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1

Distribution of ascaridoid nematodes (Nematoda: Chromadorea: Ascaridoidea) in fish from the Barents Sea

Najda K., Kijewska A., Kijewski T., Plauška K., Rokicki J.

Oceanological and Hydrobiological Studies

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2018

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Vol. 47, No. 2

128--139

EN

The Ascaridoidea are parasites with heteroxenous life cycles. The study shows that fish can be paratenic, intermediate, or final hosts for parasites, and parasitic fauna reflects the feeding behavior of the hosts. Each species of parasites has also different environmental preferences and host specificity. Parasitic nematodes of fish representing Pleuronectidae, Gadidae, Sebastidae, and Macrouridae were studied. Worms were collected separately from different infection sites: stomach, intestine, liver and body cavity. Nematodes were identified using both morphological and molecular methods (PCR-RFLP). Six nematode species were recorded: Anisakis simplex s.s., Contracaecum osculatum A, B, and C. osculatum C (s.s.), Hysterothylacium aduncum and Pseudoterranova bulbosa. Anisakis simplex s.s. was the most numerous nematode species of all catches combined. Differences in parasite species composition were related to the depth and location of sampling areas. In the fish from deep waters, the abundance of A. simplex s.s. decreased compared to fish from shallow waters and P. bulbosa was the dominant species. Ascaridoid species have specific preferences regarding the impact on various internal organs of fish, which is reflected in their abundance. The presence of Ascaridoidea in the Barents Sea is associated with the distribution of hosts and varying food preferences related to the age of fish. The abundance of parasites varied between different host species.

2

Parallel anisotropic mesh refinement with dynamic load balancing for transonic flow simulations

Gepner S., Majewski J., Rokicki J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

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Vol. 65, nr 2

195--207

EN

The present paper discusses an effective adaptive methods suited for use in parallel environment. An in-house, parallel flow solver based on the residual distribution method is used for the solution of flow problems. Simulation is parallelized based on the domain decomposition approach. Adaptive changes to the mesh are achieved by two distinctive techniques. Mesh refinement is performed by dividing element edges and a subsequent application of pre defined splitting templates. Mesh regularization and derefinement is achieved through topology conserving node movement (r-adaptivity). Parallel implementations of an adaptive use the dynamic load balancing technique.

3

Droplet bouncing on the surface with micro-structure

Bobinski T., Sobieraj G., Psarski M., Celichowski G., Rokicki J.

Archives of Mechanics

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2017

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Vol. 69, nr 2

177--193

EN

In this paper, we present static and dynamic interactions of water droplets with a micro-structured surface that exhibits hydrophobic properties. Droplets with two different diameters (D0 = 0.6 ± 0.1 mm and D0 = 2.6 ± 0.1 mm) were studied for impact velocities in the range of 0.1 ÷ 2.5 m/s. This allowed to investigate the influence of gravity on the collision behavior during an impact. The main result of the present research is the determination of the critical conditions for consecutive transitions leading to various scenarios of droplet rebound for each of the investigated surface geometry.

4

Contracaecum spp. from endemic Baikal fishes: the Baikal yellowfin Cottocomephorus grewingkii (Dybowski, 1874) and the longfin Baikal sculpin Cottocomephorus inermis (Yakovlev, 1890)

Rusinek O., Kulikowski M., Najda K., Rokicki J.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 1

68--73

EN

All the nematodes found in body cavities of the examined endemic Baikal fishes: 88 Baikal yellowfin Cottocomephorus grewingkii (Dybowski, 1874) and 35 longfin Baikal sculpin Cottocomephorus inermis (Yakovlev, 1890) were identified as Contracaecum osculatum baicalensis (Mozgovoi and Ryjikov, 1950) L3 larvae. The prevalence, mean intensity, intensity range and abundance of the nematodes in C. grewingkii were 37.5%, 2.55, 1-31, and 0.96, respectively, the corresponding values in C. inermis were 60.0%, 2.43, 1-10, and 1.46. The infestation level in C. grewingkii was significantly higher than in C. inermis (Mann-Whitney U-test, p<0.02). The number of parasites was found to increase with the fish length. Although in both and C. inermis, the anisakids were more frequent in males (prevalence of 52.17 and 67.76%, respectively) than in females (prevalence of 35.39 and 42.86%, respectively), differences between the sexes in the infestation level in the two species were not significant (Mann-Whitney U-test, P= 0.09 and P=0.23, respectively). The molecular method applied (PCF-RFLP) allows to identify all the nematodes in both examined fish species as C. osculatum baicalensis.

