Categorie archief: Profi

Another teaching method: Advanced Interfacial Engineering

It was a bit of a shock to find out, when I returned after a prolonged hospital period, that “my” course – at least content-wise – was superseded by one that had more credit points and was obligatory for a larger group of master students. I taught that course, Interfacial Engineering, for almost ten years to great satisfaction of the students as well as of me. But then I realized that that was just the way things had to go: it proved such a course was a necessary contribution to the curriculum. Subsequently, I found out that the course I was originally teaching was still scheduled so that this actually was offering an opportunity that I could hardly have dreamt of. It did not take me long to realize that with one word difference in the name I could make the course into an interesting exercise that I was hoping to do once. I re-baptized the course into Advanced Interfacial Engineering and set out to organize it.

Why such a course?

Industries typically encounter heavy competition in their fields which calls for continuous innovation and fast implementation of novel technologies. Market pull is creating enormous pressure on industrial Research and Development (R&D) departments who must rapidly respond to meet customer needs. Such pressure generally hampers in-depth research activities that lead to new innovations. Instead, industry will tend to use trial-and-error strategies which generally lead to marginal product improvements. On the other hand, the R&D researchers are mostly relatively broadly trained and have limited in-depth knowledge on the problems at hand. A typical situation in industry  is that a particular product may involve some issues associated with the formulation (the right side of the below figure). Many ostensible solutions are available, for instance from literature or empirical knowledge, and the only way to determine which is best is to evaluate all of these possibilities using the few available academic contacts.


European academic research is thriving, with excellent scientific outputs and international standing, which is largely due to the active and fruitful interactions between researchers in the field. Being largely driven by curiosity, researchers are relatively specialized and have limited knowledge on the more practical aspects of product formulation. Once a new phenomenon is discovered, or a new physical insight is gained, it is understood that this discovery or physical insight can provide important solutions to real-world problems, as illustrated on the left side of the above figure. The only way to determine which problems might be solved is trying to interest relevant industries through contacts. Such contacts between academia and industry are however limited and shrouded by confidentiality agreements, a phenomenon abhorred by scientists who prefer an open exchange of ideas as is common to scientific conferences.

The gap between the strong academic research and the highly demanding market challenges can be bridged (bottom of figure) by closely matching the needs of industry and the knowledge and expertise of academia. The design of this course has been optimized to achieve this goal by (1) extracting the engineering aspects from articles and lectures, (2) formulating the essential formulation rules of an innovation and combining these with existing ones and (3) discussing these rules with the inventors.

Design rules

The important engineering issue is: how does one come from an idea, as appeared for instance in the literature, to a product.  In general one would try to find a recipe but the disadvantage of such an approach is that this would result in one single example only, if at all. And usually not a very appropriate example at that.

Here, the answer to this question would be to distill from the literature the design rules that are needed to make the product. An example: Suppose a new product could be developed with the help of an emulsion. To make it non-transparent but non-creaming or sedimenting, the droplet size would have to be of the order of micrometers. The internal non-aqueous component and the external aqueous component are defined, for instance for its farmaceutical applications. A stabilizer would be needed to maintain colloidal stability, but how much? The rule to design such an emulsion would provide that: in the case at hand one would have to calculate the specific interfacial area of the emulsion and find the number of moles of stabilizer that would be needed to coat this interface. Added a little bit that goes in the continuous phases and one has the design rule for this emulsion.

Such rules are usually not provided by the scientists that wrote down their new idea and that would be tested for applicability in a product. It would have to be found by the engineer who got the task to do the test for applicability. This requires decent knowledge of the topical matter, here colloid and interface science, and some skills in assessing scientific literature and discussing with scientists.

Course set-up

With this plan in mind I looked up some recent papers on potential topics and I chose those  which I knew I could convince the main authors to give a colloquium in our Chemical Engineering department as well. I selected Aqueous Two Phase Systems (ATPS), Waterborne Coatings, Micro-archtectures and Recyling Metals Using Complex Fluids. I added one of my own topics, to be sure there would be enough material, it would be Wet Nanoparticle synthesis. Each of the topics would require some introductory theory – to be provided by myself, an assessment of the article chosen, participation in the colloquium and a final discussion with the speaker and main author of the article. On each topic a report had to be produced which would give some design rules and some general assessment regarding the suitability for further development into a product.

