The conceptual design of a harvesting device for obtaining taxanes in a sustainable way

•

~

T

U

Delft

DELFT UNIVERSITY OF TECHNOLOGY

The conceptual design of a

harvesting device

for obtaining taxanes in a sustainable way

APPENDICES

November 7,2008

Students: Fabienne Goosens

1168061

Reina van Houten

1185055

Gerdien de Jong

1392719

Marloes Reus

1148885

Haohao Zhu

1388223

Supervisors: Prof.dr.ir. p.w. Appel

Ir. P.l.J. Swinkels

Or. Ir. J.C.M. Marijnissen

Appendix A

.

Biology

In this appendix, other compounds present in yew trees, together with taxa nes, are visible. Table A-1 gives an overview of the research of Theodoridis et al.1, in which an extract of T. Baccata needies was analyzed using RP-HPLC. Quantitation of absorbance was accomplished at wavelengths of 227, 249 and 280 nm. Ratioing these absorbances was used as a tooi for identification of different kinds of substances, like taxa nes or taxi nes. m/z is the mass divided by the charge of the corresponding ions, which was needed for a positive identification of a certain compound, together with the absorbance ratios and residence times. Compounds 1-9 are known taxi nes, predetermined in former experiments. Taxines have a similar structure to taxanes, but have different side chains to the ring structure, compared to taxanes. 10-DAB was the only taxane positively identified by the

m/z

ratio. The other taxa nes are determined to be taxa nes, but which ones they were was not positively determined. The Ut compounds are established to be taxi nes, however, they are unknown. Together with these compounds, some unknown (U) compounds Were detected as weil.

Table A-l Chromatographic data obtained after the LC-PDA and LC-MS analysis of the purified taxine mixture on a Luna Column

Compound tR (min)

A227/A249 A227/A280 A249/A280

m/z

Taxane 13.5 3.57 10.66 2.96 N/Dt 10 DAB 111 15.5 2.53

10044

4.12 545 Taxane 17.0 3.80 10.12 2.78 N/Dt Taxane 18.5 4.17 24.20 5.80 N/Dt

Ut

18.8 N/Dn N/Dn N/Dn 612

U

19.2 3.26 N/Dn N/Dn 604 Taxane 20.3 3.22 15.10 4.72 584

U

2204

1.16 13.10 11.36 584 2 24.5 2.03 0.93

0046

568 1

2504

1.62 1.08 0.66 542

3

25.8 1.21 1.10 0.92 626

Ut

25.8 N/Dn N/Dn N/Dn 642 5 26.8 1.60 1.12 0.66 568

Ut

2704

N/Dn N/Dn N/Dn 628

Ut

27.7 1.97 0.94

0048

584

Ut

29.6 1.30 2.25 1.73 628 4

3004

1.16 1.13 0.98 584 6 31.7 1.28 1.23 0.96 584 7 32.0 1.85 0.93

0047

626

Ut

32.3 3.83 N/Dn N/Dn 610

U

32.6 5.63 3.25 0.57 784 8 33.1 1.75 0.88 0.51 668

1 Theodoridis, G., Laskaris, G., Rozendaal, E.L.M., Verpoorte, R., (2001), Analysis of Taxines in Taxus plant material and cell cultures by HPLC photodiode array and HPLC electrospray mass Spectrometry, J. LlQ. CHROM. & REL. TECHNOL., 24(15), 2267-2282 (2001)

Ut

33.6

1.75

0.90

0.50

612

Ut

36.5

1.44

0.32

0.45

668

Ut

37.0

1.90

0,45

0.32

610

Ut

38.9

3.77

1.19

0.31

654

Ut

39.5

2.18

1.02

0.47

610

9

41,4

1.88

1.50

0.80

652

Ut

41.9

N/Dn N/Dn N/Dn

668

U=Unknown, Ut = Unknown 'Taxine', N/Dt = Not Detected, N/Dn = Not Determined

Appendix B.

New Proposals

In th is appendix, section B-1, the results of a brainstorm session for new methods to obtain taxanes are visible. In section B-2 a graph can be seen of the vapor pressure vs. the temperature of methanol, which is used to clarify one of the new proposals for harvesting taxanes.

B-1

Brainstorm

Brainstorm session of 11 September 2008 for generating ideas for winning taxanes:

~ Expeller/press ~ extrusion ~ Rupture of cell by ultrasound

~ Solvent extraction from removed ~ (Vacuum) suction

needies ~ Trigger by changing cell environment

~ Solvent extraction when needies are ~ Open needie with enzymes/ chemical

on tree reaetion

~ Full synthesis ~ Rupture of cell by laser

~ Electrospray ~ electric field ~ Rupture of cell by heat

-7

boiling

~ Cell culture ~ Rupture of cell by UV light

~ Supercritical fluid ~ Rupture of cell by freezing

~ Simulate animal attack ~ Rupture of cell by pressure

-7

turgor

0 Chemical ~ Rupture of ce 11 by osmosis

-7

lot of

0 "Jaws"

=

mechanical chewing water uptake

-7

break cells

~ Fungi! bacteria ~ Rupture of cell by drying

The above mentioned ideas can be divided into four groups; the ways in which taxa nes can be obtained:

~ Cell culture

-7

not of our interest

~ Fungi! bacteria ~ not of our interest

~ Chemical synthesis

-7

is a process, very low yield, not commercially doable ~ Extraction from trees

Taxanes degrade under influence of light and heat, 50 rupture of the cell by a laser, heat or UV-light is not an option. Cell rupture by osmosis is not promising either since there does not seem to be a way to increase the concentration in a cell that largely that the cell will rupture.

Getting taxanes from trees can be done either by collecting needies from the tree and taking taxanes from the collected needies, or leaving the needies on the tree and apply some technique to get it out. When needies are removed from the tree to obtain the taxanes the efficiency is low (1 mg taxanes/kg bark), a technique is needed to re move the needies from the tree and another method is needed to get the taxanes out of the needies. It would be better to Ie ave the needies on the tree, since it is more practical and will induce lower costs.

The options that remain after crossing out the less promising ideas of the initiallist are:

~ Solvent extraction

~ Supercritical fluid

~ (Vacuum) suction

~ Electrospray ~ electric field

By these techniques, the harvesting of the taxanes is supposed to happen .while the needies remain on the tree.

•

B

-

2

Methanol evaporation

One of the options of to get taxanes out of yew trees is solvent extraction. It was found that methanol can be a suitable solvent. The way of gaining pure taxanes from the extract is to evaporate the methanol from the taxanes. This can be done by either increasing the temperature or lowering the pressure. Taxanes degrades rapidly at higher temperatures and to prevent this the methanol can be evaporated by vacuum evaporation. A suitable temperature and pressure combination can be found from Figure B-12, in which the vapor pressure of methanol is plotted versus the temperature. From th is graph it is visible that for example at 0.04 bar a temperature of SOC is high enough for methanol to evaporate.

I

m m

g

1

.L f) ":j ClU

I

I

0 ~u

I

I

I fJU

_I

v r-'V

/

I

J IU

/

I V

/

/

.;) IlJ

V

..,

.r>

/

V

.,..

