Academic literature on the topic 'Sulfur Dot'
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Journal articles on the topic "Sulfur Dot"
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Li, Xueliang, Kuan Hu, Ruwen Tang, Kun Zhao, and Yunsheng Ding. "CuS quantum dot modified carbon aerogel as an immobilizer for lithium polysulfides for high-performance lithium–sulfur batteries." RSC Advances 6, no. 75 (2016): 71319–27. http://dx.doi.org/10.1039/c6ra11990e.
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CuS quantum dot (QD) modified carbon aerogels were successfully prepared via a facile and scalable method to encapsulate sulfur and polysulfides into the hierarchical porous channel of lithium–sulfur batteries.
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Brubaker, Cole D., Talitha M. Frecker, James R. McBride, Kemar R. Reid, G. Kane Jennings, Sandra J. Rosenthal, and Douglas E. Adams. "Incorporation of fluorescent quantum dots for 3D printing and additive manufacturing applications." Journal of Materials Chemistry C 6, no. 28 (2018): 7584–93. http://dx.doi.org/10.1039/c8tc02024h.
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Jian, Zhixu, Shichao Zhang, Xianggang Guan, Jiajie Li, Honglei Li, Wenxu Wang, Yalan Xing, and Huaizhe Xu. "ZnO quantum dot-modified rGO with enhanced electrochemical performance for lithium–sulfur batteries." RSC Advances 10, no. 54 (2020): 32966–75. http://dx.doi.org/10.1039/d0ra04986g.
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Veamatahau, Aisea, Bo Jiang, Tom Seifert, Satoshi Makuta, Kay Latham, Masayuki Kanehara, Toshiharu Teranishi, and Yasuhiro Tachibana. "Origin of surface trap states in CdS quantum dots: relationship between size dependent photoluminescence and sulfur vacancy trap states." Physical Chemistry Chemical Physics 17, no. 4 (2015): 2850–58. http://dx.doi.org/10.1039/c4cp04761c.
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Luo, Zhimin, Dongliang Yang, Guangqin Qi, Jingzhi Shang, Huanping Yang, Yanlong Wang, Lihui Yuwen, Ting Yu, Wei Huang, and Lianhui Wang. "Microwave-assisted solvothermal preparation of nitrogen and sulfur co-doped reduced graphene oxide and graphene quantum dots hybrids for highly efficient oxygen reduction." J. Mater. Chem. A 2, no. 48 (2014): 20605–11. http://dx.doi.org/10.1039/c4ta05096g.
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Yang, Ze, Juan Xiao, Jia-Yun Wan, Zhong-Guo Liu, Ting-Ting Cao, Wen-Jie Zhang, and Hang-Xing Wang. "Graphene oxide/carbon dot composite: a new photoelectrode material for photocurrent response enhancement." Physical Chemistry Chemical Physics 17, no. 48 (2015): 32283–88. http://dx.doi.org/10.1039/c5cp05616k.
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Yuan, Mingjian, Kyle W. Kemp, Susanna M. Thon, Jin Young Kim, Kang Wei Chou, Aram Amassian, and Edward H. Sargent. "High-Performance Quantum-Dot Solids via Elemental Sulfur Synthesis." Advanced Materials 26, no. 21 (March 21, 2014): 3513–19. http://dx.doi.org/10.1002/adma.201305912.
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Al Ghifari, Alvin Dior, Edi Sanjaya, and Isnaeni Isnaeni. "Pengaruh Doping Nitrogen, Sulfur, dan Boron terhadap Spektrum Absorbansi dan Fotoluminesensi Karbon Dot Asam Sitrat." Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics 2, no. 2 (December 31, 2019): 93–101. http://dx.doi.org/10.15408/fiziya.v2i2.11787.
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Telah dilakukan sintesis karbon dot dengan bahan asam sitrat dengan metode pemanasan microwave. Sampel yang dibuat adalah sampel murni dan sampel yang diberi doping. Doping yang digunakan adalah HNO3 untuk doping Nitrogen (N), Na2S2O5 untuk doping Sulfur (S), dan H3BO3 untuk doping Boron (B). Pengujian optik yang dilakukan adalah Absorbansi UV-Vis dan Fotoluminesensi. Sampel karbon dot asam sitrat tanpa doping diuji terlebih dahulu, kemudian karbon dot doping-N, doping-S, dan doping-B diuji. Hasil yang didapat berupa spektrum absorbansi yang merupakan daya serap gelombang sampel yang diuji, dan spektrum fotoluminesensi yang merupakan pendaran sampel yang diuji. Spektrum sebelum pendopingan dibandingkan dengan spektrum setelah pendopingan. Dilakukan analisis perubahan sumbu-x yaitu pergeseran panjang gelombang, dan sumbu-y yaitu kenaikan atau penurunan nilai absorbansi dan intensitas fotoluminesensi. Hasil absorbansi karbon dot asam sitrat murni memiliki dua buah puncak (peak) absorbansi. Pendopingan N dan S tidak mempengaruhi spektrum absorbansi secara signifikan, namun pendopingan B sangat mempengaruhinya pada puncak kedua dengan menggeser 40 nm ke kanan dan menurunkan nilai absorbansi 1,68. Sedangkan hasil fotoluminesensi karbon dot asam sitrat murni memiliki sebuah puncak pada panjang gelombang 502 nm dengan intensitas 758 a.u., atau pendarannya berada dalam daerah warna cyan. Pendopingan N, S, dan B dapat menggeser spektrum fotoluminesensi ke arah warna merah dan nilai terbesar adalah dengan doping S yaitu sebesar 32 nm.
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Rasal, Akash S., Khalilalrahman Dehvari, Girum Getachew, Chiranjeevi Korupalli, Anil V. Ghule, and Jia-Yaw Chang. "Efficient quantum dot-sensitized solar cells through sulfur-rich carbon nitride modified electrolytes." Nanoscale 13, no. 11 (2021): 5730–43. http://dx.doi.org/10.1039/d0nr07963d.
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Polysulfide electrolytes with sulfur-rich graphitic carbon nitride additives are effective in various Cu-based I–III–VI quantum dot-sensitized solar cells, including Cu–In–S and Cu–In–Se, for improving power conversion efficiencies.
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Meng, Fanrong, Haoran Xu, Shuolin Wang, Jingxian Wei, Wengong Zhou, Qiang Wang, Peng Li, Fangong Kong, and Yucang Zhang. "One-step high-yield preparation of nitrogen- and sulfur-codoped carbon dots with applications in chromium(vi) and ascorbic acid detection." RSC Advances 12, no. 30 (2022): 19686–94. http://dx.doi.org/10.1039/d2ra01758j.
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A novel bio-based nitrogen- and sulfur-codoped carbon dot with enhanced synthetic yield and photoluminescence quantum yield for reversible detection of chromium (Cr)(vi) and ascorbic acid was fabricated by a one-pot hydrothermal method.
Dissertations / Theses on the topic "Sulfur Dot"
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Damian, Risberg Emiliana. "Structure and bonding of sulfur-containing molecules and complexes." Doctoral thesis, Stockholms universitet, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6843.
