Ask a Scientist: Simulations

Question:

For education purposes, I want to simulate an ultrasound and an x-ray (individually) passing through material such as a weld. I have been looking at ray tracing. Where would you suggest I begin? Also is there any funding available for such a start-up?

Response by Paul Labbé:

According to our experts in the field it is difficult to obtain this type of simulated assessments using low cost simulations. This question might be related to critical studies on safe encapsulation of nuclear waste and if so the approach needs a high level of accuracy, repeatability and be accredited by related decision makers and agencies. Additionally, aging of weld, bond and material can get very difficult to predict.

In short, it is possible to use simulation (could use ray tracing or method of moment) of an ultrasound and an x-ray (individually) passing through material such as a weld to predict the degree of usability of such techniques to detect defects. But, depending on the level of accuracy, it appears to be difficult to do so thus far and will require substantial experimentation to perfect and calibrate using real material and instruments (ultrasound and x-ray (individually) passing through material). Currently there are many instruments that can measure accurately such defects so a good approach could be to combine simulation capabilities with real trials with appropriate instruments.

Please consider the following references: NDT | NRC | K Labs

If there is funding for a start-up, National Research Council Canada would be in a better position to provide you with details.

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Ask a Scientist: Cardiac Pacemaker

Question:

Hello, Can you please tell me how I can create a fake cardiac pacemaker so that it acts like a real cardiac pacemaker? Thank you

Response by Eilean McKenzie:

In response to your question we received a solution that should be manageable for a 10 year old. Please follow the attached diagram while reading the description.

Pacemaker

What your son needs to build this model are 3 D cell batteries lined up end to end (positive-negative-positive-negative-positive-negative) probably taped together to ensure they stay in contact. Then connect one end with copper wire to a lead on a push button (he’d have to buy this, probably at The Source or Radio Shack?). A second piece of copper wire has to be wound around a nail and then you need to connect one end of the wire to the batteries and the other end to the push button. Next to the head of the nail is a washer, on a flexible rod and base. As the student presses the button, a magnetic field would be created around the nail and will attract the washer. Essentially, the student is acting like the circuit board on the pace maker and detecting an irregular or absent cardiac rhythm. By pushing the button, the “computer” (student) is sending an electrical output to the heart (the washer on the rod) and resetting the rhythm.

Alternatively, he could attach the copper wires to a small light bulb and the bulb will light up each time the student “shocks” the heart.

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Ask a Scientist: Particle Sizers

Question submitted by Tim D:

What is a particle sizer and how does it work?

Response by Ian Droppo:

A particle sizer provides scientists with information on the whole range of particles that may be in a sample. The sample could be, for example, a dry industrial powder, a soil sample, or particles within a water sample collected from a river or lake. Often particle size is required to help understand a chemical reaction, or the settling or transport of particles and their associated pollution within a natural (e.g. river) or engineered (e.g. sewer) system. There are many different types of particle sizers. The most common particle sizers use particle settling velocity, lasers, microscopes or electrical resistance to measure the size range of particles in a sample. Generally the output from a particle sizer will be called a “sediment or particle size distribution”.

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