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Number of results: 93
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Abstract

This paper presents mathematical modelling and numerical analysis to evaluate entropy generation analysis (EGA) by considering pressure drop and second law efficiency based on thermodynamics for forced convection heat transfer in rectangular duct of a solar air heater with wire as artificial roughness in the form of arc shape geometry on the absorber plate. The investigation includes evaluations of entropy generation, entropy generation number, Bejan number and irreversibilities of roughened as well as smooth absorber plate solar air heaters to compare the relative performances. Furthermore, effects of various roughness parameters and operating parameters on entropy generation have also been investigated. Entropy generation and irreversibilities (exergy destroyed) has its minimum value at relative roughness height of 0.0422 and relative angle of attack of 0.33, which leads to the maximum exergetic efficiency. Entropy generation and exergy based analyses can be adopted for the evaluation of the overall performance of solar air heaters.

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Authors and Affiliations

Radha K. Prasad
Mukesh K. Sahu
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Abstract

The following paper provides an insight into application of the contemporary heuristic methods to graph coloring problem. Variety of algorithmic solutions for the Graph Coloring Problem (GCP) are discussed and recommendations for their implementation provided. The GCP is the NP-hard problem, aiming at finding the minimum number of colors for vertices in such a way that none of two adjacent vertices are marked with the same color. With the advent of modern processing units metaheuristic approaches to solve GCP were extended to discrete optimization here. To explain the phenomenon of these methods, a thorough survey of AI-based algorithms for GCP is provided, with the main differences between specific techniques pointed out.

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Authors and Affiliations

Adrian Bilski
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Abstract

This paper studies hydrodynamic and heat transfer performance of Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe in laminar flow regime using the computational fluid dynamic approach. A parametric study was carried out on the effect of Reynolds number (300– 1200), convergence index (0-3) and nanoparticle concentration (0–3%) on the both hydrodynamic and thermal fields. The results showed the pressure drop profile along the axial length of the converging pipes is parabolic compared to the downward straight profile obtained in a straight pipe. Furthermore, an increase in convergence index, Reynolds number and nanoparticle concentration were found to enhance convective heat transfer performance. Also, a new empirical model was developed to estimates the average Nusselt number as a function of aforementioned variables. Finally, the result of the thermohydraulic performance evaluation criterion showed that the usage of Bessel-like converging pipes is advantageous at a low Reynolds number.
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Authors and Affiliations

Chukwuka S. Iweka
1
Olatomide G. Fadodun
2

  1. Department of Mechanical Engineering, Delta State Polytechnic, Ozoro, P.M.B 5, Ozoro 334111, Delta State, Nigeria
  2. Centre for Energy Research and Development, Obafemi Awolowo University, Ile-Ife 220282, Osun State, Nigeria
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Abstract

Investigation for heat transfer behaviour of Al 2O 3 and CuO nano-fluid in helical coil heat exchangers was carried out in this study. The thermo-physical properties of the fluids have temperature dependent nature. The main emphasis was to depict the influence of nano-particle concentration by volume on the characteristics of temperature, rate of heat transfer and heat transfer coefficients (convective). In order to enhance efficiency, density and thermal conductivity are considered to be the most important variables. In comparison towater and for equal flowrate, the rate of heat transfer of nano-fluid increases conspicuously. Efficiency of the helical coil heat exchanger increased by 38.80%.
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Authors and Affiliations

Malik Parveez
1
Mohammad Hanief
2

  1. National Institute of Technology, Chemical Engineering Department, Srinagar, Jammu and Kashmir,190006, India
  2. National Institute of Technology, Mechacahnical Engineering Department, Srinagar, Jammu and Kashmir, 190006, India
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Abstract

In the region of the Admiralty Bay 12 nesting bird species were encountered of a total abundance of 40890 pairs and biomass amounting to about 395000 kg Three penguin species constituted 91.7% in abundance, their biomass constituting 98.7% of the whole community. Densities of abundance and biomass of adult birds in relation to the living area of penguins (i.e. 775 km2) ranged from 32.3 to 121.4 indiv. km-2 and from 115.1 to 4730 kg k m-2.

