4,318 research outputs found
Crashworthiness analysis and optimization of standard and windowed multi-cell hexagonal tubes
No full textRecently, multi-cell structures have received increased attention for crashworthiness applications due to their superior energy absorption capability. However, such structures were featured with high peak collapsing force (PCL) forming a serious safety concern, and this limited their application for vehicle structures. Accordingly, this paper proposes windowed shaped cuttings as a mechanism to reduce the high PCL of the multi-cell hexagonal tubes and systemically investigates the axial crushing of different windowed multi-cell tubes and also seeks for their optimal crashworthiness design. Three different multi-cell configurations were constructed using wall-to-wall (WTW) and corner-to-corner (CTC) connection webs. Validated finite element models were generated using explicit finite element code, LS-DYNA, and were used to run crush simulations on the studied structures. The crashworthiness responses of the multi-cell standard tubes (STs), i.e., without windows, and multi-cell windowed tubes (WTs) were determined and compared. The WTW connection type was found to be more effective for STs and less favorable for WTs. Design of experiments (DoE), response surface methodology (RSM), and multiple objective particle swarm optimization (MOPSO) tools were employed to find the optimal designs of the different STs and WTs. Furthermore, parametric analysis was conducted to uncover the effects of key geometrical parameters on the main crashworthiness responses of all studied structures. The windowed cuttings were found to be able to slightly reduce the PCL of the multi-cell tubes, but this reduction was associated with a major negative implication on their energy absorption capability. This work provides useful insights on designing effective multi-cell structures suitable for vehicle crashworthiness applications
Seven new species of the Botryosphaeriaceae from baobab and other native trees in Western Australia
No full textIn this study seven new species of the Botryosphaeriaceae are described from baobab (Adansonia gibbosa) and surrounding endemic tree species growing in the Kimberley region of northwestern Australia. Members of the Botryosphaeriaceae were predominantly endophytes isolated from apparently healthy sapwood and bark of endemic trees; others were isolated from dying branches. Phylogenetic analyses of ITS and EF1- sequence data revealed seven new species: Dothiorella longicollis, Fusicoccum ramosum, Lasiodiplodia margaritacea, Neoscytalidium novaehollandiae, Pseudofusicoccum adansoniae, P. ardesiacum and P. kimberleyense
NT-proBNP in systemic right ventricles: a new cutoff level for risk stratification?
No full textINTRODUCTION AND OBJECTIVES
The role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the risk prediction of patients with systemic right ventricles (sRV) is not well defined. The aim of this study was to analyze the prognostic value of NT-proBNP in patients with an sRV.
METHODS
The prognostic value of NT-proBNP was assessed in 98 patients from the SERVE trial. We used an adjusted Cox proportional hazards model, survival analysis, and c-statistics. The composite primary outcome was the occurrence of clinically relevant arrhythmia, heart failure, or death. Correlations between baseline NT-proBNP values and biventricular volumes and function were assessed by adjusted linear regression models.
RESULTS
The median age [interquartile range] at baseline was 39 [32-48] years and 32% were women. The median NT-proBNP was 238 [137-429] ng/L. Baseline NT-proBNP concentrations were significantly higher among the 20 (20%) patients developing the combined primary outcome compared with those who did not (816 [194-1094] vs 205 [122-357]; P = .003). In patients with NT-proBNP concentrations > 75th percentile (> 429 ng/L), we found an exponential increase in the sex- and age-adjusted hazard ratio for the primary outcome. The prognostic value of NT-proBNP was comparable to right ventricular ejection fraction and peak oxygen uptake on exercise testing (c-statistic: 0.71, 0.72 and 0.71, respectively).
CONCLUSIONS
In patients with sRVs, NT-proBNP concentrations correlate with sRV volumes and function and may serve as a simple tool for predicting adverse outcomes
Predicting growth rates of interfaces and internal layers in a turbulent boundary layer using a first order jump model
No full textExperimental research is presented on the characteristics of interfaces and internal layers that are present in a turbulent boundary layer (TBL). Both the turbulent non-turbulent interface (T/NT) and internal shear layers are detected in snapshots of the stereo-PIV data. It turns out that the internal layers exhibit similar characteristics compared to the T/NT interface. A theoretical approximation of the large scale boundary layer growth indicates that the correct boundary layer growth can be obtained by employing a modified first order jump model on the conditional statistics. Employing the same framework to the internal shear layers indicates that shear layers tend to move slower in close proximity to the wall, whereas they accelerate when moving away from the wall. Based on previous research it is believed that these internal layers separate large regions of approximately uniform momentum. Hence, boundary entrainment velocities may be interpreted as growth rates of large scale motions in a TBL
An epistle to the author of The four farthing candles: By the author of The Rosciad of C-v-nt-G-rd-n.
