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2000
Week 36
Week 37
Week 38
Week 39
Week 40
Week 41
Week 42
Week 43
Week 44
Week 45
Week 46
Week 47
Week 48
Week 49
Week 50
2001
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Week 10
Week 11
Week 12
Week 13
Weeks 14-20

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The humidifier vendor called to let us know that contrary to what he told us last week it would not be possible to send us three new ultrasonic humidifiers. The reason being that he only had one in stock. He offered us to send three steam humidifiers instead, but we reclined his offer, partly because the centre already has several steam humidifiers in the storage, and partly because they are known to give off odour. Unfortunately, John Anderberg is the only vendor in Denmark to sell noise- and odourless ultrasonic humidifiers, so we had no choice but to order the last one in stock and then hope for the best with the existing steam humidifiers. The next day, we received a steam humidifier from John Anderberg and not an ultrasonic humidifier. The reason being that John Anderberg had tested his own ultrasonic humidifier and found that it had a production error, which caused the transformer to burn off. Moreover, the humidifiers could not be repaired until sometime next week as they had to order the spare parts from Germany. Very unfortunate! Instead, John Anderberg offered that we could borrow some pulverising humidifiers from Dansk Indeklima, which we did. Little did we know that these humidifiers were very noisy and bulky making them unfit for the experiments. So, we ended up using three steam humidifiers, which fortunately did not have any noticeable odour problems. However, they each consume 420 W, which may give a heat problem if the weather gets too warm.

Each of the 7 groups of 4 subjects started with a training session. This meant that Monday and Tuesday purely consisted of training sessions where we got to optimise the temperature control according to the subjects’ comfort questionnaires and got to practice the routines in between the tasks. Moreover, we used the training session to interview each of the subjects individually in order to get their immediate impressions to the test set-up with regard to suggestions to improvements. Another reason for the interview was to establish a “personal friendship” with each of the subjects to minimise their absence from the experiments, as they will surely find them very boring.

The preliminary training session turned out to be a very good idea, partly because many of the subjects had to get “accustomed” to the tasks. For example, some of the subjects had forgotten the technique for multiplication. And one of the subjects accidentally added the numbers instead of multiplying them. Moreover, some of the subjects commented on some annoyances about the test set-up, which could be improved before the real experiments started. Some of these comments related to the noise level, ergonomics and key-board standard. Moreover, a considerable amount of subjects complained of cold feet and calves even though they used the supplementary socks. This led us to buy 4 pairs of knitted leg warmers and this seemed to solve the problem. A training session can thus be highly recommended.

We started the week by buying 41 packets of Digestive biscuits, as these along with water are served the subjects during the experiments. We estimated that the subjects would devour about a third of these, which left the rest to us. A simple task, as we wouldn’t have time to cook during the experiments.

We found that with cold weather around 0°C it was not problem to cool the field lab to have an air temperature below 18° C in the workstations. It was difficult to keep the hands of the subjects warm – but this was both a problem at the hot and cold condition. In fact, the fingertip measurements showed that some subjects were able to get finger temperatures that were lower than the room temperature. A bit surprising - and mysterious! The phenomenon will be examined further when the pictures from the heat cam (thermographic camera) are analysed. So far, a big temperature drop from the palm of the hand to the fingertips has been observed on some of the subjects.

The experiments run in two sessions of 3 hours each day – also in the weekends. So it is a lot of work and hard psychologically not to have any days off!