Physical Terms Research Articles

ОСОБЕННОСТИ РОССИЙСКОГО ФАРМАЦЕВТИЧЕСКОГО РЫНКА

The pharmaceutical market in Russia in the current environment is one of the most dynamically developing, which is associated with its high importance for ensuring national security. The change in the foreign policy environment against the background of the events of 2014 showed the negative aspects of the country's previously existing dependence on the import of pharmaceutical products, defining the implementation of the import substitution strategy in the field of drug supply as a long-term benchmark for the development of the industry. However, its implementation actually ran into a number of difficulties, the most important of which is the insufficient level of development of the country's scientific and technical potential in this industry. In the course of the study, the analysis of the main indicators of the dynamics and structure of the domestic pharmaceutical market in physical and value terms, identification of the main trends and their causes was carried out. It has been established that in the past 3 years the domestic pharmaceutical market has been developing, which is confirmed by a steady trend towards an increase in its value from 1.6 to 1.8 trillion. rub. At the same time, generic drugs predominate in the market structure in 2019, accounting for more than 85% of the total number of packs sold, the cost of which amounted to about 60% of the total sales. Consequently, on the Russian pharmaceutical market, there is a tendency towards active distribution of generic drugs of domestic origin, which is due to their price advantage compared to original imported drugs, which are expensive and have problems with implementation under conditions of economic sanctions.

Evaluation of water productivity with three rice genotypes under different irrigation regimes and nitrogen fertilizer treatments in Rasht, northern Iran*

AbstractThis study investigates the water productivity of three rice genotypes in physical, economic and virtual water terms through different irrigation and fertilizer treatments. The experiment was conducted in 2017 and 2018 in split plot designs based on a randomized complete block design with three replications. The main factors include irrigation regimes: flood irrigation of I1 and alternate irrigation treatments of I2, I3 and I4 that involve alternate irrigation with irrigation intervals of 7, 14 and 21 days, respectively. The subfactors include different rice genotypes at three levels of certified local Hashemi, M5 and M12 genotypes at three levels of nitrogen fertilizer of 60, 80 and 100 kg N/ha1. Results showed that the certified Hashemi variety with the 7‐day irrigation interval and 100 kg N/ha1; treatment showed satisfactory physical water productivity (being 1.41 and 1.01 kg/m3 in 2017 and 2018, respectively), and also the highest net benefit per drop (being 31 200 and 29 800 rials/m3 in 2017 and 2018, respectively). According to the results of this study, using alternate irrigation at the 7‐day irrigation interval would save 285 million m3 of water in the Sefidroud irrigation and drainage network.

Exciton\u2013phonon coupling strength in single-layer MoSe2 at room temperature

Single-layer transition metal dichalcogenides are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton–phonon coupling plays a key role in determining the (opto)electronic properties of these materials. However, the exciton–phonon coupling strength has not been measured at room temperature. Here, we use two-dimensional micro-spectroscopy to determine exciton–phonon coupling of single-layer MoSe2. We detect beating signals as a function of waiting time induced by the coupling between A excitons and A′1 optical phonons. Analysis of beating maps combined with simulations provides the exciton–phonon coupling. We get a Huang–Rhys factor ~1, larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure exciton–phonon coupling also in other heterogeneous semiconducting systems, with a spatial resolution ~260 nm, and provides design-relevant parameters for the development of optoelectronic devices.

A locally anisotropic regularity criterion for the Navier–Stokes equation in terms of vorticity

In this paper, we will prove a regularity criterion that guarantees solutions of the Navier–Stokes equation must remain smooth so long as the vorticity restricted to a plane remains bounded in the scale critical space L t 4 L x 2 L^4_t L^2_x , where the plane may vary in space and time as long as the gradient of the unit vector orthogonal to the plane remains bounded. This extends previous work by Chae and Choe that guaranteed that solutions of the Navier–Stokes equation must remain smooth as long as the vorticity restricted to a fixed plane remains bounded in a family of scale critical spaces. This regularity criterion also can be seen as interpolating between Chae and Choe’s regularity criterion in terms of two vorticity components and Beirão da Veiga and Berselli’s regularity criterion in terms of the gradient of vorticity direction. In physical terms, this regularity criterion is consistent with key aspects of the Kolmogorov theory of turbulence, because it requires that finite-time blowup for solutions of the Navier–Stokes equation must be fully three dimensional at all length scales.