/

oL IV

L

V

/ "

0

~o EO

ot:

---

lO

Figure B-1 Methanol vapour pressure (y) vs. temperature (x)

2 Material data sheet, Methanol, Vapor pressure of Iiquid,

B-3

Amount and composition

ot

product

trom

electrospraying

Unfortunately, there is not much data available about the amount and composition of the product obtained from electrospraying yew trees. There is one data set on hand from one experiment performed by Dr. Ir. Marijnissen where the composition of the droplets obtained byelectrospraying from a yew tree was analyzed. In this experiment 5.5 ng baccatin 111 and 26.4 ng 10-deacetylbaccatin 111 was obtained. The total amount of these two precursors in the needie was also detected. Paclitaxel was not found even though the concentration of paclitaxel is almost three times as high as the concentration baccatin 111 in the needies of the

Taxus Baccata,

the species where the experiment was performed on. Other taxanes, besides the three mentioned above, were not detected in the analysis. A summary of the results can be found in Table B-13•

Table 8-1 Difference in selectivity between two precursors obtained byelectrospraying

Compound Obtained by electro- Obtained byextraction Percentage obtainable

spraying 3 single electrospray

treatment

Baccatin 111 5.5 ng 647 ng 1%

10-deacetyl baccatin 111 26.4 ng 39260 ng 0.1%

The results show selectivity for the release of baccatin 111 over 10-deacetyl baccatin 111. The research group is soon going to analyze new electrospray samples4. For now, the assumption is made th at 1% of the total amount of taxa nes present in the needie can be removed by one electrospray trial, since there seems to be no explanation for selectivity. The taxa nes are expected to be transported in colloidal farm, however it is questionable if the baccatin III colloid is remarkable different th at a 10-deacetyl baccatin 111 colloid, since both molecules consist of the same structure except one side-group (acetoxy side-group vs. alcohol). It is thought that this has no significantly affect on the mobility of the colloid, and that there is no reason for one of the compounds to form colloids easier than the other compound, and that therefore the percentage of taxanes obtained by electrospraying is equals.

3 Marijnissen, J.C.M., van Dam, J., Roos, R., (2001), Npt-wetenschapskatern, 'Milking' Trees for Medicines, Npt

procestechnologie, 8, 22-24.

4 Yurteri, Dr. C.U., Visiting Scientist, NanoStructured Materiais, TU Delft, Personal communication,

September-October, ,2008.

S Koper, Dr. Ing. G.J.M., DCT/Self-Assembling Systems, TU Delft, Personal communication,

September-October, 2008.

•

Appendix C.

Electrospray

Electrospray was chosen as method for a new design of a taxane harvesting device. In th is appendix calculations are shown which are used for the modeling of the electrospray from the needies. In Section C-1, the maximum concentration of taxa nes in the needies is calculated, in Section C-2 the velocity of ions moving in the needies due to the electric field is calculated. In Section C-3, the forces on the cone jet are identified, in Section C-4 the model assumptions are stated and explained. In Section C-5 extended calculations are shown for determining the flow rate from one needie, the droplet si ze, the charge on a droplet and the electric field strength around a droplet, and in Section C-6 the results of the model calculations are put in an excel file.

C-1

Calculating maximum concentration of taxa nes in

needies

The screening of needies of different yew species done by van Rozendaal6 showed the different concentration taxanes in the needies of different yews species. The highest concentrations of the three taxanes paclitaxel, baccatin lil, and 10-deacetylbaccatin 111 where taken and converted to the unit mg/ml to be able to compare them with the maximum solubility given in literature (see Table C-1).

Table C-1 Maximum concentration of three taxanes converted from IJgfg dried needies to mgfml. Compound Max. concentration Calculated max.

found in yew needies concentration found in in Ilg/g dried needles6 needie

Paclitaxel 516 0.28 mg/ml

Baccatin 111 296 0.16 mg/ml

10-deacetyl 2665 1.4 mg/ml

baccatin 111

By the conversion it was assumed that the needie has a 35 wt% dry mass and that the concentration ofTaxol is homogeneous inside the needie. The following conversion was used:

flg

= 0

.

35 g dried mass

*

1

g

wet needIe

*

10-

3

g

=5.38*10-4 mg

g

dried needle

0.65 g wet needIe

1

mL

water

lflg

mL

With the concentration in mg/ml, the values could be compared with the maximum solubility of the taxanes in water to see whether the taxanes are just dissolved in the aqueous phase in the needie, or that there has to be a mechanism to increase the solubility, since taxa nes present in solid phase is not likely.

6 van Rozendaal, E.L.M., Lelyveld, G.P., van Beek, T.A., (2000), Sreening of the needies of different yew species and cultivars for pac1itaxel and related taxoids, Phytochemistry, 53, 383-389.

- - - _ .. _--- - -- - -- -- - -

-Velocity of ions when inducing an electric fieldThe speed of an ion in an electric field can be

calculated in the following way:

~

Electric field:

~-l-Where E is the electric field strength in V

jm

or NjC, ~<I> is the potential difference in V, and I is the

distance between the electrode and the ion in m.

Force on ion due to the electric field:1

F

E

=

qE

I

Where FE is the force due to the electric field in N, and q is the charge in C.

Drag force:

I

F

drag =

6n-a17v

l

Where Fdrag is the drag force in N, a is the radius of the ion in m, 11 is the dynamic viscosity in Pa·s, and

v is the velocity of the ion in

mis

.

lonic mObility:lu =

q

I

6na17

Where u is the ionic mobility in m2jsV

F

E

=

F

drage

Force balance:

qE

=

6n-a17

v

v

=uE

lonic mobilities, u, are in the order of 10.7 to 10.8

m

2

/sV

.

Below is a short list of the mobilities of the most important ions in water of 25°(.7

2 H+ =

36.23

*

lO

-

s

~

sV

2 Na+

=5

.

19

*

10

-

S

~

sV

2

K+

=7.62

*

10

-S

~

s

V

2

OH

-

=

20

.64

*

10

-

s

~

s

V

2

c

r

=7

.

91

*

10-

S

~

s

V

Taking the ion with the lowest mobility from the list, Na·, by an electric field strength of 4000 V and a distance of 3 cm, the velocity was calculated to be 0.01

mis

.

Assuming the width of the needie is 2 mm, the estimated time to for all the ions to reach equilibrium after inducing electric field is about 0.3 seconds.

(-2

Farces on cone-jet

The movement of the sap inside the needie that is enforced by the electric field is counteracts by capillary forces. Once the electric forces overcome the capillary forces the transport takes place.

Since at the tip of the needie the electric field strength is the highest, and the needie is shapely pointed, at this tip the spraying can be started. The force balance of the electrospraying in cone-jet mode is shown in Figure (-1.

TUICDtial Electric Sire ••

Elcctric POlarizatiOD Sire ..

Figure C-1 Forces acting on liquid in external electric fields

7 Hartman, R.PA et al. (2000). Jet break-up in electrohydrodynamic atomization in the cone-jet mode. Journal of Aerosol Science, Volume 31, No. 1, pp. 6S-9S

S Ciach, T., Geerse, K.B., Marijnissen, lC.M., 2004, EHDA in ParticIe Production, Application of electrospray in

In the absence of electric field and the present of a liquid flow dripping takes place. By the induction of an electric field, the normally half-circled shaped meniscus changes to a cone shape. This cone is called the Taylor cone. Under steady state conditions, there is a balance between the normal and tangential electric stress, surface tension, gravity, viscosity, and electric polarization stress. At steady state, liquid flows to the tip of the Taylor cone and forms a jet. The jet is broken up by one of the two instability mechanisms, the varicose or the kink instability, and forms a fan of fine droplets8.

C-3

Assumptions

tor

electrospray model

Many assumptions had to be made in order to be able to model the electrospraying process. In the coming paragraphs these assumptions are explained in the same order as listed in the report.

The drop let has the properties of water

It is assumed that the droplet has the properties of water, since the exact composition of the droplet right after leaving the needie is unknown. It is known that a needie consists of 65% water, and it is thought that initially the droplet also contains around 90% of water4• To simply the model, for the

calculations the properties of pure water are used.

