394 resultados para solution structures
Resumo:
While governments are engaged in developing social policy responses to address wicked issues such as poverty, homelessness, drug addiction and crime, long term resolution of these issues through government policy making and state-based programmatic action has remained elusive. The use of vehicles for joint action and partnership between government and the community sector such as co-management has been offered as a way of harnessing productive capability and innovative capacity of both these sectors to resolve these complex problems. However, it is suggested that while there is a well advanced agenda with the intent for collaboration and partnership, working with the models for undertaking this joint action are not well understood and have not been fully developed or evaluated. This chapter examines new approaches to resolving the wicked issue of homelessness through applying the lens of co-management to understand the complexities of this issue and its resolution. The chapter analyses an attempt to move away from traditional bureaucratic structures of welfare departments, operating through single functional ‘silos’ to a new horizontal ‘hub-based’ model of service delivery that seeks to integrate actors across many different service areas and organizations. The chapter explores case studies of co-management in the establishment, development and operation of service hubs to address homelessness. We argue that the response to homelessness needs a ‘wicked solution’ that goes beyond simply providing shelter to those in need. The case of the hub models of community sector organizations working across organizational boundaries is evaluated to determine whether this approach can be considered successful co-managing of an innovative initiative, and understanding the requirements for developing, improving and extending this model. The role of the third sector in co-managing public services is examined through the in-depth case studies and the results are presented together with an assessment of how co-management can contribute to service quality and service management in public services.
Resumo:
Sandwich shells have recently emerged as aesthetically pleasing, efficient and economical structural systems, with a number of applications. They combine the advantages of sandwich layer technology together with those of shell action. With different materials and thicknesses used in the sandwich layers, their performance characteristics largely remain un-quantified and there are no guidelines at present for their design. This research paper provides verification, through finite element modeling and testing, for the application of this technology to dome styled dwellings with research currently being conducted into the further application to roofing and floor structures.
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Gender identity-conscious HR structures signal an organization’s perspective on gender diversity. The signal produces perceptions that the organization values gender diversity leading to a gender diverse workforce. In turn, a gender diverse workforce provides a firm with a competitive advantage which should result in higher performance. This paper tests the mediating effects of gender diversity (at non-management and management levels) in the relationship between gender identity-conscious HR structures and performance. The findings indicate that non-management gender diversity partially mediates the relationship between HR structures and productivity, and management gender diversity partially mediates the relationship between HR structures and perceived market performance.
Resumo:
The reconstruction of large defects (>10 mm) in humans usually relies on bone graft transplantation. Limiting factors include availability of graft material, comorbidity, and insufficient integration into the damaged bone. We compare the gold standard autograft with biodegradable composite scaffolds consisting of medical-grade polycaprolactone and tricalcium phosphate combined with autologous bone marrow-derived mesenchymal stem cells (MSCs) or recombinant human bone morphogenetic protein 7 (rhBMP-7). Critical-sized defects in sheep - a model closely resembling human bone formation and structure - were treated with autograft, rhBMP-7, or MSCs. Bridging was observed within 3 months for both the autograft and the rhBMP-7 treatment. After 12 months, biomechanical analysis and microcomputed tomography imaging showed significantly greater bone formation and superior strength for the biomaterial scaffolds loaded with rhBMP-7 compared to the autograft. Axial bone distribution was greater at the interfaces. With rhBMP-7, at 3 months, the radial bone distribution within the scaffolds was homogeneous. At 12 months, however, significantly more bone was found in the scaffold architecture, indicating bone remodeling. Scaffolds alone or with MSC inclusion did not induce levels of bone formation comparable to those of the autograft and rhBMP-7 groups. Applied clinically, this approach using rhBMP-7 could overcome autograft-associated limitations.
Resumo:
Flexible tubular structures fabricated from solution electrospun fibers are finding increasing use in tissue engineering applications. However it is difficult to control the deposition of fibers due to the chaotic nature of the solution electrospinning jet. By using non-conductive polymer melts instead of polymer solutions the path and collection of the fiber becomes predictable. In this work we demonstrate the melt electrospinning of polycaprolactone in a direct writing mode onto a rotating cylinder. This allows the design and fabrication of tubes using 20 μm diameter fibers with controllable micropatterns and mechanical properties. A key design parameter is the fiber winding angle, where it allows control over scaffold pore morphology (e.g. size, shape, number and porosity). Furthermore, the establishment of a finite element model as a predictive design tool is validated against mechanical testing results of melt electrospun tubes to show that a lesser winding angle provides improved mechanical response to uniaxial tension and compression. In addition, we show that melt electrospun tubes support the growth of three different cell types in vitro and are therefore promising scaffolds for tissue engineering applications.
