Icefish Adaptations to Climate Change on the South Georgia Island Shelf (Sub-Antarctic)

Ryszard Traczyk,Victor Benno Meyer-Rochow,Robert M. Hughes 한국해양과학기술원 2020 Ocean science journal Vol.55 No.2

Icefish populations continue to decline. Historical as well as current over-exploitations of stocks aggravated by climate change are frequently seen as responsible for the decline. However, natural oscillations in Antarctic fish and krill populations associated with natural climatic fluctuations, co-occurring with fisheries exploitation hinder determining the reasons for the population changes and the extent that long-term climate change may play in it. Based on data collected from South Shetland and South Orkney Islands (2956 fish stations) and South Georgia Island (2460 fish stations) covering a period from 1976 to 2017 we sought to relate decreases in krill and icefish populations to predator-prey interactions coupled with global warming influences. Our results show that the situation is complex and that many factors, e.g., competition between different icefish species, food choice and availability, and growth parameters, need to be considered. Pseudochaenichthys georgianus and Chaenocephalus aceratus biomasses, for example, oscillate in opposite directions and the two species differ with regard to the ranges they occupy in cold and warm water years. This reduces their competition for food, so that their combined biomasses oscillate little with thermal changes.

Effectiveness of Various Deproteinization Processes of Bovine Cancellous Bone Evaluated via Mechano-Biostructural Properties of Produced Osteoconductive Biomaterials

Ryszard Uklejewski,Mariusz Winiecki,Grzegorz Musielak,Renata Tok owicz 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.2

The purpose of this work was to characterize the results of five different processes of bovine tissue deproteinization, resulting in the fabrication of deproteinized xenogenic osteoconductive biomaterials for bone tissue regeneration as an alternative to autogenic bone grafts. The studies on deproteinization processes of bovine cancellous bone specimens, excised from fresh femoral bovine heads, included the following five processes: thermal deproteinization and four chemical deproteinization processes using the solutions 2.6 wt% sodium hypochlorite, 7 wt% hydrogen peroxide, 1 N potassium hydroxide and 1 N sodium hydroxide. The optimal parameters of the thermal deproteinization were designed on the basis of thermogravimetric analysis (TGA) of bovine bone specimens during a pilot study of the process. Periodical evaluation of all the processes of chemical deproteinization was performed via the assessment of protein concentration in bone specimens by the Lowry method. The mechanical properties of deproteinized bone specimens were evaluated by compression testing in the air-dry condition. The compressive strength of the completely deproteinized bone specimens after the thermal deproteinization process was remarkably lower compared with those after the chemical deproteinization processes: 6.5 times lower compared with those deproteinized with 7 wt% hydrogen peroxide solution and 3 times lower compared with those deproteinized with 2.6 wt% sodium hypochlorite solution. The SEM examination of deproteinized bone specimens showed microcracks on the trabecular surfaces generated by thermal deproteinization stresses. The presence of microcracks in the biomaterial resulted in a decrease in its ultimate compressive strength.

EPR spectroscopy and imaging of TEMPO-labeled magnetite nanoparticles

Ryszard Krzyminiewski,Tomasz Kubiak,Bernadeta Dobosz,Grzegorz Schroeder,Joanna Kurczewska 한국물리학회 2014 Current Applied Physics Vol.14 No.5

The article presents results of a study of TEMPO-labeled polymer coated superparamagnetic iron(II,III) oxide nanoparticles using both Electron Paramagnetic Resonance (EPR) spectroscopy and Electron Paramagnetic Resonance imaging technique (EPRI). The X-band (9.4 GHz) EPR spectroscopy was used to investigate the behavior of TEMPO-labeled polymer coated magnetite nanoparticles in different conditions (temperature and orientation in magnetic field). The broad line, which comes from the core of Fe3O4 nanoparticles, shows anisotropy. This signal broadens with decreasing temperature, its intensity increases with increasing temperature and the g factor decreases with increasing temperature. The shape of the signal from nitroxide radical strongly depends on temperature. When temperature is higher than 200 K, a narrow triplet appears, but when it is lower than 200 K the signal consists of broad asymmetric lines. Analysis of the signal allowed characterization of the motion of the spin label attached to nanoparticles. Values of anisotropy parameter 3 and rotational correlation time sc were calculated for TEMPO in the fast rotation regime. The ability of TEMPO-labeled PEG coated magnetite nanoparticles to diffuse within the hydrogel mediumwas also investigated. The EPR imaging of nanoparticles diffusion in hydrogel was made at room temperature using an EPR L-band (1 GHz) spectrometer. EPRI has been proved effective for evaluation of changes in the spatial distribution of nanoparticles in the sample.

Control of integrated electro-hydraulic servo-drives in a translational parallel manipulator

Ryszard Dindorf,Piotr Wos 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

This paper deals with the kinematics, dynamics and control of an innovative application of a three degrees of freedom (3-DoF) translational parallel manipulator (TPM) with three independently controlled integrated electro-hydraulic servo-drives (IEHSDs) for the handling of heavy forgings during precision machining. With high payload of the TPM moving platform, IEHSD force and position control was analyzed using adaptive controllers. The main contribution of this study is the IEHSD control architecture, which enables highly accurate synchronization of their position confirmed experimentally during TPM trajectory tracking control. For this purpose, a synchronization controller of three IEHSDs utilizing cross-coupled control (CCC) was proposed. The synchronizing controller ensures precise control of the TPM under conditions of variable heavy technological load.

