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Titanium dioxide (TiO2) micropowders widely used in modern food industry may contain particles in highly-toxic nanoform. Unlike micrometer-sized crystals, which cannot penetrate cell membranes, TiO2 nanofraction causes the liver function damage, intestinal inflammatory response, and oxidative metabolism imbalance. In this study, we demonstrate the possibility of utilizing Raman spectroscopy for fast detection of nanofractions against the background of anatase TiO2 micropowders. The results reveal that the presence of nanofractions leads to the appearance of several physically-grounded features in Raman spectra of TiO2 associated with the weakening of the selection rules for first-order scattering processes, the size-related frequency shift of Raman-active vibrations, and the enhanced contribution of Raman processes related to the surface states. In combination with standard microfiltration methods, these Raman markers provide a simple method for express control of highly-toxic nanofractions in TiO2 micropowders used in the food industry.

A number of optimal parameters determining the efficiency and rate of the strontium removal by a granular sorbent synthesized by the interaction of KMnO4 and concentrated H2O2 solution have been determined. The optimal drying temperature was found to be 400 °C at an average grain size of 0.1–0.2 mm. The average value of the strontium distribution coefficient in seawater equaled to 1.4–1.5 × 103 mL/g at the V/m ratio of 1000 mL/g ratio. The maximum value of adsorption in a single-component solution calculated using the Langmuir equation was equal to 1.0–1.1 mmol/g and corresponded to total dynamic exchange capacity. As the number of sorption-desorption cycles increased, total dynamic exchange capacity gradually decreased. The efficiency of Sr-90 removal from real liquid radioactive waste streams has been evaluated.

The technology of obtaining coatings consisting of alumina nanoparticles and their agglomerates is presented. The transport properties of coatings and the change of these properties with time are investigated. The dependence of the height of capillary ascent on the quantity of deposited nanofluid on substrates has been established. An estimate of the change in the height of liquid rise and of the permeability of a coating with the change in the size of particles has been made. Deterioration of the transport properties of porous coatings consisting of alumina nanoparticles with time is investigated, and the possibility of restoring these properties is shown.

The switching of shunt reactors in an electrical network is in many cases accompanied by reignition of the arc in the circuit breaker and the occurrence of dangerous overvoltage in the network. To limit such overvoltage, controlled-switching devices are used to switch off the reactor in the optimal phase of the current. To select the optimal switching conditions, the switching processes are analyzed, taking into account the intuitively clear difference between the switching conditions for three-phase and single-phase shunt reactors due to the electrical and/or magnetic coupling between the phase windings. The proposed method of analysis is universal for all types of three-phase shunt reactors due to the use of a universal four-legged star equivalent circuit. The reactor phases are switched off, synchronized against the phase Avoltage curve, in the sequence A → C → B to minimize the total switching time.

The spectral luminescent characteristics of LiF:U crystals are studied. In addition to an impurity of uranium, impurities of magnesium and hydroxyl are present in each investigated sample. Impurities of magnesium and hydroxyl enter the crystal when grown in air according to Kyropoulos. The absorption spectra of the crystal before and after radiation treatment, measured at room temperature and liquid nitrogen temperature, are presented. A correlation is found between the absorption spectra in the ultraviolet (UV) and visible regions and the vibrational spectra of hydroxyl ions in the free state and in complexes with metals. The luminescence spectra are measured upon excitation with different wavelengths. The role of hydroxyl and magnesium in the differentiation of uranium centers is determined.

Factors affecting the operating parameter of a memristor (Roff/Ron) are considered. The increase in this parameter as the current of a magnetron and the period of irradiation are increased while preparing a LiF thin film with copper nanoclusters is studied. The synaptic behavior of a memristor based on this film is demonstrated.

Low-temperature absorption spectra at temperatures of range of 7.2–300 K in MgF2 and LiF-O,OH crystals were studied to investigate the electron-phonon interaction of radiation-induced color centers in these crystals. The coupling strength (S) with the phonons of the lattice of electronic-vibrational transitions was determined from the ratio of intensities in the zero-phonon line and the integrated absorption band. The nature of the color centers associated eith the absorption band at 390 nm and the emission at 490 nm in LiF-O,OH crystals and for the absorption band at 370 nm and the emission at 420 nm in MgF2 crystals was determined from value of S.

