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Vacuum Brazing of Carbon Nanotube Strands

2009· dissertation· en· W2681154 on OpenAlexfundno aff
Wei Wu

Bibliographic record

VenueMasters Thesis · 2009
Typedissertation
Languageen
FieldMaterials Science
TopicCarbon Nanotubes in Composites
Canadian institutionsnot available
FundersUniversity of Waterloo
KeywordsBrazingCarbon nanotubeMaterials scienceNanotechnologyNanotubeCarbon fibersComposite materialAlloyComposite number

Abstract

fetched live from OpenAlex

Carbon nanotubes (CNTs) discovered at 1991 have attracted great interest for applications in Nano-Electro-Mechanical-Systems (NEMS). However, the search for methods to join CNTs with metallic parts has been a worldwide challenge. Many efforts have been devoted to manipulating individual CNTs and joining them to each other. Joining processes so far attempted are premature and fall short of efficiency for joint quality evaluation. Thus, it has been found necessary to work on macro CNTs strands which are easy to handle via macro joining techniques. In this study, vacuum brazing technology has been developed for joining macro CNTs strands with Ni using a Ti-Ag-Cu alloy. The brazing mechanism has been confirmed as due to TiC formation at the CNTs/Ti-Ag-Cu interface. \n To evaluate this novel vacuum brazing technique for CNTs joining, the temperature effect on the brazing mechanism, microstructure and stoichiometry at joint interface needed to be understood. Firstly, the influence of temperature (from room temperature to 1000C) on mechanical behaviour of CNTs was well examined. The ultimate tensile strength (UTS) of CNTs was measured to be a maximum at 900C. \nThen, the mechanical performance of the joints was investigated from 850C to 1000C, and the fracture modes of the joints were identified. The UTS of joint also achieves maximum at 900C. Below 900C, due to little TiC formation, the bonding is weak thus leading to interfacial fracture. Above 900C, due to much TiC formation, the bonding is strong thus resulting in CNTs fracture. \n Furthermore, the vacuum brazing technique was applied to join CNTs to Ni contact wires used as a lamp filament. Compared to the filament joined by Ag paste or mechanical connection, the illumination of the brazed CNTs filament was stronger. The current density of the brazed filament was superior to the Ag paste connected filament. This may represent a promising way to produce energy saving lamps.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.003
Threshold uncertainty score0.010

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0030.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.009
GPT teacher head0.240
Teacher spread0.231 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2009
Admission routes1
Has abstractyes

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