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Ultrasonic dispersion is a powerful method of dispersing soil aggregates. Several procedures are described in the literature, which use absorbed ultrasonic energy as the main parameter for correlation with the process of soil dispersion. In the present work it is shown, that the dynamic of soil dispersion additionally depends on the magnitude of ul...
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... this work ultrasonic equipment (Bandelin Sonoplus HD 2200) was used as shown in principle in Fig. 1. A pie- zoelectric ultrasonic transducer transforms a sinusoidal electrical voltage into mechanical longitudinal resonance vibration, where the resonance frequency of the equipment is 20 kHz. The equipment is mounted using a booster horn, which serves additionally to increase the vibration am- plitude. The ultrasonic probe is inserted ...
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... where ε 0 represents strain mean, F i is strain amplitude and t 0 represents the manufacturing-built time of fused filament fabrication anisotropic thin plates (s), ω is the angular velocity (rad/s), and α is the initial phase equal to zero, according to Mayer (2001) the strain amplitude F i can be rewritten as: ...
Fused Filament Fabrication (FFF), is one of the most widely used additive manufacturing technologies today, which has been used for a variety of applications. Due to the layer-by-layer manufacturing process, FFF parts are inferior to those fabricated by traditional methods in terms of tensile properties, which is one of the most significant defects that hinder the development of this technique. In this study, a vibration was utilized during the FFF process by piezoelectric ceramics electric plates to improve the mechanical properties of the built parts and surface quality of PLA FFF parts. Subsequently, an investigation of the tensile and the surface quality of PLA FFF specimens built-in X and Z-direction fabricated individually without and with vibrations utilized has been done. Furthermore, a theoretical model has been established to predict the tensile strength and plasticity of FFF parts fabricated without and with vibrations utilized based on classical laminated plate theory, with the anisotropic and laminated characteristics taken into consideration. Young's modulus model has been established based on the laminated plate theory and flexural vibration theoretical approaches of a plate for the PLA FFF parts manufactured without and with vibrations utilized respectively. Compared with the previous models this model provides the tensile strength and plasticity of FFF parts both manufactured without and with vibrations utilized. The results indicate that the predicted tensile strength and plasticity of the PLA FFF parts manufactured with vibrations utilized have a good consistency with the experimental ones, meanwhile, vibration utilization can significantly improve the surface quality of the PLA FFF samples manufactured in the Z-direction, and the scanning electron microscopy (SEM) analysis confirmed that vibration utilization can improve the forming quality of FFF manufactured parts.
... The concentration of NaOH in the liquid phase upon repulping of RM before carbonation was 0.05 mol L −1 , which corresponded to an equilibrium pH value of 10 ( Figure 1a). Although alumina production plants wash the RM before discharging it to extract NaOH and soluble Al, the pH value of the RM suspension after washing usually is within the range of 10− 13. 72 Distribution of alkali in the aqueous phase of the RM suspension is associated with the washing of a part of alkali and sodium aluminate adsorbed on the surface of the RM mineral particles, which in aqueous solutions is hydrolyzed with the formation of NaOH and Al 2 O 3 ·3H 2 O. It should be noted that exposure to water of some minerals, for example, sodium hydroaluminosilicates (DSP) such as sodalite ([Na 2 O·Al 2 O 3 · 2SiO 2 ]·qNaAlO 2 ·pH 2 O), which are present in RM, causes their hydrolysis with the formation of NaOH. ...
The carbonate leaching of scandium from the landfilled bauxite residue (red mud) of the Bogoslovsky Aluminum Plant (Russia) and samples of red mud (RM) after alkaline pretreatment has been investigated. The results of kinetic studies allowing to compare and evaluate the effectiveness of different conditions and intensification factors in the process of scandium leaching from RM in carbonate/bicarbonate media are presented. It was determined that for 2.0 mol L–1 Na2CO3 leaching solution ultrasonic treatment under gas (CO2) carbonation conditions in the pH range of 9.5–10.0 allows reducing the scandium leaching time by two times and reaching 40–45% scandium extraction. Leaching of RM in carbonate/bicarbonate media is accompanied by secondary processes (adsorption, hydrolysis, and coprecipitation) leading to a decrease in scandium extraction. The obtained results allow improving understanding of scandium chemical behavior in complex aqueous carbonate/bicarbonate systems and can be used for the optimization of the alternative carbonate process for scandium extraction from RM.
