scholarly journals Influence of Water Content on Biofiltration Performance

2011 ◽  
Vol 10 (2) ◽  
pp. 31 ◽  
Author(s):  
Daisy B Badilla ◽  
Peter A Gostomski ◽  
Maria Lourdes P Dalida
Keyword(s):  
Water Content ◽  
Dry Weight ◽  
Full Scale ◽  
Elimination Capacity ◽  
Water Retention Curve ◽  
Matric Potential ◽  
Influence Of Water ◽  
Growth Activity ◽  
Maximum Elimination Capacity ◽  
Filter Bed

In biofiltration, contaminants in a gas stream are transferred into a biofilm on the filter bed medium and are metabolized by the microorganisms. Water is essential for microbial growth/activity and for transport of nutrients. In both full-scale and laboratory-scale systems, the water content of the medium is difficult to control. In this study, a biofilter, with rigorous water content control and internal gas recycle, was used to determine the influence of the water content on the degradation of toluene. Soil was used as the medium for treating toluene-contaminated air at an average inlet concentration of 263 ppm and a flow rate of 21 ml min-1. Through a water retention curve, gravimetric water content was related to matric potential. Results showed that lowering the water content from 79 to 48% (dry weight) or -20 to -400 cm H2O matric potential decreased the elimination capacity (EC) by 42% (29.8 to 17.3 g m-3h-1). Wetting the medium by increasing the matric potential from -400 to -10 cm H2O increased the elimination capacity to 43.9 g m-3h-1. However, further increase of the matric potential from -10 to -5 cm H2O decreased the elimination capacity by 57% (43.9 to 19.0 g m-3 h-1). Thus, this study suggests the soil water content should be controlled at about 96% (dry weight) or a matric potential of -10 cm H2O and the maximum elimination capacity is restricted to a narrow water content/matric potential. This narrow range impacts on the operation of full-scale biofilters as traditional techniques for water content control would make maintaining this range difficult.

scholarly journals A Novel Frequency Domain Impedance Sensor with a Perforated Cylinder Coaxial Design for In-Situ Measuring Soil Matric Potential

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2626 ◽  
Author(s):  
Chao Chen ◽  
Xiaofei Yan ◽  
Qiang Xu ◽  
Song Yu ◽  
Yihan Ma ◽  
...  
Keyword(s):  
Water Content ◽  
Water Retention ◽  
Soil Samples ◽  
Environmental Research ◽  
Water Retention Curve ◽  
The Novel ◽  
Soil Matric Potential ◽  
Matric Potential ◽  
Retention Curve

Soil matric potential is an important parameter for agricultural and environmental research and applications. In this study, we developed a novel sensor to determine fast and in-situ the soil matric potential. The probe of the soil matric potential sensor comprises a perforated coaxial stainless steel cylinder filled with a porous material (gypsum). With a pre-determined gypsum water retention curve, the probe can determine the gypsum matric potential through measuring its water content. The matric potential of soil surrounding the probe is inferred by the reading of the sensor after the soil reaches a hydraulic equilibrium with the gypsum. The sensor was calibrated by determining the gypsum water retention curve using a pressure plate method and tested in three soil samples with different textures. The results showed that the novel sensor can determine the water retention curves of the three soil samples from saturated to dry when combined with a soil water content sensor. The novel sensor can respond fast to the changes of the soil matric potential due to its small volume. Future research could explore the application for agriculture field crop irrigation.

scholarly journals Changes on diametral compression behaviour of compacted marls due to drying

2020 ◽  
Vol 195 ◽  
pp. 03008
Author(s):  
Carmen Covadonga Garcia-Fernandez ◽  
Rafaela Cardoso ◽  
Martina Inmaculada Alvarez-Fernandez ◽  
Celestino Gonzalez-Nicieza
Keyword(s):  
Tensile Strength ◽  
Water Content ◽  
Degree Of Saturation ◽  
Water Retention Curve ◽  
Tensile Behaviour ◽  
Compression Tests ◽  
Diametral Compression ◽  
Earth Structures ◽  
Influence Of Water ◽  
Brazilian Splitting

Cracking due to desiccation can compromise the behaviour of earth structures built with compacted clayey soils by promoting water access and consequent volume changes on further wetting. Tensile strength therefore is important to be considered when studying the behaviour of such structures, and in particular its dependence on the degree of saturation or water content. The influence of water content in tensile behaviour of compacted marls was investigated by performing diametral compression tests (Brazilian splitting tests), where axial deformations were measured besides strength. The samples were prepared by compaction at optimum point using standard compaction energy (optimum water content 16%) and then dried by vapour equilibrium to reach water contents between 5% and 16%. The correspondence between water content and suction was done by using the drying branch of the water retention curve, measured using WP4 equipment (Water Dewpoint Potentiometer). Good relationships were found between tensile strength and the water content (and suction). In addition, the study was completed with the analysis of other parameters such as the semi-contact angle created in the loaded area and the stiffness of the material, which also showed changes with water content.

