- Design goals
- Features
- Installation
- Getting started
- Making Isotopes
- Making Elements
- Making Compounds
- Making Materials
- Making Homogenised_mixtures
- Making material cards
- Changing the nuclear library
- Examples
- Todo
The material composition impacts the transport of neutrons and photons through the material. Neutronics codes attempt to simulate the transport of particles through matter and therefore require the material composition. This software aims to ease the creation of customisable materials for use in neutronics codes. The motivation behind this software was the desire to create materials once and reuse them in a in a variety of neutronics codes and engineering software. Materials are constructed from properties such as temperatures, pressures, isotope enrichment which can be adjusted by the user.
- Generate isotopes, elements, materials, chemical compounds and homogenised mixtures.
- Create your own custom materials and chemical compounds or select from the internal database.
- Optional parameters for your creations include:
- specified densities (g/cm3 or atoms per barn cm)
- homogenisation fraction (volume or mass)
- void fraction
- elements present (atom fraction or mass fraction)
- options for enriched isotopes
- isotopes present (atom fraction or mass fraction)
- temperature (in Kelvin)
- pressure (in Pa)
- Retrieve the properties from your crations, available properties include:
- material cards for Serpent, MCNP and Fispact
- density (g/cm3 or atoms per barn cm)
- zaids
- isotopes present and their mass / atom fractions
- elements present and their mass / atom fractions
- preferential ACE file or nuclear data library
Neutronics material maker is available here on the git repository or via the python package index.
- Install the latest package by cloning this git repository and install locally.
git clone https://github.com/ukaea/neutronics_material_maker.git
cd neutronics_material_maker
python setup.py install --user
pip install -r requirements.txt --user
Should you wish you can also run the test suite. To do this you will need pytest installed.
pip install pytest
python setup.py testThe software can be used to create: Isotopes, Elements, Compounds, Materials or Homogenised_mixture. Properties such as density or material card can be accessed after creation. For example see the eamples.py file in the git repository or continue with this readme.
After installation try importing the package:
from neutronics_material_maker.nmm import *Isotopes form the basic building blocks of more complex objects (Element). An Isotope can be created in 3 different ways. Either specify the symbol and the nucleon number or specify the proton number and the nucleons number or specify the zaid number. Each of these options can be specified as keyword arguments or arguments.
example_isotope = Isotope('Li',7)
example_isotope = Isotope(symbol='Li',nucleons=7)
example_isotope = Isotope(3,7)
example_isotope = Isotope(protons=3,nucleons=7)
example_isotope = Isotope('3006')
example_isotope = Isotope(zaid='3006')Once an isotope is created its properties can be queried.
example_isotope.symbol
>>> Li
example_isotope.nucleons
>>> 7
example_isotope.protons
>>> 3
example_isotope.neutrons
>>> 4
example_isotope.natural_abundance
>>> 0.926
example_isotope.mass_amu
>>> 7.0160034366It is also possible to overwrite the natural abundance of an isotope upon creation. This comes in useful when creating enriched Compounds or Materials which is demonstrated later.
example_natural_isotope = Isotope('Li',7)
example_natural_isotope.abundance
>>> 0.9241
example_enriched_isotope = Isotope('Li',7,abundance=0.5)
example_enriched_isotope.abundance
>>> 0.5Elements form other building blocks of more complex objects (Compounds and Materials). Elements can be created by specifying the symbol and optional enrichment. A simple element construct can be achieved using the element symbol or the proton number or the zaid. The class accepts keyword arguments or arguments.
example_element = Element('Li')
example_element = Element(symbol='Li')
example_element = Element(3)
example_element = Element(protons=3)
example_element = Element('3006')
example_element = Element(zaid='3006')
The natural abundance of an Element is known and the Isotope objects are created accordingly.
