• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.397-401
• /
• 2003

In this work, diamond turning process is used to produce mirror surface on a Al cone. The Al cone as used as a mirror which can reflect a laser beam without scattering and, hence, it is critical to minimize the surface roughness of a Al cone. During diamond turning, feedrate and tool nose radius are changed to investigate characteristics of the ultra precision machined surface of a Al cone. A laser beam of 633 nm is applied to examine the effect of surface roughness on the characteristics of reflectivity. It is found that surface roughness is not significantly affected by feedrate. The main factor influencing surface roughness is tool nose radius. The line patterns of reflected laser beams show that the minimum surface roughness of 0.08 $\mu\textrm{m}$ (Ra) is required to avoid scattering phenomena of reflectivity.

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2534-2539
• /
• 2007

Launch vehicles are exposed to aerodynamic heating conditions while flying at high Mach numbers in the atmosphere. In this study aerodynamic heating test for fairing nose-cone was done using ATSF(Aerodynamic Thermal Simulation Facility) and Engineering Model for fairing. ATSF is a facility that can simulate given temperature profile using about 4,000 halogen heaters on fairing model. Aerodynamic heating profile is got from result of thermal analysis using MINIVER, Thermal Desktop and SINDA/FLUINT. After aerodynamic heat test, it is found that initial temperature of fairing inner surface and thickness of BMS has important effects on temperature of fairing inner surface. Also it is confirmed that maximum temperature of fairing nose-cone inner surface during flight is lower than allowable temperature limit. Later, thermal correlation between thermal analysis and experimental results will be done using aerodynamic heating test result

• Journal of dental hygiene science
• /
• v.24 no.3
• /
• pp.146-151
• /
• 2024

Background: Research is continuously being conducted on the relationship between the airway and malocclusion. The nose, as the upper part of the respiratory pathway, plays a critical role. While various international studies employ the Nasal Index classification for nasal morphology, domestic research remains scarce. This research investigates the proportions of nasal morphology in malocclusion patients utilizing a 3D software. Methods: The study evaluated 100 malocclusion patients in their 20s (40 Class I, 34 Class II, 26 Class III). Cone-beam computed tomography was used with the Mimics (ver. 22; Materialise) 3D program to model the skull and soft tissues of the patients in three views: coronal, sagittal, and frontal. Results: The results showed that in Class I, there were 5 leptorrhine (long and narrow) cases, 30 mesorrhine (moderate shape) cases, and 5 platyrrhine (broad and short) cases. In Class II, there were 3 leptorrhine, 25 mesorrhine, and 6 platyrrhine cases. In Class III, there were 2 leptorrhine, 21 mesorrhine, and 3 platyrrhine cases. Conclusion: The findings of this study indicate that there is no significant correlation between the size of the nose and malocclusion in patients. Additionally, additional research related to this study is expected to be necessary.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.30 no.6
• /
• pp.14-20
• /
• 2002

The aerodynamic heating at a nose cone is predicted under the KSR-III flight conditions. An equilibrium reacting gas condition is applied. The parametric study is performed with Mach number of 4.9, 10.2 and 15 and for the following nose shapes of hemisphere, cut cylinder and parabola. AUSMPW+ and shock aligned grid technique are used to provide the best aerodynamic solutions. In addition, the composite material of a nose cone is discussed in the viewpoint of a thermal safety.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.1
• /
• pp.23-32
• /
• 2016

Various studies have been conducted for drag reduction of a high-speed vehicle by injecting counterflow jet from its nose cone. In this study, in order to obtain baseline data and key parameters for drag reduction method, the counterflow jet study of the USA is reviewed and summarized. The nose cone shapes of each study are hemisphere cylinder, truncated cone, and reentry capsule, and their test conditions are summarized accordingly. Key parameters for drag reduction are jet mach number, mass flow rate, and pressure ratio. Even though drag reduction effects show various results according to given test conditions, it is found that the drag reduction effect reaches up to 40~50%.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.21 no.3
• /
• pp.49-55
• /
• 2017

