Physical Sciences and Mathematics Commons^™

Shedding Light On Plant Litter Decomposition: Advances, Implications And New Directions In Understanding The Role Of Photodegradation, Jennifer Y. King, Leslie A. Brandt, E. Carol Adair

Rubenstein School of Environment and Natural Resources Faculty Publications

Litter decomposition contributes to one of the largest fluxes of carbon (C) in the terrestrial biosphere and is a primary control on nutrient cycling. The inability of models using climate and litter chemistry to predict decomposition in dry environments has stimulated investigation of non-traditional drivers of decomposition, including photodegradation, the abiotic decomposition of organic matter via exposure to solar radiation. Recent work in this developing field shows that photodegradation may substantially influence terrestrial C fluxes, including abiotic production of carbon dioxide, carbon monoxide and methane, especially in arid and semi-arid regions. Research has also produced contradictory results regarding controls on …

Agenda: Drafting Model Laws On Indoor Pollution For Developing And Developed Nations, University Of Colorado Boulder. Center For Energy & Environmental Security, Colorado Natural Resources, Energy And Environmental Law Review

Drafting Model Laws on Indoor Pollution for Developing and Developed Nations (July 12-13)

On July 12 and 13, 2012, experts convened at Colorado Law to demonstrate the extent to which a model law could help address the global problem of indoor air pollution from inefficient cook stoves. The air pollution that results from inefficiently burning biomass as fuel for cooking has serious health and climatic consequences. The workshop produced two sets of Model Laws and commentaries to help nations solve the problem, and the commentaries were published in the Colorado Natural Resources, Energy, and Environmental Law Review.

Drafting Model Laws On Indoor Pollution For Developing And Developed Nations Workshop, July 12-13, 2012, Boulder, Colorado: Introduction, Lakshman Guruswamy

Drafting Model Laws on Indoor Pollution for Developing and Developed Nations (July 12-13)

11 pages.

"This Essay introduces the framework for deliberation and legislative drafting undertaken at the workshop: Drafting Model Laws on Indoor Pollution for Developing and Developed Nations on July 12-13, 2012, in Boulder, Colorado. There are a number of fundamental premises upon which the workshop was based, and this Essay refers to the most salient among them."-- Excerpted from 24 Colo. Nat. Resources, Energy & Envtl. L. Rev. 319 (2013).

Low Energy (E, 2e) Study From The 1t₂ Orbital Of Ch₄, Shenyue Xu, Hari Chaluvadi, Xueguang Ren, Thomas Pfluger, Arne Senftleben, Chuangang Ning, Shuncheng Yan, Peng Zhang, Jie Yang, Xinwen Ma, Joachim Hermann Ullrich, Don H. Madison, Alexander Dorn

Physics Faculty Research & Creative Works

Single ionization of the methane (CH₄) 1t₂ orbital by 54 eV electron impact has been studied experimentally and theoretically. The measured triple differential cross sections cover nearly a 4π solid angle for the emission of low energy electrons and a range of projectile scattering angles. Experimental data are compared with theoretical calculations from the distorted wave Born approximation and the molecular three-body distorted wave models. It is found that theory can give a proper description of the main features of experimental cross section only at smaller scattering angles. For larger scattering angles, significant discrepancies between experiment and …

Variability Of Black Carbon Deposition To The East Antarctic Plateau, 1800-2000 Ad, M. M. Bisiaux, R. Edwards, J. R. Mcconnell, M. R. Albert

Dartmouth Scholarship

Refractory black carbon aerosols (rBC) from biomass burning and fossil fuel combustion are deposited to the Antarctic ice sheet and preserve a history of emissions and long-range transport from low- and mid-latitudes. Antarctic ice core rBC records may thus provide information with respect to past combustion aerosol emissions and atmospheric circulation. Here, we present six East Antarctic ice core records of rBC concentrations and fluxes covering the last two centuries with approximately annual resolution (cal. yr. 1800 to 2000). The ice cores were drilled in disparate regions of the high East Antarctic ice sheet, at different elevations and net snow …

Quantifying Pedogenic Carbon Content Within The Boise River Terraces Using Pressurized Calcimetry, Dawn Jarrels, Annika Quick, Jennifer L. Pierce

