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

Physical Sciences and Mathematics Commons™

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

Discipline
Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 43441 - 43470 of 294409

Full-Text Articles in Physical Sciences and Mathematics

Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier Apr 2023

Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier

Chemistry Faculty Research & Creative Works

Interstellar Anions Play an Important Role in Astrochemistry as Being Tracers of the Physical and Chemical Conditions in Cold Molecular Clouds and Circumstellar Gas. the Local Thermodynamic Equilibrium is Generally Not Fulfilled in Media Where Anions Are Detected and Radiative and Collisional Data Are Required to Model the Observed Lines. the C2H- Anion Has Not Yet Been Detected in the Interstellar Medium; However, Collisional Data Could Be Used for Non-LTE Models that Would Help in Identifying the Most Intense Lines. for This Purpose, We Have Computed the First 4D Potential Energy Surface (PES) of the C2H--H2 Complex using an Explicitly …

Go to article

Development Of A Biobased Carbon Adsorbent For Treating Emerging Contaminants In Recycled Water On The International Space Station, Savanna Vacek, Madeline Carroll, Gabson Baguma Apr 2023

Development Of A Biobased Carbon Adsorbent For Treating Emerging Contaminants In Recycled Water On The International Space Station, Savanna Vacek, Madeline Carroll, Gabson Baguma

Undergraduate Research Symposium Posters

The International Space Station (ISS) operates as a closed system. Water is recycled from humidity and urine and held in a wastewater tank; part of the Water Processing Assembly (WPA). Potable treated water is used indirectly in the Sabatier Reactor.The Sabatier Reactor is a key component in the Environmental Control and Life Support System (ECLSS). Three main functions of ECLSS: water recovery, air revitalization, and oxygen generation Sabatier Reactor recently failed due to contamination of DMSO2, dimethyl sulfone, and DMSD, dimethylsilanediol. DMSO2 and DMSD are emerging contaminants that are not removed by the media used in the WPA due to …

Go to article

A Preliminary Evaluation Method For Coal-Based Graphite, Liu Kang, Ning Shuzheng, Cao Daiyong, Wu Guoqiang, Wang Lu, Lin Zhongyue, Wang Anmin Apr 2023

A Preliminary Evaluation Method For Coal-Based Graphite, Liu Kang, Ning Shuzheng, Cao Daiyong, Wu Guoqiang, Wang Lu, Lin Zhongyue, Wang Anmin

Coal Geology & Exploration

Coal-based graphite is a type of strategic mineral resource and has unique advantages in the fields such as nuclear graphite and military aircraft tires. The evaluation of coal-based graphite is crucial to its exploration and development, upgrading and storage increase, and strategic resource security. Owing to the continuous transition between coal-based graphite and highly metamorphosed coals, some coal-based graphite tends to be wrongly treated as blind coal, and, accordingly, the identified resources of existing coal-based graphite may have been greatly underestimated. In fact, the resources of coal-based graphite are directly related to those of high-rank coals. Therefore, it is significant …

Go to article

Study On Methane Adsorption/Desorption And Flow Law In The Nanopores Of Coal Based On Lammps, Shi Yu, Liu Yang, Xue Junhua, Li Shugang, Zhang Chao Apr 2023

Study On Methane Adsorption/Desorption And Flow Law In The Nanopores Of Coal Based On Lammps, Shi Yu, Liu Yang, Xue Junhua, Li Shugang, Zhang Chao

Coal Geology & Exploration

In this work, the influence rules of driving force, pore size, temperature and pressure on methane adsorption/desorption and flow in coal nanopores were investigated by the molecular dynamic method based on Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The investigation results show that the viscosity of methane gradually decreases with the increasing driving force, while its fluidity and flow velocity increase. Meanwhile, the absolute slip length decreases and the flow tends to the non-slip state. Generally, the adsorption density of methane is independent of the driving force, but greatly affected by the gas-solid action. Methane can be adsorbed on the pore …

Go to article

Application Of Ecological Geological Layer Theory In Coal Seam Protection And Ecological Restoration—An Example Of Ecological Management Practice In Plateau Alpine Mining Areas, Wang Qingwei, Xing Xiafan, Zou Mingjun, Guo Biao, Zhao Xin, Wang Tong Apr 2023

