• Title/Summary/Keyword: Dilation

Search Result 584, Processing Time 0.024 seconds

Modeling of rock dilation and spalling in an underground opening at depth (대심도 지하공동에 발생하는 암반의 팽창 및 스폴링 현상 모델링)

  • Cho, Nam-Kak;Lee, Yong-Joo
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.12 no.1
    • /
    • pp.31-41
    • /
    • 2010
  • This paper presents both numerical and physical modeling approaches for the dilation and spalling of rock recognized as typical process of rock around an underground opening at depth. For physical approach, laboratory testing of rectangular beams using a synthetic rock was used to investigate the onset of dilation and spalling. The beams are axially compressed and subjected to 4-point bending to provide non-uniform compressive stresses which are similar to the maximum tangential stress distribution around circular openings. Discrete element numerical analyses using commercial code $PFC^{2D}$ (Particle Flow Code) were performed to evaluate the stress path at various locations in the beams. The findings from these approaches suggest that the onset of dilation in laboratory tests appears to be a good indicator for assessing the stress magnitudes required to initiate spalling.

DILATION OF PROJECTIVE ISOMETRIC REPRESENTATION ASSOCIATED WITH UNITARY MULTIPLIER

  • Im, Man Kyu;Ji, Un Cig;Kim, Young Yi;Park, Su Hyung
    • Journal of the Chungcheong Mathematical Society
    • /
    • v.20 no.4
    • /
    • pp.367-373
    • /
    • 2007
  • For a unital *-subalgebra of the space $\mathcal{L}^a(X)$ of all adjointable maps on a Hilbert $\mathcal{B}$-module X with a $C^*$-algebra $\mathcal{B}$, we study unitary operator (in such algebra)-valued multiplier ${\sigma}$ on a normal, generating subsemigroup S of a group G with its extension to G. A dilation of a projective isometric ${\sigma}$-representation of S is established as a projective unitary ${\rho}$-representation of G for a suitable unitary operator (in some algebra)-valued multiplier ${\rho}$ associated with the multiplier ${\sigma}$ which is explicitly constructed.

  • PDF

Study on the Evolution of Sand Structure during Shearing (전단시험 중 모래입자의 변형에 관한 연구)

  • 이석원
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2000.03b
    • /
    • pp.289-296
    • /
    • 2000
  • This paper summarizes the results of a study which has quantified the evolution of the structure of sands adjacent to geomembranes of varying roughness at different stages of shearing. The results show that the structure evolution, and hence shear mechanisms for rounded uniform sands adjacent to geomembranes, are directly influenced by the surface roughness of the geomembranes. For smooth geomembranes, the shear mechanism predominantly involves sliding of sand particles and only affects the sand structure within two particle diameters of the geomembrane. For slightly textured geomembranes, the effects of interlocking and dilation of sand particles extends the zone of evolution to four particles diameters from the interface. For moderately/heavily textured geomembranes, the interlocking and dilation of sand particles is fully developed and results in large dilation in the interfacial zone, which extends up to six particle diameters from the interface. By understanding how the structure of the sand adjacent to geomembranes of different roughness changes during shearing, it may be possible to identify alternative geomembrane roughening procedures and patterns that can lead to more efficient interface designs.

  • PDF

A Rupture of Proximal Ureter Caused by Renal Calculi in a Dog (개의 신장결석에 의한 근위요관파열의 1예)

  • 최민철;허진영;장동우;김완희;홍연정;윤정희;윤화영;권오경;이기창
    • Journal of Veterinary Clinics
    • /
    • v.17 no.1
    • /
    • pp.243-246
    • /
    • 2000
  • A 3-year old female Poodle dog was presented with a history of anorexia, vomiting, abdominal pain and depression for 2 days. After physical and blood examination, excretory urogram(EU) and ultrasonography of the abjomen were conducted. On radiographs and ultrasonographs, dilation of diverticulum, sinus, proximal ureter of right kidney and mild dilation of left renal medullar were found. And there was some leakage of contrast agent in the proximal ureter area of right kidney. So this was diagnosed as a rupture of right proximal ureter. This dog was undertaken a surgery of nephrectomy of right kidney. On surgery, dilation of right kidney and hemorrhage, adhesion were found at the proximal ureter and some calculi were also found in the pelvis of right kidney. There were no complications after surgery.

  • PDF

Diagnostic Imaging of Urological Diseases in Dogs (개에서 비뇨기계 질환의 진단영상)

  • 장동우;정주현;장진회;정우조;원성준;이기창;최호정;이희천;윤화영
    • Journal of Veterinary Clinics
    • /
    • v.18 no.4
    • /
    • pp.459-464
    • /
    • 2001
  • Excretory urography is a procedure where opacification of the kidneys, renal pelvic diverticula, ureters, and urinary bladder is a result of renal excretion of an intravenously administered iodinated contrast agent providing both anatomical and functional assessment. And ultrasonography is a non-invasive modality to evaluate the important anatomic information concerning the size, shape, and internal architecture of kidney even in the presence of impaired renal function or abdominal fluid. We describe four dogs with urological signs diagnosed with excretory urography and ultrasonography. Parients showed a variety of clinical signs including vomiting, hematuria, anorexia, abdominal pain, and abdominal distension. The hydronephrosis was diagnosed in case 1, 2, and 3 that had pelvic dilation, dilation of pelvic recesses, ureteral dilation. In case 3, proximal ureteral rupture was diagnosed with evidence of contrast media leakage was seen in proximal ureter. In case 4, the rupture of urinary bladder was diagnosed with leakage of contrast media through its ventral portion.

