360 research outputs found

    Reusable silica surface-insulation material

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    Material was specifically developed for manufacture of insulating tiles, but it can be molded into other shapes as required. Basic raw materials are high-purity silica fiber, fumed-silica powder, and reagent-grade starch. Only purest materials are used, and care must be taken to avoid contamination during processing

    Fibrous refractory composite insulation

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    A refractory composite insulating material was prepared from silica fibers and aluminosilicate fibers in a weight ratio ranging from 1:19 to 19:1, and about 0.5 to 30% boron oxide, based on the total fiber weight. The aluminosilicate fiber and boron oxide requirements may be satisfied by using aluminoborosilicate fibers and, in such instances, additional free boron oxide may be incorporated in the mix up to the 30% limit. Small quantities of refractory opacifiers, such as silicon carbide, may be also added. The composites just described are characterized by the absence of a nonfibrous matrix

    Silica reusable surface insulation

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    A reusable silica surface insulation material is provided by bonding amorphous silica fibers with colloidal silica at an elevated temperature. The surface insulation is ordinarily manufactured in the form of blocks (i.e., tiles)

    High temperature glass thermal control structure and coating

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    A high temperature stable and solar radiation stable thermal control coating is described which is useful either as such, applied directly to a member to be protected, or applied as a coating on a re-usable surface insulation (RSI). It has a base coat layer and an overlay glass layer. The base coat layer has a high emittance, and the overlay layer is formed from discrete, but sintered together glass particles to give the overlay layer a high scattering coefficient. The resulting two-layer space and thermal control coating has an absorptivity-to-emissivity ratio of less than or equal to 0.4 at room temperature, with an emittance of 0.8 at 1200 F. It is capable of exposure to either solar radiation or temperatures as high as 2000 F without significant degradation. When used as a coating on a silica substrate to give an RSI structure, the coatings of this invention show significantly less reduction in emittance after long term convective heating and less residual strain than prior art coatings for RSI structures

    Reaction cured glass and glass coatings

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    The invention relates to reaction cured glass and glass coatings prepared by reacting a compound selected from the group consisting of silicon tetraboride, silicon hexaboride, other boron silicides, boron and mixtures with a reactive glass frit composed of a porous high silica borosilicate glass and boron oxide. The glassy composites of the present invention are useful as coatings on low density fibrous porous silica insulations used as heat shields and for articles such as reaction vessels that are subjected to high temperatures with rapid heating and cooling and that require resistance to temperature and repeated thermal shock at temperatures up to about 1482C (2700PF)

    Adjustable high emittance gap filler

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    A flexible, adjustable refractory filler is disclosed for filling gaps between ceramic tiles forming the heat shield of a space shuttle vehicle, to protect its aluminum skin during atmospheric reentry. The easily installed and replaced filler consists essentially of a strip of ceramic cloth coated, at least along both its longitudinal edges with a room temperature vulcanizable silicone rubber compound with a high emittance colored pigment. The filler may have one or more layers as the gap width requires. Preferred materials are basket weave aluminoborosilicate cloth, and a rubber compounded with silicon tetraboride as the emittance agent and finely divided borosilicate glass containing about 7.5% B2O3 as high temperature binder. The filler cloth strip or tape is cut to proper width and length, inserted into the gap, and fastened with previously applied drops of silicone rubber adhesive

    [Redacted]: this article categorised [harmful] by the Government

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    In April 2019, the UK Government’s DCMS released its White Paper for ‘Online Harms’, which would establish in law a new duty of care towards users by platforms to be overseen by an independent regulator. Our earlier research outlines how we got to this point, sets out what the White Paper proposes, and criticises its key aspects. Our objections and criticism remain applicable to the UK Government’s Online Safety Bill. The Parliament is now scrutinising the Bill. The House of Lords Report sparked some optimism that the scrutiny could address critical concerns around free speech in particular. The Draft Online Safety Bill Joint Committee Report, however, suggest otherwise. This paper returns to key arguments as to why risk-based regulation and duty of care are not appropriate for policing content and expression online. We focus on the human rights implications of the Bill, in particular, the provider duties to ‘handle’ legal but harmful content. Here, we reemphasise the vague conceptualisation and nature of this harm, as well as the inadequate duties attached to it. We argue that the independence of OFCOM cannot be guaranteed.Effective Protection of Fundamental Rights in a pluralist worl

    Organopolysiloxane Waterproofing Treatment for Porous Ceramics

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    Rigid and flexible porous ceramics, including thermal insulation of a type used on space vehicles, are waterproofed by a treatment which comprises applying an aqueous solution of an organopolysiloxane water-proofing agent having reactive silanol groups to the surface of the ceramic and then heating the treated ceramic to form a waterproofed ceramic. The organopolysiloxane is formed by the hydrolysis and partial condensation of di- and trialkoxyfunctional alkylalkoxysilanes having 1-10 carbon atom hydrocarbyl groups

    Community-Based OT Program Planning: A Virtual Level II Fieldwork Program Developed in Response to the Global Pandemic

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    The purpose of this article is to explain how an occupational therapy (OT) program in a university setting developed a virtual Level II community-based fieldwork program in response to the COVID-19 global pandemic. This virtual fieldwork program, guided by the PRECEDE-PROCEED Planning Model (PPM), was designed to help keep students on track with their academic goals while providing them with experiential learning that would increase their confidence in OT program planning and promote their professional development. Outcome measures for this study consisted of a pre-and post-fieldwork survey that asked participants to rank their self-perceived confidence in five distinct areas of community-based OT program development. Some portions of Section III in the Student’s Evaluation of the Fieldwork Experience (SEFWE) form were also used to examine students’ feedback after participating in this virtual fieldwork program. Retrospective data analysis of pre-post survey results showed improvements in students’ perceived confidence with certain aspects of OT program development in community settings. Within the core function of program development, occupation-based approaches to community-based programs can be used to inform, educate, and empower people and populations about important health issues while simultaneously offering students rich opportunities for professional development and identity. Dissemination of this information can be helpful to other OT professionals who are developing alternate fieldwork programs in response to the pandemic and beyond

    Ancestral roles of the Fam20C family of secreted protein kinases revealed in C. elegans.

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    Fam20C is a secreted protein kinase mutated in Raine syndrome, a human skeletal disorder. In vertebrates, bone and enamel proteins are major Fam20C substrates. However, Fam20 kinases are conserved in invertebrates lacking bone and enamel, suggesting other ancestral functions. We show that FAMK-1, the Caenorhabditis elegans Fam20C orthologue, contributes to fertility, embryogenesis, and development. These functions are not fulfilled when FAMK-1 is retained in the early secretory pathway. During embryogenesis, FAMK-1 maintains intercellular partitions and prevents multinucleation; notably, temperature elevation or lowering cortical stiffness reduces requirement for FAMK-1 in these contexts. FAMK-1 is expressed in multiple adult tissues that undergo repeated mechanical strain, and selective expression in the spermatheca restores fertility. Informatic, biochemical, and functional analysis implicate lectins as FAMK-1 substrates. These findings suggest that FAMK-1 phosphorylation of substrates, including lectins, in the late secretory pathway is important in embryonic and tissue contexts where cells are subjected to mechanical strain
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