scholarly journals Continuous low-maintenance CO<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O measurements at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia

2010 ◽  
Vol 3 (2) ◽  
pp. 1399-1437 ◽  
Author(s):  
J. Winderlich ◽  
H. Chen ◽  
A. Höfer ◽  
C. Gerbig ◽  
T. Seifert ◽  
...  
Keyword(s):  
Water Vapor ◽  
Accurate Determination ◽  
Field Tests ◽  
Vegetation Period ◽  
Central Siberia ◽  
Mixing Ratios ◽  
Air Sample ◽  
The Stability ◽  
Carbon Dioxide Co2 ◽  
Tall Tower

Abstract. The Zotino Tall Tower Observatory in Central Siberia (ZOTTO, 60°48' N, 89°21' E) is an excellent location to monitor the continental carbon cycle. Since April 2009, a fully automated low maintenance measurement system based on a cavity ring-down spectroscopy (CRDS) analyzer is installed at the site to measure continuously carbon dioxide (CO2) and methane (CH4) from six heights up to 301 m a.g.l. Buffer volumes in each air line remove short term CO2 and CH4 mixing ratio fluctuations associated with turbulence, and allow continuous, near-concurrent measurements from all six tower levels. Instead of drying the air sample, the simultaneously measured water vapor is used to correct the dilution and pressure-broadening effects for the accurate determination of dry air CO2 and CH4 mixing ratios. The stability of the water vapor correction was demonstrated by repeated laboratory and field tests. The effect of molecular adsorption in the wet air lines was shown to be negligible. The low consumption of four calibration tanks that need recalibration only on decadal timescale further reduces maintenance. The measurement precision (accuracy) of 0.04 ppm (0.09 ppm) for CO2 and 0.3 ppb (1.5 ppb) for CH4 is compliant with the WMO recommendations. The data collected during the 2009 vegetation period reveals a seasonal cycle amplitude of 26.4 ppm at the 301 m level.

scholarly journals Continuous low-maintenance CO<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O measurements at the Zotino Tall Tower Observatory (ZOTTO) in Central Siberia

2010 ◽  
Vol 3 (4) ◽  
pp. 1113-1128 ◽  
Author(s):  
J. Winderlich ◽  
H. Chen ◽  
C. Gerbig ◽  
T. Seifert ◽  
O. Kolle ◽  
...  
Keyword(s):  
Water Vapor ◽  
Accurate Determination ◽  
Field Tests ◽  
Central Siberia ◽  
Mixing Ratios ◽  
Air Sample ◽  
The Stability ◽  
Carbon Dioxide Co2 ◽  
Tall Tower

Abstract. To monitor the continental carbon cycle, a fully automated low maintenance measurement system is installed at the Zotino Tall Tower Observatory in Central Siberia (ZOTTO, 60°48' N, 89°21' E) since April 2009. A cavity ring-down spectroscopy (CRDS) analyzer continuously measures carbon dioxide (CO2) and methane (CH4) from six heights up to 301 m a.g.l. Buffer volumes in each air line remove short term CO2 and CH4 mixing ratio fluctuations associated with turbulence, and allow continuous, near-concurrent measurements from all tower levels. Instead of drying the air sample, the simultaneously measured water vapor is used to correct the dilution and pressure-broadening effects for the accurate determination of dry air CO2 and CH4 mixing ratios. The stability of the water vapor correction was demonstrated by repeated laboratory and field tests. The effect of molecular adsorption in the wet air lines was shown to be negligible. The low consumption of four calibration tanks that need recalibration only on decadal timescale further reduces maintenance. The measurement precision (accuracy) of 0.04 ppm (0.09 ppm) for CO2 and 0.3 ppb (1.5 ppb) for CH4 is compliant with the WMO recommendations. The data collected so far (until April 2010) reveals a seasonal cycle amplitude for CO2 of 30.4 ppm at the 301 m level.

