scholarly journals Construção de um sensor de condutividade elétrica do solo: uma proposta multidisciplinar

2019 ◽  
Vol 40 ◽  
pp. 107
Author(s):  
Fernando Siqueira Scherer ◽  
Silvana Maldaner ◽  
Matheus Vinícius dos Santos Mello ◽  
Priscila Bernardeli Miranda ◽  
Andrei Da Cunha Lima ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Voltage Drop ◽  
Specific Resistance ◽  
Low Cost ◽  
Input Voltage ◽  
Important Variable ◽  
Simple Circuit ◽  
Conductive Plate ◽  
The Wire

The electrical conductivity of the soil is an important variable in agriculture. Their knowledge is essential in fertirrigation and can assist in soil management1. Thus, the proposal of this work is the development of a sensor to determine the electrical conductivity of the soil at low cost. To determine the electrical conductivity, the second law of Ohm (R = ρ (l / A)) is used. The equation of this law relates the electrical resistance of a conductor, with the length of the wire, area of straight section of the wire and the resistivity (or specific resistance of the material). Physically, the electrical conductivity (σ) is the inverse of the resistivity (ρ). Thus, with a microcontroller, an Arduino, a control resistor and conductive plate electrodes, a simple circuit is created to measure the electrical conductivity. The input voltage is 5v, the resistance of the control resistor is 500kohms, with this information the current in the circuit is calculated and the voltage drop in the circuit and consequently the electrical conductivity of the ground is determined.

scholarly journals Modeling the influence of thermal modification on the electrical conductivity of wood

Holzforschung ◽  
2014 ◽  
Vol 68 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Christian Brischke ◽  
Kathrin A. Sachse ◽  
Christian R. Welzbacher
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Thermal Modification ◽  
Heat Treated ◽  
Wood Temperature ◽  
Color Data

Abstract A model has been developed aiming at the description of the effect of thermal modification on the electrical conductivity of wood. The intention was to calculate the moisture content (MC) of thermally modified timber (TMT) through the parameters electrical resistance R, wood temperature T, and CIE L*a*b* color data, which are known to correlate well with the intensity of a heat treatment. Samples of Norway spruce (Picea abies Karst.) and beech (Fagus sylvatica L.) samples were thermally modified in laboratory scale at 11 different heat treatment intensities and the resistance characteristics of the samples were determined. Within the hygroscopic range, a linear relationship between the resistance characteristics and the mass loss (ML) through the heat treatment was established. Based on this, a model was developed to calculate MC from R, T, and ML. To validate this model, color values of 15 different TMTs from industrial production were determined for estimation of their ML and fed into the model. MC of the 15 arbitrarily heat-treated TMTs was calculated with an accuracy of ±3.5% within the hygroscopic range. The material-specific resistance characteristics based on experimental data led to an accuracy of ±2.5%.

scholarly journals III. The influence of stress and strain on the physical properties of matter. Part II. electrical conductivity- continued . The alteration of the electrical conductivity of cobalt, magnesium, steel, and platinum-iridium produced by longitudinal traction; Discovery of simple relations between the ‘critical points’ of metals

1884 ◽  
Vol 37 (232-234) ◽  
pp. 386-391 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Unit Area ◽  
Specific Resistance ◽  
Stress And Strain ◽  
Moderate Amount ◽  
Iron Cobalt ◽  
Temporary Decrease ◽  
Permanent Increase ◽  
Cobalt And Nickel

The effect of temporary longitudinal traction on the electrical resistance of cobalt was determined by a method similar to that already described in a former portion of this memoir, and it was found that, like nickel, this metal has its resistance decreased by moderate temporary stress, in spite of the changes of dimensions which ensue. Whether the decrease of resistance would be changed to increase, as it is with nickel, by a greater amount of stress, has not yet been ascertained, but should this be the case, the magnitude of the stress per unit area which would suffice for the purpose must be much greater with cobalt than with nickel. As with nickel, permanent extension and rolling diminish the effect of temporary longitudinal traction, so that there is a larger decrease of resistance caused by a given stress with annealed than with unannealed cobalt. Cobalt is remarkable for the extreme persistence with which the same load, when applied again, and again, continues to produce per­ manent increase of resistance, and probably increase of length, but for a moderate amount of permanent extension the increase of resistance is more than accounted for by the permanent increase of length and diminution of section which take place; so that, as with iron and nickel, the specific resistance is decreased by moderate permanent extension. The permanent decrease of specific resistance per unit for unit permanent increase of length is, for iron, cobalt, and nickel, 0.02, 1.44, and 2.37 respectively; thus the permanent decrease of specific resistance, as well as the temporary decrease of resistance, is greater with nickel than with cobalt.

