ISOMORPHIC SIGNAL ENSEMBLES AND THEIR APPLICATION IN ASYNC-ADDRESS SYSTEMS

The object of consideration is async-address systems using code division of subscribers. The subject of the analysis is quasi-orthogonal ensembles of signals based on code sequences that have normalized characteristics of cross-correlation functions (CCF) and provide reliable separation of subscribers (objects) when exposed to imitation and signal-like interference. The purpose of the analysis is to create a model and methodology for construction a set of the best code sequences ensembles having the ability to quickly change the instance of the set to counter imitation and signal-like interference. The solution is based on algebraic models of code sequences and their CCF representation. The article proposes a comprehensive technique to construct signal ensembles set having normalized characteristics of the CCF. The quality of the primary ensemble of code sequences is ensured by the procedure for calculating the CCF optimized in the number of look over options. Optimization is based on the basic properties of the Galois field, in particular, on the Galois fields’ isomorphism property. It provides a significant reduction in calculations when choosing the primary ensemble of code sequences with the specified properties of the CCF. The very choice of the best (largest in size) code sequences ensemble relies on the solution of one of the classical combinatorics problems – searching for maximal clique on a graph. The construction of signals ensembles set having normalized characteristics of the CCF is ensured by the use of special combinatorial procedures and algorithms based on the multiplicative properties of Galois fields. An analysis of the effectiveness of known and proven procedures searching for maximal clique is also performed in this article. The work results will be useful in the design of infocommunication systems using complex signals with a large base and variable structure to provide protection from signal structure research and the effects of imitation and signal-like interferenc

An Interdisciplinary Approach to Predicting the Effects of Transboundary Atmospheric Transport to Northwest European Neighboring States

The Kola North is the most industrial territory of the Arctic region, where enterprises are sources of sulfur dioxide (SO2), which disperses widely not only throughout the Kola North, but also to the territories of neighboring Northwest European countries: Norway and Finland. The purpose of this study was to reveal the main sources of atmospheric SO2 pollution in the Kola North, assess the possible contribution of SO2 to the morbidity of respiratory diseases among children in the region, study the daily dynamics of SO2 content, and examine the likelihood of transboundary transport to neighboring states. The pathways of SO2 transfer throughout 2020 were revealed by using daily data about SO2 surface mass, wind direction and speed selected from the Geographic Information System for the cities of Zapolyarny (69∘24′55″ N, 30∘48′48″ E) and Olenegorsk (68∘08′35″ N, 33∘ 15′10″ E). It was found that the prevalence of pneumonia in 0-14-year-old children was associated with Olenegorsk, where the maximum of SO2 emissions was detected. The median values of SO2 surface mass were 2.7 times higher for Olenegorsk than for Zapolyarny and exceeded the maximum permissible concentration. The probability of SO2 transport to the territories of Norway and Finland was also estimated. This study highlights the complexity of the problem of transboundary airborne pollution transport, which requires interdisciplinary research to predict the consequences of the contamination for territories of the neighboring Northwest European countries. Keywords: Kola North, sulfur dioxide, respiratory morbidity among children, transboundary atmospheric transport, neighboring state

Pristupi socijalnim inovacijama za potporu integraciji migranata izvan EU-a u ruralnoj srednjoj Europi: stečena iskustva i doneseni zaključci

In recent years, many rural regions of Central Europe have witnessed a massive inflow of non-EU nationals, turning them into new migration destinations (NDMs). The majority of these regions were not prepared for this change and international migration became a hot-button topic. However, as the negative consequences of demographic change are getting more prominent in rural Central Europe, these regions should search for new ways to stimulate the integration of newly-arrived migrants. This can be done with the help of “social innovations.” This paper provides a literature overview on the aforementioned topics, as well as an analysis of the results of the Arrival Regions Project (Interreg CENTRAL EUROPE) that tested nine different social innovation approaches to support the integration of non-EU nationals in rural Central Europe. The results of the project confirmed that social innovation approaches are an effective and easy-toimplement way to support integration of non-EU nationals living in rural Central Europe.Posljednjih godina mnoge ruralne regije Srednje Europe svjedoče velikom priljevu državljana trećih zemalja, čime se pretvaraju u nova migracijska odredišta. Većina tih regija nije bila spremna za ovu promjenu, a međunarodne migracije postale su vruća tema. Međutim, kako su negativne posljedice demografskih promjena sve izraženije u srednjoeuropskim ruralnim područjima, te bi regije trebale tražiti nove načine za poticanje integracije novopridošlih migranata. To se može učiniti uz pomoć „društvenih inovacija”. Ovaj rad pruža pregled literature o spomenutim temama te analizu rezultata projekta Arrival Regions (Interreg CENTRAL EUROPE) kojim je testirano devet različitih pristupa socijalnim inovacijama za podršku integraciji državljana trećih zemalja u ruralnim područjima Srednje Europe. Rezultati projekta potvrdili su da su pristupi socijalnim inovacijama učinkovit i za provedbu jednostavan način potpore integraciji državljana trećih zemalja koji žive u ruralnim područjima Srednje Europe

Thin film Gallium nitride (GaN) based acoustofluidic Tweezer: Modelling and microparticle manipulation.