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Authors and Affiliations

Bolesław Jabłoński
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Abstract

The fundamental problem from the point of view of pipeline exploitation in KGHM Polska Miedz S.A. is the very high overwearing of the pipes used for the transport of tailings, as well as determining the time of trouble-free operation of pipe system components. Failures involve significant financial outlays, severe restrictions on operation and in some cases even stopping operation. For this reason, it is vital to monitor the condition of the transport systems, as well as to determine the permissible service life of the pipe sections, after which segments at risk should be replaced or turned over in order to extend their further operation. This paper focuses on the application of interval numbers to assess the durability of piping systems. The calculations were made using classical interval numbers by using code written in INTLAB libraries. The correctness of the solutions obtained was verified using the Monte Carlo method, assuming a uniform distribution of random variables.
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Authors and Affiliations

Iwona Duszyńska
1
ORCID: ORCID
Tomasz Krykowski
2
ORCID: ORCID
Paweł Stefanek
1
ORCID: ORCID
Joanna Bzówka
3
ORCID: ORCID

  1. KGHM Polska Miedz S.A., Oddział Zakład Hydrotechniczny, Lubin, Poland
  2. Silesian University of Technology, Faculty of Civil Engineering, Department of Mechanics and Bridges, Gliwice, Poland
  3. Silesian University of Technology, Faculty of Civil Engineering, Department of Geotechnics and Roads, Gliwice, Poland
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Abstract

As part of a general lexical system, urbanonymy reflects cultural phenomena in a broad sense. Alongside often discussed and well-studied lexical units, there are other urbanonyms that have been neglected by researchers for various reasons. Intra-city names containing numbers and figures belong to this neglected category. The aim of the study is to define the role of numbers and figures in Slavic urbanonymic systems. The research material is comprised of the contemporary urbanonymy of cities in Belarus, Russia, Poland and Bulgaria; toponymic dictionaries, electronic resources, tourist guides, maps and atlases have been used. The author demonstrates the shared and specific features of the numbers and figures used in the Belarusian urbanonymic system, as compared to that of Russia, Poland and Bulgaria. The symbolic meaning of these figures in the Slavic urbanomasticon is also discussed. I n spite of the existing differences in the use of names with a numerical component, their composition can be treated as a universal onomastic process. Street names containing figures are part of national culture, as they call to mind important national events or facts, both past and present. This helps individuals cultivate a personal sense of belonging to their native land, thus contributing to the preservation of tradition.
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Authors and Affiliations

Ганна Mезенка
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Abstract

The study presents the manners of determination of the Darcy friction factor λ for a homogenous hydromixture of alum sludge of varied hydration and temperature for the laminar flow zone. The rheological evaluation of the hydromixture as a viscoplastic body has been conducted with use of measurements of viscosity. The curves of flow were approximated with use of the generalized Vočadlo model. The Darcy friction factor λ of the pipeline was determined with use of the non-dimensional criterion λ(Regen) and λ(Re, He).
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Authors and Affiliations

Jan Kempiński
Marek M. Sozański
Zbysław Dymaczewski
Robert Świerzko
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Abstract

The paper describes tests intended to examine the occurrence of natural convection within the space occupied by 40×20 mm rectangular steel sections. Within these tests the bed of four layers of section was heated by the electric palate heater. Depending on the manner in which the heater was positioned, the tests were divided into two series. In the case of heating from above, the heat flowing through the bed is transferred only by conduction and radiation. When heating the bed from below, in addition to conduction and radiation, also a convective heat transfer will occur. Should this be the case, it will result in the intensification of the heat exchange. The results of measurements carried out have not demonstrated that the occurrence of any possible natural convection would influence the development of a temperature field in this type of charge.
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Authors and Affiliations

Rafał Wyczółkowski
Dorota Musiał
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Abstract

This paper analyses the real behaviour of the fluid in the channels of a three-end membrane module. The commonly accepted mathematical model of membrane separation of gas mixtures in such modules assumes a plug flow of fluid through the feed channel and perfect mixing in the permeate channel. This article discusses the admissibility of accepting such an assumption regarding the fluid behaviour in the permeate channel. Throughout analysis of the values of the Péclet number criterion, it has been demonstrated that in the industrial processes of membrane gas separation, the necessary conditions for the perfect mixing in the permeate channel are not met. Then, CFD simulations were performed in order to establish the real fluid behaviour in this channel. It was proved that in the permeate channel the fluid movement corresponds to the plug flow, with the concentration differences at both ends of the module being insignificant. In view of the observations made, the admissibility of concentration stability assumptions in the mathematical models for the permeate channel was discussed.

