Modeling power grids

We present a method to construct random model power grids that closely match statistical properties of a real power grid. The model grids are more difficult to partition than a real grid.Comment: 9 pages, 5 figure

Study of Heat Pipe Thermal Performance with Internal Modified Geometry

The aim of this study was to investigate the effect of inserting a new internal tube packing (TP) on the thermal performance of a thermosyphon heat pipe (THP). The THP pipe was made from copper with an inner diameter of 17.4 mm and length of 600 mm. The new internal tube packing (TP) had a central copper disc with two copper tubes soldered onto both sides to transport vapor and condensate. The upper tube or riser had an inner diameter of 8.3 mm and was 300 mm long; it was connected to a hole in the disc from the upper side to transport the steam to the condenser section. The lower tube or downcomer had an inner diameter of 5 mm, was 225 mm long and was connected to the lower side of the disc to collect the condensate and transport it to the evaporator. The TP was inserted inside the THP to complete the design of the improved heat pipe (TPTHP). Experimental results showed that the TPTHP reduces the transit time from 16 to 11 min and the thermal resistance by 17–62% based on the input power and depending on the conditions of the THP. The results also showed that the inclination angle and filling ratio have no effect on the thermal resistance of the TPTHP

Outcomes of ceftriaxone compared with cefazolin or nafcillin/oxacillin for outpatient therapy for methicillin-sensitive Staphylococcus aureus bloodstream infections: Results from a large United States claims database

BACKGROUND: Ceftriaxone is a convenient option for methicillin-sensitive METHODS: In this retrospective cohort, a large insurance claims database was queried from 2010 to 2018 for adults with MSSA bloodstream infection (BSI). Patients discharged on OPAT on cefazolin or oxacillin/nafcillin were compared with ceftriaxone with respect to 90-day hospital readmission with the same infection category and 90-day all-cause readmission using logistic regression models. RESULTS: Of 1895 patients with MSSA BSI, 1435 (75.7%) patients received cefazolin, oxacillin, or nafcillin and 460 (24.3%) ceftriaxone. Readmission due to the same infection category occurred in 366 (19.3%), and all-cause readmission occurred in 535 (28.3%) within 90 days. Risk factors significantly associated with readmission with the same infection category were the oldest sampled age group (61-64 years: adjusted odds ratio [aOR], 1.47 [95% confidence interval {CI}, 1.01-2.14]), intensive care unit stay during index admission (aOR, 2.33 [95% CI, 1.81-3.01]), prosthetic joint infection (aOR, 1.96 [95% CI, 1.18-2.23]), central line-associated BSI (aOR, 1.72 [95% CI, 1.33-2.94]), and endocarditis (aOR, 1.63 [95% CI, 1.18-2.23]). Ceftriaxone was not associated with increased risk of readmission with the same infection category (aOR, 0.89 [95% CI, .67-1.18]), or 90-day all-cause readmission (aOR, 0.86 [95% CI, .66-1.10]) when compared with oxacillin/nafcillin/cefazolin. CONCLUSIONS: In this cohort of MSSA BSI patients discharged on OPAT, there were no differences in outcomes of readmission with the same infection and 90-day all-cause readmission in patients treated with ceftriaxone compared to oxacillin/nafcillin or cefazolin. Patients with complicated BSIs such as endocarditis and epidural abscess were more likely to be prescribed cefazolin or oxacillin/nafcillin

Molten Carbonate Fuel Cell Combined Heat, Hydrogen and Power System: Feedstock Analysis

AbstractBiogas is an untapped potential in regards to an alternative energy source. This immediately available resource will allow countries to reduce their greenhouse gas emissions, energy consumption, and reliance on fossil fuels. This energy source is created by anaerobic digestion of feedstock. Sources for feedstock include organic and inorganic waste, agricultural waste, animal by-products, and industrial waste. All of these sources of biogas are a renewable energy source. Specifically a fuel cell can utilize the methane present in biogas using integrated heat, power, and hydrogen systems. A study was performed concerning energy flow and resource availability to ascertain the type and source of feedstock to run a fuel cell system unceasingly while maintaining maximum capacity. After completion of this study and an estimation of locally available fuel, the FuelCell Energy 1500 unit (a molten carbonate fuel cell) was chosen to be used on campus. This particular fuel cell will provide electric power, thermal energy to heat the anaerobic digester, hydrogen for transportation, auxiliary power to the campus, and myriad possibilities for more applications. In conclusion, from the resource assessment study, a FuelCell Energy DFC1500TM unit was selected for which the local resources can provide 91% of the fuel requirements

Study of a Molten Carbonate Fuel Cell Combined Heat, Hydrogen and Power System: End-Use Application

To address the problem of fossil fuel usage and high greenhouse gas emissions at the Missouri University of Science and Technology campus, using of alternative fuels and renewable energy sources can lower energy consumption and greenhouse gas emissions. Biogas, produced by anaerobic digestion of wastewater, organic waste, agricultural waste, industrial waste, and animal by-products is a potential source of renewable energy. In this work, we have discussed the design of CHHP system for the campus using local resources. An energy flow and resource availability study is performed to identify the type and source of feedstock required to continuously run the fuel cell system at peak capacity. Following the resource assessment study, the team selects FuelCell Energy DFC1500™ unit as a molten carbonate fuel cell. The CHHP system provides electricity to power the university campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, back-up power and other needs. In conclusion, the CHHP system will be able to reduce fossil fuel usage, and greenhouse gas emissions at the university campus