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Synchrotron-based spectroscopic techniques enable investigations of the many important biological and environmental functions of the ubiquitous element sulfur. In this thesis the methods for interpreting sulfur K-edge X-ray absorption near edge structure (XANES) spectra are developed and applied for analyses of functional sulfur groups. The influence of coordination, pH, hydrogen bonding, etc., on the sulfur 1s electronic excitations is evaluated by transition potential density functional theory. Analyses have been performed of reduced sulfur compounds in marine-archaeological wood from historical shipwrecks, including the Vasa, Stockholm, Sweden and the Mary Rose, Portsmouth, U.K.. The accumulation of sulfur as thiols in lignin-rich parts of the wood on the seabed is also a probable pathway in the natural sulfur cycle for how reduced sulfur enters fossil fuels via humic matter in anaerobic marine sediments. Sulfur K-edge XANES spectra for several biochemical model compounds and for coexisting isomeric sulfur species in cysteine and sulfite(IV) aqueous solutions have been analyzed with the aid of theoretical calculations. Cysteine derivatives are important for biochemical detoxification, and mercury(II) cysteine complexes in solution have been structurally characterized by means of Extended X-ray Absorption Fine Structure (EXAFS), Raman and 199Hg NMR spectroscopy. Lanthanoid(III) ions were found to coordinate eight dimethyl sulfoxide oxygen atoms in a distorted square antiprism in the solid state and in solution, by combining crystallography, EXAFS, XANES and vibrational spectroscopy. The mean M-O bond distances for the disordered crystal structures are in good agreement with those from the lattice-independent EXAFS studies. The different sulfur K-edge XANES spectra for the dimethyl sulfoxide ligands in the hexasolvated complexes of the trivalent group 13 metal ions, Tl(III), In(III), Ga(III) and Al(III), were interpreted by theoretical calculations.
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Straistari, Tatiana. "Synthesis and study of coordination compounds of cobalt, copper, palladium and nickel with polydentate ligands containing sulfur." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4352.
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Ce travail porte sur la synthèse, la caractérisation et l’évaluation en catalyse de réduction des protons en dihydrogène, de nouveaux complexes de Ni(II), Co(III), Cu(II) et Pd(II) basés sur des ligands de type thiosemicarbazone. La nature de l’espèce catalytique active a été étudiée par voltampérométrie cyclique et des propositions de mécanisme ont été formulés sur la base de calcul quantique de type DFT.Le premier chapitre introduit le contexte scientifique. Le second chapitre concerne la synthèse et la caractérisation des ligands de type N2S2 et des complexes mononucléaires associés de Ni, Cu et Pd. Le troisième chapitre présente la synthèse et la caractérisation de complexes binucléaires de Co et trinucléaire de Ni.Les études électrochimiques de ces complexes dans le DMF en présence d’une source de protons, nous a permis d’évaluer leur efficacité catalytique. Nos résultats montrent que les complexes du Cu et du Pd présentent une vague irréversible spécifique pour la réduction des protons, mais une décomposition est observée durant l’électrolyse. Par contre, les complexes de Ni et de Co ont montré une stabilité électrochimique ainsi que de bonnes performances catalytiques. En particulier, le nouveau complexe mononucléaire de Ni présente des propriétés catalytiques remarquables qui le classent parmi les meilleurs catalyseurs de la réduction des protons décrits dans la littérature. L’ensemble de ce travail fourni une description complète du comportement électrochimique des ligands de type N2S2 complexés à des métaux de transition. Il permet d’envisager des développements futurs dans l’amélioration des propriétés catalytiques de ces complexesThis work focuses on the synthesis, the characterization and the catalytic evaluation in the reduction of protons into dihydrogen, of new complexes of Ni(II), Co(III), Cu(II) and Pd(II) based ligands Type thiosemicarbazone. The catalytically active species during the process of the proton reduction was studied by cyclic voltammetry and mechanisms were formulated on the basis quantum chemical calculation.The first chapter introduces the scientific context, the goals and the main objectives of this work. The second chapter concerns the synthesis and the characterization of the N2S2 ligands and their associated mononuclear complexes, Ni, Cu and Pd. The third chapter presents the synthesis and the characterization of binuclear Co and trinuclear Ni based on N2S2 ligand.Electrochemical studies of these complexes in DMF in the presence of a proton source (trifluoroacetic acid), allowed us to evaluate their catalytic efficiency. Our results show that Cu and Pd complexes have a specific irreversible wave for the reduction of protons, but decomposition is observed during electrolysis, which makes these uninteresting complexes for the reduction of protons.On the contrary, Ni and Co complexes showed an electrochemical stability and good catalytic performances. In particular, the new mononuclear Ni complex exhibits remarkable catalytic properties that rank it among the best catalysts for the reduction of protons reported in the literature. All this work provided a complete description of the electrochemical behavior of N2S2 thiosemicarbazone ligands complexed to transition metals. It allows considering future developments in improving the catalytic properties of these complexes
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Johansson, Eva. "Samband mellan vulkanutbrott och klimatförändringar : Analys och värdering av teorier om vulkanisk aska och gasers påverkan på det globala klimatet." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-114312.
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This literature review analyses and discusses different theories and results regarding impact of volcanic eruptions on climate change in Earth's history. Present global warming has been attributed to anthropogenic emissions of greenhouse gases, mainly carbon dioxide, however changes in global temperatures have occurred before the onset of anthropogenic emissions. Certain prehistoric climate changes are thought to be caused by emissions of volcanic gases to the atmosphere. Many studies have investigated the connection between volcanic events and subsequent changes in global temperatures. A majority have concluded that volcanic sulfur dioxide is the main direct and indirect climate forcing gas influencing temperatures over time. Increased volcanic activity over the last 15 years is thought to be an inhibiting factor on present global warming. This is supported by evidence of past volcanic events preceding global cooling and warming periods during Holocene and prehistoric times. Further, there are indications that factors such as geographical position, season, gas composition, magnitude and duration of an eruption influences the extent of the climate forcing.Records of climate such as ice cores and tree growth rings and isotopic characterization have made it possible to identify volcano eruptions over time and determine the identity of the erupting volcano. Past and present data from these can be used to gain a better understanding of past climate changes as well as making predictions about future changes as a result volcanic eruptions. However, accuracy regarding temporal and spatial resolution of these records is of great importance for the validity of the results.
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Colon, i. Bosch Mireia. "Analytical strategies based on inductively coupled plasma sprectroscopy (ICP) and diffusive gradients in thin fims (DGT) techniques for the assessment of environmental pollution indicators." Doctoral thesis, Universitat de Girona, 2011. http://hdl.handle.net/10803/84050.
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In this thesis, simple methods to determine sulfide at low levels (µg L-1) in aqueous samples and sediments by water free hydrogen sulfide vapor generation using a commercially available vapor generation accessory have been developed. The hydrogen sulfide is then introduced in the ICP-QMS, equipped with an octopole collision/reaction cell which is vented with hydrogen and helium gases, or in the ICP-AES where the optical path between the plasma and the monochromator is purged with nitrogen. Moreover some studies have been conducted for the determination of arsenic by ICP-MS in natural waters with high sodium and chloride content. Spectral and non spectral interferences on arsenic measurement have been investigated and different experiments have been developed to solve such interferences (optimizations of the cell collision conditions, arithmetic corrections, introduction of small amounts of alcohol). Finally, the use of the DGT technique (diffusive gradients in thin films) has been evaluated in acidic samples and mining wastes for the firs time.En aquesta tesi, s’han desenvolupat mètodes senzills per a la determinació de sulfur a baixes concentracions (µg L-1) en mostres aquoses i sediments mitjançant la generació de sulfur d’hidrogen, utilitzant un accessori de generació d’hidrurs comercial. Un cop format el sulfur d’hidrogen, aquest es pot introduir a l’ICP-QMS, equipat amb una cel•la de col•lisió/reacció o a l’ICP-AES amb el pas entre el plasma i el monocromador purgat amb nitrogen. També s’han fet alguns estudis per determinar arsènic amb ICP-MS en aigües naturals amb alt contingut de sodi i clor. S’han estudiat les interferències espectrals i no espectrals sobre aquest element i s’han dut a terme diferents experiments per a resoldre-les (optimització de la cel•la de col•lisió, aplicació de correccions matemàtiques, introducció de petites quantitats d’alcohol). Finalment, s’ha avaluat l’ús de la tècnica de DGT (diffusive gradients in thin films) en mostres àcides (pHs de 5 a 10) i residus de mineria per primera vegada.