Resumo:
Problems involving the solution of advection-diffusion-reaction equations on domains and subdomains whose growth affects and is affected by these equations, commonly arise in developmental biology. Here, a mathematical framework for these situations, together with methods for obtaining spatio-temporal solutions and steady states of models built from this framework, is presented. The framework and methods are applied to a recently published model of epidermal skin substitutes. Despite the use of Eulerian schemes, excellent agreement is obtained between the numerical spatio-temporal, numerical steady state, and analytical solutions of the model.
Resumo:
The crystal structures of the 1:1 proton-transfer compounds of isonipecotamide (piperidine-4-carboxamide) with the monocyclic heteroaromatic carboxylic acids, isonicotinic acid, picolinic acid, dipicolinic acid and pyrazine-2,3-dicarboxylic acid have been determined at 200 K and their hydrogen-bonding patterns examined. The compounds are respectively anhydrous 4-carbamoylpiperidinium pyridine-4-carboxylate (1), the partial hydrate 4-carbamoylpiperidinium pyridine-2-carboxylate 0.25 water (2), the solvate 4-carbamoylpiperidinium 6-carboxypyridine-2-carboxylate methanol monosolvate (3), and anhydrous 4-carbamoylpiperidinium 3-carboxypyrazine-2-carboxylate (4). In compounds 1 and 3, hydrogen-bonding interactions give two-dimensional sheet structures which feature enlarged cyclic ring systems, while in compounds 2 and 4, three-dimensional structures are found. The previously described cyclic R2/2(8) hydrogen-bonded amide-amide dimer is present in 2 and 3. The hydrogen-bonding in 2 involves the partial-occupancy water molecule while the structure of 4 is based on inter-linked homomolecular hydrogen-bonded cation-cation and anion-anion associated chains comprising head-to-tail interactions. This work further demonstrates the utility of the isonipecotamide cation in the generation of chemically stable hydrogen-bonded systems, particularly with aromatic carboxylate anions, providing crystalline solids.
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Based on the eigen crack opening displacement (COD) boundary integral equations, a newly developed computational approach is proposed for the analysis of multiple crack problems. The eigen COD particularly refers to a crack in an infinite domain under fictitious traction acting on the crack surface. With the concept of eigen COD, the multiple cracks in great number can be solved by using the conventional displacement discontinuity boundary integral equations in an iterative fashion with a small size of system matrix. The interactions among cracks are dealt with by two parts according to the distances of cracks to the current crack. The strong effects of cracks in adjacent group are treated with the aid of the local Eshelby matrix derived from the traction BIEs in discrete form. While the relatively week effects of cracks in far-field group are treated in the iteration procedures. Numerical examples are provided for the stress intensity factors of multiple cracks, up to several thousands in number, with the proposed approach. By comparing with the analytical solutions in the literature as well as solutions of the dual boundary integral equations, the effectiveness and the efficiencies of the proposed approach are verified.
Resumo:
The productivity of the construction industry worldwide has been declining over the past forty years. One approach to improving the situation is by the introduction of lean construction. The IKEA model has also been shown to be beneficial when used in the construction context. A framework is developed in which the lean construction concept is embodied within the IKEA model by integrating Virtual Prototyping (VP) technology and its implementation is described and evaluated through a real-life case implementing the lean production philosophy. The operational flows of the IKEA model and lean construction are then compared to analyze the feasibility of IKEA-based lean construction. It is concluded that the successful application of the IKEA model in this context will promote the implementation of lean construction and improve the efficiency of the industry.
Resumo:
The recently released Mathematics, Engineering & Science in the National Interest report (May, 2012) highlights the universal perspective that an education in these disciplines is essential to a nation’s future prosperity. Although studies in STEM (Science, Technology, Engineering, Mathematics) are being implemented across many schools, progress to date has been slow especially with respect to incorporating engineering experiences in the middle and primary grades. Our concerns for the limited attention given to engineering in STEM and the low uptake of university engineering courses in universities, prompted us to conduct a longitudinal project on engineering education across grade levels 7-9.
Resumo:
Poorly characterized phases (PCP's) may constitute up to 30 volume percent of some C2M carbonaceous chondrite matrices [1] and are an important key to an understanding of matrix evolution. PCPs are usually fine-grained (
Resumo:
Structure and chemistry of poorly characterized phases (PCP). We suggest here that approximately 10 angstrom PCP, a dominant matrix variety, has a structure equivalent to iron-rich tochilinite [6Fe (sub 0.9) S 5(Fe, Mg) (OH) (sub 2) ] which consists of coherently interstratified mackinawite and brucite sheets. approximately 17 angstrom PCP, previously described as an SBB-type mixed-layer structure, is a commensurate intergrowth of serpentine and tochilinite layers. A wide range of cation substitutions is possible within both tochilinite and serpentine-tochilinite structural types. Various forms of PCP observed in carbonaceous chondrites are intergrowths of tochilinite, serpentine, serpentine-tochilinite and/or valleriite-type minerals.--Modified journal abstract.