Gallium nitride (GaN) is a compound semiconductor which shows advantages in new functionalities and applications due to its piezoelectric, optoelectronic, and piezo-resistive properties. This study develops a thin film GaN-based acoustic tweezer (GaNAT) using surface acoustic waves (SAWs) and demonstrates its acoustofluidic ability to pattern and manipulate microparticles. Although the piezoelectric performance of the GaNAT is compromised compared with conventional lithium niobate-based SAW devices, the inherited properties of GaN allow higher input powers and superior thermal stability. This study shows for the first time that thin film GaN is suitable for the fabrication of the acoustofluidic devices to manipulate microparticles with excellent performance. Numerical modelling of the acoustic pressure fields and the trajectories of mixtures of microparticles driven by the GaNAT was performed and the results were verified from the experimental studies using samples of polystyrene microspheres. The work has proved the robustness of thin film GaN as a candidate material to develop high-power acoustic tweezers, with the potential of monolithical integration with electronics to offer diverse microsystem applications.Engineering and Physical Sciences Research Council Grant numbers: EP/P002803/1, EP/P018998/1, Natural Science Basic Research Program of Shaanxi Province/2020JQ-233, Fundamental Scientific Research of Central Universities/3102017OQD116, Engineering and Physical Sciences Research Council fellowship /EP/N01202X/2, Royal Society / IEC/NSFC/170142, IE161019, Natural Science Foundation of China/61704017, Dalian Science and Technology Innovation Fund/2018J11CY00

Power-controlled acoustofluidic manipulation of microparticles

Recently, surface acoustic wave (SAW) based acoustofluidic separation of microparticles and cells has attracted increasing interest due to accuracy and biocompatibility. Precise control of the input power of acoustofluidic devices is essential for generating optimum acoustic radiation force to manipulate microparticles given their various parameters including size, density, compressibility, and moving velocity. In this work, an acoustophoretic system is developed by employing SAW based interdigital electrode devices. Power meters are applied to closely monitor the incident and reflected powers of the SAW device, which are associated with the separation efficiency. There exists a range of input powers to migrate the microparticles to the pressure node due to their random locations when entering the SAW field. Theoretical analysis is performed to predict a proper input power to separate mixtures of polystyrene microspheres, and the end lateral position of microspheres being acoustically separated. The separation efficiency of four sizes of microspheres, including 20 µm, 15 µm, 10 µm, and 5 µm, is calculated and compared with experimental results, which suggest the input power for separating the mixture of these microspheres. The study provides a practical guidance on operating SAW devices for bioparticle separation using the incident power as a control parameter

A Reconfigurable and Portable Acoustofluidic System Based on Flexible Printed Circuit Board for the Manipulation of Microspheres

Acoustofluidic devices based on surface acoustic waves (SAWs) have been widely applied in biomedical research for the manipulation and separation of cells. In this work, we develop an accessible manufacturing process to fabricate an acoustofluidic device consisting of a SAW interdigital transducer (IDT) and a polydimethylsiloxane (PDMS) microchannel. The IDT is manufactured using a flexible printed circuit board (FPCB) pre-patterned with interdigital electrodes (IDEs) that is mechanically coupled with a piezoelectric substrate. A new microchannel moulding technique is realised by 3D printing on glass slides and is demonstrated by constructing the microchannel for the acoustofluidic device. The flexible clamping mechanism, used to construct the device, allows the reconfigurable binding between the IDT and the microchannel. This unique construction makes the acoustofluidic device capable of adjusting the angle between the microchannel and the SAW propagation, without refabrication, via either rotating the IDT or the microchannel. The angle adjustment is demonstrated by setting the polystyrene microsphere aggregation angle to -5°, 0°, 6°, and 15°. Acoustic energy density measurements demonstrate the velocity of microsphere aggregation in the device can be accurately controlled by the input power. The manufacturing process has the advantages of reconfigurability and rapid-prototyping to facilitate preparing acoustofluidic devices for wider applications

Dual-Wave Acoustofluidic Centrifuge for Ultrafast Concentration of Nanoparticles and Extracellular Vesicles

Extracellular vesicles (EVs) are secreted nanostructures that play various roles in critical cancer processes. They operate as an intercellular communication system, transferring complex sets of biomolecules from cell to cell. The concentration of EVs is difficult to decipher, and there is an unmet technological need for improved (faster, simpler, and gentler) approaches to isolate EVs from complex matrices. Herein, an acoustofluidic concentration of extracellular vesicles (ACEV) is presented, based on a thin-film printed circuit board with interdigital electrodes mounted on a piezoelectric substrate. An angle of 120° is identified between the electrodes and the reference flat of the piezoelectric substrate for simultaneous generation of Rayleigh and shear horizontal waves. The dual waves create a complex acoustic field in a droplet, resulting in effective concentration of nanoparticles and EVs. The ACEV is able to concentrate 20 nm nanospheres within 105 s and four EV dilutions derived from the human prostate cancer (Du145) cell line in approximately 30 s. Cryo-electron microscopy confirmed the preservation of EV integrity. The ACEV device holds great potential to revolutionize investigations of EVs. Its faster, simpler, and gentler approach to EV isolation and concentration can save time and effort in phenotypic and functional studies of EVs

Thin film Gallium nitride (GaN) based acoustofluidic Tweezer: Modelling and microparticle manipulation

Gallium nitride (GaN) is a compound semiconductor which shows advantages in new functionalities and applications due to its piezoelectric, optoelectronic, and piezo-resistive properties. This study develops a thin film GaN-based acoustic tweezer (GaNAT) using surface acoustic waves (SAWs) and demonstrates its acoustofluidic ability to pattern and manipulate microparticles. Although the piezoelectric performance of the GaNAT is compromised compared with conventional lithium niobate-based SAW devices, the inherited properties of GaN allow higher input powers and superior thermal stability. This study shows for the first time that thin film GaN is suitable for the fabrication of the acoustofluidic devices to manipulate microparticles with excellent performance. Numerical modelling of the acoustic pressure fields and the trajectories of mixtures of microparticles driven by the GaNAT was performed and the results were verified from the experimental studies using samples of polystyrene microspheres. The work has proved the robustness of thin film GaN as a candidate material to develop high-power acoustic tweezers, with the potential of monolithical integration with electronics to offer diverse microsystem applications