Basic Drift Research Articles

Possibilities to reduce drift by 75 percent in biocidal applications of insecticides with cannon sprayers

BackgroundInsecticides are applied on a large scale in the environment to control the oak processionary moth (Thaumetopoea processionea) for the protection of human health. Drift of the insecticides to non-target areas is a risk for the surrounding biodiversity. Since the habitats of the caterpillars are usually restricted to the treetops, the sprayers used to apply biocidal products must be able to transport the droplets over longer distances. Therefore, cannon sprayers are often used. In this study, spray drift in an oak avenue from a cannon sprayer with hydraulic atomisation was measured with two different nozzles. The aim of this study is to compare spray drift when using a cannon sprayer with different drift-reducing nozzles with cannon sprayers with pneumatic atomisation to find options to reduce drift to non-target areas.ResultsThe results show that compared to the basic drift values for biocidal products using a cannon sprayer with pneumatic atomisation, a cannon sprayer with ID-120-05 POM nozzles achieves a drift reduction of 75% and a classification in this reduction class. No drift reduction could be determined with a cannon sprayer with AirMix 110-05 nozzles.ConclusionsBetter knowledge of drift of biocidal products is of utmost urgency in order to be able to compare and classify the currently used technologies. When using a cannon sprayer, this study shows that specific drift values are recommended based on the type of atomisation, as droplet size is an important factor in reducing drift. By choosing the technology with the highest drift reduction, the drift of biocidal products into the environment can be minimised by 75%, thus ensuring a much better protection of the environment.

An adversarial learning approach to forecasted wind field correction with an application to oil spill drift prediction

Reanalysis wind fields are obtained by correcting the numerically forecasted wind fields based on observation data (i.e., either remote sensing or in-situ observations, or both). Although they are more accurate than forecasted wind fields, reanalysis wind fields tend to have time latencies because they can only be released after the observations are obtained. In order to produce accurate estimates of wind fields in a more timely manner, we develop an adversarial learning approach to correcting forecasted wind fields to be close to reanalysis wind fields. The adversarial learning approach is conducted by an adversarial ConvLSTM network (ACLN) framework that consists of a corrector and a discriminator. The corrector aims at comprehensively capturing both spatial and temporal characteristics of a sequence of forecasted wind fields and producing a corrected forecast wind field for the final field in the sequence. The discriminator tries to distinguish corrected forecast wind field from its corresponding reanalysis wind field. The training of ACLN is alternate between the corrector and the discriminator in an adversarial fashion. The adversarial training mechanism enhances the corrector’s representational power. Additionally, the corrector exploits a residual learning architecture that effectively learns the differences between forecasted wind fields and the corresponding reanalysis wind fields. In this scenario, the well trained corrector requires neither reanalysis wind fields nor observations such that it can correct forecasted wind fields in a timely manner. Furthermore, corrected forecast wind fields are employed for oil spill drift prediction. Extensive experiments validate the effectiveness of the proposed ACLN framework in forecasted wind field correction along with oil spill drift prediction. Compared with ECMWF numerical forecasts, the ACLN achieves an average reduction of 6.2%, 6.9%, and 10.6% in RMSE, MAE, and MAPE, respectively. Compared with a basic drift prediction method, the ACLN based prediction method reduces the error by about 5000 m in the Sanchi oil spill accident. The source codes are available at https://github.com/liyongqingupc/ACLN-WindFieldCorrection, providing a baseline for correcting forecasted wind fields.

Calculation of Basic Average Drift Characteristics of Free Electrons in a Metallic Conductor with Electric Current

The results of an approximate calculation of theaveraged values of speeds of vmz of a longi-tudinal drift of lone electrons, and of circular frequencies of ωmz change of longitudinal elec-tronic waves de Broglie and of lengths of λmz of longitudinal electronic waves de Broglie in the metal of round cylindrical conductor with an electric axial-flow current of conductivity of i0(t) of different kinds (permanent, variable, and impulsive) and amplitude-time parameters (ATP). The results of verification of the obtained calculation correlations for speeds of vmz drift of lone electrons and lengths of λmz of electronic de Broglie waves in the examined con-ductor demonstrate their validity and working capacity. The obtained data confirm the quan-tum-wave nature of the electric current of conductivity of the indicated kinds of i0(t) and of ATP in a metallic conductor.

