Carbon

Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing

by Sefaattin Tongay

We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic... more We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic magnetization loops can be diminished and eventually extinguished with sufficiently long high vacuum anneals at temperatures on the order of 2300 °C. Concomitant with the extinction of ferromagnetism, we observe an anneal-induced increase in grain size (accompanied by possible edge reconstruction) confirmed by X-ray diffraction measurements and improved transport properties, including lower in-plane and out-of-plane resistivity, higher electron and hole mobility and improved charge compensation. The implied reduction of defects and vacancies by annealing suggests that the ferromagnetism of pristine HOPG is correlated with localized states located at zigzag edges, vacancies and related defects.

Spijkerman, E., de Castro, F., & Gaedke, U. (2011). Independent Colimitation for Carbon Dioxide and Inorganic Phosphorus. PLoS ONE, 12(6), e28219.

by Francisco de Castro

Simultaneous limitation of plant growth by two or more nutrients is increasingly acknowledged as a common phenomenon... more Simultaneous limitation of plant growth by two or more nutrients is increasingly acknowledged as a common phenomenon in nature, but its cellular mechanisms are far from understood. We investigated the uptake kinetics of CO2 and phosphorus of the algae Chlamydomonas acidophila in response to growth at limiting conditions of CO2 and phosphorus. In addition, we fitted the data to four different Monod-type models: one assuming Liebigs Law of the minimum, one assuming that the affinity for the uptake of one nutrient is not influenced by the supply of the other (independent colimitation) and two where the uptake affinity for one nutrient depends on the supply of the other (dependent colimitation). In addition we asked whether the physiological response under colimitation differs from that under single nutrient limitation. We found no negative correlation between the affinities for uptake of the two nutrients, thereby rejecting a dependent colimitation. Kinetic data were supported by a better model fit assuming independent uptake of colimiting nutrients than when assuming Liebigs Law of the minimum or a dependent colimitation. Results show that cell nutrient homeostasis regulated nutrient acquisition which resulted in a trade-off in the maximum uptake rates of CO2 and phosphorus, possibly driven by space limitation on the cell membrane for porters for the different nutrients. Hence, the response to colimitation deviated from that to a single nutrient limitation. In conclusion, responses to single nutrient limitation cannot be extrapolated to situations where multiple nutrients are limiting, which calls for colimitation experiments and models to properly predict growth responses to a changing natural environment. These deviations from single nutrient limitation response under colimiting conditions and independent colimitation may also hold for other nutrients in algae and in higher plants

Substrate and material transfer effects on the surface chemistry and texture of diamond-like carbon deposited by plasma-enhanced chemical vapour deposition

by Benjamin Jones

B. J. Jones and  J. J. Ojeda
Surface and Interface Analysis (2012)
[In Press] http://dx.doi.org/10.1002/sia.4871

Highlights
This paper discusses the use of X-ray photoelectron spectroscopy (XPS) and X-ray excited Auger... more Highlights
This paper discusses the use of X-ray photoelectron spectroscopy (XPS) and X-ray excited Auger spectroscopy (XAES) to investigate carbon bonding. The paper demonstrates the application of these techniques to the analysis of diamond-like carbon thin films, and couples them with atomic force microscopy (AFM) measurements of topography for the development of coatings, for example in aerospace applications.

Abstract
Diamond-like carbon (DLC), a thin amorphous carbon film, has many uses in tribological systems. Exploiting alternative substrates and interlayers can enable the control of the hardness and modulus of the multilayer system and improve wear or friction properties. We used XPS and atomic force microscopy to examine DLC that had been concurrently coated on an epoxy interlayer and a steel substrate by plasma-enhanced chemical vapour deposition. sp2/sp3 ratios were calculated both by the deconvolution of the XPS C1s line and by the analysis of the C KLL Auger spectrum. Altering the substrate causes changes in the carbon bonding configuration, evident with the same trend through both analysis methods, although with differing absolute values, related to hydrogen and oxygen content. There is significant variation in the microscale surface texture, exhibited by both average roughness values and size and uniformity of surface asperities. This suggests that alteration to the film surface structure is a factor to be considered in addition to interface adhesion, hardness and elastic modulus in investigating substrates and interlayers for tribological coatings. Examination of a DLC film separately produced on a steel substrate, in comparison with that produced concurrently with a DLC coating on epoxy, shows the possibility of effects on the chemistry of the film through transfer of material from adjacent samples within the plasma deposition, related to heating, outgassing or sputtering processes. The possibility of such contamination has implications in coating parameter design and coating of multiple samples with plasma-enhanced chemical vapour deposition.


