======================================================================                   ENGINEERING NEWS IN BRIEF                         E-Mail Newsletter                                No.82              Issued by the Asian TOP Panel, October 2008            The Chinese Mechanical Engineering Society (CMES)            The Institution of Engineers, Indonesia (PII)            The Japan Society of Mechanical Engineers (JSME)            The Korean Society of Mechanical Engineers (KSME) ======================================================================     According to the agreement made in the 2nd Asian TOP Panel Meeting, the ENGINEERING NEWS IN BRIEF (E-mail newsletter) has now been edited by the JSME for the year 2008. ====================================================================== [Contents] 1)  Preparation of High Performance Optical Coatings with “Nano Particle Coating”     (Source: JSME) 2)  Active Compensation for Magnetic Noise (Source: JSME) 3)  Experimental Study on Biodiesel Engine Emissions Using Non-thermal Plasma     (Source: CMES) 4)  Elastohydrodynamics Lubrication Analysis of Misaligned Journal Bearing Considering      Surface Roughness (Source: CMES) 5)  Agreement of Cooperation Signed between SOE and CMES (Source: CMES) 6)  High-Accuracy Digital-Analog Actuators Using Load Springs Compensating      Fabrication Errors (Source: KSME) 7)  Structural Optimization of the Lower Parts in a Humanoid Considering Dynamic      Characteristics (Source: KSME) 8)  A study on Thermal Performance of Micro Channel Water Block for Computer CPU      Cooling (Source: KSME) ======================================================================== 1) Preparation of High Performance Optical Coatings with “Nano Particle     Coating”     Tsuyoshi Murata, Nicon Corporation An ultra-low refractive index is very advantageous when one designs antireflection coatings. We have successfully obtained high quality MgF2 coatings with ultra-low refractive indices by the sol-gel method.  These coatings are called "Nano Particle Coating" because the size of the particles that compose these coatings ranges from a few nanometers to just more than 10 nm.  The reflectance of the antireflection coating with 5 layers, of which the top layer is formed by our method, is lower than 0.6 % in the incident angle range of 0-60° at 193 nm.  The transmittance of CaF2 substrate with antireflection coatings made by our method is higher than 99 % in the range of 156-190 nm.  Moreover, the coatings made by our method have high laser exposure durability at 193 nm.  Now, the Nano Particle Coatings are used not only in projection lenses of optical lithography instrument for IC manufacturing, but are also in interchangeable camera lenses as a "Nano Crystal Coat". ======================================================================== 2) Active Compensation for Magnetic Noise     Amane Hayashi, Forestec Co., Ltd.  When measuring weak magnetic fields such as a biomagnetic measurement, it is necessary to reject the disturbing background fields. Hence, a magnetically shielded room (MSR) with multiple layers of permalloy is usually used to reduce environmental magnetic field noise. Unfortunately, the MSR is expensive and hardly transportable. However, for many applications, it is preferable to measure in an unshielded environment.  The techniques of magnetic shielding using active noise compensation (ANC) have proposed for biomagnetic measurements. This article was focused on the feedback ANC technique. A proposed method consisted of a noise detector, a compensation coil and an electronic circuit which was adjustment for the compensation current. The noise detector was used a 100-turn square coil with dimensions of 1m x 1m. The compensation coil was used a 30-turn square helmholtz coil with dimensions 1m x 1m. The output of the noise detector was amplified and optimized by the adjustment circuit. This adjustment circuit fed a current through the compensation coil.  As a result, the feedback ANC reduced low frequency magnetic noise of 0.1 ? 100 Hz by 5 ? 20 dB including urban magnetic noise and vibration noises. The field noise of the power-line was reduced by 30 dB. Furthermore, odd harmonic noises of power-line were reduced by 15 ? 20 dB ======================================================================== 3) Experimental Study on Biodiesel Engine Emissions Using Non-thermal     Plasma      Cai Yixi , Wang Pan , Wang Jun , Wang Jing ,Li Xiaohua,      Jiangsu University Based on the dielectric barrier discharge theory, the non-thermal plasma reactor was designed. The main components of the biodiesel sample were detected using gas chroma-tography-mass spectrometry. The bench test experiment was carried out, and the reduction of diesel engine harmful emissions with NTP operating on both biodiesel and No 0 diesel had been investigated. Scanning electronic microscope and X-ray energy spectrometer were used to detect the surface structure and chemical component of particular samples from the exhausts of diesel engine. Results show that the particular matter is decreased remarkably but NOx emissions change a little by NTP, the biodiesel can improve the performance of combustion and the particular matter from the oxygenated fuel has less component and small diameter. The results of elemental analysis reveals that NTP is unaffected by exhausts impurity such as sulfur, and is one promising technology for diesel engine emissions reduction. Key words: dielectric barrier discharge; non-thermal plasma (NTP); biodiesel; bench test ======================================================================== 4) Elastohydrodynamics Lubrication Analysis of Misaligned Journal Bearing     Considering Surface Roughness     Sun Jun, Wang Zhenhua, Gui Changlin, Liu Jianglin      Hefei University of Technology Average Reynolds equation was used to analyze bearing lubrication. The surface deformation of bearing was calculated by deformation-matrix method. The results show that the oil viscosity-pressure relationship has large effect on the lubrication characteristics of misaligned bearing, especially under condition of great misalignment angle. The surface roughness affects lubrication characteristics of misaligned bearing when eccentricity ratio and angle of journal misalignment are all large and not considering surface deformation