Synthesis Of Micro Research Articles

The concept of identity: movement from the abstract to the concrete

The subject of the article is an overview of identitarian research results in Russia reflected in the cycle of the 2010-2023 fundamental scientific publications. The main result is the formation of an original Russian scientific school of identity studies and the establishment of this scientific area as an autonomous subdiscipline of political science. Two substantive dimensions of identitarian studies are identified - analytical-conceptual and substantive-political. Within the framework of the first one, the author analysesthe key theoretical parameters of identity studies, including the substantive evolution of the identity concept, theoretical and methodological context and semantic explications of identity studies. A number of identity theoretical articulations are considered: identity modus operandi (positive, negative), identity crises, development, complex society, political space and political time, social justice, social solidarity, civilisational and geopolitical identity, memory and culture wars, cancellation culture, cultural security and cultural sovereignty, and others. An overview of prospective identity studies is presented, including the synthesis of micro- and macro-level identity analyses; the development of the middle-level theories as the way to bridge the gap between empirical analysis and “big theory” in understanding the changes taking place in different regions of the world, taking into account the historical past, political culture, emotional structure and worldview; the relationship between macro-political identities and ideologies; the correlation between civic and ethnic identities; and the relationship between identity and ideology. The political significance of identity research reflects the need to reorient the contemporary way of thinking as predominantly consumerist to the responsible development imperatives, which is supported by a positive identity.

Insight into heating method and Mozafari method as green processing techniques for the synthesis of micro- and nano-drug carriers

Abstract Drug delivery systems, also known as bioactive carriers, are currently an important contribution to the pharmaceutical and biomedical industries. A leading category of these drug carriers is lipid- and phospholipid-based systems including liposomes, nanoliposomes, solid lipid nanoparticles, nanostructured lipid vesicles, archaeosomes, and tocosomes. At present, there are several methods available for the preparation of the lipidic drug carriers at the micro- and nanoscales. There are some misunderstandings and confusion in the literature regarding two of the scalable and environment-friendly (green) techniques developed in our laboratory, namely the heating method and the Mozafari method. These methods are superior to conventional procedures used in the synthesis of drug carriers due to the fact that they do not involve utilization of potentially toxic solvents, detergents, or high-shear homogenizations. This entry is aimed to clarify differences between these methods to the peers and colleagues in academia as well as relevant industries. Some details of the industrially applied patented instrument used in the manufacturing of lipidic carriers are also provided.

Shape-controlled synthesis of micro-/nanosized Cu particles with spherical and polyhedral shapes using the polyol process.

This study reports the synthesis of Cu micro-/nanosized particles through the polyol process. Cu particles were synthesized by reducing copper(ii) chloride in ethylene glycol (EG), polyvinylpyrrolidone (PVP), and potassium bromide (KBr) at low temperatures with or without the use of sodium borohydride (NaBH4).

Electrophoretic propulsion of matchstick-shaped magnetodielectric particles in the presence of external magnetic fields in a nematic liquid crystal.

Synthesis of micro- and nanoparticles of pre-designed shape and surface properties is an integral part of soft and synthetic active matter. We report synthesis of matchstick-shaped (MS) magnetodielectric particles and demonstrate their potential as active agents with field-controllable trajectories in a nematic liquid crystal (NLC). The MS particles with homeotropic anchoring in NLCs align either parallel or perpendicular to the director depending on the dipolar or quadrupolar director distortions. When subjected to transverse electric and magnetic fields, the particles experience electric and magnetic torques trying to align them in the respective field directions. At equilibrium, the long axis is tilted at an angle with respect to the director. The change in orientation alters the surrounding elastic distortion, which results in unbalanced electroosmotic flows. These flows provide the necessary impetus for propelling the particles in various directions with different velocities depending on their orientations.

