Utility spot pricing study : Wisconsin

Spot pricing covers a range of electric utility pricing structures which relate the marginal costs of electric generation to the prices seen by utility customers. At the shortest time frames prices change every five minutes--the same time frame as used in utility dispatch--longer time frames might include 24-hour updating in which prices are set one day in advance but vary hourly as a function of projected system operating costs. The critical concept is that customers see and respond to marginal rather than average costs. In addition the concept of spot pricing includes a "quality of supply" component by which prices are increased at times in which the system is approaching maximum capacity, thus providing a pricing mechanism to replace or augment rationing.This research project evaluated the potential for spot pricing of industrial customers from the perspective both of the utility and its customers. A prototype Wisconsin (based on the WFPCO system) and its industrial customers was evaluated assuming 1980 demand level and tariff structures. The utility system was simplified to include limited interconnection and exchange of power with. surrounding utilities. The analysis was carried out using an hourly simulation model, ENPRO, to evaluate the marginal operating cost for any hour. The industrial energy demand was adjusted to reflect the price (relative to the present time-of-use pricing system). The simulation was then rerun to calculate the change in revenues (and customer bill) and the amount of consumer surplus generated.A second analysis assumed a 5 percent increase in demand with no increase in capacity. Each analysis was carried out for an assumed low and high industrial response to price changes.In an effort to generalize beyond the Wisconsin data and to evaluate the likely implications of a flexible pricing scheme relative to a utility system with a greater level of oil generation, particularly on the margin, the system capacity of the study utility was altered by substitution of a limited number of coal plants by identical but with higher-fuel cost oil-fired plants. The analyses for the modified utility structure are parallel to those for the standard utility structure discussed above.The results of the analysis showed that the flexible pricing system produced both utility and customer savings. At lower capacity utilization the utility recovered less revenue than it did under the present time-of-use rates. While at higher utilization it recovered more. Under all scenarios tested, consumer surplus benefits were five to ten times greater than were simple fuel savings for the utility. While these results must be evaluated in additional testing of specific customer response patterns, it is significant to note that the ability of the customer to choose his pattern more flexibly holds a significant potential for customers to achieve greater surplus--even if their bill may in fact increase. These results are discussed in detail in the report as are a number of customer bill impact considerations and the issues associated with revenue reconciliation

Stagnation temperature measurement using thin-film platinum resistance sensors

The measurement of stagnation temperature in high-speed flows is an important aspect of gas turbine engine testing. The ongoing requirement to improve the accuracy of such measurements has led to the development of probe systems that use a thin-film platinum resistance thermometer (PRT) as the sensing element. For certain aspects of engine testing this type of sensing device potentially offers superior measurement performance to the thermocouple, the temperature sensor of choice in most gas turbine applications. This paper considers the measurement performance of prototype PRT-based stagnation temperature probes, up to high-subsonic flow conditions, using passively aspirated probe heads. The relatively poor temperature recovery performance of a simply constructed probe has led to the development of a new design that is intended to reduce the impact of thermal conduction within the probe assembly. The performance of this so-called dual-skin probe has been measured through a series of tests at a range of Mach numbers, incidence angles and Reynolds numbers. The data reveal that a high probe recovery factor has been achieved with this device, and that the application of this design to engine tests would yield the measurement performance benefits of the PRT whilst requiring small levels of temperature recovery compensation

Combination probes for stagnation pressure and temperature measurements in gas turbine engines

During gas turbine engine testing, steady-state gas-path stagnation pressures and temperatures are measured in order to calculate the efficiencies of the main components of turbomachinery. These measurements are acquired using fixed intrusive probes, which are installed at the inlet and outlet of each component at discrete point locations across the gas-path. The overall uncertainty in calculated component efficiency is sensitive to the accuracy of discrete point pressures and temperatures, as well as the spatial sampling across the gas-path. Both of these aspects of the measurement system must be considered if more accurate component efficiencies are to be determined. High accuracy has become increasingly important as engine manufacturers have begun to pursue small gains in component performance, which require efficiencies to be resolved to within less than ±1%. This article reports on three new probe designs that have been developed in a response to this demand. The probes adopt a compact combination arrangement that facilitates up to twice the spatial coverage compared to individual stagnation pressure and temperature probes. The probes also utilise novel temperature sensors and high recovery factor shield designs that facilitate improvements in point measurement accuracy compared to standard Kiel probes used in engine testing. These changes allow efficiencies to be resolved within ±1% over a wider range of conditions than is currently achievable with Kiel probes

