Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 14 of 14

Full-Text Articles in Life Sciences

The Amazon Frontier Of Land-Use Change: Croplands And Consequences For Greenhouse Gas Emissions, Gillian L. Galford, Jerry Melillo, John F. Mustard, Carlos E.P. Cerri, Carlos C. Cerri Oct 2010

The Amazon Frontier Of Land-Use Change: Croplands And Consequences For Greenhouse Gas Emissions, Gillian L. Galford, Jerry Melillo, John F. Mustard, Carlos E.P. Cerri, Carlos C. Cerri

Rubenstein School of Environment and Natural Resources Faculty Publications

The Brazilian Amazon is one of the most rapidly developing agricultural frontiers in the world. The authors assess changes in cropland area and the intensification of cropping in the Brazilian agricultural frontier state of Mato Grosso using remote sensing and develop a greenhouse gas emissions budget. The most common type of intensification in this region is a shift from single-to double-cropping patterns and associated changes in management, including increased fertilization. Using the enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, the authors created a green-leaf phenology for 2001-06 that was temporally smoothed with a wavelet filter. …


Carbon Dynamics In A Phragmites Australis Invaded Riparian Wetland, Steven Walters Jan 2010

Carbon Dynamics In A Phragmites Australis Invaded Riparian Wetland, Steven Walters

School of Natural Resources: Dissertations, Theses, and Student Research

Invasive plant species are widely recognized as a major threat to biodiversity and ecosystem stability. Wetland ecosystems tend to be much more susceptible to invasions because of their location on the landscape where water, nutrients, and the impacts of disturbances accumulate. Invasive plants have the ability to alter ecosystem processes and community/population dynamics. The ability of invasive plants to alter these processes can have profound economic consequences. In the United States, control of invasive wetland species alone costs approximately 155 million dollars annually. The state of Nebraska spends 2 million dollars annually controlling invasive plant species in the Platte River …


Extrusion Printing Conducting Gel-Carbon Nanotube Structures Upon Flexible Substrates, Geoffrey Pidcock, Marc In Het Panhuis Jan 2010

Extrusion Printing Conducting Gel-Carbon Nanotube Structures Upon Flexible Substrates, Geoffrey Pidcock, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

Extrusion printing was investigatedas a wet-processing method forfabrication of robust, flexible conductingstructures. Layer resistance values of 7 -8 kO/cm were obtained for one printedlayer on flexible substrates. Increasingthe number of extrusion printed layer significantlyimproved resistance.


Diffusion Of Vitamin B12 In Gellan Gum-Carbon Nanotube Hydrogels, Cameron Ferris, Marc In Het Panhuis Jan 2010

Diffusion Of Vitamin B12 In Gellan Gum-Carbon Nanotube Hydrogels, Cameron Ferris, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

We report on the diffusion of vitamin B12 through gellan gum-carbon nanotube hydrogels. The addition of carbon nanotubes to gellan gum reduced the vitamin B12 diffusion coefficient from 1.70 x 10-6 cm2/s to 0.70 x 10-6 cm2/s.


Source Attribution And Interannual Variability Of Arctic Pollution In Spring Constrained By Aircraft (Arctas, Arcpac) And Satellite (Airs) Observations Of Carbon Monoxide, J A. Fisher, D J. Jacob, M T. Purdy, M Kopacz, P Le Sager, C C. Carouge, C D. Holmes, R M. Yantosca, R L. Batchelor, K Strong, G S. Diskin, H E. Fuelberg, J S. Holloway, E J. Hyer, W. W Mcmillan, J Warner, D G. Streets, Q Zhang, Y Yang, S Wu Jan 2010

Source Attribution And Interannual Variability Of Arctic Pollution In Spring Constrained By Aircraft (Arctas, Arcpac) And Satellite (Airs) Observations Of Carbon Monoxide, J A. Fisher, D J. Jacob, M T. Purdy, M Kopacz, P Le Sager, C C. Carouge, C D. Holmes, R M. Yantosca, R L. Batchelor, K Strong, G S. Diskin, H E. Fuelberg, J S. Holloway, E J. Hyer, W. W Mcmillan, J Warner, D G. Streets, Q Zhang, Y Yang, S Wu

Faculty of Science - Papers (Archive)

We use aircraft observations of carbon monoxide (CO) from the NASA ARCTAS and NOAA ARCPAC campaigns in April 2008 together with multiyear (2003– 2008) CO satellite data from the AIRS instrument and a global chemical transport model (GEOS-Chem) to better understand the sources, transport, and interannual variability of pollution in the Arctic in spring. Model simulation of the aircraft data gives best estimates of CO emissions in April 2008 of 26 Tg month−1 for Asian anthropogenic, 9.4 for European anthropogenic, 4.1 for North American anthropogenic, 15 for Russian biomass burning (anomalously large that year), and 23 for Southeast Asian biomass …


