Cover picture Molecule Man
Sculpture is meant by the artist to remind the viewer
"that both man and molecules exist in a world of probability and that finding wholeness and unity within this world remains the aim of any creative and spiritual tradition"
Jonathan Borofsky (1998)
A Thermodynamic Journey from Molecule
to Process Efficiency
Inaugural speech given by Joachim Groß
Professor of Engineering Thermodynamics
Mijnheer de Rector Magnificus, leden van het College van Bestuur, Collegae hoogleraren en andere leden van de universitaire gemeenschap. Zeer gewaardeerde toehoorders. Dames enHeren,
Ik zal deze inaugurele rede in het Engels houden, om een flink aantal internationale gasten vandaag tegemoet te komen.
Preamble
We need a step-change in technology !!
That is what we can read in newspapers and see in TV very often these days. It is claimed by journalists usually in the context of climate-implications of our industrial society. But is this a realistic claim? Didn’t a Thermodynamics Professor who was appointed 25 years ago (during the oil crises) have the exact same goal, namely to derive a significant improvement of our technological, industrial efficiency? I can see no legitimate trivial justification of that claim, so let’s look more closely.
The call for a step-change improvement of our technology towards a higher degree of sustainability is omnipresent. What is asked for is a significant reduction of emissions and a more responsible treatment of our natural resources. Politics, companies, and journalists alike articulate the claim.
The public echo of that claim has gained weight, with the awareness that climate active compounds in our atmosphere have unambiguously increased. The Intergovernmental Panel on Climate Change (IPCC, Chairman Rajendra Pachauri) has received the Nobel Peace Price 2007 for disseminating knowledge about this man-made climate change.
for “step-changes” in our technology is to ask: do we now have, or can we develop, new methodologies that support the appropriate developments.
Journey
I feel fortunate to work on (and with) two methodologies that facilitate and even enable a systematic improvement of our technology. The first is the field of Molecular Thermodynamics and the second is the framework of Second-Law Optimization. I will describe both fields today; in a journey that will have molecules and their interactions as a starting point and will lead us to macroscopic, optimized processes. A pathway of that journey is visualized in Fig. 1, where in the lower left corner we are concerned with intermolecular interactions. The aim is to predict properties of materials (mixtures) and the field of Statistical Thermodynamics forms the required bridge to get from molecular properties to macroscopic behaviour.
In order to get to the most efficient processes a second bridge is required, which is given by Irreversible Thermodynamics. It is a framework, where the environmental footprint of a process can be minimized.
Material Properties Optimized Processes Irreversible Thermodynamics Statistical Thermodynamics Molecular Interactions
design of smart solvents interfacial properties micro porous materials
Molecular Thermodynamics and its toolbox
Molecular Thermodynamics is what has early on attached me to my scientific work. It is a discipline comprising as a toolbox: Fluid Theories, Molecular Simulations, Quantum Chemistry and hybrid approaches thereof (Fig. 2). It allows the prediction of macroscopic behaviour of materials from molecular attributes. It is thus the framework that will eventually enable us e.g. to design the optimal solvent for an absorption process or a catalyst for a specific reaction.
and hybrid approaches of these !
Fluid Theories Molecular Simulations Quantum Chemistry
r
φ(r)
Fig. 2. The toolbox of Molecular Thermodynamics.
molecular interactions
• dispersive attractions and repulsive interactions
• electrostatic interactions (ionic charge, dipolar, quadrupolar,…)
• induced electrostatic interactions (due to polarizability)
• bond lengths, angles and torsions • associating interactions
Æ from group contribution or pure component data
Æ from QM (vacuum sufficient, as polarizability is accounted for) Æ from QM (only static polarizability
needed) Æ from QM
Fig. 3. Parameterizing Fluid Theories (and Molecular Simulations).
