852 resultados para General material designation
Resumo:
The oxides of cobalt have recently been shown to be highly effective electrocatalysts for the oxygen evolution reaction (OER) under alkaline conditions. In general species such as Co3O4 and CoOOH have been investigated that often require an elevated temperature step during their synthesis to create crystalline materials. In this work we investigate the rapid and direct electrochemical formation of amorphous nanostructured Co(OH)2 on gold electrodes under room temperture conditions which is a highly active precursor for the OER. During the OER some conversion to crystalline Co3O4 occurs at the surface, but the bulk of the material remains amorphous. It is found that the underlying gold electrode is crucial to the materials enhanced performance and provides higher current density than can be achieved using carbon, palladium or copper support electrodes. This catalyst exhibits excellent activity with a current density of 10 mA cm-2 at an overpotential of 360 mV with a high turnover frequency of 2.1 s-1 in 1 M NaOH. A Tafel slope of 56 mV dec-1 at low overpotentials and a slope of 122 mV dec-1 at high overpotentials is consistent with the dual barrier model for the electrocatalytic evolution of oxygen. Significantly, the catalyst maintains excellent activity for up to 24 hr of continuous operation and this approach offers a facile way to create a highly effective and stable material.
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Analytical solutions of partial differential equation (PDE) models describing reactive transport phenomena in saturated porous media are often used as screening tools to provide insight into contaminant fate and transport processes. While many practical modelling scenarios involve spatially variable coefficients, such as spatially variable flow velocity, v(x), or spatially variable decay rate, k(x), most analytical models deal with constant coefficients. Here we present a framework for constructing exact solutions of PDE models of reactive transport. Our approach is relevant for advection-dominant problems, and is based on a regular perturbation technique. We present a description of the solution technique for a range of one-dimensional scenarios involving constant and variable coefficients, and we show that the solutions compare well with numerical approximations. Our general approach applies to a range of initial conditions and various forms of v(x) and k(x). Instead of simply documenting specific solutions for particular cases, we present a symbolic worksheet, as supplementary material, which enables the solution to be evaluated for different choices of the initial condition, v(x) and k(x). We also discuss how the technique generalizes to apply to models of coupled multispecies reactive transport as well as higher dimensional problems.
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Micropropagation is unequalled for the rapid clonal propagation of improved cultivars from several Australian breeding programmes. This has been particularly true of the pineapple breeding programme, but it has also found an important role in the strawberry breeding programme where high-health mother stock is of paramount concern. In the banana and ginger industries, while access to new cultivars has been of importance, micropropagation has been adopted by the industry to ensure that planting materials are free from serious pests and diseases. Bananas can be used as planting material as early as the first generation ex vitro and is responsible for the establishment of laboratories and nurseries specializing in the production of pathogen-tested plants. The ginger industry, on the other hand, has used micropropagated plants as a source of disease and pest-free stock to establish a clean 'seed' scheme based on the production of conventional planting material.
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A detailed study of the normalized correlations between the incubation period tc and the properties of various materials tested in a rotating disk device indicates that, at very high intensities, the strength properties influence the duration of tc. The analysis of extensive data from other laboratories for cavitation and liquid impingement erosion also indicates that, while both energy and strength properties influence the duration of tc, the latter ones predominate for a majority of cases. A fatigue-type failure occurs during tc. For estimating the time required to pierce a metallic specimen in a rotating device a relationship tp = 160 tc0.44 is proposed. A detailed study of normalized correlations between erosion resistance (inverse of erosion rate) and tc values of different materials tested in the rotating disk shows that correlations are good. Analysis of data from eight other investigators clearly points out the validity and the usefulness of this type of prediction.
