External Zone Research Articles

Armalcolite-bearing island arc plagiolherzolites and olivine gabbro-norite-dolerites of the area of Balaklava, Crimea

Armalcolite (Mg,Fe)Ti2O5 is characteristic mineral of titanian basalts of the Moon, as well as lamproites, other alkaline magmatic Earth rocks, impactites and other formations. It is widely represented in island-arc low-alkaline plagiolherzolites and olivine gabbro-norite-dolerites of the Early-Bajocian Pervomaysk–Ayu-Dag complex of mesozoids in Rocky Crimea, specifically, in the littoral Balaklava cliffs near Sevastopol. Crystals of cumulative Mg-olivine contain the inclusions of alumomagnesiochromite and Mg alumochromite in the center and the inclusions of alumochromite partly replaced by chromespinels of the 2nd generation (Ti-Al ferrychromite and chrometitanomagnetite) in the external zones. Chromespinels of the 1st generation are moderately chromic and ferrian (f = 4555), contain 8–14 mass.% Fe2O3 and up to 1,2% TiO2; that sharply distinguishes them from chromespinels of alpinotypes ultrabasic rocks. Chromespinels of the 2nd generation are more ferrian (f = 5875) and contain up to 26 mass.% Fe2O3, 2,5–9% TiO2 and up to 1,8% V2O3. The typical basic trend from ferrian alumomagnesiochromite to chrometitanomagnetite is characteristic for Balaklava chromespinels. Tabular armalcolite crystals are up to 0,60,2 mm included in intercumulus magnesian bronzite and augite, anorthite and bytownite. Balaklava armalcolite contains 63–66 mass.% TiO2, 6,9–8,4% MgO, 9,9–11,7% FeO, 13–18% Fe2O3, up to 1,5% Al2O3 and V2O3, up to 0,7% Cr2O3. The armalcolite formulae is (Mg0,38–0,45Fe2+0,30–0,34Fe3+0,36–0,49V0,04–0,05Al0–0,06Cr0–0,02Ti1,73–1,77)3O5; in minals, molar %: 38–45 MgTi2O5, 31–36 Fe2+Ti2O5, 23–27Fe3+2TiO5. Rare baddeleyite with 1,6–3,1% HfO2(ZrO2:HfO2 = 57–30, av. 44) and zirconolite associate with armalcolite. Zirconolite contains 4–6,5 mass.% Y2O3, 4–8% REE2O3, from traces up to 4,5% ThO2, <0,5% UO2, 0,7–1,4% HfO2 (ZrO2:HfO2 = 47–25, av. 38). The distribution of lanthanides in Balaklava zirconolite is Ce = Nd > Dy > Gd > Sm, Yb, Er, Lu, Tb > Pr. The zirconolite formulae is (Ca0,7Y0,2REE0,1)Zr(Ti1,6Fe2+0,3Fe3+0,1)2O7. The recent formations are ilmenite-I with 5–8 mass.% MgO and 0,3–0,6% MnO, titanomagnetite, hydroxyl-fluorapatite, ilmenite-II, poor in Mg and enriched in Mn. Armalcolite is partly replaced by ilmenite-II. Perhaps, an existence and preservation of armalcolite and zirconolite within the near surface basic intrusions of the Crimean Mountains is caused by poor development of late magmatic processes.

Site evaluation for nuclear power plants – The practices

Selection of appropriate site and robust site evaluation have significant impact on the design, construction and operation of nuclear power plant (NPP) in meeting the nuclear safety requirements following the concept of Defense-in-Depth (DID). The site evaluation is a continuing process over the life cycle activities of an NPP including its site selection. The objective of site evaluation is that the site-plant interaction does not cause radiation exposure to the public and environment beyond a threshold value during both normal operation and accident situations. The site evaluation is a multi-task process consisting of site characterization, derivation of design basis of external natural and human induced events and examination of implementation of emergency management planning. Radiological impact assessment and environmental (non-radiological) impact assessment are part of investigations of the suitability of site. The subject is challenging as site evaluation is not confined to technical activities only; it needs administrative and social input. All these lead to different countries having different practices in defining site and its external zones, and for site evaluation activities at different stages of life cycle, management system, and regulatory interfaces. Effort is made in this paper to outline the state-of-the-practice of site evaluation for nuclear power plants. The site evaluation processes of three countries USA, France and India are reviewed and summarized. The summary is then integrated with the requirements and guidance on this subject given in IAEA safety standard (IAEA, 2016) and insights gained from the NEA/CNRA document (NEA/CNRA, 2010). Experience gained from recent accidents/incidents of nuclear power plant is also studied and suitably incorporated in this review work.

