Science.gov

Sample records for 80 mm hg

  1. Ultrastructural response of rat lung to 90 days' exposure to oxygen at 450 mm Hg

    NASA Technical Reports Server (NTRS)

    Harrison, G. A.

    1974-01-01

    Young Sprague-Dawley rats were exposed to 100% oxygen at 450 mm Hg in constant environment capsules for 90 days. Lung tissue examined by electron microscopy revealed a number of changes, many similar to those observed after exposure to oxygen at 760 mm Hg for shorter periods of time. Alterations in vesicle size and number and in mitochondrial matrix and cristae appear in both the endothelial and epithelial cells. Blebbing and rarefication of cytoplasm occur in both cell layers of the alveolo-capillary wall. Also seen are fluid in the basement membrane, platelets in the capillaries, and alveolar fluid and debris. All of these alterations occur at 1 atm exposure. However, after exposure to 450 mm Hg the changes are not as widespread nor as destructive as they are at the higher pressure.

  2. Ejector/liquid ring pump provides <0. 30 mm Hg vacuum for polymerization vessel

    SciTech Connect

    Lockwood, A.; Gaines, A.

    1982-03-01

    Firestone Fibers and Textiles Company, a division of Firestone Tire and Rubber Company, manufactures tire and industrial yarns of polyester and nylon-6. Nylon-6 molding and extrusion resins are also produced at the plant in Hopewell, Virginia. The process for making polyester requires an extremely low vacuum on the polymerization reactor. A consistent polymerization vessel vacuum of 0.3 mm Hg is needed, but the existing vacuum source, a five-stage steam jet ejector, could only provide a 0.5 mm Hg level. Two options were considered when the company decided to replace the original system with a system designed for 0.15 mm Hg with a non-condensible gas load of 10.8 lb/hr. A new five-stage jet ejector system to meet these requirements would use 1395 lb/hr of 100 psig steam. The other option was a hybrid vacuum source composed of a three-stage steam ejector system and a liquid ring vacuum pump that is more energy efficient than ejectors for low vacuum applications. The hybrid system was selected because the three-stage jet ejector would use only 1240 lb/hr of 100 psig steam. The liquid ring vacuum pump would increase the material and installation cost of the system by about $4000, but the savings in steam consumption would pay back the added cost in less than two years. The jet ejector/liquid ring vacuum pump system has provided both the capacity and the extremely low vacuum needed for the polyester polymerization vessel, after making a small modification. The hybrid vacuum source is reliable, requires only routine maintenance, and will contiue to save substantial amounts of steam each year compared to the five-stage steam jet ejector.

  3. [What happens when mmHg are replaced by kPa? (author's transl)].

    PubMed

    Stepanik, J

    1981-12-01

    Resolution no. 30.39 of the WHA, passed in May 1977, recommends the adoption of SI units by the medical community throughout the world, including a change from mmHg to kPa. In Austria this requirement has been law since January 1978. This paper describes how simply the transition can be made and how other results, such as those of tonography and differential tonometry, are numerically altered as a result. Finally a simple modification is described which enables the Goldmann tonometer to indicate intraocular pressure, its kPa being equal to g on the scale.

  4. Effects of exposing rats to 100% oxygen at 450 and 600 mm Hg on in vitro liver and adipose tissue lipid synthesis.

    NASA Technical Reports Server (NTRS)

    Feller, D. D.; Neville, E. D.; Talarico, K. S.

    1972-01-01

    Male rats (260-285 gm) were exposed to 100% oxygen at 450 or 600 mm Hg for 1 to 4 days. Rats maintained at 450 mm Hg ate 92% the amount of food eaten by ad libitum controls maintained at sea level conditions. At 600 mm Hg, the food intake was 77% of the ad libitum controls. No difference was found in the plasma level of glucose, free fatty acids, and corticosterone between oxygen exposed rats and their respective pair-fed controls. The in vitro conversion of acetate into fatty acids by adipose tissue from rats exposed at 450 mm Hg for 2, 3, or 4 days was significantly increased above pair-fed controls and ad libitum controls. Increasing the oxygen pressure to 600 mm Hg abolished this increase, and in fact, reversed the increased synthesis to a significant decrease for the 4-day exposure.

  5. Characterization of the 80-mm diameter Hamamatsu PMTs for the KM3NeT project

    SciTech Connect

    Aiello, S.; Giordano, V.; Leonora, E.; Classen, L.; Reubelt, J.; Peek, H.; Visser, E.; Samtleben, D.; Kalekin, Oleg Collaboration: KM3NeT Collaboration

    2014-11-18

    The optical module designed for the KM3NeT project consists of 31 photomultipliers of 3-inch diameter housed into a 17-inch diameter glass sphere. A proposed photomultiplier was the R12199-02 Hamamatsu 80-mm diameter. 203 of such PMTs have been delivered from Hamamatsu and tested by the KM3NeT groups of NIKHEF-Amsterdam, ECAP-Erlangen and INFN-Catania. Tests have been performed to measure the main parameters, such as gain, transit time spread, dark pulses rate, fraction of spurious pulses, quantum efficiency and effective photocathode size. The main results matched with the requirements of the project. Methods and results are presented in this report.

  6. How to explain a PaO2 of 140 mmHg in a venous line?

    PubMed

    Mizzi, Anna; Landoni, Giovanni; Corno, Laura; Fichera, Mariano; Nuzzi, Massimiliano; Zangrillo, Alberto

    2009-01-01

    Metformin is a commonly used oral antidiabetic drug which can cause lactic acidosis. Although rare, this condition carries a high mortality risk. Correction of metabolic acidaemia is essential for treatment and dialysis with bicarbonate replacement is the gold standard approach. A 53-year-old man with diabetes on metformin therapy was admitted to the intensive care unit with severe lactic acidosis and acute renal failure suggesting metformin intoxication. The lactic acidosis was treated with bicarbonate haemodialysis and his pH normalized after 10 hours, but he died because of myocardial infarction due to severe hypotension. At ICU admission an aortic dissection was also hypothesized but TEE did not evidence aortic dissection. The dilemma in this patient was represented by the abnormal PaO2 value (140 mmHg) in the venous blood gas analysis. Considering that metformin acts on mitochondrial respiration, the dilemma may be explained by hypothesizing a cellular respiration block caused by metformin or severe acidosis. (www.actabiomedica.it)

  7. The electrical properties of Hg-sensitized ``photox''-oxide layers deposited at 80°C

    NASA Astrophysics Data System (ADS)

    Shacham-Diamand, Y.; Chuh, T.; Oldham, W. G.

    1987-02-01

    This paper deals with the electrical properties of low-pressure CVD SiO 2 deposited at 80°C. The deposition rate is enhanced by UV radiation in the presence of Hg vapor. The photo-enhanced low-pressure chemical-vapor-deposited oxide, known also as "photox," offers a good quality oxide deposited at temperatures as low as 80°C. The films are deposited in a batch-load "photox" barrel reactor and subsequently annealed at 950°C for 30 min in a conventional hot-wall furnace. Cold-sputtered aluminum-gate guard-ring capacitors are fabricated on the oxide films. High-frequency and quasi-static capacitance measurements indicate the interfacial properties of "photox" are comparable to those of thermal oxide. Fast interface states density are less than 2 × 10 10 cm -2 eV -1 and a light negative interfacial charge could just be detected. The dielectric breakdown field is typically 4-5 MV/cm. Deep-depletion transient-capacitance measurements were performed at temperatures between 20 and 100°C to investigate the possible impact of "photox" processing on the generation lifetime. The Hg in particular might be suspected as a heavy-metal contaminant. Typical recovery times observed at 20°C were in the range of 10-15 min. The generation lifetime derived from such measurements ranges from 140 to 200 μs which is comparable to values for control samples made with standard thermal oxide. The magnitude and temperature dependence of the generation lifetime suggest that the same G-R centers are present in both "photox" and thermal oxide devices. The only apparent electrical effect of the Hg vapors used in the deposition process is a small negative fixed interface charge, 2 × 10 10cm-2.

  8. The effectiveness of pressure therapy (15–25 mmHg) for hypertrophic burn scars: A systematic review and meta-analysis

    PubMed Central

    Ai, Jin-Wei; Liu, Jiang-tao; Pei, Sheng-Duo; Liu, Yu; Li, De-Sheng; Lin, Hong-ming; Pei, Bin

    2017-01-01

    Although pressure therapy (PT) represents the standard care for prevention and treatment of hypertrophic scar (HS) from burns, its practice is largely based on empirical evidence and its effectiveness remains controversial. To clarify the effect of PT (15–25 mmHg) for HS, we performed the systematic review and meta-analysis. Several electronic databases were screened to identify related randomized controlled trials (RCTs). 12 RCTs involving 710 patients with 761 HS resulting from burn injuries were included. Compared with non/low-PT, cases treated with PT (15–25 mmHg) showed significant differences in Vancouver Scar Scale score (MD = −0.58, 95% CI = −0.78–−0.37), thickness (SMD = −0.25, 95% CI = −0.40–−0.11), brightness (MD = 2.00, 95% CI = 0.59–3.42), redness (MD = −0.79, 95% CI = −1.52–−0.07), pigmentation (MD = −0.16, 95% CI = −0.32–−0.00) and hardness (SMD = −0.65, 95% CI = −1.07–−0.23). However, there was no difference in vascularity (MD = 0.03, 95% CI = −0.43–0.48). Our analysis indicated that patients with HS who were managed with PT (15–25 mmHg) showed significant improvements. Due to limitations, more large and well-designed studies are needed to confirm our findings and the side-effects of the PT may also need to be evaluated. PMID:28054644

  9. Oral corticosteroids can improve nocturnal isolated hypoxemia in stable COPD patients with diurnal PaO2 > 60 mmHg.

    PubMed

    Sposato, B; Mariotta, S; Palmiero, G; Ricci, A; Gencarelli, G; Franco, C

    2007-01-01

    The aim of this study was to evaluate whether a short therapy cycle of oral methylprednisolone plus conventional therapy might improve isolated nocturnal hypoxemia evidenced through pulse-oxymetry in 28 patients (19 M/9 F; mean age 71 +/- 8.31) with stable moderate to severe COPD (average FEV1 of 43.33 +/- 9.38 of theoretical) and daytime PaO2 > 60 mmHg. All patients showed oxygen desaturation during the night and apnoea/hypoapnoea index < or = 10, measured by means of a nocturnal polysomnography and were successfully on conventional treatment for COPD. The patients were randomly divided into two groups: 14 (steroid group) were administered methylprednisolone for three weeks at progressively decreasing doses (16 mg/die for the first 7 days, then 8 mg die for another 7 days, and finally 4 mg die for another 7 days) plus conventional therapy (bronchodilators and inhaled corticosteroids). The remaining 14 patients (control group) instead were on conventional therapy only. After 3 weeks for the steroid group, but no for the control group, was improved next parameters (p < 0.0001): VC (L) dropped from 2.53 +/- 0.85 measured at baseline to 2.82 +/- 0.84, FEV1 dropped from 1.07 +/- 0.31 L to 1.23 +/- 0.31 L, the IC dropped from 1.71 +/- 0.48 to 2 +/- 0.37 L, the average nocturnal SpO2% from 90.4 +/- 1.79 to 92.3 +/- 1.72 and the Nocturnal Time % of SpO2 < 90% went from 31.19 +/- 18.12 to 10.88 +/- 11.56 after 3 weeks of therapy. Also dyspnoea, sleep duration and mean heart rate significantly improved (p < 0.0001). There was also a significant correlation between average increase in mean nocturnal SpO2% and in Lowest SpO2% and the variation in inspiratory capacity (IC) and in Sleep Duration % in the steroid group (p < 0.0001). In conclusion, methylprednisolone in combination with conventional medical therapy not only improved lung function values but also mean nocturnal oxyhemoglobin saturation and sleep duration in clinically stabilized COPD patients who experience

  10. Environmental impact of CO2, Rn, Hg degassing from the rupture zones produced by Wenchuan M s 8.0 earthquake in western Sichuan, China.

    PubMed

    Zhou, Xiaocheng; Chen, Zhi; Cui, Yueju

    2016-10-01

    The concentrations and flux of CO2, (222)Radon (Rn), and gaseous elemental mercury (Hg) in soil gas were investigated based on the field measurements in June 2010 at ten sites along the seismic rupture zones produced by the May 12, 2008, Wenchuan M s 8.0 earthquake in order to assess the environmental impact of degassing of CO2, Rn and Hg. Soil gas concentrations of 344 sampling points were obtained. Seventy measurements of CO2, Rn and Hg flux by the static accumulation chamber method were performed. The results of risk assessment of CO2, Rn and Hg concentration in soil gas showed that (1) the concentration of CO2 in the epicenter of Wenchuan M s 8.0 earthquake and north end of seismic ruptures had low risk of asphyxia; (2) the concentrations of Rn in the north segment of seismic ruptures had high levels of radon, Maximum was up to level 4, according to Chinese code (GB 50325-2001); (3) the average geoaccumulation index I geo of soil Hg denoted the lack of soil contamination, and maximum values classified the soil gas as moderately to strongly polluted in the epicenter. The investigation of soil gas CO2, Rn and Hg degassing rate indicated that (1) the CO2 in soil gas was characterized by a mean [Formula: see text] of -20.4 ‰ and by a mean CO2 flux of 88.1 g m(-2) day(-1), which were in the range of the typical values for biologic CO2 degassing. The maximum of soil CO2 flux reached values of 399 g m(-2) day(-1) in the epicenter; (2) the soil Rn had higher exhalation in the north segment of seismic ruptures, the maximum reached value of 1976 m Bq m(-2) s(-1); (3) the soil Hg flux was lower, ranging from -2.5 to 18.7 n g m(-2) h(-1) and increased from south to north. The mean flux over the all profiles was 4.2 n g m(-2) h(-1). The total output of CO2 and Hg degassing estimated along seismic ruptures for a survey area of 18.17 km(2) were approximately 0.57 Mt year(-1) and 688.19 g year(-1). It is recommended that land-use planners should

  11. Atomic radii for atoms with the 6s shell outermost: The effective atomic radius and the van der Waals radius from {sub 55}Cs to {sub 80}Hg

    SciTech Connect

    Tatewaki, Hiroshi; Hatano, Yasuyo; Noro, Takeshi; Yamamoto, Shigeyoshi

    2015-06-15

    We consider, for atoms from {sub 55}Cs to {sub 80}Hg, the effective atomic radius (r{sub ear}), which is defined as the distance from the nucleus at which the magnitude of the electric field is equal to that in He at one half of the equilibrium bond length of He{sub 2}. The values of r{sub ear} are about 50% larger than the mean radius of the outermost occupied orbital of 6s, . The value of r{sub ear} decreases from {sub 55}Cs to {sub 56}Ba and undergoes increases and decreases with rising nuclear charge from {sub 57}La to {sub 70}Y b. In fact r{sub ear} is understood as comprising two interlaced sequences; one consists of {sub 57}La, {sub 58}Ce, and {sub 64}Gd, which have electronic configuration (4f{sup n−1})(5d{sup 1})(6s{sup 2}), and the remaining atoms have configuration (4f{sup n})(6s{sup 2}). The sphere defined by r{sub ear} contains 85%–90% of the 6s electrons. From {sub 71}Lu to {sub 80}Hg the radius r{sub ear} also involves two sequences, corresponding to the two configurations 5d{sup n+1}6s{sup 1} and 5d{sup n}6s{sup 2}. The radius r{sub ear} according to the present methodology is considerably larger than r{sub vdW} obtained by other investigators, some of who have found values of r{sub vdW} close to .

  12. Formation of Hg(II) tetrathiolate complexes with cysteine at neutral pH

    SciTech Connect

    Warner, Thomas; Jalilehvand, Farideh

    2016-01-04

    Mercury(II) ions precipitate from aqueous cysteine (H2Cys) solutions containing H2Cys/Hg(II) mole ratio ≥ 2.0 as Hg(S-HCys)2. In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg(S,N-Cys)2]2- complex dominating. With excess cysteine (H2Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg(S-Cys)4]6- complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which CHg(II) varied between 8 – 9 mM and 80 – 100 mM, respectively, with H2Cys/Hg(II) mole ratios from 4 to ~20. The solutions were prepared in the pH range 7.1 – 8.8, at the pH at which the initial Hg(S-HCys)2 precipitate dissolved. The variations in the Hg(II) speciation were followed by 199Hg NMR, X-ray absorption and Raman spectroscopic techniques. Our results show that in the dilute solutions (CHg(II) = 8 – 9 mM), mixtures of di-, tri- (major) and tetrathiolate complexes exist at moderate cysteine excess (CH2Cys ~ 0.16 M) at pH 7.1. In the more concentrated solutions (CHg(II) = 80 – 100 mM) with high cysteine excess (CH2Cys > 0.9 M), tetrathiolate [Hg(S-cysteinate)4]m-6 (m = 0 – 4) complexes dominate in the pH range 7.3 – 7.8, with lower charge than for the [Hg(S-Cys)4]6- complex due to protonation of some (m) of the amino groups of the coordinated cysteine ligands. In conclusion, the results of this investigation could provide a key to the mechanism of biosorption and accumulation of Hg(II) ions in biological / environmental systems.

  13. Formation of Hg(II) tetrathiolate complexes with cysteine at neutral pH

    DOE PAGES

    Warner, Thomas; Jalilehvand, Farideh

    2016-01-04

    Mercury(II) ions precipitate from aqueous cysteine (H2Cys) solutions containing H2Cys/Hg(II) mole ratio ≥ 2.0 as Hg(S-HCys)2. In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg(S,N-Cys)2]2- complex dominating. With excess cysteine (H2Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg(S-Cys)4]6- complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which CHg(II) varied between 8 – 9 mM and 80 – 100 mM, respectively, with H2Cys/Hg(II)more » mole ratios from 4 to ~20. The solutions were prepared in the pH range 7.1 – 8.8, at the pH at which the initial Hg(S-HCys)2 precipitate dissolved. The variations in the Hg(II) speciation were followed by 199Hg NMR, X-ray absorption and Raman spectroscopic techniques. Our results show that in the dilute solutions (CHg(II) = 8 – 9 mM), mixtures of di-, tri- (major) and tetrathiolate complexes exist at moderate cysteine excess (CH2Cys ~ 0.16 M) at pH 7.1. In the more concentrated solutions (CHg(II) = 80 – 100 mM) with high cysteine excess (CH2Cys > 0.9 M), tetrathiolate [Hg(S-cysteinate)4]m-6 (m = 0 – 4) complexes dominate in the pH range 7.3 – 7.8, with lower charge than for the [Hg(S-Cys)4]6- complex due to protonation of some (m) of the amino groups of the coordinated cysteine ligands. In conclusion, the results of this investigation could provide a key to the mechanism of biosorption and accumulation of Hg(II) ions in biological / environmental systems.« less

  14. Comparison of acoustic data from a 102 mm conic nozzle as measured in the RAE 24-foot wind tunnel and the NASA Ames 40- by 80-foot wind tunnel

    NASA Technical Reports Server (NTRS)

    Atencio, A., Jr.; Mckie, J.

    1982-01-01

    A cooperative program between the Royal Aircraft Establishment (RAE), England, and the NASA Ames Research Center was initiated to compare acoustic measurements made in the RAE 24-foot wind tunnel and in the Ames 40- by 80-foot wind tunnel. The acoustic measurements were made in both facilities using the same 102 mm conical nozzle supplied by the RAE. The nozzle was tested by each organization using its respective jet test rig. The mounting hardware and nozzle exit conditions were matched as closely as possible. The data from each wind tunnel were independently analyzed by the respective organization. The results from these tests show good agreement. In both facilities, interference with acoustic measurement is evident at angles in the forward quadrant.

  15. Effect of carboxylic and thiol ligands (oxalate, cysteine) on the kinetics of desorption of Hg(II) from kaolinite

    SciTech Connect

    Senevirathna, W. U.; Zhang, Hong; Gu, Baohua

    2010-01-01

    Sorption and desorption of Hg(II) on clay minerals can impact the biogeochemical cycle and bio-uptake of Hg in the environment. We studied the kinetics of the desorption of Hg(II) from kaolinite as affected by oxalate and cysteine, representing the ligands with carboxylic and thiol groups of different affinities for Hg(II). The effects of pH (3, 5, and 7), ligand concentration (0.25 and 1.0 mM), and temperature (15 C, 25 C, and 35 C) on the Hg(II) desorption were investigated through desorption kinetics. Our study showed that the Hg(II) desorption was pH dependent. In the absence of any organic ligand, >90% of the previously adsorbed Hg(II) desorbed at pH 3 within 2 h, compared to <10% at pH 7. Similar results were observed in the presence of oxalate, showing that it hardly affected the Hg(II) desorption. Cysteine inhibited the Hg(II) desorption significantly at all the pH tested, especially in the first 80 min with the desorption less than 20%, but the inhibition of the desorption appeared to be less prominent afterwards. The effect of the ligand concentration on the Hg(II) desorption was small, especially in the presence of oxalate. The effect of temperature on the Hg(II) desorption was nearly insignificant. The effect of the organic acids on the Hg(II) sorption and desorption is explained by the formation of the ternary surface complexes involving the mineral, ligand, and Hg(II). The competition for Hg(II) between the cysteine molecules adsorbed on the particle surfaces and in the solution phase probably can also affect the Hg(II) desorption.

  16. Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation

    SciTech Connect

    Luo, Hong-Wei; Yin, Xiangping; Jubb, Aaron M.; Chen, Hongmei; Lu, Xia; Zhang, Weihua; Lin, Hui; Yu, Han-Qing; Liang, Liyuan; Sheng, Guo-Ping; Gu, Baohua

    2016-11-09

    Atmospheric deposition of mercury (Hg) to surface water is one of the dominant sources of Hg in aquatic environments and ultimately drives methylmercury (MeHg) toxin accumulation in fish. It is known that freshly deposited Hg is more readily methylated by microorganisms than aged or preexisting Hg; however the underlying mechanism of this process is unclear. Here we report that Hg bioavailability is decreased by photochemical reactions between Hg and dissolved organic matter (DOM) in water. Photo-irradiation of Hg-DOM complexes results in loss of Sn(II)-reducible (i.e. reactive) Hg and up to an 80% decrease in MeHg production by the methylating bacterium Geobacter sulfurreducens PCA. Loss of reactive Hg proceeded at a faster rate with a decrease in the Hg to DOM ratio and is attributed to the possible formation of mercury sulfide (HgS). Lastly, these results suggest a new pathway of abiotic photochemical formation of HgS in surface water and provide a mechanism whereby freshly deposited Hg is readily methylated but, over time, progressively becomes less available for microbial uptake and methylation.

  17. Photochemical reactions between mercury (Hg) and dissolved organic matter decrease Hg bioavailability and methylation

    DOE PAGES

    Luo, Hong-Wei; Yin, Xiangping; Jubb, Aaron M.; ...

    2016-11-09

    Atmospheric deposition of mercury (Hg) to surface water is one of the dominant sources of Hg in aquatic environments and ultimately drives methylmercury (MeHg) toxin accumulation in fish. It is known that freshly deposited Hg is more readily methylated by microorganisms than aged or preexisting Hg; however the underlying mechanism of this process is unclear. Here we report that Hg bioavailability is decreased by photochemical reactions between Hg and dissolved organic matter (DOM) in water. Photo-irradiation of Hg-DOM complexes results in loss of Sn(II)-reducible (i.e. reactive) Hg and up to an 80% decrease in MeHg production by the methylating bacteriummore » Geobacter sulfurreducens PCA. Loss of reactive Hg proceeded at a faster rate with a decrease in the Hg to DOM ratio and is attributed to the possible formation of mercury sulfide (HgS). Lastly, these results suggest a new pathway of abiotic photochemical formation of HgS in surface water and provide a mechanism whereby freshly deposited Hg is readily methylated but, over time, progressively becomes less available for microbial uptake and methylation.« less

  18. Hypotension Begins at 110 mm Hg: Redefining Hypotension With Data

    DTIC Science & Technology

    2007-08-19

    would have potentially spinal, cardiogenic , tension pneumothoraxes, causes of shock . So we did not specifically isolate or exclude that subset. So...appropriately powered studies of hemorrhagic shock . Key Words: Hypotension, Shock , Trauma, Base deficit, Systolic blood pres- sure, Mortality. J Trauma...LeDran in 1743 from his reflection of experiences treating gunshot wounds.1 In 1872, Gross defined the shock state as “a manifestation of the rude

  19. Binding of Hg by bacterial extracellular polysaccharide: a possible role in Hg tolerance.

    PubMed

    Cruz, Kimberly; Guézennec, Jean; Barkay, Tamar

    2017-04-10

    Bacteria employ adaptive mechanisms of mercury (Hg) tolerance to survive in environments containing elevated Hg concentrations. The potential of extracellular polysaccharides (EPS) production by bacteria as a mechanism of Hg tolerance has not been previously investigated. The objectives of this study were to determine if bacterial EPS sorb Hg, and if so does sorption provide protection against Hg toxicity. Purified EPS with different chemical compositions produced by bacterial isolates from microbial mats in French Polynesian atolls and deep-sea hydrothermal vents were assessed for Hg sorption. The data showed that EPS sorbed up to 82% of Hg from solution, that this sorption was dependent on EPS composition, and that sorption was a saturable mechanism. Hg uptake capacities ranged from 0.005 to 0.454 mmol Hg/g for the different EPS. To determine if EPS production could alter bacterial Hg tolerance, Escherichia coli K-12 strains and their EPS defective mutants were tested by the disc inhibition assay. Mercury inhibited growth in a dose-dependent manner with wild-type strains having smaller (~1 mm), but statistically significant, zones of inhibition than various mutants and this difference was related to a 2-fold decline in the amount of EPS produced by the mutants relative to cell biomass. These experiments identified colanic acid and hexosamine as Hg-binding moieties in EPS. Together these data indicate that binding of Hg to EPS affords a low level of resistance to the producing bacteria.

  20. Hyperemesis Gravidarum (HG)

    MedlinePlus

    ... Support Forums BlogHER Research Contact Us Understanding Hyperemesis Theories Diagnosis Treatments Risks Complications Impact Take a Poll ... to and worsen ongoing nausea. There are numerous theories regarding the etiology of hyperemesis gravidarum. Unfortunately, HG ...

  1. The age and mass of the α Herculis triple-star system from a mesa grid of rotating stars with 1.3 ≤ M/M {sub ☉} ≤ 8.0

    SciTech Connect

    Moravveji, Ehsan; Khosroshahi, Habib; Guinan, Edward F.; Wasatonic, Rick

    2013-12-01

    α{sup 1} Her is the second closest asymptotic giant branch (AGB) star to the Sun, and the variable luminous M5 Ib-II member of a triple-stellar system containing G8 III and A9 IV-V components. However, the mass of this important star was previously uncertain, with published values ranging from ∼2-15 M {sub ☉}. As shown by this study, its fortuitous membership in a nearby resolved triple-star system makes it possible to determine its fundamental properties including its mass and age. We present over 20 years of VRI photometry of α{sup 1} Her as well as Wing intermediate-band near-IR TiO and NIR continuum photometry. We introduce a new photometry-based calibration technique and extract the effective temperature and luminosity of α{sup 1} Her, in agreement with recent interferometric measures. We find average values of T {sub eff} = 3280 ± 87 K and log (L/L {sub ☉}) = 3.92 ± 0.14. With the MESA code, we calculate a dense grid of evolutionary tracks for Galactic low- to intermediate-mass (1.3 to 8 M {sub ☉}) rotating stars from the pre-main sequence phase to the advanced AGB phase. We include atomic diffusion and rotation mechanisms to treat the effects of extra elemental mixing. Based on the observed properties of the α Herculis stars, we constrain the age of the system to lie in the range 0.41 to 1.25 Gyr. Thus, the mass of α{sup 1} Her lies in the range 2.175 ≤ M/M {sub ☉} ≤ 3.250. We compare our model-based age inference with recent tracks of the Geneva and STAREVOL codes, and show their agreement. In the prescribed mass range for α{sup 1} Her, the observed {sup 12}C/{sup 13}C and {sup 16}O/{sup 17}O ratios are consistent (within 2σ) with the ratios predicted by the MESA, Geneva, and STAREVOL codes.

  2. Quasiparticle excitations in superdeformed {sup 192}Hg

    SciTech Connect

    Lauritsen, T.; Carpenter, M.P.; Janssens, R.V.F.

    1995-08-01

    The nucleus {sup 192}Hg plays a pivotal role for superdeformation in the mass 190 region, since calculations of single-particle levels show large shell-gaps for the superdeformed (SD) shape at N = 112 and Z = 80. As a result, {sup 192}Hg is referred to as the doubly magic SD nucleus for the A = 190 region. In previous studies, only one superdeformed band was observed in this nucleus, and this fact was cited as indirect evidence that large shell gaps do indeed exist at the proposed particle numbers.

  3. Methylmercury (MeHg)

    Integrated Risk Information System (IRIS)

    Methylmercury ( MeHg ) ; CASRN 22967 - 92 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  4. Status of LWIR HgCdTe infrared detector technology

    NASA Technical Reports Server (NTRS)

    Reine, M. B.

    1990-01-01

    The performance requirements that today's advanced Long Wavelength Infrared (LWIR) focal plane arrays place on the HgCdTe photovoltaic detector array are summarized. The theoretical performance limits for intrinsic LWIR HgCdTe detectors are reviewed as functions of cutoff wavelength and operating temperature. The status of LWIR HgCdTe photovoltaic detectors is reviewed and compared to the focal plane array (FPA) requirements and to the theoretical limits. Emphasis is placed on recent data for two-layer HgCdTe PLE heterojunction photodiodes grown at Loral with cutoff wavelengths ranging between 10 and 19 microns at temperatures of 70 to 80 K. Development trends in LWIR HgCdTe detector technology are outlined, and conclusions are drawn about the ability for photovoltaic HgCdTe detector arrays to satisfy a wide variety of advanced FPA array applications.

  5. Hg(+) Frequency Standards

    NASA Technical Reports Server (NTRS)

    Prestage, John D.; Tjoelker, Robert L.; Maleki, Lute

    2000-01-01

    In this paper we review the development of Hg(+) microwave frequency standards for use in high reliability and continuous operation applications. In recent work we have demonstrated short-term frequency stability of 3 x 10(exp -14)/nu(sub tau) when a cryogenic oscillator of stability 2-3 x 10(exp 15) was used a the local oscillator. The trapped ion frequency standard employs a Hg-202 discharge lamp to optically pump the trapped Hg(+)-199 clock ions and a helium buffer gas to cool the ions to near room temperature. We describe a small Hg(+) ion trap based frequency standard with an extended linear ion trap (LITE) architecture which separates the optical state selection region from the clock resonance region. This separation allows the use of novel trap configurations in the resonance region since no optical pumping is carried out there. A method for measuring the size of an ion cloud inside a linear trap with a 12-rod trap is currently being investigated. At approx. 10(exp -12), the 2nd order Doppler shift for trapped mercury ion frequency standards is one of the largest frequency offsets and its measurement to the 1% level would represent an advance in insuring the very long-term stability of these standards to the 10(exp -14) or better level. Finally, we describe atomic clock comparison experiments that can probe for a time variation of the fine structure constant, alpha = e(exp 2)/2(pi)hc, at the level of 10(exp -20)/year as predicted in some Grand Unified String Theories.

  6. Methylation of Hg downstream from the Bonanza Hg mine, Oregon

    USGS Publications Warehouse

    Gray, John E.; Hines, Mark E.; Krabbenhoft, David P.; Thoms, Bryn

    2012-01-01

    Speciation of Hg and conversion to methyl-Hg were evaluated in stream sediment, stream water, and aquatic snails collected downstream from the Bonanza Hg mine, Oregon. Total production from the Bonanza mine was >1360t of Hg, during mining from the late 1800s to 1960, ranking it as an intermediate sized Hg mine on an international scale. The primary objective of this study was to evaluate the distribution, transport, and methylation of Hg downstream from a Hg mine in a coastal temperate climatic zone. Data shown here for methyl-Hg, a neurotoxin hazardous to humans, are the first reported for sediment and water from this area. Stream sediment collected from Foster Creek flowing downstream from the Bonanza mine contained elevated Hg concentrations that ranged from 590 to 71,000ng/g, all of which (except the most distal sample) exceeded the probable effect concentration (PEC) of 1060ng/g, the Hg concentration above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in stream sediment collected from Foster Creek varied from 11 to 62ng/g and were highly elevated compared to regional baseline concentrations (0.11-0.82ng/g) established in this study. Methyl-Hg concentrations in stream sediment collected in this study showed a significant correlation with total organic C (TOC, R2=0.62), generally indicating increased methyl-Hg formation with increasing TOC in sediment. Isotopic-tracer methods indicated that several samples of Foster Creek sediment exhibited high rates of Hg-methylation. Concentrations of Hg in water collected downstream from the mine varied from 17 to 270ng/L and were also elevated compared to baselines, but all were below the 770ng/L Hg standard recommended by the USEPA to protect against chronic effects to aquatic wildlife. Concentrations of methyl-Hg in the water collected from Foster Creek ranged from 0.17 to 1.8ng/L, which were elevated compared to regional baseline sites upstream and downstream

  7. Hg2+ reduction and re-emission from simulated wet flue gas desulfurization liquors.

    PubMed

    Wo, Jingjing; Zhang, Meng; Cheng, Xiaoya; Zhong, Xiaohang; Xu, Jiang; Xu, Xinhua

    2009-12-30

    In this study, considering that Hg(2+) in wet flue gas desulfurization (FGD) systems can easily be reduced and then released into atmosphere, causing secondary pollution, the researches about Hg(2+) reduction and Hg(0) re-emission mechanism were carried out. The effects of several experimental parameters on the reduction were studied, including initial pH, temperature, and concentrations of Cl(-) and S(IV). Our experimental results indicated that Cl(-) had a restraining effect on the Hg(2+) reduction and Hg(0) re-emission, after 24h reaction, only 20.5% of Hg(2+) was reduced with 100mM Cl(-) in simulated desulfurization solution. Cl(-) can slow Hg(2+) reduction and Hg(0) re-emissions dramatically through changing reaction mechanism, with formation of new intermediate: ClHgSO(3)(-), which can decompose to Hg(0), but much more slowly than Hg(SO(3))(2)(2-) or HgSO(3). Simulating the conditions of the practical application (initial pH 5, T=50 degrees C, S(IV)=5 mM, Cl(-)=100 mM), we also found that Ca(2+), NO(3)(-), F(-), etc. all had obvious effects on reduction rates. Based on the material balance and characteristic of the reactants, the reduction emission mechanism of Hg(2+) has been established, providing theoretical basis for industrial application of mercury control in wet FGD systems.

  8. Decay properties of the new isotopes [sup 172]Hg and [sup 173]Hg

    SciTech Connect

    Seweryniak, D.; Uusitalo, J.; Carpenter, M.P.; Nisius, D.; Davids, C.N.; Brown, L.T.; Henderson, D.J.; Janssens, R.V. ); Seweryniak, D.; Conticchio, L.; Walters, W.B. ); Bingham, C.R.; Wauters, J. ); Woods, P.J. )

    1999-09-01

    The [alpha] decays of the two neutron-deficient nuclei [sup 172]Hg and [sup 173]Hg were observed for the first time using the [sup 78]Kr([sup 96]Ru,2n) and [sup 80]Kr([sup 96]Ru,3n) reactions, respectively. The reaction products were dispersed according to their mass-to-charge state ratios in the Argonne Fragment Mass Analyzer and implanted in a double-sided silicon strip detector, where their subsequent decays were studied using spatial and time correlations between implants and decays. A half-life of 250([sub [minus]90][sup +350]) [mu]s and an energy of 7350(12) keV were deduced for the [alpha] decay of [sup 172]Hg. In [sup 173]Hg the half-life was measured to be 0.93([sub [minus]0.26][sup +0.57]) ms and the corresponding energy is 7211(11) keV. In addition, the half-life and energy of the [alpha] decay of [sup 174]Hg were measured more precisely. The reduced widths deduced for these Hg isotopes indicate that the observed decays correspond to unhindered [Delta]l=0 transitions. The [alpha]-decay [ital Q] values are compared with the values calculated using mass tables by M[umlt o]ller and Nix, and by Liran and Zeldes. The latter mass tables show better agreement with the data. [copyright] [ital 1999] [ital The American Physical Society

  9. Hg-Mask Coronagraph

    NASA Astrophysics Data System (ADS)

    Bourget, P.; Veiga, C. H.; Vieira Martins, R.; Assus, P.; Colas, F.

    In order to optimize the occulting process of a Lyot coronagraph and to provide a high dynamic range imaging, a new kind of occulting disk has been developed at the National Observatory of Rio de Janeiro. A mercury (Hg) drop glued onto an optical window by molecular cohesion and compressed by a pellicle film is used as the occulting disk. The minimum of the superficial tension potential function provides an optical precision (lambda/100) of the toric free surface of the mercury. This process provides a size control for the adaptation to the seeing conditions and to the apparent diameter of a resolved object, and in the case of adaptive optics, to the Airy diameter fraction needed. The occultation is a three dimensional process near the focal plane on the toric free surface that provides an apodization of the occultation. The Hg-Mask coronagraph has been projected for astrometric observations of faint satellites near to Jovian planets and works since 2000 at the 1.6 m telescope of the Pico dos Dias Observatory (OPD - Brazil).

  10. Beryllium abundances in Hg-Mn stars

    SciTech Connect

    Boesgaard, A.M.; Heacox, W.D.; Wolff, S.C.; Borsenberger, J.; Praderie, F.

    1982-08-15

    The Hg-Mn stars show anomalous line strengths of many chemical elements including Be. We have observed the Be ii resonance doublet at lambdalambda 3130, 3131 at 6.7 A mm/sup -1/ in 43 Hg-Mn stars and 10 normal stars in the same temperature range with the coude spectrograph of the 2.24 m University of Hawaii telescope at Mauna Kea. Measured equivalent widths of the two lines and/or the blend of the doublet have been compared with predictions from (1) LTE model atmospheres and (2) non-LTE line formation on non-LTE model atmospheres. (For strong Be ii lines, the LTE calculations result in more Be by factors of 2 to 4 than do the non-LTE calculations.) Overabundances of factors of 20--2 x 10/sup 4/ relative to solar have been found for 75% of the Hg-Mn stars. The 25% with little or no Be are typically among the cooler Hg-Mn stars, but for the stars with Be excesses, there is only marginal evidence for a correlationi of the size of the overabundance and temperature. It is suggested that diffusion driven by radiation pressure is responsible for the observed Be abundance anomalies.

  11. HgCdTe hybrid focal plane

    NASA Astrophysics Data System (ADS)

    Rode, J. P.

    1984-09-01

    Second-generation IR systems, consisting of 2-D mosaics of IR detectors, have been under intense development for the last few years. One of the most successful architectures has been a HgCdTe hybrid focal plane array (FPA), using a Si charge-coupled device (CCD) readout chip interfaced to epitaxial HgCdTe. Detection is made by backside-illuminated photovoltaic detectors with high fill factors and quantum efficiency. The detectors are coupled into the CCD by In bumps which mass bond each detector in the mosaic to a CCD input. Advances have been made in uniform, large area HgCdTe detector material that can be grown with a bandgap from less than 0.1 eV to greater than 1 eV. CCD architectures have been developed with simple, linear inputs and dynamic ranges up to 80 dB. Hybrid FPAs are currently being tested in prototype imaging systems, for detecting thermal differences as well as reflected sunlight in the IR. In the 3-5μm region, these arrays have proven capable of noise-equivalent temperature differences as low as 0.01 K, acquired at a 400 Hz frame rate. In addition to improving current imaging systems, these area arrays allow new system concepts to be brought to fruition.

  12. Synthesis and crystal structures of HgFAsF6, Hg(HF)2(AsF6)2, Hg(HF)(AsF6)2 and Hg(AsF6)(SO3F)

    NASA Astrophysics Data System (ADS)

    Mazej, Zoran; Goreshnik, Evgeny A.

    2015-08-01

    The colourless HgFAsF6 was synthesized by oxidation of Hg2(AsF6)2 with elemental fluorine in anhydrous hydrogen fluoride. It crystallizes in the monoclinic space group P21/c with a=7.0645(3) Å, b=9.9023(3) Å, c=7.8686(3) Å, β=102.960(4)° V=536.43(3) Å3, and Z=4 at 150 K. The structure of HgFAsF6 consists of infinite zig-zag -[Hg-F-Hg]- chains oriented parallel to each other along the b axis and interconected by AsF6 groups. Hg(HF)2(AsF6)2 crystallizes in the triclinic space group P 1 bar with a=5.0781(3) Å, b=6.6907(5) Å, c=7.7135(5) Å, α=84.045(5), β=79.277(5)°, γ=80.612(6), V=253.32(3) Å3, and Z=1 at 150 K. The crystal structure is composed of infinite columns of Hg atoms linked by AsF6 groups. Each pair of adjacent Hg atoms is bridged by two AsF6 groups. The coordination of Hg is completed by two F atoms provided by HF molecules. Hg(HF)(AsF6)2 crystallizes in the monoclinic space group P21/c with a=9.4921(8) Å, b=9.2834(6) Å, c=10.5448(7) Å, β=103.795(7)°, V=902.53(12) Å3, and Z=4 at 150 K and it is isotypic to Cd(HF)(AsF6)2. The new mixed-anion compound Hg(AsF6)(SO3F) crystallizes in the monoclinic space group P21/c with a=5.1975(8) Å, b=18.046(3) Å, c=15.873(5) Å, β=93.614(13)°, V=1485.9(6) Å3, and Z=4 at 200 K. All three oxygen atoms from each SO3F group utilize for bonding with three Hg atoms. The Hg1 (Hg2) atoms are coordinated by two (four) oxygen atoms from two (four) SO3F groups and by six (three) fluorine atoms from AsF6 groups forming on that way tridimensional framework.

  13. The new barium zinc mercurides Ba3ZnHg10 and BaZn0.6Hg3.4 - Synthesis, crystal and electronic structure

    NASA Astrophysics Data System (ADS)

    Schwarz, Michael; Wendorff, Marco; Röhr, Caroline

    2012-12-01

    The title compounds Ba3ZnHg10 and BaZn0.6Hg3.4 were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba3ZnHg10 (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 44 Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl4. The flat pyramids are connected via Hg-Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M-M distances (273-301 pm; CN 9-11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317-348 pm) to their Zn/Hg neighbours. In the structure of BaZn0.6Hg3.4 (cubic, cI320, space group I4bar3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba3ZnHg10, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4×4×4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6)4 with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4)2 dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb3Hg20 applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations relate the two title compounds.

  14. Hg tolerance and biouptake of an isolated pigmentation yeast Rhodotorula mucilaginosa.

    PubMed

    Liu, Bing; Wang, Chaogang; Liu, Danxia; He, Ning; Deng, Xu

    2017-01-01

    A pigmented yeast R1 with strong tolerance to Hg2+ was isolated. Phylogenetic identification based on the analysis of 26S rDNA and ITS revealed R1 is a Rhodotorula mucilaginosa species. R1 was able to grow in the presence of 80 mg/L Hg2+, but the lag phase was much prolonged compared to its growth in the absence of Hg2+. The maximum Hg2+ binding capacity of R1 was 69.9 mg/g, and dead cells could bind 15% more Hg2+ than living cells. Presence of organic substances drastically reduced bioavailability of Hg2+ and subsequently decreased Hg2+ removal ratio from aqueous solution, but this adverse effect could be remarkably alleviated by the simultaneous process of cell propagation and Hg2+ biouptake with actively growing R1. Furthermore, among the functional groups involved in Hg2+ binding, carboxyl group contributed the most, followed by amino & hydroxyl group and phosphate group. XPS analysis disclosed the mercury species bound on yeast cells was HgCl2 rather than HgO or Hg0.

  15. Hg tolerance and biouptake of an isolated pigmentation yeast Rhodotorula mucilaginosa

    PubMed Central

    Liu, Bing; Wang, Chaogang; Liu, Danxia; He, Ning; Deng, Xu

    2017-01-01

    A pigmented yeast R1 with strong tolerance to Hg2+ was isolated. Phylogenetic identification based on the analysis of 26S rDNA and ITS revealed R1 is a Rhodotorula mucilaginosa species. R1 was able to grow in the presence of 80 mg/L Hg2+, but the lag phase was much prolonged compared to its growth in the absence of Hg2+. The maximum Hg2+ binding capacity of R1 was 69.9 mg/g, and dead cells could bind 15% more Hg2+ than living cells. Presence of organic substances drastically reduced bioavailability of Hg2+ and subsequently decreased Hg2+ removal ratio from aqueous solution, but this adverse effect could be remarkably alleviated by the simultaneous process of cell propagation and Hg2+ biouptake with actively growing R1. Furthermore, among the functional groups involved in Hg2+ binding, carboxyl group contributed the most, followed by amino & hydroxyl group and phosphate group. XPS analysis disclosed the mercury species bound on yeast cells was HgCl2 rather than HgO or Hg0. PMID:28253367

  16. The Upside to Hg-DOM Associations for Water Quality: Removal of Hg from Solution Using Coagulaion with Metal-Based Salts

    NASA Astrophysics Data System (ADS)

    Henneberry, Y.; Kraus, T. E.; Fleck, J.; Krabbenhoft, D. P.; Horwath, W. R.

    2011-12-01

    This study assessed the potential use of metal-based coagulants to remove dissolved mercury (Hg) from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however those studies used high concentrations of Hg, which did not reflect naturally occurring concentrations of Hg. Filtered water collected from an agricultural drain in the Sacramento-San Joaquin Delta (Delta) was treated with three industrial-grade coagulants (ferric chloride, ferric sulfate, and polyaluminum chloride) to determine their efficacy in removing both inroganic (IHg) and methylmercury (MeHg) from the water column. The Delta suffers from elevated surface water Hg concentrations and as a result is listed as an imparied water body. Coagulants removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant concentrations. Research using isotopically labeled Hg is providing insight into whether coagulation can remove recently added Hg (e.g. atmospheric deposition) from solution and whether once formed, the floc can remove additional Hg from the water column.

  17. Hanawaltite, Hg1+6Hg2+[Cl,(OH)]2O3 - A new mineral from the Clear Creek claim, San Benito County, California: Description and crystal structure

    USGS Publications Warehouse

    Roberts, Andrew C.; Grice, Joel D.; Gault, Robert A.; Criddle, A.J.; Erd, Richard C.

    1996-01-01

    Hanawaltite, ideally Hg1+6Hg2+O3Cl2, is orthorhombic, Pbma (57), with unit-cell parameters refined from powder data: a=11.790(3), b=13.881(4), c=6.450(2) A??, V=1055.7(6) A??3, a:b:c =0.8494:1:0.4647, Z=4. The strongest six lines of the X-ray powder-diffraction pattern [d in A?? (I)(hkl)] are: 5.25 (80)(111), 3.164 (60)(231), 3.053 (100)(041), 2.954 (70)(141), 2.681 (50)(401), and 2.411 (50)(232,341). The mineral is an extremely rare constituent in a small prospect pit near the long-abandoned Clear Creek mercury mine, New Idria district, San Benito County, California. It was found on a single-fracture surface where it is intimately associated with calomel, native mercury, cinnabar, montroydite, and quartz. Individual crystals are subhedral to anhedral, platy to somewhat bladed, and average about 50 ??m in longest dimension. The largest known crystal is approximately 0.3??0.3 mm in size and is striated parallel [001]. Hanawaltite is opaque to translucent (on very thin edges), black to very dark brown-black in color, with a black to dark red-brown streak. Other physical properties include: metallic luster; cleavage {001} good; uneven fracture; brittle; nonfluorescent; H<5; calculated density (for the empirical formula) 9.51 g/cm3. In polished section, hanawaltite is moderately to strongly bireflectant and is pleochroic white (R1) to blue-white (R2). In reflected plane-polarized light, it is white with orange-red internal reflections in very thin grains and at grain margins. The anisotropy is strong with bright metallic blue rotation tints. Measured reflectance values, in air and in oil, are tabulated. Electron-microprobe analysis yielded Hg2O 82.46, HgO 14.27, Cl 3.33, H2O [0.34], sum [100.40], less O=Cl 0.75, total [99.65] wt. %, corresponding to Hg1+6.00H2+1.00[Cl 1.43(OH)0.57]??2.00O3.00, based on O+C1=5. After the crystal structure was determined, the original microprobe value for Hg2O, 96.2, was partitioned in a ratio of 6Hg2O:HgO and (OH) was calculated, such

  18. Identifying the sources and processes of mercury in subtropical estuarine and ocean sediments using Hg isotopic composition.

    PubMed

    Yin, Runsheng; Feng, Xinbin; Chen, Baowei; Zhang, Junjun; Wang, Wenxiong; Li, Xiangdong

    2015-02-03

    The concentrations and isotopic compositions of mercury (Hg) in surface sediments of the Pearl River Estuary (PRE) and the South China Sea (SCS) were analyzed. The data revealed significant differences between the total Hg (THg) in fine-grained sediments collected from the PRE (8-251 μg kg(-1)) and those collected from the SCS (12-83 μg kg(-1)). Large spatial variations in Hg isotopic compositions were observed in the SCS (δ(202)Hg, from -2.82 to -2.10‰; Δ(199)Hg, from +0.21 to +0.45‰) and PRE (δ(202)Hg, from -2.80 to -0.68‰; Δ(199)Hg, from -0.15 to +0.16‰). The large positive Δ(199)Hg in the SCS indicated that a fraction of Hg has undergone Hg(2+) photoreduction processes prior to incorporation into the sediments. The relatively negative Δ(199)Hg values in the PRE indicated that photoreduction of Hg is not the primary route for the removal of Hg from the water column. The riverine input of fine particles played an important role in transporting Hg to the PRE sediments. In the deep ocean bed of the SCS, source-related signatures of Hg isotopes may have been altered by natural geochemical processes (e.g., Hg(2+) photoreduction and preferential adsorption processes). Using Hg isotope compositions, we estimate that river deliveries of Hg from industrial and urban sources and natural soils could be the main inputs of Hg to the PRE. However, the use of Hg isotopes as tracers in source attribution could be limited because of the isotope fractionation by natural processes in the SCS.

  19. Friction, Wear, and Evaporation Rates of Various Materials in Vacuum to 10(exp -7) mm Hg

    NASA Technical Reports Server (NTRS)

    Buckley, Donald H.; Swikert, Max; Johnson, Robert L.

    1961-01-01

    The requirements for bearings and seals to operate in the environment of space dictate a new area for lubrication research. The low ambient pressures encountered in space can be expected to influence the behavior of oil, grease, and solid-film lubricants. The property of these materials most significantly affected by low ambient pressures is the evaporation rate. Various investigators have therefore measured the evaporation rates of oils and greases in vacuum as one method of establishing their relative merit for space applications (1-3). The results of this work have given some indication as to the oils and greases with the greatest stability at reduced ambient pressures. Only limited experimental work, however, has been reported in the literature for inorganic solids and soft metals which have potential use as solid lubricant films or coatings for hard alloy substrates [e.g. Reference ( 4 )]. In general, the evaporation rates of these materials would be lower than those of oils and greases. These films might therefore be very attractive as lubricants for high vacuum service.

  20. Primeval galaxies in the sub-mm and mm

    NASA Technical Reports Server (NTRS)

    Bond, J. Richard; Myers, Steven T.

    1993-01-01

    Although the results of COBE's FIRAS experiment 1 constrain the deviation in energy from the CMB blackbody in the 500-5000 micron range to be delta E/E, sub cmb less than 0.005, primeval galaxies can still lead to a brilliant sub-mm sky of non-Gaussian sources that are detectable at 10 inch resolution from planned arrays such as SCUBA on the James Clerk Maxwell Telescope and, quite plausibly, at sub-arcsecond resolution in planned mm and sub-mm interferometers. Here, we apply our hierarchical peaks method to a CDM model to construct sub-mm and mm maps of bursting PG's appropriate for these instruments with minimum contours chosen to correspond to realistic observational parameters for them and which pass the FIRAS limits.

  1. [Experimental Research of Hg (II) Removal from Aqueous Solutions of HgCl2 with Nano-TiO2].

    PubMed

    Zhou, Xiong; Zhang, Jin-yang; Wang, Ding-yong; Qin, Cai-qing; Xu, Feng; Luo Cheng-zhong; Yang, Xi

    2016-01-15

    Mercury removal from aqueous solutions of HgCl2 was studied by indoor simulation experiments, and the effects of three different diameter of particles of Nano-TiO2 ( Nano-Titanium Dioxide) at different dosage, pH, adsorption time and the initial concentration of Hg2+ on the mercury adsorption from simulated wastewater were investigated. The single factor experiments showed that the optimal conditions were: 7.5 g x L(-1) of 5 nm TiO2 or 2.0 g x L(-1) of 100 nm TiO2, pH 8.0, initial concentration of Hg2+ 15 x mg x L(-1) adsorption time 5 min, and under these conditions the adsorption rates reached 99.5% and 99.3%, relatively. When the content of 25 nm TiO2 was 10 g x L(-1), and the other conditions were pH 8.0, initial concentration of Hg2+ 15 mg x L(-1), adsorption time 60 min, the adsorption rate was 62.8%. The Hg(II) removal effects of the TiO2 particles with different diameters followed the order of 100 nm TiO2 > 5 nm TiO2 > 25 nm TiO2. Component adsorption results showed that the 5 nm TiO2 component adsorption effect was superior to its single adsorption effect, while there was little difference between 100 nm TiO2 component adsorption effect and its single adsorption effect. The results of orthogonal experiments indicated that the influencing factors of the adsorption rate followed the order of pH > the initial concentration of Hg2+ > time > dosage. The optimal experiment scheme was: pH 8.0, a dosage of 100 nm Nano-TiO2 of 2.0 g x L(-1) an initial Hg2+ concentration of 25 mg x L(-1) and adsorption time of 10 min. Under the experimental conditions, the maximum adsorption rate reached 99.9%, at the same time, the equilibrium concentration of Hg(II) was 0.033 mg x L(-1) < 0.05 mg x L(-1), below the current enterprise rules of water pollutants in mercury emissions limits. In addition, the maximum adsorptive capacity was 26.95 mg x g(-1). The adsorption isotherm was in line with the Langmuir isotherm equation, indicating that the Hg(II) uptake by 100 nm Nano-TiO2

  2. Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol-bound Hg.

    PubMed

    Wiederhold, Jan G; Cramer, Christopher J; Daniel, Kelly; Infante, Ivan; Bourdon, Bernard; Kretzschmar, Ruben

    2010-06-01

    Stable Hg isotope ratios provide a new tool to trace environmental Hg cycling. Thiols (-SH) are the dominant Hg-binding groups in natural organic matter. Here, we report experimental and computational results on equilibrium Hg isotope fractionation between dissolved Hg(II) species and thiol-bound Hg. Hg(II) chloride and nitrate solutions were equilibrated in parallel batches with varying amounts of thiol resin resulting in different fractions of thiol-bound and free Hg. Mercury isotope ratios in both fractions were analyzed by multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). Theoretical equilibrium Hg isotope effects by mass-dependent fractionation (MDF) and nuclear volume fractionation (NVF) were calculated for 14 relevant Hg(II) species. The experimental data revealed that thiol-bound Hg was enriched in light Hg isotopes by 0.53 per thousand and 0.62 per thousand (delta(202)Hg) relative to HgCl(2) and Hg(OH)(2), respectively. The computational results were in excellent agreement with the experimental data indicating that a combination of MDF and NVF was responsible for the observed Hg isotope fractionation. Small mass-independent fractionation (MIF) effects (<0.1 per thousand) were observed representing one of the first experimental evidences for MIF of Hg isotopes by NVF. Our results indicate that significant equilibrium Hg isotope fractionation can occur without redox transition, and that NVF must be considered in addition to MDF to explain Hg isotope variations.

  3. Relationship between proline and Hg2+-induced oxidative stress in a tolerant rice mutant.

    PubMed

    Wang, Feijuan; Zeng, Bin; Sun, Zongxiu; Zhu, Cheng

    2009-05-01

    There has been little agreement regarding the mechanism by which proline reduces heavy metal stress. The present work examines the relationship between Hg(2+)-induced oxidative stress and proline accumulation in rice and explores the possible mechanisms through which proline protects against Hg(2+) stress. The effect of proline on alleviation of Hg(2+) toxicity was studied by spectrophotography and enzymatic methods. Hg(2+) induced oxidative stress in rice by increasing lipid peroxidation. Pretreatment of the rice with 2 mM proline for 12 h profoundly alleviated Hg(2+)-induced lipid peroxidation and minimized H(2)O(2) accumulation. Proline pretreatment significantly reduced (p < 0.01) the Hg(2+) content in rice leaves. A comparison of the effects of proline pretreatment on H(2)O(2) accumulation by Hg(2+) and aminotrazole suggested that proline protected cells from Hg(2+)-induced oxidative stress by scavenging reactive oxygen species. The present work demonstrates a protective effect of proline on Hg(2+) toxicity through detoxifying reactive oxygen species, rather than chelating metal ions or maintaining the water balance under Hg(2+) stress.

