Polyacrylonitrile nanofibre yarn; electrospinning and their post-drawing behaviour

Polyacrylontrile nanofibre yarns have been successfully produced from an electrospinning setup composing positively and negatively charged spinnerets, a rotating funnel and a yarn winder. Through hot drawing, yarns show compact morphology and improved uniformity and have a significant decrease in both yarn and fibre diameters. The hot drawing has improved the molecular orientation and crystallinity of the fibres. The yarn drawn to 5 times of its original length has been found to have the highest tensile strength and modulus.

Benchmark 4 : wrinkling during cup drawing

Benchmark-4 is designed to predict wrinkling during cup drawing. Two different punch geometries have been selected in order to investigate the changes of wrinkling amplitude and wave. To study the effect of material on wrinkling, two distinct materials including AA 5042 and AKDQ steel are also considered in the benchmark. Problem description, material properties, and simulation reports with experimental data are summarized.

Continuous polyacrylonitrile nanofiber yarns: Preparation and dry-drawing treatment for carbon nanofiber production

Precursor fibers with diameters in nanometer scale and highly aligned polymer chains in fibers are highly promising for the preparation of high-performance carbon nanofibers, but are challenging to make. In this study, we demonstrate for the first time that a carbon nanofiber precursor can be prepared by the electrospinning of polyacrylonitrile into a nanofiber yarn and by the subsequent drawing treatment of the yarn in dry conditions. The yarn shows excellent drawing performance, which can be drawn evenly up to 6 times of its original length without breaking. The drawing treatment improves the yarn and fiber uniformity, polymer chain orientation within the fibers, as well as yarn tension and modules, but shows decreased yarn and fiber diameter and elongation at break. The drawing temperature and force show influences on the drawing behavior. The highest strength and modules (362 ± 37 MPa and 9.2 ± 1.4 GPa, respectively) are found on the yarn drawn by 5 times its length, which increased by 800% and 1800% when compared to the as-spun yarn. Through un-optimized stabilization and carbonization treatments, we further demonstrate that the carbonized nanofiber yarn shows comparable tensile properties as the commercial carbon fibers. Electrospun nanofiber yarns may form next generation precursors for making high performance carbon fibers. This journal is

Place-based initiatives to tackle mature-age workers’ long-term unemployment in Australia, drawing on successful Nordic precedents

In order to tackle unemployment for the at-risk group of mature-age workers displaced by industry sector restructuring, exemplary place-based initiatives are needed focusing on a selected area of high disadvantage identified by Professor Tony Vinson’s 2015 Jesuit Social Services report Dropping off the Edge, with an Australian state government committed to supporting the initiative, as that report recommends. In order to make such a place-based initiative exemplary in its outcomes, so that it leads to uptake in other areas of high disadvantage, it needs to be thoroughly informed by successful Nordic precedents. In particular, the new Australian place-based initiative needs to be informed by Danish regionally-focused large-scale job skills programs involving transition into a proximate sector of employment growth; and by Norwegian measures for more even population distribution outside capital cities or in particular hard-hit regions within capital cities. An advantage of the proposed initiative is that it will also produce measurable results for children in families in which neither parent works, whose needs are normally tackled (if at all) by separate policy actions in separate tiers or departments of government. Australian children are disproportionately disadvantaged by the internationally extreme concentration of joblessness. Denmark’s Løntilskud and Virksomhedspraktik job training programs subsidised by municipalities and the national government, and supported by Danish trade unions, will be discussed in this paper for the positive effects they have for participants, including establishing or re-establishing unemployed people’s structured work habits and routines, improving their networks along with their social skills, and boosting their confidence. This paper will outline in detail the types of features the proposed new Australian place-based initiative will require, drawing on and drilling down further into data and analysis presented in the author’s recent book: Northern Lights: The Positive Policy Example of Sweden, Finland, Denmark and Norway.

WOW: wiki aided organization draWing

As the world evolves, organizations are becoming more and more complex, and the need to understand that complexity is increasing as well. With this demand, arises organizational engineering, which is a subject that emerged with the purpose to make organizations easier to understand, by putting in practice the concept of organizational self-awareness, which means that that the collaborators who are part of an organization, need to understand it and know what their role in it is. The DEMO methodology (Design Engineering Methodology for Organizations), came up with the purpose of representing these organizations’ self-awareness, through the definition and creation of consistent and coherent diagrams. Semantic wikis have features that can help in enterprise modelling. UEAOM (Universal Enterprise Adaptive Organization Model) is a model that allows the specification and dynamic evolution of languages, meta-models, models, and their representations as diagrams and tables. In this project, it was implemented a system based on UEAOM, and Semantic Media Wiki which allows a graphical creation and edition of diagrams. UEAOM can be divided into the meta-modeling level where a language is defined, and the modelling level where instances of classes of that language are created. The system we developed focuses on the modeling level, but will takes as a basis the project that focuses on meta-modeling. The DEMO language was used as an example for the implementation and tests of a graphical editor, based in web technologies and SVG, integrated with SemanticMediaWiki to allow an intuitive, coherent and consistent navigation and editing of organization diagrams.

A Comparison of Deep Drawing and Ironing of Metal Alloy Strip Produced conventionally and Non-conventionally via Semi Solid Material Processing

A semi solid thin strip continuous casting process was used to obtain 50%wt Pb/50%wtSn strip by single and twin roll processing at speed of 15 m/min. A 50%wt Pb/50%wtSn plate ingot was also cast for rolling conventionally into strips of 1.4 mm thickness and 45 mm width for comparison with those achieved non-conventionally. This hypoeutectic alloy has a solidification interval and fusion temperature of approximately 31 degrees C and 215 degrees C respectively. The casting alloy temperature was around 280 degrees C as measured by a type K immersion thermocouple prior to pouring into a tundish designed to maintain a constant melt flow on the cooling slope during semi solid material production. A nozzle with a weir ensures that the semi solid material is dragged smoothly by the lower roll, producing strip with minimum contamination of slag/oxide. The temperatures of the cooling slope and the lower roll were also monitored using K type thermocouples. The coiled semi solid strip, which has a thickness of 1.5 mm and 45 mm width, was rolled conventionally in order to obtain 1.2 mm thick strip. The coiled thixorolled strip had a thickness of 1.2 mm and achieved practically the same width as the conventional strips. Blanks of 40 mm diameter were cut from the strips in a mechanical press, ready for deep drawing and ironing for mechanical characterization. All the strips achieved from non-conventional processing had the same mechanical performance as those achieved conventionally. The limiting drawing ratio (LDR) achieved was approximately 2.0 for all strips. Microscopy examination was made in order to observe phase segregation during processing.

Does spatial visualization ability improve after studying technical drawing?

Two studies were carried out to analyze whether learning technical drawing improves a person's ability for spatial visualization. Visualization and inductive reasoning tests were applied at the beginning and end of a course in technical drawing in samples of first year engineering students. In both studies it was observed that a moderate percentage of students improved their Visualization test execution. The improvement was similar in men and women. There was no improvement on the inductive reasoning test. The results support the conclusion that the spatial visualization ability can be improved with training.