Movable Volume Research Articles

Triboelectric nanogenerator-based self-powered two-dimensional microfluidic system for biochemical reaction

Microfluidic systems for biochemical reactions require efficient microfluidic actuation. However, current microfluidic devices are facing challenges in terms of self-powering and precise transport of microfluidics. This study demonstrates a novel approach to fabricating a self-powered and precise microfluidic manipulation system based on triboelectric nanogenerator (TENG) and electrowetting-on-dielectric (EWOD) technologies. The TENG provides high pulsed voltage and electrical wetting capabilities, enabling the manipulation system to drive microfluidic transport through electric field forces. The self-powered microfluidic device is systematically investigated by the effect of various parameters, including TENG power, TENG structures, EWOD/microfluidic device structures and surface hydrophobic properties. By optimizing the parameters, optimal performances are achieved in microfluidic motion, particularly in terms of precise two-dimensional movement. The movable volume range spans from 20 nl to 1.4 ml, representing one of the most notable achievements of TENG in the field so far. Additionally, the self-powered microfluidic system successfully synthesized multiple morphological ZnO nanoparticles, a rarely reported accomplishment. Finally, the novel self-powered system demonstrates the capability to detect chloride in disinfected water and COVID-19 antigen detection. This work proposes a novel TENG-EWOD microfluidic control technology that shows promise in various applications, including chemical processes, biological health testing and microdevice fabrication.

Estimating the debris-flow magnitude using landslide sediment connectivity, Qipan catchment, Wenchuan County, China

In an earthquake disturbed basin, the earthquake-induced landslides’ connectivity with debris-flow channels determines the landslide sediment volume that is transported into debris flows, and the debris-flow magnitude as well. In this study, the index of sediment connectivity (IC) was used to analyze the evolution of landslide sediment transport capacity. A normalized IC was developed to quantify the movable volume of the landslide sediment available for debris flows. Combined with a landslide empirical relationship, sediment connectivity calculation, particle model, and numerical algorithm, two debris-flow events after the 2008 Wenchuan earthquake were simulated for the Qipan catchment. The results show good agreement between the simulated and observed debris-flow magnitudes of peak discharges, inundated areas, and depths with approximately 9% average error, which indicates that the normalized landslide connectivity index is suitable for estimating the movable volume. Moreover, the IC and landslide characteristics (area and location) showed significant negative correlations, indicating that the spatial connectivity of landslide sediment generally decayed over time, with a corresponding reduction in debris-flow magnitude.

IDENTIFIKASI GLIKOSIDA DAN EVALUASI FISIK FORMULA PEMANIS RENDAH KALORI TANAMAN STEVIA (Stevia rebaudiana Bentoni) PADA MINUMAN FUNGSIONAL BIR PLETOK

Instant drinks, which are often consumed by the public, are mostly sweetened drinks that contain high calories and artificialsweeteners and can cause various diseases, such as obesity, cancer, diabetes and others. This can be controlled and prevented by consuminglow-calorie sweeteners. Stevia is a plant that has a sweetness of 300 times that of sucrose, so it can be used as a low-calorie sweetener, suchas in the functional drink Pletok beer. This study aims to identify glycosides and to evaluate the physical evaluation of the low-caloriesweetener formula for Stevia (Stevia rebaudiana B.) in the functional beverage of Bir Pletok. Physical evaluation and hedonism test werecarried out on 20 panelists and 1 expert panelist, then analyzed descriptively. In this study, several tests of instant preparations were carriedout, namely organoleptic test, pH test, specific gravity test, movable volume test and hedonism test on 20 panelists and 1 expert panelist. Theresults of the research that have been done show that the leaves of Stevia (Stevia rebaudiana B.) contain diterpenoid glycosides and based onall test preparations the best formula of the three formulas is Formula II. Keywords: Sweeteners, Stevia, Functional Drinks, Bir Pletok, Glycosides.

A deep scar in the flank of Tenerife (Canary Islands): Geophysical contribution to tsunami hazard assessment

