This website, which I started in 1998, has since spanned problems essentially related to courses I have taught, as "Operational Research", "Quality Control", "Computing". In its pages, I have tried to keep a coherent style, although time has led to some inconsistencies.

Some examples are mentioned below, but many other problems are solved. The website and the problems handled have as objectives:  (a) to be didactical, serving as computing aids for the pupils;  (b) to emphasize the pertinence of the Internet for Computation;  (c) to assist in my research studies; and  (d) to showcase the possibility of solving problems to anyone visiting the webpages, namely, from Industry.

The objectives above have scarcely been met, which causes concern in our technological era. A remarkable exception to this general situation is the work of Prof. V. M. Ponce (see below), acquainted to IST, whose work (since 2000) in Hydraulics I came across.

Miguel Casquilho^* — Dept. of Chemical Engineering, IST, University of Lisbon
^*Assist. Professor, retired (2012)

•  Shewhart X-bar & R control charts (Quality Control: control charts)

A control chart (invented by W. A. Shewhart) is a statistical tool to verify whether a manufacturing process is in control.

•  AS by variables: decision (Quality Control: acceptance sampling)

Acceptance sampling (AS) is a statistical decision tool for inspection of lots in order to verify their quality (fraction defective).

•  Bag filling (Quality Control: materials handling)

Filling a bag with a predetermined weight (e.g., 2 kg of oranges) is an improbable task. The costs of (i) truncation of the input population, (ii) recycling, and (iii) scrap can be computed and eventually optimized for minimum cost.

•  Catenary with concentrated loads (Civil Engineering, in collaboration)

Computes a (simplified !) model of the Lisbon suspension bridge (to Almada).

•  Iodine clock reaction (Chemical Engineering)

This reaction provides a chemistry experiment in which one can visualize how different rate constants in consecutive reactions affect the concentration of species during the reaction.

•  Roots of polynomials: Durand-Kerner (Mathematics)

Finds the (real or complex) roots of a polynomial with real coefficients, iteratively (Kerner).