Arch System Research Articles

Numerical analyses in the design of umbrella arch systems

Due to advances in numerical modelling, it is possible to capture complex support-ground interaction in two dimensions and three dimensions for mechanical analysis of complex tunnel support systems, although such analysis may still be too complex for routine design calculations. One such system is the forepole element, installed within the umbrella arch temporary support system for tunnels, which warrants such support measures. A review of engineering literature illustrates that a lack of design standards exists regarding the use of forepole elements. Therefore, when designing such support, designers must employ complex numerical models combined with engineering judgement. With reference to past developments by others and new investigations conducted by the authors on the Driskos tunnel in Greece and the Istanbul metro, this paper illustrates how advanced numerical modelling tools can facilitate understanding of the influences of design parameters associated with the use of forepole elements. In addition, this paper highlights the complexity of the ground-support interaction when simulated with two-dimensional (2D) finite element software using a homogenous reinforced region, and three-dimensional (3D) finite difference software using structural elements. This paper further illustrates sequential optimisation of two design parameters (spacing and overlap) using numerical modelling. With regard to capturing system behaviour in the region between forepoles for the purpose of dimensioning spacing, this paper employs three distinctive advanced numerical models: particle codes, continuous finite element models with joint set and Voronoi blocks. Finally, to capture the behaviour/failure ahead of the tunnel face (overlap parameter), 2D axisymmetric models are employed. Finally, conclusions of 2D and 3D numerical assessment on the Driskos tunnel are drawn. The data enriched case study is examined to determine an optimum design, based on the proposed optimisation of design parameters, of forepole elements related to the site-specific considerations.

Biomechanics and force system of butterfly arch: A device for three-dimensional controlling of upper molars.

There are numerous intra-oral appliances that are used for many purposes in orthodontic practice. Some popular instances include those for anchorage preservation, distalizing plates, and expansion appliances. In maximum anchorage extraction cases, which are serious challenges for orthodontists, none of intra-oral devices can preserve the anchorage precisely. Butterfly arch with its unique design, configuration, and biomechanical properties is introduced here as a device that could enhance the posterior anchorage meticulously. In addition, there are several advantages mentioned here to present the importance of the appliance to preserve the vertical and transverse dimensions as well.

Structural and Economic Viability of 2D/3D Finite Element Analysis of Conical Arched Roof Truss

Arch and conical roof trusses are employed when dealing with large span roof trusses. But a combination of the two geometrical shapes may lead to a better economical sections and a means of dealing with larger spans of roof truss that are not suitable for an arch or conical roof truss. Consequently, this paper examines the structural and economic viability of arched conical roof truss system based on 2D/3D finite element method analysis. Analysis of the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which will result to overdesign of the structural members and the attendant high construction cost. There are some variations observed in the axial forces for trusses located at edges of polygon when compared with the trusses located mid-point between two polygonal edges. This observation is quite significant in the sizes of the steel section properties of the members as well as in the fabrication and installation cost.

Homoclinic orbits in a shallow arch subjected to periodic excitation

Homoclinic orbits in a shallow arch subjected to periodic excitation are investigated in the presence of 1:1 internal resonance and external resonance. The method of multiple scales is used to obtain a set of near-integrable systems. The geometric singular perturbation method and Melnikov method are employed to show the existence of the one-bump and multi-bump homoclinic orbits that connect equilibria in a resonance band of the slow manifold. These orbits arise from singular homoclinic orbits and are composed of alternating slow and fast pieces. The result obtained imply the existence of the amplitude-modulated chaos for the Smale horseshoe sense in the class of shallow arch systems.

Construction Control of a Continuous Beam Arch Composite Bridge

The geometric shape and internal forces were monitored during the construction of the hypostatic framework structure which is a composite system of steel beam and arch. The displace settlement was measured for the control of the geometric shape. And nine vibrating wire strain gauges were embedded on the key sections for the real time control of internal force. In order to cancel out the interference of the temperature variation effectively, displace settlement and internal forces were monitored around the clock at different time points. Then the measured values were compared with the theoretical values. Based on the measurement of temperature variation and strain, the settlement during the process of frame construction can be surely ascribed to thermal stress in the high redundancy structure. It should pay close attention to the changes in the future similar steel Beam Arch Composite Bridge construction and monitoring system.

