My Time in Luxembourg and at the META19 Conference in Lisbon

This is an update from my recent travel to Luxembourg and Lisbon. I had the privilege of traveling to Luxembourg to deliver an invited talk to my collaborator's group; we have published 2 papers together, are about to have a third published (for which I'll write a post once the publication is official), and are working on a fourth. It was productive to meet with my collaborators to hash out the details of our fourth paper together, and I think I did reasonably well delivering my talk, for which the first part was about the work with my collaborators modeling fluctuational electromagnetic phenomena at the interface between small objects that have to be treated at the atomic scale and large objects that can be treated as continuous, and the second part was about my more recent work purely within my group putting upper bounds on thermal radiation and heat transfer. Additionally, I appreciated the interesting conversations I had after my talk with various members of that group.

I also got to go to the META19 Conference in Lisbon, which is centered around research in nanophotonics and metamaterials; there, I presented an invited talk about the aforementioned work on upper bounds to heat transfer, which my advisor graciously let me do in his place. It was great to meet people that I knew associated with my advisor but hadn't seen in a few years, and we got to discuss each other's work in great depth; I got to also meet a few other people for the first time, and had some good conversations with them about our respective projects too. That said, while I think the delivery of my presentation there was good, I did feel like I could have done a better job of preparing my presentation in a way that better fit the context: my presentation may have been too theoretical, so for an audience of engineers who care more about using metamaterials and nanophotonic architectures to make new devices, I could have been clearer about broad physical insights and done a better job connecting the findings in my work to ideas of interest to such researchers. Additionally, I could have probably done a better job networking, though my reticence was in part due to uncertainty on my part regarding my future plans.

I also had a day in each city to explore, but there were issues in each case. For one, neither Luxembourg nor Lisbon are especially tourist-oriented cities compared to places like London, Paris, Madrid, Barcelona, or Berlin, as far as I've heard: both cities have a lot of nice restaurants and cafes as well as many nice viewpoints and other areas to simply hang out and relax, but there aren't so many specific attractions, as Luxembourg is known more for housing EU governmental offices as well as international finance companies, while Lisbon seems to generally not have invested in tourism as much. I did hear in each place that the surrounding countrysides are beautiful, so perhaps that is where more tourism happens and where more interesting things can be seen. (Also, it didn't help that I was in Lisbon on a Monday, when many things are closed.) For another, both cities are not especially good for people like me in power wheelchairs who want to travel independently; people who are able-bodied, in manual wheelchairs, or have disabilities that require them to be assisted by partners or personal care attendants full-time may be better served. In Luxembourg, I didn't feel like I missed too much because it's a fairly small city anyway, and the public transit buses were accessible (though there were some issues even there). In Lisbon, I felt like I missed more because it is a bigger city, yet its Metro rapid transit train system, which is supposedly accessible, actually has large gaps between the train floors and platforms, and most of the buildings have large steps to enter. I do hope to visit Europe again, but when I do, I hope to make sure it will be a city/area that is more friendly to people in power wheelchairs.

My Time at the 2019 APS March Meeting

This is a quick update from my trip to the 2019 APS March Meeting in Boston, Massachusetts at the beginning of March. I felt like my time overall was somewhat mixed, though positive on balance. On the negative side, my talk was lumped into a totally unrelated session on a Thursday afternoon, in which the talks weren't of interest to me and were generally not so well-delivered, the audience consisted almost entirely of the speakers who left after their own talks (and that included me after I saw what was happening, though I was grateful that some of my friends came for my talk), and the first talk which was supposed to be a 36 minute-long invited talk was canceled in the absence of the speaker, leading to a break during that time. Additionally, my advisor and I were busy preparing a paper unrelated to the work I would be presenting, and I've also been taking my time to figure out what I want to do after graduation, so I didn't prepare a schedule of talks to attend as well as I had in the previous two years. That said, on the positive side, I paced myself properly in attending talks, and I did appreciate having conversations with people from my department as well as people I knew in college about our work as well as future plans. I also had a lot of fun hanging out with friends from college as well as graduate school, and though I could have done a better job networking, I did try to reach out as much as I could. Finally, I had a great time skipping the last day of the conference and visiting MIT instead, where I got to catch up with professors from the physics department as well as other people whom I knew well in college (and met some people for the first time too); I felt like that was a far more useful & productive move. Next year, I hope to be able to present in a session more relevant to my current research interests, and to do a better job of tailoring my networking and session attendance to my future interests (which I hope will have solidified by then).

My Time at the 2018 APS March Meeting

This is a quick update from my trip to the 2018 APS March Meeting in Los Angeles, California at the beginning of March. I felt like I learned many lessons from my trip to the 2017 APS March Meeting and was able to apply them here. Chief among them, I realized that a large part of this conference is networking, whether that involves the formation of new relationships or the maintenance of old ones, so I got to enjoy myself more in meeting with old friends and collaborators and making some new connections as well; that also meant that I focused more on going to talks of immediate relevance to my research interests as well as my friends' talks to show them support, and I didn't worry about trying to fill each day by attending talks and sessions like I did last year. I was able to present my work this time too: I presented a model for vibrational contributions to radiative heat transfer and van der Waals interactions among molecules, along with interesting results in specific systems. This was in a session that included people from both the microscopic van der Waals and macroscopic Casimir communities, and while I was the only one who discussed heat transfer per se, I did get to see a nice mixture of the two communities, and some interesting discussions did come out of that. Overall, I had a great time, but I do think that as I progress further in my graduate research career, it may be good to not only continue to attend the APS March Meeting in the future but look into more specialized conferences too.

