• Title/Summary/Keyword: Volumetric Ratio

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Prognostic Implication of Volumetric Quantitative CT Analysis in Patients with COVID-19: A Multicenter Study in Daegu, Korea

  • Byunggeon Park;Jongmin Park;Jae-Kwang Lim;Kyung Min Shin;Jaehee Lee;Hyewon Seo;Yong Hoon Lee;Jun Heo;Won Kee, Lee;Jin Young Kim;Ki Beom Kim;Sungjun Moon;Sooyoung, Choi
    • Korean Journal of Radiology
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    • v.21 no.11
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    • pp.1256-1264
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    • 2020
  • Objective: Lung segmentation using volumetric quantitative computed tomography (CT) analysis may help predict outcomes of patients with coronavirus disease (COVID-19). The aim of this study was to investigate the relationship between CT volumetric quantitative analysis and prognosis in patients with COVID-19. Materials and Methods: CT images from patients diagnosed with COVID-19 from February 18 to April 15, 2020 were retrospectively analyzed. CT with a negative finding, failure of quantitative analysis, or poor image quality was excluded. CT volumetric quantitative analysis was performed by automated volumetric methods. Patients were stratified into two risk groups according to CURB-65: mild (score of 0-1) and severe (2-5) pneumonia. Outcomes were evaluated according to the critical event-free survival (CEFS). The critical events were defined as mechanical ventilator care, ICU admission, or death. Multivariable Cox proportional hazards analyses were used to evaluate the relationship between the variables and prognosis. Results: Eighty-two patients (mean age, 63.1 ± 14.5 years; 42 females) were included. In the total cohort, male sex (hazard ratio [HR], 9.264; 95% confidence interval [CI], 2.021-42.457; p = 0.004), C-reactive protein (CRP) (HR, 1.080 per mg/dL; 95% CI, 1.010-1.156; p = 0.025), and COVID-affected lung proportion (CALP) (HR, 1.067 per percentage; 95% CI, 1.033-1.101; p < 0.001) were significantly associated with CEFS. CRP (HR, 1.164 per mg/dL; 95% CI, 1.006-1.347; p = 0.041) was independently associated with CEFS in the mild pneumonia group (n = 54). Normally aerated lung proportion (NALP) (HR, 0.872 per percentage; 95% CI, 0.794-0.957; p = 0.004) and NALP volume (NALPV) (HR, 1.002 per mL; 95% CI, 1.000-1.004; p = 0.019) were associated with a lower risk of critical events in the severe pneumonia group (n = 28). Conclusion: CRP in the mild pneumonia group; NALP and NALPV in the severe pneumonia group; and sex, CRP, and CALP in the total cohort were independently associated with CEFS in patients with COVID-19.

Nitrogen Removal in the Multi-stage Bed Attached Growth Process of $A^2/O$ System with Interanal Recycle Ratio (다단층 부착성장 공법($A^2/O$향)에서 순환비에 따른 질소제거)

  • 최규철;윤용수;정일현
    • Journal of environmental and Sanitary engineering
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    • v.12 no.3
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    • pp.95-102
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    • 1997
  • The process which can stabilize water quality of treatment and improve nitrogen removal rate under the condition of high organic loading was developed by charging fibrous HBC media to single sludge nitrification-denitrification process. This process was operated easier, minimized the treatment cost, and shortened the retention time. To improve T-N removal rate, a part of nitrifing liquid at aerobic zone was recycled to anoxic zone by approximate internal recycle ratio. The experimental results are as follows ; T-N removal efficiency in the organic volumetric loading 0.14-0.19 kg/COD/m$^{3}$·d was obtained asmaxium of 85% at internal recycle ratio 2.5 and in more ratio than this it was decreased. Organic removal efficiency was about 91% under the overall experimental conditions and not influenced by recycle ratio.

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Ductility Evaluation of Heavyweight Concrete Shear Walls with Wire Ropes as a Lateral Reinforcement (와이어로프로 횡보강된 고중량콘크리트 전단벽의 연성평가)

  • Mun, Ju-Hyun;Yang, Keun-Hyeok
    • Journal of the Korea Concrete Institute
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    • v.27 no.3
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    • pp.207-214
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    • 2015
  • This study examined the feasibility of wire ropes as lateral reinforcement at the boundary element of heavyweight concrete shear walls. The spacing of the wire ropes varied from 60 mm to 120 mm at an interval of 30 mm, which produces the volumetric index of the lateral reinforcement of 0.126~0.234. The wire ropes were applied as a external hoop and/or internal cross-tie. Five shear wall specimens were tested to failure under constant axial load and cyclic lateral loads. Test results showed that with the increase of the volumetric index of the lateral reinforcement, the ductility of shear walls tended to increase, whereas the variation of flexural capacity of walls was minimal. The flexural capacity of shear walls tested was slightly higher than predictions determined from ACI 318-11 procedure. The displacement ductility ratio of shear walls with wire ropes was higher than that of shear wall with the conventional mild bar at the same the volumetric index of the lateral reinforcement. In particular, the shear walls with wire rope index of 0.233 achieved the curvature ductility ratio of more than 16 required for high-ductility design.