College of Arts and Sciences Poster Presentations

Soil carbon is the third largest carbon pool within the global carbon cycle; however, soil carbon amounts are not well quantified, and exchange rates of soil carbon are not well understood. Soil carbon can be divided into organic carbon and inorganic carbon, where inorganic carbon (pedogenic carbonate) is precipitated during soil formation and accumulates over time in semi-arid and arid environments. Calcic soils within the semiarid regions of the Boise Valley result from active pedogenic accumulation of secondary CaCO₃ resulting in prominent 'caliche' layers in soils formed on many of the Boise River terraces. The larger goals of this …

Feeding Habitats Of The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi, In The Suwannee And Yellow Rivers, Florida, As Identified By Multiple Stable Isotope Analyses, Kenneth J. Sulak, J. J. Berg, M. Randall

United States Geological Survey: Staff Publications

Stable ¹³C, ¹⁵N, and ³⁴S isotopes were analyzed to define the feeding habitats of Acipenser oxyrinchus desotoi in the Suwannee and Yellow River populations. For the majority (93.9%) of Suwannee sub adults and adults, 13C and 34S signatures indicate use of nearshore marine waters as primary winter feeding habitat, probably due to the limiting size of the Suwannee Sound estuary. In the Yellow River population, 13C isotope signatures indicate that adults remain primarily within Pensacola Bay estuary to feed in winter, rather than immigrating to the open Gulf of Mexico. A minor Suwannee River subset (6% of …

Interannual And Spatial Impacts Of Phenological Transitions, Growing Season Length, And Spring And Autumn Temperatures On Carbon Sequestration: A North America Flux Data Synthesis, Chaoyang Wu, Alemu Gonsamo, Jing Ming Chen, Werner A. Kurz, David T. Price, Peter M. Lafleur, Rachhpal S. Jassal, Danilo Dragoni, Gil Bohrer, Christopher M. Gough, Shashi B. Verma, Andrew E. Suyker, J. William Munger

School of Natural Resources: Faculty Publications

Understanding feedbacks of ecosystem carbon sequestration to climate change is an urgent step in developing future ecosystem models. Using 187 site-years of flux data observed at 24 sites covering three plant functional types (i.e. evergreen forests (EF), deciduous forests (DF) and non-forest ecosystems (NF) (e.g., crop, grassland, wetland)) in North America, we present an analysis of both interannual and spatial relationships between annual net ecosystem production (NEP) and phenological indicators, including the flux-based carbon uptake period (CUP) and its transitions, degree-day-derived growing season length (GSL), and spring and autumn temperatures. Diverse responses were acquired between annul NEP and these indicators …

Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou

Australian Institute for Innovative Materials - Papers

Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance high-field properties. However, the critical role of carbon remains elusive, and also low-field critical current density has not been improved. Here, we have undertaken malic acid doping of MgB2 and find that the microscopic origin for the enhancement of high-field properties is due to boron vacancies and associated stacking faults, as observed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. The carbon from the malic acid almost uniformly encapsulates …

Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler

Australian Institute for Innovative Materials - Papers

Free-standingsingle-walledcarbonnanotube/SnO₂ (SWCNT/SnO₂) anodepaper was prepared by vacuum filtration of SWCNT/SnO₂ hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO₂ nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO₂ had excellent cyclic retention, with the high specific capacity of 454 mAh g⁻¹ beyond 100 cycles at a current …

Ch4, Co, And H2o Spectroscopy For The Sentinel-5 Precursor Mission: An Assessment With The Total Carbon Column Observing Network Measurements, A Galli, A Butz, R A. Scheepmaker, O Hasekamp, J Landgraf, P Tol, D Wunch, N M. Deutscher, G C. Toon, P O. Wennberg, D W. T Griffith, I Aben

Faculty of Science - Papers (Archive)

The TROPOspheric Monitoring Instrument (TROPOMI) will be part of ESA’s Sentinel-5 Precursor (S5P) satellite platform scheduled for launch in 2015. TROPOMI will monitor methane and carbon monoxide concentrations in the Earth’s atmosphere by measuring spectra of back-scattered sunlight in the short-wave infrared (SWIR).

