Physical Sciences and Mathematics Commons^™

Ambient Ammonia Synthesis Via Microwave-Catalytic Materials And Plasma Chemistry, Siobhan Brown

Graduate Theses, Dissertations, and Problem Reports

Ammonia is critical to supporting human life on earth because of its use as fertilizer. The Haber-Bosch process to produce ammonia has been practiced for over 100 years. This process operates at high pressure and temperature to overcome the thermodynamic and kinetic limitations of the ammonia synthesis reaction thus researchers have tried to overcome it for decades. At present this process represents 1% of global energy usage and 2.5% of global CO₂ emissions. The proposed chemical looping ammonia synthesis approach seeks to reduce the environmental impact of this critical process and to elucidate microwave-catalytic principles.

This research aims to …

On The Chronological Understanding Of The Homogeneous Dielectric Barrier Discharge, Xinpei Lu, Zhi Fang, Dong Dai, Tao Shao, Feng Liu, Cheng Zhang, Dawei Liu, Lanlan Nie, Chunqi Jiang

Bioelectrics Publications

Dielectric barrier discharges (DBD) are widely utilised non-equilibrium atmospheric pressure plasmas with a diverse range of applications, such as material processing, surface treatment, light sources, pollution control, and medicine. Over the course of several decades, extensive research has been dedicated to the generation of homogeneous DBD (H-DBD), focussing on understanding the transition from H-DBD to filamentary DBD and exploring strategies to create and sustain H-DBD. This paper first discusses the influence of various parameters on DBD, including gas flow, dielectric material, surface conductivity, and mesh electrode. Secondly, a chronological literature review is presented, highlighting the development of H-DBD and the …

The Design Of A Continuous Wave Molecular Nitrogen Stimulated Raman Laser In The Visible Spectrum, Timothy J. Bate

Theses and Dissertations

Hollow-core photonic crystal fibers (HCPCFs) shows promise as a hybrid laser with higher nonlinear process limits and small beam size over long gain lengths. This work focuses on the design of a CW molecular nitrogen (N₂) stimulated Raman laser. N₂ offers Raman gains scaling up to 900 amg, scaling higher than H₂. The cavity experiment showed the need to include Rayleigh scattering in the high pressure required for N₂ Raman lasing. Even at relatively low pressure ssuch as 1,500 psi, high conversion percentages should be found if the fiber length is chosen based on …

Evaluation Of Persistent-Mode Operation In A Superconducting Mgb2 Coil In Solid Nitrogen, Dipakkumar Patel, Md Shahriar Hossain, Khay Wai W. See, Wenbin Qiu, Hiroki Kobayashi, Zongqing Ma, Seong Jun Kim, Jonggi Hong, Jin Yong Park, Seyong Choi, Minoru Maeda, Mohammed Shahabuddin, Matthew A. Rindfleisch, Michael Tomsic, S X. Dou, Jung Ho Kim

Australian Institute for Innovative Materials - Papers

We report the fabrication of a magnesium diboride (MgB2) coil and evaluate its persistent-mode operation in a system cooled by a cryocooler with solid nitrogen (SN2) as a cooling medium. The main purpose of SN2 was to increase enthalpy of the cold mass. For this work, an in situ processed carbon-doped MgB2 wire was used. The coil was wound on a stainless steel former in a single layer (22 turns), with an inner diameter of 109 mm and height of 20 mm without any insulation. The two ends of the coil were then joined to make a persistent-current switch to …

Superior Sodium-Ion Storage Performance Of Co3o4@Nitrogen-Doped Carbon: Derived From A Metal–Organic Framework, Ying Wang, Caiyun Wang, Yijing Wang, Hua-Kun Liu, Zhenguo Huang

Australian Institute for Innovative Materials - Papers

Nitrogen-doped carbon coated Co 3 O 4 nanoparticles (Co 3 O 4 @NC) with high Na-ion storage capacity and unprecedented long-life cycling stability are reported in this paper. The Co 3 O 4 @NC was derived from a metal – organic framework ZIF-67, where the Co ions and organic linkers were, respectively, converted to Co 3 O 4 nanoparticle cores and nitrogen-doped carbon shells through a controlled two-step annealing process. The Co 3 O 4 @NC shows a porous nature with a surface area of 101 m 2 g 1 . When applied as an anode for sodium ion batteries …

Floating Constructed Wetland For The Treatment Of Polluted River Water: A Pilot Scale Study On Seasonal Variation And Shock Load, Tanveer Saeed, Biprojit Paul, Rumana Afrin,, Abdullah Al-Muyeed, Guangzhi Sun

