Water Based Colloidal Processing of Ceramic Laminates

2007 ◽  
Vol 333 ◽  
pp. 39-48 ◽  
Author(s):  
Antonio Javier Sanchez-Herencia
Keyword(s):  
Processing Parameters ◽  
Colloidal Processing ◽  
Water Separation ◽  
Green Strength ◽  
Water Based ◽  
The Stability ◽  
Deflection Criteria ◽  
Joining Strength ◽  
Processing Techniques ◽  
Laminated Structures

Multilayered materials and coating are complex structures proposed among others to face the structural requirements of ceramics. The development of reinforcement mechanism by laminated structures can be due to deflection criteria or to the presence of residual stresses and requires of tailored laminates. These designs are characterized by the phases, thickness and distribution of the layers as well as the joining strength between them. In this sense water based colloidal processing techniques are used to fabricate layered structures by consolidating the layers from fluid dispersions of the powders in water. In these processing methods the phases presented in the final laminate are mainly given by the composition of the starting slurries while the changes in thickness and sharpness of the layers are controlled by acting on the processing parameters. The achievement of stable slurries is a shared step for all the colloidal processing techniques. In the water based slurries the stability will be dominated by the polar media, the surface behavior of the particles and the presence of dispersant additives to increase the repulsion between particles. The stable slurry ensures an effective milling and dispersion of the phases as well as high solid loadings, if required. Further processes associated to shaping and consolidation of the layers requires the incorporation of additives and-or water removal. The shaping methods based on aqueous slurries can be classified taking into account the process of solid-water separation. For each of those shaping methods, the nature and amount of the additives is different in order to get the optimum rheological behavior and green strength after drying. Depending on the thickness of layers and coatings as well as the shape and dimensions of the samples, the shaping method can be selected alone and combined with others.

Effect of particle concentration on the stability of water-based SiO2 nanofluid

2021 ◽  
Vol 379 ◽  
pp. 457-465
Author(s):  
Tiancheng Zhang ◽  
Quanle Zou ◽  
Zhiheng Cheng ◽  
Zihan Chen ◽  
Ying Liu ◽  
...  
Keyword(s):  
Particle Concentration ◽  
Water Based ◽  
The Stability ◽  
Stability Of Water

scholarly journals Post-Processing Techniques for the Improvement of Liposome Stability

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1023
Author(s):  
Ji Young Yu ◽  
Piyanan Chuesiang ◽  
Gye Hwa Shin ◽  
Hyun Jin Park
Keyword(s):  
Freeze Drying ◽  
Protective Agent ◽  
Post Processing ◽  
Additional Process ◽  
Spray Freeze Drying ◽  
The Stability ◽  
Processing Techniques ◽  
The Impact ◽  
Self Aggregation ◽  
Liposome Stability

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.

Stability of a Binary Colloidal Suspension and its effect on Colloidal Processing

1989 ◽  
Vol 155 ◽  
Author(s):  
Wan V. Shih ◽  
Wei-Heng Shih ◽  
Jun Liu ◽  
Ilhan A. Aksay
Keyword(s):  
Particle Size ◽  
Hard Sphere ◽  
Colloidal Particles ◽  
Colloidal Suspension ◽  
Fluid Phase ◽  
Ceramic Processing ◽  
Colloidal Processing ◽  
Interparticle Interactions ◽  
The Stability ◽  
Binary Suspension

The stability of a colloidal suspension plays an important role in colloidal processing of materials. The stability of the colloidal fluid phase is especially vital in achieving high green densities. By colloidal fluid phase, we refer to a phase in which colloidal particles are well separated and free to move about by Brownian motion, By controlling parameters such as pH, salt concentration, and surfactants, one can achieve high packing (green) densities in the repulsive regime where the suspension is well dispersed as a colloidal fluid, and low green densities in the attractive regime where the suspensions are flocculated [1,2]. While there is increasing interest in using bimodal suspensions to improve green densities, neither the stability of a binary suspension as a colloidal fluid nor the stability effects on the green densities have been studied in depth as yet. Traditionally, the effect of using bimodal-particle-size distribution has only been considered in terms of geometrical packing developed by Furnas and others [3,4]. This model is a simple packing concept and is used and useful for hard sphere-like repulsive interparticle interactions. With the advances in powder technology, smaller and smaller particles are available for ceramic processing. Thus, the traditional consideration of geometrial packing for the green densities of bimodal suspensions may not be enough. The interaction between particles must be taken into account.

scholarly journals The Energy-Efficient Processing of Fine Materials by the Micropyretic Synthesis Route

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
H. P. Li
Keyword(s):  
Energy Efficient ◽  
Processing Time ◽  
Combustion Temperature ◽  
Processing Parameters ◽  
The Novel ◽  
Diffusion Controlled ◽  
Efficient Processing ◽  
The One ◽  
Processing Techniques ◽  
Diffusion Controlled Reaction

Energy-efficient processing of TiB compound with nanowhiskers by micropyretic synthesis is investigated in this paper. Micropyretic synthesis not only offers shorter processing time but also excludes the requirement for high-temperature sintering and it is considered as the one of the novel energy-saving processing techniques. Experimental study and numerical simulation are both carried out to investigate the correlation of the processing parameters on the microstructures of the micropyretically synthesized products. The diffusion-controlled reaction mechanism is proposed in this study. It is noted that nanosize TiB whiskers only occurred when the combustion temperature is lower than the melting point of TiB but higher than the extinguished temperature. The results generated in the numerical calculation can be used as a helpful reference to select the proper route of processing nanosize materials. The Arrhenius-type plot of size and temperature is used to calculate the activation energy of TiB reaction. In addition to verifying the accuracy of the experimental measures, the reaction temperature for producing the micropyretically synthesized products with nanofeatures can be predicted.