Frequency of blood glucose monitoring in relation to glycaemic control: observational study with diabetes database

Objectives: To investigate patterns of self monitoring of blood glucose concentration in diabetic patients who use insulin and to determine whether frequency of self monitoring is related to glycaemic control. Setting: Diabetes database, Tayside, Scotland. Subjects: Patients resident in Tayside in 1993­-5 who were using insulin and were registered on the database and diagnosed with insulin dependent (type 1) or non­insulin dependent (type 2) diabetes before 1993. Main outcome measures: Number of glucose monitoring reagent strips dispensed (reagent strip uptake) derived from records of prescriptions. First recorded haemoglobin A1c concentration in the study period, and reagent strips dispensed in the previous 6 months. Results: Among 807 patients with type 1 diabetes, 128 (16%) did not redeem any prescriptions for glucose monitoring reagent strips in the 3 year study period. Only 161 (20%) redeemed prescriptions for enough reagent strips to test glucose daily. The corresponding figures for the 790 patients with type 2 diabetes who used insulin were 162 (21%; no strips) and 131 (17%; daily tests). Reagent strip uptake was influenced both by age and by deprivation category. There was a direct relation between uptake and glycaemic control for 258 patients (with recorded haemoglobin A1c concentrations) with type 1 diabetes. In a linear regression model the decrease in haemoglobin A1c concentration for every extra 180 reagent strips dispensed was 0.7%. For the 290 patients with type 2 diabetes who used insulin there was no such relation. Conclusions: Self monitoring of blood glucose concentration is associated with improved glycaemic control in patients with type 1 diabetes. Regular self monitoring in patients with type 1 and type 2 diabetes is uncommon

Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using 153Sm, 90Y, and 117mSn

Wendt, Richard E. III; Selting, Kimberly A.; Lattimer, Jimmy C.; Wong, Janine; Simón, Jaime; Stevenson, Nigel R.; Stearns, Stanley D.. Radiation Safety Considerations in the Treatment of Canine Skeletal Conditions Using 153Sm, 90Y, and 117mSn. Health Physics: June 2020 - Volume 118 - Issue 6 - p 702-710 doi: 10.1097/HP.0000000000001222https://openworks.mdanderson.org/mdacc_imgphys_pubs/1001/thumbnail.jp

The Relationship Between Fractures and DXA Measures of BMD in the Distal Femur of Children and Adolescents With Cerebral Palsy or Muscular Dystrophy

Children with limited or no ability to ambulate frequently sustain fragility fractures. Joint contractures, scoliosis, hip dysplasia, and metallic implants often prevent reliable measures of bone mineral density (BMD) in the proximal femur and lumbar spine, where BMD is commonly measured. Further, the relevance of lumbar spine BMD to fracture risk in this population is questionable. In an effort to obtain bone density measures that are both technically feasible and clinically relevant, a technique was developed involving dual-energy X-ray absorptiometry (DXA) measures of the distal femur projected in the lateral plane. The purpose of this study is to test the hypothesis that these new measures of BMD correlate with fractures in children with limited or no ability to ambulate. The relationship between distal femur BMD Z-scores and fracture history was assessed in a cross-sectional study of 619 children aged 6 to 18 years with muscular dystrophy or moderate to severe cerebral palsy compiled from eight centers. There was a strong correlation between fracture history and BMD Z-scores in the distal femur; 35% to 42% of those with BMD Z-scores less than −5 had fractured compared with 13% to 15% of those with BMD Z-scores greater than −1. Risk ratios were 1.06 to 1.15 (95% confidence interval 1.04–1.22), meaning a 6% to 15% increased risk of fracture with each 1.0 decrease in BMD Z-score. In clinical practice, DXA measure of BMD in the distal femur is the technique of choice for the assessment of children with impaired mobility. © 2010 American Society for Bone and Mineral Researc

