859 research outputs found
TRANSIENT TEMPERATURE MEASUREMENTS OF COMBUSTOR WALLS ENCLOSING A 2-D MODEL COAXIAL INJECTOR
Direct measurements of combustor inner wall temperatures are difficult due to harsh flow conditions. A novel approach was used to obtain the combustor wall temperature as a function of time and location in a H2-O2 model injector, enclosing acoustically forced flames. The emphasis was to obtain thermal boundary conditions for various injector operation. The new approach combined a series of experimental measurements on the outer wall with a transient heat transfer analysis applicable for low Biot number and low Fourier number conditions. Infrared thermometry technique was applied to obtain outer wall temperature distribution at three different wall thicknesses, and these measurements were combined with the transient analysis to calibrate the amount of heat transfer and the corresponding inner wall temperature. The results showed that the combustor inner wall temperature distribution evolved much differently for acoustically forced flames, suggesting a different thermal boundary condition should be used in those cases
Characteristic Plain Radiographic and Intravenous Urographic Findings of Bladder Calculi Formed over a Hair Nidus: A Case Report
We present the characteristic plain radiographic and intravenous urographic (IVU) findings of calculus formed over a hair. A 66-year-old man who had been quadriplegic for 40 years because of vertebral injury was admitted for further evaluation of frequent urinary tract infection. Plain radiography showed a linear, serpiginous calcification in the lower abdomen, and IVU revealed a round filling defect with linear radiopacity in the bladder, suggesting calculus. The gross appearance of the stone after extraction demonstrated that calcification had formed over a hair
Comparison of longitudinal treatment effects with facemask and chincup therapy followed by fixed orthodontic treatment on Class III malocclusion
Objective: The purpose of this study was to compare the longitudinal treatment effects of facemask with
rapid maxillary expansion (FM/RME) and chincup (CC) therapy followed by fixed orthodontic treatment
(FOT) in Class III malocclusion (CIII) patients. Methods: The samples consisted of twenty-one CIII patients
who had similar skeletal and dental characteristics before FM/RME or CC therapy and good retention results
(Class I molar/canine relationship and positive overbite/overjet) after FOT (Group 1, FM/RME, n =
11; Group 2, CC, n = 10). Lateral cephalograms were taken before (T0) and after FM/RME or CC therapy
(T1), and after FOT and retention (T2). Skeletal and dental variables were measured. Mann-Whitney U-test
and Wilcoxon signed-rank test were used for statistical analysis. Results: During T0-T1, FM/RME therapy
induced forward movement of point A, and labioversion of the upper incisors. Both groups showed posterior
repositioning of the mandible. FM/RME resulted in increase of the vertical dimension; however, CC caused
an increase in articular angle and decrease in gonial angle. During T1-T2, both groups exhibited forward
growth of point A. Group 1 showed forward growth and counterclockwise rotation of the mandible and increase
of IMPA; however, Group 2, showed increase of ANS-Me/N-Me and decrease of overbite.
Conclusions: The key factor for successful FM/RME and CC therapy and good retention results might be
a harmonized forward growth of the maxilla that could keep pace with the growth and rotation of the
mandible
EFFECTS OF MO, CR, AND V ADDITIONS ON TENSILE AND CHARPY IMPACT PROPERTIES OF API X80 PIPELINE STEELS
In this study, four API X80 pipeline steels were fabricated by varying Mo, Cr, and V additions, and their microstructures and crystallographic orientations were analyzed to investigate the effects of their alloying compositions on tensile properties and Charpy impact properties. Because additions of Mo and V promoted the formation of fine acicular ferrite (AF) and granular bainite (GB) while prohibiting the formation of coarse GB, they increased the strength and upper-shelf energy (USE) and decreased the energy transition temperature (ETT). The addition of Cr promoted the formation of coarse GB and hard secondary phases, thereby leading to an increased effective grain size, ETT, and strength, and a decreased USE. The addition of V resulted in a higher strength, a higher USE, a smaller effective grain size, and a lower ETT, because it promoted the formation of fine and homogeneous of AF and GB. The steel that contains 0.3 wt pct Mo and 0.06 wt pct V without Cr had the highest USE and the lowest ETT, because its microstructure was composed of fine AF and GB while its maintained excellent tensile properties.X1126sciescopu
Minimum well separation for small groundwater heat pump (GWHP) systems in Korea: Preliminary analysis based on regional aquifer properties
Shallow geothermal energy has been estimated to have an excellent applicability in Korea, and its applications for space heating and cooling have steadily increased in recent years. Such application as ground source heat pump (GSHP) system can be classified into closed- and open-loop. In recent years, studies have been conducted to minimize the environmental impacts resulting from pumping/injection and to enhance the efficiency of groundwater heat pump (GWHP) system that is the open-loop system. These studies suggest that the characteristics of the aquifer have a significant role in designing efficient GWHP systems. This study considers various hydrogeological properties of Korea. An open-source numerical code called TRS was used for preliminary and sensitivity analyses of GWHP systems. In the analyses, arrival time when thermal plume arrives at pumping well and temperature change at pumping well were observed with different pumping/injection rates, hydraulic gradient, and well separation. Thus, we derived adequate well arrangement for efficient GWHP operation