A new three-phase heterocrystal catalysts and their superior treatment efficiency for tetracycline

2016 ◽  
Vol 10 (03) ◽  
pp. 1750015
Author(s):  
Feng-Rui Wang ◽  
Hui-Ping Sun ◽  
Yan Wang ◽  
Jin-Ku Liu ◽  
Yi Fang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Band Structure ◽  
Antibiotic Residues ◽  
Treatment Efficiency ◽  
Electron Hole ◽  
Three Phase ◽  
Catalytic Material ◽  
Water Based ◽  
The Stability ◽  
Functional Components

An easy recyclable and interesting Ag3PO4@Pt@TiO2 (APTP) three-phase heterocrystal chains were self-assembled by the cohesive action and chemical construction of polyvinylpyrrolidone (PVP). We found that a new electron–hole transmission path has been built via the rematch of the band structure of Ag3PO4, Pt and TiO2 which extends the light absorption and promoted the electron–hole separation to treat the antibiotic residues in the water. Based on the thorough investigations, a new catalytic material was provided for antibiotics degradation. The catalytic activity of APTP toward the degradation of tetracycline solution was enhanced by 166.67% and the stability increased remarkably compared with pure Ag3PO4 through the integration of different functional components.

scholarly journals Comprehensive ensuring of quality of surfaces of details at centrifugal-planetary volume processing

2018 ◽  
Vol 224 ◽  
pp. 01123 ◽  
Author(s):  
Alexander Zverovshchikov ◽  
Vladimir Zverovshchikov ◽  
Sergey Nesterov
Keyword(s):  
Finite Element Method ◽  
System Analysis ◽  
Processing Parameters ◽  
Modeling Processes ◽  
Working Fluid ◽  
The Finite Element Method ◽  
The Stability ◽  
Abrasive Working ◽  
Bulk Processing

The results of the system analysis of the set of input factors of the volumetric centrifugal-planetary processing, allowing to implement a comprehensive approach to the provision of quality processing parameters, are considered. A sequence of modeling processes ensuring the quality of surfaces during bulk processing is given. The results of modeling the contact of an abrasive working body with the surface of a workpiece with a microrelief are shown. The factors determining the stability of reliable achievement of qualitative indicators are noted. A dependence has been developed to determine the parameter of the surface roughness to be reduced, based on the results of modeling the contact between the surfaces of the working fluid and the workpiece by the finite element method. The experience of designing volumetric centrifugal processing operations on the basis of modeling is generalized. Methodical methods of technological preparation of manufacture for volumetric processing are offered.

scholarly journals Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 978
Author(s):  
Yi Zhang ◽  
Yang Gan ◽  
Liwen Zhang ◽  
Deyuan Zhang ◽  
Huawei Chen
Keyword(s):  
Surface Tension ◽  
Underlying Mechanism ◽  
Structural Features ◽  
Liquid Motion ◽  
Water Separation ◽  
Lab On Chip ◽  
Liquid Spreading ◽  
Oil Water Separation ◽  
On Chip ◽  
The Stability

Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil–water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications.

Plasma spray process modelling using artificial neural networks: Application to Al2O3-TiO2 (13% by weight) ceramic coating structure

2004 ◽  
Vol 120 ◽  
pp. 363-370
Author(s):  
S. Guessasma ◽  
G. Montavon ◽  
C. Coddet
Keyword(s):  
Thermal Spraying ◽  
Processing Parameters ◽  
Ceramic Coatings ◽  
Physical Models ◽  
Spray Process ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
The Stability ◽  
Experimental Values ◽  
Physical Phenomena

Thermal spraying is a versatile technique of coating manufacturing implementing large variety of materials and processes. The manufacture control is constrained by the understanding of the physical phenomena occurring during the spraying. It is however penalized by the large number of processing parameters (up to 50), their interdependencies, their correlations with the coating attributes and the stability of the process. Numerous statistical, heuristic or physical models intended to response to these constrains, very often partially because considering some aspects of the process. This work aims at considering a more global approach based on a powerful statistical methodology using artificial intelligence. Following this approach, the physical phenomena are encoded in a structure called Artificial Neural Network (ANN). An application of the ANN methodology is discussed in the case of the APS spray process. Some processing parameters categories are related to some coating properties for alumina-titania (13% by weight) ceramic coatings. ANN optimization is presented and discussed. Predicted results show globally a well agreement with the experimental values. Some conclusions point out the advantages of the ANN on the conventional methods, such as the design of experiments, used usually to recognize the controlling factors in a process.

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