1 Introductory material

As a senior lecturer on the topic I command a realm of lecture material  to illustrate all aspects of  a particular topic. Nevertheless, the preparation of the introductory material calls for some care, as it is important to use the occasion to teach at the same time how to extract design rules such that the students can see how this is done. For instance, in lecturing on the general principles of ATPS special attention is directed towards the stability condition: can one formulate a preferably simple rule by which one may decide whether a system will phase separate or not (answer: Yes)? And are there more rules that need to be taken care of?

The second important aspect is to demonstrate the general principles behind the rules: what is the fundamental reason for its existence (answer: 2nd Law of Thermodynamics)? The reason for this should be clear: we only have a limited number of general principles whereas there is an overwhelming lot of rules that can be derived from that! Unfortunately, this is not current practice in engineering. It is , however, absolutely necessary to do when entering product design. A limited number of general principles behind a topic allows one to develop creative solutions.

2 Article assessment

Reading a scientific article is for students one of the most difficult tasks to have. The reason is that it is not at all clear what should be the result of this task. Therefore a set of questions is formulated that has to be answered on the basis of the article and the instructor should make clear how to find the answers. This item is very much appreciated by students and I have been teaching this over and over with great success.

The questions for the present course would be

  1. What is, in your own words, the main issue of the paper?
  2. What are the main claims or conclusions of the paper?
  3. Are the scientific / experimental arguments provided in the paper sufficient to support the conclusions? Are there flaws in the reasoning?
  4. If you were to decide on the future direction of a company for which the results of this paper could be relevant, would you
    • discard the paper,
    • try to find an academic group that would further investigate the claims of the paper,
    • have some of your own research team further investigate the usefulness to your company, or
    • immediately try to adapt the processes in your company to implement new technology?

Important to realize is, that to do this assessment it is NOT necessary to read the full article. Skimming is sufficient with subsequent reading of the parts that are of interest. Note, that a good scientific paper has not been written from top to bottom. One typically starts at formulating a conclusion based on the experimental or theoretical evidence that has been collected; one aims for a one-liner. A discussion section is then written to end in the conclusion and an introduction is written to explain why the conclusion is interesting. The technical sections, materials and methods and results, could have been written at any time but usually near the end so that the aim of the data is clear.

A scientific article with (my) assessment is available here for further study. The article it refers to is by Gracia et al and published as Anal Chem 71 (1999) 256-258. I find it important to stress that this is just an example and there are many articles that could be commented on likewise. Important to convey to the student is that every answer to a question can never be a single yes or no, or a number, or whatever. Scientists answer with arguments and so an answer should read like, yes, because … . In the case of the answer being numbers the range of values in which these should fall (order of magnitude) and error estimates should be mentioned. Let us go through the questions one by one.

The first question, about the main issue, is a tricky one. One would be tempted to take the title of the article for that. But many times the title is formulated to attract the attention but does not cover the topic of the article. Usually, the abstract gives sufficiently detailed information on what actually has been done. But many times, the section before the conclusion that wraps up the obtained results is a good one to look at

The second question is about the main claim or conclusion. One should find the conclusion (note the literal  meaning of the word) at the end of the paper but unfortunately, most people conclude with a summary in the form of  a collection of facts. The conclusion should be an inference drawn from these facts but it may very well be missing. In that case, the authors are satisfied by just listing what they have done and leave the inference to others even though they were in the best position to do draw a conclusion.

I always enjoy discussing the third question: could there be flaws or even errors in scientific articles. The answer is an eye-opener to students. Obviously, the answer is YES and not so few either. Many are harmless but sometimes it is obvious that the conclusion is based on wrongly interpreted evidence (see example). How does a beginning student find these? Well, the evidence of the authors is in graphs and tables for experimental papers and in resulting formulae or numbers for theoretical articles. These results should immediately lead to the conclusion, given some discussion, but the authors will have done their best to select the results optimally to achieve their goal. This, the students should be able to follow. But sometimes formulas can be proven wrong by a simple dimensional check, or a number does not fall in the range of values that one would expect, or graphs do not show Gaussian noise (given noise in data, no more or less  than 2/3 of the data points can fall on a regression line). It even happens that a graph does not show what its legend promises (see example) .

