• Earthquakes and Structures
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• 제8권3호
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• pp.619-637
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• 2015

A field based non-destructive hardness method is being developed to determine plastic strain in steel elements subjected to seismic loading. The focus of this study is on the active links of eccentrically braced frames (EBFs). The 2010/2011 Christchurch earthquake series, especially the very intense February 22 shaking, which was the first earthquake worldwide to push complete EBF systems into their inelastic state, generating a moderate to high level of plastic strain in EBF active links for a range of buildings from 3 to 23 storeys in height. Plastic deformation was confined to the active links. This raised two important questions: what was the extent of plastic deformation and what effect does that have on post-earthquake steel properties? A non-destructive hardness test method is being used to determine a relationship between hardness and plastic strain in active link beams. Active links from the earthquake affected, 23-storey Pacific Tower building in Christchurch are being analysed in the field and laboratory. Test results to date show clear evidence that this method is able to give a good relationship between plastic strain and demand. This paper presents significant findings from this project to investigate the relationship between hardness and plastic strain that warrant publication prior to the completion of the project. Principal of these is the discovery that hot rolled steel beams carry manufacturing induced plastic strains, in regions of the webs, of up to 5%.

• Smart Structures and Systems
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• 제20권6호
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• pp.709-728
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• 2017

This disquisition proposes a nonlocal strain gradient beam theory for thermo-mechanical dynamic characteristics of embedded smart shear deformable curved piezoelectric nanobeams made of porous electro-elastic functionally graded materials by using an analytical method. Electro-elastic properties of embedded curved porous FG nanobeam are assumed to be temperature-dependent and vary through the thickness direction of beam according to the power-law which is modified to approximate material properties for even distributions of porosities. It is perceived that during manufacturing of functionally graded materials (FGMs) porosities and micro-voids can be occurred inside the material. Since variation of pores along the thickness direction influences the mechanical and physical properties, so in this study thermo-mechanical vibration analysis of curve FG piezoelectric nanobeam by considering the effect of these imperfections is performed. Nonlocal strain gradient elasticity theory is utilized to consider the size effects in which the stress for not only the nonlocal stress field but also the strain gradients stress field. The governing equations and related boundary condition of embedded smart curved porous FG nanobeam subjected to thermal and electric field are derived via the energy method based on Timoshenko beam theory. An analytical Navier solution procedure is utilized to achieve the natural frequencies of porous FG curved piezoelectric nanobeam resting on Winkler and Pasternak foundation. The results for simpler states are confirmed with known data in the literature. The effects of various parameters such as nonlocality parameter, electric voltage, coefficient of porosity, elastic foundation parameters, thermal effect, gradient index, strain gradient, elastic opening angle and slenderness ratio on the natural frequency of embedded curved FG porous piezoelectric nanobeam are successfully discussed. It is concluded that these parameters play important roles on the dynamic behavior of porous FG curved nanobeam. Presented numerical results can serve as benchmarks for future analyses of curve FG nanobeam with porosity phases.

• 산업경영시스템학회지
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• 제38권4호
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• pp.72-79
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• 2015

A number of plating companies have been exposed to the risk of fire due to unexpected temperature increasing of water in a plating bath. Since the companies are not able to forecast the unexpected temperature increasing of water and most of raw materials in the plating process have low ignition temperature, it is easy to be exposed to the risk of fire. Thus, the companies have to notice the changes immediately to prevent the risk of fire from plating process. Due to this reason, an agile and systematic temperature monitoring system is required for the plating companies. Unfortunately, in case of small size companies, it is hard to purchase a systematic solution and be offered consulting from one of the risk management consulting companies due to an expensive cost. In addition, most of the companies have insufficient research and development (R&D) experts to autonomously develop the risk management solution. In this article, we developed a real time remote temperature monitoring system which is easy to operate with a lower cost. The system is constructed by using Raspberry Pi single board computer and Android application to release an economic issue for the small sized plating manufacturing companies. The derived system is able to monitor the temperature continuously with tracking the temperature in the batch in a short time and transmit a push-alarm to a target-device located in a remoted area when the temperature exceeds a certain hazardous-temperature level. Therefore, the target small plating company achieves a risk management system with a small cost.

