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The development of a biocatalytic process for the conversion of acrylonitrile to ammonium acrylateWebster, Neil A. January 1996 (has links)
No description available.
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Interfacial (o/w) Properties of Naphthenic Acids and Metal Naphthenates, Naphthenic Acid Characterization and Metal Naphthenate InhibitionBrandal, Øystein January 2005 (has links)
<p>Deposition of metal naphthenates in process facilities is becoming a huge problem for petroleum companies producing highly acidic crudes. In this thesis, the main focus has been towards the oil-water (o/w) interfacial properties of naphthenic acids and their ability to react with different divalent cations across the interface to form metal naphthenates.</p><p>The pendant drop technique was utilized to determine dynamic interfacial tensions (IFT) between model oil containing naphthenic acid, synthetic as well as indigenous acid mixtures, and pH adjusted water upon addition of different divalent cations. Changes in IFT caused by the divalent cations were correlated to reaction mechanisms by considering two reaction steps with subsequent binding of acid monomers to the divalent cation. The results were discussed in light of degree of cation hydration and naphthenic acid conformation, which affect the interfacial conditions and thus the rate of formation of 2:1 complexes of acid and cations. Moreover, addition of non-ionic oil-soluble surfactants used as basis compounds in naphthenate inhibitors was found to hinder a completion of the reaction through interfacial dilution of the acid monomers.</p><p>Formation and stability of metal naphthenate films at o/w interfaces were studied by means of Langmuir technique with a trough designed for liquid-liquid systems. The effects of different naphthenic acids, divalent cations, and pH of the subphase were investigated. The results were correlated to acid structure, cation hydration, and degree of dissociation, which all affect the film stability against compression.</p><p>Naphthenic acids acquired from a metal naphthenate deposit were characterized by different spectroscopic techniques. The sample was found to consist of a narrow family of 4-protic naphthenic acids with molecular weights around 1230 g/mol. These acids were found to be very o/w interfacially active compared to normal crude acids, and to form Langmuir monolayers with stability depending on the aqueous pH. At high pH, addition of Ca<sup>2+</sup> increased the film stability due to formation of calcium naphthenate at the surface.</p><p>A new experimental setup based on near infrared spectroscopy was used to monitor the formation, growth, and inhibition of calcium naphthenate particles in o/w systems. This method was found to be suitable for studies of particle formation rate and growth qualitatively under different experimental conditions.</p>
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Interfacial (o/w) Properties of Naphthenic Acids and Metal Naphthenates, Naphthenic Acid Characterization and Metal Naphthenate InhibitionBrandal, Øystein January 2005 (has links)
Deposition of metal naphthenates in process facilities is becoming a huge problem for petroleum companies producing highly acidic crudes. In this thesis, the main focus has been towards the oil-water (o/w) interfacial properties of naphthenic acids and their ability to react with different divalent cations across the interface to form metal naphthenates. The pendant drop technique was utilized to determine dynamic interfacial tensions (IFT) between model oil containing naphthenic acid, synthetic as well as indigenous acid mixtures, and pH adjusted water upon addition of different divalent cations. Changes in IFT caused by the divalent cations were correlated to reaction mechanisms by considering two reaction steps with subsequent binding of acid monomers to the divalent cation. The results were discussed in light of degree of cation hydration and naphthenic acid conformation, which affect the interfacial conditions and thus the rate of formation of 2:1 complexes of acid and cations. Moreover, addition of non-ionic oil-soluble surfactants used as basis compounds in naphthenate inhibitors was found to hinder a completion of the reaction through interfacial dilution of the acid monomers. Formation and stability of metal naphthenate films at o/w interfaces were studied by means of Langmuir technique with a trough designed for liquid-liquid systems. The effects of different naphthenic acids, divalent cations, and pH of the subphase were investigated. The results were correlated to acid structure, cation hydration, and degree of dissociation, which all affect the film stability against compression. Naphthenic acids acquired from a metal naphthenate deposit were characterized by different spectroscopic techniques. The sample was found to consist of a narrow family of 4-protic naphthenic acids with molecular weights around 1230 g/mol. These acids were found to be very o/w interfacially active compared to normal crude acids, and to form Langmuir monolayers with stability depending on the aqueous pH. At high pH, addition of Ca2+ increased the film stability due to formation of calcium naphthenate at the surface. A new experimental setup based on near infrared spectroscopy was used to monitor the formation, growth, and inhibition of calcium naphthenate particles in o/w systems. This method was found to be suitable for studies of particle formation rate and growth qualitatively under different experimental conditions.