of bearing. The directional parameter of surface has obvious effect on lubrication of misaligned bearing when ratio of least film thickness to surface roughness is small. The surface roughness and directional parameter of surface have little effect on lubrication of misaligned bearing when considering deformation of bearing surface. Although having little effect on lubrication of aligned bearing, the deformation of bearing surface has remarkable effect on lubrication of aligned bearing. The larger the eccentricity ratio, the greater the effect of the deformation of bearing surface has on lubrication of misaligned bearing. Key words: rough surface; viscosity-pressure relationship; surface deformation; journal misalignment; bearing ======================================================================== 5) Agreement of Cooperation Signed between SOE and CMES  On October 20, the SOE (Society of Operations Engineers, UK) delegation led by SOE President Mr. Walter Ian Talbot Ling visited CMES. The two sides held friendly talk and signed an agreement of reciprocal recognition on professional qualifications for engineers of both organizations.  Under this agreement, CMES Certified Mechanical Engineers and Certified Senior Mechanical Engineers will be eligible to apply for the qualification of SOE Incorporated Engineer (IEng) or SOE Chartered Engineer (CEng) approved by the Engineering Council of United Kingdom (ECUK). Similarly, SOE engineers are eligible to apply to be CMES engineers.  Both organizations hope to strengthen their collaboration in this regard with the aim to provide their members with more development opportunities and high quality service. ======================================================================== 6) High-Accuracy Digital-Analog Actuators Using Load Springs Compensating     Fabrication Errors     Won Han, Won Chul Lee, Young-Ho Cho       Korea Advanced Institute of Science and Technology  We present a high-accuracy digital-to-analog (DA) actuator using a load spring, specially designed to compensate the output displacement errors caused by fabrication errors. The compensated linear DA actuator is capable to change the slope of input-output modulation line in order to compensate fabrication errors. We design, fabricate, and characterize three different prototypes: one uncompensated design and two compensated designs respectively for a specific value and for a given range of fabrication error. The compensated linear DA actuators show the output displacement errors of -0.20±0.23? and -0.13±0.18?, respectively, reduced by 64.3% and 76.8% of the output displacement error, 0.56±0.20?, produced by the conventional uncompensated linear DA actuator. We experimentally verify the fabrication error compensation capability of the present compensated linear DA actuators, thus demonstrating high-accuracy actuation performance immune to fabrication errors. Key words: Digital-to-Analog Actuator, Fabrication Error Compensation, High-Accuracy Actuation ======================================================================== 7) Structural Optimization of the Lower Parts in a Humanoid Considering     Dynamic Characteristics Eul-Pyo Hong*, Il-Kwon Lee**, Bum-Jae You***, Chang-Hwan Kim***, Gyung-Jin Park* *: Han Yang University, **: Sam Sung Engineering Co., ***: KIST A humanoid is a robot with its overall appearance based on that of the human body. When the humanoid moves or walks, dynamic forces act on the body structure. Although the humanoid keeps the balance by using a precise control, the dynamic forces generate unexpected deformation or vibration and cause difficulties on the control. Generally, the structure of the humanoid is designed by the designer’s experience and intuition. Then the structure can be excessively heavy or fragile. A humanoid design scenario for a systematic design is proposed to reduce the weight of the structure while sufficient strength is kept. Lower parts of the humanoid are selected to apply the proposed design scenario. Multi-body dynamics is employed to calculate the external dynamic forces on the parts and structural optimization is carried out to design the lower parts. Because structural optimization using dynamic forces directly is fairly difficult, linear dynamic response structural optimization using equivalent static loads is utilized. Topology and shape optimizations are adopted for two steps of initial and detailed designs, respectively. Various commercial software systems are used for analysis and optimization. Improved designs are obtained and the design results are discussed. Key words: Humanoid, Structural Optimization, Equivalent Static Load, Multibody Dynamics ======================================================================== 8) A Study on Thermal Performance of Micro Channel Water Block for     Computer CPU Cooling      Oh-Kyung Kwon, Mi-Jin Choi, Dong-An Cha, Jae-Ho Yun      Korea Institute of Industrial Technology The object of this paper is to study on the thermal performance of a micro channel water block for computer CPU cooling. The effects of liquid flow rate, micro channel width and height on the thermal performances of water block are investigated experimentally. The water block was fabricated Al and machined with a micro milling. The water block consisted of rectangular micro channels 0.5 to 0.9�o width and 1.5 to 4.5 �o height. The experiments were conducted using deionized water, over a liquid flow rate ranging from 0.2 to 2.0 �s/min. The base temperature and thermal resistance decrease with increasing of liquid flow rate. The increase of a channel height is more effective on the thermal resistance than the decrease of a channel width. At the flow rate of 0.7 �s/min, input power of 100W, the base temperature and thermal resistance of sample 6 is 33℃ and 0.13 ℃/W respectively. Key Words: Base Temperature, Micro Channel, Pressure Drop, Thermal Resistance, Water Block ============================================================ Editor : International Affairs Committee Published by The Japan Society of Mechanical Engineers Shinanomachi-Rengakan Bldg, Shinanomachi 35, Shinjuku-ku, Tokyo 160-0016, Japan FAX : 81-3-5360-3508 All Rights Reserved, Copyright C 2008 The Japan Society of Mechanical Engineers URL:http//www.jsme.or.jp [English Version]

 

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