Energy and electron drift time measurements in a pixel CCI TlBr detector with 1.3 MeV prompt-gammas

Assessing the position of the Bragg peak (BP) in hadron radiotherapy utilizing prompt-gamma imaging (PGI) presents many challenges in terms of detector physics. Gamma detectors with the capability of extracting the best energy, timing, and spatial information from each gamma interaction, as well as with high detection efficiency and count rate performance, are needed for this application. In this work we present the characterization of a pixel Čerenkov charge induction (CCI) thallium bromide (TlBr) detector in terms of energy and and electron drift time for its potential use in PGI. The CCI TlBr detector had dimensions of 4 × 4 × 5 mm3 and one of its electrodes was segmented in pixels with 1.7 mm pitch. A silicon photomultiplier (SiPM) was optically coupled to one of the faces of the TlBr slab to read out the Čerenkov light promptly emitted after the interaction of a gamma ray. The detector was operated stand-alone and the 1.275 prompt gammas from a 22Na radioactive source were used for the study. The electron drift time was obtained by combining the Čerenkov and charge induction signals and then used as a measure of the depth of interaction. The electron mobility in TlBr was estimated as ∼27 cm2 V−1 s−1. Energy resolutions between 3.4% and 4.0% at 1.275 MeV were obtained after depth-correction. These values improved to 3.0%–3.3% when events with drift times of 3–6 μs were selected. These results show the potential of pixel CCI TlBr detectors to resolve gamma interactions in the detector with mm-like accuracy in 3D and with excellent energy resolution. Previous studies with CCI TlBr devices have shown a timing resolution of <400 ps full width at half maximum when detecting 511 keV gamma rays, therefore, the timing accuracy is expected to improve with the increased energy of the gamma rays in PGI. While other important detector characteristics such as count rate capability remain to be studied, results from this work combined with other preliminary data show pixel CCI detectors can simultaneously provide excellent energy, timing, and spatial resolution performance and are a very promising option for PGI in hadron therapy.

Гражданско-правовые особенности государственных и муниципальных контрактов, заключаемых с использованием электронно-цифровых средств

The article reflects the results of the analysis of legislation on the conclusion of state and municipal contracts using electronic and digital means and the practice of its application. It is noted that the conclusion of the contracts in question differs in physical and technological terms from those actions that are performed in the course of procurement without the use of electronic and digital means. However, the functional purpose of digital procurement remains unchanged. Therefore, neither special legislation on electronic digital signatures, nor the existence of requirements for the use of electronic digital means in the conclusion of state and municipal contracts change their written form. At the same time, the legal structure of their conclusion becomes more complex due to the requirement to specify a special record of accounting nature-the purchase identification code, which makes it possible to separate the contracts in question into an independent group along with transactions requiring state registration.

On the intrinsic dissipation and fracture fatigue entropy of metals

Determination of the fracture fatigue entropy (FFE) in materials requires a proper assessment of the intrinsic dissipation terms in the entropy production equation. In this paper, physical terms that contribute to internal friction and their implications on measuring FFE in metals are discussed. We show that internal friction is one of the terms in the intrinsic dissipation equation that cannot be neglected even for low-cycle fatigue tests (LCF). Relevant to measuring internal friction, we also introduce a technique to identify the fatigue limit of metals by measuring their damping value at different stress levels. Fatigue tests are performed to examine the validity of the proposed technique for two types of steels (SS 304 and SS 1018). By comparing our results with the available data in the literature, we find that the discrepancy is less than 10%. The temperature dependence of internal friction for SS304 specimens is also investigated. The result demonstrates a linear relationship and the existence of a peak.