If an Element with non natural abundances is required then the isotopes and their abundances can be specified using the enriched_isotopes keyword, as demonstrated in the example below.
example_element = Element('Li',
enriched_isotopes=[Isotope('Li', 7, abundance=0.4),
Isotope('Li', 6, abundance=0.6)])
Once the elements are maded then elemental properties can then be queried. In some cases lists of Isotope objects are returned.
example_element.molar_mass_g_per_mol
>>> 6.94003660292
example_element.protons
>>> 3
example_element.isotopes
>>> [<__main__.Isotope object at 0x7f23ba50bfd0>, <__main__.Isotope object at 0x7f23ba50bed0>]
example_element.element_name
>>> Lithium
example_element.name
>>> Li_6Elements can also be created with enriched Isotope abundances.
example_element = Element('Li',enriched_isotopes=(Isotope('Li', 6, abundance=0.9), Isotope('Li', 7, abundance=0.1)))Chemical equations are referred to as a Compound by the software. Compounds can be any valid chemical formula such as H2O, CO2 or C8H10N4O2.
Compounds can be created using the following command, when both the compound chemical formula and the density in grams per cm3 are specified. If the chemical_equation keyword is not provided then the chemical_equation is assummed to be the first non keyword arguement.
example_compound = Compound('C12H22O11',density_g_per_cm3=1.59)
example_compound = Compound(chemical_equation='C12H22O11',density_g_per_cm3=1.59)mat_Li4SiO4 = Compound('Li4SiO4', volume_of_unit_cell_cm3=1.1543e-21, atoms_per_unit_cell=14, packing_fraction=0.6, enriched_isotopes=[Isotope('Li',7,abundance=0.6),Isotope('Li',6,abundance=0.4)])
Several fusion relevant compounds along with their crystalline volume can be found in the eamples.py file. Compounds included are: Li4SiO4, Li2SiO3, Li2ZrO3, Li2TiO3, Be, Ba5Pb3, Nd5Pb4, Zr5Pb3, Zr5Pb4, Pb84.2Li15.8.
mat_Li4SiO4 = Compound(chemical_equation = 'Li4SiO4',
volume_of_unit_cell_cm3 = 1.1543e-21,
atoms_per_unit_cell = 14)
mat_Li4SiO4.density_g_per_cm3
>>> 2.4136389927905504A Compound can also be enriched much like isotopes can. To enrich an compound the user must pass the desired abundances for the required isotopes in the element. Here is an example for enriched Li4SiO4 with Li6 abundance set to 0.6 and Li7 abundance set to 0.4. You can see that Isotope objects are used for this procedure.
mat_Li4SiO4_enriched = Compound(chemical_equation = 'Li4SiO4',
volume_of_unit_cell_cm3=1.1543e-21,
atoms_per_unit_cell=14,
enriched_isotopes=[Isotope('Li',7,abundance=0.4),
Isotope('Li',6,abundance=0.6)])
mat_Li4SiO4_enriched.density_g_per_cm3
>>> 2.3713790240133186 Other input options for creating a Compound include setting a packing_fraction . The density of the resulting Compound is multiplied by the input packing fraction. This property is included to allow pebble beds.
solid_ceramic = Compound('Be12Ti',
volume_of_unit_cell_cm3= 0.22724e-21,
atoms_per_unit_cell=2)
pebble_bed_ceramic = Compound('Be12Ti',
volume_of_unit_cell_cm3= 0.22724e-21,
atoms_per_unit_cell=2,
packing_fraction=0.64)The density of the Compounds can be found with the density_g_per_cm3 property. Here we can see that the density of the pebble bed is lower than the solid ceramic.
solid_ceramic.density_g_per_cm3
>>>2.2801067618505506
pebble_bed_ceramic.density_g_per_cm3
>>>1.4592683275843523Other input options for Compounds include pressure_Pa and temperature_K which are used when calculating the density of ideal gases and non solids. To make use of this feature the thermo package must be installed.
pip install thermo --userThe density of non solids and gases accounting for thermal expansion can then be found. To use the ideal gas equations the state_of_matter must be specified as 'gas'.