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How toddlers with special needs adjust to the daycare setting A multiple case study of how the relationships with adults and children are built The aim in this study is to describe how toddlers with special needs adjust to daycare. The emotional well-being and involvement in daycare activities of toddlers are especially investigated in this study. The relationship and how it is built between an adult and a child, a child and a child is examined. The daycare is examined through the socio-cultural theory as a pedagogical institution, where the child adapts by participating in social and cultural activities with the others. The development of the child is the result of the experiences that are gained through the constant relationship between the child, the family and social context. By the attachment theory the inner self-regulation, that allows the child safely adapt to new situations, develops most in the relationship between the child under 3years of age and the attending adult. The relationships between toddlers in daycare are usually built by the coincidental encounters in play and daily activities. In these relationships, the toddler gets the information of themselves and the other children. The complexity of the rules in the setting that organize the social action is challenging for the children and they need constant support from the adults. The participants of the study were five toddlers with special needs. When applying to daycare they were less than three years old and they got the specialist statement for their special needs, and the reference for daycare. The children were observed by recording their attending in the daycare once in the 3-4 months from the first day in daycare. Approximately 15 hours of material that was analysed with the Transana-program. The qualitative material was analysed by first collecting a descriptive model that explains and theorises the phenomenon. By the summery of the narrative it is placed a hypothesis that is tested by quantitative methods using correlations and variance analyses and general linear modeling that is used to count the differences between repeated measures and connections between different variables. The results of the study are built theoretically for the consistent conception between the theory and the findings in research. The toddlers in the study were all dependent on the support given by the adults in all the situations in the daycare. They could not associate with the other children without the support of the adults and their involvement in activities was low. The engagement of an adult in interaction was necessary for the children’s involvement in activities, and the co-operation with the other children. The engagement of teachers was statistically significantly higher than the engagement of other professions.
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One history in a multicomplex world The quintessence of history and grand historical narratives in the historical consciousness of class teacher students The study analyses the conception of history amongst class teacher students at the University of Helsinki. It also explores the expectations about the future that the students have on the basis of their views on history. The conceptions of the students are analysed against the background of the notion of one history which has been part of Western thought in the modern era and which is at the centre of the theoretical framework of this study. The Enlightenment project and the erosion of the role of the Church paved the way for the notion that history is an linear narrative of the progress of humankind and in which, implicitly, the Western countries are endowed with a special role as the vanguards of progress. In recent times these assumptions have been criticised by postmodernists and proponents of New History. The material of the study consists of interviews of twenty-two 19 26 years old class teacher students at the University of Helsinki. The topics in the interviews were the developments of the past and the future trajectories. The students conceived history as a field of knowledge that provides a unifying view on the world and helps to make today s world intelligible. Finnish history and global history were invested with features of a grand narrative of progress. In global history, progress and development were seen as characteristic of the Western world primarily. The students regarded the post-war Finnish history as a qualified success story in that they deplored the erosion of collectivist values and the rise of selfishness in recent decades. History was not conceived as a process of progress that would self-evidently continue in the future, but rather more as a field of contingency and cyclical change.The students regarded the increasing predominance of the market forces over democratically elected agencies, the antagonism between the West and the other parts of the world, and environmental risks as the major threats. Notwithstanding this general.pessimism about the future, the students had a very positive view of their own personal prospects. Keywords: historical consciouness, one history, future expectations
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The aim of this study was to find out the meaning family has for a pupil who studies in a special class, or how important family is for the pupil s emotional life, the development of his self-confidence, freetime activities, attitudes on school, plans for further studies and his general social development. The theoretical base of this study was formed by social scientists' theories on postmodern family, which is due to urbanization and urban life style, and theories on family pluralism, the powerful effects that changes in family life have on pupils in special education, the weak self-confidence and low sosioeconomic background among those pupils and the effects of family's sosioeconomic status on pupil's willingness to get education or the theory on the accumulation of education. Study problems were set in the direction determined by these theories and in order to study the accurateness of the theories. The method used in the study was theme interview, which is sometimes also called half-structured interview. The material for the study was collected in October 1998 in a special school in Helsinki. The material contains answers given by pupils in theme interviews and background information about pupils' families, which where collected from the pupils' parents by mail. Content analysis was used to analyze the material. The study showed that it is very important to pupils' attitudes on school and their self-confidence that their