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[en] The concepts of the cities we know nowadays, and which we are accustomed to, change at a very rapid pace. The philosophy of their design is also changing. It will base on new standards, entering a completely different, futuristic dimension. This stage is related to changes in the perception of space, location and lack of belonging to definite, national or cultural structures. Cities of the future are cities primarily intelligent, zero-energetic, zero-waste, environmentally sustainable, self-sufficient in terms of both organic food production and symbiosis between the environment and industry. New cities will be able to have new organisational structures—either city states, or, apolitical, jigsaw-like structures that can change their position—like in the case of the city of Artisanopolis, designed as a floating city, close to the land, reminiscent of the legendary Atlantis. This paper is focused on the main issues connected with problems of the contemporary city planning. The purpose of the research was to identify existing technological solutions, whose aim is to use solar energy and urban greenery. The studies were based on literature related to future city development issues and futuristic projects of the architects and city planners. In the paper, the following issues have been verified: futuristic cities and districts, and original bionic buildings, both residential and industrial. The results of the analysis have been presented in a tabular form.
[en] The two-temperature structure of gas filtration combustion in an inert porous medium has been considered. The final interphase heat transfer, a strong temperature dependence of reaction rate have been assumed, the diffusion and pressure gradient in the gas phase have been neglected. A connection between the concentration and the temperature gradient of the second phase has been defined. (author)
[en] In this paper we provide a detailed analysis of heat generation in a solid-state laser medium. The fractional thermal loadings are different for different physical processes in a laser medium, including the fluorescence process, stimulated emission, energy transfer up-conversion and excited-state absorption. Applying this theoretical analysis in a diode-end-pumped Nd:GdVO4 laser at 1342 nm, and using a simple and efficient method to measure the thermal loading of the solid-state laser medium presented, the experimental results are in good agreement with the theoretically calculated results. (paper)
[en] The goal of this paper is to identify, for the first time, the role of solar production in driving silver prices. The empirical analysis makes use of the ARDL model and the combined cointegration. The results, spanning the period 1990–2016, document that stronger solar installed capacities, as well as higher gross electricity production from solar sources, lead to higher silver prices. The findings could be of great importance to silver suppliers and to energy policymakers and regulators, as well as to solar panel manufacturers.
[en] Hard carbons as promising anode materials for Na-ion batteries (NIBs) have captured extensive attention because of their low operation voltage, easy synthesis process, and competitive specific capacity. However, there are still several disadvantages, such as high cost and low initial coulombic efficiency, which limit their large-scale commercial applications. Herein, pine nut shells (PNSs), a low-cost biomass waste, are used as precursors to prepare hard carbon materials. Via a series of washing and heat treatment procedures, a pine nut shell hard carbon (PNSHC)-1400 sample has been obtained and delivers a reversible capacity of around 300 mAh/g, a high initial coulombic efficiency of 84%, and good cycling performance. These excellent Na storage properties indicate that PNSHC is one of the most promising candidates of hard carbon anodes for NIBs. (rapid communication)
[en] A formal analogy between the Friedmann equation of relativistic cosmology and models of convective–radiative cooling/heating of a body (including Newton’s, Dulong-Petit’s, Newton-Stefan’s laws, and a generalization) is discussed. The analogy highlights Lagrangians, symmetries, and mathematical properties of the solutions of these cooling laws.
[en] It is shown that the familiar Larmor’s formula or its relativistic generalization, Liénard’s formula, widely believed to represent the instantaneous radiative losses from an accelerated charge, are not compatible with the special theory of relativity (STR). It is also shown that energy-momentum conservation is violated in all inertial frames when we compute the instantaneous rate of loss of kinetic energy and momentum of the radiating charge in accordance with Larmor’s/Liénard’s formulation. It is emphasized that one should clearly distinguish between the electromagnetic power going as radiation into space and the instantaneous loss of mechanical power by the charge. In literature both powers are treated as not only equal but almost synonymous; the two need not be the same, however. It is pointed out that a mathematical subtlety in the applicability of Poynting’s theorem seems to have been overlooked in the text-book derivation of Larmor’s formula, where a proper distinction between ‘real’ and ‘retarded’ times was not maintained. This has led to some century-old apparent anomalies, including the mysterious Schott energy, which happens to be nothing but merely a change in self-field energy of the charge between retarded and real times. (letter)
[en] The molecular R-matrix formalism is used to calculate bound and continuum states of the CH molecule. Potential energy curves for the bound states of doublet and quartet symmetry are obtained for an extended range of inter nuclear distances between 1–9 a.u. Resonance positions and widths for low-lying Feshbach resonances are also obtained for states with doublet symmetry. These resonances and their continuation as bound states below the CH+ ion ground state are used to construct dissociative states which cross the ground state of the CH+ ion. Several dissociative states of , and symmetry, that were hitherto unknown, have been found and are expected to be useful for other collisional calculations, in particular, for the dissociative recombination of the CH+ ion. (paper)
[en] Ground state properties for Mg isotopes, including binding energies, one- and two-neutron separation energies, pairing energies, nuclear matter radii and quadrupole deformation parameters, are obtained from the selfconsistent relativistic mean field(RMF) model with the pairing correlations treated by a shell-mode-like approach(SLAP), in which the particle-number is conserved and the blocking effects are treated exactly. The experimental data, including the binding energies and the one- and two-neutron separation energies, which are sensitive to the treatment of pairing correlations and block effects, are well reproduced by the RMF + SLAP calculations. (authors)
[en] As much wind power is connected to the power system, the accommodation of the wind power in the power grids becomes a huge challenge to the operation model of China’s power system. Releasing and improving the flexibility of the power system will be necessary and important to enable the accommodation of power generated with renewable energy sources, which is connected to the power grids on a large scale and accounts for a high proportion. The paper, with North Hebei as an example, discusses the relationship between the demand for the flexibility of thermal power units and the accommodation of wind power. This paper further analyzes the demand for peak load regulation in North Hebei at both the present and the future as well as the characteristics of power sources in the power grids of North Hebei and the technical potential of power generation. It also compares the quantity of curtailed power before and after the flexibility-oriented transformation of thermal power units in North Hebei and calculates the minimum technical output of thermal power under different levels of accommodation of wind power. The research shows that the peak load regulating resources in the power grids of North Hebei boast huge potential, but in the long term, to achieve the objective of a 10% curtailment rate of power generated with renewable energy sources, the minimum technical output of condensing units must be lower than the internationally advanced level of 25%. So, it is difficult to fulfill the said objective solely relying on the strengthened transformation of generating units. To reach the level of 5% curtailment rate of power generated with renewable energy sources, the minimum technical output must achieve breakthrough improvement, which requires continuous technological innovation and power flexibility in close coordination.