scholarly journals Influence of Potential Differential Voltage on Electric Resistance of Needle Punched Non-Woven Jute Fabrics

2020 ◽  
pp. 1-6 ◽  
Keyword(s):  
Electrical Resistance ◽  
Specific Resistance ◽  
Input Voltage ◽  
Gauge Length ◽  
Electric Resistance ◽  
Jute Fabric ◽  
Differential Voltage ◽  
Jute Fabrics ◽  
Impedance Meter

In this research, the electrical resistance of needle-punched non-woven jute fabric at different input voltage was measured. Here, to determine the electrical resistance, a device named the digital impedance meter has been used. The specific resistance for the different gauge lengths of non-woven jute fabric has been observed to enhance the use of jute fabric for electrical purposes. It has been observed that the electrical resistance increased with the higher value of gauge length and decreased with the increase of input voltage.

scholarly journals Enhanced electrical conductivity and mechanical properties in thermally stable fine-grained copper wire

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Qingzhong Mao ◽  
Yusheng Zhang ◽  
Yazhou Guo ◽  
Yonghao Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Electrical Conductivity ◽  
Yield Strength ◽  
High Speed ◽  
Copper Wire ◽  
Rapid Development ◽  
Dislocation Slip ◽  
Ultrafine Grains ◽  
The Wire

AbstractThe rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive properties. Here, we demonstrate directional optimization of microstructure and overcome the strength-conductivity tradeoff in copper wire. We use rotary swaging to prepare copper wire with a fiber texture and long ultrafine grains aligned along the wire axis. The wire exhibits a high electrical conductivity of 97% of the international annealed copper standard (IACS), a yield strength of over 450 MPa, high impact and wear resistances, and thermal stability of up to 573 K for 1 h. Subsequent annealing enhances the conductivity to 103 % of IACS while maintaining a yield strength above 380 MPa. The long grains provide a channel for free electrons, while the low-angle grain boundaries between ultrafine grains block dislocation slip and crack propagation, and lower the ability for boundary migration.

scholarly journals Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1018
Author(s):  
Carola Esposito Corcione ◽  
Francesca Ferrari ◽  
Raffaella Striani ◽  
Antonio Greco
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Low Cost ◽  
Empirical Relationship ◽  
Theoretical Models ◽  
Expandable Graphite ◽  
Easy Method ◽  
Textile Materials ◽  
Fabric Materials ◽  
The Impact

In this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding pre-coating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.

scholarly journals A Low-Cost Water Depth and Electrical Conductivity Sensor for Detecting Inputs into Urban Stormwater Networks

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3056
Author(s):  
Baiqian Shi ◽  
Stephen Catsamas ◽  
Peter Kolotelo ◽  
Miao Wang ◽  
Anna Lintern ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Water Depth ◽  
Asset Management ◽  
Low Cost ◽  
Rate Of Change ◽  
Urban Drainage ◽  
Urban Stormwater ◽  
High Resolution Data ◽  
Conductivity Sensor ◽  
Level Sensor

High-resolution data collection of the urban stormwater network is crucial for future asset management and illicit discharge detection, but often too expensive as sensors and ongoing frequent maintenance works are not affordable. We developed an integrated water depth, electrical conductivity (EC), and temperature sensor that is inexpensive (USD 25), low power, and easily implemented in urban drainage networks. Our low-cost sensor reliably measures the rate-of-change of water level without any re-calibration by comparing with industry-standard instruments such as HACH and HORIBA’s probes. To overcome the observed drift of level sensors, we developed an automated re-calibration approach, which significantly improved its accuracy. For applications like monitoring stormwater drains, such an approach will make higher-resolution sensing feasible from the budget control considerations, since the regular sensor re-calibration will no longer be required. For other applications like monitoring wetlands or wastewater networks, a manual re-calibration every two weeks is required to limit the sensor’s inaccuracies to ±10 mm. Apart from only being used as a calibrator for the level sensor, the conductivity sensor in this study adequately monitored EC between 0 and 10 mS/cm with a 17% relative uncertainty, which is sufficient for stormwater monitoring, especially for real-time detection of poor stormwater quality inputs. Overall, our proposed sensor can be rapidly and densely deployed in the urban drainage network for revolutionised high-density monitoring that cannot be achieved before with high-end loggers and sensors.

scholarly journals XIX.—Magnetization and Resistance of Nickel Wire at High Temperatures. Part II.