Influence of Water Deficits on the Water Relations Characteristics and Productivity of Wild and Cultivated Sunflowers

1983 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
MA Sobrado ◽  
NC Turner
Keyword(s):  
Water Stress ◽  
Water Content ◽  
Water Relations ◽  
Dry Matter ◽  
Weight Ratio ◽  
Dry Weight ◽  
Dry Matter Accumulation ◽  
Water Deficits ◽  
Influence Of Water ◽  
In The Wild

The effects of water deficits on the water relations characteristics and yield of two cultivated Helianthus annuus L. lines, Hysun 31 and Seneca, and two wild Helianthus species, H. nuttallii and H. petiolaris, were compared. The study was conducted on frequently irrigated and unirrigated plants growing in the field during the summer. Predawn measurements of leaf water potential and relative water content showed that, in the uninigated plants, water deficits increased in all species during the first month after sowing (period I), were relieved by rain in the second month (period II), and then increased progressively in the final month (period III). The osmotic potential at full turgor of unirrigated plants, estimated by pressure-volume curves, decreased by 0.12-0.22 MPa during periods I and III in the cultivated sunflowers, but did not decrease significantly in the wild sunflowers. Except in the irrigated Hysun 31 and Seneca during period I, the apoplastic water content was about 20% in all species and treatments. During period I, the turgid weight: dry weight ratio decreased significantly with water stress, particularly in the cultivated sunflowers; the changes were less marked in the wild sunflowers and during period III. Additionally, the turgid weight: dry weight ratio in the imgated cultivated sunflowers decreased throughout the season. The volumetric modulus of elasticity was similar among species and did not change with water stress or plant age. Dry matter accumulation was smaller in the wild species than in the cultivated lines; water stress reduced shoot dry matter similarly in all species. However, water deficits significantly reduced the seed yield only in Hysun 31 and Seneca.

Osmotic adjustment in leaves of Brassica oilseeds in response to water deficit

2006 ◽  
Vol 86 (2) ◽  
pp. 389-397 ◽  
Author(s):  
D. Levy ◽  
E. Fogelman ◽  
Y. Itzhak ◽  
Q. Ma ◽  
D. W. Turner ◽  
...  
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Osmotic Adjustment ◽  
Doubled Haploids ◽  
Sugar Content ◽  
Indian Mustard ◽  
Dry Weight ◽  
Soluble Solids ◽  
Influence Of Water

The influence of water deficit on water content (WC), total soluble solids (TSS), osmotic potential (OP), sugar content and osmotic adjustment (OA) of expanded and partly expanded leaves of Brassica oilseeds was examined. Nine canola (B. napus) cultivars (Karoo, Monty, Pinnacle, Hyden, Mystic, Rainbow, Surpass 300, Surpass 400, Surpass 501), two doubled haploids, one from Karoo (KDH) and the other from Monty (MDH) and one line of Indian mustard (B. juncea, PI-81792) were grown under glasshouse and net-house conditions. Expanded wilted leaves of Karoo and Monty absorbed excessive amounts of water per dry weight upon in vitro rehydration compared with control non-stressed leaves, resulting in underestimation of OA calculated on the basis of the relative water content (RWC). Hence, estimation of OA based on water weight per leaf dry weight (WC) was preferred. Young expanding leaves maintained visual turgor for 6-7 d after withholding irrigation, while expanded leaves on the same plants ceased to regain turgor overnight. The young expanding leaves exhibited greater accumulation of TSS and, consequently, more negative OPs compared with expanded leaves. Maintenance of OA after irrigation and turgor recovery was evident in both expanded and expanding leaves. Although OA under drought and upon turgor recovery varied within cultivars in different experiments, outstanding OA capacity, in terms of both magnitude and stability, was identified in the cultivar Hyden and in the doubled haploid of Monty, indicating the potential to select for this trait as well as to exploit variability for OA through haploidization. Key words: Brassica oilseeds, drought stress, osmotic adjustment, haploid lines

scholarly journals Evaluation of installation procedures of volumetric water content and matric potential probes: fundamentals for obtaining field and laboratory accordance

2021 ◽  
Vol 337 ◽  
pp. 01009
Author(s):  
Carnavale Thiago de Souza ◽  
Campos Tácio Mauro Pereira de ◽  
Lopes Haimon Diniz Alves
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Volumetric Water Content ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Matric Potential ◽  
Retention Curve ◽  
Double Ring ◽  
Hydraulic Equipment