Among the high-intensity on-Earth tsunami generating events, seismicity, submarine landslides, and volcano lateral collapses are the most important [Ward, S.H., 2001. Landslide tsunami. J. Geophy. Res. 106, 11201–11215; Holcomb, R.T., Searle, R.C., 1991. Large landslides from oceanic volcanoes. Mar. Geotech. 10, 19–32; Tinti, S., Bortolucci, E., Romagnoli, C., 2000. Computer simulations of tsunamis due to the sector collapse ar Stromboli, Italy. J. Volcano. Geotherm. Res. 96, 103–128; Ward, S.N., Day, S., 2003. Ritter Island Volcano — lateral collapse and the tsunami of 1888. Geophys. J. Int. 154, 891–902; MacGuire, W.J., 2003. Volcano instability and lateral collapse. Revista 1, 33–45]. Offshore bathymetry studies highlighted huge accumulations of large mass-waste flows (up to thousands cubic kilometres) inherited from past lateral collapses or submarine landslides [ Le Friant, A., Boudon, G., Deplus, C., Villemant, B., 2003. Large-scale flank collapse events during the activity of Montagne Pelée, Martinique, Lesser Antilles. J. Geophys. Res. 108, ECV13; Moore, J.G. et al., 1989. Prodigious submarine Landslides on the Hawaiian ridge. J. Geophys. Res. 94, 17465–17484] which spread over more than 100 km off the northern Tenerife (Canary Islands) coastline [Watts, A.B., Masson, D.G., 1995. A giant landslide on the north flank of Tenerife, Canary Islands. J. Geophys. Res. 100, 24487–24498]. Although mechanics and dynamics triggering such catastrophic events follow from combined complex processes and interactions [Hürlimann, M., Garcia-Piera, J.-O., Ledesma, A., 2000. Causes and mobility of large volcanic landslides: application to Tenerife, Canary Islands. J. Volcano. Geotherm. Res. 103, 121–134; Masson, D.G. et al., 2002. Slope failures on the flanks of the western Canary Islands. Earth-Sci. Rev. 57, 1–35; Reid, M.E., Sisson, T.W., Brien, D.L., 2001. Volcano collapse promoted by hydrothermal alteration and edifice shape, Mount Rainier, Washington. Geology 29, 779–782], potential movable volume is an unavoidable parameter to quantify and constrain tsunamigenic hazard. Numerical modelling of a tsunami generated by the potential La Palma landslide concluded that high amplitude waves threaten North Atlantic shorelines [Ward, S.N., Day, S.J., 2001. Cumbre Vieja volcano — Potential collapse and tsunami at La Palma, Canary Islands. Geophys. Res. Lett. 28, 397–400]. New audiomagnetotelluric results provide for the first time a good estimation of the Icod Valley (Tenerife, Canary Islands) volume, a potential giant landslide threatening the same shorelines. Two profiles image its electrically conductive roots with a characteristic of a U-shaped cross-section thought to be the consequence of previous landslides. By this study, we show that North Atlantic Ocean shorelines might be exposed to a destructive tsunami generated by a subaerial lateral collapse of at least 120 km 3 during the next strong felsic eruptive activity of the Teide–Pico Viejo complex. This article highlights the degree of urgency of carrying out geophysical investigations on the flanks of most volcanic islands prone to potential flank collapse. These investigations will contribute to the understanding of their structure — a key parameter in the sliding process. Finally, all results should be included in model, providing a global map of tsunami hazard assessment.

Exponential decay of critical current in Y-Ba-Cu-O: relationship with the pinning potential profile and its physical origin

An exponential decay of critical current density has been reported by several authors for high-temperature superconductors in the configuration H ‖ c . In order to give an interpretation of this behavior, we suggest that it is related to a specific profile of the pinning potential U p( R) acting on the vortices. For planar defects, consideration of the kinetic energy associated with supercurrents flowing around the vortex core leads to a logarithmic dependence of U p( R). We then follow the general hypothesis of flux creep models with non-linear U p( R), in the limit of direct summation for the elementary pinning forces. In this framework, we show that a logarithmic dependence of the pinning potential on the defect-vortex distance leads to the experimentally observed critical current decay. Low-temperature values of the critical current density and of the V c X product (the “movable volume” times the pinning potential width) obtained in Y-Ba-Cu-O compounds are analyzed in this model from a qualitative point of view.

Simulation of the Alcohol-Slug Process Using the "Cell Model"

Abstract The similarity of the mechanism of miscible displacement to the functioning of packed columns has led to suggestions that the "theoretical plate" concept might be a useful mathematical model for the simulation of miscible displacement processes. Such a model would rest on the assumption that the porespace of a linear porous medium is equivalent to a certain number of "plates"or cells and that, in each cell, only a fraction of the fluid volume ismovable. During displacement, the movable volume from each cell moves on toeach succeeding cell, establishing equilibria with the respective stationary volumes. When two phases are present in the model, relative phase mobilities, as governed by viscosities and phase saturations, will affect the movable fractionin each cell. If, in addition, there is interphase transfer of material, the equilibrium condition for each cell is governed by the amounts and mutual solubilities of the components. While the procedure is quite general, thepresent study is confined to various ternary water-hydrocarbon-alcohol systems.To expedite computations, general mathematical relations were developed for thebinodal curves and tie lines. These were necessary to obtain the phase volumes and compositions for any over-all cell composition. Expressions for phasemobility ratios as functions of saturations were also used. The validity of the model has been demonstrated by comparisons of efflux histories for alcohol displacements of oil and water as obtained from the model and from laboratory experiments. Introduction It has been known for some time that a sufficient volume of certain lower alcohols will effectively displace all or most of the oil and water contacted in an oil-water porous medium system. As alcohols are considerably more expensive than equal volumes of recovered oil, an economically successful process requires that only a finite volume or slug of alcohol displace the oil and water.