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The Association between Adult Self-reported Asthma & Potential Exposures to Asthma Triggers in Virginia Workplaces: An Ecological StudyBowman, Jeanette R. 01 January 2007 (has links)
Introduction: Work-related asthma (WRA) is thought to be the most common occupational lung disease in the U.S., but there is no standard case definition of WRA. Most states, including Virginia, do not require WRA diagnoses to be reported to health departments. At present, there is too little epidemiological data on WRA in Virginia to direct public health planning efforts. Objectives: The first objective of this study was to estimate potential exposure to workplace asthma triggers in each of Virginia's 35 health districts. The second objective was to examine associations at the health district level between workplace asthma triggers, other asthma risk factors, and asthma prevalence in Virginia. The third objective was to identify the specific health districts in which workers face the highest risk of WRA. Methods: This ecological study required merging three datasets. Information on weight, age, race/ethnicity, income, gender, and histories of asthma diagnosis and smoking was obtained from the Behavioral Risk Factor Surveillance System (BRFSS) and aggregated at the health district level. Information from the Virginia Employment Commission on the location, industry, and number of employees of each business in the state was combined with data on the asthma triggers found nationwide in specific industries to calculate estimates of potential exposure to WRA triggers in each health district. Descriptive, correlational and multiple regression analyses were conducted, and health districts were sorted by asthma prevalence, or number of workplace triggers, or trigger-based multivariate models of WRA risk.Results: On average, there are 50,104 employees potentially exposed to five or more asthma triggers in workplaces per health district. The number of ever-diagnosed adult asthmatics was highly correlated with the number of workplace asthma triggers in a health district, as well as with all demographic and behavioral risk factors. A linear regression model including number of workplace triggers, number of obese adults, and number of adults with incomes below 200% of poverty accounted for 84% of the variance in health district asthma prevalence. There was little overlap (2 health districts) between the set of highest-risk health districts identified by this model and the set identified by a sort on asthma prevalence alone. Conclusion: The findings of this exploratory ecological analysis suggest that the number of asthma cases in a health district may be an insufficient indicator of health district risk of WRA. Additional WRA surveillance and epidemiological research on WRA may be warranted in the health districts shown in this study to be at highest risk of the disease.
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Screening Evaluation of Risk Assessment Tools that Assist in Exposure Assessment and Prioritization of Hazards in a Chemical Manufacturing FacilityCundiff, Stephen J. January 2016 (has links)
No description available.
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Continuous multi-step synthesis by extrusion - telescoping solvent-free reactions for greater efficiencyCrawford, Deborah E., Miskimmin, C.K., Cahir, J., James, S.L. 13 February 2020 (has links)
Yes / Chemical manufacturing typically requires more than one step,
involving multiple batch processes, which makes synthesis at scale
laborious and wasteful. Herein, we demonstrate that several reactions can be telescoped into a single continuous process and/or be
carried out as a continuous multi-component reaction (MCR), by
twin screw extrusion (TSE), in the complete absence of solvent. / EPSRC (EP/L019655/1).
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MACT Implementation at an Organic Chemical Manufacturing Facility: Human Health Risk ReductionGordon, Keith 05 August 2010 (has links)
Human health risk assessments are used by environmental regulatory agencies to determine risk from Hazardous Air Pollutants (HAPs). In this study, the Human Exposure Model (HEM-3) was used to compare the cancer and non-cancer inhalation health effects of a single organic chemical manufacturing facility in Geismar, Louisiana prior to and after Maximum Achievable Control Technologies (MACT) were implemented. The results indicate significant reductions in both cancer risk and non-cancer hazards. The analysis also indicated that the equivalent cancer risk reduction could have been achieved by addressing MACT in only one production process and one single pollutant (ethylene dichloride) within that process. This demonstrates the value that these risk assessments have at evaluating emissions at the facility level, and how they could be used in the control strategy decision making process.
