daniel; Rapozo-Hilo, Marcia L.; Featherstone, John D.

2002-06-01

68

Effect of a new carbon dioxide laser and fluoride on sound and demineralized enamel  

NASA Astrophysics Data System (ADS)

The present study aimed to test the hypothesis that irradiation of dental enamel by a TEA carbon dioxide laser together with fluoride, can effectively inhibit caries-like progression in sound and demineralized enamel. Blocks of human sound and demineralized dental enamel were divided into 11 treatment groups. Eighty enamel blocks were partially demineralized in a 50 percent HAP/0.1 M lactic acid/carbopol solution. Samples were treated with/without laser and/or F according to the above groups. The blocks were then submitted to 5 days of pH cycling. Microradiography was performed on 100 micrometers thin sections to determine the relative mineral loss as (Delta) Z and the percentage of caries inhibition for the laser and F treated groups. Mean (Delta) Z values for groups I-X were, respectively: 1043; 683; 614; 2294; 1803; 1708; 1547; 1791; 1656;; and 1385. The percent caries inhibition for groups II, III, V-X was respectively: 35, 41; 49; 62; 42; 53 and 76 percent. The combination of this new TEA CO2 laser and F treatment produced a significant protective effect against lesion progression.

dos Santos, Marines N.; Featherstone, John D.; Fried, Daniel

2001-04-01

69

Scanner-assisted carbon dioxide laser surgery: A retrospective follow-up study of patients with hidradenitis suppurativa  

Microsoft Academic Search

Background: The chronic fistulating lesions of hidradenitis suppurativa spread by contiguous growth, and all affected tissue needs to be surgically removed. Objective: The aim of our study was to evaluate a surgical method for treatment of Hurley stage II hidradenitis suppurativa (HS), the carbon dioxide laser rapid-beam optomechanical scanner system in continuous mode. Methods: Thirty-four patients were evaluated after treatment;

Jan Lapins; Karin Sartorius; Lennart Emtestam

2002-01-01

70

Infectious papillomavirus in the vapor of warts treated with carbon dioxide laser or electrocoagulation: Detection and protection  

Microsoft Academic Search

Papillomavirus DNA has been reported recently in the vapor (smoke plume) derived from warts treated with carbon dioxide laser; this raises concerns for operator safety. We therefore have studied a group of human and bovine warts to define further the potential risk of wart therapy and to test whether a surgical mask could reduce exposure. Half of each wart was

W. S. Sawchuk; P. J. Weber; D. R. Lowy; L. M. Dzubow

1989-01-01

71

The carbon dioxide cycle  

USGS Publications Warehouse

The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

James, P. B.; Hansen, G. B.; Titus, T. N.

2005-01-01

72

Temperature VS Carbon Dioxide  

NSDL National Science Digital Library

In this activity, students examine the relationship between carbon dioxide levels and global temperature change by studying a graph of these two variables. They will discover that by using data from ice cores, scientists can determine temperature and carbon dioxide levels in the air as far back as a hundred thousand years in the past. The students try to predict which variable is the independent one and then make a graph of temperature change and carbon dioxide levels. After making their graph, students describe the relationship between temperature and carbon dioxide levels in the atmosphere to determine if their predictions were correct.

73

Dynamics of pulsed laser ablation in high-density carbon dioxide including supercritical fluid state  

NASA Astrophysics Data System (ADS)

To gain a better understanding of pulsed laser ablation (PLA) processes in high-density fluids, including gases, liquids, and supercritical fluids (SCFs), we have investigated the PLA dynamics in high-density carbon dioxide (CO2) using a time-resolved shadowgraph (SG) observation method. The SG images revealed that the PLA dynamics can be categorized into two domains that are separated by the gas-liquid coexistence curve and the Widom line, which forms a border between the gaslike and liquidlike domains of an SCF. Furthermore, a cavitation bubble observed in liquid CO2 near the critical point exhibited a particular characteristic: the formation of an inner bubble and an outer shell structure. The results indicate that the thermophysical properties of the reaction field generated by PLA can be dynamically tuned by controlling the solvent temperature and pressure, particularly near the critical point.

Urabe, Keiichiro; Kato, Toru; Stauss, Sven; Himeno, Shohei; Kato, Satoshi; Muneoka, Hitoshi; Baba, Motoyoshi; Suemoto, Tohru; Terashima, Kazuo

2013-10-01

74

Combined carbon dioxide laser and bipolar electrocoagulation: another option to treat rhinophyma.  

PubMed

Rhinophyma is a progressive and disfiguring disorder of the nose characterized by hyperplasia of the sebaceous glands and dermal tissue, representing the end-stage of rosacea. Four male patients affected by a moderate-severe rhinophyma were treated using a combined therapy with carbon dioxide laser and bipolar electrocoagulation. All patients achieved marked cosmetic results with minimal scarring. Various surgical approaches have been described to treat this condition but as yet there is no agreement in the literature on the ideal treatment. This combined method provides a bloodless operative field which allows the sculpting of the hypertrophic areas, leading to a good cosmetic outcome and a pain-free postoperative recovery. PMID:19365784

Cravo, Mariana; Miguel Canelas, Maria; Carlos Cardoso, Jos; Vieira, Ricardo; Figueiredo, Amrico

2009-01-01

75

Evaluation of carbon dioxide laser irradiation associated with calcium hydroxide in the treatment of dentinal hypersensitivity. A preliminary study  

Microsoft Academic Search

Attempts have been made to treat dentinal hypersensitivity by sealing exposed dentinal tubules, and the carbon dioxide (CO2) laser has been shown to have a sealing effect on dentinal surfaces. The purpose of this study was to analyze the morphological\\u000a ultra-structure and temperature change after CO2 laser irradiation of dentin. Fourteen human third molars were selected and cleaned. An area

Ana Cristina Cury Camargo Romano; Ana Cecilia Corra Aranha; Bruno Lopes da Silveira; Snia Lcia Baldochi; Carlos de Paula Eduardo

2011-01-01

76

Capturing Carbon Dioxide  

NSDL National Science Digital Library

In this activity, learners investigate carbon sequestration by creating a carbonated beverage out of apple juice and dry ice. This experiment illustrates how carbon dioxide can be stored in a substance. Learners compare and contrast the results to determine if liquid carbonation is an effective method for carbon sequestration. Safety note: this activity involves dry ice; please follow recommended guidelines.

Saltz, Austen

2010-01-01

77

Carbon Dioxide Emission Estimates  

NSDL National Science Digital Library

The Carbon Dioxide Information Analysis Center of the Oak Ridge National Laboratory provides this new data on carbon dioxide emissions from fossil fuel burning, hydraulic cement production, and gas flaring in 1995. Data for one degree grid cells can be downloaded from the site in addition to code for analysis of the data.

78

Carbon Dioxide Fountain  

ERIC Educational Resources Information Center

This article presents the development of a carbon dioxide fountain. The advantages of the carbon dioxide fountain are that it is odorless and uses consumer chemicals. This experiment also is a nice visual experiment that allows students to see evidence of a gaseous reagent being consumed when a pressure sensor is available. (Contains 3 figures.)

Kang, Seong-Joo; Ryu, Eun-Hee

2007-01-01

79

Carbon Dioxide and Climate.  

ERIC Educational Resources Information Center

The amount of carbon dioxide in the atmosphere is increasing at a rate that could cause significant warming of the Earth's climate in the not too distant future. Oceanographers are studying the role of the ocean as a source of carbon dioxide and as a sink for the gas. (Author/BB)

Brewer, Peter G.

1978-01-01

80

In situ high P-T Raman spectroscopy and laser heating of carbon dioxide  

NASA Astrophysics Data System (ADS)

In situ high P-T Raman spectra of solid CO2 up to 67 GPa and 1660 K have been measured, using a micro-optical spectroscopy system coupled with a Nd:YLF laser heating system in diamond anvil cells. A metallic foil was employed to efficiently absorb the incoming Nd:YLF laser and heat the sample. The average sample temperature was accurately determined by detailed balance from the anti-Stokes/Stokes ratio, and was compared to the temperature of the absorber determined by fitting the thermal radiation spectrum to the Planck radiation law. The transformation temperature threshold and the transformation dynamics from the molecular phases III and II to the polymeric phase V, previously investigated only by means of temperature quench experiments, was determined at different pressures. The P-T range of the transformation, between 640 and 1100 K in the 33-65 GPa pressure interval, was assessed to be a kinetic barrier rather than a phase boundary. These findings lead to a new interpretation of the high P-T phase diagram of carbon dioxide. Furthermore, our approach opens a new way to perform quantitative in situ Raman measurements under extremely high pressures and temperatures, providing unique information about phase relations and structural and thermodynamic properties of materials under these conditions.

Santoro, Mario; Lin, Jung-Fu; Mao, Ho-Kwang; Hemley, Russell J.

2004-08-01

81

In situ high P-T Raman spectroscopy and laser heating of carbon dioxide.  

PubMed

In situ high P-T Raman spectra of solid CO(2) up to 67 GPa and 1,660 K have been measured, using a micro-optical spectroscopy system coupled with a Nd:YLF laser heating system in diamond anvil cells. A metallic foil was employed to efficiently absorb the incoming Nd:YLF laser and heat the sample. The average sample temperature was accurately determined by detailed balance from the anti-Stokes/Stokes ratio, and was compared to the temperature of the absorber determined by fitting the thermal radiation spectrum to the Planck radiation law. The transformation temperature threshold and the transformation dynamics from the molecular phases III and II to the polymeric phase V, previously investigated only by means of temperature quench experiments, was determined at different pressures. The P-T range of the transformation, between 640 and 1,100 K in the 33-65 GPa pressure interval, was assessed to be a kinetic barrier rather than a phase boundary. These findings lead to a new interpretation of the high P-T phase diagram of carbon dioxide. Furthermore, our approach opens a new way to perform quantitative in situ Raman measurements under extremely high pressures and temperatures, providing unique information about phase relations and structural and thermodynamic properties of materials under these conditions. PMID:15281882

Santoro, Mario; Lin, Jung-fu; Mao, Ho-kwang; Hemley, Russell J

2004-08-01

82

Digital calcification in systemic sclerosis: effective treatment with good tissue preservation using the carbon dioxide laser.  

PubMed

Tissue calcification of the fingers associated with limited systemic sclerosis is a common problem and is the source of considerable morbidity as it may be extremely tender and cause considerable functional disability. The current treatment of digital calcification is unsatisfactory. We evaluated the use of the carbon dioxide (CO2) laser in the management of this condition in six patients with the limited form of systemic sclerosis. A total of 21 areas of symptomatic digital calcification of the fingers were treated. Complete resolution of symptoms occurred in 12, moderate response with partial improvement was seen in five, little improvement was observed in two, and recurrence of calcinosis was found in two. The patient's average healing time was 6 weeks (range 4-10). The median duration of follow-up was 20 months (range 12-40). Postoperative infection was seen in two patients, and resolved completely in both with the use of topical and oral antibiotics. We found the CO2 laser a simple and effective treatment for most of the symptomatic lesions of digital calcification, and it may obviate the need for deforming surgery in many cases. PMID:8881679

Bottomley, W W; Goodfield, M J; Sheehan-Dare, R A

1996-08-01

83

Laser Based Instruments Using Differential Absorption Detection for Above and Below Ground Monitoring of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Carbon capture and sequestration in geologic formations provides a method to remove carbon dioxide (CO2) from entering the Earth's atmosphere. An important issue for the successful storage of CO2 is the ability to monitor geologic sequestration sites for leakage to verify site integrity. A field site for testing the performance of CO2 detection instruments and techniques has been developed by the Zero Emissions Research Technology (ZERT) group at Montana State University. A field experiment was conducted at the ZERT field site beginning July 9th, 2008 and ending August 7th, 2008 to test the performance of several CO2 detection instruments. The field site allows a controlled flow rate of CO2 to be released underground through a 100 m long horizontal pipe placed below the water table. A flow rate of 0.3 tons CO2/day was used for the entirety of this experiment. This paper describes the results from two laser based instruments that use differential absorption techniques to determine CO2 concentrations in real time both above and below the ground surface. Both instruments use a continuous wave (cw) temperature tunable distributed feedback (DFB) laser capable of tuning across several CO2 and water vapor absorption features between at 2003 nm and 2006 nm. The first instrument uses the DFB laser to measure path integrated atmospheric concentrations of CO2. The second instrument uses the temperature tunable DFB laser to monitor underground CO2 concentrations using a buried photonic bandgap optical fiber. The above ground instrument operated nearly continuously during the CO2 release experiment and an increase in atmospheric CO2 concentration above the release pipe of approximately 2.5 times higher than the background was observed. The underground instrument also operated continuously during the experiment and saw an increase in underground CO2 concentration of approximately 15 times higher than the background. These results from the 2008 ZERT field experiment demonstrate the potential for these instruments to be used for CO2 monitoring of sequestration sites.

Humphries, S. D.; Barr, J. L.; Repasky, K. S.; Carlsten, J. L.; Spangler, L. H.; Dobeck, L. M.

2008-12-01

84

Carbon Dioxide Monitoring.  

National Technical Information Service (NTIS)

The collection of luminescent microorganisms are maintained under cultivation to provide suitable biosensors for the testing program for carbon dioxide. The basic bioluminescent agar medium is currently being used for growth of the cultures. Tests of lumi...

P. S. Biernacki J. J. Kalvinskas

1973-01-01

85

Carbon dioxide (reduction).  

National Technical Information Service (NTIS)

The twin problems of global warming, caused by an increase in atmospheric carbon dioxide (CO2) concentrations, and limited fossil fuel resources have stimulated research in the utilization of CO2. These problems would be partially alleviated by the develo...

A. Fujita

2000-01-01

86

Progress on High-Energy 2-micron Solid State Laser for NASA Space-Based Wind and Carbon Dioxide Measurements  

NASA Technical Reports Server (NTRS)

Sustained research efforts at NASA Langley Research Center during last fifteen years have resulted in significant advancement of a 2-micron diode-pumped, solid-state laser transmitter for wind and carbon dioxide measurements from ground, air and space-borne platforms. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar system for measuring atmospheric CO2 concentration profiles. Researchers at NASA Langley Research Center have developed a compact, flight capable, high energy, injection seeded, 2-micron laser transmitter for ground and airborne wind and carbon dioxide measurements. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser transmitter was integrated into a mobile trailer based coherent Doppler wind and CO2 DIAL system and was deployed during field measurement campaigns. This paper will give an overview of 2-micron solid-state laser technology development and discuss results from recent ground-based field measurements.

Singh, Upendra N.

2011-01-01

87

Infectious papillomavirus in the vapor of warts treated with carbon dioxide laser or electrocoagulation: Detection and protection  

SciTech Connect

Papillomavirus DNA has been reported recently in the vapor (smoke plume) derived from warts treated with carbon dioxide laser; this raises concerns for operator safety. We therefore have studied a group of human and bovine warts to define further the potential risk of wart therapy and to test whether a surgical mask could reduce exposure. Half of each wart was treated with carbon dioxide laser and the other half with electrocoagulation. The vapor produced by each form of therapy was collected with a dry filter vacuum apparatus and analyzed for the presence of papillomavirus. Vapor from human plantar warts was analyzed for the presence of human papillomavirus DNA, because there is no infectivity assay for human papillomavirus. Of plantar warts treated, five of eight laser-derived vapors and four of seven electrocoagulation-derived vapors were positive for human papillomavirus DNA. Greater amounts of papillomavirus DNA were usually recovered in the laser vapor than in the electrocoagulation vapor from the same wart. Bioassay readily detected infectious bovine papillomavirus in the vapor from bovine warts treated with either modality; more virus was present in laser-derived material. A surgical mask was found capable of removing virtually all laser- or electrocoagulation-derived virus, strongly suggesting that such masks can protect operators from potential inhalation exposure to papillomavirus.

Sawchuk, W.S.; Weber, P.J.; Lowy, D.R.; Dzubow, L.M.

1989-07-01

88

Differential Absorption Measurements of Carbon Dioxide for Carbon Sequestration Site Monitoring Using a Temperature Tunable Diode Laser  

NASA Astrophysics Data System (ADS)

Carbon capture and sequestration in geologic formations provides a method to remove carbon dioxide (CO2) from entering the Earth's atmosphere. An important issue for the successful storage of CO2 is the ability to monitor geologic sequestration sites for leakage to verify site integrity. A differential absorption measurement instrument based on a continuous wave (cw) temperature tunable distributed feedback (DFB) laser has been developed for measuring atmospheric concentrations of CO2. The tunable DFB laser is capable of tuning across two CO2 absorption features at 2003.50 nm and 2004.02 nm. The measured normalized transmission through the atmosphere is then related to the atmospheric concentration of CO2 through the line strength and normalized line width associated with each absorption feature. A description of this instrument will be presented including the instrument design, operation, and performance characteristics. A field site for testing the performance of CO2 detection instruments and techniques has been developed by the Zero Emissions Research Technology (ZERT) group at Montana State University. The field site allows a controlled flow rate of CO2 to be released underground through a 100 m long horizontal pipe placed below the water table. Two release experiments were performed this past summer with flow rates of 0.1 and 0.3 tons CO2/day. The first release experiment lasted ten days while the second release lasted seven days. Measurements taken with the differential absorption instrument over the horizontal well during these release experiments showed an increase of greater than 300 parts per million (ppm) over the background CO2 concentration. These results indicate the capabilities of the above ground differential absorption instrument for carbon sequestration site monitoring.

Humphries, S. D.; Nehrir, A. R.; Repasky, K. S.; Carlsten, J. L.; Spangler, L. H.; Dobeck, L. M.; Shaw, J. A.

2007-12-01

89

Carbon dioxide sensor  

DOEpatents

The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)

2011-11-15

90

Carbon Dioxide Removal  

NSDL National Science Digital Library

In this experiment using sprigs of Elodea, learners will observe a natural process that removes carbon dioxide (CO2) from Earth's atmosphere. This process is a part of the carbon cycle and results in temperature suitable for life. Note: this experiment requires that learners make observations an hour or the next day after they set up the materials.

History, American M.

2008-01-01

91

Comparison of the effect of the carbon dioxide laser and the bipolar coagulator on the cat brain  

SciTech Connect

The carbon dioxide laser has recently received clinical acceptance in neurosurgical practice. There are, however, few studies reported in the neurosurgical literature, either clinical or experimental, concerning its safety or efficacy on a physiological level by comparison to a more conventional tool. This study is not a description of a surgical technique, but is rather a basic physiological comparison of two surgical instruments. In this study, 11 cats were pretreated with the protein-bound dye, Evans blue. A corticotomy was performed in one hemisphere with the carbon dioxide laser and in the other with a microbipolar coagulator and a sharp blade. The subsequent extravasation of dye was presumed to be proportional to the amount of blood-brain barrier disruption associated with each lesion. When effective power settings for the two devices were compared, the laser lesions had significantly less extravasation of blue dye. This indicated that there was less damage to the blood-brain barrier surrounding laser corticotomy than surrounding conventional bipolar coagulation and sharp dissection at comparable power settings for each modality.

Cozzens, J.W.; Cerullo, L.J.

1985-04-01

92

Surgical treatment of rhinophyma using carbon dioxide (CO2) laser and pulsed dye laser (PDL).  

PubMed

Rhinophyma is a slowly progressive, benign dermatological disorder of the nose. The most widely accepted theory is that rhinophyma is the end stage of chronic rosacea. The primary reason for its excision is cosmetic deformity. Many treatment modalities have been described, including CO(2) laser. This method provides a very dry surgical field, which allows the sculpting of the hypertrophic areas. Pulsed dye laser (PDL) is a safe and effective treatment, resulting in a significant improvement in erythema, telangiectases, symptoms and quality of life. We report the case of a 63-year-old Caucasian man with a 2-year history of rapid progression rhinophyma. The patient was submitted to five CO(2) laser sessions, followed by three PDL sessions. Favourable re-epithelization of the surfaces treated with CO(2) laser was achieved within a very short period of time. PDL post-treatment purpura lasted a medium of 12 days. After 12 months of follow-up the patient remains without evidence of relapse. To our knowledge, this is the first case described of treatment using a combination of the CO(2) laser and PDL. PMID:20331343

Moreira, Ana; Leite, Ins; Guedes, Rita; Baptista, Armando; Mota, Gioconda

2010-04-01

93

Carbon Dioxide Exercise  

NSDL National Science Digital Library

In this activity, students work in groups, plotting carbon dioxide concentrations over time on overheads and estimating the rate of change over five years. Stacked together, the overheads for the whole class show an increase on carbon dioxide over five years and annual variation driven by photosynthesis. This exercise enables students to practice basic quantitative skills and understand how important sampling intervals can be when studying changes over time. A goal is to see how small sample size may give incomplete picture of data.

Richardson, Randy; Collection, Serc -.

94

Aspects of carbon dioxide utilization  

Microsoft Academic Search

Carbon dioxide reacts with hydrogen, alcohols, acetals, epoxides, amines, carboncarbon unsaturated compounds, etc. in supercritical carbon dioxide or in other solvents in the presence of metal compounds as catalysts. The products of these reactions are formic acid, formic acid esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, polycarbonate (bisphenol-based engineering polymer), aliphatic polycarbonates, etc. Especially,

Iwao Omae

2006-01-01

95

Carbon Dioxide Laser Keratectomy as a Treatment Option for Equine Corneal Stromal Abscessation: A Comparison to Lamellar Keratectomy and Penetrating Keratoplasty  

Microsoft Academic Search

Carbon dioxide (CO2) laser keratectomy was compared to lamellar keratectomy (LK) and penetrating keratoplasty (PK) as a potential treatment option for equine corneal stromal abscessation. The medical records of 35 client owned horses undergoing surgical management of stromal abscessation were reviewed. Among those 17 underwent LK, 3 PK and 15 CO2 laser keratectomy. Healing of the stromal abscess was achieved

Natasha van Zyl; Stephen G. Rayner

2010-01-01

96

Modeling of carbon monoxide oxidation kinetics over NASA carbon dioxide laser catalysts  

NASA Technical Reports Server (NTRS)

The recombination of CO and O2 formed by the dissociation of CO2 in a sealed CO2 laser discharge zone is examined. Conventional base-metal-oxide catalysts and conventional noble-metal catalysts are not effective in recombining the low O2/CO ratio at the low temperatures used by the lasers. The use of Pt/SnO2 as the noble-metal reducible-oxide (NMRO), or other related materials from Group VIIIA and IB and SnO2 interact synergistically to produce a catalytic activity that is substantially higher than either componet separately. The Pt/SnO2 and Pd/SnO2 were reported to have significant reaction rates at temperatures as low as -27 C, conditions under which conventional catalysts are inactive. The gas temperature range of lasers is 0 + or - 40 C. There are three general ways in which the NMRO composite materials can interact synergistically: one component altering the properties of another component; the two components each providing independent catalytic functions in a complex reaction mechanism; and the formation of catalytic sites through the combination of two components at the atomic level. All three of these interactions may be important in low temperature CO oxidation over NMRO catalysts. The effect of the noble metal on the oxide is discussed first, followed by the effect of the oxide on the noble metal, the interaction of the noble metal and oxide to form catalytic sites, and the possible ways in which the CO oxidation reaction is catalyzed by the NMRO materials.

Herz, Richard K.

1989-01-01

97

Carbon dioxide fixation.  

National Technical Information Service (NTIS)

Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO(sub 2) conv...

E. Fujita

2000-01-01

98

Bench Remarks: Carbon Dioxide.  

ERIC Educational Resources Information Center

Discusses the properties of carbon dioxide in its solid "dry ice" stage. Suggests several demonstrations and experiments that use dry ice to illustrate Avogadro's Law, Boyle's Law, Kinetic-Molecular Theory, and the effects of dry ice in basic solution, in limewater, and in acetone. (TW)

Bent, Henry A.

1987-01-01

99

Carbon Dioxide Increases  

NSDL National Science Digital Library

In this problem set, learners will analyze the Keeling Curve showing carbon dioxide concentration in the atmosphere since 1985 to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

100

Carbon dioxide dangers demonstration model  

USGS Publications Warehouse

Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

Venezky, Dina; Wessells, Stephen

2010-01-01

101

The carbon dioxide laser: an alternative surgery technique for the treatment of common cutaneous tumors in dogs  

PubMed Central

Background Tumors of the skin and subcutaneous tissue are the largest group of canine neoplasms. Total excision is still the most effective method for treatment of these skin tumors. For its universal properties the carbon dioxide (CO2) laser appears to be an excellent surgical instrument in veterinary surgery. Laser techniques are alternatives to traditional methods for the surgical management of tumors. The aim of this study was to compare various types of laser techniques in skin oncologic surgery: excision, ablation and mixed technique and to suggest which technique of CO2 laser procedure is the most useful in particular case of tumors in dogs. Findings The study was performed on 38 privately-owned dogs with total number of 40 skin tumors of different type removed by various CO2 laser operation techniques from 20102013. The treatment effect was based on the surgical wound evaluation, the relative time of healing and possible local recurrence of the tumor after 3 months post surgery. Local recurrence was observed in two cases. The study showed that in 30 cases time needed for complete resection of lesions was less than 10 minutes. Time of healing was longer than 12 days in 6 cases (42.8%) with tumor excision and in 14 cases (87.5%) where excision with ablation technique was performed. Conclusions The advantages of the CO2 laser surgery were better hemostasis, precision of working, non-contact dissection, less instruments at the site of operation and minimum traumatization of the surrounding tissues.

2014-01-01

102

Carbon dioxide adsorbent study  

NASA Technical Reports Server (NTRS)

A study was initiated on the feasibility of using the alkali metal carbonate - bi-carbonate solid-gas reaction to remove carbon dioxide from the atmosphere of an EVA life support system. The program successfully demonstrates that carbon dioxide concentrations could be maintained below 0.1 mole per cent using this chemistry. Further a practical method for distributing the carbonates in a coherent sheet form capable of repeated regeneration (50 cycles) at modest temperatures (423 K), without loss in activity was also demonstrated. Sufficiently high reaction rates were shown to be possible with the carbonate - bi-carbonate system such that EVA hardware could be readily designed. Experimental and design data were presented on the basis of which two practical units were designed. In addition to conventional thermally regenerative systems very compact units using ambient temperature cyclic vacuum regeneration may also be feasible. For a one man - 8 hour EVA unit regenerated thermally at the base ship a system volume of 14 liters is estimated.

Onischak, M.; Baker, B. S.

1973-01-01

103

Modeling Carbon Dioxide Levels  

NSDL National Science Digital Library

In this activity students will explore levels of Carbon Dioxide ( C02) in the atmosphere over time. There is concern that levels of C02 are rising; and finding a good mathematical model for CO2 levels is an important part of determining if this is attributable to human technology. Students draw a scatter plot, choose two points to create a linear model for the data, then use the model to make predictions.

2009-01-01

104

Surface and mineral changes of enamel with different remineralizing agents in conjunction with carbon-dioxide laser  

PubMed Central

Aim: The aim of this study was to evaluate the surface/mineral changes on enamel before and after the application of acidulated phosphate fluoride (APF) gel, fluoride enhanced hydroxyapatite gel and propolis in conjunction with carbon-dioxide (CO2) laser. Materials and Methods: Crowns of 40 human maxillary central incisors were collected and were divided into four groups of 10 each: Topical fluoride application only, topical fluoride application followed by CO2 laser irradiation, CO2 laser irradiation followed by topical fluoride application and CO2 laser irradiation before and after topical fluoride application. The 10 crowns in each group was again sectioned into four equal parts of mesio-incisal, disto-incisal, mesio-cervical and disto-cervical sections rendering 40 samples in each group. Each group was again subdivided into four subgroups: Subgroup C - untreated enamel surface (control). Subgroup A - APF gel application, subgroup R - fluoride enhanced hydroxyapatite gel application and subgroup P - propolis application. The surface morphology of the test samples were analyzed by scanning electron microscopy and mineral changes by energy dispersion X-ray spectrophotometer. Results: Total mineral content is maximum in Group 4A (CO2 laser irradiation before and after APF gel application) and calcium/phosphate ratio is highest in Group 4R (CO2 laser irradiation before and after Remin-Pro application). Group 2A (APF gel application followed by CO2 laser irradiation) has the maximum fluoride retention. Conclusion: Laser irradiation of enamel through a topically applied APF gel is effective in the prophylaxis and management of dental caries.

Mohan, Ajit George; Ebenezar, A. V. Rajesh; Ghani, Mohamed Fayas; Martina, Leena; Narayanan, Ashwin; Mony, Bejoy

2014-01-01

105

Efficacy and Safety of 10,600-nm Carbon Dioxide Fractional Laser on Facial Skin with Previous Volume Injections  

PubMed Central

Background: Fractionated carbon dioxide (CO2) lasers are a new treatment modality for skin resurfacing. The cosmetic rejuvenation market abounds with various injectable devices (poly-L-lactic acid, polymethyl-methacrylate, collagens, hyaluronic acids, silicone). The objective of this study is to examine the efficacy and safety of 10,600-nm CO2 fractional laser on facial skin with previous volume injections. Materials and Methods: This is a retrospective study including 14 patients treated with fractional CO2 laser and who have had previous facial volume restoration. The indication for the laser therapy, the age of the patients, previous facial volume restoration, and side effects were all recorded from their medical files. Objective assessments were made through clinical physician global assessment records and improvement scores records. Patients satisfaction rates were also recorded. Results: Review of medical records of the 14 patients show that five patients had polylactic acid injection prior to the laser session. Eight patients had hyaluronic acid injection prior to the laser session. Two patients had fat injection, two had silicone injection and one patient had facial thread lift. Side effects included pain during the laser treatment, post-treatment scaling, post-treatment erythema, hyperpigmentation which spontaneously resolved within a month. Concerning the previous facial volume restoration, no granulomatous reactions were noted, no facial shape deformation and no asymmetry were encountered whatever the facial volume product was. Conclusion: CO2 fractional laser treatments do not seem to affect facial skin which had previous facial volume restoration with polylactic acid for more than 6 years, hyaluronic acid for more than 0.5 year, silicone for more than 6 years, or fat for more than 1.4 year. Prospective larger studies focusing on many other variables (skin phototype, injected device type) are required to achieve better conclusions.

Helou, Josiane; Maatouk, Ismael; Moutran, Roy; Obeid, Grace; Stephan, Farid

2013-01-01

106

Use of the carbon dioxide laser in guided tissue-regeneration wound healing in the beagle dog  

NASA Astrophysics Data System (ADS)

The concept of guided tissue regeneration (GTR) allowing cells from the periodontal ligament and alveolar bone to repopulate the treated root surface has shown the ability to obtain periodontal new attachment. Healing studies have also shown that conventional GTR therapy still does not exclude all the epithelium. This epithelial proliferation apically interferes with the establishment of the new connective tissue attachment to the root surface. The objective of this research study was to examine whether controlled de-epithelialization with the carbon dioxide laser during the healing phase after periodontal surgery, would retard the apical migration of the epithelium and thereby enhance the results obtained through guided tissue regeneration. Eight beagle dogs were used, the experimental side received de-epithelialization with the CO2 laser in conjunction with flap reflection and surgically created buccal osseous defects. Selected defects on each side were treated with ePTFE periodontal membranes. The laser de-epithelialization was repeated every 10 days until removal of the membranes. The control side received the same surgical treatment without laser application. This experimental design allowed histologic study of the new attachment obtained in defects treated with flap debridement with or without laser de-epithelialization and with or without ePTFE membranes. A statistical analysis was performed on the histometric data from 48 teeth in the 8 dogs after 4 months of healing. The results showed significant amounts of new attachment obtained from all four treatment modalities with no statistically significant differences for any one treatment. However, the trend towards enhanced regeneration with the combined treatment of laser and membrane vs. membrane alone or debridement alone was evident. The histologic analysis revealed a significant amount of newly formed `fat cementum' seen only on the laser treated teeth. This feature was the most remarkable finding of the study and warrants further research to understand the origin of this phenomenon.

Rossmann, Jeffrey A.; Parlar, Ates; Abdel-Ghaffar, Khaled A.; El-Khouli, Amr M.; Israel, Michael

1996-04-01

107

Histopathologic and morphometric evaluation of the skin abnormalities induced by erbium:YAG and carbon dioxide lasers in 10 patients.  

PubMed

In the 1960s, carbon dioxide (CO2) laser therapy started to be applied to eliminate wrinkles, actinic scars, and acne because of its capacity of induce intracellular water vaporization. However, recent studies have shown the efficacy of the erbium laser in removing delicate and moderate scars. Furthermore, the postoperative lesions induced by the erbium laser seem to resolve faster and with less erythematous pattern compared with lesions induced by the CO2 laser. The purpose of this study was to determine the immediate pathologic alterations caused by single applications of CO2 and erbium lasers and their association in human skin shreds. Ten white female patients aged 30 to 63 years underwent rhytidectomy, and their respective shreds, which were prepared for excision, were tattooed with the CO2 laser, the erbium laser, or a combination of both in random order and number of applications, before final removal. This project was approved by the local ethical committee. After surgical removal, these tattooed shreds were fixed in 10% buffered formalin and submitted to histopathologic analysis. Morphometric studies demonstrated the normal skin thickness and thickness of the laser-treated area, and their subtraction resulted in the ablation damage values. Residual thermal damage corresponded to the thickness of the affected skin from the most superficial layer of tissue in the laser-treated area down to the deepest dermal area with basophilic degeneration of collagen fibers. Our results showed that two CO2 applications resulted in greater ablation and residual thermal damage when compared with only one CO2 application. The same was true in comparisons of one and two applications of the erbium laser. Both results were statistically significant (p < 0.05). When one isolated erbium and one isolated CO2 application were compared, ablation damage was greater in the former group, although with no statistical significance. One CO2 plus one erbium application compared with one isolated CO2 application showed similar ablation damage but greater residual thermal damage in the latter group (p < 0.05). These observations might contribute to our understanding of the lesions caused in the human skin by erbium and CO2 lasers and eventually help determine the ideal laser combination for the appropriate surgical treatment. PMID:11604648

de Noronha, L; Chin, E W; Menini, C M; Knopfholz, J; Rampazzo, J C; Graf, R

2001-10-01

108

Carbon Dioxide Capture and Disposal  

NASA Astrophysics Data System (ADS)

Unless carbon dioxide from fossil fuel combustion is captured and disposed of safely and permanently, the concerns over climate change will eventually lead to the demise of fossil fuels. Because of their importance in today's energy market the phasing out of fossil fuels would likely precipitate a major energy crisis. Mineral sequestration and extraction of carbon dioxide from the air are two advanced technologies for carbon sequestration that aim at maintaining access to the vast fossil energy resources for centuries to come. While it is straightforward to dispose of carbon dioxide in limited amounts and for a limited time, permanent disposal of trillions of tons of carbon poses serious challenges. The formation of solid mineral carbonates from readily available minerals would provide safe and permanent storage. Capture of carbon dioxide from air makes it possible to sequester carbon dioxide emissions from sources other than power plants. This is important considering that even the relatively minor reductions suggested by the Kyoto Accord would have required the US to eliminate carbon dioxide emissions comparable to those of the entire 1990 coal fired power plant fleet. Capture of carbon dioxide from the air, would make it possible to close the carbon cycle in the transportation sector without phasing out liquid hydrocarbon fuels. It eliminates the need for long distance transport of carbon dioxide and allows the continued use of the existing energy infrastructure. Mineral sequestration at remote sites combined with on site carbon dioxide capture from air, would allow for long term stabilization of atmospheric carbon dioxide levels. I will outline the current state of the technology and point to advances required before these approaches are ready for large-scale implementation.

Lackner, K. S.

2002-05-01

109

Carbon dioxide sequestration by mineral carbonation  

Microsoft Academic Search

The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals

W. J. J. Huijgen; R. N. J. Comans

2007-01-01

110

Carbon dioxide and climate  

SciTech Connect

Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

Not Available

1990-10-01

111

Use of Zernike polynomials and interferometry in the optical design and assembly of large carbon-dioxide laser systems  

SciTech Connect

This paper describes the need for non-raytracing schemes in the optical design and analysis of large carbon-dioxide lasers like the Gigawatt, Gemini, and Helios lasers currently operational at Los Alamos, and the Antares laser fusion system under construction. The scheme currently used at Los Alamos involves characterizing the various optical components with a Zernike polynomial set obtained by the digitization of experimentally produced interferograms of the components. A Fast Fourier Transform code then propagates the complex amplitude and phase of the beam through the whole system and computes the optical parameters of interest. The analysis scheme is illustrated through examples of the Gigawatt, Gemini, and Helios systems. A possible way of using the Zernike polynomials in optical design problems of this type is discussed. Comparisons between the computed values and experimentally obtained results are made and it is concluded that this appears to be a valid approach. As this is a review article, some previously published results are also used where relevant.

Viswanathan, V.K.

1981-01-01

112

Simultaneous Measurements of Leaf and Soil Carbon Dioxide Flux Using a Tunable Diode Laser  

NASA Astrophysics Data System (ADS)

A portable photosynthesis system (Li-6400, Li-Cor, NE) and a through-flow soil chamber were used to continuously measure the gas exchange of leaf and below ground components in pots containing corn, Triticale and a non-planted control. Temperature was kept constant through-out the experiment, and measurements were made at 4 min intervals over a full diurnal light cycle. A tunable diode laser (TGA100A, Campbell Scientific, UT) was used to measure the concentration and stable isotopic composition (?13C and ?18O) of the air entering and exiting both chambers. End-member isotope values were determined by short-term incubation of component parts in Tedlar bags, and the evolved gas was measured with the laser. These data were used to determine the isotopic signature of CO2 derived from root respiration, microbial respiration of plant derived exudates and soil organic matter (SOM) to allow the partitioning of the total flux into component parts. The ?13C of SOM respiration was identical when measured with the soil chamber on the control pots and when using incubated samples from the same pots. However, incubation of the potting mix in the other treatments was more enriched (corn) and more depleted (Triticale) than the control, indicating that end-member determination of the original SOM was confounded by exudates from the plants. Using a mixing model to partition the soil respiration, and the ?13C of SOM from the control pots, corn roots contributed 25% and Triticale 72% of the below-ground respiration. Incubation of soil with the roots removed allowed non-root respiration to be partitioned into contributions from pre-existing SOM and more recent plant derived exudates for corn (23% recent carbon) and Triticale (36% recent carbon).

