Investigation of the Electrochemical Behaviour of MWCNTs in the detection of Cr(VI)

The electrochemical behaviour of a glassy carbon (GC) electrode modified with MWCNTs was investigated and characterised using K3[Fe(CN)6] as a probe. An increase in the electroactive surface area and the rate of electron transfer was observed on sonication of the MWCNTs prior to casting at the GC electrode. The modified electrode was also used in the detection of Cr(VI) in both pH 5.0 and pH 2.0 aqueous solutions. Better detection limits were obtained in the acidic solution

On the Proof of Dark Matter, the Law of Gravity and the Mass of Neutrinos

We develop a new method to predict the density associated with weak lensing maps of (un)relaxed clusters in a range of theories interpolating between GR and MOND (General Relativity and Modified Newtonian Dynamics). We apply it to fit the lensing map of the bullet merging cluster 1E0657-56, in order to constrain more robustly the nature and amount of collisionless matter in clusters {\it beyond} the usual assumption of spherical equilibrium (Pointecouteau & Silk 2005) and the validity of GR on cluster scales (Clowe et al. 2006). Strengthening the proposal of previous authors we show that the bullet cluster is dominated by a collisionless -- most probably non-baryonic -- component in GR as well as in MOND, a result consistent with the dynamics of many X-ray clusters. Our findings add to the number of known pathologies for a purely baryonic MOND, including its inability to fit the latest data from the Wilkinson Microwave Anisotropy Probe. A plausible resolution of all these issues and standard issues of Cold Dark Matter with galaxy rotation curves is the "marriage" of MOND with ordinary hot neutrinos of 2eV. This prediction is just within the GR-independent maximum of neutrino mass from current $\beta$-decay experiments, and is falsifiable by the Karlsruhe Tritium Neutrino (KATRIN) experiment by 2009. Issues of consistency with strong lensing arcs and the large relative velocity of the two clusters comprising the bullet cluster are also addressed.Comment: 4 pages, 1 figure, accepted for publication in ApJL. Added a simple model of the bullet cluster's high velocity in TeVeS, and discussions of sterile neutrinos and of non-uniqueness of the lensing deprojectio

Chemical and physical properties of bulk aerosols within four sectors observed during TRACE-P

Chemical and physical aerosol data collected on the DC-8 during TRACE-P were grouped into four sectors based on back trajectories. The four sectors represent long-range transport from the west (WSW), regional circulation over the western Pacific and Southeast Asia (SE Asia), polluted transport from northern Asia with substantial sea salt at low altitudes (NNW) and a substantial amount of dust (Channel). WSW has generally low mixing ratios at both middle and high altitudes, with the bulk of the aerosol mass due to non-sea-salt water-soluble inorganic species. Low altitude SE Asia also has low mean mixing ratios in general, with the majority of the aerosol mass comprised of non-sea-salts, however, soot is also relatively important in this region. NNW had the highest mean sea salt mixing ratios, with the aerosol mass at low altitudes (\u3c2 km) evenly divided between sea salts, non-sea-salts, and dust. The highest mean mixing ratios of water-soluble ions and soot were observed at the lowest altitudes (\u3c2 km) in the Channel sector. The bulk of the aerosol mass exported from Asia emanates from Channel at both low and midaltitudes, due to the prevalence of dust compared to other sectors. Number densities show enhanced fine particles for Channel and NNW, while their volume distributions are enhanced due to sea salt and dust. Low-altitude Channel exhibits the highest condensation nuclei (CN) number densities along with enhanced scattering coefficients, compared to the other sectors. At midaltitudes (2–7 km), low mean CN number densities coupled with a high proportion of nonvolatile particles (≥65%) observed in polluted sectors (Channel and NNW) are attributed to wet scavenging which removes hygroscopic CN particles. Low single scatter albedo in SE Asia reflects enhanced soot

Ecological Characteristics of Streams in the Barrenlands near Lac de Gras, N.W.T., Canada

We examined spatiotemporal variation in the physical, chemical, and biological characteristics of pristine streams that represent a range of conditions near Lac de Gras in the Barrenlands region of the Northwest Territories, Canada. Principal component analysis organized streams into four groups on the basis of seven physical characteristics. Despite broad differences among groups in physical characteristics, variation in chemical and biological characteristics was generally not large, with only pH and coarse particulate organic matter differing among the four groups. Nevertheless, several chemical and biological variables were correlated with physical characteristics, particularly measures of stream size (bankfull width and depth, drainage area, and stream discharge). Annual variability in climate affected stream temperature and discharge and influenced several biotic characteristics, particularly the growth of young-of-the-year arctic grayling (Thymallus arcticus). Barrenland streams share basic characteristics of Alaskan tundra streams, as a result of similar climatic regimes. Key differences between the two areas, however, appear related to the lake-outlet nature of the Barrenland streams, which may contribute to higher growth of young-of-the-year arctic grayling than would be expected from regional climate.On a étudié la variation spatio-temporelle dans les caractéristiques physiques, chimiques et biologiques de cours d'eau vierges qui témoignent d'une gamme de conditions près du lac de Gras dans la région des Barrenlands, dans les Territoires du Nord-Ouest, au Canada. L'analyse des composantes principales a divisé les cours d'eau en quatre groupes, d'après sept caractéristiques physiques. En dépit de différences marquées dans ces dernières entre les groupes, la variation dans les attributs chimiques et biologiques n'était généralement pas très grande, avec seulement le pH et les grosses particules organiques qui montraient des différences entre les quatre groupes. Plusieurs variables chimiques et biologiques étaient néanmoins corrélées avec les attributs physiques, en particulier les mesures de la taille des cours d'eau (largeur et profondeur du débordement, aire de drainage et débit). La variabilité annuelle du climat avait une incidence sur la température et le débit des cours d'eau et elle influençait plusieurs caractéristiques biotiques, en particulier la croissance des jeunes de l'année chez l'ombre arctique. Les cours d'eau des Barrenlands ont en commun les caractéristiques fondamentales des cours d'eau de la toundra alaskienne, vu qu'ils sont soumis à des régimes climatiques similaires. Les différences majeures entre les deux régions semblent cependant liées au fait que la décharge des cours d'eau des Barrenlands se fait dans un lac, ce qui pourrait contribuer à une croissance des jeunes de l'année chez l'ombre arctique plus forte que le climat régional ne le laisserait croire

