851 research outputs found
Development of a Chaff Dispense Program for Target Tracking Radar Deception
This study aims to develop an appropriate chaff dispensing program to deceive the target tracking radar (TTR) effectively. Chaff is a countermeasure commonly used by fighter aircraft to deceive TTR. However, there has been a lack of methodology for calculating chaff dispense programs that take into account the specific characteristics of the fighter, chaff, and TTR. This study proposes a methodology that considers these variables to calculate chaff dispense programs and addresses this gap. The proposed method is demonstrated through TESS engagement, which shows its effectiveness in various engagement situations
Study on the effect of a cold environment on the quality of three video laryngoscopes: McGrath MAC, GlideScope Ranger, and Pentax Airway Scope
Objective Several environmental factors influence the prehospital use of video laryngoscopes (VLs). For example, fogging of the VL lens can occur in cold environments, and the low temperature can cause the VLs to malfunction. As relevant research on the effect of environment on VLs is lacking, we aimed to study the effect of a cold environment on three commonly used VLs. Methods McGrath MAC, Pentax Airway Scope (AWS), and GlideScope Ranger were exposed to temperatures of -5°C, -10°C, -20°C, and -25°C for 1 hour each and then applied to a manikin in a thermohydrostat room 5 times. Immediately after turning on the power and inserting the blade, the time until an appropriate glottic image appeared on the screen was measured. Results McGrath MAC was able to accomplish immediate intubation regardless of the temperature drop. However, GlideScope Ranger required an average of 4.9 seconds (-5°C to -20°C) and 10.1 seconds (-25°C) until appropriate images were obtained for intubation. AWS showed adequate image acquisition immediately after blade insertion despite slight fogging at -20°C, but at -25°C, images suitable for intubation did not appear on the screen for an average of 4.7 minutes. Conclusion All three devices appear to be usable without any limitations up to -20°C. However, GlideScope Ranger and AWS may not produce images immediately at temperatures below -25°C. Thus, medical practitioners performing VL in a cold environment should be aware of the characteristics of the VL devices in advance
Estimation of axial curvature of anterior sclera: correlation between axial length and anterior scleral curvature as affected by angle kappa
Background: Though the development and fitting of scleral contact lenses are expanding steadily, there is no simple method to provide scleral metrics for scleral contact lens fitting yet. The aim of this study was to establish formulae for estimation of the axial radius of curvature (ARC) of the anterior sclera using ocular biometric parameters that can be easily obtained with conventional devices. Methods: A semi-automated stitching method and a computational analysis tool for calculating ARC were developed by using the ImageJ and MATLAB software. The ARC of all the ocular surface points were analyzed from the composite horizontal cross-sectional images of the right eyes of 24 volunteers; these measurements were obtained using anterior segment optical coherence tomography for a previous study (AS-OCT; Visante). Ocular biometric parameters were obtained from the same volunteers with slit-scanning topography and partial coherence interferometry. Correlation analysis was performed between the ARC at 8 mm to the axis line (ARC[8]) and other ocular parameters (including age). With ARC obtained on several nasal and temporal points (7.0, 7.5, 8.0, 8.5, and 9.0 mm from the axis line), univariate and multivariate linear regression analyses were performed to develop a model for estimating ARC with the help of ocular biometric parameters. Results: Axial length, spherical equivalent, and angle kappa showed correlations with temporal ARC[8] (tARC[8]; Pearson’s r = 0.653, −0.579, and −0.341; P = 0.001, 0.015, and 0.015, respectively). White-to-white corneal diameter (WTW) and anterior chamber depth (ACD) showed correlation with nasal ARC[8] (nARC[8]; Pearson’s r = −0.492 and −0.461; P = 0.015 and 0.023, respectively). The formulae for estimating scleral curvatures (tARC, nARC, and average ARC) were developed as a function of axial length, ACD, WTW, and distance from the axis line, with good determinant power (72 − 80 %; SPSS ver. 22.0). Angle kappa showed strong correlation with axial length (Pearson’s r = −0.813, P <0.001), and the different correlation patterns of nasal and temporal ARC with axial length can be explained by the ocular surface deviation represented by angle kappa. Conclusions: Axial length, ACD, and WTW are useful parameters for estimating the ARC of the anterior sclera, which is important for the haptic design of scleral contact lenses. Angle kappa affects the discrepancies between the nasal and temporal scleral curvature.Korea (South). Ministry of Health & Welfare (Projects A084496 and A120018
Regulatory gaps between LNG carriers and LNG fuelled ships
Given a number of marine vessels treating the liquefied natural gas either as cargo or fuel, this paper examined the regulatory gaps of two different international Codes – the InternationalCodeof the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk and the International Code of Safety for Ships Using Gases or Other Low-flashpoint Fuels – from the regulatory standpoint. Results of the gap analysis have identified and discussed the key areas encountered with regulatory discrepancies or ambiguities that might interrupt the proper design, construction and operation of LNG carrier and LNG fuelled ship. A systematic investigation and harmonisation process across the Codes was proposed to mitigate the potential issues that may arise from the discordant regulations. Also, the International Maritime Organization was suggested to take proactive action to improve such dissonances while a general insight into the importance of filling those gaps was provided for rule-makers and stakeholders
