scholarly journals Mechanistic modeling of pesticide uptake with a 3D plant architecture model

2021 ◽  
Author(s):  
Helena Jorda ◽  
Katrin Huber ◽  
Asta Kunkel ◽  
Jan Vanderborght ◽  
Mathieu Javaux ◽  
...  
Keyword(s):  
Root Zone ◽  
Chemical Properties ◽  
Mechanistic Modeling ◽  
The European Union ◽  
Architecture Model ◽  
Single Root ◽  
Solute Uptake ◽  
Physical And Chemical ◽  
And Diffusion ◽  
Good Agreement

Abstract A new root solute uptake model based on a lumped version of the Trapp model (Trapp, 2000) was implemented in a coupled version of R-SWMS-ParTrace models for 3-D water flow and solute transport in soil and roots. Solute uptake was modeled as two individual processes: advection with the transpiration stream and diffusion through the root membrane. We parameterized the model for a FOCUS scenario used in the European Union for pesticide registration. Simulation with a single root showed a good agreement with the results produced by the 1D PEARL model. Simulations with a complex root system predicted larger water uptake from the upper root zone, leading to larger pesticide uptake when pesticides are concentrated in the upper root zone. Dilution of root water concentrations at the top root zone with water with low pesticide concentration taken up from the bottom of the root zone lead to larger uptake of solute when uptake was simulated as a diffusive process. This illustrates the importance of modeling uptake mechanistically and considering root and solute physical and chemical properties, especially when root-zone pesticide concentrations are non uniform.

scholarly journals Mechanistic modeling of pesticide uptake with a 3D plant architecture model

2021 ◽  
Author(s):  
Helena Jorda ◽  
Katrin Huber ◽  
Asta Kunkel ◽  
Jan Vanderborght ◽  
Mathieu Javaux ◽  
...  
Keyword(s):  
Root Zone ◽  
Mechanistic Model ◽  
Chemical Properties ◽  
Mechanistic Modeling ◽  
The European Union ◽  
Architecture Model ◽  
Solute Uptake ◽  
Uptake Process ◽  
Set Up ◽  
Pesticide Registration

AbstractMeaningful assessment of pesticide fate in soils and plants is based on fate models that represent all relevant processes. With mechanistic models, these processes can be simulated based on soil, substance, and plant properties. We present a mechanistic model that simulates pesticide uptake from soil and investigate how it is influenced, depending on the governing uptake process, by root and substance properties and by distributions of the substance and water in the soil profile. A new root solute uptake model based on a lumped version of the Trapp model (Trapp, 2000) was implemented in a coupled version of R-SWMS-ParTrace models for 3-D water flow and solute transport in soil and root systems. Solute uptake was modeled as two individual processes: advection with the transpiration stream and diffusion through the root membrane. We set up the model for a FOCUS scenario used in the European Union (EU) for pesticide registration. Considering a single vertical root and advective uptake only, the root hydraulic properties could be defined so that water and substance uptake and substance fate in soil showed a good agreement with the results of the 1D PEARL model, one of the reference models used in the EU for pesticide registration. Simulations with a complex root system and using root hydraulic parameters reported in the literature predicted larger water uptake from the upper root zone, leading to larger pesticide uptake when pesticides are concentrated in the upper root zone. Dilution of root water concentrations at the top root zone with water with low pesticide concentration taken up from the bottom of the root zone leads to larger uptake of solute when uptake was simulated as a diffusive process. This illustrates the importance of modeling uptake mechanistically and considering root and solute physical and chemical properties, especially when root-zone pesticide concentrations are non-uniform.

scholarly journals Raman and Fluorescence Spectroscopy of CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jianlan Cui ◽  
Gregory A. Hope
Keyword(s):  
Rare Earth ◽  
Energy Levels ◽  
Fluorescence Emission ◽  
Chemical Properties ◽  
Rare Earth Oxide ◽  
Raman Shift ◽  
Laser Sources ◽  
Induced Changes ◽  
Physical And Chemical ◽  
Good Agreement