Litter-Carbon Dynamics: The Importance Of Decomposition, Accretion, And Sequestration In Understanding Ecosystem Carbon Cycling, Amy Kochsiek Jan 2010

Litter-Carbon Dynamics: The Importance Of Decomposition, Accretion, And Sequestration In Understanding Ecosystem Carbon Cycling, Amy Kochsiek

School of Biological Sciences: Dissertations, Theses, and Student Research

The atmospheric CO2 concentration has been increasing since the industrial revolution. A proposed mitigation strategy is sequestering carbon (C) in terrestrial ecosystems, either in plant biomass or soil organic matter. The litter-C pool is the second largest C pool in agroecosystems post-harvest, and the amount of litter-C loss has been correlated with ecosystem respiration. Yet, the potential importance of the litter pool as one of the major C pools in a system is relatively unknown. We do, however, know that the size of the litter pool can be affected by increases or decreases in both litter-C production and decomposition, …


Easy Preparation Of Sno2@Carbon Composite Nanofibers With Improved Lithium Ion Storage Properties, Zhixin Chen, Zaiping Guo, Hua-Kun Liu, Guodong Du, Xuebin Yu, Guonan Chen, Peng Zhang, Zunxian Yang Jan 2010

Easy Preparation Of Sno2@Carbon Composite Nanofibers With Improved Lithium Ion Storage Properties, Zhixin Chen, Zaiping Guo, Hua-Kun Liu, Guodong Du, Xuebin Yu, Guonan Chen, Peng Zhang, Zunxian Yang

Faculty of Health and Behavioural Sciences - Papers (Archive)

SnO2@carbon nanofibers were synthesized by a combination of electrospinning and subsequent thermal treatments in air and then in argon to demonstrate their potential use as an anode material in lithium ion battery applications. The as-prepared SnO2@carbon nanofibers consist of SnO2 anoparticles/nanocrystals encapsulated in a carbon matrix and contain many mesopores. Because of the charge pathways, both for the electrons and the lithium ions, and the buffering function provided by both the carbon encapsulating the SnO2 nanoparticles and the mesopores, which tends to alleviate the volumetric effects during the charge/discharge cycles, the nanofibers display a greatly improved reversible capacity of 420 …


Carbon Nanotube Architectures As Catalyst Supports For Proton Exchange Membrane Fuel Cells, Weimin Zhang, Peter Sherrell, Andrew I. Minett, Joselito M. Razal, Jun Chen Jan 2010

Carbon Nanotube Architectures As Catalyst Supports For Proton Exchange Membrane Fuel Cells, Weimin Zhang, Peter Sherrell, Andrew I. Minett, Joselito M. Razal, Jun Chen

Faculty of Science - Papers (Archive)

Catalyst support materials exhibit great influence on the performance and durability of proton exchange membrane (PEM) fuel cells. This minireview article summarises recent developments into carbon nanotube-based support materials for PEM fuel cells, including the membrane electrode assembly (MEA). The advantages of using CNTs to promote catalyst performance and stability, a perspective on research directions and strategies to improve fuel cell performance and durability are discussed. It is hoped that this mini-review will act as a conduit for future developments in catalyst supports and MEA design for PEM fuel cells.


Nanostructured Carbon Electrodes, Gordon G. Wallace, Jun Chen, Dan Li, Simon E. Moulton, Joselito M. Razal Jan 2010

Nanostructured Carbon Electrodes, Gordon G. Wallace, Jun Chen, Dan Li, Simon E. Moulton, Joselito M. Razal

Faculty of Science - Papers (Archive)

In its conducting form, carbon has proven to be a versatile, robust and high performing electrode material in areas such as energy conversion, energy storage and even medical bionics. In our laboratories we have been interested in the fabrication and utilization of nanostructured electrodes based on more recently discovered forms of carbon. These include carbon nanotubes and graphene.


Gel-Carbon Nanotube Materials: The Relationship Between Nanotube Network Connectivity And Conductivity, Naratip Songmee, Pisith Singjai, Marc In Het Panhuis Jan 2010

Gel-Carbon Nanotube Materials: The Relationship Between Nanotube Network Connectivity And Conductivity, Naratip Songmee, Pisith Singjai, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

The electrical resistance of carbon nanotube networks (NNs) prepared from combinations of gellan gum, xanthan gum, Triton X-100, SWNT and MWNT is reported. It is demonstrated that the NN conductivity can be obtained by analysing the resistance of two overlapping NN as a function of their overlap distance. Unexpectedly, the connectivity between two overlapping NN was found to scale with the electrical conductivity over 4 orders of magnitude. Insights into the dependence of inter-NN contact on applied pressure were obtained.


Inkjet Printed Conducting Gel-Carbon Nanotube Materials, A Aldalbahi, Marc In Het Panhuis Jan 2010

Inkjet Printed Conducting Gel-Carbon Nanotube Materials, A Aldalbahi, Marc In Het Panhuis

Faculty of Science - Papers (Archive)

The inkjet printing of CNTbiopolymer composite inks onto solid and gel substrates was investigated. Changing the substrate from glass to gel resulted in an increase in the resistance of printed materials from 9.85 kΩ/cm to 39.42 kΩ/cm.