New Methodology for the Determination of the Vertical Center of Gravity of In-Service Semisubmersibles: Proposal and Numerical Assessment

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ivan N. Porciuncula ◽  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança
Keyword(s):  
Accurate Determination ◽  
Center Of Gravity ◽  
Practical Implementation ◽  
Numerical Assessment ◽  
Neutral Equilibrium ◽  
Inclination Angles ◽  
Numerical Tools ◽  
The Stability ◽  
Metacentric Height

Along its lifetime, an offshore unit is subjected to several equipment interventions. These modifications may include large conversions in loco that usually are not adequately documented. Hence, the accurate determination of the platform's center of gravity (KG) is not possible. For vessels with low metacentric height (GM), such as semisubmersibles, Classification Societies penalize the platform's KG, inhibiting the installation of new equipment until an accurate measurement of KG is provided, i.e., until an updated inclining test is performed. For an operating semisubmersible, the execution of this type of test is not an alternative because it implies in removing the vessel from its in-service location to sheltered waters. Relatively recently, some methods have been proposed for the estimation of KG for in-service vessels. However, as all of the methods depend on accurate measurements of inclination angles and, eventually, on numerical tools for the simulation of vessel dynamics onboard, they are not straightforward for practical implementation. The objective of the paper is to present a practical methodology for the experimental determination of KG, without the need of accurate measurements of inclinations and/or complex numerical simulations, but based on actual operations that can be performed onboard. Indeed, the proposed methodology relies on the search, identification, and execution of a neutral equilibrium condition where, for instance, KG = KM. The method is exemplified using actual data of a typical semisubmersible. The paper also numerically explores and discusses the stability of the platform under various conditions with unstable initial GM, as well as the effect of mooring and risers.

scholarly journals Influence of weather conditions during the pre-vegetation period on productivity and yield qualities of soft spring wheat seeds

2019 ◽  
Vol 20 (5) ◽  
pp. 437-446
Author(s):  
O. S. Amunova
Keyword(s):  
Seed Germination ◽  
Spring Wheat ◽  
Field Tests ◽  
Weather Conditions ◽  
Vegetation Period ◽  
Reproductive Period ◽  
Average Yield ◽  
Seed Formation ◽  
Yield Structure ◽  
Seminal Roots

Eleven genotypes of soft spring wheat were studied in a series of field and laboratory experiments in 2014 - 2018. The laboratory test included accounting for seed germination and assessing the physiological parameters of seedlings (number of seminal roots, dry matter mass of roots and shoots and their ratio (RSR index)). The field tests included phenological observa-tions, assessment of genotypes by productivity and average yield. The average yield of wheat during the years of study was 1.93-4.92 t/ha and depended on weather conditions during the period of grain formation. The trait “1000-grain mass” was formed under the influence of the genotype (68.1%), the portion of influence of weather conditions was 11.8%. It has been established that the duration of the reproductive period of soft spring wheat in the Kirov region should be at least 40 days. Reducing the duration of the reproductive period leads to a decrease in seed germination capacity. Seeds the formation and development of which took place at the optimum temperature of 16 ºС, by germination spent the most part of seed reserve substances for the development of the aboveground part of the plant (RSR index = 0.70). Under these conditions, the varieties with a lower root index were characterized by high values of the elements of yield structure. At the increased average daily air temperature (by 2-4 oC), seeds that could germinate with a significantly higher number of seminal roots (6.6-9.0%) developed on the maternal plants. During the germination of such seeds, the plastic substances distributed evenly between the shoots and seminal roots (RSR index = 0.94-0.98). The increased influx of assimilates to root system of seedlings could be explained by the fact that the process of seed formation on the maternal plants took place under conditions close to stressful and the adapted seeds spent more reserve substances for root development.

Preparation of Cross-Linked Cellulase Aggregate and Application to Cool Finishing of Cotton Fabric

2021 ◽  
Vol 8 (3) ◽  
pp. 1-7
Author(s):  
Gang Bai ◽  
Bingbing Feng ◽  
Yanchun Liu ◽  
Shujiao Dai
Keyword(s):  
Water Vapor ◽  
Cotton Fabric ◽  
Silicone Oil ◽  
Air Permeability ◽  
Kinetic Friction ◽  
Capillary Effect ◽  
Bending Rigidity ◽  
Moisture Permeability ◽  
Treated Sample ◽  
The Stability

Cellulase was immobilized by cross-linked enzyme aggregation to improve the stability of cellulase. The prepared cross-linked cellulase aggregates (CLCAs) and ice silicone oil were used for the cool finishing of cotton fabric. The results showed that the CLCAs extended the cellulase stability compared to free cellulase. The surface softness, smoothness, moisture permeability, and air permeability of the cotton fabric increased after CLCAs and ice silicone oil treatment. Shearing rigidity of the treated sample was 0.44 cN/(cm·deg), bending rigidity was 0.0069 cN cm, and the drape coefficient was 29.3%. Coefficient of kinetic friction of the treated sample was 0.186. The capillary effect of the treated fabric was 12.1 cm/(30 min). Air permeability was 354.3 L/(m2·s). Moisture penetrability was 3.912 g/(m2·d). The thermal and water-vapor resistance were 0.0194 m2·°C/W and 4.691 Pa·m2/W, respectively.