Application Of Ecological Geological Layer Theory In Coal Seam Protection And Ecological Restoration—An Example Of Ecological Management Practice In Plateau Alpine Mining Areas, Wang Qingwei, Xing Xiafan, Zou Mingjun, Guo Biao, Zhao Xin, Wang Tong

Coal Geology & Exploration

The ecological management of alpine permafrost area in plateau is a global problem, with few precedents for coal resource protection while ecological management. In this paper, the following results achieved in the ecological management in Muli area of Qinghai Province were understood in accordance with the idea of systematic engineering for the purpose of ecological environmental protection, with consideration to the protection of residual coal resources. Specifically, study was conducted on the ecological vulnerability of Muli mining area to damage and the difficulty of restoration under the control of natural climatic characteristics. Meanwhile, the characteristics of soil erosion and vegetation …

Go to article

Processing Of Coal Mine Csamt Data With Wide Field Electromagnetic Method, Zhu Yunqi, Li Diquan, Liu Zuiliang, Zhang Xin Apr 2023

Processing Of Coal Mine Csamt Data With Wide Field Electromagnetic Method, Zhu Yunqi, Li Diquan, Liu Zuiliang, Zhang Xin

Coal Geology & Exploration

A CSAMT detection test was carried out for a coal mine with V8 multi-functional electrical instrument. Due to the serious electromagnetic interference within the area, the Cagniard apparent resistivity was low in quality. In order to improve the quality and utilization rate of data, authors attempted to process the CSAMT data collected by V8 with the wide field electromagnetic method, which used single-component method and ratio method (Electric field divided by magnetic field) to calculate apparent resistivity. The results showed that there was some deviation between the single-component wide field apparent resistivity and the actual terrestrial electricity because the emission …

Go to article

Experimental Study On Heat Transfer Performance Of Double U-Shaped Buried Tube Heat Exchanger, Li Lei, Zhang Weidong, Xu Shuanhai, Zhao Yongzhe, Dang Dongsheng, Wang Qilong, Gou Li, Lei Yanzi Apr 2023

Experimental Study On Heat Transfer Performance Of Double U-Shaped Buried Tube Heat Exchanger, Li Lei, Zhang Weidong, Xu Shuanhai, Zhao Yongzhe, Dang Dongsheng, Wang Qilong, Gou Li, Lei Yanzi

Coal Geology & Exploration

Double U-shaped buried tube heat exchanger (DUBTHE) are prone to pipe crossing and thermal short-circuiting in the practical applications, resulting in the reduced heat transfer performance and directly affecting the operational efficiency of shallow geothermal heat pump system. Based on the initial line thermal average temperature, thermal conductivity theory and slope method, and taking a shallow geothermal heat pump project in Xi'an as the engineering background. Then, this study investigate the effects of initial average temperature, thermal conductivity and volumetric heat capacity of rock-soil, and tube clamp spacing on the heat transfer performance of DUBTHE through field geotechnical thermal response …

Go to article

Quality Assessment Of Resistivity Monitoring Data Of Coal Mines, Cui Weixiong, Yuan Bo Apr 2023

Quality Assessment Of Resistivity Monitoring Data Of Coal Mines, Cui Weixiong, Yuan Bo

Coal Geology & Exploration

Resistivity monitoring of coal mines is an important technical means of preventing water hazards on the roof and floor of a mining face. However, it is difficult to guarantee high-quality resistivity data monitored and collected due to the complex and extremely strong electromagnetic interference in the monitoring environment, as well as the limitations of the maximum emission current for the purpose of safe coal mining. To select and utilize highly reliable data from the massive data monitored daily, this study compared and analyzed the advantages and disadvantages of commonly used methods for quality assessment of data obtained using the DC …

Go to article

Key Technology Of Automatic Loading And Unloading System For Dual-Pipe Directional Drilling Rig And Its Application In Soft–Fragmentized Coal Seam, Li Kun, Ting Ren, Yao Yafeng Apr 2023

