Technical Physics Research Articles

Achievement of 26.5 T at 1.8 K and 24.0 T at 4.4 K in a Free Bore of 68-mm Diameter: Successful Commissioning of the HOMER II LTS/HTS High-Field Facility Upgrade

As an upgrade for higher fields, a REBCO high-temperature superconductor (HTS) insert coil with a remarkable cold bore of 68-mm diameter has been constructed with the goal to be routinely operated to attain total fields of 25 T and beyond in HOMER II. HOMER II is the most advanced superconducting high-field facility of the Institute for Technical Physics at the Karlsruhe Institute of Technology. With its basic magnet configuration, consisting of NbTi and (NbX) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn low-temperature superconductor solenoid sections, HOMER II can generate a magnetic field of 20 T in a large bore of 185-mm diameter at a Helium bath temperature of 1.8 K. The REBCO HTS insert coil was manufactured using the rarely implemented concept of layer winding technology and consists of five nested solenoids. In this article, we report on the design of the insert, its construction, and commissioning as well as related aspects. In the initial operation period, magnetic fields of up to 26.5 T were obtained at 1.8 K and 24.0 T at 4.4 K, respectively, without training steps and quenching or other problems.

ЭКСПЕРИМЕНТЫ ПО ИССЛЕДОВАНИЮ ПРОХОЖДЕНИЯ НЕЙТРОНОВ ЧЕРЕЗ СЛОИ ГИДРИДА ЛИТИЯ-7 В УРАНОВОЙ РАЗМНОЖАЮЩЕЙ СИСТЕМЕ С ПРИМЕНЕНИЕМ МЕТОДА НЕЙТРОННО-АКТИВАЦИОННОГО АНАЛИЗА

The paper provides the precision experimental results on fission spectrum neutrons transmission through lithium hydride layers-7 with neutron activation analysis. The experiments were performed in Zababakhin All-Russia Research Institute of Technical Physics” on a critical assembly stand FKBN 2. A cylindrical multiplying system (MS) made of high enriched uranium was used as a source of fission spectrum neutrons. Activation integrals of neutron activation detectors (NADs) located at different points of the composite lithium-7 hydride reflector face-mounted on the cylindrical uranium MS were determined in the experiments. NADs based on nickel, indium, titanium, aluminum and copper were used. NADs of different types were exposed to radiation at power ~25-30 W during 1-1,5 hours. Nickel NAD was used as a monitor. Activation integrals absolute measurement error was determined by a certified technique and ranged from ~4 to ~8 % (2σ). Relative measurement error was determined by statistical accuracy, instrument peaks software processing correctness and was found not to exceed 5,4 % (2σ). Using the data obtained, spectral indices (the ratio of the normalized values of the activation integrals of various detectors types to the one of nickel detector), which provide information on the neutron spectrum were determined.

ЭКСПЕРИМЕНТЫ ПО ИССЛЕДОВАНИЮ ТЕМПЕРАТУРНОГО ЭФФЕКТА РЕАКТИВНОСТИ В ПЛУТОНИЕВЫХ РАЗМНОЖАЮЩИХ СИСТЕМАХ БЕЗ ОТРАЖАТЕЛЯ

The article presents the investigation into reactivity and critical parameters affected by temperature changes in cylindrical and spherical space-effective multiplying systems (MS) of plutonium in α-phase without reflector during integral critical experiments. The experiments were performed in “Zababakhin All-Russia Research Institute of Technical Physics” on a critical assembly stand FKBN-2. Brief description of the experimental set up is provided. During the experiments, the multiplication factors and decay constant of the prompt neutrons were determined at a fixed gap between MS parts and different MS temperatures. Values of MS critical gap at different MS temperatures were established experimentally. The change in MS reactivity is initiated by energy release under the plutonium isotopes alpha-decay. As a result, the change in MS temperature during the experiments without its forced regulation may reach ~40 °C. It is proposed to consider this temperature effect when specifying experimental results including error estimation. The obtained experimental data were used to estimate the temperature coefficients of reactivity. The work results are applied to create benchmark models of the multiplying systems.

