Feasibility of using in situ fusion for the determination of Co, Cr and Mn in Portland cement by direct solid sampling graphite furnace atomic absorption spectrometry

In situ fusion on the boat-type graphite platform has been used as a sample pretreatment for the direct determination of Co, Cr and Mn in Portland cement by solid sampling graphite furnace atomic absorption spectrometry (SS-GF AAS). The 3-field Zeeman technique was adopted for background correction to decrease the sensitivity during measurements. This strategy allowed working with up to 200 mu g of sample. The in situ fusion was accomplished using 10 mu L of a flux mixture 4.0% m/v Na(2)CO(3) + 4.0% m/v ZnO + 0.1% m/v Triton (R) X-100 added over the cement sample and heated at 800 degrees C for 20 s. The resulting mould was completely dissolved with 10 mu L of 0.1% m/v HNO(3). Limits of detection were 0.11 mu g g(-1) for Co, 1.1 mu g g(-1) for Cr and 1.9 mu g g(-1) for Mn. The accuracy of the proposed method has been evaluated by the analysis of certified reference materials. The values found presented no statistically significant differences compared to the certified values (Student`s t-test, p<0.05). In general, the relative standard deviation was lower than 12% (n = 5). (C) 2009 Elsevier B.V. All rights reserved.

A GUI for online presentation of steel and steelmaking ladle temperature data and simulation.

Continuous casting is a casting process that produces steel slabs in a continuous manner with steel being poured at the top of the caster and a steel strand emerging from the mould below. Molten steel is transferred from the AOD converter to the caster using a ladle. The ladle is designed to be strong and insulated. Complete insulation is never achieved. Some of the heat is lost to the refractories by convection and conduction. Heat losses by radiation also occur. It is important to know the temperature of the melt during the process. For this reason, an online model was previously developed to simulate the steel and ladle wall temperatures during the ladle cycle. The model was developed as an ODE based model using grey box modeling technique. The model’s performance was acceptable and needed to be presented in a user friendly way. The aim of this thesis work was basically to design a GUI that presents steel and ladle wall temperatures calculated by the model and also allow the user to make adjustments to the model. This thesis work also discusses the sensitivity analysis of different parameters involved and their effects on different temperature estimations.

An Experimental Study of Submerged Entry Nozzles (SEN) Focusing on Decarburization and Clogging

