1,816 research outputs found
Parallel implementation of an optimal two level additive Schwarz preconditioner for the 3-D finite element solution of elliptic partial differential equations
Get PDFThis paper presents a description of the extension and parallel implementation of a new two level additive Schwarz (AS) preconditioner for the solution of 3-D elliptic partial differential equations (PDEs). This preconditioner, introduced in Bank et al. (SIAM J. Sci. Comput. 2002; 23: 1818), is based upon the use of a novel form of overlap between the subdomains which makes use of a hierarchy of meshes: with just a single layer of overlapping elements at each level of the hierarchy. The generalization considered here is based upon the restricted AS approach reported in (SIAM J. Sci. Comput. 1999; 21: 792) and the parallel implementation is an extension of work in two dimensions (Concurrency Comput. Practice Experience 2001; 13: 327)
What is a Firm? A Reply to Jean-Philippe Robé
Get PDF© The Author(s), 2021. Published by Cambridge University Press on behalf of Millennium Economics Ltd. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1017/S1744137421000369In his recent book on 'Property, Power and Politics', Jean-Philippe Robé makes a strong case for the need to understand the legal foundations of modern capitalism. He also insists that it is important to distinguish between firms and corporations. We agree. But Robé criticizes our definition of firms in terms of legally recognized capacities on the grounds that it does not take the distinction seriously enough. He argues that firms are not legally recognized as such, as the law only knows corporations. This argument, which is capable of different interpretations, leads to the bizarre result that corporations are not firms. Using etymological and other evidence, we show that firms are treated as legally constituted business entities in both common parlance and legal discourse. The way the law defines firms and corporations, while the product of a discourse which is in many ways distinct from everyday language, has such profound implications for the way firms operate in practice that no institutional theory of the firm worthy of the name can afford to ignore it.Peer reviewe
Laser surface alloying of 316L stainless steel coated with a bioactive hydroxyapatite-titanium oxide composite.
Get PDFLaser surface alloying is a powerful technique for improving the mechanical and chemical properties of engineering components. In this study, laser surface irradiation process employed in the surface modification off 316L stainless steel substrate using hydroxyapatite-titanium oxide to provide a composite ceramic layer for the suitability of applying this technology to improve the biocompatibility of medical alloys and implants. Fusion of the metal surface incorporating hydroxyapatite-titania ceramic particles using a 30 W Nd:YAG laser at different laser powers, 40, 50 and 70% power and a scan speed of 40 mm s(-1) was observed to adopt the optimum condition of ceramic deposition. Coatings were evaluated in terms of microstructure, surface morphology, composition biocompatibility using XRD, ATR-FTIR, SEM and EDS. Evaluation of the in vitro bioactivity by soaking the treated metal in SBF for 10 days showed the deposition of biomimetic apatite
Act quickly, decide later: long latency visual processing underlies perceptual decisions but not reflexive behavior
Get PDFJolij J, Scholte H, Van Gaal S, Hodgson TL, Lamme VAF (2011) Act quickly, decide later: Long latency visual processing underlies perceptual decisions but not reflexive behavior. Journal of Cognitive Neuroscience 23(12), p 3734-3745
Preparation, characterisation and electrochromic property of mesostructured tungsten oxide films via a surfactant templated sol-gel process from tungstic acid
Get PDFA case study in Green chemistry: Developing replacements for CFCs
Get PDFChlorofluorocarbons, CFCs, were developed in the late 1920s for use as safe refrigerant alternatives to sulphur dioxide and ammonia. They were welcomed by industry because of their low toxicity, chemical stability, low flammability, low cost and ease of synthesis. They found wide application as refrigerants, blowing agents, propellants and cleaning agents. Over more than 40 years, applications of CFCs expanded into a wide variety of areas, and grew into a multibillion-dollar industry. Unfortunately, CFCs are not ecologically benign. It became increasingly clear that CFCs were responsible for ozone depletion. In the early 1970s the leading manufacturers of CFCs met to discuss the possible environmental impact of their products.This case study uses a problem based learning approach to take students through the development of replacements for CFCs from the 1970s to today. They investigate the background to the CFC problem and consider data that leads to the decision to investigate possible replacements. They must select and design replacement molecules (HFCs), devise syntheses and then consider the challenge to develop the replacements in a socio-economic and political framework. They also consider the problems posed by existing CFCs, the ‘fridge mountain’ and possible disposal and containment alternatives.The case study brings the story up to date with an investigation of the problems now being associated with HFCs and the search for new alternatives. This activity successfully teaches applied and ‘green’ chemistry via a real life context. The chemistry encountered is of an applied/industrial nature and is set in a socioeconomic context. The influence of political pressures is also brought in when appropriate. Because the activity adopts a problem based approach it is also successful in developing a range of transferable skills, particularly problem solving, teamwork plus verbal and written communication
Fabrication of Insulation Coatings on Additively Manufactured CuCrZr Electrical Windings
Get PDFTo lower the ac losses in electrical machines, additive manufacturing (AM) has been adopted to exploit the geometrical freedom in winding design. However, AM brings about new challenges such as surface roughness and porosity which can create difficulties for post processing of the windings such as applying insulation coatings. The article investigates the influence of surface roughness (profile) of AM-processed CuCrZr as a potential candidate for electrical windings in terms of geometry, surface roughness, porosity, and oxidation on their insulation. The feasibility and characteristics of insulations applied via three processing techniques namely powder, spray, and dip coating are compared. The entire process is quantified via techniques such as computed tomography, surface profilometry, optical microscopy, X-ray photon spectroscopy, and breakdown voltage (BV) at different stages of the coating process. The study also includes coating on a commercial rectangular copper wire as a reference. The initial assessment of coatings concludes that surface roughness and the coating process are both vital determinants for the success of insulating AM components. Basic surface smoothening is needed to get rid of burs and the spray coating technique was the best among others for its capability to produce conformal coating
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