Generalized Dissociating Gas Flow

A generalized approach to the one-dimensional flow of a dissociated gas is presented. The flow is characterized by the flow parameters F, G, H, and I, and the degree of dissociation, which are defined. The equation of state and the equations for the dynamic and thermodynamic properties of the gas are presented for the dissociating gas. Equations are presented which give the aerothermodynamic flow properties as a function of the degree of dissociation, the frozen flow Mach number MF, and the initial values of G, H, and I for any arbitrary given flight condition. These equations are solved for the limiting subsonic and hypersonic solutions for the flow variables as the frozen flow Mach number MF tends towards zero and infinity, respectively. Several aspects of the physical significance of these results are discussed from the point of view of atmospheric planetary entry of an aerospace vehicle. The generalized nondimensional flow function F is defined in terms of the flow parameters G, H, and I , and is also given as a function of MF, H, and a, in general. This functional relationship is displayed in graphical form which is useful for determining various aspects of the resulting flow, and providing further insight into the flow process under consideration. Specifically, several flow regimes are delineated

A System of Computer Programs to Calculate Aerodynamic Characteristics for Missiles, Reentry Vehicles, and Spacecraft at Angles of Attack

At the Fifth Space Congress, a method was [ presented for predicting the inviscid gas properties surrounding blunt nosed aerospace j vehicles in supersonic or hypersonic flight, at zero angle of attack {Reference l)o Two computer programs used in combination were utilized.) :At that time it was indicated (References 1 and 2) that this capability was to be extended, using j a new unique system of eleven different computer j programs, in order to provide for the calculation; of gaseous properties and aerodynamic characteristics for vehicles flying at angles of attack. At angles of attack, the problem of predicting the gas properties and aerodynamic characteristics is an order of magnitude more difficult due to the fact that the flow field is threedimensional. That is, the flow properties vary in all three directions: as a function of body axial station, location around the body (at a given station), and distance away from the body. ;The newer set of programs also provides the capability of handling vehicles with sharp as well as blunt noses, and includes the capability of predicting the viscous flow boundary layer properties on the vehicle surface. Most of the programs were originally developed under U.S. Air Force and Army Contracts by General Applied Science Laboratories. The programs were converted to operate on the Control Data Model CDC 6^-00 digital computer used at Martin Marietta I Corporation\u27s Orlando Division. Over the past year, many modifications have been made to the system of computer programs to increase the efficiency of utilization (by simplifying the j inputs required, etc.), reduce the computer run I time (cost of operation), and to increase its : capability (calculate aerodynamic characteristics etc.)

Geology and Structure of the Rough Creek Area, Western Kentucky

The Rough Creek area is a rectangular area about 113 mi east to west and 35 mi north to south encompassing about 3,900 mi2 in west-central and western Kentucky. The Ohio River delineates most of the western border with Illinois and locally also part of the northern border with Indiana. The northeast corner of the area is about 27 mi southwest of Louisville. The principal cities are Owensboro and Henderson. The Precambrian basement has been penetrated in only two wells in western Kentucky at depths somewhat greater than 14,000 ft. Basement is projected to underlie much of the area at a depth of more than 25,000 ft, and perhaps locally even more than 30,000 ft, in this, the deepest part of the Illinois Basin. Rocks of all geologic ages from Cambrian to Quaternary, except those of Mesozoic age, are present within the Rough Creek area; Upper Cretaceous strata occur as close as 20 mi south of the southeastern corner, however. All Paleozoic rocks older than Early Mississippian are restricted to the subsurface, so that the exposed rocks are dominantly of Mississippian (Meramecian and Chesterian) and Pennsylvanian ages. Strata of the Fort Payne Formation (Osagean) are present locally in the Rough Creek Fault Zone. Also, rocks of Early Permian age have been identified in a graben in the fault zone. Although no Pleistocene ice sheets penetrated south of the Ohio River in the Rough Creek area, the river valley was a major sluiceway for glacial debris from the Wisconsinan ice sheet, so the valley is filled with outwash, and loess blown from the valley blankets the area adjacent on the south. Remnants of Tertiary and Quarternary stream terraces are present in the Ohio and Green River Valleys, and thick lacustrine deposits covered by younger alluvium fill the larger stream valleys tributary to the Ohio River. The Rough Creek area is in the southern part of the Illinois Basin, and the principal structural features of the region that are present within or close to the study area, and at times influenced depositional patterns during the Paleozoic, include the Rough Creek–Shawneetown Fault System, the Moorman–Eagle Valley Syncline, the Pennyrile Fault System, and faults of the Illinois-Kentucky Fluorspar District. The Rough Creek–Shawneetown Fault System, which extends from western Kentucky into southeastern Illinois, where it is called the Shawneetown Fault Zone, is defined on its northern and western margins in Illinois by a southward-dipping, high-angle reverse fault with as much as 3,500 ft of reverse displacement. The frontal fault extends into Kentucky, but the degree of displacement is less than in Illinois; eastward along the structure, the frontal fault is broken into several long, arcuate segments by high-angle normal faults, and is displaced southward until it is no longer the frontal fault. In Kentucky, the Rough Creek zone is characterized by many steeply dipping fault blocks bounded by high-angle normal and reverse faults. The Moorman–Eagle Valley Syncline lies immediately south of the Rough Creek–Shawneetown Fault System, and that structure forms its steep northern and western limbs; the Kentucky part is the Moorman Syncline. The Pennyrile Fault System defines the gentle southern limb of the Moorman Syncline. In the deepest part of the composite syncline, which is close to its northern limb, structural relief on the Precambrian basement is more than 30,000 ft. The Moorman–Eagle Valley Syncline overlies the Rough Creek Graben in the basement. The Pennyrile Fault System, which lies mostly south of the Rough Creek area, is a broad feature composed of three branches of east- to northeast-trending, high-angle normal faults in an en echelon pattern that break the gently dipping strata into a series of fault blocks. Displacement on the faults generally increases to the west toward the junction of the fault system with faults of the Illinois-Kentucky Fluorspar District. The Pennyrile overlies the southern margin of the Rough Creek Graben, a structural feature in basement rocks