Synthesis of micro- and nano-sized zinc sulfide crystallites by the method of self-propagating high-temperature synthesis

The paper presents the results that demonstrate how ZnS crystallites of different sizes can be obtained by the method of self-propagating high-temperature synthesis (SHS). The SHS is possible due to an exothermic reactions occurring in mixtures of Zn and S powders, due to a large amount of heat released (enthalpy of formation being 202 kJ/mol). Pressed powders of Zn and S are placed in a stoichiometric ratio into a reactor filled with Ar or N under a pressure of P>0.5 MPa. After initiated by ignition, the chemical reaction propagates through the mixture to produce a sample in the form of an ingot. ZnS crystallites with a characteristic size of ~ 30 μm are obtained in the traditional solid-state reaction of the SHS. Аfter the passage of the combustion wave, the reaction of the components continues in parallel with crystallization processes, which causes the formation of an active medium where self-organization processes occur. Sometimes, abnormally large ("giant") crystallites with length ~ 1 mm, thickness 0.1-0.2 mm, and regularly-shaped spatial structures are observed. The size of synthesized zinc sulfide crystallites can be changed with a dispersant, NH4Cl. When 5 wt.% of the dispersant is introduced, the monolithic sample is polycrystalline ZnS with a characteristic grain size of ~ 40 μm, and when 7 wt.% is introduced, the grain size decreases to 20 μm. As the concentration of the dispersant is increased to 10 wt. %, the synthesized material becomes loose, the characteristic grain size decreasing to 5-10 μm. At concentrations greater than 10 wt. %, powder-like ZnS is formed. The SHS method makes it possible to obtain meso- and nano-sized ZnS, with grain sizes of order 50 – 100 nm and 2 – 50 nm, respectively, in two ways. The first one consists in the condensation of the substance’s vapor in a rarefied inert atmosphere. When, during the SPS, the pressure of the inert gas changes in the interval from 40 to 400 Pa, a part of the reactants in the form of steam escapes from the ampoule into the reactor bulk. When the steam particles collide with the inert gas atoms, they quickly lose their kinetic energy to form particles with sizes of 2 to 100 nm. To form particles of the required size, it is necessary to adjust the pressure of the inert gas in the reactor. The second method for obtaining nanoparticles by the SBC is based on the use of an inert diluent, which prevents the growth of the forming particles. The main requirement for the diluent material is its inertness to both the reagents in the charge and the synthesized material. The effect of changing the pressure of the inert gas on the size of the obtained nanoparticles manifests itself both directly and indirectly—through the size of the condensation zone. As the gas pressure increases, its density increases, heat removal increases, the rate of crystallization center formation in the gas phase decreases, but the rate of crystal growth increases. As a result, so does the size of the resulting particles. The shape of nanoparticles obtained by this method depends on their size. Nanoparticles of size <20 nm have a shape close to spherical, which is a result changing the relative fraction of the surface energy in the total energy of a nanoparticle as its size decreases. Larger-size particles are faceted.

A Simple Method to Measure the Contact Angle of Metal Droplets on Graphite

The determination of solid–liquid interfacial tension plays an important role in science and technology. Here, we propose a simple method to directly measure the contact angle between metal droplets and a graphite substrate for the determination of metal–graphite interfacial tension. The proposed method involves the synthesis of micro- and nanosized metal droplets on graphite by arc melting. Owing to its small volume, the rapid cooling of the prepared metal droplets on the graphite substrate leads to the freezing of equilibrium contact configuration after solidification. We observe that the measured contact angle between micro- and nanosized Au (or Ag) particles and the graphite substrate is almost size independent, even though the size of the particles synthesized herein is 1–3 orders of magnitude smaller than that studied in previous works. In addition, the interfacial tensions of Au and Ag on the step edges (edge plane) of graphite are found to be larger than that on the (0001) plane (basal plane). The proposed method provides a simple approach to determine the solid–liquid interfacial tension and may be effective in the study of interface related science and technology.