Effect of ground motion directionality on seismic dynamic responses of monopile offshore wind turbines

The structural stability of offshore wind turbines is constantly being challenged in seismically active areas. This study investigated the effect of ground motion directionality on the seismic dynamic responses of monopile offshore wind turbines (MOWTs). A set of horizontal pairs of ground motions were applied to a 5 MW MOWT model. Two groups of time-domain simulations, including (1) the wind turbine parked in a calm sea subjected to earthquakes, and (2) the wind turbine during normal operation at the rated wind speed subjected to earthquakes, were performed to investigate the seismic responses of the MOWT. The results showed that the structural responses of the MOWT were significantly affected by the angle of ground motion incidence. The environmental wind and wave loads contributed to a basic drift to the response of the structure, and can mitigate or increase the effect of ground motion directionality. Dynamic analyses using bi-directional horizontal ground motion exciting the wind turbine in the fore-aft (FA) and side-to-side (SS) directions resulted in a significant underestimation of the structural responses. The aerodynamic damping amplified the effect of ground motion directionality, and increased the underestimation of the structural responses using the FA and SS bi-directional excitation.

Search and Rescue Applications: On the Need to Improve Ocean Observing Data Systems in Offshore or Remote Locations

Search and rescue (SAR) in remote maritime locations is a difficult mission. One of the limitations in these isolated regions is the low density of available oceanographic data for model validation. In order to examine the state of remote search and rescue a review of maritime search theory and advances was conducted. This included basic drift theory, leeway, available environmental data, and the current methods used by the United States Coast Guard for SAR operations. In particular the U.S. Coast Guard’s fourteenth district’s SAR case history was examined and it was found that 60% of SAR cases fall outside of areas that have high-resolution wind and current data, with only global scale model forecasts available. In addition, 2% of cases occurred in offshore waters ( > 12nm from land) and exceeded 36 hours in asset response time. Three SAR simulations were run off the coast of Oahu, Hawaii using the same wind data, but different surface current models. These simulations had extremely large (up to 12,000 km2) search areas, highlighting the need for solutions that narrow these expected areas.

Relativistic theory of particles in a scattering flow – I. Basic equations, diffusion, and drift

Relativistic theory of particles in a scattering flow – I. Basic equations, diffusion, and drift

A "Beheaded" TAML Activator: A Compromised Catalyst that Emphasizes the Linearity between Catalytic Activity and pKa.

Studies of the new tetra-amido macrocyclic ligand (TAML) activator [FeIII{(Me2CNCOCMe2NCO)2CMe2}OH2]- (4) in water in the pH range of 2-13 suggest its pseudo-octahedral geometry with two nonequivalent axial H2O ligands and revealed (i) the anticipated basic drift of the first pKa of water to 11.38 due to four electron-donating methyl groups alongside (ii) its counterintuitive enhanced resistance to acid-induced iron(III) ejection from the macrocycle. The catalytic activity of 4 in the oxidation of Orange II (S) by H2O2 in the pH range of 7-12 is significantly lower than that of previously reported TAML activators, though it follows the common rate law (v/[FeIII] = kIkII[H2O2][S]/(kI[H2O2] + kII[S]) and typical pH profiles for kI and kII. At pH 7 and 25 °C the rate constants kI and kII equal 0.63 ± 0.02 and 1.19 ± 0.03 M-1 s-1, respectively. With these new values for pKa, kI and kII establishing new high and low limits, respectively, the rate constants kI and kII were correlated with pKa values of all TAML activators. The relations log k = log k0 + α × pKa were established with log k0 = 13 ± 2 and 20 ± 4 and α = -1.1 ± 0.2 and -1.8 ± 0.4 for kI and kII, respectively. Thus, the reactivity of TAML activators across four generations of catalysts is predictable through their pKa values.

