AN INNOVATIVE MEMBRANE DISTILLATION-CRYSTALLIZATION PROCESS FOR BRINE TREATMENT

Water scarcity is an issue that has emerged during recent decades and it is attributed toincreased water consumption due to rapid population growth and to climate change around the world. Desalination technologies have drawn the attention of researchers and industries as a possible solution to this problem. However, the disposal of brine byproduct to surface waters can have negative environmental impacts as brine contains chemicals from the desalination treatment and it increases the salinity of the water bodies in the disposal zone. For this purpose, a novel membrane distillation-crystallization (MDC) system with a six-tray cascading crystallizer was developed that can recover both clean water and solid salts from the desalination brines. This novel MDC system can be utilized for the treatment of reverse osmosis (RO) brine due to the advantages that it has over conventional and other alternative brine treatment technologies. These advantages are primarily related to the six-tray cascading crystallizer, which provides nucleation sites and support for crystals to grow outside the solution/air interface while having a small footprint. In addition, due to the low operating temperatures of the process (40-80 °C), the heating requirements of the system can be met with low-grade waste heat sources. The effectiveness of the current MDC system in recovering clean water and solid salts from highly concentrated solutions was tested with single-salt brines (sodium chloride (NaCl), potassium chloride (KCl), and sodium nitrate (NaNO3)). The comparison of MDC and membrane distillation (MD) under the same operating conditions showed that higher total water recovery and brine volume reductions were achieved with the MDC system. In addition, the crystallizer demonstrated the ability to recover all three solid salts outside of solution on the extended mesh in each tray of the crystallizer. The highest solid salt recovery was observed with NaNO3, which has the strongest temperature-solubility relationship. Once the MDC system was validated, the focus shifted to further exploring the crystal formation on the mesh materials of the crystallizer. The experiments evaluated the effect of material coverage, surface roughness, and the solution/air interface on amount and size of the solid salts recovered. Two common 3D-printed mesh materials, polyactic acid (PLA) and acrylonitrile butadiene styrene (ABS), were tested under stagnant and flowing conditions using a flow-through crystallizer. The experiments with the stagnant NaCl solution setup revealed that increased solid salt recoveries were achieved by combining a material coverage that provides a balance of material support and open space for crystals to form and grow outside the solution/air interface; mesh materials with a material coverage of 52.24% had the highest solid salt recoveries for both material types. Surface smoothness on the PLA meshes did not have any significant effect on solid salt recovery, whereas in the case of the ABS meshes the solid salt recovery decreased compared to the untreated mesh. Finally, the experiments with the flow-through crystallizer showed that by increasing the amount of solution/air interfacial area, the solid recovery increased. A potential mechanism that explains the crystal growth pattern on the mesh from the solution/air interface towards the non-immersed region of the mesh was also developed. In literature, continuous crystallizers and MDC systems have demonstrated the ability to recover solid salts from brines; however there have been limited studies where the focus was on the salt selectivity. Since the crystallizer consists of six trays that operate under different temperatures, its ability to perform selective salt removal was tested for two different brine mixtures. MDC setup was used with a 50% KCl and 50% NaCl mixed salt solution, while the stand-alone crystallizer was tested with a mixture of sodium carbonate (Na2CO3) and KCl with both salts at an initial concentration of 80% of their 20 °C solubility. In addition, a simple model was developed to predict the maximum amount of salts that may precipitate in each tray of the crystallizer based on their solubility at each temperature. Based on the experimental results and the modeling predictions, the crystallizer is able to selectively remove salts whose solubility increases with temperature, such as KCl

The “leopard man” sign in sarcoidosis

Images in Pneumonolog

Triiodothyronine levels in acute pulmonary embolism predict in-hospital mortality

