Maraging steel has excellent mechanical properties resulting from the formation of precipitates within the matrix through aging treatment. Maraging steel fabricated by the laser powder bed fusion (LPBF) process is suitable for applications including precise components and optimized design. The anisotropic characteristic, which depends on the stacking direction, affects the mechanical properties. This study aimed to analyze the influence of anisotropy on the wear behavior of maraging steel after aging treatment. The features of additive manufacturing tended to disappear after heat treatment. However, some residual cellular and dendrite structures were observed. In the wear tests, a high wear rate was observed on the building direction plane for all counter materials. This is believed to be because the oxides formed on the wear track positively affected the wear characteristics; meanwhile, the bead shape in the stacking direction surface was vulnerable to wear, leading to significant wear.
본 논문에서는 다이나믹크리깅 대리모델 기반 자동차 브레이크 패드 마모량 측정센서 브라켓의 설계최적화를 소개한다. 브레이크 작동시 마찰재 바닥의 온도가 600°C 이상으로 상승하고, 이 열이 전달되어 센서의 기능을 상실시킨다. 따라서 열전달을 최소화하는 브라켓 형상의 설계최적화는 필수적이다. 최적화에 소요되는 계산비용을 절감하기 위해 다이나믹크리깅 대리모델로 열전달 시뮬레 이션을 대체하였다. 다이나믹크리깅은 최적의 상관함수와 기저함수를 선정하였으며, 정확한 대리모델을 도출하였다. 최적화 결과 센 서위치의 온도가 초기모델에 비해 7.57% 감소하였으며, 이를 열전달 시뮬레이션으로 다시 한번 확인하여 대리모델 기반 최적설계가 유의미함을 검증하였다.
The purpose of this study was to develop the Functional golf inner-wear by preventing the injuries and enhancing the performance of the Golf swing by checking the influence of the wearing of the functional golf inner-wear considering golf characteristics on the Swing trajectory and Shot distance. Functional inner-wear effective for golf swing was manufactured using the sports taping method. Changes in driver and iron swing before and after wearing the functional golf inner-wear manufactured in this way were measured using trackman equipment. Measurement variables were limited to Club Speed, Attack Angle, Club Path, Ball Speed, Smash Factor, and Priority. Before and after wearing functional golf inner-wear, there were statistically significant differences in driver club speed, iron club speed, driver etch angle, iron club pass, driver ball speed, driver smash factor, iron smash factor, driver carry, iron carry, and right shoulder joint proprioceptive sensory ability. As a result, functional golf inner-wear is effective for ball speed, impact, and carry by increasing club speed and efficient swing. Future research will focus on the development of functional golf that can improve the swing ability in a short game that plays an important role in the golf game through various sports taping grafting technique, textile, special material, film, Research on functional golf inner-wear.
In the modern society, the sports industry is becoming an important industry that plays an important role in cultural exchange and economic development between countries. Along with this, the size of sports equipment manufacturers is also increasing, and especially in the archery field, domestic companies occupy a high share in the global market. However, in the case of precision accessories, foreign products are imported and used. Among the precision archery accessories, the cushion plunger is subjected to repetitive loads, and the surface damage due to wear affects the accuracy of the archery, so fatigue and wear analysis taking this into account are required. In this paper, a friction simulation was performed to calculate the fatigue life and wear amount of the cushion plunger among the precision archery accessories, and the validity of the analysis model was evaluated by comparing the friction test results.
Hybrid nanocomposites of aluminium (NHAMMCs) made from AA5052 are fabricated via stir casting route by reinforcing 12 wt% Si3N4 and 0.5 wt% of graphene for usage in aeronautical and automotive applications due to the lower density and higher strength to weight proportion. The wear characteristics of the NHAMMCs are evaluated for different axial load, rotational speed, sliding distance and sliding time based on Box-Behnken design (BBD) of response surface methodology (RSM). Orowan strengthening mechanism is identified from optical image which improves the strength of the composite. Outcomes show that with higher axial load and rotational speed, there is substantial increase in wear loss whereas with increased sliding distance and sliding time there is no considerable increase in wear loss due to the lubricating nature of the reinforced graphene particles since it has higher surface area to volume ratio. Besides, artificial intelligence approach of neuro-fuzzy (ANFIS) model is developed to predict the output responses and the results are compared with the regression model predictions. Prediction from ANFIS outplays the regression model prediction.
