17 research outputs found
The Effects of Additives on the Physical Properties of Electroformed Nickel and on the Stretch of Photoelectroformed Nickel Components
The process of nickel electroforming is becoming increasingly important in
the manufacture of MST products, as it has the potential to replicate complex
geometries with extremely high fidelity. Electroforming of nickel uses
multi-component electrolyte formulations in order to maximise desirable product
properties. In addition to nickel sulphamate (the major electrolyte component),
formulation additives can also comprise nickel chloride (to increase nickel
anode dissolution), sulphamic acid (to control pH), boric acid (to act as a pH
buffer), hardening/levelling agents (to increase deposit hardness and lustre)
and wetting agents (to aid surface wetting and thus prevent gas bubbles and
void formation). This paper investigates the effects of some of these variables
on internal stress and stretch as a function of applied current density.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Poly(4-vinylaniline)/polyaniline bilayer functionalized bacterial cellulose membranes as bioelectronics interfaces
Bacterial cellulose (BC) fibers are chemically functionalized with poly(4-vinylaniline) (PVAN) interlayer for further enhancement of electrical conductivity and cell viability of polyaniline (PANI) coated BC nanocomposites. PVAN is found to have promoted the formation of a uniform PANI layer with nanofiber- and nanorod-like supramolecular structures, as an overall augmentation of PANI yield. Compositional and microstructural analysis indicates a PVAN/PANI bilayer of approximately 2 μm formed on BC. The solid-state electrical conductivity of such synthesized BC nanocomposites can be as high as (4.5 ± 1.7) × 10−2 S cm−1 subject to the amounts of PVAN chemically embraced. BC/PVAN/PANI nanocomposites are confirmed to be thermally stable up to 225 °C, and no signs of cytotoxicity for SVZ neural stem cells are detected, with cell viability up to 90% on BC/PVAN/PANI membranes. We envisage these new electrically conductive BC/PVAN/PANI nanocomposites can potentially enable various biomedical applications, such as for the fabrication of bioelectronic interfaces and biosensors
Processing and Characterization of Precision Microparts from Nickel-based Materials
The objective of this research was to study the influence of electroplating parameters on electrodeposit characteristics for the production of nickel (Ni) and nickel-iron (Ni-Fe) microparts by photoelectroforming. The research focused on the most relevant parameter for industry, which is the current density, because it determines the process time and the consumed energy. The results of the Ni and Ni-Fe characterisations can be divided into two aspects closely linked with each other ; the morphology and the hardness
Effects of channel surface finish on blood flow in microfluidic devices
The behaviour of blood flow in relation to microchannel surface roughness has
been investigated. Special attention was focused on the techniques used to
fabricate the microchannels and on the apparent viscosity of the blood as it
flowed through these microchannels. For the experimental comparison of smooth
and rough surface channels, each channel was designed to be 10mm long and
rectangular in cross-section with aspect ratios of â ¥100:1 for channel heights of
50 and 100μm. Polycarbonate was used as the material for the device
construction. The shims, which created the heights of the channels, were made of
polyethylene terephthalate. Surface roughnesses of the channels were varied from
Rz of 60nm to 1.8μm. Whole horse blood and filtered water were used as the test
fluids and differential pressures ranged from 200 to 5000Pa. The defibrinated
horse blood was treated further to prevent coagulation. The results indicate
that a surface roughness above an unknown value lowers the apparent viscosity of
blood dramatically due to boundary effects. Furthermore, the roughness seemed to
influence both water and whole blood almost equally. A set of design rules for
channel fabrication is also presented in accordance with the experiments
performed
Effects of channel surface finish on blood flow in microfluidic devices
The behaviour of blood flow in relation to microchannel surface roughness has been investigated. Special attention was focused on the techniques used to fabricate the microchannels and on the apparent viscosity of the blood as it flowed through these microchannels. For the experimental comparison of smooth and rough surface channels, each channel was designed to be 10mm long and rectangular in cross-section with aspect ratios of ⊵100:1 for channel heights of 50 and 100μm. Polycarbonate was used as the material for the device construction. The shims, which created the heights of the channels, were machined from poly(ethylene terephthalate). Surface roughnesses of the channels were varied from Rz of 60nm to 1.8μm. Whole horse blood and filtered water were used as the test fluids and differential pressures ranged from 200 to 5000 Pa. The defibrinated horse blood was further treated to prevent coagulation. The results indicate that a roughness above an unknown value lowers the apparent viscosity of blood dramatically due to boundary effects. Furthermore, the roughness seemed to influence both water and whole blood almost equally. A set of design rules for channel fabrication is also presented in accordance with the experiments performed. ©EDA Publishing/DTIP 2009
Effects of channel surface finish on blood flow in microfluidic devices
The behaviour of blood flow in relation to microchannel surface roughness has been investigated. Special attention was focused on the techniques used to fabricate the microchannels and on the apparent viscosity of the blood as it flowed through these microchannels. For the experimental comparison of smooth and rough surface channels, each channel was designed to be 10mm long and rectangular in cross-section with aspect ratios of ⊵100:1 for channel heights of 50 and 100μm. Polycarbonate was used as the material for the device construction. The shims, which created the heights of the channels, were machined from poly(ethylene terephthalate). Surface roughnesses of the channels were varied from Rz of 60nm to 1.8μm. Whole horse blood and filtered water were used as the test fluids and differential pressures ranged from 200 to 5000 Pa. The defibrinated horse blood was further treated to prevent coagulation. The results indicate that a roughness above an unknown value lowers the apparent viscosity of blood dramatically due to boundary effects. Furthermore, the roughness seemed to influence both water and whole blood almost equally. A set of design rules for channel fabrication is also presented in accordance with the experiments performed. ©EDA Publishing/DTIP 2009
Fabrication of a free standing resolution standard for focusing MeV ion beams to sub 30 nm dimensions
10.1016/j.nimb.2005.01.052Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms2311-4170-175NIMB