Energy efficient engine: Turbine intermediate case and low-pressure turbine component test hardware detailed design report

A four stage, low pressure turbine component has been designed to power the fan and low pressure compressor system in the Energy Efficient Engine. Designs for a turbine intermediate case and an exit guide vane assembly also have been established. The components incorporate numerous technology features to enhance efficiency, durability, and performance retention. These designs reflect a positive step towards improving engine fuel efficiency on a component level. The aerodynamic and thermal/mechanical designs of the intermediate case and low pressure turbine components are presented and described. An overview of the predicted performance of the various component designs is given

Material Flow Analysis: Outcome Focus (MFA:OF) for Elucidating the Role of Infrastructure in the Development of a Liveable City

Engineered infrastructures (i.e., utilities, transport & digital) underpin modern society. Delivering services via these is especially challenging in cities where differing infrastructures form a web of interdependencies. There must be a step change in how infrastructures deliver services to cities, if those cities are to be liveable in the future (i.e., provide for citizen wellbeing, produce less CO2 & ensure the security of the resources they use). Material Flow Analysis (MFA) is a useful methodology for understanding how infrastructures transfer resources to, within and from cities and contribute to the city’s metabolism. Liveable Cities, a five-year research programme was established to identify & test radical engineering interventions leading to liveable cities of the future. In this paper, the authors propose an outcome-focussed variation on the MFA methodology (MFA: OF), evidenced through work on the resource flows of Birmingham, UK. These flows include water, energy, food & carbon-intensive materials (e.g., steel, paper, glass), as well as their associated waste. The contribution MFA: OF makes to elucidating the interactions & interdependencies between the flows is highlighted and suggestions are made for how it can contribute to the (radical) rethinking of the engineered infrastructure associated with such flow

A polyphonic acoustic vortex and its complementary chords

Using an annular phased array of eight loudspeakers, we generate sound beams that simultaneously contain phase singularities at a number of different frequencies. These frequencies correspond to different musical notes and the singularities can be set to overlap along the beam axis, creating a polyphonic acoustic vortex. Perturbing the drive amplitudes of the speakers means that the singularities no longer overlap, each note being nulled at a slightly different lateral position, where the volume of the other notes is now nonzero. The remaining notes form a tri-note chord. We contrast this acoustic phenomenon to the optical case where the perturbation of a white light vortex leads to a spectral spatial distribution

Experience can increase prism fusion range

Aim: Differences in near prism fusion ranges (PFR) were assessed in 4 groups of participants who differed in experience of exposure to such testing. The effect of encouragement in the two least experienced groups was also tested. Methods: The near base in (BI) and base out (BO) fusional amplitudes (FA) were measured in four groups of 10 participants, all with normal or corrected to normal vision. One group was naÏve to such testing, being non-orthoptic students, the other three groups consisted separately of Year One, Two and Three student orthoptists. The two most inexperienced groups, NaÏve and Year One student orthoptists, were also tested a second time with encouragement to try as hard as possible to increase their fusion amplitudes. Results: Year Two and Year Three students had significantly ( p < 0.001, often over 20∆) larger BO FA than naÏve students or Year One orthoptic students. No such differences were seen for BI measures. Encouragement also significantly ( p < 0.01), but modestly (<6∆), increased BO FA and slightly (about 1∆, p < 0.05) increased BI FA. Conclusions: Experience did increase PFR but this was mainly in BO fusion amplitudes and was far greater than obtained by encouraging participants. The experience needed to obtain this increase appeared to be the exposure occurring in one year of training to be an orthoptist. Further experiments could help clarify the factors involved in this improvement by tracking any increase throughout this first year and also look for changes in performance in other orthoptic tests

Spherically Symmetric Solutions to Fourth-Order Theories of Gravity

Gravitational theories generated from Lagrangians of the form f(R) are considered. The spherically symmetric solutions to these equations are discussed, paying particular attention to features that differ from the standard Schwarzschild solution. The asymptotic form of solutions is described, as is the lack of validity of Birkhoff's theorem. Exact solutions are presented which illustrate these points and their stability and geodesics are investigated.Comment: 10 pages, published versio

Supersonic optical tunnels for Bose-Einstein condensates

We propose a method for the stabilisation of a stack of parallel vortex rings in a Bose-Einstein condensate. The method makes use of a hollow laser beam containing an optical vortex. Using realistic experimental parameters we demonstrate numerically that our method can stabilise up to 9 vortex rings. Furthermore we point out that the condensate flow through the tunnel formed by the core of the optical vortex can be made supersonic by inserting a laser-generated hump potential. We show that long-living immobile condensate solitons generated in the tunnel exhibit sonic horizons. Finally, we discuss prospects of using these solitons for analogue gravity experiments.Comment: 14 pages, 3 figures, published versio