... In certain vibration amplitude the absorbed ultrasonic power increases with increasing insertion depth (SILVA et al., 2016). With increasing vibration amplitudes, cavitation and subsequent stressing of soil particles increases and causes more frequent fracture of soil particles (MAYER et al., 2002). Ultrasonic dispersion experiments at different vibration amplitudes and low absorbed energies may serve therefore to separate macroaggregates of different stability (SILVA et al., 2016, SILVA et al., 2019. ...
... Acoustic pressure waves are emitted into an aqueous suspension, which causes cavitation, stressing of soil aggregates and breaking of aggregate bonds (SCHOMAKERS et al., 2011). At higher vibration amplitudes, higher pressure waves occur and particle disruption is accelerated (MAYER et al., 2002). When the aggregates of BS treatment were exposed to a longer sonification time (6 seconds (Table 2). ...
... The ultrasonic power applied is significantly affected by the presence of soil, suspension concentration, suspension temperature and depth of probe insertion (RAINE; SO, 1994;SO, 1993;SILVA et al., 2016). The depth of immersion of the probe and the volume of the suspension were standardized for all treatments (MAYER et al., 2002;RIBEIRO et al., 2017), therefore, the cavitation intensity (amplitude) decreased due to the increase in the temperature of the suspension (RAINE; SO, 1994;MAYER et al., 2002). ...
Although they result in the same applied energy, certain combinations of time and power might correspond to different intensities of cavitation. Consequently, several responses in aggregation indexes can be obtained with different configurations of ultrasound techniques. Thus, this study aimed to evaluate the effects of cavitation intensity in the distribution of aggregates of a Paleudalf under management systems with cover plants and to compare aggregate stability determination methods (ultrasound versus wet sieving-WS). Aggregate samples of the treatments bare soil, black oat + forage turnips, and black oat + hairy vetch were exposed to ultrasonic irradiation in different combinations of potency and time: 74.5 W/4 s, 49.7 W/6 s, 74.5 W/10 s, and 49.7 W/15 s. The geometric mean diameter (GMD) and mass-weighted mean diameter (WMD) were calculated. The amplitude of vibration exerted a greater influence on soil breakdown than the total energy applied. In the WS method, we observed greater GMD and WMD.
... The principle of ultrasonic dispersion (sonification) is based on the cavitation phenomenon, releasing enough energy to destroy soil aggregates, causing dispersion even in highly aggregated soils (Mayer et al., 2002;Taurozzi et al., 2010;Ribeiro et al., 2017). The ultrasonic waves collide with the high strength aggregates formed by the Fe and Al oxides and promote their breakage in an integral way (Barral et al., 1998;Gee and Or, 2002;Gregorich et al., 1989;Ribeiro et al., 2009, 2017, Sá et al., 1999Schmidt et al., 1999;Silva et al., 2015Silva et al., , 2016Silva et al., , 2019Vitorino et al., 2003). ...
Our aim was to use the domestic microwave to dry different tropical soils with an iron oxide (Fe2O3) content in the clay fraction, as well as to disperse them using ultrasonic energy. We used nine soils with different Fe2O3 content in the clay fraction (31–662.6 g kg⁻¹) from horizons (A-Bi-Bw) of the Inceptisols and Oxisols in Brazil. The study was separated into two experiments: 1- soil drying time modeling (classic oven methods v. domestic microwave), 2- Soil dispersion: particle size and clay dispersed in water, by ultrasound energy v. standard method (NaOH 1 N + mechanical dispersion). Data were submitted to Gompertz non-linear regression model, ANOVA, Scott Knott's test, and Pearson's correlations. The domestic microwave was efficient for eigth soils studied, being limited when the Fe2O3 content exceeds 50%. The optimum drying time was between 30 and 40 min. The dispersion carried out by sonification, with the energy of 127.5 Jml⁻¹, in five minutes, increased the clay content, showing greater efficiency in relation to the standard dispersion method, in soils with high Fe2O3 content. The use of the domestic microwave and the ultrasonic to disperse the soil allows a particle size analysis to be carried out in one hour with good precision compared to the standard method.
... Soil aggregate stability is the soil's ability to cope with the external stresses applied to change its geometry of solid and pore spaces [1]. When the external forces dominates the internal binding forces, unstable aggregates split, eventually worsening the soil structure [2,3]. Aggregate stability is considered one of the leading quality assurance parameters of soil as it controls most of the physical, chemical and biological properties/functions of soil [4,5]. ...
