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1
Kochan, Mucahit. "Information Content of Iron Butterfly Arbitrage Bounds." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955071/.
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Informed traders trade options on underlying securities to lower transaction costs and increase financial leverage for price trend and variance strategies. Options markets play a significant role in price discovery by incorporating private information about future prices for an underlying security into option prices. I generate a new model-free volatility measure to calculate the "distance from arbitrage bounds" from minute-by-minute option series for the S&P 500 index and 30 individual underlying stocks. These iron butterfly arbitrage bounds (IBBs) use intraday call and put option prices from the Bloomberg database. Narrow and wide IBBs are expected to reveal the options market valuation of volatility by market participants. Data series is gathered by using successive one-minute intervals from the Bloomberg database. The data comprise the most recent bid and ask option prices and volumes. I collect S&P 500 index values and index options and use 30 underlying stock prices and option prices for the contracts that have the largest option trading volume during the sampling interval. These bid and ask prices reflect the information generated by intraday price pressures implied by S&P 500 index options or stock options. Consistent with the option micro-structure literature, I find that the IBB measure for actively traded stock options attains its highest level immediately after the open of the market, declines steadily throughout the first trading hour and remains relatively stable until market close. However, index IBBs behave differently. S&P 500 index option IBB attains its lowest level during the first hour of the trading day, then increases and remains relatively stable until market close. I present new evidence regarding the dynamic relation between stock returns and innovations in expected volatility by using the minute-by-minute change in implied volatility (IV) as a proxy. Unlike the relationship between individual stock returns and their respective changes in implied idiosyncratic volatility, I find that all the coefficients on the market volatility index (VIX) term are negative and significant. Therefore, the evidence supports the explanation that the negative relationship between stock returns and expected volatility innovations is primarily related to the systematic component of the expected volatility. I also test whether narrow and wide IBB values capture incremental information to explain the return-volatility relationship. Results indicate that neither narrow IBB nor wide IBB values provide additional information beyond that provided by VIX and IV. The results are robust to five-minute and ten-minute sampling frequencies.
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Mann, Georgianna Rhodes. "Effects of mineral content of bovine drinking water: Does iron content affect milk quality?" Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/22018.
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Implications of water chemistry on milk synthesis are not well described yet water is an important nutrient for dairy cattle. High mineral concentrations (>0.3 mg/kg Fe and others) may be associated with natural levels in ground water, contaminating sources, drought conditions, or storage systems. This study evaluated effects of added iron in bovine drinking water on milk composition (Ca, Cu, Fe, P) measured by inductively coupled plasma mass spectrometry and oxidative stability measured by thiobarbituric acid reactive substances assay for malondialdehyde (MDA), volatile chemistry and sensory analysis (triangle test). Prepared ferrous lactate treatments, corresponding to 0, 2, 5, and 12.5 mg/kg drinking water levels were given abomasally (10 L/d) to 4 lactating dairy cows over 4 periods (1 wk infusion/period) in a Latin square design. Milk was collected (d6 of infusion), processed (homogenized, pasteurized), and analyzed within 72 h of processing and 7 d of refrigerated storage. No differences in MDA (1.46�0.04 mg/kg) or iron (0.22�0.01 mg/kg) were observed in processed milk. Cross effects analysis (treatment*cow) showed significant differences in calcium, copper and iron (P < 0.05). Sensory differences (P < 0.05), in treatment vs. control, suggested iron from water sources contributes to milk flavor changes. A case study with high and low (0.99; 0.014 mg/kg) iron treatments revealed no significant differences (P > 0.05) in mineral composition (0.23�0.06 mg/kg Fe) or MDA (0.77�0.03 mg/kg) of raw milk. Iron added to milk causes changes in oxidation; high levels of iron in bovine drinking water may not have observed effects.Master of Science in Life Sciences
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Meskhidze, Nicholas. "Iron mobilization in mineral dust and the possible effect of Asian pollution on C-uptake in North Pacific Ocean." Diss., Available online, Georgia Institute of Technology, 2004:, 2003. http://etd.gatech.edu/theses/available/etd-04082004-180333/unrestricted/meskhidze%5fnicholas%5f200312%5fphd.pdf.
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Grzeskiewicz, Ronald. "Effect of hydrogen on the coefficient of friction of iron." Thesis, This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-04122010-083727/.
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Charman, R. G. "An investigation of iron in layer structured silicate minerals." Thesis, University of Greenwich, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383630.
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Clark, Eldred Merlyn. "Evaluation of Methods Used in Meat Iron Analyses and Iron Content of Raw, Cooked, and Cured Meats." DigitalCommons@USU, 1997. https://digitalcommons.usu.edu/etd/5438.
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This research project was divided into three parts. In the first part, heme, nonheme, and total iron methodologies for meats were evaluated. The accuracy, precision, and specificity of each method were determined by spike recoveries of heme and nonheme iron, and by analysis of National Institute of Science and Technology standard reference materials. The most reliable and practical methods were then used to determine the total, nonheme, and heme iron contents of various meats before and after cooking. The meats analyzed were beef, pork, lamb, chicken, and turkey. The wet-ashing technique was a novel procedure in which nitric acid was used to digest most of the solids followed by peroxy-monosulfuric acid to complete the digestion. Total iron values of the meats were consistent with those previously reported, but the percentage of heme iron in red meats was much greater than commonly assumed, both before and after cooking.
In the second part, the distribution of heme and total iron in heat-processed poultry products was investigated using light and dark chicken meat in the form of deep-flied chicken breasts and legs purchased from fast food restaurants and grocery stores in a ready-to-eat condition. Heme and total iron values were 1.7 ± 0.5 and 6.5 ± 2.0 μg Fe/g meat for light chicken meat and 7.6 ± 1.6 and 19.3 ± 2.2 μg Fe/g for dark chicken meat. Percent heme iron values averaged 29 and 40% for light and dark chicken meat, respectively.
In the third and final part, an application for the heme and nonheme iron data assembled above was developed to give dieticians an important tool in dietary formulations designed to maintain iron homeostasis. From the data it is evident that cooked light chicken meat, taken from the breast, would provide the lowest quantity of absorbable iron among the meats investigated and that ground beef, highest in heme iron, would provide the greatest quantity of bioavailable iron.
Additional research was performed on processed beef products. Cooked ground beef, frankfurters, beef steak, and roast beef were analyzed for heme and total iron. The different beef products contained similar amounts of total iron, 31.4 to 34.2 μg/g, but the heme iron content ranged from 6.2 μg/g in frankfurters to 36.3 μg/g in beef steak. Percent heme iron ranged from 33.0 to 63.8% in all meats. Total iron, heme iron, and percent heme iron varied significantly (P < 0.01) among meats, sources, and preparations. This research was published and has been reproduced in Appendix F.
7
Hoppler, Matthias. "Content and bioavailability of ferritin-bound iron in staple food crops /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=18038.
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Duan, Qing. "Genetic polymorphisms in bovine ferroportin are associated with beef iron content." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1476291.
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Siafakas, Dimitrios. "Investigation of Hydrogen and Nitrogen Content in Compacted Graphite Iron Production." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119086.
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The aim of this research, part of a wider program called SPOFIC, is to investigate how the casting procedure affects the concentration of hydrogen and nitrogen gases in Compacted Graphite Iron used for the production of truck cylinder blocks. Hydris equipment was used for the Hydrogen measurements and the Optical Emission Spectroscopy and combustion analysis methods were used for the nitrogen measurements. The experiment was performed in one of the cooperating foundries. It was found that Hydrogen content is increased during pouring of the melt into the mold but nitrogen content does not seem to be effected by the process. In both cases the gas content never exceeded the solubility limit. The results are comparable with results from similar researches regarding Gray Cast Iron.SPOFIC
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Tian, Feng, and n/a. "The organic complexation of iron in seawaters around New Zealand." University of Otago. Department of Chemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070117.091325.
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This project aimed to characterise the organic speciation of iron in various oceanic waters associated with the New Zealand marine environment, and to examine the possible production of natural organic Fe-binding ligands by the Southern Ocean phytoplankton Phaeocystis antarctica. The location of New Zealand at the edge of the Southern Ocean provides a natural laboratory for studying ocean processes in a variety of oceanic conditions.
A time series of a surface transect across the Otago Continental Shelf was undertaken between April 2002 and January 2005 to measure the organic complexation of iron, hydrographic parameters and macronutrient concentrations. The study area contains three distinct water masses: 1) neritic water; 2) the Southland Current, derived from the Subtropical Surface Water (STW); 3) Subantarctic Surface Water (SASW). Hydrological measurements outlined the positions of the three water masses as being fixed within predictable boundaries. Variations in nutrient concentrations in the study area indicated that SASW is the predominant source of nitrate and phosphate to the shelf. Dissolved iron concentrations dropped sharply seaward from several nanomolar to sub-nanomolar levels. The dissolved iron was fully complexed with strong organic ligands in all three water masses, and the ligand concentrations also showed a slightly seaward decreasing trend. Trends in dissolved iron and the iron-binding ligand concentrations related to season were only obvious in neritic waters. Concentration maxima occurred during late spring and summer months, and concentration minima occurred in the middle of each year (winter months). Dissolved iron concentration was low (~0.1 nM) in SASW year round. Data from the present study are in support of that the SASW as a whole is classified as a high nitrate low chlorophyll (HNLC) water body and has an iron-limited phytoplankton population.
East of the New Zealand landmass, the Subtropical Convergence (STC) is topographically locked to the Chatham Rise. This is a dynamic region of enhanced primary production (Bradford-Grieve et al., 1997), which separates macronutrient-depleted STW from macronutrient-replete SASW. Dissolved iron concentrations were low (~0.1-0.2 nM) in SASW, while elevated dissolved iron concentrations were observed at the north flank of the Chatham Rise. The iron data imply that the regional currents may be an important vehicle for transporting the elevated iron across the front. Total dissolved iron-binding ligand concentrations were consistently higher (~0.5 nM) in the STW and STC waters than in SASW. The discrepancy in the ligand concentrations between STW and SASW may reflect a different contribution to the ligand pool from the local planktonic community.
The organic complexation of iron in the oligotrophic subtropical water columns in the Tasman Sea was also studied and comparison of waters to the north and south of the Tasman front were reported. The iron speciation data imply the potential biological origin for the iron-binding ligands, and the difference in ligand concentrations across the Tasman Front may represent slight differences in algal biomass.
A limited investigation to examine the production of natural organic iron-binding ligands by the Southern Ocean phytoplankton Phaeocystis antarctica was undertaken in laboratory culture experiments. Release of nanomolar levels of a strong iron-binding ligand was detected by cathodic stripping voltammetry (CSV) even under relatively high iron concentrations (> 1nM). The estimated iron binding strength for the ligands was similar to those observed in the open ocean. Moreover, the kinetic data suggested the presence of another weaker ligand class, which had a higher Fe concentration (>2 nM) and was not detectable by the CSV ligand titration technique.
