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Number of results: 6
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Abstract

The paper presents the result of an evaluation of the performance of different message broker system configurations, which lead to the construction of the specific architecture guidelines for such systems. The examples are provided for an exemplary middleware messaging server software - RabbitMQ, set in high availability - enabling and redundant configurations. Rabbit MQ is a message queuing system realizing the middleware for distributed systems that implements the Advanced Message Queuing Protocol. The scalability and high availability design issues are discussed and the possible cluster topologies and their impact is presented. Since HA and performance scalability requirements are in conflict, scenarios for using clustered RabbitMQ nodes and mirrored queues are interesting and have to be considered with specific workloads and requirements in mind. The results of performance measurements for some topologies are also reported in this article.

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Authors and Affiliations

Maciej Rostański
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Abstract

This work is an attempt to study the behaviour of fluid in the mixing vessel with a two-bladed or four-bladed impeller. The working fluid is complex, of a shear-thinning type and the Oswald model is used to describe the fluid viscosity. The study was accomplishedby numerically solving the governing equations of momentum and continuity. These equations were solved for the following range of conditions: 50–1000 for the Reynolds number, 0–0.15 for the baffle length ratio, and the number of impeller blades 2 and 4. The simulations were done for the steady state and laminar regime. The results show that the increase in baffle length (by increasing the ratio baffle length ratio) decreases the fluid velocity in the vessel. Increasing the speed of rotation of the impeller and/or increasing the number of blades improves the mixing process. Also, the length of the baffles does not affect the consumed power.
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Authors and Affiliations

Malika Seddik Bouchouicha
1
Houssem Laidoudi
1
Souad Hassouni
1
Oluwole Daniel Makinde
2

  1. University of Science and Technology of Oran Mohamed-Boudiaf, Faculty of Mechanical Engineering, BP 1505, El-Menaouer, Oran, 31000, Algeria
  2. Stellenbosch University, Faculty of Military Science, Private Bag X2, Saldanha 7395, South Africa
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

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Authors and Affiliations

Praveen Ailawalia
Sunil Kumar Sachdeva
Devinder Singh Pathania
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Abstract

Seed-borne diseases of wheat such as Fusarium head blight (FHB), a fungal disease caused by several species of Fusarium, results in reduced yield and seed quality. The aim of this study was to identify the Fusarium species, the effect of Fusarium-infected seeds on germination and vigor indices and to determine the location of Fusarium spp. in seeds, as well as to investigate the pathogenicity and variability of aggressiveness of the isolates obtained from pre-basic seeds wheat fields in Iran. According to morphological and molecular characters, the species F. graminearum, F. culmorum, F. avenaceum and F. poae were identified. Among the isolates, F. graminearum was the predominant species with the highest frequency and relative density of 92.9% and 70.9%, respectively. We observed that germination and vigor indices were decreased due to increased Fusarium-infected seeds. Results indicated significant differences among cultivars and seed-borne Fusarium levels. While a higher infection level of Fusarium spp. most commonly occurred in the seed coat, only F. graminearum was observed in embryos. Our study about pathogenicity showed that 77.3% of the Fusarium spp. isolates were not pathogenic and 22.7% isolates of Fusarium spp. were pathogenic or weakly pathogenic. Our results indicated that variability in aggressiveness among isolates of a species and positive correlation may be determined by pathogenicity tests. This is the first time the location of Fusarium spp. in seeds has been identified. It is also the first time that Fusarium-infected seeds in pre-basic seeds wheat fields of Iran have been evaluated.

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Authors and Affiliations

Farshid Hassani
Leila Zare
Nima Khaledi
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Abstract

The article deals with two issues: (1) the research method of father Georges Florovsky used in his study entitled The Ways of Russian Theology (1937), which is regarded a classic in its genre, and (2) the practice of scientific research conducted with the use of this method. The article is supplemented with Florovsky’s opinions, expressed in letters to his brother Anton, a professor at the Charles University in Prague, concerning the scientific achievements of the authors and scholars whom he met with or whom he came to work with after his departure to the USA (1948). The content of this correspondence has remained hitherto unpublished.

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Authors and Affiliations

Lilianna Kiejzik
ORCID: ORCID
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Abstract

The portrait of Heinrich Schwarzwald IV (1619–1672) was incorporated into the PAS Gdańsk Library’s collection back in 1832. Heinrich Schwarzwald IV was the founder of the book collection for the Petrischule in Gdańsk. The oil painting on canvas in a period frame with no signature was painted in the mid–1600s. Both the book collection and the portrait were actually donated to the school at St. Peter and Paul Church after the death of Heinrich Schwarzwald IV’s nephew, Heinrich Schwarzwald V, in 1708. For a long period of time the uncle’s merits were attributed to the nephew due to the same names. In 1860 Gotthilf Löschin identified the real founder of the above mentioned library. The article, in turn, settles down the matter of the identification of the portrayed person. The painting was presumably painted by Andreas Stech (1635–1697). The source data confirm the mutual contacts between the painter and Heinrich Schwarzwald IV. Before being donated to the library, the painting underwent an intensive and thorough restoration performed by Franz Joseph Manskirch in the 1820s.
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Authors and Affiliations

Krystyna Jackowska

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