scholarly journals Spreading of chemical substance after its accidental spillage onto the soil surface under unsaturated conditions and variable porosity

2019 ◽  
pp. 41-44
Author(s):  
Olena Kozhushko ◽  
Petro Martyniuk
Keyword(s):  
Mathematical Model ◽  
Soil Moisture ◽  
Soil Profile ◽  
Moisture Transport ◽  
Soil Surface ◽  
Chemical Substance ◽  
High Concentration ◽  
Solute Transfer ◽  
Variable Porosity ◽  
The One

In this paper we study a mathematical model of soil moisture transport with variable porosity. The problem is set for the case of highly concentrated solute spilled onto soil surface. We investigate the way solute transfer, adsorption of contaminant by soil particles and variable porosity influence infiltration of solute into the soil profile. For that purpose, two models are used: a classical one and the one with consideration of mentioned factors. By comparing the results of both models, we established that high concentration of solute causes moisture transport to transpire more slowly, and the pollutant to remain on the soil surface for longer time. Numerical results indicate that porosity can vary considerably under the conditions of intensive contamination with salts.

scholarly journals Optimizing the Positioning of Soil Moisture Monitoring Sensors in Winter Wheat Fields

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1707
Author(s):  
Xiaojun Shen ◽  
Jing Liang ◽  
Ketema Zeleke ◽  
Yueping Liang ◽  
Guangshuai Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Winter Wheat ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Profile ◽  
Root Distribution ◽  
Soil Surface ◽  
Soil Moisture Sensors ◽  
Total Average

Collecting accurate real-time soil moisture data in crop root zones is the foundation of automated precision irrigation systems. Soil moisture sensors (SMSs) have been used to monitor soil water content (SWC) in crop fields for a long time; however, there is no generally accepted guideline for determining optimal number and placement of soil moisture sensors in the soil profile. In order to study adequate positioning for the installation of soil moisture sensors in the soil profile, six years of field experiments were carried out in North China Plain (NCP). Soil water content was measured using the gravimetric method every 7 to 10 days during six growing seasons of winter wheat (Triticum aestivum L), and root distribution was measured using a soil core method during the key periods of winter wheat growth. The results from the experimental data analysis show that SWC at different depths had a high linear correlation. In addition, the values of correlation coefficients decreased with increasing soil depth; the coefficient of variation (CV) of SWC was higher in the surface layers than in the deeper layers (depths were 0–40 cm, 0–60 cm, and 0–100 cm during the early, middle, and last stages of winter wheat, respectively); wheat roots were mainly distributed in the surface layer. According to an analysis of CV for SWC and root distribution, the depths of planned wetted layers were determined to be 0–40 cm, 0–60 cm, and 0–100 cm during the sowing to reviving stages (the early stage of winter wheat), returning green and jointing stages (the middle stage of winter wheat), and heading to maturity stage (the last stage of winter wheat), respectively. The correlation and R-cluster analyses of SWC at different layers in the soil profile showed that SMSs should be installed 10 and 30 cm below the soil surface during the winter wheat growing season. The linear regression model can be built using SWC at depths of 10 and 30 cm to predict total average SWC in the soil profile. The results of validation showed that the developed model provided reliable estimates of total average SWC in the planned wetted layer. In brief, this study suggests that suitable positioning of soil moisture sensors is at depths of 10 and 30 cm below the soil surface.

scholarly journals Mathematical Model for Reducing the Concentration of a Chemical Substance Applicable in the Procedures of Plasmatic Treatment

2019 ◽  
Vol 70 (4) ◽  
pp. 1298-1301
Author(s):  
Ciprian Mihai Gindac ◽  
Ovidiu Horea Bedreag ◽  
Laura Alexandra Nussbaum ◽  
Iulia Bianca Micu Serbu ◽  
Roxana Folescu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Laboratory Data ◽  
Chemical Substance ◽  
The Body ◽  
Chemical Model ◽  
Mathematical Form ◽  
Initial Concentration ◽  
Plasma Loss ◽  
The One ◽  
The Mathematical Model

