• Transactions of Materials Processing
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• v.27 no.3
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• pp.165-170
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• 2018

In order to increase the lifetimes of cold forging dies, insert rings are generally used. In this study, an insert ring and shrunk ring of the flange upsetting die were designed for the cold forging of an automotive wheel nut. The Stress distribution occurring in the die during forging was simulated using a commercial finite element analyzing program. The effects of the fitting interference and inclined angle of the insert ring on the compressive stress of the die inside were also investigated. The simulated data were compared with the real lifetimes of the forging dies. The maximum compressive stress acting on the edge of a forging die should have the most influence on die lifetime, an idea which could help develop the die design with the longest lifetime. The design of the most optimal forging die with the longest lifetime is made possible by analyzing the maximum inner pressure and principal stress between the shrunk ring and insert ring.

• Carbon letters
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• v.8 no.4
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• pp.285-291
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• 2007

Carbon materials of various morphologies were synthesized by pyrolysis of Soap-nut seeds (Sapindus mukorossi), Jack Fruit seeds (Artocarpus heterophyllus), Date-seeds (Phoenix dactylifera), Neem seeds (Azadirachta indica), Tea leaves (Ehretia microphylla), Bamboo stem (Bambusa bambus) and Coconut fiber (Cocos nucifera), without using any catalyst. Carbon materials thus formed were characterized by SEM XRD and Raman. Carbon thus synthesized varied in size (in ${\mu}m$) but all showed highly porous morphology. These carbon materials were utilized as the anode in Lithium secondary battery. Amongst the various precursors, carbon fibers obtained from Soap-nut seeds (Sapindus mukorossi) and Bamboo stem (Bambusa bambus), even after $100^{th}$ cycles, showed the highest capacity of 130.29 mAh/g and 92.74 mAh/g respectively. Morphology, surface areas and porosity of carbon materials obtained from these precursors were analyzed to provide interpretation for their capacity to intercalate lithium. From the Raman studies it is concluded that graphitic nature of carbon materials assist in the intercalation of lithium. Size of cavity (or pore size of channels type structure) present in carbon materials were found to facilitate the intercalation of lithium.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.15-20
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• 2002

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable contact work but also accurate force control for the automatic assembly tasks using hydraulic manipulators. In this manuscript, we applied a compliance control, which is based on the position control by a disturbance observer for our manipulator system. A reference trajectory modification method is proposed in order to achieve accurate force control even though the stiffness and the position of the environment change. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved under various environment conditions. The proposed force control algorithm is applied to the approaching of bolt and the wrenching of nut tasks as one typical task in the maintenance work of live power electric line and is experimentally confirmed very effective for the task.

• Journal of the Korea Furniture Society
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• v.22 no.3
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• pp.219-229
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• 2011

Sick building syndrome symptoms that are experienced by building occupants may be caused by toxic substances such as formaldehyde and VOCs, which are known to be emitted from building materials and wood composite products such as wood-based panel, furniture, engineered flooring and construction adhesive. In Korea, the use of wood composite products for indoor environments has increased over the last decade. Recently, wood composite products have been installed in approximately 95% of newly constructed residential buildings. The use of these products has resulted in problems related to human health, and consequently a realization about the importance of indoor air quality. In addition, consumer demand is increasing for natural materials because conventional building materials and wood composite products are made by adding urea-formaldehyde resin or they contain formaldehyde-based resin. More recently, many efforts have been made to reduce formaldehyde emission from building materials that laid in the indoor environment. Especially, if conventional formaldehyde-based adhesives are replaced with green adhesives for residential spaces, it is possible to reduce most of the emission amounts of formaldehyde in indoor environments. In line with this expectation, many researches are being conducted using natural materials such as tannin and cashew nut shell liquid (CNSL). This study discussed the affects and possibilities of green adhesives to reduce formaldehyde emission in indoor environments.

• KSBB Journal
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• v.5 no.4
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• pp.341-345
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• 1990

The composition of triglyceride in the oil of walnut and pine-nut were analysed quantitatively by Tri-analysis column of HPLC. The results were as follows: 1. The compositions of triglyceride of pine-nut oil were $C_{52}=31.55%,\;C_{44}=20.72%,\;C_{54}=17.52%,\;C_{34}=15.24%,\;C_{56}=12.50%$ in order, respectively. 2. The compositions of triglyceride of walnut oil were $C_{44}=38.66%,\;C_{52}=29.47%,\;C_{54}=16.53%,\;C_{34}=11.12%,\;C_{50}=1.51%$ in order, respectively.

