column liquid water content

Top PDF column liquid water content:

Simulation of the microwave emission of multi-layered snowpacks using the Dense Media Radiative transfer theory: the DMRT-ML model

Simulation of the microwave emission of multi-layered snowpacks using the Dense Media Radiative transfer theory: the DMRT-ML model

Figure 9 shows the relationship between the brightness tem- perature at 19 GHz and horizontal polarization as a func- tion of the total column liquid water content. The snowpack is considered homogeneous, except that the liquid water is concentrated in the top 10 cm. This calculation confirms the strong influence of the liquid water on brightness tempera- ture, which is exploited to detect snowmelt events from pas- sive microwave observations (e.g. Picard and Fily, 2006). It also shows that brightness temperature reaches a nearly con- stant value from about 0.5 kg m −2 of liquid water. This fea- ture explains why the retrieval of the amount of liquid wa- ter from passive microwave observation is probably impos- sible. The threshold value, 0.5 kg m −2 , is close to value ob- tained with the MEMLS model (Tedesco et al., 2007) and that obtained indirectly by comparing observations and out- puts of the RACMO regional snow and atmosphere model (Kuipers Munneke et al., 2012).
Show more

18 Read more

Study of the Performance of a New Kind of Downhole Gas-Liquid Separation with High Gas Content

Study of the Performance of a New Kind of Downhole Gas-Liquid Separation with High Gas Content

During gas extraction, as the gas pressure and gas flow rate gradually decrease, the output of gas reservoir water or liquids cannot be carried out of the wellbore by the natural air flow and is thus stranded in the wellbore [1-5]. These liquids accumulate over a period of time in the bottom hole to form a fluid column, which causes additional hydrostatic pressure in the reservoir. Under this condition, the gas well energy flow declines [6-9]. Eventually, the accumulated fluid column in the wellbore will cause the gas well to stop production [10-13].
Show more

5 Read more

Validated stability indicating liquid chromatographic determination of ebastine in pharmaceuticals after pre column derivatization: Application to tablets and content uniformity testing

Validated stability indicating liquid chromatographic determination of ebastine in pharmaceuticals after pre column derivatization: Application to tablets and content uniformity testing

Separation was achieved on an EC nucleosil C18-SN: 4115568 column (150 mm × 4.6 mm id (5 mm) com- bined with a guard column (Merck, Darmstadt, Ger- many). The columns were operated at ambient temperature. The analytical system was washed daily with 60 ml of 1:1 mixtures of water and methanol to eliminate the mobile phase; this did not cause any change in the column performance. The mobile phase was prepared by mixing (acetonitrile/methanol; 1/4) with 0.03 M Britton Robinson buffer in a ratio of 65:35 v/v at pH of 4.2. The mixture was then sonicated for 30 minutes. The resulting mobile phase was filtered through a 0.45 μ m membrane filter (Millipore, Ireland).
Show more

15 Read more

A 20-year record (1998–2017) of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen)

A 20-year record (1998–2017) of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen)

Permafrost, which is defined as ground that has remained frozen continuously for 2 years or more, covers large parts of the land surface in the Northern Hemisphere, amounting to about 15 million km 2 (Brown et al., 1998). The range in tem- peratures and water and ice content of the upper surface layer of seasonally freezing and thawing ground (the active layer) determines the biological and hydrological processes that op- erate in these areas. Thermal degradation of permafrost over the last few decades has been reported from 10 available circum-Arctic boreholes (Romanovsky et al., 2010) with a recent update by Romanovsky et al. (2017). Warming and thawing of permafrost and an overall reduction in the area that it covers under future climate change scenarios have been predicted in all recent climate models, but at widely varying rates (Koven et al., 2012). Continued observations, not only of permafrost thermal data but also of the multiple other types of data required to understand the changes to per- mafrost, are therefore of great importance. The data required include information on the upper boundary condition of the soil (specifically on snow cover), on atmospheric conditions and on various subsurface state variables (e.g., volumetric liquid water content). The seasonal snow cover in Arctic per- mafrost regions insulates the permafrost surface for many months of the year and has an important effect on the thermal regime of permafrost (Langer et al., 2013; López-Moreno et al., 2016). The soil’s water content determines not only its hydrologic and thermal properties, but also the amount of la- tent heat that is either required for the seasonal thaw in spring or produced during fall. In view of these dependencies, the data sets (including snow cover and the thermal state of the soil and permafrost), ideally at the same resolution as any meteorological input data, will be of great value for evaluat- ing permafrost models (or land surface models intended for permafrost regions). In this paper we present data that incor- porate subsurface components of heat and mass flux, prop- erties of the snow cover and weather data from the Bayelva high Arctic permafrost site.
Show more

