Progress in Development of High-Temperature Solar-Selective Coating

Author(s):  
C. E. Kennedy ◽  
H. Price

Improving the properties of the selective coating on the receiver represents one of the best opportunities for improving the efficiency of parabolic trough collectors and reducing the cost of solar electricity. Additionally, increasing the operating temperature above the current operating limits of 400°C can improve power cycle efficiency and reduce the cost of thermal energy storage resulting in reductions in the cost of solar electricity. Current coatings do not have the stability and performance necessary to move to higher operating temperatures. The objective of this effort was to develop new, more-efficient selective coatings with both high solar absorptance (α ≥ 0.96) and low thermal emittance (ε ≤ 0.07 at 400°C) that are thermally stable above 500°C, ideally in air, with improved durability and manufacturability and reduced cost. Using computer-aided design software, we successfully modeled a solar-selective coating composed of materials stable at high temperature that exceeded our property goals. In preparation for characterization of samples of these new coatings, a round-robin experiment was conducted to verify the accuracy of the selective coating reflectance measurements.

Author(s):  
F J Richardson

Success of the design process hinges on efficient communication between the various functions involved. Traditionally this communication has been ‘paper based’ with information passing between sales, design, production and manufacture to describe the complete history of the product. This complex interaction between the functions depends on the availability at each stage of the most up-to-date and accurate information. The paper based system has many shortcomings in this respect particularly the inability of the designer to assess interactively the effect of any changes he may make on the cost, delivery, quality and performance of the product. The use of computer aided design as a central part of the computer aided engineering system allows a company greatly to improve communications during a project by giving the engineer a way of providing accurate information more quickly to each adjacent function while receiving feedback on the effectiveness and suitability of the product in a fraction of the time.


The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.


2021 ◽  
Vol 143 (11) ◽  
Author(s):  
Muhammad Hassan ◽  
Hussain Ahmed Tariq ◽  
Muhammad Anwar ◽  
Talha Irfan Khan ◽  
Asif Israr

Abstract This paper showcases the designing, fabrication, and performance evaluation of 90-deg alpha-type Stirling engine. The diameters of the hot and cold cylinder are 50 mm and 44 mm, respectively, with a stroke length of 70 mm. The computer-aided design (CAD) model is developed by keeping in mind the ease of manufacturing, maintenance, bearing replacements, and lubrication. After fabrication, the engine is tested by heating the hot cylinder with air as a working fluid. The engine delivered peak power of 155 watts at the temperature of 1123 K and 968 K for hot and cold cylinders, respectively. This developed prototype can be commissioned with the solar parabolic concentrator in the future based on the smooth operation while delivering power.


2019 ◽  
Vol 31 ◽  
pp. 103-111 ◽  
Author(s):  
Yu-shan Chang ◽  
Mavis Yi-Ching Chen ◽  
Meng-Jung Chuang ◽  
Chia-hui Chou

Author(s):  
Devarajan Ramanujan ◽  
William Z. Bernstein

VESPER (Visual Exploration of Similarity and PERformance) is a visual analytics system for exploring similarity metrics and performance metrics derived from computer-aided design (CAD) repositories. It consists of (1) a data processing module that allows analysts to input custom similarity metrics and performance metrics, (2) a visualization module that facilitates navigation of the design spaces through coordinated, interactive visualizations, and (3) a report generation module that allows analysts to export lifecycle data of selected repository items as well as the input metrics for further external validation. In this paper, we discuss the need, design rationale, and implementation details for VESPER. We then apply VESPER to (1) sustainability-focused exploration of parts, and (2) exploration of tool wear and surface roughness in machined parts.


2021 ◽  
Vol 111 (2) ◽  
pp. 66-77
Author(s):  
M. Othmani ◽  
K. Zarbane ◽  
A. Chouaf