The current paper aims to analyze the influence of installation procedures when it comes to the accordance of the Soil Water Retention Curve and field monitoring data. The method comprises testing three different installation procedures: with driving the rod into the soil; with the application of mud inside the auger hole; and with a hardened steel gauge. Further, is evaluated the influence of the variation of Bulk density on volumetric water content values by using the Proctor and a double ring hydraulic equipment. To analyze the soil-rod coupling, a microtomography imaging routine was performed. The results point out that the probe’s data are connected to the Bulk density of the material, producing higher volumetric water content values with the increase of Bulk density. Comparing results of different installation methods with laboratory results, it is possible to conclude that driving the rod directly into the soil is the best way to install the equipment since the probe underestimates the volumetric water content data by 2,5%, while the mud application by 4%, and the gauge method by 5%.

scholarly journals Integrating Moisture Characteristic Curves with Gravimetric Data in the Management of Substrate Moisture Content for Annual Vinca

HortScience ◽  
2018 ◽  
Vol 53 (8) ◽  
pp. 1197-1202
Author(s):  
Adam F. Newby ◽  
James E. Altland ◽  
Daniel K. Struve ◽  
Claudio C. Pasian ◽  
Peter P. Ling ◽  
...  
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
Leaf Area ◽  
Dry Weight ◽  
Sphagnum Moss ◽  
Matric Potential ◽  
Characteristic Curves ◽  
Root Dry Weight ◽  
Moisture Characteristic ◽  
Substrate Moisture

Greenhouse growers must use water more efficiently. One way to achieve this goal is to monitor substrate moisture content to decrease leaching. A systems approach to irrigation management would include knowledge of substrate matric potentials and air-filled pore space (AS) in addition to substrate moisture content. To study the relationship between substrate moisture and plant growth, annual vinca (Catharanthus roseus L.) was subject to a 2 × 2 factorial combination of two irrigation treatments and two substrates with differing moisture characteristic curves (MCCs). A gravimetric on-demand irrigation system was used to return substrate moisture content to matric potentials of −2 or −10 kPa at each irrigation via injected drippers inserted into each container. Moisture characteristic curves were used to determine gravimetric water content (GWC), volumetric water content (VWC), and AS at target substrate matric potential values for a potting mix consisting of sphagnum moss and perlite and a potting mix consisting of sphagnum moss, pine bark, perlite, and vermiculite. At each irrigation event, irrigation automatically shut off when the substrate-specific weight of the potted plants associated with the target matric potential was reached. Irrigation was triggered when the associated weight for a given treatment dropped 10% from the target weight. VWC and AS differed between substrates at similar matric potential values. Irrigating substrates to −2 kPa increased the irrigation volume applied, evapotranspiration, plant size, leaf area, shoot and root dry weight, and flower number per plant relative to irrigating to −10 kPa. Fafard 3B had less AS than Sunshine LB2 at target matric potential values. Plants grown in Fafard 3B had greater leaf area, shoot dry weight, and root dry weight. Leachate fraction ranged from 0.05 to 0.08 and was similar across all treatment combinations. Using data from an MCC in conjunction with gravimetric monitoring of the container–substrate–plant system allowed AS to be determined in real time based on the current weight of the substrate. Closely managing substrate matric potential and AS in addition to substrate water content can reduce irrigation and leachate volume while maintaining plant quality and reducing the environmental impacts of greenhouse crop production.

An implicit model for soil thermal conductivity and matric potential

2021 ◽  
Author(s):  
Yili Lu ◽  
Tusheng Ren ◽  
Sen Lu ◽  
Robert Horton
Keyword(s):  
Thermal Conductivity ◽  
Water Content ◽  
Water Retention Curve ◽  
Soil Thermal Conductivity ◽  
Matric Potential ◽  
Retention Curve ◽  
Implicit Model ◽  
Loam Soil ◽  
Conductivity Curve ◽  
Content Range

<p>Soil thermal conductivity (λ) is affected by the energy status of water and is closely related to soil matric potential (h). In this study, a soil water retention curve and a soil thermal conductivity curve were linked via the critical point that separated the adsorption water and capillary water regimes. Based on existing water retention curve and a thermal conductivity curve models, we derived a new implicit mathematical formulation of the λ-h relationship. The λ-h relationship was valid for the entire water content range at room temperature. The new model parameter values for adsorption, capillarity and soil thermal conduction were optimized, and a linear relationship between critical water content and maximum adsorption capacity was established by fitting the SWRC and STCC models to measurements from eight soils. Laboratory evaluations using λ and h measurements on a loam soil and a clay loam soil showed that the new model well described observed values with coefficients of determination greater than 0.97. The implicit model can quantify λ-h behaviors for various soil textures over the entire water content range.</p>

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

Modeling the Influence of Water Content on Soil Vapor Extraction

2003 ◽  
Vol 2 (3) ◽  
pp. 368
Author(s):  
Hongkyu Yoon ◽  
Albert J. Valocchi ◽  
Charles J. Werth
Keyword(s):  
Water Content ◽  
Soil Vapor Extraction ◽  
Vapor Extraction ◽  
Influence Of Water
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