• Title/Summary/Keyword: 3D(3-Dimensional) data

Search Result 1,584, Processing Time 0.025 seconds

Computational Fluid Dynamics(CFD) Simulation for a Pilot-scale Selective Non-catalytic Reduction(SNCR) Process Using Urea Solution (요소용액을 이용한 파일럿규모 SNCR 공정에 대한 CFD 모델링 및 모사)

  • Nguyen, Thanh D.B.;Kang, Tae-Ho;Lim, Young-Il;Kim, Seong-Joon;Eom, Won-Hyeon;Yoo, Kyung-Seun
    • Korean Chemical Engineering Research
    • /
    • v.46 no.5
    • /
    • pp.922-930
    • /
    • 2008
  • The selective non-catalytic reduction(SNCR) performance is sensitive to the process parameters such as flow velocity, reaction temperature and mixing of reagent(ammonia or urea) with the flue gases. Therefore, the knowledge of the velocity field, temperature field and species concentration distribution is crucial for the design and operation of an effective SNCR injection system. In this work, a full-scale two-dimensional computational fluid dynamics(CFD)-based reacting model involving a droplet model is built and validated with the data obtained from a pilot-scale urea-based SNCR reactor installed with a 150 kW LPG burner. The kinetic mechanism with seven reactions for nitrogen oxides($NO_x$) reduction by urea-water solution is used to predict $NO_x$ reduction and ammonia slip. Using the turbulent reacting flow CFD model involving the discrete droplet phase, the CFD simulation results show maximum 20% difference from the experimental data for NO reduction. For $NH_3$ slip, the simulation results have a similar tendency with the experimental data with regard to the temperature and the normalized stoichiometric ratio(NSR).

Thermal Elasto-Plastic Deformation Analysis of Metal Matrix Composites Considering Residual Stress and Interface Bonding Strength (잔류응력과 계면접합강도를 고려한 금속복합재료의 열탄소성 변형 해석)

  • Kang, Chung-Gil;Seo, Young-Ho
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.16 no.1 s.94
    • /
    • pp.227-237
    • /
    • 1999
  • As the interface bonding phenomenon between the matrix and the reinforcements has a large effect on the mechanical properties of MMCs, a sugestion of the strength analysis technique considering the residual stress and the interface bonding phenomenon is very important for the design of pans and the estimation of fatigue behavior. In this paper the three dimensional finite element anaysis is performed during the elasto-plastic deformation of the particulate reinforced metal matrix composites. It was analyzed with the volume fractions in view of microscale. Bonding strength. interface separation and matrix void growth between the matrix and the reinforcements will be predicted on deformation under tensile loading. An interface seperation is estimated by the fracture criterion which is a critical value of generalized plastic work per unit volume. The shape of the reinforcement is assumed to be a perfect sphere. And the type of the reinforcement distribution is assumed as FCC array. The thermal residual stress in MMCs is induced by the heat treatment. It is included at the simulation as an initial residual stress. The element birth and death method of the ANSYS program is used for the estimation of the interface bonding strength, void generation and propagation. It is assumed that the fracture in the matrix region begin to occur under the external loading when the plastic work per unit volume is equal to the critical value. The fracture strain will be defined. The experimental data of the extruded $SiC_p$>/606l Al composites are compared with the theoretical results.

  • PDF

Hemodynamic Characteristics Affecting Restenosis after Percutaneous Transluminal Coronary Angioplasty with Stenting in the Angulated Coronary Stenosis

