The network strength of non-flocculated fibre suspensions

1999 ◽  
Vol 14 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Sven R. Andersson ◽  
Johan Ringnér ◽  
Anders Rasmuson
Keyword(s):  
Fibre Suspensions ◽  
Network Strength

scholarly journals Fines mobility and distribution in streaming fibre networks: experimental evidence and numerical modeling

Cellulose ◽  
2020 ◽  
Vol 27 (16) ◽  
pp. 9663-9682
Author(s):  
Jakob D. Redlinger-Pohn ◽  
Melanie Mayr ◽  
Gregor Schaub ◽  
David Gruber ◽  
Stefan Radl
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Removal Rate ◽  
Small Particles ◽  
Classical View ◽  
Fibre Network ◽  
Fibre Suspensions ◽  
Fibre Suspension ◽  
Network Strength

AbstractThe motion of flocculated fibres in a streaming suspension is governed by the balance of the network strength and hydrodynamic forces. With increasing flow rate through a channel, (1) the network initially occupying all space, (2) is then compressed to the centre, and (3) ultimately dispersed. This classical view neglects fibres-fines: we find that the distribution of these small particles differs in streaming suspensions. While it is known that fibre-fines can escape the fibre network, we find that the distribution of fibre-fines is non-homogenous in the network during compression: fibre-fines can be caged and retarded in the streaming fibre network. Hence, the amount of fibre-fines is reduced outside of a fibre network and enriched at the network’s interface. Aiming on selectively removing fibre-fines from a streaming network by suction, we identify a reduction of the fines removal rate. That documents a hindered mobility of fibre-fines when moving through the network of fibres. Additionally, we found evidence, that the mobility of fibre-fines is dependent on the fibre-fines quality, and is higher for fibrillar fines. Consequently, we suggest that the quality of fibre-fines removed from the suspension can be controlled with the flow regime in the channel. Finally, we present a phenomenological model to compute the length dependent fibre distribution in an arbitary geometry. For a fibre suspension channel flow we are able to predict a length-dependent fibre segregation near the channel’s centre. The erosion of a plug of long fibres was however underestimated by our model. Interestingly, our model with parameters fitted to streaming fibre suspension qualitatively agreed with the motion of micro-fibrillated cellulose. This gives hope that devices for handling flocculated fibre suspensions can be designed in the future with greater confidence.

Profiling Reviewers’ Social Network Strength and Predicting the “Helpfulness” of Online Customer Reviews

2020 ◽  
pp. 101026
Author(s):  
Muhammad Bilal ◽  
Mohsen Marjani ◽  
Ibrahim Abaker Targio Hashem ◽  
Nadia Malik ◽  
Muhammad Ikram Ullah Lali ◽  
...  
Keyword(s):  
Social Network ◽  
Customer Reviews ◽  
Online Customer Reviews ◽  
Network Strength

scholarly journals Specificity of psychopathology across levels of severity: a transdiagnostic network analysis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Robin N. Groen ◽  
Marieke Wichers ◽  
Johanna T. W. Wigman ◽  
Catharina A. Hartman
Keyword(s):  
Diagnostic Interview ◽  
Illness Severity ◽  
Self Report ◽  
Global Network ◽  
Network Approach ◽  
Network Characteristics ◽  
Hyperactivity Disorder ◽  
Symptom Domains ◽  
Network Strength ◽  
Standardized Diagnostic Interview

AbstractA prominent hypothesis within the field of psychiatry is that the manifestation of psychopathology changes from non-specific to specific as illness severity increases. Using a transdiagnostic network approach, we investigated this hypothesis in four independent groups with increasing psychopathology severity. We investigated whether symptom domains became more interrelated and formed more clusters as illness severity increased, using empirical tests for two network characteristics: global network strength and modularity-based community detection. Four severity groups, ranging from subthreshold psychopathology to having received a diagnosis and treatment, were derived with a standardized diagnostic interview conducted at age 18.5 (n = 1933; TRAILS cohort). Symptom domains were assessed using the Adult Self Report (ASR). Pairwise comparisons of the symptom networks across groups showed no difference in global network strength between severity groups. Similar number and type of communities detected in the four groups exceeded the more minor differences across groups. Common clusters consisted of domains associated with attention deficit hyperactivity disorder (ADHD) and combined depression and anxiety domains. Based on the strength of symptom domain associations and symptom clustering using a network approach, we found no support for the hypothesis that the manifestation of psychopathology along the severity continuum changes from non-specific to specific.