The last question is really relevant and the student should provide the arguments for his decision, thereby noting the increase in investment and in risk of the four choices.

3 Questioning during colloquium

Despite the fact that the students were well geared up for the colloquium, it turned out to be difficult to challenge them into questioning. This probably had to do with the fact, that the lecture material was more mature than the article they studied and so contained many items that were still new to them. Yet, some did pose a question (I myself was discussion leader during the colloquium) and did get answers but very likely not the answer they were after. That was a good lesson: speakers evade difficult topics when questioned.

4 Discussing with scientist

But after the colloquium, when their scheduled lectures were over, the students took the chance to really get at the speaker and each of them asked the questions they prepared and pushed until they had the answers they wanted. Both speaker and students enjoyed this a lot, that was clear.

5 Report

The outcome is a detailed report of their work on the topics with some design rules – with scientific underpinning – an assessment of the scientific article, of the lecture and of the discussion. This was repeated 5 times so that all of them were well trained near the end of the course. It was therefore appropriate that the last speaker was a senior one and one that was well-seasoned in dealing with complex situations.

ThankYouIt was a bit embarrassing that the students had decided to thank me for teaching this course and handed me – in the presence of this colleague –  a good bottle of wine (they know I appreciate this). On the right side a painting of van ’t Hoff, a very appropriate icon in this respect (see his inaugural lecture here).

Testimonials of the students:

Greet: I really liked the set-up of the course. Through the papers all theory in the course gets relevance. Even though I am not a chemist, I got a good grasp of concepts that were dealt with in the course. I would recommend this course for PhD students as well because of the paper set-up.

Sameer: If I wish to summarise the takeaways from the course of Interfacial Engineering then I would definitely say that I learnt a new approach for looking at the literature work. The guidance which you provided throughout the course enabled me to understand how one is expected to analyse and interpret the principles that are discussed in publications. One more important thing I would like to mention here is that I liked the idea of having meetings with authors, who are eminent figures in their respective domains to discuss their own literature. It was really new experience to hear them personally. This course helped a lot in enhancing my knowledge regarding many phenomes especially surfactants and microstructure.

Carolina: A course that covers interfacial engineering matters through the analysis of novel researches in the field. An opportunity to discuss issues regarding interfacial engineering with its authors. A original teaching method that reduces the gap between students and scientific research.

Shwet: The course was really interesting and I learnt lot of new concepts about surfactants, micro structure, Aqueous two phase systems (ATPS) etc. and specially how to interpret the conclusions of a research paper and to scrutinize the research presented in the paper. The colloquium gave me to rethink on certain issues as the work presented by researchers was outstanding. I would suggest this course to the students who are doing research so they can have a better understanding not only about Interfacial engineering but also about how to deduce the main conclusions of a paper . The meeting with the authors and discussing about their research was a good way to learn from them and also to have a better idea about their research work.

How to plan your research project?

Quite some years ago I wrote the below instructions on how to plan a research project, largely because there was no practical guide that I could advise. Suggestions from colleagues have been added here and there. These instructions should prevent students from getting significantly delayed just because of having the wrong ideas on project management in mind.

Despite being written already quite some time ago, the instructions are still quite up to date. Therefore, Lees verder How to plan your research project?

Een gemiste kans?

Een artikel over een alledaagse toepassing van de Thermodynamica trekt altijd mijn aandacht. Zo ook het artikeltje met de uitdagende titel De wet van eraf en eraan in de NRC-column (6 juni 2015) van Martijn Katan. Hij gaat met dat artikeltje in tegen de naar zijn mening foute redenering van “… diëtisten en professoren …” dat een gewenste hoeveelheid van je gewicht verminderd kan worden door gedurende een bepaalde tijd minder te eten totdat die hoeveelheid door inspanningen is verdwenen: een balans van voeding en activiteiten. Hij refereert daarbij aan bevindingen van de fysicus Kevin Hall die werkzaam is bij het Amerikaanse Instituut voor Gezondheid, de NIH. Het onderzoeksprogramma van Hall is gericht op het wiskundig formuleren van metabolisme zodat daarmee het lichaamsgewicht onder allerlei omstandigheden voorspeld kan worden. Hall heeft inmiddels een applicatie voor intelligente telefoons uitgebracht waarmee dit idee door iedereen gebruikt kan worden. Lees verder Een gemiste kans?