Effect of empennage arrangement on single-engine nozzle/afterbody static pressures at transonic speeds

An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to determine the effects on empennage arrangement on single-engine nozzle/afterbody static pressures. Tests were done at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.0 (jet off) to 8.0. and angles of attack from -3 to 9 deg (at jet off conditions), depending on Mach number. Three empennage arrangements (aft, staggered, and forward) were investigated. Extensive measurements were made of static pressure on the nozzle/afterbody in the vicinity of the tail surfaces

Understanding Current Signals Induced by Drifting Electrons

Consider an electron drifting in a gas toward a collection electrode. A common misconception is that the electron produces a detectable signal only upon arrival at the electrode. In fact, the situation is quite the opposite. The electron induces a detectable current in the electrode as soon as it starts moving through the gas. This induced current vanishes when the electron arrives at the plate. To illustrate this phenomenon experimentally, we use a gas-filled parallel plate ionization chamber and a collimated $^{241}$Am alpha source, which produces a track of a fixed number of ionization electrons at a constant distance from the collection electrode. We find that the detected signal from the ionization chamber grows with the electron drift distance, as predicted by the model of charge induction, and in conflict with the idea that electrons are detectable upon arrival at the collection plate.Comment: 21 pages, 12 figure

Highly excited ro-vibrational states of small molecules using discrete variable representations

Calculated ro-vibrational levels (J ≤ 4) and transition intensities are presented for 7Li+3 and 7Li2 6Li+. These studies are made using conventional Finite Basis Representation (FBR) methods. A formulation of the nuclear motion problem for small molecules is then presented in the Discrete Variable Representation (DVR). The theory is developed in a highly generalised set of internal co-ordinates using an exact Hamiltonian operator. Having used the DVR for vibrational (J = 0) calculations, it is rather simply extended to ro-vibrational (J > 0) case. It is demonstrated that the DVR is extremely powerful in dealing with molecules that can undergo very large amplitude (coupled) motions on what may be a particularly complicated potential energy surface. Calculations on the isomerising LiCN/LiNC system are presented using a 2D (CN frozen) potential energy surface. Some 900 vibrational levels are stabilised using a DVR in the angular co-ordinate of scattering (or Jacobi) co-ordinates. Contour plots of the wavefunctions are made and analysed; this yields information about the very highly excited dynamics of the system, well above the isomerisation barrier, for the very first time. Full three-mode calculations on the H+3 molecular ion are presented, using a very accurate ab initio potential energy surface. Ro-vibrational studies are made using a DVR in the angular co-ordinate of scattering co-ordinates. A multidimensional DVR in scattering co-ordinates is then employed and three H+3 surfaces are used. These calculations converge all the J = 0 bound states of the system to within 10cm-1, giving at least 881 states for each potential. The wavefunctions are analysed in an attempt to find assignablel or spatially localised states. The significance of these calculations to the unassigned near-dissociation spectra is discussed

A Spoonful Of Humor Helps The Lecture Go Down

The goal of every teacher is to connect with his or her audience.  Humor has a way of disarming the listener and opening up lines of communication.  The purpose of this paper is to give reasons for using, ways to incorporate and benefits of humor in the lecture.  Laughter is not only the best medicine, but does not require a prescription

Enhancing buildability through improving design-construction feedback loops within complex projects

Current attempts to answer the questions of how learning can be nurtured within projects; and, how it can be shared within the supply chain make a conscious stance in support of one of two seemingly conflicting perspectives. These are; a first generation knowledge management systems perspective, or a second generation socialisation perspective. This study shrewdly identifies that to categorically anchor to simply one perspective is fundamentally flawed. It is a strategy which regards each as mutually exclusive and therefore negates the advantages of its opposition. Each perspective is suited to differing needs. A first generation perspective satisfies the desire of organisations to create a tangible representation of their knowledge base. However, purely focusing on this need ignores the requirement of socialisation, which is essential for effective tacit knowledge transfer. This has astutely been identified as causing cycles of disillusionment due to its inevitable inability to perform effective knowledge sharing. In comparison, a purely second generation approach fails to satisfy the desire to produce a tangible resource base, which thus reduces the incentives for organisations to provide vital socialisation opportunities. It has been widely acknowledged that learning within projects is needed to make strides towards continuous improvement. If this is not the case, the industry will continue to repeat flawed practices or continuously reinvent solutions unnecessarily. This is resulting in significant inefficiencies within the industry, reduced quality outputs and supplying reduced value. Furthermore, it is not simply the case that learning within individual phases of the construction lifecycle, or within organisations will realise these benefits. For true efficiency benefits to be realised, knowledge and learning from projects has to be shared throughout the supply chain. This research s contribution has been established through the development of a feedback framework predominantly between construction and design teams throughout a project s lifecycle. The framework provides the capability to transfer lessons to not only individual organisations, but across organisational boundaries also. It seeks to improve internal knowledge management through incorporating critical facets such as live capture, multimedia formats and the ability to network with other knowledge owners/seekers. Accordingly, this project has made a significant theoretical contribution through identifying the ability and need to combine first and second generation knowledge management perspectives