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Authors and Affiliations

Maciej Szwast
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Abstract

We used chromosome data to verify the taxonomic affiliation of specimens previously recognized as Brachyactis ciliata. All analyzed plants were diploids based on x = 7 (2n = 2x = 14), the basic number characteristic for Symphyotrichum ciliatum, allowing the examined species to be shifted from the genus Brachyactis to the genus Symphyotrichum sect. Conyzopsis. The chromosome number (2n = 2x = 14) for specimens of S. ciliatum from Poland is reported for the first time.

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Authors and Affiliations

Marta Tucharz
Agnieszka Nobis
Marcin Nobis
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Abstract

This article shows that Classical Arabic expresses verbal number. Arabic, of all the Semitic language family, meets the typological tests of the languages expressing verbal number. In addition, I will show that Classical Arabic provides a morphological verb form to express number. I will, however, show that for the form to express verbal number it requires a combination of morphological and semantic conditions. Without which the designated form does not express number, but expresses transitivity or the transfer of agency. These conditions are: form II must come from a root that has a form I, form I must be the transitive meaning of the root and the root must express an instant action. Form II, therefore, does not exclusively express number. Verbal number in Arabic is conditional. However, I will also propose that when form II verb expresses number, it does not express the transfer of agency.

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Authors and Affiliations

Muhammad Al-Sharkawi
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Abstract

Optimum truck numbers of an enterprise can be found by dividing the period of time passed between a departing truck after loading, the arrival at the dumping location, the arrival at the point of loading again and the average loading time parameters of a truck. The average loading time of the truck is directly associated with the bucket fill factor and cycle time of the excavator. While the bucket fill factor depends on the mechanical strength and the discontinuity characteristics of the rock, the cycle time is related to bucket volume, the strength and the discontinuity characteristics of the rock. In this study, two relations predicting the average cycle time of the bucket fill factor for both hydraulic and electric excavators is done by seven excavators with different bucket volumes, and mass characteristics of eight different rocks from a coal open pit mine. According to the above, the optimum truck number was developed.
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Bibliography

