• Title/Summary/Keyword: open cut

Search Result 242, Processing Time 0.03 seconds

SUSTAINABILITY SOLUTIONS USING TRENCHLESS TECHNOLOGIES IN URBAN UNDERGROUND INFRASTRUCTURE DEVELOPMENT

  • Dae-Hyun (Dan) Koo;Samuel Ariaratnam
    • International conference on construction engineering and project management
    • /
    • 2013.01a
    • /
    • pp.367-374
    • /
    • 2013
  • Underground infrastructure systems provide essential public services and goods through buried structures including water and sewer, gas and petroleum, power and communication pipelines. The majority of existing underground infrastructure systems was installed in green field areas prior to development of complex urban built environments. Currently, there is a global trend to escalate major demand for underground infrastructure system renewal and new installation while minimizing disruption and maintaining functions of existing superstructures. Therefore, Engineers and utility owners are rigorously seeking technologies that minimize environmental, social, and economic impact during the renewal and installation process. Trenchless technologies have proven to be socially less disruptive, more environmentally friendly, energy conservative and economically viable alternative methods. All of those benefits are adequate to enhance overall sustainability. This paper describes effective sustainable solutions using trenchless technologies. Sustainability is assessed by a comparison between conventional open cut and trenchless technology methods. Sustainability analysis is based on a broad perspective combining the three main aspects of sustainability: economic; environmental; and social. Economic includes construction cost, benefit, and social cost analysis. Environmental includes emission estimation and environmental quality impact study. Social includes various social impacts on an urban area. This paper summarizes sustainable trenchless technology solutions and presents a sustainable construction method selection process in a proposed framework to be used in urban underground infrastructure capital improvement projects.

  • PDF

Radiofrequency in arthroscopic shoulder surgery: a systematic review

  • Neeraj Vij;Joseph N. Liu;Nirav Amin
    • Clinics in Shoulder and Elbow
    • /
    • v.26 no.4
    • /
    • pp.423-437
    • /
    • 2023
  • Background: Radiofrequency has seen an increase in use in orthopedics including cartilage lesion debridement in the hip and knee as well as many applications in arthroscopic shoulder surgery. The purpose of this systematic review is to evaluate the safety and usage of radiofrequency in the shoulder. Methods: This systematic review was registered with PROSPERO (international registry) and followed the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) guidelines. Embase and PubMed were searched using: "shoulder," "rotator cuff," "biceps," "acromion" AND "monopolar," "bipolar," "ablation," "coblation," and "radiofrequency ablation." The title and abstract review were performed independently. Any discrepancies were addressed through open discussion. Results: A total of 63 studies were included. Radiofrequency is currently utilized in impingement syndrome, fracture fixation, instability, nerve injury, adhesive capsulitis, postoperative stiffness, and rotator cuff disease. Adverse events, namely superficial burns, are limited to case reports and case series, with higher-level evidence demonstrating safe use when used below the temperature threshold. Bipolar radiofrequency may decrease operative time and decrease the cost per case. Conclusions: Shoulder radiofrequency has a wide scope of application in various shoulder pathologies. Shoulder radiofrequency is safe; however, requires practitioners to be cognizant of the potential for thermal burn injuries. Bipolar radiofrequency may represent a more efficacious and economic treatment modality. Safety precautions have been executed by institutions to cut down patient complications from shoulder radiofrequency. Future research is required to determine what measures can be taken to further minimize the risk of thermal burns.

Low-Pass Filter with Wide Stop-Band Characteristics Using Controllable Transmission Zeros (제어 가능한 전송 영점을 이용한 광대역 차단 특성을 갖는 저역 통과 필터)

  • Lee, Geon-Cheon;Kim, Yu-Seon;Kim, Kyung-Keun;Lee, Tae-Sung;Na, Hyeon-Sik;Lim, Yeong-Seog
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.18 no.8
    • /
    • pp.887-894
    • /
    • 2007
  • In this paper, design and fabrication of the LPF with controllable four transmission zeros using electric coupling and added open stub is presented. Pass-band of the LPF is GSM band, and two transmission zeros are generated by the electric coupling at the WiBro and S-DMB band, And the other two transmission zeros are generated by the open stub at the upper frequencies. Harmonic frequency of the stop-band is suppressed by the realization of the filter using quasi-lumped element with small parasitic values. $C_M$, which is the electric coupling element of the equivalent circuit, is realized by the distance control between the open stubs of the filter structure. The fabricated LPF used teflon substrate with relative permittivity of 2.6. And it has a size of $38{\times}20{\times}0.79 mm^3$, which is including a feed line. The measured 3 dB cut-off frequency is 1.55 GHz, and locations of the transmission zeros are 2.20, 2.43, 4.11 and 6.84 GHz, respectively.