Architecture of the RNA polymerase II-Paf1C-TFIIS transcription elongation complex.

The conserved polymerase-associated factor 1 complex (Paf1C) plays multiple roles in chromatin transcription and genomic regulation. Paf1C comprises the five subunits Paf1, Leo1, Ctr9, Cdc73 and Rtf1, and binds to the RNA polymerase II (Pol II) transcription elongation complex (EC). Here we report the reconstitution of Paf1C from Saccharomyces cerevisiae, and a structural analysis of Paf1C bound to a Pol II EC containing the elongation factor TFIIS. Cryo-electron microscopy and crosslinking data reveal that Paf1C is highly mobile and extends over the outer Pol II surface from the Rpb2 to the Rpb3 subunit. The Paf1-Leo1 heterodimer and Cdc73 form opposite ends of Paf1C, whereas Ctr9 bridges between them. Consistent with the structural observations, the initiation factor TFIIF impairs Paf1C binding to Pol II, whereas the elongation factor TFIIS enhances it. We further show that Paf1C is globally required for normal mRNA transcription in yeast. These results provide a three-dimensional framework for further analysis of Paf1C function in transcription through chromatin

Charged pions from Ni on Ni collisions between 1 and 2 AGeV

Charged pions from Ni + Ni reactions at 1.05, 1.45 and 1.93 AGeV are measured with the FOPI detector. The mean $\pi^{\pm}$ multiplicities per mean number of participants increase with beam energy, in accordance with earlier studies of the Ar + KCl and La + La systems. The pion kinetic energy spectra have concave shape and are fitted by the superposition of two Boltzmann distributions with different temperatures. These apparent temperatures depend only weakly on bombarding energy. The pion angular distributions show a forward/backward enhancement at all energies, but not the $\Theta = 90^0$ enhancement which was observed in case of the Au + Au system. These features also determine the rapidity distributions which are therefore in disagreement with the hypothesis of one thermal source. The importance of the Coulomb interaction and of the pion rescattering by spectator matter in producing these phenomena is discussed.Comment: 22 pages, Latex using documentstyle[12pt,a4,epsfig], to appear in Z. Phys.

Influence of the in-medium pion dispersion relation in heavy ion collisions

We investigate the influence of medium corrections to the pion dispersion relation on the pion dynamics in intermediate energy heavy ion collisions. To do so a pion potential is extracted from the in-medium dispersion relation and used in QMD calculations and thus we take care of both, real and imaginary part of the pion optical potential. The potentials are determined from different sources, i.e. from the $\Delta$--hole model and from phenomenological approaches. Depending on the strength of the potential a reduction of the anti-correlation of pion and nucleon flow in non-central collisions is observed as well as an enhancement of the high energetic yield in transverse pion spectra. A comparison to experiments, in particular to $p_t$-spectra for the reaction Ca+Ca at 1 GeV/nucleon and the pion in-plane flow in Ne+Pb collisions at 800 MeV/nucleon, generally favours a weak potential.Comment: 25 pages, using REVTeX, 6 postscript figures; replaced by published versio

CDK12 globally stimulates RNA polymerase II transcription elongation and carboxyl-terminal domain phosphorylation

