• Title, Summary, Keyword: immersion test

Search Result 491, Processing Time 0.041 seconds

Comparison of Balance Ability according to the Immersion Level of Virtual Reality-based Training for the Balance Enhancement of the Elderly (노인의 균형증진을 위한 가상현실 기반 훈련의 몰입도에 따른 균형능력 비교)

  • Kim, Yeoung-Sung;Park, Min-Chull
    • PNF and Movement
    • /
    • v.16 no.2
    • /
    • pp.259-266
    • /
    • 2018
  • Purpose: This study aimed to compare balance ability according to the immersion level of virtual reality-based training for the balance enhancement of the elderly. Methods: This study included 48 elderly people aged 65 years and older (male 16, female 32). According to the immersion level of applied virtual reality training, 16, 17, and 15 persons were randomly assigned to full immersion, semi-immersion, and control groups. The subjects who were assigned to the full immersion group and semi-immersion group received virtual reality training for 6 weeks at 20 min at a time, 3 times per week. The control group received no intervention. Balance ability was evaluated by measuring the stability limit and the tandem walking test before and after the intervention. Results: Results showed significant differences among the three groups in the limit of stability of all directions and the tandem walking test after the intervention. The results of the limit of stability showed a significantly higher value in the full-immersion group than in the control group, and the results of the tandem walking test showed a significantly lower value in the full-immersion and semi-immersion groups than in the control group. Conclusion: The results indicate that the head-mounted display equipment for applying full-immersion virtual training is the most effective in enhancing the balance ability of the elderly.

A study on the corrosion characteristics of GMA and FS welded Aluminium alloy (알루미늄 합금 접합부의 부식 특성 연구)

  • 윤병현;노중석;김홍주;장웅성
    • Proceedings of the KWS Conference
    • /
    • /
    • pp.293-295
    • /
    • 2004
  • For the evaluation of corrosion resistance, Al 6061-T6 alloy was welded by Friction Sti. Welding(FSW) and Gas Metal Arc Welding(GMAW) evaluated by Tafel method and immersion test. The Tafel and immersion test results indicated that GMA weld was severely attacked compared with those of friction stir weld. It may be mainly due to the galvanic corrosion mechanism act on the CMA weld.

  • PDF

Critical Pitting Temperature of 2205 Duplex Stainless Steels Using Immersion and Electrochemical Polarization Test Methods (침지시험법 및 전기화학적 분극법에 의한 2205 이상 스테인리스강의 임계공식온도 측정 비교)

  • Shin Jae-Ho;Lee Jae-Bong
    • Journal of the Korean institute of surface engineering
    • /
    • v.39 no.1
    • /
    • pp.18-24
    • /
    • 2006
  • Although stainless steels have the excellent corrosion resistance by passive film, they are susceptible to pitting corrosion in the environment containing halogen elements such as chloride ions. The resistance to pitting corrosion can be evaluated by measuring the critical pitting temperature (CPT). CPT values can be obtained using immersion, potentiodynamic and potentiostatic polarization test methods. Results on duplex 2205 stainless steels showed that CPT values were measured as $50^{\circ}C,\;55^{\circ}C\;and\;61^{\circ}C$, respectively for immersion, potentiodynamic and potentiostatic polarization test methods, depending upon the different test methods, even though the difference between CPT values are not much.

A Study on Leaching Characteristics of Paraffin Waste Form Including Boric Acid

  • Kim, Ju-Youl;Chung, Chang-Hyun;Park, Heui-Joo;Kim, Chang-Lak
    • Nuclear Engineering and Technology
    • /
    • v.32 no.1
    • /
    • pp.10-16
    • /
    • 2000
  • Preliminary experiment was peformed to investigate the leaching characteristics of paraffin waste forms that had been recently generated in large quantities at domestic nuclear power plants. At first, waste simulants whose compositions were different in mixing ratio of paraffin to boric acid were prepared. Their compressive strengths were measured and ninety-day leaching test of specimen including cobalt was carried out according to ANSI/ANS-16.1 test procedure. Water immersion test was also conducted keeping pace with leaching test and the weight change and the compressive strength of specimen were observed after ninety days. The compressive strength of waste form exhibited 666 psi (4.53 MPa) in the case where mixing ratio of boric acid to paraffin was 78/22, which was adopted in concentrate waste drying system of domestic nuclear power plants. The leaching test resulted in about 50% of the cumulative fraction leached for boric acid and cobalt, respectively. The specific gravity of waste form was 0.87 [g/g]whose value was less than that of water because the weight loss of about 39% occurred after the water immersion test of ninety days. It was also observed that the waste form which had undergone ninety-day water immersion test exhibited the compressive strength of 203 psi (1.38 MPa).