  4. [Pharmacokinetics and pharmacodynamics of a new 80 mg oral delayed-action isosorbide dinitrate preparation].

    PubMed

    Pello, J Y; Auclert, L; Rey, E; Joly, H; Mialet, C; Puechavy, C; Georges, M; Ruffo, M; Olive, G

    1992-04-01

    A new galenic form of isosorbide dinitrate (consisting of a hydrophilic matrix which allows very slow release of the active drug) was studied from the pharmacokinetic and pharmacodynamic view points in 11 patients with stable angina pectoris under betablocker therapy. After testing their sensitivity to nitrates with a sublingual trinitrin test causing a fall greater than or equal to 20 mmHg in systolic and greater than or equal to 10 mmHg in diastolic blood pressure, the patients were given a single tablet of Risordan LP 80 daily for 7 days. The equilibrium plasma concentrations of isosorbide dinitrate and its mononitrate metabolites (2-isosorbide mononitrate and 5-isosorbide mononitrate) over 24 hours were measured on the 6th treatment day. A method of measuring these nitrate derivatives has been developed and validated. The concentrations measured enabled the study of the pharmacokinetics of this new form, showing an average minimal concentration of 5-isosorbide mononitrate (principal metabolite) of 85 +/- 41 micrograms/l and an amplitude of fluctuation over the 24 hours period of 296 +/- 102 micrograms/l. From the pharmacodynamic point of view, the evaluation of the sensitivity to a single dose of 0.75 mg of trinitrin 24 hours after the first dose of Risordan LP 80, just before the second dose and 24 hours after the seventh dose, showed a significant difference (average decrease of 40 +/- 19 mmHg in systolic blood pressure) with respect to the values observed during the selection phase.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Apollo 17 Index: 70 mm, 35 mm, and 16 mm Photographs

    NASA Technical Reports Server (NTRS)

    Wells, Ronald A. (Compiler)

    1974-01-01

    This index lists and provides supplemental data for all Apollo 17 70 mm, 35 mm, and 16 mm photographs. The 70 mm and 35 mm photographs are indexed in three ways: (1) all photographs are listed in numerical sequence according to NASA photograph number, (2) photographs exposed in lunar orbit are listed according to longitude in 10deg increments, and (3) all photographs exposed on the lunar surface are listed in chronological order. In indexing the 70 mm and 35 mm orbital photographs, individual frames were matched to imagery on the 1:2,750,000 scale Lunar Planning Charts (LOC). Each frame was outlined on the LOC base map, and the principal point determined. The latitude and longitude of each principal point, to the nearest 0.1 degree, is recorded in this index, If the principal point of a photograph is in space or its location obscured by shadow, an approximate longitude was recorded so that the photograph would not be excluded from the computer-generated listing by longitude. Each frame is described in terms of a named lunar surface feature within the boundaries of the frame or, if no named features are within the frame boundaries, a major nearby feature.

  6. Mercury isotope signatures as tracers for Hg cycling at the New Idria Hg mine.

    PubMed

    Wiederhold, Jan G; Smith, Robin S; Siebner, Hagar; Jew, Adam D; Brown, Gordon E; Bourdon, Bernard; Kretzschmar, Ruben

    2013-06-18

    Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) of Hg isotopes provides a new tool for tracing Hg in contaminated environments such as mining sites, which represent major point sources of Hg pollution into surrounding ecosystems. Here, we present Hg isotope ratios of unroasted ore waste, calcine (roasted ore), and poplar leaves collected at a closed Hg mine (New Idria, CA, U.S.A.). Unroasted ore waste was isotopically uniform with δ(202)Hg values from -0.09 to 0.16‰ (± 0.10‰, 2 SD), close to the estimated initial composition of the HgS ore (-0.26‰). In contrast, calcine samples exhibited variable δ(202)Hg values ranging from -1.91‰ to +2.10‰. Small MIF signatures in the calcine were consistent with nuclear volume fractionation of Hg isotopes during or after the roasting process. The poplar leaves exhibited negative MDF (-3.18 to -1.22‰) and small positive MIF values (Δ(199)Hg of 0.02 to 0.21‰). Sequential extractions combined with Hg isotope analysis revealed higher δ(202)Hg values for the more soluble Hg pools in calcines compared with residual HgS phases. Our data provide novel insights into possible in situ transformations of Hg phases and suggest that isotopically heavy secondary Hg phases were formed in the calcine, which will influence the isotope composition of Hg leached from the site.

  7. Photodynamic therapy for Barrett's esophagus using a 20-mm diameter light-delivery balloon

    NASA Astrophysics Data System (ADS)

    Panjehpour, Masoud; Overholt, Bergein F.; Phan, Mary N.; Haydek, John M.; Robinson, Amy R.

    2002-06-01

    Background and Objective: Patients with high grade dysplasia (HGD) in Barrett's esophagus are at a high risk for developing esophageal adenocarcinoma. Esophagectomy is the standard treatment for such patients. The objective of this study was to evaluate the safety and efficacy of photodynamic therapy (PDT) using an improved light delivery balloon for ablation of Barrett's esophagus with high grade dysplasia and/or early cancer. Materials and Methods: 20 patients with HGD or early cancer (19 with HGD, 1 with T1 cancer) received 2 mg/kg of porfimer sodium, intravenously. Two to three days after the injection, laser light was delivered using a cylindrical diffuser inserted inside a 20-mm diameter reflective esophageal PDT balloon. Initially, the balloon was inflated to a pressure of 80 mm Hg. The balloon pressure was gradually reduced to 30 mm Hg. A KTP/dye laser at 630 nm was used as the light source. Light dose of 115 J/cm was delivered at an intensity of 270 mw/cm. Nodules were pre- treated with an extra 50 J/cm using a short diffuser inserted through the scope. Patients were maintained on PPI therapy to keep the gastric pH higher than 4. Eighteen patients required one treatment, while two patients were treated twice. Follow-up consisted of endoscopy with four quadrant biopsies at every 2 cm of the treated area. Thermal ablation was used to treat small residual islands on the follow-ups. The follow-up endoscopies ranged from 6 to 17 months. Results: On follow-up endoscopy, 12 patients had complete replacement of their Barrett's mucosa with neosquamous mucosa. Five patients had residual non-dysplastic Barrett's mucosa, one had indefinite dysplasia, two had low grad dysplasia. There were no residual HGD or cancers. The average length of Barrett's was reduced from 5.4 cm to 1.2 cm. High balloon pressure resulted in wide variation in PDT response among patients. Lower balloon pressures resulted in more consistent destruction of Barrett's mucosa among patients. Five

  8. Apollo 12 photography 70 mm, 16 mm, and 35 mm frame index

    NASA Technical Reports Server (NTRS)

    1970-01-01

    For each 70-mm frame, the index presents information on: (1) the focal length of the camera, (2) the photo scale at the principal point of the frame, (3) the selenographic coordinates at the principal point of the frame, (4) the percentage of forward overlap of the frame, (5) the sun angle (medium, low, high), (6) the quality of the photography, (7) the approximate tilt (minimum and maximum) of the camera, and (8) the direction of tilt. A brief description of each frame is also included. The index to the 16-mm sequence photography includes information concerning the approximate surface coverage of the photographic sequence and a brief description of the principal features shown. A column of remarks is included to indicate: (1) if the sequence is plotted on the photographic index map and (2) the quality of the photography. The pictures taken using the lunar surface closeup stereoscopic camera (35 mm) are also described in this same index format.

  9. Feasibility of a Sustainer Projectile in the 30-mm, 35-mm, and 40-mm Caliber Range

    DTIC Science & Technology

    1980-08-01

    calibers appropriate for air defense. Sustaining the muzzle velocity has the advantage of decreasing the projectile time of flight, thus reducing the...mm Rocket-Assisted Projectiles Air Defense 30 mm 20 A@SrACT I"Centfate an eerseod if VHW en Identify by blocek number) A sustainer projectile is a...feasibility of RAP’s in the smaller calibers appropriate for air defense, * .i.e., the 30-40 nn caliber range. The nominal objective of this study was to

  10. Mercury isotope fractionation during precipitation of metacinnabar (β-HgS) and montroydite (HgO).

    PubMed

    Smith, Robin S; Wiederhold, Jan G; Kretzschmar, Ruben

    2015-04-07

    To utilize stable Hg isotopes as a tracer for Hg cycling and pollution sources in the environment, it is imperative that fractionation factors for important biogeochemical processes involving Hg are determined. Here, we report experimental results on Hg isotope fractionation during precipitation of metacinnabar (β-HgS) and montroydite (HgO). In both systems, we observed mass-dependent enrichments of light Hg isotopes in the precipitates relative to the dissolved Hg. Precipitation of β-HgS appeared to follow equilibrium isotope fractionation with an enrichment factor ε(202)Hg(precipitate-supernatant) of -0.63‰. Precipitation of HgO resulted in kinetic isotope fractionation, which was described by a Rayleigh model with an enrichment factor of -0.32‰. Small mass-independent fractionation was observed in the HgS system, presumably related to nuclear volume fractionation. We propose that Hg isotope fractionation in the HgS system occurred in solution during the transition of O- to S-coordination of Hg(II), consistent with theoretical predictions. In the HgO system, fractionation was presumably caused by the faster precipitation of light Hg isotopes, and no isotopic exchange between solid and solution was observed on the timescale investigated. The results of this work emphasize the importance of Hg solution speciation and suggest that bonding partners of Hg in solution complexes may control the overall isotope fractionation. The determined fractionation factor and mechanistic insights will have implications for the interpretation of Hg isotope signatures and their use as an environmental tracer.

  11. HG ion thruster component testing

    NASA Technical Reports Server (NTRS)

    Mantenieks, M. A.

    1979-01-01

    Cathodes, isolators, and vaporizers are critical components in determining the performance and lifetime of mercury ion thrusters. The results of life tests of several of these components are reported. A 30-cm thruster CIV test in a bell jar has successfully accumulated over 26,000 hours. The cathode has undergone 65 restarts during the life test without requiring any appreciable increases in starting power. Recently, all restarts have been achieved with only the 44 volt keeper supply with no change required in the starting power. Another ongoing 30-cm Hg thruster cathode test has successfully passed the 10,000 hour mark. A solid-insert, 8-cm thruster cathode has accumulated over 4,000 hours of thruster operation. All starts have been achieved without the use of a high voltage ignitor. The results of this test indicate that the solid impregnated insert is a viable neutralizer cathode for the 8-cm thruster.

  12. MCT detectors: from IR to sub-mm and mm wavelength bands

    NASA Astrophysics Data System (ADS)

    Sizov, F. F.; Vasiliev, V. V.; Gumenjuk-Sichevska, J. V.; Kamenev, Yu. E.; Dvoretsky, S. A.; Mikhailov, N. N.

    2008-09-01

    Modern technology advances combined with unique physical properties of mercury cadmium telluride (MCT) material, empower low-signal applications in technical vision systems. Properties of MCT detectors manufactured from LPE and MBE epilayers and their dependences on thickness and doping both for IR and THz regions are discussed. It is shown by comparison of experimental data and modeling of I-V dark current characteristics that MCT photodiode ultimate electrical characteristics are limited by diffusion current in n+-n--p junctions and by current via the deep traps in the gap with position Et= 0.7 Eg above the valence band and concentrations Nt = (1.0-5.5)•1015 cm-3 which are comparable with donor concentration in n--region Nd = (1.1-1.8)•1015 cm-3. Detector array parameters for a wavelength range 8-12 microns are: detectivity D*=1.9•1011 cm•Hz1/2/W, noise equivalent difference temperature NEDT ~ 9 mK, dynamical resistance R ~ 4Â.109 Ohm for the reverse biases ΔV = 0.1-0.2 V. Also, it is shown that MCT layers can be successfully used as sub-mm or mm wave ambient temperature or moderately cooled hot electron bolometers. Thus, in addition to the wavelength range from SWIR to VLIR, where the MCT detectors are employed mainly as photodiodes or photoresistors, they can be used as sub-mm or mm wave detectors in the range from 190 microns to 8 mm. They can be employed here as semiconductor hot electron bolometers (SHEB). Measurements performed at electromagnetic wave frequencies ν = 37, 55, 77 GHz, and also at 0.89 and 1.58 THz with non-optimized Hg0.8Cd0.2Te bolometer prototype, has confirmed the basic concepts of SHEB. At ν = 0.89 THz, 77 GHz and 37 GHz the signal temperature dependencies were measured too. At 77 K the SHEB sensitivity at ν = 37 and 77 GHz is increasing up to two orders compared to room temperature data. The sensitivity Sν ~ 2 V/W at 300 K, and calculated both Johnson-Nyquist and generation-recombination noise values give estimations of

  13. Interface Chemistry of Ternary Semiconductors: Local Morphology of the Hg(1-x)CdxTe-Cr Interface.

    DTIC Science & Technology

    1985-10-15

    a modified Bridgman method. Several oriented (110) posts (3x3x15 " mm3 ) were cut from the center of the cylindrical portion of a boule. Samples cut...levels. Deconvolution of two doublets was performed using the experimental lineshape of the Hg 5d and Cd 4d levels obtained from cleaved HgSe and CdSe ...lineshape of the Hg 5d and Cd 4d levels obtained from cleaved HgSe and CdSe samples. As an example, the result of the decomposition for the clean

  14. New thermal-neutron solid-state electronic detector based on HgI/sub 2/ single crystals

    SciTech Connect

    Melamud, M.; Burshtein, Z.; Levi, A.; Schieber, M.M.

    1983-08-01

    The use of HgI/sub 2/ as a thermal-neutron solid-state electronic detector, in particular its application for neutron diffractometry, is demonstrated for the first time. A single crystal HgI/sub 2/ detector is used to count prompt gamma emissions (0.2--5 MeV) from (n,..gamma..) nuclear reactions in Gd or Cd foils. The neutron counting efficiency depends on the HgI/sub 2/ detector thickness. For a 1-mm thickness of HgI/sub 2/ the efficiency is about 10% compared to the efficiency of a /sup 10/BF/sub 3/ gas detector.

  15. Removal of Hg(II) from aqueous solution using sodium humate as heavy metal capturing agent.

    PubMed

    Wang, Shixiang; Liu, Yong; Fan, Qin; Zhou, Anlan; Fan, Lu; Mu, Yulan

    2016-12-01

    An environmental friendly and economic natural biopolymer-sodium humate (HA-Na) was used to capture Hg(II) from aqueous solutions, and the trapped Hg(II) (HA-Na-Hg) was then removed by aluminium coagulation. The best Hg(II) capturing performance (90.60%) was observed under the following conditions: initial pH of 7.0, coagulation pH of 6.0, HA-Na dosage of 5.0 g L(-1), Al2(SO4)3.18H2O dosage of 4.0 g L(-1), initial Hg(II) concentration of 50 mg L(-1) and capturing time of 30 min. The HA-Na compositions with the molecular weight beyond 70 kDa showed the most intense affinity toward Hg(II). The results showed that the reaction equilibrium was achieved within 10 min (pH 7.0), and could be well fitted by the pseudo-second-order kinetics model. The capturing process could be well described by the Langmuir isotherm model and the maximum capturing capacity of Hg(II) was high up to 9.80 mg g(-1) at 298 K (pH 7.0). The Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that the redox reaction between Hg(II) and HA-Na and the coordination reaction of carboxyl and hydroxy groups of HA-Na with Hg(II) were responsible for Hg(II) removal. The successive regeneration experiment showed that the capturing efficiency of humates for Hg(II) was maintained at about 51% after five capture-regeneration recycles.

  16. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in HG... automatic auxiliary heating equipment, the requirements in part 63 of this subchapter govern and shall...

  17. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in HG... automatic auxiliary heating equipment, the requirements in part 63 of this subchapter govern and shall...

  18. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in HG... automatic auxiliary heating equipment, the requirements in part 63 of this subchapter govern and shall...

  19. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in HG... automatic auxiliary heating equipment, the requirements in part 63 of this subchapter govern and shall...

  20. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in HG... automatic auxiliary heating equipment, the requirements in part 63 of this subchapter govern and shall...

  1. Unique Hg stable isotope signatures of compact fluorescent lamp-sourced Hg.

    PubMed

    Mead, Chris; Lyons, James R; Johnson, Thomas M; Anbar, Ariel D

    2013-03-19

    The recent widespread adoption of compact fluorescent lamps (CFL) has increased their importance as a source of environmental Hg. Stable isotope analysis can identify the sources of environmental Hg, but the isotopic composition of Hg from CFL is not yet known. Results from analyses of CFL with a range of hours of use show that the Hg they contain is isotopically fractionated in a unique pattern during normal CFL operation. This fractionation is large by comparison to other known fractionating processes for Hg and has a distinctive, mass-independent signature, such that CFL Hg could be uniquely identified from other sources. The fractionation process described here may also explain anomalous fractionation of Hg isotopes in precipitation.

  2. Contact Formation (Hg, CD)Te

    DTIC Science & Technology

    1989-12-01

    AD-A21 7 088 0 a CONTACT FORMATION ON (HG, CD )TE FINAL REPORT W.A. BECK AND G.D. DAVIS V C ELECTE , I DECEMBER 1989 JAN22 1990 U.S. ARMY RESEARCH...27709-2211 I N I 11. TITLE (Include Security Clasification) Contact Formation on (Hg, CD )Te (u) 12. PERSONAL AUTHOR(S) W.A. Beck and G.D. Davis 13a...whereas the 1/f noise of the Au contacts originated at th i/" Cd )Te interface or in the underlying (Hg, Cd )Te, the 1/f noise of the Al contacts orig.L

  3. Low-Roughness Plasma Etching of HgCdTe Masked with Patterned Silicon Dioxide

    NASA Astrophysics Data System (ADS)

    Ye, Z. H.; Hu, W. D.; Yin, W. T.; Huang, J.; Lin, C.; Hu, X. N.; Ding, R. J.; Chen, X. S.; Lu, W.; He, L.

    2011-08-01

    A novel mask technique utilizing patterned silicon dioxide films has been exploited to perform mesa etching for device delineation and electrical isolation of HgCdTe third-generation infrared focal-plane arrays (IRFPAs). High-density silicon dioxide films were deposited at temperature of 80°C, and a procedure for patterning and etching of HgCdTe was developed by standard photolithography and wet chemical etching. Scanning electron microscopy (SEM) showed that the surfaces of inductively coupled plasma (ICP) etched samples were quite clean and smooth. Root-mean-square (RMS) roughness characterized by atomic force microscopy (AFM) was less than 1.5 nm. The etching selectivity between a silicon dioxide film and HgCdTe in the samples masked with patterned silicon dioxide films was greater than 30:1. These results show that the new masking technique is readily available and promising for HgCdTe mesa etching.

  4. Effect of additives on Hg2+ reduction and precipitation inhibited by sodium dithiocarbamate in simulated flue gas desulfurization solutions.

    PubMed

    Lu, Rongjie; Hou, Jiaai; Xu, Jiang; Tang, Tingmei; Xu, Xinhua

    2011-11-30

    Mercury (II) (Hg(2+)) ion can be reduced by aqueous S(IV) (sulfite and/or bisulfite) species, which leads to elemental mercury (Hg(0)) emissions in wet flue gas desulfurization (FGD) systems. Numerous reports have demonstrated the high trapping efficiency of sodium dithiocarbamate over heavy metals. In this paper, a novel sodium dithiocarbamate, DTCR, was utilized as a precipitator to control Hg(2+) reduction and Hg(0) emission against S(IV) in FGD solutions. Results indicated that Hg(2+) reduction efficiency decreased dramatically while precipitation rate peaked at around 91.0% in consistence with the increment of DTCR dosage. Initial pH and temperature had great inhibitory effects on Hg(2+) reduction: the Hg(2+) removal rate gradually increased and reached a plateau along with the increment of temperature and initial pH value. Chloride played a key role in Hg(2+) reduction and precipitation reactions. When Cl(-) concentration increased from 0 to 150 mM, Hg(2+) removal rate dropped from 93.84% to 86.05%, and the Hg(2+) reduction rate remained at a low level (<7.8%). SO(4)(2-), NO(3)(-) and other common metal ions would affect the efficiency of Hg(2+) reduction and precipitation reactions in the simulated desulfurization solutions: Hg(2+) removal rate could always be above 90%, while Hg(2+) reduction rate was maintained at below 10%. The predominance of DTCR over aqueous S(IV), indicated by the results above, has wide industrial applications in FGD systems.

  5. Molecular beam photoionization study of HgBr/sub 2/ and HgI/sub 2/

    SciTech Connect

    Linn, S.H.; Tzeng, W.; Brom, J.M. Jr.; Ng, C.Y.

    1983-01-01

    Photoionization efficiency (PIE) data for HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ and their fragment ions have been obtained in the region 600--1350 A using an oven-type supersonic beam source. The ionization energies (IE) for the X /sup 2/Pi/sub 3/2g/ states of HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ were determined to be 10.560 +- 0.003 and 9.5088 +- 0.0022 eV, respectively. The analyses of the Rydberg series converging to the /sup 2/Pi/sub 1/2g/ states of HgBr/sub 2//sup +/ and HgI/sub 2//sup +/ yield a value of 10.8846 +- 0.0012 eV for the IE of the /sup 2/Pi/sub 1/2g/ state of HgBr/sub 2//sup +/ and 10.1953 +- 0.0025 eV for that of HgI/sub 2//sup +/. The major fragment ions from HgBr/sub 2/ were identified to be HgBr/sup +/, Hg/sup +/, Br/sub 2//sup +/, and Br/sup +/ and those from HgI/sub 2/ were found to be HgI/sup +/, I/sub 2//sup +/, and I/sup +/. The measured appearance energies for HgBr/sup +/ and HgI/sup +/ allow the calculation of the bond dissociation energies for HgBr/sup +/ and HgI/sup +/ to be 55 +- 2 and 59 +- 1 kcal/mol, respectively. Similar to the observation in the PIE curves for HgCl/sub 2//sup +/ and its fragment ions, the PIE spectra for HgBr/sub 2//sup +/, HgI/sub 2//sup +/, and their fragment ions are dominated by autoionization structures exhibiting asymmetric Beutler--Fano line profiles. The comparison of the PIE curves of HgCl/sub 2//sup +/, HgBr/sub 2//sup +/, HgI/sub 2//sup +/, and Hg/sup +/ from Hg confirms the previous conclusion that these autoionizing Rydberg series can be assigned to transitions((5d)/sup 10/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/) ..-->.. ((5d)/sup 9/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/ /sup 2/D/sub plus-or-minus5/2/)np and ((5d)/sup 10/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/) ..-->.. ((5d)/sup 9/sigma/sub g//sup 2/sigma/sub u//sup 2/..pi../sub u//sup 4/..pi../sub g//sup 4/ /sup 2/D/sub plus

  6. Optical spectroscopic and reverse-phase HPLC analyses of Hg(II) binding to phytochelatins.

    PubMed Central

    Mehra, R K; Miclat, J; Kodati, V R; Abdullah, R; Hunter, T C; Mulchandani, P

    1996-01-01

    Optical spectroscopy and reverse-phase HPLC were used to investigate the binding of Hg(II) to plant metal-binding peptides (phytochelatins) with the structure (gammaGlu-Cys)2Gly, (gammaGlu-Cys)3Gly and (gammaGlu-Cys)4Gly. Glutathione-mediated transfer of Hg(II) into phytochelatins and the transfer of the metal ion from one phytochelatin to another was also studied using reverse-phase HPLC. The saturation of Hg(II)-induced bands in the UV/visible and CD spectra of (gammaGlu-Cys)2Gly suggested the formation of a single Hg(II)-binding species of this peptide with a stoichiometry of one metal ion per peptide molecule. The separation of apo-(gammaGlu-Cys)2Gly from its Hg(II) derivative on a C18 reverse-phase column also indicated the same metal-binding stoichiometry. The UV/visible spectra of both (gammaGlu-Cys)3Gly and (gammaGlu-Cys)4Gly at pH 7.4 showed distinct shoulders in the ligand-to-metal charge-transfer region at 280-290 mm. Two distinct Hg(II)-binding species, occurring at metal-binding stoichiometries of around 1.25 and 2.0 Hg(II) ions per peptide molecule, were observed for (gammaGlu-Cys)3Gly. These species exhibited specific spectral features in the charge-transfer region and were separable by HPLC. Similarly, two main Hg(II)-binding species of (gammaGlu-Cys)4Gly were observed by UV/visible and CD spectroscopy at metal-binding stoichiometries of around 1.25 and 2.5 respectively. Only a single peak of Hg(II)-(gammaGlu-Cys)4Gly complexes was resolved under the conditions used for HPLC. The overall Hg(II)-binding stoichiometries of phytochelatins were similar at pH 2.0 and at pH 7.4, indicating that pH did not influence the final Hg(II)-binding capacity of these peptides. The reverse-phase HPLC assays indicated a rapid transfer of Hg(II) from glutathione to phytochelatins. These assays also demonstrated a facile transfer of the metal ion from shorter- to longer-chain phytochelatins. The strength of Hg(II) binding to glutathione and phytochelatins followed the

  7. [Effects of Hg on soil enzyme activity].

    PubMed

    Yang, Chun-Lu; Sun, Tie-Heng; He, Wen-Xiang; Chen, Su

    2007-03-01

    With simulation test, this paper studied the effects of Hg on the activities of urease, invertase and neutral phosphotase in four soils. The results showed that Hg inhibited soil urease and invertase activities markedly, but its inhibitory effect differed with test soils. There was a significant logarithmic correlation between the concentration of HgCl2 and the activities of these two enzymes (P < 0.05). In test soils, the ED50 of urease activity was 87.99, 5.47, 24.05 and 19.88 mg x kg(-1), and that of invertase activity was 76.68, 727.49, 236.52 and 316.59 mg x kg(-1), respectively. Urease was more sensitive than invertase to Hg contamination, while organic matter had a protective effect on soil enzymes. Soil neutral phosphatase was not sensitive to Hg contamination, except that it was significantly activated by Hg in the meadow brown soil applied with plenty of organic fertilizer.

  8. Hg0 absorption in potassium persulfate solution*

    PubMed Central

    Ye, Qun-feng; Wang, Cheng-yun; Wang, Da-hui; Sun, Guan; Xu, Xin-hua

    2006-01-01

    The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (KPS) catalyzed by Ag+ was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption (CVAA) and ion chromatograph (IC), respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate (SN), temperature, Hg0 concentration in the reactor inlet and tertiary butanol (TBA), free radical scavenger, on the removal efficiency of Hg0 were studied. The results showed that the removal efficiency of Hg0 increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg0 was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO3. High Hg0 concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed. PMID:16615172

  9. Stabilization of Nanoparticulate HgS by Thiols and Humic Substances During HgS Precipitation

    NASA Astrophysics Data System (ADS)

    Hsu-Kim, H.; Deonarine, A.

    2008-12-01

    In the aquatic environment mercury has a strong affinity for reduced sulfur-containing ligands such as inorganic sulfides and thiolate functional groups in natural organic matter (NOM). Complexation of aqueous Hg(II) is particularly important because coordination to inorganic sulfide and humic compounds governs Hg(II) speciation (and subsequent bioavailability and mobility) in contaminated water and sediment. The purpose of this study was to explore the potential for NOM-coated HgS nanoparticles in the aquatic environment. HgS precipitation experiments were conducted in the presence of natural organic acids that are prevalent in surface water and sediment porewater. Dynamic light scattering was used to the monitor the size of HgS particles precipitating over time. The results indicated that humic substances decreased growth rates of precipitating HgS particles and stabilized particles with aggregate diameters smaller than 0.2 μm for at least 8 hours. Thiol-containing low molecular weight acids such as cysteine and thioglycolate also decreased growth of HgS particles whereas the hydroxyl-containing acids (serine and glycolate) did not affect particle growth rates. As the humic and thiol concentration increased in solution, growth rates of HgS particles decreased. Growth rates of the aggregates increased in solutions with greater ionic strength. Nanoparticles of HgS would be possible in aquatic environments where HgS precipitation is possible. We conducted equilibrium speciation calculations to determine HgS(s) saturation indices under conditions typical for sediment porewater. The calculations indicated that the metacinnabar saturation index was 1 to 3 orders of magnitude above or below saturation, depending on Hg-(bi)sulfide and Hg-NOM binding constants, which vary by orders of magnitude. These insights suggest that HgS nanoparticles may exist in surface waters and porewater of contaminated sediments as a result of kinetically-hindered mineralization reactions. Hg

  10. Is smaller better? Comparison of 3-mm and 5-mm leaf size for stereotactic radiosurgery: A dosimetric study

    SciTech Connect

    Chern, Shyh-shi . E-mail: Richard.Chern@hci.utah.edu; Leavitt, Dennis D.; Jensen, Randy L.; Shrieve, Dennis C.

    2006-11-15

    Purpose: To perform a dosimetric comparison of a minimal 3-mm leaf width multileaf collimator (MLC) and a minimal 5-mm MLC in dynamic conformal arc stereotactic radiosurgery for treatment of intracranial lesions. Methods and Materials: The treatment plans of 23 patients previously treated for intracranial lesions in our institution were redone using the BrainSCAN, version 5.3, stereotactic radiosurgery treatment planning system (BrainLAB). For each case, two dynamic conformal arc plans were generated: one using a minimal 3-mm micro-MLC (BrainLAB, Novalis) and one using a minimal 5-mm MLC (Varian Millennium). All arc parameters were the same in each of the two plans, except for the collimator angle settings. The collimator angle settings were optimized for each arc in each plan. A peritumoral rind structure (1 cm) was created to evaluate normal tissue sparing immediately adjacent to the target volume. Conformity indexes (CIs) were calculated for each plan. The dependence of normal tissue sparing and target conformity on target volume (TV) was determined. Results: The TV was 0.14-36.32 cm{sup 3} (median, 5.90). The CI was 1.22-2.60 (median, 1.51) for the 3-mm micro-MLC and 1.23-2.69 (median, 1.60) for the 5-mm MLC. Despite this small difference, it was a statistically significant increase (p < 0.0001) for the 5-mm MLC compared with the 3-mm micro-MLC. Improved normal tissue sparing was demonstrated using the 3-mm micro-MLC compared with the 5-mm MLC by examining the peritumoral rind volumes (PRVs) receiving 50% (PRV{sub 5}), 80% (PRV{sub 8}), and 90% (PRV{sub 9}) of the prescription dose. The reduction in the PRV{sub 5}, PRV{sub 8}, and PRV{sub 9} for the 3-mm micro-MLC compared with the 5-mm MLC was 13.5%, 12.9%, and 11.5%, respectively. The CI decreased with a larger TV, as did the difference in the CIs between the 3-mm micro-MLC and 5-mm MLC. A reduction in the PRV increased with larger TVs. Conclusion: The 3-mm micro-MLC provided better target conformity and

  11. Long-term Hg pollution induced Hg tolerance in the terrestrial isopod Porcellio scaber (Isopoda, Crustacea).

    PubMed

    Lapanje, A; Drobne, D; Nolde, N; Valant, J; Muscet, B; Leser, V; Rupnik, M

    2008-06-01

    The aim of our work was to assess the pollution-induced community tolerance (PICT) of isopod gut microbiota and pollution-induced isopod population tolerance (PIPT). Animals collected from a chronically Hg polluted and an unpolluted location were exposed for 14 days to 10microg Hg/g dry food under laboratory conditions. The lysosomal membrane stability, hepatopancreas epithelium thickness, feeding activity and animal bacterial gut microbiota composition were determined. The results confirm the hypothesis that the response to short-term Hg exposure differs for animals from the Hg polluted and the unpolluted field locations. The animals and their gut microbiota from the Hg polluted location were less affected by Hg in a short-term feeding experiment than those from the unpolluted environment. We discuss the pollution-induced population tolerance of isopods and their gut microbiota as a measure of effects of long-term environmental pollution. The ecological consequences of such phenomena are also discussed.

  12. Hg(II) Coordination Studies in Penicillamine Enantiomers by 199mHg-TDPAC

    NASA Astrophysics Data System (ADS)

    Tröger, W.; ISOLDE Collaboration

    2001-11-01

    In order to study the binding of the toxic heavy metal ion Hg2+ to penicillamine, complexes with the D- and L-enantiomers of penicillamine were investigated by the nuclear quadrupole interaction of 199Hg monitored by time differential perturbed angular correlation spectroscopy. It was found that bound Hg(II) occurs in two-fold, three-fold and four-fold coordinations.

  13. Prediction of Stereochemistry using Q2MM

    PubMed Central

    2016-01-01

    screens on a range of transition metal-catalyzed reactions that are important from both an industrial and an academic perspective. In this Account, we provide an overview of the continued improvement of the prediction of stereochemistry using Q2MM-derived TSFFs using four examples from different stages of development: (i) Pd-catalyzed allylation, (ii) OsO4-catalyzed asymmetric dihydroxylation (AD) of alkenes, (iii) Rh-catalyzed hydrogenation of enamides, and (iv) Ru-catalyzed hydrogenation of ketones. In the current form, correlation coefficients of 0.8–0.9 between calculated and experimental ee values are typical for a wide range of substrate–ligand combinations, and suitable ligands can be predicted for a given substrate with ∼80% accuracy. Although the generation of a TSFF requires an initial effort and will therefore be most useful for widely used reactions that require frequent screening campaigns, the method allows for a rapid virtual screen of large ligand libraries to focus experimental efforts on the most promising substrate–ligand combinations. PMID:27064579

  14. Prediction of Stereochemistry using Q2MM.

    PubMed

    Hansen, Eric; Rosales, Anthony R; Tutkowski, Brandon; Norrby, Per-Ola; Wiest, Olaf

    2016-05-17

    transition metal-catalyzed reactions that are important from both an industrial and an academic perspective. In this Account, we provide an overview of the continued improvement of the prediction of stereochemistry using Q2MM-derived TSFFs using four examples from different stages of development: (i) Pd-catalyzed allylation, (ii) OsO4-catalyzed asymmetric dihydroxylation (AD) of alkenes, (iii) Rh-catalyzed hydrogenation of enamides, and (iv) Ru-catalyzed hydrogenation of ketones. In the current form, correlation coefficients of 0.8-0.9 between calculated and experimental ee values are typical for a wide range of substrate-ligand combinations, and suitable ligands can be predicted for a given substrate with ∼80% accuracy. Although the generation of a TSFF requires an initial effort and will therefore be most useful for widely used reactions that require frequent screening campaigns, the method allows for a rapid virtual screen of large ligand libraries to focus experimental efforts on the most promising substrate-ligand combinations.

  15. Microbial Oxidation of Hg(0) - Its Effect on Hg Stable Isotope Fractionation and Methylmercury Production

    SciTech Connect

    Yee, Nathan; Barkay, Tamar; Reinfelder, John

    2016-06-28

    Mercury (Hg) associated with mixed waste generated by nuclear weapons manufacturing has contaminated vast areas of the Oak Ridge Reservation (ORR). Neurotoxic methylmercury (MeHg) has been formed from the inorganic Hg wastes discharged into headwaters of East Fork Poplar Creek (EFPC). Thus, understanding the processes and mechanisms that lead to Hg methylation along the flow path of EFPC is critical to predicting the impacts of the contamination and the design of remedial action at the ORR. In part I of our project, we investigated Hg(0) oxidation and methylation by anaerobic bacteria. We discovered that the anaerobic bacterium Desulfovibrio desulfuricans ND132 can oxidize elemental mercury [Hg(0)]. When provided with dissolved elemental mercury, D. desulfuricans ND132 converts Hg(0) to Hg(II) and neurotoxic methylmercury [MeHg]. We also demonstrated that diverse species of subsurface bacteria oxidizes dissolved elemental mercury under anoxic conditions. The obligate anaerobic bacterium Geothrix fermentans H5, and the facultative anaerobic bacteria Shewanella oneidensis MR-1 and Cupriavidus metallidurans AE104 can oxidize Hg(0) to Hg(II) under anaerobic conditions. In part II of our project, we established anaerobic enrichment cultures and obtained new bacterial strains from the DOE Oak Ridge site. We isolated three new bacterial strains from subsurface sediments collected from Oak Ridge. These isolates are Bradyrhizobium sp. strain FRC01, Clostridium sp. strain FGH, and a novel Negativicutes strain RU4. Strain RU4 is a completely new genus and species of bacteria. We also demonstrated that syntrophic interactions between fermentative bacteria and sulfate-reducing bacteria in Oak Ridge saprolite mediate iron reduction via multiple mechanisms. Finally, we tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge site, where nitrate is a major contaminant. We showed that there is an inverse

  16. The new barium zinc mercurides Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} - Synthesis, crystal and electronic structure

    SciTech Connect

    Schwarz, Michael; Wendorff, Marco; Roehr, Caroline

    2012-12-15

    The title compounds Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba{sub 3}ZnHg{sub 10} (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 4{sup 4} Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl{sub 4}. The flat pyramids are connected via Hg-Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M-M distances (273-301 pm; CN 9-11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317-348 pm) to their Zn/Hg neighbours. In the structure of BaZn{sub 0.6}Hg{sub 3.4} (cubic, cI320, space group I4{sup Macron }3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba{sub 3}ZnHg{sub 10}, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4 Multiplication-Sign 4 Multiplication-Sign 4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6){sub 4} with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4){sub 2} dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb{sub 3}Hg{sub 20} applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic

  17. HgCdTe barrier infrared detectors

    NASA Astrophysics Data System (ADS)

    Kopytko, M.; Rogalski, A.

    2016-05-01

    In the last decade, new strategies to achieve high-operating temperature (HOT) detectors have been proposed, including barrier structures such as nBn devices, unipolar barrier photodiodes, and multistage (cascade) infrared detectors. The ability to tune the positions of the conduction and valence band edges independently in a broken-gap type-II superlattices is especially helpful in the design of unipolar barriers. This idea has been also implemented in HgCdTe ternary material system. However, the implementation of this detector structure in HgCdTe material system is not straightforward due to the existence of a valence band discontinuity (barrier) at the absorber-barrier interface. In this paper we present status of HgCdTe barrier detectors with emphasis on technological progress in fabrication of MOCVD-grown HgCdTe barrier detectors achieved recently at the Institute of Applied Physics, Military University of Technology. Their performance is comparable with state-of-the-art of HgCdTe photodiodes. From the perspective of device fabrication their important technological advantage results from less stringent surface passivation requirements and tolerance to threading dislocations.

  18. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  19. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  20. Growing rice aerobically markedly decreases mercury accumulation by reducing both Hg bioavailability and the production of MeHg.

    PubMed

    Wang, Xun; Ye, Zhihong; Li, Bing; Huang, Linan; Meng, Mei; Shi, Jianbo; Jiang, Guibin

    2014-01-01

    Rice consumption represents a major route of mercury (Hg) and methylmercury (MeHg) exposure for those living in certain areas of inland China. In this study we investigated the effects of water management on bioavailable Hg, MeHg, and sulfate-reducing bacteria (SRB, abundance and community composition) in rhizosphere soil, and total Hg (THg) and MeHg in rice plants grown under glasshouse and paddy field conditions. Aerobic conditions greatly decreased the amount of THg and MeHg taken up by rice plants and affected their distribution in different plant tissues. There were positive correlations between bioavailable Hg and THg in brown rice and roots and between numbers of SRB and MeHg in brown rice, roots, and rhizosphere soil. Furthermore, the community composition of SRB was dramatically influenced by the water management regimes. Our results demonstrate that the greatly reduced bioavailability of Hg and production of MeHg are due to decreased SRB numbers and proportion of Hg methylators in the rhizosphere under aerobic conditions. These are the main reasons for the reduced Hg and MeHg accumulation in aerobically grown rice. Water management is indicated as an effective measure that can be used to reduce Hg and MeHg uptake by rice plants from Hg-contaminated paddy fields.

  1. Quasiparticle excitations in superdeformed [sup 192]Hg

    SciTech Connect

    Fallon, P. ); Lauritsen, T.; Ahmad, I.; Carpenter, M.P. ); Cederwall, B.; Clark, R.M. ); Crowell, B. ); Deleplanque, M.A.; Diamond, R.M. ); Gall, B.; Hannachi, F. ); Henry, R.G.; Janssens, R.V.F.; Khoo, T.L. ); Korichi, A. ); Lee, I.Y.; Macchiavelli, A.O. (Nuclear Science Division, Lawrence

    1995-04-01

    For the first time, two excited superdeformed (SD) bands have been observed in the double closed shell superdeformed nucleus [sup 192]Hg. One of the SD bands exhibits a pronounced peak in the dynamic moment of inertia which is interpreted as a crossing between two excited SD configurations involving the [ital N]=7 intruder and the [512]5/2 orbitals. This is only the second occurrence of such a crossing in a SD nucleus around [ital A]=190. The second excited SD band has near identical transition energies to an excited SD band in [sup 191]Hg.

  2. Adsorption of Hg on lunar samples

    SciTech Connect

    Reed, G.W. Jr.; Jovanovic, S.

    1985-01-01

    Understanding the presence, migration mechanisms and trapping of indigneous gases and volatiles on the moon is the objective of this study. The rare gases Ar and Xe and highly volatile Hg/sup 0/ and Br/sup 0/ (and/or their compounds) have been determined to be present in the lunar regolith. Evidence for these elements in the moon was recently reviewed. Studies of the sorption behavior of Xe on lunar material have been carried out. We report here preliminary results of a study designed to rationalize the behavior of Hg in lunar material.

  3. 40 CFR 60.45Da - Standard for mercury (Hg).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for mercury (Hg). 60.45Da... for mercury (Hg). (a) For each coal-fired electric utility steam generating unit other than an IGCC... gases that contain mercury (Hg) emissions in excess of each Hg emissions limit in paragraphs...

  4. 40 CFR 60.45Da - Standard for mercury (Hg).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standard for mercury (Hg). 60.45Da... for mercury (Hg). (a) For each coal-fired electric utility steam generating unit other than an IGCC... gases that contain mercury (Hg) emissions in excess of each Hg emissions limit in paragraphs...

  5. Tracing historical trends of Hg in the Mississippi River using Hg concentrations and Hg isotopic compositions in a lake sediment core, Lake Whittington, Mississippi, USA

    USGS Publications Warehouse

    Gray, John E.; Van Metre, Peter C.; Pribil, Michael J.; Horowitz, Arthur J.

    2015-01-01

    Concentrations and isotopic compositions of mercury (Hg) in a sediment core collected from Lake Whittington, an oxbow lake on the Lower Mississippi River, were used to evaluate historical sources of Hg in the Mississippi River basin. Sediment Hg concentrations in the Lake Whittington core have a large 10-15 y peak centered on the 1960s, with a maximum enrichment factor relative to Hg in the core of 4.8 in 1966. The Hg concentration profile indicates a different Hg source history than seen in most historical reconstructions of Hg loading. The timing of the peak is consistent with large releases of Hg from Oak Ridge National Laboratory (ORNL), primarily in the late 1950s and 1960s. Mercury was used in a lithiumisotope separation process by ORNL and an estimated 128Mg (megagrams) of Hgwas discharged to a local stream that flows into the Tennessee River and, eventually, the Mississippi River. Mass balance analyses of Hg concentrations and isotopic compositions in the Lake Whittington core fit a binary mixing model with a Hg-rich upstream source contributing about 70% of the Hg to Lake Whittington at the height of the Hg peak in 1966. This upstream Hg source is isotopically similar to Hg isotope compositions of stream sediment collected downstream near ORNL. It is estimated that about one-half of the Hg released from the ORNL potentially reached the LowerMississippi River basin in the 1960s, suggesting considerable downstream transport of Hg. It is also possible that upstream urban and industrial sources contributed some proportion of Hg to Lake Whittington in the 1960s and 1970s.

  6. Mercuric chloride (HgCl2)

    Integrated Risk Information System (IRIS)

    Mercuric chloride ( HgCl2 ) ; CASRN 7487 - 94 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonc

  7. Hg stable isotope analysis by the double-spike method.

    PubMed

    Mead, Chris; Johnson, Thomas M

    2010-06-01

    Recent publications suggest great potential for analysis of Hg stable isotope abundances to elucidate sources and/or chemical processes that control the environmental impact of mercury. We have developed a new MC-ICP-MS method for analysis of mercury isotope ratios using the double-spike approach, in which a solution containing enriched (196)Hg and (204)Hg is mixed with samples and provides a means to correct for instrumental mass bias and most isotopic fractionation that may occur during sample preparation and introduction into the instrument. Large amounts of isotopic fractionation induced by sample preparation and introduction into the instrument (e.g., by batch reactors) are corrected for. This may greatly enhance various Hg pre-concentration methods by correcting for minor fractionation that may occur during preparation and removing the need to demonstrate 100% recovery. Current precision, when ratios are normalized to the daily average, is 0.06 per thousand, 0.06 per thousand, 0.05 per thousand, and 0.05 per thousand (2sigma) for (202)Hg/(198)Hg, (201)Hg/(198)Hg, (200)Hg/(198)Hg, and (199)Hg/(198)Hg, respectively. This is slightly better than previously published methods. Additionally, this precision was attained despite the presence of large amounts of other Hg isotopes (e.g., 5.0% atom percent (198)Hg) in the spike solution; substantially better precision could be achieved if purer (196)Hg were used.

  8. Application of MM wave therapy in radiology

    SciTech Connect

    Avakian, R.S.; Gasparyan, L.V.

    1995-12-31

    The authors studied the effects of MM wave electromagnetic radiation influence on patients, affected by X-ray radiation during the reparation works after Chernobyl nuclear power plant exposure. They compared results of treatment of two groups of patients: (1) control group patients received only basis therapy; (2) testing group, 10 patients received basis therapy and MM wave influence. The authors used the wide band noise generator `Artsakh - 2` for local irradiation on the acupuncture points. Their data proved that low intensity MM waves have immunocorrective, antioxidant effects, and MM wave therapy is a perspective method for treatment of patients with radiological pathology.

  9. Evolution of collectivity in {sup 180}Hg and {sup 182}Hg

    SciTech Connect

    Grahn, T.; Petts, A.; Scheck, M.; Butler, P. A.; Page, R. D.; Dewald, A.; Jolie, J.; Melon, B.; Pissulla, Th.; Hornillos, M. B. Gomez; Greenlees, P. T.; Jones, P.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Nyman, M.; Rahkila, P.; Saren, J.; Scholey, C.

    2009-07-15

    Lifetimes of yrast states in {sup 180}Hg up to the 8{sup +} state and of the 9{sup -} state have been extracted from recoil-decay tagged {gamma}-ray spectra by using the recoil distance Doppler-shift method. In addition, lifetimes of yrast states up to the 10{sup +} state in {sup 182}Hg have been extracted from recoil-gated {gamma}{gamma}-coincidence spectra. The present study addresses the evolution of collectivity of two competing shapes in neutron-deficient Hg nuclei as a function of A and the configuration mixing at low spin.

  10. Investigation of uptake and retention of atmospheric Hg(II) by boreal forest plants using stable Hg isotopes

    USGS Publications Warehouse

    Graydon, J.A.; St. Louis, V.L.; Hintelmann, H.; Lindberg, S.E.; Sandilands, K.A.; Rudd, J.W.M.; Kelly, C.A.; Tate, M.T.; Krabbenhoft, D.P.; Lehnherr, I.

    2009-01-01

    Although there is now a general consensus among mercury (Hg) biogeochemists that increased atmospheric inputs of inorganic Hg(II) to lakes and watersheds can result in increased methylmercury (MeHg) concentrations in fish, researchers still lack kinetic data describing the movement of Hg from the atmosphere, through watershed and lake ecosystems, and into fish. The use of isotopically enriched Hg species in environmental studies now allows experimentally applied new Hg to be distinguished from ambient Hg naturally present in the system. Four different enriched stable Hg(II) isotope "spikes" were applied sequentially over four years to the ground vegetation of a microcatchment at the Experimental Lakes Area (ELA) in the remote boreal forest of Canada to examine retention of Hg(II) following deposition. Areal masses of the spikes and ambient THg (all forms of Hg in a sample) were monitored for eight years, and the pattern of spike retention was used to estimate retention of newly deposited ambient Hg within the ground vegetation pool. Fifty to eighty percent of applied spike Hg was initially retained by ground vegetation. The areal mass of spike Hg declined exponentially over time and was best described by a first-order process with constants (k) ranging between 9.7 ?? 10-4 day -1 and 11.6 ?? 10-4 day-1. Average half-life (t1/2) of spike Hg within the ground vegetation pool (??S.D.) was 704 ?? 52 days. This retention of new atmospheric Hg(II) by vegetation delays movement of new Hg(II) into soil, runoff, and finally into adjacent lakes. Ground-applied Hg(II) spikes were not detected in tree foliage and litterfall, indicating that stomatal and/or root uptake of previously deposited Hg (i.e., "recycled" from ground vegetation or soil Hg pools) were likely not large sources of foliar Hg under these experimental conditions. ?? 2009 American Chemical Society.

  11. Investigation of uptake and retention of atmospheric Hg(II) by boreal forest plants using stable Hg isotopes.

    PubMed

    Graydon, Jennifer A; St Louis, Vincent L; Hintelmann, Holger; Lindberg, Steve E; Sandilands, Ken A; Rudd, John W M; Kelly, Carol A; Tate, Michael T; Krabbenhoft, Dave P; Lehnherr, Igor

    2009-07-01

    Although there is now a general consensus among mercury (Hg) biogeochemists that increased atmospheric inputs of inorganic Hg(II) to lakes and watersheds can result in increased methylmercury (MeHg) concentrations in fish, researchers still lack kinetic data describing the movement of Hg from the atmosphere, through watershed and lake ecosystems, and into fish. The use of isotopically enriched Hg species in environmental studies now allows experimentally applied new Hg to be distinguished from ambient Hg naturally present in the system. Four different enriched stable Hg(II) isotope "spikes" were applied sequentially over four years to the ground vegetation of a microcatchment at the Experimental Lakes Area (ELA) in the remote boreal forest of Canada to examine retention of Hg(II) following deposition. Areal masses of the spikes and ambient THg (all forms of Hg in a sample) were monitored for eight years, and the pattern of spike retention was used to estimate retention of newly deposited ambient Hg within the ground vegetation pool. Fifty to eighty percent of applied spike Hg was initially retained by ground vegetation. The areal mass of spike Hg declined exponentially over time and was best described by a first-order process with constants(k) ranging between 9.7 x 10(-40 day(-1) and 11.6 x 10(-4) day(-1). Average halflife (t1/2) of spike Hg within the ground vegetation pool (+/-S.D.) was 704 +/- 52 days. This retention of new atmospheric Hg(II) by vegetation delays movement of new Hg(II) into soil, runoff, and finally into adjacent lakes. Ground-applied Hg(II) spikes were not detected in tree foliage and litterfall, indicating that stomatal and/or root uptake of previously deposited Hg (i.e., "recycled" from ground vegetation or soil Hg pools) were likely not large sources of foliar Hg under these experimental conditions.

  12. Isotopic abundances of Hg in mercury stars inferred from the Hg II line at 3984 A

    NASA Technical Reports Server (NTRS)

    White, R. E.; Vaughan, A. H., Jr.; Preston, G. W.; Swings, J. P.

    1976-01-01

    Wavelengths of the Hg II absorption feature at 3984 A in 30 Hg stars are distributed uniformly from the value for the terrestrial mix to a value that corresponds to nearly pure Hg-204. The wavelengths are correlated loosely with effective temperatures inferred from Q(UBV). Relative isotopic abundances derived from partially resolved profiles of the 3984-A line in iota CrB, chi Lup, and HR 4072 suggest that mass-dependent fractionation has occurred in all three stars. It is supposed that such fractionation occurs in all Hg stars, and a scheme whereby isotopic compositions can be inferred from a comparison of stellar wavelengths and equivalent widths with those calculated for a family of fractionated isotopic mixes. Theoretical profiles calculated for the derived isotopic composition agree well with high-resolution interferometric profiles obtained for three of the stars.

  13. Compton profiles and electronic structure of HgBr(2) and HgI(2).

    PubMed

    Ahmed, G; Dashora, Alpa; Sharma, M; Ahuja, B L

    2010-02-01

    In this paper, we present the first-ever experimental Compton line shapes of HgBr(2) and HgI(2) using (137)Cs Compton spectrometer. To compare our experimental momentum densities, we have computed the Compton profiles using Hartree-Fock and density functional theory within linear combination of atomic orbitals. We have also computed the energy bands and density of states using the linear combination of atomic orbitals and full potential linearized augmented plane wave method. On the basis of equal-valence-electron-density profiles, it is seen that HgI(2) is more covalent than HgBr(2) which is in agreement with the valence charge densities. The experimental isotropic profiles are found to be relatively in better agreement with the Hartree-Fock data. We have also discussed the photoluminescence and detection properties of both the halides.

  14. MM Algorithms for Some Discrete Multivariate Distributions.

    PubMed

    Zhou, Hua; Lange, Kenneth

    2010-09-01

    The MM (minorization-maximization) principle is a versatile tool for constructing optimization algorithms. Every EM algorithm is an MM algorithm but not vice versa. This article derives MM algorithms for maximum likelihood estimation with discrete multivariate distributions such as the Dirichlet-multinomial and Connor-Mosimann distributions, the Neerchal-Morel distribution, the negative-multinomial distribution, certain distributions on partitions, and zero-truncated and zero-inflated distributions. These MM algorithms increase the likelihood at each iteration and reliably converge to the maximum from well-chosen initial values. Because they involve no matrix inversion, the algorithms are especially pertinent to high-dimensional problems. To illustrate the performance of the MM algorithms, we compare them to Newton's method on data used to classify handwritten digits.

  15. X-ray Structure of a Hg2+ Complex of Mercuric Reductase (MerA) and Quantum Mechanical/Molecular Mechanical Study of Hg2+ Transfer between the C-Terminal and Buried Catalytic Site Cysteine Pairs

    PubMed Central

    2015-01-01

    Mercuric reductase, MerA, is a key enzyme in bacterial mercury resistance. This homodimeric enzyme captures and reduces toxic Hg2+ to Hg0, which is relatively unreactive and can exit the cell passively. Prior to reduction, the Hg2+ is transferred from a pair of cysteines (C558′ and C559′ using Tn501 numbering) at the C-terminus of one monomer to another pair of cysteines (C136 and C141) in the catalytic site of the other monomer. Here, we present the X-ray structure of the C-terminal Hg2+ complex of the C136A/C141A double mutant of the Tn501 MerA catalytic core and explore the molecular mechanism of this Hg transfer with quantum mechanical/molecular mechanical (QM/MM) calculations. The transfer is found to be nearly thermoneutral and to pass through a stable tricoordinated intermediate that is marginally less stable than the two end states. For the overall process, Hg2+ is always paired with at least two thiolates and thus is present at both the C-terminal and catalytic binding sites as a neutral complex. Prior to Hg2+ transfer, C141 is negatively charged. As Hg2+ is transferred into the catalytic site, a proton is transferred from C136 to C559′ while C558′ becomes negatively charged, resulting in the net transfer of a negative charge over a distance of ∼7.5 Å. Thus, the transport of this soft divalent cation is made energetically feasible by pairing a competition between multiple Cys thiols and/or thiolates for Hg2+ with a competition between the Hg2+ and protons for the thiolates. PMID:25343681

  16. Identification of Atmospheric Mercury Input to Ecosystems From Precipitation Using Coupled Δ200Hg and Δ204Hg Fractionation

    NASA Astrophysics Data System (ADS)

    Blum, J. D.; Johnson, M. W.

