Does an Engineering lab need to be quantitative?





In the Fluids Engineering lab in the Diamond we have these pressure gauge calibrators. They are essentially water pistons of a known surface area onto which students can place known masses. The idea being that you can experiment with the relationship between pressure, force and area. They are a pain because they constantly leak, resulting in the force not increasing the water pressure to the correct amount, leading to inaccurate results and instead spraying all over the lab, leading to wet trousers.

I’m looking to replace these devices with something more robust. The simplest and cheapest solution to demonstrate the relationship between pressure area and force is to connect two differently sized plastic syringes and alternately press each of the plungers. A big syringe is hard to push (big area/high force) and doesn't move very far and a little syringe is easy to push (small area/low force) and moves a long way.

The problem with this approach is the amount of force required to overcome the friction from the rubber seals of the syringes. One of the reasons the calibrators leak all the time is the technical difficulty in creating a watertight seal between moving surfaces that is close to frictionless. The friction force does not contribute to the pressure in the fluid and is difficult to determine for a quantified analysis of the force/pressure/area relationship.

How critical is it for students to perform a numerical analysis after an experiment? As engineering educators who design experiments for engineering students, our default thought process is to consider the mathematical model that describes a system and figure out how to instrument our set up to demonstrate the physics. Because of this, most engineering students will do numerical post processing of their experiments ad nauseam as they progress through their diet of experimental activities in their particular programme.

Data analysis is one skill students should demonstrate they can deploy. However, there are other skills that are equally important for engineers to be able to demonstrate, such as identification of underlying principles and articulating these to others. Maybe I can simply provide the big and small connected syringes and ask student to qualify, rather than quantify the results. 

Participation in pushing a syringe may seem a trivial task that requires no specific technical skills. But what if it were coupled with a group task of discussing with their peers what has been observed, conjecturing why the performance of the system manifests in the way it does and the potential industrial engineering applications. This then arguably becomes a higher level of learning than simply plotting points on a pair of axes and drawing a line between them.

New discoveries with established methods.

 



I think this news story is absolutely great.

https://www.sheffield.ac.uk/cbe/news/cracked-cold-case-why-boiling-water-freezes-faster

I’ve long been fascinated by the Mpemba effect, where hot water can freeze faster than cold water. It’s fantastic that there still is (was?) an unknown phenomena in fields as well understood, researched and industrially relevant as heat transfer and phase change.

I once wrote an extensive technical engineering report documenting a fictitious experimental investigating the Mpemba effect, to provide an exemplar for students on how to write up. I didn’t want to provide an exemplar of an experiment that students would actually be asked to do, as there is a reasonable chance they would reword what had been supplied rather than translating the general principles of technical report writing into their own work. And it was unlikely we would ask them to do an experiment on the Mpemba effect, as we couldn't explain why it happened.

Apart from my attraction to the effect, the reason I think this story is great is the approach Professor Zimmerman took that is described at the end of the article.
 

Testing a new theory requires a prediction, and that usually means conducting new experiments. Probably like most University labs, conducting new experiments was banned in the last year, with only high priority exceptions. It dawned on me last December that I should analyse experiments already published on this topic. I did, and a prediction that my theory makes about microbubbles and dissolved gases, correlates beautifully with Mpemba and Osborne's 1969 paper."


I’ve a preoccupation with writing technical engineering reports and recording experimental findings. I’ve written a 6 week MOOC about the subject. Part of my delight with this story is it provides the perfect example of the value in properly recording what you did in an experiment and what results were obtained. Because the results of an experiment were properly documented 50 years ago, they can be used in contemporary research, the likes of which was probably unimaginable at the time.

It is sometimes hard to convince students of the value in doing things for reasons beyond their immediate benefit. They may believe they are writing up an experiment because it is required in order to demonstrate to their teacher they have performed a task in a laboratory. The real reason that we ask students to write up experiments is to teach the process for doing so and the standards that should be applied, as the documentation of work is a critical part of the engineering process. We can tell them that they may, in the future, need to refer back to their results and interpret them in new ways to discover hidden meaning, but this is a hard sell for a routine undergraduate lab class. I will now be citing this work as an example of why it is important to document findings well. And possibly to defend my disproportionate fixation with report writing and keeping an experimental record.

How do we use labs to enhance employability skills?

This blog post comes from Dr Chalak Omar, a University Teacher in MEE who leads sessions in the Diamond Pilot Plant, a realistic industrial setting experienced by our chemical engineering and bioengineering students.

Practical activities at MEE do not only involve providing hands on experience, but also the skills required to make students industry-ready. Some of our activities focus on improving the students’ employability, and help them develop the skills required in their life after the University.  A good example of this are practical activities which utilise the Diamond Pilot Plant (DiPP). The facilities at the DiPP include industrial rigs, which are used in pharmaceutical and bioengineering technologies (Figure 1). These rigs are heavily used in both undergraduate and postgraduate taught curricula to provide group-based open-ended practical sessions, which deal with up-to-date challenges in industrial settings. The skills addressed in these sessions include planning, team working, leadership, problem solving, critical analysis, time management and communication skills.

Figure 1: ConsiGma25 Continuous Tabletting line (CTL) used during the practical sessions.

The activities in these sessions are designed in a way to shift the responsibility from the teacher to the students and allow students to direct and lead their learning process. It involves providing teams with scenarios based on realistic challenges in industry. The teams start by pre-planning their sessions, identifying the parameters of interest and then setting the critical process parameters. In this stage, students have to think about their plan carefully, considering the time and material constraints, which in turn helps them develop some time management skills. 

Their next step is to attend the lab to execute the plan and collect the required data. Once in the lab, students might be required to adjust their plan as a result of the equipment limitations and their chosen parameter interaction. However, they will only find out these challenges while executing the plan in the lab. The students can then amend and improve their plan and then implement the changes during the session.

The procedure mentioned above (Plan-Do-Check-Act cycle, Figure 2) is a four-step model used as a project-planning tool that in many industries as a process for continuous improvement. The PDCA is usually used when starting a new improvement project, or working towards continuous improvement in existing projects.

Figure 2: The Plan-Do-Check-Act cycle

In addition to the project management skills gained during these practical sessions, students will also gain extensive hands on experience on how to work with and operate an industrial scale rig. The data collected from these sessions will be critically analysed by students and will be used to write technical reports, which help improve their communication skills. 

Exposing students to the PDCA process and providing them with the extensive hands-on experience with the additional skills on how to plan and conduct experiments, leadership, team working and data management and analysis will improve their employability skills and make them ready for life after University. 

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