families are entire and that the families give them support. The children, whose parents are interested in school education and discuss a lot about things, seem to have positive attitudes on school and good self-confidence, too. The parental support also has an effect on how the pupils spend their free time and on their hobbies, too. Obviously the families have quite an important meaning for pupils in special class, but if the families don t support them, the consequence is problems particularly for the development of self-confidence. The theory on the low sosioeconomic background among students in special education gets support from this study, but nothing can be said about it's effect on further studies. On account of the results it can be suggested that special schools must arrange occasions where the pupils' parents are clearly informed about the important meaning of their support for the pupils studies and the development of the pupils' self-confidence. The most important sources for the theoretical background were the books written by Jallinoja, Kivinenand Rinne, Moberg, Scanzoni and P. Takala. The most important sources for the method were the books written by Hirsjärvi and Hurme and Pietilä. Keywords: family, special class, pupil in special education, support, self-confidence, postmodern family
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The objective of the present study was to increase knowledge about the atelier culture of recent history, especially about the ways in which atelier clothes were made. I look at the ways of dress-making in the production of a renowned atelier, Salon Kaarlo Forsman. I also give a general outline of the atelier. The studying method I used was triangulation, which is a typical approach in case studies of recent history. My data include 23 dresses by the Salon Forsman, theme interviews of four of the Salon workers and one mannequin, data from my research work, as well as press material and archives. The basis of the analysis of these materials was a theme frame that I had put together with the help of pre-understanding. I then completed and defined the theme frame on the basis of the analysis of the data. I also analyzed the dresses in the fashion photos in the press material. Salon Kaarlo Forsman represents a certain cultural period, the years 1937-1986, and a place where a woman could have individual clothes made for her, from hats to fur coats. The atelier was particularly known for embroidery with beads, draping, and fantastic cuttings designed by the owner, fashion designer Kaarlo Forsman. I draw an outline of the work and practices of the atelier, but also that of Kaarlo Forsman’s life work, as he had a great influence on the sewing methods atelier clothes. Mr. Forsman was able to stretch the first period of modern fashion well into the third period by refusing new, labor-saving methods and sticking to individually designer clothes to the end of his enterprise. The crucial practices in the atelier that I present in this study are fitting, designing, finishing and sewing, as well as beading and the decoration of dresses. I compare the activity, practices and dress-making methods in the Forsman atelier to that of Haute Couture in Paris, which served as model for Finnish fashion houses. I point out the similarities and differences.
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The Cape York Peninsula Land Use Strategy (CYPLUS) is a joint Queensland/Commonwealth initiative to provide a framework for making decisions about how to use and manage the natural resources of Cape York Peninsula in ways that will be ecologically sustainable. As part of the Natural Resources Analysis Program (NRAP) of CYPLUS, the Fisheries Division of the Queensland Department of Primary Industries has mapped the marine vegetation (mangroves and seagrasses) for Cape York Peninsula. The project ran from July 1992 to June 1994. Field work was undertaken in November 1992, May 1993, and April 1994. Final report on project: NRO6 – Marine Plan (Seagrass/Mangrove) Distribution. Dataset URL Link: Queensland Coastal Wetlands Resources Mapping data. [Dataset]
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The crucial questions that define democracy relate to its depth and width: who can participate in decision making and what kind of things can be commonly decided? Theories deeper than representative democracy emphasize discussion, in which by evaluating justifications it is possible to achieve consensus in ideal situation. The aim of my research is to develop tools for promoting the participation of third graders in decision making in the classroom. In addition I study the development of depth and width of democracy in the classroom, the development of skills and competencies in the decision making and the challenges of the project. My research method is participative action research. I collected my data between October 2007 and March 2008. I used videos and observation diaries as my primary data. Additional data consisted of the interviews of the students, the conversations between the adults and the material produced by the teacher. Since we discussed the matters students had highlighted in specific lessons, my analysis proceeds according to these lessons constructing a general view of the process. The width and depth of classroom democracy are difficult to define. Though the system we had created enabled third graders to discuss matters they found important the participation was unequal: some of the students couldn’t among other things give justifications for their opinions. This poses challenges for models that emphasize deliberation since these theories presuppose that everyone has concordant competencies. But then again only critical citizens who are able to make justifications and to evaluate them are able to oppose indoctrination. This makes teaching these competencies justified. Different decision making procedures define the classroom democracy. Deliberation doesn’t necessarily provide deeper information about the preferences of the participants than mere voting. But then again voting doesn’t express the reasons which support one’s preferences. Structured conversation can equalize the time used for every participant’s opinions, but doesn’t solve the challenge of unequal competencies. Children’s suggestion box diversified the possibilities to participate, and also the silent ones used it during the research. The asymmetry in deliberation might also be caused by the social structure of the students. Teacher’s directing and participation encouraging role in deliberation was significant. Diversifying the participation by different roles could equalize the asymmetry in participation.