Test Excavations at the Culebra Creek Site, 41BX126, Bexar County, Texas

Archaeological test excavations were undertaken at 4IBX126 on Culebra Creek to offset the impact from a proposed Texas Department of Transportation (TxDOT) highway improvement project on Loop 1604 in northwest Bexar County. Archaeological investigations were conducted in three field seasons: the first two seasons were conducted by TxDOT archaeologists and the third was directed by personnel from the Center for Archaeological Research (CAR) of The University of Texas at San Antonio. During the three projects, 55 hand-dug units, 29 backhoe trenches, 36 shovel tests, and eight Gradall trenches were excavated. Seventeen features were recorded; 25 radiocarbon assays were conducted; over 59,000 lithic artifacts were recovered and analyzed; 1,655 liters of sediment float samples were processed; 3,337 kg of burned rock were analyzed; and nearly 300 g of fatmal material and 25 archaeomagnetic samples were analyzed. The testing revealed utilization of the site in the Early, Middle, and Late Archaic periods. The analysis of materials and results of all three field efforts are presented in this single volume. Geoarchaeological investigations show that four terraces (TO, Tl, T2, and T3) in the immediate site area accumulated from the Late Pleistocene through the Holocene. Five Stratigraphic Units (I-V) make up these terraces and overlap one another. The T2 terrace is composed of Stratigraphic Units IT, ill, and IV, while the Tl terrace consists mostly of Stratigraphic Units IV and V. Archaeological materials were discovered in situ within the Tl and T3 terraces and primarily within Stratigraphic Units ill and IV. Radiocarbon assays indicate that Stratigraphic Unit IV formed between at least 4000-2000 B.P., Stratigraphic Unit ill accumulated between approximately 11,500-4000 B.P., and Stratigraphic Unit IT was accreting at least 17,500 years ago. Too little evidence exists to determine the full time ranges of sediment accumulation, and whether significant temporal gaps exist between the sedimentation of these geological units. Archaeological excavations focused on three separate areas: A, B, and C. Area A is a new right-of-way east of the existing right-of-way. Excavations in this area defined a Late Archaic Montell component dating to approximately 2700 B.P. These materials include two burned rock features in situ within Unit IV on the scarp of the T2 terrace. This area probably was occupied by a small residential group during the Late Archaic period. Area B is east of Loop 1604 in the existing right-of-way and on the T2 terrace. Area B contains a Middle Archaic Nolan component in the upper portion of Stratigraphic Unit ill, below a Late Archaic burned rock midden with a central subsurface oven in Unit IV. Area C is in the existing right-of-way west of Loop 1604. Excavations in this area investigated the possibility of an intact Early Archaic occupation; however, no evidence of one was found. In Area B, the Nolan component consisted of lithic artifacts scattered among small burned rock features that probably served as hearths. This component is radiocarbon dated to approximately 4600 B.P. The Late Archaic burned rock midden was apparently used between 4000 B.P. and 2000 B.P. Subfeatures within the central oven indicate multiple cooking events. Ethnographic evidence suggests earth ovens contained food wrapped with insulating material over a layer of hot rocks heated by a coal bed. This was capped with dirt to seal the oven. When cooking was complete, the earth cap is removed to reach the food. CAR conducted earth-oven hot-rock experiments which indicated that local limestone could be used once or at the most twice. Local hot-rock cooking should generate a great deal of burned limestone debris. The framework ofthe feature at 41BX126 represents the cap and rock heating-element dumpings from separate cooking events as well as a few small intact burned rock features that served as ovens or hearths. At the base of the midden were a few depressions that may represent borrow pits used to obtain sediment for the central oven cap. Mixing of temporally distinct artifacts from the Nolan and later occupations occurs in and beyond the midden due to sediment excavation and transportation across the site, and redeposition of materials through erosion of materials off the framework

Why the Realist-Instrumentalist Debate about Rational Choice Rests on a Mistake

Within the social sciences, much controversy exists about which status should be ascribed to the rationality assumption that forms the core of rational choice theories. Whilst realists argue that the rationality assumption is an empirical claim which describes real processes that cause individual action, instrumentalists maintain that it amounts to nothing more than an analytically set axiom or ‘as if’ hypothesis which helps in the generation of accurate predictions. In this paper, I argue that this realist-instrumentalist debate about rational choice theory can be overcome once it is realised that the rationality assumption is neither an empirical description nor an ‘as if’ hypothesis, but a normative claim