Additives to reduce susceptibility of thermosets and thermoplastics to erosion from atomic oxygen

Polymeric materials have many attractive features such as light weight, high strength, and broad applicability in the form of films, fibers, and molded objects. In low earth orbit (LEO), these materials, when exposed on the exterior of the spacecraft, have the serious disadvantage of being susceptible to erosion by atomic oxygen (AO). AO is the most common chemical species at LEO altitudes. AO can be an extremely efficient oxidizing agent as was apparent from the extensive erosion of organic films exposed in STS missions. The mechanism for erosion involves the reaction of oxygen atoms at the surface of the substrate to form small molecular species. The susceptibility of polymeric materials varies with their chemical composition. Films with silicon atoms incorporated in the molecular structures have large coefficients of thermal expansion. This limits their utility. In an alternative approach additives were sought that mix physically and form a protective oxide layer when the film is exposed to AO. A large number of organic compounds containing silicon, germanium, or tin atoms were screened. Most were found to have very limited solubility in the polyetherimide (Ultem) films that were being protected from AO. However, one, bis(triphenyl tin) oxide, (BTO), is miscible in Ultem up to about 25 percent. Films of Ultem polyimide containing up to 25 wt percent BTO were prepared by evaporation of solvent from a solution of Ultem and BTO. The effects of AO on these films were simulated in the oxygen atmosphere of a radio frequency glow-discharge chamber. In the second part of this study, atoms were incorporated in epoxy resins. Experiments are in progress to measure the resistance of films of the cured epoxy to AO in the discharge chamber

Radiation effects on high performance polymers

Polymer matrix materials are candidates for use in large space antennas and space platforms that may be deployed in geosynchronous orbit 22,500 miles above the Earth. A principal concern is the long term effects of an environment that is hostile to organic polymers, including high energy electromagnetic radiation, bombardment by charged particles, and large abrupt changes in temperature. Two polyarylene ethers which might be utilized as models for polymers in space applications were subjected to dosages of 70 keV electrons up to 3.4 x 10 to the 10th power rad. The irradiated films were then examined to determine the effects of the high-energy electrons

Space environmental effects on polymeric materials

Two of the major environmental hazards in the Geosynchronous Earth Orbit (GEO) are energetic charged particles and ultraviolet radiation. The charged particles, electrons and protons, range in energy from 0.1 to 4 MeV and each have a flux of 10 to the 8th sq cm/sec. Over a 30 year lifetime, materials in the GEO will have an absorbed dose from this radiation of 10 to the 10th rads. The ultraviolet radiation comes uninhibited from the sun with an irradiance of 1.4 kw/sq m. Radiation is known to initiate chain sission and crosslinking in polymeric materials, both of which affect their structural properties. The 30-year dose level from the combined radiation in the GEO exceeds the threshold for measurable damage in most polymer systems studied. Of further concern is possible synergistic effects from the simultaneous irradiation with charged particles and ultraviolet radiation. Most studies on radiation effects on polymeric materials use either electrons or ultraviolet radiation alone, or in a sequential combination

The effects of the interaction of polymeric materials with the space environment

Polymeric materials in low earth orbit will be exposed to a harmful environment mainly due to atomic oxygen and ultraviolet radiation. In geosynchronous earth orbit, the major hazards to such materials are energetic charged particles and ultraviolet radiation. The progress of studies on the effects of these hazards on a polyetherimide, a polyimide, and an epoxy adhesive is presented

Shadow Wood Homeowners Association, Inc.; and Gogo Way Trust v. New York Community Bancorp, Inc. (January 28, 2016)

The Court reviewed an appeal from a district court order granting summary judgment to a bank that had lost a condominium in an HOA lien foreclosure sale. The Court held that despite statutory provisions, which seem prohibit overturning an HOA lien foreclosure sale if required recitals are present in the HOA’s trustee deed, there remains a common law power to overturn such foreclosure sales. The Court reaffirmed the principle that, where appropriate, Nevada courts may “grant equitable relief from a defective HOA lien foreclosure sale”—but only when there has been both 1) an inadequate price paid, and 2) fraud or oppression. The Court also vacated the lower court’s ruling and remanded as to both the HOA lien amount and the issues of the parties’ conduct, the buyer’s status, and the equities at stake

William Nathan Baxter v. Dignity Health, et al, 131 Nev. Adv. Op. 76 (September 24, 2015)

The Court considered an appeal from a district court order dismissing a medical malpractice complaint. The Court held that because NRS § 41A.071 creates threshold requirements for bringing medical malpractice suits, it must be construed consistently with the liberal pleading requirements. The Court reversed and remanded

Newman v. State, 132 Nev. Adv. Op. 31 (April 28, 2016)

The Court reviewed two consolidated appeals involving sentencing concerns, which stemmed from a district court judgment revoking probation and a district court judgment of conviction pursuant to a guilty plea. The Court dismissed the appeal of the probation revocation because appellant did not present any cogent arguments on that issue and because she had already been released from the nine-month sentence, rendering the appeal moot. As to the judgment of conviction, the Court affirmed. The Court held that a court may consider a defendant’s status as a pregnant drug addict in sentencing, especially if the status brought up by the defendant, as long as the sentence is also related to the defendant’s crimes. However, the Court made clear that this decision did not imply that a court should consider this status

Prison of the Setting Sun: A Translation of Ono Fuyumi\u27s Rakushō no goku

In this thesis, I have presented my translation of the novella Rakushō no goku (落照の獄) by Ono Fuyumi, preceded by a critical introduction. In this introduction, I have provided brief biographical information about the author, context for the story and its place in the Twelve Kingdoms series of novels, an analysis of the story\u27s use of the death penalty as allegory, and an explanation for some of my choices in the translation. In my introduction, my main purpose was to present the author, who has written multiple best-selling, award-winning novels that have received both popular and critical acclaim, yet has received little notice abroad and even less scholarly attention both in and out of Japan, as a writer meriting further study. To this end, I have used my own translation of Rakushō no goku as a primary example of the depth and value of her work, presenting my reading of the conflict in Rakushō no goku as an oblique criticism of the death penalty in Japan, and attempting to tie the story into a longstanding literary tradition of using the fantastic as allegory in order to comment on and critique contemporary culture