Geometric properties of a prestressed segmented spherical shell

Design and construction of plastic model of prestressed segmented spherical shel

Detailed investigation of a vaporising fuel spray. Part 1: Experimental investigation of time averaged spray

A laser tomographic light scattering technique provides rapid and accurate high resolution measurements of droplet sizes, concentrations, and vaporization. Measurements using a computer interfaced thermocouple are presented and it is found that the potential exists for separating gas and liquid temperature measurements and diagnosing local spray density by in situ analysis of the response characteristics of the thermocouple. The thermocouple technique provides a convenient means for measuring mean gas velocity in both hot and cold two phase flows. The experimental spray is axisymmetric and has carefully controlled initial and boundary conditions. The flow is designed to give relatively insignificant transfer of momentum and mass from spray to air flow. The effects of (1) size-dependent droplet dispersion by the turbulence, (2) the initial spatial segregation of droplet sizes during atomization, and (3) the interaction between droplets and coherent large eddies are diagnosed

Fragility of the spin-glass-like collective state to a magnetic field in an interacting Fe-C nanoparticle system

The effect of applied magnetic fields on the collective nonequilibrium dynamics of a strongly interacting Fe-C nanoparticle system has been investigated. It is experimentally shown that the magnetic aging diminishes to finally disappear for fields of moderate strength. The field needed to remove the observable aging behavior increases with decreasing temperature. The same qualitative behavior is observed in an amorphous metallic spin glass (Fe_{0.15}Ni_{0.85})_{75}P_{16}B_6Al_3.Comment: 5 pages, 3 figure

Developement of real time diagnostics and feedback algorithms for JET in view of the next step

Real time control of many plasma parameters will be an essential aspect in the development of reliable high performance operation of Next Step Tokamaks. The main prerequisites for any feedback scheme are the precise real-time determination of the quantities to be controlled, requiring top quality and highly reliable diagnostics, and the availability of robust control algorithms. A new set of real time diagnostics was recently implemented on JET to prove the feasibility of determining, with high accuracy and time resolution, the most important plasma quantities. With regard to feedback algorithms, new model–based controllers were developed to allow a more robust control of several plasma parameters. Both diagnostics and algorithms were successfully used in several experiments, ranging from H-mode plasmas to configuration with ITBs. Since elaboration of computationally heavy measurements is often required, significant attention was devoted to non-algorithmic methods like Digital or Cellular Neural/Nonlinear Networks. The real time hardware and software adopted architectures are also described with particular attention to their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Flavin mononucleotide: the coenzyme of reduced diphosphopyridine nucleotide dehydrogenase

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Controlling ferromagnetic ground states and solitons in thin films and nanowires built from iron phthalocyanine chains

Iron phthalocyanine (FePc) is a molecular semiconductor whose building blocks are one-dimensional ferromagnetic chains. We show that its optical and magnetic properties are controlled by the growth strategy, obtaining extremely high coercivities of over 1 T and modulating the exchange constant between 15 and 29 K through tuning the crystal phase by switching from thin films with controlled orientations, to ultralong nanowires. Magnetisation measurements are analysed using concepts and formulas with broad applicability to all one-dimensional ferromagnetic chains. They show that FePc is best described by a Heisenberg model with moments preferentially lying in the molecular planes. The chain Hamiltonian is very similar to that for the classic inorganic magnet CsNiF3, but with ferromagnetic rather than antiferromagnetic interchain interactions. The data at large magnetic fields are well-described by the soliton picture, where the dominant degrees of freedom are moving one-dimensional magnetic domain walls and at low temperatures and fields by the “super-Curie-Weiss” law characteristic of nearly one-dimensional xy and Heisenberg ferromagnets. The ability to control the molecular orientation and ferromagnetism of FePc systems, and produce them on flexible substrates, together with excellent transistor characteristics reported previously for phthalocyanine analogues, makes them potentially useful for magneto-optical and spintronic devices

Winter Grazing in a Grass-Fed System: Effect of Stocking Density and Sequential Use of Autumn-Stockpiled Grassland on Performance of Yearling Steers

