A large advanced freight aircraft: F-81

Commercial air freight operations have grown in importance in recent years, due mainly to cost reductions caused by increasing aircraft and freight-terminal efficiencies. The bulk of this traffic is carried in the underfloor holds of wide-body passenger aircraft, but there is a significant sector of the market served by 'dedicated' freighters such as the 747F and DC8-63F. These aircraft are often equipped with standard containers and pallets which are loaded at factories or freight depots. The largest and most efficient container is the 8 ft x 8 ft x 20 ft size NASA felt the need to study the air-freight market and commissioned the extensive C.L.A.S.S. study (Ref.1). This report suggested that significant operating cost savings would be required, together with improved ground interfaces, to make more inroads into the surface transport market. It studied the economics of aircraft derived from current types, together with new designs. The former was more immediately attractive, but a market existed for new aircraft from the mid 1990's. The most attractive new type would be a long range aircraft with payload in the 75 to 165 ton range. The lower size aircraft was slightly more economic, but would pose grave airport frequency saturation problems and therefore a larger aircraft was preferable. Aircraft much above the 165 ton class however, would lead to development costs higher than the market could stand. An aircraft of about 165 tons payload seemed to be a good solution which could be made more attractive if it were designed to satisfy both civil and military requirements, thus spreading development costs. This philosophy was aimed at during the design of the Lockheed C-141 but too much emphasis was placed on military properties and no civil versions were sold. This should be avoided on a new design which should be capable of augmenting and partially replacing current fleets of 747F, DC10 CF and Lockheed C-5A aircraft … [cont.]

The measurement of household socio-economic position in tuberculosis prevalence surveys: a sensitivity analysis.

OBJECTIVE: To assess the robustness of socio-economic inequalities in tuberculosis (TB) prevalence surveys. DESIGN: Data were drawn from the TB prevalence survey conducted in Lusaka Province, Zambia, in 2005-2006. We compared TB socio-economic inequalities measured through an asset-based index (Index 0) using principal component analysis (PCA) with those observed using three alternative indices: Index 1 and Index 2 accounted respectively for the biases resulting from the inclusion of urban assets and food-related variables in Index 0. Index 3 was built using regression-based analysis instead of PCA to account for the effect of using a different assets weighting strategy. RESULTS: Household socio-economic position (SEP) was significantly associated with prevalent TB, regardless of the index used; however, the magnitude of inequalities did vary across indices. A strong association was found for Index 2, suggesting that the exclusion of food-related variables did not reduce the extent of association between SEP and prevalent TB. The weakest association was found for Index 1, indicating that the exclusion of urban assets did not lead to higher extent of TB inequalities. CONCLUSION: TB socio-economic inequalities seem to be robust to the choice of SEP indicator. The epidemiological meaning of the different extent of TB inequalities is unclear. Further studies are needed to confirm our conclusions

Searching Data: A Review of Observational Data Retrieval Practices in Selected Disciplines

A cross-disciplinary examination of the user behaviours involved in seeking and evaluating data is surprisingly absent from the research data discussion. This review explores the data retrieval literature to identify commonalities in how users search for and evaluate observational research data. Two analytical frameworks rooted in information retrieval and science technology studies are used to identify key similarities in practices as a first step toward developing a model describing data retrieval

FLAVIIR, An innovative university/industry research program for collaborative research and demonstration of UAV technologies

A major research programme into advanced technologies for Uninhabited Airborne Vehicles (UAVs) in June 2004. The £6.5M, five-year project represents a major investment in aerospace technology for BAE SYSTEMS and their partner, the Engineering and Physical Sciences Research Council (EPSRC). The focus of “FLAVIIR” is to develop technologies which support low cost (to acquire and operate) UAVs, together with the broader goal of improving the exploitation and hence impact of the research work completed through closer management of the research team. The project involves ten universities working together at two levels: inter-university collaboration within disciplines and interdisciplinary collaboration both within and across university boundaries. This aspect makes the project particularly challenging for Cranfield, as it is managing the complete project (with BAE Systems) and is to deliver the benefits of these joint activities. This work leads to the integration of the technologies into a sophisticated flying demonstrator UAV which is scheduled to fly in 2009. A particularly challenging requirement is that the vehicle should demonstrate an entire flight cycle, without the use of conventional flap-type control surfaces. The project now has more than 35 researchers working in subject areas ranging from novel aerodynamic techniques to develop control forces, novel flight control systems, to hybrid laser techniques to ‘write’ sensors and actuators directly onto carbon composite structures. The paper gives a description of the new technologies being developed, their integration into a number of demonstrations and the plans for their culmination in the Demon flying demonstrator vehicle, which will be based on the Eclipse Vehicle. The paper will also discuss the equally important issues of integrating, a multi-university/Industry research team

Progress towards a rapid method for conceptual aerodynamic design for transonic cruise