36 Read more

Geotechnical aspects of sewage sludge monofills

Geotechnical aspects of sewage sludge monofills

example new licences granted in Ireland under the Waste Management Act 2 by the Environmental Protection Agency. Operators of existing landfills are also increasingly reluctant to accept dewatered sewage sludge due to concerns about sludge handling, trafficability and instability of the landfill slopes. Increasingly strict legislation, higher landfill taxes and increased competition for landfill space are causing the water industry to look for more effective strategies for sludge disposal. The paper considers dedicated sludge-to-landfill operations which involve placement of the sludge material in layers and compaction to the maximum dry density, thereby maximising the operational life for the landfill site. The liquid sludge is dewatered and dried at the wastewater treatment plant to the optimum water content for compaction in the landfill. Substantial reductions in the cost of trucking the sludge to the landfill are achieved by the drying process. Leachate production at the landfill also decreases significantly. However, biologically stabilised sludge, generally achieved by sludge thickening and digestion processes, 3 is required. O’Kelly 4 reported some engineering properties of anaerobically digested sewage sludge from the Tullamore municipal wastewater treatment plant (Tullamore, Ireland). The treatment plant serves an urban population of approximately 12 000. The results of additional index, compaction, shear strength and compressibility tests are presented and the database of engineering properties applied, in particular to aspects of the design, construction and management of sewage sludge monofills. Since sewage sludge is largely an organic material, consideration is also given to the effects of further microbial decomposition on landfill performance, in particular the reduction in shear strength due to a build-up of pore water and pore gas pressures.
Show more

5 Read more

Hydraulic and transport parameter assessment using column infiltration experiments

Hydraulic and transport parameter assessment using column infiltration experiments

In this section, the identifiability of the parameters is investi- gated for seven different scenarios of measurement sets (Ta- ble 1). In the first scenario, only measured pressure heads and cumulative outflow are used for the calibration. Scenarios 2 to 5 investigate the benefit of adding measured water contents and/or solute outlet concentrations to pressure heads and out- flow. The last scenarios (6, 7) investigate the use of mea- sured cumulative outflow and concentration breakthrough at the column outflow because these measurements do not re- quire intrusive techniques. Scenarios 5 to 7 investigate the effects of solute injection duration on the identifiability of the parameters as well.
Show more

13 Read more

Thermodynamic phase retrieval of convective clouds: impact of sensor viewing geometry and vertical distribution of cloud properties

Thermodynamic phase retrieval of convective clouds: impact of sensor viewing geometry and vertical distribution of cloud properties

Spaceborne and airborne passive remote sensing meth- ods are based on measuring the reflected solar and emit- ted terrestrial radiances. Such observations have successfully been applied to retrieve the cloud macro- and microphysical- structure. The retrieval of vertical profiles from nadir or zenith radiance observations is inherently limited to deter- mine either bulk properties integrated over the entire column (like the optical thickness) or to quantities representative of limited cloud portions depending on cloud thickness (like the thermodynamic phase or droplet size). Several publica- tions have shown studies concerning the derivation of verti- cal properties of cloud layers from satellite observation. They are based on spectral differences in penetration depths of NIR radiation using the concept of weighting functions (Plat- nick, 2000; Wang et al., 2009; Zhang et al., 2010). Chang and Li (2002) and Chang and Li (2003) proposed a method for retrieving the vertical profile of effective radius for strati- form clouds by combining the reflectances at three absorbing near-infrared wavelength bands (1.6, 2.1, 3.7 µm). Recently, Kokhanovsky and Rozanov (2012) presented an approach for shallow warm clouds which uses the optimal estimation method and direct radiative transfer simulations of respec- tive weighting functions. However, vertical information of deep convective clouds cannot be derived from nadir obser- vations applying these methods. Current satellite and aircraft retrieval methods are based mostly on one-dimensional (1-D) radiative transfer simulations which assume that clouds are horizontally homogeneous. While such an approach might be feasible for a cloud-top-viewing instrument, for the pro- posed cloud-side-scanning geometry the consideration of 3- D effects is mandatory. Zinner et al. (2008) and Martins et al. (2011) presented an airborne cloud scanner that measures spectral radiances reflected from cloud sides which poten- tially allows for the retrieval of the vertical profile of cloud droplet sizes near cloud edges. Assuming non-precipitating clouds this vertical distribution corresponds to the vertical profile of the whole cloud (Rosenfeld and Lensky, 1998; Freud et al., 2008).
Show more

9 Read more

Protocol: An updated integrated methodology for analysis of metabolites and enzyme activities of ethylene biosynthesis