Abstract Purpose : To determine the perceptions of soft contact lens wearers regarding contact lens wear and care, and their knowledge of adverse effects of contact lens wear by self-assessment. Methods : An online survey using smartphone was conducted by Naver and Google questionnaires among university students who have experience wearing soft contact lenses. Results : Two hundred twenty-eight soft lens wearers were participated in the study. The average age was 20.9±1.7 years (female 72.8%; male 27.2%) were university students. Approximately 25.4% of respondents did not receive training and practices for safe soft lens wear and 14.1% evaluated themselves as poor at wearing and caring for soft lenses. The most uncomfortable symptom of soft lens wear was dryness at 76.3%, and 36.0% experienced soft lens-related adverse events. The higher type of adverse event was conjunctivitis, and the most common self-reported cause of contact lens-related adverse events was improper lens care and non-compliance to lens wear regimens. Conclusion : Based on the self-assessment of soft lens care that resulted from this survey, we believe that a more proactive approach to intervention by contact lens practitioners is still needed to prevent the risk of adverse events and improve soft lens wearer behavior. Key words : Compliance, Contact lens-related adverse events, Self-assessment, Soft contact lens Authors ORCID:†
용인 영문리유적 출토 편주형 석도 5점에 대한 사용흔을 분석하여 그 사용 방식을 추정하였다. 분 석 결과 아래쪽 날에 대해서는 기존의 사용 방식을 다시 한 번 입증하게 되었다. 구체적인 사용법은 오른손 중지에 끈을 연결하여 석도를 잡은 다음, 엄지로 벼과식물을 석도에 밀착시키고 검지로 누르 면서 손목을 비틀어 이삭을 따는 형태로 복원되었다. 측면 날에 대한 분석에서는 날을 따라 분포하는 발달된 벼과식물 접촉 광택, 날과 같은 방향의 선상흔 등이 관찰되어, 수확 후 짚 확보나 잡초 제거를 위해 날과 평행하는 방향으로 석도를 움직여 여러 줄기의 벼과식물을 한 번에 자르는 용도가 상정되 었다. 또한 앞뒷면 광택 발달 정도의 차이에 따라 오른손잡이와 왼손잡이의 사용을 구분할 수 있었으 며, 구체적인 사용법으로 직접 석도를 손에 잡고 다른 손으로 벼과식물의 윗부분을 잡은 다음 작업자 의 몸 쪽으로 석도를 당기면서 절단하는 방식이 추정되었다. 그리고 이러한 분석을 통해 편주형 석도 가 수확 현장에서 이루어지는 두 가지의 다른 작업에 대응 가능한 다목적 도구임을 확인할 수 있었다.
본 연구는 골프웨어 브랜드 전략의 기초자료를 제공하기 위해 골프웨어 브랜드의 소비가치가 태도 및 구매행동에 미치는 영향력을 검증하는데 목적이 있다. 따라서 대한민국 국민들 중 골프웨어를 구 매했던 경험이 있는 사람들을 표본으로 선정했으며, 496부의 자료를 최종분석에 도입했다. 본 연구의 자료 처리는 빈도분석과 탐색적 요인분석 및 내적일관성을 실시했다. 더불어 연구문제를 검증하기 위해 상관분 석과 단순 및 다중회귀분석을 실시했으며, 모든 자료처리는 SPSS(ver. 21.0) 프로그램을 활용했다. 본 연구 결과, 첫 번째로 골프웨어 브랜드의 소비가치가 쾌락성, 심미성, 상징성 순으로 태도에 유의한 영향이 있는 것으로 나타났다. 둘째, 골프웨어 브랜드의 태도가 구매행동에 유의한 영향을 미치는 것으로 나타났다. 셋 째, 골프웨어 브랜드의 소비가치가 쾌락성, 심미성, 상징성 순으로 구매행동에 유의한 영향이 있는 것으로 나타났다.
In this study, a survey focusing on the status of clothing interest, inconveniences resulting from clothing, preferred design items, etc. was conducted on 364 elderly women to suggest aesthetically and functionally appropriate indoor wear design for at home elderly women aged 60 years or older. The survey results showed that in general, the respondents’ interest in clothing was high, and more respondents in their 70s or older had difficulty in the action of opening and closing. With respect to considerations when purchasing clothes, color was considered more important than design as respondent’s age increased, and size was regarded as the most important factor especially among those in their 80s. The preferred top styles were T-shirts and blouses among those in their 60s and 70s, and T-shirts and shirts among those in their 80s. The preferred sleeve lengths were “below the elbow” and “above the wrist” in all age groups. The preferred sleeve hem type was “tightening” in all age groups. The most preferred bottom styles were “straight-leg pants” and “elastic waistband.” This study suggests the design items of indoor wear, including top, bottom, and overgarment for warmth, appropriate for elderly women at home based on the survey results. The study results are expected to serve as basic data necessary for the revitalization of the clothing industry for elderly women.
