Study of orifice fabrication technologies for the liquid droplet radiator

Eleven orifice fabrication technologies potentially applicable for a liquid droplet radiator are discussed. The evaluation is focused on technologies capable of yielding 25-150 microns diameter orifices with trajectory accuracies below 5 milliradians, ultimately in arrays of up to 4000 orifices. An initial analytical screening considering factors such as trajectory accuracy, manufacturability, and hydrodynamics of orifice flow is presented. Based on this screening, four technologies were selected for experimental evaluation. A jet straightness system used to test 50-orifice arrays made by electro-discharge machining (EDM), Fotoceram, and mechanical drilling is discussed. Measurements on orifice diameter control and jet trajectory accuracy are presented and discussed. Trajectory standard deviations are in the 4.6-10.0 milliradian range. Electroforming and EDM appear to have the greatest potential for Liquid Droplet Radiator applications. The direction of a future development effort is discussed

Fabrication of passive elements using ink-jet technology

Abstract Introduction MicroJet technology is an emerging technology developed to meet the needs of next generation electronic and opto-electronic packaging solutions in a data-driven manner. It is based on piezoelectric demand-mode ink jet printing technology that is capable of generating and placing droplets of polymers, solder, organometallic and metal nanoparticle solutions, 25-125µm in diameter, at rates up to 4,000 per second. As performance, real estate and overall system costs become critical in manufacture of printed circuit boards, ink jet printing is becoming an increasingly attractive material deposition method. Ink jet based deposition is a low cost (no tooling required), noncontact, flexible & data driven (no masks or screens are required since the print pattern is created directly from CAD information and stored digitally), and environmentally friendly (it is an additive process with no chemical waste)

Laser-initiated decomposition products of indocyanine green (ICG) and carbon black sensitized biological tissues

Organic dyes have found increasing use a s sensitizers in laser surgical procedures, due to their high optical absorbances. Little is known, however, about the nature of the degradation products formed when these dyes are irradiated with a laser. Previous work in our laboratories has shown that irradiation of polymeric and biological tissues with CO2 and Nd:YAG lasers produces a host of volatile and semivolatile by-products, some of which are known to be potential carcinogens. This work focuses on the identification of the chemical by-products formed by diode laser and Nd:YAG laser irradiation of indocyanine green (ICG) and carbon black based ink sensitized tissues, including bone, tendon and sheep\u27s teeth. Samples were mounted in a 0.5-L Pyrex sample chamber equipped with quartz optical windows, charcoal filtered air inlet and an outlet attached to an appropriate sample trap and a constant flow pump. By-products were analyzed by GC/MS and HPLC. Volatiles identified included benzene and formaldehyde. Semi-volatiles included traces of polycyclic aromatics, arising from the biological matrix and inks, as well as fragments of ICG and the carbon ink components. The significance of these results will be discussed, including the necessity of using appropriate evacuation devices when utilizing lasers for surgical procedures

Societal Adaptation to Decadal Climate Variability in the United States

The search for evidence of decadal climatic variability (DCV) has a very long history. In the past decade, a research community has coalesced around a series of roughly biennial workshops that have emphasized description of past DCV events; their causes and their teleconnections responsible for droughts, floods, and warm and cold spells around the world; and recently, the predictability of DCV events. Researchers studying climate change put great emphasis on prospective impacts, but the DCV community has yet to do so. To begin rectifying this deficiency, a short but ambitious workshop was convened in Waikoloa, near Kona, Hawaii, from 26-28 April 2007. This workshop, sponsored by the Center for Research on the Changing Earth System (CRCES), NOAA, the U.S. Geological Survey, and the U.S. Army Corps of Engineers, brought together climatologists and sectoral specialists representing agriculture, water resources, economics, the insurance industry, and developing country interests

Sharing economies: Moving beyond binaries in a digital age

In periods of turbulence, the tendency to simplify messages and polarise debates is nothing new. In our hyper-mediated world of online technologies, where it seems that even national policy can be forged in the 140 characters of Twitter, it is more important than ever to retain spaces for in-depth debate of emergent phenomena that have disruptive and transformative potential. In this article, we follow this logic and argue that to fully understand the diverse range of practices and potential consequences of activities uncomfortably corralled under the ambiguous term 'the sharing economy' requires not a simplification of arguments, but an opening out of horizons to explore the many ways in which these phenomena have emerged and are evolving. It is argued that this will require attention to multiple terrains, from diverse intellectual traditions across many disciplines to the thus far largely reactive responses of government and regulation, and from the world of techno-innovation start-ups to the optics of media (including social media) reporting on what it means to 'share' in the 21st century. Building on this, we make the case for viewing 'the sharing economy' as a matrix of diverse economies with clear links to past practices. We propose that to build a grammar for understanding these diverse sharing economies requires further attention to: (1) The etymology of sharing and sharing economies; (2) The differentiated geographies to which sharing economies contribute; (3) What it means to labour, work and be employed in sharing economies; (4) The role of the state and others in governing, regulating and shaping the organisation and practice of sharing economies; and (5) the impacts of sharing economies. In conclusion, we suggest that while media interest may fade as their presence in everyday lives becomes less novel, understanding sharing economies remains an urgent activity if we are to ensure that the new ways of living and labouring, to which sharing economies are contributing, work to promote sustainable and inclusive development in this world that ultimately we all share

