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A blog about rheology
Andrew Sun
15 posts
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- March 25, 2011
- 03:34 AM
- 785 views
Gap dependent rheology on rotational rheometers
by Andrew Sun in On The Road
Grenard, V., Taberlet, N., & Manneville, S. (2011). Shear-induced structuration of confined carbon black gels: steady-state features of vorticity-aligned flocs Soft Matter DOI: 10.1039/C0SM01515F Conventional rotational rheometers allow test procedures of varying shear strain/stress, temperature and time, corresponding to multiple … Continue reading →... Read more »
Grenard, V., Taberlet, N., & Manneville, S. (2011) Shear-induced structuration of confined carbon black gels: steady-state features of vorticity-aligned flocs. Soft Matter. DOI: 10.1039/C0SM01515F
- January 5, 2011
- 07:21 PM
- 627 views
Rheology within the concept of aether
by Andrew Sun in On The Road
N/A (1886). Dilatancy Nature, 33 (853), 429-430 DOI: 10.1038/033429b0 I encountered the word “ether” which apparently did not mean the organic reagent when I was reading a short comment on O. Reynolds’s lecture on dilatancy published on Nature in 1886. … Continue reading →... Read more »
N/A. (1886) Dilatancy. Nature, 33(853), 429-430. DOI: 10.1038/033429b0
- November 5, 2010
- 12:53 PM
- 705 views
Tired of “novel supramolecular hydrogels”
by Andrew Sun in On The Road
Zhang, X., Huang, J., Chang, P., Li, J., Chen, Y., Wang, D., Yu, J., & Chen, J. (2010). Structure and properties of polysaccharide nanocrystal-doped supramolecular hydrogels based on Cyclodextrin inclusion Polymer, 51 (19), 4398-4407 DOI: 10.1016/j.polymer.2010.07.025 Last year I unsubscribed … Continue reading →... Read more »
Zhang, X., Huang, J., Chang, P., Li, J., Chen, Y., Wang, D., Yu, J., & Chen, J. (2010) Structure and properties of polysaccharide nanocrystal-doped supramolecular hydrogels based on Cyclodextrin inclusion. Polymer, 51(19), 4398-4407. DOI: 10.1016/j.polymer.2010.07.025
- October 12, 2010
- 03:13 PM
- 849 views
The kind of experimentalist I like
by Andrew Sun in On The Road
Boukany, P., Hemminger, O., Wang, S., & Lee, L. (2010). Molecular Imaging of Slip in Entangled DNA Solution Physical Review Letters, 105 (2) DOI: 10.1103/PhysRevLett.105.027802 About the paper Prof. Shiqing Wang (王十庆) have long been interested in observing the event … Continue reading →... Read more »
Boukany, P., Hemminger, O., Wang, S., & Lee, L. (2010) Molecular Imaging of Slip in Entangled DNA Solution. Physical Review Letters, 105(2). DOI: 10.1103/PhysRevLett.105.027802
- March 13, 2010
- 04:16 PM
- 811 views
The most hated journal in science?
by Andrew Sun in On The Road
Enserink, M. (2010). Elsevier to Editor: Change Controversial Journal or Resign Science, 327 (5971), 1316-1316 DOI: 10.1126/science.327.5971.1316A non-peer-reviewed journal called Medical Hypotheses is facing possibly its end as reported by Science, because it contains science related contents that are not...... Read more »
Enserink, M. (2010) Elsevier to Editor: Change Controversial Journal or Resign. Science, 327(5971), 1316-1316. DOI: 10.1126/science.327.5971.1316
- March 7, 2010
- 03:28 PM
- 760 views
Are they scientists?
by Andrew Sun in On The Road
This is not a rheology post (yet).The recent Nature editorial:Editorial (2010). Do scientists really need a PhD? Nature, 464 (7285), 7-7 DOI: 10.1038/464007a caught Chinese readers eyes slightly more than usual, because it mentioned in detail a China based commercial...... Read more »
Editorial. (2010) Do scientists really need a PhD?. Nature, 464(7285), 7-7. DOI: 10.1038/464007a
- August 10, 2009
- 04:19 PM
- 922 views
Research is gray without industrial stories
by Andrew Sun in On The Road
Polymer science is more unique in its physics rather than chemistry. All reactions in various polymerization known today are not unconceivable in the scheme of organic synthesis. There is no new concept in reaction mechanisms. In contrast, the unique properties of polymer materials mainly stem from chain topology rather than detailed chemical structures, which have led the polymer physics research from Flory’s mean-field theory, in a statistical physical scheme, to de Gennes’s scaling theory, in a fractal and non-equilibrium physical scheme. This strand of study have long been stimulating the synthetic effort for precise, monodispersed model polymers for experiment, because most theories that are mathematically tractable assume a monodispersity presumption.
