scholarly journals An Innovative Miniature Pulsating Emulsification Device: Flow Characterization and Measurement of Emulsion Stability

2020 ◽  
Vol 4 (1) ◽  
pp. 7
Author(s):  
Chondrou ◽  
Evgenidis ◽  
Kostoglou ◽  
Karapantsios
Keyword(s):  
Droplet Size Distribution ◽  
Immiscible Liquids ◽  
Rectangular Cell ◽  
Shear Rates ◽  
Flow Characterization ◽  
Piston Stroke ◽  
Parameter Values ◽  
Plate Geometry ◽  
Emulsions Stability

The aim of this study is the development of an emulsification device for two immiscible liquids with a total volume of approximately 3 mL. The heart of the device is a piston, with an aluminum plate fixed at its tip, which moves periodically up and down inside a rectangular cell. The plate geometry (uniform or non-uniform height) affects significantly both the emulsions stability and the size of the droplets of the prepared emulsions. Five parameters are examined during testing (surfactant type, surfactant concentration, proportion of immiscible liquids, piston stroke frequency, duration of emulsification) and all of them appear to have an important role in the resulting droplet size distribution. A macroscopic theoretical model is developed for the determination of the main hydrodynamic parameters of the innovative device. It is shown that the non-uniform height plate achieves higher shear rates when compared to the uniform height plate because of the smaller gap between the plate and the cell walls. However, the benefits of the higher shear rate are overturned by the larger effective breakage time encountered in the uniform height plate resulting from the larger surface area of its sides. The results of the emulsification experiments are analyzed using the parameter values derived by the developed model.

scholarly journals Experimental determination and modeling of flow curves of xanthan gum solutions over a large range of shear rates

2021 ◽  
Vol 31 (1) ◽  
pp. 24-38
Author(s):  
Julian Sepulveda ◽  
Agnes Montillet ◽  
Dominique Della Valle ◽  
Thanina Amiar ◽  
Hubert Ranchon ◽  
...  
Keyword(s):  
Shear Rate ◽  
Xanthan Gum ◽  
Scaling Law ◽  
Polymer Concentration ◽  
High Shear ◽  
Shear Rates ◽  
Wide Range ◽  
Different Diameters ◽  
Plate Geometry

Abstract The viscosities of solutions formulated with xanthan gum and xanthan gum with whey protein isolates are experimentally characterized and modeled over a wide range of shear rates [10−3 to 105 s−1]. As shown by numerous studies [1, 2], the generation of vortices in the cone-plate geometry is making viscosity measurements beyond a certain shear rate unreliable. In the present work, an innovative technique, based on microfluidics and developed by the company Formulaction, has been employed to extend to high shear rates, the viscosity flow curve obtained with a rotational rheometer. The main highlights of this study are firstly, to propose a scaling law for the inertial transition in the cone-plate geometry for different diameters and angles through the determination of the maximum shear rate at which one can expect a true viscosity value. Secondly, the high shear rate measurements allow the determination of the second Newtonian plateau for these solutions thanks to the Williams-Carreau model. An attempt for the second plateau modeling is proposed following the concept of an intrinsic viscosity in the high shear equilibrium. In the same way, other fitted parameters from the Williams-Carreau law are modeled as a function of the polymer concentration. This procedure allows to provide a predictive model for the rheological behavior of xanthan gum-based solutions used in high shear processes like high pressure homogenization, emulsification, foaming, microfluidics, etc in food, pharmaceutical or cosmetics applications.

scholarly journals Effect of data quality on estimates of farm infectiousness trends in the UK 2001 foot-and-mouth disease epidemic

2006 ◽  
Vol 4 (13) ◽  
pp. 235-241 ◽  
Author(s):  
Nicholas J Savill ◽  
Darren J Shaw ◽  
Rob Deardon ◽  
Michael J Tildesley ◽  
Matthew J Keeling ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Data Quality ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Inaccurate Data ◽  
Foot And Mouth ◽  
The Uk ◽  
Parameter Values

Most of the mathematical models that were developed to study the UK 2001 foot-and-mouth disease epidemic assumed that the infectiousness of infected premises was constant over their infectious periods. However, there is some controversy over whether this assumption is appropriate. Uncertainty about which farm infected which in 2001 means that the only method to determine if there were trends in farm infectiousness is the fitting of mechanistic mathematical models to the epidemic data. The parameter values that are estimated using this technique, however, may be influenced by missing and inaccurate data. In particular to the UK 2001 epidemic, this includes unreported infectives, inaccurate farm infection dates and unknown farm latent periods. Here, we show that such data degradation prevents successful determination of trends in farm infectiousness.