Skepticism in My Photonics UROP

I've mentioned here on several occasions that I've been doing a UROP regarding nanophotonics/photonic crystals. Specifically, my first project was in determining whether particular types of photonic structures might enhance absorptivity of light, which would help solar cells that convert that light into electricity. The goal is that the absorptivity enhancement (versus no texturing over the solar cell) should be over as broad of a frequency band as possible, because it is difficult to manufacture many different kinds of photonic structures just to satisfy performance demands over many narrow frequency bands. I worked on this project for about 4 months, because that was the time that my postdoctoral UROP supervisor was around (he moved after that). I was able to get some really nice-looking results in that time, and I figured there wasn't much more I needed to do to wrap it up, so I felt comfortable generally moving on to a new project (which I have been working on since 2012 February or so). The enhancement results looked great compared to existing designs, so I thought we might be on to something here. Recently, things started gearing up for a publication submission.

Today, it all came crashing down. Why? Another postdoctoral UROP supervisor (who I have worked with since last year primarily on my more current project but recently joined in to help progress of the older project, which is the subject of this post) asked me some hard questions about what I was really doing. Because of this, I realized that one of the parameter choices in my calculations that were giving such nice results was fatally flawed. When I fixed that issue, the results I was getting suddenly looked significantly less compelling; with that, any dreams of publication were dashed.

Why did this happen? It boils down to me not being skeptical enough about what was going on. A large part of this has to do with the fact that because this was my first UROP, I didn't have a great idea of what was going on in terms of details. And because that time I spent was only about 4 months and was followed immediately by a new project, I didn't spend much more time on that project after that. Ultimately I got complacent in more ways than one. Because the code I was using was based on existing code for similar calculations, I figured it must have been written to work even with the modifications I was making. I also figured that because I had been getting consistently good results from what I had done over those 4 months, I just needed to worry about those results on the surface and not the fundamentals operation of the code. Those two assumptions combined such that even though I had seen the results of not being careful in my second UROP project and had become much more careful about checking that code as a result, I didn't think I needed to apply the same level of care in checking the code used for the first project.

After realizing the implications of this, I did a few more calculations in a significantly more mopey mood. But then I thought about this and I realize that I shouldn't feel so bad about this. Why is that? Here are a few reasons in no particular order.

1. I've made similar mistakes before, and I've really come to learn from them. One example of something that I thought was going great but turned out badly has to do with email. People who know me may have heard this story, and people who have known me for a while may have actually been there to see me do this, but I won't share the story now; I believe it is sufficient to say that I am now a lot more careful when sending emails especially to large groups of people. A reverse example actually comes from my second UROP project: for a while I was making a mistake in my code that was giving garbage, but after many months of trying various fixes, one particular fix solved all the other issues. Since then I have been a lot more careful about checking my code for that project (though I guess I was confident enough about the code used in the first project that I thought such a high level of care might be unnecessary).

2. I didn't think I would be in the position of having my work for both projects on paper until very recently. Now I can go back to thinking that in any case my second project work would be more likely to go on paper (especially as I know that I have taken a lot more care in checking my code for that project).

3. Several months ago, when my second project was stalling, I was asking myself why it wasn't going as smoothly or quickly as my first project. Now I know that the first project should have in fact gone as slowly as the second project for the work to become as solid and carefully checked. The other part of this issue is that I have been working on the second project continuously, so I have been able to make continuous adjustments to the code and work progressively higher levels of care in checking the code in a smooth manner. Because I essentially stopped working on the first project after those first four months, if I adopt more careful code-checking now, it'll feel more like I'm starting over from scratch, which makes the process feel a lot more frustrating.

4. With all this, I feel like I have already learned a lot more from this lesson than I would have if everything was fine and dandy and this work did get submitted for publication.

5. If nothing else, I hold out hope that I may be able to salvage some good results with the fixes I have made to the code of the first project.

There are two morals to this story. The first is that I shouldn't just check the code I run; I should check it in an actively skeptical manner, always questioning each and every line. The second is that C++ is way more painful to read and (to a lesser extent) write than Scheme is for the kinds of calculations I run.

More on My Photonic Crystal UROP

In my post at the end of the summer, I talked a bit about what I actually did in that UROP. Upon rereading it, I have come to realize that it is a little jumbled and technical. I'd like to basically rephrase it in less technical terms, along with providing more context on what I did in the 2011 fall semester. Follow the jump to see more.

Long-Term Review: Because Now I Can

I am doing a UROP on campus this summer (as opposed to last summer, when I interned at NIST), and it is a continuation of my UROP from the last two semesters concerning photonic crystals. This summer, my ultimate goal is to be able to use MEEP finite-difference method simulations to recreate the spontaneous emission spectrum of a particular photonic crystal structure of great interest to the research group in which I am working.

