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Number of results: 67
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Abstract

The paper reports meiotic studies on 50 populations comprising 12 species belonging to 5 genera of Caryophyllaceae from the Western Himalayas. The chromosome numbers in Arenaria kashmirica (n=20), Silene conoidea (n=20), S. edgeworthii (n=12 and n=24), S. moorcroftiana (n=24), S. nepalensis (n=12), Stellaria media (n=13), S. monosperma (n=13) and S. semivestita (n=13) are reported for the first time. The chromosome numbers in Lychnis coronaria (n=12) and Silene vulgaris (n=24) are given for the first time from India, along with Gypsophilla ceratioides (n=15) from the Western Himalayas. The course of meiosis varies from normal to abnormal in different populations of Silene conoidea, S. edgeworthii, S. vulgaris, Stellaria media, S. monosperma and S. semivestita. The course of meiosis was abnormal in all studied populations of Lychnis coronaria. Abnormal microsporogenesis (cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges) led to reduced pollen fertility and differences in pollen grain size.

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Authors and Affiliations

Syed Mudassir Jeelani
Savita Rani
Sanjeev Kumar
Santosh Kumari
Raghbir Chand Gupta
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Abstract

Chromosome numbers of 46 Hieracium L. and Pilosella Vaill. taxa from Austria, Bulgaria, Czech Republic, Macedonia, Montenegro, Poland, Romania, Serbia and Slovakia are presented. Chromosomes numbers are given for the first time for Hieracium amphigenum Briq. 2n = 3× = 27, H. bohatschianum Zahn 2n = 4× = 36, H. borbasii R. Uechtr. 2n = 4× = 36, H. cernuum Friv. 2n = 2× = 18, H. hazslinszkyi Pax 2n = 3× = 27, H. mirekii Szeląg 2n = 4× = 36, H. polyphyllobasis (Nyár. & Zahn) Szeląg 2n = 3× = 27, H. porphyriticum A. Kern. 2n = 4× = 36, H. racemosum Waldst. & Kit. ex Willd. subsp. racemosum 2n = 3× = 27, H. scardicum Borm. & Zahn 2n = 4× = 36, H. sparsum subsp. ipekanum Rech. fil. & Zahn 2n = 4× = 36, H. sparsum subsp. peristeriense Behr & Zahn, H. sparsum subsp. squarrosobracchiatum Behr & al. 2n = 3× = 27, H. tomosense Simk. 2n = 4× = 36, H. tubulare Nyár. 2n = 4× = 36, H. werneri Szeląg 2n = 3× = 27 and Pilosella fusca subsp. subpedunculata (Zahn) Szeląg, as well as five species of Hieracium sect. Cernua R. Uechtr. not described to date and a hybrid between H. bifidum s. lat. and H. pojoritense Woł

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Authors and Affiliations

Tomasz Ilnicki
Zbigniew Szeląg
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Abstract

Chromosome numbers for 15 taxa of Hieracium L. s.str. from Bulgaria, Greece, Macedonia, Poland, Romania

and Slovakia are given and their metaphase plates are illustrated. Chromosome numbers are published for the

first time for H. vagneri Pax s.str. (2n = 4x = 36), H. wiesbaurianum subsp. herculanum Zahn (2n = 4x = 36),

H. wiesbaurianum subsp. kelainephes Nyár. & Zahn (2n = 3x = 27), as well as for two undescribed species

of hybrid origin between H. umbellatum L. and H. wiesbaurianum s.lat. (2n = 3x = 27), and between H. sparsum

Friv. and H. schmidtii s.lat. (2n = 3x = 27), and for three undescribed species of the H. djimilense agg.

(2n = 3x = 27), H. heldreichii agg. (2n = 3x = 27), and H. sparsum agg. (2n = 3x = 27). Furthermore, the chromosome

numbers of two undescribed species of hybrid origin between H. umbellatum L. and H. wiesbaurianum

s.lat. (2n = 3x = 27), and between H. sparsum Friv. and H. schmidtii s.lat. (2n = 3x = 27) are given. A new,

tetraploid chromosome number is given for H. barbatum Tausch from the northernmost locality of the species

in Europe.

