Thursday, March 31, 2011

Remembering 2010 Iceland Volcanic Ash


DATE FRIDAY 16, 2010. TIME 16 HOURS

START FROM GOTHENBURG SWEDEN TO LONDON UK.

ENTERING DENMARK

ENTERING GERMANY

ENTERING NETHER LAND

ENTERING BELGIUM

ENTERING FRANCE- DIRECT TO Z1 DU PORT DUNKERQUE

ENTERING UK- DOVER PORT TO DOVER TRAIN STATION

REACH ST. PANCRAS INTERNATIONAL ON SATURDAY 17. 2010 8.30 HOURS. 1600KM

l AM BEING HOLD BY BRITISH M16 OUTSIDE ST. PANCRAS INTL TRAIN STATION

SUSPECTED ME AS TERRORIST, BUT THEN THEY LET ME GO SINCE I GOT NOTHING ON ME . MEET ENGLAND PM GORDON BROWN OUT SIDE THE TRAIN STATION.

PM IS ON HIS ELECTION CAMPAIGN VISITING PUBLIC AT THE TRAIN STATION.

ALL BECAUSE OF VOLCANIC ASH FROM ICELAND.

Saturday, March 26, 2011

SPR Navi 200 specification


SPR Navi 200 specification
1. True goniometric principle, enabling to record the full SPR curve for thickness and refractive index model-ing
2. Wide SPR angle range (40 degrees to 78 degrees) allowing to measure both liquid and gas samples with the same instrument
3. Proprietary SPR slide holder allowing easy change and use of SPR gold slides
4. Easy drop-in action in placing the SPR slide in the instrument
5. Easily removable and easily customizable flow cell
6. Modular design allowing to add an autosampler and other features, such as multi wavelength function, at the later stage
7. No need to use messy and inconvenient index matching oil because of the proprietary index matching gel
8. Open design allowing the customer use their own fluidics and flow control (our pump can easily be by-passed)
9. Build in peristaltic pump and optional syringe pump available
10. Easy to use slide holder allowing quick and easy slide replacement without any tools
11. External immobilizer allowing the instrument be used while immobilizing the gold surfaces
12. Possibility to use two lasers with different wave lengths and/or even IR lasers
13. Optional electrochemistry flow cell

Thursday, March 24, 2011

Contact Angle meter/Gonimeter: Theory




Contact Angle: Theory

The following is a short introduction to the concepts involved in the measurement of contact angles. Included is an introduction to the techniques involved and some practical advise. For those interested in further information a list of references appears at the end of this chapter.

What is contact angle?
Contact angle ,q, is a quantitative measure of the wetting of a solid by a liquid. It is defined geometrically as the angle formed by a liquid at the three phase boundary where a liquid, gas and solid intersect.

It can be seen from this figure that low values of q indicate that the liquid spreads, or wets well , while high values indicate poor wetting. If the angle
q is less than 90 the liquid is said to wet the solid. If it is greater than 90 it
is said to be non-wetting. A zero contact angle represents complete wetting.

Hysteresis: For any given solid / liquid interaction there exists a range of contact angles which may be found. The measurement of a single static contact angle to characterize the interaction is no longer thought to be adequate. The value of static contact angles are found to depend on the
recent history of the interaction. When the drop has recently expanded the angle is said to represent the ‘advanced’ contact angle. When the drop has recently contracted the angle is said to represent the ‘receded’ contact angle. These angles fall within a range with advanced angles approaching a maximum value and receded angles approaching a minimum value.
The difference between the maximum(advanced) and minimum(receded) contact angle values is called the contact angle Hysteresis. A great deal of research has gone into analysis of the significance of hysteresis. It has been used to help characterize surface heterogeneity, roughness and mobility. You are recommended to the papers listed in the reference of this section for details on experiments regarding hysteresis.
Contact angle can also be considered in terms of the thermodynamics of the materials involved. This analysis involves the interfacial free energies between the three phases and is given by:

glv cos q = gsv - gsl
where glv ,gsv and gsl refer to the interfacial energies of the liquid/vapor, solid/vapor and solid/liquid interfaces.
Coatings: Coatings may be applied to any solid for testing contact angles. Microscope slides and cover slips make ideal supports for such an application. Ideally the coating should be applied to all sides. If you reduce the size of your sample by cutting after coating you will expose part of the support which is not coated. This will introduce an error in your data especially if the cut side is rough. Your data may be consistent enough to compare between similarly treated samples but the absolute values will not be accurate.