Development of ultraviolet rigidizable materials

A series of tests was performed to determine an optimum resin to be used as a UV rigidizable matrix in expandable rigidizable space structures. Commercially available resins including several types of polyesters, epoxies, epoxy-acrylics, an acrylic and a urethane were used as well as a polyester, produced by 3M Company's Solar Laboratory facility, which was found the best from the standpoint of physical properties and ability to be 'B' staged. Two other synthesized materials were also tested, but were not found to be superior to the Solar resin. An optimum fabric for use with the preferred resin was not found; however, the 15 ounce fabric from Solar Laboratories has the best combination of physical properties with respect to handling and processing characteristics. Expansion techniques for tubular structures, 'B' staging of the solar resin, and stowage techniques for up to 5 months were developed. A one meter high tetrahedron preprototype structure was prepared to evaluate and demonstrate stowage, deployment, and rigidization techniques

Studies of new perfluoroether elastomeric sealants

Channel and filleting sealants were developed successfully from cyano and diamidoxime terminated perfluoro alkylene ether prepolymers. The prepolymers were polymerized, formulated and tested. The polymers and/or formulations therefrom were evaluated as to their physical, mechanical and chemical properties (i.e., specific gravity, hardness, nonvolatile content, corrosion resistance, stress corrosion, pressure rupture resistance, low temperature flexibility, gap sealing efficiency, tensile strength and elongation, dynamic mechanical behavior, compression set, fuel resistance, thermal properties and processability). Other applications of the formulated polymrs and incorporation of the basic prepolymers into other polymeric systems were investigated. A cyano terminated perfluoro alkylene oxide triazine was formulated and partially evaluated. The channel sealant in its present formulation has excellent pressure rupture resistance and surpasses present MIL specifications before and after fuel and heat aging

High performance channel injection sealant invention abstract

High performance channel sealant is based on NASA patented cyano and diamidoximine-terminated perfluoroalkylene ether prepolymers that are thermally condensed and cross linked. The sealant contains asbestos and, in its preferred embodiments, Lithofrax, to lower its thermal expansion coefficient and a phenolic metal deactivator. Extensive evaluation shows the sealant is extremely resistant to thermal degradation with an onset point of 280 C. The materials have a volatile content of 0.18%, excellent flexibility, and adherence properties, and fuel resistance. No corrosibility to aluminum or titanium was observed

Homosexuality in Art

Homosexuality in art is nothing new. It has existed for centuries. This paper traces, via relative examples, homosexual themes in art from the ancient Greek vases to the twentieth century. The paper is divided into four sections: Greek Homosexuality, Christian Traditions, 19th and 20th Century Art, and My Work and that of other Artists. Examples from these chapters have been taken and are discussed, with special reference to the titles. In chapter one there is an emphasis on homosexual imagery found on ancient Greek pots, and the almost relaxed way in which the Greeks portrayed and lived with homosexuality. They believed that everyone responded to both homosexual and heterosexual stimuli. The Greeks also stipulated through their imagery, what they considered beautiful in a man. Homosexuality in poetry is also commented on. However, as chapter two illustrates, during the Renaissance period references to homosexuality and masochism were only suggested, and such associations were very carefully disguised for fear of retaliation by the church. This thesis will show that the church\u27s repressive role on sexual expression did not end with the Renaissance, but has had some impact on today\u27s attitudes toward homosexuality and masochism within art. Chapter four discusses the works of twentieth century artists, such as, Charles Demuth, Bellows, Eakins, Freud, and Beardsley. The thesis covers the contemporary period of the author\u27s work in relation to other works by contemporary artists. Topics discussed include: usage of images, figures taken out of their context, and relocated with new identities and unexpected associations. Although the repression has not allowed homosexual art the exposure and acceptance of other forms, it has been, and will continue to be a viable theme for expression in art, and it has shown itself through art in intriguing and very subtle ways

Gauge transformations in the Lagrangian and Hamiltonian formalisms of generally covariant theories

We study spacetime diffeomorphisms in Hamiltonian and Lagrangian formalisms of generally covariant systems. We show that the gauge group for such a system is characterized by having generators which are projectable under the Legendre map. The gauge group is found to be much larger than the original group of spacetime diffeomorphisms, since its generators must depend on the lapse function and shift vector of the spacetime metric in a given coordinate patch. Our results are generalizations of earlier results by Salisbury and Sundermeyer. They arise in a natural way from using the requirement of equivalence between Lagrangian and Hamiltonian formulations of the system, and they are new in that the symmetries are realized on the full set of phase space variables. The generators are displayed explicitly and are applied to the relativistic string and to general relativity.Comment: 12 pages, no figures; REVTeX; uses multicol,fancyheadings,eqsecnum; to appear in Phys. Rev.

Addressing the Safety and Criminal Exploitation of Vulnerable Young People: Before, During and After COVID-19 and Lockdown

This chapter is discussing the intersection of what is arguably an epidemic, and a pandemic, both of which can be fatal. In recent years there has been an epidemic in youth violence and crime, particularly in East London, and in the London Borough of Newham, where knife crime cases and youth knife injuries in particular have been consistently higher than comparator boroughs and London as a whole between 2013 and 2017. The chapter discusses in some detail the pre-pandemic Newham Keeping Safe (hereafter NKS) intervention aimed at vulnerable teenagers, proposing how this type of intervention could be adapted to the changing conditions of COVID-19 restrictions, and exploring the broader psychosocial implications for future interventions that aim to reduce the criminal exploitation of vulnerable young people, as we ‘open up’, or, at least, travel through new sets of changing conditions and restrictions. Such an endeavour requires that we reflect on what future levels of social distancing combined with more digital connections and practices could mean. Future interventions, we argue, need to include a reflection on the complex needs of children and families, and fathom the impact of interventions and their future post-COVID-19

Computed tomography measures of nutrition in patients with end-stage liver disease provide a novel approach to characterize deficits

Aim Patients with cirrhosis and end-stage liver disease (ESLD) develop severe nutrition deficits that impact on morbidity and mortality. Laboratory measures of nutrition fail to fully assess clinical deficits in muscle mass and fat stores. This study employs computed tomography imaging to assess muscle mass and subcutaneous and visceral fat stores in patients with ESLD. Methods This 1:1 case-control study design compares ESLD patients with healthy controls. Study patients were selected from a database of ESLD patients using a stratified method to assure a representative sample based on age, body mass index (BMI), gender, and model for end-stage liver disease score (MELD). Control patients were trauma patients with a low injury severity score (<10) who had a CT scan during evaluation. Cases and controls were matched for age +/- 5 years, gender, and BMI +/- 2. Results There were 90 subjects and 90 controls. ESLD patients had lower albumin levels (p<0.001), but similar total protein levels (p=0.72). ESLD patients had a deficit in muscle mass (-19%, p<0.001) and visceral fat (-13%, p<0.001), but similar subcutaneous fat (-1%, p=0.35). ESLD patients at highest risk for sarcopenia included those over age 60, BMI< 25.0, and female gender. We found degree of sarcopenia to be independent of MELD score. Conclusions These results support previous research demonstrating substantial nutrition deficits in ESLD patients that are not adequately measured by laboratory testing. Patients with ESLD have significant deficits of muscle and visceral fat stores, but a similar amount of subcutaneous fat