Features of the two-stage formation of macroporous and mesoporous silicon structuresя

The aim of this work was the formation of multilayer structures of macroporous silicon and the study of their structural, morphological, and optical properties in comparison with the properties of multilayer structures of mesoporous silicon. The paper presents the results of the development of techniques for the formation of multilayer structures of porous silicon por-Si by stepwise change in the current with two-stage modes of electrochemical etching.The data on the morphology, composition, and porosity of macroporous and mesoporous silicon samples were obtained using scanning electron microscopy, IR spectroscopy, and X-ray reflectivity. It was shown that with the two-stage growth of porous silicon layers, the depth of the boundary between the layers of the structure was determined by the primary mode of electrochemical etching, while the total layer thickness increased with an increase in the current density of electrochemical etching.A comparative analysis of the relative intensity and fine structure of vibrational modes of IR spectra indicated a significantly more developed specific pore surface and greater sorption capacity of mesoporous silicon as compared to macroporous silicon.&#x0D; &#x0D; &#x0D; REFERENCES&#x0D; 1. Pacholski C. Photonic crystal sensors based on porous silicon. Sensors. 2013;13(4): 4694–4713. https://doi.org/10.3390/s130404694 2. Harraz F. A. Porous silicon chemical sensors and biosensors: A review. Sensors and Actuators B: Chemical. 2014;202: 897–912. https://doi.org/10.1016/j.snb.2014.06.0483. Qian M., Bao X. Q., Wang L. W., Lu X., Shao J., Chen X. S. Structural tailoring of multilayer porous silicon for photonic crystal application. Journal of Crystal Growth. 2006;292(2): 347–350. https://doi.org/10.1016/j.jcrysgro.2006.04.0334. Len’shin A. S., Kashkarov V. M., Turishchev S. Yu., Smirnov M. S., Domashevskaya E. P. Effect of natural aging on photoluminescence of porous silicon. Technical Physics Letters. 2011;37(9): 789–792. https://doi.org/10.1134/S10637850110901245. Kheifets L. I., Neimark A. B. Multiphase processes in porous media. Moscow: Khimiya Publ.; 1982. 320 p. (In Russ.)6. Canham L. Handbook of porous silicon. Switzerland: Springer International Publishing; 2014. 733 p.7. Zimin S. P. Porous silicon – material with new properties. Soros Educational Journal. 2004;8(1): 101–107. Available at: http://window.edu.ru/resource/217/21217/files/0401_101.pdf (In Russ., abstract in Eng.) 8. Seredin P. V., Lenshin A. S., Goloshchapov D. L., Lukin A. N., Arsentyev I. N., Bondarev A. D., Tarasov I. S. Investigations of nanodimensional Al2O3films deposited by ion-plasma sputtering onto porous silicon. Semiconductors. 2015;49(7): 915–920. https://doi.org/10.1134/S10637826150702109. Seredin P. V., Lenshin A. S., Mizerov A. M., Leiste H., Rinke M. Structural, optical and morphological properties of hybrid heterostructures on the basis of GaN grown on compliant substrate por-Si(111). Applied Surface Science. 2019;476: 1049–1060. https://doi.org/10.1016/j.apsusc.2019.01.23910. Seredin P. V., Leiste H., Lenshin A. S., Mizerov A. M. Effect of the transition porous silicon layer on the properties of hybrid GaN/SiC/por-Si/Si(111) heterostructures. Applied Surface Science. 2020;508(145267): 1–14. https://doi.org/10.1016/j.apsusc.2020.14526711. Lenshin A. S., Barkov K. A., Skopintseva N. G., Agapov B. L., Domashevskaya E. P. Influence of electrochemical etching modes under one stage and two Stage formation of porous silicon on the degree of oxidation of its surface layer under natural conditions. Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases. 2019;21(4): 534–543. https://doi.org/10.17308/kcmf.2019.21/2364 (In Russ., abstract in Eng.) 12. Buttard D., Dolino G., Bellet D., Baumbach T., Rieutord F. X-ray reflectivity investigation of thin p-type porous silicon layers. Solid State Communications. 1998;109(1): 1–5. https://doi.org/10.1016/S0038-1098(98)00531-613. Lenshin A. S., Seredin P. V., Agapov B. L., Minakov D. A., Kashkarov V. M. Preparation and degradation of the optical properties of nano-, meso‑,and macroporous silicon. Materials Science in Semiconductor Processing. 2015;30: 25–30. https://doi.org/10.1016/j.mssp.2014.09.04014. Ksenofontova O. I., Vasin A. V., Egorov V. V., Bobyl’ A. V., Soldatenkov F. Yu., Terukov E. I., Ulin V. P., Ulin N. V., Kiselev O. I. Porous silicon and its applications in biology and medicine. Technical Physics. 2014;59(1): 66–77. https://doi.org/10.1134/S1063784214010083

Could thermodynamics and heat and mass transfer research produce a fundamental step advance toward and significant reduction of SARS-COV-2 spread?

