475 research outputs found

    Unemployment in Sunderland

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    The close relationship between the percentage unemployment in Sunderland and in Great Britain is demonstrated and some explanations offered. The specific performance of the main heavy industries in Sunderland, shipbuilding and heavy engineering, is unlikely to be the main cause of the problem. The explanations offered are contrary to the views of the International Labour Office (1962) and A.J. Brown (1972) Eight identifiable reasons are offered, with a possible ninth. Following Cameron (1971) one reason is the relative technical inefficiency of manufacturing plants, a cause which cannot be removed without more specific regional policy than exists at present. The very limited effect ofpast policy on Sunderland is demonstrated. The strong link between low educational achievement and high unemployment is shown and the need for a different approach to education in Sunderland is emphasised

    Exploratory Measurement of Recession Rates of Low Temperature Ablators Subjected to Mach 6 Flow

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    The high speed/high-temperature effect of heat shield ablation was simulated in the low-enthalpy AFRL Mach 6 Ludwieg Tube using solid dry ice as a low-temperature sublimator. The experiments utilized both 21 half-angle cones and bi-conic models with a 7 ° half-angle leading edge followed by a 26° half-angle base contained within a cryogenic-cooled stainless steel holder. A method of fabricating dry ice test articles was developed using commercially procured dry ice and custom-made aluminum molds. Tests were performed at Mach 6.1 with a stagnation temperature of 490 K and stagnation pressures ranging from 40 - 500 psi. Unit Reynolds number ranged from 2.6 x 106 to 23 x 106 m−1 . High-speed Schlieren photography with a frame rate of 20 kHz was used for visualization and data analysis. The observed ablation rates compared favorably to previous research and were analyzed using the Fay-Riddell stagnation point heating correlation. This exploratory effort demonstrated the potential for other uses of dry ice test models in the facility, including for store separation experiments and localized particle-based flow visualization

    Una traduzione dalla voce al gesto

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    A Statistical investigation of the invariant latitude dependence of unstable magnetospheric ion populations in relation to high m ULF wave generation

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    International audienceA statistical study is presented of the unstable proton populations, which contain the free energy required to drive small-scale poloidal mode ULF waves in the magnetosphere, observed at invariant latitudes of 60° to 80°. The data are all in the form of Ion Distribution Functions (IDFs) amassed over ~6 years using the CAMMICE (MICS) instrument on the Polar spacecraft, and cover proton energies of 1 keV to 328 keV. The free energy contained in the unstable, positive gradient regions of the IDFs is available to drive resonant wave growth. The results show that positive gradient regions in IDFs on magnetic field lines corresponding to the lower invariant latitudes in the range under study occur predominantly in the afternoon sector at proton energies of 5 keV to 20 keV. In the morning and dawn sectors positive gradient regions are seen with a typical proton energy range of 5 keV to 45 keV. While the proton energy peaks in the afternoon sector at around ~7 keV the morning sector has two peaks occurring at ~10 keV and ~20?30 keV. The technique of Baddeley et al. (2004), employed to quantify the free energy in each IDF, found that as invariant latitude increased the free energy contained in the positive gradient regions fell. Positive gradient regions in the afternoon sector decrease in number with invariant latitude at a faster rate than those in the morning sector. The majority of positive gradient regions had free energy values of >1010 J with many at the lowest invariant latitudes having free energies of in excess of 1011 J. Positive gradient regions at proton energies of >100 keV are rarely observed, and have free energies of typically <1

    A comparison of azimuthal and axial oscillation microfiltration using surface and matrix types of microfilters with a cake-slurry shear plane exhibiting non-Newtonian behaviour

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    The mode of application of oscillation, axial or azimuthal, did not influence filtration performance, when filtering a calcite mineral with a d32 value of 2.7 µm. The equilibrium flux and deposit thickness correlated with shear stress, regardless of: filter type (metal slotted surface filter or homogeneous sintered filter); and mode of oscillation. Shear stress values up to 240 Pa were used and the particle compact believed to be at, or near, the deposited solids showed non-Newtonian flow behaviour described by the Herschel-Bulkley equation. The shear was computed using Comsol® to model the shear at, and near, the oscillating surface. The peak shear (maximum value) was used in the correlation for flux, which appeared to fit the data well and provide a realistic prediction for sustainable flux using a force balance model. The existence of a yield stress in the compact appeared to limit the internal fouling of the matrix (homogeneous) type of filter, which had a membrane thickness of 8 mm, but did not demonstrate significant internal fouling over time, nor between filtrations. Thus, the results were similar to those obtained for the surface filters, and the resistance to filtration was dominated by the deposit formed

    STATIC BENDING STRENGTH AND STIFFNESS IN JUVENILE AND ADULT WOOD OF FAST-GROWING Pinus taeda L.