Cardiac Troponin I Microfluidic Chip Driven by Adaptive Pressure

2020 ◽  
Vol 12 (10) ◽  
pp. 1239-1247
Author(s):  
Xingshang Xu ◽  
Yuan Liu ◽  
Zhu Chen ◽  
Hui Chen ◽  
Yan Deng ◽  
...  
Keyword(s):  
Microfluidic Chip ◽  
Whole Blood ◽  
Cardiac Troponin ◽  
Troponin I ◽  
Accurate Determination ◽  
Cardiac Troponin I ◽  
Chip Surface ◽  
Layer Composite ◽  
Novel Strategy ◽  
The Stability

To develop and design an adaptive microfluidic chip for accurate determination of cardiac troponin I (cTnI) in whole blood sample and explore the operating parameters of the chip in detecting cTnI, in order to provide a novel strategy for the detection of cTnI, cTnI microfluidic chip was prepared by injection moulding, and the improved polystyrene polymer was used as the chip substrate to construct a three-layer composite structure, namely the upper, middle, and lower layers. The antihuman troponin I antibody I/II was grafted onto the chip surface to construct the detection reaction zone using UV-induced production of surface-active free radicals. The stability of the chip preparation process, the running performance of the chip, and the analytical performance of the whole blood samples were investigated. It was shown that I adaptive pressure-driven microfluidic chip has the advantages of easy bonding, integration, and a simple and stable production process. In the actual detection and analysis, the chip has high selectivity for cTnI in whole blood, lower detection limit (0.054 ng/mL), and small difference between batches (RSD% 2.50%). Therefore, the chip is assumed to provide novel strategy for the assessment of myocardial infarction by detecting cTnI.

Past Changes in Ocean Carbonate Chemistry

2011 ◽  
Author(s):  
Richard E. Zeebe ◽  
Andy Ridgwell
Keyword(s):  
Co2 Emissions ◽  
Metal Speciation ◽  
Marine Organisms ◽  
Geochemical Environment ◽  
Surface Ocean ◽  
Carbonate Ion ◽  
Mesocosm Experiments ◽  
Decreasing Ph ◽  
The Stability ◽  
Carbon Dioxide Co2

Over the period from 1750 to 2000, the oceans have absorbed about one-third of the carbon dioxide (CO2) emitted by humans. As the CO2 dissolves in seawater, the oceans become more acidic and between 1750 and 2000, anthropogenic CO2 emissions have led to a decrease of surface-ocean total pH (pH T) by ~0.1 units from ~8.2 to ~8.1 (see Chapters 1 and 3). Surface-ocean pHT has probably not been below ~8.1 during the past 2 million years (Hönisch et al. 2009). If CO2 emissions continue unabated, surface-ocean pH T could decline by about 0.7 units by 2300 (Zeebe et al. 2008). With increasing CO2 and decreasing pH, carbonate ion (CO32–) concentrations decrease and those of bicarbonate (HCO-3) rise. With declining CO32– concentration ([CO32–]), the stability of the calcium carbonate (CaCO3) mineral structure, used extensively by marine organisms to build shells and skeletons, is reduced. Other geochemical consequences include changes in trace metal speciation (Millero et al. 2009 ) and even sound absorption ( Hester et al. 2008 ; Ilyina et al. 2010 ). Do marine organisms and ecosystems really ‘care’ about these chemical changes? We know from a large number of laboratory, shipboard, and mesocosm experiments, that many marine organisms react in some way to changes in their geochemical environment like those that might occur by the end of this century (see Chapters 6 and 7). Generally (but not always), calcifying organisms produce less CaCO3, while some may put on more biomass. Extrapolating such experiments would lead us to expect potentially significant changes in ecosystem structure and nutrient cycling. But can one really extrapolate an instantaneous environmental change to one occurring on a timescale of a century? What capability, if any, do organisms have to adapt to future ocean acidification which is occurring on a slower timescale than can be replicated in the laboratory? Simultaneous changes in ocean temperature and nutrient supply as well as in organisms’ predation environment may create further stresses or work to ameliorate the effect of changes in ocean chemistry.