Two-dimensional analytical model of threshold voltage and drain current of a double-halo gate-stacked triple-material double-gate MOSFET

We have developed a two-dimensional analytical model for the channel potential, threshold voltage, and drain-to-source current of a symmetric double-halo gate-stacked triple-material double-gate metal---oxide---semiconductor field-effect transistor (MOSFET). The two-dimensional Poisson's equation is solved to obtain the channel potential. For accurate modeling of the device, fringing capacitance and effective surface charge are considered. The basic drift---diffusion equation is used to model the drain-to-source current. The midchannel potential of the device is used instead of the surface potential in the current modeling, considering the fact that the punch-through current is not confined only to the surface in a fully depleted MOSFET. An expression for the pinch-off voltage is derived to model the drain current in the saturation region accurately. Various short-channel effects such as drain-induced barrier lowering, gate leakage, threshold voltage, and roll-off have also been investigated. This structure shows excellent ability to suppress various short-channel effects. The results of the proposed model are validated against data obtained from a commercially available numerical device simulator.

Архитектура рынков: экономическая социология капиталистических обществ XXI века (перевод Александра Куракина)

Market societies have created more wealth and more opportunities for more people, than any other system of social organization in history. Yet we still have a rudimentary understanding of how markets themselves are social constructions that require extensive institutional support. This groundbreaking work seeks to fill this gap, to make sense of modern capitalism by developing a sociological theory of market institutions. Addressing the dynamism that capitalism brings with it, Neil Fligstein argues that the basic drift of any market and its actors is toward stabilization.“The Architecture of Markets” represents a major and timely step beyond recent, largely empirical studies that oppose the neoclassical model of perfect competition but provide sparse theory toward a coherent economic sociology. Fligstein offers this theory. His political-cultural approach explains why governments remain crucial to markets and why so many national variations of capitalism endure. States help make stable markets possible by, for example, establishing the rule of law and adjudicating the class struggle. State-building and market-building go hand in hand.Fligstein shows that market actors depend mightily upon governments and the members of society for the social conditions that produce wealth. He demonstrates that systems favoring more social justice and redis¬tribution can yield stable markets and economic growth as readily as less egalitarian systems. The journal publishes the chapter 9, «Globalisation», excerpt from «The Architecture of Markets» by Neil Fligstein. The author questions why increasing globalisation has not resulted in convergence of organisational forms at national level. In search of an answer to this puzzle, Fligstein uses the analytical tools of a politicalcultural approach. As the main tasks of the chapter the author considers the development of working definitions of globalisation and a review of arguments demonstrating that globalists exaggerate the scope of its impact on the organisation of production, the state’s role in providing for their citizens and social stratification.

Reliable extraction of organic solar cell parameters by combining steady-state and transient techniques

A method to extract reliable material and device parameters of organic solar cells is presented. We employ a comprehensive numerical device model to simulate the solar cell operation in transient and steady-state condition. Parameter extraction with numerical simulation is error-prone because model parameters are often correlated, their unique determination is very difficult and extracted parameters are likely to be inaccurate. We combine the current–voltage characteristics, the photo-CELIV currents (charge extraction with linearly increasing voltage) and the photocurrent response to a light pulse to reduce parameter correlation and increase accuracy and reliability of the extracted parameters. With a correlation matrix analysis it is shown that parameter correlation is significantly reduced when combining several experimental data sets compared with the analysis of current–voltage curves only. We find a set of parameters to reproduce the complete series of measurements with the numerical simulation. The full electrical behavior can be described using a basic drift–diffusion model with constant mobilities and direct photon-to-charge conversion. With this model we extract charge carrier mobilities in the order of 10−4cm2/Vs, a Langevin recombination prefactor of 0.08, charge injection barriers equal at both sides in the range of 0.25eV and further device parameters for a BHJ cell with PT5DPP as donor and PCBM (C70) as acceptor. The solar cell is simulated with the extracted parameters and internal distribution of electrons, holes and the electric field are visualized.

Stability and Probability 1 Convergence for Queueing Networks via Lyapunov Optimization

Lyapunov drift is a powerful tool for optimizing stochastic queueing networks subject to stability. However, the most convenient drift conditions often provide results in terms of a time average expectation, rather than a pure time average. This paper provides an extended drift‐plus‐penalty result that ensures stability with desired time averages with probability 1. The analysis uses the law of large numbers for martingale differences. This is applied to quadratic and subquadratic Lyapunov methods for minimizing the time average of a network penalty function subject to stability and to additional time average constraints. Similar to known results for time average expectations, this paper shows that pure time average penalties can be pushed arbitrarily close to optimality, with a corresponding tradeoff in average queue size. Further, in the special case of quadratic Lyapunov functions, the basic drift condition is shown to imply all major forms of queue stability.

