9,951 research outputs found
Test instrumentation evaluates electrostatic hazards in fluid system
RJ-1 fuel surface potential is measured with a probe to determine the degree of hazard originating from static electricity buildup in the hydraulic fluid. The probe is mounted in contact with the fluid surface and connected to an electrostatic voltmeter
The PSF.p54nrb complex is a novel Mnk substrate that binds the mRNA for tumor necrosis factor alpha
To identify new potential substrates for the MAP kinase signal-integrating kinases (Mnks), we employed a proteomic approach. The Mnks are targeted to the translational machinery through their interaction with the cap-binding initiation factor complex. We tested whether proteins retained on cap resin were substrates for the Mnks in vitro, and identified one such protein as PSF (the PTB (polypyrimidine tract-binding protein)-associated splicing factor). Mnks phosphorylate PSF at two sites in vitro, and our data show that PSF is an Mnk substrate in vivo. We also demonstrate that PSF, together with its partner, p54nrb, binds RNAs that contain AU-rich elements (AREs), such as those for proinflammatory cytokines (e.g. tumor necrosis factor ? (TNF?)). Indeed, PSF associates specifically with the TNF? mRNA in living cells. PSF is phosphorylated at two sites by the Mnks. Our data show that Mnk-mediated phosphorylation increases the binding of PSF to the TNF? mRNA in living cells. These findings identify a novel Mnk substrate. They also suggest that the Mnk-catalyzed phosphorylation of PSF may regulate the fate of specific mRNAs by modulating their binding to PSF·p54nrb
Hybrid thermocouple development program
The design and development of a hybrid thermocouple, having a segmented SiGe-PbTe n-leg encapsulated within a hollow cylindrical p-SiGe leg, is described. Hybrid couple efficiency is calculated to be 10% to 15% better than that of a all-SiGe couple. A preliminary design of a planar RTG, employing hybrid couples and a water heat pipe radiator, is described as an example of a possible system application. Hybrid couples, fabricated initially, were characterized by higher than predicted resistance and, in some cases, bond separations. Couples made later in the program, using improved fabrication techniques, exhibited normal resistances, both as-fabricated and after 700 hours of testing. Two flat-plate sections of the reference design thermoelectric converter were fabricated and delivered to NASA Lewis for testing and evaluation
Human Capital Risk, Contract Enforcement, and the Macroeconomy
We develop a macroeconomic model with physical and human capital, human capital risk, and limited contract enforcement. We show analytically that young (high-return) households are the most exposed to human capital risk and are also the least insured. We document this risk-insurance pattern in data on life-insurance drawn from the Survey of Consumer Finance. A calibrated version of the model can quantitatively account for the life-cycle variation of insurance observed in the US data and implies welfare costs of under-insurance for young households that are equivalent to a 4 percent reduction in lifetime consumption. A policy reform that makes consumer bankruptcy more costly leads to a substantial increase in the volume of credit and insurance.
The Pacific Northwest story
The establishment of image analysis facilities for the operational utilization of LANDSAT data in Idaho, Oregon, and Washington is discussed. The hardware and software resources are described for each facility along with the range of services
Can\u27t Really Teach: CRT Bans Impose upon Teachers\u27 First Amendment Pedagogical Rights
The jurisprudence governing K-12 teachers’ speech protection has been a convoluted hodgepodge of caselaw since the 1960s when the Supreme Court established that teachers retain at least some First Amendment protection as public educators. Now, as new so-called Critical Race Theory bans prohibit an array of hot button topics in the classroom, K-12 teachers must either preemptively censor themselves or risk running afoul of these vague bans with indeterminate legal protection. This Note proposes an elucidation of K-12 teachers’ free speech rights via a two-part test to assess the reasonability of instructional speech. Rather than analogizing K-12 teacher speech to citizen speech, student speech, or public employee speech, as the leading Supreme Court cases direct lower courts to do, this test would account for the specific interests at play in K-12 education and consider the teacher’s pedagogical expertise.
As school board meetings host heated arguments and state legislatures ban books, the contours of K-12 public school teachers’ rights have never been more relevant. The Court continues to voice a need to maintain K-12 schools as the nurseries of democracy but does not articulate how teachers might do so in light of increasingly intrusive restrictions on speech. In higher education classrooms, professors retain academic freedom to cultivate a marketplace of ideas. In K-12 classrooms, teachers should preserve a corresponding freedom: the pedagogical freedom to teach permissible concepts in as myriad of ways. This Note argues that approaching K-12 teacher speech cases from the proposed two-step approach will clarify teachers’ First Amendment pedagogical freedom rights and thereby shield the kind of teacher instructional speech that is so crucial to U.S. democratic values
Design, Fabrication and Test of Composite Curved Frames for Helicopter Fuselage Structure
Aspects of curved beam effects and their importance in designing composite frame structures are discussed. The curved beam effect induces radial flange loadings which in turn causes flange curling. This curling increases the axial flange stresses and induces transverse bending. These effects are more important in composite structures due to their general inability to redistribute stresses by general yielding, such as in metal structures. A detailed finite element analysis was conducted and used in the design of composite curved frame specimens. Five specimens were statically tested and compared with predicted and test strains. The curved frame effects must be accurately accounted for to avoid premature fracture; finite element methods can accurately predict most of the stresses and no elastic relief from curved beam effects occurred in the composite frames tested. Finite element studies are presented for comparative curved beam effects on composite and metal frames
Altitude-Wind-Tunnel Investigation of the 19B-2, 19B-8, and 19XB-1 Jet-Propulsion Engines. II - Analysis of Turbine Performance of the 19B-8 Engine
Performance characteristics of the turbine in the 19B-8 jet propulsion engine were determined from an investigation of the complete engine in the Cleveland altitude wind tunnel. The investigation covered a range of simulated altitudes from 5000 to 30,000 feet and flight Mach numbers from 0.05 to 0.46 for various tail-cone positions over the entire operable range of engine speeds. The characteristics of the turbine are presented as functions of the total-pressure ratio across the turbine and the turbine speed and the gas flow corrected to NACA standard atmospheric conditions at sea level. The effect of changes in altitude, flight Mach number, and tail-cone position on turbine performance is discussed. The turbine efficiency with the tail cone in varied from a maximum of 80.5 percent to minimum of 75 percent over a range of engine speeds from 7500 to 17,500 rpm at a flight Mach number of 0.055. Turbine efficiency was unaffected by changes in altitude up to 15,000 feet but was a function of tail-cone position and flight Mach number. Decreasing the tail-pipe-nozzle outlet area 21 percent reduced the turbine efficiency between 2 and 4.5 percent. The turbine efficiency increased between 1.5 and 3 percent as the flight Mach number changed from 0.055 to 0.297
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