Tanycytes and the Control of Thyrotropin-Releasing Hormone Flux Into Portal Capillaries.

Central and peripheral mechanisms that modulate energy intake, partition and expenditure determine energy homeostasis. Thyroid hormones (TH) regulate energy expenditure through the control of basal metabolic rate and thermogenesis; they also modulate food intake. TH concentrations are regulated by the hypothalamus-pituitary-thyroid (HPT) axis, and by transport and metabolism in blood and target tissues. In mammals, hypophysiotropic thyrotropin-releasing hormone (TRH) neurons of the paraventricular nucleus of the hypothalamus integrate energy-related information. They project to the external zone of the median eminence (ME), a brain circumventricular organ rich in neuron terminal varicosities and buttons, tanycytes, other glial cells and capillaries. These capillary vessels form a portal system that links the base of the hypothalamus with the anterior pituitary. Tanycytes of the medio-basal hypothalamus express a repertoire of proteins involved in transport, sensing, and metabolism of TH; among them is type 2 deiodinase, a source of 3,3′,5-triiodo-L-thyronine necessary for negative feedback on TRH neurons. Tanycytes subtypes are distinguished by position and phenotype. The end-feet of β2-tanycytes intermingle with TRH varicosities and terminals in the external layer of the ME and terminate close to the ME capillaries. Besides type 2 deiodinase, β2-tanycytes express the TRH-degrading ectoenzyme (TRH-DE); this enzyme likely controls the amount of TRH entering portal vessels. TRH-DE is rapidly upregulated by TH, contributing to TH negative feedback on HPT axis. Alterations in energy balance also regulate the expression and activity of TRH-DE in the ME, making β2-tanycytes a hub for energy-related regulation of HPT axis activity. β2-tanycytes also express TRH-R1, which mediates positive effects of TRH on TRH-DE activity and the size of β2-tanycyte end-feet contacts with the basal lamina adjacent to ME capillaries. These end-feet associations with ME capillaries, and TRH-DE activity, appear to coordinately control HPT axis activity. Thus, down-stream of neuronal control of TRH release by action potentials arrival in the external layer of the median eminence, imbricated intercellular processes may coordinate the flux of TRH into the portal capillaries. In conclusion, β2-tanycytes appear as a critical cellular element for the somatic and post-secretory control of TRH flux into portal vessels, and HPT axis regulation in mammals.

Characterization of apples (Granny Smith) dried in industrial equipment and the relationship with drying mechanisms

Abstract The aim of this paper was to study the effect of a convective continuum industrial drying process on microstructural changes, bulk density, and total soluble solids of apple slices (inner and surface) and their relationship with drying mechanisms. Experiments were carried out with a conveyor dryer (Proctor & Schwartz, model k97058) that includes three continuum stages (A, B, and C). Apple samples (Granny Smith) were taken in accordance with drying equipment feasibility; raw materials were obtained at dryer input, partially dried apple samples between stages A and B and between stages B and C, and dried apple samples were obtained at dryer output. Moisture content and bulk density were determined for all apple samples, and total soluble solids content of whole apple samples and their external surface were determined. Some apple samples were rapidly frozen (−195.8 °C) for observation by scanning electron microscopy (SEM). Results showed the presence of two possible drying mechanisms: evaporation at the beginning of the drying process (stage A) and liquid water transport in stages B and C. A remarkable difference in the total soluble solids content and microstructure between external and internal zones of apple samples was experimentally determined. More studies at industrial scale are needed to improve the final quality of dried products.