5

In vitro infection experiments with eggs of the nematode Contracaecum rudolphii Hartwich, 1964 (sensu lato) targeting aquatic insect larvae (Odonata : Coenagrionidae and Libellulidae; Trichoptera : Integripalpia) as possible intermediate hosts

Dziekońska-Rynko J., Rokicki J., Mierzejewska K.

Oceanological and Hydrobiological Studies

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2014

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Vol. 43, No. 2

165--169

EN

The availability of aquatic insects (Odonata: Coenagrionidae, Libellulidae and Trichoptera: Integripalpia) as potential intermediate hosts for the nematode Contracaecum rudolphii Hartwich, 1964 sensu lato was studied under laboratory conditions. The infective material consisted of nematode eggs, newly hatched larvae, as well as in vitro infected cyclopoid copepods. High prevalence and intensity of infection associated with a low mortality of aquatic insect larvae suggests that they may serve as intermediate hosts for C. rudolphii and constitute a major reservoir of C. rudolphii larvae in aquatic habitats.

6

Droplet impact in icing conditions – the influence of ambient air humidity

Bobinski T., Sobieraj G., Gumowski K., Rokicki J., Psarski M., Marczak J., Celichowski G.

Archives of Mechanics

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2014

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Vol. 66, nr 2

127--142

EN

The subject of the present paper is the applicability of hydrophobic surfaces for passive anti-icing protection. The experiments were focused on freezing droplets and on various droplet impingement and deformation scenarios. Droplet impact was investigated using high-speed camera for surfaces with different physico-chemical properties. To investigate the difference in droplet behavior on the surfaces with different wettability the steel and the aluminum plates were used and compared with specially designed surfaces characterized by a low surface energy. The influence of air humidity on droplet freezing was confirmed. The effective prevention of icing was observed only if humidity was removed from the system during the experiment.

7

Location and development of larvae of Contracaecum rudolphii Hartwich, 1964 (Nematoda: Anisakidae) in experimentally infected asps Leuciscus aspius (Linnaeus, 1758) (Pisces: Cyprinidae)

Dziekońska-Rynko J., Rokicki J., Mierzejewska K., Wziątek B., Bielecki A.

Oceanological and Hydrobiological Studies

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2013

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Vol. 42, No. 3

296--301

EN

Laboratory-reproduced and bred asps were experimentally infected with Contracaecum rudolphii larvae, either directly or with previously infected copepods. In the fish exposed to larval infection, the intensity and prevalence of infection were noticeably higher than in the group exposed to copepods. The course of larvae development was similar in both groups. In the larvae measuring ca. 1000 μm in length, the gastrointestinal tract with a developed ventriculus, ventricular appendix and intestinal caecum was clearly visible. The mouth was surrounded by three lips. Over the 10-week experimental period, slightly-coiled larvae surrounded with a thin theca but no encysted larvae were found in the fish exposed to larvae. On the other hand, spirally-stranded and encysted larvae were observed after the 7th week in the fish exposed to infected copepods. The results demonstrated that in the experimentally infected asps, the intensity and prevalence of infection as well as the location of the larvae in a fish depended on the type of invasive material applied.

8

Hybrid RANS/LES of plane jets impinging on a flat plate at small nozzle-plate distances

Kubacki S., Rokicki J., Dick E., Degroote J., Vierendeels J.

Archives of Mechanics

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2013

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Vol. 65, nr 2

143--166

EN

A k-ω based hybrid RANS/LES (Reynolds-averaged Navier-Stokes/large eddy simulation) model is tested for simulation of plane impinging jets at various nozzle-plate distances (H/B, where H is the distance and B is the slot's width) and various Reynolds numbers (based on the slot's width and the velocity in the symmetry plane). The studied combinations are H/B=2 for Re=10000, H/B=4 for Re=18000 and H/B=9.2 for Re=20000. The focus is on small distance of the nozzle exit to the plate. In LES mode, the hybrid RANS/LES model uses two definitions of the local grid size, one based on the maximum distance between the cell faces in the destruction term of the turbulent kinetic energy equation and one based on the cube root of the cell volume in the eddy-viscosity formula. This allows accounting for flow inhomogeneity on anisotropic grids. In RANS mode, the hybrid model turns into the newest version of the k-ω model by Wilcox.