1907 ◽  
Vol 45 (3) ◽  
pp. 547-554
Author(s):  
C. G. Knott
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Electrical Resistance ◽  
British Association ◽  
Nickel Wire ◽  
Present Communication ◽  
Association Meeting ◽  
The Subject ◽  
The Wire

The experiments which form the subject of the present communication were carried out two years ago, and supplement results already published. A brief note of some of the results was read before the Society in June 1904, and was also read before the British Association Meeting at Cambridge in August of the same year.The previous paper discussed the effect of high temperature on the relation between electrical resistance and magnetization when the wire was magnetized longitudinally, that is, in the direction in which the resistance was measured.The present results have to do with the effect of high temperature on the relation between resistance and magnetization when the magnetization was transverse to the direction along which the resistance was measured.

scholarly journals Concerning emotive phenomena. —Part III. The influence of drugs upon the electrical conductivity of the palm of the hand

1919 ◽  
Vol 91 (635) ◽  
pp. 32-40 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Healthy Subject ◽  
Electrical Resistance ◽  
Single Observation ◽  
Motor Theory ◽  
Few Data ◽  
Palm Of The Hand

I possess comparatively few data concerning the action of drugs upon “Emotivity” or, to put it more specifically, upon the electrical resistance of the palm of the hand. Except as regards atropine, with which I have made many observations to test the sudo-motor theory of the reaction, I find in my notes only one satisfactory observation upon each of the following drugs: alcohol, chloroform, morphia, which I will transcribe. Obviously, a single observation of any drug can give only a single facet of its action under the particular conditions of experiment. It will, however, be clear that the results have, in each instance, been such as might be anticipated on general principles with one notable exception, viz., atropine. Experiment 1: Alcohol . —A healthy subject, F. G., aged 30, with an initial hand conductance = 17 γ ( = 60, 000 ohms) gave emotive reactions = 37 γ to the threat of a burn (match struck) and 2 γ to an actual slight burn, immediately before and immediately after the ingestion of 50 c. c. of whisky. The conductance remained unaltered at 17 γ .

scholarly journals Temperature distribution in a permafrost-affected rock ridge from conductivity and induced polarization tomography

2020 ◽  
Author(s):  
P-A Duvillard ◽  
F Magnin ◽  
A Revil ◽  
A Legay ◽  
L Ravanel ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Temperature Distribution ◽  
Thermal State ◽  
Low Cost ◽  
Freezing Temperature ◽  
Induced Polarization ◽  
Rock Surface ◽  
European Alps ◽  
Limited Information ◽  
Polarization Tomography

Summary Knowledge of the thermal state of steep alpine rock faces is crucial to assess potential geohazards associated with the degradation of permafrost. Temperature measurements at the rock surface or in boreholes are however expensive, invasive, and provide spatially-limited information. Electrical conductivity and induced polarization tomography can detect permafrost. We test here a recently developed petrophysical model based on the use of an exponential freezing curve applied to both electrical conductivity and normalized chargeability to infer the distribution of temperature below the freezing temperature. We then apply this approach to obtain the temperature distribution from electrical conductivity and normalized chargeability field data obtained across a profile extending from the SE to NW faces of the lower Cosmiques ridge (Mont Blanc massif, Western European Alps, 3613 m a.s.l., France). The geophysical datasets were acquired both in 2016 and 2019. The results indicate that the only NW face of the rock ridge is frozen. To evaluate our results, we model the bedrock temperature across this rock ridge using CryoGRID2, a 1D MATLAB diffusive transient thermal model and surface temperature time series. The modelled temperature profile confirms the presence of permafrost in a way that is consistent with that obtained from the geophysical data. Our study offers a promising low-cost approach to monitor temperature distribution in Alpine rock walls and ridges in response to climate change.

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