Research outputs 2014 to 2021

This paper reports the performance of a pilot scale floating constructed wetland (FCW), employed for the treatment of polluted water collected from Buriganga river in Bangladesh. The FCW system included a tank for accommodating collected water and a floating mat with media, to support the growth of two macrophyte species Phragmites australis and Canna indica. Mean mass removal rates of 0.66, 0.76, 0.08, 0.51, 2.49g/m2d were achieved for ammoniacal nitrogen (NH4-N), total inorganic nitrogen (TIN), phosphorus (P), biochemical oxygen demand (BOD), chemical oxygen demand (COD), respectively by the FCW. Nitrogen removal was via nitrification-denitrification processes, whereas filtration-sedimentation appeared to influence …

Synthesis Of Nitrogen-Doped Graphene Via Thermal Treatment Of Graphene Oxide Within Methylimidazole And Its Capacitance Performance As Electric Double Layer Capacitor, Md. Monirul Islam, Shaikh Nayeem Faisal, Anup Kumar Roy, Sonia Ansari, Dean Cardillo, Konstantin K. Konstantinov, Enamul Haque

Australian Institute for Innovative Materials - Papers

Nitrogen-doped graphene was successfully synthesised from graphene oxide (GO) and 2-methylimidazole composite via thermal treatment under argon flow at 700oC within 1h. This synthesised N-doped graphene exhibits homogeneous nitrogen doping with concentration of ~5% in three different nitrogen configuration namelypyridinic N, pyrrolic N and graphitic N. The electric double layer capacitor (EDLC) made up with this N-doped graphene showed excellent specific capacitance 274 F/g at current density of 1A/g, which was ~7 times higher than GO. This EDLC capacitor showed excellent cyclic stability up to 5000 cycles with capacity retention of ~91%.

Manganese Dioxide-Anchored Three-Dimensional Nitrogen-Doped Graphene Hybrid Aerogels As Excellent Anode Materials For Lithium Ion Batteries, Zhu Yin Sui, Caiyun Wang, Kewei Shu, Quan-Sheng Yang, Yu Ge, Gordon G. Wallace, Bao Hang Han

Australian Institute for Innovative Materials - Papers

The capacity of manganese dioxide (MnO₂) deteriorates with cycling due to the irreversible changes induced by the repeated lithiation and delithiation processes. To overcome this drawback, MnO₂/nitrogen-doped graphene hybrid aerogels (MNGAs) were prepared via a facile redox process between KMnO₄ and carbon within nitrogen-doped graphene hydrogels. The three-dimensional nitrogen-doped graphene hydrogels were prepared and utilized as matrices for MnO₂ deposition. The MNGAs-120 obtained after a deposition time of 120 min delivered a very high discharge capacity of 909 mA h g^-1 after 200 cycles at a current density of 400 mA g^{-1 …}

Role Of Anions On Structure And Pseudocapacitive Performance Of Metal Double Hydroxides Decorated With Nitrogen-Doped Graphene, Nasir Mahmood, Muhammad Nawaz Tahir, Asif Mahmood, Wenlong Yang, Xingxing Gu, Chuanbao Cao, Yawen Zhang, Yanglong Hou

Australian Institute for Innovative Materials - Papers

Electrochemical capacitors (EC) bear faster charge-discharge; however, their real applications are still on a long away due to lower capacitance and energy densities which mainly arise from simple surface charge accumulation or/and reaction. Here, a novel synthesis strategy was designed to obtain the purposeful hybrids of nickel cobalt double hydroxide (NiCoDH) with genetic morphology to improve their electrochemical performance as electrode of EC. Nanostructures of metal hydroxides were grown on t he nitrogen-doped graphene (NG) sheets by utilizing defects as nucleation sites and their composition was optimized both by tuning the ratio of Ni:Co as well as the counter halogen …

Water Quality Effects Of Cellulosic Biofuel Crops Grown On Marginal Land, Ruoyu Wang

Ruoyu Wang

Diffuse Nutrient Pollution From Residential Catchments, Melissa Rachelle Butcher

USF Tampa Graduate Theses and Dissertations

Nonpoint source nutrient pollution is diffuse pollution lacking discrete origin and conveyance. This thesis synthesizes and critically reviews research on residential nitrogen and phosphorus loss to stormwater runoff and leaching. The evaluation pulls from research covering influential socio-demographic indicators, such as use of lawn maintenance services and homeowner fertilizer practices. The extent to which such social and economic factors may influence the prevalence and fate of diffuse nutrients in stormwater runoff from residential areas has not been adequately established. Understanding the source and influencing factors of diffuse nutrient pollution is important in order to effectively protect surface and groundwater resources. …

Charged-Controlled Separation Of Nitrogen From Natural Gas Using Boron Nitride Fullerene, Qiao Sun, Caixia Sun, Aijun Du, Zhen Li

