• Title/Summary/Keyword: Shoving

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Development of a Junction between Airport Concrete and Asphalt Pavements (공항 콘크리트와 아스팔트 포장 간의 접속 방법 개발)

  • Park, Hae Won;Kim, Dong Hyuk;Jeong, Jin Hoon
    • International Journal of Highway Engineering
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    • v.20 no.4
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    • pp.15-20
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    • 2018
  • PURPOSES : The purpose of this study is to analyze the magnitude of shoving of asphalt pavement by junction type between airport concrete and asphalt pavements, and to suggest a junction type to reduce shoving. METHODS : The actual pavement junction of a domestic airport, which is called airport "A" was modified by placing the bottom of the buried slab on the top surface of the subbase. A finite element model was developed that simulated three junction types: a standard section of junction proposed by the FAA (Federal Aviation Administration), an actual section of junction from airport "A" and a modified section of junction from airport "A". The vertical displacement of the asphalt surface caused by the horizontal displacement of the concrete pavement was investigated in the three types of junction. RESULTS : A vertical displacement of approximately 13 mm occurred for the FAA standard section under horizontal pushing of 100 mm, and a vertical displacement of approximately 55 mm occurred for the actual section of airport "A" under the same level of pushing. On the other hand, for the modified section from airport "A" a vertical displacement of approximately 17 mm occurred under the same level of pushing, which is slightly larger than the vertical displacement of the FAA standard section. CONCLUSIONS : It was confirmed that shoving of the asphalt pavement at the junction could be reduced by placing the bottom of the buried slab on the top surface of the subbase. It was also determined that the junction type suggested in this study was more advantageous than the FAA standard section because it resists faulting by the buried slab that is connected to the concrete pavement. Faulting of the junctions caused by aircraft loading will be compared by performing finite element analysis in the following study.

Performance of Constructed Facilities: Pavement Structural Evaluation of William P Hobby Airport in Houston, Texas

  • Kim, Sung-Hee;Jeong, Jin-Hoon;Kim, Nak-Seok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.1
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    • pp.21-25
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    • 2009
  • The results of a recent case study for material characterizations and structural evaluation to design asphalt overlay thickness of William P Hobby airport in Houston, Texas are presented herein. The existing runway 12R-30L of Hobby airport consisted of thick asphalt overlay over Portland Cement Concrete (PCC) and the localized surface shoving as evident in the closure of surface groove has been observed recently. Using the field cored asphalt concrete mixtures, measurements of percent air voids, asphalt content and aggregate gradation were conducted to find out the causations of surface shoving and groove closure. The FAA layered elastic program, LEDFAA was utilized to evaluate pavement structural conditions for new asphalt overlay. Two different composition assumptions for existing pavement were made to evaluate the pavement as followings: 1) APC, Asphalt Concrete Overlay over PCC pavement and 2) AC, Asphalt Concrete pavement. Based on laboratory testing results, a ratio of percent passing #200 to asphalt content ranged 1.1 to 2.2, which is considered a high ratio and a tendency of tender mix design was observed. Thus, the localized surface shoving and groove closure of the runway 12R-30L could be attributed to the use of excessive fine contents and tender mix design. Based on the structural evaluation results, it was ascertained that the analysis assuming the pavement structure as AC pavement gives more realistic structural life when the asphalt overlay is thicker enough compared to PCC layer because the existing PCC pavement under asphalt overlay acts more like a high quality base material.

An Effect of Clothing Purchasing Situation on Store Choice Behavior (의복구매상황에 따른 점포선택행동에 관한 연구 - 직업여성의 과제적 상황, 시간압박상황을 중심으로 -)

  • 원미향;박은주
    • Journal of the Korean Society of Clothing and Textiles
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    • v.18 no.2
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    • pp.234-243
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    • 1994
  • This research has studied situational effects on the perceived risk and store choice behavior. Data were obtained from 388 females with full-time jobs living in Pusan. The results analyzed by Spearman's rank correlation analysis, analysis of variance(ANOVA), 1-test and discriminant analysis. The results of this study were as follows; 1. There were significant differences in percieved risk according to the clothing purchasing situations. Performance risk was perceived high in gift-shopping situation and time-pressured situation, and financial risk was perceived high in self-shoving situation. 2. There were particularly significant differences in store attributes evaluation according to the clothing purchasing situations. In self-shopping situation, price, quality and reliability, store loyalty were evaluated as important store attributes. In gift-shopping situation, quality and reliability, product iuomation and in time-pressured situation, store loyalty and product information were evaluated as important store attributes. 3. Consumers preferred national brand franchise stores in self-shopping situation. They preferred department stores in gift-shopping situation and time-pressured situation. The types of selected store were mainly affetted by shopping convenience and location convenience.

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A Study on the Courtship Violence among Unmarried College Students I (미혼대학생의 혼전 단계에서의 신체적 폭력의 경험에 관한실태조사연구)

  • 김용미
    • Journal of Families and Better Life
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    • v.14 no.1
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    • pp.187-197
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    • 1996
  • The purpose of this study is to investigate the incidence and dynamics of permarital abuse among never-married college students. 21.3% of 497 male and female respondents reported that they had experienced premarital violence at least once. Types of violence most frequently used were pushing or shoving slapping and throwing objects. It is interesting that both victims and aggressors interpret violent acts as expression of love most of all. Behavioral response to violent acts were to try to make up to talk to the partner and to apologize. In general the respondents had negative attitudes toward violence in premarital and marital relationships. Males showed more positive attiutudes toward violence than females. This sex difference appeared to have some inflence on marital abuse, In is suggested that counseling program and shelter for victims of severe violence need to be developed.