However, stories from the industrial world may be a little different. Broader molecular weight distribution, for example, is favorable in rubber processing, for the resulting plasticizing effect from the lower molecular weight portion. Branched structures are also desired in many cases of polyolefin applications, i.e. blends. In some rarer cases, unknown additives during processing can affect the product properties so significantly that alternative routes assumed to result in the same product would mysterious give a very different product in fact. In the theoretical aspect, empirical equations, derived by phenomenological methods, are also more favored by engineers, although most of these equations have little to no physical meaning. The above mentioned differences between industrial and academic studies constitute a large part of the reasons for the depletion of the two fields. And researchers in the former fields may know much less about the latter than they should be, while not necessarily vise versa.
In the latest issue of Science, a special one of industrial chemistry, Phillip Hustad told a colorful story1 about how industrial research effort, under additional constraint of cost or price, give rise to new commercial polyolefins which continue the legend of polymeric material after a century of development. The article is also thought-provoking for academic research, trying to inform us a long-been-neglected origin of innovation.
The article mainly focus in one ongoing innovative process in the industry, namely Olefin Block Copolymers (OBCs), describing why early research failed when commercial consideration comes in, and highlighting the ideas that lead to recent commercial success. It is an amazing story. But more invaluable of this article are some in-depth words by the author that really tell some truth:
[T]he development of polymeric materials is much more challenging when practical constraints are imposed and success is defined by commercial viability. It is often the case that overcoming one obstacle simply leads to another, but useful innovations can stem from explorations of these perceived contradictions…It is common sentiment that “precise” and “useful” are directly correlated in polymeric materials. This may be tru for many applications, but the required level of precision ultimately depends on the material’s desired function. With biological systems, a single mistake can have drastic consequences, but in simpler polymeric materials, the penalties for imperfections are far less grave.
However, knowing now the difference in results between academic and industrial research, it is still impossible and unnecessary trying to extend the academic kind of research wisely and replace the industrial labs, because of their different in motives.
Industrial and academic R&D differ in a number of ways, most notably the motivation behind them…The difference between the two missions is evident in the way success is measured. In industry, success comes with commercial sales of the material, but in academia, success is measured by winning grants and publication of results in high-quality peer-reviewed journals. The academic researcher is less constrained with respect to practicality, scalability, or final product price; creativity is the bottom line. The industrial researcher, on the other hand, knows that even the most creative scientific breakthrough must ultimately lead to a commercially viable product for the company to realize an economic benefit.
Between lines, this comparison implies that the trait of academic research has been determined by the whole system, the journals, the publish-or-perish rule, and the peer reviewers — ourselves. Industrial labs have less pressure to publish, which allow the researchers with time and patience to identify and solve real world problems. Possibly the detached of academic research from the real world and ordinary life also causes the misunderstanding of scientists among the public. Most modern products which ordinary people enjoy have distant and vague relation to the ongoing research of pure science, while the creativity of academic researchers reported by various press releases is just “useless”, if not “dangerous”. In addition to strenuously explaining the relationship between the cutting-edge scientific breakthrough and the ordinary life for the public, as some scientists and science writers have been trying to do, maybe the research system itself should also consider a change that includes more real world problems, which makes the impact of research more obvious both for peer-review journals and for the mass.
fn.1 Hustad, P. (2009). Frontiers in Olefin Polymerization: Reinventing the World’s Most Common Synthetic Polymers Science, 325 (5941), 704-707 DOI: 10.1126/science.1174927
... Read more »
Hustad, P. (2009) Frontiers in Olefin Polymerization: Reinventing the World's Most Common Synthetic Polymers. Science, 325(5941), 704-707. DOI: 10.1126/science.1174927
- August 6, 2009
- 09:29 PM
- 769 views
Digital age or mass production age?
by Andrew Sun in On The Road
The editorial in the July 24 issue of Science1 informed me with a report by the Nanional Academies of the US, Ensuring the Integrity, Accessibility, and Stewardship of Research Data in the Digital Age. I can obtain full text of the report for free because I’m a reader from developing country. But I only had time to read the summary section.