No evaporation of the droplet takes place and all droplets have the same size

During the flight of the droplet from the needie to the collecting bag, some water from the droplet will evaporate. To prevent complex modelling about the evaporation rate and droplet size, it is assumed th at no evaporation takes place. The assumption is made that all the droplets have the same size. It is known that by electrospraying, the droplets sizes distribution is not that wide9, and to prevent to model with different droplet sizes th is assumption is made.

The charge on the droplet is constant, e.g. there is no discharge during the flight

Since it is assumed that no evaporation of the droplet takes place, the charge concentration of the droplets will stay the same. Discharge of the droplets is not take into account because no numbers about the charge loss due to discharge could be found, and it is thought th at this number is relatively small and th at it therefore could be neglected.

20% of the sap in the needie can be removed in 20 min

It is assumed that 20% of the sap in the needie can be removed while keeping the nee die alive and that the electrospraying takes place over a time span of about 20 min. After 20 min. the needie stops spraying. This information is obtained from an expert in the field of electrospraying on treeslO.

9 Geerse, K. B. (2003), Applications of Electrospray: From people to plants, TU Delft, May 20, 2003.

10 Ursem, Drs. W.N.J. Scientific director Botanical Garden Delft, Personal communication, September 23, 2008.

•

Electric field attraction force and drag force are the main forces; the gravitational force and the Coulomb interaction forces can be neglected

The electric field force and the drag force have the most influence on the movement of the droplets. The gravitational force is more than 106 smaller than electric attraction force, therefore it is justified to neglect this force. The Coulomb interaction force is also relatively small9 so it can be neglected (see Appendix C-6).

The air velocity around the electrospray is zero

When the velocity of the droplets is sufficiently high, the air velocity can become important for the break up point of the jet. According to Hartman e.a., when a cone-jet is produced with typical values, (rjet

=

5.10.6 m, jet velocity

=

20

mis,

y

=

0.03

Nim,

and Pgas

=

1.2

kg/m

3

), the influence on the growth

rate is only about 4%7. By electrospraying from the needies, it is thought to have typical values and therefore the velocity of air around the spray is neglected.

(-4

Extended calculations

C-4.a Extended caJculation about determininq the flow rate (rom one needIe

The weight of the needies was determined by counting 177 needies that were obtained from various yew hedges in the neighbourhood of the Delft ChemTech building in Delft. The weight was found to be 4.140 g, which gives an ave rage of 0.023 g per needie.

The moisture content in a needie is 65%11, and the amount of water per needie is therefore 0.015 g.

20% is the maximum amount that can be removed from a needie while still keeping it alive. 20% of 0.015 g is 0.003 g water per needie, which is equal to 0.003 mi or 3

111.

The time span over which the spraying takes place is 20 min., and this give 9 Ill/h.

C-4.b Extended caJculation about determininq the droplet size

The droplet size was calculated from the flow rate

Where dis the droplet size in m, PI is the density of water in

kg/m

3

, Eo is the permittivity of free space

C2

IN

m2, Q is the flow rate m3/hr, y is the liquid surface tension of water in

Nim,

and K is the electric

conductivity in

Slm

.

In Table C-2, the values for the different constants are given.

11 EISohly, H.N., Croom, E.M., Jr., Kopychi, W.J., Joshi, A.S., EISohly, M.A., McChesney, J.D. (1995),

Concentrations of Taxol and related taxanes in the needies of different Taxus cultivars, Phytochem. Anal. 6,

Table C-2 Values tor different constants

Constant Value

PI, the densitv of water 1000 kg/m3

Eo, the permittivitv of free space 8,85.10'12 C2/Jm 9

V, the liquid surface tension of water 0.07275 Nim 12 K, is the electric conductivitv 0.00805 Slm 13

Putting the information above into the equation gives:

I

d

=

16

*

1000

k

~

*

8.8

5

*10

-

1

2

~

*

(4

*

10

-

1

2

m

3

J

3 6

m

Jm

s

=5

*

1O

-7

_m

0

.

07275 N

*

0.00805

~

m

m

C-4.c Extended calculation about determining the charge on a droplet

The maximum charge on a droplet can be calculated in the following waV:

q

m

ax

=

1r~

8

ë

o

rd

3

.---q

max

=1r

8

*

8.85

*

10-12

~

*

0.07275N

*

(5

*

10

-7

m

)

3

=2

.

5*10

-

15

_C

Jm

m

drop/

et

where qmax is the maximum charge of the droplet, Eo is the permittivitv of free spa ce, y is the liquid surface tension of water, and d is the droplet size.

The droplets produced bV electrospraving in the cone-jet mode carry approximate1v 70% of qmax 9,

which is 1.8·1Q-15Cjdroplet.

C-4.d Extended calculation about determining the electric field strength around a droplet

The electric field strength where the droplet moves in, changes once the position to the electrode is different. During the journev of the droplet to the electrode, two main forces are acting on the droplet, name1v the electrical attraction force and the drag force.

The force due to the electrical attraction between the droplet and the electrode is:

F

elect . =

qË

where

F

eIect. is the electrical attraction force, and

Ë

is the electric force at the tip of the needie.

12 Janssen, L.P.B.M., Warmoeskerken, M.M.CG., (1987). Transport Phenomeno Dota Companion. VSSD.

13 Greathouse, G.A., Conductivity Measurements of Plant Sap,

The drag force is described by the following equation:

where

F

Dis the drag force, CD is the drag factor, vair is the air velocity, and Vi is the velocity of the droplet.

The drag factor is dependent on Reynolds number, which can be ca1culated by:

where Ilair is the dynamic viscosity.

R

e

=

_P-"a;....ir.!..IV....::a.c..ir_-_V-,-i.!..1

d_

7]air

It is assumed that the droplet is in the laminar Stokes regime, (Reynolds number smaller than one). In that case, the drag factor can be calculated by the Iinear relation between Re and CD:

C

_D

_ 24

-Re

Models published of the cone-jet spraying gave velocities differences between the droplet and the surrounding air between 12 and 17

mis

9, and 10 to 15

mis

s.

It was found that the electric field strength has to be between 4.9.105 and 8.3.105

Vlm

in order for the droplet to have a velocity different of 10 and 17

mis

with the surrounding air. Since it is assumed that the air velocity is zero, the velocity differences are equal to the velocity of the droplet.

A velocity of the droplet of 17

mis

gives a Reynolds number of 0.6, showing that it was justified to assume that the droplet moves in the laminar regime.

c-s

Model calculations in the excel sheet

Flow rate

Q, flow rate 4,01E-12

m

3

/s

Q, flow rate 1,44E-05 I/h

Q, flow rate 0,01 ml/h

Constants

Properties droplet (based on water)

~, liquid surface tension at 20·C 0,07275 NIm

p water, density water 1000 kg/m3

K, electrical conductivity 0,00805 Slm

d d, droplet size 5,00E-07 m

q max 2,52E-15 C/dropl.

q 1,76E-15 C/dropl.