Test procedure for drift reducing equipment.

Drift is one of the main paths of plant protection products to non-target organisms. In Germany great efforts are made to reduce drift. Therefore sprayers are tested concerning their drift reducing ability in relation to the German basic drift values which have been determined on the basis of more than 180 drift trials with conventional sprayers. A classification system with classes of at least 50 %, 75 % and 90 % drift reduction has been introduced. Sprayers which meet the requirements of the German guideline are listed in the list of drift reducing sprayers. Nearly all of the sprayers are equipped with air injection nozzles to produce larger droplets. In orchards and hops further measures like shields on fan outlets, green detectors or tunnels are necessary to achieve the respective drift classes. Newer trials show that a drift reduction of 99 % in orchards is possible.

Amplification of a Surface-Intensified Eddy Drift along a Steep Shelf in the Eastern Mediterranean Sea

Abstract The datasets of the Eddies and Gyre Path Tracking (EGYPT)/EGITTO program in the eastern Mediterranean Sea reveal a large mesoscale anticyclone traveling along the Libyan shelf. Surface drifter trajectories combined with a CTD transect accurately quantify the horizontal velocity and the vertical structure of this surface-intensified anticyclone. The observed westward drift speed is significantly higher than expected from the beta effect alone. To study the impact of a steep shelf topography on the propagation of compact surface-intensified vortices, the authors used a two-layer beta-plane model with steep continental slope and nearly zonal boundary. A perturbation theory derived by G. Sutyrin for a circular vortex in the upper layer with the lower layer at rest as a basic state is generalized for nonuniform slope in the presence of the image effect. An integral momentum balance is used to derive the drifting velocity of an upper-layer vortex with the main assumption that a stable and steady drifting solution of the two-layer system exists. The interface is described by a steady drifting circular dome at the leading order. This approach allows the problem to be reduced to the calculation of the deep-flow pattern, depending on the interface shape and topography. When the topographic slope beneath the eddy changes rapidly from a steep continental slope to a gentle continental rise, most of the deep-flow pattern is shifted offshore. The corresponding anticyclonic deep-flow feedback provides an additional along-slope propagation, which is proportional to the basic drift speed and the steepness parameter.

Experimental determination of sensitivity of piezoquartz microweighing using an electrochemical method

The sensitivity of a piezoquartz microweighing device was determined experimentally using an electrochemical method working in a real time mode. The results obtained confirmed the linearity of the dependence of the piezoquartz generator’s basic frequency drift on the mass of an applied metal for a wide measurement range.

Laboratory studies of drift waves: nonlinear mode interaction and structure formation in turbulence

Coherent drift modes and drift wave turbulence are studied in a collisionality dominated high-density helicon plasma. The drift wave instability is identified by comparison of the drift mode density fluctuation characteristics with a linear dispersion relation, which reproduces the experimentally observed bent eigenmode structures due to the radial gradients of the collisionality profile. Attention is especially paid to the parallel currents associated with the drift mode density fluctuations, which are in agreement with the basic drift wave instability mechanism. A coupling of the drift mode to the externally excited Alfvén waves is found, which results in the frequency changes of the drift mode. The parallel currents associated with radially propagating density fluctuation structures in drift wave turbulence are similar to the drift mode case, which strongly suggests that polarization of the structures is a result of the parallel electron dynamics.

Townsend coefficient, escape curve, and efficiency of runaway-electron beam formation in argon

The ionization and drift characteristics of electrons in argon are simulated by the method of multi-particle dynamics. It is shown that, in argon (as well as in other gases studied earlier), the Townsend regime of ionization sets in even in strong fields if the electrode distance is much larger than the reciprocal Townsend coefficient. The dependences of the basic ionization and drift characteristics on the reduced field intensity are obtained, and an escape curve is constructed separating the region of effective electron multiplication from the region where the electrons leave the discharge gap having no time to multiply. The formation efficiency of a runaway-electron beam is calculated. It is shown that the dependence of the electrode voltage generating a given fraction of runaway electrons on the product of the pressure by the electrode distance has a form that qualitatively agrees with the runaway curve. When the efficiency is not too high (≤20%), the runaway curves virtually coincide with isoefficiency curves.

