Effect of pipe inclination on internal structure of settling slurry flow at and close to deposition limit

Inclined slurry flows occur often in industrial applications such as mining and dredging. Pipelines transporting slurries contain inclined sections of various lengths and slopes. If the transported slurry is settling slurry then pipe inclination considerably affects flow structure and behavior. We discuss settling slurry flow near and at the deposition limit at which stationary deposit starts to be formed at the bottom of the pipe. In particular, we focus on the effect of the pipe slope on the deposition velocity, and on the solids distribution and manometric hydraulic gradient in flow round the deposition limit. We introduce our new layered model for inclined settling slurry flows and demonstrate its predictive capabilities. Model predictions are verified by our experiment in a laboratory loop. We also introduce our new experimental approach to a detection of the deposition velocity based on radiometric sensing of the change of local concentration of solids at the bottom of a pipe. Our experiments cover a broad range of flow slopes and contain measurements of solids distribution in a pipe cross section. Experimental results show that the degree of flow stratification and frictional pressure drop decrease with the increasing angle of inclination in the ascending pipe while the opposite applies in the descending pipe, which affects the deposition velocity and other related flow parameters. A comparison with model predictions demonstrates that experimentally observed effects of pipe inclination are reproduced well by the layered model. Predicted deposition velocities, pressure drops and solids distributions are in a good agreement with the experimental results and indicate suitability of the model for engineering practice.

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Modelling approaches for pipe inclination effect on deposition limit velocity of settling slurry flow

EPJ Web of Conferences ◽

10.1051/epjconf/201818002062 ◽

2018 ◽

Vol 180 ◽

pp. 02062 ◽

Cited By ~ 1

Author(s):

Václav Matoušek ◽

Mikoláš Kesely ◽

Pavel Vlasák

Keyword(s):

Predictive Models ◽

Particle Deposition ◽

Deposition Velocity ◽

Solid Particles ◽

Slurry Flow ◽

Threshold Velocity ◽

Horizontal Pipe ◽

Slurry Flows ◽

Modelling Approaches ◽

Pipe Inclination

The deposition velocity is an important operation parameter in hydraulic transport of solid particles in pipelines. It represents flow velocity at which transported particles start to settle out at the bottom of the pipe and are no longer transported. A number of predictive models has been developed to determine this threshold velocity for slurry flows of different solids fractions (fractions of different grain size and density). Most of the models consider flow in a horizontal pipe only, modelling approaches for inclined flows are extremely scarce due partially to a lack of experimental information about the effect of pipe inclination on the slurry flow pattern and behaviour. We survey different approaches to modelling of particle deposition in flowing slurry and discuss mechanisms on which deposition-limit models are based. Furthermore, we analyse possibilities to incorporate the effect of flow inclination into the predictive models and select the most appropriate ones based on their ability to modify the modelled deposition mechanisms to conditions associated with the flow inclination. A usefulness of the selected modelling approaches and their modifications are demonstrated by comparing model predictions with experimental results for inclined slurry flows from our own laboratory and from the literature.

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X-ray microtomography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107058 ◽

1988 ◽

Vol 46 ◽

pp. 998-999

Author(s):

H.W. Deckman ◽

B.F. Flannery ◽

J.H. Dunsmuir ◽

K.D' Amico

Keyword(s):

Computed Tomography ◽

Internal Structure ◽

Imaging Technique ◽

Three Dimensional ◽

Tissue Structure ◽

Individual Element ◽

X Ray ◽

Non Invasive ◽

Panoramic Imaging ◽

Three Dimensional Images

We have developed a new X-ray microscope which produces complete three dimensional images of samples. The microscope operates by performing X-ray tomography with unprecedented resolution. Tomography is a non-invasive imaging technique that creates maps of the internal structure of samples from measurement of the attenuation of penetrating radiation. As conventionally practiced in medical Computed Tomography (CT), radiologists produce maps of bone and tissue structure in several planar sections that reveal features with 1mm resolution and 1% contrast. Microtomography extends the capability of CT in several ways. First, the resolution which approaches one micron, is one thousand times higher than that of the medical CT. Second, our approach acquires and analyses the data in a panoramic imaging format that directly produces three-dimensional maps in a series of contiguous stacked planes. Typical maps available today consist of three hundred planar sections each containing 512x512 pixels. Finally, and perhaps of most import scientifically, microtomography using a synchrotron X-ray source, allows us to generate maps of individual element.

