1,158 research outputs found
IMPACT of Stafac® (Virginiamycin) on performance of heat-stressed finishing pigs
No full textGramm, B.R.; Nimmo, R.D.; Allee, G.L.. (2006). IMPACT of Stafac® (Virginiamycin) on performance of heat-stressed finishing pigs. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/157269
STAFAC® (VIRGINIAMYCIN) Improves Phosphorus and Other Mineral Digestibility in Pigs
No full textLindemann, M.D.; Agudelo, J.H.; Nimmo, R.D.; Gramm, B.R.. (2002). STAFAC® (VIRGINIAMYCIN) Improves Phosphorus and Other Mineral Digestibility in Pigs. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/160386
Methods for wavelet-based autonomous discrimination of multiple partial discharge sources
No full textRecent years have seen increased interest in the application of on-line condition monitoring of medium voltage networks as the need to maintain and operate ageing cable networks increases. Detection and analysis of partial discharge (PD) activity is generally used as an indicator of pre-breakdown processes that may be indicative of insulation degradation over time. A significant challenge for on-line monitoring is discrimination between multiple partial discharge sources that will often naturally exist in the data. To discriminate between PD sources each PD signal is represented as a feature vector and a clustering algorithm is used to identify clusters in the resulting feature vector space, often after dimensional reduction. Each cluster identified in the data corresponds to a distinct PD source. In this work a comparison of clustering algorithms and dimensional reduction techniques is performed to identify clusters for a variety of PD data sets, in all cases the feature vector is created using wavelet decomposition energies. The three clustering algorithms used were Density Based Spatial Clustering of Applications with Noise (DBSCAN), Ordering Points to Identify Clustering Structure (OPTICS) and Simple Statistics-based Near Neighbour clustering technique (SSNN). The two dimensional reduction techniques considered were Principal Component Analysis (PCA) and t Distributed Stochastic Neighbour Embedding (t SNE). At present the most commonly used combination of dimensional reduction technique and clustering algorithm for PD data are PCA and DBSCAN respectively. From the comparison performed in this work it was found that t SNE combined with OPTICS or SSNN were the most successful at clustering PD data. For use in practical situations SSNN is preferred over OPTICS as it requires only a single input parameter, which generally be hardcoded, leading to a completely autonomous technique. It is therefore suggested that a combination of t SNE and SSNN is particularly appropriate for discriminating PD sources
DETERMINATION OF THE ENERGY VALUE OF STAFAC® (VIRGINIAMYCIN) IN FINISHING PIG DIETS
No full textGaines, A.M.; Allee, G.L.; Ratliff, B.W.; Srichana, P.; Nimmo, R.D.; Gramm, B.R.. (2005). DETERMINATION OF THE ENERGY VALUE OF STAFAC® (VIRGINIAMYCIN) IN FINISHING PIG DIETS. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/157765
Classification and localisation of multiple partial discharge sources within a high voltage transformer winding
No full textPartial discharge (PD) analysis is widely adopted for assessing the condition of the insulation systems within high voltage (HV) transformers. Different PD sources have different effects on the insulation condition of HV transformers. In a typical field environment, multiple PD sources may occur in HV transformer simultaneously. Therefore, source classification is very important to identify the types of defects causing discharges in a HV transformer. In recent years, several classification techniques have been proposed for application in PD analysis. This paper proposes automatic techniques to classify and localize multiple PD sources within a HV transformer winding. The proposed processing technique relies on the assumption that the PD pulses generated from different defects exhibit unique waveform characteristics. Surface and void discharges which are the common types of defect events that may occur within HV transformer windings have been experimentally generated. Each pair combination was injected simultaneously into different locations along the HV transformer winding with analysis of two wideband radio frequency current transformers (RFCTs) data captured from each end of the winding. After PD pulses extraction and wavelet analysis, this paper presents two approaches using two different methods to accurately locate multiple PD sources within an HV transformer winding. The performances of the two approaches for this type of application are presented
Solution of the problem of composite charge using R.D.38
No full textIn this paper the author has solved the problem of internal ballistics of composite charge using 'R.D.38' method which is based upon the usual isothermal approximation. A linear law of burning has been assumed
Author index
No full textThe articles have been scanned in colour with a HP Scanjet 5590; 300dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.This is a continuation of the "Author and Subject Index to the Onderstepoort Journal
of Veterinary Science and Animal Industry (1933- l950)" and the "Onderstepoort Journal
of Veterinary Research (1951 - 1968)" which appeared in June 1969 and covers the period
1969 to 1973, i.e. Volumes 36 to 40.
As from 1974 (Volume 41) it is intended to furnish an Author and Subject Index
in Number 4 of each volume covering all four numbers for that particular year
Noise due to unsteady flow past trailing edges
No full textThis paper presents two-dimensional direct numerical simulations (DNS) of noise generated at trailing edges (TE) with zero thickness. The simulations are conducted specifying either no-slip or slip walls in order to investigate viscous effects. In both cases, small amplitude disturbances are introduced close to the inflow boundary that serve as pressure disturbances at the TE. DNS data reveals that the unsteady Kutta condition is not satisfied, irrespective of the wall boundary condition. However, it appears that the validity of the unsteady Kutta condition is not essential for making an accurate prediction of the far field noise. The far field pressure is predicted as a function of the surface pressure difference using a 2-D modification of Amiet's classical theory, and compared with the far field pressure computed directly. Directivity plots provide evidence that the presence of boundary layers and noise generated by an unsteady wake in the no-slip cases lead to smearing of individual lobes, and that the downstream pointing lobes in no-slip wall cases are probably due to nonlinear noise generation in the wake. The simulations are conducted using a high-order accurate numerical method which is free of upwinding, artificial dissipation or any form of explicit filtering, and employs a novel boundary treatment
Characteristic distribution and scale interaction of turbulence in a boundary layer
No full textThis work revisits the concept of turbulent boundary layers from a novel perspective on scale transfer. Turbulence production and dissipation together with the energy budgets are analyzed in the velocity gradient invariant phase space. In combination with filtering, the mechanism of scale coupling is investigated and illustrated for different characteristic flow topologies. The understanding of the scale coupling is important to model turbulence. Turbulence models describe the complex interaction of the scales of motion in a simplified form. The essential task of turbulence modeling is to capture the coupling of the modeled and unmodeled scales as well as the evolution of the modeled scales within the unmodeled flow. This work characterizes the scale coupling by focusing on the interfaces between modeled and unmodeled flow such as production and dissipation. The mechanisms that govern the evolution of the modeled quantities are investigated for their core properties and universal features. Direct numerical simulation (DNS) is carried out to obtain data of a compressible zero pressure-gradient flat plate turbulent boundary layer flow. This flow topology allows to unveil the effect of a wall on the coupling of scales and evolution of turbulence
Learning from One's Mistakes
No full textCreated by R.D. Lee for the Royal Statistics Society, this article describes an exercise, which highlights the effect of sampling without replacement in small populations, and leads to consideration of the relative importance of sample and population size when examining standard error. The author provides a number of exercises, an explanation of statistical errors and the importance of sample size. This is a brief, yet fine resource for those in the field of statistics
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