Assumption

lelectric field strength 8,30E+05Iv Im

Properties air

pair, density air at 20·C 11, dynamic viscosity Drag force

initial guess velocity droplet 10

mIs

I

Re number 0,331

Corresponding Cw, drag coefficient 72,4979

Corresponding velocity when F elec.attr.=F drag 13,07

mIs

_I

Re number 0,433

Corresponding Cw, drag coefficient (laminair) 55,479

Corresponding velocity when F elec.attr.=F drag 14,94 mIs

I

Re number 0,495

Corresponding Cw, drag coefficient (laminair) 48,532

Corresponding velocity when F elec.attr.=F drag 15,97

mIs

I

Re number 0,529

Corresponding Cw, drag coefficient (laminair) 45,391

Corresponding velocity wh en F elec.attr.=F drag 16,51 mIs

_I

Re number 0,547

Corresponding Cw, drag coefficient (laminair) 43,898

Corresponding velocity when F elec.attr.=F drag 16,79 mIs

_I

Re number 0,556

Corresponding Cw, drag coefficient (laminair) 43,170

Corresponding velocity when F elec.attr.=F drag 16,93 mIs

I

Re number 0,561

Corresponding Cw, drag coefficient (laminair) 42,811

Re number 0,563 Corresponding Cw, drag coefficient (laminair) 42,632

Corresponding velocity when F elec.attr.=F drag 17,04 mis

I

Re number 0,564

Corresponding Cw, drag coefficient (laminair) 42,543

Corresponding velocity when F elec.attr.=F drag 17,06 mis

I

Re number 0,565

Corresponding Cw, drag coefficient (laminair) 42,499

Corresponding velocity when F elec.attr.=F drag 17,07 mis

I

Re number 0,565

•

Corresponding Cw, drag coefficient (laminair) 42,477

Corresponding velocity when F elec.attr.=F drag 17,07 mis

I

Electric attraction

IF elec.attr. 1,46E-09IN/dropl.

Coulomb interaction force

distance between droplets F coulomb

Gravitational force

V d, volume droplet 6,54E-20 m3

m d, mass droplet 6,54E-17 kg

g 9,81 m/s2

F grav . 6,42E-16 N/dropl.

Appendix D. Design electrode

In this appendix information needed for the choice of electrode material and configuration are given. Material properties are given in Appendix D-1, model configurations are given in Appendix D-2 and Electric field contours of different shapes are given in Appendix D-3.

0-1

Resistivity table

For the choice of electrode material for the yew tree milking unit, electrical resistivity of the material is important. The resistivity should be low, since that means that the conductivity is highest and the energy losses are minima I. Copper and silver have the lowest resistivities of all the materials in the list in Table D-1. Although this list is not complete, it gives a brief overview of the possible materiais.

Table 0-1 Electrical resistivities14 and thermal conductivities15 of different materials

Metal Resistivity Thermal conductivity

p(lO-sO m) A/(W m-1 _K-1 ) Aluminium 2.42 236 Antimony 39 25.5 Arsenic 26 Barium 30.2 Beryllium 3.02 218 Bismuth 107 8.2 Cadmium (0.54 K) 6.8 97 Calcium 3.11 Cerium 73 11 Caesium 18.8 36 Chromium 12.7 96.5 Co balt 5.6 105 Copper 1.54 403 Dysprosium 89 10.5 Erbium 81 15 Europium 89 Gadolium 126 10 Gallium (1.1 K) 13.6 41 Gold 2.05 319 Hafnium (0.35 K) 30.4 23 Holmium 90 16 Indium (3.35 K) 8.0 84 Iridium (0.14 K) 4.7 147 Iron 8.57 83.5

14 Jones, R.G., National Physics laboratory, Kaye&Laby, Tables of Physical & Chemical Constants, Section 2.6: Electricity and magnetism, http://www.kayelaby.npl.co.uk/generalphysics/26/261.html. accessed October 28,2008.

15 MorreIl, L., National Physics laboratory, Kaye&Laby, Tables of Physical & Chemical Constants, Section 2.3.7: Thermal Conductivities, http://www.kayelaby.npl.co.uk/generalphysics/26/261.html. accessed October 28,2008.

•

Lanthanum {4.71

Kl

54 13 Lead {7.2

Kl

19.2 36 Lithium 8.53 86 Lutetium 54 17 Magnesium 4.05 157 Manganese 143 8 Molybdenum {O.92

Kl

4.85 139 Neodymium 61 Neptunium

-Nickel 6.16 94 Niobium (9.1

Kl

15.2 53 Osmium {O.65

Kl

8.1 88 Palladium 9.8 72 Platinum 9.81 72

•

Plutonium 146 6 Polonium -40 Potassium 6.49 104 Praseodymium 65 12 Promethium 50 Protactinium {1.4

Kl

17.7 Rhenium {1.7

Kl

17.2 49 Rhodium 4.3 151 Rubidium 11.5 58 Ruthenium {0.49

Kl

7.1 117 Samarium 91.4 13 Scandium 50.5 16 Silver 1.47 428 Sodium 4.33 142 Strontium 12.3 Tantalum {4.48

Kl

12.2 57 Technetium {11.2

Kl

-

51 Terbium 113 10.5 Thallium {2.37

Kl

15 47 Thorium {1.37

Kl

14.7 54

•

Thulium 67 17 Tin {3.69

Kl

11.5 68 Titanium {O.39

Kl

39 22 Tungsten {O.Ol

Kl

4.82 177 Uranium {O.68

Kl

28 27 Vanadium {5.03

Kl

18.1 31 Ytterbium 27.7 Yttrium 55 17 Zinc {O.85

Kl

5.48 117 Zirconium {0.55

Kl

38.8 23

Alloy Resistivity Thermal conductivity p(lO-BO m) A/(W m-1 K-1) Alpax gamma* 3.5 188 Alumel 28.1 30 Brass 6.3 106 Bronze 13.6 53 Chromel P 70.0

--Constantan 49 22 German silver 40 23 Lo-Ex* 3.95 Manganin 41.5 21 Monel 42.9 21 Nichrome 107.3 13 RR 59t 3.5

•

RR 77* 3.95 Steel, Carbon 17.0 ~51 11 18/8 66.3 11 Era ATV 98.0 11 11 Ni-Cr 27.7 13.6 11 Silicon 41.9 11 Stainless 55.0 Pt 90%, Ir 10% 24.8 31 Pt 90%, Rh 10% 18.7 38 Ti 92.5%, AI 5%, Sn 2.5% 155.6 7 Ti 96.0%, AI 2.0%, Mn 2.0% 110.0 9.3 Zr 93.2%, Sn 6.7%, C 0.1% 132.8

-

-Zr 97.6%, Sn 2.3%, C 0.1% 91.5

--Carbon Resistivity Thermal conductivity

p/(Om)

A/(W m -1 K-1₎

•

Amorphous ~ 6 x 10-5 1.5 Graphite 3-60 x 10-6 80-230

Pyrolytic graphite, along planes ~ 5 x 10-6 2130

11 11 normal to planes ~ 5 x 10-3 6.4

Other elements Resistivity

Thermal conductivity

p/(Om)

A/(W m-1 _K-1 ) Germanium 1-500 x 10-3 67 Selenium ~0.1 0.43 (amorphous) Silicon 1-600 x 10-1 168 Tellurium ~ 3 x 10-3 ~ 2.3

•

•

0-2

Model configurations

For different configurations of the electrode the electrie field is assessed using the program Lorentz E. There is a symmetric arrangement of the needies as weil as an asymmetrie arrangement. The coordinates and other input are discussed below.

0-2.0 Symmetrie vs. asymmetrie

The tips of the needies have a z-coordinate of 30 mm, the top surfaces have a z-coordinate of 35 mmo This is so in all cases. The needies are modelled as water and are grounded, hence have a potentialof

°

kV.

For the symmetric case, there are nine needies. One of which is located at x,y = 0,0 mmo Four others have

x

and y coordinates 5 mm from the centre (0,5; 0,-5; 5,0; -5,0). The last four needies are located on the corresponding corners (5,5; -5,5; -5,-5; 5,-5) .

For the asymmetric case, there are 8 needies. Three needies are located at (0,0; 5,0; -5,0). 2 other needies are located at (5,-5; -5,-5) and 3 other needies are located at (5,10; 0,10; -5,10). Hence at 10 mm away from the centre needies.