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    Due to the high growth rates of the forests planted in Brazil and the variations of the mechanical properties within a tree, this study aimed to evaluate the strength (MOR) and stiffness (MOE) in static bending according to the juvenile and adult wood, and the grown-rings inclination at the transversal area of clean specimens of Pinus taeda. Subsequently, the woods were classified in its structural gradings. Pinus taeda logs with 30 years old had the growth rings delimited at every six years on the transversal area.  The juvenile wood was represented by the zone of 0 to 6 years of growth (marked with red), and 6.1-12 years (blue). The zone of 12.1-18 (orange) was considered as transition wood and from 18.1-24 (green) and 24.1-30 years (yellow), adult wood. After the sawing, 25 boards were selected to the sawing of the specimens (n = 104) for the static bending test. Growth-ring inclination was measured as a function of the direction of the load applied at the bending test.  Statistical tests were performed in a factorial scheme with the MOR and MOE to static bending. Factors were independent (mechanical properties and growth-rings inclination). The 0-6-year-old wood was not indicated for structural use. Woods between 12-30 years old showed a minimum compatible result to be classified for structural use. The inclination did not influence at the modulus of elasticity and strength at bending

    Structural basis for a six nucleotide genetic alphabet

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    Expanded genetic systems are most likely to work with natural enzymes if the added nucleotides pair with geometries that are similar to those displayed by standard duplex DNA. Here, we present crystal structures of 16-mer duplexes showing this to be the case with two nonstandard nucleobases (Z, 6-amino-5-nitro-2(1H)-pyridone and P, 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)one) that were designed to form a Z:P pair with a standard “edge on” Watson–Crick geometry, but joined by rearranged hydrogen bond donor and acceptor groups. One duplex, with four Z:P pairs, was crystallized with a reverse transcriptase host and adopts primarily a B-form. Another contained six consecutive Z:P pairs; it crystallized without a host in an A-form. In both structures, Z:P pairs fit canonical nucleobase hydrogen-bonding parameters and known DNA helical forms. Unique features include stacking of the nitro group on Z with the adjacent nucleobase ring in the A-form duplex. In both B- and A-duplexes, major groove widths for the Z:P pairs are approximately 1 Å wider than those of comparable G:C pairs, perhaps to accommodate the large nitro group on Z. Otherwise, ZP-rich DNA had many of the same properties as CG-rich DNA, a conclusion supported by circular dichroism studies in solution. The ability of standard duplexes to accommodate multiple and consecutive Z:P pairs is consistent with the ability of natural polymerases to biosynthesize those pairs. This, in turn, implies that the GACTZP synthetic genetic system can explore the entire expanded sequence space that additional nucleotides create, a major step forward in this area of synthetic biology

    Silver(I) complexes of 9-anthracenecarboxylic acid and imidazoles: synthesis, structure and antimicrobial activity

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    [Ag2(9-aca)2] (1) (9-acaH = 9-anthracenecarboxylic acid) reacts with a series of imidazoles to give [Ag(imidH)2.3(CH3CN)0.7](9-aca) (3), [Ag6(imidH)4(9-aca)6(MeOH)2] (4), {[Ag(1-Me-imid)2]2[Ag4(9- aca)6]} (5), {[Ag(1-Bu-imid)2]2[Ag4(9-aca)6]} (6) and [Ag(apim)](9-aca)·H2O (7) (imidH = imidazole; 1-Me-imid = 1-methylimidazole; 1-Bu-imid = 1-butylimidazole; apim = 1-(3-aminopropyl)imidazole). The mononuclear complex 3, hexanuclear 4–6, and polymeric 7, were all characterised using X-ray crystallography. While many of the complexes possess excellent in vitro antifungal and antibacterial activities they are, unanimously, more effective against fungal cells. The insect, Galleria mellonella, can survive high doses of the Ag(I) complexes administered in vivo, and a number of the complexes offer significant protection to larvae infected with a lethal dose of pathogenic Candida albicans cells
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