The submerged entry nozzle (SEN) is used to transport the molten steel from a tundish to a mould. The main purpose of its usage is to prevent oxygen and nitrogen pick-up by molten steel from the gas. Furthermore, to achieve the desired flow conditions in the mould. Therefore, the SEN can be considered as a vital factor for a stable casting process and the steel quality. In addition, the steelmaking processes occur at high temperatures around 1873 K, so the interaction between the refractory materials of the SEN and molten steel is unavoidable. Therefore, the knowledge of the SEN behaviors during preheating and casting processes is necessary for the design of the steelmaking processes  The internal surfaces of modern SENs are coated with a glass/silicon powder layer to prevent the SEN graphite oxidation during preheating. The effects of the interaction between the coating layer and the SEN base refractory materials on clogging were studied. A large number of accretion samples formed inside alumina-graphite clogged SENs were examined using FEG-SEM-EDS and Feature analysis. The internal coated SENs were used for continuous casting of stainless steel grades alloyed with Rare Earth Metals (REM). The post-mortem study results clearly revealed the formation of a multi-layer accretion. A harmful effect of the SENs decarburization on the accretion thickness was also indicated. In addition, the results indicated a penetration of the formed alkaline-rich glaze into the alumina-graphite base refractory. More specifically, the alkaline-rich glaze reacts with graphite to form a carbon monoxide gas. Thereafter, dissociation of CO at the interface between SEN and molten metal takes place. This leads to reoxidation of dissolved alloying elements such as REM (Rare Earth Metal). This reoxidation forms the “In Situ” REM oxides at the interface between the SEN and the REM alloyed molten steel. Also, the interaction of the penetrated glaze with alumina in the SEN base refractory materials leads to the formation of a high-viscous alumina-rich glaze during the SEN preheating process. This, in turn, creates a very uneven surface at the SEN internal surface. Furthermore, these uneven areas react with dissolved REM in molten steel to form REM aluminates, REM silicates and REM alumina-silicates. The formation of the large “in-situ” REM oxides and the reaction of the REM alloying elements with the previously mentioned SEN´s uneven areas may provide a large REM-rich surface in contact with the primary inclusions in molten steel. This may facilitate the attraction and agglomeration of the primary REM oxide inclusions on the SEN internal surface and thereafter the clogging. The study revealed the disadvantages of the glass/silicon powder coating applications and the SEN decarburization. The decarburization behaviors of Al2O3-C, ZrO2-C and MgO-C refractory materials from a commercial Submerged Entry Nozzle (SEN), were also investigated for different gas atmospheres consisting of CO2, O2 and Ar. The gas ratio values were kept the same as it is in a propane combustion flue gas at different Air-Fuel-Ratio (AFR) values for both Air-Fuel and Oxygen-Fuel combustion systems. Laboratory experiments were carried out under nonisothermal conditions followed by isothermal heating. The decarburization ratio (α) values of all three refractory types were determined by measuring the real time weight losses of the samples. The results showed the higher decarburization ratio (α) values increasing for MgO-C refractory when changing the Air-Fuel combustion to Oxygen-Fuel combustion at the same AFR value. It substantiates the SEN preheating advantage at higher temperatures for shorter holding times compared to heating at lower temperatures during longer holding times for Al2O3-C samples. Diffusion models were proposed for estimation of the decarburization rate of an Al2O3-C refractory in the SEN. Two different methods were studied to prevent the SEN decarburization during preheating: The effect of an ZrSi2 antioxidant and the coexistence of an antioxidant additive and a (4B2O3 ·BaO) glass powder on carbon oxidation for non-isothermal and isothermal heating conditions in a controlled atmosphere. The coexistence of 8 wt% ZrSi2 and 15 wt% (4B2O3 ·BaO) glass powder of the total alumina-graphite refractory base materials, presented the most effective resistance to carbon oxidation. The 121% volume expansion due to the Zircon formation during heating and filling up the open pores by a (4B2O3 ·BaO) glaze during the green body sintering led to an excellent carbon oxidation resistance. The effects of the plasma spray-PVD coating of the Yttria Stabilized Zirconia (YSZ) powder on the carbon oxidation of the Al2O3-C coated samples were investigated. Trials were performed at non-isothermal heating conditions in a controlled atmosphere. Also, the applied temperature profile for the laboratory trials were defined based on the industrial preheating trials. The controlled atmospheres consisted of CO2, O2 and Ar. The thicknesses of the decarburized layers were measured and examined using light optic microscopy, FEG-SEM and EDS. A 250-290 μm YSZ coating is suggested to be an appropriate coating, as it provides both an even surface as well as prevention of the decarburization even during heating in air. In addition, the interactions between the YSZ coated alumina-graphite refractory base materials in contact with a cerium alloyed molten stainless steel were surveyed. The YSZ coating provided a total prevention of the alumina reduction by cerium. Therefore, the prevention of the first clogging product formed on the surface of the SEN refractory base materials. Therefore, the YSZ plasma-PVD coating can be recommended for coating of the hot surface of the commercial SENs.

Diverse eukaryotes have retained mitochondrial homologues of the bacterial division protein FtsZ

Mitochondrial fission requires the division of both the inner and outer mitochondrial membranes. Dynamin-related proteins operate in division of the outer membrane of probably all mitochondria, and also that of chloroplasts – organelles that have a bacterial origin like mitochondria. How the inner mitochondrial membrane divides is less well established. Homologues of the major bacterial division protein, FtsZ, are known to reside inside mitochondria of the chromophyte alga Mallomonas, a red alga, and the slime mould Dictyostelium discoideum, where these proteins are likely to act in division of the organelle. Mitochondrial FtsZ is, however, absent from the genomes of higher eukaryotes (animals, fungi, and plants), even though FtsZs are known to be essential for the division of probably all chloroplasts. To begin to understand why higher eukaryotes have lost mitochondrial FtsZ, we have sampled various diverse protists to determine which groups have retained the gene. Database searches and degenerate PCR uncovered genes for likely mitochondrial FtsZs from the glaucocystophyte Cyanophora paradoxa, the oomycete Phytophthora infestans, two haptophyte algae, and two diatoms – one being Thalassiosira pseudonana, the draft genome of which is now available. From Thalassiosira we also identified two chloroplast FtsZs, one of which appears to be undergoing a C-terminal shortening that may be common to many organellar FtsZs. Our data indicate that many protists still employ the FtsZ-based ancestral mitochondrial division mechanism, and that mitochondrial FtsZ has been lost numerous times in the evolution of eukaryotes.