Two types of thermally unstable U1 centers are created in LiF:Mg,OH crystals by γ−irradiation at low temperatures. One of them is influenced by impurity complexes containing magnesium ions Mg2+. Another type of U1 center is perturbed by impurities of OH¯ ions. Temporal dynamics of conversion of U1 centers and F2+ and F2+** color centers after crystal was heated from temperature of 80 K to 300 K is presented.

The results of spectral–temporal studies of the filament plasma emission in air with a time resolution of 2 ps were presented. The filament was created by laser radiation with pulse duration of 60 fs and wavelength of 940 nm. It was shown that a spectral composition of the filament plasma depended on the numerical aperture (NA). At NA > 0.035, the atomic and ion lines of oxygen and nitrogen dominate in the spectrum on the background of an intense continuous continuum in the visible region. Molecular lines of the second positive system of nitrogen and the first negative system of molecular ions appear in the spectrum for NA 0.03. In case of NA 0.01, the spectrum consists of only the molecular and ion lines of N 2 and N 2 + . The emission intensity maxima of these lines delay relative to the laser pulse. The atomic lines begin to glow per (80–100) ps after the laser pulse. The characteristic time of the luminescent lines decay at 1/e level for ions is 18 ps, for molecules is 27 ps, and for atomic lines is 20 ns. Rapid decrease in the intensity of molecular lines emission is due to the deactivation of the particles upper states by electrons. The formation of N 2 + ( B 2 Σ u + ) excited states is most likely through their N 2 + ( X 2 Σ g + ) ground state in the process of multiphoton absorption of pumping radiation by nitrogen molecules and subsequent their excitation by electron impact.

The Ni-nanoparticles, being similar to the nanocores of the Ni/Au core–shell nanoparticles, are made up of the structural domains with the dimensions about 1 nm. It is experimentally shown in this work for the first time by the combination of the small-angle X-ray scattering (SAXS) and the powder X-ray diffraction (XRD). The atomic structure of these domains is not a face-centered cubic lattice (FCC) inherent in the bulk state of Ni. This fact has been established by using the transmission electron microscopy (TEM) and XRD, calculated and confirmed by the observed features of an anodic oxidation and the differential scanning calorimetry (DSC) results for the investigated Ni-nanoparticles. Thus, the Ni-nanocores are composed of the domains with a structure formed by the icosahedra in the synthesis often used to obtain the core–shell nanoparticles.

In this study, we investigated the mutual influence of metal nanoparticles and the color centers in lithium and sodium fluorides based on absorption spectroscopy, infrared spectroscopy, atomic force microscopy, and photoluminescence method. Atomic force images of the fresh cleavage of the γ-irradiated and photo-bleached single crystal of sodium fluoride indicated the photo-induced aggregation of F color centers followed by the formation and integration of sodium nanoparticles. The thermo-induced changes in the photo-bleached samples exhibited the inverse trend, i.e., disintegration of the nanoparticles and restoration of a crystal lattice. In the photo-bleached γ-irradiated lithium fluoride crystals, we detected the luminescence of F3 centers and confirmed that the mechanism of nanoparticle formation was due to aggregation of the color centers.

Langmuir-Blodgett films modified by an electrochemically active compound, such as cobalt hexacyanoferrate, are of interest to create water-insoluble film electrodes with a high concentration of active centers and a low response time. The possibility of introducing cobalt hexacyanoferrate nanoparticles stabilized by sodium hexametaphosphate in octadecylamine monolayers with subsequent transfer them to a solid substrate by the Langmuir-Blodgett method is shown. Cobalt hexacyanoferrate nanoparticles were obtained by gradual mixing of an equimolar reagents mixture with the addition of sodium hexametaphosphate as a stabilizer. The size of nanoparticles were determined by the laser diffraction method, the size of their main number was about 12 nm. The hydrosol of the nanoparticles stability was studied photometrically in the pH range 2–4. The π-A octadecylamine monolayers isotherms on a subphase containing cobalt hexacyanoferrate nanoparticles were studied at the same pH values. According to the obtained data, optimal conditions for the monolayers transfer to a solid substrate by the Langmuir-Blodgett method were chosen. The morphology of the resulting films was studied on the surface of solid substrates. The electrochemical properties of electrodes based on Langmuir-Blodgett films in various solutions of electrolytes were studied by using the cyclic voltammetry and potentiometry.

