Hydrodynamics and freshwater diversion within Barataria Basin

In order to understand the physical processes in the Barataria estuary, a previously developed two-dimensional, depth-integrated hydrodynamic model is applied to simulate estuarine processes. The equations for conservation of mass and momentum predict specific physical processes when forced by tidal and salinity variations at the open boundaries, wind forcing patterns, precipitation and evaporation over the model domain, and freshwater runoff as point sources. This study is focused on examining the impact of freshwater dispersion from the freshwater sources. Thus, a hydrologic model was developed to estimate runoff. Furthermore grid size was reduced, a new advective code added, and baroclinic effects included. The model was run with and without freshwater diversions from the Mississippi River. When compared to observations the correlation coefficients ( ) of model water levels are larger than 0.9 at all but one station. For the hydrologic calibration, a big flood event was tested. Agreement between observed and model results with runoff is surprisingly good. The observed agreement provides a justification for adopting 100 % coupling between the hydrologic model and hydrodynamic model, at least for this flood event. In terms of water level within the basin, the freshwater diversions seem to affect most of the Barataria Basin system water level within 3 days. Using a Hovmüller diagram, tidal phase speed was estimated within the basin as 16 hours to travel from the mouth of Barataria Bay to the top of the basin, Lac des Allemands. In terms of salinity within the basin, the impact of freshwater diversion reaches Barataria Bay within 5 and 10 days from Naomi and West Pointe à la Hache, respectively, and the Gulf of Mexico 15 to 20 days after freshwater release

Evaporative heat transfer of CO2 in a grooved multi-channel micro-tube

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Recent studies on evaporation of carbon dioxide in micro-channels reported that the heat transfer coefficient decreased drastically with increasing quality. To improve the evaporating heat transfer characteristics a grooved multi-channel micro-tube was suggested in this study, and the evaporating heat transfer characteristics have been experimentally investigated. The multi-channel aluminum tube, which is directly heated by the electricity, has 8 channels with a diameter of 0.8mm and a length of 1.1m. Each channel has eight micro-grooves with the width of 0.2mm and depth of 0.1mm. The heat transfer coefficients were measured in the range of heat fluxes from 12 to 18 kW/m2; mass fluxes 400 – 800 kg/m2s; evaporative temperature 5℃; and qualities from zero to superheated state. The measured values were compared with those in the plain multi-channel micro-tubes with the same diameter. The heat transfer coefficient was found to be increased at low qualities (x < 0.4). At high qualities, the sudden drop of the HTC due to the dry-out phenomena was not improved. In the evaporation process of CO2, the grooves applied to microchannels have a noticeable effect only in low quality regions.cs201

Synthesis and Recognition Properties of Higher Order Tetrathiafulvalene (Ttf) Calix N Pyrroles (N=4-6)

Two new benzoTTF-annulated calix[n]pyrroles (n = 5 and 6) were synthesized via a one-step acid catalyzed condensation reaction and fully characterized via single crystallographic analyses. As compared to the known tetra-TTF annulated calix[4]pyrrole, which is also produced under the conditions of the condensation reaction, the expanded calix[n]pyrroles (n = 5 and 6) are characterized by a larger cavity size and a higher number of TTF units (albeit the same empirical formula). Analysis of the binding isotherms obtained from UV-Vis spectroscopic titrations carried out in CHCl3 in the presence of both anionic (Cl-, Br-, I-, CH3COO-, H2PO4-, and HSO4-) and neutral (1,3,5-trinitrobenzene (TNB) and 2,4,6-trinitrotoluene (TNT)) substrates revealed that as a general rule the calix[6]pyrrole derivative proved to be the most efficient molecular receptor for anions, while the calix[4]pyrrole congener proves most effective for the recognition of TNB and TNT. These findings are rationalized in terms of the number of electron rich TTF subunits and NH hydrogen bond donor groups within the series, as well as an ability to adopt conformations suitable for substrate recognition, and are supported by solid state structural analyses.National Science Foundation CHE 1057904, 0741973Robert A. Welch Foundation F-1018Danish Natural Science Research Council (FNU) 272-08-0047, 11-106744WCU (World Class University) program of Korea R32-2010-10217-0Villum FoundationChemistr