Our field observations and culture experiment results suggest that the Fe-binding ligands are biologically produced. It appears algae engineer their environment to make Fe more available/accessible for longer by producing these ligands. Therefore, the organic speciation of Fe plays a very important role in the sustained nutrition of ocean primary productivity and must be accounted for in geochemical modelling.
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Nikolaiczuk, Marcia Jane. "Relative availability of iron to rats from beef, soy protein and a beef-soy protein mixture as determined by iron repletion assay." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24874.
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Male weanling Wistar rats were fed a low-iron basal diet for 3 weeks. The iron depleted rats were then divided into 9 groups according to a randomized block design based on body weight. During the repletion period of 2 weeks, one group was fed the low-iron basal diet. The other eight groups received either the basal diet to which was added 5, 10, 15, 20 or 25 mg iron per kg diet as ferrous sulfate or test source diets formulated to provide a total of 15 mg iron per kg diet from either freeze-dried ground beef, textured defatted soy flour product or a 2.3:1 (w/w) mixture of beef and soy product. All diets were isocaloric and isonitrogenous. The relative biological value (RBV) of iron in the test source diet was calculated as the ratio of the amounts of iron from the reference source (ferrous sulfate) and the test source diet required to give the same response in hemoglobin or hematocrit. The RBVs ± 95% confidence limits, calculated on the basis of final hemoglobin levels and hematocrit values, were respectively: freeze-dried ground beef, 56 ± 7 % and 62 ± 7 %; fortified textured defatted soy flour product, 81 ± 10 % and 79 ± 10 %; 2.3:1 (w/w) mixture of freeze-dried ground beef and soy flour product, 65 ± 6 % and 68 ± 6 %. The RBVs obtained for the iron in beef and for that in the soy flour product suggest that the anemic rat might not be a suitable model for normal man when screening such foods for their available iron. In normal man, the absorption of the iron in beef is comparable to that of inorganic reference iron, while that in textured soy flour is about one third.Land and Food Systems, Faculty of
Graduate
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Kirby, A. W. "The reduction of iron content in ferrochromium via the nitriding/leaching route." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377841.
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Ozcan, Alper. "The Effect Of Sn Content And Isothermal Transformation Temperature On The Mechanical Properties Of Austempered Ductile Cast Iron." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1055359/index.pdf.
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In this study the effects of Sn content and isothermal transformation temperature on the ultimate tensile strength (UTS), elongation and hardness of austempered ductile cast iron (ADI) was investigated. To determine the possible effect of Sn on these properties the Sn content of standard GGG30, GGG40 and GGG50 materials were taken as reference, whose chemical compositions vary from 0,016 to 0,050% in terms of Sn. However the Sn content was increased to a maximum of 0,26% for investigating the effect of Sn on mechanical properties. The test specimens were obtained from standard 1-in Y-blocks and austenitized at 925oC for 1 hour and austempered at 350oC,375oC, 400oC and 420oC for 60 minutes in a salt bath.
Microstructural examination of the specimens were also done. To determine the amount of retained austenite of the specimens X-Ray analyses were used. As a result of the study The UTS increases up to 0,1% Sn and then levels off. A similar behavior is observed in the variation of hardness. Percent elongation decreases and falls to a minimum around 0,1% Sn, from this point on, a slight increase is observed. Strength and hardness increase while percent elongation decreases with decreasing temperatures.
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Amarakoon, Amarakoon Rajapakse Wasala Mohotti Mudiyanselage Darshika. "Iron Biofortification Potential of Field Pea (Pisum Sativum L.)." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26518.
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Iron (Fe) deficiency affects more than 3 billion of the global population. The objectives of this study were to (1) determine the genetic and environmental variation of seed Fe concentration and food matrix factors that govern Fe bioavailability in field peas (Pisum sativum L.) grown in North Dakota, USA in 2010 and 2011, and (2) determine the genetic variation of Fe uptake by field pea grown under greenhouse conditions with different Fe treatments. Seed Fe concentration in field pea samples from the field study ranged between 46-53 mg/kg with a mean of 51 mg/kg. Mean concentrations of the food matrix factors in those field peas were as follows: phytic acid=5.1 mg/g, xanthophyll=17.3 mg/100 g, canthaxanthin=86.8 mg/100 g, beta-carotene=516.8 ?g/100 g, kestose=1697 mg/100g, quercetin=54.3 mg/100 g, and ferulic acid=46.9 mg/100 g. DS Admiral and CDC Golden showed high concentrations of Fe promoter compounds and low concentrations of phytic acid. DS Admiral showed high Fe uptake with increasing Fe fertilizer rates in the greenhouse study. Therefore, DS Admiral and CDC Golden could be potential field pea genotypes for future Fe biofortification efforts.
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Griffiths, P. D. "Alterations in neurotransmitter receptors and iron content in Parkinson's disease and Alzheimer's disease." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328333.
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Moser, Martin. "Studies on iron supply in veal calves and on transferrin levels in cattle /." [S.l : s.n.], 1994. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Deursen, Cornelius Thomas Bernardus Maria van. "Iron content of liver tissue a biochemical, histological and clinical study, especially in hereditary haemochromatosis /." [Maastricht : Maastricht : Rijksuniversiteit Limburg] ; University Library, Maastricht University [Host], 1989. http://arno.unimaas.nl/show.cgi?fid=5456.
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Yao, Yingshan. "The influence of niobium content and cooling rate on mechanical properties of grey cast iron." Thesis, KTH, Materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-244999.
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This project mainly investigated how the niobium(Nb) content influences the microstructure and mechanical properties of grey cast iron. Considering the mechanism, the study also analyzes the relationship between microstructure and mechanical properties. Generally, the work is based on 127 test bars/samples from two cylinder heads and three batches of plates, which were studied by measuring tensile strength, microhardness, graphite size, carbide amount and chemistry. The result data has been evaluated with statistical methods. The experiments mainly included the preparation of the samples for test and analysis. The mechanical properties in this study are evaluated by the tensile strength of the grey cast iron. Meanwhile, various microscopies were applied to observe how niobium and cooling rate influence the microstructure. Finally, from the analysis results, it tells that the niobium does affect the tensile strength of grey cast iron. Higher the niobium content is, higher the tensile strength is. The computed result based on the data also shows niobium’s strong effect. The faster cooling rate will increase the tensile strength and pearlite microhardness of grey cast iron as well. The carbide amount of grey cast iron can be increased by the addition of niobium content. Furthermore, some future work needs to be done to explain the unsolved problem in this result. The reasons of why a specific position A-2-d of plates has high values of tensile strength demand more microstructure investigation. For the niobium influence, more experiments and data containing a larger range of niobium content also need to be done to prove the mathematics results in this report.Detta projekt undersökte huvudsakligen hur innehållet av niob (Nb) påverkar gråstålens mikrostruktur och mekaniska egenskaper. Med tanke på mekanismen analyserar undersökningen även förhållandet mellan mikrostruktur och mekaniska egenskaper. Arbetet baseras i allmänhet på 127 provstänger / prover från två cylinderhuvuden och tre satser av plattor, vilka studerades genom mätning av draghållfasthet, mikrohårdhet, grafitstorlek, karbidmängd och kemi. Resultatdata har utvärderats med statistiska metoder. Experimenten inbegriper huvudsakligen beredningen av proven för test och analys. De mekaniska egenskaperna i denna studie utvärderas av gråstålets draghållfasthet. Under tiden applicerades olika mikroskopier för att observera hur niob- och kylhastigheten påverkar mikrostrukturen. Slutligen, från analysresultaten, berättar den att niobet påverkar draghållfastheten hos grågjutjärn. Ju högre niobinnehållet är, desto högre är draghållfastheten. Det beräknade resultatet baserat på data visar också niobins starka effekt. Den snabbare kylhastigheten ökar också draghållfastheten och pearliten-mikrohårdheten hos grågjutjärn. Karbidmängden av grågjutjärn kan ökas genom tillsats av niobhalt. Vidare måste vissa framtida arbeten göras för att förklara det olösta problemet i detta resultat. Skälen till varför en specifik position A-2-d av plattor har höga dragkrafter kräver mer mikrostrukturundersökning. För niobinpåverkan måste fler experiment och data som innehåller ett större antal niobinnehåll också göras för att bevisa matematikresultaten i denna rapport.
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Shorney, Holly L. "The performance of free chlorine and chlorine dioxide oxidation and/or alum coagulation for the removal of complexed Fe(II) from drinking water." Thesis, Virginia Tech, 1992. http://hdl.handle.net/10919/44744.
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Past research regarding complexed iron has focused on the resistance to and kinetics of oxidation by O₂(aq) and the extent of stabilization. The 0.45 um filter was typically used to differentiate between dissolved and particulate iron.
This research investigated Fe(II) oxidation by free chlorine and ClO₂ in the presence of DOC by varying the pH, DOC to Fe ratios, DOC sources, oxidant dosages, and contact time. Complexed iron removal by alum coagulation with and without oxidant addition was also examined. Particulate, colloidal, and soluble iron were differentiated by the use of 0.2 um filters and 100K ultrafilters.
Ultrafiltration and oxidation studies revealed that, at the DOC-to-iron ratios used for this research, not all of the Fe(II) in solution was actually complexed. Thus, oxidation studies represented the oxidation of uncomplexed Fe(II) to Fe(III), which was then complexed by the higher molecular weight DOC.
Results indicated that particulate iron formation (as defined as retention by a 0.2 um filter) was a function of the DOC source and oxidant used for testing. The formation of colloidal iron (as defined by retention on 100K ultrafilter) due to oxidation was dependent upon the initial DOC-to-iron ratio and the DOC source. A correlation between DOC adsorption to iron oxide solids and the solution pH, initial DOC-to-iron ratio, and the oxidant used was also evident. Complexed Fe(II) was removed from solution by alum coagulation. Oxidant addition to alum coagulation was necessary to effectively remove uncomplexed Fe(II) (in the presence of DOC) from solution.Master of Science
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Jin, Ji-yun. "Boron chemistry in selected Virginia soils and hydroxy aluminum and iron systems." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54304.
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Greenhouse and laboratory experiments were conducted to investigate the distribution of native B, the availability of native and applied B in 14 Virginia soils and the specific reactions of B in soil and hydroxy Al and Fe systems.
