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The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial agility is often impaired when maneuvers require burst-propulsion. Herein we develop highaspect ratio (150:1), multiwalled carbon nanotube microarray membranes (CNT-MMs) for propulsive, MUV thrust generation by the decomposition of hydrogen peroxide (H 2 O 2 ). The CNT-MMs are grown via chemical vapor deposition with diamond shaped pores (nominal diagonal dimensions of 4.5 × 9.0 μm) and subsequently decorated with urchin-like, platinum (Pt) nanoparticles via a facile, electroless, chemical deposition process. The Pt-CNT-MMs display robust, high catalytic ability with an effective activation energy of 26.96 kJ mol -1 capable of producing a thrust of 0.209 ± 0.049 N from 50% [w/w] H 2 O 2 decomposition within a compact reaction chamber of eight Pt-CNT-MMs in series. A n upward trend in the research and use of unmanned underwater vehicles (UUVs), and in particular micro underwater vehicles (MUVs, small UUVS between 1 and 50 cm in length), for exploration of confined spaces such as ship wrecks, submerged oil pipelines, and various military purposes has been observed over recent years. 1À3 The locomotion of these vehicles is typically controlled by propellerbased systems, which are often used for long-endurance missions. 4À6 However, propeller-based systems are usually limited in their ability to perform tight radius turns, burst-driven docking maneuvers, and lowspeed course corrections. ABSTRACT The utility of unmanned micro underwater vehicles (MUVs) is paramount for exploring confined spaces, but their spatial

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Carbon-nanotube-templated microfabrication (CNT-M) of porous materials is demonstrated. Partial chemical infi ltration of 3D carbon-nanotube structures with silicon results in a mechanically robust material, structured from the 10 nm scale to the 100 μ m scale. The nanoscale dimensions are determined by the diameter and spacing of the resulting silicon/carbon nanotubes, while the microscale dimensions are controlled by the lithographic patterning of the CNT growth catalyst. We demonstrate the utility of this hierarchical structuring approach by using CNT-M to fabricate thin-layer-chromatography (TLC) separations media with precise microscale channels for fl uid-fl ow control and nanoscale porosity for high analyte capacity. Chemical separations done on the CNT-M-structured media outperform commercial highperformance TLC media.

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Efficient techniques for computing axisymmetric non-neutral plasma equilibria are described. These equilibria may be obtained either by requiring global thermal equilibrium, by specifying the midplane radial density profile, or by specifying the radial profile of sn dz. Both splines and finite-differences are used, and the accuracy of the two is compared by using a new characterization of the thermal equilibrium density profile which gives a simple formula for estimating the radial and axial gradient scale lengths of thermal equilibria. It is found that for global thermal equilibrium 1% accuracy is achieved with splines if the distance between neighboring splines is about two Debye lengths while finite differences require a grid spacing of about one-half Debye length to achieve the same accuracy.

We apply a suite of analytical tools to characterize materials created in the production of microfabricated thin layer chromatography plates. Techniques used include X-ray photoelectron spectroscopy (XPS), valence band spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) in both positive and negative ion modes, Rutherford backscattering spectroscopy (RBS), and helium ion microscopy. Materials characterized include: the Si(100) substrate with native oxide: Si/SiO 2 , alumina (35 nm) deposited as a diffusion barrier on the Si/SiO 2 : Si/SiO 2 /Al 2 O 3 , iron (6 nm) thermally evaporated on the Al 2 O 3 : Si/SiO 2 /Al 2 O 3 /Fe, the iron film annealed in H 2 to make Fe catalyst nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP), and carbon nanotubes (CNTs) grown from the Fe nanoparticles: Si/SiO 2 /Al 2 O 3 /Fe(NP)/CNT. The Fe films and nanoparticles appear in an oxidized state. Some of the analyses of the CNTs/CNT forests appear to be unique: (i) the CNT forest appears to exhibit an interesting 'channeling' phenomenon by RBS, (ii) we observe an odd-even effect in the SIMS spectra of C n -species for n = 1 -6, with the n ≥ 6 ions showing a steady decrease in intensity, and (iii) valence band characterization of CNTs using X-radiation is reported. Initial analysis of the CNT forest by XPS shows that it is 100 at.% carbon. After one year, only ca. 0.25 at.% oxygen is observed. The information obtained from the combination of the different analytical tools provides a more complete understanding of our materials than a single technique, which is analogous to the story of 'The Blind Men and the Elephant'. The raw XPS and ToF-SIMS spectra from this study will be submitted to Surface Science Spectra for archiving.

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