Nikolai I Lebovka

Biocolloidal Chemistry Institute named after F. D. Ovcharenko, National Academy of Sciences of Ukraine

The modified model with repulsive filling ( CSA r ) for adsorption of monomers on a square lattice was studied. The deposition probability at empty sites P was regulated using the power law P = 1 − ( z / 4 ) α , where z is the number of NN sites filled by previously deposited particles and α ( > 0 ) is a parameter. The interval of α = 10 − 3 − 10 3...

The ageing processes in the systems of elongated particles (discorectangles) adsorbed on a plane was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was tested. The initial jammed state was produced using the random sequential adsorption (RSA) model. The transition from the jammed to equilib...

A quantum mechanical theory for description of electronic quasistationary states in two-dimensional (2D) layered semiconductor nanostructure was developed. A constant external magnetic field B was directed along semiconductor layers. The presence of internal electric fields F originated from the potential barriers and wells in semiconductor layers...

Проведено дослiдження адсорбцiї анiзометричних частинок (дископрямокутникiв) на двовимiрнiй площинi. Спiввiдношення сторiн (вiдношення довжини до ширини ɛ = l/d) змiнювали в iнтервалi ɛ = 1–10. Було вивчено модифiковану модель випадкової послiдовної адсорбцiї (RSA). У цiй моделi частинки були покритi оболонками, що вiдштовхуються. Основними парамет...

Connectedness percolation phenomena in the two-dimensional (2D) packing of binary mixtures of disks with different diameters were studied numerically. The packings were produced using random sequential adsorption (RSA) model with simultaneous deposition of disks. The ratio of the particle diameters was varied within the range D=1-10, and the select...

The phase diagrams for the light H2O, heavy D2O water, and inert substances (Ne, Ar, Kr, and Xe) have been compared. A method of choosing the starting point for entropy and internal energy was proposed. It allowed testing the principle of corresponding states using caloric variables. In the given coordinates of temperature, pressure, and chemical p...

The two-dimensional (2D) packings of binary mixtures of disks with diameter $d$ and discorectangles with aspect ratio $\varepsilon$ (length-to-width ratio $\varepsilon=l/d$) were studied numerically. The competitive random sequential adsorption (RSA) with simultaneous deposition of particles was considered. The aspect ratio was changed within the r...

We study saturated packings produced according to the random sequential adsorption (RSA) protocol built of identical rectangles deposited on a flat, continuous plane. An aspect ratio of rectangles is defined as the length-to-width ratio, f = l / w . The rectangles have a fixed unit area (i.e. l × w = 1 ), and therefore, their shape is defined by th...

The different variants of two-stage random sequential adsorption (RSA) models for packing of disks and discorectangles on a two-dimensional (2D) surface were investigated. In the SD (sticks+disks) model, the discorectangles were first deposited and then the disks were added. In the DS (disks+sticks) model, the disks were first deposited and then di...

The different variants of two-stage random sequential adsorption (RSA) models for packing of disks and discorectangles on a two-dimensional (2D) surface were investigated. In the SD model, the discorectangles were first deposited and then the disks were added. In the DS model, the disks were first deposited and then discorectangles were added. At t...

This review aims to provide a literature overview as well as the authors' personal account to the studies of Laponite® (Lap)/Polyethylene-oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico-chemica...

The non-isothermal adsorption/desorption of gas in a cylindrical column filled with adsorbent particles has been considered theoretically. The model is based on Langmuir theory for equilibrium adsorption. Using the Heaviside operational method the analytical solutions for kinetics of changes of concentration of adsorbate in the inter- and intra-par...

We study saturated packings produced according to random sequential adsorption (RSA) protocol built of identical rectangles deposited on a flat, continuous plane. An aspect ratio of rectangles is defined as the length-to-width ratio, $f=l/w$. The rectangles have a fixed unit area (i.e., $l \times w=1$), and therefore, their shape is defined by the...

The current state of the study of different liquid crystalline (LC) systems doped with carbon nanotubes (CNTs) is discussed. An attempt is endeavored to outline the state-of-the-art technology that has emerged after two past decades. Systematization and analysis are presented for the integration of single- and multi-walled carbon nanotubes in therm...

Hybrid magnetic particles based on Laponite® (Lap) (Rockwood Additives Ltd., UK) and nanomagnetic (NM) particles have been synthesized. The NM was synthesized using the Elmore method. For preparation of LapM hybrids, the Lap and NM were mixed in aqueous suspensions at pH 7.3 and T = 298 K. The concentration of NM particles at suspensions was fixed...