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Characterisation and investigation of a number of key wood properties, critical for further modelling work, has been achieved. The key results were: • Morphological characterisation, in terms of fibre cell wall thickness and porosity, was completed. A clear difference in fibre porosity, size, wall thickness and orientation was evident between species. Results were consistent with published data for other species. • Viscoelastic properties of wood were shown to differ greatly between species and in the radial and tangential directions, largely due to anatomical and chemical variations. Consistent with published data, the radial direction shows higher stiffness, internal friction and glass transition temperature than the tangential directions. The loss of stiffness over the measured temperature range was greater in the tangential direction than the radial direction. Due to time dependant molecular relaxation, the storage modulus and glass transition temperature decreased with decreasing test frequency, approaching an asymptotic limit. Thus the viscoelastic properties measured at lower frequencies are more representative of static material. • Dynamic interactions between relative humidity, moisture content and shrinkage of four Australian hardwood timbers can be accurately monitored on micro-samples using a specialised experimental device developed by AgroParisTech – ENGREF. The device generated shrinkage data that varied between species but were consistent (repeatable) within a species. Collapse shrinkage was clearly evident with this method for Eucalyptus obliqua, but not with other species, consistent with industrial seasoning experience. To characterise the wood-water relations of this species, free of collapse, thinner sample sections (in the R-T plane) should be used.
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This project was designed to provide the structural softwood processing industry with the basis for improved green and dry grading to allow maximise MGP grade yields, consistent product performance and reduced processing costs. To achieve this, advanced statistical techniques were used in conjunction with state-of-the-art property measurement systems. Specifically, the project aimed to make two significant steps forward for the Australian structural softwood industry: • assessment of technologies, both existing and novel, that may lead to selection of a consistent, reliable and accurate device for the log yard and green mill. The purpose is to more accurately identify and reject material that will not make a minimum grade of MGP10 downstream; • improved correlation of grading MOE and MOR parameters in the dry mill using new analytical methods and a combination of devices. The three populations tested were stiffness-limited radiata pine, strength-limited radiata pine and Caribbean pine. Resonance tests were conducted on logs prior to sawmilling, and on boards. Raw data from existing in-line systems were captured for the green and dry boards. The dataset was analysed using classical and advanced statistical tools to provide correlations between data sets and to develop efficient strength and stiffness prediction equations. Stiffness and strength prediction algorithms were developed from raw and combined parameters. Parameters were analysed for comparison of prediction capabilities using in-line parameters, off-line parameters and a combination of in-line and off-line parameters. The results show that acoustic resonance techniques have potential for log assessment, to sort for low stiffness and/or low strength, depending on the resource. From the log measurements, a strong correlation was found between the average static MOE of the dried boards within a log and the predicted value. These results have application in segregating logs into structural and non-structural uses. Some commercial technologies are already available for this application such as Hitman LG640. For green boards it was found that in-line and laboratory acoustic devices can provide a good prediction of dry static MOE and moderate prediction for MOR.There is high potential for segregating boards at this stage of processing. Grading after the log breakdown can improve significantly the effectiveness of the mill. Subsequently, reductions in non-structural volumes can be achieved. Depending on the resource it can be expected that a 5 to 8 % reduction in non structural boards won’t be dried with an associated saving of $70 to 85/m3. For dry boards, vibration and a standard Metriguard CLT/HCLT provided a similar level of prediction on stiffness limited resource. However, Metriguard provides a better strength