"There are no such things as applied sciences, only applications of science."
The paper of Dr. Yuriy Polyakov, USPolyResearch, and Dr. Andrew Zydney, Pennsylvania State University, presenting latest mathematical models for protein ultrafiltration is published in Journal of Membrane Science, leading journal in membrane science [Polyakov, Yu. S. and Zydney, A. L., "Ultrafiltration membrane performance: Effects of pore blockage / constriction", Journal of Membrane Science, 2013, Vol. 434, pp. 106-120].
Abstract: Several recent studies have quantified the performance characteristics of ultrafiltration membranes in terms of the inherent trade-off between the membrane selectivity and permeability. However, none of these studies have accounted for the effects of membrane fouling on the evolution of the selectivity and permeability during typical ultrafiltration processes. This review paper examines a range of available fouling models, including the classical pore blockage / pore constriction models as well as newer models based on depth filtration and solute adsorption, with a particular focus on understanding the effects of these fouling phenomena on the permeability – selectivity tradeoff. Although fouling always causes a reduction in permeability, the selectivity can actually increase, e.g., if the larger (less selective) pores are preferentially blocked during ultrafiltration or if the pores are constricted by the foulants. The evolution of the permeability – selectivity tradeoff can be quite complex, depending on both the underlying fouling mechanism as well as the distribution of pore and solute sizes. These results provide new insights into. the behavior of ultrafiltration processes
The paper of USPolyResearch scientists and their colleague at MIT/Harvard University proposing a new classification for the black hole binary system GRS 1915+105 is published in The Astronomical Journal, one of world's leading journals in astronomy/astrophysics [Polyakov, Yu. S., Neilsen, J., and Timashev, S. F., "Stochastic Variability in X-Ray Emission from the Black Hole Binary GRS 1915+105" [arXiv:1204.3690v1], Astronomical Journal, 2012, Vol. 143, No. 6, 148].
Conceptual summary of the paper: Stochastic variability in the dynamics of X-ray emission from the black hole system GRS 1915+105, a strongly variable microquasar commonly used for studying relativistic jets and the physics of black hole accretion, is examined. Four modes of stochastic variability driven by dissipative processes that may be related to viscosity fluctuations in the accretion disk around the black hole: random (RN), power-law (1F), one-scale (1S), and two-scale (2S), are identified.
The paper of USPolyResearch scientists and their colleagues proposing a novel diagnostic method for schizophrenia based on the analysis of encephalograms is published in Physica A, one of the most prestigious physical journals in the world [Timashev, S. F., Panischev, O. Yu., Polyakov, Yu. S., Demin, S. A., and Kaplan, A. Ya., "Analysis of Cross-Correlations in Electroencephalogram Signals as an Approach to Proactive Diagnosis of Schizophrenia" [arXiv:1107.1884v2], Physica A, 2011, doi:10.1016/j.physa.2011.09.032].
Highlights of the paper:
- A diagnostic sign of schizophrenia in electroencephalogram (EEG) signals is identified
- EEG signals for 84 children/adolescents and study cross-correlations are parameterized
- Frequency–phase synchronization (FPS) plays an essential role in neural activity
- Deviation of the FPS level from norm can be used to identify pathological changes
- 84 subjects are partitioned into 4 groups characterizing risk levels for schizophrenia
The paper of USPolyResearch scientists and their colleagues proposing a novel nanometrological method to characterize the surface texture of technological nanosurfaces is published in Analyst, world's leading journal in analytical nanoscience [Mirsaidov, U., Timashev, S. F., Polyakov, Yu. S., Misurkin, P. I., Musaev, I., and Polyakov, S. V., "Analytical Method for Parameterizing the Random Profile Components of Nanosurfaces Imaged by Atomic Force Microscopy" [http://arxiv.org/abs/1010.6232v1],
Analyst, 2011, Vol. 136.]
Conceptual summary of the paper: Future progress in electronics, biochip technology, materials science, and many areas of nanotechnology depends to a large degree on the functional properties of nanoscale technological surfaces. The relations between functional properties and manufacturing conditions of nanoscale surfaces are studied by nanometrology, a branch of nanoscience dealing with surface texture analysis at nanoscales. In this study, we propose a novel nanometrological method to characterize the surface texture of technological surfaces imaged with atomic resolution, which captures the effects of surface irregularities associated with molecular and intermolecular interactions (functional activity of nanosurfaces). The method is successfully applied to estimating the effect of manufacturing process temperature on the corrosion-resistance properties of magnetite coatings on low-carbon steel. Potential applications of the method to thin semiconductor films, coatings for biochip substrates, catalytic coatings, frictional and adhesion contacts, and other nanotechnology surfaces are discussed.