  • Lee, Byoung-Kwon;Kwon, Hyuck-Moon;Roh, Hyung-Woon;Cho, Min-Tae;Suh, Sang-Ho
    • International Journal of Vascular Biomedical Engineering
    • /
    • v.1 no.1
    • /
    • pp.13-23
    • /
    • 2003
  • Backgrounds: The present study in angulated coronary stenosis was to evaluate the influence of velocity and wall shear stress (WSS) on coronary atherosclerosis, the changes of hemodynamic indices following coronary stenting, as well as their effect of evolving in-stent restenosis using human in vivo hemodynamic parameters and computed simulation quantitatively and qualitatively. Methods: Initial and follow-up coronary angiographies in the patients with angulated coronary stenosis were performed (n=80). Optimal coronary stenting in angulated coronary stenosis had two models: < 50 % angle changed(model 1, n=43), > 50% angle changed group (model 2, n=37) according to percent change of vascular angle between pre- and post-intracoronary stenting. Flow-velocity wave obtained from in vivo intracoronary Doppler study data was used for in vitro numerical simulation. Spatial and temporal patterns of velocity vector and recirculation area were drawn throughout the selected segment of coronary models. WSS of pre/post-intracoronary stenting were calculated from three-dimensional computer simulation. Results: Follow-up coronary angiogram demonstrated significant difference in the percent of diameter stenosis between two groups (group 1: $40.3{\pm}30.2$ vs. group 2: $25.5{\pm}22.5%$, p<0.05). Negative WSS area on 3D simulation, which is consistent with re-circulation area of velocity vector, was noted on the inner wall of post-stenotic area before stenting. The negative WSS was disappeared after stenting. High spatial and temporal WSS before stenting fell into within physiologic WSS after stenting. This finding was prominent in Model 2 (p<0.01) Conclusions: The present study suggests that hemodynamic forces exerted by pulsatile coronary circulation termed as WSS might affect on the evolution of atherosclerosis within the angulated vascular curvature. Moreover, geometric change, such as angular difference between pre / post-intracoronary stenting might give proper information of optimal hemodynamic charateristics for vascular repair after stenting.

  • PDF

Analyses of Dipole-Dipole IP Responses over Dipping Structures (경사구조에 대한 쌍극자 IP 응답의 해석)

  • Kim, Hee Joon
    • Economic and Environmental Geology
    • /
    • v.17 no.1
    • /
    • pp.49-55
    • /
    • 1984
  • This paper describes three-dimensional (3-D) standard curves for conductive dipping buried bodies in induced polarization (IP) method. Dipole-dipole IP responses for the dipping bodies are calculated by the numerical modeling technique using an integral equation solution. Dip angles of the bodies are 0, 20, 45, 70 and 90 degrees, respectively. The horizontal (0-degree dip) and vertical (90-degree dip) bodies produce symmetrical patterns of IP responses. The dipping bodies of 20, 45 and 70 degrees, however, produce asymmertical patterns, with the highest IP contours dipping in the direction opposite to the bodies in pseudo-sections. The most remarkable asymmetrical pattern appears in the model of 20-degree dip. It is difficult to distinguish the body of 70-degree dip from that of 90-degree dip on the basis of dipole-dipole IP data. The IP pattern in pseudo-sections varies when the line moves away from the center of the body along strike, with the anomaly deeper and smaller in amplitude. IP maps seem to be more useful than IP pseudo-sections in predicting the location of target.

  • PDF

Design and Implementation of μ-Webpage based on QR Code (QR 코드 기반 마이크로 웹페이지 설계 및 구현)

  • Ha, Sunju;Eun, Seongbae;So, SeonSub;Yun, Young-Sun;Jung, Jinman
    • KIISE Transactions on Computing Practices
    • /
    • v.21 no.3
    • /
    • pp.239-246
    • /
    • 2015
  • QR(Quick Response) Code has been developed to provide greater storage capacity and more functionality compared to 1D bar codes. With the emergence of increasingly mobile devices equipped with cameras such as smart-phones and tablets, QR codes have become very popular and more important in mobile businesses. Typically, most QR codes are used as a URL link for redirecting users to webpages. However, the URL based QR codes are required to be connected over the internet and to be run a server. This can incur unnecessary traffics in the Internet. Furthermore, it is not suitable for the country lagging behind others in its network infrastructure. In this paper, we propose a server-less ${\mu}$-webpage to provide mobile web services and be optimized for the capabilities and limitations of QR Code. We have implemented the ${\mu}$-webpage in Android, and the results showed that the proposed mechanism can provide web-services without requiring extra servers or incurring mobile traffic data compared to the URL-based QR Codes.