Clinical Efficacy of Near-Infrared Reflectance Imaging and Optical Coherence Tomography in Identifying Ocular Manifestations of Neurofibromatosis Type 1 in Korean Children
Purpose The aim of this study was to investigate the clinical efficacy of near-infrared reflectance (NIR) imaging and optical coherence tomography (OCT) in identifying ocular manifestations of neurofibromatosis type 1 (NF1) in Korean children. Methods This retrospective chart review study included five Korean children with NF1 aged under 18 years who had undergone ophthalmic procedures, including slit-lamp examinations, NIR imaging, and OCT scanning. Results Multiple patchy bright lesions were observed on NIR imaging in all eyes (10 eyes in five patients). Further NIR imaging and OCT scans showed that these lesions, confined to the choroid, were choroidal nodules. Lisch nodules, contrastingly, were found in only four of 10 eyes by slit-lamp examinations on the same day as the NIR imaging. One of those four eyes had only one Lisch nodule, which did not meet the NF1 diagnostic criteria. Conclusion NIR imaging enabled the detection of choroidal nodules in Korean children with NF1. Moreover, for Korean children with NF1, choroidal nodules were earlier-detected ocular manifestations relative to Lisch nodules. NIR imaging, along with OCT, is a useful protocol for localizing NF1 nodules in children
Environmental considerations of plastic behaviors for automobile applications
AbstractIt is well known fact that the thermo-mechanical behaviors of polymeric materials are strongly influenced by environmental factors, and, for automobiles, the mechanical properties of interior plastic structures are noticeably changed by being repeatedly exposed to environments such as sun light and rains. As the properties change, mechanical fits such as fasteners and clips in automobiles lose their tightness, creating unexpected noises. To consider Buzz, Squeak and Rattle (BSR) from initial stage of the interior design, it is very important to obtain, analyze and understand the structural behaviors of the materials under environmental changes as well as time. In this report, the mechanical property changes of the plastics for automobiles are measured to investigate the temperature and humidity effects. The samples are undergone different temperature and humidity conditions, and regularly taken out to measure the thermo-mechanical properties. The data are compared with the original samples, and analyzed for the properties change. Viscoelastic characteristics such as glass transition temperatures and storage/loss modulus were also investigate
Enhanced overall efficiency of GaInN-based light-emitting diodes with reduced efficiency droop by Al-composition-graded AlGaN/GaN superlattice electron blocking layer
AlxGa1-xN/GaN superlattice electron blocking layers (EBLs) with gradually decreasing Al composition toward the p-type GaN layer are introduced to GaInN-based high-power light-emitting diodes (LEDs). GaInN/GaN multiple quantum well LEDs with 5- and 9-period Al-composition-graded AlxGa1-xN/GaN EBL show comparable operating voltage, higher efficiency as well as less efficiency droop than LEDs having conventional bulk AlGaN EBL, which is attributed to the superlattice doping effect, enhanced hole injection into the active region, and reduced potential drop in the EBL by grading Al compositions. Simulation results reveal a reduction in electron leakage for the superlattice EBL, in agreement with experimental results. (C) 2013 AIP Publishing LLC.open1133sciescopu
Development of a Chaff Dispense Program for Target Tracking Radar Deception
This study aims to develop an appropriate chaff dispensing program to deceive the target tracking radar (TTR) effectively. Chaff is a countermeasure commonly used by fighter aircraft to deceive TTR. However, there has been a lack of methodology for calculating chaff dispense programs that take into account the specific characteristics of the fighter, chaff, and TTR. This study proposes a methodology that considers these variables to calculate chaff dispense programs and addresses this gap. The proposed method is demonstrated through TESS engagement, which shows its effectiveness in various engagement situations
The Influence of Preoperative Bladder Outlet Obstruction on Continence and Satisfaction in Patients with Stress Urinary Incontinence after Midurethral Sling
Purpose We studied the influence of preoperative bladder outlet obstruction (BOO) on postoperative continence rates and patient satisfaction after the midurethral sling procedure. Methods A total of 159 women who underwent the midurethral sling procedure were evaluated. Using the Blaivas-Groutz nomogram, we assigned the patients were assigned to Group I (n=37, no obstruction), Group II (n=89, mild obstruction), or Group III (n=33, moderate to severe obstruction). Continence rates, patient satisfaction, urinary sensation scale and uroflowmetry were evaluated postoperatively. Results There were no significant differences in continence rates, satisfaction, or postoperative maximal flow rate between the 3 groups. Postoperative urgency was improved after surgery in Groups I and II (P<0.05) but not in Group III. Conclusions BOO does not seem to be a risk factor for failure after the midurethral sling procedure. However, BOO may be considered as a potential factor for persistent storage symptoms after the midurethral sling
- …