24,500 research outputs found

    Thermal And Flow Analysis Of Piezoelectric Fans For Cooling LEDS Packages

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    Computers, LED packages and portable electronic devices, such as minilaptops, tablets, and cellular phones, are rapidly emerging in lighter, slimmer, and more compact forms with high functionalities to meet consumer demands. This tremendous growth in advance electronics necessitates modern solutions to be adapted with the new challenges of thermal management. One of the recent thermal solutions is piezoelectric fans, which recently considered as a very strong candidate for cooling the next generation in general microelectronic devices. Komputer, pakej LED dan alatan elektronik mudah-alih, seperti komputer riba mini, tablet, telefon sel, meningkat dengan ketara dari segi bentuk, ringan, nipis, dan lebih padat dengan fungsi yang tinggi bagi memenuhi permintaan pelangan. Pertumbuhan yang ketara ini dalam elektronik termaju memerlukan penyelesaian moden bagi menyesuaikan dengan cabaran baru pengurusan terma. Salah satu daripada penyelesaian terma terbaru adalah kipas piezoelektrik, yang mana baru-baru ini dianggap sebagai alat yang amat sesuai bagi penyejukan generasi hadapan dalam alatan mikroelektronik umum

    On the Deployment of Healthcare Applications over Fog Computing Infrastructure

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    Fog computing is considered as the most promising enhancement of the traditional cloud computing paradigm in order to handle potential issues introduced by the emerging Interned of Things (IoT) framework at the network edge. The heterogeneous nature, the extensive distribution and the hefty number of deployed IoT nodes will disrupt existing functional models, creating confusion. However, IoT will facilitate the rise of new applications, with automated healthcare monitoring platforms being amongst them. This paper presents the pillars of design for such applications, along with the evaluation of a working prototype that collects ECG traces from a tailor-made device and utilizes the patient's smartphone as a Fog gateway for securely sharing them to other authorized entities. This prototype will allow patients to share information to their physicians, monitor their health status independently and notify the authorities rapidly in emergency situations. Historical data will also be available for further analysis, towards identifying patterns that may improve medical diagnoses in the foreseeable future

    Urban and extra-urban hybrid vehicles: a technological review

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    Pollution derived from transportation systems is a worldwide, timelier issue than ever. The abatement actions of harmful substances in the air are on the agenda and they are necessary today to safeguard our welfare and that of the planet. Environmental pollution in large cities is approximately 20% due to the transportation system. In addition, private traffic contributes greatly to city pollution. Further, “vehicle operating life” is most often exceeded and vehicle emissions do not comply with European antipollution standards. It becomes mandatory to find a solution that respects the environment and, realize an appropriate transportation service to the customers. New technologies related to hybrid –electric engines are making great strides in reducing emissions, and the funds allocated by public authorities should be addressed. In addition, the use (implementation) of new technologies is also convenient from an economic point of view. In fact, by implementing the use of hybrid vehicles, fuel consumption can be reduced. The different hybrid configurations presented refer to such a series architecture, developed by the researchers and Research and Development groups. Regarding energy flows, different strategy logic or vehicle management units have been illustrated. Various configurations and vehicles were studied by simulating different driving cycles, both European approval and homologation and customer ones (typically municipal and university). The simulations have provided guidance on the optimal proposed configuration and information on the component to be used

    Statistical Power Supply Dynamic Noise Prediction in Hierarchical Power Grid and Package Networks

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    One of the most crucial high performance systems-on-chip design challenge is to front their power supply noise sufferance due to high frequencies, huge number of functional blocks and technology scaling down. Marking a difference from traditional post physical-design static voltage drop analysis, /a priori dynamic voltage drop/evaluation is the focus of this work. It takes into account transient currents and on-chip and package /RLC/ parasitics while exploring the power grid design solution space: Design countermeasures can be thus early defined and long post physical-design verification cycles can be shortened. As shown by an extensive set of results, a carefully extracted and modular grid library assures realistic evaluation of parasitics impact on noise and facilitates the power network construction; furthermore statistical analysis guarantees a correct current envelope evaluation and Spice simulations endorse reliable result

    Thermosonic flip chip interconnection using electroplated copper column arrays

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    Printed Circuit Board (PCB) design process and fabrication