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The Encouragement of Technological Change for Preventing Chemical Accidents: Moving Firms from Secondary Prevention and Mitigation to Primary PreventionAshford, Nicholas January 1993 (has links)
Office of Chemical Emergency Preparedness and Prevention, U.S. Environmental Protection Agency, through a cooperative agreement
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Chemical Manufacturing in Developing Markets: Analysis and Cost EstimationsWasiu Peter Oladipupo (8669685) 28 July 2023 (has links)
<p>Developed countries have built wealth and prosperity on the strength of their manufacturing sectors, with China’s success story of lifting 800 million people out of extreme poverty in 30 years a sterling and most recent example of how manufacturing-led industrialization can foster economic development. Sub-Saharan Africa, unfortunately, find itself today in a similar situation as China did in 1990, with over 50% of the world’s desperately poor 719 million people living in the region. But unlike China, Sub-Saharan Africa is faced with the additional challenge of overcoming poverty in a world with stricter constraints to global trade and climate change limitations to modern-day industrialization. Compounding the challenges further is the region's limited know-how and human capital — a consequence of years of underdevelopment, creating a classic chicken and egg dilemma where the lack of industrialization perpetuates the dearth of know-how and human capital, and vice versa.</p><p>Considering these challenges, we investigate how chemical manufacturing and what chemical manufacturing approaches can be leveraged to effectively drive industrialization and economic development in Sub-Saharan Africa. We propose chemicals manufacturing using prefabricated modules – which are constructed offsite in places with available human capital and transported to be assembled in places where they are needed – as a flexible and needed approach. However, Economy of Scale, which generally favors large-scale chemical manufacturing, poses as a major constraint to such modularization approach, especially given the presently small serviceable market sizes in Sub-Saharan Africa due to low purchasing power parity. We thus utilize mathematical modeling techniques to determine and establish scenarios for economic viability of the proposed approach, providing modeling frameworks and introducing measures for further studies in the process. We also provide and analyze exemplary flowsheets synthesized for a net-zero carbon emissions chemical manufacturing paradigm in the region.</p><p>This work concludes with a prefeasibility study of a chemical manufacturing project in Nigeria, as part of the author’s quest to build prefabricated modular plants across Africa. <i>Modular plants are attractive as they can be tuned to market demand of a developing market and region that needs them, putting less capital at risk.</i></p><p>This thesis is intended to be a vanguard of potential solutions to the complex challenges to industrialization in Sub-Saharan Africa. It endeavors to pave the way for addressing these issues through chemical manufacturing, offering valuable insights for sustainable progress.</p>
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Razvoj hemijske proizvodnje u doba antike na teritoriji današnje Srbije / Development of chemical production in the ancient history on the territory of present day SerbiaKalamković Snežana 30 September 2015 (has links)
<p>U ovom radu se proučava bogatstvo arheoloških lokaliteta sa teritorije današnje Republike Srbije sa aspekta razvoja hemijske proizvodnje, tj. materijalne kulture, koja je postignuta, za to doba, karakterističnom proizvodnjom metalne robe i građevinskog materijala. Uzorci koji su korišćeni, u većini slučajeva, nisu imali prethodni tretman ili su vađeni direktno iz ležišta arheoloških nalaza, uz odobrenje lokalnih i regionalnih muzeja: „Muzej Vojvodine” u Novom Sadu, „Zavičajni muzej” u Rumi, „Muzej Srema” u Sremskoj Mitrovici, „Muzej Viminacium” kod Kostolca, „Arheološki muzej Đerdapa” u Kladovu, Muzej „Đerdap 2” u Turn Severinu, Rumunija, „Muzej Krajine” u Negotinu, „Narodni muzej” u Zaječaru, „Muzej Mediana”, kraj Niša. Uzorci građevinskog materijala, opeke i vezivnog materijala potiču sa arheoloških lokaliteta: Mihajlovac-Klevora (<em>Clevora</em>), Trajanov most, Medijana (<em>Mediana</em>), Dijana <em>(Diana</em>), Najsus (<em>Naissus</em>), Feliks Romulijana <em>(Felix