Angus - Bos indicus (Brahman or Nellore) reciprocal backcross embryo transfer calves belonging to 28 full-sib families were evaluated for differences in birth weight (BW), gestation length (GL), weaning weight (WW), carcass weight (HCW), longissimus muscle area (REA), fat thickness (adjusted (ADJFAT) and actual(ACTFAT)), intramuscular fat (MARB), and Warner-Bratzler shear force tenderness (WBSF). Family types with a greater proportion of Bos indicus in the sire in relation to the amount in the dam (F1 x A and B x F1) averaged longer GL and heavier BW than their respective reciprocal crosses (A x F1 and F1 x B). Calves had longer GL when the F1 parent was BA as opposed to AB. Small differences (statistically insignificant) were detected for BW, but no consistent difference was found between offspring of AB and BA parental types, with the exception of male F1-sired calves. F1 x A and B x F1 crosses also showed a large BW difference between males and females (about 5.0 kg), while A x F1 and F1 x B crosses showed no BW difference between males and females. Further examination within each sex showed a difference between male reciprocals that was two times that of females. Calves with a higher percentage of Bos indicus in the sire compared to the proportion in the dam showed the same trend, as they were still heavier at weaning, and produced heavier carcasses than the reciprocal crosses, though these differences were not significant. As a whole, A backcross calves had more ACTFAT, more ADJFAT, larger REA, more MARB, and lower WBSF than B backcross calves, though no significant differences were detected between reciprocal crosses for any of these traits. These results suggest that for weight related traits, especially BW, both the breed constitution of the calf and the cross that produces the calf play an important role in its ultimate performance for Bos indicus crossbred calves. For carcass and meat related traits, it appears that the breed make-up of the calf itself is more significant in influencing performance than the cross used to produce the calf.

Objectives were to: 1) Evaluate the effectiveness of presynchronization with GnRH before the CO‐Synch + CIDR protocol with timed AI (TAI) at 66 h in Bos indicus‐influenced cattle; 2) Characterize ovarian events associated with the presynchronization; 3) Evaluate the efficacy of measuring vaginal electrical resistance (VER) to assess follicular maturity at TAI; and 4) Compare serum concentrations of progesterone (P4) in ovariectomized cows bearing new or previously used CIDR devices with or without autoclaving. In Exp. 1 and 2, cattle received either GnRH or saline on day ‐7. The CO‐Synch + CIDR protocol included a CIDR insert and GnRH (GnRH‐1; day 0), removal of CIDR and PGF2α on day 7, and GnRH (GnRH‐2) and TAI 66 h after CIDR removal. In Exp. 1, pregnancy rate of females with BCS ≥ 5 tended to differ (P=0.085) between Presynch (38%) and CO‐Synch + CIDR (54%). In Exp. 2, ovulatory response to GnRH‐1 was greater (P<0.01) in the Presynchronization (58%) than in the CO‐Synch + CIDR (27.1%) group. Emergence of a follicular wave after GnRH‐1 and ovulation rate after GnRH‐2 did not differ between groups. More (P<0.01) females that developed a follicular wave after GnRH‐1 ovulated (82%) after GnRH‐2, compared to those that did not (29%). Mean VER (ohms) was greatest (101.4±0.8) on day 0 and declined (P<0.01) to 95.2±0.8 and 82±0.8, respectively, on days 7 and 10. We observed a low negative but significant relationship (r=0.38; P<0.001) between VER and follicular size on day 0, 7, and 10. VER difference (day 10 minus day 7) did not differ between females with small and large follicles at TAI. Mean concentrations of P4 during the 7‐day insertion period were greater (P<0.03) for new (3.7 ng/ml) and re‐used autoclaved (3.4 ng/ml) than for re‐used disinfected CIDRs (2.8 ng/ml). In summary, Presynch improved ovulation rate after GnRH‐1, but did not improve pregnancy rates compared to CO‐Synch + CIDR. Follicular maturity estimation was not feasible using VER as applied in this study. Autoclaving may be the best option when re‐using CIDR inserts because it creates greater concentrations of P4 during the first 48 h.

