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Unsaturated Soil Water Retention Characteristics, Electrical Conductivity and Compressibility of a Poorly Graded Fujian Soil Amended with Biochar
(2026-07-01)
Liu, Allen
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Garg, Ankit
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Yanning, Wang
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Kamchoom, Viroon
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Zhussupbekov, Askar
This study investigates the effect of peach shell biochar on the unsaturated soil water retention characteristics, electrical conductivity (EC), and its correlation with the compressibility of poorly graded Fujian soil, thereby addressing a critical gap in biochar research for geotechnical applications. The study aims to explore an economical approach to accessing geotechnical properties using EC. Biochar (produced at 600 °C) was mixed with sand at 0%, 5%, and 10% ratios and tested using a modified oedometer for simultaneous EC and compressibility measurements. Results reveal that 10% biochar increased EC by 354 mS/m under 200 kPa stress, a fourfold enhancement over 5% biochar (88 mS/m), attributed to conductive pathways formed by biochar particles under compression. Soil settlement decreased by 17% (0.282ΔH) and 21% (0.268ΔH) at 5% and 10% biochar, respectively, compared to bare sand (0.340ΔH). The air-entry value surged from 0.40 kPa (bare sand) to 0.71 kPa (5% biochar) and 1.41 kPa (10% biochar), enhancing moisture retention by 78% and 253%. The EC-void ratio relationship diverged markedly: bare sand showed a declining EC with reduced void ratio (0.112 Δe), while biochar-amended soils exhibited a rising EC (Δe = 0.056 for 5% and 0.036 for 10%) due to particle conduction dominating over pore-water losses. These findings offer feasible geotechnical applications: the stress-responsive EC enables real-time stability monitoring in embankments or landfill covers via non-invasive resistivity tomography, while reduced compressibility positions biochar-amended sand as a sustainable alternative for foundations in flood-prone or arid regions. Enhanced air-entry values further mitigate drought-induced cracking and erosion. The dual role of biochar, improving conductivity and mechanical stability, supports its integration into green infrastructure strategies.
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Temperature dependency of impedance, dielectric, and conductivity properties for Si-p/beta-FeSi2-n heterostructures created through facing target sputtering
(2024-08-15)
Borwornpornmetee, Nattakorn
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Sittimart, Phongsaphak
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Traiprom, Thawichai
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Paosawatyanyong, Boonchoat
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Yoshitake, Tsuyoshi
To connect thermal dependency with Si-p/beta-FeSi<inf>2</inf>-n heterostructure efficiency, this work explored the impedance characteristics accompanied by dielectric and conductivity properties under different temperatures of 160–400 K. The Nyquist impedance plots for the heterostructures showed a semicircular arc that shrank as the temperature increased. These can be equivalently interpreted as a loop of single resistance paralleled to single constant phase element representing the heterostucture which also paralleled to inductive elements representing the inductive effect, serially connected to electrode resistance. The dielectric properties implied a shift in behavior for the relaxation process since donor-acceptor deionization occurred when the temperatures reached 320 K or higher due to shorter relaxation time and higher thermal dissipation. The conductivity properties indicate that the transport mechanism at 180 K or lower involves a prolonged transitional movement before transitioning into localized hopping at higher temperatures, corresponding to faster carrier movement. The relaxation and activation energy of the heterostructure reveal drastic transition of the energy from a low temperature of 160–240 K to a higher temperature of 320–400 K, where the electrical mechanism of the heterostructures become highly dependent on the temperature likely due to the high carrier density based on unevenly high activation energy.
