scholarly journals Semiempirical Model for Assessing Dewatering Process by Flocculation of Dredged Sludge in an Artificial Reservoir

2020 ◽  
Vol 10 (9) ◽  
pp. 3051 ◽  
Author(s):  
Bruno Molino ◽  
Gennaro Bufalo ◽  
Annamaria De Vincenzo ◽  
Luigi Ambrosone
Keyword(s):  
Particle Size ◽  
Clay Material ◽  
Semiempirical Model ◽  
Stage Model ◽  
Artificial Reservoir ◽  
Sediment Removal ◽  
Geotextile Tube ◽  
Planning Project ◽  
Dredged Sludge ◽  
Semi Empirical

Understanding sedimentation behaviour of clay material is crucial in planning project for sediment removal from bottom of a reservoir. The sedimentation of samples taken from Occhito reservoir ( Italy) is investigated. Samples containing and not containing polyacrylamide have been monitored. Results reveal that polymer induces bridging flocculation and the particle-size distribution tends to become uniform. The sedimentation profiles follow a mater curve. Such experimental observation is used to develop a semi-empirical model for assessment of dewatering process by flocculation of dredged sludge in artificial reservoir. A two-step stage model for assessing the volume of solids in a geotextile tube is suggested. Such model is based on the idea that for very long dewatering times solids reach the configuration of free sedimentation.

scholarly journals Improvement of Component Flux Estimating Model for Pervaporation Processes

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 418
Author(s):  
Botond Szilagyi ◽  
Andras Jozsef Toth
Keyword(s):  
Water Flux ◽  
Type Model ◽  
Semiempirical Model ◽  
Least Squares Approximation ◽  
Liquid Equilibrium ◽  
Alcohol Water ◽  
Significant Difference ◽  
Vle Data ◽  
Semi Empirical ◽  
First Time

Separating non-ideal mixtures by pervaporation (hence PV) is a competitive alternative to most traditional methods, such as distillation, which are based on the vapour–liquid equilibrium (VLE). It must be said, in many cases, accurate VLE data are already well known in the literature. They make the method of PV modelling a lot more complicated, and most of the viable models are (semi)empirical and focus on component flux (Ji) estimation. The pervaporation model of Mizsey and Valentinyi, which is based on Rautenbach’s works, is further improved in this work and tested rigorously by statistical means. Until now, this type of exponential modelling was only used for alcohol–water mixtures, but in this work, it was extended to an ethyl acetate–water binary mixture as well. Furthermore, a flowchart of modelling is presented for the first time in the case of an exponential pervaporation model. The results of laboratory-scale experiments were used as the basis of the study and least squares approximation was used to compare them to the different model’s estimations. According to our results, Valentinyi’s model (Model I) and the alternative model (Model III) appear to be the best methods for PV modelling, and there is no significant difference between the models, mainly in organophilic cases. In the case of the permeation component, Model I, which better follows the exponential function, is recommended. It is important to emphasize that our research confirms that the exponential type model seems to be universally feasible for most organic–water binary mixtures. Another novelty of the work is that after PDMS and PVA-based membranes, the accuracy of the semiempirical model for the description of water flux on a PEBA-based membrane was also proved, in the organophilic case.

scholarly journals Fatigue behaviour of open-hole samples and automotive mini-structures made of woven glass-fibre-reinforced polyamide 6,6

2018 ◽  
Vol 165 ◽  
pp. 07007
Author(s):  
Amélie Malpot ◽  
Fabienne Touchard ◽  
Sébastien Bergamo ◽  
Catherine Peyrac ◽  
Richard Montaudon ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Thermoplastic Composite ◽  
Semiempirical Model ◽  
Open Hole ◽  
Automotive Parts ◽  
Glass Fibre Reinforced ◽  
Semi Empirical ◽  
Non Destructive

In the automotive industry, the integration of thermoplastic composite components represents a high-potential solution to the mass reduction challenge. In this study, a woven glassfibre-reinforced composite with a polyamide 6,6 matrix is considered for the purpose of being integrated into automotive parts. Tension-tension fatigue tests were conducted on [(0/90)3] openhole samples. These tests were instrumented with non-destructive techniques, namely acoustic emission and infrared thermography. Acoustic emission results showed fibre-matrix debonding and fibre breakages in open-hole samples, located around the hole. Furthermore, 3-point bending fatigue tests were performed on “omega” mini-structures. A semi-empirical model was used in order to predict the fatigue lives of both open-hole coupons and automotive mini-structures. Predictions of the model for open-holes samples underestimate experimental fatigue lives. Nevertheless, the semiempirical model showed good results for the fatigue life prediction of composite mini-structures.

