Providing decision support for the condition-based maintenance of circuit breakers through data mining of trip coil current signatures

The focus of this paper centers on the condition assessment of 11kV-33kV distribution circuit breakers from the analysis of their trip coil current signatures captured using an innovative condition monitoring technology developed by others. Using available expert knowledge in conjunction with a structured process of data mining, thresholds associated with features representing each stage of a circuit breaker's operation may be defined and used to characterize varying states of circuit breaker condition. Knowledge and understanding of satisfactory and unsatisfactory breaker condition can be gained and made explicit from the analysis of captured trip signature data and subsequently used to form the basis of condition assessment and diagnostic rules implemented in a decision support system, used to inform condition-based decisions affecting circuit breaker maintenance. This paper proposes a data mining method for the analysis of condition monitoring data, and demonstrates this method in its discovery of useful knowledge from trip coil data captured from a population of SP Power System's in-service circuit breakers. This knowledge then forms the basis of a decision support system for the condition assessment of these circuit breakers during routine trip testing

Cost Analysis and Water Conservation Potential of Irrigation Technologies in the Texas Panhandle Water Planning Area

Six irrigation systems are analyzed considering cost and potential water savings. The investment cost of furrow and drip is $115,800 and$260,120, respectively. The cost of quarter mile pivot ranges from $59,000 to$64,000. Per ac-in variable pumping cost ranges $9.96 to$14.86 assuming natural gas price $7.00 per MCF.Irrigation Technology, Ground Water Planning, Texas Panhandle, Water Conservation, Ogallala, Agribusiness, Environmental Economics and Policy, Farm Management, Production Economics, Resource /Energy Economics and Policy,

An ultrasonic method for measuring fluid penetration rate into threaded contacts

Various methods have been employed to study the efficacy of multipurpose penetrating oils but these techniques do not investigate the rate which these oils penetrate surfaces. This paper outlines a novel, non-invasive ultrasonic method that provides a direct means of mapping fluid penetration in threaded systems. An apparatus with piezoelectric elements was developed to pulse ultrasonic waves into a nut specimen where the waves reflected from the threaded interface. The reflected signal amplitude shifted as fluid penetrated the thread, allowing the fluid to be mapped to provide a measure of ingress rate. The results for three fluid samples are presented. Measurements suggest the fluid tracks helically down the unloaded side of the thread and radially into the loaded thread surfaces

Resummation Methods at Finite Temperature: The Tadpole Way

We examine several resummation methods for computing higher order corrections to the finite temperature effective potential, in the context of a scalar $\phi^4$ theory. We show by explicit calculation to four loops that dressing the propagator, not the vertex, of the one-loop tadpole correctly counts ``daisy'' and ``super-daisy'' diagrams.Comment: 18 pages, LaTeX, CALT-68-1858, HUTP-93-A011, EFI-93-2

Complete two-loop effective potential approximation to the lightest Higgs scalar boson mass in supersymmetry

I present a method for accurately calculating the pole mass of the lightest Higgs scalar boson in supersymmetric extensions of the Standard Model, using a mass-independent renormalization scheme. The Higgs scalar self-energies are approximated by supplementing the exact one-loop results with the second derivatives of the complete two-loop effective potential in Landau gauge. I discuss the dependence of this approximation on the choice of renormalization scale, and note the existence of particularly poor choices which fortunately can be easily identified and avoided. For typical input parameters, the variation in the calculated Higgs mass over a wide range of renormalization scales is found to be of order a few hundred MeV or less, and is significantly improved over previous approximations.Comment: 5 pages, 1 figure. References added, sample test model parameters listed, minor wording change

Improved results for N=(2,2) super Yang-Mills theory using supersymmetric discrete light-cone quantization

We consider the (1+1)-dimensional ${\cal N}=(2,2)$ super Yang--Mills theory which is obtained by dimensionally reducing ${\cal N}=1$ super Yang--Mills theory in four dimension to two dimensions. We do our calculations in the large-$N_c$ approximation using Supersymmetric Discrete Light Cone Quantization. The objective is to calculate quantities that might be investigated by researchers using other numerical methods. We present a precision study of the low-mass spectrum and the stress-energy correlator $$. We find that the mass gap of this theory closes as the numerical resolution goes to infinity and that the correlator in the intermediate $r$ region behaves like $r^{-4.75}$.Comment: 18 pages, 8 figure