Protocol: An updated integrated methodology for analysis of metabolites and enzyme activities of ethylene biosynthesis

then, several methods have been published that allow the direct quantification of ACC by gas chromatogra- phy-mass spectrometry (GC-MS) [6], liquid chromato- graphy-mass spectrometry (LC-MS) [7] or capillary electrophoresis with laser-induced fluorescence detec- tion (CE-LIF) [8]. Each technique has its own advan- tages and disadvantages. For GC-MS and CE-LIF analysis samples need to be derivatised before measure- ment, which makes the procedure quite complex and time-consuming. The main disadvantage however is the poor reproducibility of the derivatisation procedure when dealing with low ACC concentrations. ACC con- tents can be directly measured using LC-MS, but the technique is very expensive, both in terms of the equip- ment required as well as the consumables. This makes LC-MS unfavourable when large amounts of samples are involved. Even though the procedure of Lizada and Yang measures ACC indirectly, it allows for relatively fast mea- surements with little sample preparation and using low cost equipment. If the fluctuating efficiency of the turn- over reaction is taken into account in a proper way, fol- lowing the protocol outlined in the present manuscript, the technique provides a convenient and accurate way to quantify ACC in, for example, fruit samples.
Show more

10 Read more

A Comparative Study of Cloud Liquid Water Content from Radiosonde Data at a Tropical Location

A Comparative Study of Cloud Liquid Water Content from Radiosonde Data at a Tropical Location

The study of cloud properties is increasingly important in the context of climate research of troposphere. One of the sources of global warming is the cloud feedback and wa- ter vapour feedback. Again as relative humidity has a greater impact on cloud formation, knowledge of mois- ture distribution of troposphere is necessary to know the cloud process [1]. Parameterization of cloud component is very much necessary as cloud plays a dual role in af- fecting outgoing long wave radiation (OLR) as well as reflecting incoming solar radiation [2]. Cloud Liquid water content (LWC) plays also a dominant role in att- enuating electromagnetic signal [3]. Stability of air is another important matter of concern as cloud develop- ment is associated with it. As air parcel is very large, it is realistically considered that it does not exchange any heat with surrounding as it rises and due to the expansion in volume it cools at a relatively constant rate. Depending on whether the air is saturated or unsaturated, the impor- tant parameter of cloud formation i.e. moist adiabatic lapse rate (MALR) or dry adiabatic lapse rate (DALR) comes into the picture. To know the profile of liquid wa- ter content and thereby total liquid water content for a particular day and also the amount of water vapour in the atmosphere the knowledge of humidity profile is also important. Water vapour can be related to low level hu- midity and low atmospheric humidity can be obtained as
Show more

6 Read more

USE OF DIFFERENT NON – TRADITIONAL ADDITIVES FOR SOIL STABILIZATION

USE OF DIFFERENT NON – TRADITIONAL ADDITIVES FOR SOIL STABILIZATION

Liquid stabilizer like XRF reduces plasticity and shrinkage by elimination of reabsorption of water molecules. They reduce the moisture content by ionizing and exchanging the water molecule on the surface of clay platelets. Maximum dry density is increased by nutralizing and orderly rearranging the clay platelets.The compressive strength is increased by inter particles bonding.

6 Read more

Use of neural network for modeling of liquid-liquid extraction process in the RDC column

Use of neural network for modeling of liquid-liquid extraction process in the RDC column

Abstract Several Mathematical Models have been developed for processes in- volving Rotating Disc Contactor (RDC) Column. These models indicated that the hydrodynamic and the mass transfer processes are important factors for the column performances. Usually, the mathematical simulation models describing the processes in the column are very complex. It also needs excessive computer time to produce simulation data for further analysis. Therefore, an alternative approach based on Artificial Neural Network is considered to assist in speeding up the simulation process. This paper presents a new application of Artificial Neural Network (ANN) techniques to the modeling of the liquid-liquid extrac- tion process in the RDC Column. In this work, the ANN was trained with the simulated data obtained from Arshad (2000). The Neural Network models are able to generate 128 simulated data for RDC column with RMS error value of 1.0E-07. The comparison between Neural Network output and Mathematical Model(2000) output is also presented.
Show more

13 Read more

An infiltration column to investigate experimentally the response of the soil-plant-atmosphere continuum

An infiltration column to investigate experimentally the response of the soil-plant-atmosphere continuum

