559 research outputs found

    12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

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    Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin

    Electro-stimulating implants for bone regeneration: parameter analysis and design optimization

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    This thesis investigated a bipolar induction screw system with an integrated coil for bone electrical stimulation. The aim was to analyse the influence of the stimulation parameters and electro-stimulating implants parameters on bone regeneration and carry out a parameter optimization for bone electrical stimulation. Finite element analysis was used to calculate the electric field distributions in the bone. The results showed that the screw’s z-direction positioning (moving in and out of femoral head) yields the highest effect on the volume tissue activated in patient’s femoral head model

    Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

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    Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

    Biologically inspired transparent material as an energy system

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    Glazed envelopes on buildings play a major role in operational energy consumptionas they define the boundary conditions between the climate outside and the thermalcomfort inside a building. Glass façades are viewed as an uncontrolled load that setsthe operational performance requirements for air-cooling mechanical systems. Thesefaçades are determined by code compliant performance levels set by a singleprescriptive static, the U value. This is energetically weak, a dynamic IR absorberstrategy is needed, since performance requires change by the hour, season, andweather conditions to sync with a warming earth atmosphere. A transparent dynamicIR absorber , will be modulated by temperature-dependance of the absorber by activetailored flows in a microfluidic based platform, than conventional IR static absorbers.Nature’s characterization of materials is a thermally dynamic response in real time toa microenvironment. This functionality of heat seeking materials would advance a transparent material by energy capture and storage. The hypothesis demonstratesnature’s use of fluidics to direct the structural assembly of a polymer into a thermallyfunctional device, to actively regulate solar radiation as an IR absorber, to lower thepolymer device phase transition temperature. This research determines thisfunctionality by hierarchical multi micro-channel network scaling, as a leaf resistor. Resistor conduit analysis defines flow target resistance through simulation to generatea multi micro-channel network, for enhanced solar radiation absorption. This isdemonstrated by precise hydrodynamic control in a network using switching of waterflow as a thermal switching medium to regulate heat transport flow. Nature evaluatesheat flow transport in real time that is not emulated in current glass façade staticperformance. The knowledge gap is therefore to advance a transparent material from astatic function, to a dynamic IR absorber for solar modulation, and this isdemonstrated in this research

    Numerical modelling of additive manufacturing process for stainless steel tension testing samples

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    Nowadays additive manufacturing (AM) technologies including 3D printing grow rapidly and they are expected to replace conventional subtractive manufacturing technologies to some extents. During a selective laser melting (SLM) process as one of popular AM technologies for metals, large amount of heats is required to melt metal powders, and this leads to distortions and/or shrinkages of additively manufactured parts. It is useful to predict the 3D printed parts to control unwanted distortions and shrinkages before their 3D printing. This study develops a two-phase numerical modelling and simulation process of AM process for 17-4PH stainless steel and it considers the importance of post-processing and the need for calibration to achieve a high-quality printing at the end. By using this proposed AM modelling and simulation process, optimal process parameters, material properties, and topology can be obtained to ensure a part 3D printed successfully

    Aeronautical engineering: A continuing bibliography (supplement 152)

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    The bibliography lists 338 reports, articles and other documents introduced into the NASA scientific and technical information system in August 1982

    The Active CryoCubeSat Technology: Active Thermal Control for Small Satellites

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    Modern CubeSats and Small Satellites have advanced in capability to tackle science and technology missions that would usually be reserved for more traditional, large satellites. However, this rapid growth in capability is only possible through the fast-to-production, low-cost, and advanced technology approach used by modern small satellite engineers. Advanced technologies in power generation, energy storage, and high-power density electronics have naturally led to a thermal bottleneck, where CubeSats and Small Satellites can generate more power than they can easily reject. The Active CryoCubeSat (ACCS) is an advanced active thermal control technology (ATC) for Small Satellites and CubeSats, which hopes to help solve this thermal problem. The ACCS technology is based on a two-stage design. An integrated miniature cryocooler forms the first stage, and a single-phase mechanically pumped fluid loop heat exchanger the second. The ACCS leverages advanced 3D manufacturing techniques to integrate the ATC directly into the satellite structure, which helps to improve the performance while simultaneously miniaturizing and simplifying the system. The ACCS system can easily be scaled to mission requirements and can control zonal temperature, bulk thermal rejection, and dynamic heat transfer within a satellite structure. The integrated cryocooler supports cryogenic science payloads such as advanced LWIR electro-optical detectors. The ACCS hopes to enable future advanced CubeSat and Small Satellite missions in earth science, heliophysics, and deep space operations. This dissertation will detail the design, development, and testing of the ACCS system technology

    Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

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    This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

    A two-stage structural optimisation and thermal discretisation of non-convective structured insulators: applications in granular-solid structures by additive manufacturing technology

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    A systematic design procedure for characterising the strength and insulation requirements of a modular unit structure from additive manufacturing has been presented. The proposed 'two-stage' method consists of structural optimisation and thermal 'discretisation', through use of the Metamorphic Development (MD) and Discretisation by Partitioning Method (DbPM), respectively. A structural layout optimisation method of a consolidated granular-solid structure for strength requirements is demonstrated. The reliability of the layout optimized design solution tested using experiments and finite element analysis (PEA) are reproduced with reasonable accuracy. Layout optimisation yielded 40% savings in build material, whilst satisfying the targeted deflection. [Continues.
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