In this study, gas turbine engine inlet duct was designed to satisfy uniform flow at aerodynamic interface plane (AIP). Haack-series was selected as nose cone profile and duct outer radius($r_o$) was designed to satisfy to match with area change rate between the nose cone and outer duct wall by the 1-D sizing. The design object of the inlet duct wall profile which has the gradual area change rate was uniform Mach number in the core flow region and minimum boundary later thickness at the both inner nose wall and outer duct wall. The flow characteristics inside the inlet duct was evaluated using CFD. The static pressure distribution at the AIP showed uniform pattern within 0.16%. Based on Mach number profile, the boundary layer thickness was 2% of channel height. Kiel temperature rake location was decided less than 100 mm in front of nose cone where the Mach number is less than 0.1 in order to maximize the temperature probe recovery rate.

• Journal of dental hygiene science
• /
• v.23 no.3
• /
• pp.193-198
• /
• 2023

Background: The nose is located at the center of the face, and it is possible to determine race, sex, and the like. Research using the nasal index (NI) classification method to classify the shape of the nose is currently in progress. However, domestic research is required as most research is being conducted abroad. In this study, we used a 3D program to confirm the ratio of the nose shape of Koreans. Methods: One hundred patients (50 males and 50 females) in their 20s were evaluated (IRB approval no. DKUDH IRB 2020-01-007). Cone beam computed tomography was performed using the Mimics ver.22 (Materialise Co., Leuven, Belgium) 3D program to model the patient's skull and soft tissues into three views: coronal, sagittal, and frontal. To confirm the ratio of measurement metrics, analysis was performed using the SPSS ver. 23.0 (IBM Co., Armonk, NY, USA) program. Results: Ten leptorrhine (long and narrow) type, 76 mesorrhine (moderate shape) type, and 14 platyrrhine (broad and short) type noses were observed. In addition, as a result of sex comparison, five males had the leptorrhine (long and narrow) type, 40 mesorrhine (moderate shape), and five platyrrhine (broad and short) types. For females, five patients had the leptorrhine (long and narrow) type, 36 patients had the mesorrhine (moderate shape) type, and nine patients had the platyrrhine (broad and short) type. Conclusion: This study will be helpful when performing nose-related surgeries and procedures in clinical practice and for similar studies in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.3
• /
• pp.308-313
• /
• 2006

The extent of impact dispersion is a function of parameters including gun geometry and tolerances, the foe control system, projectile manufacturing tolerances, etc. The study here investigates potential impact point accuracy improvement for a projectile realized by replacing the rigid nose cone wind screen with a passive nose. Toward this end, a nose projectile dynamic model is derived which consists of the standard six degrees of freedom similar to a rigid projectile plus three additional degrees of freedom associated with rotation of the nose with respect to the main projectile body. By Observing the pitch and yaw movement of the nose in the simulation results, it is believed to be possible to reduce the effects of uncertainties which is occurred at firing step.

• 한국전산유체공학회:학술대회논문집
• /
• 2004.10a
• /
• pp.197-201
• /
• 2004

A design optimization of Sphere-Cone blunt nose hypersonic flight vehicle has been studied by using upwind Navier-Stokes method and numerical optimization method. Heat transfer coefficient and drag coefficient are selected as objective function or design constraint. Control points of Bezier curve are considered as design variable.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.11
• /
• pp.903-910
• /
• 2020

This paper introduces a simulator to assess the impacts of the wind and the airframe vibration on the performance of the Active Electronically Scanned Array (AESA) radar mounted in an aircraft. The AESA radar is mounted on the nose cone of an aircraft, and vibration occurs due to the drag force. This vibration affects the behavior of the AESA radar and can cause phase errors in signal. The simulator adopts the geometric model for nose cone, the mathematical models on the rigid-body dynamics of the aircraft, the average/turbulent winds, and the mode/ambient vibrations to compute the position and the attitude of the radar accurately. Numerical studies reflecting a set of test scenarios were conducted to demonstrate the effectiveness of the developed simulator.