18,450 research outputs found
Computer program simulates design, test, and analysis phases of sensitivity experiments
Modular program with a small main program and several specialized subroutines provides a general purpose computer program to simulate the design, test and analysis phases of sensitivity experiments. This program allows a wide range of design-response function combinations and the addition, deletion, or modification of subroutines
The Aerodynamic Forces and Moments on a Spinning Model of the F4B-2 Airplane as Measured by the Spinning Balance
The aerodynamic forces and moments on a 1/12-scale model of the F4B-2 airplane were measured with the spinning balance in nine spinning attitudes with three sets of tail surfaces, namely, F4B-2 surfaces; F4B-4 fin and rudder with rectangular stabilizer; and with all tail surfaces removed. In one of these attitudes measurements were made to determine the effect upon the forces and moments of independent and of simultaneous displacement of the rudder and elevator for two of the sets of tail surfaces. Additional measurements were made for a comparison of model and full-scale data for six attitudes that were determined from flight tests with various control settings. The characteristics were found to vary in the usual manner with angle of attack and sideslip. The F4B-2 surfaces were quite ineffective as a source of yawing moments. The F4B-4 fin and F4B-2 stabilizer gave a greater damping yawing moment when controls were against the spin than did the F4B-2 surfaces but otherwise there was little difference. Substitution of a rectangular stabilizer for the F4B-2 stabilizer made no appreciable difference in the coefficient. Further comparisons with other airplane types are necessary before final conclusions can be drawn as to the relations between model and full-scale spin measurements
Investigations of the lower and middle atmosphere at the Arecibo Observatory and a description of the new VHF radar project
The atmospheric science research at the Arecibo Observatory is performed by means of (active) radar methods and (passive) optical methods. The active methods utilize the 430 NHz radar, the S-band radar on 2380 MHz, and a recently constructed Very High Frequency (VHF) radar. The passive methods include measurements of the mesopause temperature by observing the rotational emissions from OH-bands. The VHF radar design is discussed
Fabrication and Electrical Characterization of Fully CMOS Si Single Electron Devices
We present electrical data of silicon single electron devices fabricated with
CMOS techniques and protocols. The easily tuned devices show clean Coulomb
diamonds at T = 30 mK and charge offset drift of 0.01 e over eight days. In
addition, the devices exhibit robust transistor characteristics including
uniformity within about 0.5 V in the threshold voltage, gate resistances
greater than 10 G{\Omega}, and immunity to dielectric breakdown in electric
fields as high as 4 MV/cm. These results highlight the benefits in device
performance of a fully CMOS process for single electron device fabrication.Comment: 7 pages, 7 figure
Method to determine the optimal parameters of the Arecibo 46.8-MHz antenna system
The spherical reflector at the Arecibo Observatory (AO) offers great advantages for the design of simple and inexpensive high performance steerable antennas at VHF. Light and small feeds have the added benefit that they can be quickly installed in the Arecibo platform. It is important to evaluate the performance of any given feed including the effects of the spherical reflector. The optimization is emphasized of two parameters, namely, the distance below the focal point of the reflector and the beam width of a point feed. For the design of the feed at 46.8 MHz at the AO there were other requirements independent of MST (mesosphere stratosphere troposphere) work. The design of the primary array is discussed along with its performance with the AO spherical reflector
Statistical analysis for thermometric sensors test program final report
Statistical models for regression analysis of thermometric sensor
Dynamics of Co-translational Membrane Protein Integration and Translocation via the Sec Translocon
An important aspect of cellular function is the correct targeting and delivery of newly synthesized proteins. Central to this task is the machinery of the Sec translocon, a transmembrane channel that is involved in both the translocation of nascent proteins across cell membranes and the integration of proteins into the membrane. Considerable experimental and computational effort has focused on the Sec translocon and its role in nascent protein biosynthesis, including the correct folding and expression of integral membrane proteins. However, the use of molecular simulation methods to explore Sec-facilitated protein biosynthesis is hindered by the large system sizes and long (i.e., minute) timescales involved. In this work, we describe the development and application of a coarse-grained simulation approach that addresses these challenges and allows for direct comparison with both in vivo and in vitro experiments. The method reproduces a wide range of experimental observations, providing new insights into the underlying molecular mechanisms, predictions for new experiments, and a strategy for the rational enhancement of membrane protein expression levels
Green chemistry and green engineering in China: drivers, policies and barriers to innovation
With the world’s largest population and consistently rapid rates of economic growth, China faces a choice of whether it will move towards a more sustainable development trajectory. This paper identifies the different factors driving innovation in the fields of green chemistry and green engineering in China, which we find to be largely driven by energy efficiency policy, increasingly strict enforcement of pollution regulations, and national attention to cleaner production concepts, such as “circular economy.” We also identify seven key barriers to the development and implementation of green chemistry and engineering in China. They are (1) competition between economic growth and environmental agendas, (2) regulatory and bureaucratic barriers, (3) availability of research funding, (4) technical barriers, (5)workforce training, (6) industrial engineering capacity, and (7) economic and financial barriers. Our analysis reveals that the most crucial barriers to green chemistry and engineering nnovations in China appear to be those that arise from competing priorities of economic growth and environmental protection as well as the technical challenges that arise from possessing a smaller base of experienced human capital. We find that there is a great deal of potential for both the development of the underlying science, as well as its implementation throughout the chemical enterprise, especially if investment occurs before problems of technological lock-in and sunk costs emerge
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