Low cost space power generation

The success of this study has given a method of fabricating durable copolymer films without size limitations. Previously, only compression molded samples were durable enough to generate electrical energy. The strengthened specimens are very long lived materials. The lifetime was enhanced at least a factor of 1,300 in full pyroelectric conversion cycle experiments compared with extruded, non-strengthened film. The new techniques proved so successful that the lifetime of the resultant copolymer samples was not fully characterized. The lifetime of these new materials is so long that accelerated tests were devised to probe their durability. After a total of more than 67 million high voltage electrical cycles at 100 C, the electrical properties of a copolymer sample remained stable. The test was terminated without any detectable degradation to allow for other experiments. One must be cautious in extrapolating to power cycle performance, but 67 million electrical cycles correspond to 2 years of pyroelectric cycling at 1 Hz. In another series of experiments at reduced temperature and electrical stress, a specimen survived over one-third of a billion electrical cycles during nearly three months of continuous testing. The radiation-limited lifetimes of the copolymer were shown to range from several years to millions of years for most earth orbits. Thus, the pyroelectric copolymer has become a strong candidate for serious consideration for future spacecraft power supplies

Comparative Behavior of \u3ci\u3ePyrellia Cyanicolor\u3c/i\u3e (Diptera: Muscidae) on the Moss \u3ci\u3eSplachnum Ampullaceum\u3c/i\u3e and on Substrates of Nutritional Value

(excerpt) Entomophily is commonly associated with flowering plants and their pollen vectors, but also occurs in other groups of plants. Among fungi, several genera of Phallaceae offer food rewards to calliphorid and muscid flies, which inadvertently disperse the fungal spores (Ingold 1964). Bryhn (1897) first noted a relationship between various species ofDiptera and members of the moss family Splachnaceae. The nature of this interaction has been the subject of much speculation (Bequaert 1921, Erlanson 1935, Crum et aI. 1972, Koponen and Koponen 1977), but no experimental evidence has been collected

A robot hand testbed designed for enhancing embodiment and functional neurorehabilitation of body schema in subjects with upper limb impairment or loss.

Many upper limb amputees experience an incessant, post-amputation "phantom limb pain" and report that their missing limbs feel paralyzed in an uncomfortable posture. One hypothesis is that efferent commands no longer generate expected afferent signals, such as proprioceptive feedback from changes in limb configuration, and that the mismatch of motor commands and visual feedback is interpreted as pain. Non-invasive therapeutic techniques for treating phantom limb pain, such as mirror visual feedback (MVF), rely on visualizations of postural changes. Advances in neural interfaces for artificial sensory feedback now make it possible to combine MVF with a high-tech "rubber hand" illusion, in which subjects develop a sense of embodiment with a fake hand when subjected to congruent visual and somatosensory feedback. We discuss clinical benefits that could arise from the confluence of known concepts such as MVF and the rubber hand illusion, and new technologies such as neural interfaces for sensory feedback and highly sensorized robot hand testbeds, such as the "BairClaw" presented here. Our multi-articulating, anthropomorphic robot testbed can be used to study proprioceptive and tactile sensory stimuli during physical finger-object interactions. Conceived for artificial grasp, manipulation, and haptic exploration, the BairClaw could also be used for future studies on the neurorehabilitation of somatosensory disorders due to upper limb impairment or loss. A remote actuation system enables the modular control of tendon-driven hands. The artificial proprioception system enables direct measurement of joint angles and tendon tensions while temperature, vibration, and skin deformation are provided by a multimodal tactile sensor. The provision of multimodal sensory feedback that is spatiotemporally consistent with commanded actions could lead to benefits such as reduced phantom limb pain, and increased prosthesis use due to improved functionality and reduced cognitive burden

EPA Pats Itself on the Back

The Environmental Protection Agency's report to Congress on the benefits and costs of the Clean Air Act from 1990 to 2010 is uninformative and unreliable. It considers no regulatory alternatives, overstates likely benefits and understates costs. Successive reviews under the auspices of EPA's Science Advisory Board and the Office of Management and Budget did not prevent these shortcomings. We recommend that Congress should ask for major reviews of regulatory programs only from entities that are independent of the agencies that administer the programs.Environment, Regulatory Reform

Linearized Gravity in Brane Backgrounds

A treatment of linearized gravity is given in the Randall-Sundrum background. The graviton propagator is found in terms of the scalar propagator, for which an explicit integral expression is provided. This reduces to the four-dimensional propagator at long distances along the brane, and provides estimates of subleading corrections. Asymptotics of the propagator off the brane yields exponential falloff of gravitational fields due to matter on the brane. This implies that black holes bound to the brane have a "pancake"-like shape in the extra dimension, and indicates validity of a perturbative treatment off the brane. Some connections with the AdS/CFT correspondence are described.Comment: 31 pages, harvmac. v2: minor typo and reference corrections. v3: minor corrections to eqs and discussio

"Minsky's Analysis of Financial Capitalism"

In this paper, the authors discuss Minsky's analysis of the evolution of one variety of capitalism--financial capitalism--which developed at the end of the nineteenth century and was the dominant form of capitalism in the developed countries after World War II. Minsky's approach, like those of Schumpeter and Veblen, emphasized the importance of market power in this stage of capitalism. According to Minsky, modern capitalism requires expensive and long-lived capital assets, which, in turn, necessitate financing of positions in these assets as well as market power in order to gain access to financial markets. It is the relation between finance and investment that creates instability in the modern capitalist economy. Financial capitalism emerged from World War II with an array of new institutions that made it stronger than ever before. As the economy evolved, it moved from this more successful form of financial capitalism to the fragile form of capitalism that exists today.

"Fiddling in Euroland as the Global Meltdown Nears"

President Dimitri B. Papadimitriou and Senior Scholar L. Randall Wray argue that the common diagnosis of a "sovereign debt crisis" ignores the crucial role of rising private debt loads and the significance of current account imbalances within the eurozone. Profligate spending in the periphery is not at the root of the problem. Moreover, pushing austerity in the periphery while ignoring the imbalances within the eurozone is a recipe for deflationary disaster. The various rescue packages on offer for Greece will not ultimately solve the problem, say the authors, and a default is a very real possibility. If a new approach is not embraced, we are likely seeing the end of the European Monetary Union (EMU) as it currently stands. The consequences of a breakup would ripple throughout the EMU as well as the shaky US financial system, and could ultimately trigger the next global financial crisis.