Hot radial shear rolling and rotary forging of metastable beta Ti-18Zr-14Nb (at. %) alloy for bone implants: Microstructure, texture and functional properties

In this study, a novel combination of hot radial shear rolling and rotary forging operations was applied to Ti-18Zr-14Nb shape memory alloy with the objective of forming a long-length bar stock for bone implants fabrication. Evolutions of the microstructure, texture, mechanical properties, and functional fatigue behavior of the fabricated bar stock were monitored along the technological workflow. Radial shear rolling leads to the formation of a strongly heterogeneous microstructure along the cross-section of the deformed bar stock. In the external zone of the bar stock, in the extraction direction, a dynamically recrystallized structure (d ≈ 25 μm) with the <111> fiber texture is formed. As we approach the central area, the grain size increases to d ≈ 130 μm and the texture becomes random. After the subsequent rotary forging, the alloy exhibits a dynamically polygonized substructure of β-phase with a more homogeneous across-the-section grain size distribution (d ≈ 34–43 μm) and a weak <212> texture. In this structural state, the alloy offers the following set of properties, which make it suitable for implant applications: low Young's modulus (E = 41 GPa), high value of elastic strain (e = 1.11%), and superior functional fatigue behavior with a low level of accumulated strain. In the forged condition, a calculated limit for the recovery strain for a weak <212> texture is about 5%.

Genesis and metallogenetic setting of the polymetallic barite-sulphide deposit, Bobija, Western Serbia

The polymetallic Bobija ore deposit in Western Serbia is located at the southwestern edge of the Jadar Block, a distal part of the passive continental margin of Adria. The sulphide mineralization consists of fine-grained pyrite, sphalerite, galena and tetrahedrite, and is associated with abundant barite. The deposit is stratabound and hosted by a Triassic sedimentary sequence. A feeder zone is present in the immediate footwall of the ore mineralization. The volcano-sedimentary succession in the uppermost strata comprises coherent lavas and volcaniclastic sediments. They were investigated for the bulk rock composition and the zircons were subjected to U–Pb dating. Analysed zircons deliver an upper age limit of 243.1 ± 1.3 Ma. Sphalerite from the sulphide mineralization was investigated for its trace element content and pyrite and barite for their sulphur isotope composition. Sphalerite geothermometry indicates ore-bearing fluid temperatures of 152–179 °C. A negative δ34S value of − 6.3‰ in pyrite indicates a sulphur source from a partially reduced reservoir. The new data confirm a previously inferred Triassic age for the Bobija deposit and underline the importance of the prevalent rift regime for ore formation. We propose that the sediment-hosted Bobija deposit should be classified as a clastic-dominated, rift-related Pb–Zn deposit. Given the tectonic setting and temperature constraints, the hydrothermal processes are comparable to deposits classically referred to as sedimentary exhalative (SEDEX). This is in a good agreement with similar deposits occurring in Central Bosnia. These similarities reveal links between ore deposit formation and geodynamic evolution in the Balkan Peninsula, underlining the common geological evolution of the more external zones of the Dinarides and the Jadar Block.

Electron backscatter diffraction (EBSD) analysis of maniraptoran eggshells with important implications for microstructural and taphonomic interpretations

AbstractElectron backscatter diffraction (EBSD) is a useful tool for gathering crystallographic information from carbonate biominerals because it maps out the orientation of crystal grains very precisely. EBSD has become popular in invertebrate palaeontology but its application in vertebrate palaeontology remains limited. However, the study of fossil eggshells is a field where EBSD has wide potential applicability and provides a quantitative approach to fossil eggshell research as well as new qualitative data. Here we analyse fossil and extant maniraptoran dinosaur eggshells using EBSD analysis emphasizing four different aspects. The mapping imaging clarifies previously ambiguous characters such as squamatic ultrastructure and allows a more objective evaluation of avian and non‐avian maniraptoran eggshell. In particular, our results imply that the presence of an external zone in the manirpatoran eggshell is not diagnostic of avian eggshell. EBSD analysis can be also used for differentiating true pore canals from cracks in the eggshell radial section, thereby determining the biological genuineness or otherwise of a pore‐like structure. Finally, the misorientation angle distribution of the material shows a clear dichotomy that may reflect reproductive brooding strategy, although further studies on contact incubation of palaeognaths and neognaths are needed to confirm this.

Characteristics of swirling and precessing flows generated by multiple confined jets

An experimental study is reported of the interaction between multiple isothermal jets within a cylindrical chamber under conditions relevant to a wide range of engineering applications, including the confined swirl combustors, industrial mixers, and concentrated solar thermal devices. The particle image velocimetry technique was used to investigate the swirling and precessing flows generated with four rotationally symmetric inlet pipes at a fixed nozzle Reynolds number of ReD = 10 500 for two configurations of swirl angle (5° and 15°) and two alternative tilt angles (25° and 45°). The measurements reveal three distinctive rotational flow patterns within the external recirculation zone (ERZ) and the central recirculation zone (CRZ) for these configurations. It was found that the mean and root-mean-square flow characteristics of the swirl within the chamber depend strongly on the relative significance of the ERZ and CRZ, with the swirling velocity being higher in the CRZ than that in the ERZ. A precessing vortex core was identified for all experimental conditions considered here, although its significance was less for the cases with a dominant CRZ.