Aggregate planning for seasonal demand : reconciling theory with practice

Purpose: The paper reports on the ramifications for production planning when monthly sales exhibit predictable seasonal highs and lows. The literature first acknowledged and dealt with the (aggregate planning) problem 50 years ago. Nevertheless, there is neither evidence that industry has adopted any of the mathematical techniques that were subsequently developed, nor a convincing explanation as to why not. Hence this research sets out to discover the methods manufacturers use to cope with seasonal demand, and how germane the published algorithms really are.

Design/methodology/approach: Forty-two case studies were compiled by interviewing senior managers and then conducting plant tours. No prior assumptions were made and the list of questions covered the gamut of production planning.

Findings: The main finding is that manufacturers select a straightforward production strategy, right from the outset, so the fundamental cost-balancing format is not relevant. The majority pick a “chase” strategy, since most organizations subscribe to a “just in time” ethos. Whenever a different strategy is preferred the rationale springs from skilled labour considerations or binding facilities constraints. The chosen strategy serves as a road map for resources acquisitions, and the master production schedule is constructed directly. So, the complex issue of how to disaggregate an optimal aggregate plan never even arises. Managers do not seek perfect solutions, but strive to eliminate, or contain, the most significant marginal costs. The nature of the business determines the most appropriate tactics to employ.

Originality/value: These findings break the mould as far as orthodox aggregate planning is concerned and show why theory is at odds with practice, whilst reaffirming the importance of concepts such as “flexibility”, “integration”, and “just-in-time production”.

Manufacturing process effects on the mode I interlaminar fracture toughness and nanocreep properties of CFRP

Quickstep ™ is a fluid filled floating mould technology which was recently developed by an Australian company of the same name. The Quickstep and conventional autoclave manufacture of composites were compared by investigating the mode I interlaminar fracture toughness and nanocreep propeties of HexPly914 carbon epoxy composites. It was found that composites cured using the Quickstep technology had significantly higher fracture toughness (1.8 times) than the composites cured via autoclave for this system. DMTA (dynamic mechanical thermal analysis) results showed a higher Tg (glass transition temperature) for the material manufactured by the Quickstep than that cured by the autoclave. FTIR (Fourier transform infrared spectroscopy) spectra did not indicate any difference in cure chemistry between the two processes. Nanocreep experiments were performed to explore the viscoelastic properties of the epoxy matrix of composites. The KelvinVoigt three-element model was applied to analyse the indentation creep behaviour of both composites.

Building capacity for rural health : the role of boundary crossers in coalition maturity for partnerships with external agents

The concept of partnership has entered policy rhetoric and is urged as good practice in a variety of domains including health. Rural communities tend to have fewer resources available for the provision of services such as health than their metropolitan counterparts, and so could be expected to benefit from partnerships with external agencies. Indicators of coalition maturity for working in partnership with external agents in order to build stronger communities are distilled from the group development and partnership research literature and considered in the light of the experiences of the University Department of Rural Health in community engagement. The chapter draws on experiences of two rural community coalitions working to plan and negotiate health service provision. The coalitions were analysed against the indicators. A key indicator of maturity and readiness for working in partnership with external agents is related to the behaviour of ‘boundary crossers’. Boundary crossers are defined as people who move freely between two or more domains and who understand the values, cultures and language, and have the trust, of both. Domains can be within a community or be the community and an external sector. Community health professionals, especially those in senior positions, often act as boundary crossers between the community and broader domains such as regional/state health services or policy, although other community members can fill the role. Other key indicators of coalition maturity for working in partnership with external agents include local leadership that empowers the community, a willingness of community coalitions to take risks and mould opportunities to meet their vision, and a culture of critical reflection and evaluation of past actions.

