Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “MOLD”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15

Shaping Symmetry and Molding Morphology of Triply-Periodic Network Assemblies via Molecular Design and Processing of Block Copolymers

This project aimed to uncover molecular design rules for block copolymer (BCP) assemblies of triply-periodic network (TPN) phases, which are highly sought after, yet elusive, nanostructures for many functional material applications that rely on their combination of symmetry and polycontinuous domain connectivity [R1, R2], such as topological-photonics, supercapacitors and ultrafiltration media. While they have been a target of “bottom up” approaches to nanostructured, hybrid materials, the ability to manipulate the tubular network morphology of TPN assemblies beyond the cubic double-gyroid (DG) phase has advanced relatively little.

36 MATERIALS SCIENCE↗

Exploring the functional performance of a commercial hightemperature photopolymer resin for vat photopolymerized injection molding tools

• Selective photopolymerization of a liquid photocurable resin using ultraviolet (UV) or visible light in discrete layers • Photocurable resins are typically a mixture of monomer(s), oligomer(s), photoinitator(s), and additive(s), when applicable • Recent advances in high-performance resins have made VPP increasingly viable for functional tooling applications

Jones, Haley W. [Savannah River National Laborator↗

Subphotospheric Emission from Short Gamma-Ray Bursts: Protons Mold the Multimessenger Signals

Abstract The origin of the observed Band-like photon spectrum in short gamma-ray bursts (sGRBs) is a long-standing mystery. We carry out the first general relativistic magnetohydrodynamic simulation of an sGRB jet with initial magnetizationσ 0 = 150 in dynamical ejecta from a binary merger. From this simulation, we identify regions along the jet of efficient energy dissipation due to magnetic reconnection and collisionless subshocks. Taking into account electron and proton acceleration processes, we solve for the first time the coupled transport equations for photons, electrons, protons, neutrinos, and intermediate particle species up to close to the photosphere (i.e., up to 1 × 10 12 cm), accounting for all relevant radiative and cooling processes. We find that the subphotospheric multimessenger signals carry strong signatures of the hadronic interactions and their resulting particle cascades. Importantly, the spectral energy distribution of photons is significantly distorted with respect to the Wien one, commonly assumed below the photosphere. Our findings suggest that the bulk of the nonthermal photon spectrum observed in sGRBs can stem from hadronic processes occurring below the photosphere and previously neglected, with an accompanying energy flux of neutrinos peaking in the GeV energy range.

Astronomy & Astrophysics↗

Precision metal molding

Method provides precise alignment for metal-forming dies while permitting minimal thermal expansion without die warpage or cavity space restriction. The interfacing dowel bars and die side facings are arranged so the dies are restrained in one orthogonal angle and permitted to thermally expand in the opposite orthogonal angle.

Townhill, A.↗