Measurements of αs\alpha_s and parton distribution functions using HERA jet data

Use of HERA jet production cross sections can extend our knowledge of the gluon parton distribution function and yield accurate measurements of $\alpha_s(M_Z)$ in addition to illustrating the running of $\alpha_s$ with scale.Comment: Proceedings of the Ringberg Workshop on `New Trends in HERA Physics 2005

Determination of Charm Quark Mass and αs(MZ)\alpha_s(M_Z) from HERA data

Charm production data from HERA can be used to determine the charm quark mass and jet production data from HERA can be used to detrmine $\alpha_s(M_Z)$. recent results are summarised.Comment: 11 pages, 9 figures. Invited talk at the Workshop on the Fundamental Parameters of QCD, NTU, Singapore, March 201

Have we seen anything beyond (N)NLO DGLAP at HERA?

The evidence from HERA for parton saturation, and other low-$x$ effects beyond the conventional DGLAP formalism, is recalled and critically reviewed in the light of new data and analyses presented at the conference.Comment: 4 pages, 5 figures, Contribution to the discussion session at Intenrational Symposium on Multiparticle Dynamics, ISMD08, Hambur

Single-Cycle Impulse from Detonation Tubes with Nozzles

Experiments measuring the single-cycle impulse from detonation tubes with nozzles were conducted by hanging the tubes in a ballistic pendulum arrangement within a large tank. The detonation-tube nozzle and surrounding tank were initially filled with air between 1.4 and 100 kPa in pressure simulating high-altitude conditions. A stoichiometric ethylene–oxygen mixture at an initial pressure of 80 kPa filled the constant-diameter portion of the tube. Four diverging nozzles and six converging–diverging nozzles were tested. Two regimes of nozzle operation were identified, depending on the environmental pressure. Near sea-level conditions, unsteady gas-dynamic effects associated with the mass of air contained in the nozzle increase the impulse as much as 72% for the largest nozzle tested over the baseline case of a plain tube. Near vacuum conditions, the nozzles quasi-steadily expand the flow, increasing the impulse as much as 43% for the largest nozzle tested over the baseline case of a plain tube. Competition between the unsteady and quasi-steady-flow processes in the nozzle determine the measured impulse as the environmental pressure varies

Thermal and Catalytic Cracking of JP-10 for Pulse Detonation Engine Applications

Practical air-breathing pulse detonation engines (PDE) will be based on storable liquid hydrocarbon fuels such as JP-10 or Jet A. However, such fuels are not optimal for PDE operation due to the high energy input required for direct initiation of a detonation and the long deflagration-to-detonation transition times associated with low-energy initiators. These effects increase cycle time and reduce time-averaged thrust, resulting in a significant loss of performance. In an effort to utilize such conventional liquid fuels and still maintain the performance of the lighter and more sensitive hydrocarbon fuels, various fuel modification schemes such as thermal and catalytic cracking have been investigated. We have examined the decomposition of JP-10 through thermal and catalytic cracking mechanisms at elevated temperatures using a bench-top reactor system. The system has the capability to vaporize liquid fuel at precise flowrates while maintaining the flow path at elevated temperatures and pressures for extended periods of time. The catalytic cracking tests were completed utilizing common industrial zeolite catalysts installed in the reactor. A gas chromatograph with a capillary column and flame ionization detector, connected to the reactor output, is used to speciate the reaction products. The conversion rate and product compositions were determined as functions of the fuel metering rate, reactor temperature, system backpressure, and zeolite type. An additional study was carried out to evaluate the feasibility of using pre-mixed rich combustion to partially oxidize JP-10. A mixture of partially oxidized products was initially obtained by rich combustion in JP-10 and air mixtures for equivalence ratios between 1 and 5. Following the first burn, air was added to the products, creating an equivalent stoichiometric mixture. A second burn was then carried out. Pressure histories and schlieren video images were recorded for both burns. The results were analyzed by comparing the peak and final pressures to idealized thermodynamic predictions

Should organic farmers be rewarded for sequestering C in soil?

The question of whether farmers, and organic farmers in particular, should be rewarded for sequestering C in soils is controversial. A review of the literature on long term experiments comparing organic and conventional systems, demonstrates that soils under organic management tend to have higher soil organic carbon (SOC) contents than conventionally managed soils. But the logistics of designing a system that compensates individual farmers for this ecosystem service are challenging. Agreements would have to be reached on the baseline system used for calculation of relative gains in SOC, values for emissions of other GHGs from soils (e.g. methane and nitrous oxide), the direct and indirect CO2 emissions associated with energy use and crop production inputs in the C sequestering system, and emissions associated with sources of SOC imported onto the farm. Alternatively, the evidence for generally higher SOC under organic management could justify an additional payment, for example under the UK Government’s Organic Entry Level Scheme