Total B in the 14 soils ranged from 21.5 to 96.3 mg kg⁻¹. Only a small portion of the total B was in soil solution, non-specifically and specifically adsorbed forms and Mn minerals. These fractions of B are readily available to plants. A large part of the total B was associated with non-crystalline and crystalline Al and Fe minerals and soil silicates. These forms of B contribute little to B absorption by plants. Hot water soluble B, NH₄-acetate extractable B, mannitol exchangeable B and Mehlich III extractable B from the soils closely correlated with the concentrations in corn plants from native B in the greenhouse experiment. A yield response of corn plants to B application did not occur on the soils.
Both tissue B concentration from applied B and maximum B adsorption by the soils closely correlated with soil clay, hydroxylamine hydrochloride extractable Mn and NH₄—oxalate (pH 3.25) extractable Al and Fe (under UV light). These data indicated that soil clay and Al-, Fe- and Mn-oxides and hydroxides have high affinities to adsorb B in plant unavailable forms.
Boron adsorption on both gibbsite and goethite was pH and temperature dependent. At pH 6.5, boric acid was major species in the system and B was absorbed by the negatively charged surface of gibbsite and the positively charged surface of goethite. At pH 10, borate was primarily species in the system and B was adsorbed on negatively charged surfaces of both minerals. Boron adsorption was greater at pH 10 than at pH 6.5. An increase in temperature increased B adsorption on both minerals at both pH levels. This indicated that the B adsorption was an exothermic process. Boron adsorption on gibbsite and goethite shifted the ZPC of the minerals downward. This verified that specific B adsorption occurred on the surfaces. Aluminum substitution in goethite increased the affinity of the surface for B adsorption.Ph. D.
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Cangialosi, Michael Vincent. "The Effect of Clay Content and Iron Oxyhydroxide Coatings on the Dielectric Properties of Quartz Sand." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/42579.
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Dielectric constant is a physical property of soil that is often measured using non-invasive geophysical techniques in subsurface characterization studies. A proper understanding of dielectric responses allows investigators to make measurements that might otherwise require more invasive and/or destructive methods. Previous studies have suggested that dielectric models could be refined by accounting for the contributions of different types of mineral constituents that affect the ratio and properties of bound and bulk water. This study tested the hypothesis that the dielectric responses of porous materials are mineral-specific through differences in surface area and chemistry. An experimental design was developed to test the dielectric behavior of pure quartz sand (Control), quartz sand/kaolin clay mixtures and ferric oxyhydroxide coated quartz sand. Results from the experiments show that the dielectric responses of quartz-clay and iron oxyhydroxide modified samples are not significantly different from the pure quartz Control. Increasing clay content in quartz sands leads to a vertical displacement between fitted polynomials. The results suggest that the classic interpretation for the curvature of dielectric responses appears to be incorrect. The curvature of dielectric responses at low water contents appears to be controlled by unknown parameters other than bound water. A re-examination of the experimental procedure proposed in this study and past studies shows that a properly designed study of bound water effects on dielectric responses has not yet been conductMaster of Science
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Huang, Rong [Verfasser], and Daniel [Akademischer Betreuer] Frost. "Bridgmanite crystal chemistry and iron content in the Earthʹs lower mantle / Rong Huang ; Betreuer: Daniel Frost." Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1204997519/34.
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Moffat, Christopher. "Acclimation to iron limitation in the haptophyte Coccolithus pelagicus : a molecular investigation." Thesis, University of Stirling, 2008. http://hdl.handle.net/1893/1751.
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Phytoplankton growth is iron limited in at least 20% of the world’s oceans. Iron is an important nutrient required to synthesise enzymes necessary for photosynthesis, respiration, and nitrogen assimilation. Due to its low solubility in seawater, iron limitation of phytoplankton production has been the focus of much recent research. These organisms secrete ligands in order to solubilise the available iron, but not all of the iron dissolved in seawater is biologically available. In this study a molecular based approach was employed to investigate the acclimation of the marine haptophyte Coccolithus pelagicus to iron limitation. Using two dimensional electrophoresis, subtractive cDNA hybridisation, and RT real time PCR, changes in the proteome and in gene expression were examined. Iron limited cells were characterised by slower specific growth rates, lower chlorophyll a concentrations per unit biomass and less extensive calcification relative to iron replete cells. Addition of iron to iron limited cultures resulted in increased specific growth rates and increased chlorophyll a concentration per unit biomass. A subtracted cDNA library revealed seventeen identifiable sequences of which photosystem I protein E (PsaE), a fucoxanthin binding protein transcript, two chlorophyll binding proteins and a predicted membrane protein were shown to be up-regulated in iron-limited cells to varying extents. Two dimensional SDS PAGE revealed 11 differentially expressed proteins in iron limited cells and 1 highly expressed protein exclusive to iron replete cells. The potential utility of each of these as biomarkers of iron-limitation/iron sufficiency for natural populations of coccolithophorids like Coccolithus pelagicus is discussed.
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Tadayyon, Ali, Sedigheh Beheshti, and Mohammad Pessarakli. "Effects of sprayed humic acid, iron, and zinc on quantitative and qualitative characteristics of niger plant ( Guizotia abyssinica L.)." Taylor & Francis, 2017. http://hdl.handle.net/10150/626135.
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In order to investigate the effect of foliar application of organic fertilizer and micronutrients on
quantitative and qualitative characteristics of Niger plant, a field experiment was conducted in a complete randomized block design with three replications at Shahrekord University Research
Farm during the years 2013-2014. Treatments included three levels of humic acid (1, 3, and 6
liters of humic acid per hectare), iron (4 parts per million, ppm), zinc (4 parts per million, ppm) and control (without humic acid iron, and zinc). In this experiment, traits of the number of heads
per plant, seeds number per head, 1000 seeds' weight, grain yield, and also oil and protein
content were evaluated. The findings showed that foliar application of humic acid, zinc and iron
resulted in a significant increase in all analyzed traits. The most significant plant response was
obtained with the use of 6 liters humic acid per hectare, and the second most significant plant
response was seen with the sprayed zinc treatment which was probably due to limited absorption and deficiency of these elements in the tested soil.
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Batchily, Abdul Karim 1952. "Use of Chroma Meter color measurements to evaluate the organic carbon, iron, and water content of soils." Thesis, The University of Arizona, 1991. http://hdl.handle.net/10150/277947.
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The soil color components of 127 samples from five Arizona Agricultural Research Centers and 52 WEPP samples occurring in various parts of the U.S.A. were evaluated using a Minolta Chroma Meter. This instrument is designed to minimize the variability in color determination utilizing a built-in light source to generate a primary source of radiation. Simple and multiple linear regression equations relating Hue, Value, and Chroma color components were obtained to predict the organic carbon and iron content of these soils. The results show that using global data is less reliable than specific groupings of soils. Moist value and moist chroma moist are the two most important color components in estimating the organic carbon content of soils. Chroma and Hue were highly correlated to iron at all moisture levels. Chroma was least affected by soil moisture, but Value and Hue consistently decreased for all soils.
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Thyrén, Linnea. "Plant-based meat substitutes and their nutritional composition : A study on iron content, zinc content, calcium content and protein quality in meatballs and plant-based substitutes and how they contribute to the goal of reaching recommended daily intakes." Thesis, Linnéuniversitetet, Institutionen för kemi och biomedicin (KOB), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96761.
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The purpose of this thesis was to study similarities and differences between a meat product and its plant-based substitutes in terms of how they enable people to reach the recommended daily intakes (RDI). The meat product included in the study were meatballs and its substitutes were three different plant-based alternatives. One was mainly based on soy, one on pea protein and one consisted of several different vegetables. The parameters studied were iron, zinc and calcium content as well as protein quality. By analyzing the four different products with flame atomic absorption spectroscopy (FAAS), the mineral content was calculated and protein quality was determined using amino acid analyzis carried out by the laboratory analysis company ALS. The method used to determine protein quality was DIAAS (Digestible Indispensable Amino Acid Score). Example meals and example days were created to visualize any differences and similarities when the products were put in a wider perspective. The results showed that there were differences between the products when they were compared individually, but that the differences were negligible when the products were included in an example meal or example day. This indicates that the products fulfill comparable dietary requirements and that the plant-based products were good substitutes for the meat product. The soy-based product was the best plant-based alternative when it comes to iron content, calcium content and protein quality. However, the soy product and the remaining substitutes reached recommended intakes for the same parameters when included in example days, which shows that the differences between the products are only present when analyzed individually.
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Westphal, Karsten, Ralf Klose, and Manfred Golze. "Eisengehalt von Fleisch - Ermittlung des Eisengehalts im Fleisch verschiedener Tierarten." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-25410.
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Der Bericht beinhaltet Ergebnisse von Fleischuntersuchungen auf den Eisengehalt.
Untersucht wurden 308 Schweinefleischproben und etwa 300 Fleischproben der Tierarten Rind, Bison, Auerochse, Büffel, Schaf, Ziege, Kaninchen, Wildschwein, Rehwild, Rotwild und Fasan.
Die sächsischen Ergebnisse bestätigen Untersuchungen anderer Bundesländer und belegen den starken Rückgang des Eisengehaltes im Schweinefleisch. Er lag im Mittel bei 4,1 mg/kg Frischmasse (FM). Vor 30 Jahren lag der Eisengehalt noch bei 18 mg/kg - 25 mg/kg.
Das Fleisch von Tierarten mit sogenanntem rotem Fleisch wie Rind, Schaf, Büffel, Bison, Auerochse, Reh- und Rotwild weist erwartungsgemäß einen hohen Eisengehalt (17 mg/kg FM - 33 mg/kg FM) auf.
Farbuntersuchungen zeigten, dass der Eisengehalt eine Abhängigkeit zur Farbhelligkeit und zum Rotton des Fleisches aufweist. Je dunkler bzw. je intensiver der Rotton des Fleisches ist, desto höher der Eisengehalt.
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Åberg, Franz. "Mineralogical Study of Manganese Bearing Skarn Minerals and Manganese Content in Magnetite in the Dannemora Skarn Iron Ore Deposit." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-263473.