Plasma-Chemical Facility for Synthesis of Micro- and Nanoparticles Having Controlled Compositions and Structures on the Basis of a Microwave Discharge in the Gyrotron Radiation

Plasma-Chemical Facility for Synthesis of Micro- and Nanoparticles Having Controlled Compositions and Structures on the Basis of a Microwave Discharge in the Gyrotron Radiation

Synthesis of micro and nanoparticles from pickling effluents from the hot-dip galvanizing industry

El proceso de galvanizado en caliente es una de las técnicas de protección contra la corrosión del acero más utilizadas y consiste en la inmersión del acero en un baño de zinc fundido. Este proceso consta de varias etapas y cada una de ellas produce residuos sólidos o efluentes con contenido metálico, que deben ser tratados antes de ser dispuestos en los vertedores y alcantarillado público. Estos residuos son alrededor de 1 000 000 t/año a nivel mundial. La eliminación segura de éstos es de gran importancia para la protección del medio ambiente. La etapa más crítica de este proceso es el decapado, que genera efluentes muy complejos de tratar debido al carácter ácido y contenido metálico, pero son de interés para la obtención de materiales de valor agregado. En este artículo se obtienen micro y nanopartículas de hierro y zinc a partir de efluentes de decapado de la industria del galvanizado en caliente, utilizando cuatro rutas diferentes de síntesis química (co-precipitación y sol-gel), obteniéndose partículas con diferentes tamaños, morfologías y estructuras cristalinas.

Synthesis of Micro- and Mesoporous Carbon Foams with Nanodispersed Metals for Adsorption and Catalysis Applications

This work focuses on carbon foams, whose peculiarity is a predominant open macroporous cellular network that can be provided with tailored texture and morphology by the modification of the preparation process. The goal was to obtain macroporous carbonaceous structures capable of being activated by following a simple thermo-foaming procedure using a few reagents. With this purpose in mind, carbon foams with different textural properties were synthesized from sucrose using two foaming processes: at atmospheric pressure and in a pressurized reactor. Iron and silver nitrates added to sucrose gave rise, after carbonization, to materials with iron oxides and elemental silver particles nano-dispersed in the carbon matrix and promoted microporosity in both cases and mesoporosity in the case of iron nitrate. Iron nitrate also catalyzes the graphitization of the carbon material during carbonization. All these findings show the potential of sucrose thermo-foaming process as a viable and sustainable path to produce versatile carbon materials, capable of being used in various applications.

Traditional vs. Microfluidic Synthesis of ZnO Nanoparticles.

Microfluidics provides a precise synthesis of micro-/nanostructures for various applications, including bioengineering and medicine. In this review article, traditional and microfluidic synthesis methods of zinc oxide (ZnO) are compared concerning particle size distribution, morphology, applications, reaction parameters, used reagents, and microfluidic device materials. Challenges of traditional synthesis methods are reviewed in a manner where microfluidic approaches may overcome difficulties related to synthesis precision, bulk materials, and reproducibility.

Synthesis of Micro-/Nanohydroxyapatite Assisted by the Taylor-Couette Flow Reactor.

Hydroxyapatite (HAP) has received increasing attention as an essential chemical product with good biocompatibility and adsorption properties. Generally, amorphous calcium phosphate (ACP) was generated first in the reactor and transformed into HAP after a period of crystallization. In this work, a series of Taylor-Couette flow reactors with different inner diameters were designed to assist in synthesizing HAP micro-/nanocrystals. ACP was obtained in a Taylor-Couette flow reactor at Re = 247 and successfully transformed into needle-like HAP crystals with a length of about 200 nm and a uniform particle size distribution after crystallization transformation. The yield of a single reactor can reach 2.16 kg per day. The finite element analysis results and time-space diagram of flow pattern variation showed that the Taylor-Couette flow reactor could improve the mixing behavior and the flow field distribution. The Taylor-Couette flow reactor provides a valuable reference for synthesizing inorganic micro-/nanomaterials.

Synthesis of micro- and nanosheets of CrCl3-RuCl3 solid solution by chemical vapour transport.