Factors affecting constancy of acetate concentration and correct determination of methanogenic activity in pH-stat experiments

2003 ◽  
Vol 48 (6) ◽  
pp. 111-118
Author(s):  
M. Mösche ◽  
U. Meyer
Keyword(s):  
Accurate Determination ◽  
Original Method ◽  
Experimental Conditions ◽  
Methanogenic Activity ◽  
Factors Affecting ◽  
Acetate Concentration ◽  
Correct Determination ◽  
Ph Stat ◽  
The Stability

The determination of methanogenic activity with a pH-stat titration bioassay is evaluated utilising a mathematical model of this system. For given kinetic parameters and experimental conditions the model calculates the development of titrant flow and acetate concentration during experiments. Simulations of experiments under various conditions are compared. They show that the original method inherently causes a strong drift of acetate concentration during the experiments and a misestimation of methanogenic activity. As a solution to these disadvantages the addition of sodium hydroxide to the titrant and a careful control of pH during flushing the reactor with gas prior to the experiment are recommended. In this way a better constancy of acetate concentration and a more accurate determination of methanogenic activity should be achievable. The accuracy of this method is limited by the stability of pH-electrode calibration parameters.

scholarly journals Intercomparison of midlatitude tropospheric and lower-stratospheric water vapor measurements and comparison to ECMWF humidity data

2018 ◽  
Vol 18 (22) ◽  
pp. 16729-16745 ◽  
Author(s):  
Stefan Kaufmann ◽  
Christiane Voigt ◽  
Romy Heller ◽  
Tina Jurkat-Witschas ◽  
Martina Krämer ◽  
...  
Keyword(s):  
Water Vapor ◽  
Climate Impact ◽  
Cloud Formation ◽  
Mean Values ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
Quality Of Water ◽  
Research Aircraft ◽  
German Aerospace

Abstract. Accurate measurement of water vapor in the climate-sensitive region near the tropopause is very challenging. Unexplained systematic discrepancies between measurements at low water vapor mixing ratios made by different instruments on airborne platforms have limited our ability to adequately address a number of relevant scientific questions on the humidity distribution, cloud formation and climate impact in that region. Therefore, during the past decade, the scientific community has undertaken substantial efforts to understand these discrepancies and improve the quality of water vapor measurements. This study presents a comprehensive intercomparison of airborne state-of-the-art in situ hygrometers deployed on board the DLR (German Aerospace Center) research aircraft HALO (High Altitude and LOng Range Research Aircraft) during the Midlatitude CIRRUS (ML-CIRRUS) campaign conducted in 2014 over central Europe. The instrument intercomparison shows that the hygrometer measurements agree within their combined accuracy (±10 % to 15 %, depending on the humidity regime); total mean values agree within 2.5 %. However, systematic differences on the order of 10 % and up to a maximum of 15 % are found for mixing ratios below 10 parts per million (ppm) H2O. A comparison of relative humidity within cirrus clouds does not indicate a systematic instrument bias in either water vapor or temperature measurements in the upper troposphere. Furthermore, in situ measurements are compared to model data from the European Centre for Medium-Range Weather Forecasts (ECMWF) which are interpolated along the ML-CIRRUS flight tracks. We find a mean agreement within ±10 % throughout the troposphere and a significant wet bias in the model on the order of 100 % to 150 % in the stratosphere close to the tropopause. Consistent with previous studies, this analysis indicates that the model deficit is mainly caused by too weak of a humidity gradient at the tropopause.

Water-vapor Measurements in the Lower Stratosphere

1974 ◽  
Vol 52 (8) ◽  
pp. 1527-1531 ◽  
Author(s):  
H. J. Mastenbrook
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Marked Decrease ◽  
Vapor Concentration ◽  
Water Vapor Concentration ◽  
Mixing Ratio ◽  
Stratospheric Water Vapor ◽  
Mixing Ratios ◽  
Natural Concentration ◽  
General Range

Nearly 10 years of water-vapor measurements to heights of 30 km provide a basis for assessing the natural concentration of stratospheric water vapor and its variability. The measurements which began in 1964 have been made at monthly intervals from the mid-latitude location of Washington, D.C, using a balloon-borne frost-point hygrometer. The observations show the mixing ratio of water-vapor mass to air mass in the stratosphere to be in the general range of 1 to 4 p.p.m. with a modal concentration between 2 and 3 p.p.m. An annual cycle of mixing ratio is evident for the low stratosphere. A trend of water-vapor increase observed during the first 6 years does not persist beyond 1969 or 1970. The 6 year increase was followed by a marked decrease in 1971, with mixing ratios remaining generally below 3 p.p.m. thereafter. The measurements of recent years suggest that the series of observations may have begun during a period of low water-vapor concentration in the stratosphere.

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