Water Content Estimation in Soils Using Novel Planar Electromagnetic Sensor Arrays

2013 ◽  
Vol 64 (5) ◽  
Author(s):  
Mohd Amri Md Yunus ◽  
Syahrul Hisyam Mohamad ◽  
Alif Syarafi M. Nor ◽  
Muhammad Hafis Izran ◽  
Sallehuddin Ibrahim

Agriculture is one of the important sectors for food supplies. Therefore, a tool for monitoring the agro-environment is important in order to maintain the permanence of agricultural soils. This paper suggests an alternative method for the detection of water content in soils by developing a sensor array with a combination of planar meander and interdigital electromagnetic sensors. The study involved sensor array fabrication using the printed circuit board (PCB) method. The experimental setup consisted of a frequency waveform generator and a signal oscilloscope to collect and analyse the sensors’ output, with VEE Agilent software used to establish the interface. A set of experiments was conducted to determine the relationship between the sensors’ output and the soils’ parameters. The performance of the system was observed where the sensors were tested with the addition of various kinds of soil samples with different concentrations of water content. The sensitivity of the developed sensors was evaluated where the best sensor was selected. Based on the outcomes of the experiments, the Y sensor array placement has the highest sensitivity and can be used to measure the water content in the soils where the data accuracy is compared

2013 ◽  
Vol 24 ◽  
pp. 1360014
Author(s):  
MIN-SEOK KIM ◽  
HAN-WOOK SONG ◽  
YON-KYU PARK

We have developed a flexible tactile sensor array capable of sensing physical quantities, e.g. force and temperature with high-performances and high spatial resolution. The fabricated tactile sensor consists of 8 × 8 force measuring array with 1 mm spacing and a thin metal (copper) temperature sensor. The flexible force sensing array consists of sub-millimetre-size bar-shaped semi-conductor strain gage array attached to a thin and flexible printed circuit board covered by stretchable elastomeric material on both sides. This design incorporates benefits of both materials; the semi-conductor's high performance and the polymer's mechanical flexibility and robustness, while overcoming their drawbacks of those two materials. Special fabrication processes, so called “dry-transfer technique” have been used to fabricate the tactile sensor along with standard micro-fabrication processes.


2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Andrew K. Evers ◽  
Tyler A. Demers ◽  
Andrew M. Gordon ◽  
Naresh V. Thevathasan

Earthworms may have an influence on the production ofN2O, a greenhouse gas, as a result of the ideal environment contained in their gut and casts for denitrifier bacteria. The objective of this study was to determine the relationship between earthworm (Lumbricus terrestrisL.) population density, soil water content andN2Oemissions in a controlled greenhouse experiment based on population densities (90 to 270 individualsm−2) found at the Guelph Agroforestry Research Station (GARS) from 1997 to 1998. An experiment conducted at considerably higher than normal densities of earthworms revealed a significant relationship between earthworm density, soil water content andN2Oemissions, with mean emissions increasing to 43.5 gha−1day−1at 30 earthworms 0.0333 m−2at 35% soil water content. However, a second experiment, based on the density of earthworms at GARS, found no significant difference inN2Oemissions (5.49 to 6.99 gha−1day−1) aa a result of density and 31% soil water content.


1984 ◽  
Vol 11 (2) ◽  
pp. 165-172
Author(s):  
A. Kerkhoff

Involving, as it does, DIN and Reversed DIN board connectors, compliant press-fit pins, round cable, flat cable, and coaxial-connectors, the Berg Backpanel System has, over the past two years, gained a recognized position in the European and US markets.Development and expansion of the system in depth, and in breadth, is still ongoing. One of the major subjects is press-fit: preloaded press-fit connectors and studies focused on the relationship between printed circuit board properties vs. compliant press-fit pin design.This paper presents results of these developments and discusses design options.


2014 ◽  
Vol 609-610 ◽  
pp. 593-599
Author(s):  
He Zhang ◽  
Xiao Wei Liu ◽  
Li Tian ◽  
Xiao Wei Han ◽  
Shang Yu Liu

In this paper, we fabricated a novel multilayer microfluidic device with vertical embedded electrodes. The device was composed of printed circuit board (PCB) substrate with vertical embedded electrodes, the polyimide insulating layer and the polymethyl methacrylate (PMMA) with micro structures. The vertical electrodes were made by metal wire and integrated on the PCB substrate, they can be replaced when fail or broken. In addition, we investigated the relationship between electrodes height and the electro-osmotic flow by using numerical simulation. The results show that, with the increase electrodes height inside the microchannel, the speed of electro-osmotic flow increased and concentration field distribution improved significantly.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1058 ◽  
Author(s):  
R. Mansour ◽  
S. Rioual ◽  
B. Lescop ◽  
P. Talbot ◽  
M. Abboud ◽  
...  