• 식품과학과 산업
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• 제49권4호
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• pp.64-69
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• 2016

The potentialities of 3D printing technology are discussed from technical and research-oriented perspectives for industrial manufacturing of a variety of food products. Currently, 3D printing technology has advanced to enable us to process or cook innovative foods. However, food-based materials for 3D printing are still limited in terms of eating qualities, nutritional values and functionality as well as industrial production. Therefore, this uprising issue on alternative food processing techniques especially focused on the exploration of new food materials combined with these 3D printing technologies needs to be re-spotlighted, and then solved to pave the way to this innovative and sensational area of investigation with more accessibility. In this review, previous research work and industrial applications conducted by frontier research groups in this field are covered, then to open discussion for future research on the 3D printing of food.

• 한국정보통신학회논문지
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• 제23권10호
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• pp.1298-1304
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• 2019

9.11 테러 이후 미국을 비롯한 선진국들의 해운물류 안전 보안체계가 크게 강화되었다. 해운물류의 검색에는 강력한 방사선을 투과하여 컨테이너의 내부를 확인하는 컨테이너 검색기 시스템을 주로 사용하는데, 국내에서는 전량 도입품을 적용하여 운용 중이며 국산화 개발에 대한 요구가 증가하고 있다. 이에 본 논문에서는 컨테이너 검색기 시스템의 핵심 구성요소인 X-Ray 어레이 검출 모듈 신호처리 시스템을 개발하여 제안한다. 아날로그 및 디지털 신호처리부를 통합형 하드웨어로 제작하였으며, X-선 데이터의 실시간 수집과 분석을 위해 FPGA 로직과 소프트웨어를 구현하여 시험하였다. 구현된 시스템은 기존 항만에서 사용되는 도입품 대비 해상도와 소비전력 면에서 우세하다.

• 한국산업융합학회 논문집
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• 제25권1호
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• pp.79-86
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• 2022

In general, since the types and types of ships, so complex and various variables are included to measure the amount of construction work. In addition, it is mot easy to predict the schedule or the number of working hours before ship construction, and it is also mostly inaccurate. As a result, the master plan is manually drawn up by the expert's experience, but there are limitations due to various factors. Medium and large shipyards are operating APS(Advanced Planning and Scheduling) system that reflects industrial characteristics to improve productivity in the planning stage, and utilize information from systems such as ERP(Enterprise Resource Planning) system and MES (Manufacturing Execution System). On the other hand, small shipyards rely mostly on manual work such as Excel work based on the experience of the workers. Therefore, this study intends to develop a master plan management system that can efficiently manage the production process from the business planning stage in consideration of the characteristics of small shipyards.

• 한국전기전자재료학회논문지
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• 제36권3호
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• pp.292-297
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• 2023

Triboelectric devices are attracting attention from researchers as self-powered electronic systems that can instantly convert mechanical input into electrical energy output. To improve triboelectric energy harvesting performance, increasing the number of contacts as well as the contact area has been carried out by numerous researchers. In this study, we design a shaker-type energy harvester which is called as maracas triboelectric generator (M-TEG), inspired by the structure of maracas, one of the musical percussion instruments. A tripod frame is inserted to the inside of a cylindrical case, which is a device with the electrodes of aluminum and copper. Then, the triboelectric energy harvesting characteristics between polypropylene (PP) balls and the electrodes are measured. The M-TEG with the frame generates the energy harvesting signals up to ~100 V and ~2.5 ㎂ due to larger contact area and numbers, which enhances the voltage and current output by 250% and 610% compared to that without the frame, respectively. This study presents the feasibility of self-powered sensors and toys using improved triboelectric energy performance with a low-cost and simple manufacturing process in the interesting structure.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.73-79
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• 2017