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Santos, Luiz Felipe de Melo. "Efeito de doses, fontes e granulometria de enxofre na produção e estado nutricional dos capins mombaça e piatã." Dracena, 2018. http://hdl.handle.net/11449/180570.
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Orientador: Reges HeinrichsResumo: O enxofre é, provavelmente, o macronutriente menos empregado nas adubações, o que resulta na redução de rendimento e qualidade de forragem. Entre os nutrientes, apresenta um importante papel por participar em várias funções biológicas, faz parte da composição dos aminoácidos cisteína, metionina e cistina, acetil-CoA, bem como de enzimas que participam da fotossíntese e o metabolismo do nitrogênio. O objetivo foi avaliar a produção e estado nutricional dos capins Piatã e Mombaça em resposta a aplicação de doses e fontes de sulfato e enxofre elementar em Argissolo Vermelho Amarelo. Em virtude disso, realizou-se dois experimentos em casa de vegetação na Faculdade de Ciências Agrárias e Tecnológicas, UNESP, Campus de Dracena – SP, o primeiro foi no período de janeiro a março de 2017 e o segundo de outubro a janeiro de 2018, com o capim Piatã e de Mombaça, respectivamente. O delineamento experimental foi em blocos casualizados com quatro repetições, arranjados em esquema fatorial, 4x5, com quatro fontes de enxofre (Gipsita, Fosfogesso, S elementar em pó e S elementar pastilhado) e cinco doses de enxofre (0, 50, 100, 150 e 200 mg kg-1).Foram determinados os parâmetros biométricos como número de perfilhamento, massa seca da parte aérea (MSPA) e massa seca de raízes (MSR). O estado nutricional das plantas foi avaliado por meio da leitura SPAD e análise de macronutrientes N, P, K, Ca, Mg, S na parte aérea das plantas. Avaliou-se também o enxofre residual do solo e o pH do solo. Os res... (Resumo completo, clicar acesso eletrônico abaixo)
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Kosak, Rukan. "The Effects Of Promoters On The Sulfur Resistance Of Nox Storage/reduction Catalysts: A Density Functional Theory Investigation." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613442/index.pdf.
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High fossil fuel consumption in transportation and industry results in an increase of the emission of green-house gases. To preserve clean air, new strategies are required. The main intention is to decrease the amount of CO2 emission by using lean-burn engines while increasing the combustion efficiency and decreasing the fuel consumption. However, the lean-burn engines have high air-to-fuel ratio which complicates the reduction of the oxides of nitrogen, NOx . The emission of these highly noxious pollutants, NOx , breeds both environmental and health problems. Thus, new catalytic strategies have been steadily developed. One of these strategies is the NOx storage and reduction (NSR) catalysts. Since the reduction of the NOx under excess oxygen condition is very difficult, the NSR catalysts store the NOx until the end of the lean phase that is subsequently alternated with the rich-fuel phase during which the trapped NOx is released and reduced.
To develop NSR technology, different storage materials, the coverage of these metals/metal-oxides, support materials, precious metals, temperature, etc. have been widely investigated. In this thesis, the (100) surface of BaO with dopants (K, Na, Ca and La), (100) and (110) surfaces of Li2O, Na2O and K2O are investigated as storage materials. In addition, alkali metal (Li, Na and K) loaded (001) surface of TiO2 (titania) anatase is investigated as a support material for the NOx storage and reduction catalysts. The main aim is to increase the sulfur resistance.
The introduction of the dopants on the BaO (100) surface has increased the stability of the NO2 . The combination of local lattice strain and different oxidation state, which is obtained by the La doped BaO (100) surface, benefit both NO2 adsorption performance and sulfur tolerance. The binding energies of NO2 adsorption configurations over the alkali metal oxide (100) and (110) surfaces were higher than the binding energies of SO2 adsorption configurations. The stability of all of NO2 adsorption geometries on the alkali metal-loaded TiO2 (001) surface were higher than the stability of SO2 adsorption geometries. Increasing basicity enhanced the adsorption of NO2 molecule.
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Andrade, Daniel Junior de [UNESP]. "Viabilidade técnico-econômica da associação poda e controle químico no manejo da leprose dos citros." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/102277.
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andrade_dj_dr_jabo.pdf: 855007 bytes, checksum: 3075b77cbb230dea543d70a9287b1789 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O objetivo do trabalho foi avaliar a viabilidade técnico-econômica da poda associada ao controle químico no manejo da leprose. Visou também, investigar as relações entre leprose e características da planta, bem como o efeito de sucessivas aplicações de calda sulfocálcica sobre propriedades químicas do solo. O experimento foi conduzido de 2003 a 2010, totalizando sete safras, em um pomar de laranja „Pera‟ localizado no município de Reginópolis-SP. Neste pomar foram realizadas podas severas e leves, e replantio, e aplicações de acaricidas para controlar do ácaro vetor Brevipalpus phoenicis. Realizaram-se levantamentos populacionais do B. phoenicis e de ácaros predadores, quantificação da produção, incidência e severidade da leprose, assim como a viabilidade de cada estratégia empregada foi calculada. Nas duas últimas safras do experimento realizaram-se avaliações das características físico-químicas dos frutos, análises foliares e de solo. Após as sete safras, verificou-se que a poda utilizada isoladamente não foi suficiente para o controle da leprose, sendo necessária a associação de outras táticas. A poda leve associada a acaricidas específicos foi à tática mais eficiente e viável economicamente. Os parâmetros físico-químicos de frutos não foram afetados pela alta severidade leprose na planta, indicando que os frutos que permanecem na planta até a colheita apresentam características idênticas às plantas isentas de leprose. Entretanto, embora a leprose não afete a qualidade do suco, afeta significativamente a produtividade da planta, podendo reduzi-lá a zero. As plantas com maior severidade da leprose apresentaram menores teores foliares de cálcio e maiores teores de potássio, fósforo e nitrogênio. As várias aplicações de calda sulfocálcica sobre as plantas proporcionaram maior teor de enxofre no solo nas camadas de 0-20 cm e de 20-40 cm
The aim of this work was to evaluate the technical and economic feasibility of pruning associated with chemical control in citrus leprosis management. And also investigate the relationship among the disease and properties plant, as well as the effect of successive applications of lime sulfur on chemical properties of soil. The study was conducted from 2003 to 2010, totaling seven seasons in an orange plantation of the „Pear‟ variety in the city of Reginópolis-SP. In the orchard were realized severe and light pruning over citrus trees and replanting and pesticide spraying to control Brevipalpus phoenicismite, the disease vector. There had been performed B. phoenicis and predator mite population surveys, yield evaluation, leprosis incidence, as well as the variability of each strategy was also measured. By the two last seasons during the experiment was carried out fruit physical and chemical properties evaluation, leaf and soil analysis. After seven seasons period, it was observed that the pruning only is not able to control leprosis by itself, being necessary another strategy associated. The light pruning associated to the specific acaricide application was the more efficient and economically viable. The main fruit physical and chemical parameters were not affected by the leprosis incidence, what shows that the fruit that remain on the plant until the harvest have identical characteristics to that plant free from the disease. However, although the leprosis not affect juice quality, the disease reduces production significantly. The plant presenting higher leprosis severity present lower leaf calcium content and higher potassium, phosphorus and nitrogen contents.The various lime sulfur spray on the plant had provided a highersulfur content at 0 - 20 cm and 20 - 40 cm soil depth
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Cousins, Morgan. "I. Designing Brighter Fluorophores: A Computational And Spectroscopic Approach To Predicting Photophysical Properties Of Hydrazone-Based Dyes Ii. Developing Spectroscopic Methods To Better Understand The Cofactors Of Metalloproteins." ScholarWorks @ UVM, 2017. https://scholarworks.uvm.edu/graddis/787.