... The ultrasonic agitation (UA) method is being used for decades to assess aggregate stability because of the fact that soil-water suspension could be used as a research object [6][7][8][9]. Another advantage of using ultrasonic agitation is that it can be used for soil stability assessment studies without using chemical-dispersing agents; this is particularly important when the study's objective would be to use the same soil samples for further chemical analysis [2]. Along with other merits over classical stability methods, ultrasonic agitation (UA) has an edge of providing the basis to calculate the arbitrary energy used for aggregate disruption [3]. ...
... This suspension was kept for 5 min, and the suspension was later exposed to sonication using the probe-type ultrasonic instrument UP100H (Hielscher Ultrasound Technology, Tetow, Germany), having a probe tip diameter of 10 mm, with an amplitude of 2 AM, power density of 90 Wcm 2 , and 20 kHz frequency. Based on the fixed initial temperature (by three temperature sensors) and input power (amplitude), six sonication durations of 0, 30, 60, 120, 210, and 300 s were used to evaluate the effect of soil aggregate disruption at various energy levels (normally, applied ultrasonic power and temperature of soil-water suspension increase with increasing sonication duration) [2,[23][24][25]. To differentiate various soils, dispersion energy (E l ) was calculated as suggested by Zhu et al. [11] as follows: ...
s soil stability is a complex phenomenon, various methods and indexes were introduced to assess the strength of soils. Because of the limitations of different stability methods and indexes (including wet sieving-based), we aimed to presents a relative stability index (RI) that was based on the estimated components of the soil overall disruptive characteristic curve (SODC): (1) soil disruption constant (Ki, that is based upon dispersion energy of soils); (2) resulting change in mean weight diameter (ΔMWD). To evaluate the effectiveness and limitations of RI as well as to compare it with classical soil stability indexes of mean weight diameter (MWD) and geometric mean diameter (GMD). Ultrasonic agitation (UA) along with a wet sieving method (followed by dry sieving) was applied against four different soils named on the basis of sample location, Qingling soil (QL), Guanzhong soil (GZ), Ansai soil (AS), and Jingbian soil (JB). To evaluate the relative strength of soils at different applied energies (increase in sonication duration usually resulted in increased input energy and temperature of soil–water suspension), soils were subjected to six sonication durations (0, 30, 60, 120, 210, and 300 s) with a fixed (and exact) initial amplitude and temperature. Output energy was calculated based on the amplitude and temperature of the suspension, vessel, and system. The most abrupt and maximum disruption of soil aggregates was observed at a dispersion energy level of 0–200 J g−1. The MWD value of surface and subsurface ranged between 0.58 to 0.15 mm and 0.37 to 0.17 mm, respectively, while GMD was ranged from 0.14 to 0.33 mm overall. The results for MWD and GMD showed a similar trend. MWD and GMD showed more strong associations with physicochemical characteristics of soil than RI. A non-significant correlation was found between RI and MWD/GMD. Contrary to MWD and GMD, RI was significantly positively correlated with sand content; this finding indicated the influential role of sand in assessing the soil’s relative strength. The results indicated that JB soil possessed the least MWD and GMD but proved to be relatively stable because of having the highest RI value.
... The sand was physically separated with a 63 μm sieve (Forshythe, 1974). The remaining supernatant suspension was dispersed with ultrasonic vibrations for five minutes (Schallfix, ultrasound stem, 120.000 rpm) and silt and clay soil fractions were separated by decantation (Mayer et al., 2002). Subsequently, in the separated clay-sized material the residual organic C contents were measured using Walkley and Black methodology by wet digestion (Sadzawka, 1990). ...
The chemical interactions between soil clay-sized mineral fractions and soluble organic compounds are mainly the result of soil sorption mechanisms into reactive sites. The ability of clay-size fractions from different Chilean soil groups to protect leucine from microbial decay was used as an index of the retention of soluble organic matter by soil mineral fractions. The reactivity of clay-sized mineral fractions was determined by extractable Al in ammonium acetate 1M, pH 4.8; acid ammonium oxalate 0.2 M; sodium pyrophosphate 0.1 M and pH levels in NaF. Leucine retention provided by the clay-sized mineral fraction was estimated by determining the amount of leucine remaining after a 24 h period of incubation post-application of leucine to soil mineral fractions under controlled conditions. The slope of non-linear regression (ratio between added versus recovered) reflects the different chemical protection capacities of the materials evaluated, where b values were 0.001, 0.021, 0.043, 0.124, 0.128 and 0.259 for quartz sand, smectite, kaolinite, halloysite, volcanic-glass and allophane, respectively. We found that the leucine retention index was related to the clay-sized reactive fraction for all the soil groups evaluated (R 2 > 0.75). Thus, within the range used (up to 1480 mg kg-1 of leucine applied), the recovery was related to the amount of aluminium extracted with ammonium acetate 1M (R 2 = 0.96). Clay-sized mineral fractions with greater reactivity, due to their dominant colloid fraction (clay-sized mineral fractions plus residual SOC), expressed bigger leucine protection to microbial decay.