9

Uszczelnienie czołowe: metody modelowania i analizy wpływu geometrycznej tekstury powierzchniowej

Dzikowski M., Rokicki J.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Nauki Techniczne

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2012

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Z. 17

43-49

PL

Możliwość dokładnej analizy wpływu geometrycznej tekstury powierzchniowej oraz chropowatości na właściwości mechaniczne uszczelnienia czołowego jest kluczowym elementem przy projektowaniu tych urządzeń. Stosowane powszechnie modele oparte o równanie Reynoldsa obarczone są pewnymi ograniczeniami, dlatego też celowe jest poszukiwanie metod umożliwiających pełniejszą analizę. Opisane tutaj metody wielofazowego gazu sieciowego Boltzmanna są narzędziem umożliwiającym dokładną analizę przepływu wielofazowego w obszarze o złożonej geometrii, jakim jest szczelina uszczelnienia czołowego.

EN

Detailed analysis of surface texture and roughness influence on face sealing trybological performance is crucial for design process of those devices. Methods based of Reynolds equation are in common use, however they have certain limitations. More accurate tools may be needed for more accurate parameters prediction. Multiphase lattice Boltzmann gas methods, described here, have possibility to perform detailed simulations of cavitating flow in complicated domains, witch is the case of the flow in the face seal.

10

Nematodes found in the European anchovy (Engraulis encrasicolus), a rare visitor to the Baltic Sea [commun.]

Kulikowski M., Rolbiecki L., Skóra K., Rokicki J.

Oceanological and Hydrobiological Studies

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2012

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Vol. 41, No. 3

99-102

EN

The European anchovy, Engraulis encrasicolus (Linnaeus, 1758), enters the Baltic Sea only occasionally. Little is known about the parasites that inhabit this fish in the northern part of its natural range (north-eastern Atlantic). This study is based on 32 anchovies sampled in autumn 2006 from a substantial bycatch accompanying sprat in the Gulf of Gdańsk (southern Baltic Sea). The fish were examined using standard parasitological procedures, and yielded 10 L3 larvae of the nematode Hysterothylacium aduncum (Rudolphi, 1802). The prevalence and the intensity (mean and range) were 21.9%, 1.4, and 1–4, respectively.

11

Extraction of centre line from curvilinear objects

Rokicki J., Matiukas V., Ušinskas A., Adaškevičius R.

Opto-Electronics Review

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2011

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Vol. 19, No. 1

22-29

EN

This tutorial paper surveys three methods designed to detect the centre line in curvilinear structures. These are the iterative thinning, Steger's and derivatives' methods. We aim to illustrate the effectivness of the chosen methods for processing laser-trace images and magnetic resonance slices of human head. The essence of each three methods is presented and important parameters are discussed. Experiments have been carried out and results are discussed in the light of the quality of the centre line produced and work time of all three methods.

12

Hybrid RANS/LES computation of plane impinging jet flow

Kubacki S., Rokicki J., Dick E.

Archives of Mechanics

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2011

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Vol. 63, nr 2

117-117

EN

Flow characteristics are presented of simulation results of plane impinging jets at high nozzle-plate distances, with two k-? based hybrid RANS/LES (Reynolds Averaged Navier–Stokes/Large–Eddy Simulation) models and a k-? RANS model. The first hybrid RANS/LES model is obtained by substitution of the turbulent length scale by the local grid size in the destruction term of the turbulent kinetic energy equation and in the definition of the eddy-viscosity. The second hybrid model is obtained by a latency factor in the definition of the eddy-viscosity. The RANS model overpredicts the length of the jet core region, caused by too weak turbulent mixing in the shear layers of the jet. This results in erroneous near-wall shear stress along the impingement plate. The hybrid RANS/LES models overcome the deficiency of the RANS model. Further, the hybrid models represent the flow with much more detail. For instance, the Görtler vortices are well reproduced in the stagnation flow region by the hybrid RANS/LES models.

13

Infestation of the black cormorants (Phalacrocorax carbo sinensis L. 1758) from the colony on the Selment Wielki, with the nematode Contracaecum rudolphii Hartwich, 1964 (Nematoda, Anisakidae)

Dziekońska-Rynko J., Rokicki J.