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Luminogens are molecules that emit light upon exposure to high-energy light, and fluorophores are one class of luminogens. Applications of fluorophores range from microviscosity sensors to light emitting diodes (LEDs), as well as biosensors, just to name a few. Many of these applications require the fluorophore to be in the aggregate or solid state. Some fluorophores become highly emissive in the aggregate state; these fluorophores are aggregation-induced emission (AIE) luminogens. Currently, very few quantum mechanical mechanisms have been proposed to describe the unique AIE behavior of luminogens.
Boron difluorohydrazone (BODIHY) dyes are a new type of AIE fluorophore. The bright emission is from the S>1 excited state (“anomalous” emission) contrary to Kasha’s Rule. Thus, the mechanism Suppression of Kasha’s Rule (SOKR) was proposed to be responsible for the family of BODIHY dyes. We hypothesize that the SOKR mechanism can explain AIE as well as the anomalous emission of other fluorophores. New BODIHY derivatives (para-CO2H BODIHY, aluminum difluorohydrazone (ALDIHY), and paranitro ALDIHY) were predicted to be bright anomalous fluorophores through density functional theory (DFT) and time-dependent DFT (TDDFT) investigations. In addition, a series of anomalous fluorophores were investigated to determine if their photophysical properties could be explained by the SOKR mechanism (azulene, 1,6-diphenyl-1,3,5hexatriene, and zinc tetraphenylporphyrin). Finally, several triazolopyridinium and triazoloquinolinium dyes were computationally investigated by DFT and TDDFT calculations, and an accurate computational model for the large Stokes shifts of these dyes was developed. In conclusion, a better understanding of the photophysical properties through DFT and TDDFT modeling and spectroscopic investigation of hydrazone-based fluorophores has been achieved.
In addition, the metal active sites and cofactors of metalloproteins were probed by optical spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and DFT modeling. In conjunction, these techniques can be used to elucidate the electronic structure responsible for the unique function of these metalloproteins. Specifically, a novel ironsulfur cluster of a metalloprotein that may be involved in endospore formation of Clostridium difficile, CotA, was characterized by magnetic circular dichroism (MCD) spectroscopy. We propose that CotA contains a high-spin [4Fe-4S] cluster and a Rieske [2Fe-2S] cluster. It appears that the multimerization of the protein is related to the cluster conversion at the interface of monomeric subunits where two [2Fe-2S] clusters combine to form the [4Fe-4S] cluster. In addition, a putative cobalamin acquisition protein from Phaeodactylum tricornutum, CBA1, was not expressed at sufficient concentrations in Escherichia coli for spectroscopic investigation. Finally, a new technique was developed using cobalt-59 NMR spectroscopy to better understand the nucleophilic character of cobalt tetrapyrroles, such as cobalamin (vitamin B12), as biological cofactors as well as synthetic catalysts. New insight into the electronic structure provides valuable information related to the mechanism of these metalloproteins.
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Naveau, Aude. "Etude et modélisation de la sorption d'ions à la surface de sulfures métalliques en conditions de stockage en milieu géologique profond." Reims, 2005. http://theses.univ-reims.fr/exl-doc/GED00000168.pdf.
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Le principe du stockage en milieu géologique profond est de confiner les colis de déchets par un ensemble de barrières ouvragée et géologique. Les eaux souterraines constituent l'un des principaux points faibles de la sûreté d'un stockage en contribuant à l'altération des barrières et à la migration des radionucléides à travers la géosphère. Ainsi, la compréhension des processus susceptibles de retarder cette migration est fondamentale pour évaluer la sûreté d'un stockage. Le but de nos travaux est d'étudier les processus de sorption entre des phases de sulfures métalliques, présentes sous forme d'inclusions dans la barrière géologique, et deux produits de fission à vie longue, l'iode et le sélénium. Après validation des protocoles mis en place pour limiter la dégradation par oxydation des solides étudiés (pyrite FeS2 et chalcopyrite CuFeS2), nous nous sommes attachés à décrire leur réactivité en milieu aqueux et en présence d'iode ou de sélénium. Les études potentiométriques montré que la réactivité de surface des sulfures métalliques étudiés était très faible en raison d'une surface spécifique très basse. Les études expérimentales de sorption ont montré d'une part l'absence d'affinité entre les iodures et les surfaces de sulfures métalliques et d'autre part une sorption significative de sélénium à la surface des différents solides. Les études spectroscopiques (XPS et SAX) ont permis de montrer que le sélénium était présent sous forme réduite au degré d'oxydation (-II) à la surface des sulfures métalliques. Le comportement du sélénium a finalement été décrit à l'aide de la théorie de complexation de surface avec le modèle de la double coucheThe storage of high-level nuclear wastes in a geological disposal is based on the concept of confinement by a multibarrier system. Transport by groundwaters is the most likely means for radionuclides to migrate through the engineered and geological barriers. Understanding processes which could delay this migration is therefore fundamental to ensure the timelessness of a deep geological repository. The present study was initiated to investigate sorption processes between sulfides minerals, present as inclusions in temperate soils, and two long-life fission products, iodine and selenium. All experiments were performed in strict anoxic conditions in order to prevent the studied solids (pyrite FeS2 and chalcopyrite CuFeS2) from oxidation. Potentiometric studies showed a weak reactivity of the metallic sulfides surfaces attributed to a low specific surface. Sorption experiments showed no affinity between iodide and metallic sulfides surfaces whereas selenium was well retained by the differents solids. Spectroscopic studies (XPS and XANES) showed a reduction of SeIV to Se-II on the sulfide surfaces. Selenium behaviour was finally described with the diffuse layer model using the surface complexation theory
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Naveau, Aude Dumonceau Jacques. "Etude et modélisation de la sorption d'ions à la surface de sulfures métalliques en conditions de stockage en milieu géologique profond." Reims : S.C.D de l'Université, 2005. http://scdurca.univ-reims.fr/exl-doc/GED00000168.pdf.
Full textBooks on the topic "Sulfur Dot"
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Weaver, R. D. Proceedings: DOE/EPRI Beta (Sodium/Sulfur) Battery Workshop VIII. Electric Power Research Institute, 1990.
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U.S. Coal Reserves: An Update By Heat And Sulfur Content... Errata, DOE/EIA-0529(92)... U.S. Department Of Energy. [S.l: s.n., 1998.
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Sulear a justiça restaurativa parte dois. Texto e contexto, 2021. http://dx.doi.org/10.54176/iorg3445.
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Sulear a justiça restaurativa as contribuiçoes latino americanas para a construção do movimento restaurativo. Texto e contexto editora, 2020. http://dx.doi.org/10.54176/xegf5932.
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O livro foi dividido por capítulos escritos por homens e mulheres latino-americanas que trabalham junto à justiça restaurativa em seus contextos próprios, convidados e convidadas a escrever em uma linguagem acessível e em primeira pessoa, contando sobre o que pensam a partir do chão onde pisam, democratizando o acesso às informações compartilhadas neste livro.
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Jovic, Sebastián Miguel. Geología y metalogénesis de las mineralizaciones polimetálicas del área El Tranquilo (Cerro León), sector central del Macizo del Deseado, provincia de Santa Cruz. Editorial de la Universidad Nacional de La Plata (EDULP), 2010. http://dx.doi.org/10.35537/10915/4346.