Ultrasound of the Urinary Bladder, Revisited
Urine-filled bladder can be evaluated easily with ultrasound, and bladder tumors are usually well shown at ultrasound. Although ultrasound is not a primary imaging modality for staging of bladder tumors, it can provide general information regarding depth of tumor invasion into the proper muscle or perivesical adipose tissue. Ultrasound is also useful in showing nonneoplastic lesions of the bladder, such as stone, cystitis, diverticulum and ureterocele. Color Doppler ultrasound can show vascularity of the tumor. It also shows urine flow from the ureteral orifice or through the diverticular neck. As compared with transabdominal ultrasound, transrectal ultrasound shows bladder lesions more markedly in the dorsal wall or neck of the bladder
Arterial Injury Associated with Tension-Free Vaginal Tapes-SECUR Procedure Successfully Treated by Radiological Embolization
Various postoperative complications have been reported after the use of tension-free vaginal tapes (TVT). The transobturator approach was introduced to minimize the potential complications. The next generation of recently introduced TVT-SECUR is intended to minimize the incidence of complications. Herein we report a case of internal pudendal artery injury sustained during this procedure that was successfully treated by radiological embolization. Angiography with vessel embolization, when available, should be considered when the arterial injury is suspected
Classification of the glioma grading using radiomics analysis
Background Grading of gliomas is critical information related to prognosis and survival. We aimed to apply a radiomics approach using various machine learning classifiers to determine the glioma grading. Methods We considered 285 (high grade n = 210, low grade n = 75) cases obtained from the Brain Tumor Segmentation 2017 Challenge. Manual annotations of enhancing tumors, non-enhancing tumors, necrosis, and edema were provided by the database. Each case was multi-modal with T1-weighted, T1-contrast enhanced, T2-weighted, and FLAIR images. A five-fold cross validation was adopted to separate the training and test data. A total of 468 radiomics features were calculated for three types of regions of interest. The minimum redundancy maximum relevance algorithm was used to select features useful for classifying glioma grades in the training cohort. The selected features were used to build three classifier models of logistics, support vector machines, and random forest classifiers. The classification performance of the models was measured in the training cohort using accuracy, sensitivity, specificity, and area under the curve (AUC) of the receiver operating characteristic curve. The trained classifier models were applied to the test cohort. Results Five significant features were selected for the machine learning classifiers and the three classifiers showed an average AUC of 0.9400 for training cohorts and 0.9030 (logistic regression 0.9010, support vector machine 0.8866, and random forest 0.9213) for test cohorts. Discussion Glioma grading could be accurately determined using machine learning and feature selection techniques in conjunction with a radiomics approach. The results of our study might contribute to high-throughput computer aided diagnosis system for gliomas
Long-Term Clinical Outcomes of Sirolimus- Versus Paclitaxel-Eluting Stents for Patients With Unprotected Left Main Coronary Artery Disease Analysis of the MAIN-COMPARE (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty Versus Surgical Revascularization) Registry
ObjectivesThe aim of this study was to evaluate long-term clinical outcomes after implantation of sirolimus-eluting stents (SES) or paclitaxel-eluting stents (PES) among patients with unprotected left main coronary artery (LMCA) disease.BackgroundThere have been few comparisons of long-term outcomes among currently available drug-eluting stents (DES) for the treatment of LMCA disease.MethodsA total of 858 consecutive patients with unprotected LMCA stenosis were treated with SES (n = 669) or PES (n = 189) between May 2003 and June 2006. Primary outcome was the composite of death, myocardial infarction (MI), or target vessel revascularization (TVR).ResultsBaseline clinical and angiographic characteristics were similar in the 2 groups. During 3 years of follow-up, the adjusted risk of primary composite outcome was similar among the groups (SES vs. PES: 25.8% vs. 25.7%, hazard ratio [HR]: 0.95, 95% confidence interval [CI]: 0.64 to 1.41, p = 0.79). The 2 groups also showed a comparable adjusted rate of each component of outcome: death (9.1% vs. 11.0%, HR: 0.92, 95% CI: 0.47 to 1.80, p = 0.82), MI (8.1% vs. 8.0%, HR: 0.80, 95% CI: 0.43 to 1.48, p = 0.47), and TVR (12.1% vs. 10.6%, HR: 1.10, 95% CI: 0.53 to 2.29, p = 0.81). The 3-year rates of definite or probable stent thrombosis were 0.6% in the SES group and 1.6% in the PES group (adjusted p = 0.18).ConclusionsIn consecutive patients with unprotected LMCA disease undergoing DES implantation, SES and PES showed similar long-term clinical outcomes in terms of death, MI, repeat revascularization, and stent thrombosis
- …