Design and fabrication of a low-specific-weight parabolic dish solar concentrator

A segmented design and fabrication and assembly techniques were developed for a 1.8 m (6 ft) diameter parabolic concentrator for space application. This design and these techniques were adaptable to a low cost, mass-produced concentrator. Minimal machining was required. Concentrator segments of formed magnesium were used. The concentrator weighed only 1.6 kg sq m (0.32 lbm/sq ft)

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant. Design Requirements Document (DRD)

A description and the design requirements for the 200 MWe (nominal) net output MHD Engineering Test Facility (ETF) Conceptual Design, are presented. Performance requirements for the plant are identified and process conditions are indicated at interface stations between the major systems comprising the plant. Also included are the description, functions, interfaces and requirements for each of these major systems. The lastest information (1980-1981) from the MHD technology program are integrated with elements of a conventional steam electric power generating plant

Numerical and Experimental Analysis of the Influence of Assembling Conditions and the Tolerance of Adapted Implantological Components on the Durability of the Prosthetic Construction

Durable fastening of implant retained prosthetic restorations, consisting of a series of elements, is one of the main factors of successful prosthetic rehabilitation. Clinically observed mechanical problems concerning the above mentioned components are complications that occur most often in the loading phase. The aim of this research was evaluation of the suppleness of the implant- -anti-rotary abutment construction to loosening under the influence of labile mechanical stress. Numerical analysis of resistance based on the finite element analysis (FEA) was used in the initial phase of this research. The actual tests were done with the use of a dynamic mechanical analyser Netzsch DMA 242 and a polarisation microscope equipped with a CCD camera. A series of implants connected with abutments composed of two parts were analysed. The results of initial studies utilizing the finite element analysis (FEA) allowed definition of the spheres of stress concentration. On the basis of in vitro experiments, the investigators evaluated the influence of tolerance of adapted implant-abutment interface fit, as well as the torque used in the assembly of the abutment, on the occurrence of micromovements and loosening of components. The results strongly indicate correlation between the chosen variables and the risk of occurrence of mechanical complications

Coordinating Solvent-Assisted Synthesis of Phase-Stable Perovskite Nanocrystals with High Yield Production for Optoelectronic Applications

Inorganic perovskite nanocrystals (NCs) have shown good potential as an emerging semiconducting building block owing to their excellent optoelectronic properties. However, despite extensive studies on their structure-dependent optical properties, they still suffer severely from chemical and phase instabilities in ambient conditions. Here, we report a facile method for the synthesis of mixed halide inorganic perovskite NCs based on recrystallization in an antisolvent mixture in an ambient atmosphere, at room temperature. We introduced an alcohol-derivative solvent, as a secondary antisolvent in the solvent mixture, which crystallizes at room temperature. This mediates and facilitates the perovskite crystallization, leading to a high chemical yield and stability. We demonstrate that this secondary antisolvent establishes intermolecular interactions with lead halide salt, which successfully stabilizes the γ-dark phase of perovskite by encapsulating NCs in a solution and thin film. This allows us to produce concentrated NC solutions with a photoluminescence quantum yield of 70%. Finally, we fabricate CsPbI2Br NCs (optical bandgap 1.88 eV) solar cells, which showed a stabilized photovoltaic performance in ambient conditions, without encapsulation, showing a Voc of 1.32 V