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La presente investigación tiene como eje principal el estudio detallado de las mineralizaciones y la geología de un área del Macizo del Deseado con características geológicas y metalogénicas únicas. La elección del área del El Tranquilo o también conocido como “anticlinal” El Tranquilo, como zona de estudio, se ha basado en el reducido conocimiento y la presencia características atípicas en las mineralizaciones y la escasa representación, en el Macizo del Deseado, de las rocas y unidades geológicas aflorantes. La investigación ha sido realizada en tres etapas: una primera con recopilación de antecedentes y trabajo de campo, una segunda analítica con trabajos de laboratorio y una tercera etapa interpretativa. Se realizó el procesado de imágenes satelitales (TM, SPOT, IKONOS) y se ejecutaron mapeos geológico-estructurales de detalle y semidetalle (con elaboración de una cartografía digital), descripción de testigos de sondeos (gran parte de los 30.000 metros de las perforaciones ejecutadas en la propiedad minera), se realizaron estudios petrográficos, calcográficos, de rayos X, determinaciones geoquímicas, estudios de inclusiones fluidas, de microscopía electrónica, microsonda electrónica, determinaciones geocronológicas y análisis de isótopos estables e inestables. Además se participó de otros trabajos complementarios realizados durante las distintas etapas de exploración minera, tales como geoquímica de suelos, muestras de trincheras y relevamientos magnetométricos y geoeléctricos terrestres y la interpretación, para la zona de trabajo, de estudios previos de magnetometría aérea y líneas sísmicas. El área del “anticlinal” El Tranquilo, está caracterizada por la presencia de rocas y unidades geológicas con escasa representación en el Macizo del Deseado, y representa una “ventana geológica” que permite el estudio del intervalo Triásico superior - Jurásico inferior, períodos que se encuentran poco expuestos en esta provincia geológica. La secuencia estratigráfica de este sector se inicia con las sedimentitas continentales, areniscas a areniscas conglomerádicas con intercalaciones de pelitas, del Grupo El Tranquilo, del Triásico medio a superior (Jalfin y Herbst 1995). Por encima, se presentan las rocas volcaniclásticas de la Formación Roca Blanca (Herbst, 1965), del Jurásico inferior. Esta es la litología más desarrollada en el área y está compuesta por tufitas, areniscas y sabulitas ricas en componentes volcánicos. Intruyendo a las sedimentitas continentales y a las tufitas, se disponen rocas básicas a intermedias del Jurásico inferior, que se presentan como filones capa de diabasa en el sector este del área y como pórfidos andesíticos de formas subcirculares en el sector noroeste, de la Formación Cerro León (Panza, 1995 y de Barrio et al., 1999). En los sectores norte y noreste del área afloran volcánitas del Jurásico medio a superior, basaltos y andesitas de la Formación Bajo Pobre, y en el sector sudoriental pequeños asomos de ignimbritas riolíticas del Grupo Bahía Laura (Panza, 1995). Estas unidades se encuentran parcialmente cubiertas por el Basalto Las Mercedes del Cretácico superior y el Basalto Cerro del Doce correspondiente al Eoceno (Panza, 1982) y finalizan esta secuencia sedimentos modernos, aluviales, coluviales y de bajos. En la presente investigación se determinó la presencia de niveles ignimbríticos ácidos y coladas basálticas intercaladas en las tufitas de la Formación Roca Blanca. A partir de las edades obtenidas, relaciones estratigráficas y composición se desvincula a los intrusivos dioríticos de la Formación Cerro León y se los asocia con el magmátismo de la Formación La Leona (Jurásico inferior). Los basaltos aflorantes en el área presentan características de basaltos continentales que se corresponden a los primeros indicios del magmatismo sinextensional jurásico y representan magmas básicos de origen mantélico que alcanzaron la superficie. Se los desvinculan de la Formación Bajo Pobre por ser ligeramente más antiguos al estar intercalados entre las tufitas de la Formación Roca Blanca (Jurásico inferior) y por presentar diferentes características isotópicas y petrogenéticas. Se define así una nueva unidad formacional para estas rocas denominándolas Formación El Piche. Los pórfidos andesíticos de la Formación Cerro León y las andesitas de la Formación Bajo Pobre presentan similitudes geoquímicas, isotópicas, petrogenéticas y edades semejantes, por lo que se interpreta un mismo origen para estas rocas, siendo los pórfidos andesíticos partes de los conductos de emisión de las coladas andesíticas. A diferencia del resto del Macizo del Deseado donde predomina casi por completo deformación con comportamiento netamente frágil, en el área de estudio se reconoció deformación tanto dúctil como frágil en las secuencias triásicas y jurásicas. Los rasgos estructurales más sobresalientes son: un domamiento regional de entre 15 a 20 km de diámetro, definido por Di Persia (1956) como “anticlinal” El Tranquilo, domamientos y plegamientos con dimensiones menores a 1 km localizados dentro de la antiforma regional, un sistema de fracturas radiales asociado al domamiento y la falla El Tranquilo con un sistema de vetas controladas por fallas. Se determinó que el “anticlinal” El Tranquilo, se formó por el emplazamiento de un cuerpo intrusivo no aflorante del orden de 8 a 10 Km de diámetro y profundidad mínima hasta su techo de 1400 m, subyaciendo al Grupo El Tranquilo y a la Formación Roca Blanca, y generando por su intrusión, el domamiento regional y los domamientos y plegamientos con dimensiones menores a 1 km localizados corresponde a una deformación producida por lacolitos o stocks no aflorantes. En el área de estudio se reconocieron gran cantidad de mineralizaciones, las que totalizan ~80 km lineales de vetas, ubicadas principalmente en el sector central del área. Las vetas se concentran hacia el este de la estructura regional, la falla El Tranquilo, son subparalelas a esta estructura y están emplazadas en las tufitas de la Formación Roca Blanca y pelitas y areniscas del Grupo El Tranquilo. Se han discriminado dos tipos distintos de vetas según su composición y expresión superficial, vetas formadas por importantes zonas de oxidación que representan la expresión superficial de vetas de sulfuros, y vetas, brechas hidrotermales, vetillas y stockworks formados principalmente por cuarzo. A partir de las distintas características observadas y datos obtenidos (composición, signatura geoquímica, mineralogía, datos de inclusiones fluidas, isótopos, controles estructurales y litológicos y edades) se ha podido diferenciar dos estilos de mineralización. La mineralización polimetálica que presenta una compleja mineralogía de sulfuros asociada a una signatura geoquímica de In, Cu, Au, As, Sn, W, Bi, Zn, Pb, Ag, Cd y Sb. Las temperaturas y salinidades de los fluidos indican un sistema epitermal para la formación de estas vetas. Su génesis esta vinculada a los cuerpos intrusivos dioríticos reducidos por sedimentos ricos en materia orgánica, concentrando en los fluidos hidrotermales In, Sn, Ag, W, Bi. Se define a esta mineralización como un depósito epitermal vetiforme polimetálico rico en In semejante a los depósitos de Japón y Bolivia. Las características de esta mineralización y la edad Jurásica inferior (193 Ma) confirman la presencia de un nuevo tipo de deposito epitermal que difiere del clásico modelo de baja sulfuración del Macizo del Deseado y que no se encuentra asociado al importante volcanismo bimodal del Jurásico medio a superior (Complejo Bahía Laura), como la mayoría de las mineralizaciones del Macizo del Deseado. Este hecho potencia el hallazgo de otros tipos de depósitos epitermales polimetálicos, asociados a otras rocas y con diferentes asociaciones metalogénicas. La mineralización argentífera está formada por cuarzo, carbonatos y en menor medida sulfuros y sulfosales con una signatura geoquímica de Ag (Au), Pb, Cu y Zn. Las temperaturas y salinidades de los fluidos indican un sistema epitermal para la formación de estas vetas. Su génesis está vinculada al magmatismo intermedio de las Formaciones Cerro León y Bajo Pobre, atribuyéndole una edad Jurásica media (168 Ma). Según sus características esta mineralización puede ser definida como un depósito epitermal de sulfuración intermedia. Esta mineralización también representa una variación en el modelo de baja sulfuración del Macizo del Deseado, pero está genéticamente asociada al volcanismo bimodal del Complejo Bahía Laura (Fm. Bajo Pobre) por lo que podría incluirse dentro de las mineralizaciones de la Provincia auroargéntifera del Deseado.