scholarly journals PCE and BNS admixture adsorption in sands with different composition and particle size distribution

2017 ◽  
Vol 67 (326) ◽  
pp. 121 ◽  
Author(s):  
M. M. Alonso ◽  
R. Martínez-Gaitero ◽  
S. Gismera-Diez ◽  
F. Puertas
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Water Demand ◽  
Mineralogical Composition ◽  
Practical Experience ◽  
Clay Material ◽  
Great Complexity

The choice of a superplasticiser (SP) for concrete is of great complexity, as it is well known that properties of the end product are related to admixture and its compatibility with concrete components. Very few studies have been conducted on the compatibility between SPs and the sand of mortars and concretes, however. Practical experience has shown that sand fineness and mineralogical composition affect water demand and admixture consumption. Clay-containing sand has been found also to adsorb SPs, reducing the amount available in solution for adsorption by the cement. This study analysed the isotherms for PCE and BNS superplasticiser adsorption on four sands with different fineness and compositions commonly used to prepare mortars and concretes. BNS-based SP did not adsorb on sands, while PCE-based admixtures exhibited variable adsorption depending on different factors. The adsorption curves obtained revealed that the higher the sand fineness, the finer the particle size distribution and the higher the clay material, the greater was PCE admixture adsorption/ consumption.

scholarly journals Semi-empirical Erosion Model with Particle Size and Liquid Water Content Effects for Ice Crystal Icing Simulations

2020 ◽  
Author(s):  
Virgile Charton ◽  
Jean-Mathieu Senoner ◽  
Pierre Trontin ◽  
Philippe Villedieu
Keyword(s):  
Particle Size ◽  
Water Content ◽  
Liquid Water ◽  
Liquid Water Content ◽  
Ice Crystal ◽  
Erosion Model ◽  
Semi Empirical

Second-law limitations on particle size distribution functions

1993 ◽  
Vol 440 (1910) ◽  
pp. 611-620 ◽  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Systematic Approach ◽  
System Size ◽  
Empirical Models ◽  
Distribution Functions ◽  
Second Law ◽  
Related Property ◽  
Semi Empirical ◽  
Size Distribution Of Particles

The size distribution of particles in dispersions is an important property that is usually measured. In many cases, however, theoretical or semi-empirical models are developed to predict these distributions. The models, none the less, come with subtle constraints that limit the régimes of their applicability. At present, there is no systematic approach for identifying these limitations, which, if ignored, can lead to serious flaws. In this work we introduce an entropy-related property of the dispersion, and demonstrate th at this property, which is intensive, and, therefore, independent of system size and configuration, can be used to pinpoint where these limitations lie.

scholarly journals Application of a Semi-Empirical Dynamic Model to Forecast the Propagation of the COVID-19 Epidemics in Spain

Forecasting ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 452-469
Author(s):  
Juan Carlos Mora ◽  
Sandra Pérez ◽  
Alla Dvorzhak
Keyword(s):  
Mathematical Model ◽  
Intensive Care ◽  
Good Accuracy ◽  
Logistic Map ◽  
Semiempirical Model ◽  
The Third ◽  
Third Phase ◽  
Daily Rate ◽  
Semi Empirical ◽  
The Mathematical Model

A semiempirical model, based in the logistic map, was developed to forecast the different phases of the COVID-19 epidemic. This paper shows the mathematical model and a proposal for its calibration. Specific results are shown for Spain. Four phases were considered: non-controlled evolution; total lock-down; partial easing of the lock-down; and a phased lock-down easing. For no control the model predicted the infection of a 25% of the Spanish population, 1 million would need intensive care and 700,000 direct deaths. For total lock-down the model predicted 194,000 symptomatic infected, 85,700 hospitalized, 8600 patients needing an Intensive Care Unit (ICU) and 19,500 deaths. The peak was predicted between the 29 March/3 April. For the third phase, with a daily rate r=1.03, the model predicted 400,000 infections and 46,000±15,000 deaths. The real r was below 1%, and a revision with updated parameters provided a prediction of 250,000 infected and 29,000±15,000 deaths. The reported values by the end of May were 282,870 infected and 28,552 deaths. After easing of the lock-down the model predicted that the health system would not saturate if r was kept below 1.02. This model provided good accuracy during epidemics development.