Analysis the Effects of Physical Blocking Weirs on the Water Quality in Daechung Reservoir (물리적 차단시설이 대청호 수질에 미치는 효과 분석)

  • Lee, Heungsoo;Chung, Sewoong;Park, Hyungseok;Jeong, Donghwan
    • Journal of Environmental Impact Assessment
    • /
    • v.21 no.1
    • /
    • pp.25-39
    • /
    • 2012
  • This study was aimed to assess the effects of additional installation of two different types of weirs, one is a curtain-type weir and another is a submerged-type weir, on the control of algal growth in Daechung Reservoir. A two-dimensional(2D) coupled hydrodynamic and eutrophication model that can accommodate vertical movement of the curtain weir following the water surface variations was verified using field data obtained in two distinctive hydrological years; dry(2008) and wet(2010). The model adequately simulated the temporal and spatial variations of water temperature, nutrients and algal(Chl-a) concentrations during the periods. The effectiveness of curtain weir on the control of algal bloom was evaluated by applying the model to 2001(dry year) and 2010 assuming 6 different scenarios according to installation locations. The curtain weirs that already installed at 3, 5, 7 sites(scenario C-2) showed significant effect on the control of algal growth in the reservoir; the reduction rates of algal concentration were placed in the range of 7.5~31.5% and 9.1~44.9% for 2001 and 2010, respectively. However the simulation results revealed that additional installation of curtain weirs(scenario C-3~C-6) in the bay area (choosori) have marginal effect. The effectiveness of submerged weir was evaluated against 2010 assuming 7 different scenarios according to installation locations, but all scenarios(S-1~S-7) showed neglectable or negative effect on the control of algal growth.

Dual Mode Feedback-Controlled Cycling System for Upper Limb Rehabilitation of Children with Cerebral Palsy

  • Cho, Seung-Yeon;Kim, Jihun;Seo, Seong-Won;Kim, Sung-Gyung;Kim, Jaehyo
    • International Journal of Advanced Culture Technology
    • /
    • v.7 no.1
    • /
    • pp.231-236
    • /
    • 2019
  • Background/Objectives: This paper proposes a dual mode feedback-controlled cycling system for children with spastic cerebral palsy to rehabilitate upper extremities. Repetitive upper limb exercise in this therapy aims to both reduce and analyze the abnormal torque patterns of arm movements in three- dimensional space. Methods/Statistical analysis: We designed an exercycle robot which consists of a BLDC motor, a torque sensor, a bevel gear and bearings. Mechanical structures are customized for children of age between 7~13 years old and induces reaching and pulling task in a symmetric circulation. The shafts and external frames were designed and printed using 3D printer. While the child performs active/passive exercise, angular position, angular velocity, and relative torque of the pedal shaft are measured and displayed in real time. Findings: Experiment was designed to observe the features of a cerebral palsy child's exercise. Two children with bilateral spastic cerebral palsy participated in the experiment and conducted an active exercise at normal speed for 3 sets, 15 seconds for each. As the pedal reached 90 degrees and 270 degrees, the subject showed minimum torque, in which the child showed difficulty in the pulling task of the cycle. The passive exercise assisted the child to maintain a relatively constant torque while visually observing the movement patterns. Using two types of exercise enabled the child to overcome the abnormal torque measured in the active data by performing the passive exercise. Thus, this system has advantage not only in allowing the child to perform the difficult task, which may contribute in improving the muscle strength and endurance and reducing the spasticity but also provide customizable system according to the child's motion characteristic. Improvements/Applications: Further study is needed to observe how passive exercise influences the movement characteristics of an active motion and how customized experiment settings can optimize the effect of pediatric rehabilitation for spastic cerebral palsy.

Conservation Treatment and the Development of a Relics Filling Pad to Maintain the Shape of a Doctor's Coat Worn by Seo Jae-pil, the National Registered Cultural Heritage No. 607 (국가등록문화재 제607호 서재필 진료가운 보존처리와 유물 충전재 개발)

  • Lee, Ryangmi;An, Boyeon;Jun, Eunjin
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.45 no.3
    • /
    • pp.409-422
    • /
    • 2021
  • A doctor's coat worn by Seo Jae-pil (1864-1951)-National Registered Cultural Heritage No. 607-was conserved with wet cleaning to remove thick wrinkles and brown stains that had been present for a long time. This paper also applied microscopic observation and infrared spectrophotometric analysis to obtain scientific investigation data on the cotton fabric of this doctor's coat. Information about Seo Jae-pil's time as a doctor, the process of changing his English name, and C.D.Williams & Co., which produced the medical coat, revealed that this doctor's coat was worn by Seo Jae-pil between 1892 and 1898 or 1926 and 1939. Additionally, this paper proposes a pad for filling relics that can protect the shape of modern and contemporary clothing, such as Seo Jae-pil's doctor's coat, for display at a museum site. Specifically, this research provides detailed information on the manufacturing of filling pads that can prevent damage to modern and contemporary jackets and coats so that they can be used in the cultural heritage field by developing filling materials for three-dimensional costume artifacts.