Key Technology Of Automatic Loading And Unloading System For Dual-Pipe Directional Drilling Rig And Its Application In Soft–Fragmentized Coal Seam, Li Kun, Ting Ren, Yao Yafeng

Coal Geology & Exploration

To improve the automatic level and efficiency of loading and unloading of drilling rigs during the construction of dual-pipe directional drilling, an automatic loading and unloading device of dual pipe was developed to realize the fully automatic loading and unloading of drilling rigs under different working conditions and to solve the technical problems of loading and unloading the drill pipes and casing simultaneously during the dual-pipe directional drilling. Meanwhile, the device structure and control system was designed to restrict the load applied to the device during construction with the end-compliant technique. Besides, the key boundary conditions of the control program …

Go to article

Effects Of Mos2 On The Matrix Performance Of Hot-Pressed Fe-Based Diamond Drill Bit, Zhang Wenjiao, Tan Songcheng, Pan Bingsuo, Jin Xin, Kong Xiangqing, Long Shanglin Apr 2023

Effects Of Mos2 On The Matrix Performance Of Hot-Pressed Fe-Based Diamond Drill Bit, Zhang Wenjiao, Tan Songcheng, Pan Bingsuo, Jin Xin, Kong Xiangqing, Long Shanglin

Coal Geology & Exploration

Diamond drill bit is a common rock breaking tool in various exploration works, but the diamond in drill bit has poor thermal stability. As heat is constantly generated during the drilling process, the self-cooling of diamond drill bit under the condition of drought and water shortage is very important to improve the drilling efficiency. In order to decrease the friction coefficient between bit matrix and rock interface under dry drilling condition and reduce the thermal damage of diamond during drilling, molybdenum disulfide (MoS2) was added into the Fe-based diamond bit matrix, and research was performed for the effects …

Go to article

Study On Construction Of Microbial Solid-Free Drilling Fluid System And Its Borehole Wall Enhancement Mechanism, Li Zhijun, Zhu Mao, Zhi Jingzi, Han Yi, Chen Junxiu, Zhao Gan Apr 2023

Study On Construction Of Microbial Solid-Free Drilling Fluid System And Its Borehole Wall Enhancement Mechanism, Li Zhijun, Zhu Mao, Zhi Jingzi, Han Yi, Chen Junxiu, Zhao Gan

Coal Geology & Exploration

Broken formations are often encountered during drilling, which is prone to the instability of wellbore wall and induces serious downhole accidents. Enhancing the cementing force between the broken blocks and improving the mechanical strength of the surrounding rocks of a wellbore is one of the effective ways to solve the instability of wellbore in this type of formation, for which the microbially induced calcite precipitation (MICP) technology provides a good reference. To this end, the growth of Bacillus pasteurii in the solid-free drilling fluid system was analyzed through experimental study, and thus a solid-free drilling fluid suitable for its growth …

Go to article

Developing Weak Galerkin Finite Element Methods, Ahmed Sallal Joudah Al-Taweel Apr 2023

Developing Weak Galerkin Finite Element Methods, Ahmed Sallal Joudah Al-Taweel

Theses and Dissertations

The weak Galerkin finite element method is a flexible and effective numerical technique for solving partial differential equations (PDEs). The goal of this dissertation is to develop new weak Galerkin schemes for solving PDEs on uniform triangular partitions in 2D. These schemes will improve the efficiency of the weak Galerkin method and avoiding numerical locking. First, we investigate the lowest-order weak Galerkin finite element method for solving reaction-diffusion equations with singular perturbations. Then, we propose a weak Galerkin method for the Laplace equation using harmonic polynomial finite elements instead of the full polynomial space $P_k$ to achieve the same order …

Go to article

Head And Neck Tumor Histopathological Image Representation With Pre- Trained Convolutional Neural Network And Vision Transformer, Ranny Rahaningrum Herdiantoputri, Daisuke Komura, Tohru Ikeda, Shumpei Ishikawa Apr 2023

Head And Neck Tumor Histopathological Image Representation With Pre- Trained Convolutional Neural Network And Vision Transformer, Ranny Rahaningrum Herdiantoputri, Daisuke Komura, Tohru Ikeda, Shumpei Ishikawa