Atmospheric Carbon Dioxide Retrieved From The Greenhouse Gases Observing Satellite (Gosat): Comparison With Ground-Based Tccon Observations And Geos-Chem Model Calculations, A Cogan, H Boesch, R Parker, L Feng, Paul Palmer, J-F Blavier, Nicholas M. Deutscher, Ronald Macatangay, Justus Notholt, C M. Roehl, Thorsten Warneke, Debra Wunch

Faculty of Science - Papers (Archive)

We retrieved column-averaged dry air mole fractions of atmospheric carbon dioxide (XCO 2) from backscattered short-wave infrared (SWIR) sunlight measured by the Japanese Greenhouse gases Observing SATellite (GOSAT). Over two years of XCO 2 retrieved from GOSAT is compared with XCO 2 inferred from collocated SWIR measurements by seven ground-based Total Carbon Column Observing Network (TCCON) stations. The average difference between GOSAT and TCCON XCO 2 for individual TCCON sites ranges from -0.87 ppm to 0.77 ppm with a mean value of 0.1 ppm and standard deviation of 0.56 ppm. We find an average bias between all GOSAT and TCCON …

Enhanced Hydrogen Storage Properties Of Naalh4 Co-Catalysed With Niobium Fluoride And Single-Walled Carbon Nanotubes, Jianfeng Mao, Zaiping Guo, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

The effects of single-walled carbon nanotubes (SWCNTs) as a co-catalyst with NbF₅ on the dehydrogenation and hydrogenation kinetics of NaAlH₄ were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, differential thermal analysis, temperature-programmed desorption, and isothermal hydrogen ab/desorption techniques. It has been revealed that there is a synergistic effect of SWCNTs and NbF₅ on the de/rehydrogenation of NaAlH4, which improves the hydrogen de/absorption performance when compared to adding either SWCNTs or NbF₅ alone. For example, the apparent activation energy for the first-step and the second-step dehydrogenation of the co-doped NaAlH4 sample is estimated to be 85.9 …

Conducting Composite Materials From The Biopolymer Kappa-Carrageenan And Carbon Nanotubes, Ali Aldalbahi, Jin Chu, Peter Feng, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

Conducting composite films containing carbon nanotubes (CNTs) were prepared by using the biopolymer kappa-carrageenan (KC) as a dispersant. Rheological studies indicated that 0.5% w/v was the appropriate KC concentration for dispersing CNTs. Our results showed that multiwalled nanotubes (MWNTs) required less sonic energy than single-walled nanotubes (SWNTs) for the dispersion process to be complete. Films prepared by vacuum filtration exhibited higher conductivity and improved mechanical characteristics compared to those prepared by evaporative casting. All composite films displayed sensitivity to water vapour, but MWNT films were more sensitive than SWNT films.

Electrical And Mechanical Characteristics Of Buckypapers And Evaporative Cast Films Prepared Using Single And Multi-Walled Carbon Nanotubes And The Biopolymer Carrageenan, Ali Aldalbahi, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

The electrical and mechanical characteristics of composite materials prepared using evaporative casting and vacuum filtration of carbon nanotubes (CNTs) dispersed in the biopolymer s-carrageenan (IC) are reported. It is demonstrated that the contact angle of water with films is proportional to the CNT mass and volume fraction, which is used to compare the properties of buckypapers with those of evaporative cast films. Multi-walled carbon nanotube films were found to exhibit higher conductivity values compared to those observed for single-walled carbon nanotubes composites at comparable contact angle values up to true nanotube volume fraction of 0.12. Buckypapers prepared by varying the …

A Simple Route To Carbon Micro- And Nanorod Hybrid Structures By Physical Vapour Deposition, Jin Chu, Xiaoyan Peng, Ali Aldalbahi, Marc In Het Panhuis, Rafael Velazquez, Peter X. Feng

Faculty of Science - Papers (Archive)

Tilted well-aligned carbon micro- and nano-hybrid rods were synthesized on Si at different substrate temperatures and incident angles of carbon source beam using the hot filament physical vapour deposition technique. The morphologic surfaces, chemical compositions and bond structures of the oblique carbon rod-like structures were investigated by scanning electron microscopy, field emission scanning electron microscopy, transmission electron diffraction and Raman scattering spectroscopy. The field emission behaviour of the fabricated samples was also measured.

