Arch System Research Articles

Clinical study on freehand of bicortical sacral screw fixation with the assistance of torque measurement device

BackgroundSacral screw loosening is a typical complication after internal fixation surgery through the vertebral arch system. Bicortical fixation can successfully prevent screw loosening, and how improving the rate of bicortical fixation is a challenging clinical investigation.ObjectiveTo investigate the feasibility of improving the double corticality of sacral screws and the optimal fixation depth to achieve double cortical fixation by combining the torque measurement method with bare hands.MethodsNinety-seven cases of posterior lumbar internal fixation with pedicle root system were included in this study. Based on the tactile feedback of the surgeon indicating the expected penetration of the screw into the contralateral cortex of the sacrum, the screws were further rotated by 180°, 360°, or 720°, categorized into the bicortical 180° group, bicortical 360° group, and bicortical 720° group, respectively. Intraoperatively, the torque during screw insertion was recorded. Postoperatively, the rate of double-cortex engagement was evaluated at 7 days, and screw loosening was assessed at 1 year follow-up.ResultsThe bicortical rates of the 180° group, 360° group, and 720° group were 66.13%, 91.18% and 93.75%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05).The rates of loosening of sacral screws in the 180° group, 360° group, and 720° group were 20.97%, 7.35% and 7.81%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05). The bicortical 360° group achieved a relatively satisfactory rate of dual cortical purchase while maintaining a lower rate of screw loosening.ConclusionManual insertion of sacral screws with the assistance of a torque measurement device can achieve a relatively satisfactory dual cortical purchase rate while reducing patient hospitalization costs.

Analysis on Performance of Arched Photovoltaic System

Analysis on Performance of Arched Photovoltaic System

The effect of Kahramanmaraş earthquakes on historical Malatya Yeni Mosque

The earthquakes that occurred on February 6, 2023, in Kahramanmaraş, Turkiye, caused extensive damage, particularly in historical mosques built with traditional methods. This study aims to investigate the collapse mechanism of Malatya Yeni Mosque, which underwent a strengthening operation before the Kahramanmaraş Earthquakes. The primary objective of this study is to offer insights into the rehabilitation of similar structures. Post-earthquake field surveys, combined with finite element modeling and dynamic analysis using city center acceleration data from Malatya, were utilized to assess structural vulnerabilities. The results of numerical analyses and field studies have indicated that seismic damages generally occurred in specific Mosque areas, particularly in the domes, minarets, columns (elephant feet), and arch systems supporting the central dome. The observed damage patterns in these areas signify the zones where the structural inadequacies generally coincide. The main findings of this study shed light on the necessity of strengthening these unique structures exposed to seismic forces and offer an essential step in minimizing the adverse effects of such disasters in the future. This study guides the planning and implementation of efficacious engineering interventions to preserve historical buildings.

Endovascular aortic arch repair under monitored anaesthesia care: maximizing microinvasiveness.

Patients with aortic arch pathologies after surgery for type-A acute aortic dissection represent a challenging population since open surgery is associated with a non-negligible rate of mortality and complications. Microinvasive endovascular aortic arch repair Arch-Thoracic EndoVascular Aortic Repair (Ar-TEVAR) has shown promising results in high-risk patients. Ar-TEVAR is usually performed under general anaesthesia. We report the case of an 83-year-old man with a history of ascending aorta replacement for type-A acute aortic dissection who was referred for an anastomotic pseudoaneurysm. Ar-TEVAR using an off-the-shelf single-branch aortic arch stent graft was chosen. In order to further minimize procedural invasiveness, monitored anaesthesia care (local anaesthesia with sedation and analgesia) was performed since it provides less stress on the cardiovascular and respiratory systems and overall leads to a faster recovery especially in elderly patients.