Journal of Dentistry Indonesia

Image representation via machine learning is an approach to quantitatively represent histopathological images of head and neck tumors for future applications of artificial intelligence-assisted pathological diagnosis systems. Objective: This study compares image representations produced by a pre-trained convolutional neural network (VGG16) to those produced by a vision transformer (ViT-L/14) in terms of the classification performance of head and neck tumors. Methods: W hole-slide images of five oral t umor categories (n = 319 cases) were analyzed. Image patches were created from manually annotated regions at 4096, 2048, and 1024 pixels and rescaled to 256 pixels. Image representations were …

Go to article

Table Of Contents, The Editors Apr 2023

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Go to article

Effect Of Amf-Maize Combination On Water And Salt Distribution In Soil Under The Dump Reconstruction Mode Of “Topsoil-Aquifer-Aquitard”, Bi Yinli, Yang Wei, Ke Zengming, Wu Chao, Li Mingchao, Xue Chao Apr 2023

Effect Of Amf-Maize Combination On Water And Salt Distribution In Soil Under The Dump Reconstruction Mode Of “Topsoil-Aquifer-Aquitard”, Bi Yinli, Yang Wei, Ke Zengming, Wu Chao, Li Mingchao, Xue Chao

Coal Geology & Exploration

The distribution of soil water and salt severely affects the ecological reconstruction and plant configuration modes at coal mine dumps. To investigate the characteristics of soil water and salt distribution under the three-layer reconstruction mode of “topsoil-aquifer-aquitard” in coal mine dump under the influence of mycorrhizal plants, laboratory soil column test was conducted, in which the soil was treated in three ways: planting maize and inoculating with arbuscular mycorrhizal fungi (YM+AMF), planting maize (YM) only, and no planting of maize + no inoculation with bacteria (CK). The results showed that: (1) The different treatments have no significant effect on the …

Go to article

Effects Of Actinomycetes On Root Growth Of Onobrychis Viciaefolia And Rhizosphere Soil Fertility In Dumping Site Of Open-Pit Mine In Arid Area, Cao Shumiao, Wang Qiangmin, Yang Fan, Yang Jian, Zhang Haihan, Xu Ganggang, Zhu Shibin Apr 2023

Effects Of Actinomycetes On Root Growth Of Onobrychis Viciaefolia And Rhizosphere Soil Fertility In Dumping Site Of Open-Pit Mine In Arid Area, Cao Shumiao, Wang Qiangmin, Yang Fan, Yang Jian, Zhang Haihan, Xu Ganggang, Zhu Shibin

Coal Geology & Exploration

In order to resolve the issue of soil degradation in the dumping site of open-pit coal mine in arid area, the effects of actinomycetes on the root growth and rhizosphere soil fertility of onobrychis viciaefolia in the dumping site of Xinjiang Heishan Open-pit Coal Mine were investigated by highly efficient actinomycete inoculation and in-situ pot experiment. The results show that: (1) Under the drought conditions, actinomycetes inoculation could significantly promote the development of root morphology and the growth of onobrychis viciaefolia. Compared with the control without actinomycetes inoculation, the total root length, average root diameter, root surface area and …

Go to article

Constraining H0 Via Extragalactic Parallax, Nicholas Ferree Apr 2023

Constraining H0 Via Extragalactic Parallax, Nicholas Ferree

Honors Theses

We examine the prospects for measurement of the Hubble parameter 𝐻0 via observation of the secular parallax of other galaxies due to our own motion relative to the cosmic microwave background rest frame. Peculiar velocities make distance measurements to individual galaxies highly uncertain, but a survey sampling many galaxies can still yield a precise 𝐻0 measurement. We use both a Fisher information formalism and simulations to forecast errors in 𝐻0 from such surveys, marginalizing over the unknown peculiar velocities. The optimum survey observes ∼ 102 galaxies within a redshift 𝐻0max = 0.06. The required errors …

Go to article

The 2015 Ncaa Cost-Of-Attendance Stipend And Its Effects On Institutional Financial Aid Packages, Sara Greene Apr 2023