Calibration Of The Total Carbon Column Observing Network Using Aircraft Profile Data, Debra Wunch, G C Toon, Paul O. Wennberg, Steven C. Wofsy, Robert S. Stephens, M K.R. Fischer, O Uchino, J Abshire, P Bernath, S C Biraud, J-F Blavier, C Boone, K P. Bowman, E V. Browell, T Campos, B Connor, Bruce C. Daube, Nicholas M. Deutscher, M Diao, J W. Elkins, Christoph Gerbig, E Gottlieb, David W. Griffith, D F. Hurst, Rodrigo Jimenez, Gretchen Keppel-Aleks, E A. Kort, Ronald Macatangay, T Machidda, H Matsueda, F Moore, I Morino, S Park, J Robinson, C M. Roehl, Y Sawa, V Sherlock, C Sweeney, T Tanaka, M A. Zondlo Jan 2010

Calibration Of The Total Carbon Column Observing Network Using Aircraft Profile Data, Debra Wunch, G C Toon, Paul O. Wennberg, Steven C. Wofsy, Robert S. Stephens, M K.R. Fischer, O Uchino, J Abshire, P Bernath, S C Biraud, J-F Blavier, C Boone, K P. Bowman, E V. Browell, T Campos, B Connor, Bruce C. Daube, Nicholas M. Deutscher, M Diao, J W. Elkins, Christoph Gerbig, E Gottlieb, David W. Griffith, D F. Hurst, Rodrigo Jimenez, Gretchen Keppel-Aleks, E A. Kort, Ronald Macatangay, T Machidda, H Matsueda, F Moore, I Morino, S Park, J Robinson, C M. Roehl, Y Sawa, V Sherlock, C Sweeney, T Tanaka, M A. Zondlo

Faculty of Science - Papers (Archive)

The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Orga-nization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. These calibrations are …


Preliminary Validation Of Column-Averaged Volume Mixing Ratios Of Carbon Dioxide And Methane Retrieved From Gosat Short-Wavelength Infrared Spectra, I Morino, O Uchino, M Inoue, Y Yoshida, T Yokota, P Wennberg, G C Toon, Debra Wunch, C M. Roehl, J Notholt, T Warneke, Janina Messerschmidt, David W. Griffith, Nicholas M. Deutscher, V Sherlock, B Connor, J Robinson, R Sussmann, M Rettinger Jan 2010

Preliminary Validation Of Column-Averaged Volume Mixing Ratios Of Carbon Dioxide And Methane Retrieved From Gosat Short-Wavelength Infrared Spectra, I Morino, O Uchino, M Inoue, Y Yoshida, T Yokota, P Wennberg, G C Toon, Debra Wunch, C M. Roehl, J Notholt, T Warneke, Janina Messerschmidt, David W. Griffith, Nicholas M. Deutscher, V Sherlock, B Connor, J Robinson, R Sussmann, M Rettinger

Faculty of Science - Papers (Archive)

Column-averaged volume mixing ratios of carbon dioxide and methane retrieved from the Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed observation (GOSAT SWIR XCO2 and XCH4) were compared with the reference data ob- 5 tained by ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) participating in the Total Carbon Column Observing Network (TCCON). Through calibrations of g-b FTSs with airborne in-situ measurements, the uncertainty of XCO2 and XCH4 associated with the g-b FTS was determined to be 0.8 ppm (0.2%) and 4 ppb (0.2%), respectively. The GOSAT products are validated with 10 these calibrated g-b FTS data. Preliminary results are as follows: …


Linking Measured Carbon Dioxide Exchange By Sugarcane Crops And Biomass Production, O T Denmead, B.C.T. Macdonald, I. White, David W. Griffith, G Bryant, Travis A. Naylor, Stephen R. Wilson, W J. Wang Jan 2010

Linking Measured Carbon Dioxide Exchange By Sugarcane Crops And Biomass Production, O T Denmead, B.C.T. Macdonald, I. White, David W. Griffith, G Bryant, Travis A. Naylor, Stephen R. Wilson, W J. Wang

Faculty of Science - Papers (Archive)

CARBON TRADING and the growing interest in biofuel production from sugarcane necessitate the ability to measure gains and losses of soil organic C which may occur as a result. Modelling and soil sampling suggest that changes in soil C are likely to be < 1 t C/ha/y. Published accounts indicate that confirming such small changes by traditional soil sampling is error-prone and requires investigations of > 10 years. The paper explores the possibility of calculating soil gains or losses by subtracting the carbon stored in the crop biomass from the carbon gained by the crop through the uptake of carbon dioxide supplied by the atmosphere and processes in the soil. Although uptake and storage very nearly balanced each other in one–year measurements in …