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"Jochen Kieninger
\n",
"**Electrochemical Methods for the Micro- and Nanoscale**
\n",
"www.electrochemical-methods.org\n",
"\n",
"## Task 6.1 (Rotating ring disk electrode - collection efficiency)\n",
"\n",
"The collection efficiency of an RRDE depends on geometrical parameters only, assuming stable reaction products. The radii are $r_1$ for the disk, $r_2$ the inner and $r_3$ the outer of the ring."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "moved-library",
"metadata": {},
"outputs": [],
"source": [
"import numpy as np"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "characteristic-registration",
"metadata": {},
"outputs": [],
"source": [
"r1 = 2.5 # mm (disk radius)\n",
"r2 = 3 # mm (inner ring radius)\n",
"r3 = 4 # mm (outer ring radius)"
]
},
{
"cell_type": "markdown",
"id": "hybrid-privilege",
"metadata": {},
"source": [
"- For the collection efficiency $N$, Albery and Bruckenstein (https://dx.doi.org/10.1039/tf9666201920) proposed a generally accepted solution:"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "surgical-little",
"metadata": {},
"outputs": [],
"source": [
"a = (r2/r1)**3 -1\n",
"b = (r3/r1)**3 - (r2/r1)**3"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "portuguese-sixth",
"metadata": {},
"outputs": [],
"source": [
"def FF(x):\n",
" result = np.sqrt(3)/4/np.pi\n",
" result *= np.log((1+x**(1/3))**3/(1+x))\n",
" result += 3/2/np.pi*np.arctan((2*x**(1/3)-1)/np.sqrt(3))\n",
" result += 0.25\n",
" return result"
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "endangered-silence",
"metadata": {},
"outputs": [
{
"data": {
"text/plain": [
"0.4"
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"N = 1-FF(a/b) + b**(2/3)*(1-FF(a))\n",
"N = N - (1+a+b)**(2/3)*(1-FF(a/b*(1+a+b)))\n",
"round(N, 2)"
]
}
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