Composition of Near-Earth Asteroid 2008 EV5: Potential target for Robotic and Human Exploration

We observed potentially hazardous asteroid (PHA) 2008 EV5 in the visible (0.30-0.92 microns) and near-IR (0.75-2.5 microns) wavelengths to determine its surface composition. This asteroid is especially interesting because it is a potential target for two sample return mission proposals (Marco Polo-R and Hayabusa-2) and human exploration due to its low delta-v for rendezvous. The spectrum of 2008 EV5 is essentially featureless with exception of a weak 0.48-microns spin-forbidden Fe3+ absorption band. The spectrum also has an overall blue slope. The albedo of 2008 EV5 remains uncertain with a lower limit at 0.05 and a higher end at 0.20 based on thermal modeling. The Busch et al. (2011) albedo estimate of 0.12 is consistent with our thermal modeling results. The albedo and composition of 2008 EV5 are also consistent with a C-type taxonomic classification (Somers et al. 2008). The best spectral match is with CI carbonaceous chondrites similar to Orgueil, which also have a weak 0.48-microns feature and an overall blue slope. This 0.48-microns feature is also seen in the spectrum of magnetite. The albedo of CI chondrites is at the lower limit of our estimated range for the albedo of 2008 EV5.Comment: Pages: 19 Figures: 6 Tables:

Use of standard metabolic rate as an indicator of environmental stress in redbreast sunfish, Lepomis Auritus

Fish exposed to sub-lethal levels of toxicant-induced stress exhibit physiological and biochemical changes that may result in significant population and community level consequences. Standard metabolic rate integrates the total system response of the organism and thus may provide a good indicator of how well the fish is functioning in its environment. In this study, standard metabolic rate was determined for redbreast sunfish (Lepomis auritus) from two streams: 1) a test stream subject to inputs of various heavy metals, organics, and other toxicants, and 2) a reference stream of similar size and hydrology without industrial or municipal inputs. Fish were tested in their home stream water, in dechlorinated tap water, in test stream water containing suspended contaminated sediment, and in water from a section of the test stream composed primarily of industrial effluent and supporting no resident fish population. No significant difference was noted among any of these test groups with the exception of the group tested in the industrial effluent. This group had significantly reduced standard metabolic rates, probably due to gill damage resulting from exposure to chlorine in the water. These results suggest that standard metabolic rate is not a adequate indicator of the effects of chronic exposure to sublethal stressors

NPMS

Thesis (S.M. in Naval Architecture and Marine Engineering and S.M. in Mechanical Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 73).This thesis presents an approach to the structural design and optimization of a non-pressurized manned submersible (NPMS), a type of fully "flooded" submersible based on a SEAL Delivery Vehicle (SDV) Design Concept. Using the design parameters determined by the mathematical model, a solid model was generated and an ANSYS goal-driven optimizer was used to further optimize the hull weldment and variable ballast tanks. When three different designs were subsequently evaluated to verify the parametric model and the scalability of the NPMS design concept, all three were found to be able to be successfully generated and to meet the stated design requirements after ANSYS optimization. These findings indicate that the approach presented in this thesis can be used as an initial design tool in the future design of NPMSs.by Kenneth Shepard.S.M.in Naval Architecture and Marine Engineering and S.M.in Mechanical Engineerin

TB152: The Effect of Juvenile Wood on the Properties of Aspen Flakeboard

While the effects of juvenile wood tissue on solid wood products and paper have been known for some time, little information is available regarding its influence on structural flakeboard. Juvenile and mature wood tissue were identified b y their physical and mechanical properties in quaking aspen (Populus tremuloides Michx.). Sections of juvenile and mature wood were separated from 1-foot bolts of aspen. These sections were used to prepare three distinct types of structural flakeboard : juvenile wood-based, mature wood-based, and one formed from an equal mixture of the two. The panels were tested for selected mechanical and physical properties. The juvenile wood-based panels performed significantly better than the mature wood-based in respect to modulus of rupture, thickness swell, and water absorption, while also exhibiting somewhat higher values for modulus of elasticity, internal bond strength, compressive shear strength, and linear expansion. The panels made with a mixture of the two types of flakes did not display some of the poorer characteristics of the mature wood panels.https://digitalcommons.library.umaine.edu/aes_techbulletin/1052/thumbnail.jp

Focused Ion Beam Fabrication

Contains reports on thirteen research projects and a list of publications.Defense Advanced Research Projects Agency/U.S. Army Research Office Contract DAAL03-88-K-0108National Science Foundation Grant ECS 89-21728MIT Lincoln Laboratory Innovative Research ProgramSEMATECH Contract 90-MC-503Micrion Contract M08774U.S. Army Research Office Contract DAAL03-87-K-0126IBM Corporatio

Integrated circuit-based electrochemical sensor for spatially resolved detection of redox-active metabolites in biofilms

Despite advances in monitoring spatiotemporal expression patterns of genes and proteins with fluorescent probes, direct detection of metabolites and small molecules remains challenging. A technique for spatially resolved detection of small molecules would benefit the study of redox-active metabolites that are produced by microbial biofilms and can affect their development. Here we present an integrated circuit-based electrochemical sensing platform featuring an array of working electrodes and parallel potentiostat channels. ‘Images’ over a 3.25 0.9 mm2 area can be captured with a diffusion-limited spatial resolution of 750 mm. We demonstrate that square wave voltammetry can be used to detect, identify and quantify (for concentrations as low as 2.6 mM) four distinct redox-active metabolites called phenazines. We characterize phenazine production in both wild-type and mutant Pseudomonas aeruginosa PA14 colony biofilms, and find correlations with fluorescent reporter imaging of phenazine biosynthetic gene expression

Host Cell Transcriptome Profile during Wild-Type and Attenuated Dengue Virus Infection

10.1371/journal.pntd.0002107PLoS Neglected Tropical Diseases73

A Single-Photon Avalanche Diode Imager for Fluorescence Lifetime Applications

A 64-by-64-pixel CMOS single-photon avalanche diode (SPAD) imager for time-resolved fluorescence detection features actively quenched and reset pixels, allowing gated detection to eliminate pile-up nonlinearities common to most time-correlated single-photon counting (TCSPC) approaches. Timing information is collected using an on-chip time-to-digital converter (TDC) based on a counter and a supply-regulated delay-locked loop (DLL)