[1] S. Alarie, M. Gamache, Overview of Solution Strategies Used in Truck Dispatching Systems for Open Pit Mines. International Journal of Surface Mining Reclamation and Environment 16, 59-76 (2002).
[2] M. Beaulieu, M. Gamache, An Enumeration Algorithm for Solving the Fleet Management Problem in Underground Mines. Computers and Operations Research 33 (6), 1606-1624 (2006).
[3] A.C.M.M. Campelo, T. Marin, The Impact of Payload Truck Factor Use in Mine Performance Reports for an Open Pit Copper Mine in Brazil. REM – International Engineering Journal 71 (3), (2018). DOI: https://doi. org/10.1590/0370-44672017710189
[4] Y. Chang, Ren and S. Wang, Modelling and Optimizing an Open-Pit Truck Scheduling Problem. Discrete Dynamics in Nature and Society (745378), 8 (2015). DOI: https://doi.org/10.1155/2015/745378
[5] P. Chaowasakoo et al., Digitalization of Mine Operations Scenarios to Benefit in Real-Time Truck Dispatching. International Journal of Mining Science and Technology 27 (2), 229-236 (2017).
[6] Y . Choi et al., Multi-Criteria Evaluation and Least-Cost Path Analysis for Optimal Haulage Routing of Dump Trucks in Large Scale Open Pit Mines. International Journal of Geographical Information Science 23 (12), 1541- 1567 (2009).
[7] S.R. Dindarloo, M. Osanloo, S. Frimpong, A Stochastic Simulation Framework for Truck and Shovel Selection and Sizing in Open Pit Mines. Journal of the Southern African Institute of Mining and Metallurgy 115 (3), 209-219 (2015).
[8] S.G. Ercelebi, A. Bascetin, O ptimization of Shovel-Truck System for Surface Mining. Journal of The Southern African Institute of Mining and Metallurgy 109, 433-439 (2009).
[9] Y . Li, N.L. Hu ,G.Q. Li, Open-Pit Hauling Dispatching Optimization Based on Improved Pso Algorithm. China’s Mining Magazine 22 (4), 98-105 (2013).
[10] G . Liu, S. Chai, Optimizing Open-Pit Truck Route Based on Minimization of Time-Varying Transport Energy Consumption. Mathematical Problems in Engineering (687108) (2019). DOI: https://doi.org/10.1155/2019/6987108
[11] P.R. Michaud, J.Y. Blanchet, Establishing a Quantitative Relation Between Post Blast Fragmentation and Mine Productivity a Case Study. Proceedings of 5th International Symposium on Rock Fragmentation by Blasting 386- 396 (1996).
[12] A. Moradi Afrapoli, H. Askari-Nasab, Mining Fleet Management Systems: A Review of Models and Algorithms. International Journal of Mining Reclamation and Environmental 1-19 (2017).
[13] M. Munirathinam, J.C. Yingling, A Review of Computer-Based Truck Dispatching Strategies for Surface Mining Operations. International Journal of Surface Mining Reclamation and Environmental 8, 1-15 (1994).
[14] S.P. Singh, T. Yalcin, Effects of Muck Size Distribution on Scooping Operations. Proceedings of 28th Annual Conference on Explosives and Blasting Techniques 315-325 (2002).
[15] M. Sarı, P.J.A. Lever, Effect of Blasted Rock Particle Size on Excavation Machine Loading Performance. 20th International Mining Congress and Exhibition of Turkey. ISBN 978-9944-89-288-9 (2007).
[16] R .F. Subtil, D.M. Silva, J.C. Alves, 35th Apcom Symposium/ Wollongong, Nsw, 24-30 September, 765-777 (2011).
[17] L . Zhang, X. Xia, An Integer Programming Approach for Truck-Shovel Dispatching Problem in Open-Pit Mines. Energy Procedia 75, 1779-1784 (2015).
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Authors and Affiliations

Abdurrahman Tosun
1
ORCID: ORCID

  1. Dokuz Eylul University, Bergama, 35062, Izmir, Turkey
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Abstract

In Old English dual personal pronouns constituted a small but significant pocket of its inflectional morphology. Their disappearance in Middle English is usually taken as evidence for their marginal and tenuous status already in the preceding centuries. They are seen as optional, poetic, and unpredictable. It is the argument of this paper on the basis of the evidence of the Old English Genesis that these claims warrant a careful revision as – at least in this one poem – there is nothing random or irregular about their use.
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Authors and Affiliations

Marcin Krygier
1

  1. Adam Mickiewicz University Poznań
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Abstract

One of the concepts of the ventilation rate control in buildings with dense and unpredictable occupancies is based on the CO2 measurements. There are many limitations regarding the validity of CO2 measurement inputs as suitable to the ventilation rate control. Verifying research has been conducted in an air-conditioned auditorium, in the real conditions at altered ventilation air thermal parameters and variable occupancy. The CO2 and the number concentrations of the fine and coarse aerosol particles(> 0.3 μm) and bioaerosol particles (bacteria and staphylococci) as well as the indoor air thermal parameters were measured in the individual sectors of the occupied area. The sensory assessments and instrumental determinations of the acceptability of indoor air quality (ACC) were also performed. The ventilation control strategy based, apart from the CO2 measurements, on the continuous monitoring of the perceived air quality (PAQ) in the auditorium sectors has been suggested. The PAQ monitoring could be accomplished by aerosol concentration measurements and the ACC instrumental determinations. This strategy should ensure a desired PAQ in sectors which benefit the occupants' comfort, health and productivity as well as energy savings not only in the case of its implementation in the considered auditorium.
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Authors and Affiliations

Bernard Połednik
Marzenna Dudzińska
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Abstract

Food additives, especially E numbers, are widely perceived by consumers as artificial and harmful. However, the fact is that they are an essential ingredient in numerous products, many have “natural” origins and none of them pose a risk to health.

