Use Of Electrical Conductivity Research Articles

Roadmap for Power Generation of Industrial Hot Extruded Bi2Te3-Based Thermoelectric Device in Real-World Heat Sources.

Recovering waste heat through thermoelectric (TE) technology is critical for enhancing energy efficiency. However, commercial devices often require n- and p-type thermoelectric units to have similar cross-sectional areas and conductivities, complicating optimization of their figure of merit (ZT). Moreover, real-world heat sources are not constant temperature sources, and only heat flux can be measured. Given these constraints, selecting appropriate parameters for TE devices to maximize their output power for specific heat sources is of significant scientific and practical importance. In this work, we studied a series of n- and p-type Bi2Te3-based TE materials, prepared using commercial hot extrusion techniques, with average conductivities of approximately 650 S cm-1, 820 S cm-1, 1050 S cm-1, and 1300 S cm-1 over the temperature range of 50-250 °C. These materials were assembled into four different thermoelectric devices (HE1, HE2, HE3, and HE4). Finite element simulations for devices HE1, HE2, HE3, and HE4 (TE leg: 1.4 mm × 1.4 mm × 1.6 mm, device area: 40 mm × 40 mm) showed maximum power densities of 3953.5 W m-2 and 1300.8 W m-2 at 67,000 W m-2 and 33,500 W m-2 heat fluxes, respectively. The fabricated devices achieved maximum power densities of 2907.1, 3014.0, 2910.9, and 2525.4 W m-2 at 67,000 W m-2 heat flux, with discrepancies attributed to interface thermal resistance. Based on these findings, we have plotted output performance roadmaps for TE devices with different average electrical conductivities under various heat flux densities (67,000 W m-2 and 33,500 W m-2) as functions of external load and TE leg height. These roadmaps enable rapid design of TE devices tailored to specific external heat source conditions and cost requirements, thereby maximizing waste heat recovery. This study's use of electrical conductivity as a performance indicator for final device output power density offers direct guidance for practical waste heat recovery applications.

The use of electrical conductivity to develop temporally precise breakthrough curves in tracer injection experiments

Tracer injection is a common technique in the studies of chemical transport in streams and channels. One of its limitations is the requirement of frequent sampling for representative tracer breakthrough data. Frequent collection and analysis of water samples are normally expensive and time-consuming. The measurement of electrical conductivity (EC) is a potential alternative to sample collection and analyses, because of its ease of data acquisition. But whether the EC value can characterize the injected solute concentration requires further evaluation. This article assesses the ability of EC to predict solute concentrations in tracer injections. Two injection studies were conducted in two separate flumes: an instantaneous injection of phosphorus (P) and bromide (Br) in a 20-m flume and a constant injection of P in a 10-m flume. Water samples were collected intensively at multiple locations and EC was automatically and continuously recorded. Using a linear model, a solute breakthrough was calculated based on recorded EC and compared to the measured solute concentrations.The results showed that the EC-solute relationship can reduce the number of water samples needed for an accurate solute breakthrough. A small sample of paired recorded EC and solute concentrations can be used to build a model for each tracer study. By collecting at least 9 water samples at specific times, i.e., at shoulder, peak, and tail of a breakthrough curve, a simple regression model can efficiently predict P concentrations. The correlation is 80% or greater between predicted and observed concentrations, confirming that EC successfully traced P presence in water and can be used to facilitate tracer injection studies.

Teste de condutividade elétrica na avaliação do potencial fisiológico de sementes de grão de bico

The vigor tests were developed to compensate for deficiencies in the germination test. This study aimed to evaluate the use of electrical conductivity in the physiological potential of chickpeas seeds. Four seed lots of cultivar ‘BRS Aleppo, were tested for germination, first count germination, seedling emergence, speed of emergence and accelerated aging. For the electrical conductivity were studied variations in the volume of water (50 and 75mL), temperature (25 and 30oC), number of seeds (25 and 50) and imbibed (1, 2, 4, 6, 12, 18 and 24 hours). The electrical conductivity test was efficient for the chickpeas seeds, and the soaking time can be reduced to four hours, but using 50 seeds failed to differentiate between batches. The volume of 25mL and 30°C was the most favorable condition for the consistent ordering of the lots on the force. The best conditions for the electrical conductivity in chickpeas seed are the use of 25 seeds in 50mL of water for four hours at 30oC.