We are living an extraordinary season of uncertainty and danger, which is caused by SARS-Cov-2 infection and consequent COVID-19 infection. This preliminary study comes from both a mix of entrepreneurial experience and scientific research. It is aimed by the exigency to reach a new and more effective analysis of the risks on the filed and to reduce them inside a necessary cooperation process which may regard both research and some of the economic activities which are damaged by passive protection measures such as indiscriminate lockdowns. This global emergency requires specific efforts by any discipline that regards specific problems which need to be solved urgently. The characteristic airborne diffusion patterns of COVID-19 shows that the airborne presence of viruses depends on multiple factors which include the dimension of microdroplets emitted by a contagious person, the atmospheric temperature and humidity, the presence of atmospheric particulate and pollution, which may act as a transport vehicle for the virus. The pandemic diffusion shows a particular correlation with the air quality and levels of atmospheric pollution. Specific problems need to solved to understand better the virus, its reliability, diffusion, replication, how it attacks the persons and the conditions, which drives to both positive and deadly evolution of the illness. Most of these problems may benefit from the contribution from both heat and mass transfer and the unsteady thermodynamics of living systems which evolves according to constructal law. After the bibliographic research on the virus, emissive and spread modes, and consequent today adopted protection, a detailed analysis of the contributions which may be assessed by research in thermodynamics, heat and mass transfer, technical and chemical physics. Some possible areas of research have been identified and discussed to start an effective mobilization which may support the effort of the research toward a significant reduction of the impacts of the pandemic infection and the economic risks of new generalized lockdowns.

Критический разбор работы "Эксперимент по созданию канала радиосвязи в морской среде"

The article "Experiment to create a radio communication channel in the marine environment" (authors: A.K. Tomilin, A.F. Lukin, A.N. Gulkov), published in the journal "Technical Physics Letters" (2021, vol. 47, Issue 11), from the standpoint of classical physics. The organization of the experiment in the mentioned publication, its interpretation and theory underlying the work are criticized. The proposed material is a methodological commentary and is intended to form consistent approaches in the study and interpretation of further work on the creation of radio communication channels.

New aspects on the performance of a fundamental mode orthogonal fluxgate magnetometer based on amorphous wire cores

The performance of a fundamental mode orthogonal fluxgate magnetometer based on Co68.15Fe4.35Si12.5B15 amorphous wires produced at National Inst. of R. &amp; D. for Technical Physics Iasi is presented. Our efforts are concentrated on reducing the sensor noise (magnetic noise + noise of the electronics) and at the same time on increasing the sensitivity in order to achieve a maximum signal to noise ratio. Making a parallel between conventional orthogonal fluxgate and fundamental mode orthogonal fluxgate operating principle, the differences in responsivity and noise have been explained based on magnetization mechanisms involved in the core.

METAPHORS OF EURISTIC OPTIMIZATION IN CONSTRUCTION TASKS

A promising direction for solving complex optimization problems in construction is the heuristic approach, which is due to the objective ambiguity of the construction industry and provides a choice from a set of solutions based on analogy, similarity, similarity of the heuristic model or algorithm, which will take into account the experience of natural process to obtain a solution of complex many modal, many parametric and multicriterial problems, and the objective function of the activity is complex, very extreme, with gaps, with obstacles sometimes poorly defined (as a fuzzy function on fuzzy sets). It should be noted that the observation of natural neural networks, social forms of existence, populations and species is currently relevant and widely used. At one time, bionics gave impetus to the development of technical physics and engineering in general. In information technology, the study of wildlife processes can accelerate the development, creation and use of algorithms and mechanisms for processing information in wildlife, which are the result of long-term evolutionary selection. Such algorithms are called algorithms based on metaphor (metaheuristics or metaphor). To use metaphors to understand the strategy used, the method must be translated into the language of the applied field – construction and mathematical methods – in standard optimization terminology. An overview of the currently most common heuristic models and algorithms is performed, taking into account their features and areas of application. The features that are characteristic of construction tasks and the reasons for which they are due, and the relationships that are assigned to them. The main tasks solved in the construction industry for application in relation to their heuristic optimization are defined and considered. Based on the concepts of construction tasks, fields of construction tasks, information object of construction tasks, the analysis of the choice of metaphor for the task in the construction industry is carried out and the scheme of selection of metaphor is offered.

Preparation of AlN film grown on sputter-deposited and annealed AlN buffer layer via HVPE* *Project supported by the National Key Technologies R&D Program of China (Grant No. 2017YFB0404100) and Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences.