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Authors and Affiliations

Krystyna Musiał
Agnieszka Janas
Zbigniew Szeląg
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Abstract

The present work deals with population-based meiotic studies on eight species belonging to four genera of the family Commelinaceae from different regions of Kangra Valley which is well known for its rich floristic diversity. At the world level, different cytotypes for four species such as Commelina hasskarlii (2n = 22, 60), C. kurzii (2n = 60), Murdannia nudiflora (2n = 24) and M. spirata (2n = 24) have been recorded for the first time at various ploidy levels. Additionally, from India, the new chromosome count for Tradescantia pallida (2n = 24) has been reported at the tetraploid level. The course of meiosis has been found to be normal in all the populations of Commelina benghalensis, C. paludosa, Murdannia nudiflora and M. spirata while four species, Commelina hasskarlii, C. kurzii, Cyanotis cristata and Tradescantia pallida have shown a normal to abnormal meiotic course in different populations. These meiotic abnormalities have revealed a clear effect on the pollen size and pollen fertility.
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Authors and Affiliations

Harpreet Kaur
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Abstract

Scheuchzeria palustris is a species regarded as an arctic-boreal relic and critically en-dangered. The study was conducted on one of the recent stands in the Łódź region, in the Czarny Ług Reserve, located near Wolbórz. The primary aim of the study was to know the amount of this species and the associated species. Quantitative, morphological and floristic features were ana-lysed. In the study area occurred about 150 specimens per 1 m2. Among the associated species were found species representing classes: Scheuchzerio-Caricetea Nigrae and Oxycocco-Sphagnetea. Eriopho-prum angustifolium was dominant among the first class species (60% coverage), while Andromeda polifolia and Oxycoccus palustris from the second class. From here it can be assumed that the succession will be in the direction of Scheuchzerio-Caricetea Nigrae. However, high water levels may inhibit this process. Specific biotic and abiotic conditions allow for the survival of this spe-cies. This is visible, among other things, in the mosaic structure of the studied stand.
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Authors and Affiliations

Ryszard Plackowski
Joanna Sender
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Abstract

Our survey of data collected in the Chromosome Number Database for Polish angiosperms indicated that the 1,498 species with chromosome counts represent 40% of the total angiosperms (3,719) occurring in Poland, including 1,205 native species (53% of native species) and 194 anthropophytes (56% of anthropophytes). The chromosome numbers are known for all native species occurring in Poland within 298 genera and 46 families, and for all anthropophytes from 79 genera and 11 families. The remaining angiosperm groups are less explored: chromosome counts from Poland are known for 9% of cultivated species and 5% of ephemerophytes. According to generic basic chromosome numbers, 46.44% of Polish angiosperms have been classified as polyploid. By three different threshold methods, the contribution of polyploid plants to the Polish flora is 64.64%, 50.89% or 42.89%. Polyploidy is more common among indigenous than non-indigenous plants, and the ploidy distribution among plants from the Polish Tatras does not differ significantly from that observed in the rest of native Polish plants.

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Authors and Affiliations

Grzegorz Góralski
Paulina Gacek
Andrzej Joachimiak
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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

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

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

We address one of the weaknesses of the RSA ciphering systems i.e. the existence of the private keys that are relatively easy to compromise by the attacker. The problem can be mitigated by the Internet services providers, but it requires some computational effort. We propose the proof of concept of the GPGPU-accelerated system that can help detect and eliminate users’ weak keys. We have proposed the algorithms and developed the GPU-optimised program code that is now publicly available and substantially outperforms the tested CPU processor. The source code of the OpenSSL library was adapted for GPGPU, and the resulting code can perform both on the GPU and CPU processors. Additionally, we present the solution how to map a triangular grid into the GPU rectangular grid – the basic dilemma in many problems that concern pair-wise analysis for the set of elements. Also, the comparison of two data caching methods on GPGPU leads to the interesting general conclusions. We present the results of the experiments of the performance analysis of the selected algorithms for the various RSA key length, configurations of GPU grid, and size of the tested key set.

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Authors and Affiliations

Przemysław Karbownik
Paweł Russek
Kazimierz Wiatr
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Abstract

The problem considered in the paper is motivated by production planning in a foundry equipped with a furnace and a casting line,

which provides a variety of castings in various grades of cast iron/steel for a large number of customers. The goal is to create the order of

the melted metal loads to prevent delays in delivery of goods to customers. This problem is generally considered as a lot-sizing and

scheduling problem. However, contrary to the classic approach, we assumed the fuzzy nature of the demand set for a given day. The paper

describes a genetic algorithm adapted to take into account the fuzzy parameters of simultaneous grouping and scheduling tasks and

presents the results achieved by the algorithm for example test problem.

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Authors and Affiliations

J. Duda
A. Stawowy
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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

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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Abstract

In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al2O3/H2O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k-" turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.

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Authors and Affiliations

Olatomide G. Fadodun
Adebimpe A. Amosun
Ayodeji O. Salau
David O. Olaloye
Johnson A. Ogundeji
Francis I. Ibitoye
Fatai A. Balogun

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