The freshwater microalga Haematococcus pluvialis is well known as the cell factory for natural astaxanthin, which composes up to 4–7% of its total dry weight. The bioaccumulation of astaxanthin in H. pluvialis cysts seems to be a very complex process that depends on different stress conditions during its cultivation. The red cysts of H. pluvialis d...

A two-dimensional Monte Carlo simulation of dead-end diafiltration of bidispersed particle suspensions was performed. The diafiltration process involves separation of components based on their size by using a permeable membrane. The continuous model was applied to study separation of mixture of disks with diameter d and D (D>d). It was assumed that...

In the last two decades, pulsed electric fields (PEF) have successfully been introduced into the food industry, as one of the most promising and "game changing" technologies. This review is devoted to the recent applications of pulsed electric fields used in processing potatoes. The potato processing market size was estimated to be ca. USD 24.83 bi...

Pulsed electric fields (PEFs) are becoming more and more popular in different applications in processing agricultural products. The PEF technology is based on the application of high voltage short pulses that allow electroporation in the cell membranes. This review outlines the PEF applications used in processing sugar beets. New perspective techno...

This book addresses new challenges in soft matter and colloids. It presents timely reports on colloidal self-assembly, soft matters from liquid crystals, nanoparticles in liquid crystals, hydrocolloids, hybrid nanosystems, nanosuspensions, and dispersion of nanoparticles in different media, soft matter processing and modern experiments related with...

The chapter presents a review on the history of the application of electricity in food processing. The early works before the middle of the twentieth century on the bactericidal and plasmolysis effects of electricity were shortly presented. Development of the concept of electroplasmolysis with a description of the activity of key persons (Anatolii...

The chapter reviews applications of pulsed electric fields (PEF) for the efficient extraction of intercellular components from food plants. Mechanisms of cell membrane permeabilization by PEF including electroporation of plane membranes, spherical cells, cells with different shapes and sizes, and ensembles of cells and plant tissues are discussed....

Relaxation of the packing of elongated particles (discorectangles) aligned on a line was studied numerically. The aspect ratio (length-to-width ratio) for the discorectangles was varied within the range ɛ∈[1;50]. The initial jamming (saturated) state was produced using the basic variant of the random sequential adsorption model with random position...

The behavior of a system of two-dimensional elongated particles (discorectangles) packed in a slit between the two parallel walls was analyzed using a simulation approach. The packings were produced using the random sequential adsorption model with continuous positional and orientational degrees of freedom. The aspect ratio (length-to-width ratio,...

Typically, the carrot tissues have rather high initial moisture content and low porosity. Expression of juice from such tissue may be rather complicated and include different stages. In this work, a simple creep tests with carrot tissue treated by pulsed electric fields (PEF) were performed. The samples were compressed for 15 min in a special jig u...

Relaxation of the packing of elongated particles (discorectangles) aligned on a line was studied numerically. The aspect ratio (length-to-width ratio) for the discorectangles was varied within the range $\varepsilon \in [1;50]$. The initial jamming (saturated) state was produced using the basic variant of the random sequential adsorption (RSA) mode...

Results of a comparative analysis of spectral-luminescent properties of crystalline and glassy benzophenone are presented. The main spectral characteristics (frequencies of purely electronic transitions in phosphorescence spectra, band half-widths, relative quantum yields) of glassy benzophenone have been found to possess a number of significant fe...

Hybrid magnetic particles based on Laponite® (Lap) can be promising agents for ecology, therapeutics and diagnostic purposes. These materials combine unique magnetic and surface properties (e.g., high surface area, easily adjustable surface charge, relatively high adsorption capacity etc.). Due to its magnetic properties the external magnetic field...

The behavior of a system of two-dimensional elongated particles (discorectangles) packed into a slit between two parallel walls was analyzed using a simulation approach. The packings were produced using the random sequential adsorption model with continuous positional and orientational degrees of freedom. The aspect ratio (length-to-width ratio, $\...

Recent studies of the nanoparticle self-assembling in liquid crystals (LCs) are reviewed. The data on investigations of phase transitions, optico-luminescent, electrophysical and other functional properties are presented. The considered nanoparticles include surface-functionalized single-and multi-walled carbon nanotubes (CNTs) [1], Laponite  (Lap...