The report gives several recommendations to different roles in the modern scientific infrastructure. Two main ideas shared by these recommendations is that to use digital technology to fight digital frauds, and that higher transparency of both the research and peer review process is needed. However, the recommendations also show a layered strategy to fight digital frauds, from individual researchers, institutes to journals and stakeholders. Whereas indeed no single layer of effort can stop the scientific frauds once and for all, neither can the sum of them cover up the whole process, because these layers only represent the “production” part in the industry of science research. In the “mass production” age of science research, to discover with only occasional defective products cannot be successful without the help of “consumers’” feedback, which means the whole groupof readers of the research report. The wholeness should be most ensured because we are talking about very rare cases which may affect a small number of people. We are less probable to discover them if we only receive part of the report from the consumers.
The current assembly line from researchers to journals is quite perfect already, in ensuring a high percentage of qualified product of research. To discover still very rare cases of frauds, two or three reviewers invited by a journal and before publication is obviously ineffective and insufficient. The idea of “using digital technology to fight digital frauds”, or better put, "using IT (Information Technologies) to fight IF (Information Frauds, and also, maybe cleverer, Impact Factor), applies here. To break the space limit of printed journals so that all rather then essential research data are avaialable to the public rather than the subscribers, we have to embrace the Internet which provides us with unlimited storage space, and also allow for real open access. We also need to encourage the role of Web 2.0 activities like blogs and social network the accelerate the discovery of occasional faults and frauds in the ocean of published papers.
The recently response in the blogosphere to the JACS paper which describe the oxidative property of NaH best exemplified the above idea, although in this specific case there need not be a scientific frauds.
1 Kleppner, D., & Sharp, P. (2009). Research Data in the Digital Age Science, 325 (5939), 368-368 DOI: 10.1126/science.1178927
... Read more »
Kleppner, D., & Sharp, P. (2009) Research Data in the Digital Age. Science, 325(5939), 368-368. DOI: 10.1126/science.1178927
- August 4, 2009
- 11:41 AM
- 984 views
No one added their test on oxidative NaH to ResearchBlogging.org?
by Andrew Sun in On The Road
I have been busy setting up the Chinese language version of ResearchBlogging.org. To explain how research blogging can be meaningful and important to the Chinese bloggers I have to provide several points and examples in an introductory webpage.
One of the best example is the recent blogging review on a NaH catalyzed oxidation reaction published on JACS1. The unexpected property of this reagent stirred up a number of synthetic chemists who repeated it and reported on their blogs. Chemistry World even reported this reviewing action from the blogosphere. This event best exemplified the role blogs can play in the “post-peer review” process — peer review on a published research work, during especially controversies in the academic community.
If ResearchBlogging.org — a Web 2.0 tool to syndicate research blog posts into tagged, searchable, RSS-feeding, and DOI-linked network — has gained supports from major chemistry blogs, this oxidative NaH events must have some records in it. However, I did a search in ResearchBlogging.org for that JACS paper but no blog post was related. Blogs I know which wrote about this paper — Totally Synthetic, Carbon Based Curiosities and PeterMR’s blog did not use ResearchBlogging.org to spread the discussion. My post here may be the first on ResearchBlogging.org linked with the controversial JACS paper.
These blogs may not need to use ResearchBlogging.org since they have had enough visits and comments as were shown under their posts. Indeed, they, not and well without ResearchBlogging.org, led and accelerated this discussion. However, ResearchBlogging.org and its readers may lose an opportunity to join this discussion. After all, Web 2.0 is about the effect of collective behavior of unknown contributors, instead of led, concentrated effect by several famous individuals. Though the latter may still be important, but more interesting is the former, which ResearchBlogging.org seeks to promote.
As a blogger you may care no other’s view and be as independent as possible among the WWW, but as a researcher you have to be the opposite, and only in this case ResearchBlogging.org can be helpful and attractive to you.