Age Structure and Biomass of the Icefish Pseudochaenichthys georgianus Norman (Channichthyidae) Between 1976 and 2009: a Possible Link to Climate Change

Ryszard Traczyk,Victor Benno Meyer-Rochow 한국해양과학기술원 2019 Ocean and Polar Research Vol.41 No.4

A re-assessment of the age structure of the population of the Antarctic icefish Pseudochaenichthys georgianus based on body length data covering the years 1976−2009 and including larvae and postlarvae collected in 1989 and 1990 allowed us to define age groups 0, I, and II as containing fish with respective body lengths of 6−9 cm, 15−27 cm and 27−39 cm. Age at maturity (first spawning) was found to occur in age group III at body lengths that have been falling from 50.1 cm in 1979 to 45.4 cm in 1992. Considering postlarvae together with adult fish, the v. Bertalanffy growth curve parameters were determined as L∞ = 60.62 cm, k = 0.4, t0 = 0.25. Although the reasons for a maturity at shorter body lengths is not fully understood a host of environmental factors like increasing water temperatures and possibly changes in currents, interspecific competition, food availability, etc. are likely to be involved. Global warming (and not primarily overfishing) is likely to have been responsible for the disappearance of larger fish in the surface waters of South Georgia since 1977, for virtually all commercial fishing stopped in the early 1990s. On the other hand, the appearance of numerous younger spawning individuals suggests that larvae do survive in the colder deeper water below 200 m. The biomass of Ps. georgianus oscillates with a 4-year periodicity in contrast to that of the coexisting icefish Chaenocephalus aceratus: the former with a lower biomass in warm years and a higher one in cold years. The biomass of the third species of icefish in the region, i.e. Champsocephalus gunnari, also oscillates, but with a longer periodicity than that involved in the biology of the other two and its biomass increases in contrast to the other two species. The result is that the biomass all three species considered together is rather stable.

The SPARC/G methodology for inductively describing and predicting discrete processes

RYSZARD MICHALSKI,HEEDONG KO(고희동),KAIHU CHEN 한국정보과학회 1990 한국정보과학회 학술발표논문집 Vol.1990 No.5

Topology optimization of the structure using multimaterial inclusions

Ryszard KutyIowski 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.33 No.2

In the literature the problem of the topology optimization of the structure is usually solved for one, clearly described from the mechanical point of view material. Generally the topology optimization answers the question of the distribution of this mentioned above material within the design domain. Finally, material-voids distribution it is obtained. In this paper, for the structure mainly strengthened or sometimes weakened by the inclusions, the variation approach of the topology optimization problem is formulated. This multi material approach may be useful for the design process of various mechanical or civil engineering structures which need to be more ”refined” and more “optimal” than they can be using previous topology optimization procedures of optimization one material structures.

On fully filial torsion rings

Ryszard Romuald Andruszkiewicz,Karol Pryszczepko 대한수학회 2019 대한수학회보 Vol.56 No.1

Rings in which all accessible subrings are ideals are called filial. A ring $R$ is called fully filial if all its subrings are filial (that is rings in which the relation of being an ideal is transitive). The present paper is devoted to the study of fully filial torsion rings. We prove a classification theorem for semiprime fully filial torsion rings.

Otolith Microstructural Organization in the South Georgia Icefish Pseudochaenichthys georgianus (Channichthyide) and Cautious Considerations on How Otoliths Can Provide Clues on a Species’ Distribution and Migration in Antarctic Waters

Ryszard Traczyk,Victor Benno Meyer-Rochow 한국해양과학기술원 2022 Ocean and Polar Research Vol.44 No.1

How in the Antarctic icefish, generally, and Pseudochaenichthys georgianus, in particular, otoliths increase in size and build new material as the fish ages and passes through different life phases is largely unexplored. Morphometric details of 3418 otoliths of Ps. georgianus from S. Georgia and 318 from S. Shetland, were processed and proportions of the amounts of collagen and aragonite removed by EDTA were determined for different age groups. Microstructural investigations showed that characteristics of the 3-dimensinal collagen net are the reason for the radial direction and orientation of the aragonite needles of approximately 1.0 µm in length in larval and 2.3 µm in length in adult specimens. Earlier generated increment layers from the primordial centre (PC) in the dorsal direction restrict those of the secondary centre (SC), causing new growth layer accretion in different directions. In the otoliths of larval Ps. georgianus, aragonite layers are 0.89 µm wide while in juveniles and adults they measure 1.45–2.86 µm. Otoliths change from a sphere shape in the larvae to a longish object of irregular outline in the older stages. It is tentaively suggested that the observed otolith shape differences at distinct growth stages are due to physical effects related to swimming speeds at particular water depths and locations. To confirm that otoliths, apart from being useful for age analyses, could also serve to establish correlations between developmental stage and the oceanic environment the fish spend time in, further analyses using additional species and state-of-the-art methods like µCT imaging to evaluate otolith volumes and shapes are required.

The use of topology optimization in the design of truss and frame bridge girders

Ryszard Kutyłowski,Bartosz Rasiak 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.1

It is shown that topology optimization is a valuable tool for the design of bridge girders. This paper is a follow-up to (Kutyłowski and Rasiak 2014) and it includes an analysis of truss members’ outer dimensions dictated by the standards. Moreover, a frame bridge girder mapped from a selected topology is compared with a typical frame girder on the basis of (Kutyłowski and Rasiak 2014). The analysis shows that topology optimization by means of the proposed algorithm yields a topology from which one can map a frame bridge girder requiring less material for its construction than the typical frame girder currently used in bridge construction.