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The Dannemora skarn iron ore deposit is located in the northeastern part of Bergslagen. The deposit has been mined from the 1400’s and stopped in 1992, the mine was reopen in 2012 and it will close in 2015. The Dannemora deposit is hosted by 1.9 Ga old sedimentary and volcanic rocks. The deposit consists of both manganese rich and manganese poor iron ore. The purpose of this study is to investigate the controlling factors for manganese content in both magnetite and surrounding silicate minerals, especially when garnets is present. Also the mineral assemblage and association with different host rocks lithologies shall be investigated. Petrographical and chemical studies indicate the occurrence of both calcic amphibole and Mg-Fe-Mn-Li type amphibole. The calcic amphibole is found in the majority of the samples and is dominant in manganese poor samples where as Mg-Fe-Mn-Li-type amphibole is more abundant in the manganese rich samples. Generally in the manganese rich samples garnet and epidote become more abundant, particularly if the sample is taken close to a volcanic section.Skarn-järnmalmsfyndigheten i Dannemora är belägen i den nordöstra delen av Bergslagen. Järnmalm och mindre sulfidmineraliseringar har blivit brutna sedan 1400-talet. Gruvan stängde 1992 men togs i produktion igen under 2012. Gruvan stängs återigen under 2015. Fyndigheten är omgiven av 1.9 Ga gamla sedimentära och vulkaniska bergarter. Järnmalmsfyndigheten innehåller både manganrika och manganfattiga järnmalmer. Syftet med denna studie är att undersöka varför fyndigheten har förhöjda halter av mangan. Förändringar av manganhalter och olika värdbergarter borde ge en annorlunda mineralsammansättning i de olika miljöerna. För att svara på dessa frågor skall både mikroskopiska och kemiska undersökningar göras för att bestämma och identifiera olika mineralogiska associationer. Petrografiska och kemiska studier indikerar två olika huvudtyper av amfiboler: kalciumhaltiga amfiboler och Mg-Fe-Mn-Li-amfiboler. Kalciumamfibolerna är generellt mer spridda i proverna medan Mg-Fe-Mn-Li-amfibolerna är mer koncentrerade till de mer manganrika sektionerna. När koncentrationen av mangan är högre blir granater och även epidot och olivin vanligare, speciellt närmare vulkaniska bergarter.
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Shin, Dae Keun. "Antioxidant, color and sensory properties of sorghum bran in pre-cooked ground beef patties varying in fat and iron content." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1120.
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Ram, Gokul, and Vishnu Harikrishnan. "INFLUENCE OF CARBON CONTENT AND COOLING CONDITIONS ON THE THERMAL CONDUCTIVITY AND TENSILE STRENGTH OF HIGH SILICON LAMELLAR GRAPHITE IRON." Thesis, Tekniska Högskolan, JTH, Material och tillverkning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-51152.
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Much study has been carried out to determine the properties of Lamellar Graphite Iron (LGI) or grey iron and their relations to factors such as the cooling rate, the dendrite morphology, the pouring temperature, and so on. However, there hasn’t been much comprehensive study on the properties of LGI outside the generally used and accepted composition, with 1 to 3% Silicon. The scope of this study is to measure and evaluate the thermal conductivity and tensile strength of LGI, for a higher concentration of Si and different carbon contents. The concentration of Si aimed for was 4% but the concentration obtained after spectroscopy was between 4.1% to 4.15%. There are two hypereutectic, one near-eutectic and three hypoeutectic samples considered and these six chemical compositions were cast under different cooling conditions . The cooling time has been varied by providing different molds of 30mm, 55mm, and 80mm diameter cylinders respectively, for all the six sample compositions. The microstructure analysis carried out studies the segregation of Si, the graphite morphology, primary austenite morphology. These factors are then compared to the thermal and tensile behavior measured in this study. It can be observed that the thermal conductivity studied in the present work has a direct correlation for a higher Si content and tends to be greater than the thermal conductivity values observed from other studies with lower content Of Si. However, the conductivity shows an inverse relation with the cooling rate and is maximum for the samples with the lowest cooling rate. The tensile strength, on the other hand, seems to have a lower value than that observed in previous studies for LGI with 1 to 3% Si, but shows a direct correlation with the cooling rate. The mean area fraction of dendrites obtained and the mean interdendritic hydraulic diameter is also measured and their influence on the properties are also studied. The addition of more Si has greatly favored the thermal behavior positively but has also reduced the tensile strength.
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Isaksson, Jenny. "Slag Cleaning of a Reduced Iron Silicate Slag by Settling : Influence of Process Parameters and Slag Modification on Copper Content." Licentiate thesis, Luleå tekniska universitet, Mineralteknik och metallurgi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-84798.
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During the pyrometallurgical extraction of copper, a significant part of the copper is lost with discard slag, which decreases profits, overall copper recovery, and efficiency of raw material usage. Smelting furnace slag usually has a copper content that is close to or higher than that of copper ores. The investigation of copper losses to slag is thus a task of practical significance, as the ore grades are depleting. Slag cleaning, e.g., a settling furnace, can reduce copper losses to slag as the mechanically suspended copper-containing droplets separate from slag under the action of gravity and can hence be recovered. An industrial trial was conducted in an electric settling furnace with slag originating from an electric smelting furnace and processed in a zinc fuming furnace. The trial was conducted to increase the understanding of copper losses to slag and how the process parameters temperature and settling time influence the slag copper content. The obtained slag samples were also evaluated to gain better insights as to the settling mechanism and, if any, factors that hinder the copper phases from settling. Slag modification with CaO was also evaluated to investigate how the modification influences the settling of copper phases and, thus, the final slag copper content. Samples collected during the industrial trial were the basis for the evaluation in the current work. The samples came from batches with varying temperatures, settling times, and CaO content collected at four different sample positions. Instrumental techniques, including XRF, FAAS, ICP-SFMS, and SEM-EDS, were used to analyze the chemical compositions of the samples and the appearance of copper and associated phases. The results indicated that the copper content of outgoing slag increased with increasing temperature in the evaluated interval. The copper content was also concluded to be more strongly affected by the temperature compared to the settling time. Regulating the temperature to the lower temperature interval in the settling furnace could thus decrease the final slag copper content. During the slag characterization, it was found that suspended copper-containing phases were hindered from settling, due to the attachment to solid phases and gas bubbles in the slag. By controlling and minimizing the presence of the bottom buildup and thus solid phases in the slag, the copper content can be decreased. The results indicated that the CaO slag modification decreased the final slag copper content, and can thus be used as a modifier for increased settling.
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Feng, Huan. "Preparation of glass-ceramics largely using steelmaking slags and study on the effect of iron content on properties of glass-ceramics." Scholarly Commons, 2014. https://scholarlycommons.pacific.edu/uop_etds/219.
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Glass-ceramics were prepared using steelmaking industry waste containing high iron content based on powder sintering and crystallization method. Anthracite was used in varying amounts as the reducing agent to recover iron in raw materials. X-ray diffraction analysis (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray spectrometer (EDX) were used to study the microstructure of glass-ceramics formed. Bending strength and micro-harness of the samples were compared. When 12g of anthracite was used, ionic iron (Fe 2+ /Fe 3+ ) content was reduced to 4.7% and total iron content was reduced to 8.0% in parent glass. The main crystalline phases formed were diopside and augite. Crystalline phases were well-distributed ranging between 0.2 to 0.4 µm after crystallization. A maximum bending strength of 91MPa and a maximum micro-hardness of 3466MPa were achieved. Effect of Al 2 O 3 content on glass-ceramics was studied. Both average bending strength and average micro-hardness of glass-ceramics with 15% Al 2 O 3 content were higher than the glass-ceramics with 6% Al 2 O 3 content. Blast furnace dust was used as both a reducing agent to recover iron and a raw material to prepare glass-ceramics. Compared with glass-ceramics using anthracite as the reducing agent, average bending strength of glass-ceramics formed using BF dust was lower, while average micro-hardness was higher.
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Rauch, Jeanne-Marie. "Comportement électrochimique d'électrolytes Zinc Fer à haute teneur en Fer, germination et effet des courants pulsés." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2022. http://www.theses.fr/2022UBFCD031.
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La mise au point de revêtements anticorrosion présente à la fois un enjeu économique et un défi environnemental. En effet de nombreuses contraintes sont apparues dans le domaine des traitements de surface au cours des dernières décennies, du fait de la mise en application de restrictions sur l'utilisation de certains produits. Ainsi, la directive européenne RoHS (Restriction of the use of certain Hazardous Substances) limite l'utilisation de substances dangereuses au niveau des équipements électrique et électroniques. La règlementation REACH quant à elle, évalue les substances avant de les autoriser dans le cadre d'une politique visant à améliorer la santé humaine. Cela passe par le contrôle des applications des sels métalliques tels que le sulfate de nickel ; utilisé dans les revêtements de zinc-nickel. Pour pallier ces contraintes, de nouvelles pistes ont déjà été explorées à l'occasion du projet IZAC : Inovative Zinc Al loy Coating. Ce projet, un consortium entre le laboratoire UTINAM et des partenaires industriels, a contribué à l'élaboration d'une couche sacrificielle ZnFe à haute teneur en Fer objet d'un brevet international. Le présent travail fait partie du projet ATLAS, piloté par L'IRT M2P en regroupant trois universités, françaises et belges avec un consortium de 22 partenaires industriels. La contribution académique de la thèse faite dans UTINAM est la compréhension du comportement électrochimique des électrolytes en discriminant l'influence de chacun des constituants, distinguant les fonctions (complexants, additifs de chimisorption, sels supports) des interactions (complexation et précipitation). Le comportement dynamique des systèmes sera également observé par l'étude des transitoires lors de la modulation de la polarisation de l'onde de courant. Il s'agira de chercher les séquences les plus efficaces vis-à-vis de l'électrodéposition et de la teneur en éléments d'alliage, en pulse simp les et inverses. Une attention particulière sera donnée aux phénomènes microscopiques, et en particulier aux premiers instants des dépôts car l'étape de germination est répétée à chaque pulse de courant, grâce à des chronoampérométries à grande vitesse d'acquisition. Une modélisation du comportement de la couche limite sera recherchée sur la base des équations de diffusion avec le solveur COMSOL. Dans un second volet de la thèse, on s'intéressera aux propriétés physico-chimiques et fonctionnelles des revêtements obtenus pour les différentes conditions. En particulier, les effets des courants pulsés sur la composition des dépôts, la distribution des éléments d'alliage et la répartition des épaisseurs seront quantifiés. La modélisation sera un outil important utilisé en parallèle des courants pulsés afin de réussir à obtenir une meilleure répartition des lignes de courants sur des géométries simples et complexes. L'objectif est d'agir sur la bonne répartition des dépôts, sur la surf ace des pièces plane, mais aussi des accidents (rainures, trous, trous borgnes, coudes...) grâce à une meilleure compréhension du fonctionnement de l'électrolyte et des effets des courants pulsés. Les dépôts réalisés avec les meilleurs paramètres de séquences de pulses (Ja, Jc, Ta, Tc…) seront ensuite caractérisés, notamment par microscopie à balayage (MEB) ou par diffraction des rayons X (DRX), ainsi que par des caractérisations fonctionnelles par des tests internes au laboratoire, mais aussi chez les partenaires industriels du projet. En vue du passage à des volumes de travail plus important à l'IRTM2P, une étude des paramètres à prendre en compte sera réalisée en unité pilote à l'Institut UTINAMThe development of new corrosion resistant plating has become a challenge in both environmental and economic terms. Indeed, numerous constraints have aroused in surface treatments domain in recent decades, most of them due to the restriction on the use of certain products. As for example, RoHS Directive (Restriction of the Use of Certain Hazardous Substances) limits the use of dangerous substances in electrical and electronic equipment. In the same manner, REACH European regulations realized the substances inventory before their authorization, for the improvement of environmental conditions and human health. This include the control of metal salts as for example nickel sulphates, used in several applications such as zinc-nickel coatings. To overcome these constraints, new solutions have already been explored during the IZAC project: Innovative Zinc Alloys Coating. This project, a consortium between the UTINAM laboratory an d industrial partners, has contributed to the development of a ZnFe sacrificial layer with high iron content, subject to an international patent. The present work is part of the ATLAS project, led by the IRT M2P, which gather together three French and Belgian Universities associated to a consortium of 22 industrials partners. The academic contribution of the present thesis made in the UTINAM institute is the understanding of the electrochemical behavior of the electrolyte by discriminating the influence of every constituents. The different functions (complexing agents, chemisorption additives, supports salts…) will be insulated from the interactions (complexation and precipitation). The dynamic behavior of the systems will also be observed by the study of the transients during the modulation of the polarized current wave. The final goal will end up with the most effective sequences regarding the electrodeposition ability and the content of alloys elements, with simple and inverse pu lses. Special attention will be paid to microscopic phenomena and to the first moments of the plating, since the germination step is repeated for each current pulse, by high speed chronoamperometry. A modeling of the behavior of the boundary layer will be proposed by using the diffusion equation with COMSOL solver. In a second part of the thesis, physicochemical and functional properties of the plating obtained for different conditions will be investigated. For this purpose, effects of pulsed currents on the coatings composition, alloying elements distribution and thickness distribution will be quantified. Modelling will be used together with pulsed currents to obtain a better repartition of current lines on simple and complexes geometries. The objective is to act for an optimum repartition of the coatings on the surfaces of flat parts, but also on accidents (grooves, holes, blind holes, elbows…) thanks to a better understanding of the interactions between the electrolyte and the p ulsed currents. The coatings elaborate with the best pulse sequence parameters (Ja, Jc, Ta, Tc…) will be characterized by several techniques among with scanning microscopy (SEM) or X-ray diffraction (XRD) as well as for their functional behavior, by internal laboratory tests and with industrial partners means. Finally, to apprehend the scale-up to greater volumes at IRTM2P, a study of the parameters in a pilot unit at the UTINAM Institute will be undertaken
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Bacaicoa, Inigo [Verfasser]. "Effect of heat treatment and iron content on the microstructure and mechanical properties of a secondary Al-Si-Cu alloy / Inigo Bacaicoa." Kassel : Universitätsbibliothek Kassel, 2019. http://d-nb.info/1195721846/34.
