1,354,302 research outputs found
DEBOND ON DEMAND ADHESIVES USING THE FLAME- RETARDANCY CONCEPT
No full textSince their emergence in the early twentieth century, adhesive technologies have largely supplanted traditional joining methods such as screws and rivets due to their superior mechanical properties. This advancement enabled the integration of diverse materials, creating composite materials that allow for more compact, lighter, and better-sealed structures, with enhanced resistance to environmental factors. These improvements have significantly affected energy consumption, carbon footprint, and production costs, particularly in transportation.
Despite these advantages, adhesive technologies face a key challenge: the permanence of the bond, which limits reuse and recycling, leading to increased waste and material downgrading. To address this, reversible or debondable adhesives have been developed, which allow component disassembly and reuse of the material at their original value. Various debonding technologies, from van der Waals-based adhesives to those that respond to electrical currents, have been explored, yet no universal solution has emerged, especially for structural bonding that balances ease of implementation and mechanical integrity of adhesively bonded joints.
This thesis introduces a novel debonding solution inspired by flame retardancy. We repurpose flame retardants, exploiting their ability to swell under heat stimuli to induce debonding. The study examines several flame-retardant systems Ammonium Polyphosphate (APP) in two different forms, Melamine Polyphosphate (MPP), Organophosphorus Flame Retardants (PCO 900), and Expandable Graphite (EG) and their effects on the mechanical properties of bonded structures, both pre- and post-debonding.
In parallel with the mechanical study, each system is characterized and thoroughly investigated to provide a comprehensive understanding of the chemistry behind the debonding mechanisms, extending beyond traditional mechanical studies commonly found in the literature. Although this work focuses primarily on adhesively bonded joints, the final chapter extends these technologies to composite structures, such as sandwich structures, marking the initial steps toward broader application of this debond-on-demand technology.FR4RECYCLIN
Low Power Instrumentation Amplifier for a Fully Implantable Neural Recording System
No full textRecording neural signal from a living human body is a complex
task and it is an important research issues for neuroscientists and
researchers in biomedical engineering. The major issue to over-
come in the design of a system that is aimed at being implant
into the human body is having a low power consumption, low
noise circuit and small dimension to minimize tissue damage. In
this paper, specific issues of the most important part of such a
neural acquisition system are presented; in particular, the design
of a low-power amplifier, for a fully implantable neural recording
system, is described. The amplifier uses a differential pair as
input stage. Given that neural amplifiers must include differen-
tial input pair to achieve a high common-mode ratio rejection
(CMRR). The amplifier has been designed in the AMS 0.35 μm
standard CMOS process. The amplifier current consumption is
4.61 μA at ±1V supply, which gives a power consumption of
9.22 μW. The low cutoff frequency is adjustable from 21 Hz to
100 Hz, with four tunable gains of 43.6 dB, 48 dB, 50 dB and 52.8
dB. The upper cutoff frequency is about 7.6 kHz. The CMRR is
113 dB and the power supply ratio rejection is PSRR > 73dB.
The input referred noise is 14.8 μV rms over 100 10 kHz. The
amplifier gives an input DC offset of 196 μV
Low Power Instrumentation Amplifier for a Fully Implantable Neural Recording System
No full textRecording neural signal from a living human body is a complex
task and it is an important research issues for neuroscientists and
researchers in biomedical engineering. The major issue to over-
come in the design of a system that is aimed at being implant
into the human body is having a low power consumption, low
noise circuit and small dimension to minimize tissue damage. In
this paper, specific issues of the most important part of such a
neural acquisition system are presented; in particular, the design
of a low-power amplifier, for a fully implantable neural recording
system, is described. The amplifier uses a differential pair as
input stage. Given that neural amplifiers must include differen-
tial input pair to achieve a high common-mode ratio rejection
(CMRR).
Extracting Electric Power From Human Body For Supplying Neural Recording System
No full textA powerful approach to the characterization of cellular electrical activity is electrical recording from cells or living tissues. The human central and / or peripheral nervous system has been a subject of study and fascination of the neuroscience and biomedical engineering communities for many decades. In this paper, we propose a new approach to feed implantable neural recording system, which based on extracting electrical power from human tissue warmth in order to supply a biomedical neural recording system. The major issue to overcome, in the design of a system that is aimed at being implant into the human body, is having a low power consumption, low noise circuit and small dimension to minimize tissue damage
Extracting Electric Power From Human Body For Supplying Neural Recording System
No full textA powerful approach to the characterization of cellular electrical activity is electrical recording from cells or living tissues. The human central and / or peripheral nervous system has been a subject of study and fascination of
the neuroscience and biomedical engineering communities for many decades. In this paper, we propose a new approach to feed implantable neural recording system, which based on extracting electrical power from uman tissue warmth in order to supply a biomedical neural recording system. The major issue to overcome, in the design of a system that is aimed at being implant into the human body, is having a low power consumption, low
noise circuit and small dimension to minimize tissue damage
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
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