Results are presented from a study aimed at demonstrating the accuracy and efficiency of a lower order aerodynamic prediction method for transonic cruise flows around aircraft configurations, including conventional swept wing-body and also blended wing-body designs. The Viscous Full Potential (VFP) method, coupling the solution of the full potential equations with the integral boundary layer equations can yield data of almost equivalent accuracy as Navier-Stokes based CFD methods but at 0.5% - 2% of the physical time. In addition it is shown, using both the VFP approach and Delayed Detached Eddy Simulation (DDES) that the flow physics of the stall mechanism associated with blended wing-body configurations is far more complex than that experienced on more conventional swept-tapered wings. The mechanism appears to involve an initial tip stall but also involves highly 3D vortical flows inboard on the upper surface of the wing which significantly distorts the transonic shock wave

Advanced InSAR atmospheric correction: MERIS/MODIS combination and stacked water vapour models

A major source of error for repeat-pass Interferometric Synthetic Aperture Radar (InSAR) is the phase delay in radio signal propagation through the atmosphere (especially the part due to tropospheric water vapour). Based on experience with the Global Positioning System (GPS)/Moderate Resolution Imaging Spectroradiometer (MODIS) integrated model and the Medium Resolution Imaging Spectrometer (MERIS) correction model, two new advanced InSAR water vapour correction models are demonstrated using both MERIS and MODIS data: (1) the MERIS/MODIS combination correction model (MMCC); and (2) the MERIS/MODIS stacked correction model (MMSC). The applications of both the MMCC and MMSC models to ENVISAT Advanced Synthetic Aperture Radar (ASAR) data over the Southern California Integrated GPS Network (SCIGN) region showed a significant reduction in water vapour effects on ASAR interferograms, with the root mean square (RMS) differences between GPS- and InSAR-derived range changes in the line-of-sight (LOS) direction decreasing from ,10mm before correction to ,5mm after correction, which is similar to the GPS/MODIS integrated and MERIS correction models. It is expected that these two advanced water vapour correction models can expand the application of MERIS and MODIS data for InSAR atmospheric correction. A simple but effective approach has been developed to destripe Terra MODIS images contaminated by radiometric calibration errors. Another two limiting factors on the MMCC and MMSC models have also been investigated in this paper: (1) the impact of the time difference between MODIS and SAR data; and (2) the frequency of cloud-free conditions at the global scale

RAFT Aqueous Dispersion Polymerization of N -(2-(Methacryloyloxy)ethyl)pyrrolidone: A Convenient Low Viscosity Route to High Molecular Weight Water-Soluble Copolymers

RAFT solution polymerization of N-(2-(methacryoyloxy)ethyl)pyrrolidone (NMEP) in ethanol at 70 °C was conducted to produce a series of PNMEP homopolymers with mean degrees of polymerization (DP) varying from 31 to 467. Turbidimetry was used to assess their inverse temperature solubility behavior in dilute aqueous solution, with an LCST of approximately 55 °C being observed in the high molecular weight limit. Then a poly(glycerol monomethacylate) (PGMA) macro-CTA with a mean DP of 63 was chain-extended with NMEP using a RAFT aqueous dispersion polymerization formulation at 70 °C. The target PNMEP DP was systematically varied from 100 up to 6000 to generate a series of PGMA63–PNMEPx diblock copolymers. High conversions (≥92%) could be achieved when targeting up to x = 5000. GPC analysis confirmed high blocking efficiencies and a linear evolution in Mn with increasing PNMEP DP. A gradual increase in Mw/Mn was also observed when targeting higher DPs. However, this problem could be minimized (Mw/Mn < 1.50) by utilizing a higher purity grade of NMEP (98% vs 96%). This suggests that the broader molecular weight distributions observed at higher DPs are simply the result of a dimethacrylate impurity causing light branching, rather than an intrinsic side reaction such as chain transfer to polymer. Kinetic studies confirmed that the RAFT aqueous dispersion polymerization of NMEP was approximately four times faster than the RAFT solution polymerization of NMEP in ethanol when targeting the same DP in each case. This is perhaps surprising because both 1H NMR and SAXS studies indicate that the core-forming PNMEP chains remain relatively solvated at 70 °C in the latter formulation. Moreover, dissolution of the initial PGMA63–PNMEPx particles occurs on cooling from 70 to 20 °C as the PNMEP block passes through its LCST. Hence this RAFT aqueous dispersion polymerization formulation offers an efficient route to a high molecular weight water-soluble polymer in a rather convenient low-viscosity form. Finally, the relatively expensive PGMA macro-CTA was replaced with a poly(methacrylic acid) (PMAA) macro-CTA. High conversions were also achieved for PMAA85–PNMEPx diblock copolymers prepared via RAFT aqueous dispersion polymerization for x ≤ 4000. Again, better control was achieved when using the 98% purity NMEP monomer in such syntheses