THE EFFECT OF SANDWICH TECHNIQUE USING FLOWABLE COMPOSITE RESIN BASE ON THE MICROLEAKAGEIN CLASS II CAVITIES OF MOLAR (구치부 제2급 와동에서 고흐름성 복합레진을 이용한 적층 충전술식의 미세누출에 미치는 영향)

  • Lee, Kang;Hong, Chan-Ui
    • Restorative Dentistry and Endodontics
    • /
    • v.27 no.5
    • /
    • pp.502-514
    • /
    • 2002
  • The aim of this study was to evaluate the marginal adaptation of direct class II sandwich restoration with packable composites(P-60), resin modified glass ionomer cement(Fuji-II LC), flowable compomer(Dyract Flow), flowable composites(Filtek Flow) in comparison with total bond restorations. In addition, for sandwich restorations, influence of different sandwich techniques was also evaluated. Large butt-joint box typed class II cavites with cervical margins 1mm below the cemento-enamel junction were cut into 70 extracted human molars. The cavities(7 groups, n=10) were filled using a closed/open sandwich restoration or total bond restoration technique with materials according to the manufacturer's recommandation using the single-component bonding agent for each system. Teeth were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 30-second dwell time. The teeth were then coated with nail polish 1mm short of the restoration, placed in a 2% methylene blue for 24 hours, and sectioned with diamond wheel. Sections were examined with a stereoscope to determine the extent of microleakage. Dentine /Cementum margins were analyzed for microleakage on scale of 0(no leakage) to 4(entire axial wall) and interface between materials, on scale of 0(no leakage) to 3(axial wall). Results were evaluated with Kruskal Wallis Test, corrected for ties, to determine whether there were statistically significant differences among the seven groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Dunn s Method. The results were as follows : 1. All groups showed some micoleakage in cervical portion. But there were no microleakage in interface between materials. 2. Closed sandwich restorations with Fuji-II LC and Filtek Flow had significantly lower leakage rating than total restorations with only P-60. However, open sandwich restorations with Dyract Flow showed significantly higher (P<0.05) 3. Closed sandwich restorations had significantly lower leakage rating than total restorations. However open sandwich restoration s showed significantly higher (P<0.05). 4. Sandwich restorations with Fuji-II LC were iou$.$or leakage than only P-60. Filtek Flow, Dyract Flow. But there were no statistically differences among the materials. From the results above, it could be concluded, closed sandwich restorations was effective in reducing microleakage of class II restorations. The best results showing the least microleakage were for the closed sandwich technique with Fuji-II LC and Filtek Flow.

Process Optimization for Concentration and Stabilization of Recombinant Endoxylanase Expressed in Bacillus subtilis (Bacillus subtilis에서 발현된 재조합 Endoxylanase 농축과 안정화 공정의 최적화)

  • Choe, Yeong-Rok;Park, Jeong-Ha;;Kim, Yeong-Man;Gwon, Hyeon-Ju;Kim, Byeong-U
    • Microbiology and Biotechnology Letters
    • /
    • v.32 no.4
    • /
    • pp.322-327
    • /
    • 2004
  • A strong constitutive PJH promoter from Bacillus sp. was applied to overexpress the endoxylanase gene (639 bp) in Bacillus subtilis. The expression plasmid, pJHKJ4, was designed to contain the $P_{JH}$ promoter and open reading frame of endoxylanase including its own promoter. The plasmid was introduced into B. subtilis DB431 and the resulting transformant was grown on LB glucose medium. At the end of cultivation, the endoxylanase activity in the culture supernatant reached about 140 DIm!. The enzyme in the supernatant was concentrated by ultrafiltration (MW cut-off 10 kDa and 30 kDa) and ammonium sulfate precipitation. For the concentration of the enzyme, ultrafiltration was more efficient than 70% ammonium sulfate precipitation. The stabilization of concentrated enzyme solution at $50^{\circ}C$ was examined with various stabilizers such as NaCI, glycerol, polyethylene glycol, sorbitol, and $CaCI_2$. The most effective stabilizers were found to be NaCI and $CaCI_2$.