Climate Change and Market-Based Insurance Feedbacks

Climatic events have accounted for 91% of $1.05 trillion in insured costs for global catastrophic events from 1980 to 2016. Costs are driven by socio-economic development and increased frequency and severity of climatic disasters driven by climate change. Government policies to reduce systemic risk (e.g., cap-and-trade, carbon tax) have been a predominant approach for mitigation and adaptation. Alternatively, market-based incentives for climate change adaptation and mitigation already operate via the insurance industry to lessen impacts on society. Insurance feedbacks include changes in 1) premiums and insurance policies, 2) non-coverage, and 3) policy making and litigation. Alongside government policies, insurance feedbacks could be used to facilitate climate change adaptation and mitigation to a significant degree. Ultimately, a negotiated distribution of climate-related costs between the public and private insurance is needed

A Leptin-regulated Circuit Controls Glucose Mobilization During Noxious Stimuli

Adipocytes secrete the hormone leptin to signal the sufficiency of energy stores. Reductions in circulating leptin concentrations reflect a negative energy balance, which augments sympathetic nervous system (SNS) activation in response to metabolically demanding emergencies. This process ensures adequate glucose mobilization despite low energy stores. We report that leptin receptor–expressing neurons (LepRb neurons) in the periaqueductal gray (PAG), the largest population of LepRb neurons in the brain stem, mediate this process. Application of noxious stimuli, which often signal the need to mobilize glucose to support an appropriate response, activated PAG LepRb neurons, which project to and activate parabrachial nucleus (PBN) neurons that control SNS activation and glucose mobilization. Furthermore, activating PAG LepRb neurons increased SNS activity and blood glucose concentrations, while ablating LepRb in PAG neurons augmented glucose mobilization in response to noxious stimuli. Thus, decreased leptin action on PAG LepRb neurons augments the autonomic response to noxious stimuli, ensuring sufficient glucose mobilization during periods of acute demand in the face of diminished energy stores

A Ten-Fold Solvent Kinetic Isotope Effect for the Nonradiative Relaxation of the Aqueous Ferrate(VI) Ion

Hypervalent iron intermediates have been invoked in the catalytic cycles of many metalloproteins, and thus it is crucial to understand how the coupling between such species and their environment can impact their chemical and physical properties in such contexts. In this 2 work, we take advantage of the solvent kinetic isotope effect (SKIE) to gain insight into the nonradiative deactivation of electronic excited states of the aqueous ferrate(VI) ion. We observe an exceptionally large SKIE of 9.7 for the nanosecond-scale relaxation of the lowest energy triplet ligand field state to the ground state. Proton inventory studies demonstrate that a single solvent O-H bond is coupled to the ion during deactivation, likely due to the sparse vibrational structure of ferrate(VI). Such a mechanism is consistent with that reported for the deactivation of f-f excited states of aqueous trivalent lanthanides, which exhibit comparably large SKIE values. This phenomenon is ascribed entirely to dissipation of energy into a higher overtone of a solvent acceptor mode, as any impact on the apparent relaxation rate due to a change in solvent viscosity is negligible

Faint High Latitude Carbon Stars Discovered by the Sloan Digital Sky Survey: Methods and Initial Results

We report the discovery of 39 Faint High Latitude Carbon Stars (FHLCs) from Sloan Digital Sky Survey commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 < r* < 20.0, and show a diversity of temperatures as judged by both colors and NaD line strengths. At the completion of the Sloan Survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper motion measures for each object, indicating that the sample is a mixture of extremely distant (>100 kpc) halo giant stars, useful for constraining halo dynamics, plus members of the recently-recognized exotic class of very nearby dwarf carbon (dC) stars. Motions, and thus dC classification, are inferred for 40-50 percent of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. (Abstract abridged).Comment: Accepted for publication in The Astronomical Journal, Vol. 124, Sep. 2002, 40 pages, 7 figures, AASTeX v5.