Multi-step water quality forecasting using a boosting ensemble multi-wavelet extreme learning machine model

The use of electrical conductivity (EC) as a water quality indicator is useful for estimating the mineralization and salinity of water. The objectives of this study were to explore, for the first time, extreme learning machine (ELM) and wavelet-extreme learning machine hybrid (WA-ELM) models to forecast multi-step-ahead EC and to employ an integrated method to combine the advantages of WA-ELM models, which utilized the boosting ensemble method. For comparative purposes, an adaptive neuro-fuzzy inference system (ANFIS) model, and a WA-ANFIS model, were also developed. The study area was the Aji-Chay River at the Akhula hydrometric station in Northwestern Iran. A total of 315 monthly EC (µS/cm) datasets (1984–2011) were used, in which the first 284 datasets (90% of total datasets) were considered for training and the remaining 31 (10% of total datasets) were used for model testing. Autocorrelation function (ACF) and partial autocorrelation function (PACF) demonstrated that the 6-month lags were potential input time lags. The results illustrated that the single ELM and ANFIS models were unable to forecast the multi-step-ahead EC in terms of root mean square error (RMSE), coefficient of determination (R2) and Nash–Sutcliffe model efficiency coefficient (NSC). To develop the hybrid WA-ELM and WA-ANFIS models, the original time series of lags as inputs, and time series of 1, 2 and 3 month-step-ahead EC values as outputs, were decomposed into several sub-time series using different maximal overlap discrete wavelet transform (MODWT) functions, namely Daubechies, Symlet, Haar and Coiflet of different orders at level three. These sub-time series were then used in the ELM and ANFIS models as an input dataset to forecast the multi-step-ahead EC. The results indicated that single WA-ELM and WA-ANFIS models performed better than any ELM and ANFIS models. Also, WA-ELM models outperformed WA-ANFIS models. To develop the boosting multi-WA-ELM and multi-WA-ANFIS ensemble models, a least squares boosting (LSBoost) algorithm was used. The results showed that boosting multi-WA-ELM and multi-WA-ANFIS ensemble models outperformed the individual WA-ELM and WA-ANFIS models.

Solubilization of Benzothiazole (BNZ) by micellar media of Sodium dodecyl sulphate and Cetyl trimethylammonium bromide

In the present study, we have provided an insight into the solubilization of bioactive compound Benzothiazole (BNZ) by the micellar media of an anionic surfactant, Sodium dodecyl sulphate and a cationic surfactant, cetyl trimethylammonium bromide. The detailed investigation of this phenomenon involves the use of electrical conductivity and UV–Visible spectroscopic techniques in sub-micellar and micellar concentration ranges. Furthermore, the critical micelle concentration (CMC) of the two surfactants and their respective thermodynamic properties in the presence of BNZ were determined by conductivity method, where the results suggest that the presence of BNZ increases the CMC of both surfactants. The studies from absorption spectroscopy suggest that, initially the molecules of BNZ get attached with monomeric molecules of surfactant in premicellar region, while in post-micellar region they are accommodated within the micelle.

Evaluation of wavelet performance via an ANN-based electrical conductivity prediction model.

The prediction of water quality parameters plays an important role in water resources and environmental systems. The use of electrical conductivity (EC) as a water quality indicator is one of the important parameters for estimating the amount of mineralization. This study describes the application of artificial neural network (ANN) and wavelet-neural network hybrid (WANN) models to predict the monthly EC of the Asi River at the Demirköprü gauging station, Turkey. In the proposed hybrid WANN model, the discrete wavelet transform (DWT) was linked to the ANN model for EC prediction using a feed-forward back propagation (FFBP) training algorithm. For this purpose, the original time series of monthly EC and discharge (Q) values were decomposed to several sub-time series by DWT, and these sub-time series were then presented to the ANN model as an input dataset to predict the monthly EC. Comparing the values predicted by the models indicated that the performance of the proposed WANN model was better than the conventional ANN model. The correlation of determination (R (2)) were 0.949 and 0.381 for the WANN and ANN models, respectively. The results indicate that the peak EC values predicted by the WANN model are closer to the observed values, and this model simulates the hysteresis phenomena at an acceptable level as well.