In this study, a sensor based on the development of a planar antenna immersed in sediments dedicated to water content monitoring in this type of material is proposed and experimentally validated. It is produced by a conventional Printed Circuit Board (PCB) manufacturing process on a double-sided metalized FR4 substrate. The sensitivity of the sensor is ensured by the variation of the real part of the complex dielectric permittivity of sediments with water content at around 1 GHz. As shown, in this frequency range, electrode polarization and Maxwell–Wagner polarization effects become negligible, leading to only a bulk water polarization sensitivity. The sensor operates in the reflection mode by monitoring the variation of the resonant frequency as a function of the sediment density through the S11 reflection measurements. An experimental sensitivity of 820   MHz . g − 1 . cm 3 was achieved. Despite the simplification of data interpretation at the considered frequency, the influence of ionic species such as NaCl in sediments on the real part of the relative complex dielectric permittivity is highlighted. This demonstrates the importance of considering a second parameter such as the S11 level at low frequency or the electrical conductivity to extract the density from the frequency measurements.


Author(s):  
M. ZAGNONI ◽  
A. GOLFARELLI ◽  
P. PROLI ◽  
S. CALLEGARI ◽  
A. TALAMELLI ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Flávio Morais ◽  
Pedro Carvalhaes-Dias ◽  
Luís Duarte ◽  
Eduardo Costa ◽  
Alexandre Ferreira ◽  
...  

We present a capacitive smart sensor based on printed circuit board (PCB) technology to measure the amount of water content in a paper pulp at the wet end of a paper machine. The developed sensor incorporates in the same PCB the signal processing circuits. It is a handheld portable device, and its output is sent to the reading equipment using a Bluetooth wireless connection, providing to the sensor’s operator ease of mobility around the wet end of a paper machine. The prototype was tested in a laboratory, using a wire mesh to emulate the end of a paper machine, and we were able to measure and easily detect when it reaches the water content in the range of 90% to 92%, as required in the paper fabrication process. Standard deviation of the capacitance measurements at various moisture levels is four orders of magnitude smaller than the mean. The smart sensor was tested in the 20°C to 40°C temperature range, in a paper pulp with a gravimetric water content of 91%. Since the variation of capacitance with temperature is practically linear, we propose a simple linear compensation equation to correct the observed sensitivity with the temperature. To keep the signal processing circuits small, low cost, simple, and robust, a novel direct interface sensor to microcontroller circuit technique was used to make the capacitive measurement, allowing for measuring small capacitance deviations without high-frequency oscillators. It was shown that it is possible to integrate the signal processing circuits in the top layer of the PCB interdigitated sensor without adding noise or degrading the performance of the capacitive sensor.


Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 348
Author(s):  
Matko Martinic ◽  
Tomislav Markovic ◽  
Adrijan Baric ◽  
Bart Nauwelaers

In this study, complementary split-ring resonator (CSRR) metamaterial structures are proposed for label-free dielectric spectroscopy of liquids in microplates. This novel combination of an array of sensors and microplates is readily scalable and thus offers a great potential for non-invasive, rapid, and label-free dielectric spectroscopy of liquids in large microplate arrays. The proposed array of sensors on a printed circuit board consists of a microstrip line coupled to four CSRRs in cascade with resonant frequencies ranging from 7 to 10 GHz, spaced around 1 GHz. The microwells were manufactured and bonded to the CSRR using polydimethylsiloxane, whose resonant frequency is dependent on a complex relative permittivity of the liquid loaded in the microwell. The individual microstrip lines with CSRRs were interconnected to the measurement equipment using two electronically controllable microwave switches, which enables microwave measurements of the 4 × 4 CSRR array using only a two-port measurement system. The 4 × 4 microwell sensor arrays were calibrated and evaluated using water-ethanol mixtures with different ethanol concentrations. The proposed measurement setup offers comparable results to ones obtained using a dielectric probe, confirming the potential of the planar sensor array for large-scale microplate experiments.


Author(s):  
Takahiro Omori ◽  
Kenji Hirohata ◽  
Tomoko Monda ◽  
Minoru Mukai

There is high demand for fatigue life prediction of solder joints in electronic packages such as ball grid arrays (BGAs). A key component of fatigue life prediction technology is a canary device, which warns of the impending risk of failure through loss of function before other important parts become severely impaired. In a BGA package, thermal fatigue of solder joints normally starts from the solder joints at the outermost part of the package. This can be taken advantage of by using the outermost solder joints as canary devices for detecting the degree of cumulative mechanical fatigue damage. To accurately estimate the lifetimes of other functional solder joints, it is essential to understand the relationship between the fatigue lives of canary joints and other functional joints. Damage path simulation is therefore proposed for predicting the crack propagation in solder joints on electronic packages through numerical simulation. During the process of designing the layout of canary joints and other joints, it is very useful to know not only the relationship between the fatigue lives of the canary and other joints, but also the path of crack propagation through all joints. This paper presents a method for estimating the relationship between the fatigue lives of canary joints and other joints by using damage path simulation. Some BGA packages mounted on a printed circuit board are modeled to demonstrate the process of estimating the lifetime of each joint under thermal cycle loading. A large-scale finite element model is used to accurately represent the geometrical properties of the printed circuit board and package. Both crack initiation and crack propagation processes can be simultaneously evaluated by modeling all of the solder joints on each package. The results show that damage path simulation and large-scale modeling are useful for determining the layout of canary joints in electronic packages.


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