This chapter analyses the impact of boundary crossing behaviour on community readiness and partnerships with external agents that are intended to build rural community capacity to plan and negotiate health service provision. It is argued that the characteristics and modus operandi of boundary crossers who are members of rural community coalitions affect the level of maturity of the coalitions and community readiness to work with external agents. An understanding of the characteristics and modus operandi of boundary crossers provides valuable insights for external agents in designing their approach to partnerships that build rural community capacity for health.

Building capacity for rural health : the role of boundary crosser and the impact of their behaviours on community readiness partnerships

The concept of partnership has entered policy rhetoric and is urged as good practice in a variety of domains including health. Rural communities tend to have fewer resources available for the provision of services such as health than their metropolitan counterparts, and so could be expected to benefit from partnerships with external agencies. Indicators of coalition maturity for working in partnership with external agents in order to build stronger communities are distilled from the group development and partnership research literature and considered in the light of the experiences of the University Department of Rural Health in community engagement. The chapter draws on experiences of two rural community coalitions working to plan and negotiate health service provision. The coalitions were analysed against the indicators. A key indicator of maturity and readiness for working in partnership with external agents is related to the behaviour of ‘boundary crossers’. Boundary crossers are defined as people who move freely between two or more domains and who understand the values, cultures and language, and have the trust, of both. Domains can be within a community or be the community and an external sector. Community health professionals, especially those in senior positions, often act as boundary crossers between the community and broader domains such as regional/state health services or policy, although other community members can fill the role. Other key indicators of coalition maturity for working in partnership with external agents include local leadership that empowers the community, a willingness of community coalitions to take risks and mould opportunities to meet their vision, and a culture of critical reflection and evaluation of past actions.

This chapter analyses the impact of boundary crossing behaviour on community readiness and partnerships with external agents that are intended to build rural community capacity to plan and negotiate health service provision. It is argued that the characteristics and modus operandi of boundary crossers who are members of rural community coalitions affect the level of maturity of the coalitions and community readiness to work with external agents. An understanding of the characteristics and modus operandi of boundary crossers provides valuable insights for external agents in designing their approach to partnerships that build rural community capacity for health.

Casting yield improvement in graphite iron castings

A well designed runner and feeding system should produce castings with minimal defects and low pour weight. This thesis investigates how the filling regime and solidification of the mould influences defects in the castings produced from that mould. Design guidelines to reduce such defects are proposed and tested. An existing shrinkage fault in a Grey Iron disc brake casting is simulated using a commercial finite-difference computer program. Three criteria are used to predict the defect and the effect of changes to the feeder geometry. Critical Fraction Solidification analysis is used to determine whether the feeder remains in liquid contact with the casting during solidification and this approach is shown to correctly predict the presence or absence of porosity* The feeder block is extended below the ingate of the casting to improve liquid contact between the casting and feeder without significantly increasing the feeder mass. Plant trials confirm the change to the feeder eliminates the porosity defect. The runner system and mould venting for a thin walled Ductile Iron casting are investigated. Trials show that by setting the total mould vent area to be greater than the net ingate area of the castings, the cold-shut frequency is halved. A method for runner system design based on peak linear flow velocity in the runner during mould filling is proposed. A new pressurised runner system produces castings with significantly fewer defects and reduced pour weight when runner areas are designed to maintain peak velocity below 1 m/s. Peak velocity and magnesium levels are demonstrated to be critical factors in the elimination of cold-shut defects. A pressurised runner system is also shown to isolate inclusion defects from castings more effectively than an unpressurised system. From this work, a technique is proposed which allows the yield of an existing runner and feeder system for iron castings to be improved with confidence in the results.

