I have a MSc in physics from the University of Oslo and a PhD in control engineering from NTNU in Trondheim (mainly modelling, I am not much of a control engineer). My main interests are mathematical modelling, numerical methods, and thermodynamics. I worked in the petroleum and chemical process industries for some 35 years and I am now semi-retired

Submitted

Thermodynamic models and tools for H2O, H2, CO2 and Air

Tool for effective thermodynamic calculations. Includes high-accuracy thermodynamic models for H2O, H2 CO2 and Air.

2 days ago | 14 downloads |

Submitted

Curvature of a 1D curve in a 2D or 3D space

Calculates the local radius of curvature as well as the cumulative arc length and the curvature vector along a 1D curve in 2D or...

12 days ago | 105 downloads |

Solved

Project Euler: Problem 4, Palindromic numbers

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

27 days ago

Solved

Project Euler: Problem 3, Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number being input, input might be ui...

1 month ago

Solved

Project Euler: Problem 1, Multiples of 3 and 5

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

1 month ago

Submitted

test_derivatives

Tool to test analytical against numerical derivatives.

3 months ago | 3 downloads |

Solved

Project Euler: Problem 6, Natural numbers, squares and sums.

The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

3 months ago

Solved

Sum all integers from 1 to 2^n

Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.

3 months ago

Solved

Square Digits Number Chain Terminal Value (Inspired by Project Euler Problem 92)

Given a number _n_, return the terminal value of the number chain formed by summing the square of the digits. According to the P...

3 months ago

Answered

Increasing precision of second order boundary value problem

Your asymptotic expansion solution seems to have zero slope at y = 0. This implies that the second derivative is zero and the s...

Increasing precision of second order boundary value problem

Your asymptotic expansion solution seems to have zero slope at y = 0. This implies that the second derivative is zero and the s...

3 months ago | 0

Solved

Place wastewater treatment processes in the correct order

There are many technologies for treating wastewater. For example, grit chambers are used to remove heavy solids, filtration is u...

3 months ago

Solved

Maximize the production in a plant within equipment capacity

The goal of a certain manufacturing company is to maximize its production of goods per day. In the production flow, there is a s...

3 months ago

Solved

Trace the path of a harmful chemical in an ecological network

An ecological network consists of the cycles of nature, such as the water cycle, the carbon cycle, the oxygen cycle, etc. Due to...

3 months ago

Solved

Count the number of reaction chains achievable in T mins

This problem is related to Problem <45467>. Let's denote a list of *N* compounds as 1, 2, ..., *N*. You are then given a list...

3 months ago

Solved

Find the fastest reaction chain to reach a target compound

This problem is related to Problem <45470>. Let's denote a list of *N* compounds as 1, 2, ..., *N*. You are then given a list...

3 months ago

Solved

List the households affected by leaks in water distribution

Consider the following water distribution network, where water is pumped uni-directionally from left to right: 8...

3 months ago

Solved

Design a minimum-cost cable network for a power grid

You are given the 2-D point locations ( _xi_ , _yi_ ) of *N* _components_ of a power grid. These _components_ include power sour...

3 months ago

Solved

Propagate the effects of a blockage in a chemical plant

From the perspective of flow, a chemical plant can be described by a collection of _nodes_ and _edges_. _Nodes_ are points where...

3 months ago

Solved

Pitting corrosion on a metal plate: Find the largest pit

You are given an N x M matrix of _ones_ and _zeros_, which represents an image of a rectangular metal plate taken from the hull ...

3 months ago

Solved

Pitting corrosion on a metal plate: Count the number of pits

You are given an N x M matrix of _ones_ and _zeros_, which represents an image of a rectangular metal plate taken from the hull ...

3 months ago

Solved

Better Index Number

Let's say you want to save many, many files and append these files with a certain sortable index number. As you probably know, y...

3 months ago

Solved

Smallest n, for n! to have m trailing zero digits

For given positive integer n, its factorial often has many trailing zeros, in other words many factors of 10s. In order for n! t...

3 months ago

Solved

Whole Number Un-Concatenator

Write a function that accepts an integer and an index digit and returns a vector containing two integers which are the leading a...

3 months ago

Solved

Whole Number Concatenator

Write a function that concatenates whole numbers. For example: numcat(111,222) should return 111222 numcat(1,2,3,4,5) s...

3 months ago

Solved

The number of trailing zero digit of a factorial

For given positive integer n, take factorial of that number. How many trailing zeros does it have? Example: factorial(11) = 3...

3 months ago

Solved

The last non-zero digit of a factorial

For given positive integer n, what is the last non-zero digit of n!? Example: factorial(11) = 39916800 Last non-zero d...

3 months ago

Solved

Permutation Via Multiplication

Given two numbers a and b, determine if the product ab is a permutation of the digits of a. For example, this is always true for...

3 months ago

Solved

Lunar Arithmetic (Multiplication)

<https://oeis.org/A087061 OEIS link for a description of lunar arithmetic> Simply take the larger digit when adding and take ...

3 months ago

Solved

Lunar Arithmetic (Addition)

<https://oeis.org/A087061 OEIS link for a description of lunar arithmetic> Simply take the larger digit. Example 1: ...

3 months ago

Solved

Muphry's Law of MATLAB

You're running some simple multiplication problems through MATLAB for error checking purposes, but nothing seems to come up with...

3 months ago