0-2.b Eleetrodes

The electrode is always modelled with the properties of copper and charged with 4 kV. Plate electrode

The plate electrode is a flat, copper electrode of 2 mm thiek and 60 mm by 60 mm with x,y = 0,0 as centre. It is charged with 4 kV and located with its upper surface at z = 15 mmo

As insulator in one case, a glass layer is put on top of the copper plate. The glass plate is 0.5 mm thick, hence its upper surface is at z = 0.5 mmo

V-shoped eleetrodes

The V-shaped electrodes consist of 2 plates in an angle. The upper corner of the V is located at

x

=

x,

y = 0, z = 15. The upper points of the planes are at y = 30/-30 or at y = 45/-45, z = 30. To make a volume, a thiekness has to be applied; the corners on the lower side of the plane are located at: y = 31/-31 or at y = 46/-46, z = 29. The lower point in the corner is located at y = 0, z = 13.

Wires

The wires modelled in the

x

direction. They are located with their centre at z =

°

for the "wires

-x-"

and with their tops at z = 15 for "wires -x- close". They have a length of 60 mm and the diameter is

1 mm and the spacing between the centres of the wires is 5 mmo All the 13 wires are charged with

4 kV.

Grid

The grid is modelled in the same way as the wires. The wires of this grid are 1 mm in diameter and are located 5 mm from one another. The dimensions of the grid are 60 x 60 mmo At first the grid is place at a top height of 15 mmo

Curved plote

The curved plate is modelled in the x direction as weil. The upper side of the plate has a curve through the points y = 30/-30, z = 30 and y = 0, z= 15. The lower side is the same curve 2 mm down.

0-3

Model results

The different electrode configurations were mode lied with bath a symmetric (I) and asymmetric (r) arrangement of needIes. The results of the modelling in terms of electric field contours are shown in the pictures below for bath situations, for all electrode shapes at a height of 28 mmo

0-3.a Plate

The results of the plate electrode are visible in Figure 0-1(1) and Figure 0-1(r) for bath cases. The maximum field strength visible for the symmetric case is 2.843.105

Vlm

and for the asymmetric case

2.582.105

Vlm

.

Figure 0-1 Results of plate electrode with symmetrie (I) and asymmetrie (r) needie arrangement

0-3.b V-shapes

The results of the V-shaped electrodes are visible in Figure 0-2(1) and Figure 0-2(r) for the sharper angle (126 deg.(l)) and in Figure 0-3(1) and Figure 0-3(r) for the unsharp angle (143 deg.(2)). The maximum field strength visible in case of the sharper angled electrode for the symmetrie case is

3.008.105

Vlm

and for the asymmetric case 2.910.105

Vlm

.

The maximum field strength visible in case of the unsharp angled electrode for the symmetrie case is 2.994.105

Vlm

and for the asymmetrie case 2, 735.105

Vlm.

Figure 0-2 Results of V-shaped electrode with sharper angle for symmetrie (I) and asymmetrie (r) needie arrangement

•

•

•

Figure 0-3 Results of V-shaped electrode with unsharp angle for symmetrie (I) and asymmetrie (r) needie arrangement

0-3.c Curve

The results of the eurved plate electrode are visible in Figure 0-4(1) and Figure 0-4(r) for both cases .

The maximum field strength visible for the symmetrie case is 2.898.105

Vlm

and for the asymmetrie case 2.670.105

Vlm

.

Figure 0-4 Results of eurved plate electrode for symmetrie (I) and asymmetrie (r) needie arrangement

0-3.d Wires

The results of the wires are visible in Figure 0-5(1) and Figure 0-5(r) for both cases. The maximum field strength visible for the symmetrie case is 2.801.105

Vlm

and for the asymmetrie case 2.546.105

Vlm.

D-3.e Grid

The results of the grid electrode are visible in Figure D-6(1) and Figure D-6(r) for both cases. The

maximum field strength visible for the symmetric case is 2.822.105

Vlm

and for the asymmetric case

2.564.105

Vlm

.

Figure 0-6 Results of grid electrode for symmetrie (I) and asymmetrie (r) needie arrangement

•

Appendix E.

Design Insulator: Material Choice

In this appendix different material properties are given for thermoplast polymers, thermoset polymers and several types of glass. These properties are used for the choice of insulator material in the design of the taxane milking device. In Appendix E-1 the electric properties are given, in Appendix E-2 the chemical stabilities are given and in Appendix E-3 the water absorption.

E-l

Electric properties of polymerie and glass materials

In the tables below the electric properties of polymerie thermoplasts (Tabie E-1), thermosets (Tabie E-2) and glass materials (Tabie E-3) are given. All the values that are listed are values that were measured using certain standard measurement methods; the names of these standards can be found

between brackets, e.g. [ASTM 0-150]. The electric properties that are listed are the dielectric

constant, volume resistivity, dielectric strength, and dissipation factor. The dielectrie constant

determines how much of an electric field goes through the material compared to vacuum. The

volume resistivity is the resistance between opposite faces of 1.0 cm3 of the material, the dielectric

strength is the maximum field a material can withstand before a breakdown current goes trough.

These values are the most important ones for the design. Finally, the dissipation factor is a measure for the power losses.

Table E-l Electric properties of thermoplast polymers

Material Oielectric Volume Oielectric Oissipation Source

constant resistivity strength factor

[ASTM- (Ohmecm) (kV/mm) [ASTM

0-150] [ASTM 0-257] [ASTM 0-149] 150]

ABS (acrylonitrile 2.90 1E14 37.5 0.013 [1]

butadiene styrene)-unfilled

Acetal homopolymer 3.70 1E15 19.7 0.005 [1]

Unfilled

Acetal homo impact 3.60 lE15 0.007 [1]

modified

Acetal Homo 20% PTFE 3.10 1E16 0.009 [1]

Acetal copolymer- 3.70 1.30E16 19.7 0.006 [1]

unfilled

Acetal copolymer- 3.90 3.80E15 19.7 0.0062 [1]

25% GR (fibre glass reinforced)

PAN (Polyacrylonitrile) 4.2 0.033 [2], [3]

Polyvinyl acetate 3.5 3.10E9 300

-

[2], [3]

PMMA (Polymethyl 2.76 1.0E14 16.0-20.0 0.04 [2], [3]

methacrylate)

HDPE (high density 2.40 1E15 40.2 0.0003 [1]

polyethylene) Homo -unfilled

Nylon 6 - unfilled 3.60 1E14 0.02 [1]

(HSL)

Nylon 6 - 30% GR 4.30 1E1S 0.019 [1]

Nylon 6/6 - Unfilled 3.60 1E15 0.02 [1]

(HSL)

Nylon 6/6 - 33% GR 3.70 1E15 0.02 [1]

Nylon 6/6 - 40% 3.80 1E15 0.01 [1]

mineral

Nylon 6/12 - 33% GR 3.40 1E15 20.5 0.02 [1]

PAl (Polyamide-imide) 4.60 2E16 23.6 0.044 [1]

-40% GR

Nylon 4/6 - 30% GR 3.70 3E15 25.2 0.023 [1]

PPA (poly-phtalamide) 4.00 1E16 20.0 0.023 [1]

-15% GR

PPA- 33% GR 4.30 2E16 22.0 0.022 [1]

•

PEEK (Polyether- 1E16 50.0 0.003 [1]

etherketone) - unfilled 3.40 PEEK -30% GR 3.61 1E16 19.7 0.004 [1] PC (polycarbonate)- 2.96 1E17 0.01 [1] unfilled PC-30%GR 3.31 1E17 0.007 [1] PBT (polybutylene 3.10 4E16 0.02 [1] terephtalate) - unfilled PBT - 30% GR 3.70 3.4E16 0.02 [1]

