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Full-Text Articles in Engineering

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu Dec 2012

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu

Electronic Thesis and Dissertation Repository

This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and …


One-Step Spray Pyrolysis Synthesized Cuo-Carbon Composite Combined With Carboxymethyl Cellulose Binder As Anode For Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, Shulei Chou, Konstantin Konstantinov, Hua Liu Nov 2012

One-Step Spray Pyrolysis Synthesized Cuo-Carbon Composite Combined With Carboxymethyl Cellulose Binder As Anode For Lithium-Ion Batteries, Chao Zhong, Jia-Zhao Wang, Xuan-Wen Gao, Shulei Chou, Konstantin Konstantinov, Hua Liu

Shulei Chou

Copper oxide-carbon composite with hollow sphere structure has been synthesized by a one-step spray pyrolysis method and tested as anode material for lithium-ion batteries. Different analytical methods, including X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometry, thermogravimetric analysis, and systematic electrochemical tests were performed. The results demonstrate that the CuO-carbon composite in conjunction with carboxymethyl cellulose (CMC) binder has an excellent electrochemical performance, with a capacity of 577 mAh g-1 up to 100 cycles. The usage of the water soluble binder, CMC, not only obviously improves the electrochemical performance, but also makes the electrode fabrication process much easier and …


Zawartość Węgla I Siarki W Pyle Pm2,5 I Pm10 W Powietrzu W Centrum Krakowa, Monika Dziugieł, Marek Bogacki, Robert Oleniacz, Marian Mazur Oct 2012

Zawartość Węgla I Siarki W Pyle Pm2,5 I Pm10 W Powietrzu W Centrum Krakowa, Monika Dziugieł, Marek Bogacki, Robert Oleniacz, Marian Mazur

Robert Oleniacz

This paper presents the results of the PM2.5 and PM10 mass concentration measurements in an urban air and results obtained from the additional chemical analysis concerning carbon and sulfur content of the collected dust samples. Dust samples were collected at the measuring point located on the roof of five-storey building at the AGH University of Science and Technology in Krakow, Poland (the center of the urban area of the city). In the scope of this study the relations between the carbon and sulfur content within the collected dust samples were determined in the function of the dust fraction content and …


Putting The Wind At Our Backs: Assessing U.S. Potential For 20% Wind Energy By 2030, Kevin T. Harnett Jun 2012

Putting The Wind At Our Backs: Assessing U.S. Potential For 20% Wind Energy By 2030, Kevin T. Harnett

Honors Theses

The discussion surrounding the future of energy, particularly in the United States, has gained significant momentum in recent years for an obvious reason — it’s daunting. Our dependence on fossil fuels has positioned our nation in an undesirable predicament with a questionable future. With the associated consequences, principally Climate Change, it is essential that energy be addressed as a primary national concern. Renewables need to flip the switch.


Modeling Biofuel Production In Southern Pine Forests: The Effects On Soil Properties, Brittany L. Oakes Jun 2012

Modeling Biofuel Production In Southern Pine Forests: The Effects On Soil Properties, Brittany L. Oakes

Honors Theses

From consuming energy alone in 2009, the United States ranked second as a carbon emitter at 5,425 million metric tons annually; China was the leader at 7,706 million metric tons and India placed third at 1,591 million metric tons (EIA, 2010). Yet in 2009, the U.S. consumed more electricity than both China and India and was the leading importer of electricity (EIA, 2010). Incorporating more domestic sources of renewable energy can simultaneously alleviate two issues: mitigating climate change catastrophes and significantly reduce our dependence on foreign markets for electricity and other forms of energy. Additionally, evidence of dwindling international oil …


Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock May 2012

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Graduate Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths. …


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 Jan 2012

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 Jan 2012

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 …


Enhanced Hydrogen Storage Properties Of Naalh4 Co-Catalysed With Niobium Fluoride And Single-Walled Carbon Nanotubes, Jianfeng Mao, Zaiping Guo, Hua-Kun Liu Jan 2012

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 …


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 Jan 2012

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.


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 Jan 2012

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 …


Power To You: Carbon Nanotube Muscles Are Going Strong, Geoffrey M. Spinks Jan 2012

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.


Development Of Interatomic Potentials For Large Scale Molecular Dynamics Simulations Of Carbon Materials Under Extreme Conditions, Romain Perriot Jan 2012

Development Of Interatomic Potentials For Large Scale Molecular Dynamics Simulations Of Carbon Materials Under Extreme Conditions, Romain Perriot

USF Tampa Graduate Theses and Dissertations

The goal of this PhD research project is to devise a robust interatomic potential for large scale molecular dynamics simulations of carbon materials under extreme conditions. This screened-environment dependent reactive empirical bond order potential (SED-REBO) is specifically designed to describe carbon materials under extreme compressive or tensile stresses. Based on the original REBO potential by Brenner and co workers, SED-REBO includes reparametrized pairwise interaction terms and a new screening term, which serves the role of a variable cutoff. The SED-REBO potential overcomes the deficiencies found with the most commonly used interatomic potentials for carbon: the appearance of artificial forces due …