ENGINEERING NEWS IN BRIEF

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                  ENGINEERING NEWS IN BRIEF
                        E-Mail Newsletter

                               No.62
             Issued by the Asian TOP Panel, February 2007

           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)

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    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 CMES for the year 2007.

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[Contents]

(1) Effect of Ground Layer on Ultra Long Life Fatigue Behaviour in High Carbon
   Chromium Bearing Steel (Source: CMES)
(2) Design Of High Resolving Capability Stm.Ipc-205bj Type Atomic Force Microscope      (Source: CMES)
(3) Fuel Properties And Emission Characteristics Of Diesohol (Source: CMES)
(4) Gain-scheduled Control of a Smart Structure with Identification of a Crack
     (Source: JSME)
(5) A New Surface Modification Technique for Biomaterials (Source: JSME)
(6) Fabrication of Nickel Nano and Microstructures by Redeposition Phenomena in
     Ion Etching Process (Source: KSME)
(7) Theoretical Analysis and Experimental Characterization of DoD Metal-Jet System      (Source: KSME)
(8) An Experimental Investigation of Jet Impingement Cooling Using the Vortex Tube      (Source: KSME)

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(1) Effect of Ground Layer on Ultra Long Life Fatigue Behaviour in High Carbon      Chromium Bearing Steel

     LU Liantao Southwest Jiaotong University
     SHIOZAWA Kazuaki NISHINO Seiichi Faculty of Engineering,
     Toyama University, Toyama

In order to investigate the effect of ground layer on fatigue behavior of high carbon chromium bearing steel JIS SUJ2 in ultra-long life regime, rotating-bending fatigue tests are performed in laboratory air at room temperature using hour- glass-shaped emerized and electro-polished specimens. The emerized specimen and the electro-polished one are obtained by removing a partial ground layer with surface roughness and the whole ground layer from ground ones, respectively. The results show that S-N curves are composed of surface fracture mode curve in the region of short life and internal fracture mode curve in the region of long life. The S-N curves for surface fracture mode are affected by surface roughness and compressive residual stress. The S-N curves for internal fracture mode are not affected by surface conditions, which is an inherent characteristic of the material. For the surface fracture mode, the emerized specimen shows the largest fatigue limit, about 1.11 times larger than for the electro-polished one and 1.20 times larger than for the ground one. The fatigue limits of surface fracture mode affected by the surface compressive residual stress can be expressed by modified Goodman diagram. Fur- thermore, conditions for internal crack initiation and pro- pagation are discussed. The fatigue limit in ultra-long life regime is estimated.

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(2) Design Of High Resolving Capability Stm.Ipc-205bj Type Atomic Force Microscope

     PENG Guanghan College of Automation, Chongqing University
     YANG Xueheng XIN Hongzheng College of Mathematics and Science,
     Chongqing University

Based on a high resolving capability scanning tunneling microscope and development on hardware and software design, a new-style higher resolving capability and more useful AFM is developed. The principles of operation, components and some applications of the AFM system is resported. And the special design of the lens body and control process and the manufacture and work process of cantilever are introduced in detail. The AFM adopted a new simple and useful cantilever. This model uses an STM to detect the shift of the cantilever and uses four motors and two PZT tubes to enlarge the scanning rage and to enhance the resolution effectively. The AFM's resolving capability is as follows: transverse: 0.1 nm, vertical: 0.01 nm. Several images given as samples are obtained with the model.

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(3) Fuel Properties And Emission Characteristics Of Diesohol

     XU Boyan School of Mechanical Engineering, ShandongInstitute of Architecture
     and Engineering,
     ZHANG Weibin Jinan Railway Institute of Technology,
     CAI Shaoli School of Mechanical Engineering, Jinan University

An additive compound consisting of medium carbon alcohol, low carbon ether, macromolecule polymer and organic nitric acid ester is developed to overcome the problems of phase separation and low cetane number in the application of diesohol. The titration experiments prove that the mutual solubility between the diesel and the ethanol is improved by adding 1%～2% (in volume) of this additive. The engine bench tests show that the cold starting performance of the diesohol with the additive can be almost as good as that of the pure diesel. The effects which the pure diesel and several kinds of diesohol with different ethanol blend ratios have on the fuel economy, soot and the emissions of THC, CO and NOx are also investigated. As a result, the specific fuel consumption of each diesohol is more than that of diesel, but the brake thermal efficiency and the soot intensity are all better than those of diesel. The NOx emission deteriorates with the increasing of engine load but has a decline trend under high load operation conditions with the increasing of ethanol blend ratio.