Effects of stocking rate and corn gluten feed supplementation on performance of young beef cows grazing winter-stockpiled tall fescue-red clover pasture

A winter grazing experiment was conducted to evaluate the effects of stocking rate and corn gluten feed supplementation on forage mass and composition and the BW and BCS of bred 2-yr-old cows grazing stockpiled forage during winter. Two 12.2-ha blocks containing Fawn, endophyte-free, tall fescue and red clover were each divided into 4 pastures of 2.53 or 3.54 ha. Hay was harvested from the pastures in June and August of 2003 and 2004, and N was applied at 50.5 kg/ha at the initiation of stockpiling in August. On October 22, 2003, and October 20, 2004, twenty-four 30-mo-old Angus-Simmental and Angus cows were allotted by BW and BCS to strip-graze for 147 d at 0.84 or 1.19 cow/ha. Eight similar cows were allotted to 2 dry lots and fed tall fescue-red clover hay ad libitum. Corn gluten feed was fed to cows in 2 pastures to maintain a mean BCS of 5 (9-point scale) at each stocking rate and in the dry lots (high supplementation level) or when weather prevented grazing (low supplementation level) in the remaining 2 pastures at each stocking rate. Mean concentrations of CP in yr 1 and 2 and IVDMD in yr 2 were greater (P \u3c 0.10) in hay than stockpiled forage over the winter. At the end of grazing, cows fed hay in dry lots had greater (P \u3c 0.05) BCS in yr 1 and greater (P \u3c 0.10) BW in yr 2 than grazing cows. Grazing cows in the high supplementation treatment had greater (P \u3c 0.10) BW than cows grazing at the low supplementation level in yr 1. Cows in the dry lots were fed 2,565 and 2,158 kg of hay DM/cow. Amounts of corn gluten feed supplemented to cows in yr 1 and 2 were 46 and 60 kg/ cow and did not differ (P = 0.33, yr 1; P = 0.50, yr 2) between cows fed hay or grazing stockpiled forage in either year. Estimated production costs were greater for cows in the dry lots because of hay feeding

Effects of Self-Heating on Planar Heterostructure Barrier Varactor Diodes

The conversion efficiency for planar Al0.7GaAs-GaAs heterostructure barrier varactor triplers is shown to be reduced from a theoretical efficiency of 10% to 3% due to self-heating. The reduction is in accordance with measurements on planar Al0.7GaAs-GaAs heterostructure barrier varactor (HBV) triplers to 261 GHz at room temperature and with low temperature tripler measurements to 255 GHz. The delivered maximum output power at 261 GHz is 2.0 mW. Future HBV designs should carefully consider and reduce the device thermal resistance and parasitic series resistance. Optimization of the RF circuit for a 10 ?m diameter device yielded a delivered output power of 3.6 mW (2.5% conversion efficiency) at 234 GH

Repeat coronary angioplasty: Correlates of a second restenosis

AbstractTo identify the correlates of a second restenosis after repeat percutaneous coronary angioplasty, the records of 384 patients with single vessel disease who underwent repeat angioplasty for restenosis complicating a first elective angioplasty were examined. A second restenosis occurred in 47 (31%) of 151 patients having angiographic follow-up. Univariate correlates of a second restenosis were an interval between the first and the second angioplasty <5 months (41 versus 20% of patients had restenosis, p < 0.01), male gender (35 versus 12%, p < 0.05), lesion length ≥15 mm before the second angioplasty (62 versus 28%, p < 0.05), diameter stenosis >90% before the second angioplasty (67 versus 29%, p < 0.05), final gradient >20 mm Hg after the second angioplasty (52 versus 28%, p < 0.05) and an additional site requiring dilation at the time of the second angioplasty (50 versus 29%, p = 0.10).Multivarlate predictors of a second restenosis were an interval of <5 months between the first and the second angioplasty (p = 0.001), male gender (p = 0.001), lesion length ≥15 mm before the second angioplasty (p = 0.001) and the need to have an additional site dilated at the time of the second angioplasty (p = 0.002). Patients at increased risk of restenosis after the second angioplasty can be identified and may serve as a useful population for intervention studies