The objective was to study the correlation between the mathematical form of a chemical that we want to lower its initial concentration by the regressive method and the purging of the body�s toxic present chemicals that need to be eliminated. We developed a chemical model, by which, to a given volume, with a certain (X - concentration %) dissolved substance in a container, the initial solvent, without solvit, is added (concentration 0%) with an equal rhythm to the one that is lost from the used container. The solution that will be lost will contain less and less concentrations of solvit, compared to the initial value X%. At the same time, the concentration of our chemical model will decrease. We applied a regressive mathematical formula to this model in order to calculate the concentration in the container in each moment. At the same time, we conducted treatment sessions in patients in which certain substances need to be eliminated, a procedure that complies with the described chemical model. We have demonstrated that at the same volume of 0% solvit wash, the substance purging with X% concentration is more effective, if the procedure starts with an initial loss of concentrated substance, with ulterior volume replacement. Laboratory data confirms the mathematical model in patients who started the procedure with plasma loss. The developed chemical model demonstrates that the initial loss of substance, hastens the decrease of the initial concentration, especially as the loss is higher at the beginning of the procedure if we use the same replacement volume without the substance in the initial solution. This model can be applied in plasma treatment methods in order to study the patient�s safety and the amount of plasma the patient can lose at the beginning.

SOIL MOISTURE GRADIENT HYDROMETER

2020 ◽  
pp. 44-47
Author(s):  
A.E. KASYANOV ◽  
◽  
D.D. KOBOZEV ◽  
ISMAIL KHEBA
Keyword(s):  
Soil Moisture ◽  
Measurement Error ◽  
Soil Profile ◽  
Soil Surface ◽  
Digital Voltmeter ◽  
Humidity Sensors ◽  
Moisture Meter ◽  
Weight Method ◽  
Side Walls ◽  
The Stability

There is proposed the design of a gradient soil moisture meter which includes humidity sensors placed along the horizons of the soil profile, it registers humidity in some soil layers,and it is tested under field conditions. The moisture meter consists of a case, contact block, lead cables, battery, digital voltmeter and capacitive humidity sensors. The contact block is located in the neck of the case, cables are inside the case and capacitive sensors are placed horizontally along the layers of the soil profile. The battery and digital voltmeter are connected to the contact block and placed on the soil surface. The device is installed vertically in the corner of the soil section. The device is installed vertically in the corner of the soil section. Humidity sensors are embedded in the side walls of the section. The device case and all cable connections to the case are sealed. During the field test there was arranged a flood site around the device, the soil was saturated up to the full moisture capacity and the indicators were calibrated: soil moisture – the voltage of the analog outputs. In parallel, the soil moisture was measured by the thermostatic-weight method. The humidity measurement error did not change for two weeks. The efficiency of the proposed design of the moisture meter is confirmed. The stability of the moisture meter was established within 3 weeks with a relative measurement error of 2 … 3%. The moisture meter is installed in the soil for the whole growing season.

scholarly journals Some Preliminary Notes on the Physical Properties of the Soils of the Ganges Valley, more especially in their relation to Soil Moisture

1906 ◽  
Vol 1 (4) ◽  
pp. 454-469 ◽  
Author(s):  
H. M. Leake
Keyword(s):  
Soil Moisture ◽  
Physical Properties ◽  
Short Duration ◽  
Irrigation Water ◽  
The Other ◽  
Indian Agriculture ◽  
Northern India ◽  
The One ◽  
The Ganges

In a stretch of arable lands like those of the Ganges Valley, although damage may be caused by occasional floods, which are sudden and of short duration, the more general, and by far the most serious loss is due to deficiency of moisture of the soil: thus the relation of the soil to soil moisture becomes of more than ordinary importance. Dr Voelcker, in his Report on Indian Agriculture, remarks: “In India the relation of soils to moisture acquires a greater significance than almost anywhere else.......” This relation is fundamental, for on it depends the methods for the conservation of soil moisture, for the economical application of irrigation water, and for the treatment of barren and salt lands—all problems of direct interest to agriculturists in the plains of Northern India. The methods for dealing with these problems must be largely—if not entirely—empirical until such time as the behaviour of the soil in its relation to moisture is investigated. The problem in all its various branches is enormous, and in a country in which the seasons follow each other with such rapidity, and vary the one from the other in so marked a manner, it frequently happens that a particular point, if not determined within a period of a few days, must await solution until the following year.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

scholarly journals High concentration Brownian coagulation in jet flow using two enhancement formulations

2012 ◽  
Vol 16 (5) ◽  
pp. 1519-1523
Author(s):  
Pei-Feng Lin ◽  
Di-Chong Wu ◽  
Ze-Fei Zhu
Keyword(s):  
Volume Fraction ◽  
Taylor Series Expansion ◽  
Expansion Method ◽  
High Volume ◽  
Jet Flow ◽  
High Concentration ◽  
Brownian Coagulation ◽  
Planar Jet ◽  
Ultra Fine Particle ◽  
The One

Ultra-fine particle coagulation by Brownian motion at high concentration in planar jet flow is simulated. A Taylor-Series Expansion Method of Moments is employed to solve the particle general dynamic equation. The volume fraction gets high value, very closes to that at the nozzle exit. As the vortex pairing develops, the high volume fraction region rolls out and mixes with the low value region. The enhancement factor given by Trzeciak et al. will be less than one at some specific outer positions, which seems to be less accurate than the one given by Heine et al.