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0 0.2 0.4 0.6 0.8 1 xalkane P / M Pa
McLure et. al. 1997 PCP-SAFT, kij= - 0.01 PC-SAFT, kij= 0.0498 propionitrile – n-alkane, T=40°C propionitrile – n-pentane propionitrile – n-hexane 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0 0.2 0.4 0.6 0.8 1 xalkane P / M Pa
McLure et. al. 1997 PCP-SAFT, kij= - 0.01 PC-SAFT, kij= 0.0498 propionitrile – n-alkane, T=40°C
propionitrile – n-pentane
propionitrile – n-hexane
Fig. 4. Equation of states, where the polar interactions are accounted for (lines) and same model, where the polar interactions are omitted (dashed line). Experimental data (symbols).
Predicting Physical Properties of Mixtures
vacuum value
adapted from: Dyer and Cummings, JCP 2006
dipole moment μeff/ D
Pr
ob
ab
ilit
y vacuumvalue
adapted from: Dyer and Cummings, JCP 2006
dipole moment μeff/ D
Pr
ob
ab
ilit
y
Ronaldo “in surrounding” Ronaldo “in vacuum”
Dipole in liquid phase
Dipole in vacuum Dipole moment of water
Fig. 5. Behaviour of polarizable molecules in vacuum as opposed to their behaviour in a dense surrounding. Analogy (see text) to the example of Ronaldo’s behaviour.
It is very clear why there is so relatively little development work done on accounting for induced dipolar interactions (due to the molecular polarizability). It is because it is a true multi-body effect and in that character difficult to deal with. The difficulty can easily be made understood by considering our setting in this room: Understanding the interactions of two molecules can be compared to listening to the dialog of two people in this room. In order to understand polarizability we need to imagine, that everybody in this room speaks to everybody simultaneously. But that is not enough; everybody also mediates extra discussions of any pair (and triplets) of people in this room. You can probably imagine the simultaneous sound and it is clear that reducing the whole of the discussion towards defined dialogues among two individuals is a theoretically very demanding task.
1.5 1.7 1.9 2.1 2.3 2.5 2.7 0 0.2 0.4 0.6 0.8 ρ* T* polarizability α∗=0 α∗=0.03 α∗=0.06 spherical LJ fluid with dipole momentμ*2=4
ω
α
μ
μ
eff * * E 0 *, = + Wertheim (1973, 1977):Renormalized Perturbation Theory
(a multibody-theory giving expression for )E ω
molecular simulations Kiyohara,et al., JCP. 1997 fluid theory Kleiner, Gross, AIChE J. 2006 Fig. 6. Theory for polarizable substances. Comparison of new model to Molecular Simulation data for simple fluids
0 100 200 300 400 0 200 400 600 800 1000 density ρ / kg/m3 T / °C experimental data PC-SAFT PCP-SAFT 0 50 100 150 200 0 0.2 0.4 0.6 0.8 1 xAniline T / °C Alexejew, 1986 Campbell, 1945 PCP-SAFT, kij=0 PC-SAFT, kij=0.06
Water – Aniline, P=1 bar Water
Fig. 7. Polar, aqueous mixtures – a challenge for molecular approaches. Model where polar interactions accounted for (full line, no parameter adjusted) and same model where polar interactions are omitted (dashed line, with an adjusted parameter).
What is most important about all my work on polar and polarizable molecular interactions is, that now we utilize molecular parameters from Quantum Mechanics – thus from an independent source directly in the theories. In the analogy to Ronaldo, the soccer player in Fig. 5, one can say that the characterization of Ronaldo’s behaviour “in vacuum” is sufficient to predict his performance in a dense surrounding of a real match. The two enabling steps are on the one hand, there are now expressions for polar interactions that are accurate – at least for simple fluids. On the other hand, one can perform Quantum Mechanical calculations of molecules simply in vacuum and utilize these electrostatic molecular parameters directly. Because the effect of molecular polarizability is properly accounted for, vacuum properties are sufficient. This is a first sketch of the link between Fluid Theories and quantum chemistry that I have worked towards over the last 4 years, aiming at predictive Fluid Theories.
