Small addition to previous post

It turns out that our image not only featured in the top images for 2013 by Nature, but was actually also used as cover for their 2013 summary.
Cheers all
http://www.nature.com/news/specials/2013-1.14378

Updates

I know, I know, it's been a long while since I last posted. I could probably launch into explanations as to why that is, but I won't.

So, a few things happened lately that require some updates. First of all, I passed my comprehensive exam and was officially accepted into candidacy for PhD. I had fun writing the written proposal since it was on the subject that I would like to research in real life if/when I get a faculty position. This last semester I also sat in a class on grant writing and it was very helpful in preparations for the comprehensive.

I also received a fellowship from the Nebraska Center for Materials and Nanoscience (NCMN), with a small press release on the subject. Always good for ego-stroking.

On with the updates!

The paper in Advanced Functional Materials finally got out in an issue (as opposed to a preliminary view). In addition, it got to be a front piece with an image designed by Joel Brehm.



The paper also received a press release from UNL, which is always nice.

Surprisingly, we got a very nice present for the end of the year, as our image was included among the images of the year by Nature. I think I will take this opportunity to post that nice image again :-)


I think that's about it for now. Hopefully, this blog will have more good news in the next year. Happy holidays to those who might happen to read this.

Cheers all

Hilarity ensues

Well, it was only a matter of time with the publicity surrounding the paper. Those who can read Russian are welcome to check out the link. The problem, of course (beyond the rather sensationalist coverage), is that I have as much to do with Russia as with ballet. I was born in Ukraine when it was still a part of USSR. I came to Israel with my parents when I was a child of 13 (USSR still existed at the time). So, any connection to Russia is, as they say, purely coincidental :-). Incidentally, it is interesting that they didn't try to claim Dr. Dzenis as having connection with Russia, though he left the USSR as an adult and has a PhD from Riga University. Then, there is the claim that I have a Masters in EE. I wish. I tried to start Masters in EE when I was in the army. Unfortunately, it didn't work out and I only took a few courses. And, finally, we are obviously not from Akron. Only Dr. Cheng who is a coauthor on the paper is. I guess these reporters at least tried to find out a bit about us (most likely found my Linked-in profile). It is more than I can say about other articles. In most cases people very obviously didn't read the paper, but only the JournalStar article or even subsequent coverage (it is like watching a children's game of "broken phone"). It is funny nonetheless.

Some explanations about the paper

Well, given the increased attention and articles about our recent paper, I decided to write a short explanation of what it actually says and the implications for those who are interested but can't read the paper behind the paywall or not interested in wading through it.

First, a short description of what was done. We used electrospinning to produce continuous fibers with diameters between ~100 nanometers and a few microns (for comparison, human hair is about 100 microns in diameter). For those unfamiliar with the process, electrospinning, similar to electrospraying, applies high voltage to a solution of polymer (you can also use a polymer melt, but it's less versatile and more complicated). Above a certain polymer concentration this process produces fibers that are deposited on a collector (in regular cases it produces a random mat and you need a special electrode to produce oriented or individual fibers). The diameter of the fibers is controlled by different process parameters and can be as low as few nanometers for some polymer systems (in our case we tested fibers as thin as ~100 nanometers).

After making the fibers we mechanically tested them. Other people previously tested such nanofibers, but usually on very short samples (several tens of microns)and the examined diameter range was much narrower. What we saw was that the fibers became much much stronger as they got thinner. This is not entirely unexpected (there are theories that predict this effect), though the magnitude of this size effect was beyond what we've expected. What was unexpected that the deformation to failure did not decrease with the increase in strength, which led to smaller fibers being able to absorb significantly more energy (expressed as toughness) than the large ones (toughness is the area under the stress/strain curve).

Now, optimally, one would have liked to examine the structure of individual nanofibers, but examining crystal structure of such small samples is rather difficult (especially for polymers). We examined crystallinity of nanofiber mats (with distribution of diameters) and found that it decreased slightly for mats with thinner average diameter. This led us to hypothesize that our increase in toughness is associated with the low and decreasing crystallinity. In order to validate the hypothesis we intentionally increased crystallinity in our fibers by heating them up. After this process, we found that the deformation the fibers were able to take before breaking decreased significantly (and thus the toughness of the fibers decreased as well). We also made an effort in the other direction (to decrease crystallinity), and found, as expected, that the toughness increased, but there were confounding effects and we decided to leave this part of the experiments for future papers.

Now, for the claims out there and for the implications of our study. As it stands, taking the fibers and using them is still a long way off. Controlling the diameter and scaling things up is not trivial. Furthermore, though the strength of our fibers is relatively high for the thinnest filaments, it is just starting to push the advanced fibers which are used in composites, armor etc. The bigger problem though is that the large toughness comes from large deformations, which is not very useful for many applications (in ballistics, for example, you are interested in the first 10% deformation and how much energy you absorb there). So, while the results are promising, it is waaay too early to talk about shirts that can stop bullets :-) The study does offer some possible paths forward. I don't want to go into too much details here, but there are possibilities to try and tailor the properties, by sacrificing some of the toughness at high deformations to get higher strength etc. In addition, the discovery that the low crystallinity might be a good thing is very unusual and goes against what people regularly do to produce advanced fibers. I hope this helps to clear some of the clutter out there. Or maybe it just confuses people who ventured here to read this post even more :-)

Cover, press release etc.

Well, it's been another good day on the professional front. Our cover of ACS Nano came out today. And the University also published a press release. I also received an Outstanding Research Assistant Award today. All in all, pretty good day.