A competition between the contour and hatching zones on the high cycle fatigue behaviour of a 316L stainless steel: Analyzed using X-ray computed tomography

Metal powder bed fusion techniques can be used to build parts with complex internal and external geometries. Process parameters are optimized in order to obtain parts with low surface roughness and porosity, while maintaining a high productivity rate. The goal of this work is to quantify the sensitivity to internal and surface defects on the fatigue endurance of additively manufactured metallic parts. 316L Stainless Steel samples were fabricated through powder bed fusion using identical contour parameters, but three different hatching strategies were applied by varying the scanning speeds in the internal portions of the parts. Samples were subsequently mirror-polished to smooth the rough as-built surface. X-ray computed tomography analysis revealed several defect populations in samples from all three parametric sets due to lack of fusion in the bulk, with a nearly fully dense external “shell”. High cycle fatigue tests at R = 0.1 were then performed on the specimens and combined with the X-ray computed tomography scans, helping to identify the largest and the critical defect size at which crack initiation occurred. Most fatigue failures initiated within the external contour zone for small (<100 μm) defects, even when larger (>200 μm) lack of fusion defects were widely present below the surface. It was determined that the high porosity (1% in volume or above 5% in area at some fabricated layers) observed in the bulk of parts manufactured with high scanning speeds had little impact on the fatigue limit of the material.

SOME DATA ON BIOLOGY AND FISHERY OF ICEFISH SALANGICHTHYS MICRODON IN PETER THE GREAT BAY (JAPAN SEA)

Within Peter the Great Bay, common icefish Salangichthys microdon forms commercially valuable aggregations in two areas of the Amur Bay and in one area of the Ussuri Bay. It spawns in the internal estuaries of the rivers entered to the bays and in the external estuarine zones in the tops of the bays, mostly on small pebble grounds from late April to late May and feeds in the bays waters. Data on its size and weight composition were obtained in 2017–2018 both from the Amur Bay (for spawning period) and from the Ussuri Bay (for feeding period). During the spawning (on May 6 and May 18), the body length was 59–90 mm, on average 74.9 mm, and the weight was about 750 mg; sex ratio males : females was 1.0 : 0.8. During the feeding, the average body length was 66.8 mm.

Haliplidae, Noteridae, Dytiscidae (Coleoptera) from Gabon (12th part). Moukalaba - Doudou National Park (mission 2014) and in an area North of the Park

This work concerns the Coleoptera Hydradephaga collected in several sites of the Moukalaba - Doudou National Park and in external zone North of the Park. In the Park 107 species have been collected, 109 species in external zone. The Authors describe 7 new species of Dytiscidae: Hydrovatus rigatoi n. sp. (confossus group) chiefly distinguishable for shape of penis; Bidessus mboyei n. sp. (sharpi group, ovoideus subgroup) close to B. ovoideus Régimbart, 1895 and B. seydeli Biström, 1885, distinguishable for smaller size and for shape of penis; Clypeodytes acutipenis n. sp. close to C. densepunctatus Biström, 1988, distinguishable for apex of penis clearly pointed; Laccophilus sinuosipenis n. sp. (deceptor group) close to L. bizonatus Régimbart, 1895, distinguishable for sinuous shape of penis; Laccophilus cianferonii n. sp. (deceptor group) close to L. bilardoi Pederzani and Rocchi, 1982, chiefly distinguishable for shape of penis; Copelatus bapounouensis n. sp. (erichsonii group, atrosulcatus subgroup) close to C. ellai Bilardo and Rocchi, 1995, chiefly distinguishable for shape of penis; Copelatus gigas n. sp. (erichsonii group, vigintisulcatus subgroup) close to C. fasciatus Bilardo and Rocchi, 1995, chiefly distinguishable for large size and for shape of penis. Moreover some observations concerning the ecology and data about the distribution of several species are provided.

Salt Distribution in Raw Sheep Milk Cheese during Ripening and the Effect on Proteolysis and Lipolysis.