Coastal Land Loss And Hypoxia: The \u27Outwelling\u27 Hypothesis Revisited

It is generally believed that interannual variability in the areal extent of the Gulf of Mexico hypoxia is driven primarily by the magnitude of the Mississippi River freshwater and nutrient fluxes. It has recently been proposed that outwelling of carbon from deteriorating coastal wetlands into the surrounding Gulf of Mexico could be an important mechanism promoting the development of hypoxia. We used a coupled hydrology-hydrodynamics model of the Barataria estuary, a site of massive wetland loss, to calculate the fluxes of nitrogen, chlorophyll a and carbon at the estuary-ocean interface. The hydrology model calculates runoff from rainfall and evaporation data, and then feeds it into the high-resolution (100 m x 100 m grid, 1.3 million elements), two-dimensional depth-integrated hydrodynamic model. Model results show substantial outwelling of total organic carbon (TOC, 110 x 10(6) kg yr(-1)), dissolved organic carbon (DOC, 94.3 x 10(6) kg yr(-1)), particulate organic carbon (POC, 15.7 x 10(6) kg yr(-1)) and chlorophyll a (Chl a, 0.3 x 10(6) kg yr(-1)) from the estuary to the coastal waters and an import of nitrate (N-NO3, 6.9 x 10(6) kg yr(-1)) from the nutrient-rich coastal waters into the estuary. Estuarine fluxes of TOC, DOC, POC, Chl a and N-NO3, account for 2.8%, 2.7%, 3.4%, 7.5% and 1%, respectively, of the annual fluxes carried by the lower Mississippi River. The flux of total nitrogen was not statistically significant. Overall, this study supports the conclusion of the previous modeling study (Das et al 2010 Ecol. Modeling 221 978-85), suggesting that the Barataria estuary supplies a relatively small amount of the carbon consumed in the Gulf\u27s hypoxic zone. Importantly, our results indicate that import of nitrate from the coastal waters and its assimilation within the estuary could account for 38% and 208%, respectively, of the calculated TOC and Chl a exports, demonstrating the pervasive control of the Mississippi River on the productivity of this shelf

Guidewire-catheter induced hydrodissection to assist radiofrequency ablation for subcapsular hepatocellular carcinoma with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion

PURPOSEWe aimed to evaluate the usefulness of guidewire-catheter induced hydrodissection (GIH) to assist radiofrequency ablation (RFA) for subcapsular hepatocellular carcinoma (HCC) with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion.METHODSThis retrospective study included 17 patients with small subcapsular HCC ineligible for ultrasonography-guided RFA who received RFA under guidance of fluoroscopy and cone-beam computed tomography immediately after iodized oil transarterial chemoembolization (TACE) between April 2011 and January 2016. In the study patients, creation of artificial ascites to protect the perihepatic structures failed due to perihepatic adhesion and GIH was attempted to separate the perihepatic structures from the ablation zone. The technical success rate of GIH, technique efficacy of RFA with GIH, local tumor progression (LTP), peritoneal seeding, and complications were evaluated.RESULTSThe technical success rate of GIH was 88.24% (15 of 17 patients). Technique efficacy was achieved in all 15 patients receiving RFA with GIH. During an average follow-up period of 48.1 months, LTP developed in three patients. Cumulative LTP rates at 1, 2, 3, and 5 years were 13.3%, 20.6%, 20.6%, and 20.6%, respectively. No patient had peritoneal seeding. Two of the 15 patients receiving RFA with GIH had a CIRSE grade 3 liver abscess, but none had complications associated with thermal injury to the diaphragm or abdominal wall near the ablation zone.CONCLUSIONGIH can be a useful method to assist RFA for subcapsular HCC with iodized oil retention in patients with failed artificial ascites due to perihepatic adhesion

Association between diet and gallstones of cholesterol and pigment among patients with cholecystectomy: a case-control study in Korea

Background: The prevalence of cholesterol gallstones is high in Western populations, while pigment gallstones are common in Asian populations. Dietary factors are suggested to be associated with gallstone risk, but their relationship with gallstone type has not been evaluated. This study investigated the association between diet and risk of cholesterol gallstone or pigment gallstone in a Korean population whose dietary pattern and type of gallstone were changed during the last 30 years. Methods: Patients with cholesterol (n = 40) and pigment (n = 59) gallstones were recruited after laparoscopic cholecystectomy and were compared with those of age- and sex-matched controls without gallstones (n = 99). Dietary intakes were assessed by trained dietitians using a semi-quantitative food frequency questionnaire. Multinomial logistic regression analysis was performed to calculate odds ratios and 95% confidence intervals to examine the associations between diet and risk for type of gallstones adjusted by potential confounders. Results: Patients with cholesterol gallstone consumed more lipid, animal lipid, beef, pork, and fried food than those with pigment gallstones and control, while patients with pigment gallstone consumed more carbohydrate and noodles than patients with cholesterol gallstone and control. In multinomial logistic regression analysis using control as reference group, dietary pattern with high consumption of beef, pork, and fried food was associated with risk of cholesterol gallstones, while there was no association between the risk of pigment gallstone and dietary pattern. In addition, control consumed more alcohol than patients with cholesterol and pigment gallstones. Conclusions: The present study suggested consumption of fat from meat and fried foods increased the risk of cholesterol gallstone, and intake of carbohydrate from noodles increased the risk of pigment gallstone