High-Capacity Tensiometers were pre-pressurised at 4MPa before use and cycles of cavitation and pre- pressurisation were applied to improve the perfor- mance of the tensiometer in terms of maximum sus- tainable suction and measurement duration (Taranti- no (2004)). After removal from the saturation chamber, the tensiometers were placed in free water for zeroing. A kaolin paste –approximately at the plastic limit –was applied on the tensiometer porous filter to ensure proper hydraulic continuity with the soil. The loss of water from the soil is a slow pro- cess, the thin layer (few millimetres) of kaolin paste is then capable of transferring the water tension to the HCT with no appreciable delay—after the time interval necessary to reach a hydraulic equilibrium with the specimen (in the range of few hours).
Show more

6 Read more

Gas liquid simulation of an airlift bubble column reactor

Gas liquid simulation of an airlift bubble column reactor

The principle function of airlift reactor while the gas is injected into the riser and the resulting difference between average densities in the riser and in the downcomer provides a driving force for liquid circulation. Also solid particles can be present, for example catalyst and biomass (Simcik et al., 2011). In other words, airlift reactors are distinguished by fluid circulation in a well-defined and clear cyclic pattern through channels providing a loop for recycling the liquid. The gas is injected at the bottom of the reactor then both of the gas and liquid flow upwards in the riser. The gas disengages totally or partially from the liquid. The liquid flows down from the top to the bottom of the reactor in the downcomer. The different volumes of gas retained in the riser and the downcomer create a pressure difference that forces the fluid from the bottom of the downcomer towards the riser of the liquid circulating (Veno et al., 2007). This model can be applied for a two or three-phase flow with low viscosity in a Newtonian liquid
Show more

40 Read more

Simulation of the Wet Phosphoric Acid						Extraction along a Continuous Column - Volume 1 Number 4 (Dec. 2010) - IJCEA

Simulation of the Wet Phosphoric Acid Extraction along a Continuous Column - Volume 1 Number 4 (Dec. 2010) - IJCEA

In the present work, the simulation of WPA extraction along a continuous column has been conducted. The driving forces for mass transfer were based on the partition ratios found in laboratory experimental investigations. The adopted mass transfer coefficients were obtained from pilot scale extraction experiments. The performed simulations led to assess the effect of operating conditions on the extraction performance.

6 Read more

Prediction of In-Cloud Icing Conditions at Ground Level Using the WRF Model

Prediction of In-Cloud Icing Conditions at Ground Level Using the WRF Model

Unfortunately there are not many data available from the actual site on Ylla¨s to reveal potential model errors, except instantaneous values of temperature, wind speed, SLWC, and MVD at ground level. However, there is a meteorological observatory at Sodankyla¨ (World Mete- orological Organization station code EFSO 02836) ap- proximately 100 km to the east of Ylla¨s. From this station radiosoundings are available 2 times per day at 0000 and 1200 UTC. A comparison between predicted and mea- sured profiles at Sodankyla¨ shows that the model in gen- eral has a good representation of the weather situation in the cases simulated. Both measured and simulated profiles show the air reaching saturation with respect to water at ground level or close to ground level with the moist air masses often trapped inside or below an inversion layer. Some minor discrepancies are found, and the case with largest deviation is shown in Fig. 3. In this case there is a shallow but strong temperature inversion close to the ground that is not captured by the WRF model, causing the modeled temperature at Sodankyla¨ to be approxi- mately 58C too high at ground level. However, since the entire inversion layer is below the height of Ylla¨s this error does not affect the predictions on the hilltop where the predicted temperature matches the measurement very well. The overall mean absolute error (MAE) of the tem- perature predictions for Sodankyla¨ is 1.68C including the case shown in Fig. 3.
Show more

15 Read more

Simultaneous and synergistic profiling of cloud and drizzle properties using ground-based observations

Simultaneous and synergistic profiling of cloud and drizzle properties using ground-based observations

The true shape parameter is not strictly constant along the vertical direction; it is mostly close to 6 and decreasing to around 2 at the cloud base or cloud top. The retrieval is per- formed with ν = 5.5 and with the radar calibration factor fixed to 1 to match the true values. The lidar calibration fac- tor is retrieved on average with a 5 % accuracy. For compar- ison purposes, we also include in the last column of Table 2 the run where the shape parameter ν is free within a fixed range, i.e., between 2 and 10. The result is that the noise of the retrieved products increases but there is very little sys- tematic offset. The optimized ν is found to have a mean of 5.98 (RMSD = 2.01), which is very close to the true ν. By comparing the last two columns in Table 2, it is apparent that when ν is not fixed the RMSD increases significantly due to the large column-to-column fluctuation but the mean values are hardly affected. The extinction coefficient is found to be relatively stable against the variation in ν, possibly because its retrieval is largely dependent on the β profile.
Show more