... Thus, soil fractionation procedures, which comprise ultrasonic dispersion, often give a fixed amount of energy that should be applied to achieve a certain degree of aggregate breakdown . In contrast, few studies have investigated the effect of ultrasonic power on the breakdown of aggregates (Mayer et al., 2002) and it has been widely ignored that varying time and power (or vibration amplitude) to achieve the same amount of energy might lead to significantly different results. This is a minor problem if the total dispersion of aggregates should be achieved, since this is often calibrated with a chemical dispersion. ...
Organischer Bodenkohlenstoff (SOC) ist der größte terrestrische Kohlenstoff (C)-Pool, welcher ein Vielfaches des gesamten atmosphären C speichert. Landwirtschaftliche Nutzung von Böden hat einen starken Einfluß auf diesen Speicher und so auch auf C-Flüsse zwischen Atmosphäre und Biosphäre. Historsich haben Landnutzungsänderungen zu starken CO2-Emissionen aus Böden geführt, was auch einen signifikanten Einfluß auf die globale Erwärmung hatte. Diese kumulative Habilitationsschrift fokusiert auf zwei Haupteinflüsse des Menschen auf SOC: Landnutzung und globale Erwärmung durch Treibhausgasemisionen. Beide sind mit der globalen Ausbreitung des Menschen und der sprunghaften Entwicklung dessen Aktivität auf Erden stark angestiegen und werden somit als spezifisch für das „Anthropozän“ erachtet, welches hier als Synonym für jene Periode in der Weltgeschichte benutzt wird, in der menschliche Aktivität irreversible Spuren hinterlassen hat.. Durch die große Bedeutung von SOC und dessen Management für den Klimawandel, aber auch für Bodenfruchtbarkeit und Resilienz von Ökosystemen, ist es wichtig zu verstehen, i) welche Management-Optionen SOC erhalten und vermehren können ii) welche Mechanismen zu dessen Verlust und Stabilisierung führen, iii) wie die globale Nettoprimärproduktion auf möglichst nachhaltige und klimafreundliche Weise genutzt werden kann und iv) wie die globale Erwärmung C-Vorräte im Boden beeinflussen wird. Zusammen mit einigen methodischen Aspekten, welche zu einer verbesserten Messung, Berechnung und Modellierung von SOC beitragen sollen, bilden jene Themenomplexe den wissenschaftlichen Fokus dieser Arbeit.
... For chernozem, the lowest ergosterol concentration was observed with the simple shaking extraction as shown in Fig. 1. A high degree of turbidity in the extracted solution, which leads to the requirement for more purification steps, by ultrasonic assisted methods, may be the result of the effectiveness of ultrasonication in soil dispersion (Mayer et al., 2002;Mentler et al., 2004). Therefore, the optimization of the extraction conditions for the physical cell disruption assisted methods e.g., disruption duration and energy input, will enhance extraction ability. ...
Concerning the contribution of fungi to soil carbon sequestration, various methods have been used to extract ergosterol from soil samples. This study aims to explore the extraction ability and applicability of commonly used methods to extract ergosterol from two contrasting soils. An agricultural soil (chernozem) and a forest soil (podzol) were extracted with different types of cell lysis such as alkaline, glass bead, and ultrasonication methods in association with simple shaking. The ergosterol concentration was measured by high pressure liquid chromatography. Regardless of the method applied, ergosterol yield was higher in podzol than in chernozem. Alkaline extraction resulted in the highest ergosterol concentrations for both soils and miniaturized glass bead extraction produced comparable results in the case of chernozem. In terms of applicability, the non-alkaline methods were simpler to conduct and less demanding of labour, chemical use and glassware and more flexible in terms of the equipment used for mechanical disruption. Despite the limit of the two soil types in the present study, only the simple shaking method was revealed to be dependent on soil type. Based on our results, we recommend the miniaturized glass bead method for agricultural soils, low in organic matter for high throughput. However, not all of the methods described allow for the proper separation of co-extracted organic substances from organic-rich soil.
