AC Electrothermal Pumping Improvement by Biocompatible Nanocomposite Surface Modification

2013 ◽  
Author(s):  
Nazmul Islam ◽  
Davood Askari
Keyword(s):  
Surface Modification ◽  
Biomedical Applications ◽  
Lab On A Chip ◽  
Hydrophobic Surface ◽  
Glucose Sensors ◽  
Electrode Arrays ◽  
Time Intervals ◽  
Pumping Rate ◽  
Regular Time ◽  
Fluid Manipulation

The AC electrothermal effect can improve the pumping rate by multiple folds compared to other eletrokinetic techniques in micro/nano scale. In this research, the AC electrothermal micropump velocity will be optimized by surface modification using a biocompatible hydrophobic nanocomposite monolayer. This coating will modify the micropump surface to a hydrophobic surface and reduce the friction losses at the liquid-solid interface, and eventually increase the micropumping velocity. The advent of microfabrication and integrated miniature pumps has applications on biomedical devices such as implantable glucose sensors. These micropumps require the transport of small amounts of fluids (μL range). When utilized in biomedical applications, micropumps can be used to administer small amounts of medication (e.g. insulin) at regular time intervals. These micropumps can also be integrated with the lab-on-a-chip devices and can provide inexpensive disposable devices. To demonstrate the fluid manipulation in high conductive bio-fluids, we have developed an optimized AC electrothermal micropump using symmetrical electrode arrays.

AC Electrothermal Pumping for Medical Applications

2013 ◽  
Author(s):  
Nazmul Islam
Keyword(s):  
Electric Fields ◽  
Biomedical Applications ◽  
Electrode Arrays ◽  
Ac Electroosmosis ◽  
Time Intervals ◽  
Pumping Rate ◽  
Space Charges ◽  
Regular Time ◽  
Microchip Fabrication ◽  
Fluid Manipulation

While AC electroosmosis (AC-EO) micropumps have advantages of easy implementation and compatibility with microchip fabrication, it has been observed that the pumping rate is decreased for high conductive bio-fluids [1]. To expand our applications to biomedical area we propose here the AC electrothermal (ACET) effect, which can also improve the pumping rate by multiple fold compare to AC-EO. When utilized in biomedical applications, these micropumps can be used to administer small amounts of medication (e.g. insulin) at regular time intervals. ACET generates temperature gradients in the fluids, and consequently induces space charges that move in electric fields and produce microflows. To demonstrate the fluid manipulation in high conductive bio-fluids, we have developed an AC electrothermal micropump using asymmetrical electrode arrays.

scholarly journals Water uptake of various electrospun nonwovens

2020 ◽  
Vol 6 (3) ◽  
pp. 155-158
Author(s):  
Katharina Wulf ◽  
Volkmar Senz ◽  
Thomas Eickner ◽  
Sabine Illner
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Water Absorption ◽  
Water Uptake ◽  
Biomedical Applications ◽  
High Surface ◽  
Volume Ratio ◽  
Polymer Composition ◽  
Water Wetting ◽  
Morphology Changes

AbstractIn recent years, nanofiber based materials have emerged as especially interesting for several biomedical applications, regarding their high surface to volume ratio. Due to the superficial nano- and microstructuring and the different wettability compared to nonstructured surfaces, the water absorption is an important parameter with respect to the degradation stability, thermomechanic properties and drug release properties, depending on the type of polymer [1]. In this investigation, the water absorption of different non- and plasma modified biostable nanofiber nonwovens based on polyurethane, polyester and polyamide were analysed and compared. Also, the water absorption by specified water wetting, the contact angle and morphology changes were examined. The results show that the water uptake is highly dependent on the surface modification and the polymer composition itself and can therefore be partially changed.

scholarly journals Topographical and Biomechanical Guidance of Electrospun Fibers for Biomedical Applications

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2896
Author(s):  
Sara Ferraris ◽  
Silvia Spriano ◽  
Alessandro Calogero Scalia ◽  
Andrea Cochis ◽  
Lia Rimondini ◽  
...  
Keyword(s):  
Surface Modification ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Electrospun Fibers ◽  
Natural Polymers ◽  
Polymeric Fibers ◽  
Biological Phenomena ◽  
Proper Design ◽  
Synthetic And Natural Polymers ◽  
Selection Of

Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.

scholarly journals Speech rhythm: a metaphor?