Hybrid Fluid Theory and Quantum Chemistry of solutions
however, calculated to self-consistency with all local orientational and density correlation. The solvation shell structure of water around a small amino-acid is for example resolved. The concept has so far not been used to calculate phase behaviour or other macroscopic properties, but I am currently setting up a project to do just that. As opposed to continuum solvent models, where the surrounding molecules are not in their structural arrangement accounted for, this is a very powerful concept: it provides the full density dependence of mixtures and allows for the description of solvent mediated effects. Further, I envision this to be an effective approach for studying reactions in “self-consistent solutions”.
DFT & 3D-RISM distance z local de ns ity g (r )
Gusarov, Ziegler, Kovalenko, JPC-A, 2006
• DFT calculation of molecules in
surrounding molecules
• full access to orientational interactions • the solvation shell structure
• solvent mediated mechanisms of chemical reactions
• slab geometries can be considered • consistent density, resolves conformers
⇒ “equation of state”
Fig. 8. Predicting Thermodynamic Properties with a hybrid approach of quantum mechanical DFT and with a classical Fluid Theory. A single molecule (or a small cluster of molecules) is calculated on DFT level, whereas the surrounding solution is treated with a classical Fluid Theory (3D RISM).
Complex mixtures - what can be done today?
When considering my work on predictive Fluid Theories, i.e. the work on the electrostatic interactions, you may think: it took him 4 years of work on that particular concept and it will probably take another 4 years to make it comprehensive? My answer is firstly, that it will probably take longer than that and secondly, that it may be quite surprising what can be done even today.
become possible. An account of the molecular branching has been proposed by Christian Schacht and Marta Kozlowska (both Thermodynamics, TU-Delft). Even very complex systems like the ones in Fig. 9 can be correlated with just one experimental data point. Required is one data point in order to adjust one constant mixture parameter. Once this has been done, the behaviour of complex mixtures can usually be very well extrapolated over wide ranges of conditions.
As a consequence of the strength apparent from these models, it is usually not worthwhile to measure the phase behaviour of mixtures, say at 30, 40 and 50ºC. That is an exercise that can be left to such models. What is urgently needed, however, are studies where the phase behaviour of mixtures is investigated systematically over wide ranges of conditions. Such measurements enable a broader understanding of complex fluids. Theo W. de Loos (Thermodynamics, TU-Delft) is one of the luminescent scientists working in that direction and it is a true pleasure to work with and to learn from him.
0 3 6 9 12 310 340 370 400 430 460 T/K P/ MPa 15 mass% CO2 10 mass% CO2 5 mass% CO2 2 mass% CO2 Modelling bPCP-Saft
CO2 + [MeOH + Polyglycerol, (Mw=2000g/mol), mass ratio 75:25]
PCP-SAFT
Liquid Crystals as Solvents with a solubility switch
I have started to speak about novel solvents, like the hyperbranched polymers. Generally, alternative solvents are urgently needed. That gets imperatively obvious when the energy conversion related to such solvent-based processes is singled out. The use of solvents and mainly the separation of mixtures contributes with almost 10% to the primary energy conversion of The Netherlands (200 PJ in 2002, source: ECN). The enormous energy conversion related to solvent-based processes leads a shadowy existence in the public awareness.
Liquid Crystals are substances with a molecular ordering in between crystals and liquids. The molecules show an imperfect long range order of molecular orientation (Fig. 10, nematic phase). Upon increasing temperature, however, the molecular ordering is broken and an isotropic state is attained. That phase transition sharply changes the thermodynamic behaviour with other components, much like a solubility-switch. This offers unique opportunities for example in using these Liquid Crystals as absorption liquids as recently proposed by Gross and Jansens (2007). liquid (isotropic) nematic (LC) smectic (LC)
Liquid crystals show (1storder)
phase transitions Temperature
Liquid crystals as process solvents
Orendi, Ballauff, Liquid Crystals 1989
⇒ Liquid crystals are solvents with a “solubility switch” ⇒ small ΔT are sufficient for regeneration of Liquid Crystal
1 2 3 290 300 310 320 T / K P / M P a isotropic nematic crystal PCH-5 – CO2 (3 mass% CO2)
Equation of state with LC term (no binary LC-parameter)
Fig. 11. Measurements and Equation of State for Liquid Crystal in mixture with carbon dioxide.