27 Read more

Liquid Column Deformation and Particle Size Distribution in Gas Atomization

Liquid Column Deformation and Particle Size Distribution in Gas Atomization

During close coupled atomization, a liquid column or sheet is perturbed by a high velocity gas flow and is bro- ken up into droplets, in a two stage process. In the first stage, that of primary atomization [1], the surface of the melt is disturbed by a sinusoidal oscillation [2] and is subsequently broken up into large drops or unstable bod- ies, the ligaments [3]. During the subsequent stage of secondary atomization, the drops/ligaments may further disintegrate in flight, either via a low-turbulence mecha- nism [4] or in a more chaotic high-turbulence stripping fashion [5]. The principle of gas atomization is shown in Figure 1. In spray forming, atomization of a molten metal or alloy causes rapid solidification of the drops in flight. The spray’s subsequent impingement on a sub- strate produces a spray cast of varying microstructure. It is in fact the localized size distribution of particle diame- ters inside the spray, which dictates the spray cast micro- structure and mechanical properties. In turn, local size distributions depend on the break up mechanisms. The latter, have received considerable attention in earlier phenomenological studies [4-14] in respect to atomiza- tion parameters – such as nature of the gas and melt phase, gas injection pressures and melt superheat. More recently, experimental treatises of atomizing geometries have been presented [15-16]. Liquid break up phenomena, however – although described in the macro scale early on
Show more

10 Read more

Treatment of sugar industry effluent using electrocoagulation process: Process optimization using response surface methodology

Treatment of sugar industry effluent using electrocoagulation process: Process optimization using response surface methodology

Sugar industries are one of the most important agro based industries and its contribution in economy is more in many countries. Brazil, India, European Union, Thailand, China, United State, Pakistan, Russia, Mexico and Australia are main sugar producing countries in the world. Total contributions by these countries are about 150 million metric tons in the year 2017-2018. 1 Sugar is produced by sugar beet and sugarcane out of which contribution of sugarcane is more than 70 %. The polluted water produced by sugarcane based sugar industry- es are more complex as compared to sugar beet based. 2 In sugarcane based sugar
Show more

19 Read more

Point observations of liquid water content in wet snow – investigating methodical, spatial and temporal aspects

Point observations of liquid water content in wet snow – investigating methodical, spatial and temporal aspects

Abstract. Information about the volume and the spatial and temporal distribution of liquid water in snow is impor- tant for forecasting wet snow avalanches and for predicting melt-water run-off. The distribution of liquid water in snow is commonly estimated from point measurements using a “hand” squeeze test, or a dielectric device such as a “Snow Fork” or a “Denoth meter”. Here we compare estimates of water content in the Swiss Alps made using the hand test to those made with a Snow Fork and a Denoth meter. Measure- ments were conducted in the Swiss Alps, mostly above tree line; more than 12 000 measurements were made at 85 loca- tions over 30 days. Results show that the hand test generally over estimates the volumetric liquid water content. Estimates using the Snow Fork are generally 1 % higher than those de- rived from the Denoth meter. The measurements were also used to investigate temporal and small-scale spatial patterns of wetness. Results show that typically a single point mea- surement does not characterize the wetness of the surround- ing snow. Large diurnal changes in wetness are common in the near-surface snow, and associated changes at depth were also observed. A single vertical profile of measurements is not sufficient to determine whether these changes were a re- sult of a spatially homogeneous wetting front or caused by in- filtration through pipes. Based on our observations, we sug- gest that three measurements at horizontal distances greater than 50 cm are needed to adequately characterize the distri- bution of liquid water through a snowpack. Further, we sug- gest a simplified classification scheme that includes five wet- ness patterns that incorporate both the vertical and horizontal distribution of liquid water in a snowpack.
Show more

14 Read more

The effect of droplet size and liquid water content on ice accretion and aerodynamic coefficients of tower legs

The effect of droplet size and liquid water content on ice accretion and aerodynamic coefficients of tower legs

An experimental study was conducted to examine the effects of varying the cloud characteristics on ice accretion on tower legs and on the aerodynamic coefficients around the ice-covered legs. First, the variations of droplet size distribution (DSD) and liquid water content (LWC) in vertical and streamwise directions were measured. Then, variations of ice accretion on an angle bar in the same direction as the flow were measured to determine the aerodynamic forces on a tower leg as a function of ice accretion. The ice accretion experiments were carried out under two conditions with different LWCs and air velocities. The drag coefficient was calculated with different masses and ice shapes for the angle bar as obtained in the experiments. The results showed a reduction in the drag coefficient in the vertical direction with increased local LWC and thicker ice accumulation.
Show more

20 Read more

Show all 10000 documents...