    2015-12-01

    Mercury has seven stable isotopes, and during most biogeochemical reactions all of the isotopes fractionate mass dependently (MDF; relative to δ202/198Hg). The odd isotopes also fractionate mass independently (MIF) during reactions involving the magnetic isotope and nuclear volume effects. In 2010 we first reported MIF of 200Hg in precipitation (Gratz et al), and in 2013 we reported MIF of 204Hg in precipitation (Demers et al). Measurements of Δ200Hg are becoming more common and several studies have now used Δ200Hg as a tracer of Hg(II) deposited from the atmosphere (Chen et al, 2012; Strok et al 2015). Δ204Hg is much less commonly measured and reported, but sheds additional light on the mechanisms that might cause even isotope MIF. We observe Δ204Hg to be of opposite sign and ~2x the magnitude of Δ200Hg. The presence of coupled Δ200Hg and Δ204Hg is most useful for detecting precipitation inputs of Hg to ecosystems. We have measured Δ200Hg and Δ204Hg in hundreds of samples of precipitation, invertebrates, fish, moss, lichen, ice crystals and GEM at many locations in North America and Hawaii. When average values for each sample type at each study location are plotted as Δ200Hg versus Δ204Hg they fall on a linear array with slope=0.57 and R2=0.92. Samples of sediment, coal, various rock-types, and point-source contaminants have contrasting Δ200Hg and Δ204Hg indistinguishable from zero. We also use combined Δ200Hg and Δ204Hg to explore mechanisms leading to even isotope MIF. Ghosh et al (2012) measured nuclear volume fractionation and found even MIF to be undetectable. Mead et al (2013) calculated even mass MIF from nuclear self-shielding and it does not fit our observations of Δ200Hg/Δ204Hg in natural samples; they also measured MIF caused by implantation of Hg into glass in compact fluorescent lights (CFLs) and this is consistent with Δ200Hg/Δ204Hg in atmospheric Hg(II), suggesting the possibility of a common fractionation mechanism.

  17. Analysis of RFSA Campaign No.2 Dissolver Solution for Hg(I) and Hg(II)

    SciTech Connect

    Holcomb, H.P.

    2001-05-17

    TA 2-1083, under which RFSA processing is conducted, calls for a nominal mercuric ion concentration in the dissolver solution of 0.006M with a maximum of 0.01 M. The second RFSA campaign operated according to these guidelines with the initial Hg(II) concentration being 0.0068 M. Part of this study is to ascertain optimum excess Hg(I) for chloride removal.

  18. Crystal growth and characterization of Hg-based chalcogenide compounds (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    He, Yihui; Lin, Wenwen; Syrigos, Jonathan C.; Wang, Peng Li; Islam, Saiful M.; McCall, Kyle M.; Kostina, Svetlana S.; Liu, Zhifu; Wessels, Bruce W.; Kanatzidis, Mercouri G.

    2016-09-01

    In this work, two Hg-based chalcogenides were investigated in detail to reveal their potential capability of radiation detection at room temperature (RT). Cs2Hg6S7, with a bandgap of 1.63 eV, which is designed by the dimensional reduction theory proposed by our group, were prepared and characterized. α-HgS, with a bandgap of 2.10 eV, as a precursor used for the ternary compound synthesis, was also proposed and further investigated. For Cs2Hg6S7, the crystals tended to crystallize into needle form with small grains. Here, the conditions of Bridgman melt growth were optimized to obtain relatively large single crystals. The slight excess of Cs2S as a fluxing agent during growth was found to facilitate better crystallization and large grains. Interestingly, no inclusion or secondary phase was found in the as-grown single crystals. The improvement of bulk resistivity from 10^6 Ωcm to 10^8 Ωcm was also achieved through the control of stoichiometry during crystal growth. For α-HgS crystals, both physical vapor transport and chemical vapor transport methods have been applied. By modifying the transport temperature and transport agent, single crystal with size about 3x1.5 mm^2 was grown with resistivity higher than 10^11 Ωcm. Photoluminescence (PL) revealed that multiple peaks observed in the 1.6-2.3 eV range and excitonic peak from for α-HgS single crystals were observed indicating good crystalline quality. Finally, the planar detectors for both crystals were tested under Co57 gamma ray source. Both of the crystals showed reasonable gamma ray response, while α-HgS crystals could respond at a relatively higher counting rate.

  19. Characterization of Electronic Materials HgZnSe and HgZnTe Using Innovative and Conventional Techniques

    NASA Technical Reports Server (NTRS)

    Tanton, George; Kesmodel, Roy; Burden, Judy; Su, Ching-Hua; Cobb, Sharon D.; Lehoczky, S. L.

    2000-01-01

    HgZnSe and HgZnTe are electronic materials of interest for potential IR detector and focal plane array applications due to their improved strength and compositional stability over HgCdTe, but they are difficult to grow on Earth and to fully characterize. Conventional contact methods of characterization, such as Hall and van der Paw, although adequate for many situations are typically labor intensive and not entirely suitable where only very small samples are available. To adequately characterize and compare properties of electronic materials grown in low earth orbit with those grown on Earth, innovative techniques are needed that complement existing methods. This paper describes the implementation and test results of a unique non-contact method of characterizing uniformity, mobility, and carrier concentration together with results from conventional methods applied to HgZnSe and HgZnTe. The innovative method has advantages over conventional contact methods since it circumvents problems of possible contamination from alloying electrical contacts to a sample and also has the capability to map a sample. Non- destructive mapping, the determination of the carrier concentration and mobility at each place on a sample, provides a means to quantitatively compare, at high spatial resolution, effects of microgravity on electronic properties and uniformity of electronic materials grown in low-Earth orbit with Earth grown materials. The mapping technique described here uses a 1mm diameter polarized beam of radiation to probe the sample. Activation of a magnetic field, in which the sample is placed, causes the plane of polarization of the probe beam to rotate. This Faraday rotation is a function of the free carrier concentration and the band parameters of the material. Maps of carrier concentration, mobility, and transmission generated from measurements of the Faraday rotation angles over the temperature range from 300K to 77K will be presented. New information on band parameters

  20. Magnetic fields of HgMn stars⋆

    NASA Astrophysics Data System (ADS)

    Hubrig, S.; González, J. F.; Ilyin, I.; Korhonen, H.; Schöller, M.; Savanov, I.; Arlt, R.; Castelli, F.; Lo Curto, G.; Briquet, M.; Dall, T. H.

    2012-11-01

    Context. The frequent presence of weak magnetic fields on the surface of spotted late-B stars with HgMn peculiarity in binary systems has been controversial during the two last decades. Recent studies of magnetic fields in these stars using the least-squares deconvolution (LSD) technique have failed to detect magnetic fields, indicating an upper limit on the longitudinal field between 8 and 15 G. In these LSD studies, assumptions were made that all spectral lines are identical in shape and can be described by a scaled mean profile. Aims: We re-analyse the available spectropolarimetric material by applying the moment technique on spectral lines of inhomogeneously distributed elements separately. Furthermore, we present new determinations of the mean longitudinal magnetic field for the HgMn star HD 65949 and the hotter analog of HgMn stars, the PGa star HD 19400, using FORS 2 installed at the VLT. We also give new measurements of the eclipsing system AR Aur with a primary star of HgMn peculiarity, which were obtained with the SOFIN spectropolarimeter installed at the Nordic Optical Telescope. Methods: We downloaded from the European Southern Observatory (ESO) archive the publically available HARPS spectra for eight HgMn stars and one normal and one superficially normal B-type star obtained in 2010. Out of this sample, three HgMn stars belong to spectroscopic double-lined systems. The application of the moment technique to the HARPS and SOFIN spectra allowed us to study the presence of the longitudinal magnetic field, the crossover effect, and quadratic magnetic fields. Results for the HgMn star HD 65949 and the PGa star HD 19400 are based on a linear regression analysis of low-resolution spectra obtained with FORS 2 in spectropolarimetric mode. Results: Our measurements of the magnetic field with the moment technique using spectral lines of several elements separately reveal the presence of a weak longitudinal magnetic field, a quadratic magnetic field, and the

  1. Mercury (Hg) and methyl mercury (MeHg) concentrations in fish from the coastal lagoon of Orbetello, central Italy.

    PubMed

    Miniero, R; Beccaloni, E; Carere, M; Ubaldi, A; Mancini, L; Marchegiani, S; Cicero, M R; Scenati, R; Lucchetti, D; Ziemacki, G; De Felip, E

    2013-11-15

    Total mercury (Hg tot) and methyl mercury (MeHg) were quantified in several specimens of Dicentrarchus labrax and Sparus aurata from the east basin of the Orbetello lagoon, central Italy. The size of each specimen was recorded to estimate body burdens (BBs); =Hg tot and MeHg were measured in fillets of both species. Hg tot and MeHg in S. aurata ranged between 0.355-1.58 and 0.341-1.53 μg/g wet weight (ww), respectively; in D. labrax, their ranges were 0.284-2.54 and 0.214-2.35 μg/g ww. Approximately 90% of the concentrations measured exceeded Hg tot regulatory maximum level of 0.5 μg/g ww; however, exceedance rate was different in the two species studied. No correlations between specimen size and Hg tot or MeHg BBs were detected in this study.

  2. A theoretical study of the oxidation of Hg0 to HgBr2 in the troposphere.

    PubMed

    Goodsite, M E; Plane, J M C; Skov, H

    2004-03-15

    The oxidation of elemental mercury (Hg0) to the divalent gaseous mercury dibromide (HgBr2) has been proposed to account for the removal of Hg0 during depletion events in the springtime Arctic. The mechanism of this process is explored in this paper by theoretical calculations of the relevant rate coefficients. Rice-Ramsberger-Kassel-Marcus (RRKM) theory, together with ab initio quantum calculations where required, are used to estimate the following: recombination rate coefficients of Hg with Br, I, and O; the thermal dissociation rate coefficient of HgBr; and the recombination rate coefficients of HgBr with Br, I, OH, and O2. A mechanism based on the initial recombination of Hg with Br, followed by the addition of a second radical (Br, I, or OH) in competition with thermal dissociation of HgBr, is able to account for the observed rate of Hg0 removal, both in Arctic depletion events and at lower latitudes.

  3. Estimate interaction timing in a large volume HgI2 detector using cathode pulse waveforms

    PubMed Central

    Meng, L.J.; He, Z.

    2016-01-01

    This paper presents experimental results on the timing resolution achieved with a 5 mm thick HgI2 detector. The timing information was derived based on the cathode pre-amplifier pulse waveform, measured using a digital oscilloscope. The times of interaction were estimated by fitting the measured pulse waveforms to pre-defined waveform models. With this approach, problems related to the conventional leading edge or constant fraction triggering, such as slow charge carrier mobility, pulse shape variation and depth-dependent detector response can be greatly reduced. As a result, we showed a 13 ns timing resolution measured using the 5 mm thick HgI2 detector and a BaF2 coincidence detector with 511 keV full energy events. In this paper, we discuss several waveform models and the results achieved using these models. PMID:28260824

  4. Multimedia contents production system (MM-CPS)

    NASA Astrophysics Data System (ADS)

    Roser, Miguel; Villegas, Paulo; Simon, Maria; Hernandez-Gil, J. F.; Aguado, Isidro

    1996-01-01

    A present characterized by deep worldwide changes, and a future where social relations and behaviors are going to undergo a substantial change need new telecommunications services in order to allow people to get closer, facilitate their daily tasks and place at their disposal multimedia information to be accessed anywhere and at any time. These new services are very dependent on the contents to be included in the applications. The purpose of this paper is to describe an universal MM contents production system (MM-CPS), which allows the generation of coded data files suitable to be included in MM-servers.

  5. A physiological role for HgII during phototrophic growth

    NASA Astrophysics Data System (ADS)

    Grégoire, D. S.; Poulain, A. J.

    2016-02-01

    The bioaccumulation of toxic monomethylmercury is influenced by the redox reactions that determine the amount of mercury (Hg) substrate--HgII or Hg0 (refs ,)--that is available for methylation. Phototrophic microorganisms can reduce HgII to Hg0 (ref. ). This reduction has been linked to a mixotrophic lifestyle, in which microbes gain energy photosynthetically but acquire diverse carbon compounds for biosynthesis from the environment. Photomixotrophs must maintain redox homeostasis to disperse excess reducing power due to the accumulation of reduced enzyme cofactors. Here we report laboratory experiments in which we exposed purple bacteria growing in a bioreactor to HgII and monitored Hg0 concentrations. We show that phototrophs use HgII as an electron sink to maintain redox homeostasis. Hg0 concentrations increased only when bacteria grew phototrophically, and when bacterial enzyme cofactor ratios indicated the presence of an intracellular redox imbalance. Under such conditions, bacterial growth rates increased with increasing HgII concentrations; when alternative electron sinks were added, Hg0 production decreased. We conclude that Hg can fulfil a physiological function in bacteria, and that photomixotrophs can modify the availability of Hg to methylation sites.

  6. 40 CFR 80.107-80.124 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false 80.107-80.124 Section 80.107-80.124 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Anti-Dumping §§ 80.107-80.124...

  7. 40 CFR 80.1200-80.1219 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false 80.1200-80.1219 Section 80.1200-80.1219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene §§ 80.1200-80.1219 General Information...

  8. 40 CFR 80.1200-80.1219 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false 80.1200-80.1219 Section 80.1200-80.1219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene §§ 80.1200-80.1219 General Information...

  9. 40 CFR 80.1200-80.1219 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false 80.1200-80.1219 Section 80.1200-80.1219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene §§ 80.1200-80.1219 General Information...

  10. 40 CFR 80.134-80.135 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.134-80.135 Section 80.134-80.135 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Attest Engagements §§ 80.134-80.135...

  11. 40 CFR 80.142-80.154 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false 80.142-80.154 Section 80.142-80.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Detergent Gasoline §§ 80.142-80.154...

  12. 40 CFR 80.142-80.154 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false 80.142-80.154 Section 80.142-80.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Detergent Gasoline §§ 80.142-80.154...

  13. 40 CFR 80.142-80.154 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.142-80.154 Section 80.142-80.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Detergent Gasoline §§ 80.142-80.154...

  14. 40 CFR 80.142-80.154 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false 80.142-80.154 Section 80.142-80.154 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Detergent Gasoline §§ 80.142-80.154...

  15. MM Algorithms for Geometric and Signomial Programming.

    PubMed

    Lange, Kenneth; Zhou, Hua

    2014-02-01

    This paper derives new algorithms for signomial programming, a generalization of geometric programming. The algorithms are based on a generic principle for optimization called the MM algorithm. In this setting, one can apply the geometric-arithmetic mean inequality and a supporting hyperplane inequality to create a surrogate function with parameters separated. Thus, unconstrained signomial programming reduces to a sequence of one-dimensional minimization problems. Simple examples demonstrate that the MM algorithm derived can converge to a boundary point or to one point of a continuum of minimum points. Conditions under which the minimum point is unique or occurs in the interior of parameter space are proved for geometric programming. Convergence to an interior point occurs at a linear rate. Finally, the MM framework easily accommodates equality and inequality constraints of signomial type. For the most important special case, constrained quadratic programming, the MM algorithm involves very simple updates.

  16. QM/MM methods in inorganic chemistry.

    PubMed

    Bo, Carles; Maseras, Feliu

    2008-06-14

    Quantum mechanics/molecular mechanics (QM/MM) methods are a useful tool for the computational study of inorganic systems. They allow a quantitative description of systems larger than those treatable with pure QM methods, in principle with a comparable quality. QM/MM calculations are being currently applied to the research in a variety of topics, including structural effects of ligand bulk, selectivity in homogeneous catalysis and mechanical embedding in heterogeneous catalysis. The QM/MM approach is also useful for the separation of steric and electronic contributions, and as an auxiliary tool for geometry optimization when full QM methods are mandatory. The power of QM/MM methods in inorganic chemistry is illustrated in this Perspective with a summary of recent representative applications.

  17. Mercury (Hg) and oxidative stress status in healthy mothers and its effect on birth anthropometric measures.

    PubMed

    Al-Saleh, Iman; Al-Rouqi, Reem; Obsum, Cercilia Angela; Shinwari, Neptune; Mashhour, Abdullah; Billedo, Grisellhi; Al-Sarraj, Yaser; Rabbah, Abdullah

    2014-01-01

    This study was conducted to: (a) investigate the antagonistic interaction between selenium (Se) and mercury (Hg) in mothers and their newborns, (b) delineate the role of oxidative mechanisms induced by Hg exposure and (c) examine the protective effect of Se on Hg-induced oxidative stress and birth outcomes. Levels of Hg and Se were measured in umbilical cord blood and the placentas of 250 healthy mothers who participated in a study between 2006 and 2006 assessing prenatal exposure various pollutants. Levels of malondialdehyde (MDA) in cord and maternal blood and of 8-hydroxy-2-deoxyguanosine in urine were measured for assessing oxidative stress. Tail moment (TM) in the comet assay, as a biomarker of DNA damage was measured in samples of cord and maternal blood. The mean Se levels in umbilical cord blood (67.618±12.897μg/l) were lower than those reported in many countries, but none of the newborns had Se levels <20μg/l (the threshold limit of Keshan disease). More than 80% of the newborns, though, had Se levels below the 80μg/l needed for maximum glutathione peroxidase activity. Even though 18.6% of the newborns had levels of Hg ≥5.8μg/l (the reference dose of the Environmental Protection Agency), no relationship was observed with the biomarkers of oxidative stress. The mean placental Hg levels (0.056±0.075μg/g dry wt.) were higher than those reported for newborns with abnormal fetal development. Our study also documented significant placental transfer of Hg and Se to the fetus. The Hg/Se molar ratio in both cord blood and placental tissue was well below 1. The average amount of Se in both matrices was approximately 50-fold in molar excess over Hg. The molar excess of Se in the umbilical cord (0.843μmol/l), however, was lower than in placental tissues (13.098μmol/kg dry wt.). In further support of the relationships of Hg and Se on oxidative stress, we observed significantly lower levels of maternal MDA associated with Se levels in both cord blood and

  18. Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007.

    PubMed

    Tian, Hezhong; Wang, Yan; Xue, Zhigang; Qu, Yiping; Chai, Fahe; Hao, Jiming

    2011-07-15

    Over half of coal in China is burned directly by power plants, becoming an important source of hazardous trace element emissions, such as mercury (Hg), arsenic (As), and selenium (Se), etc. Based on coal consumption by each power plant, emission factors classified by different boiler patterns and air pollution control devices configuration, atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are evaluated. The national total emissions of Hg, As, and Se from coal-fired power plants in 2007 are calculated at 132 t, 550 t, and 787 t, respectively. Furthermore, according to the percentage of coal consumed by units equipped with different types of PM devices and FGD systems, speciation of mercury is estimated as follows: 80.48 t of Hg, 49.98 t of Hg(2+), and 1.89 t of Hg(P), representing 60.81%, 37.76%, and 1.43% of the totals, respectively. The emissions of Hg, As, and Se in China's eastern and central provinces are much higher than those in the west, except for provinces involved in the program of electricity transmission from west to east China, such as Sichuan, Guizhou, Yunnan, Shaanxi, etc.

  19. Evaluation on the stability of Hg in ABS disk CRM during measurements by wavelength dispersive X-ray fluorescence spectrometry.

    PubMed

    Ohata, Masaki; Kidokoro, Toshihiro; Hioki, Akiharu

    2012-01-01

    The stability of Hg in an acrylonitrile-butadiene-styrene disk certified reference material (ABS disk CRM, NMIJ CRM 8116-a) during measurements by wavelength dispersion X-ray fluorescence (WD-XRF) analysis was evaluated in this study. The XRF intensities of Hg (L(α)) and Pb (L(α)) as well as the XRF intensity ratios of Hg (L(α))/Pb (L(α)) observed under different X-ray tube current conditions as well as their irradiation time were examined to evaluate the stability of Hg in the ABS disk CRM. The observed XRF intensities and the XRF intensity ratios for up to 32 h of measurements under 80 mA of X-ray tube current condition were constant, even though the surface of the ABS disk CRM was charred by the X-ray irradiation with high current for a long time. Moreover, the measurements on Hg and Pb in the charred disks by an energy dispersive XRF (ED-XRF) spectrometer showed constant XRF intensity ratios of Hg (L(α))/Pb (L(α)). From these results, Hg in the ABS disk CRM was evaluated to be sufficiently stable for XRF analysis.

  20. 40 CFR 60.4124 - Hg budget permit revisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Hg budget permit revisions. 60.4124... Coal-Fired Electric Steam Generating Units Permits § 60.4124 Hg budget permit revisions. Except as provided in § 60.4123(b), the permitting authority will revise the Hg Budget permit, as necessary,...

  1. 40 CFR 60.4124 - Hg budget permit revisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Hg budget permit revisions. 60.4124... Coal-Fired Electric Steam Generating Units Permits § 60.4124 Hg budget permit revisions. Except as provided in § 60.4123(b), the permitting authority will revise the Hg Budget permit, as necessary,...

  2. 29 mm Diameter Test Target Design Report

    SciTech Connect

    Woloshun, Keith Albert; Dale, Gregory E.; Olivas, Eric Richard; Naranjo, Angela Carol; Romero, Frank Patrick

    2016-08-15

    The Northstar target for Mo99 production is made up of Mo100 disks in a stack separated by coolant gaps for helium flow. A number of targets have been tested at ANL for both production of Mo99 and for thermal-hydraulic performance. These have all been with a 12 mm diameter target, even while the production goals have increased the diameter to now 29 mm. A 29 mm diameter target has been designed that is consistent with the ANL beam capabilities and the capabilities of the helium circulation system currently in use at ANL. This target is designed for 500 μA at 35 MeV electrons. While the plant design calls for 42 MeV, the chosen design point is more favorable and higher power given the limits of the ANL accelerator. The intended beam spot size is 12 mm FWHM, but the thermal analysis presented herein conservatively assumed a 10 mm FWHM beam, which results in a 44% higher beam current density at beam center.

  3. Process of [sup 196]Hg enrichment

    DOEpatents

    Grossman, M.W.; Mellor, C.E.

    1993-04-27

    A simple rate equation model shows that by increasing the length of the photochemical reactor and/or by increasing the photon intensity in said reactor, the feedstock utilization of [sup 196]Hg will be increased. Two preferred embodiments of the present invention are described, namely (1) long reactors using long photochemical lamps and vapor filters; and (2) quartz reactors with external UV reflecting films. These embodiments have each been constructed and operated, demonstrating the enhanced utilization process dictated by the mathematical model (also provided).

  4. Process of .sup.196 Hg enrichment

    DOEpatents

    Grossman, Mark W.; Mellor, Charles E.

    1993-01-01

    A simple rate equation model shows that by increasing the length of the photochemical reactor and/or by increasing the photon intensity in said reactor, the feedstock utilization of .sup.196 Hg will be increased. Two preferred embodiments of the present invention are described, namely (1) long reactors using long photochemical lamps and vapor filters; and (2) quartz reactors with external UV reflecting films. These embodiments have each been constructed and operated, demonstrating the enhanced utilization process dictated by the mathematical model (also provided).

  5. Laparoscopic cholecystectomy using 2-mm instruments.

    PubMed

    Uranüs, S; Peng, Z; Kronberger, L; Pfeifer, J; Salehi, B

    1998-10-01

    Today, laparoscopic cholecystectomy is the method of choice for treatment of symptomatic gallbladder disorders. It minimizes effects of the operation that are independent of the gallbladder, such as trauma to the abdominal wall and other soft tissue. The surgical wounds were even smaller when 2-mm trocars were used. Laparoscopic cholecystectomy using 2-mm instruments was performed in a consecutive series of 14 patients with symptomatic gallstones. The procedure was completed in 12 cases, with conversion to open surgery in two cases. Intraoperative cholangiography was always performed. The postoperative course was always uneventful. The cosmetic effect was highly satisfactory. The procedure using 2-mm instruments could be indicated in selected patients with uncomplicated gallstone disease.

  6. HgZnTe-based detectors for LWIR NASA applications

    NASA Technical Reports Server (NTRS)

    Patten, Elizabeth A.; Kalisher, Murray H.

    1990-01-01

    The initial goal was to grow and characterize HgZnTe and determine if it indeed had the advantageous properties that were predicted. Researchers grew both bulk and liquid phase epitaxial HgZnTe. It was determined that HgZnTe had the following properties: (1) microhardness at least 50 percent greater than HgCdTe of equivalent bandgap; (2) Hg annealing rates of at least 2 to 4 times longer than HgCdTe; and (3) higher Hg vacancy formation energies. This early work did not focus on one specific composition (x-value) of HgZnTe since NASA was interested in HgZnTe's potential for a variety of applications. Since the beginning of 1989, researchers have been concentrating, however, on the liquid phase growth of very long wavelength infrared (VLWIR) HgZnTe (cutoff approx. equals 17 microns at 65K) to address the requirements of the Earth Observing System (EOS). Since there are no device models to predict the advantages in reliability one can gain with increased microhardness, surface stability, etc., one must fabricate HgZnTe detectors and assess their relative bake stability (accelerated life test behavior) compared with HgCdTe devices fabricated in the same manner. Researchers chose to fabricate HIT detectors as a development vehicle for this program because high performance in the VLWIR has been demonstrated with HgCdTe HIT detectors and the HgCdTe HIT process should be applicable to HgZnTe. HIT detectors have a significant advantage for satellite applications since these devices dissipate much less power than conventional photoconductors to achieve the same responsivity.

  7. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  8. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  9. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  10. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  11. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  12. The Chevrel phase HgMo6S8

    PubMed Central

    Salloum, Diala; Gougeon, Patrick; Potel, Michel

    2009-01-01

    The crystal structure of HgMo6S8, mercury(II) hexa­molybdenum octa­sulfide, is based on (Mo6S8)S6 cluster units ( symmetry) inter­connected through inter­unit Mo—S bonds. The Hg2+ cations occupy large voids between the different cluster units and are covalently bonded to two S atoms. The Hg atoms and one S atom lie on sites with crystallographic and 3 symmetry, respectively. Refinement of the occupancy factor of the Hg atom led to the composition Hg0.973 (3)Mo6S8. PMID:21583726

  13. A synthetic model of Hg(II) sequestration.

    PubMed

    Viehweg, Julie A; Stamps, Sarah M; Dertinger, Jennifer J; Green, Robert L; Harris, Katherine E; Butcher, Raymond J; Andriole, Erica J; Poutsma, J C; Berry, Steven M; Bebout, Deborah C

    2010-04-07

    Tridentate ligand N-(2-pyridylmethyl)-N-(2-(ethylthiolato)amine (L) forms the novel complex [Hg(5)(L)(6)](ClO(4))(4).toluene () with a bicyclo[3.3.3] Hg(5)S(6) core and 4-, 5- and 6-coordinate metal centers; characterization of a solution of by ESI-MS revealed elaborate speciation involving [Hg(n)L(n+1)(ClO(4))(n-2)](+), [Hg(n)L(n)(ClO(4))(n-1)](+) and [Hg(n)L(n-1)(ClO(4))(n)](+) ion families.

  14. Hg Isotope Ratios of a Sediment Core from Plastic Lake, Ontario: Implications for Hg Cycle in Aquatic Environment

    NASA Astrophysics Data System (ADS)

    Xie, Q.; Dillon, P.; Evans, D.; Lu, S.

    2004-12-01

    Hg isotope ratios in a sediment core obtained in Plastic Lake, Ontario, Canada, have been measured by coupling a gold trap with an MC-ICP-MS. The core is about 30 cm in depth and corresponds to a time period of about 250 years, based on 210Pb dating. The samples were combusted at high temperature and the Hg collected onto a gold trap. The gold trap was subsequently heated to release Hg directly into the MC-ICP-MS. An in-house sample introduction system was employed to extend Hg signal duration in order to obtain high precision in isotope ratio measurement. The instrumental mass bias was corrected using Tl introduced simultaneously via an Aridus membrane desolvation nebulizer. Based on long term measurement of a NIST-2225 elemental Hg standard (over 120 measurements since Oct. 2002), the external reproducibility ranges from 45 ppm for 201Hg/202Hg to 100 ppm for 199Hg/202Hg (2 sigma relative standard error). Hg in the sediments shows an increase in light isotope enrichment at about 10 cm depth. The total Hg also displays an increase at the same depth. The depth corresponds to approximately the 1920s, a time period when there was a major increase in coal-burning power generation. Limited Hg isotope data for other terrestrial samples appears to indicate that Hg bound to organic carbon is enriched in light isotopes relative to elemental Hg. For example, the DOLT-3, a dogfish liver standard reference material with half of its Hg as MeHg, has the lightest Hg isotope composition among measured terrestrial samples. It is not clear at this stage whether the increase in total Hg and light Hg isotope enrichment in recent years represent a change in methylation rate of the lake, or an increase in atmospheric deposition of Hg combined with a change in source. Discussions based on available Hg isotope data of terrestrial samples together with other chemical data for the lake will be presented.

  15. Heavy metal tolerance (Cr, Ag AND Hg) in bacteria isolated from sewage

    PubMed Central

    Lima de Silva, Agostinho A.; de Carvalho, Márcia A. Ribeiro; de Souza, Sérgio A. L; Dias, Patrícia M. Teixeira; da Silva Filho, Renato G.; de Meirelles Saramago, Carmen S.; de Melo Bento, Cleonice A.; Hofer, Ernesto

    2012-01-01

    Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr), silver (Ag) and mercury (Hg). Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%). Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerant Bacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr). Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria. PMID:24031994

  16. Bioindication of volcanic mercury (Hg) deposition around Mt Etna (Sicily)

    NASA Astrophysics Data System (ADS)

    Martin, R.; Witt, M. L.; Sawyer, G. M.; Watt, S.; Bagnato, E.; Calabrese, S.; Aiuppa, A.; Delmelle, P.; Pyle, D. M.; Mather, T. A.

    2012-12-01

    Mt. Etna is a major natural source of Hg to the Mediterranean region. Total mercury concentrations, [Hg]tot, in Castanea sativa (sweet chestnut) leaves sampled 7-13 km from Etna's vents (during six campaigns in 2005-2011) were determined using atomic absorption spectroscopy. [Hg]tot in C. sativa was greatest on Etna's SE flank reflecting Hg deposition from the typically overhead volcanic plume. When adjusted for leaf age, [Hg]tot in C. sativa also increased with recent eruptive activity. [Hg]tot in C. sativa was not controlled by [Hg]tot in soils, which instead was greatest on the (upwind) NW flank and correlated strongly with soil organic matter (% Org). Our results suggest that at least ~1% of Hg emitted from Etna is deposited proximally, supporting recent measurement and model results which indicate that GEM (Hg0; the dominant form of Hg in high temperature magmatic gases) is oxidised rapidly to RGM and Hgp in ambient temperature volcanic plumes. Samples of C. sativa and soils were also collected in July and September 2012 alongside SO2 and acid gas diffusion tube samples. These new samples will enable us to investigate Hg accumulation over a single growth season with reference to the exposure of vegetation to volcanic gases and particles.

  17. Littoral Combat Ship Mission Modules (LCS MM)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-443 Littoral Combat Ship Mission Modules (LCS MM) As of FY 2017 President’s Budget Defense...Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined TY

  18. Excalibur Precision 155mm Projectiles (Excalibur)

    DTIC Science & Technology

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-366 Excalibur Precision 155mm Projectiles (Excalibur) As of FY 2017 President’s Budget...Program Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be

  19. Optimizing digital 8mm drive performance

    NASA Technical Reports Server (NTRS)

    Schadegg, Gerry

    1993-01-01

    The experience of attaching over 350,000 digital 8mm drives to 85-plus system platforms has uncovered many factors which can reduce cartridge capacity or drive throughput, reduce reliability, affect cartridge archivability and actually shorten drive life. Some are unique to an installation. Others result from how the system is set up to talk to the drive. Many stem from how applications use the drive, the work load that's present, the kind of media used and, very important, the kind of cleaning program in place. Digital 8mm drives record data at densities that rival those of disk technology. Even with technology this advanced, they are extremely robust and, given proper usage, care and media, should reward the user with a long productive life. The 8mm drive will give its best performance using high-quality 'data grade' media. Even though it costs more, good 'data grade' media can sustain the reliability and rigorous needs of a data storage environment and, with proper care, give users an archival life of 30 years or more. Various factors, taken individually, may not necessarily produce performance or reliability problems. Taken in combination, their effects can compound, resulting in rapid reductions in a drive's serviceable life, cartridge capacity, or drive performance. The key to managing media is determining the importance one places upon their recorded data and, subsequently, setting media usage guidelines that can deliver data reliability. Various options one can implement to optimize digital 8mm drive performance are explored.

  20. Mm-wave power meter mount

    NASA Technical Reports Server (NTRS)

    Mullen, D. L.; Oltmans, D. A.; Stelzried, C. T.

    1968-01-01

    E-band thermistor mount and a technique for adjusting a temperature compensating thermistor to provide an electrically balanced bridge are used for measuring RF power in the mm-wavelength. The mount is relatively insensitive to temperature effects that cause measurement errors in single ended circuits.

  1. MM-122: High speed civil transport

    NASA Technical Reports Server (NTRS)

    Demarest, Bill; Anders, Kurt; Manchec, John; Yang, Eric; Overgaard, Dan; Kalkwarf, Mike

    1992-01-01

    The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

  2. CCM3 to MM5 Data Conversion

    SciTech Connect

    Taylor, John; Mirin, Arthur

    2007-03-02

    The accompanying script (which uses the NCAR Command Language) ready output from the Community Climate Model Code, version 3 (CCM3) and converts it to input format for the Mesoscale Model, version 5 (MM5) code. The script utilizes a Fortran binary write routine.

  3. Thermodynamic assessment of Hg(II)-gibbsite interactions.

    PubMed

    Weerasooriya, Rohan; Seneviratne, Wasana; Kathriarachchi, Heasha A; Tobschall, Heinz J

    2006-09-15

    As discrete particles and/or as surface coatings on other minerals in natural systems, aluminum hydroxides are efficient sinks for Hg(II). The Hg(II) adsorption on gibbsite was determined as a function of temperature (T), pH, and the type of background electrolytes, i.e., NaNO(3), NaClO(4), and NaCl. When the equilibration time t(E) approximately 2 h, the Hg(II) retention on gibbsite was found to be a reversible process, which was ascribed to adsorption. The Hg(II) adsorption capacity, i.e., Gamma(Hg(II)), varied with the type of electrolyte used in accordance with the following order: Gamma(NO(3))(Hg(II)) > or = Gamma(ClO(4))(Hg(II)) > or = Gamma(Cl)(Hg(II)). In all cases, the estimated thermodynamic parameters showed that the Hg(II) adsorption on gibbsite was endothermic and spontaneous. The Hg(II) adsorption data were quantified with the Langmuir or Hill, and Dublin-Radushkevick (DR), isotherms at all temperatures and acidity levels examined. Always, the Hg(II) adsorption data were in compliance with the DR model. However, the Hg(II) adsorption in NaNO(3) or NaClO(4) was interpreted in terms of the Langmuir model. When NaCl was used as electrolyte, the Hg(II) adsorption was modeled well with the Hill equation. The mean free energy values calculated from DR plots concluded that Hg(II)-gibbsite interactions are a result of chemical bonding.

  4. Stable mercury isotope ratios as tracers for Hg cycling at the inoperative New Idria Hg mine, California

    NASA Astrophysics Data System (ADS)

    Wiederhold, J. G.; Jew, A. D.; Brown, G. E.; Bourdon, B.; Kretzschmar, R.

    2010-12-01

    The seven stable isotopes of Hg are fractionated in the environment as a result of mass-dependent (MDF) and mass-independent (MIF) fractionation processes that can be studied in parallel by analyzing the ratios of even and odd mass Hg isotopes. MDF and MIF Hg isotope signatures of natural samples may provide a new tool to trace sources and transformations in environmental Hg cycling. However, the mechanisms controlling the extent of kinetic and equilibrium Hg isotope fractionations are still only partially understood. Thus, development of this promising tracer requires experimental calibration of relevant fractionation factors as well as assessment of natural variations of Hg isotope ratios under different environmental conditions. The inoperative Hg mine in New Idria (California, USA) represents an ideal case study to explore Hg isotope fractionation during Hg transformation and transport processes. More than a century of Hg mining and on-site thermal refining to obtain elemental Hg until 1972 produced large volumes of contaminated mine wastes which now represent sources of Hg pollution for the surrounding ecosystems. Here, we present Hg isotope data from various materials collected at New Idria using Cold-Vapor-MC-ICPMS with a long-term δ202Hg reproducibility of ±0.1‰ (2SD). Uncalcined mine waste samples were isotopically similar to NIST-3133 and did not exhibit any MIF signatures. In contrast, calcine samples, which represent the residue of the thermal ore processing at 700°C, had significantly heavier δ202Hg values of up to +1.5‰. In addition, we observed small negative MIF anomalies of the odd-mass Hg isotopes in the calcine samples, which could be caused either by nuclear volume fractionation or a magnetic isotope effect during or after the roasting process. The mass-dependent enrichment of heavy Hg isotopes in the calcine materials indicates that light Hg isotopes were preferentially removed during the roasting process, in agreement with a previous

  5. STS-80 Onboard Photograph

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This STS-80 onboard photograph shows the Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer-Shuttle Pallet Satellite II (ORFEUS-SPAS II), photographed during approach by the Space Shuttle Orbiter Columbia for retrieval. Built by the German Space Agency, DARA, the ORFEUS-SPAS II, a free-flying satellite, was dedicated to astronomical observations at very short wavelengths to: investigate the nature of hot stellar atmospheres, investigate the cooling mechanisms of white dwarf stars, determine the nature of accretion disks around collapsed stars, investigate supernova remnants, and investigate the interstellar medium and potential star-forming regions. Some 422 observations of almost 150 astronomical objects were completed, including the Moon, nearby stars, distant Milky Way stars, stars in other galaxies, active galaxies, and quasar 3C273. The STS-80 mission was launched November 19, 1996.

  6. AQUEOUS REDUCTION OF HG2+ TO HG0 BY HO2 IN THE CMAQ-MODEL

    EPA Science Inventory

    Numerical models of atmospheric mercury are formulated based on the current understanding of mercury chemistry in air and in atmospheric water. Recent evidence that significant reduction of Hg2+ by reaction with HO2 may not actually occur in natural atmospheric water has obviou...

  7. Mass Independent Fractionation of Hg Isotopes Preserved in the Precambrian

    NASA Astrophysics Data System (ADS)

    Thibodeau, A. M.; Bergquist, B. A.; Kah, L. C.; Ono, S.; Ghosh, S.; Hazen, R. M.

    2013-12-01

    Mercury (Hg) is a photochemically active, redox-sensitive, chalcophilic metal with complex biogeochemistry that displays a wide range of mass-dependent (MDF) and mass-independent (MIF) stable isotopic fractionation. In the past decade, Hg isotopes have emerged as important tracers of both the sources and cycling of Hg in the modern environment. However, their utility as environmental proxies in ancient rocks remains largely unexplored. The potential of Hg isotopes to inform Precambrian environments derives from the observation that Hg isotopes with odd atomic mass numbers (199Hg and 201Hg) undergo large MIF by the magnetic isotope effect (MIE) and smaller MIF through the nuclear volume effect (NVE). Small MIF produced via NVE has been observed for numerous transformations and is characterized by MIF ratios (Δ199Hg/Δ201Hg) of about 1.6. Large Hg-MIF driven by MIE has been observed during photochemical transformations and is characterized by Δ199Hg/Δ201Hg ratios between 1 and 1.3. This MIF signal is sensitive to a range of environmental conditions, including the amount and type of solar radiation, the presence and type of complexing organic ligands, and the Hg/dissolved organic carbon (DOC) ratio. Thus, it is hoped that Hg-MIF signals may indirectly record changes in atmospheric composition or seawater chemistry if preserved in marine sedimentary records. Previous work has clearly demonstrated that Hg-MIF signals are preserved in Archean and Paleoproterozoic marine shales and massive sulfide deposits. Here, we present evidence that such signals are also preserved in marine shales of mid-Proterozoic age, including the ~1.3 Ga Sulky formation (Dismal Lakes Group, NW Arctic), the ~1.45 Ga Greyson Shale (Belt Basin, Montana), and the ~1.5 Ga Katalsy formation (Kypry Group, Eastern European Platform). We observe that the Greyson shale and shales within the Sulky formation yield negative Hg-MIF with Δ199Hg/Δ201Hg ratios close to 1 and that Kaltasy group sediments

  8. Dissecting the effect of anions on Hg2+ detection using a FRET based DNA probe.

    PubMed

    Kiy, Mehmet Murat; Zaki, Ahmed; Menhaj, Arsalsan Beg; Samadi, Azadeh; Liu, Juewen

    2012-08-07

    Many biosensors have been developed to detect Hg(2+) using thymine-rich DNA. While sensor response to various cations is often studied to demonstrate selectivity, the effect of anions has been largely overlooked. Anions may compete with DNA for metal binding and thus produce a false negative result. Anions cannot be added alone; the cation part of a salt may cause DNA compaction and other effects, obscuring the role of anions. We find that the sensitivity of a FRET-based Hg(2+) probe is independent of Na(+) concentration. Therefore, by using various sodium salts, any change in sensitivity can be attributed solely to the effect of anions. Halide salts, sulfides, and amines are strong inhibitors; anions containing oxo or hydroxyl groups (e.g. nitrate, sulfate, phosphate, carbonate, acetate, and citrate) do not interfere with Hg(2+) detection even at 100 mM concentration. Mercury hydrolysis and its diffusion into polypropylene containers can also strongly affect the detection results. We conclude that thymine-rich DNA should be useful for Hg(2+) detection in many environmental water samples.

  9. Reactive iron sulfide (FeS)-supported ultrafiltration for removal of mercury (Hg(II)) from water.

    PubMed

    Han, Dong Suk; Orillano, Maria; Khodary, Ahmed; Duan, Yuhang; Batchelor, Bill; Abdel-Wahab, Ahmed

    2014-04-15

    This study investigated removal of Hg(II) from water using FeS(s) with batch and continuous contact filtration systems. For the batch system, kinetic experiments showed that removal of Hg(II) by FeS(s) was rapid at lower concentration (500 μM), but at higher concentration (1000 and 1250 μM), more time was required to achieve greater than 99% removal. The concentration of iron released to the solution remained relatively low, typically below 3 μM. This would theoretically present less than 1% of the Hg(II) removed. Thus, a simple exchange of Hg(II) for Fe(II) in the solid (FeS(s)) does not explain the results, but if the Fe(II) released could react to form another solids, low concentrations of Fe do not preclude a mechanism in which Hg(II) reacts to form HgS and release Fe(II). A continuous contact dead-end ultrafiltration (DE/UF) system was developed to treat water containing Hg(II) by applying a FeS(s) suspension with stirred or non-stirred modes. A major reason for applying stirring to the system was to investigate the role of "shear" flow in rejection of Hg(II)-contacted FeS(s) by a UF membrane and the stability of Hg on the FeS(s). The Hg(II)-contacted FeS(s) was completely rejected by the DE/UF system and mercury was strongly retained on the FeS(s) particles. Almost no release of Hg(II) (≈0 mM) from the FeS(s) solids was observed when they were contacted with 0.1M-thiosulfate, regardless of whether the system was operated in stirred or non-stirred mode. However, rapid oxidation of FeS(s) was observed in the stirred system but not in the non-stirred system. Determining the mechanism of oxidation requires further study, but it is important because oxidation reduces the ability of the solids to remove additional Hg(II).

  10. MicroCT vs. Hg porosimetry: microporosity in commercial stones

    NASA Astrophysics Data System (ADS)

    Fusi, N.; Martinez-Martinez, J.; Barberini, V.; Galimberti, L.

    2009-04-01

    Decay of rocks, due both to extrinsic and intrinsic factors, can show up in several different forms, such as neoformation of minerals, decohesion of grains and/or crystals, magnification of previous defects, new discontinuities, etc. Intrinsic factors include the type of material, its properties and microstructure, in particular porosity and microporosity. Extrinsic factors relate to atmosphere and usage of the material itself. Rock degradation has several heavy consequences for commercial stones, such as increase of permeability, loss of material, loss of mechanical strength; these consequences are of crucial importance for conservation of historical buildings. Aim of this study is to compare microporosity of some massive commercial stones by means of X ray microtomography, a non destructive technique, and Hg porosimetry. Nine of the most used Spanish limestones and dolostones have been analysed. The lithotypes have been chosen for their homogeneous mineralogical composition (calcitic or dolomitic) and for their low porosity; some of them have been widely used in Spain for historical buildings. Different lithotypes have been described in thin section: Ambarino (A) and Beige Serpiente (BS): brecciated dolostone, composed by microcrystalline dolomitic clasts, in a dolomitic and/or calcitic microcrystalline matrix. Amarillo Triana (AT): yellow dolomitic marble, with fissures filled up by calcite and Fe oxides. Blanco Alconera (BA): a white-pink homogeneous limestone, with veins. Blanco Tranco (BT): a homogeneous white calcitic marble, without any fissures and/or fractures. Crema Valencia (CV): a pinkish limestone, characterized by abundant stilolythes, filled mainly by quartz (80%) and kaolin (11%). Gris Macael (GM): a calcitic marble wiht darker and lighter beds, conferring a strong anisotropy. Rojo Cehegin (RC): a red fossiliferous limestone with white calcitic veins. Travertino Blanco (TB): a massive white calcitic travertine. Prismatic samples of about 2x1x1 cm

  11. Evidence for CVD 103-HgR as an effective single-dose oral cholera vaccine.

    PubMed

    Jackson, Sarah S; Chen, Wilbur H

    2015-01-01

    We propose the ideal oral cholera vaccine (OCV) should be an inexpensive, single, oral dose that rapidly confers immunity for a long duration, and is well tolerated by individuals vulnerable to cholera. Vaccine trials in industrialized countries of a single oral dose of 5 × 10(8) colony forming units (CFU) of the live, attenuated cholera strain CVD 103-HgR have shown 88-97% serum vibriocidal antibody seroconversion rates, a correlate of protection and documented vaccine efficacy of ≥80% using volunteer challenge studies with wild-type cholera. For individuals of developing countries, a 5 × 10(9) CFU dose of CVD 103-HgR is necessary to elicit similar antibody responses. Presently, a reformulation of CVD 103-HgR is in late-stage clinical development for prospective US FDA licensure; making a cholera vaccine for US travelers potentially accessible in 2016. The availability of CVD 103-HgR should be a welcome addition to the currently available OCVs.

  12. Modeling of HgCdTe focal plane array spectral inhomogeneities

    NASA Astrophysics Data System (ADS)

    Mouzali, Salima; Lefebvre, Sidonie; Rommeluère, Sylvain; Ferrec, Yann; Primot, Jérôme

    2015-06-01

    Infrared focal plane arrays (IRFPA) are widely used to perform high quality measurements such as spectrum acquisition at high rate, ballistic missile defense, gas detection, and hyperspectral imaging. For these applications, the fixed pattern noise represents one of the major limiting factors of the array performance. This sensor imperfection refers to the nonuniformity between pixels, and is partially caused by disparities of the cut-off wavenumbers. In this work, we focus particularly on mercury cadmium telluride (HgCdTe), which is the most important material of IR cooled detector applications. Among the many advantages of this ternary alloy is the tunability of the bandgap energy with Cadmium composition, as well as the high quantum efficiency. In order to predict and understand spectral inhomogeneities of HgCdTe-based IRFPA, we propose a modeling approach based on the description of optical phenomena inside the pixels. The model considers the p-n junctions as a unique absorbent bulk layer, and derives the sensitivity of the global structure to both Cadmium composition and HgCdTe layer thickness. For this purpose, HgCdTe optical and material properties were necessary to be known at low temperature (80K), in our operating conditions. We therefore achieved the calculation of the real part of the refractive index using subtracti

  13. Revealing the origin of the efficiency of the de novo designed Kemp eliminase HG-3.17 by comparison with the former developed HG-3.

    PubMed

    Moliner, Vicent; Swiderek, Katarzyna; Tuñón, Iñaki; Bertran, Joan

    2017-03-23

    The design of new biocatalysts is a goal in biotechnology to improve the rate, selectivity and environmental impact of industrial chemical processes. In this regard, the use of computational techniques has provided valuable assistance in the design of new enzymes with remarkable catalytic activity. In this paper, hybrid QM/MM Molecular Dynamics simulations have allowed getting an insight into the origin of the limited efficiency of a computationally designed enzyme for the Kemp elimination; the HG-3. Comparison of results derived from this enzyme with those of a more evolved protein containing additional point mutations, HG-3.17, rendered important information to take into account in order to design new enzymes. For this Kemp eliminase reaction, larger reactivity has been demonstrated to be related with a better electrostatic preorganization of the environment that creates a more favourable electrostatic potential for the reaction to proceed. The limitations of HG-3 can be related with a lack of flexibility, a not well fitted active site, and a lack of protein electrostatic preorganization that decrease the reorganization around the oxyanion hole.

  14. Superdeformation studies in {sup 191}Hg

    SciTech Connect

    Carpenter, M.P.; Janssens, R.V.F.; Crowell, B.

    1995-08-01

    Superdeformation in the A {approximately} 190 region was first observed in {sup 191}Hg from an experiment performed at ATLAS using the Argonne Notre Dame {gamma}-ray facility. We recently revisited the study of superdeformation in this nucleus using Gammasphere and the {sup 160}Gd({sup 36}S,5n) and {sup 174}Yb({sup 22}Ne,5n) reactions at 172 and 120 MeV in order to populate and measure states in the second well. The goal of the experiment was to identify new bands in the data, and thus allow us to gain understanding on the relative placement of single particle orbitals near the N = 112 SD shell gap. From an analysis of the data, the three previously identified SD bands were extended, and their feeding into the yrast states delineated. Two new SD bands were observed and preliminary evidence for a third new band was obtained as well.

  15. Coaxial HgI excimer lamps

    SciTech Connect

    Malinin, A N; Polyak, A V; Guivan, N N; Shimon, Lyudvik L; Zubrilin, N G

    2002-02-28

    The emission of coaxial HgI excimer lamps pumped by a repetitively pulsed barrier discharge is experimentally studied. The stable operation of the excimer lamps was demonstrated at pump-pulse repetition rates from 0.5 to 12 kHz, and the average emission power attained of 0.6 W at 444 nm. It was found that upon an addition of 0.8% of xenon to the mixture of helium and mercury diiodide, the pulse and average emission powers increased by 30%. The emission power reduced by 5% after 2.5 x 10{sup 6} pulses. An interpretation of the results of optimising the excimer lamp characteristics is given. (laser applications and other topics in quantum electronics)

  16. Biotransformation of Hg(II) by Cyanobacteria▿ †

    PubMed Central

    Lefebvre, Daniel D.; Kelly, David; Budd, Kenneth

    2007-01-01

    The biotransformation of Hg(II) by cyanobacteria was investigated under aerobic and pH-controlled culture conditions. Mercury was supplied as HgCl2 in amounts emulating those found under heavily impacted environmental conditions where bioremediation would be appropriate. The analytical procedures used to measure mercury within the culture solution, including that in the cyanobacterial cells, used reduction under both acid and alkaline conditions in the presence of SnCl2. Acid reduction detected free Hg(II) ions and its complexes, whereas alkaline reduction revealed that meta-cinnabar (β-HgS) constituted the major biotransformed and cellularly associated mercury pool. This was true for all investigated species of cyanobacteria: Limnothrix planctonica (Lemm.), Synechococcus leopoldiensis (Racib.) Komarek, and Phormidium limnetica (Lemm.). From the outset of mercury exposure, there was rapid synthesis of β-HgS and Hg(0); however, the production rate for the latter decreased quickly. Inhibitory studies using dimethylfumarate and iodoacetamide to modify intra- and extracellular thiols, respectively, revealed that the former thiol pool was required for the conversion of Hg(II) into β-HgS. In addition, increasing the temperature enhanced the amount of β-HgS produced, with a concomitant decrease in Hg(0) volatilization. These findings suggest that in the environment, cyanobacteria at the air-water interface could act to convert substantial amounts of Hg(II) into β-HgS. Furthermore, the efficiency of conversion into β-HgS by cyanobacteria may lead to the development of applications in the bioremediation of mercury. PMID:17071784

  17. Terahertz/mm wave imaging simulation software

    NASA Astrophysics Data System (ADS)

    Fetterman, M. R.; Dougherty, J.; Kiser, W. L., Jr.

    2006-10-01

    We have developed a mm wave/terahertz imaging simulation package from COTS graphic software and custom MATLAB code. In this scheme, a commercial ray-tracing package was used to simulate the emission and reflections of radiation from scenes incorporating highly realistic imagery. Accurate material properties were assigned to objects in the scenes, with values obtained from the literature, and from our own terahertz spectroscopy measurements. The images were then post-processed with custom Matlab code to include the blur introduced by the imaging system and noise levels arising from system electronics and detector noise. The Matlab code was also used to simulate the effect of fog, an important aspect for mm wave imaging systems. Several types of image scenes were evaluated, including bar targets, contrast detail targets, a person in a portal screening situation, and a sailboat on the open ocean. The images produced by this simulation are currently being used as guidance for a 94 GHz passive mm wave imaging system, but have broad applicability for frequencies extending into the terahertz region.

  18. Spectroscopic Performance of Thick HgI2 Detectors

    PubMed Central

    Meng, L. J.; He, Z.; Alexander, B.; Sandoval, J.

    2016-01-01

    This paper presents the spectroscopic performance of two newly developed pixelated HgI2 detectors. These detectors are 1 × 1 × 0.814 cm3 and 1 × 1 × 1.016 cm3 in size. Each detector has four closely packed 1 × mm2 anode pixels at the center of one of the 1 × 1 cm2 surfaces. These anode pixels are surrounded by a large anode. All results presented here are based on events from a sub-volume underneath the anode pixels. In these detectors, signals were read out by a discrete electronics based on multiple A-250 pre-amplifiers and a digital oscilloscope for sampling pulse waveforms. Depth sensing technique was used to correct the depth-dependent variation in photopeak amplitude. Main results presented are: (1) energy resolutions of 0.85 ~ 1.3% have been achieved on these detectors; (2) the electron mobility-lifetime product was measured to be ~1 × 10−2 cm2/V and the measured electron lifetime was ~200 μs and (3) variation in electron drifting properties under different anode pixels were observed. Significant non-uniformity in internal electric field strength was also experimentally demonstrated. PMID:28250474

  19. VLA 7-mm Observations of Massive Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik; Hofner, Peter; Araya, Esteban; Stecklum, Bringfried

    2003-07-01

    follow-up observations with higher resolution. For the majority of our sample targets we have revealed pronounced 7-mm emission. Especially interesting is G31.41+0.31 where we could resolve the 7-mm emission arising from a so-called hot molecular core. For GGD27, we found the 7-mm counterpart of the object that illuminates this region in the near-infrared and that also acts as the driving source of the associated outflow system HH80/81. Consequently, this detection establishes GGD27 as a key candidate regarding the search for an accretion disk around a forming high-mass star. Furthermore, we demonstrate some synergy effects between radio and infrared data concerning the interpretation of the nature of those very young massive stars. H.L. and B.S. are supported by DFG grant Ste 605/17-2. P.H. acknowledges partial support from the Research Corporation grant No CC4996, as well as from NSF grant AST-0098524.

  20. Developing a genetically encoded green fluorescent protein mutant for sensitive light-up fluorescent sensing and cellular imaging of Hg(II).

    PubMed

    Jiang, Tao; Guo, Daiping; Wang, Qian; Wu, Xin; Li, Zhao; Zheng, Zhenhua; Yin, Boyuan; Xia, Lin; Tang, Jixian; Luo, Wenxin; Xia, Ningshao; Jiang, Yunbao

    2015-05-30

    Hg(II) is well-known for quenching fluorescence in a distance dependent manner. Nevertheless, when we exposed the fluorophore of a green fluorescent protein (GFP) toward Hg(II), through H148C mutation, the GFP fluorescence could be "lighted up" by Hg(II) down to sub-nM level. The detection linear range is 0.5-3.0 nM for protein solutions at 8.0 nM. The GFPH148C protein displayed a promising selectivity toward Hg(II) and also the cellular imaging capacity. Spectra measurements suggested that the ground-state redistribution of protein contributed to the fluorescence enhancement, which was found not limited to Hg(II), and thus presented an opening for building a pool of GFP-based chemosensors toward other heavy metal ions.

  1. 40 CFR 80.537-80.539 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.537-80.539 Section 80.537-80.539 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  2. 40 CFR 80.556-80.559 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.556-80.559 Section 80.556-80.559 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  3. 40 CFR 80.587-80.589 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.587-80.589 Section 80.587-80.589 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  4. 40 CFR 80.503-80.509 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.503-80.509 Section 80.503-80.509 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  5. 40 CFR 80.562-80.569 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.562-80.569 Section 80.562-80.569 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  6. 40 CFR 80.575-80.579 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.575-80.579 Section 80.575-80.579 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  7. 40 CFR 80.541-80.549 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false 80.541-80.549 Section 80.541-80.549 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and...

  8. 47 CFR 80.80 - Operating controls for ship stations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Operating controls for ship stations. 80.80... SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Station Requirements-Ship Stations § 80.80 Operating controls for ship stations. (a) Each control point must be capable of:...

  9. 47 CFR 80.80 - Operating controls for ship stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Operating controls for ship stations. 80.80... SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Station Requirements-Ship Stations § 80.80 Operating controls for ship stations. (a) Each control point must be capable of:...