Oceanological and Hydrobiological Studies

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2008

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Vol. 37, No.4

61-71

EN

Seasonal changes in the intensity and prevalence of infestation of the black cormorants from the colony on Lake Selment Wielki were investigated. In 2006, the cormorants were procured in April, August, and October, while in 2007, they were collected in August and September. The prevalence of the infestation was very high and reached 100%. The highest intensity (mean values of 102.46 and 82.17 nematodes/bird in 2006 and 2007, respectively) was revealed in the cormorants shot in August. Intensity of infestation of those birds procured in autumn 2006 was more than twice that found in spring and one-fourth of that found in summer of that year. Similarly, in autumn of 2007, the birds’ stomachs contained less than half of the number of nematodes recorded in summer of that year.

14

Helminths of the lumpsucker (Cyclopterus lumpus) from the Gulf of Gdańsk and Vistula Lagoon (Poland)

Rolbiecki L., Rokicki J.

Oceanological and Hydrobiological Studies

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2008

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Vol. 37, No.4

53-59

EN

The lumpsucker (Cyclopterus lumpus Linnaeus, 1758) is a marine fish inhabiting shallow coastal areas of North Atlantic. In 1996-2006, 224 lumpsucker individuals caught in the Gulf of Gdańsk and Vistula Lagoon (Poland) were examined for metazoan parasites. The fish were found to support the cestode Eubothrium crassum (Bloch, 1779), the nematodes Contracaecum osculatum (Rudolphi, 1802) L3, Dichelyne minutus (Rudolphi, 1819), and Hysterothylacium aduncum (Rudolphi, 1802) L3, L4, ad. as well as the acanthocephalans Corynosoma strumosum (Rudolphi, 1802) cyst., Echinorhynchus gadi Zoega in Müller, 1776, and Pomphorhynchus laevis (Müller, 1776). The total (both areas) prevalence of parasites was 63.4% at a mean intensity of 2.1 inds. In the Gulf of Gdańsk, 66.3% of all the lumpsucker examined were infected (intensity 2 inds), the level of infection in the Vistula Lagoon being 46.5% of the fish (intensity 2.3 inds). The Gulf of Gdańsk lumpsucker supported all the parasitic species listed, while 4 species only ( E. crassum, H. aduncum, E. gadi, and P. laevis) were recorded in the Vistula Lagoon. The dominant parasites were H. aduncum (43.3%, 2.1 inds) and E. gadi (21.0%, 1.2 inds). All the parasitic species, except C. strumosum, are being reported from the southern Baltic lumpsucker for the first time.

15

Fast point location algorithm on triangular meshes

Wichulski M., Rokicki J.

Journal of Theoretical and Applied Mechanics

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2008

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Vol. 46 nr 2

315-324

EN

This paper is a study of application of persistent data structures to the planar and, in part, also spatial point location. In practice, a simplified method of building persistent red- black binary search tree is considered. It corresponds to the structure of a two-dimensional cell complex. Subsequent use of the structure for searching a certain point in space is shown. The computational mesh consists of triangular (in two dimensions) or tetrahedral (in three dimensions) cells. This fact allows significant simplifications to both implementation of the total order necessary to build the search tree as well as construction of the red-black binary search tree itself. The performance of the algorithm is verified for various meshes (consisting of up to 1846197 cells). Finally, certain further directions of the research are shown.

PL

Artykuł przedstawia wyniki badań nad zastosowaniem dynamicznych struktur danych (ang. persistent data structures) do planarnej i przestrzennej lokalizacji punktu w siatce obliczeniowej, z wykorzystaniem czerwono-czarnych drzew poszukiwań binarnych, które odpowiadają strukturze dwuwymiarowego kompleksu komórek. Rozważana siatka obliczeniowa składa się z komórek trójkątnych (w dwóch wymiarach) albo czworościennych (w trzech wymiarach). Ten fakt zezwala na znaczne uproszczenia realizacja totalnego porządku niezbędnego do budowy drzewa poszukiwań, jak również konstrukcji samego czerwono-czarnego drzewa poszukiwań binarnych. Wydajność algorytmu jest sprawdzone dla różnych siatek obliczeniowych (zawierających od 1239 do 1846197 komórek). Wyniki eksperymentu numerycznego potwierdzają logarytmiczny czas lokalizacji i liniowo rosnące zużycie pamięci przy wzroście rozmiaru siatki.