Keywords: Diamond; graphite; diamond-like carbon; DLC; amorphous carbon; X-ray; Auger; bonding; thin film; plasma enhanced chemical vapour deposition; surface morphology; surface chemistry;
substrate effects

Time preference: Reply to Tol

by Philip Fearnside

Fearnside, P.M. 2002. Time preference: Reply to Tol. Ecological Economics 41(1): 35-36. doi:10.1016/S0921-8009(02)00015-0

See Amazon Controversies:
http://philip.inpa.gov.br/publ_livres/AMAZONIAN CONTROVERSIES.htm

Estudo avalia impactos do desmatamento na Amazônia

by Philip Fearnside

Fearnside, P.M. 2003. Estudo avalia impactos do desmatamento na Amazônia. Hipertexto. Brasília: Canal Ciência / IBICT. http://www.canalciencia.ibict.br/pesquisa/0093-Impactos-do-desmatamento-na-Amazonia.html

Deforestation in Amazonia

by Philip Fearnside

Fearnside, P.M. 2007. Deforestation in Amazonia. Encyclopedia of Earth. Eds. C.J. Cleveland (General Editor) & M. Hall-Beyer (Topic Editor). Environmental Information Coalition, National Council for Science and the Environment, Washington, D.C., U.S.A. <http://www.eoearth.org/article/Deforestation_in_Amazonia&gt;

Tropical deforestation and global warming

by Philip Fearnside

Fearnside, P.M. 2006. Tropical deforestation and global warming. Science 312: 1137 (letter) DOI: 10.1126/science.312.5777.1137c

Deforestation and carbon emissions projected for southern Amazonas, Brazil: A summary of modeling results for deforestation and emissions in the municipality of Apuí and in the area of the Manaus-Porto Velho (BR-319) Highway over the 2007-2050 period.

by Philip Fearnside

Fearnside, P.M. 2007. Deforestation and carbon emissions projected for southern Amazonas, Brazil: A summary of modeling results for deforestation and emissions in the municipality of Apuí and in the area of the Manaus-Porto Velho (BR-319) Highway over the 2007-2050 period. p. 22. In: Government of the state of Amazonas, Secretariat for the Environment and Sustainable Development (SDS). Amazonas Initiative on Climate Change, Forest Conservation and Sustainable Development. SDS, Manaus, Amazonas, Brazil. 34 pp.

Biomassa e carbono: Incertezas metodológicas para o mecanismo REDD

by Philip Fearnside

Fearnside, P.M. 2009. Biomassa e carbono: Incertezas metodológicas para o mecanismo REDD. pp 28-34. In: RELATÓRIO DO SEMINÁRIO: Perspectivas e Potencial do Mecanismo de Redução de Emissões por Desmatamento e Degradação (REDD) no Estado do Pará. IDESP, MPEG & SEMA, Belém, Pará. http://www.museu-goeldi.br/Relatorio%20Seminario%20REDD_final.pdf

Methane emissions from hydroelectric dams

by Philip Fearnside

Fearnside, P.M. 2011. Methane emissions from hydroelectric dams. Science (E-Letter 28 July 2011), http://www.sciencemag.org/content/331/6013/50.short/reply#sci_el_14254

Amazônia e as negociações de clima

by Philip Fearnside

Fearnside, P.M. 2010. Amazônia e as negociações de clima. Boletim da Sociedade Brasileira de Economia Ecológica (Eco-Eco) Nos. 23-24, pp: 23-28.