A conceptual scheme for an absorption/desorption process that operates over a temperature difference of a few Kelvin only is displayed in Fig. 10. The loading of a solute, say carbon dioxide, is taking place in the isotropic liquid, where the molecules have no orientational ordering. Upon temperature decrease over a few Kelvin, a second CO2-phase forms. When heat is withdrawn from the system, then
the phase transition to a liquid crystalline phase takes place and the solute (CO2) is
desorbed. Upon increasing the temperature over a small range, the isotropic liquid is recovered and can be used again for the absorption of solute.
It is a process that is not free of energetic cost. One has to provide the phase transition enthalpy. The elegance, however, lies in the temperature level at which the energy is provided and withdrawn. It is such that low quality heat from waste streams can be used for these energy intensive processes. You can also think of heat pumps for that purpose. That is a scientific domain of Carlos Infante Ferreira of the Thermodynamics-group. I have the privilege to learn from him during our exchanges and it is a distinct pleasure to work with him.
actually that of another mixture. But we did measurements for a mixture of Liquid Crystal and carbon dioxide ourselves and the measurements confirmed what we had anticipated.
Fig. 11 depicts the phase equilibrium of a Liquid Crystal with a constant concentration of carbon dioxide. The expected jump in solubility is shown by the step in the pressure of the diagram. This verifies the proposed concept although we would like to get to a more pronounced step in the future. And thermodynamics gives us a clear hint on what to change to achieve this, namely to increase the involved phase transition enthalpy of the considered Liquid Crystal.
We have used a molecular Fluid Theory to model this system and the result is displayed in Fig. 11. The result of the modelling is excellent considering that there are no parameters adjusted to mixture data and the resulting diagram is thus a prediction.
In summary we suggest Liquids Crystals as a new class of solvents, which possess a “solubility switch”. These Liquid Crystals can also be Ionic Liquid Crystals so that the vapour pressure is negligible. The awareness of Liquid Crystals being highly tuneable low/non-volatile (green) solvents, which can be tailored to particular applications, is not developed in the engineering community and as yet doesn’t find a reflection in scientific literature. The media asks for a step-change in efficiency of our technological processes. Although they did not have such solvents in mind, it is remarkable that a step-change in solubility of these solvents may lead to efficient alternatives to energy intensive industrial processes.
The mandate of a Thermodynamicist to develop novel solvents can easily be illustrated along the example of the Liquid Crystals.
Novel Process Solvents – Applications and Research
Needs
I have spoken about predicting physical properties and about designing solvents for specific tasks. With respect to the pathway of today’s journey we are thus midway (Fig. 1). Let me introduce two other examples for material properties, but now focusing on interfacial properties. Thereafter we proceed to cross the second bridge.
Interfaces
What is not broadly explored within the Mechanical and Chemical engineering community is the fact that the same Fluid Theories developed for bulk phases can also be applied to interfaces. The classical Density Functional Theory makes it possible to calculate interfacial properties, like the surface tension. Or it predicts how tensides or block-copolymers arrange at interfaces. The field has recently gained momentum, because the so-called ‘Fundamental Measure Theory’ was shown to give excellent results while being easily applicable to mixtures.
0 5 10 15 20 25 30 35 150 250 350 450 550 650 750 T / K σ / m N /m polar DFT non-polar DFT
• Fluid Theories and Molecular Simulations can easily be applied to interfaces
• this constitutes the more general case compared with bulk systems – the
extension is straight forward
• for Fluid Theories, the thermodynamic properties are obtained from the
classical DFT (Density Functional Theory)
Dapeng Cao, Jianzhong Wu, Macromolecules 2005, 971.
surface tension
water n-butane
Fig. 12. Thermodynamics of Interfaces. Surface tension of real components with the same model as applied in earlier Figures (left diagram). Adsorption behaviour of model block-copolymers in between two walls.
non-polar and a non-polar substance, respectively. The adsorption of a simple block-copolymer (or tenside) is displayed on the right-hand side of Fig. 12 and the results of the classical Density Functional Theory (lines) are found to be in excellent agreement with Molecular Simulations (symbols).