Hunt, J. E.; Barbour, M. M.

2007-12-01

113

Absorption of Carbon Dioxide on Carbonic Anhydrase Containing Substrates.  

National Technical Information Service (NTIS)

Carbonic anhydrase (CA), an enzyme catalyzing carbon dioxide hydration, was evaluated for its enhancement of carbon dioxide removal when it is present in granular materials with high water content during exposure to carbon dioxide in an aerating stream. A...

J. P. Allen

1968-01-01

114

Sampling Carbon Dioxide  

NSDL National Science Digital Library

In this lab activity, student teams hypothesize which source has a greater becomes CO² concentration: their breath, auto exhaust, or air in the classroom. They test gas samples from each of these sources, plot data, and hypothesize about the respective role engine exhaust and animal respiration play in contemporary climate change. The lab procedures require Bromthymol Blue indicator solution (BTB), household ammonia, vinegar, and balloons. Links to videos supporting the investigations are provided. This activity is supported by a textbook chapter, "How is Carbon Dioxide Measured?," part of the unit, Climate Change, in Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

115

Carbon dioxide: atmospheric overload  

SciTech Connect

The level of carbon dioxide in the atmosphere is increasing and may double within the next century. The result of this phenomenon, climatic alterations, will adversely affect crop production, water supplies, and global temperatures. Sources of CO2 include the combustion of fossil fuels, photosynthesis, and the decay of organic matter in soils. The most serious effect of possible climatic changes could occur along the boundaries of arid and semiarid regions. Shifts is precipitation patterns could accelerate the processes of desertification. An increase of 5..cap alpha..C in the average temperature of the top 1000 m of ocean water would raise sea level by 2 m. CO2 releases to the atmosphere can be reduced by controlling emissions from fossil fuel-fired facilities and by careful harvesting of forest regions. (3 photos, 5 references)

Not Available

1980-04-01

116

Ex vivo investigations of laser auricular cartilage reshaping with carbon dioxide spray cooling in a rabbit model.  

PubMed

Laser cartilage reshaping (LCR) with cryogen spray cooling is a promising modality for producing cartilage shape change while reducing cutaneous thermal injury. However, LCR in thicker tissues, such as auricular cartilage, requires higher laser power, thus increasing cooling requirements. To eliminate the risks of freeze injury characteristic of high cryogen spray pulse rates, a carbon dioxide (CO2) spray, which evaporates rapidly from the skin, has been proposed as the cooling medium. This study aims to identify parameter sets which produce clinically significant reshaping while producing minimal skin thermal injury in LCR with CO2 spray cooling in ex vivo rabbit auricular cartilage. Excised whole rabbit ears were mechanically deformed around a cylindrical jig and irradiated with a 1.45-?m wavelength diode laser (fluence 12-14 J/cm(2) per pulse, four to six pulse cycles per irradiation site, five to six irradiation sites per row for four rows on each sample) with concomitant application of CO2 spray (pulse duration 33-85 ms) to the skin surface. Bend angle measurements were performed before and after irradiation, and the change quantified. Surface temperature distributions were measured during irradiation/cooling. Maximum skin surface temperature ranged between 49.0 to 97.6 C following four heating/cooling cycles. Significant reshaping was achieved with all laser dosimetry values with a 50-70 C difference noted between controls (no cooling) and irradiated ears. Increasing cooling pulse duration yielded progressively improved gross skin protection during irradiation. CO2 spray cooling may potentially serve as an alternative to traditional cryogen spray cooling in LCR and may be the preferred cooling medium for thicker tissues. Future studies evaluating preclinical efficacy in an in vivo rabbit model are in progress. PMID:23307439

Wu, Edward C; Sun, Victor; Manuel, Cyrus T; Protsenko, Dmitriy E; Jia, Wangcun; Nelson, J Stuart; Wong, Brian J F

2013-11-01

117

Use of a carbon dioxide laser for surgical management of cutaneous masses in horses: 65 cases (1993-2004)  

NASA Astrophysics Data System (ADS)

The purpose of this study was to evaluate the outcome of horses treated for cutaneous masses with the carbon dioxide (CO2) laser. The records of 65 horses were examined. Surgery was performed under general anesthesia or standing under sedation and local anesthesia. Excision was performed freehand using a focused beam with power settings ranging from 10 to 32 Watts in a continuous mode. Following en bloc removal of masses the subcutaneous tissue and wound margins were photovaporized using a defocused beam. Follow-up information was obtained via telephone interview with owners or referring veterinarians Cutaneous masses were divided into three groups: sarcoid (29), neoplasia including squamous cell carcinoma (15), melanoma (6), schwanoma (2), fibroma (1), and fibrosarcoma (1), and non-neoplastic masses (11). Mass reoccurrence developed in 8 of 29 (28%) sarcoids and 4 of 14 (29%) squamous cell carcinoma. No reoccurrence was reported for horses diagnosed with melanoma, schwanoma, fibrosarcoma, fibroma, or any of the non-neoplastic masses. Sixty of 63 owners (95%) reported that they were satisfied with the outcome of the procedure. This study demonstrates that the CO2 laser is an effective means of treating cutaneous masses in horses.

Hawkins, Jan F.; McCauley, Charles T.

2005-04-01

118

Fractional scanned carbon dioxide laser induces collagen remodelling in murine dermis  

Microsoft Academic Search

Resurfacing using a fractional CO2 laser shows an important promise in the therapy on photoaged skin. The present study investigated that fractional CO2 laser with a special sequential scanned manner induced the collagen remodelling in murine dermis. The results showed that laser resulted in the improvement of elasticity and histology in the murine dermis, meaning laser efficacy depends on both

X. Jiang; H. M. Ge; J. J. Liu; Q. S. Ren

2011-01-01

119

Low-output carbon dioxide laser for cutaneous wound closure of scalpel incisions: comparative tensile strength studies of the laser to the suture and staple for wound closure  

SciTech Connect

The low-output carbon dioxide (CO/sub 2/) laser was used for cutaneous wound closure of scalpel incisions. Cutaneous scalpel incisions were placed over the dorsum of three minipigs and were then closed by either the laser, sutures, or staples. At multiple time points after wound closure, up to day 90, the tensile strengths of these wounds were comparatively evaluated. All wounds, including those closed with the laser, clinically appeared to heal similarly with no evidence of wound dehiscence or infection. Tensile strength studies revealed similar sigmoid curves for all wound closure modalities with low initial tensile strengths up to days 14 to 21, which afterwards increased rapidly, with a plateau toward day 90. From our study, it appears that the CO/sub 2/ laser, in the low-output mode, can be used for cutaneous wound closure and that similar clinical healing and tensile strength measurements are obtained relative to the conventional cutaneous wound closure modalities of the suture or staple.

Garden, J.M.; Robinson, J.K.; Taute, P.M.; Lautenschlager, E.P.; Leibovich, S.J.; Hartz, R.S.

1986-01-01

120

Fractional scanned carbon dioxide laser induces collagen remodelling in murine dermis  

Microsoft Academic Search

Resurfacing using a fractional CO2 laser shows an important promise in the therapy on photoaged skin. The present study investigated that fractional CO2 laser with a special sequential scanned manner induced the collagen remodelling in murine dermis. The results showed that\\u000a laser resulted in the improvement of elasticity and histology in the murine dermis, meaning laser efficacy depends on both

X. Jiang; H. M. Ge; J. J. Liu; Q. S. Ren

2011-01-01

121

Carbon Dioxide and Ocean Acidification  

NSDL National Science Digital Library

Demonstrates the affect of increased dissolved carbon dioxide on water pH using a cheap, non-toxic acid/base indicator. Students bubble breath through a straw into red cabbage juice and note the color change.

Lewis, Chris

122

NASA Satellite Sees Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will analyze a map of atmospheric carbon dioxide derived from satellite data. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

123

Safe and Effective One-Session Fractional Skin Resurfacing Using a Carbon Dioxide Laser Device in Super-Pulse Mode: A Clinical and Histologic Study  

Microsoft Academic Search

Carbon dioxide (CO2) laser ablative fractional resurfacing produces skin damage, with removal of the epidermis and variable portions of the dermis\\u000a as well as associated residual heating, resulting in new collagen formation and skin tightening. The nonresurfaced epidermis\\u000a helps tissue to heal rapidly, with short-term postoperative erythema. The results for 40 patients (8 men and 32 women) after\\u000a a single

Mario A. Trelles; Michael Shohat; Fernando Urdiales

2011-01-01

124

Carbon Dioxide Laser Saturation Spectroscopy and the Hyperfine Structure of Monosubstituted Ozone 16O 16O 17O and 16O 17O 16O  

NASA Astrophysics Data System (ADS)

Carbon dioxide lasers have been used in an offset-lock configuration to obtain saturation spectra of ozone, monosubstituted with O-17, at a linewidth of a few kHz. Rich hyperfine structures result from the O-17 nucleus, spin 5/2. These are used, together with earlier microwave data, to obtain the corresponding hyperfine parameters. The spectra also illustrate the sensitivity of hyperfine structures to subtle vibration-rotation interactions.

Butcher, R. J.; Saubama, B.; Chardonnet, Ch.

1998-04-01

125

Shock Wave Acceleration of Monoenergetic Protons using a Multi-Terawatt Carbon Dioxide Laser  

NASA Astrophysics Data System (ADS)

Compact and affordable ion accelerators based on laser-produced plasmas have potential applications in many fields of science and medicine. However, the requirement of producing focusable, narrow-energy-spread, energetic beams has proved to be challenging. In this thesis, an experimental demonstration of the generation of monoenergetic ions via collisionless electrostatic shock waves driven in a laser produced plasma is presented. The physical processes behind shock wave formation, propagation, and their potential to produce monoenergetic ion beams is explored using 1D OSIRIS simulations. It is observed that a shock wave can be formed from the interpenetration of two plasmas via the expansion from a density discontinuity or an initial relative drift velocity. These processes can be instigated in the laser driven case where the laser can produce a moving sharp density spike and strong electron heating as it bores a hole through an overdense plasma. Under appropriate conditions, an electrostatic shock is formed that detaches from he laser and propagates in the plasma even after the laser is turned off. This shock can then overtake and reflect ions from the upstream plasma and accelerate them to yield a relatively narrow energy spread. A multi-terawatt CO2 laser system was developed at the UCLA Neptune Laboratory for exploring laser-driven shock wave acceleration of ions. The theory behind CO2 amplification of picosecond pulses where the bandwidth is provided by the pressure of the CO2 gas and the field of the laser pulse itself is developed. These ideas are applied for the production of 3 ps CO2 laser pulses with peak powers of up to 15 TW, currently the most powerful CO2 laser pulses ever produced. These laser pulses were used for laser-driven shock wave acceleration of protons in a hydrogen gas jet where the peak plasma density is in the range of 3--5 ncr, where ncr is the critical plasma density for 10 mum radiation. Interferometry using a picosecond 532 nm laser pulse showed that the plasma has a dynamically formed profile with a sharp (10lambda) rise to overcritical densities and a long exponential fall (30lambda). Protons accelerated from this interaction reach energies of 22 MeV, are contained within a narrow energy spread of 1%, and have geometrical emittances as low as a mm mrad. 2D OSIRIS simulations show that the laser-driven shock overtakes and reflects the protons in the slowly expanding hydrogen plasma resulting in a narrow energy spectrum. Scaling of this mechanism to higher laser powers through simulations predict the production of 200 MeV protons needed for radiotherapy by using current laser technology.

Haberberger, Daniel Joseph

126

Carbon dioxide laser versus stapler-assisted endoscopic Zenker's diverticulotomy: a systematic review and meta-analysis.  

PubMed

To evaluate outcomes following endoscopic management of Zenker's diverticula using a carbon dioxide laser (CO2) or stapler-assisted technique, a systematic review and meta-analysis were conducted. Seven retrospective, uncontrolled case series including 391 procedures met selection criteria. No higher quality studies were identified. Outcomes favoring the stapler technique included a shorter duration of nil per os (NPO) status (2 studies), length of hospitalization (LOH, 2 studies), and fewer postoperative fevers and abnormal chest x-rays (1 study). Outcomes favoring the CO2 technique included greater improvement in postoperative dysphagia and regurgitation scores (2 studies) and a lower revision rate (1 study). Meta-analysis demonstrated increased nondental complications in the CO2 group (odds ratio 3.81; 95% confidence interval, 1.37-10.59; P = .01) but no difference in duration of NPO (P = .06), LOH (P = .07), overall complications (P = .08), dental complications (P = .57), major complications (P = .38), or revision surgery (P = .82). Implications are limited by the quality of studies identified. PMID:24496741

Parker, Noah P; Misono, Stephanie

2014-05-01

127

Fires of endotracheal tubes of three different materials during carbon dioxide laser surgery.  

PubMed

The hazards of fire during CO2 laser surgery of the airway necessitate the use of special endotracheal tubes. We reviewed 227 cases receiving CO2 laser laryngeal surgery over the past 7 years, of whom 3 suffered the complications as a result of endotracheal fire. Tracheal tubes made of different materials were used among them, including silicone T-tube (Montgomery Safe-T-tube), jet ventilation tube and Xomed laser shield endotracheal tube. In addition, we tested in vitro the combustibility of endotracheal tubes of six different materials which included silicone T-tube, jet ventilation tube, Xomed laser shield endotracheal tube, stainless Laser-Flex tracheal tube, polyvinyl chloride (PVC) endotracheal tube and aluminum foil wrapped PVC endotracheal tube by exposing them to continuous operating CO2 laser in room air. The time to initiation of fire and burn through the lumen was 0.3 second for T-tube, 0.5 s for jet ventilation tube, 5 s for Xomed laser shield endotracheal tube, and 0.8 s for PVC endotracheal tube, respectively. The Laser-Flex tracheal tube (stainless) and aluminum foil wrapped PVC endotracheal tube did not catch fire after 30 s of CO2 laser irradiation. The silicone T-tube seemed to be the most dangerous. Jet ventilation tube and Xomed laser shield endotracheal tube have the risk of fire. Aluminum foil wrapped PVC endotracheal tube was reported to catch fire before. Therefore we are of the opinion that the stainless endotracheal tube is the safest tube during CO2 laser surgery. PMID:11989049

Lai, Hui-Chin; Juang, Sin-Ei; Liu, Tsun-Jui; Ho, Wai-Ming

2002-03-01

128

Vaginal intraepithelial neoplasia: treatment by carbon dioxide laser and risk factors for failure  

Microsoft Academic Search

Objective: To evaluate the effectiveness of CO2 laser ablation of vaginal intraepithelial neoplasia (VAIN) and to define prognostic factors. Study Design: Medical records of 24 patients with VAIN II or III, treated by CO2 laser ablation from 1990 to 1998 were reviewed. The grade, location, and focality of the lesions, the age, follow-up period and menopausal status of the patients,

Omer T Yalcin; Thomas J Rutherford; Setsuko K Chambers; Joseph T Chambers; Peter E Schwartz

2003-01-01

129

A simplified quasi-two-dimensional model for gain optimization in carbon dioxide gasdynamic lasers (GDL)  

Microsoft Academic Search

In this paper a simplified quasi-two-dimensional model for small signal gain optimization in gasdynamic laser is introduced. In order to obtain a homogeneous medium with maximum optical gain in the active medium, by nozzle shape formation, the shock occurrence position is controlled and is postponed to some point behind the laser active medium. Then the method of calculus of variation

A. R. Bahrampour; R.-M. Farrahi; M. Radjabalipour

2002-01-01

130

Stalegenskaperna hos en 3 kw Koldioxidlaser (Beam Properties of a 3 kw Carbon Dioxide Laser),  

National Technical Information Service (NTIS)

In a series of experiments, the beam properties of a continuous 3 kW fast axial flow CO2 laser was surveyed. Spectrally, the laser worked steadily in the P20 transition, independent of warming up period or output power. Within the measurement accuracy, th...

S. J. Frolov

1988-01-01

131

Optogalvanic stabilization and offset tuning of a carbon dioxide waveguide laser  

NASA Technical Reports Server (NTRS)

A feedback loop employing the change in discharge impedance with output power is used to stabilize the frequency of a CO2 waveguide laser. The relatively high operating pressure of the laser combined with a zero offset feature in the feedback loop allows continuous tuning of the stabilized frequency over a 300-400 MHz range.

Kavaya, M. J.; Menzies, R. T.; Oppenheim, U. P.

1982-01-01

132

New technique for feline carbon dioxide laser onychectomy by resection of the redundant epidermis of the ungual crest  

NASA Astrophysics Data System (ADS)

A new technique for feline carbon dioxide laser onychectomy can further minimize postoperative pain and complications in any age animal. This procedure is accomplished by resection of the redundant epidermis over the ungual crest. Resection of the redundant epidermis allows complete dissection and removal of the claw from a strictly cranio-dorsal approach, thereby minimizing trauma to the surrounding tissues and post- operative complications. The laser setting is preferred at four to six watts continuous power. The epidermis of the ungual crest is resected in a circumferential manner at its most distal edge. This tissue is pushed proximally over the ungual crest. A second circumferential incision is made 3 mm proximal to the first incision. Deeper subcutaneous fascia is also pushed proximally over the ungual crest. An incision of the extensor tendon is made at its insertion on the ungual crest keeping the redundant epidermis proximal to this incision. The incision through the extensor tendon is continued deeper to the synovium of PII and PIII. Gentle traction in a palmar direction will disarticulate the joint space between PII and PIII. Incisions into the lateral and medial collateral ligaments from a cranio-dorsal origin in palmar direction further disarticulate the joint. Care must be exercised to preserve all epidermal tissue lying immediately adjacent to the collateral ligaments. Continual palmar traction will expose the base of PIII and the insertion of the flexor tendon. A dorsal incision is made into the flexor tendon in a palmar direction. Extreme palmar rotation of PIII will allow the dissection of the subcutaneous tissue of the pad from PIII. The redundant epidermal tissue will now cover the majority of the onychectomy site. No sutures or tissue adhesive are advised.

Young, William P.

2000-05-01

133

Carbon dioxide laser turbinectomy versus submucosal diathermy of hypertrophied turbinates. Histopathological prospective study  

NASA Astrophysics Data System (ADS)

Aim: To assess suspected turbinate mucosal distractive changes of CO2 laser partial turbinectomy as compared to submucosal diathermy technique of hypertrophied inferior turbinates and thus risk of appearance of mucosal atrophic changes. Introduction: CO2 laser turbinotomy or turbinectomy has become an established well documented line of treatment of hypertrophied inferior turbinates not responding to medical treatment. Although there have been several reports discussing the clinical aspects of laser turbinectomy, but exact pathological changes that take place following laser application to the turbinate have not been described completely and clearly. For this reason this study was conducted to confirm these possible histopathological changes and compared with those following submucosal diathermy technique. Patients and methods: Twenty patients with chronic hypertrophied inferior turbinates and presenting mainly with nasal obstruction, ten out of them were subjected to CO2 laser turbinectomy while other half underwent to submucosal diathermy technique. Tiny biopsies were taken immediately after surgery (within one week after surgery ), as well as 4-6 weeks later and processed for further histopathological evaluation. Results: By 100%, the all patients of two groups showed areas of epithelial loss were observed immediately after both techniques. 4-6 weeks after laser application 60% of patients showed normal epithelial areas as compared to second group where 20% of patients who showed normal epithelial picture. Conclusion: CO2 laser turbinectomy can be considered as more preservative technique for nasal mucosa as well as the function of the nose as compared to submucosal diathermy technique.

Mohamed Bofares, Khalid

2010-05-01

134

Combined effects of carbon dioxide laser and fluoride on demineralized primary enamel: an in vitro study.  

PubMed

This in vitro study aimed at evaluating the efficacy of a CO(2) laser (10.6 microm) alone or combined with acidulated phosphate fluoride (APF) on the inhibition of lesion progression in primary enamel. The specimens were treated with/without CO(2) laser and/or APF and submitted to pH cycling. Microhardness analysis was performed and the enamel mineral loss values were obtained. The groups treated with laser and/or APF presented lower mineral loss when compared to the control group (p < 0.05). Laser irradiation alone or combined with APF decreased lesion progression in primary enamel. However, the combined treatment did not show any significant additional effect. PMID:17167263

Tagliaferro, E P S; Rodrigues, L K A; Nobre Dos Santos, M; Soares, L E S; Martin, A A

2007-01-01

135

Mixing of argon-ion and carbon dioxide laser radiation in uniaxial rubidium chlorate crystals  

Microsoft Academic Search

Mixing in uniaxial RbClO3 of visible and infrared photons emitted, respectively, by an argon-ion and CO2 laser has been examined at room temperature under conditions in which the two laser beams propagate collinearly in the single crystal. The intensity dependence of the Stokes (down-converted) and anti-Stokes (up-converted) mixed-phonon signals has been measured as a function of the propagation direction of

D. M. Hwang; S. A. Solin

1974-01-01

136

Combined Effects of Carbon Dioxide Laser and Fluoride on Demineralized Primary Enamel: An in vitro Study  

Microsoft Academic Search

This in vitro study aimed at evaluating the efficacy of a CO2 laser (10.6 ?m) alone or combined with acidulated phosphate fluoride (APF) on the inhibition of lesion progression in primary enamel. The specimens were treated with\\/without CO2 laser and\\/or APF and submitted to pH cycling. Microhardness analysis was performed and the enamel mineral loss values were obtained. The groups

E. P. S. Tagliaferro; L. K. A. Rodrigues; M. Nobre dos Santos; L. E. S. Soares; A. A. Martin

2007-01-01

137

Spectrophone stabilization and offset tuning of a carbon dioxide waveguide laser  

NASA Technical Reports Server (NTRS)

A sensitive spectrophone containing CO2 gas is incorporated into a feedback loop to stabilize the frequency of a CO2 waveguide laser. First or second harmonic detection combined with a zero offset feature and the relatively high operating pressure of the laser allows continuous tuning of the stabilized frequency over a 400 MHz range. Frequency stability of better than + or - 1 MHz is achieved.

Kavaya, M. J.; Menzies, R. T.; Oppenheim, U. P.

1983-01-01

138

a Study of Small Solid-State Switched Tea Carbon Dioxide Lasers  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. This thesis records the results of a theoretical and experimental investigation into the use of all solid -state exciters with small corona preionised TEA CO _2 lasers. To overcome the limitations of existing semiconductor devices energy pulse compression techniques were utilised. High energy efficiency at low repetition rates was provided by the use of unreset ferrite magnetic cores in a magnetic pulse compressor. A high repetition rate laser system was also produced and operated at 1kHz producing 18 W of optical power. In order to further improve energy efficiency a number of different laser exciter topologies were evaluated. The successful operation of a thyristor stack driven laser enabled a comparative study with a conventional hydrogen thyratron drive circuit to be undertaken. It was found that all solid-state exciters could be as energy efficient as conventional drive techniques. The desire to minimise the amount of pulse energy switched by semiconductor elements lead to an examination of photoswitching methods in which the laser head acts as its own switch. Finally, long optical pulse generation was achieved by the use of pulser sustainer techniques which enabled optical pulses over 20 mus long to be produced.

Sylvan, Alan

139

Magnesite disposal of carbon dioxide  

SciTech Connect

In this paper we report our progress on developing a method for carbon dioxide disposal whose purpose it is to maintain coal energy competitive even is environmental and political pressures will require a drastic reduction in carbon dioxide emissions. In contrast to most other methods, our approach is not aiming at a partial solution of the problem, or at buying time for phasing out fossil energy. Instead, its purpose is to obtain a complete and economic solution of the problem, and thus maintain access to the vast fossil energy reservoir. A successful development of this technology would guarantee energy availability for many centuries even if world economic growth the most optimistic estimates that have been put forward. Our approach differs from all others in that we are developing an industrial process which chemically binds the carbon dioxide in an exothermic reaction into a mineral carbonate that is thermodynamically stable and environmentally benign.

Lackner, K.S.; Butt, D.P.; Wendt, C.H.

1997-08-01

140

Sapphire Fibers for ERBIUM:YAG and Hollow Waveguides for Industrial Carbon Dioxide Laser Power Delivery.  

NASA Astrophysics Data System (ADS)

This work is an investigation of specialty fiber optics for laser power delivery. Solid single-crystal sapphire fibers for the delivery of Er:YAG laser energy were grown using the laser-heated pedestal-growth method. Hollow -sapphire and metal--dielectric-coated hollow-glass waveguides were used to deliver CO_2 laser power for industrial laser applications. Single-crystal sapphire fibers have been grown using the laser-heated pedestal-growth method with losses as low as 0.3 dB/m at 2.94 mum. With the incorporation of a computer-controlled feedback system we have grown fibers with less than +/-0.5% diameter variation, or +/-1.5 mu m for a 300-?m fiber. We have been able to decrease the loss in these fibers through a post-growth anneal at 1000^circ C in air; from 5.4 dB/m to 1.5 dB/m at 543 nm and from 0.4 dB/m to 0.3 dB/m at 2.94 mum. These fibers delivered 4.7 W at 10 Hz of Er:YAG laser power. The loss and output beam properties of our single -crystal sapphire fiber was found to be a function of the Er:YAG laser beam quality. Near single-mode output was obtained from our lowest-loss sapphire fibers with a single -mode input beam. The output was always multimode when the input beam was multimode. Sapphire fibers with a high internal scattering loss had a highly multimode output beam regardless of the input beam quality. Hollow-sapphire and metal--dielectric-coated hollow -glass waveguides have been used to deliver CO_2 laser power for industrial laser applications. The transmission, bending loss, and output-beam properties of these waveguides are described. The bore sizes of the hollow-sapphire waveguides were 1070 and 790 mu m, and the hollow-glass waveguide had a bore of 700 mum. The waveguides ranged in length from 1.1 to 1.5 m. The sapphire waveguides were bent to 90^circ, and the hollow -glass waveguides were bent into a full 360^ circ loop. We delivered a maximum of 1.8 kW through the 1070-mum-bore sapphire waveguide and 1.0 kW through the hollow-glass waveguide. All the hollow waveguides incorporated a water jacket to prevent overheating. Theoretical calculations are presented on the coupling efficiency from multimode industrial CO ^2 lasers to hollow waveguides. To assess the maximum laser power safe for continuous use of these hollow waveguides, theoretical calculations on the temperature distribution with water cooling are also presented.

Nubling, Ricky Kenneth

141

Carbon dioxide laser tissue welding: an alternative technique for tubal anastomosis?  

PubMed

Microsurgical tubal anastomosis is the gold standard for treatment of tubal occlusion. The present study was performed to establish the feasibility of tubal anastomosis by welding tissue with a defocused CO2-laser beam during laparotomy and with an endoscope. In an animal experiment, 70 white New Zealand rabbits were randomized in 2 study groups (E1, E2) and 3 control groups (C1, C2, C3) as follows: C1, 10 animals, no operation, as controls for the efficiency of the insemination technique; C2, 5 animals, spontaneous healing after tubal segment resection, to quantify spontaneous recanalization of the tube; C3, 15 animals, microsurgical end-to-end adaption after tubal segment resection; E1, 20 animals, laser welded anastomosis after segment resection via laparotomy; E2, 20 animals, laparoscopic laser welded anastomosis after segment resection. The pregnancy rate in C1 was 80%. None of the animals in C2 but 60% of the rabbits in C3 conceived. After sutureless anastomosis by laser welding 50% of the laparotomized, and 40% of the laparoscopically operated group became pregnant. Morphological examination of the oviducts after relaparotomy showed comparable patency rates of 70% in C3, 70% in E1, and 65% in E2. Whereas no dehiscence of anastomoses was observed in C3, 20% of the welded tubes in E1 and 22.5% in E2 were dehiscent. Tubal anastomosis took approximately three times as long laparoscopically as during laparotomy. Thus, laser welding as a sutureless alternative technique of tubal anastomosis should be viewed critically. A reduction of sutures through laser-assisted anastomosis might, however, be considered. PMID:9612164

Wallwiener, D; Meyer, A; Bastert, G

1997-01-01

142

Infrared image construction with computer-generated reflection holograms. [using carbon dioxide laser  

NASA Technical Reports Server (NTRS)

Computer-generated reflection holograms hold substantial promise as a means of carrying out complex machining, marking, scribing, welding, soldering, heat treating, and similar processing operations simultaneously and without moving the work piece or laser beam. In the study described, a photographically reduced transparency of a 64 x 64 element Lohmann hologram was used to make a mask which, in turn, was used (with conventional photoresist techniques) to produce a holographic reflector. Images from a commercial CO2 laser (150W TEM(00)) and the holographic reflector are illustrated and discussed.

Angus, J. C.; Coffield, F. E.; Edwards, R. V.; Mann, J. A., Jr.; Rugh, R. W.; Gallagher, N. C.

1977-01-01

143

REVIEWS OF TOPICAL PROBLEMS: High-pressure carbon dioxide electrically excited preionization lasers  

Microsoft Academic Search

A review is given of the results of theoretical and experimental investigations of electrically excited preionization gas lasers in which the pressure in the working mixture may reach tens of atmospheres. The method of preionization by external agency is considered and it is reported that, under optimal conditions, practically 100% of the electrical pump energy can be converted into the

N. G. Basov; . M. Belenov; V. A. Danilychev; A. F. Suchkov

1975-01-01

144

Measurement of 9.6-Micron Carbon Dioxide Laser Transition Probability and Optical Broadening Cross Section.  

National Technical Information Service (NTIS)

Measurements of the 9.6- and 10.6-micrometer CO2 laser transition probabilities and optical cross sections have been made by using a tuneable CO2 leaser and room-temperature absorption cell. In order to increase the accuracy of the resulting constants, tw...

C. Kruger E. R. Murray M. Mitchner

1973-01-01

145

Swallowing function after endoscopic resection of supraglottic carcinoma with the carbon dioxide laser  

Microsoft Academic Search

From April 1998 to May 2000, 14 patients with supraglottic cancer underwent transoral laser surgery (T-stage T12: 11 patients,\\u000a T3: 3 patients). In three patients, an epiglottectomy or hemi-epiglottectomy was performed. In 11 patients, further structures\\u000a (false cords, the valleculae and the base of the tongue and\\/or parts of the arytenoid cartilage) had to be resected. Thirteen\\u000a patients had to

Jens Oeken; Uta Hnsch; Susanne Thiel; Friedrich Bootz

2001-01-01

146

Photodynamic Therapy with Ablative Carbon Dioxide Fractional Laser for Treating Bowen Disease  

PubMed Central

Background Topical photodynamic therapy (PDT) has been increasingly used to treat malignant skin tumors including the Bowen disease. However, patients could be displeased with the long incubation time required for conventional PDT. Objective We evaluated the efficacy and safety of PDT with a short incubation time of ablative CO2 fractional laser pretreatment for treating Bowen disease. Methods Ten patients were included. Just before applying the topical photosensitizer, all lesions were treated with ablative CO2 fractional laser, following the application of methyl aminolevulinate and irradiation with red light (Aktilite CL 128). Histological confirmation, rebiopsy, and clinical assessments were performed. Adverse events were also recorded. Results Five of the ten (50%) lesions showed a complete response (CR) within three PDT sessions. After four treatment sessions, all lesions except one penile shaft lesion (90%) achieved clinical and histological CR or clinical CR only. The average number of treatments to CR was 3.701.70. The treatments showed favorable cosmetic outcomes and no serious adverse events. Conclusion The results suggest that pretreatment with an ablative fractional CO2 laser before PDT has similar treatment efficacy and requires a shorter photosensitizer incubation time compared with the conventional PDT method.

Kim, Sue Kyung; Park, Ji-Youn; Song, Hyo Sang; Kim, You-Sun

2013-01-01

147

[Carcinoma in situ of the penis rapidly progressing after carbon dioxide laser treatment].  

PubMed

Laser treatment is considered to be effective in treating carcinoma in situ of the penis. We, however, report a case with carcinoma in situ of the penis which developed invasive carcinoma and inguinal lymphnode metastases only 6 months after the laser treatment. A 74-year-old man with pseudophimosis presented with redness of the glans penis. A physical examination revealed thick erythema, 12 millimeters in diameter, around the external urethral meatus. Histologically, biopsy revealed squamous cell carcinoma in situ. No metastasis was suspected by physical examination and imaging studies. Although the lesion appeared to slightly extend into the urethra, it was primarily treated with the CO2 laser. Six months after the treatment, however, local recurrence was confirmed by the touch smear cytology, resulting in the partial amputation of the penis. The histopathological examination revealed subepithelial and marked lymphatic invasion of the tumor and positive margin in the urethral stump (squamous cell carcinoma in situ). Further, since bilateral superficial inguinal lymphnode swelling appeared, total amputation of the penis with perineal urethrotomy and pelvic/inguinal lymphnode dissection was performed subsequently. The metastases to bilateral inguinal lymphnodes were confirmed histologically. The patient received adjuvant chemotherapy and has been alive and well without evidence of disease 40 months after the initial treatment. PMID:11968805

Tsukamoto, Tetsuro; Yonese, Junji; Kin, Taisei; Samejima, Takeshi; Hasegawa, Yuichi; Fukui, Iwao; Ishikawa, Yuichi

2002-03-01

148

Carbon Dioxide - Our Common "Enemy"  

NASA Technical Reports Server (NTRS)

Health effects of brief and prolonged exposure to carbon dioxide continue to be a concern for those of us who manage this pollutant in closed volumes, such as in spacecraft and submarines. In both examples, considerable resources are required to scrub the atmosphere to levels that are considered totally safe for maintenance of crew health and performance. Defining safe levels is not a simple task because of many confounding factors, including: lack of a robust database on human exposures, suspected significant variations in individual susceptibility, variations in the endpoints used to assess potentially adverse effects, the added effects of stress, and the fluid shifts associated with micro-gravity (astronauts only). In 2007 the National Research Council proposed revised Continuous Exposure Guidelines (CEGLs) and Emergency Exposure Guidelines (EEGLs) to the U.S. Navy. Similarly, in 2008 the NASA Toxicology Group, in cooperation with another subcommittee of the National Research Council, revised Spacecraft Maximum Allowable Concentrations (SMACs). In addition, a 1000-day exposure limit was set for long-duration spaceflights to celestial bodies. Herein we examine the rationale for the levels proposed to the U.S. Navy and compare this rationale with the one used by NASA to set its limits. We include a critical review of previous studies on the effects of exposure to carbon dioxide and attempt to dissect out the challenges associated with setting fully-defensible limits. We also describe recent experiences with management of carbon dioxide aboard the International Space Station with 13 persons aboard. This includes the tandem operations of the Russian Vozduk and the U.S. Carbon Dioxide Removal System. A third removal system is present while the station is docked to the Shuttle spacecraft, so our experience includes the lithium hydroxide system aboard Shuttle for the removal of carbon dioxide. We discuss strategies for highly-efficient, regenerable removal of carbon dioxide that could meet the 1000-day SMAC of 0.5%, which would apply to long-duration voyages to Mars.

James, John T.; Macatangay, Ariel

2009-01-01

149

Carbon Dioxide Absorption Heat Pump  

NASA Technical Reports Server (NTRS)

A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

Jones, Jack A. (Inventor)

2002-01-01

150

Experiment and modeling: Ignition of aluminum particles with a carbon dioxide laser  

NASA Astrophysics Data System (ADS)

Aluminum is a promising ingredient for high energy density compositions used in propulsion systems, explosives, and pyrotechnics. Aluminum powder fuel additives enable one to achieve higher combustion enthalpies and reaction temperatures. Therefore, to develop aluminum based novel and customized high density energetic materials, understanding of ignition and combustion kinetics of aluminum powders is required. In most practical systems, metal ignition and combustion occur in environments with rapidly changing temperatures and gas compositions. The kinetics of exothermic reactions in related energetic materials is commonly characterized by thermal analysis, where the heating rates are very low, on the order of 1--50 K/min. The extrapolation of the identified kinetics to the high heating rates is difficult and requires direct experimental verification. This difficulty led to development of new experimental approaches to directly characterize ignition kinetics for the heating rates in the range of 103--104 K/s. However, the practically interesting heating rates of 106 K/s range have not been achieved. This work is directed at development of an experimental technique and respective heat transfer model for studying ignition of aluminum and other micron-sized metallic particles at heating rates varied around 106 K/s. The experimental setup uses a focused CO2 laser as a heating source and a plate capacitor aerosolizer to feed the aluminum particles into the laser beam. The setup allows using different environment for particle aerosolization. The velocities of particles in the jet are in the range of 0.1 --0 3 m/s. For each selected jet velocity, the laser power is increased until the particles are observed to ignite. The ignition is detected optically using a digital camera and a photomultiplier. The ignition thresholds for spherical aluminum powder were measured at three different particle jet velocities, in air environment. A single particle heat transfer model was developed to describe the experiments. Experiments with different jet velocities in air environment were performed to validate the model. The interaction of the laser beam with particles is particle size dependent and a narrow range of particle sizes (around 3.4 microm) is heated most effectively. Therefore, the heat transfer model needs to be analyzed only for the particles with this specific size, which greatly simplifies the interpretation of experiments. Describing heating of a micron sized metal particle involves the transition regime heat transfer. A modified Fuchs model was used to describe the heat transfer in this study. In addition to dry air environment, the experimental technique was also used with other oxidizing environments, including O2, H2O, CO2 and mixtures thereof. It was observed that particle size capable of maintaining a vapor phase flame is a function of the environment. Arrhenius model kinetics parameters for Al ignition in O2, CO2 and H2O environments were determined.