  10. 47 CFR 80.80 - Operating controls for ship stations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Operating controls for ship stations. 80.80... SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Station Requirements-Ship Stations § 80.80 Operating controls for ship stations. (a) Each control point must be capable of:...

  11. 47 CFR 80.80 - Operating controls for ship stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Operating controls for ship stations. 80.80... SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Station Requirements-Ship Stations § 80.80 Operating controls for ship stations. (a) Each control point must be capable of:...

  12. 47 CFR 80.80 - Operating controls for ship stations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operating controls for ship stations. 80.80... SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Station Requirements-Ship Stations § 80.80 Operating controls for ship stations. (a) Each control point must be capable of:...

  13. A dansyl based fluorescence chemosensor for Hg2+ and its application in the complicated environment samples

    NASA Astrophysics Data System (ADS)

    Zhou, Shuai; Zhou, Ze-Quan; Zhao, Xuan-Xuan; Xiao, Yu-Hao; Xi, Gang; Liu, Jin-Ting; Zhao, Bao-Xiang

    2015-09-01

    We have developed a novel fluorescent chemosensor (DAM) based on dansyl and morpholine units for the detection of mercury ion with excellent selectivity and sensitivity. In the presence of Hg2+ in a mixture solution of HEPES buffer (pH 7.5, 20 mM) and MeCN (2/8, v/v) at room temperature, the fluorescence of DAM was almost completely quenched from green to colorless with fast response time. Moreover, DAM also showed its excellent anti-interference capability even in the presence of large amount of interfering ions. It is worth noting that DAM could be used to detect Hg2+ specifically in the Yellow River samples, which significantly implied the potential applications of DAM in the complicated environment samples.

  14. HgCdTe heterostructures on Si (310) substrates for midinfrared focal plane arrays

    SciTech Connect

    Yakushev, M. V. Brunev, D. V.; Varavin, V. S.; Vasilyev, V. V.; Dvoretskii, S. A.; Marchishin, I. V.; Predein, A. V.; Sabinina, I. V.; Sidorov, Yu. G.; Sorochkin, A. V.

    2011-03-15

    Results of studies of the molecular beam epitaxial growth of HgCdTe alloys on Si substrates as large as 100 mm in diameter are presented. Optimum conditions for obtaining HgCdTe/Si(310) heterostructures of the device quality for the spectral range of 3-5 {mu}m are determined. The results of measurements and discussion of photoelectric parameters of an infrared photodetector of a format of 320 Multiplication-Sign 256 elements with a step of 30 {mu}m based on a hybrid assembly of a matrix photosensitive cell with a Si multiplexer are presented. A high stability of photodetector parameters to thermocycling from room temperature to liquid-nitrogen temperature is shown.

  15. Ruditapes philippinarum and Ruditapes decussatus under Hg environmental contamination.

    PubMed

    Velez, Cátia; Galvão, Petrus; Longo, Renan; Malm, Olaf; Soares, Amadeu M V M; Figueira, Etelvina; Freitas, Rosa

    2015-08-01

    The native species Ruditapes decussatus and the invasive species Ruditapes philippinarum have an important ecological role and socio-economic value, from the Atlantic and Mediterranean to the Indo-Pacific region. In the aquatic environment, they are subjected to the presence of different contaminants, such as mercury (Hg) and its methylated form, methylmercury (MeHg). However, few studies have assessed the impacts of Hg on bivalves under environmental conditions, and little is known on bivalve oxidative stress patterns due to Hg contamination. Therefore, this study aims to assess the Hg contamination in sediments as well as the concentration of Hg and MeHg in R. decussatus and R. philippinarum, and to identify the detoxification strategies of both species living in sympatry, in an aquatic system with historical Hg contamination. The risk to human health due to the consumption of clams was also evaluated. The results obtained demonstrated that total Hg concentration found in sediments from the most contaminated area was higher than the maximum levels established by Sediment Quality Guidelines. This study further revealed that the total Hg and MeHg accumulation in both species was strongly correlated with the total Hg contamination of the sediments. Nonetheless, the THg concentration in both species was lower than maximum permissible limits (MPLs) of THg defined by international organizations. R. decussatus and R. philippinarum showed an increase in lipid peroxidation levels along with the increase of THg accumulation by clams. Nevertheless, for both species, no clear trend was obtained regarding the activity of antioxidant (superoxide dismutase, catalase) and biotransformation (glutathione S-transferase) enzymes and metallothioneins with the increase of THg in clams. Overall, the present work demonstrated that both species can be used as sentinel species of contamination and that the consumption of these clams does not constitute a risk for human health.

  16. Lithography process for patterning HgI2 photonic devices

    DOEpatents

    Mescher, Mark J.; James, Ralph B.; Hermon, Haim

    2004-11-23

    A photolithographic process forms patterns on HgI.sub.2 surfaces and defines metal sublimation masks and electrodes to substantially improve device performance by increasing the realizable design space. Techniques for smoothing HgI.sub.2 surfaces and for producing trenches in HgI.sub.2 are provided. A sublimation process is described which produces etched-trench devices with enhanced electron-transport-only behavior.

  17. Oxidative stress in MeHg-induced neurotoxicity

    SciTech Connect

    Farina, Marcelo; Aschner, Michael; Rocha, Joao B.T.

    2011-11-15

    Methylmercury (MeHg) is an environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. Although the molecular mechanisms mediating MeHg-induced neurotoxicity are not completely understood, several lines of evidence indicate that oxidative stress represents a critical event related to the neurotoxic effects elicited by this toxicant. The objective of this review is to summarize and discuss data from experimental and epidemiological studies that have been important in clarifying the molecular events which mediate MeHg-induced oxidative damage and, consequently, toxicity. Although unanswered questions remain, the electrophilic properties of MeHg and its ability to oxidize thiols have been reported to play decisive roles to the oxidative consequences observed after MeHg exposure. However, a close examination of the relationship between low levels of MeHg necessary to induce oxidative stress and the high amounts of sulfhydryl-containing antioxidants in mammalian cells (e.g., glutathione) have led to the hypothesis that nucleophilic groups with extremely high affinities for MeHg (e.g., selenols) might represent primary targets in MeHg-induced oxidative stress. Indeed, the inhibition of antioxidant selenoproteins during MeHg poisoning in experimental animals has corroborated this hypothesis. The levels of different reactive species (superoxide anion, hydrogen peroxide and nitric oxide) have been reported to be increased in MeHg-exposed systems, and the mechanisms concerning these increments seem to involve a complex sequence of cascading molecular events, such as mitochondrial dysfunction, excitotoxicity, intracellular calcium dyshomeostasis and decreased antioxidant capacity. This review also discusses potential therapeutic strategies to counteract MeHg-induced toxicity and oxidative stress, emphasizing the use of organic selenocompounds, which generally present higher affinity for MeHg when compared to the classically

  18. Modeling Mercury Cadmium Telluride (HgCdTe) Photodiodes

    DTIC Science & Technology

    2009-11-01

    and Electron Devices Directorate, ARL and Dragica Vasileska Arizona State University, Tempe AZ 85287-5706...coefficient of Hg1–xCdxTe as a function of composition x (4). ......3 Figure 3. Comparison of the bandgap vs. lattice constant variation with alloy...proceeded deliberately and steadily for four decades in spite of the high vapor pressure of Hg at the melting point of HgCdTe and the known toxicity

  19. Modeling interactions of Hg(II) and bauxitic soils.

    PubMed

    Weerasooriya, Rohan; Tobschall, Heinz J; Bandara, Atula

    2007-11-01

    The adsorptive interactions of Hg(II) with gibbsite-rich soils (hereafter SOIL-g) were modeled by 1-pK surface complexation theory using charge distribution multi-site ion competition model (CD MUSIC) incorporating basic Stern layer model (BSM) to account for electrostatic effects. The model calibrations were performed for the experimental data of synthetic gibbsite-Hg(II) adsorption. When [NaNO(3)] > or = 0.01M, the Hg(II) adsorption density values, of gibbsite, Gamma(Hg(II)), showed a negligible variation with ionic strength. However, Gamma(Hg(II)) values show a marked variation with the [Cl(-)]. When [Cl(-)] > or = 0.01M, the Gamma(Hg(II)) values showed a significant reduction with the pH. The Hg(II) adsorption behavior in NaNO(3) was modeled assuming homogeneous solid surface. The introduction of high affinity sites, i.e., >Al(s)OH at a low concentration (typically about 0.045 sites nm(-2)) is required to model Hg(II) adsorption in NaCl. According to IR spectroscopic data, the bauxitic soil (SOIL-g) is characterized by gibbsite and bayerite. These mineral phases were not treated discretely in modeling of Hg(II) and soil interactions. The CD MUSIC/BSM model combination can be used to model Hg(II) adsorption on bauxitic soil. The role of organic matter seems to play a role on Hg(II) binding when pH>8. The Hg(II) adsorption in the presence of excess Cl(-) ions required the selection of high affinity sites in modeling.

  20. Liquidus temperatures of Hg-rich Hg-Cd-Te alloys

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Lehoczky, S. L.

    1983-01-01

    Measurements are made of the liquidus temperatures for ten (Hg/1-x/Cd)Te/1-y/ compositions in which x ranges from 0.091 to 0.401 and y ranges from 0.544 to 0.952. It is found that for metal-rich melts with the same x value, the liquidus temperature increases with y when y is in the range 0.5-0.7. This behavior is explained by the higher degree of association between Cd and Te than between Hg and Te in the melts. It is noted that recent calculated values of the liquidus isotherms by Tung et al. (1982) are in fair to good agreement with the experimental results obtained here.

  1. Transport properties of a 3D topological insulator based on a strained high-mobility HgTe film.

    PubMed

    Kozlov, D A; Kvon, Z D; Olshanetsky, E B; Mikhailov, N N; Dvoretsky, S A; Weiss, D

    2014-05-16

    We investigate the magnetotransport properties of strained 80 nm thick HgTe layers featuring a high mobility of μ ∼ 4 × 10(5) cm(2)/V · s. By means of a top gate, the Fermi energy is tuned from the valence band through the Dirac-type surface states into the conduction band. Magnetotransport measurements allow us to disentangle the different contributions of conduction band electrons, holes, and Dirac electrons to the conductivity. The results are in line with previous claims that strained HgTe is a topological insulator with a bulk gap of ≈ 15 meV and gapless surface states.

  2. Dual Hg-Rb magneto-optical trap.

    PubMed

    Witkowski, Marcin; Nagórny, Bartłomiej; Munoz-Rodriguez, Rodolfo; Ciuryło, Roman; Żuchowski, Piotr Szymon; Bilicki, Sławomir; Piotrowski, Marcin; Morzyński, Piotr; Zawada, Michał

    2017-02-20

    We present a two-species laser cooling apparatus capable of simultaneously collecting Rb and Hg atomic gases into a magneto-optical trap (MOT). The atomic sources, laser system, and vacuum set-up are described. While there is a loss of Rb atoms in the MOT due to photoionization by the Hg cooling laser, we show that it does not prevent simultaneous trapping of Rb and Hg. We also demonstrate interspecies collision-induced losses in the 87Rb-202Hg system.

  3. Experiments with a New 201Hg+ Ion Clock

    NASA Astrophysics Data System (ADS)

    Burt, E. A.; Taghavi-Larigani, S.; Lea, S. N.; Prestage, J. D.; Tjoelker, R. L.

    2009-04-01

    In this paper we describe a new clock based on 201Hg+. All previous mercury ion clocks have been based on 199Hg+. We have recently completed construction of the 201Hg+ clock and will describe modifications to the design of our existing 199Hg+ clocks to accommodate the new isotope. We will also describe initial spectroscopic measurements of the hyperfine manifold, and possible future experiments. One experiment could place a limit on variations in the strong interaction fundamental constant ratio mq/ΛQCD.

  4. HD 30963: a new HgMn star

    NASA Astrophysics Data System (ADS)

    Monier, R.; Gebran, M.; Royer, F.

    2016-12-01

    Using high dispersion high quality spectra of HD 30963 obtained with the echelle spectrograph SOPHIE at Observatoire de Haute Provence in November 2015, we show that this star, hitherto classified as a B9 III superficially normal star, is actually a new Chemically Peculiar star of the HgMn type. Spectrum synthesis reveals large overabundances of Mn, Sr, Y, Zr , Pt and Hg and pronounced underabundances of He and Ni which are characteristic of HgMn stars. We therefore propose that this interesting object be reclassified as a B9 HgMn star.

  5. Dual Hg-Rb magneto-optical trap

    NASA Astrophysics Data System (ADS)

    Witkowski, Marcin; Nagórny, Bartłomiej; Munoz-Rodriguez, Rodolfo; Ciuryło, Roman; Żuchowski, Piotr Szymon; Bilicki, Sławomir; Piotrowski, Marcin; Morzyński, Piotr; Zawada, Michał

    2017-02-01

    We present a two-species laser cooling apparatus capable of simultaneously collecting Rb and Hg atomic gases into a magneto-optical trap (MOT). The atomic sources, laser system, and vacuum set-up are described. While there is a loss of Rb atoms in the MOT due to photoionization by the Hg cooling laser, we show that it does not prevent simultaneous trapping of Rb and Hg. We also demonstrate interspecies collision-induced losses in the ${}^{87}$Rb-${}^{202}$Hg system.

  6. Shock-induced defects in HgO

    SciTech Connect

    Morosin, B.; Venturini, E.L.; Holman, G.T.; Newcomer, P.N.; Dunn, R.G.; Graham, R.A.

    1995-09-01

    Powder compacts of HgO have been subjected to shock-loading and preserved for postshock analysis to understand its reactivity and stability under transient temperature-pressure excursions. Recovered samples indicate several solid state reactions which are dependent on shock conditions. Metallic Hg is recovered in small amounts in the HgO compact as well as an as-yet unidentified ferromagnetic impurity not present in the as-received HgO powder. Further, there is evidence of reaction with the Cu capsule, forming an intermetallic alloy.

  7. Seasonal and Diurnal Variations of Hg(0) Over New England

    NASA Astrophysics Data System (ADS)

    Mao, H.; Talbot, R.; Sigler, J.; Sive, B.; Hegarty, J.

    2007-12-01

    Diurnal to interannual variability of Hg° over New England was investigated using multiple years of Hg° measurements at two inland sites, Thompson Farm (TF, 43.11° N, 70.95° W, 24 m, 25 km inland) and Pac Monadnock (PM, 42.86° N, 71.88° W, 700 m, 180 km inland), and one summer of measurements from a marine site, Appledore Island (AI, 42.97° N, 70.62° W, sea level), from the University of New Hampshire AIRMAP observing network. Possible sources were identified via a thorough examination of relationships between Hg° and a number of trace gases, e.g., CO, CO2, CH4, NOy, NO, SO2, and VOCs. The measurements of Hg at TF showed distinct seasonality with an annual maxima in late winter - early spring and a minima in early fall, with large day-to-day variation. A decreasing trend in the mixing ratio of Hg over the time period of March - September occurred at a rate of 0.5 - 0.6 ppqv d-1 for all years except 2004 (0.3 ppqv d-1). Measurements of Hg° at the elevated site PM exhibited much smaller daily and annual variation, particularly reflected in the slower warm season decline (relative to TF) of 0.2 and 0.3 ppqv d-1 in 2005 and 2006 respectively. The AI data appeared to track the variation observed at TF albeit with much higher minima. Hg° was correlated most strongly with CO and NOy in winter suggesting that anthropogenic emissions were the primary source of Hg° . Applying the Hg° - CO relationship, we found that the seasonally averaged Hg° mixing ratio of ~160 ppqv at PM can be considered the regional background level. The positive Hg° -NOy correlation along the lower boundary of all data points indicated dry deposition as a stronger sink for Hg° than suggested by previous studies. We estimated a dry deposition velocity for Hg° of 0.17 - 0.20 cm s-1, and a lifetime of ~11 days in the local PBL at TF. Correlation between Hg° and CHBr3 at both TF and AI suggested a role of the oceanic source influencing the ambient levels of Hg° in the marine and coastal

  8. Apollo 15 Index of 70 mm Photographs

    NASA Technical Reports Server (NTRS)

    1972-01-01

    All Apollo 15 70 mm photographs to which NASA photo numbers have been assigned are described in this index. In the first section all photographs are listed in sequence by NASA photo numbers. In subsequent sections, lunar surface and lunar orbital photographs are cross-indexed. Lunar surface photographs are listed in chronological order within the following categories: SEVA and LM window photos (LM window photos were taken before, between, and after EVA's), EVA 1, EVA 2, and EVA 3. Photographs of the lunar surface taken while in lunar orbit are cross-indexed by longitude in 10 deg increments, starting with the easternmost (farside) photos, and progressing to the westernmost (nearside) photos. Within each 10 deg interval of longitude, photographs are listed sequentially by NASA photo number, not by specific longitude of the principal point of each photograph.

  9. The Table Mountain 8-mm wavelength interferometer

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.; Gary, B. L.; Gulkis, S.; Olsen, E. T.; Soltis, F. S.; Yamane, N. I.

    1979-01-01

    A two-element radio interferometer operating at 8.33-mm wavelength has been developed at the Jet Propulsion Laboratory's Table Mountain Observatory near Wrightwood, CA. The interferometer employs a 5.5-m and a 3-m diameter antenna on an east-west baseline of 60 or 120 m, yielding fringe spacings at transit of 28 or 14 arcsec, respectively. The broad intermediate-frequency bandpass of 100-350 MHz and the system noise temperature of 500 K provide high sensitivity for the measurement of continuum sources. The interferometer has been used for high-resolution studies of the planets and the sun, and it is currently being adapted to study solar flare emissions at high spatial and time resolution.

  10. 40 CFR 80.618-80.619 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Violation Provisions §§ 80.618-80.619 Provisions for Foreign Refiners and Importers for...

  11. 40 CFR 80.514-80.519 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel General Information §§ 80.514-80.519 Motor Vehicle Diesel Fuel Standards and Requirements...

  12. 40 CFR 80.528-80.529 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Motor Vehicle Diesel Fuel Standards and Requirements §§ 80.528-80.529 Temporary...

  13. 40 CFR 80.514-80.519 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel General Information §§ 80.514-80.519 Motor Vehicle Diesel Fuel Standards and Requirements...

  14. 40 CFR 80.587-80.589 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Sampling and Testing §§ 80.587-80.589 Recordkeeping and Reporting Requirements...

  15. 40 CFR 80.541-80.549 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Geographic Phase-in Provisions §§ 80.541-80.549 Small Refiner Hardship Provisions...

  16. 40 CFR 80.528-80.529 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Motor Vehicle Diesel Fuel Standards and Requirements §§ 80.528-80.529 Temporary...

  17. 40 CFR 80.556-80.559 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Small Refiner Hardship Provisions §§ 80.556-80.559 Other Hardship Provisions...

  18. 40 CFR 80.537-80.539 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FUELS AND FUEL ADDITIVES Motor Vehicle Diesel Fuel; Nonroad, Locomotive, and Marine Diesel Fuel; and ECA Marine Fuel Temporary Compliance Option §§ 80.537-80.539 Geographic Phase-In Provisions...

  19. 40 CFR 60.4142 - Hg allowance allocations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Coal-Fired Electric Steam Generating Units Hg Allowance Allocations § 60.4142 Hg allowance allocations... from the unit's combustion of lignite, multiplied by 3.0; (B) Any portion of the unit's control period... boiler and has equipment used to produce electricity and useful thermal energy for industrial,...

  20. 40 CFR 60.4142 - Hg allowance allocations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Coal-Fired Electric Steam Generating Units Hg Allowance Allocations § 60.4142 Hg allowance allocations... from the unit's combustion of lignite, multiplied by 3.0; (B) Any portion of the unit's control period... boiler and has equipment used to produce electricity and useful thermal energy for industrial,...

  1. Hg localisation in Tillandsia usneoides L. (Bromeliaceae), an atmospheric biomonitor

    NASA Astrophysics Data System (ADS)

    Amado Filho, G. M.; Andrade, L. R.; Farina, M.; Malm, O.

    The Spanish moss, Tillandsia usneoides, has been applied as an atmospheric biomonitor of Hg contamination, although the mechanism of metal plant accumulation has not been understood until now. In the present work, analytical scanning electron microscopy (SEM) was used to localize Hg in T. usneoides exposed to a Hg-air-contaminated area during 15 days. After this period, Hg was determined by the flow injection mercury system, and plants were prepared for SEM observation and energy-dispersive X-ray analysis. A concentration of 2702±318 μg Hg g -1 was determined in exposed plants. The presented microanalytical results demonstrated that Hg was partly associated with atmospheric particles deposited upon the plant surface, but it was highly absorbed by the scales, stem and leaves surfaces and less absorbed by epidermal cells of T. usneoides. No Hg was detected in mesophyll parenchyma or in vascular system cells. The great surface adsorption area provided by the scales, in addition to the characteristics of T. usneoides morphology, especially of the node region, are suggested to confer the great capability of T. usneoides in Hg holding.

  2. Diel variations in photoinduced oxidation of Hg0 in freshwater.

    PubMed

    Garcia, Edenise; Poulain, Alexandre J; Amyot, Marc; Ariya, Parisa A

    2005-05-01

    Experiments have been conducted to determine diel variations in photoinduced Hg0 oxidation in lake water under natural Hg0(aq) concentrations. Pseudo-first-order rates of photooxidation (k') were calculated for water freshly collected in a Canadian Shield lake, Lake Croche (45 degrees 56' N, 74 degrees 00' W), at different periods of the day and subsequently incubated in the dark. Hg0 oxidation rates ranged from 0.02 to 0.07 h(-1), increasing from sunrise to noon and then decreasing throughout the remainder of the day. These changes paralleled those in sunlight intensity integrated over 1 h preceding water collection, and suggested that the water freshly collected in daylight was rich in photochemically produced Hg0 oxidants. It was also estimated that under intense solar radiation, even if oxidation rates reached a peak, reduction of Hg(II) was the prevalent redox process. Inversely, Hg0 oxidation overcame DGM production during the night or at periods of weaker light intensity. Overall, these findings explain the decreases in the DGM pool generally observed overnight. They also support previous reports that, during summer days, volatilization of Hg0 from water represent an important step in the Hg cycle in freshwater systems.

  3. Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands

    NASA Technical Reports Server (NTRS)

    Karpov, A.; Carter, M.; Lazareff, B.; Billon-Pierron, D.; Gundlach, K. H.

    1992-01-01

    We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K.

  4. Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands

    NASA Astrophysics Data System (ADS)

    Karpov, A.; Carter, M.; Lazareff, B.; Billon-Pierron, D.; Gundlach, K. H.

    We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K.

  5. Long-distance transport of Hg, Sb, and As from a mined area, conversion of Hg to methyl-Hg, and uptake of Hg by fish on the Tiber River basin, west-central Italy

    USGS Publications Warehouse

    Gray, John E.; Rimondi, Valentina; Costagliola, Pilario; Vaselli, Orlando; Lattanzi, Pierfranco

    2014-01-01

    Stream sediment, stream water, and fish were collected from a broad region to evaluate downstream transport and dispersion of mercury (Hg) from inactive mines in the Monte Amiata Hg District (MAMD), Tuscany, Italy. Stream sediment samples ranged in Hg concentration from 20 to 1,900 ng/g, and only 5 of the 17 collected samples exceeded the probable effect concentration for Hg of 1,060 ng/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in Tiber River sediment varied from 0.12 to 0.52 ng/g, and although there is no established guideline for sediment methyl-Hg, these concentrations exceeded methyl-Hg in a regional baseline site (<0.02 ng/g). Concentrations of Hg in stream water varied from 1.2 to 320 ng/L, all of which were below the 1,000 ng/L Italian drinking water Hg guideline and the 770 ng/L U.S. Environmental Protection Agency (USEPA) guideline recommended to protect against chronic effects to aquatic wildlife. Methyl-Hg concentrations in stream water varied from <0.02 to 0.53 ng/L and were generally elevated compared to the baseline site (<0.02 ng/L). All stream water samples contained concentrations of As (<1.0–6.2 μg/L) and Sb (<0.20–0.37 μg/L) below international drinking water guidelines to protect human health (10 μg/L for As and 20 μg/L for Sb) and for protection against chronic effects to aquatic wildlife (150 μg/L for As and 5.6 μg/L for Sb). Concentrations of Hg in freshwater fish muscle ranged from 0.052–0.56 μg/g (wet weight), mean of 0.17 μg/g, but only 17 % (9 of 54) exceeded the 0.30 μg/g (wet weight) USEPA fish muscle guideline recommended to protect human health. Concentrations of Hg in freshwater fish in this region generally decreased with increasing distance from the MAMD, where fish with the highest Hg concentrations were collected more proximal to the MAMD, whereas all fish collected most distal from Hg mines contained Hg below the 0.30 μg/g fish muscle

  6. Long-distance transport of Hg, Sb, and As from a mined area, conversion of Hg to methyl-Hg, and uptake of Hg by fish on the Tiber River basin, west-central Italy.

    PubMed

    Gray, John E; Rimondi, Valentina; Costagliola, Pilario; Vaselli, Orlando; Lattanzi, Pierfranco

    2014-02-01

    Stream sediment, stream water, and fish were collected from a broad region to evaluate downstream transport and dispersion of mercury (Hg) from inactive mines in the Monte Amiata Hg District (MAMD), Tuscany, Italy. Stream sediment samples ranged in Hg concentration from 20 to 1,900 ng/g, and only 5 of the 17 collected samples exceeded the probable effect concentration for Hg of 1,060 ng/g, above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in Tiber River sediment varied from 0.12 to 0.52 ng/g, and although there is no established guideline for sediment methyl-Hg, these concentrations exceeded methyl-Hg in a regional baseline site (<0.02 ng/g). Concentrations of Hg in stream water varied from 1.2 to 320 ng/L, all of which were below the 1,000 ng/L Italian drinking water Hg guideline and the 770 ng/L U.S. Environmental Protection Agency (USEPA) guideline recommended to protect against chronic effects to aquatic wildlife. Methyl-Hg concentrations in stream water varied from <0.02 to 0.53 ng/L and were generally elevated compared to the baseline site (<0.02 ng/L). All stream water samples contained concentrations of As (<1.0-6.2 μg/L) and Sb (<0.20-0.37 μg/L) below international drinking water guidelines to protect human health (10 μg/L for As and 20 μg/L for Sb) and for protection against chronic effects to aquatic wildlife (150 μg/L for As and 5.6 μg/L for Sb). Concentrations of Hg in freshwater fish muscle ranged from 0.052-0.56 μg/g (wet weight), mean of 0.17 μg/g, but only 17 % (9 of 54) exceeded the 0.30 μg/g (wet weight) USEPA fish muscle guideline recommended to protect human health. Concentrations of Hg in freshwater fish in this region generally decreased with increasing distance from the MAMD, where fish with the highest Hg concentrations were collected more proximal to the MAMD, whereas all fish collected most distal from Hg mines contained Hg below the 0.30

  7. Low-Friction Minilaparoscopy Outperforms Regular 5-mm and 3-mm Instruments for Precise Tasks

    PubMed Central

    Firme, Wood A.; Lima, Diego L.; de Paula Lopes, Vladmir Goldstein; Montandon, Isabelle D.; Filho, Flavio Santos; Shadduck, Phillip P.

    2015-01-01

    Background and Objectives: Therapeutic laparoscopy was incorporated into surgical practice more than 25 y ago. Several modifications have since been developed to further minimize surgical trauma and improve results. Minilaparoscopy, performed with 2- to 3-mm instruments was introduced in the mid 1990s but failed to attain mainstream use, mostly because of the limitations of the early devices. Buoyed by a renewed interest, new generations of mini instruments are being developed with improved functionality and durability. This study is an objective evaluation of a new set of mini instruments with a novel low-friction design. Method: Twenty-two medical students and 22 surgical residents served as study participants. Three designs of laparoscopic instruments were evaluated: conventional 5 mm, traditional 3 mm, and low-friction 3 mm. The instruments were evaluated with a standard surgical simulator, emulating 4 exercises of various complexities, testing grasping, precise 2-handed movements, and suturing. The metric measured was time to task completion, with 5 replicates for every combination of instrument–exercise–participant. Results: For all 4 tasks, the instrument design that performed the best was the same in both the medical student and surgical resident groups. For the gross-grasping task, the 5-mm conventional instruments performed best, followed by the low-friction mini instruments. For the 3 more complex and precise tasks, the low-friction mini instruments outperformed both of the other instrument designs. Conclusion: In standard surgical simulator exercises, low-friction minilaparoscopic instruments outperformed both conventional 3- and 5-mm laparoscopic instruments for precise tasks. PMID:26390530

  8. Discrete-line transitions from superdeformed to yrast states in {sup 194}Hg and {sup 192}Hg

    SciTech Connect

    Hackman, G.; Khoo, T.L.; Ackermann, D.

    1996-12-31

    Discrete-line {gamma}-ray decay from superdeformed (SD) to yrast states in {sup 194,192}Hg has been studied with the Gammasphere spectrometer. The previously established decay for the yrast SD band of {sup 194}Hg has been characterized further. In addition, one-step decays have been observed for {sup 194}Hg SD band 3, which fixes the excitation energy and spin of the last observed level of this band at E* = 7.455 MeV, J = 11{Dirac_h}. So far no direct decays from superdeformed to yrast states have been observed in {sup 192}Hg or in {sup 194}Hg band 2, a result which is consistent with fluctuations of the transition strengths.

  9. Isotonic similarities in isotope shifts from Hg to Ra.

    NASA Astrophysics Data System (ADS)

    Stroke, H. H.

    2003-04-01

    Isotope shifts (IS) in atomic spectra of heavy elements reflect largely the variation in of the nuclear charge distribution. Our early systematic measurements of IS for an extended range of stable and radioactive isotopes and nuclear isomers in Tl and Hg^1 showed that by displaying the relative IS, normalized to a chosen pair of isotopes, there was a striking similarity for the IS of isotones. This essentially divides out the electronic factor in the IS and allows the comparison of Δ for neighboring Z as N is varied. Following our further studies on Pb and Bi^2 and those on Fr at ISOLDE by the Orsay spectroscopy group^3, we found that the isotonic similarity extended to these elements. Since then, many additional measurements were made, principally at ISOLDE^4, extending to Ra the elements studied. The isotonic shift similarities persist from Z=80 to 88. We noted that the relative isotope and isomer shifts can be used to investigate the polarization of the nucleus by the added neutrons, a model used in a calculation by Barrett.^5 . The new data may serve further in this direction. ^1W,J.Tomlinson, H.H. Stroke, Nucl.Phys. 60, 614 (1964). ^2M. Barboza-Flores et al., Z.Phys. A 321, 85 (1985), ^3S. Liberman et al., Phys .Rev. A 22, 2732 (1980). ^4E,g. M.R. Pearson et al., J.Phys. G 26, 1829 (2000). ^5R.C. Barrett, Nucl. Phys. 88, 128 (1966).

  10. Tolerance and hyperaccumulation of a mixture of heavy metals (Cu, Pb, Hg, and Zn) by four aquatic macrophytes.

    PubMed

    Romero-Hernández, Jorge Alberto; Amaya-Chávez, Araceli; Balderas-Hernández, Patricia; Roa-Morales, Gabriela; González-Rivas, Nelly; Balderas-Plata, Miguel Ángel

    2017-03-04

    In the present investigation, four macrophytes, namely Typha latifolia (L.), Lemna minor (L.), Eichhornia crassipes (Mart.) Solms-Laubach, and Myriophyllum aquaticum (Vell.) Verdc, were evaluated for their heavy metal (Cu, Pb, Hg, and Zn) hyperaccumulation potential under laboratory conditions. Tolerance analyses were performed for 7 days of exposure at five different treatments of the metals mixture (Cu(+2), Hg(+2), Pb(+2), and Zn(+2)). The production of chlorophyll and carotenoids was determined at the end of each treatment. L. minor revealed to be sensitive, because it did not survive in all the tested concentrations after 72 hours of exposure. E. crassipes and M. aquaticum displayed the highest tolerance to the metals mixture. For the most tolerant species of aquatic macrophytes, The removal kinetics of E. crassipes and M. aquaticum was carried out, using the following mixture of metals: Cu (0.5 mg/L) and Hg, Pb, and Zn 0.25 mg/L. The obtained results revealed that E. crassipes can remove 99.80% of Cu, 97.88% of Pb, 99.53% of Hg, and 94.37% of Zn. M. aquaticum withdraws 95.2% of Cu, 94.28% of Pb, 99.19% of Hg, and 91.91% of Zn. The obtained results suggest that these two species of macrophytes could be used for the phytoremediation of this mixture of heavy metals from the polluted water bodies.

  11. Novel bioflocculant produced by salt-tolerant, alkaliphilic strain Oceanobacillus polygoni HG6 and its application in tannery wastewater treatment.

    PubMed

    Li, Jing; Yun, Yue-Qing; Xing, Li; Song, Lei

    2017-01-09

    The optimized production of MBF-HG6, which is a novel salt-tolerant alkaliphilic bioflocculant produced by Oceanobacillus polygoni with its application in tannery wastewater treatment was investigated in this study. It was found the optimal carbon source, nitrogen source, cation, and initial pH of the medium for bioflocculant production were starch, urea, Fe(2+), and pH 9.0, respectively. The best stability in the temperature range was from 0 to 80°C and the purified MBF-HG6 contained polysaccharides of 81.53% and proteins of 9.98%. The carboxyl, hydroxyl, and amino groups were determined in bioflocculants, while the optimized bioflocculating activity was observed as 90.25% for the dosages of 6.96mL MBF-HG6, 4.77mL CaCl2 (1%, m/v), and 19.24g/L NaCl using response surface methodology. In addition, SS and turbidity removal rates of the tannery wastewater (4g/L MBF-HG6) could, respectively, reach 46.49% and 91.08%, indicating that the great potential was emerged in enhancement of tannery wastewater treatment by MBF-HG6.

  12. Generation of Bessel Beams at mm- and Sub mm-wavelengths by Binary Optical Elements

    NASA Astrophysics Data System (ADS)

    Yu, Y. Z.; Dou, W. B.

    2008-07-01

    In this paper, binary optical elements (BOE’s) are designed for generating Bessel beams at mm- and sub mm- wavelengths. The design tool is to combine a genetic algorithm (GA) for global optimization with a two-dimension finite-difference time-domain (2-D FDTD) method for rigorous electromagnetic computation. The design process for converting a normally incident Gaussian beam into a Bessel beam is described in detail. Numerical results demonstrate that the designed BOE’s can not only successfully produce arbitrary order Bessel beams, but also have higher diffraction efficiencies when compared with amplitude holograms.

  13. Cold-electron bolometers for future mm and sub-mm sky surveys

    NASA Astrophysics Data System (ADS)

    Salatino, Maria; de Bernardis, Paolo; Mahashabde, Sumedh; Kuzmin, Leonid S.; Masi, Silvia

    2014-07-01

    Future sky surveys in the mm/sub-mm range, like the forthcoming balloon-borne missions LSPE, OLIMPO, SPIDER etc., will need detectors insensitive to cosmic rays (CRs) and with a NEP of the order of 10-17 ¥ 10-18 W/sqrt(Hz). The Cold-Electron Bolometers (CEBs) technology is promising, having the required proper- ties, since the absorber volume is extremely small and the electron system of the absorber is thermally insulated from the phonon system. We have developed an experimental setup to test the optical performance and the CRs insensitivity of CEBs, with the target of integrating them in the OLIMPO and LSPE focal planes.

  14. Size quantization in layered HgI/sub 2/ colloids

    SciTech Connect

    Peterson, M.W.; Micic, O.I.; Nozik, A.J.

    1988-07-14

    Colloidal particles of HgI/sub 2/ with a particle size less than about 25 /angstrom/ are formed by the reaction of HgCl/sub 2/ with NaI in acetonitrile. The particles are charged with Cl/sup -/ ions that fill normally empty tetrahedral coordination sites at the edges; therefore they have an empirical formula HgI/sub 2/Cl/sub 0.6//sup 0.6-/. About 40% of the mercury in the colloidal solution is in the form of the ionic complex HgI/sub 2/Cl/sup -/. These conclusions are based on extensive spectroscopic studies of various Hg-I-Cl species and experiments involving ultracentifugation, ultrafiltration, and treatment of the colloids with ion-exchange resins. The absorption spectrum of the colloidal HgI/sub 2/ consists of three peaks at 4.26, 4.94, and 6.04 eV, and is attributed to size quantization effects. This spectrum is consistent with the first three allowed transitions in a simple particle-in-a-box model with infinite potential barriers in which the colloidal particles have the usual tetrahedral, layered structure of red HgI/sub 2/, with dimensions of 26.1 /angstrom/ perpendicular to the layer plane (four layers thick) and 13.3 /angstrom/ in the direction parallel to the layer plane.

  15. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are required to obtain a title V permit. 63.1(b)(3) Record of the applicability determination No All affected... applicability of each paragraph of subpart A of this part to sources subject to subpart MM. 63.1(c)(2) Title...

  16. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are required to obtain a title V permit. 63.1(b)(3) Record of the applicability determination No All affected... applicability of each paragraph of subpart A of this part to sources subject to subpart MM. 63.1(c)(2) Title...

  17. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are required to obtain a title V permit. 63.1(b)(3) Record of the applicability determination No All affected... applicability of each paragraph of subpart A of this part to sources subject to subpart MM. 63.1(c)(2) Title...

  18. Influence of simultaneous doping of Sb and Pb on phase formation, superconducting and microstructural characteristics of HgBa 2Ca 2Cu 3O 8+ δ

    NASA Astrophysics Data System (ADS)

    Giri, Rajiv; Tiwari, R. S.; Srivastava, O. N.

    2007-01-01

    We report systematic studies of structural, microstructural and transport properties of (Hg 0.80Sb 0.2- xPb x)Ba 2Ca 2Cu 3O 8+ δ (where x = 0.0, 0.05, 0.1, 0.15, 0.2) compounds. Bulk polycrystalline samples have been prepared by two-step solid-state reaction route at ambient pressure. It has been observed that simultaneous substitution of Sb and Pb at Hg site in oxygen deficient HgO δ layer of HgBa 2Ca 2Cu 3O 8+ δ cuprate high- Tc superconductor leads to the formation of Hg-1223 as the dominant phase. Microstructural investigations of the as grown samples employing scanning electron microscopy reveal single crystal like large grains embodying spiral like features. Superconducting properties particularly transport current density ( Jct) have been found to be sensitive to these microstructural features. As for example (Hg 0.80Sb 0.05Pb 0.15)Ba 2Ca 2Cu 3O 8+ δ compound which exhibits single crystal like large grains (∼50 μm) and appears to result through spiral growth mechanism, shows highest Jct (∼1.85 × 10 3 A/cm 2) at 77 K. A possible mechanism for the generation of spiral like features and correlation between microstructural features and superconducting properties have been put forward.

  19. Growth of HgZnTe Layers by LPE Technique

    DTIC Science & Technology

    1988-03-01

    Solid solution mixtures of a wide band gap II-VI compound with one constituent being the semimetal HgTe may be tuned to yield narrow gap...experimental research into the narrow band gap range of this solid solution . In the present work the LPE of Hg1-xZnxTe was studied, focusing on the...evaluation of this technique as a tool for achieving epitaxial layers of the ’new material’, the solid solution Hg1-xZnxTe, with morphological, crystalline

  20. Improved fabrication of HgI/sub 2/ nuclear radiation detectors by machine-cleaving

    SciTech Connect

    Levi, A.; Burger, A.; Schieber, M.; Vandenberg, L.; Yellon, W.B.; Alkire, R.W.

    1982-01-01

    The perfection of machine-cleaved sections from HgI/sub 2/ bulk crystals was examined. The perfection of the machine-cleaved sections as established by gamma diffraction rocking curves was found to be much better than the perfection of hand-cleaved sections or as grown thin platelets, reaching a perfection similar to that of the wire-sawn sections of HgI/sub 2/. A correlation between the perfection and the thickness of the machine-cleaved section was also found, i.e., the thicker the cleaved-section the more perfect it is. The reproducibility of the fabrication was significantly improved by using machine cleaving in the process of fabrication. Large single crystals of HgI/sub 2/ weighing 20 to 200 g, can be grown from the vapor phase using the TOM Technique. In order to fabricate nuclear radiation detectors from these single crystals, thin sections of about 0.4 to 0.8 mm thickness have to be prepared. Up till now, the state-of-the-art of fabricating HgI/sub 2/ nuclear radiation detectors involved two methods to get thin sections from the large single crystals: (1) hand-cleaving using a razor-blade and (2) solution wire sawing. The chemical wire sawing method involves a loss of about 50% of the crystal volume and is usually followed by a chemical polishing process which involves a significant loss of volume of the original volume. This procedure is complicated and wasteful. The traditional fabrication method, i.e., hand-cleaving followed by rapid nonselective chemical etching, is simpler and less wasteful.

  1. Results Of Hg Speciation Testing On DWPF SMECT-1, SMECT-3, And SMECT-5 Samples

    SciTech Connect

    Bannochie, C.

    2016-01-07

    The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The thirteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) from Sludge Receipt and Adjustment Tank (SRAT) Batch 736 and 738 samples. Triplicate samples of each material were prepared for this shipment. Each replicate was analyzed for seven Hg species: total Hg, total soluble (dissolved) Hg, elemental Hg [Hg(0)], ionic (inorganic) Hg [Hg(I) and Hg(II)], methyl Hg [CH3Hg-X, where X is a counter anion], ethyl Hg [CH3CH2-Hg-X, where X is a counter anion], and dimethyl Hg [(CH3)2Hg]. The difference between the total Hg and total soluble Hg measurements gives the particulate Hg concentration, i.e. Hg adsorbed to the surface of particulate matter in the sample but without resolution of the specific adsorbed species. The average concentrations of Hg species in the aqueous samples derived from Eurofins reported data corrected for dilutions performed by SRNL are tabulated.

  2. Magnetotransport in double quantum well with inverted energy spectrum: HgTe/CdHgTe

    NASA Astrophysics Data System (ADS)

    Yakunin, M. V.; Suslov, A. V.; Popov, M. R.; Novik, E. G.; Dvoretsky, S. A.; Mikhailov, N. N.

    2016-02-01

    We present an experimental study of the double-quantum-well (DQW) system made of two-dimensional layers with inverted energy band spectrum: HgTe. The magnetotransport reveals a considerably larger overlap of the conduction and valence subbands than in known HgTe single quantum wells (QW), which may be regulated here by an applied gate voltage Vg. This large overlap manifests itself in a much higher critical field Bc separating the range above it with a plain behavior of the Hall magnetoresistance ρx y(B ) , where the quantum peculiarities shift linearly with Vg, and the range below with a complicated behavior. In the latter case, specific structures in ρx y(B ) are formed like a double-N -shaped ρx y(B ) , reentrant sign-alternating quantum Hall effect with transitions into a zero-filling-factor state, etc., which are clearly manifested here due to better magnetic quantization at high fields, as compared to the features seen earlier in a single HgTe QW. The coexisting electrons and holes were found in the whole investigated range of positive and negative Vg as revealed (i) from fits to the low-field N -shaped ρx y(B ) , (ii) from the Fourier analysis of oscillations in ρx x(B ) , and (iii) from a specific behavior of ρx y(B ) at high positive Vg. A peculiar feature here is that the found electron density n remains almost constant in the whole range of investigated Vg while the hole density p drops down from the value a factor of 6 larger than n at extreme negative Vg to almost zero at extreme positive Vg passing through the charge-neutrality point. We show that this difference between n and p stems from an order of magnitude larger density of states for holes in the lateral valence subband maxima than for electrons in the conduction subband minimum. We analyze our observations on the basis of a calculated picture of magnetic levels in a DQW and suggest that their specificity is due to (i) a nonmonotonic course of the valence subband magnetic levels and an

  3. Competition among thiols and inorganic sulfides and polysulfides for Hg and MeHg in wetland soils and sediments under suboxic conditions: Illumination of controversies and implications for MeHg net production

    NASA Astrophysics Data System (ADS)

    Skyllberg, Ulf

    2008-12-01

    Current research focus in mercury biogeochemistry is on the net production and accumulation of methyl mercury (MeHg) in organisms. The activity of iron- and sulfate-reducing bacteria (FeRB and SRB) has been identified as important for MeHg production. There are indications of a passive uptake of neutral Hg-sulfides by SRB, as well as of a facilitated bacterial uptake of Hg complexed by small organic molecules. In order to understand these processes, the chemical speciation of Hg and MeHg, and most important, the competition among organic thiols and inorganic sulfides and polysulfides, needs to be clarified under suboxic conditions (nM to low μM range of total sulfide concentrations) in wetland soils and sediments. In this paper the chemical speciation of Hg and MeHg is modeled at pH 4.0 and 7.0 in a conceptual wetland soil/sediment with typical concentrations of thiols, sulfides, Hg, and MeHg. Effects of precipitated HgS(s), the formation of Hg-polysulfides, and the size of the controversial stability constant for the formation of HOHgSH0 (aq) are emphasized. The outcome of the modeling is discussed in light of chosen stability constants for Hg complexes with thiols, sulfides, and polysulfides. It is concluded that organic thiols are competitive with inorganic sulfides in the approximate total sulfide concentration range 0-1 μm. It is also concluded that increases in absolute aqueous concentrations of MeHg, or the molar ratio of dissolved MeHg/Hg, are not appropriate as indirect measures of MeHg net production, unless changes and differences in solubility of MeHg and Hg are corrected for.

  4. Using X-ray microscopy and Hg L3 XANES to study Hg binding in the rhizosphere of Spartina cordgrass.

    PubMed

    Patty, Cynthia; Barnett, Brandy; Mooney, Bridget; Kahn, Amanda; Levy, Silvio; Liu, Yijin; Pianetta, Piero; Andrews, Joy C

    2009-10-01

    San Francisco Bay has been contaminated historically by mercury from mine tailings as well as contemporary industrial sources. Native Spartina foliosa and non-native S. alterniflora-hybrid cordgrasses are dominant florae within the SF Bay estuary environment. Understanding mercury uptake and transformations in these plants will help to characterize the significance of their roles in mercury biogeochemical cycling in the estuarine environment. Methylated mercury can be biomagnified up the food web, resulting in levels in sport fish up to 1 million times greater than in surrounding waters and resulting in advisories to limit fish intake. Understanding the uptake and methylation of mercury in the plant rhizosphere can yield insight into ways to manage mercury contamination. The transmission X-ray microscope on beamline 6-2 at the Stanford Synchrotron Radiation Lightsource (SSRL) was used to obtain absorption contrast images and 3D tomography of Spartina foliosa roots that were exposed to 1 ppm Hg (as HgCl2) hydroponically for 1 week. Absorption contrast images of micrometer-sized roots from S. foliosa revealed dark particles, and dark channels within the root, due to Hg absorption. 3D tomography showed that the particles are on the root surface, and slices from the tomographic reconstruction revealed that the particles are hollow, consistent with microorganisms with a thin layer of Hg on the surface. Hg L3 XANES of ground-up plant roots and Hg L3 micro-XANES from microprobe analysis of micrometer-sized roots (60-120 microm in size) revealed three main types of speciation in both Spartina species: Hg-S ligation in a form similar to Hg(II) cysteine, Hg-S bonding as in cinnabar and metacinnabar, and methylmercury-carboxyl bonding in a form similar to methylmercury acetate. These results are interpreted within the context of obtaining a "snapshot" of mercury methylation in progress.

  5. Using X-ray Microscopy and Hg L3 XANES to study Hg Binding in the Rhizosphere of Spartina Cordgrass

    PubMed Central

    Patty, Cynthia; Barnett, Brandy; Mooney, Bridget; Kahn, Amanda; Levy, Silvio; Liu, Yijin; Pianetta, Piero; Andrews, Joy C

    2009-01-01

    San Francisco Bay has been contaminated historically by mercury from mine tailings as well as contemporary industrial sources. Native Spartina foliosa and non-native S. alterniflora-hybrid cordgrasses are dominant florae within the SF Bay estuary environment. Understanding mercury uptake and transformations in these plants will help to characterize the significance of their roles in mercury biogeochemical cycling in the estuarine environment. Methylated mercury can be biomagnified up the food web, resulting in levels in sport fish up to one million times greater than in surrounding waters and resulting in advisories to limit fish intake. Understanding the uptake and methylation of mercury in the plant rhizosphere can yield insight into ways to manage mercury contamination. The transmission x-ray microscope on beamline 6-2 at the Stanford Synchrotron Radiation Lightsource (SSRL) was used to obtain absorption contrast images and 3D tomography of Spartina foliosa roots that were exposed to 1 ppm Hg (as HgCl2) hydroponically for one week. Absorption contrast images of micron-sized roots from S. foliosa revealed dark particles, and dark channels within the root, due to Hg absorption. 3D tomography showed that the particles are on the root surface, and slices from the tomographic reconstruction revealed that the particles are hollow, consistent with microorganisms with a thin layer of Hg on the surface. Hg L3 XANES of ground-up plant roots and Hg L3 micro-XANES from microprobe analysis of micron-sized roots (60–120 microns in size) revealed three main types of speciation in both Spartina species: Hg-S ligation in a form similar to Hg(II) cysteine, Hg-S bonding as in cinnabar and metacinnabar, and methylmercury-carboxyl bonding in a form similar to methylmercury acetate. These results are interpreted within the context of obtaining a “snapshot” of mercury methylation in progress. PMID:19848152

  6. A New Trapped Ion Clock Based on Hg-201(+)

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, S.; Burt, E. A.; Lea, S. N.; Prestage, J. D.; Tjoelker, R. L.

    2009-01-01

    There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave clock: Hg-199(+) and Hg-201(+). Virtually all trapped mercury ion clocks to date have used the 199 isotope. We have begun to investigate the viability of a trapped ion clock based on Hg-201(+). We have measured the unperturbed frequency of the (S-2)(sub 1/2) F = 1, m(sub F) = 0 to (S-2)(sub 1/2) F = 2, m(sub F) = 0 clock transition to be 29.9543658211(2) GHz. In this paper we describe initial measurements with Hg-201(+) and new applications to clocks and fundamental physics.

  7. Photogalvanic Effects in HgTe Quantum Wells

    NASA Astrophysics Data System (ADS)

    Wittmann, B.; Danilov, S. N.; Kwon, Z. D.; Mikhailov, N. N.; Dvoretsky, S. A.; Ravash, R.; Prettl, W.; Ganichev, S. D.

    We report on the observation of the terahertz radiation induced circular (CPGE) and linear (LPGE) photogalvanic effects in HgTe quantum wells. The current response is well described by the phenomenological theory of CPGE and LPGE.

  8. MBE Growth, Characterization and Electronic Device Processing of HgCdTe, HgZnTe, Related Heterojunctions and HgCdTe-CdTe Superlattices

    DTIC Science & Technology

    1987-12-31

    and 3. T. NI. Wotherspoon. J. Phys. D 12, LI 117 (1979). ( 100) orientation, whereas p-type Hg, - Cd.Te layers are T~ P. Faune . J1. Reno, S...parameters are well con- ’J. P. Faune and A. Million. ]. Cryst. Growth 54. 582 (198 1) trolled, the quality of Hg1 - Cd.Te grown in both the ’J. P... Faune and A. Million. AppI. Phys. Lett- 41, 264 (1982). ( Ill ) B and the ( 100) orientations is comparable, thus giv- J P. Faurie. S. Sivananthan. NI

  9. MASTER: a radiometer for mm and sub-mm observations from the Antarctic Plateau

    NASA Astrophysics Data System (ADS)

    Boella, G.; Gervasi, M.; Passerini, A.; Sironi, G.; Tartari, A.; Zannoni, M.; Natale, V.

    A radiometer based on SIS mixers for astrophysical observations is being assembled. The system, cooled to cryogenic temperature by a pulse tube refrigerator, is intended for operation on the Antartic Plateau during the local winter, using the mm dishes available there in the future. The system prototype will be tested at the focus of the 2.6m MITO telescope at the Testa Grigia Observatory on the italian Alps. We discuss the system characteristics and the observational programs.

  10. Lifetime Measurement of HgCdTe Semiconductor Material

    DTIC Science & Technology

    2012-03-01

    measurement of minority carrier lifetime using the photoconductive decay method. This experiment was conducted to analyze the minority carrier lifetime of...lifetime, photoconductive decay. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 18 19a. NAME OF...the photoconductive decay method was used. To measure the lifetime of the HgCdTe samples using the photoconductive decay method, samples of HgCdTe

  11. HgI sub 2 low energy beta particle detector

    SciTech Connect

    Shah, K.S.; Squillante, M.R.; Entine, G. )

    1990-04-01

    This paper reports on a HgI{sub 2} device structure designed and tested which allows HgI{sub 2} to be used to make low energy beta particle detectors. The devices detected tritium beta particles with about a 25% efficiency. In addition, an encapsulation scheme was identified which has the potential to protect the devices while permitting most of the beta particles to reach the active region.

  12. Transient and diffusion analysis of HgCdTe

    NASA Technical Reports Server (NTRS)

    Clayton, J. C.

    1982-01-01

    Solute redistribution during directional solidification of HgCdTe is addressed. Both one-dimensional and two-dimensional models for solute redistribution are treated and model results compared to experiment. The central problem studied is the cause of radial inhomogeneities found in directionally solidified HgCdTe. A large scale gravity-driven interface instability, termed shape instability, is postulated to be the cause of radial inhomogeneities. Recommendations for future work, along with appropriate computer programs, are included.

  13. System performance advances of 18-mm and 16-mm subminiature image intensifier sensors

    NASA Astrophysics Data System (ADS)

    Thomas, Nils I.

    2000-11-01

    Night vision system design has been centered aroudn the An/AVS-6 and AN/PVS-7 night vision goggle systems for the past 20 years. Goggle performance has improved during this time through increased performance of the image intensifier sensor, primarily the Omni IV sensor from ITT Industries Night Vision. Most of this improvement has been at the optimal light level (1E-3 fc scene illumination). Recent advances in image sensor performance from the filmless Generation (Gen) IV sensors has increased the low light level performance of night vision devices from 0.3 cy/mr to 0.7 cy/mr. In addition, sensor packaging design requirements have forced night vision sensor manufactures to design light weight, small volume sensors. ITT recently has designed such a sensor in a 16-mm format. This sensor if 50% lighter, up to 50% shorter, and has design features that simplify the objective lens design. New night vision goggles have been, and are being, designed which reduce the perceived head-supported weight. This paper presents signal-to-noise ratio, halo, and other film-less sensor data and similar 16-mm subminiature sensor data. The resulting system performance data will be described. Finally, the system design improvements and relationships with the subminiature 16-mm subminiature sensor will be given.

  14. Direct detection of the mercury-nitrogen bond in the thymine-Hg(II)-thymine base-pair with (199)Hg NMR spectroscopy.

    PubMed

    Dairaku, Takenori; Furuita, Kyoko; Sato, Hajime; Šebera, Jakub; Yamanaka, Daichi; Otaki, Hiroyuki; Kikkawa, Shoko; Kondo, Yoshinori; Katahira, Ritsuko; Matthias Bickelhaupt, F; Fonseca Guerra, Célia; Ono, Akira; Sychrovský, Vladimír; Kojima, Chojiro; Tanaka, Yoshiyuki

    2015-05-18

    We have observed the 1-bond (199)Hg-(15)N J-coupling ((1)J((199)Hg,(15)N) = 1050 Hz) within the Hg(II)-mediated thymine-thymine base pair (T-Hg(II)-T). This strikingly large (1)J((199)Hg,(15)N) is the first one for canonical sp(2)-nitrogen atoms, which can be a sensitive structure-probe of N-mercurated compounds and a direct evidence for N-mercuration.

  15. A new trapped ion atomic clock based on 201Hg+.

    PubMed

    Burt, Eric A; Taghavi-Larigani, Shervin; Tjoelker, Robert L

    2010-03-01

    High-resolution spectroscopy has been performed on the ground-state hyperfine transitions in trapped (201)Hg+ ions as part of a program to investigate the viability of (201)Hg+ for clock applications. Part of the spectroscopy work was directed at magnetic-field-sensitive hyperfine lines with delta m(F) = 0, which allow accurate Doppler-free measurement of the magnetic field experienced by the trapped ions. Although it is possible to measure Doppler-free magnetic-field-sensitive transitions in the commonly used clock isotope, (199)Hg+, it is more difficult. In this paper, we discuss how this (199)Hg+ feature may be exploited to produce a more stable clock or one requiring less magnetic shielding in environments with magnetic field fluctuations far in excess of what is normally found in the laboratory. We have also determined that in discharge-lamp-based trapped mercury ion clocks, the optical pumping time for (201)Hg+ is about 3 times shorter than that of (199)Hg+ This can be used to reduce dead time in the interrogation cycle for these types of clocks, thereby reducing the impact of local oscillator noise aliasing effects.

