Wear Behaviors of UHMWPE against LTD-Free Zirconia/Alumina Composites

Lee, Myung Hyun,Seo, Won Seon,Kim, Hwan,Lee, Kwon Yong,Kim, Dae Joon,Lee, Deuk Yong Trans Tech Publications, Ltd. 2005 Key Engineering Materials Vol.284 No.-

<P>The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on four different compositions of novel low temperature degradation-free zirconia/alumina (Z/A) composite material used for a femoral head in total hip joint replacement. The wear of UHMWPE pins against these Z/A composite disks were evaluated by performing the linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in a bovine serum. The novel low temperature degradation (LTD)-free tetragonal zirconia polycrystal (TZP)/alumina composite (90(5.3Y, 4.6Nb)-TZP/10Al2O3) induced the less wear amount of UHMWPE than the other Z/A composites. Linear reciprocal motion wore more the UHMWPE pin than did repeat pass rotational motion for all disk materials. It was observed that few transfer film on the sliding track of Z/A composite disks and the matching contact surfaces of pins had relatively less scratch. Getting rid of transfer film, there is no change of surface roughness on the sliding track of Z/A composite disks. This novel Z/A composite (90(5.3Y, 4.6Nb)-TZP/10 Al2O3) demonstrates the potential as an alternative material for the femoral head in total hip replacement.</P>

Strength-Based and Wave-Based Liquefaction Characterization

Cho, Gye Chun,Lee, Jong Sub Trans Tech Publications, Ltd. 2006 Key Engineering Materials Vol.321 No.-

<P>The purposes of this study are to analyze post liquefaction shear strength and to explore the potential use of wave-based techniques to monitor liquefaction and post liquefaction response. The first part presents a detailed analysis of triaxial test results to identify robust strength criteria. The second part documents experimental data on the characterization of liquefaction events with P-wave reflection imaging and S-wave trans-illumination techniques. The relevance of multiple coexisting temporal and spatial scales is highlighted. The following results are obtained: 1) the post liquefaction shear strength can be estimated within the framework of critical state soil mechanic; 2) the P-wave reflection images obtained before and after liquefaction represent the depression of the soil-water interface; 3) excess pore pressure migration from liquefied deep layers may cause zero-effective stress in dilative shallow layers. P-wave reflection is a valuable tool to monitor the evolution of subsurface structures and S-wave trans-illumination technique can be used to yield a comprehensive picture of the spatial evolution of liquefaction.</P>

Fracture Strength of Ceramic Bracket Tie Wings Subjected to Force Direction

Kim, Kyoung Nam,Lee, Sang Bae,Kim, H.J.,Choi, J.S.,Kim, Kwang Mahn,Hwang, C.J. Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.330-332 No.1

<P>In this study, the effects of bracket designs and force direction on fracture strength of alumina bracket were evaluated. Two differently designed alumina brackets (MISO, HT Co., Ltd., Seoul, Korea) were tested. Each bracket was bonded with orthodontic adhesive to stainless steel cylinder. Compressive force was applied to the tie wing of bracket at 30°, 60°, and 90° to the long axis of the test device. Fracture strengths were assessed by using a universal testing machine (Instron 3366, Instron Co., Ltd., U.S.A.). Fractured bracket surfaces were examined using SEM. Statistical analysis was performed by using SPSS 9.0 for Windows program. Paired samples t-tests and Kruskal-wallis tests were used at P<0.05. The fracture strength ranged from 150 N with the occlusal wing to 63 N with the cervical wing in bracket A. A significant difference was founded in fracture strength between the bracket designs and force directions. Based on this result, it could be concluded that bracket designs and force direction was important rule to improve fracture strength of ceramic bracket.</P>

Preparation and Standardization of Method for Valuable Metals Analysis in Seawaters

Yoon, Hyeon,Shin, Mi Young,Yoon, Cheol Ho,Lee, Jae Chun,Chung, Kang Sup Trans Tech Publications, Ltd. 2007 Materials science forum Vol.544 No.-

<P>A direct analytical technique was developed and tested for correct estimation of recovery of Eco-elements such as Li, B, Br, in the seawater, and three processed seawaters from Hanjoo Co. Ltd. The reliability of recovery technique and the correct estimation of total recoveries become a major interest before the launch of pilot plant. High matrix solutions are frequently affected in analyte response during instrumental analysis as the concentration of major component changed drastically. To overcome such a complication during standard sample preparation and a better application in pilot plant, a modified matrix matching standard addition method was developed and the reliability was checked. The detection limit of elements in several seawaters analyzed by applying the modified matrix matching standard addition method were 0.144 - 0.258-g/dm3 for lithium, 0.0.013 - 0.18mg/dm3 for boron, and 4.23 - 17.8mg/dm3 for bromine. The instrumental analysis was carried by AAS for lithium and ICP-AES for boron and bromine.</P>

Wear Characteristics of Low Temperature Degradation-Free Zirconia/Alumina Composites in a Point Contact Condition

Lee, Kwon Yong,Kim, Hwan,Kim, D.W.,Kim, Dae Joon,Lee, Myung Hyun,Seo, Won Seon Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.342-343 No.-