Estimativa de valores granulométricos do solo em locais não amostrados utilizando-se cokrigagem

Using the multivariate technique of kriging known as cokriging, it possible to estimate values of variables high cost of aquisition using variable of the low cost and fast acquisition, provided that both exhibit high spatial correlation. The objective of this study was to evaluate the use of electrical conductivity of 1:5 extract (ECe 1: 5) as a covariate in an analysis by cokriging to estimate the values of granulometric components of an Oxisol. In an area of 90 ha, soil samples were collected at 181 georeferenced points, at depth of 0 to 0.20 m. The samples were sent to the laboratory for characterization of soil particle size (coarse sand, fine sand, silt and clay) and measurement of ECe (1:5). Using the cokriging, we attempted to estimate the values of the variables soil texture using the ECe (1:5) as a covariate. Using the technique of cokriging, the best estimates of values for unsampled locations were obtained for the variables silt and clay, because they showed greater spatial correlation with the electrical conductivity of saturation extract (1:5).

Tracing recharge to aquifers beneath an Asian megacity with Cl/Br and stable isotopes: the example of Dhaka, Bangladesh

Dhaka, the capital of Bangladesh, is home to a population of 15 million people, whose water supply is 85% drawn from groundwater in aquifers that underlie the city. Values of Cl/Br >500 are common in groundwater beneath western Dhaka in areas <3 km from the river, and in rivers and sewers around and within the city. The study shows that groundwater beneath western Dhaka is strongly influenced by infiltration of effluent from leaking sewers and unsewered sanitation, and by river-bank infiltration from the Turag-Buriganga river system which bounds the western limit of the city. River-bank infiltration from other rivers around Dhaka is minor. Values of Cl/Br and Cl concentrations reveal that 23 % of wells sampled in Dhaka are influenced by saline connate water in amounts up to 1%. This residual natural salinity compromises the use of electrical conductivity of groundwater as a method for defining pathways of recharge by contaminated surface waters. Concentrations of As, B, Ba, Cd, Cu, F, Ni, NO3, Pb, Sb, Se and U in groundwater samples are less than WHO health-based guideline values for drinking water.

Use of Electrical Conductivity to Assess Irrigation Impacts on Grapevine Winter Hardiness

A simple method involving measurement of electrical conductivity of grapevine cane tissue was evaluated. ‘Sovereign Coronation’ vines on two sites were subjected to five irrigation treatments based upon reference evapotranspiration (ET0) and various crop coefficients (Kc): non-irrigated control; 100% ET0 × Kc = 0.75; 150% ET0 × Kc = 0.75 (ET0 × 1.12); 100% ET0 × Kc = 0.2 to 0.8; 150% ET0 × Kc = 0.2 to 0.8. ‘Chardonnay’ vines were likewise subjected to several irrigation treatments: non-irrigated control, early season deficit (irrigation until berry set), midseason deficit (irrigation until lag phase of berry growth), late season deficit (irrigation until veraison), and full season irrigation (irrigation until harvest). Cane samples were collected from December to March inclusive, and cane segments were subjected to multiple temperature treatments (−24, −26, −28, −30, −32°C) in addition to a non-treated control. Treated cane segments were thinly sliced and incubated in distilled water (t1) at room temperature and at 100°C (t2), after which the electrical conductivity (EC) was read. Two indices calculated from both EC values (ItA, ItB) were responsive to irrigation. However, there was little relationship between either ItA and ItB versus irrigation in ‘Sovereign Coronation’, likely because it is a very winter-hardy cultivar. Nonetheless, there was a relationship between both ItA and ItB versus irrigation in ‘Chardonnay’, whereby treatments to which high irrigation volumes were applied also had high ItA and ItB values, suggesting higher potential winter damage. In summary, the technique described herein is relatively inexpensive and not time-consuming and, therefore, may constitute a rapid method for assessment of grapevine winter injury.

Use of Electrical Conductivity as a Tool for Determining Damage Index of Some Mango Cultivars

Four Mango (Mangifera indicaL.) cultivars: �Ewais �, �Sidik �, �FajrikalanandZebdawere investigated to study the electrical conductivity as a tool for determining damage index of mango cultivars and theirrelationship with the index of injury (Id), the Relative Water Content (RWC), Soluble Solid Content (SSC) and total phenols. �Ewaishad the highest cold tolerance whereasFajrikalanhad the lowest cold tolerance. EC and Id values were highest at-4∞C awas a direct proportional among: cold injury, exposure time and the decreasing of temperature. Cold temperature increased the accumulation of SSC with time. Total phenols ofEwaisandFajrikalanwere lower than inZebdaandSidik �. The relationship between the RWC and the Id was not clear from this experiment.