Connectedness percolation phenomena in the two-dimensional packing of elongated particles (discorectangles) were studied numerically. The packings were produced using random sequential adsorption off-lattice models with preferential orientations of the particles along a given direction. The partial ordering was characterized by the order parameter...

Dead-end electro-filtration of polyphenols extracted from apple skin was studied. The influence of membrane pore size (dm=3.02-50 nm), transmembrane pressure (ΔP=1-6 bar) and direct current (DC) electric field (U=5-15 V) on the purification efficiency was investigated. The sieving ratios R of selected membrane UH030 (dm=4.35 nm) towards the polyphe...

The effects of pulsed electric field (PEF) treatment and preliminary vacuum drying (VD) on freezing assisted processes for the potato tissue were studied. The PEF treatment was done at 600 V/cm using the protocol to insure the high level of potato disintegration. The VD was done at sub-atmospheric pressure of p = 0.30 bar. Such conditions allowed r...

Recent applications of pulsed electric energy (PEE) for the processing of food and agricultural products are reviewed in this chapter. The historical background and electroporation fundamentals for different food materials are presented. The chapter includes information about PEE treatment protocols, equipment, and chambers, and presents the main m...

Connectedness percolation phenomena in two-dimensional packings of elongated particles (discorectangles) were studied numerically. The packings were produced using random sequential adsorption (RSA) off-lattice model with preferential orientations of particles along a given direction. The partial ordering was characterized by order parameter $S$, w...

This work discusses the synthesis and the properties of magnetite modified LAPONITE® RD platelets (Lap). Magnetized Lap (mLap) nanoparticles were synthesized by a co-precipitation method with different weight ratios, X = Fe3O4/Lap (0–2). For characterization of the samples the particle size distributions and sedimentation behavior in an external ma...

A computer simulation was used to study the random sequential adsorption of identical discorectangles onto a continuous plane. The problem was analyzed for a wide range of discorectangle aspect ratios ( ɛ ∈ [ 1 ; 100 ] ). We studied the anisotropic deposition, i.e., the orientations of the deposited particles were uniformly distributed within some...

The random sequential adsorption (RSA) of identical elongated particles (discorectangles) on a line (“Paris car parking problem”) was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The possible orientations of the discorectanles were restricted between θ∈[−θm;θm] while the...

Computer simulation was used to study the random sequential adsorption of identical discorectangles onto a continuous plane . The problem was analyzed for a wide range of discorectangle aspect ratios ($\varepsilon \in [1;100]$). We studied anisotropic deposition, i.e., the orientations of the deposited particles were uniformly distributed within so...

The random sequential adsorption (RSA) of identical elongated particles (discorectangles) on a line ("Paris car parking problem") was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The possible orientations of the discorectanles were restricted between $\theta \in [-\theta_\...

The aqueous suspensions of Laponite RD (Lap) platelets demonstrate rich phase diagrams. Both PEO and CTAB molecules competitively adsorb on the surface of Lap and strong interactions between PEO and CTAB exist. The stability of ternary systems Lap+PEO+CTAB can be finely regulated by changing the balance of these interactions. Electrokinetic techni...

Aqueous extraction assisted by pulsed electric energy (PEE) and ultrasonication (US) were tested for three microalgal species (Nannochloropsis sp., Phaeodactylum tricornutum, Parachlorella kessleri). The PEE treatments were applied using pulsed electrical fields (PEF) and high voltage electrical discharges (HVED) modes. The extraction degrees of ca...

In this study, the optimization of ultrasound‐assisted aqueous extraction of polyphenols from pomegranate peels and seeds was conducted. A 10‐min sonication (tu) pre‐treatment (≈60 W) accelerated the extraction kinetics and intensified the polyphenol recovery from peels and seeds. Ultrasound pre‐treatment permitted the selective recovery of polyphe...

This chapter shortly presents the concepts of pulsed electric energy (PEE) generators, treatment protocols and design of batch and continuous treatment chambers (nano- and micro-scale fluidic chips, small-scale cuvettes, laboratory, pilot and industrial scale chambers). The manufacturers of small scale electroporation devices and large scale PEE eq...

The grapes are cultivated all over the world and used as a fresh fruit and for the production of juice and wine. The grape berries are very rich in bioactive molecules such as carbohydrates, fruit acids, mineral elements, nitrogenous and aroma-producing compounds, vitamins, thiamine, riboflavin, anthocyanins responsible for the colour of red wine,...

