EVLW and its Importance in Fluid Management

Fluid management and optimization is one of the most frequently observed problems in anesthesiology and critical care. An ideal hemodynamic management increases oxygen supply to tissues, improves postoperative outcomes and decreases surgical costs. Extravascular lung water (EVLW) measurement has gained widespread acceptance in the early prediction and management of adverse effects caused by fluid treatment. The fundamental aim of acute circulatory failure treatment is to improve tissue perfusion and oxygenation while avoiding fluid overload. EVLW consists of extravascular interstitial, intracellular, alveolar and lymphatic fluid in the lungs and its normal values are 3-7 ml kg-1. Studies have reported that values above 10 ml kg-1 as a cut-off value points to pulmonary edema. Although the gold standard in EVLW measurement is the gravimetric method, lung ultrasound and transpulmonary thermodilution is more widely utilized since gravimetric measurement can only be performed post-mortem. EVLW measurement is expected to gain importance in the hemodynamic measurement of ALI/ARDS patients and future studies will benefit from focusing on EVLW based fluid therapy.

Performance of snow density measurement systems in snow stratigraphies

Gravimetric and dielectric permittivity measuring systems are applied to measure snow density, but few studies have addressed differences between the two measurement systems under complex snowpack conditions. A field experiment was conducted to measure snow density using the two measurement systems in different stratigraphical layers consisting of fragmented precipitation particles (DF), faceted crystals particles (FC), depth hoar (DH) and melt forms (MF), and the performance of measurement systems were analyzed and compared. The results showed that the measured density from the gravimetric measurement system was significantly higher than from the dielectric permittivity measurement system. The precision and accuracy of the gravimetric measurement system was higher than that of the dielectric permittivity measurement system in the DF, FC and DH layers, but the precision and accuracy of two measurement systems were similar in the MF layers. By comparing the precision and accuracy as well as merits and drawbacks of the two measurement systems, it was concluded that using gravimetric measurement system during dry snow and dielectric permittivity measurement system during wet snow will help surveyors obtain more reliable data. Furthermore, the study provided an approach which will facilitate the integration of the data obtained from different studies with different measurement systems into global databases.

Possible albedo reduction due to light absorbing impurities in snowpack observed at various sites

<p>Possible albedo reduction due to light absorbing impurities (LAI) in snowpack observed at various sites in the world are investigated. Reviewing previously measured black carbon (BC) concentrations, their values distribute in a range of 0.07-0.25 ppbw (ng of BC in g of snow) in Antarctica, 0.55-20 ppbw in Greenland Ice Sheet (GrIS), 4.4-87.6 ppbw for the other Arctic except GrIS, and 4-1221 ppbw for mid-latitudes. As albedo reduction rate by LAI depends on snow grain size, it is more enhanced by larger grain snow such as melt form (melting snow) than smaller grain snow such as precipitation particles (new snow). By assuming two typical snow grain radii r<sub>s</sub> = 1000 and 50 µm, respectively for those snow grain shapes, the albedo reduction as a function of BC concentration can be calculated with physically based snow albedo model. The result indicates that albedo in Antarctic snow is not affected by BC in any case of snow grain radius. In GrIS albedo reduction due to BC is small around 0.006 for r<sub>s</sub> = 50 µm (new snow) but it rises to 0.026 for r<sub>s</sub> = 1000 µm (melting snow), suggesting a few percent of albedo reduction could occur under warmer climate condition due to enhanced snow metamorphism. In the other Arctic except GrIS, the maximum albedo reductions for r<sub>s</sub> = 50 µm (1000 µm) are 0.015 (0.064) at the maximum BC concentration (87.6 ppbw). For. mid-latitudes, it is 0.070 (0.24) for r<sub>s</sub> = 50 µm (1000 µm) at the maximum BC concentration (1221 ppbw). These results mean albedo reduction in highly polluted area of mid-latitudes cannot be ignored even in case of new snow and is more serious for melting snow.</p><p>We have conducted energy budget and snow pit observations at Sapporo (43°N, 141°E, 15 m a.s.l), Japan since 2005. In addition, elemental carbon (EC~BC) and mineral dust concentrations in snowpack were also monitored for snow samples collected twice a week from 2007 by the thermal optical reflectance (TOT) method and gravimetric measurement of a filter. During 10 years from 2007 to 2017, the medians of EC and dust concentrations are 196 ppbw and 2700 ppbw, respectively. Using those data, contribution of LAI to albedo reduction and the radiative forcing (RF) were estimated. The 10-year-mean albedo reduction and RF due to BC+dust are 0.053 and +6.7 Wm<sup>-2</sup>, respectively, in which BC effect on albedo reduction is 5.6 times larger than dust. The albedo reduction by BC+dust for only melting period is 0.151, that is 4.8 times larger than that for accumulation period. The effect of LAI on albedo reduction is enhanced by snow grain growth as well as an increase of LAI in melting period compared to that for accumulation season.</p>

COMPARATIVE ANALYSIS OF FOREST PLANTATIONS CUTTING AGE BASED ON VOLUMETRIC AND GRAVIMETRIC UNITS

The objective of this work was to evaluate the technical and economic cutting age of forest plantations considering the wood market under volumetric and gravimetric measurement units. Volumetric production and wood basic density for Eucalyptus urophylla clones stands were obtained from a forest company in the Jequitinhonha’s region, Minas Gerais State, for ages of 3 to 9 years. It was estimated: mass per hectare; technical cutting age (TCA) for volume and mass; and economic viability at different interest rates. Data was divided by three clones, being the denser (C), passing through (B) median density, and less denser (A). The results showed that in alternating volumetric for gravimetric unit, the TCA occurs at least one year later. For the economic analysis, the results demonstrated that projects for wood commercialization by gravimetric measurement are economically viable when using high-density clones, due to the higher amount of mass per volume. For clones with low density and high volumetric productivity, the analysis must be done from a volumetric point of view, as the economic results were 23% higher than in the mass analysis. It was concluded that the adoption of the gravimetric unit of measure in the forest sector tends to cause significant changes in project management, improving wood characteristics for energy by postponing the cutting age and making more sensible the genetic material selection.

Feasibility of Using an Electrolysis Cell for Quantification of the Electrolytic Products of Water from Gravimetric Measurement

A gravimetric method for the quantitative assessment of the products of electrolysis of water is presented. In this approach, the electrolysis cell was directly powered by 9 V batteries. Prior to electrolysis, a known amount of potassium hydrogen phthalate (KHP) was added to the cathode compartment, and an excess amount of KHCO3 was added to the anode compartment electrolyte. During electrolysis, cathode and anode compartments produced OH−(aq) and H+(aq) ions, respectively. Electrolytically produced OH−(aq) neutralized the KHP, and the completion of this neutralization was detected by a visual indicator color change. Electrolytically produced H+(aq) reacted with HCO3−(aq) liberating CO2(g) from the anode compartment. Concurrent liberation of H2(g) and O2(g) at the cathode and anode, respectively, resulted in a decrease in the mass of the cell. Mass of the electrolysis cell was monitored. Liberation of CO2(g) resulted in a pronounced effect of a decrease in mass. Experimentally determined decrease in mass (53.7 g/Faraday) agreed with that predicted from Faraday’s laws of electrolysis (53.0 g/Faraday). The efficacy of the cell was tested to quantify the acid content in household vinegar samples. Accurate results were obtained for vinegar analysis with a precision better than 5% in most cases. The cell offers the advantages of coulometric method and additionally simplifies the circuitry by eliminating the use of a constant current power source or a coulometer.