27,874 research outputs found
A tool for measuring elevator cable tension
Simple tool for measuring relative cable tension is described, which weighs approximately two pounds, and can be produced at one-tenth cost of present tools
Viscosity dependence of the rates of diffusional processes
It is shown that the rates of diffusion-controlled processes may have a solvent vicosity independent part as well as a viscosity dependent part. Some relevant experiments involving intramolecular polypeptide movements are discussed, and implications for some experiments on diffusion in membranes are outlined
Protein folding, protein structure and the origin of life: Theoretical methods and solutions of dynamical problems
Theoretical methods and solutions of the dynamics of protein folding, protein aggregation, protein structure, and the origin of life are discussed. The elements of a dynamic model representing the initial stages of protein folding are presented. The calculation and experimental determination of the model parameters are discussed. The use of computer simulation for modeling protein folding is considered
“Advice and Consent” in Historical Perspective
In recent years, commentators have complained about what they regard as an increasingly dysfunctional confirmation process for judges and high-ranking executive officials, and the proper role for the Senate in the confirmation process has been much debated. This Article suggests that confirmations have been contentious throughout American history, and that the focus on ideological issues in today’s confirmation proceedings is not anomalous. Indeed, historically, both Republicans and Democrats have used the confirmation process to delay or oppose nominations when the President hails from a different political party, and, sometimes, even when the President comes from the same party but there are ideological objections to the nominee.
That the appointments process has, at times, been difficult and contentious should come as no great surprise. The Framers of the United States Constitution intentionally created a governmental structure that was more prone to obstructionism than other comparable systems. Relying on concepts like “separation of powers,” and “checks and balances,” the Framers sought to constrain the federal government in ways that would limit the possibilities for governmental abuse. The appointments power reflects this approach. Like many other constitutional powers, it is a shared power. Although the President has the power to nominate Article III judges, as well as ambassadors and “officers,” nominees can only be confirmed with the “advice and consent” of the Senate. By placing the power to appoint in two politically elected entities, the Constitution establishes a system whereby political influences will sometimes have a major impact on the confirmation process.
Although contentiousness can arise during any type of nomination, some Supreme Court nominations have been particularly bitter. Both the Senate and the American public have increasingly become aware that the courts make law and that the political and judicial attitudes of nominees matter. Under such circumstances, the Senate’s inquiry quite naturally goes beyond the simple question of whether a nominee is qualified or unqualified. However, the confirmation process is more difficult today, even for nonjudicial nominees, because of the bitter partisanship that has infected the U.S. political system
Analyses of earth radiation budget data from unrestricted broadband radiometers on the ESSA 7 satellite
Six months of data from the wide-field-of-view low resolution infrared radiometers on the Environmental Science Services Administration (ESSA) 7 satellite were analyzed. Earth emitted and earth reflected irradiances were computed at satellite altitude using data from a new in-flight calibration technique. Flux densitites and albedos were computed for the top of the earth's atmosphere. Monthly averages of these quantities over 100 latitude zones, each hemisphere, and the globe are presented for each month analyzed, and global distributions are presented for typical months. Emitted flux densities are generally lower and albedos higher than those of previous studies. This may be due, in part, to the fact that the ESSA 7 satellite was in a 3 p.m. Sun-synchronous orbit and some of the comparison data were obtained from satellites in 12 noon sun-synchronous orbits. The ESSA 7 detectors seem to smooth out spatial flux density variations more than scanning radiometers or wide-field-of-view fixed-plate detectors. Significant longitudinal and latitudinal variations of emitted flux density and albedo were identified in the tropics in a zone extending about + or - 25 deg in latitude
Simulation study of a geometric shape factor technique for estimating earth-emitted radiant flux densities from wide-field-of-view radiation measurements
Geometric shape factors were computed and applied to satellite simulated irradiance measurements to estimate Earth emitted flux densities for global and zonal scales and for areas smaller than the detector field of view (FOV). Wide field of view flat plate detectors were emphasized, but spherical detectors were also studied. The radiation field was modeled after data from the Nimbus 2 and 3 satellites. At a satellite altitude of 600 km, zonal estimates were in error 1.0 to 1.2 percent and global estimates were in error less than 0.2 percent. Estimates with unrestricted field of view (UFOV) detectors were about the same for Lambertian and limb darkening radiation models. The opposite was found for restricted field of view detectors. The UFOV detectors are found to be poor estimators of flux density from the total FOV and are shown to be much better as estimators of flux density from a circle centered at the FOV with an area significantly smaller than that for the total FOV
Coherent backscattering of ultrasound without a source
Coherent backscattering is due to constructive interferences of reciprocal
paths and leads to an enhancement of the intensity of a multiply scattered
field near its source. To observe this enhancement an array of receivers is
conventionally placed close to the source. Our approach here is different. In a
first experiment, we recover the coherent backscattering effect (CBE) within an
array of sources and a distant receiver using time correlation of diffuse
fields. The enhancement cone has an excellent spatial resolution. The dynamics
of the enhancement factor is studied in a second experiment using correlation
of thermal phonons at the same ultrasonic frequencies, without any active
source
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