The structure, the mechanical properties, and the electrical conductivity of the Cu–0.7% Cr–0.9% Hf alloy subjected to equal-channel angular pressing (ECAP) followed by aging are studied. The treatment that consists of ECAP and aging at 450°C for 2.5 h is shown to result in a high strength (σu = 605 MPa) and a high electrical conductivity (78% IACS) of the alloy. This combination of properties increases the resistance of the contact welding electrodes made of an ultrafine-grained Cu–0.7% Cr–0.9% Hf alloy as compared to its initial coarse-grained state.

In this article the possibility of obtaining Langmuir-Blodgett films on the basis of octadecylamine monolayers containing nanoparticles of hexacyanoferrates of various metals was shown. A comparison was made between different methods for obtaining these particles. Nanoparticles were produced using sodium hexametaphosphate as a stabilizer, their average size were determined by laser diffraction. The isotherms of compression were studied for monolayers on a subphase containing nanoparticles. Optimal conditions for the transfer of monolayers to a solid substrate were chosen according to the data obtained and their morphology was studied by scanning electron microscopy. The cyclic voltammetry method also confirmed the successful transfer of a monolayer to a solid substrate and showed the manifestation of the electrochemical properties of the obtained substrates.

The hysteresis and kinetics of the electro-optic response of multilayer ferroelectric polymer Langmuir–Blodgett films have been investigated.

In the present paper, the effect of magnesium nanoparticles implanted in a LiF crystal on the optical properties of color centers is studied. The transmittance spectra and AFM images demonstrate effective formation of the color centers and magnesium nanoparticles in an implanted layer of ∼ 60–100 nm in thickness. Under thermal annealing, a periodical structure is formed on the surface of the crystal and in the implanted layer due to self-organization of the magnesium nanoparticles. Upon excitation by argon laser with a wavelength of 488 nm at 5 K, in a LiF crystal, implanted with magnesium ions as well as in heavily γ-irradiated LiF: Mg crystals, luminescence of the color centers at λmax = 640 nm with a zero-phonon line at 601.5 nm is observed. The interaction of magnesium nanoparticles and luminescing color centers in a layer implanted with magnesium ions has been revealed. It is shown that the luminescence intensity of the implanted layer at a wavelength of 640 nm is by more than two thousand times higher than that of a heavily γ-irradiated LiF: Mg crystal. The broadening of the zero-phonon line at 601.5 nm in the spectrum of the implanted layer indicates the interaction of the emitting quantum system with local field of the surface plasmons of magnesium nanoparticles. The focus of this work is to further optimize the processing parameters in a way to result in luminescence great enhancement of color centers by magnesium nanoparticles in LiF.

A hot pressing method is developed for aluminum powder with preliminary sample and die heating to 600°C. The effect of modifying aluminum with carbon nanotubes in an amount of 0.01–1 wt.% is studied. The microstructure, phase composition, and mechanical and electrical properties of the specimens obtained are determined. It is established that the best uniformity and mechanical strength applies to aluminum specimens containing small additions of nanotubes, i.e., 0.01–0.05 wt.%. An increase in carbon nanotube content above 0.1 wt.% is a reason for the occurrence of inhomogeneity formed as a result of nanotube conglomerates.

Boiling curves of distilled water and isopropanol in 12.5x3x0.2 mm microchannel with rigid inlet and outlet lines are obtained. Critical heat flux is calculated for isopropanol by using the previously obtained correlation for water.

In this work, coatings of nanoparticles of aluminum oxide are investigated. Photos were obtained using an electron and optical microscope. A method is proposed for the formation of a coating of nanoparticles with and without agglomerates. The transport properties of nanoparticles of aluminum oxide, silicon carbide, titanium oxide and diamond have been investigated. The effect of agglomerates of nanoparticles on the rise of liquid has been determined.

The characteristic energy of distributions of Ag and Cu nanoclusters in LiF-based thin films is estimated from the slope of the I–V characteristic, built in double logarithmic coordinates logI = f (logU). It is shown that the energy states of small clusters lie above the bottom of the conduction band and form a potential barrier, while the energy states of large clusters lie below the bottom of the conduction band and form a potential well. The change in the positions of energy levels along with nanocluster size and the effect of quantum limitations imposed on the electrical and optical properties of the system are confirmed experimentally.