PET (Polyethylene 3 lE15 0.012 [1], (2) terephtalate) (Mylar)

PET (polyethylene 3.50 lE15 0.012 (1)

terephtalate) - 30% GR

PET-45%GR 3.90 lE15 0.011 (1)

Lep (Iiquid crystal 3.60 lE16 35.5 0.033 (1)

polymer, e.g. Kevlar)-30%GR

PEl (polyether-imide) - 3.15 lE17 24.0 0.0013 (1)

unfilled PEI-30% GR 3.70 3E16 0.0015 (1) PPD (polyphenylene- 2.59 4.5E16 0.002 [1], (2) oxide) - 30% GR PPS (polyphenylene- 3.80 2.0E15 0.0014 (1) sulfide) 40% GR PPS- 65% 4.30 2.6E15 0.016 (1) Glass/mineral PP (polypropylene) 2.60 1.4E14 34.5 0.001 (1) Homopolymer unfilled

PP copolymer unfilled lE16 33.8

-

(1)

PP- 30% GR 2.60 lE18 0.003 (1)

•

PTFE (Poly-tetrafluoro- 2.00 lE24 to lE26 20.1 0.0002 [1], (4)

ethylene, Teflon) Unfilled

PFA (perfluoro-alkoxy, 2.10 lE16 140.0 0.00009 [1], (3)

Teflon-PFA) - unfilled

PES (polyether- 3.50 lE16 0.005 (1)

sulfone) - 30% GR

PSU (polysulfone) - 3.50 lE16 0.005 (1)

30%

PE (Polyethylene) 2.3 - 17.7-39.4 0.0004- [2], [3] 0.0003 PS (Polystyrene) 2.6 8.4Ell 20.0-28.0 0.00015 [2], [3] (amorph.), 0.0003 (crystalline)

Table E-2 Electric properties of thermoset polymers

Material Oielectric Volume resistivity Oielectric Dissipation Source constant (Ohmecm) [ASTM strength factor

[ASTM-150] 0-257] (kV/mm) [ASTM

0-149] [ASTM

D-150]

Alkyd - glass 3.20 1E14 0.015 [1]

fibre filled

DAP (diallyl 4.40 1E14 0.017 [1]

phtalate) -unfilled

Epoxy - unfilled 4.43 l.2E15 0.034 [1]

PI (polyimide) - 3.55 5.0E14 0.0034 [1] unfilled Polyester - 4.95 1.6E14 0.016 [1] unfilled

•

Silicone - Glass 4.70 0.007 [1] fiber filled

Table E-3 Electric properties of several types of glass

Type Oielectric Volume Dielectric strength Dissipation Source constant resistivity (kV/mm) [ASTM D- factor

[ASTM- (Ohm cm) 149] [ASTM

D-150] [ASTM D-257] 150] Pyrex 7040 4.65 0.0027 [2], [5] Pyrex 7050 4.77 0.0036 [2], [5] Pyrex 7060 4.70 0.0038 [2], [5] Pyrex 7070 4.00 0.0012 [2], [5] Pyrex 7720 4.50 0.0031 [2], [5] Pyrex 7750 4.28 0.0026 [2], [5] Pyrex 7760 4.50 0.0018 [2], [5] Vycor7230 3.83 0.0015 [2], [6] Vycor 7900 3.90 0.00059 [2], [6] Vycor 7910 3.80 0.00024 [2], [6] Vycor 7911 3.80 0.00019 [2], [6]

G.E. Clear 3.81 4.0E9-3.0E10 9.9E-05 [2], [6] (silica glass)

Quartz 3.75 5.3E-05 [2],[5],

(fused) [7], [8]

E-2

Chemical stability of polymers and glass materials

In the following tables the stability of the polymers (Tabie E-4 and Table E-5) and glass materials (Tabie E-6) under operating conditions is given, i.e. stability under ethanol and UV exposure.

For ethanol the letters in the tables mean the following:

U = unacceptable performance; effect of contact varies from: catastrophic failure (dissolution) to severe degradation (cracking)

M

=

marginal performance; only short exposures at low temperatures is allowed and in applications where significant loss of mechanical properties is not critica!.

A

=

acceptable performance; acceptable performance in ordinary exposure. For long term exposure at low temperatures there might be some minor loss of properties.

Ex

=

excellent performance; the polymer is unaffected by the chemical reagent, with respect to time, temperature, and stress applied.

For UV-resistance the letters in the tables mean the following:

U = unacceptable performance; cannot withstand UV-light, polymer bonds will be broken as soon as the material is exposed to it, and the material will get brittie very soon.

M = marginal performance; can only be exposed to small doses of UV-light, otherwise the material will get brittie after a few months. Additives like UV-stabilisers or UV-absorbers are necessary. A

=

acceptable performance; will not degrade under UV-light, only af ter a long period of constant exposure. Use of UV-stabilising additives recommended.

Ex

=

excellent performance; high to very high stability under UV-light. No UV-stabilising additives are necessary.

The stabilities th at are too low for the application as insulator of a taxane milking device are marked with red in the tables.

Table E-4 Ethanol resistance and UV resistance of thermoplast polymers Material

Ethanol resistanee UV resistanee

[Immersion, ASTM 0543] [ASTM 0-1435] Sou ree

ABS (acrylonitrile butadiene

[9]

styrene) - unfilled M-A

Acetal homopolymer Unfilled A M-A

[9]

Acetal homo impact modified A M-A

[9]

Acetal Homo 20% PTFE A M-A

[9]

Acetal copolymer -unfilled A M-A

[9]

Acetal copolymer - 25% GR (fibre

[9]

glass reinforced)

A M-A

Acrylic - heat resistant A

[9]

PAN (Polyacrylonitrile) (9)

Polyvinyl acetate (3), (10)

PMMA (Polymethyl methacrylate) (3), (11)

HOPE (high density polyethylene) (9)

Homo - unfilled

Nylon 6 - unfilled (HSL) A M-A (9)

Nylon 6 - 30% GR A M-A (9)

Nylon 6/6 - Unfilled (HSL) A M-A (9)

Nylon 6/6 - 33% GR A M-A (9)

Nylon 6/6 - 40% mineral A M-A (9)

Nylon 6/12 - 33% GR A M-A (9) PAl (Polyamide-imide) - 40% GR (12), A M (13) Nylon 4/6 - 30% GR A M-A (9) PPA (poly-phtalamide) - 15% GR A A (3) PPA-33% GR A A (3) PEEK (Polyether-etherketone) - (14) unfilled Ex A PEEK - 30% GR Ex A (14)

•

PC (polycarbonate)- unfilled A A (9) PC-30% GR A A (9)

paT (polybutylene terephtalate) - A-Ex M-A (3)

unfilled

PET (Polyethylene terephtalate) (9)

(Mylar) Ex A

PET (polyethylene terephtalate) - (9)

30%GR Ex A

Lep (Iiquid crystal polymer)- 30% [15],

GR Ex [16]

PEl (polyether-imide) - unfi"ed [13],

A A [17] PEI-30% GR [13], A A [17] PPD (polyphenylene-oxide) - 30% [9] GR Ex Ex PPS (polyphenylene-sulfide) 40% [9] GR Ex A PPS - 65% Glassjmineral Ex A [9] PP (polypropylene) Homopolymer [9] unfi"ed A PP copolymer unfi"ed A [9] PP- 30% GR A [9] PTFE (Poly-tetrafluoro-ethylene, [9] Teflon) Unfi"ed Ex Ex

PFA (perfluoro-alkoxy, Teflon- [9]

