137 research outputs found
Millicharged neutrino with anomalous magnetic moment in rotating magnetized matter
New exact solutions of the modified Dirac equation describing a neutrino with
nontrivial electromagnetic properties in extreme background conditions are
obtained. Within the quasi-classical treatment the effective Lorentz force that
describes the neutrino propagation in the magnetized rotating matter is
introduced. We predict the effect of the spatial separation of different types
of relativistic neutrinos and antineutrinos (different in flavors and energies)
by the magnetized rotating matter of a star. Low energy neutrinos can be even
trapped inside the star. We also predict two new phenomena: a new type of the
neutrino electromagnetic radiation (termed "Light of (milli)Charged Neutrino",
) and a new mechanism of the star angular velocity shift due to
neutrinos escaping the star (termed "Neutrino Star Turning" mechanism, ). The possible impact of the mechanism on a supernova explosion
yields a new astrophysical limit on the neutrino millicharge
. In addition, the mechanism can be
also used to explain the origin of pulsar "anti-glitches" and ordinary glitches
as well.Comment: 18 pages, minor typos corrected and several references adde
PROBING AND CONTROLLING FLUID RHEOLOGY AT MICROSCALE WITH MAGNETIC NANORODS
This Dissertation is focused on the development of new methods for characterization and control of fluid rheology using magnetic nanorods. This Dissertation consists of five chapters. In the first chapter, we review current microrheologial methods and develop a Magnetic Rotational Spectroscopy (MRS) model describing nanorod response to a rotating magnetic field. Using numerical modeling, we analyze the effects of materials parameters of nanorods and fluids on the MRS characteristic features. The model is designed for a specific experimental protocol. We introduce and examine physical parameters which can be measured experimentally. The model allows identification of MRS features enabling the calculation of fluid viscosity. The MRS of Non-Newtonian fluids with exponentially increasing viscosity is discussed for the first time. In the second chapter, we review the techniques for magnetic nanorods synthesis. We describe a setup and experimental protocol to synthesize nickel nanorods with the desired geometrical properties, in particular, with the controlled length to diameter ratio. We review magnetic systems used for manipulation of magnetic nanoparticles. A multifunctional magnetic rotator is introduced and described in detail in this chapter. We believe that this multifunctional magnetic system will be useful not only for micro and nanorheological studies, but will find much broader applications requiring remotely controlled manipulation of micro and nanoobjects. In the third chapter, we describe the MRS experiments and use the model developed in the first chapter for characterization of magnetic properties of synthesized nickel nanorods. The same setup is used to measure viscosity of microdroplets. We show that the diffraction pattern from the suspension of nickel nanorods aligned in a magnetic field can be rotated by a spinning magnetic field. This effect opens up an opportunity for the MRS using much smaller nanorods. Another practical application of the controlled diffraction patterns is discussed: the use of this pattern in medical optofluidic devices producing stationary illuminating spots, for example, in endoscopes. In the fourth chapter, we report on a new MRS method which can be used for the in-situ (or in-vivo) rheological measurements of fluids and polymer systems when the fluid viscosity increases exponentially with time. We use this method to measure the exponential change of the viscosity of HEMA (2-hydroxyethyl-methacrylate) undergoing photopolymerization. Remarkably, an exponential increase of viscosity can be traced beyond the point when the polymer system undergoes transition to a gel and the gel domains start to appear. We expect that this method will open up new horizons in the quantitative rheological analysis of fluids inside living cells, microorganisms, and aerosol droplets with thickeners. In the fifth chapter, we describe a physical principle of self-assembly of magnetic nanorods into droplets of different sizes. These droplets can be formed on demand using magneto-static interactions between magnetic nanorods and a magnetic field gradient. We theoretically and experimentally confirmed that the cluster of nanorods at the top of the droplet is acting as a cone-shape solid body deforming the top part of the droplet when moving towards the magnet. The developed model allows one to selectively concentrate a finite amount of magnetic nanorods at the free surface and print multiple microdroplets on demand
Π§ΡΠΎ Π΄Π΅Π»Π°ΡΡ Π°ΡΡ ΠΈΡΠ΅ΠΊΡΠΎΡΡ Ρ ΠΈΡΡΠΎΡΠΈΠ΅ΠΉ Π°ΡΡ ΠΈΡΠ΅ΠΊΡΡΡΡ?