  16. Crystal structure of K[Hg(SCN)3] - a redetermination.

    PubMed

    Weil, Matthias; Häusler, Thomas

    2014-09-01

    The crystal structure of the room-temperature modification of K[Hg(SCN)3], potassium tri-thio-cyanato-mercurate(II), was redetermined based on modern CCD data. In comparison with the previous report [Zhdanov & Sanadze (1952 ▶). Zh. Fiz. Khim. 26, 469-478], reliability factors, standard deviations of lattice parameters and atomic coordinates, as well as anisotropic displacement parameters, were revealed for all atoms. The higher precision and accuracy of the model is, for example, reflected by the Hg-S bond lengths of 2.3954 (11), 2.4481 (8) and 2.7653 (6) Å in comparison with values of 2.24, 2.43 and 2.77 Å. All atoms in the crystal structure are located on mirror planes. The Hg(2+) cation is surrounded by four S atoms in a seesaw shape [S-Hg-S angles range from 94.65 (2) to 154.06 (3)°]. The HgS4 polyhedra share a common S atom, building up chains extending parallel to [010]. All S atoms of the resulting (1) ∞[HgS2/1S2/2] chains are also part of SCN(-) anions that link these chains with the K(+) cations into a three-dimensional network. The K-N bond lengths of the distorted KN7 polyhedra lie between 2.926 (2) and 3.051 (3) Å.

  17. Fura-2 measurement of cytosolic calcium in HgCl/sub 2/-treated rabbit renal turbular cells

    SciTech Connect

    Trump, B.F.; Smith, M.W.

    1986-05-01

    This abstract reports the effect of HgCl/sub 2/ on cytosolic ionized calcium (Ca/sup 2 +/)/sub c/, measured by the fluorescent chelator Fura-2, in trypsinized rabbit renal tubular cells at 37/sup 0/C in Hanks salt solution, pH 7.2, containing 1.37 mM CaCl/sub 2/. Viability measured fluorometrically with propidium iodide correlated well with that determined using trypan blue. HgCl/sub 2/ (1-10 ..mu..M) induced rapid and dose-dependent increases up to 5-fold normal (Ca/sup 2 +/)/sub c/. After 1-3 min the rate of increase slowed or stopped. At higher doses of HgCl/sub 2/ (20-100 ..mu..M) an unexpected pattern of (Ca/sup 2 +/)/sub c/ changes occurred. After an initial 5-6-fold increase by 1 min, (Ca/sup 2 +/)/sub c/ decreased in the next 2-3 min to 2-3-fold normal levels. This change was followed by a second increase of (Ca/sup 2 +/)/sub c/ at a much slower rate which did appear to be dose-related. Calcium channel blockers and calmodulin inhibitors had little or no effect. Inhibitors of mitochondrial function, antimycin and 2,4-dinitrophenol, interfered with the fluorescent assay; KCN totally inhibited HgCl/sub 2/-induced (Ca/sup 2 +/)/sub c/ changes while hypoxia had no apparent effect. The -SH group binding compound N-ethyl maleimide increased (Ca/sup 2 +/)/sub c/ 4-5 fold; addition of 25 ..mu..M Hg caused faster peaking and recovery of (Ca/sup 2 +/)/sub c/. The mechanism of Ca/sup 2 +/ buffering triggered by higher HgCl/sub 2/ concentrations is as yet unknown.

  18. Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l)

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The optical absorption spectra of the vapor phase over HgI2(s,l) were measured for wavelengths between 200 and 600 nm. The spectra show that the sample sublimed congruently into HgI2 with no Hg or I2 absorption spectrum observed. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were determined. From these constants the vapor pressure of H912, P, was established as a function of temperatures for the liquid and the solid Beta-phases. The expressions correspond to the enthalpies of vaporization and sublimation of 15.30 and 20.17 Kcal/mole, respectively, for the liquid and the Beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 Kcal/mole and the intersection of the two expressions gives a melting point of 537 K.

  19. Mid-term evaluation of Sorin Soprano bioprostheses in patients with a small aortic annulus mm.

    PubMed

    Vohra, Hunaid A; Whistance, Robert N; Bolgeri, Marco; Velissaris, Theodore; Tsang, Geoffrey M K; Barlow, Clifford W; Ohri, Sunil K

    2010-03-01

    We set to examine the mid-term outcome after aortic valve replacement (AVR) with Soprano pericardial stented bioprosthesis measuring mm. Sixty-eight patients underwent AVR between June 2003 and January 2006 (50 women; median age 77 years; range 60-89 years). Preoperatively, 60 patients (88.2%) were in New York Heart Association (NYHA) class III/IV. The mean EuroSCORE was 6.7+/-2.3. Supra-annular aortoplasty was performed in 21 patients (30.9%), out of which 11 patients received an 18 mm prosthesis (55%). The median follow-up was 45.5 months (0.1-62 months). The 30-day mortality was 4.4% (n=3) with no early valve-related deaths. No patient suffered a cerebrovascular accident and no patient required replacement of prosthesis for coronary malperfusion. Postoperatively, the mean gradient across the 18 mm bioprosthesis (n=20) was 25+/-8.9 mmHg and across the 20 mm bioprosthesis (n=48) was 25.5+/-7.3 mmHg (P=NS). During follow-up, there was no valve-related death, re-operation for structural valve degeneration, endocarditis or valve thrombosis. There were five late deaths and actuarial survival at three and five years was 92.7+/-3.1% and 81.0+/-6.9%, respectively. At last follow-up, 86.7% (n=52) of survivors were in NYHA class I/II. AVR with Soprano bioprosthesis measuring mm is associated with excellent mid-term outcome. Continued follow-up is required to determine the long-term efficacy of the prosthesis.

  20. [Influence of inorganic ions and humic acid on the removal of Pb(II) and Hg(II) in water by zero-valent iron].

    PubMed

    Shi, Qiu-Ling; Zhou, Xin; Zhang, Jin-Zhong; Qiu, Xin-Kai

    2014-08-01

    The effects of Ca2+, Cl- and humic acid (HA) on the removal rates of Pb(II) and Hg(II) in water by zero-valent (ZVI) and the kinetic characteristics were studied, and the removal mechanism of Pb(II) and Hg(II) by ZVI were preliminarily investigated using X-ray diffraction (XRD). The results indicated that the removal mechanism of Pb(II) might mainly be attributed to the adsorption and co-precipitation of ZVI, while that of Hg(II) might mainly be attributed to the oxidation-reduction of ZVI. With the increase of Ca2+ concentration, the removal rates of Hg(II) and Pb(II) showed the trends of gradual increase and slight decrease, respectively. The Hg(II) removal increased with increasing Cl- concentration, whereas no obvious increase in Pb(II) removal was observed. The removal rates of Hg(II) and Pb(II) showed the trends of slow increase and slow decrease with increasing HA concentration, respectively. When Ca2+, Cl- and HA coexisted, the removal rates of Hg(II) and Pb(II) reached 99.71% and 97.95%, respectively. The removal processes of Pb(II) and Hg(II) could be described by pseudo first-order reaction kinetic equations when Ca2+, Cl- and HA existed alone and in combination. The removal rate constant of Pb(II) was the maxinum (0.024 0 min(-1)) when 5 mg x L(-1) HA existed alone, whereas that of Hg(II) was the maximum (0.0169 min(-1)) when 0.80 mmol x L(-1) Ca2+ existed alone.

  1. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  2. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  3. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  4. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  5. A universal sensor for mercury (Hg, Hg(I), Hg(II)) based on silver nanoparticle-embedded polymer thin film.

    PubMed

    Ramesh, G V; Radhakrishnan, T P

    2011-04-01

    Detection of mercury at concentration levels down to parts-per-billion is a problem of fundamental and practical interest due to the high toxicity of the metal and its role in environmental pollution. The extensive research in this area has been focused primarily on specific sensing of mercuric (Hg(2+)) ion. As mercury exists in the oxidation states, +2, +1 and 0 all of which are highly toxic, a universal sensor covering all the three while ensuring high sensitivity, selectivity, and linearity of response, and facilitating in situ as well as ex situ deployment, would be very valuable. Silver nanoparticle-embedded poly(vinyl alcohol) (Ag-PVA) thin film fabricated through a facile protocol is shown to be a fast, efficient and selective sensor for Hg(2+), Hg(2)(2+) and Hg in aqueous medium with a detection limit of 1 ppb. The sensor response is linear in the 10 ppb to 1 ppm concentration regime. A unique characteristic of the thin film based sensor is the blue shift occurring concomitantly with the decrease in the surface plasmon resonance absorption upon interaction with mercury, making the sensing highly selective. Unlike the majority of known sensors that work only in situ, the thin film sensor can be used ex situ as well. Examination of the thin film using microscopy and spectroscopy through the sensing process provides detailed insight into the sensing event.

  6. Two-dimensional topological insulators with tunable band gaps: Single-layer HgTe and HgSe

    DOE PAGES

    Li, Jin; He, Chaoyu; Meng, Lijun; ...

    2015-09-14

    Here, we report that two-dimensional (2D) topological insulators (TIs) with large band gaps are of great importance for the future applications of quantum spin Hall (QSH) effect. Employing ab initio electronic calculations we propose a novel type of 2D topological insulators, the monolayer (ML) low-buckled (LB) mercury telluride (HgTe) and mercury selenide (HgSe), with tunable band gap. We demonstrate that LB HgTe (HgSe) monolayers undergo a trivial insulator to topological insulator transition under in-plane tensile strain of 2.6% (3.1%) due to the combination of the strain and the spin orbital coupling (SOC) effects. Furthermore, the band gaps can be tunedmore » up to large values (0.2 eV for HgTe and 0.05 eV for HgSe) by tensile strain, which far exceed those of current experimentally realized 2D quantum spin Hall insulators. Our results suggest a new type of material suitable for practical applications of 2D TI at room-temperature.« less

  7. Two-dimensional topological insulators with tunable band gaps: Single-layer HgTe and HgSe

    SciTech Connect

    Li, Jin; He, Chaoyu; Meng, Lijun; Xiao, Huaping; Tang, Chao; Wei, Xiaolin; Kim, Jinwoong; Kioussis, Nicholas; Stocks, G. Malcolm; Zhong, Jianxin

    2015-09-14

    Here, we report that two-dimensional (2D) topological insulators (TIs) with large band gaps are of great importance for the future applications of quantum spin Hall (QSH) effect. Employing ab initio electronic calculations we propose a novel type of 2D topological insulators, the monolayer (ML) low-buckled (LB) mercury telluride (HgTe) and mercury selenide (HgSe), with tunable band gap. We demonstrate that LB HgTe (HgSe) monolayers undergo a trivial insulator to topological insulator transition under in-plane tensile strain of 2.6% (3.1%) due to the combination of the strain and the spin orbital coupling (SOC) effects. Furthermore, the band gaps can be tuned up to large values (0.2 eV for HgTe and 0.05 eV for HgSe) by tensile strain, which far exceed those of current experimentally realized 2D quantum spin Hall insulators. Our results suggest a new type of material suitable for practical applications of 2D TI at room-temperature.

  8. Two-dimensional topological insulators with tunable band gaps: Single-layer HgTe and HgSe

    PubMed Central

    Li, Jin; He, Chaoyu; Meng, Lijun; Xiao, Huaping; Tang, Chao; Wei, Xiaolin; Kim, Jinwoong; Kioussis, Nicholas; Malcolm Stocks, G.; Zhong, Jianxin

    2015-01-01

    Two-dimensional (2D) topological insulators (TIs) with large band gaps are of great importance for the future applications of quantum spin Hall (QSH) effect. Employing ab initio electronic calculations we propose a novel type of 2D topological insulators, the monolayer (ML) low-buckled (LB) mercury telluride (HgTe) and mercury selenide (HgSe), with tunable band gap. We demonstrate that LB HgTe (HgSe) monolayers undergo a trivial insulator to topological insulator transition under in-plane tensile strain of 2.6% (3.1%) due to the combination of the strain and the spin orbital coupling (SOC) effects. Furthermore, the band gaps can be tuned up to large values (0.2 eV for HgTe and 0.05 eV for HgSe) by tensile strain, which far exceed those of current experimentally realized 2D quantum spin Hall insulators. Our results suggest a new type of material suitable for practical applications of 2D TI at room-temperature. PMID:26365502

  9. Terlinguacreekite, Hg32+O2 Cl2, a new mineral species from the Perry pit, Mariposa mine, Terlingua mining district, Brewster County, Texas, U.S.A

    USGS Publications Warehouse

    Roberts, Andrew C.; Gault, Robert A.; Paar, W.H.; Cooper, M.A.; Hawthorne, F.C.; Burns, P.C.; Cisneros, S.; Foord, E.E.

    2005-01-01

    Terlinguacreekite, ideally Hg32+O2 Cl2, has a very pronounced subcell that is orthorhombic, space-group choices Imam, Imcm, Ima2 and 12cm, with unit-cell parameters refined from powder data: a 6.737(3), b 25.528(10), c 5.533(2) A??, V951.6(6) A??3, a:b:c 0.2639:1:0.2167, Z=8. The true symmetry, supercell unit-cell parameters, and details regarding the crystal structure are unknown. The strongest nine lines of the X-ray powder-diffraction pattern [d in A?? (I)(subcell hkl)] are: 5.413(30)(011), 4.063(80)(121), 3.201(50)(080), 3.023(50)(161), 2.983(60)(240), 2.858(30)(211), 2.765(50)(002), 2.518(100b)(091, 251) and 2.026(30)(242). The mineral is found in an isolated area measuring approximately 1 ?? 0.5 m in the lower level of the Perry pit, Mariposa mine, Terlingua mining district, Brewster County, Texas (type locality), as mm-sized anhedral dark orange to reddish orange crusts of variable thickness on calcite, and rarely as 0.5 mm-sized aggregates of crystals of the same color. It has also been identified at the McDermitt mine, Humboldt County, Nevada, U.S.A., where it occurs with kleinite and calomel in silicified volcanic rocks and sediments. Terlinguacreekite is a secondary phase, most probably formed from the alteration of primary cinnabar or native mercury. At Terlingua, most crusts are thin, almost cryptocrystalline, with no discernable forms, and are resinous and translucent to opaque. Crystals are up to 0.2 mm in length, subhedral, acicular to prismatic, elongation [001], with a maximum length-to-width ratio of 4:1. They are vitreous, transparent, and some crystals have brightly reflecting faces, which may be {010} and {110}. The streak is yellow, and the mineral is brittle with an uneven fracture, no observable cleavage, and is soft, nonfluorescent under both long- and short-wave ultraviolet light. D (calc.) is 9.899 g/cm3 (empirical formula). Material from the McDermitt mine is reversibly photosensitive, and turns from vivid orange to black in strong

  10. The LLAMA 12 m mm/sub-mm radiotelescope in the Andes

    NASA Astrophysics Data System (ADS)

    Lepine, Jacques; Edemundo Arnal, Marcelo; de Graauw, Thijs; Abraham, Zulema; Gimenez de Castro, Guillermo; de Gouveia Dal Pino, Elisabete; Morras, Ricardo; Larrarte, Juan; Viramontes, José; Finger, Ricardo; Kooi, Jacob; Reeves, Rodrigo; Beaklini, Pedro

    2015-08-01

    LLAMA (Large Latin American Millimetric Array) is a joint Argentinean-Brazilian project of a 12m mm/sub-mm radio telescope similar to the APEX antenna, to be installed at a site at 4800 m altitude near San Antonio de Los Cobres in the Salta Province in Argentine, at 150 km from ALMA. The scientific cases for single dish and VLBI observations include black holes and accretion disks, the molecular evolution of interstellar clouds, the structure of the Galaxy, the formation of galaxies, and much more. The antenna was ordered to the company Vertex Antennentechnik in June 2014, and the construction is progressing quickly; it will be installed at the site in 2016. The radio telescope will be equipped with up to six receivers covering bands similar to those of ALMA. Cryostats with room for 3 cartridges, constructed by NAOJ (Tokyo,Japan), will be installed in each of the two Nasmyth cabins. Among the first receivers we will have an ALMA band 9 provided by NOVA (Groningen, Holland) and a band 5 from the Chalmers University (Sweden). Other receivers are still being discussed at the time of submission of this abstract,At high frequencies, VLBI observations at high frequencies could be made with ALMA, APEX and ASTE, and Northern radiotelescopes. In this way, LLAMA will be a seed for a Latin-American VLBI network.

  11. HgCdTe for NASA EOS missions and detector uniformity benchmarks

    NASA Technical Reports Server (NTRS)

    Norton, Paul R.

    1990-01-01

    Important NASA Earth Observing System (EOS) missions, Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectrometer (MODIS-N), which require detector spectral response in the range of 14 to 17 microns at medium background flux levels and operation in the range of temperatures between 65 to 95 K, will be flown beginning in the next few years. Currently, a prime candidate detector technology for these missions is trapping-mode photoconductive HgCdTe devices. These devices can be tailored to the exact cutoff wavelengths required by those missions, and thus offer the performance advantages of an intrinsic detector which is ideally matched to the mission wavelength. Under the long wavelength-background-temperature conditions of these EOS missions, any detector will at best be thermal generation-recombination noise limited. Photoconductive devices are generally preferred under these circumstances, since at elevated temperatures their performance degrades with n(sub i) while for photovoltaic detectors performance degrades as n sub i(exp 2) n sub i is the intrinsic carrier concentration which is a function of alloy composition and temperature, but not doping. Very high performance trapping-mode photoconductive HgCdTe detectors have been developed which can be reproducibly fabricated. Detectivity (D asterisk) at 80K and 16 micron cutoff wavelength in excess of 10(exp 11) Jones has been measured for these devices. Power dissipation is at least two orders of magnitude less than conventional HgCdTe photoconductors - on the order of 0.12 W/cm(exp 2) compared with 12 W/cm(exp 2). EOS missions define thermal noise limited conditions for the long wavelength operating bands. Trapping-mode photoconductive HgCdTe detectors are linear under such conditions and responsivity is independent of background flux. At lower temperatures or high flux conditions in which background flux limits detector performance, trapping-mode detectors have a responsivity which varies with

  12. Importance of Dissolved Neutral Hg-Sulfides, Energy Rich Organic Matter and total Hg Concentrations for Methyl Mercury Production in Sediments

    NASA Astrophysics Data System (ADS)

    Drott, A.; Skyllberg, U.

    2007-12-01

    Methyl mercury (MeHg) is the mercury form that biomagnifies to the greatest extent in aquatic food webs. Therefore information about factors determining MeHg concentrations is critical for accurate risk assessment of contaminated environments. The concentration of MeHg in wetlands and sediments is the net result of: 1) methylation rates, 2) demethylation rates, and 3) input/output processes. In this study, the main controls on Hg methylation rates and total concentrations of MeHg, were investigated at eight sites in Sweden with sediments that had been subjected to local Hg contamination either as Hg(0), or as phenyl-Hg. Sediments were selected to represent a gradient in total Hg concentration, temperature climate, salinity, primary productivity, and organic C content and quality. Most sediments were high in organic matter content due to wood fibre efflux from pulp and paper industry. The pore water was analysed for total Hg, MeHg, DOC, H2S(aq), pH, DOC, Cl and Br. The chemical speciation of Hg(II) and MeHg in pore water was calculated using equilibrium models. Potential methylation and demethylation rates in sediments were determined in incubation experiments at 23° C under N2(g) for 48 h, after addition of isotopically enriched 201Hg(II) and Me204Hg. In all surface (0-20 cm) sediments there was a significant (p<0.001) positive relationship between the experimentally determined specific potential methylation rate constant (Km, day-1) and % MeHg (concentrations of MeHg normalized to total Hg) in the sediment. This indicates that MeHg production overruled degradation and input/output processes of MeHg in surface sediments, and that % MeHg in surface sediments may be used as a proxy for net production of MeHg. To our knowledge, these are the first data showing significant positive relationships between short term (48 h) MeHg production and longer term accumulation of MeHg, across a range of sites with different properties (1). If MeHg was not normalized to total Hg

  13. Reaction Hg+I/sub 2/. -->. HgI+I revisited

    SciTech Connect

    Oprysko, M.M.; Aoiz, F.J.; McMahan, M.A.; Bernstein, R.B.

    1983-03-15

    The crossed molecular beam study of Mayer et al. (1977) on the subject reaction is revisited. The present work employs a different beam configuration and thus kinematic framework, and a larger range of relative translational energies is covered (i.e., from the threshold of 1.15 to 3.75 eV). Measurements include in-plane angular distributions and relative values of integral reaction cross sections as a function of energy. At low energies, the results of the present experiments are in good agreement with the previous work. Starting at the threshold, the reaction proceeds through the formation of a long-lived complex, presumed to be IHgI. At higher energies, the c.m. angular distributions show a gradual increase of the so-called ''backscattered component.'' This is interpreted as the opening of a new reaction path: the direct-mode abstraction of I via collinear approach of the Hg atom to the I/sub 2/ molecule. The overall dynamics of this reaction are interpreted in the context of the semiempirical potential energy surfaces and electronic state correlation diagrams of Muckerman et al. (1977). From the present experimental results, the height of the barrier in the exit channel for the collinear configuration can be estimated to be in the range 2.0--2.3 eV. The excitation function rises from threshold and reaches a maximum at collision energy of 2.6 eV, falling off monotonically thereafter.

  14. Overcoming phytoremediation limitations. A case study of Hg contaminated soil

    NASA Astrophysics Data System (ADS)

    Barbafieri, Meri

    2013-04-01

    Phytoremediation is a broad term that comprises several technologies to clean up water and soil. Despite the numerous articles appearing in scientific journals, very few field applications of phytoextraction have been successfully realized. The research here reported on Phytoextraction, the use the plant to "extract" metals from contaminated soil, is focused on implementations to overcome two main drawbacks: the survival of plants in unfavorable environmental conditions (contaminant toxicity, low fertility, etc.) and the often lengthy time it takes to reduce contaminants to the requested level. Moreover, to overcome the imbalance between the technology's potential and its drawbacks, there is growing interest in the use of plants to reduce only the fraction that is the most hazardous to the environment and human health, that is to target the bioavailable fractions of metals in soil. Bioavailable Contaminant Stripping (BCS) would be a remediation approach focused to remove the bioavailable metal fractions. BCS have been used in a mercury contaminated soil from Italian industrial site. Bioavailable fractions were determined by sequential extraction with H2O and NH4Cl.Combined treatments of plant hormone and thioligand to strength Hg uptake by crop plants (Brassica juncea and Helianthus annuus) were tested. Plant biomass, evapotranspiration, Hg uptake and distribution following treatments were compared. Results indicate the plant hormone, cytokinine (CK) foliar treatment, increased evapotranspiration rate in both tested plants. The Hg uptake and translocation in both tested plants increased with simultaneous addition of CK and TS treatments. B. juncea was the most effective in Hg uptake. Application of CK to plants grown in TS-treated soil lead to an increase in Hg concentration of 232% in shoots and 39% in roots with respect to control. While H. annuus gave a better response in plant biomass production, the application of CK to plants grown in TS-treated soil lead to

  15. Electronic properties of liquid Hg-In alloys : Ab-initio molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

    2016-05-01

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-In alloys (Hg10In90, Hg30In70,. Hg50In50, Hg70In30, and Hg90Pb10) at 299 K are considered. The calculated results for liquid Hg (l-Hg) and lead (l-In) are also drawn. Along with the calculated results of considered five liquid alloys of Hg-In alloy. The results obtained from electronic properties namely total density of state and partial density of states help to find the local arrangement of Hg and In atoms and the presence of liquid state in the considered five alloys.

  16. Bioaccumulation of Hg in the mushroom Pleurotus ostreatus

    SciTech Connect

    Bressa, G.; Cima, L.; Costa, P.

    1988-10-01

    The possibility of utilizing industrial, urban, and other wastes for the growth of a product which is directly edible by humans is fascinating. However, it is possible that many wastes containing toxic substances, for example, heavy metals, could reach the food chain and produce adverse effects on human health. To this end, we studied the possibility of bioaccumulation of Hg by a mushroom, Pleurotus ostreatus, grown on an artificial compost containing this element. Concentrations of 0.05, 0.1, and 0.2 mg/kg of Hg as Hg(NO/sub 3/)/sub 2/.H/sub 2/O were added to three groups of the same compost, successively inoculated with the mycelia of the mushroom. Higher concentrations strongly reduced the growth of the mycelia and therefore were not utilized. The concentrations of Hg in the substrate and in the mushroom were evaluated by AAS. The range of the accumulation factor was found to be 65-140, i.e., very marked. This finding suggests that the cultivation of P. ostreatus on substrates containing Hg from industrial and urban wastes could involve possible risks to human health.

  17. Defect chemistry and characterization of (Hg, Cd)Te

    NASA Technical Reports Server (NTRS)

    Vydyanath, H. R.

    1981-01-01

    Single crystal samples of phosphorus doped Hg sub 0.8 Cd sub 0.2 Te were anneald at temperatures varying from 450 C to 600 C in various Hg atmospheres. The samples were quenched to room temperature from the annealing temperatures. Hall effect and mobility measurements were performed at 77 K on all these samples. The results indicate the crystals to be p type for a total phosphorus concentration of 10 to the 19th power/cu cm in all the samples. The hole concentration at 77 K increases with increasing Hg pressures at 450 C and 500 C contrary to the observation in undoped crystals. Also, at low Hg pressures the concentration of holes in the phosphorus doped crystals is lower than in the undoped crystals. The hole concentration in all the samples is lower than the intrinsic carrier concentration at the annealing temperatures. The hole mobility in the doped crystals is similar to that in the undoped crystals. A defect model according to which phosphorus behaves as a single acceptor interstitially, occupying Te lattice sites while it acts as a single donor occupying Hg lattice sites was established. Equilibrum constants established for the incorporation of all the phosphorus species explain the experimental results

  18. Teaching Evolutionary Mechanisms: Genetic Drift and M&M's.

    ERIC Educational Resources Information Center

    Staub, Nancy L.

    2002-01-01

    Describes a classroom activity that teaches the mechanism of genetic drift to undergraduates. Illustrates a number of concepts that are critical in developing evolution literacy by sampling M&M milk chocolate candies. (MM)

  19. Crystal structure of Hg2SO4 – a redetermination

    PubMed Central

    Weil, Matthias

    2014-01-01

    The crystal structure of mercury(I) sulfate (or mercurous sulfate), Hg2SO4, was re-determined based on modern CCD data. In comparison with the previous determination from Weissenberg film data [Dorm (1969 ▶). Acta Chem. Scand. 23, 1607–1615], all atoms were refined with anisotropic displacement parameters, leading to higher precision in terms of bond lengths and angles [e.g. Hg—Hg = 2.5031 (7) compared to 2.500 (3)Å]. The structure consists of alternating rows along [001] of Hg2 2+ dumbbells (generated by inversion symmetry) and SO4 2− tetra­hedra (symmetry 2). The dumbbells are linked via short O—Hg—Hg—O bonds to the sulfate tetra­hedra into chains extending parallel to [20-1]. More remote O—Hg—Hg—O bonds connect these chains into a three-dimensional framework. PMID:25309168

  20. Observation of Broadband Ultraviolet Emission from Hg3*

    NASA Astrophysics Data System (ADS)

    Chen, Wenting Wendy; Galvin, Thomas C.; Eden, J. Gary

    2016-06-01

    A previously-unobserved emission continuum, peaking at ˜ 380 nm, has been observed when Hg vapor is photoexcited at 248 nm (KrF laser). Attributed to the mercury trimer, Hg3, this emission continuum has a spectral breadth (FWHM) increased from ˜ 65 to ˜ 90 nm and a decay rate growed from ˜ 6 × 10^3 to ˜ 7 × 10^3 second-1, corresponding to Hg vapor density rising from ˜ 1016 to ˜ 2 × 1019 cm-3. Comparisons of the observed spectra with theory suggest that continuum arises from transitions of the molecule of D∞ h symmetrical linear, D3h equilateral triangular and C2h equilateral triangular configurations. Kitamura, Hikaru. "Theoretical potential energy surfaces for excited mercury trimers." Chemical physics 325.2 (2006): 207-219

  1. Effect of doping on electronic properties of HgSe

    NASA Astrophysics Data System (ADS)

    Nag, Abhinav; Sastri, O. S. K. S.; Kumar, Jagdish

    2016-05-01

    First principle study of electronic properties of pure and doped HgSe have been performed using all electron Full Potential Linearized Augmented Plane Wave (FP-LAPW) method using ELK code. The electronic exchange and co-relations are considered using Generalized Gradient Approach (GGA). Lattice parameter, Density of States (DOS) and Band structure calculations have been performed. The total energy curve (Energy vs Lattice parameter), DOS and band structure calculations are in good agreement with the experimental values and those obtained using other DFT codes. The doped material is studied within the Virtual Crystal Approximation (VCA) with doping levels of 10% to 25% of electrons (hole) per unit cell. Results predict zero band gap in undopedHgSe and bands meet at Fermi level near the symmetry point D. For doped HgSe, we found that by electron (hole) doping, the point where conduction and valence bands meet can be shifted below (above) the fermi level.

  2. Natural Hg isotopic composition of different Hg compounds in mammal tissues as a proxy for in vivo breakdown of toxic methylmercury.

    PubMed

    Perrot, Vincent; Masbou, Jeremy; Pastukhov, Mikhail V; Epov, Vladimir N; Point, David; Bérail, Sylvain; Becker, Paul R; Sonke, Jeroen E; Amouroux, David

    2016-02-01

    In the last decade, specific attention has been paid to total mercury (HgT) stable isotopic composition, especially in natural samples such as aquatic organisms, due to its potential to track the cycle of this toxic element in the environment. Here, we investigated Hg Compound Specific stable Isotopic Composition (CSIC) of natural inorganic Hg (iHg) and methylmercury (MMHg) in various tissues of aquatic mammals (Beluga whale from the Arctic marine environment and seals from the freshwater lake Baikal, Russia). In seals' organs the variation in mass dependent fractionation (MDF, δ(202)Hg) for total Hg was significantly correlated to the respective fraction of iHg and MMHg compounds, with MMHg being enriched by ∼ 3‰ in heavier isotopes relative to iHg. On the other hand, we observe insignificant variation in Hg mass independent isotope fractionation (MIF, Δ(199)Hg) among iHg and MMHg in all organs for the same mammal species and MMHg in prey items. MIF signatures suggest that both MMHg and iHg in aquatic mammals have the same origin (i.e., MMHg from food), and are representative of Hg photochemistry in the water column of the mammal ecosystem. MDF signatures of Hg compounds indicate that MMHg is demethylated in vivo before being stored in the muscle, and the iHg formed is stored in the liver, and to a lesser extent in the kidney, before excretion. Thus, Hg CSIC analysis in mammals can be a powerful tool for tracing the metabolic response to Hg exposure.

  3. Sporadic Creutzfeldt-Jakob Disease MM1+2C and MM1 are Identical in Transmission Properties.

    PubMed

    Kobayashi, Atsushi; Matsuura, Yuichi; Iwaki, Toru; Iwasaki, Yasushi; Yoshida, Mari; Takahashi, Hitoshi; Murayama, Shigeo; Takao, Masaki; Kato, Shinsuke; Yamada, Masahito; Mohri, Shirou; Kitamoto, Tetsuyuki

    2016-01-01

    The genotype (methionine, M or valine, V) at polymorphic codon 129 of the PRNP gene and the type (1 or 2) of abnormal prion protein in the brain are the major determinants of the clinicopathological features of sporadic Creutzfeldt-Jakob disease (CJD), thus providing molecular basis for classification of sporadic CJD, that is, MM1, MM2, MV1, MV2, VV1 or VV2. In addition to these "pure" cases, "mixed" cases presenting mixed neuropathological and biochemical features have also been recognized. The most frequently observed mixed form is the co-occurrence of MM1 and MM2, namely MM1+2. However, it has remained elusive whether MM1+2 could be a causative origin of dura mater graft-associated CJD (dCJD), one of the largest subgroups of iatrogenic CJD. To test this possibility, we performed transmission experiments of MM1+2 prions and a systematic neuropathological examination of dCJD patients in the present study. The transmission properties of the MM1+2 prions were identical to those of MM1 prions because MM2 prions lacked transmissibility. In addition, the neuropathological characteristics of MM2 were totally absent in dCJD patients examined. These results suggest that MM1+2 can be a causative origin of dCJD and causes neuropathological phenotype similar to that of MM1.

  4. Molecular structure of mercurous halides: Hg/sub 2/F/sub 2/ and Hg/sub 2/Cl/sub 2/

    SciTech Connect

    Kleier, D.A.; Wadt, W.R.

    1980-11-05

    Ab initio generalized valence bond calculations using effective core potentials are presented for the ground state of (HgF)/sub 2/ and (HgCl)/sub 2/. Extensive calculations are also reported for HgF and compared with previous literature results for HgCl. In spite of the polar nature of the Hg-X bond in the monomer, which would favor a head-to-tail orientation of the dipoles in the dimer, a moderately strong covalent bond between the mercury atoms dictates a linear structure (X-Hg-Hg-X) for both fluoride and chloride. Comparison with solid-state data suggests that the Hg-X bonds shorten upon entering the gas phase. Stability toward disproportionation is problematical. Simple calculations predict the chloride to be about 0.6 eV more stable than Hg + HgCl/sub 2/, while the disproportionation of Hg/sub 2/F/sub 2/ is predicted to be nearly thermoneutral. Improved calculations shed some doubt on the stability of Hg/sub 2/Cl/sub 2/. An improved virtual orbital calculation has been performed to estimate where spectral evidence for the existence of Hg/sub 2/Cl/sub 2/ in the gas phase might be found. 5 tables. 2 figures.

  5. Hydrothermal synthesis of alpha- and beta-HgS nanostructures

    NASA Astrophysics Data System (ADS)

    Galain, Isabel; María, Pérez Barthaburu; Ivana, Aguiar; Laura, Fornaro

    2017-01-01

    We synthesized HgS nanostructures by the hydrothermal method in order to use them as electron acceptors in hybrid organic-inorganic solar cells. We employed different mercury sources (HgO and Hg(CH3COO)2) and polyvinylpyrrolidone (PVP) or hexadecanethiol (HDT) as stabilizing/capping agent for controlling size, crystallinity, morphology and stability of the obtained nanostructures. We also used thiourea as sulfur source, and a temperature of 180 °C during 6 h. Synthesized nanostructures were characterized by powder X-Ray Diffraction, Diffuse Reflectance Infrared Fourier Transform and Transmission Electron Microscopy. When PVP acts as stabilizing agent, the mercury source has influence on the size -but not in morphology- of the beta-HgS obtained nansostructures. HDT has control over nanostructures' size and depending on the relation Hg:HDT, we obtained a mixture of alpha and beta HgS which can be advantageous in the application in solar cells, due their absorption in different spectral regions. The smallest nanostructures obtained have a mean diameter of 20 nm when using HDT as capping agent. Also, we deposited the aforementioned nanostructures onto flat glass substrates by the spin coating technique as a first approach of an active layer of a solar cell. The depositions were characterized by atomic force microscopy. We obtained smaller particle deposition and higher particle density -but a lower area coverage (5%) - in samples with HDT as capping agent. This work presents promising results on nanostructures for future application on hybrid solar cells. Further efforts will be focused on the deposition of organic-inorganic layers.

  6. Raman spectroscopic investigations of Hg-Cd-Te melts

    NASA Technical Reports Server (NTRS)

    Morrobel-Sosa, Anny

    1987-01-01

    Raman scattering measurements are reported for a series of Hg sub1-xCd subxTe (with x less than or =0.2) materials from 295 K (room temperature) to 1126K (up to and above their liquidus temperatures), and for Hg sub1-xCd subxTe (x=0.3) at 285K. The samples were contained in high-temperature optically-flat fused silica cell. Variable temperature measurements were effected in a three-zone, high-temperature furnace equipped with optical windows, and monitored externally by three independently programmable temperature controllers. All studies were made in the backscattering geometry using the 5145 A line of an Ar+ ion laser, with incident power less than 250 mW, as the excitiation source. An intensity enhancement is observed for a mode in each of the compositions studied. The frequency of this mode varies with composition, 142/cm for HgTe, and 128/cm for both the Hg sub1-xCd subxTe (x=0.053 and 0.204) samples. In addition, a shift to lower frequency as a function of temperature is observed in all samples. This shift is most prominent for the x=0.053 sample. The temperature dependence of these modes as the liquidus temperatures are achieved and surpassed for these samples is presented as being associated with a structural transition in the Hg-rich compositions of the Hg sub1-xCd subxTe series. To our knowledge, this is the first reported study of Raman scattering by phonons in the melts of these materials.

  7. Molecular Beam Epitaxial Growth, Characterization and Electronic Device Processing of HgCdTe, HgZnTe, Related Heterojunctions and HgCdTe-CdTe Superlattices

    DTIC Science & Technology

    1989-11-13

    xI011 40 41 24.4 5 0. 1 0 C1" 166 2.7 x 1016 8.3X 101* 1.5 ... ... 36 27.6 3 3, 10 N. Vde . TomiaL A, VNL , Me. L MAN IM 313 b3oultercthe ofal...growth by molecular beam epitaxy of twin-free CdTe(111)B and HgCdTe(111)B epitaxial layers. HgCdTe( 1 11)B twin-free layers exhibit very different...OCT. 1 , 1987 - SEPT. 30, 1989 DARPA CONTRACT MONITORED BY AFOSR #F49620-87-C-0021 Acesion For 77 FINAL REPORT ?JI R& )TIC TAB J :-"tiicatiuf, 1 Jean

  8. A (201)Hg+ Comagnetometer for (199)Hg+ Trapped Ion Space Atomic Clocks

    NASA Technical Reports Server (NTRS)

    Burt, Eric A.; Taghavi, Shervin; Tjoelker, Robert L.

    2011-01-01

    A method has been developed for unambiguously measuring the exact magnetic field experienced by trapped mercury ions contained within an atomic clock intended for space applications. In general, atomic clocks are insensitive to external perturbations that would change the frequency at which the clocks operate. On a space platform, these perturbative effects can be much larger than they would be on the ground, especially in dealing with the magnetic field environment. The solution is to use a different isotope of mercury held within the same trap as the clock isotope. The magnetic field can be very accurately measured with a magnetic-field-sensitive atomic transition in the added isotope. Further, this measurement can be made simultaneously with normal clock operation, thereby not degrading clock performance. Instead of using a conventional magnetometer to measure ambient fields, which would necessarily be placed some distance away from the clock atoms, first order field-sensitive atomic transition frequency changes in the atoms themselves determine the variations in the magnetic field. As a result, all ambiguity over the exact field value experienced by the atoms is removed. Atoms used in atomic clocks always have an atomic transition (often referred to as the clock transition) that is sensitive to magnetic fields only in second order, and usually have one or more transitions that are first-order field sensitive. For operating parameters used in the (199)Hg(+) clock, the latter can be five orders of magnitude or more sensitive to field fluctuations than the clock transition, thereby providing an unambiguous probe of the magnetic field strength.

  9. HgI2 low energy beta particle detector

    NASA Technical Reports Server (NTRS)

    Shah, K. S.; Squillante, M. R.; Entine, G.

    1990-01-01

    An HgI2 device structure was designed and tested which allows HgI2 to be used to make low-energy beta-particle detectors. The devices detected tritium beta particles with an efficiency of about 25 percent. A protective encapsulant has been developed which should protect the devices for up to 20 years and will attenuate only a small fraction of the beta particles. It is noted that the devices hold significant promise to provide a practical alternative to liquid scintillation counters and gas flow-through proportional counters.

  10. A new HgMn star HD 196821

    NASA Astrophysics Data System (ADS)

    Ćalışkan, Şeyma; Ünal, Özge

    2017-02-01

    In this study, we present the chemical abundance analysis of HD 196821. The spectra of HD 196821 was obtained at the TÜBİTAK National Observatory using the Coudé Echelle spectrograph attached to the 1.5 m telescope. We determined the atmospheric parameters of HD 196821: Teff=10600K, log g=3.6, vmic=0 km/s, and [Fe/H]=0.16 dex. HD 196821 shows an overabundance of 85 times solar for Mn and 208,930 times solar for Hg. This strongly suggests that the star should be classified as an HgMn star.

  11. Increased capabilities of the 30-cm diameter Hg ion thruster

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.; Hawkins, C. E.

    1979-01-01

    Some space flight missions require advanced ion thrusters which operate at conditions much different than those for which the baseline 30-cm Hg thruster was developed. Results of initial tests of a 30-cm Hg thruster with two and three grid ion accelerating systems, operated at higher values of both thrust and power and over a greater range of specific impulse than the baseline conditions are presented. Thruster lifetime at increased input power was evaluated both by extended tests and real time spectroscopic measurements.

  12. Crystal Growth of Solid Solution HgCdTe Alloys

    NASA Technical Reports Server (NTRS)

    Lehoczky, Sandor L.

    1997-01-01

    The growth of homogenous crystals of HgCdTe alloys is complicated by the large separation between their liquidus and solidus temperatures. Hg(1-x)Cd(x)Te is representative of several alloys which have electrical and optical properties that can be compositionally tuned for a number of applications. Limitations imposed by gravity during growth and results from growth under reduced conditions are described. The importance of residual accelerations was demonstrated by dramatic differences in compositional distribution observed for different attitudes of the space shuttle that resulted in different steady acceleration components.

  13. Mercury methylation rates for geochemically relevant Hg(II) species in sediments.

    PubMed

    Jonsson, Sofi; Skyllberg, Ulf; Nilsson, Mats B; Westlund, Per-Olof; Shchukarev, Andrey; Lundberg, Erik; Björn, Erik

    2012-11-06

    Monomethylmercury (MeHg) in fish from freshwater, estuarine, and marine environments is a major global environmental issue. Mercury levels in biota are mainly controlled by the methylation of inorganic mercuric mercury (Hg(II)) to MeHg in water, sediments, and soils. There is, however, a knowledge gap concerning the mechanisms and rates of methylation of specific geochemical Hg(II) species. Such information is crucial for a better understanding of variations in MeHg concentrations among ecosystems and, in particular, for predicting the outcome of currently proposed measures to mitigate mercury emissions and reduce MeHg concentrations in fish. To fill this knowledge gap we propose an experimental approach using Hg(II) isotope tracers, with defined and geochemically important adsorbed and solid Hg(II) forms in sediments, to study MeHg formation. We report Hg(II) methylation rate constants, k(m), in estuarine sediments which span over 2 orders of magnitude depending on chemical form of added tracer: metacinnabar (β-(201)HgS(s)) < cinnabar (α-(199)HgS(s)) < Hg(II) reacted with mackinawite (≡FeS-(202)Hg(II)) < Hg(II) bonded to natural organic matter (NOM-(196)Hg(II)) < a typical aqueous tracer ((198)Hg(NO(3))(2)(aq)). We conclude that a combination of thermodynamic and kinetic effects of Hg(II) solid-phase dissolution and surface desorption control the Hg(II) methylation rate in sediments and cause the large observed differences in k(m)-values. The selection of relevant solid-phase and surface-adsorbed Hg(II) tracers will therefore be crucial to achieving biogeochemically accurate estimates of ambient Hg(II) methylation rates.

  14. 40 CFR 60.4122 - Information requirements for Hg budget permit applications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Information requirements for Hg budget... requirements for Hg budget permit applications. A complete Hg Budget permit application shall include the following elements concerning the Hg Budget source for which the application is submitted, in a...

  15. 40 CFR 60.4121 - Submission of Hg budget permit applications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Submission of Hg budget permit... Times for Coal-Fired Electric Steam Generating Units Permits § 60.4121 Submission of Hg budget permit applications. (a) Duty to apply. The Hg designated representative of any Hg Budget source required to have...

  16. Purification of HgI.sub.2 for nuclear detector fabrication

    DOEpatents

    Schieber, Michael M.

    1978-01-01

    A process for purification of mercuric iodide (HgI.sub.2) to be used as a source material for the growth of detector quality crystals. The high purity HgI.sub.2 raw material is produced by a combination of three stages: synthesis of HgI.sub.2 from Hg and I.sub.2, repeated sublimation, and zone refining.

  17. 40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Calculation of Hg mass emissions and... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Hg Mass Emission Provisions § 75.83 Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass...

  18. Determination of Cd, Cr, Hg and Pb in plastics from waste electrical and electronic equipment by inductively coupled plasma mass spectrometry with collision-reaction interface technology.

    PubMed

    Santos, Mirian C; Nóbrega, Joaquim A; Cadore, Solange

    2011-06-15

    A procedure based on the use of a quadrupole inductively coupled plasma-mass spectrometer equipped with a collision-reaction interface (CRI) for control of spectral overlap interferences was developed for simultaneous determination of Cd, Cr, Hg, and Pb in plastics from waste electrical and electronic equipment (WEEE). The injection of H(2) and He (80 and 60 mL min(-1), respectively) into the sampled plasma, colliding and reacting with potentially interfering polyatomic ions, allows interference-free determination of chromium via its isotopes (52)Cr and (53)Cr that are freed from overlap due to the occurrence of (40)Ar(12)C(+), (40)Ar(12)C(1)H(+), (36)S(16)O(+) or (1)H(36)S(16)O(+). Cadmium, Hg and Pb were directly determined via their isotopes (110)Cd, (111)Cd, (112)Cd, (199)Hg, (200)Hg, (201)Hg, (202)Hg, (206)Pb, (207)Pb, and (208)Pb, without using CRI. The CRI can be quickly activated or deactivated before each analyte measurement. Limits of detection for (52)Cr were 0.04 or 0.14 μg L(-1) with He or H(2) injected in CRI. Cadmium and Pb have LODs between 0.02 and 0.08 μg L(-1) and Hg had 0.93-0.98 μg L(-1), without using CRI. Analyte concentrations for samples varied from 16 to 43, 1 to 11, 4 to 12, and 5 to 13 mg kg(-1) for Cr, Cd, Hg and Pb, respectively.

  19. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  20. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  1. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  2. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  3. Dissolution of cinnabar (HgS) in the presence of natural organic matter

    USGS Publications Warehouse

    Waples, J.S.; Nagy, K.L.; Aiken, G.R.; Ryan, J.N.

    2005-01-01

    Cinnabar (HgS) dissolution rates were measured in the presence of 12 different natural dissolved organic matter (DOM) isolates including humic, fulvic, and hydrophobic acid fractions. Initial dissolution rates varied by 1.3 orders of magnitude, from 2.31 ?? 10-13 to 7.16 ?? 10-12 mol Hg (mg C)-1 m-2 s-1. Rates correlate positively with three DOM characteristics: specific ultraviolet absorbance (R2 = 0.88), aromaticity (R2 = 0.80), and molecular weight (R2 = 0.76). Three experimental observations demonstrate that dissolution was controlled by the interaction of DOM with the cinnabar surface: (1) linear rates of Hg release with time, (2) significantly reduced rates when DOM was physically separated from the surface by dialysis membranes, and (3) rates that approached constant values at a specific ratio of DOM concentration to cinnabar surface area, suggesting a maximum surface coverage by dissolution-reactive DOM. Dissolution rates for the hydrophobic acid fractions correlate negatively with sorbed DOM concentrations, indicating the presence of a DOM component that reduced the surface area of cinnabar that can be dissolved. When two hydrophobic acid isolates that enhanced dissolution to different extents were mixed equally, a 20% reduction in rate occurred compared to the rate with the more dissolution-enhancing isolate alone. Rates in the presence of the more dissolution-enhancing isolate were reduced by as much as 60% when cinnabar was prereacted with the isolate that enhanced dissolution to a lesser extent. The data, taken together, imply that the property of DOM that enhances cinnabar dissolution is distinct from the property that causes it to sorb irreversibly to the cinnabar surface. Copyright ?? 2005 Elsevier Ltd.

  4. Dissolution of cinnabar (HgS) in the presence of natural organic matter

    NASA Astrophysics Data System (ADS)

    Waples, Jacob S.; Nagy, Kathryn L.; Aiken, George R.; Ryan, Joseph N.

    2005-03-01

    Cinnabar (HgS) dissolution rates were measured in the presence of 12 different natural dissolved organic matter (DOM) isolates including humic, fulvic, and hydrophobic acid fractions. Initial dissolution rates varied by 1.3 orders of magnitude, from 2.31 × 10 -13 to 7.16 × 10 -12 mol Hg (mg C) -1 m -2s -1. Rates correlate positively with three DOM characteristics: specific ultraviolet absorbance (R 2 = 0.88), aromaticity (R 2 = 0.80), and molecular weight (R 2 = 0.76). Three experimental observations demonstrate that dissolution was controlled by the interaction of DOM with the cinnabar surface: (1) linear rates of Hg release with time, (2) significantly reduced rates when DOM was physically separated from the surface by dialysis membranes, and (3) rates that approached constant values at a specific ratio of DOM concentration to cinnabar surface area, suggesting a maximum surface coverage by dissolution-reactive DOM. Dissolution rates for the hydrophobic acid fractions correlate negatively with sorbed DOM concentrations, indicating the presence of a DOM component that reduced the surface area of cinnabar that can be dissolved. When two hydrophobic acid isolates that enhanced dissolution to different extents were mixed equally, a 20% reduction in rate occurred compared to the rate with the more dissolution-enhancing isolate alone. Rates in the presence of the more dissolution-enhancing isolate were reduced by as much as 60% when cinnabar was prereacted with the isolate that enhanced dissolution to a lesser extent. The data, taken together, imply that the property of DOM that enhances cinnabar dissolution is distinct from the property that causes it to sorb irreversibly to the cinnabar surface.

  5. Isotopic Composition of Gaseous Elemental Mercury (Hg0) at Various Sites in Japan

    NASA Astrophysics Data System (ADS)

    Yamakawa, A.; Moriya, K.; Yoshinaga, J.

    2015-12-01

    Mercury (Hg) is a toxic heavy metal, which exists in various chemical forms in the environmental system. In the atmosphere, Hg exists in three forms (Hg0(g), Hg+2(g), and Hg(p)). Hg0(g) is the dominant species of atmospheric Hg, accounting for >95% of the total Hg in the atmosphere. Because Hg0(g) is highly volatile and has limited solubility in water, it cannot be easily removed by wet or dry deposition processes. Therefore, the residence time of Hg0(g) in the atmosphere is relatively long (1 to 2 years), allowing long-range transport from mercury emission source(s). Conversely, Hg+2(g) and Hg(p) are effectively removed from the atmosphere through wet and dry depositions. The determination of mercury source attribution using quantitative data is challenging because Hg0(g) may be deposited on an area upon oxidation to Hg+2(g) and associated with aerosols and particulates to form Hg(p) while the global cycling of Hg0(g). Over the last decade, the development of analytical methods of highly precise Hg isotopic measurements demonstrated mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) of Hg isotopes in environmental samples. For instance, MDF of Hg isotopes is thought to occur during various natural and industrial Hg transformations. MIF of Hg isotopes is observed during abiotic reduction, photochemical and non-photochemical, and physical and chemical processes. Such processes lead to differences in the Hg isotopic composition of different emission sources, both natural and anthropogenic, and atmospheric processes (i.e., transportation, oxidation/reduction, deposition, and reemission). Therefore, Hg isotopic compositions could be used to trace the sources and processes of atmospheric Hg. For securing the reliability and accuracy of atmospheric Hg isotope data, the methods of collection, pretreatment, and isotopic measurement for Hg0(g) were developed to obtain high recovery yield of samples with no Hg isotopic fractionation during each

  6. Thermodynamics limits the reactivity of BrHg radical with volatile organic compounds

    NASA Astrophysics Data System (ADS)

    Dibble, Theodore S.; Schwid, Abraham C.

    2016-08-01

    Mercury emissions to the atmosphere primarily consist of Hg(0), which tends not to enter ecosystems until it is oxidized. Atomic bromine initiates oxidation of Hg(0) via the BrHg intermediate, but the further reactions of BrHg are just beginning to be explored. Here we use quantum chemistry to determine that hydrogen abstraction from hydrocarbons by BrHg is so endothermic as to be irrelevant. Bonds between BrHg and carbon atoms are so weak that BrHg addition to carbon-carbon double bonds atoms will be somewhat ineffective in leading to further reactions.

  7. High-value utilization of lignin to synthesize Ag nanoparticles with detection capacity for Hg²⁺.

    PubMed

    Shen, Zuguang; Luo, Yuqiong; Wang, Qun; Wang, Xiaoying; Sun, Runcang

    2014-09-24

    This study reports the rapid preparation of silver nanoparticles (AgNPs) from Tollens' reagent under microwave irradiation. In the synthesis, lignin with reducing groups and spatial three-dimensional structure was used as reducing and stabilizing agents without other chemical reagents, and the effects of the ratio of lignin to Ag(+), reaction temperature, and heating time on the synthesis of AgNPs were investigated. The obtained AgNPs were further characterized by UV-vis, Malvern particle size, TEM, XRD, and XPS analyses. The structural changes of lignin before and after reaction were also studied by FT-IR, (1)H NMR, (13)C NMR, and GC-MS. The results revealed that the obtained AgNPs were mostly spherical with diameters of around 24 nm. The optimum reaction conditions were a ratio 50 mg of lignin to 0.3 mM of Ag(+), a microwave irradiation temperature of 60 °C, and a heating time of 10 min. Moreover, AgNPs redispersed well in water and ethanol after centrifugation for the removal of lignin. During the formation of AgNPs, lignin was oxidized, and the side chains of lignin were partly disrupted into small molecules, such as hydrocarbon and alcohol. The resultant lignin-AgNPs showed highly selective sensing detection for Hg(2+), and the color of the lignin-AgNP solution containing Hg(2+) decreased gradually with increasing amounts of Hg(2+) within seconds, but the other 19 metal ions had little effect on the color and surface plasmon absorption band of the lignin-AgNPs. Also, there was a linear relationship between the absorbance and Hg(2+) concentration, with a limit of detection concentration of 23 nM. This study provides not only a new way to take advantage of agricultural and forestry residues, but also a green and rapid method for the synthesis of AgNPs to detect the toxic ion Hg(2+) selectively and sensitively.

  8. Luteolin and thiosalicylate inhibit HgCl(2) and thimerosal-induced VEGF release from human mast cells.

    PubMed

    Asadi, S; Zhang, B; Weng, Z; Angelidou, A; Kempuraj, D; Alysandratos, K D; Theoharides, T C

    2010-01-01

    HgCl2 is a known environemental neurotoxin, but is also used as preservative in vaccines as thimerosal containing ethyl mercury covalently linked to thiosalicylate. We recently reported that mercury choloride (HgCl(2)) can stimulate human mast cells to release vascular endothelial growth factor (VEGF), which is also vasoactive and pro-inflammatory. Here we show that thimerosal induces significant VEGF release from human leukemic cultured LAD2 mast cells (at 1 microM 326 ± 12 pg/106 cells and 335.5 ± 12 pg/106 cells at 10 microM) compared to control cells (242 ± 21 pg/106 cells, n=5, p less than 0.05); this effect is weaker than that induced by HgCl2 at 10 microM (448 ± 14 pg/106 cells) (n=3, p less than 0.05). In view of this finding, we hypothesize that the thiosalicylate component of thimerosal may have an inhibitory effect on VEGF release. Thimerosal (10 microM) added together with the peptide Substance P (SP) at 2 microM, used as a positive control, reduced VEGF release by 90 percent. Methyl thiosalicylate (1 or 10 microM) added with either SP or HgCl2 (10 microM) inhibited VEGF release by 100 percent, while sodium salicylate or ibuprofen had no effect. Pretreatment for 10 min with the flavonoid luteolin (0.1 mM) before HgCl2 or thimerosal compeletly blocked their effect. Luteolin and methyl thiosalicylate may be useful in preventing mercury-induced toxicity.

  9. Variation of magnetic properties with mischmetal content in the resource saving magnets of MM-Fe-B ribbons

    NASA Astrophysics Data System (ADS)

    Li, Zhu-bai; Wang, Li-chen; Geng, Xiao-peng; Hu, Feng-xia; Sun, Ji-rong; Shen, Bao-gen

    2017-03-01

    Magnetic materials of MM-Fe-B (MM=mischmetal) ribbons were prepared using melt spinning method by varying the content of MM. The ribbons contain minor phases besides the main phase of Re2Fe14B. X-ray techniques show that the diffraction peak intensities of the minor phase Fe3B vary with the content of constituent elements, indicating that the amount of minor phase could be tunable. The squareness of hysteresis loop is the best in MM13Fe80.5B6.5 ribbons, which should mainly ascribe to the less amount of minor phase. Henkel plots verify the more uniform magnetization reversals in MM13Fe80.5B6.5 ribbons, and the energy product achieves to the maximum of 12.74 MGOe with the coercivity of 6.50 kOe. With the increase of MM content the coercivity increases monotonically, and reaches to 9.13 kOe in MM15Fe77.5B7.5 ribbons, which should be related with the nature of the defects in the main phase. These investigations show that optimizing the content of constituent elements and phase constitution could improve magnetic properties in the resource-saving magnets of MM-Fe-B ribbons.