• 전자공학회논문지 IE
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• v.48 no.1
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• pp.16-24
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• 2011

In this paper, we developed a auto sorting system for T type welding nut using a vision inspector. We used edge and thread detection with histogram of image which is captured by machine vision camera. We also used a binary morphology operation for a detection of spot. As a result we performed numeric inspection of 0.1mm accuracy. This is impossible in old sorting system and inspector with naked eye. Also, we reduced the manufacturing unit cost to 25% and improved a production efficiency to 330%.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.205-212
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• 2003

In this study, in order to investigate a modeling technique of the structure with bolted joints, four kinds of finite element model are introduced; a solid bolt model, a coupled bolt model, a spider bolt model, and no bolt model. All proposed models take account on prestrained effect and contact behavior of flanges to be joined. Among these models, a solid bolt model, which is modeled by using a 3-D solid element and a surface-to-surface contact element between the head/nut and the flange interfaces, has the best accurate responses compared with the experimental results. In addition, coupled bolt model, which couples the degree of freedom between the head/nut and the flange, shows the best effectiveness and usefulness in view of computational time and memory usage. Finally, the bolt model proposed here is adopted for structural analysis of a large diesel engine of a ship consisting of several parts which is connected by long stay bolts.

• Korean Journal of Pharmacognosy
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• v.29 no.1
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• pp.28-34
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• 1998

It has been known that diseases related with aging or cancer result, at least in part, from free radicals, and antioxidants may reduce or prevent the abnormalities associated with free radical formation via its scavenging action. Thus, this study was carried out to investigate the antioxidative and antimicrobial activities of nut species for the purpose of developing antioxidant from natural products. Antioxidant activities of four kinds of nuts such as chestnut, groundnut, walnut and acorn were examined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. The extracts from chestnut hull and acorn barnyard millet showed strong antioxidative activities among 10 samples tested. Because of their highest antioxidative activity among 10 samples, radical scavenging effects of 4 different extract compartments (Hexane, EtOAc, BuOH and $H_2O$ extracts) from chestnut hull and acorn barnyard millet, were further examined by DPPH method. EtOAc and BuOH extracts exhibited antioxidative activities similar to those of natural, tocopherol or synthetic antioxidants, BHA. These findings demonstrates that major fraction of the antioxidative activity of chestnut hull or acorn barnyard millet was the EtOAc and BuOH extract compartments. However, antimicrobial activities against food-related bacteria and yeasts was relatively weak.

• Research in Plant Disease
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• v.24 no.4
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• pp.265-275
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• 2018

Cashew (Anacardium occidentale L.) is an export crop and source of income in Tanzania. However, its productivity is challenged by insect pests and diseases. Cashew Leaf and Nut Blight Disease (CLNBD) caused by Cryptosporipsis spp. has been cited as one of the most devastating diseases in Tanzania. Studies were conducted to investigate incidences and severities of CLNBD on cashew in farmers' fields and elite cashew hybrids developed in 1996 and 1998 in eastern and southern zones of Tanzania. Furthermore, a screen house experiment was conducted to screen these hybrids against CLNBD at Naliendele Agricultural Research Institute (NARI), Mtwara, Tanzania. The results indicated significant differences (P<0.001) in CLNBD incidences and severities in cashew in farmers' fields across Bagamoyo, Nachingwea and Mtwara districts. Further, there were significant differences (P<0.001) among hybrids in CLNBD severities in the screen house experiment. In ranking the elite cashew hybrids, 38 were tolerant and 14 were susceptible to CLNBD. This observation suggests that elite cashew hybrids developed in 1996 and 1998 are more tolerant to CLNBD compared to cashew found in farmers' fields. These findings strongly suggest that the elite cashew hybrids can be recommended for commercial farming in Tanzania.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.96-102
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• 2021

Hexagonal bolt, nut, fittings, and high-pressure valves with special alloy play an important role in many industrial products. Numerical analysis was conducted to obtain data for designing a new drawing system. This study aims to predict the rolling force of the new drawing system compared to that of the established drawing system. The rolling force of the new drawing system was predicted using numerical analysis by assuming that it is in proportion to deformation. The rolling forces of Mo, Ti, and W were approximately 1.4, 0.5, and 2.5 times those of SUS. Because the values of ultimate strength of special alloys were more close to numerical analysis, the values of ultimate strength could be used to predict the rolling force of the new drawing system without numerical analysis in field.