To better understand and ascertain the mechanisms of flotation reagent interaction with rare earth (RE) minerals, it is necessary to determine the physical and chemical properties of the constituent components. Seven rare earth oxides (CeO2, Er2O3, Nd2O3, Tm2O3, Yb2O3, La2O3, and Tb4O7) that cover the rare earth elements (REEs) from light to heavy REEs have been investigated using Raman spectroscopy. Multiple laser sources (wavelengths of 325 nm, 442 nm, 514 nm, and 632.8 nm) for the Raman shift ranges from 100 cm−1to 5000 cm−1of these excitations were used for each individual rare earth oxide. Raman shifts and fluorescence emission have been identified. Theoretical energy levels for Er, Nd, and Yb were used for the interpretation of fluorescence emission. The experimental results showed good agreement with the theoretical calculation for Er2O3and Nd2O3. Additional fluorescence emission was observed with Yb2O3that did not fit the reported energy level diagram. Tb4O7was observed undergoing laser induced changes during examination.

scholarly journals Determination of physiochemical properties of Gum Arabic as a suitable binder in emulsion house paint

2016 ◽  
Vol 5 (1) ◽  
pp. 67-78
Author(s):  
Ali L. Yaumi ◽  
Ahmed M. Murtala ◽  
Habiba D. Muhd ◽  
Fatima M. Saleh
Keyword(s):  
Chemical Properties ◽  
Gum Arabic ◽  
Acacia Senegal ◽  
Physiochemical Properties ◽  
Binding Strength ◽  
Wide Range ◽  
Percentage Concentration ◽  
Physical And Chemical ◽  
Good Agreement

Gum Arabic “GA” is an organic adhesive produced from a tree called named Acacia Senegal. The gum has a wide range of industrial uses, especially in areas of feeds, textiles, and pharmaceuticals. It is used as emulsifier and serves mostly as stabilizer in both cosmetic and food products which contains oil water interface. GA sample was collected, formulated and prepared into various concentrations ranging from 20%w/v to 85%w/v. The quality and applicability of well characterized materials are directly related to their physical and chemical properties. From the physiochemical analysis, the result revealed that all the samples were slightly acidic (pH ranging from 4.81-6.41). This range is in good agreement with reported pH values for gum arabic and other Acacia gums by several authors. . The binding strength increases as the number of days increases for example in sample F (50%w/v) gum Arabic concentration increases from 1.5 in the 1st day to 1.97 in the 28th day. The samples prepared are denser than water which indicates that the density increases as the percentage concentration of the samples increases and the relative density of the gum solution is independent on time. The binding strength of sample G (75%w/v) gum concentration compared well to that of polyvinyl acetate (PVA). International Journal of Environment Vol. 5 (1) 2016,  pp: 67-78

scholarly journals Calculation of evapotranspiration from potatoes.

1969 ◽  
Vol 17 (4) ◽  
pp. 283-299
Author(s):  
G. Endrodi ◽  
P.E. Rijtema
Keyword(s):  
Soil Cover ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Sprinkler Irrigation ◽  
Growing Season ◽  
Diffusion Resistance ◽  
Derived Relations ◽  
Moisture Extraction ◽  
And Diffusion ◽  
Good Agreement

Data from sprinkler irrigation experiments with potatoes were used to calculate the actual and potential evapotranspiration from the crop during the growing season, using standard meteorologie data. During the experiments the moisture extraction from the effective root zone was determined by soil sampling. The water-use by the crop for the different periods was also derived from the water balance and both values were in good agreement in periods without extreme conditions of precipitation, this showing that the derived relations between crop height and surface roughness, between soil cover, light intensity, crop characteristics, soil characteristics and diffusion resistance, and between maturation and internal plant resistance were reasonably established. F.s.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Calculation and Analysis of the Thermophysical Parameters of Micro-Emulsified Ethanol-Diesel Blended Fuel

2012 ◽  
Vol 271-272 ◽  
pp. 121-125 ◽  
Author(s):  
Peng Hu ◽  
Ping Sun ◽  
Hai Qiang Ning ◽  
De Qing Mei
Keyword(s):  
Chemical Properties ◽  
Diesel Oil ◽  
Empirical Formulas ◽  
Thermophysical Parameters ◽  
Harmful Emissions ◽  
Blended Fuel ◽  
Temperature And Pressure ◽  
Physical And Chemical ◽  
Blended Fuels ◽  
And Diffusion