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Authors and Affiliations

Justyna Cybulska
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Abstract

The article presents the results of analyses of changes in the number of ponds in the Wys-koć catchment basin carried out in the years 1980–2003 and the characteristics of ponds excavated in that period. Only water reservoirs of an area less than 2 ha were considered. Analyses were based on topographic maps in the scale of 1:10 000 and aerial photographs taken in 1996. The results indicated that the number of filled ponds increased, especially those located in fields and grasslands. However, forest and wetland ponds were the most resistant to the processes of quantitative degradation because not even a single pond was filled during the analysed period. Over 70% newly excavated water bod-ies were made as an effect of exploitation of mineral and peat resources. However, nowadays ponds are more often created as a result of intentional human activities and are used for fish farming, recrea-tion and as water retention reservoirs used in irrigation of small agricultural and gardening areas.

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Authors and Affiliations

Radosław Juszczak
Andrzej Kędziora
Jacek Leśny
Janusz Olejnik
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Abstract

The article introduces a new proposal of a defuzzification method, which can be implemented in fuzzy controllers. The first chapter refers to the origin of fuzzy sets. Next, a modern development based on this theory is presented in the form of ordered fuzzy numbers (OFN). The most important characteristics of ordered fuzzy numbers are also presented. In the following chapter, details about the defuzzification process are given as part of the fuzzy controller model. Then a new method of defuzzification is presented. The method is named center of circles intersection (CCI). The authors compare this method with a similar geometric solution: triangular expanding (TE) and geometric mean (GM). Also, the results are compared with other methods such as center of gravity (COG), first of maxima (FOM) and last of maxima (LOM). The analysis shows that the proposed solution works correctly and provides results for traditional fuzzy numbers as well as directed fuzzy numbers. The last chapter contains a summary, in which more detailed conclusions are provided and further directions of research are indicated.

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Authors and Affiliations

H. Zarzycki
W.T. Dobrosielski
Ł. Apiecionek
T. Vince
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Abstract

The current research focuses on the implementation of the fuzzy logic approach for the prediction of base pressure as a function of the input parameters. The relationship of base pressure (β ) with input parameters, namely, Mach number (M), nozzle pressure ratio (η), area ratio (α), length to diameter ratio (ξ ), and jet control (ϑ ) is analyzed. The precise fuzzy modeling approach based on Takagi and Sugeno’s fuzzy system has been used along with linear and non-linear type membership functions (MFs), to evaluate the effectiveness of the developed model. Additionally, the generated models were tested with 20 test cases that were different from the training data. The proposed fuzzy logic method removes the requirement for several trials to determine the most critical input parameters. This will expedite and minimize the expense of experiments. The findings indicate that the developed model can generate accurate predictions
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Authors and Affiliations

Jaimon D. Quadros
1
ORCID: ORCID
Suhas P.
2
Sher A. Khan
3
ORCID: ORCID
Abdul Aabid
4
ORCID: ORCID
Muneer Baig
4
Yakub I. Mogul
5

  1. Fluids Group, School of Mechanical Engineering, Istanbul Technical University, Gümüs¸suyu, 34437 Istanbul
  2. Department of Mechanical Engineering, Sahyadri College of Engineering and Management, Mangaluru 575007, Karnataka, India
  3. Department of Mechanical Engineering, Kulliyyah of Engineering, International Islamic University Malaysia, 53100, Selangor, Malaysia
  4. Department of Engineering Management, College of Engineering, Prince Sultan University, 66833, Riyadh 11586, Saudi Arabia
  5. National Centre for Motorsport Engineering, University of Bolton, Bolton, BL3 5AB, UK
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Abstract

Chromosome numbers for 15 taxa of Hieracium s.lat. (including two taxa of Pilosella Vaill.) from Bosnia and Herzegovina, Bulgaria, Greece, North Macedonia, Poland, Romania and Slovakia are given and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. pannosum subsp. parnassi Nägeli & Peter from Greece (3x and 4x), and for an undescribed species of H. sect. Cernua from North Macedonia (4x). A new, diploid chromosome number was found in H. bracteolatum s.lat. from Greece.