Reconstruction of Pharyngolaryngeal Defects with the Ileocolon Free Flap: A Comprehensive Review and How to Optimize Outcomes

  • Escandon, Joseph M.;Santamaria, Eric;Prieto, Peter A.;Duarte-Bateman, Daniela;Ciudad, Pedro;Pencek, Megan;Langstein, Howard N.;Chen, Hung-Chi;Manrique, Oscar J.
    • Archives of Plastic Surgery
    • /
    • v.49 no.3
    • /
    • pp.378-396
    • /
    • 2022
  • Several reconstructive methods have been reported to restore the continuity of the aerodigestive tract following resection of pharyngeal and hypopharyngeal cancers. However, high complication rates have been reported after voice prosthesis insertion. In this setting, the ileocolon free flap (ICFF) offers a tubularized flap for reconstruction of the hypopharynx while providing a natural phonation tube. Herein, we systematically reviewed the current evidence on the use of the ICFF for reconstruction of the aerodigestive tract. A systematic literature search was conducted across PubMed MEDLINE, Web of Science, ScienceDirect, Scopus, and Ovid MEDLINE(R). Data on the technical considerations and surgical and functional outcomes were extracted. Twenty-one studies were included. The mean age and follow-up were 54.65 years and 24.72 months, respectively. An isoperistaltic or antiperistaltic standard ICFF, patch flap, or chimeric seromuscular-ICFF can be used depending on the patients' needs. The seromuscular chimeric flap is useful to augment the closure of the distal anastomotic site. The maximum phonation time, frequency, and sound pressure level (dB) were higher with ileal segments of 7 to 15 cm. The incidence of postoperative leakage ranged from 0 to 13.3%, and the majority was occurring at the coloesophageal junction. The revision rate of the microanastomosis ranged from 0 to 16.6%. The ICFF provides a reliable and versatile alternative for reconstruction of middle-size defects of the aerodigestive tract. Its three-dimensional configuration and functional anatomy encourage early speech and deglutition without a prosthetic valve and minimal donor-site morbidity.

Understanding the Technical Properties of Delonix regia (HOOK.) RAF. Wood: A Lesser Used Wood Species

  • Funke Grace Adebawo;Olayiwola Olaleye Ajala;Olaoluwa Adeniyi Adegoke;Timileyin Samuel Aderemi
    • Journal of Forest and Environmental Science
    • /
    • v.39 no.1
    • /
    • pp.55-64
    • /
    • 2023
  • Properties of a lesser-used wood species were investigated to determine its potential for structural utilization. Trees of Delonix regia were felled and sampled at the base, middle and top and then sectioned to inner wood, middle wood, and outer wood for variation across the axial and radial directions. Hence, selected physical and mechanical properties as well as natural durability of D. regia along the radial and axial directions were examined. Obtained data were analyzed using analysis of variance (ANOVA) at α0.05. There was no significant difference in the Moisture content (MC) of the wood but specific gravity (SG) decreased from base to top ranging from 0.35-0.44. Water absorption, volumetric swelling, and volumetric shrinkage range from 46.18-51.86%, 2.57-4.02%, and 2.26-3.96% respectively along the axial plane. The weight loss for graveyard exposure and accelerated laboratory decay test ranged from 25.14-48.00% and 32.02-44.45% respectively. Modulus of Rupture and Modulus of Elasticity values range from 29.42-72.68 Nmm2 and 3,834.54-8,830.37 Nmm2 respectively. The SG values has confirmed the species as a medium density wood and values of other properties tested showed that the wood is dimensional stable and moderately resistance to fungi and termite. Hence, it could be used for light construction purposes such as furniture and other interior woodwork.