User:Tomhubbard

Tomhubbard

This user is a Commander in the United States Navy.

UVAThis user attends or attended the University of Virginia

This user attends or attended the United States Naval Academy.

PhDThis user has a Doctor of Philosophy degree.

This user lives in or hails
from Richmond

This user has been on Wikipedia for 18 years, 8 months and 9 days.

An ancestor of this user fought for the United States in World War II.

This user has been awarded the National Defense Service Medal.

User:UBX/Commendation Medal

Per the userbox migration, {{User Christian}} was moved to {{User:CharonX/Userboxes/User christian}}.

This user has been awarded the Southwest Asia Service Medal.

About Me

I live in Richmond, Virginia in the United States of America and I like nuclear engineering, mathematics, computers, and guns.

64. Brigham Hubbard (1788-1838)

32. Erastus Willard Hubbard (1819-1902)

16. Willard Wright Hubbard (1854-1923)

33. Arabella Wright (1827-1914)

8. Willard Wright Hubbard, Jr. (1886-1969)

17. Josephine Spencer Niles (1858-1952)

4. Willard Wright Hubbard III (1915-1987)

9. Helen Motley (1887-1969)

2. William James Hubbard (1941-2020)

5. Sara Eloise Rast (1917-1993)

1. Thomas Richard Hubbard (1965-)

3. Barbara Jean Ockun (1943-)

Grandma

Willard Wright Hubbard III (1915-1987)

Mom

Dad

Uncle John

My brother Bill

Me!

My brother Jim

My brother Greg

• http://en.wikipedia.org/wiki/Omicron_Delta_Kappa
• http://en.wikipedia.org/wiki/United_States_Naval_Academy
• http://en.wikipedia.org/wiki/University_of_Virginia
• http://en.wikipedia.org/wiki/Yodle,_Inc
• http://en.wikipedia.org/wiki/ReachLocal

I am a former Senior Manager of Software Development at Amazon, where I managed the development of the amazon.com content selection and delivery software (i.e. Amabot). I also invented, designed, and developed the engineering of Amazon.com's behaviorial-targeted third-party display advertising product.

Favorite Math Equation

$\left({\frac {1}{v(E)}}{\frac {\partial }{\partial t}}+\mathbf {\hat {\Omega }} \cdot \nabla +\Sigma _{t}(\mathbf {r} ,E,t)\right)\psi (\mathbf {r} ,E,\mathbf {\hat {\Omega }} ,t)=\quad$

$\quad {\frac {\chi _{p}\left(E\right)}{4\pi }}\int _{0}^{\infty }dE^{\prime }\nu _{p}\left(E^{\prime }\right)\Sigma _{f}\left(\mathbf {r} ,E^{\prime },t\right)\phi \left(\mathbf {r} ,E^{\prime },t\right)+\sum _{i=1}^{N}{\frac {\chi _{di}\left(E\right)}{4\pi }}\lambda _{i}C_{i}\left(\mathbf {r} ,t\right)+\quad$

$\quad \int _{4\pi }d\Omega ^{\prime }\int _{0}^{\infty }dE^{\prime }\,\Sigma _{s}(\mathbf {r} ,E^{\prime }\rightarrow E,\mathbf {\hat {\Omega }} ^{\prime }\rightarrow \mathbf {\hat {\Omega }} ,t)\psi (\mathbf {r} ,E^{\prime },\mathbf {{\hat {\Omega }}^{\prime }} ,t)+s(\mathbf {r} ,E,\mathbf {\hat {\Omega }} ,t)$

Where:

Symbol	Meaning	Comments
$\mathbf {r}$	Position vector (i.e. x,y,z)
$E$	Energy
$\mathbf {\hat {\Omega }} ={\frac {\mathbf {v} (E)}{|\mathbf {v} (E)|}}={\frac {\mathbf {v} (E)}{v(E)}}$	Unit vector (solid angle) in direction of motion
$t$	Time
$\mathbf {v} (E)$	Neutron velocity vector
$\psi (\mathbf {r} ,E,\mathbf {\hat {\Omega }} ,t)dr\,dE\,d\Omega$	Angular neutron flux Amount of neutron track length in a differential volume $dr$ about $r$, associated with particles of a differential energy in $dE$ about $E$, moving in a differential solid angle in $d\Omega$ about $\mathbf {\hat {\Omega }}$, at time $t$.	Note integrating over all angles yields scalar neutron flux $\phi \ =\ \int _{4\pi }d\Omega \psi$
$\phi (\mathbf {r} ,E,t)dr\,dE$	Scalar neutron flux Amount of neutron track length in a differential volume $dr$ about $r$, associated with particles of a differential energy in $dE$ about $E$, at time $t$.
$\nu _{p}$	Average number of neutrons produced per fission (e.g., 2.43 for U-235).
$\chi _{p}(E)$	Probability density function for neutrons of exit energy $E$ from all neutrons produced by fission
$\chi _{di}(E)$	Probability density function for neutrons of exit energy $E$ from all neutrons produced by delayed neutron precursors
$\Sigma _{t}(\mathbf {r} ,E,t)$	Macroscopic total cross section, which includes all possible interactions
$\Sigma _{f}(\mathbf {r} ,E^{\prime },t)$	Macroscopic fission cross section, which includes all fission interactions in $dE^{\prime }$ about $E^{\prime }$
$\Sigma _{s}(\mathbf {r} ,E'\rightarrow E,\mathbf {\hat {\Omega }} '\rightarrow \mathbf {\hat {\Omega }} ,t)dE^{\prime }d\Omega ^{\prime }$	Double differential scattering cross section Characterizes scattering of a neutron from an incident energy $E^{\prime }$ in $dE^{\prime }$ and direction $\mathbf {\hat {\Omega ^{\prime }}}$ in $d\Omega ^{\prime }$ to a final energy $E$ and direction $\mathbf {\hat {\Omega }}$.
$N$	Number of delayed neutron precursors
$\lambda _{i}$	Decay constant for precursor i
$C_{i}\left(\mathbf {r} ,t\right)$	Total number of precursor i in $\mathbf {r}$ at time $t$
$s(\mathbf {r} ,E,\mathbf {\hat {\Omega }} ,t)$	Source term

Travels

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