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    This module describes main characteristics of Printed Circuit Boards (PCBs). A brief history of PCBs is introduced in the first chapter. Then, the design processes and the fabrication of PCBs are addressed and finally a study case is presented in the last chapter of the module.Peer ReviewedPostprint (published version

    The Role of Density Functional Theory Methods in the Prediction of Nanostructured Gas-Adsorbent Materials

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    With the advent of new synthesis and large-scale production technologies, nanostructured gas-adsorbent materials (GAM) like carbon nanocomposites and metal-organic frameworks are becoming increasingly more influential in our everyday lives. First-principles methods based on density functional theory (DFT) have been pivotal in establishing the rational design of GAM, a factor which has tremendously boosted their development. However, DFT methods are not perfect and due to the stringent accuracy thresholds demanded in modelling of GAM (i.e., exact binding energies to within ~0.01 eV) these techniques may provide erroneous conclusions in some challenging situations. Examples of problematic circumstances include gas-adsorption processes in which both electronic long-range exchange and nonlocal correlations are important, and systems where many-body energy and Coulomb screening effects cannot be disregarded. In this critical review, we analyse recent efforts done in the assessment of the performance of DFT methods in the prediction and understanding of GAM. Our inquiry is constrained to the areas of hydrogen storage and carbon capture and sequestration, for which we expose a number of unresolved modelling controversies and define a set of best practice simulation principles. Also, we identify the subtle problems found in the generalization of DFT benchmark studies performed in model cluster systems to real materials, and discuss effective approaches to circumvent them. The increasing awareness of the strengths and imperfections of DFT methods in the simulation of gas-adsorption phenomena should lead in the medium term to more precise, and hence even more fruitful, ab initio engineering of GAM.Comment: 27 pages, 10 figures, review articl

    Mapping customer needs to engineering characteristics: an aerospace perspective for conceptual design

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    Designing complex engineering systems, such as an aircraft or an aero-engine, is immensely challenging. Formal Systems Engineering (SE) practices are widely used in the aerospace industry throughout the overall design process to minimise the overall design effort, corrective re-work, and ultimately overall development and manufacturing costs. Incorporating the needs and requirements from customers and other stakeholders into the conceptual and early design process is vital for the success and viability of any development programme. This paper presents a formal methodology, the Value-Driven Design (VDD) methodology that has been developed for collaborative and iterative use in the Extended Enterprise (EE) within the aerospace industry, and that has been applied using the Concept Design Analysis (CODA) method to map captured Customer Needs (CNs) into Engineering Characteristics (ECs) and to model an overall ‘design merit’ metric to be used in design assessments, sensitivity analyses, and engineering design optimisation studies. Two different case studies with increasing complexity are presented to elucidate the application areas of the CODA method in the context of the VDD methodology for the EE within the aerospace secto

    Kaedah pembelajaran lukisan kejuruteraan berasaskan simulasi

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    Kajian yang dijalankan ini adalah untuk melihat kebolehgunaan sebuah perisian pendidikan yang menerapkan Kaedah Pembelajaran Lukisan Kejuruteraan Berasaskan Simulasi bagi menyelesaikan masalah kurang faham , kurang minat dan kebergantungan yang terlalu memusat kepada guru di kalangan pelajar Tingkatan 4, Sekolah Menengah Ungku Aziz, Sabak Bernam, Selangor . Justeru, penyampaian isi kandungan yang bersesuaian dengan tahap pemikiran atau kognitif pelajar, aspek minat dan motivasi serta pembelajaran ala akses kendiri dirasakan sebagai faktor utama yang ingin dikenal pasti dalam perisian yang dibangunkan bagi menyelesaikan masalah tersebut. Macromedia Authorware versi 6.5 dipilih sebagai bahasa pengarangan bagi membangunkan perisian pendidikan ini. Seramai 30 responden dipilih untuk mendapatkan maklum balas terhadap kajian ini. Data yang didapati telah dianalisis menggunakan perisian Statistical Package for Social Science (SPSS) versi 11.0 menggunakan kaedah deskriptif min. Hasil kajian mendapati bahawa maklum balas adalah positif terhadap faktor-faktor yang telah dikaji
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