Mohan, Salil

151

Infrared planar laser-induced fluorescence imaging and applications to imaging of carbon monoxide and carbon dioxide  

Microsoft Academic Search

This dissertation introduces infrared planar laser- induced fluorescence (IR PLIF) techniques for visualization of species that lack convenient electronic transitions and are therefore unsuitable for more traditional electronic PLIF measurements. IR PLIF measurements can generate high signal levels that scale linearly with both laser energy and species concentration, thereby demonstrating advantages over Raman and multiphoton PLIF techniques. IR PLIF is

Brian James Kirby

2001-01-01

152

Hydrocarbon Displacement by Carbon Dioxide Dispersions.  

National Technical Information Service (NTIS)

The US Department of Energy's (DOE) Morgantown Energy Technology Center (METC) is investigating methods to control the mobility of carbon dioxide for use in gas miscible displacements of hydrocarbons that are found in petroleum reservoirs. Carbon dioxide ...

J. R. Duda

1986-01-01

153

Diffraction et Deflection dans le Tellurium pour le Laser Carbon-Dioxide  

NASA Astrophysics Data System (ADS)

Cette these fait suite au travail realise ces dix dernieres annees relatif aux effets acoustooptiques (AO) dans les materiaux, ainsi qu'a une premiere observation indiquant que le tellurium possede une valeur de merite (M) exceptionnellement elevee a la longueur d'onde 10.6 ?m du laser CO_2, pour une certaine configuration de l'onde acoustique et optique. Une analyse plus generale et plus complete de la diffraction et de la deflection a des frequences acoustiques simples et multiples est presentee ainsi que pour la premiere fois, les resultats d'une analyse experimentale et quantitative de la diffraction et de la deflection AO pour les configurations birefringentes et isotropiques qui couvrent l'espace entier du crystal. L'expression de l'efficacite de diffraction est derivee pour les interactions du premier-ordre, pour une condition generale de propagation acoustique et optique. Une expression complete de la valeur de merite est par consequent obtenue. La relation entre les angles de Bragg incidents et diffractes en fonction de la frequence acoustique est egalement obtenue. Ces dernieres relations permettent de calculer les bandes passantes de diffraction et les angles de deflection correspondants, en prenant en consideration l'activite optique lorsque les faisceaux optiques se propagent pres de l'axe OZ. Un programme experimental detaille a ete entrepris afin de mesurer les coefficients inconnus du tenseur photoelastique du tellurium et les caracteristiques de diffraction AO dans des cas typiques particulierement choisis des plans d'interaction et des parametres optiques et acoustiques. Utilisant le comportement acoustique connu du tellurium et le tenseur photoelastique complet, nous avons fait fonctionner pour la premiere fois un programme d'ordinateur, dont le but est de calculer toutes les valeurs de (M) et en particulier celles qui sont les plus elevees, dans tout l'espace du crystal, pour les interactions isotropiques et birefringentes. Les configurations optimuns pour la deflection et la modulation du laser CO_2 ont ete analysees. (Abstract shortened with permission of author.).

Souilhac, Dominique Jacques

154

Ablation of Dental Hard Tissues with a Microsecond Pulsed Carbon Dioxide Laser Operating at 9.3-?m with an Integrated Scanner.  

PubMed

Pulsed carbon dioxide lasers operating at the highly absorbed 9.3 and 9.6-?m wavelengths with pulse durations in the microsecond range are ideally suited for dental hard tissue modification and removal. The purpose of these studies was to demonstrate that a low cost 9.3-?m CO(2) laser system utilizing low-energy laser pulses (1-5 mJ /pulse) delivered at a high repetition rate (400-Hz) is feasible for removing dental hard tissues. The laser beam was focused to a small spot size to achieve ablative fluence and an integrated/programmable optical scanner was used to scan the laser beam over the desired area for tissue removal. Pulse durations of 35, 60 and 75-?s were employed and the enamel and dentin ablation rate and ablation efficiency were measured. Laser irradiated human and bovine samples were assessed for peripheral thermal and mechanical damage using polarized light microscopy. The heat accumulation during rapid scanning ablation with water-cooling at 400-Hz was monitored using micro-thermocouples. The laser was able to ablate both enamel and dentin without excessive peripheral thermal damage or heat accumulation. These preliminary studies suggest that a low-cost RF excited CO(2) laser used in conjunction with an integrated scanner has considerable potential for application to dental hard tissues. PMID:22228978

Assa, Shlomo; Meyer, Steve; Fried, Daniel

2008-01-01

155

Ablation of Dental Hard Tissues with a Microsecond Pulsed Carbon Dioxide Laser Operating at 9.3-?m with an Integrated Scanner  

PubMed Central

Pulsed carbon dioxide lasers operating at the highly absorbed 9.3 and 9.6-?m wavelengths with pulse durations in the microsecond range are ideally suited for dental hard tissue modification and removal. The purpose of these studies was to demonstrate that a low cost 9.3-?m CO2 laser system utilizing low-energy laser pulses (1-5 mJ /pulse) delivered at a high repetition rate (400-Hz) is feasible for removing dental hard tissues. The laser beam was focused to a small spot size to achieve ablative fluence and an integrated/programmable optical scanner was used to scan the laser beam over the desired area for tissue removal. Pulse durations of 35, 60 and 75-?s were employed and the enamel and dentin ablation rate and ablation efficiency were measured. Laser irradiated human and bovine samples were assessed for peripheral thermal and mechanical damage using polarized light microscopy. The heat accumulation during rapid scanning ablation with water-cooling at 400-Hz was monitored using micro-thermocouples. The laser was able to ablate both enamel and dentin without excessive peripheral thermal damage or heat accumulation. These preliminary studies suggest that a low-cost RF excited CO2 laser used in conjunction with an integrated scanner has considerable potential for application to dental hard tissues.

Assa, Shlomo; Meyer, Steve; Fried, Daniel

2011-01-01

156

Process for sequestering carbon dioxide and sulfur dioxide  

DOEpatents

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Maroto-Valer, M. Mercedes (State College, PA); Zhang, Yinzhi (State College, PA); Kuchta, Matthew E. (State College, PA); Andresen, John M. (State College, PA); Fauth, Dan J. (Pittsburgh, PA)

2009-10-20

157

Carbon dioxide transport over complex terrain  

USGS Publications Warehouse

The nocturnal transport of carbon dioxide over complex terrain was investigated. The high carbon dioxide under very stable conditions flows to local low-ground. The regional drainage flow dominates the carbon dioxide transport at the 6 m above the ground and carbon dioxide was transported to the regional low ground. The results show that the local drainage flow was sensitive to turbulent mixing associated with local wind shear.

Sun, J.; Burns, S. P.; Delany, A. C.; Oncley, S. P.; Turnipseed, A.; Stephens, B.; Guenther, A.; Anderson, D. E.; Monson, R.

2004-01-01

158

Carbon dioxide and ammonia detection using 2 ?m diode laser based quartz-enhanced photoacoustic spectroscopy  

NASA Astrophysics Data System (ADS)

Quartz-enhanced photoacoustic spectroscopy was employed for trace gas concentration measurements of CO2 and NH3 using a continuous wave thermoelectrically cooled, distributed feedback diode laser operating at 2 ?m. A normalized noise equivalent absorption coefficient, NNEA(1?)=1.410-8 cm-1W/sqrt{text{Hz}} was obtained for CO2 using the R18 line of the 2?1+?3 band at 4991.26 cm-1. This corresponds to minimum detection limit (1?) of 18 parts per million (ppm) for a 1 s lock-in time constant. The influence of the H2O presence in the sample gas mixture on the CO2 sensor performance was investigated. Ammonia detection was performed using the P P 6(6)S line of the ?3+?4 band at 4986.99 cm-1. A detection limit (1?) of 3 ppm for NH3 concentration with a 1 s lock-in time constant was achieved. This results in a normalized noise equivalent absorption of NNEA(1?)=8.910-9 cm-1W/sqrt{text{Hz}}.

Lewicki, R.; Wysocki, G.; Kosterev, A. A.; Tittel, F. K.

2007-03-01

159

Solid-State 2-Micron Laser Transmitter Advancement for Wind and Carbon Dioxide Measurements From Ground, Airborne, and Space-Based Lidar Systems  

NASA Technical Reports Server (NTRS)

NASA Langley Research Center has been developing 2-micron lidar technologies over a decade for wind measurements, utilizing coherent Doppler wind lidar technique and carbon dioxide measurements, utilizing Differential Absorption Lidar (DIAL) technique. Significant advancements have been made towards developing state-of-the-art technologies towards laser transmitters, detectors, and receiver systems. These efforts have led to the development of solid-state lasers with high pulse energy, tunablility, wavelength-stability, and double-pulsed operation. This paper will present a review of these technological developments along with examples of high resolution wind and high precision CO2 DIAL measurements in the atmosphere. Plans for the development of compact high power lasers for applications in airborne and future space platforms for wind and regional to global scale measurement of atmospheric CO2 will also be discussed.

Singh, Upendra N.; Kavaya, Michael J.; Koch, Grady; Yu, Jirong; Ismail, Syed

2008-01-01

160

Carbon Dioxide - Sources and Sinks  

NSDL National Science Digital Library

In this lab activity, students use a chemical indicator (bromothymol blue) to detect the presence of carbon dioxide in animal and plant respiration and in the burning of fossil fuels and its absence in the products of plant photosynthesis. After completing the five parts of this activity, students compare the colors of the chemical indicator in each part and interpret the results in terms of the qualitative importance of carbon sinks and sources.

Universe, Windows T.

161

RECARBONATION AND LIQUID CARBON DIOXIDE  

Microsoft Academic Search

After water has been lime-softened, it is frequently caustic; pH reduction is usually achieved by adding carbon dioxide to the watera process called recarbonation. Here is a history of recarbonation, with up-to-date information for modern installations.

Paul D. Haney; Carl L. Hamann

1969-01-01

162

Recent progress in development of infrared laser based instruments for real-time ambient measurements of isotopologues of carbon dioxide, water, methane, nitrous oxide and carbon monoxide  

NASA Astrophysics Data System (ADS)

The capacity for real time precise in situ measurements of isotopic ratios of a variety of trace gases at ambient concentrations continues to create new opportunities for the study of the exchanges and fluxes of gases in the environment. Aerodyne Research has made rapid progress in laser based instruments since our introduction in 2007 of the first truly field worthy instrument for real time measurements of isotopologues of carbon dioxide. We have focused on two instrument design platforms, with either one or two lasers. Absorption cells with more than 200 meters path length allow precise measurements of trace gases with low ambient concentrations. Most of our systems employ mid infrared quantum cascade lasers. However, recently available 3 micron antimonide based diode lasers are also proving useful for isotopic measurements. By substituting different lasers and detectors, we can simultaneously measure the isotopic composition of a variety of gases, including: H2O, CO2, CH4, N2O and CO. Our newest instrument for true simultaneous measurement of isotopologues of CO2 (12CO2, 13CO2, 12C18O16O) has (1 s) precision better than 0.1 per mil for both ratios. The availability of 10 Hz measurements allows measurement of isotopic fluxes via eddy correlation. The single laser instrument fits in a 19 inch rack and is only 25 cm tall. A two laser instrument is larger, but with that instrument we can also measure clumped isotopes of CO2, with 1 second precisions of: 2.3 per mil for 13C18O16O, and 6.7 per mil for 13C17O16O. The sample size for such a measurement corresponds to 0.2 micromole of pure CO2. Another variation on the two laser instrument simultaneously measures isotopologues of CO2 (12CO2, 13CO2, 12C18O16O) and H2O (H216O, H218O, HD16O). Preliminary results for water ratio precisions (in 1s) are 0.1 per mil for H218O and 0.3 per mil for HD16O, simultaneous (1 s) precisions for isotopologues of CO2 of ~0.1 per mil. Methane, nitrous oxide and carbon monoxide have such low ambient concentrations that real-time isotopologue measurements are a serious challenge. For these gases, we typically use our 200 m absorption cell. Several of these instruments have already been used for long term field measurements of isotopologues of methane, (12CH4, 13CH4), with a demonstrated (1 s) precision of 1.5 per mil. A new version of this instrument operating near 3.3 microns has recently been developed to quantify 13CH4 and CH3D simultaneously. In separate experiments at MIT, using trapped concentrated samples, we have made highly precise measurements of the abundance of the clumped isotope of methane: 13CH3D. We are also developing methods to monitor the isotopic abundance of the isotopes of CO and N2O. We have achieved a measurement precision for ambient 13CO (1 s) of 1.9 per mil. For the isotopologues of N2O (14N216O, 14N15N 16O, 15N14N 16O, 14N218O), we have demonstrated (1 s) precision at ambient levels (320 ppb) of ~3 per mil. For N2O, a quasi continuous preconcentrator has been used to give even better precisions (<0.1 per mil) and one is being developed for CO.

Nelson, David; McManus, Barry; Shorter, Joanne; Zahniser, Mark; Ono, Shuhei

2014-05-01

163

CARBON DIOXIDE AS A FEEDSTOCK.  

SciTech Connect

This report is an overview on the subject of carbon dioxide as a starting material for organic syntheses of potential commercial interest and the utilization of carbon dioxide as a substrate for fuel production. It draws extensively on literature sources, particularly on the report of a 1999 Workshop on the subject of catalysis in carbon dioxide utilization, but with emphasis on systems of most interest to us. Atmospheric carbon dioxide is an abundant (750 billion tons in atmosphere), but dilute source of carbon (only 0.036 % by volume), so technologies for utilization at the production source are crucial for both sequestration and utilization. Sequestration--such as pumping CO{sub 2} into sea or the earth--is beyond the scope of this report, except where it overlaps utilization, for example in converting CO{sub 2} to polymers. But sequestration dominates current thinking on short term solutions to global warming, as should be clear from reports from this and other workshops. The 3500 million tons estimated to be added to the atmosphere annually at present can be compared to the 110 million tons used to produce chemicals, chiefly urea (75 million tons), salicylic acid, cyclic carbonates and polycarbonates. Increased utilization of CO{sub 2} as a starting material is, however, highly desirable, because it is an inexpensive, non-toxic starting material. There are ongoing efforts to replace phosgene as a starting material. Creation of new materials and markets for them will increase this utilization, producing an increasingly positive, albeit small impact on global CO{sub 2} levels. The other uses of interest are utilization as a solvent and for fuel production and these will be discussed in turn.

CREUTZ,C.; FUJITA,E.

2000-12-09

164

Electrochemically regenerable carbon dioxide absorber  

NASA Technical Reports Server (NTRS)

Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

1979-01-01

165

Oxygen and carbon dioxide sensing  

NASA Technical Reports Server (NTRS)

A high electron mobility transistor (HEMT) capable of performing as a CO.sub.2 or O.sub.2 sensor is disclosed, hi one implementation, a polymer solar cell can be connected to the HEMT for use in an infrared detection system. In a second implementation, a selective recognition layer can be provided on a gate region of the HEMT. For carbon dioxide sensing, the selective recognition layer can be, in one example, PEI/starch. For oxygen sensing, the selective recognition layer can be, in one example, indium zinc oxide (IZO). In one application, the HEMTs can be used for the detection of carbon dioxide and oxygen in exhaled breath or blood.

Ren, Fan (Inventor); Pearton, Stephen John (Inventor)

2012-01-01

166

Mauna Loa Carbon Dioxide Record  

NSDL National Science Digital Library

The Mauna Loa atmospheric CO2 measurements constitute the longest continuous record of atmospheric CO2 concentrations available in the world. The Mauna Loa site is considered one of the most favorable locations for measuring undisturbed air because possible local influences are minimal. Methods and equipment used to obtain these measurements have remained essentially unchanged during the 47-year monitoring program. This easy to use dataset contains monthly averages of atmospheric carbon dioxide concentrations from 1958 through 2004.

Bollenbacher, A. F.; Keeling, Ralph F.; Piper, S. C.; Walker, Jeffrey S.

2010-07-05

167

Interpreting recent carbon dioxide data  

NSDL National Science Digital Library

Using web-accessed climate data, students will examine the latitudinal distribution of CO2 and explain how (and why) that has changed over (recent) time. They will then work in groups of two or three to download, graph, and interpret carbon dioxide concentration data from one individual location (different groups will be assigned a different site). Each student will complete a series of questions to ensure their understanding of the concepts outlined above.

Gordon, Elizabeth

168

Carbon Dioxide Removal via Passive Thermal Approaches  

NASA Technical Reports Server (NTRS)

A paper describes a regenerable approach to separate carbon dioxide from other cabin gases by means of cooling until the carbon dioxide forms carbon dioxide ice on the walls of the physical device. Currently, NASA space vehicles remove carbon dioxide by reaction with lithium hydroxide (LiOH) or by adsorption to an amine, a zeolite, or other sorbent. Use of lithium hydroxide, though reliable and well-understood, requires significant mass for all but the shortest missions in the form of lithium hydroxide pellets, because the reaction of carbon dioxide with lithium hydroxide is essentially irreversible. This approach is regenerable, uses less power than other historical approaches, and it is almost entirely passive, so it is more economical to operate and potentially maintenance- free for long-duration missions. In carbon dioxide removal mode, this approach passes a bone-dry stream of crew cabin atmospheric gas through a metal channel in thermal contact with a radiator. The radiator is pointed to reject thermal loads only to space. Within the channel, the working stream is cooled to the sublimation temperature of carbon dioxide at the prevailing cabin pressure, leading to formation of carbon dioxide ice on the channel walls. After a prescribed time or accumulation of carbon dioxide ice, for regeneration of the device, the channel is closed off from the crew cabin and the carbon dioxide ice is sublimed and either vented to the environment or accumulated for recovery of oxygen in a fully regenerative life support system.

Lawson, Michael; Hanford, Anthony; Conger, Bruce; Anderson, Molly

2011-01-01

169

Carbon dioxide review 1982  

SciTech Connect

The buildup of CO/sub 2/ is a reality, monitored with increasing precision since 1957 and inferred for much earlier dates. A statistical section gives the monitored values to 1980, as well as a review of a long series of measurements made at Mauna Loa by the pioneers of such monitoring, Charles D. Keeling, Robert B. Bacastow, and Timothy P. Whorf. The book discusses internal transport processes in the ocean, of ocean-atmosphere interaction, of the magnitude of forest and soil carbon wastage, of the future course of fossil-fuel consumption. Yet something else emerges, too: if the CO/sub 2/ buildup continues; if the big general circulation models are right about its impact on climate, and if we have not miscalculated the potential role of the oceans, then we face a climatic change in the next century and a half like nothing the post-glacial world, and hence civilized humanity, has seen.

Clark, W.C. (ed.)

1982-01-01

170

Solubility of Carbon Dioxide in Water.  

ERIC Educational Resources Information Center

Describes an activity measuring the amount of dissolved carbon dioxide in carbonated water at different temperatures. The amount of carbon dioxide is measured by the amount of dilute ammonia solution needed to produce a pH indicator color change. (PR)

Bush, Pat; And Others

1992-01-01

171

Carbon dioxide equilibria and their applications  

Microsoft Academic Search

Carbon dioxide, bicarbonate ion, and carbonate ion comprise the most important acid-base system in natural waters, and the equilibria between them regulate the pH of seawater, as well as most rainwater, stream water, river water, and groundwater. Carbon Dioxide Equilibria and Their Applications provides a clear, compact presentation of this topic, which is central to geochemistry and environmental engineering. It

1992-01-01

172

Closed carbon dioxide filtration revisited.  

PubMed

There are compelling reasons why the closed carbon dioxide filtration method for inhalation anaesthesia deserves serious reconsideration. Use of the closed absorption system today can provide all the benefits recognised by those who introduced it seventy to eighty years ago. A most important benefit is the increased opportunity of learning afforded the user, which leads either neophyte or senior clinician to improvement of both concept and clinical skills. The current resurgence of interest is fully appropriate for all physicians who aspire to be true specialists in the care of patients during clinical anaesthesia. PMID:7978194

Morris, L E

1994-08-01

173

Sorption of carbon dioxide onto sodium carbonate  

SciTech Connect

Sodium carbonate was used as a sorbent to capture CO{sub 2} from a gaseous stream of carbon dioxide, nitrogen, and moisture. The breakthrough data of CO{sub 2} were measured in a fixed bed to observe the reaction kinetics of CO{sub 2}-carbonate reaction. Several models such as the shrinking-core model, the homogeneous model, and the deactivation model in the non-catalytic heterogeneous reaction systems were used to explain the kinetics of reaction among CO{sub 2}, Na{sub 2}CO{sub 3}, and moisture using analysis of the experimental breakthrough data. Good agreement of the deactivation model was obtained with the experimental breakthrough data. The sorption rate constant and the deactivation rate constant were evaluated by analysis of the experimental breakthrough data using a nonlinear least squares technique and described as Arrhenius form.

Sang-Wook Park; Deok-Ho Sung; Byoung-Sik Choi; Kwang-Joong Oh; Kil-Ho Moon [Pusan National University, Busan (Republic of Korea). Division of Chemical Engineering

2006-07-01

174

SEQUESTERING CARBON DIOXIDE IN COALBEDS  

SciTech Connect

The authors' long term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure and adsorbent types. The major objectives of the project are to: (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coal being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals, to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. The specific accomplishments of this project during this reporting period are summarized below in three broad categories outlining experimentation, model development, and coal characterization. (1) Experimental Work: Our adsorption apparatus was reassembled, and all instruments were tested and calibrated. Having confirmed the viability of the experimental apparatus and procedures used, adsorption isotherms for pure methane, carbon dioxide and nitrogen on wet Fruitland coal were measured at 319.3 K (115 F) and pressures to 12.4 MPa (1800 psia). These measurements showed good agreement with our previous data and yielded an expected uncertainty of about 2%. Preparations are underway to measure adsorption isotherms for pure methane, carbon dioxide and nitrogen on two other coals. (2) Model Development: The experimental data were used to evaluate the predictive capabilities of various adsorption models, including the Langmuir/loading ratio correlation, two-dimensional cubic equations of state, and the local density model. In general, all models performed well for Type I adsorption exhibited by methane, nitrogen, and carbon dioxide up to 8.3 MPa (average deviations within 2%). However, for pressures higher than 8.3 MPa (1200 psia), carbon dioxide produced multilayer adsorption behavior similar to Type IV adsorption. Our results to date indicate that the SLD model may be a suitable choice for modeling multilayer coalbed gas adsorption. However, model improvements are required to (a) account for coal heterogeneity and structure complexity, and (b) provide for more accurate density predictions. (3) Coal Characterization: We have identified several well-characterized coals for use in our adsorption studies. The criteria for coal selection has been guided by the need for coals that (a) span the spectrum of properties encountered in coalbed methane production (such as variation in rank), and (b) originate from coalbed methane recovery sites (e.g., San Juan Basin, Black Warrior Basin, etc.). At Pennsylvania State University, we have completed calibrating our instruments using a well-characterized activated carbon. In addition, we have conducted CO{sub 2} and methane uptakes on four samples, including (a) a widely used commercial activated carbon, BPL from Calgon Carbon Corp.; (b) an Illinois No.6 bituminous coal from the Argonne Premium Coal sample bank; (c) a Fruitland Intermediate coal sample; (d) a dry Fruitland sample. The results are as expected, except for a greater sensitivity to the outgassing temperature. ''Standard'' outgassing conditions (e.g., 383.2 K, overnight), which are often used, may not be appropriate for gas storage in coalbeds. Conditions that are more representative of in-situ coal (approximately 313.2 K) may be much more appropriate. In addition, our results highlight the importance of assessing the degree of approach to adsorption equilibrium.

K.A.M. Gasem; R.L. Robinson, Jr.; L.R. Radovic

2001-06-15

175

27 CFR 24.319 - Carbon dioxide record.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 false Carbon dioxide record. 24.319...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...and Reports § 24.319 Carbon dioxide record. A proprietor who uses carbon dioxide in still...

2009-04-01

176

27 CFR 24.319 - Carbon dioxide record.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Carbon dioxide record. 24.319...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...and Reports § 24.319 Carbon dioxide record. A proprietor who uses carbon dioxide in still...

2010-04-01

177

46 CFR 76.15-20 - Carbon dioxide storage.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Carbon dioxide storage. 76.15-20 Section 76.15-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...Carbon Dioxide Extinguishing Systems, Details § 76.15-20 Carbon dioxide storage. (a)...

2013-10-01

178

Carbon Dioxide Reduction with Alkali-Metal Amalgams.  

National Technical Information Service (NTIS)

The reduction of carbon dioxide by alkali-metal amalgams was studied as a potential means for reclamation of carbon dioxide waste gas in space systems. The carbon dioxide reduction reactions were investigated at moderate temperatures and pressures - typic...

C. M. Cox R. W. Treharne

1968-01-01

179

CARBON DIOXIDE AND OUR OCEAN LEGACY  

Microsoft Academic Search

Global warming is increasing ocean tempera- tures and raising sea levels. New scientific research shows that our oceans are beginning to face yet another threat due to global warm- ing-related emissions - their basic chemistry is changing because of the uptake of carbon dioxide released by human activities. When carbon dioxide is absorbed by the oceans it reacts with seawater

Richard A. Feely; Christopher L. Sabine; Victoria J. Fabry

180

Electrochemical processing of carbon dioxide.  

PubMed

With respect to the negative role of carbon dioxide on our climate, it is clear that the time is ripe for the development of processes that convert CO(2) into useful products. The electroreduction of CO(2) is a prime candidate here, as the reaction at near-ambient conditions can yield organics such as formic acid, methanol, and methane. Recent laboratory work on the 100 A scale has shown that reduction of CO(2) to formate (HCO(2)(-)) may be carried out in a trickle-bed continuous electrochemical reactor under industrially viable conditions. Presuming the problems of cathode stability and formate crossover can be overcome, this type of reactor is proposed as the basis for a commercial operation. The viability of corresponding processes for electrosynthesis of formate salts and/or formic acid from CO(2) is examined here through conceptual flowsheets for two process options, each converting CO(2) at the rate of 100 tonnes per day. PMID:18702129

Oloman, Colin; Li, Hui

2008-01-01

181

Microfluidic studies of carbon dioxide.  

PubMed

Carbon dioxide (CO2 ) sequestration, storage and recycling will greatly benefit from comprehensive studies of physical and chemical gas-liquid processes involving CO2 . Over the past five years, microfluidics emerged as a valuable tool in CO2 -related research, due to superior mass and heat transfer, reduced axial dispersion, well-defined gas-liquid interfacial areas and the ability to vary reagent concentrations in a high-throughput manner. This Minireview highlights recent progress in microfluidic studies of CO2 -related processes, including dissolution of CO2 in physical solvents, CO2 reactions, the utilization of CO2 in materials science, and the use of supercritical CO2 as a "green" solvent. PMID:24961230

Abolhasani, Milad; Gnther, Axel; Kumacheva, Eugenia

2014-07-28

182

How Is Carbon Dioxide Measured?  

NSDL National Science Digital Library

In this textbook chapter, scientists studying the concentration of becomes CO² in the atmosphere are profiled. The techniques for measuring and recording carbon dioxide concentrations at the Mauna Loa Observatory are described. A link to a video clip of an interview with NOAA scientist Dr. Pieter Tans is included. This is the fifth chapter in the unit, Climate Change, which addresses the question of how human activities are changing Earth's climate. The resource includes three classroom investigations, links to current news articles, and a suite of pre and post unit assessments. A teacher's guide supports classroom use. The resource is part of Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

183

Carbon dioxide capture process with regenerable sorbents  

DOEpatents

A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate. Spent sorbent containing the bicarbonate or carbonate is moved to a second reactor where it is heated or treated with a reducing agent such as, natural gas, methane, carbon monoxide hydrogen, or a synthesis gas comprising of a combination of carbon monoxide and hydrogen. The heat or reducing agent releases carbon dioxide gas and regenerates the active material for use as the sorbent material in the first reactor. New sorbent may be added to the regenerated sorbent prior to subsequent passes in the carbon dioxide removal reactor.

Pennline, Henry W. (Bethel Park, PA); Hoffman, James S. (Library, PA)

2002-05-14

184

SEQUESTERING CARBON DIOXIDE IN COALBEDS  

SciTech Connect

During the present reporting period, six complementary tasks involving experimentation, model development, and coal characterization were undertaken to meet our project objectives: (1) A second adsorption apparatus, utilizing equipment donated by BP Amoco, was assembled. Having confirmed the reliability of this additional experimental apparatus and procedures, adsorption isotherms for CO{sub 2}, methane, ethane, and nitrogen on wet Fruitland coal and on activated carbon were measured at 319.3 K (115 F) and pressures to 12.4 MPa (1800 psia). These measurements showed good agreement with our previous data and yielded an expected uncertainty of about 3%. The addition of this new facility has allowed us to essentially double our rate of data production. (2) Adsorption isotherms for pure CO{sub 2}, methane, and nitrogen on wet Illinois-6 coal and on activated carbon were measured at 319.3 K (115 F) and pressures to 12.4 MPa (1800 psia) on our first apparatus. The activated carbon measurements showed good agreement with literature data and with measurements obtained on our second apparatus. The expected uncertainty of the data is about 3%. The Illinois-6 adsorption measurements are a new addition to the existing database. Preparations are underway to measure adsorption isotherms for pure methane, carbon dioxide and nitrogen on DESC-8 coal. (3) Adsorption from binary mixtures of methane, nitrogen and CO{sub 2} at a series of compositions was also measured on the wet Fruitland coal at 319.3 K (115 F), using our first apparatus. The nominal compositions of these mixtures are 20%/80%, 40%/60%, 60%/40%, and 80%/20%. The experiments were conducted at pressures from 100 psia to 1800 psia. The expected uncertainty for these binary mixture data varies from 2 to 9%. (4) A study was completed to address the previously-reported rise in the CO{sub 2} absolute adsorption on wet Fruitland coal at 115 F and pressures exceeding 1200 psia. Our additional adsorption measurements on Fruitland coal and on activated carbon show that: (a) the Gibbs adsorption isotherm for CO{sub 2} under study exhibits typical adsorption behavior for supercritical gas adsorption, and (b) a slight variation from Type I absolute adsorption may be observed for CO{sub 2}, but the variation is sensitive to the estimates used for adsorbed phase density. (5) The experimental data were used to evaluate the predictive capabilities of various adsorption models, including the Langmuir/loading ratio correlation, a two-dimensional cubic equation of state (EOS), a new two-dimensional (2-D) segment-segment interactions equation of state, and the simplified local density model (SLD). Our model development efforts have focused on developing the 2-D analog to the Park-Gasem-Robinson (PGR) EOS and an improved form of the SLD model. The new PGR EOS offers two advantages: (a) it has a more accurate repulsive term, which is important for reliable adsorption predictions, and (b) it is a segment-segment interactions model, which should more closely describe the gas-coal interactions during the adsorption process. In addition, a slit form of the SLD model was refined to account more precisely for heterogeneity of the coal surface and matrix swelling. In general, all models performed well for the Type I adsorption exhibited by methane, nitrogen, and carbon dioxide up to 8.3 MPa (average deviations within 2%). In comparison, the SLD model represented the adsorption behavior of all fluids considered within 5% average deviations, including the near-critical behavior of carbon dioxide beyond 8.3 MPa (1200 psia). Work is in progress to (a) derive and implement the biporous form of the SLD model, which would expand the number of structural geometries used to represent the heterogeneity of coal surface; and (b) extend the SLD model to mixture predictions. (6) Proper reduction of our adsorption data requires accurate gas-phase compressibility (Z) factors for methane, ethane, nitrogen and carbon dioxide and their mixtures to properly analyze our experimental adsorption data. A careful evaluation of t

K.A.M. Gasem; R.L. Robinson, Jr.; L.R. Radovic

2001-06-15

185

Adipose-derived stem cells cooperate with fractional carbon dioxide laser in antagonizing photoaging: a potential role of Wnt and ?-catenin signaling  

PubMed Central

Background It is well established that adipose-derived stem cells (ADSCs) produce and secrete cytokines/growth factors that antagonize UV-induced photoaging of skin. However, the exact molecular basis underlying the anti-photoaging effects exerted by ADSCs is not well understood, and whether ADSCs cooperate with fractional carbon dioxide (CO2) laser to facilitate photoaging skin healing process has not been explored. Here, we investigated the impacts of ADSCs on photoaging in a photoaging animal model, its associated mechanisms, and its functional cooperation with fractional CO2 laser in treatment of photoaging skin. Results We showed that ADSCs improved dermal thickness and activated the proliferation of dermal fibroblast. We further demonstrated that the combined treatment of ADSCs and fractional CO2 laser, the latter which is often used to resurface skin and treat wrinkles, had more beneficial effects on the photoaging skin compared with each individual treatment. In our prepared HDF photoaging model, flow cytometry showed that, after adipose derived stem cells conditioned medium (ADSC-CM) co-cultured HDF photoaging model, the cell proliferation rate is higher than UVB irradiation induced HDF modeling (p?laser treatment. And the expression of wnt3a and ?-catenin has the positive correlation with photoaging related protein TGF-?2 and COLI. We also verified these protein expressions in tissue level. In addition, after injected SFRP2 into ADSC-CM co-cultured HDF photoaging model, wnt3a inhibitor, compared with un-intervened group, wnt3a, ?-catenin protein level significantly decreased. Conclusion Both ADSCs and fractional CO2 laser improved photoaging skin at least partially via targeting dermal fibroblast activity which was increased in photoaging skin. The combinatorial use of ADSCs and fractional CO2 laser synergistically improved the healing process of photoaging skin. Thus, we provide a strong rationale for a combined use of ADSCs and fractional CO2 laser in treatment of photoaging skin in clinic in the future. Moreover, we provided evidence that the Wnt/?-catenin signaling pathway may contribute to the activation of dermal fibroblast by the transplantation of ADSCs in both vitro and vivo experiment.

2014-01-01

186

Photolytical Generation of Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Carbon dioxide has been found by Cassini VIMS throughout the Saturnian system in locations such as Iapetus' equator where the temperature is too high for it to remain as free ice for more than a few hundred years. We suggest that the 4.26 micron absorption feature found on Iapetus and Hyperion (that has been attributed to complexed CO2) is the result of either UV photolysis or ion bombardment driving chemistry between the carbon rich layer and the water ice regolith. We conducted experiments to simulate the generation of CO2 by UV radiation under conditions similar to those on the surface of Iapetus. A simulated icy regolith was created in an argon atmosphere using flash-frozen, degassed water crushed into sub-millimeter sized particles. Isotopically labeled amorphous carbon (13C), which was ground into a fine dust, was mixed into the regolith allowing for extensive grain contact. This sample was placed in a vacuum chamber and cooled to temperatures as low at 60K. The sample was irradiated with UV light, and the products were measured using both a mass spectrometer to identify free molecules and an IR spectrometer for molecules that remained trapped on and in the simulated regolith. We report on the production and reaction rates of CO2 and CO, as well as the generation of free hydrogen and oxygen as detected by a SRS-100 mass spectrometer. We also identify residual products that either freeze on the surface or become entrained by or adsorbed onto the ice grains. We attempt to match the CO2 absorption feature found on Iapetus with that seen in our simulation, perhaps identifying a possible source of CO2 in the Saturnian system. Finally, we estimate the time required for these reactions to occur on Iapetus to see if UV photolysis would be effective.

Palmer, E. E.; Brown, R. H.

2008-12-01

187

Adsorption of Carbon Dioxide on Chemically Modified Carbon Adsorbents  

Microsoft Academic Search

Carbon adsorbents were chemically modified to have base sites on their surfaces, and the adsorption characteristics of carbon dioxide on them were investigated. Three kinds of carbon materials were used as support materials: two activated carbons and a carbon black. Base sites were introduced by impregnating the support materials with calcium acetate solution, followed by calcination at 700C for 2

Hyun-K Song; Kun-Hing Lee

1998-01-01

188

Silver oxide sorbent for carbon dioxide  

NASA Technical Reports Server (NTRS)

Material can be regenerated at least 20 times by heating at 250 C. Sorbent is compatible with environment of high humidity; up to 20% by weight of carbon dioxide can be absorbed. Material is prepared from silver carbonate, potassium hydroxide or carbonate, and sodium silicate.

Colombo, G. V.

1974-01-01

189

Global Deforestation: Contribution to Atmospheric Carbon Dioxide  

Microsoft Academic Search

A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1860 and 1980 was between 135 1015 and 228 1015 grams. Between 1.8 1015 and 4.7 1015 grams of carbon were released in 1980, of which nearly

G. M. Woodwell; J. E. Hobbie; R. A. Houghton; J. M. Melillo; B. Moore; B. J. Peterson; G. R. Shaver

1983-01-01

190

LIFETIME OF EXCESS ATMOSPHERIC CARBON DIOXIDE  

EPA Science Inventory

We explore the effects of a changing terrestrial biosphere on the atmospheric residende time of carbon dioxide using three simple ocean carbon cycling models and a model of global terrestrial carbon cycling. e find differences in model behavior associated with the assumption of a...

191

Carbon Dioxide Absorption and Desorption by Tris with Carbonic Anhydrase.  

National Technical Information Service (NTIS)

One concept of carbon dioxide control in aerospace vehicle atmosphere regeneration and control requires an efficient gas absorber which is effective in a moist gas stream. A tris (tri(hydroxymethyl)aminomethane) solution containing the enzyme, carbonic an...

J. P. Allen

1967-01-01

192

Fractional carbon dioxide laser-assisted drug delivery of topical timolol solution for the treatment of deep infantile hemangioma: a pilot study.  

