•The application of bicultural stock in RAS has the potential to benefit culture efficiency.•Physiology of rainbow trout and burbot were affected by the arrangement of biculture.•Highest proportion ...of the burbot in the stock ensured less sediment production.•A decreasing trend of solid production suggested adaptation to cultural conditions.•Bi-cultural stocks can be applied to enhance production in RAS.
Traditional monoculture systems often face challenges related to solid waste production and nutrient use. This study addresses these concerns by investigating the impact of bicultural farming of burbot (Lota lota) and rainbow trout (Oncorhynchus mykiss) in a recirculating aquaculture system (RAS) and the subsequent alteration of production of solid waste, growth and physiological status. The rationale behind incorporating burbot lies in its potential as a supplementary species to improve overall system efficiency and sustainability. The experimental groups in triplicate represented the different ratios of rainbow trout (T) and burbot (B) in the stock: T70/B30, T85/B15 and T100/B0. Burbot, although not assessed in monoculture due to its limited commercial significance, was incorporated into the study as a supplementary species, expected to enhance the nutrient utilisation through its bottom-feeding behaviour and anticipated consumption of solid waste produced by trout. After 77 days of culture, the survival rates of trout remained consistent across experimental groups, averaging over 99%, while burbot exhibited comparable survival rates despite lower cumulative survival, averaging 88%. Feed conversion ratios showed no significant differences between the groups, indicating consistent feed utilisation. A significantly higher specific growth rate (SGR) in trout was observed in group T70/B30. The SGR values of burbot were marginally low and without significant differences between groups. Among biochemical markers of blood plasma, phosphorus concentrations were significantly higher in group T70/B30 for both trout and burbot, suggesting better access to the feed for both species. Elevated antioxidant activity and evidence of oxidative stress were found for both species in intestinal tissue. The presence of burbot in stock significantly affected the production of suspended solids per gram of applied feed. Therefore, group T100/B0 demonstrated the highest solid production at multiple time points, suggesting a relationship between burbot presence and the production of suspended solids. Starting at the 9-week, the trout monoculture group exhibited significantly higher phosphorus levels in sediments compared to group T70/B30, emphasising the role of burbot in shaping sediment nutrient dynamics in RAS, such as supplementary cleaning fish. After 11 weeks, group T100/B0 displayed significantly higher values of produced suspended solids and their composition: DM, organic DM, and phosphorus content per gram of feed applied. These results provide evidence of the influence of burbot on suspended solids production and characteristics. In conclusion, this study indicates the positive effects of burbot presence on solid production and sediment nutrient composition.
Glutinoglossum is one of the earth tongue genera with viscid or glutinous ascocarps. Based on morphology and ITS1-5.8S-ITS2, nrLSU and tef1 sequence data, seven new species are described: G. ...circinatum, G. lumbricale, G. orientale, G. peregrinans,
G. proliferatum, G. pseudoglutinosum, and G. triseptatum. The lectotypes for Geoglossum glutinosum var. lubricum and for Geoglossum glabrum var. majus as well as the epitype for Glutinoglossum glutinosum are designated. The comprehensive
morphological study of G. heptaseptatum resulted in the discovery of ascospores germinating by conidia inside the asci, which is first noted for Glutinoglossum species. The status of Cibalocoryne is discussed.
In this work, Al-17Fe alloys (wt%) were prepared by a combination of different techniques, including centrifugal atomization and mechanical milling, followed by compaction via hot extrusion or ...advanced spark plasma sintering. Both alloys exhibited a satisfactory hardness of approximately 120HV 5, which is almost identical to the reference Al-12Si-1Cu-1Mg-1Ni casting alloy. However, when annealed at 400°C for up to 100h, the investigated alloys showed excellent thermal stability, which manifested as an almost negligible change in the initial hardness. In comparison, the reference Al-12Si-1Cu-1Mg-1Ni alloy softened considerably, with a decrease in hardness by almost 50% to 63HV 5. Compressive stress-strain tests of compact samples at laboratory temperature or at an elevated temperature of 400°C in the initial state and after 100h of annealing at 400°C confirmed similar or superior ultimate compressive and compressive yield strengths for both the Al-17Fe alloys compared to the reference Al-12Si-1Cu-1Mg-1Ni alloy, which softened considerably when annealed at the elevated temperatures. More importantly, the centrifugally atomized and hot-extruded Al-17Fe alloy exhibited outstanding ductility, reaching 34%, even when compressively tested at laboratory temperature.