He_compound = Compound('He',
pressure_Pa = 8.0E6,
temperature_K = 823.0,
state_of_matter='gas')
He_compound.density_g_per_cm3
>>> 0.004682671945463105Other coolants can also accept different pressure_Pa and temperature_K values and the density changes accordingly. The state_of_matter must also be specified as 'non_solid'. This example shows the resulting change in density for water at different temperatures and pressures.
water_compound = Compound('H2O',
pressure_Pa = 3100000,
temperature_K = 473.15,
state_of_matter='non_solid')
water_compound.density_g_per_cm3
>>> 0.8664202359381719
water_compound = Compound('H2O',
pressure_Pa = 101325,
temperature_K = 293,
state_of_matter='non_solid')
water_compound.density_g_per_cm3
>>> 0.9990449108576049Once a Compound has been created various properties can be extracted including material cards suitable for use in Serpent (default) simulations with the material_card(code='serpent') and MCNP material_card(code='mcnp') method.
example_compound = Compound('Li4SiO4',enriched_isotopes=(Isotope('Li', 6, 0.9), Isotope('Li', 7, 0.1)))
example_compound.enriched_isotopes
>>> <__main__.Isotope object at 0x7f859e27dfd0>, <__main__.Isotope object at 0x7f859e28d2d0>
example_compound.density_g_per_cm3
>>> 2.4132772544935666
example_compound.description
>>> Li4SiO4__Li6_0.9_Li7_0.1
example_compound.isotopes_atom_fractions
>>> [0.39999999999999997, 0.044444444444444446, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]
example_compound.volume_m3
>>> 8.245e-29
example_compound.molar_mass
>>> 116.526000953
example_compound.elements
>>> [<__main__.Element object at 0x7fea0f159350>, <__main__.Element object at 0x7fea0f159290>, <__main__.Element object at 0x7fea0f1590d0>]
example_compound.material_card(code='serpent')
>>> mat Li4SiO4__Li6_0.9_Li7_0.1 -2.34719115762
>>> 3006.31c 0.4
>>> 3007.31c 0.0444444444444
>>> 14028.31c 0.10247
>>> 14029.31c 0.00520555555556
>>> 14030.31c 0.00343555555556
>>> 8016.31c 0.443364444444
>>> 8017.31c 0.000168888888889
>>> 8018.31c 0.000911111111111One novel feature of the software is the variations of the density of Compounds with isotope enrichment, the density and atom fractions are based on the actual isotopes present within the cryslaine latic. Creating different Compounds for use in parameter studies is easy with a for loop. Here the enrichment of Li6 is changed from 0.25 to 0.5, 0.75 then 1.0 and the calculated density of the resulting Li4SiO4 and normalised atom fractions are printed out each iteration of the loop. The density decreases slowly as Li7 atoms are replaced with Li6. The material_card(code='serpent') also changes accordingly. These density and atom fractions can then be input into other Material makers for codes such as OpenMC or Pyne.
for enrichment in [0, 0.25, 0.5, 0.75, 1.0]:
example_compound = Compound('Li4SiO4',enriched_isotopes=(Isotope('Li', 6, abundance=enrichment), Isotope('Li', 7, abundance=1.0-enrichment)))
print('Li6 enrichment=',enrichment)
example_compound.density_g_per_cm3
example_compound.isotopes_atom_fractions
>>> Li6 enrichment= 0
>>> 2.419758869855734
>>> [0.0, 0.4444444444444444, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]
>>> Li6 enrichment= 0.25
>>> 2.399601172012573
>>> [0.1111111111111111, 0.3333333333333333, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]
>>> Li6 enrichment= 0.5
>>> 2.379443474169413
>>> [0.2222222222222222, 0.2222222222222222, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]
>>> Li6 enrichment= 0.75
>>> 2.359285776326253
>>> [0.3333333333333333, 0.1111111111111111, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]
>>> Li6 enrichment= 1.0
>>> 2.3391280784830926
>>> [0.4444444444444444, 0.0, 0.10246999999999999, 0.005205555555555555, 0.0034355555555555554, 0.4433644444444444, 0.00016888888888888889, 0.0009111111111111111]The above feature is the main motivation behind the software as it allows the user to perform massive parameter studies on various candidate neutron multiplier materials and lithium ceramics for use in fusion breeder blankets.
A custom Material can be constructed by specifiying the density and the isotopes or elemental composition.
One or more element can be specified with the element keyword along with the element_atom_fraction or element_mass_fraction.
Alternativly one or more isotopes can be specified using the isotopes keyword along with the isotope_atom_fractions or isotopes_mass_fractions that make up the material.