1 Wang, X., Zhang, B., & Wang, D. (2009). Reductive and Transition-Metal-Free: Oxidation of Secondary Alcohols by Sodium Hydride Journal of the American Chemical Society DOI: 10.1021/ja904224y
... Read more »
Wang, X., Zhang, B., & Wang, D. (2009) Reductive and Transition-Metal-Free: Oxidation of Secondary Alcohols by Sodium Hydride. Journal of the American Chemical Society, 2147483647. DOI: 10.1021/ja904224y
- March 7, 2009
- 04:00 AM
- 1,118 views
Is science a must for human being?
by Andrew Sun in On The Road
A Thesis published on Nature Nanotechnology1 shown that public acceptance of nanotechnology, and also generally any new technologies, depend not on the knowledgeablility of those technologies but former religious status of the public.
Strength of religious beliefs is negatively related to support for funding of nanotechnology. Religious apprehensions that developed earlier, in response to biotechnology, served as a template for reactions to nanotechnology. People for whom religion was not very important were more supportive of funding for nanotechnology. Once more, knowledge of nanotechnology had little influence.
Originally, science and religion work separately on human’s spiritual world and do not conflict. The reason why they conflict in the real world seems to be that scientists need to get funding from the public, where science and religion must interact. So scientific research is not a purely personal hobby today, it depends on the taxpayers and therefore is part of the governmental motivation. So why does a government need science? Because nations in the modern time have realized the importance of science and technology to the economical, military and political power, right? That’s why science exist.
But I never hear that religion, or the religious loyalty of its people, plays a role in a nation’s power. Religion still exists only because we humans are born to be religious. Religion exists as long as human beings exist.
So how about science?
Einstein had the following paragraph in his letters:
The development of Western science has been based on two great achievements，the invention of the formal logical system (in Euclidean geometry) by the Greek philosophers，and the discovery of the possibility of finding out causal relationships by systematic experiment (at the Renaissance). In my opinion one need not be astonished that the Chinese sages did not make these steps. The astonishing thing is that these discoveries were made at all.
So, as I agree with, at least Chinese sages did not make these steps. So we are not born to have these two capabilities science bases on. So science does not exists as long as human beings exist.
What do you think?
1 Chris Toumey (2009). Hearts and minds and nanotechnology Nature Nanotechnology, 4 (3), 136-137 DOI: 10.1038/nnano.2009.16... Read more »
Chris Toumey. (2009) Hearts and minds and nanotechnology. Nature Nanotechnology, 4(3), 136-137. DOI: 10.1038/nnano.2009.16
- February 24, 2009
- 08:30 PM
- 1,409 views
Please provide me with more information
by Andrew Sun in On The Road
First things first, I believe that it’s normal and should be highly appreciated that criticism becomes the major voices from the west as China starts to get into their eyes. This will not last long, and this is why the nation should appreciate them more. But it seems quite not the case, critiques are much less than what I have expected, and China still have been incapable to pay enough attention and consideration to the critiques that have come out. For individuals like me, they have freedom to form their own points, based on “facts” they can collect from news. Sometimes however, it is the lack of factual information that set us into confusion.
In the Feb. 19 issue of Nature is this editorial titled Collective responsibilities1, which provided invaluable opinions that can surely help China overcome its hurdle toward scientific independence. But it mentioned something I failed to find more information of:
The spread in China of unproven stem-cell therapies for conditions such as epilepsy and spinal cord injuries has left the nation’s health authorities concerned.
and,
The Chinese authorities, however, tend to have an aversion to congregations— especially those such as the Falun Gong, which they believe pose a threat to the country’s stability. So the Ministry of Civil Affairs keeps a tight hold on who is allowed to organize in any formal sense. As a result, China’s stem-cell hopefuls must go through the slow process of planning and applying to become a ‘level 2’ society.
According to my knowledge of English, the as a result implies a causal relationship.
So are there some scandals about the Chinese authority’s misconducts on the stem cell research community? Is there a Chinese stem cell organization once being pressed down by the Ministry of Civil Affairs? This is ironical that I who live in China have to ask people who are not about whether something did happened in China. But I assume you understand this. I have already tried Google.com, but with no success. So I am asking you to provide me more information about this issue. If you ever heard of such kind of news, please tell me. You can just tell me “yes there seem to be once when I heard that … but I forget the detail”…
Or, this is a piece of news that first comes out from an Editorial article, which I believe is not appropriate. Editorial should not serve for news breaking itself.