Display omitted
•The Al-17Fe alloy showed remarkable microstructural refinement during the processing.•Both the alloys showed hardness of 120 HV 5 comparable to the reference Al-12Si-1Cu-1Mg-1Ni casting alloy.•Excellent thermal stability of prepared Al-17Fe confirmed by almost negligible hardness change during long-term annealing.•Superior ultimate compressive and compressive yield strengths for both the Al-17Fe alloys even after annealing.•Combination of centrifugal atomization and hot extrusion resulted in increased ductility reaching outstanding 34 %.
This work is concerned with the simulation of inviscid compressible flow in time-dependent domains. We present an arbitrary Lagrangian–Eulerian (ALE) formulation of the Euler equations describing ...compressible flow, discretize them in space by the discontinous Galerkin method and introduce a semi-implicit linearized time stepping for the numerical solution of the complete problem. Special attention is paid to the treatment of boundary conditions and the limiting procedure avoiding the Gibbs phenomenon in the vicinity of discontinuities. The presented computational results show the applicability of the developed method.
In the paper, we describe a numerical technique allowing the solution of compressible inviscid flow with a wide range of Mach numbers. The method is based on the application of the discontinuous ...Galerkin finite element method for the space discretization of the Euler equations written in the conservative form, combined with a semi-implicit time discretization. Special attention is paid to the treatment of boundary conditions and to the stabilization of the method in the vicinity of discontinuities avoiding the Gibbs phenomenon. As a result we obtain a technique allowing the numerical solution of flows with practically all Mach numbers without any modification of the Euler equations. This means that the proposed method can be used for the solution of high speed flows as well as low Mach number flows. Presented numerical tests prove the accuracy of the method and its robustness with respect to the Mach number.
In this paper we devise an efficient and robust numerical method for a nonlocal nonlinear model of flocking dynamics. The governing equations are a hydrodynamic limit of the model of Cucker and Smale ...which consists of the compressible Euler equations with added nonlinear nonlocal interaction terms. The numerical scheme is based on the discontinuous Galerkin method. A semi-implicit scheme is used in the time discretization which requires only the solution of one linear system per time level while retaining the stability of an implicit scheme. A crucial point is the construction of a suitable linearization of the nonlocal terms which does not result in fill-in of the system matrices. Element-wise and inter-element artificial diffusion is added to the scheme along with a postprocessing procedure to deal with near-vacuum states that typically arise in the solution. We demonstrate the efficiency and robustness of the scheme on numerical experiments in 1D and 2D.
•A numerical method for a nonlinear nonlocal model of flocking dynamics is proposed.•A semi-implicit discontinuous Galerkin discretization is applied.•A linearization is constructed so the nonlocal terms do not give a full system matrix.•Stabilization is added near shocks along with a treatment of near-vacuum which arise.•Numerical experiments are given in 1D and 2D.
Recent results on positive polynomials are used to obtain a convex inner approximation of the stability domain in the space of coefficients of a polynomial. An application to the design of ...fixed-order controllers robustly stabilizing a linear system subject to polytopic uncertainty is then proposed, based on linear matrix inequality optimization. The key ingredient in the design procedure resides in the choice of the central polynomial. Several numerical examples illustrate the relevance of the approach.
A new species from Slovakia and the Czech Republic, Pseudoplectania lignicola, is described and illustrated. It is distinguished from other members of the genus by a centrally arranged globose ...membranous sheath surrounding the spores, thick ectal excipulum of oblong cells at
the apothecial base, and growth on less specifc biotopes. Comparisons with similar species and the diagnostic signifcance of membranous sheath surrounding the ascospores are also discussed.
The problem of the generalized output regulation is considered here. In contrast to the classical output regulation problem, where the references to be tracked and disturbances to be rejected are ...generated by an autonomous exogeneous system, for the generalized output regulation an exogenous system is driven by an unknown external reference signal. In such a way, the class of reference or disturbance signals is expanded. Presented result solves the full measurement feedback case and is based on the well-known notion of the regulator equation combined with the classical concept of the invariant distribution. Illustrative example, including MATLAB-SIMULINK simulations, is presented to demonstrate the suggested approach.
PDF