The density can be specified as density_g_per_cm3 or atom_density_per_barn_per_cm.
The following example makes a material called Steel which is 95% weight Iron and 5% weight Carbon, with a density of 7.8g per cm3.
mat_Steel= Material(material_card_name='Steel',
density_g_per_cm3=7.93,
density_atoms_per_barn_per_cm=8.58294E-02,
elements=[Element('Fe'),
Element('C')],
element_mass_fractions=[0.95,
0.05])The following two examples show how to construct materials using Isotopes along with either Isotpe_mass_fraction or Isotope_atom_fraction.
mat_using_isotope_mass_fractions = Material(material_card_name='enriched_lithum',
density_g_per_cm3=2.0,
isotopes=[Isotope('Li',7),
Isotope('Li',6)],
isotope_atom_fractions=[0.5,
0.5],
)
mat_using_isotope_atom_fractions = Material(material_card_name='enriched_lithum',
density_g_per_cm3=2.0,
isotopes=[Isotope('Li',7),
Isotope('Li',6)],
isotope_mass_fractions=[0.5,
0.5],
)The software has a some example Materials in the eamples.py file. The elemental composition and densities of Bronze, Eurofer, SS-316LN-IG, DT-plasma, CuCrZr, Glass-fibre, Epoxy, Glass-fibre and Tungten are included. Here is an example of 50:50 DT-plasma constructed using enriched elements.
example_mat1 = Material(material_card_name='DT-plasma',
density_atoms_per_barn_per_cm=1e20,
elements=[Element(symbol='H',
enriched_isotopes=[Isotope('H',2,abundance=0.5),
Isotope('H',3,abundance=0.5)])
],
element_mass_fractions=[1.0]
)
example_mat1.material_card(code='serpent')
>>> mat DT_plasma 1e-20
>>> 1002.31c 0.5
>>> 1003.31c 0.5The other materials available are considerably more detailed in their isotope description. To keep this user manual concise only Glass-fibre and DT_plasma have been demonstrated. One difference between Materials is the known density, the software has materials with density in atom_density_per_barn_per_cm which is useful for Materials such as DT-plasma or density_g_per_cm3 which is useful for Materials such as Glass-fibre. Neutronics codes such as Serpent can accept both options so this is not a problem (density in g/cm3 has a - flag to indicate the units).
mat_Glass_fibre = Material(material_card_name='Glass-fibre',
density_g_per_cm3=2.49,
elements=[Element('H'),
Element('O'),
Element(12),
Element(13),
Element(14)
],
element_mass_fractions=[0.0000383948,
0.6328110447,
0.0499936947,
0.1026861642,
0.2144707015
])
example_mat2.density_g_per_cm3
>>> 2.49
example_mat2.material_card(code='serpent')
>>> mat Glass-fibre -2.49
>>> 1001.31c 3.8390384598e-05
>>> 1002.31c 4.415402e-09
>>> 8016.31c 0.631273313861
>>> 8017.31c 0.000240468196986
>>> 8018.31c 0.00129726264164
>>> 12024.31c 0.0394900194435
>>> 12025.31c 0.00499936947
>>> 12026.31c 0.00550430578647
>>> 13027.31c 0.1026861642
>>> 14028.31c 0.197791315044
>>> 14029.31c 0.0100479523653
>>> 14030.31c 0.00663143409038Materials and Compounds can be combined to form a Homogenised_mixture. Any number of Materials and Compounds can be combined but they must combine to give a volume fraction of 1.0. Here are some examples:
mat_bronze = Material(material_card_name='Bronze',
density_g_per_cm3=8.8775,
elements=[Element('Cu'),
Element('Sn') ],
element_mass_fractions=[0.95,
0.05 ])
mat_bronze.density_g_per_cm3
>>> 8.8775
mat_water = Compound('H2O',density_g_per_cm3=0.926)
mat_water.density_g_per_cm3
>>> 0.926
mat_CuCrZr = Compound('CuCrZr',density_g_per_cm3=8.814)
mat_CuCrZr.density_g_per_cm3
>>> 8.814The two Compounds and 1 Material can then be mixed with volume_fraction the following way. This Homogenised_mixture contains 20% volume Water, 30% volume CuCrZr and 50% Bronze.