Static performance of precast concrete arches with carbon fiber reinforced polymer reinforcement

In this paper, static performances of a new precast concrete arch system with carbon fiber reinforced polymer (CFRP) reinforcement were investigated. Varied concrete strengths and segment types of precast concrete arches were tested. The results show that the increase of concrete strength can improve the bearing capacity of the precast arches with CFRP reinforcement. The ultimate bearing capacity of the precast arches segmented at the arch vault with CFRP reinforcement can reach or even exceed that of complete arches, while the precast arch segmented at the shoulder had lower ultimate load. A theoretical analysis method was proposed to predict the failure and bearing capacity of the precast concrete arches with CFRP reinforcement, which were found to be in close agreement with the experimental result.

Coupled dynamic instability of graphene platelet-reinforced dielectric porous arches under electromechanical loading

Graphene platelet-reinforced dielectric porous (GPLRDP) arches are a kind of multifunctional structures, which can be used to design various dielectric resonators and soft robotic components. This work studies the coupled dynamic instability of GPLRDP arches under electromechanical loading. It is assumed that the presence of voids is uniformly distributed in the arch structure, while graphene platelets (GPLs) are uniformly dispersed inside the skeleton of such voids. The effective medium theory (EMT) is used to determine the effective dielectric permittivity and Young's modulus of such structures. Based on the Hamilton principle, the governing equations of this problem are formulated. The differential quadrature method (DQM) and the Bolotin method are then used for solving the arch system to identify the coupled dynamic instability region. In this study, we observe the coupling effect of parametric and forced resonance phenomena. A series of numerical experiments are also carried out to examine the influence of porosities, GPL weight fractions, boundary conditions, and electrical voltage levels on the critical excitation frequency and coupled dynamic instability behavior of GPLRDP arches. It is found that the coupled dynamic instability region becomes wider and shifts to low frequency as the effect of porosity increases. When the signal amplitude of AC frequency is within a certain range, there is an abrupt increase of the critical excitation frequency under a high level of DC voltage. The numerical results of this work demonstrate that the location and size of the coupled dynamic instability region can be actively controlled by adjusting the material and structural parameters.

Optimal bracing system design for funicular twin arches against out-of-plane buckling

Twin arch bridges are often designed with a bracing member system that can significantly enhance the out-of-plane stability. This study presents an exact matrix stiffness method (MSM) for the out-of-plane buckling analysis of funicular twin arch bridges and investigates the optimal bracing system design. A novel 14 × 14 s-order element stiffness matrix of three-dimensional beam–columns was used in the MSM and the out-of-plane buckling analysis was performed after assembling the exact global structural stability stiffness matrix. The influences of the bracing location, number, length, and flexural rigidity of both the transverse bracing and X-bracing systems on the buckling capacity of the twin arch system were investigated. The in-plane stiffness of the bracing system (i.e., the horizontal flexural rigidity in a transverse bracing system) was found to be the critical factor in suppressing the out-of-plane buckling of the twin arch system. In addition, the twin arch system achieved the maximum out-of-plane buckling capacity with the bracing location at S/4, where S is the total arc length. For optimal bracing system design of funicular twin arches, it is recommended that one uses the more economical X-bracing system or a transverse bracing system with adequately rigid bracing members.

Diversity of filter feeding and variations in cross-flow filtration of five ram-feeding fish species

IntroductionFilter-feeding fish separate food particles from the surrounding water by cross-flow filtration in which a suspension flows parallel to a porous filter medium, thereby transporting particles along the surface.MethodsHere, we investigate cross-flow filtration in five ram-feeding fish species from two groups, Scombridae (Scomber scombrus and Rastrelliger kanagurta) and Clupeidae (Clupea harengus, Sardina pilchardus, and Engraulis encrasicolus). Using a combination of morphometrics, micro-CT scanning, video analysis, and water tunnel experiments, we give a detailed description of the gill arch system, calculate filtration parameters, observe particle movement, and identify morphological traits that induce cross-flow filtration.ResultsOur findings suggest that these ram-feeding fish species use a combination of cross-flow and dead-end filtration as the underlying filtration principle. Specifically, the particles are transported along the surface of gill rakers and denticles towards the esophagus where they accumulate before being periodically swallowed. We infer three distinct morphotypes characterized by variations in geometry, mesh size, and surface structures, which indicate variations of the general mechanism.DiscussionThe description presented in this study contributes to the development of models for investigating the influence of morphological variation on fluid flow and particle retention in filter-feeding fish and on their ecology and biomimetic application.