Proton-conducting membranes have been obtained by sol–gel synthesis involving tetraethyl orthosilicate and sulfonated suspension copolymers of styrene with allyl glycidyl ether. The membranes are gels consisting of a polymer matrix, in which silica particles are uniformly distributed. The synthesized membranes are characterized by the proton conductivity of up to 4.21 × 10–2 S/cm at 343 K and 75% humidity, an ion exchange capacity of 3.5 meq/g, a proton-transfer activation energy of 25.2 ± 2.6 kJ/mol, thermal stability of up to 130°C, and mechanical strength (tensile modulus of elasticity, 322 MPa).

The effect of impurities on the efficiency of the formation of color centers and hydrogen-bonded molecular complexes upon exposure to various radiations in lithium fluoride crystals grown in air is studied. The results of experiments for measuring optical properties, IR vibrational spectra, luminescence, and thermally stimulated luminescence are presented. The fact that the band in the range of 1800–2300 cm–1 corresponds to stretching vibrations of a complex with strong hydrogen bond is proved based on the Fermi-resonance perturbation in the region of 2080 cm–1, shaped as the Evans hole and bands A, B, and C. It is shown that the composition of these complexes includes an OH– ion and an HF molecule. The crucial role of O2‒ V + oxygen dipoles in the aggregation efficiency and gradient distribution of color centers and radiation resistance of hydroxyl ions is revealed. It is shown that products of radiation decomposition of OH– ions stimulate, while decay of O2‒ V + dipoles suppress, the formation of positively charged color centers.

This paper presents the results of experimental studies on the formation conditions of a highly directional supercontinuum (SC) produced via filamentation of a femtosecond laser pulse in air. The laser beam had an energy of 8–15 mJ, radiation wavelength of 940 nm and pulse duration of 70 fs. A spherical mirror, with or without aberrations, was used to focus the laser beam. It is shown that a SC forms behind a visible filament through a step-by-step conversion of the spectral composition from long wavelength to short wavelength (to 350 nm). The radiation is most stable when it is generated in the presence of aberrations in the wave front of the laser beam. On the track section 35–135 cm from the filament, radiation propagates in the form of a spatially stable structure similar to a soliton with a transverse dimension ≤300 µm. In this case, the SC significantly differs from the conical off-axis emission that occurs in the aberration-free filament, in that it displays a divergence close to the diffraction limit, linear polarisation and a shorter-range wing of the spectrum. The infrared component of the SC has a duration 2.8-times shorter than the pulse duration of the initial laser beam.

The distribution of pixels with high-value dark current in CMOS image sensors irradiated by protons with the energy of 1000 MeV and neutrons with a continuous spectrum simulating the energy spectrum of atmospheric neutrons is explored. Data on generation of spike clusters in the irradiated sensors and the exposure time influence on the cluster parameters are obtained.

The uncontrolled energizing of shunt reactors is accompanied by appearance of a significant DC-component in current, leading to saturation of power and instrument transformers in adjacent network [1], [2]. DC-component causes high inrush current that have an electrodynamic impact on power network equipment [3]. In order to prevent these negative consequences, controlled switching devices providing reactor optimal energizing instant are used.

Experimental results are used to justify the method of determination of the quality of resistance welding of samples of interconnections of lead-acid batteries using torsion tests. The orig...

Results are given for comprehensive research concerning fields of metallurgy, nanomaterials, and ecology. Taking account of theoretical concepts and known practice of modifying gray cast iron, a new ultrafine modifier is considered containing carbon with increased chemical activity. It is established that carbon foam, electrolyzer dust from electric filters, and alumina passing through a dry gas cleaning system, have carbon nanostructures in their composition. Raw material composition for preparing modifying additive, procedures, and experimental materials are provided. Results are given from a series of cast iron melts with a different modifier content and a method for adding it with replacement of 50% of standard metallurgical graphite by the carbon-containing part of carbon foam. The effect of modifier on phase formation during gray cast iron solidification by means of cooling from a liquid condition is considered. A test cast iron sample and reference cast iron are analyzed chemically, and mechanical properties are analyzed. It is established that a modifier makes it possible to improve gray cast iron grade. Theories are proposed for carbon nanotube formation during aluminum production. A technology is provided for extracting carbon structures from starting raw material. It is shown that with preparation of one ton of aluminum using the production solutions developed for decontamination and utilization of industrial waste it is possible to produce modifier based on highly organized carbon nanostructures.