The salt distribution process in artisanal sheep cheese with an innovative shape of eight lobes was investigated. The cheese was subjected to two brining conditions: 24 h with brine at 16°Baumé and 12 h at 22°Baumé. The chemical composition (pH, water activity, dry matter, fat, and protein content), proteolysis (nitrogen fractions and free amino acids), and lipolysis (free fatty acids) were evaluated in two sampling zones (internal and external) at 1, 15, 30, 60, 90, 120, 180, and 240 days of ripening. The whole cheese reached a homogeneous salt distribution at 180 days of ripening. Brining conditions did not have an influence on the rate of salt penetration, but on the final sodium chloride (NaCl) content. Cheese with higher salt content (3.0%) showed increased proteolysis and lipolysis as compared to cheese with lower salt content (2.2%). Proteolysis index and total free fatty acids did not differ significantly (p > 0.05) between internal and external zones of cheese. It is suggested that producers start marketing this artisanal cheese at 6 months of ripening, when it has uniform composition and salt distribution.

Mesencephalic origin of the inferior lobe in zebrafish

BackgroundAlthough the overall brain organization is shared in vertebrates, there are significant differences within subregions among different groups, notably between Sarcopterygii (lobe-finned fish) and Actinopterygii (ray-finned fish). Recent comparative studies focusing on the ventricular morphology have revealed a large diversity of the hypothalamus. Here, we study the development of the inferior lobe (IL), a prominent structure forming a bump on the ventral surface of the teleost brain. Based on its position, IL has been thought to be part of the hypothalamus (therefore forebrain).ResultsTaking advantage of genetic lineage-tracing techniques in zebrafish, we reveal that cells originating from her5-expressing progenitors in the midbrain-hindbrain boundary (MHB) participate in the formation of a large part of the IL. 3D visualization demonstrated how IL develops in relation to the ventricular system. We found that IL is constituted by two developmental components: the periventricular zone of hypothalamic origin and the external zone of mesencephalic origin. The mesencephalic external zone grows progressively until adulthood by adding new cells throughout development.ConclusionOur results disprove a homology between the IL and the mammalian lateral hypothalamus. We suggest that the IL is likely to be involved in multimodal sensory integration rather than feeding motivation. The teleost brain is not a simpler version of the mammalian brain, and our study highlights the evolutionary plasticity of the brain which gives rise to novel structures.

A critical fault detection analysis & fault time in a UPFC transmission line

This paper discusses a critical study of fault detection and fault time analysis in a Unified Power Flow Controller (UPFC) transmission line. Here the Discrete Wavelet Transform (DWT) and Discrete Fourier Transform (DFT) approach are used for processing the faulty current signal to obtain fundamental current signal. The extracted fault current signals from the current transformer are fed to DWT and DFT approach for computing spectral energy (SE). The differential spectral energy (DSE) of phase currents are evaluated by taking the difference of SE obtained at sending and receiving end. The DSE is the key factor for deciding the fault in any of the phase or not. The Daubechy mother wavelet (db4) is used here because of its high accuracy of detection with less processing time. The novelty of the scheme is that it can accurately detect the critical fault variation of the line. Number of simulations are validated at the extreme condition of the line and compared to other conventional existing scheme. Multi-phase fault in double circuit line, CT saturation, UPFC operating condition (series voltage and angle), UPFC location and wind speed variation including wind farm simulation are validated to verify the performance of the scheme. The advantages of the scheme is that it works effectively to detect the fault at any stage of critical condition of the line and fault detection time remains within 20 msec (less than one cycle period). This scheme protects both internal and external zone including parameter variation of the line.

Geochemistry of the Monte Filau orthogneiss (SW Sardinia, Italy): insight into the geodynamic setting of Ordovician felsic magmatism in the N/NE Gondwana margin