prediction in strength limited resources (due to this equipment’s ability to measure local characteristics). The combination of grading equipment specifically for stiffness related predictors (Metriguard or vibration) with defect detection systems (optical or X-ray scanner) provides a higher level of prediction, especially for MOR. Several commercial technologies are already available for acoustic grading on board such those from Microtec, Luxscan, Falcon engineering or Dynalyse AB for example. Differing combinations of equipment, and their strategic location within the processing chain, can dramatically improve the efficiency of the mill, the level of which will vary depending of the resource. For example, an initial acoustic sorting on green boards combined with an optical scanner associated with an acoustic system for grading dry board can result in a large reduction of the proportion of low value low non-structural produced. The application of classical MLR on several predictors proved to be effective, in particular for MOR predictions. However, the usage of a modern statistics approach(chemometrics tools) such as PLS proved to be more efficient for improving the level of prediction. Compared to existing technologies, the results of the project indicate a good improvement potential for grading in the green mill, ahead of kiln drying and subsequent cost-adding processes. The next stage is the development and refinement of systems for this purpose.
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Aims and objectives To determine consensus across acute care specialty areas on core physical assessment skills necessary for early recognition of changes in patient status in general wards. Background Current approaches to physical assessment are inconsistent and have not evolved to meet increased patient and system demands. New models of nursing assessment are needed in general wards that ensure a proactive and patient safety approach. Design A modified Delphi study. Methods Focus group interviews with 150 acute care registered nurses (RNs) at a large tertiary referral hospital generated a framework of core skills that were developed into a web-based survey. We then sought consensus with a panel of 35 senior acute care RNs following a classical Delphi approach over three rounds. Consensus was predefined as at least 80% agreement for each skill across specialty areas. Results Content analysis of focus group transcripts identified 40 discrete core physical assessment skills. In the Delphi rounds, 16 of these were consensus validated as core skills and were conceptually aligned with the primary survey: (Airway) Assess airway patency; (Breathing) Measure respiratory rate, Evaluate work of breathing, Measure oxygen saturation; (Circulation) Palpate pulse rate and rhythm, Measure blood pressure by auscultation, Assess urine output; (Disability) Assess level of consciousness, Evaluate speech, Assess for pain; (Exposure) Measure body temperature, Inspect skin integrity, Inspect and palpate skin for signs of pressure injury, Observe any wounds, dressings, drains and invasive lines, Observe ability to transfer and mobilise, Assess bowel movements. Conclusions Among a large and diverse group of experienced acute care RNs consensus was achieved on a structured core physical assessment to detect early changes in patient status. Relevance to clinical practice Although further research is needed to refine the model, clinical application should promote systematic assessment and clinical reasoning at the bedside.
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The use of capacitors for electrical energy storage actually predates the invention of the battery. Alessandro Volta is attributed with the invention of the battery in 1800, where he first describes a battery as an assembly of plates of two different materials (such as copper and zinc) placed in an alternating stack and separated by paper soaked in brine or vinegar [1]. Accordingly, this device was referred to as Volta’s pile and formed the basis of subsequent revolutionary research and discoveries on the chemical origin of electricity. Before the advent of Volta’s pile, however, eighteenth century researchers relied on the use of Leyden jars as a source of electrical energy. Built in the mid-1700s at the University of Leyden in Holland, a Leyden jar is an early capacitor consisting of a glass jar coated inside and outside with a thin layer of silver foil [2, 3]. With the outer foil being grounded, the inner foil could be charged with an electrostatic generator, or a source of static electricity, and could produce a strong electrical discharge from a small and comparatively simple device.