The 2015 Ncaa Cost-Of-Attendance Stipend And Its Effects On Institutional Financial Aid Packages, Sara Greene

Honors Theses

In 2015, the National Collegiate Athletic Association (NCAA) allowed “Cost of Attendance” (COA) stipends to be offered to athletic recruits for Division I schools. These stipends are intended to allow schools to grant aid to student-athletes beyond a full-ride scholarship to cover additional costs imposed on student-athletes. These stipends created an opportunity for the “Autonomy” Power 5 programs to utilize a competitive tactic to try to win over the top recruits. There is evidence that these COA stipends have caused an increase in the estimated cost of attendance reported by the university. This paper examines if the COA stipends have …

Go to article

Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen Apr 2023

Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen

Honors Theses

At Jefferson Lab we use the CLAS12 detector to measure the neutron magnetic form factor. An accurate measurement of the CLAS12 neutron detection efficiency (NDE) is required. We use the nuclear reaction ���� → ��′��+�� as a source of tagged neutrons and obtain the NDE from the ratio of expected neutrons to detected ones. We assume the final state consists of ��′��+�� only, use the ��′��+ information to predict the neutron's position(expected) and then search for that neutron(detected). We select neutrons with the missing mass (MM) technique. We use simulation to validate our methods. We simulated events with the Monte-Carlo …

Go to article

The Parental Labor Gap: The Impact Of Daycare Access On The Parental Labor Force During The Covid-19 Pandemic, Acacia Wyckoff Apr 2023

The Parental Labor Gap: The Impact Of Daycare Access On The Parental Labor Force During The Covid-19 Pandemic, Acacia Wyckoff

Honors Theses

In the two years since the COVID-19 pandemic began, the landscape for work has shifted dramatically. Many companies and employers switched to telework when the pandemic hit, and many still do not require workers to come into the office. Research suggests these COVID-induced changes have led to a closing of the gap in childcare duties between men and women in households. Comparing parents in positions with telework eligibility versus in-person positions, Heggeness and Suri (2022) found that while telework improved the labor participation rate of mothers slightly, there was still a major gap in labor force participation between mothers and …

Go to article

Synthesis And Characterization Of Rhenium 2,2′-Pyridylnaphthyridine Metal Complexes, Benjamin F. Solomon Apr 2023

Synthesis And Characterization Of Rhenium 2,2′-Pyridylnaphthyridine Metal Complexes, Benjamin F. Solomon

Honors Theses

Rhenium (Re) is a group 7 heavy 5d transition metal in the same family as manganese (Mn) and technetium (Tc). Re-carbonyl complexes are known to be catalysts for many different kinds of reactions from C-C bond formation to reduction reactions like CO2 reduction (CO2RR)1,2. With this in mind, we have prepared a set of six Re-carbonyl complexes of 2,2′-pyridyl-1,6-naphthyridine (1,6- pynap) and 2,2′-pyridyl-1,8-naphthyridine (1,8-pynap), a redox non-innocent ligand containing a bpy moiety as well as an additional aryl nitrogen binding location at which another metal-ligand bond could form. We have synthesized these complexes as precursors …

Go to article

Cobalt/Carbon Composites As Sulfur Hosts For High-Performance Lithium-Sulfur Batteries, Yun-Rui Yang, Huan-Huan Dong, Zhi-Qiang Hao, Xiang-Xi He, Zhuo Yang, Lin Li, Shu-Lei Chou Apr 2023

Cobalt/Carbon Composites As Sulfur Hosts For High-Performance Lithium-Sulfur Batteries, Yun-Rui Yang, Huan-Huan Dong, Zhi-Qiang Hao, Xiang-Xi He, Zhuo Yang, Lin Li, Shu-Lei Chou

