877 resultados para Engineering, Electronics and Electrical|Artificial Intelligence


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This paper describes and analyses an innovative engineering management course that applies a project management framework in the context of a feasibility study for a prospective research project. The aim is to have students learn aspects of management that will be relevant from the outset of their professional career while simultaneously having immediate value in helping them to manage a research project and capstone design project in their senior year. An integral part of this innovation was the development of a web-based project management tool. While the main objectives of the new course design were achieved, a number of important lessons were learned that would guide the further development and continuous improvement of this course. The most critical of these is the need to achieve the optimum balance in the mind of the students between doing the project and critically analyzing the processes used to accomplish the work.

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Creativity is increasingly recognised as an essential component of engineering design. This paper describes an exploratory study into the nature and importance of creativity in engineering design problem solving in relation to the possible impact of software design tools. The first stage of the study involved an empirical investigation in the form of a case study of the use of standard CAD tool sets and the development of a systems engineering software support tool. It was found that there were several ways in which CAD influenced the creative process, including enhancing visualisation and communication, premature fixation, circumscribed thinking and bounded ideation. The tool development experience uncovered the difficulty in supporting creative processes from the developer's perspective. The issues were the necessity of making assumptions, achieving a balance between structure and flexibility, and the pitfalls of satisfying user wants and needs. The second part of the study involved the development of a model of the creative problem solving process in engineering design. This provided a possible explanation for why purpose designed engineering software tools might encourage an analytical problem solving approach and discourage a more creative approach.

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Poly(ε-caprolactone) (PCL) fibers produced by wet spinning from solutions in acetone under low-shear (gravity-flow) conditions resulted in fiber strength of 8 MPa and stiffness of 0.08 Gpa. Cold drawing to an extension of 500% resulted in an increase in fiber strength to 43 MPa and stiffness to 0.3 GPa. The growth rate of human umbilical vein endothelial cells (HUVECs) (seeded at a density of 5 × 104 cells/mL) on as-spun fibers was consistently lower than that measured on tissue culture plastic (TCP) beyond day 2. Cell proliferation was similar on gelatin-coated fibers and TCP over 7 days and higher by a factor of 1.9 on 500% cold-drawn PCL fibers relative to TCP up to 4 days. Cell growth on PCL fibers exceeded that on Dacron monofilament by at least a factor of 3.7 at 9 days. Scanning electron microscopy revealed formation of a cell layer on samples of cold-drawn and gelatin-coated fibers after 24 hours in culture. Similar levels of ICAM-1 expression by HUVECs attached to PCL fibers and TCP were measured using RT-PCR and flow cytometry, indicative of low levels of immune activation. Retention of a specific function of HUVECs attached to PCL fibers was demonstrated by measuring their immune response to lipopolysaccharide. Levels of ICAM-1 expression increased by approximately 11% in cells attached to PCL fibers and TCP. The high fiber compliance, favorable endothelial cell proliferation rates, and retention of an important immune response of attached HUVECS support the use of gravity spun PCL fibers for three-dimensional scaffold production in vascular tissue engineering. © Mary Ann Liebert, Inc.

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A wire drive pulse echo method of measuring the spectrum of solid bodies described. Using an 's' plane representation, a general analysis of the transient response of such solids has been carried out. This was used for the study of the stepped amplitude transient of high order modes of disks and for the case where there are two adjacent resonant frequencies. The techniques developed have been applied to the measurenent of the elasticities of refractory materials at high temperatures. In the experimental study of the high order in-plane resonances of thin disks it was found that the energy travelled at the edge of the disk and this initiated the work on one dimensional Rayleigh waves.Their properties were established for the straight edge condition by following an analysis similar to that of the two dimensional case. Experiments were then carried out on the velocity dispersion of various circuits including the disk and a hole in a large plate - the negative curvature condition.Theoretical analysis established the phase and group velocities for these cases and experimental tests on aluminium and glass gave good agreement with theory. At high frequencies all velocities approach that of the one dimensional Rayleigh waves. When applied to crack detection it was observed that a signal burst travelling round a disk showed an anomalous amplitude effect. In certain cases the signal which travelled the greater distance had the greater amplitude.An experiment was designed to investigate the phenanenon and it was established that the energy travelled in two nodes with different velocities.It was found by analysis that as well as the Rayleigh surface wave on the edge, a seoond node travelling at about the shear velocity was excited and the calculated results gave reasonable agreement with the experiments.