1 Nature (2009). Collective responsibilities Nature, 457 (7232), 935-935 DOI: 10.1038/457935a... Read more »
Nature. (2009) Collective responsibilities. Nature, 457(7232), 935-935. DOI: 10.1038/457935a
- February 23, 2009
- 03:10 PM
- 1,213 views
Latest report of adaptive synthetic surfaces
by Andrew Sun in On The Road
A dung beetle’s never too dirty. From Wikipedia.org
The biological concept of adaptation has sneaked into synthetic materials research. I was informed of this by a report on Adv. Mater.1 describing an adaptive non-adhesive surface. The report cited further for us a review on Prog. Polym. Sci.2 summing up the advances in fabricating smart surfaces by designing and synthesizing polymer brushes.
Yes. We have got encouraging advances in synthetic and fabricating skills, as evidenced by numerous reports on delicate yet strange structures on every issues of high impact chemistry journals, without, however, knowing the practical uses of them.
And ‘chemistry that really works’ cannot be easily achieved by conceiving such exciting concepts as ‘an adapting non-living thing’, ‘a smart nonintellectual being’, etc. In the particular case of non-adhesive surface, which we wish can be equally non-adhesive both in air and in water solutions, as the report on Adv. Mater. has excellently reviewed, even the smartest, most adaptive design by human failed. Adaptive surfaces for this purpose has been tried to achieved by grating amphiphilic polymers so that, the hydrophobic segments swell when placed in air, while the hydrophilic segments swell when place in aqueous solution, both cases being unfavorable for adhesion. However, the real products are not smart enough, they adapt too slow due to the slow motion of polymer chains. Softening the polymer surface make the surface sticky too due to increased contact area, which is favorable to adhesion.
When confronting such difficulties, we often turn to biomimetics too late. Soil animals which survive in varying humidity in soils have their solution to prevent soil adhesion on their skins, which are commonly a triple combination of cuticles with different smooth appearances, liquid secretion, and electrical charges. Although like in most cases, the structure-function relationship here is complex, we can well be satisfied by merely clumsy mimicking of its mechanism. Close-packed monodispersed silica nanpoarticles as the artistic ‘cuticles’ on dung beetles, or responsive stretching polymer chains as the ‘secretion’ behavior may be, perhaps, clumsy, but it seemed to work perfectly microscopically — the report1 only test the adhesiveness of the so-synthesized surface by atomic forced microscopy, that is at an atomic scale.
But we have a positive experience in the relation between atomic and macroscopic effects in terms of adhesive properties. The well known gecko foot mimic was also first tested by atomic forced microscopy in the Nature article by H. Lee et al.3, and lately demonstrated by Zhonglin Wang macroscopically4 with similar molecular design. I look forward to a macroscopic test for this non-adhesive counterpart.
1 Roman Sheparovych, Mikhail Motornov, Sergiy Minko (2009). Low Adhesive Surfaces that Adapt to Changing Environments Advanced Materials DOI: 10.1002/adma.200802449
2 I LUZINOV, S MINKO, V TSUKRUK (2004). Adaptive and responsive surfaces through controlled reorganization of interfacial polymer layers Progress in Polymer Science, 29 (7), 635-698 DOI: 10.1016/j.progpolymsci.2004.03.001
3 Haeshin Lee, Bruce P. Lee, Phillip B. Messersmith (2007). A reversible wet/dry adhesive inspired by mussels and geckos Nature, 448 (7151), 338-341 DOI: 10.1038/nature05968
4 L. Qu, L. Dai, M. Stone, Z. Xia, Z. L. Wang (2008). Carbon Nanotube Arrays with Strong Shear Binding-On and Easy Normal Lifting-Off Science, 322 (5899), 238-242 DOI: 10.1126/science.1159503... Read more »
Roman Sheparovych, Mikhail Motornov, & Sergiy Minko. (2009) Low Adhesive Surfaces that Adapt to Changing Environments. Advanced Materials. DOI: 10.1002/adma.200802449
I LUZINOV, S MINKO, & V TSUKRUK. (2004) Adaptive and responsive surfaces through controlled reorganization of interfacial polymer layers. Progress in Polymer Science, 29(7), 635-698. DOI: 10.1016/j.progpolymsci.2004.03.001
Haeshin Lee, Bruce P. Lee, & Phillip B. Messersmith. (2007) A reversible wet/dry adhesive inspired by mussels and geckos. Nature, 448(7151), 338-341. DOI: 10.1038/nature05968
L. Qu, L. Dai, M. Stone, Z. Xia, & Z. L. Wang. (2008) Carbon Nanotube Arrays with Strong Shear Binding-On and Easy Normal Lifting-Off. Science, 322(5899), 238-242. DOI: 10.1126/science.1159503
- February 17, 2009
- 07:19 AM
- 1,171 views
