Electro-osmosis on anisotropic super-hydrophobic surfaces

We give a general theoretical description of electro-osmotic flow at striped super-hydrophobic surfaces in a thin double layer limit, and derive a relation between the electro-osmotic mobility and hydrodynamic slip-length tensors. Our analysis demonstrates that electro-osmotic flow shows a very rich behavior controlled by slip length and charge at the gas sectors. In case of uncharged liquid-gas interface, the flow is the same or inhibited relative to flow in homogeneous channel with zero interfacial slip. By contrast, it can be amplified by several orders of magnitude provided slip regions are uniformly charged. When gas and solid regions are oppositely charged, we predict a flow reversal, which suggests a possibility of huge electro-osmotic slip even for electro-neutral surfaces. On the basis of these observations we suggest strategies for practical microfluidic mixing devices. These results provide a framework for the rational design of super-hydrophobic surfaces.Comment: 4 pages, 4 figures; submitted to PRL Revised version: several references added, typos corrected. Supplementary file was restructured, the second part of the original EPAPS was removed and is supposed to be published as a separate pape

Application of Crowdsourcing Technology In Terms Of Digitization of Supply Chain Strategy

Abstract— The article presents the study on the problem of crowdsourcing application in terms of digital development of supply chain strategy. The purpose of this study is to develop the algorithm of application of crowdsourcing technology in terms of digitalization of supply chain strategy in socio-economic processes. The application of crowdsourcing technology facilitates the search for the most effective solutions to enterprise’s problems, minimizing the time-related and financial costs for their development. In the framework of this study, the methods of analysis, comparative analysis, generalization, decomposition were used. The novelty of the research is in the detailed examination of the crowdsourcing technology, comprehensive description of the algorithm of its functioning with application in addressing various tasks of supply chain strategy. The findings of the study can help enterprises to elaborate the workflow supply chain management with regard to public opinion

The mechanical treatment as a method of Inorganic substances passive

The mechanopassivation effect of metal (II) oxides crystallizing by the structural type of halite under attrition treatment has been found out. For the assessment of the activity decrease the following has been investigated: solution and aquation kinetics of CaO and MgO in water and solutions; spinel and calcium carbide formation kinetics using oxides pretreated mechanically by different modes; kinetics of CO2 fixation and thermal desorption from the pretreated oxides surface; magnesia and phosphate cements set rate. It has been determined that the rate of studied processes with the participation of oxides subjected to attrition treatment reduces by a factor of tens and hundreds. We suppose the cause to be the removal of the rough loosened layers containing the most of defects from the polycrystalline aggregates surface. As that neighboring zones accommodate, their surfaces flatten and the bonding area rises. Separated smallest particles form compact aggregates. The powder density increase and sharper diffraction reflection form confirm the microstructure regulating. Flat surfaces with lower quantity of defects provoke the hypoactivity in regard to water vapors and carbon dioxide. The substances mechanopassivation study can be used to control the reaction rate with the participation of highly active reagents

Brownian motion near a partial-slip boundary: A local probe of the no-slip condition

Motivated by experimental evidence of violations of the no-slip boundary condition for liquid flow in micron-scale geometries, we propose a simple, complementary experimental technique that has certain advantages over previous studies. Instead of relying on externally-induced flow or probe motion, we suggest that colloidal diffusivity near solid surfaces contains signatures of the degree of fluid slip exhibited on those surfaces. To investigate, we calculate the image system for point forces (Stokeslets) oriented perpendicular and parallel to a surface with a finite slip length, analogous to Blake's solution for a Stokeslet near a no-slip wall. Notably, the image system for the point source and perpendicular Stokeslet contain the same singularities as Blake's solution; however, each is distributed along a line with a magnitude that decays exponentially over the slip length. The image system for the parallel Stokeslet involves a larger set of fundamental singularities, whose magnitude does not decay exponentially from the surface. Using these image systems, we determine the wall-induced correction to the diffusivity of a small spherical particle located `far' from the wall. We also calculate the coupled diffusivities between multiple particles near a partially-slipping wall. Because, in general, the diffusivity depends on `local' wall conditions, patterned surfaces would allow differential measurements to be obtained within a single experimental cell, eliminating potential cell-to-cell variability encountered in previous experiments. In addition to motivating the proposed experiments, our solutions for point forces and sources near a partial-slip wall will be useful for boundary integral calculations in slip systems.Comment: 34 pages, 5 figure

The Use of Visual Perceptual Tasks for Study of Cognitive Processes in Anankastic Personality Disorder and Pseudoneurotic Schizophrenia

The aim of present research was to investigate the performance of visual perceptual tasks with varying the degree of uncertainty and levels of regulation prescribed by vague, verbal and non-verbal instructions. The modified Witkin test and Wechsler Adult Intelligence Scale, a revised form (WAIS-R) were used. 36 anankastic personality disorder patients (mean age-31,9±9,8 years), 38 schizophrenic patients (pseudoneurotic type, mean age 30,8±8,7 years) and 100 healthy controls (mean age 27,5±8,5 years) were enrolled to the study. It was established that the effectiveness of the performance of visual perceptive tasks in conditions of vague instruction did not differ among the subjects of all three groups. The introduction of additional verbal instruction increased the performance of healthy subjects and patients with anankastic personality disorder, in contrast to patients with schizophrenia. In conditions of nonverbal instruction, the effectiveness of performing was reduced in clinical and control groups, but the parameters of healthy subjects were significantly higher (р≤0,05). It was found in schizophrenia an increase in the number and strength of the correlation between the indices of the performance of visual perceptual tasks and the non-verbal parameters of Wechsler Adult Intelligence Scale

Studying the Effectiveness of Teacher Training in Organization of Open Education

The modern concept of open education modifies the traditional learning format through advanced information and communications technology. This fact imposes special requirements for all participants in the learning process and makes it necessary to reconsider the tasks and functions of students and teachers. This is relevant, therefore, to find a way of making a gradual transition to the model of open education. Based on an experiment with introductory training, the authors perform an empirical assessment of teachers’ preparedness to organize open education and use open educational resources (OER). The effectiveness of the introductory training of teachers was checked by means of interviewing and testing respondents. The research results showed that there were significant changes in the training criteria: according to the motivational and value-based criterion, virtually all teachers displayed a positive shift in their attitude to organization of open education; in terms of the cognitive criterion, the teachers acquired thorough knowledge of open education tools; according to the operational criterion, the teachers acquired the necessary skills in developing and introducing OER. In the process of observation, we recorded a rise in the number of teachers with a sufficient (by 60.5% compared with the verification stage) and high (by 16.6%) level of preparedness. The introductory training, therefore, is a principal component in the stable system of open education

A method for calculating the productivity of cable communications networks

A probabilistic-mathematical instrument was used to develop a method fo

Lattice Boltzmann simulations in microfluidics: probing the no-slip boundary condition in hydrophobic, rough, and surface nanobubble laden microchannels

In this contribution we review recent efforts on investigations of the effect of (apparent) boundary slip by utilizing lattice Boltzmann simulations. We demonstrate the applicability of the method to treat fundamental questions in microfluidics by investigating fluid flow in hydrophobic and rough microchannels as well as over surfaces covered by nano- or microscale gas bubbles.Comment: 11 pages, 6 figure