scholarly journals Comparative Study of Optimization Algorithms for The Optimal Reservoir Operation

2018 ◽  
Vol 246 ◽  
pp. 01003
Author(s):  
Xinyuan Liu ◽  
Yonghui Zhu ◽  
Lingyun Li ◽  
Lu Chen
Keyword(s):  
Reservoir Operation ◽  
Optimization Problems ◽  
Optimization Algorithms ◽  
Complex Problem ◽  
Optimization Techniques ◽  
Decision Variables ◽  
Handling Methods ◽  
Optimality Algorithm ◽  
Parameter Values

Apart from traditional optimization techniques, e.g. progressive optimality algorithm (POA), modern intelligence algorithms, like genetic algorithms, differential evolution have been widely used to solve optimization problems. This paper deals with comparative analysis of POA, GA and DE and their applications in a reservoir operation problem. The results show that both GA and DES are feasible to reservoir operation optimization, but they display different features. GA and DE have many parameters and are difficult in determination of these parameter values. For simple problems with mall number of decision variables, GA and DE are better than POA when adopting appropriate parameter values and constraint handling methods. But for complex problem with large number of variables, POA combined with simplex method are much superior to GA and DE in time-assuming and quality of optimal solutions. This study helps to select proper optimization algorithms and parameter values in reservoir operation.

scholarly journals Investigation of kinematic parameters of two nonconventional piston machines with wobble board

2018 ◽  
Vol 157 ◽  
pp. 02003 ◽  
Author(s):  
Peter Baran ◽  
Pavol Šťastniak ◽  
Pavol Kukuča ◽  
Miloš Brezáni
Keyword(s):  
Dynamic Model ◽  
Main Part ◽  
Engineering Industry ◽  
Force Analysis ◽  
Movement Behaviour ◽  
Kinematic Parameters ◽  
Geometric Conditions ◽  
Piston Stroke ◽  
Basic Movement

Article deals with description of non-conventional mechanism FIK and mechanism with ring, which may be suitable for special applications in the engineering industry. It is possible to use not only classical crank mechanisms, but also non-conventional mechanisms in design of piston machines. Investigation of kinematic parameters of the machines is important step to know its basic movement behaviour, and from this, it is then possible to create the alternate dynamic model or force analysis. For kinematic comparison will be designed the same basic geometric conditions in both types of models. In terms of comparisons will be monitored mainly points on wobble board and the main part will be determination of piston stroke.

scholarly journals Experimental Investigation of a Prandtl Probe Fabricated Using Desktop Stereolithography Technology

2020 ◽  
Vol 5 (10) ◽  
pp. 1274-1280
Author(s):  
Alfred Gift Mwachugha ◽  
Jean Byiringiro ◽  
Harrison Ngetha ◽  
Thomas Carolus ◽  
Kathrin Stahl
Keyword(s):  
Additive Manufacturing ◽  
Wind Tunnel ◽  
Accurate Determination ◽  
Wind Tunnels ◽  
Research Institution ◽  
Flow Characterization ◽  
Desktop Manufacturing ◽  
Flow Quality ◽  
Manufacturing Platform

A Prandtl probe is one of the standard instruments used for flow characterization in wind tunnel facilities. The convectional fabrication method of this instrument requires skilled artisanship, precision drilling, lathing and soldering of its several parts. This reflects into high costs of production in turn making wind energy studies expensive. With the adoption of additive manufacturing, the tooling costs, skills required and design to manufacture constraints can be addressed. This research presents a Prandtl probe that was designed using NX™ software, fabricated by desktop stereolithography additive manufacturing platform and validated in a wind tunnel for velocity range of 0 m/s to 51 m/s. This research attested the option of fabricating relatively cheap functional Prandtl probe with desktop stereolithography technology which can be used for accurate determination of flow quality in wind tunnels experiments. This provides various learning and research institution in developing countries that have already invested in additive desktop manufacturing technology certainty and a cheaper option to fabricate wind research instruments for use at their laboratories. Moreover, fabrication and validation of a 5-hole Prandtl probe can also be examined.

scholarly journals Lecture Scheduling Automation Using Genetic Algorithm

2019 ◽  
Vol 8 (5C) ◽  
pp. 1444-1447
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Test Results ◽  
Scheduling Problems ◽  
Scheduling System ◽  
Parameter Values

