No description available.

<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 Ca²⁺ 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>

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.

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.

No description available.

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).

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.

Office of Chemical Emergency Preparedness and Prevention, U.S. Environmental Protection Agency, through a cooperative agreement

<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>

<p>U ovom radu se proučava bogatstvo arheolo&scaron;kih lokaliteta sa teritorije dana&scaron;nje&nbsp;Republike Srbije sa aspekta razvoja hemijske proizvodnje, tj. materijalne kulture, koja je&nbsp;postignuta, za to doba, karakterističnom proizvodnjom metalne robe i građevinskog&nbsp;materijala. Uzorci koji su kori&scaron;ćeni, u većini slučajeva, nisu imali prethodni tretman ili su&nbsp;vađeni direktno iz leži&scaron;ta arheolo&scaron;kih nalaza, uz odobrenje lokalnih i regionalnih muzeja:&nbsp;&bdquo;Muzej Vojvodine&rdquo; u Novom Sadu, &bdquo;Zavičajni muzej&rdquo; u Rumi, &bdquo;Muzej Srema&rdquo; u Sremskoj&nbsp;Mitrovici, &bdquo;Muzej Viminacium&rdquo; kod Kostolca, &bdquo;Arheolo&scaron;ki muzej Đerdapa&rdquo; u Kladovu,&nbsp;Muzej &bdquo;Đerdap 2&rdquo; u Turn Severinu, Rumunija, &nbsp;&bdquo;Muzej Krajine&rdquo; u Negotinu, &bdquo;Narodni&nbsp;muzej&rdquo; u Zaječaru, &bdquo;Muzej Mediana&rdquo;, kraj Ni&scaron;a. Uzorci građevinskog materijala, opeke i&nbsp;vezivnog materijala potiču sa arheolo&scaron;kih lokaliteta: Mihajlovac-Klevora (<em>Clevora</em>), Trajanov&nbsp;most, Medijana (<em>Mediana</em>), Dijana <em>(Diana</em>), Najsus (<em>Naissus</em>), Feliks Romulijana <em>(Felix&nbsp;Romuliana</em>), Frateniza, &Scaron;arkamen, Hrtkovci i Viminacijum (<em>Viminacium</em>). Uzorci rimskih&nbsp;novčića su: iz perioda vladavine Flavia Julia Constantiusa, sa arheolo&scaron;kog lokaliteta Sirmium&nbsp;i drugih arheolo&scaron;kih lokaliteta dana&scaron;nje AP Vojvodine i sa arheolo&scaron;kih lokaliteta Istočne&nbsp;Srbije. Metode ispitivanja arheolo&scaron;kih uzoraka su: Mikroskopija, metalur&scaron;ki mikroskopi&nbsp;<em>Leitz</em>, <em>Orthoplan</em>, (x100) i <em>Carl Zeiss Jena</em> (x1000), gemolo&scaron;ki mikroskop <em>Konig electronic&nbsp;</em>(200X), skenirajući elektronski mikroskop (<em>Scanning electronic microscopy</em>, SEM), JEOL&nbsp;JSM-6460LV; Spektroskopske metode, Energetski disperzivni spektroskop (<em>Energy&nbsp;dispersive spectroscopy</em>), EDS Oxford Instrument; Rendgenska fluorometrija <em>(X-ray&nbsp;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 op&scaron;ti deo.&nbsp;<br />U prvom poglavlju su istaknuti razlozi i ciljevi odabira građevinskog materijala i metalnih&nbsp;novčića, kao polazna tačka istraživanja razvoja hemijske proizvodnje u doba &nbsp;antike na&nbsp;teritoriji dana&scaron;nje Srbije. Vojna inženjerija je bila inicijator razvoja tehnologije građevinskog&nbsp;materijala i metalnih novčića, dok je ostala hemijska proizvodnja bila na nivou zanatskih&nbsp;ve&scaron;tina. Drugo poglavlje čini pet tema: Op&scaron;i deo, Istorijske i dru&scaron;tvene prilike u doba antike u&nbsp;Rimu i na teritoriji Balkana, Istorijske i dru&scaron;tvene prilike u doba antike na teritoriji dana&scaron;nje&nbsp;Srbije, Proizvodnja opeke u doba &nbsp;antike i Metalurgija u doba antike na teritoriji dana&scaron;nje&nbsp;Srbije. II Metodologija istraživanja: Poglavlje Metodologija istraživanja obuhvata: Predmet&nbsp;istraživanja, Problem istraživanja, Cilj istraživanja, Zadatke istraživanja, Hipoteze. III &nbsp;<br />Ekspeimentalni deo: Eksperimentalni deo je podeljen u dve veće celine: Materijal i Metode.