A Fabric Study of Clay Floccules

1973 ◽  
Vol 31 ◽  
pp. 202-203
Author(s):  
T. G. Naymik
Keyword(s):  
Particle Size ◽  
Electron Beam ◽  
Crystallite Size ◽  
Atomic Number ◽  
Coating Material ◽  
Specimen Preparation ◽  
Clay Material ◽  
Water Migration ◽  
Main Difficulty ◽  
Open Texture

Authigenic clays have been favored in SEM clay studies due to their large crystallite size, well developed individuals and open texture. Detrital clay material which is less stable under the electron beam, shows poor crvstal morphology and in general, smaller particle size is more difficult to observe.Specimen preparation is extremely important for viewing detrital clays. The main difficulty in photographing clays lies in the edge brightening effect inherent in clay platelets. Edge brightening arises from charging due to water migration from between clav platelets to the edges and from high atomic number coating material (gold) which tends to concentrate at the edges.

Effect of Filter Media Particle Size Distribution on Filtration Efficiency

1998 ◽  
Vol 33 (4) ◽  
pp. 589-594 ◽  
Author(s):  
F. Amini ◽  
H.V. Truong
Keyword(s):  
Water Quality ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Removal Efficiency ◽  
Scale Model ◽  
Filter Media ◽  
Sand Filter ◽  
Sediment Removal ◽  
Filter Water

Abstract The results of an experimental study of a sand filter water quality model are presented. The model is built to represent an underground confined water quality sand filter structure. Three types of sands, namely fine, medium and coarse, were used to study the effect of filter media particle size distribution on sediment removal efficiency. The results indicated that the sediment removal efficiency for all sand types decreased with time. The use of medium sand provided the scale model filter with the highest sediment removal efficiency. The finding of this study indicates that the media grain size has a measurable effect on the efficiency of the sand filter water quality structure.

Influence of particle size and size distribution in granular bed filtration and dynamic microfiltration

1997 ◽  
Vol 36 (4) ◽  
pp. 207-215 ◽  
Author(s):  
R. Ben Aim ◽  
S. Vigneswaran ◽  
H. Prasanthi ◽  
V. Jegatheesan
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Membrane Filtration ◽  
Particle Removal ◽  
Granular Bed ◽  
Lower Efficiency ◽  
Extensive Experimental Data ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Semi Empirical

Particle size and size distribution is an important parameter in solid liquid separation process especially in granular bed filtration and in dynamic microfiltration. This paper discusses their effects on the above processes from extensive experimental data obtained. In granular bed filtration, the experimental results showed that the initial efficiency follows the pattern reported by previous experimental and theoretical studies, i.e., lower efficiency for particles which fall in the range of critical size of 1 μm. However, the particle removal during the transient stage increased with an increase in particle size for the range of sizes studied. An attempt was made to quantify these effects in granular bed filtration using semi-empirical approach. In dynamic membrane filtration also, the particle size plays a major role in the retention. However, despite the relative thickness of the membrane (compared to particle size) dynamic microfiltration appears more as a sieving process; the retention is mainly related to the largest pore size.

scholarly journals Mineralogical analysis of Brazilian ceramic sedimentary clays used in red ceramic

Cerâmica ◽  
2005 ◽  
Vol 51 (320) ◽  
pp. 382-387 ◽  
Author(s):  
G. P. Souza ◽  
S. J. G. Sousa ◽  
L. A. H. Terrones ◽  
J. N. F. Holanda
Keyword(s):  
Thermal Analysis ◽  
Particle Size ◽  
Chemical Composition ◽  
Clay Material ◽  
Loss On Ignition ◽  
X Ray Diffraction ◽  
Mineralogical Analysis ◽  
X Ray ◽  
High Loss

The present work focuses on the mineralogical analysis of sedimentary clay material samples collected from deposits located in the Campos dos Goytacazes-RJ (Brazil) region. These samples are representative and widely used by the ceramic plants in production of bricks and roofing tiles. The samples were selected with the objective of analyzing their characteristics regarding chemical composition, loss on ignition, X-ray diffraction, morphology, particle size, plasticity and thermal analysis. The sedimentary red clays have low amount of SiO2, high amount of Al2O3, and high loss on ignition. In addition, it was found that the character of the clays is typically kaolinitic.

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