Theoretical studies of radiation effects in composite materials for space use

Tetraglycidyl 4,4'-diamino diphenyl methane epoxy cured with diamino diphenyl sulfone was used as a model compound. Computer programs were developed to calculate (1) energy deposition coefficients of protons and electrons of various energies at different depths of the material; (2) ranges of protons and electrons of various energies in the material; and (3) cumulative doses received by the composite in different geometric shapes placed in orbits of various altitudes and inclination. A preliminary study on accelerated testing was conducted and it was found that an elliptical equitorial orbit of 300 km perigee by 2750 km apogee can accumulate, in 2 years or less, enough radiation dose comparable to geosynchronous environment for 30 years. The local plasma model calculated the mean excitation energies for covalent and ionic compounds. Longitudinal and lateral distributions of excited species by electron and proton impact as well as the probability of overlapping of two tracks due to two charged particles within various time intervals were studied

Basic physical and chemical processes in space radiation effects on polymers

The effects of space ionizing radiation on polymers is investigated in terms of operative physical and chemical processes. A useful model of charged particle impact with a polymer was designed. Principle paths of molecular relaxation were identified and energy handling processes were considered. The focus of the study was on energy absorption and the immediately following events. Further study of the radiation degradation of polymers is suggested

Adsorption of Water on a Cesium Covered SrTiO3 (100) Surface

The paper describes the adsorption of water on cesium covered strontium titanate SrTiO3 (100) surface. The interaction of water with the substrate is investigated by AES, TDS and work function measurements. The results show that water does not dissociate or react with cesium on surface. In contrast when simultaneous adsorption of water and cesium takes place on surface, interaction between the co-adsorbates occurs resulting in cesium oxide formation

Adsorption of Water on a Cesium Covered SrTiO3 (100) Surface

The paper describes the adsorption of water on cesium covered strontium titanate SrTiO3 (100) surface. The interaction of water with the substrate is investigated by AES, TDS and work function measurements. The results show that water does not dissociate or react with cesium on surface. In contrast when simultaneous adsorption of water and cesium takes place on surface, interaction between the co-adsorbates occurs resulting in cesium oxide formation

Management of peripheral facial nerve palsy

Peripheral facial nerve palsy (FNP) may (secondary FNP) or may not have a detectable cause (Bell’s palsy). Three quarters of peripheral FNP are primary and one quarter secondary. The most prevalent causes of secondary FNP are systemic viral infections, trauma, surgery, diabetes, local infections, tumor, immunological disorders, or drugs. The diagnosis of FNP relies upon the presence of typical symptoms and signs, blood chemical investigations, cerebro-spinal-fluid-investigations, X-ray of the scull and mastoid, cerebral MRI, or nerve conduction studies. Bell’s palsy may be diagnosed after exclusion of all secondary causes, but causes of secondary FNP and Bell’s palsy may coexist. Treatment of secondary FNP is based on the therapy of the underlying disorder. Treatment of Bell’s palsy is controversial due to the lack of large, randomized, controlled, prospective studies. There are indications that steroids or antiviral agents are beneficial but also studies, which show no beneficial effect. Additional measures include eye protection, physiotherapy, acupuncture, botulinum toxin, or possibly surgery. Prognosis of Bell’s palsy is fair with complete recovery in about 80% of the cases, 15% experience some kind of permanent nerve damage and 5% remain with severe sequelae

Active nitrogen and oxygen: Enhanced emissions and chemical reactions

Journal URL: http://www.sciencedirect.com/science/journal/0301010

A study of background emissions enhancements in nitrogen afterglows, due to addition of discharged O2, in connection with the reactions {N2 (A 3Σu+, ν) + O(3P}, {O2 (a 1Δg) + N(4S} and {O2 (a 1Δg) + N2

Journal URL: http://www.versita.com/science/chemistry/cej

ADSORPTION KINETICS OF POTASSIUM ON SrTiO3(100)

In this paper, we study the kinetics of potassium adsorption on SrTiO3(100) surface at room temperature. The study took place in UHV using AES, EELS, LEED, TPD, and WF measurements. Potassium grows in two-dimensional islands with maximum coverage of 3.9 × 1014 at/cm2. During adsorption charge transfer from the K-4s to Ti-3d energy level has been observed. No K–O compound has been measured. After heating at 1050 K most of the adsorbed potassium desorbs and the SrTiO3(100) (1 × 1) LEED pattern reappears. There is not any indication of potassium intercalation into the substrate, either at room or at elevated temperature.Potassium, strontium titanate, adsorption, AES, WF, EELS, TPD