Solid solutions of 2D transition metal trihalides are rapidly growing in interest for the search for new 2D materials with novel properties at nanoscale dimensions. In this regard, we present a synthesis method for the Cr1-xRuxCl3 solid solution and describe the behaviour of the unit cell parameters over the whole composition range, which in general follows Vegard's law in the range of a = 5.958(6)CrCl3 … 5.9731(5)RuCl3 Å, b = 10.3328(20)CrCl3 … 10.34606(21)RuCl3 Å, c = 6.110(5)CrCl3 … 6.0385(5)RuCl3 Å and β = 108.522(15)CrCl3 … 108.8314(14)RuCl3 °. The synthesized solid solution powder was subsequently used to deposit micro- and nanosheets directly on a substrate by applying chemical vapour transport in a temperature gradient of 575 °C → 525 °C for 2 h and 650 °C → 600 °C for 0.5 h as a bottom-up approach without the need for an external transport agent. The observed chromium chloride enrichment of the deposited crystals is predicted by thermodynamic simulation. The results allow for a nanostructure synthesis of this solid solution with a predictable composition down to about 30 nm in height and lateral size of several μm. When applying a quick consecutive delamination step, it is possible to obtain few- and monolayer structures, which could be used for further studies of downscaling effects for the CrCl3-RuCl3 solid solution. X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy were used to confirm the purity and quality of the synthesized crystals.

The Synthesis of Micro- and Mesoporous Carbon Composite Materials by the Alkaline Dehydrochlorination of Polyvinyl Chloride

The Synthesis of Micro- and Mesoporous Carbon Composite Materials by the Alkaline Dehydrochlorination of Polyvinyl Chloride

One-pot two-step synthesis of micro- and mesoporous organic fibrils for efficient pseudocapacitors

A porous polyimide with a hexaazatriphenylene triimide group is synthesized from two pre-assembled monomers. Its micro- and mesoporous architecture enables fast ion diffusion for an efficient energy storage material with a high charge capacity.

An asymmetric flow-focusing droplet generator promotes rapid mixing of reagents

Nowadays droplet microfluidics is widely used to perform high throughput assays and for the synthesis of micro- and nanoparticles. These applications usually require packaging several reagents into droplets and their mixing to start a biochemical reaction. For rapid mixing microfluidic devices usually require additional functional elements that make their designs more complex. Here we perform a series of 2D numerical simulations, followed by experimental studies, and introduce a novel asymmetric flow-focusing droplet generator, which enhances mixing during droplet formation due to a 2D or 3D asymmetric vortex, located in the droplet formation area of the microfluidic device. Our results suggest that 2D numerical simulations can be used for qualitative analysis of two-phase flows and droplet generation process in quasi-two-dimensional devices, while the relative simplicity of such simulations allows them to be easily applied to fairly complicated microfluidic geometries. Mixing inside droplets formed in the asymmetric generator occurs up to six times faster than in a conventional symmetric one. The best mixing efficiency is achieved in a specific range of droplet volumes, which can be changed by scaling the geometry of the device. Thus, the droplet generator suggested here can significantly simplify designs of microfluidic devices because it enables both the droplet formation and fast mixing of the reagents within droplets. Moreover, it can be used to precisely estimate reaction kinetics.

Discovering Relationships between OSDAs and Zeolites through Data Mining and Generative Neural Networks.

Organic structure directing agents (OSDAs) play a crucial role in the synthesis of micro- and mesoporous materials especially in the case of zeolites. Despite the wide use of OSDAs, their interaction with zeolite frameworks is poorly understood, with researchers relying on synthesis heuristics or computationally expensive techniques to predict whether an organic molecule can act as an OSDA for a certain zeolite. In this paper, we undertake a data-driven approach to unearth generalized OSDA–zeolite relationships using a comprehensive database comprising of 5,663 synthesis routes for porous materials. To generate this comprehensive database, we use natural language processing and text mining techniques to extract OSDAs, zeolite phases, and gel chemistry from the scientific literature published between 1966 and 2020. Through structural featurization of the OSDAs using weighted holistic invariant molecular (WHIM) descriptors, we relate OSDAs described in the literature to different types of cage-based, small-pore zeolites. Lastly, we adapt a generative neural network capable of suggesting new molecules as potential OSDAs for a given zeolite structure and gel chemistry. We apply this model to CHA and SFW zeolites generating several alternative OSDA candidates to those currently used in practice. These molecules are further vetted with molecular mechanics simulations to show the model generates physically meaningful predictions. Our model can automatically explore the OSDA space, reducing the amount of simulation or experimentation needed to find new OSDA candidates.