Pre-service Science Teachers’ Awareness Towards Biodiversity

Bu araştırmada Fen Bilgisi öğretmen adaylarının biyoçeşitliliğe (biyolojik çeşitliliğe) yönelik farkındalıklarının incelenmesi amaçlanmıştır. Tarama modeli ile gerçekleştirilen araştırma 2019-2020 bahar yarıyılında bir devlet üniversitesinde Fen Bilgisi Eğitimi Anabilim Dalı dördüncü sınıfta öğrenim gören 57 öğretmen adayının gönüllü katılımı ile gerçekleştirilmiştir. Veri toplama aracı olarak araştırmacılar tarafından hazırlanan farkındalık formu kullanılmıştır. Bu formda yer alan altı soru ile Fen Bilgisi öğretmen adaylarından bir çevre kuruluşuna üye olup olmadıklarını, üye olmaları durumunda üye oldukları çevre kuruluşunun adını, biyoçeşitliliğin tanımını, biyoçeşitliliğin kapsamında yer alan canlıları, biyoçeşitliliği olumlu ve olumsuz yönde etkileyen faktörleri ve biyoçeşitliliğin faydalarını yazmaları istenmiştir. Elde edilen veriler içerik analizi ile çözümlenmiştir. Araştırma sonucunda Fen Bilgisi öğretmen adaylarının biyoçeşitliliğe yönelik farkındalıklarının yeterli olmadığı saptanmıştır. Öğretmen adayları biyoçeşitliliği tür, genetik, ekosistem ve ekolojik işlev çeşitliliği açısından ele alarak tanımlamış; biyoçeşitlilik kapsamında yer alan canlıları çoğunlukla tüm canlılar ile bitkiler ve hayvanlar olarak ifade etmişlerdir. Biyoçeşitliliği olumlu ve olumsuz yönde etkileyen faktörleri biyolojik, fiziki ve paleocoğrafik açıdan ele almışlardır. Biyoçeşitliliğin faydalarını ise ekoloji ve çevre sağlığı, besin ve gen kaynağı, ekonomi, tıp ve eczacılık açısından belirtmişlerdir. Araştırmada Fen Bilgisi öğretmen adaylarının yarısından fazlasının bir çevre kuruluşuna üye olmadığı görülmüştür. Fen Bilgisi öğretmen adaylarının biyoçeşitliliğe yönelik farkındalıklarının yeterli olmaması üzerinde bu durumun etkili olabileceği düşünülmektedir.

An Experiential Education Approach to Teaching the Mind-Body Problem

This article shows how the mind-body problem can be taught effectively via an experiential learning activity involving a couple of classroom props: a brick and a jar of ground coffee. By experiencing the physical properties of the brick (shape, weight, length, width) and contrasting them with the olfactory experience of coffee (seemingly dimensionless, weightless, etc.), students are introduced in a vivid way to the well-known difficulty of explaining the mental in physical terms. A brief overview of experiential learning theory and its connection to philosophy is also provided.

ЭКСПОРТ РАСТИТЕЛЬНОГО МАСЛА – ДРАЙВЕР ЭКОНОМИКИ АПК

The growth in the production of vegetable oils in recent years has created an opportunity to increase their exports. Exports in 2020 increased in all major groups of goods that Russia supplies abroad: grain, fat and oil, meat and dairy products, as well as food and processing industry products. Foreign supplies of fat and oil products increased by 12%, to 8.1 million tons, in physical terms and by 22%, to $ 5 billion, in monetary terms. The growth was provided primarily by the export of sunflower oil, of which 3.7 million tons (+ 19%) were shipped for $ 2.8 billion (+ 28%). Sales were particularly strong in the first half of 2020 after a record sunflower harvest in 2019. In 2020, foreign exchange earnings from the export of sunflower and rapeseed oils could have been higher, if not for the restrictive measures taken by the government. Foreign exchange earnings from the export of vegetable oils from Russia can be significantly increased by reducing the sale of oilseeds. At the same time, additional jobs can be created in Russia, and most importantly, the most valuable by-product (meal) will remain to ensure livestock breeding in the country. This requires the modernization of the material and technical base of the processing industry and the restoration of domestic seed production of oilseeds.

Agricultural development of the Kurgan region in modern conditions

Russia is one of the main producers of agricultural products, which is determined by the large size of its territory, natural conditions, land suitable for the production of agricultural products and other factors. Agriculture is a significant industry, the development of which is focused on both making a profit and ensuring food and national security. The leaders in the production of agricultural products in Russia are: the Krasnodar Krai, Rostov region, Belgorod region, Voronezh region. The Kurgan region is an industrial and agricultural region, for which agriculture is a system-forming branch of the economy, forming the agro-industrial market, food and economic security of the region. The agricultural degree has a significant impact on the standard of living and well-being of the population of the region: size and structure of food, per capita income, consumption of goods, and social standard of living. The article evaluates the dynamics of agricultural production development in the Kurgan region for 2015-2019. The dynamics of crop acreage, animal population, production of products by categories of farms and their implementation in physical terms are studied.