Outdoor fungi and child asthma health service attendances

Asthma is a significant global public health issue. Severe asthma exacerbations can be triggered by environmental factors and require medical care from health services. Although it is known that fungal exposure may lead to allergic sensitization, little is understood about its impact on asthma exacerbations. This review aims to examine whether outdoor fungi play a significant role in child asthma exacerbations. Systematic search of seven electronic databases and hand searching for peer-reviewed studies published in English, up to 31 August 2013. Inclusion criteria were study population aged <18 yr, diagnosis of asthma, attended a health service; outdoor fungi exposure was reported. Quality and risk of bias assessments were conducted. Due to significant heterogeneity, meta-analysis was not conducted. Of the 1896 articles found, 15 were eligible. Findings were not consistent, possibly due to methodological variations in exposure classifications, statistical methods and inclusion of confounders. Cross-sectional studies found no or weak associations. All but one time series studies indicated an association that varied between fungal species. Increasing evidence indicates that asthmatic children are susceptible to asthma exacerbations when exposed to outdoor fungal spores. There is limited understanding of the contributions of different fungal species. Research is needed to investigate interactions of outdoor fungi with pollen, air pollutants and respiratory viruses.

Invasive infections due to filamentous fungi other than Aspergillus: epidemiology and determinants of mortality

The epidemiology of invasive fungal disease (IFD) due to filamentous fungi other than Aspergillus may be changing. We analysed clinical, microbiological and outcome data in Australian patients to determine the predisposing factors and identify determinants of mortality. Proven and probable non-Aspergillus mould infections (defined according to modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria) from 2004 to 2012 were evaluated in a multicentre study. Variables associated with infection and mortality were determined. Of 162 episodes of non-Aspergillus IFD, 145 (89.5%) were proven infections and 17 (10.5%) were probable infections. The pathogens included 29 fungal species/species complexes; mucormycetes (45.7%) and Scedosporium species (33.3%) were most common. The commonest comorbidities were haematological malignancies (HMs) (46.3%) diabetes mellitus (23.5%), and chronic pulmonary disease (16%); antecedent trauma was present in 21% of cases. Twenty-five (15.4%) patients had no immunocompromised status or comorbidity, and were more likely to have acquired infection following major trauma (p <0.01); 61 (37.7%) of cases affected patients without HMs or transplantation. Antifungal therapy was administered to 93.2% of patients (median 68 days, interquartile range 19-275), and adjunctive surgery was performed in 58.6%. The all-cause 90-day mortality was 44.4%; HMs and intensive-care admission were the strongest predictors of death (both p <0.001). Survival varied by fungal group, with the risk of death being significantly lower in patients with dematiaceous mould infections than in patients with other non-Aspergillus mould infections. Non-Aspergillus IFD affected diverse patient groups, including non-immunocompromised hosts and those outside traditional risk groups; therefore, definitions of IFD in these patients are required. Given the high mortality, increased recognition of infections and accurate identification of the causative agent are required.

O desafio da formação do policial militar do estado do Rio de Janeiro: utopia ou realidade possível?

This work of research treats of the police military formation in the state of the Rio de Janeiro. The academic approach to be adopted in respect to verify the state actions for the adaptation of the course of the soldier¿s formation to the national curriculum mould (NCM) for the police education, proposed by the National General Office of Public Security in the year of 2000. It¿s part of a group of actions of the federal government to format the police education in all country. The aim of this action is to form policemen to act in an appropriate way in a democratic society. The result of the research revealed that the Military Police of the state of the Rio de Janeiro, did not effect actions for the adoption the of NCM in the period of 2000-2005, as well as it¿s not preparing the militaries polices to act with base in the values of a democratic society. The empirical material show us the view the of the military police in relation to the education in the Military Police, as well as its performance day by day in the resolution of the social conflicts.

A formação profissional dos oficiais da primeira turma do curso de bacharelado em segurança pública e do cidadão (2002/2005) no estado do Amazonas: estudo de caso

Este trabalho de pesquisa trata da formação profissional do oficial policial militar no Estado do Amazonas. Trata-se da 1ª turma do Curso de Bacharelado em Segurança Pública e do Cidadão Curso de Formação de Oficiais (CFO), iniciado em agosto de 2002 e concluído em março de 2005. A abordagem acadêmica foi adotada no sentido de se verificar a adaptação do Curso à Matriz Curricular Nacional (MCN) para o ensino policial, versada nas Bases Curriculares para a Formação dos Profissionais da Área de Segurança do Cidadão, apresentada pelo Ministério da Justiça, através da Secretaria Nacional de Segurança Pública (SENASP) em 2000. A Matriz Curricular Nacional integra um conjunto de ações do Governo Federal para balizar o ensino policial, buscando assim, capacitar os oficiais para atuar de maneira adequada em uma sociedade democrática. O conteúdo empírico do trabalho revela o dimensionamento da formação do oficial policial militar consubstanciado pelo ensino, pesquisa e extensão, realizado em parceria entre a Polícia Militar do Estado do Amazonas e a Universidade do Estado do Amazonas, no cenário em que desempenhará suas funções para dirimir os conflitos da ordem pública.