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FALERO, EDELINK EFRAIN TINOCO. "DEVELOPMENT OF A TECHNIQUE TO PERMIT THE USE OF IRON ORES BEARING HIGH PHOSPHOR CONTENT AIMING AT COMPETITIVENESS FOR THE DIRECT REDUCTION MARKET." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2011. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19251@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORPROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
As pelotas de minério de ferro têm suas propriedades fortemente dependentes da natureza das fases escorificadas que se formam durante o processo de queima. Neste trabalho são apresentados os resultados de uma das pesquisas que compõem o projeto cooperativo entre a Samarco e o Grupo de Siderurgia do DEMa / PUC-Rio, envolvendo a possibilidade de utilização de minérios de ferro portadores de fósforo (pellet feed), na produção de pelotas para redução direta. Com este objetivo foram geradas amostras de escórias sintéticas de mesma composição que as das pelotas RD comerciais, as quais foram submetidas a condições experimentais análogas as do processo industrial. Inicialmente a ciclos térmicos em forno tipo pot-grate e, posteriormente, em escala laboratorial, usando forno de mufla, seguido de etapas de resfriamento em velocidades distintas. Foi possível então constatar que velocidades mais altas de resfriamento, aplicadas na etapa final dos ciclos térmicos, produziam escórias sintéticas sensivelmente amorfas, o que levou a conclusão que as fases escorificadas das pelotas RD também se apresentariam como estruturas não cristalinas. Finalmente, por meio de teste especificamente desenvolvido para a análise seletiva de fósforo em fases oxídicas, conseguiu-se obter uma maior eficiencia na mensuração deste elemento quando dissolvido em escórias amorfas, o que viabilizou a medida das quantidades de fósforo que efetivamente migraram para as mesmas, quando se submetiam as amostras de pellet feed a diferentes temperaturas, variados tempos de residencia e distintas basicidades. Por fim, foi possivel concluir ser o incremento de basicidade do pellet feed um fator de significativa melhoria para o transporte e a dissolução do fósforo pelas escórias, em particular quando submetidos a temperaturas superiores a 900 graus Celsius.
Iron ore pellets have their properties strongly dependent on the nature of the phases present in the slags formed during pelletization. In this work are presented the first results of a research program involving the utilization of phosphorous bearing iron ores in the production of DR pellets (Direct Reduction pellets). Aiming at this, synthetic slags, produced with same composition of the gangue of a commercial DR pellet, were submitted to operational conditions similar to those of the industrial pelletizing process, but performed in a pot-grate reactor and in a laboratory furnace. The obtained slags samples were cooled at different rates, permitting to observe that at high cooling rates the slags obtained were amorphous, suggesting the occurrence of a similar amorphous structure for the slags present in the DR pellets. Finally, tests developed for a selective analysis of phosphorous in oxide phases, showed better efficiency when applied to amorphous slags than in crystalline ones. Further, the behavior of the phosphor dissolution in the obtained slags during the heating of pellet feed samples was evaluated. In this phase different temperatures, resident times and basicities were tested using a laboratory furnace. The results indicated improvements in the phosphor dissolution with the basicity increase when temperatures above 900 Celsius degrees were applied.
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Webber, J. Beau W., Philip Bland, John H. Strange, Ross Anderson, and Bahman Tohidi. "Why you can’t use water to make cryoporometric measurements of the pore size distributions in meteorites – or in high iron content clays, rocks or concrete." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-191847.
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Many porous materials have high susceptibility magnetic gradients in the pores, due to the presence of iron or other magnetic materials. Thus if probe liquids are placed in the pores they exhibit fast decaying signals with a short T2*. Usually the actual T2 of the liquids is also reduced, due the presence of paramagnetic ions in the pore walls.
The usual solution in NMR is to measure an echo (or echo train) at short times. However, recent work [J. Phys.: Condens. Matter 19, 415117, 2007.] has shown that water/ice systems near a pore wall form rotator phase plastic ice, with T2 relaxation times in the region of 100 to 200 ms. Thus if a NMR cryoporometric measurement is attempted with a measurement time significantly less than 1 or 2 milli-seconds, the result is to make a measurement based on the phase properties of the brittle to plastic ice phase transition, not that of the brittle ice to water phase transition. This gives rise to artefacts of small pore sizes that may not actually be present. This work successfully uses a-polar liquids instead.
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Webber, J. Beau W., Philip Bland, John H. Strange, Ross Anderson, and Bahman Tohidi. "Why you can’t use water to make cryoporometric measurements of the pore size distributions in meteorites – or in high iron content clays, rocks or concrete." Diffusion fundamentals 10 (2009) 3, S. 1-3, 2009. https://ul.qucosa.de/id/qucosa%3A14092.
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Many porous materials have high susceptibility magnetic gradients in the pores, due to the presence of iron or other magnetic materials. Thus if probe liquids are placed in the pores they exhibit fast decaying signals with a short T2*. Usually the actual T2 of the liquids is also reduced, due the presence of paramagnetic ions in the pore walls.
The usual solution in NMR is to measure an echo (or echo train) at short times. However, recent work [J. Phys.: Condens. Matter 19, 415117, 2007.] has shown that water/ice systems near a pore wall form rotator phase plastic ice, with T2 relaxation times in the region of 100 to 200 ms. Thus if a NMR cryoporometric measurement is attempted with a measurement time significantly less than 1 or 2 milli-seconds, the result is to make a measurement based on the phase properties of the brittle to plastic ice phase transition, not that of the brittle ice to water phase transition. This gives rise to artefacts of small pore sizes that may not actually be present. This work successfully uses a-polar liquids instead.
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Finer, Julia E. "Evaluation of the Effect of Dioxygen, Industrial Heterogeneous Palladium Catalyst, pH and Iron Content on the Generation of 3 High-Value Aldehydes from Corn Stover Lignin." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397234827.
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Mäkinen, Katri. "Optimisation of local material parameters : Optimising local material parameters in ductile cast iron cylinder head casting." Thesis, Jönköping University, JTH, Material och tillverkning, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54500.
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The constantly tightening emission regulations demand the engines to be moreefficient, to get more power out of smaller engines. Higher engine loads andcomponent temperatures are causing more stresses to engine components. Therefore,a company that produces engines wanted to study if it would be possible to increasethe capabilities of the components by optimising the used material. In this final project work, a cylinder head will be studied. The cylinder heads for theengines are made of ductile cast iron. The limits of that material are near safety limits,and therefore a better material is needed. In this work are some previous studiesanalysed and tried to find how to optimise the used material. The optimised materialshould have better thermal conductivity properties combined with sufficient strengthproperties. Previous studies were analysed to gather knowledge of the elements that affect thematerial parameters. Those studies showed that copper, silicon, pearlite fraction, andthe use of chills are the elements to be optimised. Silicon and pearlite fraction waschosen as optimisation parameters because of their effect on the thermal conductivityand strength properties. Copper was chosen as an optimisation variable due to its effecton the pearlite formation. Chills were used to affect the cooling rate and thereby thepearlite formation. The work was made using MAGMASOFT™ simulation software to simulate cylinderhead casting. The simulated cylinder head was divided into 4 parts for the simulations.For those sections were then set targets for pearlite fraction according to previousstudies. The silicon content was kept constant in the simulation, based on the studiespresented in this work. Copper content was simulated with variations from 0 to 0.7weight-%, and chill heights were simulated from 20 to 60 mm and without chills. After simulating the different variables, the results were analysed. Then the selectedcasting simulation result was mapped to finite element simulation mesh to include thelocal material parameters to finite element simulation. With the finite elementsimulation, the estimated lifetime of the component was simulated. By analysing the casting simulation results, an optimal combination was found. Theoptimal material parameters for a cylinder head casting would be copper 0.5weight-%, silicon 1.9 weight-% and chills thicker than 40 mm on the flame plate. Theoptimised material gives more possibilities to develop engines even further when thecomponent demands are growing.
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Jeftić, Jelena. "The influence of pressure on the thermal equilibrium and the relaxation dynamics in the iron(II) spin-crossover systems : [Zn1-xFex(ptz)6](BF4)2 and [Fe(ptz)6](PF6)2, (x = 0.1, 0.32 and 1, ptz = 1-n-propyltetrazole) /." [S.l.] : [s.n.], 1997. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Snyder, William E. "Construction of a hybrid vector which allows for regulation of expression of cloned genes in anacystis nidulans R2 by controlling the iron content of the growth medium." Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/560278.
