11,211 research outputs found
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Compensation for Uneven Surfaces When Building Laser Deposited Structures
Direct Laser Deposition (DLD) is a blown-powder laser deposition process that can be
used to quickly produce, modify or repair fully-dense metallic parts by a layered manufacturing
method. However, uneven substrate surfaces often cause variation in the deposited layer which
is magnified by succeeding layers. Research carried out at the University of Liverpool has
resulted in a non-feedback layer height controlling process based on controlling the shape of the
powder streams emitted from a four-port side feed nozzle. This method limits deposited layer
height by causing a sharp reduction of catchment efficiency in the vertical plane at a fixed
distance from the powder feed nozzle, and is therefore capable of depositing a consistent layer
height in spite of power, powder flow or process velocity variation. This paper demonstrates
how this method of layer height control can compensate for irregular substrate surfaces in the
production of accurate DLD parts.Mechanical Engineerin
Whole Farm Economic Evaluation of No-Till Rice Production in Arkansas
Rice in Arkansas is typically produced using intensive tillage. No-till rice has been studied, but the research focus has been limited to impacts on yields and per acre net returns. This analysis evaluates the profitability of no-till rice at the whole-farm level using both enterprise budget analysis and linear programming.Crop Production/Industries,
Automated Retrieval of Non-Engineering Domain Solutions to Engineering Problems
Organised by: Cranfield UniversityBiological inspiration for engineering design has occurred through a variety of techniques such as creation
and use of databases, keyword searches of biological information in natural-language format, prior
knowledge of biology, and chance observations of nature. This research focuses on utilizing the reconciled
Functional Basis function and flow terms to identify suitable biological inspiration for function based design.
The organized search provides two levels of results: (1) associated with verb function only and (2) narrowed
results associated with verb-noun (function-flow). A set of heuristics has been complied to promote efficient
searching using this technique. An example for creating smart flooring is also presented and discussed.Mori Seiki – The Machine Tool Compan
Effect of forward motion on engine noise
Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground
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Disrupted white matter in language and motor tracts in developmental stuttering
White matter tractsc onnecting areas involved in speech and motor control were examined using diffusion-tensor imagingingin a sample of peoplewhostutter (n=29) who were heterogeneous with respect to age, sex, handedness and stuttering severity. The goals were to replicate previous findings in developmental stuttering and to extend ourknowledge by evaluating the relationship between white matter differences in people who stutter and factors such as age, sex, handedness and stuttering severity. We replicated previous findings that showed reduced integrity in white matter underlying ventral premotorcortex,
cerebral peduncles and posteriorcorpus callosum in people who stutter, relative to controls. Tractography analysis additionally revealed significantly reduced white matter integrity in the arcuate fasciculus bilaterally and the left corticospinal tract and significantly reduced connectivity within theleft corticobulbar tract in people who stutter. Region-of-interest analyses revealed
reduced white matter integrity in people whostutter in the three pairs ocerebellar peduncles thatcarry the afferent and efferent fibers of the cerebellum. Within thegroup of people who stutter, the higher the stuttering severity index, the lower the white matter integrity in the leftangular gyrus but the greater the white matter connectivity in theleft corticobulbartract. Also,in people who stutter, handedness and age predicted the integrity of the corticospinal tract and peduncles, respectively. Further studies are needed to determine which of these white matter differences relate to the neural
basis of stuttering and which reflect experience-dependent plasticity
Content & Watkins's account of natural axiomatizations
This paper briefly recounts the importance of the notion of natural axiomatizations for explicating hypothetico-deductivism, empirical significance, theoretical reduction, and organic fertility. Problems for the account of natural axiomatizations developed by John Watkins in Science and Scepticism and the revised account developed by Elie Zahar are demonstrated. It is then shown that Watkins's account can be salvaged from various counter-examples in a principled way by adding the demand that every axiom of a natural axiomatization should be part of the content of the theory being axiomatized. The crucial point here is that content cannot simply be identified with the set of logical consequences of a theory, but must be restricted to a proper subset of the consequence set. It is concluded that the revised Watkins account has certain advantages over the account of natural axiomatizations offered in Gemes (1993)
Validity and Reliability of Electronic Devices to Measure Muscular Power during Linear Weight Lifting Movements
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Detecting gravitational waves from test-mass bodies orbiting a Kerr black hole with P-approximant templates
In this study we apply post-Newtonian (T-approximants) and resummed
post-Newtonian (P-approximants) to the case of a test-particle in equatorial
orbit around a Kerr black hole. We compare the two approximants by measuring
their effectualness (i.e. larger overlaps with the exact signal), and
faithfulness (i.e. smaller biases while measuring the parameters of the signal)
with the exact (numerical) waveforms. We find that in the case of prograde
orbits, T-approximant templates obtain an effectualness of ~0.99 for spins q <
0.75. For 0.75 < q < 0.95, the effectualness drops to about 0.82. The
P-approximants achieve effectualness of > 0.99 for all spins up to q = 0.95.
The bias in the estimation of parameters is much lower in the case of
P-approximants than T-approximants. We find that P-approximants are both
effectual and faithful and should be more effective than T-approximants as a
detection template family when q > 0. For q < 0 both T- and P-approximants
perform equally well so that either of them could be used as a detection
template family. However, for parameter estimation, the P-approximant templates
still outperforms the T-approximants.Comment: 11 Pages - 9 figures. Accepted for publication. Proceedings of GWDAW
9. Special edition of Classical and Quantum Gravit
The age of the Tojeira Formation (Late Jurassic, Early Kimmeridgian), of Montejunto, west-central Portugal
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