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Using ohmic heating to shorten the tempering time for frozen fish
(2024-03-01)
Chysirichote, Teerin
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Phumchom, Nahathai
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Chintapum, Sappayakorn
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Klinthong, Worasuang
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Ohtaguchi, Kazuhisa
Thawing is necessary to restore the freshness of fish before cooking because fish is often frozen to retain its freshness. Frequently, fish is partially thawed (or ‘tempered’) as it is easier to handle in this form than fully thawed fish. However, the conventional tempering techniques – immersion in water and still air tempering – take a long time and alter the fish's characteristics. Hence, the aim of this study was to use the heat generated inside the frozen fish, or ohmic heating, to alter the tempering process. Compared with conventional tempering operations, in this study, three voltage levels (20, 30 and 40 V/cm) were used for ohmic tempering. The fish quality and yield findings revealed that 30-V/cm ohmic heating was more appropriate, even though ohmic heating at 40 V/cm provided the shortest tempering time. The main operating expense for ohmic tempering was the power cost of USD 58.5/100 kg, whereas the major operating expense for water immersion was the cost of water supply and wastewater treatment, which was around USD 108/100 kg. By using ohmic heating instead of still air and water immersion to temper the frozen fish, not only was less time required while retaining the freshness of the fish but the cost of tempering was also reduced.
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Assessment of water quality variation for agriculture in Bang Pakong River of Thailand
(2022-09-01)
Shwe, K. K.
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Huaihongthong, S.
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Yampracha, S.
The quality of water from the river was carried out from November, 2021 to April, 2022. The water samples were collected from 13 sampling points and analyzed pH, electricity conductivity (EC), salinity, calcium (Ca2+), magnesium (Mg2+), sodium (Na+), chloride (Cl-), sulphate (SO<inf>4</inf>2-) and sodium adsorption ratio (SAR). The seawater mixing ratio was calculated using chloride concentration from the river and sea. The maximum pH value (7.56) was observed in February and the minimum value (6.53) was occurred in December among the collection months. The EC and salinity were the highest in February. The highest concentration of cation in water sample was Na+and the lowest value of cation was Ca2+. The concentration of Mg2+was higher than that of Ca2+from February to April. The sequence of major anions in water were Cl -> SO<inf>4</inf>2-. All parameters were higher in February compared to other collection months. Additionally, the highest seawater mixing ratio was observed in February (25.40%) followed by March (3.87%) and April (1.27%). The acceptable limits of irrigation water were EC (<0.7 mS cm-1), SAR (< 10) and Cl-(<10 meq L-1). The EC (13.90 mS cm-1), SAR (22.81) and Cl-(117.00 meq L-1) values were high in the river water was unsuitable for irrigation in February, which caused many problems to soil and plants. Therefore, it was concluded that the properties of water in Bang Pakong River were changed in every month depend on precipitation and freshwater flow in this region. Besides, presence of high salinity and sodicity of irrigation water other than rainwater could deteriorate the soil properties of valuable agricultural land as well as damaged the crop production. The results provided that the river water was suitable for irrigation in agricultural fields in specific month in order to increase agricultural production in this area.
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Microstructure Evolution of an Al–Fe–Ni Alloy with Zr and Sc Additions Upon Different Cooling Rates During Solidification for Improving the Mechanical and Electrical Conductivity Properties
(2021-01-01)
Chankitmunkong, Suwaree
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Eskin, Dmitry G.
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Limmaneevichitr, Chaowalit
Al–Fe–Ni eutectic alloys have high potential for being alternative aluminum alloys for various electronic and electrical applications instead of conventional low-conductivity Al casting alloys. Furthermore, the addition of Zr and Sc up to 0.3–0.6 wt% improves the hardness for high temperature applications, which is a result of the finer Al–Fe–Ni eutectic structure, and precipitation hardening of Al<inf>3</inf>Zr and/or Al<inf>3</inf>Sc nanoprecipitates. Thus, the aim of the present contribution is to analyze the microstructure features changes in an Al-1.75Fe–1.25Ni eutectic alloy upon different cooling rates during solidification. The features of Al–Fe–Ni eutectics and intermetallics were studied quantitatively, and the mechanical properties and electrical conductivity were measured.