Australian Institute for Innovative Materials - Papers

Natural gas (the main component is methane) has been widely used as a fuel and raw material in industry. Removal of nitrogen (N₂) from methane (CH₄) can reduce the cost of natural gas transport and improve its efficiency. However, their extremely similar size increases the difficulty of separating N₂ from CH₄. In this study, we have performed a comprehensive investigation of N₂ and CH₄ adsorption on different charge states of boron nitride (BN) nanocage fullerene, B₃₆N₃₆, by using a density functional theory approach. The calculational results indicate …

Atmospheric Pressure He-Air Plasma Jet: Breakdown Process And Propagation Phenomenon, Asma Begum, Mounir Laroussi, Mohammad Rasel Pervez

Electrical & Computer Engineering Faculty Publications

In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet …

Nitrogen Removal From Natural Gas Using Solid Boron: A First-Principles Computational Study, Qiao Sun, Meng Wang, Zhen Li, Ping Li, Weihua Wang, Xiaojun Tan, Aijun Du

Australian Institute for Innovative Materials - Papers

Selective separation of nitrogen (N2) from methane (CH4) is highly significant in natural gas purification, and it is very challenging to achieve this because of their nearly identical size (the molecular diameters of N2 and CH4 are 3.64 Å and 3.80 Å, respectively). Here we theoretically study the adsorption of N2 and CH4 on B12 cluster and solid boron surfaces a-B12 and c-B28. Our results show that these electron-deficiency boron materials have higher selectivity in adsorbing and capturing N2 than CH4, which provides very useful information for experimentally exploiting boron materials for natural gas purification.

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 …

Boron-Nitrogen-Hydrogen (Bnh) Compounds: Recent Developments In Hydrogen Storage, Applications In Hydrogenation And Catalysis, And New Syntheses, Zhenguo Huang, Tom Autrey

Australian Institute for Innovative Materials - Papers

The strong efforts devoted to the exploration of BNH compounds for hydrogen storage have led to impressive advances in the field of boron chemistry. This review summarizes progress in this field from three aspects. It starts with the most recent developments in using BNH compounds for hydrogen storage, covering NH₃BH₃, B₃H₈- containing compounds, and CBN compounds. The following section then highlights interesting applications of BNH compounds in hydrogenation and catalysis. The last part is focused on breakthroughs in the syntheses and discovery of new BNH organic analogues. The role of N-H^{δ+ …}

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 …

Slides: Impacts Of Oil Shale On Carbon Emissions, Jeremy Boak

The Promise and Peril of Oil Shale Development (February 5)

Presenter: Dr. Jeremy Boak, Center for Oil Shale Technology & Research, Colorado School of Mines

43 slides

Characterization Of An N2 Flowing Microwave Post-Discharge By Oes Spectroscopy And Determination Of Absolute Ground-State Nitrogen Atom Densities By Talif, Et. Es-Sebbar, Y. Benilan, A. Jolly, M-C. Gazeau

Dr. Et-touhami Es-sebbar

A flowing microwave post-discharge source sustained at 2.45 GHz in pure nitrogen has been investigated by optical emission spectroscopy (OES) and two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. Variations of the optical emission along the post-discharge (near, pink and late afterglow) have been studied and the gas temperature has been determined. TALIF spectroscopy has been used in the late afterglow to determine the absolute ground-state nitrogen atomic densities using krypton as a reference gas. Measurements show that the microwave flowing post-discharge is an efficient source of N (4S) atoms in late afterglow. In our experimental conditions, the maximum N (4S) density …

Day 3: Friday, August 6, 2004: Air Quality And Energy Resources, University Of Colorado Boulder. Natural Resources Law Center

Energy Field Tour 2004 (August 4-6)

2 pages (includes illustration).

Release And Transport Of Nutrients From Livestock Manure Applied To Pastureland, Michelle L. Soupir, Saied Mostaghimi, Eugene R. Yagow, David H. Vaughan

Michelle L. Soupir

Land applications of manure from confined animal systems and direct deposit by grazing animals are both major sources of nutrients in streams. An understanding of the overland transport mechanisms from land applied waste is needed to improve design of best management practices and modeling of NPS pollution. Release and transport plots were established to study in-field nutrient release and transport from pasturelands receiving phosphorus based livestock waste applications. The release plots determined the concentrations available to be transported to the edge of the field in runoff. Four manure treatments (turkey litter, liquid dairy manure, standard cowpies, and none) and three …

Nozzle Flow With Vibrational Nonequilibrium, John Gary Landry

Mathematics & Statistics Theses & Dissertations

Flow of nitrogen gas through a converging-diverging nozzle is simulated. The flow is modeled using the Navier-Stokes equations that have been modified for vibrational nonequilibrium. The energy equation is replaced by two equations. One equation accounts for energy effects due to the translational and rotational degrees of freedom, and the other accounts for the affects due to the vibrational degree of freedom. The energy equations are coupled by a relaxation time which measures the time required for the vibrational energy component to equilibrate with the translational and rotational energy components. An improved relaxation time is used in this thesis. The …