Thermodynamic Characterization of Planar Shapes and Curves, and the Query of Temperature in Black Holes

The purpose of this research is to characterize shapes in thermodynamic terms, namely, in terms of total energy, dissipative energy, entropy, and temperature. As case studies, polygons and some well-known curves were taken, and they were characterized using physical terms. The relation between entropy and curvature was elucidated, and the black hole surface gravity and temperature were criticized and reinterpreted from this point of view. Particular energy attributions were evaluated by comparing the position of any edge of a polygon (i.e. its angle with the horizontal axis) with a broken crystal surface. Energies of all edges were added up at all positions between 0˚ - 360˚. In regular polygons, the total energy decreases with the increase of the number of edges. Entropy increases in the reverse order, and the increase of the number of edges increases entropy. It implies that the circle has the lowest energy but the highest surface entropy. In curves (circle, sine-curve, spiral, and exponential curve), the total energy, dissipative energy, and entropy all depend on amplitude and also on specific variables. Black hole entropy expressed in terms of the surface area is a configurational entropy and not thermal entropy; therefore, it does not involve a varying temperature term. The surface gravity of a black hole is connected to acceleration and thus to curvature. To relate it with the temperature needs to be reinterpreted, because, surface gravity behaves like an attractive force not exactly like temperature. Hawking radiation is still possible, but the black hole does not get warmer as it evaporates. Material loss from the black hole gets faster as its radius decreases due to the curvature effect, i.e. by a mechanism similar to the Gibbs-Thomson effect.

ЗЕМЕЛЬНА РЕНТА ТА РЕНТНІ ВІДНОСИНИ: ЕВОЛЮЦІЯ ПОГЛЯДІВ І СУЧАСНЕ ЗМІСТОВНЕ НАПОВНЕННЯ

Introduction. The processes of transformation of the national economic system are accompanied by the aggravation of a number of problems. One of the most important is the problem of efficient use of land resources. The possibility of its solution is determined primarily by the level of organization and functioning of land-rent relations. Currently, rent, which is formed through the use of land and its resources, is considered only as a certain monetary income. There is no awareness that it is one of the most important material factors of expanded reproduction.The purpose of the scientific article is to systematize views on the essence of land rent and rent relations, to clarify the place of land rent in modern concepts of rent relations and to substantiate its role in the process of social reproduction.Results. The article substantiates the main provisions of modern concepts of rent relations and clarifies the place of land rent in their problems. The evolution of views on the interpretation of the essence of land rent and rent relations is revealed. The nature of land rent, preconditions of its origin and distribution, role in the process of social reproduction are determined. In modern conditions it is necessary to form a systematic vision of different types and subspecies of the general phenomenon of economic rent. It is also necessary to allocate land rent as an economic form of land ownership. Based on the modern interpretation of the general phenomenon of rent, it is advisable to show the place of land rent in the reproduction process. In comparison with wages, interest, income, land rent is the most controversial type of income in terms of its withdrawal and distribution. Land rent has features that distinguish it from other types of income. To determine land rent, its separation from economic rent, it is necessary to identify the distinctive features of land that are not inherent in other resources. They turn land rent into a special kind of income, not identical to wages, interest, profits, as well as royalties and other rental income. Distinctive features of the earth and other resources which make a single whole with the earth, are: 1) an origin not from human activity; 2) non-reproducibility (impossible to reproduce artificially); 3) quantitative limitations; 4) the ability not to wear out physically and not to grow old morally; 5) physical immobility (immobility); 6) the product of the earth can be formed both as a result of human activity and independently of it; 7) land is widely used in non-agricultural production as an area for mining, construction, placement of transport communications, etc .; 8) land is able to form or increase the amount of product without additional labor and therefore is able to provide as a surplus income natural rent (in physical terms); 9) the product of the land almost always needs further cultivation or leaves room for it - it always has the potential to create value added on its basis; 10) land by its nature has conditions for the social nature of ownership.Originality. The conceptual apparatus of rent relations is specified. It is proved that the concept of "rent payments", which is widely used, can not fully reflect the economic relations in the agro-industrial complex. The concepts of "rent withdrawals" or "rent redistribution" can be considered more adequate. This is due to the fact that withdrawals are made not only through the taxation mechanism. They are often carried out indirectly - through various market mechanisms.Conclusions. Land and its resources are gradually involved in the process of social reproduction, but the speed of such involvement has recently increased. The value of the product of land and land rent in the cost system increases to the same extent. Due to rent withdrawals and rent redistribution in the economic system are created favorable for production and consumption value ratios. Land rent in value terms can serve as a stabilizer. It can be removed where it is redundant and sent to where there is a distortion of exchange rates. Distortion of the foundations of rent relations does not allow to perform an important function of rent - to ensure rational relationships between agriculture and other areas of social production.