mat_mix = Homogenised_mixture(mixtures=[mat_water,
mat_CuCrZr,
mat_bronze],
volume_fractions=[0.20
0.30
0.5])
mat_mix.density_g_per_cm3
>>> 7.26815The resulting material card comprises of the combined three material cards with modified atom fractions to account for the volume fraction of each component. The material name is also based on the combination of the three components along with their volume_fractions.
mat_mix.material_card(code='serpent')
>>> mat H2O_vf_0.2_CuCrZr_vf_0.3_Bronze_vf_0.5 -7.26815
>>> %
>>> % H2O with a density of 0.926gcm-3
>>> % volume fraction of 0.2
>>> % mass fraction of 0.0254810371277
>>> 1001.31c 0.161622473319
>>> 1002.31c 1.85887221347e-05
>>> 8016.31c 0.0806241371301
>>> 8017.31c 3.07118017878e-05
>>> 8018.31c 0.000165682088592
>>> %
>>> % CuCrZr with a density of 8.814gcm-3
>>> % volume fraction of 0.3
>>> % mass fraction of 0.363806470697
>>> 29063.31c 0.0695231818437
>>> 29065.31c 0.0310164882122
>>> 24050.31c 0.00436844866393
>>> 24052.31c 0.0842411841431
>>> 24053.31c 0.00955227405201
>>> 24054.31c 0.00237776319682
>>> 40090.31c 0.0517276602438
>>> 40091.31c 0.0112805509803
>>> 40092.31c 0.0172425534146
>>> 40094.31c 0.0174737946557
>>> 40096.31c 0.00281511076157
>>> %
>>> % Bronze with a density of 8.8775gcm-3
>>> % volume fraction of 0.5
>>> % mass fraction of 0.610712492175
>>> 29063.31c 0.345745900177
>>> 29065.31c 0.154248170939
>>> 50112.31c 0.000255260131043
>>> 50114.31c 0.000173682151019
>>> 50115.31c 8.94726232523e-05
>>> 50116.31c 0.00382627041791
>>> 50117.31c 0.0020210286664
>>> 50118.31c 0.00637360863285
>>> 50119.31c 0.00226049951099
>>> 50120.31c 0.00857358254576
>>> 50122.31c 0.00121840660488
>>> 50124.31c 0.00152366614303Homogenised_mixture can also be formed from Compounds and Materials based on mass_fraction. The two Compounds and 1 Material are mixed with mass_fraction in the following way. This Homogenised_mixture contains 20% mass Water and 30% mass CuCrZr.
new_mat_mix = Homogenised_mixture([{'mix':mat_water,'mass_fraction':0.5},
{'mix':mat_CuCrZr,'mass_fraction':0.5}])
new_mat_mix.density_g_per_cm3
>>> 1.6759268993839835Void fractions can also be inserted into a Homogenised_mixture. In the example below, a new material is made from 50% volume fraction Nb3Sn and 50% void. The density of the Nb3Sn is specified as 8.91g per cm3 and a void is 0g per cm3. The resulting example material has a desnity of 4.455g per cm3 as expected.
mat_Nb3Sn = Compound('Nb3Sn',density_g_per_cm3=8.91)
mat_void= Material(material_card_name='Void',
density_g_per_cm3=0,
elements=[ ],
element_mass_fractions=[ ]
)
example_mat =Homogenised_mixture(mixtures=[mat_Nb3Sn,mat_void],
volume_fractions=[0.5,0.5])
example_mat.density_g_per_cm3
>>>4.455Homogenised_mixture can also be squashed which combines duplicate isotopes. This setting is False by default but setting it to true can be achieved using the following command:
mat_mix.material_card(code='serpent',squashed=True)
The material_card for Homogenised_mixture can also be producing using isotope mass fractions instead of the default isotope atom fractions. Mass fractions can be achieved using fractions keyword:
mat_mix.material_card(fractions='isotope mass fractions')
Isotopes, Elements, Materials and Compounds can all generate material cards for Serpent 2, MCNP and Fispact 2. Once your object has been created then use the .material_card() method along with optional arguments to get the material card.