Journal of Electrochemistry

Lithium-sulfur (Li-S) battery is one of the promising energy storage devices because of its high energy density. However, the sulfur cathode suffers from sluggish electrochemical reaction kinetics, slow charge transfer, large volume expansion and severe shuttle effect of lithium polysulfides inevitably resulting in low reversible capacity, poor rate performance and short cycle life, limiting its practical applications. Herein, the recent progress of cobalt/carbon composites, including cobalt nanoparticles and cobalt single atoms, as the sulfur host materials in Li-S batteries is overviewed. In general, cobalt plays the role of electrocatalyst, which inhibits the shuttle effect of lithium polysulfides, accelerates the electrochemical …

Go to article

Recent Advances Of Functional Electrolyte Additives For Lithium-Sulfur Batteries, Xiu-Qing Zhang, Shuai Tang, Yong-Zhu Fu Apr 2023

Recent Advances Of Functional Electrolyte Additives For Lithium-Sulfur Batteries, Xiu-Qing Zhang, Shuai Tang, Yong-Zhu Fu

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries have become one of the most promising next-generation battery systems due to their high energy density and low cost. However, the application of Li-S batteries still faces critical challenges, such as the low conductivities of S and Li2S, shuttle effect of polysulfides and dendrite growth of Li, etc. The optimization of the electrolyte can ameliorate the electrolyte|electrode interphase, conveniently regulating the parasitic reaction and improving the performance of the resultant batteries. The functional additives in electrolytes provide chances to tune the interphase and even the redox mechanism to improve the performance of the batteries. In …

Go to article

Ultraviolet-Initiated In-Situ Cross-Linking Of Multifunctional Binder Backbones Enables Robust Lithium-Sulfur Batteries, Sha Li, Xiao Zhan, Gu-Lian Wang, Hui-Qun Wang, Wei-Ming Xiong, Li Zhang Apr 2023

Ultraviolet-Initiated In-Situ Cross-Linking Of Multifunctional Binder Backbones Enables Robust Lithium-Sulfur Batteries, Sha Li, Xiao Zhan, Gu-Lian Wang, Hui-Qun Wang, Wei-Ming Xiong, Li Zhang

Journal of Electrochemistry

Lithium-sulfur (Li-S) batteries show attractive prospects owing to their high theoretical energy density, but their commercialization still faces such challenges as lithium polysulfides shuttling, severe volume change and considerable polarization. These stubborn issues place higher demands on each component in the battery, such as the development of multifunctional binders with superior mechanical properties. Herein, ethoxylated trimethylolpropane triacrylate was firstly introduced into sulfur cathodes, and in-situ cross-linked by ultraviolet (UV) curing combined with traditional polyvinylidene difluoride binder (i.e., forming a binary binder, denoted as c-ETPTA/PVDF) to construct high-loading and durable Li-S batteries. The covalently cross-linked ETPTA framework not only significantly enhances …

Go to article

Metals And Alloys As Catalytic Hosts Of Sulfur Cathode For Lithium-Sulfur Batteries, Zhen-Yu Wang, Xue-Ping Gao Apr 2023

Metals And Alloys As Catalytic Hosts Of Sulfur Cathode For Lithium-Sulfur Batteries, Zhen-Yu Wang, Xue-Ping Gao

Journal of Electrochemistry

Lithium-sulfur batteries are recognized as one of the most promising next-generation energy storage devices, owing to the high theoretical energy density of 2600 Wh·kg–1. However, their application has been seriously hindered by the sluggish electrochemical reaction kinetics of elemental sulfur and discharged products (Li2S2/Li2S), and the notorious “shuttle effect” of soluble intermediate lithium polysulfide species, leading to poor cycle stability, low sulfur utilization and inferior coulombic efficiency. Introducing catalytic hosts into sulfur cathode is an efficient path to propel the conversion of sulfur-contained species, thus preventing the dissolution and loss of active-sulfur …

Go to article

Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin Apr 2023

Preface To The Special Issue On Lithium-Sulfur Batteries, Jia-Jia Chen, Ren-Jie Chen, Zhong Jin

Journal of Electrochemistry

No abstract provided.