Noncontact measurement of electrostatic fields: Verification of modeled potentials within ion mobility spectrometer drift tube designs

The heart of an ion mobility spectrometer is the drift region where ion separation occurs. While the electrostatic potentials within a drift tube design can be modeled, no method for independently validating the electrostatic field has previously been reported. Two basic drift tube designs were modeled using SIMION 7.0 to reveal the expected electrostatic fields: (1) A traditional alternating set of electrodes and insulators and (2) a truly linear drift tube. One version of the alternating electrode/insulator drift tube and two versions of linear drift tubes were then fabricated. The stacked alternating electrodes/insulators were connected through a resistor network to generate the electrostatic gradient in the drift tube. The two linear drift tube designs consisted of two types of resistive drift tubes with one tube consisting of a resistive coating within an insulating tube and the other tube composed of resistive ferrites. The electrostatic fields within each type of drift tube were then evaluated by a noncontact method using a Kelvin-Zisman type electrostatic voltmeter and probe (results for alternative measurement methods provided in supplementary material). The experimental results were then compared with the electrostatic fields predicted by SIMION. Both the modeling and experimental measurements reveal that the electrostatic fields within a stacked ion mobility spectrometer drift tube are only pseudo-linear, while the electrostatic fields within a resistive drift tube approach perfect linearity.

Pesticide interception by emergent aquatic macrophytes: Potential to mitigate spray-drift input in agricultural streams

An increasing amount of research has focused on alternate methods to mitigate pesticide exposure in agricultural surface waters. The interception of spray-drift-derived azinphos-methyl (AZP) by emergent aquatic macrophytes was investigated in a tributary of the Lourens River, South Africa. The stream was dominated (80% coverage) by three species of emergent aquatic macrophytes; Juncus capensis , Fuirena hirsuta and Pycreus sp. During an application of AZP, drift deposition was determined on the surface of the vegetation, on the surface of the exposed channel of the stream and beneath J. capensis and F. hirsuta by means of drift collectors ( n = 6). Drift deposition on the surface of the vegetation (1.5 ± 0.3 mg/m 2 ) was well predicted by 90th percentile basic drift values (1.3 mg/m 2 ), indicating that the sampling devices resulted in an accurate measurement of drift deposition. Drift deposition on the surface of the exposed channel (1.0 ± 0.3 mg/m 2 ) was lower than measured on the vegetation surface indicating a positive shielding effect by the emergent plants. Drift deposition beneath J. capensis was significantly lower ( p = 0.005) than on the vegetation surface and the exposed channel ( p = 0.048), indicating highly effective interception of AZP. A simple formula was generated to make predictions of drift deposition reductions based on different percentage macrophyte coverage. Predictions showed that 50% macrophyte coverage in combination with a 5 m buffer strip resulted in as large a reduction in drift deposition as the combination of a 10 m buffer strip with 0% macrophyte coverage. Results thus indicate that emergent aquatic vegetation may be as effective a mitigation strategy for reducing spray-drift induced pesticide input as increasing the width of the no spraying buffer zone.

Townsend coefficient and efficiency of the formation of runaway electrons in neon

Basic ionization and drift properties are simulated for neon by the method of multiparticle dynamics. This calculation revealed that, in neon—in just the same way as in other gases that were studied previously—the Townsend ionization regime is realized even in strong fields if the distance between electrodes is rather large. The dependences of basic ionization and drift properties on the reduced electric-field strength are obtained. The results agree with available experimental data. The escape curve separating the region of efficient electron multiplication from the region in which electrons leave the discharge gap without undergoing multiplication is found for neon. The efficiency of the formation of a runaway-electron beam in helium and neon is simulated.

Electrostatic vortices associated with ion-temperature-gradient driven drift modes in electron-positron-ion plasmas

A set of nonlinear equations governing the dynamics of low-frequency electrostatic waves in the presence of equilibrium density, temperature, magnetic field and electrostatic potential gradients has been derived. In the linear limit, it is shown that nonzero equilibrium ion-temperature-gradient and the presence of positrons modify the basic drift modes. On the other hand, in the nonlinear case, it is shown that under certain conditions possible stationary solutions of the same set of nonlinear equations are reduced in the form of various types of vortex patterns. The results of the present investigation should be useful to understand the wave phenomena in laboratory and astrophysical e-p-i plasmas.