Flow-induced vibration can lead to fretting wear damage of fuel rods and spacer grids in nuclear reactors. Similarly, during the transport of spent nuclear fuel assemblies, continuous vibration and intermittent impact might also result in fretting wear due to dynamic interaction. Therefore, it is important to evaluate fuel rod damage due to fretting wear under such transport conditions. This study examines spent nuclear fuel rod specimens fabricated with hydride cladding tubes and simulated pellets, with hydrogen content ranging from 200 to 700 ppm and oxide film thickness ranging from 25 to 100 micrometers. Tests were conducted under a worst-case scenario, assuming continuous exposure to that condition during the expected transport time. Results indicate that the wear depth of all rod specimens occurred within the oxide film, suggesting a high resistance to fretting wear during transportation.
The intermediate shaft of sliding type is assembled with coated shaft joint and tube joint. Since the intermediate shaft plays a role of absorbing displacement change due to vibration, the intermediate shaft must have a sliding force value in an appropriate range. In this study, an intermediate shaft assembly system for post-processing of defective intermediate shafts was developed. The intermediate shaft assembly system consists of a wear count prediction model and an automatic wear system. A wear count prediction model was created with the initial assembly sliding force, quality, and set values. As a result of applying the intermediate shaft assembly device, the sliding force of the intermediate shaft was induced within the set value range. And it was prevented from the intermediate shaft defect and eliminated manual work.
This study aims to analyze research trends regarding outdoor wear. For this purpose, the data-collection period was limited to January 2002–October 2022, and the collection consisted of titles of papers, academic names, abstracts, and publication years from the Research Information Sharing Service (RISS). Frequency analysis was conducted on 227 papers in total to check academic journals and annual trends, and LDA topic-modeling analysis was conducted using 20,964 tokens. Data pre-processing was performed prior to topic-modeling analysis; after that, topic-modeling analysis, core topic derivation, and visualization were performed using a Python algorithm. A total of eight topics were obtained from the comprehensive analysis: experiential marketing and lifestyle, property and evaluation of outdoor wear, design and patterns of outdoor wear, outdoor-wear purchase behavior, color, designs and materials of outdoor wear, promotional strategies for outdoor wear, purchase intention and satisfaction depending on the brand image of outdoor wear, differences in outdoor wear preferences by consumer group. The results of topic-modeling analysis revealed that the topic, which includes a study on the design and material of outdoor wear and the pattern of jackets related to the overall shape, was the highest at 30.9% of the total topics. The next highest topic was also the design and color of outdoor wear, indicating that design-related research was the main research topic in outdoor wear research. It is hoped that analyzing outdoor wear research will help comprehend the research conducted thus far and reveal future directions.
The environment has increasingly attracted attention and fashion brands need to use new growth models by developing eco-friendly products, along with the drastic climate change. This study drew design guidelines from the factors of clothing disposal and reuse to propose ways to extend the longevity of clothing. It sets the design goals for the longevity extension of clothing as flexibility, originality, durability, and adjustability and drew a specific design guideline. The design methods used to achieve such goals are as follows. First, the design that is flexible in terms of physical changes needs to increase its activity and to be changeable, by applying pleats, rubber bands and elastic materials to the parts with many physical changes and movements. Second, it is necessary to reinforce the brand identity, create design that is flexible in terms of fashion and design very rare and attractive products, for the goal of original design beyond fashion. Third, it is necessary to increase the quality of clothing and improve the durability which can be decreased by washing and wearing. Fourth, it is necessary to create the design that can produce various styles, preserve the state of clothing and maintain its hygienic conditions by using removable detailed designs, shape-transformation designs and the designs which can be adjusted to climate changes and states, for the goal of adjustable design with better functionality. The findings provide ideas for fashion experts to pay more attention to the extending the longevity of clothing products and to develop eco-friendly designs and strategies.