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Effects of traffic characteristics on pavement responses at the road intersection

  • Yang, Qun;Dai, Jingwang
    • Structural Engineering and Mechanics
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    • v.47 no.4
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    • pp.531-544
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    • 2013
  • Compared with pavement structures of ordinary road sections, pavement structures in the intersection are exposed to more complex traffic characteristics which may exacerbates pavement distresses such as fatigue-cracking, shoving, shear deformation and rutting. Based on a field survey about traffic characteristics in the intersection conducted in Shanghai China, a three dimensional dynamic finite-element model was developed for evaluating the mechanistic responses in the pavement structures under different traffic characteristics, namely uniform speed, acceleration and deceleration. The results from this study indicated that : (1) traffic characteristics have significant effects on the distributions of the maximum principal strain (MPS) and the maximum shear stress (MSS) at the pavement surface; (2) vehicle acceleration or deceleration substantially impact the MPS and MSS at pavement surface and could increase the magnitude of them by 20 percent to 260 percent; (3) in the vertical direction, with the increase of vehicle deceleration rate, the location of the MPS peak value and the MSS peak value changes from the sub-surface layer to the pavement surface.

Tack Coat Inspection Using Unmanned Aerial Vehicle and Deep Learning

  • da Silva, Aida;Dai, Fei;Zhu, Zhenhua
    • International conference on construction engineering and project management
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    • 2022.06a
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    • pp.784-791
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    • 2022
  • Tack coat is a thin layer of asphalt between the existing pavement and asphalt overlay. During construction, insufficient tack coat layering can later cause surface defects such as slippage, shoving, and rutting. This paper proposed a method for tack coat inspection improvement using an unmanned aerial vehicle (UAV) and deep learning neural network for automatic non-uniform assessment of the applied tack coat area. In this method, the drone-captured images are exploited for assessment using a combination of Mask R-CNN and Grey Level Co-occurrence Matrix (GLCM). Mask R-CNN is utilized to detect the tack coat region and segment the region of interest from the surroundings. GLCM is used to analyze the texture of the segmented region and measure the uniformity and non-uniformity of the tack coat on the existing pavements. The results of the field experiment showed both the intersection over union of Mask R-CNN and the non-uniformity measured by GLCM were promising with respect to their accuracy. The proposed method is automatic and cost-efficient, which would be of value to state Departments of Transportation for better management of their work in pavement construction and rehabilitation.

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Binding Site of Spermine at Poly$[d(A-T)_2]$ and Poly$[d(G-C)_2]$ (Poly$[d(A-T)_2]$, Poly$[d(G-C)_2]$와 스퍼민의 결합 형태에 관한 연구)

  • Yun, Byeong Hwa;Jeon, Sun Hee;Song, Young Dae;Cho, Tae Sub;Kim, Seog K.
    • Journal of the Korean Chemical Society
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    • v.42 no.5
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    • pp.506-511
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    • 1998
  • When the spermine, which is one of the polyamines containing cation in vivo, binds to DNA, it can increase the stability of DNA. At the same time, it can cause B-form to Z-form transformations of DNA. However, because we cannot determine the binding geometry of the spermine to DNA by using spectroscopic methods, nobody can show the accurate binding mechanism of a DNA-spermine complex. Thus, we used DAPI as a spectroscopic probe of spermine, which binding geometry was well known. At the result of base selective binding geometry of spermine to synthetic DNA, the concentration of spermine gets higher, it grows the hydrophobic environment of DAPI which bound the minor groove of adenine-thymine base pair. Simultaneously, spermine seems to bridge the backbones around the minor groove of $poly[d(A-T)_2]$. So that, the intensity of fluorescence spectrum of that shows sudden increasement. In guanine-cytocine base pair, $poly[d(G-C)_2]$, we can suppose that spermine bind to the major groove of that, shoving out the DAPI which is partially intercalated between the base pocket across the major groove of it. In both cases, spermine doesn't show the base selectivity against to DNA.

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Assessing Studies on the Recent Use and Change of Indoor Landscaping Plants at Apartment Houses in Seoul (서울시내 아파트 실내조경식물이용의 최근변화에 관한 조사연구)

  • Kang, Hoon;Kwack, Beyoung-Hwa;Sim, Woo-Kyung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.18 no.1
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    • pp.1-8
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    • 1990
  • Forty different apartment houses were subjected to assess the status of indoor - landscaping plants found at each apartment house in Seoul for the year of 1986 and 7989. 1. Comparing with those of 1986, 46% increase in total indoor plant species and 68% increase in the number of them were observed. The most abundant sort found in 1786 was oriental orchid, African violet, Scindapsus, cacti, and Clivia, and in 1989, first with oriental orchid, cacti, Chlorophytum, Clivia and Dracaena, in that order. 2. Foliage ornamental plants were mast popularly found in both years of 1986 and 1989 when considered for horticultural classification of plants. 3. Average plant height ranged between 15 to 30 cm in the year of i986, whereas 31 to 80 cm in 1987, indicaling that the size of plants has greatly increased. 4. Kind of planters or containers was most frequently shown to be made of plastic material in both years, and the porcelain ones have significantly been increased to use recently. 5. Most indoor plants placed at the rooms were on the floor in those years, yet the use of planting shelves became particularly manifesting in the year of 1989. 6. Fittonia and cacti were the most frequently used plant materials for installing terrariums at apartment rooms In the year of 1986, whereas Adiantum and Maranta were so in 1989, indicating that the growers choose much adaptable species in apartment environments. Most of the plants grown to landscaping the indoors was apartment verandas in those years. 8. Average number of indoor plants possessed at each apartment houses surveyed for the year of 1986 was 16 different ones, whereas 27 each In 1789, shoving a noteworthy increase in the number. 9. There have been apparent increase and improvement inhabitant's indoor - plant interest in the years to pass and probably to come.

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