목적 : 본 연구는 최저임금적용제외인가 작업능력평가를 위한 역량지표를 개발하여 생산성과 함께 장애인 근로자의 직무수행능력을 평가하는 데 활용하고자 한다. 연구방법 : 선행연구를 통해 장애인근로자의 작업능력평가 관련 지표를 도출한 후, 3명의 전문가의 검증을 거쳐 델파이 조사지 초안을 제작하였다. 그 후 20명의 전문가에게 델파이 연구를 통해 장애인근로자의 최저임금적용제외인가 작업능력평가를 위한 역량지표를 도출하고자 하였다. 결과 : 총 2회의 델파이 연구 결과, 인지기능, 사회기능, 작업기능, 안전보건활동 등 4개의 역량군과 숫자 처리능력, 정보활용능력 등 20개의 역량지표가 도출되었다. 결론 : 도출된 역량군 및 역량지표는 장애인근로자의 직무수행능력을 평가하는데 활용하여 최저임금적용제 외인가 작업능력평가의 타당성을 높일 수 있을 것이다. 향후 연구에서는 각 역량군과 역량지표에 대한 척도를 개발하고, 현장에 적용하여 타당도를 검증해야 할 것이다.

Motors are becoming an environment-friendly alternative around the world. Environment-friendly automobile parts in particular require high quality and productivity. To improve these requirements, we studied a manufacturing technology called mold technology. A disadvantage of mold mass-production is a fatigue failure after a relatively large amount of friction and pressure on the processed products. Eventually, this leads to problems of repair costs, production stoppages, and quality defects. To address these problems, a surface- treatment technique is often used to improve mechanical properties by coating the mold surfaces. In this study, we measured the abrasion on (1) Tungsten Carbide punch and (2) TiAlCrN coated punch during the mold mass-production of the cold-rolled steel plate motor core made with SCP-1 (thickness of 1.0mm). With the extracted data, it is proved that using TiAlCrN coated punch affects the reduction of the inner diameter damage of the product. Furthermore, our goal is to reduce repair cost and improve productivity by predicting the lifespan of the mold and identifying the time expectancy of grinding, maintenance, and repair of the mold.

The cold rolling workability and mechanical properties of two new alloys, designed and cast Al-5.5Mg-2.9Si and Al-7Mg-0.9Zn alloys, were investigated in detail. The two alloy sheets of 4 mm thickness, 30 mm width and 100 mm length were reduced to a thickness of 1 mm by multi-pass rolling at ambient temperature. The rolling workability was better for the Al-7Mg-0.9Zn alloy than for the Al-5.5Mg-2.9Si alloy; in case of the former alloy, edge cracks began to occur at 50% rolling reduction, and their number and length increased with rolling reduction; however, in the latter alloy, the sheets did not have any cracks even at higher rolling reduction. The mechanical properties of tensile strength and elongation were also better in the Al-7Mg-0.9Zn alloy than in Al-5.5Mg-2.9Si alloy. Work hardening ability after cold rolling was also higher in the Al-7Mg- 0.9Zn alloy than in the Al-5.5Mg-2.9Si alloy. At the same time, the texture development was very similar for both alloys; typical rolling texture developed in both alloys. These differences in the two alloys can primarily be explained by the existence of precipitates of Mg2Si. It is concluded that the Al-7Mg-0.9Zn alloy is better than the Al-5.5Mg-2.9Si alloy in terms of mechanical properties.

Roller-compacted concrete or RCC is a dry concrete that requires compaction in order to reach its final form. Its consistency is usually overlooked due to its inconsistency and lack of subjective nature. To work with this concrete, however, appropriate consistency is required for supporting the compacting machine and minimizing compaction energy. Due to transportation and compaction time, maintaining proper consistency within a period of time is also necessary. Vebe time, a represent parameter of dry concrete consistency, ranged from 30 to 75 seconds is considered appropriate for RCC in pavement application. The purpose of this study is to improve workability of this concrete which consisted of improving its consistency and maintaining it within the working time. It was confirmed that the workable time of a normal RCC is less than one hour. Moreover, it was found that Vebe time drops when water content increases and goes up when sand by aggregate ratio increases. Various admixtures were also employed in this study in order to improve the workability of this concrete. Poly Naphtalene Sulfonate superplasticizer, particularly, was found to be the most effective in term of lowering down Vebe time and maintaining it. With just 0.3% of this admixture, the working time of RCC can be extended up to four hours without affecting its compressive strength.