Seismic Fragility Assessment for a Newly Developed Buried Arch Bridge

This study aims to assess the seismic response of a newly developed buried arch bridge system. The proposed buried arch bridge system is comprised of precast concrete panels, external steel outriggers, and steel V-strips to solve the limitation encountered in the storage, transportation, and construction of traditional buried arch structures. The three-dimensional finite element analysis of this arch system is conducted under dynamic analysis emphasizing the frequency content of earthquakes. Then, the fragility curves are suggested for this arch system based on two damage states defined via incremental dynamic analysis. The results show that this proposed arch system is significantly affected under a high frequency content earthquake compared to the low and intermediate ones. Additionally, the arch system deflects the most at the mid-high position rather than at the arch crown. The deflection at the arch crown or at the mid-high position can be used for establishing the fragility curves as they both connect with the failure mechanism of the arch structure.

Phenotypic and molecular basis of SIX1 variants linked to non-syndromic deafness and atypical branchio-otic syndrome in South Korea

Branchio-oto-renal (BOR)/branchio-otic (BO) syndrome is a rare disorder and exhibits clinically heterogenous phenotypes, marked by abnormalities in the ear, branchial arch, and renal system. Sporadic cases of atypical BOR/BO syndrome have been recently reported; however, evidence on genotype–phenotype correlations and molecular mechanisms of those cases is lacking. We herein identified five SIX1 heterozygous variants (c.307dupC:p.Leu103Profs*51, c.373G>A:p.Glu125Lys, c.386_391del:p.Tyr129_Cys130del, c.397_399del:p.Glu133del, and c.501G>C:p.Gln167His), including three novel variants, through whole-exome sequencing in five unrelated Korean families. All eight affected individuals with SIX1 variants displayed non-syndromic hearing loss (DFNA23) or atypical BO syndrome. The prevalence of major and minor criteria for BOR/BO syndrome was significantly reduced among individuals with SIX1 variants, compared to 15 BOR/BO syndrome families with EYA1 variants. All SIX1 variants interacted with the EYA1 wild-type; their complexes were localized in the nucleus except for the p.Leu103Profs*51 variant. All mutants also showed obvious but varying degrees of reduction in DNA binding affinity, leading to a significant decrease in transcriptional activity. This study presents the first report of SIX1 variants in South Korea, expanding the genotypic and phenotypic spectrum of SIX1 variants, characterized by DFNA23 or atypical BO syndrome, and refines the diverse molecular aspects of SIX1 variants according to the EYA1–SIX1–DNA complex theory.

Production parameters of novel geopolymer masonry mortar in heritage buildings: Application in masonry building elements