Sire and family effects were evaluated for calf growth, udder and teat conformation, and reproduction traits in 2- to 4- yr-old cows from the McGregor Genomics Project. Cows were produced by embryo transfer (ET) and natural service (NS) from the same 4 F1 Nellore-Angus sires, and were analyzed separately. Sire of cow was significant for calf birth weight (P = 0.014) among ET cows, but not NS cows. Among NS families, calves from cows out of Brahman-Hereford dams were 2.0 kg heavier (P = 0.064) at birth than calves from cows out of Brahman-Angus dams. Sire of cow accounted for variation in weaning weight (P = 0.006) and preweaning ADG (P = 0.005) of calves from ET dams, but not NS dams. Family nested within sire also accounted for variation (P = 0.061) in weaning weights of calves from ET dams. Sire of cow was significant for average teat length in ET (P < 0.001) and NS (P = 0.013) cows. Sire of cow was significant for average teat diameter (P = 0.022) among NS cows. Sire of cow also affected udder support score (P = 0.002), cow disposition at calf birth (P = 0.002), and cow weight at weaning (P = 0.045) in ET cows. Family and cow age also accounted for variation in cow disposition at calf birth (P = 0.015, P = 0.041, respectively) and cow weight at weaning (P = 0.001, P < .001, respectively) among ET cows. Calf year of birth also affected (P < .001) cow weight at weaning among ET cows. For NS dams, calf year of birth (P = 0.012), cow age (P < .001), and parity nested within cow age (P = 0.005) affected cow weight at weaning. Although reproduction data were not formally analyzed, there appear to be substantial differences for calving rate and average calving date among these cow families. Data from this project will be used for identification of genetic markers for these cow productivity traits.

The LD-process, called after the cities Linz and Donawitz, is used to convert pig iron into crude steel by blowing oxygen on top of the pig iron. A LD-LBE converter, Lance Bubbling Equilibrium, also stirs the melt trough a bottom stirring system. The bottom stirring in a LD-LBE converter is believed to have a positive effect alone on the phosphorous removal. Previous studies have shown that the temperature and slag composition are the main factors affecting phosphorus removal. Phosphorus binds to the slag easier at low temperature and to slag with certain levels of dissolved calcium (a process additive). Different praxes were tested and a better dephosphorisation was reached. The bottom stirrings effect on the dissolution of calcium additives is a possible explanation to the results and mechanisms presented in this study. The study also aimed to investigate the use of nitrogen as stirring gas instead of argon. Nitrogen is removed from the steel during the formation of carbon oxide gases. Nitrogen was used in varying amounts as stirring gas during the first half of the oxygen blow. It proved to be safe to use as long as there was a high content of carbon in the melt. However using nitrogen beyond half of the blow showed to be risky for nitrogen sensible steels; even in small amounts since there is not enough carbon left to degas the steel from nitrogen. Slopping happens when formed gas from the LD-process is trapped in the slag. The slag level rises and sometimes it floods the converter resulting in yield losses. The influence of the bottom stirring on slopping was studied, which resulted in the conclusion that slopping cannot be avoided by simply improving the bottom stirring. Although some verification studies remains to be done, if the suggestions based on the results of this thesis were employed, savings in the oxygen and stirring gas economies could be made. Not least improvements on the iron yield. / En järnmalmsbaserad stålproduktion börjar med att järnmalm matas i en masugn tillsammans med koks, kalk och tillsatsämnen. Ut