AlN films grown on sputter-deposited and annealed AlN buffer layer by high temperature hydride vapor phase epitaxy (HVPE) have been fabricated and structurally characterized. The crystalline quality and surface morphology of as-grown AlN films with various V/III ratios were studied and compared. The XRD results showed that the crystalline quality of the AlN film could be optimized when the growth V/III ratio was 150. At the same time, the full width at half-maximum (FWHM) values of (0002)- and ()-plane were 64 arcsec and 648 arcsec, respectively. As revealed by AFM, the AlN films grown with higher V/III ratios of 150 and 300 exhibited apparent hillock-like surface structure due to the low density of screw threading dislocation (TD). The defects microstructure and strain field around the HVPE-AlN/sputtered-AlN/sapphire interfaces have been investigated by transmission electron microscopy (TEM) technique combined with geometric phase analysis (GPA). It was found that the screw TDs within AlN films intend to turn into loops or half-loops after originating from the AlN/sapphire interface, while the edge ones would bend first and then reacted with others within a region of 400 nm above the interface. Consequently, part of the edge TDs propagated to the surface vertically. The GPA analysis indicated that the voids extending from sapphire to HVPE-AlN layer were beneficial to relax the interfacial strain of the best quality AlN film grown with a V/III ratio of 150.

Erratum to: Several Articles in Journal of Applied Mechanics and Technical Physics

Erratum to: Several Articles in Journal of Applied Mechanics and Technical Physics

Assessment of Temperature Reactivity Effect in Compact Plutonium Systems

This work considers the effect of temperature change in plutonium breeder systems (BS) on the reactivity and critical parameters thereof in the course of integral critical experiments conducted at the All-Russian Scientific Research Institute of Technical Physics (VNIITF). The BS temperature reactivity factors (TRF) $$\frac{{\partial \rho }}{{\partial T}}$$ were assessed according to the multiplier factor Q depending on the BS temperature and according to the change in decay constant α. Experimental and estimated (using Monte Carlo method) TRF values were compared. Extreme gaps in the BS under different temperature values were measured (in an operating mode with a natural heat sink and with the use of an air-cooling system).

URGENT COMMUNICATION The Deceleration Curve of the von Neumann Spike Is the New Feature of Detonating Explosives

A new characteristic of detonating explosives is proposed—the deceleration curve of the von Neumann spike. An example of plotting such a curve on the basis of experimental data obtained at the All-Russian Scientific Research Institute of Technical Physics for detonating plastic-bobded TATB is given.

Воздействие некоторых сложных хемостимуляторов и модификаторов на термооксидирование InP

Воздействие некоторых сложных хемостимуляторов и модификаторов на термооксидирование InP

Non-force electromagnetic fields

The non-force magnetic fields were first predicted by Chandrasekhar in 1956 in his well-known published work [1]. Since then there have appeared a large number of theoretical studies [5,6,15,17] with the research into various aspects of physical manifestations of non-force magnetic fields. However by now their existence in the technical physics and in laboratory experiments has not been experimentally confirmed [30]. Nevertheless the indistinct presence on the Earth of such fields was, in a sense, discovered in the natural electromagnetic field much earlier.

‘The Miracle of Density': The Socio‐material Epistemics of Urban Densification

AbstractDespite being a foundational concept in urban studies and practice, urban density has remained relatively immune to critical study. In the midst of contemporary global housing and environmental crises, density has become an even more paradigmatic, almost common‐sense urban category and planning idiom. This article interrogates urban density as a socio‐material epistemology, as a knowledge form and practice about people, things and their mutual entailments. Based on archival and ethnographic research among city planning networks in Bogotá, Colombia, I draw attention to the political projects that are encoded in the supposedly technical physics and aesthetics of urban densification. Far from a stable, descriptive category, actors actively mobilize density to reimagine and craft urban worlds. The article tracks the shifting deployments of density in Bogotá from the middle of the twentieth century to the present, from approaches aimed at removing urban crowds and stimulating modern densities to recent projects aimed at regulating densification and rendering it more inclusionary. The article's grounded ethnographic analysis critically illuminates the ways in which the grammar of density—as a taken‐for‐granted metric of urban transformation and an ideology of socio‐materiality—both shapes and limits the praxis of urban politics.

