Coming soon – Design Imagery!

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One of the failings of this blog is that it is hard for me to describe in words how the olfactometer is going to look, and the principles behind its design. Frustratingly, one of my personal weaknesses is that I am not great at drawing things on a computer!

Fortunately this is where the outreach is paying back! Dave, the aforementioned oil and gas engineer, has offered to work through the design with me in Auto CAD Inventor. Depending upon his availability, and the time that he can afford to donate to the project, I will be able to convey the design far more satisfactorily. We will start with 2 dimensional outlines but potentially can go through to 3d animations even showing the airflow details!

We are going to meet up for the first session this weekend, so I hope to have something to share early next week.

As always please leave a comment or ask any questions that you may have! (Click the “Leave a reply” link below).

A round-up of early meetings

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To my mind, the difference between lecturing an audience about a project and true outreach is accepting feedback from the audience, and allowing that feedback to improve the final outcome. Having a conversation about the choices that are made in the project, and being able to objectively defend and explain them, can only make for stronger science leading to increased confidence in results.

One of the very first people that I reached out to is an oil and gas engineer, whose day to day work focusses on piping, filtration and transit of fluids. He is, therefore, something of an expert in many of the mechanical aspects of olfactometer, although he tends to work on a somewhat larger scale! Once we had arrived at a common language, him not blinding me with fluid dynamics and me not retaliating in Latin binomials, we were able to have a productive series of meetings which went a long way in shaping my initial thoughts on how this machine should operate.

These meetings were particularly useful when digesting some of the more technical papers on dual-choice olfactometer design.

special interest lecture screen grab

In March 2014 I introduced the project to, as then, first year undergraduate biological sciences students. This introduction was simply a 5 minute slot within a lecture that I was giving. I was very pleased that some students expressed an interest in taking part in the project workshops. Unfortunately, due to the time in the semester in terms of the student’s examinations and deadlines it was the wrong time to schedule these workshops. These workshops will now take place early in the autumn semester, reviewing the design and build process, and working on the testing and experimental design.

PG meeting screen grab

 

A landmark meeting took place at the start of May 2014, where I was able to get a group of my fellow PhD students to discuss the project direction. Following an initial introduction and outline of my early design there was well over an hour of discussion, diagramming and gesticulation. All helping to further refine and define the design. Perhaps more importantly, the meeting started a long running conversation, I can bring up this project with any or all of these postgrads and they know exactly what I am talking about and can get straight into the meat of the issue at hand.

 

What is a Dual-Choice Olfactometer?

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In simplest terms a dual-choice olfactometer is a piece of experimental equipment which allows the testing of the apparent preference of one odour against another, as shown by the organism “choosing” which smell to approach. This choice is assessed by observation of the behaviour of the organism within a choice arena or chamber.

It therefore needs to be an enclosed space where organisms can be presented with a choice between two odours. These odours may be two different added odours (variables), or there may only be one odour added which is tested alongside a control where no odour variable is offered. By carefully designing a strategy of testing the variables against a control, and also against each other, it is possible to develop a data set which indicates which variables are most preferred by the organism.

Dual-choice olfactometers are designed to minimise the possibility of other factors influencing the observed behaviour. If behaviour is being influenced by other factors then little confidence can be placed in the experimental outcome. For example, if the organism can see the source of the odour it may prefer the sight of the source, so this would no longer be a test of olfactory driven behaviour. Similarly, if the air flow through the variable delivery system is unbalanced then the organism may prefer the higher or lower air flow and make its choice based upon this mechanism. Special attention is therefore needed to “design out” these potential confounding variables, and “dry-runs” where no variables are loaded will help to spot any bias in the system which can be remediated.

So far I have only referred to “the organism”. This is because we can, in principle, make this type of choice arena for any organism that has a sense of smell and can display a behavioural response which indicates preference, where one exists. Humans regularly take part in odour preference studies, particularly in areas such as perfume development, although we are able to communicate preference in more ‘intelligent’ ways than just pointing at or moving towards the favoured smell.

Adult female mosquito

Adult female mosquito

Obviously, for this project the organisms being studied will be adult mosquitoes, which have a history of being involved in olfactometer studies. In the next blog, I will look at some of the designs that have been used previously, and discuss the results of a design workshop that took place a few weeks ago.

Thanks for reading, and please ask questions or leave a comment below.

 

Olfactometer Design and Build Workshop Series Introduction

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Introduction

Thanks for visiting the blog for my olfactometer design and build project.

Below you can see the introductory video for the project, which gives a brief overview of what you can expect to see on this site and in the subsequent videos. It is my intention that this blog is readable by everyone with an enquiring mind, so please let me know if I am using too much subject specific jargon or terminology without properly explaining what I mean.

With that in mind, the next blog entry will focus on what a dual-choice olfactometer actually is and how they work.

Please leave comments, suggestions and questions using the interface below.