Solubility of non-aromatic hexafluorophosphate-based salts and ionic liquids in water determined by electrical conductivity

The knowledge of the salts solubility in water is of major interest for process design and optimization and for environmental monitoring. The determination of the water solubility of non-aromatic salts or ionic liquids requires the use of specific and expensive analytical equipment. In this work the use of electrical conductivity for the quantification of the solubility of sparingly soluble salts in water is proposed. Novel data for the water solubility of 1-methyl-1-propylpyrrolidinium hexafluorophosphate, 1-methyl-1-propylpiperidinium hexafluorophosphate, tetrabutylammonium hexafluorophosphate, and tetrabutylphosphonium hexafluorophosphate, in the temperature range from 288.15 to 318.15K, are reported. Using the gathered results, along with literature data, a correlation between the aqueous solubility of [PF6]-based salts with their molar volume is proposed. The COSMO-RS predictive model was also used to estimate the solid–liquid equilibrium of the investigated systems. Since all the compounds are solid at room temperature, they were further characterized by differential scanning calorimetry, and the temperatures of solid–solid and solid–liquid phase transitions, as well as the respective enthalpies of phase transition, are presented.

Teste de condutividade elétrica na avaliação do potencial fisiológico de sementes de berinjela

A qualidade fisiológica é um dos principais objetos de estudos envolvendo sementes, pois estas podem sofrer uma série de mudanças degenerativas de diversas naturezas que culminam com a redução de seu vigor. Para suprir as deficiências do teste de germinação na caracterização de lotes, foram desenvolvidos testes de vigor, que estão muito bem caracterizados para as grandes culturas, mas recém aplicados para as sementes de olerícolas. Sendo assim, o presente trabalho teve como objetivo avaliar a utilização do teste de condutividade elétrica na avaliação do potencial fisiológico de sementes de berinjela. Quatro lotes de sementes de berinjela, cultivar 'Preta Comprida', foram submetidos a testes de germinação e vigor (primeira contagem da germinação, emergência das plântulas, índice de velocidade de emergência e envelhecimento acelerado). Para o teste de condutividade elétrica, foram estudadas variações no volume de água (50 e 75mL), temperatura (25 e 30°C), número de sementes (25 e 50) e tempo de embebição (1, 2, 4, 6, 12, 18 e 24 horas). O teste de condutividade elétrica foi eficiente para a avaliação do vigor de sementes de berinjela, com o tempo de embebição podendo ser reduzido para quatro horas, porém a utilização de 50 sementes não permitiu diferenciar os lotes. O volume de 25mL em temperatura de 30°C foi a condição mais favorável para a ordenação consistente dos lotes quanto ao vigor, de forma que a condição mais adequada para o teste de condutividade elétrica em sementes de berinjela é a utilização de 25 sementes em 50mL de água por quatro horas a 30°C.

Online estimation of VFA, alkalinity and bicarbonate concentrations by electrical conductivity measurement during anaerobic fermentation

This paper describes the use of electrical conductivity for measurement of volatile fatty acids (VFA), alkalinity and bicarbonate concentrations, during the anaerobic fermentation process. Two anaerobic continuous processes were studied: the first was a laboratory reactor for hydrogen production from molasses and the second was a pilot process for anaerobic digestion (AD) of vinasses producing methane. In the hydrogen production process, the total VFA concentration, but not bicarbonate concentration, was well estimated from the on-line electrical conductivity measurements with a simple linear regression model. In the methane production process, the bicarbonate concentration and the VFA concentration were well estimated from the simultaneous on-line measurements of pH and electrical conductivity by means of non-linear regression with neural network models. Moreover, the total alkalinity concentration was well estimated from electrical conductivity measurements with a simple linear regression model. This demonstrates the use of electrical conductivity for monitoring the AD processes.