The Mt. Filau orthogneiss is an Ordovician orthogneiss outcropping in the External zone of SW Sardinia chain. It consists of dark, biotite-rich facies, a leucocratic coarse-grained facies and a leucocratic fine-grained facies with igneous andalusite. Coarse- and fine-grained leucocratic orthogneiss have comparable major elementcontents, being slightly enriched in SiO2 and depleted in Fe2O3, MgO, TiO2 and CaO as compared to the biotite-bearing orthogneiss. Bt-bearing orthogneiss shows higher Sr and Ba concentrations than leucocratic ones, whereas Rb content is higher in leucocratic orthogneiss as compared to the Bt-bearing ones. Zr content shows a progressive decrease from biotite-bearing orthogneiss, coarse-grained leucocratic ones, to fine-grained orthogneiss. In the spider diagram the Mt. Filau orthogneiss shows the typical signature of calc-alkaline rocks, with negative anomalies of Ba, Nb, Sr and Ti, and positive anomalies in U, K. REE patterns of Bt-bearing and coarse-grained leucocratic orthogneisses are characterized by a moderate LREE fractionation, flat HREE and negative Eu anomaly. Fine-grained leucocratic orthogneiss shows flatter patterns, stronger Eu anomalies and slight HREE enrichment. The geochemical features suggest a clear evolution trend, from the less evolved Bt-bearing orthogneiss to the more differentiated fine-grained leucocratic orthogneisses which likely represent aplite bodies deriving from the most acidic residual melt. Selected trace and REE elements of Mt. Filau are compared with other Ordovician orthogneiss outcropping in the Axial zone of Sardinia Variscan belt. Besides, their geochemical features are also compared with metavolcanics of External and Nappe zone. The geochemical affinity of orthogneisses and metavolcanics from Variscan Sardinia, together with the geochronological data, allows to state a clear cogenetic relationship between the bodies belonging to the calc-alkaline Ordovician magmatic cycle. Our results suggest that the early Paleozoic basement of Sardinia might represents the witness of an early Paleozoic subduction-accretionary complex recording convergence along the N/NE Gondwana margin.

The contribution of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) to “Adria LithosPHere investigAtion (ALPHA)” active seismic experiment

During the winter 2012, from 20 January to 4 February, the German oceanographic FS METEOR cruise (M86/3) took place in the central-southern Adriatic Sea in the frame of “Adria LithosPHere InvestigAtion” (ALPHA [Kopp et al., 2013]). The primary goal of the project was high-resolution tomographic imaging of the crust and lithospheric mantle underneath the southern Adriatic Sea, the Apulia eastern margin and the external zone of the Dinaric thrust-belt by collecting offshore-onshore seismic data along three multi-fold wide-aperture profiles. The definition of reliable velocity models of the Adriatic lithosphere was considered crucial for a better understanding of the structure, fragmentation, geodynamic evolution, and seismotectonics of the Adria-Apulia microplates. The ALPHA Project was coordinated by Helmholtz Centre for Ocean Research Kiel, Germany (GEOMAR), former Leibniz Institute of Marine Sciences (German: Leibniz-Institut fur Meereswissenschaften, IFM-GEOMAR) and conducted in close cooperation with different European institutions of Germany, Albania, Croatia, Italy and Montenegro. The Istituto Nazionale di Geofisica Vulcanologia (INGV) participated by deploying land stations along two transects in the Apulia and Gargano Promontory to extend westwards the seismic profiles. The primary goal was to record shallow-to-deep seismic phases travelling along the transition between the Adriatic basin and the Apulia foreland. In this paper we present the field work related to the two Italian onshore transects, the recorded data, and the processing flow developed to highlight crustal and mantle refractions and wide-angle reflections.

TENDENCIES AND PROBLEMS OF THE TRANSPORT INFRASTRUCTURE OF THE CITY AGGLOMERATIONS (CASE-STUDY OF YEKATERINBURG, KAZAN AND PERM)

