On the Development of Low-Wave Resistance Hull Forms by Means of Off-Centerplane Singularity Distributions

http://deepblue.lib.umich.edu/bitstream/2027.42/96611/1/39015087359017.pd

Impact of the density of the mould powder on thickness of the layer of liquid slag in the continuous caster mould

The paper presents results of measurements of the thickness of liquid slag layer in concast mould for pulverized, granulated or formed mould powder. The thickest layer of liquid slag was obtained for formed powders

Shell-model calculations of two-neutrino double-beta decay rates of 48^{48}Ca with GXPF1A interaction

The two-neutrino double beta decay matrix elements and half-lives of $^{48}$Ca, are calculated within a shell-model approach for transitions to the ground state and to the $2^+$ first excited state of $^{48}$Ti. We use the full $pf$ model space and the GXPF1A interaction, which was recently proposed to describe the spectroscopic properties of the nuclei in the nuclear mass region A=47-66. Our results are $T_{1/2}(0^{+}\to 0^{+})$ = $3.3\times 10^{19}$ $yr$ and $T_{1/2}(0^{+}\to 2^{+})$ = $8.5\times 10^{23}$ $yr$. The result for the decay to the $^{48}$Ti 0$^+$ ground state is in good agreement with experiment. The half-life for the decay to the 2$^+$ state is two orders of magnitude larger than obtained previously.Comment: 6 pages, 4 figure

Dynamical systems analysis of spike-adding mechanisms in transient bursts

Transient bursting behaviour of excitable cells, such as neurons, is a common feature observed experimentally, but theoretically, it is not well understood. We analyse a five-dimensional simplified model of after-depolarisation that exhibits transient bursting behaviour when perturbed with a short current injection. Using one-parameter continuation of the perturbed orbit segment formulated as a well-posed boundary value problem, we show that the spike-adding mechanism is a canard-like transition that has a different character from known mechanisms for periodic burst solutions. The biophysical basis of the model gives a natural time-scale separation, which allows us to explain the spike-adding mechanism using geometric singular perturbation theory, but it does not involve actual bifurcations as for periodic bursts. We show that unstable sheets of the critical manifold, formed by saddle equilibria of the system that only exist in a singular limit, are responsible for the spike-adding transition; the transition is organised by the slow flow on the critical manifold near folds of this manifold. Our analysis shows that the orbit segment during the spike-adding transition includes a fast transition between two unstable sheets of the slow manifold that are of saddle type. We also discuss a different parameter regime where the presence of additional saddle equilibria of the full system alters the spike-adding mechanism

Canonical form of Hamiltonian matrices

On the basis of shell model simulations, it is conjectured that the Lanczos construction at fixed quantum numbers defines---within fluctuations and behaviour very near the origin---smooth canonical matrices whose forms depend on the rank of the Hamiltonian, dimensionality of the vector space, and second and third moments. A framework emerges that amounts to a general Anderson model capable of dealing with ground state properties and strength functions. The smooth forms imply binomial level densities. A simplified approach to canonical thermodynamics is proposed.Comment: 4 pages 6 figure

1H NMR spectroscopy study of structural water in rehydrated biocomposite of Spongilla lacustris freshwater demosponge origin

Biocomposites of sponge origin attract scientific attention due to their renewability as well as special properties. Dried skeletons of fresh water demosponge Spongilla lacustris represent unique kind of naturally occurring silica-chitin-based biocomposites with long history of their applications in dermatocosmetics. However, there is still a lack of knowledge on their physico-chemical properties in model systems. The aim of this work was to model drug systems based on S. lacustris powdered biocomposite, water and a hydrophobic medium, which served as an analog of an oil base. Both thermogravimetric analysis and 1H NMR spectroscopy study of structural water in rehydrated biocomposite lead to obtaining of interesting experimental data useful for preparation of biocosmetic products. © 2020, The Author(s).Deutsche Forschungsgemeinschaft, DFG: HE 394-3PPN/BEK/2018/1/00071Deutsche Forschungsgemeinschaft, DFGSächsisches Staatsministerium für Wissenschaft und Kunst, SMWK: 02010311This work was financially supported by German Research Foundation (DFG) Grant HE 394-3, SMWK Project 02010311 (Germany). M.W. is thankful for financial support from Polish National Agency for Academic Exchange (PPN/BEK/2018/1/00071) and support from Ministry of Science and Higher Education (Poland) as financial subsidy to PUT

Energy efficiency parametric design tool in the framework of holistic ship design optimization

Recent International Maritime Organization (IMO) decisions with respect to measures to reduce the emissions from maritime greenhouse gases (GHGs) suggest that the collaboration of all major stakeholders of shipbuilding and ship operations is required to address this complex techno-economical and highly political problem efficiently. This calls eventually for the development of proper design, operational knowledge, and assessment tools for the energy-efficient design and operation of ships, as suggested by the Second IMO GHG Study (2009). This type of coordination of the efforts of many maritime stakeholders, with often conflicting professional interests but ultimately commonly aiming at optimal ship design and operation solutions, has been addressed within a methodology developed in the EU-funded Logistics-Based (LOGBASED) Design Project (2004–2007). Based on the knowledge base developed within this project, a new parametric design software tool (PDT) has been developed by the National Technical University of Athens, Ship Design Laboratory (NTUA-SDL), for implementing an energy efficiency design and management procedure. The PDT is an integral part of an earlier developed holistic ship design optimization approach by NTUA-SDL that addresses the multi-objective ship design optimization problem. It provides Pareto-optimum solutions and a complete mapping of the design space in a comprehensive way for the final assessment and decision by all the involved stakeholders. The application of the tool to the design of a large oil tanker and alternatively to container ships is elaborated in the presented paper

Innovation in metallurgical waste management

In the paper was presented innovative solutions of sludge and dust management generated by metallurgical enterprises. These solutions are as follows: usage of steelmaking dust in production of decorative glassware and deoiling of metallurgical sludge useful in producing of iron-bearing briquette for electric arc furnaces (EAF). The influence of the aforementioned technologies on the environment was also discussed

How magic is the magic 68Ni nucleus?

We calculate the B(E2) strength in 68Ni and other nickel isotopes using several theoretical approaches. We find that in 68Ni the gamma transition to the first 2+ state exhausts only a fraction of the total B(E2) strength, which is mainly collected in excited states around 5 MeV. This effect is sensitive to the energy splitting between the fp shell and the g_{9/2}orbital. We argue that the small experimental B(E2) value is not strong evidence for the double-magic character of 68Ni.Comment: 4 pages, 4 figure