Initial Development of Forest Structure and Understory Vegetation after Clear-cut in Pinus densiflora Forest in Southern Gangwon-do Province (강원도 남부 지역에서 소나무림 개벌 후 초기 임분 구조 및 하층식생 발달)

  • Bae, Kwan Ho;Kim, Jun Soo;Lee, Change Seok;Cho, Hyun Je;Lee, Ho Young;Cho, Yong Chan
    • Journal of Korean Society of Forest Science
    • /
    • v.103 no.1
    • /
    • pp.23-29
    • /
    • 2014
  • Open- to closed canopy stage and it's ecological characteristics in vegetation succession are commonly described, but poorly understood in Korea. Vegetation development on structure, environment and understory abundance were studied for 16 yr in post-clearcut Pinus densiflora forests in the southern Gangwon-do province by applying space-for-time approach. We sampled 210 plots (10 for structure and 200 for understory) for four seral stages (1yr, 3yr, 10yr and 16yr). After clear-cut, mean stem density increased gradually to $5,714{\pm}645$ stems/ha after 16 years and mean basal area was also from $5.5{\pm}0.7m^2/ha$ after 10 years and doubled at $10.0{\pm}1.6m^2/ha$ in 16 years. Woody debris and bared soil on the forest floor peaked at 11--- after 10 years and at 10.3--- after 3 years, respectively. In understory mean cover declined with all growth form groups following succession, but in richness, forb specie increased with structural development during 16 years. Our study suggested that overstory development did not suppressed whole understory properties especially in richness, thus appeared to act as a filter selectively constraining the understory characteristics. However only long-term studies are essential for elucidating patterns and processes that cannot be inferred form short-term or space-for-time researches. Strong negative relationship between overstory and understory characteristics in conventional models surely reexamined.

The Effects of Artificial Dead Space on the Pulmonary Ventilation of Intubated Children with Mechanical Ventilation (기관 삽관후 인공호흡기를 적용한 개심술 환아의 인공기도 체외 용적이 폐환기 상태에 미치는 영향)

  • 유정숙;윤선희;송계희;민열하
    • Journal of Korean Academy of Nursing
    • /
    • v.31 no.1
    • /
    • pp.31-42
    • /
    • 2001
  • This study was done to evaluate the effect reducing artificial dead space on intubated children. Data were collected from July 1st, 1998 to August 31st, 1999. The subjects were selected from a pediatric intensive care unit of 'S' hospital and intubated with 3.5 mm or 4.5 mm endotracheal tube after open heart surgery. They were composed of 34 patients : 17 patients were assigned to the experimental group and the rest of them were placed in the control group. The artificial airway volume was minimized in the experimental group, and the control group maintained the artificial airway volume. ETCO2, PaCO2, SPO2 were measured as indicators of pulmonary ventilation. The tools of this study were GEM-Premier and Space-Lab patient monitors. The data were analyzed using the SPSS/PC+ program. The $\chi$2 -test was used to find general characteristics. The t-test was used to test the homogenety of the pulmonary ventilation status and mechanical ventilation setting before intervention between the two groups. Also, the paired t-test was used to examine the hypothesis. The results can be summerized as : 1. CO2 can be expelled effectively from the body in case artificial dead space was decreased. 2. As the artificial dead space was reduced, the difference between ETCO2 and PaCO2 was decreased, in other words pulmonary ventilation was improved. 3. If the artificial dead space occupied above 15 percent of tidal volume, the effect of CO2 was retention revealed in the body. 4. If the artificial dead space occupied below effect. Based on the results, the following is suggested to be applied practically : 1. A kind of the ventilator circuit acting artificial dead space should be removed from the intubated children with mechanical ventilaion. 2. The endotracheal tube should not be cut because extra-body space of the endotracheal tube did not have an effect on the dead space of the intubated children. Since the researcher could not cover this aspect in the study, they recommend the following. 1. The study should be extended to the other pulmonary disease patients for the effect of improving pulmonary ventilation. 2. Also, further studying with a more narrow interval in the extra-body space of the artificial airway will be able to explain the point of artificial dead space with proper ventilation.