Anatomic variations of aortic arch branching pattern (543.11)

The aortic arch branching pattern was examined in 39 cadaver specimens. The classic branching pattern of the aortic arch consists of the brachiocephalic trunk, left common carotid, and left subclavian arteries.The left and right vertebral arteries are normally branches of the left and right subclavian arteries, respectively.The present study demonstrates variant occurrence of the left common carotid and the left vertebral arteries. The left common carotid in one cadaver originated from the base of the brachiocephalic artery, crossed to the left side anterior to the trachea and then ascended on the left side of the cervical region. This anomaly can have various effects on the hemodynamics of the cerebral circulation and should be identified before performing any surgical procedures involving the aortic arch. In a separate cadaver, the left vertebral artery originated from the aortic arch, approximately 5mm posterior to the origin of the left subclavian artery. The anomalous left vertebral artery measured 7.34mm in diameter, while the right vertebral artery measured 7.26mm. The origin of the left vertebral artery from the aortic arch is significant as it has been associated with a higher incidence of arterial dissection than a left vertebral artery of subclavian origin. Anomalies in the aortic arch branching pattern are likely due to atypical development of the embryonic aortic arch system. A complete understanding of the normal aortic arch branching pattern, as well as its possible variations is vital to successful surgical and medical management of vascular pathologies.

Modelling of solid and hollow voussoir FlexiArch systems

This paper investigates the use of solid and hollow core voussoir blocks in an innovative FlexiArch bridge system. The system is formed from precast concrete voussoirs connected by a polymeric reinforcement, enabling the arch to be built and transported as a flat pack and lifted into shape after delivery to site, thus avoiding the use of centring for construction. This research is novel in that it trials and compares the use of hollow core and solid FlexiArch rings in third-scale models with granular backfill. The use of hollow core voussoirs reduces the loading on the polymeric reinforcement during construction and should allow for increased spans. This paper presents the test results of two similar third-scale 5 m × 2 m (span × rise) arch systems, using both solid and hollow construction. The use of hollow core voussoir blocks reduces the weight of the system. Non-linear finite-element analysis (NLFEA) has been used to further compare arch behaviour and the thrustline position.

Determination and analysis of phreatic water evaporation in extra-arid dune region

Extra-arid desert is a terminal of biological geochemistry circulation system. It has important value in scientific research and huge new discoveries, which is very useful in many regions, such as energy resources, mineral, water resources, ecology, biodiversity, tourism and characteristic agriculture. Meanwhile, extra-arid area’s desertification is a serious threat to the ecological safety of earth. Aeolian desertification is one of style of desertification caused by water shortage. Once desert has formed, it is very difficult to management or recovery. One of most effective methods for desert control is using integrated ecosystem management based on considering water and the soil. Therefore, it is very important to find a new available water resource, and authors’ research is in this field. In this paper, we select a Gobi on Dunhuang Mogao Grottoes of Kumtag desert fringe, where the buried depth of phreatic water is over 200m. Using an arched shed-air conditioning system, where covered drift sand thickness of 2.0m, the phreatic evaporation was measured for the first time. In order to analyze influence factors, the evaporation of phreatic water on Gobi was measured and compared. The temperature of soil and air, the humidity inside and outside of the arched shed were also monitored. It is found that the phreatic water under sand can go through sand layer and get to surface, which forms evaporation. The amount of evaporation changes along with solar radiation and temperature fluctuations in the day. It also changes periodically in the year. During five months from June to October, the sunshine time is longer and temperature is higher, and the evaporation is higher too, and the mean daily evaporation is 3.6g/(m2d). In other periods, the amount of evaporation of phreatic water is extremely weak. It is difficult to monitor by the arched shed-air conditioning system. Compared with Gobi region, the amount of evaporation of phreatic water on dune is very low, which is only 15.0% evaporation on Gobi. The key reason is the difference of salts in soil. The crystal water could be decomposed from salts or combined again. This reversible process plays a key role in transferring phreatic water of dune and Gobi. The amount of phreatic evaporation is proportional to the salts content in shallow soil. The salts content in dune is only 0.7% of salts content in Gobi, and water content in dune is 3.2% of the Gobi soil. According to results of monitoring, the water content is low in sand. The crystal water in shifting sand could be completely decomposed from salts with temperature rising. It causes relative humidity (RH) decreasing, which is inversely in the sand compared to in Gobi soil. In depth of 10cm sand, the daily fluctuation is about 10%, which is significantly higher than that of in Gobi soil (3%). As the crystalline salt is a kind of typical water carrier, decreasing the content of crystalline salt results to reduce water transporting because carrying capacity of water is significantly reduced. After condensing and collecting 168days, 9808g of water was outputted from sand. However, the water content in sand was still obviously higher than original content. That means the underground vapor migrates upward, and the phreatic water moves to surface. From the evaporation comparison of dune and Gobi, we can conclude that the amount of evaporation could be controlled by changing the soil property in interface, this points out the direction for utilization of phreatic water evaporation.