Winter grazing can help reduce the need for purchased feeds in livestock production systems, when finishing cattle on pasture. Our objective was to evaluate the influence of stocking density and grazing stockpiled forage on performance of yearling steers during winter. Three grasslands were winter grazed for two years: I, naturalized pastureland, and II and III, sown and managed for hay production during the growing season but grazed in winter. Two stocking densities were used: low 7.41 and high 12.35 steers ha−1. Herbage mass was estimated before and after each grazing event, and disappearance (consumption, weathering, and trampling) was the difference between both. Forage mass and residual differed by stocking density (SD), year (YR), and grazing interval (GI), and disappearance differed by YR and GI. Grass and dead constituents of botanical composition differed by YR and GI. No differences were found for legumes and forbs. CP differed by YR and GI, and NDF and ADF differed only by YR. Steer average daily gain was 0.15 kg d−1 in 2011 and 0.68 kg d−1 in 2012 and varied by YR and GI. Acceptable gains in 2012 may be a product of environmental conditions that influenced herbage mass and nutritive value during stockpile and animal behavior during winter

Female cricket pace bowling: kinematic and anthropometric relationships with ball release speed

Background: Despite an increase in the professionalism and participation of female cricket, the coaching of female pace bowling is still reliant on male-derived knowledge. Objectives: To investigate the association between key male-derived kinematic and anthropometric parameters and ball release speed (BRS) in female pace bowlers. Methods: Eleven female pace bowlers participated in this study. BRS, and four anthropometric and five kinematic parameters were determined. Stepwise linear regression and Pearson Product Moment correlations were used to identify anthropometric and kinematic parameters linked to BRS. Results: The best predictor of BRS explaining 89% of the observed variance was the bowling shoulder angle at ball release. The best anthropometric predictor of BRS was height explaining 53% of the observed variance. Other parameters correlated with BRS included: run-up speed (r = 0.75, p = 0.013) and arm length (r = 0.61, p = 0.046). When height was controlled for, the front knee angle at front foot contact was also correlated to BRS (r = 0.68, p = 0.044). No relationship was found between trunk flexion and BRS. Conclusion: Faster BRS were characterised by faster run-up speeds, straighter front knees, and delayed arm circumduction similar to male pace bowlers. The lack of relationship between trunk flexion and BRS may highlight female pace bowlers adopting a bowling technique where BRS is contributed to by trunk rotation as well as trunk flexion. This knowledge is likely to be useful in the talent identification and coaching of female pace bowlers

Cost Analysis In A Multi-Mission Operations Environment

Spacecraft control centers have evolved from dedicated, single-mission or single missiontype support to multi-mission, service-oriented support for operating a variety of mission types. At the same time, available money for projects is shrinking and competition for new missions is increasing. These factors drive the need for an accurate and flexible model to support estimating service costs for new or extended missions; the cost model in turn drives the need for an accurate and efficient approach to service cost analysis. The National Aeronautics and Space Administration (NASA) Huntsville Operations Support Center (HOSC) at Marshall Space Flight Center (MSFC) provides operations services to a variety of customers around the world. HOSC customers range from launch vehicle test flights; to International Space Station (ISS) payloads; to small, short duration missions; and has included long duration flagship missions. The HOSC recently completed a detailed analysis of service costs as part of the development of a complete service cost model. The cost analysis process required the team to address a number of issues. One of the primary issues involves the difficulty of reverse engineering individual mission costs in a highly efficient multimission environment, along with a related issue of the value of detailed metrics or data to the cost model versus the cost of obtaining accurate data. Another concern is the difficulty of balancing costs between missions of different types and size and extrapolating costs to different mission types. The cost analysis also had to address issues relating to providing shared, cloud-like services in a government environment, and then assigning an uncertainty or risk factor to cost estimates that are based on current technology, but will be executed using future technology. Finally the cost analysis needed to consider how to validate the resulting cost models taking into account the non-homogeneous nature of the available cost data and the decreasing flight rate. This paper presents the issues encountered during the HOSC cost analysis process, and the associated lessons learned. These lessons can be used when planning for a new multi-mission operations center or in the transformation from a dedicated control center to multi-center operations, as an aid in defining processes that support future cost analysis and estimation. The lessons can also be used by mature serviceoriented, multi-mission control centers to streamline or refine their cost analysis process