kommer råjärn med höga kol och svavelhalter. Råjärnet transporteras till stålverket i så kallade torpedvagnar. I vissa stålverk, t.ex. SSAB Special Steels i Oxelösund, renas råjärnet från svavel i torpedvagnen. I andra stålverk svavelrenar man i separata skänkar. Svavelreningen sker med bland annat kalciumkarbid som binder till svavlet. Det svavelfattiga råjärnet måste sedan renas från kol för att bli stål. Det görs i en LD-konvertern (Linz Donawitz). LD-konvertern laddas med flytande råjärn som har en kolhalt på 4,5 procent och som är runt 1350 grader varmt. Råjärnet kyls genom att cirka 20 procent skrot tillsätts. En syrgaslans sänks sedan in i konvertern ovanför smältan och reningen startar.  Syrgaslansen blåser syrgas i ultraljudsfart vilket oxiderar en del av järnet, så väl som kol, kisel, mangan, fosfor and andra föroreningsämnen i råjärnet. Kol försvinner ur konvertern i form av kolmonoxidgas. Andra oxiderade föroreningar och järnoxid bildar tillsammans en så kallad slagg som flyter ovanpå smältan. Det tillsätts även så kallade slaggbildare som förbättrar upptaget av föroreningar i slaggen. Processen varar i cirka 17 minuter och är mycket beroende av slaggen som bildas. Kol försvinner ur konvertern i form av kolmonoxidgas. Under processens gång rör man om smältan med hjälp av gaser som spolas genom botten av konvertern. Omröringen jämnar ut smältans sammansättning och temperatur. När man inte länge behöver avlägsna kol stoppas processen. Stålets temperatur är då cirka 1700 grader och kolhalten ligger nära 0,05 procent. Stålet överförs sedan till en skänk för att skilja det ur slaggen. Stålet förädlas vidare i olika processer där sammansättningen justeras så att det möter kundens krav. Sedan gjuts stålet i strängar för transport till valsverk eller kunder. Denna studie behandlar bottenomrörningen under LD-processen i SSAB Special Steels's stålverk i Oxelösund. Omrörningen sker genom åtta porösa stenar i botten av konvertern som blåser med argon eller kväve. Gasflödet genom stenarna justeras genom ett ventilsystem. Under blåsningen rör man om med hjälp av förinställda program. Omrörningens primära funktion är att avlasta syrgaslansen. I fallen där ingen bottenomrörning finns måste syrgaslansen blåsa ”hårdare” på stålet för att avlägsna kol. Avlastningen som bottenomrörningen bidrar med gör att processen även kallas för LD-LBE, där LBE står för Lans Bubbling Equilibrium. Bottenomrörningen tros ha en positiv effekt på stålets rening från fosfor. Sedan tidigare vet man att temperatur och slaggsammansättning är de största faktorerna som påverkar fosforreningen. Fosfor tas lättare upp i slaggen vid låga temperaturen samt i slagg med högre kalkhalter. Olika omrörningsprogram testades och en bättre fosforrening nåddes. Bottenomrörningen visade sig ha positiva effekter som är teoretisk kopplade till kalksmältning. Två möjliga förklaringsmekanismer hittades. Studien undersökte även användningen av kväve som omrörningsgas istället för argon, då kväve är ekonomisk fördelaktig gentemot argon. Kväve finns inlöst i råjärnet som sätts in i konvertern. Kvävgasen försvinner ur stålet under och med hjälp av kolreningen. Det visade sig vara säkert att använda kväve från start fram till halva syrgasblåset på kvävekänsliga stålsorter, var efter man sedan byte till argon. Kväve som används sent under blåset visade ge högre kvävehalter. Urkok är en kraftig volymökning av slaggen som sker när bildad gas från reningen av smältan fångas i slaggen och får slaggen att ”koka över”. Urkok resulterar i ekonomiska förluster då slaggen som lämnar konvertern vid urkok är rik på järn. Bottenomrörningens eventuella påverkan på urkok studerades. Det visade sig att urkok inte kan undvikas genom att enbart optimera bottenomrörningen.

Thesis (MSc.(Anatomy)--Faculty of Health Sciences)-University of Pretoria, 2006. / Includes bibliographical references.