<P>The sliding wear of four different compositions of novel low temperature degradation-free zirconia/alumina (LTD-free Z/A) composites were characterized in a ceramicceramic point contact pair. The wear tests were performed by a pin-on-disk type wear tester in a linear reciprocal sliding motion with a point contact in both dry and bovine serum lubricated conditions at room temperature. For the dry sliding wear tests, AZ-2 (20 vol% (Y,Nb,Ce)-TZP/ 80 vol% Al2O3) showed the best wear resistance among four kinds of LTD-free Z/A composites. For the bovine serum lubricated sliding wear tests, wear was too little to be measured for all kinds of Z/A composites. These novel LTD-free Z/A composites having excellent wear resistance demonstrated a potential as the alternative materials for the ceramic- ceramic contact pairs of femoral head and acetabular liner in total hip replacement.</P>

Recovery of Metal Values from Spent Lithium Primary Battery

Shin, Shun Myung,Lee, Dong Won,Kang, Chang Yong,Wang, Jei Pil Trans Tech Publications, Ltd. 2013 Applied mechanics and materials Vol.432 No.-

<P>This document explains and demonstrates how to prepare your camera-ready manuscript for <I>Trans Tech Publications</I>. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc. There should be 60 pounds of space above the caption and 6 pounds of space below it before the text continues. There should be 6 pounds of space above other information of the author, such as name, address and so on. Corresponding author is optional.</P>

Application of Filtration System to Control Urban Non-Point Pollution

Kim, Seog Ku,Kim, Young Im,Lee, Byung Cheol,Kang, Sung Won,Kang, Bong Moon,Kwak, Pill Jae,Ahn, Jae Hwan Trans Tech Publications, Ltd. 2007 Materials science forum Vol.544 No.-

<P>Runoff from bridge impermeable surface is discharged directly into the receiving river or sewage pipe. However, generally, a bridge does not have sufficient space to place some treatment system. In this study, therefore, we investigated the down-flow filtration using expended polypropylene media (EPM) to treat runoff from bridge. Experiments were conducted employing down-flow filtration column (dh, 50600mm) to investigate the removal efficiency of pollutants. The EPM5, EPM10, EPM15 and f-EPM10 filters were developed from high molecular material, and were classified by different foaming rates and present of functional material. The experiment using f-EPM10 showed good hydraulic filtration performance without overflow for 1hr. But overflow, in the experiments using EPM5, EPM10 and EPM15, was observed within 1hr. Since f-EPM contains functional material, that can be improved water flow without clogging. The total SS removal efficiency of filtration equipment was rapidly decreased after overflow. In addition, a down-flow experiment, having slope of 15°, to avoid SS deposition at top of the column was carried out. Though SS deposition was found to be similar in two types flow, the flow of down-flow experiment, having slope of 15°, made progress without overflow for 3hr. This is because deposited SS didn’t intercept water inflow.</P>

Anomalous Rolling and Annealing Textures of Cold Rolled Copper Foils

Kim, Su Hyeon,Han, Seung Zeon,Kim, Chang Joo,Ok, Soon Young,Hwang, In Youb,Yin, Fu Xing Trans Tech Publications, Ltd. 2007 Materials science forum Vol.558 No.-

<P>Copper foils cold rolled up to 92% reduction exhibited a low intensity of the β-fiber texture and a high intensity of the cube and RD (rolling direction)-rotated cube components. After annealing, the recrystallization texture of the foils could be characterized by the mixture of the cube and the S components. An initial strong cube texture with a large grain size might remain a less developed rolling texture component, cube or RD-rotated cube, which would be the source of the S component in the recrystallization texture.</P>

Real-Time Geometric Error Compensation in Micro Grooving the Workpiece with Large Surface Area

Kang, D.B.,Son, S.M.,Ahn, J.H. Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.339 No.-

<P>A workpiece with a large surface area is likely to be uneven due to form error and waviness. These geometric disturbances can cause inaccurate micro shapes to be formed when micro features are micro-grooved into the surface and cause the resulting workpiece to fail to function as desired. Thus, the real-time monitoring and compensation is required to guarantee the form accuracy of micro features while machining the workpiece with a large surface area. In this study, a method is suggested for real-time measurement and compensation of geometric errors for the micro grooving of a large flat surface using a laser displacement sensor placed ahead of the cutting tool. Experimental results show that the compensated surface profiles fit the measured ones within an allowable tolerance even at cutting speeds as high as 200 mm/s.</P>

Synthesis of Iron Oxide Nanowires by Heating Iron Foils

Kim, Hyoun Woo,Shim, S.H.,O, B.H.,Lee, S.G.,Park, S.G.,Lee, El Hang Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.342-343 No.-

<P>We have fabricated the iron oxide nanowires directly from iron foils through the simple heating in N2 ambient. We have characterized the samples by means of scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray (EDX) spectroscopy, and selected area diffraction pattern. The EDX spectrum revealed that the nanowires contained elements of Fe and O. The iron oxide nanowires were crystalline with diameters in the range of 30-200 nm. We have discussed the possible growth mechanisms.</P>