Transformation of urban transport infrastructure is one of the most dynamic city processes. Changes occur continuously and connect both with the technology and with the city development. For Russian cities, the most common trends that affected the transformation of the transport system at the turn of the 20th century were the growth in the number of personal transport and the active development of city agglomerations. In addition to the general features, there are specific features of changing public transport, street-road network in each city and agglomeration. Comparison of these changes, taking into account the global trends, allows you to draw conclusions and give practical suggestions that may be of interest for both management practices and the development of science. It is important to realize that the transport system of cities-nuclei of agglomerations is under pressure not only of traffic flows within urban displacements, but is an open system integrated into agglomeration processes. In the article, the transformation of the transport infrastructure of the Russian cities of Yekaterinburg, Kazan and Perm is considered by its two main components - public transport and the street-road network. The selected three cities are not only regional capitals, but also nuclei of monocentric agglomerations. The comparison is made in the context of individual urban areas: the historical core, the zone adjacent to the historical core, and the outer zone. The main method used is the peer review method. This is due to the fact that it is not always possible to obtain a complete set of data for a formalized assessment of the section of the zones identified by the authors that do not coincide with the administrative-territorial cities. Although, where possible, the results of peer review are supported by statistical data and calculations. Real changes are compared with the version, which the authors consider to be optimal at this stage and described using a special score scale. According to the results of the expert assessment, Kazan and Yekaterinburg took the leading positions. For Kazan is characterized by systematic activities to ensure the effective operation of public transport. The city occupies a leading place in Russia (excluding the capital) in terms of the number of corridors and the length of the allocated lanes for public transport. In the past five years, there has been a large-scale renovation of the park of trams, trolleybuses and buses in municipal ownership. Ekaterinburg stands out as an urban tram network, which maintains a system-forming role in most areas of the city. It continues to develop: a new site appeared within a large center in 2017, at various stages of discussion and implementation are plans to build lines in the micro-districts of the city's outer zone, and also (for the first time in Russia) - to two satellite cities in Yekaterinburg.. The relatively high quality of the track infrastructure, high-quality operation of the rolling stock of tram transport also influenced the increase in the score of the expert evaluation. The most problematic aspects in all cities are: Inadequate integration of electric trains into the urban transport system; the lack of systematic work with drivers of personal vehicles on their compliance with the interests of all residents when using courtyard territories; the lack of systematic and consistent measures to form multifunctional transport and transfer nodes on the border of zones adjacent to the historical core and external zones, the development of the street-road network in connection with the formation of these nodes. Solving these problems will allow to proceed to the intensive development of city agglomerations.

Long-distance and daily travel demand: integration of various travel markets and modelling approaches

Most travel demand models simplify the representation of trips from/to external zones. Despite the higher frequency of internal daily travel, long-distance travel cannot be neglected due to its high contribution to the travelled distance. In this paper we integrate two different models that represent those two travel segments. MITO is an agent-based model for travel demand implemented in the metropolitan area of Munich. DEMO is a macroscopic model that generates travel demand in Germany. DEMO is used to represent the external, long-distance travel from, to or through the MITO study area. DEMO demand is disaggregated and is jointly assigned with MITO trips using the transport model MATSim. The integration significantly improves the validation of the model against traffic counts and facilitates the simulation capabilities when the scenarios affect major roads.

Параметрическое исследование двух устойчивых форм горения разряда в холловском двигателе

In this paper the behavior of the integral parameters of the Hall thruster (thrust, specific thrust impulse) in two stable discharge modes were experimentally investigated. This modes significantly different from each other in anode efficiency. The studies were carried out on a laboratory model of Hall thruster with the external discharge zone with the middle-line diameter equal to 77 mm. The discharge voltage was in the range of 500-900 V and a gas flow rate was from 2.0 to 5 mg/s. The most striking differences between the discharge modes are the shape of the plasma plume and the value of the discharge current at practically identical input parameters of operation (gas flow rate, discharge voltage, magnetic field). It is shown that in the entire studied range of input parameters during the transition from the optimal mode (in terms of the efficiency) to the suboptimal mode the main integral characteristics of the thruster suddenly change: the discharge current increases by 10-30% with the simultaneous relative drop of thrust by 5-15% and efficiency by 20-40%. A detailed study of the structure of the anode efficiency showed that when the transition between modes occurs the electron current efficiency (the ratio of the ion current to the discharge current) abruptly changes, that is, the electronic conductivity in the discharge channel of the thruster changes too.

Wave Motion in an Ice Sheet with Crack under Uniformly Moving Load

The analytical solution to the problem of the behavior of an ice sheet with rectilinear crack under the action of uniformly moving rectangular external pressure zone simulating an air-cushion vehicle is obtained using the Wiener–Hopf technique. The ice cover is simulated by thin elastic semi-infinite plates of constant thickness floating on the surface of an incompressible fluid of finite depth. Two configurations are considered: 1) two semi-infinite plates with free edges (whose thicknesses can be different) are separated by a crack; 2) fluid is bounded by the vertical wall and the ice cover edge can be both free and frozen to the wall. In the case of the contact of plates of the same thickness, as well as in the presence of the wall, the solution is obtained in the explicit form. It is shown that in the case of the contact of identical plates with free edges, edge waveguide modes traveling along the crack are excited when the load moves at a supercritical speed. Both the wave forces acting on the moving body and the deflections of the plates are investigated for various values of the plate thicknesses and the load velocity in the sub- and supercritical regimes.