To do that, I create the simulations as programs written in the Scheme programming language (a derivative of Lisp) and executed through MEEP. These actual steps are done on a cluster of computers, so the laptop computer that I have been using at my office is merely a terminal for the cluster. Because that laptop runs Microsoft Windows XP, there is no built-in way to SSH into the cluster, so I have to use a UNIX-like terminal emulator for Microsoft Windows; in my case, I use SecureCRT combined with XWin32 for graphical programs like Gedit and Geeqie. Unfortunately, that laptop is at least 7 years old (judging from its hardware specifications and thickness), and with Microsoft Windows XP, it is certainly showing its age; last semester it worked just fine, but a few days ago, it started choking trying to run Mozilla Firefox/Adobe Reader, LibreOffice Calc, and SecureCRT simultaneously. I asked my UROP faculty advisor if I could use a much newer desktop in the office that I use that no one else seems to be using, and he was fine with that; I even asked him if I could run Linux on it, and given that my previous UROP postdoc advisor (in the same research group) ran Ubuntu and helped other people set up Linux for work computers, he was fine with that too.

This presents a unique opportunity for me this summer with regard to this blog, and that's where the title comes in. One of the most common complaints about the reviews I do here is that they use the live session without trying the installation on real hardware at all. Also, because I usually only test the live session, the actual amount of time I spend is not more than a few hours spread over two days or so. Now, I have finally secured the official go-ahead to do with the computer whatever I feel is useful, so I will attempt to take more time to test some distributions (now as an installed session on real hardware) that I have said before that I would have no problem installing, because I want to see just how true of a statement that is. The computer in question is probably not more than 3 years old; it is a Dell desktop with a 64-bit Intel Core i5 processor, 4 GB of RAM, a 320 GB hard drive, and an ATI graphics card (though I am not sure if the graphics card is integrated or dedicated).

Given the amount of time I have left this summer to work, I intend to test each distribution for between 7-10 days of work, though that may change depending on my schedule and if a given distribution really does not work out. I have already installed Chakra 2012.05 "Archimedes", so that will be the subject of the first real "Long-Term Review" post. Each of these posts will be updated with a daily label detailing any changes, bugs, or other things that I notice. Each post will also have a "Day 0" label at the top sort of revisiting the live session like I normally do to set up my ideal desktop once more. At the end of the testing session (again, 7-10 days), I will publish the full post. While the "Day 0" section will basically be like a full review all over again, the following days' sections will be shorter. It doesn't take a long time to see if my favorite applications work or not, but it does take longer to really feel comfortable with the desktop, look for bugs and quirks, and make sure that upgrades go smoothly. So in these posts, I will really be looking out for details like how well the file manager and panel do stuff that I want them to do on a daily basis, how stable the system is, et cetera, as opposed to simply seeing once if something like Skype works; at my UROP, I only really need a web browser to see some web pages and check email, a PDF viewer to read papers, and a terminal emulator to SSH into the cluster, so I could theoretically settle for something like Ubuntu, but I don't want to waste this opportunity.

Again, I have already started with Chakra. I've always been fond of #!, so I might give that a go too. I'll also give Sabayon a run given that version 9 seemed to work so incredibly well. All of these will be the 64-bit editions because the computer has a 64-bit processor and 4 GB of RAM, so I want to make use of that. That leaves room for a fourth distribution (but probably not more than that); I will have to think about what I want to save for last, and I certainly welcome any comments and suggestions on the matter. Do look out for these posts along with my usual reviews and other random posts.

(UPDATE: Duh. I just realized I could do a long-term test of a prerelease version of SolusOS at the end of summer, and that would be the fourth distribution to test. Hopefully by then a 64-bit beta edition will have been released. I haven't written about it formally, but I have checked out SolusOS 2 Alpha 4, and I'm quite pleased with what I see, especially for an alpha release. Now, I will be able to see if that is really true over a longer period of use on an installed system instead of just a shorter period of use on a live system.)

First UROP: Thermophotovoltaics

I apologize for not having posted anything in a while. For one, I've already become quite busy, so I haven't had much time to do stuff like this. For another, I have been (and still am, as of now) sick for over a week, so I've just been trying to rest whenever I can.
This week, though, I started my first UROP! Yay! It regards modeling new thermophotovoltaics (thermal solar cells) that use photonic crystals. Photonics are to light what electronics are to electrons, so the idea is that photonic crystals will give enough fine-grained control over photons to make capturing more parts of incoming solar radiation even easier and more efficient; this will of course increase the overall efficiency of solar cells too. Right now, photonic crystals have a lot of room for improvement, and ceramic-metal composites called cermets are currently the best at selectively absorbing different wavelengths of solar radiation, but the idea is that with time and many improvements, photonic crystals will be the way to go.
Currently, I'm just reading up on the basics of photonic crystals, but I can't wait to begin working on a topic and in a group that have both been recently featured in Slashdot, and which will probably have a pretty big impact on renewable energy sources!