  • PDF

A Study on Effects of AR and VR Assisted Lessons on Immersion in Learning and Academic Stress

  • Han, Ji-Woo
    • International Journal of Internet, Broadcasting and Communication
    • /
    • v.10 no.2
    • /
    • pp.19-24
    • /
    • 2018
  • This study investigated the academic stress and the immersion in learning in relation to AR and VR assisted instructions compared to traditional approaches. To that end, 78 $8^{th}$ graders in T and S city in Gangwondo were assigned to experimental and control groups. The experimental group received the VR and AR lessons. The academic stress was measured with the pre- and post-test scores, while the immersion in learning was measured with the post-test scores. In brief, AR and VR assisted lessons made statistically significant differences in the academic stress and immersion in learning in comparison to the traditional approaches.

Sulfate Resistance of Concrete using Ground Granulated Blast-furnace Slag for Recycling

  • Moon, Han-Young;Lee, Seung-Tae;Kim, Hong-Sam
    • Proceedings of the IEEK Conference
    • /
    • /
    • pp.508-513
    • /
    • 2001
  • Recently, ground granulated blast-furnace slag (GGBFS) has been increasingly used as additive for concrete. Many researchers reported that concrete using GGBFS had a better resistance under severe environments, such as marine or sulfate-rich soils, than Portland type cement concrete. The aim, therefore, of this study is to evaluate on the effectiveness of concrete using GGBFS when the concrete exposes to sulfate-rich environment. The detailed items for experiments show 2 series consisted of sulfate immersion test with mortar and sulfate diffusion test with concrete. The sulfate immersion test was performed for 400 days and contained reduction of compressive strength, length change and XRD analysis. For sulfate diffusion test, sulfate ions diffusivity was calculated on tile consideration of electrochemical theory by the diffusion cell test. As the results of this study, it was found that the concrete using GGBFS as additive was superior to portland type cement concrete. Consequently, the use of concrete with GGBFS for recycling may expect the durable and economical benefits.

  • PDF

Characterization of Emulsified Asphalt Emulsifier for Cold Recycling Asphalt Mixture (상온 재활용 아스팔트 혼합물용 유화 아스팔트 유화제 특성 분석)

  • Kim, Yeong Min;Choi, Hyun Joon;Ryu, Ju Yeol
    • International Journal of Highway Engineering
    • /
    • v.20 no.6
    • /
    • pp.151-161
    • /
    • 2018
  • PURPOSES : The purpose of this study is to examine the manufacturing method for emulsified asphalt and its bond performance by analyzing the properties of the emulsifier used to produce cold recycled asphalt mixtures. METHODS : In this study, four types of slow-setting cationic emulsifiers, a microsurfacing emulsifier, and six types of nonionic emulsifiers were used to manufacture emulsified asphalt. Because each emulsifier requires its own unique effective dose to provide the best performance, the optimum asphalt content for each effective dose was determined. Then, the optimum asphalt content for the emulsified asphalt mixture was determined by the tests to check its basic physical properties. By using the determined optimum content, asphalt mixtures were manufactured and dynamic immersion and tensile strength tests were conducted on the mixtures to analyze the influence of the emulsifier on the physical properties of the mixtures. RESULTS : The dynamic immersion test results showed a coating ratio of 54-85%, which is considerably higher than that of using ordinary straight asphalt. The tensile strength test yielded noncompliant values less than 0.4 N/mm, which is the standard requirement for dry indirect tensile strength. The correlation analysis between the dynamic immersion and tensile strength ratio tests showed very high correlation of 0.78. The correlation between the emulsifier content and water resistance performance was low, between -0.55 and -0.24. CONCLUSIONS : While the storage stability improves with increasing emulsifier, the effectiveness proportional to the increase is weaker as the emulsifier increases. The performance testing of asphalt residues before and after manufacturing the emulsified asphalt showed no significant change. It is proved that the emulsified asphalt maintains high coating resistance according to the dynamic immersion test results. In addition, according to the results of tensile strength ratio, cold recycled asphalt mixtures manufactured by the materials normally and commercially used are not compliant with the national standard specification; thus, additional effective materials will be needed for quality compliance. In conclusion, it is evident that the dynamic immersion and tensile strength ratio tests have good correlation, but the quantity of emulsifiers used is not related to the level of moisture resistance.

