Effect of admixtures on the yield stresses of cement pastes under high hydrostatic pressures

When cement-based materials are transported at a construction site, they undergo high pressures during the pumping process. The rheological properties of the materials under such high pressures are unknown, and estimating the workability of the materials after pumping is a complex problem. Among various influential factors on the rheology of concrete, this study investigated the effect of mineral and chemical admixtures on the high-pressure rheology. A rheometer was fabricated that could measure the rheological properties while maintaining a high pressure to simulate the pumping process. The effects of superplasticizer, silica fume, nanoclay, fly ash, or ground granulated blast furnace slag were investigated when mixed with two control cement pastes. The water-to-cement ratios were 0.35 and 0.50.ope

Conservative Management of Spontaneous Isolated Dissection of the Superior Mesenteric Artery

Purpose. We report the clinical outcomes of patients with spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) who were treated conservatively. Materials and Methods. A retrospective review was performed in 14 patients from 2006 to 2016 with SIDSMA. Their clinical features and computed tomographic angiography (CTA) characteristics, treatment methods, and clinical outcomes were analyzed. The mean age was 53.6 (range, 41–73) years, and the mean follow-up duration was 20.6 (range, 1–54) months. Conservative management was the primary treatment if no bowel ischemia or arterial rupture was noted. Results. The mean initial abdominal visual analog pain score was 7 (range, 5–9) in seven patients. The mean total duration of abdominal pain was 10.2 days (range, 2–42 days) in 10 patients. The mean percentage stenosis of the dissected SMA at the initial presentation was 78.8% in 14 patients. Complete obstruction of the SMA at the initial presentation was evident in 4 of the 14 patients (28.6%). Conservative management was successful in all 14 patients. None of the 14 patients developed bowel ischemia or an infarction. Abdominal pain did not recur in any patient during follow-up (mean, 20.6 months; range, 1–54 months). Conclusion. Conservative management was successful for all SIDSMA patients, even those with severe compression of the true lumen or complete obstruction of the dissected SMA

Density functional calculations of the electronic structure and magnetic properties of the hydrocarbon K3picene superconductor near the metal-insulator transition

We have investigated the electronic structures and magnetic properties of of K3picene, which is a first hydrocarbon superconductor with high transition temperature T_c=18K. We have shown that the metal-insulator transition (MIT) is driven in K3picene by 5% volume enhancement with a formation of local magnetic moment. Active bands for superconductivity near the Fermi level E_F are found to have hybridized character of LUMO and LUMO+1 picene molecular orbitals. Fermi surfaces of K3picene manifest neither prominent nesting feature nor marked two-dimensional behavior. By estimating the ratio of the Coulomb interaction U and the band width W of the active bands near E_F, U/W, we have demonstrated that K3picene is located in the vicinity of the Mott transition.Comment: 5 pages, 5 figure

Under-reporting of Energy Intake from 24-hour Dietary Recalls in the Korean National Health and Nutrition Examination Survey

AbstractObjectivesChronic degenerative diseases are closely related to daily eating habits, nutritional status, and, in particular, energy intake. In clarifying these relationships it is very important for dietary surveys to report accurate information about energy intake. This study attempted to identify the prevalence of the under-reporting of energy intake and its related characteristics based on the Korean National Health and Nutrition Examination Survey conducted in the years 2007–2009.MethodsThe present study analyzed dietary intake data from 15,133 adults aged ≥19 years using 24-hour dietary recalls. Basal metabolic rates were calculated from the age- and gender-specific equations of Schofield and under-reporting was defined as an energy intake <0.9, represented by the ratio of energy intake to estimated basal metabolic rate.ResultsUnder-reporters (URs) accounted for 14.4% of men and 23.0% of women and the under-reporting rate was higher in the age group 30–49 years for both men and women. The results from an analysis of the age-specific socioeconomic characteristics of participants classified as URs showed that under-reporting was high in women living alone and in women with only elementary school education or no education. The results from an analysis of the health-specific characteristics of URs showed that a large proportion of URs had poor self-rated health or were obese, or both, compared with non-URs. The proportion of participants who consumed less than the estimated average requirements for nutrients was significantly higher in URs compared with non-URs.ConclusionThe under-reporting of energy intake was associated with age, gender, education level, income level, household status (single-person or multi-person), self-rated health, physical activity, and obesity

Optimal Synthesis of Horizontally Aligned Single-Walled Carbon Nanotubes and Their Biofunctionalization for Biosensing Applications

As an influential candidate for highly sensitive biomolecule sensor, which can capture disease related biomolecules, carbon nanotube is useful material due to its unique properties. To adopt as a sensing platform, it is strongly needed to find optimal refined synthetic condition. In order to find the optimal synthetic conditions of horizontally aligned CNT, we performed quantity control of themixed gases of H-2 and CH4 injected. We successfully find that the formation of amorphous-like carbon was critically affected by some gas condition such as the flow rate of injected gases and ratios of gas mixture. Moreover, it should be noted that our horizontally aligned carbon nanotube array platform developed would offer another potential in developing nanoscale light source, where light emission results from electron-hole carrier recombinationope

Usefulness and safety of the “God’s Hand” pneumatic compression device for hemostasis in femoral catheterization

PURPOSE :We aimed to assess the usefulness and safety of the God’s Hand pneumatic compression device for hemostasis in patients undergoing percutaneous endovascular procedures via femoral artery.METHODS:Two hundred thirty-seven patients in whom hemostasis of femoral catheterization was achieved using a God’s Hand pneumatic compression device were enrolled. The patients were divided into group A, those in whom the device was applied for four hours, and group B, those in whom the device was applied for two hours, with an additional two hours of bed rest in both groups. Groups A and B were regrouped to groups A’ and B’ using the propensity score matching method (n=65, for both). Chi-squared test and logistic regression models were used to analyze the relationship between the complication rate and patient characteristics and procedure-related factors.RESULTS:Clinical success was achieved in 216 of 237 patients (91.1%): 63 in group A (84%) and 153 in group B (94.4%); in propensity score matched groups, clinical success was seen in 47 patients in group A’ (81.5%) and 62 patients in group B’ (95.4%). Group B’ showed a higher clinical success rate than group A’ (P = 0.028). There were no major complications. In logistic regression models, a negative association was noted between the complication rate and the duration of God’s Hand application; however, this association was not statistically significant.CONCLUSION:The God’s Hand pneumatic compression device is effective and safe for the hemostasis of femoral catheterization, and four hours of bed rest is sufficient for hemostasis in selected patients

A Critical Heat Generation for Safe Nuclear Fuels after a LOCA

This study applies a thermo-elasto-plastic-creep finite element procedure to the analysis of an accidental behavior of nuclear fuel as well as normal behavior. The result will be used as basic data for the robust design of nuclear power plant and fuels. We extended the range of mechanical strain from small or medium to large adopting the Hencky logarithmic strain measure in addition to the Green-Lagrange strain and Almansi strain measures, for the possible large strain situation in accidental environments. We found that there is a critical heat generation after LOCA without ECCS (event category 5), under which the cladding of fuel sustains the internal pressure and temperature for the time being for the rescue of the power plant. With the heat generation above the critical value caused by malfunctioning of the control rods, the stiffness of cladding becomes zero due to the softening by high temperature. The weak position of cladding along the length continuously bulges radially to burst and to discharge radioactive substances. This kind of cases should be avoid by any means