  • PDF

Changes in Blood Glucose and Electrolyte During Open Heart Surgery (저체온 개심술시 혈당 및 전해질치의 변화에 관한 연구)

  • Yoo, Byeung-Lyeul;Kim, Heung-Dae;Lee, Tae-Sook
    • Journal of Yeungnam Medical Science
    • /
    • v.4 no.1
    • /
    • pp.65-74
    • /
    • 1987
  • This study deals with the changes in the concentrations of blood glucose and electrolytes during open heart surgery. Blood glucose and electrolytes in connection with age, disease and anesthetic period were measured in 25 patients about to undergo heart surgery which were performed between June 1986 and August 1986 in Yeungnam University Hospital. Because glucose solution is commonly used as priming solution, and the priming solution is hyperglycemic and hyperosmolar, glucose level of priming solution in this study was adjusted to 100-200mg% level to minimize hyperglycemic and hyperosmolar effect. The following results were obtained. 1. Glucose level of priming solution before extracorporeal circulation was $151.6{\pm}3.13mg%$. 2. With body cooling, blood glucose level was elevated. As duration of extracorporeal circulation is prolonged, blood glucose level was elevated more, but no difference between age and diseases were observed. On warming, blood glucose level was progressively lowered. 3. Despite the low serum potassium level during by pass, the potassium level was progressively elevated following by-pass, cut the serum potassium level was low compared to control values. Elevated calcium level was maintained during by pass.

  • PDF

'Dream Song', a New Cultivar of Gypsophila paniculata with Traits of Simultaneous Blooming and Narrow Branching Angle (분지각이 작고 일시 개화성이 우수한 숙근 안개초 '드림송' 육성)

  • Cheong, Dong-Chun;Choi, Chang-Hak;Song, Young-Ju;Kim, Jeong-Man;Lee, Jin-Je
    • Horticultural Science & Technology
    • /
    • v.32 no.4
    • /
    • pp.571-575
    • /
    • 2014
  • 'Dream Song' is a cultivar of Gypsophila paniculata developed by the Jeollabuk-do Agricultural Research & Extension Services in 2010 for cut-flower production. This hybrid was bred from 121 seedlings collected from an open-pollinated population of 'Gyp06-11'. It has novel morphological characteristics of upright plant type, lanceolate leaves, double florets with a few bright white-colored petals of obovate shape, truncate petal tips, and cup-shaped calyces. Furthermore 'Dream Song' has desirable cultivation characteristics including narrow branching angle, and moderate resistance to powdery mildew, thrips and leaf miners. Moreover it produces more primary branches, and longer internodes and flower stalks than reference cultivar 'Bristol Fairy' during summer cultivation in a subalpine area (500 m over the sea level). Flowering in 'Dream Song' is delayed by about 17 days as compared to 'Bristol Fairy'. 'Dream Song' produces normal flowers with 2 pistils and an average of 10.4 stamens, with fewer malformed flowers than 'Bristol Fairy'.

A New Spray Chrysanthemum Cultivar, "Water Fog" with Single Type and White Petals for Cut Flower (절화용 백색 흩꽃 스프레이국화 "워트포그" 육성)

  • Hwang, Ju-Chean;Chin, Young-Don;Chung, Yong-Mo;Kim, Su-Gyeong
    • Korean Journal of Breeding Science
    • /
    • v.40 no.2
    • /
    • pp.159-163
    • /
    • 2008
  • A New spary chrysanthemum (Dendranthema grandiflorum) cultivar 'Water Fog' was bred by open pollination of 'Angaesoguk'. Its characteristics were investigated three times from 2004 to 2006 under forcing culture in spring and retarding culture in autumn. The natural flowering time of 'Water Fog' was 24 October, but year-round production was possible by shading and lighting. It had flower diameter of 2.3 cm, 46.5 petals and 34.4 flowers per stem in autumn. The petal was narrow(0.4cm) and the color of petal was white with presence of green at flower center. Days to flower from short-day start for 'Water Fog' was about 48 in spring. 'Water Fog' showed the vase life of 22.6 days in autumn. This cultivar was registered for a commercialization in 2007. 'Water Fog' would be cultured under greenhouse and rain shelter condition in Korea.