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The internal structure of medullated wool

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111987 ◽

1984 ◽

Vol 42 ◽

pp. 388-389

Author(s):

Leo Barish

Keyword(s):

Light Microscopy ◽

Internal Structure ◽

Wool Fiber ◽

Guard Hair ◽

Bright Field ◽

Wool Fibers ◽

Thin Skin ◽

Air Pockets

Although most of the wool used today consists of fine, unmedullated down-type fibers, a great deal of coarse wool is used for carpets, tweeds, industrial fabrics, etc. Besides the obvious diameter difference, coarse wool fibers are often medullated.Medullation may be easily observed using bright field light microscopy. Fig. 1A shows a typical fine diameter nonmedullated wool fiber, Fig. IB illustrates a coarse fiber with a large medulla. The opacity of the medulla is due to the inability of the mounting media to penetrate to the center of the fiber leaving air pockets. Fig. 1C shows an even thicker fiber with a very large medulla and with very thin skin. This type of wool is called “Kemp”, is shed annually or more often, and corresponds to guard hair in fur-bearing animals.

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The German Post-Critical Belief Scale: Internal and External Validity

Zeitschrift für Sozialpsychologie ◽

10.1024/0044-3514.34.4.219 ◽

2003 ◽

Vol 34 (4) ◽

pp. 219-226 ◽

Cited By ~ 7

Author(s):

Bart Duriez ◽

Claudia Appel ◽

Dirk Hutsebaut

Keyword(s):

Internal Structure ◽

Present Article ◽

External Validity ◽

German Version ◽

Dutch Version ◽

German Sample ◽

Belief Scale ◽

Internal And External Validity

Abstract: Recently, Duriez, Fontaine and Hutsebaut (2000) and Fontaine, Duriez, Luyten and Hutsebaut (2003) constructed the Post-Critical Belief Scale in order to measure the two religiosity dimensions along which Wulff (1991 , 1997 ) summarized the various possible approaches to religion: Exclusion vs. Inclusion of Transcendence and Literal vs. Symbolic. In the present article, the German version of this scale is presented. Results obtained in a heterogeneous German sample (N = 216) suggest that the internal structure of the German version fits the internal structure of the original Dutch version. Moreover, the observed relation between the Literal vs. Symbolic dimension and racism, which was in line with previous studies ( Duriez, in press ), supports the external validity of the German version.

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Internal Structure of the Spanish Adaptation of the Eating Disorder Inventory-3

European Journal of Psychological Assessment ◽

10.1027/1015-5759/a000087 ◽

2012 ◽

Vol 28 (1) ◽

pp. 25-31 ◽

Cited By ~ 7

Author(s):

Paula Elosua ◽

Alicia López-Jáuregui

Keyword(s):

Eating Disorders ◽

Eating Disorder ◽

Internal Structure ◽

Internal Consistency ◽

Clinical Sample ◽

Temporal Stability ◽

Second Order ◽

Order Structure ◽

Eating Disorder Inventory ◽

High Internal Consistency

In this study the Eating Disorder Inventory-3 was adapted to Spanish and analyzed the internal psychometric properties of the test in a clinical sample of females with eating disorders. The results showed a high internal consistency of the scores as well as high temporal stability. The factor structure of the scale composites was analyzed using confirmatory factor analysis. The results supported the existence of a second-order structure beyond the psychological composites. The second-order factor showed high correlation with the factor related to eating disorders. Overall, the Spanish version of the EDI-3 showed good psychometric qualities in terms of internal consistency, temporal stability and internal structure.

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