16

Third-order method for simulation of compressible flows

Wieteska R., Rokicki J.

Archives of Mechanics

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2008

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Vol. 60, nr 6

491-507

EN

The paper discusses finite volume WENO reconstruction applied to simulation of compressible 3D Euler flows. The main objective of this work is presentation of the new reconstruction procedure (third-order of accuracy in space), together with the procedure for integration of numerical fluxes applied to simulations of compressible 3D Euler flows, using unstructured meshes.

17

Zastosowanie elektromagnesów prądu stałego z przesuwną kotwicą w układach automatyki przemysłowej - główne kryteria doboru

Rokicki J.

Napędy i Sterowanie

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2007

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R. 9, nr 3

130-132

PL

W układach automatyki przemysłowej - np. obrabiarek, maszyn pakujących, maszyn dla przemysłu tekstylnego itd. - nierzadko zachodzi potrzeba wykonania określonej pracy mechanicznej, np. przesunięcia lub podniesienia detalu. Ostatnio przedmiotem zainteresowania konstruktorów stają się elektromagnesy, które w pewnych okolicznościach mogą śmiało konkurować ze stosowanymi dotychczas siłownikami - zespołami z pewnością bardziej od tych pierwszych uciążliwymi w eksploatacji. Celem niniejszego artykułu jest przedstawienie głównych aspektów i kryteriów doboru elektromagnesów do konkretnych zadań w automatyce przemysłowej.

18

Investigation of WENO schemes for 3D unstructured grids

Wieteska R., Majewski J., Rokicki J.

Computer Assisted Mechanics and Engineering Sciences

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2007

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Vol. 14, No. 3

457-470

EN

This paper paper discusses accuracy of WENO reconstruction used for unstructured grids and applied to two common discretization approaches within Finite Volume Method (FVM). They are Cell Centered and Vertex Centered methods. The numerical results are shown for 3D supersonic flow in a channel and for ONERA M6 wing. The comparison of computational performance of both methods is included.

19

Third-order WENO method on 3D unstructured tetrahedral mesches

Rokicki J., Wieteska R.

Systems : journal of transdisciplinary systems science

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2006

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Vol. 11, nr 1

74-85

EN

The paper discusses finite volume WENO reconstruction applied to simulation of compressible 3D Euler flows using unstructured tetrahedral meshes. The main point of interest is the case when the mesh becomes highly irregular or stretched. Special transformation is used in such cases to recover the third-order accuracy of reconstruction. This transformation has to be locally applied to each stencil on which the reconstruction is sought. This procedure is verified first on a sequence of 3D meshes in a unit cube. The performance of the full algorithm (including the extended nonlinear weighing) is verified for the 3D subsonic and transonic flows in a channel with smooth sinusoidal bump.

20

Wpływ niejednorości powierzchniowych na przepływ w uczszelnianiu czołowym

Antoszewski B., Rokicki J.

Inżynieria Chemiczna i Procesowa

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2006

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T. 27, z. 3/1

889-899

PL

Przedstawiono wyniki analizy modelu przepływu przez szczelinę uszczelnienia czołowego z modyfikowanymi powierzchniami roboczymi. Model przepływu oparto na zmodyfikowanym równaniu Reynoldsa obejmującym również obszary kawitacji i oderwania filmu smarnego w okolicy wgłębień w powierzchni ślizgowej. Otrzymano równanie typu mieszanego eliptyczno-hiperbolicznego, a jego rozwiązanie uzyskano za pomocą technik numerycznych podobnych jak w przepływach transonicznych. Rezultatem modelowania jest przewidywanie radialnego wydatku masowego, a także precyzyjne oszacowanie sił działających na parę ślizgową.

EN

The fluid flow has been analysed in the clearance of a face seal with modified working surfaces. The model of flow used for this study bases on the Reynolds equation, appropriately modified to include the areas of cavitation and separation near grooves on the sliding surface. The equation is of mixed elliptic -hyperbolic type and can be solved by employing numerical techniques similar to those used for transonic flows (upwind finite difference schemes). The modelling helps to predict the radial mass flow rate as well as to assess accurately the forces acting on a sliding pair.