The aim of this study is to develop an innovative high-strength restoration mortar using recycled materials as an alternative to the mortars used in historical buildings. Compressive strength tests were carried out on the samples and, according to the results, the mortar giving the highest strength was determined as the optimum mixture. The compressive strength, shear strength, displacement and load-carrying capacity values of the masonry units were tested by using the geopolymer mortar with the highest strength among the mortar samples produced. The novelty of this research is that geopolymer repair mortars were produced as an alternative to standard mortars and applied in masonry building units. The results showed that blast furnace slag and brick powder can effectively improve the compressive and bond strength of the geopolymer. In the compressive strength tests performed on the samples, much higher strength results were obtained with geopolymer historical building mortar than standard historical building mortar. In the compressive and shear strength performed on the masonry units, the geopolymer historical building mortar showed higher mechanical properties compared to the standard historical building mortars. When the compressive strength test results are compared, a strength of 1.8 times was observed in the masonry unit (GHB1) produced using geopolymer historical building mortar, compared to the masonry unit (HB1) produced with standard historical building mortar. As a result of the shear strength test, the masonry unit (GHK1) produced with geopolymer mortar demonstrated seven times more load carrying capacity than the masonry unit (HK1) elements produced with standard historical building mortar. Moreover, the masonry arch systems produced with standard historical building mortar showed close load bearing capacity with the geopolymer historical building mortar, but the masonry arch element produced with geopolymer mortar exhibited a more ductile behavior. It has been determined that the use of geopolymer mortars with recycled materials with increasing molarity in masonry arch elements improves the compressive strength and accelerates the geopolymerization mechanism. Innovative high-strength geopolymer mortars used in masonry walls provided good adhesion with the hollow brick, creating a compact structure.

In Situ Measurement of Absorbing Properties of Materials Based on Near-Field Reflection Method

To meet the requirements of the in-situ measurement of the absorbing properties of materials and break through the limitations of the transmission line probe method in ultra-wideband and high-precision measurement, this paper presents in-situ measurement technology for the absorbing properties of materials based on near-field reflection testing. A miniaturized ultra-wideband antenna, a decoupling structure and a shielding cover are designed, and an in-situ measurement probe is constructed. By integrating the probe with a microwave transceiver module as well as a control processing module, a handheld broadband microwave reflectivity test instrument is developed and its performance is verified. The measurement accuracy of the proposed instrument is higher than that of transmission line probes, the deviation of its test results from those of standard arch systems is less than 1.5 dB in the reflectivity range of 0 to -20 dB; its test frequency band is wider, and its frequency band covers 2-18 GHz. The instrument is suitable for accurately measuring the absorbing properties of materials with thicknesses of less than 1.5 mm.

Seismic evaluation of the bridge with a hybrid system of cable and arch: Simultaneous effect of seismic hazard probabilities and vertical excitations

There are many parameters that affect the seismic behavior of the bridge, especially in the new type of bridges. In this research, the seismic behavior of a cable-arch bridge as a new type of bridge with a hybrid system of an arch and stay cables has been studied considering the effect of seismic hazard probabilities and vertical excitations. By considering these parameters, the seismic analysis was investigated in three steps: Response spectrum analysis to obtain general seismic behavior of the bridge, time-history analysis using seismic ground motion records to capture dynamic responses, and pushover analysis to determine the capacity of the bridge. The performance of the bridge was monitored, and the significance of considering seismic hazard probabilities and vertical excitations was investigated. Pointing out the effects of these parameters on the seismic behavior of the bridge, the results indicated a requirement for considering them to provide the seismic safety of the bridge.

Kommerell's diverticulum: an unusual cause of unilateral vocal cord palsy?

Kommerell's diverticulum is a rare congenital anomaly of the aortic arch system in which there is a left- or right-sided aortic arch with an aberrant subclavian artery on the contralateral side. Patients with this anomaly can be asymptomatic or have features of tracheal or oesophageal compression. However, there is a rising suspicion that it may be a rare cause of unilateral vocal cord palsy through its compression of the recurrent laryngeal nerve. We describe a patient who had a long history of hoarse voice and left vocal cord palsy with no other obvious cause, who was found to have a Kommerell's diverticulum on a contrast-enhanced computed tomography scan.