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(4) Gain-scheduled Control of a Smart Structure with Identification of a Crack

    Kiyoshi TAKAGI, National Institute of Advanced Industrial
    Science and Technology (AIST)

This article deals with damage detection and vibration control of a smart structure.
A method for the crack identification when the vibration of the beam is suppressed by using active control is described in the first half of the article. A finite element model of a cracked beam is established. The natural frequencies are determined for a different crack length and locations. Furthermore, we design the gain-scheduled controller considering both the crack length and the location. The efficiencies of our crack identification method and the gain-scheduled controller design are verified by simulation and experiment. Damage detection and vibration control of a new smart board designed by mounting piezoelectric fibers with metal cores on the surface of a CFRP composite in the latter half of this article. If the fiber length is shortened due to a break, there is a decrease not only in actuator performance but also in the sensor output. Damage detection is based on the computed relation between the input/output signals and the damage position. The gain-scheduled controller is designed using LFT representation. Experimental results show that our gain-scheduled controller can improve control performance when damage causes a break in the piezoelectric fiber.

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(5) A New Surface Modification Technique for Biomaterials

     Masayosi MIZUTANI, Keio University
     Kazutoshi KATAHIRA, Riken

Biomaterials require certain desirable properties, which include high corrosion, wear and fatigue properties. Especially, in the case of very small bio-component, such as medical micro-machine, it is very difficult to apply the conventional surface modification process. Therefore, it is important to develop a new surface modification process for biomaterials.
In order to fabricate high quality surface with higher corrosion resistance, higher
mechanical properties and good biocompatibility, a new surface modification technique for biomaterials was developed by applying the conventional ELID (Electrolytic In-process Dressing) grinding. This developed technique inhibits a pitting of the surface and prevents dissolution of metal-ions because of formation of the thick oxide layer on the finished surface.
This suggests that this new technique may be used to fabricate machined surfaces with desirable characteristics for biomaterials. Furthermore, since this technique improves surface properties, it may be applicable not only to the machining of biomaterials, but also to the machining of micro-tools which are difficult to modify.

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(6) Fabrication of Nickel Nano and Microstructures by Redeposition Phenomena in
     Ion Etching Process

     Phill Gu Jung, Sung Jin Hwang, Sang Min Lee, Jong Soo Ko
     Pusan University

Nickel nano and microstructures are fabricated with simple process. The fabrication process consists of nickel deposition, lithography, nickel ion etching and plasma ashing. Well-aligned nickel nanowalls and nickel self-encapsulated microchannels were fabricated. We found that the ion etching condition as a key fabrication process of nickel nanowalls and self-encapsulated microchannels, i.e., 40 sccm Ar flow, 550 W RF power, 15 mTorr working pressure, and 20℃ water cooled platen without using He backside cooling unit and with using it, respectively. We present the experimental results and discuss the formational conditions and the effect of nickel redeposition on the fabrication of nickel nano and microstructures.

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(7) Theoretical Analysis and Experimental Characterization of DoD Metal-Jet System

     Taik-Min Lee, Tae Goo Kang, Jeong-Soon Yang, Jeong-Dai Jo,
     Kwang-Young Kim, Byung-Oh Choi, Dong-Soo Kim
     KIMM(Korea Institute of Machinery and Materials)

In this study, we present a design, analysis, fabrication and performance test of the novel DoD metal-jet system for application to the high-density and high-temperature-melting materials. The theoretical analysis of the metal-jet nozzle system is derived by using electro-mechanical analogy. Based on the theoretical analysis results, we design the metal-jet print head system and fabricate the metal-jet system, which can eject the droplet of lead-free metal solder in high-temperature. In the experimental test, we set up the test apparatus for visualization of the droplet ejection and measure the ejected droplet volume and velocity. As a result, the diameter, volume and the velocity of the ejected droplet are about 65 ~ 70,
145pl ~ 180 pl and 4, which shows quite good agreement with the theoretical analysis results of the 75?-diameter and 220 pl-volume of droplet. In comparison with the experimental result, the errors of diameter and volume are 7% ~ 13% and 18 ~ 34%, respectively.

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(8) An Experimental Investigation of Jet Impingement Cooling Using the Vortex Tube

     Woon-Chul Shin, Chang-Soo Kim, Shin-Chul Bae
     Dankook University

The jet impingement cooling characteristics are investigated experimentally. The study is motivated by the potential application of local hot spot cooling by means of the vortex tube. The purposes of this research are to examine the effect of the nozzle-block spacing and flow rate. The results of jet through vortex tube is compared with ones of circular jet. Flow visualization by the smoke-wire technique is also performed to investigate the flow structure. As the nozzle-block spacing is increased and flow rate decreased, the cooling effect of the jet through the vortex tube decreases mere remarkably than that of the circular jet. So the cooling effect for the jet through the vortex tube is higher than that for the circular jet at H/D3, Q10/h.

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Editor : Tian Ruizhu
           The Dept. of Internationa Affairs
           Chinese Mechanical Engineering Society