Man-Made but Living Systems - Bio Besides Mimetics and Inspirations
by Andrew Sun in On The Road
According to Wikipedia.org which though is not often desirable, the meaning of the word biomimetics does not include the direct utilization of the functional part of living structures. We have found lotus leaves superhydrophobic. But biomimetically we didn’t directly grow lotus crops for water-repelling coatings, nor did we try to culture similar layer from lotus tissue. Rather, we got ‘inspired’ and started ‘mimicking’ the structure by purely artificial technologies we are familiar with. Similar situation is in computer science—obviously we didn’t try to clone some people exclusively for intellectual production, leaving us a comfortable yet improving future without necessity to think over anything complex. Rather, we turn to silicon-based computers and only wish these computers can become smarter by mimicking the logical structure of brain—what the cyberneticists are doing. There seems to be a far future perspective of biomimetics where we will have learned how all the living things work in the planet. At that time we will be alright living without any other living things because they are no longer mysterious or fascinating. Or in other words, at that time we will never fear of the extinction of living things because they are no longer Nature’s monopoly; we can create all living things from bottom up.
However, today’s reality does not seem to allow such an biomimetic optimism. Although some structural tricks have been played by scientists, we are still generally helpless in front of the core mechanism of life. Currently we have learned very little from Nature as we estimate, and our biomimetic products are essentially nonliving. While the genius of Natural gifts are extincting at a much faster way than human can catch up, we now still need to rely on living things in many crucial aspects of life besides foods.
Energy source of the matrix in the movie Matrix. From Jason Kurtz’s website.
Whereas biomimetics wishes us to rely less on ecology, with little real success, another idea wishes us to rely more, by exploring the nature and finding new living species that may potentially work for human. The logic is somewhat similar to ‘to grow crops of lotus for water-repelling coating’, but practically this kind of research focus primarily on biofuels, agricultural technology (e.g. mix planting), etc. Although this kind of idea can still be ethically scary if pushed to some extreme (remember the energy producing units in the movie Matrix), it still sounds better than a biomimetic claim that we will kill all fauna and flora when we have known them all (at least in Matrix we still have human).
Shewanella. From http://www.ornl.gov.
And sometimes this kind of research is also seen in materials science. A group of Japanese scientists recently published a paper1 on Angew. Chem. Int. Ed. describing a electrically conductive bacterial network under some artificial manipulation—a man-made material that functions only when it’s living. The featured bacterium is called Shewanella, which is known capable to recognize and transfer electrons to Fe(III) oxide surfaces2. The researchers found that, although individual cells are electrically
insulated from the others, addition of semiconducting Fe2O3 colloidal particles to the bacterial culture resulted in a continuous film that is found electrically conductive, provided the food for the bacteria, lactate, is sufficient. It is proved that the conductivity of the film is the result of bacteria, not the added Fe2O3 colloids, because pure this colloids were found electrically isolate. The authors said in the paper that this finding is relevant to “designing and fabricating bioanode materials for microbial fuel cells”.
This paper reminded me another earlier one3 published on Adv. Mater., where cells were added to a solution of polymer which is modified with cell recepters, resulting a bio-crosslinked hydrogel. The sol-to-gel transition was characterized by rheological method implying some mechanical properties of the so-formed hydrogel. This cell-croslinking hydrogel was further found reversible—it flows when sheared, and gels again when allowed to stand for a while. This property is important for injectable gel drugs that allow the drug can pass through the syringe while can stay at one place after injection, curing specifically the lesion site. What if we can inject some living cell amendment instead?! And, considering also the former electrical bacteria, what if we can inject some living electronic devices into our bodies where they keep functioning so long as our bodies provide them nutrients for living?