Romuliana</em>), Frateniza, Šarkamen, Hrtkovci i Viminacijum (<em>Viminacium</em>). Uzorci rimskih novčića su: iz perioda vladavine Flavia Julia Constantiusa, sa arheološkog lokaliteta Sirmium i drugih arheoloških lokaliteta današnje AP Vojvodine i sa arheoloških lokaliteta Istočne Srbije. Metode ispitivanja arheoloških uzoraka su: Mikroskopija, metalurški mikroskopi <em>Leitz</em>, <em>Orthoplan</em>, (x100) i <em>Carl Zeiss Jena</em> (x1000), gemološki mikroskop <em>Konig electronic </em>(200X), skenirajući elektronski mikroskop (<em>Scanning electronic microscopy</em>, SEM), JEOL JSM-6460LV; Spektroskopske metode, Energetski disperzivni spektroskop (<em>Energy dispersive spectroscopy</em>), EDS Oxford Instrument; Rendgenska fluorometrija <em>(X-ray fluorescence </em>XRF), <em>Thermo Fisher,</em> NITON XL 3t-950.</p><p><em>Poglavlja u radu</em>: I Teorijski deo: Teorijski deo čine dva poglavlja: uvod i opšti deo. <br />U prvom poglavlju su istaknuti razlozi i ciljevi odabira građevinskog materijala i metalnih novčića, kao polazna tačka istraživanja razvoja hemijske proizvodnje u doba antike na teritoriji današnje Srbije. Vojna inženjerija je bila inicijator razvoja tehnologije građevinskog materijala i metalnih novčića, dok je ostala hemijska proizvodnja bila na nivou zanatskih veština. Drugo poglavlje čini pet tema: Opši deo, Istorijske i društvene prilike u doba antike u Rimu i na teritoriji Balkana, Istorijske i društvene prilike u doba antike na teritoriji današnje Srbije, Proizvodnja opeke u doba antike i Metalurgija u doba antike na teritoriji današnje Srbije. II Metodologija istraživanja: Poglavlje Metodologija istraživanja obuhvata: Predmet istraživanja, Problem istraživanja, Cilj istraživanja, Zadatke istraživanja, Hipoteze. III <br />Ekspeimentalni deo: Eksperimentalni deo je podeljen u dve veće celine: Materijal i Metode. Celinu Materijal čini sedam odlomaka: Uzorkovanje materijala, Uzimanje uzoraka građevinskog materijala, Detekcija uzoraka građevinskog materijala vizuelnim putem, Kalupljenje uzoraka građevinskog materijala, Digitalna fotografija i optička mikroskopija uzoraka opeke, Detekcija metalnih novčića. Celinu Metode čini pet odlomaka: Terenska istraživanja, bibliografska, muzeološka, arhivska i kartografska istraživanja, Lociranje arheoloških lokaliteta (geofizička merenja), Fotografije arheoloških lokaliteta, Hemijske analize građevinskog materijala (Skenirajuća elektronska mikroskopija <em>(Scanning electronic microscopy</em>, SEM); Energijsko disperziona spektroskopija (<em>Energy dispersive spectroscopy</em>, EDS)), Hemijske analize metalnog novca (Mikroskopska analiza metalnog novca; Rendgenska fluoroscentna analiza (<em>X-ray fluorescence analysis</em>, XRF) metalnog novca). IV Diskusija rezultata istraživanja: U diskusiji rezultata istraživanja su: Prikaz, Interpretacija rezultata analiza; Diskusija dobijenih rezultata; Uporedne analize podataka. V Zaključak: Na osnovu istraživanja, konstatovano je da je hemijska proizvodnja u kasnoj antici, bila usmerena: ka dobijanju kvalitetnog građevinskog materijala i prema razvijenoj metalurgiji u kovnicama metalnog novca. VI Prilog: Prilozima se prikazuju: biografski i bibliografski prikazi arheologa, istraživača arheoloških lokaliteta, deo karte rimskih puteva „Tabula Peutingriana”, odlomak iz Vitruviusovih knjiga, izgled novčića sa likovima rimskih imperatora koji su rođeni na tlu današnje Republike Srbije, rad kojim se dokazuje da je opeku, najčešće, proizvodila vojska, podaci o glini, kao osnovnoj sirovini za proizvodnju opeke, mineralni sastav zemljišta, odrednica hemijskog sastava građevinskog materijala, rezultati hemijske analize ručno pravljene opeke, kao i rezultati hemijske analize savremene opeke. VII Literatura: U ovom radu je navedeno 445 naslova. </p><p>Ova doktorska teza objedinjuje regije koje su istraživali poznati naučnici, tj. sve veće arheološke lokalitete na teritoriji današnje Republike Srbije, tako da otvara put za dalja uporedna istraživanja i ispitivanja u hemiji, arheologiji, muzeologiji, arhitekturi, kao i poslovima restauracije, što, do sada, nije u dovoljnoj meri učinjeno. </p> / <p>This paper examines the wealth of archaeological sites on the territory of present-day Republic Serbia in terms of the development of chemical production, material culture, which is achieved, for the time, the typical manufacture of metal goods, and building materials. The samples that were used, in most cases, they had no prior treatment or were extracted directly from