  10. Morphological evaluation of eccentric sets guide-plates of dcp-l 4.5 mm

    PubMed Central

    Borges, José Humberto de Souza; da Silva Filho, Antonio Lisboa; Pereira Neto, Francisco; Daher, Walter Rodrigo; de Mesquita, Alessandro Queiroz; Freitas, Anderson

    2012-01-01

    Objective To carry out isolated and comparative evaluations of the measurements of the set eccentric guide plates used in 4.5mm surgical implants, and to determine the effect of these measurements on compression strength. Methods Four eccentric guides, four large dynamic compression plates (L-DCP) from four local manufacturers, and a Vonder® 200 mm caliper brand were used. Five standard parameter measurements were created for the set eccentric guide-plate, which were identified as A to E. Four sets were made, using materials of the same factory, and identified as groups I to IV. The analyses were performed by measuring all the parameters from a ventral view of the plate, with the eccentric guide placed in the plate hole. Results Groups I and II showed the same values for all the parameters. All the groups showed the same measurements for E = 8.15 e B = 3.60. Group III: A = 8.10mm, C = 3.25mm, D = 1.25mm. Group IV: A = 7.00mm, C = 3.10mm, D = 0.30mm. Maximum compression force was (F Max.): Group I 80.58 N, Group. II: F Max. 81.63 N, Group. III: F Max. 36.32N, Group. IV: F Max. 37.52N Conclusion The measurements evaluated show a lack of standardization in the manufacture of orthopedic instruments and its effects on the values for compression strength. Level of Evidence: Level III, analytical study. PMID:24453573

  11. Photocurrent enhancement of HgTe quantum dot photodiodes by plasmonic gold nanorod structures.

    PubMed

    Chen, Mengyu; Shao, Lei; Kershaw, Stephen V; Yu, Hui; Wang, Jianfang; Rogach, Andrey L; Zhao, Ni

    2014-08-26

    The near-field effects of noble metal nanoparticles can be utilized to enhance the performance of inorganic/organic photosensing devices, such as solar cells and photodetectors. In this work, we developed a well-controlled fabrication strategy to incorporate Au nanostructures into HgTe quantum dot (QD)/ZnO heterojunction photodiode photodetectors. Through an electrostatic immobilization and dry transfer protocol, a layer of Au nanorods with uniform distribution and controllable density is embedded at different depths in the ZnO layer for systematic comparison. More than 80 and 240% increments of average short-circuit current density (Jsc) are observed in the devices with Au nanorods covered by ∼7.5 and ∼4.5 nm ZnO layers, respectively. A periodic finite-difference time-domain (FDTD) simulation model is developed to analyze the depth-dependent property and confirm the mechanism of plasmon-enhanced light absorption in the QD layer. The wavelength-dependent external quantum efficiency spectra suggest that the exciton dissociation and charge extraction efficiencies are also enhanced by the Au nanorods, likely due to local electric field effects. The photodetection performance of the photodiodes is characterized, and the results show that the plasmonic structure improves the overall infrared detectivity of the HgTe QD photodetectors without affecting their temporal response. Our fabrication strategy and theoretical and experimental findings provide useful insight into the applications of metal nanostructures to enhance the performance of organic/inorganic hybrid optoelectronic devices.

  12. Persistent photoconductivity of amorphous Hg0.78Cd0.22Te:In films

    NASA Astrophysics Data System (ADS)

    Lianjie, Yu; Yuhui, Su; Yanli, Shi; Xiongjun, Li; Weiyan, Zhao; Qi, Ma; Yunjian, Tai; Peng, Zhao

    2016-10-01

    The persistent photoconductivity (PPC) of amorphous Hg0.78Cd0.22Te: In films has been studied under illumination by super-bandgap light (a He-Ne laser, hv = 1.96 eV, 30 mW/cm2) and sub-bandgap light (1000 K Blackbody source, the largest photon energies hv p = 0.42 eV, 8.9 mW/cm2) in the range of 80-300 K. The persistent photoconductivity effect increases with increase in illumination intensity and illumination time. However, it decreases with increase in working temperature. The non-exponential decay of photoconductivity implies the presence of continuous distribution of defect states in amorphous Hg0.78Cd0.22Te: In films. These results indicate that the decay of photoconductivity is not governed by the carrier trapped in the intrinsic defects, but it may be due to light-induced defects under light illumination. Project supported by the Natural Science Foundation of Yunnan Province (No. 2008CD176).

  13. Decay from the superdeformed bands in {sup 194}Hg

    SciTech Connect

    Henry, R.G.; Khoo, T.L.; Carpenter, M.P.

    1995-08-01

    Superdeformed bands in {sup 194}H g were studied using the early implementation of Gammasphere. The response functions for the Ge detectors were measured for the first time as part of this experiment. Experiments were performed with both a backed target (where the residue stopped in the Au backing) and a thin target (where the residue recoiled into vacuum). This will permit measurements of the decay times of the quasicontinuum {gamma}rays. The spectrum in coincidence with the yrast SD band in {sup 194}Hg reveals the same features as found in the quasicontinuum structure in {sup 192}Hg. These features include: statistical {gamma}rays feeding the SD band, a pronounced E2 peak from transitions feeding the SD band, a Ml/E2 bump at low energies that is associated with the last stages of feeding of the superdeformed band, and a quasicontinuous distribution from {gamma}rays linking SD and normal states, including a sizable clustering of strength around 1.7 MeV. The remarkable similarity of the spectra coincident with SD bands in {sup 192,194}Hg provides additional support for a statistical process for decay out of the SD states. This similarity contrasts with differences observed in the spectrum coincident with the SD band in the odd-even {sup 191}Hg, confirming the predictions about the role of pairing (in normal states) in influencing the shape of the decay-out spectrum.

  14. The Abundance and Isotopic Composition of Hg in Extraterrestrial Materials

    NASA Technical Reports Server (NTRS)

    Lauretta, D. S.

    2004-01-01

    During the past three year grant period we made excellent progress in our study of the abundances and isotopic compositions of Hg and other volatile trace elements in extraterrestrial materials. As part of my startup package I received funds to construct a state-of-the-art experimental facility to study gas-solid reaction kinetics. Much of our effort was spent developing the methodology to measure the abundance and isotopic composition of Hg at ultratrace levels in solid materials. In our first study, the abundance and isotopic composition of Hg was determined in bulk samples of the Murchison (CM) and Allende (CV) carbonaceous chondrites. We have continued our study of mercury in primitive meteorites and expanded the suite of meteorites to include other members of the CM and CV chondrite group as well as CI and CO chondrites. Samples of the CI chondrite Orgueil, the CM chondrites Murray, Nogoya, and Cold Bokkeveld, the CO chondrites Kainsaz, Omans, and Isna, and the CV chondrites Vigarano, Mokoia, and Grosnaja were tested. We have developed a thermal analysis ICP-MS technique and applied it to the study of a suite of thermally labile elements (Zn, As, Se, Cd, In, Sn, Sb, Te, Hg, Au, Tl, Pb, and Bi) in geologic materials as well.

  15. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS... heating boilers, hot water boilers (which include hot water heating boilers and hot water supply...

  16. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS... heating boilers, hot water boilers (which include hot water heating boilers and hot water supply...

  17. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS... heating boilers, hot water boilers (which include hot water heating boilers and hot water supply...

  18. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS... heating boilers, hot water boilers (which include hot water heating boilers and hot water supply...

  19. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING HEATING BOILERS... heating boilers, hot water boilers (which include hot water heating boilers and hot water supply...

  20. Frequency Comparison of Al+ and Hg+ Optical Standards

    NASA Astrophysics Data System (ADS)

    Rosenband, T.; Hume, D. B.; Brusch, A.; Lorini, L.; Schmidt, P. O.; Fortier, T. M.; Stalnaker, J. E.; Diddams, S. A.; Newbury, N. R.; Swann, W. C.; Oskay, W. H.; Itano, W. M.; Wineland, D. J.; Bergquist, J. C.

    2008-04-01

    We compare the frequencies of two single ion frequency standards: 27Al+ and 199Hg+. Systematic fractional frequency uncertainties of both standards are below 10-16, and the statistical measurement uncertainty is below 5 × 10-17. Recent ratio measurements show a reproducibility that is better than 10-16.

  1. CTB 80 en bajas frecuencias

    NASA Astrophysics Data System (ADS)

    Castelletti, G.; Dubner, G.; Golap, H.; Goss, W. M.

    CTB 80 is a supernova remnant (SNR) which shows, in radio wavelengths, a complex morphology composed by three arms or extended regions and a central nebula formed by winds from the pulsar PSR B1951+32 physically associated with the remnant. New observations of the SNR CTB 80 have been carried out using the Giant Metrewave Radio Telescope (GMRT, Pune-India) at 240 MHz (beam ˜ 20'') and 618 MHz (beam ˜ 8''), and at 324 MHz (beam ˜ 65'') and 1380 MHz (beam ˜ 80'') using the Very Large Array (VLA, USA). These radio-images show with unprecedented detail new structures in the nebula powered by the pulsar. Likewise, the high dynamic range attained in the images allows us identify faint structures in the extended regions which closely match the optical and infrared emission.

  2. A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420⋆

    PubMed Central

    Quintana-Lacaci, G.; Agúndez, M.; Cernicharo, J.; Bujarrabal, V.; Sánchez Contreras, C.; Castro-Carrizo, A.; Alcolea, J.

    2016-01-01

    Aims Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3 mm atmospheric windows. Methods We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N2H+. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account. Results We have found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars. This result supports the presence of a N-rich chemistry, expected for massive stars. Our analysis also suggests a decrease of the 12C/13C ratio from ≳ 7 to ~ 3.7 in the last 3800 years, which can be directly related to the nitrogen enrichment observed. In addition, we found that SiO emission presents a significant intensity decrease for high-J lines when compared with older observations. Radiative transfer modeling shows that this variation can be explained by a decrease in the infrared (IR) flux of the dust. The origin of this decrease might be an expansion of the dust shell or a lower stellar temperature due to the pulsation of the star. PMID:27458319

  3. Growth, properties and applications of HgCdTe

    NASA Astrophysics Data System (ADS)

    Schmit, J. L.

    1983-12-01

    This paper provides primarily a review of the methods used to grow HgCdTe with a summary of some of its basic properties and applications. Methods of crystal growth fall generally into three classes: growth from the melt, from solution and from the vapor phase. All three methods have been and are being used to grow HgCdTe. The high vapor pressure of HgCdTe at the melting point, combined with a large segregation coefficient, have effectively limited the use of Czochralski or zone melting techniques, but two melt growth techniques have survived: (1) a variation of Bridgman growth called quench-anneal wherein a dendritic crystal is formed by quenching the melt and is homogenized by solid state recrystallization below the melting point, (2) a variation of freezing from a large volume called slush-growth wherein a melt is held in a temperature gradient for several weeks while a crystal grows. Growth from solution has taken the form of liquid phase epitaxy (LPE) on CdTe with the LPE systems including growth from Hg-rich, HgTe-rich and Te-rich solutions and using tipping, vertical dipping, vertical sliding and horizontal sliding. Vapor phase growth is very promising but is not yet in production. Techniques include growth by isothermal close spaced epitaxy in which HgTe is transported isothermally by chemical potential onto CdTe, molecular beam epitaxy (MBE) in which elements are evaporated in a high vacuum, and metal organic chemical vapor deposition (MOCVD) in which some of the metal atoms are carried to the substrate bound to organic radicals before being freed by pyrolysis. In all these methods, control of Hg pressure is a major concern. The fundamental properties discussed briefly are those of prime interest to detector manufacturers: energy gap ( Eg), intrinsic carrier concentration ( ni), and electrical activity of dopants. A reasonable fit to the Eg data from ˜ 20 papers is given by Eg = -0.302+1.93x+5.35×10 -4T(1-2x)-0.810x 2+0.832x 3. This gap, combined with k

  4. Comparison of the characteristics and mechanisms of Hg(II) sorption by biochars and activated carbon.

    PubMed

    Xu, Xiaoyun; Schierz, Ariette; Xu, Nan; Cao, Xinde

    2016-02-01

    Two biochars were produced from bagasse and hickory chips (referred to as BB and HCB, respectively) and evaluated for their sorption ability of Hg(II) in aqueous solution. A commercial activated carbon (AC) which is commonly used for Hg(II) removal was included for comparison. Both biochars showed higher sorption capacities than AC, following the trend of BB>HCB>AC. The sorption of Hg(II) by BB and AC was mainly attributed to the formation of (COO)2Hg(II) and (O)2Hg(II). As a result, the adsorption capacity of Hg(II) by BB decreased 17.6% and 37.6% after COOH and OH were blocked, respectively and that of Hg(II) by AC decreased 6.63% and 62.2% for COOH and OH hindered, respectively. However, blocking the function groups had little effect on the Hg removal by HCB since sorption of Hg(II) by HCB was mainly resulted from the π electrons of CC and CO induced Hg-π binding. Further X-ray photoelectron spectroscopy analysis indicated the possibility of reduction of the Hg(II) to Hg(I) by phenol groups or π electrons during the removal of Hg(II) by both biochars. In conclusion, biochar is more effective than activated carbon in removing Hg(II) and there exists a high potential that biochar can be a substitute of activated carbon for removal of Hg(II) from wastewater.

  5. Elemental Mercury in Natural Waters: Occurrence and Determination of Particulate Hg(0).

    PubMed

    Wang, Yongmin; Li, Yanbin; Liu, Guangliang; Wang, Dingyong; Jiang, Guibin; Cai, Yong

    2015-08-18

    Elemental mercury, Hg(0), is ubiquitous in water and involved in key Hg biogeochemical processes. It is extensively studied as a purgeable dissolved species, termed dissolved gaseous mercury (DGM). Little information is available regarding nonpurgeable particulate Hg(0) in water, Hg(0) bound to suspended particulate matter (SPM), which is presumably present due to high affinity of Hg(0) adsorption on solids. By employing stable isotope tracer and isotope dilution (ID) techniques, we investigated the occurrence and quantification of particulate Hg(0) after Hg(0) being spiked into natural waters, aiming to provide firsthand information on particulate Hg(0) in water. A considerable fraction of (201)Hg(0) spiked in water (about 70% after 4 h equilibration) was bound to SPM and nonpurgeable, suggesting the occurrence of particulate Hg(0) in natural waters. A scheme, involving isotope dilution, purge and trap, and inductively coupled plasma mass spectrometry detection, was proposed to quantify particulate Hg(0) by the difference between DGM and total Hg(0), determined immediately and at equilibration after spiking ID Hg isotope, respectively. The application of this newly established method revealed the presence of particulate Hg(0) in Florida Everglades water, as the determined DGM levels (0.14 to 0.22 ng L(-1)) were remarkably lower than total Hg(0) (0.41 to 0.75 ng L(-1)).

  6. Low dark current LWIR HgCdTe focal plane arrays at AIM

    NASA Astrophysics Data System (ADS)

    Haiml, M.; Eich, D.; Fick, W.; Figgemeier, H.; Hanna, S.; Mahlein, M.; Schirmacher, W.; Thöt, R.

    2016-05-01

    Cryogenically cooled HgCdTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices, and fast response times, hence outperforming micro-bolometer arrays. AIM will present its latest results on n-on-p as well as p-on-n low dark current planar MCT photodiode focal plane detector arrays at cut-off wavelengths >11 μm at 80 K. Dark current densities below the Rule'07 have been demonstrated for n-on-p devices. Slightly higher dark current densities and excellent cosmetics with very low cluster and point defect densities have been demonstrated for p-on-n devices.

  7. Relativity and the TRS-80.

    ERIC Educational Resources Information Center

    Levin, Sidney

    1984-01-01

    Presents the listing (TRS-80) for a computer program which derives the relativistic equation (employing as a model the concept of a moving clock which emits photons at regular intervals) and calculates transformations of time, mass, and length with increasing velocities (Einstein-Lorentz transformations). (JN)

  8. Census '80 Projects for Students.

    ERIC Educational Resources Information Center

    Bureau of the Census (DOC), Washington, DC. Data User Services Div.

    This workbook contains exercises for use with college students to teach them about the use of census data and to help them acquire census related skills. The workbook supplements "Census '80: Continuing the Factfinder Tradition," an undergraduate textbook published in early 1980. The volume is divided into two parts. The first provides an overview…

  9. STS-80 Post Flight Presentation

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The flight crew of STS-80, Cmdr. Kenneth D. Cockrell, Pilot Kent V. Rominger, Mission Specialists, Tamara E. Jernigan, Thomas D. Jones, and F. Story Musgrave give a post flight presentation of their mission. This presentation is divided into two parts first a slide presentation of still shots, and the second is a video presentation.

  10. Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l)

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.

    2002-01-01

    Optical absorption spectra of the vapor phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the vapor pressure of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of vaporization and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.

  11. Survival and growth of age-0 steelhead after surgical implantation of 23-mm passive integrated transponders

    USGS Publications Warehouse

    Bateman, D.S.; Gresswell, R.E.

    2006-01-01

    Little information is available on the effects of implanting 23-mm passive integrated transponder (PIT) tags in salmonids less than 90 mm fork length (FL). Using juvenile steelhead Oncorhynchus mykiss (range, 73–97 mm FL), we compared instantaneous growth rates and survival among three experimental groups: control, surgery with no tag, and surgery with tag. Survival rate was lower for tagged fish (86%) than for control and surgery−no tag fish (virtually 100% in each group). Approximately 90% of the mortalities occurred during days 1–3. Growth rate for the tagged group was lower for the first two 10-d measurement intervals; however, during the third 10-d interval, growth rates for tagged fish equaled or exceeded values for the other groups. These results suggest that tagged fish recovered by day 20. Growth rates for the control and surgery−no tag groups did not differ from one another during any measurement interval. Tag retention rate was 97% over the 30-d period of the study. It appears that the combination of fish length and tag size in this study resulted in short-term negative effects on growth rate and survival; however, 23-mm PIT tags may still be useful for studies of salmonids 80–90 mm FL when survival is not the parameter of interest.

  12. High removal efficacy of Hg(II) and MeHg(II) ions from aqueous solution by organoalkoxysilane-grafted lignocellulosic waste biomass.

    PubMed

    Saman, Norasikin; Johari, Khairiraihanna; Song, Shiow-Tien; Kong, Helen; Cheu, Siew-Chin; Mat, Hanapi

    2017-03-01

    An effective organoalkoxysilanes-grafted lignocellulosic waste biomass (OS-LWB) adsorbent aiming for high removal towards inorganic and organic mercury (Hg(II) and MeHg(II)) ions was prepared. Organoalkoxysilanes (OS) namely mercaptoproyltriethoxylsilane (MPTES), aminopropyltriethoxylsilane (APTES), aminoethylaminopropyltriethoxylsilane (AEPTES), bis(triethoxysilylpropyl) tetrasulfide (BTESPT), methacrylopropyltrimethoxylsilane (MPS) and ureidopropyltriethoxylsilane (URS) were grafted onto the LWB using the same conditions. The MPTES grafted lignocellulosic waste biomass (MPTES-LWB) showed the highest adsorption capacity towards both mercury ions. The adsorption behavior of inorganic and organic mercury ions (Hg(II) and MeHg(II)) in batch adsorption studies shows that it was independent with pH of the solutions and dependent on initial concentration, temperature and contact time. The maximum adsorption capacity of Hg(II) was greater than MeHg(II) which respectively followed the Temkin and Langmuir models. The kinetic data analysis showed that the adsorptions of Hg(II) and MeHg(II) onto MPTES-LWB were respectively controlled by the physical process of film diffusion and the chemical process of physisorption interactions. The overall mechanism of Hg(II) and MeHg(II) adsorption was a combination of diffusion and chemical interaction mechanisms. Regeneration results were very encouraging especially for the Hg(II); this therefore further demonstrated the potential application of organosilane-grafted lignocellulosic waste biomass as low-cost adsorbents for mercury removal process.

  13. Simultaneous removal of SO{sub 2}, NOx, and Hg from coal flue gas using a NaClO{sub 2}-enhanced wet scrubber

    SciTech Connect

    Hutson, N.D.; Krzyzynska, R.; Srivastava, R.K.

    2008-08-15

    A bench-scale study was conducted on the simultaneous removal Of SO{sub 2}, NOx, and mercury (both Hg{sup 0} and Hg{sup 2+}) from a simulated coal flue gas using a wet calcium carbonate scrubber. The multipollutant capacity of the scrubber was enhanced with the addition of the oxidizing salt, sodium chlorite. The results showed a maximum scrubbing of 100% for SO{sub 2} and Hg species and near complete NO oxidation with about 60% scrubbing of the resulting NOx species. The chlorite additive was less effective as an oxidant in the absence of SO{sub 2} and NO in the flue gas. Oxidation of NO and mercury were only about 50% and 80%, respectively, in the case of no SO{sub 2} in the simulated flue gas. The mercury oxidation was similarly affected by the absence of NO in the flue gas.

  14. Study of atomic structure of liquid Hg-In alloys using ab-initio molecular dynamics

    SciTech Connect

    Sharma, Nalini; Ahluwalia, P. K.; Thakur, Anil

    2015-05-15

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Five liquid Hg-In mixtures (Hg{sub 10}In{sub 90}, Hg{sub 30}In{sub 70}, Hg{sub 50}In{sub 50}, Hg{sub 70}In{sub 30} and Hg{sub 90}In{sub 10}) at 299K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and (l-In). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered alloys.

  15. Study of atomic structure of liquid Hg-In alloys using ab-initio molecular dynamics

    NASA Astrophysics Data System (ADS)

    Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

    2015-05-01

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Five liquid Hg-In mixtures (Hg10In90, Hg30In70, Hg50In50, Hg70In30 and Hg90In10) at 299K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and (l-In). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered alloys.

  16. 40 CFR 75.80 - General provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) shall retire or permanently discontinue use of the continuous emission monitoring system, any component... and: (i) A valid, quality-assured hour of Hg concentration data (in µgm/scm) has not been measured...

  17. In vivo formation and binding of SeHg complexes to the erythrocyte surface.

    PubMed

    Cherdwongcharoensuk, Duangrudee; Oliveira, Maria João; Aguas, Artur Perez

    2010-08-01

    The in vivo dynamics of selenium (Se) and mercury (Hg) interaction was studied in mouse tissues using direct visualization of individual Se, Hg, and SeHg particles on the surface of circulating erythrocytes. This high-resolution detection of Se and Hg was obtained by scanning electron microscopy coupled to X-ray microanalysis. BALB/c mice were injected in the peritoneal cavity with Se and Hg salts, and the animals were sacrificed 3 min after the Hg injection. Only a minority (9%) of the metal dots seen on mouse liver erythrocytes were SeHg complexes when Se and Hg salts were mixed together before injection. In contrast, the majority (73%) of metal dots on liver erythrocytes were SeHg complexes if Se was injected at least 5 min before Hg injection. All metal dots on liver erythrocytes were of SeHg complexes if Se was injected 9 or 12 min before the Hg injection. We conclude that the formation of stable in vivo SeHg complexes requires preliminary interaction of Se with a putative serum factor before complexes between Se and Hg are formed and are bound to the erythrocyte cell surface.

  18. Immobilization of Hg(II) by Coprecipitation in Sulfate-Cement Systems

    PubMed Central

    2012-01-01

    Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were identified by XRD as primary phases in Al systems, whereas gypsum and ferrihydrite were the main products in Hg–Fe precipitates. Characterization of Hg–Al solids by bulk Hg EXAFS, electron microprobe, and microfocused-XRF mapping indicated coordination of Hg by Cl ligands, multiple Hg and Cl backscattering atoms, and concentration of Hg as small particles. Thermodynamic predictions agreed with experimental observations for bulk phases, but Hg speciation indicated lack of equilibration with the final solution. Results suggest physical encapsulation of Hg as a polynuclear chloromercury(II) salt in ettringite as the primary immobilization mechanism. In Hg–Fe solids, structural characterization indicated Hg coordination by O atoms only and Fe backscattering atoms that is consistent with inner-sphere complexation of Hg(OH)20 coprecipitated with ferrihydrite. Precipitation of ferrihydrite removed Hg from solution, but the resulting solid was sufficiently hydrated to allow equilibration of sorbed Hg species with the aqueous solution. Electron microprobe XRF characterization of sorption samples with low Hg concentration reacted with cement and FeSO4 amendment indicated correlation of Hg and Fe, supporting the interpretation of Hg removal by precipitation of an Fe(III) oxide phase. PMID:22594782

  19. Mercury deposition and re-emission pathways in boreal forest soils investigated with Hg isotope signatures.

    PubMed

    Jiskra, Martin; Wiederhold, Jan G; Skyllberg, Ulf; Kronberg, Rose-Marie; Hajdas, Irka; Kretzschmar, Ruben

    2015-06-16

    Soils comprise the largest terrestrial mercury (Hg) pool in exchange with the atmosphere. To predict how anthropogenic emissions affect global Hg cycling and eventually human Hg exposure, it is crucial to understand Hg deposition and re-emission of legacy Hg from soils. However, assessing Hg deposition and re-emission pathways remains difficult because of an insufficient understanding of the governing processes. We measured Hg stable isotope signatures of radiocarbon-dated boreal forest soils and modeled atmospheric Hg deposition and re-emission pathways and fluxes using a combined source and process tracing approach. Our results suggest that Hg in the soils was dominantly derived from deposition of litter (∼90% on average). The remaining fraction was attributed to precipitation-derived Hg, which showed increasing contributions in older, deeper soil horizons (up to 27%) indicative of an accumulation over decades. We provide evidence for significant Hg re-emission from organic soil horizons most likely caused by nonphotochemical abiotic reduction by natural organic matter, a process previously not observed unambiguously in nature. Our data suggest that Histosols (peat soils), which exhibit at least seasonally water-saturated conditions, have re-emitted up to one-third of previously deposited Hg back to the atmosphere. Re-emission of legacy Hg following reduction by natural organic matter may therefore be an important pathway to be considered in global models, further supporting the need for a process-based assessment of land/atmosphere Hg exchange.

  20. OLIMPO: a balloon-borne, arcminute-resolution survey of the sky at mm and sub-mm wavelengths

    NASA Astrophysics Data System (ADS)

    Masi, S.; Ade, P.; Boscaleri, A.; de Bernardis, P.; de Petris, M.; de Troia, G.; Fabrini, M.; Iacoangeli, A.; Lamagna, L.; Lange, A.; Lubin, P.; Mauskopf, P.; Melchiorri, A.; Melchiorri, F.; Nati, L.; Nati, F.; Orlando, A.; Piacentini, F.; Pierre, M.; Pisano, G.; Polenta, G.; Rephaeli, Y.; Romeo, G.; Salvaterra, L.; Savini, G.; Valiante, E.; Yvon, D.

    2003-08-01

    We describe OLIMPO, a balloon-borne telescope devoted to cosmological and astrophysical surveys in the mm and sub-mm range. We summarize the relevant science (principally surveys of SZ clusters, of the sub-mm cosmic background and observations of galactic and cirrus dust) and the innovative sub-systems we have developed. The test flight of the telescope is planned for July 2004; the long duration flight is planned for the end of 2005.

  1. Public Library Subject Headings for 16mm Motion Pictures. Revised.

    ERIC Educational Resources Information Center

    California Library Association, Sacramento.

    Suggested subject headings for 16mm motion pictures are listed. The intent of the list is to provide audiovisual librarians with a tool which will aid them in making subject indexes for their printed catalogs. It is also intended as an authority for professional catalogers who may be called upon to catalog 16mm motion pictures. (Author/KKC)

  2. Growth kinetics of 1-2 mm and 3-4 mm colonies of Nostoc sphaeroides (Cyanophyta) in outdoor culture.

    PubMed

    Deng, Zhongyang; Yan, Chunlan; Lu, Fan; Hu, Qiang; Hu, Zhengyu

    2008-10-01

    Nostoc sphaeroides Kützing was cultivated in paddlewheel-driven raceway ponds and the growth kinetics of 1-2 mm and 3-4 mm colonies of N. sphaeroides was studied. The biomass productivities in 2.5 m(2) raceway ponds inoculated with 1-2 mm and 3-4 mm colonies were 5.2 and 0.25 g dry wt m(-2) d(-1), respectively. Furthermore, differently sized colonies showed different relative water content, total soluble carbohydrates, chlorophyll a content and density of filaments. This is the first report on mass culture of N. sphaeroides under outdoor conditions.

  3. MST-80B microcomputer trainer

    SciTech Connect

    Jones, G.D.; Fisher, E.R.; Spann, J.M.

    1980-04-01

    The microcomputer revolution in electronics is spreading so rapidly that it is difficult to educate enough people quickly and thoroughly in the new technology. Lawrence Livermore Laboratory's MST-80B was developed as a way to speed learning in in-house training courses, and it is now being widely used outside LLL. The MST-80B trainer is a complete, self-contained, microcomputer system housed in a briefcase. The trainer uses the Intel 8080A 8-Bit Microprocessor (CPU), and it has its own solid-state memory, a built-in keyboard, input and output ports, and a display for visual output. The trainer is furnished with a permanent Monitor Program (in Read-Only Memory) that allows users to enter, debug, modify, and run programs of their own easily. 8 figures, 3 tables.

  4. Frequency Measurements of Al+ and Hg+ Optical Standards

    NASA Astrophysics Data System (ADS)

    Itano, W. M.; Bergquist, J. C.; Rosenband, T.; Wineland, D. J.; Hume, D.; Chou, C.-W.; Jefferts, S. R.; Heavner, T. P.; Parker, T. E.; Diddams, S. A.; Fortier, T. M.

    2010-02-01

    Frequency standards based on narrow optical transitions in 27Al+ and 199Hg+ ions have been developed at NIST. Both standards have absolute reproducibilities of a few parts in 1017. This is about an order of magnitude better than the fractional uncertainty of the SI second, which is based on the 133Cs hyperfine frequency. Use of femtosecond laser frequency combs makes it possible to compare the optical frequency standards to microwave frequency standards or to each other. The ratio of the Al+ and Hg+ frequencies can be measured more accurately than the reproducibility of the primary cesium frequency standards. Frequency measurements made over time can be used to set limits on the time variation of fundamental constants, such as the fine structure constant α or the quark masses.

  5. A high-performance Hg(+) trapped ion frequency standard

    NASA Technical Reports Server (NTRS)

    Prestage, J. D.; Tjoelker, R. L.; Dick, G. J.; Maleki, L.

    1992-01-01

    A high-performance frequency standard based on (199)Hg(+) ions confined in a hybrid radio frequency (RF)/dc linear ion trap is demonstrated. This trap permits storage of large numbers of ions with reduced susceptibility to the second-order Doppler effect caused by the RF confining fields. A 160-mHz-wide atomic resonance line for the 40.5-GHz clock transition is used to steer the output of a 5-mHz crystal oscillator to obtain a stability of 2 x 10(exp -15) for 24,000-second averaging times. Measurements with a 37-mHz line width for the Hg(+) clock transition demonstrate that the inherent stability for this frequency standard is better than 1 x 10(exp -15) at 10,000-second averaging times.

  6. Measurement of linear stark interference in 199Hg.

    PubMed

    Loftus, T H; Swallows, M D; Griffith, W C; Romalis, M V; Heckel, B R; Fortson, E N

    2011-06-24

    We present measurements of Stark interference in the (61)S(0)→6(3)P(1) transition in (199)Hg, a process whereby a static electric field E mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to E-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, a(SI) = (a(M1) + a(E2)) = (5.8 ± 1.5) × 10(-9) (kV / cm)(-1), agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the (199)Hg EDM search apparatus to resolve nontrivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.

  7. Measurement of Linear Stark Interference in {sup 199}Hg

    SciTech Connect

    Loftus, T. H.; Swallows, M. D.; Griffith, W. C.; Romalis, M. V.; Heckel, B. R.; Fortson, E. N.

    2011-06-24

    We present measurements of Stark interference in the 6{sup 1}S{sub 0}{yields}6{sup 3}P{sub 1} transition in {sup 199}Hg, a process whereby a static electric field E mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to E-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, a{sub SI}=(a{sub M1}+a{sub E2})=(5.8{+-}1.5)x10{sup -9} (kV/cm){sup -1}, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the {sup 199}Hg EDM search apparatus to resolve nontrivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.

  8. Electrical Conductivity of HgTe at High Temperatures

    NASA Technical Reports Server (NTRS)

    Li, C.; Lehoczky, S. L.; Su, C.-H.; Scripa, R. N.

    2004-01-01

    The electrical conductivity of HgTe was measured using a rotating magnetic field method from 300 K to the melting point (943 K). A microscopic theory for electrical conduction was used to calculate the expected temperature dependence of the HgTe conductivity. A comparison between the measured and calculated conductivities was used to obtain the estimates of the temperature dependence of Gamma(sub 6)-Gamma(sub 8) energy gap from 300 K to 943 K. The estimated temperature coefficient for the energy gap was comparable to the previous results at lower temperatures (less than or equal to 300 K). A rapid increase in the conductivity just above 300 K and a subsequent decrease at 500 K is attributed to band crossover effects. This paper describes the experimental approach and some of the theoretical calculation details.

  9. Femtosecond laser-drilling-induced HgCdTe photodiodes.

    PubMed

    Zha, F-X; Li, M S; Shao, J; Yin, W T; Zhou, S M; Lu, X; Guo, Q T; Ye, Z H; Li, T X; Ma, H L; Zhang, B; Shen, X C

    2010-04-01

    Femtosecond-laser drilling may induce holes in HgCdTe with morphology similar to that induced by ion-milling in loophole technique. So-formed hole structures are proven to be pn junction diodes by the laser beam induced current characterization as well as the conductivity measurement. Transmission and photoluminescence spectral measurements on a n-type dominated hole-array structure give rise to different results from those of an ion-milled sample.

  10. HgCdTe Fabrication Using Directed Energy Techniques

    DTIC Science & Technology

    1982-04-01

    HgCdTE Pulsed electron beam processing Mercury Cadmium Teluride Hot wall epitaxy CdTe Heteroepitaxyj Cadmium Teluride Thin Films 20. ABSTRACT...control. Existing CdTe films show extensive twinning and poor surface morphology. Improvements are expected with a shift to sapphire substrates and the...Sample size is currently 0.5 inch square. These films were not twinned and had better surface morphology than the joriginal CdTe substrates. Good

  11. Monolithically integrated HgCdTe focal plane arrays

    NASA Astrophysics Data System (ADS)

    Velicu, Silviu; Lee, Tae-Seok; Ashokan, Renganathan; Grein, Christoph H.; Boieriu, Paul; Chen, Y. P.; Dinan, John H.; Lianos, Dimitrios

    2003-12-01

    The cost and performance of hybrid HgCdTe infrared focal plane arrays are constrained by the necessity of fabricating the detector arrays on a CdZnTe substrate. These substrates are expensive, fragile, are available only in small rectangular formats, and are not a good thermal expansion match to the silicon readout integrated circuit. We discuss in this paper an infrared sensor technology based on monolithically integrated infrared focal plane arrays that could replace the conventional hybrid focal plane array technology. We have investigated the critical issues related to the growth of HgCdTe on Si read-out integrated circuits and the fabrication of monolithic focal plane arrays: (1) the design of Si read-out integrated circuits and focal plane array layouts, (2) the low temperature cleaning of Si(001) wafers, (3) growth of CdTe and HgCdTe layers on read-out integrated circuits, (4) array fabrication, interconnection between focal plane array and read-out integrated circuit input nodes and demonstration of the photovoltaic operation, and (5) maintenance of the read-out integrated circuit characteristics after substrate cleaning, molecular beam epitaxy growth and device fabrication. Crystallographic, optical and electrical properties of the grown layers are presented. Electrical properties for diodes fabricated on misoriented Si and read-out integrated circuit substrates are discussed. The fabrication of arrays with demonstrated I-V properties show that monolithic integration of HgCdTe-based infrared focal plane arrays on Si read-out integrated circuits is feasible and could be implemented in the 3rd generation of infrared systems.

  12. HgCdTe Surface and Defect Study Program.

    DTIC Science & Technology

    1986-03-01

    LPE material. Solid state regrown (SSR) material and vertical Bridgman (VB) material exhibited lower background of most elements. The many isotopes...Sci. Technol. A 1 1735 (1983). 2. K. C. Mills, Thermodynamic Data for Inorganic Sulphides, Selenides and Tellurides (Betterworths, London, 1974). 3. A...34HgCdTe-SiO2 Interface Structure," 1983 U.S. Workshop on the Physics and Chemistry of Mercury Cadmium Telluride, February 8-10, 1983, Dallas, Texas. 5

  13. Fibre-optic bacterial biosensors and their application for the analysis of bioavailable Hg and As in soils and sediments from Aznalcollar mining area in Spain.

    PubMed

    Ivask, Angela; Green, Tal; Polyak, Boris; Mor, Amit; Kahru, Anne; Virta, Marko; Marks, Robert

    2007-02-15

    Fibre-optic biosensors for Hg and As were developed by attaching alginate-immobilised recombinant luminescent Hg- and As-sensor bacteria onto optical fibres. The optimised biosensors (consisting of seven layers of fibre-attached bacteria pre-grown till mid-logarithmic growth phase) enabled quantification of environmentally relevant concentrations of the target analytes: 2.6 microg l-1 of Hg(II) and 141 microg l-1 of As(V) or 18 microg l-1 of As(III). The highest viability and sensitivity for target analyte was obtained when fibre tips were stored in CaCl2 solution at -80 degrees C. Applicability of the fibre-optic biosensors in parallel to the respective non-immobilised sensors was assessed on 10 natural soil and sediment samples from Aznalcollar mining area (Spain). On the average 0.2% of the total Hg and 0.87% of the total As proved bioavailable to fibre-attached bacteria. Interestingly, about 20-fold more Hg and 4-fold more As was available to non-immobilised sensor bacteria indicating the importance of direct cell contact (possible only for non-immobilised cells) for enhanced bioavailability of these metals in solid samples.

  14. Growth of {alpha}-HgI{sub 2} single crystals from physical vapor transport in an oil-bath furnace

    SciTech Connect

    Zhou Hantang; Lee, C.-H.; Chung Jiaming; Shin, C.-T.; Chiu, K.-C.; Lan, S.-M

    2003-12-10

    The growth of {alpha}-HgI{sub 2} crystals from physical vapor transport in a closed ampoule immerged in a simple and economical oil-bath furnace with an external heating coil imposed is discussed. The temperatures of the source side, T{sub sou}, of the maximum value, T{sub max}, and of the crystal growth side, T{sub cry}, together with dT/dx are changed for different growth conditions. The physical properties of the as-grown {alpha}-HgI{sub 2} crystals are characterized by scanning electron microscopy, X-ray diffraction, and I-V measurements with respect to different growth conditions. It is found that the {alpha}-HgI{sub 2} crystals grown from T{sub sou}=125 deg. C, T{sub max}=135 deg. C, T{sub cry}=114 deg. C, dT/dx=2.6 deg. C/mm, and with 5 Torr inert gas inside the growth ampoule exhibit the best qualities, such as, observable facets, transparent red color, and a low density of defects and grain boundaries.

  15. Cationic coordination compound Cs2Hg3I8 for IR NLO material: Synthesis, crystal growth and characterizations

    NASA Astrophysics Data System (ADS)

    Sathiskumar, S.; Kathiravan, P.; Balakrishnan, T.

    2015-06-01

    Single crystals Cs2Hg3I8 of dimensions 5 × 3 × 4 mm3 were grown by solution growth method at room temperature and structurally characterized by single crystal X - ray diffraction. Cs2Hg3I8 compound crystallizes in a noncentrosymmetric space group Cm with the crystal data of a = 7.4415 Å, b = 21.6629 Å, c = 7.6726 Å, α, β = 90°, γ = 108.05° and Z = 2. The grown crystals were characterized by powder X - ray diffraction analysis and the various diffraction planes are indexed. The presence of functional groups was identified qualitatively by Fourier transform infrared and FT - Raman spectral analyses. Ultraviolet - visible spectral analyses shows that the crystal has low UV cut off at 388 nm combined with very good transparency of 98 % in a wide range. The optical band gap was estimated to be 3 eV. Mechanical hardness of the grown crystal Cs2Hg3I8 was determined. The dielectric response of the crystal with varying frequencies was studied. Differential scanning calorimetry (DSC) analysis shows that the grown crystal has very good thermal stability up to 97.5°C.

  16. EDTA and urease effects on Hg accumulation by Lepidium sativum.

    PubMed

    Smolińska, Beata; Cedzyńska, Krystyna

    2007-11-01

    The phytoextraction process was conducted under laboratory conditions with the use of garden cress plants (Lepidium sativum). The experiment was carried out in a model soil, which was characterized before conducting the process. Inorganic forms of mercury (HgCl(2), HgSO(4), Hg(NO(3))(2)) were used for contamination of the soil. The phytoextraction process was conducted after EDTA application to the soil and after urease application. Also the influence of simultaneous addition of ethylenediaminetetraacetic acid (EDTA) and urease into the soil on phytoextraction process was measured. In all variants of phytoextraction process the total mercury concentrations in roots, stems and leaves of garden cress were determined. The result showed that garden cress accumulated mercury from soil. The overall maximum concentration of mercury in its compounds was found in roots of the plant. In all cases, before addition of urease and EDTA, the translocation process and distribution of mercury in the plant tissues were limited. The addition of urease caused an increase of enzyme activity in the soil and at the same time caused an increase of mercury concentration in plant tissues. Application of EDTA increased solubility of mercury and caused an increase of metal accumulation by plants. After simultaneous addition of EDTA and urease into the soil garden cress accumulated about 20% of total mercury concentration in the soil. Most of mercury compounds were accumulated in leaves and stems of the plants (46.0-56.9% of total mercury concentration in the plant tissues).

  17. Collective and quasiparticle excitations in superdeformed {sup 190}Hg

    SciTech Connect

    Wilson, A.N.; Timar, J.; Sharpey-Schafer, J.F.; Crowell, B.; Carpenter, M.P.; Janssens, R.V.; Blumenthal, D.J.; Ahmad, I.; Astier, A.; Azaiez, F.; Bergstroem, M.; Ducroux, L.; Gall, B.J.; Hannachi, F.; Khoo, T.L.; Korichi, A.; Lauritsen, T.; Lopez-Martens, A.; Meyer, M.; Nisius, D.; Paul, E.S.; Porquet, M.G.; Redon, N.; Wilson, J.N.; Nakatsukasa, T. ||||||

    1996-08-01

    Superdeformed (SD) states of {sup 190}Hg have been studied with the Eurogam Phase 2 {gamma}-ray spectrometer using the {sup 160}Gd({sup 34}S,4{ital n}) reaction. Two new excited SD bands have been found and identified as belonging to this nucleus, bringing the total number of SD bands in {sup 190}Hg to 4. One of the new bands has a dynamic moment of inertia that is very similar to that of the yrast SD band of {sup 190}Hg and most other SD bands in the {ital A}{approximately}190 region. In contrast, the other band has a dynamic moment of inertia which is mainly constant as a function of rotational frequency and exhibits a dramatic increase at the lowest frequencies. The observed dynamic moments of inertia are compared with the results of random phase approximation calculations based on the cranked shell model. Finally, the known excited SD band has been extended towards lower frequencies and new transitions have been found linking this band to the yrast SD band. The extracted {ital B}({ital E}1) values of the new linking transitions give further support for the possible octupole vibrational character of this band. {copyright} {ital 1996 The American Physical Society.}

  18. Collective and quasiparticle excitations in superformed Hg-190.

    SciTech Connect

    Wilson, A. N.; Timar, J.; Sharpey-Schafer, J. F.; Crowell, B.; Carpenter, M. P.; Janssens, R. V. F.; Blumenthal, D. J.; Ahmad, I.; Astier, A.; Azaiez, F.; Bergstrom, M.; Ducroux, L.; Gall, B. J. P.; Hannachi, F.; Khoo, T. L.; Korichi, A.; Lauritsen, T.; Lopez-Martens, A.; Meyer, M.; Nisius, D.; Paul, E. S.; Porquet, M. G.; Redon, N.; Wilson, J. N.; Nakatsukasa, T.; Physics; Univ. of Liverpool; Univ. of Liverpool; Centre de Recherches Nucleaires; Inst. de Physique Nucleaire Lyon; I.P.N.; Inst. of Physique Nucleaire Lyon; C.S.N.S.M.; AECL

    1996-08-01

    Superdeformed (SD) states of {sup 190}Hg have been studied with the Eurogam Phase 2 {gamma}-ray spectrometer using the {sup 160}Gd({sup 34}S,4n) reaction. Two new excited SD bands have been found and identified as belonging to this nucleus, bringing the total number of SD bands in {sup 190}Hg to 4. One of the new bands has a dynamic moment of inertia that is very similar to that of the yrast SD band of {sup 190}Hg and most other SD bands in the A{approx}190 region. In contrast, the other band has a dynamic moment of inertia which is mainly constant as a function of rotational frequency and exhibits a dramatic increase at the lowest frequencies. The observed dynamic moments of inertia are compared with the results of random phase approximation calculations based on the cranked shell model. Finally, the known excited SD band has been extended towards lower frequencies and new transitions have been found linking this band to the yrast SD band. The extracted B(E1) values of the new linking transitions give further support for the possible octupole vibrational character of this band.

  19. Massless Dirac fermions in semimetal HgCdTe

    NASA Astrophysics Data System (ADS)

    Marchewka, M.; Grendysa, J.; Żak, D.; Tomaka, G.; Śliż, P.; Sheregii, E. M.

    2017-01-01

    Magneto-transport results obtained for the strained 100 nm thick Hg1-x CdxTe (x=0.135) layer grown by MBE on the CdTe/GaAs substrate are interpreted by the 8×8 kp model with the in-plane tensile strain. The dispersion relation for the investigated structure proves that the Dirac point is located in the gap caused by the strain. It is also shown that the fan of the Landau Levels (LL's) energy calculated for topological protected surface states for the studied HgCdTe alloy corresponds to the fan of the LL's calculated using the graphen-like Hamiltonian which gives excellent agreement with the experimental data for velocity on the Fermi level equal to vf ≈ 0.85×106 m/s. That characterized strained Hg1-x CdxTe layers (0.13 < x < 0.14) are a perfect Topological Insulator with good perspectives of further applications.

  20. HgCdTe APDs for free space optical communications

    NASA Astrophysics Data System (ADS)

    Rothman, J.; Lasfargues, G.; Abergel, J.

    2015-10-01

    HgCdTe avalanche photodiode single element detectors have been developed for a large scope of photon starved applications. The present communication is dedicated to use of these detectors for free space optical communications. In this perspective we present and discuss the sensitivity and bandwidth that has been measured directly on HgCdTe APDs and on detector modules. In particular, we report on the performance of TEC cooled large area detectors with sensitive diameters ranging from 30- 200 μm, characterised by detector gains of 2- 20 V/μW and noise equivalent input power of 0.1-1 nW for bandwidths ranging from 20 to 400 MHz. One of these detectors has been used during the lunar laser communication demonstration (LLCD) and the results The perspectives for high data rate transmission is estimated from the results of impulse response measurements on HgCdTe APDs. These results indicate that bandwidths close to 10 GHz can be achieved in these devices. The associated sensitivity at an APD gain of 100 is estimated to be below 4 photons rms (NEP<10 nW) for APDs operated at 300 K.

  1. Amplitude modulation drive to rectangular-plate linear ultrasonic motors with vibrators dimensions 8 mm x 2.16 mm X 1 mm.

    PubMed

    Ming, Yang; Hanson, Ben; Levesley, Martin C; Walker, Peter G; Watterson, Kevin G

    2006-12-01

    In this paper, to exploit the contribution from not only the stators but also from other parts of miniature ultrasonic motors, an amplitude modulation drive is proposed to drive a miniature linear ultrasonic motor consisting of two rectangular piezoelectric ceramic plates. Using finite-element software, the first longitudinal and second lateral-bending frequencies of the vibrator are shown to be very close when its dimensions are 8 mm x 2.16 mm x 1 mm. So one single frequency power should be able to drive the motor. However, in practice the motor is found to be hard to move with a single frequency power because of its small vibration amplitudes and big frequency difference between its longitudinal and bending resonance, which is induced by the boundary condition variation. To drive the motor effectively, an amplitude modulation drive is used by superimposing two signals with nearly the same frequencies, around the resonant frequency of the vibrators of the linear motor. When the amplitude modulation frequency is close to the resonant frequency of the vibrator's surroundings, experimental results show that the linear motor can move back and forward with a maximum thrust force (over 0.016 N) and a maximum velocity (over 50 mm/s).

  2. Chemical effects on the L i( i=1-3) sub-shell X-ray relative intensities for some compounds of Hg

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Puri, Sanjiv

    2011-11-01

    The intensity ratios, IL k/ IL α(exp) ( k= l, η, β4,6, β1,2,3,15, β5,7, γ1,5, γ2,3,6,8, γ4, β, γ), have been measured for some compounds of 80Hg, namely, HgI 2, Hg(C 2H 3O 2) 2 and a pure 80Hg target (liquid form) at 22.6 keV incident photon energy in order to investigate the influence of chemical effects on these ratios for a heavy transition element. The measurements have been performed using the EDXRF spectrometer involving a disk type radioactive source of Cd 109 and a Peltier cooled Si-PIN X-ray detector arranged in the 90° reflection geometry. The measured intensity ratios have been compared with the theoretical IL k/ IL α (Thr.) values ( Kumar et al., 2010) and those calculated using the fluorescence and Coster-Kronig yields tabulated by Campbell (2003, 2009) and Krause (1979) in order to check the reliability of these available values. The measured ratios, IL β5,7 / IL α (Exp.), were found to be influenced by the chemical effects.

  3. Japanese Science Films; a Descriptive and Evaluative Catalog of: 16mm Motion Pictures, 8mm Cartridges, and Video Tapes.

    ERIC Educational Resources Information Center

    Newren, Edward F., Ed.

    One hundred and eighty Japanese 16mm motion pictures, 8mm cartridges, and video tapes produced and judged appropriate for a variety of audience levels are listed in alphabetical order by title with descriptive and evaluative information. A subject heading list and a subject index to the film titles are included, as well as a sample of the…

  4. Assessment of Hg Pollution Released from a WWII Submarine Wreck (U-864) by Hg Isotopic Analysis of Sediments and Cancer pagurus Tissues.

    PubMed

    Rua-Ibarz, Ana; Bolea-Fernandez, Eduardo; Maage, Amund; Frantzen, Sylvia; Valdersnes, Stig; Vanhaecke, Frank

    2016-10-04

    Hg pollution released from the U-864 submarine sunk during WWII and potential introduction of that Hg into the marine food chain have been studied by a combination of quantitative Hg and MeHg determination and Hg isotopic analysis via cold vapor generation multicollector inductively coupled plasma-mass spectrometry (CVG-MC-ICP-MS) in sediment and Cancer pagurus samples. The sediment pollution could be unequivocally linked with the metallic Hg present in the wreck. Crabs were collected at the wreck location and 4 nmi north and south, and their brown and claw meat were analyzed separately. For brown meat, the δ(202)Hg values of the individuals from the wreck location were shifted toward the isotopic signature of the sediment and, thus, the submarine Hg. Such differences were not found for claw meat. The isotope ratio results suggest direct ingestion of metallic Hg by C. pagurus but do not offer any proof for any other introduction of the submarine Hg into the marine food chain.

  5. Selective Hg(II) adsorption from aqueous solutions of Hg(II) and Pb(II) by hydrolyzed acrylamide-grafted PET films.

    PubMed

    Rahman, Nazia; Sato, Nobuhiro; Sugiyama, Masaaki; Hidaka, Yoshiki; Okabe, Hirotaka; Hara, Kazuhiro

    2014-01-01

    Selective Hg(II) adsorption from aqueous solutions of Hg(II) and Pb(II) using hydrolyzed acrylamide (AAm)-grafted polyethylene terephthalate (PET) films was examined to explore the potential reuse of waste PET materials. Selective recovery of Hg(II) from a mixture of soft acids with similar structure, such as Hg(II) and Pb(II), is important to allow the reuse of recovered Hg(II). An adsorbent for selective Hg(II) adsorption was prepared by γ-ray-induced grafting of AAm onto PET films followed by partial hydrolysis through KOH treatment. The adsorption capacity of the AAm-grafted PET films for Hg(II) ions increased from 15 to 70 mg/g after partial hydrolysis because of the reduction of hydrogen bonding between -CONH2 groups and the corresponding improved access of metal ions to the amide groups. The prepared adsorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The absorbent film showed high selectivity for the adsorption of Hg(II) over Pb(II) throughout the entire initial metal concentration range (100-500 mg/L) and pH range (2.2-5.6) studied. The high selectivity is attributed to the ability of Hg(II) ions to form covalent bonds with the amide groups. The calculated selectivity coefficient for the adsorbent binding Hg(II) over Pb(II) was 19.2 at pH 4.5 with an initial metal concentration of 100 mg/L. Selective Hg(II) adsorption equilibrium data followed the Langmuir model and kinetic data were well fitted by a pseudo-second-order equation. The adsorbed Hg(II) and Pb(II) ions were effectively desorbed from the adsorbent film by acid treatment, and the regenerated film showed no marked loss of adsorption capacity upon reuse for selective Hg(II) adsorption.

  6. Unusual speciation and retention of Hg at a coal-fired power plant.

    PubMed

    Córdoba, Patricia; Maroto-Valer, M; Ayora, Carlos; Perry, Ron; Rallo, Manuela; Font, Oriol; Izquierdo, Maria; Querol, Xavier

    2012-07-17

    An unusual and different speciation of Hg in the outgoing gaseous stream of the flue gas desulfurization (OUT-FGD) system was revealed at two Spanish power plants (PP1 and PP2) equipped with a forced oxidation wet FGD system with water recirculation to the scrubber. At PP1 and PP2, a high proportion of Hg escapes from the electrostatic precipitator in gaseous form, Hg(2+) (75-86%) being the species that enters the FGD. At PP1 Hg(0) (71%) was the prevalent Hg OUT-FGD species, whereas at PP2 Hg(2+) was the prevalent Hg OUT-FGD species in 2007 (66%) and 2008 (87%). The unusual speciation of gaseous Hg OUT-FGD and the different Hg retentions between 2007 and 2008 at PP2 were attributable to the evaporation of HgCl(2) particles from the aqueous phase of gypsum slurry in the OUT-FGD gas and the Al additive used at PP2, respectively. The Al additive induced the retention of Hg as HgS in the 2007 FGD gypsum, thus reducing gaseous emissions of Hg in the OUT-FGD gas.

  7. Maternal-fetal distribution of mercury ( sup 203 Hg) released from dental amalgam fillings

    SciTech Connect

    Vimy, M.J.; Takahashi, Y.; Lorscheider, F.L. )

    1990-04-01

    In humans, the continuous release of Hg vapor from dental amalgam tooth restorations is markedly increased for prolonged periods after chewing. The present study establishes a time-course distribution for amalgam Hg in body tissues of adult and fetal sheep. Under general anesthesia, five pregnant ewes had twelve occlusal amalgam fillings containing radioactive 203Hg placed in teeth at 112 days gestation. Blood, amniotic fluid, feces, and urine specimens were collected at 1- to 3-day intervals for 16 days. From days 16-140 after amalgam placement (16-41 days for fetal lambs), tissue specimens were analyzed for radioactivity, and total Hg concentrations were calculated. Results demonstrate that Hg from dental amalgam will appear in maternal and fetal blood and amniotic fluid within 2 days after placement of amalgam tooth restorations. Excretion of some of this Hg will also commence within 2 days. All tissues examined displayed Hg accumulation. Highest concentrations of Hg from amalgam in the adult occurred in kidney and liver, whereas in the fetus the highest amalgam Hg concentrations appeared in liver and pituitary gland. The placenta progressively concentrated Hg as gestation advanced to term, and milk concentration of amalgam Hg postpartum provides a potential source of Hg exposure to the newborn. It is concluded that accumulation of amalgam Hg progresses in maternal and fetal tissues to a steady state with advancing gestation and is maintained. Dental amalgam usage as a tooth restorative material in pregnant women and children should be reconsidered.

  8. Just passing through --- high Hg deposition to Puerto Rico forest moves quickly off the landscape

    NASA Astrophysics Data System (ADS)

    Shanley, J. B.; Willenbring, J. K.; Kaste, J. M.; Occhi, M.; McDowell, W. H.