Kommerell diverticulum is a rare phenomenon: Aberrant left subclavian artery in association with right aortic arch and ventricular septal defect.

Kommerell´s diverticulum can occur in a number of anomalies of the aortic arch system that can, but do not always, cause symptoms of tracheal or esophageal compression. The diverticulum is most frequently present in cases of right aortic arch with an aberrant left subclavian artery. In this anomaly, the left subclavian artery arises from the right-sided aortic arch as the 4th branch and extends behind the esophagus to the left arm. The descending aorta can be right sided or left sided. We report a 5-year-old girl with Kommerel diverticulum, minor left upper extremity anomalies and restrictive perimembranous ventricular septal defect.

Structural Performance of Precast Concrete Arch with Reinforced Joint

내구성과 미관성이 우수한 석조 아치교량은 단경간 교량으로서 가장 오래되고 경험적으로 시공되었던 구조물로서 유럽에서는 지금까지도 현장에 시공되고 있으며, 이에 대한 활발한 연구가 진행되고 있다. 그러나 국내에서는 시공법의 비효율성과 비경제성으로 인해 교량 목적으로 시공되는 경우는 거의 없는 상태이다. 따라서 본 연구에서는 기존 연구자들이 제안한 시스템에서 구조성능의 향상이 가능한 보강된 이음부의 접합방법을 제안하였다. 제안된 이음부는 횡방향 루프이음과 종방향 보강근을 적용한 형식으로 프리캐스트 콘크리트 블록으로 이루어진 아치에 적용하여 실험을 통해서 구조적 성능을 평가하였다. 실험결과, 보강된 이음부는 소량의 보강근으로도 블록 상호 간의 상대변위와 힌지거동을 억제시켜 기존의 형식보다 충분한 내력을 향상시킬 수 있을 것으로 판단된다. The masonry stone arch bridge, due to its superior durability and aesthetics, has been one of the oldest and popular types of short span bridges. In Europe, this type of bridges have been continuously constructed, and numerous related researches have been conducted until recently. However, there are few construction cases in Korea since the economic efficiency and the construction effectiveness is not contentable. Therefore, this study proposed the reinforced joint to improve structural performance of the conventional arch systems which is proposed by previous researchers. The structural performance of the proposed reinforced joint, which consists of the transverse loop joint and the longitudinal reinforcement, is validated by experimental test of an arch bridge which is constructed using precast concrete segments. Based on this results of the experimental test, it is concluded that the strength of arch bridges can be enhanced by applying the proposed reinforced joints since the reinforced joint restrains hinge behavior and relative displacement between segments with a little reinforcement.