  • PDF

Effect of Dilation on the Mechanical Characterization of Vascular Prostheses

  • Ulcay Y.;Pourdeyhimi B.
    • Fibers and Polymers
    • /
    • v.6 no.1
    • /
    • pp.49-54
    • /
    • 2005
  • The purpose of this study has been to investigate the effect of dilation on the some mechanical properties of several types of warp-knitted vascular grafts. The structures of warp knit vascular grafts used in the experiments were reverse locknit, locknit, and Tricot. Various mechanical properties of these grafts were determined using devices developed for the purpose. Clinical data obtained were compared with experimental results of warp knit vascular grafts. The most important mechanical properties are found to be creep extension, bursting strengths, and compliance. Preliminary results indicate that vascular grafts are non-compliant and exhibit creep which is predictive of the long term dilation that has been noted in the clinical results. It is found that there is a positive correlation between experimental data and clinical results for at least the grafts tested.

Embedding between a Macro-Star Graph and a Matrix Star Graph (매크로-스타 그래프와 행렬 스타 그래프 사이의 임베딩)

  • Lee, Hyeong-Ok
    • The Transactions of the Korea Information Processing Society
    • /
    • v.6 no.3
    • /
    • pp.571-579
    • /
    • 1999
  • A Macro-Star graph which has a star graph as a basic module has node symmetry, maximum fault tolerance, and hierarchical decomposition property. And, it is an interconnection network which improves a network cost against a star graph. A matrix star graph also has such good properties of a Macro-Star graph and is an interconnection network which has a lower network cost than a Maco-Star graph. In this paper, we propose a method to embed between a Macro-Star graph and a matrix star graph. We show that a Macro-Star graph MS(k, n) can be embedded into a matrix star graph MS\ulcorner with dilation 2. In addition, we show that a matrix star graph MS\ulcorner can be embedded into a Macro-Star graph MS(k,n+1) with dilation 4 and average dilation 3 or less as well. This result means that several algorithms developed in a star graph can be simulated in a matrix star graph with constant cost.

  • PDF

Balloon dilation with triamcinolone intralesional injection successfully treated rectal stricture in a three-month kitten

  • Lee, Hee-Ryung;Adam, Gareeballah Osman;Lee, Sei-Jin;Kim, Shang-Jin
    • Korean Journal of Veterinary Research
    • /
    • v.60 no.1
    • /
    • pp.39-42
    • /
    • 2020
  • This report describes a three-month-old Korean domestic kitten presented with dehydration and poor body condition. Physical examination revealed abdominal distension. Rectal diagnosis was unachievable due to the small rectum diameter. X-ray radiography and endoscopy confirmed presence of abdominal distension and indicated a stricture located 1.5 cm from the anus. A balloon was gently inserted into the rectum and inflated several times followed by triamcinolone injection. Four months later, same procedures were repeated. This report is the first to describe the use of balloon dilation of a rectal stricture followed by intralesional triamcinolone injection in a small cat with poor condition.

The dilatancy and numerical simulation of failure behavior of granular materials based on Cosserat model

  • Chu, Xihua;Yu, Cun;Xu, Yuanjie
    • Interaction and multiscale mechanics
    • /
    • v.5 no.2
    • /
    • pp.157-168
    • /
    • 2012
  • The dilatancy of granular materials has significant influence on its mechanical behaviors. The dilation angle is taken as a constant in conventional associated or non-associated flow rules based on Drucker-Prager yields theory. However, various experimental results show the dilatancy changes during progressive failure of granular materials. A non-associated flow rule with evolution of dilation angle is adopted in this study, and Cosserat continuum theory is used to describe the behaviors of granular materials for considering to some extent the its internal structure. Numerical examples focus on the bearing capacity and localization of granular materials, and results illustrate the capability and performance of the presented model in modeling the effect on failure behavior of granular materials.

Embedding Algorithm among Folded Hypercube, Even Network and Odd Network (폴디드 하이퍼큐브와 이븐연결망, 오드연결망 사이의 임베딩 알고리즘)

  • Kim, Jong-Seok;Sim, Hyun;Lee, Hyeong-Ok
    • Journal of KIISE:Computer Systems and Theory
    • /
    • v.35 no.7
    • /
    • pp.318-326
    • /
    • 2008
  • In this paper, we will analyze embedding among Folded Hypercube, Even Network and Odd Network to further improve the network cost of Hypercube. We will show Folded Hypercube $FQ_n$ can be embedded into Even Network $E_{n-1}$ with dilation 2, congestion 1 and Even Network $E_d$ can be embedded into Folded Hypercube $FQ_{2d-3}$ with dilation 1. Also, we will prove Folded Hypercube $FQ_n$ can be embedded into Odd Network $O_{n-1}$ with dilation 2, congestion 1 and Odd Network $O_d$ can be embedded into Folded Hypercube $FQ_{2d-3}$ with dilation 2, congestion 1. Finally, we will show Even Network $E_d$ can be embedded into Odd Network $O_d$ with dilation 2, congestion 1 and Odd Network $O_d$ can be embedded into Folded Hypercube $E_{d-1}$ with dilation 2, congestion 1.