Robustness of the combined arch system with radial ties

To ensure the safety of buildings and structures, it is necessary to analyze the structural integrity (robustness). The results of various studies show that arches with radial ties make it possible to create an architecturally expressive, cost-effective material consumption solution to the problem of girders bridging in public buildings, but the robustness of these systems is poorly studied. This article presents the results of the failure analysis of the coating elements in the form of combined steel arches with radial ties under various failure scenarios, the robustness of the n-th level in a static formulation is investigated, considering the geometrically nonlinear nature of the system operation, constructive measures are proposed to increase the robustness of a combined arch system with radial ties. The calculations were performed in the SCAD Office software 21.1.9.11. For the considered fragment of the scheme in both scenarios, the robustness index Irob &gt; 98.5% corresponds to the local nature of the excess of the load-carrying ability, Irob ≤ 98.5% - to disproportional. As soon as the asymmetric prestressing of the arch by ties disappears, which occurs when the most loaded ties are turned off step by step, the system either satisfies the strength and stability tests, or the number of elements in which the load-carrying ability is exceeded significantly decreases. Increasing the structural integrity of the structure by introducing chordal ties into the scheme contributes to increasing the robustness of the considered arch system.

Development of technological equipment for autonomous testing of the shaping structure of the umbrella reflector

A shaping structure is element in most transformable reflectors to ensure the required accuracy of the reflective surface. An umbrella reflector shaping structure is a system of tensioned dimensionally stable cords in the open position. External factors influence the cords of the shaping structure, which lead to a change in the length of the cords throughout the entire life cycle of the product. It is advisable to assess the stability of the geometric dimensions of the cords, from the point of view of labor intensity, on a piece of the shaping structure – the arch system. To conduct this kind of research, there is a need to develop special technological equipment. The article considers the requirements for technological equipment and testing. The authors propose an original design of technological equipment, which allows fixing the cords of the arch system with boundary conditions similar to a real reflector. The paper describes a 3D model of the technological equipment, on the basis of which a prototype was made. The prototype ensured the assembly of a separate arch system corresponding to the standard design in terms of size, configuration and cord tension. Tests were carried out to assess the measurement error of the arch system in the manufactured experimental model. The test results confirmed the possibility of using the developed technological equipment for component tests of the shaping structure.

Conceptual design of long span steel-UHPC composite network arch bridge

An innovative half-through network arch bridge with a main span of 470 m was proposed and designed using coarse aggregate ultra-high-performance concrete (CA-UHPC) and steel. To effectively resist the tremendous axial forces, we utilized circular hollow section arch ribs with a CA-UHPC outer layer and an inner steel tube in this proposal. To minimize the bending moment of the arch ribs, we arranged the inclined crossed hangers above the deck and similarly the columns below the deck, connecting the arch ribs with the main girder, and adopting a structural system of double-hinged arches. By incorporating the recently developed multi-material bi-directional evolutionary structural optimization method and through various parametric studies, we determined the best configuration for the bridge. We also used finite element analysis to investigate the corresponding structural responses. The numerical analysis demonstrates that the proposed bridge has excellent mechanical performance in terms of stability, overall structural stiffness, stress, and fatigue strength of each component. A comprehensive comparison between the proposed bridge and the more conventional concrete-filled steel tube (CFST) arch bridge under the same conditions reveals that: the construction-related CO2 emissions of the proposed bridge are significantly lower than those of the CFST bridge, while the economic indicators are slightly better. The proposed bridge is simpler, slenderer, and more elegant. Due to its innovative design, the proposed bridge can overcome a series of problems associated with conventional bridges such as the excessive self-weight of long-span concrete arch bridges, the challenges of welding thick steel plates on all-steel arch bridges and the high cost of these structures, as well as the disadvantages of CFST arch bridges.

Application of BIM Technology in the Seismic Performance of “Wood Weaving” Structure of Wooden Arcade Bridges

The wood arch bridge has good seismic performance, and the “wood weaving” of its arch system is closely related. Wood weaving has the isolation function similar to that of rubber bearing isolation layer under earthquake, which is the key to ensuring good isolation performance of wood arch bridges. However, it is difficult to measure the seismic performance of the “wood woven” structure of the wooden arch bridge, which leads to its limited application. In order to solve this problem, building information model (BIM) technology is introduced into this field, and the application of BIM technology in the seismic performance of “wood woven” structures of wooden arch bridges needs research. First, the design principle of “wood weaving” is described, and then the seismic principle of “wood weaving” is analyzed. Finally, from the perspective of the structural strength index, the seismic performance of the wooden arch bridge “wooden woven” structure is analyzed in depth with BIM technology in order to provide some help for understanding the seismic performance of the wooden arch bridge “wooden woven” structure and promoting the effective application of wooden arch bridge.