TOWARDS A CONCEPTUAL MODEL OF A CARBON BUDGET FOR A FACULTATIVE WASTE STABILISATION POND

by Craig Smeaton

Smeaton, C., Donaldson, J., Reeves, A.D., Cromar, N.J., Buchanan, N.A., Fallowfield, H.J,(2011), 9th IWA Specialist Conference on Waste Stabilisation Ponds, Adelaide, Australia.

Waste stabilization ponds are an effective and inexpensive method for treating wastewater for re-use in agricultural... more Waste stabilization ponds are an effective and inexpensive method for treating wastewater for re-use in agricultural and industrial processes. Carbon in the environment in recent years has become of increasing concern due to the threat of global climate change. The potential for algal–bacterial wastewater treatment systems to recycle carbon via photosynthetic capture of carbon dioxide emitted from energy generation systems is of growing interest. Valorisation of the carbon in the biomass, for example via anaerobic digestion, would reduce fossil fuel consumption and off-set the carbon footprint of the operating utility. This preliminary study investigated the carbon budget of a facultative waste stabilisation pond at Lyndoch, South Australia constructed in 1979. The Lyndoch WSP receives effluent from on-site septic systems and comprises of a primary facultative pond and two maturation ponds. The objective of this research was to develop a conceptual model of a carbon budget for this facultative pond.

Tracking the Hirnantian glaciation using Os isotopes

by Darren Gröcke

Earth & Planetary Science Letters, 293, 339–348, doi:10.1016/j.epsl.2010.02.049

Here we present initial 187Os/188Os (Osi) values integrated with δ13Corg for the first Paleozoic section — the... more Here we present initial 187Os/188Os (Osi) values integrated with δ13Corg for the first Paleozoic section — the Ordovician/Silurian boundary GSSP at Dob's Linn, Scotland. Our 187Os/188Os data tracks major changes in climate that occurred during the Late Ordovician (Hirnantian glaciation), which coincides with the second largest known mass extinction. During the complanatus and early anceps Biozones Osi values increase from 0.28–1.08. This provides evidence for a period of increased silicate weathering of radiogenic continental crust, likely from the Caledonian Orogen. This increase in weathering was likely the driving mechanism for the drawdown in atmospheric CO2 and global cooling that resulted in the onset of the Hirnantian Glaciation. A decrease to less radiogenic Osi occurs at the base Hirnantian extraordinarius Biozone and coincides with the trend to more positive δ13Corg values that mark the onset of the Hirnantian Glaciation. The trend in Osi during this interval is ascribed to Hirnantian ice cover and reduced chemical weathering rates cutting the supply of radiogenic material to the Iapetus Ocean. The reduction in silicate weathering enabled atmospheric CO2 to return back to greenhouse levels, causing rapid deglaciation during the mid persculptus Biozone. This period is marked by an abrupt increase in Osi values from 0.6 to 1.08 over 19 cm of stratigraphy and coincides with the deglacial limb of the δ13Corg profile. We interpret the Osi data to reflect the leaching of exposed radiogenic 187Os/188Os bearing glacial deposits and increased weathering of radiogenic 187Os/188Os silicate terrane during the deglaciation. Previous workers have identified the Hirnantian glaciation primarily through δ13C stratigraphy. However, our Os isotope data indicate that an initial mechanism (i.e. increased silicate weathering) was the driving mechanism behind the Hirnantian Glaciation and subsequent mass extinction. Thus, by coupling Osi and δ13Corg proxies we provide the most direct evidence for the initiation and cessation of the Hirnantian glaciation. Furthermore, this study demonstrates the first use of 187Os/188Os chemostratigraphy for the Paleozoic as a proxy for reconstructing the Earth's climate system, particularly palaeoceanography.

Litterfall dynamics in mangrove Kandelia obovata (S. L.,) Yong stands on Okinawa Island, Japan over four year

by Sahadev Sharma

Above and Belowground Carbon Acquisition of Mangrove Kandelia obovata Trees in Manko Wetland, Okinawa, Japan

by Sahadev Sharma

Sustainability and Dairy Production - Challenges and Opportunities

by Jude (Judith) Capper

Co-authored with Dr. Dale E. Bauman. Published in the Proceedings of the Cornell Nutrition Conference 2011 held in Syracuse, NY.