PFA) - unfi"ed Ex Ex PES (polyether-sulfone) - 30% GR Ex M [18] PSU (polysulfone) - 30% [9] Polysulfones [9]

•

PE (Polyethylene) [9] PS (Polystyrene) [9]

Table E-S Ethanol resistance and UV resistance of thermoset polymers

Material Ethanol resistance [Immersion, UV resistance [ASTM Souree ASTM 0543] 0-1435]

Alkyd - glass fibre filled DAP (diallyl phtalate) -unfilled

Epoxy -unfilled Ex A (9) PI (polyimide)- unfilled Ex Ex (9) Polyester - unfilled A A (9) Silicone - Glass fiber (9) filled A Ex

Table E-6 Ethanol resistance and UV resistance of several types of glass

Material Ethanol resistance [Immersion, UV resistance [ASTM Source ASTM 0543] 0-1435] Pyrex 7040 Ex

-

(20) Pyrex 7050 Ex

-

(20) Pyrex 7060 Ex

-

(20) Pyrex 7070 Ex

-

(20) Pyrex 7720 Ex

-

[20) Pyrex 7750 Ex

-

(20)

•

Pyrex 7760 Ex - (20) Vycor7230 Ex

-

(20) Vycor7900 Ex

-

(20) Vycor 7910 Ex

-

(20) Vycor 7911 Ex

-

(20) G.E. Clear (silica glass) Ex

-

(20) Quartz (fused) Ex transparent to UV [20],

E-3

Water absorption of polymers

In the tables below the water absorption of polymers (Tabie E-7 and Table E-8) is given. The water

absorption numbers th at are unacceptable are marked with red, namely a 24 hour water absorption

above 0.30% and a water saturation absorption above 1.0%.

Table E-7 Water absorption and hardness of thermoplast polymers

Material

ABS (acrylonitrile butadiene styrene)-unfilled

Acetal homopolymer Unfilled Acetal homo impact modified Acetal Homo 20% PTFE Acetal copolymer - unfilled

Acetal copolymer - 25% GR (fibre glass reinforeed)

Acrylic - heat resistant PAN (Polyacrylonitrile) Polyvinyl acetate

PMMA (Polymethyl methacrylate)

HDPE (high density polyethylene) Homo -unfilled Nylon 6 - unfilled (HSL) Nylon 6 - 30% GR Nylon 6/6 - Unfilled (HSL) Nylon 6/6 - 33% GR 24 hr water absorption (%) [ASTM 0-570] 0.20-0.45 0.25 0.25 0.20 0.22 0.29 0.20-0.30

Water absorption Souree saturation (%) [ASTM 0-570] - [21] 0.90 [21] 0.90 [21] 0.72 [21] 0.80 [21]

-

[21] - [21] [21], [3] [211, [3] [21], [3] [21] [21] [21] [21]

•

Nylon 6/6 - 40% mineral Nylon 6/12 - 33% GR 0.16 [21] PAl (Polyamide-imide) - 40% GR [21] Nylon 4/6 - 30% GR 0.26 [21], [3] PPA (poly-phtalamide) -15% GR 0.30 [21], [3] PPA-33% GR 0.21 [21]

PEEK (Polyether-etherketone) - unfilled 0.14 0.50 [21],

[13]

PEEK - 30% GR 0.08 0.12 [21],

[13]

PC (polycarbonate)- unfilled 0.15 0.58 [21]

PC-30% GR 0.14 0.26 [21]

PBT (polybutylene terephtalate) - unfilled 0.08

-

[21]

PBT-30% GR 0.06

-

[21]

PET (polyethylene terephtalate) (Mylar) 0.05

-

[21]

PET (polyethylene terephtalate) - 30% GR 0.05

-

[21]

PET-45% GR 0.04

-

[21]

LCP (Iiquid crystal polymer)- 30% GR 0.04 0.30 [21]

PEl (polyether-imide) - unfilled 0.25 [21]

PEI-30% GR 0.16 0.90 [21] PPO (polyphenylene-oxide) - 30% GR 0.06

-

[21] PPS (polyphenylene-sulfide) 40% GR 0.004-0.08 0.08 [21], [3] PPS - 65% Glass/mineral 0.02-0.07 0.07 [21], [3]

PP copolymer unfilled 0.03

-

[21]

PP-30%GR 0.01-0.05 - [21]

PTFE (Poly-tetrafluoro-ethylene, Teflon) <0.01

-

[21]

Unfilled

PFA (perfluoro-alkoxy, Teflon-PFA) - <0.01

-

[21]

unfilled PES (polyether-sulfone) - 30% GR 0.12-0.17 [21] PSU (polysulfone) - 30% 0.30 0.50-0.60 [21] Polysulfones 0.30 0.70 [21] PE (Polyethylene) <0.01 0.01 [21],

-[3] PS (Polystyrene) 0.01-0.03 0.01-0.03 [21]

Table E-8 Water absorption and hardness of thermoset polymers

Material 24 hr water Water absorption Sou ree

absorption (%) saturation (%) [ASTM 0-570] [ASTM 0-570]

Alkyd - glass fibre filled 0.050-0.240 - [21]

DAP (diallyl phtalate) - unfilled 0.25

-

[22]

Epoxy -unfilled 0.079-0.300 - [21]

PI (polyimide)- unfilled 0.24 [21]

Polyester - unfilled 0.170-0.220

-

[21]

e

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retrieved via www.knovel.com. accessed October 26, 2008.

(21) Campo, E.A., Selection of polymerie materials - how to select design properties from different

standards, 2008, William Andrew Publishing, Chapter 5: Physical properties of Polymerie

Materiais, retrieved via www.knovel.com. accessed October 28, 2008.

(22) Plasmetex industries, plastie parts manufacturer for the electronies industry, information on

Appendix F.

Total Design

In this appendix some parameters needed for the total design of the taxanes milking device are investigated. In Appendix F-1 the electrode spacing and the number of electrodes is established, in

Appendix F-2 the surface modification is applied.

F-l

Electrode Spacing and number of electrodes

For different layers of electrodes, the optimum ranges of distance and corresponding number of electrodes are determined. The distance between the electrodes is not only dependent on the electric field interference. The number of branches reached and the material costs are accounted for as weil. The optimum will most likely lie between 5 and 10 cm spacing. The lower limit results from the facts that the electrode and insulator have a certain thickness and the branches must be able to fit in between. Beside this, the electric field must not be altered too much from the normal situation with only one electrode, to keep a controlIabie situation. The upper limit results from the fact that leaving too much space in between, too little branches will be reached in the process, leading to an inefficient operation, hence reduction of profit.

In order to see the effect of an extra plate, the electric field beneath and above the needies is investigated in three cases; only a single electrode (see Figure F-1(1)), for comparison, a second electrode at 5 cm above the first and a second electrode at 10 cm from the first. For the latter two cases the electric field is modelled with a grounded aluminium plate in between (see Figure F-1(r)) and without one, the aluminium plate being there for shielding the field. The field around the needies is not included, 50 the field gradient can be more exactly examined.

Figure F-l Electric field around the needies with single electrode (I) and with double electrodes with grounded aluminium in between (r)

A summary of the electric field strengths around the needies is given in Figure F-2. The resulting electric field strength just below the needies in case of double electrodes should be approximately equal to that of the single electrode configuration.