NASA's Space Launch System Progress Report

Exploration beyond Earth will be an enduring legacy for future generations, confirming America's commitment to explore, learn, and progress. NASA's Space Launch System (SLS) Program, managed at the Marshall Space Flight Center, is responsible for designing and developing the first exploration-class rocket since the Apollo Program's Saturn V that sent Americans to the Moon. The SLS offers a flexible design that may be configured for the MultiPurpose Crew Vehicle and associated equipment, or may be outfitted with a payload fairing that will accommodate flagship science instruments and a variety of high-priority experiments. Both options support a national capability that will pay dividends for future generations. Building on legacy systems, facilities, and expertise, the SLS will have an initial lift capability of 70 metric tons (mT) and will be evolvable to 130 mT. While commercial launch vehicle providers service the International Space Station market, this capability will surpass all vehicles, past and present, providing the means to do entirely new missions, such as human exploration of asteroids and Mars. With its superior lift capability, the SLS can expand the interplanetary highway to many possible destinations, conducting revolutionary missions that will change the way we view ourselves, our planet and its place in the cosmos. To perform missions such as these, the SLS will be the largest launch vehicle ever built. It is being designed for safety and affordability - to sustain our journey into the space age. Current plans include launching the first flight, without crew, later this decade, with crewed flights beginning early next decade. Development work now in progress is based on heritage space systems and working knowledge, allowing for a relatively quick start and for maturing the SLS rocket as future technologies become available. Together, NASA and the U.S. aerospace industry are partnering to develop this one-of-a-kind asset. Many of NASA's space centers across the country will provide their unique expertise to the Space Launch System endeavor. Unique infrastructure to be used includes the Michoud Assembly Facility for tank manufacturing, Stennis Space Center for engine testing, and Kennedy Space Center for processing and launch. As this panel will discuss, the SLS team is dedicated to doing things differently-from applying lean oversight/insight models to smartly using legacy hardware and existing facilities. Building on the foundation laid by over 50 years of human and scientific space flight--and on the lessons learned from the Apollo, Space Shuttle, and Constellation Programs-the SLS team has delivered both technical trade studies and business case analyses to ensure that the SLS architecture will be safe, affordable, reliable, and sustainable

Training Models in Professional Psychology Education (A Literature Review)

Intense debate on training models used in professional psychology education, including discussion on the specific training models most appropriate for educating future psychologists is far from finished. The authors reviewed articles discussing training models including results of empirical studies in professional psychology programs, which were published in several psychology journals databases (1949 to 2014). The authors have identified (a) the scientist-practitioner; (b) the practitioner model and its derivatives; (c) the clinical-scientist; and (d) the competency-based models. This article also outlines the historical development of each model and a consideration of the main principles espoused by each training model. It seems that discussion on the concept of training models and empirical studies on how these models are used in professional psychology programs outside the context of Western countries, is rare. Thus, this review could serve as a theoretical foundation for the implementation of a study aimed at filling the gap in the discussion of professional psychology program curricula, including the training models used, especially in other contexts than the Western

Conducting Planetary Field Geology on EVA: Lessons from the 2010 DRATS Geologist Crewmembers

In order to prepare for the next phase of planetary surface exploration, the Desert Research and Technology Studies (DRATS) field program seeks to test the next generation of technology needed to explore other surfaces. The 2010 DRATS 14-day field campaign focused on the simultaneous operation of two habitatable rovers, or Space Exploration Vehicles (SEVs). Each rover was crewed by one astronaut/commander and one geologist, with a change in crews on day seven of the mission. This shift change allowed for eight crew members to test the DRATS technology and operational protocols [1,2]. The insights presented in this abstract represent the crew s thoughts on lessons learned from this field season, as well as potential future testing concepts

Desert Rats 2010 Operations Tests: Insights from the Geology Crew Members

Desert Research and Technology Studies (Desert RATS) is a multi-year series of tests of NASA hardware and operations deployed in the high desert of Arizona. Conducted annually since 1997, these activities exercise planetary surface hardware and operations in relatively harsh conditions where long-distance, multi-day roving is achievable. Such activities not only test vehicle subsystems, they also stress communications and operations systems and enable testing of science operations approaches that advance human and robotic surface exploration capabilities. Desert RATS 2010 tested two crewed rovers designed as first-generation prototypes of small pressurized vehicles, consistent with exploration architecture designs. Each rover provided the internal volume necessary for crewmembers to live and work for periods up to 14 days, as well as allowing for extravehicular activities (EVAs) through the use of rear-mounted suit ports. The 2010 test was designed to simulate geologic science traverses over a 14-day period through a volcanic field that is analogous to volcanic terrains observed throughout the Solar System. The test was conducted between 31 August and 13 September 2010. Two crewmembers lived in and operated each rover for a week with a "shift change" on day 7, resulting in a total of eight test subjects for the two-week period. Each crew consisted of an engineer/commander and an experienced field geologist. Three of the engineer/commanders were experienced astronauts with at least one Space Shuttle flight. The field geologists were drawn from the scientific community, based on funded and published field expertise