&nbsp;Celinu Materijal čini sedam odlomaka: Uzorkovanje materijala, Uzimanje uzoraka&nbsp;građevinskog materijala, Detekcija uzoraka građevinskog materijala vizuelnim putem,&nbsp;Kalupljenje uzoraka građevinskog materijala, Digitalna fotografija i optička mikroskopija&nbsp;uzoraka opeke, Detekcija metalnih novčića. Celinu Metode čini pet odlomaka: Terenska&nbsp;istraživanja, bibliografska, muzeolo&scaron;ka, arhivska i kartografska istraživanja, Lociranje&nbsp;arheolo&scaron;kih lokaliteta (geofizička merenja), Fotografije arheolo&scaron;kih lokaliteta, Hemijske&nbsp;analize građevinskog materijala (Skenirajuća elektronska mikroskopija <em>(Scanning electronic&nbsp;microscopy</em>, SEM); Energijsko disperziona spektroskopija (<em>Energy dispersive spectroscopy</em>,&nbsp;EDS)), Hemijske analize metalnog novca (Mikroskopska analiza metalnog novca;&nbsp;Rendgenska fluoroscentna analiza (<em>X-ray fluorescence analysis</em>, XRF) metalnog novca). IV&nbsp;Diskusija rezultata istraživanja: U diskusiji rezultata istraživanja su: Prikaz, Interpretacija&nbsp;rezultata analiza; Diskusija dobijenih rezultata; Uporedne analize podataka. V Zaključak: Na&nbsp;osnovu istraživanja, konstatovano je da je hemijska proizvodnja u kasnoj antici, bila&nbsp;usmerena: ka dobijanju kvalitetnog građevinskog materijala i prema razvijenoj metalurgiji u&nbsp;kovnicama metalnog novca. VI Prilog: Prilozima se prikazuju: biografski i bibliografski&nbsp;prikazi arheologa, istraživača arheolo&scaron;kih lokaliteta, deo karte rimskih puteva &bdquo;Tabula&nbsp;Peutingriana&rdquo;, odlomak iz Vitruviusovih knjiga, izgled novčića sa likovima rimskih&nbsp;imperatora koji su rođeni na tlu dana&scaron;nje Republike Srbije, rad kojim se dokazuje da je&nbsp;opeku, najče&scaron;će, proizvodila vojska, podaci o glini, kao osnovnoj sirovini za proizvodnju&nbsp;opeke, mineralni sastav zemlji&scaron;ta, odrednica hemijskog sastava građevinskog materijala,&nbsp;rezultati hemijske analize ručno pravljene opeke, kao i rezultati hemijske analize savremene&nbsp;opeke. VII Literatura: U ovom radu je navedeno 445 naslova.&nbsp;</p><p>Ova doktorska teza objedinjuje regije koje su istraživali poznati naučnici, tj. sve veće&nbsp;arheolo&scaron;ke lokalitete na teritoriji dana&scaron;nje Republike Srbije, tako &nbsp;da otvara put za dalja&nbsp;uporedna istraživanja i ispitivanja u hemiji, arheologiji, muzeologiji, arhitekturi, kao i&nbsp;poslovima restauracije, &scaron;to, do sada, nije u dovoljnoj meri učinjeno.&nbsp;</p> / <p>This paper examines the wealth of archaeological sites on the territory of present-day&nbsp;Republic Serbia in terms of the development of chemical production, material &nbsp;culture, which&nbsp;is achieved, for the time, the typical manufacture of metal goods, and building materials. The&nbsp;samples that were used, in most cases, they had no prior treatment or were extracted directly&nbsp;from the deposits of archaeological finds, with the approval of local and regional museum:&nbsp;&rdquo;The Museum of Vojvodina&rdquo; in Novi Sad, &rdquo;Heritage Museum&rdquo; in Ruma, &rdquo;The Museum of&nbsp;Srem&rdquo; in Sremska Mitrovica, &rdquo;Museum Viminacium&rdquo; near Kostolac, &rdquo;Archaeological&nbsp;Museum Đerdap&rdquo; in Kladovo, Museum &rdquo;Đerdap 2&rdquo; in Drobeta Turn-Severin, Romania,&nbsp;&rdquo;Museum of Krajina&rdquo; in Negotin, &rdquo;National Museum&rdquo; in Zaječar, Museum &rdquo;Mediana&rdquo;, near&nbsp;Ni&scaron;. Samples of building materials, bricks and connective material originating from&nbsp;archaeological sites: Mihajlovac-Clevora, Trajanʼs Bridge, Mediana, Diana, Naissus, Felix&nbsp;Romuliana, Frateniza, &Scaron;arkamen, Hrtkovci and Viminacium. Samples of Roman coins are&nbsp;from the &nbsp;reign of Constantius Julia Flavia, the archaeological site of Sirmium and other&nbsp;archaeological sites today Vojvodina and from archaeological sites in Eastern Serbia&nbsp;(Prahovo). Test methods for archaeological samples are: Microscopy, Metallurgical&nbsp;Microscopes Leitz, ORHTOPLAN (x100) and Carl Zeiss Jena (x1000) Gemmological Konig&nbsp;Electronic Microscope (200X), Scanning Electron Microscope (SEM), JEOL JSM-6460LV;&nbsp;Spectroscopic Methods, Energy Dispersive Spectrometer (EDS), Oxford Instrument; X-Ray&nbsp;Fluorometry (XRF ), Thermo Fisher, NITON XL 3t- 950th.