Full-Scale Test on Precast Concrete Arch Bridge with Reinforced Joint and Backfill

본 연구에서는 기존 연구자들이 제안한 석조형식의 아치시스템에서 보강된 이음부와 뒤채움이 고려된 아치교량의 실물모형에 대한 재하실험을 수행하였다. 실물모형교량의 실험체는 10 m (경간) <TEX>${\times}$</TEX> 3 m (높이)과 10 m (경간) <TEX>${\times}$</TEX>2 m(높이)이며, 실험체 폭은 2 m로 동일하게 하였다. 예비해석결과로부터 구조적으로 가장 취약한 하중위치는 경간의 1/3로 나타났고 그 결과를 토대로 구조실험시 하중재하위치, 측정 항목 및 위치를 결정하였다. 실험결과, 최대 내력은 높이/경간 비가 상대적으로 작은 실험체 <TEX>$10m{\times}2m$</TEX>가 실험체 <TEX>$10m{\times}3m$</TEX>보다 크게 나타났다. 실험체 모두 설계하중에 대하여 충분한 구조적 성능을 확보하는 것으로 평가되었다. In this paper, the load test of full-scale precast concrete arch bridges considering reinforced joint and backfill was conducted. It is an improved method that the reinforced joint enhanced the structural performance of conventional masonry arch system which was proposed by previous researchers. The models of full-scale test are <TEX>$10m(span){\times}3m$</TEX> (rise) and <TEX>$10m(span){\times}2m$</TEX> (rise), which are 2 meters in width. The critical load position was shown at a third-span from the results of the pre-analysis. Based on the this results, the positions of load, measuring items and points were determined in experiments. As a result, the maximum load capacity of the specimen <TEX>$10m{\times}2m$</TEX>, a relatively small rise to span ratio (compared to the specimen <TEX>$10m{\times}3m$</TEX>), was higher than the specimen <TEX>$10m{\times}3m$</TEX>. It was evaluated that all the specimens have sufficient structural performance on the design load.

Experimental investigation on the shear performance of prestressed self-compacting concrete beams without stirrups

In this work, eight prestressed reinforced self-compacting concrete (SCC) beams were tested in order to investigate the shear stresses transfer mechanism, the shear failure mode and the shear performance of prestressed SCC beams without stirrups. The principal parameters included concrete compressive strength, longitudinal tensile reinforcement ratio ρl and prestressing force. The results indicated that the shear resistance corresponding to the first flexure-shear crack increases with the amount of longitudinal tensile reinforcement and the prestressing force. The ultimate shear resistance Vu increases with the increase of the concrete compressive strength. Vu increases also with ρl and the prestressing force. The failure mode of the tested beams is similar to a reinforced normal concrete beams without stirrups, namely diagonal compression failure. The diagonal crack location was analyzed in this work and the values obtained are acceptable in comparison with the test data. The shear transfer mechanism can be explained by an arch system. The predictions provided by ACI and Eurocode were compared with those obtained by the experimental test.

Technique de couverture des traumatismes balistiques transfixiants de la main : intérêt du lambeau scapulaire bifolié libre. À propos d’un cas

Balistic transfixing hand traumas require a complex reconstruction management. Stabilization and reconstruction of the injuried tissues need a double skin-paddle coverage. We present an original case report of a double skin-paddle scapular/parascapular free flap used to cover a through and through gunshot injury of the right hand. A 14-years-old patient presents a severe and extensive wound with full-thickness palmar and dorsal skin defects, dislocation of the carpal bones, median nerve and flexor tendons losses. Distal vascularization is maintained by the deep palmar arch system supplied by the ulnar artery. The radial artery is severed at the level of the first dorsal interosseous space. The measured defect of the dorsal skin was 12×7cm and the palmar one was 6×3cm. After skeletal stabilization, tendinous and nerve preparation, the hand coverage was performed using a double skin-paddle scapular/parascapular free flap. The vascular anastomoses include an end-to-side arterial suture between the circumflex scapular and the radial arteries, and an end-to-end venous suture between the circumflex scapular and the dorsal radial veins. The scapular/parascapular double skin-paddle free flap is a safe and reliable technique to achieve a dorsal and palmar hand coverage in lack of local flaps alternatives. It can be used as a good option prior to bone graft, tendinous and nervous reconstruction.