PubMed

Infantile hemangiomas (IHs) are benign vascular tumors of infancy. Topical timolol has recently been reported to be an effective treatment for superficial IHs, although it failed to have an effect on deep IHs. This prospective study was aimed at evaluating the feasibility of ablative fractional laser-assisted drug delivery for enhancing topical timolol permeation into deep IHs. Nine patients ages 1 to 6 months with deep IHs were enrolled. A fractional carbon dioxide (CO2 ) laser system was applied to the skin surface of deep IHs using the DeepFx mode (25-30 mJ/pulse, 5% density, single pulse) at 1-week intervals. Topical timolol maleate 0.5% ophthalmic solution was applied under occlusion for 30 minutes four to five times per day for an average treatment duration of 14.2 weeks. Clinical improvement was evaluated according to a global score and the Hemangioma Activity Score (HAS). Four patients (44.4%) demonstrated excellent regression, four (44.4%) showed good response, and one (11.1%) experienced moderate regression. The HAS declined from 4.1 0.7 at baseline to 1.7 0.7 at 1 week (p < 0.001) and 1.4 0.7 at 3 months (p = 0.03) after the last treatment procedure. Plasma timolol concentration was not detected in any of the patients after the first administration of topical timolol. No systemic complication or skin side effects were observed in any of the patients. Ablative fractional laser-assisted transdermal delivery of topical timolol is a safe and effective method for the treatment of deep IHs. PMID:24602019

Ma, Gang; Wu, Pinru; Lin, Xiaoxi; Chen, Hui; Hu, Xiaojie; Jin, Yunbo; Qiu, Yajing

2014-01-01

193

Carbon dioxide dynamics in Kelud volcanic lake  

NASA Astrophysics Data System (ADS)

In November 2007, the extrusion of a new lava dome evaporated Kelud volcanic lake in Java, Indonesia. Four months before a detailed echo sounding survey of the volcanic lake coupled to floating accumulation chamber measurements detected abnormally high carbon dioxide emissions. It constituted the earliest sign of the volcanic unrest; well before any other monitored parameter. CO2 flux is quantified using an empirical equation based on the volume of bubbles backscattered in the water column. Its comparison with the fluxes retrieved from the floating chamber method better constrain carbon dioxide dynamics in the volcanic lake. It reveals that 70% of the carbon dioxide enters the lake in a dissolved form, while the remaining 30% is supplied to the lake on a gaseous state. Almost three-quarter of the ascending bubbles dissolve in the water column leaving the majority of the 330 Tons day-1 of carbon dioxide diffusing at the air-water interface.

Caudron, C.; Mazot, A.; Bernard, A.

2012-05-01

194

Electrochemical Carbon Dioxide Concentrator Subsystem Development.  

National Technical Information Service (NTIS)

The fabrication of a one-person Electrochemical Depolarized Carbon Dioxide Concentrator subsystem incorporating advanced electrochemical, mechanical, and control and monitor instrumentation concepts is discussed. This subsystem included an advanced liquid...

D. B. Heppner, M. J. Dahlausen, F. H. Schubert

1983-01-01

195

Carbon Dioxide Emission Factors for Coal  

EIA Publications

The Energy Information Administration (EIA) has developed factors for estimating the amount of carbon dioxide emitted, accounting for differences among coals, to reflect the changing "mix" of coal in U.S. coal consumption.

William Watson

1994-08-01

196

Biochemical Capture and Removal of Carbon Dioxide.  

National Technical Information Service (NTIS)

We devised an enzyme-based facilitated transport membrane bioreactor system to selectively remove carbon dioxide (CO2) from the space station environment. We developed and expressed site-directed enzyme mutants for CO2 capture. Enzyme kinetics showed the ...

M. C. Trachtenberg

1998-01-01

197

Cost Analysis of Carbon Dioxide Concentrators.  

National Technical Information Service (NTIS)

A methodology is developed to predict the relevant contributions of the more intangible cost elements encountered in the development of flight-qualified hardware and is used to predict the costs of three carbon dioxide concentration systems. The cost and ...

M. M. Yakut

1972-01-01

198

Carbon Dioxide Catastrophes: Past and Future Menace.  

National Technical Information Service (NTIS)

Carbon dioxide is important in its role as coupler of the terrestrial biosphere to inorganic chemical processes and as the principal greenhouse gas controlling Earth's surface temperature. The hypothesis that atmospheric CO2 levels have diminished with ti...

M. E. Baur

1988-01-01

199

Testing carbon sequestration site monitor instruments using a controlled carbon dioxide release facility  

Microsoft Academic Search

Two laser-based instruments for carbon sequestration site monitoring have been developed and tested at a controlled carbon dioxide CO2 release facility. The first instrument uses a temperature tunable distributed feedback (DFB) diode laser capable of accessing the 2.0027-2.0042 m spectral region that contains three CO2 absorption lines and is used for aboveground atmospheric CO2 concentration mea- surements. The second instrument

Seth D. Humphries; Amin R. Nehrir; Charlie J. Keith; Kevin S. Repasky; Laura M. Dobeck; John L. Carlsten; Lee H. Spangler

2008-01-01

200

Role of activated carbon pellets in carbon dioxide removal  

Microsoft Academic Search

The removal of carbon dioxide from gas\\/air streams is more often becoming necessary in many industries for different purposes. In cryogenic air separation plant, air has to be free from carbon dioxide before its liquefaction otherwise blockage due to freezing of heat exchange equipment would result. Enrichment of methane in biogas to have fuel of higher calorific value can be

S. C Sarkar; A Bose

1997-01-01

201

Mitigating strategies for carbon dioxide problems  

SciTech Connect

Society can take steps to enhance our ability to adapt more easily to carbon dioxide induced changes. Given the rapidity of social and technological change in the twentieth century, facilitating adjustment is important. With the exception of data collection and analysis focused on climate, enhancing each of these functions will be to the general benefit of society, but will not be unique to carbon dioxide-induced problems. Carbon dioxide issues can provide a rationale, but more probably will be a catalyst, for pushing society to enhance its ability to adapt to and exploit change. Carbon dioxide is but one of many factors which will have an enormous impact on the economic and social institutions of the United States in the twenty-first century. If carbon dioxide-induced changes were as large as now appears possible, and if they were the only major change, then it would be worthwhile to invest in enhancing education and capital formation so that we could minimize the effects of adverse changes and take advantage of beneficial ones. Since carbon dioxide-induced changes are likely to be only one, possibly small, source of change, there is all the more reason to devote resources to making our economic and social institutions more flexible and adaptable. 7 references.

Lave, L.B.

1982-05-01

202

Mineralization strategies for carbon dioxide sequestration  

SciTech Connect

Progress is reported in three primary research areas--each concerned with sequestering carbon dioxide into mineral matrices. Direct mineral carbonation was pioneered at Albany Research Center. The method treats the reactant, olivine or serpentine in aqueous media with carbon dioxide at high temperature and pressure to form stable mineral carbonates. Recent results are introduced for pretreatment by high-intensity grinding to improve carbonation efficiency. To prove feasibility of the carbonation process, a new reactor was designed and operated to progress from batch tests to continuous operation. The new reactor is a prototype high-temperature, high-pressure flow loop reactor that will furnish information on flow, energy consumption, and wear and corrosion resulting from slurry flow and the carbonation reaction. A promising alternative mineralization approach is also described. New data are presented for long-term exposure of carbon dioxide to Colombia River Basalt to determine the extent of conversion of carbon dioxide to permanent mineral carbonates. Batch autoclave tests were conducted using drill-core samples of basalt and reacted under conditions that simulate in situ injection into basalt-containing geological formations.

Penner, Larry R.; O'Connor, William K.; Gerdemann, Stephen J.; Dahlin, David C.

2003-01-01

203

Uncertainty analysis for the miniaturized laser heterodyne radiometer (mini-LHR) for the measurement of carbon dioxide in the atmospheric column  

NASA Astrophysics Data System (ADS)

Presented here is a sensitivity analysis for the miniaturized laser heterodyne radiometer. This passive, ground-based instrument measures carbon dioxide (CO2) in the atmospheric column and has been under development at NASA/GSFC since 2009. The goal of this development is to produce a low-cost, easily-deployable instrument that can extend current ground measurement networks in order to (1) validate column satellite observations, (2) provide coverage in regions of limited satellite observations, (3) target regions of interest such as thawing permafrost, and (4) support the continuity of a long-term climate record. In this paper an uncertainty analysis of the instrument performance is presented and compared with results from three sets of field measurements. The signal-to-noise ratio (SNR) and corresponding maximum uncertainty for a single scan are calculated to be 329.4 1.3 by deploying error propagation through the equation governing the SNR. Reported is an absorbance noise of 0.0024 for six averaged scans of field data, for an instrument precision of 0.14 ppmv for CO2.

Clarke, G. B.; Wilson, E. L.; Miller, J. H.; Melroy, H. R.

2014-05-01

204

Treatment of Acne Scars and Wrinkles in Asian Patients Using Carbon-Dioxide Fractional Laser Resurfacing: Its Effects on Skin Biophysical Profiles  

PubMed Central

Background Although ablative fractional resurfacing is known to be effective against photoaging and acne scars, studies on its efficacy, safety and changes in the skin characteristics of Asians are limited. Objective The aim of this study is to assess the efficacy and safety of carbon dioxide fractional laser (CO2FL) in Koreans treated for wrinkles and acne scars, and to define the changes in skin characteristics during recovery period. Methods We administered one session of CO2FL on 10 acne scar patients and 14 wrinkles patients with skin types IV and V. The surveillance of efficacy and side effects along with the measurement of biophysical properties was carried out before 1 day, 1 week, 1 month and 3 months after treatment. Results Using a non-invasive method, skin barrier damage, erythema and bronzing of skin during the recovery period were assessed, and all of the items eventually returned to the pre-treatment level. Skin elasticity was measured in the wrinkle group, and the statistically significant effect was sustained throughout the next three months. The outcome of treatment was found to be better than 'moderate improvement' in both the acne scar and wrinkle groups. Further, there were no serious side effects three months post-procedure. Conclusion CO2 FL is thought to be an effective and safe method for treating moderate to severe acne scars and wrinkles in Asians.

Hwang, Young Ji; Lee, Yu Na; Choe, Yong Beom; Ahn, Kyu Joong

2013-01-01

205

Monitoring annealing via carbon dioxide laser heating of defect populations in fused silica surfaces using photoluminescence microscopy  

SciTech Connect

Photoluminescence (PL) microscopy and spectroscopy under 266 nm and 355 nm laser excitation are explored as a means of monitoring defect populations in laser-modified sites on the surface of fused silica and their subsequent response to heating to different temperatures via exposure to a CO{sub 2} laser beam. Laser-induced temperature changes were estimated using an analytic solution to the heat flow equation and compared to changes in the PL emission intensity. The results indicate that the defect concentrations decrease significantly with increasing CO{sub 2} laser exposure and are nearly eliminated when the peak surface temperature exceeds the softening point of fused silica ({approx}1900K), suggesting that this method might be suitable for in situ monitoring of repair of defective sites in fused silica optical components.

Raman, R N; Matthews, M J; Adams, J J; Demos, S G

2010-02-01

206

Carbon dioxide sequestration by ex-situ mineral carbonation  

Microsoft Academic Search

The process developed for carbon dioxide sequestration utilizes a slurry of water mixed with olivine- forsterite end member (MgSiO), which is reacted with supercritical CO to produce magnesite (MgCO). Carbon dioxide is dissolved in water to form carbonic acid, which likely dissociates to H{sup +} and HCO⁻. The H{sup +} hydrolyzes the silicate mineral, freeing the cation (Mg{sup 2+}), which

W. K. OConnor; D. C. Dahlin; P. C. Turner

2000-01-01

207

Infrared heterodyne spectrometer measurements of vertical profile of tropospheric ammonia and ozone. [using dual carbon dioxide laser  

NASA Technical Reports Server (NTRS)

Remote sensing of the concentration and vertical distribution of atmospheric gases has been carried out using a dual CO2 laser multichannel infrared heterodyne spectrometer (IHS). The high specificity and nearly quantum-noise-limited sensitivity of the IHS provide the capability of scanning individual signature lines of selected atmospheric constituents in the 9 to 11 micron region. A comprehensive investigation of the spectral overlap between CO2 laser local oscillator transitions and selected atmospheric constituents was performed; measurements of the atmospheric absorption of solar radiation from the ground were carried out at selected laser transitions for ammonia and ozone.

Peyton, B. J.; Lange, R. A.; Savage, M. G.; Seals, R. K.; Allario, F.

1977-01-01

208

Preliminary Study on Pain Reduction of Monosodium Iodoacetate-Induced Knee Osteoarthritis in Rats by Carbon Dioxide Laser Moxibustion  

PubMed Central

In order to study the effects of CO2 laser moxibustion on the pain and inflammatory cytokine expression in the spinal dorsal horn of rats with monosodium iodoacetate- (MIA-) induced knee osteoarthritis (KOA), we designed an experiment by randomly assigning 8 SD rats into 3 groups, namely, a CO2 laser moxibustion group, a sham treatment group, and a blank control group. The treatment group received a laser moxibustion on acupoint Dubi (ST 35; 5?min/treatment, 1 treatment/day) for 8 days, and after treatment, the rats exhibited significantly increased interhindpaw differences compared with their preinduction values. Meanwhile, cytokine microarray analysis showed that one cytokine (TIMP-1) was significantly upregulated and two cytokines (Agrin and MMP-8) were significantly downregulated in treatment group. The present study suggested that CO2 laser moxibustion created certain pain reduction in the rats with MIA-induced KOA and significantly inhibited the expression of most inflammatory cytokines in the ipsilateral spinal dorsal horn.

Wu, Fan; Zhang, Ruixing; Shen, Xueyong; Lao, Lixing

2014-01-01

209

Carbon Dioxide- Where Does it All Go?  

NSDL National Science Digital Library

In this problem set, learners will use a diagram of carbon fluxes, which shows the sources that contribute to current atmospheric carbon dioxide levels, to answer a series of questions. Answer key is provided. This problem is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

210

Method for extracting and sequestering carbon dioxide  

DOEpatents

A method and apparatus to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said method and apparatus hydrates CO.sub.2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Rau, Gregory H. (Castro Valley, CA); Caldeira, Kenneth G. (Livermore, CA)

2005-05-10

211

Apparatus for extracting and sequestering carbon dioxide  

DOEpatents

An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Rau, Gregory H. (Castro Valley, CA); Caldeira, Kenneth G. (Livermore, CA)

2010-02-02

212

Method for Extracting and Sequestering Carbon Dioxide  

DOEpatents

A method and apparatus to extract and sequester carbon dioxide (CO2) from a stream or volume of gas wherein said method and apparatus hydrates CO2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO2 from a gaseous environment.

Rau, Gregory H.; Caldeira, Kenneth G.

2005-05-10

213

ELECTRODISPERSION OF FINE AQUEOUS DROPLETS IN SUPERCRITICAL CARBON DIOXIDE  

Microsoft Academic Search

This first study of electrospraying of a liquid into a dense, supercritical fluid has demonstrated a new method for dispersing aqueous liquid into supercritical carbon dioxide (SC-CO2) using pulsed high-voltage electric fields. The electrodispersion cell (EDC) was equipped with a laser light scattering system to determine the dependence of mean droplet size on operating variables such as field strength, pulse

K. D. Heath; H. D. Cochran

2001-01-01

214

SEQUESTERING CARBON DIOXIDE IN COALBEDS  

SciTech Connect

The authors' long-term goal is to develop accurate prediction methods for describing the adsorption behavior of gas mixtures on solid adsorbents over complete ranges of temperature, pressure and adsorbent types. The originally-stated, major objectives of the current project are to (1) measure the adsorption behavior of pure CO{sub 2}, methane, nitrogen, and their binary and ternary mixtures on several selected coals having different properties at temperatures and pressures applicable to the particular coals being studied, (2) generalize the adsorption results in terms of appropriate properties of the coals to facilitate estimation of adsorption behavior for coals other than those studied experimentally, (3) delineate the sensitivity of the competitive adsorption of CO{sub 2}, methane and nitrogen to the specific characteristics of the coal on which they are adsorbed; establish the major differences (if any) in the nature of this competitive adsorption on different coals, and (4) test and/or develop theoretically-based mathematical models to represent accurately the adsorption behavior of mixtures of the type for which measurements are made. As this project has developed, an important additional objective has been added to the above original list. Namely, we have been encouraged to interact with industry and/or governmental agencies to utilize our expertise to advance the state of the art in coalbed adsorption science and technology. As a result of this additional objective, we have participated with the Department of Energy and industry in the measurement and analysis of adsorption behavior as part of two distinct investigations. These include (a) Advanced Resources International (ARI) DOE Project DE-FC26-00NT40924, ''Adsorption of Pure Methane, Nitrogen, and Carbon Dioxide and Their Mixtures on Wet Tiffany Coal'', and (b) the DOE-NETL Project, ''Round Robin: CO{sub 2} Adsorption on Selected Coals''. These activities, contributing directly to the DOE projects listed above, have also provided direct synergism with the original goals of our work. Specific accomplishments of this project during the current reporting period are summarized in three broad categories outlining experimentation, model development, and coal characterization.

K.A.M. Gasem; R.L. Robinson, Jr.; L.R. Radovic

2003-03-10

215

BRIEF COMMUNICATIONS: Carbon dioxide gasdynamic laser utilizing combustion C2H2CON2O -N2 mixtures  

Microsoft Academic Search

Measurements were made of the gain Ko of a CO2 gasdynamic laser utilizing the combustion products of C2H2-pCO-(5 + n)N2O-mN2 mixtures. The gain was Koapprox1m-1 at Toapprox1600-2000K. It was found that fuel combinations of the C2H2-3N2O-mN2 type could be used in gasdynamic lasers with selective excitation of the working gas. Bibtex entry for this abstract Preferred format for this abstract

N. V. Evtyukhin

1980-01-01

216

A wide angle search technique for a 10.6 micron ladar. [scanning radar using Q switched carbon dioxide laser  

NASA Technical Reports Server (NTRS)

A ladar (laser radar) sensor designed around a pulsed passively Q-switched CO2 laser, capable of a efficient and rapid scans with a narrow beam over a wide field of view, is considered for surveillance and tracking applications in space. The output is a train of narrow pulses with a controllable pulse repetition rate. A resonant vibrating mirror in back of a classical Gregorian telescope, and a plane pointing mirror in front for beam steering, are used in scanning. Scan pulse sequences are described and illustrated. The 10.6 micron ladar set is under consideration as baseline sensor for various space rendezvous and docking applications.

Levinson, S.; Adelman, S.; Lowrey, D. O.

1975-01-01

217

Designed amyloid fibers as materials for selective carbon dioxide capture  

PubMed Central

New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via carbamate formation. Thermodynamic and kinetic capture-and-release tests show the carbamate formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture.

Li, Dan; Furukawa, Hiroyasu; Deng, Hexiang; Liu, Cong; Yaghi, Omar M.; Eisenberg, David S.

2014-01-01

218

Global deforestation: contribution to atmospheric carbon dioxide  

Microsoft Academic Search

A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1960 and 1980 was between 135 X 10¹⁵ and 228 X 10¹⁵ grams. Between 1.8 X 10¹⁵ and 4.7 X 10¹⁵ grams of carbon were released in 1980, of which nearly

G. M. Woodwell; J. E. Hobbie; R. A. Houghton; J. M. Melillo; B. Moore; B. J. Peterson; G. R. Shaver

1983-01-01

219

BRIEF COMMUNICATIONS: Pulsed transverse-discharge carbon dioxide laser without an active-mixture replenishment system (sealed regime)  

Microsoft Academic Search

A description is given of a pulsed TEA CO2 laser having no system for replenishing the active mixture. Prolonged operation in the sealed regime (more than 500 h) was achieved by lowering the pressure of the active mixture, the volume discharge then being considerably more stable, with respect to the oxygen formed by dissociation, than at atmospheric pressure. The small

V. S. Aleinikov; Yu F. Bondarenko; V. N. Volkov; V. V. Zubov; G. S. Starikova; V. K. Sysoev

1981-01-01

220

THE RESPIRATORY RESPONSE TO CARBON DIOXIDE  

PubMed Central

1. A technique for determining the respiratory response to carbon dioxide on the Peabody principle is described. 2. The relation between minute volume of total pulmonary ventilation and percentage of carbon dioxide in the inspired air can be expressed by a simple mathematical formula, viz. Y = K + abz, in which Y is the ventilation rate, X is the CO2 content of the inspired air, and K, a, and b are constants characteristic for the individual. 3. The respiratory response to carbon dioxide as expressed by the total pulmonary ventilation is slightly greater at high oxygen percentages (90 per cent ) than at normal oxygen percentages in the inspired air. 4. Respiratory fatigue may consist of two elementsone nervous, manifesting itself in increased excitability of the center and a more marked response when the demand for pulmonary ventilation is small, the other muscular and involving an inability to respond when the demand for pulmonary ventilation is great.

Davies, H. Whitridge; Brow, George R.; Binger, Carl A. L.

1925-01-01

221

Polymers for metal extractions in carbon dioxide  

DOEpatents

A composition useful for the extraction of metals and metalloids comprises (a) carbon dioxide fluid (preferably liquid or supercritical carbon dioxide); and (b) a polymer in the carbon dioxide, the polymer having bound thereto a ligand that binds the metal or metalloid; with the ligand bound to the polymer at a plurality of locations along the chain length thereof (i.e., a plurality of ligands are bound at a plurality of locations along the chain length of the polymer). The polymer is preferably a copolymer, and the polymer is preferably a fluoropolymer such as a fluoroacrylate polymer. The extraction method comprises the steps of contacting a first composition containing a metal or metalloid to be extracted with a second composition, the second composition being as described above; and then extracting the metal or metalloid from the first composition into the second composition.

DeSimone, Joseph M. (7315 Crescent Ridge Dr., Chapel Hill, NC 27516); Tumas, William (1130 Big Rock Loop, Los Alamos, NM 87544); Powell, Kimberly R. (103 Timber Hollow Ct. Apartment 323, Chapel Hill, NC 27514); McCleskey, T. Mark (1930 Camino Mora, Los Alamos, NM 87544); Romack, Timothy J. (5810 Forest Ridge Dr., Durham, NC 27713); McClain, James B. (8530 Sommersweet La., Raleigh, NC 27612); Birnbaum, Eva R. (1930 Camino Mora, Los Alamos, NM 87544)

2001-01-01

222

Progress in Measurement of Carbon Dioxide Using a Broadband Lidar  

NASA Technical Reports Server (NTRS)

In order to better understand the budget of carbon dioxide in the Earth's atmosphere it is necessary to develop a global high precision understanding of the carbon dioxide column. In order to uncover the 'missing sink" that is responsible for the large discrepancies in the budget as we presently understand it calculation has indicated that measurement accuracy on the order of 1 ppm is necessary. Because typical column average CO2 has now reached 380 ppm this represents a precision on the order of .25% for these column measurements. No species has ever been measured from space at such a precision. In recognition of the importance of understanding the CO2 budget in order to evaluate its impact on global warming the National Research Council in its decadal survey report to NASA recommended planning for a laser based total CO2 mapping mission in the near future. The extreme measurement accuracy requirements on this mission places very strong requirements on the laser system used for the measurement. This work presents an overview of the characteristics necessary in a laser system used to make this measurement. Consideration is given to the temperature dependence, pressure broadening, and pressure shift of the CO2 lines themselves and how these impact the laser system characteristics We have been examining the possibility of making precise measurements of atmospheric carbon dioxide using broad band source of radiation. This means that many of the difficulties in wavelength control can be treated in the detector portion of the system rather than the laser source. It also greatly reduces the number of individual lasers required to make a measurement. Simplifications such as these are extremely desirable for systems designed to operate from space.

Heaps, William S.

2010-01-01

223

Global deforestation: contribution to atmospheric carbon dioxide  

SciTech Connect

A study of effects of terrestrial biota on the amount of carbon dioxide in the atmosphere suggests that the global net release of carbon due to forest clearing between 1960 and 1980 was between 135 X 10/sup 15/ and 228 X 10/sup 15/ grams. Between 1.8 X 10/sup 15/ and 4.7 X 10/sup 15/ grams of carbon were released in 1980, of which nearly 80 percent was due to deforestation, principally in the tropics. The annual release of carbon from the biota and soils exceeded the release from fossil fuels until about 1960. Because the biotic release has been and remains much larger than is commonly assumed, the airborne fraction, usually considered to be about 50 percent of the releases from fossil fuels, was probably between 22 and 43 percent of the total carbon released in 1980. The increase in carbon dioxide in the atmosphere is thought by some to be increasing the storage of carbon in the earth's remaining forests sufficiently to offset the release from deforestation. The interpretation of the evidence presented here suggests no such effect; deforestation appears to be the dominant biotic effect on atmospheric carbon dioxide. If deforestation increases in proportion to population, the biotic release of carbon will reach 9 X 10/sup 15/ grams per year before forests are exhausted early in the next century. The possibilities for limiting the accumulation of carbon dioxide in the atmosphere through reduction in use of fossil fuels and through management of forests may be greater than is commonly assumed.

Woodwell, G.M.; Hobbie, J.E.; Houghton, R.A.; Melillo, J.M.; Moore, B.; Peterson, B.J.; Shaver, G.R.

1983-12-09

224

Scarring of lupus miliaris disseminatus faciei: treatment with a combination of trichloroacetic acid and carbon dioxide laser.  

PubMed

We present a case of a 35-year-old man having a 12-month history of multiple reddish-brown papules on the chin, forehead, cheeks, and eyelids. Histopathologic findings revealed epithelioid cell granulomas with central necrosis consistent with a diagnosis of lupus miliaris disseminatus faciei. After 9 months of combined treatment with ethambutol, rifampin, and pyrazinamide, most lesions gradually resolved but remained as severe disfiguring scars. After 10 sessions of treatments with 100% trichloroacetic acid and CO2 laser, the lupus miliaris disseminatus faciei scars have been much improved and the patient has never experienced a recurrence of disease during subsequent years of follow-up. PMID:24283357

Kang, Boo Kyoung; Shin, Min Kyung

2014-05-01

225

Treatment of vocal fold scar by carbon dioxide laser and collagen injection: retrospective study on 12 patients.  

PubMed

Vocal fold scars are the result of injury to the vocal fold lamina propria. This condition leads to an impaired vibration and usually to poor voice quality. The purpose of our study was to compare the pre- and posttreatment voice assessment scores in patients treated by CO(2) laser-assisted freeing of the scar followed by collagen injection. A group of 12 patients (10 women and 2 men) with vocal fold scars was studied retrospectively. Voice assessment was based on stroboscopy and on perceptual scores using the Grade (G) of the GRABS scale, subjective evaluation by the use of the Voice Handicap Index (VHI), aerodynamic measurements [maximum phonation time (MPT) and phonation quotient (PQ)], and acoustical measurements (frequency range and low intensity). Stroboscopy showed an improvement on the mucosal vocal fold wave and on the glottic competence. The mean VHI was improved from 63.16 to 45.5; G from 2 to 1.41; MPT from 7.05 to 8.62 s; and PQ from 463.02 to 358.54 ml/s. CO(2) laser freeing of vocal fold scars followed by collagen injection, combined with speech therapy, improved significantly the aerodynamic parameters (efficiency of voice), but not the acoustical scores. PMID:20306066

Martnez Arias, Angels; Remacle, Marc; Lawson, Georges

2010-09-01

226

Carbon Dioxide Removal System of the Regenerable Solid Adsorbent Type.  

National Technical Information Service (NTIS)

The development of a regenerable carbon dioxide removal system is discussed. The system utilizes solid zeolites to adsorb carbon dioxide and silica gel for predrying the gas stream. The system is completely regenerable, operates automatically and continuo...

G. A. Remus P. P. Nuccio R. J. Honegger

1969-01-01

227

International Space Station Carbon Dioxide Removal Assembly Testing  

NASA Technical Reports Server (NTRS)

Performance testing of the International Space Station Carbon Dioxide Removal Assembly flight hardware in the United States Laboratory during 1999 is described. The CDRA exceeded carbon dioxide performance specifications and operated flawlessly. Data from this test is presented.

Knox, James C.

2000-01-01

228

46 CFR 169.565 - Fixed carbon dioxide system.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Fixed carbon dioxide system. 169.565 Section 169.565 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...and Firefighting Equipment Firefighting Equipment § 169.565 Fixed carbon dioxide system. (a)...

2013-10-01

229

Organic syntheses employing supercritical carbon dioxide as a reaction solvent  

NASA Technical Reports Server (NTRS)

Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

1993-01-01

230

Organic syntheses employing supercritical carbon dioxide as a reaction solvent  

NASA Technical Reports Server (NTRS)

Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

1991-01-01

231

Continuous measurements of nitrous oxide, carbon monoxide, methane and carbon dioxide in the surface ocean with novel laser-absorption analysers  

NASA Astrophysics Data System (ADS)

In recent years, improvements in spectroscopic technology have revolutionised atmospheric trace gas research. In particular, cavity-based optical absorption analysers allow determination of gas concentrations with high frequency, repeatability, reproducibility and long-term stability. These qualities make them particularly suitable for autonomous measurements on voluntary observing ships (VOS). Here, we present results from three of the first deployments of such analysers on research ships, as a first step towards VOS installations. Los Gatos off-axis ICOS (Integrated Cavity Output Spectroscopy) analysers were used to measure nitrous oxide (N2O), carbon monoxide (CO), methane (CH4) and carbon dioxide (CO2) mixing ratios in ocean surface water during research cruises in 2010, 2011 and 2012. The analysers were coupled to an equilibrator fed by the scientific seawater supply in the ship's laboratories. The equilibrator measurements were alternated with regular measurements of marine air and calibrated standard gases. Short-term precision for 10 s-average N2O mole fractions at an acquisition rate of 1 Hz was better than 0.2 nmol mol-1. The same value was achieved for duplicate measurements of a standard gas analysed within 1 hour of each other. The response time to concentration changes in water was 142-203 s, depending on the headspace flow rate. During the first deployment on the AMT20 cruise (Atlantic Meridional Transect, Southampton to Punta Arenas, 12 October to 25 November 2010), we unexpectedly found the subtropical gyres to be slightly undersaturated in N2O, implying that this region acted as a sink for this greenhouse gas. In contrast, the equatorial region was supersaturated and a source of nitrous oxide to the atmosphere. Mean sea-to-air fluxes were overall small and ranged between -1.6 and 0.11 ?mol m-2 d-1 (negative fluxes imply an net uptake by the ocean). Despite the good short-term repeatability, significant calibration drift occurred between the six-hourly calibration intervals. We have therefore repeated the observations during the AMT22 cruise (Southampton to Punta Arenas, 10 October to 24 November 2012) and will present the results together with the 2010 data. The second deployment during the D366 Round Britain ocean acidification cruise (6 June to 9 July 2011) showed virtually no day-to-day drift, based on the calibration gases and marine air analyses. Preliminary analyses of the data show that CH4 and N2O were supersaturated in the Skagerrak region, presumably due to the influence of Baltic Sea water, and in coastal areas. Phytoplankton blooms show evidence of CO2 draw-down. CO is extremely supersaturated (up to 50 times), which can be attributed to photochemical breakdown of dissolved organic carbon compounds. For the more recent deployments, a CO2/CH4 and an N2O/CO analyser were successfully operated in series, off of a single equilibrator feed. No leaks or other problems occurred during these deployments, which shows that such a configuration would be ideal for VOS installations as part of the ICOS observational network.

Kaiser, Jan; Grefe, Imke; Wager, Natalie; Bakker, Dorothee C. E.; Lee, Gareth A.

2013-04-01

232

U.S. Energy-Related Carbon Dioxide Emissions  

EIA Publications

U.S. Energy Information Administration releases its online analysis of 2012 energy-related carbon dioxide emissions today. It indicates U.S. carbon dioxide emissions from the consumption of fossil fuels were 5,290 million metric tons carbon dioxide in 2012, a decrease of almost 4% from the 2011 level. Energy-related carbon dioxide emissions have declined in five of the last seven years and are the lowest they have been since 1994.

2013-10-21

233

Carbon Dioxide Research Conference: Carbon Dioxide, Science and Consensus.  

National Technical Information Service (NTIS)

The DOE program focuses on three areas each of which requires more research before the many CO sub 2 -related questions can be answered. These areas include the global carbon cycle, climate effects, and vegetation effects. Additional information is needed...

1983-01-01

234

Methanation of carbon dioxide: an overview  

Microsoft Academic Search

Although being very challenging, utilization of carbon dioxide (CO2) originating from production processes and flue gases of CO2-intensive sectors has a great environmental and industrial potential due to improving the resource efficiency of industry\\u000a as well as by contributing to the reduction of CO2 emissions. As a renewable and environmentally friendly source of carbon, catalytic approaches for CO2 fixation in

Wang Wei; Gong Jinlong

2011-01-01

235

Platinum catalyst for forming carbon dioxide  

SciTech Connect

This patent describes an improvement in a platinum wire catalytic apparatus for catalyzing the reaction of carbon monoxide and oxygen to form carbon dioxide by directly heating the catalyst to an activation temperature of about 1000{degrees} C. The improvement comprises a layer of platinum black deposited on the surface of the platinum wire to form a coating whereby the wire with the coating is directly heated to an activation temperature within the range of about 150 to 300{degrees} C.

McNeil, J.A.; Cohn, D.B.

1991-05-28

236

A Simple Model for Atmospheric Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will create and use a differential equation of rate-of-change of atmospheric carbon dioxide. They will refer to the "Keeling Curve" graph and information on the sources and sinks of carbon on Earth to create the equation and apply it to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

237

Ocean uptake of carbon dioxide  

Microsoft Academic Search

Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these

Tsung-Hung Peng; Taro Takahashi

1993-01-01

238

Ocean uptake of carbon dioxide  

Microsoft Academic Search

Factors controlling the capacity of the ocean for taking up anthropogenic C0² include carbon chemistry, distribution of alkalinity, pCO² and total concentration of dissolved C0², sea-air pCO² difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and

Tsung-Hung Peng; Taro Takahashi

1993-01-01

239

Carbon dioxide hydrationand dehydration kinetics in seawater  

Microsoft Academic Search

Rate constants for the hydration and dehydration reactions of carbon dioxide with water and with hydroxyl ion were measured in seawater by a pH-stat method at salinities (X lO:l) from 3.4 to 37.06 at 25C and from 5\\

Kenneth S. Johnson

1982-01-01

240

Carbon dioxide embolism during endoscopic vein harvesting.  

PubMed

Endoscopic vein harvesting (EVH) is becoming common for the patients undergoing coronary artery bypass grafting. Using carbon dioxide insufflations during the vein harvest can produce rare but catastrophic CO(2) embolism. We report a case of massive right atrial CO(2) embolism due to femoral vein injury which occurred during the performance of a routine EVH procedure. PMID:18381362

Tamim, Muhammed; Omrani, Maher; Tash, Adel; El Watidy, Ahmed

2008-08-01

241

Ocean Acidification: The Other Carbon Dioxide Problem  

NSDL National Science Digital Library

This NOAA video discusses how the ocean absorbs the increased amount of carbon dioxide released into the atmosphere, thereby changing the pH and buffering action of the ocean. These changes in pH are impacting calcifying organisms, such as corals and shellfish, and related food chains and ecosystems.

Noaa; Administration, National O.

242

Geothermal carbon dioxide for use in greenhouses  

Microsoft Academic Search

Geothermal fluids often contain carbon dioxide, which is a very effective growth stimulant for plants in greenhouses. Studies have shown that as CO concentration is increased from a normal level of 300 ppm (mmol\\/kmol) to levels of approximately 1000 ppm crop yields may increase by up to 15% (Ullmann`s Encyclopedia of Industrial Chemistry, 1989). It is suggested that geothermal greenhouse

M. G. Dunstall; G. Graeber

1997-01-01

243

World Electricity Consumption and Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will analyze a table of global electricity consumption to answer a series of questions and consider the production of carbon dioxide associated with that consumption. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

244

Acid sorption regeneration process using carbon dioxide  

DOEpatents

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Husson, Scott M. (Anderson, SC)

2001-01-01

245

Nitrile oxide cycloadditions in supercritical carbon dioxide.  

PubMed

The regioselectivity of dipolar cycloadditions of mesitonitrile oxide to various dipolarophiles in supercritical carbon dioxide can be tuned by changes in density, the magnesium bromide-mediated cycloaddition to pent-1-en-3-ol proceeding with higher stereoselectivity than in most conventional solvents. PMID:15543310

Lee, Connie K Y; Holmes, Andrew B; Al-Duri, Bushra; Leeke, Gary A; Santos, Regina C D; Seville, Jonathan P K

2004-11-21

246

Recent Events: a Perspective on Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will compare the carbon dioxide produced as a result of two 2010 events: the eruption of the Eyjafjalla Volcano and the burning of oil on the ocean surface to address the Gulf of Mexico oil spill. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

247

DIETHANOLAMINE-CARBON DIOXIDE BUFFER PRODUCES ETHYLENE  

EPA Science Inventory

Carbon dioxide concentrates in containers are frequently controlled by using a diethanolamine-bicarbonate buffer. Current studies show that this buffer produces ethylene and that the production increases with increasing pH and/or time in the incubation vessel. Ethylene is not pro...

248

Spectroscopic carbon dioxide sensor for automotive applications  

Microsoft Academic Search

In this paper, we present the first spectroscopic carbon dioxide sensor designed for automotive applications. The sensor is based on the well known infrared measurement principle. It includes a new robust infrared gas-detector and a corresponding, newly developed, ASIC. First application studies show its suitability for automatic vehicle ventilation systems and for leak detection in R744 air conditioning systems.

Michael Arndt; Maximilian Sauer

2004-01-01

249

27 CFR 26.222 - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...false Still wines containing carbon dioxide. 26.222 Section...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...222 Still wines containing carbon dioxide. (a) General...not more than 0.392 gram of carbon dioxide per 100...

2010-04-01

250

27 CFR 26.222 - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...false Still wines containing carbon dioxide. 26.222 Section...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...222 Still wines containing carbon dioxide. (a) General...not more than 0.392 gram of carbon dioxide per 100...

2009-04-01

251

27 CFR 26.52 - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...false Still wines containing carbon dioxide. 26.52 Section...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...52 Still wines containing carbon dioxide. (a) General...not more than 0.392 gram of carbon dioxide per 100...

2010-04-01

252

27 CFR 26.52 - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...false Still wines containing carbon dioxide. 26.52 Section...Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT...52 Still wines containing carbon dioxide. (a) General...not more than 0.392 gram of carbon dioxide per 100...