The purpose of this experimental research is to evaluate the workability and strength properties of hybrid fiber reinforced concrete containing amorphous steel fiber and organic fiber. For this purpose, the hybrid fiber reinforced concrete containing amorphous steel fiber(ASF) with polyamide(PA) and polyvinyl alcohol(PVA) fiber, respectively were made according to their total volume fraction of 0.5% for water-binder ratio of 33%, and then the characteristics such as the workability, compressive strength, and flexural strength of those were investigated. It was observed from the test results that the workability and compressive strength at 7 and 28 days were decreased and the flexural strength at 7 and 28 days was increased with increasing ASF and decreasing organic fiber.

Li의 양과 Al의 양을 달리한 α(HCP) 단상 및 α(HCP)+β (BCC) 2상 조직인 Mg-Li-Al합금을 시료로 하여 이 합금의 가공성과 시효경화륵성을 조사한 결과 α단상보다는 α+β 2상 조이,α+β 2상조직에서는 Al양이 많을수록 가궁성이 증가하였으며 Mg-8.08Li-4.26Al의 경우 가공한계값은 62%였다. 이와같이 가공성이 증가한 이유는 basal plane뿐만 아니라 pyramidal plane과 prism plane에서도 슬립이 일어났기 때문이다. α단상의 경우 MgLi2 Al(θ)의 석출이 일어나지 않았으나 α+β 2상 조직의 곁우 β상 내에서 θ의 석출에 의한 피크경도같이 나타났으며, 2상 조직의 경우 경도값은 Al양이 많을수록 증가하였는데 이것은 Al양의 증가에 따른 Al Partition에 의한α 상의 강화와 β상에서의 석출물 증가에 의한 것으로 생각된다.

This paper presents the findings of the study conducted to evaluate workability and compressive strength characteristics of rapid-setting concrete containing metakaolin. The experimental variable selected was the rate of cement replacement with metakaolin at 0, 5, 10, and 15 percent. The findings are summarized as follows: compared with the control specimens with no replacement rate, the workability and compressive strength of the concrete with 5% of cement replaced with metakaolin were comparable to those of control specimens at 4hours; however, at 72 hours, the compressive strength of the concrete with the same replacement rate was larger than the strength of the control specimens by 4.1%, while no increase in strength was observed at higher replacement rates, implying that the optimum replacement rate of cement with metakaolin is 5%.

This study was conducted to examine the workability of LEFC in relation to the types and the mix ratio of different foaming agents. The foam agents act as lightweight aggregates in the concrete matrix and provide an alternative to obtaining the adequate strength level for the foam concrete. The results of the test showed that the synthetic foam agents were able to act properly as replacements for the lightweight aggregates.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

This study was conducted to examine the workability of LEFC in relation to the types and the mix ratio of different foaming agents. The foam agents act as lightweight aggregates in the concrete matrix and provide an alternative to obtaining the adequate strength level for the foam concrete. The results of the test showed that the synthetic foam agents were able to act properly as replacements for the lightweight aggregates.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

선반 스크랩은 금속 가공 공정에서 선반 및 밀링 작업에 의해 발생된 철강제품의 부산물이므로, 섬유보강 시멘트 복합체 제작시 이 를 활용할 경우 경제성뿐만 아니라 환경 친화적인 효과를 가져온다. 따라서 이 연구의 목적은 강섬유 대체재료로서 선반 스크랩의 활용 방안을 제시하기 위하여 선반 스크랩 보강 시멘트 복합체(LSRCCs)의 작업성 및 강도 특성을 평가하는 것이다. 이를 위하여 금속 가공공장에서 3종류 의 선반 스크랩을 채취한 후 폭 2 mm, 길이 40 mm로 가공하여 LSRCCs를 제작하였다. 그 결과, LSRCCs의 작업성은 플레인 모르타르보다 약 간 저하되었고, 휨강도는 크게 개선되었으며, 선반 스크랩의 종류가 LSRCCs의 특성에 다소 영향을 미치는 것으로 나타났다.

In this study, cement-based accelerators, which have an advantage of preventing early frost and in developing early strength in cold-weather. Then, whether it can be secured the operating time by controlling the response time in early-stage and can be developed due to the accelerator's function, as evaluated by testing.

Underground material and to secure any other appropriate waterproofing method for improving the workability experiments on non-woven fabric weight is selected. As a result, the appropriate non-woven fabric weight of 140 g/㎡ was confirmed.