Purpose: The present work aims to investigate the effect of many infill patterns (rectilinear, line, grid, triangles, cubic, concentric, honeycomb, 3D honeycomb) and the infill density on the mechanical tensile strength of an Acrylonitrile Butadiene Styrene (ABS) test specimen manufactured numerically by FDM. Design/methodology/approach: Computer-Aided Design (CAD) software has been used to model the geometry and the mesostructure of the test specimens in a fully automatic manner from a G-code file by using a script. Then, a Numerical Design of Experiments (NDoE) has been carried out by using Taguchi method and the Analysis of Variance (ANOVA). The tensile behaviour of these numerical test specimens has been studied by the Finite Element Analysis (FEA). Findings: The FEA results showed that a maximal Ultimate Tensile Strength (UTS) was reached by using the ‘concentric’ infill pattern combined with an infill density of 30%. The results also show that the infill pattern and the infill density are significant factors. Research limitations/implications: The low infill densities of 20% and 30% that have already been used in many previous studies, we have also applied it in order to reduce the time of the simulations. Indeed, with high infill density, the simulations take a very excessive time. In an ongoing study, we predicted higher percentages. Practical implications: This study provided an important modelling tool for the design and manufacture of functional parts and helps the FDM practitioners and engineers to manufacture strong and lightweight FDM parts by choosing the optimal process parameters. Originality/value: This study elucidated the effect of various infill patterns on the tensile properties of the test specimens and applied for the first time a NDoE using numerical test specimens created by the mesostructured approach, which considerably minimized the cost of the experiments while obtaining an error of 6.8% between the numerical and the experimental values of the UTS.


2020 ◽  
pp. 030936462094829 ◽  
Author(s):  
Trevor Binedell ◽  
Eugene Meng ◽  
Karupppasamy Subburaj

Background: Upper limb, in particular forequarter amputations, require highly customised devices that are often expensive and underutilised. Objectives: The objective of this study was to design and develop a comfortable 3D-printed cosmetic forequarter prosthetic device, which was lightweight, cool to wear, had an elbow that could lock, matched the appearance of the contralateral arm and was completely free of metal for a specific user’s needs. Study Design: Device design. Technique: An iterative user-centred design approach was used for digitising, designing and developing a functional 3D-printed prosthetic arm for an acquired forequarter amputation, while optimising the fit and function after each prototype. Results: The cost of the final arm was 20% less expensive than a traditionally-made forequarter prostheses in Singapore. The Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) 2.0 survey was administered, with results indicating that the 3D-printed arm was preferred due to its overall effectiveness, accurate size, ease of use and suspension. However, durability had a lower score, and the weight of the arm was 100 g heavier than the user’s current prosthesis. The technique described resulted in a precise fitting and shaped forequarter prosthesis for the user. Using the user’s feedback in the iterations of the design resulted in improved QUEST survey results indicating the device was effective, easy to use, perceived as lighter and more secure than the user’s traditionally-made device. Conclusion: A fully customised cosmetic forequarter prosthesis was designed and developed using digital scanning, computer-aided design modelling and 3D printing for a specific user. These technologies enable new avenues for highly complex prosthetic design innovations.


Author(s):  
J C Rico ◽  
S Mateos ◽  
E Cuesta ◽  
C M Suárez

This paper presents a program for the automatic design of special tools developed under a CAD/CAM (computer aided design/manufacture) system. In particular, the special tools made with standard components have been considered. Since the design of these types of tools was essentially related to the selection of their components, this paper deals with this aspect, insisting upon the selection of those components directly related to the removal of material: the toolholders or cartridges and the inserts. To select these components it is necessary to take into account not only geometrical or technological rules but also economical ones, owing to the high amount of possible components they can select. Consideration of economical aspects required the formulation of the cost equation associated with the use of these types of tools, characterized because their cutting edges coincide with different cutting velocities. Likewise, consideration of economical aspects allows the selection of the optimum cutting conditions and the cutting components to take place at the same time. Some of the geometrical and technological parameters related to the selection of cutting components are automatically identified by the system through an automatic identification of the workpiece profile.


Holzforschung ◽  
2009 ◽  
Vol 63 (3) ◽  
Author(s):  
Peng Li ◽  
Chunping Dai ◽  
Sunguo Wang

Abstract The void variation in a wood-strand composite mat during consolidation was simulated using computer-aided design, finite element analysis, and computer image processing. Compared with prior models, this simulation provided a different and more visual approach to analyzing the mat structure, particularly the void variation during consolidation. The simulated results showed similar trends to the experimental data. The size of voids in the final panel decreased with the panel density and increased with the strand thickness, whereas the relationship between the void size and the strand length was non-linear. The wood-strand density and strand thickness had a much greater effect on the non-linear void variation than the wood strand width and length. The simulated results are beneficial to improve the fundamental understanding of composite processing and performance characteristics.


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