Electrical conductivity as an indicator of iron reduction rates in abiotic and biotic systems

Although changes in bulk electrical conductivity (σb) in aquifers have been attributed to microbial activity, σb has never been used to infer biogeochemical reaction rates quantitatively. To explore the use of electrical conductivity to measure reaction rates, we conducted iron oxide reduction experiments of increasing biological complexity. To quantify reaction rates, we propose composite reactions that incorporate the stoichiometry of five different types of reactions: redox, acid‐base, sorption, dissolution/precipitation, and biosynthesis. In batch experiments and the early stages of a column experiment, such reaction stoichiometries inferred from a few chemical measurements allowed quantification of the Fe oxide reduction rate based on changes in electrical conductivity. The relationship between electrical conductivity and fluid chemistry did not hold during the latter stages of the column experiment when σb increased while fluid chemistry remained constant. Growth of an electrically conductive biofilm could possibly explain this late stage σb increase. The measured σb increase is consistent with a model proposed by analogy from percolation theory that attributes the increased conductivity to growth of biofilms with conductivity of ∼5.5 S m−1 in at least 3% of the column pore space. This work demonstrates that measurements of σb and flow rate, combined with a few direct chemical measurements, can be used to quantify biogeochemical reaction rates in controlled laboratory situations and may be able to detect the presence of biofilms. This approach may help in designing future field experiments to interpret biogeochemical reactivity from conductivity measurements.

Use of electrical conductivity to analyze depositional environments: Example of a Holocene delta sequence on the Nobi Plain, central Japan

The usefulness of electrical conductivity (EC) of stirred Holocene deltaic sediments from three cores from the Nobi Plain, Japan, was assessed as a proxy for marine transgression and regression. Lack of correlation of EC with mud content for the sediments with >20% mud suggested that permeability was a negligible factor. Marine deposits showed high EC (>0.9 mS/cm), terrestrial deposits low EC (<0.4 mS/cm), and brackish deposits intermediate. Because it was positively correlated with the percentage of marine diatom species, EC in inner-bay deposits primarily reflected salinity. In the YM core (the youngest of the three cores), EC of the inner-bay deposits was weakly positively correlated with clay content, which controls pore water content. EC of inner-bay clayey deposits was generally higher in YM than in KZN, suggesting that the lower EC in older clayey sediments results from compaction. These findings suggest that the EC values of fine sediments initially record salinity but may decrease gradually over time under the influence of compaction. Thus, to reconstruct the original salinity, the effects of compaction and of grain size distribution—and especially clay content—should be evaluated.

Electrical conductivity based characterization of plain and coarse glass powder modified cement pastes

This paper describes the use of electrical conductivity to characterize plain and coarse glass powder modified cement pastes. It is observed that the glass powder addition facilitates improved hydration of the cement grains. For the proportions investigated in this study, and the particle size of glass powder, this advantage is negated by the reduced amount of hydration products, i.e., the dilution effect. The variation of electrical conductivity and its derivative with time can be related to the various phases in the microstructural development of the paste. It is observed from the time derivative of conductivity plots that the addition of glass powder results only in minor changes in the setting time of the pastes. Higher the glass powder content, higher the normalized conductivity (ratio of conductivity at a certain glass powder content to that of plain paste) at very early times, and then it falls to a value closer to or less than 1.0 at later times. A parallel model is used to represent effective conductivity as a function of the pore solution conductivity, porosity, and pore connectivity factor. The pore solution conductivity increases with increase in glass powder content. The porosity of the pastes reduces with increase in glass powder content at early ages and increases at later ages. A reduced pore connectivity factor is observed for pastes with higher glass powder content at later times. However, this does not imply increased volume of hydration products as is commonly interpreted for normal pastes, but the electrical conduction pathways are made more tortuous by the relatively large volume of un-reacted filler material in the pore structure.

Limitations in the use of electrical conductivity to monitor the behaviour of soil solution

Solutions of KBr and K2SO4 of various concentrations were separately displaced by deionised water through 2 contrasting saturated materials, inert solid particles (glass ballotini), and a reactive but non-swelling aggregated clay mineral (sepiolite) over a wide range of flow rates. The concentration of the individual ions in the effluent was analysed (Br– and K+ with ion-specific electrodes, SO42+ by ion chromatography) and that of bulk solution was measured by electrical conductivity (EC). For each displacement, the individual breakthrough curves (BTCs) for the anion, the cation, and the bulk solution were optimised by CXTFIT 2.0. In ballotini, the BTCs of the anion, cation, and solution were always congruent, the retardation factors did not differ significantly from unity, and the coefficients of hydrodynamic dispersion were identical. For sepiolite, the ions were separated; the bulk solution eluted faster than the cation, slower than the anions. Retardation factors were always less than unity for the anions, greater than unity for the cation, and close to but less than unity for the bulk solution, and became more extreme as the concentration of solute decreased. Dispersion coefficients were, however, unaffected by type of solute, concentration range, or particular ion/EC. The separation of ions means that the composition as well as the concentration of a solution changes continuously during flow through a reactive soil. Estimates of solution concentration from measurements of EC may thus fail to characterise adequately the movement of the individual components of the solution in such materials. This has implications for the interpretation of any leachate monitoring in reactive soils by methods based on the measurement of EC, such as time-domain reflectometry.

