• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.143-148
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• 2001

ILSAC GF 3/API SL specification will be adopted in July 2001. The background and characteristics of GF3 specification is reviewed. GF3 specification consists of five new engine tests, two new bench tests and new limits on three bench tests currently used to define ILSAC GF-2. GF 3 engine oil shows good performance compared to GF2 engine oil in fuel efficiency, protecting ability the emission catalyst and high temperature oxidation stability.

• KSTLE International Journal
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• v.3 no.1
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• pp.26-29
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• 2002

The International Lubricant Standardization and Approval Committee (ILSAC) GF-3 passenger car engine oil specification has been introduced commercially in July 2001. The new specification oil provides superior performance in terms of fuel economy, control of high temperature deposits, and oil consumption. These enhanced performances of GF-3 engine oil need high quality base oil as well as a better additive system. In this paper, the effect of base oil on various performances of ILSAC GF-3 engine oil was investigated. From the GF-3 sequence engine tests, Group III base oil shows better performance in fuel economy retention, oxidation and varnish control than combination of group III and group II or group III and group 1.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.278-287
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• 1998

The purpose of this study was to compare the physical properties between high copper amalgam and gallium restorative material. In this study, the specimens for the 4 experimatal groups (Valiant, Valiant PhD, Gallium Alloy GF II. Gallium Alloy GF II triturated with some addition of alcohol) were prepared in the manner of which stated in ADA specification No.1 for amalgam alloy. And then, measured and compared the value of compressive strength. creep, and dimensional change during hardening of each sample. The results were as follows: 1. In the compressive strength, the Valiant-lathe cut type high copper amalgam-had the highest value of strength(p<0.05), and the Valiant PhD-admixed type high copper amalgam-showed the higher value of strength than the Gallium Alloy GF II(p<0.05) but had no significant difference with Gallium Alloy GF II triturated with some addition of alcohol(p>0.05). 2. In the creep. the Valiant PhD showed the highest value of creep (p<0.05), but there was no significant difference between Gallium Alloy GF II and Valiant(p>0.05). 3. In the dimensional change during hardening, no two groups were significantly different at the 0.050 level. 4. There was no significant difference between Gallium Alloy GF II and the same material which was triturated with some addition of alcohol(p>0.05).

• Composites Research
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• v.34 no.4
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• pp.241-248
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• 2021

As the electric vehicle market grows, there is an issue of light weight vehicles to increase battery efficiency. Therefore, it is going to replace the battery module cover that protects the battery module of electric vehicles with high strength/high heat-resistant polymer composite material which has lighter weight from existing aluminum materials. It also aims to respond to the early electric vehicle market where technology changes quickly by combining 3D printing technology that is advantageous for small production of multiple varieties without restrictions on complex shapes. Based on the composite material mechanics, the critical length of glass fibers in short glass fiber (GF)/polycarbonate (PC) composite materials manufactured through extruder was derived as 453.87 ㎛, and the side feeding method was adopted to improve the residual fiber length from 365.87 ㎛ and to increase a dispersibility. Thus, the optimal properties of tensile strength 135 MPa and Young's modulus 7.8 MPa were implemented as GF/PC composite materials containing 30 wt% of GF. In addition, the filament extrusion conditions (temperature, extrusion speed) were optimized to meet the commercial filament specification of 1.75 mm thickness and 0.05 mm standard deviation. Through manufactured filaments, 3D printing process conditions (temperature, printing speed) were optimized by multi-optimization that minimize porosity, maximize tensile strength, and printing speed to increase the productivity. Through this procedure, tensile strength and elastic modulus were improved 11%, 56% respectively. Also, by post-processing, tensile strength and Young's modulus were improved 5%, 18% respectively. Lastly, using the FEA (finite element analysis) technique, the structure of the battery module cover was optimized to meet the mechanical shock test criteria of the electric vehicle battery module cover (ISO-12405), and it is satisfied the battery cover mechanical shock test while achieving 37% lighter weight compared to aluminum battery module cover. Based on this research, it is expected that 3D printing technology of polymer composite materials can be used in various fields in the future.

• Analytical Science and Technology
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• v.23 no.1
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• pp.1-14
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• 2010

It is of importance that all countries in worldwide, including EU and China, have adopted the Restrictions on the use of certain Hazardous Substances (RoHS) for all electronics. IEC62321 document, which was published by the International Electronics Committee (IEC) can have conflicts with the standards in the market. On the contrary Publicly Accessible Specification (PAS) for sampling published by IEC TC111 can be adopted for complementary application. In this work, we tried to find a route to disassemble and disjoint cellular phone sample, based on PAS and compare the screening methods available in the market. For this work, the cellular phone produced in 2001, before the regulation was born, was chosen for better detection. Although X-ray Fluorescence (XRF) showed excellent performance for screening, fast and easy handling, it can give information on the surface, not the bulk, and have some limitations due to significant matrix interference and lack of variety of standards for quantification. It means that screening with XRF sometimes requires supplementary tool. There are several techniques available in the market of analytical instruments. Laser ablation (LA) ICP-MS, energy dispersive (ED) XRF and scanning electron microscope (SEM)-energy dispersive X-ray (EDX) were demonstrated for screening a cellular phone. For quantitative determination, graphite furnace atomic absorption spectrometry (GF-AAS) was employed. Experimental results for Pb in a battery showed large difference in analytical results in between XRF and GF-AAS, i.e., 0.92% and 5.67%, respectively. In addition, the standard deviation of XRF was extremely large in the range of 23-168%, compared with that in the range of 1.9-92.3% for LA-ICP-MS. In conclusion, GF-AAS was required for quantitative analysis although EDX was used for screening. In this work, it was proved that LA-ICP-MS can be used as a screening method for fast analysis to determine hazardous elements in electrical products.