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Record W2290824782 · doi:10.14288/1.0058980

Electrostatic charging in gas-solid fluidized beds

2009· article· en· W2290824782 on OpenAlexaff
Ah‐Hyung Alissa Park

Bibliographic record

VenuecIRcle (University of British Columbia) · 2009
Typearticle
Languageen
FieldEngineering
TopicMineral Processing and Grinding
Canadian institutionsUniversity of British Columbia
Fundersnot available
KeywordsMaterials science

Abstract

fetched live from OpenAlex

Electrostatic charges in fluidized beds, generated through various mechanisms such as triboelectrification, ion collection, thermionic emission, and frictional charging, can cause particle agglomeration and hazardous electrical discharges. In this study, electrostatic charging in gas-solid fluidized beds was investigated by means of a simplified mechanistic model and bubble injection and free bubbling experiments in twodimensional and three-dimensional fluidized beds. An electrostatic ball probe measured static charges in fluidized beds, while an optical fiber probe was used to determine the simultaneous movement of the bubbles. Preliminary experiments indicated that a negatively charged object results in a negative voltage peak followed by a positive voltage peak. The opposite pattern occurred for a positively charged object. The current calculated from the voltage output was integrated to estimate the charge induced and transferred. It was shown that the voltage signal can be considered to consist of two components: induced voltage and that due to the direct charge transfer between charged particles and the probe. A simplified model was also developed by applying the method of images to distinguish induced and transferred charges. Spherical bubbles surrounded by a monolayer of charged particles and a medium of dielectric constant 1 were assumed in the models. Bubble injection experiments in a 2-D bed showed that both 321 pm glass beads and 378 pm polyethylene particles were charged positively, while 318 urn polyethylene particles were charged negatively. As bubble size increased the charge induced and transferred increased accordingly. The model gave reasonable predictions of the charge output. Increasing the relative humidity of the fluidizing air between 60% and 80% reduced the electrostatic charge accumulation by increasing the surface conductivity, enhancing the rate of charge dissipation. Adding group C fines and Larostat 519 reduced or eliminated particle buildup on the inner wall of the fluidization column, but the former probably also affected other interparticle forces such as Van der Waals forces and altered the fluidization behaviour. 1 wt% Larostat 519 clearly reduced electrostatic charge accumulation during free bubbling in a 3-D bed of 318 urn polyethylene particles; within 1.5 hr charge accumulation decreased to an insignificant level.

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)0.001
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 score0.004
Threshold uncertainty score0.008

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.001
Open science0.0010.000
Research integrity0.0010.000
Insufficient payload (model declined to judge)0.0000.000

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 head0.005
GPT teacher head0.170
Teacher spread0.165 · 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

Citations31
Published2009
Admission routes1
Has abstractyes

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