2D geometric model of the human femoral neck in frontal projection

In modern society, life expectancy is steadily increasing, at the same time, the number of medial femoral fractures is increasing. The bone-beam system of the proximal epiphysis of the femur has areas of different density throughout, however, these differences are most clearly observed in the neck. The aim of the stidy was to build a two-dimensional parametric model of the human femoral neck to study its bone and beam structure. Material and methods. The study was carried out on 50 macerated femurs and 10 radiographs of human hip joints from the collection of the department of anatomy of I.P. Pavlov Ryazan State Medical University. All bones were without signs of bone pathology and had no growth zones. Age and gender determination was not performed. The material was photographed in frontal projection, then the photographs were transferred to a personal computer and measurements were taken in the Autodesk AutoCAD LT 2012 Commercial New SLM ML03 program. Using a mathematical model, the femoral neck was divided into three figures: "head–neck", "true neck", "neck–trochanteric region". We also measured the angles of the beginning of the increase in the diameter of the femoral neck: to the head (angles α1 and α2); and to the trochanteric region (angles β1 and β2), the angle γ, which characterizes the direction of a number of bundles of the arch system of the proximal epiphysis of the femur, was separately identified. Results. The “true neck” perimeter area was 213.23 [194.31; 250.51] mm2, which occupies 20% in the structure of the integral figure, and the parameters of the “neck–head” and “neck–trochanteric region” perimeters were 355.47 [ 321.47; 420.57] mm2 – 33% and 511.65 [447.11; 583.19] mm2 – 47%, respectively. The median values of the angle α1 were 34.24 [29.38; 40.45]°, angle α2 – 27.27 [22.30; 31.48] °, angle γ – 51.32[46.71; 55.39]°, while the angles β1 and β2 are 39.95 [35.39;42.93]° and 28.65 [25.70; 31.61] ° respectively. Conclusion. The proposed two-dimensional parametric model with the division of the neck into a number of figures makes it possible to mathematically evaluate the position, direction, and distribution of bone-beam structures in the proximal epiphysis.

Third-Order Effects and Maxillary Incisor Control in Lingual Orthodontics – A Finite Element Study of a Ribbon Arch and Edgewise Straight Wire System

Introduction: The aim of the present study was to analyze the effects of retraction mechanics on torque control when retraction forces were applied on the maxillary anterior dentition in two distinct lingual appliance systems. Materials and Methods: A three-dimensional bilateral maxillary model was created where the first premolar extraction case was included. 150 g (1.47 N) of retraction force was applied on each side from canine (C) hook to molar for both edgewise straight wire system and ribbonarch appliances. Results: In the edgewise appliance, it was observed in the X-axis that there was less amount of tipping of the six anterior teeth of the canine and central incisor (CI) when compared with the lateral incisor (LI) at occlusal point. In the Y-axis, overall extrusion was observed. In the Z-axis, there was less lingual crown movement. In the ribbonarch appliance, it was observed in the X-axis that there was less tipping, prominently in the canine and CI than in the LI. In the Y-axis, overall extrusion was observed. In the Z-axis, there was less lingual crown movement, whereas the CI and canine showed less movement when compared with the LI. Conclusions: It was observed that there was greater torque loss and extrusion in the edgewise appliance along with greater maximum principal stress in the cervical half of the facial side in the periodontal ligament (PDL) and minimum principal stress on the cervical half of the palatal side in the PDL when compared with the ribbonarch appliance.