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A hybrid vector, pANIC1, was to be constructed which was capable of regulating expression of cloned genes in both Escherichia coli and Anacystis nidulans R2 by controlling the iron content of the growth medium. Plasmid pANIC1 would have origins of replication for E. coli and A. nidulans R2, and a marker gene conferring ampicillin resistance. It would also contain the promoter for the irpA gene which is active only in low iron growth conditions.The first two stages of the construction were successfully completed, but unfortunately the final construction proved to be unstable. Recent information has shown that operator sequences upstream from the irpA gene's promoter result in an unstable message. This may be interfering with the normal functioning of the host cell, resulting in an unstable construction. In future experiments it may be neccessary to alter the growth conditions or remove the upstream sequences in order to stablize the construction.Department of Biology
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Цюра, Надія Ярославівна. "Сумісний процес фільтрування та сушіння дисперсних матеріалів." Diss., Національний університет "Львівська політехніка", 2021. https://ena.lpnu.ua/handle/ntb/56692.
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Дисертаційна робота присвячена теоретичним та експериментальним дослідженням фільтраційного сушіння дисперсних матеріалів, зокрема Fe(II) сульфат гептагідрату, відпрацьованого деревного
борошна й залізоокисного пігменту з метою проектування енергоощадного обладнання. Встановлені основні фізико-механічні характеристики стаціонарного шару досліджуваних матеріалів, а саме: насипна густина, пористість, питома поверхня, еквівалентний діаметр каналів, крізь якіфільтрується тепловий агент, усереднений діаметр частинок. На основі узагальнення результатів досліджень гідродинаміки запропоновані рівняння для встановлення гідравлічного опору стаціонарного шару за різних параметрів теплового агенту, які можуть бути використані на етапі проектування нового сушильного обладнання.
Експериментальним шляхом досліджений теплообмін під час фільтраційного сушіння й запропоновані критеріальні залежності у вигляді безрозмірних комплексів для визначення коефіцієнтів тепловіддачі від
теплового агенту до шару Fe(II) сульфат гептагідрату. Встановлений характер впливу висоти стаціонарного шару Fe (II) сульфат гептагідрату, відпрацьованого деревного борошна й залізоокисного пігменту, а також температури теплового агенту й швидкості фільтрування на інтенсивність
фільтраційного сушіння та запропоновані розрахункові залежності для прогнозування процесу висушування вказаних матеріалів в періодах повного та часткового насичення теплового агенту вологою.
Розроблена схема сушильної установки для зневоднення дисперсних матеріалів в стаціонарному шарі шляхом профільтровування теплового агенту крізь пористу структуру, на яку отриманий патент України на винахід. Наведена методика розрахунку та проведені технологічні обчислення, які дали змогу розрахувати основні розміри сушарки та встановити параметри процесу фільтраційного сушіння. The work deals with the filtration method for drying Fe (II) sulfate of heptahydrate, the exhausted wood flour and iron oxide pigment. This method is elected as the most effective according to the critical analysis of literature data. The work is dedicated to the theoretical and experimental researches of filtration drying of dispersed materials, in particular Fe (II) sulfate of heptahydrate, the exhausted wood flour and iron oxide pigment for the purpose of designing of the energy saving equipment. The basic physical and mechanical characteristics of
the stationary layer of the studied materials are determined, such as: bulk density, porosity, specific surface area, averaging of particles size, equivalent diameter of the channels through which the heat agent is filtered. On the basis of obtained experimental data of hydrodynamics research, the equations for establishing the
hydraulic resistance of the stationary layer at variable parameters of the heat agent are proposed. Heat transfer during filtration drying is investigated experimentally and criterion dependences in the form of dimensionless complexes for determination of heat transfer coefficients from heat agent to Fe (II) sulfate heptahydrate layer are proposed. The nature of the influence of the height of the stationary layer of Fe (II) sulfate heptahydrate, exhausted wood flour and iron oxide pigment, as well as the temperature of the heat agent and filtration rate on
the intensity of filtration drying and the proposed dependences for predicting the drying process of these materials. The basic scheme of the drying installation for dehydration of dispersed materials, a technique of its calculation are developed and the basic technological calculations are carried out. The patent of Ukraine for
the invention has protected the plant.
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Rentel, Raimund. "Development and implementation of a flow injection analyser with chemiluminescence for detection of sub-nanomolar Fe in seawater." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95832.
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Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Iron is an essential micronutrient for all phytoplankton and is found in seawater at picomolar-level concentrations. For the first time in South Africa, a technique that utilizes a flow injection analyser (FIA) coupled with a chemiluminescence reaction has been developed for the analysis of Fe in seawater samples. The developed method is an improvement on similar available methods and uses commercially available resin (IDA) as opposed to the one that requires synthesis in the laboratory. Furthermore, the method requires reduced reagent concentrations thereby providing better results in a cost-efficient and easy manner. The improvements resulted in better precision while eliminating the loss of resin through bleeding, a common problem when using 8-HQ resin as per prior methods. Method validation was performed using internationally calibrated reference material provided by GEOTRACES and the values obtained were within the error limits of certified range. An inter-laboratory calibration was also conducted as part of the verification of the system. Surface samples from the SANAE 51 cruise were analysed for dFe and TdFe. Subsequently, the method was implemented on the SANAE 53 voyage on board the SA Agulhas II, to assess trace metal sampling protocol for any contamination issues, as well as for the analyses of collected samples. Current results suggest some contamination during collection stages, but this is still to be verified by complementary data on macronutrients and chlorophyll. The method was successfully developed and implemented in a land based clean laboratory, as well as on board a vessel.
AFRIKAANSE OPSOMMING: Yster is „n noodsaaklike mikrovoedsel vir fitoplankton en word in seewater in pikomolêre konsentrasies gevind. Hierdie lae konsentrasies en potensiële besoedeling gedurende monsteropname vanaf „n skip se platform maak akkurate Fe-analise moeilik. Vir die eerste keer in Suid-Afrika is „n tegniek ontwikkel wat gebruik maak van „n vloei- inspuitinganaliseerder (VIA), met „n geassosieerde chemiluminessensiereaksie, om die analise van Fe in seewatermonsters uit te voer. In teenstelling met soortgelyke bestaande metodes wat labratorium-gesintetiseerde hars vereis, is die nuut-ontwikkelde metode „n verbetering wat gebruik maak van „n kommersieel-beskikbare hars (IDA). Verder vereis die metode verminderde reagenskonsentrasies wat sodoende beter resultate lewer op 'n koste-effektiewe en eenvoudiger wyse. Die verbeteringe het gelei tot verhoogde akkuraatheid en uitskakeling van die verlies van hars deur dreinering – „n algemene probleem wat ondervind is met die gebruik van 8-HQ hars in vorige metodes. Geldigheidsbepaling van die metode is met internasionaal-gekalibreerde verwysingsmateriaal, verskaf deur GEOTRACES, uitgevoer. Die waardes wat verkry is, was binne die foutgrense van die gesertifiseerde skaal. „n Interlaboratorium-kalibrasie is ook uitgevoer as deel van die verifikasie van die stelsel. Daarna is die metode geïmplementeer gedurende die SANAE 53 reis op die SA Agulhas II, om die spoormetaal-monsternemingprotokol vir enige besoedelingskwessies te evalueer, asook vir die ontleding van versamelde monsters. Huidige resultate dui op „n mate van besoedeling tydens die versamelingstadiums, maar dit moet nog geverifieer word deur aanvullende data van die totale oplosbare Fe, makrovoedingstowwe en chlorofil.
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MÖRÉE, GUSTAV. "Experimental Comparison of Losses in a Grid-connected and M2C-fed 11kW Induction Motor." Thesis, KTH, Elektrisk energiomvandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160705.
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This thesis analyzes the power losses in induction machines and how the losses depend on the harmonic content of the applied voltages. Two cases are compared, one case where a machine is fed with a sinusoidial voltage and one case with a modular multilevel converter (M2C). The sine is representing an ideal grid while the M2C represents a case with harmonic content. The usage of converters for electrical drive systems is increasing due to advantages when the rotor speed could be variable by changing the frequency of the voltage. This is usually increasing the efficiency of the overall system, but is also adding harmonics fed to the machine and switching losses in the converter. Low switching losses in the inverter usually create higher harmonic content that instead increases the losses of the machine. The M2C is then proposed as a converter topology that can keep the harmonic content low while keeping the switching losses relatively low. This study focuses on the iron losses, the part of the total losses that is most hard to predict or measure. Today’s methods used to calculate the iron losses are often rough approximations that do not take the impact of the harmonic content of voltage into consideration, even though the iron losses are dependent on the harmonics. Experimental results in the study show that the losses of a M2C-fed case do not differ much from a sine-fed case. The difference could be explained by low increase of iron losses caused by the small harmonic content from the M2C. The increase of iron losses was linked to the harmonic content of the voltage.Detta examensarbete analyserar effektförluster i induktionsmaskiner och hur förlusterna beror på övertonsinnehållet i den matande spänningen. Två fall kommer att jämföras, ett fall där en maskin är matad från en sinus spänning och ett fall med en modulär multinivå omvandlare (M2C). Sinusen representerar ett idealt nät medan M2C representerar ett fall med övertonsinnehåll. Användning av omvandlare för elekriska drivsystem ökar på grund av fördelarna när rotorhastighet kan varieras genom att ändra frekvensen från den matande växelriktaren. Detta ökar vanligtvis verkningsgraden på det sammanlagda systemet, men detta bidrar även med övertonsinnehåll matat till maskinen och switchförluster i omvandlaren. Låga switchförluster i omvandlaren medför oftast ett högt övertonsinnehåll som istället ökar förlusterna i maskinen. M2C är därför föreslaget som en teknik som håller övertonsinnehållet lågt medan switchförlusterna är relativt låga. Denna studie fokuserar på järnförluster, den del av de totala förlusterna som är som svårast att förutse eller mäta. De metoder som finns för att beräkna järnförlusterna är vanligtvis grova skattningar som inte tar hänsyn till inverkan från spänningens övertoninnehåll, även om järnförluster beror på övertonerna i stor utsträckning. Experimentella resultat i studien visar att förlusterna i ett M2C-matat fall inte avviker i stor utsträkning jämte ett sinusmatat fall. Skillnanen kan förklaras utifrån den lilla ökningen av järnförluster från det låga övertonsinnehållet från M2C:n. Järnförlusterna ses vara kopplade till övertonsinnehållet i spänningen.