Detection and quantifying of electroporation effects in food and biological materials (food plants, biomass feedstocks and bio-suspensions) is very important for numerous practical applications. Currently, different methods and techniques have been proposed to detect and measure electroporation effects. This chapter presents the current methods to...

Effects of electricity on biological objects attracted a great attention of researches over several centuries. Many interesting, intriguing, and unclear phenomena were discovered under application of electricity. The early works on the effects of electricity on germination, vegetation, plants growth, medical applications, and killing of bacteria we...

Drying is widely used for the dehydration of food plants (fruits, vegetables) and biomass feedstocks. Efficiency of drying depends on the processing conditions, structure of the material (size and orientation of cells, their integrity), and types of cellular water in the samples. Efficiency of the traditional convective air drying is rather low, th...

Cell membrane electroporation phenomena depend on the size of cells, their spatial orientation, electro-physical parameters of cells, pH of surrounding media and presence of osmotic agents. This chapter discusses fundamentals of membrane electroporation, various non-pore and pore models (condenser and conductor approximations), stages of electropor...

Freezing at subzero temperatures is widely used to preserve quality of food products and obtain minimal deterioration of original colour, flavour, texture and other organoleptic and nutritional properties of foods. Existing freezing preservation technique goals to avoid formation of large ice crystals inside the foods by control the heat removal. T...

Among conventional extraction techniques in food and biorefinery applications, solvent extraction (named leaching, diffusion) and expression (pressing) are the most important. Solid/liquid extraction and expression are widely used for the production of fruit juices, wines, sugar, vegetable oils and starch, as well as for the extraction of different...

The “fruit” means the fleshy seed-associated structures of a plant that are sweet or sour, and edible in the raw state. The systems for classifying of fruits are related to food composition and based on botanic families, colours, and edible parts of plants. This chapter discusses examples of application of the PEE for processing of three types of f...

Sugar crops include sugar beet, sugarcane, sweet sorghum, sugar maple, sugar palm, honey, corn, and chicory. Sugar is a broad term applied to a large number of carbohydrates that have a more or less sweet taste. Sugar crops are the basic feed stocks in the traditional converting technologies producing sugar, inulin and other food ingredients. The r...

Potato and carrot are important sources of energy (starch), high-quality proteins, fibers, and vitamins. This chapter considers examples of PEE application for the processing of potato and carrot crops. For potato, the applications of PEF for French fries manufacturing, improving of drying and extraction processes and treatment of peel wastes are p...

Biomass usually refers to the nonfood part of plants, by-products and wastes. Various biomass resources include wood wastes, grass and herbaceous crops, agricultural and industrial residues like bagasse, sugar beet pulp and molasses, oilseed residues, municipal solid wastes, aquatic plants, microalgae, animal wastes, etc. Dedicated feedstocks are t...

This book presents a comprehensive range of research on pulsed electric energy used in food processing, including sections on the fundamentals of electroporation and important techniques for the estimation of electroporation effects in various foods and biomass feedstocks. By focusing on application over theory, this book presents researchers with...

Two-step procedure with the initial aqueous extraction from raw microalgae Nannochloropsis oculata and secondary organic solvent extraction from vacuum dried (VD) microalgae were applied for selective recovery of bio-molecules. The effects of preliminary aqueous washing and high voltage electrical discharges (HVED, 40 kV/cm, 4 ms pulses) were teste...

The effects of physical treatments (pulsed electrical fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US)) on aqueous extraction of carbohydrates and proteins, and ethanolic extraction of chlorophyll a from three microalgal species (Nannochloropsis sp., P. tricornutum and P. kessleri) have been studied. The total energy...

The pulsed electric field (PEF) assisted extraction of bio-compounds (soluble solids concentration, oBrix, and total polyphenol content, TPC) from apple peels was studied. The aqueous suspensions of apple peels were treated by PEF with different intensities, E (480-1200 V/cm), and different treatment times, tPEF (0-2 s). The cell disintegration was...

A multi-step aqueous and non-aqueous extraction procedure was applied to recovery bio-molecules from Phaeodactylum tricornutum. The process include that physical pre-treatments (high voltage electrical discharges (HVED, 40 kV/cm, 1–8 ms, HVED samples) or high pressure homogenization (HPH, 1200 bar, 10 passes, P samples)) (1st step); aqueous extract...