Educação, escola e participação

O objetivo da pesquisa é fazer um levantamento dos sentidos de educação e escola dentre os alunos do 2o Grau, Formação Geral, do município do Rio de Janeiro. O corpus do trabalho constitui-se de entrevistas com alunos do Colégio Estadual José Accioli em Marechal Hermes, zona oeste do município. A metodologia de análise dos depoimentos é aquela fornecida pela escola francesa de Análise de Discurso na linha de Michel Pêcheux. Nessa perspectiva, o que se busca não é o sentido que estes jovens dão à educacão e escola, mas os vários sentidos que convivem sob estes temas. A pesquisa, entretanto, não se esgota nessa abordagem e procura elucidar as condições históricas e ideológicas de produção dos sentidos apontados. Paralelamente à investigação dos sentidos de escola e educação, a pesquisa propõe-se, também, a examinar os sentidos atribuídos à noção de participação. A inclusão deste terceiro elemento não é gratuita e procura inserir a discussão acerca da educacão no contexto mais geral da questão democrática.A participação, então, não é entendida como o engajamento episódico e localizado à uma associação ou agremiação qualquer, mas como o principio (utópico, por certo) organizador de toda e qualquer relação social. Assim, apesar de não se adotar uma postura teórica que "julga" os sentidos apreendidos a partir de uma concepção de educação e participação estabelecidas a priori, também não se pode negar que a simples inclusão do terceiro elemento já pressupõe , pelo menos, uma filiação a um determinado sentido. De fato, esta pesquisa alinha-se com o pensamento de Dumerval Trigueiro, que em seus trabalhos sempre ressaltou a íntima relação entre os conceitos de educação e participação. O educador atribui ao pensamento liberal, principalmente à tecnocracia, a responsabilidade do alijamento do povo (pelo poder e pelo saber) da construção da polis. Entretanto, é essa mesma população desestimulada a participar ativamente da vida política que será convocada a fazê-lo com a inclusão do principio de gestão democrática do ensino na nova Lei de Diretrizes e Bases. Por isso, a questão da participação ganhou relevo neste trabalho e ampliou-se no sentido de investigar como os sujeitos situam-se frente às relacões de poder na nossa sociedade e como a educação e a escola afetam e são afetadas por essas relações.

Variação das características físico-químicas e microbiológicas das salmouras empregadas na salga de queijos tipo mussarela durante o período de sua utilização

Foram analisadas 40 amostras de salmouras empregadas na salga por submersão de queijos tipo mussarela, em uma indústria de laticínios do Estado de São Paulo, Brasil, com o objetivo de se conhecer a variação das características físico-químicas e microbiológicas durante o período de sua utilização. Os valores médios do pH, concentração de cloreto de sódio e de proteínas solúveis, desde o preparo da salmoura até o 21° dia de utilização, variaram de 7,21 a 5,76, 27,1 a 24,5 e de zero a 0,126 mg/ml, respectivamente. Por outro lado, os valores médios das contagens de microrganismos mesófilos e do número mais provável de coliformes totais e de origem fecal variaram de 5,8 x 10 UFC/ml a 6,9 x 10(4) UFC/ml, zero a 1,6 x 10(5)/100ml e zero a 1,1 x 10(5)/100ml, respectivamente. Além disso, os valores médios das contagens de bolores e leveduras e de Staphylococcus coagulase positiva, variaram de 0,4 x 10 UFC/ml a 2,0 x 10³ UFC/ml e de zero a 1,3 x 10 UFC/ml, respectivamente. Os resultados encontrados sugerem a existência de condições higiênicas inadequadas durante o preparo e utilização das salmouras, de modo a representar uma importante fonte de contaminação para os queijos. em decorrência deste fato, existe a possibilidade do comprometimento da qualidade dos queijos, de modo a representar risco potencial à população consumidora.