Studies of noise transmission in advanced composite material structures

Noise characteristics of advanced composite material fuselages were discussed from the standpoints of applicable research programs and noise transmission theory. Experimental verification of the theory was also included

Effects of anisotropy in spin molecular-orbital coupling on effective spin models of trinuclear organometallic complexes

We consider layered decorated honeycomb lattices at two-thirds filling, as realized in some trinuclear organometallic complexes. Localized $S=1$ moments with a single-spin anisotropy emerge from the interplay of Coulomb repulsion and spin molecular-orbit coupling (SMOC). Magnetic anisotropies with bond dependent exchange couplings occur in the honeycomb layers when the direct intracluster exchange and the spin molecular-orbital coupling are both present. We find that the effective spin exchange model within the layers is an XXZ + 120$^\circ$ honeycomb quantum compass model. The intrinsic non-spherical symmetry of the multinuclear complexes leads to very different transverse and longitudinal spin molecular-orbital couplings, which greatly enhances the single-spin and exchange coupling anisotropies. The interlayer coupling is described by a XXZ model with anisotropic biquadratic terms. As the correlation strength increases the systems becomes increasingly one-dimensional. Thus, if the ratio of SMOC to the interlayer hopping is small this stabilizes the Haldane phase. However, as the ratio increases there is a quantum phase transition to the topologically trivial `$D$-phase'. We also predict a quantum phase transition from a Haldane phase to a magnetically ordered phase at sufficiently strong external magnetic fields.Comment: 22 pages, 11 figures. Final version of paper to be published in PRB. Important corrections to appendix

Heisenberg and Dzyaloshinskii-Moriya interactions controlled by molecular packing in tri-nuclear organometallic clusters

Motivated by recent synthetic and theoretical progress we consider magnetism in crystals of multi-nuclear organometallic complexes. We calculate the Heisenberg symmetric exchange and the Dzyaloshinskii-Moriya antisymmetric exchange. We show how, in the absence of spin-orbit coupling, the interplay of electronic correlations and quantum interference leads to a quasi-one dimensional effective spin model in a typical tri-nuclear complex, Mo$_3$S$_7$(dmit)$_3$, despite its underlying three dimensional band structure. We show that both intra- and inter-molecular spin-orbit coupling can cause an effective Dzyaloshinskii-Moriya interaction. Furthermore, we show that, even for an isolated pair of molecules the relative orientation of the molecules controls the nature of the Dzyaloshinskii-Moriya coupling. We show that interference effects also play a crucial role in determining the Dzyaloshinskii-Moriya interaction. Thus, we argue, that multi-nuclear organometallic complexes represent an ideal platform to investigate the effects of Dzyaloshinskii-Moriya interactions on quantum magnets.Comment: This update incorporates the corrections described in a recently submitted erratum. Changes are confined to sections IV.A and B. The conclusions of the paper are unchanged. 12 + 4 pages, 9 figure

Spin-orbit coupling in {Mo3_3S7_7(dmit)3_3}

Spin-orbit coupling in crystals is known to lead to unusual direction dependent exchange interactions, however understanding of the consequeces of such effects in molecular crystals is incomplete. Here we perform four component relativistic density functional theory computations on the multi-nuclear molecular crystal {Mo$_3$S$_7$(dmit)$_3$} and show that both intra- and inter-molecular spin-orbit coupling are significant. We determine a long-range relativistic single electron Hamiltonian from first principles by constructing Wannier spin-orbitals. We analyse the various contributions through the lens of group theory. Intermolecular spin-orbit couplings like those found here are known to lead to quantum spin-Hall and topological insulator phases on the 2D lattice formed by the tight-binding model predicted for a single layer of {Mo$_3$S$_7$(dmit)$_3$}

‘Overwhelmed and powerless’: Staff perspectives on mother-infant separations in English prisons

Imprisoned mothers are at increased risk for poor psychological health and psychological distress when separated from their children, so staff need to be highly skilled to support the women. However, there is a paucity of research focusing on staff experiences around sensitive issues such as mother-child separation. This study aimed to understand the challenges facing staff and how these might be addressed. This qualitative interview study explored the views and experiences of 24 prison-based staff in England working with female prisoners separated from their infants. Staff emphasised the challenges of working with separated mothers, specifically the emotional impact of this work, and the impact of the wider criminal justice system on their sense of agency. A focus on the experience of separation highlights the broader problem of incarcerating women in general. Reducing the number of mother-child separations would mitigate the impact on both women and staff

Alsophis antiguae

Number of Pages: 3Integrative BiologyGeological Science

Determination of ASPS performance for large payloads in the shuttle orbiter disturbance environment

A high fidelity simulation of the annular suspension and pointing system (ASPS), its payload, and the shuttle orbiter was used to define the worst case orientations of the ASPS and its payload for the various vehicle disturbances, and to determine the performance capability of the ASPS under these conditions. The most demanding and largest proposed payload, the Solar Optical Telescope was selected for study. It was found that, in all cases, the ASPS more than satisfied the payload's requirements. It is concluded that, to satisfy facility class payload requirements, the ASPS or a shuttle orbiter free-drift mode (control system off) should be utilized

Mother-infant separations in prison. A systematic attachment-focused policy review

Mothers in prison separated from their young children are an overlooked group. Attachment theory could provide a useful model to underpin interventions and better support women affected by separation from their infants. Current policy draws on a limited body of evidence and research has developed considerably since its first design. This review systematically searched all relevant UK prison policy and government documents with regards to mother and child separation in prison and analysed the extent to which these documents draw on attachment theory. Following initial searches, 58 documents were thematically analysed. Attachment was implicitly referred to in most documents but only explicitly mentioned in four. Global themes identified included ‘separation as trauma’. However, document groups varied in focusing either on the mother or the child and there were no joint perspectives. Developing and researching specific attachment-informed interventions might be one way forward as would further attachment-based research in this area

Mother-infant separations in prison. A systematic attachment-focused review of the academic and grey literature

This review systematically searched UK academic and grey literature in relation to mother and child separation in prison. Attachment theory is referred to in current prison policy for mothers (PSO 4801, 2008), and could provide a framework linking policy and practice. Reviewing grey literature provided an opportunity to explore practice-based literature. 24 academic papers and 51 grey documents were reviewed. Use of attachment theory in the academic literature varied according to discipline, ranging from extensive use to no use. There was greater use of attachment theory in the grey literature. Despite linguistic differences, all documents highlighted the detrimental impact of separation on imprisoned mothers. However, specificity was lacking regarding support for mothers, and staff needs were overlooked. Given its use across the sparse research and practice literature, and its basis for policy, attachment theory could underpin theoretically informed support for imprisoned mothers separated from their infants and staff who support them

Fabrication and test of a space power boiler feed electromagnetic pump. Part 2: Test facility and performance test

A three-phase helical induction electromagnetic pump, designed for the boiler-feed pump of a potassium Rankine-cycle space power system, was built and tested. The pump was tested over a range of potassium temperatures from 900 to 1400 F, flow rates from 0.75 to 4.85 lb/sec, developed pressures up to 340 psi, net positive suction heads (NPSH) from 1 to 22 psi, and NaK coolant temperatures from 800 to 950 F. The maximum efficiency at the pump design point of 3.25 lb/sec flow rate, 240 psi developed pressure, 1000 F potassium inlet temperature, and 800 F NaK coolant temperature was 16.3 percent. The tests also showed successful operation of the pump at an NPSH as low as 1.5 psi without cavitating