That may be a totally different scene from what biomimetics provides.
1 Ryuhei Nakamura, Fumiyoshi Kai, Akihiro Okamoto, Greg J. Newton, Kazuhito Hashimoto (2009). Self-Constructed Electrically Conductive Bacterial Networks Angewandte Chemie International Edition, 48 (3), 508-511 DOI: 10.1002/anie.200804750
2 Gemma Reguera, Kevin D. McCarthy, Teena Mehta, Julie S. Nicoll, Mark T. Tuominen, Derek R. Lovley (2005). Extracellular electron transfer via microbial nanowires Nature, 435 (7045), 1098-1101 DOI: 10.1038/nature03661
3 K.Y. Lee, H.J. Kong, R.G. Larson, D.J. Mooney (2003). Hydrogel Formation via Cell Crosslinking Advanced Materials, 15 (21), 1828-1832 DOI: 10.1002/adma.200305406... Read more »
Ryuhei Nakamura, Fumiyoshi Kai, Akihiro Okamoto, Greg J. Newton, & Kazuhito Hashimoto. (2009) Self-Constructed Electrically Conductive Bacterial Networks. Angewandte Chemie International Edition, 48(3), 508-511. DOI: 10.1002/anie.200804750
Gemma Reguera, Kevin D. McCarthy, Teena Mehta, Julie S. Nicoll, Mark T. Tuominen, & Derek R. Lovley. (2005) Extracellular electron transfer via microbial nanowires. Nature, 435(7045), 1098-1101. DOI: 10.1038/nature03661
K.Y. Lee, H.J. Kong, R.G. Larson, & D.J. Mooney. (2003) Hydrogel Formation via Cell Crosslinking. Advanced Materials, 15(21), 1828-1832. DOI: 10.1002/adma.200305406
- February 13, 2009
- 07:19 AM
- 1,395 views
Liquid Mirrors
by Andrew Sun in On The Road
Liquid Mirror Telescope
The first time I heard that liquid mirrors worth studying was from a Nature‘s News & Views article. Rotating liquid that creates a parabolic surface enables human to conceive about really big telescopes that have to be built on the moon. The Nature article praised the use of ionic liquid, liquid with ’nearly zero’ vapor pressure, for liquid mirror support, because in the moon the working environment is vacuum. And it is also cold there, so the liquid mirror should also melt at as low a temperature as possible.
Then it started to seem that all researching or manufacturing efforts on reflective liquid droplets were for the future, exciting, lunar application, at least for me, who only heard of these things from the moon fantasy. Afterward I kept being informed by various science news agents of the same moon fantasy (NewScientist, NASA, the MIT based Technology Reviews, etc.), although I also knew more that liquid mirror for telescope is not new. NASA has one – a 3-meter Liquid Mirror Telescope (LMT) for tracking orbital debris:
Image from the NASA Orbital Debris Program Office
The liquid used in this ‘Earth version’ is mercury. The man in the photo was not committing suicide because the surface of mercury was covered by a layer of oxide which prevent the mercury to evaporate. But this is not likely to work on the moon where the pressure is much lower and things are much more ready to evaporate. So it can be said that ionic liquid have saved the crazy idea of lunar liquid mirror telescope, and will realize an ongoing lunar liquid mirror telescope project.
An Ancient Project
The legend of Archimedes’s weapon
The idea of “mobile” curved mirror is not new, although there have been many debates on the historical existence of the mirrors as “weapons of mass destruction” in ancient Greece implemented by Archimede – the Death Ray, in which multiple mirrors were arranged to concentrate the sun light and set the enemy in fire. Not only is it theoretically doubtful, but experimentally, an MIT group also indicated that the effect of this kind of weapon was exaggerated. The experiment was only able to set a small fire on one ship at half the distance described in the legend, and that fire was quickly extincted. Some authors even suspected the translation of the ancient Greek word πυρεια referring the very object used as weapon in the concerned war as mirrors. However, knowledge of the concentrating effect of curvature on a mirror seems to have indeed established early. No matter the legend of the Death Ray was true or not, at least there must have been someone conceiving many normal-scale plain mirrors to assemble a large-scale, ‘mobile’, curved reflective surface.
