well-answered

I registered for a domain name before I started the exploration @MI, then it crashed down and I switched to this!!!!

I LOVE BROCCOLI so …

I think you’ll easily remember this 

WWW.HEYBROCCOLI.COM

(Repost)3D printers and what’s the difference?

Last Thursday Prof. Zhang gave me a paper that introduces a new methodology of 3D printing(Solution Mask Liquid Lithography (SMaLL) for One-Step, Multi-material 3D Printing by Material Department, UCSB).

Traditionally, the designed 3D model would be printed out layer by layer, with a single type of printing material. What I used in my school back in BHSF was like this, the PVC fiber is melted and reformed into the wanted curves when cooling; each layer coherent together before fully solidify, thus, the structural intensity depends on the programmed curing time. Because of the curing time is fixed, when under different printing conditions, the mechanic performance of the printed model varies greatly. In fact, I’ve seen one of my classmate’s design fall apart, don’t even mention how unstable the interfaces could be when trying to apply several different printing materials into a sole design.


The similar problem appears in the PuSL printing system too. PuSL system is what we have here in the lab, means project micrometer solution liquid. We use UV light to cure photosensitive polymer liquid, by control the exposing time, a thin layer of liquid on the platform cures and eventually forms the predicted figure.

Comparing to the former method, this approach has a higher resolution(um level, for the UV light) which better performs in micro scale in labs and high-tech manufacturers.  Also, this method can print any design as long as there’s a supportive structure, not only pyramidal-like the former. But fabricating process in both takes up a very long time. The resolution in each printing process is fiber’s diameter and UV light’s wavelength, in the case, which is also the unit pushing forward the upright printing process, that leads to a very slow fabricating. SMaLL can optimize both curing efficiency as well as enhance the mechanical properties. Say, there are two kinds of liquid polymers that cure when being exposed to a different light of different wavelength (in the paper was the green light, 500-560nm, and blue light, 450-480nm). When exposing to another light, the polymer material functions as a mask stays in its original condition. The method provides large depths of cure, rapid build rates and a subtle switch between printing polymer materials.

2565754824

We entered the lab today, Hongmei showed me some basic experimental operates. I’ll just put some pictures here.

About the questions, the platform and the liquid level basically works like this:

There is a structure quite pivotal to the whole instrument. A polymer film is fixed to the container, creating a 2nm gap between the film and the liquid level, which will be solidified when being exposed to the UV light. The film is important in two aspects, focusing light and press the liquid polymer to an even surface, in fact, the first few layers are printed out to create a horizontal pre-print stage for the real design. I asked where the film comes from, Hongxia said it was provided along with the machine, and the film they have at Masdar cannot meet the need. Two requirements need to be specified: the film needs to be highly transparent, as well as unlikely to stick with the curing polymer(That means being contaminated).

4084610431

Here’s an amazing discovery I just made.

The exercises I used to practice question contain at most 5-6 degrees of freedom.

To solve the problem you’ll need to either make classified discussions step by step or come up with an overall partial differential equation and give out initial and boundary conditions(or assume there is one) and 暴力解 for an analytic solution.

The former one requires a higher level of the understanding of this part of physic and a quick wit, however, the latter idea needs some preunderstanding of the knowledge, maybe some models and theories that’ll be used taught in college or graduate school.

But as I was reading some 大佬‘s blog talking about giving out solutions of a linear steady-state finite element analysis model, in her preliminary estimate she gave out a chart, with says the proposed number of degrees of freedom in a simple dynamic system was 3651!!!!!!!!!!!!!!!!!!!!!!(plus 124 inner degrees of freedom) I WAS SHOCKED as I read this and seriously! Only 5 degrees of freedom that need to be discussed in an exercise can put me in hell for 20 minutes, don’t even mention this massive scale of uncertainty! COMSOL Multiphysics software can simulate given models without knowing the relevant algorithm knowledge(although I think it’s quite necessary).

2105559045

Third day here I am still kind of overwhelmed by those things here. I am still, currently, not assigned to any specific work, to be honest, that makes me feel—really insecure…. But I think I still need time to fit myself into this kind of atmosphere…

 

Anyway

 

I went to professor Zhang’s office and(quite embarrassed because I am obviously the most know-nothing guy hanging around) asked him whether there is anything I can do. He and Hongxia were chatting and they remembered COMSOL they were talking about during the meeting this morning.

 

Right, I need to do a brief introduction to this whole thing before I continue.

 

This is the Masdar Institue of Science and Technology. MI was established in 2001 in Abu Dhabi, in collaboration with the MIT, as an independent non-profit graduate-level research university focused on advanced energy and sustainable technology. In 2017 it merged with the Khalifa University. I heard of the Masdar City many years ago before I could even imagine Abu Dhabi can be a part of my life experience. What I remembered were a huge mirror-centered solar energy gather system and a pilotless automobile, that was part of breaking news. ‘Masdar’ in Arabic, means ‘source’, researchers here are all doing projects about the source and the relevant.