The paper of USPolyResearch scientists proposing a novel interdisciplinary approach to revitalizing hot deserts is published in Advances in Space Research, world's leading space technology scholarly journal [Polyakov Y. S., Musaev I., and Polyakov S. V., "Closed Bioregenerative
Life Support Systems: Applicability to Hot Deserts", Advances in Space Research, 2010].
Latest results in flicker-noise spectroscopy, a phenomenological approach to the analysis of natural time and space series developed by USPolyResearch scientists, are published in Physical Review E, one of the most prestigious physical journals in the world [Timashev, S. F., Polyakov, Yu. S., Misurkin, P. I., and Lakeev, S. G., "Anomalous Diffusion as a Stochastic Component in the Dynamics of Complex Processes",
Physical Review E, 2010, Vol. 81, 041128.]
Conceptual summary of the paper: Random behavior in natural signals such as geoelectrical records in seismic areas and encephalograms may contain important information about the nature and evolution of the systems producing these signals. In this paper, it is shown that anomalous diffusion may be an essential mechanism accounting for the random variations in completely unrelated complex processes of different scales, ranging from blinking fluorescence of microscale quantum dots to X-ray emission produced by macroscale stellar objects. Anomalous diffusion is a generalization of Brownian motion characterized by a nonlinear dependence of the mean-square-displacement function on time. The signals were processed and the anomalous diffusion component extracted and parameterized by flicker noise spectroscopy, a toolset for analyzing arbitrary time series. The results of this study can be used to broaden the range of complex processes in which anomalous diffusion can be identified as an essential mechanism driving their random behavior. Of special importance for future research is the analysis of biomedical signals, such as encephalograms and magnetoencephalograms, because the degree of randomness in such signals is believed to be related to the health of human brain, which may be used in diagnosing neurodegenerative disorders.
USPolyResearch together with the Global Eco-Innovation Forum hosted an interdisciplinary conference "Sustainable Development of Hot Deserts" at Lerner Hall, Columbia University on October 31-November 1, 2009.
Drs. Serge Timashev and Yuriy Polyakov presented the latest research results on the analysis of biomedical signals in photodiagnosis at the 7th International Symposium in the field of Photodiagnosis and Photodynamics Therapy in South Tyrol, Italy. The presentation was titled
"Flicker-noise spectroscopy: analysis of biomedical signals in photodiagnosis".
Dr. Yuriy Polyakov made a key presentation at the seminar
called "Nonlinear dynamics of chemical reactions, processes, and reactors",
Chemistry Department of the Moscow State University, Moscow, Russia,
hosted by Prof. I.V. Melikhov, a corresponding member of the Russian Academy of Sciences, and
Prof. Yu.D. Tretyakov. a full member of the Russian Academy of Sciences.
The presentation, which was titled "Nonlinear Models of Mass Transfer in Pressure-Driven Processes",
discussed the class of nonlinear models dealing with various effects of nonuniform particle
deposition inside and outside the pores of semipermeable membranes.
To download the slides in PDF format, please click here.
Dr. Serge Timashev made an oral presentation at the 4th Symposium on
Fluctuations and Noise, Florence, Italy. The presentation, which was titled
"Phenomenological analysis of medical time series with regular and chaotic components",
discussed the application of Flicker-Noise Spectroscopy to the analysis of tremor velocity signals for Parkinsonian patients.
The paper published by Dr. Yuriy Polyakov ("Particle Deposition in
Outside-in Hollow Fiber Filters and Its Effect on Their Performance") in Journal of Membrane Science, 2006, Vol. 278, pp. 190-198
was recognized by the membranologists' community as a new research trend in membrane technology (Membrane Technology, 2007, Issue 1).
"New Scientist" magazine discusses the chaotic test developed in (Yulmetyev, R. M., Demin, S. A., Panischev, O. Yu., Hanggi, P., Timashev S.F., and
Vstovsky, G. V.,
"Regular and stochastic behavior of Parkinsonian pathological tremor signals", Physica A, 2006, Vol. 369, pp. 655-678).
For more information, please click here.
The study made by Dr. Yuriy Polyakov, "Design of Novel Energy-Saving Hollow-Fiber Membrane Filters for Recycling Water in Industrial Plants",
received the Moscow Mayor's Award for Outstanding Young Scientists.
For more information, please click here.
Dr. Yuriy Polyakov made an oral presentation at the 2005 Annual Meeting
of the North American Membrane Society, Providence, Rhode Island.
The presentation, which was titled "Beneficial Effect of Particle Adsorption
in UF/MF Outside-In Hollow Fiber Filters", discussed the synergetic
and complimentary combination of depth and membrane (micro- or ultra-) filtration in one filter.
To download the slides in PDF format, please click here.