Nanoscale Zero Valent Iron for Environmental Cadmium Metal Treatment

In the course of developing methods to treat heavy metal contaminants in wastewater, nanoscale zerovalent iron (nZVI) has been found to be an alternative approach. This nanoparticle has been used to remove metals such as Cr6+, Cu2+, Pb2+, Ba2+, As3+, As5+, and Co2+ from aqueous solutions. Iron nanoparticles are useful for decontamination purposes due to their smaller size, surface area-to-weight ratio, and capacity to remove groundwater contaminants. The large specific surface area of the iron nanoparticles further fosters enhanced reactivity for the transformation of environmental pollutants. Because of their smaller size, nanoscale-based iron materials are much more reactive than conventional iron powders, and they can be suspended in slurry and pumped straight to the contaminated site. The ZVI is often applied for the remediation of wastewater or groundwater with several kinds of reducible contaminants, which are near its surface reduction potential. This chapter seeks to present the efficiency of zerovalent iron nanoparticles (nZVI) to remedy the cadmium ion pollution in water as well as the use of the remediation product in photoelectrochemical devices

Comparative analysis of alternate MHS configurations

Given the possibility that the passive Microwave Humidity Sounder (MHS) for NASA's Earth Observing System (EOS) may have to be replaced, two alternate configurations are analyzed in this document. One option mirrors AMSU-B, the Advanced Microwave Sounding Unit (AMSU) moisture sounder; which consists of five channels at 89, 150, 183 +/- 1, 183 +/- 3, and 183 +/- 7 GHz. The second option contains an additional channel at 183 +/- 14 GHz and replaces the channels at 89 and 150 GHz with three channels at 118 +/- 0.5, 118 +/- 1.4, and 118 +/- 3 GHz. The latter configuration is considered to be superior due to its greater scientific benefits and reduced cost and complexity -- it would require only two local oscillators and a smaller antenna size for a given resolution on the ground. As shown by means of simulations, humidity profile retrieval accuracy for the second option is superior in most cases and only slightly degraded relative to the first option in the worst-case scenario. The results are summarized. Including the 118-GHz channels also offers the possibility of cell-top altitude retrievals and improved temperature profile retrievals when used in conjunction with a temperature sounder such as the 15-channel AMSU-A

Rapid Orbital Decay in the 12.75-Minute Binary White Dwarf J0651+2844

We report the detection of orbital decay in the 12.75-minute, detached binary white dwarf (WD) SDSS J065133.338+284423.37 (hereafter J0651). Our photometric observations over a 13 month baseline constrain the orbital period to 765.206543(55) s and indicate that the orbit is decreasing at a rate of (-9.8 +/- 2.8) x 10(-12) s s(-1) (or -0.31 +/- 0.09 ms yr(-1)). We revise the system parameters based on our new photometric and spectroscopic observations: J0651 contains two WDs with M-1 = 0.26 +/- 0.04 M-circle dot and M-2 = 0.50 +/- 0.04 M-circle dot. General relativity predicts orbital decay due to gravitational wave radiation of (-8.2 +/- 1.7) x 10(-12) s s(-1) (or -0.26 +/- 0.05 ms yr(-1)). Our observed rate of orbital decay is consistent with this expectation. J0651 is currently the second-loudest gravitational wave source known in the milli-Hertz range and the loudest non-interacting binary, which makes it an excellent verification source for future missions aimed at directly detecting gravitational waves. Our work establishes the feasibility of monitoring this system's orbital period decay at optical wavelengths.NSF AST-0909107, AST-1008734Norman Hackerman Advanced Research Program 003658-0252-2009Astronom

Carbon-based Materials for Extracting Urea to Recycle Waste Water in Space Applications

Recovering water aboard spacecrafts is essential for space exploration. Bringing fresh water to outer space for crew members is an expensive process. Therefore, recycling waste water to usable water is necessary for long term space missions and applications. Previous experiments showed that urea, which is the main substance in urine, prematurely fouled the membrane used in the water treatment process. In this experiment we investigated different carbon-based materials to act as a urea pre-treatment step. A total of nine different materials were tested for the amount of urea they can adsorb. The adsorption rate will enable us to decide which material is best for the pre-treatment process. Out of nine adsorbents, three had good adsorption rate with over 90% of urea is adsorbed