본 연구는 골프웨어 브랜드 진정성과 브랜드 애착 및 충성도 간의 구조적인 모형을 검증하여 골프웨어의 브랜드 전략을 수립 할 수 있는 기초자료를 제공하고자 했다. 따라서 골프웨어를 구매했던 유 경험자를 표본으로 선정했으며, 292부의 자료를 최종분석에 활용했다. 자료처리 방법은 빈도분석과 신뢰도 의 내적일관성, 타당도의 확인적 요인분석, 상관분석, 그리고 구조방정식 모형분석을 실시했다. 프로그램은 SPSS(ver. 21.0)와 AMOS(ver. 20.0)를 활용했다. 연구결과 첫 번째로 골프웨어의 브랜드 진정성은 브랜드 애착에 유의한 영향을 미치는 것으로 나타났다. 둘째, 골프웨어의 브랜드 애착은 충성도에 유의한 영향을 미치는 것으로 나타났다. 셋째, 골프웨어의 브랜드 진정성은 충성도에 유의한 영향을 미치는 것으로 나타 났다. 마지막으로 골프웨어의 브랜드 진정성 및 충성도 간의 브랜드 애착은 부분매개효과가 있는 것으로 나타났다.
One of the most important problems in the cutting process of CFRP is tool wear. During CFRP machining, high temperature caused by friction between the cutting tool and the carbon fiber structure increase tool edge wear. Since CFRP is manufactured in a form in which the fibrous tissue is combined with a bonding resin, delamination caused by the separation of the resin and carbon fiber during process is recognized as a very big problem. This delamination proceeds very rapidly as the wear of the drill edge increases. Therefore, in this experiment, tool wear was measured during drilling using a TiAlN-coating drill with excellent wear resistance. In this study, tool wear is measured to suggest optimized cutting conditions for each material.
Although airborne wear particles (AWPs) generated from wheel-rail contacts are the major source of particulate matter (PM) in subway systems, studies on reducing the generation of such particles in order to enhance air quality are extremely rare. Therefore, this study investigated the effect of applying water-lubricant (applying tap water) on improving air quality by reducing the mass concentration (MC) of AWPs from wheel-rail contacts at a train velocity of 73 km/h using a twin-disk rig. An optical particle sizer was used to measure the MC of particles with the diameter range of 0.3 μm~10 μm. The results showed that the generation trends regarding PM1, PM2.5, and PM10 were different for dry and water-lubricated conditions: all three PMs showed an increasing-decreasing trend with slip rate under dry conditions; however, they were almost constant with slip rate under water-lubricated conditions. The particle size distributions were also different for dry and water-lubricated conditions: the peak occurred in multi-modal with the largest peak at approximately 6 μm in diameter under dry conditions; whereas, the peak occurred in bi-modal with the largest peak at approximately 0.9 μm in diameter under water-lubricated conditions. In addition, MCs were mostly smaller under water-lubricated conditions than dry conditions except at approximately 0.9 μm in diameter. Applying water significantly decreased PM1~2.5 and PM2.5~10 by more than 95%. This caused a decrease in PM2.5 and PM10 by 48.1% and 78.5%, respectively. On the other hand, applying water increased PM0.3~1 (i.e., PM1) by 52.8%, possibly owing to the effect of water vapor and mineral crystals from tap water. Overall, these findings indicate that water-lubrication can improve air quality in subway systems by reducing the MC of APWs generated from wheel-rail contacts. This study may provide a reference for future studies seeking to improve air quality in subway systems by reducing AWPs generated from wheel-rail contacts by applying lubricants.
목적 : OSDI 설문조사를 시행하여 소프트 콘택트렌즈 착용과 각막굴절교정수술 응답자 사이에서 안구건조 유병률을 비교하고자 하였다.
방법 : 대학생들을 대상으로 설문조사를 실시하였고, 또한 정시안을 대조군으로 사용하여 두 그룹을 비교하였다. 안구건조증은 OSDI 설문지를 이용하여 평가하였고, 안구건조증은 OSDI 점수에 따라 경도(13~22), 중등도 (23~32), 중증(33~100) 건성안으로 분류하였다.
결과 : 콘택트렌즈 착용에 62명, 굴절교정수술에는 49명, 대조군에 68명이 본 연구에 포함되었다. OSDI 점수는 두 그룹 모두 대조군 보다 높았으나 소프트 콘택트렌즈 착용과 굴절교정수술 사이에 안구건조 유병률은 통계적으로 차이가 없었다. 안구건조는 소프트 콘택트렌즈 착용자의 53.2% (n=33), 굴절교정 수술자의 53.1%(n=26), 대조군은 30.8%(n=21)로 나타났다.
결론 : 본 연구에서 소프트 콘택트렌즈 착용과 각막굴절교정수술 모두에서 안구건조증의 유병률은 50% 이상으로 대조군보다 높게 나타났고, 두 그룹의 안구건조 유병률은 거의 같게 나타났다.