Replicator for characterization of cirrus and polar stratospheric cloud particles

A formvar replicator for installation in an aircraft pod has been designed, built, and flight tested on the NASA DC-8. The system incorporates a deicing capability (which can be pressure activated) to enable climb out through icing situations prior to deployment. The system can be operated at preselected speeds such that data can be recorded over a period of one to ten hours on 200 ft of 16mm film. A x2 speed control can be used during flight. Capability exists for detection of chemical constituents by appropriate doping of the formvar solution. An article entitled 'Measurements of ice particles in tropical cirrus anvils: importance in radiation balance' is attached as appendix A

Fi, Fie, Foe, Perot: Populist Giant or Grim Illusionist?

"Ross Perot. The billionaire. The presidential candidate. The man who made three references to the Tooth Fairy and the Easter Bunny in a recent debate with the Vice President. However one chooses to think of him, Ross Perot is an amazing individual. He simply did not exist as a national political figure two years ago. Yet his simple, down-to-earth approach to economics and government ("just plain talk"), his successful business background, and his stated desire to "do what's right for my country" landed him nearly 20 million votes in last year's presidential election —19 percent of the electorate — without the support of any major party (Fineman 34). A year later he remains the most potent political force in the United States outside the Beltway. This kind of popularity by a single, independent individual is unusual, to say the least. But contrary to Perot's own often used expression, it's just not that simple. Ross Perot is a skilled political operator, to be sure, but there are larger social, political, and economic forces sustaining his popularity. White House pollster Stan Greenberg is right when he says that Perot is largely a creation of the voters. The Texas billionaire has reached his current level of popularity because the public is dissatisfied with the nation's leadership."--from page

Teens and Mobile Phones.

Presents survey findings on trends in teenagers' use of and attitudes toward cell phone calling and text messaging, by age, gender, and plan type. Examines parents' views on and monitoring of cell phone-based communication as well as school restrictions

The National Program for Solar Energy

On October 26, 1974, the Solar Energy Research Development and Demonstration Act was signed into law authorizing a vigorous federal program of research development and demonstration to establish solar energy as a viable energy resource. Solar heating and cooling of buildings represents a midterm help in an attempt to be less dependent on oil and natural gas. Many other solar programs are underway in the development of solar energy

Ralph Ellison and the American Pursuit of Humanism

In the middle of a 1945 review of Bucklin Moon's Primer for White Folks, Ralph Ellison proclaims that the time is right in the United States for a "new American humanism." Through exhaustive research in Ralph Ellison's Papers at the Library of Congress, I contextualize Ellison's grand proclamation within post-World War II American debates over literary criticism, Modernism, sociological method, and finally United States political and cultural history. I see Ellison's "American humanism" as a revitalization of the Latin notion of litterae humaniores that draws heavily on Gilded Age American literature and philosophy. For Ellison, American artists and intellectuals of that period were grappling with the country's primary quandary after the Civil War: an inability to reconcile America's progressive vision of humanism with the legacy left by chattel slavery and anti-black racism. He saw writers like Mark Twain, Stephan Crane, Henry James, George Washington Cable and others attempting to represent a different version of the human in literature while confronting the various forces that the Civil War unleashed upon American life.As the Cold War and Civil Rights era reached their crescendo, Ellison's attachment to the Gilded Age ossified. By the late 60s, it took the romantic form of aesthetic and political conservatism. This process is part of his participation in what Francis Saunders called the "Cultural Cold War" against communism. For many - including Ellison - this participation made their aesthetic investment in modernism commensurate with their anti-communist ideology. In foregrounding the Cold War, I want to emphasize that the US State's intervention into the sphere of culture is a watershed moment in America's conceptualization of Western humanism. The CIA and the State Department's role in funding academic literary and cultural periodicals, art festivals, fellowships and other institutions of knowledge during the Cold War is a chapter of American intellectual life that shaped Ellison's world as well as those of his contemporaries. Just as importantly, this moment illuminates the key roles African-American intellectuals played in America's pursuit of humanism

Current Saturation in Field Emission from H-Passivated Si Nanowires

International audienceThis paper explores the field emission (FE) properties of highly crystalline Si nanowires (NWs) with controlled surface passivation. The NWs were batch-grown by the vapor_liquid_solid process using Au catalysts with no intentional doping. The FE current_voltage characteristics showed quasi-ideal current saturation that resembles those predicted by the basic theory for emission from semiconductors, even at room temperature. In the saturation region, the currents were extremely sensitive to temperature and also increased linearly with voltage drop along the nanowire. The latter permits the estimation of the doping concentration and the carrier lifetime, which is limited by surface recombination. The conductivity could be tuned over 2 orders of magnitude by in situ hydrogen passivation/desorption cycles. This work highlights the role of dangling bonds in surface leakage currents and demonstrates the use of hydrogen passivation for optimizing the FE characteristics of Si NWs

Field emission measure of the time response of individual semiconducting nanowires to laser excitation

International audienceA simple technique is explored to determine the temporal photo-response, s, of individual semiconducting SiC and Si nanowires (NWs), with a high time resolution. Laser-assisted field emission (LAFE) from the NWs is first shown to be highly sensitive to continuous laser illumination. Pulsed illumination is then combined with measurements of the total energy distributions to determine s which were rather large, 4-200 ls. The time response scaled roughly with the square of the NWs length and could be attributed to laser-induced heating. LAFE is thus a new tool for quantifying rapid thermo-optical effects in such nano-objects