No full text12p. ; 4⁰.The author of The Rosciad of C-v-nt-G-rd-n = Charles Churchill.With a half-title.Reproduction of original from the Huntington Library.English Short Title Catalog, ESTCN1512.Electronic data. Farmington Hills, Mich. : Thomson Gale, 2003. Page image (PNG). Digitized image of the microfilm version produced in Woodbridge, CT by Research Publications, 1982-2002 (later known as Primary Source Microfilm, an imprint of the Gale Group)
NT P1268 Dunmarra Thorium Grid Geodetic
No full textMaintenance and Update Frequency: notPlannedStatement: This NT P1268 Dunmarra Thorium Grid Geodetic is an airborne-derived radiometric thorium grid for the Dunmarra, NT, 2014. The survey was acquired under the project No. 1268 for the geological survey of NT. The grid has a cell size of 0.00083 degrees (approximately 91m). A total of 104017 line-kilometres of data at a line spacing of 400m and 80m terrain clearance were acquired to produce this grid. This radiometric thorium grid shows thorium element concentration of the Dunmarra, NT, 2014 in units of parts per million (or ppm). Noise-adjusted singular value decomposition (NASVD) has been applied to the data. NASVD is a spectral component analysis procedure for the removal of noise from gamma-ray spectra. Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). This Index is also available online at http://pid.geoscience.gov.au/dataset/79134.
Reference:
Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.<br/>This radiometric thorium grid has a cell size of 0.00083 degrees (approximately 91m) and shows thorium element concentration of the Dunmarra, NT, 2014 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2014 by the NT Government, and consisted of 104017 line-kilometres of data at 400m line spacing and 80m terrain clearance
NT intervention and income quarantining
No full textLooking at both social and legal issues, this Brief considers the history associated with the NT intervention and income quarantining. By analysing past policy, the author concludes that it is the marginalised and disadvantaged who suffer most from punitive, disempowering measures such as income quarantining
Hybrid single node genetic programming for symbolic regression
No full textThis paper presents a first step of our research on designing an effective and efficient GP-based method for symbolic regression. First, we propose three extensions of the standard Single Node GP, namely (1) a selection strategy for choosing nodes to be mutated based on depth and performance of the nodes, (2) operators for placing a compact version of the best-performing graph to the beginning and to the end of the population, respectively, and (3) a local search strategy with multiple mutations applied in each iteration. All the proposed modifications have been experimentally evaluated on five symbolic regression benchmarks and compared with standard GP and SNGP. The achieved results are promising showing the potential of the proposed modifications to improve the performance of the SNGP algorithm. We then propose two variants of hybrid SNGP utilizing a linear regression technique, LASSO, to improve its performance. The proposed algorithms have been compared to the state-of-the-art symbolic regression methods that also make use of the linear regression techniques on four real-world benchmarks. The results show the hybrid SNGP algorithms are at least competitive with or better than the compared methods.Accepted Author Manuscript. Revised version of a selected paper from IJCCI 2015.OLD Intelligent Control & Robotic
Dunmarra, NT, 2014 (P1268), elevation line data
No full textMaintenance and Update Frequency: notPlannedStatement: This Dunmarra, NT, 2014 (P1268), elevation line data is an airborne-derived elevation data for the Dunmarra, NT, 2014. The survey was acquired under the project No. 1268 for the geological survey of NT. A total of 104017 line-kilometres of data at a line spacing of 400m and 80m terrain clearance were acquired during this survey. The elevation data was calculated using the altimeters and Global Positioning System (GPS) sensor used for the benefit airborne of magnetic and radiometric data on the same survey. The elevation is the height relative to the Australian Height Datum GDA94 (AUSGEOID09). Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). This Index is also available online at http://pid.geoscience.gov.au/dataset/79134.
Reference:
Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).The Digital Elevation Model represents ground surface topography between points of known elevation. The elevation data was calculated using the altimeters and Global Positioning System (GPS) sensor used for the benefit of airborne magnetic and radiometric data on the same survey. The elevation is the height relative to the Australian Height Datum GDA94 (AUSGEOID09). The processed elevation data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.<br/> These line dataset from the Dunmarra, NT, 2014 survey were acquired in 2014 by the NT Government, and consisted of 104017 line-kilometres of data at 400m line spacing and 80m terrain clearance
On the dangers of decentralization
No full textThe author highlights some of the dangers of decentralizations. The benefits of decentralization in allocative efficiency are not as obvious as suggested by the standard theory of fiscal federalism. The assumptions of this theory are fragile. These doubtful benefits might carry a cost in production efficiency, but more empirical research is needed on this point. What is not doubtful is that decentralization runs counter to redistribution and stabilization. Decentralization makes redistributive policies, whether interpersonal or interjurisdictional, more difficult, if not impossible. Decentralization also makes macroeconomic stabilization programs more difficult to implement because subnational government fiscal policies can run counter to national policies. Serious drawbacks or potential drawbacks should be considered in designing any decentralization program. The arguments that the author develops make it easier to understand some of the real choices. These choices are not so much whether to decentralize in general but rather what functions to decentralize - in which sectors, and in which regions. Guidelines can be provided on this. Often, the problem is not so much whether a certain service should be provided by a central, regional, or local government, since the service often has to be provided with the intervention of all three levels of government. The real challenge is how to organize the joint production of the service. Decentralization refers simultaneously to a state and to a process. The virtues and dangers of decentralization are often discussed simultaneously for both concepts. This is a dangerous confusion because decentralization is path-dependent. What is desirable in a given country at a certain point in time depends on the present state of decentralization and the speed at which it has been reached. Much more work, particularly empirical work, is needed -- in review of decentralization (or centralization) experiences in general, as well as those encouraged or supported by the World Bank.National Governance,Banks&Banking Reform,Municipal Financial Management,Economic Theory&Research,Pharmaceuticals&Pharmacoeconomics
- …