2009-04-01

253

Effect of Carbon Dioxide on Multiplication of Fusarium in Soil  

Microsoft Academic Search

NUMEROUS studies have been made on the effects of carbon dioxide on fungal growth in pure culture, and on substrates other than soil. Since soil is the natural habitat of many fungi, and frequently has carbon dioxide-levels exceeding that present in normal air, it is important that effects of carbon dioxide-enriched air on fungal behaviour in soil be investigated. With

R. H. Stover; S. R. Freiberg

1958-01-01

254

Absorption of carbon dioxide in waste tanks (October 21, 1986).  

National Technical Information Service (NTIS)

The absorption of atmospheric carbon dioxide in eight waste tanks located in H-Area has been monitored for a period of six months. All of the tanks are continuously absorbing carbon dioxide. Approximately 75% of the carbon dioxide entering the waste tanks...

D. T. Hobbs

1986-01-01

255

49 CFR 173.217 - Carbon dioxide, solid (dry ice).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section...Than Class 1 and Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered...

2010-10-01

256

49 CFR 173.217 - Carbon dioxide, solid (dry ice).  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Carbon dioxide, solid (dry ice). 173.217 Section...Than Class 1 and Class 7 § 173.217 Carbon dioxide, solid (dry ice). (a) Carbon dioxide, solid (dry ice), when offered...

2009-10-01

257

Estimated Carbon Dioxide Emissions in 2008: United States  

Microsoft Academic Search

Flow charts depicting carbon dioxide emissions in the United States have been constructed from publicly available data and estimates of state-level energy use patterns. Approximately 5,800 million metric tons of carbon dioxide were emitted throughout the United States for use in power production, residential, commercial, industrial, and transportation applications in 2008. Carbon dioxide is emitted from the use of three

C A Smith; A J Simon; R D Belles

2011-01-01

258

Catalyst cartridge for carbon dioxide reduction unit  

NASA Technical Reports Server (NTRS)

A catalyst cartridge, for use in a carbon dioxide reducing apparatus in a life support system for space vehicles, is described. The catalyst cartridge includes an inner perforated metal wall, an outer perforated wall space outwardly from the inner wall, a base plate closing one end of the cartridge, and a cover plate closing the other end of the cartridge. The cover plate has a central aperture through which a supply line with a heater feeds a gaseous reaction mixture comprising hydrogen and carbon dioxide at a temperature from about 1000 to about 1400 F. The outer surfaces of the internal wall and the inner surfaces of the outer wall are lined with a ceramic fiber batting material of sufficient thickness to prevent carbon formed in the reaction from passing through it. The portion of the surfaces of the base and cover plates defined within the inner and outer walls are also lined with ceramic batting. The heated reaction mixture passes outwardly through the inner perforated wall and ceramic batting and over the catalyst. The solid carbon product formes is retained within the enclosure containing the catalyst. The solid carbon product formed is retained within the enclosure containing the catalyst. The water vapor and unreacted carbon dioxide and any intermediate products pass through the perforations of the outer wall.

Holmes, R. F. (inventor)

1973-01-01

259

HIGH PRESSURE VAPOR LIQUID EQUILIBRIUM FOR CARBON DIOXIDE + ETHANOL + 2BUTANONE SYSTEM  

Microsoft Academic Search

Vapor-liquid equilibrium was measured for three binary systems, carbon dioxide + ethanol, carbon dioxide + 2-butanone, and ethanol + 2-butanone, and a ternary system, carbon dioxide + ethanol + 2-butanone, at 313.2K. A circulation type apparatus was used in case of the high pressure systems, carbon dioxide + ethanol, carbon dioxide + 2-butanone, and carbon dioxide + ethanol + 2-butanone,

Tomoya TSUJI; Masatoshi SAKAI; Toshihiko HIAKI

260

Carbon Dioxide Snow Storms During the Polar Night on Mars  

NASA Technical Reports Server (NTRS)

The Mars Orbiter Laser Altimeter (MOLA) detected clouds associated with topographic features during the polar night on Mars. While uplift generated from flow over mountains initiates clouds on both Earth and Mars, we suggest that the Martian clouds differ greatly from terrestrial mountain wave clouds. Terrestrial wave clouds are generally compact features with sharp edges due to the relatively small particles in them. However, we find that the large mass of condensible carbon dioxide on Mars leads to clouds with snow tails that may extend many kilometers down wind from the mountain and even reach the surface. Both the observations and the simulations suggest substantial carbon dioxide snow precipitation in association with the underlying topography. This precipitation deposits CO2, dust and water ice to the polar caps, and may lead to propagating geologic features in the Martian polar regions.

Toon, Owen B.; Colaprete, Anthony

2001-01-01

261

Ocean uptake of carbon dioxide  

SciTech Connect

Factors controlling the capacity of the ocean for taking up anthropogenic C0{sup 2} include carbon chemistry, distribution of alkalinity, pCO{sup 2} and total concentration of dissolved C0{sup 2}, sea-air pCO{sup 2} difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0{sup 2} uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0{sup 2} from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0{sup 2} fertilization is a potential candidate for such missing carbon sinks.

Peng, Tsung-Hung [Oak Ridge National Lab., TN (United States); Takahashi, Taro [Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory

1993-06-01

262

Ocean uptake of carbon dioxide  

SciTech Connect

Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0[sup 2] uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0[sup 2] from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0[sup 2] fertilization is a potential candidate for such missing carbon sinks.

Peng, Tsung-Hung (Oak Ridge National Lab., TN (United States)); Takahashi, Taro (Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory)

1993-01-01

263

Carbon dioxide detection using a co-doped Tm-Ho optical fiber  

NASA Astrophysics Data System (ADS)

A Tm-Ho co-doped optical fiber laser exhibits significant fluorescence between 1.6 and 2.1 micrometers . Such a fiber can from the basis of a gas detection system, since many gases of interest have overtone absorption bands in this wavelength region: in particular, carbon dioxide, methane, arsine, replacement gases for refrigerants, and nitrous oxide. Using this fiber we have demonstrated a simple shceme for the detection of overtone absorption bands of carbon dioxide in the 2 micrometers region. The detection sensitivity for carbon dioxide with this present method is of the order of 1%.

Morse, Theodore F.; Oh, Kyunghwan; Reinhart, Lawrence J.

1995-09-01

264

Testing of a Two-Micron Lidar System for Carbon Dioxide Profiling in the Atmosphere  

Microsoft Academic Search

Utilizing a tunable two-micron pulse laser transmitter, a two-micron lidar system has been developed at NASA Langley Research Center (LaRC) for profiling atmospheric carbon dioxide. Owing to the unavailability of conventional detectors that meet the carbon dioxide measurement requirements at this wavelength, this system employs an advanced two-micron heterojunction phototransistor (HPT) at the receiver end. This application of HPT in

T. F. Refaat; S. Ismail; G. J. Koch; M. Rubio; T. L. Mack; A. Notari; J. E. Collins; J. Lewis; R. J. Deyoung; Y. Choi; N. Abedin; U. N. Singh

2009-01-01

265

Carbon Dioxide: Production and Sequestration  

NSDL National Science Digital Library

In this problem set, learners will refer to a satellite image to calculate the rate of carbon sequestration in the areas of bare land and forested lawn shown to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

266

Ocean uptake of carbon dioxide.  

National Technical Information Service (NTIS)

Factors controlling the capacity of the ocean for taking up anthropogenic CO(sup 2) include carbon chemistry, distribution of alkalinity, pCO(sup 2) and total concentration of dissolved CO(sup 2), sea-air pCO(sup 2) difference, gas exchange rate across th...

T. H. Peng T. Takahashi

1993-01-01

267

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

SciTech Connect

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.

O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

2000-01-01

268

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

Microsoft Academic Search

Sodium based sorbents including sodium carbonate may be used to capture carbon dioxide from flue gas. A relatively concentrated carbon dioxide stream may be recoverable for sequestration when the sorbent is regenerated. Electrobalance tests indicated that sodium carbonate monohydrate was formed in a mixture of helium and water vapor at temperatures below 65 C. Additional compounds may also form, but

David A. Green; Brian S. Turk; Raghubir P. Gupta; Alejandro Lopez-Ortiz; Douglas P. Harrison; Ya Liang

2001-01-01

269

Climate impact of increasing atmospheric carbon dioxide  

SciTech Connect

The global temperature rose by 0.2/sup 0/C between the middle 1960's and 1980, yielding a warming of 0.4/sup 0/C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980's. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.

Hansen, J.; Johnson, D.; Lacis, A.; Lebedeff, S.; Lee, P.; Rind, D.; Russell, G.

1981-08-28

270

Climate Impact of Increasing Atmospheric Carbon Dioxide  

NASA Astrophysics Data System (ADS)

The global temperature rose by 0.2 degrees C between the middle 1960's and 1980, yielding a warming of 0.4 degrees C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980's. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.

Hansen, J.; Johnson, D.; Lacis, A.; Lebedeff, S.; Lee, P.; Rind, D.; Russell, G.

1981-08-01

271

Climate Impact of Increasing Atmospheric Carbon Dioxide  

Microsoft Academic Search

The global temperature rose by 0.2 degrees C between the middle 1960's and 1980, yielding a warming of 0.4 degrees C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about

J. Hansen; D. Johnson; A. Lacis; S. Lebedeff; P. Lee; D. Rind; G. Russell

1981-01-01

272

Solubilities of phenols in supercritical carbon dioxide  

SciTech Connect

Equilibrium solubilities of pure anthracene at 50 C, 1-naphthol at 35, 45, and 55 C, and hydroquinone at 35 and 45 C in supercritical carbon dioxide over a pressure range of about 85--300 bar have been measured using a supercritical fluid extractor coupled with an external high-pressure liquid chromatographer. The solubility results, along with those for other phenols reported in the literature, are correlated with the translated-modified Peng Robinson equation of state.

Coutsikos, P.; Magoulas, K.; Tassios, D. [National Technical Univ. of Athens (Greece)

1995-07-01

273

Carbon dioxide capture with concentrated, aqueous piperazine  

Microsoft Academic Search

Concentrated, aqueous piperazine (PZ) has been investigated as a novel amine solvent for carbon dioxide (CO2) absorption. The CO2 absorption rate of aqueous PZ is more than double that of 7m MEA and the amine volatility at 40C ranges from 11 to 21ppm. Thermal degradation is negligible in concentrated, aqueous PZ up to a temperature of 150C, a significant advantage

Stephanie A. Freeman; Ross Dugas; David H. Van Wagener; Thu Nguyen; Gary T. Rochelle

2010-01-01

274

Improved immobilized carbon dioxide capture sorbents  

Microsoft Academic Search

The capture of carbon dioxide from simulated flue gas streams has been achieved by using immobilized and aminated-SBA-15 solid sorbents. SBA-15, a mesoporous silica material with a uniform pore size of 21 nm and a surface area of 200?230 m2\\/g. The solid sorbents prepared in this study exhibit similar or improved capacities relative to those already used to control CO2

M. L. Gray; Y. Soong; K. J. Champagne; H. Pennline; J. P. Baltrus; R. W. Stevens Jr.; R. Khatri; S. S. C. Chuang; T. Filburn

2005-01-01

275

Polymerizations in Liquid and Supercritical Carbon Dioxide  

Microsoft Academic Search

In the past few years, remarkable progress has been made in defining the scope and limitations of carbon dioxide (CO2) as an inert polymerization medium. It has appear that CO2 represents a viable solvent choice for a variety of propagation mechanisms including both chain growth and step growth polymerizations.\\u000a When the environmental advantages of CO2 are combined with its ability

Dorian A. Canelas; Joseph M. DeSimone

276

Transport of Carbon Dioxide and Radioactive Waste  

Microsoft Academic Search

\\u000a A comparative assessment of carbon dioxide (CO2) and radioactive waste transport systems associated with electricity generation was undertaken on the basis of 15 criteria\\u000a grouped under three areas, namely the transport chain, policy aspects and state of the technology. For CO2, we considered exclusively the transport that would take place under a future large-scale capture and storage infrastructure.\\u000a Our study

Daro R. Gmez; Michael Tyacke

277

A weekly cycle in atmospheric carbon dioxide  

Microsoft Academic Search

We present a new statistic called the Mean Symmetrized Residual (MSR) for detection and quantification of a weekly cycle in measured daily atmospheric carbon dioxide (CO2). At the Mauna Loa Observatory in Hawaii, we conclude that CO2 concentrations, on average, are significantly lower (0.022 parts per million by volume, ppmv) on weekends (SaturdaySunday) than during the rest of the week.

Randall S. Cerveny; Kevin J. Coakley

2002-01-01

278

Bench-to-bedside review: Carbon dioxide  

PubMed Central

Carbon dioxide is a waste product of aerobic cellular respiration in all aerobic life forms. PaCO2 represents the balance between the carbon dioxide produced and that eliminated. Hypocapnia remains a common - and generally underappreciated - component of many disease states, including early asthma, high-altitude pulmonary edema, and acute lung injury. Induction of hypocapnia remains a common, if controversial, practice in both adults and children with acute brain injury. In contrast, hypercapnia has traditionally been avoided in order to keep parameters normal. More recently, advances in our understanding of the role of excessive tidal volume has prompted clinicians to use ventilation strategies that result in hypercapnia. Consequently, hypercapnia has become increasingly prevalent in the critically ill patient. Hypercapnia may play a beneficial role in the pathogenesis of inflammation and tissue injury, but may hinder the host response to sepsis and reduce repair. In contrast, hypocapnia may be a pathogenic entity in the setting of critical illness. The present paper reviews the current clinical status of low and high PaCO2 in the critically ill patient, discusses the insights gained to date from studies of carbon dioxide, identifies key concerns regarding hypocapnia and hypercapnia, and considers the potential clinical implications for the management of patients with acute lung injury.

2010-01-01

279

Carbon dioxide embolism during laparoscopic sleeve gastrectomy  

PubMed Central

Bariatric restrictive and malabsorptive operations are being carried out in most countries laparoscopically. Carbon dioxide or gas embolism has never been reported in obese patients undergoing bariatric surgery. We report a case of carbon dioxide embolism during laparoscopic sleeve gastrectomy (LSG) in a young super obese female patient. Early diagnosis and successful management of this complication are discussed. An 18-year-old super obese female patient with enlarged fatty liver underwent LSG under general anesthesia. During initial intra-peritoneal insufflation with CO2 at high flows through upper left quadrant of the abdomen, she had precipitous fall of end-tidal CO2 and SaO2 % accompanied with tachycardia. Early suspicion led to stoppage of further insufflation. Clinical parameters were stabilized after almost 30 min, while the blood gas analysis was restored to normal levels after 1 h. The area of gas entrainment on the damaged liver was recognized by the surgeon and sealed and the surgery was successfully carried out uneventfully. Like any other laparoscopic surgery, carbon dioxide embolism can occur during bariatric laparoscopic surgery also. Caution should be exercised when Veress needle is inserted through upper left quadrant of the abdomen in patients with enlarged liver. A high degree of suspicion and prompt collaboration between the surgeon and anesthetist can lead to complete recovery from this potentially fatal complication.

Zikry, Amir Abu; DeSousa, Kalindi; Alanezi, Khaled H

2011-01-01

280

Carbon dioxide in Arctic and subarctic regions  

SciTech Connect

A three year research project was presented that would define the role of the Arctic ocean, sea ice, tundra, taiga, high latitude ponds and lakes and polar anthropogenic activity on the carbon dioxide content of the atmosphere. Due to the large physical and geographical differences between the two polar regions, a comparison of CO/sub 2/ source and sink strengths of the two areas was proposed. Research opportunities during the first year, particularly those aboard the Swedish icebreaker, YMER, provided additional confirmatory data about the natural source and sink strengths for carbon dioxide in the Arctic regions. As a result, the hypothesis that these natural sources and sinks are strong enough to significantly affect global atmospheric carbon dioxide levels is considerably strengthened. Based on the available data we calculate that the whole Arctic region is a net annual sink for about 1.1 x 10/sup 15/ g of CO/sub 2/, or the equivalent of about 5% of the annual anthropogenic input into the atmosphere. For the second year of this research effort, research on the seasonal sources and sinks of CO/sub 2/ in the Arctic will be continued. Particular attention will be paid to the seasonal sea ice zones during the freeze and thaw periods, and the tundra-taiga regions, also during the freeze and thaw periods.

Gosink, T.A.; Kelley, J.J.

1981-03-01

281

Carbon dioxide makes heat therapy work  

SciTech Connect

Scientists can now propagate healthy blueberry and raspberry plants from virus-infected stock by treating it with heat and carbon dioxide. Plants are grown at 100/sup 0/F, which makes them develop faster than the virus can spread. Then cuttings are taken of the new growth - less than an inch long - and grown into full-sized, virus-free plants. But in this race to outdistance the virus, some plant species are not able to take the heat. Some even die. Chemical reactions double for every 14/sup 0/F rise in temperature. So, if you try to grow a plant at 100/sup 0/F that was originally growing at 86/sup 0/F, it will double its respiration rate. Adding carbon dioxide increases the rate of photosynthesis in plants, which increases the plant's food reserves. What carbon dioxide does to allow some plants to grow at temperatures at which they would otherwise not survive and it allows other plants to grow for longer periods at 100/sup 0/F. One problem with the process, says Converse, is that the longer plants are exposed to heat the greater the mutation rate. So, resulting clones should be closely examined for trueness to horticultural type.

Sherman, H.

1987-01-01

282

Extraction of furfural with carbon dioxide  

SciTech Connect

A new approach to separate furfural from aqueous waste has been investigated. Recovery of furfural and acetic acid from aqueous effluents of a paper mill has successfully been applied on an industrial scale since 1981. The process is based on the extraction of furfural and acetic acid by the solvent trooctylphosphineoxide (TOPO). Common extraction of both substances may cause the formation of resin residues. Improvement was expected by selective extraction of furfural with chlorinated hydrocarbons, but ecological reasons stopped further development of this project. The current investigation is centered in the evaluation of extraction of furfural by supercritical carbon dioxide. The influence of temperature and pressure on the extraction properties has been worked out. The investigation has considered the multi-component system furfural-acetic acid-water-carbon dioxide. Solubility of furfural in liquid and supercritical carbon dioxide has been measured, and equilibrium data for the ternary system furfural-water-CO{sub 2} as well as for the quaternary system furfural-acetic acid-water-CO{sub 2} have been determined. A high-pressure extraction column has been used for evaluation of mass transfer rates.

Gamse, T.; Marr, R. [Institut fuer Thermische Verfahrenstechnik, Graz (Austria); Froeschl, F.; Siebenhofer, M. [VTU, Graz (Austria)

1997-01-01

283

Carbon dioxide reduction by the Bosch process  

NASA Technical Reports Server (NTRS)

Prototype units for carrying out the reduction of carbon dioxide to elementary carbon have been built and operated successfully. In some cases, however, startup difficulties have been reported. Moreover, the recycle reactor product has been reported to contain only small amounts of water and undesirably high yields of methane. This paper presents the results of the first phase of an experimental study that was carried out to define the mechanisms occurring in the reduction process. Conclusions are drawn and possible modifications to the present recycle process are suggested.

Manning, M. P.; Reid, R. C.

1975-01-01

284

Carbon dioxide capture at the molecular level.  

PubMed

Carbon dioxide is recognized as a typical greenhouse gas and drastic reduction of CO2 emissions from industrial process is becoming more and more important in relation to global warming. In fact, the reaction between monoethanolamine (MEA) and CO2 in aqueous solution has been widely used for the removal from flue gases. In this study, the role of the interplay between solvent water and nitrogen (MEA)-carbon (CO2) bond formation is discussed based on the molecular theory using RISM-SCF-SEDD, which is the hybrid method of quantum chemistry of solute and statistical mechanics of solvent. PMID:19774287

Iida, Kenji; Yokogawa, Daisuke; Ikeda, Atsushi; Sato, Hirofumi; Sakaki, Shigeyoshi

2009-10-14

285

Carbon dioxide sensitivity of zeolitic imidazolate frameworks.  

PubMed

Zeolitic imidazolate frameworks of zinc, cobalt, and cadmium, including the framework ZIF-8 commercially sold as Basolite Z1200, exhibit surprising sensitivity to carbon dioxide under mild conditions. The frameworks chemically react with CO2 in the presence of moisture or liquid water to form carbonates. This effect, which has been previously not reported in metal-organic framework chemistry, provides an explanation for conflicting reports on ZIF-8 stability to water and is of outstanding significance for evaluating the potential applications of metal-organic frameworks, especially for CO2 sequestration. PMID:24889776

Mottillo, Cristina; Fri?i?, Tomislav

2014-07-14

286

Carbon Dioxide Aquariums Greenhouse Gas Lesson  

NSDL National Science Digital Library

This classroom activity looks at carbon dioxide and its role in climate change. Students will perform an in-class experiment using aquariums. CO2 gas will be added to one aquarium, and measurements are taken of both aquariums over a one or two week period. This lesson includes step by step instructions on carrying out the experiment. The unit is a good introduction to the concepts of the carbon cycle, heat transfer, energy flow in ecosystems, the human impact on ecosystems and climate, non-renewable energy, resource consumption and pollution. This document may be downloaded in PDF file format. A class worksheet is included with the document.

Orzali, Joe

2009-01-01

287

Reduction of carbon dioxide on modified glassy carbon electrodes  

SciTech Connect

Carbon dioxide in the atmosphere gives an important contribution to environmental pollution due to the progressive increase of its production everywhere from many sources. It is believed now that the capacity of the biosphere, due to absorption and transformation of CO{sub 2}, has been considerably exceeded and many attempts to overcome this problem by different ways, have been successful. Electrochemical reduction seems to be an appropriate route for carbon dioxide consumption and its transformation to useful compounds. Electrochemical reduction of carbon dioxide on glassy carbon (GC) was studied by applying different potential regimes and monitoring the effect of the electrode surface conditioning, as well as the nature of supporting electrolyte, upon the nature of the reaction. In the case of constant potential electrolyses, a rapid decay of the cathodic current was observed, while application of a suitable pulse program to the working electrode, in addition to the ultrasonic cleaning of the surface, allowed completion of the reaction without premature current downfall. Modification of the electrode surface, by applying potential pulses, caused a decrease of the reduction potential of CO{sub 2} on glassy carbon. High yields in carbon monoxide and methanol were obtained in these media, with the highest value obtained for methanol in sodium chloride and carbon monoxide in ammonium oxalate.

Hernandez, R.M.; Marquez, J.; Marquez, O.P.; Choy, M.; Ovalles, C.; Garcia, J.J.; Scharifker, B.

1999-11-01

288

Atmospheric Carbon Dioxide and Carbon Reservoir Changes  

Microsoft Academic Search

The net release of CO2 from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 109 tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th

Minze Stuiver

1978-01-01

289

Sequestering Naturally Occurring Liquid Carbon Dioxide in the Deep Ocean  

NASA Astrophysics Data System (ADS)

Liquid carbon dioxide has been found as shallow as 1,500 meters in seafloor ooze. Did the liquid carbon dioxide originate from volcanic activity? Or did bacteria convert organic matter, which started as atmospheric carbon dioxide, into methane and liquid carbon dioxide? At typical ocean temperatures carbon dioxide coming out of solution below 600 meters will be liquid. Therefore, one likely mechanism for generating liquid carbon dioxide in seafloor ooze is the bacterial decomposition of organic matter. This paper examines quantitative and qualitative bacterial decomposition of aquatic biomass, with an emphasis on assessing and demonstrating feasibility. Calculations suggest natural processes sequestering liquid carbon dioxide in the seafloor can be sustainably increased to decrease atmospheric carbon dioxide concentrations. First, algae growing on the ocean surface absorb carbon dioxide. The algae are then gathered into a submerged container. Naturally occurring bacteria will digest the algae producing methane, liquid carbon dioxide, and ammonium. The ammonium can be recycled as a nutrient for growing more algae. Bacterial decomposition continues in dilute solutions with any biomass. The process does not require any particular biomass. Also, concentrating the biomass by removing water is not essential. The buoyancy provided by water allows relatively inexpensive tension fabric structures to contain the dilute algae and decomposition products. Calculations based on algae growth in open ponds and experience with bacterial decomposition at 1 to 5 bar pressures suggest the economics of the associated macro-algae growing and harvesting can favor increasing ocean species diversity.

Capron, M. E.

2008-12-01

290

Carbon dioxide solubility and carbon isotope fractionation in basaltic melt  

SciTech Connect

Carbon dioxide solubility and isotope fractionation data for a MORB composition at 1,200-1,400C and 5-20 kbar have been obtained using piston-cylinder apparatus and stepped-heating mass spectrometry. Carbon dioxide solubility in basalt melt at 5, 10 and 20 kbar is 0.15-0.17%, 0.45-0.51%, and 1.49%, respectively. Values for {Delta}Co{sub 2}(vap) - CO 2/3{sup {minus}} (basalt melt), obtained from the difference between the isotopic compositions for coexisting vapor and melt, vary from 1.8% to 2.2%. A review of measured and estimated values for carbon isotope fractionation between CO{sub 2} vapor and carbon dissolved in basic melts shows variation from 1.8% to 4.6%. Results of this study and other considerations favor relatively small equilibrium CO{sub 2} vapor melt fractionation factors around 2%.

Mattey, D.P. (Univ. of London, Egham Hill (United Kingdom) Univ. of Tasmania, Hobart (Australia))

1991-11-01

291

Automated carbon dioxide cleaning system  

NASA Technical Reports Server (NTRS)

Solidified CO2 pellets are an effective blast media for the cleaning of a variety of materials. CO2 is obtained from the waste gas streams generated from other manufacturing processes and therefore does not contribute to the greenhouse effect, depletion of the ozone layer, or the environmental burden of hazardous waste disposal. The system is capable of removing as much as 90 percent of the contamination from a surface in one pass or to a high cleanliness level after multiple passes. Although the system is packaged and designed for manual hand held cleaning processes, the nozzle can easily be attached to the end effector of a robot for automated cleaning of predefined and known geometries. Specific tailoring of cleaning parameters are required to optimize the process for each individual geometry. Using optimum cleaning parameters the CO2 systems were shown to be capable of cleaning to molecular levels below 0.7 mg/sq ft. The systems were effective for removing a variety of contaminants such as lubricating oils, cutting oils, grease, alcohol residue, biological films, and silicone. The system was effective on steel, aluminum, and carbon phenolic substrates.

Hoppe, David T.

1991-01-01

292

Germanium dioxide whiskers synthesized by laser ablation  

NASA Astrophysics Data System (ADS)

We obtained germanium dioxide (GeO2) whiskers in bulk quantity by ablating a germanium target at 820 C with a pulsed KrF excimer laser in an argon atmosphere. Most of the GeO2 whiskers were smooth and straight with hexagonal or triangular, or quadrilateral cross sections while some of them had a bamboo-shoot-shaped form. Results of scanning electron microscopy, transmission electron microscopy, and x-ray diffraction showed that the whiskers are hexagonal crystalline GeO2.

Tang, Y. H.; Zhang, Y. F.; Wang, N.; Bello, I.; Lee, C. S.; Lee, S. T.

1999-06-01

293

Carbon Dioxide Transport through Membranes*  

PubMed Central

Several membrane channels, like aquaporin-1 (AQP1) and the RhAG protein of the rhesus complex, were hypothesized to be of physiological relevance for CO2 transport. However, the underlying assumption that the lipid matrix imposes a significant barrier to CO2 diffusion was never confirmed experimentally. Here we have monitored transmembrane CO2 flux (JCO2) by imposing a CO2 concentration gradient across planar lipid bilayers and detecting the resulting small pH shift in the immediate membrane vicinity. An analytical model, which accounts for the presence of both carbonic anhydrase and buffer molecules, was fitted to the experimental pH profiles using inverse problems techniques. At pH 7.4, the model revealed that JCO2 was entirely rate-limited by near-membrane unstirred layers (USL), which act as diffusional barriers in series with the membrane. Membrane tightening by sphingomyelin and cholesterol did not alter JCO2 confirming that membrane resistance was comparatively small. In contrast, a pH-induced shift of the CO2 hydration-dehydration equilibrium resulted in a relative membrane contribution of about 15% to the total resistance (pH 9.6). Under these conditions, a membrane CO2 permeability (3.2 1.6 cm/s) was estimated. It indicates that cellular CO2 uptake (pH 7.4) is always USL-limited, because the USL size always exceeds 1 ?m. Consequently, facilitation of CO2 transport by AQP1, RhAG, or any other protein is highly unlikely. The conclusion was confirmed by the observation that CO2 permeability of epithelial cell monolayers was always the same whether AQP1 was overexpressed in both the apical and basolateral membranes or not.

Missner, Andreas; Kugler, Philipp; Saparov, Sapar M.; Sommer, Klaus; Mathai, John C.; Zeidel, Mark L.; Pohl, Peter

2008-01-01

294

Carbon dioxide: A substitute for phosgene  

SciTech Connect

One of the many goals of the green chemistry movement is to eliminate the use of phosgene (COCl{sub 2}), an extremely hazardous compound used in many syntheses, including the production of carbamates, organic carbonates, and polymers. One of the most interesting options for eliminating this compound is to replace it with CO{sub 2}. In addition to carbon dioxide`s abundance and benign nature, it has the benefits of recycling carbon and of reducing the amount of CO{sub 2} released into the atmosphere when its use is linked with other processes that emit CO{sub 2}. Several synthetic strategies that do not use phosgene are under development. The authors briefly review the most interesting ones and then expand on the use of CO{sub 2} as a potential building block for organic carbamates, carbonates, and isocyanates. One of these routes, polycarbonate synthesis, is already in industrial-scale operation: PAC Polymers Inc. currently produces CO{sub 2}-epoxide copolymers. The synthesis of carbamates and substituted ureas has been developed, and this process awaits industrial exploitation.

Aresta, M.; Quaranta, E. [Univ. of Bari (Italy)

1997-03-01

295

The nature of carbon dioxide waters in Snaefellsnes, western Iceland  

USGS Publications Warehouse

Over 20 occurrences of thermal and non-thermal waters rich in carbon dioxide are known in the Snaefellsnes Peninsula of western Iceland. On the basis of the thermal, chemical and isotopic characteristics of these waters, and hydrological considerations, it is concluded that they represent meteoric waters which have seeped to variable depths into the bedrock. Ascending carbon dioxide gas originating from intrusions or the mantle mixes with the meteoric waters to produce carbon dioxide waters: at considerable depth in the case of the thermal carbon dioxide waters but close to the surface in the case of cold carbon dioxide waters. The occurrence of carbon dioxide waters cannot be regarded as evidence for underground geothermal reservoirs. ?? 1983.

Arnorsson, S.; Barnes, I.

1983-01-01

296

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

Microsoft Academic Search

This report describes research conducted between April 1, 2005 and June 30, 2005 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas from coal combustion and synthesis gas from coal gasification. Supported sodium carbonate sorbents removed up to 76% of the carbon dioxide from simulated flue gas in a downflow cocurrent flow reactor system,

David A. Green; Thomas Nelson; Brian S. Turk; Paul Box; Weijiong Li; Raghubir P. Gupta

2005-01-01

297

Carbon Dioxide and the Greenhouse Effect: A Problem Evaluation Activity.  

ERIC Educational Resources Information Center

Describes exercises to examine the global carbon cycle. Students are asked to predict consequences of increased carbon dioxide emissions into the atmosphere and to suggest ways to mitigate problems associated with these higher levels of atmospheric carbon dioxide. A comparison modeling exercise examines some of the variables related to the success

Brewer, Carol A.; Beiswenger, Jane M.

1993-01-01

298

Thermochemical generation of hydrogen and carbon dioxide  

NASA Technical Reports Server (NTRS)

Mixing of carbon in the form of high sulfur coal with sulfuric acid reduces the temperature of sulfuric acid decomposition from 830.degree. C. to between 300.degree. C. and 400.degree. C. The low temperature sulfuric acid decomposition is particularly useful in thermal chemical cycles for splitting water to produce hydrogen. Carbon dioxide is produced as a commercially desirable byproduct. Lowering of the temperature for the sulfuric acid decomposition or oxygen release step simplifies equipment requirements, lowers thermal energy input and reduces corrosion problems presented by sulfuric acid at conventional cracking temperatures. Use of high sulfur coal as the source of carbon for the sulfuric acid decomposition provides an environmentally safe and energy efficient utilization of this normally polluting fuel.

Lawson, Daniel D. (Inventor); England, Christopher (Inventor)

1984-01-01

299

Atmospheric carbon dioxide and carbon reservoir changes.  

PubMed

The net release of CO(2) from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 x 10(9) tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th century the air had a CO(2) content of approximately 268 parts per millon, and the total increase in atmospheric CO(2) content since 1850 has been 18 percent. Major sinks for fossil fuel CO(2) are the thermocline regions of large oceanic gyres. About 34 percent of the excess CO(2) generated so far is stored in surface and thermocline gyre waters, and 13 percent has been advected into the deep sea. This leaves an airborne fraction of 53 percent. PMID:17759647

Stuiver, M

1978-01-20

300

Hemodynamic effects of carbon dioxide insufflation during endoscopic vein harvesting  

Microsoft Academic Search

Background. A prospective study was performed assessing the hemodynamic effects of carbon dioxide (CO2) insufflation during endoscopic vein harvesting (EVH) using the Guidant Vasoview Uniport system.Methods. Five hemodynamic and respiratory parameters (end-tidal carbon dioxide, arterial partial pressure of carbon dioxide, mean arterial pressure, mean pulmonary arterial pressure, and cardiac output), were measured in 100 consecutive patients undergoing EVH with CO2

Richard M Vitali; Ramachandra C Reddy; Peter J Molinaro; Mario F Sabado; Israel J Jacobowitz

2000-01-01

301

Preparation of perlite-based carbon dioxide absorbent.  

PubMed

A new highly efficient carbon dioxide absorbent consisting of sodium hydroxide, expanded perlite and acid-base indicator was prepared. The absorption efficiency, absorption capacity, flow resistance and color indication for the absorbent were tested and compared with some commercial products. The absorbent can reduce the carbon dioxide content in gases to 3.3 ppb (v/v) and absorbs not less than 35% of its weight of carbon dioxide. Besides its large capacity and sharp color indication, the absorbent has an outstanding advantage of small flow resistance in comparison with other commercial carbon dioxide absorbents. Applications in gas analysis and purification were also investigated. PMID:18965919

He, H; Wu, L; Zhu, J; Yu, B

1994-02-01

302

A tenuous carbon dioxide atmosphere on Jupiter's moon Callisto.  

PubMed

An off-limb scan of Callisto was conducted by the Galileo near-infrared mapping spectrometer to search for a carbon dioxide atmosphere. Airglow in the carbon dioxide nu3 band was observed up to 100 kilometers above the surface and indicates the presence of a tenuous carbon dioxide atmosphere with surface pressure of 7.5 x 10(-12) bar and a temperature of about 150 kelvin, close to the surface temperature. A lifetime on the order of 4 years is suggested, based on photoionization and magnetospheric sweeping. Either the atmosphere is transient and was formed recently or some process is currently supplying carbon dioxide to the atmosphere. PMID:9933159

Carlson, R W

1999-02-01

303

A tenuous carbon dioxide atmosphere on Jupiter's moon Callisto  

NASA Technical Reports Server (NTRS)

An off-limb scan of Callisto was conducted by the Galileo near-infrared mapping spectrometer to search for a carbon dioxide atmosphere. Airglow in the carbon dioxide nu3 band was observed up to 100 kilometers above the surface and indicates the presence of a tenuous carbon dioxide atmosphere with surface pressure of 7.5 x 10(-12) bar and a temperature of about 150 kelvin, close to the surface temperature. A lifetime on the order of 4 years is suggested, based on photoionization and magnetospheric sweeping. Either the atmosphere is transient and was formed recently or some process is currently supplying carbon dioxide to the atmosphere.

Carlson, R. W.

1999-01-01

304

High-pressure vapor-liquid equilibria of two binary systems: Carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone  

SciTech Connect

Vapor-liquid equilibria for carbon dioxide + cyclohexanol and carbon dioxide + cyclohexanone were measured using an apparatus based on a static-analytic method with in situ samplings. P, T, x, y measurements were made at pressures up to 22 MPa. The carbon dioxide + cyclohexanol system was studied at 433 and 473 K, and carbon dioxide + cyclohexanone, at 433 and 473 K. The results are correlated by the Redlich-Kwong-Soave and Peng and Robinson equations and several mixing rules. The best fittings are obtained with the Peng-Robinson equation of state and a two-parameter mixing rule, i.e., within 1.1% for both pressures and vapor mole fractions on the carbon dioxide + cyclohexanone system and within 1.9% for pressures and 2.9% for vapor mole fractions on the carbon dioxide + cyclohexanol system. More recent equations by Patel and Teja and Salim and Trebble show no significant advantages.

Laugier, S. [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France)] [Ecole Nationale Superieure de Chimie et Physique de Bordeaux, Talence (France); Richon, D. [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)] [Ecole Nationale Superieure des Mines de Paris, Fontainebleau (France)

1997-01-01

305

Development of a prototype regenerable carbon dioxide absorber  

NASA Technical Reports Server (NTRS)

Design information was obtained for a new, regenerable carbon dioxide control system for extravehicular activity life support systems. Solid potassium carbonate was supported in a thin porous sheet form and fabricated into carbon dioxide absorber units. Carbon dioxide and water in the life support system atmosphere react with the potassium carbonate and form potassium bicarbonate. The bicarbonate easily reverts to the carbonate by heating to 150 deg C. The methods of effectively packing the sorbent material into EVA-sized units and the effects of inlet concentrations, flowrate, and temperature upon performance were investigated. The cycle life of the sorbent upon the repeated thermal regenerations was demonstrated through 90 cycles.

Onischak, M.

1976-01-01

306

Cost analysis of carbon dioxide concentrators  

NASA Technical Reports Server (NTRS)

A methodology is developed to predict the relevant contributions of the more intangible cost elements encountered in the development of flight-qualified hardware and is used to predict the costs of three carbon dioxide concentration systems. The cost and performance data from Gemini, Skylab, and other programs are utilized as a basis for establishing the cost estimating relationships. The concentration systems analyzed are the molecular sieves C02 concentrator, the hydrogen-depolarized concentrator, and the regenerable solid desiccant concentrator. Besides the cost estimates for each system, their comparative criteria including relative characteristics, operational differences, and development status are considered.