2.8 2,78

V6

2.74 2,72 2.7 2,G8 2,66 2,64 without alumlnum with alumlnum single electrode .~cm . 10r.m

Figure F-2 Electric field strength around the needies for th ree cases; double plates with aluminium in between, double plates without aluminium in between at 5 and 10 cm, and a single plate

From Figure F-2 it can be seen that the electric field increases drastically around the needies when an extra plate is introduced at 5 cm from the first one. Even with a grounded aluminium plate, the variation in the field is too large. When this plate is moved to a distance of 10 cm, it can be seen that the field without the aluminium plate is still too large, however, when a grounded aluminium plate is introduced, the field comes just enough in the range of the single electrode to be applied. It is visible that a grounded aluminium plate can shield the field a little, however, wh en an insulator is inserted between the plates, preferably one located right underneath the electrode, the field will be shielded even more, allowing for a smaller distance between the different electrodes.

The number of electrodes on the apparatus is dependent on the spacing of the plates and the height of the total configuration. The height of the total configuration is dependent on the height of the trees that will be subjected to the spray. For trees of 1.4 meters high the number of electrodes will be between 13 and 27, the number of electrodes being calculated as:

No

=

~

eiBht

of

apparatus )

-1

.1

acing

of electrodes

When the range is narrowed down to a number, the exact number of electrodes can be determined.

F-2Modification of insulator surface

The wettability of the insulator, PAl, has to be increased in order to gives the sap that leave the needie an affinity for the insulator surface. The contact angle of the PAl layer with the sap has to be decreased from 87" to less than 80·. This can be done by UV/ozone treatment. Oxygen present in the air forms ozone in presence of high-energy UV radiation. In turn, when the ozone falls apart in oxygen and an oxygen radical, the latter can cause oxidation at active surfaces. The wettability and the adhesion can hereby be improved16 • It was found that this application can be applied at a variety

16 Bhurke, A.S., Drzal, L.T., Surface treatment

~f

palymers and composites with UV light in air to improve

of polymers, like thermoplastics, thermosets, and rubbers16

,17, No literature source about the

modification of PAl was found, however since it is already been successful at many thermoplastics it is assumed that will also work for PAL

Below, achart (see Figure F-3) is presented where the change in contact angles is shown for different

surfaces, The red arrows point towards thermoplastics, It shows that the contact angles for

polypropylene decreases from 96° to 81°, for polycarbonate from 78° to 26° and for polymethyl methacrylate from 66° to 26°, The contact angle decrease can be controlled by the UV wavelength and irradiation, ozone concentration, and the temperature, Also, the surface treatment takes place in a short time (30-120 seconds) and it low-cost.

Wettability and Adhesive Bond Improvements tor

Polymers caused by UV Treatment

1.00_---.,.

u.

_..

contact AngII . 1.10 1.40 0.20 ElI - . .

.

uv_

~o 4CCO uco

-

!

i

uco c: !

'"

S 1.00 ... _"J!IL.,IIIa.lr-... 2CCO Co

,.

"

.. .20

..

,4CO !

...

c

..

.

..

".10 ,eoo ".10 teO .1.10 . . . L..II _ _ _ L..

ItTPO M'TPO PP '11:'1 111::1 I'C "ni ,.12 NT IIIC "" !LUI - . . \tE

t

t

t

Figure F-3 Change in contact angle when different polymer surfaces are treated with UV (red arrows point toward thermoplastics). Polypropylene (PP), Polycarbonate (PC), Polymethyl methacrylate (PMMA)

17 Kumagai, H., et al., (2007), Surface Modification of Polymers by ThermaIOzone Treatments, AZojomo; Journal of Materials Online, Volume 3, December 2007.

Appendix G. Economics: Assumptions and Calculations

In th is appendix extended economical calculations and assumptions are presented for the taxanes

milking device. In Appendix G-1, reasons for the choice of yew species are shown, in Appendix G-2 the assumptions for the plantation model are given,

G-l

Choice of yew species

An estimate for the prices of the three main taxa nes was needed in order to chose which yew species to use for the plantation.

Table G-l Prices of the th ree main taxanes18

grams Iprice price/g Ipurity

11paclitaxel 0,5 550 1100 98.0%

4 baccatin 111 0,5 390 780 98.0%

510-deacetyl baccatin 111 0,5 750 1500 98.0%

Prices are based on 0.5 gram prices that were published by the company 38 Scientific Corporation on Scifinder. It is assumed that the price drop that would occur when larger amounts are sold is about the same percentage for all three compounds, however the prices can be compared relatively. Table G-2 Yield of different taxanes in different yew species where 1 is paclitaxel, 2 is lO-deacetyl paclitaxel,

3 is cephalomannine, 4 is baccatin 111, and 5 is lO-DAB

In ~g/g dried needies

1 2 3 4 5 6 total

Taxus Baccata European vew 41 198 22 14 762 3 1,20

Taxus Baccata cv. 63 179 42 10 468 6 0,78

Taxus Brevifolia Pacific vew 130 0 0 296 41 9132 0,44

Taxus Canadensis Canadian_vew 285 253 289 224 2665 77 4,49

Taxus Celebia Chinese vew 26 81 0 0 70 46 0,13

Taxus CusfJidata Japanese vew 105 113 40 15 120 6 0,31

Taxus cusDidata cv. 136 198 93 18 116 1 0,34

Taxus Floridana Florida vew 516 515 0 0 1689 0 3,10

Taxus Globosa Mexican vew 433 229 480 168 1395 0 2,70

Taxus x hunnewelliana 41 100 0 0 63 0 0,14

Taxus X Media cv. Baccata x CusfJidata 211 205 131 36 230 0 0,61

Taxus Wallichiana Himalavan vew 272 420 0 0 1092 0 1,94

The total relative price of the needies from different species is calculated. This is done by summing up the three most important taxanes, number 1, 4, and 5, when they are multiplied with their

relatively market value.

G-2

Assumptions of plantation model

For the modelling of the plantation several assumptions had to be made. Below, the reasoning

behind the assumptions listed in the report can be found.

The heights of the trees that are planted are assumed to be 0.5 m. When looking at the prices of tree of different height, a large increase in price is seen between trees of 0.4-0.6 mand trees of 0.6-0.8 m

(see Figure G-l) due to the fact that larger trees have to have a bali of earth around the roots when

sold. It was decide to piek trees from 0.4-0.6m (ave rage O.5m) to stay in the lower price region.

Prices of tree vs. height

18 I/) 0 16

...

•

::l 14 CP

•

I: ₁₂

•

CP 10 CP

...

₈

-

...

CP ₆

c..

•

•

CP 4 CJ

...

';: 2 Q. 0

o

20 40 60 80 100 120

Height in cm

Figure G-l Relationship between the prices of trees versus the height. Information is based on prices from Directpla nt.com 19

To make a dense hedge, it is necessary to plant three to four trees per meter20• In other words, the

spacing between the trees is 0.25 m.

The width of the hedges is fixed at 0.8 m. This width is reasonable for a full-grown tree21• Over the

year, even when a tree is cut annually, the tree expands in the width. When the tree's width is too large, it can be cut smaller, however th en there will be a year you are not able to milk the tree.

It was found that the annual growth rate of the Taxus Canadensis is less than 12 inches (0.30 m)22.

Since the maximum growth rate will most likely not be achieved, the growth rate used for the calculations was set at 0.2 m/yr.

19 Directplant (2008), Directplant.cam de grootste on-fine plantenshop,

http://www.directplant.nl/php/artikel details.php?aid=862&cid=393&method. accessed October 12,2008.

20 P. v. Gorp, Boomkwekerij, Taxus coniferen haaglanden, Tips & Advies, http://www. kwekerij-coniferen. nI/tips advies.html. accessed October 13, 2008.

21 Mauritz, H., director Combination Mauritz Boomkwekerijen, Personal communication, October 1, 2008. 22 Michigan State University Extension (1999). Taxus Canadensis -- Canadian Yew,