ICEF2004 -889 NUMERICAL PREDICTION ON THE CHARACTERISTICS OF SPRAY-INDUCED MIXING AND THERMAL DECOMPOSITION OF UREA SOLUTION IN SCR SYSTEM

ABSTRACT The spray-induced mixing characteristics and thermal decomposition of aqueous urea solution into ammonia have been studied to design optimum sizes and geometries of the mixing chamber in SCR (Selective Catalytic Reduction) system. The cold flow tests about the urea-injection nozzle were performed to clarify the parameters of spray mixing characteristics such as mean diameter and velocity of drops and spray width determined from the interactions between incoming air and injected drops. Discrete particle model in Fluent code was adopted to simulate spray-induced mixing process and the experimental results on the spray characteristics were used as input data of numerical calculations. The simulation results on the spray-induced mixing were verified by comparing the spray width extracted from the digital images with the simulated particle tracks of injected drops. The single kinetic model was adopted to predict thermal decomposition of urea solution into ammonia and solved simultaneously along with the verified spray model. The hot air generator was designed to match the flow rate and temperature of the exhaust gas of the real engines. The measured ammonia productions in the hot air generator were compared with the numerical predictions and the comparison results showed good agreements. Finally, we concluded that the design capabilities for sizing optimum mixing chamber were established

Geographical Distribution of Vi-Phage Types of Salmonella typhi Isolated in East Asia; A Review Made Mainly on a Basis of Results in Korea

Typhoid fever is now a minor cause of death, but it remains at fairly high rate in some area of Asiatic countries. In Korea it is on the increase since several years, and in Japan, to be scarce now, the case rate is stagnant since 1960. The Vi-phage typi

Electrophysiological Characterization of Benzofuroindole- Induced Potentiation of Large-Conductance Ca 2ϩ -Activated K ϩ Channels

ABSTRACT Large-conductance Ca 2ϩ -activated K ϩ (BK Ca ) channels are widely distributed and play key roles in various cell functions. We previously reported the chemical synthesis of several benzofuroindole compounds that act as potent openers of BK Ca channels. In this study, we investigated the mechanism of channel potentiation by one of the compounds, 7-trifluoromethyl-10H-benzo [4,5]furo[3,2-b]indole-1-carboxylic acid (TBIC), using electrophysiological means. This chemical highly activated cloned BK Ca channels from extracellular side independent of ␤ subunits and regardless of the presence of intracellular Ca 2ϩ . The EC 50 and Hill coefficient for rat BK Ca channel ␣ subunit, rSlo, were estimated as 8.9 Ϯ 1.5 M and 0.9, respectively. TBIC shifted the conductance-voltage curve of rSlo channels to more hyperpolarized potentials without altering its voltage dependence. Single-channel recording revealed that TBIC increased the open probability of the channel in a dosedependent manner without any changes in single-channel conductance. Strong potentiation by TBIC was also observed for native BK Ca channels from rat hippocampus pyramidal neurons. Thus, TBIC and the related benzofuroindole compounds can be useful tools to unravel the mechanism of this novel allosteric activation of BK Ca channels

A Small Dorsal Pontine Infarction Presenting with Total Gaze Palsy Including Vertical Saccades and Pursuit

A small localized infarction in the dorsal pontine area can cause various eye-movement disturbances, such as abducens palsy, horizontal conjugate gaze palsy, internuclear ophthalmoplegia, and one-and-a-half syndrome. However, complete loss of vertical saccades and pursuit with horizontal gaze palsy has not been reported previously in a patient with a small pontine lesion. We report a 67-year-old man with a small dorsal caudal pontine infarct who exhibited total horizontal gaze palsy as well as loss of vertical saccades and pursuit

Large Oncocytic Adrenocortical Tumor with Uncertain Malignant Potential

Oncocytoma is a neoplasm consisting of oncocytes that is found in the salivary gland, kidney, and thyroid. Adrenocortical oncocytoma is particularly uncommon, and most cases reported are benign and nonfunctioning. Here, we report a 20 cm adrenal mass associated with necrosis that was identified as an oncocytic adrenocortical tumor with uncertain malignant potential through histopathological evaluation after its resection

Bilateral iliac and popliteal arterial thrombosis in a child with focal segmental glomerulosclerosis

Thromboembolic complications (TECs) are clinically important sequelae of nephrotic syndrome (NS). The incidence of TECs in children is approximately 2%–5%. The veins are the most commonly affected sites, particularly the deep veins in the legs, the inferior vena cava, the superior vena cava, and the renal veins. Arterial thrombosis, which is less common, typically occurs in the cerebral, pulmonary, and femoral arteries, and is associated with the use of steroids and diuretics. Popliteal artery thrombosis in children has been described in cases of traumatic dissection, osteochondroma, Mycoplasma pneumoniae infection, and fibromuscular dysplasia. We report of a 33-month-old girl with bilateral iliac and popliteal arterial thrombosis associated with steroid-resistant NS due to focal segmental glomerulosclerosis. Her treatment involved thrombectomy and intravenous heparinization, followed by oral warfarin for 8 months. Herein, we report a rare case of spontaneous iliac and popliteal arterial thrombosis in a young child with NS

Are Portable Imaging Intraoperative Radiographs Helpful for Assessing Adequate Acetabular Cup Positioning in Total Hip Arthroplasty?

Despite advances in surgical techniques and instrumentation, current intra-operative estimations of acetabular version in total hip arthroplasty are of limited accuracy. In the present study, two experienced orthopedic surgeons compared intra-operatively measured (using portable imaging) anteversions and vertical inclinations of acetabular components with those measured using standardized radiographs post-operatively in 40 patients. Of the all vertical inclinations measured from intra-operative radiographs, 72.5% (n=29) were within ±2°, and 97.5% (n=39) were within ±5° of those determined using post-operative radiographs, and for anteversion, 52.5% (n=21) were within ±2°, and 97.5% (n=39) were within ±5°. Post-operative radiographs demonstrated that 90.0% (n=36) of vertical inclinations and anteversions were within the adequate zone. Obviously, our method has its limitations, but the authors conclude that the method described in this article better allows surgeons to verify acetabular version intra-operatively. In particular, the described method is suitable in cases with a deformed acetabular anatomy and difficult revision surgery