Book chapters on the topic "Sulfur Dot"
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Klokishner, S. I., and O. S. Reu. "Spin Crossover in Iron(II) Complexes with Mixed Nitrogen-Sulfur Coordination: DFT Modeling." In IFMBE Proceedings, 33–36. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-31866-6_7.
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Williams, Neil. "Light-Element Stable Isotope Studies of the Clastic-Dominated Lead–Zinc Mineral Systems of Northern Australia and the North American Cordillera: Implications for Ore Genesis and Exploration." In Isotopes in Economic Geology, Metallogenesis and Exploration, 329–72. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-27897-6_11.
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AbstractClastic-dominated lead–zinc (CD Pb–Zn) deposits are an important source of the world’s Pb and Zn supply. Their genesis is contentious due to uncertainties regarding the time of ore formation relative to the deposition of the fine-grained carbonaceous strata that host CD Pb–Zn mineralization. Sulfur-isotopic studies are playing an important role in determining if ore minerals precipitated when hydrothermal fluids exhaled into the water column from which the host strata were being deposited, or when hydrothermal fluids entered the host strata during diagenesis or even later after lithification. Older conventional S-isotopic studies, based on analyses of bulk mineral-separate samples obtained by either physical or chemical separation methods, provided data that has been widely used to support a syngenetic-exhalative origin for CD Pb–Zn mineralization. However, with the advent in the late 1980’s of in situ S-isotopic studies using micro-analytical methods, it soon became apparent that detailed S-isotopic variations of genetic importance are blurred in conventional analytical data sets because of averaging during sample preparation. Clastic-dominated Pb–Zn mineralization in the North Australian Proterozoic metallogenic province and the North American Paleozoic Cordilleran province has been the subject of many stable isotope studies based on both bulk and in situ analytical methods. Together with detailed mineral texture observations, the studies have revealed a similar sulfide mineral paragenesis in both provinces. The earliest sulfide phase in the paragenesis is fine-grained pyrite that sometimes has a framboidal texture. This pyrite typically has a wide range of δ34S values that are more than 15‰ lower than the value of coeval seawater sulfate. These features are typical of, and very strong evidence for, pyrite formation by bacterial sulfate reduction (BSR) either syngenetically in an anoxic water column or during early diagenesis in anoxic muds. The formation of this early pyrite is followed by one or more later generations of pyrite that often occur as overgrowths around the early pyrite generation. The later pyrite generations have δ34S values that are much higher than the early pyrite, often approaching the value of coeval seawater sulfate. Later pyrite formation has been variously attributed to BSR in a more restricted diagenetic environment, to sulfate driven-anaerobic oxidation of methane (SD-AOM) and to abiotic thermal sulfate reduction (TSR), with all three mechanisms again involving coeval seawater sulfate. The main sulfide ore minerals, galena and sphalerite, either overlap with or postdate later pyrite generations and are most often attributed to TSR of seawater sulfate. However, in comparison with pyrite, there is a dearth of in situ δ34S data for galena and sphalerite that needs to be rectified to better understand ore forming processes. Importantly, the available data do not support a simple sedimentary-exhalative model for the formation of all but part of one of the Northern American and Australian deposits. The exception is the giant Red Dog deposit group in Alaska where various lines of evidence, including stable isotopic data, indicate that ore formation was protracted, ranging from early syn-sedimentary to early diagenetic sulfide formation through to late sulfide deposition in veins and breccias. The Red Dog deposits are the only example with early sphalerite with extremely low negative δ34S values typical of a BSR-driven precipitation mechanism. By contrast, later stages of pyrite, sphalerite and galena have higher positive δ34S values indicative of a TSR-driven precipitation mechanism. In CD Pb–Zn deposits in carbonate-bearing strata, carbon and oxygen isotope studies of the carbonates provide evidence that the dominant carbonate species in the ore-forming hydrothermal fluids was H2CO3, and that the fluids were initially warm (≥ 150 °C) and neutral to acid. The δ18O values of the hydrothermal fluids are ≥ 6‰, suggesting these fluids were basinal fluids that evolved through exchange with the basinal sedimentary rocks. Known CD Pb–Zn deposits all occur at or near current land surfaces and their discovery involved traditional prospecting, geophysical and geochemical exploration techniques. Light stable isotopes are unlikely to play a significant role in the future search for new CD Pb–Zn deposits deep beneath current land surfaces, but are likely to prove useful in identifying ore-forming hydrothermal fluid pathways in buried CD Pb–Zn systems and be a vector to new mineralization.
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Culver, David C., and Tanja Pipan. "Ecosystem Function." In The Biology of Caves and Other Subterranean Habitats, 80–97. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198820765.003.0004.
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An important aspect of all aquatic subterranean ecosystems is the nature and connectivity of surface inputs. A theme common to both is heterogeneity of inputs that exist at even the smallest scale. At least in cave streams, carbon appears to be limiting. Studies at the scale of entire caves are of two very different kinds. For caves with surface inputs, inputs from percolation water are quantitatively less important than inputs from sinking streams, but are qualitatively more important because they occur throughout the cave and form the basis for the biofilm. Sulfur-oxidizing bacteria are the trophic base for most chemoautotrophic cave communities. Only two ecosystem studies of an entire karst basin have been carried out. For the Dorvan basin in France, most carbon entering the ecosystem is DOC, and there is considerable storage of organic carbon in sediments. In the Edwards Aquifer of Texas, chemolithoautotrophy contributes to all the components.
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Day, S., G. A. Coulter, and M. Falutsu. "Geochemical studies to characterize the complex sulfur mineralogy at Red Dog Pb-Zn Mine." In Mine Planning and Equipment Selection 2000, 891–98. Routledge, 2018. http://dx.doi.org/10.1201/9780203747124-167.
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Kumar Bal, Dharmendra, and Jaykumar B. Bhasarkar. "Sono-Bio-Desulphurization of Liquid Fuel using Free and Immobilized Cell." In Ultrasound Technology for Fuel Processing, 253–79. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815049848123010016.
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In view of environmental concerns, the production of clean energy is one of the most critical issues in modern years to accommodate the growing energy needs of society (domestic usage), agriculture, and industry. Clean energy can be accomplished in several ways. A possible solution to this issue is to use renewable energy sources such as solar, wind, and nuclear power universally. The use of conventional techniques to produce energy by the combustion of fossil fuels has adverse effects on the environment due to the emission of greenhouse gas that contributes to global warming. The conventional method adopted by petroleum refinery industries has not been successful for profound desulphurization to achieve low sulphur contents. To overcome this, several new alternative chemicals, and physical and biological techniques have been developed to meet ultra-low sulphur fuel in the last two decades. Microbial desulphurization is one of the emerging alternative techniques that can remove the organo-sulphur compounds from fuels. The limitation of microbial desulphurization is the slow kinetics and it can be overcome by combining it with other desulphurization processes (hybrid system), such as the ultrasound-assisted processes. This chapter presents a critical account of research in different facets of ultrasound-assisted biodesulphurization. The microbial desulphurization process involves the use of free or immobilized microorganisms over the PU foams and the application of enzymes for desulphurization of DBT. The enzymes or proteins can act as catalysts to degrade sulphur compounds present in fuels. The present chapter also deals with the ultrasound-assisted microbial and enzymatic pathways. The concurrent analysis of experimental results on enzymatic biodesulphurizarion along with simulation results of cavitation bubble dynamics provides more insight into the actual mechanism of ultrasound on microbial and enzymatic desulphurization process.