I was very lucky to get to know professor Zhang and his team and work with them. I used to be part of the school’s physics Olympia team and honest to say  I am soooooo into this, but my experience in physics before was theoretic exercises and model analysis. This is the first professional lab that I seriously get in touch with(I keep saying how lucky I am to my parents all the time….it’s kind of bothering). I have had a few conversations with professor Zhang and we came up with an idea.

The focus is to use the micro 3D printing technology to design, simulate and finally print out(hope so) a cover that can reflect light in a certain range of wavelength, to protect matters that are exposed to extreme heat caused by radiation from the sun.

The idea comes from a bug in Sahara desert with a special structure of the shell that always helps it to cool down. I have explored 3D printing technology and did well in BHSF(my original school) and the professor is specialized in thermotic engineering. The lab currently has a micro 3D printer that was built by students based on a blueprint provided by MIT engineering department ( I’m so lucky because it’s a frontier technology) and a finished product made by MIT is going to be delivered to the lab this September. Here’s an idea that crossed my mind: This radiation protection project could be turned into something bigger: infrastructure or architecture that is energy efficient, energy conserved, and protect from extreme Abu Dhabi heat.

 

But before I start my thing I’ll be helping out Hongmei and her project. Back to what I was talking about earlier, Hongmei and Professor Zhang suggested that I should learn more about simulating optical physics using COMSOL and if I am interested, know more about Matlab. He said if I can do this part right not only my idea will process better but I might also be able to benefit other team members using this. I know it can be really hard but I’ve started to look up relevant materials now and if there’s any chance I’ll try to know more about this.

 

(Repost)A massive project….and thoughts

Professor Zhang then introduces me to my mentor(the way he wants to refer), Hongxia Li, a really nice BIG SIS I might be working with together later. Then I learned about her research.

Generally, as I understand, is to first simulate oil and water flux inside rocks and try to discover how to push oil out. Slice analyze the rock’s inner structure and print it out using the Micro 3D printer, classify these mini structures into types such as “throat”, “pole”, “dead-end pole”. The mini-structure is presented inside a nanotube, she connects the tube to a pressure pump and pushes 3 different fluid inside, oil, water, and a polymer material. Observation and analysis were then applied. One focus of the research is trying to change the surface property so that it could better depict the real rock.

I asked about this and Hongxia explained only the “surface ” matters so she will only need to change this parameter. Three technical methods were applied here, one, copolymerization, means combine types of polymer material together and effectively control the contact angle; two, cover the structure with a thin layer of another appropriate coating; three, which is also the most interesting one, grow some cute cute calcite crystal on top of the surface.

 

I asked why not take those min-structures into individual researches, what Hongxia said inspired me a lot. The difference between science and technology is their different emphasis because I formed this thinking pattern of always wants to know how a single parameter effect the whole thing, meanwhile forgot only when these all work together it can be applied to real industry.

323-878-8422

July the first 2018 is my first day actually getting to know professor Zhang’s lab and his team.

His personal lab is on the first floor in the research building with a bunch of expansive facilities. For his focus on studying energy science and technology, all of the equipment is more or less related to solar energy or petroleum developments.  There are two amazing things here.

 

One is an NMR_imaging thing(Nuclear Magnetic resonance), same as what the doctor uses for craniocerebral examines(brain!). If possible I really am, looking forward to seeing how to operate this thing and actually get my hands on. 🙂

AANNNNDDDD here’s the one I really like! A MICRO 3D PRINTER so cool that none of the other alike printers I’ve ever seen could ever, ever compare.

I used to be in BHSF’s 3D printer class and there were multiple kinds of such things. If I recall this right there were even a few “BOXES” that can make chocolate-ish models with cocoa powders, but also looks lame comparing to this thing here.

I designed a mini classroom using what my teacher has taught in that class. It was a very delicate and small thing and won a few prizes but what both me and my friend cannot believe was none of my school’s 3D printer can successfully print it out. I’ve asked the teacher sooooo many times and we’ve tried desperately but failed.

Maybe I could do it here HEHEHE

It’s a bit complicated to introduce how it works.

The machine we have is a prototype built by engineers and students (i was told it was built upon a blueprint designed by MIT), works by the interaction between UV light and a curable polymer. A platform supports the liquid polymer and goes downward and sideways according to need. Laser gun provides UV light and cures (solidify)the material on the top. A normal 3D printer can only hold pyramid-like structures, but this can do anything as long as there’s a supporting point.

To achieve such functions,  the optical properties of the material play an important role. The researcher controls the projecting time of the UV light so that the liquid turns to solid and absorbs just well.

I’ve got 2 Qs here,

1, when you move the platform how can you make sure the liquid level is perfectly controlled? (I think it’s harder to control than to move the laser beam)

2, how each layer of the solid polymer bonds together?