&nbsp;</p><p>Chapters in the paper: I Theoretical part: The theoretical part consists of two chapters:&nbsp;introduction and general part. In the first chapter of the prominent causes and objectives of&nbsp;the selection of building materials and coins, as a starting point for research on the&nbsp;development of chemical production in ancient times on the territory of Serbia. Army Corps&nbsp;of Engineers was the initiator of the technology of building materials and coins, and other&nbsp;chemical production was at the level of craft skills. The second section consists of five topics:&nbsp;General part, historical and social conditions in ancient times in Rome and in the Balkans,&nbsp;historical and social conditions in ancient times on the territory of Serbia, Manufacture of&nbsp;bricks in ancient times and Metallurgy in ancient times on the territory of Serbia. II Research&nbsp;Methodology: Research Methodology Chapter includes: The research, research problem,&nbsp;research objectives, the tasks of research hypotheses. Ekspeimentalni part III: The&nbsp;experimental part is divided into two major parts: Materials and Methods. Whole material&nbsp;consists of seven sections: Sampling materials, sampling of construction materials, building&nbsp;materials detection patterns visually, molding samples of building materials, digital&nbsp;photography &nbsp;and optical microscopy samples of bricks, Detection coins. Whole methods&nbsp;consists of five sections: Field research, bibliographic, museum, archival research and&nbsp;mapping, locating archaeological sites (geophysical measurements), photos of archaeological&nbsp;sites, the chemical analysis of building materials Scanning Electron Microscopy (SEM),&nbsp;Energy-Dispersive Spectroscopy (EDS), the chemical analysis of coins (Microscopic&nbsp;Analysis; X-ray Fluorescence Analysis (XRF). IV Discussion of research results: In the&nbsp;discussion of the research results are: Preview, interpretation of the results of analysis;&nbsp;Discussion of the results obtained; Comparative analysis of the data. In Conclusion: Based on&nbsp;the research, it was found that the chemical production in late antiquity, was directed: in&nbsp;obtaining high-quality building materials to advanced metallurgy in the mints coins.&nbsp;Appendix VI: Articles are displayed: biographical and bibliographical representations of&nbsp;archaeologists, researchers archaeological sites, part of the map of Roman roads &bdquo;Tabula&nbsp;Peutingriana&rdquo; section of &nbsp;Vitruviusovʼs books, coins with the appearance of the characters of&nbsp;Roman emperors were born in the territory of present-day Republic of Serbia, the work of&nbsp;proving that the bricks, usually producing army, data on clay, which is the basic raw material&nbsp;for the production of bricks, the mineral content of the soil, the term chemical composition &nbsp;of&nbsp;building materials, the results of chemical analysis handmade bricks, and the results of&nbsp;chemical analysis of contemporary brick. VII Literature: In this study indicated 445 titles.&nbsp;</p><p>This doctoral thesis combines the region explored by famous scientists, ie. all major&nbsp;archaeological sites on the territory of the Republic of Serbia, so that it opens the way for&nbsp;further comparative research and studies in chemistry, archeology, museology, architecture&nbsp;and restoration operations, which, so far, has not &nbsp;been sufficiently done.</p>