A consistent interpretation of the Karmen anomaly

The Karmen anomaly can be interpreted as being due to a heavy neutrino of mass around 137 MeV produced in $\pi_{e 2}$ decays. This interpretation is consistent with the present limits on the couplings of such an object.Comment: 11pages, 4figures, Te

Mechanical properties characterization of composite sandwich materials intended for space antenna applications

The composite materials proposed for use in the Advanced Communications Technology Satellite (ACTS) Program contains a new, high modulus graphite fiber as the reinforcement. A study was conducted to measure certain mechanical properties of the new fiber-reinforced material as well as of a composite-faced aluminum honeycomb sandwich structure. Properties were measured at -157, 22, and 121 C. Complete characterization of this material was not intended. Longitudinal tensile, picture-frame shear, short-beam shear, and flexural tests were performed on specimens of the composite face-sheet materials. Unidirectional, cross-plied, and quasi-isotropic fiber composite ply layup designs were fabricated and tested. These designs had been studied by using NASA's Integrated Composite Analyzer (ICAN) computer program. Flexural tests were conducted on (+/- 60/0 deg) sub s composite-faced sandwich structure material. Resistance strain gages were used to measure strains in the tensile, picture-frame, and sandwich flexural tests. The sandwich flexural strength was limited by the core strength at -157 and 22 C. The adhesive bond strength was the limiting factor at 121 C. Adhesive mechanical properties are reflected in sandwich structure flexural properties when the span-to-depth ratio is great enough to allow a significant shear effect on the load-deflection behavior of the sandwich beam. Most measured properties agreed satisfactorily with the properties predicted by ICAN

A search for energy deposition by neutrinos in matter

An exploratory search for an anomalous energy deposition by neutrinos in a germanium crystal was performed in the CERN high energy neutrino beam. No signal was found and a limit is set at a level of about 10^-12 of the normal dE/dx for a minimum ionizing particle.Comment: 7 pages, 3 figures Paper accepted by Physics Letters B on March 4th, 199

Styrene-terminated polysulfone oligomers as matrix material for graphite reinforced composites: An initial study

Styrene terminated polysulfone oligomers are part of an oligomeric class of compounds with end groups capable of thermal polymerization. These materials can be used as matrices for graphite reinforced composites. The initial evaluation of styrene terminated polysulfone oligomer based composites are summarized in terms of fabrication methods, and mechanical and environmental properties. In addition, a description and evaluation is provided of the NASA/Industry Fellowship Program for Technology Transfer

A revision of the genus Bougainvillia (Anthomedusae)

Os autores fizeram uma revisão do gênero Bougainvillia, incluindo todas as espécies descritas sob esse nome e todas aquelas realmente pertencentes a esse gênero, anteriormente descritas sob outros nomes. De cada espécie é dada uma lista de sinônimos a mais completa possível, assim como uma descrição detalhada. As espécies válidas são reunidas numa tabela sinótica com os dados que foi possível reunir para cada espécie. Estabelecida a sinonímia na base dos caracteres morfológicos, foi estudada a zoogeografia do gênero. Tudo indica ser B. ramosa a forma simples primitiva da qual derivaram as demais espécies. Desta forma, ou de outra próxima a ela, teria derivado um grupo de espécies de águas temperadas com certas características morfológicas comuns a todas, e, afora uma que é do Japão, habitantes do Atlântico ou mares adjacentes. Um segundo grupo de espécies teria evoluído em águas frias árticas ou boreais e antárticas, também com caracteres morfológicos em comum. Por fim, um terceiro grupo de espécies teria evoluído em águas tropicais tanto do Atlântico como do Pacífico, apresentando, igualmente, características morfológicas em comum. Considerando o número de espécies e sua distribuição, o gênero Bougainvilia aparece como um gênero inicialmente atlântico, havendo apenas duas espécies distribuídas exclusivamente no Pacífico ou Indo-Pacífico

Autoclavable addition polyimides for 371 C composite applications

Studies were conducted to improve the thermo-oxidative stability (TOS) of PMR type polyimides by the substitution of para-aminostyrene (PAS) for the nadic ester endcap in second generation PMR polyimides (PMR-2). The nadic endcap which provides the PMR polyimides with their relative ease of fabrication, both by limiting the molecular weight of the prepolymer and by undergoing the final addition cure without volatiles, is also the weak link with regard to TOS. A polyimide formulated with PAS endcaps, called V-CAP, utilizes a two step reaction sequence similar to that of the PMR polyimides and can be easily autoclave molded into low void composite materials. Resin studies included two formulations of both PMR-2 and V-CAP, corresponding to n=9 and n=14 prepolymer stoichiometry. Unidirectional reinforced T40R graphite fiber laminates were fabricated from each of the resins was post-cured in either air at 385 C or nitrogen at 400 C. Composite specimens were aged in air at 371 C and mechanical properties were measured at 371 C before and after exposure

Diagnosis and endovascular treatment of an internal mammary artery injury

Internal mammary artery (IMA) disruption after blunt chest trauma is rare. In some instances, it may occur after mild chest trauma with minor external physical findings. However, prompt diagnosis and treatment are necessary, as it can be associated with vascular and parenchymal injuries. We report a case of blunt chest trauma resulting in a sternal fracture associated with an IMA injury, active anterior mediastinal bleeding, bilateral lung contusions, and a left hemothorax. It was successfully treated by selective embolization to the left IMA branch and chest tube placement

Mediastinitis and sternal prosthesis infection successfully treated by minimally invasive omental flap transposition

Purulent mediastinitis is a possible serious complication after mediastinal surgery. We report the case of a localized sternal plasmocytoma treated by sternectomy and prosthetic repair, who needed a second surgery for a fistulizing mediastinitis. Five months earlier, in another Hospital, the patient underwent sternal resection and reconstruction with a “sandwich” prosthesis (Methyl-methacrylate and Marlex mesh). Suppurative mediastinitis occurred and septic shock resolution was observed after the spontaneous opening of a mediastinal cutaneous fistula. After referring to our Unit the patient underwent extensive local and systemic preparation and nutritional support; the infected prosthesis was then removed and the gap filled by a laparoscopically-prepared omental flap. Adequate preoperative management, removal of any infected material and minimally invasive omental flap transposition allowed the successful treatment of this life-threatening condition