Validation Of Iasi Forli Carbon Monoxide Retrievals Using Ftir Data From Ndacc, T Kerzenmacher, B Dils, N Kumps, T Blumenstock, C Clerbaux, P F. Coheur, P Demoulin, Omaira Garcia, M George, David W. Griffith, F Hase, J Hadji-Lazaro, D Hurtmans, Nicholas B. Jones, E Mahieu, Justus Notholt, Clare Paton-Walsh, U Raffalski, T Ridder, M Schneider, C Servais, M De Maziere

Faculty of Science - Papers (Archive)

Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Universit´e Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from groundbased solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny-A° lesund, Kiruna, Bremen, Jungfraujoch, Iza˜na and Wollongong. In order to have good statistics for the comparisons, we …

Power To You: Carbon Nanotube Muscles Are Going Strong, Geoffrey M. Spinks

Australian Institute for Innovative Materials - Papers

Just on a year ago my colleagues and I announced our discovery that carbon nanotube yarns could be made to twist and rotate at great speeds when electrically stimulated. In this way we had created "artificial muscles" that could change their shape in response to stimulus.

The Density Factor In The Synthesis Of Carbon Nanotube Forest By Injection Chemical Vapor Deposition, Robert W. Call, C. Read, C Mart, T. C. Shen

Graduate Student Publications

Beneath the seeming straight-forwardness of growing carbon nanotube(CNT) forests by the injection chemical vapor deposition(CVD) method, control of the forest morphology on various substrates is yet to be achieved. Using ferrocene dissolved in xylene as the precursor, we demonstrate that the concentration of ferrocene and the injection rate of the precursor dictate the CNT density of these forests. However, CNT density will also be affected by the substrates and the growth temperature which determine the diffusion of the catalyst adatoms. The CNT growth rate is controlled by the temperature and chemical composition of the gases in the CVD reactor. We …

Effects Of Activated Carbon Surface Chemistry Modification On The Adsorption Of Mercury From Aqueous Solution, Emily K. Faulconer

Publications

Mercury (Hg), a naturally occurring element, is toxic and can lead to negative health impacts for humans and ecosystems. Activated carbon adsorption is effective in treating Hg-laden aqueous effluent for safe discharge. Two modifications of commercially available activated carbon were investigated: iron impregnation to allow for magnetic sorbent recapture and wet chemical oxidation to enhance aqueous Hg capture. The modified carbons were characterized by nitrogen adsorption-desorption, XRD, pHpzc, vibrating sample magnetometry, elemental analysis, and total acidity titration. The 3:1 C:Fe magnetic powdered activated carbon (MPAC) retained a high surface area of 790 m2 /g and was 95% magnetically recoverable, with …

Hollow Nitrogen Containing Core/Shell Fibrous Carbon Nanomaterials As Support To Platinum Nanocatalysts And Their Tem Tomography Study, Cuifeng Zhou, Zongwen Liu, Xusheng Du, David Rg Mitchell, Yiu-Wing Mai, Yushan Yan, Simon Peter Ringer

Australian Institute for Innovative Materials - Papers

Core/shell nanostructured carbon materials with carbon nanofiber (CNF) as the core and a nitrogen (N)-doped graphitic layer as the shell were synthesized by pyrolysis of CNF/polyaniline (CNF/PANI) composites prepared by in situ polymerization of aniline on CNFs. High-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared and Raman analyses indicated that the PANI shell was carbonized at 900 degress C. Platinum (Pt) nanoparticles were reduced by formic acid with catalyst supports. Compared to the untreated CNF/ PANI composites, the carbonized composites were proven to be better supporting materials for the Pt nanocatalysts and showed superior performance as catalyst …

Irradiation Si On Carbon Nanotube Paper As A Flexible Anode Material For Lithium-Ion Batteries, Shulei Chou, Mihail Ionescu, Jia-Zhao Wang, Brad Winton, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Silicon single walled carbon nanotube composite paper was modified by low energy ion implantation using 5i to obtain a flexible composite paper. Raman and FE-SEM results show that structure of SWCNT could be destroyed by the implantation. Electrochemical measurements display that the implanted SI can improve the specific capacity and the reversible capacity of CNT paper. After 50 cycles, the specific capacity of 5Hmplanted CNT paper is 30 per cent higher than the pristine CNT.