Low-Temperature Synthesis of Micro–Mesoporous TiO2–SiO2 Composite Film Containing Fe–N Co-Doped Anatase Nanocrystals for Photocatalytic NO Removal

A simple low-temperature (< 100 °C) hot-water treatment was used to synthesize Fe–N co-doped anatase nanocrystals which were uniformly dispersed in micro–mesoporous SiO2 host film for the first time. The Fe–N co-doped TiO2–SiO2 (FNTS) film exhibited stable photocatalytic activities. A NO removal efficiency of 56.1% was achieved under simulated solar light irradiation without any obvious inactivation in 30 min. The transient photocurrent response of FNTS film is approximately six times higher than that of non-doped TiO2–SiO2 film, indicating the superior charge separation of photo-generated electron–hole pairs. Electron spin resonance analysis showed that the ·OH and ·O2− radicals were key species to remove NO. Combined with quantitative reaction intermediates, the possible photocatalytic degradation mechanism of NO over FNTS film was proposed. In addition, the FNTS thin films exhibited intrinsic super-hydrophilicity and durable self-cleaning property even after 6 months of storage in the dark. This work provides a facile method to load the catalyst on thermal labile substrates, such as soda–lime glass and organic polymer for more practical applications. A simple low-temperature (< 100 °C) hot-water treatment was used to synthesize micro–mesoporous TiO2–SiO2 composite film, which shows good self-cleaning ability and superior photodegradation activity for NO removal under solar light.

How Many Paradigms There are in Economic Theory – and Can it Become a One-paradigm Science

Over the past 100 years, economics has stood out from other scientific disciplines because of the presence of two fundamentally different approaches to understanding its subject: from a systemic point of view, and from the point of view of individual choice. All the main directions of modern economic theory turn out to be reducible to two paradigms, conceptually related to two main interpretations of the economic science subject. The understanding of the economy as an equilibrium or non-equilibrium system is associated with two said paradigms. The author believes that the development of economic theory after Keynes can be interpreted as a series of attempts to integrate the identified paradigms. In another form, this is the question of the synthesis of micro- and macro-approaches in economic theory.

Sensor Micro and Nanoparticles for Microfluidic Application

Micro and nanoparticles are not only understood as components of materials but as small functional units too. Particles can be designed for the primary transduction of physical and chemical signals and, therefore, become a valuable component in sensing systems. Due to their small size, they are particularly interesting for sensing in microfluidic systems, in microarray arrangements and in miniaturized biotechnological systems and microreactors, in general. Here, an overview of the recent development in the preparation of micro and nanoparticles for sensing purposes in microfluidics and application of particles in various microfluidic devices is presented. The concept of sensor particles is particularly useful for combining a direct contact between cells, biomolecules and media with a contactless optical readout. In addition to the construction and synthesis of micro and nanoparticles with transducer functions, examples of chemical and biological applications are reported.

Synthesis of micro- and nanostructured materials via oscillating reactions initiated by high-power microwave pulses

Herein we describe the results of our study of plasma chemical process initiated by high-power microwave pulses generated by 75/0.8 gyrotron (frequency 75 GHz, pulse duration up to 12 ms, power up to 550 kW) in mixtures of metal (Mg, Ti, Mo) and dielectric (Al2O3, AlN, B) powders. The process leads to formation of micro- and nanostructured materials and the yield is strongly affected by hydrogen-containing additives (C2B10H12, H3BO3, NaBH4) in the mixture. It was found that the process occurs in three main stages. The first initiation stage is very short (just slightly exceeds the pulse duration) and includes the absorption of microwave irradiation and the discharge proceeded as coulombic explosion. The main stage is much longer and includes decomposition of starting materials and reactions between all the components. All the tested additives prolong the main stage, in some cases by an order of magnitude or even more, and turn it into self-sustaining oscillating mode. The last one is realized most likely due to autothermic effect. As a result, the yield increases sufficiently. Finally, the decay stage is relatively short stage (up to 200 ms) following the main stage and includes irreversible cooling down of the reaction zone and deposition of the particles. The decay stage is not affected by additives. Owing to use the additives we were able to decrease the energy consumption for preparation of the materials below 1 kJ/g, which is 2–3 times lower compared to our previous results. The prepared materials were characterized by SEM, EDS and X-ray diffraction analysis and found to be mainly oxides, nitrides and borides.