Rapidly expanding population in the Kingdom of Saudi Arabia has a massive impact to put pressure on the shortage of housing and existing infrastructure. With average population growth rate of 1,9% yearly, the population in Saudi Arabia is projected to increase from 31 million in 2015 to 37 million in 2025. According to the housing ministry, Saudi Arabia needs to provide 3.3 million units to meet the demand in 2025, which is about 300,000 unit a year. In the past 40 years, using the conventional construction method, the Saudi construction industry was only able to build about 150,000 units per year. To meet the demand gap for the housing shortage, a new approach and innovation in construction methods are needed. Industrialized construction as an approach in construction methods has been studied and implemented in some countries that experienced similar corncerns. Industrialized construction can be defined as the implementation of manufacturing methods to construction-related activities to improve quality, reduce cost and project duration. Compared to the conventional construction method, prefabrication as industrialized construction methods has reduced construction labor on-site by 9.5%, construction project duration by 20%, and construction waste by 56%. It improves the quality, durability and cost saving not only for construction project owners, but also construction contractors. This paper discusses the possibility of 'industrialization' of building system in the Kingdom of Saudi Arabia as a solution for the housing shortage. It is an initial part of a study aims to develop a framework to develop industrialized building system in the Kingdom of Saudi Arabia. The is paper based on extensive literature review and case studies.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.44-52
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• 2002

Low temperature thermal desorption (LTTD) has become one of the cornerstone technologies used for the treatment of contaminated soils and sediments in the United States. LTTD technology was first used in the mid-1980s for soil treatment on sites managed under the Comprehensive Environmental Respones, Compensation and Liability Act (CERCLA) or Superfund. Implementation was facilitated by CERCLA regulations that require only that spplicable regulations shall be met thus avoiding the need for protracted and expensive permit applications for thermal treatment equipment. The initial equipment designs used typically came from technology transfer sources. Asphalt manufacturing plants were converted to direct-fired LTTD systems, and conventional calciners were adapted for use as indirect-fired LTTD systems. Other innovative designs included hot sand recycle technology (initially developed for synfuels production from tar sand and oil shale), recycle sweep gas, travelling belts and batch-charged vacuum chambers, among others. These systems were used to treat soil contaminated with total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs), pesticides, polychlorinated biphenyls (PCBs) and dioxin with varying degrees of success. Ultimately, performance and cost considerations established the suite of systems that are used for LTTD soil treatment applications today. This paper briefly reviews the develpoment of LTTD systems and summarizes the design, performance and cost characteristics of the equipment in use today. Designs reviewed include continuous feed direct-fired and indirect-fired equipment, batch feed systems and in-situ equipment. Performance is compared in terms of before-and-after contaminant levels in the soil and permissible emissions levels in the stack gas vented to the atmosphere. The review of air emissions standards includes a review of regulations in the U.S. and the European Union (EU). Key cost centers for the mobilization and operation of LTTD equipment are identified and compared for the different types of LTTD systems in use today. A work chart is provided for the selection of the optmum LTTD system for site-specific applications. LTTD technology continues to be a cornerstone technology for soil treatment in the U.S. and elsewhere. Examples of leading-edge LTTD technologies developed in the U.S. that are now being delivered locally in global projects are described.

• 산업공학
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• 제25권1호
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• pp.21-30
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• 2012

In the past, buyers and suppliers met each other to find common interests off-line in exhibitions and conferences, or through personal connection. These activities were time consuming and costly. With the advent of information era, these activities moved to online market places, where buyers search for suppliers with a set of keywords that are believed to be representative of their requirements. Its fundamental assumption is that all the potential candidates are registered in a certain database. However, recently buyers want to diversify suppliers due to needs of cost competitiveness or frequent new product development. To this end, instead of choosing suppliers from the supplier pool, discovering suppliers from all over the world should be emphasized. In order to enable buyers to describe their requirements and suppliers to capture their manufacturing capabilities via online market places, the semantic differences of terms between buyers and suppliers should be resolved. The paper summarizes various supplier discovery frameworks and prototype systems, which can be employed to expose domestic small-medium enterprises into global buyers in the near future.