The microstructure of lithium fluoride thin films deposited on a glass substrate by thermal vacuum evaporation was investigated. An additional annealing of the films in air at temperatures of 400, 500, and 600°C resulted in an increase in the size of grains forming the film, as well as in the transformation of luminescence spectra of the initial and annealed samples before and after their X-ray irradiation used to generate in the films color centers that played the role of luminescent probes. It was found that an increase in the annealing temperature with an increase in the size of grains leads to a decrease in the intensity of the characteristic photoluminescence bands of color centers in lithium fluoride and to the appearance of new luminescence bands that are not characteristic of this material. Based on the results of the X-ray powder diffraction analysis, it was concluded that the increase in the grain size is caused by the change in the chemical composition of the films primarily due to the interaction of lithium fluoride with the substrate material.

The results of investigation on high-temperature gas-phase removal of impurities from a granulated quartz concentrate are presented. Various gaseous media and treatment methods are considered. The influence of the main process parameters on the impurities content in raw quartz are estimated and the optimal values are selected.

In this paper, we consider the use of the polarization-optical method for assessing the stress-strain state of films of polymeric material in the restored tribomechanical system “bearing ring - housing” and the dependences for determining the magnitude of the principal stresses are proposed. When studying the stress-strain state, compounds with a diameter of the contact surface of 40 mm from an optically sensitive material imitating an adhesive layer were used as models. The photoelasticity method showed that the maximum stresses occurred on the axis of symmetry of the model, and the contact arc was 180 degrees. A qualitative picture of the strips indicates the identity of the stress-strain state of the adhesive joint model both for the uniform gap model and for the eccentricity models.

Heat transfer crisis was investigated during water boiling in a microchannel without coating and with coating of aluminum oxide nanoparticles. Experiments were performed on an advanced setup with a horizontally located microchannel with dimensions of 12.5x3x0.2 mm. Calculation of the critical heat flux in the microchannel without coating and with a coating from nanoparticles, carried out by formulas for heat transfer crisis in a horizontal pipe with microporous coating and one-sided heating. For the microchannel coated with nanoparticles the critical heat flux was calculated for the conditions of no influence of liquid subcooling and initial section. The satisfactory agreement between the experimental and calculated data was obtained. dependences of the critical heat flux from the coating thickness and characteristic size of particles were also shown. However, the data array is limited and needs to be expanded what will improve the equations for critical heat flux in a microchannel with nanoparticles coating.

In the work, porous coatings of alumina nanoparticles are investigated. The coatings were formed by various methods. The dependence of the lift height of the nanofluid on its volume was established. The properties of the coating are compared with and without microtrenches.

Thermal recycling and disinfection of waste products in different physical states represent a comprehensive solution to the problem of waste utilization. The utilization of waste materials with high moisture content (more 70…75%) is associated with a need to evaporate a significant volume of water and causes, as a consequence, substantial additional expenses on an energy source. To cut costs related to the utilization of wastes with a high amount of water it is suggested using a coal cleaning product – a coal-water slurry fuel. The direct combustion of incompletely mechanically dehydrated (to 70-75%) wastes with high water content (cake) is an economically efficient process. However, it poses a severe problem of combustion stabilizing. The paper presents outcomes of the research into the stabilization of thermal recycling waste materials with a high level of moisture by means of low-temperature plasma in the adiabatic vortex combustion chamber. To control a burning process in the technology adapter low-temperature plasma is supplied into the base of flame. An output of a plasma generator (power supply source) is estimated as 1 kW power input per 13 kg/h suspension fuel. A dynamic range of heat output for a coal-water slurry fuel and wastes is determined to be 70-100% when generating thermal energy and utilizing wastes with high moisture content by means of low-temperature plasma as a stabilizer of a combustion process. Experimental studies carried out on a machine simulator have proven the efficiency of low-temperature plasma for utilization and disinfection of waste products in commercial farming.

Film and drop condensation are important processes in technics. This article includes the features of macroscale heat transfer intensifiers under film condensation, microscale and nanoscale heat transfer intensifiers under drop condensation. It is noted that condensation heat transfer may be influenced by the wall material. The mechanism underlying this influence is the nonuniform distribution of the wall temperature in the case of a low heat conduction coefficient. Based on the research results, a dependence of the wetting angle from the combined coating consisting of 7 alumina oxide and water repellent is obtained.

