521 research outputs found
Pensieri oggettivi
Moving from a critical discussion of some background assumptions of the Hegel-Renaissance within Anglo-American philosophy, this paper focuses on some crucial points of Hegel’s theory of objective thought and on their relation to Hegel’s philosophical project. Focusing on Hegel’s theory of objective thought is essential to define the position of the Hegelian philosophy within the debate between idealism and realism. That theory determines the Concept as the system of epistemic categories and, at the same time, as the system of ontological structures. Thereby, it allows Hegel to hold that we have a direct epistemic access to the movement of reality. This movement is a process of determination carried out by the ontological structures of the Concept. This process determines states of affairs as possible contents of thought. There is no gap between thought and world. In this way Hegel’s direct epistemological realism opens the possibility that an objective-constraint (i.e., a constraint which is external to thought as a mental activity), is a rational-constraint as well. The paper gives an account of the Hegelian theory of truth as co-implication of truth in ontological sense and propositional truth.
The latter is interpreted along the lines of an identity theory of truth, i.e. as identity between the content of a judgment and the object. The Hegelian theory of truth, conceived in this way, on the basis of the identity between forms of the cognizing subject and forms of reality, and so based on the ontological notion of truth, makes possible to state within the framework of Hegel’s philosophy the ticklish question of the relation between philosophy and common sense. Unlike the retrieval of a second naivety gained by means of philosophical therapy à la Putnam or McDowell, the Hegelian philosophy proposes a rationally responsible reappropriation of our theoretical and practical relationships with natural and social reality, in the spirit of a constructive, systematic philosophy
Pairs in involution
Pairs in involution are a Hopf algebraic structure with applications to category theory, cyclic homology and knot theory. In the present dissertation we will answer the question whether every finite-dimensional Hopf algebra admits such pairs, construct and investigate their categorical analogues, and develop, based on our previous findings, the theory of pairs in involutions for Hopf monads
CAMIEM: Compact Additively Manufactured Innovative Electric Motor
New manufacturing methods are needed to obtain innovative electric motor designs that have much higher power densities and/or efficiencies compared to the current state-of-the-art. Additive manufacturing offers the potential to radically change motor designs so that they have compact designs, multi-material components, innovative cooling, and optimally designed and manufactured components. New component designs enabled by additive manufacturing technologies have been designed and were fabricated to include the housing, rotors, stator cooling ring, a direct printed stator, and a wire embedded stator. The new components were integrated into the motor and tested evaluate the performance gains in comparison to the baseline electric motor configuration. Partners on the sub-project include NASA GRC, NASA LaRC, NASA AFRC, LaunchPoint Technologies, and the University of Texas El Paso
Development and Characterization of the Bonding and Integration Technologies Needed for Fabricating Silicon Carbide Based Injector Components
Advanced ceramic bonding and integration technologies play a critical role in the fabrication and application of silicon carbide based components for a number of aerospace and ground based applications. One such application is a lean direct injector for a turbine engine to achieve low NOx emissions. Ceramic to ceramic diffusion bonding and ceramic to metal brazing technologies are being developed for this injector application. For the diffusion bonding technology, titanium interlayers (coatings and foils) were used to aid in the joining of silicon carbide (SiC) substrates. The influence of such variables as surface finish, interlayer thickness, and processing time were investigated. Electron microprobe analysis was used to identify the reaction formed phases. In the diffusion bonds, an intermediate phase, Ti5Si3Cx, formed that is thermally incompatible in its thermal expansion and caused thermal stresses and cracking during the processing cool-down. Thinner interlayers of pure titanium and/or longer processing times resulted in an optimized microstructure. Tensile tests on the joined materials resulted in strengths of 13-28 MPa depending on the SiC substrate material. Nondestructive evaluation using ultrasonic immersion showed well formed bonds. For the joining technology of brazing Kovar fuel tubes to silicon carbide, preliminary development of the joining approach has begun. Various technical issues and requirements for the injector application are addressed
Total and Nonresidual Concentrations of Selected Elements in Two Soil Series on the Island of Hawaii
Thirty Aridisol soil samples of the Kawaihae soil series on the
dry, leeward, northwestern side of the island of Hawaii and 13 Histosol samples
of the Papai series on the wet, windward, eastern side of the island were subjected
to (1) complete dissolution by a mixture ofHN03, HCl, and HF to determine
total concentrations of Co, Cr, Cu, Fe, Mn, Ni, and Zn and (2) extraction of these
metals by shaking 10 g soil: 100 mL 0.5M HCl solutions for 16hr to determine
nonresidual concentrations. Analyses were performed mainly by flame and
electrothermal atomic absorption spectrophotometry. Loss on ignition (LOI)
and soil pH were also determined.
Total metal concentrations, quantity extracted, LOI, and soil pH were analyzed
statistically. Compared to the Histosol, the Aridisol samples typically contain
more Co, Cr, Fe, and Mn, less Cu, similar concentrations of Ni and Zn, and
have less LOI and higher pH. The Aridisol exhibits a high degree of correlation
between total Cr and Ni, while a strong negative correlation occurs between Cu,
Mn, Co, and Fe individually with LOI in the Histosol. The mean concentrations
of these metals in both soils are significantly greater than those which occur in
soils of the conterminous United States.
The effectiveness of extraction by the acid solution, as measured by the
percentage of metal extracted, is approximately Mn > Co > Cu > Cr > Fe >
Zn - Ni for the Aridisol and Cu - Zn > Co - Mn > Fe - Ni > Cr for the
Histosol; the difference is attributed to weathering under different climatic conditions.
The latter soils exhibit a higher degree of correlation for percentages of
metals extracted among the various metals and with LOI
NASA Subsonic Rotary Wing Project - Structures and Materials Discipline
The Structures & Materials Discipline within the NASA Subsonic Rotary Wing Project is focused on developing rotorcraft technologies. The technologies being developed are within the task areas of: 5.1.1 Life Prediction Methods for Engine Structures & Components 5.1.2 Erosion Resistant Coatings for Improved Turbine Blade Life 5.2.1 Crashworthiness 5.2.2 Methods for Prediction of Fatigue Damage & Self Healing 5.3.1 Propulsion High Temperature Materials 5.3.2 Lightweight Structures and Noise Integration The presentation will discuss rotorcraft specific technical challenges and needs as well as details of the work being conducted in the six task areas
Enabling Additive Manufacturing Technologies for Advanced Aero Propulsion Materials & Components
Additive manufacturing (AM) technologies are enabling for advanced high performance, propulsion component designs in electric motors1-2 and turbine engine systems in future electrified aircraft. AM offers significant benefits over conventional manufacturing to fabricate components that are more compact, lighter weight, geometrically complex, innovatively cooled, integrated, multi-material, and multifunctional. For turbine engine applications, silicon carbide (SiC) based composites are being pursued using binder jetting and laminated object manufacturing (LOM) for components such as shrouds, vanes, and recuperators. For electric motor applications, additive processes are being applied toward optimized component designs to include the housing, rotor, and stators with 3-D printing and wire imbedded coils and with direct printed 3-phase coils. The electrical conductivity of silver conductor coils optimized by evaluating alternate sintering methods and additions of graphene and carbon nanostructures will be presented. Potential benefits of new electric motor components in improving temperature capability, efficiency, and power density for reductions in energy consumption and emissions will be discussed
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