This paper aims produce an academic scheduling system using Genetic Algorithm (GA) to solve the academic schedule. Factors to consider in academic scheduling are the lecture to be held, the available room, the lecturers and the time of the lecturer, the suitability of the credits with the time of the lecture, and perhaps also the time of Friday prayers, and so forth. Genetic Algorithms can provide the best solution for some solutions in dealing with scheduling problems. Based on the test results, the resulting system can automate the scheduling of lectures properly. Determination of parameter values in Genetic Algorithm also gives effect in producing the solution of lecture schedule

Basic Concepts of Nanoemulsion and its Potential application in Pharmaceutical, Cosmeceutical and Nutraceutical fields

2021 ◽  
pp. 3938-3946
Author(s):  
Heba S. Elsewedy ◽  
Bandar E. Al-Dhubiab ◽  
Mahmoud A. Mahdy ◽  
Hanan M. Elnahas
Keyword(s):  
Drug Delivery ◽  
Colloidal Dispersions ◽  
Immiscible Liquids ◽  
Pharmaceutical Dosage Form ◽  
Regulatory Aspects ◽  
Conventional Drug ◽  
Emulsifying Agent ◽  
Basic Concepts ◽  
Physical And Chemical

One of the widely efficient and noteworthy nanocarriers that could draw a great attention toward pharmaceutical fields is nanoemulsions (NEs). NEs are thermodynamically stable colloidal dispersions composed of two immiscible liquids, oil and water that mixed together using emulsifying agent (surfactant and co-surfactant). It regarded as pharmaceutical dosage form having droplet size within a nanometer range, hence it has extensively considered as carrier for delivering active agents. Such carrier is fabricated in order to overcome some obstacles associated with conventional drug delivery systems especially low bioavailability. The objective of this review is to present an overview about NE and its latest applications in diverse areas such as drug delivery, cosmeceutical and nutraceutical. Clarifications about different mechanisms of NEs development that are frequently used were provided. Correspondingly, popular characterization techniques for NEs such as determination of particle size, polydispersity index (PDI), zeta potential and viscosity were reviewed. Eventually, summary of physical and chemical instability in addition to the regulatory aspects of NE were provided.

Model Verification of Mixed Dynamic Systems

1978 ◽  
Vol 100 (2) ◽  
pp. 266-273 ◽  
Author(s):  
J. D. Chrostowski ◽  
D. A. Evensen ◽  
T. K. Hasselman
Keyword(s):  
Experimental Data ◽  
Parameter Estimation ◽  
Dynamic Systems ◽  
Statistical Parameter ◽  
Model Verification ◽  
Passive Networks ◽  
Parameter Values ◽  
Basic Configuration ◽  
General Method

A general method is presented for using experimental data to verify math models of “mixed” dynamic systems. The term “mixed” is used to suggest applicability to combined systems which may include interactive mechanical, hydraulic, electrical, and conceivably other types of components. Automatic matrix generating procedures are employed to facilitate the modeling of passive networks (e.g., hydraulic, electrical). These procedures are augmented by direct matrix input which can be used to complement the network model. The problem of model verification is treated in two parts; verification of the basic configuration of the model and determination of the parameter values associated with that configuration are addressed sequentially. Statistical parameter estimation is employed to identify selected parameter values, recognizing varying degrees of uncertainty with regard to both experimental data and analytical results. An example problem, involving a coupled hydraulic-mechanical system, is included to demonstrate application of the method.

Numerical Determination of Two-Phase Material Parameters of a Gas Diffusion Layer Using Tomography Images

2008 ◽  
Vol 5 (2) ◽  
Author(s):  
Jürgen Becker ◽  
Volker Schulz ◽  
Andreas Wiegmann
Keyword(s):  
Diffusion Layer ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Pore Morphology ◽  
Two Phase ◽  
Material Parameters ◽  
3D Tomography ◽  
Tomography Image ◽  
Parameter Values

In this paper, we give a complete description of the process of determining two-phase material parameters for a gas diffusion layer: Starting from a 3D tomography image of the gas diffusion layer the distribution of gas and water phases is determined using the pore morphology method. Using these 3D phase distributions, we are able to determine permeability, diffusivity, and heat conductivity as a function of the saturation of the porous medium with comparatively low numerical costs. Using a reduced model for the compression of the gas diffusion layer, the influence of the compression on the parameter values is studied.

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