    2012-12-01

    Atmospheric mercury (Hg) in wet deposition at the Luquillo Experimental Forest in northeastern Puerto Rico, averages 28 μg m-2 yr-1, higher than any site in the USA Mercury Deposition Network. Despite the high deposition, Hg content of soils, vegetation, and biota are below global averages. The low Hg content of watershed surfaces, coupled with exceptionally high stream total Hg flux, suggest that most of the Hg passes through the watershed with minimal retention. We assessed Hg dynamics in two adjacent watersheds, Rio Icacos underlain by quartz diorite, and Rio Mameyes underlain by volcaniclastic rocks. At both sites, high-flow Hg concentrations approached 100 ng L-1, dominated by particulate Hg. In order to assess the apparent pass-through nature of Hg in this tropical forest, we measured 7Be and 10Be isotopes from natural, cosmogenic fallout adsorbed on stream suspended particles to constrain the Hg age /residence time and source (atmospheric vs. geogenic or legacy Hg from 19th century gold mining). Ubiquitous 7Be (half-life 53 days) and relatively high 7Be/10Be ratios on suspended particles suggest that stream Hg was dominated by erosion from exposed surfaces, supporting a short residence time. The low watershed retention of the high Hg throughput limits adverse biological effects in this tropical ecosystem.

  9. Studies on efficiency of guava (Psidium guajava) bark as bioadsorbent for removal of Hg (II) from aqueous solutions.

    PubMed

    Lohani, Minaxi B; Singh, Amarika; Rupainwar, D C; Dhar, D N

    2008-11-30

    Biosorption of Hg (II) was investigated in this study by using guava bark powder (GBP). In the batch system, effects of various parameters like contact time, initial concentration, pH and temperature were investigated. Removal of Hg (II) was pH dependent and was found maximum at pH 9.0. Based on this study, the thermodynamic parameters like change in standard Gibb's free energy (DeltaG(0)), standard enthalpy (DeltaH(0)) and standard entropy (DeltaS(0)) were evaluated. The rate kinetic study was found to follow second-order. The applicability of Freundlich adsorption isotherm model was tested. The value of regression coefficient was greater than 0.99. This indicated that the isotherm model adequately described the experimental data of the biosorption of Hg (II). Maximum adsorption of 3.364 mgg(-1) was reached at 80 min. The results of the study showed that guava bark powder can be efficiently used as a low-cost alternative for the removal of divalent mercury from aqueous solutions.

  10. The 19 mm data recorders similarities and differences

    NASA Technical Reports Server (NTRS)

    Atkinson, Steve

    1992-01-01

    Confusion over the use of non-video 19 mm data recorders is becoming more pronounced as we enter the world of high performance computing. This paper addresses the following: the differences between ID-1, ID-2, MIL-STD-2179 and DD-2; what the proper machine is for various applications; how the machine can be integrated into an environment; and any misconceptions there might be about 19 mm tape recorders. DD-2 and 19 mm instrumentation recorders have missions for which each is well designed. While the differences may appear subtle, understanding the difference between the two is the key to picking the right recorder for a particular application.

  11. 120MM Mortar MIL-STD-1660 Tests

    DTIC Science & Technology

    1994-07-01

    AD-A285 065 FINAL REPORT JULY 1994 REPORT NO. 91-18 120MM MORTAR MIL- STD - 1660 TESTS 94-309 󈧷 Prepared for: Dist.iviiior Unlimited I I U.S. Army...Inidude Securt Ciassificz ion) 120MM Mortar MIL- STD - i660 Tests 12- PERSONAL AUTHOR IS) William R. Meyer ~13a. TYPE OF REPORT 13b. TINE COVERED 14...Armnament Re- earch, Development and Engineering Center (ARDEC), SMCAR-AEP, to conduct MIL- STD - 1660 tests on 120M,\\M mortar rounds on wooden p~allets

  12. Growth of 450 mm diameter semiconductor grade silicon crystals

    NASA Astrophysics Data System (ADS)

    Lu, Zheng; Kimbel, Steven

    2011-03-01

    Research and development of the next generation 450 mm semiconductor grade silicon crystal and related technology have been carried out in MEMC following the company's philosophy to stay one generation ahead on research and development. The first 450 mm dislocation free crystal was grown in early 2009 and the first 450 mm semiconductor wafer was produced shortly after. General challenges in crystal growth process, puller, and hot zone designs, as well as control, automation, and handling are discussed in this paper. General considerations on working with customers and equipment manufacturers on fundamental crystal and wafer quality characteristics are also discussed.

  13. Experimental evidence for the third level (А+) of Hg vacancy in Hg1-xCdxTe

    NASA Astrophysics Data System (ADS)

    Shepelskii, G. A.; Strikha, M. V.; Gassan-zade, S. G.

    2012-11-01

    Mercury vacancy in Hg1-xCdxTe is not a two-level (as it was supposed until now), but a three-level acceptor. A third, most shallow (1-1.5 meV) level (А+ state) appears due to a capture of a third hole by a neutral acceptor, after the two deeper vacancy levels (A- and А0 states) are already occupied by holes. Due to a capture of nonequilibrium holes by neutral mercury vacancies (under radiation) a positive space charge region arises near an irradiated surface. This causes the anomalies of photoelectromagnetic effect, observed in р-Hg1-xCdxTe at T < 10-12 K.

  14. Phase diagrams and microscopic structures of (Hg,Cd)Te, (Hg,Zn)Te, and (Cd,Zn)Te alloys

    NASA Technical Reports Server (NTRS)

    Patrick, R. S.; Chen, A.-B.; Sher, A.; Berding, M. A.

    1988-01-01

    A cluster theory based on the quasi-chemical approximation has been applied to study the local correlation bond-length distribution, and phase diagrams of the II-VI pseudobinary alloys Hg(1 - x)Cd(x)Te, Hg(1 - x)Zn(x)Te, and Cd(1 - x)Zn(x)Te. The cluster energy is calculated by letting it relax in some effective alloy medium and then considering the contributions from the strain and chemical energies. Two different models are presented to simulate the alloy medium. While both models show that all three alloys have nearly random distributions, the signs of the local correlation prove to be sensitive to the alloy medium chosen for the energy calculation. Good agreement is found between experiment and the bond lengths and phase diagrams in both models.

  15. Advanced Applications Flight Equipment (AAFE) 125mm ultraviolet spectrometer

    NASA Technical Reports Server (NTRS)

    Schroeder, R. J.

    1973-01-01

    The conceptual work is reported for the 125 mm ultraviolet spectrometer to measure atmospheric ozone as a function of height, latitude, and time. The instrument is described along with the assembly, test, and calibration.

  16. Building 931, oblique view to southeast, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 931, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  17. Building 904, oblique view to southeast, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  18. Building 1204, oblique view to west, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 1204, oblique view to west, 135 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  19. Building 909, oblique view to southeast, 135 mm lens. Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 909, oblique view to southeast, 135 mm lens. Building 908 at extreme right for context. - Travis Air Force Base, Handling Crew Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  20. Building 1204, oblique view to east, 90 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 1204, oblique view to east, 90 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  1. Building 904, oblique view to northeast, 210mm lens Travis ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to northeast, 210mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  2. Building 932, oblique view to northwest, 90 mm lens. Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 932, oblique view to northwest, 90 mm lens. Building 933-935 at extreme left. - Travis Air Force Base, Nuclear Weapons Assembly Plant 5, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  3. Building 931, oblique view to northwest, 210 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 931, oblique view to northwest, 210 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  4. Building 904, oblique view to northwest, 135 mm lens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to northwest, 135 mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  5. QM/MM methods for studying enzymatic reactions of glycosyltransferases.

    PubMed

    Tvaroška, Igor

    2015-01-01

    Hybrid quantum mechanics and molecular mechanics (QM/MM) methods have become a powerful tool to provide an accurate and effective description of complex biological systems. The QM treatment of the electronic structure of an active site region and the rest of the enzyme by molecular mechanics allows enzymatic reaction to being modeled with including the impact of environment. Different reaction pathways of the enzymatic mechanism can be tested--transition states (TS) and intermediates characterized using QM/MM methods, leading to significant advances in understanding enzymatic reactions. This chapter discusses the ideas and the setting up of the structural and computational models for calculations with QM/MM software. The use of QM/MM methodology is also illustrated using the case of the inverting glycosyltransferase GnT-I.

  6. On-line method of determining utilization factor in Hg-196 photochemical separation process

    DOEpatents

    Grossman, Mark W.; Moskowitz, Philip E.

    1992-01-01

    The present invention is directed to a method for determining the utilization factor [U] in a photochemical mercury enrichment process (.sup.196 Hg) by measuring relative .sup.196 Hg densities using absorption spectroscopy.

  7. Ab-initio molecular dynamics simulations of liquid Hg-Pb alloys

    NASA Astrophysics Data System (ADS)

    Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

    2014-04-01

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-Pb alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-Pb mixtures (Hg30Pb70, Hg50Pb50 and Hg90Pb10) at 600K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and lead (l-Pb). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered three alloys. Among the all considered alloys, Hg50Pb50 alloy shows presence of more chemical ordering and presence of hetero-coordination.

  8. High- and Mid-temperature Superconducting Sensors for Far IR/Sub-mm Applications in Space

    NASA Technical Reports Server (NTRS)

    Lakew, Brook; Brasunas, J. C.

    2004-01-01

    In this review paper an overview of the potential applications of high Tc (approx. 90 K) superconductors (HTS) and mid-Tc (approx. 39 K) superconductors (MTS) thin films in far IR/Sub-mm thermal detectors is presented. HTSs (YBCO, GdBCO etc.) were discovered in the late 80s while superconductivity in MgB2, an MTS, was discovered in 2001. The sharp transition in transport properties of HTS has allowed the fabrication of composite infrared thermal detectors (bolometers) with better figures of merit than thermopile detectors - thermopiles are currently on board the CIRS instrument on the Cassini mission to Saturn. The potential for developing even more sensitive sensors for IR/Sub-mm applications using MgB2 thin films is assessed. Current MgB2 thin film deposition techniques and film quality are reviewed.

  9. The 19 mm date recorders: Similarities and differences

    NASA Technical Reports Server (NTRS)

    Atkinson, Steve

    1991-01-01

    Confusion over the use of non-video 19 mm data recorders is becoming more pronounced in the world of high performance computing. The following issues are addressed: (1) the difference between ID-1, ID-2, MIL-STD-2179, and DD-2; (2) the proper machine for the necessary application; and (3) integrating the machine into an existing environment. Also, an attempt is made to clear up any misconceptions there might be about 19 mm tape recorders.

  10. [Degradation of oil derivatives by Acinetobacter calcoaceticus MM5].

    PubMed

    Marín, M M; Ortiz, M L; Laborda, F

    1994-01-01

    This paper describes the isolation of microorganisms from polluted heating oil. The growth of one of them has been studied (Acinetobacter calcoaceticus MM5) in several linear and branched hydrocarbons as well as the effect of its growth on commercial diesel oil. Acinetobacter calcoaceticus MM5 is not capable of using glucose as its only source of carbon, and it needs the presence of nitrogen and phosphorus sources to degrade any petroleum by-product.

  11. QM/MM free energy simulations: recent progress and challenges.

    PubMed

    Lu, Xiya; Fang, Dong; Ito, Shingo; Okamoto, Yuko; Ovchinnikov, Victor; Cui, Qiang

    Due to the higher computational cost relative to pure molecular mechanical (MM) simulations, hybrid quantum mechanical/molecular mechanical (QM/MM) free energy simulations particularly require a careful consideration of balancing computational cost and accuracy. Here we review several recent developments in free energy methods most relevant to QM/MM simulations and discuss several topics motivated by these developments using simple but informative examples that involve processes in water. For chemical reactions, we highlight the value of invoking enhanced sampling technique (e.g., replica-exchange) in umbrella sampling calculations and the value of including collective environmental variables (e.g., hydration level) in metadynamics simulations; we also illustrate the sensitivity of string calculations, especially free energy along the path, to various parameters in the computation. Alchemical free energy simulations with a specific thermodynamic cycle are used to probe the effect of including the first solvation shell into the QM region when computing solvation free energies. For cases where high-level QM/MM potential functions are needed, we analyze two different approaches: the QM/MM-MFEP method of Yang and co-workers and perturbative correction to low-level QM/MM free energy results. For the examples analyzed here, both approaches seem productive although care needs to be exercised when analyzing the perturbative corrections.

  12. HgCdTe e-APD detector arrays with single photon sensitivity for space lidar applications

    NASA Astrophysics Data System (ADS)

    Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.

    2014-05-01

    A multi-element HgCdTe electron initiated avalanche photodiode (e-APD) array has been developed for space lidar. The detector array was fabricated with 4.3μm cutoff HgCdTe with a spectral response from 0.4 to 4.3 μm. We have demonstrated a 4x4 e-APD array with 80 μm square elements followed by a custom cryogenic CMOS read-out integrated circuit (ROIC). The device operates at 77K inside a small closed-cycle cooler-Dewar with the support electronics integrated in a field programmable gate array. Measurements showed a unity gain quantum efficiency of about 90% at 1.5-1.6 μm wavelength. The bulk dark current of the HgCdTe e-APD at 77K was less than 50,000 input referred electrons/s at 12 V APD bias where the APD gain was 620 and the measured noise equivalent power (NEP) was 0.4 fW/Hz1/2. The electrical bandwidth of the device was about 6 MHz, mostly limited by the ROIC, but sufficient for the lidar application. Although the devices were designed for low bandwidth pulse detections, the high gain and low dark current enabled them to be used for single photon detections. Because the APD was biased below the break-down voltage, the output is linear to the input signal and there were no nonlinear effect such as dead-time and afterpulsing, and no need for gated operation. A new series of HgCdTe e-APDs have also been developed with a much wider bandwidth ROIC and higher APD gain, which is expected to give a much better performance in single photon detections.

  13. A 40+ year record of Cd, Hg, Pb, and U deposition in sediments of Patroon Reservoir, Albany County, NY, USA.

    PubMed

    Arnason, John G; Fletcher, Barbara A

    2003-01-01

    Sediments of the Patroon Creek watershed (33 km(2)) are known to contain significant concentrations of heavy metals derived from two industrial sites within the watershed. Mercury Refining, Inc (Mereco) has stored and recycled Hg from 1955 to the present day, and National Lead Industries (NLI) manufactured aircraft components containing Cd, Pb, and U from 1958 to 1984. Here we present the first record of heavy metal deposition as preserved in a 3-m long sediment core collected in 1999 from Patroon Reservoir, a small water body (1.3 ha) downstream of the industrial sites. Bulk sediment samples were collected from the core at 0.05-m intervals and analyzed for total Cd, Pb, and U by ICP-MS and total Hg by CVAAS. Total Hg increases from less than 1 mg kg(-1) (dw) below 1.68 m, to a maximum of 6.2 mg kg(-1) at 0.80 m, and then declines to the sediment-water interface. Total Cd, Pb, and U concentrations increase abruptly above 1.68 m to maximum values of 25, 320, and 3600 mg kg(-1) (dw), respectively, and then decline gradually upwards. By correlating metal profiles with industrial history, we conclude that the 1.68 m horizon was deposited no earlier than 1958, the beginning of aircraft component manufacturing at NLI. The average, apparent sedimentation rate within the reservoir has a minimum value of approximately 0.04 m year(-1) for the 41-year period from 1958 to 1999. In the interval 0--1.68 m, average concentrations of Cd, Hg, Pb, and U are 1.69, 1.50, 461, and 13 mg kg(-1), respectively. These levels are comparable with other lake, reservoir and stream sediments that have been moderately to severely impacted by industrial pollution and are above levels expected to be detrimental to aquatic organisms.

  14. Sensitive naked-eye detection of Hg2+ based on the aggregation and filtration of thymine functionalized vesicles caused by selective interaction between thymine and Hg2+.

    PubMed

    Ma, Xue; Sheng, Zhonghan; Jiang, Long

    2014-07-07

    We report a sensitive, selective and low-cost method for the naked-eye detection of Hg(2+). The principle is based on rapid interaction between functionalized PDA vesicles and Hg(2+), which leads to obvious aggregation of vesicles. Furthermore, using only a simple filtration process, without using any other color indicator or specialized equipment, a higher detection sensitivity for Hg(2+) (0.1 μM) than chromophoric colorimetric sensors (approximately 1-100 μM) was obtained.

  15. Impacts of forest harvesting on mobilization of Hg and MeHg in drained peatland forests on black schist or felsic bedrock.

    PubMed

    Ukonmaanaho, Liisa; Starr, Mike; Kantola, Marjatta; Laurén, Ari; Piispanen, Juha; Pietilä, Heidi; Perämäki, Paavo; Merilä, Päivi; Fritze, Hannu; Tuomivirta, Tero; Heikkinen, Juha; Mäkinen, Jari; Nieminen, Tiina M

    2016-04-01

    Forest harvesting, especially when intensified harvesting method as whole-tree harvesting with stump lifting (WTHs) are used, may increase mercury (Hg) and methylmercury (MeHg) leaching to recipient water courses. The effect can be enhanced if the underlying bedrock and overburden soil contain Hg. The impact of stem-only harvesting (SOH) and WTHs on the concentrations of Hg and MeHg as well as several other variables in the ditch water was studied using a paired catchment approach in eight drained peatland-dominated catchments in Finland (2008-2012). Four of the catchments were on felsic bedrock and four on black schist bedrock containing heavy metals. Although both Hg and MeHg concentrations increased after harvesting in all treated sites according to the randomized intervention analyses (RIAs), there was only a weak indication of a harvest-induced mobilization of Hg and MeHg into the ditches. Furthermore, no clear differences between WTHs and SOH were found, although MeHg showed a nearly significant difference (p = 0.06) between the harvesting regimes. However, there was a clear bedrock effect, since the MeHg concentrations in the ditch water were higher at catchments on black schist than at those on felsic bedrock. The pH, suspended solid matter (SSM), dissolved organic carbon (DOC), and iron (Fe) concentrations increased after harvest while the sulfate (SO4-S) concentration decreased. The highest abundances of sulfate-reducing bacteria (SRB) were found on the sites with high MeHg concentrations. The biggest changes in ditch water concentrations occurred first 2 years after harvesting.

  16. SPECTRAL LINE SURVEY TOWARD THE YOUNG MASSIVE PROTOSTAR NGC 2264 CMM3 IN THE 4 mm, 3 mm, AND 0.8 mm BANDS

    SciTech Connect

    Watanabe, Yoshimasa; Sakai, Nami; López-Sepulcre, Ana; Furuya, Ryuta; Yamamoto, Satoshi; Sakai, Takeshi; Hirota, Tomoya; Liu, Sheng-Yuan; Su, Yu-Nung

    2015-08-20

    Spectral line survey observations are conducted toward the high-mass protostar candidate NGC 2264 CMM3 in the 4, 3, and 0.8 mm bands with the Nobeyama 45 m telescope and the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. In total, 265 emission lines are detected in the 4 and 3 mm bands, and 74 emission lines in the 0.8 mm band. As a result, 36 molecular species and 30 isotopologues are identified. In addition to the fundamental molecular species, many emission lines of carbon-chain molecules such as HC{sub 5}N, C{sub 4}H, CCS, and C{sub 3}S are detected in the 4 and 3 mm bands. Deuterated molecular species are also detected with relatively strong intensities. On the other hand, emission lines of complex organic molecules such as HCOOCH{sub 3} and CH{sub 3}OCH{sub 3} are found to be weak. For the molecules for which multiple transitions are detected, rotation temperatures are derived to be 7–33 K except for CH{sub 3}OH. Emission lines with high upper-state energies (E{sub u} > 150 K) are detected for CH{sub 3}OH, indicating the existence of a hot core. In comparison with the chemical composition of the Orion KL, carbon-chain molecules and deuterated molecules are found to be abundant in NGC 2264 CMM3, while sulfur-bearing species and complex organic molecules are deficient. These characteristics indicate the chemical youth of NGC 2264 CMM3 in spite of its location at the center of the cluster forming core, NGC 2264 C.

  17. Spectral Line Survey toward the Young Massive Protostar NGC 2264 CMM3 in the 4 mm, 3 mm, and 0.8 mm Bands

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshimasa; Sakai, Nami; López-Sepulcre, Ana; Furuya, Ryuta; Sakai, Takeshi; Hirota, Tomoya; Liu, Sheng-Yuan; Su, Yu-Nung; Yamamoto, Satoshi

    2015-08-01

    Spectral line survey observations are conducted toward the high-mass protostar candidate NGC 2264 CMM3 in the 4, 3, and 0.8 mm bands with the Nobeyama 45 m telescope and the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. In total, 265 emission lines are detected in the 4 and 3 mm bands, and 74 emission lines in the 0.8 mm band. As a result, 36 molecular species and 30 isotopologues are identified. In addition to the fundamental molecular species, many emission lines of carbon-chain molecules such as HC5N, C4H, CCS, and C3S are detected in the 4 and 3 mm bands. Deuterated molecular species are also detected with relatively strong intensities. On the other hand, emission lines of complex organic molecules such as HCOOCH3 and CH3OCH3 are found to be weak. For the molecules for which multiple transitions are detected, rotation temperatures are derived to be 7-33 K except for CH3OH. Emission lines with high upper-state energies (Eu > 150 K) are detected for CH3OH, indicating the existence of a hot core. In comparison with the chemical composition of the Orion KL, carbon-chain molecules and deuterated molecules are found to be abundant in NGC 2264 CMM3, while sulfur-bearing species and complex organic molecules are deficient. These characteristics indicate the chemical youth of NGC 2264 CMM3 in spite of its location at the center of the cluster forming core, NGC 2264 C.

  18. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    SciTech Connect

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Faleri, Claudia; Maida, Isabel; Fani, Renato

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  19. Long-lived Ar-Hg plasma in the afterglow of a high-current pulsed discharge

    SciTech Connect

    Sergeichev, K. F.; Lukina, N. A.; Fesenko, A. A.

    2013-02-15

    High-density (n > 10{sup 12} cm{sup -3}) argon-mercury plasma produced by a short (t {approx} 20 {mu}s) high-power pulsed discharge in argon with an admixture of mercury vapor at a discharge current of {approx}50 A, an argon pressure of {approx}4 mm Hg, and a mercury vapor pressure of {approx}10{sup -3} mm Hg was studied using optical spectroscopy and radio physics methods. It is found that the lifetime of this plasma after the end of the discharge pulse is up to 10{sup -2} s. It is shown that such an abnormally long lifetime of such an afterglow plasma, as compared to the plasma of an argon discharge without an admixture of mercury vapor, is related to the long residence time of atoms and ions of both argon and mercury in highly excited states due to chemi-ionization processes involving long-lived metastable argon ions. It is suggested that dissociative recombination of highly excited molecular ions of argon play an important role in the transfer of excitation to argon atoms and ions that are close to autoionization states.

  20. STATUS OF EPA/DOE MOU TECHNICAL WORKGROUP ACTIVITIES: HG WASTE TREATMENT

    EPA Science Inventory

    EPA's Land Disposal Restrictions program currently has technology-specific treatment standards for hazardous wastes containing greater than or equal to 260ppm total mercury (Hg) (i.e., high Hg subcategory wastes). The treatment standards specify RMERC for high Hg subcategory wast...

  1. 40 CFR 60.4120 - General Hg budget trading program permit requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false General Hg budget trading program... budget trading program permit requirements. (a) For each Hg Budget source required to have a title V operating permit, such permit shall include a Hg Budget permit administered by the permitting authority...

  2. Phytoextraction of HG by parsley (Petroselinum crispum) and its growth responses.

    PubMed

    Bibi, Asma; Farooq, Umar; Naz, Sadia; Khan, Afsar; Khan, Sara; Sarwar, Rizwana; Mahmood, Qaisar; Alam, Arif; Mirza, Nosheen

    2016-01-01

    The effect of mercury (Hg) on the growth and survival of parsley (Petroselinum crispum) was explored at various treatments. The plants were grown in pots having Hoagland's solution to which various Hg treatments were applied and placed under greenhouse conditions. The treatments were: no metal applied (control) and six doses of Hg as mercuric chloride for 15 days. Linear trend of Hg accumulation was noted in roots, stems, and leaves with increasing Hg treatments. The maximum Hg concentration in root, stem and leaf was 8.92, 8.27, and 7.88 at Hg treatments of 25 mg l(-1), respectively. On the whole, Hg accumulation in different plant parts was in the following order: leaves > stem > roots. Linear trend was also observed for Bioaccumulation Factor (BF) and Translocation Factor (TF) with increasing Hg concentrations in the growth medium. The highest respective BFHg and TFHg values were 9.32 and 2.02 for the Hg treatments of 25 and 50 mg l(-1). In spite of the reduced growth in the presence of Hg, the plant has phytoremediation potential. It is recommended that parsley should not be cultivated in Hg contaminated sites in order to avoid dietary toxicity.

  3. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with... sub-contracts. Salary Supplements for HG Employees (OCT 1998) (a) Salary supplements are payments...

  4. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with... sub-contracts. Salary Supplements for HG Employees (OCT 1998) (a) Salary supplements are payments...

  5. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with... sub-contracts. Salary Supplements for HG Employees (OCT 1998) (a) Salary supplements are payments...

  6. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with... sub-contracts. Salary Supplements for HG Employees (OCT 1998) (a) Salary supplements are payments...

  7. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with... sub-contracts. Salary Supplements for HG Employees (OCT 1998) (a) Salary supplements are payments...

  8. Solution speciation controls mercury isotope fractionation of Hg(II) sorption to goethite.

    PubMed

    Jiskra, Martin; Wiederhold, Jan G; Bourdon, Bernard; Kretzschmar, Ruben

    2012-06-19

    The application of Hg isotope signatures as tracers for environmental Hg cycling requires the determination of isotope fractionation factors and mechanisms for individual processes. Here, we investigated Hg isotope fractionation of Hg(II) sorption to goethite in batch systems under different experimental conditions. We observed a mass-dependent enrichment of light Hg isotopes on the goethite surface relative to dissolved Hg (ε(202)Hg of -0.30‰ to -0.44‰) which was independent of the pH, chloride and sulfate concentration, type of surface complex, and equilibration time. Based on previous theoretical equilibrium fractionation factors, we propose that Hg isotope fractionation of Hg(II) sorption to goethite is controlled by an equilibrium isotope effect between Hg(II) solution species, expressed on the mineral surface by the adsorption of the cationic solution species. In contrast, the formation of outer-sphere complexes and subsequent conformation changes to different inner-sphere complexes appeared to have insignificant effects on the observed isotope fractionation. Our findings emphasize the importance of solution speciation in metal isotope sorption studies and suggest that the dissolved Hg(II) pool in soils and sediments, which is the most mobile and bioavailable, should be isotopically heavy, as light Hg isotopes are preferentially sequestered during binding to both mineral phases and natural organic matter.

  9. Characteristics of Hg-resistant bacteria isolated from Minamata Bay sediment

    SciTech Connect

    Nakamura, K.; Fujisaki, T.; Tamashiro, H.

    1986-06-01

    Seventy-two strains of Hg-resistant bacteria (Pseudomonas) were isolated on agar plates containing 40 micrograms/ml of HgCl2 from Minamata Bay sediment, which was heavily polluted with mercury (45.8 micrograms/g). The minimal inhibitory concentrations (MICs) of mercurial compounds were determined for the Hg-resistant pseudomonads and 65 strains (Pseudomonas sp., Bacillus sp., Vibrio sp., and Corynebacterium sp.) isolated from Sendai Bay sediment (1 microgram/g of mercury) as control. The MICs to HgCl/sub 2/, CH/sub 3/HgCl, C/sub 2/H/sub 5/HgCl, C/sub 3/H/sub 7/HgCl, and C/sub 6/H/sub 5/HgOCOCH/sub 3/ for the Hg-resistant pseudomonads from Minamata Bay were significantly higher than those of strains from Sendai Bay. The volatilization from liquid culture containing 20 micrograms/ml of HgCl2 was observed in all of the Hg-resistant pseudomonads from Minamata Bay (70 strains). The mean loss of mercury from liquid culture was 60.4 +/- 17.3%. Further study is warranted to determine what role the Hg-resistant bacteria, particularly the Pseudomonas species, play in the mercury cycle in Minamata Bay.

  10. A solid-state 199Hg NMR study of mercury halides

    NASA Astrophysics Data System (ADS)

    Taylor, R. E.; Bai, Shi; Dybowski, C.

    2011-02-01

    The principal elements of the 199Hg chemical-shift (CS) tensors of the mercuric halides (HgX 2, X = F, Cl, Br, and I) and the mercurous halides (Hg 2X 2, X = F and Cl) were determined from spectra of static polycrystalline powders and from magic-angle spinning (MAS) spectra. The CS tensors of both HgCl 2 and Hg 2Cl 2 are axially symmetric ( η = 0) within experimental error, differing from literature reports of η = 0.12 and η = 0.14, respectively. The principal elements of the axially symmetric CS tensor in HgBr 2 were also measured using a static sample, and the wideline spectra of HgF 2 and HgI 2 (red polymorph) give chemical-shift tensors that suggest, within experimental error, that the mercury sits in sites of cubic symmetry. The 199Hg CS tensor for Hg 2F 2 is asymmetric. Experiments with static polycrystalline samples may allow the determination of the elements of the 199Hg CS tensors even when MAS fails to completely average the dipolar coupling of the spin-½ 199Hg and the quadrupolar halide nucleus.

  11. Dimercaptopropane Sulfonate Chelation Affects In Vivo Hg and MeHg Distribution in Tissues and Urine of Prairie Voles (Microtus ochrogaster).

    PubMed

    Cobb, G P; Moore, A W; Rummel, K T; McMurry, S T

    2015-12-01

    Methyl mercury cation (MeHg(+)) and divalent mercury (Hg(2+)) were quantified in urine, liver, kidney, and brain of prairie voles (Microtus ochrogaster) during a 12 week exposure to aqueous MeHg(+) at concentrations of 10, 100, and 1000 ng MeHg(+)/mL. Aqueous MeHg(+) exposures increased mercury accumulation in tissues of voles from each exposure group. Accumulation was greater within the higher two exposure groups. Similar [Hg(2+)] and [MeHg(+)] were determined within a given organ type before and after 2,3-dimercapto-1-propane sulfonate (DMPS) chelation. Similar correlations were seen for Hg(2+) and MeHg(+) concentrations in pre and post chelation urine. Post chelation urine more reliably predicted mercury species concentrations in tissues than did urine collected before chelation. These data demonstrate the utility of DMPS in noninvasive assessment of wildlife exposure to mercury, which may have utility in evaluating meta-population level exposure to hazardous wastes.

  12. Practical and regenerable electrochemical aptasensor based on nanoporous gold and thymine-Hg(2+)-thymine base pairs for Hg(2+) detection.

    PubMed

    Zeng, Guangming; Zhang, Chen; Huang, Danlian; Lai, Cui; Tang, Lin; Zhou, Yaoyu; Xu, Piao; Wang, Hou; Qin, Lei; Cheng, Min

    2017-04-15

    A simple, practical and reusable electrochemical aptasensor, based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and nanoporous gold (NPG) for signal amplification, was designed for sensitive and selective detection of mercury ions (Hg(2+)). The thiol modified T-rich hairpin capture probe was self-assembled onto the surface of the NPG modified electrode for hybridizing with ferrocene-labeled T-rich probe in the presence of Hg(2+) via T-Hg(2+)-T coordination chemistry. As a result, the hairpin capture probe was opened, and the ferrocene tags were close to the NPG modified electrode. Taking advantage of the amplification effect of NPG electrode for increasing the reaction sites of thiol modified capture probe, the proposed electrochemical aptasensor could detect Hg(2+) quantitatively in the range of 0.01-5000nM, with a detection limit as low as 0.0036nM which is much lower than the maximum contamination level for Hg(2+) in drinking water defined by the U.S. Environmental Protection Agency. Moreover, the proposed electrochemical aptasensor can be regenerated by adding cysteine and Mg(2+). The aptasensor was also used to detect Hg(2+) from real water samples, and the results showed excellent agreement with the values determined by atomic fluorescence spectrometer. This aptasensor showed a promising potential for on-site detecting Hg(2+) in drinking water.

  13. The new Hg-rich barium indium mercurides BaInxHg7-x (x=3.1) and BaInxHg11-x (x=0-2.8). Synthesis, crystal and electronic structure

    NASA Astrophysics Data System (ADS)

    Wendorff, Marco; Schwarz, Michael; Röhr, Caroline

    2013-07-01

    The title compounds BaInxHg7-x (x=3.1(1)) and BaInxHg11-x (x=0-2.8) were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures have been determined using single crystal X-ray data. BaInxHg7-x (x=3.1(1)) crystallizes in a new structure type (orthorhombic, oC16, space group Cmmm: a=512.02(1), b=1227.68(3), c=668.61(2) pm, Z=2, R1=0.0311). In the structure, the atoms of the three crystallographically different mixed In/Hg positions form planar nets of four-, six- and eight-membered rings. These nets are shifted against each other such that the four-membered rings form empty distorted cubes. The cubes are connected via common edges, corners and folded ladders, which are also found in BaIn2/BaHg2 (KHg2 structure type) and BaIn (α-NaHg type). The Ba atoms are centered in the eight-membered rings and exhibit an overall coordination number of 20. The [BaM20] polyhedra and twice as many distorted [M8] cubes tesselate the space. BaIn2.8Hg8.2 (cubic, cP36, space group Pm3barm, a=961.83(1) pm, Z=3, R1=0.0243) is the border compound of the phase width BaInxHg11-x of the rare BaHg11 structure type. In the structure, ideal [M8] cubes (at the corners of the unit cell) and BaM20 polyhedra (at the edges of the unit cell) represent the building blocks comparable to the other new In mercuride. In accordance with the increased In/Hg content, additional M-pure regions appear: the center of the unit cell contains a huge [Hg(1)M(2)12M(3,4)32] polyhedron, a Hg-centered cuboctahedron of In/Hg atoms surrounded by a capped cantellated cube of 32 additional M atoms. For both structure types, the bonding situation and the ‘coloring’, i.e. the In/Hg distribution of the polyanionic network, are discussed considering the different sizes of the atoms and the charge distribution (Bader AIM charges), which have been calculated within the framework of FP-LAPW density functional theory.

  14. Innate stimulatory capacity of high molecular weight transition metals Au (gold) and Hg (mercury).

    PubMed

    Rachmawati, Dessy; Alsalem, Inás W A; Bontkes, Hetty J; Verstege, Marleen I; Gibbs, Sue; von Blomberg, B M E; Scheper, Rik J; van Hoogstraten, Ingrid M W

    2015-03-01

    Nickel, cobalt and palladium ions can induce an innate immune response by triggering Toll-like receptor (TLR)-4 which is present on dendritic cells (DC). Here we studied mechanisms of action for DC immunotoxicity to gold and mercury. Next to gold (Na3Au (S2O3)2⋅2H2O) and mercury (HgCl2), nickel (NiCl2) was included as a positive control. MoDC activation was assessed by release of the pro-inflammatory mediator IL-8. Also PBMC were studied, and THP-1 cells were used as a substitution for DC for evaluation of cytokines and chemokines, as well as phenotypic, alterations in response to gold and mercury. Our results showed that both Na3Au (S2O3)2⋅2H2O and HgCl2 induce substantial release of IL-8, but not IL-6, CCL2 or IL-10, from MoDc, PBMC, or THP-1 cells. Also gold and, to a lesser extent mercury, caused modest dendritic cell maturation as detected by increased membrane expression of CD40 and CD80. Both metals thus show innate immune response capacities, although to a lower extent than reported earlier for NiCl2, CoCl2 and Na2 [PdCl4]. Importantly, the gold-induced response could be ascribed to TLR3 rather than TLR4 triggering, whereas the nature of the innate mercury response remains to be clarified. In conclusion both gold and mercury can induce innate immune responses, which for gold could be ascribed to TLR3 dependent signalling. These responses are likely to contribute to adaptive immune responses to these metals, as reflected by skin and mucosal allergies.

  15. A Highly Sensitive Multi-Element HgCdTe E-APD Detector for IPDA Lidar Applications

    NASA Technical Reports Server (NTRS)

    Beck, Jeff; Welch, Terry; Mitra, Pradip; Reiff, Kirk; Sun, Xiaoli; Abshire, James

    2014-01-01

    An HgCdTe electron avalanche photodiode (e-APD) detector has been developed for lidar receivers, one application of which is integrated path differential absorption lidar measurements of such atmospheric trace gases as CO2 and CH4. The HgCdTe APD has a wide, visible to mid-wave-infrared, spectral response, high dynamic range, substantially improved sensitivity, and an expected improvement in operational lifetime. A demonstration sensor-chip assembly consisting of a 4.3 lm cutoff HgCdTe 4 9 4 APD detector array with 80 micrometer pitch pixels and a custom complementary metal-oxide-semiconductor readout integrated circuit was developed. For one typical array the APD gain was 654 at 12 V with corresponding gain normalized dark currents ranging from 1.2 fA to 3.2 fA. The 4 9 4 detector system was characterized at 77 K with a 1.55 micrometer wavelength, 1 microsecond wide, laser pulse. The measured unit gain detector photon conversion efficiency was 91.1%. At 11 V bias the mean measured APD gain at 77 K was 307.8 with sigma/mean uniformity of 1.23%. The average, noise-bandwidth normalized, system noise-equivalent power (NEP) was 1.04 fW/Hz(exp 1/2) with a sigma/mean of 3.8%. The measured, electronics-limited, bandwidth of 6.8 MHz was more than adequate for 1 microsecond pulse detection. The system had an NEP (3 MHz) of 0.4 fW/Hz(exp 1/2) at 12 V APD bias and a linear dynamic range close to 1000. A gain-independent quantum-limited SNR of 80% of full theoretical was indicative of a gain-independent excess noise factor very close to 1.0 and the expected APD mode quantum efficiency.

  16. A Highly Sensitive Multi-element HgCdTe e-APD Detector for IPDA Lidar Applications

    NASA Astrophysics Data System (ADS)

    Beck, Jeff; Welch, Terry; Mitra, Pradip; Reiff, Kirk; Sun, Xiaoli; Abshire, James

    2014-08-01

    An HgCdTe electron avalanche photodiode (e-APD) detector has been developed for lidar receivers, one application of which is integrated path differential absorption lidar measurements of such atmospheric trace gases as CO2 and CH4. The HgCdTe APD has a wide, visible to mid-wave-infrared, spectral response, high dynamic range, substantially improved sensitivity, and an expected improvement in operational lifetime. A demonstration sensor-chip assembly consisting of a 4.3 μm cutoff HgCdTe 4 × 4 APD detector array with 80 μm pitch pixels and a custom complementary metal-oxide-semiconductor readout integrated circuit was developed. For one typical array the APD gain was 654 at 12 V with corresponding gain normalized dark currents ranging from 1.2 fA to 3.2 fA. The 4 × 4 detector system was characterized at 77 K with a 1.55 μm wavelength, 1 μs wide, laser pulse. The measured unit gain detector photon conversion efficiency was 91.1%. At 11 V bias the mean measured APD gain at 77 K was 307.8 with σ/mean uniformity of 1.23%. The average, noise-bandwidth normalized, system noise-equivalent power (NEP) was 1.04 fW/Hz1/2 with a σ/mean of 3.8%. The measured, electronics-limited, bandwidth of 6.8 MHz was more than adequate for 1 μs pulse detection. The system had an NEP (3 MHz) of 0.4 fW/Hz1/2 at 12 V APD bias and a linear dynamic range close to 1000. A gain-independent quantum-limited SNR of 80% of full theoretical was indicative of a gain-independent excess noise factor very close to 1.0 and the expected APD mode quantum efficiency.

  17. 47 CFR 80.273 - Radar standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Radar standards. 80.273 Section 80.273... MARITIME SERVICES Equipment Authorization for Compulsory Ships § 80.273 Radar standards. (a) Radar... with radar must comply with the following standards (all incorporated by reference, see § 80.7):...

  18. 47 CFR 80.273 - Radar standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Radar standards. 80.273 Section 80.273... MARITIME SERVICES Equipment Authorization for Compulsory Ships § 80.273 Radar standards. (a) Radar... with radar must comply with the following standards (all incorporated by reference, see § 80.7):...

  19. 47 CFR 80.273 - Radar standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Radar standards. 80.273 Section 80.273... MARITIME SERVICES Equipment Authorization for Compulsory Ships § 80.273 Radar standards. (a) Radar... with radar must comply with the following standards (all incorporated by reference, see § 80.7):...

  20. 47 CFR 80.923 - Antenna system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  1. 47 CFR 80.923 - Antenna system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  2. 47 CFR 80.923 - Antenna system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  3. 47 CFR 80.923 - Antenna system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  4. 47 CFR 80.923 - Antenna system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Antenna system. 80.923 Section 80.923... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.923 Antenna system. An antenna must be provided in accordance with the applicable requirements of § 80.81 of this...

  5. 46 CFR 80.10 - Applicability.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Applicability. 80.10 Section 80.10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS DISCLOSURE OF SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.10 Applicability. Except as exempted in § 80.20, this part applies to— (a) Owners,...

  6. 46 CFR 80.10 - Applicability.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Applicability. 80.10 Section 80.10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS DISCLOSURE OF SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.10 Applicability. Except as exempted in § 80.20, this part applies to— (a) Owners,...

  7. 46 CFR 80.10 - Applicability.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Applicability. 80.10 Section 80.10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS DISCLOSURE OF SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.10 Applicability. Except as exempted in § 80.20, this part applies to— (a) Owners,...

  8. 46 CFR 80.10 - Applicability.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Applicability. 80.10 Section 80.10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS DISCLOSURE OF SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.10 Applicability. Except as exempted in § 80.20, this part applies to— (a) Owners,...

  9. 46 CFR 80.10 - Applicability.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Applicability. 80.10 Section 80.10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS DISCLOSURE OF SAFETY STANDARDS AND COUNTRY OF REGISTRY § 80.10 Applicability. Except as exempted in § 80.20, this part applies to— (a) Owners,...

  10. Hole Transport in Arsenic-Doped Hg1- x Cd x Te with x ≥ 0.5

    NASA Astrophysics Data System (ADS)

    Umana-Membreno, G. A.; Kala, H.; Bains, S.; Akhavan, N. D.; Antoszewski, J.; Maxey, C. D.; Faraone, L.

    2016-09-01

    Hole transport in arsenic-doped p-type Hg1- x Cd x Te epitaxial layers with x ≥ 0.5 has been studied employing Hall-effect measurements and theoretical modeling of hole scattering mechanisms. The hole transport parameters extracted from four different Hg1- x Cd x Te films with x = 0.50, 0.56-0.58, 0.65, and 0.80, were analyzed using an iterative solution of Boltzmann's transport equation. Hole mobilities in the samples with x values of 0.5 and 0.56-0.58 were found to be predominantly limited by ionized impurity scattering, and exhibited relatively high impurity compensation ratios ≥2. The sample with x = 0.65 exhibited the highest hole mobility, a low compensation ratio of 1.05, and mobility characteristics were limited predominantly by polar optical phonon scattering at temperatures ≥200 K. Hole mobility in the sample with x = 0.80 was found to be limited by polar optical phonon scattering and ionized impurity scattering (compensation ratio 1.20-1.56). Although the sample temperatures employed were not sufficiently low to unambiguously discriminate the scattering strength of static strain and dislocations, the experimental hole mobility characteristics cannot be adequately modeled if these two mechanisms are neglected. The ionization energy of the arsenic acceptor impurities was found to exhibit a quadratic dependence on the CdTe mole fraction.

  11. Sagitally focusing scanning monochromator produces 0.4-mm focus (abstract)

    NASA Astrophysics Data System (ADS)

    Rosenbaum, G.; Sullivan, M.; Fischetti, R.; Rock, L.

    1992-01-01

    A sagitally focusing stage has been constructed for the double-crystal scanning monochromator on beam line X9-A at the NSLS which can be exchanged with the normally used flat crystal stage. The bending device located at 12.0 m from the source is designed to accept a beam up to 200-mm wide. The monochromator with bending stage can be scanned over Bragg angles from 10° to 71° corresponding to photon energies from 11.4 to 2.1 keV with Si-111 crystals. In conjunction with the vertically focusing mirror a point focus of 0.38 mm×0.18 mm [horizontal×vertical, full width at half maximum (FWHM) each] has been achieved at a focal length of 3.8 m (center of a four-circle diffractometer). Focused at the back of the experimental hutch (focal length=5.4 m) the focal size was 0.55 mm×0.30 mm. The measured horizontal width of the focus equals the calculated size of the demagnified source and is independent of the horizontal convergence used. The horizontal focus produced by the crystal is very clean: the full width at 1% of maximum is 1.5 mm and at 0.01% it is about 4 mm. The flux into the focus is 5×1011 photons/s at a photon energy of 7.4 keV and beam current of 200 mA. The average flux density in the center of the focus (FWHM area) is 5×1011 photons/s/mm2. The preliminary crystal presently used has been made from a thin Si plate of 0.4-mm thickness, 80-mm width, and 75-mm length (in the direction of the beam). Steel ribs of 0.6-mm thickness have been glued at 3-mm pitch to the back of the crystal in order to stiffen the plate and reduce anticlastic bending.1 Plates have been glued to this crystal plate to extend the width to size the bending stage. The crystal was cut in 111 orientation with a 4° angle between the lattice planes and the crystal surface. The asymmetric cut was used to increase the angle of incidence and thus decrease the effect of the remaining anticlastic bending. The bending stage has a bending couple at both ends of the crystal in order to produce the

  12. Apparatus for growing HgI.sub.2 crystals

    DOEpatents

    Schieber, Michael M.; Beinglass, Israel; Dishon, Giora

    1978-01-01

    A method and horizontal furnace for vapor phase growth of HgI.sub.2 crystals which utilizes controlled axial and radial airflow to maintain the desired temperature gradients. The ampoule containing the source material is rotated while axial and radial air tubes are moved in opposite directions during crystal growth to maintain a desired distance and associated temperature gradient with respect to the growing crystal, whereby the crystal interface can advance in all directions, i.e., radial and axial according to the crystallographic structure of the crystal. Crystals grown by this method are particularly applicable for use as room-temperature nuclear radiation detectors.

  13. Interface Chemistry of Hg(1-x)Cd(x)Te.

    DTIC Science & Technology

    1985-05-08

    8217.’ * . ." ’C . -2- Mercury- Cadmium -Telluride is probably the most studied ternary semiconductor in recent years because of its widespread application for...grown at McDonnell Douglas Research Laboratories using a modified Bridgman method. The bulk crystals exhibited a band gap of 0.175±0.01 eV and p-type...Sulphides, Selenides and Tellurides, Butterworths, London, 1974. Therefore, the formation of Cr-Te phases at the HgCdTe-Cr interface should be

  14. HgCdTe Surface and Defect Study Program.

    DTIC Science & Technology

    1983-07-01

    as "independent" entities as is the case (to the first approximation) with all other semiconductors studied to date. These results have given rise to...all cases but one (Prof. Walter Harrison’s invited paper on the theory of bonding in MCT) have been written up as full articles for the conference...properties. In the case of PhotoxT Si0 2 on HgCdTe, the inter- face state structure which is controlled by the details of the bonding at the interface

  15. Lattice-Matched HgZnTe Epitaxy Development.

    DTIC Science & Technology

    1988-04-01

    7 D- 193 6?? LATTICE- ATCHED HGZNTE EPITRXY DEVELOPMENT(U) MERCURY 1/1 UNCRSIFI3 ?? F33615-86-C-5185 AFWL-TR-S?-4133 Uw : AS ID F/C 20/2 NL...8217"., + ._ _ N A. AFWAL-TR-87-4133 QLATTICE-MATCHED HgZnTe EPITAXY DEVELOPMENT 0David G. Ryding Mercury L.P.E. Company, Inc. Pittsburg, PA 15238 April 1988...6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION Mercury L.P.E. Company, Inc. (Ifapplicable) Air Force Wright

  16. MOS structures based on epitaxial HgCdTe layers

    SciTech Connect

    Antonov, V.V.; Belashov, Y.G.; Kazak, E.P.; Mezentseva, M.P.; Voitsekhovskii, A.V.

    1985-08-01

    The authors present the results of a study of the dependence of the surface photoelectromotive force at wavelengths of 3.39 and 10.6 micrometers on the field electrode for MOS structures prepared from epitaxial Hg /SUB 1-x/ Cd /SUB x/ Te layers (x=0.20-0.25). They analyze the nature of the inhomogeneities in the region near the surface of semiconducting samples prepared under various heat treatment conditions and present their findings in a series of three charts.

  17. HCN Producing Bacteria Enable Sensing Of Non-Bioavailable Hg Species by the Whole Cell Biosensor

    NASA Astrophysics Data System (ADS)

    Horvat, M.; Rijavec, T.; Koron, N.; Lapanje, A.

    2015-12-01

    Bacteria play an important role in Hg transformation reactions. The production of cyanide (HCN) and other secondary metabolites seems to be key elements involved in these transformations. Current hypotheses link the role of HCN production to growth inhibition of nonHCN producing competitor organisms (role of an antimicrobial agent). Our past investigations showed that HCN production did not correlate with antimicrobial activity and since pK value of HCN is very high (pK = 9,21), it can be expected that most of the produced HCN is removed from the microenvironment. This way, the expected inhibitory concentrations can hardly be reached. Accordingly, we proposed a new concept, where the ability of complexation of transient metals by HCN served as a regulation process for the accessibility of micro-elements. In our study, we focused on the presence of HCN producing bacteria and carried it out in the Hg contaminated environment connected to the Idrija Mercury Mine, Slovenia. We characterised the isolates according to the presence of Hg resistance (HgR), level of HCN production and genetic similarities. In laboratory setups, using our merR whole cell based biosensor, we determined the transformation of low bioavailable Hg0 and HgS forms into bioavailable Hg by these HCN producing bacteria. We observed that HgR strains producing HCN had the highest impact on increased Hg bioavailability. In the proposed ecological strategy HgR HCN producing bacteria increase their competitive edge over non-HgR competitors through the increase of Hg toxicity. Due to their activity, Hg is made available to other organisms as well and thus enters into the ecosystem. Finally, using some of the characteristics of bacteria (e.g. Hg resistance genetic elements), we developed a fully automated sensing approach, combining biosensorics and mechatronics, to measure the bioavailability of Hg in situ.

  18. Identification of proteins involved in Hg-Se antagonism in water hyacinth (Eichhornia crassipes).

    PubMed

    Pacheco, Pablo; Hanley, Traci; Figueroa, Julio A Landero

    2014-03-01

    Different studies have established the presence of a proteinaceus complex involved in Hg-Se agonism/antagonism in plants. In order to identify proteins involved in this mechanism, water hyacinth plants were divided into groups and supplemented with Hg, Se and a Hg-Se mixture. Proteins involved were identified through a screening separation by SEC-ICPMS followed by SAX-ICPMS and then peptide mapping of selected fractions by nanoLC-ESI-ITMS(2). Determination of total metal concentration showed that Se inhibits Hg translocation from roots to aerial compartments of the plant and that Se and Hg are antagonists to each other in terms of plant toxicity. In roots, stems and leaves Se was distributed mainly in two molecular mass fractions <670 kDa and ∼40 kDa, however, the proportion between these two fractions was inverted when Hg was co-administered. Hg throughout the plant was distributed in high and medium molecular mass compounds. Hg associated with molecules, ranging from <1.5 kDa to 15 kDa, was found in the root extract of Hg(ii) supplemented plants, but was absent in the root extract of Se(iv) and Hg(ii) supplemented plants. SAX showed that Hg and Se were mostly not associated with the same entity, since the complete overlapping of Hg and Se signals in all the peaks of SEC chromatograms was not observed. Changes in Se and Hg levels in water hyacinth were more evident in leaves in contrast to other compartments. Several proteins, possibly associated with either Se or Hg, were identified in roots, stems and leaves. Most of the identified proteins were associated with Hg and located in leaves, and these are associated specifically with chloroplast and mitochondria proteins, related to essential mechanisms in plants such as photosynthesis, carbon fixation and the electron transport chain.

  19. The same-source parallel MM{sub 5}.

    SciTech Connect

    Michalakes, J.

    1999-08-23

    The set of architectures available to users of the Penn State/NCAR MM5 has been expanded to included distributed-memory parallel computers, providing cost-effective scalable performance and memory capacity for large problem sizes. The same-source approach uses high-level parallel library and source-translation technology for adapting MM5, simplifying maintenance and allowing new physics modules to be incorporated without modification. The approach facilitates maintenance of the DM-parallel option to MM5 as an option within the official version, rather than as a separate stand-alone version. As a result, the DM-parallel option to MM5 (now at Version 3.1) has been a part of six subsequent model releases since MM5 Version 2.8 in March 1998. The same-source approach is applicable to other, similarly constructed codes when there is a need or desire to develop the code for distributed memory parallel machines without impacting the pre-existing source code. The approach is also compatible with pre-existing loop-level multithreading directives so that the code will run in distributed-memory/shared-memory mode on SMP clusters.

  20. CMOS mm-wave transceivers for Gbps wireless communication

    NASA Astrophysics Data System (ADS)

    Baoyong, Chi; Zheng, Song; Lixue, Kuang; Haikun, Jia; Xiangyu, Meng; Zhihua, Wang

    2016-07-01

    The challenges in the design of CMOS millimeter-wave (mm-wave) transceiver for Gbps wireless communication are discussed. To support the Gbps data rate, the link bandwidth of the receiver/transmitter must be wide enough, which puts a lot of pressure on the mm-wave front-end as well as on the baseband circuit. This paper discusses the effects of the limited link bandwidth on the transceiver system performance and overviews the bandwidth expansion techniques for mm-wave amplifiers and IF programmable gain amplifier. Furthermore, dual-mode power amplifier (PA) and self-healing technique are introduced to improve the PA's average efficiency and to deal with the process, voltage, and temperature variation issue, respectively. Several fully-integrated CMOS mm-wave transceivers are also presented to give a short overview on the state-of-the-art mm-wave transceivers. Project supported in part by the National Natural Science Foundation of China (No. 61331003).

  1. Dislocation Reduction of HgCdTe/Si Through Ex Situ Annealing

    DTIC Science & Technology

    2016-06-07

    REPORT Dislocation Reduction of HgCdTe/Si Through Ex Situ Annealing 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Current growth methods of HgCdTe/Cd(Se...Z39.18 - Dislocation Reduction of HgCdTe/Si Through Ex Situ Annealing Report Title ABSTRACT Current growth methods of HgCdTe/Cd(Se)Te/Si by molecular... growth methods of HgCdTe/Cd(Se)Te/Si by molecular-beam epitaxy (MBE) result in a dislocation density of mid 106 cm2 to low 107 cm2. Although the exact

  2. Lifetime measurements of yrast and excited superdeformed bands in {sup 192,193}Hg

    SciTech Connect

    Busse, B.C.; Fallon, P.; Kruecken, R.; Asztalos, S.J.; Clark, R.M.; Deleplanque, M.A.; Diamond, R.M.; Lee, I.Y.; Macchiavelli, A.O.; MacLeod, R.W.; Schmid, G.; Stephens, F.S.; Vetter, K.; Ackermann, D.; Ahmad, I.; Blumenthal, D.J.; Carpenter, M.P.; Fischer, S.M.; Janssens, R.V.; Khoo, T.L.; Lauritsen, T.; Nisius, D.; Seweryniak, D.; Moore, E.F.; Hannachi, F.; Lopez-Martens, A.; Korichi, A.

    1998-03-01

    Quadrupole moments of the six known superdeformed (SD) bands of {sup 193}Hg and the yrast SD band of {sup 192}Hg have been determined by a Doppler-shift-attenuation-method measurement utilizing the gammasphere array. The quadrupole moments of all {sup 193}Hg SD bands were found to be similar, suggesting the active single-particle orbitals in the mass-190 region exhibit only small shape-driving effects. Additionally, there is evidence for an unexpected difference in the quadrupole moments of SD bands in {sup 192}Hg and {sup 193}Hg. {copyright} {ital 1998} {ital The American Physical Society}

  3. Differential lifetime measurements and identical superdeformed bands in {sup 192,194}Hg

    SciTech Connect

    Moore, E.F.; Amro, H.; Lauritsen, T.; Janssens, R.V.; Khoo, T.L.; Ackermann, D.; Ahmad, I.; Amro, H.; Blumenthal, D.; Carpenter, M.P.; Fischer, S.M.; Hackman, G.; Nisius, D.; Hannachi, F.; Lopez-Martens, A.; Korichi, A.; Asztalos, S.; Clark, R.M.; Deleplanque, M.A.; Diamond, R.M.; Fallon, P.; Lee, I.Y.; Macchiavelli, A.O.; Stephens, F.S.; Becker, J.A.; Bernstein, L.; Farris, L.P.; Henry, E.A.