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Biologia Celular, 2008. / Submitted by Jaqueline Oliveira (jaqueoliveiram@gmail.com) on 2008-12-11T19:02:46Z No. of bitstreams: 1 DISSERTACAO_2008_JulianaAmorimAraujo.pdf: 3037793 bytes, checksum: a7399845548557e765e50c02f6d3d986 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-20T15:27:14Z (GMT) No. of bitstreams: 1 DISSERTACAO_2008_JulianaAmorimAraujo.pdf: 3037793 bytes, checksum: a7399845548557e765e50c02f6d3d986 (MD5) / Made available in DSpace on 2009-02-20T15:27:14Z (GMT). No. of bitstreams: 1 DISSERTACAO_2008_JulianaAmorimAraujo.pdf: 3037793 bytes, checksum: a7399845548557e765e50c02f6d3d986 (MD5) / A coagulação enzimática do leite para fabricação de queijo envolve a quebra de uma ligação peptídica da caseína por uma protease aspártica. Tradicionalmente, esta clivagem é feita em escala industrial pela ação da quimosina bovina que combina uma forte atividade de coagulação do leite com uma baixa atividade proteolítica. No presente estudo, é relatada a expressão, purificação e caracterização de quimosina recombinante bovina na levedura metilotrófica Pichia pastoris. Para alcançar altos níveis de produção, o cDNA do fragmento codante da pró-quimosina B bovina foi desenhado e sintetizado in vitro otimizando o codon usage para a expressão em P. pastoris. O gene sintético (CHYMb) foi clonado em vetores de expressão contendo os promotores PGK1 (expressão constitutiva) e AOX1 (expressão induzida) seguindo-se integração no genoma da levedura. Os clones transformantes com maior produção enzimática de cada sistema (P1 e A3, respectivamente) foram analisados em culturas simultâneas para comparação da produção enzimática. Maiores níveis de atividade de quimosina foram observados no clone sob o comando do promotor PGK1, que apresentou alta produção durante toda a cultura. Uma otimização na produção enzimática foi desenvolvida através de planejamentos fatoriais. A influência da densidade celular inicial, metanol e concentração da fonte de nitrogênio foram avaliados para aumentar a produção do clone A3. A interação dos fatores densidade celular inicial e concentração de metanol foi determinada como sendo o parâmetro mais importante, dobrando a produção. A influência de diferentes concentrações da fonte de nitrogênio e carbono, previamente selecionados (farelo de soja e açúcar invertido), foi também analisada para aumentar a produção enzimática no clone P1. Foi demonstrado por análise estatística que maiores concentrações de cada fator aumentam a produção. O perfil de atividade enzimática foi avaliada em fermentador com as condições determinadas nas otimizações. A atividade encontrada nos dois casos (A3 e P1) foi superior àquelas encontradas na fermentação em frascos. A quimosina recombinante foi posteriormente purificada apenas por uma etapa de cromatografia de exclusão molecular. Foi demonstrada a presença de enzima já processada no sobrenadante da cultura e uma fração de proteínas glicosiladas. A especificidade pela caseína foi demonstrada ser semelhante à quimosina comercial recombinante produzida por Aspergillus niger (Chr. Hansen). A alta produção de quimosina recombinante com alta especificidade em P. pastoris faz esse sistema de expressão atrativo para produção industrial desta enzima. _______________________________________________________________________________ ABSTRACT / Enzymatic milk coagulation for cheese manufacturing involves the cleavage of the scissile bond in casein by an aspartic protease. Bovine chymosin B is commonly used at the industrial level for milk coagulation because it combines a strong clotting activity with a low general proteolytic activity. In the present study, we report the expression, purification and characterization of recombinant chymosin B expressed in the methylotrophic yeast Pichia pastoris. To achieve high levels of production, the cDNA fragment coding for prochymosin was designed and synthesized based on codon usage optimization for expression in P. pastoris. The synthetic gene (CHYMb) was cloned into expression vectors based on the PGK1 promoter (constitutive expression) and AOX1 promoter (inducible expression). The resulted constructs were integrated in the yeast genome. Transformant clones producing high levels of enzyme activity from each system (P1 and A3, respectively) were analyzed in a simultaneous culture for comparison of enzymatic production. High levels of chymosin