the deposits of archaeological finds, with the approval of local and regional museum: ”The Museum of Vojvodina” in Novi Sad, ”Heritage Museum” in Ruma, ”The Museum of Srem” in Sremska Mitrovica, ”Museum Viminacium” near Kostolac, ”Archaeological Museum Đerdap” in Kladovo, Museum ”Đerdap 2” in Drobeta Turn-Severin, Romania, ”Museum of Krajina” in Negotin, ”National Museum” in Zaječar, Museum ”Mediana”, near Niš. Samples of building materials, bricks and connective material originating from archaeological sites: Mihajlovac-Clevora, Trajanʼs Bridge, Mediana, Diana, Naissus, Felix Romuliana, Frateniza, Šarkamen, Hrtkovci and Viminacium. Samples of Roman coins are from the reign of Constantius Julia Flavia, the archaeological site of Sirmium and other archaeological sites today Vojvodina and from archaeological sites in Eastern Serbia (Prahovo). Test methods for archaeological samples are: Microscopy, Metallurgical Microscopes Leitz, ORHTOPLAN (x100) and Carl Zeiss Jena (x1000) Gemmological Konig Electronic Microscope (200X), Scanning Electron Microscope (SEM), JEOL JSM-6460LV; Spectroscopic Methods, Energy Dispersive Spectrometer (EDS), Oxford Instrument; X-Ray Fluorometry (XRF ), Thermo Fisher, NITON XL 3t- 950th. </p><p>Chapters in the paper: I Theoretical part: The theoretical part consists of two chapters: introduction and general part. In the first chapter of the prominent causes and objectives of the selection of building materials and coins, as a starting point for research on the development of chemical production in ancient times on the territory of Serbia. Army Corps of Engineers was the initiator of the technology of building materials and coins, and other chemical production was at the level of craft skills. The second section consists of five topics: General part, historical and social conditions in ancient times in Rome and in the Balkans, historical and social conditions in ancient times on the territory of Serbia, Manufacture of bricks in ancient times and Metallurgy in ancient times on the territory of Serbia. II Research Methodology: Research Methodology Chapter includes: The research, research problem, research objectives, the tasks of research hypotheses. Ekspeimentalni part III: The experimental part is divided into two major parts: Materials and Methods. Whole material consists of seven sections: Sampling materials, sampling of construction materials, building materials detection patterns visually, molding samples of building materials, digital photography and optical microscopy samples of bricks, Detection coins. Whole methods consists of five sections: Field research, bibliographic, museum, archival research and mapping, locating archaeological sites (geophysical measurements), photos of archaeological sites, the chemical analysis of building materials Scanning Electron Microscopy (SEM), Energy-Dispersive Spectroscopy (EDS), the chemical analysis of coins (Microscopic Analysis; X-ray Fluorescence Analysis (XRF). IV Discussion of research results: In the discussion of the research results are: Preview, interpretation of the results of analysis; Discussion of the results obtained; Comparative analysis of the data. In Conclusion: Based on the research, it was found that the chemical production in late antiquity, was directed: in obtaining high-quality building materials to advanced metallurgy in the mints coins. Appendix VI: Articles are displayed: biographical and bibliographical representations of archaeologists, researchers archaeological sites, part of the map of Roman roads „Tabula Peutingriana” section of Vitruviusovʼs books, coins with the appearance of the characters of Roman emperors were born in the territory of present-day Republic of Serbia, the work of proving that the bricks, usually producing army, data on clay, which is the basic raw material for the production of bricks, the mineral content of the soil, the term chemical composition of building materials, the results of chemical analysis handmade bricks, and the results of chemical analysis of contemporary brick. VII Literature: In this study indicated 445 titles. </p><p>This doctoral thesis combines the region explored by famous scientists, ie. all major archaeological sites on the territory of the Republic of Serbia, so that it opens the way for further comparative research and studies in chemistry, archeology, museology, architecture and restoration operations, which, so far, has not been sufficiently done.</p>
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