Yakut, M. M.

1972-01-01

307

Searching for clues to ancient carbon dioxide  

SciTech Connect

Something on Earth just won't stop fiddling with the thermostat. In the past 500 million years, the planet has shivered through ice ages lasting millions of years and sweltered through episodes of global warmth. Climatologists, eager to know what keeps jiggling the planet's temperature setting, have focused their suspicions on carbon dioxide, the same heat-trapping gas expected to drive up temperatures in coming decades. Catching this suspect in the act has been difficult, however; the atmospheres of millions of years ago are gone with the wind.

Appenzeller, T.

1993-02-12

308

Electrochemical carbon dioxide concentrator subsystem development  

NASA Technical Reports Server (NTRS)

The fabrication of a one-person Electrochemical Depolarized Carbon Dioxide Concentrator subsystem incorporating advanced electrochemical, mechanical, and control and monitor instrumentation concepts is discussed. This subsystem included an advanced liquid cooled unitized core composite cell module and integrated electromechanical components. Over 1800 hours with the subsystem with removal efficiencies between 90%. and 100%; endurance tests with a Fluid Control Assembly which integrates 11 gas handling components of the subsystem; and endurance testing of a coolant control assembly which integrates a coolant pump, diverter valve and a liquid accumulator were completed.

Heppner, D. B.; Dahlausen, M. J.; Schubert, F. H.

1983-01-01

309

Carbon dioxide measurements in the stratosphere  

NASA Technical Reports Server (NTRS)

A mass spectrometer experiment for the analysis of minor constituents in the stratosphere has been flown successfully four times from Palestine, Texas on board a balloon gondola. The carbon dioxide mixing ratio, which shows unexpectedly large variations in the stratosphere, reached 400 ppm in one particular night flight. This is about 20% higher than the ground value. Evidence is presented that the experiment performed well during each of the balloon flights. The isotopic ratio C-12/C-13 was measured and found in good agreement with previous air analyses showing a depletion of C-13.

Mauersberger, K.; Finstad, R.

1980-01-01

310

Carbon dioxide capture and use: organic synthesis using carbon dioxide from exhaust gas.  

PubMed

A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO2) captured directly from exhaust gas was used for organic transformations as efficiently as hyper-pure CO2 gas from a commercial source, even for highly air- and moisture-sensitive reactions. The CO2 capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency. PMID:24307628

Kim, Seung Hyo; Kim, Kwang Hee; Hong, Soon Hyeok

2014-01-13

311

Vapor-liquid phase coexistence of alkane-carbon dioxide and perfluoroalkane-carbon dioxide mixtures  

Microsoft Academic Search

Both government and industry are seeking benign substitutes for the many organic solvents used in industry. Solvents are used as media for cleaning, for chemical reactions, and for chemical separation, and most of the solvents used are hazardous to health, safety, and the environment. Supercritical carbon dioxide (SC-CO) is often considered as an ideal solvent substitute, but several important classes

S. T. Cui; H. D. Cochran; P. T. Cummings

1999-01-01

312

40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.  

Code of Federal Regulations, 2013 CFR

...dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made with nondispersive infrared (NDIR) an analyzers. (b) The use of linearizing circuits is permitted. (c) The minimum water rejection...

2013-07-01

313

Modeling flow of mineralized carbon dioxide slurry  

SciTech Connect

Direct mineral carbonation was investigated at Albany Research Center (US DOE) as a means to sequester carbon dioxide into stable mineral matrices. Although previous work focused on treating Mg-containing minerals in conventional autoclaves, recent work has been done using pipeline-reactor technology for the high-temperature, high-pressure (HTHP) reaction of the minerals in aqueous/CO2 media. Sequestration of CO2 using above-ground reactors may be uneconomical, but the technology may also be applicable in geological sequestration of CO2. Progress is described in using a prototype HTHP flow-loop reactor to model flow in the dynamic three-phase system to help determine the pumping-energy requirements to optimize reactivity.

Penner, Larry R.; Dahlin, David C.; Gerdemann, Stephen J.; Saha, K.K. (Mechanical and Aerospace Engineering Dept., Computational Fluid Dynamics Laboratory, Arizona State University)

2005-04-01

314

Carbon dioxide enrichment inhibits nitrate assimilation in wheat and Arabidopsis.  

PubMed

The concentration of carbon dioxide in Earth's atmosphere may double by the end of the 21st century. The response of higher plants to a carbon dioxide doubling often includes a decline in their nitrogen status, but the reasons for this decline have been uncertain. We used five independent methods with wheat and Arabidopsis to show that atmospheric carbon dioxide enrichment inhibited the assimilation of nitrate into organic nitrogen compounds. This inhibition may be largely responsible for carbon dioxide acclimation, the decrease in photosynthesis and growth of plants conducting C(3) carbon fixation after long exposures (days to years) to carbon dioxide enrichment. These results suggest that the relative availability of soil ammonium and nitrate to most plants will become increasingly important in determining their productivity as well as their quality as food. PMID:20466933

Bloom, Arnold J; Burger, Martin; Rubio Asensio, Jose Salvador; Cousins, Asaph B

2010-05-14

315

The effect of elevated carbon dioxide on the growth and yield of wheat in the Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) experiment  

Microsoft Academic Search

Current predictions indicate that Australia is likely to be particularly challenged by the impacts of rising atmospheric carbon dioxide and the consequent perturbations in climate. The Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) project in Horsham, Victoria was designed to simulate predicted atmospheric carbon dioxide levels in the year 2050. The experiment measures the interacting effects of carbon dioxide

Rob Norton; Glenn Fitzgerald; Chris Korte

316

Chemical Reactions in Supercritical Carbon Dioxide  

NASA Astrophysics Data System (ADS)

Utilizing supercritical fluids as environmentally benign solvents for chemical synthesis is one of the new approaches in the "greening" of chemistry. Carbon dioxide is the most widely used gas for supercritical fluid studies because of its moderate critical constants, nontoxic nature, and availability in pure form. One unique property of supercritical carbon dioxide (sc-CO2) is its high solubility for fluorinated compounds. Thus sc-CO2 can be used to replace Freons that are conventionally used as solvents for synthesis of perfluoro-polymers. Another property of sc-CO2 is its miscibility with gases such as H2. Heterogeneous reactions involving these gases may become homogeneous reactions in sc-CO2. Reactions in sc-CO2 may offer several advantages including controlling phase behavior and products, increasing speed of reactions, and obtaining specific reaction channels. This paper describes the following nine types of chemical reactions reported in the literature utilizing sc-CO2 as a solvent to illustrate the unique properties of the supercritical fluid reaction systems: (i) hydrogenation and hydroformylation, (ii) synthesis of organometallic compounds, (iii) metal chelation and extraction, (iv) preparation of inorganic nanoparticles, (v) stereo-selectivity of lipase-catalyzed reactions, (vi) asymmetric catalytic hydrogenation, (vii) polymerization, (viii) Diels-Alder reaction, and (ix) free radical reactions.

Wai, Chien M.; Hunt, Fred; Ji, Min; Chen, Xiaoyuan

1998-12-01

317

Six-fold coordinated carbon dioxide VI  

NASA Astrophysics Data System (ADS)

Under standard conditions, carbon dioxide (CO2) is a simple molecular gas and an important atmospheric constituent, whereas silicon dioxide (SiO2) is a covalent solid, and one of the fundamental minerals of the planet. The remarkable dissimilarity between these two group IV oxides is diminished at higher pressures and temperatures as CO2 transforms to a series of solid phases, from simple molecular to a fully covalent extended-solid V, structurally analogous to SiO2 tridymite. Here, we present the discovery of an extended-solid phase of CO2: a six-fold coordinated stishovite-like phase VI, obtained by isothermal compression of associated CO2-II (refs 1,2) above 50GPa at 530-650K. Together with the previously reported CO2-V (refs 3-5) and a-carbonia, this extended phase indicates a fundamental similarity between CO2 (a prototypical molecular solid) and SiO2 (one of Earth's fundamental building blocks). We present a phase diagram with a limited stability domain for molecular CO2-I, and suggest that the conversion to extended-network solids above 40-50GPa occurs via intermediate phases II (refs 1,2), III (refs 7,8) and IV (refs 9,10). The crystal structure of phase VI suggests strong disorder along the c axis in stishovite-like P42/mnm, with carbon atoms manifesting an average six-fold coordination within the framework of sp3 hybridization.

Iota, Valentin; Yoo, Choong-Shik; Klepeis, Jae-Hyun; Jenei, Zsolt; Evans, William; Cynn, Hyunchae

2007-01-01

318

The Carbon Dioxide Greenhouse: Is It Effective?  

NSDL National Science Digital Library

This activity allows students to compare the thermal properties of carbon dioxide with those of air, and can be extended to compare water vapor as well. Students discover that the gas which absorbs the most heat (infrared radiation) is the most effective greenhouse gas because in the atmosphere it would absorb more infrared coming from the surface of the Earth. This activity could be used as either a demonstration or a laboratory activity depending on the availability of equipment. Either a data logger is used to record the changing temperature of air and of carbon dioxide in plastic bottles as they are heated using electric lamps, and then allowed to cool, or if a data logger is not available, then thermometers can be used instead and monitored by students. The site contains teacher notes and instructions with a list of materials and a photograph showing the setup. It also has an introduction for the students and questions for them to answer along with a glossary.

319

Reactions of Carbon Dioxide with Silicates under High Pressures.  

National Technical Information Service (NTIS)

Reactions of carbon dioxide with molten glass under high pressures were studied. Two special types of apparatus were employed. The results supported the existence of equilibria between silicates and carbonates. No evidence was found for the existence of e...

W. Weyl

1975-01-01

320

66 FR 66994 - Controlling Corrosion on Hazardous Liquid and Carbon Dioxide Pipelines  

Federal Register 2010, 2011, 2012, 2013

...195 Controlling Corrosion on Hazardous Liquid and Carbon Dioxide Pipelines; Final Rule...2137-AD24 Controlling Corrosion on Hazardous Liquid and Carbon Dioxide Pipelines AGENCY...corrosion control standards for hazardous liquid and carbon dioxide pipelines. The...

2001-12-27

321

46 CFR 34.15-20 - Carbon dioxide storage-T/ALL.  

Code of Federal Regulations, 2013 CFR

... false Carbon dioxide storage-T/ALL. 34.15-20 Section 34.15-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...Carbon Dioxide Extinguishing Systems, Details § 34.15-20 Carbon dioxide storageT/ALL....

2013-10-01

322

76 FR 55846 - Hazardous Waste Management System: Identification and Listing of Hazardous Waste: Carbon Dioxide...  

Federal Register 2010, 2011, 2012, 2013

...Listing of Hazardous Waste: Carbon Dioxide (CO2) Streams in Geologic Sequestration Activities AGENCY: Environmental...to conditionally exclude carbon dioxide (CO 2 ) streams...to conditionally exclude carbon dioxide (CO 2 )...

2011-09-09

323

Hydrodynamic Controls on Carbon Dioxide Efflux from Inland Waters  

NASA Astrophysics Data System (ADS)

Intensive research has been undertaken on carbon dioxide efflux from lakes, estuaries and oceans, but much less attention has been given to rivers and streams, especially lower order streams. River systems are often over-saturated with carbon dioxide and so tend to act as sources of carbon dioxide to the atmosphere. It has been thought that rivers act as pipes carrying this terrestrial carbon to the oceans. However, recent studies have shown that a significant amount of the carbon is reprocessed within the system in a series of transformations and losses. Fluvial evasion of carbon dioxide is now recognised to be a significant component of carbon cycles, however the factors controlling carbon dioxide efflux and its magnitude remain poorly understood and quantified. This research aims to quantify, and better understand the controls on, freshwater carbon dioxide evasion. Data are presented here from field measurements that commenced in Sept 2013 in two contrasting Scottish rivers: the River Kelvin which has a large (335 km.sq) part-urban catchment with predominantly non-peat soils and Drumtee Water, a small (9.6 km.sq) rural catchment of peat soils and agricultural land. Using a floating chamber with the headspace connected to an infrared gas analyser to measure changes in carbon dioxide concentration, efflux rates from 0.22 - 47.4 ?mol CO2/m.sq/sec were measured, these close to the middle of the range of previously reported values. At one site on the River Kelvin in May 2013 an influx of -0.61 - -3.53 ?mol CO2/m.sq/sec was recorded. Whereas previous research finds carbon dioxide efflux to increase with decreasing river size and a more organic-rich soil catchment, here the controls on carbon dioxide evasion are similar across the contrasting catchments. Carbon dioxide evasion shows seasonality, with maximum fluxes in the summer months being up to twice as high as the winter maxima. Linear regression demonstrates that evasion increases with increased flow velocity, water surface disturbance indicated by Froude number, and turbulent mixing indicated by Reynolds number. Similar relationships with season, flow velocity and turbulence have been reported previously, but there is little known about the mechanisms involved. When comparing spot carbon dioxide efflux measurements to river stage time series data, carbon dioxide efflux is more sensitive to an increase in stage at more turbulent measurement points. Further investigation of the mechanisms will be obtained by measurement of DIC concentration and isotopic composition to assess the controls of carbon source versus degassing, and the analysis of the interactions between hydraulic and seasonal controls and carbon dioxide fluxes extended.

Long, H. E.; Waldron, S.; Hoey, T.; Newton, J.; Quemin, S.

2013-12-01

324

Foaming agents for carbon dioxide and steam floods  

Microsoft Academic Search

This patent describes improvement in a steam flood or carbon dioxide flood in an underground hydrocarbon formation. The improvement comprises: injecting into an injection well above 0.05% to about 5% by weight aqueous surfactant solution which will foam and reduce the permeability of swept zones, forcing steam or carbon dioxide into unswept areas of the formation, the aqueous surfactant solution

Naae

1991-01-01

325

Solid amine compounds as sorbents for carbon dioxide: A concept  

NASA Technical Reports Server (NTRS)

Solid amine compounds were examined as possible absorbents for removal of carbon dioxide in life support systems of type which may be employed in high altitude aircraft, spacecraft, or submarines. Many solid amine compounds release absorbed carbon dioxide when heated in vacuum, therefore, when properly packaged spent amine compounds can be readily regenerated and put back into service.

Sutton, J. G.; Heimlich, P. F.; Tepper, E. H.

1972-01-01

326

Absorption of Carbon Dioxide in Waste Tanks (September 3, 1987).  

National Technical Information Service (NTIS)

Air flow rates and carbon dioxide concentrations of air entering and exiting eight H-Area waste tanks were monitored for a period of one year. The average instanteous concentration of carbon dioxide in air is within the range reported offsite, and therefo...

D. T. Hobbs

1987-01-01

327

An Electrochemical Technic for Measuring Carbon Dioxide Content of Blood.  

National Technical Information Service (NTIS)

An electrochemical technic for measuring carbon dioxide content in whole blood has been devised and evaluated. This technic has been extended to measure the Bunsen solubility coefficient of carbon dioxide. The method requires a membrane-covered pH electro...

R. J. Reyes J. R. Neville

1967-01-01

328

Drug pharmacokinetics and the carbon dioxide breath test  

Microsoft Academic Search

The interrelationship of the pharmacokinetics of a drug and the expiration of carbon dioxide formed as a metabolite have been studied. The pharmacokinetic characteristics of the drug that affect the usefulness of the carbon dioxide excretion as a measure of liver function were examined by means of computer simulations. The parent drug extraction ratio, fraction demethylated, volume of distribution, and

Ioanis Parashos

1986-01-01

329

The acid rain\\/carbon dioxide threat Control strategies  

Microsoft Academic Search

Many of the world's most troublesome problems are closely interrelated. A case in point is the acid rain\\/carbon dioxide threat. Acid rain is the commonly used synonym for the major ingredients in the ongoing regional forest dieback, and carbon dioxide is a major influencing factor in the man-induced global geophysical experiment which is feared to lead to unacceptable climatic changes.

Wilfrid Bach

1985-01-01

330

Carbon dioxide and climate: Summaries of research in FY 1988  

SciTech Connect

Detailed worldwide measurements indicate that the amount of carbon dioxide in the earth's atmosphere has increased about 25 percent during the past 188 years, primarily because of fossil-fuel combustion and deforestation. Carbon dioxide is one of several trace gases that can modify the earth's heat balance by absorbing outgoing radiation from the earth's surface, thereby increasing the amount of heat retained by the atmosphere--the so-called greenhouse effect. Scientific analyses suggest that this increase could substantially affect climate, agriculture, and other human endeavors. The Carbon Dioxide Research Program is aimed at improving the scientific knowledge base to enable researchers to project future atmospheric concentrations of carbon dioxide, to estimate carbon dioxide-induced global and regional climate changes, and to assess the responses of vegetation to higher concentrations of carbon dioxide and changing climate. The Department of Energy is the lead federal agency for research related to atmospheric carbon dioxide. Its responsibility is to sponsor a program of directed research and to coordinate this research with relevant activities of other federal agencies, private concerns, and international institutions. This Program Summary documents the activities and products of the Carbon Dioxide Research (CDR) Program in Fiscal Year 1988. The Summary provides descriptions of all projects funded during the year and a brief overview of the CDR Program's goals, objectives, and organization. 1 fig., 3 tabs.

Not Available

1988-10-01

331

Carbon Dioxide Changes During the Last 400,000 years  

NSDL National Science Digital Library

In this problem set, learners will analyze a graph of carbon dioxide concentration in the last 400,000 years and consider the rise in carbon dioxide of the last 150 years. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

332

Flexible substrates as basis for photocatalytic reduction of carbon dioxide  

Microsoft Academic Search

A photocatalytic system for converting carbon dioxide into carbon monoxide was designed and constructed. The system relies on thin films of the photocatalyst prepared at low temperature using spray coating. We formulated inks based on the well-known photocatalyst titanium dioxide and characterized the performance in this setting. Glass substrates were used for model studies with an active area of 100cm2

Jacob Jensen; Mette Mikkelsen; Frederik C. Krebs

2011-01-01

333

Ocean Acidification Consequences of Stabilization of Atmospheric Carbon Dioxide  

Microsoft Academic Search

We investigate ocean chemistry changes that would result from the stabilization of atmospheric carbon dioxide concentrations at different levels. To determine the fate of ocean chemistry after atmospheric carbon dioxide is stabilized, we perform a suite of simulations using the UVic Earth system model in which atmospheric CO2 is stabilized at levels ranging from 280 ppm to 5000 ppm. Atmospheric

L. Cao; K. Caldeira

2007-01-01

334

Climate Science in a Nutshell: Where Carbon Dioxide Come From?  

NSDL National Science Digital Library

This short video discusses where carbon dioxide, the gas that is mainly responsible for warming up our planet and changing the climate, comes from. It discusses how the rise in atmospheric carbon dioxide comes directly from the burning of fossil fuels and indirectly from the human need for energy.

Nutshell, Planet; Network, Utah E.

335

Herbivore responses to plants grown in enriched carbon dioxide atmospheres  

Microsoft Academic Search

Our initial study of sagebrush and grasshopper responses to elevated and historical carbon dioxide atmospheres is complete and has been accepted for publication. The study on Biomass Allocation Patterns of Defoliated Sagebrush Grown Under Two Levels of Carbon Dioxide has completed and the manuscript has been submitted for publication. We have completed the study of plant growth under two nutrient

Lincoln

1990-01-01

336

A Tenuous Carbon Dioxide Atmosphere on Jupiter's Moon Callisto  

Microsoft Academic Search

An off-limb scan of Callisto was conducted by the Galileo Near Infrared Mapping Spectrometer to search for a carbon dioxide atmosphere. Airglow in the CO, v,, band was observed up to 100 km above the surface and indicates the presence of a tenuous carbon dioxide atmosphere with surface pressure of 7.5 x 10\\

Robert W. Carlson

1999-01-01

337

Carbon dioxide sequestration by ex-situ mineral carbonation  

SciTech Connect

The process developed for carbon dioxide sequestration utilizes a slurry of water mixed with olivine- forsterite end member (Mg{sub 2}SiO{sub 4}), which is reacted with supercritical CO{sub 2} to produce magnesite (MgCO{sub 3}). Carbon dioxide is dissolved in water to form carbonic acid, which likely dissociates to H{sup +} and HCO{sub 3}{sup -}. The H{sup +} hydrolyzes the silicate mineral, freeing the cation (Mg{sup 2+}), which reacts with the HCO{sub 3}{sup -} to form the solid carbonate. Results of the baseline tests, conducted on ground products of the natural mineral, have demonstrated that the kinetics of the reaction are slow at ambient temperature (22 degrees C) and subcritical CO{sub 2} pressures (below 7.4 MPa). However, at elevated temperature and pressure, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant conversion to the carbonate occurs. Extent of reaction is roughly 90% within 24 h, at 185 degrees C and partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 11.6 MPa. Current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, and/or solution modification. Subsequent tests are intended to examine these options, as well as other mineral groups.

O'Connor, W.K.; Dahlin, D.C.; Turner, P.C.; and Walters, R.P.

2000-01-01

338

Carbon dioxide absorbent and method of using the same  

DOEpatents

In accordance with one aspect, the present invention provides an amino-siloxane composition comprising at least one of structures I, II, III, IV or V said compositions being useful for the capture of carbon dioxide from gas streams such as power plant flue gases. In addition, the present invention provides methods of preparing the amino-siloxane compositions are provided. Also provided are methods for reducing the amount of carbon dioxide in a process stream employing the amino-siloxane compositions of the invention as species which react with carbon dioxide to form an adduct with carbon dioxide. The reaction of the amino-siloxane compositions provided by the present invention with carbon dioxide is reversible and thus, the method provides for multicycle use of said compositions.

Perry, Robert James (Niskayuna, NY); Lewis, Larry Neil (Scotia, NY); O'Brien, Michael Joseph (Clifton Park, NY); Soloveichik, Grigorii Lev (Latham, NY); Kniajanski, Sergei (Clifton Park, NY); Lam, Tunchiao Hubert (Clifton Park, NY); Lee, Julia Lam (Niskayuna, NY); Rubinsztajn, Malgorzata Iwona (Ballston Spa, NY)

2011-10-04

339

Carbon dioxide stripping in aquaculture. part 1: terminology and reporting  

USGS Publications Warehouse

The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ? H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (<2000 ?eq/kg), the difference between the true and apparent removal is small and can be ignored for many applications. Analytical and reporting standards are recommended to improve our understanding of carbon dioxide removal.

Colt, John; Watten, Barnaby; Pfeiffer, Tim

2012-01-01

340

Ruthenium-catalysed alkoxycarbonylation of alkenes with carbon dioxide.  

PubMed

Alkene carbonylations represent a major technology for the production of value-added bulk and fine chemicals. Nowadays, all industrial carbonylation processes make use of highly toxic and flammable carbon monoxide. Here we show the application of abundantly available carbon dioxide as C1 building block for the alkoxycarbonylations of industrially important olefins in the presence of a convenient and inexpensive ruthenium catalyst system. In our system, carbon dioxide works much better than the traditional combination of carbon monoxide and alcohols. The unprecedented in situ formation of carbon monoxide from carbon dioxide and alcohols permits an efficient synthesis of carboxylic acid esters, which can be used as detergents and polymer-building blocks. Notably, this transformation allows the catalytic formation of C-C bonds with carbon dioxide as C1 source and avoids the use of sensitive and/or expensive reducing agents (for example, Grignard reagents, diethylzinc or triethylaluminum). PMID:24518431

Wu, Lipeng; Liu, Qiang; Fleischer, Ivana; Jackstell, Ralf; Beller, Matthias

2014-01-01

341

Sulfur dioxide absorption at DF laser wavelengths  

NASA Astrophysics Data System (ADS)

The absorption of DF laser lines by sulfur dioxide under atmospheric conditions is measured in light of the possible application of optical methods to the detection of the atmospheric pollutant. Absorption measurements were performed for 20 DF laser wavelengths between 2792 and 2509 kaysers in a multipass absorption cell. Weak absorption is detected around a wavelength of 3.7 microns and is attributed to the 2 nu 3 band of SO2. The P 4(6) line at 3.9843 microns is found to be strongly absorbed by the (nu 1 + nu 3) band of SO2, with a specific absorption coefficient of 0.44 + or - 0.01/cm per atm, which indicates that strong SO2 emissions in the atmosphere can be detected optically. Measurements of the pressure dependence of the absorption coefficient of the P4(6) line reveal broadening coefficients between 1.5 and 5 MHz/Torr, depending on line strength, and a wavenumber difference of 0.0043 + or - 0.0004 kaysers from the P4(6) DF line to the center of the nearest SO2 line.

Altmann, J.; Pokrowsky, P.

1980-10-01

342

Carbon dioxide hydrogenation on Ni(110).  

PubMed

We demonstrate that the key step for the reaction of CO 2 with hydrogen on Ni(110) is a change of the activated molecule coordination to the metal surface. At 90 K, CO 2 is negatively charged and chemically bonded via the carbon atom. When the temperature is increased and H approaches, the H-CO 2 complex flips and binds to the surface through the two oxygen atoms, while H binds to the carbon atom, thus yielding formate. We provide the atomic-level description of this process by means of conventional ultrahigh vacuum surface science techniques combined with density functional theory calculations and corroborated by high pressure reactivity tests. Knowledge about the details of the mechanisms involved in this reaction can yield a deeper comprehension of heterogeneous catalytic organic synthesis processes involving carbon dioxide as a reactant. We show why on Ni the CO 2 hydrogenation barrier is remarkably smaller than that on the common Cu metal-based catalyst. Our results provide a possible interpretation of the observed high catalytic activity of NiCu alloys. PMID:18665600

Vesselli, Erik; De Rogatis, Loredana; Ding, Xunlei; Baraldi, Alessandro; Savio, Letizia; Vattuone, Luca; Rocca, Mario; Fornasiero, Paolo; Peressi, Maria; Baldereschi, Alfonso; Rosei, Renzo; Comelli, Giovanni

2008-08-27

343

Global carbon dioxide emissions from inland waters.  

PubMed

Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity. We obtain global CO2 evasion rates of 1.8(+0.25)(-0.25)? petagrams of carbon (Pg?C) per year from streams and rivers and 0.32(+0.52)(-0.26)? Pg?C?yr(-1) from lakes and reservoirs, where the upper and lower limits are respectively the 5th and 95th confidence interval percentiles. The resulting global evasion rate of 2.1?Pg?C?yr(-1) is higher than previous estimates owing to a larger stream and river evasion rate. Our analysis predicts global hotspots in stream and river evasion, with about 70 per cent of the flux occurring over just 20 per cent of the land surface. The source of inland water CO2 is still not known with certainty and new studies are needed to research the mechanisms controlling CO2 evasion globally. PMID:24256802

Raymond, Peter A; Hartmann, Jens; Lauerwald, Ronny; Sobek, Sebastian; McDonald, Cory; Hoover, Mark; Butman, David; Striegl, Robert; Mayorga, Emilio; Humborg, Christoph; Kortelainen, Pirkko; Drr, Hans; Meybeck, Michel; Ciais, Philippe; Guth, Peter

2013-11-21

344

Calcium Oxide Matrices and Carbon Dioxide Sensors  

PubMed Central

Homogeneous matrices of calcium oxide (CaO) were prepared by mixing this material with polyethylene glycol (PEG) acting as malleable inert support in order to obtain processable composites. Preliminary tests were carried out to assess the best concentration of CaO in the composite, individuated in the CaO/PEG weight ratio of 1/4. Experimental data highlighted that the composite was able to selectively detect carbon dioxide (CO2) via a nanogravimetric method by performing the experiments inside an atmosphere-controlled chamber filled with CO2. Furthermore, the composite material showed a linear absorption of CO2 as a function of the gas concentration inside the atmosphere-controlled chamber, thus paving the way for the possible use of these matrices for applications in the field of sensor devices for long-term evaluation of accumulated environmental CO2.

Terencio, Tercio Bezerra Correia; Bavastrello, Valter; Nicolini, Claudio

2012-01-01

345

Thermodynamical effects during carbon dioxide release  

NASA Astrophysics Data System (ADS)

Pruess [1] investigated the risk of carbon dioxide leakage from shallow storage sites by modeling scenarios. Such a fluid release is associated with mechanical work performed by formation fluid against expansion without taking heat from ambient environment. Understanding of heat related to mechanical work is essential to predict the temperature at the leak. According to the first law of thermodynamics, internal energy of working fluid decreases with an amount which is equivalent to this work hence, working fluid lost its own heat. Such kind of heat loss depends strongly on whether the expansion process is adiabatic or isothermal. Isothermal expansion allows the working fluid to interact thermally with the solid matrix. Adiabatic expansion is an isenthalpic process that takes heat from the working fluid and the ambient environment remains unchanged. This work is part of the CLEAN research project [6]. In this study, thermodynamic effects of mechanical work during eventual carbon dioxide leakage are investigated numerically. In particular, we are interested to detect the temperature at leakage scenarios and its deviation with different thermodynamic processes. Finite element simulation is conducted with a two-dimensional rectangular geometry representing a shallow storage site which bottom was located at -300m below the land surface. A fully saturated porous medium is assumed where the pore space is filled completely with carbon dioxide. Carbon dioxide accumulated in the secondary trap at 30 Bar and 24 C is allowed to leak from top right point of rectangle with atmospheric pressure. With (i) adiabatic and (ii) isothermal compressibility factors, temperature around leakage area has been calculated which show a significant difference. With some simplification, this study detects leak temperature which is very close with [1]. Temporal evaluation at the leaky area shows that the working fluid temperature can be reduced to -20 C when the leakage scenario is performed under isothermal expansion. Under adiabatic expansion, further reduction in the working fluid temperature can be expected. The governing equations from mass and energy balance laws of porous media mechanics are used for problem description. Pressure and fluid phase temperature are chosen as the primary variables. Extended ideal gas law is used with super compressibility factor (SCF) to predict real gas density for large range of pressure and temperature [2]. Cubic equation based on Peng-Robinson equation of state was solved analytically for SCF [3]. Real fluid properties, such as dynamic viscosity, thermal conductivity and specific heat capacity used in this study are density and temperature dependent. Analytical expression for the derivatives of SCF with respect to temperature and pressure are used. Subsequently, these derivatives are utilized to define isothermal compressibility, adiabatic compressibility and thermal expansion coefficient for the real gas. These parameters can influence heat loss due to thermodynamic effects significantly. The governing equations are discretized spatially within the Galerkin approach, whereas for the temporal discretization, we adopt generalized single step method [5]. The coupled system of governing equations is solved in a monolithic way with variable time stepping. The numerical module has been implemented within the open source object-oriented finite element code OpenGeoSys [4].

Singh, A. K.; Bttcher, N.; Grke, U.-J.; Kolditz, O.

2012-04-01

346

Calcium oxide matrices and carbon dioxide sensors.  

PubMed

Homogeneous matrices of calcium oxide (CaO) were prepared by mixing this material with polyethylene glycol (PEG) acting as malleable inert support in order to obtain processable composites. Preliminary tests were carried out to assess the best concentration of CaO in the composite, individuated in the CaO/PEG weight ratio of 1/4. Experimental data highlighted that the composite was able to selectively detect carbon dioxide (CO(2)) via a nanogravimetric method by performing the experiments inside an atmosphere-controlled chamber filled with CO(2). Furthermore, the composite material showed a linear absorption of CO(2) as a function of the gas concentration inside the atmosphere-controlled chamber, thus paving the way for the possible use of these matrices for applications in the field of sensor devices for long-term evaluation of accumulated environmental CO(2). PMID:22778620

Terencio, Tercio Bezerra Correia; Bavastrello, Valter; Nicolini, Claudio

2012-01-01

347

Carbon dioxide-in-water microemulsions.  

PubMed

Liquid and supercritical carbon dioxide swell potassium carboxylate perfluoropolyether (PFPE-K) cylindrical micelles in water to produce novel CO(2)-in-water (C/W) microemulsions. The swelling elongates the micelles significantly from 20 to 80 nm as the molar ratio of CO(2) in the micelles to surfactant (R(CO2)) reaches approximately 8. As the micelles swell to form microemulsions, the solubility of pyrene increases by a factor of ca. 10. Fluorescence spectra suggest that pyrene resides primarily in the low-polarity micelle core rather than in the palisade region. The results illustrate the ability of C/W microemulsions to solubilize both lipophilic and fluorophilic substances simultaneously. PMID:12617686

Lee, C Ted; Ryoo, Won; Smith, P Griffin; Arellano, Jose; Mitchell, Daniel R; Lagow, Richard J; Webber, Stephen E; Johnston, Keith P

2003-03-12

348

The Fluid Mechanics of Carbon Dioxide Sequestration  

NASA Astrophysics Data System (ADS)

Humans are faced with a potentially disastrous global problem owing to the current emission of 32 gigatonnes of carbon dioxide (CO2) annually into the atmosphere. A possible way to mitigate the effects is to store CO2 in large porous reservoirs within the Earth. Fluid mechanics plays a key role in determining both the feasibility and risks involved in this geological sequestration. We review current research efforts looking at the propagation of CO2 within the subsurface, the possible rates of leakage, the mechanisms that act to stably trap CO2, and the geomechanical response of the crust to large-scale CO2 injection. We conclude with an outline for future research.

Huppert, Herbert E.; Neufeld, Jerome A.

2014-01-01

349

Coiled tubing drilling with supercritical carbon dioxide  

DOEpatents

A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO.sub.2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO.sub.2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC--CO.sub.2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC--CO.sub.2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC--CO.sub.2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC--CO.sub.2 much more effective than water jet erosion. SC--CO.sub.2 jets can be used to assist mechanical drilling, for erosion drilling, or for scale removal. A choke manifold at the well head or mud cap drilling equipment can be used to control the pressure within the borehole, to ensure that the temperature and pressure conditions necessary for CO.sub.2 to exist as either a supercritical fluid or a dense gas occur at the drill site. Spent CO.sub.2 can be vented to the atmosphere, collected for reuse, or directed into the formation to aid in the recovery of petroleum.

Kolle , Jack J. (Seattle, WA)

2002-01-01

350

Six-fold coordinated carbon dioxide VI.  

PubMed

Under standard conditions, carbon dioxide (CO2) is a simple molecular gas and an important atmospheric constituent, whereas silicon dioxide (SiO2) is a covalent solid, and one of the fundamental minerals of the planet. The remarkable dissimilarity between these two group IV oxides is diminished at higher pressures and temperatures as CO2 transforms to a series of solid phases, from simple molecular to a fully covalent extended-solid V, structurally analogous to SiO2 tridymite. Here, we present the discovery of an extended-solid phase of CO2: a six-fold coordinated stishovite-like phase VI, obtained by isothermal compression of associated CO2-II (refs 1,2) above 50 GPa at 530-650 K. Together with the previously reported CO2-V (refs 3-5) and a-carbonia, this extended phase indicates a fundamental similarity between CO2 (a prototypical molecular solid) and SiO2 (one of Earth's fundamental building blocks). We present a phase diagram with a limited stability domain for molecular CO2-I, and suggest that the conversion to extended-network solids above 40-50 GPa occurs via intermediate phases II (refs 1,2), III (refs 7,8) and IV (refs 9,10). The crystal structure of phase VI suggests strong disorder along the c axis in stishovite-like P42/mnm, with carbon atoms manifesting an average six-fold coordination within the framework of sp3 hybridization. PMID:17160005

Iota, Valentin; Yoo, Choong-Shik; Klepeis, Jae-Hyun; Jenei, Zsolt; Evans, William; Cynn, Hyunchae

2007-01-01

351

Intraosseous Venography with Carbon Dioxide in Percutaneous Vertebroplasty: Carbon Dioxide Retention in Renal Veins  

SciTech Connect

The objective of the present study was to determine the frequency of gas retention in the renal vein following carbon dioxide intraosseous venography in the prone position and, while citing references, to examine its onset mechanisms. All percutaneous vertebroplasties performed at our hospital from January to December 2005 were registered and retrospectively analyzed. Of 43 registered procedures treating 79 vertebrae, 28 procedures treating 54 vertebrae were analyzed. Vertebral intraosseous venography was performed using carbon dioxide as a contrast agent in all percutaneous vertebroplasty procedures. In preoperative and postoperative vertebral CT, gas retention in the renal vein and other areas was assessed. Preoperative CT did not show gas retention (0/28 procedures; 0%). Postoperative CT confirmed gas retention in the renal vein in 10 of the 28 procedures (35.7%). Gas retention was seen in the right renal vein in 8 procedures (28.6%), in the left renal vein in 5 procedures (17.9%), in the left and right renal veins in 3 procedures (10.7%), in vertebrae in 22 procedures (78.6%), in the soft tissue around vertebrae in 14 procedures (50.0%), in the spinal canal in 12 procedures (42.9%), and in the subcutaneous tissue in 5 procedures (17.9%). In conclusion, in our study, carbon dioxide gas injected into the vertebra frequently reached and remained in the renal vein.

Komemushi, Atsushi, E-mail: kome64@yo.rim.or.jp; Tanigawa, Noboru; Kariya, Shuji; Kojima, Hiroyuki; Shomura, Yuzo; Tokuda, Takanori; Nomura, Motoo; Terada, Jiro; Kamata, Minoru; Sawada, Satoshi [Kansai Medical University, Department of Radiology (Japan)

2008-11-15

352

Laser Cladding on Carbon-Carbon Composites.  

National Technical Information Service (NTIS)

This report describes the results of experiments on laser cladding a variety of protective coatings onto carbon-carbon substrates as oxidation- protection coatings. The work was performed using a 12-kW flattop CO2 laser and a powder delivery system to inj...