The analytical signal for atomic-emission microwave plasma (AEMP) spectral analysis method is studied. It is shown that the signal consists of two parts: background signal, proportional to content of the analytical element in a sample shaped by submicron particles and metalorganic compounds; pulse signal, proportional to content of analytical element in coarse discrete particles. The “dynamic discrimination” algorithm is suggested that allows measuring the element content in a liquid or powder ore sample independently of the content shape using AEMP method. It is shown that atomic absorption (AA) and AEMP measurements of Fe, Cu agree within error for samples both low and high in content of element in submicron particles.

Impregnation of an industrial dielectric polyethylene terephthalate film having through-track micropores with new phosphorus-containing proton-conducting ionic liquids allows the electrical conductivity of this film to be increased by 7–8 orders of magnitude. The plasma-radiation curing of the vinyl ionic liquid leads to formation of a new proticinterpolymer composite film in the track holes of the film.

The formation of U1-centers in LiF:OH crystals, γ-irradiated to a dose of 1.3×104 C/kg at a temperature of 80 K, is considered in this study. The band at νmax = 2315 cm−1 is the main band of local interstitial hydrogen ions vibrations, which is more stable at room temperature (in a few month) than the additional band at νmax = 2260 cm−1. It is shown that U1-centers are Hi¯(OH¯) defects. The stabilization of interstitial hydrogen ions is occurs by the OH¯ impurity ions. The efficient formation of positively charged F2+ and F3+ color centers is due to electron traps are Hi¯(OH¯) hydrogen centers. The efficiency of F2+- and F3+-like laser color centers formation in LiF crystals is connected with thermal decomposition of Hi¯(OH¯) defects.

The effect of astigmatism on laser air filamentation was studied numerically and experimentally. Limited supply of energy to the filament is shown to be the main feature of aberrational focusing, which facilitated the organization of quasi-solitons in the post-filament region. Quasi-solitons are realized due to the balance between linear diffraction and Kerr nonlinearity in the presence of background environment around zones with increased intensity. A highly directional SC of visible light is formed outside the visible filament zone in the resulting spatial quasi-solitons.

A system for automatic regulation of the process of butt welding of T-joints in wire and casing components is described. The system uses as the feedback parameter the mean rate of decrease of the force in the joint in the time period from the moment of application of welding current to heating the metal to the welding temperature, and the regulating effect is the duration of the welding current pulse. The results of experiments carried out to determine the special features of the welding process with automatic regulation are presented.

Laser-induced changes in the intervertebral discs were studied by the method of atomic force microscopy. Alteration of the proximal caudal intervertebral discs was modeled in rats: puncture and exposure to diode laser (2, 3, or 5 W) in constant or pulse regimens or only puncture (control). Nanostructure of disc surface was estimated by surface skewness, root mean square and average roughness, and coefficient of kurtosis. Maximum positive effect and signs of regenerative changes in the surface microstructure of the intervertebral discs were found after exposure to laser (2-3 W) in constant or pulse regimens.

Temperature dependences of the surface conductivity of LiF-based thin films with Cu and Au nanoclusters are measured to determine the electrotransport activation energy and I–V characteristics of the films are obtained. The memristor effect is observed in the investigated thin films, and the ratio between film resistances at the moments the electric field is switched on and off is determined. The high potential of copper nanoclusters is demonstrated.

The paper describes a new sensor for the spatial registration and measurement of particle parameters in near and deep space. The following modern materials are applied in the sensor structure: a PVDF piezoactive film and lightweight heat-shielding high-temperature aerogel. The results from studying the aerogel morphology as well as its thermal conductivity depending on the air temperature are presented. The thermal conductivity of a SiO2-aerogel is compared with one of foreign aerogels and air. Its elemental quantitative chemical composition is determined.

Production and use of modifiers for cast iron and steel are analyzed. Compositions of standard industrial modifiers are considered with evaluation of trends in their development. It is shown that a promising area for creating a new generation of fundamentally different types of modifier is nanomodification of molten iron-carbon alloys.

The system of proton-beam formation for proton ophthalmology has been numerically simulated using the Geant4 program package. Data on the efficiency of narrow- (“pencil”) and wide proton-beam transport are presented. It is established that the use of a wide beam transport is advantageous, since it makes a significant decrease in the background-radiation level in a proton-therapy room possible and simplifies the beam-formation system.