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Effect of B doping on electrical and thermal properties of SiC bodies fabricated by spark plasma sintering
(2019-01-01)
Taki, Yukina
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Kitiwan, Mettaya
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Katsui, Hirokazu
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Goto, Takashi
B-doped SiC bodies were fabricated by spark plasma sintering at 2373 K, 50 MPa, 300 s in a vacuum and N<inf>2</inf> atmosphere. The relative density of 1 mol% B doped-SiC body sintered in a vacuum and 5 mol% B doped-SiC body sintered in N<inf>2</inf> atmosphere were 97 and 98%, respectively. The electrical conductivity of B-doped SiC bodies sintered in a vacuum with 0.5 mol% B and that with 1 mol% B sintered in N<inf>2</inf> atmosphere showed semi-insulative conduction in the range of 3-510-3 S m-1 at room temperature. The thermal conductivity of B-doped SiC body at 0.5 at% B sintered in a vacuum were 185 W m-1 K-1 while that at 1 at% B sintered in N<inf>2</inf> atmosphere were 177 W m-1 K-1 at room temperature.
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Enhancing the electrical conductivity and thermoelectric figure of merit of the p-type delafossite CuAlO2 by Ag2O addition
(2017-10-01)
Pantian, Sarayut
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Sakdanuphab, Rachsak
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Sakulkalavek, Aparporn
(CuAlO<inf>2</inf>)<inf>1-x</inf>(Ag<inf>2</inf>O)<inf>x</inf> specimens with 0 ≤ x ≤ 0.06 were prepared through the sintering of mixtures of CuO, Al<inf>2</inf>O<inf>3</inf> and Ag<inf>2</inf>O powders at 1373 K. Hall effect, Seebeck coefficient and electrical conductivity measurements were subsequently employed to assess the electrical transport properties. The electrical conductivity of the as-sintered samples was found to increase with Ag<inf>2</inf>O addition as a result of increases in the carrier density. Over the temperature range of 323–623 K, the transport properties can be attributed to thermally activated transitions from the acceptor state to the valence band. In contrast, the variable range hopping theory is applicable over the temperature range of 623–873 K. Ag<inf>2</inf>O addition evidently reduces the defect binding energy in the electronic structure of the CuAlO<inf>2</inf>. The addition of this compound also obstructs the formation of both a spinel phase and CuO, such that the oxygen off-stoichiometry value and the carrier density are increased with increasing Ag<inf>2</inf>O levels. The presence of Ag metal has the main effect on thermal conductivity below 400 K, while above 400 K increases in the phonon concentration affect the conductivity. The highest value obtained for the figure of merit was 0.0044 at 573 K, from a sample containing 0.2 at.% Ag<inf>2</inf>O.
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Low-ripple output interface circuit for electrical conductivity measurement
(2016-01-01)
Kaewpoonsuk, Anucha
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Suphramit, Suphawadee
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Rerkratn, Apinai
In this paper, an interface circuit for measuring the electrical conductivity of electrolyte solution is dcscribcd. It consists of a quadrature oscillator, a non-Inverting amplifier, a voltage-to-current converter, a peak detector, a sample-and-hold circuit, and the designed control signal generator. The proposed technique is based on the use of peak-and-hold method to detect the amplitude of sinusoidal output signal instead of the traditional method that uses the rectifier circuit connected with low-pass filter. The proposed circuit provides the obtained output in the form of DC voltage with Low ripple and fast response. Experimental results verifying the circuit performance are agreed with the theoretical values.