In Diamond Health: Diamond-like carbon in medical devices

by Benjamin Jones

B Jones and T Anson "In Diamond Health" Materials World 16 [8] (2008) 24

Diamond-like carbon (DLC) is a thin film coating that is dense, inert, low friction and hard wearing.... more Diamond-like carbon (DLC) is a thin film coating that is dense, inert, low friction and hard wearing. Interdisciplinary research, involving materials scientists, physicists, mechanical engineers, biomedical specialists and clinicians, is continuously expanding the potential and applications of DLC and enhanced carbon-based materials in the medical sector. 

This paper investigates diamond-like carbon on medical devices, such as orthopaedic implants, trauma prostheses and laparoscopy surgical tools, and discusses the role of enhanced DLC in the future medical industry.

Synthesis of carbon nanotubes by sequential pyrolysis and combustion of polyethylene

by Chuanwei Zhuo

Power ballads: deploying aversive energy feedback in social media

by Derek Foster

To appear in CHI 2011, May 7-12 Vancouver

This paper reports on the pilot evaluation of “Power Ballads”, an evocative social media application which displays... more This paper reports on the pilot evaluation of “Power Ballads”, an evocative social media application which displays aversive feedback based on excessive household energy usage. Work by other researchers in persuasive technologies has previously suggested the use of aversive feedback should be avoided as it leads to a lack of engagement by users. This work evaluates whether punishment of non-desirable behaviour discourages users from engaging with a persuasive application. To this end we recruited 9 households to use the Power Ballads application over a period of 4 weeks. We found the use of aversive feedback did not act as a deterrent to regularly interacting with the application through evaluating user engagement.

Evidence for bias in C/N, δ13C and δ15N values of bulk organic matter, and on environmental interpretation, from a lake sedimentary sequence by pre-analysis acid treatment methods.

by Chris Brodie

In Press - Quaternary Science Reviews

Lead Author: Dr. Chris Brodie (Hong Kong University, Hong Kong)

Co-Authors: Dr. James Casford (Durham University); Dr. Jeremy Lloyd (Durham University, UK); Prof. Melanie Leng (NIGL, UK); Dr. Timothy Heaton (NIGL, UK); Christopher Kendrick (NIGL, UK); Dr. Zong Yongqiang (Hong Kong University, Hong Kong).

ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid... more ABSTRACT:
There is a known bias in C/N, d13C and d15N values of organic matter (OM) due to pre-analysis acid treatment methods. We report here, for the first time, the results of a pre-analysis acid treatment method comparison of measured C/N, d13C and d15N values in bulk OM from a sedimentary sequence of samples to illustrate this bias. Here we show that acid treatment significantly reduces the accuracy (between method biases) and precision (within method bias) of C/N, d13C and d15N values of OM, suggesting a differential response of sample OM between methods and sample horizons, and in some cases inefficient removal of inorganic carbon. We show that different methods can significantly influence environmental interpretation in some of our sample horizons (i.e. interpretation of aquatic vs. terrestrial OM source; C3 vs. C4 vegetation). Specifically, there are unpredictable and non-linear differences between methods for C/N values in the range of ~ 1 – 100; d13C values in the range of 0.2 – 6.8 ‰ and; d15Nvalues in the range of 0.3 – 0.7 ‰. Importantly, these ranges are mostly much greater than the instrument precision (defined as the standard deviation of replicate analysis of standard reference materials; for this study, ± 0.5 for C/N values, ± 0.1 ‰ for d13C values and; ± 0.1 ‰ for d15N). The accuracy and precision of measured C/N, d13C and d15N values of bulk OM is not just dependent upon environmental variability, but on acid pre-treatment, residual inorganic carbon and organic matter state and composition. Collectively, this makes the correlation between samples prepared in different ways, including those from down core reconstructions, highly questionable.

Keywords: C/N ratios, δ13C, δ15N, organic matter; pre-analysis acid treatment methods, environmental interpretation, palaeoclimate.