The micro-emulsified ethanol-diesel blended fuel is an ideal alternative oxygenous fuel for diesel engines due to its physical and chemical properties and excellent combustion characteristics. Fueled with this fuel, a diesel engine can give off remarkably lower harmful emissions,especially particulate. It is necessary to take into account instantaneous variations of the thermophysical parameters of blended fuels with temperature and pressure. For these reasons, this paper use the empirical formulas calculates the thermophysical parameters of this blended fuel，including the specific heat capacity, viscosity, thermal conductivity and diffusion coefficient. And the effects of the temperature, pressure and ethanol content on the initial blended fuel’s condition are investigated. The results show that the addition of some ethanol to the diesel oil can contribute to the evaporation of the micro-emulsified ethanol-diesel blended fuel, and these empirical formulas are able to be employed to calculate the thermophysical parameters of this blended fuel.

Recent studies chemical sensors based on phthalocyanines

2009 ◽  
Vol 13 (11) ◽  
pp. 1179-1187 ◽  
Author(s):  
Zafer Ziya Öztürk ◽  
Necmettin Kılınç ◽  
Devrim Atilla ◽  
Ayşe Gül Gürek ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Chemical Properties ◽  
Sensing Properties ◽  
Sensor Performance ◽  
Chemical Recognition ◽  
Linear Sorption ◽  
Sorption Energy ◽  
Physical And Chemical ◽  
Gas Response ◽  
Good Agreement

Phthalocyanines (Pcs) are organic compounds able to act as chemical recognition systems because of the various physical effects induced in them by interaction with a large number of gases. The gas response, stability and other sensing characteristics of the Pc films are affected by many factors, such as film morphology, molecular orientation and so on. The interaction between the Pc coatings and the gas molecules may be classified in terms of irreversible chemical affinity, reversible (usually charge transfer) chemical reaction or sorption. The nature of the interactions between the coating and vapor molecules determines the selectivity, sensitivity, signal kinetics, and the reversibility of the sensor. The magnitude of these interactions may be conveniently described in the frame of the linear sorption energy relationship (LSER) model that has been shown to be very efficient at predicting the behavior of polymer-based sensors. In this paper, the effect of coating parameters on sensing properties and sensing mechanism are reviewed. We have proposed an alternative way to achieve optimal sensor performance: liquid crystalline Pcs forming self-ordered thin films of defined area and thickness simply by heating the sample over the phase transition temperature and synthetized mesomorphic and functionalized phthalocyanines, to develop sensors based on mass-sensitive transducers (quartz crystal microbalance, QCM). Phthalocyanines used are discussed in terms of their physical and chemical properties, as well as their sensing properties: sensitivity, selectivity and reversibility. We showed our results with LSER and the results are in good agreement with this theory.

scholarly journals Performance and Emissions of Diesel Engine Using Bio-Fuel Derived From Waste Fish Oil

2012 ◽  
Author(s):  
Nadia Mrad ◽  
Fethi Aloui ◽  
Mohand Tazerout
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Chemical Properties ◽  
Diffusion Combustion ◽  
Brake Thermal Efficiency ◽  
Combustion Duration ◽  
Performance And Emissions ◽  
Cracking Process ◽  
Physical And Chemical ◽  
And Diffusion

In the present work, waste fish fat from fish processing industry is considered as an energy source for diesel engines. In this regard, catalytic cracking process is considered for this present study. The physical and chemical properties of biofuel are very close to diesel fuel. The experiments were conducted in a single cylinder diesel engine to study the performance, emission and combustion characteristics of biofuel. As a result, fuel undergoes good combustion and hence there is significant improvement in performance and reduction in emissions. Experimental results indicate a marginal increase in brake thermal efficiency at all loads compared to diesel fuel. The results show that despite of high NOx and CO2, the engine has lesser UHC, CO and PM than standard diesel fuel. The premixed and diffusion combustion duration is decreased with biofuel compared to diesel fuel. The engine was running smooth at all load conditions with biofuel. It is concluded that the biofuel derived from waste fish fat can be consider as a substitute for diesel fuel.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

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