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Designing apparatus for highly precise measurement of electrical conductivity and seebeck coefficient from 85 k to 1200 k
(2013-10-04)
Budngam, Sopon
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Wichainchai, Aree
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Pimmongkol, Saichol
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Tipparach, Udom
We describe the development of apparatus for measuring of electrical conductivity and Seebeck coefficient with high precision from 85 K to 1,200 K. Electrical resistance was measured by means of four-point probe method as a function of temperature. The temperature below 400 K was measured by using type T thermocouple in vacuum system was used and from 400 to 1,200 was measured by using Type S was applied for temperature between 400 and 1200 Kelvin in an inert gas system. With the dimensions of the specimen, the electrical resistivity (ρT) can be obtained in the unit of microohm-centimeter (μΩ - cm) and be written in polynomial, ρ<inf>T</inf> = -0.3191 + 6.8 × 10-3T - 6.0 × 10-7 T2 + 8.0 × 10-10T3. The electrical conductivity can be obtained by taking inversion of the electrical resistivity. Seebeck coefficient (α<inf>T</inf>) can be calculated in microvolt per Kelvin as follows: α<inf>T</inf> = 1.9653 - 1.49 × 10-2T + 9.0 × 10-5T2 - 2.0 × 10-7T3 + 2.0 × 10-10T4 - 1.0 × 10-13T5 + 3.0 × 10-17T6 when T is temperature in K. The Seebeck coefficient data was compared with X-ray diffraction (XRD) and X-ray fluorescence (XRF) of the specimen. The result showed that our developrd apparatus yields the same as standard method when copper with purity greater than 99 percent was employed. © (2013) Trans Tech Publications, Switzerland.
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Effects of chloride and sulfate in various N and K fertilizers on soil chemical properties and nutrient concentrations in durian leaf and fruit
(2006-01-01)
Poovarodom, S.
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Phanchindawan, N.
Durian growers in Eastern Thailand prefer potassium sulfate (K <inf>2</inf>SO<inf>4</inf>) to potassium chloride (KCl) even though potassium chloride is twice as cheap. It is widely believed that potassium sulfate will result in better fruit quality, including flesh color. In addition, some growers believe that chloride accumulation due to KCl application will be harmful to durian trees. The purpose of this investigation is to study whether sulfate fertilizers can be effectively replaced with chloride fertilizers. The effects of N and K fertilizers containing chloride and sulfate on electrical conductivity (EC), exchangeable K, extractable S, chloride in soil, and nutrient concentrations in durian leaf and fruit from a mature orchard at Chantaburi, Thailand were examined. The topsoil, a Typic Paleudults, was a sandy clay loam (pH 5.0, EC 195 μS cm-1) with clay loam subsoil. The experiment consisted of six treatments, i.e. 1) Urea + KCl, 2) NH<inf>4</inf>Cl + KCl, 3) (NH<inf>4</inf>)<inf>2</inf>SO<inf>4</inf> + KCl, 4) Urea + K<inf>2</inf>SO <inf>4</inf>, 5) NH<inf>4</inf>Cl + K<inf>2</inf>SO<inf>4</inf>, and 6) (NH <inf>4</inf>)<inf>2</inf>SO<inf>4</inf> + K<inf>2</inf>SO<inf>4</inf>. Each treatment was repeated six times on six different trees. Nitrogen and K were applied at 1,500 g N tree-1 year-1 and 2,000 g K <inf>2</inf>O tree-1 year-1, respectively. For all treatments, the amount of exchangeable K increased for three weeks before returning to approximately its original level. All six treatments also caused the EC to increase for two to three weeks before declining. The highest EC (450 μS cm-1) was far below the unacceptable level, suggesting that sulfate fertilizers can be replaced with chloride compounds without harmfully affecting the EC of the soil. In contrast, all forms of N and K fertilizers did not significantly affect N and K concentration in durian leaves, whereas S was higher in treatments containing sulfate either with N or K. The highest leaf S concentration of 0.19% was measured in the (NH<inf>4</inf>)<inf>2</inf>SO <inf>4</inf> + K<inf>2</inf>SO<inf>4</inf> treatment. For chloride, it was found that NH<inf>4</inf>Cl, either applied with KCl or K<inf>2</inf>SO4, resulted in the highest concentration of 0.12% chloride in leaves. The lowest value of 0.02% chloride was observed in treatments without chloride application. Nonetheless, it was found that higher levels of S and Cl in the leaves did not translate into a higher S and Cl concentration in durian fruit. In conclusion, this study suggested that KCl could be used as an effective replacement for K<inf>2</inf>SO<inf>4</inf> in this soil.

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