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An experimental and theoretical study of the impact behaviour of charged microparticles in a high voltage vacuum gap has been carried out to investigate under controlled conditions the role of low velocity microparticles (ζ 500 ms-1) in initiating electrical breakdown in such gaps. This has involved developing a unique (UHV) low-velocity source of micron-sized charged particles to study the underlying mechanical and electrical aspects of micro-particle impact on a range of target materials e.g. Pb, Ti, C, stainless-steel and mica etc., having atomically clean or oxidised surfaces. Argon-ion etching and electron-beam heating has been used for in-situ surface treatment and ellipsometry for characterising the target surfaces. An associated sphere/plane theoretical model has been developed for detailed analysis of the many complex electrical (in-flight in-field emission, M.I.M. tunnelling and ohmic conduction) and mechanical (impact dynamics, deformation and heating) phenomena that are involved when a microparticle closely approaches and impacts on a plane target. In each instance the influence of parameters such as particle radius, particle/target impact velocity, surface field, surface condition and material has been determined.

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The thesis is divided into four chapters. They are: introduction, experimental, results and discussion about the free ligands and results and discussion about the complexes. The First Chapter, the introductory chapter, is a general introduction to the study of solid state reactions. The Second Chapter is devoted to the materials and experimental methods that have been used for carrying out tile experiments. TIle Third Chapter is concerned with the characterisations of free ligands (Picolinic acid, nicotinic acid, and isonicotinic acid) by using elemental analysis, IR spectra, X-ray diffraction, and mass spectra. Additionally, the thermal behaviour of free ligands in air has been studied by means of thermogravimetry (TG), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC) measurements. The behaviour of thermal decomposition of the three free ligands was not identical Finally, a computer program has been used for kinetic evaluation of non-isothermal differential scanning calorimetry data according to a composite and single heating rate methods in comparison with the methods due to Ozawa and Kissinger methods. The most probable reaction mechanism for the free ligands was the Avrami-Erofeev equation (A) that described the solid-state nucleation-growth mechanism. The activation parameters of the decomposition reaction for free ligands were calculated and the results of different methods of data analysis were compared and discussed. The Fourth Chapter, the final chapter, deals with the preparation of cobalt, nickel, and copper with mono-pyridine carboxylic acids in aqueous solution. The prepared complexes have been characterised by analyses, IR spectra, X-ray diffraction, magnetic moments, and electronic spectra. The stoichiometry of these compounds was ML2x(H20), (where M = metal ion, L = organic ligand and x = water molecule). The environments of cobalt, nickel, and copper nicotinates and the environments of cobalt and nickel picolinates were octahedral, whereas the environment of copper picolinate [Cu(PA)2] was tetragonal. However, the environments of cobalt, nickel, and copper isonicotinates were polymeric octahedral structures. The morphological changes that occurred throughout the decomposition were followed by SEM observation. TG, DTG, and DSC measurements have studied the thermal behaviour of the prepared complexes in air. During the degradation processes of the hydrated complexes, the crystallisation water molecules were lost in one or two steps. This was also followed by loss of organic ligands and the metal oxides remained. Comparison between the DTG temperatures of the first and second steps of the dehydration suggested that the water of crystallisation was more strongly bonded with anion in Ni(II) complexes than in the complexes of Co(II) and Cu(II). The intermediate products of decomposition were not identified. The most probable reaction mechanism for the prepared complexes was also Avrami-Erofeev equation (A) characteristic of solid-state nucleation-growth mechanism. The tempemture dependence of conductivity using direct current was determined for cobalt, nickel, Cl.nd copper isonicotinates. An activation energy (ΔΕ), the activation energy (ΔΕ ) were calculated.The ternperature and frequency dependence of conductivity, the frequency dependence of dielectric constant, and the dielectric loss for nickel isonicotinate were determined by using altemating current. The value of s paralneter and the value of'density of state [N(Ef)] were calculated. Keyword Thermal decomposition, kinetic, electrical conduclion, pyridine rnono~ carboxylic acid, cOlnplex, transition metal compJex.