Objective: To assess the thyroid function in patients with acute pulmonary embolism, in order to evaluate the prognostic value of thyroid hormones. Methods: We studied 31 consecutive patients with acute pulmonary embolism. Measured variables upon admission included the ratio of the partial pressure of oxygen in arterial blood to the inspired oxygen fraction (PaO2/FiO2), acute physiology and chronic health evaluation II score, risk stratification indices and plasma levels of triiodothyronine, free thyroxine, and thyroid stimulating hormone. Results: Plasma levels of triiodothyronine were below normal level in 7 patients (22.6%). Plasma triiodothyronine correlated with PaO2/FiO2 (P < 0.05) and with acute physiology and chronic health evaluation II score (P < 0.01). In four patients (12.9%) who died, triiodothyronine levels were significantly lower (P < 0.01) than that in patients who survived. In contrast both groups had similar levels of free thyroxine, and thyroid stimulating hormone. Moreover, triiodothyronine levels negatively correlated with serum markers of right ventricular dysfunction. Accordingly, in multivariate logistic regression analysis, the only factors independently associated with an increased risk of death were triiodothyronine and PaO2/FiO2. Conclusions: Our preliminary data suggest that low plasma triiodothyronine is an independent predictor of in-hospital death in patients with acute pulmonary embolism

LIVAS: A 3-D multi-wavelength aerosol/cloud database based on CALIPSO and EARLINET

We present LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies), a 3-D multi-wavelength global aerosol and cloud optical database, optimized to be used for future space-based lidar end-to-end simulations of realistic atmospheric scenarios as well as retrieval algorithm testing activities. The LIVAS database provides averaged profiles of aerosol optical properties for the potential spaceborne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm. The global database is based on CALIPSO observations at 532 and 1064 nm and on aerosol-type-dependent backscatter- and extinction-related Ångström exponents, derived from EARLINET (European Aerosol Research Lidar Network) ground-based measurements for the UV and scattering calculations for the IR wavelengths, using a combination of input data from AERONET, suitable aerosol models and recent literature. The required spectral conversions are calculated for each of the CALIPSO aerosol types and are applied to CALIPSO backscatter and extinction data corresponding to the aerosol type retrieved by the CALIPSO aerosol classification scheme. A cloud optical database based on CALIPSO measurements at 532 nm is also provided, neglecting wavelength conversion due to approximately neutral scattering behavior of clouds along the spectral range of LIVAS. Averages of particle linear depolarization ratio profiles at 532 nm are provided as well. Finally, vertical distributions for a set of selected scenes of specific atmospheric phenomena (e.g., dust outbreaks, volcanic eruptions, wild fires, polar stratospheric clouds) are analyzed and spectrally converted so as to be used as case studies for spaceborne lidar performance assessments. The final global data set includes 4-year (1 January 2008-31 December 2011) time-averaged CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) data on a uniform grid of 1° x 1° with the original high vertical resolution of CALIPSO in order to ensure realistic simulations of the atmospheric variability in lidar end-to-end simulations

Development and validation of SCOPE score: a clinical score to predict progression of COVID-19 pneumonia to severe respiratory failure

Most patients infected with SARS-CoV-2 (COVID-19) experience mild, non-specific symptoms, but many develop severe symptoms associated with an excessive inflammatory response. Elevated plasma concentrations of soluble urokinase plasminogen activator receptor (suPAR) provide early warning of progression to severe respiratory failure (SRF) or death, but access to suPAR testing may be limited. The Severe COvid Prediction Estimate (SCOPE) score, derived from circulating concentrations of C-reactive protein, D- dimers, interleukin-6, and ferritin among patients not receiving non-invasive or invasive mechanical ventilation during the SAVE-MORE study, offers predictive accuracy for progression to SRF or death within 14 days comparable to that of a suPAR concentration of ≥6 ng/mL (area under receiver operator characteristic curve 0.81 for both). The SCOPE score is validated in two similar independent cohorts. A SCOPE score of 6 or more is an alternative to suPAR for predicting progression to SRF or death within 14 days of hospital admission for pneumonia, and it can be used to guide treatment decisions