Space radiation resistant transparent polymeric materials

A literature search in the field of ultraviolet and charged particle irradiation of polymers was utilized in an experimental program aimed at the development of radiation stable materials for space applications. The rationale utilized for material selection and the synthesis, characterization and testing performed on several selected materials is described. Among the materials tested for ultraviolet stability in vacuum were: polyethyleneoxide, polyvinylnaphthalene, and the amino resin synthesized by the condensation of o-hydroxybenzoguanamine with formaldehyde. Particularly interesting was the radiation behavior of poly(ethyleneoxide), irradiation did not cause degradation of optical properties but rather an improvement in transparency as indicated by a decrease in solar absorptance with increasing exposure time

Fuels and chemicals from biomass using solar thermal energy

The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry

Airborne observations of electric fields around growing and decaying cumulus clouds

Airborne electric field data were gathered in an atmospheric electrification study near Cape Canaveral, FL. A Learjet 36A was instrumented with eight electric field meters (mills) and five different particle probes. The local electric field enhancements at each field mill site were determined under lab conditions and verified using in-flight data. The overdetermined system of eight equations (one for each field mill) was solved using a weighted least squares algorithm to compute the magnitude and direction of the ambient electric field. The signal processing system allowed the measured data to be expressed in terms of earth coordinates, regardless of the attitude of the aircraft. Thus, it was possible to take maximum advantage of the Learjet's speed and maneuverability in studying the electric field structure in the vicinity of the clouds. Data gathered while circling just outside the boundary of a growing cumulus cloud show a nonsymmetric pattern of electric field strength. Field intensity grew rapidly over a period of less than 10 minutes. The observed direction of the ambient electric field vector can be explained by an ascending motion of the charge centers of a classic tripole model of a thunderstorm

Investigation of space radiation effects in polymeric film-forming materials

The literature search in the field of ultraviolet radiation effects that was conducted during the previous program, Contract No. NAS1-12549, has been expanded to include the effects of charged particle radiation and high energy electromagnetic radiation. The literature from 1958 to 1969 was searched manually, while the literature from 1969 to present was searched by using a computerized keyword system. The information generated from this search was utilized for the design of an experimental program aimed at the development of materials with improved resistance to the vacuum-radiation environment of space. Preliminary irradiation experiments were performed which indicate that the approaches and criteria employed are very promising and may provide a solution to the challenging problem of polymer stability to combined ultraviolet/high energy radiation

Factores de nacionalización : nacionalismo, sociedad civil y prácticas culturales

Es común leer en la bibliografía especializada que la nación es construida tanto desde arriba como desde abajo, que es una idea y un proyecto pero también un sentimiento. Al mismo tiempo, se viene destacando cada vez más la importancia que tienen ciertos factores culturales en la construcción y reproducción del nacionalismo. Este artículo sigue estas líneas de reflexión y contribuye al debate sobre la nacionalización, enriqueciendo la perspectiva historiográfica con las aportaciones de los trabajos comparativos entre naciones desde una metodología cualitativa entre historia, sociología, antropología, psicología social y ciencias políticas. El objetivo es pensar desde los casos del Quebec y Cataluña los aspectos culturales del nacionalismo, los factores de nacionalización, la socialización y el rol de las prácticas culturales para entender un proceso clave del nacionalismo: la nacionalización.Sovint es llegeix a la bibliografia especialitzada que la nació és construïda tant des de dalt com des de baix, que és una idea i un projecte, però també un sentiment. Al mateix temps, es destaca cada cop més la importància que tenen certs factors culturals en la construcció i reproducció del nacionalisme. Aquest article segueix aquestes línies de reflexió i contribueix al debat sobre la nacionalització, tot enriquint la perspectiva historiogràfica amb les aportacions dels treballs comparatius entre nacions des d'una metodologia qualitativa entre història, sociologia, antropologia, psicologia social i ciències polítiques. L'objectiu és pensar des dels casos del Quebec i Catalunya els aspectes culturals del nacionalisme, els factors de nacionalització, la socialització i el rol de les pràctiques culturals per entendre un procés clau del nacionalisme: la nacionalització.Contemporary studies on nationalism emphasize that the nation is built both from above and from below. The nation is an idea and a project but also a national feeling. At the same time, the importance of cultural factors in the construction and reproduction of nationalism has been highlighted. Following this perspective, this article aims to collaborate in the debate on nationalization, enriching the historiographical perspective with the contributions of the comparative studies between nations without state from a qualitative methodology between History, Sociology, Anthropology and Political science. Taking into account the cases of Catalonia and Quebec, the main objective is to think about the cultural aspects of nationalism, the factors involved in the nationalization process, the socialization and the role of cultural practices to understand a key process of nationalism, that is to say nationalization

Fundamental investigation of ultraviolet radiation effects in polymeric film-forming materials

A literature search from 1958 to present was conducted on the effect of ultraviolet radiation on polymeric materials, with particular emphasis on vacuum photolysis, mechanisms of degradation, and energy transfer phenomena. The literature from 1958 to 1968 was searched manually, while the literature from 1968 to present was searched by using a computerized keyword system. The primary objective was to provide the necessary background information for the design of new or modified materials with improved stability to the vacuum-radiation environment of space