2014 ◽  
Vol 369 (1658) ◽  
pp. 20130396 ◽  
Author(s):  
Francis Nolan ◽  
Hae-Sung Jeon
Keyword(s):  
Traditional View ◽  
Time Intervals ◽  
Speech Rhythm ◽  
Linguistic Structure ◽  
Regular Time ◽  
Linguistic Functions ◽  
Absence Of Evidence ◽  
Metaphorical Extension ◽  
Analogical Process

Is speech rhythmic? In the absence of evidence for a traditional view that languages strive to coordinate either syllables or stress-feet with regular time intervals, we consider the alternative that languages exhibit contrastive rhythm subsisting merely in the alternation of stronger and weaker elements. This is initially plausible, particularly for languages with a steep ‘prominence gradient’, i.e. a large disparity between stronger and weaker elements; but we point out that alternation is poorly achieved even by a ‘stress-timed’ language such as English, and, historically, languages have conspicuously failed to adopt simple phonological remedies that would ensure alternation. Languages seem more concerned to allow ‘syntagmatic contrast’ between successive units and to use durational effects to support linguistic functions than to facilitate rhythm. Furthermore, some languages (e.g. Tamil, Korean) lack the lexical prominence which would most straightforwardly underpin prominence of alternation. We conclude that speech is not incontestibly rhythmic, and may even be antirhythmic. However, its linguistic structure and patterning allow the metaphorical extension of rhythm in varying degrees and in different ways depending on the language, and it is this analogical process which allows speech to be matched to external rhythms.

Hydrophobic surface modification of FMSS and its application as effective sorbents for oil spill clean‐ups and recovery

AIChE Journal ◽  
2017 ◽  
Vol 63 (9) ◽  
pp. 4090-4102 ◽  
Author(s):  
Oluwasola Oribayo ◽  
Qinmin Pan ◽  
Xianshe Feng ◽  
Garry L. Rempel
Keyword(s):  
Surface Modification ◽  
Oil Spill ◽  
Hydrophobic Surface

Processing and Excellent Oxidation Resistance of Nanocrystalline Fe-Cr Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 1122-1125
Author(s):  
Rajeev K. Gupta ◽  
B.V. Mahesh ◽  
R.K. Singh Raman ◽  
Carl C. Koch
Keyword(s):  
Oxidation Resistance ◽  
Secondary Ion Mass Spectrometry ◽  
Nanocrystalline Alloy ◽  
High Energy ◽  
Processing Route ◽  
Protective Oxide ◽  
Time Intervals ◽  
Regular Time ◽  
Order Of Magnitude ◽  
Energy Ball

Nanocrystalline and microcrystalline Fe-10Cr alloys were prepared by high energy ball milling followed by compaction and sintering, and then oxidized in air for 52 hours at 400°C. The oxidation resistance of nanocrystalline Fe-10Cr alloy as determined by measuring the weight gain after regular time intervals was compared with that of the microcrystalline alloy of same chemical composition (also prepared by the same processing route and oxidized under identical conditions). Oxidation resistance of nanocrystalline Fe10Cr alloy was found to be in excess of an order of magnitude superior than that of microcrystalline Fe10Cr alloy. The paper also presents results of secondary ion mass spectrometry of oxidized samples of nanocrystalline and microcrystalline Fe-Cr alloys, evidencing the formation of a more protective oxide scale in the nanocrystalline alloy.

Sign in / Sign up

Export Citation Format

Share Document