Continuous Bio-hydrogen Production from Food Waste and Waste Activated Sludge (음식물 쓰레기와 폐활성 슬러지를 이용한 생물학적 수소생산 및 수소생산 미생물 군집분석)

  • Kim, Dong-Kun;Lee, Yun-Jie;Kim, Dong-Im;Kim, Ji-Seong;Yu, Myong-Jin;Pak, Dae-Won;Kim, Mi-Sun;Sang, Byoung-In
    • KSBB Journal
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    • v.20 no.6
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    • pp.438-442
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    • 2005
  • Batch experiments were performed to investigate the effects of volumetric mixing ratio(v/v) of two substrates, food wastes(FW) and waste activated sludge(WAS). In batch experiments, optimum mixing ratio for hydrogen production was found at $10{\sim}20$ v/v % addition of WAS. CSTR(Continuous Stirred tank reactor) was operated to investigate the hydrogen productivity and the microbial community under various HRTs and volumetric mixing ratio(v/v) of two substrates. The maximum yield of specific hydrogen production, 140 mL/g VSS, was found at HRT of 2 day and the volumetric mixing ratio of 20:80(WAS:FW). The spatial distribution of hydrogen producing bacteria was observed in anaerobic fermentative reactor using fluorescent in situ hybridization(FISH) method.

Characteristic Behavior of High-Strength Reinforced Concrete Bridge Column under Simulated Seismic Loading (고강도 철근콘크리트 교각의 내진거동특성)

  • Ra Hong-Seong;Lee Kyoung-Joon;Ryu Hyo-Jin;Hwang Sun-Kyoung;Lee Chin-Ok
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.22-27
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    • 2004
  • This experimental investigation was conducted to examine the seismic performance of reinforced concrete bridge columns. The columns were subjected to a constant axial load and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement (ps = 0.96, 1.44 per cent) and axial load ratio (0.05, 0.1, 0.2 P/Po) and strength $(350kgf/cm^2,\;600kgf/cm^2)$. Test results show that bridge columns with 50 per cent higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour. For bridge columns with axial load ratio(P/Po) less than 0.2, the ratio of Mmax over Mad, nominal moment capacity predicted by ACI 318-02 provisions, is consistently greater than 1 with approximately a 20 percent margin of safty.

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An Experimental Study on Seismic Performance of Reinforced Concrete Bridge Columns under Lateral Cyclic Load (반복 횡하중을 받는 철근콘크리트 교각의 내진성능에 관한 실험적 연구)

  • 이진옥;윤현도;황선경;류효진;나홍성;이경준
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.161-164
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    • 2003
  • This experimental investigation was conducted to examine the seismic performance of reinforced concrete bridge columns. The columns were subjected to a constant axial load and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement ($P_s$ =0.96, 1.44 per cent) and axial load ratio (0.05, 0.1, 0.2 P/$P_o$). Test results show that bridge columns with 50 per cent higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour. For bridge columns with axial load ratio(P/$P_o$) less than 0.2, the ratio of $M_{max}$ over $M_{aci}$, nominal moment capacity predicted by ACI 318-02 provisions, is consistently greater than 1 with approximately a 20 percent margin of safty.

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Hysteric Behavior of Ultra-High Strength RC Columns (초고강도 RC 기둥의 이력특성에 관한 실험적 연구)

  • Kim Jong Keun;Ahn Jong Mun;Han Beom Seok;Shin Sung Woo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.31-34
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    • 2005
  • An experimental investigation was conducted to examine the hysteric behavior of Ultra-High strength concrete columns for the requirement of ACI provision. Seven 1/3 scaled columns were fabricated to simulate an 1/2 story of actual structural members with the cross section $300\times300mm$ and the shear span ratio 4. The main variables are axial load ratio, configuration and volumetric ratio of transverse reinforcement. It has been found that the behavior of columns was affected by axial load ratio rather than the amount and the configuration of transverse reinforcement. Consequently, to secure the ductile behavior of 100MPa Ultra-High strength concrete columns, ACI provision for the requirement of transverse steel may considered axial level and the detail of transverse reinforcement.