Improving methods and facilities of Earth’s orientation parameters evaluation in Main metrological center of State service for time, frequency and Earth’s orientation parameters evaluation

The results of improvement of methods and facilities of Earth’s orientation parameters in Main metrological center of State service for time, frequency and Earth’s orientation parameters evaluatio in the last five years are considered. The hardware and software are modernized. As result Main metrological center of State service for time, frequency and Earth’s orientation parameters evaluation has program correlator now, the calculation thechnic was improved, Analysis Center of Main metrological center of State service for time, frequency and Earth’s orientation parameters evaluation was created. The Russian metrological institute of technical physics and radio engineering has satellite laser ranging station of new generation now. This station was created by Institute for precision instrument engineering. The new software for satellite laser ranging processing and lunar laser ranging processing was created. The new sofware of the global navigation satellite systems processing was developed. The software for very long base interferometry data processing and software for combination were modernized. Development of evaluation and predictioning facilities of Earth’s orientation parameters Russian metrological institute of technical physics and radio engineering was provided according to modern international direction. This allowed to provide work of evaluation and predictioning of Earth’s orientation parameters at the high international level.

Reference materials for inductively coupled plasma methods (ICP standards) produced by VNIIFTRI

For the metrological assurance of the high-precision inductively coupled plasma methods, the Russian Metrological Institute of Technical Physics and Radio Engineering (VNIIFTRI) developed four types of certified reference materials (CRMs) of the mass fraction of metals in solutions (ICP CRM). The permissible certified values of the element mass fraction (mass concentration) in the developed ICP CRM range from 800 mg/kg to 1200 mg/kg (from 800 mg/dm3 to 1200 mg/dm3). The developed ICP CRMs can be used for ensuring the metrological traceability of measurements in inorganic analyses to the State Primary Standard for units of the mass fraction and mass (molar) concentration of inorganic components in aqueous solutions based on gravimetric and spectral methods GET 217-2018.

Teaching physics for tomorrow: Equipping students to change the world

Why should engineers have all the fun?

Структурные и спектральные особенности композитов на основе белковых сред с одностенными углеродными нанотрубоками

Исследованы структурные особенности нанокомпозитов, полученных при лазерном облучении водно-белковых сред с одностенными углеродными нанотрубками (ОУНТ), электродуговым (ОУНТI) и газофазным методами (ОУНТII). С помощью спектроскопии комбинационного рассеяния нанокомпозитов определен нековалентный характер взаимодействия нанотрубок с молекулами белков. Белковая составляющая в нанокомпозитах подверглась необратимой денатурации и может выступать в качестве связующего биосовместимого материала, который является источником аминокислот для биологических тканей при имплантации нанокомпозитов в организм. Образцы, изготовленные из ОУНТI, с меньшим диаметром и длиной имели наиболее однородную структуру. При увеличении концентрации от 0.01 до 0.1 % происходило увеличение среднего размерамикропор от 45 до 85 мкм и пористости образца в общем с 46 до 58 %. При этом доля открытых пор для двух типов концентраций ОУНТI составила 2 % от общего объема композита. В нанокомпозитах на основе ОУНТI показано наличие мезопор. Увеличение концентрации нанотрубок привело к уменьшению удельных значений поверхности и объема пор образца. Исследованные нанокомпозиты могут использоваться в качестве тканеинженерных матриц для восстановления объемных дефектов биологических тканей&#x0D; &#x0D; REFERENCES&#x0D; &#x0D; Eletskii A. V. Carbon nanotubes. Usp., 1997, v. 40(9), pp. 899–924. https://dji.org/10.1070/PU1997v040n09ABEH000282&#x0D; Tuchin A. V., Tyapkina V. A., Bityutskaya L. A., Bormontov E. N. Functionalization of capped ultrashort single-walled carbon nanotube (5, 5). Condensed matter and interphases, 2016, v. 18(4), pp. 568–577. URL: http://www.kcmf.vsu.ru/resources/t_18_4_2016_015.pdf (in Russ.)&#x0D; Dolgikh I., Tyapkina V. A., Kovaleva T. A., Bityutskaya L. A. 3D Topological changes in enzyme glucoamylase when immobilized on ulrta0short carbon naotubes. Condensed matter and interphases, 2016, v. 18(4), pp. 505–512. 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Atomically resolved magnetic structure of a Gd-Au surface alloy

We gratefully acknowledge financial support from the Office of Naval Research via Grant No. N00014-16-1-2900. Moreover, M.A. and J.B. acknowledge funding from the Spanish MINECO under Contracts No. MAT2013-46593-C6- 4-P and No. MAT2016-78293-C6-5-R as well as the Basque Government Grants No. IT621-13 and No. IT-756-13. T.H. acknowledges support by the DFG under Grant No. HA 6037/2-1. E.S. acknowledges financing from Polish budget funds for science in 2014–2017 as a research project in the program “Diamond Grant” No. 0084/DIA/2014/43. M.H. acknowledges the support from the Ministry of Science and Higher Education in Poland within Project realized at Faculty of Technical Physics, Poznan University of Technology, and Poznan Supercomputing and Networking Center (PSNC)