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Weissfloch, Phillip. "Iron-GaAs schottky contact for mesfet applications." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61798.
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Collin, Angelica, and Matilda Hammarberg. "Röstfaktorer som avslöjar ironi : Akustiska likheter och skillnader mellan sinnesstämningar." Thesis, Linköpings universitet, Institutionen för klinisk och experimentell medicin, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-106209.
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Ordet ironi definieras som ett yttrande där "betydelsen är motsatsen till orden". Denna rapport är en fortsatt studie på Peder Palmérs studie Vad är ironiskt tal: att hitta de auditiva ledtrådarna (2013). Materialet som ligger till grund för denna uppföljande studie består av inspelningar av tre olika talare med fem olika meningar i fem olika sinnesstämningar; glädje, ilska, allvar, ironi och sarkasm. Trettio män och kvinnor i åldern 18-60 år har lyssnat på dessa meningar och kategoriserat dem utifrån tolkad sinnesstämning. Till detta användes avsedd blankett. Författarna har uppmätt grundton och intensitet som har jämförts mellan de olika sinnesstämningarna. Grundton har också jämförts mellan de tre talarna. Dessa jämförelser ligger till grund för en analys som kan ge information om betydelsen av dessa akustiska parametrar, liksom andra faktorer såsom kontext, vid identifiering av olika stämningar. Syftet är att undersöka om de sinnesstämningar som testpersonerna oftast förväxlar är mest lika ur ett akustiskt perspektiv, och att hitta ett eventuellt samband mellan grundton, intensitet och testpersonernas perceptuella tolkning. Det insamlade materialet analyserades utifrån aktuella frågeställningar. Studiens resultat påvisar att det är svårt att enbart utifrån akustiska parametrar tolka sinnesstämning. Grundtonsfrekvens och intensitet förefaller ha en viss betydelse när det kommer till förväxlingar mellan ironi och andra sinnesstämningar. Inga skillnader påvisas mellan mäns och kvinnors förmåga att identifiera ironi och sarkasm enbart utifrån akustiska parametrar.The word irony is defined as an utterance where the meaning is the opposite of the words. This report is a continuing study of Peder Palmér's study What is ironic speech: to find the auditory clues (2013). The basis for this follow-up study consists of recordings with three different talkers with five sentences in five different moods: happiness, anger, seriousness, irony and sarcasm. Thirty men and women aged 18 to 60 years have been listening to the sentences and categorized them based on interpreted mood. The authors have measured fundamental frequency and intensity, and used these measurements as a basis to elucidate the perception of irony and the ability to perceive mood based on changes in fundamental frequency and intensity. The fundamental frequency has also been compared between the three talkers. An acoustic comparison between the different moods forms the basis for the analysis, which can provide information about the importance of acoustic parameters, as well as other factors such as context, when identifying different moods. The aim is to examine whether the moods that are most similar from an acoustic perspective are the ones that the test subjects most often fail to distinguish. The results show that it is difficult to solely from acoustic parameters interpret mood. Fundamental frequency and intensity appear to be of some importance when confusing irony with other moods. No differences were found between men and women's ability to detect irony and sarcasm based solely on acoustic parameters.
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Haselgrove, Colin. "Iron Age coin finds in South-East England : the archaeological context." Thesis, University of Cambridge, 1986. https://www.repository.cam.ac.uk/handle/1810/273112.
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Brachmann, Steffi. "Wertigkeit ausgewählter Eisenstoffwechselparameter im Ausdauersport." Doctoral thesis, Humboldt-Universität zu Berlin, Philosophische Fakultät IV, 2011. http://dx.doi.org/10.18452/16304.
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Einleitung: Eisenmangel ist ein häufiges Problem bei Ausdauersportlern, da dieser die Leistungsfähigkeit einschränken und zu einer Blutanämie führen kann. Von den klassischen Eisenstoffwechselparametern sind nur wenige geeignet, den tatsächlichen Eisenstatus anzuzeigen, da sie durch sportliche Aktivität per se beeinflusst werden können. In der Studie wird die Wertigkeit moderner Eisenstoffwechselparameter im Ausdauersport untersucht. Ergebnisse und Diskussion: Der Hämoglobingehalt der Retikulozyten (CHr) und der prozentuale Anteil der hypochromen Erythrozyten (% HYPO) bleiben als moderne Parameter der Eisenstoffwechseldiagnostik auch nach regenerativen, extensiven sowie intensiven Ausdauerbelastungen konstant. Sie zeigen somit unbeeinflusst von der (Ausdauer-)Sportart als auch von der Belastungsdauer und –intensität die aktuelle Eisenversorgung der Erythropoese im Knochenmark an. Als Monitoringparameter im Rahmen einer Eisensubstitution sind der CHr sowie der prozentuale Anteil hypochromer Retikulozyten sensible Parameter, mit denen sich schnell und zuverlässig die Effektivität einer oralen Eisensubstitution nachweisen lässt. Der Eisenstatus kann durch die alleinige Bestimmung des CHr bzw. des % HYPO nicht exakt ermittelt werden. Im Gegensatz zum Einsatz bei klinischen Fragestellungen können sie zu diesem Zeitpunkt in der Sportmedizin allenfalls nur ein ergänzender Parameter in der Differentialdiagnostik eines Eisenmangels sein. Die für Ausdauersportler ermittelten Referenzwerte liegen bei 28,8-35,9 pg für den CHr und bei 0-0,5 % für die hypochromen Erythrozyten. Ein belastungsbedingter Anstieg des Eisen-regulierenden Hormons Hepcidin könnte auf Grund seiner inhibitorischen Wirkung auf die intestinale Eisenabsorption sowie auf die Freisetzung von Eisen aus den Makrophagen zur Entwicklung von Eisenmangel-zuständen führen. Die Entwicklung von Hepcidin-Antagonisten könnte in Zukunft therapeutische Anwendungen finden.Introduction: Athletes are commonly diagnosed with iron deficiency, particularly those involved in endurance sports. It often not only decreases athletic performance but also contributes to the development of anaemia. Many biochemical markers are used to evaluate body iron stores but some of them are affected by physical exercises. This study was designed to investigate new haematological parameters in endurance athletes. Results and discussion: Reticulocyte hemoglobin content (CHr) and percentage of hypochromic red cells (% HYPO) were highly stable in athletes subjected to varying physical loads. Furthermore, they were neither affected by different forms of endurance sports nor by their duration and intensity. These modern indices are able to reflect the availability of iron during erythropoiesis at all times. In the early prediction of response to oral iron supplementation, the reticulocyte indices CHr and % HYPOr (percentage of hypochromic reticulocytes) are the most sensitive parameters. However, it is not possible to assess the iron status in athletes by CHr and % HYPO alone. In contrast to other clinical cases they can only be an additional parameter in the differential diagnosis of iron deficiency. The calculated reference range for endurance athletes are 28,8 - 35,9 pg for CHr and 0-0,5 % for % HYPO. As the iron-regulating hormone hepcidin is inhibiting the absorption of iron from the diet at the site of the duodenal enterocytes and blocking the release of iron from macrophages that have collected senescent erythrocytes, an exercise induced up-regulation of hepcidin activity might potentially be a new mechanism causing iron deficiency in athletes. Therefore, the development of hepcidin antagonists could prove to be helpful with regard to therapeutic utilization.
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Sousa, Daniel Vieira de. "Alterações eletroquímicas e sua relação com a produção de gás metano em solos alagados por barragens." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/5542.
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Previous issue date: 2011-05-30Fundação de Amparo a Pesquisa do Estado de Minas Gerais
The emission of gases of the greenhouse effect has increased dramatically since the geological era until the present days. Currently the use of fossil fuels and the changing of the use of the Earth are most responsible for the emission of these gases to the atmosphere.The carbon in the soil represents more than three times the carbon in the terrestrial biomass and about two times the carbon in the atmosphere, been a potential source of CO2 and CH4.The biogeochemical process that occurs in the soil or sediments for the emission of gases such as carbon dioxide and methane are controlled by process like the reduction of mineral compounds mainly oxides and amorphous and poor crystalline in anaerobic environment. These process leads to the formation of a favorable habitat suitable to the population grows of Methanogenic bacteria consequently with the production of gases of greenhouse effective. Nowadays there are several projects that defend that the hydroelectric dam offers a great contribution to the emission of the effective of greenhouse gases. This project has the purpose of study what the characteristics has more influence for the production of the emission of greenhouse effective in flood soils in hydroelectric lakes. The chapter one is dedicated to literature review where are addressed the more relevant topics. The chapter II had the purpose of studying the electrochemical dynamics of the soil at Zona da Mata mineira subject to flood due to the construction of hydroelectric. As a result we obtained that how bigger is the of Fe, bigger will be reduction of the soil, which lead us to establish the habitats proper for the establishment of the growth of Methanogenic bacteria‟s. population. The contents of Fe, CO and N have more influence in the ox reduction of flood soil. The chapter III had the purpose of studying dynamics and reactivity of the soil organic carbon (SOC) such as it is also dedicated to estimate the production of CH4 in soils flooded by hydroelectric dams lake with the purpose of identifying which characteristics has more influence in the production of methane comes from an eventually flooded of soils. As a result were obtained that the reactivity of SOC receives influence of the texture of the soil, and the finer is the texture greater is the presence of free fractions. The N shows an important factor to be analyzed due to its relation with the degradation of organic compound and microbial activity.
As emissões de gases do efeito estufa (GEE) têm aumentado vertiginosamente desde eras geológicos até os dias atuais. Atualmente a utilização de combustíveis fósseis, e alterações no uso da Terra, são as maiores responsáveis pelas grandes emissões destes gases para a atmosfera. O carbono contido no solo representa mais de três vezes o carbono contido em toda a biomassa terrestre e cerca de duas vezes o carbono contido na atmosfera, sendo, dessa forma, uma potencial fonte emissora de CO2 e CH4. Os processos biogeoquímicos que ocorrem em solos e ou sedimentos para emissão de gases como o dióxido de carbono e metano, são controlados por processos como a redução de compostos minerais, principalmente óxidos, amorfos e mal cristalizados em ambientes anaeróbios. Estes processos levam a formação de um habitat propício para o crescimento populacional de bactérias metanogênicas, com a conseqüente produção de gases do efeito estufa. Atualmente há diversos trabalhos que defendem que barragem de usinas hidroelétricas oferece uma grande contribuição na emissão de gases do efeito estufa. Nesta pesquisa objetivou-se estudar quais as características do exercem mais influencia para a produção de gases do efeito estufa em solos alagados em lagos de hidroelétricas. O capítulo I é dedicado a revisão de literatura, onde são abordados temas que se julgam relevantes. No capítulo II se objetivou estudar a dinâmica eletroquímica de solos da zona da mata mineira passíveis de serem submetidos a alagamento devido a construção de hidroelétricas. Como resultado obteve-se que quanto maior for a atividade de Fe, maior será o potencial de redução do solo, o que leva ao estabelecimento de habitats, apropriados para o estabelecimento de populações de bactérias metanogênicas. Os teores de Fe, CO e N, são os que mais exercem influencia no processo de oxiredução de solos alagados. O capítulo III teve por objetivo estudar dinâmica e reatividade do carbono orgânico do solo (COS), bem como dedicado a estimar a produção de CH4 em solos alagados por lagos de usinas hidroelétricas, com o intuito de identificar quais características exerce mais influência na produção de metano, provinda do eventual alagamento dos solos. Como resultados foram obtidos que a reatividade do COS recebe influencia da textura do solo, sendo que quanto mais fina a textura maior a presença de frações livres. O N total se mostra um importante fator a ser analisado devido sua relação com a degradação de compostos orgânicos e atividade microbiana.