Steady state dynamic analysis and testing of an FSAE vehicle

The work proposes a method for the synthesis of chassis parameters for achieving specific steady state and transient characteristics of a vehicle. An approach that employs a set of static and dynamic tests coupled with vehicle dynamics simulation models is presented which provide a better insight into vehicle tuning and gaining insight into these dynamic test results. The testing procedures are divided into static and dynamic tests. Static tests focus on characterizing the vehicle's suspension and steering systems by employing a Kinematics and Compliance rig. These static tests are essential before conducting any dynamic test to make sure the dynamic tests cover the non-linearity caused due to these. The static test is followed by the dynamic tests along with MATLAB simulations to gain initial understanding of what to expect from these test procedures. A steady state test is carried out to compute the understeer gradient of the vehicle which in physical terms can be translated to how comfortable the vehicle is to drive over a range of lateral acceleration. The simulation involves the static test data which completes the metric estimation at both simulation level as well as from the raw data. This steady state test is followed by a transient test which employs tools from control theory to make it easier to analyze the vehicle and tune it for specific transient response times which are favorable to the driver. These dynamic test outputs can now be used for the synthesis of vehicle parameters. The parameter sensitivity of metrics from the simulations can be used to fine tune the vehicle during testing sessions in a more intuitive and effective manner.

ОЦЕНКА ТЕХНИКО-ЭКОНОМИЧЕСКОГО УРОВНЯ ТЕХНОЛОГИЧЕСКОГО ОБОРУДОВАНИЯ ДЛЯ ОБРАБОТКИ ГИЛЬЗ ЦИЛИНДРОВ

he production of high-quality repaired engines is possible only with the right selection of technological equipment. The issues of the processing quality on honing machines rank first in the repair production, since the reliability of engines depends on the processing quality of cylinder liners. It is revealed that for a clear understanding of the feasibility of using old and choosing new technological equipment, it is necessary to evaluate it from the standpoint of an integral quality indicator. As a basic model for assessing the quality of technological equipment, use is made of the cost method. According to it, the cost index of quality as the value inverse to the integral indicator of product quality is formed for evaluating machines. It is determined by the value of the unit cost of processing one part calculated in cost form by groups of resource intensity indicators multiplied by the corresponding resource prices. Each cost group is the product of the resource price by its specific consumption in physical terms, resulting in a cost index of quality. For honing machines used for processing cylinder liners, a relationship was determined to analyze the cost index of quality. This index includes four basic elements – the indicators of material intensity, labor intensity, energy intensity of machinery and the material intensity of the inputs used in the technological process. The evaluation of the quality of machines has revealed that purchasing new equipment is economically feasible as technical and economic level of new machines exceeds the base level due to increased productivity, reduced energy consumption and unit cost. It is most advisable to use the ROBBI SET150-L machine (Italy) from among the new ones, since its integral quality indicator is significantly higher than its analogues. From among the old ones, NAGEL VS8-50 (Germany) should be recommended, while domestic machines should be replaced due to their low efficiency.

THE RESTORATION AND REFUNCTIONING PROPOSAL OF ÖZDOĞANLAR MANSION IN SİVAS

Özdoğanlar residence, in Sivas Province, Merkez District, Akdeğirmen neighbourhood; is one of the few original housing examples in the historical city centre which is important to protect together with the traditional houses in its vicinity. Purpose: To make the restoration decisions of the abandoned building, which has entered a period of rapid degradation due to natural and human-induced effects, and which is in danger of collapse, and to present conservation and usage recommendations. Method: Within the scope of this study, the plan setup, construction system, original elements and problems of the building are defined; its current situation, changes and deteriorations were documented and dated and related restitution proposals were presented; The potential and needs of the house and its immediate surroundings have been evaluated. Findings: It has been determined that the Özdoğanlar residence has lost its original features day by day as a result of intense exposure to atmospheric conditions due to being out of use, the additions and removals made by the former users on time, and the looting by groups prone to Vandalism. Suggestions for the solution of the identified problems of the building were determined in chemical and physical terms. These data were obtained by researching the original plan scheme, space and architectural elements of the building. Result: Özdoğanlar House, which is a qualified traditional house example with its original plan scheme and architectural features, has been documented. A restoration proposal that will preserve the original characteristics of the building was prepared and presented.