This review analyses the authors’ recent and related works on electrokinetic properties and colloidal stability of aqueous suspension of multiwalled carbon nanotubes (CNTs) in the presence of surfactants and nanoparticles. Selected adsorptive properties of carbon nanotubes are also considered. The applicability of classical theories of electrophore...

Background Nowadays, electron spin resonance (ESR) is widely used as a powerful, non-destructive and very sensitive technique for the detection of free radicals in food systems. It can be applied for the direct identification of highly reactive oxygen species, organic and inorganic paramagnetic species and screening of food for potential toxicity....

Farming and production of food are one of the oldest industries in the human history. Among other issues, food processing is an important part in the whole food industry. It includes the methods and techniques used to transform raw material into food for human consumption. Most of these techniques are well known and their principals have not been c...

To be published as a chapter of Order, Disorder and Criticality. Advanced Problems of Phase Transition Theory, Volume 6. Edited By: Yurij Holovatch (National Academy of Sciences, Ukraine) WORLD SCIENTIFIC, 2020. ISBN: 978-981-121-621-3 (hardcover) This chapter is devoted to the analysis of jamming and percolation behavior of two-dimensional system...

The effects of preliminary vacuum drying (VD) and pulsed electric field (PEF) treatment on characteristics of fried potatoes were studied. The samples were preliminary dehydrated to a different levels (with moisture ratio of MR ≥ 0.2) using VD at sub-atmospheric pressure of p = 30 kPa, and two different drying temperatures, Tv = 40 °C and 70 °C. Af...

Relaxation in a two-dimensional suspensions containing rods was studied by using dynamic Monte Carlo simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state was produced by using a random sequential adsorption model. During the relaxation, the rods underwent translational a...

The structure and properties of soft colloidal systems filled by nano-disks of Laponite® (Lap) are critically reviewed. The known Lap grades, chemical structure and physical properties are described. Various phases formed by exfoliated surface-charged Lap discs in aqueous media are analyzed, accounting for the kinetics of phase transformations and...

The organic substance quercetin, when added to liquid crystal (LC) systems as non-mesogenic dopant significantly affects properties of the LC host. The microphotographs of cholesteric (M5) and nematic (5CB) LC textures evidenced about presence of aggregation quercetin molecules in LC hosts. These results are in agreement with literature data on que...

The effects of aqueous extraction of bioactive compounds from pomegranate peels using conventional extraction (CE) and extraction assisted by infrared irradiation (IR), ultrasound (US), pulsed electric fields (PEF), and high-voltage electrical discharges (HVED) have been compared. For the extractions assisted by US, PEF and HVED, the saturation in...

Aging in a two dimensional suspension containing rods was studied by means of kinetic Monte Carlo simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state was produced using a random sequential adsorption model. During the aging, the rods underwent translational and rotation...

Laponite(Lap) is synthetic clay with platelet particles (a thickness of 1 nm and a diameter of 25 nm) with wide applications in chemical engineering, medicine and cosmetics. An important feature of Lap particles is ability to induce the formation of "empty liquid" structures. The evolution of fresh suspensions of Lap from liquid to gel-like state...

The disintegration efficiencies of microalgal Parachlorella kessleri cells by ultrasonication (US) and high pressure homogenization (HPH) treatments were investigated. The applied procedures included individual US, individual HPH, or combined US followed by HPH treatments. The test concentrations of cell suspensions were 1% and 10% dry matter. The...

The sedimentation of a two-dimensional suspension containing rods was studied by means of Monte Carlo (MC) simulations. An off-lattice model with continuous positional and orientational degrees of freedom was considered. The initial state before sedimentation was produced using a model of random sequential adsorption. During such sedimentation, the...

The effects of Brownian motions on the electrical conductivity and optical transparency of two-dimensional films filled with needle-like particles (needles) have been investigated, using the Monte-Carlo method. The initial state of the system was produced with the use of the random-sequential adsorption process. In the subsequent evolution (aging)...

By means of computer simulation, we examined the effect of dispersity of filler length on electrical conductivity of two-dimensional (2D) composites with rod-like fillers. A continuous approach was used. Highly conductive zero-width rod-like particles were deposited uniformly with given anisotropy onto a poorly conductive substrate. Length of parti...

The ultrasound (US) assisted purification of polyphenols of apple skins by adsorption/desorption on the poly-aromatic Amberlite adsorbent XAD-16 was studied. The adsorption steps were done at different temperatures (T = 25–40 °C) with application of US at different intensities (P = 0–400 W). The desorption steps were tested in aqueous ethanol solut...