... All soils were tested at constant vibration amplitude of the ultrasonic probe of 2.5 μm for 30 s. As reported in the literature (Mayer et al. 2002;Mentler et al. 2004), the vibration amplitude was determined using electromagnetic induction coil and strain gauges. Immediately after the ultrasonic treatments, mass fractions were determined by wet sieving. ...
In this study, the effects of innovative and traditional thinning on soil properties with respect to unmanaged forest were assessed with the aim to individuate early warning indicators of soil erosion for identifying the most appropriate forestry practices to sustainably manage an Italian beech (Fagus sylvatica) forest. Soil organic carbon (OC), microbial biomass C (MBC), ergosterol (ERG), humification rate, water-soluble phenols (WSP), fluorescein diacetate (FDA) hydrolysis, dehydrogenase (DHA) and catalase activities (CAT), ultrasonic aggregate stability and ¹³⁷Cs were detected to asses soil health and erosion magnitude. The aim was to correlate ¹³⁷Cs, as a basic indicator of soil erosion rate, with soil aggregate stability and biological activity parameters. ¹³⁷Cs results evidenced that both thinning treatments affected soil properties. The innovative treatment showed the highest impact. The amount of small-sized particles enhanced when the intensity of thinning increased. A strong decrease in soil OC was related to thinning. In the upper soil layer, OC was found positively correlated with MBC, FDA, WSP, ERG, C/N, N and also with ¹³⁷Cs. Moderate to no correlations, in the subsurface layer, highlighted the immediate impact of management techniques on the surface layer and then on the underlying ones. In the subsurface layer, OC maintained its positive correlation only with MBC, WSP and ¹³⁷Cs. ¹³⁷Cs was correlated in both soil layers with OC, N and WSP. The overall results suggest that the latter parameters may be considered as indicators of soil erosion. More specifically, WSP can be used, even in the case of the absence of ¹³⁷Cs in the sediment, to evidence changes in soil properties that could be the starting point of soil fertility loss.
... In addition to sonication energy, several other factors are known to affect the sonication efficiency and may impact aggregate disruption. Oscillation frequency or amplitude influence the cavitation effect (Christensen, 1992;Mayer et al., 2002;Mentler et al., 2004) and, thus, could affect the extent of disruption of soil aggregates per applied sonication energy unit. The geometry of the oscillating tip (Schomakers et al., 2011) may also influence the extent of aggregate disruption since the tip surface area determines the spatial structure of the pressure field in the suspension. ...
... This is because a large portion of instable aggregates > 63 μm are disrupted already after application of energies < 30 J mL -1 in most soils. Both highlighted factors, oscillation frequency and sonotrode diameters, were suggested to affect aggregate disruption results by Christensen (1992), Amelung and Zech (1999), Mayer et al. (2002), Mentler et al. (2004), and Schomakers et al. (2011). These effects, as shown by our results, seem to be small for the soils and conditions tested here. ...
Sonication is widely used for disruption of suspended soil aggregates. Calorimetric calibration allows for determining sonication power and applied energy as a measure for aggregate disrupting forces. Yet other properties of sonication devices (e.g., oscillation frequency and amplitude, sonotrode diameter) as well as procedure details (soil‐to‐water ratio, size, shape, and volume of used containers) may influence the extent of aggregate disruption in addition to the applied energy. In this study, we tested potential bias in aggregate disruption when different devices or procedures are used in laboratory routines. In nine laboratories, three reference soil samples were sonicated at 30 J mL−1 and 400 J mL−1. Aggregate disruption was estimated based on particle size distribution before and after sonication. Size distribution was obtained by standardized submerged sieving for particle size classes 2000–200 and 200–63 µm, and by dynamic imaging for particles < 63 µm. Despite differences in sonication devices and protocols used by the participants, only 16 in 216 tests of samples of the size fractions 2000–200 and 200–63 µm were identified as outliers. For the size fraction < 63 µm, fewer outliers were detected (8 in 324 tests). Four out of nine laboratories produced more than two outliers. In these laboratories, sonication devices differed from the others regarding oscillation frequencies (24 or 30 kHz compared to 20 kHz), sonotrode diameters (10 and 14 mm compared to 13 mm), and sonication power (16 W compared to > 45 W). Thus, these sonication device properties need to be listed when reporting on sonication‐based soil aggregate disruption. The overall small differences in the degree of disruption of soil aggregates between different laboratories demonstrate that sonication with the energies tested (30 and 400 J mL−1) provides replicable results despite the variations regarding procedures and equipment.