An improved 1080 paste for control of possums (Trichosurus vulpecula)

A new 1080 paste (PTP) was developed by Pest-Tech Ltd. and then evaluated in a series of comparative trials with Pestoff possum paste (POP). The research indicated that PTP was significantly more palatable to captive possums than POP following 57 h of exposure to ‘hot’ conditions (hot conditions were 30°C for 6 h followed by 18 h at 13°C on a 24 h cycle). Acceptance by bees was low with significantly less PTP than POP removed by forager bees over a 30 h period. In the field, the control efficacy of both pastes was high (89%-94% kill), with no significant differences between treatments. Based on these results, it is recommend that PTP is registered for possum control in New Zealand

A critical assessment of different transmethylation procedures commonly employed in the fatty acid analysis of aquatic organisms

Several transmethylation procedures have been used for fatty acid analysis of aquatic organisms although the suitability of the applied procedures has rarely been tested. The aim of this study was to demonstrate how different derivatization procedures can affect the result of fatty acid analysis. Different transmethylation procedures based on the acidic catalysts boron trifluoride, concentrated sulphuric acid and anhydrous hydrochloric acid were applied to cold-pressed copepod oil and Atlantic salmon flesh lipids rich in wax esters and triacylglycerols, respectively. The results show that 1) the use of unsuitable catalysts and/or incubation conditions may influence the data obtained which can lead to inaccurate conclusions about the presence of fatty acids in aquatic organisms/ecosystems 2) different derivatization procedures based on the same catalyst can produce diverging results and 3) the efficiency of a selected catalyst/procedure should be verified (e.g. by thin-layer chromatography) to ensure the complete transmethylation of fatty acids

Coupled Cluster Channels in the Homogeneous Electron Gas

We discuss diagrammatic modifications to the coupled cluster doubles (CCD) equations, wherein different groups of terms out of rings, ladders, crossed-rings and mosaics can be removed to form approximations to the coupled cluster method, of interest due to their similarity with various types of random phase approximations. The finite uniform electron gas is benchmarked for 14- and 54-electron systems at the complete basis set limit over a wide density range and performance of different flavours of CCD are determined. These results confirm that rings generally overcorrelate and ladders generally undercorrelate; mosaics-only CCD yields a result surprisingly close to CCD. We use a recently developed numerical analysis [J. J. Shepherd and A. Gr\"uneis, Phys. Rev. Lett. 110, 226401 (2013)] to study the behaviours of these methods in the thermodynamic limit. We determine that the mosaics, on forming the Brueckner Hamltonian, open a gap in the effective one-particle eigenvalues at the Fermi energy. Numerical evidence is presented which shows that methods based on this renormalisation have convergent energies in the thermodynamic limit including mosaic-only CCD, which is just a renormalised MP2. All other methods including only a single channel, namely ladder-only CCD, ring-only CCD and crossed-ring-only CCD, appear to yield divergent energies; incorporation of mosaic terms prevents this from happening.Comment: 9 pages, 4 figures, 1 table. Comments welcome: [email protected]

Replacement of dietary fish oil with increasing levels of linseed oil: Modification of flesh fatty acid compositions in Atlantic salmon (Salmo salar) using a fish oil finishing diet

Five groups of Atlantic salmon smolts, of initial mean weight 127 ± 3g, were fed increasing levels of dietary linseed oil (LO) in a regression design. The control diet contained capelin oil (FO) only and the same oil was blended with LO to provide the experimental diets. After an initial growth period of 40 weeks all treatment groups were switched to a finishing diet containing only FO for a further 24 weeks. Growth, flesh total lipid content and astaxanthin content were not affected by dietary oil composition. The fatty acid compositions of flesh total lipids were linearly correlated with dietary fatty acid compositions (r2 = 0.88-1.00, P < 0.0001). Inclusion of the LO at 50% of added dietary lipid reduced flesh docosahexaenoic (22:6n-3; DHA) and eicosapentaenoic acids (20:5n-3; EPA) to 65 and 58%, respectively, of the concentrations in fish fed FO. When inclusion of dietary LO reached 100% the flesh DHA and EPA concentrations were reduced to 38 and 30%, respectively, of values in fish fed FO. Differences between diet fatty acid concentration and flesh fatty acid concentration showed that 16:0, 18:1n-9 and especially DHA were preferentially retained by salmon whereas 18:2n-6, 18:3n-3 and 22:1n-11 were selected against and presumably utilised for energy production. Feeding a finishing diet containing FO alone for 16 weeks restored flesh DHA and EPA concentrations in fish previously fed 50 and 100% LO to around 80% of their values in fish fed FO throughout. Flesh DHA and EPA concentrations in fish fed up to 50% LO were in excess of recommended intake values for these fatty acids. By utilising FO finishing diets for at least 16 weeks similar flesh DHA and EPA concentrations could be achieved in fish previously fed up to 100% LO for 40 weeks. This study suggests that LO can be used as a substitute for FO in salmon feeds during seawater growth and that any reductions in DHA and EPA can be overcome by feeding FO for a period before harvest