activity were observed in the clone controlled by the PGK1 promoter which showed high production levels throughout the culture. Optimization for enzymatic production was developed through factorial design. The influence of the initial cellular density, methanol and nitrogen source concentration were accessed for enzymatic production from clone A3. The interaction of the initial cellular density and methanol concentration was responsible for doubling enzyme production. The influence of different concentrations of nitrogen and carbon sources (soy extract and inverted sugar, respectively) was also observed to increase enzymatic production in clone P1. Statistic analysis demonstrated that higher concentrations of each factor increased enzyme production. The profile of enzymatic activity was evaluated in fermentors under the conditions determined during optimizations. In this case, the activities observed in clones A3 and P1 were superior to those found when theses clones were grown in shake flasks. The recombinant chymosin was purified by a single molecular exclusion chromatographic step. Purified enzyme derived from supernatant fraction was shown to be present in its processed form and a fraction of glycosylated protein was also detected. The specificity for casein was shown to be similar to that from commercial recombinant chymosin produced by Aspergillus niger (Chr. Hansen). The high production and high specificity of recombinant chymosin derived from P. pastoris renders this expression system as an attractive alternative for large scale industrial production of this enzyme.

Orientador: Maurício Mello de Alencar / Coorientador: Rymer Ramiz Tullio / Banca: Andrea Roberto Bueno Ribeiro / Banca: Hirasilva Borba / Resumo: A bovinocultura de corte deve ter foco no desenvolvimento de sistemas sustentáveis de produção. Este trabalho teve como objetivo avaliar o desempenho de cruzamentos entre raças bovinas, visando animais precoces em acabamento e que produzam carne de qualidade, além de avaliar estes animais quanto a fatores ligados à expressão do temperamento. Foram realizadas avaliações da reatividade, desempenho, características de carcaça e qualidade da carne, in natura e maturada, de machos não castrados e fêmeas 3/4 Angus + 1/4 Nelore (ANTA), 1/2 Angus + 1/4 Simental + 1/4 Nelore (ANTS), 1/2 Limousin + 1/4 Angus + 1/4 Nelore (LITA) e 1/2 Limousin + 1/4 Simental + 1/4 Nelore (LITS), terminados em confinamento ou pastagem com suplementação e abatidos, respectivamente, aos 13 ou 18 meses de idade. Verificou-se que filhos de touros Limousin foram mais reativos, principalmente quando as mães eram Simental x Nelore. Os animais ficaram mais reativos ao longo do tempo e o sistema de produção parece não ter influenciado esta característica. Os animais ANTS foram mais pesados ao desmame (268 kg). Machos ANTA foram mais pesados ao abate quando confinados (474 kg), e os mais leves a pasto (448 kg); o inverso aconteceu com o gado LITA. O ganho diário não diferiu entre os genótipos no sistema a pasto, mas foi significativamente maior para os filhos de touros Angus no confinamento. Os filhos de touros Limousin foram mais eficientes quanto a conversão alimentar e apresentaram maior rendimento de carcaça do que os filhos de touros Angus (ANTA e ANTS). Todos os cruzamentos possibilitaram o abate precoce dos animais e a realização de um ciclo curto de produção. A força de cisalhamento não foi influenciada por nenhum dos efeitos estudados, sendo as médias da carne in natura iguais a 7,1 kgf/cm2, 7,0 kgf/cm2, 7,6 kgf/cm2 e 7,7 kgf/cm2 para os grupos genéticos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Beef production should focus on developing sustainable production systems. This study aimed to evaluate the performance of crossbred cattle to produce young animals with good quality meat, and to evaluate the expression of temperament in these animals. Reactivity, performance, carcass traits and meat quality, fresh and mature, were evaluated in 3/4 Angus + 1/4 Nelore (ANTA), 1/2 Angus + 1/4 Simmental + 1/4 Nelore (ANTS), 1/2 Limousin + 1/4 Angus + 1/4 Nelore (LITA) e 1/2 Limousin + 1/4 Simmental + 1/4 Nelore (LITS) males and females, finished in feedlot or pasture with supplementation, and slaughtered at 13 or 18 months of age. It was found that offspring of Limousin bulls were more reactive, especially when the dams were 1/2 Simmental x 1/2 Nelore. Animals were more reactive over