Marangoni effect inspired robotic self-propulsion over a water surface using a flow-imbibition-powered microfluidic pump

Certain aquatic insects rapidly traverse water by secreting surfactants that exploit the Marangoni effect, inspiring the development of many self-propulsion systems. In this research, to demonstrate a new way of delivering liquid fuel to a water surface for Marangoni propulsion, a microfluidic pump driven by the flow-imbibition by a porous medium was integrated to create a novel self-propelling robot. After triggered by a small magnet, the liquid fuel stored in a microchannel is autonomously transported to an outlet in a mechanically tunable manner. We also comprehensively analyzed the effects of various design parameters on the robot’s locomotory behavior. It was shown that the traveled distance, energy density of fuel, operation time, and motion directionality were tunable by adjusting porous media, nozzle diameter, keel-extrusion, and the distance between the nozzle and water surface. The utilization of a microfluidic device in bioinspired robot is expected to bring out new possibilities in future development of self-propulsion system.

Method for microscopic monitoring of homeopathic medicines

We described microscopic observation of the effects of potentiation for the first time in 2002, and presented the results at the 2013 GIRI meeting. The study continued with the development of a visual quality control method using optical microscopy. The theoretical grounds underlying this method derive from high dilution research conducted by Komissarenko [1,2]. A ‘crushed’ drop is prepared from a potentized agent with one drop of black ink for microscopy with 20 and 40 magnification. Control consisted in a similarly of a drop of water and a drop of black ink. Visual estimates were performed according to the nature of the black ink particle movement, considering spin rate, randomness severity and/or motion directionality. Specimens were animal, vegetable and mineral origin, in cultivations from 1 to 1500 сH prepared by different manufactures from 1995 to 2016. For many years we looked for a way to visualize the ink particle motion under microscope by means of video files. However, this procedure proved to be too difficult from the technical point of view. Now this problem is solved. Thanks to the collaboration of specialists from St. Petersburg and Russia, a number of video files could be made, that demonstrate the difference of the particle motion black ink in various homeopathic remedies. In this presentation, we will show video files depicting the Brownian motion of ink particles in water and diluted up to 1500cH. All samples had characteristic patterns of ink micro particles motion that were different between control and test samples and also between test samples of previous and consequent dilutions. Gradual acceleration of micro particles spin is observed in samples from 1 to 10 сH. The movement remains chaotic. Spin velocity stops increasing from 10 сH to 30 сH, however movement of particles becomes unidirectional. This effect continues to increase in other samples up to 1500 сH. No gaps/leaps of these effects were found in consecutive survey of homeopathized remedies of 1 to 1500 сH. These changes are the same in all the investigated homeopathic medicines. The observed phenomenon was so significant, that we could distinguish the level of potentiation of the various homeopathic preparations. The directed motion of ink particles in potentized solutions fades when in storage. The molecular motion becomes chaotic again, i.e., it recovers the Brownian pattern when the solutions are agitated. A few shakes are sufficient to completely reconstruct the typical pattern of the original homeopathic preparation. In destroyed homeopathic medicines the pattern of chaotic motion of particles of ink is preserved irrespective of the amount and strength of agitation. The method of visual quality control described here easily solves issues related with the performance, storage and use peculiarities of homeopathic medicines. To conclude, effects of potentiation can be detected under optical microscopy. The method is simple to perform and allows distinguishing homeopathic medicines in a reliable manner. Therefore, this technique has potential for application in practice and research.

Within-Station Variability in Kappa: Evidence of Directionality Effects

ABSTRACT One of the most commonly used parameters to describe seismic attenuation is the high-frequency spectral decay parameter Kappa (κr), yet the physics behind it remain little understood. A better understanding of potential factors that lead to large scatter in estimated values of κr constitutes a critical need for ground-motion modeling and seismic hazard assessment at large. Most research efforts to date have focused on studying the site-to-site and model-to-model variability of κ, but the uncertainties in individual κr estimations associated with different events at a selected site (which we refer to as the within-station variability of κr) remain uncharacterized. As a direct corollary, obtaining robust estimates of the site-specific component κ0, and their corresponding interpretation become a challenge. To understand the sources of the variability observed in κr (and κ0) at a single site, we select 10 Japanese Kiban–Kyoshin network (KiK-net) downhole arrays and investigate the systematic contributions from ground-motion directionality. We observe that κr estimated from a single horizontal component is orientation dependent. In addition, the influence of ground-motion directionality is a function of local site conditions. We propose an orientation-independent κr-value, which is not affected either by ground-motion directionality or by the events’ azimuths. In addition, we find that focal depth of events used in κr calculations affects the estimation of the regional attenuation component κR, which, in turn, influences the within-station variability in the κ0 model.