Valve Location Method for Evaluating Drain Efficiency in Water Transmission Pipelines

Water transmission pipelines, which transport bulk water into storage facilities, usually have a tree-type configuration with large dimensions; thus, the breakage of a pipeline may cause a catastrophic service interruption to customers. Although drain efficiency is closely related to the number of washout and control valves and their locations, there is no useful guideline. This paper proposes a valve locating method by introducing numerical analyses to enumerate drainage time and zone. A time integration method, combined with the Newton–Raphson algorithm, is suggested to resolve drainage time, while considering the friction loss in gravitational flow. A drain direction matrix, which shows drain direction and coverage, is derived using a network searching algorithm. Furthermore, a feasible practical approach is presented by introducing a critical horizontal slope, a major washout valve, drainage indices, and control valve embedment. The developed method is first applied to simple pipes to validate the drainage time module. Subsequently, the model is expanded to the CY transmission line, which is one of the BR water supply systems in South Korea currently in operation. The results reveal that three drain valve locations have been neglected, and the addition of control valves guarantees consistent drain time below the operational criteria. Document type: Articl

Fabrication of Nonenzymatic Glucose Sensors Based on Multiwalled Carbon Nanotubes with Bimetallic Pt-M (M = Ru and Sn) Catalysts by Radiolytic Deposition

Nonenzymatic glucose sensors employing multiwalled carbon nanotubes (MWNTs) with highly dispersed Pt-M (M = Ru and Sn) nanoparticles (Pt-M@PVP-MWNTs) were fabricated by radiolytic deposition. The Pt-M nanoparticles on the MWNTs were characterized by transmittance electron microscopy, elemental analysis, and X-ray diffraction. They were found to be well dispersed and to exhibit alloy properties on the MWNT support. Electrochemical testing showed that these nonenzymatic sensors had larger currents (mA) than that of a bare glassy carbon (GC) electrode and one modified with MWNTs. The sensitivity (A mM−1), linear range (mM), and detection limit (mM) (S/N = 3) of the glucose sensor with the Pt-Ru catalyst in NaOH electrolyte were determined as 18.0, 1.0–2.5, 0.7, respectively. The corresponding data of the sensor with Pt-Sn catalyst were 889.0, 1.00–3.00, and 0.3, respectively. In addition, these non-enzymatic sensors can effectively avoid interference arising from the oxidation of the common interfering species ascorbic acid and uric acid in NaOH electrolyte. The experimental results show that such sensors can be applied in the detection of glucose in commercial red wine samples

New Signature Scheme Using Conjugacy Problem

We propose a new digital signature scheme based on a non-commutative group where the conjugacy search problem is hard and the conjugacy decision problem is feasible. We implement our signature scheme in the braid groups and prove that an existential forgery of the implementation under no message attack gives a solution to a variation of conjugacy search problem. Then we discuss performance of our scheme under suggested parameters

Electrocatalytic Activity for CO, MeOH, and EtOH Oxidation on the Surface of Pt-Ru Nanoparticles Supported by Metal Oxide

This paper describes the electrocatalytic activity for CO, MeOH, and EtOH oxidation on the surface of Pt-Ru nanoparticles supported by metal oxide (Nb-TiO2-H) prepared for use in a fuel cell. To prepare Nb-TiO2-supported Pt-Ru nanoparticles, first, the Nb-TiO2 supports were prepared by sol-gel reaction of titanium tetraisopropoxide with a small amount of the niobium ethoxide in polystyrene (PS) colloids. Second, Pt-Ru nanoparticles were then deposited by chemical reduction of the Pt4+ and Ru3+ ions onto Nb-TiO2 supports (Pt-Ru@Nb-TiO2-CS). Nb element was used to reduce electrical resistance to facilitate electron transport during the electrochemical reactions on a fuel cell electrode. Finally, the Pt-Ru@Nb-TiO2-H catalysts were formed by the removal of core-polystyrene ball from Pt-Ru@TiO2-CS at 500∘C. The successfully prepared Pt-Ru electrocatalysts were confirmed via TEM, XPS, and ICP analysis. The electrocatalytic efficiency of Pt-Ru nanoparticles was evaluated via CO, MeOH, and EtOH oxidation for use in a direct methanol fuel cell (DMFC). As a result, the Pt-Ru@Nb-TiO2-H electrodes showed high electrocatalytic activity for the electrooxidation of CO, MeOH, and EtOH

Palliative radiotherapy in patients with a symptomatic pelvic mass of metastatic colorectal cancer

<p>Abstract</p> <p>Background</p> <p>To evaluate the palliative role of radiotherapy (RT) and define the effectiveness of chemotherapy combined with palliative RT (CCRT) in patients with a symptomatic pelvic mass of metastatic colorectal cancer.</p> <p>Methods</p> <p>From August 1995 to December 2007, 80 patients with a symptomatic pelvic mass of metastatic colorectal cancer were treated with palliative RT at Samsung Medical Center. Initial presenting symptoms were pain (68 cases), bleeding (18 cases), and obstruction (nine cases). The pelvic mass originated from rectal cancer in 58 patients (73%) and from colon cancer in 22 patients (27%). Initially 72 patients (90%) were treated with surgery, including 64 complete local excisions; 77% in colon cancer and 81% in rectal cancer. The total RT dose ranged 8-60 Gy (median: 36 Gy) with 1.8-8 Gy per fraction. When the <b>α/β </b>for the tumor was assumed to be 10 Gy for the biologically equivalent dose (BED), the median RT dose was 46.8 Gy₁₀(14.4-78). Twenty one patients (26%) were treated with CCRT. Symptom palliation was assessed one month after the completion of RT.</p> <p>Results</p> <p>Symptom palliation was achieved in 80% of the cases. During the median follow-up period of five months (1-44 months), 45% of the cases experienced reappearance of symptoms; the median symptom control duration was five months. Median survival after RT was six months. On univariate analysis, the only significant prognostic factor for symptom control duration was BED ≥40 Gy₁₀(p < 0.05), and CCRT was a marginally significant factor (p = 0.0644). On multivariate analysis, BED and CCRT were significant prognostic factors for symptom control duration (p < 0.05).</p> <p>Conclusions</p> <p>RT was an effective palliation method in patients with a symptomatic pelvic mass of metastatic colorectal cancer. For improvement of symptom control rate and duration, a BED ≥ 40 Gy₁₀is recommended when possible. Considering the low morbidity and improved symptom palliation, CCRT might be considered in patients with good performance status.</p

Measurement of 129 I Radioactivity in Groundwater of Radioactive Waste Disposal Site

The investigation of the environmental radioactivity around the radioactive waste disposal site in Gyeongju is being carried out. The radioactivity of 129 I in groundwater and seaweed are to be measured. The analytical method to measure the radioactivity of 129 I in aqueous media was established. This method contains oxidation-reduction reaction, anion-exchange separation and palladium precipitation. The 129 I radioactivity in the PdI 2 precipitates was measured by using low-energy gamma spectrometer. The counts of peak at 39.6 keV of gamma energy were used for determination of 129 I radioactivity. The chemical recovery was determined by the weights of PdI 2 precipitates. The deionized water and groundwater spiked with 129 I tracer were tested. In the case of deionized water, the relative deviations of measured concentration from spiked one are from 1.1 to 10.7%. The relative deviations of measured radioactivity from spiked one in the groundwater experiments are 2.9 and 3.7%. The measured concentration is in good agreement with spiked one. The groundwater sampled from radioactive waste disposal site was tested. The concentrations of 129 I in the groundwater are below minimum detectable activities of 36.7 and 36.6 mBq/L