J. J. Eric R. J. Hull

2002-01-01

353

Estimated Carbon Dioxide Emissions in 2008: United States  

SciTech Connect

Flow charts depicting carbon dioxide emissions in the United States have been constructed from publicly available data and estimates of state-level energy use patterns. Approximately 5,800 million metric tons of carbon dioxide were emitted throughout the United States for use in power production, residential, commercial, industrial, and transportation applications in 2008. Carbon dioxide is emitted from the use of three major energy resources: natural gas, coal, and petroleum. The flow patterns are represented in a compact 'visual atlas' of 52 state-level (all 50 states, the District of Columbia, and one national) carbon dioxide flow charts representing a comprehensive systems view of national CO{sub 2} emissions. Lawrence Livermore National Lab (LLNL) has published flow charts (also referred to as 'Sankey Diagrams') of important national commodities since the early 1970s. The most widely recognized of these charts is the U.S. energy flow chart (http://flowcharts.llnl.gov). LLNL has also published charts depicting carbon (or carbon dioxide potential) flow and water flow at the national level as well as energy, carbon, and water flows at the international, state, municipal, and organizational (i.e. United States Air Force) level. Flow charts are valuable as single-page references that contain quantitative data about resource, commodity, and byproduct flows in a graphical form that also convey structural information about the system that manages those flows. Data on carbon dioxide emissions from the energy sector are reported on a national level. Because carbon dioxide emissions are not reported for individual states, the carbon dioxide emissions are estimated using published energy use information. Data on energy use is compiled by the U.S. Department of Energy's Energy Information Administration (U.S. EIA) in the State Energy Data System (SEDS). SEDS is updated annually and reports data from 2 years prior to the year of the update. SEDS contains data on primary resource consumption, electricity generation, and energy consumption within each economic sector. Flow charts of state-level energy usage and explanations of the calculations and assumptions utilized can be found at: http://flowcharts.llnl.gov. This information is translated into carbon dioxide emissions using ratios of carbon dioxide emissions to energy use calculated from national carbon dioxide emissions and national energy use quantities for each particular sector. These statistics are reported annually in the U.S. EIA's Annual Energy Review. Data for 2008 (US. EIA, 2010) was updated in August of 2010. This is the first presentation of a comprehensive state-level package of flow charts depicting carbon dioxide emissions for the United States.

Smith, C A; Simon, A J; Belles, R D

2011-04-01

354

Carbon Dioxide in the Gulf of Trieste  

NASA Astrophysics Data System (ADS)

Coastal marine regions such as the Gulf of Trieste (GOT) in the Northern Adriatic Sea serve as the link between carbon cycling on land and the ocean interior and potentially contribute large uncertainties in the estimate of anthropogenic CO2 uptake. This system may be either a sink or a source for atmospheric CO2. Understanding the sources and sinks as a result of biological and physical controls for air-sea carbon dioxide fluxes in coastal waters may substantially alter the current view of the global carbon budget for unique terrestrial and ocean regions such as the GOT. GOT is a semi-enclosed Mediterranean basin situated in the northern part of Adriatic Sea. It is one of the most productive regions in the Mediterranean and is affected by extreme fresh river input, phytoplankton blooms, and large changes of air-sea exchange during Bora high wind events. The unique combination of these environmental processes and relatively small size of the area makes the region an excellent study site for investigations of air-sea interaction, and changes in biology and carbon chemistry. Here we investigate biological (phytoplankton blooms) and physical (freshwater input and winds) controls on the temporal variability of pCO2 in the GOT. The aqueous CO2 was measured at the Coastal Oceanographic buoy VIDA, Slovenia using the SAMI CO2 sensor. Our results indicate that: 1) The GOT was a sink for atmospheric CO2 in late spring of 2007; 2) Aqueous pCO2 was influenced by fresh water input from rivers entering the GOT and biological production associated with high nutrient input; 3) Surface water pCO2 showed a strong correlation with SST when river plumes where not present at the buoy location, and reasonable correlation with SSS during the presence of the plume.

Turk, D.; Malacic, V.; Degrandpre, M. D.; McGillis, W. R.

2009-04-01

355

Redox Reactions of Metalloporphyrins and their Role in Catalyzed Reduction of Carbon Dioxide  

SciTech Connect

Pulse radiolysis and laser photolysis are used to study redox processes of metalloporphyrins and related complexes in order to evaluate these light absorbing molecules as sensitizers and intermediates in solar energy conversion schemes. The main thrust of the current studies is to investigate the role of reduced metalloporphyrins as intermediates in the catalyzed reduction of carbon dioxide. Studies involve cobalt and iron porphyrins, phthalocyanines, corroles, and corrins as homogeneous catalysts for reduction of carbon dioxide in solution. The main aim is to understand the mechanisms of these photochemical schemes in order to facilitate their potential utilization.

Neta, P.

2002-09-01

356

Alkali metal carbon dioxide electrochemical system for energy storage and/or conversion of carbon dioxide to oxygen  

NASA Technical Reports Server (NTRS)

An alkali metal, such as lithium, is the anodic reactant; carbon dioxide or a mixture of carbon dioxide and carbon monoxide is the cathodic reactant; and carbonate of the alkali metal is the electrolyte in an electrochemical cell for the storage and delivery of electrical energy. Additionally, alkali metal-carbon dioxide battery systems include a plurality of such electrochemical cells. Gold is a preferred catalyst for reducing the carbon dioxide at the cathode. The fuel cell of the invention produces electrochemical energy through the use of an anodic reactant which is extremely energetic and light, and a cathodic reactant which can be extracted from its environment and therefore exacts no transportation penalty. The invention is, therefore, especially useful in extraterrestrial environments.

Hagedorn, Norman H. (inventor)

1993-01-01

357

Carbon dioxide warming of the early Earth  

NASA Technical Reports Server (NTRS)

Svante Arrhenius' research in atmospheric physics extended beyond the recent past and the near future states of the Earth, which today are at the center of sociopolitical attention. His plan encompassed all of the physical phenomena known at the time to relate to the formation and evolution of stars and planets. His two-volume textbook on cosmic physics is a comprehensive synopsis of the field. The inquiry into the possible cause of the ice ages and the theory of selective wavelength filter control led Arrhenius to consider the surface states of the other terrestrial planets, and of the ancient Earth before it had been modified by the emergence of life. The rapid escape of hydrogen and the equilibration with igneous rocks required that carbon in the early atmosphere prevailed mainly in oxidized form as carbon dioxide, together with other photoactive gases exerting a greenhouse effect orders of magnitude larger than in our present atmosphere. This effect, together with the ensuing chemical processes, would have set the conditions for life to evolve on our planet, seeded from spores spreading through an infinite Universe, and propelled, as Arrhenius thought, by stellar radiation pressure.

Arrhenius, G.

1997-01-01

358

Carbon ion pump for removal of carbon dioxide from combustion gas and other gas mixtures  

DOEpatents

A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

Aines, Roger D. (Livermore, CA) [Livermore, CA; Bourcier, William L. (Livermore, CA) [Livermore, CA

2010-11-09

359

Atmospheric Trace Gases, Carbon Isotopes, Radionuclides, and Aerosols: Atmospheric Carbon Dioxide Data from the Carbon Dioxide Information Analysis Center (CDIAC)  

DOE Data Explorer

CDIAC products include numeric data packages, publications, trend data, atlases, models, etc. and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Some of the collections may also be included in the CDIAC publication titled Trends Online: A Compendium of Global Change Data. Most datasets, many with numerous data files, are free to download from CDIAC's ftp area. Information related to atmospheric carbon dioxide data includes: Atmospheric Carbon Dioxide and Carbon Isotopes Atmospheric carbon dioxide records from Mauna Loa, Hawaii Monthly atmospheric CO2 mixing ratios and other data from the NOAA/CMDL continuous monitoring network Data from the CSIRO GASLAB Flask Sampling Network Atmospheric CO2 records from continuous measurements at Jubany Station, Antarctica and from 10 sites in the SIO air sampling network Historical data from the extended Vostok ice core (2003) and the Siple Station ice core (1997) Historical records from the Law Dome DE08, DE08-2, and DSS ice cores (1998) AmeriFlux Carbon Dioxide, Water Vapor, and Energy Balance Measurements Data from the Canadian Background Air Pollution Monitoring Network Flask Samples from at U.S.S.R.-Operated Sites (1991) The CISIRO (Australia) Monitoring Program from Aircraft for 1972-1981 CO2 Concentrations in Surface Water and the Atmosphere during 1986-1989 NOAA/PMEL Cruises in the Pacific and Indian Oceans Surface Water and Atmospheric CO2 and Nitrous Oxide Observations by Shipboard Automated Gas Chromatography: Results from Expeditions Between 1977 and 1990 (1992) IPCC Working Group 1, 1994: Modeling Results Relating Future Atmospheric CO2 Concentrations to Industrial Emissions (1995). New datasets are added when available to the category of atmospheric carbon dioxide.

360

Field results from 3 campaigns to validate the performance of the Miniaturized Laser Heterodyne Radiometer (mini-LHR) for measuring carbon dioxide and methane in the atmospheric column  

NASA Astrophysics Data System (ADS)

We present mini-LHR measurements of column CO2 and CH4 from our recent field campaign at Mauna Loa Observatory (MLO), HI in May 2013 as well as column CO2 measurements from Castle Airport in Merced, CA during the ASCENDS DC-8 campaign in February 2013, and column CO2 measurements made at the NOAA LEF/TCCON (Total Column Carbon Observing Network) site in Park Falls, WI in September 2012. The mini-LHR was completely automated at the MLO location and operates in tandem with an AERONET sun photometer and measures CO2 and CH4 every 15 minutes during daylight hours in clear sky conditions. Laser heterodyne radiometry has been an established receiver technique since the 1970s and has been used to measure a range of atmospheric gases such as ozone, water vapor, methane, ammonia, chlorine monoxide, and nitrous oxide. The mini-LHR is a passive variation on this technique that uses sunlight as the light source to measure absorption of CO2 and CH4 in the infrared. In this instrument, sunlight is collected with collimation optics mounted to the AERONET sun tracker and superimposed with laser light in a single mode fiber coupler. The signals are mixed in a fast photoreceiver (InGaAs detector), and the RF (radio frequency) beat signal is extracted. Changes in concentration of the trace gas are realized through analyzing changes in the beat frequency amplitude. Miniaturization was made possible through the use of smaller distributive feedback (DFB) lasers and related fiber optic components that have recently become commercially available and inexpensive through progress in the telecommunications industry. In addition to the complementary aerosol optical depth measurement, tandem operation with AERONET provides a clear pathway for the mini-LHR to be expanded into a global monitoring network. AERONET has more than 450 instruments worldwide and offers coverage in key arctic regions (not covered by OCO-2) where accelerated warming due to the release of CO2 and CH4 from thawing tundra and permafrost is a concern. A mini-LHR global ground network can also provide an uninterrupted data record that will both bridge gaps in data sets and offer validation for key flight missions such as OCO-2, OCO-3, and ASCENDS. Currently, the only ground global network that routinely measures multiple greenhouse gases in the atmospheric column is TCCON with 18 operational sites worldwide and two in the US. Cost and size of TCCON installations will limit the potential for expansion. We offer a low-cost (<$30K/unit) solution to supplement these measurements.

Wilson, E. L.; Clarke, G. B.; Melroy, H.; Miller, J. H.; Allan, G. R.; McLinden, M. L.; Ott, L.; Holben, B. N.

2013-12-01

361

Membranes for separation of carbon dioxide  

DOEpatents

Methods for separating carbon dioxide from a fluid stream at a temperature higher than about 200.degree. C. with selectivity higher than Knudsen diffusion selectivity include contacting a porous membrane with the fluid stream to preferentially transport carbon dioxide. The porous membrane includes a porous support and a continuous porous separation layer disposed on a surface of the porous support and extending between the fluid stream and the porous support layer. The porous support comprises alumina, silica, zirconia, stabilized zirconia, stainless steel, titanium, nickel-based alloys, aluminum-based alloys, zirconium-based alloys or a combination thereof. Median pore size of the porous separation layer is less than about 10 nm, and the porous separation layer comprises titania, MgO, CaO, SrO, BaO, La.sub.2O.sub.3, CeO.sub.2, HfO.sub.2, Y.sub.2O.sub.3, VO.sub.z, NbO.sub.z, TaO.sub.z, ATiO.sub.3, AZrO.sub.3, AAl.sub.2O.sub.4, A.sup.1FeO.sub.3, A.sup.1MnO.sub.3, A.sup.1CoO.sub.3, A.sup.1NiO.sub.3, A.sup.2HfO.sub.3, A.sup.3 CeO.sub.3, Li.sub.2ZrO.sub.3, Li.sub.2SiO.sub.3, Li.sub.2TiO.sub.3, Li.sub.2HfO.sub.3, A.sup.4N.sup.1.sub.yO.sub.z, Y.sub.xN.sup.1.sub.yO.sub.z, La.sub.xN.sup.1.sub.yO.sub.z, HfN.sup.2.sub.yO.sub.z, or a combination thereof; wherein A is La, Mg, Ca, Sr or Ba; A.sup.1 is La, Ca, Sr or Ba; A.sup.2 is Ca, Sr or Ba; A.sup.3 is Sr or Ba; A.sup.4 is Mg, Ca, Sr, Ba, Ti or Zr; N.sup.1 is V, Nb, Ta, Cr, Mo, W, Mn, Si or Ge; N.sup.2 is V, Mo, W or Si; x is 1 or 2; y ranges from 1 to 3; and z ranges from 2 to 7.

Ku, Anthony Yu-Chung (Rexford, NY); Ruud, James Anthony (Delmar, NY); Ramaswamy, Vidya (Niskayuna, NY); Willson, Patrick Daniel (Latham, NY); Gao, Yan (Niskayuna, NY)

2011-03-01

362

REACTION OF ACTIVATED CARBON WITH AQUEOUS CHLORINE AND CHLORINE DIOXIDE  

EPA Science Inventory

The objective of this research was to determine whether aqueous chlorine and chlorine dioxide react with activated carbon, or with compounds adsorbed on activated carbon, to produce compounds that would not form in the absence of activated carbon. The experimental conditions were...

363

The oxygen and carbon dioxide balance in the earth's atmosphere  

NASA Technical Reports Server (NTRS)

The oxygen-carbon dioxide cycle is described in detail, and steps which are sensitive to perturbation or instability are identified. About half of the carbon dioxide consumption each year in photosynthesis occurs in the oceans. Phytoplankton, which are the primary producers, have been shown to assimilate insecticides and herbicides. The impact of such materials on phytoplankton photosynthesis, both direct and as the indirect result of detrimental effects higher up in the food chain, cannot be assessed. Net oxygen production is very small in comparison with the total production and occurs almost exclusively in a few ocean areas with anoxic bottom conditions and in peat-forming marshes which are sensitive to anthropogenic disturbances. The carbon dioxide content of the atmosphere is increasing at a relatively rapid rate as the result of fossil fuel combustion. Increases in photosynthesis as the result of the hothouse effect may in turn reduce the carbon dioxide content of the atmosphere, leading to global cooling.

Johnson, F. S.

1975-01-01

364

Allowable Exposure Limits for Carbon Dioxide during Extravehicular Activity.  

National Technical Information Service (NTIS)

The intent was to review the research pertaining to human exposure to carbon dioxide (CO2) and to recommend allowable exposure limits for extravehicular activity (EVA). Respiratory, renal, and gastrointestinal systems may be adversely affected by chronic ...

A. J. Seter

1993-01-01

365

Hiilidioksiditoimikunnan mietintoe. (Report of the carbon dioxide commission).  

National Technical Information Service (NTIS)

The Commission was entrusted with investigating alternative strategies and measures for limiting and reducing the emissions of carbon dioxide and other greenhouse gases. It was to study both technical and structural means of reducing these emissions. The ...

J. Routti

1991-01-01

366

Plants Can't Do without Carbon Dioxide.  

ERIC Educational Resources Information Center

Describes an experiment to induce carbon dioxide deficiency to demonstrate its effects on plant growth. Suggests further studies to examine respiration by soil microbes and the effects of relative humidity, other gases, and air pollution on plant growth. (MDH)

Hershey, David R.

1992-01-01

367

Role of Carbon Dioxide in Inert Gas Narcosis.  

National Technical Information Service (NTIS)

The role of carbon dioxide and oxygen in high pressure narcosis was studied by exposing animals to hyperbaric conditions while maintaining them normoxic and normocapnic. Chickens were the experimental animals. Heated, humidified gas entered the lung via a...

H. S. Weiss

1977-01-01

368

Role of Carbon Dioxide in Inert Gas Narcosis.  

National Technical Information Service (NTIS)

The role of carbon dioxide and oxygen in high pressure narcosis was studied by exposing animals to hyperbaric conditions while maintaining them normoxic and normocapnic. Chickens were the experimental animal used. The unanaesthetized restrained birds were...

H. S. Weiss L. W. Torley

1975-01-01

369

Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures  

DOEpatents

A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

Aines, Roger D.; Bourcier, William L.; Viani, Brian

2013-01-29

370

Effect of helium in helium headspace carbon dioxide cylinders on packed-column supercritical fluid chromatography.  

PubMed

Supercritical fluid chromatography of PAHs was performed with pure carbon dioxide and helium headspace carbon dioxide at various cylinder fill levels. The retention times of the PAHs increased when helium headspace carbon dioxide was used as a carrier fluid relative to pure carbon dioxide. The increased retention times were affected by the level of the liquid phase present in the helium headspace carbon dioxide cylinder. As more liquid phase was removed from the cylinder, the effect of helium on the solvating power of CO(2) was reduced because the relative amount of helium dissolved in the liquid phase decreased. Furthermore, the effect of helium headspace carbon dioxide was investigated with methanol-modified carbon dioxide mobile phases for the analysis of steroids. We observed that the relative solubility of helium in carbon dioxide resulted in longer retention times when compared to pure carbon dioxide as the liquid level of carbon dioxide decreased. PMID:21619186

Leichter, E; Strode, J T; Taylor, L T; Schweighardt, F K

1996-03-01

371

Decorating catalytic palladium nanoparticles on carbon nanotubes in supercritical carbon dioxide  

SciTech Connect

Hydrogen reduction of a Pd(II)-b-diketone precursor in supercritical carbon dioxide produces palladium nanoparticles on multi-walled carbon nanotubes that exhibit promising catalytic properties for hydrogenation of olefins in carbon dioxide as well as electro-reduction of oxygen in fuel cell applications.

Ye, Xiang-Rong; Lin, Yuehe; Wai, C M.

2003-02-25

372

Effect of carbon dioxide on fuel stability under storage conditions  

Microsoft Academic Search

1.Carbon dioxide, when used as an inert gas medium for filling the free space in tanks and reservoirs, limits the sediment formation, wards off the formation of oxidation products and existent gum, and stabilizes the acid number and cloud point of the fuel.2.The favorable stabilizing effect of carbon dioxide on fuel oxidation in storage is retained at gas-phase CO2 concentrations

V. N. Zrelov; V. M. Shagin; N. V. Avdeev; T. S. Merzlova; N. A. Afanas'eva; V. V. Bulavin

1973-01-01

373

Rapid determination of carbon dioxide in silicate rocks  

USGS Publications Warehouse

In the development of rapid methods for silicate rock analysis, a simpler and faster means was needed for the determination of carbon dioxide than the conventional "train" procedures. With the method presented here, which involves measurement of the volume of carbon dioxide evolved, the time required for a determination is about 5 minutes per sample. It provides a saving of 30 to 40 minutes for each determination without significant loss of accuracy.

Shapiro, L.; Brannock, W. W.

1955-01-01

374

Measurements of Surface Ocean Carbon Dioxide Partial Pressure During WOCE  

Microsoft Academic Search

All of the technical goals of the World Ocean Circulation Experiment (WOCE) field program which were supported under the Department of Energy research grant ''Measurements of Surface Ocean Carbon Dioxide Partial Pressure During WOCE'' (DE-FG03-90ER60981) have been met. This has included the measurement of the partial pressures of carbon dioxide (C0) and nitrous oxide (NO) in both the surface ocean

1998-01-01

375

Precipitation of food protein using high pressure carbon dioxide  

Microsoft Academic Search

High pressure carbon dioxide has been applied to precipitate soy protein. The method is suitable for effective precipitation of soy proteins and prevents local pH overshoot, which usually occurs in case of using mineral acids for the precipitation processes. It was possible to achieve 68.3wt% of soy protein precipitate using 30bars of pressurized carbon dioxide, at pH of 5.60 and

Nawal Khorshid; M. M. Farid

2007-01-01

376

Carbon dioxide in the ocean surface: The homogeneous buffer factor  

USGS Publications Warehouse

The amount of carbon dioxide that can be dissolved in surface seawater depends at least partially on the homogeneous buffer factor, which is a mathematical function of the chemical equilibrium conditions among the various dissolved inorganic species. Because these equilibria are well known, the homogeneous buffer factor is well known. Natural spatial variations depend very systematically on sea surface temperatures, and do not contribute significantly to uncertainties in the present or future carbon dioxide budget. Copyright ?? 1979 AAAS.

Sundquist, E. T.; Plummer, L. N.; Wigley, T. M. L.

1979-01-01

377

Supercritical carbon dioxide extraction and deacidification of rice bran oil  

Microsoft Academic Search

This study examined pilot-scale extraction and lab-scale deacidification of rice bran oil by using supercritical carbon dioxide (SC-CO2). Two purest gamma-oryzanols (?-oryzanols) (>98wt%) were initially obtained by preparative reverse-phase high-performance liquid chromatography. Supercritical carbon dioxide extraction at 300bar and 313K from 1.03kg powdered rice bran indicated a total yield of oil of 15.7% with a free fatty acids content of

Chao-Rui Chen; Chih-Hung Wang; Ling-Ya Wang; Zih-Hao Hong; Shuo-Hsiu Chen; Wai-Jane Ho; Chieh-Ming J. Chang

2008-01-01

378

Feasibility of Metalworking Fluids Delivered in Supercritical Carbon Dioxide  

Microsoft Academic Search

This paper presents a new method to lubricate, cool, and evacuate chips in metalworking operations using supercritical carbon dioxide (scCO2). Water-based and straight oil metalworking fluids (MWFs) are currently being used to perform these functions even though they are characterized by high economic, occupational health, and environmental costs. Carbon dioxide above its critical temperature and pressure is a finely tunable

Andres F. Clarens; Kim F. Hayes; Steven J. Skerlos

2006-01-01

379

Methanolysis of seed oils in flowing supercritical carbon dioxide  

Microsoft Academic Search

The direct methanolysis of triglycerides in flowing supercritical carbon dioxide by an immobilized lipase is described. The\\u000a reaction system consists of two syringe pumps for substrate addition and another two syringe pumps for delivering CO2 at 24.1 MPa. Corn oil is pumped into the carbon dioxide stream at a rate of 4 ?L\\/min, and methanol is pumped at 5 ?L\\/min

Michael A. Jackson; Jerry W. King

1996-01-01

380

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

Microsoft Academic Search

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation,

William K. OConnor; David C. Dahlin; David N. Nilsen; Richard P. Walters; Paul C. Turner

2000-01-01

381

Acute carbon dioxide avoidance in Caenorhabditis elegans.  

PubMed

Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO2 avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO2 responsiveness via the insulin and TGFbeta signaling pathways. CO2 response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO2 avoidance. Our results demonstrate that C. elegans senses and responds to CO2 using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm. PMID:18524955

Hallem, Elissa A; Sternberg, Paul W

2008-06-10

382

Miniaturized Amperometric Solid Electrolyte Carbon Dioxide Sensors  

NASA Technical Reports Server (NTRS)

A miniaturized electrochemical carbon dioxide (CO2) sensor using Na3Z r2Si2PO12 (NASICON) as a solid electrolyte has been fabricated and de monstrated. Microfabrication techniques were used for sensor fabricat ion to yield a sensing area around 1.0 mm x 1.1 mm. The NASICON solid electrolyte and the Na2CO3/BaCO3 (1:1.7 molar ratio) auxiliary elect rolyte were deposited by sputtering in between and on top of the inte rdigitated finger-shaped platinum electrodes. This structure maximize s the length of the three-phase boundary (electrode, solid electrolyt e, and auxiliary electrolyte), which is critical for gas sensing. The robust CO2 sensor operated up to 600 C in an amperometric mode and a ttempts were made to optimize sensor operating parameters. Concentrat ions of CO2 between 0.02% and 4% were detected and the overall sensor performance was evaluated. Linear response of sensor current output to ln[CO2 concentration] ranging from 0.02% to 1% was achieved.

Hunter, G. W.; Xu, J. C.; Liu, C. C.; Hammond, J. W.; Ward, B.; Lukco, D.; Lampard, P.; Artale, M.; Androjna, D.

2006-01-01

383

Euthanasia of neonatal mice with carbon dioxide  

USGS Publications Warehouse

Exposure to carbon dioxide (CO2) is the most prevalent method used to euthanize rodents in biomedical research. The purpose of this study was to determine the time of CO2 exposure required to euthanize neonatal mice (0 to 10 days old). Multiple groups of mice were exposed to 100% CO 2 for time periods between 5 and 60 min. Mice were placed in room air for 10 or 20 min after CO2 exposure, to allow for the chance of recovery. If mice recovered at one time point, a longer exposure was examined. Inbred and outbred mice were compared. Results of the study indicated that time to death varied with the age of the animals and could be as long as 50 min on the day of birth and differed between inbred and outbred mice. Institutions euthanizing neonatal mice with CO2 may wish to adjust their CO 2 exposure time periods according the age of the mice and their genetic background. Copyright 2005 by the American Association for Laboratory Animal Science.

Pritchett, K.; Corrow, D.; Stockwell, J.; Smith, A.

2005-01-01

384

Rat aversion to isoflurane versus carbon dioxide  

PubMed Central

Some experts suggest that sedation of laboratory rodents with isoflurane before euthanasia with carbon dioxide (CO2) is a humane alternative to euthanasia with CO2 alone, but little research has compared aversion with these agents. Albino rats were tested in a lightdark box where they had the choice between remaining in a dark compartment filling with isoflurane or CO2, or escaping to a lit compartment. Experiment 1 validated the procedure by confirming that rats responded to agent and light intensity. In experiment 2, 9/16 and 0/16 rats remained in the dark compartment until recumbent when initially exposed to isoflurane and CO2, respectively. In experiment 3, more rats remained in the dark compartment until recumbent during initial (10/16) versus re-exposure (1/16) to isoflurane. These results indicate that initial exposure to CO2 is more aversive than isoflurane, and that re-exposure to isoflurane is more aversive than initial exposure. We conclude that sedation with isoflurane is a refinement over euthanasia with CO2 alone for rats that have not been previously exposed to inhalant anaesthetics.

Wong, Devina; Makowska, I. Joanna; Weary, Daniel M.

2013-01-01

385

Carbon dioxide dynamics in an artificial ecosystem  

NASA Astrophysics Data System (ADS)

An experimental artificial ecosystem was established as a tool to understand the behavior of closed ecosystem and to develop the technology for a future bioregenerative life support system for lunar or planetary exploration. Total effective volume of the system is 0.7 m3 . It consists of a higher plant chamber, an animal chamber and a photo-bioreactor which cultivated lettuce (Lactuca sativa L.), silkworm (Bombyx Mori L.) and microalgae (Chlorella), respectively. For uniform and sustained observations, lettuce and silkworms was cultivated using sequential cultivation method, and microalgae using continuous culture. Four researchers took turns breathing the system air through a tube for brief periods every few hours. A mathematic model, simulating the carbon dioxide dynamics was developed. The main biological parameters concerning photosynthesis of lettuce and microalgae, respiration of silkworms and human were validated by the experimental data. The model described the respiratory relationship between autotrophic and heterotrophic compartments. A control strategy was proposed as a tool for the atmosphere management of the artificial ecosystem.

Hu, Enzhu; Hu, Dawei; Tong, Ling; Li, Ming; Fu, Yuming; He, Wenting; Liu, Hong

386

Carbon dioxide sequestration by direct aqueous mineral carbonation  

SciTech Connect

Carbon dioxide sequestration by an ex-situ, direct aqueous mineral carbonation process has been investigated over the past two years. This process was conceived to minimize the steps in the conversion of gaseous CO2 to a stable solid. This meant combining two separate reactions, mineral dissolution and carbonate precipitation, into a single unit operation. It was recognized that the conditions favorable for one of these reactions could be detrimental to the other. However, the benefits for a combined aqueous process, in process efficiency and ultimately economics, justified the investigation. The process utilizes a slurry of water, dissolved CO2, and a magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. These minerals were selected as the reactants of choice for two reasons: (1) significant abundance in nature; and (2) high molar ratio of the alkaline earth oxides (CaO, MgO) within the minerals. Because it is the alkaline earth oxide that combines with CO2 to form the solid carbonate, those minerals with the highest ratio of these oxides are most favored. Optimum results have been achieved using heat pretreated serpentine feed material, sodium bicarbonate and sodium chloride additions to the solution, and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Future studies are intended to investigate various mineral pretreatment options, the carbonation solution characteristics, alternative reactants, scale-up to a continuous process, geochemical modeling, and process economics.

O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

2000-01-01

387

Cycling Carbon: Seeing How Plants Use Carbon Dioxide in the Lab  

NSDL National Science Digital Library

This activity discusses the nature of carbon, the different types of compounds in which it exists (e.g. charcoal, glucose, carbon dioxide), the biochemical reactions in which it takes part (photosynthesis and respiration), the range of processes that carbon and carbon compounds are involved in on Earth, and how these link together to form the carbon cycle. This activity demonstrates the uptake of carbon dioxide by plants, using Elodea as the example. Students are reminded that Elodea is a pond plant that lives below the water surface and thus extracts dissolved carbon dioxide from the water rather than directly from the atmosphere as terrestrial plants do. The students will discover that the carbon exchange between living things and the atmosphere mostly happens through photosynthesis and respiration. During the growing season leaves take up carbon dioxide and carbon is then stored in the living biomass.

388

Fixation and activation of carbon dioxide on aluminum porphyrin. Catalytic formation of carbamic ester from carbon dioxide, amine, and epoxide  

SciTech Connect

Carbon dioxide is trapped by (5,10,15,20-tetraphenylporphinato) aluminum acetate in the presence of a secondary amine in the form of an aluminum carbamate on the opposite side to the acetate group with respect to the porphyrin plane. Carbon dioxide thus trapped by aluminum porphyrin is activated enough to undergo a catalytic reaction involving secondary amine and epoxide to afford dialkylcarbamic ester under atmospheric pressure at room temperature. 15 references, 2 figures, 2 tables.

Kojima, F.; Aida, T.; Inoue, S.

1986-02-05

389

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

This report describes research conducted between April 1, 2004 and June 30, 2004 on the preparation and use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Support materials and supported sorbents were prepared by spray drying. Sorbents consisting of 20 to 50% sodium carbonate on a ceramic support were prepared by spray drying in batches of approximately 300 grams. The supported sorbents exhibited greater carbon dioxide capture rates than unsupported calcined sodium bicarbonate in laboratory tests. Preliminary process design and cost estimation for a retrofit application suggested that costs of a dry regenerable sodium carbonate-based process could be lower than those of a monoethanolamine absorption system. In both cases, the greatest part of the process costs come from power plant output reductions due to parasitic consumption of steam for recovery of carbon dioxide from the capture medium.

David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Thomas Nelson

2004-07-01

390

Urban carbon dioxide in Portland, Oregon  

NASA Astrophysics Data System (ADS)

Ambient concentrations of atmospheric carbon dioxide (CO2) are reported for the Portland, Oregon (USA) metropolitan region since late July, 2009. Three stationary locations were established: a downtown location on the campus of Portland State University; a residential site in southeast Portland; and a rural station on Sauvie Island, located ~30km northwest of Portland in the Columbia River Gorge. Continuous measurements of CO2 at the sites average 400-410ppm and show considerable variability due to CO2 sources, sinks and meteorological drivers of ventilation. Within this variability, a marked 20-30ppm diurnal cycle is observed due to photosynthetic activity and variations in the planetary boundary layer. In-city CO2 concentrations are on average enhanced by 5-6ppm over the Sauvie Island site during upgorge wind conditions, a difference which is greatest in the afternoon. Measurements of the 13C/12C ratio of CO2 in downtown Portland are significantly depleted in 13C relative to 12C compared with background air and suggest that regional CO2 is dominated by petroleum sources (70-80%). High degrees of relationship between CO2 variability and primary air pollutants CO and NO (r2=0.70 to 0.80), measured by the Oregon Department of Environmental Quality at the Southeast Portland location, corroborate this finding and illustrate the importance of traffic emissions on elevated ambient CO2 concentrations. In addition to CO2 at the fixed sites, measurements of street-level CO2 concentrations were obtained using a mobile instrument mounted in a bike trailer. Results from these field data show relatively homogenous CO2 concentrations throughout residential Portland neighborhoods with significant enhancements in CO2 on busy roadways or near areas of traffic congestion.

Bostrom, G. A.; Brooks, M.; Rice, A. L.

2010-12-01

391

The Headache of Carbon Dioxide Exposures  

NASA Technical Reports Server (NTRS)

Carbon dioxide (CO2), a natural product of human metabolism, accumulates quickly in sealed environments when humans are present, and can induce headaches, among other symptoms. Major resources are expended to control CO2 levels to concentrations that are tolerable to the crews of spacecraft and submersible craft. It is not practical to control CO2 levels to those found in the ambient environment on earth. As NASA looks ahead to long-duration missions conducted far from earth, difficult issues arise related to the management and effects of human exposure to CO2. One is the problem of pockets of CO2 in the habitat caused by excess generation of the gas in one location without a mechanism to purge the area with fresh air. This results in the crew rebreathing CO2 from their exhaled breath, exposing them to a much higher concentration of CO2 than whole-module measurements would suggest. Another issue is the potential increased sensitivity to CO2 in microgravity. For example, based on anecdotal information, it appears that space crews may be more susceptible than submarine crews to some of the subtle, yet adverse effects of CO2 exposure. Another issue, not unique to spaceflight, is the possibility of inter-individual differences in the susceptibility of crewmembers to CO2 exposure. Again, anecdotal reports from the International Space Station (ISS) crews suggest that certain individuals may experience a greater susceptibility. The implications associated with these issues are extremely important as NASA sets CO2 exposure limits that protect the crew from this compound s subtle adverse effects, without causing an unwarranted expenditure of resources to scrub CO2 from the habitat atmosphere.

James, John T.

2007-01-01

392

Carbon dioxide catastrophes: Past and future menace  

NASA Technical Reports Server (NTRS)

Carbon dioxide is important in its role as coupler of the terrestrial biosphere to inorganic chemical processes and as the principal greenhouse gas controlling Earth's surface temperature. The hypothesis that atmospheric CO2 levels have diminished with time, with the resulting cooling effect offsetting an increase in the solar constant, seems firmly established, and it is shown that feedback mechanisms exist which can maintain the terrestrial surface in a relatively narrow temperature range over geological time. Of the factors involved in such CO2 variation, the oceanic reservoir appears the most important. Surface waters are probably in approximate equilibrium with regard to CO2 exchange with the ambient atmosphere in most regions, but data from deep-ocean water sampling indicates that such waters are somewhat undersaturated in the sense that they would tend to absorb CO2 from the atmosphere if brought to the surface without change in composition or temperature. If major impacts into the ocean can result in loss of a substantial portion of the atmospheric CO2 reservoir, then any such future event could imperil the continuation of most higher forms of life on Earth. The most likely candidate for an inverse Nyos global event in previous Earth history is the Cretaceous-Tertiary terminal extinction event. The Cretaceous was characterized by warm, equable temperatures presumably indicative of relatively high CO2 levels and an intense greenhouse heating. Cooling of the oceans in absence of massive transfer of CO2 to the oceanic reservoir in itself would promote a condition of CO2 undersaturation in abyssal waters, and this is made even more extreme by the pattern of ocean water circulation. It is possible to envision a situation in which deep ocean waters were at least occasionally profoundly undersaturated with regard to CO2. Turnover of a major fraction of such an ocean would then remove, on a very short time scale, as much as 90 percent of the atmospheric CO2 inventory.

Baur, Mario E.

1988-01-01

393

Removal of organic impurities from liquid carbon dioxide  

NASA Astrophysics Data System (ADS)

The use of a high velocity stream of carbon dioxide snowflakes to clean large optics is well known, and has gained widespread acceptance in the astronomical community as a telescope maintenance technique. Ultimately, however, the success of carbon dioxide snow cleaning depends on the availability of high purity carbon dioxide. The higher the purity of the carbon dioxide, the longer will be the time interval between required mirror washings. The highest grades of commercially produced liquid carbon dioxide are often not available in the more remote regions of the world - such as where major astronomical observatories are often located. Furthermore, the purity of even the highest grades of carbon dioxide are only nominal, and wide variations are known to occur from tank to tank. Occasionally, visible deposits of organic impurities are left behind during cleaning with carbon dioxide that is believed to be 99.999% pure. A zeolite molecular sieve based filtration system has proven to be very effective in removing these organic impurities. A zeolite is a complex alumino-silicate. One example has an empirical formula of Na2O(Al2O3)(SiO2)2yH2O, where y=0 to 8. The zeolites have an open crystal structure and are capable of trapping impurities like 8-methylheptadecane (an oil) and 2,6-octadine-1-ol,3,7- dimethyl-,(E)- (a fatty acid). In fact, a zeolite can trap 29.5% of its own weight in SAE 20 lubricant at 25 degree(s)C. After filtration of liquid CO2 through zeolites, the concentration of measured impurities was below the detection limit for state-of-the-art gas chromatography systems.

Zito, Richard R.