time and production system seems to have no influence on this trait. ANTS animals showed higher weight at weaning (268 kg). ANTA males showed higher weight at slaughter when confined (474 kg), and lower when finished on pasture (448 kg); the reverse happened with LITA cattle. The daily gain did not differ between the genotypes in the pasture system, but was significantly higher for offspring of Angus bulls in feedlot system. The offspring of Limousin bulls were more efficient in feed conversion and carcass yield than the offspring of Angus bulls (ANTA and ANTS). All crossings enabled the slaughter of young animals and short cycle of production system. Shear force was not affected by any of the effects studied, and the estimated means were equal to 7.1, 7.0, 7.6 and 7.7 kgf/cm2 for the genetic groups ANTA, ANTS, LITA e LITS, respectively... (Complete abstract click electronic access below) / Mestre

O projeto teve como objetivo avaliar os efeitos da inclusão do ionóforo narasina no suplemento mineral e proteinado sobre o consumo de suplemento pelos animais e sobre o desempenho de bovinos de corte durante a fase de recria mantidos em pastagem. Foram utilizados 150 machos nelore inteiros em um delineamento experimental de blocos completos, sendo a unidade experimental o lote de 5 animais. O experimento teve duração de 140 dias, composto por 5 perídos de 28 dias cada. Os tratamentos utilizados foram: CON Mistura mineral Controle (sem narasina), 1800 CON com adição de 1800 mg de narasina/kg da mistura mineral, 2750 - CON com adição de 2750 mg de narasina/kg da mistura mineral, PROT Suplemento Proteinado com 22% de proteína bruta (PB; sem narasina) e PROT 360 PROT com 360 mg de narasina/kg do suplemento. Os tratamentos foram confrontados através de contrastes ortogonais. A inclusão de narasina na mistura mineral aumentou o ganho médio diário (GMD) quando comparado ao CON no primeiro período (P = 0,01; 28d), entretanto, não houve efeito nos demais períodos. A inclusão de narasina diminuiu o consumo de suplemento nos três períodos iniciais (P &lt; 0,01 para ambos) quando comparado ao CON. Os tratamentos 1800 e 2750 foram semelhantes para a ingestão de suplemento (P = 0,89) e GMD (P = 0,70) em todo o experimento. Os animais dos tratamentos PROT e PROT 360 consumiram mais suplemento em relação aos animais dos tratamentos com mistura mineral (P &lt; 0,01 para todos os períodos) e proporcionaram animais mais pesados (P &lt; 0,01). A inclusão de narasina no suplemento proteinado otimizou seu uso nos dois primeiros períodos, pois obteve o mesmo GMD (P = 0,75 e P = 0,48, respectivamente), porém com menor ingestão de suplemento (P = 0,03 e P &lt; 0,01, respectivamente). Em conclusão, a narasina afeta o consumo de suplementos e desempenho em situações específicas, porém, de maneira geral a narasina não foi eficaz em melhorar a performance de bovinos de corte em fase de recria a pasto. / The present trial was carried out to evaluate the effect of narasin inclusion in mineral and protein supplements in the supplement intake and performance of grazing beef cattle. A hundred and fifty Nellore bull calves with 17.03 &#177; 0.06 months of age, initial body weight (BW) of 219.65 &#177; 1.62 kg, were assigned to the following treatments: mineral supplement (CON); mineral supplement + 1800 (1800) or 2750 (2750) mg narasin/kg of supplement; Protein mineral supplement (PROT) or PROT + 360 mg of narasin/kg of supplement (PROT 360). The bull calves were kept in a rotational stocking system with Brachiaria brizantha cv Marandu, during 5 periods of 28 days each. Adding narasin in the mineral supplement increased (P = 0.01) average daily gain (ADG) on the 1st period and decreased (P &lt; 0.01) supplement intake on the 1st, 2nd and 3rd periods compared to CON. Bull calves in the 1800 and 2750 treatments had similar supplement intakes (P = 0.89) and ADG (P = 0.70) at the end of the experiment. In addition, the animals of the PROT and PROT 360 treatments consumed more supplement than the animals of the mineral mix treatments (P &lt; 0.01 for all periods) and provided heavier animals (P &lt; 0.01). Narasin decreased the protein supplement intake and did not affect ADG on the 1st and 2nd periods. The narasin affects the intake of supplements and performance in specific situations, however in overall, narasin addition in mineral and protein supplements did not affect the performance of grazing bull calves.