Changes in drought tolerance of Pinus radiata in Chile associated with provenance and breeding generation

International audienceAbstractKey messageIn Chile, breeding radiata pine for growth has led to drifts in the degree of drought tolerance of the seedlings. Interior provenances gained a larger tolerance to drought after three breeding generations as shown by larger survival and root/shoot ratio under water shortage, while coastal provenance displayed an opposite trend.•Context Given that rainfall is predicted to decrease and to affect establishment and early survival of radiata pine (Pinus radiata D. Don) in Chile, there is a need to identify more drought tolerant genotypes at seedling stage.•Aims The aim of this study was to test whether provenances of P. radiata originating from interior or from coastal provenances, displayed different responses to short-term water shortage, and whether these responses differed from the first to the third breeding generation.•Methods Three generations of breeding families from two sites in Central Chile were compared. The seedlings were grown during 100 days and subjected to two watering regimes for 45 days. Survival, growth, and biomass allocation to roots and shoots were recorded.•Results The two provenances displayed different responses to drought. Biomass allocation to shoots and survival were significantly reduced by water shortage. The first generation seedlings from the coastal provenance displayed a larger survival rate when exposed to water shortage (i.e., 60 %); this rate decreased in the following breeding generations. On the contrary, the survival rate increased from the first to the third generation in the interior provenance.•Conclusions We observed an important local adaptation to water shortage in the interior provenance. This response may be due to the fact that parent tree populations of the interior provenance have successfully adapted to sites with periodic drought

Synthesis and Electrocatalytic Properties of H2SO4-Induced (100) Pt Nanoparticles Prepared in Water-in-Oil Microemulsion

The increasing number of applications for shape-controlled metal nanoparticles (NPs) has led to the need for easy, cheap, and scalable methodologies. We report the synthesis of (100) preferentially oriented Pt NPs, with a particle size of 9 nm, by using a water-in-oil microemulsion method. The specific surface structure of the NPs is induced by the presence of H2SO4 in the water phase of the microemulsion. Interestingly, the results reported herein show how increasing amounts of H2SO4 lead to the formation of Pt NPs containing a larger amount of (100) sites on their surface. This preferential surface orientation is confirmed electrochemically by using the so-called hydrogen adsorption/desorption process. In addition, transmission electron microscopy measurements confirm the presence of cubic-like Pt NPs. Finally, the electrocatalytic properties of the Pt NPs are evaluated towards ammonia and CO electro-oxidations, which are (100) structure-sensitive reactions.This work has been financially supported by the MCINN-FEDER (Spain) (project CTQ 2010-16271), Generalitat Valenciana (project PROMETEO/2009/045) and in part by NASA-URC Grant No. NNX10AQ17A and NSF-NSEC Center for Hierarchical Manufactur-ing Grant No. CHM-CMMI-0531171. R. M-R is grateful to the Becas Iberoamérica, Santander Universidades-España 2012 and PR-LSAMP Bridge to Doctorate Fellowship programs

Arc Stability Characterization of Double Coated Electrodes for Hardfacing

The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing, on the operational behavior (arc stability). For this, three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating, differentiating only in the relative position that occupies the alloy charge (C-Cr-Mn) in the structure of the coating: internal, external and homogeneous. For the development of the research, a completely random design is used. The operative characterization of the electrodes is performed in terms of the arc stability. In conclusion, it can be seen that the position of the alloy load influences the operation behavior (stability of the arc). The variant of internal alloy charge in the coating presents the better arc stability performance

The history of mechanical ventilation

The aim of mechanical ventilation is to substitute physiological respiratory function. The boom of mechanical ventilation came during the XVIII century with the development of Reanimation Societies in Europe, who promoted the use of positive pressure ventilation modes. This type of ventilation caused new complications due to excessive positive pressure in the airway. Therefore, during the XIX century negative pressure ventilation predominated, which became essential during the second half of the 19th century and first half of the 20th century. Positive pressure ventilation was relegated to operating rooms until 1952, when it was imposed over negative pressure ventilation during the Copenhagen polio epidemic. Björn Ibsen contributed significantly to this change of ventilation paradigm, which led to the latest ventilation strategies and the development of the actual intensive care units