Performance of ceramic enhanced phenolic matrix brake lining materials for automotive brake linings

본 연구는 보육교사들의 영유아 건강관리 능력을 향상시킬 수 있는 교육프로그램을 개발하여 적용하고 그 효과를 측정하기 위함이다. 연구대상은 3개 도시, 400명의 보육교사들이며 영유아 건강관리 교육 전 후의 교육효과를 검정하기 위해 단일군 전후설계 유사실험연구로 실시되었다. 자료수집 기간은 2013년 9월초부터 10월말까지 이루어졌으며, 영유아 건강관리 교육의 내용은 영유아 건강관찰, 영유아 응급처치, 영유아 건강문제관리 세 영역으로 구성되었다. 교육은 주1회, 3시간씩 3주간 총 9시간으로 이루어졌다. 영유아 건강관리 교육을 실시한 후 보육교사들의 '영유아 건강관찰', '영유아 응급처치', '영유아 질병관리'에 있어서의 지식점수는 교육전보다 교육후에 유의미하게 높은 것으로 나타났으며, 이러한 결과는 보육교사를 위한 영유아 건강관리 교육 프로그램이 효과가 있었다고 해석된다. 그러므로 보육교사의 영유아 돌봄의 질을 향상시키기 위해 이와 같은 교육이 보수교육에 적용되기를 기대한다. 【This study aims to enhance child care teachers' ability to offer health care by developing an educational program for children's health care and safety. This study was carried out using a one-group pretest-posttest design based on a survey of 400 child care teachers in 3 cities. The educational program for child care teachers consisted of three parts: child health observations, disease management for child and emergency care for children. The educational program was conducted 3 times for 3 hours, totaling 9 hours. The educational program showed better grades of child care teachers in child health observation, emergency care for children, and disease management for children. The finding indicates that more child care teachers will adopt a health care education program to improve the quality of child care service.】

The Korea Academia-Industrial cooperation Society

Influence of convective cooling on a disc brake temperature distribution during repetitive braking

Ventilated disc brakes are widely used for reducing velocity due to their braking stability, controllability and ability to prove a wide-ranging brake torque. During braking, the kinetic energy and potential energies of a moving vehicle are converted into thermal energy through friction heating between the brake disc and the pads. The object of the present study is to investigate the temperature and thermal stress in the ventilated disc-pad brake during single brake. The brake disc is decelerated at the initial speed with constant acceleration, until the disc comes to a stop. The ventilated pad-disc brake assembly is built by a 3D model with a thermo-mechanical coupling boundary condition and multi-body model technique. To verify the simulation results, an experimental investigation is carried out.

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Investigation of temperature and thermal stress in ventilated disc brake based on 3D thermo-mechanical coupling model

Some falcons, such as peregrines (Falco peregrinus), attack their prey in the air at the end of high-speed dives and are thought to be the fastest of animals Estimates of their top speed in a dive range up to 157 m s-1, although speeds this high have never been accurately measured This study investigates the aerodynamic and gravitational forces on 'ideal falcons' and uses a mathematical model to calculate speed and acceleration during diving Ideal falcons have body masses of 05-20 kg and morphological and aerodynamic properties based on those measured for real falcons The top speeds reached during a dive depend on the mass of the bird and the angle and duration of the dive Given enough time, ideal falcons can reach top speeds of 89-112 m s-1 in a vertical dive, the higher speed for the heaviest bird, when the parasite drag coefficient has a value of 018 This value was measured for low-speed flight, and it could plausibly decline to 007 at high speeds Top speeds then would be 138-174 m s-1 An ideal falcon diving at angles between 15 and 90 degrees with a mass of 1 kg reaches 95 % of top speed after travelling approximately 1200 m The time and altitude loss to reach 95 % of top speed range from 38 s and 322 m at 15 degrees to 16 s and 1140 m at 90 degrees, respectively During pull out at top speed from a vertical dive, the 1 kg ideal falcon can generate a lift force 18 times its own weight by reducing its wing span, compared with a lift force of 17 times its weight at full wing span The falcon loses 60 m of altitude while pulling out of the dive, and lift and loss of altitude both decrease as the angle of the dive decreases The 1 kg falcon can slow down in a dive by increasing its parasite drag and the angle of attack of its wings Both lift and drag increase with angle of attack, but the falcon can cancel the increased lift by holding its wings in a cupped position so that part of the lift is directed laterally The increased drag of wings producing maximum lift is great enough to decelerate the falcon at -15 times the acceleration of gravity at a dive angle of 45 degrees and a speed of 41 m s-1 (05 times top speed) Real falcons can control their speeds in a dive by changing their drag and by choosing the length of the dive They would encounter both advantages and disadvantages by diving at the top speeds of ideal falcons, and whether they achieve those speeds remains to be investigated

Gliding flight: speed and acceleration of ideal falcons during diving and pull out.

The objectives of this third edition of an SAE classic title are to provide readers with the basic theoretical fundamentals and analytical tools necessary to design braking systems for passenger vehicles and trucks that comply with safety standards, minimize consumer complaints, and perform safely and efficiently before and while electronic brake controls become active. This book, written for students, engineers, forensic experts, and brake technicians, provides readers with theoretical knowledge of braking physics, and offers numerous illustrations and equations that make the information easy to understand and apply. New to this edition are expanded chapters on: • Thermal analysis of automotive brakes • Analysis of hydraulic brake systems • Single vehicle braking dynamics

Rudolf Limpert

Papers

Brake design and safety