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Preparation of PVDF Hollow Fiber Membrane and Absorption of SO2 from Flue Gas Using Bench Scale Gas-Liquid Contactor (PVDF 중공사막 제조 및 벤치규모 기-액 접촉기를 이용한 SO2 흡수특성)

  • Park, Hyun-Hee;Jo, Hang-Dae;Kim, In-Won;Lee, Hyung-Keun
    • Korean Chemical Engineering Research
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    • v.46 no.3
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    • pp.521-528
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    • 2008
  • The micro-porous asymmetric PVDF hollow fiber membranes for gas-liquid contactor were prepared by the dry-jet wet phase inversion process and the characteristics of hollow fiber membranes were evaluated by the gas permeation method and scanning electron microscope. The chemical absorbent for removal of $SO_2$ gas was sodium hydroxide at bench scale hollow fiber membrane contactor. The experiments were performed in a counter-current mode of operation with gas in the shell side and liquid in the fiber lumen of the module to examine the effect of various operating variables such as concentration of absorbent, gas flow rate, L/G ratio and concentration of inlet $SO_2$ gas on the $SO_2$ removal efficiency using PVDF hollow fiber membrane contactor. Membrane mass transfer coefficient($k_m$) was calculated by mathematical modeling. The volumetric overall mass transfer coefficient increased with increasing the concentration of absorbent and L/G ratio. The increase of the absorbent concentration and L/G ratio not only provides more sufficient alkalinity but also decreases liquid phase resistance. The volumetric overall mass transfer coefficient increased with increasing gas flow rate due to decreasing the gas phase resistance.

Effect of Hydrophilic Polymer on Early Stages of Plant Growth of Euonymus fortunei 'Emerald and Gold' and Hedera japonica in a Vertical Greenery System for Low Maintenance (저관리 용기일체형 벽면녹화에서 황금줄사철과 송악의 초기활착에 미치는 친수성 중합체의 효용성)

  • Ju, Jin-Hee;Kim, Hea-Ran;Xu, Hui;Kim, Won-Tae;Choi, Eun-Young;Yoon, Yong-Han
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.19 no.3
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    • pp.1-9
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    • 2016
  • The objective of this study was to exam early stages of plant growth of Euonymus fortunei 'Emerald and Gold' and Hedera japonica grown in fabric felt bag attached on vertical greenery system with the ratio of hydrophilic polymer to substrate, 0(referred as Control), 0.1, 0.2, or 0.4% (v/v), in order to effectively utilize rainfall for low maintenance. After rainfall, the increase in volumetric water content of substrate amended with the hydrophilic polymer was between 13% and 87%, compared to that in Control. During drought period, higher ratio of hydrophilic polymer to substrate slowly decreased the volumetric water content, and increased plant height, leaf length, leaf width, number of leaves, branch number, and stem diameter of both Euonymus fortunei 'Emerald and Gold' and Hedera japonica with the highest fresh and dry weights of shoots or roots under the 0.1% ratio of hydrophilic polymer.

Nitrogen Removal from Wastewater by a Multi-stage Bio-reactor (다단 생물반응기에 의한 질소제거)

  • 최규철;정일현
    • Journal of environmental and Sanitary engineering
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    • v.13 no.1
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    • pp.91-103
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    • 1998
  • Design data for COD and nitrogen removal from wastewater were collected from Pilot's Multi-stage Bio-reactor. Hyraulic conditions and pollutant loadings were varied in order to optimize the biological and operational parameters. Pilot's experimental results summarize as followings. 1. T-N removal efficiency in the organic volumetric loading 0.2 kgCOD/m$^{3}$·d was obtained as maxium of 85% at internal recycle ratio 2.5 and in more ratio than this it was decreased. Organic removal efficiency was about 91% under the overall experimental conditions and not influenced by recycle ratio.. 2. Nitrification reaction was shown as maxium in the SCOD$_{cr}$/NH$^{+}$-N ratio of 6.5 and in more ratio than this it was decreased. Denitrification rate was the maxium as 85% in more than 7.5 of SCOD$_{cr}$/NO$_{x}$-N ratio and in the ratio over this ratio it becomes constant. 3. By utilizing an applied new model of Stover-Kincannon from Monod's kinetic model, concentration of T-N in the effluent according to flow quanity in the influent was estimated as 8.74 and -67.5 respectively. The formula for estimating T-N concentration of effluent was obtained like this: N$_e$=N$_0$(1- $\frac{8.74}{(QN$_0$/A)-67.05}$)

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