Steel is the worlds most used metal and 2016 the produced amount of steel was measured to a total1630 MT where the Blast Furnace (BF) - Basic Oxygen Steelmaking (BOS) process, which is the mostcommon steel process, stands for 75% of the world’s current crude steel production.The BOS process works by blowing oxygen at high velocity through a hot metal bath consisting of hotmetal from the blast furnace mixed with fluxing agents as slag formers and up to 30 weights% scrap.Due to the high focus on environmental aspects throughout the world, the importance of utilizing andrecycling scrap and by-products such as slag and dust has increased. But when byproducts are recycled,the risk of impurities in the refined hot metal increases. To be able to control the impurities and reducethe risk of getting off-specification end product, it is important to understand when and where theimpurities end up.Zinc and chromium are two of these impurities that may cause issues to the process. To prevent thisfrom happening BlueScope Steel, a steel plant based in Wollongong, Australia, with a productioncapacity of 3 million tons of crude steel, wants to find out where these elements come from and howthey partition. For zinc, it is observed that most of it will end up in the offgas, while for chromium it isnoted that the majority exits with the steel and slag. It is assumed for both elements that the missingamount enters with the shredded steel scrap (shred) to meet the required mass balance using industrialdata. Results showed that the shred needs to contain between 0.312% and 0.515% zinc in order tosatisfy the zinc balance for year 2014 to 2019. For chromium, the range is from 0.315% to 0.371%.Data analyses carried out using SIMCA UMETRICS, which is a multivariate program used to performPrincipal Component Analysis (PCA) and Partial Least Squares (PLS) regression, and normal regressionsdone in Excel showed that zinc in the crude steel cannot be used to calculate or predict the partitioningfactors for zinc between slag, melt and off gases, due to a R2 (Goodness of fit) of 0.144, where the highera R2 value is the better the fit to the model. Slag showed better results with an R2 of 0.473 This regressionwas only done for heats with Zn contents above the detection limit, so it will most likely only beapplicable to heats where relatively high amounts of zinc are expected to end up in the slag. The amountof zinc that ends up in the offgas was above 95% for all the heats modelled.For chromium, results for predicting the partitioning between slag and melt showed greater promise,an R2 of 0.663 was obtained for regression of chromium in crude steel, and an R2 of 0.566 was obtainedfor regression of chromia in the slag. Both values are considered acceptable when analyzing plant data.When comparing the two, using the regression from chromium in the crude steel gives a slightly moreaccurate result, with a partitioning difference of only +/- 0.03 and a 97-99% accuracy, compared to +/-0.05 for chromia in the slag with a 95-98% accuracy.The model is used to compare how different amounts of shred will impact the partitioning of the twoelements analyzed. It also looks at how newer generations of filter cake, containing higher amounts ofzinc will impact the partitioning of zinc between the phases, especially the concentration of zinc thatreports to the dust.

No description available.