Demarcating Management Zones for Site‐Specific Farming Using Electromagnetic Induction and Yield Maps in Eastern Oregon

Traditional farming practices in eastern Oregon ignore the inherent spatial variability (topography, soils) resulting in inefficient farming and lower net returns. Site-specific farming (SSF), or farming based on requirements of specific areas in a field, has the potential to improve input use efficiency and farm profits. To implement SSF, however, management zones should be demarcated preferably based on factors that most affect yield. The most common method for demarcating management zones is through intensive grid sampling that can be very expensive. The objective of this study was to find cheaper and quicker ways to demarcate management zones in a field in eastern Oregon. This study evaluated the use of electrical conductivity (EC) and yield maps in demarcating management zones. A 28-acre field was characterized for depth and nutrients at a 100-ft grid. Wheat was uniformly seeded throughout the field and harvested at each grid location. Results indicated that the spatial variability of wheat yield was influenced by soil depth. EC data were correlated with both depth and grain yield and can therefore be used to demarcate management zones quicker and cheaper than grid sampling in this field. Information from yield maps was also useful in demarcating management zones for SSF.

Role of curing temperature in progress of lime-soil reactions

An expansive black cotton soil was used to assess if ambient temperature influences the progress of lime-soil reactions. Lime-soil mixes containing lime additions above the Lime Modification Optimum (or Initial Consumption of Lime value) of the expansive black cotton soil was cured for periods ranging from 1 hour to 400 days at $25^0C$. The curing temperature of $25^0C$ is representative of mean temperatures occurring in semi-arid regions of Karnataka, India. The in situ progress of lime treatment was monitored by the use of electrical conductivity and pH measurements. The trend of decrease in conductivity and pH of the 4 and 7 lime-soil mixes suggested that pozzolanic activity commenced after 1 day of curing at $25^0C$. Comparatively, an earlier study by other researchers had reported that pozzolanic activity does not commence before 7 days of curing at $11.5^0C$ for lime additions above the Lime Modification Optimum value of swelling clay. Combining the results of studies at $25^0C$ and $11.5^0C$, it appears that higher ambient temperatures do accelerate the progress of lime-soil reactions.

Relações entre germinação de sementes de espécies de plantas daninhas e uso da condutividade elétrica

Experimentos foram conduzidos em laboratório com o objetivo de determinar relações entre germinação de sementes de plantas daninhas e condutividade elétrica (CE). Foram usadas sementes de amendoim-bravo (Euphorbia heterophylla), carrapicho-de-carneiro (Acanthospermum hispidum), corda-de-viola (Ipomoea grandifolia), guanxuma (Sida rhombifolia), picão-preto (Bidens pilosa) e trapoeraba (Commelina benghalensis) recentemente colhidas. As sementes foram embebidas em água por períodos de 6 até 48 horas, na temperatura de 20 ºC, determinando-se a CE das sementes e os níveis de absorção de água. Depois disso, as sementes foram colocadas para germinar. Os maiores níveis de germinação, para sementes embebidas em água por 24 horas, foram obtidos para picão-preto (88%), amendoim-bravo (31%) e guanxuma (30%); e os menores, para corda-de-viola (5%), carrapicho-de-carneiro (4%) e trapoeraba (3%). As sementes das plantas daninhas avaliadas tendem a germinar totalmente com períodos de embebição a partir de seis horas, ao passo que a sua absorção tende a aumentar e a CE das sementes, a não acompanhar os níveis de absorção ao final de maiores períodos. O uso da condutividade elétrica merece maiores estudos, uma vez que pode contribuir para uma eficiente e mais rápida avaliação da dinâmica de bancos de sementes de plantas daninhas em lavouras.