INBORN ERROR OF HISTIDINE METABOLISM

PEDIATRICS ◽  
1962 ◽  
Vol 29 (5) ◽  
pp. 714-728
Author(s):  
H. Ghadimi ◽  
M. W. Partington ◽  
A. Hunter
Keyword(s):  
Ferric Chloride ◽  
Urocanic Acid ◽  
High Concentration ◽  
Normal Children ◽  
Total Lack ◽  
Normal Urine ◽  
One Year ◽  
The One ◽  
Blue Eyes ◽  
Derivatives Of

A 3-year-old girl with fair hair and blue eyes came under observation because of speech retardation. The patient was given a phenylalanine-free diet, since persistently positive urine tests with ferric chloride and reagent strips (Phenistix) were strongly suggestive of phenylketonuria. On further investigation she was found to be suffering from a totally different and not heretofore recognized condition, the salient features of which were an abnormally high concentration of histidine in the blood and an excessive output of histidine in the urine. The child's sister, one year older, presented the same metabolic anomaly. In each case both the concentration of histidine in plasma and the daily output were directly related to the amount of protein in the diet; but even at their lowest levels they greatly exceeded those of normal children of the same age. An oral load of histidine was followed by an increase of histidine in plasma much higher and more prolonged than that observed in controls, and by the excretion of a much larger fraction of the ingested dose. The urine of each sister contained not only excessive amounts of histidine but also notable quantities of imidazole-pyruvic, imidazole-acetic, and imidazole-lactic acid, histidine derivatives of which normal urine contains only traces. It is concluded that in the two sisters the normally predominant pathway of histidine catabolism, which leads through urocanic acid to glutamic acid, was partially or completely blocked. Since, even after histidine loading, the urines never contained detectable amounts of urocanic acid, the block must precede the formation of that substance. The condition presented is therefore due primarily to a deficiency or total lack of histidine-alpha-deaminase; the enzyme which converts histidine to urocanic acid. As a result of this defect histidine is forced to take the alternative but less efficient pathway which begins with its transamination to imidazole-pyruvic acid. This substance is the one responsible for positive reactions in the ferric chloride and Phenistix tests. All urine specimens examined, whether from the patient or from normal controls, contained considerable quantities of an unidentifiable imidazole compound ("X"), which does not appear to have been previously reported. The existence of this substance may call for some modification of current concepts of histidine metabolism in man.

scholarly journals Potential Applications of GNSS-R Observations over Agricultural Areas: Results from the GLORI Airborne Campaign

2018 ◽  
Vol 10 (8) ◽  
pp. 1245 ◽  
Author(s):  
Mehrez Zribi ◽  
Erwan Motte ◽  
Nicolas Baghdadi ◽  
Frédéric Baup ◽  
Sylvia Dayau ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Signal To Noise Ratio ◽  
Soil Surface ◽  
Satellite System ◽  
Area Index ◽  
Vegetation Height ◽  
Study Sites ◽  
Global Navigation Satellite ◽  
Vegetation Characteristic ◽  
Agricultural Areas

The aim of this study is to analyze the sensitivity of airborne Global Navigation Satellite System Reflectometry (GNSS-R) on soil surface and vegetation cover characteristics in agricultural areas. Airborne polarimetric GNSS-R data were acquired in the context of the GLORI’2015 campaign over two study sites in Southwest France in June and July of 2015. Ground measurements of soil surface parameters (moisture content) and vegetation characteristics (leaf area index (LAI), and vegetation height) were recorded for different types of crops (corn, sunflower, wheat, soybean, vegetable) simultaneously with the airborne GNSS-R measurements. Three GNSS-R observables (apparent reflectivity, the reflected signal-to-noise-ratio (SNR), and the polarimetric ratio (PR)) were found to be well correlated with soil moisture and a major vegetation characteristic (LAI). A tau-omega model was used to explain the dependence of the GNSS-R reflectivity on both the soil moisture and vegetation parameters.

Sign in / Sign up

Export Citation Format

Share Document