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A novel metathesis catalyst for the polymerisation of acetylene has been developed. The polyacetylene produced by this new catalyst has been characterised by infra-red and NMR spectroscopy. The conductivity of the pristine material has been studied as a function of temperature, pressure and frequency. The effect on the conductivity of doping the material has also been investigated. The new metathesis catalyst has been incorporated into an anionic-to-metathesis transformation reaction. This novel reaction has been used to prepare samples of poly(styrene-co-acetylene). The copolymer has been characterised using U.V./Visible, NMR, infra-red spectroscopy and the surface morphology looked at using scanning electron microscopy. GPC was also used to give some idea of the molecular weights of the materials prepared. The conductivity of the copolymer has been studied as a function of temperature, pressure and frequency. The effect of doping on the conductivity the material has also been investigated. The conductivity results obtained from both materials have been used to try and gain an insight into the mechanism of the conduction processes occurring within the materials. An attempt has also been made to synthesise polyacetylene oligomers (polyenes) by modifying the Ziegler/Natta type catalysts commonly used to synthesise polyacetylene. The polyenes were characterised using U.V./Visible and infra-red spectroscopy together with GPC and GCMS.

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Fully dense graphene nanosheet(GNS)/Al2O3 composites with homogeneously distributed GNSs of thicknesses ranging from 2.5 to 20 nm have been fabricated from ball milled expanded graphite and Al2O3 by spark plasma sintering. The percolation threshold of electrical conductivity of the as-prepared GNS/Al2O3 composites is around 3 vol.%, and this new composite outperforms most of carbon nanotube/Al2O3 composites in electrical conductivity. The temperature dependence of electrical conductivity indicated that the as-prepared composites behaved as a semimetal in a temperature range from 2 to 300 K.

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The Models@run.time (MRT) workshop series offers a discussion forum for the rising need to leverage modeling techniques for the software of the future. The main goals are to explore the benefits of models@run.time and to foster collaboration and cross-fertilization between different research communities like for example like model-driven engineering (e.g. MODELS), self-adaptive/autonomous systems communities (e.g., SEAMS and ICAC), the control theory community and the artificial intelligence community. © 2012 Authors.

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Whether distance learning spells the end of traditional campuses, as some maintain, or whether distance learning instead represents a powerful addition to a growing array of delivery options for higher education, its impact on higher education is great and growing. Distance learning is creating alternative models of teaching and learning, new job descriptions for faculty, and new types of higher education providers. The advent of Distance and Distributed Learning has raised numerous questions about quality and quality assurance: ² How do established distance learning institutions ensure quality? ² What more needs to be done? ² How do quality assurance agencies view the distinction between on- and off-campus teaching and learning? This talk discusses these issues from the viewpoints of funding organisa- tion, quality assurance agencies and the learners.

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Purpose – This paper aims to investigate the manner in which technological innovation in the European electrical-grid sector has developed by focusing, in particular, on the effect of public policy on innovation. To achieve this aim, this paper highlights how technological innovation and development progressed from the 1960s to the 1980s, and contrasts this period with the deregulated/privatization environment. Design/methodology/approach – The paper is based on a series of in-depth multiple company case studies of grid companies, some of their suppliers and other actors in their broader business network. Empirical data were collected through 55 interviews. Findings – The authors find that a phase of mutual collaboration was encouraged in the first period, which led to strong technological innovation with a focus on product quality and the development of functionality. Buyers played a pivotal role in the development of products and posed technical requirements. In contrast, the current role of the buyer has transformed principally into one of evaluating competing bids for specific projects. Today, buyers face increasing pressure to substantially lower CO2 emissions and transform the energy grid system. These goals are difficult to achieve without a new way of thinking about innovation. Research limitations/implications – Models to achieve innovation must not only focus on individual research projects; instead, the innovation should be factored into normal business dealings in the supply chain. Practical implications – We propose that policymakers and regulators need to: accommodate for innovation and address the collaborative elements of innovation when developing policies and regulations. Furthermore, regulators have the option of either developing a strategic vision for the electrical-grid network or incorporating sustainability into the evaluation of electrical grids and, thus, consumers’ willingness to pay. Originality/value – This paper makes a distinctive contribution in the area of innovation for electrical grids. Our paper shows how innovation and the development of new technology for electrical grids changed over time. Furthermore, this paper describes the energy sector in terms of a business network comprising the different actors involved in innovation and development and, thus, their role in the energy supply chain.

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We show that optical and electrical phase conjugation enable effective nonlinear compensation, The impact of polarization mode dispersion and finite processing bandwidth on the ultimate limits are also considered.