Floc Size Estimation of Fine Sediment Particles Using Sedimentation Test Data

Author(s):  
Chun-lei Zhang ◽  
Wei Jin ◽  
Xiao-yan Wu ◽  
Cong Yin
2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Zhipeng Shi ◽  
Genguang Zhang ◽  
Yuzhuo Zhang ◽  
Tingting He ◽  
Guoliang Pei

Flocculation is a special phenomenon for fine sediment or silt in reservoirs and estuaries. Flocculation usually results in changes of size, morphology, and settling velocity of sediment particles and finally changes of bed topography of reservoirs and estuaries. The process of flocculation and sedimentation was simulated based on population balance modeling (PBM) and computational fluid dynamics (CFD); the changes of particle or floc size and their settling velocities over time were examined. The results showed that flocculation is a dynamic and nonlinear process containing aggregation, breakage, reaggregation, and rebreakage between particles, microflocs, and macroflocs. Furthermore, the visual process of flocculation and sedimentation was directly created by the simulation results and is in good agreement with the results of the previous experiments.


2014 ◽  
Vol 17 (49) ◽  
Author(s):  
Perdamean Sebayang ◽  
Muljadi ◽  
Anggito Tetuko ◽  
Priyo Sardjono

Particle size distribution of Barium Hexaferrite sample has been performed with commonly used methods of mathematical models by Rosin-Rammler (RR model) distribution. By using sieving method from 20-400 mesh, the basis of network analysis distribution function F(d) and density function, f(d) were obtained. Particle size estimation was performed using sedimentation gravitation based on Stokes law to obtained Reynolds numbers and terminal velocity of flocs in medium value has been calculated. The results of Reynolds numbers shows that Barium hexaferrite flocs in ethanol medium in laminar flow, whereas terminal velocity increases as larger particle size and density, however, bulk density reduce due to contained highly porous in the sample which yields lower bulk density. The relationship of turbidity with the floc size has been evaluated. The results show that turbidity and bulk density increases as smaller particle size, meanwhile, terminal velocity reduced. Differences in turbidity for each sample (20-400 mesh) has been determined which shows two region instead, with first region from 150-850 µm yields larger differences compared to the second region: 37-105 µm.  


Author(s):  
Ole Larsen ◽  
William Davison ◽  
Kyriakos Vamvakopoulos ◽  
Flemming Møhlenberg

Author(s):  
Jumpei SUZUKI ◽  
Keiji KAWAKAMI ◽  
Takeshi YOSHIMURA ◽  
Hiroki SHINYA ◽  
Takahiro SATO ◽  
...  

2013 ◽  
Vol 04 (03) ◽  
pp. 407-414 ◽  
Author(s):  
Elizabeth A. Kunkel ◽  
Charles V. Privette ◽  
Calvin B. Sawyer ◽  
John C. Hayes

2016 ◽  
Vol 32 (3) ◽  
pp. 204-214 ◽  
Author(s):  
Emilie Lacot ◽  
Mohammad H. Afzali ◽  
Stéphane Vautier

Abstract. Test validation based on usual statistical analyses is paradoxical, as, from a falsificationist perspective, they do not test that test data are ordinal measurements, and, from the ethical perspective, they do not justify the use of test scores. This paper (i) proposes some basic definitions, where measurement is a special case of scientific explanation; starting from the examples of memory accuracy and suicidality as scored by two widely used clinical tests/questionnaires. Moreover, it shows (ii) how to elicit the logic of the observable test events underlying the test scores, and (iii) how the measurability of the target theoretical quantities – memory accuracy and suicidality – can and should be tested at the respondent scale as opposed to the scale of aggregates of respondents. (iv) Criterion-related validity is revisited to stress that invoking the explanative power of test data should draw attention on counterexamples instead of statistical summarization. (v) Finally, it is argued that the justification of the use of test scores in specific settings should be part of the test validation task, because, as tests specialists, psychologists are responsible for proposing their tests for social uses.


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