The article considers the aspects of teaching of history and theory of architecture and the relations between humanity and design subjects. The touch point of design and history may consist in consideration of the tasks, which have been facing the architecture throughout its history, and their solutions. The educational result of the course should be not only studentsβ historical knowledge, but also their ability to analyze projects regardless of the time of their construction.ΠΡΠ±Π»ΠΈΠΊΠ°ΡΠΈΡ ΠΏΠΎΡΠ²ΡΡΠ΅Π½Π° ΠΏΡΠ΅ΠΏΠΎΠ΄Π°Π²Π°Π½ΠΈΡ ΠΈΡΡΠΎΡΠΈΠΈ ΠΈ ΡΠ΅ΠΎΡΠΈΠΈ Π°ΡΡ
ΠΈΡΠ΅ΠΊΡΡΡΡ ΠΈ Π²Π·Π°ΠΈΠΌΠΎΠΎΡΠ½ΠΎΡΠ΅Π½ΠΈΡΠΌ Π³ΡΠΌΠ°Π½ΠΈΡΠ°ΡΠ½ΡΡ
ΠΏΡΠ΅Π΄ΠΌΠ΅ΡΠΎΠ² Ρ ΠΏΡΠΎΠ΅ΠΊΡΠ½ΡΠΌΠΈ Π΄ΠΈΡΡΠΈΠΏΠ»ΠΈΠ½Π°ΠΌΠΈ. Π’ΠΎΡΠΊΠΎΠΉ ΡΠΎΠΏΡΠΈΠΊΠΎΡΠ½ΠΎΠ²Π΅Π½ΠΈΡ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΈ ΠΈΡΡΠΎΡΠΈΠΈ ΠΌΠΎΠΆΠ΅Ρ ΡΡΠ°ΡΡ ΠΎΠ±ΡΡΠΆΠ΄Π΅Π½ΠΈΠ΅ Π·Π°Π΄Π°Ρ, ΡΡΠΎΡΡΠΈΡ
ΠΏΠ΅ΡΠ΅Π΄ Π°ΡΡ
ΠΈΡΠ΅ΠΊΡΡΡΠΎΠΉ Π½Π° ΠΏΡΠΎΡΡΠΆΠ΅Π½ΠΈΠΈ Π΅Π΅ ΠΈΡΡΠΎΡΠΈΠΈ ΠΈ ΡΠΏΠΎΡΠΎΠ±ΠΎΠ² ΠΈΡ
ΡΠ΅ΡΠ΅Π½ΠΈΡ. ΠΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΡΠΌ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠΌ ΠΊΡΡΡΠ° ΠΈΡΡΠΎΡΠΈΠΈ Π΄ΠΎΠ»ΠΆΠ½ΠΎ ΡΡΠ°ΡΡ Π½Π΅ ΠΏΡΠΎΡΡΠΎ Π·Π½Π°Π½ΠΈΠ΅ ΠΈΡΡΠΎΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Π°, Π½ΠΎ ΠΈ ΡΠΌΠ΅Π½ΠΈΠ΅ ΡΡΡΠ΄Π΅Π½ΡΠ° ΡΠ°ΠΌΠΎΡΡΠΎΡΡΠ΅Π»ΡΠ½ΠΎ Π°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°ΡΡ ΠΏΡΠΎΠ΅ΠΊΡΡ ΠΈ ΠΏΠΎΡΡΡΠΎΠΉΠΊΠΈ Π½Π΅Π·Π°Π²ΠΈΡΠΈΠΌΠΎ ΠΎΡ Π²ΡΠ΅ΠΌΠ΅Π½ΠΈ ΠΈΡ
Π²ΠΎΠ·Π²Π΅Π΄Π΅Π½ΠΈΡ
Permafrost hydrology in changing climatic conditions: seasonal variability of stable isotope composition in rivers in discontinuous permafrost
Role of changing climatic conditions on permafrost degradation and hydrology was investigated in the transition zone between the tundra and forest ecotones at the boundary of continuous and discontinuous permafrost of the lower Yenisei River. Three watersheds of various sizes were chosen to represent the characteristics of the regional landscape conditions. Samples of river flow, precipitation, snow cover, and permafrost ground ice were collected over the watersheds to determine isotopic composition of potential sources of water in a river flow over a two year period. Increases in air temperature over the last forty years have resulted in permafrost degradation and a decrease in the seasonal frost which is evident from soil temperature measurements, permafrost and active-layer monitoring, and analysis of satellite imagery. The lowering of the permafrost table has led to an increased storage capacity of permafrost affected soils and a higher contribution of ground water to river discharge during winter months. A progressive decrease in the thickness of the layer of seasonal freezing allows more water storage and pathways for water during the winter low period making winter discharge dependent on the timing and amount of late summer precipitation. There is a substantial seasonal variability of stable isotopic composition of river flow. Spring flooding corresponds to the isotopic composition of snow cover prior to the snowmelt. Isotopic composition of river flow during the summer period follows the variability of precipitation in smaller creeks, while the water flow of larger watersheds is influenced by the secondary evaporation of water temporarily stored in thermokarst lakes and bogs. Late summer precipitation determines the isotopic composition of texture ice within the active layer in tundra landscapes and the seasonal freezing layer in forested landscapes as well as the composition of the water flow during winter months
Crop leaves high-resolution images analysis and segmentation by a convolutional neural network under small sampling condition
The authors propose an algorithm for analysing and segmenting high-resolution images of cultivated plant leaves by a convolutional neural network of deep learning in conditions of small samples. The algorithm implemented in the hardware and software complex includes images preprocessing procedures with the elimination of distortions if they are present, data augmentation to increase the number of variations, classification of signs by textural characteristics in order to identify diseases with subsequent segmentation of images of affected leaves
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