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Hernández, Farias Delia Irazu. "Irony and Sarcasm Detection in Twitter: The Role of Affective Content." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90544.
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Social media platforms, like Twitter, offer a face-saving ability that allows users to express themselves employing figurative language devices such as irony to achieve different communication purposes. Dealing with such kind of content represents a big challenge for computational linguistics. Irony is closely associated with the indirect expression of feelings, emotions and evaluations. Interest in detecting the presence of irony in social media texts has grown significantly in the recent years.
In this thesis, we introduce the problem of detecting irony in social media under a computational linguistics perspective. We propose to address this task by focusing, in particular, on the role of affective information for detecting the presence of such figurative language device.
Attempting to take advantage of the subjective intrinsic value enclosed in ironic expressions, we present a novel model, called emotIDM, for detecting irony relying on a wide range of affective features. For characterising an ironic utterance, we used an extensive set of resources covering different facets of affect from sentiment to finer-grained emotions. Results show that emotIDM has a competitive performance across the experiments carried out, validating the effectiveness of the proposed approach.
Another objective of the thesis is to investigate the differences among tweets labeled with #irony and #sarcasm. Our aim is to contribute to the less investigated topic in computational linguistics on the separation between irony and sarcasm in social media, again, with a special focus on affective features. We also studied a less explored hashtag: #not. We find data-driven arguments on the differences among tweets containing these hashtags, suggesting that the above mentioned hashtags are used to refer different figurative language devices.
We identify promising features based on affect-related phenomena for discriminating among different kinds of figurative language devices. We also analyse the role of polarity reversal in tweets containing ironic hashtags, observing that the impact of such phenomenon varies.
In the case of tweets labeled with #sarcasm often there is a full reversal, whereas in the case of those tagged with #irony there is an attenuation of the polarity.
We analyse the impact of irony and sarcasm on sentiment analysis, observing a drop in the performance of NLP systems developed for this task when irony is present. Therefore, we explored the possible use of our findings in irony detection for the development of an irony-aware sentiment analysis system, assuming that the identification of ironic content could help to improve the correct identification of sentiment polarity. To this aim, we incorporated emotIDM into a pipeline for determining the polarity of a given Twitter message.
We compared our results with the state of the art determined by the "Semeval-2015 Task 11" shared task, demonstrating the relevance of considering affective information together with features alerting on the presence of irony for performing sentiment analysis of figurative language for this kind of social media texts. To summarize, we demonstrated the usefulness of exploiting different facets of affective information for dealing with the presence of irony in Twitter.Las plataformas de redes sociales, como Twitter, ofrecen a los usuarios la posibilidad de expresarse de forma libre y espontanea haciendo uso de diferentes recursos lingüísticos como la ironía para lograr diferentes propósitos de comunicación. Manejar ese tipo de contenido representa un gran reto para la lingüística computacional. La ironía está estrechamente vinculada con la expresión indirecta de sentimientos, emociones y evaluaciones. El interés en detectar la presencia de ironía en textos de redes sociales ha aumentado significativamente en los últimos años. En esta tesis, introducimos el problema de detección de ironía en redes sociales desde una perspectiva de la lingüística computacional. Proponemos abordar dicha tarea enfocándonos, particularmente, en el rol de información relativa al afecto y las emociones para detectar la presencia de dicho recurso lingüístico. Con la intención de aprovechar el valor intrínseco de subjetividad contenido en las expresiones irónicas, presentamos un modelo para detectar la presencia de ironía denominado emotIDM, el cual está basado en una amplia variedad de rasgos afectivos. Para caracterizar instancias irónicas, utilizamos un amplio conjunto de recursos que cubren diferentes ámbitos afectivos: desde sentimientos (positivos o negativos) hasta emociones específicas definidas con una granularidad fina. Los resultados obtenidos muestran que emotIDM tiene un desempeño competitivo en los experimentos realizados, validando la efectividad del enfoque propuesto. Otro objetivo de la tesis es investigar las diferencias entre tweets etiquetados con #irony y #sarcasm. Nuestra finalidad es contribuir a un tema menos investigado en lingüística computacional: la separación entre el uso de ironía y sarcasmo en redes sociales, con especial énfasis en rasgos afectivos. Además, estudiamos un hashtag que ha sido menos analizado: #not. Nuestros resultados parecen evidenciar que existen diferencias entre los tweets que contienen dichos hashtags, sugiriendo que son utilizados para hacer referencia de diferentes recursos lingüísticos. Identificamos un conjunto de características basadas en diferentes fenómenos afectivos que parecen ser útiles para discriminar entre diferentes tipos de recursos lingüísticos. Adicionalmente analizamos la reversión de polaridad en tweets que contienen hashtags irónicos, observamos que el impacto de dicho fenómeno es diferente en cada uno de ellos. En el caso de los tweets que están etiquetados con el hashtag #sarcasm, a menudo hay una reversión total, mientras que en el caso de los tweets etiquetados con el hashtag #irony se produce una atenuación de la polaridad. Llevamos a cabo un estudio del impacto de la ironía y el sarcasmo en el análisis de sentimientos, observamos una disminución en el rendimiento de los sistemas de PLN desarrollados para dicha tarea cuando la ironía está presente. Por consiguiente, exploramos la posibilidad de utilizar nuestros resultados en detección de ironía para el desarrollo de un sistema de análisis de sentimientos que considere de la presencia de ironía, suponiendo que la detección de contenido irónico podría ayudar a mejorar la correcta identificación del sentimiento expresado en un texto dado. Con este objetivo, incorporamos emotIDM como la primera fase en un sistema de análisis de sentimientos para determinar la polaridad de mensajes en Twitter. Comparamos nuestros resultados con el estado del arte establecido en la tarea de evaluación "Semeval-2015 Task 11", demostrando la importancia de utilizar información afectiva en conjunto con características que alertan de la presencia de la ironía para desempeñar análisis de sentimientos en textos con lenguaje figurado que provienen de redes sociales. En resumen, demostramos la utilidad de aprovechar diferentes aspectos de información relativa al afecto y las emociones para tratar cuestiones relativas a la presencia de la ironí
Les plataformes de xarxes socials, com Twitter, oferixen als usuaris la possibilitat d'expressar-se de forma lliure i espontània fent ús de diferents recursos lingüístics com la ironia per aconseguir diferents propòsits de comunicació. Manejar aquest tipus de contingut representa un gran repte per a la lingüística computacional. La ironia està estretament vinculada amb l'expressió indirecta de sentiments, emocions i avaluacions. L'interés a detectar la presència d'ironia en textos de xarxes socials ha augmentat significativament en els últims anys. En aquesta tesi, introduïm el problema de detecció d'ironia en xarxes socials des de la perspectiva de la lingüística computacional. Proposem abordar aquesta tasca enfocant-nos, particularment, en el rol d'informació relativa a l'afecte i les emocions per detectar la presència d'aquest recurs lingüístic. Amb la intenció d'aprofitar el valor intrínsec de subjectivitat contingut en les expressions iròniques, presentem un model per a detectar la presència d'ironia denominat emotIDM, el qual està basat en una àmplia varietat de trets afectius. Per caracteritzar instàncies iròniques, utilitzàrem un ampli conjunt de recursos que cobrixen diferents àmbits afectius: des de sentiments (positius o negatius) fins emocions específiques definides de forma molt detallada. Els resultats obtinguts mostres que emotIDM té un rendiment competitiu en els experiments realitzats, validant l'efectivitat de l'enfocament proposat. Un altre objectiu de la tesi és investigar les diferències entre tweets etiquetats com a #irony i #sarcasm. La nostra finalitat és contribuir a un tema menys investigat en lingüística computacional: la separació entre l'ús d'ironia i sarcasme en xarxes socials, amb especial èmfasi amb els trets afectius. A més, estudiem un hashtag que ha sigut menys estudiat: #not. Els nostres resultats pareixen evidenciar que existixen diferències entre els tweets que contenen els hashtags esmentats, cosa que suggerix que s'utilitzen per fer referència de diferents recursos lingüístics. Identifiquem un conjunt de característiques basades en diferents fenòmens afectius que pareixen ser útils per a discriminar entre diferents tipus de recursos lingüístics. Addicionalment analitzem la reversió de polaritat en tweets que continguen hashtags irònics, observant que l'impacte del fenomen esmentat és diferent per a cadascun d'ells. En el cas dels tweet que estan etiquetats amb el hashtag #sarcasm, a sovint hi ha una reversió total, mentre que en el cas dels tweets etiquetats amb el hashtag #irony es produïx una atenuació de polaritat. Duem a terme un estudi de l'impacte de la ironia i el sarcasme en l'anàlisi de sentiments, on observem una disminució en el rendiment dels sistemes de PLN desenvolupats per a aquestes tasques quan la ironia està present. Per consegüent, vam explorar la possibilitat d'utilitzar els nostres resultats en detecció d'ironia per a desenvolupar un sistema d'anàlisi de sentiments que considere la presència d'ironia, suposant que la detecció de contingut irònic podria ajudar a millorar la correcta identificació del sentiment expressat en un text donat. Amb aquest objectiu, incorporem emotIDM com la primera fase en un sistema d'anàlisi de sentiments per determinar la polaritat de missatges en Twitter. Hem comparat els nostres resultats amb l'estat de l'art establert en la tasca d'avaluació "Semeval-2015 Task 11", demostrant la importància d'utilitzar informació afectiva en conjunt amb característiques que alerten de la presència de la ironia per exercir anàlisi de sentiments en textos amb llenguatge figurat que provenen de xarxes socials. En resum, hem demostrat la utilitat d'aprofitar diferents aspectes d'informació relativa a l'afecte i les emocions per tractar qüestions relatives a la presència d'ironia en Twitter.
Hernández Farias, DI. (2017). Irony and Sarcasm Detection in Twitter: The Role of Affective Content [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90544
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