Why should the Thermodynamics of Interfaces be of importance, you may ask? In virtually all practical problems of our field, is the thermodynamics of interfaces a determining factor for the understanding, prediction and controllability of products or processes. That can be either through the equilibrium properties, e.g. for emulsions and colloidal systems or the adsorption in microporous materials. It can also be through cross-interfacial transport of heat and material as rate-determining steps in e.g. catalysis or crystallization processes.
re si st iv ity Rqq ,g as re sistivit y Rμμ ,ga s re sistivit y Rμμ ,liq re si st iv ity Rμq, liq re si st iv ity Rμq, ga s T T T T T re si st iv ity Rqq ,g as re sistivit y Rμμ ,ga s re sistivit y Rμμ ,liq re si st iv ity Rμq, liq re si st iv ity Rμq, ga s T T T T T de ns ity ρ ent ha lp y h distance z distance z de ns ity ρ ent ha lp y h distance z distance z
equilibrium profile non-equilibrium: transport resistivities
Fig. 13. Transport resistances through VL-interface (from classical DFT). The non-equilibrium transport properties across interfaces are often determining for the Second-Law Optimization (see text further below).
an exciting learning experience to regularly work with Prof. Dick Bedeaux on this and other subjects.
Molecular Simulations are straight-forwardly applied to interfacial problems and this technique has become an indispensable tool for understanding and optimizing surface properties. Nano-scaled gold particles (yellow in Fig. 14) are during synthesis stabilized by surfactant molecules. The surfactant molecules are depicted with a thiol-group in brown colour, which is adsorbing onto the gold clusters, and the alkyl tail-group is represented in blue colour. What is clear from this study of René Pool, Philipp Schapotschnikow, and Thijs Vlugt is that the surfactant has a determining effect on the geometry of the synthesised particles. The configuration of the surfactants is highly ordered, if a flat sheet surface is considered. The configuration is much less structured if a spherical shape is considered. This study has further shown, that the solvent, which is here not displayed, has a determining role and such simulations have to account for the solvent in order to be meaningful. Thijs Vlugt is an exceptional scientist and colleague and I look very much forward to our joint work.
Pool, Schapotschnikow, Vlugt, J. Phys. Chem. C, 2007, 10201
Schapotschnikow, Pool, Vlugt, Computer Physics Communications, 2007, 154
with solvent without solvent
with solvent without solvent
Thermodynamics of Interfaces – Applications & Research
Needs
Our products and processes are determined by the involved interfaces. In most cases it is the combination of equilibrium properties and of the transport of material and heat across interfaces, that determines a practical problem. A physical understanding of interfaces in non-equilibrium conditions is thus needed.
Irreversible Thermodynamics and Sustainable Processes
If we were in Thermodynamic heaven, then our processes would be thermodynamically reversible. For a continuous process that means, that no entropy is produced – and it also means that the environment is undisturbed. Real Processes very well leave a mark on the environment and the entropy production is a measure for the environmental footprint of a process. One can also say that the entropy production is a measure for the non-sustainability of a process. Admittedly it is not the one-and-only determining parameter; the toxicity of emissions for example is not measured with this parameter. But for energy intensive processes it is the determining quantity.
Irreversible Thermodynamics
• describes the transport processes leading to the entropy production • allows the calculation of the entropy production
⇒ allows the minimization of entropy production
⇒ optimizing the efficiency and sustainability of industrial processes
Entropy Production
• a reversible continuous process produces no entropy dS/dt=0; and it leaves no mark on the environment
• the entropy production of a process is a measure for its environmental footprint • … and thus for its non-sustainability
Fig.16. Irreversible Thermodynamics and the Entropy Production as a measure for the environmental footprint of a process (i.e. the non-sustainability of a process).