Cyclin-dependent kinase 12 (CDK12) phosphorylates the carboxyl-terminal domain (CTD) of RNA polymerase II (pol II) but its roles in transcription beyond the expression of DNA damage response genes remain unclear. Here, we have used TT-seq and mNET-seq to monitor the direct effects of rapid CDK12 inhibition on transcription activity and CTD phosphorylation in human cells. CDK12 inhibition causes a genome-wide defect in transcription elongation and a global reduction of CTD Ser2 and Ser5 phosphorylation. The elongation defect is explained by the loss of the elongation factors LEO1 and CDC73, part of PAF1 complex, and SPT6 from the newly-elongating pol II. Our results indicate that CDK12 is a general activator of pol II transcription elongation and indicate that it targets both Ser2 and Ser5 residues of the pol II CTD

A paper based graphene-nanocauliflower hybrid composite for point of care biosensing

Graphene paper has diverse applications in printed circuit board electronics, bioassays, 3D cell culture, and biosensing. Although development of nanometal-graphene hybrid composites is commonplace in the sensing literature, to date there are only a few examples of nanometal-decorated graphene paper for use in biosensing. In this manuscript, we demonstrate the synthesis and application of Pt nano cauliflower-functionalized graphene paper for use in electrochemical biosensing of small molecules (glucose, acetone, methanol) or detection of pathogenic bacteria (Escherichia coli O157:H7). Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy were used to show that graphene oxide deposited on nanocellulose crystals was partially reduced by both thermal and chemical treatment. Fractal platinum nanostructures were formed on the reduced graphene oxide paper, producing a conductive paper with an extremely high electroactive surface area, confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. To show the broad applicability of the material, the platinum surface was functionalized with three different biomaterials: 1) glucose oxidase (via chitosan encapsulation); 2) a DNA aptamer (via covalent linking), or 3) a chemosensory protein (via his linking). We demonstrate the application of this device for point of care biosensing. The detection limit for both glucose (0.08 ± 0.02 μM) and E. coli O157:H7 (1.3 ± 0.1 CFU mL-1) were competitive with, or superior to, previously reported devices in the biosensing literature. The response time (6 sec for glucose and 10 min for E. coli) were also similar to silicon biochip and commercial electrode sensors. The results demonstrate that the nanocellulose-graphene-nanoplatinum material is an excellent paper-based platform for development of electrochemical biosensors targeting small molecules or whole cells for use in point of care biosensing

Neutral Pions and Eta Mesons as Probes of the Hadronic Fireball in Nucleus-Nucleus Collisions around 1A GeV

Chemical and thermal freeze-out of the hadronic fireball formed in symmetric collisions of light, intermediate-mass, and heavy nuclei at beam energies between 0.8A GeV and 2.0A GeV are discussed in terms of an equilibrated, isospin-symmetric ideal hadron gas with grand-canonical baryon-number conservation. For each collision system the baryochemical potential mu_B and the chemical freeze-out temperature T_c are deduced from the inclusive neutral pion and eta yields which are augmented by interpolated data on deuteron production. With increasing beam energy mu_B drops from 800 MeV to 650 MeV, while T_c rises from 55 MeV to 90 MeV. For given beam energy mu_B grows with system size, whereas T_c remains constant. The centrality dependence of the freeze-out parameters is weak as exemplified by the system Au+Au at 0.8A GeV. For the highest beam energies the fraction of nucleons excited to resonance states reaches freeze-out values of nearly 15 %, suggesting resonance densities close to normal nuclear density at maximum compression. In contrast to the particle yields, which convey the status at chemical freeze-out, the shapes of the related transverse-mass spectra do reflect thermal freeze-out. The observed thermal freeze-out temperatures T_th are equal to or slightly lower than T_c, indicative of nearly simultaneous chemical and thermal freeze-out.Comment: 42 pages, 12 figure

Direct-write nanoscale printing of nanogranular tunnelling strain sensors for sub-micrometre cantilevers

The sensitivity and detection speed of cantilever-based mechanical sensors increases drastically through size reduction. The need for such increased performance for high-speed nanocharacterization and bio-sensing, drives their sub-micrometre miniaturization in a variety of research fields. However, existing detection methods of the cantilever motion do not scale down easily, prohibiting further increase in the sensitivity and detection speed. Here we report a nanomechanical sensor readout based on electron co-tunnelling through a nanogranular metal. The sensors can be deposited with lateral dimensions down to tens of nm, allowing the readout of nanoscale cantilevers without constraints on their size, geometry or material. By modifying the inter-granular tunnel-coupling strength, the sensors’ conductivity can be tuned by up to four orders of magnitude, to optimize their performance. We show that the nanoscale printed sensors are functional on 500 nm wide cantilevers and that their sensitivity is suited even for demanding applications such as atomic force microscopy