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Ouchenane, Sihem, Ramzy Jalgham, Sarra Rezgoune, and Gourisankar Roymahapatra. "Electrochemical and Computational Study of Cysteine as a Green Corrosion Inhibitor of Mild Steel in Sulfuric Acid Medium." In Handbook of Research on Corrosion Sciences and Engineering, 405–32. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-7689-5.ch015.
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Amino acids are well known as an effective green corrosion inhibitor. In this study, the authors describe the corrosion inhibition of cysteine (Cys) on the mild steel in sulfuric acid using potentiodynamic polarization, electrochemical impedance spectroscopy. The results suggested that Cys can be used as effective corrosion inhibitors and act as mixed-type inhibitors. The inhibition efficiency reaches 70%. The electronic structure and the inhibition mechanism of Cys was studied using density functional theory (DFT) calculations and Monte Carlo simulation. Molecular adsorption on Fe2O3 surface (110) was investigated using Monte Carlo Simulation. All the steps of quantum calculations and Monte Carlo Simulation were explained in detail and therefore the researchers could follow this study in their future researches.
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Rahman, Shofiur, Paris E. Georghiou, and Abdullah Alodhayb. "Density functional theory (DFT) models for the desulfurization and extraction of sulfur compounds from fuel oils using ionic liquids." In Modelling of Chemical Process Systems, 53–90. Elsevier, 2023. http://dx.doi.org/10.1016/b978-0-12-823869-1.00011-9.
Full textConference papers on the topic "Sulfur Dot"
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Albaladejo-Siguan, Miguel, Anatol Prudnikau, Alina Senina, Elizabeth C. Baird, Yvonne J. Hofstetter, Julius Brunner, Yana Vaynzof, and Fabian Paulus. "Bis(stearoyl) Sulfide: A Stable, Odor-free Sulfur Precursor for High-Efficiency Metal Sulfide Quantum Dot Photovoltaics." In MATSUS23 & Sustainable Technology Forum València (STECH23). València: FUNDACIO DE LA COMUNITAT VALENCIANA SCITO, 2022. http://dx.doi.org/10.29363/nanoge.matsus.2023.046.
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Wong, Bunsen, Dennis Thomey, Lloyd Brown, Martin Roeb, Robert Buckingham, and Christian Sattler. "Sulfur Based Thermochemical Energy Storage for Concentrated Solar Power." In ASME 2013 7th International Conference on Energy Sustainability collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/es2013-18283.
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A sulfur based thermochemical energy storage cycle for baseload power generation is being developed under the support of US DOE Sunshot program. Solar heat is stored in elemental sulfur via thermal decomposition of sulfuric acid and disproportionation of sulfur dioxide into elemental sulfur and sulfuric acid. Heat energy is recovered upon sulfur combustion. On-sun decomposition of sulfuric acid in a solar furnace has been demonstrated between 650 and 850°C. Near equilibrium conversion was obtained at high temperature but conversion was reduced due to catalyst poisoning at the lower temperatures. Sulfur dioxide disproportionation modeling showed the reaction driving force is maximized at the high system pressure and low system temperature. The effect of system pressure was validated experimentally. However, the disproportionation rate was found to increase with system temperature as a result of increased reaction kinetics. Homogenous iodide catalysts were used to further enhance the degree of disproportionation and the reaction rate. The process steps required to recover the catalyst for reuse have been verified.
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Meyerson, Melissa, and Leo Small. "Mediated Lithium-Sulfur Flow Batteries." In Proposed for presentation at the DOE Office of Electricity Peer Review held October 26-28, 2021 in virtual,. US DOE, 2021. http://dx.doi.org/10.2172/1891595.
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Beall, Philip Wilkin, and Jerry Michael Neff. "Potential Nontraditional Uses of Byproduct E&P Produced Sulfur in Kazakhstan." In SPE/EPA/DOE Exploration and Production Environmental Conference. Society of Petroleum Engineers, 2005. http://dx.doi.org/10.2118/94177-ms.
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Werne, Josef, Molly O'Beirne, Morgan Raven, Bart van Dongen, Alice Bosco-Santos, and William Gilhooly Iii. "Structural Characteristics and Sulfur Isotope Compositions of Laboratory Sulfurized Carbohydrates and DOM." In Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.2848.
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Onawole, Abdulmujeeb T., Ibnelwaleed A. Hussein, Musa E. M. Ahmed, Mohammed A. Saad, and Santiago Aparicio. "DFT-MD Dissolution of Oilfield Pyrite Scale using Borax." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0017.
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Introduction: Oilfield scales including pyrite form in oil and gas pipelines, underground tubing, and surface equipment thus blocking the flow of fluids and hindering production. Hence, the need for the development of effective chemicals in scale dissolution and removal. Materials and methods: A computational technique known as Density Functional Theory- Molecular Dynamics (DFT-MD) was employed to investigate the use of borax in scale dissolution. This method aids the understanding at the atomic level of scale dissolution by using Quantum ATK’s virtual Nano lab and VASP for model building and DFT-MD calculations respectively. Geometrical studies and radial distribution functions were carried out for data analysis. Results: The results show that potassium ion preferentially bonds to the sulfur atoms in the top layer of the pyrite surface rather than with iron. Hence, becoming the predominant factor that is responsible for pyrite dissolution. The K-S bonds evolve dynamically and expose the rest of the pyrite surface. Conclusions/future directions: The presence of a chelating agent alongside borax would prevent Fe-S bond formation. Hence, it is proposed that borax, in conjunction with chelating agents, would be efficient in pyrite scale dissolution and removal. This technique can be used to study other iron sulfide scales such as troilite and greigite, which have different iron to sulfur ratio compared to pyrite. This will consequently help boost production in the upstream sector.
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Dive, Aniruddha, Ramiro Gonzalez, and Soumik Banerjee. "Graphene/Sulfur and Graphene Oxide/Sulfur Composite Cathodes for High Performance Li-S Batteries: A Molecular Dynamics Study." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-67590.
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Lithium – sulfur (Li-S) battery, with theoretical capacity (∼1675 mAh/g) and energy density comparable to that of gasoline, is a promising technology meeting the demands of next-generation electric vehicles. However, the Li-S battery hasn’t been able to reach the theoretically predicted capacity due to several limitations, which include low electrical conductivity of pure sulfur cathode and loss of active material due to dissolution of intermediate polysulfides from the cathode during repetitive charge – discharge cycling referred commonly as “polysulfide shuttle”. Graphene/Graphene oxide (GO) are being explored as cathodes/cathode supports for Li-S batteries to alleviate these problems. We have employed molecular dynamics simulations to calculate the density distributions of polysulfides (S82−) in dimethoxy ethane (DME) – 2, 4 – dioxalane (DOL) electrolyte (1:1 v/v) in the vicinity of different graphene and GO structures, in order to study the impact of hydroxyl functional groups in GO on anchoring polysulfides. Density distribution of polysulfides provides valuable insight on the role of functional groups in successful anchoring of polysulfides onto the GO cathode supports structures.
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Zarea, Mures, Stephane Hertz-Clemens, Remi Batisse, and Philippe Cardin. "Experimental Investigation on Combined “Dent and Gouge” Defects on Vintage Steel Transmission Pipelines." In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33538.