Quisto Pericárdico Gigante a Imitar Dextrocardia na Telerradiografia de Tórax

Pericardial cysts are rare benign congenital malformations, usually small, asymptomatic and detected incidentally on chest X-ray as a mass located in the right costophrenic angle. Giant pericardial cysts are very uncommon and produce symptoms by compressing adjacent structures. In this report, the authors present a case of a symptomatic giant pericardial cyst incorrectly diagnosed as dextrocardia on chest X-ray

Soil resources and potential for agricultural development in Bahr El Jebel in southern Sudan, Jonglei Canal project area

The author has identified the following significant results. Fourteen LANDSAT scenes were used to produce mosaics of the 167, 474 sq km study area. These were black and white MSS 7 images and false color composite images. Five major soil-landscape units were delineated on the mosaics, and these were subdivided into a total of 40 soil mapping units. Aerial reconnaissance was useful in defining boundaries between mapping units and in estimating the proportion of the various soils which composed each mapping unit. Ground surveying permitted first-hand observation of major soils and sampling for quantitative laboratory analysis. Soil interpretations were made, including properties, potentials, and limitations

Different secretion patterns of matrix metalloproteinases and IL-8 and effect of corticotropin-releasing hormone in preterm and term cervical fibroblasts

The aims of the present study were to compare the levels of mRNA and protein expression of matrix metalloproteinase (MMP)-1, -3, -8 and -9 in human cervical tissue in preterm and term labor as well as not in labor and to determine if corticotropin-releasing hormone (CRH) has an effect on MMP-1, -3 and interleukin (IL)-8 secretion in both preterm and term cervical fibroblasts. Cervical biopsies were taken from 60 women: 18 at preterm labor, 7 at preterm not in labor, 18 at term labor and 17 at term not in labor. ELISA and Immulite were used for protein and real-time RT–PCR for mRNA analysis. Cervical fibroblast cultures were incubated for 18 h with different CRH concentrations (10−13–10−6 M). The mRNA expression of MMP-1, -3 and -9 was higher in laboring groups compared with term not in labor. Protein levels of MMP-8 and -9 were higher in term in labor group compared with non-laboring groups. There were no significant differences in mRNA and protein expression between the preterm and respective term control groups. CRH significantly increased secretion of IL-8 in preterm and term cervical fibroblasts compared with controls. The secretion of IL-8 and MMP-1 was significantly higher and MMP-3 secretion lower in preterm cervical fibroblasts. In conclusion, cervical ripening at preterm seems to be a similar inflammatory process as at term with CRH involved. However, preterm and term cervical fibroblasts might have different phenotypes based on different secretion patterns of IL-8, MMP-1 and MMP-3

Comment on "Theory and computer simulation for the equation of state of additive hard-disk fluid mixtures"

A flaw in the comparison between two different theoretical equations of state for a binary mixture of additive hard disks and Monte Carlo results, as recently reported in C. Barrio and J. R. Solana, Phys. Rev. E 63, 011201 (2001), is pointed out. It is found that both proposals, which require the equation of state of the single component system as input, lead to comparable accuracy but the one advocated by us [A. Santos, S. B. Yuste, and M. L\'{o}pez de Haro, Mol. Phys. 96, 1 (1999)] is simpler and complies with the exact limit in which the small disks are point particles.Comment: 4 pages, including 1 figur

A prospective randomized trial of tacrolimus and prednisone versus tacrolimus, prednisone and mycophenolate mofetil in primary adult liver transplantation: A single center report

Background. Tacrolimus (TAC) and mycophenolate mofetil (MMF) are currently approved immunosuppressants for prevention of rejection in liver transplantation (LTx). They have different modes of action and toxicity profiles, but the efficacy and safety of MMF in primary liver transplantation with TAC has not been determined. Methods. An Institutional Review Board-approved, open-label, single-center, prospective randomized trial was initiated to study the efficacy and toxicity of TAC and steroids (double-drug therapy (D)) versus TAC, steroids, and MMF (triple-drug therapy (T)) in primary adult LTx recipients. Both groups of patients were started on the same doses of TAC and steroids. Patients randomized to T also received 1 gm MMF twice a day. Results. Between August 1995 and May 1998, 350 patients were enrolled at a single center-175 in the D and 175 in the T groups. All patients were followed until May 1998, with a mean follow-up of 33.8±9.1 months. Using an intention-to-treat analysis, the 1-, 2-, 3-, and 4-year patient survival was 85.1%, 81.6%, 78.6%, and 75.8%, respectively, for D and 87.4%, 85.4%, 81.3%, and 79.9%, respectively, for T. The 4-year graft survival was 70% for D and 72.1% for T. Although the rate of acute rejection in the first 3 months was significantly lower for T than for D (28% for triple vs. 38.9% for double, P=0.03), the overall rate of rejection for T at the end of 1 year was not significantly lower than for the D (38.9% triple vs. 45.2% double). The median time to the first episode of rejection was 14 days for D versus 24 days for T (P=0.008). During the study period, 38 of 175 patients in D received MMF to control ongoing acute rejection, nephrotoxicity, and/or neurotoxicity. On the other hand, 103 patients in the T discontinued MMF for infection, myelosuppression, and/or gastrointestinal disturbances. The need for corticosteroids was less after 6 months for T and the perioperative need for dialysis was lower with use of MMF. Conclusion. This final report confirms similar patient survival and graft survival up to 4 years with a trend towards fewer episodes of rejection, lower need for steroids, and better perioperative renal function. However, the complex nature of LTx patients and their posttransplantation course prevents the routine application of MMF