Go to article

Synthesis Of 2-Bromo-6-Alkylaminopyridines, 2,6-Dialkylaminopyridines, And Tren Based Ligands, Stephanie E. Carter Apr 2023

Synthesis Of 2-Bromo-6-Alkylaminopyridines, 2,6-Dialkylaminopyridines, And Tren Based Ligands, Stephanie E. Carter

Honors College Theses

Extended metal atom chains (EMAC) are multimetallic complexes that feature a linear metal chain with metal-metal bonds surrounded by stabilizing ligand molecules. When EMACs are formed with paramagnetic metal ions, unique magnetic properties can be derived from direct metal to metal communication. The challenge is that EMAC complexes are challenging to synthesize due to the inherent weakness of most M-M bonds and the specificity of the ligands required to stabilize EMACs. In prior work by the Guillet group, the silyl aminopyridine (SAP) ligands were observed to stabilize very unique triiron complexes, but they were inherently unstable. In other work, scaffolded …

Go to article

The Forest Of Claytor Nature Center As A Carbon Offset; Assessing The Sequestration Potential And Socioeconomic Implications, Sarah Mccollum Apr 2023

The Forest Of Claytor Nature Center As A Carbon Offset; Assessing The Sequestration Potential And Socioeconomic Implications, Sarah Mccollum

Graduate Dissertations and Theses

Cap and trade programs limit the amount of emissions an organization can produce. To neutralize unavoidable emissions, organizations can purchase carbon offsets from the carbon market. The ability to quantify greenhouse gas emissions offsets in forests increased the urgency and popularity of the carbon market because carbon dioxide (CO2) has a large role in climate change. The University of Lynchburg’s Claytor Nature Center’s 332-acre forest could be a viable revenue source because of its ability to remove CO2 from the atmosphere. In this research, the potential number of annual offsets from Claytor Forest was measured through a manual biomass survey. …

Go to article

Comparing Igneous Geochemical Data From Hawaii And Southern California Via Machine Learning, Miro Manestar Apr 2023

Comparing Igneous Geochemical Data From Hawaii And Southern California Via Machine Learning, Miro Manestar

MS in Computer Science Project Reports

Bi-plots are commonly used in geochemical analyses. However, their use can become cumbersome in the case of multi-variate analyses. Therefore, this thesis explores the application of unsupervised machine learning techniques, specifically PCA and K-Means, to analyze large geochemical data sets from two distinct regions, Hawaii and the \acrfull{prb} in Southern California. The IBM Foundational Methodology for Data Science was utilized to ensure proper data preparation and analysis. PCA provided dimensionality reduction, revealing which features correlated most strongly with variances within the data. K-Means clustering allowed for deeper interpretation of the data. The analysis yielded valuable insights into the composition and …

Go to article

Brown Carbon From Photo-Oxidation Of Glyoxal And So2 In Aqueous Aerosol, David O. De Haan, Lelia N. Hawkins, Praveen D. Wickremasinghe, Alyssa D. Andretta, Juliette R. Dignum, Audrey C. De Haan, Hannah G. Welsh, Elyse A. Pennington, Tianqu Cui, Jason D. Surratt, Mathieu Cazaunau, Edouard Pangui, Jean-François Doussin Apr 2023

Brown Carbon From Photo-Oxidation Of Glyoxal And So2 In Aqueous Aerosol, David O. De Haan, Lelia N. Hawkins, Praveen D. Wickremasinghe, Alyssa D. Andretta, Juliette R. Dignum, Audrey C. De Haan, Hannah G. Welsh, Elyse A. Pennington, Tianqu Cui, Jason D. Surratt, Mathieu Cazaunau, Edouard Pangui, Jean-François Doussin

Chemistry and Biochemistry: Faculty Scholarship

Aqueous-phase dark reactions during the co-oxidation of glyoxal and S(IV) were recently identified as a potential source of brown carbon (BrC). Here, we explore the effects of sunlight and oxidants on aqueous solutions of glyoxal and S(IV), and on aqueous aerosol exposed to glyoxal and SO2. We find that BrC is able to form in sunlit, bulk-phase, sulfite-containing solutions, albeit more slowly than in the dark. In more atmospherically relevant chamber experiments where suspended aqueous aerosol particles are exposed to gas-phase glyoxal and SO2, the formation of detectable amounts of BrC requires an OH radical source …

Go to article

First Prev Next Last