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Mechanical Damage on pipelines is the most frequent in service failure cause, at least in Europe. The category of Mechanical Damage actually covers on one hand rock dents, on the other hand, combined “Dent and Gouge” defects resulting from an impact by a ground moving machinery. The latter are complex defects in terms of geometry and mechanical behavior. Improved understanding of toughness reduction in these defects and their vicinity, especially in the case of vintage pipelines, and its impact on burst pressure and remaining fatigue lifetime is crucial in order to ensure a high safety level at the best economic conditions for transmission pipelines. PRCI and DOT/PHMSA supported a large experimental program to investigate the burst and fatigue strength of such defects in modern pipes as well as in vintage pipes by producing very detailed reference experimental data in order to support improvement of current burst and fatigue strength models for these defects. This paper focuses on experimental results data for two vintage pipes removed from service, one 26″ in diameter, X52 grade (from US) with high carbon content and sulfur content involving very low toughness and another 24″ in diameter, X63 grade (from Europe) characterized by alternated pearlite and ferrite bands. In each pipe, two different types of combined “Dent and Gouge” defects were created, “shallow dent with shallow gouge” and “severe dent with moderate gouge”. Each defect was reproduced three times: • One for destructive metallurgical investigation; • A second one for highly instrumented burst test; • A third one for highly instrumented fatigue test. The defect profile was monitored during pressure increase until burst, and a camera recorded pictures at each fatigue cycle to detect crack initiation at the gouge bottom and its further propagation. The different features of the experimental work and results described in this paper are: • Material characterization; • Metallurgical and residual stress investigation on combined dent and gouge defects; • Burst tests conditions and results; • Fatigue tests conditions and results. • Comparison with results from modern pipes containing the same types of defects. All this experimental data is made available for an in-depth understanding of the “Dent and Gouge” type defects leading to improved models, as well as reference data for validating these improved models for burst and fatigue strength of these defects.
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Osborne, Dustin T., Steven G. Fritz, Mike Iden, and Don Newburry. "Exhaust Emissions From a 2,850 kW EMD SD60M Locomotive Equipped With a Diesel Oxidation Catalyst." In ASME/IEEE 2007 Joint Rail Conference and Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/jrc/ice2007-40060.
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This paper describes the test results of a program to apply an experimental diesel oxidation catalyst (DOC) to a 2,850 kW freight locomotive. Locomotive emissions and fuel consumption measurements were performed on an Electro-Motive Diesel (EMD) model SD60M locomotive, owned by Union Pacific Railroad company, that had been recently rebuilt to EPA Tier 0 exhaust emission certification levels. Emission testing was performed at the Southwest Research Institute (SwRI) Locomotive Exhaust Emissions Test Center in San Antonio, Texas. US EPA-regulated emission levels of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and participate (PM) were measured using U.S. EPA locomotive certification test procedures in three configurations; first a baseline with a relatively high sulfur diesel fuel (2,913 ppm sulfur) meeting EPA locomotive certification test specifications, and another baseline using ultra-low sulfur diesel fuel (ULDS), and finally a test using ULSD after the installation of a diesel oxidation catalyst designed and manufactured by MIRATECH Corporation (patent pending). The DOC was applied pre-turbine, within the exhaust manifold due to both space and exhaust temperature considerations. This paper describes the design of the DOC-equipped exhaust manifold, and reports the changes in the regulated exhaust emission levels between the baseline tests and after installation of the DOC. Also described is a locomotive on-board monitoring system used to monitor DOC performance during ongoing revenue service field testing.
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Lahoda, Edward J., John E. Goossen, Regis A. Matzie, and Jason P. Mazzoccoli. "Optimization of the Westinghouse Sulfur Process for Hydrogen Generation and the Interface With an HTGR." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49031.
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The Westinghouse Sulfur Process is a member of the sulfur family of hydrogen generating thermochemical cycles being considered by the DOE for coupling with an HTGR. It has been proven experimentally and utilizes mature technology. Westinghouse has identified process improvements that increase the efficiency and reduce materials and HTGR-Hydrogen Process integration issues. Increasing the hydrogen plant operating pressure improves the thermal efficiency of the Westinghouse Sulfur Process from 40% to ∼55% (LHV basis) at H2SO4 concentrations of 40% to 80% by weight. The use of a directly heated decomposition reactor in conjunction with an HTGR allows higher decomposition reactor operating temperatures. This increases the per-pass percent conversion and increases overall efficiency. Other advantages are total separation of the coolant and process streams, the maturity of this technology (it has been used for over a century in the steel industry at temperatures up to 1,200°C), and the ready availability of materials.
Reports on the topic "Sulfur Dot"
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Sadasivakurup, Saisree, Sandhya Karunakaran Yesodha, and Arya Nair Jayadharan Salini. Graphene quantum dots doped with sulfur and nitrogen as versatile electrochemical sensors for heavy metal ions Cd(II), Pb(II), and Hg(II). Peeref, June 2023. http://dx.doi.org/10.54985/peeref.2306p9972799.
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Lacerda Silva, P., G. R. Chalmers, A. M. M. Bustin, and R. M. Bustin. Gas geochemistry and the origins of H2S in the Montney Formation. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329794.
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The geology of the Montney Formation and the geochemistry of its produced fluids, including nonhydrocarbon gases such as hydrogen sulfide were investigated for both Alberta and BC play areas. Key parameters for understanding a complex petroleum system like the Montney play include changes in thickness, depth of burial, mass balance calculations, timing and magnitudes of paleotemperature exposure, as well as kerogen concentration and types to determine the distribution of hydrocarbon composition, H2S concentrations and CO2 concentrations. Results show that there is first-, second- and third- order variations in the maturation patterns that impact the hydrocarbon composition. Isomer ratio calculations for butane and propane, in combination with excess methane estimation from produced fluids, are powerful tools to highlight effects of migration in the hydrocarbon distribution. The present-day distribution of hydrocarbons is a result of fluid mixing between hydrocarbons generated in-situ with shorter-chained hydrocarbons (i.e., methane) migrated from deeper, more mature areas proximal to the deformation front, along structural elements like the Fort St. John Graben, as well as through areas of lithology with higher permeability. The BC Montney play appears to have hydrocarbon composition that reflects a larger contribution from in-situ generation, while the Montney play in Alberta has a higher proportion of its hydrocarbon volumes from migrated hydrocarbons. Hydrogen sulphide is observed to be laterally discontinuous and found in discrete zones or pockets. The locations of higher concentrations of hydrogen sulphide do not align with the sulphate-rich facies of the Charlie Lake Formation but can be seen to underlie areas of higher sulphate ion concentrations in the formation water. There is some alignment between CO2 and H2S, particularly south of Dawson Creek; however, the cross-plot of CO2 and H2S illustrates some deviation away from any correlation and there must be other processes at play (i.e., decomposition of kerogen or carbonate dissolution). The sources of sulphur in the produced H2S were investigated through isotopic analyses coupled with scanning electron microscopy, energy dispersive spectroscopy, and mineralogy by X-ray diffraction. The Montney Formation in BC can contain small discrete amounts of sulphur in the form of anhydrite as shown by XRD and SEM-EDX results. Sulphur isotopic analyses indicate that the most likely source of sulphur is from Triassic rocks, in particular, the Charlie Lake Formation, due to its close proximity, its high concentration of anhydrite (18-42%), and the evidence that dissolved sulphate ions migrated within the groundwater in fractures and transported anhydrite into the Halfway Formation and into the Montney Formation. The isotopic signature shows the sulphur isotopic ratio of the anhydrite in the Montney Formation is in the same range as the sulphur within the H2S gas and is a lighter ratio than what is found in Devonian anhydrite and H2S gas. This integrated study contributes to a better understanding of the hydrocarbon system for enhancing the efficiency of and optimizing the planning of drilling and production operations. Operators in BC should include mapping of the Charlie Lake evaporites and structural elements, three-dimensional seismic and sulphate ion concentrations in the connate water, when planning wells, in order to reduce the risk of encountering unexpected souring.
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Demonstration of Selective Catalytic Reduction Technology to Control Nitrogen Oxide Emissions From High-Sulfur, Coal-Fired Boilers: A DOE Assessment. Office of Scientific and Technical Information (OSTI), December 1999. http://dx.doi.org/10.2172/14992.
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