Biomedical Engineered Ferrofluids

2007 ◽  
Vol 1032 ◽  
Author(s):  
Birgit Fischer ◽  
Leidong Mao ◽  
Mustafa Gungormus ◽  
Candan Tamerler-Behar ◽  
Mehmet Sarikaya ◽  
...  
Keyword(s):  
Colloidal Stability ◽  
Ac Susceptibility ◽  
Medical Application ◽  
Genetically Engineered ◽  
Monodisperse Particles ◽  
New Approach ◽  
Water Based ◽  
Liquid Behavior ◽  
Efficient Route ◽  
The Stability

AbstractThe characteristic of combining liquid behavior with and magnetic properties makes ferrofluids unique and it provides them a variety of applications, in particular in the medial field. For medical application ferrofluids are required to be stable at neutral pH and against high salt concentration. Here we present a new approach to stabilize water-based ferrofluids by using genetically engineered peptides for inorganics (GEPI's). Such GEPI's selected for specific and strong binding to the surface of nanoparticles not only increase colloidal stability by acting as a thin surfactant, but they also enable an efficient route for rendering the ferrofluid bio-functional and bio-compatible. The stability of a ferrofluid was characterized by the ac-susceptibility and by using it in a ferro-microfluidic device. This chip actuates the ferrofluid directly via magnetic fields alone, and the pumping spectrum as a function of frequency reveals information about the size of the magnetic nanoparticles. An ideal ferrofluid with monodisperse particles displays a single and clear pumping peak. Agglomeration can directly be observed as a broadening of the pumping spectrum.

Host-Guest Interactions on Electrode Surfaces for Immobilization of Molecular Catalysts

2020 ◽  
Author(s):  
Laurent Sévery ◽  
Jacek Szczerbiński ◽  
Mert Taskin ◽  
Isik Tuncay ◽  
Fernanda Brandalise Nunes ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Heterogeneous Systems ◽  
Catalytic Systems ◽  
New Approach ◽  
Molecular Systems ◽  
Electrode Surfaces ◽  
Catalytic Surfaces ◽  
Oxide Electrodes ◽  
The Stability ◽  
Molecular Catalysts

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.

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 Methodology and Models for Individuals’ Creditworthiness Management Using Digital Footprint Data and Machine Learning Methods

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1820
Author(s):  
Ekaterina V. Orlova
Keyword(s):  
Interest Rates ◽  
Additional Data ◽  
Risk Level ◽  
Gradient Boosting ◽  
Cluster Number ◽  
New Approach ◽  
Credit Risks ◽  
Stochastic Gradient Boosting ◽  
The Stability ◽  
Digital Footprints

This research deals with the challenge of reducing banks’ credit risks associated with the insolvency of borrowing individuals. To solve this challenge, we propose a new approach, methodology and models for assessing individual creditworthiness, with additional data about borrowers’ digital footprints to implement comprehensive analysis and prediction of a borrower’s credit profile. We suggest a model for borrowers’ clustering based on the method of hierarchical clustering and the k-means method, which groups actual borrowers having similar creditworthiness and similar credit risks into homogeneous clusters. We also design the model for borrowers’ classification based on the stochastic gradient boosting (SGB) method, which reliably determines the cluster number and therefore the risk level for a new borrower. The developed models are the basis for decision making regarding the decision about lending value, interest rates and lending terms for each risk-homogeneous borrower’s group. The modified version of the methodology for assessing individual creditworthiness is presented, which is to reduce the credit risks and to increase the stability and profitability of financial organizations.

A new approach to the stability analysis of thawing slopes

1980 ◽  
Vol 17 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Luis E. Vallejo
Keyword(s):  
Stability Analysis ◽  
Water Content ◽  
Pore Water ◽  
Active Layer ◽  
Necessary Conditions ◽  
Mass Movements ◽  
New Approach ◽  
Pore Water Pressures ◽  
The Stability ◽  
Excess Pore

A new approach to the stability analysis of thawing slopes at shallow depths, taking into consideration their structure (this being a mixture of hard crumbs of soil and a fluid matrix), is presented. The new approach explains shallow mass movements such as skin flows and tongues of bimodal flows, which usually take place on very low slope inclinations independently of excess pore water pressures or increased water content in the active layer, which are necessary conditions in the methods available to date to explain these movements.

scholarly journals INTEGRAL TRANSFORM TECHNIQUE FOR MESON WAVE FUNCTIONS

1996 ◽  
Vol 11 (20) ◽  
pp. 1611-1626 ◽  
Author(s):  
A.P. BAKULEV ◽  
S.V. MIKHAILOV
Keyword(s):  
Wave Function ◽  
Sum Rules ◽  
Integral Transform ◽  
Wave Functions ◽  
Sum Rule ◽  
New Approach ◽  
Exactly Solvable ◽  
The Stability ◽  
The Masses ◽  
Integral Transform Technique

In a recent paper1 we have proposed a new approach for extracting the wave function of the π-meson φπ(x) and the masses and wave functions of its first resonances from the new QCD sum rules for nondiagonal correlators obtained in Ref. 2. Here, we test our approach using an exactly solvable toy model as illustration. We demonstrate the validity of the method and suggest a pure algebraic procedure for extracting the masses and wave functions relating to the case under investigation. We also explore the stability of the procedure under perturbations of the theoretical part of the sum rule. In application to the pion case, this results not only in the mass and wave function of the first resonance (π′), but also in the estimation of π″-mass.

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 INVESTIGATION OF THE GEOMECHANICAL STATE OF SOFT ADJOINING ROCKS UNDER PROTECTIVE CONSTRUCTIONS

2021 ◽  
Vol 36 (4) ◽  
pp. 61-71
Author(s):  
Serhii Nehrii ◽  
Tetiana Nehrii ◽  
Oksana Zolotarova ◽  
Serhii Volkov
Keyword(s):  
Physical And Mechanical Properties ◽  
New Approach ◽  
Soft Rocks ◽  
The Face ◽  
Geomechanical State ◽  
Rock Mass Failure ◽  
The Stability ◽  
Seam Mining ◽  
Mine Roadways

The conditions of coal seam mining in the mines of Ukraine have been considered. The problem of conducting coal mining by longwalls in the conditions of soft adjoining rocks, which concerns the protection of mine roadways located near the face, has been revealed. In such conditions, the existing protective constructions are ineffective due to the fact that they yield and get pressed into the soft rocks of the footwall. This indicated the need for research into the geomechanical state of soft rocks of the footwall. According to the results of known studies on the mechanism of rock mass failure around roadways and the data of physical and mechanical properties of the coal mass, which is represented by soft rocks, the correlation dependence has been obtained, the use of which allowed for the determination of the parameters of the rock deformation diagram and the establishment of the stability criterion of footwall rocks under the protection means and stability conditions of the geotechnical system “protective construction – adjoining rocks.” They are the basis of a new approach to ensure the stability of the roadways, which are supported behind the faces, by controlling the stress state in the system “protective construction – adjoining rocks.” This may be the basis for the development of new methods of protecting roadways in conditions of soft adjoining rocks.

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.

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