    1997-05-01

    High-precision lifetime measurements have been performed in superdeformed (SD) bands of {sup 192,194}Hg with the Doppler-shift attenuation method. Intrinsic quadrupole moments Q{sub 0} were extracted for three SD bands in {sup 194}Hg and for the yrast SD band in {sup 192}Hg. Within experimental uncertainties, all four SD bands have equal Q{sub 0} values. These results provide constraints on differences in Q{sub 0} values between the {open_quotes}identical{close_quotes} SD bands {sup 194}Hg(3) and {sup 192}Hg(1). {copyright} {ital 1997} {ital The American Physical Society}

  4. Synthesis and growth of HgI{sub 2} nanocrystals in a glass matrix: Heat treatment

    SciTech Connect

    Condeles, J. F. E-mail: ricssilva@yahoo.com.br; Silva, R. S. E-mail: ricssilva@yahoo.com.br; Silva, A. C. A.; Dantas, N. O.

    2014-08-14

    Mercury iodide (HgI{sub 2}) nanocrystals (NCs) were successfully grown in a barium phosphate glass matrix synthesized by fusion. Growth control of HgI{sub 2} NCs was investigated by Atomic Force Microscopy (AFM), Optical Absorption (OA), Fluorescence (FL), and X-ray diffraction (XRD). AFM images reveal the formation of HgI{sub 2} nanocrystals in host glass matrix. HgI{sub 2} NCs growth was evidenced by an OA and FL band red-shift with increasing annealing time. XRD measurements revealed the β crystalline phase of the HgI{sub 2} nanocrystals.

  5. New Methods for Exploring QM:MM Potential Energy Landscapes

    NASA Astrophysics Data System (ADS)

    Hratchian, Hrant P.

    2010-06-01

    In recent years, the applicability of quantum chemical methods for large system studies has been greatly enhanced by the development of hybrid QM:MM techniques. Despite these advancements, exploring the associated potential energy surfaces continues to present two key challenges. First, the QM energy and derivative evaluations may be too costly for simulations; and second, the system size for many QM:MM cases are too large to effectively store or use second-order information, an approach often used in QM studies to allow for larger integration steps and fewer QM evaluations of the potential energy surface. Our most recent work is focused on overcoming both computational bottlenecks. Using surface fitting models together with direct Hessian-vector and diagonalization algorithms, we are developing models that can accurately and efficiently explore QM:MM potential energy landscapes for very large systems. Our current development status and results from initial applications will be described.

  6. QM/MM X-ray Refinement of Zinc Metalloenzymes

    PubMed Central

    Li, Xue; Hayik, Seth A.; Merz, Kenneth M.

    2010-01-01

    Zinc metalloenzymes play an important role in biology. However, due to the limitation of molecular force field energy restraints used in X-ray refinement at medium or low resolutions, the precise geometry of the zinc coordination environment can be difficult to distinguish from ambiguous electron density maps. Due to the difficulties involved in defining accurate force fields for metal ions, the QM/MM (Quantum-Mechanical /Molecular-Mechanical) method provides an attractive and more general alternative for the study and refinement of metalloprotein active sites. Herein we present three examples that indicate that QM/MM based refinement yields a superior description of the crystal structure based on R and Rfree values and on the inspection of the zinc coordination environment. It is concluded that QM/MM refinement is a useful general tool for the improvement of the metal coordination sphere in metalloenzyme active sites. PMID:20116858

  7. Radiosurgery With or Without A 2-mm Margin for 93 Single Brain Metastases

    SciTech Connect

    Nataf, Francois; Schlienger, Michel Liu Zhihua; Foulquier, Jean Noel; Gres, Benoit; Orthuon, Alexandre; Vannetzel, Jean Michel; Escudier, Bernard; Meder, Jean- Francois; Roux, Francois Xavier; Touboul, Emmanuel

    2008-03-01

    Purpose: Retrospective comparison of Linac radiosurgery (RS) in 93 single brain metastases with or without a 2-mm margin. Patients and Methods: A total of 153 patients had Linac RS (between April 1992 and June 2004), with 139 patients (90.8%) evaluable in June 2005. Sixty-one patients (44%) had extracranial lesions and 65 patients had neurologic symptoms (47%). RS alone: 105 patients (66%); RS +whole brain radiotherapy: 34 patients (24%). Single metastasis: 93/139 patients; classic RS: 42/93 patients; 2-mm margin: 51/93 patients; 30 multiple lesions patients were excluded. Treatment: 15 Mv X-ray Linac, circular minibeams, 8-30 mm, four to six noncoplanar coronal arcs. Isodose was 60-80%; doses were 10-20 Gy. Follow-up: 12 months-13 years; median, 14 months. Results: Local control (LC) was not improved in 51 margin patients vs. 42 classic RS patients: 1 year: 69.1% and 72.4%. Two-year LC rate: 64% and 54.7%, respectively. Survival: median classic RS: 11.3 months; margin RS, 19 months (p = 0.34) and 1 year, 41.6% and 60.2%, respectively. Margin RS patients had a significantly higher rate of severe parenchymal complications: 19.6% vs. 7.1% (p = 0.02); surgery was necessary in 4 of 51 cases vs. 1 of 42 classic RS cases. Conclusion: No increase of 1- and 2-year LC rate in margin RS or survival and median survival: 11.3 vs. 19 months (NS) 2-mm margin associated with more severe parenchymal complications (p = 0.02).This procedure is therefore not recommended. Late CT images and 1-mm margin as recommended by pathologists, use of three-dimensional magnetic resonance imaging and fuzzy method to calculate volumes may yield better results. Stereotactic hypofractionation requires further studies.

  8. 450mm wafer patterning with jet and flash imprint lithography

    NASA Astrophysics Data System (ADS)

    Thompson, Ecron; Hellebrekers, Paul; Hofemann, Paul; LaBrake, Dwayne L.; Resnick, Douglas J.; Sreenivasan, S. V.

    2013-09-01

    The next step in the evolution of wafer size is 450mm. Any transition in sizing is an enormous task that must account for fabrication space, environmental health and safety concerns, wafer standards, metrology capability, individual process module development and device integration. For 450mm, an aggressive goal of 2018 has been set, with pilot line operation as early as 2016. To address these goals, consortiums have been formed to establish the infrastructure necessary to the transition, with a focus on the development of both process and metrology tools. Central to any process module development, which includes deposition, etch and chemical mechanical polishing is the lithography tool. In order to address the need for early learning and advance process module development, Molecular Imprints Inc. has provided the industry with the first advanced lithography platform, the Imprio® 450, capable of patterning a full 450mm wafer. The Imprio 450 was accepted by Intel at the end of 2012 and is now being used to support the 450mm wafer process development demands as part of a multi-year wafer services contract to facilitate the semiconductor industry's transition to lower cost 450mm wafer production. The Imprio 450 uses a Jet and Flash Imprint Lithography (J-FILTM) process that employs drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for markets including NAND Flash memory, patterned media for hard disk drives and displays. This paper reviews the recent performance of the J-FIL technology (including overlay, throughput and defectivity), mask development improvements provided by Dai Nippon Printing, and the application of the technology to a 450mm lithography platform.

  9. Optical band gap demarcation around 2.15 eV depending on preferred orientation growth in red HgI2 films

    NASA Astrophysics Data System (ADS)

    Tyagi, Pankaj

    2017-04-01

    Thermally evaporated stoichiometric films of red HgI2 show preferred orientation growth with either (102) or (002) orientation. The as grown films shows a change from one preferred orientation to another depending on their thickness, open-air heat-treatment and in-situ heat treatment of films. The in-situ heat-treatment of thermally evaporated stoichiometric films of red HgI2 with preferred growth of (102) orientation shows a gradual linear decrease in film thickness with in-situ heat-treatment temperature. On in-situ heat-treatment above 80 °C, it is found that HgI2 films become thinner than 900 nm, which are otherwise difficult to grow due to high vapor pressure of HgI2. For these films the preferred orientation also changed from (102) to (002). The optical band gap (Eg) also found to increase linearly with in-situ heat-treatment temperature. It is interesting to note that in-situ heat-treated films having (002) orientation had higher values of optical band gap than (102) orientation films. On combining these results with those of as grown and open-air heat-treated red HgI2 films reported in the literature, it is evident that there exists an optical band gap demarcation around 2.15 eV for red HgI2 thin films depending on their preferred orientation growth. Films with (102) orientation are found to have optical band gap less than 2.15 eV and those with (002) orientation are found to have optical band gap more than 2.15 eV. This is irrespective of the physical mean of obtaining the preferred orientation. The preferred orientation can be achieved by either physical means such as growing films with higher thickness, heat-treating them for short duration in open air or heat-treating them in-situ.

  10. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues.

    PubMed

    Baldi, Franco; Gallo, Michele; Marchetto, Davide; Faleri, Claudia; Maida, Isabel; Fani, Renato

    2013-08-01

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5mgl(-1) HgCl2 and incubated at 30°C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills.

  11. Novel Processing of 81-mm Cu Shaped Charge Liners

    SciTech Connect

    Schwartz, A; Korzekwa, D

    2002-01-16

    A seven-step procedure was developed for producing shaped charge liner blanks by back extrusion at liquid nitrogen temperatures. Starting with a 38.1-mm diameter, 101.6-mm long cylinder at 77K, three forging steps with a flat-top die are required to produce the solid cone while maintaining low temperature. The solid cone is forged in four individual back extrusions at 77K to produce the rough liner blank. This procedure is capable of being run in batch processes to improve the time efficiency.

  12. Thomson scattering on high pressure Hg discharge lamps

    NASA Astrophysics Data System (ADS)

    Zhu, X.; de Vries, N.; Kieft, E. R.; van der Mullen, J. J. A. M.; Haverlag, M.

    2005-06-01

    Thomson scattering (TS) experiments have been performed on high-pressure Hg discharge lamps. These lamps were filled with different amounts of Hg (15, 30, 50 and 70 mg) and were operating at different powers (150, 200 and 240 W) with a square-wave ballast. As in the previous studies (Zhu X et al 2004 J. Phys. D: Appl. Phys. 37 736-43) a triple grating spectrograph was used to suppress the false stray light and Rayleigh scattered photons. This set-up had to be modified for this special application. The collective TS spectra have been fitted using both a calibration using Raman scattering and a form fitting procedure. It was found that the electron temperature fluctuates around a certain value that seems rather constant in the central region. The value of electron temperature (Te) varies between 5500 and 7600 K in the central region (r <= 0.3 R). The spatial-averaged Te value increases with the lamp power. The electron density was found to be of the order of 1021 m-3 which is high at the centre and decreases as r increases. The ne value also increases with the lamp power. Moreover the results of TS are compared with those from x-ray absorption measurement. The comparison shows that the plasmas in such lamps are not in local thermal equilibrium in the sense that T_e\

  13. New features of superdeformed bands in {sup 194}Hg

    SciTech Connect

    Janssens, R.V.F.; Ahmad, I.; Carpenter, M.P.

    1995-08-01

    A striking difference between superdeformed (SD) nuclei near A = 190 and those in the other regions is the behavior of the dynamic moment of inertia (lm) with the rotational frequency h{omega}. While the (lm) patterns of the SD bands near A = 130 and A = 150 show pronounced variations, the majority of the SD bands near A = 190 display the same large, smooth increase of (lm) within the frequency range 0.15 < {h_bar}{omega} < 0.40 MeV. Current interpretations of this rise of (lm) within mean field theories invoke the gradual alignment of quasiparticles occupying high-N intruder orbitals in the presence of pair correlations. It is a direct consequence of these interpretations that, after the quasiparticle alignments take place, (lm) will exhibit a downturn with increasing {h_bar}{omega} toward the rigid-body value. Up to now, no downturn in (lm) for the SD bands in the A = 190 mass region was observed, raising some doubt as to our understanding of pair correlations and alignment effects at these large deformations. An experiment was carried out at the 88-Inch Cyclotron facility of the Lawrence Berkeley Laboratory where excited states in {sup 194}Hg were populated with the reaction {sup 150}Nd({sup 48}Ca,4n) {sup 194}Hg at a beam energy of 206 MeV. The gamma rays emitted in the reaction were detected with the Gammasphere detector array (32 detectors for this experiment).

  14. The Abundance and Isotopic Composition of Hg in Extraterrestrial Materials

    NASA Technical Reports Server (NTRS)

    Blum, J. D.; Klaue, Bjorn

    2005-01-01

    During the three year grant period we made excellent progress in our study of the abundances and isotopic compositions of Hg and other volatile trace elements in extraterrestrial materials. At the time the grant started, our collaborating PI, Dante Lauretts, was a postdoctoral research associate working with Peter Buseck at Arizona State University. The work on chondritic Hg was done in collaboration with Dante Lauretta and Peter Buseck and this study was published in Lauretta et a1 (2001a). In July, 2001 Dante Lauretta accepted a position as an Assistant Professor in the Lunar and Planetary Laboratory at the University of Arizona. His funding was transferred and this grant has supported much of his research activities during his first two years at the U of A. Several other papers are in preparation and will be published soon. We presented papers on this topic at Goldschmidt Conferences, the Lunar and Planetary Science Conferences, and the Annual Meetings of the Meteoritical Society. The work done under this grant has spurred several new directions of inquiry, which we are still pursuing. Included in this paper are the studies of bulk abundances and isotopic compositions of metreoritic Mercury, and the development of a thermal analysis ICP-MS technique applied to thermally liable elements.

  15. Contrasting Food Web Factor and Body Size Relationships with Hg and Se Concentrations in Marine Biota

    PubMed Central

    Karimi, Roxanne; Frisk, Michael; Fisher, Nicholas S.

    2013-01-01

    Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by δ15N) and degree of pelagic feeding (measured by δ13C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans. PMID:24019976

  16. Biosorption of Hg(II) onto goethite with extracellular polymeric substances.

    PubMed

    Song, Wenjuan; Pan, Xiangliang; Mu, Shuyong; Zhang, Daoyong; Yang, Xue; Lee, Duu-Jong

    2014-05-01

    This study characterized the interactions of goethite, EPS from cyanobacterium Chroococcus sp. and Hg(II) using excitation emission matrix (EEM) spectra and adsorption isotherms. Three protein-like fluorescence peaks were noted to quench in the presence of Hg(II). The estimated conditional stability constant (logKa) and the binding constant (logKb) of the studied EPS-Hg(II) systems ranged 3.84-4.24 and 6.99-7.69, respectively. The proteins in EPS formed stable complex with Hg(II). The presence of proteins of Chroococcus sp. enhanced the adsorption capacity of Hg(II) on goethite; therefore, the goethite-EPS soil is a larger Hg(II) sink than goethite alone soil. Biosorption significantly affects the mobility of Hg(II) in goethite soils.

  17. No increased risk of psychological/behavioral disorders in siblings of women with hyperemesis gravidarum (HG) unless their mother had HG.

    PubMed

    Mullin, P M; Bray, A; Vu, V; Schoenberg-Paik, F; MacGibbon, K; Romero, R; Goodwin, T M; Fejzo, M S

    2012-10-01

    Hyperemesis gravidarum (HG), severe nausea and vomiting of pregnancy, is characterized by prolonged maternal stress, undernutrition and dehydration. Maternal stress and malnutrition of pregnancy are linked to poor neonatal outcome and associated with poor adult health, and we recently showed that in utero exposure to HG may lead to increased risks of psychological and behavioral disorders in the offspring. In addition, we have shown familial aggregation of HG, which is strong evidence for a genetic component to the disease. In this study, we compare the rates of psychological and behavioral disorders in 172 adults with and 101 adults without a sibling with HG. The rate of emotional/behavioral disorders is identical (15%) in both groups. The results suggest that the etiology of HG is not likely to include genetic factors associated with emotional and behavioral disorders. In addition, this study provides evidence that the increased incidence of psychological/behavioral disorders among offspring of women with HG is attributable to the HG pregnancy itself, rather than to confounding genetic factors linked to HG.

  18. Spatial distribution and accumulation of Hg in soil surrounding a Zn/Pb smelter.

    PubMed

    Wu, Qingru; Wang, Shuxiao; Wang, Long; Liu, Fang; Lin, Che-Jen; Zhang, Lei; Wang, Fengyang

    2014-10-15

    Nonferrous metal smelting is an important atmospheric mercury (Hg) emission source that has significant local and global impacts. To quantify the impact of Hg emission from non-ferrous metal smelter on the surrounding soil, an integrated model parameterizing the processes of smelter emission, air dispersion, atmospheric deposition and Hg accumulation in soil was developed. The concentrations of gaseous elemental Hg (GEM) around the smelter and the spatial distribution of Hg in the surrounding soil were measured and compared with the model results. Atmospheric deposition of Hg emitted from the smelter was identified as the main source of Hg accumulation in the surrounding soil. From 1960 to 2011, the smelter emitted approximately 105 t of Hg into the atmosphere, of which 15 t deposited locally and resulted in an increase of Hg concentration in soil from 0.12 to 1.77 mg kg(-1). A detailed examination of wind rose and model data suggested that the area within 1.0-1.5 km northwest and southeast of the smelter was most severely impacted. It was estimated that the smelter operation from 1969 to 1990, when large scale emission controls were not implemented, resulted in 6450 μg m(-2)yr(-1) of Hg net deposition and a model simulated increase of 0.40 mg kg(-1) of Hg accumulation in the soil. During the period from 1991 to 2011, atmospheric Hg emission from the smelter alone increased the average concentration in soil from 0.41 mg kg(-1) to 0.45 mg kg(-1). In the past 50 years, over 86% of Hg emitted from this smelter went into the global pool, indicating the importance of controlling Hg emissions from non-ferrous metal smelters.

  19. A rapid electrochemical procedure for the detection of Hg(0) produced by mercuric-reductase: application for monitoring Hg-resistant bacteria activity.

    PubMed

    Battistel, Dario; Baldi, Franco; Marchetto, Davide; Gallo, Michele; Daniele, Salvatore

    2012-10-02

    In this work, gold microelectrodes are employed as traps for the detection of volatilized metallic mercury produced by mercuric reductase (MerA) extracted from an Hg-resistant Pseudomonas putida strain FB1. The enzymatic reduction of Hg (II) to Hg (0) was induced by NADPH cofactor added to the samples. The amount of Hg(0) accumulated on the gold microelectrode surface was determined by anodic stripping voltammetry (ASV) after transferring the gold microelectrode in an aqueous solution containing 0.1 M HNO(3) + 1 M KNO(3). Electrochemical measurements were combined with spectrofluorometric assays of NADPH consumption to derive an analytical expression for the detection of a relative MerA activity of different samples with respect to that of P. putida. The method developed here was employed for the rapid determination of MerA produced by bacteria harbored in soft tissues of clams (Ruditapes philippinarum), collected in high Hg polluted sediments of Northern Adriatic Sea in Italy.

  20. Experimental and theoretical investigation of the electronic structure and optical properties of TlHgCl3 single crystal

    NASA Astrophysics Data System (ADS)

    Reshak, A. H.; Kityk, I. V.; Alahmed, Z. A.; Levkovets, S.; Fedorchuk, A. O.; Myronchuk, G.; Plucinski, K. J.; Kamarudin, H.; Auluck, S.

    2015-09-01

    We have synthesized single crystals of TlHgCl3, which posses an orthorhombic symmetry, space group Pnma, with lattice constants a = 9.1601(4) Å, b = 4.3548(2) Å and c = 14.0396(5) Å. The measurements of the optical absorption of TlHgCl3 are performed on parallel-plate samples with polished optical quality surfaces of d = 0.03 mm. The band gap is estimated to be 2.74 eV from the position of fundamental absorption edge at α = 200 cm-1. We have used our measured crystallographic data of TlHgCl3 as input data for calculating the electronic band structure, density of states, electronic charge density and the optical properties. The all-electron full potential linearized augmented plane wave plus local orbital (FP-L(APW + lo)) method is used. Calculations are performed with three types of exchange correlations; local density approximation (LDA), general gradient approximation (PBE-GGA) and the recently modified Becke-Johnson potential (mBJ). The PBE-GGA is used to optimize the atomic positions by minimization of the forces (1 mRy/au) acting on the atoms. The obtained values of the band gap from various exchange correlations are 2.39 eV (LDA), 2.55 eV (PBE-GGA) and 2.69 eV (mBJ). It is clear that mBJ succeeded by a large amount in bringing the calculated energy gap closer to the experimental one. The calculated electronic band structure exhibits that the conduction band minimum and the valence band maximum are located at Z point of the BZ, resulting in a direct band gap. The calculated density of states provides information about the hybridization between the states and the bonding nature. The electronic charge density show that Hg and Cl atoms form partial ionic/covalent bonding between Cl-Hg-Cl. Furthermore, for a deep insight into the electronic structure we have investigated the optical properties.

  1. Guide to Free-Loan Sports Films (16mm).

    ERIC Educational Resources Information Center

    1974

    This catalog provides information on free 16 mm films dealing with a wide variety of individual and team sports, such as football, golf, water sports, snow sports, racing, and baseball, as well as on general sports competition and safety. Unless otherwise noted, the films are in color and with sound. Titles are listed alphabetically under their…

  2. Propellant Residues Deposition from Firing of 40-mm Grenades

    DTIC Science & Technology

    2010-09-01

    the snow surface downrange of the firing positions in three sampling units on each pad. Samples were analyzed and results compo- sited to derive an...Processing and Analysis ..................................................................... 10 3.1 Snow samples...mm howitzers, propel- lant residues containing DNT were collected from the snow -covered area in front of one of the guns (Walsh, M.E. et al. 2004

  3. Downslope windstorm in Iceland - WRF/MM5 model comparison

    NASA Astrophysics Data System (ADS)

    Rögnvaldsson, Ó.; Bao, J.-W.; Ágústsson, H.; Ólafsson, H.

    2011-01-01

    A severe windstorm downstream of Mt. Öræfajökull in Southeast Iceland is simulated on a grid of 1 km horizontal resolution by using the PSU/NCAR MM5 model and the Advanced Research WRF model. Both models are run with a new, two equation planetary boundary layer (PBL) scheme as well as the ETA/MYJ PBL schemes. The storm is also simulated using six different micro-physics schemes in combination with the MYJ PBL scheme in WRF, as well as one "dry" run. Output from a 3 km MM5 domain simulation is used to initialise and drive both the 1 km MM5 and WRF simulations. Both models capture gravity-wave breaking over Mt. Öræfajökull, while the vertical structure of the lee wave differs between the two models and the PBL schemes. The WRF simulated downslope winds, using both the MYJ and 2EQ PBL schemes, are in good agreement with the strength of the observed downslope windstorm. The MM5 simulated surface winds, with the new two equation model, are in better agreement to observations than when using the ETA scheme. Micro-physics processes are shown to play an important role in the formation of downslope windstorms and a correctly simulated moisture distribution is decisive for a successful windstorm prediction. Of the micro-physics schemes tested, only the Thompson scheme captures the downslope windstorm.

  4. Advisory List of Instructional Media--16MM Films.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Educational Media.

    These two advisory lists include information on 16mm films appropriate for the K-12 instructional program. In both bibliographies films are listed in the following categories: communication skills; guidance; health, physical education, safety, and sports; science; and social studies. The list for the 1982-1983 school year also includes categories…

  5. Guide to Films (16 mm) About Ecology, Adaptation and Pollution.

    ERIC Educational Resources Information Center

    1971

    Synopses of 350 films (16 mm.) on ecology, adaptation of plants and animals to their environment, and environmental pollution are listed alphabetically by title in this guide. It specifies whether the film is black-and-white or color, its running time, and its source. An abbreviated subject index and a directory of sources are also provided. The…

  6. IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION IN MM5

    EPA Science Inventory

    The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations (~1-km horizontal grid spacing). The UCP accounts for drag ...

  7. LIGA-fabricated compact mm-wave linear accelerator cavities.

    SciTech Connect

    Song, J.J.; Bajikar, S.S.; DeCarlo, F.; Kang, Y.W.; Kustom, R.L.; Mancini, D.C.; Nassiri, A.; Lai, B.; Feinerman, A.D.; White, V.

    1998-03-23

    Millimeter-wave rf cavities for use in linear accelerators, free-electron lasers, and mm-wave undulatory are under development at Argonne National Laboratory. Typical cavity dimensions are in the 1000 mm range, and the overall length of the accelerator structure, which consists of 30-100 cavities, is about 50-100 mm. An accuracy of 0.2% in the cavity dimensions is necessary in order to achieve a high Q-factor of the cavity. To achieve this these structures are being fabricated using deep X-ray lithography, electroforming, and assembly (LIGA). The first prototype cavity structures are designed for 108 GHz and 2p/3-mode operation. Input and output couplers are integrated with the cavity structures. The cavities are fabricated on copper substrates by electroforming copper into 1-mm-thick PMMA resists patterned by deep x-ray lithography and polishing the copper down to the desired thickness. These are fabricated separately and subsequently assembled with precision spacing and alignment using microspheres, optical fibers, or microfabricated spacers/alignment pieces. Details of the fabrication process, alignment, and assembly work are presented in here.

  8. Bell & Howell Introduces an 8mm Cartridge Concept

    ERIC Educational Resources Information Center

    Educ Screen Audiovisual Guide, 1970

    1970-01-01

    "Bell & Howell has developed a highly versatile cartidge projector system for cine and super 8mm formats. Because Bell & Howell believes that standardization is an important factor in the development of a cartridge system, it has built in a flexibility which will allow this standardization. (Author)

  9. Mercury methylation in paddy soil: source and distribution of mercury species at a Hg mining area, Guizhou Province, China

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Anderson, Christopher W. N.; Qiu, Guangle; Meng, Bo; Wang, Dingyong; Feng, Xinbin

    2016-04-01

    Rice paddy plantation is the dominant agricultural land use throughout Asia. Rice paddy fields have been identified as important sites for methylmercury (MeHg) production in the terrestrial ecosystem and a primary pathway of MeHg exposure to humans in mercury (Hg) mining areas. We compared the source and distribution of Hg species in different compartments of the rice paddy during a complete rice-growing season at two different typical Hg-contaminated mining sites in Guizhou province, China: an abandoned site with a high Hg concentration in soil but a low concentration in the atmosphere and a current-day artisanal site with a low concentration in soil but a high concentration in the atmosphere. Our results showed that the flux of new Hg to the ecosystem from irrigation and atmospheric deposition was insignificant relative to the pool of old Hg in soil; the dominant source of MeHg to paddy soil is in situ methylation of inorganic Hg (IHg). Elevated MeHg concentrations and the high proportion of Hg as MeHg in paddy water and the surface soil layer at the artisanal site demonstrated active Hg methylation at this site only. We propose that the in situ production of MeHg in paddy water and surface soil is dependent on elevated Hg in the atmosphere and the consequential deposition of new Hg into a low-pH anoxic geochemical system. The absence of depth-dependent variability in the MeHg concentration in soil cores collected from the abandoned Hg mining site, consistent with the low concentration of Hg in the atmosphere and high pH of the paddy water and irrigation water, suggested that net production of MeHg at this site was limited. We propose that the concentration of Hg in ambient air is an indicator for the risk of MeHg accumulation in paddy rice.

  10. A State-of-the-Science Hg Redox Mechanism for Atmospheric Models: Constraints from Observations and Global Implications

    NASA Astrophysics Data System (ADS)

    Horowitz, H.; Jacob, D. J.; Amos, H. M.; Streets, D. G.; Zhang, Y.; Dibble, T. S.; Slemr, F.; Sunderland, E. M.

    2015-12-01

    Mercury (Hg) in the atmosphere cycles between two redox forms, Hg0 and HgII. Hg0 has a lifetime of ~1 year allowing near-global transport, while HgII is efficiently removed by deposition within weeks. Understanding atmospheric Hg redox chemistry is critical to determining the patterns of deposition to the surface, where Hg can be transformed to the bioaccumulative neurotoxin, methylmercury. We present a state-of-the-science redox mechanism for use in atmospheric models, with new theoretical data, which we implement in a global 3-D chemical transport model (GEOS-Chem). We evaluate our simulation against atmospheric observations and examine implications for Hg deposition. Modeled HgII wet deposition depends on the oxidation of anthropogenic, ocean, and soil Hg0 emissions and the reduction of emitted anthropogenic HgII. We present a new global anthropogenic atmospheric Hg emissions inventory for 1990 - 2010 with improved speciation of power plant emissions and regional commercial Hg emissions. The seasonal cycle of ocean evasion is also critical to atmospheric Hg variability. We present an advance in our ability to model atmosphere-ocean exchange of Hg, through more realistic ocean circulation from the 3-D MITgcm. Our results suggest Br is the dominant oxidant in the stratosphere, consistent with constraints from aircraft observations of the Hg gradient with depth into the stratosphere. The proposed redox mechanism leads to increased HgII deposition to the Tropics, with implications for tropical surface ocean enrichment, and decreased deposition to the Southern Ocean. Within the uncertainty of Hg0 oxidation rates, we find atmospheric HgII reduction is still needed. We find changes in speciated Hg emissions due to emissions controls can explain recent observed regional trends in atmospheric Hg. These have shifted power plant impacts to relatively more global than local Hg deposition. Coupling to the more realistic 3-D ocean model improves simulated atmospheric Hg

  11. Phycobiliproteins or C-phycocyanin of Arthrospira (Spirulina) maxima protect against HgCl(2)-caused oxidative stress and renal damage.

    PubMed

    Rodríguez-Sánchez, R; Ortiz-Butrón, R; Blas-Valdivia, V; Hernández-García, A; Cano-Europa, E

    2012-12-15

    Our objective was to determine if the phycobiliproteins of Arthrospira (Spirulina) maxima protect renal cells against mercury-caused oxidative stress and cellular damage in the kidney. We used 40 male mice that were assigned into eight groups: (1) a control group that received 100mM phosphate buffer (PB) ig and 0.9% saline ip, (2) PB+HgCl(2) (5mg/kg ip), (3) PB plus phycobiliproteins (100mg/kg ig), (4) PB plus C-phycocyanin (100mg/kg ig), and four groups receiving HgCl(2)+phycobiliproteins or C-phycocyanin (50, and 100mg/kg ig). The left kidneys were used to determine lipid peroxidation, quantification of reactive oxygen species, and reduced glutathione and oxidised content. The right kidneys were processed for histology. The HgCl(2) caused oxidative stress and cellular damage. All doses of phycobiliproteins or C-phycocyanin prevented enhancement of oxidative markers and they protected against HgCl(2)-caused cellular damage.

  12. Bioaccumulation of As, Cd, Cr, Hg(II), and MeHg in killifish (Fundulus heteroclitus) from amphipod and worm prey.

    PubMed

    Dutton, Jessica; Fisher, Nicholas S

    2011-08-15

    Elevated metal levels in fish are a concern for the fish themselves, their predators, and possibly humans who consume contaminated seafood. Metal bioaccumulation models often rely on assimilation efficiencies (AEs) of ingested metals and loss rate constants after dietary exposure (k(ef)s). These models can be used to better understand processes regulating metal accumulation and can be used to make site-specific predictions of metal concentrations in animal tissues. Fish often consume a varied diet, and prey choice can influence these two parameters. We investigated the trophic transfer of As, Cd, Cr, Hg(II), and methylmercury (MeHg) from a benthic amphipod (Leptocheirus plumulosus) and an oligochaete (Lumbriculus variegatus) to killifish (Fundulus heteroclitus) using gamma-emitting radioisotopes. Except for MeHg, AEs varied between prey type. AEs were highest for MeHg (92%) and lowest for Cd (2.9-4.5%) and Cr (0.2-4%). Hg(II) showed the largest AE difference between prey type (14% amphipods, 24% worms). For Cd and Hg(II) k(ef)s were higher after consuming amphipods than consuming worms. Tissue distribution data shows that Cd and Hg(II) were mainly associated with the intestine, whereas As and MeHg were transported throughout the body. Calculated trophic transfer factors (TTFs) suggest that MeHg is likely to biomagnify at this trophic step at all ingestion rates, whereas As, Cd, Cr, and Hg(II) will not. Data collected in this study and others indicate that using one prey item to calculate AE and k(ef) could lead to an over- or underestimation of these parameters.

  13. Asteroid taxonomy and the H,G_{12} magnitude system

    NASA Astrophysics Data System (ADS)

    Oszkiewicz, D.; Bowell, E.; Wasserman, L.; Muinonen, K.; Penttilä, A.

    2014-07-01

    We review the asteroid magnitude systems. The conventionally used H,G system (approved by the IAU in 1985) was recently replaced by the H,G_{12} and H,G_1,G_2 systems (approved by the IAU in 2012). The new phase curves were already applied to a large quantity of photometric data (Oszkiewicz et al, 2011). In particular, absolute magnitudes and slope parameters were computed for about half a million asteroids and are publicly available through the Planetary Research Group (University of Helsinki) websites. Several correlations of the shape of the phase curves with asteroid physical parameters were also explored. In general, the steepness of a phase curve relates to the physical properties of an asteroid's surface such as for example composition, porosity, packing density, roughness, and grain size distribution. However, most of those cannot be studied with the currently available data. Some conclusions regarding links to albedo and taxonomy can still be made. First, the G_1 and G_2 parameters correlate with albedo. Generally, the higher the albedo the lower and higher are the G_1 and G_2 parameters, respectively. Second, the G_{12} parameter distributions for the different asteroid taxonomic complexes are statistically different. For example, the C-complex asteroids tend to have high G_{12}'s, S-complex asteroids low G_{12}'s, and objects from the X-complex lean towards average values (Oszkiewicz et al. 2012). Additionally, asteroid families with a few exceptions show homogeneity of the G_{12} parameter (Figure). This is yet another confirmation of homogeneity of asteroid families and therefore the overall tendency to retain the same physical properties across family members. We study the usability of the G_{12} parameter in topics such as breaking the X-complex degeneracy and taxonomical classification. In particular, we combine the G_{12}'s with the Sloan Digital Sky Survey (SDSS) and the Wide-Field Infrared Survey Explorer (WISE) data (Oszkiewicz et al. 2014) to

  14. Dose and Hg species determine the T-helper cell activation in murine autoimmunity.

    PubMed

    Havarinasab, Said; Björn, Erik; Ekstrand, Jimmy; Hultman, Per

    2007-01-05

    Inorganic mercury (mercuric chloride--HgCl(2)) induces in mice an autoimmune syndrome (HgIA) with T cell-dependent polyclonal B cell activation and hypergammaglobulinemia, dose- and H-2-dependent production of autoantibodies targeting the 34 kDa nucleolar protein fibrillarin (AFA), and systemic immune-complex deposits. The organic mercury species methylmercury (MeHg) and ethylmercury (EtHg--in the form of thimerosal) induce AFA, while the other manifestations of HgIA seen after treatment with HgCl(2) are present to varying extent. Since these organic Hg species are converted to the autoimmunogen Hg(2+) in the body, their primary autoimmunogen potential is uncertain and the subject of this study. A moderate dose of HgCl(2) (8 mg/L drinking water--internal dose 148 micro gHg/kg body weight [bw]/day) caused the fastest AFA response, while the induction was delayed after higher (25 mg/L) and lower (1.5 and 3 mg/L) doses. The lowest dose of HgCl(2) inducing AFA was 1.5 mg/L drinking water which corresponded to a renal Hg(2+) concentration of 0.53 micro g/g. Using a dose of 8 mg HgCl(2)/L this threshold concentration was reached within 24 h, and a consistent AFA response developed after 8-10 days. The time lag for the immunological part of the reaction leading to a consistent AFA response was therefore 7-9 days. A dose of thimerosal close to the threshold dose for induction of AFA (2 mg/L drinking water--internal dose 118 micro gHg/kg bw per day), caused a renal Hg(2+) concentration of 1.8 micro g/g. The autoimmunogen effect of EtHg might therefore be entirely due to Hg(2+) formed from EtHg in the body. The effect of organic and inorganic Hg species on T-helper type 1 and type 2 cells during induction of AFA was assessed as the presence and titre of AFA of the IgG1 and IgG2a isotype, respectively. EtHg induced a persistent Th1-skewed response irrespectively of the dose and time used. A low daily dose of HgCl(2) (1.5-3 mg/L) caused a Th1-skewed AFA response, while a

  15. Hg Isotopes Reveal Importance of In-Stream Processing and Legacy Inputs in East Fork Poplar Creek, Oak Ridge, Tennessee, USA.

    NASA Astrophysics Data System (ADS)

    Demers, J. D.; Blum, J. D.; Brooks, S. C.; Donovan, P. M.; Gu, B.; Riscassi, A.

    2015-12-01

    Understanding how mercury (Hg) contaminated ecosystems will recover as atmospheric emissions and industrial point source discharges are controlled has become a driving motivation of mercury research. Key to predicting recovery of mercury contaminated ecosystems is an understanding of the mobilization of legacy Hg sources, and the subsequent bioavailability and biogeochemical cycling of mobilized Hg within aquatic ecosystems. Herein, we utilize natural abundance stable Hg isotope techniques to place new constraints on mercury sources, transport, and transformations along the flow path of East Fork Poplar Creek (EFPC), Oak Ridge, Tennessee. The isotopic composition of mercury in stream water and suspended sediment along the flow path suggest that: (1) physical processes such as dilution and sedimentation cannot fully explain decreases in total mercury concentrations along the flow path and that in-stream processes may be more important than previously realized; (2) in-stream processes include photochemical transformations (~20%), but microbial reduction is likely more dominant (~80%); and (3) additional sources of mercury inputs to EFPC at base-flow may predominantly arise from the hyporheic zone during the growing season, with adjacent riparian wetlands and non-point-source impacted tributaries increasing in importance during the dormant season when the stream channel is more hydrologically connected to the watershed.

  16. Studies on a novel mask technique with high selectivity and aspect-ratio patterns for HgCdTe trenches ICP etching

    NASA Astrophysics Data System (ADS)

    Ye, Z. H.; Hu, W. D.; Li, Y.; Huang, J.; Yin, W. T.; Lin, C.; Hu, X. N.; Ding, R. J.; Chen, X. S.; Lu, W.; He, L.

    2012-06-01

    A novel mask technique, combining high selectivity silicon dioxide patterns over high aspect-ratio photoresist (PR) patterns has been exploited to perform mesa etching for device delineation and electrical isolation of HgCdTe third-generation infrared focal plane arrays (IRFPAs). High-density silicon dioxide film covering high aspect-ratio PR patterns was deposited at the temperature of 80°C and silicon dioxide film patterns over high aspect-ratio PR patterns of HgCdTe etching samples was developed by standard photolithography and wet chemical etch. Scanning electron microscopy (SEM) shows that the surfaces of inductively coupled plasma (ICP) etched samples are quite clean and smooth. The etching selectivity between the novel mask and HgCdTe of the samples is increased to above 32: 1 while the side-wall impact of etching plasma is suppressed by the high aspect ratio patterns. These results show that the combined patterning of silicon dioxide film and thick PR film is a readily available and promising masking technique for HgCdTe mesa etching.

  17. 47 CFR 80.131 - Radioprinter operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Radioprinter operations. 80.131 Section 80.131... Radioprinter operations. Radioprinter operations provide a relatively low cost system of record communications... radioprinter operations....

  18. 40 CFR 142.80 - Review procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that Implement Criteria Under Which Filtration Is Required § 142.80 Review procedures. (a) The Administrator...

  19. 40 CFR 142.80 - Review procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that Implement Criteria Under Which Filtration Is Required § 142.80 Review procedures. (a) The Administrator...

  20. 40 CFR 142.80 - Review procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that Implement Criteria Under Which Filtration Is Required § 142.80 Review procedures. (a) The Administrator...

  1. 40 CFR 142.80 - Review procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that Implement Criteria Under Which Filtration Is Required § 142.80 Review procedures. (a) The Administrator...

  2. 40 CFR 142.80 - Review procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....80 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS IMPLEMENTATION Administrator's Review of State Decisions that Implement Criteria Under Which Filtration Is Required § 142.80 Review procedures. (a) The Administrator...

  3. Long Noncoding RNA MIR4697HG Promotes Cell Growth and Metastasis in Human Ovarian Cancer

    PubMed Central

    Zhang, Li-qian; Yang, Su-qing; Wang, Ying; Fang, Qiao; Chen, Xian-jun; Lu, Hong-sheng

    2017-01-01

    Ovarian cancer is one of the three most common gynecological malignant tumors worldwide. The prognosis of patients suffering from this malignancy remains poor because of limited therapeutic strategies. Herein, we investigated the role of a long noncoding RNA named MIR4697 host gene (MIR4697HG) in the cell growth and metastasis of ovarian cancer. Results showed that the transcriptional level of MIR4697HG in cancerous tissues increased twofold compared with that in adjacent noncancerous tissues. MIR4697HG was differentially expressed in ovarian cancer cell lines, with the highest levels in OVCAR3 and SKOV3 cells. MIR4697HG knockdown by specific shRNA significantly inhibited cell proliferation and colony formation in both OVCAR3 and SKOC3 cells. Consistently, in a xenograft model of ovarian cancer, MIR4697HG depletion also significantly restricted tumor volumes and weights. Furthermore, MIR4697HG knockdown inhibited cell migration and invasion capacities. Invasion ability was inhibited by 58% in SKOV3 cells and 40% in OVCAR3 cells, and migration ability was inhibited by 73% in SKOV3 cells and 62% in OVCAR3 cells after MIR4697HG knockdown. MIR4697HG knockdown also caused a decrease in matrix metalloprotease-9, phosphorylated ERK, and phosphorylated AKT. These data suggested that MIR4697HG promoted ovarian cancer growth and metastasis. The aggressive role of MIR4697HG in ovarian cancer may be related to the ERK and AKT signaling pathways. PMID:28168162

  4. Lupinus albus plants acquire mercury tolerance when inoculated with an Hg-resistant Bradyrhizobium strain.

    PubMed

    Quiñones, Miguel A; Ruiz-Díez, Beatriz; Fajardo, Susana; López-Berdonces, Miguel A; Higueras, Pablo L; Fernández-Pascual, Mercedes

    2013-12-01

    One strain of Bradyrhizobium canariense (L-7AH) was selected for its metal-resistance and ability to nodulate white lupin (Lupinus albus L.) plants, from a collection of rhizobial strains previously created from soils of the Almadén mining district (Spain) with varying levels of Hg contamination. Plants were inoculated with either strain L-7AH (Hg-tolerant) or L-3 (Hg-sensitive, used as control), and watered with nutrient solutions supplemented with various concentrations (0-200 μM) of HgCl2 in a growth chamber. L. albus inoculated with L-7AH were able to nodulate even at the highest concentration of Hg while those inoculated with L-3 had virtually no nodules at Hg concentrations above 25 μM. Plants inoculated with L-7AH, but not those with the control strain, were able to accumulate large amounts of Hg in their roots and nodules. Nodulation with L-7AH allowed plants to maintain constant levels of both chlorophylls and carotenoids in their leaves and a high photosynthetic efficiency, whereas in those inoculated with L-3 both pigment content and photosynthetic efficiency decreased significantly as Hg concentration increased. Nitrogenase activity of plants nodulated with L-7AH remained fairly constant at all concentrations of Hg used. Results suggest that this symbiotic pair may be used for rhizoremediation of Hg-contaminated soils.

  5. Assessing anthropogenic sources of mercury in soil in Wanshan Hg mining area, Guizhou, China.

    PubMed

    Dai, Zhihui; Feng, Xinbin; Zhang, Chao; Wang, Jingfu; Jiang, Taiming; Xiao, Houjun; Li, Yu; Wang, Xun; Qiu, Guangle

    2013-11-01

    Long-term mining and smelting activities brought a series of environmental issues into soils in Wanshan mercury (Hg) mining area (WMMA), Guizhou, China. Several studies have been published on the concentrations of Hg in local soils, but a comprehensive assessment of the mass of Hg in soil induced by anthropogenic activities, as presented in this paper, has not been previously conducted. Three districts of WMMA were chosen as the study areas. We summarized previous published data and sampled 14 typical soil profiles to analyze the spatial and vertical distributions of Hg in soil in the study areas. The regional geologic background, direct and indirect Hg deposition, and Hg-polluted irrigation water were considered as the main sources of Hg contaminations in local soils. Furthermore, the enrichment factor (EF) method was applied to assess the extent of anthropogenic input of Hg to soil. Titanium (Ti) was chosen to be the reference element to calculate the EF. Generally, the elevated values of EF were observed in the upper soil layers and close to mine wastes. The total budget of Hg in soil contributed from anthropogenic sources was estimated to be 1,227 t in arable soil and 75 t in natural soil. Our data showed that arable soil was the major sink of anthropogenic Hg in the study area.

  6. Photosynthetic pigments and peroxidase activity of Lepidium sativum L. during assisted Hg phytoextraction.

    PubMed

    Smolinska, Beata; Leszczynska, Joanna

    2017-04-06

    The study was conducted to evaluate metabolic answer of Lepidium sativum L. on Hg, compost, and citric acid during assisted phytoextraction. The chlorophyll a and b contents, total carotenoids, and activity of peroxidase were determined in plants exposed to Hg and soil amendments. Hg accumulation in plant shoots was also investigated. The pot experiments were provided in soil artificially contaminated by Hg and/or supplemented with compost and citric acid. Hg concentration in plant shoots and soil substrates was determined by cold vapor atomic absorption spectroscopy (CV-AAS) method after acid mineralization. The plant photosynthetic pigments and peroxidase activity were measured by standard spectrophotometric methods. The study shows that L. sativum L. accumulated Hg in its aerial tissues. An increase in Hg accumulation was noticed when soil was supplemented with compost and citric acid. Increasing Hg concentration in plant shoots was correlated with enhanced activation of peroxidase activity and changes in total carotenoid concentration. Combined use of compost and citric acid also decreased the chlorophyll a and b contents in plant leaves. Presented study reveals that L. sativum L. is capable of tolerating Hg and its use during phytoextraction assisted by combined use of compost and citric acid lead to decreasing soil contamination by Hg.

  7. Archaic introjects and the cosmology of H.G. Wells.

    PubMed

    Parkin, A

    1982-01-01

    The roles of the archaic loving and hating introjects are traced in the early scientific romances and the life work of H.G. Wells. The preambivalent polarization of the early loving introjects of an archaic ego ideal (giving rise to utopian fantasies and, later, to promulgations of a new world state) and the early hostile introjects of an archaic superego (giving rise to fears of death and, later, to fears of cosmic dissolution) is represented in eschatological preoccupations with death, the Last Judgment, heaven and hell. These religious preoccupations are derivatives of wishes for maternal union and bliss on the one hand, and of castration anxiety and fears of personal annihilation on the other. Further transformations of the archaic introjects are traced through an indentification with the role of redeemer, and later, through his scientific studies, to an espousal of T.H. Huxley's teachings of organic evolution and to the development of cosmological themes in his work.

  8. Advances in HgCdTe APDs and LADAR Receivers

    NASA Technical Reports Server (NTRS)

    Bailey, Steven; McKeag, William; Wang, Jinxue; Jack, Michael; Amzajerdian, Farzin

    2010-01-01

    Raytheon is developing NIR sensor chip assemblies (SCAs) for scanning and staring 3D LADAR systems. High sensitivity is obtained by integrating high performance detectors with gain i.e. APDs with very low noise Readout Integrated Circuits. Unique aspects of these designs include: independent acquisition (non-gated) of pulse returns, multiple pulse returns with both time and intensity reported to enable full 3D reconstruction of the image. Recent breakthrough in device design has resulted in HgCdTe APDs operating at 300K with essentially no excess noise to gains in excess of 100, low NEP <1nW and GHz bandwidths and have demonstrated linear mode photon counting. SCAs utilizing these high performance APDs have been integrated and demonstrated excellent spatial and range resolution enabling detailed 3D imagery both at short range and long ranges. In this presentation we will review progress in high resolution scanning, staring and ultra-high sensitivity photon counting LADAR sensors.

  9. Fractional quantum Hall effect in HgTe quantum wells

    NASA Astrophysics Data System (ADS)

    Wang, Jianhui

    2016-02-01

    We study the possibility of fractional quantum Hall effects in HgTe quantum wells using exact diagonalization. Our results show that Laughlin states, the Moore-Read state, and the Read-Rezayi Z3 state can all be supported. However, near the level crossing point (of the single-particle spectrum) the gap can be destroyed by Landau level mixing, and the Moore-Read state and the Read-Rezayi state dominate over their respective competing states only for wide wells. For smaller well widths the Moore-Read state crosses over to the composite fermion Fermi sea, while the Read-Rezayi state loses its dominance over the hierarchy state.

  10. Lifetimes of an excited superdeformed band in {sup 192}Hg

    SciTech Connect

    Ahmad, I.; Blumenthal, D.; Carpenter, M.P.

    1995-08-01

    An excited superdeformed band was identified in {sup 192}Hg and the lifetimes of its levels measured with the Doppler-shift attenuation method from data taken with the Eurogam spectrometer. The band is proposed to be based on the two-quasineutron (v[642]3/2 [512]5/2) configuration, which after a band crossing, becomes the (v[642]3/2 [752]5/2) configuration. The transition quadrupole moment Q{sub t} of the excited band is the same as that of the yrast SD band, within experimental errors. This suggests that the deformation of the SD minimum is robust with respect to quasiparticle excitation, despite the occupation of the deformation-driving v[752]5/2 level (from the j{sub 15/2} shell) after the band crossing.

  11. Viscosity Relaxation in Molten HgZnTe

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Lehoczky, S. L.; Kim, Yeong Woo; Baird, James K.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Rotating cup measurements of the viscosity of the pseudo-binary melt, HgZnTe have shown that the isothermal liquid with zinc mole fraction 0.16 requires tens of hours of equilibration time before a steady viscous state can be achieved. Over this relaxation period, the viscosity at 790 C increases by a factor of two, while the viscosity at 810 C increases by 40%. Noting that the Group VI elements tend to polymerize when molten, we suggest that the viscosity of the melt is enhanced by the slow formation of Te atom chains. To explain the build-up of linear Te n-mers, we propose a scheme, which contains formation reactions with second order kinetics that increase the molecular weight, and decomposition reactions with first order kinetics that inactivate the chains. The resulting rate equations can be solved for the time dependence of each molecular weight fraction. Using these molecular weight fractions, we calculate the time dependence of the average molecular weight. Using the standard semi-empirical relation between polymer average molecular weight and viscosity, we then calculate the viscosity relaxation curve. By curve fitting, we find that the data imply that the rate constant for n-mer formation is much smaller than the rate constant for n-mer deactivation, suggesting that Te atoms only weakly polymerize in molten HgZnTe. The steady state toward which the melt relaxes occurs as the rate of formation of an n-mer becomes exactly balanced by the sum of the rate for its deactivation and the rate for its polymerization to form an (n+1)-mer.

  12. 9 CFR 592.80 - Political activity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Political activity. 592.80 Section 592.80 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG PRODUCTS INSPECTION VOLUNTARY INSPECTION OF EGG PRODUCTS Performance of Services § 592.80...

  13. 40 CFR 80.300 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false 80.300 Section 80.300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Sulfur Abt Program-Baseline Determination § 80.300 ABT Program—Credit Generation...

  14. 9 CFR 592.80 - Political activity.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Political activity. 592.80 Section 592.80 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG PRODUCTS INSPECTION VOLUNTARY INSPECTION OF EGG PRODUCTS Performance of Services § 592.80...

  15. 9 CFR 592.80 - Political activity.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Political activity. 592.80 Section 592.80 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG PRODUCTS INSPECTION VOLUNTARY INSPECTION OF EGG PRODUCTS Performance of Services § 592.80...

  16. 21 CFR 808.80 - New Jersey.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false New Jersey. 808.80 Section 808.80 Food and Drugs... and Local Exemptions § 808.80 New Jersey. (a) The following New Jersey medical device requirements are... them from preemption under section 521(b) of the act: (1) New Jersey Statutes Annotated, section...

  17. 47 CFR 80.1015 - Power supply.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Power supply. 80.1015 Section 80.1015... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1015 Power supply. (a) There must be readily available for use under normal load conditions, a power supply...

  18. 47 CFR 80.215 - Transmitter power.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Transmitter power. 80.215 Section 80.215... MARITIME SERVICES General Technical Standards § 80.215 Transmitter power. (a) Transmitter power shown on the radio station authorization is the maximum power the licensee is authorized to use. Power...

  19. 40 CFR 80.68 - Compliance surveys.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Compliance surveys. 80.68 Section 80...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.68 Compliance surveys. (a)(1) Beginning January 1, 2007, the compliance surveys for NOX emissions performance under this section shall cease to...

  20. 40 CFR 80.68 - Compliance surveys.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Compliance surveys. 80.68 Section 80...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.68 Compliance surveys. (a)(1) Beginning January 1, 2007, the compliance surveys for NOX emissions performance under this section shall cease to...

  1. 40 CFR 80.68 - Compliance surveys.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Compliance surveys. 80.68 Section 80...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.68 Compliance surveys. (a)(1) Beginning January 1, 2007, the compliance surveys for NOX emissions performance under this section shall cease to...

  2. 40 CFR 80.68 - Compliance surveys.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Compliance surveys. 80.68 Section 80...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.68 Compliance surveys. (a)(1) Beginning January 1, 2007, the compliance surveys for NOX emissions performance under this section shall cease to...

  3. 40 CFR 80.68 - Compliance surveys.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Compliance surveys. 80.68 Section 80...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.68 Compliance surveys. (a)(1) Beginning January 1, 2007, the compliance surveys for NOX emissions performance under this section shall cease to...

  4. 21 CFR 808.80 - New Jersey.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false New Jersey. 808.80 Section 808.80 Food and Drugs... and Local Exemptions § 808.80 New Jersey. (a) The following New Jersey medical device requirements are... them from preemption under section 521(b) of the act: (1) New Jersey Statutes Annotated, section...

  5. 21 CFR 808.80 - New Jersey.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false New Jersey. 808.80 Section 808.80 Food and Drugs... and Local Exemptions § 808.80 New Jersey. (a) The following New Jersey medical device requirements are... them from preemption under section 521(b) of the act: (1) New Jersey Statutes Annotated, section...

  6. 21 CFR 808.80 - New Jersey.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false New Jersey. 808.80 Section 808.80 Food and Drugs... and Local Exemptions § 808.80 New Jersey. (a) The following New Jersey medical device requirements are... them from preemption under section 521(b) of the act: (1) New Jersey Statutes Annotated, section...

  7. 47 CFR 80.146 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false 80.146 Section 80.146 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146...

  8. 47 CFR 80.146 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false 80.146 Section 80.146 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146...

  9. 47 CFR 80.146 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false 80.146 Section 80.146 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146...

  10. 47 CFR 80.146 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false 80.146 Section 80.146 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146...

  11. 47 CFR 80.146 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false 80.146 Section 80.146 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Operating Requirements and Procedures Shipboard General Purpose Watches § 80.146...

  12. 21 CFR 80.31 - Certification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Certification. 80.31 Section 80.31 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL COLOR ADDITIVE CERTIFICATION Certification Procedures § 80.31 Certification. (a) If the Commissioner determines, after...

  13. 47 CFR 80.1015 - Power supply.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Power supply. 80.1015 Section 80.1015... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1015 Power supply. (a) There must be readily available for use under normal load conditions, a power supply...

  14. 47 CFR 80.1015 - Power supply.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Power supply. 80.1015 Section 80.1015... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1015 Power supply. (a) There must be readily available for use under normal load conditions, a power supply...

  15. 47 CFR 80.1015 - Power supply.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Power supply. 80.1015 Section 80.1015... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1015 Power supply. (a) There must be readily available for use under normal load conditions, a power supply...

  16. 47 CFR 80.1015 - Power supply.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Power supply. 80.1015 Section 80.1015... MARITIME SERVICES Radiotelephone Installations Required by the Bridge-to-Bridge Act § 80.1015 Power supply. (a) There must be readily available for use under normal load conditions, a power supply...

  17. 47 CFR 80.757 - Topographical data.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Topographical data. 80.757 Section 80.757... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.757 Topographical data. (a... elevations from a 30 second point or better topographic data file such as those available for the...

  18. 47 CFR 80.757 - Topographical data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Topographical data. 80.757 Section 80.757... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.757 Topographical data. (a... elevations from a 30 second point or better topographic data file such as those available for the...

  19. 47 CFR 80.757 - Topographical data.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Topographical data. 80.757 Section 80.757... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.757 Topographical data. (a... elevations from a 30 second point or better topographic data file such as those available for the...

  20. 47 CFR 80.757 - Topographical data.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Topographical data. 80.757 Section 80.757... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.757 Topographical data. (a... elevations from a 30 second point or better topographic data file such as those available for the...