Durability Test on E-Glass Fiber Reinforced Composites of Strand Type in Specific Environment (스트란드형 유리섬유 강화 복합재료의 특수환경에 대한 내구성 시험)

  • Lee Seong-Ryul;Kim By-An;Moon Chang-Kwon
    • Journal of Ocean Engineering and Technology
    • /
    • v.20 no.2
    • /
    • pp.52-58
    • /
    • 2006
  • The effect of various environmental conditions on the durability of E-glass fiber/vinylester resin composites have been investigated using the tensile test specimen of strand type. It was found that the durability test method performed by the stand type specimen was more convenient and reliable than other conventional test method. The weight gains increased with the immersion time in both water and alkaline solution, and the Weight gains at $50^{\circ}C$. were much bigger than those at $20^{\circ}C$ in both conditions. The tensile strength decreased with the pass of immersion time in all aqueous solution, and the tensile strength at $80^{\circ}C$ in alkaline solution decreased very steeply at beginning of immersion time. The decrement of tensile strength according to the immersion time in various environmental conditions was mainly caused by the degradation of interface and the damage of glass fiber surface.

The Effects of Preschooler's Self-regulation and Maternal Parenting Behavior on Preschooler's Game Immersion (유아의 자기조절력과 어머니의 양육행동이 남녀 유아의 게임몰입성에 미치는 영향)

  • Kim, Kyoung-Hoe;Chung, Jee-Nha
    • Korean Journal of Human Ecology
    • /
    • v.23 no.2
    • /
    • pp.219-229
    • /
    • 2014
  • The purpose of this study was to investigate the effects of preschooler's self-regulation and maternal parenting behavior on preschooler's game immersion. Subjects were 253 4- to 5-year-old preschoolers(118 boys, 135 girls) and their mothers. Data were analyzed by descriptive statistics, t-test, correlation analysis and stepwise multiple regression analysis. The major findings are summarized as follows: (1) preschooler's game immersion differed from preschooler's gender. Boy preschooler had higher score than girl preschooler in game immersion. (2) Both boy and girl preschooler's game immersion was negatively correlated with preschooler's behavioral regulation and emotional regulation, maternal rational guidance, limit-setting and affection. (3) The most influential factor on boy preschooler's game immersion was behavioral regulation. On the other hand, the most influential factor on girl preschooler's game immersion was emotional regulation, and the next influential factor was maternal affection. Results of this study indicate that self-regulation enhancement program should be developed and mothers should be more affective with their preschoolers in order to prevent preschoolers' game immersion.

Effect of measurement method and cracking on chloride transport in concrete

  • Zhang, Shiping;Dong, Xiang;Jiang, Jinyang
    • Computers and Concrete
    • /
    • v.11 no.4
    • /
    • pp.305-316
    • /
    • 2013
  • This paper aims to study the effect of measurement methods and cracking on chloride transport of concrete materials. Three kinds of measurement methods were carried out, including immersion test, rapid migration test and steady-state migration test. All of these measurements of chloride transport show that chloride ion diffusion coefficient decreased with the reduction of water to cement ratio. Results of the immersion test were less than that of rapid migration test and steady-state migration test. For the specimen of lower water to cement ratio, the external electrical field has little effect on chloride binding relatively. Compared with the results obtained by these different measurement methods, the lower water to cement ratio may cause smaller differences among these different methods. The external voltage can reduce chloride binding of concrete, and the higher electrical field made a strong impact on the chloride binding. Considering the effect of high voltage on the specimen, results indicate that results based on the steady-state migration test should be more reasonable. For cracked concrete, cracking can accelerate the chloride ion diffusion.