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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Casting covers major area of production all over the world. Resin bonded casting is widely used in today’s manufacturing industries. Furan
No bake casting is most widely accepted in indian foundries due to its excellent surface finish and dimensional stability. It is a self-setting
binder and it has a lower work and strip times. Though the casting process is also known as process of uncertainty, in the present study, an
attempt has been made to investigate the effect of Grain Fineness Number, Loss of Ignition, Potential of Hydrogen, % of Resin with
respect to sand, Sand Temperature and Compressive strength of the mould on Sand Inclusion defect – one of the most dominating defect in
the Krislur Castomech Pvt. Ltd. Industry situated at Bhavnagar, Gujarat, India. The experiments were conducted based on response surface
methodology (RSM) and sequential approach using face centered central composite design. The results show that quadratic model with
removal of some insignificant term is comparatively best fits for Sand Inclusion Defect.