Stories in Smaller Scales
And this seems to have been realized in a much smaller scale recently. Researchers from different universities cooperated to assemble tiny hexagonal mirrors along the interface between an oil droplet and the surrounding water bath, thus created a liquid mirror droplet. The tiny mirrors are actually hydrophilic, transparent silicon platelets 8 μm in diameter and 1μm thick, fabricated by lithography. Each platelet is then covered by gold on one side (hydrophilic). When the mirror platelets was injected into the oil droplet submerged in water bath, the platelets gradually migrated to the water/oil interface with the gold side facing toward the oil phase, forming a curved reflective surface. Moreover, the researchers were able to alter the curvature of the droplet by electrowetting method, making the focus length of the liquid mirror tunable.
Tunable liquid mirror. Langmuir ASAP Article. Permission obtained from Rightslink
This work’s perspective differs quite largely from the above mentioned large scale lunar project, in that suspending droplets with enhanced boundary optical properties are also a promising step toward tunable optofluidic devices for cell, microparticle, and even nanoparticle manipulation in a really small scale world.
Robin D. Rogers (2007). Materials science: Reflections on ionic liquids Nature, 447 (7147), 917-918 DOI: 10.1038/447917a
A.S. Papadogiannis, N.S. Papadogianni, A. Carabelas, S. Tsitomeneas, P. Kyraggelos, T.G. Chondros (2008). The Mirror Weapon in Archimedes Era Proceedings of EUCOMES 08, 29-36 DOI: 10.1007/978-1-4020-8915-2_4
D. L. Simms (1991). Galen on Archimedes: Burning Mirror or Burning Pitch? Technology and Culture, 32 (1), 91-96
Michael A. Bucaro, Paul R. Kolodner, J. Ashley Taylor, Alex Sidorenko, Joanna Aizenberg, Tom N. Krupenkin (2008). Tunable Liquid Optics: Electrowetting-Controlled Liquid Mirrors Based on Self-Assembled Janus Tiles Langmuir DOI: 10.1021/la803537v... Read more »
Robin D. Rogers. (2007) Materials science: Reflections on ionic liquids. Nature, 447(7147), 917-918. DOI: 10.1038/447917a
A.S. Papadogiannis, N.S. Papadogianni, A. Carabelas, S. Tsitomeneas, P. Kyraggelos, & T.G. Chondros. (2008) The Mirror Weapon in Archimedes Era . Proceedings of EUCOMES 08, 29-36. DOI: 10.1007/978-1-4020-8915-2_4
D. L. Simms. (1991) Galen on Archimedes: Burning Mirror or Burning Pitch?. Technology and Culture, 32(1), 91-96. DOI: http://www.jstor.org/stable/3106011
Michael A. Bucaro, Paul R. Kolodner, J. Ashley Taylor, Alex Sidorenko, Joanna Aizenberg, & Tom N. Krupenkin. (2008) Tunable Liquid Optics: Electrowetting-Controlled Liquid Mirrors Based on Self-Assembled Janus Tiles. Langmuir, 2147483647. DOI: 10.1021/la803537v
- February 12, 2009
- 12:58 PM
- 1,124 views
Snake Robot
by Andrew Sun in On The Road
A review on snake-inspired robot design was published on the IOP journal, Bioinspirations and Biomimetics, 2009 ,4, 021001. DOI: 10.1088/1748-3182/4/2/021001. The introduction paragraphs of the review described several advantages of snake-like robot compared with other types of design, which is quite interesting to read. But I did not go into the detail of the review. There are images of various design of snake robots in this paper. And this reminds me to search some videos in Youtube.com. It seems that these robots don’t just move like snakes. They also moves like worms, or something not seen in nature.
This video shows many motions of a snake-like robot. I’ve never seen a real snake climb up a tree, like that!
And this is one of the few snake-like robots that really move like a snake.
This poor little worm was stuck on the wall for minutes.
James K Hopkins, Brent W Spranklin, Satyandra K Gupta (2009). A survey of snake-inspired robot designs Bioinspiration & Biomimetics, 4 (2) DOI: 10.1088/1748-3182/4/2/021001... Read more »
James K Hopkins, Brent W Spranklin, & Satyandra K Gupta. (2009) A survey of snake-inspired robot designs. Bioinspiration , 4(2), 21001. DOI: 10.1088/1748-3182/4/2/021001
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