5,339 research outputs found

    Demonstration of fine pitch FCOB (Flip Chip on Board) assembly based on solder bumps at Fermilab

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    Bump bonding is a superior assembly alternative compared to conventional wire bond techniques. It offers a highly reliable connection with greatly reduced parasitic properties. The Flip Chip on Board (FCOB) procedure is an especially attractive packaging method for applications requiring a large number of connections at moderate pitch. This paper reports on the successful demonstration of FCOB assembly based on solder bumps down to 250um pitch using a SUESS MA8 flip chip bonder at Fermilab. The assembly procedure will be described, microscopic cross sections of the connections are shown, and first measurements on the contact resistance are presented.Comment: 4 pages, 8 figure

    Viability of Rice Husk Ash Concrete Brick/Block from Green Electricity in Bangladesh

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    As a developing country, Bangladesh has to face numerous challenges. Self Independence in electricity, contributing to climate change by reducing carbon emission and bringing the backward population of society to the mainstream is more challenging for them. Therefore, it is essential to ensure recycled use of local products to the maximum level in every sector. Some private organizations have already worked alongside government to bring the backward population to the mainstream by developing their financial capacities. As rice husk is the largest single category of the total energy supply in Bangladesh. As part of this strategy, rice husk can play a great as a promising renewable energy source, which is readily available, has considerable environmental benefits and can produce electricity and ensure multiple uses of byproducts in construction technology. For the first time in Bangladesh, an experimental multidimensional project depending on Rice Husk Electricity and Rice Husk Ash (RHA) concrete brick/block under Green Eco-Tech Limited has already been started. Project analysis, opportunity, sustainability, the high monitoring component, limitations and finally evaluated data reflecting the viability of establishing more projects using rice husk are discussed in this paper. The by-product of rice husk from the production of green electricity, RHA, can be used for making, in particular, RHA concrete brick/block in Bangladeshi aspects is also discussed here

    The diagnosis of Poncet\u27s disease

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    Two cases of polyarthritis in young people with extra-articular tuberculosis are described. The clinical features were consistent with the concept of Poncet\u27s disease. After synovial biopsy one patient proved to have tuberculous peripheral arthritis. This observation raised doubts about the diagnosis in the other patient. Multiple joints may be simultaneously infected with Mycobacterium tuberculosis and Poncet\u27s disease, if it exists, should not be entertained in the absence of synovial biopsy

    Use of multilayer feedforward neural networks in identification and control of Wiener model

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    Includes bibliographical references (page 258).The problem of identification and control of a Wiener model is studied. The proposed identification model uses a hybrid model consisting of a linear autoregressive moving average model in cascade with a multilayer feed forward neural network. A two-step procedure is proposed to estimate the linear and nonlinear parts separately. Control of the Wiener model can be achieved by inserting the inverse of the static nonlinearity in the appropriate loop locations. Simulation results illustrate the performance of the proposed method

    Sustaining traditional food: consumers' perceptions on physical characteristics of keropok lekor or fish snack

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    Keropok Lekor or frankfurter-like snack has long existed in Malaysia and has been sold in commercial retail shops as well as on the streets. The aims of this study were to analyze consumer's perception and attitude towards keropok lekor and to determine consumer's behavior on the product. Survey questionnaire was employed as a data collection tool. A total of 212 respondents from a university participated in this study. Results showed that more than 70% of the respondents chose to eat keropok lekor because of the taste. Half of the respondents chose black pepper as an innovative supplementary flavor of keropok lekor. This study also explores and analyses preliminary consumer behavior about keropok lekor such as satisfaction level, factors that drive consumption, product's image from consumer perspectives and etc

    Axial load-axial deformation behaviour of circular concrete columns reinforced with GFRP bars and helices

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    Fibre Reinforced Polymer (FRP) bars has attracted a significant amount of research attention in the last three decades to overcome the problems associated with the corrosion of steel reinforcing bars in reinforced concrete members. A limited number of studies, however, have investigated the behaviour of concrete columns reinforced with FRP bars. Also, available design standards either ignore the contribution of or do not recommend the use of GFRP bars in compression members. This study reports the results of experimental investigations of concrete specimens reinforced with GFRP bars and GFRP helices as longitudinal and transverse reinforcement, respectively. A total of five circular concrete columns of 205 mm in diameter and 800 mm in height were cast and tested under axial compression. The experimental results showed that reducing the spacing of the GFRP helices or confining the specimens with CFRP sheet led to improvements in the strength and ductility of the specimens. Also, an analytical model has been developed for the axial load-axial deformation behaviour of the circular concrete columns reinforced with GFRP bars and helices. The model has been validated with the experimental results

    A roadmap to develop dementia research capacity and capability in Pakistan: a model for low- and middle-income countries

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    Objective To produce a strategic roadmap for supporting the development of dementia research in Pakistan. Background While global research strategies for dementia research already exist, none is tailored to the specific needs and challenges of low- and middle-income countries (LMIC) like Pakistan. Methods We undertook an iterative consensus process with lay and professional experts to develop a Theory of Change-based strategy for dementia research in Pakistan. This included Expert Reference Groups (ERGs), strategic planning techniques, a “research question” priority survey, and consultations with Key Opinion Leaders. Results We agreed on ten principles to guide dementia research in Pakistan, emphasizing pragmatic, resource sparing, real-world approaches to support people with dementia, both locally and internationally. Goals included capacity/capability building. Priority research topics included raising awareness and understanding of dementia, and improving quality of life. Conclusion This roadmap may be a model for other LMIC health ecosystems with emerging dementia research cultures

    Optical properties of diamond like carbon films prepared by DC-PECVD

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    Diamond-like carbon (DLC) thin films were deposited at different substrate temperatures using methane and hydrogen gas in DC-PECVD at 2x10-1Torr. From the light transmission using UV-VIS spectroscopy it was found that the optical transition had changed from allowed indirect transition to allowed direct transition as the substrate temperature increased. The Optical gap increased with temperature, highest of 3.034 eV was observed at 573 K, beyond which it dropped. Colour of the film changed from light brownish to a colourless transparent film in the higher temperature. The Urbach energy decreased from 1.25 eV to 0.75 eV with increasing substrate temperature till 573 K and a slight increase after it. This trend is attributed to change in sp3/sp2 ratio or change in structure. The cluster size decreases with temperature, resulting in larger band gap and the structure more ordered. Similar pattern is also witnessed in the emission spectrum of the photoluminescence

    Gill net selectivity for European hake Merluccius merluccius from southern Portugal: implications for fishery management

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    A study of European hake Merluccius merluccius gill net selectivity was undertaken off the Algarve (Southern Portugal), between 1999 and 2001. Four nominal mesh sizes (70, 80, 90 and 100 mm) were used in fishing trials and the 'share each length class catch total' (SELECT) method was used to fit gill net selectivity curves. Hake were caught in the same size range by all mesh sizes, between 17 and 65 cm total length. While most fishes were wedged, significant and similar proportions were entangled in all mesh sizes, contributing to the wide size range, and in some cases, bimodal shape of catch size frequency distributions. Insignificant numbers of undersized hake were caught, with most catches consisting of mature female fish. Catch rates decreased sharply with increasing mesh size. The bimodal model gave the best fit for hake that were wedged, with estimated modal lengths of 40.1, 46.7 and 51.0 cm for the 70, 80 and 90 mm nominal mesh sizes, respectively. The high catch per unit effort of the smallest mesh size, with most fish caught being female, together with the fact that the modal length of the fitted selectivity curve is well below the size at maturity for hake in Portuguese waters, suggests that the 80 mm nominal mesh size is more appropriate for ensuring resource sustainability
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