Having all this said about the entropy production, I wonder, why so many textbooks and experts in the field treat the subject of sustainability in qualitative terms only. A description of the sustainability is by such authors given in words rather than with equations and those engineers who design real processes are left with little more than an unpleasant feeling in the stomach. The Delft University of Technology is in that respect a role model; on the one hand in the tradition of Prof. de Swaan Arons who for example co-authored a book on this subject with much rigor. A strong role of Delft is on the other hand manifested through the appointment of Prof. Kjelstrup in the Thermodynamics group, who is a leading expert in the field. Lastly, I am now teaching this approach to graduate students in a mandatory course called Engineering Fundamentals.
Irreversible Thermodynamics – a bridge to process
efficiency
I find it instructive to give a flashlight view on two examples that were elaborated by Second-Law Optimization. I borrow material from my lecture on this subject, because the purpose of these examples in our setting today is to carve out the characteristic features of the method.
Pre ss u re / bar P res sure / bar ideal (frictio nless) ideal (friction)
single stage (friction)
ideal (frictio nless)
multiple stage (friction)
dQ dW Pext(t) T0 dQ dW Pext(t) T0
Fig.17. Irreversible Thermodynamics – simple example for the optimization of an expansion.
2 SO2 + O2 2 SO3
2 SO2 + O2 2 SO3
diagram is for given
P=const. and a
stoichiometric mixture
equilibr ium line
maximum reaction rate
T(z) or T(ξ) with min. entropy production for various inlet temperatures Tin T(z) or T(ξ) with min. entropy production
for various inlet temperatures Tin Johannessen and Kjelstrup, Chem. Eng. Sci. 2005, 3347
Fig. 18. Irreversible Thermodynamics – example for the optimization of a reactor.
The functional optimization is possible, because a detailed, local description of the entropy production is made available. I emphasise how closely this subject is related to the earlier work I have presented. If there is no solid description of the underlying transport processes, then one can not use this framework. Our work on the transport across interfaces is thus an enabling step for the future.
Further, I note, that the optimization is highly constrained. If there were no constraints, the optimization would of course invariably tell us not to operate any technical process at all. Not to operate is most environmentally friendly – it is reassuring to recover this intuitive result. However, constrained functional optimizations are mathematically demanding and the fact that we don’t teach functional optimizations in our studies is something I will address when speaking about education.
Concluding remarks on the Journey from Molecule to
Process Efficiency
Thermodynamics has as a mandate to develop more efficient processes. What is asked for is a lot: we perceive the public demand, or claim, to develop step-changes in our technological efficiency. A single break-through technology however is neither what can be expected nor what can seriously be strived for. Rather, a careful and responsible inventory of how we, in research, can serve this demand, asks for a review of the available scientific methodologies. I feel fortunate, that two powerful methodologies fall in my discipline and further, that the Thermodynamics-group in Delft is strongly positioned to sharpen, apply and promote these methodologies.
Molecular Thermodynamics allows for predicting the behaviour of mixtures in bulk phases, but also across interfaces. Remarkable developments have taken place over the last years, where the toolbox of Molecular Thermodynamics (Fluid Theories, Molecular Simulations, QM) has become applicable to complex practical problems. The work towards predictive models and methods has gained momentum. I feel that we, the Delft-group have contributed significantly to the recent developments on theoretical ground. The experimental work we are doing enables an understanding of complex substances and it is highly recognized internationally.
Predictive models are necessary because we have to address the need for designing materials for a specific task, examples are new solvents, microporous materials and eventually catalysts along with their structural properties.
Irreversible Thermodynamics provides a framework to optimize real processes from a detailed description of underlying transport processes. As opposed to a black-box analysis of exergy or just energy conversion, where parameter values can be optimized, this framework results in optimized functions, like profiles of temperature or composition.
This journey has covered seemingly broad aspects ranging from molecular properties up to an equipment and even process level. I have shown, however, that the toolbox used by the members of the Thermodynamics chair is narrow. It comprises experiments, Fluid Theories, Molecular Simulations, and Second-Law Optimization. All of these are highly interconnected and hybrid approaches are leading to advancements.