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Authors and Affiliations

Krystyna Musiał
ORCID: ORCID
Zbigniew Szeląg
ORCID: ORCID
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Abstract

Chromosome numbers of 17 taxa of Hieracium s.str. from Bulgaria, Greece, Poland and Romania are specified and their metaphase plates are illustrated. Chromosome numbers are published for the first time for H. engleri R. Uechtr. (4x), H. kritschimanum Mattfeld & Zahn (3x), H. latifolium Link (3x), H. tephrosoma subsp. amaurocranum Zahn (5x), as well as five undescribed species belonging to the H. lachenalii agg. (3x), H. rohacsense agg. (4x), H. vagneri agg. (4x), H. vranjanum agg. (4x) and H. wiesbaurianum agg. (3x), and a new hybrid between H. caesium s.lat and H. umbellatum (4x).
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Authors and Affiliations

Krystyna Musiał
1
ORCID: ORCID
Zbigniew Szeląg
2
ORCID: ORCID

  1. Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University, Gronostajowa 9, 30-387 Cracow, Poland
  2. Pedagogical University of Cracow, Institute of Biology, Podchorążych 2, 30-084 Kraków, Poland
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Abstract

In November 1994 a first inventory of Tanaidacea from the Beagle Channel and at some stations of the Atlantic continental shelfwas obtained using epibenthic sledge samples. In total, 2175 specimens from 27 species of eight families of Tanaidomorpha and two families of Apseudomorpha were collected. Two species, Allotanais hirstutus (Beddard, 1886) and Apseudes heroae Sieg, 1986, strongly dominated this area. Generally low diversity and abundances were recorded for the western area of the Beagle Channel, while substantially higher values were reported at the eastern entrance on the Atlantic side of the Beagle Channel. Abundances slightly varied with depths, but not significantly.

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Authors and Affiliations

Anja Schmidt
Angelika Brandt
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Abstract

In thermos fluid dynamics, free convection flows external to different geometries, such as cylinders, ellipses, spheres, curved walls, wavy plates, cones, etc., play major role in various industrial and process engineering systems. The thermal buoyancy force associated with natural convection flows can play a critical role in determining skin friction and heat transfer rates at the boundary. In thermal engineering, natural convection flows from cylindrical bodies has gained exceptional interest. In this article, we mathematically evaluate an entropy analysis of magnetohydrodynamic third-grade convection flows from permeable cylinder considering velocity and thermal slip effects. The resulting non-linear coupled partial differential conservation equations with associated boundary conditions are solved with an efficient unconditionally stable implicit finite difference Keller-Box technique. The impacts of momentum and heat transport coefficients, entropy generation and Bejan number are computed for several values of non-dimensional parameters arising in the flow equations. Streamlines are plotted to analyze the heat transport process in a two-dimensional domain. Furthermore, the deviations of the flow variables are compared with those computed for a Newtonian fluid and this has important implications in industrial thermal material processing operations, aviation technology, different enterprises, energy systems and thermal enhancement of industrial flow processes.
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Authors and Affiliations

K. Madhavi
V. Ramachandra Prasad
S. Abdul Gaffar
K. Venkatadri
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Abstract

Overseas mining investment generally faces considerable risk due to a variety of complex risk factors. Therefore, indexes are often based on conditions of uncertainty and cannot be fully quantified. Guided by set pair analysis (SPA) theory, this study constructs a risk evaluation index system based on an analysis of the risk factors of overseas mining investment and determines the weights of factors using entropy weighting methods. In addition, this study constructs an identity-discrepancycontrary risk assessment model based on the 5-element connection number. Both the certainty and uncertainty of the various risks are treated uniformly in this model and it is possible to mathematically describe and quantitatively express complex system decisions to evaluate projects. Overseas mining investment risk and its changing trends are synthetically evaluated by calculating the adjacent connection number and analyzing the set pair potential. Using an actual overseas mining investment project as an example, the risk of overseas mining investment can be separated into five categories according to the risk field, and then the evaluation model is quantified and specific risk assessment results are obtained. Compared to the field investigation, the practicability and effectiveness of the evaluation method are illustrated. This new model combines static and dynamic factors and qualitative and quantitative information, which improves the reliability and accuracy of risk evaluation. Furthermore, this evaluation method can also be applied to other similar evaluations and has a certain scalability.

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Authors and Affiliations

Zhaoyang Ma
Guoqing Li
Nailian Hu
Di Liu

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