Application of the Laser to Electric Propulsion

Illumination of a metallic surface with focused light from a ruby laser has been shown to produce very high density ion emission, the ionized particles being emitted with substantial initial velocities. Ion currents of several amperes and electron current of hundreds of amperes have been obtained from a surface disc less than 0.020 in diameter. Ion velocities have been measured to be over 4 kilometers per second as emitted, and changed very slowly with changes in laser energy applied to the emitter. Estimates of emitter temperature and plasma density together with electrical measurements of currents and voltages indicate a highly ionized plasma. Mass spectrometer measurements verified that only singly charged atoms were being formed and that ionization of the emitter was over 99 percent complete. These findings suggest that the laser excited emission technique should find favorable application to two types of thrustors. In one type the impulse caused by the relatively high initial velocity of the emitted particles would be used directly; in the second, the high density relatively monoenergetic and highly ionized plasma would be used as an ion or plasma source in an accelerator type thrustors thus obtaining higher ejection velocities and consequent higher values of specific impulse. The experimental results show that thrusts of about 25 millipounds were produced with 196 watts per millipound power consumption. The specific impulse in the direct thrustor example cited was about 600 seconds. When used as an ion source, several amperes of ion current can be obtained at ionization efficiencies of 600 ev per ion when only the laser is used. The energy required for ion production was found to be as low as 30 ev/ion when ionization was enhanced by the external circuit. Thrust and specific impulse in this case are controlled by the accelerating potentials selected for a given engine. The laser excited emission process is inherently free of standby or warmup power requirements; therefore, the cycling of thrustors using this technique could be predicated exclusively on thrust requirements and on the desired precision of control -without penalty of added power consumption, or equipment malfunction caused by fast cycling. A program to establish the applicability of the laser stimulated emission technique to thrustors and to obtain data for design and evaluation of such thrustors is currently being performed under NASA contract NAS 3-5919

«Do you (really) believe in evil?». Psycho, la serialità televisiva e il suo spettatore

Even if the influence exercised by Hitchcock on the cinema is widely known, it has been largely disregarded by scholars, especially in comparison to the uncountable studies devoted to dissect his own movies. Hitchcock’s influence on television has been even more disregarded. This essay draws on the case study involving Psycho (1960) to enlighten a few radical changes to which intertextuality in the television seriality underwent in the past thirty years. In fact, the classical seriality and the most recent one (usually referred to as the new seriality of quality television) have handled the intertextual relationship in very different ways. The selection of the contents offered by the model is different: indeed, difficult topics and issues, such as serial killing, mental illness and queer sexuality, as well as the performative side of gender, were hardly suitable for the classical seriality. More importantly, it is the conception of the viewer and of his/her habits that changed considerably, so much so to influence the conception and form of series themselves.L’influenza esercitata da Hitchcock sul cinema è un dato tanto notorio quanto sottovalutato dagli studi. Ancora di più lo è la sua influenza sulla televisione. Questo saggio utilizza un esempio significativo – quello che coinvolge il film Psycho (Psyco, 1960) – per mettere in luce alcuni mutamenti radicali subiti dalla gestione  dell’intertestualità nel contesto dell’evoluzione subita dalla serialità televisiva negli ultimi trent’anni. Sensibilmente diverse appaiono infatti le modalità di tale gestione da parte della serialità cosiddetta classica e di quella più recente, variamente definita come ‘nuova’ o ‘di qualità’. Cambia altresì la selezione operata sul complesso materiale offerto dal modello, il quale deve la sua fortuna a intuizioni relative a questioni complesse da affrontare per la serialità classica, come l’intreccio tra morte, instabilità mentale e sessualità eteroclita, o come il carattere performativo del gender. Si metterà infine in luce come a mutare, al fondo, sia la concezione dello spettatore e delle sue prassi di visione, che risultano essere molto diverse tra le due forme di serialità e che incidono in modo radicale sulla loro scrittura e sulla loro concezione formale e strutturale

Cattolici, cinema e omosessualità : il «turpe vizio» dalla rimozione al panico morale

Il saggio ricostruisce lo sviluppo del tentativo, da parte della cultura cattolica, di gestire la rappresentazione dell\u2019omosessualit\ue0 nell\u2019immediato dopoguerra ambendo a preservare la rimozione totale gi\ue0 applicata sotto il fascismo. Utopia dalla quale si trova per\uf2 a dover recedere a cavallo tra anni \u201950 e anni \u201960, a causa tanto della reazione di diverse anime della cultura laica quanto di un\u2019autonoma e pi\uf9 moderata gestione dell\u2019argomento da parte della DC.The essay traces the development of the way in which the catholic culture tried to handle the representation of homosexuality in the after-war, aiming at removing it completely as during Fascism. This utopian effort fails between the late 1950s and early 1960s both because of the reaction of the laic culture and because Christian Democrats chose to manage it in a different a more moderate way