Aerocrane: A hybrid LTA aircraft for aerial crane applications

The Aerocrane, a hybrid aircraft, combines rotor lift with buoyant lift to offer VTOL load capability greatly in excess of helicopter technology while eliminating the airship problem of ballast transfer. In addition, the Aerocrane concept sharply reduces the mooring problem of airships and provides 360 deg vectorable thrust to supply a relatively large force component for control of gust loads. Designed for use in short range, ultra heavy lift missions, the Aerocrane operates in a performance envelope unsuitable for either helicopters or airships. Basic design considerations and potential problem areas of the concept are addressed

An implicit finite-difference solution to the viscous shock layer, including the effects of radiation and strong blowing

An implicit finite-difference scheme is developed for the fully coupled solution of the viscous, radiating stagnation-streamline equations, including strong blowing. Solutions are presented for both air injection and injection of carbon-phenolic ablation products into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative-transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized in the study. With minimum number of assumptions for the initially unknown parameters and profile distributions, convergent solutions to the full stagnation-line equations are rapidly obtained by a method of successive approximations. Damping of selected profiles is required to aid convergence of the solutions for massive blowing. It is shown that certain finite-difference approximations to the governing differential equations stabilize and improve the solutions. Detailed comparisons are made with the numerical results of previous investigations. Results of the present study indicate lower radiative heat fluxes at the wall for carbonphenolic ablation than previously predicted

Co-opting and resisting market based instruments for private land conservation

The increasing popularity of private land conservation (PLC) globally has quickly translated into an array of polices and programs aimed at achieving ecological benefits. The growth of PLC is entwined with the rise of neoliberal governance, with private land proving congruous with the promotion of market-based instruments (MBIs) and the reliance on private protected areas for conservation in lieu of government investment in public lands. Despite a growing literature on the implications of neoliberal environmental governance, there remains a need for specific insights into the way that individual landholders and ecologies can co-opt or resist the rationalities of MBIs in the practice of private land conservation. Through semi-structured interviews and property walks with 18 landholders, this research examines the implementation of a reverse-auction tender scheme called 'EcoTender' in Victoria, Australia. We uncovered four main tensions between the market logic of the program and conservation practice: 1) some landholders used the payment scheme to increase regulatory protections on their property through covenants/easements; 2) many landholders struggled to conceive of their stewardship practice as contractual labour; 3) landholders were producing novel ecosystems that challenged land management focused at the property parcel scale when EcoTender encouraged a return to historical benchmark ecologies, and; 4) many landholders wanted social collaboration when the program required competition for cost efficiency. Our insights show that PLC must create room for a diverse trajectory of conservation practice in dynamic socio-ecological contexts. This means careful reflection on the validity of assumptions underpinning MBIs, the trade-offs that come with applying market logic to conservation and the long-term implications of these instruments for policy and practice

The suppression of hidden order and onset of ferromagnetism in URu2Si2 via Re substitution

Substitution of Re for Ru in the heavy fermion compound URu2Si2 suppresses the hidden order transition and gives rise to ferromagnetism at higher concentrations. The hidden order transition of URu(2-x)Re(x)Si2, tracked via specific heat and electrical resistivity measurements, decreases in temperature and broadens, and is no longer observed for x>0.1. A critical scaling analysis of the bulk magnetization indicates that the ferromagnetic ordering temperature and ordered moment are suppressed continuously towards zero at a critical concentration of x = 0.15, accompanied by the additional suppression of the critical exponents gamma and (delta-1) towards zero. This unusual trend appears to reflect the underlying interplay between Kondo and ferromagnetic interactions, and perhaps the proximity of the hidden order phase.Comment: 8 pgs, 5 figs, ICM 2009; please refer to Phys. Rev. Lett. 103, 076404 (2009), arXiv:0908.1809 for details on magnetic scaling and phase diagram (reference added to this version

First order magnetic transition in CeFe2_2 alloys: Phase-coexistence and metastability

First order ferromagnetic (FM) to antiferromagnetic (AFM) phase transition in doped-CeFe$_2$ alloys is studied with micro-Hall probe technique. Clear visual evidence of magnetic phase-coexistence on micrometer scales and the evolution of this phase-coexistence as a function of temperature, magnetic field and time across the first order FM-AFM transition is presented. Such phase-coexistence and metastability arise as natural consequence of an intrinsic disorder-influenced first order transition. Generality of this phenomena involving other classes of materials is discussed.Comment: 11 pages of text and 3 figure

Stringent Phenomenological Investigation into Heterotic String Optical Unification

For the weakly coupled heterotic string (WCHS) there is a well-known factor of twenty conflict between the minimum string coupling unification scale, Lambda_H ~5x10^(17) GeV, and the projected MSSM unification scale, Lambda_U ~ 2.5x10^(16) GeV, assuming an intermediate scale desert (ISD). Renormalization effects of intermediate scale MSSM-charged exotics (ISME) (endemic to quasi-realistic string models) can resolve this issue, pushing the MSSM scale up to the string scale. However, for a generic string model, this implies that the projected Lambda_U unification under ISD is accidental. If the true unification scale is 5.0x10^(17) GeV, is it possible that illusionary unification at 2.5x10^(17) GeV in the ISD scenario is not accidental? If it is not, then under what conditions would the assumption of ISME in a WCHS model imply apparent unification at Lambda_U when ISD is falsely assumed? Geidt's "optical unification" suggests that Lambda_U is not accidental, by offering a mechanism whereby a generic MSSM scale Lambda_U < Lambda_H is guaranteed. A WCHS model was constructed that offers the possibility of optical unification, depending on the availability of anomaly-cancelling flat directions meeting certain requirements. This paper reports on the systematic investigation of the optical unification properties of the set of stringent flat directions of this model. Stringent flat directions can be guaranteed to be F-flat to all finite order (or to at least a given finite order consistent with electroweak scale supersymmetry breaking) and can be viewed as the likely roots of more general flat directions. Analysis of the phenomenology of stringent flat directions gives an indication of the remaining optical unification phenomenology that must be garnered by flat directions developed from them.Comment: standard latex, 18 pages of tex