Liquid Crystals constitute a fascinating example of how a step-change in solubility may lead to a step-change in technology. It is the only promising and really new concept that I am aware of for substituting common absorption processes. But it heavily relies on the molecular design of suitable substances requiring both of the methodologies introduced here.
Good examples for the task at hand are available! As a result of the oil crises, the energetic efficiency of the chemical industry has markedly been reduced (Fig. 19). The energy conversion (mainly steam) has dropped by 49% while the production rates were increased by 45%.
Fig.19. Production and energy conversion of BASF AG after the oil crises.
The critical success factor –I am convinced– is more the will than the ability. It is a matter of closing the gap between what can be done and what is implemented. The industry has a critical role in this scheme because colleagues from industry need to do both, educating the university academics about their problems but also listening to their suggestions. And we, in academia, need to be the counterpart for this dialogue.
primary energy resources for steam generation production
electric power consumption primary energy resources for steam generation production
Education
The principles of sustainability are currently taught mainly in words and, at most, in positive of negative examples. But an education in terms of equations, providing a toolkit for addressing practical problems, is largely missing.
The language of Thermodynamics on the other hand is spoken in equations. This is fortunate, because Thermodynamics provides the framework to measure and to minimize the environmental impact of processes. This addresses one of the most important technological challenges, namely working towards a higher degree of industrial sustainability.
But when speaking about the needs of our graduates we have to collect a number of other loose ends: the field of process engineering – in fact most of the engineering disciplines – is currently in a transition period. Our graduates work on increasingly diversified subjects and in a broad spectrum of different job profiles. As an educational institution we are inclined to react by broadening the various applications in our curricula, trying to accommodate all specializations. Adding more and more application fields in our education is in my view, however not an adequate answer to the diversifying subject-areas. In contrary, I am deeply convinced that we have to strengthen the fundamental elements of our education. The basic disciplines are mathematics, physics & chemistry, and thermodynamics as you no doubt would have guessed.
If the fundamental disciplines are strengthened, then the various application areas are easily approachable and also those new disciplines that emerge in the future. This is what is unique about a university education, namely that we teach the pathway to solve problems and not only the solution itself. After all, this is the legitimization for the unity of research and education.
In the 19th century Thermodynamics has become an engineering discipline with the
Personal Concluding Remarks
Thermodynamics deals with two of the most fundamental concepts in nature, with energy and with entropy. Both, entropy and energy, are in competition and they are often loosely termed ‘cause’ and ‘chance’. Entropy, describes the principle of molecules to sample and to maximize the accessible states. If it was not for entropy, then our atmosphere for example would form a film on the surface of the earth. If it was not for energy, then our atmosphere would vanish towards space. The balance between these two principles determines nature – in the given example, the balance causes nitrogen and oxygen to form an atmosphere around the earth.
There has certainly been a lot of entropy in my personal path. That is to say there has been the stochastic (or you could say the ‘chance’) of any individual development, but also the entropic freedom given by my parents, my wife, and by my teachers and colleagues. By the same people, this entropic part in my personal development has been balanced by an energetic frame, a set of directional forces giving stability and orientation.
I obey the protocol of an inaugural speech in not giving an extended acknowledgement of this guidance and continuous support. Rather, I will address those who have accompanied me in my personal journey in a different setting later today.
Let me finish by saying that I feel blessed – for the joy I am able to experience in my field of work. Both, the teaching and the research and along with it the perspective of continuous active learning, are highly fulfilling and I am grateful to all members of this institution for trusting a central discipline of the Technical University of Delft in the hands of a young scientist and teacher. The journey through my discipline has outlined two critical methodologies that are currently vividly developing – and are suited to address immediate societal and technical needs. I have no certainty about the future, but I am committed to help and shape it through my research and through educating engineers who carry an effective scientific toolbox for developing our technology in a more sustainable manner.