Enhanced sludge conditioning by enzyme pre-treatment: comparison of laboratory and pilot scale dewatering results

2006 ◽  
Vol 54 (5) ◽  
pp. 33-41 ◽  
Author(s):  
D. Dursun ◽  
M. Turkmen ◽  
M. Abu-Orf ◽  
S.K. Dentel
Keyword(s):  
Extracellular Polymeric Substances ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Solid Content ◽  
Filter Press ◽  
Treatment Comparison ◽  
Anaerobically Digested Sludge ◽  
Network Strength ◽  
Pre Treatment ◽  
Solids Content

The effect of enzyme pre-treatment on dewaterability of anaerobically digested sludge was investigated at both laboratory and pilot scale. Our results revealed a significant increase in cake solid content (27% cake solids compared to 18% without enzyme pre-treatment), using an enzyme dose of only 20 mg/L. In order to assess practical application, enzyme pre-treatment was applied at the Wilmington, Delaware (US) wastewater treatment plant, using a pilot-scale centrifuge. However, the efficiency reached in laboratory scale could not be obtained in pilot scale, where the final cake solids content did not exceed 20%. Centrifuge and belt filter press (simulated by Crown Press™) dewatering were compared in terms of the process efficiencies in the absence and presence of enzyme pre-treatment. Possible factors that might cause the differences were tested by experimental and statistical comparisons. Results indicated that the higher shear applied in centrifugation is responsible for the lack of improved cake solids. The network strength of sludge determined by rheological measurements revealed that enzymatic treatment weakens the gel structure of the sludge floc through the hydrolysis of extracellular polymeric substances; this allows improved dewatering by filtration processes, but leads to floc deterioration when subjected to high shear during centrifugation.

A numerical study of the sedimentation of fibre suspensions

1998 ◽  
Vol 376 ◽  
pp. 149-182 ◽  
Author(s):  
MICHAEL B. MACKAPLOW ◽  
ERIC S. G. SHAQFEH
Keyword(s):  
Monte Carlo ◽  
Steady State ◽  
Monte Carlo Simulations ◽  
Numerical Study ◽  
Point Particle ◽  
Hydrodynamic Interactions ◽  
Dynamic Simulations ◽  
Slender Body Theory ◽  
Fibre Suspensions ◽  
The Mean

The sedimentation of fibre suspensions at low Reynolds number is studied using two different, but complementary, numerical simulation methods: (1) Monte Carlo simulations, which consider interparticle hydrodynamic interactions at all orders within the slender-body theory approximation (Mackaplow & Shaqfeh 1996), and (ii) dynamic simulations, which consider point–particle interactions and are accurate for suspension concentrations of nl3=1, where n and l are the number density and characteristic half-length of the fibres, respectively. For homogeneous, isotropic suspensions, the Monte Carlo simulations show that the hindrance of the mean sedimentation speed is linear in particle concentration up to at least nl3=7. The speed is well predicted by a new dilute theory that includes the effect of two-body interactions. Our dynamic simulations of dilute suspensions, however, show that interfibre hydrodynamic interactions cause the spatial and orientational distributions to become inhomogeneous and anisotropic. Most of the fibres migrate into narrow streamers aligned in the direction of gravity. This drives a downward convective flow within the streamers which serves to increase the mean fibre sedimentation speed. A steady-state orientation distribution develops which strongly favours fibre alignment with gravity. Although the distribution reaches a steady state, individual fibres continue to rotate in a manner that can be qualitatively described as a flipping between the two orientations aligned with gravity. The simulation results are in good agreement with published experimental data.

Network strength games: the core and the nucleolus

2018 ◽  
Vol 180 (1-2) ◽  
pp. 117-136
Author(s):  
Mourad Baïou ◽  
Francisco Barahona
Keyword(s):  
The Core ◽  
Network Strength

The Relationship between the Network Externalities of Complementary Modularity

2011 ◽  
Vol 486 ◽  
pp. 313-316
Author(s):  
Zu Ying Huang ◽  
Xing Liu
Keyword(s):  
Network Externalities ◽  
Equilibrium Price ◽  
The Core ◽  
Network Strength ◽  
The Relationship

This paper adds to the growing literature on the vertically specialized collaboration of modularity firms by applying a model in which complement and core products collaborate with each other in a network situation. More specifically, it investigates the influence of the complement’s network strength on the equilibrium price and output of the core product. The results thus characterize the relationship between the complement’s and the core products’ network strength during collaboration.

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