Many-body physics of a quantum fluid of exciton-polaritons in a semiconductor microcavity

Some recent results concerning nonlinear optics in semiconductor microcavities are reviewed from the point of view of the many-body physics of an interacting photon gas. Analogies with systems of cold atoms at thermal equilibrium are drawn, and the peculiar behaviours due to the non-equilibrium regime pointed out. The richness of the predicted behaviours shows the potentialities of optical systems for the study of the physics of quantum fluids.Comment: Proceedings of QFS2006 conference to appear on JLT

Detectability of gravitational wave events by spherical resonant-mass antennas

We have calculated signal-to-noise ratios for eight spherical resonant-mass antennas interacting with gravitational radiation from inspiralling and coalescing binary neutron stars and from the dynamical and secular bar-mode instability of a rapidly rotating star. We find that by using technology that could be available in the next several years, spherical antennas can detect neutron star inspiral and coalescence at a distance of 15 Mpc and the dynamical bar-mode instability at a distance of 2 Mpc.Comment: 39 pages, 4 EPS Figures, some additional SNRs for secular instabilities, some changes to LIGO SNRs, Appendix added on the asymptotic expansion of energy sensitivity, corrected supernova rates. Results available at http://www.physics.umd.edu/rgroups/gen_rel_exp/snr.html Submitted to Phys. Rev.

Lifelong Fitness in Ambulatory Children and Adolescents with Cerebral Palsy I: Key Ingredients for Bone and Muscle Health

Physical activity of a sufficient amount and intensity is essential to health and the prevention of a sedentary lifestyle in all children as they transition into adolescence and adulthood. While fostering a fit lifestyle in all children can be challenging, it may be even more so for those with cerebral palsy (CP). Evidence suggests that bone and muscle health can improve with targeted exercise programs for children with CP. Yet, it is not clear how musculoskeletal improvements are sustained into adulthood. In this perspective, we introduce key ingredients and guidelines to promote bone and muscle health in ambulatory children with CP (GMFCS I–III), which could lay the foundation for sustained fitness and musculoskeletal health as they transition from childhood to adolescence and adulthood. First, one must consider crucial characteristics of the skeletal and muscular systems as well as key factors to augment bone and muscle integrity. Second, to build a better foundation, we must consider critical time periods and essential ingredients for programming. Finally, to foster the sustainability of a fit lifestyle, we must encourage commitment and self-initiated action while ensuring the attainment of skill acquisition and function. Thus, the overall objective of this perspective paper is to guide exercise programming and community implementation to truly alter lifelong fitness in persons with CP

A comparison of the prognostic value of composite ratios and cumulative scores in patients with operable rectal cancer

The aim of this study was to directly compare the prognostic value of cumulative scores and composite ratios in patients with operable rectal cancer. Within a single surgical unit preoperative differential blood cell results including neutrophil (N), lymphocyte (L), monocyte (M) and platelet (P) counts, as well as CRP (C) and albumin (A) levels were recorded. These results were used to construct a series of composite ratios (NLR, PLR, LMR, CAR) and cumulative scores (NLS, PLS, LMS, NPS, mGPS). The relationship between composite ratios and the cumulative scores and clinicopathological characteristics, cancer specific survival (CSS) and overall survival (OS) were examined. A total of 413 patients were included. When adjusted for TNM stage, surgical approach, time of surgery and margin involvement mGPS (p < 0.05) was associated with CSS. In addition, most composite ratios/scores showed correlations with neoadjuvant therapy (p < 0.001). When a direct comparison between NPS (myeloid) and mGPS (liver) was carried out they showed similar associations with both CSS and OS. Therefore, both composite ratios and cumulative scores have been shown to be prognostic in patients with operable rectal cancer