Late diagnosis of double aortic arch: Consequences on long‐term follow‐up

Double aortic arch is the most common congenital anomaly of the aortic arch system, in which the trachea and esophagus are completely encircled by vascular segments of the aortic arch and its branches, often resulting in variable airway compression. One case of late diagnosis of this congenital malformation and long-term consequences of late surgical treatment with persistent tracheo-broncomalacia and dynamic airway obstruction is reported. This report emphasizes the importance of an early diagnosis to minimise the progressive airways damage and subsequent respiratory symptoms, that need an accurate medical follow-up.

Development of the human aortic arch system captured in an interactive three‐dimensional reference model

Variations and mutations in the human genome, such as 22q11.2 microdeletion, can increase the risk for congenital defects, including aortic arch malformations. Animal models are increasingly expanding our molecular and genetic insights into aortic arch development. However, in order to justify animal-to-human extrapolations, a human morphological, and molecular reference model would be of great value, but is currently lacking. Here, we present interactive three-dimensional reconstructions of the developing human aortic arch system, supplemented with the protein distribution of developmental markers for patterning and growth, including T-box transcription factor TBX1, a major candidate for the phenotypes found in patients with the 22q11.2 microdeletion. These reconstructions and expression data facilitate unbiased interpretations, and reveal previously unappreciated aspects of human aortic arch development. Based on our reconstructions and on reported congenital anomalies of the pulmonary trunk and tributaries, we postulate that the pulmonary arteries originate from the aortic sac, rather than from the sixth pharyngeal arch arteries. Similar to mouse, TBX1 is expressed in pharyngeal mesenchyme and epithelia. The endothelium of the pharyngeal arch arteries is largely negative for TBX1 and family member TBX2 but expresses neural crest marker AP2α, which gradually decreases with ongoing development of vascular smooth muscle. At early stages, the pharyngeal arch arteries, aortic sac, and the dorsal aortae in particular were largely negative for proliferation marker Ki67, potentially an important parameter during aortic arch system remodeling. Together, our data support current animal-to-human extrapolations and future genetic and molecular analyses using animal models of congenital heart disease. © 2013 Wiley Periodicals, Inc.

A Rare Cause of Respiratory Distress in the Newborn: Vascular Ring Anomaly

Aortic arch abnormalities which emerge as a result of the abnormal regression of the bronchial arch system during fetal life, may completely or partially surround the trachea and/or esophagus leading to respiratory system symptoms. Such abnormalities may cause a severe respiratory distress immediately after birth or can remain asymptomatic during the entire life period of the individual. However, many children with a vascular ring anomaly may present with dyspnea, coughing, lung infections, stridor or dysphagia. An increasing inspiratory stridor and cyanosis developed in a term neonate, after a feeding event. He had been hospitalized with diagnosis of pneumoniae showing signs of respiratory distress and feeding difficulty. Laryngoscopic examination revealed normal findings, but an echocardiogram of the infant demonstrated an aortic arch abnormality. Barium scan displayed an indentation on the esophagus and a HRCT confirmed the diagnosis of a double aortic arch, and the baby was operated. He is currently followed at the outpatient clinic as his symptoms disappeared after surgery. In conclusion, respiratory system symptoms in neonates, particularly when a stridor event is present, must make us consider vascular ring abnormality in the differential diagnosis.

