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Waste
(2020)
The wide range of factors contributing to wind resource assessment accuracy in complex terrain
(2022)
Laser powder-bed fusion has become one of the most important techniques in additive manufacturing. For guaranteeing the possibility of manufacturing highly specialized and advanced components, currently intensive research is carried out in this field. One area of this research is the material-specific macroscopic anisotropy, which is investigated in our work by comprehensive static mechanical experiments. The material which was tested within this study was the precipitation-hardenable AlSi10Mg alloy, with the focus on installation space orientation. Tensile and compression tests were performed, the results for the Young's modulus in compressive loading exceeded the previously known values of this material in tensile loading and achieved values of up to 79.8 GPa. As a result of this investigation, a chemical spectroscopic analysis was undertaken and from the actual chemical composition, a relative density of 99.86% of the samples was determined.
Our current mobility paradigm increasingly faces economic, ecological, and social limits in urban areas. The aim of this paper is to analyse if a fleet of shared autonomous electric vehicles (AEVs) can meet these challenges while satisfying the current requirements of privately-owned internal combustion engine vehicles (ICEVs). Therefore, analytical models have been developed to simulate and investigate the impacts of mobility behaviour in Berlin and Stuttgart (Germany). The collected data were used to calculate the fleet size, the energy consumption, the emission of particulate matter, nitrogen oxides, and the carbon footprint of different shared AEVs in comparison with privately owned ICEVs. The approach shows that the system of a shared AEV fleet could lower externalities (accident avoidance, traffic jams, free spaces, parking costs and lifetime losses) in cities and generate cost benefits for customers.
The methodology of the approximation and interpretation of thermal desorption spectra (TDS) of hydrogen in some carbon nanostructures and graphite has been developed and applied for such materials.
The methodology is based on a definite approximation by the symmetrical Gaussians of the hydrogen thermal desorption spectra, obtained by using one single heating rate, for carbon materials and nanomaterials, and a definite processing of the Gaussians, in the approximation of the first-order reactions and the second-order ones. It results in determining (with a satisfactory accuracy, for the further physical analysis), from TDS data of one single heating rate, the activation energies and pre-exponential factors of the rate constants of desorption processes corresponding to the main TDS peaks with different temperatures of the maximum desorption rate. The developed methodology contains several successive steps of its implementation, including the use of several “criterions of truth” and the final verification and/or modification of the results, with the help of numerical modeling methods. This technique is not less informative, but much less time-consuming in experimental terms compared to the generally accepted classical Kissinger method, which demands using of several heating rates, and has strict limits of applicability. Furthermore, the methodology allows one to reveal physics and atomic mechanisms of the main desorption processes through thermodynamic analysis of the obtained peak characteristics and comparison with the corresponding independent experimental and theoretical data.
The purpose of such a methodology is to further reveal the weakly studied physics of the main states of hydrogen in carbon materials and nanomaterials, and not the thorough detailed mathematical description of the spectra. For this case, both the large difference and the large spread of the known experimental and theoretical values of the thermodynamic characteristics of the main desorption processes, important for hydrogen storage problems, are also taken into account.
We consider the mixed initial-boundary value problem in the context of the
Moore-Gibson-Thompson theory of thermoelasticity for dipolar bodies. We consider the case of heat conduction with dissipation. Even if the elasticity tensors
are not supposed to be positively defined, we have proven both, the uniqueness
and the instability of the solution of the mixed problem. In the case that the mass
density and the thermal conductivity tensor are positive, we obtain the uniqueness
of the solution using some Lagrange type identities.
Our study is dedicated to a composite, which, in fact, is a mixture of two thermoelastic micropolar bodies. We formulate the mixed initial boundary value problem in this context and define the domain of influence for given data. For any solution of the mixed problem we associate a measure and prove a second-order differential inequality for it. Based on the maximum principle for the heat equation and on the second-order differential inequality, we establish an estimate which proves that the thermal and the mechanical effects, at large distance from the domain of influence, are dominated by an exponential decay.
Background:
Glaucoma, a characteristic type of optic nerve degeneration in the posterior pole of the eye, is a common cause of irreversible vision loss and the second leading cause of blindness worldwide. As an optic neuropathy, glaucoma is identified by increasing degeneration of retinal ganglion cells (RGCs), with consequential vision loss. Current treatments only postpone the development of retinal degeneration, and there are as yet no treatments available for this disability. Recent studies have shown that replacing lost or damaged RGCs with healthy RGCs or RGC precursors, supported by appropriately designed bio-material scaffolds, could facilitate the development and enhancement of connections to ganglion cells and optic nerve axons. The consequence may be an improved retinal regeneration. This technique could also offer the possibility for retinal regeneration in treating other forms of optic nerve ailments through RGC replacement.
Methods:
In this brief review, we describe the innovations and recent developments in retinal regenerative medicine such as retinal organoids and gene therapy which are specific to glaucoma treatment and focus on the selection of appropriate bio-engineering principles, biomaterials and cell therapies that are presently employed in this growing research area.
Results:
Identification of optimal sources of cells, improving cell survival, functional integration upon transplantation, and developing techniques to deliver cells into the retinal space without provoking immune responses are the main challenges in retinal cell replacement therapies.
Conclusion:
The restoration of visual function in glaucoma patients by the RGC replacement therapies requires appropriate protocols and biotechnology methods. Tissue-engineered scaffolds, the generation of retinal organoids, and gene therapy may help to overcome some of the challenges in the generation of clinically safe RGCs.
Metal additive manufacturing of dental prostheses consisting of cobalt−chromium−tungsten (Co−Cr−W) alloys poses an alternative to investment casting. However, metal additive manufacturing processes like Laser Powder‐Bed Fusion (LPBF) can impact the elastic constants and the mechanical anisotropy of the resulting material. To investigate the phase compositions of mechanically different specimens in dependence of their postprocessing steps (e. g. heat treatment to relieve stress), the current study uses X‐ray Diffraction (XRD), Electron BackScatter Diffraction (EBSD), and Transmission Electron Microscopy (TEM) for phase identification. Our studies connect plastic deformation of Remanium star CL alloy with the formation of the hexagonal ϵ‐phase and heat treatment with the formation of the D024‐phase, while partially explaining previously observed differences in Young's moduli.