2002-09-01

394

Carbon Dioxide Effects Research and Assessment Program. Carbon Dioxide Research Progress Report, fiscal year 1979  

SciTech Connect

Research on the global carbon cycle and the effects of increased carbon dioxide on the global climate system is reported. Environmental and societal effects related to CO/sub 2/ and environmental control technology for CO/sub 2/ are also discussed. Lists of research projects and reports and publications of the Carbon Dioxide and Climate Research Program are included. An expanded CO/sub 2/ monitoring network is providing increased coverage for interpretation of patterns of sources and sinks seasonal variability, and documentation of the global growth of CO/sub 2/. Modeling studies emphasized that knowledge of the transport and mixing of surface ocean waters is important in understanding deep oceanic circulation. Initial studies in the equatorial Pacific are helping quantify estimates of the amount of outgassing CO/sub 2/ from tropical waters. During fiscal year 1979, there was a substantial increase in appreciation of the role of the ocean in controlling not only atmospheric CO/sub 2/ concentrations but also the climatic response to changes in concentration. Model simulations of the effect of doubled CO/sub 2/ concentration carried out with fixed ocean temperatures a situation that is possible during perhaps the next 20 years, showed relatively small summer heating over land areas. On the other hand, simulations in which the oceanic temperatures could come into instantaneous equilibrium with atmospheric conditions continued to show global temperature increases of 3 +- 1.5/sup 0/C, accentuated at high latitudes. To improve understanding of possible regional climate changes, there were increased efforts to reconstruct regional climatic patterns prevailing during past warm periods that might serve as analogs of future climatic conditions. Particular attention was directed to the climates of the United States and other countries bordering the North Atlantic Ocean during the warm period 5000 to 7000 years ago.

Dahlman, R.C.; Gross, T.; Machta, L.; Elliott, W.; MacCracken, M.

1980-04-01

395

Vegetation Response to Carbon Dioxide and Climate: Data from the Carbon Dioxide Information Analysis Center (CDIAC)  

DOE Data Explorer

CDIAC products are indexed and searchable through a customized interface powered by ORNL's Mercury search engine. Products include numeric data packages, publications, trend data, atlases, and models and can be searched for by subject area, keywords, authors, product numbers, time periods, collection sites, spatial references, etc. Some of the collections may also be included in the CDIAC publication Trends Online: A Compendium of Global Change Data. Most data sets, many with numerous data files, are free to download from CDIAC's ftp area. Information related to vegetation response to carbon dioxide and climate includes: Area and Carbon Content of Sphagnum Since Last Glacial Maximum (2002) (Trends Online) TDE Model Intercomparison Project Data Archive Presentations and abstracts from the recent DOE Terrestrial Science Team Meeting (Argonne National Laboratory, October 29-31, 2001) FACE (Free-Air CO2 Enrichment) Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species Composition, and Growth (2001) Bibliography on CO2 Effects on Vegetation and Ecosystems: 1990-1999 Literature (2000) Direct effects of atmospheric CO2 enrichment on plants and ecosystems: An updated bibliographic data base (1994) A Database of Herbaceous Vegetation Responses to Elevated Atmospheric CO2 (1999) A Database of Woody Vegetation Responses to Elevated Atmospheric CO2 (1999) Forest Responses to Anthropogenic Stress (FORAST) Database (1995) Effects of CO2 and Nitrogen Fertilization on Growth and Nutrient Content of Juvenile Ponderosa Pine (1998) Carbon Dioxide Enrichment: Data on the Response of Cotton to Varying CO2Irrigation, and Nitrogen (1992) Growth and Chemical Responses to CO2 Enrichment Virginia Pine Pinus Virginiana Mill.(1985)

396

Assessing Carbon Dioxide Emissions from Energy Use at a University  

ERIC Educational Resources Information Center

Purpose: The purpose of this paper is to assess the carbon dioxide emissions associated with electric, HVAC, and hot water use from a US university. Design/methodology/approach: First, the total on-campus electrical, natural gas and oil consumption for an entire year was assessed. For each category of energy use, the carbon associated with

Riddell, William; Bhatia, Krishan Kumar; Parisi, Matthew; Foote, Jessica; Imperatore, John, III

2009-01-01

397

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

Microsoft Academic Search

The objective of this project is to develop a simple, inexpensive process to separate CO as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, or ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate

David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

2002-01-01

398

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

Microsoft Academic Search

The objective of this project is to develop a simple, inexpensive process to separate CO as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbent being used in this project is sodium carbonate which is converted to sodium bicarbonate, ''baking soda,'' through reaction with carbon dioxide and water vapor. Sodium bicarbonate is

David A. Green; Brian S. Turk; Raghubir P. Gupta; Douglas P. Harrison; Ya Liang

2001-01-01

399

Mechanisms of Neutralization of Bauxite Residue by Carbon Dioxide  

Microsoft Academic Search

Bauxite residue red mud, an alkaline slurry from alumina refining, is produced in large volumes and disposed of in large surface impoundments. The objectives of this study were to measure the extent of neutralization of bauxite residue by carbon dioxide as a function of CO2 partial pressure and to determine the geochemical reactions responsible for carbon sequestration. Bauxite residue was

Sameer Khaitan; David A. Dzombak

2009-01-01

400

Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide  

DOEpatents

A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

Rathke, J.W.; Klingler, R.J.

1993-03-30

401

Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide  

DOEpatents

A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

Rathke, Jerome W. (Lockport, IL); Klingler, Robert J. (Westmount, IL)

1993-01-01

402

Electroreduction of carbon dioxide in aqueous solutions at metal electrodes  

SciTech Connect

The quantities of carbon stored in the form of atmospheric carbon dioxide, CO{sub 2} in the hydrosphere and carbonates in the terrestrial environment substantially exceed those of fossil fuels. In spite of this the industrial use of carbon dioxide as a source of chemical carbon is presently limited to preparation of urea and certain carboxylic acids as well as organic carbonates and polycarbonates. However, the situation is expected to change in the future, if effective catalytic systems allowing to activate carbon dioxide will become available. In this connection, the electrochemical reduction of CO{sub 2}, requiring only an additional input of water and electrical energy, appears as an attractive possibility. For more than 100 years formic acid and formates of alkali metals were considered as the only significant products of the electroreduction of carbon dioxide in aqueous solutions. The highest current efficiencies, exceeding 90 %, were obtained either with mercury or with amalgam electrodes. The only comprehensive study regarding kinetics of CO{sub 2} reduction in aqueous solution has been performed by Eyring et al. using a mercury cathode. This paper describes electrolysis studies.

Augustynski, J.; Jermann, B.; Kedzierzawski, P. [Univ. of Geneva (Switzerland)

1996-12-31

403

Capturing carbon dioxide as a polymer from natural gas.  

PubMed

Natural gas is considered the cleanest and recently the most abundant fossil fuel source, yet when it is extracted from wells, it often contains 10-20?mol% carbon dioxide (20-40?wt%), which is generally vented to the atmosphere. Efforts are underway to contain this carbon dioxide at the well-head using inexpensive and non-corrosive methods. Here we report nucleophilic porous carbons are synthesized from simple and inexpensive carbon-sulphur and carbon-nitrogen precursors. Infrared, Raman and (13)C nuclear magnetic resonance signatures substantiate carbon dioxide fixation by polymerization in the carbon channels to form poly(CO2) under much lower pressures than previously required. This growing chemisorbed sulphur- or nitrogen-atom-initiated poly(CO2) chain further displaces physisorbed hydrocarbon, providing a continuous carbon dioxide selectivity. Once returned to ambient conditions, the poly(CO2) spontaneously depolymerizes, leading to a sorbent that can be easily regenerated without the thermal energy input that is required for traditional sorbents. PMID:24892923

Hwang, Chih-Chau; Tour, Josiah J; Kittrell, Carter; Espinal, Laura; Alemany, Lawrence B; Tour, James M

2014-01-01

404

Supercritical Carbon Dioxide Regeneration of Activated Carbon Loaded with Contaminants from Rocky Mountain Arsenal Well Water.  

National Technical Information Service (NTIS)

The method of supercritical carbon dioxide (SCF CO2) regeneration of granular activated carbon (GAC) loaded with DIMP (diisopropyl methylphosphonate) from Rocky Mountain Arsenal Well (NO. 23-120) water was investigated. A laboratory-based adsorption/regen...

R. M. O'Brien R. P. de Filippi C. E. Smith D. G. Hager

1982-01-01

405

Regeneration of oxygen from carbon dioxide and water.  

NASA Technical Reports Server (NTRS)

In a closed ecological system it is necessary to reclaim most of the oxygen required for breathing from respired carbon dioxide and the remainder from waste water. One of the advanced physicochemical systems being developed for generating oxygen in manned spacecraft is the solid electrolyte-electrolysis system. The solid electrolyte system consists of two basic units, an electrolyzer and a carbon monoxide disproportionator. The electrolyzer can reclaim oxygen from both carbon dioxide and water. Electrolyzer preparation and assembly are discussed together with questions of reactor design and electrolyzer performance data.

Weissbart, J.; Smart, W. H.; Wydeven, T.

1972-01-01

406

What Are the Human-Caused Sources of Carbon Dioxide?  

NSDL National Science Digital Library

This activity presents a digital interactive where students identify anthropogenic sources of carbon dioxide and their relative contribution to carbon enrichment of the atmosphere. Students then obtain a photograph pair of a scene in their community, and identify sources of atmospheric carbon dioxide that did not exist in the earlier photograph. Alternatively, they can interview community members to obtain the same information. This activity is supported by a textbook chapter, How is the Atmosphere Changing?, part of the unit, Climate Change, in Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

407

Economic Effects of Using Carbon Taxes to Reduce Carbon Dioxide Emissions in Major OECD Countries.  

National Technical Information Service (NTIS)

A tax on fossil fuels designed to obtain a 20 percent reduction in emissions of carbon dioxide by the year 2020 would lower output among major OECD nations by 1 to 3 1/2 percent. The tax required to achieve a 20% reduction in emissions of carbon dioxide b...

1992-01-01

408

Hedging Carbon Risk: Protecting Customers and Shareholders from the Financial Risk Associated with Carbon Dioxide Emissions  

SciTech Connect

Utilities and regulators are recognizing the imprudence of assuming that carbon dioxide emissions will not cost anything over the long lifetime of new investments. Several utilities have begun to protect their customers and shareholders from this financial risk by integrating an estimated cost of carbon dioxide emissions into their evaluation of resource options, and selecting the overall least-cost portfolio of resources.

Bokenkamp, Karl; LaFlash, Hal; Singh, Virinder; Bachrach Wang, Devra

2005-07-01

409

Natural Methane and Carbon Dioxide Hydrates in the Earth System  

NASA Astrophysics Data System (ADS)

Both CH4 and CO2 are abundant volatiles in the earth's crust. Methane hydrates occur in permafrost regions and continental slopes of oceans. It is currently estimated that the energy stored in CH4 hydrate reserves totals more than twice the global reserves of all conventional oil, gas, and coal deposits combined. This means that methane hydrate could prove to be a very important source of energy in the future. Pressure versus temperature phase diagrams for methane and carbon dioxide define characteristic stability fields for gas, fluid and hydrates states. Sequestration of carbon dioxide in the earths crust and production of methane hydrate reservoirs are critically dependent on knowledge of the in situ elastic moduli of natural hydrates. The physical properties of simple methane and carbon dioxide hydrates are similar [1]. Our compilation of experimental data confirms high compressional wave velocities and elastic moduli for CH4 and CO2 hydrates and low compressional wave velocities for the fluid and gas phases. As methane and carbon dioxide hydrates are stable over similar pressure-temperature ranges, the two types of hydrates form in similar settings in the earth's crust. For example, temperature and pressure conditions in deepwater marine environments require both CO2 and CH4 to be in hydrate phase. However, not much is known about the origin, distribution and total volume of natural carbon dioxide hydrates stored in the earth's crust. For a number of tectonic/geological settings, CO2-rich fluids from deep crustal reservoirs must be considered: rifted margins, volcanic arcs, deepwater vents [2], mud volcanoes and mud diapirs [3]. Both methane and carbon dioxide hydrates work to cement sea floors in similar ways. Slope failure, a phenomenon usually taken as a hallmark of the presence of methane hydrate, could also be attributed to the existence of carbon dioxide hydrates. Perhaps most critically, many of the estimations of the amounts of methane hydrates are based on seismic imaging. However, since carbon dioxide hydrate can also form gas traps and subsequently bottom simulating reflections (a prime indicator of methane hydrate reserves), we speculate that some of the global estimated methane hydrate may in fact be natural carbon dioxide hydrate. References: [1] Sivaraman, R., Gas TIPS, 9, 4-7, 2003;[2] Sakai, H. et al., Science, 248, 1093-1096, 1990; [3] Mueller, C. et al., World Oil, 222, 60-67, 2001

Research Team; Milkereit, B.

2004-05-01

410

SCORR - supercritical carbon dioxide resist removal.  

SciTech Connect

SCORR, short for supercritical carbon dioxide resist removal, is a new technology that could continue to enable the technological development of photolithography processes in industry. SCORR is based upon the physical properties of supercritical fluids (SCFs). These special properties enable SCFs to remove coatings, residues, and particles froin high-aspect-ratio structures in integrated circuits (ICs). SCORR also eliminates rinsing and drying steps presently used in IC manufacture, thereby eliminating the generation of millions of gallons of water per fab per day. Fabricating integrated circuits relies heavily on photolithography to define the shape and pattern of individual components. Once a single stage of a silicon wafer's topography has been completed, the hardened resist must be removed. Conventional processes generates more waste than any single step in the IC manufacturing process, and the production of a complete IC can involve many photolithography iterations. The cost associated with the treatment and disposal of this waste, as well as employee health and safety considerations, are driving a search for a1 ternative, environmentally benign, cost-effective solutions. In addition, photoresist stripping is confronting finer architectures and higher aspect ratios, as well as new low-k materials that are highly sensitive to post-etch residue. Low-k dielectrics and low-resistivity conductors such as copper are necessary for meeting industry's need for faster and smaller chips. Further, each low-k choice requires different plasma-etching processes, or chemistries, to etch structures into the low-k material; therefore, the nature of the residues can be different. No one product can meet all copper/low-k applications, and existing chemistries are not tunable - or even desirable - for the new processes. We have developed a new process - known as SCORR - that removes photoresist and post-ash, -etch, and -CMP (particulate) residue from semiconductor wafers. As IC feature sizes become smaller, the need for ensuring particle removal will increase. With feature sizes of less than 0.18{micro}m, it will become imperative that all particles greater than about 0.1 micron be removed from the semiconductor wafer. Existing cleaning technologies (such as liquid or high-pressure jet scrubbing) cannot remove particles on the order of 0.1 micron because of surface boundary layer constraints. Because of the low viscosities of supercritical fluids (SCFs), these constraints are virtually eliminated.

Jacobson, G. B. (Gunilla B.); Williams, L. L. (Laurie L.); Hollis, W. K. (William K.); Barton, Jerome C.; Taylor, C. M. (Craig M.)

2002-01-01

411

Water and Carbon Dioxide Adsorption at Olivine Surfaces  

SciTech Connect

Plane-wave density functional theory (DFT) calculations were performed to simulate water and carbon dioxide adsorption at the (010) surface of five olivine minerals, namely, forsterite (Mg2SiO4), calcio-olivine (Ca2SiO4), tephroite (Mn2SiO4), fayalite (Fe2SiO4), and Co-olivine (Co2SiO4). Adsorption energies per water molecule obtained from energy minimizations varied from -78 kJ mol-1 for fayalite to -128 kJ mol-1 for calcio-olivine at sub-monolayer coverage and became less exothermic as coverage increased. In contrast, carbon dioxide adsorption energies at sub-monolayer coverage ranged from -20 kJ mol-1 for fayalite to -59 kJ mol-1 for calcio-olivine. Therefore, the DFT calculations show a strong driving force for carbon dioxide displacement by water at the surface of all olivine minerals in a competitive adsorption scenario. Additionally, adsorption energies for both water and carbon dioxide were found to be more exothermic for the alkaline-earth (AE) olivines than for the transition-metal (TM) olivines and to not correlate with the solvation enthalpies of the corresponding divalent cations. However, a correlation was obtained with the charge of the surface divalent cation indicating that the more ionic character of the AE cations in the olivine structure relative to the TM cations leads to greater interactions with adsorbed water and carbon dioxide molecules at the surface and thus more exothermic adsorption energies for the AE olivines. For calcio-olivine, which exhibits the highest divalent cation charge of the five olivines, ab initio molecular dynamics simulations showed that this effect leads both water and carbon dioxide to react with the surface and form hydroxyl groups and a carbonate-like species, respectively.

Kerisit, Sebastien N.; Bylaska, Eric J.; Felmy, Andrew R.

2013-11-14

412

Model-based estimation of the global carbon budget and its uncertainty from carbon dioxide and carbon isotope records  

Microsoft Academic Search

A global carbon cycle model is used to reconstruct the carbon budget, balancing emissions from fossil fuel and land use with carbon uptake by the oceans, and the terrestrial biosphere. We apply Bayesian statistics to estimate uncertainty of carbon uptake by the oceans and the terrestrial biosphere based on carbon dioxide and carbon isotope records, and prior information on model

Haroon S. Kheshgi; Atul K. Jain; Donald J. Wuebbles

1999-01-01

413

Helium enrichment during convective carbon dioxide dissolution  

NASA Astrophysics Data System (ADS)

Motivated by observed variations of the CO2/He ratios in natural carbon dioxide (CO2) reservoirs, such as the Bravo Dome field in northeastern New Mexico, we have performed laboratory experiments equilibrating gas mixtures containing Helium (He) and CO2 with water, at close to ambient conditions in a closed system. The experimental design allows for continuous measurement of headspace pressure as well as timed interval measurements of the CO2/He ratios and the ?13C value of CO2 in the headspace. Results from three dissolution experiments are reported: 1) pure Helium system, 2) 98% CO2 + 2% Nitrogen system, and 3) 97% CO2 and 3% Helium. Final equilibrated experimental results are compared to theoretical results obtained using Henry's Law relationships. The evolution of the amount of dissolved CO2 computed from gas pressure and gas compositions are in good agreement with Henry's Law relationships. For example, the CO2 + N2 system was initially pressurized with pure CO2 to 1323 mbar and after six days it equilibrated to a measured headspace pressure of 596 mbar. This compares very well with a calculated equilibrium headspace pressure of 592 mbar for this system. The CO2 + He system was pressurized to 1398 mbar CO2 and after six days equilibrated to a measured headspace pressure of 397 mbar. This measured pressure is slightly higher than the predicted equilibrated headspace pressure of 341 mbar, indicating a possible leak in the system during this particular experiment. In both experiments the initial pH of the water was 9.3 and the final equilibrated pH was 5.4. The ?13C value of equilibrated headspace CO2 was within 0.25 of its starting ?13C value, demonstrating insignificant carbon isotope fractionation at low pH. Measured Helium/ CO2 ratios throughout the CO2+Helium experiment preserve a non-linear trend of increasing He/ CO2 ratios through time that correlate very well with the measured pressure drop from CO2 dissolution. This indicates that gas composition, in particular the He/ CO2-ratio, can be used to infer the amount of dissolved CO2 in the field where pressure evolution is not available. Our experiments show that the rate of dissolution is determined by convective mass transfer in the brine. Convective transport is driven by the increase of water density with increasing CO2 saturation. However, unlike previous experiments with analog systems we do not observe a constant dissolution rate. This is due to the continued drop in gas pressure that continuously reduces the equilibrium aqueous CO2 concentration and with it the driving force for convection. This feed back may significantly reduce the magnitude of solubility trapping that can be expected during geological CO2 storage.

Larson, T.; Hesse, M. A.

2013-12-01

414

A study of nitrogen and carbon dioxide chemisorption on platinum black  

Microsoft Academic Search

The relationship between sites responsible for nitrogen chemisorption and sites responsible for stronger adsorption of carbon dioxide on platinum black is reported. A 2 to 1 ratio has been found between molecules of more strongly adsorbed carbon dioxide and molecules of nitrogen chemisorbed on individual samples. This relationship has allowed us to deduce the structure of chemisorbed carbon dioxide. Carbon

E. F. Rissmann; J. M. Parry

1992-01-01

415

Modeling carbon dioxide, pH, and un-ionized ammonia relationships in serial reuse systems  

Microsoft Academic Search

In serial reuse systems, excretion of metabolic carbon dioxide has a significant impact on ambient pH, carbon dioxide, and un-ionized ammonia concentrations. This impact depends strongly on alkalinity, water flow rate, feeding rate, and loss of carbon dioxide to the atmosphere. A reduction in pH from metabolic carbon dioxide can significantly reduce the un-ionized ammonia concentration and increase the carbon

John Colt; Barnaby Watten; Michael Rust

2009-01-01

416

CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS  

SciTech Connect

The objective of this project is to develop a simple, inexpensive process to separate CO{sub 2} as an essentially pure stream from a fossil fuel combustion system using a regenerable, sodium-based sorbent. The sorbents being investigated in this project are primarily alkali carbonates, and particularly sodium carbonate and potassium carbonate, which are converted to bicarbonates, through reaction with carbon dioxide and water vapor. Bicarbonates are regenerated to carbonates when heated, producing a nearly pure CO{sub 2} stream after condensation of water vapor. This quarter, electrobalance tests conducted at LSU indicated that exposure of sorbent to water vapor prior to contact with carbonation gas does not significantly increase the reaction rate. Calcined fine mesh trona has a greater initial carbonation rate than calcined sodium bicarbonate, but appears to be more susceptible to loss of reactivity under severe calcination conditions. The Davison attrition indices for Grade 5 sodium bicarbonate, commercial grade sodium carbonate and extra fine granular potassium carbonate were, as tested, outside of the range suitable for entrained bed reactor testing. Fluidized bed testing at RTI indicated that in the initial stages of reaction potassium carbonate removed 35% of the carbon dioxide in simulated flue gas, and is reactive at higher temperatures than sodium carbonate. Removals declined to 6% when 54% of the capacity of the sorbent was exhausted. Carbonation data from electrobalance testing was correlated using a shrinking core reaction model. The activation energy of the reaction of sodium carbonate with carbon dioxide and water vapor was determined from nonisothermal thermogravimetry.

David A. Green; Brian S. Turk; Raghubir P. Gupta; William J. McMichael; Douglas P. Harrison; Ya Liang

2002-04-01

417

Carbonic Acid as a Reserve of Carbon Dioxide on Icy Moons: The Formation of Carbon Dioxide (CO2) in a Polar Environment  

NASA Astrophysics Data System (ADS)

Carbon dioxide (CO2) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ?3 band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO2 band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H2O)-carbon dioxide (CO2) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ?3 band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

2014-06-01

418

Buckling of block copolymer lamellae in supercritical carbon dioxide  

NASA Astrophysics Data System (ADS)

Supercritical carbon dioxide (scCO2) swells many kinds of polymers. In particular polymers containing fluorine are highly swollen. Therefore, block copolymers having fluorinated blocks are expected to be swollen selectively in scCO2 due to the higher affinity of scCO2 toward the fluorinated blocks. We studied the phase behavior of fluorinated block copolymers swollen in scCO2 and found multiple order-to-order transitions as a function of pressure. In addition, the swollen structures could be frozen by reducing temperature and subsequently carbon dioxide was removed without disturbing the swollen morphologies. As a result, the volume occupied with carbon dioxide was converted to empty space, and hence a variety of nanoporous structures were successfully formed. In particular we found that swollen lamellae in scCO2 becomes undulated lamellae with a large wavelength, which is similar to ''egg cartoon'' often observed in unbinding membranes of surfactants.

Yokoyama, Hideaki; Ito, Masateru; Sakai, Yasuhiro; Ito, Kozo; Sugiyama, Kenji

2010-03-01

419

Atmospheric carbon dioxide record from flask measurements at Lampedusa Island  

NSDL National Science Digital Library

Air samples from Lampedusa Island, located south of Sicily in the Mediterranean sea, were collected weekly from May 1992 through December 2000 and analyzed for carbon dioxide content. "On the basis of annual averages calculated from monthly averages, CO2 levels at Lampedusa Island have risen from 360.80 in 1993 to 371.27 in 2000. The data show an average trend of +1.5 ppmv/y." The data from the study, newly available this month from the Carbon Dioxide Information Analysis Center (CDIAC), include a plot of mean carbon dioxide concentration (ppmv) against time and a text table of the annual mean values. Methods, notes, and references are also provided.

Chamard, Paolo.; Ciattaglia, Luigi.; Di Sarra, Alcide.; Monteleone, Francesco.

2001-01-01

420

Exposures to carbon dioxide in the poultry processing industry  

SciTech Connect

The use of dry ice has increased dramatically in poultry processing plants because of changes in the fast food industry. Concentrations of carbon dioxide in four such plants were measured and were found to exceed the Immediately Dangerous to Life and Health Level (50,000 ppm) inside holding coolers where ventilation is poor. In other areas, where dry ice is delivered to poultry packages, time-weighted average exposures can exceed the threshold limit value of 5000 ppm by substantial margins, even if local exhaust ventilation systems are present. Reports of adverse health effects from carbon dioxide exposure and various control measures are reviewed. Recommendations regarding sampling and analytical techniques also are presented. Operators of poultry plants where dry ice is used need to recognize the occupational hazards of exposure to carbon dioxide.

Jacobs, D.E.; Smith, M.S.

1988-12-01

421

Cleaning of ITO glass with carbon dioxide snow jet spray  

NASA Astrophysics Data System (ADS)

ITO glass cleaning is LCD, OLED and other flat panel display industry's key technologies. At present, the usual wet cleaning technology consumes large amount of water and chemicals, and produces a large amount of contaminant venting. CO2 snow jet spray cleaning has been successfully applied to cleaning the surface of semiconductor chip, vacuum devices and space telescopes. Surface cleaning of indium tin oxide (ITO) film was carried out with carbon dioxide snow jet treatment .Based on the measurements of the contact angles, X-ray photoelectron spectroscopy and scanning electron microscopy (SEM) ,the influence of carbon dioxide snow jet treatment on surface cleaning of indium tin Oxide film was investigated and compared with the samples of low frequency immersion ultrasonic cleaning. Experimental data show that the carbon dioxide snow jet treatment effectively removes particulate and hydrocarbon on ITO surface.

Li, Jun-jian; Qi, Tong; Li, Shu-lin; Zhao, Guang

2007-12-01

422

High-brightness all semiconductor laser at 1.57 ?m for space-borne lidar measurements of atmospheric carbon dioxide: device design and analysis of requirements  

NASA Astrophysics Data System (ADS)

The availability of suitable laser sources is one of the main challenges in future space missions for accurate measurement of atmospheric CO2. The main objective of the European project BRITESPACE is to demonstrate the feasibility of an all-semiconductor laser source to be used as a space-borne laser transmitter in an Integrated Path Differential Absorption (IPDA) lidar system. We present here the proposed transmitter and system architectures, the initial device design and the results of the simulations performed in order to estimate the source requirements in terms of power, beam quality, and spectral properties to achieve the required measurement accuracy. The laser transmitter is based on two InGaAsP/InP monolithic Master Oscillator Power Amplifiers (MOPAs), providing the ON and OFF wavelengths close to the selected absorption line around 1.57 ?m. Each MOPA consists of a frequency stabilized Distributed Feedback (DFB) master oscillator, a modulator section, and a tapered semiconductor amplifier optimized to maximize the optical output power. The design of the space-compliant laser module includes the beam forming optics and the thermoelectric coolers. The proposed system replaces the conventional pulsed source with a modulated continuous wave source using the Random Modulation-Continuous Wave (RM-CW) approach, allowing the designed semiconductor MOPA to be applicable in such applications. The system requirements for obtaining a CO2 retrieval accuracy of 1 ppmv and a spatial resolution of less than 10 meters have been defined. Envelope estimated of the returns indicate that the average power needed is of a few watts and that the main noise source is the ambient noise.

Esquivias, I.; Consoli, A.; Krakowski, M.; Faugeron, M.; Kochem, G.; Traub, M.; Barbero, J.; Fiadino, P.; Ai, Xiao; Rarity, J.; Quatrevalet, M.; Ehret, G.

2014-05-01

423

Modelling interactions of carbon dioxide, forests, and climate  

SciTech Connect

Atmospheric carbon dioxide is rising and forests and climate is changing! This combination of fact and premise may be evaluated at a range of temporal and spatial scales with the aid of computer simulators describing the interrelationships between forest vegetation, litter and soil characteristics, and appropriate meteorological variables. Some insights on the effects of climate on the transfers of carbon and the converse effect of carbon transfer on climate are discussed as a basis for assessing the significance of feedbacks between vegetation and climate under conditions of rising atmospheric carbon dioxide. Three main classes of forest models are reviewed. These are physiologically-based models, forest succession simulators based on the JABOWA model, and ecosystem-carbon budget models that use compartment transfer rates with empirically estimated coefficients. Some regression modeling approaches are also outlined. Energy budget models applied to forests and grasslands are also reviewed. This review presents examples of forest models; a comprehensive discussion of all available models is not undertaken.

Luxmoore, R.J. [Oak Ridge National Lab., TN (United States); Baldocchi, D.D. [National Oceanic and Atmospheric Administration, Oak Ridge, TN (United States)

1994-09-01

424

Electricity Load and Carbon Dioxide Emissions: Effects of a Carbon Price in the Short Term  

Microsoft Academic Search

Stabilizing atmospheric carbon dioxide levels at acceptable levels will require a dramatic de-carbonization of the electric generation sector in the U.S. One increasingly discussed way to meet this policy goal is to put an explicit price on carbon emissions, either through a tax or a trading scheme. Increasing demand response has also been discussed as a way to reduce carbon

Adam Newcomer; Seth Blumsack; Jay Apt; Lester B. Lave; M. Granger Morgan

2008-01-01

425

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Test for carbon dioxide in inspired gas; open- and...Apparatus § 84.97 Test for carbon dioxide in inspired gas; open- and... (1) The concentration of carbon dioxide in inspired gas in...

2010-10-01

426

42 CFR 84.97 - Test for carbon dioxide in inspired gas; open- and closed-circuit apparatus; maximum allowable...  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Test for carbon dioxide in inspired gas; open- and...Apparatus § 84.97 Test for carbon dioxide in inspired gas; open- and... (1) The concentration of carbon dioxide in inspired gas in...

2009-10-01

427

Cerebrovascular reactivity to carbon dioxide in Alzheimer's disease. A review  

PubMed Central

There is growing evidence that cerebrovascular reactivity to carbon dioxide (CVRCO2) is impaired in Alzheimers disease (AD). Preclinical and animal studies suggest chronic hypercontractility in brain vessels in AD. We review (a) preclinical studies of mechanisms for impaired CVRCO2 in AD; (b) clinical studies of cerebrovascular function in subjects with AD dementia, mild cognitive impairment (MCI), and normal cognition. Although results of clinical studies are inconclusive, an increasing number of reports reveal an impairment of vascular reactivity to carbon dioxide in subjects with AD, and possibly also in MCI. Thus, CVRCO2 may be an attractive means to detect an early vascular dysfunction in subjects at risk.

Glodzik, Lidia; Randall, Catherine; Rusinek, Henry; de Leon, Mony J.

2013-01-01

428

Experimental Comparison of Nitrogen and Carbon Dioxide Oil Displacement in Carbonate Cores  

Microsoft Academic Search

The feasibility of nitrogen and carbon dioxide flooding is being investigated experimentally as possible enhanced oil recovery processes in Iranian carbonate oil fields. Laboratory tests were conducted on a tight permeability sample of an Iranian oil field. Three flooding tests were conducted at back pressures of 1,000, 2,000, and 2,500 psi for both nitrogen and carbon dioxide separately. All tests

M. Ghasemi; S. R. Shadizadeh

2011-01-01

429

Carbon nanotube-coated surface acoustic wave sensor for carbon dioxide sensing  

Microsoft Academic Search

Carbon dioxide gas sensors have been fabricated by self-assembling single-wall nanotube films on a surface acoustic wave delay line operating at 286MHz. Polymer functionalization was used to enhance the sensitivity of the carbon nanotubes to carbon dioxide. A pulse radar-type interrogation system was used to monitor the conductivity of the nanotube film by measuring the attenuation of the surface acoustic

S. Sivaramakrishnan; R. Rajamani; C. S. Smith; K. A. McGee; K. R. Mann; N. Yamashita

2008-01-01

430

BRIEF COMMUNICATIONS: Investigation of the gain and emission spectrum of a TE laser utilizing a mixture of isotopically substituted carbon dioxide molecules  

Microsoft Academic Search

The results are presented of theoretical and experimental investigations of the gain and emission spectrum of a TE laser utilizing a mixture of isotopically substituted 12CO2 and 13CO2 molecules. It was found that, in a wide range of active-medium pressures (p = 100-3500 Torr) and excitation levels (T3 = 1200-2400 K), a gas mixture such the concentration of 13CO2 (x13)

V. O. Petukhov; N. N. Sazhina; V. S. Starovoitov; S. A. Trushin; N. V. Cheburkin; S. K. Chekin; V. V. Churakov

1985-01-01

431

Aesthetic management of gingival recession by root biomodification with carbon dioxide laser and subepithelial connective tissue graft with lateral repositioned flap technique  

PubMed Central

Localised gingival recessions continue to represent an important aesthetic condition requiring treatment in periodontics. Various techniques have been tried to treat exposed root surfaces to improve aesthetics with high percentage of success and minimal discomfort. Root biomodification is done to improve the predictability of these procedures. This clinical report describes periodontal plastic procedure involving subepithelial connective tissue graft with lateral repositioned flap technique and root biomodification with CO2 laser for the management of gingival recession.

Rastogi, Pavitra Kumar; Lal, Nand; Garg, Nimit; Anand, Vishal; Singhal, Rameshwari

2012-01-01

432

Preliminary results of an aircraft system based on near-IR diode lasers for continuous measurements of the concentration of methane, carbon dioxide, water and its isotopes  

NASA Astrophysics Data System (ADS)

The Federal Agency for Hydrometeorology of the Russian Federation created the flying laboratory on board the passenger airplane Yak-42D for geophysical monitoring of the environment, including aircraft measurements of vertical concentrations of greenhouse gases in the troposphere. Within the limits of this project, General Physics Institute of the Russian Academy of Science developed airborne tunable diode laser spectrometer (TDLS) on the basis of diode lasers of a near-IR range for measurement of the altitude profiles of CO2, CH4, H2O and its isotopes. TDLS complex was integrated aboard in standard 19-in. rack. Air samples, taken over an aircraft on the pipeline, were injected into the optical cell. Using the system of inflow and heating, the air was set laminar with a flowrate of 0.2 l/s at a reduced pressure of 100 mbar for detecting narrow absorption lines of water vapor isotopes. For registration of the absorption spectra and for the measurement of greenhouse gas concentrations in online mode, modulation-correlation technique was used. Diode laser spectrometer output data were transferred to the airborne central computer. Sensitivity of TDLS measurements was 20-30 ppm for water, 3-4 ppm for CO2 and 20-25 ppb for CH4. Time of one-unit measurement is about 30 ms.

Nadezhdinsky, A. I.; Ponurovsky, Ya. Ya.; Shapovalov, Y. P.; Popov, I. P.; Stavrovsky, D. B.; Khattatov, V. U.; Galaktionov, V. V.; Kuzmichev, A. S.

2012-11-01

433

Classroom Demonstration: Combustion of Diamond to Carbon Dioxide Followed by Reduction to Graphite  

ERIC Educational Resources Information Center

An educational demonstration shows the combustion of carbon to carbon dioxide and then the reduction of carbon dioxide to carbon. A melee diamond is the source of the carbon and the reaction is carried out in a closed flask. The demonstration helps students to realize that diamonds are made of carbon and that atoms do not change or vanish in

Miyauchi, Takuya; Kamata, Masahiro

2012-01-01

434

Electrochemical cell for obtaining oxygen from carbon dioxide atmospheres  

NASA Technical Reports Server (NTRS)

For manned missions to Mars to become a reality, an efficient and reliable means of obtaining oxygen from the carbon dioxide-rich atmosphere will be required. Otherwise, the high cost of transporting the oxygen needed to sustain the astronauts will severely restrict the expedition to the martian surface. Recently, the use of electrochemical devices has been explored as a means of obtaining oxygen from the carbon dioxide-rich atmosphere. In these devices, oxygen ions diffuse through solid oxide membranes, thus, separating oxygen from the other gases presented. This phenomenon has only recently been explored as a means of obtaining large quantities of oxygen from toxic atmospheres, although first observed by Walter nernst in 1899. Nernst observed that stabilized zirconia will conduct oxygen ions when an electrical potential is applied across metallic electrodes applied to the ceramic membrane. Diatomic oxygen molecules are dissociated at the positive electrode/electrolyte interface. The oxygen ions enter the ceramic body due to the ion density gradient which is produced by the electrical potential across the electrolytic membrane. Once the ions have diffused through the membrane, they reform diatomic oxygen molecules at the anode. The separation of oxygen from carbon dioxide is achieved by the combination of thermal and electrochemical processes. The thermal decomposition of carbon dioxide (at 1000 C) results in the production of carbon monoxide and oxygen by the reaction.

Hooker, M. W.; Rast, H. E.; Rogers, D. K.

1989-01-01

435

Carbon dioxide adsorption in graphene sheets  

Microsoft Academic Search

Control over the CO2 emission via automobiles and industrial exhaust in atmosphere, is one of the major concerns to render environmental friendly milieu. Adsorption can be considered to be one of the more promising methods, offering potential energy savings compared to absorbent systems. Different carbon nanostructures (activated carbon and carbon nanotubes) have attracted attention as CO2 adsorbents due to their

Ashish Kumar Mishra; Sundara Ramaprabhu

2011-01-01

436

40 CFR 180.1049 - Carbon dioxide; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Carbon dioxide; exemption from...PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...Tolerances § 180.1049 Carbon dioxide; exemption...

2010-07-01

437

40 CFR 180.1049 - Carbon dioxide; exemption from the requirement of a tolerance.  

Code of Federal Regulations, 2010 CFR

... 2009-07-01 false Carbon dioxide; exemption from...PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD...Tolerances § 180.1049 Carbon dioxide; exemption...

2009-07-01

438

27 CFR 27.42a - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Still wines containing carbon dioxide. 27.42a Section 27...and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE...27.42a Still wines containing carbon dioxide. Still wines may...

2010-04-01

439

27 CFR 27.42a - Still wines containing carbon dioxide.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Still wines containing carbon dioxide. 27.42a Section 27...and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE...27.42a Still wines containing carbon dioxide. Still wines may...