Arguments can be passed to the .material_card() method or specified with the object upton creation. Permitted arguments are :
- material_card_name [string] used by Serpent,
- material_card_number [int] used by MCNP,
- material_card_comment [string]
- color [rgb tuple] used by Serpent,
- code ['serpent','mcnp','fispact'],
- fractions ['isotope atom fractions','isotope mass fractions'] used by MCNP and Serpent,
- temperature_K [float] used by Serpent
- volume_cm3 [float] required for Fispact outputs
a=Material(density_g_per_cm3=7,
isotopes=[Isotope('Sn',112),Isotope('Be',9)],
isotope_atom_fractions=[0.5,0.5])
a.material_card(code='mcnp',material_card_number=5, material_card_comment='my material',fractions='isotope mass fractions')
c
c my material
c density =7.0 g/cm3
c density =0.06972548702136161 atoms per barn cm2
c temperature =293.15 K
M5
50112.31c 0.5 $ Tin_112
4009.31c 0.5 $ Beryllium_9There are a range of ways to specify the required nuclear library for both the MCNP and serpent in a range of ways.
Applying a library to individual isotopes
Serpent and MCNP material cards can contain a pointer to the desired nuclear cross section file. The pointer is optional but if included it appears after the zaid entry in the material card. When importing neutronics_material_maker it attempts to import a default Serpent 2 xsdir file and find the preferential nuclear library evaluation for each isotope present in the xsdir. If no file is found or the particular isotope is not found then the optional nuclear library is left blank in material cards. The default path of the xsdir file is /opt/serpent2/xsdir.serp, however this can be changed using the set_xsdir(filename) function as demonstrated below. the set_xsdir method allows for the importing of an MCNP xsdir file in the same way.
from neutronics_material_maker.examples import *
example_isotope = Isotope(3,6)
example_isotope.nuclear_library
>>> .31c
set_xsdir('xsdir_TENDL.serp')
example_isotope = Isotope(3,6)
>>> .10cApplying a library to all isotopes within a material
For an MCNP material card a specific library can be applies to all isotopes within a given material using the nuclear_library=library_extension_as_string optional argument with the Material method. This will overwrite all library extensions previously set for each isotope.
from neutronics_material_maker.nmm import *
material_borated_polythene = Material(material_card_name='SWX-201 (Borated polythene)',
density_g_per_cm3=0.95,
nuclear_library='.70C',
isotopes=[Isotope(zaid='1001'),
Isotope(zaid='6012'),
Isotope(zaid='6013'),
Isotope(zaid='8016'),
Isotope(zaid='5010'),
Isotope(zaid='5011')],
isotope_atom_fractions=[6.2526E-01,
2.7189E-01,
2.9407E-03,
7.4946E-02,
4.8934E-03,
2.0073E-02
],)
print(material_borated_polythene.material_card(code='mcnp',
material_card_number=1,
material_card_comment="SWX-201 (Borated Polythene)"))
>>> c
c SWX-201 (Borated Polythene)
c density =0.95 g/cm3
c density =0.10594872766151579 atoms per barn cm
c temperature =None K
M1
1001.70C 0.6252580617000087 $ Hydrogen_1
6012.70C 0.2718891571436129 $ Carbon_12
6013.70C 0.00294069088385826 $ Carbon_13
8016.70C 0.07494576766812022 $ Oxygen_16
5010.70C 0.004893384830507025 $ Boron_10
5011.70C 0.0200729377738929 $ Boron_11Some example materials are available for importing
from neutronics_material_maker.examples import *The examples include Li4SiO4, Li2SiO3, Li2ZrO3, Li2TiO3, Be12Ti, Ba5Pb3, Nd5Pb4, Zr5Pb3, Lithium_Lead, Tungsten, Eurofer, SS316LN_IG, Bronze, Glass_fibre, Epoxy, CuCrZr, DT plasma and Void. The construction of these materials can be seen in the examples.py file
- Write MORE Tests and improve code coverage
- Add fispact writter to elements, isotopes, compounds and homogenised Materials
- Add squash option to all material cards
- Combine with engineering materials database
- Address #todo comments in the code
Isotope natural abundance and mass data from Nist
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