Additions to the blog

I've added links to my recent publications and my photos selling at microstocks on the left side of the blog

Good news and more updates

Hey, it couldn't have been only a month since my last post :-) Anyway, I've had some good news recently. Despite my scepticism, Nature Materials actually agree to send our rewritten paper for review after rejecting the initial version. suffice it to say that my boss is pretty excited (maybe overly so). Nature Materials is a sub-division (if it can be called this way) of the general journal Nature. They reject about 95% of the papers they recieve at the first stage, when editors read them (which is surprisingly or not, not that different from fiction editors and agents). The rest go to peer review (I am not sure how much of those make it into print, so, I can't speculate about our chances). The paper in its new form is pretty solid in my view. I think it is better this way than the short "brevia" version we originally submitted to Science. So, anyway, I am hoping for the best, but even if it is not published in Nature Materials, it has an excellent chance of being published in another high level journal. Which brings me to another set of good news. The paper we submitted to ACS Nano had returned from review. One reviewer suggested publishing it as is, another suggeted mostly stylistic comments and one was pretty negative. some of his comments have merit and we are working on addressing them. Some of the other comments, I have to say, are slightly weird. In any case, the revision should be finished shortly and I am pretty sure it will go through this time. ACS Nano is not as high end as Nature Materials, but it is still a very high ranking journal. So, this is very good. Our third paper is almost done (finally....) and should be out to a journal in the next few days. All in all, pretty good progress. I also have some updates on the personal front, but I'll leave them for another post.

Yes, I am still alive

This turns out to be a regular feature, isn't it. I start each new post with an apology for being quiet for so long and the promise to do better in the future. So, let's just skip this part this time... The semester is finally open. I was fairly busy during the semester and the couple of weeks after it ended. Now, finally, things had calmed down a bit. We've finally submitted one paper. To Science of all places. They didn't kick us out yet (though it is surprising they hadn't replied yet after more than three weeks. For those who don't know, Science and Nature have a two tier acceptance process. Most of the papers are rejected without peer review by the editor. This usually takes about a week. In case the editor decides the paper has potential, it is sent out to reviewers, but they usually let you know if this happens. So, the fact that we hadn't heard anything is fairly strange). I am fairly skeptical about our chances. My boss decided to try and go with a very specific short format, which is published one per issue. This makes it next to impossible to get through. Before sending it out to the journal, he sent the paper to few specialists in the field to see what they say. Most responses were very positive, but one of the guys warned us that it would be very hard to publish in this format. Anyway, even if the paper is eventually rejected, together with the supplementary material, we have a full paper to send to any other journal. Two more paper drafts were sent to our collaborators at Northwestern. These are fairly straightforward papers, which have good chances of being published in high level journals. I am guessing, they'll be out to journals fairly soon. We are also working on another paper, which should be done shortly. Now, you can understand why I was so busy lately :-) On the home front nothing changed much. I finished a draft divorce agreement with my lawyer and sent it to my ex. No response as of yet. In the meanwhile, she took the kids for a month of vacation in Israel. I would have loved to go, but ,unfortunately, couldn't. They've been gone for less than a week, and I already miss them. I have no idea how what things will be like when they move to North Carolina in August... Well, that's it for now. I will try to give more updates, but no promises :-)

Free at Last

Hooray! This semester is finally over. I sent the last of my assignments in on Friday (had the kids over for the weekend). This was one crazy semester. The class of my boss was interesting, but the pace and the sheer amount of info to digest together with the other things, such as learning to program in Matlab (I knew I had to do it earlier :) ) made the course very time intensive. The other class I took was relatively easy, but also time intensive due to a great number of labs and home assignments. Together with the important project review, the papers and the personal stuff, this semester was very very hard on me. Now, it is finally over. Here is hoping the next one will be better :). I am off to New York with my kids next week to visit my cousin.
Happy holidays to those who might be reading.
Cheers

Tiger Lily RIP

I received some bad news a couple of days ago. When we left Israel to come to US, we left one of our cats, Tiger Lily, with my wife's parents. Unfortunately, she passed away a few weeks ago (just before my wife's mom came here). Tiger Lily wasn't young, but she wasn't too old either (she was 12). She always suffered from overweight and eventually died of liver problems. She was a very nice and friendly cat, and she will be missed. I will post some pictures later.

Through the Rabbit Hole

I haven't posted on personal issues on this blog, but there some important things that I think I should share. It has been building up for a while now. Bear with me. If anybody is reading this, but doesn't feel like reading about my personal problems, skip this post.

About a month ago I and my wife decided to separate. Our marriage was in trouble for a long time before that (for about year), so this decision didn't come out of the blue. In the past several weeks, I reflected on the last year and realized just how unhappy I was. While we are on ok terms at the moment, and would do everything we can to ease the situation for our kids, too much bitterness had accumulated and is poisoning almost every interaction we have. At the moment, the situation can't be helped. In fact, our relationship had improved slightly after we decided to separate. I guess, to a degree we both feel relieved, and are trying to move forward (I certainly do). It isn't easy, and will certainly have an impact on our kids, but, in the end, I think it will be for the best. This way we both can get on with our lives (we are still young). Only time will tell.

Over the last couple of weeks, I had a friend, who is in a somewhat similar situation, help me through. I found that I can still interact with people, and that was a major thing. I am deeply grateful to her for all the help, and I am also trying to help her through her rough times. It's strange. I always thought myself as self-sufficient -- basically not needing anyone, but she showed me just how much I missed that human component. I hope it will make me a better person in the long run, as I begin this new stage in my life. I just realized something this morning. I've become a true Israeli. For those who don't know, Israelis who are born in Israel call themselves "tzabarim". Tzabar is a fruit from a cactus. It is tough and has needles on the outside, but soft inside. :)

As Danny in the Song of Ice and Fire keeps saying, "If I turn back I am lost." I don't regret my life so far. It had many good moments and gave me two beautiful children, but it is time to look ahead.