Violation of the lexical norm in the modern newspaper language

This article assesses language as a key component in the development of media linguistics. Given that the main purpose of “language criticism” is to identify and correct shortcomings, it is im-portant to critically assess both incorrect and correct options when dealing with language pro-ducts. The paper puts special emphasis on the language of the media which needs to be normative. The author explores the development of newspaper language in terms of lexical norm vio la tion in the 1920s and 1930s. This article discusses equivalents to non-normative use of words in the daily all-Ukrainian newspaper The Day, one of the most popular publications in the ranking of national media. On the basis of various monolingual dictionaries of Standard Ukrainian and bilingual Russian-Ukrainian dictionaries, the author analyzes the use of tokens/lexemes napruha ‘voltage’, vidbyvaty‘to reflect’, pizniše ‘later’ in newspaper publications. Thus, the word napruha ‘voltage’ should be used only as a technical, physical term; in other cases it is napružennia ‘tension’. When it comes to expression, reproduction, an embodiment in images, it is correct to use vidobražaty ‘to reflect, re-mind of’, viddzerkaluvaty ‘to mirror’ but not vidbyvaty ‘to reflect’. As for pizniše ‘later’, it indicates a period after the time mentioned. It differs in its lexical meaning from zhodom ‘afterwards’ (some time after something) and potim ‘later’ (happening after something, following in time or space, no clear indication of time). Keywords: non-normative use, lexeme, dictionaries, newspaper publications.

Gasochromic properties of thin film oxides in terms of surface physics

A novel gasochromism phenomenon is descried using thin films of the ZnO, NiO and WO3 oxide semiconductors under hydrogen exposition, exhibiting rather advantageous properties than previously used fiber optic coating. The oxides were fabricated on glass substrates by RF Magnetron Sputtering technique. Structural and optical characterizations of the semiconductors were completed with XRD, Raman, SEM and optical absorption measurements. To investigate the optical response of these semiconductors to hydrogen gas, an optical gas sensor test system was prepared and programmed during the studies, using charged coupled device (CCD) signal processing. A nano-layer metal sensitizing of Pd and Pt up to 340% on the thin film surfaces of the various oxide samples of ZnO, NiO and WO3 have also been observed in the range of 450–850 nm wave lengths, covering the VIS-IR range. Overall optical response is rather amphoteric for n and p-type materials, having correlation with the resistivity responses. Present applications of the obtained devices on the hydrogen sensing up to low concentrations of 200 ppm, with relatively low response times around 70 s and that of recovery around 200 s, even at the room temperature execution. It is predicted that this extraordinary situation can also be used for various other applications such as smart windows and solar technology, especially in air and oxygen exposure.

Looking at the Physics of What a Quark Star-Black Hole Binary Would Create in Terms of GW Signals and New Physics

A quark star, black hole pairing as a would-be Gravitational wave generator is brought up. Quark stars are, anyway, likely to be black holes, above a certain mass limit, whereas a quark star in itself obey thermodynamic “laws” which in certain ways differ from the traditional black hole models. We list some of the probable consequences of such a binary, and make predictions as to certain GW phenomenon which will have observational consequences. i.e., a GW “change in energy” from a black hole—Quark star pair would likely be within 90% of that of comparatively massed black hole—black hole binary pair. The electromagnetic “profile” of the two cases would differ dramatically, and we conclude our inquiry with an open question if a generalized uncertainty principle could play a role in comparing the 7th and 8th equations of our presentation.

Insights on the non-linear solution of Munk's ocean circulation theory from a rotating tank experiment

Abstract At age 101, Walter Munk passed away in 2019. His groundbreaking discoveries will still guide and amaze oceanography students for years to come. Here, we perceive patterns in rotating tank with Munk's circulation theory aided by a Lagrangian particles tracking algorithm and numerical modeling. From information captured by video, we track the trajectories of drifters, and then objectively mapped the streamfunction to obtain the mean circulation pattern. We were able to reproduce the wind-forced anticyclonic and asymmetric gyre, including the western boundary intensification and its retroflection. The latter phenomenon was predicted by the non-linear version of Munk's model and observed in real subtropical gyres as small recirculation regions. We have configured two numerical model simulations mimicking the physical experiment, with linear and non-linear terms. The comparison between the numerical and physical experiments confirmed the effect of non-linear distortion of the gyre. Geophysical fluid dynamics is often hard to visualize, and counter-intuitive in a rotating system. We present this set of experiments as a tool for oceanography teaching. Besides studying general ocean circulation theories and observations through practical examples, this experiment provides an opportunity to develop basic image processing and geophysical modelling skills.