Biomolecules as selective dispersants for carbon nanotubes

Both single-wall or multi-wall nanotube growth result in a soot-like material that contains the desired product. The selective recovery of the nanotube product from this soot still represents a challenge. Methods to date either result in chemical modification of the nanotubes themselves, are time consuming or use expensive to produce polymers. Using a variety of biomolecules, we have been able to selectively suspend multi-wall carbon nanotubes in aqueous solutions while leaving behind the extraneous by-products in the precipitate. At comparable biomolecule to soot ratios, all biomolecules selectively retained more nanotubes than an organic polymer previously used to purify multi-wall nanotubes (PmPV—poly m-phenylene-co-2,5-dioctoxy-p-phenylenevinylene). The highest recovery as determined by Electron Paramagnetic Resonance was 56% of the available nanotubes. The method provides a simple, one-step, non-destructive purification process that facilitates the formation of pure multi-wall carbon nanotube containing biodispersions.     

1TB字节有多大

我们部知道，硬盘的储存容量是用字节（Byte）来表示的。1个字节是最小的储存单位。     

Localized irradiation effects on tunnel diode transitions in multi-junction concentrator solar cells

Multi-junction concentrator solar cells incorporate tunnel diodes that undergo a transition from high-conductance tunneling to low-conductance thermal diffusion behavior, typically at threshold current densities of the order of 10²-10³ mA/mm². We present experimental evidence of a prominent heretofore unrecognized dependence of threshold current density on the degree of localized irradiation, in different solar cell architectures. We also show that solar cells with non-uniform metallization can exhibit an additional spatial dependence to the tunnel diode threshold current density. These previously undiscovered phenomena - which should be observable in all non-uniformly irradiated photovoltaic tunnel diodes - are interpreted as being derived from the lateral spreading of excess majority carriers (analogous to current spreading in light-emitting diodes (LEDs)). The consequences for concentrator photovoltaics are addressed.     

Objective and subjective reduction of cellulite volume using a localized vibrational massage device in a 24-week randomized intra-individual single-blind regression study

Cellulite occurs in females and is a common condition of altered connective tissue matrix and increased adipogenicity with visible dimples and orange-peel appearance on the skins surface. Whilst advancements in methods continue to help our understanding, attempts to correct the appearance of cellulite topically have yielded limited success. Various kinds of non-invasive body contouring methods such as whole body vibration have been reported with demonstrable visible improvements in the cellulite condition. The aim of this study was to evaluate volume reduction and improvement of the visible appearance of cellulite as judged both objectively (AEVA-HE phase-shift 3-D fringe projection, macrophotography image grading) and subjectively (questionnaires) after application of a hand-held localized vibrational device over 24-weeks. The study was conducted on 40 healthy female volunteers who were instructed how to use the device on defined areas of cellulite of the outside and rear of the thighs (iliotibial band, and over biceps femoris region respectively). The initial 12 weeks of continuous massage application of the study were followed by a 12 week phase in which volunteers were split into 2 subgroups – one for assessment of regression effects and one for continuous application effects. AEVA (skin surface volume) measurements of cellulite-related dimples correlated with questionnaires and visual image evaluation scoring, in that in the iliotibial region cellulite was significantly reduced at 12 weeks. In the regression subgroup cellulite returned to initial values soon after cessation of treatment, whereas in the continuous application subgroup, cellulite remained diminished. The effect of this device to reduce cellulite as observed in this study proves that continuous use of vibrational massage is beneficial to mitigate visible signs of cellulite.     

Autonomous tracking of an oceanic thermal front by a Wave Glider

Temporal variation in the structure and location of dynamic ocean features make them challenging to observe. Beyond requiring sufficient persistence and speed of the sensor platform, effective observation is augmented by autonomous feature detection coupled with adaptive localization of mapping effort. These capabilities enable observations to remain localized within and around features of interest, thereby enhancing spatial and temporal resolution in their depiction. A Wave Glider is a wave‐propelled unmanned surface vehicle with solar energy collection to support payload and a backup propeller in calm sea state. The efficiency of this platform enables persistence (months), and its propulsion system provides speed (~1 m/s). Building on these capabilities, we aim at enabling the Wave Glider to autonomously recognize and track oceanic features that have strong surface expressions, accessible to near‐surface sensors. We present a method of using a Wave Glider to autonomously track an oceanic thermal front known to have biological importance and dynamic evolution. In October 2017, this method was applied to tracking and mapping an upwelling front in Monterey Bay, CA, over 39 hr. The field result demonstrates adaptive localization of mapping based on autonomous feature detection.     

“Special Issue on Latin-American Research” Maritime Networks,Services Structure and Maritime Trade

This paper aims at investigating the relationship between maritime trade and maritime freight rates at sectoral level. These rates and their effect on international trade will be estimated using highly disaggregated data of shipments from five Spanish ports to seventeen destinations, 78.34% of the tonnage exported by Spain. The paper focuses on the effect of maritime networks, services structure and port infrastructure variables on maritime freight rates. The relationship between freight rates and trade is then analysed by applying a gravity model for sectoral exports. We investigate the endogeneity of the trade and freight rate variables by estimating both equations by using instrumental variables methods. The main findings of this study should contribute significantly in explaining the variability of maritime freight rates and to quantifying the impact of maritime freight rates in maritime trade.     

Risk evaluation for federally listed (roseate tern,piping plover) or candidate (red knot) bird species in offshore waters: A first step for managing the potential impacts of wind facility development on the Atlantic Outer Continental Shelf

With a worldwide increase in attention toward developing a reliance on renewable energy, there is a need to evaluate the effects of these facilities (solar, wind, hydropower) on ecosystems. We conduct a hazard and risk evaluation for three species of birds that are listed, or candidates for listing, as federally threatened or endangered in the US, and that might occur offshore on the Atlantic Outer Continental Shelf (AOCS) where wind power facilities could be developed. Our objectives were to: 1) provide conceptual models for exposure for each species, and 2) examine potential exposure and hazards of roseate tern (Sterna dougallii) and piping plover (Charadrius melodus, both federally endangered in the US) and red knot (Calidris canutus rufa, candidate species) in the AOCS. We used a weight-of-evidence approach to evaluate information from a review of technical literature. We developed conceptual models to examine the relative vulnerability of each species as a function of life stage and cycle (breeding, staging, migratory, wintering). These methods are useful for conducting environmental assessments when empirical data are insufficient for a full risk assessment. We determined that 1) Roseate terns are likely to be exposed to risk during the migratory and breeding season when they occur in the AOCS, as well as while staging. 2) Piping plovers are not likely to be at risk during the breeding season, but may be at risk during spring or fall migrations. Risk to this species is likely to be low from turbines located far from land as this species migrates mainly along the coast. 3) Red knots are potentially exposed to some risk during migration, especially long-distance migrants whose migratory routes take them over the AOCS. More information is required on exact spatio-temporal migration routes, flight altitudes (especially during ascent and descent), and behavioral avoidance of turbines by birds to ascertain their risk.