Search results

Moderne verspaningstechnieken

In deze publicatie wordt een 'tool' aangeboden om tot een gestructureerde selectie, keuze en implementatie van innovatieve verspaningstechnieken te komen. Deze tool is ontwikkeld in het kader van het project "Procesinnovatie Verspaning voor MKB-bedrijven".

Myths and fallacies in the Groningen earthquake problem

I was somewhat surprized with the fog in Groningen upon my arrival. This is notthe fog that covers the beautiful landscapes of the northern Netherlands in theevening and in the early morning. No… It is the fog that obscures the real aspectsof the earthquake problem in the region and is crystallised in the phrase “Groningen earthquakes are different”, which I have encountered numerous times whenever I raised a question of the type “But why..?”. A sentence taken out of the quiver as the absolute technical argument which mysteriously overshadows the whole earthquake discussion.Q: Why do we not use Eurocode 8 for seismic design, instead of NPR?A: Because the Groningen earthquakes are different!Q: Why do we not monitor our structures like the rest of the world does?A: Because the Groningen earthquakes are different!Q: Why does NPR, the Dutch seismic guidelines, dictate some unusual rules?A: Because the Groningen earthquakes are different!Q: Why are the hazard levels incredibly high, even higher than most Europeanseismic countries?A: Because the Groningen earthquakes are different!and so it keeps going…This statement is very common, but on the contrary, I have not seen a single piece of research that proves it or even discusses it. In essence, it would be a difficult task to prove that the Groningen earthquakes are different. In any case it barricades a healthy technical discussion because most of the times the arguments converge to one single statement, independent of the content of the discussion. This is the reason why our first research activities were dedicated to study if the Groningen earthquakes are really different. Up until today, we have not found any major differences between the Groningen induced seismicity events and natural seismic events with similar conditions (magnitude, distance, depth, soil etc…) that would affect the structures significantly in a different way.Since my arrival in Groningen, I have been amazed to learn how differently theearthquake issue has been treated in this part of the world. There will always bedifferences among different cultures, that is understandable. I have been exposed to several earthquake engineers from different countries, and I can expect a natural variation in opinions, approaches and definitions. But the feeling in Groningen is different. I soon realized that, due to several factors, a parallel path, which I call “an augmented reality” below, was created. What I mean by an augmented reality is a view of the real-world, whose elements are augmented and modified. In our example, I refer to the engineering concepts used for solving the earthquake problem, but in an augmented and modified way. This augmented reality is covered in the fog I described above. The whole thing is made so complicated that one is often tempted to rewind the tape to the hot August days of 2012, right after the Huizinge Earthquake, and replay it to today but this time by making the correct steps. We would wake up to a different Groningen today. I was instructed to keep the text as well as the inauguration speech as simple aspossible, and preferably, as non-technical as it goes. I thus listed the most common myths and fallacies I have faced since I arrived in Groningen. In this book and in the presentation, I may seem to take a critical view. This is because I try to tell a different part of the story, without repeating things that have already been said several times before. I think this is the very reason why my research group would like to make an effort in helping to solve the problem by providing different views. This book is one of such efforts.The quote given at the beginning of this book reads “How quick are we to learn: that is, to imitate what others have done or thought before. And how slow are we to understand: that is, to see the deeper connections.” is from Frits Zernike, the Nobel winning professor from the University of Groningen, who gave his name to the campus I work at. Applying this quotation to our problem would mean that we should learn from the seismic countries by imitating them, by using the existing state-of-the-art earthquake engineering knowledge, and by forgetting the dogma of “the Groningen earthquakes are different” at least for a while. We should then pass to the next level of looking deeperinto the Groningen earthquake problem for a better understanding, and alsodiscover the potential differences.

Een nieuwe kijk op Lastmile planning : eerste inzichten en ideeën uit het project Lastmile.info.

Myths and fallacies in the Groningen earthquake problem

KNAW – minisymposium ‘Aardbevingsbestendige woningen’ 24 maart 2020Ondanks absentie van het symposium door de Corona crisis is dit boekje samengesteld voor digitale verzending en het drukken van een papieren versie.

Smart industrial safety and worker health:

Onze leef- en werkomgeving heeft invloed op onze gezondheid, maar het nauwkeurig bepalen van persoonlijke blootstelling aan verschillende milieufactoren blijft een uitdaging. Toch is dit wel van belang, omdat bijvoorbeeld de blootstelling aan fijnstof, stikstofdioxide en ozon jaarlijks al leidt tot 12.000 vroegtijdige sterfgevallen in Nederland (Gezondheidsraad, 2018). In werkomgevingen zijn er behalve voor de genoemde stoffen ook nog andere vluchtig organische stoffen en chemicalen waarvan de blootstelling op de korte of lange termijn tot negatieve gezondheidseffecten kan leiden. Ook fysische blootstellingen kunnen negatieve gezondheidseffecten hebben, zoals geluid, UV-straling, elektromagnetische velden en trillingen.

Thermo-elektrische materialen

Thermo-elektrische materialen zijn al sinds de 19e eeuw bekend. In 1834 ontdekte de Franse natuurkundige Jean Peltier dat er warmte wordt getransporteerd van de overgang tussen twee metalen wanneer er een elektrische stroom vloeit door het grensvlak. Het grote voordeel van Peltier elementen is dat er geen bewegende delen of vloeistoffen in zitten, waardoor het onderhoudsarm en stil is. Nadeel is het lage rendement (<10%) van deze materialen. Grootste uitdaging is het vinden van het juiste materiaal: goede elektrische geleiding in combinatie met slechte warmtegeleiding. Slechte warmtegeleiding is noodzakelijk om het temperatuurverschil tussen beide kanten te handhaven. Probleem is dat de meeste materialen die goed elektriciteit geleiden, eveneens goed warmte geleiden. Warmte wordt onder andere doorgegeven door elektronen, elektriciteit ook, dus daar valt niets te winnen. Warmte wordt ook doorgegeven door trillingen (fononen). Deze trillingen probeert men op nanoschaal te dempen. Ontwikkelingen in de nanotechnologie hebben aangetoond dat het mogelijk is om de efficiency van de thermo-elektrische materialen te verbeteren. Hierdoor kan meer elektriciteit worden opgewekt dan voorheen en wordt het Seebeck effect (energy harvesting) interessant. Dit document beschrijft de eigenschappen en toepassingsmogelijkheden van thermo-elektrische materialen. Het document is opgeleverd in het project Innovatief Materialen Platform Twente (IMPT). In dit project heeft het IMPT 75 innovatieve materialen in kaart gebracht.  Met een tiental materialen is toegepast onderzoek gedaan, zodat ondernemers en ontwerpers weten of en hoe zij deze kunnen toepassen.