효율개선을 위한 다중제어 인버터방식의 아치형 PV System 성능 분석

태양전지를 실제적인 건물의 한 구성요소로 이용하는 건물일체형 태양광발전(BIPV : Building Integrated Photovoltaic) 시스템은 기존의 건물재료를 대체하여 재료비용 및 건설비용의 절감효과를 가져다주며 건물의 미적인 가치를 높여주는 장점을 가지고 있다. BIPV에 대한 연구가 유럽 및 미국, 일본 등의 나라에서 오래전부터 활발히 수행되고 있으며, 시장성 또한 무한 확대되고 있다. 아치형 PV 시스템은 PV 어레이의 직병렬 연결 상태 및 아치각에 따라 효율 특성이 상이하지만 이에 관한 분석은 미흡하며, 아치형 PV 시스템을 설계함에 있어서 미적인 요소만 고려하고 이러한 발전효율에 관한 요소는 전혀 고려되지 않은 채 설계되고 있다. 본 논문에서는 아치형 PV 시스템의 효율에 관한 파라미터인 위도와 경도, 온도 및 일사량, 아치각, 시스템 구성에 따른 각종 손실 등 이에 대한 세부적인 기술검토와 각 장비들의 특성을 정합시켜 아치형 PV 시스템의 최적화를 이루어 효율을 개선시키고자 한다. 아치형 PV 시스템의 효율개선을 위하여 다중제어 인버터 방식을 제안하고 시뮬레이션 툴인 Solar Pro를 이용하여 평판형 및 다양한 아치형 PV 시스템을 구성하여 운전특성을 비교 분석하였다. It is saving material cost and construction cost by replacing conventional building materials, and It has advantages for aesthetic value. In the Europe, the United States, Japan and other country research about BIPV is actively being carried out and marketability is also being infinity expanding. Arch type PV systems efficiency characteristics is different depending on PV array's directly connection, parallel connection and arches angle, but is a lack of analysis on this nowadays. When the arch type PV system design up, they consider about aesthetic value and they didn't consider about generation efficiency. In this paper, we try to improve the efficiency through optimization of arch type PV system and estimation of the efficiency parameters of the arch type PV system, such as latitude, longitude, temperature, insolation, arch angle and each kind loss from system organization. For improving Arched PV system efficiency, proposed multiple control inverter system, and using simulation tool of Arched PV system "Solar pro", flat-plate type and many arch type PV system configuration the driving characteristics were compared and analyzed.

Hairy polyp of the oropharynx in association with a first branchial arch sinus

Hairy polyps are rare, congenital malformations of the oropharynx and nasopharynx. To date, approximately 145 cases have been reported. However, the histogenesis of these lesions remains unclear. We report the case of a 2-day-old neonate presenting with a hairy polyp attached to the left palate, who re-presented aged 16 months with a discharging first branchial arch sinus. We propose this case as supporting evidence for the theory that hairy polyps are a malformation of the first branchial arch system.

Coronal Mass Ejections and the Index of Effective Solar Multipole

The paper considers the relationship between the cyclic variations in the velocity of coronal mass ejections (CME) and the large-scale magnetic field structure (LSMF) in cycles 21 – 23. To characterize a typical size of the LSMF structure, we have used the index of the effective solar multipole (ESMI). The cyclic behavior of the CME occurrence rate and velocity proved to be similar to that of ESMI. The hysteresis observed in variations of the CME maximum velocity is interpreted as a manifestation of different contributions from the two field structures (local and global magnetic fields) in different phases of the 11-year activity cycle. It is suggested that cyclic variations in the maximum velocity of coronal mass ejections are due to different conditions for the formation of the complexes of active regions connected by coronal arch systems, which are the main source of high-velocity CMEs.

Anomalías inusuales del arco branquial, dermoepidérmicas y del sistema nervioso en un neonato con el síndrome VACTERL-H

VACTERL-H syndrome is a complex disorder of congenital malformations that implies vertebrae, anus, heart, trachea, esophagus, kidneys, limbs and hydrocephalus. Its etiology has been identified in a fraction of patients largely due to their sporadic nature and its high degree of clinical heterogeneity. This report presents a newborn with VACTERL-H syndrome, associated with unusual branchial arch, dermoepidermal and nervous system anomalies, which are compared with those described in the medical literature. Based on our experience, the presentation of this case not only expands the knowledge of the spectrum of anomalies that can occur in VACTERL-H syndrome, but also can be useful in identifying patients with this heterogeneous phenotype.